WorldWideScience

Sample records for random multiple access

  1. A Team Study of a Multiple-Power Wireless Random Channel Access Mechanism with Capture Effect

    Directory of Open Access Journals (Sweden)

    Abdelillah Karouit

    2013-01-01

    Full Text Available We present a team analysis of a slotted random wireless channel access mechanism. Under the proposed scheme, denoted wireless random access mechanism with multiple power levels (MPL-WRA, each mobile station contends for a transmission opportunity following the principles of a slotted access mechanism incorporating a random transmitting power value selected among various available power levels. In this way, a capture effect may be produced allowing the packet to be decoded whenever the signal-to-interference-plus-noise ratio is higher than a given threshold. In order to analyze the performance and optimization of the proposed setup, we build a Markovian model integrating the wireless access mechanism supplemented by the use of multiple power levels in an attractive and simple cross-layer fashion. We follow a team problem approach allowing us to fine tune the design parameters of the overall system configuration. Throughout an extensive numerical analysis, our main results set the basis for the social optimal system configuration of the proposed mechanism taking into account the physical constraints of using multiple power levels and the actual practical implementation of a slotted access mechanism. We end the paper with concluding remarks and future research directions including guidelines for the actual implementation of our proposal.

  2. Mobile multiple access study

    Science.gov (United States)

    1977-01-01

    Multiple access techniques (FDMA, CDMA, TDMA) for the mobile user and attempts to identify the current best technique are discussed. Traffic loading is considered as well as voice and data modulation and spacecraft and system design. Emphasis is placed on developing mobile terminal cost estimates for the selected design. In addition, design examples are presented for the alternative techniques of multiple access in order to compare with the selected technique.

  3. Coded Random Access

    DEFF Research Database (Denmark)

    Paolini, Enrico; Stefanovic, Cedomir; Liva, Gianluigi

    2015-01-01

    , in which the structure of the access protocol can be mapped to a structure of an erasure-correcting code defined on graph. This opens the possibility to use coding theory and tools for designing efficient random access protocols, offering markedly better performance than ALOHA. Several instances of coded......The rise of machine-to-machine communications has rekindled the interest in random access protocols as a support for a massive number of uncoordinatedly transmitting devices. The legacy ALOHA approach is developed under a collision model, where slots containing collided packets are considered...... as waste. However, if the common receiver (e.g., base station) is capable to store the collision slots and use them in a transmission recovery process based on successive interference cancellation, the design space for access protocols is radically expanded. We present the paradigm of coded random access...

  4. Well controlled multiple resistive switching states in the Al local doped HfO2 resistive random access memory device

    Science.gov (United States)

    Chen, Y. S.; Chen, B.; Gao, B.; Liu, L. F.; Liu, X. Y.; Kang, J. F.

    2013-04-01

    The resistive switching behaviors in the sandwiched Ti/HfO2/Pt devices with different doping condition were systematically investigated. We show that, comparing with the undoped and the Al layer doped HfO2 devices, significant improvement of switching characteristics is achieved in the Al local doped HfO2 device, including uniformity, reliability, and operation current. As a result, well controlled multiple switching states are obtained in the local doping device by modulating the set current compliance or the maximal reset voltage, respectively. Our results suggest that the switching characteristics of HfO2 device are very closely related to the inducement and controlling of conductive filaments' growth in the dielectric layer, which can be considered in the optimization of resistive random access memory device design.

  5. Uncorrelated multiple conductive filament nucleation and rupture in ultra-thin high-κ dielectric based resistive random access memory

    Science.gov (United States)

    Wu, Xing; Li, Kun; Raghavan, Nagarajan; Bosman, Michel; Wang, Qing-Xiao; Cha, Dongkyu; Zhang, Xi-Xiang; Pey, Kin-Leong

    2011-08-01

    Resistive switching in transition metal oxides could form the basis for next-generation non-volatile memory (NVM). It has been reported that the current in the high-conductivity state of several technologically relevant oxide materials flows through localized filaments, but these filaments have been characterized only individually, limiting our understanding of the possibility of multiple conductive filaments nucleation and rupture and the correlation kinetics of their evolution. In this study, direct visualization of uncorrelated multiple conductive filaments in ultra-thin HfO2-based high-κ dielectric resistive random access memory (RRAM) device has been achieved by high-resolution transmission electron microscopy (HRTEM), along with electron energy loss spectroscopy (EELS), for nanoscale chemical analysis. The locations of these multiple filaments are found to be spatially uncorrelated. The evolution of these microstructural changes and chemical properties of these filaments will provide a fundamental understanding of the switching mechanism for RRAM in thin oxide films and pave way for the investigation into improving the stability and scalability of switching memory devices.

  6. Uncorrelated multiple conductive filament nucleation and rupture in ultra-thin high-κ dielectric based resistive random access memory

    KAUST Repository

    Wu, Xing

    2011-08-29

    Resistive switching in transition metal oxides could form the basis for next-generation non-volatile memory (NVM). It has been reported that the current in the high-conductivity state of several technologically relevant oxide materials flows through localized filaments, but these filaments have been characterized only individually, limiting our understanding of the possibility of multiple conductive filaments nucleation and rupture and the correlation kinetics of their evolution. In this study, direct visualization of uncorrelated multiple conductive filaments in ultra-thin HfO2-based high-κ dielectricresistive random access memory (RRAM) device has been achieved by high-resolution transmission electron microscopy (HRTEM), along with electron energy loss spectroscopy(EELS), for nanoscale chemical analysis. The locations of these multiple filaments are found to be spatially uncorrelated. The evolution of these microstructural changes and chemical properties of these filaments will provide a fundamental understanding of the switching mechanism for RRAM in thin oxide films and pave way for the investigation into improving the stability and scalability of switching memory devices.

  7. Multiple Access Communications

    DEFF Research Database (Denmark)

    This book constitutes the proceedings of the 9th International Workshop on Multiple Access Communications, MACOM 2016, held in Aalborg, Denmark, in November 2016. The 10 full papers presented in this volume were carefully reviewed and selected from 12 submissions. They were organized in topical...

  8. Multi-channel Dual Clocks three-dimensional probability Random Multiple Access protocol for Wireless Public Bus Networks based on RTS/CTS mechanism

    Directory of Open Access Journals (Sweden)

    Zhou Sheng Jie

    2016-01-01

    Full Text Available A MAC protocol for public bus networks, called Bus MAC protocol, designed to provide high quality Internet service for bus passengers. The paper proposed a multi-channel dual clocks three-demission probability random multiple access protocol based on RTS/CTS mechanism, decreasing collisions caused by multiple access from multiple passengers. Use the RTS/CTS mechanism increases the reliability and stability of the system, reducing the collision possibility of the information packets to a certain extent, improves the channel utilization; use the multi-channel mechanism, not only enables the channel load balancing, but also solves the problem of the hidden terminal and exposed terminal. Use the dual clocks mechanism, reducing the system idle time. At last, the different selection of the three-dimensional probabilities can make the system throughput adapt to the network load which could realize the maximum of the system throughput.

  9. Dynamic computing random access memory

    Science.gov (United States)

    Traversa, F. L.; Bonani, F.; Pershin, Y. V.; Di Ventra, M.

    2014-07-01

    The present von Neumann computing paradigm involves a significant amount of information transfer between a central processing unit and memory, with concomitant limitations in the actual execution speed. However, it has been recently argued that a different form of computation, dubbed memcomputing (Di Ventra and Pershin 2013 Nat. Phys. 9 200-2) and inspired by the operation of our brain, can resolve the intrinsic limitations of present day architectures by allowing for computing and storing of information on the same physical platform. Here we show a simple and practical realization of memcomputing that utilizes easy-to-build memcapacitive systems. We name this architecture dynamic computing random access memory (DCRAM). We show that DCRAM provides massively-parallel and polymorphic digital logic, namely it allows for different logic operations with the same architecture, by varying only the control signals. In addition, by taking into account realistic parameters, its energy expenditures can be as low as a few fJ per operation. DCRAM is fully compatible with CMOS technology, can be realized with current fabrication facilities, and therefore can really serve as an alternative to the present computing technology.

  10. Probing cell activity in random access modality

    Science.gov (United States)

    Sacconi, L.; Crocini, C.; Lotti, J.; Coppini, R.; Ferrantini, C.; Tesi, C.; Yan, P.; Loew, L. M.; Cerbai, E.; Poggesi, C.; Pavone, F. S.

    2013-06-01

    We combined the advantage of an ultrafast random access microscope with novel labelling technologies to study the intra- and inter-cellular action potential propagation in neurons and cardiac myocytes with sub-millisecond time resolution. The random accesses microscopy was used in combination with a new fluorinated voltage sensitive dye with improved photostability to record membrane potential from multiple Purkinje cells with near simultaneous sampling. The RAMP system rapidly scanned between lines drawn in the membranes of neurons to perform multiplex measurements of the TPF signal. This recording was achieved by rapidly positioning the laser excitation with the AOD to sample a patch of membrane from each cell in <100 μs for recording from five cells, multiplexing permits a temporal resolution of 400 μs sufficient to capture every spike. The system is capable to record spontaneous activity over 800 ms from five neighbouring cells simultaneously, showing that spiking is not temporally correlated. The system was also used to investigate the electrical properties of tubular system (TATS) in isolated rat ventricular myocytes.

  11. Implementation of Multiple Access Techniques Applicable for Maritime Satellite Communications

    Directory of Open Access Journals (Sweden)

    Stojce Dimov Ilcev

    2013-12-01

    Full Text Available In this paper are introduced fundamentals, characteristics, advantages and disadvantages of Multiple Access (MA employed as transmission techniques in the Maritime Mobile Satellite Communications (MMSC between ships and Coast Earth Station (CES via Geostationary Earth Orbit (GEO or Not-GEO satellite constellations. In fixed satellite communication, as a rule, especially in MMSC many users are active at the same time. The problem of simultaneous communications between many single or multipoint mobile satellite users can be solved by using MA technique, such as Frequency Division Multiple Access (FDMA, Time Division Multiple Access (TDMA, Code Division Multiple Access (CDMA, Space Division Multiple Access (SDMA and Random (Packet Division Multiple Access (RDMA. Since the resources of the systems such as the transmitting power and the bandwidth are limited, it is advisable to use the channels with complete charge and to create a different MA to the channel. This generates a problem of summation and separation of signals in the transmission and reception parts, respectively. Deciding this problem consists in the development of orthogonal channels of transmission in order to divide signals from various users unambiguously on the reception part.

  12. Quantum internet using code division multiple access

    Science.gov (United States)

    Zhang, Jing; Liu, Yu-xi; Özdemir, Şahin Kaya; Wu, Re-Bing; Gao, Feifei; Wang, Xiang-Bin; Yang, Lan; Nori, Franco

    2013-01-01

    A crucial open problem inS large-scale quantum networks is how to efficiently transmit quantum data among many pairs of users via a common data-transmission medium. We propose a solution by developing a quantum code division multiple access (q-CDMA) approach in which quantum information is chaotically encoded to spread its spectral content, and then decoded via chaos synchronization to separate different sender-receiver pairs. In comparison to other existing approaches, such as frequency division multiple access (FDMA), the proposed q-CDMA can greatly increase the information rates per channel used, especially for very noisy quantum channels. PMID:23860488

  13. Wavelet based multicarrier code division multiple access ...

    African Journals Online (AJOL)

    This paper presents the study on Wavelet transform based Multicarrier Code Division Multiple Access (MC-CDMA) system for a downlink wireless channel. The performance of the system is studied for Additive White Gaussian Noise Channel (AWGN) and slowly varying multipath channels. The bit error rate (BER) versus ...

  14. Sign-compute-resolve for random access

    NARCIS (Netherlands)

    Goseling, Jasper; Stefanovic, Cedomir; Popovski, Petar

    2014-01-01

    We present an approach to random access that is based on three elements: physical-layer network coding, signature codes and tree splitting. Upon occurrence of a collision, physical-layer network coding enables the receiver to decode the sum of the information that was transmitted by the individual

  15. Random Access to Grammar-Compressed Strings

    DEFF Research Database (Denmark)

    Bille, Philip; Landau, Gad M.; Raman, Rajeev

    2011-01-01

    (n) is the inverse of the kth row of Ackermann's function. Our representations also efficiently support decompression of any substring in S: we can decompress any substring of length m in the same complexity as a single random access query and ad- ditional O(m) time. Combining these results with fast algorithms...

  16. Time division multiple access for vehicular communications

    CERN Document Server

    Omar, Hassan Aboubakr

    2014-01-01

    This brief focuses on medium access control (MAC) in vehicular ad hoc networks (VANETs), and presents VeMAC, a novel MAC scheme based on distributed time division multiple access (TDMA) for VANETs. The performance of VeMAC is evaluated via mathematical analysis and computer simulations in comparison with other existing MAC protocols, including the IEEE 802.11p standard. This brief aims at proposing TDMA as a suitable MAC scheme for VANETs, which can support the quality-of-service requirements of high priority VANET applications.

  17. Satellite multiple access systems for mobile communication

    Science.gov (United States)

    Lewis, J. L.

    1979-01-01

    This paper considers multiple access techniques for a mobile radio system which incorporates a geosynchronous orbiting satellite repeater through which mobile terminals communicate. The communication capacities of FDMA, TDMA and CDMA systems are examined for a 4 MHz bandwidth system to serve up to 10,000 users. An FDMA system with multibeam coverage is analyzed in detail. The system includes an order-wire network for demand-access control and reassignment of satellite channels. Satellite and terminal configurations are developed to a block diagram level and system costs and implementation requirements are discussed.

  18. Sign Compute Resolve for Random Access

    DEFF Research Database (Denmark)

    Goseling, Jasper; Stefanovic, Cedomir; Popovski, Petar

    2014-01-01

    We present an approach to random access that is based on three elements: physical-layer network coding, signature codes and tree splitting. Upon occurrence of a collision, physical-layer network coding enables the receiver to decode the sum of the information that was transmitted by the individual...... users. For each user this information consists of the data that the user wants to communicate as well as the user's signature. As long as no more than K users collide, their identities can be recovered from the sum of their signatures. A splitting protocol is used to deal with the case that more than K...... users collide. We measure the performance of the proposed method in terms of user resolution rate as well as overall throughput of the system. The results show that our approach significantly increases the performance of the system even compared to coded random access, where collisions are not wasted...

  19. Quantum optics in multiple scattering random media

    DEFF Research Database (Denmark)

    Lodahl, Peter

    Quantum Optics in Multiple Scattering Random Media Peter Lodahl Research Center COM, Technical University of Denmark, Dk-2800 Lyngby, Denmark. Coherent transport of light in a disordered random medium has attracted enormous attention both from a fundamental and application point of view. Coherent...... quantum optics in multiple scattering media and novel fundamental phenomena have been predicted when examining quantum fluctuations instead of merely the intensity of the light [1]. Here I will present the first experimental study of the propagation of quantum noise through an elastic, multiple scattering...

  20. Cooperation evolution in random multiplicative environments

    Science.gov (United States)

    Yaari, G.; Solomon, S.

    2010-02-01

    Most real life systems have a random component: the multitude of endogenous and exogenous factors influencing them result in stochastic fluctuations of the parameters determining their dynamics. These empirical systems are in many cases subject to noise of multiplicative nature. The special properties of multiplicative noise as opposed to additive noise have been noticed for a long while. Even though apparently and formally the difference between free additive vs. multiplicative random walks consists in just a move from normal to log-normal distributions, in practice the implications are much more far reaching. While in an additive context the emergence and survival of cooperation requires special conditions (especially some level of reward, punishment, reciprocity), we find that in the multiplicative random context the emergence of cooperation is much more natural and effective. We study the various implications of this observation and its applications in various contexts.

  1. Accessibility and delay in random temporal networks

    Science.gov (United States)

    Tajbakhsh, Shahriar Etemadi; Coon, Justin P.; Simmons, David E.

    2017-09-01

    In a wide range of complex networks, the links between the nodes are temporal and may sporadically appear and disappear. This temporality is fundamental to analyzing the formation of paths within such networks. Moreover, the presence of the links between the nodes is a random process induced by nature in many real-world networks. In this paper, we study random temporal networks at a microscopic level and formulate the probability of accessibility from a node i to a node j after a certain number of discrete time units T . While solving the original problem is computationally intractable, we provide an upper and two lower bounds on this probability for a very general case with arbitrary time-varying probabilities of the links' existence. Moreover, for a special case where the links have identical probabilities across the network at each time slot, we obtain the exact probability of accessibility between any two nodes. Finally, we discuss scenarios where the information regarding the presence and absence of links is initially available in the form of time duration (of presence or absence intervals) continuous probability distributions rather than discrete probabilities over time slots. We provide a method for transforming such distributions to discrete probabilities, which enables us to apply the given bounds in this paper to a broader range of problem settings.

  2. Stability Properties of Network Diversity Multiple Access with Multiple-Antenna Reception and Imperfect Collision Multiplicity Estimation

    Directory of Open Access Journals (Sweden)

    Ramiro Samano-Robles

    2013-01-01

    Full Text Available In NDMA (network diversity multiple access, protocol-controlled retransmissions are used to create a virtual MIMO (multiple-input multiple-output system, where collisions can be resolved via source separation. By using this retransmission diversity approach for collision resolution, NDMA is the family of random access protocols with the highest potential throughput. However, several issues remain open today in the modeling and design of this type of protocol, particularly in terms of dynamic stable performance and backlog delay. This paper attempts to partially fill this gap by proposing a Markov model for the study of the dynamic-stable performance of a symmetrical and non-blind NDMA protocol assisted by a multiple-antenna receiver. The model is useful in the study of stability aspects in terms of the backlog-user distribution and average backlog delay. It also allows for the investigation of the different states of the system and the transition probabilities between them. Unlike previous works, the proposed approach considers the imperfect estimation of the collision multiplicity, which is a crucial process to the performance of NDMA. The results suggest that NDMA improves not only the throughput performance over previous solutions, but also the average number of backlogged users, the average backlog delay and, in general, the stability of random access protocols. It is also shown that when multiuser detection conditions degrade, ALOHA-type backlog retransmission becomes relevant to the stable operation of NDMA.

  3. Introduction to magnetic random-access memory

    CERN Document Server

    Dieny, Bernard; Lee, Kyung-Jin

    2017-01-01

    Magnetic random-access memory (MRAM) is poised to replace traditional computer memory based on complementary metal-oxide semiconductors (CMOS). MRAM will surpass all other types of memory devices in terms of nonvolatility, low energy dissipation, fast switching speed, radiation hardness, and durability. Although toggle-MRAM is currently a commercial product, it is clear that future developments in MRAM will be based on spin-transfer torque, which makes use of electrons’ spin angular momentum instead of their charge. MRAM will require an amalgamation of magnetics and microelectronics technologies. However, researchers and developers in magnetics and in microelectronics attend different technical conferences, publish in different journals, use different tools, and have different backgrounds in condensed-matter physics, electrical engineering, and materials science. This book is an introduction to MRAM for microelectronics engineers written by specialists in magnetic mat rials and devices. It presents the bas...

  4. ASSISTments Dataset from Multiple Randomized Controlled Experiments

    Science.gov (United States)

    Selent, Douglas; Patikorn, Thanaporn; Heffernan, Neil

    2016-01-01

    In this paper, we present a dataset consisting of data generated from 22 previously and currently running randomized controlled experiments inside the ASSISTments online learning platform. This dataset provides data mining opportunities for researchers to analyze ASSISTments data in a convenient format across multiple experiments at the same time.…

  5. Improved classical and quantum random access codes

    Science.gov (United States)

    Liabøtrø, O.

    2017-05-01

    A (quantum) random access code ((Q)RAC) is a scheme that encodes n bits into m (qu)bits such that any of the n bits can be recovered with a worst case probability p >1/2 . We generalize (Q)RACs to a scheme encoding n d -levels into m (quantum) d -levels such that any d -level can be recovered with the probability for every wrong outcome value being less than 1/d . We construct explicit solutions for all n ≤d/2m-1 d -1 . For d =2 , the constructions coincide with those previously known. We show that the (Q)RACs are d -parity oblivious, generalizing ordinary parity obliviousness. We further investigate optimization of the success probabilities. For d =2 , we use the measure operators of the previously best-known solutions, but improve the encoding states to give a higher success probability. We conjecture that for maximal (n =4m-1 ,m ,p ) QRACs, p =1/2 {1 +[(√{3}+1)m-1 ] -1} is possible, and show that it is an upper bound for the measure operators that we use. We then compare (n ,m ,pq) QRACs with classical (n ,2 m ,pc) RACs. We can always find pq≥pc , but the classical code gives information about every input bit simultaneously, while the QRAC only gives information about a subset. For several different (n ,2 ,p ) QRACs, we see the same trade-off, as the best p values are obtained when the number of bits that can be obtained simultaneously is as small as possible. The trade-off is connected to parity obliviousness, since high certainty information about several bits can be used to calculate probabilities for parities of subsets.

  6. Code-Expanded Random Access for Machine-Type Communications

    DEFF Research Database (Denmark)

    Kiilerich Pratas, Nuno; Thomsen, Henning; Stefanovic, Cedomir

    2012-01-01

    Abstract—The random access methods used for support of machine-type communications (MTC) in current cellular standards are derivatives of traditional framed slotted ALOHA and therefore do not support high user loads efficiently. Motivated by the random access method employed in LTE, we propose...

  7. Multiple Hemodialysis Access Failures Due to Recurrent ...

    African Journals Online (AJOL)

    Introduction: The most common complication of permanent hemodialysis (HD) vascular access is thrombosis, with some cases being related to a hypercoagulable state. Antiphospholipid antibody syndrome (APAS) is a cause of increased thrombotic tendency, and this may complicate the management of such patients on ...

  8. Mission-Aware Medium Access Control in Random Access Networks

    OpenAIRE

    Park, Jaeok; Van Der Schaar, Mihaela

    2009-01-01

    We study mission-critical networking in wireless communication networks, where network users are subject to critical events such as emergencies and crises. If a critical event occurs to a user, the user needs to send necessary information for help as early as possible. However, most existing medium access control (MAC) protocols are not adequate to meet the urgent need for information transmission by users in a critical situation. In this paer, we propose a novel class of MAC protocols that u...

  9. RACBVHs: random-accessible compressed bounding volume hierarchies.

    Science.gov (United States)

    Kim, Tae-Joon; Moon, Bochang; Kim, Duksu; Yoon, Sung-Eui

    2010-01-01

    We present a novel compressed bounding volume hierarchy (BVH) representation, random-accessible compressed bounding volume hierarchies (RACBVHs), for various applications requiring random access on BVHs of massive models. Our RACBVH representation is compact and transparently supports random access on the compressed BVHs without decompressing the whole BVH. To support random access on our compressed BVHs, we decompose a BVH into a set of clusters. Each cluster contains consecutive bounding volume (BV) nodes in the original layout of the BVH. Also, each cluster is compressed separately from other clusters and serves as an access point to the RACBVH representation. We provide the general BVH access API to transparently access our RACBVH representation. At runtime, our decompression framework is guaranteed to provide correct BV nodes without decompressing the whole BVH. Also, our method is extended to support parallel random access that can utilize the multicore CPU architecture. Our method can achieve up to a 12:1 compression ratio, and more importantly, can decompress 4.2 M BV nodes ({=}135 {\\rm MB}) per second by using a single CPU-core. To highlight the benefits of our approach, we apply our method to two different applications: ray tracing and collision detection. We can improve the runtime performance by more than a factor of 4 as compared to using the uncompressed original data. This improvement is a result of the fast decompression performance and reduced data access time by selectively fetching and decompressing small regions of the compressed BVHs requested by applications.

  10. Enhancing the Performance of Random Access Networks with Random Packet CDMA and Joint Detection

    Directory of Open Access Journals (Sweden)

    Behrouz Farhang-Boroujeny

    2008-09-01

    Full Text Available Random packet CDMA (RP-CDMA is a recently proposed random transmission scheme which has been designed from the beginning as a cross-layer method to overcome the restrictive nature of the Aloha protocol. Herein, we more precisely model its performance and investigate throughput and network stability. In contrast to previous works, we adopt the spread Aloha model for header transmission, and the performance of different joint detection methods for the payload data is investigated. Furthermore, we introduce performance measures for multiple access systems based on the diagonal elements of a modified multipacket reception matrix, and show that our measures describe the upper limit of the vector of stable arrival rates for a finite number of users. Finally, we simulate queue sizes and throughput characteristics of RP-CDMA with various receiver structures and compare them to spread Aloha.

  11. Enhancing the Performance of Random Access Networks with Random Packet CDMA and Joint Detection

    Science.gov (United States)

    Kempter, Roland; Amini, Peiman; Farhang-Boroujeny, Behrouz

    2008-12-01

    Random packet CDMA (RP-CDMA) is a recently proposed random transmission scheme which has been designed from the beginning as a cross-layer method to overcome the restrictive nature of the Aloha protocol. Herein, we more precisely model its performance and investigate throughput and network stability. In contrast to previous works, we adopt the spread Aloha model for header transmission, and the performance of different joint detection methods for the payload data is investigated. Furthermore, we introduce performance measures for multiple access systems based on the diagonal elements of a modified multipacket reception matrix, and show that our measures describe the upper limit of the vector of stable arrival rates for a finite number of users. Finally, we simulate queue sizes and throughput characteristics of RP-CDMA with various receiver structures and compare them to spread Aloha.

  12. Advanced multiple access concepts in mobile satellite systems

    Science.gov (United States)

    Ananasso, Fulvio

    1990-01-01

    Some multiple access strategies for Mobile Satellite Systems (MSS) are discussed. These strategies were investigated in the context of three separate studies conducted for the International Maritime Satellite Organization (INMARSAT) and the European Space Agency (ESA). Satellite-Switched Frequency Division Multiple Access (SS-FDMA), Code Division Multiple Access (CDMA), and Frequency-Addressable Beam architectures are addressed, discussing both system and technology aspects and outlining advantages and drawbacks of either solution with associated relevant hardware issues. An attempt is made to compare the considered option from the standpoint of user terminal/space segment complexity, synchronization requirements, spectral efficiency, and interference rejection.

  13. Instruction Sets for Parallel Random Access Machines

    Science.gov (United States)

    1988-08-01

    tapes, Q’ uses multiple tracks, one per tape of Q, Suppose Q’ is in a right sweep; that is, Q’ is in a state O"Q e R. The case where Q’ is in a left... multiplication block for reasons of MRAM -uniformity. Insert carry-save multiplication blocks in BCn’. Each block has depth 0 (T(n)) and size 0 (n24T(n)). Thus, BC...Science Lab (f 4APk&W*) University of Illinois N/A Office of Naval Research 6c. ADDRESS (City, State , and ZIP Code) 7b. ADDRESS (City, State , and ZIP

  14. Spin Injection in Thermally Assisted Magnetic Random Access Memory

    National Research Council Canada - National Science Library

    Deak, James G

    2005-01-01

    An integrated thermal, micromagnetic, spin-momentum-transfer (SMT) model was developed to study the effect of SMT on the programming current required for thermally assisted magnetic random access memory (MRAM...

  15. A novel root-index based prioritized random access scheme for 5G cellular networks

    Directory of Open Access Journals (Sweden)

    Taehoon Kim

    2015-12-01

    Full Text Available Cellular networks will play an important role in realizing the newly emerging Internet-of-Everything (IoE. One of the challenging issues is to support the quality of service (QoS during the access phase, while accommodating a massive number of machine nodes. In this paper, we show a new paradigm of multiple access priorities in random access (RA procedure and propose a novel root-index based prioritized random access (RIPRA scheme that implicitly embeds the access priority in the root index of the RA preambles. The performance evaluation shows that the proposed RIPRA scheme can successfully support differentiated performance for different access priority levels, even though there exist a massive number of machine nodes.

  16. Average Likelihood Methods for Code Division Multiple Access (CDMA)

    Science.gov (United States)

    2014-05-01

    AVERAGE LIKELIHOOD METHODS FOR CODE DIVISION MULTIPLE ACCESS ( CDMA ) MAY 2014 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC RELEASE; DISTRIBUTION...REPORT 3. DATES COVERED (From - To) OCT 2011 – OCT 2013 4. TITLE AND SUBTITLE AVERAGE LIKELIHOOD METHODS FOR CODE DIVISION MULTIPLE ACCESS ( CDMA ) 5a...precision parameter from the joint probability of the code matrix. For a full loaded CDMA signal, the average likelihood depends exclusively on feature

  17. Orthogonal frequency division multiple access fundamentals and applications

    CERN Document Server

    Jiang, Tao; Zhang, Yan

    2010-01-01

    Supported by the expert-level advice of pioneering researchers, Orthogonal Frequency Division Multiple Access Fundamentals and Applications provides a comprehensive and accessible introduction to the foundations and applications of one of the most promising access technologies for current and future wireless networks. It includes authoritative coverage of the history, fundamental principles, key techniques, and critical design issues of OFDM systems. Covering various techniques of effective resource management for OFDM/OFDMA-based wireless communication systems, this cutting-edge reference:Add

  18. Random access with adaptive packet aggregation in LTE/LTE-A.

    Science.gov (United States)

    Zhou, Kaijie; Nikaein, Navid

    While random access presents a promising solution for efficient uplink channel access, the preamble collision rate can significantly increase when massive number of devices simultaneously access the channel. To address this issue and improve the reliability of the random access, an adaptive packet aggregation method is proposed. With the proposed method, a device does not trigger a random access for every single packet. Instead, it starts a random access when the number of aggregated packets reaches a given threshold. This method reduces the packet collision rate at the expense of an extra latency, which is used to accumulate multiple packets into a single transmission unit. Therefore, the tradeoff between packet loss rate and channel access latency has to be carefully selected. We use semi-Markov model to derive the packet loss rate and channel access latency as functions of packet aggregation number. Hence, the optimal amount of aggregated packets can be found, which keeps the loss rate below the desired value while minimizing the access latency. We also apply for the idea of packet aggregation for power saving, where a device aggregates as many packets as possible until the latency constraint is reached. Simulations are carried out to evaluate our methods. We find that the packet loss rate and/or power consumption are significantly reduced with the proposed method.

  19. ALOHA Random Access that Operates as a Rateless Code

    DEFF Research Database (Denmark)

    Stefanovic, Cedomir; Popovski, Petar

    2013-01-01

    Various applications of wireless Machine-to-Machine (M2M) communications have rekindled the research interest in random access protocols, suitable to support a large number of connected devices. Slotted ALOHA and its derivatives represent a simple solution for distributed random access in wireless...... networks. Recently, a framed version of slotted ALOHA gained renewed interest due to the incorporation of successive interference cancellation (SIC) in the scheme, which resulted in substantially higher throughputs. Based on similar principles and inspired by the rateless coding paradigm, a frameless...... approach for distributed random access in the slotted ALOHA framework is described in this paper. The proposed approach shares an operational analogy with rateless coding, expressed both through the user access strategy and the adaptive length of the contention period, with the objective to end...

  20. Randomized distributed access to mutually exclusive resources

    Directory of Open Access Journals (Sweden)

    Moshe Dror

    2005-01-01

    they generally suffer from the need for extensive interagent communication. In this paper, we develop a randomized approach to make multiagent resource-allocation decisions with the objective of maximizing expected concurrency measured by the number of the active agents. This approach does not assume a centralized mechanism and has no need for interagent communication. Compared to existing autonomous-decentralized-decision-making (ADDM-based approaches for resource-allocation, our work emphasizes achieving the highest degree of agent autonomy and is able to handle more general resource requirements.

  1. Functional cardiac imaging by random access microscopy

    Directory of Open Access Journals (Sweden)

    Claudia eCrocini

    2014-10-01

    Full Text Available Advances in the development of voltage sensitive dyes and Ca2+ sensors in combination with innovative microscopy techniques allowed researchers to perform functional measurements with an unprecedented spatial and temporal resolution. At the moment, one of the shortcomings of available technologies is their incapability of imaging multiple fast phenomena while controlling the biological determinants involved. In the near future, ultrafast deflectors can be used to rapidly scan laser beams across the sample, performing optical measurements of action potential and Ca2+ release from multiple sites within cardiac cells and tissues. The same scanning modality could also be used to control local Ca2+ release and membrane electrical activity by activation of caged compounds and light-gated ion channels. With this approach, local Ca2+ or voltage perturbations could be induced, simulating arrhythmogenic events, and their impact on physiological cell activity could be explored. The development of this optical methodology will provide fundamental insights in cardiac disease, boosting new therapeutic strategies, and, more generally, it will represent a new approach for the investigation of the physiology of excitable cells.

  2. Non-orthogonal multiple access for 5G and beyond

    OpenAIRE

    Liu, Yuanwei; Qin, Zhijin; Elkashlan, Maged; Ding, Zhiguo; Nallanathan, Arumugam; Hanzo, Lajos

    2017-01-01

    Driven by the rapid escalation of the wireless capacity requirements imposed by advanced multimedia applications (e.g., ultrahigh-definition video, virtual reality, etc.), as well as the dramatically increasing demand for user access required for the Internet of Things (IoT), the fifth-generation (5G) networks face challenges in terms of supporting large-scale heterogeneous data traffic. Nonorthogonal multiple access (NOMA), which has been recently proposed for the third-generation partnershi...

  3. Simulation of parallel random access machines by circuits

    Energy Technology Data Exchange (ETDEWEB)

    Stockmeyer, L.; Vishkin, U.

    1984-05-01

    A relationship is established between (i) parallel random-access machines that allow many processors to concurrently read from or write into a common memory including simultaneous reading or writing into the same memory location (CRCW PRAM), and (ii) combinational logic circuits that contain AND's, OR's and NOT's, with no bound placed on the fan-in of AND-gates and OR-gates. Parallel time and number of processors for CRCW PRAM's are shown to correspond respectively (and simulaneously) to depth and size for circuits, where the time-depth correspondence is to within a constant factor and the processors-size correspondence is to within a polynomial. By applying a recent result of Furst, Saxe and Sipser, the authors obtain the corollary that parity, integer multiplication, graph transitive closure and integer sorting cannot be computed in constant time by a CRCW PRAM with a polynomial number of processors. This is the first nonconstant lower bound on the parallel time required to solve these problems by a CRCW PRAM with a polynomial number of processors. The authors also state and outline the proof of a similar result, due to W. L. Ruzzo and M. Tompa, that relates time and processor bounds for CRCW PRAM's to alternation and space bounds for alternating Turing machines.

  4. On Buffer-Aided Multiple-Access Relay Channel

    DEFF Research Database (Denmark)

    Liu, Rongkuan; Popovski, Petar; Wang, Gang

    2016-01-01

    This letter treats uplink scenario where M user equipments (UEs) send to a base station (BS), possibly via a common relay station (RS) that is equipped with a buffer. This is a multiple-access relay channel aided by a buffer. We devise a protocol in which the transmission mode is selected...... adaptively, using the buffer at the RS in order to maximize the average system throughput. We consider the general case in which the RS and the BS can have limits on the maximal number of transmitters that can be received over the multiple access channel. In each slot, there are three type possible actions...

  5. Optical code division multiple access fundamentals and applications

    CERN Document Server

    Prucnal, Paul R

    2005-01-01

    Code-division multiple access (CDMA) technology has been widely adopted in cell phones. Its astonishing success has led many to evaluate the promise of this technology for optical networks. This field has come to be known as Optical CDMA (OCDMA). Surveying the field from its infancy to the current state, Optical Code Division Multiple Access: Fundamentals and Applications offers the first comprehensive treatment of OCDMA from technology to systems.The book opens with a historical perspective, demonstrating the growth and development of the technologies that would eventually evolve into today's

  6. Radio Access Sharing Strategies for Multiple Operators in Cellular Networks

    DEFF Research Database (Denmark)

    Popovska Avramova, Andrijana; Iversen, Villy Bæk

    2015-01-01

    deployments (required for coverage enhancement), increased base station utilization, and reduced overall power consumption. Today, network sharing in the radio access part is passive and limited to cell sites. With the introduction of Cloud Radio Access Network and Software Defined Networking adoption......Mobile operators are moving towards sharing network capacity in order to reduce capital and operational expenditures, while meeting the increasing demand for mobile broadband data services. Radio access network sharing is a promising technique that leads to reduced number of physical base station...... to the radio access network, the possibility for sharing baseband processing and radio spectrum becomes an important aspect of network sharing. This paper investigates strategies for active sharing of radio access among multiple operators, and analyses the individual benefits depending on the sharing degree...

  7. First principles modeling of magnetic random access memory devices (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Butler, W.H.; Zhang, X.; Schulthess, T.C.; Nicholson, D.M.; Oparin, A.B. [Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); MacLaren, J.M. [Department of Physics, Tulane University, New Orleans, Louisiana 70018 (United States)

    1999-04-01

    Giant magnetoresistance (GMR) and spin-dependent tunneling may be used to make magnetic random access memory devices. We have applied first-principles based electronic structure techniques to understand these effects and in the case of GMR to model the transport properties of the devices. {copyright} {ital 1999 American Institute of Physics.}

  8. Random Access with Physical-layer Network Coding

    NARCIS (Netherlands)

    Goseling, J.; Gastpar, M.C.; Weber, J.H.

    2013-01-01

    Leveraging recent progress in compute-and-forward we propose an approach to random access that is based on physical-layer network coding: When packets collide, it is possible to recover a linear combination of the packets at the receiver. Over many rounds of transmission, the receiver can thus

  9. Web-based secure access from multiple patient repositories.

    Science.gov (United States)

    Choe, Jun; Yoo, Sun K

    2008-04-01

    Internet-based health-record management requires not only the provision of strong data protection to prevent privacy intrusion and unauthorized access, but also the introduction of a common healthcare-record format to allow cooperation using heterogeneous repositories held at various hospitals. A secure multi-agent architecture is proposed for accessing healthcare information through the Internet from multiple heterogeneous repositories. The proposed system is organized into a four-tier architecture that consists of client applications, a central access-control system, local access-control systems, and hospital information systems. The eXtensible Markup Language (XML) and the role-based access-control (RBAC) system are combined for efficient repository management by providing methods for access-control, information exchange, user authentication, data integrity, and selective encryption. A multi-agent architecture using XML and RBAC can interconnect heterogeneous repositories with different formats and different hospital policies, and allow them to communicate securely. The authorized client, having confirmed access privileges, can retrieve the requested healthcare data in an XML-based common data format with embedded confidentiality. The proposed method for Internet-based exchange of patient data is particularly useful for cooperative healthcare and the creation of lifetime healthcare records.

  10. Frame-Based Random Access with Interference Cancellation across Frames for Massive Machine Type Communications

    Directory of Open Access Journals (Sweden)

    Minjoong Rim

    2017-01-01

    Full Text Available One of the main requirements for next generation mobile or wireless communication systems is to effectively support a large number of machine type communication devices for Internet of things applications. In order to improve the random access capability in frame-based slotted Aloha environments, coded random access techniques have been proposed, in which multiple copies of a packet are transmitted per frame and the copies are cancelled out from the received signal if any single copy is successfully received. They, however, may increase the transmission power by sending multiple copies per frame. Above all, for systems with a small number of slots per frame, they may not be able to improve the performance by readily reaching a congested state. This paper proposes a new frame-based random access scheme, which sends at most one copy of a packet per frame but uses interference cancellation to improve the performance. If a successfully received packet is a retransmitted one, the previously transmitted signals for the packet can be cancelled out from the received signals for trying to decode other received packets. The proposed scheme has different characteristics than coded random access schemes and can be also combined with them to further improve the performance.

  11. Mobile access to virtual randomization for investigator-initiated trials.

    Science.gov (United States)

    Deserno, Thomas M; Keszei, András P

    2017-08-01

    Background/aims Randomization is indispensable in clinical trials in order to provide unbiased treatment allocation and a valid statistical inference. Improper handling of allocation lists can be avoided using central systems, for example, human-based services. However, central systems are unaffordable for investigator-initiated trials and might be inaccessible from some places, where study subjects need allocations. We propose mobile access to virtual randomization, where the randomization lists are non-existent and the appropriate allocation is computed on demand. Methods The core of the system architecture is an electronic data capture system or a clinical trial management system, which is extended by an R interface connecting the R server using the Java R Interface. Mobile devices communicate via the representational state transfer web services. Furthermore, a simple web-based setup allows configuring the appropriate statistics by non-statisticians. Our comprehensive R script supports simple randomization, restricted randomization using a random allocation rule, block randomization, and stratified randomization for un-blinded, single-blinded, and double-blinded trials. For each trial, the electronic data capture system or the clinical trial management system stores the randomization parameters and the subject assignments. Results Apps are provided for iOS and Android and subjects are randomized using smartphones. After logging onto the system, the user selects the trial and the subject, and the allocation number and treatment arm are displayed instantaneously and stored in the core system. So far, 156 subjects have been allocated from mobile devices serving five investigator-initiated trials. Conclusion Transforming pre-printed allocation lists into virtual ones ensures the correct conduct of trials and guarantees a strictly sequential processing in all trial sites. Covering 88% of all randomization models that are used in recent trials, virtual randomization

  12. Alternative multiple-access techniques for mobile satellite systems

    Science.gov (United States)

    Smith, Patrick O.; Geraniotis, Evaggelos

    1989-01-01

    The use of Code Division Multiple Access (CDMA) to satisfy the diverse requirements of a generic (land, maritime, aeronautical) mobile satellite system (MSS) network design is discussed. Comparisons between CDMA and Frequency Division Multiple Access (FDMA) show that a CDMA network design can support significantly more voice channel allocations than FDMA when relatively simple CDMA correlation receivers are employed, provided that there is sufficient space segment equivalent isotropically radiated power (EIRP). The use of more advanced CDMA receivers can improve the spectral and power efficiency. Although the use of CDMA may not gain immediate and widespread support in the international MSS community, provision for the use of CDMA for a domestic system in the U.S., and possibly for a regional system throughout North America, is likely.

  13. Code division multiple access signaling for modulated reflector technology

    Science.gov (United States)

    Briles, Scott D [Los Alamos, NM

    2012-05-01

    A method and apparatus for utilizing code division multiple access in modulated reflectance transmissions comprises the steps of generating a phase-modulated reflectance data bit stream; modifying the modulated reflectance data bit stream; providing the modified modulated reflectance data bit stream to a switch that connects an antenna to an infinite impedance in the event a "+1" is to be sent, or connects the antenna to ground in the event a "0" or a "-1" is to be sent.

  14. Multiple Access Channels with States Causally Known at Transmitters

    OpenAIRE

    Li, Min; Simeone, Osvaldo; Yener, Aylin

    2010-01-01

    It has been recently shown by Lapidoth and Steinberg that strictly causal state information can be beneficial in multiple access channels (MACs). Specifically, it was proved that the capacity region of a two-user MAC with independent states, each known strictly causally to one encoder, can be enlarged by letting the encoders send compressed past state information to the decoder. In this work, a generalization of the said strategy is proposed whereby the encoders compress also the past transmi...

  15. Quantum optics in multiple scattering random media

    NARCIS (Netherlands)

    Lodahl, P.; Lagendijk, Aart

    2005-01-01

    The paper presents the first experimental study of the propagation of quantum noise through an elastic, multiple scattering medium. Two different types of quantum noise measurements have been carried out: total transmission and short-range frequency correlations. When comparing shot noise (quantum)

  16. Multiple-Access Technology of Choice In 3GPP LTE

    Directory of Open Access Journals (Sweden)

    Ibikunle Frank

    2013-09-01

    Full Text Available Third-Generation Partnership Project (3GPP standardizes an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN as air interface in its release 8 LTE. Orthogonal Frequency Division Multiple Access(OFDMA and Single Carrier-Frequency Division Multiple Access(SC-FDMAare key technologies for the air interface of mobile broadband systems.It is evident that mobile broadband access technologies are reaching a commonality in the air interface and networking architecture; they are being converged to an IP-based network architecture with OFDMA based air interface technology. The air interface of E-UTRAN is based on OFDMA in downlink and SC-FDMA in the uplink, making it possible to efficiently utilize bandwidth due to the orthogonally between sub-carriers and by assigning subsets of sub-carriers to individual users which allows for simultaneous data rate transmission from several users and differentiated quality of service for each user. In this paper, wehighlight the technologies behindOFDMA and SC-FDMA and also carry out performance comparison of the two air interface technologies. We brieflydescribe the 3GPP LTE standard, and its implementation using OFDMA and SC-FDMA technology.

  17. Random access quantum information processors using multimode circuit quantum electrodynamics.

    Science.gov (United States)

    Naik, R K; Leung, N; Chakram, S; Groszkowski, Peter; Lu, Y; Earnest, N; McKay, D C; Koch, Jens; Schuster, D I

    2017-12-04

    Qubit connectivity is an important property of a quantum processor, with an ideal processor having random access-the ability of arbitrary qubit pairs to interact directly. This a challenge with superconducting circuits, as state-of-the-art architectures rely on only nearest-neighbor coupling. Here, we implement a random access superconducting quantum information processor, demonstrating universal operations on a nine-qubit memory, with a Josephson junction transmon circuit serving as the central processor. The quantum memory uses the eigenmodes of a linear array of coupled superconducting resonators. We selectively stimulate vacuum Rabi oscillations between the transmon and individual eigenmodes through parametric flux modulation of the transmon frequency. Utilizing these oscillations, we perform a universal set of quantum gates on 38 arbitrary pairs of modes and prepare multimode entangled states, all using only two control lines. We thus achieve hardware-efficient random access multi-qubit control in an architecture compatible with long-lived microwave cavity-based quantum memories.

  18. Hierarchical Slotted Wireless Random Channel Access with Power Control

    Directory of Open Access Journals (Sweden)

    Abdelillah Karouit

    2015-01-01

    Full Text Available This paper introduces a hierarchical Wireless Random Access scheme based on power control where intelligence is split among the mobile users in order to drive the outcome of the system towards an efficient point. The hierarchical game is obtained by introducing a special user who plays the role of altruistic leader whereas the other users assume the role of followers. We define the power control scheme in such a way that the leader_first chooses the lowest power to transmit its packets among N available levels whereas the followers re-transmit by randomly choosing a power level picked from N-1 higher distinct power levels. Using a 3D Markovian model, we compute the steady state of the system and derive the average system throughput and expected packet transmission delay. Our numerical results show that the proposed scheme considerably improves the global performance of the system avoiding the well known throughput collapse at high loads commonly characterizing most random channel access mechanisms.

  19. Adaptive Information Access in Multiple Applications Support Wireless Sensor Network

    DEFF Research Database (Denmark)

    Tobgay, Sonam; Olsen, Rasmus Løvenstein; Prasad, Ramjee

    2012-01-01

    set of requirements. Lastly, the paper suggests a mechanism by which the information access or acquisition can be adapted as per the requirements of the application. The main parameters focused in this paper are mismatch probability [1] and power dissipation with respect to sampling rate....... specific WSN considering its resource constraints, neglecting the return-of-investment and usefulness of the system. In this paper, we bring out the WSN scenario which supports multiple applications and study the challenges that would pose in implementation as each specific application has its own specific...

  20. Non-Orthogonal Multiple Access for Ubiquitous Wireless Sensor Networks.

    Science.gov (United States)

    Anwar, Asim; Seet, Boon-Chong; Ding, Zhiguo

    2018-02-08

    Ubiquitous wireless sensor networks (UWSNs) have become a critical technology for enabling smart cities and other ubiquitous monitoring applications. Their deployment, however, can be seriously hampered by the spectrum available to the sheer number of sensors for communication. To support the communication needs of UWSNs without requiring more spectrum resources, the power-domain non-orthogonal multiple access (NOMA) technique originally proposed for 5th Generation (5G) cellular networks is investigated for UWSNs for the first time in this paper. However, unlike 5G networks that operate in the licensed spectrum, UWSNs mostly operate in unlicensed spectrum where sensors also experience cross-technology interferences from other devices sharing the same spectrum. In this paper, we model the interferences from various sources at the sensors using stochastic geometry framework. To evaluate the performance, we derive a theorem and present new closed form expression for the outage probability of the sensors in a downlink scenario under interference limited environment. In addition, diversity analysis for the ordered NOMA users is performed. Based on the derived outage probability, we evaluate the average link throughput and energy consumption efficiency of NOMA against conventional orthogonal multiple access (OMA) technique in UWSNs. Further, the required computational complexity for the NOMA users is presented.

  1. An optimal probabilistic multiple-access scheme for cognitive radios

    KAUST Repository

    Hamza, Doha R.

    2012-09-01

    We study a time-slotted multiple-access system with a primary user (PU) and a secondary user (SU) sharing the same channel resource. The SU senses the channel at the beginning of the slot. If found free, it transmits with probability 1. If busy, it transmits with a certain access probability that is a function of its queue length and whether it has a new packet arrival. Both users, i.e., the PU and the SU, transmit with a fixed transmission rate by employing a truncated channel inversion power control scheme. We consider the case of erroneous sensing. The goal of the SU is to optimize its transmission scheduling policy to minimize its queueing delay under constraints on its average transmit power and the maximum tolerable primary outage probability caused by the miss detection of the PU. We consider two schemes regarding the secondary\\'s reaction to transmission errors. Under the so-called delay-sensitive (DS) scheme, the packet received in error is removed from the queue to minimize delay, whereas under the delay-tolerant (DT) scheme, the said packet is kept in the buffer and is retransmitted until correct reception. Using the latter scheme, there is a probability of buffer loss that is also constrained to be lower than a certain specified value. We also consider the case when the PU maintains an infinite buffer to store its packets. In the latter case, we modify the SU access scheme to guarantee the stability of the PU queue. We show that the performance significantly changes if the realistic situation of a primary queue is considered. In all cases, although the delay minimization problem is nonconvex, we show that the access policies can be efficiently obtained using linear programming and grid search over one or two parameters. © 1967-2012 IEEE.

  2. Embedded Memory Hierarchy Exploration Based on Magnetic Random Access Memory

    Directory of Open Access Journals (Sweden)

    Luís Vitório Cargnini

    2014-08-01

    Full Text Available Static random access memory (SRAM is the most commonly employed semiconductor in the design of on-chip processor memory. However, it is unlikely that the SRAM technology will have a cell size that will continue to scale below 45 nm, due to the leakage current that is caused by the quantum tunneling effect. Magnetic random access memory (MRAM is a candidate technology to replace SRAM, assuming appropriate dimensioning given an operating threshold voltage. The write current of spin transfer torque (STT-MRAM is a known limitation; however, this has been recently mitigated by leveraging perpendicular magnetic tunneling junctions. In this article, we present a comprehensive comparison of spin transfer torque-MRAM (STT-MRAM and SRAM cache set banks. The non-volatility of STT-MRAM allows the definition of new instant on/off policies and leakage current optimizations. Through our experiments, we demonstrate that STT-MRAM is a candidate for the memory hierarchy of embedded systems, due to the higher densities and reduced leakage of MRAM.We demonstrate that adopting STT-MRAM in L1 and L2 caches mitigates the impact of higher write latencies and increased current draw due to the use of MRAM. With the correct system-on-chip (SoC design, we believe that STT-MRAM is a viable alternative to SRAM, which minimizes leakage current and the total power consumed by the SoC.

  3. Prediction of mechanical fatigue caused by multiple random excitations

    NARCIS (Netherlands)

    Bonte, M.H.A.; de Boer, Andries; Liebregts, R.

    2004-01-01

    A simulation method is presented for the fatigue analysis of automotive and other products that are subjected to multiple random excitations. The method is denoted as frequency domain stress-life fatigue analysis and was implemented in the automotive industry at DAF Trucks N.V. in Eindhoven, The

  4. Non-stationary random vibration analysis of structures under multiple correlated normal random excitations

    Science.gov (United States)

    Li, Yanbin; Mulani, Sameer B.; Kapania, Rakesh K.; Fei, Qingguo; Wu, Shaoqing

    2017-07-01

    An algorithm that integrates Karhunen-Loeve expansion (KLE) and the finite element method (FEM) is proposed to perform non-stationary random vibration analysis of structures under excitations, represented by multiple random processes that are correlated in both time and spatial domains. In KLE, the auto-covariance functions of random excitations are discretized using orthogonal basis functions. The KLE for multiple correlated random excitations relies on expansions in terms of correlated sets of random variables reflecting the cross-covariance of the random processes. During the response calculations, the eigenfunctions of KLE used to represent excitations are applied as forcing functions to the structure. The proposed algorithm is applied to a 2DOF system, a 2D cantilever beam and a 3D aircraft wing under both stationary and non-stationary correlated random excitations. Two methods are adopted to obtain the structural responses: a) the modal method and b) the direct method. Both the methods provide the statistics of the dynamic response with sufficient accuracy. The structural responses under the same type of correlated random excitations are bounded by the response obtained by perfectly correlated and uncorrelated random excitations. The structural response increases with a decrease in the correlation length and with an increase in the correlation magnitude. The proposed methodology can be applied for the analysis of any complex structure under any type of random excitation.

  5. Low-power adiabatic 9T static random access memory

    Directory of Open Access Journals (Sweden)

    Yasuhiro Takahashi

    2014-06-01

    Full Text Available In this paper, the authors propose a novel static random access memory (SRAM that employs the adiabatic logic principle. To reduce energy dissipation, the proposed adiabatic SRAM is driven by two trapezoidal-wave pulses. The cell structure of the proposed SRAM has two high-value resistors based on a p-type metal-oxide semiconductor transistor, a cross-coupled n-type metal-oxide semiconductor (NMOS pair and an NMOS switch to reduce the short-circuit current. The inclusion of a transmission-gate controlled by a write word line signal allows the proposed circuit to operate as an adiabatic SRAM during data writing. Simulation results show that the energy dissipation of the proposed SRAM is lower than that of a conventional adiabatic SRAM.

  6. Hydrogen doping in HfO2 resistance change random access memory

    Science.gov (United States)

    Duncan, D.; Magyari-Köpe, B.; Nishi, Y.

    2016-01-01

    The structures and energies of hydrogen-doped monoclinic hafnium dioxide were calculated using density-functional theory. The electronic interactions are described within the LDA + U formalism, where on-site Coulomb corrections are applied to the 5d orbital electrons of Hf atoms and 2p orbital electrons of the O atoms. The effects of charge state, defect-defect interactions, and hydrogenation are investigated and compared with experiment. It is found that hydrogenation of HfO2 resistance-change random access memory devices energetically stabilizes the formation of oxygen vacancies and conductive vacancy filaments through multiple mechanisms, leading to improved switching characteristic and device yield.

  7. SOME SYSTEMATIC SAMPLING STRATEGIES USING MULTIPLE RANDOM STARTS

    Directory of Open Access Journals (Sweden)

    Sampath Sundaram

    2010-09-01

    Full Text Available In this paper an attempt is made to extend linear systematic sampling using multiple random starts due to Gautschi(1957for various types of systematic sampling schemes available in literature, namely(i  Balanced Systematic Sampling (BSS of  Sethi (1965 and (ii Modified Systematic Sampling (MSS of Singh, Jindal, and Garg  (1968. Further, the proposed methods were compared with Yates corrected estimator developed with reference to Gautschi’s Linear systematic sampling (LSS with two random starts using appropriate super population models with the  help of R package for statistical computing.

  8. SOME SYSTEMATIC SAMPLING STRATEGIES USING MULTIPLE RANDOM STARTS

    OpenAIRE

    Sampath Sundaram; Ammani Sivaraman

    2010-01-01

    In this paper an attempt is made to extend linear systematic sampling using multiple random starts due to Gautschi(1957)for various types of systematic sampling schemes available in literature, namely(i)  Balanced Systematic Sampling (BSS) of  Sethi (1965) and (ii) Modified Systematic Sampling (MSS) of Singh, Jindal, and Garg  (1968). Further, the proposed methods were compared with Yates corrected estimator developed with reference to Gautschi’s Linear systematic samplin...

  9. Multiplicity of summands in the random partitions of an integer

    Indian Academy of Sciences (India)

    Theoretical Statistics and Mathematics Unit, Indian Statistical Institute, ... probability that there is a summand of multiplicity j in any randomly chosen partition or ... Introduction. 1.1 Integer partitions. Let n ≥ 1 be any integer and let n = a1 +a2 +···+am for some m ≥ 1 and some positive integers {ai }m i=1. We define the set {a1 ...

  10. Random Access Performance of Distributed Sensors Attacked by Unknown Jammers.

    Science.gov (United States)

    Jeong, Dae-Kyo; Wui, Jung-Hwa; Kim, Dongwoo

    2017-11-18

    In this paper, we model and investigate the random access (RA) performance of sensor nodes (SN) in a wireless sensor network (WSN). In the WSN, a central head sensor (HS) collects the information from distributed SNs, and jammers disturb the information transmission primarily by generating interference. In this paper, two jamming attacks are considered: power and code jamming. Power jammers (if they are friendly jammers) generate noises and, as a result, degrade the quality of the signal from SNs. Power jamming is equally harmful to all the SNs that are accessing HS and simply induces denial of service (DoS) without any need to hack HS or SNs. On the other hand, code jammers mimic legitimate SNs by sending fake signals and thus need to know certain system parameters that are used by the legitimate SNs. As a result of code jamming, HS falsely allocates radio resources to SNs. The code jamming hence increases the failure probability in sending the information messages, as well as misleads the usage of radio resources. In this paper, we present the probabilities of successful preamble transmission with power ramping according to the jammer types and provide the resulting throughput and delay of information transmission by SNs, respectively. The effect of two jamming attacks on the RA performances is compared with numerical investigation. The results show that, compared to RA without jammers, power and code jamming degrade the throughput by up to 30.3% and 40.5%, respectively, while the delay performance by up to 40.1% and 65.6%, respectively.

  11. Random Access Performance of Distributed Sensors Attacked by Unknown Jammers

    Directory of Open Access Journals (Sweden)

    Dae-Kyo Jeong

    2017-11-01

    Full Text Available In this paper, we model and investigate the random access (RA performance of sensor nodes (SN in a wireless sensor network (WSN. In the WSN, a central head sensor (HS collects the information from distributed SNs, and jammers disturb the information transmission primarily by generating interference. In this paper, two jamming attacks are considered: power and code jamming. Power jammers (if they are friendly jammers generate noises and, as a result, degrade the quality of the signal from SNs. Power jamming is equally harmful to all the SNs that are accessing HS and simply induces denial of service (DoS without any need to hack HS or SNs. On the other hand, code jammers mimic legitimate SNs by sending fake signals and thus need to know certain system parameters that are used by the legitimate SNs. As a result of code jamming, HS falsely allocates radio resources to SNs. The code jamming hence increases the failure probability in sending the information messages, as well as misleads the usage of radio resources. In this paper, we present the probabilities of successful preamble transmission with power ramping according to the jammer types and provide the resulting throughput and delay of information transmission by SNs, respectively. The effect of two jamming attacks on the RA performances is compared with numerical investigation. The results show that, compared to RA without jammers, power and code jamming degrade the throughput by up to 30.3% and 40.5%, respectively, while the delay performance by up to 40.1% and 65.6%, respectively.

  12. Distortion of the Stoner-Wohlfarth Astroid by Perpendicular Polarizer in Magnetic Random Access Memory

    Science.gov (United States)

    Chang, Jui-Hang; Chang, Ching-Ray

    2012-02-01

    For a spin-transfer-torque (STT) magnetic random access memory (MRAM) with a perpendicular polarizer under an external in-plane magnetic field, a distorted astroid of critical strength of STT and field is derived from an one-dimensional effective free energy. The modified astroid not only separates the multiple stable states from the monostable state, but also delimit the region of dynamical stable state as the STT achieving a critical magnitude. Taking into account of the STT, multiple-step magnetization switching of the STT-MRAM has been investigated. We gave a phase diagram for the single-step, double-step, and triple-step switchings, which are observed at a certain range of the external field angle and of the current density.

  13. Multiple Access Techniques for Next Generation Wireless: Recent Advances and Future Perspectives

    Directory of Open Access Journals (Sweden)

    Shree Krishna Sharma

    2016-01-01

    Full Text Available The advances in multiple access techniques has been one of the key drivers in moving from one cellular generation to another. Starting from the first generation, several multiple access techniques have been explored in different generations and various emerging multiplexing/multiple access techniques are being investigated for the next generation of cellular networks. In this context, this paper first provides a detailed review on the existing Space Division Multiple Access (SDMA related works. Subsequently, it highlights the main features and the drawbacks of various existing and emerging multiplexing/multiple access techniques. Finally, we propose a novel concept of clustered orthogonal signature division multiple access for the next generation of cellular networks. The proposed concept envisions to employ joint antenna coding in order to enhance the orthogonality of SDMA beams with the objective of enhancing the spectral efficiency of future cellular networks.

  14. Molecular Code Division Multiple Access: Gaussian Mixture Modeling

    Science.gov (United States)

    Zamiri-Jafarian, Yeganeh

    Communications between nano-devices is an emerging research field in nanotechnology. Molecular Communication (MC), which is a bio-inspired paradigm, is a promising technique for communication in nano-network. In MC, molecules are administered to exchange information among nano-devices. Due to the nature of molecular signals, traditional communication methods can't be directly applied to the MC framework. The objective of this thesis is to present novel diffusion-based MC methods when multi nano-devices communicate with each other in the same environment. A new channel model and detection technique, along with a molecular-based access method, are proposed in here for communication between asynchronous users. In this work, the received molecular signal is modeled as a Gaussian mixture distribution when the MC system undergoes Brownian noise and inter-symbol interference (ISI). This novel approach demonstrates a suitable modeling for diffusion-based MC system. Using the proposed Gaussian mixture model, a simple receiver is designed by minimizing the error probability. To determine an optimum detection threshold, an iterative algorithm is derived which minimizes a linear approximation of the error probability function. Also, a memory-based receiver is proposed to improve the performance of the MC system by considering previously detected symbols in obtaining the threshold value. Numerical evaluations reveal that theoretical analysis of the bit error rate (BER) performance based on the Gaussian mixture model match simulation results very closely. Furthermore, in this thesis, molecular code division multiple access (MCDMA) is proposed to overcome the inter-user interference (IUI) caused by asynchronous users communicating in a shared propagation environment. Based on the selected molecular codes, a chip detection scheme with an adaptable threshold value is developed for the MCDMA system when the proposed Gaussian mixture model is considered. Results indicate that the

  15. Overview of Sparse Graph for Multiple Access in Future Mobile Networks

    Science.gov (United States)

    Lei, Jing; Li, Baoguo; Li, Erbao; Gong, Zhenghui

    2017-10-01

    Multiple access via sparse graph, such as low density signature (LDS) and sparse code multiple access (SCMA), is a promising technique for future wireless communications. This survey presents an overview of the developments in this burgeoning field, including transmitter structures, extrinsic information transform (EXIT) chart analysis and comparisons with existing multiple access techniques. Such technique enables multiple access under overloaded conditions to achieve a satisfactory performance. Message passing algorithm is utilized for multi-user detection in the receiver, and structures of the sparse graph are illustrated in detail. Outlooks and challenges of this technique are also presented.

  16. Sequential multiple assignment randomization trials with enrichment design.

    Science.gov (United States)

    Liu, Ying; Wang, Yuanjia; Zeng, Donglin

    2017-06-01

    Sequential multiple assignment randomization trial (SMART) is a powerful design to study Dynamic Treatment Regimes (DTRs) and allows causal comparisons of DTRs. To handle practical challenges of SMART, we propose a SMART with Enrichment (SMARTER) design, which performs stage-wise enrichment for SMART. SMARTER can improve design efficiency, shorten the recruitment period, and partially reduce trial duration to make SMART more practical with limited time and resource. Specifically, at each subsequent stage of a SMART, we enrich the study sample with new patients who have received previous stages' treatments in a naturalistic fashion without randomization, and only randomize them among the current stage treatment options. One extreme case of the SMARTER is to synthesize separate independent single-stage randomized trials with patients who have received previous stage treatments. We show data from SMARTER allows for unbiased estimation of DTRs as SMART does under certain assumptions. Furthermore, we show analytically that the efficiency gain of the new design over SMART can be significant especially when the dropout rate is high. Lastly, extensive simulation studies are performed to demonstrate performance of SMARTER design, and sample size estimation in a scenario informed by real data from a SMART study is presented. © 2016, The International Biometric Society.

  17. 75 FR 55764 - Dynamic Random Access Memory Semiconductors From the Republic of Korea: Preliminary Results of...

    Science.gov (United States)

    2010-09-14

    ... memory, such as video graphics adapter boards and cards, are not included in the scope. The order also..., video random access memory and synchronous graphics random access memory, as well as various types of... for Foreign Technicians (Article 18 of RSTA) G. Reduction of Tax Regarding the Movement of a Factory...

  18. Performance analysis of commercial multiple-input-multiple-output access point in distributed antenna system.

    Science.gov (United States)

    Fan, Yuting; Aighobahi, Anthony E; Gomes, Nathan J; Xu, Kun; Li, Jianqiang

    2015-03-23

    In this paper, we experimentally investigate the throughput of IEEE 802.11n 2x2 multiple-input-multiple-output (MIMO) signals in a radio-over-fiber-based distributed antenna system (DAS) with different fiber lengths and power imbalance. Both a MIMO-supported access point (AP) and a spatial-diversity-supported AP were separately employed in the experiments. Throughput measurements were carried out with wireless users at different locations in a typical office environment. For the different fiber length effect, the results indicate that MIMO signals can maintain high throughput when the fiber length difference between the two remote antenna units (RAUs) is under 100 m and falls quickly when the length difference is greater. For the spatial diversity signals, high throughput can be maintained even when the difference is 150 m. On the other hand, the separation of the MIMO antennas allows additional freedom in placing the antennas in strategic locations for overall improved system performance, although it may also lead to received power imbalance problems. The results show that the throughput performance drops in specific positions when the received power imbalance is above around 13 dB. Hence, there is a trade-off between the extent of the wireless coverage for moderate bit-rates and the area over which peak bit-rates can be achieved.

  19. A Multi-channel Multiple Access Scheme Using Frequency Offsets - Modelling and Analysis

    NARCIS (Netherlands)

    Morshed, S.; Baratchi, Mitra; Mandal, Pranab K.; Heijenk, Geert

    2016-01-01

    A system using frequency offset based transmit- reference (TR) modulation allows multiple nodes to transmit simultaneously and asynchronously without any mutual timing coordination. Thus, such a system provides inherent capabilities for a multiple access in the medium access control (MAC) layer to

  20. Optimal design of queueing systems for using communication channels with multiple access

    Science.gov (United States)

    Sonkin, D. M.; Nazarov, A. A.; Khrul, S. A.; Kudryashova, A. V.

    2017-01-01

    This article considers the mathematical model of queueing systems for the communication network with multiple access, which is used in the automated group of moving objects control systems. The dynamic communication model in the form of a single-line queuing model with the batch input claims was researched. The method of asymptotic analysis of the communication channel under a heavy load conditions was applied. As a result, the basic probabilistic characteristics of the system were obtained, including: the probability distribution of the waiting time values of the virtual claims, the average length of the queue claims at random time. It has been discovered that the characteristics of the communications models allow performing parametric optimization of communication networks, establishing the most appropriate values of the network parameters.

  1. Proceedings of the Mobile Satellite System Architectures and Multiple Access Techniques Workshop

    Science.gov (United States)

    Dessouky, Khaled

    1989-01-01

    The Mobile Satellite System Architectures and Multiple Access Techniques Workshop served as a forum for the debate of system and network architecture issues. Particular emphasis was on those issues relating to the choice of multiple access technique(s) for the Mobile Satellite Service (MSS). These proceedings contain articles that expand upon the 12 presentations given in the workshop. Contrasting views on Frequency Division Multiple Access (FDMA), Code Division Multiple Access (CDMA), and Time Division Multiple Access (TDMA)-based architectures are presented, and system issues relating to signaling, spacecraft design, and network management constraints are addressed. An overview article that summarizes the issues raised in the numerous discussion periods of the workshop is also included.

  2. Controllable quantized conductance for multilevel data storage applications using conductive bridge random access memory

    Science.gov (United States)

    Gochole Aga, Fekadu; Woo, Jiyong; Song, Jeonghwan; Park, Jaehyuk; Lim, Seokjae; Sung, Changhyuck; Hwang, Hyunsang

    2017-03-01

    In this paper, we investigate the quantized conduction behavior of conductive bridge random access memory (CBRAM) with varied materials and ramping rates. We report stable and reproducible quantized conductance states with integer multiples of fundamental conductance obtained by optimizing the voltage ramping rate and the Ti-diffusion barrier (DB) at the Cu/HfO2 interface. Owing to controlled diffusion of Cu ions by the Ti-DB and the optimized ramping rate, through which it was possible to control the time delay of Cu ion reduction, more than seven levels of discrete conductance states were clearly observed. Analytical modeling was performed to determine the rate-limiting step in filament growth based on an electrochemical redox reaction. Our understanding of the fundamental mechanisms of quantized conductance behaviors provide a promising future for the multi-bit CBRAM device.

  3. Understanding Electrical Conduction States in WO3 Thin Films Applied for Resistive Random-Access Memory

    Science.gov (United States)

    Ta, Thi Kieu Hanh; Pham, Kim Ngoc; Dao, Thi Bang Tam; Tran, Dai Lam; Phan, Bach Thang

    2016-05-01

    The electrical conduction and associated resistance switching mechanism of top electrode/WO3/bottom electrode devices [top electrode (TE): Ag, Ti; bottom electrode (BE): Pt, fluorine-doped tin oxide] have been investigated. The direction of switching and switching ability depended on both the top and bottom electrode material. Multiple electrical conduction mechanisms control the leakage current of such switching devices, including trap-controlled space-charge, ballistic, Ohmic, and Fowler-Nordheim tunneling effects. The transition between electrical conduction states is also linked to the switching (SET-RESET) process. This is the first report of ballistic conduction in research into resistive random-access memory. The associated resistive switching mechanisms are also discussed.

  4. Massive Access Control Aided by Knowledge-Extraction for Co-Existing Periodic and Random Services over Wireless Clinical Networks.

