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Sample records for radio mac protocol

  1. Cognitive Radio MAC Protocol for WLAN

    DEFF Research Database (Denmark)

    Zhang, Qi; Fitzek, Frank H.P.; Iversen, Villy Bæk

    2008-01-01

    hole; moreover, it designs dual inband sensing scheme to detect primary user appearance. Additionally, C-CSMA/CA has the advantage to effectively solve the cognitive radio self-coexistence issues in the overlapping CR BSSs scenario. It also realizes station-based dynamic resource selection......To solve the performance degradation issue in current WLAN caused by the crowded unlicensed spectrum, we propose a cognitive radio (CR) media access protocol, C-CSMA/CA. The basic idea is that with cognitive radio techniques the WLAN devices can not only access the legacy WLAN unlicensed spectrum...

  2. A Survey of MAC Protocols for Cognitive Radio Body Area Networks.

    Science.gov (United States)

    Bhandari, Sabin; Moh, Sangman

    2015-04-20

    The advancement in electronics, wireless communications and integrated circuits has enabled the development of small low-power sensors and actuators that can be placed on, in or around the human body. A wireless body area network (WBAN) can be effectively used to deliver the sensory data to a central server, where it can be monitored, stored and analyzed. For more than a decade, cognitive radio (CR) technology has been widely adopted in wireless networks, as it utilizes the available spectra of licensed, as well as unlicensed bands. A cognitive radio body area network (CRBAN) is a CR-enabled WBAN. Unlike other wireless networks, CRBANs have specific requirements, such as being able to automatically sense their environments and to utilize unused, licensed spectra without interfering with licensed users, but existing protocols cannot fulfill them. In particular, the medium access control (MAC) layer plays a key role in cognitive radio functions, such as channel sensing, resource allocation, spectrum mobility and spectrum sharing. To address various application-specific requirements in CRBANs, several MAC protocols have been proposed in the literature. In this paper, we survey MAC protocols for CRBANs. We then compare the different MAC protocols with one another and discuss challenging open issues in the relevant research.

  3. SACRB-MAC: A High-Capacity MAC Protocol for Cognitive Radio Sensor Networks in Smart Grid.

    Science.gov (United States)

    Yang, Zhutian; Shi, Zhenguo; Jin, Chunlin

    2016-03-31

    The Cognitive Radio Sensor Network (CRSN) is considered as a viable solution to enhance various aspects of the electric power grid and to realize a smart grid. However, several challenges for CRSNs are generated due to the harsh wireless environment in a smart grid. As a result, throughput and reliability become critical issues. On the other hand, the spectrum aggregation technique is expected to play an important role in CRSNs in a smart grid. By using spectrum aggregation, the throughput of CRSNs can be improved efficiently, so as to address the unique challenges of CRSNs in a smart grid. In this regard, we proposed Spectrum Aggregation Cognitive Receiver-Based MAC (SACRB-MAC), which employs the spectrum aggregation technique to improve the throughput performance of CRSNs in a smart grid. Moreover, SACRB-MAC is a receiver-based MAC protocol, which can provide a good reliability performance. Analytical and simulation results demonstrate that SACRB-MAC is a promising solution for CRSNs in a smart grid.

  4. Potential of Wake-Up Radio-Based MAC Protocols for Implantable Body Sensor Networks (IBSN—A Survey

    Directory of Open Access Journals (Sweden)

    Vignesh Raja Karuppiah Ramachandran

    2016-11-01

    Full Text Available With the advent of nano-technology, medical sensors and devices are becoming highly miniaturized. Consequently, the number of sensors and medical devices being implanted to accurately monitor and diagnose a disease is increasing. By measuring the symptoms and controlling a medical device as close as possible to the source, these implantable devices are able to save lives. A wireless link between medical sensors and implantable medical devices is essential in the case of closed-loop medical devices, in which symptoms of the diseases are monitored by sensors that are not placed in close proximity of the therapeutic device. Medium Access Control (MAC is crucial to make it possible for several medical devices to communicate using a shared wireless medium in such a way that minimum delay, maximum throughput, and increased network life-time are guaranteed. To guarantee this Quality of Service (QoS, the MAC protocols control the main sources of limited resource wastage, namely the idle-listening, packet collisions, over-hearing, and packet loss. Traditional MAC protocols designed for body sensor networks are not directly applicable to Implantable Body Sensor Networks (IBSN because of the dynamic nature of the radio channel within the human body and the strict QoS requirements of IBSN applications. Although numerous MAC protocols are available in the literature, the majority of them are designed for Body Sensor Network (BSN and Wireless Sensor Network (WSN. To the best of our knowledge, there is so far no research paper that explores the impact of these MAC protocols specifically for IBSN. MAC protocols designed for implantable devices are still in their infancy and one of their most challenging objectives is to be ultra-low-power. One of the technological solutions to achieve this objective so is to integrate the concept of Wake-up radio (WuR into the MAC design. In this survey, we present a taxonomy of MAC protocols based on their use of Wu

  5. Implantable Body Sensor Network MAC Protocols Using Wake-up Radio – Evaluation in Animal Tissue

    NARCIS (Netherlands)

    Karuppiah Ramachandran, Vignesh Raja; van der Zwaag, B.J.; Meratnia, Nirvana; Havinga, Paul J.M.

    Applications of implantable sensor networks in the health-care industry have increased tremendously over the last decade. There are different types of medium access control (MAC) protocols that are designed for implantable body sensor networks, using different physical layer technologies such as

  6. Mac protocols for cyber-physical systems

    CERN Document Server

    Xia, Feng

    2015-01-01

    This book provides a literature review of various wireless MAC protocols and techniques for achieving real-time and reliable communications in the context of cyber-physical systems (CPS). The evaluation analysis of IEEE 802.15.4 for CPS therein will give insights into configuration and optimization of critical design parameters of MAC protocols. In addition, this book also presents the design and evaluation of an adaptive MAC protocol for medical CPS, which exemplifies how to facilitate real-time and reliable communications in CPS by exploiting IEEE 802.15.4 based MAC protocols. This book wil

  7. Mac protocols for wireless sensor network (wsn): a comparative study

    International Nuclear Information System (INIS)

    Arshad, J.; Akram, Q.; Saleem, Y.

    2014-01-01

    Data communication between nodes is carried out under Medium Access Control (MAC) protocol which is defined at data link layer. The MAC protocols are responsible to communicate and coordinate between nodes according to the defined standards in WSN (Wireless Sensor Networks). The design of a MAC protocol should also address the issues of energy efficiency and transmission efficiency. There are number of MAC protocols that exist in the literature proposed for WSN. In this paper, nine MAC protocols which includes S-MAC, T-MAC, Wise-MAC, Mu-MAC, Z-MAC, A-MAC, D-MAC, B-MAC and B-MAC+ for WSN have been explored, studied and analyzed. These nine protocols are classified in contention based and hybrid (combination of contention and schedule based) MAC protocols. The goal of this comparative study is to provide a basis for MAC protocols and to highlight different mechanisms used with respect to parameters for the evaluation of energy and transmission efficiency in WSN. This study also aims to give reader a better understanding of the concepts, processes and flow of information used in these MAC protocols for WSN. A comparison with respect to energy reservation scheme, idle listening avoidance, latency, fairness, data synchronization, and throughput maximization has been presented. It was analyzed that contention based MAC protocols are less energy efficient as compared to hybrid MAC protocols. From the analysis of contention based MAC protocols in term of energy consumption, it was being observed that protocols based on preamble sampling consume lesser energy than protocols based on static or dynamic sleep schedule. (author)

  8. Power Saving MAC Protocols for WSNs and Optimization of S-MAC Protocol

    Directory of Open Access Journals (Sweden)

    Simarpreet Kaur

    2012-11-01

    Full Text Available Low power MAC protocols have received a lot of consideration in the last few years because of their influence on the lifetime of wireless sensor networks. Since, sensors typically operate on batteries, replacement of which is often difficult. A lot of work has been done to minimize the energy expenditure and prolong the sensor lifetime through energy efficient designs, across layers. Meanwhile, the sensor network should be able to maintain a certain throughput in order to fulfill the QoS requirements of the end user, and to ensure the constancy of the network. This paper introduces different types of MAC protocols used for WSNs and proposes S‐MAC, a Medium‐Access Control protocol designed for Wireless Sensor Networks. S‐MAC uses a few innovative techniques to reduce energy consumption and support selfconfiguration. A new protocol is suggested to improve the energy efficiency, latency and throughput of existing MAC protocol for WSNs. A modification of the protocol is then proposed to eliminate the need for some nodes to stay awake longer than the other nodes which improves the energy efficiency, latency and throughput and hence increases the life span of a wireless sensor network.

  9. Analyzing the effect of routing protocols on media access control protocols in radio networks

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, C. L. (Christopher L.); Drozda, M. (Martin); Marathe, A. (Achla); Marathe, M. V. (Madhav V.)

    2002-01-01

    We study the effect of routing protocols on the performance of media access control (MAC) protocols in wireless radio networks. Three well known MAC protocols: 802.11, CSMA, and MACA are considered. Similarly three recently proposed routing protocols: AODV, DSR and LAR scheme 1 are considered. The experimental analysis was carried out using GloMoSim: a tool for simulating wireless networks. The main focus of our experiments was to study how the routing protocols affect the performance of the MAC protocols when the underlying network and traffic parameters are varied. The performance of the protocols was measured w.r.t. five important parameters: (i) number of received packets, (ii) average latency of each packet, (iii) throughput (iv) long term fairness and (v) number of control packets at the MAC layer level. Our results show that combinations of routing and MAC protocols yield varying performance under varying network topology and traffic situations. The result has an important implication; no combination of routing protocol and MAC protocol is the best over all situations. Also, the performance analysis of protocols at a given level in the protocol stack needs to be studied not locally in isolation but as a part of the complete protocol stack. A novel aspect of our work is the use of statistical technique, ANOVA (Analysis of Variance) to characterize the effect of routing protocols on MAC protocols. This technique is of independent interest and can be utilized in several other simulation and empirical studies.

  10. Emergency Handling for MAC Protocol in Human Body Communication

    Directory of Open Access Journals (Sweden)

    Kwon Youngmi

    2011-01-01

    Full Text Available The human body communication (HBC is a technology that enables short range data communication using the human body as a medium, like an electrical wire. Thus it removes the need for a traditional antenna. HBC may be used as a type of data communication in body area network (BAN, while the devices are being in contact with body. One of important issues in BAN is an emergency alarm because it may be closely related to human life. For emergency data communication, the most critical factor is the time constraint. IEEE 802.15.6 specifies that the emergency alarm for the BAN must be notified in less than 1 sec and must provide prioritization mechanisms for emergency traffic and notification. As one type of BAN, the HBC must follow this recommendation, too. Existing emergency handling methods in BAN are based on the carrier sensing capability on radio frequencies to detect the status of channels. However, PHY protocol in HBC does not provide the carrier sensing. So the previous methods are not well suitable for HBC directly. Additionally, in the environment that the emergency rate is very low, the allocation of dedicated slot(s for emergency in each superframe is very wasteful. In this work, we proposed specific emergency handling operation for human body communication's medium access control (HBC-MAC protocol to meet the emergency requirements for BAN. We also showed the optimal number of emergency slots for the various combinations of beacon intervals and emergency rates.

  11. A Mac Protocol Implementation for Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Jamila Bhar

    2015-01-01

    Full Text Available IEEE 802.15.4 is an important standard for Low Rate Wireless Personal Area Network (LRWPAN. The IEEE 802.15.4 presents a flexible MAC protocol that provides good efficiency for data transmission by adapting its parameters according to characteristics of different applications. In this research work, some restrictions of this standard are explained and an improvement of traffic efficiency by optimizing MAC layer is proposed. Implementation details for several blocks of communication system are carefully modeled. The protocol implementation is done using VHDL language. The analysis gives a full understanding of the behavior of the MAC protocol with regard to backoff delay, data loss probability, congestion probability, slot effectiveness, and traffic distribution for terminals. Two ideas are proposed and tested to improve efficiency of CSMA/CA mechanism for IEEE 802.15.4 MAC Layer. Primarily, we dynamically adjust the backoff exponent (BE according to queue level of each node. Secondly, we vary the number of consecutive clear channel assessment (CCA for packet transmission. We demonstrate also that slot compensation provided by the enhanced MAC protocol can greatly avoid unused slots. The results show the significant improvements expected by our approach among the IEEE 802.15.4 MAC standards. Synthesis results show also hardware performances of our proposed architecture.

  12. Connectivity-Based Reliable Multicast MAC Protocol for IEEE 802.11 Wireless LANs

    Directory of Open Access Journals (Sweden)

    Woo-Yong Choi

    2009-01-01

    Full Text Available We propose the efficient reliable multicast MAC protocol based on the connectivity information among the recipients. Enhancing the BMMM (Batch Mode Multicast MAC protocol, the reliable multicast MAC protocol significantly reduces the RAK (Request for ACK frame transmissions in a reasonable computational time and enhances the MAC performance. By the analytical performance analysis, the throughputs of the BMMM protocol and our proposed MAC protocol are derived. Numerical examples show that our proposed MAC protocol increases the reliable multicast MAC performance for IEEE 802.11 wireless LANs.

  13. A Very Low Power MAC (VLPM Protocol for Wireless Body Area Networks

    Directory of Open Access Journals (Sweden)

    Kyung Sup Kwak

    2011-03-01

    Full Text Available Wireless Body Area Networks (WBANs consist of a limited number of battery operated nodes that are used to monitor the vital signs of a patient over long periods of time without restricting the patient’s movements. They are an easy and fast way to diagnose the patient’s status and to consult the doctor. Device as well as network lifetime are among the most important factors in a WBAN. Prolonging the lifetime of the WBAN strongly depends on controlling the energy consumption of sensor nodes. To achieve energy efficiency, low duty cycle MAC protocols are used, but for medical applications, especially in the case of pacemakers where data have time-limited relevance, these protocols increase latency which is highly undesirable and leads to system instability. In this paper, we propose a low power MAC protocol (VLPM based on existing wakeup radio approaches which reduce energy consumption as well as improving the response time of a node. We categorize the traffic into uplink and downlink traffic. The nodes are equipped with both a low power wake-up transmitter and receiver. The low power wake-up receiver monitors the activity on channel all the time with a very low power and keeps the MCU (Micro Controller Unit along with main radio in sleep mode. When a node [BN or BNC (BAN Coordinator] wants to communicate with another node, it uses the low-power radio to send a wakeup packet, which will prompt the receiver to power up its primary radio to listen for the message that follows shortly. The wake-up packet contains the desired node’s ID along with some other information to let the targeted node to wake-up and take part in communication and let all other nodes to go to sleep mode quickly. The VLPM protocol is proposed for applications having low traffic conditions. For high traffic rates, optimization is needed. Analytical results show that the proposed protocol outperforms both synchronized and unsynchronized MAC protocols like T-MAC, SCP-MAC, B-MAC

  14. Traffic Adaptive MAC Protocols in Wireless Body Area Networks

    Directory of Open Access Journals (Sweden)

    Farhan Masud

    2017-01-01

    Full Text Available In Wireless Body Area Networks (WBANs, every healthcare application that is based on physical sensors is responsible for monitoring the vital signs data of patient. WBANs applications consist of heterogeneous and dynamic traffic loads. Routine patient’s observation is described as low-load traffic while an alarming situation that is unpredictable by nature is referred to as high-load traffic. This paper offers a thematic review of traffic adaptive Medium Access Control (MAC protocols in WBANs. First, we have categorized them based on their goals, methods, and metrics of evaluation. The Zigbee standard IEEE 802.15.4 and the baseline MAC IEEE 802.15.6 are also reviewed in terms of traffic adaptive approaches. Furthermore, a comparative analysis of the protocols is made and their performances are analyzed in terms of delay, packet delivery ratio (PDR, and energy consumption. The literature shows that no review work has been done on traffic adaptive MAC protocols in WBANs. This review work, therefore, could add enhancement to traffic adaptive MAC protocols and will stimulate a better way of solving the traffic adaptivity problem.

  15. Directional Medium Access Control (MAC Protocols in Wireless Ad Hoc and Sensor Networks: A Survey

    Directory of Open Access Journals (Sweden)

    David Tung Chong Wong

    2015-06-01

    Full Text Available This survey paper presents the state-of-the-art directional medium access control (MAC protocols in wireless ad hoc and sensor networks (WAHSNs. The key benefits of directional antennas over omni-directional antennas are longer communication range, less multipath interference, more spatial reuse, more secure communications, higher throughput and reduced latency. However, directional antennas lead to single-/multi-channel directional hidden/exposed terminals, deafness and neighborhood, head-of-line blocking, and MAC-layer capture which need to be overcome. Addressing these problems and benefits for directional antennas to MAC protocols leads to many classes of directional MAC protocols in WAHSNs. These classes of directional MAC protocols presented in this survey paper include single-channel, multi-channel, cooperative and cognitive directional MACs. Single-channel directional MAC protocols can be classified as contention-based or non-contention-based or hybrid-based, while multi-channel directional MAC protocols commonly use a common control channel for control packets/tones and one or more data channels for directional data transmissions. Cooperative directional MAC protocols improve throughput in WAHSNs via directional multi-rate/single-relay/multiple-relay/two frequency channels/polarization, while cognitive directional MAC protocols leverage on conventional directional MAC protocols with new twists to address dynamic spectrum access. All of these directional MAC protocols are the pillars for the design of future directional MAC protocols in WAHSNs.

  16. ASAP: A MAC Protocol for Dense and Time-Constrained RFID Systems

    Directory of Open Access Journals (Sweden)

    Kyounghwan Lee

    2007-08-01

    Full Text Available We introduce a novel medium access control (MAC protocol for radio frequency identification (RFID systems which exploits the statistical information collected at the reader. The protocol, termed adaptive slotted ALOHA protocol (ASAP, is motivated by the need to significantly improve the total read time performance of the currently suggested MAC protocols for RFID systems. In order to accomplish this task, ASAP estimates the dynamic tag population and adapts the frame size in the subsequent round via a simple policy that maximizes an appropriately defined efficiency function. We demonstrate that ASAP provides significant improvement in total read time performance over the current RFID MAC protocols. We next extend the design to accomplish reliable performance of ASAP in realistic scenarios such as the existence of constraints on frame size, and mobile RFID systems where tags move at constant velocity in the reader's field. We also consider the case where tags may fail to respond because of a physical breakdown or a temporary malfunction, and show the robustness in those scenarios as well.

  17. Design of an autonomous decentralized MAC protocol for wireless sensor networks

    NARCIS (Netherlands)

    van Hoesel, L.F.W.; Dal Pont, L.; Havinga, Paul J.M.

    In this document the design of a MAC protocol for wireless sensor networks is discussed. The autonomous decentralized TDMA based MAC protocol minimizes power consumtion by efficiency implementing unicast/omnicast, scheduled rendezvous times and wakeup calls. The MAC protocol is an ongoing research

  18. TreeMAC: Localized TDMA MAC protocol for real-time high-data-rate sensor networks

    Science.gov (United States)

    Song, W.-Z.; Huang, R.; Shirazi, B.; Husent, R.L.

    2009-01-01

    Earlier sensor network MAC protocols focus on energy conservation in low-duty cycle applications, while some recent applications involve real-time high-data-rate signals. This motivates us to design an innovative localized TDMA MAC protocol to achieve high throughput and low congestion in data collection sensor networks, besides energy conservation. TreeMAC divides a time cycle into frames and frame into slots. Parent determines children's frame assigmnent based on their relative bandwidth demand, and each node calculates its own slot assignment based on its hop-count to the sink. This innovative 2-dimensional frame-slot assignment algorithm has the following nice theory properties. Firstly, given any node, at any time slot, there is at most one active sender in its neighborhood (includ ing itself). Secondly, the packet scheduling with TreelMAC is bufferless, which therefore minimizes the probability of network congestion. Thirdly, the data throughput to gateway is at least 1/3 of the optimum assuming reliable links. Our experiments on a 24 node test bed demonstrate that TreeMAC protocol significantly improves network throughput and energy efficiency, by comparing to the TinyOS's default CSMA MAC protocol and a recent TDMA MAC protocol Funneling-MAC[8]. ?? 2009 IEEE.

  19. Intelligent Cooperative MAC Protocol for Balancing Energy Consumption

    Science.gov (United States)

    Wu, S.; Liu, K.; Huang, B.; Liu, F.

    To extend the lifetime of wireless sensor networks, we proposed an intelligent balanced energy consumption cooperative MAC protocol (IBEC-CMAC) based on the multi-node cooperative transmission model. The protocol has priority to access high-quality channels for reducing energy consumption of each transmission. It can also balance the energy consumption among cooperative nodes by using high residual energy nodes instead of excessively consuming some node's energy. Simulation results show that IBEC-CMAC can obtain longer network lifetime and higher energy utilization than direct transmission.

  20. Autonomous Power Control MAC Protocol for Mobile Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available Battery energy limitation has become a performance bottleneck for mobile ad hoc networks. IEEE 802.11 has been adopted as the current standard MAC protocol for ad hoc networks. However, it was developed without considering energy efficiency. To solve this problem, many modifications on IEEE 802.11 to incorporate power control have been proposed in the literature. The main idea of these power control schemes is to use a maximum possible power level for transmitting RTS/CTS and the lowest acceptable power for sending DATA/ACK. However, these schemes may degrade network throughput and reduce the overall energy efficiency of the network. This paper proposes autonomous power control MAC protocol (APCMP, which allows mobile nodes dynamically adjusting power level for transmitting DATA/ACK according to the distances between the transmitter and its neighbors. In addition, the power level for transmitting RTS/CTS is also adjustable according to the power level for DATA/ACK packets. In this paper, the performance of APCMP protocol is evaluated by simulation and is compared with that of other protocols.

  1. Medium Access Control Protocols for Cognitive Radio Ad Hoc Networks: A Survey

    Directory of Open Access Journals (Sweden)

    Mahdi Zareei

    2017-09-01

    Full Text Available New wireless network paradigms will demand higher spectrum use and availability to cope with emerging data-hungry devices. Traditional static spectrum allocation policies cause spectrum scarcity, and new paradigms such as Cognitive Radio (CR and new protocols and techniques need to be developed in order to have efficient spectrum usage. Medium Access Control (MAC protocols are accountable for recognizing free spectrum, scheduling available resources and coordinating the coexistence of heterogeneous systems and users. This paper provides an ample review of the state-of-the-art MAC protocols, which mainly focuses on Cognitive Radio Ad Hoc Networks (CRAHN. First, a description of the cognitive radio fundamental functions is presented. Next, MAC protocols are divided into three groups, which are based on their channel access mechanism, namely time-slotted protocol, random access protocol and hybrid protocol. In each group, a detailed and comprehensive explanation of the latest MAC protocols is presented, as well as the pros and cons of each protocol. A discussion on future challenges for CRAHN MAC protocols is included with a comparison of the protocols from a functional perspective.

  2. TMAC: Timestamp-Ordered MAC Protocol for Wireless Mesh Networks

    KAUST Repository

    Nawab, Faisal

    2011-05-01

    Wireless Mesh Networks (WMNs) have emerged to meet a need for a self-organized and self-configured multi-hop wireless network infrastructure. Low cost infrastructure and ease of deployment have made WMNs an attractive technology for last mile access. However, 802.11 based WMNs are subject to serious fairness issues. With backlogged TCP traffic, nodes which are two or more hops away from the gateway are subject to starvation, while the one-hop away node saturates the channel with its own local traffic. We study the interactions of TCP and IEEE 802.11 MAC in WMNs to aid us in understanding and overcoming the unfairness problem. We propose a Markov chain to capture the behavior of TCP sessions, particularly the impact on network throughput performance due to the effect of queue utilization and packet relaying. A closed form solution is derived to numerically derive the throughput. Based on the developed model, we propose a distributed MAC protocol called Timestamp-ordered MAC (TMAC), aiming to alleviate the unfairness problem in WMNs via a manipulative per-node scheduling mechanism which takes advantage of the age of each packet as a priority metric. Simulation is conducted to validate our model and to illustrate the fairness characteristics of TMAC. Our results show that TMAC achieves excellent resource allocation fairness while maintaining above 90% of maximum link capacity in parking lot and large grid topologies. Our work illuminates the factors affecting TCP fairness in WMNs. Our theoretical and empirical findings can be used in future research to develop more fairness-aware protocols for WMNs.

  3. A Service Differentiated MAC Protocol for OFDM/TDMA Wireless Systems

    Institute of Scientific and Technical Information of China (English)

    WANG Ying; ZHANG Ping

    2005-01-01

    This paper proposes a Service Differentiated-Dynamic Slotted Multiple Access (SD-DSMA) protocol with QoS guarantee. The Media Access Control (MAC) frame format is variable according to the traffic of uplink and downlink and the traffic of control and data. In addition, the services are divided into two categories, Guaranteed Bandwidth (GB) and Best Effort (BE). Uplink control message slots are designed for the GB users to reduce contention. Taking into consideration the techniques in physical layer, a two-Dimensional Radio Resource Allocation (2-D RRA) method is proposed. The 2-D RRA is an efficient way to allocate radio resources for multi-cell, multi-user OFDM/TDMA system as it takes into consideration both the channel condition and the co-channel interference. The piggyback mechanism and fair scheduling algorithm are adopted for GB services, and the max C/I scheduling algorithm is used for BE services. The simulation results show that the proposed MAC protocol has better performance in terms of delay, probability of successful access request.