    Science.gov (United States)

    Du, Qinghe; Zhao, Weidong; Li, Weimin; Zhang, Xuelin; Sun, Bo; Song, Houbing; Ren, Pinyi; Sun, Li; Wang, Yichen

    2016-07-01

    The prosperity of e-health is boosted by fast development of medical devices with wireless communications capability such as wearable devices, tiny sensors, monitoring equipments, etc., which are randomly distributed in clinic environments. The drastically-increasing population of such devices imposes new challenges on the limited wireless resources. To relieve this problem, key knowledge needs to be extracted from massive connection attempts dispersed in the air towards efficient access control. In this paper, a hybrid periodic-random massive access (HPRMA) scheme for wireless clinical networks employing ultra-narrow band (UNB) techniques is proposed. In particular, the proposed scheme towards accommodating a large population of devices include the following new features. On one hand, it can dynamically adjust the resource allocated for coexisting periodic and random services based on the traffic load learned from signal collision status. On the other hand, the resource allocation within periodic services is thoroughly designed to simultaneously align with the timing requests of differentiated services. Abundant simulation results are also presented to demonstrate the superiority of the proposed HPRMA scheme over baseline schemes including time-division multiple access (TDMA) and random access approach, in terms of channel utilization efficiency, packet drop ratio, etc., for the support of massive devices' services.

  5. A randomized pilot study of naturopathic medicine in multiple sclerosis.

    Science.gov (United States)

    Shinto, Lynne; Calabrese, Carlo; Morris, Cynthia; Yadav, Vijayshree; Griffith, Debbie; Frank, Rachel; Oken, Barry S; Baldauf-Wagner, Sara; Bourdette, Dennis

    2008-06-01

    Complementary and alternative medicine (CAM) use is high in people with multiple sclerosis (MS), yet there are limited reports on safety and effectiveness of CAM in MS. Naturopathic medicine encompasses a broad range of CAM modalities and may improve quality of life in patients with MS. To assess quality of life in MS subjects who received interventions designed to "model" the "whole practice" of naturopathy. A pilot, randomized, controlled study with a 6-month intervention period. Participants who met criteria for clinically definite MS. The 3 intervention arms were usual care, naturopathic medicine plus usual care, and MS education plus usual care. The primary outcome measure was quality of life (36-item short form health survey [SF-36]). Secondary outcome measures included fatigue (Modified Fatigue Impact Scale); depression (Beck Depression Inventory); cognition battery (Stroop test and Paced Auditory Serial Addition Test 3), and neurologic impairment (Expanded Disability Status Scale [EDSS] and Multiple Sclerosis Functional Composite). Adverse event reporting and laboratory measures were used to assess safety. Forty-five (45) participants (15 per group) were randomized and all completed the 6-month intervention. There were no significant differences between groups on any outcome measure. There was a trend in favoring the naturopathic group in the General Health subscale of the SF-36 (p = 0.11), Timed Walk (p = 0.11), and neurologic impairment (EDSS) (p = 0.07). There was a trend favoring the Education group in the Stroop attention test (p = 0.07). There was no difference between groups in adverse events or laboratory changes. Naturopathic medicine combined with usual care for MS showed a trend in improvement in the General Health subscale of the SF-36, Timed Walk, and neurologic impairment. Evaluation of naturopathic medicine, as a multimodality regimen, warrants further investigation.

  6. Adaptive Information Access on Multiple Applications Support Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Tobgay, Sonam; Olsen, Rasmus Løvenstein; Prasad, Ramjee

    2014-01-01

    is used for safety and security monitoring purposes. In this paper, we evaluate different access strategies to remote dynamic information and compare between achieving information reliability (mismatch probability) and the associated power consumption. Lastly, based on the models, we propose an adaptive......Accessing information remotely to dynamically changing information elements cannot be avoided and has become a required functionality for various network services. Most applications require up-to-date information which is reliable and accurate. The information reliability in terms of using correct...... information is challenged by dynamic nature of information elements. These challenges are more prominent in case of wireless sensor network (WSN) applications, as the information that the sensor node collects are mostly dynamic in nature (say, temperature). Therefore, it is likely that there can be a mismatch...

  7. Mendelian randomization analysis with multiple genetic variants using summarized data.

    Science.gov (United States)

    Burgess, Stephen; Butterworth, Adam; Thompson, Simon G

    2013-11-01

    Genome-wide association studies, which typically report regression coefficients summarizing the associations of many genetic variants with various traits, are potentially a powerful source of data for Mendelian randomization investigations. We demonstrate how such coefficients from multiple variants can be combined in a Mendelian randomization analysis to estimate the causal effect of a risk factor on an outcome. The bias and efficiency of estimates based on summarized data are compared to those based on individual-level data in simulation studies. We investigate the impact of gene-gene interactions, linkage disequilibrium, and 'weak instruments' on these estimates. Both an inverse-variance weighted average of variant-specific associations and a likelihood-based approach for summarized data give similar estimates and precision to the two-stage least squares method for individual-level data, even when there are gene-gene interactions. However, these summarized data methods overstate precision when variants are in linkage disequilibrium. If the P-value in a linear regression of the risk factor for each variant is less than 1×10⁻⁵, then weak instrument bias will be small. We use these methods to estimate the causal association of low-density lipoprotein cholesterol (LDL-C) on coronary artery disease using published data on five genetic variants. A 30% reduction in LDL-C is estimated to reduce coronary artery disease risk by 67% (95% CI: 54% to 76%). We conclude that Mendelian randomization investigations using summarized data from uncorrelated variants are similarly efficient to those using individual-level data, although the necessary assumptions cannot be so fully assessed. © 2013 WILEY PERIODICALS, INC.

  8. Binary Sequences for Spread-Spectrum Multiple-Access Communication

    Science.gov (United States)

    1977-08-01

    extensively in the literature by Zierler (1959) and Golomb (1967) and others. 3.1. Introduction to m-sequences It is convenient to distinguish in our...overview of the problems and programs," Proceedings of the IEEE, vol. 65, pp. 294-307, 1977. Puente , J. 0., Schmidt, W. G., and Werth, A. M., "Multiple

  9. Parity-Check Network Coding for Multiple Access Relay Channel in Wireless Sensor Cooperative Communications

    Directory of Open Access Journals (Sweden)

    Du Bing

    2010-01-01

    Full Text Available A recently developed theory suggests that network coding is a generalization of source coding and channel coding and thus yields a significant performance improvement in terms of throughput and spatial diversity. This paper proposes a cooperative design of a parity-check network coding scheme in the context of a two-source multiple access relay channel (MARC model, a common compact model in hierarchical wireless sensor networks (WSNs. The scheme uses Low-Density Parity-Check (LDPC as the surrogate to build up a layered structure which encapsulates the multiple constituent LDPC codes in the source and relay nodes. Specifically, the relay node decodes the messages from two sources, which are used to generate extra parity-check bits by a random network coding procedure to fill up the rate gap between Source-Relay and Source-Destination transmissions. Then, we derived the key algebraic relationships among multidimensional LDPC constituent codes as one of the constraints for code profile optimization. These extra check bits are sent to the destination to realize a cooperative diversity as well as to approach MARC decode-and-forward (DF capacity.

  10. Evaluation of Data Retention Characteristics for Ferroelectric Random Access Memories (FRAMs)

    Science.gov (United States)

    Sharma, Ashok K.; Teverovsky, Alexander

    2001-01-01

    Data retention and fatigue characteristics of 64 Kb lead zirconate titanate (PZT)-based Ferroelectric Random Access Memories (FRAMs) microcircuits manufactured by Ramtron were examined over temperature range from -85 C to +310 C for ceramic packaged parts and from -85 C to +175 C for plastic parts, during retention periods up to several thousand hours. Intrinsic failures, which were caused by a thermal degradation of the ferroelectric cells, occurred in ceramic parts after tens or hundreds hours of aging at temperatures above 200 C. The activation energy of the retention test failures was 1.05 eV and the extrapolated mean-time-to-failure (MTTF) at room temperature was estimated to be more than 280 years. Multiple write-read cycling (up to 3x10(exp 7)) during the fatigue testing of plastic and ceramic parts did not result in any parametric or functional failures. However, operational currents linearly decreased with the logarithm of number of cycles thus indicating fatigue process in PZT films. Plastic parts, that had more recent date code as compared to ceramic parts, appeared to be using die with improved process technology and showed significantly smaller changes in operational currents and data access times.

  11. Performance Analysis of Multi-Service Oriented Multiple Access Under General Channel Correlation

    OpenAIRE

    Ksairi, Nassar; Debbah, Mérouane

    2017-01-01

    In this article, we provide both analytical and numerical performance analysis of multi-service oriented multiple access (MOMA), a recently proposed non-orthogonal multiple-access scheme for scenarios with a massive number of concurrent connections originating from separate service classes with diverse quality-of-service (QoS) profiles and running on both handheld terminals and Internet-of-Things (IoT) devices. MOMA is based on both class dependent hierarchical-spreading transmission scheme a...

  12. Experimental demonstration of block interleaved frequency division multiple access for bidirectional visible light communications

    Science.gov (United States)

    Lin, Bangjiang; Yang, Hui; Ye, Weiping; Tang, Xuan; Ghassemlooy, Zabih

    2017-01-01

    We propose a power efficient multiple access scheme for visible light communications (VLC) based on the block interleaved frequency division multiple access (B-IFDMA) which provides large frequency-diversity, flexible bandwidth allocation, low complexity of channel equalization, and user separation. Bidirectional B-IFDMA VLC transmission is experimentally demonstrated to verify its feasibility. The impact of the number of subcarriers per block on the transmission performance under wireless optical channel is investigated.

  13. Randomized trial of oral teriflunomide for relapsing multiple sclerosis.

    Science.gov (United States)

    O'Connor, Paul; Wolinsky, Jerry S; Confavreux, Christian; Comi, Giancarlo; Kappos, Ludwig; Olsson, Tomas P; Benzerdjeb, Hadj; Truffinet, Philippe; Wang, Lin; Miller, Aaron; Freedman, Mark S

    2011-10-06

    Teriflunomide is a new oral disease-modifying therapy for relapsing forms of multiple sclerosis. We concluded a randomized trial involving 1088 patients with multiple sclerosis, 18 to 55 years of age, with a score of 0 to 5.5 on the Expanded Disability Status Scale and at least one relapse in the previous year or at least two relapses in the previous 2 years. Patients were randomly assigned (in a 1:1:1 ratio) to placebo, 7 mg of teriflunomide, or 14 mg of teriflunomide once daily for 108 weeks. The primary end point was the annualized relapse rate, and the key secondary end point was confirmed progression of disability for at least 12 weeks. Teriflunomide reduced the annualized relapse rate (0.54 for placebo vs. 0.37 for teriflunomide at either 7 or 14 mg), with relative risk reductions of 31.2% and 31.5%, respectively (Pteriflunomide at 7 mg (P=0.08), and 20.2% with teriflunomide at 14 mg (P=0.03). Both teriflunomide doses were superior to placebo on a range of end points measured by magnetic resonance imaging (MRI). Diarrhea, nausea, and hair thinning were more common with teriflunomide than with placebo. The incidence of elevated alanine aminotransferase levels (≥1 times the upper limit of the normal range) was higher with teriflunomide at 7 mg and 14 mg (54.0% and 57.3%, respectively) than with placebo (35.9%); the incidence of levels that were at least 3 times the upper limit of the normal range was similar in the lower- and higher-dose teriflunomide groups and the placebo group (6.3%, 6.7%, and 6.7%, respectively). Serious infections were reported in 1.6%, 2.5%, and 2.2% of patients in the three groups, respectively. No deaths occurred. Teriflunomide significantly reduced relapse rates, disability progression (at the higher dose), and MRI evidence of disease activity, as compared with placebo. (Funded by Sanofi-Aventis; TEMSO ClinicalTrials.gov number, NCT00134563.).

  14. Optimizing Orthogonal Multiple Access based on Quantized Channel State Information

    CERN Document Server

    Marques, Antonio G; Ramos, Javier

    2009-01-01

    The performance of systems where multiple users communicate over wireless fading links benefits from channel-adaptive allocation of the available resources. Different from most existing approaches that allocate resources based on perfect channel state information, this work optimizes channel scheduling along with per user rate and power loadings over orthogonal fading channels, when both terminals and scheduler rely on quantized channel state information. Channel-adaptive policies are designed to optimize an average transmit-performance criterion subject to average quality of service requirements. While the resultant optimal policy per fading realization shows that the individual rate and power loadings can be obtained separately for each user, the optimal scheduling is slightly more complicated. Specifically, per fading realization each channel is allocated either to a single (winner) user, or, to a small group of winner users whose percentage of shared resources is found by solving a linear program. A singl...

  15. Aspects of GPU perfomance in algorithms with random memory access

    Science.gov (United States)

    Kashkovsky, Alexander V.; Shershnev, Anton A.; Vashchenkov, Pavel V.

    2017-10-01

    The numerical code for solving the Boltzmann equation on the hybrid computational cluster using the Direct Simulation Monte Carlo (DSMC) method showed that on Tesla K40 accelerators computational performance drops dramatically with increase of percentage of occupied GPU memory. Testing revealed that memory access time increases tens of times after certain critical percentage of memory is occupied. Moreover, it seems to be the common problem of all NVidia's GPUs arising from its architecture. Few modifications of the numerical algorithm were suggested to overcome this problem. One of them, based on the splitting the memory into "virtual" blocks, resulted in 2.5 times speed up.

  16. Mof-Tree: A Spatial Access Method To Manipulate Multiple Overlapping Features.

    Science.gov (United States)

    Manolopoulos, Yannis; Nardelli, Enrico; Papadopoulos, Apostolos; Proietti, Guido

    1997-01-01

    Investigates the manipulation of large sets of two-dimensional data representing multiple overlapping features, and presents a new access method, the MOF-tree. Analyzes storage requirements and time with respect to window query operations involving multiple features. Examines both the pointer-based and pointerless MOF-tree representations.…

  17. Teaching Individuals with Profound Multiple Disabilities to Access Preferred Stimuli with Multiple Microswitches

    Science.gov (United States)

    Tam, Gee May; Phillips, Katrina J.; Mudford, Oliver C.

    2011-01-01

    We replicated and extended previous research on microswitch facilitated choice making by individuals with profound multiple disabilities. Following an assessment of stimulus preferences, we taught 6 adults with profound multiple disabilities to emit 2 different responses to activate highly preferred stimuli. All participants learnt to activate…

  18. Radial Access Reduces Mortality in Patients With Acute Coronary Syndromes: Results From an Updated Trial Sequential Analysis of Randomized Trials.

    Science.gov (United States)

    Andò, Giuseppe; Capodanno, Davide

    2016-04-11

    The authors sought to investigate whether the cumulative evidence coming from randomized studies has reached the necessary power to consider radial access as a bleeding avoidance strategy that reduces mortality and ischemic endpoints in patients with acute coronary syndromes (ACS). Studies in ACS patients have reached conflicting conclusions about the impact of radial access in improving ischemic outcomes in addition to the established bleeding benefit. English-language publications and abstracts of major cardiovascular meetings until October 2015 were scrutinized. Study quality, patient characteristics, procedural data, and outcomes were extracted. Data were pooled in random effects meta-analyses with classic and trial sequential techniques. Trial sequential analysis combines the a priori information size calculation needed to allow for clinically meaningful statistical inference with the adjustment of thresholds for which results are considered significant. Seventeen studies, encompassing data from 19,328 patients, were pooled. Radial access was found to reduce mortality (relative risk [RR]: 0.73; 95% confidence interval [CI]: 0.60 to 0.88; p = 0.001), major adverse cardiovascular events (RR: 0.86; 95% CI: 0.77 to 0.95; p = 0.005), and major bleeding (RR: 0.60; 95% CI: 0.48 to 0.76; p < 0.001). Multiple sensitivity analyses showed consistent results, and trial sequential analysis suggested firm evidence for a meaningful reduction in mortality with radial access. Radial access reduces mortality compared with femoral access in ACS patients undergoing invasive management. This benefit is paralleled by consistent reductions in major adverse cardiovascular events and major bleeding, supporting radial access as the default strategy for cardiac catheterization in patients with ACS. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  19. Randomized trial of oral teriflunomide for relapsing multiple sclerosis

    DEFF Research Database (Denmark)

    O'Connor, Paul; Wolinsky, Jerry S; Confavreux, Christian

    2011-01-01

    Teriflunomide is a new oral disease-modifying therapy for relapsing forms of multiple sclerosis.......Teriflunomide is a new oral disease-modifying therapy for relapsing forms of multiple sclerosis....

  20. Design of pulse waveform for waveform division multiple access UWB wireless communication system.

    Science.gov (United States)

    Yin, Zhendong; Wang, Zhirui; Liu, Xiaohui; Wu, Zhilu

    2014-01-01

    A new multiple access scheme, Waveform Division Multiple Access (WDMA) based on the orthogonal wavelet function, is presented. After studying the correlation properties of different categories of single wavelet functions, the one with the best correlation property will be chosen as the foundation for combined waveform. In the communication system, each user is assigned to different combined orthogonal waveform. Demonstrated by simulation, combined waveform is more suitable than single wavelet function to be a communication medium in WDMA system. Due to the excellent orthogonality, the bit error rate (BER) of multiuser with combined waveforms is so close to that of single user in a synchronous system. That is to say, the multiple access interference (MAI) is almost eliminated. Furthermore, even in an asynchronous system without multiuser detection after matched filters, the result is still pretty ideal and satisfactory by using the third combination mode that will be mentioned in the study.

  1. A random effect multiplicative heteroscedastic model for bacterial growth

    Directory of Open Access Journals (Sweden)

    Quinto Emiliano J

    2010-02-01

    Full Text Available Abstract Background Predictive microbiology develops mathematical models that can predict the growth rate of a microorganism population under a set of environmental conditions. Many primary growth models have been proposed. However, when primary models are applied to bacterial growth curves, the biological variability is reduced to a single curve defined by some kinetic parameters (lag time and growth rate, and sometimes the models give poor fits in some regions of the curve. The development of a prediction band (from a set of bacterial growth curves using non-parametric and bootstrap methods permits to overcome that problem and include the biological variability of the microorganism into the modelling process. Results Absorbance data from Listeria monocytogenes cultured at 22, 26, 38, and 42°C were selected under different environmental conditions of pH (4.5, 5.5, 6.5, and 7.4 and percentage of NaCl (2.5, 3.5, 4.5, and 5.5. Transformation of absorbance data to viable count data was carried out. A random effect multiplicative heteroscedastic model was considered to explain the dynamics of bacterial growth. The concept of a prediction band for microbial growth is proposed. The bootstrap method was used to obtain resamples from this model. An iterative procedure is proposed to overcome the computer intensive task of calculating simultaneous prediction intervals, along time, for bacterial growth. The bands were narrower below the inflection point (0-8 h at 22°C, and 0-5.5 h at 42°C, and wider to the right of it (from 9 h onwards at 22°C, and from 7 h onwards at 42°C. A wider band was observed at 42°C than at 22°C when the curves reach their upper asymptote. Similar bands have been obtained for 26 and 38°C. Conclusions The combination of nonparametric models and bootstrap techniques results in a good procedure to obtain reliable prediction bands in this context. Moreover, the new iterative algorithm proposed in this paper allows one to

  2. Non-Orthogonal Random Access in MIMO Cognitive Radio Networks: Beamforming, Power Allocation, and Opportunistic Transmission.

    Directory of Open Access Journals (Sweden)

    Huifa Lin

    Full Text Available We study secondary random access in multi-input multi-output cognitive radio networks, where a slotted ALOHA-type protocol and successive interference cancellation are used. We first introduce three types of transmit beamforming performed by secondary users, where multiple antennas are used to suppress the interference at the primary base station and/or to increase the received signal power at the secondary base station. Then, we show a simple decentralized power allocation along with the equivalent single-antenna conversion. To exploit the multiuser diversity gain, an opportunistic transmission protocol is proposed, where the secondary users generating less interference are opportunistically selected, resulting in a further reduction of the interference temperature. The proposed methods are validated via computer simulations. Numerical results show that increasing the number of transmit antennas can greatly reduce the interference temperature, while increasing the number of receive antennas leads to a reduction of the total transmit power. Optimal parameter values of the opportunistic transmission protocol are examined according to three types of beamforming and different antenna configurations, in terms of maximizing the cognitive transmission capacity. All the beamforming, decentralized power allocation, and opportunistic transmission protocol are performed by the secondary users in a decentralized manner, thus resulting in an easy implementation in practice.

  3. Non-Orthogonal Random Access in MIMO Cognitive Radio Networks: Beamforming, Power Allocation, and Opportunistic Transmission.

    Science.gov (United States)

    Lin, Huifa; Shin, Won-Yong

    2017-01-01

    We study secondary random access in multi-input multi-output cognitive radio networks, where a slotted ALOHA-type protocol and successive interference cancellation are used. We first introduce three types of transmit beamforming performed by secondary users, where multiple antennas are used to suppress the interference at the primary base station and/or to increase the received signal power at the secondary base station. Then, we show a simple decentralized power allocation along with the equivalent single-antenna conversion. To exploit the multiuser diversity gain, an opportunistic transmission protocol is proposed, where the secondary users generating less interference are opportunistically selected, resulting in a further reduction of the interference temperature. The proposed methods are validated via computer simulations. Numerical results show that increasing the number of transmit antennas can greatly reduce the interference temperature, while increasing the number of receive antennas leads to a reduction of the total transmit power. Optimal parameter values of the opportunistic transmission protocol are examined according to three types of beamforming and different antenna configurations, in terms of maximizing the cognitive transmission capacity. All the beamforming, decentralized power allocation, and opportunistic transmission protocol are performed by the secondary users in a decentralized manner, thus resulting in an easy implementation in practice.

  4. Average Likelihood Methods of Classification of Code Division Multiple Access (CDMA)

    Science.gov (United States)

    2016-05-01

    AVERAGE LIKELIHOOD METHODS OF CLASSIFICATION OF CODE DIVISION MULTIPLE ACCESS ( CDMA ) MAY 2016 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC RELEASE...ACCESS ( CDMA ) 5a. CONTRACT NUMBER IN-HOUSE / R193 5b. GRANT NUMBER N/A 5c. PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Alfredo Vega Irizarry 5d...ABSTRACT This final report summarizes the most significant findings under the in-house effort titled “Average Likelihood For CDMA ”. The effort included

  5. LTE-advanced random access mechanism for M2M communication: A review

    Science.gov (United States)

    Mustafa, Rashid; Sarowa, Sandeep; Jaglan, Reena Rathee; Khan, Mohammad Junaid; Agrawal, Sunil

    2016-03-01

    Machine Type Communications (MTC) enables one or more self-sufficient machines to communicate directly with one another without human interference. MTC applications include smart grid, security, e-Health and intelligent automation system. To support huge numbers of MTC devices, one of the challenging issues is to provide a competent way for numerous access in the network and to minimize network overload. In this article, the different control mechanisms for overload random access are reviewed to avoid congestion caused by random access channel (RACH) of MTC devices. However, past and present wireless technologies have been engineered for Human-to-Human (H2H) communications, in particular, for transmission of voice. Consequently the Long Term Evolution (LTE) -Advanced is expected to play a central role in communicating Machine to Machine (M2M) and are very optimistic about H2H communications. Distinct and unique characteristics of M2M communications create new challenges from those in H2H communications. In this article, we investigate the impact of massive M2M terminals attempting random access to LTE-Advanced all at once. We discuss and review the solutions to alleviate the overload problem by Third Generation Partnership Project (3GPP). As a result, we evaluate and compare these solutions that can effectively eliminate the congestion on the random access channel for M2M communications without affecting H2H communications.

  6. Low-sampling-rate M-ary multiple access UWB communications in multipath channels

    KAUST Repository

    Alkhodary, Mohammad T.

    2015-08-31

    The desirable characteristics of ultra-wideband (UWB) technology are challenged by formidable sampling frequency, performance degradation in the presence of multi-user interference, and complexity of the receiver due to the channel estimation process. In this paper, a low-rate-sampling technique is used to implement M-ary multiple access UWB communications, in both the detection and channel estimation stages. A novel approach is used for multiple-access-interference (MAI) cancelation for the purpose of channel estimation. Results show reasonable performance of the proposed receiver for different number of users operating many times below Nyquist rate.

  7. Multiple access protocol for supporting multimedia services in wireless ATM networks

    DEFF Research Database (Denmark)

    Liu, Hong; Dittmann, Lars; Gliese, Ulrik Bo

    1999-01-01

    The furture broadband wireless asynchronous transfer mode (ATM) networks must provide seamless extension of multimedia services from the wireline ATM networks. This requires an effecient wireless access protocol to fulfill varying Quality-og-Service (QoS) requirements for multimedia applications....... In this paper, we propose a multiple access protocol using centralized and distributed channel access control techniques to provide QoS guarantees for multimedia services by taking advantage of the characteristics of different kinds of ATM traffics. Multimedia traffic, including constant bit rate (CBR...

  8. Random access procedures and radio access network (RAN) overload control in standard and advanced long-term evolution (LTE and LTE-A) networks

    DEFF Research Database (Denmark)

    Kiilerich Pratas, Nuno; Thomsen, Henning; Popovski, Petar

    2015-01-01

    In this chapter, we describe and discuss the current LTE random access procedure and the Radio Access Network Load Control solution within LTE/LTE-A. We provide an overview of the several considered load control solutions and give a detailed description of the standardized Extended Access Class B...

  9. Random Access for Machine-Type Communication based on Bloom Filtering

    DEFF Research Database (Denmark)

    Pratas, Nuno; Stefanovic, Cedomir; Madueño, Germán Corrales

    2016-01-01

    We present a random access method inspired on Bloom filters that is suited for Machine-Type Communications (MTC). Each accessing device sends a signature during the contention process. A signature is constructed using the Bloom filtering method and contains information on the device identity...... utilizes the system resources more efficiently and achieves similar or lower latency of connection establishment in case of synchronous arrivals, compared to the variant of the LTE-A access protocol that is optimized for MTC traffic. A dividend of the proposed method is that allows the base station (BS...

  10. MULTIPLE ACCESS POINTS WITHIN THE ONLINE CLASSROOM: WHERE STUDENTS LOOK FOR INFORMATION

    Directory of Open Access Journals (Sweden)

    John STEELE

    2017-01-01

    Full Text Available The purpose of this study is to examine the impact of information placement within the confines of the online classroom architecture. Also reviewed was the impact of other variables such as course design, teaching presence and student patterns in looking for information. The sample population included students from a major online university in their first year course sequence. Students were tasked with completing a survey at the end of the course, indicating their preference for accessing information within the online classroom. The qualitative data indicated that student preference is to receive information from multiple access points and sources within the online classroom architecture. Students also expressed a desire to have information delivered through the usage of technology such as email and text messaging. In addition to receiving information from multiple sources, the qualitative data indicated students were satisfied overall, with the current ways in which they received and accessed information within the online classroom setting. Major findings suggest that instructors teaching within the online classroom should have multiple data access points within the classroom architecture. Furthermore, instructors should use a variety of communication venues to enhance the ability for students to access and receive information pertinent to the course.

  11. Nanostructure-property relations for phase-change random access memory (PCRAM) line cells

    NARCIS (Netherlands)

    Kooi, B. J.; Oosthoek, J. L. M.; Verheijen, M. A.; Kaiser, M.; Jedema, F. J.; Gravesteijn, D. J.

    2012-01-01

    Phase-change random access memory (PCRAM) cells have been studied extensively using electrical characterization and rather limited by detailed structure characterization. The combination of these two characterization techniques has hardly been exploited and it is the focus of the present work.

  12. Page 1 r Stability of multiple access communication networks 379 de ...

    Indian Academy of Sciences (India)

    Mosely J. Humblet P A 1985 A class of efficient contention resolution algorithms for multiple access. IEEE Trans. Connur. COM-33: 45-5. Nelson R 1984 The stochastic cusp, swallowtail and hyperbolic umbilic catastrophes as manifest in a simple communications model. Performance'84 (Amsterdam: Elsevier Science ...

  13. Request-TDMA: A multiple-access protocol for wireless multimedia networks

    NARCIS (Netherlands)

    Linnenbank, G.R.J.; Havinga, Paul J.M.; Smit, Gerardus Johannes Maria; Mullender, Sape J.; Smulders, P.; van den Meerendonk, H.

    1995-01-01

    This paper describes a cellular multiple-access scheme based on TDMA for multimedia communication networks. The scheme proposes an admission control of two different multimedia application stream types: real-time and non-real-time. We do not consider interference between cells. The proposed

  14. Knowledge-Based Multiple Access Protocol in Broadband Wireless ATM Networks

    DEFF Research Database (Denmark)

    Liu, Hong; Gliese, Ulrik Bo; Dittmann, Lars

    1999-01-01

    In this paper, we propose a knowledge-based multiple access protocol for the extension of wireline ATM to wireless networks. The objective is to enable effecient transmission of all kinds of ATM traffic in the wireless channel with guaranteed QoS.The proposed protocol utilixes knowledge of the main...... guaranteed QoS requirements to a variety of ATM applications....

  15. Optimization of multiple access equipment costs in earth stations for data satellite services

    Science.gov (United States)

    Kuch, T.; Garcia, R.; Weidenfeller, H.

    Cost tradeoffs for multiple-access systems in regional and international satellite networks and the associated modulation and coding equipment are analyzed. The analytic method is described, and its applications are briefly discussed. Results are presented for different combinations of modulation and FEC-coding types for TDMA or SCPC systems in various satellite environments and traffic patterns.

  16. On the concentration of the capacity for a code division multiple access system

    OpenAIRE

    Korada, Satish Babu; Macris, Nicolas

    2007-01-01

    We prove the concentration of the capacity, in the large system limit, for a code division multiple access system over an additive white Gaussian noise channel, with Gaussian signature sequences and {\\it binary input} symbols. The probabilistic tools that are used are quite powerful and could have applications in many other similar situations.

  17. Variable-length coding for short packets over a multiple access channel with feedback

    DEFF Research Database (Denmark)

    Trillingsgaard, Kasper Fløe; Popovski, Petar

    2014-01-01

    We consider a two-user discrete memoryless multiple access channel with a common stop-feedback signal from the receiver to both transmitters. The achievable regions are characterized using joint decoding and successive cancellation decoding and, it is shown that the achievable regions are signifi...

  18. A Combined Polling and Random Access Technique for Enhanced Anti-Collision Performance in RFID Systems

    Science.gov (United States)

    Kim, Jeong Geun

    In this paper we propose a novel RFID anti-collision technique that intelligently combines polling and random access schemes. These two fundamentally different medium access control protocols are coherently integrated in our design while functionally complementing each other. The polling mode is designed to enable fast collision-free identification for the tags that exist within reader's coverage across the sessions. In contrast, the random access mode attempts to read the tags uncovered by the polling mode. Our proposed technique is particularly suited for a class of RFID applications in which a stationary reader periodically attempts to identify the tags with slow mobility. Numerical results show that our proposed technique yields much faster identification time against the existing approaches under various operating conditions.

  19. Random Scenario Generation for a Multiple Target Tracking Environment Evaluation

    DEFF Research Database (Denmark)

    Hussain, Dil Muhammad Akbar

    2006-01-01

    The paper presents a simulation study on the generation of a random scenario for the performance of track splitting algorithm on a digital signal processor.  Much of the previous work [1] was done on specific (deterministic) scenarios. One of the reasons for considering the specific scenarios, wh...

  20. Lexical access changes in patients with multiple sclerosis: a two-year follow-up study.

    Science.gov (United States)

    Sepulcre, Jorge; Peraita, Herminia; Goni, Joaquin; Arrondo, Gonzalo; Martincorena, Inigo; Duque, Beatriz; Velez de Mendizabal, Nieves; Masdeu, Joseph C; Villoslada, Pablo

    2011-02-01

    The aim of the study was to analyze lexical access strategies in patients with multiple sclerosis (MS) and their changes over time. We studied lexical access strategies during semantic and phonemic verbal fluency tests and also confrontation naming in a 2-year prospective cohort of 45 MS patients and 20 healthy controls. At baseline, switching lexical access strategy (both in semantic and in phonemic verbal fluency tests) and confrontation naming were significantly impaired in MS patients compared with controls. After 2 years follow-up, switching score decreased, and cluster size increased over time in semantic verbal fluency tasks, suggesting a failure in the retrieval of lexical information rather than an impairment of the lexical pool. In conclusion, these findings underline the significant presence of lexical access problems in patients with MS and could point out their key role in the alterations of high-level communications abilities in MS.

  1. Measuring spatial accessibility to healthcare for populations with multiple transportation modes.

    Science.gov (United States)

    Mao, Liang; Nekorchuk, Dawn

    2013-11-01

    Few measures of healthcare accessibility have considered multiple transportation modes when people seek healthcare. Based on the framework of the 2 Step Floating Catchment Area Method (2SFCAM), we proposed an innovative method to incorporate transportation modes into the accessibility estimation. Taking Florida, USA, as a study area, we illustrated the implementation of the multi-mode 2SFCAM, and compared the accessibility estimates with those from the traditional single-mode 2SFCAM. The results suggest that the multi-modal method, by accounting for heterogeneity in populations, provides more realistic accessibility estimations, and thus offers a better guidance for policy makers to mitigate health inequity issues. © 2013 Elsevier Ltd. All rights reserved.

  2. Cognitive function in multiple sclerosis improves with telerehabilitation: Results from a randomized controlled trial.

    Directory of Open Access Journals (Sweden)

    Leigh E Charvet

    Full Text Available Cognitive impairment affects more than half of all individuals living with multiple sclerosis (MS. We hypothesized that training at home with an adaptive online cognitive training program would have greater cognitive benefit than ordinary computer games in cognitively-impaired adults with MS. This was a double-blind, randomized, active-placebo-controlled trial. Participants with MS were recruited through Stony Brook Medicine and randomly assigned to either the adaptive cognitive remediation (ACR program or active control of ordinary computer games for 60 hours over 12 weeks. Training was remotely-supervised and delivered through a study-provided laptop computer. A computer generated, blocked stratification table prepared by statistician provided the randomization schedule and condition was assigned by a study technician. The primary outcome, administered by study psychometrician, was measured by change in a neuropsychological composite measure from baseline to study end. An intent-to-treat analysis was employed and missing primary outcome values were imputed via Markov Chain Monte Carlo method. Participants in the ACR (n = 74 vs. active control (n = 61 training program had significantly greater improvement in the primary outcome of cognitive functioning (mean change in composite z score±SD: 0·25±0·45 vs. 0·09±0·37, p = 0·03, estimated difference = 0·16 with 95% CI: 0·02-0·30, despite greater training time in the active control condition (mean±SD:56·9 ± 34·6 vs. 37·7 ±23 ·8 hours played, p = 0·006. This study provides Class I evidence that adaptive, computer-based cognitive remediation accessed from home can improve cognitive functioning in MS. This telerehabilitation approach allowed for rapid recruitment and high compliance, and can be readily applied to other neurological conditions associated with cognitive dysfunction.Clinicaltrials.gov NCT02141386.

  3. Cognitive function in multiple sclerosis improves with telerehabilitation: Results from a randomized controlled trial.

    Science.gov (United States)

    Charvet, Leigh E; Yang, Jie; Shaw, Michael T; Sherman, Kathleen; Haider, Lamia; Xu, Jianjin; Krupp, Lauren B

    2017-01-01

    Cognitive impairment affects more than half of all individuals living with multiple sclerosis (MS). We hypothesized that training at home with an adaptive online cognitive training program would have greater cognitive benefit than ordinary computer games in cognitively-impaired adults with MS. This was a double-blind, randomized, active-placebo-controlled trial. Participants with MS were recruited through Stony Brook Medicine and randomly assigned to either the adaptive cognitive remediation (ACR) program or active control of ordinary computer games for 60 hours over 12 weeks. Training was remotely-supervised and delivered through a study-provided laptop computer. A computer generated, blocked stratification table prepared by statistician provided the randomization schedule and condition was assigned by a study technician. The primary outcome, administered by study psychometrician, was measured by change in a neuropsychological composite measure from baseline to study end. An intent-to-treat analysis was employed and missing primary outcome values were imputed via Markov Chain Monte Carlo method. Participants in the ACR (n = 74) vs. active control (n = 61) training program had significantly greater improvement in the primary outcome of cognitive functioning (mean change in composite z score±SD: 0·25±0·45 vs. 0·09±0·37, p = 0·03, estimated difference = 0·16 with 95% CI: 0·02-0·30), despite greater training time in the active control condition (mean±SD:56·9 ± 34·6 vs. 37·7 ±23 ·8 hours played, p = 0·006). This study provides Class I evidence that adaptive, computer-based cognitive remediation accessed from home can improve cognitive functioning in MS. This telerehabilitation approach allowed for rapid recruitment and high compliance, and can be readily applied to other neurological conditions associated with cognitive dysfunction. Clinicaltrials.gov NCT02141386.

  4. Spatial quantum correlations induced by random multiple scattering of quadrature squeezed light

    DEFF Research Database (Denmark)

    Lodahl, Peter

    2007-01-01

    The authors demonstrates that spatial quantum correlations are induced by multiple scattering of quadrature squeezed light through a random medium. As a consequence, light scattered along two different directions by the random medium will not be independent, but be correlated to an extent that ca...... only be described by a quantum mechanical theory for multiple scattering. The spatial quantum correlation is revealed in the fluctuations of the total intensity transmission or reflection through the multiple scattering medium.......The authors demonstrates that spatial quantum correlations are induced by multiple scattering of quadrature squeezed light through a random medium. As a consequence, light scattered along two different directions by the random medium will not be independent, but be correlated to an extent that can...

  5. A random access memory immune to single event upset using a T-Resistor

    Science.gov (United States)

    Ochoa, A. Jr.

    1987-10-28

    In a random access memory cell, a resistance ''T'' decoupling network in each leg of the cell reduces random errors caused by the interaction of energetic ions with the semiconductor material forming the cell. The cell comprises two parallel legs each containing a series pair of complementary MOS transistors having a common gate connected to the node between the transistors of the opposite leg. The decoupling network in each leg is formed by a series pair of resistors between the transistors together with a third resistor interconnecting the junction between the pair of resistors and the gate of the transistor pair forming the opposite leg of the cell. 4 figs.

  6. On solving discrete optimization problems with multiple random elements under general regret functions

    NARCIS (Netherlands)

    Mandal, Pranab K.; Ghosh, D.; Das, S

    2005-01-01

    In this paper we attempt to find least risk solutions for stochastic discrete optimization problems (SDOP) with multiple random elements, where the feasibility of a solution does not depend on the particular values the random elements in the problem take. While the optimal solution, for a linear

  7. On the performance of a code division multiple access scheme with transmit/receive conflicts

    Science.gov (United States)

    Silvester, J. A.

    One of the benefits of spread spectrum is that by assigning each user a different orthogonal signal set, multiple transmissions can occur simultaneously. This possibility is utilized in new access schemes called Code Division Multiple Access (CDMA). The present investigation is concerned with a particular CDMA implementation in which the transmit times for each symbol are exactly determined in a distributed manner such that both sender and receiver know them. In connection with a decision whether to transmit or receive, the loss of a symbol in one of the channels results. The system employs thus a coding technique which permits correct decoding of a codeword even if some constituent symbols are missing or in error. The technique used is Reed Solomon coding. The performance of this system is analyzed, and attention is given to the optimum strategy which should be used in deciding whether to receive or transmit.

  8. A Review on Spectral Amplitude Coding Optical Code Division Multiple Access

    Science.gov (United States)

    Kaur, Navpreet; Goyal, Rakesh; Rani, Monika

    2017-06-01

    This manuscript deals with analysis of Spectral Amplitude Coding Optical Code Division Multiple Access (SACOCDMA) system. The major noise source in optical CDMA is co-channel interference from other users known as multiple access interference (MAI). The system performance in terms of bit error rate (BER) degrades as a result of increased MAI. It is perceived that number of users and type of codes used for optical system directly decide the performance of system. MAI can be restricted by efficient designing of optical codes and implementing them with unique architecture to accommodate more number of users. Hence, it is a necessity to design a technique like spectral direct detection (SDD) technique with modified double weight code, which can provide better cardinality and good correlation property.

  9. Source-Channel Coding Theorems for the Multiple-Access Relay Channe

    CERN Document Server

    Murin, Yonathan; Gündüz, Deniz

    2011-01-01

    Reliable transmission of arbitrarily correlated sources over multiple-access relay channels (MARCs) and multiple-access broadcast relay channels (MABRCs) is considered. In MARCs only the destination is interested in a reconstruction of the sources, while in MABRCs both the relay and the destination want to reconstruct the sources. In addition to arbitrary correlation among the source signals at the users, both the relay and the destination are assumed to have side information correlated with the source signals. Sufficient conditions for reliable communication based on operational separation, as well as necessary conditions on the achievable source-channel rates are characterized. Since operational separation is generally not optimal for MARCs and MABRCs, sufficient conditions for reliable communication using joint source-channel coding schemes based on a combination of the correlation preserving mapping technique with binning are also derived. For correlated sources transmitted over fading Gaussian MARCs and ...

  10. Resistive random access memory and its applications in storage and nonvolatile logic

    Science.gov (United States)

    Zhu, Dongbin; Li, Yi; Shen, Wensheng; Zhou, Zheng; Liu, Lifeng; Zhang, Xing

    2017-07-01

    The resistive random access memory (RRAM) device has been widely studied due to its excellent memory characteristics and great application potential in different fields. In this paper, resistive switching materials, switching mechanism, and memory characteristics of RRAM are discussed. Recent research progress of RRAM in high-density storage and nonvolatile logic application are addressed. Technological trends are also discussed. The resistive random access memory (RRAM) device has been widely studied due to its excellent memory characteristics and great application potential in different fields. In this paper, resistive switching materials, switching mechanism, and memory characteristics of RRAM are discussed. Recent research progress of RRAM in high-density storage and nonvolatile logic application are addressed. Technological trends are also discussed.

  11. Throughput Analysis Model for IEEE 802.11e EDCA with Multiple Access Categories

    Directory of Open Access Journals (Sweden)

    Y. Lee

    2013-08-01

    Full Text Available IEEE 802.11e standard has been specified to support differentiated quality of service (QoS, one of the critical issues on the conventional IEEE 802.11 wireless local area networks (WLANs. Enhanced Distributed Channel Access (EDCA is the fundamental and mandatory contention-based channel access method of IEEE 802.11e, and delivers traffic based on differentiated Access Categories (ACs. A general three dimensional Markov chain model of IEEE 802.11e EDCA for performance analysis is proposed in this paper. The analytical model considers multiple stations with an arbitrary number of different ACs. It also differentiates the contention window (CW sizes and the arbitration interframe spaces (AIFSs, and considers virtual collision mechanism. Based on the model, the saturation throughput of EDCA is derived, and the accuracy of the proposed model is validated via simulations.

  12. Characterization of coded random access with compressive sensing based multi user detection

    DEFF Research Database (Denmark)

    Ji, Yalei; Stefanovic, Cedomir; Bockelmann, Carsten

    2014-01-01

    and is inherently capable to take advantage of the capture effect from the PHY layer. Furthermore, at the PHY layer, compressive sensing based multi-user detection (CS-MUD) is a novel technique that exploits sparsity in multi-user detection to achieve a joint activity and data detection. In this paper, we combine...... coded random access with CS-MUD on the PHY layer and show very promising results for the resulting protocol....

  13. Partial Interference and Its Performance Impact on Wireless Multiple Access Networks

    Directory of Open Access Journals (Sweden)

    Lau WingCheong

    2010-01-01

    Full Text Available To determine the capacity of wireless multiple access networks, the interference among the wireless links must be accurately modeled. In this paper, we formalize the notion of the partial interference phenomenon observed in many recent wireless measurement studies and establish analytical models with tractable solutions for various types of wireless multiple access networks. In particular, we characterize the stability region of IEEE 802.11 networks under partial interference with two potentially unsaturated links numerically. We also provide a closed-form solution for the stability region of slotted ALOHA networks under partial interference with two potentially unsaturated links and obtain a partial characterization of the boundary of the stability region for the general M-link case. Finally, we derive a closed-form approximated solution for the stability region for general M-link slotted ALOHA system under partial interference effects. Based on our results, we demonstrate that it is important to model the partial interference effects while analyzing wireless multiple access networks. This is because such considerations can result in not only significant quantitative differences in the predicted system capacity but also fundamental qualitative changes in the shape of the stability region of the systems.

  14. Polarization division multiple access with polarization modulation for LOS wireless communications

    Directory of Open Access Journals (Sweden)

    Cao Bin

    2011-01-01

    Full Text Available Abstract In this paper, we discuss a potential multiple access and modulation scheme based on polarized states (PS of electromagnetic (EM waves for line-of-sight (LOS communications. The proposed scheme is theoretic different from the existing polar modulation for EDGE and WCDMA systems. We propose the detailed bit representation (modulation and multiple access scheme using PS. Because of the inflexibility of polarization information in the time and frequency domains, as well as independence of frequency and space, the polarization information can be used independently for wireless communications, i.e., another independent resource domain that can be utilized. Due to the independence between the PS and the specific features of signals (such as waveform, bandwidth and data rate, the discussed polarization division multiple access (PDMA and polarization modulation (PM are expected to improve the spectrum utilization effectively. It is proved that the polarization filtering technique can be adopted in the PDMA-PM wireless communications to separate the multiuser signals and demodulate the bit information representing by PS for desired user. Some theoretical analysis is done to demonstrate the feasibility of the proposed scheme, and the simulation results are made to evaluate the performance of the suggested system.

  15. Complementarity between entanglement-assisted and quantum distributed random access code

    Science.gov (United States)

    Hameedi, Alley; Saha, Debashis; Mironowicz, Piotr; Pawłowski, Marcin; Bourennane, Mohamed

    2017-05-01

    Collaborative communication tasks such as random access codes (RACs) employing quantum resources have manifested great potential in enhancing information processing capabilities beyond the classical limitations. The two quantum variants of RACs, namely, quantum random access code (QRAC) and the entanglement-assisted random access code (EARAC), have demonstrated equal prowess for a number of tasks. However, there do exist specific cases where one outperforms the other. In this article, we study a family of 3 →1 distributed RACs [J. Bowles, N. Brunner, and M. Pawłowski, Phys. Rev. A 92, 022351 (2015), 10.1103/PhysRevA.92.022351] and present its general construction of both the QRAC and the EARAC. We demonstrate that, depending on the function of inputs that is sought, if QRAC achieves the maximal success probability then EARAC fails to do so and vice versa. Moreover, a tripartite Bell-type inequality associated with the EARAC variants reveals the genuine multipartite nonlocality exhibited by our protocol. We conclude with an experimental realization of the 3 →1 distributed QRAC that achieves higher success probabilities than the maximum possible with EARACs for a number of tasks.

  16. Random Access Memories: A New Paradigm for Target Detection in High Resolution Aerial Remote Sensing Images.

    Science.gov (United States)

    Zou, Zhengxia; Shi, Zhenwei

    2018-03-01

    We propose a new paradigm for target detection in high resolution aerial remote sensing images under small target priors. Previous remote sensing target detection methods frame the detection as learning of detection model + inference of class-label and bounding-box coordinates. Instead, we formulate it from a Bayesian view that at inference stage, the detection model is adaptively updated to maximize its posterior that is determined by both training and observation. We call this paradigm "random access memories (RAM)." In this paradigm, "Memories" can be interpreted as any model distribution learned from training data and "random access" means accessing memories and randomly adjusting the model at detection phase to obtain better adaptivity to any unseen distribution of test data. By leveraging some latest detection techniques e.g., deep Convolutional Neural Networks and multi-scale anchors, experimental results on a public remote sensing target detection data set show our method outperforms several other state of the art methods. We also introduce a new data set "LEarning, VIsion and Remote sensing laboratory (LEVIR)", which is one order of magnitude larger than other data sets of this field. LEVIR consists of a large set of Google Earth images, with over 22 k images and 10 k independently labeled targets. RAM gives noticeable upgrade of accuracy (an mean average precision improvement of 1% ~ 4%) of our baseline detectors with acceptable computational overhead.

  17. Randomization-based adjustment of multiple treatment hazard ratios for covariates with missing data.

    Science.gov (United States)

    Lam, Diana; Koch, Gary G; Preisser, John S; Saville, Benjamin R; Hussey, Michael A

    2017-01-01

    Clinical trials are designed to compare treatment effects when applied to samples from the same population. Randomization is used so that the samples are not biased with respect to baseline covariates that may influence the efficacy of the treatment. We develop randomization-based covariance adjustment methodology to estimate the log hazard ratios and their confidence intervals of multiple treatments in a randomized clinical trial with time-to-event outcomes and missingness among the baseline covariates. The randomization-based covariance adjustment method is a computationally straight-forward method for handling missing baseline covariate values.

  18. Randomized controlled trials in central vascular access devices: A scoping review

    Science.gov (United States)

    Keogh, Samantha; Rickard, Claire M.

    2017-01-01

    Background Randomized controlled trials evaluate the effectiveness of interventions for central venous access devices, however, high complication rates remain. Scoping reviews map the available evidence and demonstrate evidence deficiencies to focus ongoing research priorities. Method A scoping review (January 2006–December 2015) of randomized controlled trials evaluating the effectiveness of interventions to improve central venous access device outcomes; including peripherally inserted central catheters, non-tunneled, tunneled and totally implanted venous access catheters. MeSH terms were used to undertake a systematic search with data extracted by two independent researchers, using a standardized data extraction form. Results In total, 178 trials were included (78 non-tunneled [44%]; 40 peripherally inserted central catheters [22%]; 20 totally implanted [11%]; 12 tunneled [6%]; 6 non-specified [3%]; and 22 combined device trials [12%]). There were 119 trials (68%) involving adult participants only, with 18 (9%) pediatric and 20 (11%) neonatal trials. Insertion-related themes existed in 38% of trials (67 RCTs), 35 RCTs (20%) related to post-insertion patency, with fewer trials on infection prevention (15 RCTs, 8%), education (14RCTs, 8%), and dressing and securement (12 RCTs, 7%). There were 46 different study outcomes reported, with the most common being infection outcomes (161 outcomes; 37%), with divergent definitions used for catheter-related bloodstream and other infections. Conclusion More high quality randomized trials across central venous access device management are necessary, especially in dressing and securement and patency. These can be encouraged by having more studies with multidisciplinary team involvement and consumer engagement. Additionally, there were extensive gaps within population sub-groups, particularly in tunneled devices, and in pediatrics and neonates. Finally, outcome definitions need to be unified for results to be meaningful and

  19. Access to Electronic Personal Health Records Among Patients With Multiple Chronic Conditions: A Secondary Data Analysis.

    Science.gov (United States)

    Greenberg, Alexandra J; Falisi, Angela L; Finney Rutten, Lila J; Chou, Wen-Ying Sylvia; Patel, Vaishali; Moser, Richard P; Hesse, Bradford W

    2017-06-02

    In the United States, national incentives for offering access to electronic personal health records (ePHRs) through electronic means are geared toward creating a culture of patient engagement. One group of patients who stand to benefit from online access to ePHRs is the growing population with multiple chronic conditions (MCC). However, little is known about the current availability and use of ePHRs and patient portals among those managing MCC. The aim was to determine the associations between number of chronic conditions and sociodemographic characteristics and usage of ePHRs, and to assess how the public's use of ePHRs varies across subpopulations, including those with MCC. This study used data collected from the 2014 Health Information National Trends Survey (HINTS), and assessed differences in use of ePHRs between those with and without MCC (N=3497) using multiple logistic regression techniques. Variables associated with health care systems (insurance status, having a regular provider) and patient-reported self-efficacy were included in the statistical models. Those with MCC (n=1555) had significantly higher odds of accessing their records three or more times in the past year compared to those reporting no chronic conditions (n=1050; OR 2.46, 95% CI 1.37-4.45), but the overall percentage of those with MCC using ePHRs remained low (371 of 1529 item respondents, 25.63% weighted). No difference in odds of accessing their records was found between those reporting one chronic condition (n=892) and those reporting none (n=1050; OR 1.02, 95% CI 0.66-1.58). Significant differences in odds of accessing ePHRs were seen between income and age groups (P<.001 and P=.05, respectively), and by whether respondents had a regular provider (P=.03). We conclude that ePHRs provide a unique opportunity to enhance MCC patient self-management, but additional effort is needed to ensure that these patients are able to access their ePHRs. An increase in availability of patient access to

  20. Central or peripheral catheters for initial venous access of ICU patients: a randomized controlled trial.

    Science.gov (United States)

    Ricard, Jean-Damien; Salomon, Laurence; Boyer, Alexandre; Thiery, Guillaume; Meybeck, Agnes; Roy, Carine; Pasquet, Blandine; Le Mière, Eric; Dreyfuss, Didier

    2013-09-01

    The vast majority of ICU patients require some form of venous access. There are no evidenced-based guidelines concerning the use of either central or peripheral venous catheters, despite very different complications. It remains unknown which to insert in ICU patients. We investigated the rate of catheter-related insertion or maintenance complications in two strategies: one favoring the central venous catheters and the other peripheral venous catheters. Multicenter, controlled, parallel-group, open-label randomized trial. Three French ICUs. Adult ICU patients with equal central or peripheral venous access requirement. Patients were randomized to receive central venous catheters or peripheral venous catheters as initial venous access. The primary endpoint was the rate of major catheter-related complications within 28 days. Secondary endpoints were the rate of minor catheter-related complications and a composite score-assessing staff utilization and time spent to manage catheter insertions. Analysis was intention to treat. We randomly assigned 135 patients to receive a central venous catheter and 128 patients to receive a peripheral venous catheter. Major catheter-related complications were greater in the peripheral venous catheter than in the central venous catheter group (133 vs 87, respectively, p=0.02) although none of those was life threatening. Minor catheter-related complications were 201 with central venous catheters and 248 with peripheral venous catheters (p=0.06). 46% (60/128) patients were managed throughout their ICU stay with peripheral venous catheters only. There were significantly more peripheral venous catheter-related complications per patient in patients managed solely with peripheral venous catheter than in patients that received peripheral venous catheter and at least one central venous catheter: 1.92 (121/63) versus 1.13 (226/200), pcentral venous catheter-related complications per patient between patients initially randomized to peripheral

  1. FODA: a novel efficient multiple access protocol for highly dynamic self-organizing networks

    Science.gov (United States)

    Li, Hantao; Liu, Kai; Zhang, Jun

    2005-11-01

    Based on the concept of contention reservation for polling transmission and collision prevention strategy for collision resolution, a fair on-demand access (FODA) protocol for supporting node mobility and multihop architecture in highly dynamic self-organizing networks is proposed. In the protocol, a distributed clustering network architecture formed by self-organizing algorithm and a main idea of reserving channel resources to get polling service are adopted, so that the hidden terminal (HT) and exposed terminal (ET) problems existed in traffic transmission due to multihop architecture and wireless transmission can be eliminated completely. In addition, an improved collision prevention scheme based on binary countdown algorithm (BCA), called fair collision prevention (FCP) algorithm, is proposed to greatly eliminate unfair phenomena existed in contention access of newly active ordinary nodes and completely resolve access collisions. Finally, the performance comparison of the FODA protocol with carrier sense multiple access with collision avoidance (CSMA/CA) and polling protocols by OPNET simulation are presented. Simulation results show that the FODA protocol can overcome the disadvantages of CSMA/CA and polling protocols, and achieve higher throughput, lower average message delay and less average message dropping rate.

  2. Delay-limited capacity of fading multiple access and broadcast channels in the low power regime

    KAUST Repository

    Rezki, Zouheir

    2015-09-11

    We study delay-limited (also called zero-outage) capacity region of the fading multi-access channel (MAC) with Gaussian noise and perfect channel state information (CSI) at the receiver and at the transmitters (CSI-TR), in the low-power regime. We show that for fading channels where the MAC capacity region is strictly positive, it has a multidimensional rectangle structure and thus is simply characterized by single user capacity points. More specifically, we show that at low power, the boundary surface of the capacity region shrinks to a single point corresponding to the sum-rate maximizer and that the coordinates of this point coincide with single user capacity bounds. Using the duality of the Gaussian MAC and broadcast channels (BC), we show that time-sharing (or time division multiple access (TDMA)) is asymptotically optimal. © 2015 IEEE.

  3. Phenomenological analysis of random telegraph noise in amorphous TiOx-based bipolar resistive switching random access memory devices.

    Science.gov (United States)

    Lee, Jung-Kyu; Lee, Ju-Wan; Bae, Jong-Ho; Park, Jinwon; Chung, Sung-Woong; Roh, Jae Sung; Hong, Sung-Joo; Lee, Jong-Ho

    2012-07-01

    As dimensions of resistive random access memories (RRAMs) devices continue to shrink, the low-frequency noise of nanoscale devices has become increasingly important in evaluating the device reliability. Thus, we investigated random telegraph noise (RTN) caused by capture and emission of an electron at traps. We physically analyzed capture and emission processes through systematic measurements of amorphous TiOx (alpha-TiOx)-based bipolar RRAMs. RTNs were observed during high-resistance state (HRS) in most devices. However, discrete switching behavior was scarcely observed in low-resistance state (LRS) as most of traps in the alpha-TiOx were filled with mobile ions such as O2- in LRS. The capture and emission processes of an electron at traps are largely divided into two groups: (1) both capture and emission processes are mainly affected by electric field; and (2) one of the capture and emission processes is only influenced by the thermal process. This paper provides fundamental physics required to understand the mechanism of RTNs in alpha-TiOx-based bipolar RRAMs.

  4. Impact of patient access to Internet health records on glaucoma medication: randomized controlled trial.

    Science.gov (United States)

    Kashiwagi, Kenji; Tsukahara, Shigeo

    2014-01-15

    Glaucoma is one of the leading causes of blindness. Reduction of intraocular pressure is the only proven way to prevent progression of glaucomatous optic neuropathy. The majority of glaucoma patients need to use antiglaucoma ophthalmic solutions over the course of their life. Thus, good adherence and persistency of glaucoma treatment are important factors for better glaucoma care. The purpose of this study was to investigate the impact of an Internet-based glaucoma care support system on glaucoma medication use. Patients were randomly divided into two groups. The non-Internet access (NIA) group consisted of patients who had access to the Internet-based glaucoma care support system during the 4-year period only when they were examined by ophthalmologists. The Internet access (IA) group consisted of patients who had the same Internet-based glaucoma care support system access as the NIA group for the first 2 years following enrollment but who were also given free access to the glaucoma care support system for the remaining 2 years. Changes in glaucoma medication use were investigated. In total, 81 patients in the IA group and 90 patients in the NIA group satisfied the study protocol. The number of antiglaucoma ophthalmic solutions used during the study period significantly increased in the NIA group (PInternet access significantly shifted from an increasing intraocular pressure trend to a decreasing trend in the IA group (P=.002) among the patients who did not have any medication changes. Allowing patients to browse their medical data may reduce the use and improve the effectiveness of glaucoma medication. UMIN-CTR Clinical Trial Number: UMIN000006982; https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&type=summary&recptno=R000008238&language=E (Archived by WebCite at http://www.webcitation.org/6MRPQeEAv).

  5. Analysis of multiple access techniques in multi-satellite and multi-spot mobile satellite systems

    Science.gov (United States)

    Corazza, Giovanni E.; Ferrarelli, Carlo; Vatalaro, Francesco

    1995-01-01

    In this paper the analysis of mobile satellite systems adopting constellations of multi-spot satellites over non-geostationary orbits is addressed. A link design procedure is outlined, taking into account system spectrum efficiency, probability of bit error and outage probability. A semi-analytic approach to the evaluation of outage probability in the presence of fading and imperfect power control is described, and applied to single channel per carrier (SCPC) and code division multiple access (CDMA) techniques. Some results are shown for the Globalstar, Iridium and Odyssey orbital configurations.

  6. A Code Phase Division Multiple Access (CPDMA) technique for VSAT satellite communications

    Science.gov (United States)

    Bruno, R.; Mcomber, R.; Weinberg, A.

    1991-01-01

    A reference concept and implementation relevant to the application of Code Phase Division Multiple Access (CPDMA) to a high capacity satellite communication system providing 16 Kbps single hop channels between Very Small Aperture Terminals (VSAT's) is described. The description includes a potential implementation of an onboard CPDMA bulk demodulator/converter utilizing programmable charge coupled device (CCD) technology projected to be available in the early 1990's. A high level description of the system architecture and operations, identification of key functional and performance requirements of the system elements, and analysis results of end-to-end system performance relative to key figures of merit such as spectral efficiency are also provided.

  7. Correlation between static random access memory power-up state and transistor variation

    Science.gov (United States)

    Takeuchi, Kiyoshi; Mizutani, Tomoko; Saraya, Takuya; Shinohara, Hirofumi; Kobayashi, Masaharu; Hiramoto, Toshiro

    2017-04-01

    The correlation between the static random access memory (SRAM) power-up state (i.e., state 0 or 1 immediately after the power supply is turned on) and cell transistor variation is systematically studied by circuit simulations and mismatch space partitioning. It is revealed that, while both the mismatches of pFETs (pull-up) and nFETs (pull-down and access) contribute, their relative importance changes depending on the voltage ramping speed. The static retention noise margin well correlates with the power-up state only if the ramping speed is sufficiently low. Otherwise, pull-up transistor mismatch dominates the power-up state determination owing to the interference of capacitive current and asymmetrical capacitive coupling of the storage nodes to the ground and power supply.

  8. AQUa: An Adaptive Framework for Compression of Sequencing Quality Scores with Random Access Functionality.

    Science.gov (United States)

    Paridaens, Tom; Van Wallendael, Glenn; De Neve, Wesley; Lambert, Peter

    2017-09-25

    The past decade has seen the introduction of new technologies that significantly lowered the cost of genome sequencing. As a result, the amount of genomic data that must be stored and transmitted is increasing exponentially. To mitigate storage and transmission issues, we introduce a framework for lossless compression of quality scores. This paper proposes AQUa, an adaptive framework for lossless compression of quality scores. To compress these quality scores, AQUa makes use of a configurable set of coding tools, extended with a Context-Adaptive Binary Arithmetic Coding scheme (CABAC). When benchmarking AQUa against generic single-pass compressors, file sizes are reduced by up to 38.49% when comparing with GNU Gzip and by up to 6.48% when comparing with 7-Zip at the Ultra Setting, while still providing support for random access. When comparing AQUa with the purpose-built, single-pass, and state-of-the-art compressor SCALCE, which does not support random access, file sizes are reduced by up to 21.14%. When comparing AQUa with the purpose-built, dual-pass, and state-of-the-art compressor QVZ, which does not support random access, file sizes are larger by 6.42% to 33.47%. However, for one test file, the file size is 0.38% smaller, illustrating the strength of our single-pass compression framework. This work has been spurred by the current activity on genomic information representation (MPEG-G) within the ISO/IEC SC29/WG11 technical committee. The software is available on Github: https://github.com/tparidae/AQUa. Tom Paridaens (tom.paridaens@ugent.be).

  9. Online Resource to Promote Vocational Interests Among Job Seekers With Multiple Sclerosis: A Randomized Controlled Trial in Australia.

    Science.gov (United States)

    Dorstyn, Diana; Roberts, Rachel; Murphy, Gregory; Kneebone, Ian; Craig, Ashley; Migliorini, Christine

    2017-09-18

    To provide a preliminary evaluation of the effectiveness of an online resource for job seekers with multiple sclerosis (MS). Randomized controlled design. Community-dwelling cohort. Adults (N = 97) with relapsing-remitting or progressive MS were randomly assigned to one of two groups. Forty-seven accessed an email delivered, 7 module resource, Work and MS, over a 4 week period. Waitlist control participants (n=50) were offered the opportunity to access Work and MS 4 weeks postenrollment. Primary outcomes focused on vocational interests (My Vocational Situation Scale) and self-efficacy in job-seeking activities (Job-Procurement Self Efficacy Scale). Secondary outcomes focused on perceived workplace difficulties (Multiple Sclerosis Work Difficulties Questionnaire [MSWDQ]), optimism (Life Orientation Test - Revised), and mood (Patient Health Questionnaire-9). Intention-to-treat analyses revealed pre-post gains: participants who accessed Work and MS reported improved confidence in their career goals (My Vocational Situation Scale g=.55; 95% confidence interval [CI], .14-.96; P=.008) and positively reappraised potential workplace difficulties (MSWDQ g range, .42-.47; P range, .023-.042). The effect on job self-efficacy was not significant, but changed in the expected direction (g=.17; 95% CI, -.23 to .57; P=.409). Completer data revealed larger, significant effect estimates (g range, .52-.64; P range, .009-.035). Findings provide preliminary support for the utility of a job information resource, Work and MS, to augment existing employment services. The results also suggest the need to test employment-ready interventions in a larger study population. This might include the addition of online peer support to increase intervention compliance. Copyright © 2017 American Congress of Rehabilitation Medicine. All rights reserved.

  10. Achievable Rate of a Cognitive MIMO Multiple Access Channel With Multi-Secondary Users

    KAUST Repository

    Sboui, Lokman

    2015-03-01

    We study the secondary sum-rate of an underlay cognitive multiple access channel consisting of a primary user and multiple secondary users (SUs) communicating with a common destination. We propose a particular linear precoding and SU selection scheme that maximize the cognitive sum-rate. This scheme is based on space alignment strategy allowing SUs to share the spectrum without interfering with each other. We derive the optimal power allocation for each selected SU after applying perfect or imperfect successive interference cancellation. Numerical results show that the proposed scheme provides a significant sum-rate improvement as the number of SUs increases. In addition, it achieves almost the same performance as an exhaustive search selection, mainly in low and high power ranges. © 1997-2012 IEEE.

  11. Nonvolatile transtance change random access memory based on magnetoelectric P(VDF-TrFE)/Metglas heterostructures

    Science.gov (United States)

    Lu, Peipei; Shang, Dashan; Shen, Jianxin; Chai, Yisheng; Yang, Chuansen; Zhai, Kun; Cong, Junzhuang; Shen, Shipeng; Sun, Young

    2016-12-01

    Transtance change random access memory (TCRAM) is a type of nonvolatile memory based on the nonlinear magnetoelectric coupling effects of multiferroics. In this work, ferroelectric P(VDF-TrFE) thin films were prepared on Metglas foil substrates by the sol-gel technique to form multiferroic heterostructures. The magnetoelectric voltage coefficient of the heterostructure can be switched reproducibly to different levels between positive and negative values by applying selective electric-field pulses. Compared with bulk multiferroic heterostructures, the polarization switching voltage was reduced to 7 V. Our facile technological approach enables this organic magnetoelectric heterostructure as a promising candidate for the applications in multilevel TCRAM devices.

  12. Paging memory from random access memory to backing storage in a parallel computer

    Science.gov (United States)

    Archer, Charles J; Blocksome, Michael A; Inglett, Todd A; Ratterman, Joseph D; Smith, Brian E

    2013-05-21

    Paging memory from random access memory (`RAM`) to backing storage in a parallel computer that includes a plurality of compute nodes, including: executing a data processing application on a virtual machine operating system in a virtual machine on a first compute node; providing, by a second compute node, backing storage for the contents of RAM on the first compute node; and swapping, by the virtual machine operating system in the virtual machine on the first compute node, a page of memory from RAM on the first compute node to the backing storage on the second compute node.

  13. Recovery of failed resistive switching random access memory devices by a low-temperature supercritical treatment

    Science.gov (United States)

    Du, Xiaoqin; Wu, Xiaojing; Chang, Ting-Chang; Chang, Kuan-Chang; Pan, Chih-Hung; Wu, Cheng-Hsien; Lin, Yu-Shuo; Chen, Po-Hsun; Zhang, Shengdong; Sze, Simon M.

    2017-06-01

    The successful recovery of resistive switching random access memory (RRAM) devices that have undergone switching failure is achieved by introducing a low-temperature supercritical-fluid process that passivates the switching layer. These failed RRAM devices, which are incapable of switching between high- and low-resistance states, were treated with supercritical carbon dioxide with pure water at 120 °C for 1 h. After the treatment, the devices became operational again and showed excellent current-voltage (I-V) characteristics and reliability as before. On the basis of the current conduction mechanism fitting results, we propose a model to explain the phenomenon.

  14. Generalized Encoding CRDSA: Maximizing Throughput in Enhanced Random Access Schemes for Satellite

    Directory of Open Access Journals (Sweden)

    Manlio Bacco

    2014-12-01

    Full Text Available This work starts from the analysis of the literature about the Random Access protocols with contention resolution, such as Contention Resolution Diversity Slotted Aloha (CRDSA, and introduces a possible enhancement, named Generalized Encoding Contention Resolution Diversity Slotted Aloha (GE-CRDSA. The GE-CRDSA aims at improving the aggregated throughput when the system load is less than 50%, playing on the opportunity of transmitting an optimal combination of information and parity packets frame by frame. This paper shows the improvement in terms of throughput, by performing traffic estimation and adaptive choice of information and parity rates, when a satellite network undergoes a variable traffic load profile.

  15. Thermodynamics of Phase Transitions and Bipolar Filamentary Switching in Resistive Random-Access Memory

    Science.gov (United States)

    Karpov, V. G.; Niraula, D.; Karpov, I. V.; Kotlyar, R.

    2017-08-01

    We present a phenomenological theory of bipolar filamentary resistive random-access memory describing the commonly observed features of their current-voltage characteristics. Our approach follows the approach of a thermodynamic theory developed earlier for chalcogenide memory and threshold switches and largely independent of their microscopic details. It explains, without adjustable parameters, such features as the domains of filament formation and switching, voltage-independent current in set and current-independent voltage in reset regimes, the relation between the set and reset voltages, filament resistance independent of its length, etc. Furthermore, it expresses the observed features through the material and circuitry parameters, thus paving the way to device improvements.

  16. An establishment of vascular access through superior vena cava for a patient with multiple central venous stenosis or occlusion.