  4. Optimizing the MAC Protocol in Localization Systems Based on IEEE 802.15.4 Networks

    Directory of Open Access Journals (Sweden)

    Juan J. Pérez-Solano

    2017-07-01

    Full Text Available Radio frequency signals are commonly used in the development of indoor localization systems. The infrastructure of these systems includes some beacons placed at known positions that exchange radio packets with users to be located. When the system is implemented using wireless sensor networks, the wireless transceivers integrated in the network motes are usually based on the IEEE 802.15.4 standard. But, the CSMA-CA, which is the basis for the medium access protocols in this category of communication systems, is not suitable when several users want to exchange bursts of radio packets with the same beacon to acquire the radio signal strength indicator (RSSI values needed in the location process. Therefore, new protocols are necessary to avoid the packet collisions that appear when multiple users try to communicate with the same beacons. On the other hand, the RSSI sampling process should be carried out very quickly because some systems cannot tolerate a large delay in the location process. This is even more important when the RSSI sampling process includes measures with different signal power levels or frequency channels. The principal objective of this work is to speed up the RSSI sampling process in indoor localization systems. To achieve this objective, the main contribution is the proposal of a new MAC protocol that eliminates the medium access contention periods and decreases the number of packet collisions to accelerate the RSSI collection process. Moreover, the protocol increases the overall network throughput taking advantage of the frequency channel diversity. The presented results show the suitability of this protocol for reducing the RSSI gathering delay and increasing the network throughput in simulated and real environments.

  5. Optimizing the MAC Protocol in Localization Systems Based on IEEE 802.15.4 Networks.

    Science.gov (United States)

    Pérez-Solano, Juan J; Claver, Jose M; Ezpeleta, Santiago

    2017-07-06

    Radio frequency signals are commonly used in the development of indoor localization systems. The infrastructure of these systems includes some beacons placed at known positions that exchange radio packets with users to be located. When the system is implemented using wireless sensor networks, the wireless transceivers integrated in the network motes are usually based on the IEEE 802.15.4 standard. But, the CSMA-CA, which is the basis for the medium access protocols in this category of communication systems, is not suitable when several users want to exchange bursts of radio packets with the same beacon to acquire the radio signal strength indicator (RSSI) values needed in the location process. Therefore, new protocols are necessary to avoid the packet collisions that appear when multiple users try to communicate with the same beacons. On the other hand, the RSSI sampling process should be carried out very quickly because some systems cannot tolerate a large delay in the location process. This is even more important when the RSSI sampling process includes measures with different signal power levels or frequency channels. The principal objective of this work is to speed up the RSSI sampling process in indoor localization systems. To achieve this objective, the main contribution is the proposal of a new MAC protocol that eliminates the medium access contention periods and decreases the number of packet collisions to accelerate the RSSI collection process. Moreover, the protocol increases the overall network throughput taking advantage of the frequency channel diversity. The presented results show the suitability of this protocol for reducing the RSSI gathering delay and increasing the network throughput in simulated and real environments.

  6. A Fair Cooperative MAC Protocol in IEEE 802.11 WLAN

    Directory of Open Access Journals (Sweden)

    Seyed Davoud Mousavi

    2018-05-01

    Full Text Available Cooperative communication techniques have recently enabled wireless technologies to overcome their challenges. The main objective of these techniques is to improve resource allocation. In this paper, we propose a new protocol in medium access control (MAC of the IEEE 802.11 standard. In our new protocol, which is called Fair Cooperative MAC (FC-MAC, every relay node participates in cooperation proportionally to its provided cooperation gain. This technique improves network resource allocation by exploiting the potential capacity of all relay candidates. Simulation results demonstrate that the FC-MAC protocol presents better performance in terms of throughput, fairness, and network lifetime.

  7. MAC Protocol for Ad Hoc Networks Using a Genetic Algorithm

    Science.gov (United States)

    Elizarraras, Omar; Panduro, Marco; Méndez, Aldo L.

    2014-01-01

    The problem of obtaining the transmission rate in an ad hoc network consists in adjusting the power of each node to ensure the signal to interference ratio (SIR) and the energy required to transmit from one node to another is obtained at the same time. Therefore, an optimal transmission rate for each node in a medium access control (MAC) protocol based on CSMA-CDMA (carrier sense multiple access-code division multiple access) for ad hoc networks can be obtained using evolutionary optimization. This work proposes a genetic algorithm for the transmission rate election considering a perfect power control, and our proposition achieves improvement of 10% compared with the scheme that handles the handshaking phase to adjust the transmission rate. Furthermore, this paper proposes a genetic algorithm that solves the problem of power combining, interference, data rate, and energy ensuring the signal to interference ratio in an ad hoc network. The result of the proposed genetic algorithm has a better performance (15%) compared to the CSMA-CDMA protocol without optimizing. Therefore, we show by simulation the effectiveness of the proposed protocol in terms of the throughput. PMID:25140339

  8. MAC Protocol for Ad Hoc Networks Using a Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Omar Elizarraras

    2014-01-01

    Full Text Available The problem of obtaining the transmission rate in an ad hoc network consists in adjusting the power of each node to ensure the signal to interference ratio (SIR and the energy required to transmit from one node to another is obtained at the same time. Therefore, an optimal transmission rate for each node in a medium access control (MAC protocol based on CSMA-CDMA (carrier sense multiple access-code division multiple access for ad hoc networks can be obtained using evolutionary optimization. This work proposes a genetic algorithm for the transmission rate election considering a perfect power control, and our proposition achieves improvement of 10% compared with the scheme that handles the handshaking phase to adjust the transmission rate. Furthermore, this paper proposes a genetic algorithm that solves the problem of power combining, interference, data rate, and energy ensuring the signal to interference ratio in an ad hoc network. The result of the proposed genetic algorithm has a better performance (15% compared to the CSMA-CDMA protocol without optimizing. Therefore, we show by simulation the effectiveness of the proposed protocol in terms of the throughput.

  9. Bit Level Synchronized MAC Protocol for Multireader RFID Networks

    Directory of Open Access Journals (Sweden)

    Namboodiri Vinod

    2010-01-01

    Full Text Available The operation of multiple RFID readers in close proximity results in interference between the readers. This issue is termed the reader collision problem and cannot always be solved by assigning them to different frequency channels due to technical and regulatory limitations. The typical solution is to separate the operation of such readers across time. This sequential operation, however, results in a long delay to identify all tags. We present a bit level synchronized (BLSync MAC protocol for multi-reader RFID networks that allows multiple readers to operate simultaneously on the same frequency channel. The BLSync protocol solves the reader collision problem by allowing all readers to transmit the same query at the same time. We analyze the performance of using the BLSync protocol and demonstrate benefits of 40%–50% in terms of tag reading delay for most settings. The benefits of BLSync, first demonstrated through analysis, are then validated and quantified through simulations on realistic reader-tag layouts.

  10. Optimization and Verification of the TR-MAC Protocol for Wireless Sensor Networks

    NARCIS (Netherlands)

    Morshed, S.; Heijenk, Geert

    2015-01-01

    Energy-efficiency is an important requirement in the design of communication protocols for wireless sensor networks (WSN). TR-MAC is an energy-efficient medium access control (MAC) layer protocol for low power WSN that exploits transmitted-reference (TR) modulation in the physical layer. The

  11. Power-Controlled MAC Protocols with Dynamic Neighbor Prediction for Ad hoc Networks

    Institute of Scientific and Technical Information of China (English)

    LI Meng; ZHANG Lin; XIAO Yong-kang; SHAN Xiu-ming

    2004-01-01

    Energy and bandwidth are the scarce resources in ad hoc networks because most of the mobile nodes are battery-supplied and share the exclusive wireless medium. Integrating the power control into MAC protocol is a promising technique to fully exploit these precious resources of ad hoc wireless networks. In this paper, a new intelligent power-controlled Medium Access Control (MAC) (iMAC) protocol with dynamic neighbor prediction is proposed. Through the elaborate design of the distributed transmit-receive strategy of mobile nodes, iMAC greatly outperforms the prevailing IEEE 802.11 MAC protocols in not only energy conservation but also network throughput. Using the Dynamic Neighbor Prediction (DNP), iMAC performs well in mobile scenes. To the best of our knowledge, iMAC is the first protocol that considers the performance deterioration of power-controlled MAC protocols in mobile scenes and then proposes a solution. Simulation results indicate that DNP is important and necessary for power-controlled MAC protocols in mobile ad hoc networks.

  12. TR-MAC: an energy-efficient MAC protocol for wireless sensor networks exploiting noise-based transmitted reference modulation

    NARCIS (Netherlands)

    Morshed, S.; Dimitrova, D.C.; Brogle, M.; Braun, T.; Heijenk, Gerhard J.

    Energy-constrained behavior of sensor nodes is one of the most important criteria for successful deployment of wireless sensor net- works. The medium access control (MAC) protocol determines the time a sensor node transceiver spends listening or transmitting, and hence the energy consumption of the

  13. Reliable Multicast MAC Protocol for IEEE 802.11 Wireless LANs with Extended Service Range

    Science.gov (United States)

    Choi, Woo-Yong

    2011-11-01

    In this paper, we propose the efficient reliable multicast MAC protocol by which the AP (Access Point) can transmit reliably its multicast data frames to the recipients in the AP's one-hop or two-hop transmission range. The AP uses the STAs (Stations) that are directly associated with itself as the relays for the data delivery to the remote recipients that cannot be reached directly from itself. Based on the connectivity information among the recipients, the reliable multicast MAC protocol optimizes the number of the RAK (Request for ACK) frame transmissions in a reasonable computational time. Numerical examples show that our proposed MAC protocol significantly enhances the MAC performance compared with the BMMM (Batch Mode Multicast MAC) protocol that is extended to support the recipients that are in the AP's one-hop or two-hop transmission range in IEEE 802.11 wireless LANs.

  14. Experimental Evaluation of Simulation Abstractions for Wireless Sensor Network MAC Protocols

    Directory of Open Access Journals (Sweden)

    G. P. Halkes

    2010-01-01

    Full Text Available The evaluation of MAC protocols for Wireless Sensor Networks (WSNs is often performed through simulation. These simulations necessarily abstract away from reality in many ways. However, the impact of these abstractions on the results of the simulations has received only limited attention. Moreover, many studies on the accuracy of simulation have studied either the physical layer and per link effects or routing protocol effects. To the best of our knowledge, no other work has focused on the study of the simulation abstractions with respect to MAC protocol performance. In this paper, we present the results of an experimental study of two often used abstractions in the simulation of WSN MAC protocols. We show that a simple SNR-based reception model can provide quite accurate results for metrics commonly used to evaluate MAC protocols. Furthermore, we provide an analysis of what the main sources of deviation are and thereby how the simulations can be improved to provide even better results.

  15. A new architecture and MAC protocol for fully flexible hybrid WDM/TDM PON

    NARCIS (Netherlands)

    Das, G.; Lannoo, B.; Jung, H.D.; Koonen, A.M.J.; Colle, D.; Pickavet, M.; Demeester, P.

    2009-01-01

    In this paper we propose a novel architecture and MAC protocol for a scalable, cost effective WDM / TDM PON providing fully flexible dynamic bandwidth allocation for upstream and downstream data transmission.

  16. Evaluation of video transmission of MAC protocols in wireless sensor network

    Science.gov (United States)

    Maulidin, Mahmuddin, M.; Kamaruddin, L. M.; Elsaikh, Mohamed

    2016-08-01

    Wireless Sensor Network (WSN) is a wireless network which consists of sensor nodes scattered in a particular area which are used to monitor physical or environment condition. Each node in WSN is also scattered in sensor field, so an appropriate scheme of MAC protocol should have to develop communication link for data transferring. Video transmission is one of the important applications for the future that can be transmitted with low aspect in side of cost and also power consumption. In this paper, comparison of five different MAC WSN protocol for video transmission namely IEEE 802.11 standard, IEEE 802.15.4 standard, CSMA/CA, Berkeley-MAC, and Lightweight-MAC protocol are studied. Simulation experiment has been conducted in OMNeT++ with INET network simulator software to evaluate the performance. Obtained results indicate that IEEE 802.11 works better than other protocol in term of packet delivery, throughput, and latency.

  17. Corrections to "Connectivity-Based Reliable Multicast MAC Protocol for IEEE 802.11 Wireless LANs"

    Directory of Open Access Journals (Sweden)

    Choi Woo-Yong

    2010-01-01

    Full Text Available We have found the errors in the throughput formulae presented in our paper "Connectivity-based reliable multicast MAC protocol for IEEE 802.11 wireless LANs". We provide the corrected formulae and numerical results.

  18. A Priority-Based Adaptive MAC Protocol for Wireless Body Area Networks

    Directory of Open Access Journals (Sweden)

    Sabin Bhandari

    2016-03-01

    Full Text Available In wireless body area networks (WBANs, various sensors and actuators are placed on/inside the human body and connected wirelessly. WBANs have specific requirements for healthcare and medical applications, hence, standard protocols like the IEEE 802.15.4 cannot fulfill all the requirements. Consequently, many medium access control (MAC protocols, mostly derived from the IEEE 802.15.4 superframe structure, have been studied. Nevertheless, they do not support a differentiated quality of service (QoS for the various forms of traffic coexisting in a WBAN. In particular, a QoS-aware MAC protocol is essential for WBANs operating in the unlicensed Industrial, Scientific, and Medical (ISM bands, because different wireless services like Bluetooth, WiFi, and Zigbee may coexist there and cause severe interference. In this paper, we propose a priority-based adaptive MAC (PA-MAC protocol for WBANs in unlicensed bands, which allocates time slots dynamically, based on the traffic priority. Further, multiple channels are effectively utilized to reduce access delays in a WBAN, in the presence of coexisting systems. Our performance evaluation results show that the proposed PA-MAC outperforms the IEEE 802.15.4 MAC and the conventional priority-based MAC in terms of the average transmission time, throughput, energy consumption, and data collision ratio.

  19. A Priority-Based Adaptive MAC Protocol for Wireless Body Area Networks.

    Science.gov (United States)

    Bhandari, Sabin; Moh, Sangman

    2016-03-18

    In wireless body area networks (WBANs), various sensors and actuators are placed on/inside the human body and connected wirelessly. WBANs have specific requirements for healthcare and medical applications, hence, standard protocols like the IEEE 802.15.4 cannot fulfill all the requirements. Consequently, many medium access control (MAC) protocols, mostly derived from the IEEE 802.15.4 superframe structure, have been studied. Nevertheless, they do not support a differentiated quality of service (QoS) for the various forms of traffic coexisting in a WBAN. In particular, a QoS-aware MAC protocol is essential for WBANs operating in the unlicensed Industrial, Scientific, and Medical (ISM) bands, because different wireless services like Bluetooth, WiFi, and Zigbee may coexist there and cause severe interference. In this paper, we propose a priority-based adaptive MAC (PA-MAC) protocol for WBANs in unlicensed bands, which allocates time slots dynamically, based on the traffic priority. Further, multiple channels are effectively utilized to reduce access delays in a WBAN, in the presence of coexisting systems. Our performance evaluation results show that the proposed PA-MAC outperforms the IEEE 802.15.4 MAC and the conventional priority-based MAC in terms of the average transmission time, throughput, energy consumption, and data collision ratio.

  20. Dynamic Channel Slot Allocation Scheme and Performance Analysis of Cyclic Quorum Multichannel MAC Protocol

    Directory of Open Access Journals (Sweden)

    Xing Hu

    2017-01-01

    Full Text Available In high diversity node situation, multichannel MAC protocol can improve the frequency efficiency, owing to fewer collisions compared with single-channel MAC protocol. And the performance of cyclic quorum-based multichannel (CQM MAC protocol is outstanding. Based on cyclic quorum system and channel slot allocation, it can avoid the bottleneck that others suffered from and can be easily realized with only one transceiver. To obtain the accurate performance of CQM MAC protocol, a Markov chain model, which combines the channel-hopping strategy of CQM protocol and IEEE 802.11 distributed coordination function (DCF, is proposed. The results of numerical analysis show that the optimal performance of CQM protocol can be obtained in saturation bound situation. And then we obtain the saturation bound of CQM system by bird swarm algorithm. In addition, to improve the performance of CQM protocol in unsaturation situation, a dynamic channel slot allocation of CQM (DCQM protocol is proposed, based on wavelet neural network. Finally, the performance of CQM protocol and DCQM protocol is simulated by Qualnet platform. And the simulation results show that the analytic and simulation results match very well; the DCQM performs better in unsaturation situation.

  1. A Cross-Layer Duty Cycle MAC Protocol Supporting a Pipeline Feature for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Young-Chon Kim

    2011-05-01

    Full Text Available Although the conventional duty cycle MAC protocols for Wireless Sensor Networks (WSNs such as RMAC perform well in terms of saving energy and reducing end-to-end delivery latency, they were designed independently and require an extra routing protocol in the network layer to provide path information for the MAC layer. In this paper, we propose a new cross-layer duty cycle MAC protocol with data forwarding supporting a pipeline feature (P-MAC for WSNs. P-MAC first divides the whole network into many grades around the sink. Each node identifies its grade according to its logical hop distance to the sink and simultaneously establishes a sleep/wakeup schedule using the grade information. Those nodes in the same grade keep the same schedule, which is staggered with the schedule of the nodes in the adjacent grade. Then a variation of the RTS/CTS handshake mechanism is used to forward data continuously in a pipeline fashion from the higher grade to the lower grade nodes and finally to the sink. No extra routing overhead is needed, thus increasing the network scalability while maintaining the superiority of duty-cycling. The simulation results in OPNET show that P-MAC has better performance than S-MAC and RMAC in terms of packet delivery latency and energy efficiency.

  2. McMAC: Towards a MAC Protocol with Multi-Constrained QoS Provisioning for Diverse Traffic in Wireless Body Area Networks

    OpenAIRE

    Monowar, Muhammad; Hassan, Mohammad; Bajaber, Fuad; Al-Hussein, Musaed; Alamri, Atif

    2012-01-01

    The emergence of heterogeneous applications with diverse requirements for resource-constrained Wireless Body Area Networks (WBANs) poses significant challenges for provisioning Quality of Service (QoS) with multi-constraints (delay and reliability) while preserving energy efficiency. To address such challenges, this paper proposes McMAC, a MAC protocol with multi-constrained QoS provisioning for diverse traffic classes in WBANs. McMAC classifies traffic based on their multi-constrained QoS de...

  3. Efficient MAC Protocol for Hybrid Wireless Network with Heterogeneous Sensor Nodes

    Directory of Open Access Journals (Sweden)

    Md. Nasre Alam

    2016-01-01

    Full Text Available Although several Directional Medium Access Control (DMAC protocols have been designed for use with homogeneous networks, it can take a substantial amount of time to change sensor nodes that are equipped with an omnidirectional antenna for sensor nodes with a directional antenna. Thus, we require a novel MAC protocol for use with an intermediate wireless network that consists of heterogeneous sensor nodes equipped with either an omnidirectional antenna or a directional antenna. The MAC protocols that have been designed for use in homogeneous networks are not suitable for use in a hybrid network due to deaf, hidden, and exposed nodes. Therefore, we propose a MAC protocol that exploits the characteristics of a directional antenna and can also work efficiently with omnidirectional nodes in a hybrid network. In order to address the deaf, hidden, and exposed node problems, we define RTS/CTS for the neighbor (RTSN/CTSN and Neighbor Information (NIP packets. The performance of the proposed MAC protocol is evaluated through a numerical analysis using a Markov model. In addition, the analytical results of the MAC protocol are verified through an OPNET simulation.

  4. A DUAL RESERVATION CDMA-BASED MAC PROTOCOL WITH POWER CONTROL FOR AD HOC NETWORKS

    Institute of Scientific and Technical Information of China (English)

    Jia Min; Chen Huimin; Yuan Yuhua

    2007-01-01

    This paper proposes a new multi-channel Medium Access Control (MAC) protocol named as Dual Reservation Code Division Multiple Access (CDMA) based MAC protocol with Power Control (DRCPC). The code channel is divided into common channel, broadcast channel and several data channels. And dynamic power control mechanism is implemented to reduce near-far interference. Compared with IEEE 802.11 Distributed Coordination Function (DCF) protocol, the results show that the proposed mechanism improves the average throughput and limits the transmission delay efficiently.

  5. Spectrum sharing in cognitive radio networks medium access control protocol based approach

    CERN Document Server

    Pandit, Shweta

    2017-01-01

    This book discusses the use of the spectrum sharing techniques in cognitive radio technology, in order to address the problem of spectrum scarcity for future wireless communications. The authors describe a cognitive radio medium access control (MAC) protocol, with which throughput maximization has been achieved. The discussion also includes use of this MAC protocol for imperfect sensing scenarios and its effect on the performance of cognitive radio systems. The authors also discuss how energy efficiency has been maximized in this system, by applying a simple algorithm for optimizing the transmit power of the cognitive user. The study about the channel fading in the cognitive user and licensed user and power adaption policy in this scenario under peak transmit power and interference power constraint is also present in this book.

  6. A Power-Optimized Cooperative MAC Protocol for Lifetime Extension in Wireless Sensor Networks.

    Science.gov (United States)

    Liu, Kai; Wu, Shan; Huang, Bo; Liu, Feng; Xu, Zhen

    2016-10-01

    In wireless sensor networks, in order to satisfy the requirement of long working time of energy-limited nodes, we need to design an energy-efficient and lifetime-extended medium access control (MAC) protocol. In this paper, a node cooperation mechanism that one or multiple nodes with higher channel gain and sufficient residual energy help a sender relay its data packets to its recipient is employed to achieve this objective. We first propose a transmission power optimization algorithm to prolong network lifetime by optimizing the transmission powers of the sender and its cooperative nodes to maximize their minimum residual energy after their data packet transmissions. Based on it, we propose a corresponding power-optimized cooperative MAC protocol. A cooperative node contention mechanism is designed to ensure that the sender can effectively select a group of cooperative nodes with the lowest energy consumption and the best channel quality for cooperative transmissions, thus further improving the energy efficiency. Simulation results show that compared to typical MAC protocol with direct transmissions and energy-efficient cooperative MAC protocol, the proposed cooperative MAC protocol can efficiently improve the energy efficiency and extend the network lifetime.

  7. Performance of MAC protocols in beaconing Mobile Adhoc Multibroadcast Networks

    OpenAIRE

    Rico García, Cristina; Lehner, Andreas; Robertson, Patrick; Strang, Thomas

    2010-01-01

    The investigation of infrastructureless safety applications in dierent transportation systems is a hot research topic. The nodes in thevnetwork are designed to advertise to the rest of the nodes informationabout the current traffic situation by means of short beacon messages containing speed, direction, positions and other relevant safety information. The scheduling should be organized by the MAC layer so that the transmitted messages arrive successfully as soon as possible at the recei...

  8. Persistent RCSMA: A MAC Protocol for a Distributed Cooperative ARQ Scheme in Wireless Networks

    Directory of Open Access Journals (Sweden)

    J. Alonso-Zárate

    2008-05-01

    Full Text Available The persistent relay carrier sensing multiple access (PRCSMA protocol is presented in this paper as a novel medium access control (MAC protocol that allows for the execution of a distributed cooperative automatic retransmission request (ARQ scheme in IEEE 802.11 wireless networks. The underlying idea of the PRCSMA protocol is to modify the basic rules of the IEEE 802.11 MAC protocol to execute a distributed cooperative ARQ scheme in wireless networks in order to enhance their performance and to extend coverage. A closed formulation of the distributed cooperative ARQ average packet transmission delay in a saturated network is derived in the paper. The analytical equations are then used to evaluate the performance of the protocol under different network configurations. Both the accuracy of the analysis and the performance evaluation of the protocol are supported and validated through computer simulations.

  9. MAC-layer protocol for TCP fairness in Wireless Mesh Networks

    KAUST Repository

    Nawab, Faisal

    2012-08-01

    In this paper we study the interactions of TCP and IEEE 802.11 MAC in Wireless Mesh Networks (WMNs). We use a Markov chain to capture the behavior of TCP sessions, particularly the impact on network throughput performance due to the effect of queue utilization and packet relaying. A closed form solution is derived to numerically determine the throughput. Based on the developed model, we propose a distributed MAC protocol to alleviate the unfairness problem in WMNs. Our protocol uses the age of packet as a priority metric for packet scheduling. Simulation is conducted to validate our model and to illustrate the fairness characteristics of our proposed MAC protocol. We conclude that we can achieve fairness with only little impact on network capacity.