    Science.gov (United States)

    Diao, Yong Shu; Feng, Yan Huan; Liu, Chun Cheng; Cui, Tian Lei; Fu, Ping

    2016-05-01

    The patency of vascular access is of vital importance to dialysis patients. Access dysfunction is largely caused by vessel stenosis and thrombosis. Nephrologists usually find themselves helpless when all treatments fail and the vascular access seems to have exhausted. Here we report a successful establishment of vascular access through superior vena cava for a critical patient with multiple central venous stenosis or occlusion. To our knowledge, it is the first case ever reported on the successful establishment of vascular access through superior vena cava under such a complicated condition of vascular exhaustion.

  17. Research on the reliability of friction system under combined additive and multiplicative random excitations

    Science.gov (United States)

    Sun, Jiaojiao; Xu, Wei; Lin, Zifei

    2018-01-01

    In this paper, the reliability of a non-linearly damped friction oscillator under combined additive and multiplicative Gaussian white noise excitations is investigated. The stochastic averaging method, which is usually applied to the research of smooth system, has been extended to the study of the reliability of non-smooth friction system. The results indicate that the reliability of friction system can be improved by Coulomb friction and reduced by random excitations. In particular, the effect of the external random excitation on the reliability is larger than the effect of the parametric random excitation. The validity of the analytical results is verified by the numerical results.

  18. Development of the Average Likelihood Function for Code Division Multiple Access (CDMA) Using BPSK and QPSK Symbols

    Science.gov (United States)

    2015-01-01

    DEVELOPMENT OF THE AVERAGE LIKELIHOOD FUNCTION FOR CODE DIVISION MULTIPLE ACCESS ( CDMA ) USING BPSK AND QPSK SYMBOLS JANUARY 2015...To) OCT 2013 – OCT 2014 4. TITLE AND SUBTITLE DEVELOPMENT OF THE AVERAGE LIKELIHOOD FUNCTION FOR CODE DIVISION MULTIPLE ACCESS ( CDMA ) USING BPSK...effort titled “Average Likelihood Methods for CDMA ”. In this report, we extend the derivation of the average likelihood function for three additional

  19. Stability of multiple access network control schemes with carrier sensing and exponential backoff

    Science.gov (United States)

    Barany, Ernest; Krupa, Maciej

    2006-05-01

    A new approach to determine the stability of multiple access network control schemes is presented. A “busy” network (the precise meaning of the term “busy” will be presented in the text) is modelled as a switched single-server hybrid dynamical system whose switching laws are stochastic and are based on typical multiple access network control protocols such as ALOHA and ethernet. The techniques are used to compute the critical ratio of traffic production per network node to total available bandwidth that ensures that data packets will not accumulate unboundedly in waiting queues at each node. This is a measure of stability of the network and is an emergent, global, property determined by decentralized, autonomous behavior of each node. The behavior of each individual node is regarded as “microscopic” and the collective behavior of the network as a whole are emergent consequences of such microscopic laws. The results follow from the stationary distribution property of ergodic Markov chains.

  20. Efficient traffic grooming with dynamic ONU grouping for multiple-OLT-based access network

    Science.gov (United States)

    Zhang, Shizong; Gu, Rentao; Ji, Yuefeng; Wang, Hongxiang

    2015-12-01

    Fast bandwidth growth urges large-scale high-density access scenarios, where the multiple Passive Optical Networking (PON) system clustered deployment can be adopted as an appropriate solution to fulfill the huge bandwidth demands, especially for a future 5G mobile network. However, the lack of interaction between different optical line terminals (OLTs) results in part of the bandwidth resources waste. To increase the bandwidth efficiency, as well as reduce bandwidth pressure at the edge of a network, we propose a centralized flexible PON architecture based on Time- and Wavelength-Division Multiplexing PON (TWDM PON). It can provide flexible affiliation for optical network units (ONUs) and different OLTs to support access network traffic localization. Specifically, a dynamic ONU grouping algorithm (DGA) is provided to obtain the minimal OLT outbound traffic. Simulation results show that DGA obtains an average 25.23% traffic gain increment under different OLT numbers within a small ONU number situation, and the traffic gain will increase dramatically with the increment of the ONU number. As the DGA can be deployed easily as an application running above the centralized control plane, the proposed architecture can be helpful to improve the network efficiency for future traffic-intensive access scenarios.

  1. Recombinant azurin-CdSe/ZnS hybrid structures for nanoscale resistive random access memory device.

    Science.gov (United States)

    Yagati, Ajay Kumar; Kim, Sang-Uk; Lee, Taek; Min, Junhong; Choi, Jeong-Woo

    2017-04-15

    In the present study, we developed a biohybrid material composed of recombinant azurin and CdSe-ZnS quantum dot to perform as a resistive random access memory (ReRAM) device. Site specific amino acid sequences were introduced in azurin to bind with the surface of CdSe-ZnS nanoparticle allowing the formation of a hybrid and voltage-driven switching enabled to develop a resistive random access memory (ReRAM) device. The analytical measurements confirmed that the azurin and CdSe-ZnS nanoparticles were well conjugated and formed into a single hybrid. Further, reversible, bistable switching along with repeatable writing-reading-erasing processes on individual azurin/CdSe-ZnS hybrid at nanoscale was achieved on the hybrid device. The device was programmed tested for 50 cycles with an ON/OFF ratio and measured to be of three orders of magnitude. The developed device shown good stability and repeatability and operates at low voltages thus makes it promising candidate for future memory device applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. On the time varying horizontal water velocity of single, multiple, and random gravity wave trains

    NARCIS (Netherlands)

    Wells, D.R.

    1964-01-01

    In this dissertation some characteristics of the horizontal water velocity for single, multiple, and random gravity wave trains are studied. This work consists of two parts, an analogue study and hydraulic measurements. An important aspect in this work is to suggest the horizontal water velocity

  3. A randomized, placebo-controlled trial of natalizumab for relapsing multiple sclerosis.

    NARCIS (Netherlands)

    Polman, C.H.; O'Connor, P.W.; Havrdova, E.; Hutchinson, M.; Kappos, L.; Miller, D.H.; Phillips, J.T.; Lublin, F.D.; Giovannoni, G.; Wajgt, A.; Toal, M.; Lynn, F.; Panzara, M.A.; Sandrock, A.W.

    2006-01-01

    BACKGROUND: Natalizumab is the first alpha4 integrin antagonist in a new class of selective adhesion-molecule inhibitors. We report the results of a two-year phase 3 trial of natalizumab in patients with relapsing multiple sclerosis. METHODS: Of a total of 942 patients, 627 were randomly assigned to

  4. A randomized crossover study of bee sting therapy for multiple sclerosis

    NARCIS (Netherlands)

    Wesselius, T; Heersema, DJ; Mostert, JP; Heerings, M; Admiraal-Behloul, F; Talebian, A; van Buchem, MA; De Keyser, J

    2005-01-01

    Background: Bee sting therapy is increasingly used to treat patients with multiple sclerosis (MS) in the belief that it can stabilize or ameliorate the disease. However, there are no clinical studies to justify its use. Methods: In a randomized, crossover study, we assigned 26 patients with

  5. Boosting the FM-Index on the GPU: Effective Techniques to Mitigate Random Memory Access.

    Science.gov (United States)

    Chacón, Alejandro; Marco-Sola, Santiago; Espinosa, Antonio; Ribeca, Paolo; Moure, Juan Carlos

    2015-01-01

    The recent advent of high-throughput sequencing machines producing big amounts of short reads has boosted the interest in efficient string searching techniques. As of today, many mainstream sequence alignment software tools rely on a special data structure, called the FM-index, which allows for fast exact searches in large genomic references. However, such searches translate into a pseudo-random memory access pattern, thus making memory access the limiting factor of all computation-efficient implementations, both on CPUs and GPUs. Here, we show that several strategies can be put in place to remove the memory bottleneck on the GPU: more compact indexes can be implemented by having more threads work cooperatively on larger memory blocks, and a k-step FM-index can be used to further reduce the number of memory accesses. The combination of those and other optimisations yields an implementation that is able to process about two Gbases of queries per second on our test platform, being about 8 × faster than a comparable multi-core CPU version, and about 3 × to 5 × faster than the FM-index implementation on the GPU provided by the recently announced Nvidia NVBIO bioinformatics library.

  6. RSARF: Prediction of residue solvent accessibility from protein sequence using random forest method

    KAUST Repository

    Ganesan, Pugalenthi

    2012-01-01

    Prediction of protein structure from its amino acid sequence is still a challenging problem. The complete physicochemical understanding of protein folding is essential for the accurate structure prediction. Knowledge of residue solvent accessibility gives useful insights into protein structure prediction and function prediction. In this work, we propose a random forest method, RSARF, to predict residue accessible surface area from protein sequence information. The training and testing was performed using 120 proteins containing 22006 residues. For each residue, buried and exposed state was computed using five thresholds (0%, 5%, 10%, 25%, and 50%). The prediction accuracy for 0%, 5%, 10%, 25%, and 50% thresholds are 72.9%, 78.25%, 78.12%, 77.57% and 72.07% respectively. Further, comparison of RSARF with other methods using a benchmark dataset containing 20 proteins shows that our approach is useful for prediction of residue solvent accessibility from protein sequence without using structural information. The RSARF program, datasets and supplementary data are available at http://caps.ncbs.res.in/download/pugal/RSARF/. - See more at: http://www.eurekaselect.com/89216/article#sthash.pwVGFUjq.dpuf

  7. Color coded multiple access scheme for bidirectional multiuser visible light communications in smart home technologies

    Science.gov (United States)

    Tiwari, Samrat Vikramaditya; Sewaiwar, Atul; Chung, Yeon-Ho

    2015-10-01

    In optical wireless communications, multiple channel transmission is an attractive solution to enhancing capacity and system performance. A new modulation scheme called color coded multiple access (CCMA) for bidirectional multiuser visible light communications (VLC) is presented for smart home applications. The proposed scheme uses red, green and blue (RGB) light emitting diodes (LED) for downlink and phosphor based white LED (P-LED) for uplink to establish a bidirectional VLC and also employs orthogonal codes to support multiple users and devices. The downlink transmission for data user devices and smart home devices is provided using red and green colors from the RGB LEDs, respectively, while uplink transmission from both types of devices is performed using the blue color from P-LEDs. Simulations are conducted to verify the performance of the proposed scheme. It is found that the proposed bidirectional multiuser scheme is efficient in terms of data rate and performance. In addition, since the proposed scheme uses RGB signals for downlink data transmission, it provides flicker-free illumination that would lend itself to multiuser VLC system for smart home applications.

  8. Adaptation of AMO-FBMC-OQAM in optical access network for accommodating asynchronous multiple access in OFDM-based uplink transmission

    Science.gov (United States)

    Jung, Sun-Young; Jung, Sang-Min; Han, Sang-Kook

    2015-01-01

    Exponentially expanding various applications in company with proliferation of mobile devices make mobile traffic exploded annually. For future access network, bandwidth efficient and asynchronous signals converged transmission technique is required in optical network to meet a huge bandwidth demand, while integrating various services and satisfying multiple access in perceived network resource. Orthogonal frequency division multiplexing (OFDM) is highly bandwidth efficient parallel transmission technique based on orthogonal subcarriers. OFDM has been widely studied in wired-/wireless communication and became a Long term evolution (LTE) standard. Consequently, OFDM also has been actively researched in optical network. However, OFDM is vulnerable frequency and phase offset essentially because of its sinc-shaped side lobes, therefore tight synchronism is necessary to maintain orthogonality. Moreover, redundant cyclic prefix (CP) is required in dispersive channel. Additionally, side lobes act as interference among users in multiple access. Thus, it practically hinders from supporting integration of various services and multiple access based on OFDM optical transmission In this paper, adaptively modulated optical filter bank multicarrier system with offset QAM (AMO-FBMC-OQAM) is introduced and experimentally investigated in uplink optical transmission to relax multiple access interference (MAI), while improving bandwidth efficiency. Side lobes are effectively suppressed by using FBMC, therefore the system becomes robust to path difference and imbalance among optical network units (ONUs), which increase bandwidth efficiency by reducing redundancy. In comparison with OFDM, a signal performance and an efficiency of frequency utilization are improved in the same experimental condition. It enables optical network to effectively support heterogeneous services and multiple access.

  9. Analysis of the TDRS multiple access system for possible use as an attitude control system sensor

    Science.gov (United States)

    Blevins, Bruce Allyn; Sank, Victor J.

    1993-01-01

    A member of the constellation of TDR satellites (TDRS) has experienced a failure of its prime earth sensor. Failure of the remaining earth sensor could result in the inability of the satellite to control its attitude and provide user services. Loss of the satellite would be a serious event. The multiple access (MA) antenna array on the TDRS has been proposed for use as a backup sensor for the attitude control system. This paper describes our analysis of the performance of the MA array as an interferometer used for accurate attitude determination. A least squares fit of a plane to the MA phase information appears to represent the TDRS body roll and pitch within about 0.1 deg. This is sufficient for SGL pointing and MA and SSA user services. Analytic improvements that include ionospheric correction may yield sufficient accuracy for KSA user services.

  10. Isolated user security enhancement in optical code division multiple access network against eavesdropping

    Science.gov (United States)

    Jyoti, Vishav; Kaler, Rajinder Singh

    2012-09-01

    A novel virtual user system is modeled for enhancing the security of an optical code division multiple access (OCDMA) network. Although the OCDMA system implementing code shift keying (CSK) is secure against a conventional power detector, it is susceptible to differential eavesdropping. An analytical framework is developed for the CSK-OCDMA system to show eavesdropper's code interception performance for a single transmitting user in the presence of a virtual user. It is shown that the eavesdropper's probability of correct bit interception decreases from 7.1×10-1 to 1.85×10-5 with the inclusion of the virtual user. Furthermore, the results confirm that the proposed virtual user scheme increases the confidentiality of the CSK-OCDMA system and outperforms the conventional OCDMA scheme in terms of security.

  11. System and method for integrating and accessing multiple data sources within a data warehouse architecture

    Science.gov (United States)

    Musick, Charles R [Castro Valley, CA; Critchlow, Terence [Livermore, CA; Ganesh, Madhaven [San Jose, CA; Slezak, Tom [Livermore, CA; Fidelis, Krzysztof [Brentwood, CA

    2006-12-19

    A system and method is disclosed for integrating and accessing multiple data sources within a data warehouse architecture. The metadata formed by the present method provide a way to declaratively present domain specific knowledge, obtained by analyzing data sources, in a consistent and useable way. Four types of information are represented by the metadata: abstract concepts, databases, transformations and mappings. A mediator generator automatically generates data management computer code based on the metadata. The resulting code defines a translation library and a mediator class. The translation library provides a data representation for domain specific knowledge represented in a data warehouse, including "get" and "set" methods for attributes that call transformation methods and derive a value of an attribute if it is missing. The mediator class defines methods that take "distinguished" high-level objects as input and traverse their data structures and enter information into the data warehouse.

  12. Characterization and Optimization of LDPC Codes for the 2-User Gaussian Multiple Access Channel

    Directory of Open Access Journals (Sweden)

    Declercq David

    2007-01-01

    Full Text Available We address the problem of designing good LDPC codes for the Gaussian multiple access channel (MAC. The framework we choose is to design multiuser LDPC codes with joint belief propagation decoding on the joint graph of the 2-user case. Our main result compared to existing work is to express analytically EXIT functions of the multiuser decoder with two different approximations of the density evolution. This allows us to propose a very simple linear programming optimization for the complicated problem of LDPC code design with joint multiuser decoding. The stability condition for our case is derived and used in the optimization constraints. The codes that we obtain for the 2-user case are quite good for various rates, especially if we consider the very simple optimization procedure.

  13. Analysis of Coded FHSS Systems with Multiple Access Interference over Generalized Fading Channels

    Directory of Open Access Journals (Sweden)

    Salam A. Zummo

    2009-02-01

    Full Text Available We study the effect of interference on the performance of coded FHSS systems. This is achieved by modeling the physical channel in these systems as a block fading channel. In the derivation of the bit error probability over Nakagami fading channels, we use the exact statistics of the multiple access interference (MAI in FHSS systems. Due to the mathematically intractable expression of the Rician distribution, we use the Gaussian approximation to derive the error probability of coded FHSS over Rician fading channel. The effect of pilot-aided channel estimation is studied for Rician fading channels using the Gaussian approximation. From this, the optimal hopping rate in coded FHSS is approximated. Results show that the performance loss due to interference increases as the hopping rate decreases.

  14. A Bayesian Game-Theoretic Approach for Distributed Resource Allocation in Fading Multiple Access Channels

    Directory of Open Access Journals (Sweden)

    Gaoning He

    2010-01-01

    Full Text Available A Bayesian game-theoretic model is developed to design and analyze the resource allocation problem in K-user fading multiple access channels (MACs, where the users are assumed to selfishly maximize their average achievable rates with incomplete information about the fading channel gains. In such a game-theoretic study, the central question is whether a Bayesian equilibrium exists, and if so, whether the network operates efficiently at the equilibrium point. We prove that there exists exactly one Bayesian equilibrium in our game. Furthermore, we study the network sum-rate maximization problem by assuming that the users coordinate according to a symmetric strategy profile. This result also serves as an upper bound for the Bayesian equilibrium. Finally, simulation results are provided to show the network efficiency at the unique Bayesian equilibrium and to compare it with other strategies.

  15. Multiple random walks on complex networks: A harmonic law predicts search time

    Science.gov (United States)

    Weng, Tongfeng; Zhang, Jie; Small, Michael; Hui, Pan

    2017-05-01

    We investigate multiple random walks traversing independently and concurrently on complex networks and introduce the concept of mean first parallel passage time (MFPPT) to quantify their search efficiency. The mean first parallel passage time represents the expected time required to find a given target by one or some of the multiple walkers. We develop a general theory that allows us to calculate the MFPPT analytically. Interestingly, we find that the global MFPPT follows a harmonic law with respect to the global mean first passage times of the associated walkers. Remarkably, when the properties of multiple walkers are identical, the global MFPPT decays in a power law manner with an exponent of unity, irrespective of network structure. These findings are confirmed by numerical and theoretical results on various synthetic and real networks. The harmonic law reveals a universal principle governing multiple random walks on networks that uncovers the contribution and role of the combined walkers in a target search. Our paradigm is also applicable to a broad range of random search processes.

  16. Multiple Imputation of a Randomly Censored Covariate Improves Logistic Regression Analysis.

    Science.gov (United States)

    Atem, Folefac D; Qian, Jing; Maye, Jacqueline E; Johnson, Keith A; Betensky, Rebecca A

    2016-01-01

    Randomly censored covariates arise frequently in epidemiologic studies. The most commonly used methods, including complete case and single imputation or substitution, suffer from inefficiency and bias. They make strong parametric assumptions or they consider limit of detection censoring only. We employ multiple imputation, in conjunction with semi-parametric modeling of the censored covariate, to overcome these shortcomings and to facilitate robust estimation. We develop a multiple imputation approach for randomly censored covariates within the framework of a logistic regression model. We use the non-parametric estimate of the covariate distribution or the semiparametric Cox model estimate in the presence of additional covariates in the model. We evaluate this procedure in simulations, and compare its operating characteristics to those from the complete case analysis and a survival regression approach. We apply the procedures to an Alzheimer's study of the association between amyloid positivity and maternal age of onset of dementia. Multiple imputation achieves lower standard errors and higher power than the complete case approach under heavy and moderate censoring and is comparable under light censoring. The survival regression approach achieves the highest power among all procedures, but does not produce interpretable estimates of association. Multiple imputation offers a favorable alternative to complete case analysis and ad hoc substitution methods in the presence of randomly censored covariates within the framework of logistic regression.

  17. Multiplicative random regression model for heterogeneous variance adjustment in genetic evaluation for milk yield in Simmental.

    Science.gov (United States)

    Lidauer, M H; Emmerling, R; Mäntysaari, E A

    2008-06-01

    A multiplicative random regression (M-RRM) test-day (TD) model was used to analyse daily milk yields from all available parities of German and Austrian Simmental dairy cattle. The method to account for heterogeneous variance (HV) was based on the multiplicative mixed model approach of Meuwissen. The variance model for the heterogeneity parameters included a fixed region x year x month x parity effect and a random herd x test-month effect with a within-herd first-order autocorrelation between test-months. Acceleration of variance model solutions after each multiplicative model cycle enabled fast convergence of adjustment factors and reduced total computing time significantly. Maximum Likelihood estimation of within-strata residual variances was enhanced by inclusion of approximated information on loss in degrees of freedom due to estimation of location parameters. This improved heterogeneity estimates for very small herds. The multiplicative model was compared with a model that assumed homogeneous variance. Re-estimated genetic variances, based on Mendelian sampling deviations, were homogeneous for the M-RRM TD model but heterogeneous for the homogeneous random regression TD model. Accounting for HV had large effect on cow ranking but moderate effect on bull ranking.

  18. Capacity Bounds for the Gaussian IM-DD Optical Multiple-Access Channel

    KAUST Repository

    Chaaban, Anas

    2017-03-18

    Optical wireless communications (OWC) is a promising technology for closing the mismatch between the growing number of connected devices and the limited wireless network capabilities. Similar to downlink, uplink can also benefit from OWC for establishing connectivity between such devices and an optical access point. In this context, the incoherent intensitymodulation and direct-detection (IM-DD) scheme is desirable in practice. Hence, it is important to understand the fundamental limits of communication rates over an OWC uplink employing IM-DD, i.e., the channel capacity. This uplink, modeled as a Gaussian multiple-access channel (MAC) for indoors OWC, is studied in this paper, under the IM-DD constraints which form the main difference with the standard Gaussian MAC commonly studied in the radio-frequency context. Capacity region outer and inner bounds for this channel are derived. The bounds are fairly close at high signal-to-noise ratio (SNR), where a truncated- Gaussian input distribution achieves the capacity region within a constant gap. Furthermore, the bounds coincide at low SNR showing the optimality of on-off keying combined with successive cancellation decoding in this regime. At moderate SNR, an optimized uniformly-spaced discrete input distribution achieves fairly good performance.

  19. Chemical insight into origin of forming-free resistive random-access memory devices

    KAUST Repository

    Wu, X.

    2011-09-29

    We demonstrate the realization of a forming-step free resistive random access memory (RRAM) device using a HfOx/TiOx/HfOx/TiOxmultilayer structure, as a replacement for the conventional HfOx-based single layer structure. High-resolution transmission electron microscopy (HRTEM), along with electron energy loss spectroscopy(EELS)analysis has been carried out to identify the distribution and the role played by Ti in the RRAM stack. Our results show that Ti out-diffusion into the HfOx layer is the chemical cause of forming-free behavior. Moreover, the capability of Ti to change its ionic state in HfOx eases the reduction-oxidation (redox) reaction, thus lead to the RRAM devices performance improvements.

  20. Surface effects of electrode-dependent switching behavior of resistive random-access memory

    KAUST Repository

    Ke, Jr Jian

    2016-09-26

    The surface effects of ZnO-based resistive random-access memory (ReRAM) were investigated using various electrodes. Pt electrodes were found to have better performance in terms of the device\\'s switching functionality. A thermodynamic model of the oxygen chemisorption process was proposed to explain this electrode-dependent switching behavior. The temperature-dependent switching voltage demonstrates that the ReRAM devices fabricated with Pt electrodes have a lower activation energy for the chemisorption process, resulting in a better resistive switching performance. These findings provide an in-depth understanding of electrode-dependent switching behaviors and can serve as design guidelines for future ReRAM devices.

  1. Bipolar resistive switching characteristics in tantalum nitride-based resistive random access memory devices

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myung Ju; Jeon, Dong Su; Park, Ju Hyun; Kim, Tae Geun, E-mail: tgkim1@korea.ac.kr [School of Electrical Engineering, Anam-dong 5ga, Sungbuk-gu, Seoul 136-701 (Korea, Republic of)

    2015-05-18

    This paper reports the bipolar resistive switching characteristics of TaN{sub x}-based resistive random access memory (ReRAM). The conduction mechanism is explained by formation and rupture of conductive filaments caused by migration of nitrogen ions and vacancies; this mechanism is in good agreement with either Ohmic conduction or the Poole-Frenkel emission model. The devices exhibit that the reset voltage varies from −0.82 V to −0.62 V, whereas the set voltage ranges from 1.01 V to 1.30 V for 120 DC sweep cycles. In terms of reliability, the devices exhibit good retention (>10{sup 5 }s) and pulse-switching endurance (>10{sup 6} cycles) properties. These results indicate that TaN{sub x}-based ReRAM devices have a potential for future nonvolatile memory devices.

  2. Single event upset in static random access memories in atmospheric neutron environments

    CERN Document Server

    Arita, Y; Ogawa, I; Kishimoto, T

    2003-01-01

    Single-event upsets (SEUs) in a 0.4 mu m 4Mbit complementary metal oxide semiconductor (CMOS) static random access memory (SRAM) were investigated in various atmospheric neutron environments at sea level, at an altitude of 2612 m mountain, at an altitude of commercial airplane, and at an underground depth of 476m. Neutron-induced SEUs increase with the increase in altitude. For a device with a borophosphosilicate glass (BPSG) film, SEU rates induced by thermal neutrons increase with the decrease in the cell charge of a memory cell. A thermal neutron-induced SEU is significant in SRAMs with a small cell charge. With the conditions of small cell charge, thermal neutron-induced SEUs account for 60% or more of the total neutron-induced SEUs. The SEU rate induced by atmospheric thermal neutrons can be estimated by an acceleration test using sup 2 sup 5 sup 2 Cf. (author)

  3. A stochastic control approach to Slotted-ALOHA random access protocol

    Science.gov (United States)

    Pietrabissa, Antonio

    2013-12-01

    ALOHA random access protocols are distributed protocols based on transmission probabilities, that is, each node decides upon packet transmissions according to a transmission probability value. In the literature, ALOHA protocols are analysed by giving necessary and sufficient conditions for the stability of the queues of the node buffers under a control vector (whose elements are the transmission probabilities assigned to the nodes), given an arrival rate vector (whose elements represent the rates of the packets arriving in the node buffers). The innovation of this work is that, given an arrival rate vector, it computes the optimal control vector by defining and solving a stochastic control problem aimed at maximising the overall transmission efficiency, while keeping a grade of fairness among the nodes. Furthermore, a more general case in which the arrival rate vector changes in time is considered. The increased efficiency of the proposed solution with respect to the standard ALOHA approach is evaluated by means of numerical simulations.

  4. Role of an encapsulating layer for reducing resistance drift in phase change random access memory

    Directory of Open Access Journals (Sweden)

    Bo Jin

    2014-12-01

    Full Text Available Phase change random access memory (PCRAM devices exhibit a steady increase in resistance in the amorphous phase upon aging and this resistance drift phenomenon directly affects the device reliability. A stress relaxation model is used here to study the effect of a device encapsulating layer material in addressing the resistance drift phenomenon in PCRAM. The resistance drift can be increased or decreased depending on the biaxial moduli of the phase change material (YPCM and the encapsulating layer material (YELM according to the stress relationship between them in the drift regime. The proposed model suggests that the resistance drift can be effectively reduced by selecting a proper material as an encapsulating layer. Moreover, our model explains that reducing the size of the phase change material (PCM while fully reset and reducing the amorphous/crystalline ratio in PCM help to improve the resistance drift, and thus opens an avenue for highly reliable multilevel PCRAM applications.

  5. Stable switching of resistive random access memory on the nanotip array electrodes

    KAUST Repository

    Tsai, Kun-Tong

    2016-09-13

    The formation/rupture of conducting filaments (CFs) in resistive random access memory (ReRAM) materials tune the electrical conductivities non-volatilely and are largely affected by its material composition [1], internal configurations [2] and external environments [3,4]. Therefore, controlling repetitive formation/rupture of CF as well as the spatial uniformity of formed CF are fundamentally important for improving the resistive switching (RS) performance. In this context, we have shown that by adding a field initiator, typically a textured electrode, both performance and switching uniformity of ReRAMs can be improved dramatically [5]. In addition, despite its promising characteristics, the scalable fabrication and structural homogeneity of such nanostructured electrodes are still lacking or unattainable, making miniaturization of ReRAM devices an exceeding challenge. Here, we employ nanostructured electrode (nanotip arrays, extremely uniform) formed spontaneously via a self-organized process to improve the ZnO ReRAM switching characteristics.

  6. Random-Access Technique for Self-Organization of 5G Millimeter-Wave Cellular Communications

    Directory of Open Access Journals (Sweden)

    Jasper Meynard Arana

    2016-01-01

    Full Text Available The random-access (RA technique is a key procedure in cellular networks and self-organizing networks (SONs, but the overall processing time of this technique in millimeter-wave (mm-wave cellular systems with directional beams is very long because RA preambles (RAPs should be transmitted in all directions of Tx and Rx beams. In this paper, two different types of preambles (RAP-1 and RAP-2 are proposed to reduce the processing time in the RA stage. After analyzing the correlation property, false-alarm probability, and detection probability of the proposed RAPs, we perform simulations to show that the RAP-2 is suitable for RA in mm-wave cellular systems with directional beams because of the smaller processing time and high detection probability in multiuser environments.

  7. A Cloud-Assisted Random Linear Network Coding Medium Access Control Protocol for Healthcare Applications

    Directory of Open Access Journals (Sweden)

    Elli Kartsakli

    2014-03-01

    Full Text Available Relay sensor networks are often employed in end-to-end healthcare applications to facilitate the information flow between patient worn sensors and the medical data center. Medium access control (MAC protocols, based on random linear network coding (RLNC, are a novel and suitable approach to efficiently handle data dissemination. However, several challenges arise, such as additional delays introduced by the intermediate relay nodes and decoding failures, due to channel errors. In this paper, we tackle these issues by adopting a cloud architecture where the set of relays is connected to a coordinating entity, called cloud manager. We propose a cloud-assisted RLNC-based MAC protocol (CLNC-MAC and develop a mathematical model for the calculation of the key performance metrics, namely the system throughput, the mean completion time for data delivery and the energy efficiency. We show the importance of central coordination in fully exploiting the gain of RLNC under error-prone channels.

  8. Spin-transfer torque magnetoresistive random-access memory technologies for normally off computing (invited)

    Science.gov (United States)

    Ando, K.; Fujita, S.; Ito, J.; Yuasa, S.; Suzuki, Y.; Nakatani, Y.; Miyazaki, T.; Yoda, H.

    2014-05-01

    Most parts of present computer systems are made of volatile devices, and the power to supply them to avoid information loss causes huge energy losses. We can eliminate this meaningless energy loss by utilizing the non-volatile function of advanced spin-transfer torque magnetoresistive random-access memory (STT-MRAM) technology and create a new type of computer, i.e., normally off computers. Critical tasks to achieve normally off computers are implementations of STT-MRAM technologies in the main memory and low-level cache memories. STT-MRAM technology for applications to the main memory has been successfully developed by using perpendicular STT-MRAMs, and faster STT-MRAM technologies for applications to the cache memory are now being developed. The present status of STT-MRAMs and challenges that remain for normally off computers are discussed.

  9. Random multiple key streams for encryption with added CBC mode of operation

    Directory of Open Access Journals (Sweden)

    P. Penchalaiah

    2016-09-01

    For the first time, in this paper, we present a construction method to generate multiple random keys from a core-key with highest possible immunity to crack. We are with a particular emphasis on novel technique to secure user data, we have designed a secure and cost effective new cryptosystem called Rbits (Random bits cypher. In different directions we identify that Rbits having highest immunity to crack and presenting various analysis tests in support from this viewpoint and the analyzed results are reported.

  10. Rationale and Design of the Randomized Evaluation of Default Access to Palliative Services (REDAPS) Trial.

    Science.gov (United States)

    Courtright, Katherine R; Madden, Vanessa; Gabler, Nicole B; Cooney, Elizabeth; Small, Dylan S; Troxel, Andrea; Casarett, David; Ersek, Mary; Cassel, J Brian; Nicholas, Lauren Hersch; Escobar, Gabriel; Hill, Sarah H; O'Brien, Dan; Vogel, Mark; Halpern, Scott D

    2016-09-01

    The substantial nationwide investment in inpatient palliative care services stems from their great promise to improve patient-centered outcomes and reduce costs. However, robust experimental evidence of these benefits is lacking. The Randomized Evaluation of Default Access to Palliative Services (REDAPS) study is a pragmatic, stepped-wedge, cluster randomized trial designed to test the efficacy and costs of specialized palliative care consultative services for hospitalized patients with advanced chronic obstructive pulmonary disease, dementia, or end-stage renal disease, as well as the overall effectiveness of ordering such services by default. Additional aims are to identify the types of services that are most beneficial and the types of patients most likely to benefit, including comparisons between ward and intensive care unit patients. We hypothesize that patient-centered outcomes can be improved without increasing costs by simply changing the default option for palliative care consultation from opt-in to opt-out for patients with life-limiting illnesses. Patients aged 65 years or older are enrolled at 11 hospitals using an integrated electronic health record. As a pragmatic trial designed to enroll between 12,000 and 15,000 patients, eligibility is determined using a validated, electronic health record-based algorithm, and all outcomes are captured via the electronic health record and billing systems data. The time at which each hospital transitions from control, opt-in palliative care consultation to intervention, opt-out consultation is randomly assigned. The primary outcome is a composite measure of in-hospital mortality and length of stay. Secondary outcomes include palliative care process measures and clinical and economic outcomes. Clinical trial registered with www.clinicaltrials.gov (NCT02505035).

  11. Kalman Filtering for Discrete Stochastic Systems with Multiplicative Noises and Random Two-Step Sensor Delays

    Directory of Open Access Journals (Sweden)

    Dongyan Chen

    2015-01-01

    Full Text Available This paper is concerned with the optimal Kalman filtering problem for a class of discrete stochastic systems with multiplicative noises and random two-step sensor delays. Three Bernoulli distributed random variables with known conditional probabilities are introduced to characterize the phenomena of the random two-step sensor delays which may happen during the data transmission. By using the state augmentation approach and innovation analysis technique, an optimal Kalman filter is constructed for the augmented system in the sense of the minimum mean square error (MMSE. Subsequently, the optimal Kalman filtering is derived for corresponding augmented system in initial instants. Finally, a simulation example is provided to demonstrate the feasibility and effectiveness of the proposed filtering method.

  12. The cohort multiple randomized controlled trial design: a valid and efficient alternative to pragmatic trials?

    Science.gov (United States)

    van der Velden, Joanne M; Verkooijen, Helena M; Young-Afat, Danny A; Burbach, Johannes Pm; van Vulpen, Marco; Relton, Clare; van Gils, Carla H; May, Anne M; Groenwold, Rolf Hh

    2017-02-01

    Randomized controlled trials (RCTs)-the gold standard for evaluating the effects of medical interventions-are notoriously challenging in terms of logistics, planning and costs. The cohort multiple randomized controlled trial approach is designed to facilitate randomized trials for pragmatic evaluation of (new) interventions and is a promising variation from conventional pragmatic RCTs. In this paper, we evaluate methodological challenges of conducting an RCT within a cohort. We argue that equally valid results can be obtained from trials conducted within cohorts as from pragmatic RCTs. However, whether this design is more efficient compared with conducting a pragmatic RCT depends on the amount and nature of non-compliance in the intervention arm. © The Author 2016; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.

  13. Making working memory work: The effects of extended practice on focus capacity and the processes of updating, forward access, and random access

    OpenAIRE

    Price, John M.; Colflesh, Gregory J. H.; Cerella, John; Verhaeghen, Paul

    2014-01-01

    We investigated the effects of 10 hours of practice on variations of the N-Back task to investigate the processes underlying possible expansion of the focus of attention within working memory. Using subtractive logic, we showed that random access (i.e., Sternberg-like search) yielded a modest effect (a 50% increase in speed) whereas the processes of forward access (i.e., retrieval in order, as in a standard N-Back task) and updating (i.e., changing the contents of working memory) were execute...

  14. 50 nm AlxOy resistive random access memory array program bit error reduction and high temperature operation

    Science.gov (United States)

    Ning, Sheyang; Ogura Iwasaki, Tomoko; Takeuchi, Ken

    2014-01-01

    In order to decrease program bit error rate (BER) of array-level operation in AlxOy resistive random access memory (ReRAM), program BERs are compared by using 4 × 4 basic set and reset with verify methods on multiple 1024-bit-pages in 50 nm, mega-bit class ReRAM arrays. Further, by using an optimized reset method, 8.5% total BER reduction is obtained after 104 write cycles due to avoiding under-reset or weak reset and ameliorating over-reset caused wear-out. Then, under-set and over-set are analyzed by tuning the set word line voltage (VWL) of ±0.1 V. Moderate set current shows the best total BER. Finally, 2000 write cycles are applied at 125 and 25 °C, respectively. Reset BER increases 28.5% at 125 °C whereas set BER has little difference, by using the optimized reset method. By applying write cycles over a 25 to 125 to 25 °C temperature variation, immediate reset BER change can be found after the temperature transition.

  15. RADB: Random Access with Differentiated Barring for Latency-Constrained Applications in NB-IoT Network

    OpenAIRE

    Miao, Yiming; Tian, Yuanwen; Cheng, Jingjing; Hossain, M. Shamim; Ghoneim, Ahmed

    2018-01-01

    With the development of LPWA (Low Power Wide Area) technology, the emerging NB-IoT (Narrowband Internet of Things) technology is becoming popular with wide area and low-data-rate services. In order to achieve objectives such as huge amount of connection and wide area coverage within NB-IoT, the problem of network congestion generated by random access of numerous devices should be solved. In this paper, we first introduce the background of NB-IoT and investigate the research on random access o...

  16. Interference-Assisted Techniques for Transmission and Multiple Access in Optical Communications

    Science.gov (United States)

    Guan, Xun

    Optical communications can be in wired or wireless form. Fiber optics communication (FOC) connects transmitters and receivers with optical fiber. Benefiting from its high bandwidth, low cost per volume and stability, it gains a significant market share in long-haul networks, access networks and data centers. Meanwhile, optical wireless communication (OWC) is also emerging as a crucial player in the communication market. In OWC, free-space optical communication (FSO) and visible light communication (VLC) are being studied and commercially deployed extensively. Interference is a common phenomenon in multi-user communication systems. In both FOC and OWC, interference has long been treated as a detrimental effect. However, it could also be beneficial to system applications. The effort of harnessing interference has spurred numerous innovations. Interesting examples are physical-layer network coding (PNC) and non-orthogonal multiple access (NOMA). The first part of this thesis in on the topic of PNC. PNC was firstly proposed in wireless communication to improve the throughput of a two-way relay network (TWRN). As a variation of network coding (NC), PNC turns the common channel interference (CCI) as a natural network coding operation. In this thesis, PNC is introduced into optical communication. Three schemes are proposed in different scenarios. Firstly, PNC is applied to a coherent optical orthogonal frequency division multiplexing (CO-OFDM) system so as to improve the throughput of the multicast network. The optical signal to noise ratio (OSNR) penalty is quite low. Secondly, we investigate the application of PNC in an OFDM passive optical network (OFDM-PON) supporting heterogeneous services. It is found that only minor receiver power penalties are observed to realize PNC-based virtual private networks (VPN), both in the wired service part and the wireless service part in an OFDM-PON with heterogeneous services. Thirdly, we innovate relay-based visible light

  17. Comparing cluster-level dynamic treatment regimens using sequential, multiple assignment, randomized trials: Regression estimation and sample size considerations.

    Science.gov (United States)

    NeCamp, Timothy; Kilbourne, Amy; Almirall, Daniel

    2017-08-01

    Cluster-level dynamic treatment regimens can be used to guide sequential treatment decision-making at the cluster level in order to improve outcomes at the individual or patient-level. In a cluster-level dynamic treatment regimen, the treatment is potentially adapted and re-adapted over time based on changes in the cluster that could be impacted by prior intervention, including aggregate measures of the individuals or patients that compose it. Cluster-randomized sequential multiple assignment randomized trials can be used to answer multiple open questions preventing scientists from developing high-quality cluster-level dynamic treatment regimens. In a cluster-randomized sequential multiple assignment randomized trial, sequential randomizations occur at the cluster level and outcomes are observed at the individual level. This manuscript makes two contributions to the design and analysis of cluster-randomized sequential multiple assignment randomized trials. First, a weighted least squares regression approach is proposed for comparing the mean of a patient-level outcome between the cluster-level dynamic treatment regimens embedded in a sequential multiple assignment randomized trial. The regression approach facilitates the use of baseline covariates which is often critical in the analysis of cluster-level trials. Second, sample size calculators are derived for two common cluster-randomized sequential multiple assignment randomized trial designs for use when the primary aim is a between-dynamic treatment regimen comparison of the mean of a continuous patient-level outcome. The methods are motivated by the Adaptive Implementation of Effective Programs Trial which is, to our knowledge, the first-ever cluster-randomized sequential multiple assignment randomized trial in psychiatry.

  18. Transparent mediation-based access to multiple yeast data sources using an ontology driven interface.

    Science.gov (United States)

    Briache, Abdelaali; Marrakchi, Kamar; Kerzazi, Amine; Navas-Delgado, Ismael; Rossi Hassani, Badr D; Lairini, Khalid; Aldana-Montes, José F

    2012-01-25

    Saccharomyces cerevisiae is recognized as a model system representing a simple eukaryote whose genome can be easily manipulated. Information solicited by scientists on its biological entities (Proteins, Genes, RNAs...) is scattered within several data sources like SGD, Yeastract, CYGD-MIPS, BioGrid, PhosphoGrid, etc. Because of the heterogeneity of these sources, querying them separately and then manually combining the returned results is a complex and time-consuming task for biologists most of whom are not bioinformatics expert. It also reduces and limits the use that can be made on the available data. To provide transparent and simultaneous access to yeast sources, we have developed YeastMed: an XML and mediator-based system. In this paper, we present our approach in developing this system which takes advantage of SB-KOM to perform the query transformation needed and a set of Data Services to reach the integrated data sources. The system is composed of a set of modules that depend heavily on XML and Semantic Web technologies. User queries are expressed in terms of a domain ontology through a simple form-based web interface. YeastMed is the first mediation-based system specific for integrating yeast data sources. It was conceived mainly to help biologists to find simultaneously relevant data from multiple data sources. It has a biologist-friendly interface easy to use. The system is available at http://www.khaos.uma.es/yeastmed/.

  19. Non-Orthogonal Multiple Access for Large-Scale 5G Networks: Interference Aware Design

    KAUST Repository

    Ali, Konpal S.

    2017-09-18

    Non-orthogonal multiple access (NOMA) is promoted as a key component of 5G cellular networks. As the name implies, NOMA operation introduces intracell interference (i.e., interference arising within the cell) to the cellular operation. The intracell interference is managed by careful NOMA design (e.g., user clustering and resource allocation) along with successive interference cancellation. However, most of the proposed NOMA designs are agnostic to intercell interference (i.e., interference from outside the cell), which is a major performance limiting parameter in 5G networks. This article sheds light on the drastic negative-impact of intercell interference on the NOMA performance and advocates interference-aware NOMA design that jointly accounts for both intracell and intercell interference. To this end, a case study for fair NOMA operation is presented and intercell interference mitigation techniques for NOMA networks are discussed. This article also investigates the potential of integrating NOMA with two important 5G transmission schemes, namely, full duplex and device-to-device communication. This is important since the ambitious performance defined by the 3rd Generation Partnership Project (3GPP) for 5G is foreseen to be realized via seamless integration of several new technologies and transmission techniques.

  20. On the Tradeoff Between Multiuser Diversity and Training Overhead in Multiple Access Channels

    CERN Document Server

    Scarlett, Jonathan; Dey, Subhrakanti

    2011-01-01

    We consider a single antenna narrowband multiple access channel with a large number of users, in which training sequences are sent to the base station one at a time and the user estimated to be the strongest is scheduled to transmit. In such a system, there is an inherent trade-off between training overhead and the amount of multiuser diversity achieved. Considering a lower bound on the ergodic sum capacity with channel uncertainty under an average total power constraint, we optimize the length of the training sequences, average transmit power during training, and number of users K considered for transmission in each coherence block. Assuming a block fading model with block length L and independent Rayleigh distributed channel gains, we derive closed form expressions for the optimal proportion of both time and power spent on training in terms of K and L. Considering the behavior of the system as L grows large, we derive second order expressions for each of the optimal parameters in terms of L, as well as the ...

  1. An Ultrasonic Multiple-Access Ranging Core Based on Frequency Shift Keying Towards Indoor Localization

    Directory of Open Access Journals (Sweden)

    Laurent Segers

    2015-07-01

    Full Text Available This paper describes a new approach and implementation methodology for indoor ranging based on the time difference of arrival using code division multiple access with ultrasound signals. A novel implementation based on a field programmable gate array using finite impulse response filters and an optimized correlation demodulator implementation for ultrasound orthogonal signals is developed. Orthogonal codes are modulated onto ultrasound signals using frequency shift keying with carrier frequencies of 24.5 kHz and 26 kHz. This implementation enhances the possibilities for real-time, embedded and low-power tracking of several simultaneous transmitters. Due to the high degree of parallelism offered by field programmable gate arrays, up to four transmitters can be tracked simultaneously. The implementation requires at most 30% of the available logic gates of a Spartan-6 XC6SLX45 device and is evaluated on accuracy and precision through several ranging topologies. In the first topology, the distance between one transmitter and one receiver is evaluated. Afterwards, ranging analyses are applied between two simultaneous transmitters and one receiver. Ultimately, the position of the receiver against four transmitters using trilateration is also demonstrated. Results show enhanced distance measurements with distances ranging from a few centimeters up to 17 m, while keeping a centimeter-level accuracy.

  2. An Ultrasonic Multiple-Access Ranging Core Based on Frequency Shift Keying Towards Indoor Localization.

    Science.gov (United States)

    Segers, Laurent; Van Bavegem, David; De Winne, Sam; Braeken, An; Touhafi, Abdellah; Steenhaut, Kris

    2015-07-30

    This paper describes a new approach and implementation methodology for indoor ranging based on the time difference of arrival using code division multiple access with ultrasound signals. A novel implementation based on a field programmable gate array using finite impulse response filters and an optimized correlation demodulator implementation for ultrasound orthogonal signals is developed. Orthogonal codes are modulated onto ultrasound signals using frequency shift keying with carrier frequencies of 24.5 kHz and 26 kHz. This implementation enhances the possibilities for real-time, embedded and low-power tracking of several simultaneous transmitters. Due to the high degree of parallelism offered by field programmable gate arrays, up to four transmitters can be tracked simultaneously. The implementation requires at most 30% of the available logic gates of a Spartan-6 XC6SLX45 device and is evaluated on accuracy and precision through several ranging topologies. In the first topology, the distance between one transmitter and one receiver is evaluated. Afterwards, ranging analyses are applied between two simultaneous transmitters and one receiver. Ultimately, the position of the receiver against four transmitters using trilateration is also demonstrated. Results show enhanced distance measurements with distances ranging from a few centimeters up to 17 m, while keeping a centimeter-level accuracy.

  3. Primary user localisation and uplink resource allocation in orthogonal frequency division multiple access cognitive radio systems

    KAUST Repository

    Nam, Haewoon

    2015-05-21

    In cognitive radio networks, secondary users (SUs) can share spectrum with primary users (PUs) under the condition that no interference is caused to the PUs. To evaluate the interference imposed to the PUs, the cognitive systems discussed in the literature usually assume that the channel state information (CSI) of the link from a secondary transmitter to a primary receiver (interference link) is known at the secondary transmitter. However, this assumption may often be impractical in cognitive radio systems, since the PUs need to be oblivious to the presence of the SUs. The authors first discuss PU localisation and then introduce an uplink resource allocation algorithm for orthogonal frequency division multiple access-based cognitive radio systems, where relative location information between primary and SUs is used instead of CSI of the interference link to estimate the interference. Numerical and simulation results show that it is indeed effective to use location information as a part of resource allocation and thus a near-optimal capacity is achieved. © The Institution of Engineering and Technology 2015.

  4. Comparing multiple competing interventions in the absence of randomized trials using clinical risk-benefit analysis

    Directory of Open Access Journals (Sweden)

    Lazo-Langner Alejandro

    2012-01-01

    Full Text Available Abstract Background To demonstrate the use of risk-benefit analysis for comparing multiple competing interventions in the absence of randomized trials, we applied this approach to the evaluation of five anticoagulants to prevent thrombosis in patients undergoing orthopedic surgery. Methods Using a cost-effectiveness approach from a clinical perspective (i.e. risk benefit analysis we compared thromboprophylaxis with warfarin, low molecular weight heparin, unfractionated heparin, fondaparinux or ximelagatran in patients undergoing major orthopedic surgery, with sub-analyses according to surgery type. Proportions and variances of events defining risk (major bleeding and benefit (thrombosis averted were obtained through a meta-analysis and used to define beta distributions. Monte Carlo simulations were conducted and used to calculate incremental risks, benefits, and risk-benefit ratios. Finally, net clinical benefit was calculated for all replications across a range of risk-benefit acceptability thresholds, with a reference range obtained by estimating the case fatality rate - ratio of thrombosis to bleeding. Results The analysis showed that compared to placebo ximelagatran was superior to other options but final results were influenced by type of surgery, since ximelagatran was superior in total knee replacement but not in total hip replacement. Conclusions Using simulation and economic techniques we demonstrate a method that allows comparing multiple competing interventions in the absence of randomized trials with multiple arms by determining the option with the best risk-benefit profile. It can be helpful in clinical decision making since it incorporates risk, benefit, and personal risk acceptance.

  5. Design and protocol of a randomized multiple behavior change trial: Make Better Choices 2 (MBC2).

    Science.gov (United States)

    Pellegrini, Christine A; Steglitz, Jeremy; Johnston, Winter; Warnick, Jennifer; Adams, Tiara; McFadden, H G; Siddique, Juned; Hedeker, Donald; Spring, Bonnie

    2015-03-01

    Suboptimal diet and inactive lifestyle are among the most prevalent preventable causes of premature death. Interventions that target multiple behaviors are potentially efficient; however the optimal way to initiate and maintain multiple health behavior changes is unknown. The Make Better Choices 2 (MBC2) trial aims to examine whether sustained healthful diet and activity change are best achieved by targeting diet and activity behaviors simultaneously or sequentially. Study design approximately 250 inactive adults with poor quality diet will be randomized to 3 conditions examining the best way to prescribe healthy diet and activity change. The 3 intervention conditions prescribe: 1) an increase in fruit and vegetable consumption (F/V+), decrease in sedentary leisure screen time (Sed-), and increase in physical activity (PA+) simultaneously (Simultaneous); 2) F/V+ and Sed- first, and then sequentially add PA+ (Sequential); or 3) Stress Management Control that addresses stress, relaxation, and sleep. All participants will receive a smartphone application to self-monitor behaviors and regular coaching calls to help facilitate behavior change during the 9 month intervention. Healthy lifestyle change in fruit/vegetable and saturated fat intakes, sedentary leisure screen time, and physical activity will be assessed at 3, 6, and 9 months. MBC2 is a randomized m-Health intervention examining methods to maximize initiation and maintenance of multiple healthful behavior changes. Results from this trial will provide insight about an optimal technology supported approach to promote improvement in diet and physical activity. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Energy conservation for fatigue management in multiple sclerosis: a pilot randomized controlled trial.

    Science.gov (United States)

    García Jalón, E Guiomar; Lennon, Sheila; Peoples, Louise; Murphy, Sam; Lowe-Strong, Andrea

    2013-01-01

    To develop and test the feasibility of an energy conservation programme to manage fatigue in multiple sclerosis. A pilot randomized controlled trial. Community setting. People with multiple sclerosis reporting fatigue. An energy conservation programme was compared to a peer support group. Both interventions were delivered in group format with 2-hour sessions once a week for five weeks. Patients' views about the interventions were sought in discussion groups one week post intervention. The primary feasibility outcomes were recruitment and adherence. Other outcome measures were the Fatigue Impact Scale, Fatigue Severity Scale, MS-Impact Scale-29, MS Self-efficacy Scale, Beck's Depression Scale-Fast Screen and Epworth Sleepiness Scale. Outcomes were administered at baseline, post intervention, 6-week and 3-month follow-up. Almost 30% of the people approached to take part in the study did not commit to participation because of transport/time issues. Twenty-three patients took part in the study. Three patients dropped out, one reporting adverse effects. A power calculation indicated that a sample of 56 (28 per group) would be required for a main randomized controlled trial. Patients valued peer support and those in the energy conservation group described the programme as useful, but reported difficulties completing some practice activities. An energy conservation programme in the community is feasible and welcomed by people with multiple sclerosis. However, future research needs to consider longer follow-ups and practical issues to improve recruitment rate by accommodating to patients' needs.

  7. Light therapy for multiple sclerosis-associated fatigue: Study protocol for a randomized controlled trial.

    Science.gov (United States)

    Mateen, Farrah J; Manalo, Natalie C; Grundy, Sara J; Houghton, Melissa A; Hotan, Gladia C; Erickson, Hans; Videnovic, Aleksandar

    2017-09-01

    Fatigue is the most commonly reported symptom among multiple sclerosis (MS) patients, more than a quarter of whom consider fatigue to be their most disabling symptom. However, there are few effective treatment options for fatigue. We aim to investigate whether supplemental exposure to bright white light will reduce MS-associated fatigue. Eligible participants will have clinically confirmed multiple sclerosis based on the revised McDonald criteria (2010) and a score ≥36 on the Fatigue Severity Scale (FSS). Participants will be randomized 1:1 to bright white light (10,000 lux; active condition) or dim red light (therapy. We will perform an intention-to-treat analysis, comparing the active and control groups to assess the postintervention difference in fatigue levels reported on FSS. Secondary outcome measures include change in global VAFS scores during the light therapy and self-reported quality of life in the Multiple Sclerosis Quality of Life-54. We present a study design and rationale for randomizing a nonpharmacological intervention for MS-associated fatigue, using bright light therapy. The study limitations relate to the logistical issues of a self-administered intervention requiring frequent participant self-report in a relapsing condition. Ultimately, light therapy for the treatment of MS-associated fatigue may provide a low-cost, noninvasive, self-administered treatment for one of the most prevalent and burdensome symptoms experienced by people with MS.

  8. Cognitive behavioural therapy in multiple sclerosis: a randomized controlled pilot study of acceptance and commitment therapy.

    Science.gov (United States)

    Nordin, Linda; Rorsman, Ia

    2012-01-01

    The aim of this study was to design a trial that could evaluate the effect of acceptance and commitment therapy as a group-intervention for multiple sclerosis patients with psychological distress. Randomized controlled trial with assessment at pretreatment, end of treatment, and at 3-month follow-up. Multiple sclerosis outpatients with elevated symptoms of anxiety and/or depression (n = 21). Patients were randomly assigned to acceptance and commitment therapy or relaxation training. Both treatments consisted of 5 sessions over 15 weeks containing didactic sessions, group discussions, and exercises. Outcome was assessed by self-rated symptoms of anxiety, depression, and a measure of acceptance. At 3-month follow-up, the relaxation training group had a significant decline in anxiety symptoms whereas the acceptance and commitment therapy group showed a maintained improvement in rated acceptance at follow-up. The results reflect the different emphases of the therapies. Acceptance and commitment therapy is aimed at living an active, valued life and increasing acceptance, while relaxation training focuses directly on coping strategies to handle emotional symptoms. The results are preliminary, but supportive of further study of brief group interventions for reducing psychological distress in patients with multiple sclerosis.

  9. Improving cancer patients' knowledge about totally implantable access port: a randomized controlled trial.

    Science.gov (United States)

    Piredda, Michela; Biagioli, Valentina; Giannarelli, Diana; Incletoli, Daniele; Grieco, Francesca; Carassiti, Massimiliano; De Marinis, Maria Grazia

    2016-02-01

    Providing patients with written information about totally implantable access ports (TIAPs) is recommended during the pre-implantation period to reduce anxiety and to help recalling information. No study tested the effectiveness of information about TIAP neither with oral communication nor with booklets. This study aimed at evaluating the effectiveness of an information booklet, alone or together with answers to clarification questions, both in improving patients' short- and long-time knowledge about TIAP and in decreasing patients' physiological indicators of anxiety immediately after TIAP implantation. This is a randomized controlled trial with three parallel groups: group A (n = 34) receiving only the booklet, group B (n = 34) receiving the booklet with answers to clarification questions, and group C (n = 37) receiving routine care. After 3 months, pair comparisons revealed a significant improvement in knowledge of TIAP in each group (p difference in group C compared with groups A (p knowledge about TIAP immediately and at 3 months. Adding answers to clarification questions to the booklet was not more effective than the booklet alone. A well-designed booklet with attention both to scientific content and to communication techniques is useful in improving patients' knowledge about TIAP and reducing anxiety.

  10. Multilevel Thermally Assisted Magnetoresistive Random-Access Memory Based on Exchange-Biased Vortex Configurations

    Science.gov (United States)

    de Araujo, C. I. L.; Alves, S. G.; Buda-Prejbeanu, L. D.; Dieny, B.

    2016-08-01

    A concept of multilevel thermally assisted magnetoresistive random-access memory is proposed and investigated by micromagnetic simulations. The storage cells are magnetic tunnel junctions in which the storage layer is exchange biased and in a vortex configuration. The reference layer is an unpinned soft magnetic layer. The stored information is encoded via the position of the vortex core in the storage layer. This position can be varied along two degrees of freedom: the radius and the in-plane angle. The information is read out from the amplitude and phase of the tunnel magnetoresistance signal obtained by applying a rotating field on the cell without heating the cell. Various configurations are compared in which the soft reference layer consists of either a simple ferromagnetic layer or a synthetic antiferromagnetic sandwich (SAF). Among those, the most practical one comprises a SAF reference layer in which the magnetostatic interaction between the SAF and storage layer is minimized. This type of cell should allow one to store at least 40 different states per cell representing more than five bits per cell.

  11. The effects of slotting, burstiness, and jamming in frequency-hopped random access systems

    Science.gov (United States)

    Clare, L. P.; Sastry, A. R. K.

    A model is defined for a frequency-hopped spread-spectrum system, and performance is derived for the aspects of system variables by both mathematical analysis and simulation. Interference is characterized at both the symbol level and the packet levels. Values for the jamming parameters a, rho(t) and rho(f) that cause maximum degradation in the users' throughput are determined. It is shown that, unlike the case of unspread systems, performance does not depend heavily on the burstiness of the user traffic or on whether slotted operation is used. As the number of frequency bins q increases, the difference in performance between slotted and unslotted operation becomes insignificant. For large q, only slightly less throughput is obtainable when the traffic is bursty as compared with continuous transmission by the users; this fact justifies the consideration of random-access techniques in a spread-spectrum environment. The effect of the jamming pulse length a is closely related to gamma, the amount of interference that a symbol can tolerate. If the jamming pulse length is large, the effect of the jammer is similar to additional user traffic of an equal load.

  12. Quality of resuscitation by first responders using the 'public access resuscitator': a randomized manikin study.

    Science.gov (United States)

    Taelman, Dries G; Huybrechts, Sofie A M; Peersman, Wim; Calle, Paul A; Monsieurs, Koenraad G

    2014-12-01

    The CAREvent Public Access Resuscitator (PAR) is an electronic, oxygen-driven cardiopulmonary resuscitation (CPR) device allowing volume-controlled ventilation with a face mask and guiding the rescuer through the resuscitation with voice prompts and visual indications. We hypothesized that 1 year after initial training, the efficacy of ventilation skills (primary outcome) and compression skills (secondary outcome) by first responders using the PAR would be superior compared with CPR with only a face mask. Seventy-one first responders were randomized to a group using the PAR (n=35) and a control group using only a face mask (n=36). CPR skills were assessed immediately after training and after 3, 7 and 12 months using a Skill Reporter manikin. Differences between groups over time and the interaction between time and groups were assessed using repeated measures models. Results are reported as mean values and number of participants with good ventilation or compression skills. Twelve months after training, there were more PAR users with adequate tidal volume than face mask users. Other ventilations skills did not differ between groups. There were more PAR users with an adequate number of compressions and with good hand position. Skill decay over 12 months did not differ between groups, except for hand position, where no decline was observed in the PAR group. Compared with the face mask, PAR improved tidal volume, compressions per minute and hand position in a manikin setting.

  13. Gate contact resistive random access memory in nano scaled FinFET logic technologies

    Science.gov (United States)

    Hsu, Meng-Yin; Shih, Yi-Hong; Chih, Yue-Der; Lin, Chrong Jung; King, Ya-Chin

    2017-04-01

    A full logic-compatible embedded gate contact resistive random access memory (GC-RRAM) cell in the CMOS FinFET logic process without extra mask or processing steps has been successfully demonstrated for high-density and low-cost logic nonvolatile memory (NVM) applications. This novel GC-RRAM cell is composed of a transition metal oxide from the gate contact plug and interlayer dielectric (ILD) in the middle, and a gate contact and an n-type epitaxial drain terminal as the top and bottom electrodes, respectively. It features low-voltage operation and reset current, compact cell size, and a stable read window. As a promising embedded NVM solution, the compact one transistor and one resistor (1T1R) cell is highly scalable as the technology node progresses. Excellent data retention and cycling capability have also been demonstrated by the reliability testing results. These superior characteristics make GC-RRAM one of a few viable candidates for logic NVM for future FinFET circuits.

  14. Low-power resistive random access memory by confining the formation of conducting filaments

    Directory of Open Access Journals (Sweden)

    Yi-Jen Huang

    2016-06-01

    Full Text Available Owing to their small physical size and low power consumption, resistive random access memory (RRAM devices are potential for future memory and logic applications in microelectronics. In this study, a new resistive switching material structure, TiOx/silver nanoparticles/TiOx/AlTiOx, fabricated between the fluorine-doped tin oxide bottom electrode and the indium tin oxide top electrode is demonstrated. The device exhibits excellent memory performances, such as low operation voltage (<±1 V, low operation power, small variation in resistance, reliable data retention, and a large memory window. The current-voltage measurement shows that the conducting mechanism in the device at the high resistance state is via electron hopping between oxygen vacancies in the resistive switching material. When the device is switched to the low resistance state, conducting filaments are formed in the resistive switching material as a result of accumulation of oxygen vacancies. The bottom AlTiOx layer in the device structure limits the formation of conducting filaments; therefore, the current and power consumption of device operation are significantly reduced.

  15. Effects of Electrodes on the Switching Behavior of Strontium Titanate Nickelate Resistive Random Access Memory

    Directory of Open Access Journals (Sweden)

    Ke-Jing Lee

    2015-10-01

    Full Text Available Strontium titanate nickelate (STN thin films on indium tin oxide (ITO/glass substrate were synthesized using the sol-gel method for resistive random access memory (RRAM applications. Aluminum (Al, titanium (Ti, tungsten (W, gold (Au and platinum (Pt were used as top electrodes in the STN-based RRAM to probe the switching behavior. The bipolar resistive switching behavior of the set and reset voltages is in opposite bias in the Al/STN/ITO and Pt/STN/ITO RRAMs, which can be partly ascribed to the different work functions of top electrodes in the ITO. Analyses of the fitting results and temperature-dependent performances showed that the Al/STN/ITO switching was mainly attributed to the absorption/release of oxygen-based functional groups, whereas the Pt/STN/ITO switching can be associated with the diffusion of metal electrode ions. The Al/STN/ITO RRAM demonstrated a high resistance ratio of >106 between the high-resistance state (HRS and the low-resistance state (LRS, as well as a retention ability of >105 s. Furthermore, the Pt/STN/ITO RRAM displayed a HRS/LRS resistance ratio of >103 and a retention ability of >105 s.

  16. Nonvolatile Resistance Random Access Memory Devices Based on ZnO Nanorod Arrays

    Directory of Open Access Journals (Sweden)

    Liang-Wen Ji

    2015-02-01

    Full Text Available In this paper, a nonvolatile resistance random access memory (RRAM device based on ZnO nanorod arrays has been fabricated and characterized. Vertically aligned ZnO nanorod layers (NRLs were deposited on indium tin oxide (ITO electrodes using a hydrothermal process/ chemical bath deposition (CBD. It can be found the Ag/ZnO NRL/ITO capacitor exhibits bipolar resistive switching behavior. The resistive switching behavior may be related to the oxygen vacancies and/or zinc interstitials confined on the surface of the ZnO NRs, giving rise to the formation of straight and extensible conducting path along each ZnO NR. Furthermore, superior stability in resistive switching characteristics was also observed. Both growing times and annealing times were investigated and annealing was done in oxygen for 3, 6 and 9 minutes at different temperatures. For ZnO nanorods that had been annealed for 6 minutes the forming voltage was about 6.06V, the Set voltage was about 3.25V and the Reset voltage was -2.78V. The original resistance was 7×106Ω. The resistance in the low-resistance state was 108Ω and in the high-resistance state was 2016Ω, the resistance ratio was 18.7.

  17. A Collective Study on Modeling and Simulation of Resistive Random Access Memory.

    Science.gov (United States)

    Panda, Debashis; Sahu, Paritosh Piyush; Tseng, Tseung Yuen

    2018-01-10

    In this work, we provide a comprehensive discussion on the various models proposed for the design and description of resistive random access memory (RRAM), being a nascent technology is heavily reliant on accurate models to develop efficient working designs and standardize its implementation across devices. This review provides detailed information regarding the various physical methodologies considered for developing models for RRAM devices. It covers all the important models reported till now and elucidates their features and limitations. Various additional effects and anomalies arising from memristive system have been addressed, and the solutions provided by the models to these problems have been shown as well. All the fundamental concepts of RRAM model development such as device operation, switching dynamics, and current-voltage relationships are covered in detail in this work. Popular models proposed by Chua, HP Labs, Yakopcic, TEAM, Stanford/ASU, Ielmini, Berco-Tseng, and many others have been compared and analyzed extensively on various parameters. The working and implementations of the window functions like Joglekar, Biolek, Prodromakis, etc. has been presented and compared as well. New well-defined modeling concepts have been discussed which increase the applicability and accuracy of the models. The use of these concepts brings forth several improvements in the existing models, which have been enumerated in this work. Following the template presented, highly accurate models would be developed which will vastly help future model developers and the modeling community.

  18. Improving Access to Online Health Information With Conversational Agents: A Randomized Controlled Experiment.

    Science.gov (United States)

    Bickmore, Timothy W; Utami, Dina; Matsuyama, Robin; Paasche-Orlow, Michael K

    2016-01-04

    Conventional Web-based search engines may be unusable by individuals with low health literacy for finding health-related information, thus precluding their use by this population. We describe a conversational search engine interface designed to allow individuals with low health and computer literacy identify and learn about clinical trials on the Internet. A randomized trial involving 89 participants compared the conversational search engine interface (n=43) to the existing conventional keyword- and facet-based search engine interface (n=46) for the National Cancer Institute Clinical Trials database. Each participant performed 2 tasks: finding a clinical trial for themselves and finding a trial that met prespecified criteria. Results indicated that all participants were more satisfied with the conversational interface based on 7-point self-reported satisfaction ratings (task 1: mean 4.9, SD 1.8 vs mean 3.2, SD 1.8, Phealth literacy failed to find any trials that satisfied the prespecified criteria for task 2 using the conventional search engine interface, whereas 36% (5/14) were successful at this task using the conversational interface (P=.05). Conversational agents can be used to improve accessibility to Web-based searches in general and clinical trials in particular, and can help decrease recruitment bias against disadvantaged populations.

  19. Low-power resistive random access memory by confining the formation of conducting filaments

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yi-Jen; Lee, Si-Chen, E-mail: sclee@ntu.edu.tw [Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Shen, Tzu-Hsien; Lee, Lan-Hsuan [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Wen, Cheng-Yen [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Taiwan Consortium of Emergent Crystalline Materials, Ministry of Science and Technology, Taipei 10617, Taiwan (China)

    2016-06-15

    Owing to their small physical size and low power consumption, resistive random access memory (RRAM) devices are potential for future memory and logic applications in microelectronics. In this study, a new resistive switching material structure, TiO{sub x}/silver nanoparticles/TiO{sub x}/AlTiO{sub x}, fabricated between the fluorine-doped tin oxide bottom electrode and the indium tin oxide top electrode is demonstrated. The device exhibits excellent memory performances, such as low operation voltage (<±1 V), low operation power, small variation in resistance, reliable data retention, and a large memory window. The current-voltage measurement shows that the conducting mechanism in the device at the high resistance state is via electron hopping between oxygen vacancies in the resistive switching material. When the device is switched to the low resistance state, conducting filaments are formed in the resistive switching material as a result of accumulation of oxygen vacancies. The bottom AlTiO{sub x} layer in the device structure limits the formation of conducting filaments; therefore, the current and power consumption of device operation are significantly reduced.

  20. Metal oxide resistive random access memory based synaptic devices for brain-inspired computing

    Science.gov (United States)

    Gao, Bin; Kang, Jinfeng; Zhou, Zheng; Chen, Zhe; Huang, Peng; Liu, Lifeng; Liu, Xiaoyan

    2016-04-01

    The traditional Boolean computing paradigm based on the von Neumann architecture is facing great challenges for future information technology applications such as big data, the Internet of Things (IoT), and wearable devices, due to the limited processing capability issues such as binary data storage and computing, non-parallel data processing, and the buses requirement between memory units and logic units. The brain-inspired neuromorphic computing paradigm is believed to be one of the promising solutions for realizing more complex functions with a lower cost. To perform such brain-inspired computing with a low cost and low power consumption, novel devices for use as electronic synapses are needed. Metal oxide resistive random access memory (ReRAM) devices have emerged as the leading candidate for electronic synapses. This paper comprehensively addresses the recent work on the design and optimization of metal oxide ReRAM-based synaptic devices. A performance enhancement methodology and optimized operation scheme to achieve analog resistive switching and low-energy training behavior are provided. A three-dimensional vertical synapse network architecture is proposed for high-density integration and low-cost fabrication. The impacts of the ReRAM synaptic device features on the performances of neuromorphic systems are also discussed on the basis of a constructed neuromorphic visual system with a pattern recognition function. Possible solutions to achieve the high recognition accuracy and efficiency of neuromorphic systems are presented.