  10. A network architecture for precision formation flying using the IEEE 802.11 MAC Protocol

    Science.gov (United States)

    Clare, Loren P.; Gao, Jay L.; Jennings, Esther H.; Okino, Clayton

    2005-01-01

    Precision Formation Flying missions involve the tracking and maintenance of spacecraft in a desired geometric formation. The strong coupling of spacecraft in formation flying control requires inter-spacecraft communication to exchange information. In this paper, we present a network architecture that supports PFF control, from the initial random deployment phase to the final formation. We show that a suitable MAC layer for the application protocol is IEEE's 802.11 MAC protocol. IEEE 802.11 MAC has two modes of operations: DCF and PCF. We show that DCF is suitable for the initial deployment phase while switching to PCF when the spacecraft are in formation improves jitter and throughput. We also consider the effect of routing on protocol performance and suggest when it is profitable to turn off route discovery to achieve better network performance.

  11. Multimode Communication Protocols Enabling Reconfigurable Radios

    Directory of Open Access Journals (Sweden)

    Berlemann Lars

    2005-01-01

    Full Text Available This paper focuses on the realization and application of a generic protocol stack for reconfigurable wireless communication systems. This focus extends the field of software-defined radios which usually concentrates on the physical layer. The generic protocol stack comprises common protocol functionality and behavior which are extended through specific parts of the targeted radio access technology. This paper considers parameterizable modules of basic protocol functions residing in the data link layer of the ISO/OSI model. System-specific functionality of the protocol software is realized through adequate parameterization and composition of the generic modules. The generic protocol stack allows an efficient realization of reconfigurable protocol software and enables a completely reconfigurable wireless communication system. It is a first step from side-by-side realized, preinstalled modes in a terminal towards a dynamic reconfigurable anymode terminal. The presented modules of the generic protocol stack can also be regarded as a toolbox for the accelerated and cost-efficient development of future communication protocols.

  12. Survey is based on Synchronized and Asynchronized Approach of MAC Protocols in WSN

    Directory of Open Access Journals (Sweden)

    Soni Chaurasia

    2010-07-01

    Full Text Available A wireless network is made of spatially distributed autonomous devices. These devices are called sensors. The sensor is used for monitoring physical or environmental conditions. The potential application of wireless sensor network is environmental monitoring, healthcare applications and tactical systems. In this paper focus is on the MAC protocol for WSN. Wireless sensor network is deployed for wide range to send and receive data with the help of medium. Here literature survey of MAC protocol based on the synchronized and asynchronized approach is described which is used to meet different objective like access a medium, statistical channel allocation, spectrum utilization

  13. Hopping control channel MAC protocol for opportunistic spectrum access networks

    Institute of Scientific and Technical Information of China (English)

    FU Jing-tuan; JI Hong; MAO Xu

    2010-01-01

    Opportunistic spectrum access (OSA) is considered as a promising approach to mitigate spectrum scarcity by allowing unlicensed users to exploit spectrum opportunities in licensed frequency bands. Derived from the existing channel-hopping multiple access (CHMA) protocol,we introduce a hopping control channel medium access control (MAC) protocol in the context of OSA networks. In our proposed protocol,all nodes in the network follow a common channel-hopping sequence; every frequency channel can be used as control channel and data channel. Considering primary users' occupancy of the channel,we use a primary user (PU) detection model to calculate the channel availability for unlicensed users' access. Then,a discrete Markov chain analytical model is applied to describe the channel states and deduce the system throughput. Through simulation,we present numerical results to demonstrate the throughput performance of our protocol and thus validate our work.

  14. Experimental Evaluation of Simulation Abstractions for Wireless Sensor Network MAC Protocols

    NARCIS (Netherlands)

    Halkes, G.P.; Langendoen, K.G.

    2010-01-01

    The evaluation ofMAC protocols forWireless Sensor Networks (WSNs) is often performed through simulation. These simulations necessarily abstract away from reality inmany ways. However, the impact of these abstractions on the results of the simulations has received only limited attention. Moreover,

  15. Detecting and Preventing Beacon Replay Attacks in Receiver-Initiated MAC Protocols for Energy Efficient WSNs

    DEFF Research Database (Denmark)

    Di Mauro, Alessio; Fafoutis, Xenofon; Mödersheim, Sebastian Alexander

    2013-01-01

    In receiver-initiated MAC protocols for Wireless Sensor Networks (WSNs), communication is initiated by the receiver of the data through beacons containing the receiver's identity. In this paper, we consider the case of a network intruder that captures and replays such beacons towards legitimate...

  16. An energy-efficient MAC protocol using dynamic queue management for delay-tolerant mobile sensor networks.

    Science.gov (United States)

    Li, Jie; Li, Qiyue; Qu, Yugui; Zhao, Baohua

    2011-01-01

    Conventional MAC protocols for wireless sensor network perform poorly when faced with a delay-tolerant mobile network environment. Characterized by a highly dynamic and sparse topology, poor network connectivity as well as data delay-tolerance, delay-tolerant mobile sensor networks exacerbate the severe power constraints and memory limitations of nodes. This paper proposes an energy-efficient MAC protocol using dynamic queue management (EQ-MAC) for power saving and data queue management. Via data transfers initiated by the target sink and the use of a dynamic queue management strategy based on priority, EQ-MAC effectively avoids untargeted transfers, increases the chance of successful data transmission, and makes useful data reach the target terminal in a timely manner. Experimental results show that EQ-MAC has high energy efficiency in comparison with a conventional MAC protocol. It also achieves a 46% decrease in packet drop probability, 79% increase in system throughput, and 25% decrease in mean packet delay.

  17. A hybrid path-oriented code assignment CDMA-based MAC protocol for underwater acoustic sensor networks.

    Science.gov (United States)

    Chen, Huifang; Fan, Guangyu; Xie, Lei; Cui, Jun-Hong

    2013-11-04

    Due to the characteristics of underwater acoustic channel, media access control (MAC) protocols designed for underwater acoustic sensor networks (UWASNs) are quite different from those for terrestrial wireless sensor networks. Moreover, in a sink-oriented network with event information generation in a sensor field and message forwarding to the sink hop-by-hop, the sensors near the sink have to transmit more packets than those far from the sink, and then a funneling effect occurs, which leads to packet congestion, collisions and losses, especially in UWASNs with long propagation delays. An improved CDMA-based MAC protocol, named path-oriented code assignment (POCA) CDMA MAC (POCA-CDMA-MAC), is proposed for UWASNs in this paper. In the proposed MAC protocol, both the round-robin method and CDMA technology are adopted to make the sink receive packets from multiple paths simultaneously. Since the number of paths for information gathering is much less than that of nodes, the length of the spreading code used in the POCA-CDMA-MAC protocol is shorter greatly than that used in the CDMA-based protocols with transmitter-oriented code assignment (TOCA) or receiver-oriented code assignment (ROCA). Simulation results show that the proposed POCA-CDMA-MAC protocol achieves a higher network throughput and a lower end-to-end delay compared to other CDMA-based MAC protocols.

  18. A Hybrid Path-Oriented Code Assignment CDMA-Based MAC Protocol for Underwater Acoustic Sensor Networks

    Directory of Open Access Journals (Sweden)

    Huifang Chen

    2013-11-01

    Full Text Available Due to the characteristics of underwater acoustic channel, media access control (MAC protocols designed for underwater acoustic sensor networks (UWASNs are quite different from those for terrestrial wireless sensor networks. Moreover, in a sink-oriented network with event information generation in a sensor field and message forwarding to the sink hop-by-hop, the sensors near the sink have to transmit more packets than those far from the sink, and then a funneling effect occurs, which leads to packet congestion, collisions and losses, especially in UWASNs with long propagation delays. An improved CDMA-based MAC protocol, named path-oriented code assignment (POCA CDMA MAC (POCA-CDMA-MAC, is proposed for UWASNs in this paper. In the proposed MAC protocol, both the round-robin method and CDMA technology are adopted to make the sink receive packets from multiple paths simultaneously. Since the number of paths for information gathering is much less than that of nodes, the length of the spreading code used in the POCA-CDMA-MAC protocol is shorter greatly than that used in the CDMA-based protocols with transmitter-oriented code assignment (TOCA or receiver-oriented code assignment (ROCA. Simulation results show that the proposed POCA-CDMA-MAC protocol achieves a higher network throughput and a lower end-to-end delay compared to other CDMA-based MAC protocols.

  19. An FEC Adaptive Multicast MAC Protocol for Providing Reliability in WLANs

    Science.gov (United States)

    Basalamah, Anas; Sato, Takuro

    For wireless multicast applications like multimedia conferencing, voice over IP and video/audio streaming, a reliable transmission of packets within short delivery delay is needed. Moreover, reliability is crucial to the performance of error intolerant applications like file transfer, distributed computing, chat and whiteboard sharing. Forward Error Correction (FEC) is frequently used in wireless multicast to enhance Packet Error Rate (PER) performance, but cannot assure full reliability unless coupled with Automatic Repeat Request forming what is knows as Hybrid-ARQ. While reliable FEC can be deployed at different levels of the protocol stack, it cannot be deployed on the MAC layer of the unreliable IEEE802.11 WLAN due to its inability to exchange ACKs with multiple recipients. In this paper, we propose a Multicast MAC protocol that enhances WLAN reliability by using Adaptive FEC and study it's performance through mathematical analysis and simulation. Our results show that our protocol can deliver high reliability and throughput performance.

  20. An Efficient and QoS Supported Multichannel MAC Protocol for Vehicular Ad Hoc Networks.

    Science.gov (United States)

    Song, Caixia; Tan, Guozhen; Yu, Chao

    2017-10-09

    Vehicular Ad Hoc Networks (VANETs) employ multichannel to provide a variety of safety and non-safety (transport efficiency and infotainment) applications, based on the IEEE 802.11p and IEEE 1609.4 protocols. Different types of applications require different levels Quality-of-Service (QoS) support. Recently, transport efficiency and infotainment applications (e.g., electronic map download and Internet access) have received more and more attention, and this kind of applications is expected to become a big market driver in a near future. In this paper, we propose an Efficient and QoS supported Multichannel Medium Access Control (EQM-MAC) protocol for VANETs in a highway environment. The EQM-MAC protocol utilizes the service channel resources for non-safety message transmissions during the whole synchronization interval, and it dynamically adjusts minimum contention window size for different non-safety services according to the traffic conditions. Theoretical model analysis and extensive simulation results show that the EQM-MAC protocol can support QoS services, while ensuring the high saturation throughput and low transmission delay for non-safety applications.

  1. An Efficient and QoS Supported Multichannel MAC Protocol for Vehicular Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Caixia Song

    2017-10-01

    Full Text Available Vehicular Ad Hoc Networks (VANETs employ multichannel to provide a variety of safety and non-safety (transport efficiency and infotainment applications, based on the IEEE 802.11p and IEEE 1609.4 protocols. Different types of applications require different levels Quality-of-Service (QoS support. Recently, transport efficiency and infotainment applications (e.g., electronic map download and Internet access have received more and more attention, and this kind of applications is expected to become a big market driver in a near future. In this paper, we propose an Efficient and QoS supported Multichannel Medium Access Control (EQM-MAC protocol for VANETs in a highway environment. The EQM-MAC protocol utilizes the service channel resources for non-safety message transmissions during the whole synchronization interval, and it dynamically adjusts minimum contention window size for different non-safety services according to the traffic conditions. Theoretical model analysis and extensive simulation results show that the EQM-MAC protocol can support QoS services, while ensuring the high saturation throughput and low transmission delay for non-safety applications.

  2. A Selective-Awakening MAC Protocol for Energy-Efficient Data Forwarding in Linear Sensor Networks

    Directory of Open Access Journals (Sweden)

    Iclia Villordo-Jimenez

    2018-01-01

    Full Text Available We introduce the Selective-Awakening MAC (SA-MAC protocol which is a synchronized duty-cycled protocol with pipelined scheduling for Linear Sensor Networks (LSNs. In the proposed protocol, nodes selectively awake depending on node density and traffic load conditions and on the state of the buffers of the receiving nodes. In order to characterize the performance of the proposed protocol, we present a Discrete-Time Markov Chain-based analysis that is validated through extensive discrete-event simulations. Our results show that SA-MAC significantly outperforms previous proposals in terms of energy consumption, throughput, and packet loss probability. This is particularly true under high node density and high traffic load conditions, which are expected to be common scenarios in the context of IoT applications. We also present an analysis by grade (i.e., the number of hops to the sink, which is located at one end of the LSN that reveals that LSNs exhibit heterogeneous performance depending on the nodes’ grade. Such results can be used as a design guideline for future LSN implementations.

  3. An Enhanced Reservation-Based MAC Protocol for IEEE 802.15.4 Networks

    Science.gov (United States)

    Afonso, José A.; Silva, Helder D.; Macedo, Pedro; Rocha, Luis A.

    2011-01-01

    The IEEE 802.15.4 Medium Access Control (MAC) protocol is an enabling standard for wireless sensor networks. In order to support applications requiring dedicated bandwidth or bounded delay, it provides a reservation-based scheme named Guaranteed Time Slot (GTS). However, the GTS scheme presents some drawbacks, such as inefficient bandwidth utilization and support to a maximum of only seven devices. This paper presents eLPRT (enhanced Low Power Real Time), a new reservation-based MAC protocol that introduces several performance enhancing features in comparison to the GTS scheme. This MAC protocol builds on top of LPRT (Low Power Real Time) and includes various mechanisms designed to increase data transmission reliability against channel errors, improve bandwidth utilization and increase the number of supported devices. A motion capture system based on inertial and magnetic sensors has been used to validate the protocol. The effectiveness of the performance enhancements introduced by each of the new features is demonstrated through the provision of both simulation and experimental results. PMID:22163826

  4. Enhancing MAC performance of DCF protocol for IEEE 802.11 wireless LANs

    Science.gov (United States)

    Choi, Woo-Yong

    2017-01-01

    The DCF (Distributed Coordination Function) is the basic MAC (Medium Access Control) protocol of IEEE 802.11 wireless LANs and compatible with various IEEE 802.11 PHY extensions. The performance of the DCF degrades exponentially as the number of nodes participating in the DCF transmission procedure increases. To deal with this problem, we propose a simple, however efficient modification of the DCF by which the performance of the DCF is greatly enhanced.

  5. IDMA-Based MAC Protocol for Satellite Networks with Consideration on Channel Quality

    Directory of Open Access Journals (Sweden)

    Gongliang Liu

    2014-01-01

    Full Text Available In order to overcome the shortcomings of existing medium access control (MAC protocols based on TDMA or CDMA in satellite networks, interleave division multiple access (IDMA technique is introduced into satellite communication networks. Therefore, a novel wide-band IDMA MAC protocol based on channel quality is proposed in this paper, consisting of a dynamic power allocation algorithm, a rate adaptation algorithm, and a call admission control (CAC scheme. Firstly, the power allocation algorithm combining the technique of IDMA SINR-evolution and channel quality prediction is developed to guarantee high power efficiency even in terrible channel conditions. Secondly, the effective rate adaptation algorithm, based on accurate channel information per timeslot and by the means of rate degradation, can be realized. What is more, based on channel quality prediction, the CAC scheme, combining the new power allocation algorithm, rate scheduling, and buffering strategies together, is proposed for the emerging IDMA systems, which can support a variety of traffic types, and offering quality of service (QoS requirements corresponding to different priority levels. Simulation results show that the new wide-band IDMA MAC protocol can make accurate estimation of available resource considering the effect of multiuser detection (MUD and QoS requirements of multimedia traffic, leading to low outage probability as well as high overall system throughput.

  6. Performance Analysis of a Cluster-Based MAC Protocol for Wireless Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Jesús Alonso-Zárate

    2010-01-01

    Full Text Available An analytical model to evaluate the non-saturated performance of the Distributed Queuing Medium Access Control Protocol for Ad Hoc Networks (DQMANs in single-hop networks is presented in this paper. DQMAN is comprised of a spontaneous, temporary, and dynamic clustering mechanism integrated with a near-optimum distributed queuing Medium Access Control (MAC protocol. Clustering is executed in a distributed manner using a mechanism inspired by the Distributed Coordination Function (DCF of the IEEE 802.11. Once a station seizes the channel, it becomes the temporary clusterhead of a spontaneous cluster and it coordinates the peer-to-peer communications between the clustermembers. Within each cluster, a near-optimum distributed queuing MAC protocol is executed. The theoretical performance analysis of DQMAN in single-hop networks under non-saturation conditions is presented in this paper. The approach integrates the analysis of the clustering mechanism into the MAC layer model. Up to the knowledge of the authors, this approach is novel in the literature. In addition, the performance of an ad hoc network using DQMAN is compared to that obtained when using the DCF of the IEEE 802.11, as a benchmark reference.

  7. Intelligent Local Avoided Collision (iLAC) MAC Protocol for Very High Speed Wireless Network

    Science.gov (United States)

    Hieu, Dinh Chi; Masuda, Akeo; Rabarijaona, Verotiana Hanitriniala; Shimamoto, Shigeru

    Future wireless communication systems aim at very high data rates. As the medium access control (MAC) protocol plays the central role in determining the overall performance of the wireless system, designing a suitable MAC protocol is critical to fully exploit the benefit of high speed transmission that the physical layer (PHY) offers. In the latest 802.11n standard [2], the problem of long overhead has been addressed adequately but the issue of excessive colliding transmissions, especially in congested situation, remains untouched. The procedure of setting the backoff value is the heart of the 802.11 distributed coordination function (DCF) to avoid collision in which each station makes its own decision on how to avoid collision in the next transmission. However, collision avoidance is a problem that can not be solved by a single station. In this paper, we introduce a new MAC protocol called Intelligent Local Avoided Collision (iLAC) that redefines individual rationality in choosing the backoff counter value to avoid a colliding transmission. The distinguishing feature of iLAC is that it fundamentally changes this decision making process from collision avoidance to collaborative collision prevention. As a result, stations can avoid colliding transmissions with much greater precision. Analytical solution confirms the validity of this proposal and simulation results show that the proposed algorithm outperforms the conventional algorithms by a large margin.

  8. 1950s Athens as Palimpsest: A BBC Radio Play by Louis MacNeice

    Directory of Open Access Journals (Sweden)

    Konstantina Georganta

    2015-11-01

    Full Text Available Louis MacNeice’s Portrait of Athens, a radio play broadcast by the BBC in November 1951, came at a time of reconstruction throughout Europe but also at a time when the world was on the verge of yet another war. In it we find the city’s bones, Athens of Thucydides, Demosthenes, Pericles and Socrates, but also a modern city where you could hear street cries, radio tunes and trams and visit both Kolonaki and the district of New Smyrna where Asia Minor refugees had settled almost thirty years earlier. Twenty-four centuries were transposed to twenty-four hours and twenty-four hours squeezed into the space of one with the play focusing on questions of memory, identity, and lived or remembered traumas. What the audience got as a result was a representation of the varied layers that made up modern Athens, a portrait of the city as palimpsest in contrast to other accounts of the same period where the past dominated over the present making the latter non visible.

  9. Radio protocols for LTE and LTE-advanced

    CERN Document Server

    Yi, SeungJune; Lee, YoungDae; Park, SungJun; Jung, SungHoon

    2012-01-01

    Provides a unique focus on radio protocols for LTE and LTE-Advanced (LTE-A) Giving readers a valuable understanding of LTE radio protocols, this book covers LTE (Long-Term Evolution) Layer 2/3 radio protocols as well as new features including LTE-Advanced. It is divided into two sections to differentiate between the two technologies' characteristics. The authors systematically explain the design principles and functions of LTE radio protocols during the development of mobile handsets. The book also provides essential knowledge on the interaction between mobile networks a

  10. An Empirical Study and some Improvements of the MiniMac Protocol for Secure Computation

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Lauritsen, Rasmus; Toft, Tomas

    2014-01-01

    Recent developments in Multi-party Computation (MPC) has resulted in very efficient protocols for dishonest majority in the preprocessing model. In particular, two very promising protocols for Boolean circuits have been proposed by Nielsen et al. (nicknamed TinyOT) and by Damg˚ard and Zakarias...... suggest a modification of MiniMac that achieves increased parallelism at no extra communication cost. This gives an asymptotic improvement of the original protocol as well as an 8-fold speed-up of our implementation. We compare the resulting protocol to TinyOT for the case of secure computation in parallel...... of a large number of AES encryptions and find that it performs better than results reported so far on TinyOT, on the same hardware.p...

  11. Cross Layer PHY-MAC Protocol for Wireless Static and Mobile Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Chris Blondia

    2008-11-01

    Full Text Available Multihop mobile wireless networks have drawn a lot of attention in recent years thanks to their wide applicability in civil and military environments. Since the existing IEEE 802.11 distributed coordination function (DCF standard does not provide satisfactory access to the wireless medium in multihop mobile networks, we have designed a cross-layer protocol, (CroSs-layer noise aware power driven MAC (SNAPdMac, which consists of two parts. The protocol first concentrates on the flexible adjustment of the upper and lower bounds of the contention window (CW to lower the number of collisions. In addition, it uses a power control scheme, triggered by the medium access control (MAC layer, to limit the waste of energy and also to decrease the number of collisions. Thanks to a noticeable energy conservation and decrease of the number of collisions, it prolongs significantly the lifetime of the network and delays the death of the first node while increasing both the throughput performance and the sending bit rate/throughput fairness among contending flows.

  12. Adaptive MAC-layer protocol for multiservice digital access via tree and branch communication networks

    Science.gov (United States)

    Sriram, Kotikalapudi; Li, Chia-Chang; Magill, Peter; Whitaker, Norman A.; Dail, James E.; Dajer, Miguel A.; Siller, Curtis A.

    1995-11-01

    Described here is an adaptive MAC-layer protocol that supports multiservice (STM and ATM) applications in the context of subscriber access to tree and branch (e.g., fiber-coaxial cable) networks. The protocol adapts to changing demands for a mix of circuit and cell mode applications, and efficiently allocates upstream and downstream bandwidth to a variety of bursty and isochronous traffic sources. In the case of a hybrid fiber-coaxial (HFC) network the protocol resides in customer premises equipment and a common head-end controller. A medium-access control (MAC) processor provides for dividing the time domain for a given digital bitstream into successive frames, each with multiple STM and ATM time slots. Within the STM region of a frame, variable length time slots are allocated to calls (e.g., telephony, video telephony) requiring different amounts of bandwidth. A contention access signaling channel is also provided in this region for call control and set-up requests. Within the ATM region fixed-length time slots accommodate one individual ATM cell. These ATM time slots may be reserved for a user for the duration of a call or burst of successive ATM cells, or shared via a contention process. At least one contention time slot is available for signaling messages related to ATM call control and set-up requests. Further, the fixed-length ATM time slots may be reserved by a user for the duration of a call, or shared through a contention process. This paper describes the MAC-layer protocol, its relation to circuit- and ATM- amenable applications, and its performance with respect to signaling throughput and latency, and bandwidth efficiency for several service scenarios.

  13. McMAC: towards a MAC protocol with multi-constrained QoS provisioning for diverse traffic in Wireless Body Area Networks.

    Science.gov (United States)

    Monowar, Muhammad Mostafa; Hassan, Mohammad Mehedi; Bajaber, Fuad; Al-Hussein, Musaed; Alamri, Atif

    2012-11-12

    The emergence of heterogeneous applications with diverse requirements for resource-constrained Wireless Body Area Networks (WBANs) poses significant challenges for provisioning Quality of Service (QoS) with multi-constraints (delay and reliability) while preserving energy efficiency. To address such challenges, this paper proposes McMAC,a MAC protocol with multi-constrained QoS provisioning for diverse traffic classes in WBANs. McMAC classifies traffic based on their multi-constrained QoS demands and introduces a novel superframe structure based on the "transmit-whenever-appropriate"principle, which allows diverse periods for diverse traffic classes according to their respective QoS requirements. Furthermore, a novel emergency packet handling mechanism is proposedto ensure packet delivery with the least possible delay and the highest reliability. McMAC is also modeled analytically, and extensive simulations were performed to evaluate its performance. The results reveal that McMAC achieves the desired delay and reliability guarantee according to the requirements of a particular traffic class while achieving energy efficiency.

  14. A Priority-aware Frequency Domain Polling MAC Protocol for OFDMA-based Networks in Cyber-physical Systems

    Institute of Scientific and Technical Information of China (English)

    Meng Zheng; Junru Lin; Wei Liang; Haibin Yu

    2015-01-01

    Wireless networking in cyber-physical systems(CPSs) is characteristically different from traditional wireless systems due to the harsh radio frequency environment and applications that impose high real-time and reliability constraints.One of the fundamental considerations for enabling CPS networks is the medium access control protocol. To this end, this paper proposes a novel priority-aware frequency domain polling medium access control(MAC) protocol, which takes advantage of an orthogonal frequency-division multiple access(OFDMA)physical layer to achieve instantaneous priority-aware polling.Based on the polling result, the proposed work then optimizes the resource allocation of the OFDMA network to further improve the data reliability. Due to the non-polynomial-complete nature of the OFDMA resource allocation, we propose two heuristic rules,based on which an efficient solution algorithm to the OFDMA resource allocation problem is designed. Simulation results show that the reliability performance of CPS networks is significantly improved because of this work.