  1. A Collective Study on Modeling and Simulation of Resistive Random Access Memory

    Science.gov (United States)

    Panda, Debashis; Sahu, Paritosh Piyush; Tseng, Tseung Yuen

    2018-01-01

    In this work, we provide a comprehensive discussion on the various models proposed for the design and description of resistive random access memory (RRAM), being a nascent technology is heavily reliant on accurate models to develop efficient working designs and standardize its implementation across devices. This review provides detailed information regarding the various physical methodologies considered for developing models for RRAM devices. It covers all the important models reported till now and elucidates their features and limitations. Various additional effects and anomalies arising from memristive system have been addressed, and the solutions provided by the models to these problems have been shown as well. All the fundamental concepts of RRAM model development such as device operation, switching dynamics, and current-voltage relationships are covered in detail in this work. Popular models proposed by Chua, HP Labs, Yakopcic, TEAM, Stanford/ASU, Ielmini, Berco-Tseng, and many others have been compared and analyzed extensively on various parameters. The working and implementations of the window functions like Joglekar, Biolek, Prodromakis, etc. has been presented and compared as well. New well-defined modeling concepts have been discussed which increase the applicability and accuracy of the models. The use of these concepts brings forth several improvements in the existing models, which have been enumerated in this work. Following the template presented, highly accurate models would be developed which will vastly help future model developers and the modeling community.

  2. Performance of Non-Orthogonal Multiple Access (NOMA) in mmWave wireless communications for 5G networks

    DEFF Research Database (Denmark)

    Marcano, Andrea; Christiansen, Henrik Lehrmann

    2017-01-01

    Among the key technologies that have been identified as capacity boosters for fifth generation - 5G - mobile networks, are millimeter wave (mmWave) transmissions and non-orthogonal multiple access (NOMA). The large amount of spectrum available at mmWave frequencies combined with a more effective...

  3. Channel capacity of TDD-OFDM-MIMO for multiple access points in a wireless single-frequency-network

    DEFF Research Database (Denmark)

    Takatori, Y.; Fitzek, Frank; Tsunekawa, K.

    2005-01-01

    MIMO data transmission scheme, which combines Single-Frequency-Network (SFN) with TDD-OFDM-MIMO applied for wireless LAN networks. In our proposal, we advocate to use SFN for multiple access points (MAP) MIMO data transmission. The goal of this approach is to achieve very high channel capacity in both...

  4. Persons with Multiple Disabilities Use Forehead and Smile Responses to Access or Choose among Technology-Aided Stimulation Events

    Science.gov (United States)

    Lancioni, Giulio E.; Singh, Nirbhay N.; O'Reilly, Mark F.; Sigafoos, Jeff; Alberti, Gloria; Bellini, Domencio; Oliva, Doretta; Boccasini, Adele; La Martire, Maria L.; Signorino, Mario

    2013-01-01

    A variety of technology-aided programs have been developed to help persons with congenital or acquired multiple disabilities access preferred stimuli or choose among stimulus options. The application of those programs may pose problems when the participants have very limited behavior repertoires and are unable to use conventional responses and…

  5. System and Method for Detecting Unauthorized Device Access by Comparing Multiple Independent Spatial-Time Data Sets from Other Devices

    Science.gov (United States)

    Krage, Frederick J. (Inventor); Westmeyer, Paul A. (Inventor); Wertenberg, Russell F. (Inventor); Riegel, Jack F. (Inventor)

    2017-01-01

    An authentication procedure utilizes multiple independent sources of data to determine whether usage of a device, such as a desktop computer, is authorized. When a comparison indicates an anomaly from the base-line usage data, the system, provides a notice that access of the first device is not authorized.

  6. Multiple Intimate Partner Violence Experiences: Knowledge, Access, Utilization and Barriers to Utilization of Resources by Women of the African Diaspora.

    Science.gov (United States)

    Sabri, Bushra; Huerta, Julia; Alexander, Kamila A; St Vil, Noelle M; Campbell, Jacquelyn C; Callwood, Gloria B

    2015-11-01

    This study examined knowledge, access, utilization, and barriers to use of resources among Black women exposed to multiple types of intimate partner violence in Baltimore, Maryland and the U.S. Virgin Islands (USVI). We analyzed quantitative survey data collected by 163 women recruited from primary care, prenatal or family planning clinics in Baltimore and the USVI. In addition we analyzed qualitative data from in-depth interviews with 11 women. Quantitative data were analyzed using descriptive statistics and qualitative data were analyzed using thematic analysis. A substantial proportion of Black women with multiple types of violence experiences lacked knowledge of, did not have access to, and did not use resources. Barriers to resource use were identified at the individual, relationship, and community levels. There is need for programs to develop awareness, promote access and utilization of resources, and eliminate barriers to resource use among abused Black women.

  7. Effectiveness of energy conservation management on fatigue and participation in multiple sclerosis: A randomized controlled trial.

    Science.gov (United States)

    Blikman, Lyan Jm; van Meeteren, Jetty; Twisk, Jos Wr; de Laat, Fred Aj; de Groot, Vincent; Beckerman, Heleen; Stam, Henk J; Bussmann, Johannes Bj

    2017-10-01

    Fatigue is a frequently reported and disabling symptom in multiple sclerosis (MS). To investigate the effectiveness of an individual energy conservation management (ECM) intervention on fatigue and participation in persons with primary MS-related fatigue. A total of 86 severely fatigued and ambulatory adults with a definite diagnosis of MS were randomized in a single-blind, two-parallel-arm randomized clinical trial to the ECM group or the information-only control group in outpatient rehabilitation departments. Blinded assessments were carried out at baseline and at 8, 16, 26 and 52 weeks after randomization. Primary outcomes were fatigue (fatigue subscale of Checklist Individual Strength - CIS20r) and participation (Impact on Participation and Autonomy scale - IPA). Modified intention-to-treat analysis was based on 76 randomized patients (ECM, n = 36; MS nurse, n=40). No significant ECM effects were found for fatigue (overall difference CIS20r between the groups = -0.81; 95% confidence interval (CI), -3.71 to 2.11) or for four out of five IPA domains. An overall unfavourable effect was found in the ECM group for the IPA domain social relations (difference between the groups = 0.19; 95% CI, 0.03 to 0.35). The individual ECM format used in this study did not reduce MS-related fatigue and restrictions in participation more than an information-only control condition.

  8. Conservation laws in coupled multiplicative random arrays lead to $1/f$ noise

    CERN Document Server

    Thurner, S; Teich, M C; Thurner, Stefan; Feurstein, Markus C.; Teich, Malvin C.

    1997-01-01

    We consider the dynamic evolution of a coupled array of N multiplicative random variables. The magnitude of each is constrained by a lower bound w_0 and their sum is conserved. Analytical calculation shows that the simplest case, N=2 and w_0=0, exhibits a Lorentzian spectrum which gradually becomes fractal as w_0 increases. Simulation results for larger $N$ reveal fractal spectra for moderate to high values of w_0 and power-law amplitude fluctuations at all values. The results are applied to estimating the fractal exponents for cochlear-nerve-fiber action-potential sequences with remarkable success, using only two parameters.

  9. Multiple-mode large deflection random response of beams with nonlinear damping subjected to acoustic excitation

    Science.gov (United States)

    Prasad, C. B.; Mei, Chuh

    1987-01-01

    Multiple-mode nonlinear analysis is carried out for beams subjected to acoustic excitation. Effects of both nonlinear damping and large-deflection are included in the analysis in an attempt to explain the experimental phenomena of aircraft panels excited at high sound pressure levels; that is the broadening of the strain response peaks and the increase of modal frequency. An amplitude dependent nonlinear damping model is used in the anlaysis to study the effects and interactions of multiple modes, nonlinear stiffness and nonlinear damping on the random response of beams. Mean square maximum deflection, mean square maximum strain, and spectral density function of maximum strain for simple supported and clamped beams are obtained. It is shown analytically that nonlinear damping contributes significantly to the broadening of the response peak and to the mean square deflection and strain.

  10. A randomized, placebo-controlled trial of levetiracetam in central pain in multiple sclerosis

    DEFF Research Database (Denmark)

    Falah, M; Madsen, C; Holbech, J V

    2012-01-01

    Levetiracetam is an anticonvulsant which is assumed to act by modulating neurotransmitter release via binding to the vesicle protein SV2A. This could have an impact on signalling in the pain pathway. The aim of this study was to test the analgesic effect of levetiracetam in central pain in multiple...... sclerosis. This was a randomized, double-blind, placebo-controlled, cross-over trial with levetiracetam 3000 mg/day versus placebo (6-week treatment periods). Patients with multiple sclerosis, symptoms and signs complying with central neuropathic pain and pain symptoms for more than 6 months, as well...... as pain intensity of more than 4 on a 0 to 10-point numeric rating scale were included in the study. The primary outcome measure was pain relief at the end of each treatment period as measured on a 6-point verbal scale. Eighty-nine patients were screened for participation and 30 patients entered the study...

  11. Integrative psychotherapeutic nursing home program to reduce multiple psychiatric symptoms of cognitively impaired patients and caregiver burden: randomized controlled trial

    NARCIS (Netherlands)

    Bakker, T.J.; Duivenvoorden, H.J.; Lee, J. van der; Olde Rikkert, M.G.M.; Beekman, A.T.; Ribbe, M.W.

    2011-01-01

    OBJECTIVE: To test the effectiveness of an integrative psychotherapeutic nursing home program (integrative reactivation and rehabilitation [IRR]) to reduce multiple neuropsychiatry symptoms (MNPS) of cognitively impaired patients and caregiver burden (CB). DESIGN: Randomized controlled trial.

  12. Making working memory work: the effects of extended practice on focus capacity and the processes of updating, forward access, and random access.

    Science.gov (United States)

    Price, John M; Colflesh, Gregory J H; Cerella, John; Verhaeghen, Paul

    2014-05-01

    We investigated the effects of 10h of practice on variations of the N-Back task to investigate the processes underlying possible expansion of the focus of attention within working memory. Using subtractive logic, we showed that random access (i.e., Sternberg-like search) yielded a modest effect (a 50% increase in speed) whereas the processes of forward access (i.e., retrieval in order, as in a standard N-Back task) and updating (i.e., changing the contents of working memory) were executed about 5 times faster after extended practice. We additionally found that extended practice increased working memory capacity as measured by the size of the focus of attention for the forward-access task, but not for variations where probing was in random order. This suggests that working memory capacity may depend on the type of search process engaged, and that certain working-memory-related cognitive processes are more amenable to practice than others. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Free choice access to multipoint wellness education and related services positively impacts employee wellness: a randomized and controlled trial.

    Science.gov (United States)

    Sforzo, Gary A; Kaye, Miranda P; Calleri, David; Ngai, Nancy

    2012-04-01

    Examine effects of voluntary participation in employer-sponsored, multipoint wellness education programming on employee wellness. A randomized and controlled design was used to organize 96 participants into an education + access group; an access-only group, and control group. Outcome measures were made at start and end of a 12-week intervention period. Education + access improved wellness knowledge, which, in turn, enhanced life satisfaction, employee morale, and energy, and nearly improved stress level. Those who received facility access without educational programming did not reap health benefits. Employees voluntarily used the fitness facility and healthy meal cards only 1.3 and 1.5 times per week, respectively. Participants made limited and likely inadequate use of wellness opportunities. As a result, physical health benefits (eg, blood pressure, fitness parameters) were not seen in the present study. However, multipoint wellness education resulted in psychosocial health benefits in 12 weeks.

  14. A randomized study of internet parent training accessed from community technology centers.

    Science.gov (United States)

    Irvine, A Blair; Gelatt, Vicky A; Hammond, Michael; Seeley, John R

    2015-05-01

    Behavioral parent training (BPT) has been shown to be efficacious to improve parenting skills for problematic interactions with adolescents displaying oppositional and antisocial behaviors. Some research suggests that support group curricula might be transferred to the Internet, and some studies suggest that other curriculum designs might also be effective. In this research, a BPT program for parents of at-risk adolescents was tested on the Internet in a randomized trial (N = 307) from computer labs at six community technology centers in or near large metropolitan areas. The instructional design was based on asynchronous scenario-based e-learning, rather than a traditional parent training model where presentation of course material builds content sequentially over multiple class sessions. Pretest to 30-day follow-up analyses indicated significant treatment effects on parent-reported discipline style (Parenting Scale, Adolescent version), child behavior (Eyberg Child Behavior Inventory), and on social cognitive theory constructs of intentions and self-efficacy. The effect sizes were small to medium. These findings suggest the potential to provide effective parent training programs on the Internet.

  15. Towards developing a compact model for magnetization switching in straintronics magnetic random access memory devices

    Science.gov (United States)

    Barangi, Mahmood; Erementchouk, Mikhail; Mazumder, Pinaki

    2016-08-01

    Strain-mediated magnetization switching in a magnetic tunneling junction (MTJ) by exploiting a combination of piezoelectricity and magnetostriction has been proposed as an energy efficient alternative to spin transfer torque (STT) and field induced magnetization switching methods in MTJ-based magnetic random access memories (MRAM). Theoretical studies have shown the inherent advantages of strain-assisted switching, and the dynamic response of the magnetization has been modeled using the Landau-Lifshitz-Gilbert (LLG) equation. However, an attempt to use LLG for simulating dynamics of individual elements in large-scale simulations of multi-megabyte straintronics MRAM leads to extremely time-consuming calculations. Hence, a compact analytical solution, predicting the flipping delay of the magnetization vector in the nanomagnet under stress, combined with a liberal approximation of the LLG dynamics in the straintronics MTJ, can lead to a simplified model of the device suited for fast large-scale simulations of multi-megabyte straintronics MRAMs. In this work, a tensor-based approach is developed to study the dynamic behavior of the stressed nanomagnet. First, using the developed method, the effect of stress on the switching behavior of the magnetization is investigated to realize the margins between the underdamped and overdamped regimes. The latter helps the designer realize the oscillatory behavior of the magnetization when settling along the minor axis, and the dependency of oscillations on the stress level and the damping factor. Next, a theoretical model to predict the flipping delay of the magnetization vector is developed and tested against LLG-based numerical simulations to confirm the accuracy of findings. Lastly, the obtained delay is incorporated into the approximate solutions of the LLG dynamics, in order to create a compact model to liberally and quickly simulate the magnetization dynamics of the MTJ under stress. Using the developed delay equation, the

  16. Towards developing a compact model for magnetization switching in straintronics magnetic random access memory devices

    Energy Technology Data Exchange (ETDEWEB)

    Barangi, Mahmood, E-mail: barangi@umich.edu; Erementchouk, Mikhail; Mazumder, Pinaki [Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109-2121 (United States)

    2016-08-21

    Strain-mediated magnetization switching in a magnetic tunneling junction (MTJ) by exploiting a combination of piezoelectricity and magnetostriction has been proposed as an energy efficient alternative to spin transfer torque (STT) and field induced magnetization switching methods in MTJ-based magnetic random access memories (MRAM). Theoretical studies have shown the inherent advantages of strain-assisted switching, and the dynamic response of the magnetization has been modeled using the Landau-Lifshitz-Gilbert (LLG) equation. However, an attempt to use LLG for simulating dynamics of individual elements in large-scale simulations of multi-megabyte straintronics MRAM leads to extremely time-consuming calculations. Hence, a compact analytical solution, predicting the flipping delay of the magnetization vector in the nanomagnet under stress, combined with a liberal approximation of the LLG dynamics in the straintronics MTJ, can lead to a simplified model of the device suited for fast large-scale simulations of multi-megabyte straintronics MRAMs. In this work, a tensor-based approach is developed to study the dynamic behavior of the stressed nanomagnet. First, using the developed method, the effect of stress on the switching behavior of the magnetization is investigated to realize the margins between the underdamped and overdamped regimes. The latter helps the designer realize the oscillatory behavior of the magnetization when settling along the minor axis, and the dependency of oscillations on the stress level and the damping factor. Next, a theoretical model to predict the flipping delay of the magnetization vector is developed and tested against LLG-based numerical simulations to confirm the accuracy of findings. Lastly, the obtained delay is incorporated into the approximate solutions of the LLG dynamics, in order to create a compact model to liberally and quickly simulate the magnetization dynamics of the MTJ under stress. Using the developed delay equation, the

  17. Physical and chemical mechanisms in oxide-based resistance random access memory.

    Science.gov (United States)

    Chang, Kuan-Chang; Chang, Ting-Chang; Tsai, Tsung-Ming; Zhang, Rui; Hung, Ya-Chi; Syu, Yong-En; Chang, Yao-Feng; Chen, Min-Chen; Chu, Tian-Jian; Chen, Hsin-Lu; Pan, Chih-Hung; Shih, Chih-Cheng; Zheng, Jin-Cheng; Sze, Simon M

    2015-01-01

    In this review, we provide an overview of our work in resistive switching mechanisms on oxide-based resistance random access memory (RRAM) devices. Based on the investigation of physical and chemical mechanisms, we focus on its materials, device structures, and treatment methods so as to provide an in-depth perspective of state-of-the-art oxide-based RRAM. The critical voltage and constant reaction energy properties were found, which can be used to prospectively modulate voltage and operation time to control RRAM device working performance and forecast material composition. The quantized switching phenomena in RRAM devices were demonstrated at ultra-cryogenic temperature (4K), which is attributed to the atomic-level reaction in metallic filament. In the aspect of chemical mechanisms, we use the Coulomb Faraday theorem to investigate the chemical reaction equations of RRAM for the first time. We can clearly observe that the first-order reaction series is the basis for chemical reaction during reset process in the study. Furthermore, the activation energy of chemical reactions can be extracted by changing temperature during the reset process, from which the oxygen ion reaction process can be found in the RRAM device. As for its materials, silicon oxide is compatible to semiconductor fabrication lines. It is especially promising for the silicon oxide-doped metal technology to be introduced into the industry. Based on that, double-ended graphene oxide-doped silicon oxide based via-structure RRAM with filament self-aligning formation, and self-current limiting operation ability is demonstrated. The outstanding device characteristics are attributed to the oxidation and reduction of graphene oxide flakes formed during the sputter process. Besides, we have also adopted a new concept of supercritical CO2 fluid treatment to efficiently reduce the operation current of RRAM devices for portable electronic applications.

  18. Improving access to cardiac rehabilitation using the internet: a randomized trial.

    Science.gov (United States)

    Lear, Scott A; Singer, Joel; Banner-Lukaris, Davina; Horvat, Dan; Park, Julie E; Bates, Joanna; Ignaszewski, Andrew

    2015-01-01

    Cardiac rehabilitation (CR) is essential for secondary prevention, yet only 10%-30% of eligible patients attend as geographical proximity is a major barrier. We evaluated a 'virtual' CR program (vCRP) delivered by the Internet to patients in small urban and rural areas. In our study, in-patients (n=78) with acute coronary syndrome or post-revascularization were randomized to usual care (UC) or vCRP. The vCRP was a four-month program that included heart rate monitoring; physiologic data capture; education sessions; ask-an-expert sessions; and chat sessions with a nurse, exercise specialist and dietitian. Participants were assessed at baseline and four months, and followed for another 12 months. The primary outcome was change in maximal time on the treadmill stress test (MTT) between groups adjusted for age, sex, diabetes status and Internet use for health information. The vCRP resulted in a greater increase in MTT by 45.7 seconds (95% CI: 1.0, 90.5) compared to usual care (p=0.045). Cholesterol levels and dietary quality improved in the vCRP compared to the UC group. Participants perceived the vCRP to be an accessible, convenient and effective way to received healthcare. Eleven (30%) and 6 (18%) participants in the UC and vCRP groups, respectively, had cardiovascular-related events (p=0.275). In conclusion, the vCRP was safe and effective and resulted in sustainable risk reduction without the requirement of face-to-face visits and directly monitored exercise.

  19. Analysis of self-heating of thermally assisted spin-transfer torque magnetic random access memory

    Directory of Open Access Journals (Sweden)

    Austin Deschenes

    2016-11-01

    Full Text Available Thermal assistance has been shown to significantly reduce the required operation power for spin torque transfer magnetic random access memory (STT-MRAM. Proposed heating methods include modified material stack compositions that result in increased self-heating or external heat sources. In this work we analyze the self-heating process of a standard perpendicular magnetic anisotropy STT-MRAM device through numerical simulations in order to understand the relative contributions of Joule, thermoelectric Peltier and Thomson, and tunneling junction heating. A 2D rotationally symmetric numerical model is used to solve the coupled electro-thermal equations including thermoelectric effects and heat absorbed or released at the tunneling junction. We compare self-heating for different common passivation materials, positive and negative electrical current polarity, and different device thermal anchoring and boundaries resistance configurations. The variations considered are found to result in significant differences in maximum temperatures reached. Average increases of 3 K, 10 K, and 100 K for different passivation materials, positive and negative polarity, and different thermal anchoring configurations, respectively, are observed. The highest temperatures, up to 424 K, are obtained for silicon dioxide as the passivation material, positive polarity, and low thermal anchoring with thermal boundary resistance configurations. Interestingly it is also found that due to the tunneling heat, Peltier effect, device geometry, and numerous interfacial layers around the magnetic tunnel junction (MTJ, most of the heat is dissipated on the lower potential side of the magnetic junction. This asymmetry in heating, which has also been observed experimentally, is important as thermally assisted switching requires heating of the free layer specifically and this will be significantly different for the two polarity operations, set and reset.

  20. Genetic variations of Lansium domesticum Corr. accessions from Java, Sumatra and Ceram based on Random Amplified Polymorphic DNA fingerprints

    Directory of Open Access Journals (Sweden)

    KUSUMADEWI SRI YULITA

    2011-07-01

    Full Text Available Yulita KS (2011 Genetic variations of Lansium domesticum Corr. accessions from Java, Bengkulu and Ceram based on Random Amplified Polymorphic DNA fingerprints. Biodiversitas 12: 125-130. Duku (Lansium domesticum Corr. is one of popular tropical fruits in SE Asia. The spesies has three varieties, known as duku, langsat and kokosan; and duku is the most popular one for being the sweetiest fruit. Indonesia has several local varieties of duku, such as duku Condet, duku Sumber and duku Palembang. This present study aimed to assess genetic diversity of 47 accessions of duku from Java, Sumatra, and Ceram based on RAPD fingerprints. Ten RAPD’s primers were initially screened and five were selected for the analysis. These five primers (OPA 7, 13, 18, OPB 7, and OPN 12 generated 53 scorable bands with an average of 10.6 polymorphic fragment per primer. Percentage of polymorphism ranged from 16.89% (OPA 7 and OPN 12 to 24.54% (OPB 7 with an average of 20.16% polymorphism. OPB 7 at 450 bp was exclusively possessed by accession 20 (Java, OPA 18 at 500 bp was by accession 6 (Java, 550 bp by 3 clones from Bengkulu. While OPN 12 at 300 bp and OPA 13 at 450 bp were shared among the accessions. Clustering analysis was performed based on RAPD profiles using the UPGMA method. The range of genetic similarity value among accessions was 0.02-0.65 suggesting high variation of gene pool existed among accessions.

  1. Asymmetric multiple information cryptosystem based on chaotic spiral phase mask and random spectrum decomposition

    Science.gov (United States)

    Rafiq Abuturab, Muhammad

    2018-01-01

    A new asymmetric multiple information cryptosystem based on chaotic spiral phase mask (CSPM) and random spectrum decomposition is put forwarded. In the proposed system, each channel of secret color image is first modulated with a CSPM and then gyrator transformed. The gyrator spectrum is randomly divided into two complex-valued masks. The same procedure is applied to multiple secret images to get their corresponding first and second complex-valued masks. Finally, first and second masks of each channel are independently added to produce first and second complex ciphertexts, respectively. The main feature of the proposed method is the different secret images encrypted by different CSPMs using different parameters as the sensitive decryption/private keys which are completely unknown to unauthorized users. Consequently, the proposed system would be resistant to potential attacks. Moreover, the CSPMs are easier to position in the decoding process owing to their own centering mark on axis focal ring. The retrieved secret images are free from cross-talk noise effects. The decryption process can be implemented by optical experiment. Numerical simulation results demonstrate the viability and security of the proposed method.

  2. Omega-3 Fatty Acids for Depression in Multiple Sclerosis: A Randomized Pilot Study.

    Directory of Open Access Journals (Sweden)

    Lynne Shinto

    Full Text Available Multiple sclerosis is the most common chronic disabling disease in the central nervous system in young to middle aged adults. Depression is common in multiple sclerosis (MS affecting between 50–60% of patients. Pilot studies in unipolar depression report an improvement in depression when omega-3 fatty acids are given with antidepressants. The objective of this study was to investigate whether omega-3 fatty acid supplementation, as an augmentation therapy, improves treatment-resistant major depressive disorder (MDD in people with MS. We performed a randomized, double-blind, placebo-controlled pilot study of omega-3 fatty acids at six grams per day over three months. The primary outcome was a 50% or greater improvement on the Montgomery-Asberg Depression Rating Scale (MADRS. Thirty-nine participants were randomized and thirty-one completed the 3-month intervention. Improvement on MADRS between groups was not significantly different at the 3-month end point with 47.4% in the omega-3 fatty acid group and 45.5% in the placebo group showing 50% or greater improvement (p = 0.30. Omega-3 fatty acids as an augmentation therapy for treatment-resistant depression in MS was not significantly different than placebo in this pilot trial. Omega-3 fatty acid supplementation at the dose given was well-tolerated over 3 months.ClinicalTrials.gov NCT00122954.

  3. Omega-3 Fatty Acids for Depression in Multiple Sclerosis: A Randomized Pilot Study.

    Science.gov (United States)

    Shinto, Lynne; Marracci, Gail; Mohr, David C; Bumgarner, Lauren; Murchison, Charles; Senders, Angela; Bourdette, Dennis

    2016-01-01

    Multiple sclerosis is the most common chronic disabling disease in the central nervous system in young to middle aged adults. Depression is common in multiple sclerosis (MS) affecting between 50–60% of patients. Pilot studies in unipolar depression report an improvement in depression when omega-3 fatty acids are given with antidepressants. The objective of this study was to investigate whether omega-3 fatty acid supplementation, as an augmentation therapy, improves treatment-resistant major depressive disorder (MDD) in people with MS. We performed a randomized, double-blind, placebo-controlled pilot study of omega-3 fatty acids at six grams per day over three months. The primary outcome was a 50% or greater improvement on the Montgomery-Asberg Depression Rating Scale (MADRS). Thirty-nine participants were randomized and thirty-one completed the 3-month intervention. Improvement on MADRS between groups was not significantly different at the 3-month end point with 47.4% in the omega-3 fatty acid group and 45.5% in the placebo group showing 50% or greater improvement (p = 0.30). Omega-3 fatty acids as an augmentation therapy for treatment-resistant depression in MS was not significantly different than placebo in this pilot trial. Omega-3 fatty acid supplementation at the dose given was well-tolerated over 3 months. ClinicalTrials.gov NCT00122954.

  4. Random exponential attractor for cocycle and application to non-autonomous stochastic lattice systems with multiplicative white noise

    Science.gov (United States)

    Zhou, Shengfan

    2017-08-01

    We first establish some sufficient conditions for constructing a random exponential attractor for a continuous cocycle on a separable Banach space and weighted spaces of infinite sequences. Then we apply our abstract result to study the existence of random exponential attractors for non-autonomous first order dissipative lattice dynamical systems with multiplicative white noise.

  5. Cortical atrophy patterns in multiple sclerosis are non-random and clinically relevant.

    Science.gov (United States)

    Steenwijk, Martijn D; Geurts, Jeroen J G; Daams, Marita; Tijms, Betty M; Wink, Alle Meije; Balk, Lisanne J; Tewarie, Prejaas K; Uitdehaag, Bernard M J; Barkhof, Frederik; Vrenken, Hugo; Pouwels, Petra J W

    2016-01-01

    %). Several cortical atrophy patterns relevant for multiple sclerosis were found. This suggests that cortical atrophy in multiple sclerosis occurs largely in a non-random manner and develops (at least partly) according to distinct anatomical patterns. In addition, these cortical atrophy patterns showed stronger associations with clinical (especially cognitive) dysfunction than global cortical atrophy. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. POROSIMETRY BY DOUBLE-RANDOM MULTIPLE TREE STRUCTURING IN VIRTUAL CONCRETE

    Directory of Open Access Journals (Sweden)

    Piet Stroeven

    2012-03-01

    Full Text Available Two different porosimetry methods are presented in two successive papers. Inspiration for the development came from the rapidly-exploring random tree (RRT approach used in robotics. The novel methods are applied to virtual cementitious materials produced by a modern concurrent algorithm-based discrete element modeling system, HADES. This would render possible realistically simulating all aspects of particulate matter that influence structure-sensitive features of the pore network structure in maturing concrete, namely size, shape and dispersion of aggregate and cement particles. Pore space is a complex tortuous entity. Practical methods conventionally applied for assessment of pore size distribution may fail or present biased information. Among them, mercury intrusion porosimetry and 2D quantitative image analysis are popular. The mathematical morphology operator “opening” can be applied to sections and even provide 3D information on pore size distribution, provided isotropy is guaranteed. Unfortunately, aggregate grain surfaces lead to pore anisotropy. The presented methods allow exploration of pore space in the virtual material, after which pore size distribution is derived from star volume measurements.  In addition to size of pores their continuity is of crucial importance for durability estimation. Double-random multiple tree structuring (DRaMuTS, presented herein, and random node structuring (RaNoS provide such information. The latter method will be introduced in a next issue of IA&S.

  7. Is customized vestibular rehabilitation effective in patients with multiple sclerosis? A randomized controlled trial.

    Science.gov (United States)

    Ozgen, Gulnur; Karapolat, Hale; Akkoc, Yesim; Yuceyar, Nur

    2016-08-01

    Balance disorders are among the most common problems encountered by patients diagnosed with multiple sclerosis (MS). The purpose of this randomized, controlled trial was to investigate the effects of customized vestibular rehabilitation (VR) on balance, functional capacity, quality of life, and depression in patients with MS. This study was designed as a prospective, randomized, controlled trial. The study was carried out in a single tertiary referral center. Forty consecutive patients referred with a diagnosis of MS were randomized into two groups: an exercise group (N.=20) and a control group (N.=20). The experimental group underwent customized VR and the wait-listed control group received the usual medical care. All of the patients were assessed with objective balance tests (Romberg Test, Tandem Romberg Test, Foam Romberg Test, Static Posturography, Six-Meter Walk Test, Five Times Sit-to-Stand Test, Berg Balance Scale, Timed Up and Go Test, Functional Gait Assessment, and Dynamic Gait Index), subjective balance parameters (Activities-Specific Balance Confidence Scale and Dizziness Handicap Inventory), and functional capacity (Six-Minute Walking Test), quality of life (Multiple Sclerosis Quality of Life-54), and depression (Beck Depression Inventory) scales. At the end of the trial, the exercise group exhibited significant changes in most of the evaluated parameters compared to the control group [except the Tandem Romberg with eyes closed and the Foam Romberg, standing with eyes open (P0.05). The intergroup comparisons of differences indicated significant recoveries in favor of the exercise group in all of the evaluated parameters (P<0.05). This study confirms the effects of customized VR programs on balance, quality of life, and functional capacity in patients with MS. Customized VR is an effective method for treating balance disorders in patients with MS.

  8. Dual task training in persons with Multiple Sclerosis: a feasability randomized controlled trial.

    Science.gov (United States)

    Sosnoff, Jacob J; Wajda, Douglas A; Sandroff, Brian M; Roeing, Kathleen L; Sung, JongHun; Motl, Robert W

    2017-10-01

    To determine the feasibility of dual task training in persons with Multiple Sclerosis. Randomized, single-blinded controlled trial. University research laboratory. A total of 234 individuals inquired about the investigation. After screening, 20 individuals with multiple sclerosis who self-reported problems with multitasking and were ambulatory volunteered for the investigation. 14 participants completed the post-assessment following the 12-week intervention. Participants were randomly assigned to either single task training program which focused on balance and walking function ( n=6) or dual task training program that incorporated cognitive tasks in balance and walking training ( n=8). Before and after the 12-week interventions participants underwent assessments of walking; dual task walking; balance (Berg Balance Scale and balance confidence) and cognition as indexed by the Brief International Cognitive Assessment for MS. There was an 8.5% recruitment rate, a 70% retention rate, and a 100% adherence rate. There was a trend for dual task gait speed to improve in the dual task training group following the intervention (Pre: task 1: 109.8±39, task 2: 104.2±34.1; Post: task 1:127.6±40.1, task 2: 122.8±37.4; P=0.14; η(2) = 0.24). There was also a trend for the dual task training group (28.1) to have greater performance than the control group (24.7) on visuospatial memory ( P=0.10; η(2)= 0.23). There were no changes in cognitive performance during walking trials. The study procedures were found to be feasible and improvements should be made in recruitment efforts going forward. Further examination of dual task training programs in individuals with multiple sclerosis is warranted.

  9. Massage therapy and exercise therapy in patients with multiple sclerosis: a randomized controlled pilot study.

    Science.gov (United States)

    Negahban, Hossein; Rezaie, Solmaz; Goharpey, Shahin

    2013-12-01

    The primary aim was to investigate the comparative effects of massage therapy and exercise therapy on patients with multiple sclerosis. The secondary aim was to investigate whether combination of both massage and exercise has an additive effect. Randomized controlled pilot trial with repeated measurements and blinded assessments. Local Multiple Sclerosis Society. A total of 48 patients with multiple sclerosis were randomly assigned to four equal subgroups labelled as massage therapy, exercise therapy, combined massage-exercise therapy and control group. The treatment group received 15 sessions of supervised intervention for five weeks. The massage therapy group received a standard Swedish massage. The exercise therapy group was given a combined set of strength, stretch, endurance and balance exercises. Patients in the massage-exercise therapy received a combined set of massage and exercise treatments. Patients in the control group were asked to continue their standard medical care. Pain, fatigue, spasticity, balance, gait and quality of life were assessed before and after intervention. Massage therapy resulted in significantly larger improvement in pain reduction (mean change 2.75 points, P = 0.001), dynamic balance (mean change, 3.69 seconds, P = 0.009) and walking speed (mean change, 7.84 seconds, P = 0.007) than exercise therapy. Patients involved in the combined massage-exercise therapy showed significantly larger improvement in pain reduction than those in the exercise therapy (mean change, 1.67 points, P = 0.001). Massage therapy could be more effective than exercise therapy. Moreover, the combination of massage and exercise therapy may be a little more effective than exercise therapy alone.

  10. Data Management for Flexible Access - Implementation and Lessons Learned from work with Multiple User Communities

    Science.gov (United States)

    Benedict, K. K.; Scott, S.; Hudspeth, W. B.

    2012-12-01

    There is no shortage of community-specific and generic data discovery and download platforms and protocols (e.g. CUAHSI HIS, DataONE, GeoNetwork Open Source, GeoPortal, OGC CSW, OAI PMH), documentation standards (e.g. FGDC, ISO 19115, EML, Dublin Core), data access and visualization standards and models (e.g. OGC WxS, OpenDAP), and general-purpose web service models (i.e. REST & SOAP) upon which Geo-informatics cyberinfrastructure (CI) may be built. When attempting to develop a robust platform that may service a wide variety of users and use cases the challenge is one of identifying which existing platform (if any) may support those current needs while also allowing for future expansion for additional capabilities. In the case of the implementation of a data storage, discovery and delivery platform to support the multiple projects at the Earth Data Analysis Center at UNM, no single platform or protocol met the joint requirements of two initial applications (the New Mexico Resource Geographic Information System [http://rgis.unm.edu] and the New Mexico EPSCoR Data Portal [http://nmepscor.org/dataportal]) and furthermore none met anticipated additional requirements as new applications of the platform emerged. As a result of this assessment three years ago EDAC embarked on the development of the Geographic Storage, Transformation, and Retrieval Engine (GSToRE) platform as a general purpose platform upon which n-tiered geospatially enabled data intensive applications could be built. When initially released in 2010 the focus was on the publication of dynamically generated Open Geospatial Consortium services based upon a PostgreSQL/PostGIS backend database. The identification of additional service interface requirements (implementation of the DataONE API and CUAHSI WaterML services), use cases provided by the NM EPSCoR education working group, and expanded metadata publication needs have led to a significant update to the underlying data management tier for GSToRE - the

  11. A spectral phase encoded time spreading optical code division multiple access testbed

    Science.gov (United States)

    Cong, Wei

    Spectral phase-encode time-spreading (SPECTS) is a promising technique for optical code-division multiple-access (O-CDMA) networks. In SPECTS O-CDMA, users are multiplexed and distinguished with unique phase codes impressed on the spectrum of ultra-short optical signal pulses. The encoding and decoding processes are implemented with grating/lens zero-dispersion pulse-shapers using spatial light phase modulators (SLPMs) in the Fourier plane. The SLPMs add the encoding or decoding O-CDMA phase codes on the spectrum which is spatially spread and then recombined by the grating(s) and lens(es). In this dissertation, we demonstrate a SPECTS O-CDMA network testbed with large throughputs and high performances. Two types of fiber-pigtailed bulk-optic pulseshapers, 1-D transparent-mode and 2-D reflective-mode, are constructed to be used as SPECTS O-CDMA encoders and decoders in the testbed. In order to support a large number of users, the testbed includes up to eight SPECTS O-CDMA encoding channels and one decoding channel. With the combination of time-slotting and polarization-multiplexing operations, the maximum throughput achieved on the testbed is 32 users (8 O-CDMA channel x 2 time slots x 2 polarizations) at 10 Gb/s/user. Two nonlinear detecting techniques (thresholding and gating) for coherent SPECTS O-CDMA are discussed in the dissertation. A nonlinear thresholder and a nonlinear optical loop mirror (NOLM) time gate are built in the testbed; each uses a 500-m highly nonlinear fiber(HNLF). An "O-CDMA receiver" including the NOLM and the thresholder followed by an optical-electrical (O-E) converter can distinguish the intended user by demultiplexing the time-slotted signal and then suppressing the multi-user interference (MUI). In the bit-error-rate (BER) statistics experiments, the "O-CDMA receiver" can detect the intended user's signal with error-free or low BER performance in various testbed structures. Network-layer application experiments including video

  12. Design Optimization of Back-Gated Thin-Body Silicon-on-Insulator Capacitorless Dynamic Random Access Memory Cell

    Science.gov (United States)

    Cho, Min Hee; Shin, Changhwan; King Liu, Tsu-Jae

    2012-02-01

    Highly scaled (22 nm-node) capacitorless single-transistor dynamic random access memory (DRAM) cell design is investigated via technology computer-aided design (TCAD) simulations. It is found that the gate-sidewall spacer width and operating voltages can be adjusted to reduce band-to-band tunneling (BTBT) and thereby increase data retention time for bipolar junction transistor (BJT)-based operation. Read current variations due to random dopant fluctuations (RDF) are investigated via three-dimensional Kinetic Monte Carlo (KMC) simulations. It is found that BJT-based operation is more robust to RDF effects than metal-oxide-semiconductor field-effect transistor (MOSFET)-based operation.

  13. Multiple micronutrient supplementation for improving cognitive performance in children: systematic review of randomized controlled trials.

    Science.gov (United States)

    Eilander, Ans; Gera, Tarun; Sachdev, Harshpal S; Transler, Catherine; van der Knaap, Henk Cm; Kok, Frans J; Osendarp, Saskia Jm

    2010-01-01

    Although multiple micronutrient interventions have been shown to benefit children's intellectual development, a thorough evaluation of the totality of evidence is currently lacking to direct public health policy. This study aimed to systematically review the present literature and to quantify the effect of multiple micronutrients on cognitive performance in schoolchildren. The Institute for Scientific Information Web of Knowledge and local medical databases were searched for trials published from 1970 to 2008. Randomized controlled trials that investigated the effect of > or =3 micronutrients compared with placebo on cognition in healthy children aged 0-18 y were included following protocol. Data were extracted by 2 independent researchers. The cognitive tests used in the trials were grouped into several cognitive domains (eg, fluid and crystallized intelligence), and pooled effect size estimates were calculated per domain. Heterogeneity was explored through sensitivity and meta-regression techniques. Three trials were retrieved in children aged intelligence and -0.03 SD (95% CI: -0.21, 0.15; P = 0.74) for crystallized intelligence, both of which were based on 12 trials. Four trials yielded an overall effect of 0.30 SD (95% CI: 0.01, 0.58; P = 0.044) for academic performance. For other cognitive domains, no significant effects were found. Multiple micronutrient supplementation may be associated with a marginal increase in fluid intelligence and academic performance in healthy schoolchildren but not with crystallized intelligence. More research is required, however, before public health recommendations can be given.

  14. Comparison of a Ring On-Chip Network and a Code-Division Multiple-Access On-Chip Network

    OpenAIRE

    Xin Wang; Jari Nurmi

    2007-01-01

    Two network-on-chip (NoC) designs are examined and compared in this paper. One design applies a bidirectional ring connection scheme, while the other design applies a code-division multiple-access (CDMA) connection scheme. Both of the designs apply globally asynchronous locally synchronous (GALS) scheme in order to deal with the issue of transferring data in a multiple-clock-domain environment of an on-chip system. The two NoC designs are compared with each other by their network structures, ...

  15. Multiple-image authentication with a cascaded multilevel architecture based on amplitude field random sampling and phase information multiplexing.

    Science.gov (United States)

    Fan, Desheng; Meng, Xiangfeng; Wang, Yurong; Yang, Xiulun; Pan, Xuemei; Peng, Xiang; He, Wenqi; Dong, Guoyan; Chen, Hongyi

    2015-04-10

    A multiple-image authentication method with a cascaded multilevel architecture in the Fresnel domain is proposed, in which a synthetic encoded complex amplitude is first fabricated, and its real amplitude component is generated by iterative amplitude encoding, random sampling, and space multiplexing for the low-level certification images, while the phase component of the synthetic encoded complex amplitude is constructed by iterative phase information encoding and multiplexing for the high-level certification images. Then the synthetic encoded complex amplitude is iteratively encoded into two phase-type ciphertexts located in two different transform planes. During high-level authentication, when the two phase-type ciphertexts and the high-level decryption key are presented to the system and then the Fresnel transform is carried out, a meaningful image with good quality and a high correlation coefficient with the original certification image can be recovered in the output plane. Similar to the procedure of high-level authentication, in the case of low-level authentication with the aid of a low-level decryption key, no significant or meaningful information is retrieved, but it can result in a remarkable peak output in the nonlinear correlation coefficient of the output image and the corresponding original certification image. Therefore, the method realizes different levels of accessibility to the original certification image for different authority levels with the same cascaded multilevel architecture.

  16. A satellite mobile communication system based on Band-Limited Quasi-Synchronous Code Division Multiple Access (BLQS-CDMA)

    Science.gov (United States)

    Degaudenzi, R.; Elia, C.; Viola, R.

    1990-01-01

    Discussed here is a new approach to code division multiple access applied to a mobile system for voice (and data) services based on Band Limited Quasi Synchronous Code Division Multiple Access (BLQS-CDMA). The system requires users to be chip synchronized to reduce the contribution of self-interference and to make use of voice activation in order to increase the satellite power efficiency. In order to achieve spectral efficiency, Nyquist chip pulse shaping is used with no detection performance impairment. The synchronization problems are solved in the forward link by distributing a master code, whereas carrier forced activation and closed loop control techniques have been adopted in the return link. System performance sensitivity to nonlinear amplification and timing/frequency synchronization errors are analyzed.

  17. Studies on Structural and Resistive Switching Properties of Al/ZnO/Al Structured Resistive Random Access Memory

    Science.gov (United States)

    Li, Hongxia; Chen, Yiming; Wu, Xin; Xi, Junhua; Huang, Yanwei; Ji, Zhenguo

    Recently, resistive random access memory has been continuously investigated in order to replace the flash memory. In this paper, Al/ZnO/Al structured device was fabricated by magnetron sputtering and vacuum thermal evaporation. Systematic study has been conducted to explore the structural, morphological, and the resistive switching properties of ZnO films with Al metal as both bottom and top electrodes. The resistive switching mechanism of Al/ZnO/Al device was analyzed based on the above study.

  18. A Novel Architecture for Adaptive Traffic Control in Network on Chip using Code Division Multiple Access Technique

    OpenAIRE

    Fatemeh. Dehghani; Shahram. Darooei

    2016-01-01

    Network on chip has emerged as a long-term and effective method in Multiprocessor System-on-Chip communications in order to overcome the bottleneck in bus based communication architectures. Efficiency and performance of network on chip is so dependent on the architecture and structure of the network. In this paper a new structure and architecture for adaptive traffic control in network on chip using Code Division Multiple Access technique is presented. To solve the problem of synchronous acce...

  19. Resistive Random Access Memory from Materials Development fnd Engineering to Novel Encryption and Neuromorphic Applications

    Science.gov (United States)

    Beckmann, Karsten

    Resistive random access memory (ReRAM or RRAM) is a novel form of non-volatile memory that is expected to play a major role in future computing and memory solutions. It has been shown that the resistance state of ReRAM devices can be precisely tuned by modulating switching voltages, by limiting peak current, and by adjusting the switching pulse properties. This enables the realization of novel applications such as memristive neuromorphic computing and neural network computing. I have developed two processes based on 100 and 300mm wafer platforms to demonstrate functional HfO2 based ReRAM devices. The first process is designed for a rapid materials engineering and device characterization, while the second is an advanced hybrid ReRAM/CMOS combination based on the IBM 65nm 10LPe process technology. The 100mm wafer efforts were used to show impacts of etch processes on ReRAM switching performance and the need for a rigorous structural evaluation of ReRAM devices before starting materials development. After an etch development, a bottom electrode comparison between the inert materials Pt, Ru and W was performed where Ru showed superior results with respect to yield and resilience against environmental impacts such as humidity over a 2-month period. A comparison of amorphous and crystalline devices showed no statistical difference in the performance with respect to random telegraph noise. This demonstrates, that the forming process fundamentally alters the crystallographic structure within and around the filament. The 300mm wafer development efforts were aimed towards implementing ReRAM in the FEOL, combined with CMOS, to yield a seamless process flow of 1 transistor 1 ReRAM structures (1T1R). This technology was customized with custom-developed tungsten metal 1 (M1) and dual tungsten/copper via 1 (V1) structures, within which the ReRAM stack is embedded. The ReRAM itself consists of an inert W bottom electrode, HfO2 based active switching layer, a Ti oxygen scavenger

  20. A MAC protocol with high scalability for motion capture based on frequency division multiple and time division multiple access.

    Science.gov (United States)

    Wang Yongfeng; Jie Li; Shengyun Liang; Yingnan Ma; Xing Gao; Shuncheng Fan; Yunkun Ning; Cuiju Xiong; Lei Wang; Guoru Zhao

    2017-07-01

    A good performance of motion capture, which belongs to body sensor network, depends on a reasonable design of MAC protocol. The purpose of this study is to design a reliable and highly extensible protocol for applying in motion capture. The proposed MAC protocol can easily be actualized by the timer in the chip. With this MAC protocol, the network would be built quickly. One or more nodes could be added easily in the net or deleted randomly from the net. In order to verify the superiority of this protocol, a series of experiments were designed. The results showed that the mean of simulation receive frames for node1-node7 from each stage were very close to the original frames. In addition, the final Pocket Loss Rates for node1-node7 were 0.081%, 0.175%, 0.143%, 0.249%, 0.248%, 0.044% and 1.897%, which could be in the error-allowed range. Thus, this protocol is stable and reliable, which can be widely used to capture human movement signal.

  1. Generalized linear longitudinal mixed models with linear covariance structure and multiplicative random effects

    DEFF Research Database (Denmark)

    Holst, René; Jørgensen, Bent

    2015-01-01

    The paper proposes a versatile class of multiplicative generalized linear longitudinal mixed models (GLLMM) with additive dispersion components, based on explicit modelling of the covariance structure. The class incorporates a longitudinal structure into the random effects models and retains...... a marginal as well as a conditional interpretation. The estimation procedure is based on a computationally efficient quasi-score method for the regression parameters combined with a REML-like bias-corrected Pearson estimating function for the dispersion and correlation parameters. This avoids...... the multidimensional integral of the conventional GLMM likelihood and allows an extension of the robust empirical sandwich estimator for use with both association and regression parameters. The method is applied to a set of otholit data, used for age determination of fish....

  2. Studies with staggered starts: multiple baseline designs and group-randomized trials.

    Science.gov (United States)

    Rhoda, Dale A; Murray, David M; Andridge, Rebecca R; Pennell, Michael L; Hade, Erinn M

    2011-11-01

    Multiple baseline designs (MBDs) have been suggested as alternatives to group-randomized trials (GRT). We reviewed structural features of MBDs and considered their potential effectiveness in public health research. We also reviewed the effect of staggered starts on statistical power. We reviewed the MBD literature to identify key structural features, recent suggestions that MBDs be adopted in public health research, and the literature on power in GRTs with staggered starts. We also computed power for MBDs and GRTs. The features that have contributed to the success of small MBDs in some fields are not likely to translate well to public health research. MBDs can be more powerful than GRTs under some conditions, but those conditions involve assumptions that require careful evaluation in practice. MBDs will often serve better as a complement of rather than as an alternative to GRTs. GRTs may employ staggered starts for logistical or ethical reasons, but this will always increase their duration and will often increase their cost.

  3. Coupled effect of stimulated Raman scattering and random lasing of dyes in multiple scattering medium

    Science.gov (United States)

    Yashchuk, Vasil P.

    2015-07-01

    Random lasing (RL) and stimulated Raman scattering (SRS) of dye in multiple scattering media (MSM) appears simultaneously and each couple with other. This coupling has considerable influence on the SRS regularities of dye in MSM. The main feature of this impact is that RL radiation promotes the Raman lines revealing in the RL spectrum range as part of total radiation. SRS initiation occurs owing to the CARS-like mechanism provided by the two component pump: incident monochromatic radiation (laser pump) and RL radiation arising inside the MSM. It leads to important consequences: the RL spectrum must overlap with the spectral region of the possible Stokes lines of the dye; only those Stokes lines appear which are in a range of the RL spectrum; all conditions which promote RL assist SRS also. It is shown MSM promotes the best conditions for SRS and RL coupling due to optimal matching of RL localization regions and pump radiation.

  4. Power- and Low-Resistance-State-Dependent, Bipolar Reset-Switching Transitions in SiN-Based Resistive Random-Access Memory

    Science.gov (United States)

    Kim, Sungjun; Park, Byung-Gook

    2016-08-01

    A study on the bipolar-resistive switching of an Ni/SiN/Si-based resistive random-access memory (RRAM) device shows that the influences of the reset power and the resistance value of the low-resistance state (LRS) on the reset-switching transitions are strong. For a low LRS with a large conducting path, the sharp reset switching, which requires a high reset power (>7 mW), was observed, whereas for a high LRS with small multiple-conducting paths, the step-by-step reset switching with a low reset power (device, which are not too strong and not too weak, offer considerable potential for the realization of low-power and high-density crossbar-array applications.

  5. Multimodal exercise training in multiple sclerosis: A randomized controlled trial in persons with substantial mobility disability.

    Science.gov (United States)

    Sandroff, Brian M; Bollaert, Rachel E; Pilutti, Lara A; Peterson, Melissa L; Baynard, Tracy; Fernhall, Bo; McAuley, Edward; Motl, Robert W

    2017-10-01

    Mobility disability is a common, debilitating feature of multiple sclerosis (MS). Exercise training has been identified as an approach to improve MS-related mobility disability. However, exercise randomized controlled trials (RCTs) on mobility in MS have generally not selectively targeted those with the onset of irreversible mobility disability. The current multi-site RCT compared the efficacy of 6-months of supervised, multimodal exercise training with an active control condition for improving mobility, gait, physical fitness, and cognitive outcomes in persons with substantial MS-related mobility disability. 83 participants with substantial MS-related mobility disability underwent initial mobility, gait, fitness, and cognitive processing speed assessments and were randomly assigned to 6-months of supervised multimodal (progressive aerobic, resistance, and balance) exercise training (intervention condition) or stretching-and-toning activities (control condition). Participants completed the same outcome assessments halfway through and immediately following the 6-month study period. There were statistically significant improvements in six-minute walk performance (F(2158)=3.12, p=0.05, ηp2=0.04), peak power output (F(2150)=8.16, pmobility disability. This is critical for informing the development of multi-site exercise rehabilitation programs in larger samples of persons with MS-related mobility disability. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Hydrotherapy for the Treatment of Pain in People with Multiple Sclerosis: A Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Adelaida María Castro-Sánchez

    2012-01-01

    Full Text Available Background. Multiple sclerosis (MS is a chronic demyelinating neurological disease. Several studies have reported that complementary and alternative therapies can have positive effects against pain in these patients. Objective. The objective was to investigate the effectiveness of an Ai-Chi aquatic exercise program against pain and other symptoms in MS patients. Methods. In this randomized controlled trial, 73 MS patients were randomly assigned to an experimental or control group for a 20-week treatment program. The experimental group underwent 40 sessions of Ai-Chi exercise in swimming pool and the control group 40 sessions of abdominal breathing and contraction-relaxation exercises in therapy room. Outcome variables were pain, disability, spasm, depression, fatigue, and autonomy, which were assessed before the intervention and immediately and at 4 and 10 weeks after the last treatment session. Results. The experimental group showed a significant (P<0.028 and clinically relevant decrease in pain intensity versus baseline, with an immediate posttreatment reduction in median visual analogue scale scores of 50% that was maintained for up to 10 weeks. Significant improvements were also observed in spasm, fatigue, disability, and autonomy. Conclusion. According to these findings, an Ai-Chi aquatic exercise program improves pain, spasms, disability, fatigue, depression, and autonomy in MS patients.

  7. Automatic detection of gadolinium-enhancing multiple sclerosis lesions in brain MRI using conditional random fields.

    Science.gov (United States)

    Karimaghaloo, Zahra; Shah, Mohak; Francis, Simon J; Arnold, Douglas L; Collins, D Louis; Arbel, Tal

    2012-06-01

    Gadolinium-enhancing lesions in brain magnetic resonance imaging of multiple sclerosis (MS) patients are of great interest since they are markers of disease activity. Identification of gadolinium-enhancing lesions is particularly challenging because the vast majority of enhancing voxels are associated with normal structures, particularly blood vessels. Furthermore, these lesions are typically small and in close proximity to vessels. In this paper, we present an automatic, probabilistic framework for segmentation of gadolinium-enhancing lesions in MS using conditional random fields. Our approach, through the integration of different components, encodes different information such as correspondence between the intensities and tissue labels, patterns in the labels, or patterns in the intensities. The proposed algorithm is evaluated on 80 multimodal clinical datasets acquired from relapsing-remitting MS patients in the context of multicenter clinical trials. The experimental results exhibit a sensitivity of 98% with a low false positive lesion count. The performance of the proposed algorithm is also compared to a logistic regression classifier, a support vector machine and a Markov random field approach. The results demonstrate superior performance of the proposed algorithm at successfully detecting all of the gadolinium-enhancing lesions while maintaining a low false positive lesion count.

  8. Direct Simulation of Multiple Scattering by Discrete Random Media Illuminated by Gaussian Beams

    Science.gov (United States)

    Mackowski, Daniel W.; Mishchenko, Michael I.

    2011-01-01

    The conventional orientation-averaging procedure developed in the framework of the superposition T-matrix approach is generalized to include the case of illumination by a Gaussian beam (GB). The resulting computer code is parallelized and used to perform extensive numerically exact calculations of electromagnetic scattering by volumes of discrete random medium consisting of monodisperse spherical particles. The size parameters of the scattering volumes are 40, 50, and 60, while their packing density is fixed at 5%. We demonstrate that all scattering patterns observed in the far-field zone of a random multisphere target and their evolution with decreasing width of the incident GB can be interpreted in terms of idealized theoretical concepts such as forward-scattering interference, coherent backscattering (CB), and diffuse multiple scattering. It is shown that the increasing violation of electromagnetic reciprocity with decreasing GB width suppresses and eventually eradicates all observable manifestations of CB. This result supplements the previous demonstration of the effects of broken reciprocity in the case of magneto-optically active particles subjected to an external magnetic field.

  9. Community Health Worker Support for Disadvantaged Patients With Multiple Chronic Diseases: A Randomized Clinical Trial.

    Science.gov (United States)

    Kangovi, Shreya; Mitra, Nandita; Grande, David; Huo, Hairong; Smith, Robyn A; Long, Judith A

    2017-10-01

    To determine whether a community health worker (CHW) intervention improved outcomes in a low-income population with multiple chronic conditions. We conducted a single-blind, randomized clinical trial in Philadelphia, Pennsylvania (2013-2014). Participants (n = 302) were high-poverty neighborhood residents, uninsured or publicly insured, and diagnosed with 2 or more chronic diseases (diabetes, obesity, tobacco dependence, hypertension). All patients set a disease-management goal. Patients randomly assigned to CHWs also received 6 months of support tailored to their goals and preferences. Support from CHWs (vs goal-setting alone) led to improvements in several chronic diseases (changes in glycosylated hemoglobin: -0.4 vs 0.0; body mass index: -0.3 vs -0.1; cigarettes per day: -5.5 vs -1.3; systolic blood pressure: -1.8 vs -11.2; overall P = .08), self-rated mental health (12-item Short Form survey; 2.3 vs -0.2; P = .008), and quality of care (Consumer Assessment of Healthcare Providers and Systems; 62.9% vs 38%; P < .001), while reducing hospitalization at 1 year by 28% (P = .11). There were no differences in patient activation or self-rated physical health. A standardized CHW intervention improved chronic disease control, mental health, quality of care, and hospitalizations and could be a useful population health management tool for health care systems. clinicaltrials.gov identifier: NCT01900470.

  10. Modeling longitudinal data with nonparametric multiplicative random effects jointly with survival data.

    Science.gov (United States)

    Ding, Jimin; Wang, Jane-Ling

    2008-06-01

    In clinical studies, longitudinal biomarkers are often used to monitor disease progression and failure time. Joint modeling of longitudinal and survival data has certain advantages and has emerged as an effective way to mutually enhance information. Typically, a parametric longitudinal model is assumed to facilitate the likelihood approach. However, the choice of a proper parametric model turns out to be more elusive than models for standard longitudinal studies in which no survival endpoint occurs. In this article, we propose a nonparametric multiplicative random effects model for the longitudinal process, which has many applications and leads to a flexible yet parsimonious nonparametric random effects model. A proportional hazards model is then used to link the biomarkers and event time. We use B-splines to represent the nonparametric longitudinal process, and select the number of knots and degrees based on a version of the Akaike information criterion (AIC). Unknown model parameters are estimated through maximizing the observed joint likelihood, which is iteratively maximized by the Monte Carlo Expectation Maximization (MCEM) algorithm. Due to the simplicity of the model structure, the proposed approach has good numerical stability and compares well with the competing parametric longitudinal approaches. The new approach is illustrated with primary biliary cirrhosis (PBC) data, aiming to capture nonlinear patterns of serum bilirubin time courses and their relationship with survival time of PBC patients.

  11. Integrated Optical Content Addressable Memories (CAM and Optical Random Access Memories (RAM for Ultra-Fast Address Look-Up Operations

    Directory of Open Access Journals (Sweden)

    Christos Vagionas

    2017-07-01

    Full Text Available Electronic Content Addressable Memories (CAM implement Address Look-Up (AL table functionalities of network routers; however, they typically operate in the MHz regime, turning AL into a critical network bottleneck. In this communication, we demonstrate the first steps towards developing optical CAM alternatives to enable a re-engineering of AL memories. Firstly, we report on the photonic integration of Semiconductor Optical Amplifier-Mach Zehnder Interferometer (SOA-MZI-based optical Flip-Flop and Random Access Memories on a monolithic InP platform, capable of storing the binary prefix-address data-bits and the outgoing port information for next hop routing, respectively. Subsequently the first optical Binary CAM cell (B-CAM is experimentally demonstrated, comprising an InP Flip-Flop and a SOA-MZI Exclusive OR (XOR gate for fast search operations through an XOR-based bit comparison, yielding an error-free 10 Gb/s operation. This is later extended via physical layer simulations in an optical Ternary-CAM (T-CAM cell and a 4-bit Matchline (ML configuration, supporting a third state of the “logical X” value towards wildcard bits of network subnet masks. The proposed functional CAM and Random Access Memories (RAM sub-circuits may facilitate light-based Address Look-Up tables supporting search operations at 10 Gb/s and beyond, paving the way towards minimizing the disparity with the frantic optical transmission linerates, and fast re-configurability through multiple simultaneous Wavelength Division Multiplexed (WDM memory access requests.

  12. Effects of different exercise modalities on ataxia in multiple sclerosis patients: a randomized controlled study.

    Science.gov (United States)

    Salcı, Yeliz; Fil, Ayla; Armutlu, Kadriye; Yildiz, F Gökçem; Kurne, Aslı; Aksoy, Songül; Nurlu, Gülay; Karabudak, Rana

    2017-12-01

    To investigate the effects of different exercise protocols on ataxia in patients with multiple sclerosis (MS). A total of 42 MS patients, 17 male and 25 female (Expanded Disability Status Scale (EDSS): 3-5), were enrolled in this randomized controlled study. The patients were divided into three groups: a balance training (BT) group, a lumbar stabilization (LS) group and a task-oriented training (TT) group. All groups received balance training; additionally, the LS group received lumbar stabilization exercises, and the TT group received task-oriented training. The Berg Balance Scale (BBS), International Cooperative Ataxia Rating Scale (ICARS), Functional Reach Test (FRT), 2-Minute Walk Test (2MWT), Sensory Organization Test (SOT), and measurement of Somatosensory Evoked Potentials (SSEPs) were performed before and at the end of the 18 training sessions. The BBS, ICARS, FRT, 2MWT, and composite balance score of the SOT were improved in all groups. The ICARS kinetic function sub-score and the left limb cortical onset amplitudes of SSEPs were increased significantly in both the TT and the LS groups. The ICARS total score, composite balance score, and 2MWT were different between groups (p  0.005). The 2MWT results were better for the LS group than the BT group, while the BT and the TT groups improved similarly. Balance training alone is not sufficient for rehabilitation of ataxic MS patients. A combination of lumbar stabilization exercises or task-oriented training increases the success of balance rehabilitation. Implications for rehabilitation Multiple sclerosis is a chronic inflammatory and autoimmune disease of central nervous system and ataxia is one of the most challenging symptoms of this disease. Different exercise modalities are commonly employed to control ataxic symptoms in MS patients. Lumbar stabilization exercises or task-oriented training should be considered as complementary approach to improve balance and coordination in ataxic multiple sclerosis

  13. The effectiveness of transdermal opioid in the management multiple rib fractures: randomized clinical trial.

    Science.gov (United States)

    Solak, Okan; Oz, Gürhan; Kokulu, Serdar; Solak, Ozlem; Doğan, Gökçen; Esme, Hıdır; Ocalan, Kubilay; Baki, Elif Doğan

    2013-09-01

    The most commonly observed pathology in chest traumas is rib fracture, and the most important clinical symptom is severe pain. To investigate the effectiveness of intramuscular opioid (IMO), intravenous patient-controlled analgesia (IVPCA) and the Fentanyl transdermal therapeutic system (TTS) in the management of rib fracture pain. Prospective randomized clinical trial. In our prospective and randomised study, we included 45 patients with a diagnosis of multiple rib fractures. There were three groups and intercostal nerve blockage (ICB) in the first day and oral paracetamol for five days was administered to each group as standard. In Group IMO (n=15), 4×40 mg pethidine HCl was administered to the patients, while in Group IVPCA (n=15) this was 5 μg/mL continuous intravenous fentanyl and was 50 μg fentanyl TTS in Group TTS (n=15). The demographics, injury data and vital signs of the patients were recorded. Pain was scored using Visual Analogue Scale (VAS). The pain during lying down (VASl) and mobilisation (VASm) was detected. There were no differences between the three groups regarding age, sex, the trauma pattern, the number and distribution of costal fracture localisations, the presence of additional pathology, complications, thoracal catheter and the duration of thoracal catheter. No significant difference between the groups regarding systolic and diastolic arterial tension, number of breaths and beats in a minute was observed (p>0.05). We observed an improvement in the mean VAS score after treatment in all three groups. The mean VASl score significantly decreased after treatment in each group (p0.05). In the analgesia of patients with multiple rib fractures, TTS administration with ICB showed similar effectiveness with IVPCA administration with ICB. In the management of pain due to multiple rib fractures, TTS administration is a safe, non-invasive and effective procedure.

  14. BATHYTHERMOGRAPH (XBT) from multiple German platforms: 19730101 to 19831231 (NODC Accession 8400184)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Ocean Station Data and Bathythermograph (XBT) data were collected from Helgoland Biological Stations using multiple German ships (ANTON DOHRN, GAUSS, FRIEDRICH...

  15. Multiple Perspectives on the Accessibility of E-Learning in Canadian Colleges and Universities

    Science.gov (United States)

    Asuncion, Jennison V.; Fichten, Catherine S.; Ferraro, Vittoria; Chwojka, Caroline; Barile, Maria; Nguyen, Mai Nhu; Wolforth, Joan

    2010-01-01

    An exploratory study identified and compared the views of 77 campus disability service providers, 38 professors, and 45 e-learning professionals from Canadian colleges and universities regarding their experiences with e-learning and its accessibility to students with disabilities. Findings indicate that all groups saw benefit in having someone who…

  16. Theoretical analysis and simulation of a code division multiple access system (cdma for secure signal transmission in wideband channels

    Directory of Open Access Journals (Sweden)

    Stevan M. Berber

    2014-06-01

    Code Division Multiple Access (CDMA technique which allows communications of multiple users in the same communication system. This is achieved in such a way that each user is assigned a unique code sequence, which is used at the receiver side to discover the information dedicated to that user. These systems belong to the group of communication systems for direct sequence spread spectrum systems. Traditionally, CDMA systems use binary orthogonal spreading codes. In this paper, a mathematical model and simulation of a CDMA system based on the application of non-binary, precisely speaking, chaotic spreading sequences. In their nature, these sequences belong to random sequences with infinite periodicity, and due to that they are appropriate for applications in the systems that provide enhanced security against interception and secrecy in signal transmission. Numerous papers are dedicated to the development of CDMA systems in flat fading channels. This paper presents the results of these systems analysis for the case when frequency selective fading is present in the channel. In addition, the paper investigates a possibility of using interleaving techniques to mitigate fading in a wideband channel with the frequency selective fading. Basic structure of a CDMA communication system and its operation In this paper, a CDMA system block schematic is ppresented and the function of all blocks is explained. Notation  to be used in the paper is introduced. Chaotic sequences are defined and explained in accordance with the method of their generation. A wideband channel with frequency selective fading is defined by its impulse response function. Theoretical analysis of a CDMA system with flat fading in a narrowband channel A narrowband channel and flat fading are defined. A mathematical analysis of the system is conducted by presenting the signal expressions at vital points in the transmitter and receiver. The expression of the signal at the output of the sequence correlator is

  17. On the scalability of uncoordinated multiple access for the Internet of Things

    KAUST Repository

    Chisci, Giovanni

    2017-11-16

    The Internet of things (IoT) will entail massive number of wireless connections with sporadic traffic patterns. To support the IoT traffic, several technologies are evolving to support low power wide area (LPWA) wireless communications. However, LPWA networks rely on variations of uncoordinated spectrum access, either for data transmissions or scheduling requests, thus imposing a scalability problem to the IoT. This paper presents a novel spatiotemporal model to study the scalability of the ALOHA medium access. In particular, the developed mathematical model relies on stochastic geometry and queueing theory to account for spatial and temporal attributes of the IoT. To this end, the scalability of the ALOHA is characterized by the percentile of IoT devices that can be served while keeping their queues stable. The results highlight the scalability problem of ALOHA and quantify the extend to which ALOHA can support in terms of number of devices, traffic requirement, and transmission rate.

  18. BioZoom: Exploiting Source-Capability Information for Integrated Access to Multiple Bioinformatics Data Sources

    Energy Technology Data Exchange (ETDEWEB)

    Liu, L; Buttler, D; Critchlow, T J; Han, W; Paques, H; Pu, C; Rocco, D

    2003-01-09

    Modern Bioinformatics data sources are widely used by molecular biologists for homology searching and new drug discovery. User-friendly and yet responsive access is one of the most desirable properties for integrated access to the rapidly growing, heterogeneous, and distributed collection of data sources. The increasing volume and diversity of digital information related to bioinformatics (such as genomes, protein sequences, protein structures, etc.) have led to a growing problem that conventional data management systems do not have, namely finding which information sources out of many candidate choices are the most relevant and most accessible to answer a given user query. We refer to this problem as the query routing problem. In this paper we introduce the notation and issues of query routing, and present a practical solution for designing a scalable query routing system based on multi-level progressive pruning strategies. The key idea is to create and maintain source-capability profiles independently, and to provide algorithms that can dynamically discover relevant information sources for a given query through the smart use of source profiles. Compared to the keyword-based indexing techniques adopted in most of the search engines and software, our approach offers fine-granularity of interest matching, thus it is more powerful and effective for handling queries with complex conditions.

  19. BioZone Exploting Source-Capability Information for Integrated Access to Multiple Bioinformatics Data Sources

    Energy Technology Data Exchange (ETDEWEB)

    Liu, L; Buttler, D; Paques, H; Pu, C; Critchlow

    2002-01-28

    Modern Bioinformatics data sources are widely used by molecular biologists for homology searching and new drug discovery. User-friendly and yet responsive access is one of the most desirable properties for integrated access to the rapidly growing, heterogeneous, and distributed collection of data sources. The increasing volume and diversity of digital information related to bioinformatics (such as genomes, protein sequences, protein structures, etc.) have led to a growing problem that conventional data management systems do not have, namely finding which information sources out of many candidate choices are the most relevant and most accessible to answer a given user query. We refer to this problem as the query routing problem. In this paper we introduce the notation and issues of query routing, and present a practical solution for designing a scalable query routing system based on multi-level progressive pruning strategies. The key idea is to create and maintain source-capability profiles independently, and to provide algorithms that can dynamically discover relevant information sources for a given query through the smart use of source profiles. Compared to the keyword-based indexing techniques adopted in most of the search engines and software, our approach offers fine-granularity of interest matching, thus it is more powerful and effective for handling queries with complex conditions.