  15. Performance analysis for a QoS-aware hybrid token-CDMA MAC protocol

    CSIR Research Space (South Africa)

    Liu, YS

    2007-09-01

    Full Text Available ) 20000 Bad state duration ( i badτ ) 3.2 ms Bad state ibadPEP 1.0 Good state igoodPEP Holtzman’s approximation WTRP Channel bit rate 1.28 Mbps Signal to Noise Rato (SNR) 8 dB .... INTRODUCTION d hoc and wireless mesh networks (WMNs) [1] are commonly known to implement IEEE 802.11 related schemes as their medium access control (MAC) protocols. It is known from [2,3] that with the 802.11 based scheme; the performance is degraded...

  16. A feedback-retransmission based asynchronous frequency hopping MAC protocol for military aeronautical ad hoc networks

    Directory of Open Access Journals (Sweden)

    Jinhui TANG

    2018-05-01

    Full Text Available Attacking time-sensitive targets has rigid demands for the timeliness and reliability of information transmission, while typical Media Access Control (MAC designed for this application works well only in very light-load scenarios; as a consequence, the performances of system throughput and channel utilization are degraded. For this problem, a feedback-retransmission based asynchronous FRequency hopping Media Access (FRMA control protocol is proposed. Burst communication, asynchronous Frequency Hopping (FH, channel coding, and feedback retransmission are utilized in FRMA. With the mechanism of asynchronous FH, immediate packet transmission and multi-packet reception can be realized, and thus the timeliness is improved. Furthermore, reliability can be achieved via channel coding and feedback retransmission. With theories of queuing theory, Markov model, packets collision model, and discrete Laplace transformation, the formulas of packet success probability, system throughput, average packet end-to-end delay, and delay distribution are obtained. The approximation accuracy of theoretical derivation is verified by experimental results. Within a light-load network, the proposed FRMA has the ability of millisecond delay and 99% reliability as well as outperforms the non-feedback-retransmission based asynchronous frequency hopping media access control protocol. Keywords: Ad hoc networks, Aeronautical communications, Frequency hopping, Media Access Control (MAC, Time-sensitive

  17. Low Duty-Cycling MAC Protocol for Low Data-Rate Medical Wireless Body Area Networks

    Directory of Open Access Journals (Sweden)

    Chongqing Zhang

    2017-05-01

    Full Text Available Wireless body area networks (WBANs are severely energy constrained, and how to improve the energy efficiency so as to prolong the network lifetime as long as possible is one of the most important goals of WBAN research. Low data-rate WBANs are promising to cut down the energy consumption and extend the network lifetime. Considering the characteristics and demands of low data-rate WBANs, a low duty-cycling medium access control (MAC protocol is specially designed for this kind of WBAN in this paper. Longer superframes are exploited to cut down the energy consumed on the transmissions and receptions of redundant beacon frames. Insertion time slots are embedded into the inactive part of a superframe to deliver the frames and satisfy the quality of service (QoS requirements. The number of the data subsections in an insertion time slot can be adaptively adjusted so as to accommodate low data-rate WBANs with different traffic. Simulation results show that the proposed MAC protocol performs well under the condition of low data-rate monitoring traffic.

  18. Performance Analysis of Modified Accelerative Preallocation MAC Protocol for Passive Star-Coupled WDMA Networks

    Science.gov (United States)

    Yun, Changho; Kim, Kiseon

    2006-04-01

    For the passive star-coupled wavelength-division multiple-access (WDMA) network, a modified accelerative preallocation WDMA (MAP-WDMA) media access control (MAC) protocol is proposed, which is based on AP-WDMA. To show the advantages of MAP-WDMA as an adequate MAC protocol for the network over AP-WDMA, the channel utilization, the channel-access delay, and the latency of MAP-WDMA are investigated and compared with those of AP-WDMA under various data traffic patterns, including uniform, quasi-uniform type, disconnected type, mesh type, and ring type data traffics, as well as the assumption that a given number of network stations is equal to that of channels, in other words, without channel sharing. As a result, the channel utilization of MAP-WDMA can be competitive with respect to that of AP-WDMA at the expense of insignificantly higher latency. Namely, if the number of network stations is small, MAP-WDMA provides better channel utilization for uniform, quasi-uniform-type, and disconnected-type data traffics at all data traffic loads, as well as for mesh and ring-type data traffics at low data traffic loads. Otherwise, MAP-WDMA only outperforms AP-WDMA for the first three data traffics at higher data traffic loads. In the aspect of channel-access delay, MAP-WDMA gives better performance than AP-WDMA, regardless of data traffic patterns and the number of network stations.

  19. An Energy-Efficient MAC Protocol Using Dynamic Queue Management for Delay-Tolerant Mobile Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yugui Qu

    2011-02-01

    Full Text Available Conventional MAC protocols for wireless sensor network perform poorly when faced with a delay-tolerant mobile network environment. Characterized by a highly dynamic and sparse topology, poor network connectivity as well as data delay-tolerance, delay-tolerant mobile sensor networks exacerbate the severe power constraints and memory limitations of nodes. This paper proposes an energy-efficient MAC protocol using dynamic queue management (EQ-MAC for power saving and data queue management. Via data transfers initiated by the target sink and the use of a dynamic queue management strategy based on priority, EQ-MAC effectively avoids untargeted transfers, increases the chance of successful data transmission, and makes useful data reach the target terminal in a timely manner. Experimental results show that EQ-MAC has high energy efficiency in comparison with a conventional MAC protocol. It also achieves a 46% decrease in packet drop probability, 79% increase in system throughput, and 25% decrease in mean packet delay.

  20. McMAC: Towards a MAC Protocol with Multi-Constrained QoS Provisioning for Diverse Traffic in Wireless Body Area Networks

    Directory of Open Access Journals (Sweden)

    Muhammad Mostafa Monowar

    2012-11-01

    Full Text Available The emergence of heterogeneous applications with diverse requirements forresource-constrained Wireless Body Area Networks (WBANs poses significant challengesfor provisioning Quality of Service (QoS with multi-constraints (delay and reliability whilepreserving energy efficiency. To address such challenges, this paper proposes McMAC,a MAC protocol with multi-constrained QoS provisioning for diverse traffic classes inWBANs. McMAC classifies traffic based on their multi-constrained QoS demands andintroduces a novel superframe structure based on the "transmit-whenever-appropriate"principle, which allows diverse periods for diverse traffic classes according to their respectiveQoS requirements. Furthermore, a novel emergency packet handling mechanism is proposedto ensure packet delivery with the least possible delay and the highest reliability. McMACis also modeled analytically, and extensive simulations were performed to evaluate itsperformance. The results reveal that McMAC achieves the desired delay and reliabilityguarantee according to the requirements of a particular traffic class while achieving energyefficiency.

  1. Link-layer Jamming Attacks on S-MAC

    NARCIS (Netherlands)

    Law, Y.W.; Hartel, Pieter H.; den Hartog, Jeremy; Havinga, Paul J.M.

    2004-01-01

    We argue that among denial-of-service (DoS) attacks, link-layer jamming is a more attractive option to attackers than radio jamming is. By exploiting the semantics of the link-layer protocol (aka MAC protocol), an attacker can achieve better efficiency than blindly jamming the radio signals alone.

  2. Link-layer jamming attacks on S-MAC

    NARCIS (Netherlands)

    Law, Y.W.; Hartel, Pieter H.; den Hartog, Jeremy; Havinga, Paul J.M.

    We argue that among denial-of-service (DoS) attacks, link-layer jamming is a more attractive option to attackers than radio jamming is. By exploiting the semantics of the link-layer protocol (aka MAC protocol), an attacker can achieve better efficiency than blindly jamming the radio signals alone.

  3. Low Latency MAC Protocol in Wireless Sensor Networks Using Timing Offset

    Science.gov (United States)

    Choi, Seung Sik

    This paper proposes a low latency MAC protocol that can be used in sensor networks. To extend the lifetime of sensor nodes, the conventional solution is to synchronize active/sleep periods of all sensor nodes. However, due to these synchronized sensor nodes, packets in the intermediate nodes must wait until the next node wakes up before it can forward a packet. This induces a large delay in sensor nodes. To solve this latency problem, a clustered sensor network which uses two types of sensor nodes and layered architecture is considered. Clustered heads in each cluster are synchronized with different timing offsets to reduce the sleep delay. Using this concept, the latency problem can be solved and more efficient power usage can be obtained.

  4. Fast Oblivious AES A Dedicated application of the MiniMac protocol

    DEFF Research Database (Denmark)

    Zakarias, Rasmus Winther; Damgård, Ivan Bjerre

    2015-01-01

    We present an actively secure multi-partycomputation of the Advanced Encryption Standard (AES). To the best of our knowledge it is the fastest of its kind to date. We start from an efficient actively secure evaluation of general binary circuits that was implemented by the authors of [DLT14......]. They presented an optimized implementation of the so-called MiniMac protocol [DZ13] that runs in the pre-processing model, and applied this to a binary AES circuit. In this paper we de- scribe how to dedicate the pre-processing to the structure of AES, which improves significantly the throughput and latency...... of previous actively secure implementations. We get a latency of about 6 ms and amortised time about 0.4 ms per AES block, which seems completely adequate for practical applications such as verification of 1-time passwords....

  5. Altruistic Backoff: Collision Avoidance for Receiver-Initiated MAC Protocols for Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Fafoutis, Xenofon; Orfanidis, Charalampos; Dragoni, Nicola

    2014-01-01

    In receiver-initiated medium access control (MAC) protocols for wireless sensor networks, communication is initiated by the receiver node which transmits beacons indicating its availability to receive data. In the case of multiple senders having traffic for a given receiver, such beacons form...... points where collisions are likely to happen. In this paper, we present altruistic backoff (AB), a novel collision avoidance mechanism that aims to avoid collisions before the transmission of a beacon. As a result of an early backoff, senders spend less time in idle listening waiting for a beacon, thus...... saving significant amounts of energy. We present an implementation of AB for Texas Instruments' eZ430-rf2500 sensor nodes and we evaluate its performance with simulations and experiments....

  6. A hybrid MAC protocol design for energy-efficient very-high-throughput millimeter wave, wireless sensor communication networks

    Science.gov (United States)

    Jian, Wei; Estevez, Claudio; Chowdhury, Arshad; Jia, Zhensheng; Wang, Jianxin; Yu, Jianguo; Chang, Gee-Kung

    2010-12-01

    This paper presents an energy-efficient Medium Access Control (MAC) protocol for very-high-throughput millimeter-wave (mm-wave) wireless sensor communication networks (VHT-MSCNs) based on hybrid multiple access techniques of frequency division multiplexing access (FDMA) and time division multiplexing access (TDMA). An energy-efficient Superframe for wireless sensor communication network employing directional mm-wave wireless access technologies is proposed for systems that require very high throughput, such as high definition video signals, for sensing, processing, transmitting, and actuating functions. Energy consumption modeling for each network element and comparisons among various multi-access technologies in term of power and MAC layer operations are investigated for evaluating the energy-efficient improvement of proposed MAC protocol.

  7. A new energy-efficient MAC protocol with noise-based transmitted-reference modulation for wireless sensor network

    NARCIS (Netherlands)

    Morshed, S.; Heijenk, Geert; Meijerink, Arjan; Ye, D.; van der Zee, Ronan A.R.; Bentum, Marinus Jan

    2013-01-01

    Energy-constrained behavior of sensor nodes is one of the most important criteria for successful deployment of wireless sensor networks. The medium access control (MAC) protocol determines to a large extent the time a sensor node transceiver spends listening or transmitting, and hence the energy

  8. Base station MAC with APRMA protocol for broadband multimedia ATM in micro/pico-cellular mobile networks

    DEFF Research Database (Denmark)

    Le, Khanh Hoang; Nielsen, Søren Nørskov; Dittmann, Lars

    1998-01-01

    The concept for a wireless ATM access system that enables seamless mobile connectivity to the B-ISDN is presented. It is based on small, low cost and intelligent base stations running a medium access control (MAC) protocol using adaptive packet reservation multiple access (APRMA). Both...

  9. Alert: An Adaptive Low-Latency Event-Driven MAC Protocol for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Vinod Namboodiri

    2011-01-01

    Full Text Available Collection of rare but delay-critical messages from a group of sensor nodes is a key process in many wireless sensor network applications. This is particularly important for security-related applications like intrusion detection and fire alarm systems. An event sensed by multiple sensor nodes in the network can trigger many messages to be sent simultaneously. We present Alert, a MAC protocol for collecting event-triggered urgent messages from a group of sensor nodes with minimum latency and without requiring any cooperation or prescheduling among the senders or between senders and receiver during protocol execution. Alert is designed to handle multiple simultaneous messages from different nodes efficiently and reliably, minimizing the overall delay to collect all messages along with the delay to get the first message. Moreover, the ability of the network to handle a large number of simultaneous messages does not come at the cost of excessive delays when only a few messages need to be handled. We analyze Alert and evaluate its feasibility and performance with an implementation on commodity hardware. We further compare Alert with existing approaches through simulations and show the performance improvement possible through Alert.