  20. Internet-based treatment for depression in multiple sclerosis: A randomized controlled trial.

    Science.gov (United States)

    Boeschoten, Rosa E; Dekker, Joost; Uitdehaag, Bernard Mj; Beekman, Aartjan Tf; Hoogendoorn, Adriaan W; Collette, Emma H; Cuijpers, Pim; Nieuwenhuis, Magdalena M; van Oppen, Patricia

    2017-07-01

    Depression in multiple sclerosis (MS) patients is common but may stay untreated. Physical limitations impede face-to-face treatment. Internet-based treatment is therefore a promising tool for treating depression in MS. To investigate effectiveness of a guided Internet-based problem-solving treatment (IPST) for depressed MS patients. MS patients with moderate or severe depressive symptoms were randomly assigned to IPST or a wait list control. Primary outcome was the change in depressive symptoms defined by a change in sum score on the Beck Depression Inventory Second Edition (BDI-II). Assessments took place at baseline (T0), within a week after the intervention (T1), and at 4 months follow-up (T2). Analyses were based on the intention-to-treat principle. A total of 171 patients were randomized to IPST ( n = 85) or a wait list control ( n = 86). T1 was completed by 152 (89%) and T2 by 131 patients (77%). The IPST group and wait list control showed large significant improvements in depressive symptoms, but no differences were found between groups at T1 ( d = 0.23; 95% confidence interval (CI) = (-4.03, 1.08); p = 0.259) and T2 ( d = 0.01; 95% CI = (-2.80, 2.98); p = 0.953). We found no indication that IPST for MS patients with moderate or severe depression is effective in reducing depressive symptoms compared to a waiting list. Large improvements in the wait list control were unexpected and are discussed.

  1. A randomized trial of high-dose vitamin D2 in relapsing-remitting multiple sclerosis.

    Science.gov (United States)

    Stein, M S; Liu, Y; Gray, O M; Baker, J E; Kolbe, S C; Ditchfield, M R; Egan, G F; Mitchell, P J; Harrison, L C; Butzkueven, H; Kilpatrick, T J

    2011-10-25

    Higher latitude, lower ultraviolet exposure, and lower serum 25-hydroxyvitamin D (25OHD) correlate with higher multiple sclerosis (MS) prevalence, relapse rate, and mortality. We therefore evaluated the effects of high-dose vitamin D2 (D2) in MS. Adults with clinically active relapsing-remitting MS (RRMS) were randomized to 6 months' double-blind placebo-controlled high-dose vitamin D2, 6,000 IU capsules, dose adjusted empirically aiming for a serum 25OHD 130-175 nM. All received daily low-dose (1,000 IU) D2 to prevent deficiency. Brain MRIs were performed at baseline, 4, 5, and 6 months. Primary endpoints were the cumulative number of new gadolinium-enhancing lesions and change in the total volume of T2 lesions. Secondary endpoints were Expanded Disability Status Scale (EDSS) score and relapses. Twenty-three people were randomized, of whom 19 were on established interferon or glatiramer acetate (Copaxone) treatment. Median 25OHD rose from 54 to 69 nM (low-dose D2) vs 59 to 120 nM (high-dose D2) (p = 0.002). No significant treatment differences were detected in the primary MRI endpoints. Exit EDSS, after adjustment for entry EDSS, was higher following high-dose D2 than following low-dose D2 (p = 0.05). There were 4 relapses with high-dose D2 vs none with low-dose D2 (p = 0.04). We did not find a therapeutic advantage in RRMS for high-dose D2 over low-dose D2 supplementation. This study provides Class I evidence that high-dose vitamin D2 (targeting 25OHD 130-175 nM), compared to low-dose supplementation (1,000 IU/d), was not effective in reducing MRI lesions in patients with RRMS.

  2. Feasibility and acceptability of a multiple risk factor intervention: The Step Up randomized pilot trial

    Directory of Open Access Journals (Sweden)

    Richards Julie

    2011-03-01

    Full Text Available Abstract Background Interventions are needed which can successfully modify more than one disease risk factor at a time, but much remains to be learned about the acceptability, feasibility, and effectiveness of multiple risk factor (MRF interventions. To address these issues and inform future intervention development, we conducted a randomized pilot trial (n = 52. This study was designed to assess the feasibility and acceptability of the Step Up program, a MRF cognitive-behavioral program designed to improve participants' mental and physical well-being by reducing depressive symptoms, promoting smoking cessation, and increasing physical activity. Methods Participants were recruited from a large health care organization and randomized to receive usual care treatment for depression, smoking, and physical activity promotion or the phone-based Step Up counseling program plus usual care. Participants were assessed at baseline, three and six months. Results The intervention was acceptable to participants and feasible to offer within a healthcare system. The pilot also offered important insights into the optimal design of a MRF program. While not powered to detect clinically significant outcomes, changes in target behaviors indicated positive trends at six month follow-up and statistically significant improvement was also observed for depression. Significantly more experimental participants reported a clinically significant improvement (50% reduction in their baseline depression score at four months (54% vs. 26%, OR = 3.35, 95% CI [1.01- 12.10], p = 0.05 and 6 months (52% vs. 13%, OR = 7.27, 95% CI [1.85 - 37.30], p = 0.004 Conclusions Overall, results suggest the Step Up program warrants additional research, although some program enhancements may be beneficial. Key lessons learned from this research are shared to promote the understanding of others working in this field. Trial registration The trial is registered with ClinicalTrials.gov (NCT00644995.

  3. Multiple choice exams of medical knowledge with open books and web access? A validity study

    DEFF Research Database (Denmark)

    O'Neill, Lotte; Simonsen, Eivind Ortind; Knudsen, Ulla Breth

    2015-01-01

    Background: Open book tests have been suggested to lower test anxiety and promote deeper learning strategies. In the Aarhus University medical program, ¼ of the curriculum assess students’ medical knowledge with ‘open book, open web’ (OBOW) multiple choice examinations. We found little existing...

  4. All-optical differential detection for suppressing multiple-access interference in coherent time-addressed optical CDMA systems.

    Science.gov (United States)

    Kim, Sun-Jong; Kim, Tae-Young; Park, Chul; Park, Chang-Soo; Chun, Young

    2004-05-03

    A novel scheme for suppressing the multiple-access interference (MAI) in coherent time-addressed optical CDMA systems is proposed. This is based on a differential detection using the dual-control NOLM. The basic principle for MAI suppression is described. For experimental demonstration, two encoded channels are constructed and decoded. These decoded signals are sent to the dual-control NOLM and a high autocorrelation peak with suppressed MAI at the output of NOLM is observed. Signal-to-interference ratio is improved by 7 dB.

  5. Joint estimation and contention-resolution protocol for wireless random access

    DEFF Research Database (Denmark)

    Stefanovic, Cedomir; Trillingsgaard, Kasper Fløe; Kiilerich Pratas, Nuno

    2013-01-01

    successive interference cancellation which, coupled with the use of the optimized access probabilities, enables throughputs that are substantially higher than the traditional slotted ALOHA-like protocols. The key feature of the proposed protocol is that the round durations are not a priori set...

  6. Persons with Multiple Disabilities Access Stimulation and Contact the Caregiver via Microswitch and VOCA Technology

    Directory of Open Access Journals (Sweden)

    Giulio E. Lancioni

    2009-12-01

    Full Text Available We assessed whether eight persons (children and adolescents with multipledisabilities would succeed in combining the use of a microswitch and aVOCA. The microswitch served to gain direct access to selected environmentalstimuli and the VOCA served to contact the caregiver and obtainher social attention or mediation toward other forms of stimulation. Thestudy also included a social validation assessment of the aforementionedmicroswitch-VOCA combination. Data showed that participants couldlearn to use the microswitch and the VOCA profitably. The social validationassessment showed that 64 university psychology students and 64 postgraduateclinical trainees employed as raters favored the combination ofmicroswitch and VOCA over the microswitch and the VOCA alone.

  7. Effects of multidisciplinary rehabilitation on chronic fatigue in multiple sclerosis: a randomized controlled trial.

    Science.gov (United States)

    Rietberg, Marc B; van Wegen, Erwin E H; Eyssen, Isaline C J M; Kwakkel, Gert

    2014-01-01

    Several rehabilitation programmes aim at reducing the impact of fatigue in MS patients. Acute and chronic fatigue should require different management. To assess the effects of individually tailored, multidisciplinary outpatient rehabilitation (MDR) on chronic fatigue. Forty-eight ambulatory MS patients with chronic fatigue were randomized to MDR or to MS-nurse consultation. Fatigue was assessed by the Checklist Individual Strength (CIS-20R). Secondary outcomes included the Modified Fatigue Impact Scale, Fatigue Severity Scale, Functional Independence Measure, Disability and Impact Profile (DIP), Multiple Sclerosis Impact Scale and the Impact on Participation and Autonomy (IPA). The primary outcome measure CIS-20R overall score showed no significant differences between groups at 12 weeks (P = 0.39) and 24 weeks follow-up (P = 0.14), nor for subscales (t = 12 and t = 24, 0.19≤P≤0.88). No significant within-group effects were found for both groups with respect to the primary (0.57≤p≤0.97) and secondary (0.11≤p≤0.92) outcome measures from baseline to 12 or 24 weeks. Multidisciplinary rehabilitation was not more effective in terms of reducing self-reported fatigue in MS patients compared to MS-nurse consultation. Our results suggest that chronic fatigue in patients with MS may be highly invariant over time, irrespective of interventions. controlled-trials.com ISRCTN05017507.

  8. On the estimation of multiple random integrals and U-statistics

    CERN Document Server

    Major, Péter

    2013-01-01

    This work starts with the study of those limit theorems in probability theory for which classical methods do not work. In many cases some form of linearization can help to solve the problem, because the linearized version is simpler. But in order to apply such a method we have to show that the linearization causes a negligible error. The estimation of this error leads to some important large deviation type problems, and the main subject of this work is their investigation. We provide sharp estimates of the tail distribution of multiple integrals with respect to a normalized empirical measure and so-called degenerate U-statistics and also of the supremum of appropriate classes of such quantities. The proofs apply a number of useful techniques of modern probability that enable us to investigate the non-linear functionals of independent random variables. This lecture note yields insights into these methods, and may also be useful for those who only want some new tools to help them prove limit theorems when stand...

  9. Teriflunomide added to interferon-β in relapsing multiple sclerosis: a randomized phase II trial.

    Science.gov (United States)

    Freedman, M S; Wolinsky, J S; Wamil, B; Confavreux, C; Comi, G; Kappos, L; Olsson, T P; Miller, A; Benzerdjeb, H; Li, H; Simonson, C; O'Connor, P W

    2012-06-05

    To evaluate teriflunomide as add-on therapy to ongoing stable-dosed interferon-β (IFNβ) in patients with relapsing forms of multiple sclerosis (RMS). A total of 118 patients with RMS were randomly assigned 1:1:1 to receive oral placebo or teriflunomide, 7 or 14 mg, once daily for 24 weeks; 86 patients entered the 24-week extension. The primary objective was to evaluate safety; secondary objectives were to evaluate the effects of treatment on disease activity assessed by MRI and relapse rate. Teriflunomide was well tolerated with a low and similar incidence of treatment-emergent adverse events (TEAEs) across the 3 groups; TEAEs led to treatment discontinuation of 4.9%, 8.1%, and 7.9% of patients in the placebo, 7-mg, and 14-mg groups, respectively. The number of gadolinium-enhancing T1 (T1-Gd) lesions was reduced in both teriflunomide groups, with relative risk reductions (RRRs) of 84.6% (p = 0.0005) and 82.8% (p Teriflunomide as add-on therapy to IFNβ had acceptable safety and tolerability and reduced MRI disease activity compared with IFNβ alone. This study provides Class II evidence that teriflunomide, 7 and 14 mg, added to IFNβ, is safe. The T1-Gd lesion burden was significantly reduced with both teriflunomide doses.

  10. Hippotherapy for patients with multiple sclerosis: A multicenter randomized controlled trial (MS-HIPPO).

    Science.gov (United States)

    Vermöhlen, Vanessa; Schiller, Petra; Schickendantz, Sabine; Drache, Marion; Hussack, Sabine; Gerber-Grote, Andreas; Pöhlau, Dieter

    2017-08-01

    Evidence-based complementary treatment options for multiple sclerosis (MS) are limited. To investigate the effect of hippotherapy plus standard care versus standard care alone in MS patients. A total of 70 adults with MS were recruited in five German centers and randomly allocated to the intervention group (12 weeks of hippotherapy) or the control group. Primary outcome was the change in the Berg Balance Scale (BBS) after 12 weeks, and further outcome measures included fatigue, pain, quality of life, and spasticity. Covariance analysis of the primary endpoint resulted in a mean difference in BBS change of 2.33 (95% confidence interval (CI): 0.03-4.63, p = 0.047) between intervention ( n = 32) and control ( n = 38) groups. Benefit on BBS was largest for the subgroup with an Expanded Disability Status Scale (EDSS) ⩾ 5 (5.1, p = 0.001). Fatigue (-6.8, p = 0.02) and spasticity (-0.9, p = 0.03) improved in the intervention group. The mean difference in change between groups was 12.0 ( p Hippotherapy plus standard care, while below the threshold of a minimal clinically important difference, significantly improved balance and also fatigue, spasticity, and quality of life in MS patients.

  11. The effects of robot-assisted gait training in progressive multiple sclerosis: A randomized controlled trial.

    Science.gov (United States)

    Straudi, Sofia; Fanciullacci, Chiara; Martinuzzi, Carlotta; Pavarelli, Claudia; Rossi, Bruno; Chisari, Carmelo; Basaglia, Nino

    2016-03-01

    Gait and mobility impairments are common in progressive multiple sclerosis (MS), leading to reduced quality of life (QoL). In this randomized controlled study, we tested the effects of robot-assisted gait training (RAGT) and compared it to conventional physiotherapy, measuring walking ability, depression, fatigue, and QoL in patients with progressive MS and severe gait disability. Fifty-two participants (Expanded Disability Status Scale score 6-7) completed the study protocol. They received two sessions/week over 6 weeks of RAGT or conventional walking therapy. Outcome measures were Six-Minute Walk Test, Ten-Meter Walk Test, Timed Up and Go Test, Berg Balance Scale, Fatigue Severity Scale, Patient Health Questionnaire, and Short Form 36. They were performed pre-treatment, post-treatment, and at 3 months. Walking endurance (p physical functioning QoL increased. No significant effects on fatigue were found. RAGT is a treatment option in progressive MS patients with severe gait impairments to induce short-lasting effects on mobility and QoL. © The Author(s), 2015.

  12. Increased statistical power with combined independent randomization tests used with multiple-baseline design.

    Science.gov (United States)

    Tyrrell, Pascal N; Corey, Paul N; Feldman, Brian M; Silverman, Earl D

    2013-06-01

    Physicians often assess the effectiveness of treatments on a small number of patients. Multiple-baseline designs (MBDs), based on the Wampold-Worsham (WW) method of randomization and applied to four subjects, have relatively low power. Our objective was to propose another approach with greater power that does not suffer from the time requirements of the WW method applied to a greater number of subjects. The power of a design that involves the combination of two four-subject MBDs was estimated using computer simulation and compared with the four- and eight-subject designs. The effect of a delayed linear response to treatment on the power of the test was also investigated. Power was found to be adequate (>80%) for a standardized mean difference (SMD) greater than 0.8. The effect size associated with 80% power from combined tests was smaller than that of the single four-subject MBD (SMD=1.3) and comparable with the eight-subject MBD (SMD=0.6). A delayed linear response to the treatment resulted in important reductions in power (20-35%). By combining two four-subject MBD tests, an investigator can detect better effect sizes (SMD=0.8) and be able to complete a comparatively timelier and feasible study. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. A randomized placebo-controlled phase III trial of oral laquinimod for multiple sclerosis

    DEFF Research Database (Denmark)

    Vollmer, T L; Sorensen, P S; Selmaj, K

    2014-01-01

    using EDSS was -31 % [hazard ratio (HR) 0.69, p = 0.063], and using Multiple Sclerosis Functional Composite (MSFC) z-score was -77 % (p = 0.150), vs. placebo. IFNβ-1a reduced ARR 26 % (RR = 0.74, 95 % CI 0.60-0.92, p = 0.007), showed no effect on PBVC loss (+11 %, p = 0.14), and changes in disability......The phase III placebo-controlled BRAVO study assessed laquinimod effects in patients with relapsing-remitting MS (RRMS), and descriptively compared laquinimod with interferon beta (IFNβ)-1a (Avonex(®) reference arm). RRMS patients age 18-55 years with Expanded Disability Status Scale (EDSS) scores...... months. The primary endpoint was annualized relapse rate (ARR); secondary endpoints included percent brain volume change (PBVC) and 3-month confirmed disability worsening. In all, 1,331 patients were randomized: laquinimod (n = 434), placebo (n = 450), and IFNβ-1a (n = 447). ARR was not significantly...

  14. A prospective randomized trial examining health care utilization in individuals using multiple smartphone-enabled biosensors

    Directory of Open Access Journals (Sweden)

    Cinnamon S. Bloss

    2016-01-01

    Full Text Available Background. Mobile health and digital medicine technologies are becoming increasingly used by individuals with common, chronic diseases to monitor their health. Numerous devices, sensors, and apps are available to patients and consumers–some of which have been shown to lead to improved health management and health outcomes. However, no randomized controlled trials have been conducted which examine health care costs, and most have failed to provide study participants with a truly comprehensive monitoring system. Methods. We conducted a prospective randomized controlled trial of adults who had submitted a 2012 health insurance claim associated with hypertension, diabetes, and/or cardiac arrhythmia. The intervention involved receipt of one or more mobile devices that corresponded to their condition(s (hypertension: Withings Blood Pressure Monitor; diabetes: Sanofi iBGStar Blood Glucose Meter; arrhythmia: AliveCor Mobile ECG and an iPhone with linked tracking applications for a period of 6 months; the control group received a standard disease management program. Moreover, intervention study participants received access to an online health management system which provided participants detailed device tracking information over the course of the study. This was a monitoring system designed by leveraging collaborations with device manufacturers, a connected health leader, health care provider, and employee wellness program–making it both unique and inclusive. We hypothesized that health resource utilization with respect to health insurance claims may be influenced by the monitoring intervention. We also examined health-self management. Results & Conclusions. There was little evidence of differences in health care costs or utilization as a result of the intervention. Furthermore, we found evidence that the control and intervention groups were equivalent with respect to most health care utilization outcomes. This result suggests there are not large

  15. Ultrasonic Multiple-Access Ranging System Using Spread Spectrum and MEMS Technology for Indoor Localization

    Directory of Open Access Journals (Sweden)

    Laurent Segers

    2014-02-01

    Full Text Available Indoor localization of persons and objects poses a great engineering challenge. Previously developed localization systems demonstrate the use of wideband techniques in ultrasound ranging systems. Direct sequence and frequency hopping spread spectrum ultrasound signals have been proven to achieve a high level of accuracy. A novel ranging method using the frequency hopping spread spectrum with finite impulse response filtering will be investigated and compared against the direct sequence spread spectrum. In the first setup, distances are estimated in a single-access environment, while in the second setup, two senders and one receiver are used. During the experiments, the micro-electromechanical systems are used as ultrasonic sensors, while the senders were implemented using field programmable gate arrays. Results show that in a single-access environment, the direct sequence spread spectrum method offers slightly better accuracy and precision performance compared to the frequency hopping spread spectrum. When two senders are used, measurements point out that the frequency hopping spread spectrum is more robust to near-far effects than the direct sequence spread spectrum.

  16. Multiple-wavelength double random phase encoding with CCD-plane sparse-phase multiplexing for optical information verification.

    Science.gov (United States)

    Chen, Wen

    2015-12-20

    A novel method is proposed by using multiple-wavelength double random phase encoding (MW-DRPE) with CCD-plane sparse-phase multiplexing for optical information verification. Two different strategies are applied to conduct sparse-phase multiplexing in the CCD plane. The results demonstrate that large capacity can be achieved for optical multiple-image verification. The proposed optical verification strategy is implemented based on optical encoding, and the keys generated by optical encryption can further guarantee the safety of the designed optical multiple-image verification system. The proposed method provides a novel alternative for DRPE-based optical information verification.

  17. WATER TEMPERATURE and Other Data from MULTIPLE SHIPS From NE Atlantic (limit-40 W) and Others from 19500831 to 19881231 (NODC Accession 9200060)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains contains chlorophyll data collected from 1958-1988 using multiple ships. Marine pigments, productivity, and associated chemistry data were...

  18. WATER TEMPERATURE and other data from MULTIPLE SHIPS from 1983-01-01 to 1992-12-31 (NODC Accession 9400224)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains data collected as part of Shipboard Environmental data Acquisition System (SEAS) II program. The cruises were conducted using multiple ships....

  19. CAS (CHEMICAL ABSTRACTS SOCIETY) PARAMETER CODES and Other Data from MULTIPLE SHIPS From Caribbean Sea and Others from 19790205 to 19890503 (NCEI Accession 9100017)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The accession contains Chemical Abstracts Society (CAS) parameter codes and Other Data from MULTIPLE SHIPS From Caribbean Sea and Gulf of Mexico from February 5,...

  20. SALINITY and WATER TEMPERATURE and other data from MULTIPLE SHIPS from 1985-02-22 to 1989-12-16 (NODC Accession 9300103)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data in this accession is dynamic height data collected from line Islands array using multiple ships. The data was collected by Graduate School of Oceanography,...

  1. Oceanographic profile data collected aboard multiple platforms worldwide from 1959-05-26 to 2012-06-03 (NCEI Accession 0098794)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0098794 contains physical and chemical oceanographic profile data collected aboard multiple ships worldwide from 1959-05-26 to 2012-06-03. These data...

  2. Performance of a Frequency-Hopped Real-Time Remote Control System in a Multiple Access Scenario

    Science.gov (United States)

    Cervantes, Frank

    A recent trend is observed in the context of the radio-controlled aircrafts and automobiles within the hobby grade category and Unmanned Aerial Vehicles (UAV) applications moving to the well-known Industrial, Scientific and Medical (ISM) band. Based on this technological fact, the present thesis evaluates an individual user performance by featuring a multiple-user scenario where several point-to-point co-located real-time Remote Control (RC) applications operate using Frequency Hopping Spread Spectrum (FHSS) as a medium access technique in order to handle interference efficiently. Commercial-off-the-shelf wireless transceivers ready to operate in the ISM band are considered as the operational platform supporting the above-mentioned applications. The impact of channel impairments and of different critical system engineering issues, such as working with real clock oscillators and variable packet duty cycle, are considered. Based on the previous, simulation results allowed us to evaluate the range of variation for those parameters for an acceptable system performance under Multiple Access (MA) environments.

  3. Multiple-access interference in 2-D wavelength/time optical CDMA system with optical hard-limiters

    Science.gov (United States)

    Chovan, Jozef; Uherek, František

    2005-08-01

    In this paper we present the proposed modification of 2-D wavelength/time (WIT) decoder1 by placing the second optical hard-limiter (0-HL) after decoder"s last optical coupler. The MA1 improvement of the 2-D W/T Optical Code Division Multiple Access (0-CDMA) system for the cases of 2D WIT decoder with one and with two 0-HLs is analyzed. Average value of signal-to-interference difference (SID) is used as the MA1 merit. The model of such 2D W/T 0-CDMA system for numerical calculation of the SID is proposed and presented in this paper. In the analyzed system, 2-D WIT Generalized Multiwavelength Prime Codewords (GMWPC), which are generated by algorithm reported in2 are used for achieving multiple-access. We assume the implemented 0-HL proposed in 3. The properties of such 0-HL were approximated [4] and its two ideality parameters, which characterize the measure of its ideality, were defined. The input and output time optical pulses sequence of W/T 0-CDMA decoder is numerical simulated. Dependencies of SID versus the weight of codeword and the number of active users in the system are presented. The influence of the properties used 0-HLs is evaluated.

  4. ECR Browser: A Tool For Visualizing And Accessing Data From Comparisons Of Multiple Vertebrate Genomes

    Energy Technology Data Exchange (ETDEWEB)

    Loots, G G; Ovcharenko, I; Stubbs, L; Nobrega, M A

    2004-01-06

    The increasing number of vertebrate genomes being sequenced in draft or finished form provide a unique opportunity to study and decode the language of DNA sequence through comparative genome alignments. However, novel tools and strategies are required to accommodate this increasing volume of genomic information and to facilitate experimental annotation of genome function. Here we present the ECR Browser, a tool that provides an easy and dynamic access to whole genome alignments of human, mouse, rat and fish sequences. This web-based tool (http://ecrbrowser.dcode.org) provides the starting point for discovery of novel genes, identification of distant gene regulatory elements and prediction of transcription factor binding sites. The genome alignment portal of the ECR Browser also permits fast and automated alignment of any user-submitted sequence to the genome of choice. The interconnection of the ECR browser with other DNA sequence analysis tools creates a unique portal for studying and exploring vertebrate genomes.

  5. Capacity bounds for the 2-user Gaussian IM-DD optical multiple-access channel

    KAUST Repository

    Al-Ebraheemy, Omer M. S.

    2016-11-01

    Optical wireless communications (OWC) is a potential solution for coping with the mismatch between the users growing demand for higher data-rates and the wireless network capabilities. In this paper, a multi-user OWC scenario is studied from an in formation-theoretic perspective. The studied network consists of two users communicating simultaneously with one access point using OWC, thus establishing an optical uplink channel. The capacity of this network is an important metric which reflects the highest possible communication rates that can be achieved over this channel. Capacity outer and inner bounds are derived, and are shown to be fairly tight in the high signal-to-noise ratio regime. © 2016 IEEE.

  6. Access to Care for Multiple Sclerosis in Times of Economic Crisis in Greece--the HOPE II Study.

    Science.gov (United States)

    Souliotis, Kyriakos; Alexopoulou, Elena; Papageorgiou, Manto; Politi, Anastasia; Litsa, Panagiota; Contiades, Xenophon

    2015-09-27

    While there is currently no cure for multiple sclerosis (MS), treatment with biologic disease-modifying drugs (bDMDs) can reduce the impact of the condition on the lives of patients. In Greece, the regulatory change in the distribution system of bDMDs, limited their administration through the designated pharmacies of the National Organization for Healthcare Services Provision (EOPYY) or the National Health System (ESY) hospitals, thus potentially impacting access to MS treatment. In this context, the aim of this paper was to assess the barriers to bDMDs, by recording MS patients' experiences. A survey research was conducted between January and February 2014 in Athens and 5 other major Greek cities with the methods of personal and telephone interview. A structured questionnaire was used to elicit socio-economic and medical information, information related to obstacles in accessing bDMDs and medical treatment, from MS patients that visited EOPYY pharmacies during the study period. During the last year 69% of 179 participants reported that the distribution system of bDMDs has improved. Thirteen percent of participants encountered problems in accessing their medication, and 16.9% of participants in accessing their physician, with the obstacles being more pronounced for non-Athens residents. Frequent obstacles to bDMDs were the distance from EOPYY pharmacies and difficulties in obtaining a diagnosis from an EOPYY/ESY physician, while obstacles to medical care were delays in appointment booking and travel difficulties. Even though the major weaknesses of the distribution system of bDMDs have improved, further amelioration of the system could be achieved through the home delivery of medicines to patients living in remote areas, and through the development of a national MS registry. © 2016 by Kerman University of Medical Sciences.

  7. Access to Care for Multiple Sclerosis in Times of Economic Crisis in Greece – the HOPE II Study

    Directory of Open Access Journals (Sweden)

    Kyriakos Souliotis

    2016-02-01

    Full Text Available Background While there is currently no cure for multiple sclerosis (MS, treatment with biologic diseasemodifying drugs (bDMDs can reduce the impact of the condition on the lives of patients. In Greece, the regulatory change in the distribution system of bDMDs, limited their administration through the designated pharmacies of the National Organization for Healthcare Services Provision (EOPYY or the National Health System (ESY hospitals, thus potentially impacting access to MS treatment. In this context, the aim of this paper was to assess the barriers to bDMDs, by recording MS patients’ experiences. Methods A survey research was conducted between January and February 2014 in Athens and 5 other major Greek cities with the methods of personal and telephone interview. A structured questionnaire was used to elicit socio-economic and medical information, information related to obstacles in accessing bDMDs and medical treatment, from MS patients that visited EOPYY pharmacies during the study period. Results During the last year 69% of 179 participants reported that the distribution system of bDMDs has improved. Thirteen percent of participants encountered problems in accessing their medication, and 16.9% of participants in accessing their physician, with the obstacles being more pronounced for non-Athens residents. Frequent obstacles to bDMDs were the distance from EOPYY pharmacies and difficulties in obtaining a diagnosis from an EOPYY/ESY physician, while obstacles to medical care were delays in appointment booking and travel difficulties. Conclusion Even though the major weaknesses of the distribution system of bDMDs have improved, further amelioration of the system could be achieved through the home delivery of medicines to patients living in remote areas, and through the development of a national MS registry.

  8. Stabilometric assessment of context dependent balance recovery in persons with multiple sclerosis: a randomized controlled study.

    Science.gov (United States)

    Cattaneo, Davide; Jonsdottir, Johanna; Regola, Alberto; Carabalona, Roberta

    2014-06-10

    Balance control relies on accurate perception of visual, somatosensory and vestibular cues. Sensory flow is impaired in Multiple Sclerosis (MS) and little is known about the ability of the sensory systems to adapt after neurological lesions reducing sensory impairment. The aims of the present study were to verify whether: 1. Balance rehabilitation administered in a challenging sensory conditions would improve stability in upright posture. 2. The improvement in a treated sensory condition would transfer to a non treated sensory condition. Fifty three persons with MS, median (min-max) EDSS score of 5 (2.5-6.5), participated in a RCT and were randomly assigned to two groups. The Experimental group received balance rehabilitation aimed at improving motor and sensory strategies. The Control group received rehabilitation treatment which did not include training of sensory strategies. Persons with MS were blindly assessed by means of a stabilometric platform with eyes open, eyes closed and dome, on both firm surface and foam. Anterior-posterior and medio-lateral sway, velocity of sway and the length of Center of Pressure (CoP) trajectory were calculated in the six sensory conditions. Experimental group showed statistically significant improvement (P stability in upright posture in eyes closed condition on firm surface, and in eyes open, closed, and dome conditions on foam. No differences were observed between groups in the eyes open condition on firm surface nor in the sensory condition not addressed during the treatment. After rehabilitation people with MS can recover from sensory impairments thus improving upright balance. Further, the improvement seems to be context-dependent and present just in the treated sensory conditions. ClinicalTrials NCT02131285.

  9. A comparison of random forest regression and multiple linear regression for prediction in neuroscience.

    Science.gov (United States)

    Smith, Paul F; Ganesh, Siva; Liu, Ping

    2013-10-30

    Regression is a common statistical tool for prediction in neuroscience. However, linear regression is by far the most common form of regression used, with regression trees receiving comparatively little attention. In this study, the results of conventional multiple linear regression (MLR) were compared with those of random forest regression (RFR), in the prediction of the concentrations of 9 neurochemicals in the vestibular nucleus complex and cerebellum that are part of the l-arginine biochemical pathway (agmatine, putrescine, spermidine, spermine, l-arginine, l-ornithine, l-citrulline, glutamate and γ-aminobutyric acid (GABA)). The R(2) values for the MLRs were higher than the proportion of variance explained values for the RFRs: 6/9 of them were ≥ 0.70 compared to 4/9 for RFRs. Even the variables that had the lowest R(2) values for the MLRs, e.g. ornithine (0.50) and glutamate (0.61), had much lower proportion of variance explained values for the RFRs (0.27 and 0.49, respectively). The RSE values for the MLRs were lower than those for the RFRs in all but two cases. In general, MLRs seemed to be superior to the RFRs in terms of predictive value and error. In the case of this data set, MLR appeared to be superior to RFR in terms of its explanatory value and error. This result suggests that MLR may have advantages over RFR for prediction in neuroscience with this kind of data set, but that RFR can still have good predictive value in some cases. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Virtual rehabilitation for multiple sclerosis using a kinect-based system: randomized controlled trial.

    Science.gov (United States)

    Lozano-Quilis, Jose-Antonio; Gil-Gómez, Hermenegildo; Gil-Gómez, Jose-Antonio; Albiol-Pérez, Sergio; Palacios-Navarro, Guillermo; Fardoun, Habib M; Mashat, Abdulfattah S

    2014-11-12

    The methods used for the motor rehabilitation of patients with neurological disorders include a number of different rehabilitation exercises. For patients who have been diagnosed with multiple sclerosis (MS), the performance of motor rehabilitation exercises is essential. Nevertheless, this rehabilitation may be tedious, negatively influencing patients' motivation and adherence to treatment. We present RemoviEM, a system based on Kinect that uses virtual reality (VR) and natural user interfaces (NUI) to offer patients with MS an intuitive and motivating way to perform several motor rehabilitation exercises. It offers therapists a new motor rehabilitation tool for the rehabilitation process, providing feedback on the patient's progress. Moreover, it is a low-cost system, a feature that can facilitate its integration in clinical rehabilitation centers. A randomized and controlled single blinded study was carried out to assess the influence of a Kinect-based virtual rehabilitation system on the balance rehabilitation of patients with MS. This study describes RemoviEM and evaluates its effectiveness compared to standard rehabilitation. To achieve this objective, a clinical trial was carried out. Eleven patients from a MS association participated in the clinical trial. The mean age was 44.82 (SD 10.44) and the mean time from diagnosis (years) was 9.77 (SD 10.40). Clinical effectiveness was evaluated using clinical balance scales. Significant group-by-time interaction was detected in the scores of the Berg Balance Scale (P=.011) and the Anterior Reach Test in standing position (P=.011). Post-hoc analysis showed greater improvement in the experimental group for these variables than in the control group for these variables. The Suitability Evaluation Questionnaire (SEQ) showed good results in usability, acceptance, security, and safety for the evaluated system. The results obtained suggest that RemoviEM represents a motivational and effective alternative to traditional

  11. IPAT: a freely accessible software tool for analyzing multiple patent documents with inbuilt landscape visualizer.

    Science.gov (United States)

    Ajay, Dara; Gangwal, Rahul P; Sangamwar, Abhay T

    2015-01-01

    Intelligent Patent Analysis Tool (IPAT) is an online data retrieval tool, operated based on text mining algorithm to extract specific patent information in a predetermined pattern into an Excel sheet. The software is designed and developed to retrieve and analyze technology information from multiple patent documents and generate various patent landscape graphs and charts. The software is C# coded in visual studio 2010, which extracts the publicly available patent information from the web pages like Google Patent and simultaneously study the various technology trends based on user-defined parameters. In other words, IPAT combined with the manual categorization will act as an excellent technology assessment tool in competitive intelligence and due diligence for predicting the future R&D forecast.

  12. Multiple social identities and stereotype threat: imbalance, accessibility, and working memory.

    Science.gov (United States)

    Rydell, Robert J; McConnell, Allen R; Beilock, Sian L

    2009-05-01

    In 4 experiments, the authors showed that concurrently making positive and negative self-relevant stereotypes available about performance in the same ability domain can eliminate stereotype threat effects. Replicating past work, the authors demonstrated that introducing negative stereotypes about women's math performance activated participants' female social identity and hurt their math performance (i.e., stereotype threat) by reducing working memory. Moving beyond past work, it was also demonstrated that concomitantly presenting a positive self-relevant stereotype (e.g., college students are good at math) increased the relative accessibility of females' college student identity and inhibited their gender identity, eliminating attendant working memory deficits and contingent math performance decrements. Furthermore, subtle manipulations in questions presented in the demographic section of a math test eliminated stereotype threat effects that result from women reporting their gender before completing the test. This work identifies the motivated processes through which people's social identities became active in situations in which self-relevant stereotypes about a stigmatized group membership and a nonstigmatized group membership were available. In addition, it demonstrates the downstream consequences of this pattern of activation on working memory and performance. Copyright (c) 2009 APA, all rights reserved.

  13. On Low-Complexity Full-diversity Detection In Multi-User MIMO Multiple-Access Channels

    KAUST Repository

    Ismail, Amr

    2014-01-28

    Multiple-input multiple-output (MIMO) techniques are becoming commonplace in recent wireless communication standards. This newly introduced dimension (i.e., space) can be efficiently used to mitigate the interference in the multi-user MIMO context. In this paper, we focus on the uplink of a MIMO multiple access channel (MAC) where perfect channel state information (CSI) is only available at the destination. We provide new sufficient conditions for a wide range of space-time block codes (STBC)s to achieve full-diversity under partial interference cancellation group decoding (PICGD) with or without successive interference cancellation (SIC) for completely blind users. Interference cancellation (IC) schemes for two and three users are then provided and shown to satisfy the full-diversity criteria. Beside the complexity reduction due to the fact that PICGD enables separate decoding of distinct users without sacrificing the diversity gain, further reduction of the decoding complexity may be obtained. In fact, thanks to the structure of the proposed schemes, the real and imaginary parts of each user\\'s symbols may be decoupled without any loss of performance. Our new IC scheme is shown to outperform recently proposed two-user IC scheme especially for high spectral efficiency while requiring significantly less decoding complexity.

  14. Post-Coma Persons with Extensive Multiple Disabilities Use Microswitch Technology to Access Selected Stimulus Events or Operate a Radio Device

    Science.gov (United States)

    Lancioni, Giulio E.; Singh, Nirbhay N.; O'Reilly, Mark F.; Sigafoos, Jeff; Alberti, Gloria; Oliva, Doretta; Megna, Gianfranco; Iliceto, Carla; Damiani, Sabino; Ricci, Irene; Spica, Antonella

    2011-01-01

    The present two studies extended research evidence on the use of microswitch technology by post-coma persons with multiple disabilities. Specifically, Study I examined whether three adults with a diagnosis of minimally conscious state and multiple disabilities could use microswitches as tools to access brief, selected stimulus events. Study II…

  15. Optimal Throughput and Energy Efficiency for Wireless Sensor Networks: Multiple Access and Multipacket Reception

    Directory of Open Access Journals (Sweden)

    Li Wenjun

    2005-01-01

    Full Text Available We investigate two important aspects in sensor network design—the throughput and the energy efficiency. We consider the uplink reachback problem where the receiver is equipped with multiple antennas and linear multiuser detectors. We first assume Rayleigh flat-fading, and analyze two MAC schemes: round-robin and slotted-ALOHA. We optimize the average number of transmissions per slot and the transmission power for two purposes: maximizing the throughput, or minimizing the effective energy (defined as the average energy consumption per successfully received packet subject to a throughput constraint. For each MAC scheme with a given linear detector, we derive the maximum asymptotic throughput as the signal-to-noise ratio goes to infinity. It is shown that the minimum effective energy grows rapidly as the throughput constraint approaches the maximum asymptotic throughput. By comparing the optimal performance of different MAC schemes equipped with different detectors, we draw important tradeoffs involved in the sensor network design. Finally, we show that multiuser scheduling greatly enhances system performance in a shadow fading environment.

  16. Family Access to a Dentist Study (FADS): A Multi-Center Randomized Controlled Trial

    Science.gov (United States)

    Nelson, Suchitra; Riedy, Christine; Albert, Jeffrey M; Lee, Wonik; Slusar, Mary Beth; Curtan, Shelley; Ferretti, Gerald; Cunha-Cruz, Joana; Milgrom, Peter

    2015-01-01

    Introduction Many low-income parent/caregivers do not understand the importance of cavity-free primary (baby) teeth and the chronic nature of dental caries (tooth decay). As a consequence, dental preventive and treatment utilization is low even when children are screened in schools and referred for care. This study aims to test a referral letter and Dental Information Guide (DIG) designed using the Common-Sense Model of Self-Regulation (CSM) framework to improve caregivers’ illness perception of dental caries and increase utilization of care by children with restorative dental needs. Methods A multi-site randomized controlled trial with caregivers of Kindergarten to 4th grade children in urban Ohio and rural Washington State will compare five arms: (1) CSM referral letter alone; (2) CSM referral letter + DIG; (3) reduced CSM referral letter alone; (4) reduced CSM referral letter + DIG; (5) standard (control) referral. At baseline, children will be screened at school to determine restorative dental needs. If in need of treatment, caregivers will be randomized to study arms and an intervention packet will be sent home. The primary outcome will be dental care based on a change in oral health status by clinical examination 7 months post-screening (ICDAS sealant codes 1 and 2; restoration codes 3–8; extraction). Enrollment commenced summer 2015 with results in summer 2016. Conclusion This study uses the CSM framework to develop and test behavioral interventions to increase dental utilization among low-income caregivers. If effective this simple intervention has broad applicability in clinical and community-based settings. PMID:26500170

  17. Family Access to a Dentist Study (FADS): A multi-center randomized controlled trial.

    Science.gov (United States)

    Nelson, Suchitra; Riedy, Christine; Albert, Jeffrey M; Lee, Wonik; Slusar, Mary Beth; Curtan, Shelley; Ferretti, Gerald; Cunha-Cruz, Joana; Milgrom, Peter

    2015-11-01

    Many low-income parent/caregivers do not understand the importance of cavity-free primary (baby) teeth and the chronic nature of dental caries (tooth decay). As a consequence, dental preventive and treatment utilization is low even when children are screened in schools and referred for care. This study aims to test a referral letter and Dental Information Guide (DIG) designed using the Common-Sense Model of Self-Regulation (CSM) framework to improve caregivers' illness perception of dental caries and increase utilization of care by children with restorative dental needs. A multi-site randomized controlled trial with caregivers of Kindergarten to 4th grade children in urban Ohio and rural Washington State will compare five arms: (1) CSM referral letter alone; (2) CSM referral letter+DIG; (3) reduced CSM referral letter alone; (4) reduced CSM referral letter+DIG; and (5) standard (control) referral. At baseline, children will be screened at school to determine restorative dental needs. If in need of treatment, caregivers will be randomized to study arms and an intervention packet will be sent home. The primary outcome will be dental care based on a change in oral health status by clinical examination 7 months post-screening (ICDAS sealant codes 1 and 2; restoration codes 3-8; extraction). Enrollment commenced summer 2015 with results in summer 2016. This study uses the CSM framework to develop and test behavioral interventions to increase dental utilization among low-income caregivers. If effective this simple intervention has broad applicability in clinical and community-based settings. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Performance analysis for a chaos-based code-division multiple access system in wide-band channel

    Directory of Open Access Journals (Sweden)

    Ciprian Doru Giurcăneanu

    2015-08-01

    Full Text Available Code-division multiple access technology is widely used in telecommunications and its performance has been extensively investigated in the past. Theoretical results for the case of wide-band transmission channel were not available until recently. The novel formulae which have been published in 2014 can have an important impact on the future of wireless multiuser communications, but limitations come from the Gaussian approximations used in their derivation. In this Letter, the authors obtain more accurate expressions of the bit error rate (BER for the case when the model of the wide-band channel is two-ray, with Rayleigh fading. In the authors’ approach, the spreading sequences are assumed to be generated by logistic map given by Chebyshev polynomial function of order two. Their theoretical and experimental results show clearly that the previous results on BER, which rely on the crude Gaussian approximation, are over-pessimistic.

  19. GEOM/GEOM[a]/1/ queue with late arrival system with delayed access and delayed multiple working vacations

    Directory of Open Access Journals (Sweden)

    Cheng Jiang

    2014-01-01

    Full Text Available This paper considers a discrete-time bulk-service queue with infinite buffer space and delay multiple working vacations. Considering a late arrival system with delayed access (LAS-AD, it is assumed that the inter-arrival times, service times, vacation times are all geometrically distributed. The server does not take a vacation immediately at service complete epoch but keeps idle period. According to a bulk-service rule, at least one customer is needed to start a service with a maximum serving capacity 'a'. Using probability analysis method and displacement operator method, the queue length and the probability generating function of waiting time at pre-arrival epochs are obtained. Furthermore, the outside observer’s observation epoch queue length distributions are given. Finally, computational examples with numerical results in the form of graphs and tables are discussed.

  20. Turbo code channel reliability for DS/CDMA systems under slow and frequency selective fading and multiple access interference

    Directory of Open Access Journals (Sweden)

    Taufik Abrão

    2008-08-01

    Full Text Available This work analyzes the Turbo and Convolutional codes strategies applied to the single-user detection (SuD problem in multiple access systems DS/CDMA, in multipath slow Rayleigh channels. In this work, a new equation for the DS/CDMA channel reliability, obtained from Monte Carlo Simulations (MCS, is proposed. Comparison with the literature results and has indicated a superior performance in the high Eb/N0 regions; in other Eb/N0 regions the proposed equation has similar performance than those described in the literature. Additionally, this work makes an analysis of the complexity/memory requirements versus performance of DS/CDMA receivers considering turbo (CDMA2000 and Viterbi (IS-95 decoders.

  1. Low-fat, plant-based diet in multiple sclerosis: A randomized controlled trial.

    Science.gov (United States)

    Yadav, Vijayshree; Marracci, Gail; Kim, Edward; Spain, Rebecca; Cameron, Michelle; Overs, Shannon; Riddehough, Andrew; Li, David K B; McDougall, John; Lovera, Jesus; Murchison, Charles; Bourdette, Dennis

    2016-09-01

    The role that dietary interventions can play in multiple sclerosis (MS) management is of huge interest amongst patients and researchers but data evaluating this is limited. Possible effects of a very-low-fat, plant-based dietary intervention on MS related progression and disease activity as measured by brain imaging and MS related symptoms have not been evaluated in a randomized-controlled trial. Despite use of disease modifying therapies (DMT), poor quality of life (QOL) in MS patients can be a significant problem with fatigue being one of the common disabling symptoms. Effective treatment options for fatigue remain limited. Emerging evidence suggests diet and vascular risk factors including obesity and hyperlipidemia may influence MS disease progression and improve QOL. To evaluate adherence, safety and effects of a very-low-fat, plant-based diet (Diet) on brain MRI, clinical [MS relapses and disability, body mass index (BMI)] and metabolic (blood lipids and insulin) outcomes, QOL [Short Form-36 (SF-36)], and fatigue [Fatigue Severity Scale (FSS) and Modified Fatigue Impact Scale (MFIS)], in relapsing-remitting MS (RRMS). This was a randomized-controlled, assessor-blinded, one-year long study with 61 participants assigned to either Diet (N=32) or wait-listed (Control, N=29) group. The mean age (years) [Control-40.9±8.48; Diet-40.8±8.86] and the mean disease duration (years) [Control -5.3±3.86; Diet-5.33±3.63] were comparable between the two groups. There was a slight difference between the two study groups in the baseline mean expanded disability status scale (EDSS) score [Control-2.22±0.90; Diet-2.72±1.05]. Eight subjects withdrew (Diet, N=6; Control, N=2). Adherence to the study diet based on monthly Food Frequency Questionnaire (FFQ) was excellent with the diet group showing significant difference in the total fat caloric intake compared to the control group [total fat intake/total calories averaged ~15% (Diet) versus ~40% (Control)]. The two groups

  2. Quantized conductance in Ta2O5 based resistive random access memory devices

    Science.gov (United States)

    Sahu, V. K.; Misra, P.; Das, A. K.; Ajimsha, R. S.; Singh, B.

    2017-05-01

    We report quantised conductance in Au/Ta2O5/Pt structures grown by pulsed laser deposition. Quantum conduction phenomenon was observed during reset switching event of resistive switching in tantalum oxide (Ta2O5) thin films. Nonvolatile and repeatable electric field controlled unipolar resistive switching was clearly seen in Au/Ta2O5/Pt structures with good endurance. The quantum conduction phenomenon has been attributed to formation of nanometer scale conducting filaments which constraints the motion of electron in transverse direction resulting in quantisation of device conductance in half integer multiple of fundamental unit of conductance G0 (2e2/h). These quantised conductance results in well separated resistance states, suitable for realising futuristic multi-bit resistance switching memory.

  3. Early versus deferred treatment for smoldering multiple myeloma: a meta-analysis of randomized, controlled trials.

    Directory of Open Access Journals (Sweden)

    Minjie Gao

    Full Text Available Whether patients with smoldering multiple myeloma (SMM needed to receive early interventional treatment remains controversial. Herein, we conducted a meta-analysis comparing the efficacy and safety of early treatment over deferred treatment for patients with SMM.MEDLINE and Cochrane Library were searched to May 2014 for randomized controlled trials (RCTs that assessed the effect of early treatment over deferred treatment. Primary outcome measure was mortality, and secondary outcome measures were progression, response rate, and adverse events.Overall, 5 trials including 449 patients were identified. There was a markedly reduced risk of disease progression with early treatment (Odds Ratio [OR] = 0.13, 95% confidence interval [CI] = 0.07 to 0.24. There were no significant differences in mortality and response rate (OR = 0.85, 95% CI = 0.45 to 1.60, and OR = 0.63, 95% CI = 0.32 to 1.23, respectively. More patients in the early treatment arm experienced gastrointestinal toxicities (OR = 10.02, 95%CI = 4.32 to 23.23, constipation (OR = 8.58, 95%CI = 3.20 to 23.00 and fatigue or asthenia (OR = 2.72, 95%CI = 1.30 to 5.67. No significant differences were seen with the development of acute leukemia (OR = 2.80, 95%CI = 0.42 to 18.81, hematologic cancer (OR = 2.07, 95%CI = 0.43 to 10.01, second primary tumors (OR = 3.45, 95%CI = 0.81 to 14.68, nor vertebral compression (OR = 0.18, 95%CI = 0.02 to 1.59.Early treatment delayed disease progression but increased the risk of gastrointestinal toxicities, constipation and fatigue or asthenia. The differences on vertebral compression, acute leukemia, hematological cancer and second primary tumors were not statistically significant. Based on the current evidence, early treatment didn't significantly affect mortality and response rate. However, further much larger trials were needed to provide more evidence.

  4. Integrative group-based cognitive rehabilitation efficacy in multiple sclerosis: a randomized clinical trial.

    Science.gov (United States)

    Rilo, Oiane; Peña, Javier; Ojeda, Natalia; Rodríguez-Antigüedad, Alfredo; Mendibe-Bilbao, Mar; Gómez-Gastiasoro, Ainara; DeLuca, John; Chiaravalloti, Nancy; Ibarretxe-Bilbao, Naroa

    2018-01-01

    This study aimed to determine the efficacy of the integrative group-based cognitive rehabilitation programme, REHACOP, on improving cognitive functions in multiple sclerosis (MS). Fourty-two MS patients were randomized to the treatment programme REHACOP (n = 21) or waiting list control condition (n = 21). The REHACOP group received cognitive rehabilitation in group format for three months focused on attention, processing speed, learning and memory, language, executive functioning, and social cognition. Patients completed a neuropsychological assessment at baseline and follow-up, which included tests of attention, processing speed, working memory, verbal memory, verbal fluency, and executive functioning. Repeated measures multivariate analysis of covariance (MANCOVA) was used to determine the efficacy of the cognitive rehabilitation programme. Group × Time interactions revealed significant improvements in the REHACOP group as compared with the control group for processing speed (p = 0.011, np2 = 0.16), working memory (p = 0.014, np2 = 0.15), verbal memory (p = 0.025, np2 = 0.13), and executive functioning (p = 0.024, np2 = 0.13), showing medium-large effect sizes. Patients receiving REHACOP showed improvements in several cognitive domains. This preliminary study thus provides evidence supporting the efficacy of this integrative group-based cognitive rehabilitation intervention in MS. Future research should confirm these findings, examine the impact of the treatment on everyday life functioning and explore the presence of brain changes associated with cognitive rehabilitation. Implications for rehabilitation This study provides initial evidence for integrative group-based cognitive rehabilitation efficacy in MS patients through the implementation of the REHACOP cognitive rehabilitation programme. Patients received cognitive rehabilitation for three months (3 one-hour-sessions per week) focused on training attention

  5. Early versus deferred treatment for smoldering multiple myeloma: a meta-analysis of randomized, controlled trials.

    Science.gov (United States)

    Gao, Minjie; Yang, Guang; Tompkins, Van S; Gao, Lu; Wu, Xiaosong; Tao, Yi; Hu, Xiaojing; Hou, Jun; Han, Ying; Xu, Hongwei; Zhan, Fenghuang; Shi, Jumei

    2014-01-01

    Whether patients with smoldering multiple myeloma (SMM) needed to receive early interventional treatment remains controversial. Herein, we conducted a meta-analysis comparing the efficacy and safety of early treatment over deferred treatment for patients with SMM. MEDLINE and Cochrane Library were searched to May 2014 for randomized controlled trials (RCTs) that assessed the effect of early treatment over deferred treatment. Primary outcome measure was mortality, and secondary outcome measures were progression, response rate, and adverse events. Overall, 5 trials including 449 patients were identified. There was a markedly reduced risk of disease progression with early treatment (Odds Ratio [OR] = 0.13, 95% confidence interval [CI] = 0.07 to 0.24). There were no significant differences in mortality and response rate (OR = 0.85, 95% CI = 0.45 to 1.60, and OR = 0.63, 95% CI = 0.32 to 1.23, respectively). More patients in the early treatment arm experienced gastrointestinal toxicities (OR = 10.02, 95%CI = 4.32 to 23.23), constipation (OR = 8.58, 95%CI = 3.20 to 23.00) and fatigue or asthenia (OR = 2.72, 95%CI = 1.30 to 5.67). No significant differences were seen with the development of acute leukemia (OR = 2.80, 95%CI = 0.42 to 18.81), hematologic cancer (OR = 2.07, 95%CI = 0.43 to 10.01), second primary tumors (OR = 3.45, 95%CI = 0.81 to 14.68), nor vertebral compression (OR = 0.18, 95%CI = 0.02 to 1.59). Early treatment delayed disease progression but increased the risk of gastrointestinal toxicities, constipation and fatigue or asthenia. The differences on vertebral compression, acute leukemia, hematological cancer and second primary tumors were not statistically significant. Based on the current evidence, early treatment didn't significantly affect mortality and response rate. However, further much larger trials were needed to provide more evidence.

  6. Statistical analysis of the correlations between cell performance and its initial states in contact resistive random access memory cells

    Science.gov (United States)

    Kao, Yun Feng; Hsieh, Wei Ting; Che Chen, Chun; King, Ya-Chin; Lin, Chrong Jung

    2017-04-01

    Variability has been one of the critical challenges in the implementation of large resistive random access memory (RRAM) arrays. Wide variations in set/reset, read and cycling characteristics can significantly reduce the design margin and feasibility of a memory array. Predicting the characteristics of RRAM cells is constructive to provide insights and to adjust the memory operations accordingly. In this study, a strong correlation between the cell performance and its initial state is found in contact RRAM (CRRAM) cells by 28 nm CMOS logic technology. Furthermore, a verify-reset operation is proposed to identify the type of conductive filament (CF) in a cell. Distinctive CRRAM characteristics are found to be linked directly to initial CFs, enabling preliminary screening and adaptive resets to address the large variability problems in sizable CRRAM arrays.

  7. An Agent-Based Fuzzy Collaborative Intelligence Approach for Predicting the Price of a Dynamic Random Access Memory (DRAM Product

    Directory of Open Access Journals (Sweden)

    Toly Chen

    2012-05-01

    Full Text Available Predicting the price of a dynamic random access memory (DRAM product is a critical task to the manufacturer. However, it is not easy to contend with the uncertainty of the price. In order to effectively predict the price of a DRAM product, an agent-based fuzzy collaborative intelligence approach is proposed in this study. In the agent-based fuzzy collaborative intelligence approach, each agent uses a fuzzy neural network to predict the DRAM price based on its view. The agent then communicates its view and forecasting results to other agents with the aid of an automatic collaboration mechanism. According to the experimental results, the overall performance was improved through the agents’ collaboration.

  8. A novel multiplexer-based structure for random access memory cell in quantum-dot cellular automata

    Science.gov (United States)

    Naji Asfestani, Mazaher; Rasouli Heikalabad, Saeed

    2017-09-01

    Quantum-dot cellular automata (QCA) is a new technology in scale of nano and perfect replacement for CMOS circuits in the future. Memory is one of the basic components in any digital system, so designing the random access memory (RAM) with high speed and optimal in QCA is important. In this paper, by employing the structure of multiplexer, a novel RAM cell architecture is proposed. The proposed architecture is implemented without the coplanar crossover approach. The proposed architecture is simulated using the QCADesigner version 2.0.3 and QCAPro. The simulation results demonstrate that the proposed QCA RAM architecture has the best performance in terms of delay, circuit complexity, area, cell count and energy consumption in comparison with other QCA RAM architectures.

  9. Observation of AlO x material in electrical resistive switching for nonvolatile random access memory application

    Science.gov (United States)

    Jung, Kyun-Ho; Song, Seung-Gon; Park, Kyoung-Wan; Sok, Jung-Hyun; Kim, Kyong-Min; Park, Yun-Sun

    2017-03-01

    We fabricated an Al / AlO x / Al device by using a RF magnetron sputter system. The device showed a unipolar resistive switching process. In this study, the switching mechanism of the device followed the conductive filament model. The conduction mechanisms for the conductive filament model were explained by using Ohmic conduction for the low resistance state (LRS) and Schottky emission for the high resistance state (HRS). The average value of the resistance ratio between the HRS and the LRS was about 3.48 × 107 when the reading voltage (0.1 V) was achieved. The electrical property of the endurance was achieved under 50 switching cycles. A low switching voltage could be obtained for a low power consuming device. These results proved that the AlO x material has various possibilities for use in nonvolatile random access memory applications.

  10. Improved characteristics of amorphous indium-gallium-zinc-oxide-based resistive random access memory using hydrogen post-annealing

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Dae Yun; Lee, Tae-Ho; Kim, Tae Geun, E-mail: tgkim1@korea.ac.kr [School of Electrical Engineering, Korea University, Seoul 02841 (Korea, Republic of)

    2016-08-15

    The authors report an improvement in resistive switching (RS) characteristics of amorphous indium-gallium-zinc-oxide (a-IGZO)-based resistive random access memory devices using hydrogen post-annealing. Because this a-IGZO thin film has oxygen off-stoichiometry in the form of deficient and excessive oxygen sites, the film properties can be improved by introducing hydrogen atoms through the annealing process. After hydrogen post-annealing, the device exhibited a stable bipolar RS, low-voltage set and reset operation, long retention (>10{sup 5 }s), good endurance (>10{sup 6} cycles), and a narrow distribution in each current state. The effect of hydrogen post-annealing is also investigated by analyzing the sample surface using X-ray photon spectroscopy and atomic force microscopy.

  11. Effect of barrier layer on switching polarity of ZrO2-based conducting-bridge random access memory

    Science.gov (United States)

    Chandrasekaran, Sridhar; Simanjuntak, Firman Mangasa; Tsai, Tsung-Ling; Lin, Chun-An; Tseng, Tseung-Yuen

    2017-09-01

    In this study, metal diffusion barrier-dependent switching polarity in ZrO2-based conducting-bridge random access memory was investigated. The device without the barrier layer (BL) exhibited nonpolar switching characteristics. However, inserting TiW BL resulted in positive reset failure. This phenomenon depends on the size and shape of the conducting bridge and also on the defects that contribute to the formation and rupture of the bridge. Consequently, the properties of the conducting bridge govern the device switching performance. Cu- and oxygen vacancy-based conducting bridge during N-Set for a device with and without the BL was proposed. The effect of the insertion of BL on the switching performance was also discussed. The absence of BL resulted in switching instability and poor nonvolatility. By contrast, a device with BL exhibited enhanced uniformity and nonvolatility, and the retention was more than 105 s at 200 °C.

  12. Prospective, randomized study of cutting balloon angioplasty versus conventional balloon angioplasty for the treatment of hemodialysis access stenoses.

    Science.gov (United States)

    Saleh, Hossam M; Gabr, Ahmed K; Tawfik, Mohamed M; Abouellail, Hesham

    2014-09-01

    The aim of this trial was to compare the rates of patency achieved by cutting and conventional balloon angioplasty to treat hemodialysis access stenoses. End-stage renal failure patients (at three tertiary referral centers) with significant hemodialysis access stenoses were prospectively randomized to have percutaneous transluminal angioplasty (PTA) by either cutting or conventional balloons. Patients with more than one hemodynamically significant stenosis were excluded. Kaplan-Meier method was used to compare the primary assisted patency rates for the two groups. The study randomized 623 patients into two groups, and the duration of follow-up was 15 ± 3 months. In the cutting balloon angioplasty group, the clinical success rate was 89% (282 of 316 stenoses). In the conventional balloon angioplasty group, the clinical success rate was 86% (265 of 307 stenoses; P = .637). Assisted primary patency for cutting PTA was statistically significantly higher at 6 months and 1 year (86% and 63%) than that for conventional PTA (56% and 37%, respectively; P = .037) in the treatment of stenosis of the graft-to-vein anastomosis. In the venous stenosis subgroup, equivalent primary assisted patency at 6 months and 1 year was observed for cutting PTA (84% and 55%) and conventional PTA (70% and 46%, respectively; P = .360). In the intragraft stenosis subgroup, primary assisted patency was equivalent at 6 months and 1 year for cutting PTA (67% and 39%) and conventional PTA (62% and 49%, respectively; P = .371). In the arterial anastomotic stenosis subgroup, assisted primary patency at 6 months and 1 year was equivalent for cutting PTA (70% and 30%) and conventional PTA (75% and 33%, respectively; P = .921). Cutting balloon angioplasty proved to be a safe and effective treatment of graft-to-vein anastomotic stenosis, with significantly higher patency than that of conventional balloon angioplasty. Copyright © 2014 Society for Vascular Surgery. Published by Mosby, Inc. All rights

  13. Randomized phase 1b trial of MOR103, a human antibody to GM-CSF, in multiple sclerosis

    OpenAIRE

    Constantinescu, Cris S.; Asher, Aliya; Fryze, Waldemar; Kozubski, Wojciech; Wagner, Frank; Aram, Jehan; Tanasescu, Radu; Korolkiewicz, Roman P.; Dirnberger-Hertweck, Maren; Steidl, Stefan; Libretto, Susan E.; Sprenger, Till; Radue, Ernst W.

    2015-01-01

    Objectives: To determine the safety, pharmacokinetics (PK), and immunogenicity of the recombinant human monoclonal antibody MOR103 to granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients with multiple sclerosis (MS) with clinical or MRI activity. Methods: In this 20-week, randomized, double-blind, placebo-controlled phase 1b dose-escalation trial (registration number NCT01517282), adults with relapsing-remitting MS (RRMS) or secondary progressive MS (SPMS) received an IV infu...

  14. Subjective Well-Being and the Family: Results from an Ordered Probit Model with Multiple Random Effects

    OpenAIRE

    Winkelmann, Rainer

    2004-01-01

    The previous literature on the determinants of individual well-being has failed to fully account for the interdependencies in well-being at the family level. This paper develops an ordered probit model with multiple random effects that allows to identify the intrafamily correlation in well-being. The parameters of the model can be estimated with panel data using Maximum Marginal Likelihood. The approach is illustrated in an application using panel data for the period 1984-1997 from the German...

  15. Treatment-enhanced paired action contributes substantially to change across multiple health behaviors: secondary analyses of five randomized trials

    OpenAIRE

    Yin, Hui-Qing; Prochaska, James O.; Rossi, Joseph S.; Redding, Colleen A.; Paiva, Andrea L.; Blissmer, Bryan; Velicer, Wayne F.; Johnson, Sara S.; Kobayashi, Hisanori

    2013-01-01

    The dominant paradigm of changing multiple health behaviors (MHBs) is based on treating, assessing, and studying each behavior separately. This study focused on individuals with co-occurring baseline health-risk behavior pairs and described whether they changed over time on both or only one of the behaviors within each pair. Data from five randomized trials of computer-tailored interventions (CTIs) that simultaneously treated MHBs were analyzed. The differences between treatment and control p...

  16. Comparison of a Ring On-Chip Network and a Code-Division Multiple-Access On-Chip Network

    Directory of Open Access Journals (Sweden)

    Xin Wang

    2007-01-01

    Full Text Available Two network-on-chip (NoC designs are examined and compared in this paper. One design applies a bidirectional ring connection scheme, while the other design applies a code-division multiple-access (CDMA connection scheme. Both of the designs apply globally asynchronous locally synchronous (GALS scheme in order to deal with the issue of transferring data in a multiple-clock-domain environment of an on-chip system. The two NoC designs are compared with each other by their network structures, data transfer principles, network node structures, and their asynchronous designs. Both the synchronous and the asynchronous designs of the two on-chip networks are realized using a hardware-description language (HDL in order to make the entire designs suit the commonly used synchronous design tools and flow. The performance estimation and comparison of the two NoC designs which are based on the HDL realizations are addressed. By comparing the two NoC designs, the advantages and disadvantages of applying direct connection and CDMA connection schemes in an on-chip communication network are discussed.

  17. Hydrogen-dependent low frequency noise and its physical mechanism of HfO2 resistance change random access memory

    Science.gov (United States)

    Chen, Y. Q.; Liu, X.; Liu, Y.; Peng, C.; Fang, W. X.; En, Y. F.; Huang, Y.

    2017-12-01

    The effect of hydrogen on low frequency noise characteristics of HfO2 resistance change random access memories (RRAMs) was investigated in this paper. The experimental results show that HfO2 RRAMs after hydrogen treatment take on the better uniformity of switch characteristics and the conduction enhancement behavior. Furthermore, it was found that the low frequency noise characteristics of the HfO2 RRAMs was significantly impacted by the hydrogen treatment, and at three kinds of typical resistance states, the low frequency noises of the HfO2 RRAMs after hydrogen treatment are larger than those of the fresh HfO2 RRAMs. The mechanism could be attributed to H induced oxygen vacancies, which serve as the additional traps for conduction due to the trap-assisted tunneling process. This will result in more random trap/detrap processes in the conducting filament, which gives rise to the larger low frequency noise in the HfO2 RRAMs. The results of this study may be useful in the design and application of HfO2 RRAMs.

  18. Pharmacological Relaxation of the Ureter When Using Ureteral Access Sheaths during Ureterorenoscopy: A Randomized Feasibility Study in a Porcine Model

    Directory of Open Access Journals (Sweden)

    Søren Kissow Lildal

    2016-01-01

    Full Text Available Objective. High intraluminal pressure during ureterorenoscopy (URS increases risk of infectious and haemorrhagic complications. Intrarenal pressure may be reduced by the use of ureteral access sheaths (UASs, which on the other hand may cause ureteral damage. We have previously shown that the β-agonist isoproterenol (ISO, when administered topically in the irrigation fluid, is able to inhibit ureteral muscle tone and lower intrarenal pressure during URS. The aim of this study was to examine the effect of ISO on the success rate of UAS insertion in a porcine model. Materials and Methods. 22 pigs in which a UAS could not initially be placed were randomized to endoluminal irrigation with either ISO (0.1 μg/mL or saline before a new insertion trial. Subsequently, it was registered whether the UAS could be passed without resistance. During extraction of the sheath, any ureteral lesions were characterized ureteroscopically using the PULS classification system. Surgeons were blinded to randomization. Results. In the ISO group, the observed effect of irrigation was 63% successful UAS insertions, compared to 27% in the saline group. No serious lesions (

  19. Impulsive synchronization of Markovian jumping randomly coupled neural networks with partly unknown transition probabilities via multiple integral approach.

    Science.gov (United States)

    Chandrasekar, A; Rakkiyappan, R; Cao, Jinde

    2015-10-01

    This paper studies the impulsive synchronization of Markovian jumping randomly coupled neural networks with partly unknown transition probabilities via multiple integral approach. The array of neural networks are coupled in a random fashion which is governed by Bernoulli random variable. The aim of this paper is to obtain the synchronization criteria, which is suitable for both exactly known and partly unknown transition probabilities such that the coupled neural network is synchronized with mixed time-delay. The considered impulsive effects can be synchronized at partly unknown transition probabilities. Besides, a multiple integral approach is also proposed to strengthen the Markovian jumping randomly coupled neural networks with partly unknown transition probabilities. By making use of Kronecker product and some useful integral inequalities, a novel Lyapunov-Krasovskii functional was designed for handling the coupled neural network with mixed delay and then impulsive synchronization criteria are solvable in a set of linear matrix inequalities. Finally, numerical examples are presented to illustrate the effectiveness and advantages of the theoretical results. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Speech Recognition Using Randomized Relational Decision Trees

    National Research Council Canada - National Science Library

    Amit, Yali

    1999-01-01

    .... This implies that we recognize words as units, without recognizing their subcomponents. Multiple randomized decision trees are used to access the large pool of acoustic events in a systematic manner and are aggregated to produce the classifier.

  1. Effect of combining multiple micronutrients with iron supplementation on Hb response in children: systematic review of randomized controlled trials.

    Science.gov (United States)

    Gera, Tarun; Sachdev, Harsh Pal Singh; Nestel, Penelope

    2009-06-01

    To study the effect of combining multiple (two or more) micronutrients with Fe supplementation on Hb response, when compared with placebo and with Fe supplementation, in children. Electronic databases, personal files, hand search of reviews, bibliographies of books, and abstracts and proceedings of international conferences. Randomized controlled trials evaluating change in Hb levels with interventions that included Fe and multiple-micronutrient supplementation in comparison to placebo alone or Fe alone were analysed in two systematic reviews. Twenty-five trials were included in the review comparing Fe and micronutrient supplementation with placebo. The pooled estimate (random effects model) for change in Hb with Fe and micronutrient supplementation (weighted mean difference) was 0.65 g/dl (95 % CI 0.50, 0.80, P micronutrients' and malarial non-hyperendemic region were significant predictors of greater Hb response and heterogeneity. Thirteen trials were included in the review comparing Fe and micronutrient supplementation with Fe alone. The pooled estimate for change in Hb with Fe and micronutrient supplementation (weighted mean difference) was 0.14 g/dl (95 % CI 0.00, 0.28, P = 0.04). None of the variables were found to be significant predictors of Hb response. Synthesized evidence indicates that addition of multiple micronutrients to Fe supplementation may only marginally improve Hb response compared with Fe supplementation alone. However, addition of 'other micronutrients' may have a negative effect. Routine addition of unselected multiple micronutrients to Fe therefore appears unjustified for nutritional anaemia control programmes.

  2. Effectiveness of Cognitive Behavioral Therapy on the Quality of Sleep in Women with Multiple Sclerosis: A Randomized Controlled Trial Study

    Directory of Open Access Journals (Sweden)

    Samira Abbasi

    2016-10-01

    Full Text Available Background: Multiple sclerosis is accompanied by secondary clinical signs such as insomnia. Considering the side effects of drugs and also increasing acceptability of psychotherapy methods in health systems, we aimed to determine the effect of group cognitive behavioral therapy on the quality of sleep in women with multiple sclerosis in 2014. Methods: This study is a randomized controlled clinical conducted on 72 women with multiple sclerosis who referred to medical centers of Isfahan. After convenience sampling, participants were randomly allocated into two equal groups of control (n=36 and intervention (n=36. In the intervention group, cognitive behavioral therapy was performed in 8 sessions. The control group, along with receiving the common drugs, participated in 3 group sessions and talked about their feelings and experiences. Data were gathered using Pittsburgh Sleep Quality Index (PSQI and analyzed through independent t-test, Chi-square, Mann Whitney, ANOVA with repeated measure, using SPSS 18. Results: There was a significant difference between the mean score of sleep quality of the control and intervention groups immediately and one month after the intervention (P<0.001. ANOVA with repeated measure test showed that the mean score of sleep quality of patients in the intervention group had a significant difference at three stages of before, immediately and one month after the intervention. Conclusions: According to the results of this study, cognitive behavioral therapy, as an effective and cost-effective therapy, could improve sleep quality in patients with multiple sclerosis.

  3. Effectiveness of Cognitive Behavioral Therapy on the Quality of Sleep in Women with Multiple Sclerosis: A Randomized Controlled Trial Study.

    Science.gov (United States)

    Abbasi, Samira; Alimohammadi, Nasrollah; Pahlavanzadeh, Saeid

    2016-10-01

    Multiple sclerosis is accompanied by secondary clinical signs such as insomnia. Considering the side effects of drugs and also increasing acceptability of psychotherapy methods in health systems, we aimed to determine the effect of group cognitive behavioral therapy on the quality of sleep in women with multiple sclerosis in 2014. This study is a randomized controlled clinical conducted on 72 women with multiple sclerosis who referred to medical centers of Isfahan. After convenience sampling, participants were randomly allocated into two equal groups of control (n=36) and intervention (n=36). In the intervention group, cognitive behavioral therapy was performed in 8 sessions. The control group, along with receiving the common drugs, participated in 3 group sessions and talked about their feelings and experiences. Data were gathered using Pittsburgh Sleep Quality Index (PSQI) and analyzed through independent t-test, Chi-square, Mann Whitney, ANOVA with repeated measure, using SPSS 18. There was a significant difference between the mean score of sleep quality of the control and intervention groups immediately and one month after the intervention (Ptherapy, as an effective and cost-effective therapy, could improve sleep quality in patients with multiple sclerosis. Trial Registration Number: IRCT2015012720833N1.

  4. Internet-based home training is capable to improve balance in multiple sclerosis: a randomized controlled trial.

    Science.gov (United States)

    Frevel, D; Mäurer, M

    2015-02-01

    Balance disorders are common in multiple sclerosis. Aim of the study is to investigate the effectiveness of an Internet-based home training program (e-Training) to improve balance in patients with multiple sclerosis. A randomized, controlled study. Academic teaching hospital in cooperation with the therapeutic riding center Gut Üttingshof, Bad Mergentheim. Eighteen multiple sclerosis patients (mean EDSS 3,5) took part in the trial. Outcome of patients using e-Training (N.=9) was compared to the outcome of patients receiving hippotherapy (N.=9), which can be considered as an advanced concept for the improvement of balance and postural control in multiple sclerosis. After simple random allocation patients received hippotherapy or Internet-based home training (balance, postural control and strength training) twice a week for 12 weeks. Assessments were done before and after the intervention and included static and dynamic balance (primary outcome). Isometric muscle strength of the knee and trunk extension/flexion (dynamometer), walking capacity, fatigue and quality of life served as secondary outcome parameters. Both intervention groups showed comparable and highly significant improvement in static and dynamic balance capacity, no difference was seen between the both intervention groups. However looking at fatigue and quality of life only the group receiving hippotherapy improved significantly. Since e-Training shows even comparable effects to hippotherapy to improve balance, we believe that the established Internet-based home training program, specialized on balance and postural control training, is feasible for a balance and strength training in persons with multiple sclerosis. We demonstrated that Internet-based home training is possible in patients with multiple sclerosis.

  5. Bortezomib consolidation after autologous stem cell transplantation in multiple myeloma: a Nordic Myeloma Study Group randomized phase 3 trial

    Science.gov (United States)

    Gimsing, Peter; Hjertner, Oyvind; Lenhoff, Stig; Laane, Edward; Remes, Kari; Steingrimsdottir, Hlif; Abildgaard, Niels; Ahlberg, Lucia; Blimark, Cecilie; Dahl, Inger Marie; Forsberg, Karin; Gedde-Dahl, Tobias; Gregersen, Henrik; Gruber, Astrid; Guldbrandsen, Nina; Haukås, Einar; Carlson, Kristina; Kvam, Ann Kristin; Nahi, Hareth; Lindås, Roald; Andersen, Niels Frost; Turesson, Ingemar; Waage, Anders; Westin, Jan; Gregersen, Henrik; Frost Andersen, Niels; Gimsing, Peter; Toffner-Clausen, Nilsaage; Abildgaard, Niels; Laane, Edward; Silvennoinen, Raija; Remes, Kari; Steingrimsdottir, Hlif; Lindås, Roald; Gedde-Dahl, Tobias; Guldbrandsen, Nina; Kristin Kvam, Ann; Haukås, Einar; Marie Dahl, Inger; Hjertner, Oyvind; Waage, Anders; Blimark, Cecilie; Mellqvist, Ulf-Henrik; Westin, Jan; Ahlberg, Lucia; Lenhoff, Stig; Turesson, Ingemar; Linder, Olle; Gruber, Astrid; Nahi, Hareth; Forsberg, Karin; Carlson, Kristina

    2013-01-01

    The Nordic Myeloma Study Group conducted an open randomized trial to compare bortezomib as consolidation therapy given after high-dose therapy and autologous stem cell transplantation (ASCT) with no consolidation in bortezomib-naive patients with newly diagnosed multiple myeloma. Overall, 370 patients were centrally randomly assigned 3 months after ASCT to receive 20 doses of bortezomib given during 21 weeks or no consolidation. The hypothesis was that consolidation therapy would prolong progression-free survival (PFS). The PFS after randomization was 27 months for the bortezomib group compared with 20 months for the control group (P = .05). Fifty-one of 90 patients in the treatment group compared with 32 of 90 controls improved their response after randomization (P = .007). No difference in overall survival was seen. Fatigue was reported more commonly by the bortezomib-treated patients in self-reported quality-of-life (QOL) questionnaires, whereas no other major differences in QOL were recorded between the groups. Consolidation therapy seemed to be beneficial for patients not achieving at least a very good partial response (VGPR) but not for patients in the ≥ VGPR category at randomization. Consolidation with bortezomib after ASCT in bortezomib-naive patients improves PFS without interfering with QOL. This trial was registered at www.clinicaltrials.gov as #NCT00417911. PMID:23616624

  6. Mixing stream and datagram traffic on satellite: A FIFO Order-based Demand Assignment (FODA) Time Division Multiple Access (TDMA) scheme

    Science.gov (United States)

    Beltrame, R.; Bonito, A. B.; Celandroni, N.; Ferro, E.

    1985-11-01

    A FIFO Order based Demand Assignment (FODA) access scheme was designed to handle packetized data and voice traffic in a multiple access satellite broadcast channel of Mbits band. The channel is shared by as many as 64 simultaneously active stations in a range of 255 addressable stations. A sophisticated traffic environment is assumed, including different types of service requirements and an arbitrary load distribution among the stations. The results of 2Mbit/sec simulation tests for an existing hardware environment are presented.

  7. Multiple micronutrient supplementation for improving cognitive performance in children: systematic review of randomized controlled trials

    NARCIS (Netherlands)

    Eilander, A.; Gera, T.; Sachdev, H.S.; Transler, C.; Knaap, van der H.; Kok, F.J.; Osendarp, S.J.M.

    2010-01-01

    Background: Although multiple micronutrient interventions have been shown to benefit children's intellectual development, a thorough evaluation of the totality of evidence is currently lacking to direct public health policy. Objective: This study aimed to systematically review the present literature

  8. Simultaneous detection of randomly arranged multiple barcodes using time division multiplexing technique

    Science.gov (United States)

    Haider, Saad Md. Jaglul; Islam, Md. Kafiul

    2010-02-01

    A method of detecting multiple barcodes simultaneously using time division multiplexing technique has been proposed in this paper to minimize the effective time needed for handling multiple tags of barcodes and to lessen the overall workload. Available barcode detection systems can handle multiple types of barcode but a single barcode at a time. This is not so efficient and can create large queue and chaos in places like mega shopping malls or large warehouses where we need to scan huge number of barcodes daily. Our proposed system is expected to improve the real time identification of goods or products on production lines and in automated warehouses or in mega shopping malls in a much more convenient and efficient way. For identifying of multiple barcodes simultaneously, a particular arrangement and orientation of LASER scanner and reflector have been used with a special curve shaped basement where the barcodes are placed. An effective and novel algorithm is developed to extract information from multiple barcodes which introduces starting pattern and ending pattern in barcodes with bit stuffing technique for the convenience of multiple detections. CRC technique is also used for trustworthiness of detection. The overall system enhances the existing single barcode detection system by a great amount although it is easy to implement and use.

  9. High precision three-dimensional iterative indoor localization algorithm using code division multiple access modulation based on visible light communication

    Science.gov (United States)

    Guan, Weipeng; Wu, Yvxiang; Wen, Shangsheng; Yang, Chen; Chen, Hao; Zhang, Zhaoze; Chen, Yingcong

    2016-10-01

    To solve the problem of positioning accuracy affected by mutual interference among multiple reference points in the traditional visible light communication positioning system, an iterative algorithm of received signal strength (RSS) based on code division multiple access (CDMA) coding is proposed. Every light-emitting diode (LED) source broadcasts a unique CDMA modulation identification (ID) code, which is associated with geographic position. The mobile terminal receives a mixed light signal from each LED reference point. By using the orthogonality of the spreading codes, the corresponding ID position information and the intensity attenuation factor of each LED reference point source can be available. According to the ID information and signal attenuation intensity, the location area of each LED and the distance between the receiver end and each LED can be determined. The three-dimensional (3-D) position of the receiver can be obtained by using the iterative algorithm of RSS triangulation. The experimental results show that the proposed algorithm can achieve a positioning accuracy of 5.25 cm in a two-dimensional (2-D) positioning system. And in the 3-D positioning system, the maximum positioning error is 10.27 cm, the minimum positioning error is 0.45 cm, the average positioning error is 3.97 cm, and the proportion of the positioning error exceeding 5 cm is <25%. With a very good positioning accuracy, this system is simple and does not require synchronization processing. What is more, it can be applied to both the 2-D and 3-D localization systems, which has a broad application prospect.

  10. Sampling versus Random Binning for Multiple Descriptions of a Bandlimited Source

    DEFF Research Database (Denmark)

    Mashiach, Adam; Østergaard, Jan; Zamir, Ram

    2013-01-01

    Random binning is an efficient, yet complex, coding technique for the symmetric L-description source coding problem. We propose an alternative approach, that uses the quantized samples of a bandlimited source as "descriptions". By the Nyquist condition, the source can be reconstructed if enough s...

  11. Inhomogeneous Linear Random Differential Equations with Mutual Correlations between Multiplicative, Additive and Initial-Value Terms

    NARCIS (Netherlands)

    Roerdink, J.B.T.M.

    1981-01-01

    The cumulant expansion for linear stochastic differential equations is extended to the general case in which the coefficient matrix, the inhomogeneous part and the initial condition are all random and, moreover, statistically interdependent. The expansion now involves not only the autocorrelation

  12. A randomized trial of motivational interviewing and facilitated contraceptive access to prevent rapid repeat pregnancy among adolescent mothers.

    Science.gov (United States)

    Stevens, Jack; Lutz, Robyn; Osuagwu, Ngozi; Rotz, Dana; Goesling, Brian

    2017-10-01

    Most interventions designed to reduce teen pregnancy rates have not focused on pregnant and/or parenting adolescents. Therefore, a large randomized controlled trial was conducted regarding a motivational interviewing program entitled Teen Options to Prevent Pregnancy in a low-income sample of adolescent mothers. This program recommended monthly sessions between a participant and a registered nurse over 18 months. This program also featured facilitated birth control access through transportation assistance and a part-time contraceptive clinic. The impact of this program on rapid repeat pregnancies at 18 months after enrollment was evaluated. Five hundred ninety-eight adolescent females were enrolled from 7 obstetrics-gynecology clinics and 5 postpartum units of a large hospital system in a Midwestern city. Each participant was enrolled at least 28 weeks pregnant or less than 9 weeks postpartum. Each participant was randomized to either the Teen Options to Prevent Pregnancy intervention or a usual-care control condition. Intervention participants averaged 4.5 hours of assistance. Participants were contacted by blinded research staff at 6 and 18 months to complete self-report surveys. Differences in outcomes between the intervention and control groups were assessed using ordinary least-squares regression. There was an 18.1% absolute reduction in self-reported repeat pregnancy in the intervention group relative to the control group (20.5% vs 38.6%%; P Pregnancy program represents one of the few evidence-based interventions to reduce rapid repeat teen pregnancy. This relatively brief intervention may be a viable alternative to more time-intensive programs that adolescent mothers may be unable or unwilling to receive. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Iterative Fusion of Distributed Decisions over the Gaussian Multiple-Access Channel Using Concatenated BCH-LDGM Codes

    Directory of Open Access Journals (Sweden)

    Crespo PedroM

    2011-01-01

    Full Text Available This paper focuses on the data fusion scenario where nodes sense and transmit the data generated by a source to a common destination, which estimates the original information from more accurately than in the case of a single sensor. This work joins the upsurge of research interest in this topic by addressing the setup where the sensed information is transmitted over a Gaussian Multiple-Access Channel (MAC. We use Low Density Generator Matrix (LDGM codes in order to keep the correlation between the transmitted codewords, which leads to an improved received Signal-to-Noise Ratio (SNR thanks to the constructive signal addition at the receiver front-end. At reception, we propose a joint decoder and estimator that exchanges soft information between the LDGM decoders and a data fusion stage. An error-correcting Bose, Ray-Chaudhuri, Hocquenghem (BCH code is further applied suppress the error floor derived from the ambiguity of the MAC channel when dealing with correlated sources. Simulation results are presented for several values of and diverse LDGM and BCH codes, based on which we conclude that the proposed scheme outperforms significantly (by up to 6.3 dB the suboptimum limit assuming separation between Slepian-Wolf source coding and capacity-achieving channel coding.

  14. Spatial-phase code-division multiple-access system with multiplexed Fourier holography switching for reconfigurable optical interconnection.

    Science.gov (United States)

    Takasago, K; Takekawa, M; Shirakawa, A; Kannari, F

    2000-05-10

    A new, to our knowledge, space-variant optical interconnection system based on a spatial-phase code-division multiple-access technique with multiplexed Fourier holography is described. In this technique a signal beam is spread over wide spatial frequencies by an M-sequence pseudorandom phase code. At a receiver side a selected signal beam is properly decoded, and at the same time its spatial pattern is shaped with a Fourier hologram, which is recorded by light that is encoded with the same M-sequence phase mask as the desired signal beam and by light whose spatial beam pattern is shaped to a signal routing pattern. Using the multiplexed holography, we can simultaneously route multisignal flows into individually specified receiver elements. The routing pattern can also be varied by means of switching the encoding phase code or replacing the hologram. We demonstrated a proof-of-principle experiment with a doubly multiplexed hologram that enables simultaneous routing of two signal beams. Using a numerical model, we showed that the proposed scheme can manage more than 250 routing patterns for one signal flow with one multiplexed hologram at a signal-to-noise ratio of ~5.

  15. Highly reliable switching via phase transition using hydrogen peroxide in homogeneous and multi-layered GaZnO(x)-based resistive random access memory devices.

    Science.gov (United States)

    Park, Sung Pyo; Yoon, Doo Hyun; Tak, Young Jun; Lee, Heesoo; Kim, Hyun Jae

    2015-06-04

    Here, we propose an effective method for improving the resistive switching characteristics of solution-processed gallium-doped zinc oxide (GaZnO(x)) resistive random access memory (RRAM) devices using hydrogen peroxide. Our results imply that solution processed GaZnO(x) RRAM devices could be one of the candidates for the development of low cost RRAM.

  16. Fall risk and incidence reduction in high risk individuals with multiple sclerosis: a pilot randomized control trial.

    Science.gov (United States)

    Sosnoff, Jacob J; Moon, Yaejin; Wajda, Douglas A; Finlayson, Marcia L; McAuley, Edward; Peterson, Elizabeth W; Morrison, Steve; Motl, Robert W

    2015-10-01

    To determine the feasibility of three fall prevention programs delivered over 12 weeks among individuals with multiple sclerosis: (A) a home-based exercise program targeting physiological risk factors; (B) an educational program targeting behavioral risk factors; and (C) a combined exercise-and-education program targeting both factors. Randomized controlled trial. Home-based training with assessments at research laboratory. A total of 103 individuals inquired about the investigation. After screening, 37 individuals with multiple sclerosis who had fallen in the last year and ranged in age from 45-75 years volunteered for the investigation. A total of 34 participants completed postassessment following the 12-week intervention. Participants were randomly assigned into one of four conditions: (1) wait-list control (n = 9); (2) home-based exercise (n = 11); (3) education (n = 9); or (4) a combined exercise and education (n = 8) group. Before and after the 12-week interventions, participants underwent a fall risk assessment as determined by the physiological profile assessment and provided information on their fall prevention behaviors as indexed by the Falls Prevention Strategy Survey. Participants completed falls diaries during the three-months postintervention. A total of 34 participants completed postintervention testing. Procedures and processes were found to be feasible. Overall, fall risk scores were lower in the exercise groups (1.15 SD 1.31) compared with the non-exercise groups (2.04 SD 1.04) following the intervention (p 0.05). Further examination of home-based exercise/education programs for reducing falls in individuals with multiple sclerosis is warranted. A total of 108 participants would be needed in a larger randomized controlled trial.ClinicalTrials.org #NCT01956227. © The Author(s) 2014.

  17. Finding Oxygen Reservoir by Using Extremely Small Test Cell Structure for Resistive Random Access Memory with Replaceable Bottom Electrode.

    Science.gov (United States)

    Kinoshita, Kentaro; Koh, Sang-Gyu; Moriyama, Takumi; Kishida, Satoru

    2015-12-22

    Although the presence of an oxygen reservoir (OR) is assumed in many models that explain resistive switching of resistive random access memory (ReRAM) with electrode/metal oxide (MO)/electrode structures, the location of OR is not clear. We have previously reported a method, which involved the use of an AFM cantilever, for preparing an extremely small ReRAM cell that has a removable bottom electrode (BE). In this study, we used this cell structure to specify the location of OR. Because an anode is often assumed to work as OR, we investigated the effect of changing anodes without changing the MO layer and the cathode on the occurrence of reset. It was found that the reset occurred independently of the catalytic ability and Gibbs free energy (ΔG) of the anode. Our proposed structure enabled to determine that the reset was caused by repairing oxygen vacancies of which a filament consists due to the migration of oxygen ions from the surrounding area when high ΔG anode metal is used, whereas by oxidizing the anode due to the migration of oxygen ions from the MO layer when low ΔG anode metal is used, suggesting the location of OR depends on ΔG of the anode.

  18. Capacitorless one-transistor dynamic random access memory based on double-gate GaAs junctionless transistor

    Science.gov (United States)

    Yoon, Young Jun; Seo, Jae Hwa; Cho, Min Su; Gyeong Kim, Bo; Lee, Sang Hyuk; Kang, In Man

    2017-06-01

    In this paper, we present a capacitorless one-transistor dynamic random access memory (1T-DRAM) based on a double-gate GaAs junctionless transistor (JLT). The proposed 1T-DRAM exhibits an excellent reading operation with a large sensing margin between the “1” and “0” states because the excess hole charges effectively screen the electric field formed by the gate2 voltage (V GS2). In order to reduce the electric field in the drain-gate interface involved in recombination, HfO2 is used as the spacer dielectric. The 1T-DRAM obtains a long retention time of 71 ms due to a low recombination rate. Moreover, we investigate the effect of geometric parameters on DRAM characteristics. The gate length (L G) and body thickness (T body) have a major impact on the sensing margin and retention time. The 1T-DRAM with a long L G and a thin T body can operate with a low power (LP) consumption, a long retention time, and high-density integration.

  19. The role of the local chemical environment of Ag on the resistive switching mechanism of conductive bridging random access memories.

    Science.gov (United States)

    Souchier, E; D'Acapito, F; Noé, P; Blaise, P; Bernard, M; Jousseaume, V

    2015-10-07

    Conductive bridging random access memories (CBRAMs) are one of the most promising emerging technologies for the next generation of non-volatile memory. However, the lack of understanding of the switching mechanism at the nanoscale level prevents successful transfer to industry. In this paper, Ag/GeSx/W CBRAM devices are analyzed using depth selective X-ray Absorption Spectroscopy before and after switching. The study of the local environment around Ag atoms in such devices reveals that Ag is in two very distinct environments with short Ag-S bonds due to Ag dissolved in the GeSx matrix, and longer Ag-Ag bonds related to an Ag metallic phase. These experiments allow the conclusion that the switching process involves the formation of metallic Ag nano-filaments initiated at the Ag electrode. All these experimental features are well supported by ab initio molecular dynamics simulations showing that Ag favorably bonds to S atoms, and permit the proposal of a model at the microscopic level that can explain the instability of the conductive state in these Ag-GeSx CBRAM devices. Finally, the principle of the nondestructive method described here can be extended to other types of resistive memory concepts.

  20. Perpendicular spin transfer torque magnetic random access memories with high spin torque efficiency and thermal stability for embedded applications (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Luc, E-mail: luc.thomas@headway.com; Jan, Guenole; Zhu, Jian; Liu, Huanlong; Lee, Yuan-Jen; Le, Son; Tong, Ru-Ying; Pi, Keyu; Wang, Yu-Jen; Shen, Dongna; He, Renren; Haq, Jesmin; Teng, Jeffrey; Lam, Vinh; Huang, Kenlin; Zhong, Tom; Torng, Terry; Wang, Po-Kang [TDK-Headway Technologies, Inc., Milpitas, California 95035 (United States)

    2014-05-07

    Magnetic random access memories based on the spin transfer torque phenomenon (STT-MRAMs) have become one of the leading candidates for next generation memory applications. Among the many attractive features of this technology are its potential for high speed and endurance, read signal margin, low power consumption, scalability, and non-volatility. In this paper, we discuss our recent results on perpendicular STT-MRAM stack designs that show STT efficiency higher than 5 k{sub B}T/μA, energy barriers higher than 100 k{sub B}T at room temperature for sub-40 nm diameter devices, and tunnel magnetoresistance higher than 150%. We use both single device data and results from 8 Mb array to demonstrate data retention sufficient for automotive applications. Moreover, we also demonstrate for the first time thermal stability up to 400 °C exceeding the requirement of Si CMOS back-end processing, thus opening the realm of non-volatile embedded memory to STT-MRAM technology.

  1. ChIPWig: A Random Access-Enabling Lossless and Lossy Compression Method for ChIP-seq Data.

    Science.gov (United States)

    Ravanmehr, Vida; Kim, Minji; Wang, Zhiying; Milenkovic, Olgica

    2017-10-26

    Chromatin immunoprecipitation sequencing (ChIP-seq) experiments are inexpensive and time-efficient, and result in massive datasets that introduce significant storage and maintenance challenges. To address the resulting Big Data problems, we propose a lossless and lossy compression framework specifically designed for ChIP-seq Wig data, termed ChIPWig. ChIPWig enables random access, summary statistics lookups and it is based on the asymptotic theory of optimal point density design for nonuniform quantizers. We tested the ChIPWig compressor on 10 ChIP-seq datasets generated by the ENCODE consortium. On average, lossless ChIPWig reduced the file sizes to merely 6% of the original, and offered 6-fold compression rate improvement compared to bigWig. The lossy feature further reduced file sizes 2-fold compared to the lossless mode, with little or no effects on peak calling and motif discovery using specialized NarrowPeaks methods. The compression and decompression speed rates are of the order of 0:2 MB/sec using general purpose computers. The source code and binaries are freely available for download athttps://github.com/vidarmehr/ChIPWig-v2, implemented in C ++. milenkov@illinois.edu. Available on the Bioinformatics submission site.

  2. An iterative fullwave simulation approach to multiple scattering in media with randomly distributed microbubbles

    Science.gov (United States)

    Joshi, Aditya; Lindsey, Brooks D.; Dayton, Paul A.; Pinton, Gianmarco; Muller, Marie

    2017-05-01

    Ultrasound contrast agents (UCA), such as microbubbles, enhance the scattering properties of blood, which is otherwise hypoechoic. The multiple scattering interactions of the acoustic field with UCA are poorly understood due to the complexity of the multiple scattering theories and the nonlinear microbubble response. The majority of bubble models describe the behavior of UCA as single, isolated microbubbles suspended in infinite medium. Multiple scattering models such as the independent scattering approximation can approximate phase velocity and attenuation for low scatterer volume fractions. However, all current models and simulation approaches only describe multiple scattering and nonlinear bubble dynamics separately. Here we present an approach that combines two existing models: (1) a full-wave model that describes nonlinear propagation and scattering interactions in a heterogeneous attenuating medium and (2) a Paul-Sarkar model that describes the nonlinear interactions between an acoustic field and microbubbles. These two models were solved numerically and combined with an iterative approach. The convergence of this combined model was explored in silico for 0.5 × 106 microbubbles ml-1, 1% and 2% bubble concentration by volume. The backscattering predicted by our modeling approach was verified experimentally with water tank measurements performed with a 128-element linear array transducer. An excellent agreement in terms of the fundamental and harmonic acoustic fields is shown. Additionally, our model correctly predicts the phase velocity and attenuation measured using through transmission and predicted by the independent scattering approximation.

  3. Sensitivity Analysis of Multiple Informant Models When Data Are Not Missing at Random

    Science.gov (United States)

    Blozis, Shelley A.; Ge, Xiaojia; Xu, Shu; Natsuaki, Misaki N.; Shaw, Daniel S.; Neiderhiser, Jenae M.; Scaramella, Laura V.; Leve, Leslie D.; Reiss, David

    2013-01-01

    Missing data are common in studies that rely on multiple informant data to evaluate relationships among variables for distinguishable individuals clustered within groups. Estimation of structural equation models using raw data allows for incomplete data, and so all groups can be retained for analysis even if only 1 member of a group contributes…

  4. Sum of ratios of products forα-μ random variables in wireless multihop relaying and multiple scattering

    KAUST Repository

    Wang, Kezhi

    2014-09-01

    The sum of ratios of products of independent 2642 2642α-μ random variables (RVs) is approximated by using the Generalized Gamma ratio approximation (GGRA) with Gamma ratio approximation (GRA) as a special case. The proposed approximation is used to calculate the outage probability of the equal gain combining (EGC) or maximum ratio combining (MRC) receivers for wireless multihop relaying or multiple scattering systems considering interferences. Numerical results show that the newly derived approximation works very well verified by the simulation, while GRA has a slightly worse performance than GGRA when outage probability is below 0.1 but with a more simplified form.

  5. Random effects modeling of multiple binomial responses using the multivariate binomial logit-normal distribution.

    Science.gov (United States)

    Coull, B A; Agresti, A

    2000-03-01

    The multivariate binomial logit-normal distribution is a mixture distribution for which, (i) conditional on a set of success probabilities and sample size indices, a vector of counts is independent binomial variates, and (ii) the vector of logits of the parameters has a multivariate normal distribution. We use this distribution to model multivariate binomial-type responses using a vector of random effects. The vector of logits of parameters has a mean that is a linear function of explanatory variables and has an unspecified or partly specified covariance matrix. The model generalizes and provides greater flexibility than the univariate model that uses a normal random effect to account for positive correlations in clustered data. The multivariate model is useful when different elements of the response vector refer to different characteristics, each of which may naturally have its own random effect. It is also useful for repeated binary measurement of a single response when there is a nonexchangeable association structure, such as one often expects with longitudinal data or when negative association exists for at least one pair of responses. We apply the model to an influenza study with repeated responses in which some pairs are negatively associated and to a developmental toxicity study with continuation-ratio logits applied to an ordinal response with clustered observations.

  6. Random Access Nomad Rhetorics.

    Science.gov (United States)

    Eddy, Gary

    Society at present is a sophistic society, a rhetorically negotiated and mediated consensus reality. The 20th century has been a brilliant and bloody transition from "idealism" to the "sophistic." Perhaps the tools of the Sophistic--rhetorical tropes, social construction of meaning, a pragmatic linguistics of consensus making…

  7. Effects of aerobic exercise and yoga on fatigue and general health of patients with multiple sclerosis: a randomized trial

    Directory of Open Access Journals (Sweden)

    Ali Hassanpour Dehkordi

    2016-01-01

    Full Text Available Background: Multiple sclerosis (MS is a common disease of central nervous system (CNS that causes sensorimotor complications through demyelination of CNS neurons. This study was aimed to evaluate the effects of aerobic exercise and yoga on the fatigue and general health of patients with multiple sclerosis. Methods: In this clinical trial, the samples were randomly assigned to three groups of yoga (n: 30, aerobics exercises (n: 30, and control group (n: 30. The data were analyzed by SPSS software using descriptive statistics (mean and standard deviation, ANOVA and independent and pair t-test. Results: The results indicated no significant difference in fatigue and general health among the three groups prior to the study, but after the study, the results showed a significant difference in general health and fatigue in yoga and aerobic exercise groups. Conclusion: Yoga and aerobics exercise decreased the fatigue, promoted the general health, and improved the psychological performance and efficiency of MS patients.

  8. The 3 A's of the access process to long-term care for elderly: providers experiences in a multiple case study in the Netherlands.

    Science.gov (United States)

    Schipper, Lisette; Luijkx, Katrien; Meijboom, Bert; Schols, Jos

    2015-01-01

    The access process is an important step in the care provision to independently living elderly. Still, little attention has been given to the process of access to long-term care for older clients. Access can be described by three dimensions: availability, affordability and acceptability (three A's). In this paper we address the following question: How do care providers take the three dimensions of access into account for the access process to their care and related service provision to independently living elderly? To answer this question we performed a qualitative study. We used data gathered in a multiple case study in the Netherlands. This study provides insight in the way long-term care organizations organize their access process. Not all dimensions were equally present or acknowledged by the case organizations. The dimension acceptability seems an important dimension in the access process, as shown by the efforts done in building a relationship with their clients, mainly through a strong personal relationship between client and care advisor. In that respect it is remarkable that the case organizations do not structurally evaluate their access process. Availability is compromised by practical issues and organizational choices. Affordability hardly seems an issue. Further research can reveal the underlying factors that influence the three A dimensions. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  9. Alzheimer’s disease multiple intervention trial (ADMIT: study protocol for a randomized controlled clinical trial

    Directory of Open Access Journals (Sweden)

    Callahan Christopher M

    2012-06-01

    Full Text Available Abstract Background Given the current lack of disease-modifying therapies, it is important to explore new models of longitudinal care for older adults with dementia that focus on improving quality of life and delaying functional decline. In a previous clinical trial, we demonstrated that collaborative care for Alzheimer’s disease reduces patients’ neuropsychiatric symptoms as well as caregiver stress. However, these improvements in quality of life were not associated with delays in subjects’ functional decline. Trial design Parallel randomized controlled clinical trial with 1:1 allocation. Participants A total of 180 community-dwelling patients aged ≥45 years who are diagnosed with possible or probable Alzheimer’s disease; subjects must also have a caregiver willing to participate in the study and be willing to accept home visits. Subjects and their caregivers are enrolled from the primary care and geriatric medicine practices of an urban public health system serving Indianapolis, Indiana, USA. Interventions All patients receive best practices primary care including collaborative care by a dementia care manager over two years; this best practices primary care program represents the local adaptation and implementation of our prior collaborative care intervention in the urban public health system. Intervention patients also receive in-home occupational therapy delivered in twenty-four sessions over two years in addition to best practices primary care. The focus of the occupational therapy intervention is delaying functional decline and helping both subjects and caregivers adapt to functional impairments. The in-home sessions are tailored to the specific needs and goals of each patient-caregiver dyad; these needs are expected to change over the course of the study. Objective To determine whether best practices primary care plus home-based occupational therapy delays functional decline among patients with Alzheimer’s disease compared

  10. The effects of a group-based cognitive behavioral therapy on people with multiple sclerosis: a randomized controlled trial.

    Science.gov (United States)

    Graziano, Federica; Calandri, Emanuela; Borghi, Martina; Bonino, Silvia

    2014-03-01

    To evaluate the effectiveness of a cognitive behavioral group-based intervention aimed at reducing depression and fostering quality of life and psychological well-being of multiple sclerosis patients through the promotion of identity redefinition, sense of coherence, and self-efficacy. A randomized controlled trial. Non-medical setting, external to the Multiple Sclerosis Clinic Centre. Eighty-two patients: 64% women; mean age 40.5, SD = 9.4; 95% with relapsing-remitting multiple sclerosis; Expanded Disability Status Scale (EDSS) between 1 and 5.5 were included in the study. Patients were randomly assigned to an intervention group (five cognitive behavioral group-based sessions, n = 41) or to a control group (three informative sessions, n = 41). Depression (CES-D), Quality of life (MSQOL revised), Psychological well-being (PANAS), Identity Motives Scale, Sense of Coherence (SOC), and Self Efficacy in Multiple Sclerosis. Quality of life increased in the intervention group compared with the control at 6-months follow-up (mean change 0.72 vs. -1.76, p < 0.05). Well-being in the intervention group increased for males and slightly decreased for females at 6-months follow-up (mean change 6.58 vs. -0.82, p < 0.05). Contrasts revealed an increase in self-efficacy in the intervention group at posttreatment compared with the control (mean change 2.95 vs. -0.11, p < 0.05). Depression tended to lower, while identity and coherence increased in the intervention group compared with the control, though the differences were not significant. Preliminary evidence suggests that intervention promotes patients' quality of life and has an effect on psychological well-being and self-efficacy.

  11. Group exercise training for balance, functional status, spasticity, fatigue and quality of life in multiple sclerosis: a randomized controlled trial.

    Science.gov (United States)

    Tarakci, Ela; Yeldan, Ipek; Huseyinsinoglu, Burcu E; Zenginler, Yonca; Eraksoy, Mefkure

    2013-09-01

    To determine the effectiveness of group exercise training on balance, functional status, spasticity, fatigue and quality of life in patients with multiple sclerosis. A randomized single-blind controlled study. University hospital, outpatient physical therapy department. Ambulatory patients with multiple sclerosis. Exercise group completed a 12-week group exercise programme under the physical therapists' supervision. Control group was included in the waiting list. The primary outcome measures were the Berg Balance Scale, 10-metre walk test, 10-steps climbing test and secondary outcome measures were the Modified Ashworth Scale, Fatigue Severity Scale and Multiple Sclerosis International Quality of Life. Ninety-nine patients completed the study. There were statistically significant improvements for all outcome measures in the group exercise group (n = 51) (p exercise group, while a decreased of 2.33 in control group. The 10-metre walk test duration (second) was decreased 2.72 in exercise group, while increased 1.44 in control group. In comparing inter-groups changes, both primary and secondary outcome mesures showed significant improvements in favour of the exercise group after the training (p exercise training is effective in improving balance, functional status, spasticity, fatigue and quality of life in moderately affected people with multiple sclerosis, with no worsening of their clinical status.

  12. Harmonic functions on multiplicative graphs and inverse Pitman transform on infinite random paths

    OpenAIRE

    Lecouvey, Cédric; Lesigne, Emmanuel; Peigné, Marc

    2014-01-01

    27 pages, minor corrections and a simpler definition of the Pitman inverse.; We introduce and characterize central probability distributions on Littelmann paths. Next we establish a law of large numbers and a central limit theorem for the generalized Pitmann transform. We then study harmonic functions on multiplicative graphs defined from the tensor powers of finite-dimensional Lie algebras representations. Finally, we show there exists an inverse of the generalized Pitman transform defined a...

  13. [Physiotherapy and neurogenic lower urinary tract dysfunction in multiple sclerosis patients: a randomized controlled trial].

    Science.gov (United States)

    Gaspard, L; Tombal, B; Opsomer, R-J; Castille, Y; Van Pesch, V; Detrembleur, C

    2014-09-01

    This randomized controlled trial compare the efficacy of pelvic floor muscle training vs. transcutaneous posterior tibial nerve stimulation. Inclusion criteria were EDSS scorepregnancy. The primary outcome was quality of life (SF-Qualiveen questionnaire). Secondary outcomes included overactive bladder (USP questionnaire) score and frequency of urgency episodes (3-day bladder diary). Sample size was calculated after 18 patients were included. Data analysis was blinded. Each patient received 9 sessions of 30 minutes weekly. Patients were randomized in pelvic floor muscles exercises with biofeedback group (muscle endurance and relaxation) or transcutaneous posterior tibial nerve stimulation group (rectangular alternative biphasic current with low frequency). A total of 31 patients were included. No difference appeared between groups for quality of life, overactive bladder and frequency of urgency episodes (respectively P=0.197, P=0.532 et P=0.788). These parameters were significantly improved in pelvic floor muscle training group (n=16) (respectively P=0.004, P=0.002 et P=0.006) and in transcutaneous posterior tibial nerve stimulation group (n=15) (respectively P=0.001, P=0.001 et P=0.031). Pelvic floor muscle training and transcutaneous posterior tibial nerve stimulation improved in the same way symptoms related to urgency in MS patients with mild disability. 2. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  14. Azathioprine versus Beta Interferons for Relapsing-Remitting Multiple Sclerosis: A Multicentre Randomized Non-Inferiority Trial

    Science.gov (United States)

    Massacesi, Luca; Tramacere, Irene; Amoroso, Salvatore; Battaglia, Mario A.; Benedetti, Maria Donata; Filippini, Graziella; La Mantia, Loredana; Repice, Anna; Solari, Alessandra; Tedeschi, Gioacchino; Milanese, Clara

    2014-01-01

    For almost three decades in many countries azathioprine has been used to treat relapsing-remitting multiple sclerosis. However its efficacy was usually considered marginal and following approval of β interferons for this indication it was no longer recommended as first line treatment, even if presently no conclusive direct β interferon-azathioprine comparison exists. To compare azathioprine efficacy versus the currently available β interferons in relapsing-remitting multiple sclerosis, a multicenter, randomized, controlled, single-blinded, non-inferiority trial was conducted in 30 Italian multiple sclerosis centers. Eligible patients (relapsing-remitting course; ≥2 relapses in the last 2 years) were randomly assigned to azathioprine or β interferons. The primary outcome was annualized relapse rate ratio (RR) over 2 years. Key secondary outcome was number of new brain MRI lesions. Patients (n = 150) were randomized in 2 groups (77 azathioprine, 73 β interferons). At 2 years, clinical evaluation was completed in 127 patients (62 azathioprine, 65 β interferons). Annualized relapse rate was 0.26 (95% Confidence Interval, CI, 0.19–0.37) in the azathioprine and 0.39 (95% CI 0.30–0.51) in the interferon group. Non-inferiority analysis showed that azathioprine was at least as effective as β interferons (relapse RRAZA/IFN 0.67, one-sided 95% CI 0.96; p<0.01). MRI outcomes were analyzed in 97 patients (50 azathioprine and 47 β interferons). Annualized new T2 lesion rate was 0.76 (95% CI 0.61–0.95) in the azathioprine and 0.69 (95% CI 0.54–0.88) in the interferon group. Treatment discontinuations due to adverse events were higher (20.3% vs. 7.8%, p = 0.03) in the azathioprine than in the interferon group, and concentrated within the first months of treatment, whereas in the interferon group discontinuations occurred mainly during the second year. The results of this study indicate that efficacy of azathioprine is not inferior to that of

  15. Thalidomide versus dexamethasone for the treatment of relapsed and/or refractory multiple myeloma: results from OPTIMUM, a randomized trial

    Science.gov (United States)

    Kropff, Martin; Baylon, Honorata Giongco; Hillengass, Jens; Robak, Tadeusz; Hajek, Roman; Liebisch, Peter; Goranov, Stefan; Hulin, Cyrille; Bladé, Joan; Caravita, Tommaso; Avet-Loiseau, Herve; Moehler, Thomas M.; Pattou, Claire; Lucy, Lela; Kueenburg, Elisabeth; Glasmacher, Axel; Zerbib, Robert; Facon, Thierry

    2012-01-01

    Background Thalidomide has potent antimyeloma activity, but no prospective, randomized controlled trial has evaluated thalidomide monotherapy in patients with relapsed/refractory multiple myeloma. Design and Methods We conducted an international, randomized, open-label, four-arm, phase III trial to compare three different doses of thalidomide (100, 200, or 400 mg/day) with standard dexamethasone in patients who had received one to three prior therapies. The primary end-point was time to progression. Results In the intent-to-treat population (N=499), the median time to progression was 6.1, 7.0, 7.6, and 9.1 months in patients treated with dexamethasone, and thalidomide 100, 200, and 400 mg/day, respectively; the difference between treatment groups was not statistically significant. In the per-protocol population (n=465), the median time to progression was 6.0, 7.0, 8.0, and 9.1 months, respectively. In patients who had received two or three prior therapies, thalidomide significantly prolonged the time to progression at all dose levels compared to the result achieved with dexamethasone. Response rates and median survival were similar in all treatment groups, but the median duration of response was significantly longer in all thalidomide groups than in the dexamethasone group. Adverse events reported in the thalidomide groups, such as fatigue, constipation and neuropathy, confirmed the known safety profile of thalidomide. Conclusions Although thalidomide was not superior to dexamethasone in this randomized trial, thalidomide monotherapy may be considered an effective salvage therapy option for patients with relapsed/refractory multiple myeloma, particularly those with a good prognosis and those who have received two or three prior therapies. The recommended starting dose of thalidomide monotherapy is 400 mg/day, which can be rapidly reduced for patients who do not tolerate this treatment. (Clinical trial registration number: NCT00452569) PMID:22133776

  16. Pilates exercise training vs. physical therapy for improving walking and balance in people with multiple sclerosis: a randomized controlled trial.

    Science.gov (United States)

    Kalron, Alon; Rosenblum, Uri; Frid, Lior; Achiron, Anat

    2017-03-01

    Evaluate the effects of a Pilates exercise programme on walking and balance in people with multiple sclerosis and compare this exercise approach to conventional physical therapy sessions. Randomized controlled trial. Multiple Sclerosis Center, Sheba Medical Center, Tel-Hashomer, Israel. Forty-five people with multiple sclerosis, 29 females, mean age (SD) was 43.2 (11.6) years; mean Expanded Disability Status Scale (S.D) was 4.3 (1.3). Participants received 12 weekly training sessions of either Pilates ( n=22) or standardized physical therapy ( n=23) in an outpatient basis. Spatio-temporal parameters of walking and posturography parameters during static stance. Functional tests included the Time Up and Go Test, 2 and 6-minute walk test, Functional Reach Test, Berg Balance Scale and the Four Square Step Test. In addition, the following self-report forms included the Multiple Sclerosis Walking Scale and Modified Fatigue Impact Scale. At the termination, both groups had significantly increased their walking speed ( P=0.021) and mean step length ( P=0.023). According to the 2-minute and 6-minute walking tests, both groups at the end of the intervention program had increased their walking speed. Mean (SD) increase in the Pilates and physical therapy groups were 39.1 (78.3) and 25.3 (67.2) meters, respectively. There was no effect of group X time in all instrumented and clinical balance and gait measures. Pilates is a possible treatment option for people with multiple sclerosis in order to improve their walking and balance capabilities. However, this approach does not have any significant advantage over standardized physical therapy.

  17. Methods for synthesizing findings on moderation effects across multiple randomized trials.

    Science.gov (United States)

    Brown, C Hendricks; Sloboda, Zili; Faggiano, Fabrizio; Teasdale, Brent; Keller, Ferdinand; Burkhart, Gregor; Vigna-Taglianti, Federica; Howe, George; Masyn, Katherine; Wang, Wei; Muthén, Bengt; Stephens, Peggy; Grey, Scott; Perrino, Tatiana

    2013-04-01

    This paper presents new methods for synthesizing results from subgroup and moderation analyses across different randomized trials. We demonstrate that such a synthesis generally results in additional power to detect significant moderation findings above what one would find in a single trial. Three general methods for conducting synthesis analyses are discussed, with two methods, integrative data analysis and parallel analyses, sharing a large advantage over traditional methods available in meta-analysis. We present a broad class of analytic models to examine moderation effects across trials that can be used to assess their overall effect and explain sources of heterogeneity, and present ways to disentangle differences across trials due to individual differences, contextual level differences, intervention, and trial design.

  18. A randomized trial of teriflunomide added to glatiramer acetate in relapsing multiple sclerosis.

    Science.gov (United States)

    Freedman, M S; Wolinsky, J S; Truffinet, P; Comi, G; Kappos, L; Miller, A E; Olsson, T P; Benamor, M; Chambers, S; O'Connor, P W

    2015-01-01

    Teriflunomide is a once-daily oral immunomodulator for the treatment of relapsing-remitting MS. To evaluate the safety and tolerability of teriflunomide as add-on therapy to a stable dose of glatiramer acetate (GA) in patients with relapsing forms of MS (RMS). Phase II, randomized, double-blind, add-on, placebo-controlled study. The primary objective was to assess safety and tolerability; secondary objectives were to evaluate effects of treatment on disease activity assessed by MRI and relapse. Patients with RMS on GA (N = 123) were randomized 1:1:1 to receive teriflunomide 14 mg (n = 40), 7 mg (n = 42), or placebo (n = 41) for 24 weeks; 96 patients entered the 24-week extension, remaining on original treatment allocation. Teriflunomide was well tolerated over 48 weeks. The frequency of adverse events (AEs) was low across all groups; 5 (12.2%), 3 (7.1%), and 2 (5.0%) patients in the 14 mg, 7 mg, and placebo groups, respectively, discontinued treatment due to AEs. Teriflunomide reduced the number of T1-Gd lesions vs placebo (14 mg: 46.6% relative reduction, p = 0.1931; 7 mg: 64.0%: relative reduction, p = 0.0306). Teriflunomide added to stable-dose GA had acceptable safety and tolerability, and reduced some MRI markers of disease activity compared with GA alone. NCT00475865 (core study); NCT00811395 (extension).

  19. Efficacy of Vitamin D Supplementation in Multiple Sclerosis (EVIDIMS Trial: study protocol for a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Dörr Jan

    2012-02-01

    Full Text Available Abstract Background Multiple sclerosis is the most common chronic inflammatory disease of the central nervous system in young adults. Despite the fact that numerous lines of evidence link both the risk of disease development and the disease course to the serum level of 25-hydroxyvitamin D it still remains elusive whether multiple sclerosis patients benefit from boosting the serum level of 25-hydroxyvitamin D, mainly because interventional clinical trials that directly address the therapeutic effects of vitamin D in multiple sclerosis are sparse. We here present the protocol of an interventional clinical phase II study to test the hypothesis, that high-dose vitamin D supplementation of multiple sclerosis patients is safe and superior to low-dose supplementation with respect to beneficial therapeutic effects. Methods/Design The EVIDIMS trial is a German multi-center, stratified, randomized, controlled and double-blind clinical phase II pilot study. Eighty patients with the diagnosis of definite multiple sclerosis or clinically isolated syndrome who are on a stable immunomodulatory treatment with interferon-β1b will be randomized to additionally receive either high-dose (average daily dose 10.200 IU or low-dose (average daily dose 200 IU cholecalciferol for a total period of 18 months. The primary outcome measure is the number of new lesions detected on T2-weighted cranial MRI at 3 tesla. Secondary endpoints include additional magnetic resonance imaging and optical coherence tomography parameters for neuroinflammation and -degeneration, clinical parameters for disease activity, as well as cognition, fatigue, depression, and quality of life. Safety and tolerability of high-dose vitamin D supplementation are further outcome parameters. Discussion In light of the discrepancy between existing epidemiological and preclinical data on the one hand and available clinical data on the other the EVIDIMS trial will substantially contribute to the evaluation

  20. Acute effects of single and multiple level thoracic manipulations on chronic mechanical neck pain: a randomized controlled trial

    Science.gov (United States)

    Puntumetakul, Rungthip; Suvarnnato, Thavatchai; Werasirirat, Phurichaya; Uthaikhup, Sureeporn; Yamauchi, Junichiro; Boucaut, Rose

    2015-01-01

    Background Thoracic spine manipulation has become a popular alternative to local cervical manipulative therapy for mechanical neck pain. This study investigated the acute effects of single-level and multiple-level thoracic manipulations on chronic mechanical neck pain (CMNP). Methods Forty-eight patients with CMNP were randomly allocated to single-level thoracic manipulation (STM) at T6–T7 or multiple-level thoracic manipulation (MTM), or to a control group (prone lying). Cervical range of motion (CROM), visual analog scale (VAS), and the Thai version of the Neck Disability Index (NDI-TH) scores were measured at baseline, and at 24-hour and at 1-week follow-up. Results At 24-hour and 1-week follow-up, neck disability and pain levels were significantly (Pneck disability, pain level at rest, and CROM between the STM and MTM groups. Conclusion These results suggest that both single-level and multiple-level thoracic manipulation improve neck disability, pain levels, and CROM at 24-hour and 1-week follow-up in patients with CMNP. PMID:25624764

  1. Protocol for the saMS trial (supportive adjustment for multiple sclerosis: a randomized controlled trial comparing cognitive behavioral therapy to supportive listening for adjustment to multiple sclerosis

    Directory of Open Access Journals (Sweden)

    McCrone Paul

    2009-08-01

    Full Text Available Abstract Background Multiple Sclerosis (MS is an incurable, chronic, potentially progressive and unpredictable disease of the central nervous system. The disease produces a range of unpleasant and debilitating symptoms, which can have a profound impact including disrupting activities of daily living, employment, income, relationships, social and leisure activities, and life goals. Adjusting to the illness is therefore particularly challenging. This trial tests the effectiveness of a Cognitive Behavioural intervention compared to Supportive Listening to assist adjustment in the early stages of MS. Methods/Design This is a two arm randomized multi-centre parallel group controlled trial. 122 consenting participants who meet eligibility criteria will be randomly allocated to receive either Cognitive Behavioral Therapy or Supportive Listening. Eight one hour sessions of therapy (delivered over a period of 10 weeks will be delivered by general nurses trained in both treatments. Self-report questionnaire data will be collected at baseline (0 weeks, mid-therapy (week 5 of therapy, post-therapy (15 weeks and at six months (26 weeks and twelve months (52 weeks follow-up. Primary outcomes are distress and MS-related social and role impairment at twelve month follow-up. Analysis will also consider predictors and mechanisms of change during therapy. In-depth interviews to examine participants' experiences of the interventions will be conducted with a purposively sampled sub-set of the trial participants. An economic analysis will also take place. Discussion This trial is distinctive in its aims in that it aids adjustment to MS in a broad sense. It is not a treatment specifically for depression. Use of nurses as therapists makes the interventions potentially viable in terms of being rolled out in the NHS. The trial benefits from incorporating patient input in the development and evaluation stages. The trial will provide important information about the

  2. Metabolic response to epigallocatechin-3-gallate in relapsing-remitting multiple sclerosis: a randomized clinical trial.

    Science.gov (United States)

    Mähler, Anja; Steiniger, Jochen; Bock, Markus; Klug, Lars; Parreidt, Nadine; Lorenz, Mario; Zimmermann, Benno F; Krannich, Alexander; Paul, Friedemann; Boschmann, Michael

    2015-03-01

    Muscle weakness and fatigue are common symptoms in multiple sclerosis (MS). Green tea catechins such as (-)epigallocatechin-3-gallate (EGCG) are known to improve energy metabolism at rest and during exercise. We tested the hypothesis that EGCG improves energy metabolism and substrate utilization in patients with MS. Eighteen patients (8 men) with relapsing-remitting MS (expanded disability status scale score women). After placebo, exercise EE was mainly fueled by FAOx in both men and women. After EGCG, there was a shift to a higher and more stable CHOx during exercise in men but not in women. Our data indicate that EGCG given to patients with MS over 12 wk improves muscle metabolism during moderate exercise to a greater extent in men than in women, possibly because of sex-specific effects on autonomic and endocrine control. © 2015 American Society for Nutrition.

  3. Critical side channel effects in random bit generation with multiple semiconductor lasers in a polarization-based quantum key distribution system.

    Science.gov (United States)

    Ko, Heasin; Choi, Byung-Seok; Choe, Joong-Seon; Kim, Kap-Joong; Kim, Jong-Hoi; Youn, Chun Ju

    2017-08-21

    Most polarization-based BB84 quantum key distribution (QKD) systems utilize multiple lasers to generate one of four polarization quantum states randomly. However, random bit generation with multiple lasers can potentially open critical side channels that significantly endangers the security of QKD systems. In this paper, we show unnoticed side channels of temporal disparity and intensity fluctuation, which possibly exist in the operation of multiple semiconductor laser diodes. Experimental results show that the side channels can enormously degrade security performance of QKD systems. An important system issue for the improvement of quantum bit error rate (QBER) related with laser driving condition is further addressed with experimental results.

  4. A multicenter randomized crossover multiple-dose comparison study of arotinolol and propranolol in essential tremor.

    Science.gov (United States)

    Lee, Kwang-Soo; Kim, Joong-Seok; Kim, Jae-Woo; Lee, Won-Yong; Jeon, Beum-Seok; Kim, Dongjae

    2003-08-01

    A new medication is needed to treat essential tremor. Preliminary evidence suggests that arotinolol may be effective in the treatment of this disorder. To study the effect of arotinolol and propranolol in a crossover, multiple dose comparative trial of patients with essential tremor. One hundred and seventy-five outpatients, with essential tremor were included in the study; 161 patients completed the study. Patients were identically evaluated at eight consecutive visits. The study consisted of two treatments, which were arranged according to a crossover design that evaluated the dose of each (arotinolol 10 mg per day and propranolol 40 mg per day, arotinolol 20 mg per day and propranolol 80 mg per day, arotinolol 30 mg per day and propranolol 160 mg per day). Each course of treatment lasted 6 weeks. Major outcome evaluations consisted of a self-reported disability scale, and motor performance score obtained before drug intake and 14 days after each treatment. The treatment effects were evaluated by analysis of variance using the Hills-Armitage test. Arotinolol was found to be as effective as propranolol at reducing tremor. Drug effects as evaluated using motor-task performance scores revealed that arotinolol had a more significant effect than propranolol. Arotinolol may be more useful than propranolol for the treatment of essential tremor.

  5. Communication interventions for minimally verbal children with autism: a sequential multiple assignment randomized trial.

    Science.gov (United States)

    Kasari, Connie; Kaiser, Ann; Goods, Kelly; Nietfeld, Jennifer; Mathy, Pamela; Landa, Rebecca; Murphy, Susan; Almirall, Daniel

    2014-06-01

    This study tested the effect of beginning treatment with a speech-generating device (SGD) in the context of a blended, adaptive treatment design for improving spontaneous, communicative utterances in school-aged, minimally verbal children with autism. A total of 61 minimally verbal children with autism, aged 5 to 8 years, were randomized to a blended developmental/behavioral intervention (JASP+EMT) with or without the augmentation of a SGD for 6 months with a 3-month follow-up. The intervention consisted of 2 stages. In stage 1, all children received 2 sessions per week for 3 months. Stage 2 intervention was adapted (by increased sessions or adding the SGD) based on the child's early response. The primary outcome was the total number of spontaneous communicative utterances; secondary measures were the total number of novel words and total comments from a natural language sample. Primary aim results found improvements in spontaneous communicative utterances, novel words, and comments that all favored the blended behavioral intervention that began by including an SGD (JASP+EMT+SGD) as opposed to spoken words alone (JASP+EMT). Secondary aim results suggest that the adaptive intervention beginning with JASP+EMT+SGD and intensifying JASP+EMT+SGD for children who were slow responders led to better posttreatment outcomes. Minimally verbal school-aged children can make significant and rapid gains in spoken spontaneous language with a novel, blended intervention that focuses on joint engagement and play skills and incorporates an SGD. Future studies should further explore the tailoring design used in this study to better understand children's response to treatment. Clinical trial registration information-Developmental and Augmented Intervention for Facilitating Expressive Language (CCNIA); http://clinicaltrials.gov/; NCT01013545. Copyright © 2014 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

  6. Communication Interventions for Minimally Verbal Children With Autism: Sequential Multiple Assignment Randomized Trial

    Science.gov (United States)

    Kasari, Connie; Kaiser, Ann; Goods, Kelly; Nietfeld, Jennifer; Mathy, Pamela; Landa, Rebecca; Murphy, Susan; Almirall, Daniel

    2014-01-01

    Objective This study tested the effect of beginning treatment with a speech-generating device in the context of a blended, adaptive treatment design for improving spontaneous, communicative utterances in school-aged, minimally verbal children with autism. Method Sixty-one minimally verbal children with autism, aged 5 to 8 years, were randomized to a blended developmental/behavioral intervention (JASP+EMT) with or without the augmentation of a speech-generating device (SGD) for 6 months with a 3-month follow-up. The intervention consisted of two stages. In Stage 1 all children received two sessions per week for 3 months. Stage 2 intervention was adapted (increased sessions or adding the SGD) based on the child’s early response. The primary outcome was the total number of spontaneous communicative utterances; secondary measures were total number of novel words and total comments from a natural language sample. Results Primary aim results found improvements in spontaneous communicative utterances, novel words, and comments that all favored the blended behavioral intervention that began by including an SGD (JASP+EMT+SGD) as opposed to spoken words alone (JASP+EMT). Secondary aim results suggest that the adaptive intervention beginning with JASP+EMT+SGD and intensifying JASP+EMT+SGD for children who were slow responders led to better post-treatment outcomes. Conclusion Minimally verbal school-aged children can make significant and rapid gains in spoken spontaneous language with a novel, blended intervention that focuses on joint engagement and play skills and incorporates an SGD. Future studies should further explore the tailoring design used in this study to better understand children’s response to treatment. Clinical trial registration information—Developmental and Augmented Intervention for Facilitating Expressive Language (CCNIA); http://clinicaltrials.gov/; NCT01013545. PMID:24839882

  7. A Novel Randomized Search Technique for Multiple Mobile Robot Paths Planning In Repetitive Dynamic Environment

    Directory of Open Access Journals (Sweden)

    Vahid Behravesh

    2012-08-01

    Full Text Available Presented article is studying the issue of path navigating for numerous robots. Our presented approach is based on both priority and the robust method for path finding in repetitive dynamic. Presented model can be generally implementable and useable: We do not assume any restriction regarding the quantity of levels of freedom for robots, and robots of diverse kinds can be applied at the same time. We proposed a random method and hill-climbing technique in the area based on precedence plans, which is used to determine a solution to a given trajectory planning problem and to make less the extent of total track. Our method plans trajectories for particular robots in the setting-time scope. Therefore, in order to specifying the interval of constant objects similar to other robots and the extent of the tracks which is traversed. For measuring the hazard for robots to conflict with each other it applied a method based on probability of the movements of robots. This algorithm applied to real robots with successful results. The proposed method performed and judged on both real robots and in simulation. We performed sequence of100tests with 8 robots for comparing with coordination method and current performances are effective. However, maximizing the performance is still possible. These performances estimations performed on Windows operating system and 3GHz Intel Pentium IV with and compiles with GCC 3.4. We used our PCGA robot for all experiments.  For a large environment of 19×15m2where we accomplished 40tests, our model is competent to plan high-quality paths in a severely short time (less than a second. Moreover, this article utilized lookup tables to keep expenses the formerly navigated robots made, increasing the number of robots don’t expand computation time.

  8. A Parallel Biased Random-Key Genetic Algorithm with Multiple Populations Applied to Irregular Strip Packing Problems

    Directory of Open Access Journals (Sweden)

    Bonfim Amaro Júnior

    2017-01-01

    Full Text Available The irregular strip packing problem (ISPP is a class of cutting and packing problem (C&P in which a set of items with arbitrary formats must be placed in a container with a variable length. The aim of this work is to minimize the area needed to accommodate the given demand. ISPP is present in various types of industries from manufacturers to exporters (e.g., shipbuilding, clothes, and glass. In this paper, we propose a parallel Biased Random-Key Genetic Algorithm (µ-BRKGA with multiple populations for the ISPP by applying a collision-free region (CFR concept as the positioning method, in order to obtain an efficient and fast layout solution. The layout problem for the proposed algorithm is represented by the placement order into the container and the corresponding orientation. In order to evaluate the proposed (µ-BRKGA algorithm, computational tests using benchmark problems were applied, analyzed, and compared with different approaches.

  9. Computed tomography synthesis from magnetic resonance images in the pelvis using multiple random forests and auto-context features

    DEFF Research Database (Denmark)

    Andreasen, Daniel; Morgenthaler Edmund, Jens; Zografos, Vasileios

    2016-01-01

    In radiotherapy treatment planning that is only based on magnetic resonance imaging (MRI), the electron density information usually obtained from computed tomography (CT) must be derived from the MRI by synthesizing a so-called pseudo CT (pCT). This is a non-trivial task since MRI intensities...... are neither uniquely nor quantitatively related to electron density. Typical approaches involve either a classification or regression model requiring specialized MRI sequences to solve intensity ambiguities, or an atlas-based model necessitating multiple registrations between atlases and subject scans....... In this work, we explore a machine learning approach for creating a pCT of the pelvic region from conventional MRI sequences without using atlases. We use a random forest provided with information about local texture, edges and spatial features derived from the MRI. This helps to solve intensity ambiguities...

  10. A group-delivered self-management program reduces spasticity in people with multiple sclerosis: A randomized, controlled pilot trial.

    Science.gov (United States)

    Hugos, Cinda L; Bourdette, Dennis; Chen, Yiyi; Chen, Zunqiu; Cameron, Michelle

    2017-01-01

    Spasticity affects more than 80% of people with multiple sclerosis (MS), affecting activity, participation, and quality of life. Based on an international guideline, an MS spasticity group education and stretching program, MS Spasticity: Take Control (STC), has been developed. The objective of this paper is to determine whether STC with home stretching is associated with greater changes in spasticity than usual care (UC), consisting of an illustrated stretching booklet and home stretching but without group instruction or support, in people with MS. Ambulatory MS patients with self-reported spasticity interfering with daily activities were randomized to STC or UC. Individuals completed questionnaires regarding MS, spasticity, walking, fatigue and mood, and physical measures of spasticity and walking. Thirty-eight of 40 participants completed both assessments. Mean total score and scores on two subscales of the MS Spasticity Scale-88 improved more with STC than with UC (p spasticity more than UC and provided encouraging improvements in other measures.

  11. A Mechanistic Analysis of Oxygen Vacancy Driven Conductive Filament Formation in Resistive Random Access Memory Metal/NiO/Metal Structures (Preprint)

    Science.gov (United States)

    2018-01-10

    metal -induced gap states to the electronic density of states were identified, accommodating oxygen vacancy states, and showing that the interface region...Electrically switchable resistive random access memories have drawn much interest as nonvolatile memory device candidates, based also metal -insulator... metal (MIM) structure concepts. However, atomic-level mechanisms that lead to conductive filament (CF) formation in MIMs are often lacking, such as

  12. Effects of correlations and fees in random multiplicative environments: Implications for portfolio management

    Science.gov (United States)

    Alper, Ofer; Somekh-Baruch, Anelia; Pirvandy, Oz; Schaps, Malka; Yaari, Gur

    2017-08-01

    Geometric Brownian motion (GBM) is frequently used to model price dynamics of financial assets, and a weighted average of multiple GBMs is commonly used to model a financial portfolio. Diversified portfolios can lead to an increased exponential growth compared to a single asset by effectively reducing the effective noise. The sum of GBM processes is no longer a log-normal process and has a complex statistical properties. The nonergodicity of the weighted average process results in constant degradation of the exponential growth from the ensemble average toward the time average. One way to stay closer to the ensemble average is to maintain a balanced portfolio: keep the relative weights of the different assets constant over time. To keep these proportions constant, whenever assets values change, it is necessary to rebalance their relative weights, exposing this strategy to fees (transaction costs). Two strategies that were suggested in the past for cases that involve fees are rebalance the portfolio periodically and rebalance it in a partial way. In this paper, we study these two strategies in the presence of correlations and fees. We show that using periodic and partial rebalance strategies, it is possible to maintain a steady exponential growth while minimizing the losses due to fees. We also demonstrate how these redistribution strategies perform in a phenomenal way on real-world market data, despite the fact that not all assumptions of the model hold in these real-world systems. Our results have important implications for stochastic dynamics in general and to portfolio management in particular, as we show that there is a superior alternative to the common buy-and-hold strategy, even in the presence of correlations and fees.

  13. Household trends in access to improved water sources and sanitation facilities in Vietnam and associated factors: findings from the Multiple Indicator Cluster Surveys, 2000-2011.

    Science.gov (United States)

    Tuyet-Hanh, Tran Thi; Lee, Jong-Koo; Oh, Juhwan; Van Minh, Hoang; Ou Lee, Chul; Hoan, Le Thi; Nam, You-Seon; Long, Tran Khanh

    2016-01-01

    Despite progress made by the Millennium Development Goal (MDG) number 7.C, Vietnam still faces challenges with regard to the provision of access to safe drinking water and basic sanitation. This paper describes household trends in access to improved water sources and sanitation facilities separately, and analyses factors associated with access to improved water sources and sanitation facilities in combination. Secondary data from the Vietnam Multiple Indicator Cluster Survey in 2000, 2006, and 2011 were analyzed. Descriptive statistics and tests of significance describe trends over time in access to water and sanitation by location, demographic and socio-economic factors. Binary logistic regressions (2000, 2006, and 2011) describe associations between access to water and sanitation, and geographic, demographic, and socio-economic factors. There have been some outstanding developments in access to improved water sources and sanitation facilities from 2000 to 2011. In 2011, the proportion of households with access to improved water sources and sanitation facilities reached 90% and 77%, respectively, meeting the 2015 MDG targets for safe drinking water and basic sanitation set at 88% and 75%, respectively. However, despite these achievements, in 2011, only 74% of households overall had access to combined improved drinking water and sanitation facilities. There were also stark differences between regions. In 2011, only 47% of households had access to both improved water and sanitation facilities in the Mekong River Delta compared with 94% in the Red River Delta. In 2011, households in urban compared to rural areas were more than twice as likely (odds ratio [OR]: 2.2; 95% confidence interval [CI]: 1.9-2.5) to have access to improved water and sanitation facilities in combination, and households in the highest compared with the lowest wealth quintile were over 40 times more likely (OR: 42.3; 95% CI: 29.8-60.0). More efforts are required to increase household access to

  14. A Locust Phase Change Model with Multiple Switching States and Random Perturbation

    Science.gov (United States)

    Xiang, Changcheng; Tang, Sanyi; Cheke, Robert A.; Qin, Wenjie

    2016-12-01

    Insects such as locusts and some moths can transform from a solitarious phase when they remain in loose populations and a gregarious phase, when they may swarm. Therefore, the key to effective management of outbreaks of species such as the desert locust Schistocercagregaria is early detection of when they are in the threshold state between the two phases, followed by timely control of their hopper stages before they fledge because the control of flying adult swarms is costly and often ineffective. Definitions of gregarization thresholds should assist preventive control measures and avoid treatment of areas that might not lead to gregarization. In order to better understand the effects of the threshold density which represents the gregarization threshold on the outbreak of a locust population, we developed a model of a discrete switching system. The proposed model allows us to address: (1) How frequently switching occurs from solitarious to gregarious phases and vice versa; (2) When do stable switching transients occur, the existence of which indicate that solutions with larger amplitudes can switch to a stable attractor with a value less than the switching threshold density?; and (3) How does random perturbation influence the switching pattern? Our results show that both subsystems have refuge equilibrium points, outbreak equilibrium points and bistable equilibria. Further, the outbreak equilibrium points and bistable equilibria can coexist for a wide range of parameters and can switch from one to another. This type of switching is sensitive to the intrinsic growth rate and the initial values of the locust population, and may result in locust population outbreaks and phase switching once a small perturbation occurs. Moreover, the simulation results indicate that the switching transient patterns become identical after some generations, suggesting that the evolving process of the perturbation system is not related to the initial value after some fixed number of

  15. Fabrication and properties of nanoscale multiferroic heterostructures for application in magneto-electric random access memory (MERAM) devices

    Science.gov (United States)

    Kim, Gunwoo

    Magnetoelectric random access memory (MERAM) has emerged as a promising new class of non-volatile solid-state memory device. It offers nondestructive reading along with low power consumption during the write operation. A common implementation of MERAM involves use of multiferroic tunneling junctions (MFTJs), which besides offering non-volatility are both electrically and magnetically tunable. Fundamentally, a MFTJ consists of a heterostructure of an ultrathin multiferroic or ferroelectric material as the active tunneling barrier sandwiched between ferromagnetic electrodes. Thereby, the MFTJ exhibits both tunnel electroresistance (TER) and tunnel magnetoresistance (TMR) effects with application of an electric and magnetic field, respectively. In this thesis work, we have developed two-dimensional (2D) thin-film multiferroic heterostructure METJ prototypes consisting of ultrathin ferroelectric BaTiO3 (BTO) layer and a conducting ferromagnetic La0.67Sr 0.33MnO3 (LSMO) electrode. The heteroepitaxial films are grown using the pulsed laser deposition (PLD) technique. This oxide heterostructure offers the opportunity to study the nano-scale details of the tunnel electroresistance (TER) effect using scanning probe microscopy techniques. We performed the measurements using the MFP-3D (Asylum Research) scanning probe microscope. The ultrathin BTO films (1.2-2.0 nm) grown on LSMO electrodes display both ferro- and piezo-electric properties and exhibit large tunnel resistance effect. We have explored the growth and properties of one-dimensional (1D) heterostructures, referred to as multiferoric nanowire (NW) heterostructures. The ferromagnetic/ferroelectric composite heterostructures are grown as sheath layers using PLD on lattice-matched template NWs, e.g. MgO, that are deposited by chemical vapor deposition utilizing the vapor-liquid-solid (VLS) mechanism. The one-dimensional geometry can substantially overcome the clamping effect of the substrate present in two

  16. An energy-efficient SIMD DSP with multiple VLIW configurations and an advanced memory access unit for LTE-A modem LSIs

    Science.gov (United States)

    Tomono, Mitsuru; Ito, Makiko; Nomura, Yoshitaka; Mouri, Makoto; Hirose, Yoshio

    2015-12-01

    Energy efficiency is the most important factor in the design of wireless modem LSIs for mobile handset systems. We have developed an energy-efficient SIMD DSP for LTE-A modem LSIs. Our DSP has mainly two hardware features in order to reduce energy consumption. The first one is multiple VLIW configurations to minimize accesses to instruction memories. The second one is an advanced memory access unit to realize complex memory accesses required for wireless baseband processing. With these features, performance of our DSP is about 1.7 times faster than a base DSP on average for standard LTE-A Libraries. Our DSP achieves about 20% improvement in energy efficiency compared to a base DSP for LTE-A modem LSIs.

  17. MRI in multiple sclerosis: an intra-individual, randomized and multicentric comparison of gadobutrol with gadoterate meglumine at 3 T

    Energy Technology Data Exchange (ETDEWEB)

    Saake, Marc; Weibart, Marina; Doerfler, Arnd [University of Erlangen-Nuremberg, Department of Neuroradiology, Erlangen (Germany); Langner, Soenke; Hosten, Norbert [University Medicine Greifswald, Institute for Diagnostic Radiology and Neuroradiology, Greifswald (Germany); Schwenke, Carsten [SCO:SSiS, Statistical Consulting, Berlin (Germany); Jansen, Olav [University of Kiel, Department of Radiology and Neuroradiology, Kiel (Germany)

    2016-03-15

    To compare contrast effects of gadobutrol with gadoterate meglumine for brain MRI in multiple sclerosis (MS) in a multicentre, randomized, prospective, intraindividual study at 3 T. Institutional review board approval was obtained. Patients with known or suspected active MS lesions were included. Two identical MRIs were performed using randomized contrast agent order. Four post-contrast T1 sequences were acquired (start time points 0, 3, 6 and 9 min). If no enhancing lesion was present in first MRI, second MRI was cancelled. Quantitative (number and signal intensity of enhancing lesions) and qualitative parameters (time points of first and all lesions enhancing; subjective preference regarding contrast enhancement and lesion delineation; global preference) were evaluated blinded. Seventy-four patients (male, 26; mean age, 35 years) were enrolled in three centres. In 45 patients enhancing lesions were found. Number of enhancing lesions increased over time for both contrast agents without significant difference (median 2 for both). Lesions signal intensity was significantly higher for gadobutrol (p < 0.05 at time points 3, 6 and 9 min). Subjective preference rating showed non-significant tendency in favour of gadobutrol. Both gadobutrol and gadoterate meglumine can be used for imaging of acute inflammatory MS lesions. However, gadobutrol generates higher lesion SI. (orig.)

  18. Multiple trait model combining random regressions for daily feed intake with single measured performance traits of growing pigs

    Directory of Open Access Journals (Sweden)

    Künzi Niklaus

    2002-01-01

    Full Text Available Abstract A random regression model for daily feed intake and a conventional multiple trait animal model for the four traits average daily gain on test (ADG, feed conversion ratio (FCR, carcass lean content and meat quality index were combined to analyse data from 1 449 castrated male Large White pigs performance tested in two French central testing stations in 1997. Group housed pigs fed ad libitum with electronic feed dispensers were tested from 35 to 100 kg live body weight. A quadratic polynomial in days on test was used as a regression function for weekly means of daily feed intake and to escribe its residual variance. The same fixed (batch and random (additive genetic, pen and individual permanent environmental effects were used for regression coefficients of feed intake and single measured traits. Variance components were estimated by means of a Bayesian analysis using Gibbs sampling. Four Gibbs chains were run for 550 000 rounds each, from which 50 000 rounds were discarded from the burn-in period. Estimates of posterior means of covariance matrices were calculated from the remaining two million samples. Low heritabilities of linear and quadratic regression coefficients and their unfavourable genetic correlations with other performance traits reveal that altering the shape of the feed intake curve by direct or indirect selection is difficult.

  19. Influence of yoga and aerobics exercise on fatigue, pain and psychosocial status in patients with multiple sclerosis: a randomized trial.

    Science.gov (United States)

    Hasanpour Dehkordi, Ali

    2016-11-01

    Multiple sclerosis (MS) is an autoimmune disease involving brain and spinal cord. Weakness, cognitive impairment, pain, depression and fatigue, as common symptoms of MS, may significantly affect on general health of MS patients. This study aimed to investigate the influence of yoga and aerobic exercise on fatigue, pain, and psychosocial status among these patients. In a randomized clinical trial study on 90 patients whom were randomly assigned to three equal groups of yoga exercises, aerobics exercises, and control group. The exercise program was performed as three sessions per week for 12 weeks. The exercise program included 40 minutes, including 5-10 minutes for warm-up, 25-30 minutes of exercise (walking), and 5 minutes for cooling down. Yoga exercises were scheduled three sessions a week for 12 weeks as well. There was no significant difference in fatigue, pain severity and psychological status among three groups prior to the study, but after the study, in yoga and exercise groups, fatigue physical function, physical and emotional role which patients play throughout daily life, social function, energy, mental status and overall hygiene increased, and the pain and fatigue were relieved in the patients. Yoga and aerobics exercise could decrease some of the MS symptoms, therapeutic costs, hospital stay, and days lost from work as well as increasing the patients' efficiency.

  20. Patient-Reported Outcomes following Single- and Multiple-Radius Total Knee Replacement: A Randomized, Controlled Trial.

    Science.gov (United States)

    Mushtaq, Nadeem; Liddle, Alexander D; Isaac, David; Dillow, Katherine; Gill, Paul

    2017-05-05

    Although single-radius (SR) designs of total knee replacement (TKR) have theoretical benefits, the clinical advantage conferred by such designs is unknown. The aim of this randomized, controlled study was to compare the short-term clinical outcomes of the two design rationales. A total of 105 knees were randomized to receive either a single radius (Scorpio, Stryker; SR Group) or multiple radius (AGC, Zimmer Biomet; MR group) TKR. Patient-reported outcomes (Oxford Knee Score [OKS] and Knee Society Score [KSS]) were collected at 6 weeks, 6 months, and 1 year following surgery. No knees were revised. There was no difference in primary outcomes: OKS was 39.5 (95% confidence interval [CI]: 36.9-42.1) in the SR group and 38.1 (95% CI: 36.0-40.3) in the MR group (p = 0.40). KSS was 168.4 (95% CI: 159.8-177.0) in the SR group; 159.5 (95% CI 150.5-168.5) in the MR group (p = 0.16). There was a small but statistically significant difference in the degree of change of the objective subscale of the KSS, favoring the SR design (p = 0.04), but this is of uncertain clinical relevance. The reported benefits of SR designs do not provide demonstrable functional advantages in the short term. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  1. A randomized controlled trial and cost-effectiveness analysis of early cannulation arteriovenous grafts versus tunneled central venous catheters in patients requiring urgent vascular access for hemodialysis.

    Science.gov (United States)

    Aitken, Emma; Thomson, Peter; Bainbridge, Leigh; Kasthuri, Ram; Mohr, Belinda; Kingsmore, David

    2017-03-01

    Early cannulation arteriovenous grafts (ecAVGs) are proposed as an alternative to tunneled central venous catheters (TCVCs) in patients requiring immediate vascular access for hemodialysis (HD). We compared bacteremia rates in patients treated with ecAVG and TCVC. The study randomized 121 adult patients requiring urgent vascular access for HD in a 1:1 fashion to receive an ecAVG with or without (+/-) an arteriovenous fistula (AVF; n = 60) or TCVC+/-AVF (n = 61). Patients were excluded if they had active systemic sepsis, no anatomically suitable vessels, or an anticipated life expectancy vascular access for HD. The strategy also proved to be cost-neutral. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

  2. Statistics of α-μ Random Variables and Their Applications inWireless Multihop Relaying and Multiple Scattering Channels

    KAUST Repository

    Wang, Kezhi

    2015-06-01

    Exact results for the probability density function (PDF) and cumulative distribution function (CDF) of the sum of ratios of products (SRP) and the sum of products (SP) of independent α-μ random variables (RVs) are derived. They are in the form of 1-D integral based on the existing works on the products and ratios of α-μ RVs. In the derivation, generalized Gamma (GG) ratio approximation (GGRA) is proposed to approximate SRP. Gamma ratio approximation (GRA) is proposed to approximate SRP and the ratio of sums of products (RSP). GG approximation (GGA) and Gamma approximation (GA) are used to approximate SP. The proposed results of the SRP can be used to calculate the outage probability (OP) for wireless multihop relaying systems or multiple scattering channels with interference. The proposed results of the SP can be used to calculate the OP for these systems without interference. In addition, the proposed approximate result of the RSP can be used to calculate the OP of the signal-To-interference ratio (SIR) in a multiple scattering system with interference. © 1967-2012 IEEE.

  3. Intravenous Hydroxypropyl β-Cyclodextrin Formulation of Letermovir: A Phase I, Randomized, Single-Ascending, and Multiple-Dose Trial.

    Science.gov (United States)

    Erb-Zohar, K; Kropeit, D; Scheuenpflug, J; Stobernack, H-P; Hulskotte, Egj; van Schanke, A; Zimmermann, H; Rübsamen-Schaeff, H

    2017-07-04

    Letermovir is a novel antiviral in clinical development for prophylaxis against human cytomegalovirus in immunocompromised transplant recipients. This two-part, single-center, randomized, double-blind, placebo-controlled trial evaluated the safety and pharmacokinetics of a hydroxypropyl β-cyclodextrin (HPβCD)-based intravenous formulation of letermovir in healthy women. Subjects received single, escalating doses (120, 240, 480, 720, and 960 mg; 6 letermovir, 2 placebo per cohort) or multiple, once-daily doses (240 mg; 8 letermovir, 4 placebo) of HPβCD-formulated letermovir and the associated pharmacokinetic profiles and adverse events were investigated. Single-dose and multiple-dose regimens were generally well tolerated. Single-dose escalation resulted in a slightly more-than-dose-proportional increase in the area under the letermovir plasma concentration-time curve (AUC), whereas increase in the maximal observed letermovir plasma concentration (Cmax ) was dose proportional. After once-daily dosing, accumulation ratios in AUC and Cmax were 1.22 and 1.03, respectively. The terminal half-life was 28.3 h, supporting once-daily dosing (EudraCT Number: 2012-001603-20). © 2017 The Authors. Clinical and Translational Science published by Wiley Periodicals, Inc. on behalf of American Society for Clinical Pharmacology and Therapeutics.

  4. The effect of maternal multiple micronutrient supplementation on cognition and mood during pregnancy and postpartum in Indonesia: a randomized trial.

    Directory of Open Access Journals (Sweden)

    Elizabeth L Prado

    Full Text Available Maternal caregiving capacity, which is affected in part by cognition and mood, is crucial for the health of mothers and infants. Few interventions aim to improve maternal and infant health through improving such capacity. Multiple micronutrient (MMN supplementation may improve maternal cognition and mood, since micronutrients are essential for brain function. We assessed mothers who participated in the Supplementation with Multiple Micronutrients Intervention Trial (SUMMIT, a double-blind cluster-randomized trial in Indonesia comparing MMN supplementation to iron and folic acid (IFA during pregnancy and until three months postpartum. We adapted a set of well-studied tests of cognition, motor dexterity, and mood to the local context and administered them to a random sample of 640 SUMMIT participants after an average of 25 weeks (SD = 9 of supplementation. Analysis was by intention to treat. Controlling for maternal age, education, and socio-economic status, MMN resulted in a benefit of 0.12 SD on overall cognition, compared to IFA (95%CI 0.03-0.22, p = .010, and a benefit of 0.18 SD on reading efficiency (95%CI 0.02-0.35, p = .031. Both effects were found particularly in anemic (hemoglobin<110 g/L; overall cognition: B = 0.20, 0.00-0.41, p = .055; reading: B = 0.40, 0.02-0.77, p = .039 and undernourished (mid-upper arm circumference<23.5 cm; overall cognition: B = 0.33, 0.07-0.59, p = .020; reading: B = 0.65, 0.19-1.12, p = .007 mothers. The benefit of MMN on overall cognition was equivalent to the benefit of one year of education for all mothers, to two years of education for anemic mothers, and to three years of education for undernourished mothers. No effects were found on maternal motor dexterity or mood. This is the first study demonstrating an improvement in maternal cognition with MMN supplementation. This improvement may increase the quality of care mothers provide for their infants, potentially partly mediating effects of maternal MMN

  5. The effects of video-game training on broad cognitive transfer in multiple sclerosis: A pilot randomized controlled trial.

    Science.gov (United States)

    Janssen, Alisha; Boster, Aaron; Lee, HyunKyu; Patterson, Beth; Prakash, Ruchika Shaurya

    2015-01-01

    Multiple sclerosis (MS) is a neurodegenerative disease of the central nervous system that results in diffuse nerve damage and associated physical and cognitive impairments. Of the few comprehensive rehabilitation options that exist for populations with lower baseline cognitive functioning, those that have been successful at eliciting broad cognitive improvements have focused on a multimodal training approach, emphasizing complex cognitive processing that utilizes multiple domains simultaneously. The current study sought to determine the feasibility of an 8-week, hybrid-variable priority training (HVT) program, with a secondary aim to assess the success of this training paradigm at eliciting broad cognitive transfer effects. Capitalizing on the multimodal training modalities offered by the Space Fortress platform, we compared the HVT strategy-based intervention with a waitlist control group, to primarily assess skill acquisition and secondarily determine presence of cognitive transfer. Twenty-eight participants met inclusionary criteria for the study and were randomized to either training or waitlist control groups. To assess broad transfer effects, a battery of neuropsychological tests was administered pre- and post-intervention. The results indicated an overall improvement in skill acquisition and evidence for the feasibility of the intervention, but a lack of broad transfer to tasks of cognitive functioning. Participants in the training group, however, did show improvements on a measure of spatial short-term memory. The current investigation provided support for the feasibility of a multimodal training approach, using the HVT strategy, within the MS population, but lacked broad transfer to multiple domains of cognitive functioning. Future improvements to obtain greater cognitive transfer efficacy would include a larger sample size, a longer course of training to evoke greater game score improvement, the inclusion of only cognitively impaired individuals, and

  6. Responsiveness of Myofascial Trigger Points to Single and Multiple Trigger Point Release Massages: A Randomized, Placebo Controlled Trial.

    Science.gov (United States)

    Moraska, Albert F; Schmiege, Sarah J; Mann, John D; Butryn, Nathan; Krutsch, Jason P

    2017-09-01

    This study aimed to assess the effects of single and multiple massage treatments on pressure-pain threshold (PPT) at myofascial trigger points (MTrPs) in people with myofascial pain syndrome expressed as tension-type headache. Individuals (n = 62) with episodic or chronic tension-type headache were randomized to receive 12 twice-weekly 45-min massage or sham ultrasound sessions or wait-list control. Massage focused on trigger point release (ischemic compression) of MTrPs in the bilateral upper trapezius and suboccipital muscles. PPT was measured at MTrPs with a pressure algometer pre and post the first and final (12th) treatments. PPT increased across the study timeframe in all four muscle sites tested for massage, but not sham ultrasound or wait-list groups (P pain threshold of MTrPs have a great capacity to increase; even after multiple massage treatments additional gain in PPT was observed. Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES: Upon completion of this article, the reader should be able to: (1) Understand the contribution of myofascial trigger points to myofascial pain; (2) Describe an effective treatment for decreasing tenderness of a myofascial trigger point; and (3) Discuss the relative values of single vs. multiple massage sessions on increasing pressure-pain thresholds at myofascial trigger points. Advanced ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 0.5 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

  7. Thirty-Month Complete Response as a Surrogate End Point in First-Line Follicular Lymphoma Therapy: An Individual Patient-Level Analysis of Multiple Randomized Trials.

    Science.gov (United States)

    Shi, Qian; Flowers, Christopher R; Hiddemann, Wolfgang; Marcus, Robert; Herold, Michael; Hagenbeek, Anton; Kimby, Eva; Hochster, Howard; Vitolo, Umberto; Peterson, Bruce A; Gyan, Emmanuel; Ghielmini, Michele; Nielsen, Tina; De Bedout, Sabine; Fu, Tommy; Valente, Nancy; Fowler, Nathan H; Hoster, Eva; Ladetto, Marco; Morschhauser, Franck; Zucca, Emanuele; Salles, Gilles; Sargent, Daniel J

    2017-02-10

    Purpose Follicular lymphoma (FL) is an indolent cancer, with effective but rarely curative treatment options. As a standard study end point for first-line FL therapy, progression-free survival (PFS) requires extended follow-up (median PFS, > 7 years). To provide patients with earlier access to newer therapies, an earlier end point to expedite clinical trials is needed. Our objective was to formally assess the complete response rate at 30 months (CR30) after initiation of induction therapy as a potential surrogate end point for PFS in first-line FL therapy. Patients and Methods We analyzed individual patient data from 13 randomized multicenter trials of induction and maintenance regimens in first-line FL therapy published after 1990 and with sufficient data to evaluate whether CR30 could predict treatment effects on PFS. Correlation of the CR30 odds ratio with the PFS hazard ratio was evaluated by both linear regression (R2WLS) and bivariate copula (R2Copula) models. Prespecified criteria for surrogacy required either R2WLS or R2Copula ≥ 0.80, with a lower-bound 95% CI > 0.60. Results Data from eight induction and five maintenance randomized trials in 3,837 evaluable patients were analyzed. The prespecified surrogacy threshold was met, with an R2WLS of 0.88 (95% CI, 0.77 to 0.96) and an R2Copula of 0.86 (95% CI, 0.72 to 1.00). Multiple sensitivity and supplemental analyses supported the robustness of the findings. A minimum 11% absolute improvement in CR30 from a 50% control rate predicted a significant treatment effect on PFS (hazard ratio, 0.69). Conclusion This large, prospective, pooled analysis of randomized chemotherapy, immunotherapy, and chemoimmunotherapy trials demonstrates that CR30 is a surrogate end point for PFS in first-line FL treatment trials. Use of this end point may expedite therapeutic development with the intent of bringing novel therapies to this patient population years before PFS results are mature.

  8. Healthcare access challenges facing six African refugee mothers in South Korea: a qualitative multiple-case study.

    Science.gov (United States)

    Kim, Min Sun; Song, In Gyu; An, Ah Reum; Kim, Kyae Hyung; Sohn, Ji Hoon; Yang, Sei Won

    2017-05-01

    Following legal reform in 2013, the annual number of asylum seekers entering South Korea has increased from 1,143 in 2012 to 5,711 in 2015. We interviewed six African refugee mothers of young children regarding their health needs and barriers to access maternal child health services. We recruited mothers who had visited a clinic for immigrants between July 2013 and August 2015. Participants were African refugee women, aged over 18 years, who had given birth in Korea within the previous 5 years and had come to Korea over a year before recruitment. Interview questions examined participants' experiences in pregnancy and childbirth and concerns regarding their child's health status. Initial data analysis involved all researchers' immersion in the entire collection of transcripts. We then noted recurrent topics and themes and identified similar issues. At the time of giving birth, 5 participants were asylum seekers and one had undocumented status. The following barriers impeded their access to maternal child healthcare: socioeconomic factors (unstable social identity, low economic status, difficulty obtaining health insurance), language barriers (lack of linguistically appropriate health information, limited access to translation services), and cultural barriers (religious and cultural differences). Weak social support also hindered access to healthcare soon after migration; however, social links with the community emerged as a key coping strategy following settlement. We identified barriers to maternal and child healthcare and coping strategies among African refugee mothers in Korea. Future research should assess refugees' health status and improve health access and literacy among refugee mothers.

  9. Zinc or multiple micronutrient supplementation to reduce diarrhea and respiratory disease in South African children: a randomized controlled trial.

    Directory of Open Access Journals (Sweden)

    Kany-Kany Angelique Luabeya

    2007-06-01

    Full Text Available Prophylactic zinc supplementation has been shown to reduce diarrhea and respiratory illness in children in many developing countries, but its efficacy in children in Africa is uncertain.To determine if zinc, or zinc plus multiple micronutrients, reduces diarrhea and respiratory disease prevalence.Randomized, double-blind, controlled trial.Rural community in South Africa.THREE COHORTS: 32 HIV-infected children; 154 HIV-uninfected children born to HIV-infected mothers; and 187 HIV-uninfected children born to HIV-uninfected mothers.Children received either 1250 IU of vitamin A; vitamin A and 10 mg of zinc; or vitamin A, zinc, vitamins B1, B2, B6, B12, C, D, E, and K and copper, iodine, iron, and niacin starting at 6 months and continuing to 24 months of age. Homes were visited weekly.Primary outcome was percentage of days of diarrhea per child by study arm within each of the three cohorts. Secondary outcomes were prevalence of upper respiratory symptoms and percentage of children who ever had pneumonia by maternal report, or confirmed by the field worker.Among HIV-uninfected children born to HIV-infected mothers, median percentage of days with diarrhea was 2.3% for 49 children allocated to vitamin A; 2.5% in 47 children allocated to receive vitamin A and zinc; and 2.2% for 46 children allocated to multiple micronutrients (P = 0.852. Among HIV-uninfected children born to HIV-uninfected mothers, median percentage of days of diarrhea was 2.4% in 56 children in the vitamin A group; 1.8% in 57 children in the vitamin A and zinc group; and 2.7% in 52 children in the multiple micronutrient group (P = 0.857. Only 32 HIV-infected children were enrolled, and there were no differences between treatment arms in the prevalence of diarrhea. The prevalence of upper respiratory symptoms or incidence of pneumonia did not differ by treatment arms in any of the cohorts.When compared with vitamin A alone, supplementation with zinc, or with zinc and multiple

  10. Rapid selection of accessible and cleavable sites in RNA by Escherichia coli RNase P and random external guide sequences

    OpenAIRE

    Lundblad, Eirik W.; Xiao, Gaoping; Ko, Jae-hyeong; Altman, Sidney

    2008-01-01

    A method of inhibiting the expression of particular genes by using external guide sequences (EGSs) has been improved in its rapidity and specificity. Random EGSs that have 14-nt random sequences are used in the selection procedure for an EGS that attacks the mRNA for a gene in a particular location. A mixture of the random EGSs, the particular target RNA, and RNase P is used in the diagnostic procedure, which, after completion, is analyzed in a gel with suitable control lanes. Within a few ho...

  11. Effects of Home Access to Active Videogames on Child Self-Esteem, Enjoyment of Physical Activity, and Anxiety Related to Electronic Games: Results from a Randomized Controlled Trial.

    Science.gov (United States)

    Abbott, Rebecca A; Smith, Anne J; Howie, Erin K; Pollock, Clare; Straker, Leon

    2014-08-01

    Active-input videogames could provide a useful conduit for increasing physical activity by improving a child's self-confidence, physical activity enjoyment, and reducing anxiety. Therefore this study evaluated the impact of (a) the removal of home access to traditional electronic games or (b) their replacement with active-input videogames, on child self-perception, enjoyment of physical activity, and electronic game use anxiety. This was a crossover, randomized controlled trial, conducted over a 6-month period in participants' family homes in metropolitan Perth, Australia, from 2007 to 2010. Children 10-12 years old were recruited through school and community media. Of 210 children who were eligible, 74 met inclusion criteria, and 8 withdrew, leaving 66 children (33 girls) for analysis. A counterbalanced randomized order of three conditions sustained for 8 weeks each: No home access to electronic games, home access to traditional electronic games, and home access to active-input electronic games. Perception of self-esteem (Harter's Self Perception Profile for Children), enjoyment of physical activity (Physical Activity Enjoyment Scale questionnaire), and anxiety toward electronic game use (modified Loyd and Gressard Computer Anxiety Subscale) were assessed. Compared with home access to traditional electronic games, neither removal of all electronic games nor replacement with active-input games resulted in any significant change to child self-esteem, enjoyment of physical activity, or anxiety related to electronic games. Although active-input videogames have been shown to be enjoyable in the short term, their ability to impact on psychological outcomes is yet to be established.

  12. Identification and Classification of Orthogonal Frequency Division Multiple Access (OFDMA) Signals Used in Next Generation Wireless Systems

    Science.gov (United States)

    2012-03-01

    phase ISI inter-symbol interference xiv LDPC low-density parity codes MAC media access control MATLAB matrix laboratory MPDU MAC protocol...convolutional coding (ZCC), and low-density parity codes ( LDPC ). These are all supported at a variety of rates as summarized in Table 7. Table 7

  13. Multiple Motives, Conflicting Conceptions: Parsing the Contexts of Differentiated Access to Scientific Information in the Federal Government

    Science.gov (United States)

    Oltmann, Shannon M.

    2012-01-01

    Scientific information, used by the U.S. federal government to formulate public policy in many arenas, is frequently contested and sometimes altered, blocked from publication, deleted from reports, or restricted in some way. This dissertation examines how and why restricted access to science policy (RASP) occurs through a comparative case study.…

  14. Home-based balance training using the Wii balance board: a randomized, crossover pilot study in multiple sclerosis.

    Science.gov (United States)

    Prosperini, Luca; Fortuna, Deborah; Giannì, Costanza; Leonardi, Laura; Marchetti, Maria Rita; Pozzilli, Carlo

    2013-01-01

    To evaluate the effectiveness of a home-based rehabilitation of balance using the Nintendo Wii Balance Board System (WBBS) in patients affected by multiple sclerosis (MS). In this 24-week, randomized, 2-period crossover pilot study, 36 patients having an objective balance disorder were randomly assigned in a 1:1 ratio to 2 counterbalanced arms. Group A started a 12-week period of home-based WBBS training followed by a 12-week period without any intervention; group B received the treatment in reverse order. As endpoints, we considered the mean difference (compared with baseline) in force platform measures (i.e., the displacement of body center of pressure in 30 seconds), 4-step square test (FSST), 25-foot timed walking test (25-FWT), and 29-item MS Impact Scale (MSIS-29), as evaluated after 12 weeks and at the end of the 24-week study period. The 2 groups did not differ in baseline characteristics. Repeated-measures analyses of variance showed significant time × treatment effects, indicating that WBBS was effective in ameliorating force platform measures (F = 4.608, P = .016), FSST (F = 3.745, P = .034), 25-FWT (F = 3.339, P = .048), and MSIS-29 (F = 4.282, P = .023). Five adverse events attributable to the WBSS training (knee or low back pain) were recorded, but only 1 patient had to retire from the study. A home-based WBBS training might potentially provide an effective, engaging, balance rehabilitation solution for people with MS. However, the risk of WBBS training-related injuries should be carefully balanced with benefits. Further studies, including cost-effectiveness analyses, are warranted to establish whether WBBS may be useful in the home setting.

  15. Effects of aerobic and strength exercise on motor fatigue in men and women with multiple sclerosis: a randomized controlled trial.

    Science.gov (United States)

    Surakka, Jukka; Romberg, Anders; Ruutiainen, Juhani; Aunola, Sirkka; Virtanen, Arja; Karppi, Sirkka-Liisa; Mäentaka, Kari

    2004-11-01

    To investigate the effects of aerobic and strength exercise on motor fatigue of knee flexor and extensor muscles in subjects with multiple sclerosis (MS). A randomized controlled trial. At Masku Neurological Rehabilitation Centre, Masku, and the Social Insurance Institution, Research Department, Turku, Finland. Ninety-five MS patients with mild to moderate disability were randomized into exercise group (n =47) and a control group (n =48). Participants in the exercise group attended in a supervised exercise period of three weeks, which was followed by a home exercise programme lasting for 23 weeks. Patients in the control group continued with their normal living. Motor fatigue of knee flexor and extensor muscles was measured during a static 30-s maximal sustained muscle contraction. The decline in force (Nm) during the 30 s was recorded, and a fatigue index (FI) was calculated. Subjective fatigue was measured by using the Fatigue Severity Scale (FSS). The Ambulatory Fatigue Index (AFI) was calculated on the basis of a 500-m walking test. Assessment took place at baseline, at the third week (not for the control group) and at the 26th week. All outcome variables were analysed, men and women together, and some interesting contrasts were analysed by gender. Associations were observed with changes in extension FI and Expanded Disability Status Scale (EDSS) score and mean extension torque (Nm), but not with changes in FI and aerobic or strength exercise activity, mean AFI, mean FSS or in mean knee flexion torque. AFI was decreased in all subject groups (p =0.007). Motor fatigue was reduced in knee flexion (p=0.0014) and extension (ns) among female but not in male exercisers after six months of exercise. The exercise activity of women was 25% higher than that of the men. Six months of exercise reduced motor fatigue in women, but not in men.

  16. Rapid selection of accessible and cleavable sites in RNA by Escherichia coli RNase P and random external guide sequences.

    Science.gov (United States)

    Lundblad, Eirik W; Xiao, Gaoping; Ko, Jae-Hyeong; Altman, Sidney

    2008-02-19

    A method of inhibiting the expression of particular genes by using external guide sequences (EGSs) has been improved in its rapidity and specificity. Random EGSs that have 14-nt random sequences are used in the selection procedure for an EGS that attacks the mRNA for a gene in a particular location. A mixture of the random EGSs, the particular target RNA, and RNase P is used in the diagnostic procedure, which, after completion, is analyzed in a gel with suitable control lanes. Within a few hours, the procedure is complete. The action of EGSs designed by an older method is compared with EGSs designed by the random EGS method on mRNAs from two bacterial pathogens.

  17. The effects of carbamazepine and lorazepam on single versus multiple previous alcohol withdrawals in an outpatient randomized trial.

    Science.gov (United States)

    Malcolm, R; Myrick, H; Roberts, J; Wang, W; Anton, R F; Ballenger, J C

    2002-05-01

    Benzodiazepines are the mainstay of treatment for mild-to-moderate alcohol withdrawal in outpatient settings, but they can interact with alcohol, cause motor incoordination, or be abused. This study compared the therapeutic responses of the benzodiazepine lorazepam and the anticonvulsant carbamazepine for the outpatient treatment of acute alcohol withdrawal in terms of patients' previous detoxification histories, and compared the effects of these 2 medications on drinking behaviors in the immediate postdetoxification period. This was a randomized double-blind trial comparing patient responses to carbamazepine and lorazepam across 2 levels of detoxification histories (0-1 or >or=2 previous medicated detoxifications). A university medical center substance abuse clinic in Charleston, SC. One hundred thirty-six patients in moderate alcohol withdrawal were randomized. Major exclusions were significant hepatic or hematologic abnormalities and use of medications that could alter withdrawal symptoms. Patients received 600-800 mg of carbamazepine or 6-8 mg of lorazepam in divided doses on day 1 tapering to 200 mg of carbamazepine or 2 mg of lorazepam. The Clinical Institute Withdrawal Assessment for Alcohol-Revised was used to assess alcohol withdrawal symptoms on days 1 through 5 and postmedication at days 7 and 12. Daily drinking was measured by patient report using a daily drinking log and a breath alcohol level with each visit. Side effects were recorded daily. Carbamazepine and lorazepam were equally effective at decreasing the symptoms of alcohol withdrawal. In the post-treatment period, 89 patients drank on at least 1 day; on average, carbamazepine patients drank less than 1 drink per drinking day and lorazepam patients drank almost 3 drinks per drinking day (P =.003). Among those with multiple past detoxifications, the carbamazepine group drank less than 1 drink per day on average and the lorazepam group drank about 5 drinks per day on average (P =.033). Lorazepam

  18. A randomized controlled trial of telemonitoring in older adults with multiple chronic conditions: the Tele-ERA study

    Directory of Open Access Journals (Sweden)

    Takahashi Paul Y

    2010-09-01

    Full Text Available Abstract Background Older adults with multiple chronic illnesses are at risk for worsening functional and medical status and hospitalization. Home telemonitoring may help slow this decline. This protocol of a randomized controlled trial was designed to help determine the impact of home telemonitoring on hospitalization. The specific aim of the study reads as follows: to determine the effectiveness of home telemonitoring compared with usual care in reducing the combined outcomes of hospitalization and emergency department visits in an at-risk population 60 years of age or older. Methods/Design Two-hundred patients with the highest 10% Mayo Clinic Elder Risk Assessment scores will be randomly assigned to one of two interventions. Home telemonitoring involves the use of a computer device, the Intel Health Guide, which records biometric and symptom data from patients in their homes. This information is monitored by midlevel providers associated with a primary care medical practice. Under the usual care scenario, patients make appointments with their providers as problems arise and use ongoing support such as a 24-hour nurse line. Patients will have initial evaluations of gait and quality of life using instruments such as the SF-12 Health Survey, the Kokmen Short Test of Mental Status, and the PHQ-9 health questionnaire. Patients will be followed for 1 year for primary outcomes of hospitalizations and emergency department visits. Secondary analysis will include quality of life, compliance with the device, and attitudes about telemonitoring. Sample size is based on an 80% power to detect a 36% difference between the two groups. The primary analysis will involve Cox proportional time-to-event analysis. Secondary analysis will use t-test comparisons for continuous variables and the chi square test for proportional analysis. Discussion Patients randomized to home telemonitoring will have daily assessments of their health status using the device

  19. Integrative psychotherapeutic nursing home program to reduce multiple psychiatric symptoms of cognitively impaired patients and caregiver burden: randomized controlled trial.

    Science.gov (United States)

    Bakker, Ton J E M; Duivenvoorden, Hugo J; van der Lee, Jacqueline; Olde Rikkert, Marcel G M; Beekman, Aartjan T F; Ribbe, Miel W

    2011-06-01

    To test the effectiveness of an integrative psychotherapeutic nursing home program (integrative reactivation and rehabilitation [IRR]) to reduce multiple neuropsychiatry symptoms (MNPS) of cognitively impaired patients and caregiver burden (CB). Randomized controlled trial. Psychiatric-skilled nursing home (IRR) and usual care (UC), consisting of different types of nursing home care at home or in an institution. N = 168 (81 IRR and 87 UC). Patients had to meet classification of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition for dementia, amnestic disorders, or other cognitive disorders. Further inclusion criteria: Neuropsychiatric Inventory (NPI) ≥3; Mini-Mental State Examination ≥18 and ≤27; and Barthel Index (BI) ≥5 and ≤19. IRR consisted of a person-oriented integrative psychotherapeutic nursing home program to reduce MNPS of the patient and CB. UC consisted of different types of nursing home care at home or in an institution, mostly emotion oriented. Primary outcome variable was MNPS (number and sum-severity of NPI). Furthermore, burden and competence of caregiver were also measured. T1 (inclusion), T2 (end of treatment), T3 (after 6 months of follow-up). Cohen's d (Cd) was calculated for mean differences (intention to treat). For confounding, repeated measurement modeling (random regression modeling [RRM]) was applied. In the short term from the perspective of the caregiver, IRR showed up to 34% surplus effects on MNPS of the patients; NPI symptoms: 1.31 lower (Cd, -0.53); and NPI sum- severity: 11.16 lower (Cd, -0.53). In follow-up, the effects were sustained. However, from the perspective of the nursing team, these effects were insignificant, although the trend was in the same direction and correlated significantly with the caregiver results over time (at T3: r = 0.48). In addition, IRR showed surplus effects (up to 36%) on burden and competence of caregiver: NPI emotional distress: 3.78 (Cd, -0.44); CB: 17.69 (Cd, -0

  20. An application of the edge effect in measuring accessibility to multiple food retailer types in Southwestern Ontario, Canada

    Directory of Open Access Journals (Sweden)

    Arku Godwin

    2011-05-01

    Full Text Available Abstract Background Trends in food retailing associated with the consolidation of smaller-format retailers into fewer, larger-format supercentres have left some rural areas with fewer sources of nutritious, affordable food. Access to nutritious, affordable food is essential for good dietary habits and combating health issues such as type-2 diabetes, obesity, and cardiovascular disease. Many studies on food environments use inaccurate or incomplete methods for locating food retailers, which may be responsible for mischaracterising food deserts. This study uses databases of every residence in and every food retailer in and around Middlesex County, Ontario, Canada. Residences were geocoded to their precise address, and network analysis techniques were performed in a geographic information system (GIS to determine distances between every residence and different types of food retailers (grocery stores, fast food, fruit and vegetable sources, grocery stores plus fruit and vegetable sources, variety stores, both when considering and neglecting facilities outside the area of study, to account for a deficiency in analysis termed the 'edge effect'. Results Analysis of household accessibility to food outlets by neighbourhood socioeconomic distress level indicated that residents in the most distressed neighbourhoods tended to have better accessibility to all types of food retailers. In the most distressed neighbourhoods, 79 percent of residences were within walking distance of a grocery store, compared to only 10 percent in the least distressed neighbourhoods. When the edge effect was neglected, 37 percent of distance estimates proved inaccurate. Average accessibility to all food retailer types improved dramatically when food outlets adjacent to the study area were considered, thereby controlling for the edge effect. Conclusion By neglecting to consider food retailers just outside study area boundaries, previous studies may significantly over-report the

  1. An application of the edge effect in measuring accessibility to multiple food retailer types in southwestern Ontario, Canada.

    Science.gov (United States)

    Sadler, Richard C; Gilliland, Jason A; Arku, Godwin

    2011-05-15

    Trends in food retailing associated with the consolidation of smaller-format retailers into fewer, larger-format supercentres have left some rural areas with fewer sources of nutritious, affordable food. Access to nutritious, affordable food is essential for good dietary habits and combating health issues such as type-2 diabetes, obesity, and cardiovascular disease. Many studies on food environments use inaccurate or incomplete methods for locating food retailers, which may be responsible for mischaracterising food deserts. This study uses databases of every residence in and every food retailer in and around Middlesex County, Ontario, Canada. Residences were geocoded to their precise address, and network analysis techniques were performed in a geographic information system (GIS) to determine distances between every residence and different types of food retailers (grocery stores, fast food, fruit and vegetable sources, grocery stores plus fruit and vegetable sources, variety stores), both when considering and neglecting facilities outside the area of study, to account for a deficiency in analysis termed the 'edge effect'. Analysis of household accessibility to food outlets by neighbourhood socioeconomic distress level indicated that residents in the most distressed neighbourhoods tended to have better accessibility to all types of food retailers. In the most distressed neighbourhoods, 79 percent of residences were within walking distance of a grocery store, compared to only 10 percent in the least distressed neighbourhoods. When the edge effect was neglected, 37 percent of distance estimates proved inaccurate. Average accessibility to all food retailer types improved dramatically when food outlets adjacent to the study area were considered, thereby controlling for the edge effect. By neglecting to consider food retailers just outside study area boundaries, previous studies may significantly over-report the actual distance necessary to travel for food. Research on

  2. Acute effects of single and multiple level thoracic manipulations on chronic mechanical neck pain: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Puntumetakul R

    2015-01-01

    Full Text Available Rungthip Puntumetakul,1,2 Thavatchai Suvarnnato,1,3 Phurichaya Werasirirat,1 Sureeporn Uthaikhup,2 Junichiro Yamauchi,4,5 Rose Boucaut6 1School of Physical Therapy, Faculty of Associated Medical Sciences, 2Research Center in Back, Neck, Other Joint Pain and Human Performance, 3Physical Therapy Unit, Srinagarind Hospital, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; 4Graduate School of Human Health Sciences, Tokyo Metropolitan University, 5Future Institute for Sport Sciences, Tokyo, Japan; 6School of Health Sciences (Physiotherapy, University of South Australia, Adelaide, SA, Australia Background: Thoracic spine manipulation has become a popular alternative to local cervical manipulative therapy for mechanical neck pain. This study investigated the acute effects of single-level and multiple-level thoracic manipulations on chronic mechanical neck pain (CMNP.Methods: Forty-eight patients with CMNP were randomly allocated to single-level thoracic manipulation (STM at T6–T7 or multiple-level thoracic manipulation (MTM, or to a control group (prone lying. Cervical range of motion (CROM, visual analog scale (VAS, and the Thai version of the Neck Disability Index (NDI-TH scores were measured at baseline, and at 24-hour and at 1-week follow-up.Results: At 24-hour and 1-week follow-up, neck disability and pain levels were significantly (P<0.05 improved in the STM and MTM groups compared with the control group. CROM in flexion and left lateral flexion were increased significantly (P<0.05 in the STM group when compared with the control group at 1-week follow-up. The CROM in right rotation was increased significantly after MTM compared to the control group (P<0.05 at 24-hour follow-up. There were no statistically significant differences in neck disability, pain level at rest, and CROM between the STM and MTM groups.Conclusion: These results suggest that both single-level and multiple-level thoracic manipulation improve neck disability

  3. A prospective, randomized comparison between single- and multiple-injection techniques for ultrasound-guided subgluteal sciatic nerve block.

    Science.gov (United States)

    Yamamoto, Hiroto; Sakura, Shinichi; Wada, Minori; Shido, Akemi

    2014-12-01

    It is believed that local anesthetic injected to obtain circumferential spread around nerves produces a more rapid onset and successful blockade after some ultrasound-guided peripheral nerve blocks. However, evidence demonstrating this point is limited only to the popliteal sciatic nerve block, which is relatively easy to perform by via a high-frequency linear transducer. In the present study, we tested the hypothesis that multiple injections of local anesthetic to make circumferential spread would improve the rate of sensory and motor blocks compared with a single-injection technique for ultrasound-guided subgluteal sciatic nerve block, which is considered a relatively difficult block conducted with a low-frequency, curved-array transducer. Ninety patients undergoing knee surgery were divided randomly into 2 groups to receive the ultrasound-guided subgluteal approach to sciatic nerve block with 20 mL of 1.5% mepivacaine with epinephrine. For group M (the multiple-injection technique), the local anesthetic was injected to create circumferential spread around the sciatic nerve without limitation on the number of needle passes. For group S (the single-injection technique), the number of needle passes was limited to 1, and the local anesthetic was injected to create spread along the dorsal surface of the sciatic nerve, during which no adjustment of the needle tip was made. Sensory and motor blockade were assessed in double-blind fashion for 30 minutes after completion of the block. The primary outcome was sensory blockade of all sciatic components tested, including tibial, superficial peroneal, and sural nerves at 30 minutes after injection. Data from 86 patients (43 in each group) were analyzed. Block execution took more time for group M than group S. The proportion of patients with complete sensory blockade of all sciatic components at 30 minutes after injection was significantly larger for group M than group S (41.9% vs 16.3%, P = 0.018). Complete motor blockade of

  4. Using IT to improve access, communication, and asthma in African American and Hispanic/Latino Adults: Rationale, design, and methods of a randomized controlled trial.

    Science.gov (United States)

    Apter, Andrea J; Bryant-Stephens, Tyra; Morales, Knashawn H; Wan, Fei; Hardy, Sharmaine; Reed-Wells, Shakira; Dominguez, Maria; Gonzalez, Rodalyn; Mak, NaDea; Nardi, Alyssa; Park, Hami; Howell, John T; Localio, Russell

    2015-09-01

    Asthma morbidity is high among inner-city minority adults. Improving access to care and patient-provider communication are believed to be essential for improving outcomes. Access and communication in turn increasingly rely on information technology including features of the Electronic Health Record. Its patient portal offers web-based communication with providers and practices. How patients with limited resources and educational opportunities can benefit from this portal is unclear. In contrast, home visits by community health workers (CHWs) have improved access to care for asthmatic children and promoted caretaker-clinician communication. We describe the planning, design, and methodology of an ongoing randomized controlled trial for 300 adults, predominantly African American and Hispanic/Latino, with uncontrolled asthma recruited from low income urban neighborhoods who are directed to the most convenient internet access and taught to use the portal, with and without home visits from a CHW. The study 1) compares the effects of the 1-year interventions on asthma outcomes (improved asthma control, quality of life; fewer ED visits and hospitalizations for asthma or any cause), 2) evaluates whether communication (portal use) and access (appointments made/kept) mediate the interventions' effects on asthma outcomes, and 3) investigates effect modification by literacy level, primary language, and convenience of internet access. In home visits, CHWs 1) train patients to competency in portal use, 2) enhance care coordination, 3) communicate the complex social circumstances of patients' lives to providers, and 4) compensate for differences in patients' health literacy skills. The practical challenges to design and implementation in the targeted population are presented. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Microsatellite analysis of Damask rose (Rosa damascena Mill.) accessions from various regions in Iran reveals multiple genotypes.

    Science.gov (United States)

    Babaei, Alireza; Tabaei-Aghdaei, Seyed Reza; Khosh-Khui, Morteza; Omidbaigi, Reza; Naghavi, Mohammad Reza; Esselink, Gerhard D; Smulders, Marinus J M

    2007-03-08

    Damask roses (Rosa damascena Mill.) are mainly used for essential oil production. Previous studies have indicated that all production material in Bulgaria and Turkey consists of only one genotype. Nine polymorphic microsatellite markers were used to analyze the genetic diversity of 40 accessions of R. damascena collected across major and minor rose oil production areas in Iran. All microsatellite markers showed a high level of polymorphism (5-15 alleles per microsatellite marker, with an average of 9.11 alleles per locus). Cluster analysis of genetic similarities revealed that these microsatellites identified a total of nine different genotypes. The genotype from Isfahan province, which is the major production area, was by far the most common genotype (27/40 accessions). It was identical to the Bulgarian genotype. Other genotypes (each represented by 1-4 accessions) were collected from minor production areas in several provinces, notably in the mountainous Northwest of Iran. This is the first study that uncovered genetic diversity within Damask rose. Our results will guide new collection activities to establish larger collections and manage the Iranian Damask rose genetic resources. The genotypes identified here may be directly useful for breeding.

  6. Microsatellite analysis of Damask rose (Rosa damascena Mill. accessions from various regions in Iran reveals multiple genotypes

    Directory of Open Access Journals (Sweden)

    Naghavi Mohammad

    2007-03-01

    Full Text Available Abstract Background Damask roses (Rosa damascena Mill. are mainly used for essential oil production. Previous studies have indicated that all production material in Bulgaria and Turkey consists of only one genotype. Nine polymorphic microsatellite markers were used to analyze the genetic diversity of 40 accessions of R. damascena collected across major and minor rose oil production areas in Iran. Results All microsatellite markers showed a high level of polymorphism (5–15 alleles per microsatellite marker, with an average of 9.11 alleles per locus. Cluster analysis of genetic similarities revealed that these microsatellites identified a total of nine different genotypes. The genotype from Isfahan province, which is the major production area, was by far the most common genotype (27/40 accessions. It was identical to the Bulgarian genotype. Other genotypes (each represented by 1–4 accessions were collected from minor production areas in several provinces, notably in the mountainous Northwest of Iran. Conclusion This is the first study that uncovered genetic diversity within Damask rose. Our results will guide new collection activities to establish larger collections and manage the Iranian Damask rose genetic resources. The genotypes identified here may be directly useful for breeding.

  7. A prospective, randomized, controlled trial of autologous haematopoietic stem cell transplantation for aggressive multiple sclerosis: a position paper.

    Science.gov (United States)

    Saccardi, R; Freedman, M S; Sormani, M P; Atkins, H; Farge, D; Griffith, L M; Kraft, G; Mancardi, G L; Nash, R; Pasquini, M; Martin, R; Muraro, P A

    2012-06-01

    Haematopoietic stem cell transplantation (HSCT) has been tried in the last 15 years as a therapeutic option in patients with poor-prognosis autoimmune disease who do not respond to conventional treatments. Worldwide, more than 600 patients with multiple sclerosis (MS) have been treated with HSCT, most of them having been recruited in small, single-centre, phase 1-2 uncontrolled trials. Clinical and magnetic resonance imaging outcomes from case series reports or Registry-based analyses suggest that a major response is achieved in most patients; quality and duration of response are better in patients transplanted during the relapsing-remitting phase than in those in the secondary progressive stage. An interdisciplinary group of neurologists and haematologists has been formed, following two international meetings supported by the European and American Blood and Marrow Transplantation Societies, for the purpose of discussing a controlled clinical trial, to be designed within the new scenarios of evolving MS treatments. Objectives of the trial, patient selection, transplant technology and outcome assessment were extensively discussed. The outcome of this process is summarized in the present paper, with the goal of establishing the background and advancing the development of a prospective, randomized, controlled multicentre trial to assess the clinical efficacy of HSCT for the treatment of highly active MS.

  8. Large differences in adiponectin levels have no clear effect on multiple sclerosis risk: A Mendelian randomization study.

    Science.gov (United States)

    Devorak, Julia; Mokry, Lauren E; Morris, John A; Forgetta, Vincenzo; Davey Smith, George; Sawcer, Stephen; Richards, J Brent

    2017-10-01

    Mendelian randomization (MR) studies have demonstrated strong support for an association between genetically increased body mass index and risk of multiple sclerosis (MS). The adipokine adiponectin may be a potential mechanism linking body mass to risk of MS. To evaluate whether genetically increased adiponectin levels influence risk of MS. Using genome-wide significant single nucleotide polymorphisms (SNPs) for adiponectin, we undertook an MR study to estimate the effect of adiponectin on MS. This method prevents bias due to reverse causation and minimizes bias due to confounding. Sensitivity analyses were performed to evaluate the assumptions of MR. MR analyses did not support a role for genetically elevated adiponectin in risk of MS (odds ratio (OR) = 0.93 per unit increase in natural-log-transformed adiponectin, equivalent to a two-standard deviation increase in adiponectin on the absolute scale; 95% confidence interval (CI) = 0.66-1.33; p = 0.61). Further MR analysis suggested that genetic variation at the adiponectin gene, which influences adiponectin level, does not impact MS risk. Sensitivity analyses, including MR-Egger regression, suggested no bias due to pleiotropy. Lifelong genetically increased adiponectin levels in humans have no clear effect on risk of MS. Other biological factors driving the association between body mass and MS should be investigated.

  9. Prenatal food supplementation fortified with multiple micronutrients increases birth length: a randomized controlled trial in rural Burkina Faso.

    Science.gov (United States)

    Huybregts, Lieven; Roberfroid, Dominique; Lanou, Hermann; Menten, Joris; Meda, Nicolas; Van Camp, John; Kolsteren, Patrick

    2009-12-01

    Prenatal multiple micronutrient (MMN) or balanced energy and protein supplementation has a limited effect on birth size of the offspring. The objective was to determine whether a prenatal MMN-fortified food supplement (FFS) improves anthropometric measures at birth compared with supplementation with an MMN pill alone. We conducted a nonblinded, individually randomized controlled trial in 1296 pregnant women in 2 villages in rural Burkina Faso. Supplements were provided on a daily basis, and compliance was closely verified by using a community-based network of home visitors. Anthropometric measures at birth were available for analysis for 87% of the 1175 live singleton deliveries enrolled. After adjustment for gestational age at birth, the FFS group had a significantly higher birth length (+4.6 mm; P = 0.001). FFS supplementation resulted in a modestly higher birth weight (+31 g; P = 0.197). Subgroup analyses showed clinically important treatment effects on birth length (+12.0 mm; P = 0.005) and on birth weight (+111 g; P = 0.133) for underweight [body mass index (in kg/m(2)) birth to longer newborns (+7.3 mm; P = 0.002) than did those who received MMN supplementation. The provision of FFS to pregnant women resulted in higher birth length than did MMN supplementation. For women with a suboptimal prepregnancy nutritional status, MMN supplementation should be complemented with a balanced energy and protein supplement to produce a clinical effect on birth size. The trial was registered at clinicaltrials.gov as NCT00909974.

  10. A group-delivered self-management program reduces spasticity in people with multiple sclerosis: A randomized, controlled pilot trial

    Science.gov (United States)

    Bourdette, Dennis; Chen, Yiyi; Chen, Zunqiu; Cameron, Michelle

    2017-01-01

    Background Spasticity affects more than 80% of people with multiple sclerosis (MS), affecting activity, participation, and quality of life. Based on an international guideline, an MS spasticity group education and stretching program, MS Spasticity: Take Control (STC), has been developed. Objective The objective of this paper is to determine whether STC with home stretching is associated with greater changes in spasticity than usual care (UC), consisting of an illustrated stretching booklet and home stretching but without group instruction or support, in people with MS. Methods Ambulatory MS patients with self-reported spasticity interfering with daily activities were randomized to STC or UC. Individuals completed questionnaires regarding MS, spasticity, walking, fatigue and mood, and physical measures of spasticity and walking. Results Thirty-eight of 40 participants completed both assessments. Mean total score and scores on two subscales of the MS Spasticity Scale-88 improved more with STC than with UC (p spasticity more than UC and provided encouraging improvements in other measures. PMID:28607753

  11. Access to medical care among persons with musculoskeletal conditions. A study using a random sample of households in San Mateo County, California.

    Science.gov (United States)

    Yelin, E; Bernhard, G; Pflugrad, D

    1995-08-01

    To study access to medical care services, including subspecialty care, among persons with musculoskeletal conditions. In early 1993, a random sample of households in San Mateo County, California, was screened for the presence of household members with musculoskeletal conditions, and a member of each household so identified was administered a structured survey about access to medical care and other related subjects. Eighty-six percent of all persons with a musculoskeletal condition had ever seen at least one physician for the condition, but only 6.5% had ever seen a rheumatologist. Those without health insurance were only 82% as likely as those with health insurance to have ever seen a physician. Most persons with a musculoskeletal condition have seen a physician for the condition, but lack of health insurance significantly reduces the proportion who have done so.

  12. Development and comparison of algorithms for generating a scan sequence for a random access scanner. [ZAP (and flow charts for ZIP and SCAN), in FORTRAN for DEC-10

    Energy Technology Data Exchange (ETDEWEB)

    Eason, R. O.

    1980-09-01

    Many data acquisition systems incorporate high-speed scanners to convert analog signals into digital format for further processing. Some systems multiplex many channels into a single scanner. A random access scanner whose scan sequence is specified by a table in random access memory will permit different scan rates on different channels. Generation of this scan table can be a tedious manual task when there are many channels (e.g. 50), when there are more than a few scan rates (e.g. 5), and/or when the ratio of the highest scan rate to the lowest scan rate becomes large (e.g. 100:1). An algorithm is developed which will generate these scan sequences for the random access scanner and implements the algorithm on a digital computer. Application of number theory to the mathematical statement of the problem led to development of several algorithms which were implemented in FORTRAN. The most efficient of these algorithms operates by partitioning the problem into a set of subproblems. Through recursion they solve each subproblem by partitioning it repeatedly into even smaller parts, continuing until a set of simple problems is created. From this process, a pictorial representation or wheel diagram of the problem can be constructed. From the wheel diagram and a description of the original problem, a scan table can be constructed. In addition, the wheel diagram can be used as a method of storing the scan sequence in a smaller amount of memory. The most efficient partitioning algorithm solved most scan table problems in less than a second of CPU time. Some types of problems, however, required as much as a few minutes of CPU time. 26 figures, 2 tables.

  13. Community Impact of Pharmacy-Randomized Intervention to Improve Access to Syringes and Services for Injection Drug Users

    Science.gov (United States)

    Crawford, Natalie D.; Amesty, Silvia; Rivera, Alexis V.; Harripersaud, Katherine; Turner, Alezandria; Fuller, Crystal M.

    2014-01-01

    Objectives: In an effort to reduce HIV transmission among injection drug users (IDUs), New York State deregulated pharmacy syringe sales in 2001 through the Expanded Syringe Access Program by removing the requirement of a prescription. With evidence suggesting pharmacists' ability to expand their public health role, a structural, pharmacy-based…

  14. A Randomized Controlled Trial of a Mobile Clinical Decision Aid to Improve Access to Kidney Transplantation: iChoose Kidney

    Directory of Open Access Journals (Sweden)

    Rachel E. Patzer

    2016-05-01

    Discussion: Engaging patients in health care choices can increase patient empowerment and improve knowledge and understanding of treatment choices. If the effectiveness of iChoose Kidney has a greater impact on patients with low health literacy, lower socioeconomic status, and minority race, this decision aid could help reduce disparities in access to kidney transplantation.

  15. The supply voltage scaled dependency of the recovery of single event upset in advanced complementary metal—oxide—semiconductor static random-access memory cells

    Science.gov (United States)

    Li, Da-Wei; Qin, Jun-Rui; Chen, Shu-Ming

    2013-02-01

    Using computer-aided design three-dimensional simulation technology, the supply voltage scaled dependency of the recovery of single event upset and charge collection in static random-access memory cells are investigated. It reveals that the recovery linear energy transfer threshold decreases with the supply voltage reducing, which is quite attractive for dynamic voltage scaling and subthreshold circuit radiation-hardened design. Additionally, the effect of supply voltage on charge collection is also investigated. It is concluded that the supply voltage mainly affects the bipolar gain of the parasitical bipolar junction transistor (BJT) and the existence of the source plays an important role in supply voltage variation.

  16. A randomized phase 3 study on the effect of thalidomide combined with adriamycin, dexamethasone, and high-dose melphalan, followed by thalidomide maintenance in patients with multiple myeloma.

    NARCIS (Netherlands)

    Lokhorst, H.M.; Holt, B. van der; Zweegman, S.; Vellenga, E.; Croockewit, S.; Oers, M.H. van; Borne, P. von dem; Wijermans, P.; Schaafsma, R.; Weerdt, O. de; Wittebol, S.; Delforge, M.; Berenschot, H.; Bos, G.M.; Jie, K.S.; Sinnige, H.; Marwijk-Kooy, M. van; Joosten, P.; Minnema, M.C.; Ammerlaan, R. van; Sonneveld, P.

    2010-01-01

    The phase 3 trial HOVON-50 was designed to evaluate the effect of thalidomide during induction treatment and as maintenance in patients with multiple myeloma who were transplant candidates. A total of 556 patients was randomly assigned to arm A: 3 cycles of vincristine, adriamycin, and

  17. A randomized phase 3 study on the effect of thalidomide combined with adriamycin, dexamethasone, and high-dose melphalan, followed by thalidomide maintenance in patients with multiple myeloma

    NARCIS (Netherlands)

    Lokhorst, Henk M.; van der Holt, Bronno; Zweegman, Sonja; Vellenga, Edo; Croockewit, Sandra; van Oers, Marinus H.; von dem Borne, Peter; Wijermans, Pierre; Schaafsma, Ron; de Weerdt, Okke; Wittebol, Shulamiet; Delforge, Michel; Berenschot, Henriëtte; Bos, Gerard M.; Jie, Kon-Siong G.; Sinnige, Harm; van Marwijk-Kooy, Marinus; Joosten, Peter; Minnema, Monique C.; van Ammerlaan, Rianne; Sonneveld, Pieter

    2010-01-01

    The phase 3 trial HOVON-50 was designed to evaluate the effect of thalidomide during induction treatment and as maintenance in patients with multiple myeloma who were transplant candidates. A total of 556 patients was randomly assigned to arm A: 3 cycles of vincristine, adriamycin, and

  18. Correction to: Impact of an electronic monitoring device and behavioural feedback on adherence to multiple sclerosis therapies in youth: results of a randomized trial.

    Science.gov (United States)

    Yeh, E Ann; Grover, Stephanie A; Powell, Victoria E; Alper, Gulay; Banwell, Brenda L; Edwards, Kim; Gorman, Mark; Graves, Jennifer; Lotze, Timothy E; Mah, Jean K; Mednick, Lauren; Ness, Jayne; Obadia, Maya; Slater, Ruth; Waldman, Amy; Waubant, Emmanuelle; Schwartz, Carolyn E

    2017-12-23

    The clinicaltrials.gov identifying number for the article titled "Impact of an electronic monitoring device and behavioral feedback on adherence to multiple sclerosis therapies in youth: results of a randomized trial" is NCT02234713 (https://clinicaltrials.gov/ct2/show/NCT02234713).

  19. A randomized phase 3 study on the effect of thalidomide combined with adriamycin, dexamethasone, and high-dose melphalan, followed by thalidomide maintenance in patients with multiple myeloma

    NARCIS (Netherlands)

    H.M. Lokhorst (Henk); B. van der Holt (Bronno); S. Zweegman (Sonja); E. Vellenga (Edo); S. Croockewit (Sandra); M.H.J. van Oers (Marinus); P.A. von dem Borne (P. A.); P.W. Wijermans (Pierre); R. Schaafsma (Ron); O. de Weerdt (Okke); S. Wittebol (Shulamit); M. Delforge (Michel); H. Berenschot (Henriëtte); G.M. Bos (Gerard); K.S-G. Jie; H. Sinnige (Harm); M. van Marwijk Kooy (Marinus); P. Joosten (Peter); M.C. Minnema (Monique); R.A.H.M. Ammerlaan (Rianne); P. Sonneveld (Pieter)

    2010-01-01

    textabstractThe phase 3 trial HOVON-50 was designed to evaluate the effect of thalidomide during induction treatment and as maintenance in patients with multiple myeloma who were transplant candidates. A total of 556 patients was randomly assigned to arm A: 3 cycles of vincristine, adriamycin, and

  20. Non-Orthogonal Multiple Access and Carrierless Amplitude Phase Modulation for Flexible Multi-User Provisioning in 5G Mobile Networks

    DEFF Research Database (Denmark)

    Rommel, Simon; Altabas, Jose Antonio; Puerta Ramírez, Rafael

    2017-01-01

    In this paper, a combined non-orthogonal multiple access (NOMA) and multiband carrierless amplitude phase modulation (multiCAP) scheme is proposed for capacity enhancement of and flexible resource provisioning in 5G mobile networks. The proposed scheme is experimentally evaluated over a W......-band millimeter wave radio-over fiber system. The evaluated NOMACAP system consists of six 1.25 GHz multiCAP bands and two NOMA levels with quadrature phase shift keying and can provide an aggregated transmission rate of 30 Gbit/s. The proposed system can dynamically adapt to different user densities and data...

  1. A random matrix approach to detect defects in a strongly scattering polycrystal: How the memory effect can help overcome multiple scattering

    Science.gov (United States)

    Shahjahan, S.; Aubry, A.; Rupin, F.; Chassignole, B.; Derode, A.

    2014-06-01

    We report on ultrasonic imaging in a random heterogeneous medium. The goal is to detect flaws embedded deeply into a polycrystalline material. A 64-element array of piezoelectric transmitters/receivers at a central frequency of 5 MHz is used to capture the Green's matrix in a backscattering configuration. Because of multiple scattering, conventional imaging completely fails to detect the deepest flaws. We utilize a random matrix approach, taking advantage of the deterministic coherence of the backscattered wave-field which is characteristic of single scattering and related to the memory effect. This allows us to separate single and multiple scattering contributions. As a consequence, we show that flaws are detected beyond the conventional limit, as if multiple scattering had been overcome.

  2. Towards a physiological signal-based access solution for a non-verbal adolescent with severe and multiple disabilities.

    Science.gov (United States)

    Memarian, Negar; Blain-Moraes, Stefanie; Chau, Tom

    2014-08-01

    To find physiologically arousing stimuli and labile physiological channels in a non-verbal adolescent with severe and multiple congenital disabilities, who did not have a reliable means of communication. The client was repeatedly presented with visual and audiovisual stimuli, representing variations of six contextual factors over three sessions in a one month period. For each stimulus, reactions were detected in the client's four peripheral autonomic nervous system signals using a rule-based classification algorithm. During the presentation of audiovisual stimuli, the number of physiological reactions significantly differed from that observed in baseline (χ(2) = 3.93, p = 0.0476). Aural stimuli articulated in an unfamiliar voice, and aural stimuli containing anticipatory patterns were also physiologically arousing. Fingertip temperature was the client's most labile physiological signal. The results of this case study suggest that physiological data may complement caregiver acumen in deciphering the reactions of non-verbal clients with severe and multiple disabilities.

  3. Effect of multiple micronutrient supplementation on survival of HIV-infected children in Uganda: a randomized, controlled trial.

    Science.gov (United States)

    Ndeezi, Grace; Tylleskär, Thorkild; Ndugwa, Christopher M; Tumwine, James K

    2010-06-03

    Micronutrient deficiencies compromise the survival of HIV-infected children in low-income countries. We assessed the effect of multiple micronutrient supplementation on the mortality of HIV-infected children in Uganda. In a randomized, controlled trial, 847 children aged one to five years and attending HIV clinics in Uganda were stratified by antiretroviral therapy (ART, n = 85 versus no ART, n = 762). The children were randomized to six months of either: twice the recommended dietary allowance of 14 micronutrients as the intervention arm (vitamins A, B1, B2, niacin, B6, B12, C, D and E, folate, zinc, copper, iodine and selenium); or the standard recommended dietary allowance of six multivitamins (vitamins A, D2, B1, B2, C and niacin) as a comparative "standard-of-care" arm. Mortality was analyzed at 12 months of follow up using Kaplan Meier curves and the log rank test. Mortality at 12 months was 25 out of 426 (5.9%) children in the intervention arm and 28 out of 421 (6.7%) in the comparative arms: risk ratio 0.9 (95% CI 0.5 - 1.5). Two out of 85 (2.4%) children in the ART stratum died compared with 51 out of 762 (6.7%) in the non-ART stratum. Of those who died in the non-ART stratum, 25 of 383 (6.5%) were in the intervention arm and 26 of 379 (6.9%) in the comparative arm; risk ratio 1.0 (95% CI 0.6 - 1.6). There was no significant difference in survival at 12 months (p = 0.64, log rank test). In addition, there was no significant difference in mean weight-for-height at 12 months; 0.70 +/- 1.43 (95% CI 0.52 - 0.88) for the intervention versus 0.59 +/- 1.15 (95% CI 0.45 - 0.75) in the comparative arm. The mean CD4 cell count; 1024 +/- 592 (95% CI 942 - 1107) versus 1060 +/- 553 (95% CI 985 - 1136) was also similar between the two groups. Twice the recommended dietary allowance of 14 micronutrients compared with a standard recommended dietary allowance of six multivitamins for six months was well tolerated, but it did not significantly alter mortality, growth or CD

  4. Randomized controlled trial of an e-learning designed behavioral intervention for increasing physical activity behavior in multiple sclerosis.

    Science.gov (United States)

    Motl, Robert W; Hubbard, Elizabeth A; Bollaert, Rachel E; Adamson, Brynn C; Kinnett-Hopkins, Dominique; Balto, Julia M; Sommer, Sarah K; Pilutti, Lara A; McAuley, Edward

    2017-01-01

    Internet-delivered, behavioral interventions represent a cost-effective, broadly disseminable approach for teaching persons with multiple sclerosis (MS) the theory-based skills, techniques, and strategies for changing physical activity. This pilot, randomized controlled trial examined the efficacy of a newly developed Internet website based on e-learning approaches that delivered a theory-based behavior intervention for increasing physical activity and improving symptoms, walking impairment, and neurological disability. Participants with MS (N = 47) were randomly assigned into behavioral intervention (n = 23) or waitlist control (n = 24) conditions delivered over a six-month period. Outcomes were administered before and after the six-month period using blinded assessors, and data were analyzed using analysis of covariance in SPSS. There was a significant, positive intervention effect on self-reported physical activity (P = 0.05, [Formula: see text] = 0.10), and non-significant improvement in objectively measured physical activity (P = 0.24, [Formula: see text] = 0.04). There were significant, positive effects of the intervention on overall (P = 0.018, [Formula: see text] = 0.13) and physical impact of fatigue (P = 0.003, [Formula: see text] = 0.20), self-reported walking impairment (P = 0.047, [Formula: see text] = 0.10), and disability status (P = 0.033, [Formula: see text] = 0.11). There were non-significant improvements in fatigue severity (P = 0.10, [Formula: see text] = 0.06), depression (P = 0.10, [Formula: see text] = 0.07) and anxiety (P = 0.06, [Formula: see text] = 0.09) symptoms, and self-reported disability (P = 0.10, [Formula: see text] = 0.07). We provide evidence for the efficacy of an Internet-based behavioral intervention with content delivered through interactive video courses grounded in e-learning principles for increasing physical activity and possibly

  5. Complementary, Alternative, and Mainstream Service use Among Families with Young Children with Multiple Disabilities: Family Costs to Access Choices.

    Science.gov (United States)

    Bourke-Taylor, Helen; Cotter, Claire; Stephan, Rebecca

    2014-11-03

    ABSTRACT Families raising a young child with multiple disabilities are charged with significant responsibilities such as learning about their child's condition and navigating mainstream and alternative services. Aim: Describe service choices, costs, out of pocket expenses, and the impact on families. Methods: Survey design using a custom questionnaire was used to collect extensive retrospective and current data. Purposive sampling (N = 29) occurred from one early intervention facility specialized in servicing children with cerebral palsy (CP) and, or multiple disabilities in Australia. Descriptive statistics were used for analysis of data. Results: Twenty-three (79%) families reported caring for a child with CP. Twenty-three families reported using at least one complementary/alternative intervention. Out-of-pocket amounts were reported including: chiropractic services (10 families); naturopathy (9 families); point percussion therapy (7 families), and Chinese medicine (6 families). Expenses resulted in families reporting forgoing clothing items, family entertainment, recreation/hobbies for parents (55%); family holidays (59%); time for parents alone (66%); and health services for parents (38%). Conclusions: Families of young children with multiple disabilities select a wide range of services for their child, with consequential out of pocket expenses. Early intervention professionals can be an important resource for families as they evaluate their choices and select interventions for their child.

  6. Effects of Prenatal Multiple Micronutrient Supplementation on Fetal Growth Factors: A Cluster-Randomized, Controlled Trial in Rural Bangladesh

    Science.gov (United States)

    Gernand, Alison D.; Schulze, Kerry J.; Nanayakkara-Bind, Ashika; Arguello, Margia; Shamim, Abu Ahmed; Ali, Hasmot; Wu, Lee; West, Keith P.; Christian, Parul

    2015-01-01

    Prenatal multiple micronutrient (MM) supplementation improves birth weight through increased fetal growth and gestational age, but whether maternal or fetal growth factors are involved is unclear. Our objective was to examine the effect of prenatal MM supplementation on intrauterine growth factors and the associations between growth factors and birth outcomes in a rural setting in Bangladesh. In a double-blind, cluster-randomized, controlled trial of MM vs. iron and folic acid (IFA) supplementation, we measured placental growth hormone (PGH) at 10 weeks and PGH and human placental lactogen (hPL) at 32 weeks gestation in maternal plasma (n = 396) and insulin, insulin-like growth factor-1 (IGF-1), and IGF binding protein-1 (IGFBP-1) in cord plasma (n = 325). Birth size and gestational age were also assessed. Early pregnancy mean (SD) BMI was 19.5 (2.4) kg/m2 and birth weight was 2.68 (0.41) kg. There was no effect of MM on concentrations of maternal hPL or PGH, or cord insulin, IGF-1, or IGFBP-1. However, among pregnancies of female offspring, hPL concentration was higher by 1.1 mg/L in the third trimester (95% CI: 0.2, 2.0 mg/L; p = 0.09 for interaction); and among women with height supplementation had no overall impact on intrauterine growth factors. MM supplementation altered some growth factors differentially by maternal early pregnancy nutritional status and sex of the offspring, but this should be examined in other studies. Trial Registration ClinicalTrials.gov NCT00860470 PMID:26431336

  7. Consistency of eletriptan in treating migraine: Results of a randomized, within-patient multiple-dose study.

    Science.gov (United States)

    Almas, Mary; Tepper, Stewart J; Landy, Stephen; Schweizer, Edward; Ramos, Elodie

    2014-02-01

    The current study evaluated the consistency of eletriptan response. Using a within-patient crossover design, patients with migraine completed a three-attack, open-label, lead-in period, before being treated, double-blind for four attacks, with either eletriptan 40 mg (ELE-40; N = 539) or eletriptan 80 mg (ELE-80; N = 432); placebo was randomly substituted for the treatment of one attack. On an A PRIORI analysis of within-patient consistency, double-blind treatment was associated with similar 2 hour headache response rates using a ≥2/3 response criterion for ELE-40 (77%) and ELE-80 (73%), and using a 3/3 response criterion for ELE-40 (46%) and ELE-80 (47%). Within-patient consistency in achieving pain-free status at 2 hours using a ≥2/3 criterion was slightly higher on ELE-40 (42%) compared with ELE-80 (38%), and was similar using the 3/3 criterion (18% on ELE-40, 17% on ELE-80). On a repeated measures logistic regression analysis across all treated attacks, the probability of achieving a headache response at 2 hours ranged from 71% to 74% on ELE-40 vs. 17% to 28% on placebo ( P ELE-80 vs. 21% to 27% on placebo ( P ELE-40 and ELE-80. Few adverse events occurred with incidence ≥10% on ELE-40 (asthenia, 5.0%) or ELE-80 (asthenia, 10%; nausea, 5.8%). Discontinuations because of adverse events were 0.2% on ELE-40, and 1.6% on ELE-80 CONCLUSION: In this multiple attack study, eletriptan was well-tolerated and demonstrated consistent and significant efficacy in the treatment of migraine.

  8. Randomized phase 1b trial of MOR103, a human antibody to GM-CSF, in multiple sclerosis.

    Science.gov (United States)

    Constantinescu, Cris S; Asher, Aliya; Fryze, Waldemar; Kozubski, Wojciech; Wagner, Frank; Aram, Jehan; Tanasescu, Radu; Korolkiewicz, Roman P; Dirnberger-Hertweck, Maren; Steidl, Stefan; Libretto, Susan E; Sprenger, Till; Radue, Ernst W

    2015-08-01

    To determine the safety, pharmacokinetics (PK), and immunogenicity of the recombinant human monoclonal antibody MOR103 to granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients with multiple sclerosis (MS) with clinical or MRI activity. In this 20-week, randomized, double-blind, placebo-controlled phase 1b dose-escalation trial (registration number NCT01517282), adults with relapsing-remitting MS (RRMS) or secondary progressive MS (SPMS) received an IV infusion of placebo (n = 6) or MOR103 0.5 (n = 8), 1.0 (n = 8), or 2.0 (n = 9) mg/kg every 2 weeks for 10 weeks. Patients had to have ≤10 gadolinium (Gd)-enhancing brain lesions on T1-weighted MRI at baseline. The primary objective was safety. Most treatment-emergent adverse events (TEAEs) were mild to moderate in severity. The most frequent was nasopharyngitis. Between-group differences in TEAE numbers were small. There were no TEAE-related trial discontinuations, infusion-related reactions, or deaths. Nine patients experienced MS exacerbations: 3, 5, 1, and 0 patient(s) in the placebo, 0.5, 1.0, and 2.0 mg/kg groups, respectively. A few T1 Gd-enhancing lesions and/or new or enlarging T2 lesions indicative of inflammation were observed in all treatment groups. No clinically significant changes were observed in other clinical assessments or laboratory safety assessments. No anti-MOR103 antibodies were detected. PK evaluations indicated dose linearity with low/no drug accumulation over time. MOR103 was generally well-tolerated in patients with RRMS or SPMS. No evidence of immunogenicity was found. This phase 1b study provides Class I evidence that MOR103 has acceptable tolerability in patients with MS.

  9. Experimental protocol of a randomized controlled clinical trial investigating exercise, subclinical atherosclerosis, and walking mobility in persons with multiple sclerosis.

    Science.gov (United States)

    Griffith, Garett; Klaren, Rachel E; Motl, Robert W; Baynard, Tracy; Fernhall, Bo

    2015-03-01

    This randomized controlled trial (RCT) will investigate the effects of a home-based aerobic exercise training regimen (i.e., cycle ergometry) on subclinical atherosclerosis and walking mobility in persons with multiple sclerosis (MS) and minimal disability. This RCT will recruit 54 men and women who have an Expanded Disability Status Scale characteristic of the 1st stage of MS (i.e., 0-4.0) to participate in a 3 month exercise or stretching intervention, with assessments of subclinical atherosclerosis and walking mobility conducted at baseline, week 6 (midpoint), and week 12 (conclusion) of the program. The exercise intervention will consist of 3 days/week of cycling, with a gradual increase of duration followed by an increase in intensity across the 3 month period. The attention-control condition will incorporate stretching activities and will require the same contact time commitment as the exercise condition. Both study groups will participate in weekly video chat sessions with study personnel in order to monitor and track program adherence. Primary outcomes will consist of assessments of vascular structure and function, as well as several walking tasks. Additional outcomes will include questionnaires, cardiorespiratory fitness assessment, and a 1-week free-living physical activity assessment. This investigation will increase understanding of the role of aerobic exercise as part of a treatment plan for managing subclinical atherosclerosis and improving walking mobility persons in the 1st stage of MS. Overall, this study design has the potential to lead to effective aerobic exercise intervention strategies for this population and improve program adherence. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Zoledronic acid as compared with observation in multiple myeloma patients at biochemical relapse: results of the randomized AZABACHE Spanish trial.

    Science.gov (United States)

    García-Sanz, Ramón; Oriol, Albert; Moreno, María J; de la Rubia, Javier; Payer, Angel R; Hernández, Miguel T; Palomera, Luis; Teruel, Ana I; Blanchard, María J; Gironella, Mercedes; Ribas, Paz; Bargay, Joan; Abellá, Eugenia; Granell, Miquel; Ocio, Enrique M; Ribera, Josep M; San Miguel, Jesús F; Mateos, María V

    2015-09-01

    This study analyzed the anti-myeloma effect of zoledronic acid monotherapy by investigating patients at the time of asymptomatic biochemical relapse. One hundred patients were randomized to receive either zoledronic acid (4 mg iv/4 weeks, 12 doses) (n=51) or not (n=49). Experimental and control groups were well balanced for disease and prognostic features. Zoledronic acid did not show an antitumor effect according to changes in M-component. However, there were fewer symptomatic progressions in the experimental group than in the control group (34 versus 41, respectively; P=0.05) resulting in a median time to symptoms of 16 versus 10 months (P=0.161). The median time to next therapy was also slightly longer for the treated group than the untreated, control group (13.4 versus 10.1 months), although the difference was not statistically significant (P=0.360). The pattern of relapses was different for treated versus control patients: progressive bone disease (8 versus 20), anemia (24 versus 18), renal dysfunction (1 versus 2), and plasmacytomas (1 versus 1, respectively). This concurred with fewer skeletal-related events in the treated group than in the control group (2 versus 14), with a projected 4-year event proportion of 6% versus 40% (P<0.001). In summary, zoledronic acid monotherapy does not show an antitumor effect on biochemical relapses in multiple myeloma, but does reduce the risk of progression with symptomatic bone disease and skeletal complications. This trial was registered in the ClinicalTrials.gov database with code NCT01087008. Copyright© Ferrata Storti Foundation.

  11. Computed tomography synthesis from magnetic resonance images in the pelvis using multiple random forests and auto-context features

    Science.gov (United States)

    Andreasen, Daniel; Edmund, Jens M.; Zografos, Vasileios; Menze, Bjoern H.; Van Leemput, Koen

    2016-03-01

    In radiotherapy treatment planning that is only based on magnetic resonance imaging (MRI), the electron density information usually obtained from computed tomography (CT) must be derived from the MRI by synthesizing a so-called pseudo CT (pCT). This is a non-trivial task since MRI intensities are neither uniquely nor quantitatively related to electron density. Typical approaches involve either a classification or regression model requiring specialized MRI sequences to solve intensity ambiguities, or an atlas-based model necessitating multiple registrations between atlases and subject scans. In this work, we explore a machine learning approach for creating a pCT of the pelvic region from conventional MRI sequences without using atlases. We use a random forest provided with information about local texture, edges and spatial features derived from the MRI. This helps to solve intensity ambiguities. Furthermore, we use the concept of auto-context by sequentially training a number of classification forests to create and improve context features, which are finally used to train a regression forest for pCT prediction. We evaluate the pCT quality in terms of the voxel-wise error and the radiologic accuracy as measured by water-equivalent path lengths. We compare the performance of our method against two baseline pCT strategies, which either set all MRI voxels in the subject equal to the CT value of water, or in addition transfer the bone volume from the real CT. We show an improved performance compared to both baseline pCTs suggesting that our method may be useful for MRI-only radiotherapy.

  12. Use of videotape to assess mobility in a controlled randomized crossover trial of physiotherapy in chronic multiple sclerosis.

    Science.gov (United States)

    Wiles, C M; Newcombe, R G; Fuller, K J; Jones, A; Price, M

    2003-05-01

    To determine to what degree assessment of mobility based on comparison of videotape recordings before and after courses of physiotherapy in patients with chronic multiple sclerosis (MS) is reliable, correlates with 'live' assessments and indicates benefit. Prospective data collection within a randomized crossover controlled trial of physiotherapy at home, as an outpatient, or 'no therapy' in 40 patients. Hospital outpatients: outpatient and home physiotherapy. Mobility change based on a comparison of short video recordings before and after each treatment period was scored independently by two physiotherapists blinded to therapy type and other measures of outcome. Scores were compared with changes in the Rivermead Mobility Index (RMI) and other indices assessed by a physiotherapist in the patient's home. The two video observers agreed substantially on patient outcome. Changes in walking based on video correlated with RMI for home treatment (r = 0.41, p = 0.008) but not for hospital or no treatment periods (r = 0.14 and 0.15): video changes correlated with the 'live' assessor's global change score inconsistently ('no therapy' r = 0.48, p = 0.002, hospital r = 0.30, p = 0.06 and home r = 0.17, p = 0.30 treatment periods). Based on video data alone, improved mobility was evident following home therapy for only one observer but not for the other or the averaged scores of both. There was substantial agreement between two observers deciding on change in mobility based on independent blinded evaluation of short video sequences. However the correlations of these with 'live' assessments were variable. Physiotherapy had a less clear benefit on mobility based on video analysis alone compared with 'live' assessments. The study highlights the need for more objective measures of habitual mobility over longer periods.

  13. Cross-Layer Design of an Energy-Efficient Cluster Formation Algorithm with Carrier-Sensing Multiple Access for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Buratti Chiara

    2005-01-01

    Full Text Available A new energy-efficient scheme for data transmission in a wireless sensor network (WSN is proposed, having in mind a typical application including a sink, which periodically triggers the WSN, and nodes uniformly distributed over a specified area. Routing, multiple access control (MAC, physical, energy, and propagation aspects are jointly taken into account through simulation; however, the protocol design is based on some analytical considerations reported in the appendix. Information routing is based on a clustered self-organized structure; a carrier-sensing multiple access (CSMA protocol is chosen at MAC layer. Two different scenarios are examined, characterized by different channel fading rates. Four versions of our protocol are presented, suitably oriented to the two different scenarios; two of them implement a cross-layer (CL approach, where MAC parameters influence both the network and physical layers. Performance is measured in terms of network lifetime (related to energy efficiency and packet loss rate (related to network availability. The paper discusses the rationale behind the selection of MAC protocols for WSNs and provides a complete model characterization spanning from the network layer to the propagation channel. The advantages of the CL approach, with respect to an algorithm which belongs to the well-known class of low-energy adaptive clustering hierarchy (LEACH protocols, are shown.

  14. On the capacity of multiple access and broadcast fading Channels with full channel state information at low power regime

    KAUST Repository

    Rezki, Zouheir

    2013-07-01

    We study the throughput capacity region of the Gaussian multi-access (MAC) fading channel with perfect channel state information (CSI) at the receiver and at the transmitters (CSI-TR), at low power regime. We show that it has a multidimensional rectangle structure and thus is simply characterized by single user capacity points. More specifically, we show that at low power regime, the boundary surface of the capacity region shrinks to a single point corresponding to the sum-rate maximizer and that the coordinates of this point coincide with single user capacity bounds. Using the duality of Gaussian MAC and broadcast channels (BC), we provide a simple characterization of the BC capacity region at low power regime. © 2013 IEEE.

  15. Power reduction by power gating in differential pair type spin-transfer-torque magnetic random access memories for low-power nonvolatile cache memories

    Science.gov (United States)

    Ohsawa, Takashi; Ikeda, Shoji; Hanyu, Takahiro; Ohno, Hideo; Endoh, Tetsuo

    2014-01-01

    Array operation currents in spin-transfer-torque magnetic random access memories (STT-MRAMs) that use four differential pair type magnetic tunnel junction (MTJ)-based memory cells (4T2MTJ, two 6T2MTJs and 8T2MTJ) are simulated and compared with that in SRAM. With L3 cache applications in mind, it is assumed that the memories are composed of 32 Mbyte capacity to be accessed in 64 byte in parallel. All the STT-MRAMs except for the 8T2MTJ one are designed with 32 bit fine-grained power gating scheme applied to eliminate static currents in the memory cells that are not accessed. The 8T2MTJ STT-MRAM, the cell’s design concept being not suitable for the fine-grained power gating, loads and saves 32 Mbyte data in 64 Mbyte unit per 1 Mbit sub-array in 2 × 103 cycles. It is shown that the array operation current of the 4T2MTJ STT-MRAM is 70 mA averaged in 15 ns write cycles at Vdd = 0.9 V. This is the smallest among the STT-MRAMs, about the half of the low standby power (LSTP) SRAM whose array operation current is totally dominated by the cells’ subthreshold leakage.

  16. Holding personal information in a disease-specific register: the perspectives of people with multiple sclerosis and professionals on consent and access.

    Science.gov (United States)

    Baird, W; Jackson, R; Ford, H; Evangelou, N; Busby, M; Bull, P; Zajicek, J

    2009-02-01

    To determine the views of people with multiple sclerosis (MS) and professionals in relation to confidentiality, consent and access to data within a proposed MS register in the UK. Qualitative study using focus groups (10) and interviews (13). England and Northern Ireland. 68 people with MS, neurologists, MS nurses, health services management professionals, researchers, representatives from pharmaceutical companies and social care professionals. People with MS expressed open and altruistic views towards the use of their personal information to facilitate service provision and research, placing trust in responsible guardianship and legitimate use of their information. Participant's proposed that people with MS should be able to select their individual level of involvement in a register using levels of consent. It was agreed that access to the register should be governed by a guardianship committee composed of a range of stakeholders. People with MS did not wish their details to be used by marketing agencies and did not consider this a legitimate use of their data. Whilst participants were positive of the role a register could play in promoting research, participants felt that access to data by pharmaceutical industries should be administered by the guardianship committee. People with MS are concerned should their employers be able to access their personal information. Professionals were more cautious than people with MS in their approach to the use of patient personal data within a register. Whilst all stakeholders were positive of the benefits of an MS register, development of such a resource must incorporate robust data security and guardianship measures in order to ensure that, whilst opportunities are maximised, risks to the privacy of individuals and legal challenges to professionals are avoided.

  17. Glatiramer Acetate and Nanny Proteins Restrict Access of the Multiple Sclerosis Autoantigen Myelin Basic Protein to the 26S Proteasome

    Directory of Open Access Journals (Sweden)

    Ekaterina Kuzina

    2014-01-01

    Full Text Available We recently showed that myelin basic protein (MBP is hydrolyzed by 26S proteasome without ubiquitination. The previously suggested concept of charge-mediated interaction between MBP and the proteasome led us to attempt to compensate or mimic its positive charge to inhibit proteasomal degradation. We demonstrated that negatively charged actin and calmodulin (CaM, as well as basic histone H1.3, inhibit MBP hydrolysis by competing with the proteasome and MBP, respectively, for binding their counterpart. Interestingly, glatiramer acetate (GA, which is used to treat multiple sclerosis (MS and is structurally similar to MBP, inhibits intracellular and in vitro proteasome-mediated MBP degradation. Therefore, the data reported in this study may be important for myelin biogenesis in both the normal state and pathophysiological conditions.

  18. GSR-TDMA: A Geometric Spatial Reuse-Time Division Multiple Access MAC Protocol for Multihop Underwater Acoustic Sensor Networks

    Directory of Open Access Journals (Sweden)

    Changho Yun

    2016-01-01

    Full Text Available The nonnegligible propagation delay of acoustic signals causes spatiotemporal uncertainty that occasionally enables simultaneous, collision-free packet transmission among underwater nodes (UNs. These transmissions can be handled by efficiently managing the channel access of the UNs in the data-link layer. To this end, Geometric Spatial Reuse-TDMA (GSR-TDMA, a new TDMA-based MAC protocol, is designed for use in centralized, multihop underwater acoustic sensor networks (UASNs, and in this case all UNs are periodically scheduled after determining a geometric map according to the information on their location. The scheduling strategy increases the number of UNs that send packets coincidentally via two subscheduling configurations (i.e., interhop and intrahop scheduling. Extensive simulations are used to investigate the reception success rate (RSR and the multihop delay (MHD of GSR-TDMA, and the results are compared to those of previous approaches, including C-MAC and HSR-TDMA. GSR-TDMA outperforms C-MAC; the RSR of GSR-TDMA is 15% higher than that of C-MAC, and the MHD of GSR-TDMA is 30% lower than that of C-MAC at the most. In addition, GSR-TDMA provides even better performance improvements over HSR-TDMA; the RSR of GSR-TDMA is 50% higher than that of HSR-TDMA, and the MHD of GSR-TDMA is an order of 102 lower than that of HSR-TDMA at the most.

  19. On the capacity of multiple access and broadcast fading channels with full channel state information at low SNR

    KAUST Repository

    Rezki, Zouheir

    2014-01-01

    We study the throughput capacity region of the Gaussian multi-access (MAC) fading channel with perfect channel state information (CSI) at the receiver and at the transmitters, at low power regime. We show that it has a multidimensional rectangle structure and thus is simply characterized by single user capacity points.More specifically, we show that at low power regime, the boundary surface of the capacity region shrinks to a single point corresponding to the sum rate maximizer and that the coordinates of this point coincide with single user capacity bounds. Inspired from this result, we propose an on-off scheme, compute its achievable rate, and show that this scheme achieves single user capacity bounds of the MAC channel for a wide class of fading channels at asymptotically low power regime. We argue that this class of fading encompasses all known wireless channels for which the capacity region of the MAC channel has even a simpler expression in terms of users\\' average power constraints only. Using the duality of Gaussian MAC and broadcast channels (BC), we deduce a simple characterization of the BC capacity region at low power regime and show that for a class of fading channels (including Rayleigh fading), time-sharing is asymptotically optimal. © 2014 IEEE.

  20. A model for Intelligent Random Access Memory architecture (IRAM) cellular automata algorithms on the Associative String Processing machine (ASTRA)

    CERN Document Server

    Rohrbach, F; Vesztergombi, G

    1997-01-01

    In the near future, the computer performance will be completely determined by how long it takes to access memory. There are bottle-necks in memory latency and memory-to processor interface bandwidth. The IRAM initiative could be the answer by putting Processor-In-Memory (PIM). Starting from the massively parallel processing concept, one reached a similar conclusion. The MPPC (Massively Parallel Processing Collaboration) project and the 8K processor ASTRA machine (Associative String Test bench for Research \\& Applications) developed at CERN \\cite{kuala} can be regarded as a forerunner of the IRAM concept. The computing power of the ASTRA machine, regarded as an IRAM with 64 one-bit processors on a 64$\\times$64 bit-matrix memory chip machine, has been demonstrated by running statistical physics algorithms: one-dimensional stochastic cellular automata, as a simple model for dynamical phase transitions. As a relevant result for physics, the damage spreading of this model has been investigated.

  1. Coherent light scattering of heterogeneous randomly rough films and effective medium in the theory of electromagnetic wave multiple scattering

    Energy Technology Data Exchange (ETDEWEB)

    Berginc, G [THALES, 2 avenue Gay-Lussac 78995 ELANCOURT (France)

    2013-11-30

    We have developed a general formalism based on Green's functions to calculate the coherent electromagnetic field scattered by a random medium with rough boundaries. The approximate expression derived makes it possible to determine the effective permittivity, which is generalised for a layer of an inhomogeneous random medium with different types of particles and bounded with randomly rough interfaces. This effective permittivity describes the coherent propagation of an electromagnetic wave in a random medium with randomly rough boundaries. We have obtained an expression, which contains the Maxwell – Garnett formula at the low-frequency limit, and the Keller formula; the latter has been proved to be in good agreement with experiments for particles whose dimensions are larger than a wavelength. (coherent light scattering)

  2. Effect of charge quantity on conduction mechanism of high- and low-resistance states during forming process in a one-transistor-one-resistor resistance random access memory

    Science.gov (United States)

    Wu, Cheng-Hsien; Chang, Ting-Chang; Tsai, Tsung-Ming; Chang, Kuan-Chang; Chu, Tian-Jian; Pan, Chih-Hung; Su, Yu-Ting; Chen, Po-Hsun; Lin, Shih-Kai; Hu, Shih-Jie; Sze, Simon M.

    2017-05-01

    The forming process is a necessary and irreversible process to activate the resistance switching behavior in a resistance random access memory (RRAM) device. However, during the forming process, an overshoot current leads to device damage and causes inferior resistance switching characteristics; consequently, the process is considered to be a key factor in device degradation. In this paper, we find that a discontinuous conduction path can be formed by a pulse forming process such that the operation current can be reduced. We further investigate how the charge quantity during the forming process affects the carrier conduction mechanism of HRS, with all experiments and results demonstrated on one-transistor-one-resistor (1T1R) devices.

  3. Total ionizing dose effect of γ-ray radiation on the switching characteristics and filament stability of HfOx resistive random access memory

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Runchen; Yu, Shimeng, E-mail: shimengy@asu.edu [School of Computing, Informatics, and Decision Systems Engineering, Arizona State University, Tempe, Arizona 85281 (United States); School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Gonzalez Velo, Yago; Chen, Wenhao; Holbert, Keith E.; Kozicki, Michael N.; Barnaby, Hugh [School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States)

    2014-05-05

    The total ionizing dose (TID) effect of gamma-ray (γ-ray) irradiation on HfOx based resistive random access memory was investigated by electrical and material characterizations. The memory states can sustain TID level ∼5.2 Mrad (HfO{sub 2}) without significant change in the functionality or the switching characteristics under pulse cycling. However, the stability of the filament is weakened after irradiation as memory states are more vulnerable to flipping under the electrical stress. X-ray photoelectron spectroscopy was performed to ascertain the physical mechanism of the stability degradation, which is attributed to the Hf-O bond breaking by the high-energy γ-ray exposure.

  4. Polarity reversion of the operation mode of HfO2-based resistive random access memory devices by inserting Hf metal layer.

    Science.gov (United States)

    Peng, Ching-Shiang; Chang, Wen-Yuan; Lin, Ming-Ho; Chen, Wei-Su; Chen, Frederick; Tsai, Ming-Jinn

    2013-03-01

    The reversion of polarity within bipolar resistive switching operation occurs in Pt/HfO2/TiN and Pt/Hf/HfO2/TiN resistive random access memory devices. This reversion of voltage polarity is the result of interface generation which induces a conduction mechanism transformation from Poole-Frenkel emission to space charge limited current mechanism. To prove the reversion of polarity, this study uses curve fitting of I-V relations to verify the conduction mechanism theoretically and physical analysis to verify the oxygen ion distribution practically. The proposed Pt/Hf/HfO2/TiN devices exhibit good resistive switching characteristics, such as good uniformity, low voltage operation, robust endurance (10(3) dc sweep), and long retention (3 x 10(4) s at 85 degrees C).

  5. Multi-step resistive switching behavior of Li-doped ZnO resistance random access memory device controlled by compliance current

    Science.gov (United States)

    Lin, Chun-Cheng; Tang, Jian-Fu; Su, Hsiu-Hsien; Hong, Cheng-Shong; Huang, Chih-Yu; Chu, Sheng-Yuan

    2016-06-01

    The multi-step resistive switching (RS) behavior of a unipolar Pt/Li0.06Zn0.94O/Pt resistive random access memory (RRAM) device is investigated. It is found that the RRAM device exhibits normal, 2-, 3-, and 4-step RESET behaviors under different compliance currents. The transport mechanism within the device is investigated by means of current-voltage curves, in-situ transmission electron microscopy, and electrochemical impedance spectroscopy. It is shown that the ion transport mechanism is dominated by Ohmic behavior under low electric fields and the Poole-Frenkel emission effect (normal RS behavior) or Li+ ion diffusion (2-, 3-, and 4-step RESET behaviors) under high electric fields.

  6. Multi-step resistive switching behavior of Li-doped ZnO resistance random access memory device controlled by compliance current

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chun-Cheng [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Department of Mathematic and Physical Sciences, R.O.C. Air Force Academy, Kaohsiung 820, Taiwan (China); Tang, Jian-Fu; Su, Hsiu-Hsien [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Hong, Cheng-Shong; Huang, Chih-Yu [Department of Electronic Engineering, National Kaohsiung Normal University, Kaohsiung 802, Taiwan (China); Chu, Sheng-Yuan, E-mail: chusy@mail.ncku.edu.tw [Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China)

    2016-06-28

    The multi-step resistive switching (RS) behavior of a unipolar Pt/Li{sub 0.06}Zn{sub 0.94}O/Pt resistive random access memory (RRAM) device is investigated. It is found that the RRAM device exhibits normal, 2-, 3-, and 4-step RESET behaviors under different compliance currents. The transport mechanism within the device is investigated by means of current-voltage curves, in-situ transmission electron microscopy, and electrochemical impedance spectroscopy. It is shown that the ion transport mechanism is dominated by Ohmic behavior under low electric fields and the Poole-Frenkel emission effect (normal RS behavior) or Li{sup +} ion diffusion (2-, 3-, and 4-step RESET behaviors) under high electric fields.

  7. Self-compliance Pt/HfO2/Ti/Si one-diode-one-resistor resistive random access memory device and its low temperature characteristics

    Science.gov (United States)

    Lu, Chao; Yu, Jue; Chi, Xiao-Wei; Lin, Guang-Yang; Lan, Xiao-Ling; Huang, Wei; Wang, Jian-Yuan; Xu, Jian-Fang; Wang, Chen; Li, Cheng; Chen, Song-Yan; Liu, Chunli; Lai, Hong-Kai

    2016-04-01

    A bipolar one-diode-one-resistor (1D1R) device with a Pt/HfO2/Ti/n-Si(001) structure was demonstrated. The 1D1R resistive random access memory (RRAM) device consists of a Ti/n-Si(001) diode and a Pt/HfO2/Ti resistive switching cell. By using the Ti layer as the shared electrode for both the diode and the resistive switching cell, the 1D1R device exhibits the property of stable self-compliance and the characteristic of robust resistive switching with high uniformity. The high/low resistance ratio reaches 103. The electrical RESET/SET curve does not deteriorate after 68 loops. Low-temperature studies show that the 1D1R RRAM device has a critical working temperature of 250 K, and at temperatures below 250 K, the device fails to switch its resistances.

  8. Low leakage Ru-strontium titanate-Ru metal-insulator-metal capacitors for sub-20 nm technology node in dynamic random access memory

    Energy Technology Data Exchange (ETDEWEB)

    Popovici, M., E-mail: Mihaela.Ioana.Popovici@imec.be; Swerts, J.; Redolfi, A.; Kaczer, B.; Aoulaiche, M.; Radu, I.; Clima, S.; Everaert, J.-L.; Van Elshocht, S.; Jurczak, M. [Imec, Leuven 3001 (Belgium)

    2014-02-24

    Improved metal-insulator-metal capacitor (MIMCAP) stacks with strontium titanate (STO) as dielectric sandwiched between Ru as top and bottom electrode are shown. The Ru/STO/Ru stack demonstrates clearly its potential to reach sub-20 nm technology nodes for dynamic random access memory. Downscaling of the equivalent oxide thickness, leakage current density (J{sub g}) of the MIMCAPs, and physical thickness of the STO have been realized by control of the Sr/Ti ratio and grain size using a heterogeneous TiO{sub 2}/STO based nanolaminate stack deposition and a two-step crystallization anneal. Replacement of TiN with Ru as both top and bottom electrodes reduces the amount of electrically active defects and is essential to achieve a low leakage current in the MIM capacitor.

  9. Total ionizing dose effect of γ-ray radiation on the switching characteristics and filament stability of HfOx resistive random access memory

    Science.gov (United States)

    Fang, Runchen; Gonzalez Velo, Yago; Chen, Wenhao; Holbert, Keith E.; Kozicki, Michael N.; Barnaby, Hugh; Yu, Shimeng

    2014-05-01

    The total ionizing dose (TID) effect of gamma-ray (γ-ray) irradiation on HfOx based resistive random access memory was investigated by electrical and material characterizations. The memory states can sustain TID level ˜5.2 Mrad (HfO2) without significant change in the functionality or the switching characteristics under pulse cycling. However, the stability of the filament is weakened after irradiation as memory states are more vulnerable to flipping under the electrical stress. X-ray photoelectron spectroscopy was performed to ascertain the physical mechanism of the stability degradation, which is attributed to the Hf-O bond breaking by the high-energy γ-ray exposure.

  10. On Using the Volatile Mem-Capacitive Effect of TiO2 Resistive Random Access Memory to Mimic the Synaptic Forgetting Process

    Science.gov (United States)

    Sarkar, Biplab; Mills, Steven; Lee, Bongmook; Pitts, W. Shepherd; Misra, Veena; Franzon, Paul D.

    2018-02-01

    In this work, we report on mimicking the synaptic forgetting process using the volatile mem-capacitive effect of a resistive random access memory (RRAM). TiO2 dielectric, which is known to show volatile memory operations due to migration of inherent oxygen vacancies, was used to achieve the volatile mem-capacitive effect. By placing the volatile RRAM candidate along with SiO2 at the gate of a MOS capacitor, a volatile capacitance change resembling the forgetting nature of a human brain is demonstrated. Furthermore, the memory operation in the MOS capacitor does not require a current flow through the gate dielectric indicating the feasibility of obtaining low power memory operations. Thus, the mem-capacitive effect of volatile RRAM candidates can be attractive to the future neuromorphic systems for implementing the forgetting process of a human brain.

  11. Flexible resistive random access memory devices by using NiO x /GaN microdisk arrays fabricated on graphene films

    Science.gov (United States)

    Lee, Keundong; Park, Jong-woo; Tchoe, Youngbin; Yoon, Jiyoung; Chung, Kunook; Yoon, Hosang; Lee, Sangik; Yoon, Chansoo; Park, Bae Ho; Yi, Gyu-Chul

    2017-05-01

    We report flexible resistive random access memory (ReRAM) arrays fabricated by using NiO x /GaN microdisk arrays on graphene films. The ReRAM device was created from discrete GaN microdisk arrays grown on graphene films produced by chemical vapor deposition, followed by deposition of NiO x thin layers and Au metal contacts. The microdisk ReRAM arrays were transferred to flexible plastic substrates by a simple lift-off technique. The electrical and memory characteristics of the ReRAM devices were investigated under bending conditions. Resistive switching characteristics, including cumulative probability, endurance, and retention, were measured. After 1000 bending repetitions, no significant change in the device characteristics was observed. The flexible ReRAM devices, constructed by using only inorganic materials, operated reliably at temperatures as high as 180 °C.

  12. Nanoscale CuO solid-electrolyte-based conductive-bridging, random-access memory cell with a TiN liner

    Science.gov (United States)

    Lee, Jong-Sun; Kim, Dong-Won; Kim, Hea-Jee; Jin, Soo-Min; Song, Myung-Jin; Kwon, Ki-Hyun; Park, Jea-Gun; Jalalah, Mohammed; Al-Hajry, Ali

    2018-01-01

    The Conductive-bridge random-access memory (CBRAM) cell is a promising candidate for a terabit-level non-volatile memory due to its remarkable advantages. We present for the first time TiN as a diffusion barrier in CBRAM cells for enhancing their reliability. CuO solid-electrolyte-based CBRAM cells implemented with a 0.1-nm TiN liner demonstrated better non-volatile memory characteristics such as 106 AC write/erase endurance cycles with 100-μs AC pulse width and a long retention time of 7.4-years at 85 °C. In addition, the analysis of Ag diffusion in the CBRAM cell suggests that the morphology of the Ag filaments in the electrolyte can be effectively controlled by tuning the thickness of the TiN liner. These promising results pave the way for faster commercialization of terabit-level non-volatile memories.

  13. Nonvolatile Static Random Access Memory Using Resistive Switching Devices: Variable-Transconductance Metal-Oxide-Semiconductor Field-Effect-Transistor Approach

    Science.gov (United States)

    Yamamoto, Shuu'ichirou; Shuto, Yusuke; Sugahara, Satoshi

    2010-04-01

    In this paper, we present a variable-transconductance (gm) metal-oxide-semiconductor field-effect-transistor (VGm-MOSFET) architecture using a nonpolar resistive switching device (RSD) for nonvolatile bistable circuit applications. The architecture can be achieved by connecting an RSD to the source terminal of an ordinary MOSFET. The current drive capability of the VGm-MOSFET can be modified by resistance states of the connected RSD, which is a very useful function for nonvolatile bistable circuits, such as nonvolatile static random access memory (NV-SRAM) and nonvolatile flip-flop (NV-FF). NV-SRAM can be easily configured by connecting two additional VGm-MOSFETs to the storage nodes of a standard SRAM cell. Using our developed SPICE macromodel for nonpolar RSDs, successful circuit operations of the proposed NV-SRAM cell were confirmed.

  14. Quantifying data retention of perpendicular spin-transfer-torque magnetic random access memory chips using an effective thermal stability factor method

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Luc, E-mail: luc.thomas@headway.com; Jan, Guenole; Le, Son; Wang, Po-Kang [TDK-Headway Technologies, Inc., 463 S. Milpitas Boulevard, Milpitas, California 95035 (United States)

    2015-04-20

    The thermal stability of perpendicular Spin-Transfer-Torque Magnetic Random Access Memory (STT-MRAM) devices is investigated at chip level. Experimental data are analyzed in the framework of the Néel-Brown model including distributions of the thermal stability factor Δ. We show that in the low error rate regime important for applications, the effect of distributions of Δ can be described by a single quantity, the effective thermal stability factor Δ{sub eff}, which encompasses both the median and the standard deviation of the distributions. Data retention of memory chips can be assessed accurately by measuring Δ{sub eff} as a function of device diameter and temperature. We apply this method to show that 54 nm devices based on our perpendicular STT-MRAM design meet our 10 year data retention target up to 120 °C.

  15. An orthogonal wavelet division multiple-access processor architecture for LTE-advanced wireless/radio-over-fiber systems over heterogeneous networks

    Science.gov (United States)

    Mahapatra, Chinmaya; Leung, Victor CM; Stouraitis, Thanos

    2014-12-01

    The increase in internet traffic, number of users, and availability of mobile devices poses a challenge to wireless technologies. In long-term evolution (LTE) advanced system, heterogeneous networks (HetNet) using centralized coordinated multipoint (CoMP) transmitting radio over optical fibers (LTE A-ROF) have provided a feasible way of satisfying user demands. In this paper, an orthogonal wavelet division multiple-access (OWDMA) processor architecture is proposed, which is shown to be better suited to LTE advanced systems as compared to orthogonal frequency division multiple access (OFDMA) as in LTE systems 3GPP rel.8 (3GPP, http://www.3gpp.org/DynaReport/36300.htm). ROF systems are a viable alternative to satisfy large data demands; hence, the performance in ROF systems is also evaluated. To validate the architecture, the circuit is designed and synthesized on a Xilinx vertex-6 field-programmable gate array (FPGA). The synthesis results show that the circuit performs with a clock period as short as 7.036 ns (i.e., a maximum clock frequency of 142.13 MHz) for transform size of 512. A pipelined version of the architecture reduces the power consumption by approximately 89%. We compare our architecture with similar available architectures for resource utilization and timing and provide performance comparison with OFDMA systems for various quality metrics of communication systems. The OWDMA architecture is found to perform better than OFDMA for bit error rate (BER) performance versus signal-to-noise ratio (SNR) in wireless channel as well as ROF media. It also gives higher throughput and mitigates the bad effect of peak-to-average-power ratio (PAPR).

  16. Effect of Access to an Electronic Medical Resource on Performance Characteristics of a Certification Examination: A Randomized Controlled Trial.

    Science.gov (United States)

    Lipner, Rebecca S; Brossman, Bradley G; Samonte, Kelli M; Durning, Steven J

    2017-09-05

    Electronic resources are increasingly used in medical practice. Their use during high-stakes certification examinations has been advocated by many experts, but whether doing so would affect the capacity to differentiate between high and low abilities is unknown. To determine the effect of electronic resources on examination performance characteristics. Randomized controlled trial. Medical certification program. 825 physicians initially certified by the American Board of Internal Medicine (ABIM) who passed the Internal Medicine Certification examination or sat for the Internal Medicine Maintenance of Certification (IM-MOC) examination in 2012 to 2015. Participants were randomly assigned to 1 of 4 conditions: closed book using typical or additional time, or open book (that is, UpToDate [Wolters Kluwer]) using typical or additional time. All participants took the same modified version of the IM-MOC examination. Primary outcomes included item difficulty (how easy or difficult the question was), item discrimination (how well the question differentiated between high and low abilities), and average question response time. Secondary outcomes included examination dimensionality (that is, the number of factors measured) and test-taking strategy. Item response theory was used to calculate question characteristics. Analysis of variance compared differences among conditions. Closed-book conditions took significantly less time than open-book conditions (mean, 79.2 seconds [95% CI, 78.5 to 79.9 seconds] vs. 110.3 seconds [CI, 109.2 to 111.4 seconds] per question). Mean discrimination was statistically significantly higher for open-book conditions (0.34 [CI, 0.32 to 0.35] vs. 0.39 [CI, 0.37 to 0.41] per question). A strong single dimension showed that the examination measured the same factor with or without the resource. Only 1 electronic resource was evaluated. Inclusion of an electronic resource with time constraints did not adversely affect test performance and did not change

  17. The Sound Access Parent Outcomes Instrument (SAPOI): Construction of a new instrument for children with severe multiple disabilities who use cochlear implants or hearing aids.

    Science.gov (United States)

    Hayward, Denyse V; Ritter, Kathryn; Mousavi, Amin; Vatanapour, Shabnam

    2016-01-01

    To report on the Phase 2 development of the Sound Access Parent Outcomes Instrument (SAPOI), a new instrument focused on formalizing outcomes that parents of children with severe multiple disabilities (SMD) who use amplification prioritize as important. Phase 2 of this project involved item selection and refinement of the SAPOI based on (a) Phase 1 study participant input, (b) clinical specialist feedback, and (c) test-retest instrument reliability. Phase 1 participant responses were utilized to construct a draft version of the SAPOI. Next, clinical specialists examined the instrument for content validity and utility and instrument reliability was examined through a test-retest process with parents of children with SMD. The draft SAPOI was constructed based on Phase 1 participant input. Clinical specialists supported content validity and utility of the instrument and the inclusion of 19 additional items across four categories, namely Child Affect, Child Interaction, Parent Well-being, and Child's Device Use. The SAPOI was completed twice at one-month intervals by parents of children with SMD to examine instrument reliability across the four categories (Child Affect, Child Interaction, Parent Well-being, and Child's Device Use). Instrument reliability was strong-to-excellent across all four sections. The SAPOI shows promise as a much-needed addition to the assessment battery currently used for children with SMD who use cochlear implants and hearing aids. It provides valuable information regarding outcomes resulting from access to sound in this population that currently used assessments do not identify.

  18. Auction pricing of network access for North American railways

    DEFF Research Database (Denmark)

    Harrod, Steven

    2013-01-01

    The question of pricing train paths for "open access" railway networks in North America is discussed. An auction process is suggested as necessary to maintain transparency in the contracting process. Multiple random samples of auction pricing for a single track railway line demonstrate that the i......The question of pricing train paths for "open access" railway networks in North America is discussed. An auction process is suggested as necessary to maintain transparency in the contracting process. Multiple random samples of auction pricing for a single track railway line demonstrate...

  19. Glatiramer Acetate in Treatment of Multiple Sclerosis: A Toolbox of Random Co-Polymers for Targeting Inflammatory Mechanisms of both the Innate and Adaptive Immune System?

    Directory of Open Access Journals (Sweden)

    Thomas Vorup-Jensen

    2012-11-01

    Full Text Available Multiple sclerosis is a disease of the central nervous system, resulting in the demyelination of neurons, causing mild to severe symptoms. Several anti-inflammatory treatments now play a significant role in ameliorating the disease. Glatiramer acetate (GA is a formulation of random polypeptide copolymers for the treatment of relapsing-remitting MS by limiting the frequency of attacks. While evidence suggests the influence of GA on inflammatory responses, the targeted molecular mechanisms remain poorly understood. Here, we review the multiple pharmacological modes-of-actions of glatiramer acetate in treatment of multiple sclerosis. We discuss in particular a newly discovered interaction between the leukocyte-expressed integrin αMβ2 (also called Mac-1, complement receptor 3, or CD11b/CD18 and perspectives on the GA co-polymers as an influence on the function of the innate immune system.

  20. Improving the alcohol retail environment to reduce youth access: a randomized community trial of a best practices toolkit intervention.

    Science.gov (United States)

    Wolff, Lisa S; El Ayadi, Alison M; Lyons, Nancy J; Herr-Zaya, Kathleen; Noll, Debra; Perfas, Fernando; Rots, Gisela

    2011-06-01

    Underage alcohol use remains a significant public health problem throughout the United States and has important consequences for the health of individuals and communities. The objective of this study was to assess the impact of distributing an alcohol retailer toolkit via direct mail on increasing positive alcohol retailer attitudes towards checking IDs, encouraging retail managers to formalize ID checking procedures with their employees, and promoting consumers to be prepared to show ID when purchasing alcohol. This community randomized study included five matched Massachusetts community pairs. Our analysis sample consisted of 209 retailers (77 intervention; 132 control). In models adjusted for baseline response and matching community and establishment characteristics, intervention communities reported posting, on average, one additional sign or wall decal in their establishments (β = 0.937, P = 0.0069), and a twofold higher odds of handing out written materials on ID checking to staff (OR: 2.074, 95%CI: 1.003-4.288) compared to control establishments. However, the intervention was not found to have an effect on changing establishment policies, retailer attitudes, or other establishment practices. Intervention retailers perceived all components of the toolkit to be very useful for their establishments, and nearly all reported having shared materials with their employees and customers. These results suggest that some significant changes in alcohol retailer establishment practices can be achieved among motivated owners or managers through the distribution of a toolkit targeting best retailer practices. We do, however, recommend that future program planners consider alternative dissemination and marketing strategies beyond direct mail to encourage greater utilization.

  1. Randomized controlled clinical trial to access efficacy and safety of miltefosine in the treatment of cutaneous leishmaniasis Caused by Leishmania (Viannia) guyanensis in Manaus, Brazil.

    Science.gov (United States)

    Chrusciak-Talhari, Anette; Dietze, Reynaldo; Chrusciak Talhari, Carolina; da Silva, Roberto Moreira; Gadelha Yamashita, Ellen Priscila; de Oliveira Penna, Gerson; Lima Machado, Paulo Roberto; Talhari, Sinésio

    2011-02-01

    Miltefosine has been used in the treatment of several new world cutaneous leishmaniasis (CL) species with variable efficacy. Our study is the first evidence on its clinical efficacy in Leishmania (Viannia) guyanensis. In this phase II/III randomized clinical trial, 90 CL patients were randomly allocated (2:1) to oral miltefosine (2.5 mg/kg/day/28 days) (N = 60) or parenteral antimony (15-20 mg/Sb/kg/day/20 days) (N = 30) according to age groups: 2-12 y/o and 13-65 y/o. Patients were human immunodeficiency virus (HIV) noninfected parasitological proven CL without previous treatment. Definitive cure was accessed at 6 months follow-up visit. No severe adverse events occurred. Vomiting was the most frequent adverse event (48.3%) followed by nausea (8.6%) and diarrhea (6.7%). Cure rates were 71.4% (95% confidence interval [CI] = 57.8-82.7) and 53.6% (95% CI = 33.9-72.5) (P = 0.05) for miltefosine and antimonial, respectively. There were no differences in cure rates between age groups within the same treatment arms. Miltefosine was safe and relatively well tolerated and cure rate was higher than antimony.

  2. Increasing Access to Mental Health Care With Breathe, an Internet-Based Program for Anxious Adolescents: Study Protocol for a Pilot Randomized Controlled Trial.

    Science.gov (United States)

    Newton, Amanda S; Wozney, Lori; Bagnell, Alexa; Fitzpatrick, Eleanor; Curtis, Sarah; Jabbour, Mona; Johnson, David; Rosychuk, Rhonda J; Young, Michael; Ohinmaa, Arto; Joyce, Anthony; McGrath, Patrick

    2016-01-29

    There is a demand to make first-line treatments, including cognitive behavioural therapy (CBT) for adolescent anxiety disorders, more widely available. Internet-based CBT is proposed to circumvent access and availability barriers and reduce health care system costs. Recent reviews suggest more evidence is needed to establish the treatment effects of Internet-based CBT in children and adolescents and to determine related economic impacts. This pilot trial aims to collect the necessary data to inform the planning of a full-scale RCT to test the effectiveness of the Internet-based CBT program Breathe (Being Real, Easing Anxiety: Tools Helping Electronically). We are conducting a 27-month, 2-arm parallel-group, pilot randomized controlled trial (RCT). Outcomes will inform the planning of a full-scale RCT aimed to test the effectiveness of Internet-based CBT with a population of adolescents with moderate to mild anxiety problems. In the pilot RCT we will: (1) define a minimal clinically important difference (MCID) for the primary outcome measure (total anxiety score using the Multidimensional Anxiety Scale for Children); (2) determine a sample size for the full-scale RCT; (3) estimate recruitment and retention rates; (4) measure intervention acceptability to inform critical intervention changes; (5) determine the use of co-interventions; and (6) conduct a cost-consequence analysis to inform a cost-effectiveness analysis in the full-scale RCT. Adolescents aged 13-17 years seeking care for an anxiety complaint from a participating emergency department, mobile or school-based crisis team, or primary care clinic are being screened for interest and eligibility. Enrolled adolescents are being randomly allocated to either 8 weeks of Internet-based CBT with limited telephone and e-mail support, or a control group with access to a static webpage listing anxiety resources. Adolescents are randomly assigned using a computer generated allocation sequence. Data are being collected

  3. A spin transfer torque magnetoresistance random access memory-based high-density and ultralow-power associative memory for fully data-adaptive nearest neighbor search with current-mode similarity evaluation and time-domain minimum searching

    Science.gov (United States)

    Ma, Yitao; Miura, Sadahiko; Honjo, Hiroaki; Ikeda, Shoji; Hanyu, Takahiro; Ohno, Hideo; Endoh, Tetsuo

    2017-04-01

    A high-density nonvolatile associative memory (NV-AM) based on spin transfer torque magnetoresistive random access memory (STT-MRAM), which achieves highly concurrent and ultralow-power nearest neighbor search with full adaptivity of the template data format, has been proposed and fabricated using the 90 nm CMOS/70 nm perpendicular-magnetic-tunnel-junction hybrid process. A truly compact current-mode circuitry is developed to realize flexibly controllable and high-parallel similarity evaluation, which makes the NV-AM adaptable to any dimensionality and component-bit of template data. A compact dual-stage time-domain minimum searching circuit is also developed, which can freely extend the system for more template data by connecting multiple NM-AM cores without additional circuits for integrated processing. Both the embedded STT-MRAM module and the computing circuit modules in this NV-AM chip are synchronously power-gated to completely eliminate standby power and maximally reduce operation power by only activating the currently accessed circuit blocks. The operations of a prototype chip at 40 MHz are demonstrated by measurement. The average operation power is only 130 µW, and the circuit density is less than 11 µm2/bit. Compared with the latest conventional works in both volatile and nonvolatile approaches, more than 31.3% circuit area reductions and 99.2% power improvements are achieved, respectively. Further power performance analyses are discussed, which verify the special superiority of the proposed NV-AM in low-power and large-memory-based VLSIs.

  4. The vitamin D to ameliorate multiple sclerosis (VIDAMS) trial: study design for a multicenter, randomized, double-blind controlled trial of vitamin D in multiple sclerosis.

    Science.gov (United States)

    Bhargava, Pavan; Cassard, Sandra; Steele, Sonya U; Azevedo, Christina; Pelletier, Daniel; Sugar, Elizabeth A; Waubant, Emmanuelle; Mowry, Ellen M

    2014-11-01

    Lower levels of vitamin D are associated with increased MS risk and with greater clinical and brain MRI activity in established relapsing MS. The VIDAMS trial (NCT01490502) is evaluating whether high-dose vitamin D supplementation reduces the risk of MS activity. Eligibility criteria include diagnosis of RRMS, age 18 to 50 years, and Expanded Disability Status Scale ≤4.0. Disease duration and activity requirements depend on whether 2005 or 2010 criteria are used for diagnosis. Enrollment is restricted based on prior MS therapy exposure and recent vitamin D use. After completing a one-month run-in of glatiramer acetate, 172 patients will be randomized 1:1 to oral vitamin D(3) 5000 IU versus 600 IU daily. Clinical visits occur every 12 weeks for 96 weeks. Sixteen sites throughout the United States are participating in the trial. Complete enrollment is expected by late 2014, with follow-up through 2016. No interim analyses are planned. The primary outcome for the trial is the proportion of patients experiencing a relapse in each group. Other clinical, patient-reported, and MRI outcomes will be evaluated. The VIDAMS trial will provide critical information about the safety and efficacy of vitamin D therapy in RRMS, with implications for MS patients worldwide. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Randomizing Multiple Contingency Components to Decrease Disruptive Behaviors and Increase Student Engagement in an Urban Second-Grade Classroom

    Science.gov (United States)

    McKissick, Chele; Hawkins, Renee O.; Lentz, Francis E.; Hailley, Jennifer; McGuire, Shannon

    2010-01-01

    Disruptive behaviors displayed in the classroom interfere with learning by taking time away from academic instruction. This study investigated the effects of randomizing components within an interdependent group contingency for group disruptive behavior and engagement levels of 26 students in a second-grade classroom in an urban Midwestern school.…

  6. Efficient rare-event simulation for multiple jump events in regularly varying random walks and compound Poisson processes

    NARCIS (Netherlands)

    B. Chen (Bohan); J. Blanchet; C.H. Rhee (Chang-Han); A.P. Zwart (Bert)

    2017-01-01

    textabstractWe propose a class of strongly efficient rare event simulation estimators for random walks and compound Poisson processes with a regularly varying increment/jump-size distribution in a general large deviations regime. Our estimator is based on an importance sampling strategy that hinges

  7. Fundamental Issues of Multiple Accessing

    Science.gov (United States)

    1983-11-01

    version of the tree algorithm.-- --- - .L F - . a - - .- GET NEWa~ EPCH Epoc str fro en of l ast epc wit legt 1~a.~ - *~- . 08X -. -- ~- 13 states (circle...right hand side of the above inequality gives s < k C Mt /MC" The maximum occurs for the smallest k satisfying k M-k C > (k + l) P.4k.,) C For large M...BZ li< Mt I We assume that the receiver m, 1<m M, is assigned to obtain an estimate for the message of user m. In the process, the receiver m may have

  8. Cognitive behavioral therapy positively affects fatigue in patients with multiple sclerosis: Results of a randomized controlled trial

    NARCIS (Netherlands)

    van den Akker, Lizanne E.; Beckerman, Heleen; Collette, Emma H.; Twisk, Jos W. R.; Bleijenberg, Gijs; Dekker, Joost; Knoop, Hans; de Groot, Vincent

    2017-01-01

    Background: Fatigue is a common symptom in multiple sclerosis (MS) and often restricts societal participation. Cognitive behavioral therapy (CBT) may alleviate MS-related fatigue, but evidence in literature is inconclusive. Objective: To evaluate the effectiveness of CBT to improve MS-related

  9. Up-front fludarabine impairs stem cell harvest in multiple myeloma: report from an interim analysis of the NMSG 13/03 randomized placebo controlled phase II trial

    DEFF Research Database (Denmark)

    Johnsen, Hans Erik; Knudsen, Lene Meldgaard; Mylin, Anne Kærsgaard

    2009-01-01

    toxicity and safety analysis, the trial was stopped following inclusion of 34 of a planned 80 patients due to a reduced number of patients (4/17) actually harvested in the experimental arm compared to the control arm (11/17; p lower than 0.05). In conclusion, the scheduled fludarabine dosage in 2 cycles......The impact of chemotherapy resistant B cells in multiple myeloma (MM) needs to be evaluated by in vivo targeted therapy. Here we report the conclusions from a phase II randomized, placebo controlled trial adding fludarabine to the induction with cyclophosphamide-dexamethasone. Based on an interim...

  10. Up-front fludarabine impairs stem cell harvest in multiple myeloma: report of the NMSG 13/03 randomized placebo controlled phase II trial

    DEFF Research Database (Denmark)

    Johnsen, Hans E.; Meldgaard Knudsen, Lene; Mylin, Anne K.

    2009-01-01

    toxicity and safety analysis, the trial was stopped following inclusion of 34 of a planned 80 patients due to a reduced number of patients (4/17) actually harvested in the experimental arm compared to the control arm (11/17; p...The impact of chemotherapy resistant B cells in multiple myeloma (MM) needs to be evaluated by in vivo targeted therapy. Here we report the conlusions from a phase II randomized, placebo controlled trial adding fludarabine to the induction with cyclophosphamide-dexamethasone. Based on an interim...

  11. Comparing cluster-level dynamic treatment regimens using sequential, multiple assignment, randomized trials: Regression estimation and sample size considerations

    OpenAIRE

    NeCamp, Timothy; Kilbourne, Amy; Almirall, Daniel

    2016-01-01

    Cluster-level dynamic treatment regimens can be used to guide sequential, intervention or treatment decision-making at the cluster level in order to improve outcomes at the individual or patient-level. In a cluster-level DTR, the intervention or treatment is potentially adapted and re-adapted over time based on changes in the cluster that could be impacted by prior intervention, including based on aggregate measures of the individuals or patients that comprise it. Cluster-randomized sequentia...

  12. Three nested randomized controlled trials of peer-only or multiple stakeholder group feedback within Delphi surveys during core outcome and information set development.

    Science.gov (United States)

    Brookes, Sara T; Macefield, Rhiannon C; Williamson, Paula R; McNair, Angus G; Potter, Shelley; Blencowe, Natalie S; Strong, Sean; Blazeby, Jane M

    2016-08-17

    Methods for developing a core outcome or information set require involvement of key stakeholders to prioritise many items and achieve agreement as to the core set. The Delphi technique requires participants to rate the importance of items in sequential questionnaires (or rounds) with feedback provided in each subsequent round such that participants are able to consider the views of others. This study examines the impact of receiving feedback from different stakeholder groups, on the subsequent rating of items and the level of agreement between stakeholders. Randomized controlled trials were nested within the development of three core sets each including a Delphi process with two rounds of questionnaires, completed by patients and health professionals. Participants rated items from 1 (not essential) to 9 (absolutely essential). For round 2, participants were randomized to receive feedback from their peer stakeholder group only (peer) or both stakeholder groups separately (multiple). Decisions as to which items to retain following each round were determined by pre-specified criteria. Whilst type of feedback did not impact on the percentage of items for which a participant subsequently changed their rating, or the magnitude of change, it did impact on items retained at the end of round 2. Each core set contained discordant items retained by one feedback group but not the other (3-22 % discordant items). Consensus between patients and professionals in items to retain was greater amongst those receiving multiple group feedback in each core set (65-82 % agreement for peer-only feedback versus 74-94 % for multiple feedback). In addition, differences in round 2 scores were smaller between stakeholder groups receiving multiple feedback than between those receiving peer group feedback only. Variability in item scores across stakeholders was reduced following any feedback but this reduction was consistently greater amongst the multiple feedback group. In the development of

  13. Effect of whole-body exposure to the 848.5 MHz code division multiple access (CDMA) electromagnetic field on adult neurogenesis in the young, healthy rat brain.

    Science.gov (United States)

    Kim, Hye Sun; Kim, Yeon Ju; Lee, Yu Hee; Lee, Yun-Sil; Choi, Hyung Do; Pack, Jeong-Ki; Kim, Nam; Ahn, Young Hwan

    2015-04-01

    Whether exposure to the 848.5 MHz code division multiple access (CDMA) signal affects adult neurogenesis is unclear. An animal experiment was performed with a reverberation chamber designed as a whole-body CDMA exposure system. Male Sprague-Dawley rats were assigned to three groups (n = 6 per group): Cage-control, sham-exposed, and CDMA-exposed groups. Rats in the CDMA-exposed group were exposed to the CDMA signal at a 2 W/kg whole-body specific absorption rate (SAR) for 1 or 8 h daily, 5 days per week, for 2 weeks. Rats received a single intraperitoneal injection of Bromodeoxyuridine (BrdU) to label proliferative cells daily for the last five consecutive days of CDMA signal exposure. An unbiased stereological method was used to estimate the number of BrdU(+) cells in the subventricular zone (SVZ) and dentate gyrus (DG). We found no significant changes in the number of BrdU(+) cells in the SVZ or DG in the CDMA-exposed rats, compared with rats in the cage-control and sham-exposed groups (p > 0.05). Our results suggest that exposure to the CDMA signal does not affect neurogenesis in the adult rat brain, at least under our experimental conditions.

  14. Multiple-modality exercise and mind-motor training to improve cardiovascular health and fitness in older adults at risk for cognitive impairment: A randomized controlled trial.

    Science.gov (United States)

    Boa Sorte Silva, Narlon C; Gregory, Michael A; Gill, Dawn P; Petrella, Robert J

    The effects of multiple-modality exercise on arterial stiffening and cardiovascular fitness has not been fully explored. To explore the influence of a 24-week multiple-modality exercise program associated with a mind-motor training in cardiovascular health and fitness in community-dwelling older adults, compared to multiple-modality exercise (M2) alone. Participants (n=127, aged 67.5 [7.3] years, 71% females) were randomized to either M4 or M2 groups. Both groups received multiple-modality exercise intervention (60min/day, 3days/week for 24-weeks); however, the M4 group underwent additional 15min of mind-motor training, whereas the M2 group received 15min of balance training. Participants were assessed at 24-weeks and after a 28-week non-contact follow-up (52-weeks). at 52-weeks, the M4 group demonstrated a greater VO2max (ml/kg/min) compared to the M2 group (mean difference: 2.39, 95% CI: 0. 61 to 4.16, p=0.009). Within-group analysis indicated that the M4 group demonstrated a positive change in VO2max at 24-weeks (mean change: 1.93, 95% CI: 0.82 to 3.05, p=0.001) and 52-weeks (4.02, 95% CI: 2.71 to 5.32, p=0.001). Similarly, the M2 group increased VO2max at 24-weeks (2.28, 95% CI: 1.23 to 3.32, pMind-motor training associated with multiple-modality exercise can positively impact cardiovascular fitness to the same extent as multiple-modality exercise alone. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. Effect of multiple physiotherapy sessions on functional outcomes in the initial postoperative period after primary total hip replacement: a randomized controlled trial.

    Science.gov (United States)

    Stockton, Kellie A; Mengersen, Kerrie A

    2009-10-01

    Stockton KA, Mengersen KA. Effect of multiple physiotherapy sessions on functional outcomes in the initial postoperative period after primary total hip replacement: a randomized controlled trial. To determine whether increasing physiotherapy input from once to twice per day will result in earlier achievement of functional milestones (ie, independence in mobility and transfers) and decreased length of stay (LOS) in patients undergoing a primary total hip replacement. Randomized controlled trial. Metropolitan private hospital. Patients (N=57) with primary total hip replacement were randomly assigned to the twice daily (treatment, n=30) and once daily (control, n=27) groups. Patients who chose to attend hydrotherapy were excluded from the randomization process; however, they gave consent for outcome measures to be collected for comparison with the randomized groups. The control group received usual care, and the treatment group received twice-daily physiotherapy from day 1 after surgery to discharge. The Iowa Level of Assistance at postoperative days 3 and 6 and LOS. This study demonstrates that patients who received twice-daily land-based physiotherapy after primary total hip replacement attained earlier achievement of functional milestones than patients that received once-daily physiotherapy. A statistically significant (P=.041) but not clinically significant difference was evident in the Iowa Level of Assistance score at day 3. There was no difference between the groups in Iowa Level of Assistance measures on day 6 or on LOS. Patients who received twice-daily physiotherapy showed a trend toward earlier achievement of functional milestones; however, this finding did not translate to decreased LOS.

  16. a-SiNx:H-based ultra-low power resistive random access memory with tunable Si dangling bond conduction paths

    Science.gov (United States)

    Jiang, Xiaofan; Ma, Zhongyuan; Xu, Jun; Chen, Kunji; Xu, Ling; Li, Wei; Huang, Xinfan; Feng, Duan

    2015-10-01

    The realization of ultra-low power Si-based resistive switching memory technology will be a milestone in the development of next generation non-volatile memory. Here we show that a high performance and ultra-low power resistive random access memory (RRAM) based on an Al/a-SiNx:H/p+-Si structure can be achieved by tuning the Si dangling bond conduction paths. We reveal the intrinsic relationship between the Si dangling bonds and the N/Si ratio x for the a-SiNx:H films, which ensures that the programming current can be reduced to less than 1 μA by increasing the value of x. Theoretically calculated current-voltage (I-V ) curves combined with the temperature dependence of the I-V characteristics confirm that, for the low-resistance state (LRS), the Si dangling bond conduction paths obey the trap-assisted tunneling model. In the high-resistance state (HRS), conduction is dominated by either hopping or Poole-Frenkel (P-F) processes. Our introduction of hydrogen in the a-SiNx:H layer provides a new way to control the Si dangling bond conduction paths, and thus opens up a research field for ultra-low power Si-based RRAM.

  17. Modulation of surface trap induced resistive switching by electrode annealing in individual PbS micro/nanowire-based devices for resistance random access memory.

    Science.gov (United States)

    Zheng, Jianping; Cheng, Baochang; Wu, Fuzhang; Su, Xiaohui; Xiao, Yanhe; Guo, Rui; Lei, Shuijin

    2014-12-10

    Bipolar resistive switching (RS) devices are commonly believed as a promising candidate for next generation nonvolatile resistance random access memory (RRAM). Here, two-terminal devices based on individual PbS micro/nanowires with Ag electrodes are constructed, whose electrical transport depends strongly on the abundant surface and bulk trap states in micro/nanostructures. The surface trap states can be filled/emptied effectively at negative/positive bias voltage, respectively, and the corresponding rise/fall of the Fermi level induces a variation in a degenerate/nondegenerate state, resulting in low/high resistance. Moreover, the filling/emptying of trap states can be utilized as RRAM. After annealing, the surface trap state can almost be eliminated completely; while most of the bulk trap states can still remain. In the devices unannealed and annealed at both ends, therefore, the symmetrical back-to-back Fowler-Nordheim tunneling with large ON/OFF resistance ratio and Poole-Frenkel emission with poor hysteresis can be observed under cyclic sweep voltage, respectively. However, a typical bipolar RS behavior can be observed effectively in the devices annealed at one end. The acquirement of bipolar RS and nonvolatile RRAM by the modulation of electrode annealing demonstrates the abundant trap states in micro/nanomaterials will be advantageous to the development of new type electronic components.

  18. Excellent scalability including self-heating phenomena of vertical-channel field-effect-diode type capacitor-less one transistor dynamic random access memory cell

    Science.gov (United States)

    Imamoto, Takuya; Endoh, Tetsuo

    2014-01-01

    The scalability study and the impact of the self-heating effect (SHE) on memory operation of the bulk vertical-channel field effect diode (FED) type capacitorless one transistor (1T) dynamic random access memory (DRAM) cell are investigated via device simulator for the first time. The vertical-channel FED type 1T-DRAM cell shows the excellent hold characteristics (100 ms at 358 K of ambient temperature) with large enough read current margin (1 µA/cell) even when silicon pillar diameter (D) is scaled down from 20 to 12 nm. It is also shown that by employing the vertical-channel FED type, maximum lattice temperature in the memory cell due to SHE (T_{\\text{L}}^{\\text{Max}}) can be suppressed to a negligible small value and only reach 300.6 from 300 K ambient temperature due to the low lateral electric field, while the vertical-channel bipolar junction transistor (BJT) type 1T-DRAM shows significant SHE (T_{\\text{L}}^{\\text{Max}} = 330.6 K). Moreover, this excellent thermal characteristic can be maintained even when D is scaled down from 20 to 12 nm.

  19. Crystalline structure and magnetic properties of Fe2CrSi Heusler alloy films: New ferromagnetic material for high-performance magnetic random access memory

    Science.gov (United States)

    Yoshimura, S.; Asano, H.; Nakamura, Y.; Yamaji, K.; Takeda, Y.; Matsui, M.; Ishida, S.; Nozaki, Y.; Matsuyama, K.

    2008-04-01

    A new Heusler alloy, Fe2CrSi, which has high spin polarization (P), low saturation magnetization (Ms), and a low Curie temperature (TC), was investigated in order to fabricate high-performance magnetic tunnel junctions (MTJs) with a high tunnel magnetoresistance ratio and with low critical current for the spin-transfer switching method, or a low switching field for the thermally assisted magnetization reversal technique. The main results are as follows: (1) P and the magnetic moment of Fe2CrSi with an L21 structure were 0.98 and 1.98μB/f.u., respectively, according to density of states calculations. (2) Fe2CrSi films show the (100) orientation with a B2 structure on a MgO substrate upon a thermal treatment with optimum temperature and duration. (3) Fe2CrSi films have Ms and TC values of 385emu /cm3 and 630K, respectively. (4) The (100) oriented epitaxial MTJs are produced with Fe2CrSi films fabricated with the optimized thermal treatment condition. It is found that the Fe2CrSi Heusler alloy films are a suitable ferromagnetic material for high-performance magnetic random access memory.

  20. Soft-error tolerance and energy consumption evaluation of embedded computer with magnetic random access memory in practical systems using computer simulations

    Science.gov (United States)

    Nebashi, Ryusuke; Sakimura, Noboru; Sugibayashi, Tadahiko

    2017-08-01

    We evaluated the soft-error tolerance and energy consumption of an embedded computer with magnetic random access memory (MRAM) using two computer simulators. One is a central processing unit (CPU) simulator of a typical embedded computer system. We simulated the radiation-induced single-event-upset (SEU) probability in a spin-transfer-torque MRAM cell and also the failure rate of a typical embedded computer due to its main memory SEU error. The other is a delay tolerant network (DTN) system simulator. It simulates the power dissipation of wireless sensor network nodes of the system using a revised CPU simulator and a network simulator. We demonstrated that the SEU effect on the embedded computer with 1 Gbit MRAM-based working memory is less than 1 failure in time (FIT). We also demonstrated that the energy consumption of the DTN sensor node with MRAM-based working memory can be reduced to 1/11. These results indicate that MRAM-based working memory enhances the disaster tolerance of embedded computers.