  10. Latency-Optimized and Energy-Efficient MAC Protocol for Underwater Acoustic Sensor Networks: A Cross-Layer Approach

    Directory of Open Access Journals (Sweden)

    Cheng Xiuzhen

    2010-01-01

    Full Text Available Considering the energy constraint for fixed sensor nodes and the unacceptable long propagation delay, especially for latency sensitive applications of underwater acoustic sensor networks, we propose a MAC protocol that is latency-optimized and energy-efficient scheme and combines the physical layer and the MAC layer to shorten transmission delay. On physical layer, we apply convolution coding and interleaver for transmitted information. Moreover, dynamic code rate is exploited at the receiver side to accelerate data reception rate. On MAC layer, unfixed frame length scheme is applied to reduce transmission delay, and to ensure the data successful transmission rate at the same time. Furthermore, we propose a network topology: an underwater acoustic sensor network with mobile agent. Through fully utilizing the supper capabilities on computation and mobility of autonomous underwater vehicles, the energy consumption for fixed sensor nodes can be extremely reduced, so that the lifetime of networks is extended.

  11. 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.

  12. QoS Support Polling Scheme for Multimedia Traffic in Wireless LAN MAC Protocol

    Institute of Scientific and Technical Information of China (English)

    YANG Zhijun; ZHAO Dongfeng

    2008-01-01

    Quality of service (QoS) support is a key attribute for multimedia traffic including video, voice, and data in wireless local area networks (LANs) but is limited in 802.11-based wireless LANs. A polling-based scheme called the point coordination function (PCF) was developed for 802.11 LANs to support the trans-mission of multimedia traffic. However, the PCF is not able to meet the desired practical traffic differentiation requirements for real-time data. This paper describes a QoS support polling scheme based on the IEEE 802.11 medium access control (MAC) protocol. The scheme uses a two-level polling mechanism with the QoS classes differentiated by two different access policies. Stations with higher priority traffic such as key or real-time data form the first level and can access the common channel through an exhaustive access policy. Other stations with lower priority traffic form the second level and can access the channel through a gated access policy. A system model based on imbedded Markov chain theory and a generation function were setup to explicitly analyze the mean information packet waiting time of the two-level polling scheme. Theo-retical and simulation results show that the new scheme efficiently differentiates services to guarantee better QoS and system stability.

  13. The Impact of Dynamic RTS Threshold Adjustment for IEEE 802.11 MAC Protocol

    Directory of Open Access Journals (Sweden)

    Mostafa Mjidi

    2009-01-01

    Full Text Available In recent years, wireless technologies and application received great attention. The Medium Access Control (MAC protocol is the main element that determines the efficiency in sharing the limited communication bandwidth of the wireless channel in wireless local area networks (WLANs. IEEE 802.11 introduced the optional RTS/CTS handshaking mechanism to address the hidden terminal problem as well as to reduces the chance of collision in case of higher node density and traffic. RTS Threshold (RT determines when RTS/CTS mechanism should be used and proved to be an important parameter for performance characteristics in data transmission. We first investigate to find a meaningful threshold value according to the network situation and determine the impact of using or disengaging the RTS/CTS optional mechanism and dynamically adjust the RTS Threshold to maximize data transmission. The results show a significant improvement over existing CSMA/CA and RTS/CTS schemes. Our adaptive scheme performed even better when data rate increases. We verify our proposed scheme both analytically and with extensive network simulation using ns-2.

  14. Asymmetric Propagation Delay-Aware TDMA MAC Protocol for Mobile Underwater Acoustic Sensor Networks

    Directory of Open Access Journals (Sweden)

    A-Ra Cho

    2018-06-01

    Full Text Available The propagation delay in mobile underwater acoustic sensor network (MUASN is asymmetric because of its low sound propagation speed, and this asymmetry grows with the increase in packet travel time, which damages the collision avoidance mechanism of the spatial reuse medium access control (MAC protocols for MUASN. We propose an asymmetric propagation delay-aware time division multiple access (APD-TDMA for a MUASN in which periodic data packet transmission is required for a sink node (SN. Collisions at the SN are avoided by deferring data packet transmission after reception of a beacon packet from the SN, and data packets are arrived at the SN in a packet-train manner. The time-offset, which is the time for a node to wait before the transmission of a data packet after reception of a beacon packet, is determined by estimating the propagation delay over two consecutive cycles such that the idle interval at the SN is minimized, and this time-offset is announced by the beacon packet. Simulation results demonstrate that the APD-TDMA improves the channel access delay and the channel utilization by approximately 20% and 30%, respectively, compared with those of the block time bounded TDMA under the given network conditions.

  15. ATCA observations of the MACS-Planck Radio Halo Cluster Project. II. Radio observations of an intermediate redshift cluster sample

    Science.gov (United States)

    Martinez Aviles, G.; Johnston-Hollitt, M.; Ferrari, C.; Venturi, T.; Democles, J.; Dallacasa, D.; Cassano, R.; Brunetti, G.; Giacintucci, S.; Pratt, G. W.; Arnaud, M.; Aghanim, N.; Brown, S.; Douspis, M.; Hurier, J.; Intema, H. T.; Langer, M.; Macario, G.; Pointecouteau, E.

    2018-04-01

    Aim. A fraction of galaxy clusters host diffuse radio sources whose origins are investigated through multi-wavelength studies of cluster samples. We investigate the presence of diffuse radio emission in a sample of seven galaxy clusters in the largely unexplored intermediate redshift range (0.3 http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A94

  16. The Control Packet Collision Avoidance Algorithm for the Underwater Multichannel MAC Protocols via Time-Frequency Masking

    Directory of Open Access Journals (Sweden)

    Yang Yu

    2016-01-01

    Full Text Available Establishing high-speed and reliable underwater acoustic networks among multiunmanned underwater vehicles (UUVs is basic to realize cooperative and intelligent control among different UUVs. Nevertheless, different from terrestrial network, the propagation speed of the underwater acoustic network is 1500 m/s, which makes the design of the underwater acoustic network MAC protocols a big challenge. In accordance with multichannel MAC protocols, data packets and control packets are transferred through different channels, which lowers the adverse effect of acoustic network and gradually becomes the popular issues of underwater acoustic networks MAC protocol research. In this paper, we proposed a control packet collision avoidance algorithm utilizing time-frequency masking to deal with the control packets collision in the control channel. This algorithm is based on the scarcity of the noncoherent underwater acoustic communication signals, which regards collision avoiding as separation of the mixtures of communication signals from different nodes. We first measure the W-Disjoint Orthogonality of the MFSK signals and the simulation result demonstrates that there exists time-frequency mask which can separate the source signals from the mixture of the communication signals. Then we present a pairwise hydrophones separation system based on deep networks and the location information of the nodes. Consequently, the time-frequency mask can be estimated.

  17. [Study protocol of a prevention of recurrent suicidal behaviour program based on case management (PSyMAC)].

    Science.gov (United States)

    Sáiz, Pilar A; Rodríguez-Revuelta, Julia; González-Blanco, Leticia; Burón, Patricia; Al-Halabí, Susana; Garrido, Marlen; García-Alvarez, Leticia; García-Portilla, Paz; Bobes, Julio

    2014-01-01

    Prevention of suicidal behaviour is a public health priority in the European Union. A previous suicide attempt is the best risk predictor for future attempts, as well as completed suicides. The primary aim of this article is to describe a controlled study protocol designed for prevention of recurrent suicidal behaviour that proposes case management, and includes a psychoeducation program, as compared with the standard intervention (PSyMAC). Patients admitted from January 2011 to June 2013 to the emergency room of the Hospital Universitario Central de Asturias were evaluated using a protocol including sociodemographic, psychiatric, and psychosocial assessment. Patients were randomly assigned to either a group receiving continuous case management including participation in a psychoeducation program (experimental group), or a control group receiving standard care. The primary objective is to examine whether or not the period of time until recurrent suicidal behaviour in the experimental group is significantly different from that of the control group. PSyMAC proposes low cost and easily adaptable interventions to the usual clinical setting that can help to compensate the shortcoming of specific action protocols and suicidal behaviour prevention programs in our country. The evaluation of PSyMAC results will determine their real effectivity as a case-magament program to reduce suicidal risk. Copyright © 2013 SEP y SEPB. Published by Elsevier España. All rights reserved.

  18. Localized radio frequency communication using asynchronous transfer mode protocol

    Science.gov (United States)

    Witzke, Edward L.; Robertson, Perry J.; Pierson, Lyndon G.

    2007-08-14

    A localized wireless communication system for communication between a plurality of circuit boards, and between electronic components on the circuit boards. Transceivers are located on each circuit board and electronic component. The transceivers communicate with one another over spread spectrum radio frequencies. An asynchronous transfer mode protocol controls communication flow with asynchronous transfer mode switches located on the circuit boards.

  19. A New MAC Protocol with Pseudo-TDMA Behavior for Supporting Quality of Service in 802.11 Wireless LANs

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available A new medium access control (MAC protocol is proposed for quality-of-service (QoS support in wireless local area networks (WLAN. The protocol is an alternative to the recent enhancement 802.11e. A new priority policy provides the system with better performance by simulating time division multiple access (TDMA functionality. Collisions are reduced and starvation of low-priority classes is prevented by a distributed admission control algorithm. The model performance is found analytically extending previous work on this matter. The results show that a better organization of resources is achieved through this scheme. Throughput analysis is verified with OPNET simulations.

  20. DESIGN OF CAUCUS MEDIUM ACCESS CONTROL (C-MAC PROTOCOL FOR WIRELESS SENSOR NETWORKS IN SMART GRIDS

    Directory of Open Access Journals (Sweden)

    JEETU SHARMA

    2017-10-01

    Full Text Available A Caucus-based medium access control protocol (C-MAC is proposed to reduce the end to end delay and battery consumption of the sensor nodes deployed in the monitoring of various smart grid regions, such as substation, pole and wires, perimeter security, real time and non-real-time monitoring using wireless sensor networks. The objective is to prolong the network lifetime and to reduce the end to end delay by mitigating the energy-hole problem and by eliminating bottlenecks significantly by using caucus based efficient synchronization techniques in multi-hop square grid topology of the wireless sensor networks (WSNs. The protocol self-reliantly and adaptively schedules node’s wake-up times, decreases idle listening and collisions, increases network throughput, and extends network lifetime. It induces a low duty cycle for adjusting wake-up times of sensor nodes. The appropriate selection of active and sleep time slots and next hop relay nodes are proposed to minimize the data transmission latency and to reduce battery consumption to increase the network lifetime. The uniform and synchronized transmission of the data packets is of prime importance to improve the network performance. Simulation results justify that the proposed C-MAC protocol increases the network lifetime, successful data transmission ratio along-with the reduction in end to end delay. The objective of this paper is to envisage benefits and utilization of C-MAC protocol for WSNs deployed in smart grids and to draw the attention of researchers in this area.

  1. Search for low-frequency diffuse radio emission around a shock in the massive galaxy cluster MACS J0744.9+3927

    Science.gov (United States)

    Wilber, A.; Brüggen, M.; Bonafede, A.; Rafferty, D.; Savini, F.; Shimwell, T.; van Weeren, R. J.; Botteon, A.; Cassano, R.; Brunetti, G.; De Gasperin, F.; Wittor, D.; Hoeft, M.; Birzan, L.

    2018-05-01

    Merging galaxy clusters produce low-Mach-number shocks in the intracluster medium. These shocks can accelerate electrons to relativistic energies that are detectable at radio frequencies. MACS J0744.9+3927 is a massive [M500 = (11.8 ± 2.8) × 1014 M⊙], high-redshift (z = 0.6976) cluster where a Bullet-type merger is presumed to have taken place. Sunyaev-Zel'dovich maps from MUSTANG indicate that a shock, with Mach number M = 1.0-2.9 and an extension of ˜200 kpc, sits near the centre of the cluster. The shock is also detected as a brightness and temperature discontinuity in X-ray observations. To search for diffuse radio emission associated with the merger, we have imaged the cluster with the LOw Frequency ARray (LOFAR) at 120-165 MHz. Our LOFAR radio images reveal previously undetected AGN emission, but do not show clear cluster-scale diffuse emission in the form of a radio relic nor a radio halo. The region of the shock is on the western edge of AGN lobe emission from the brightest cluster galaxy. Correlating the flux of known shock-induced radio relics versus their size, we find that the radio emission overlapping the shocked region in MACS J0744.9+3927 is likely of AGN origin. We argue against the presence of a relic caused by diffusive shock acceleration and suggest that the shock is too weak to accelerate electrons from the intracluster medium.

  2. A tree routing protocol for cognitive radio network

    Directory of Open Access Journals (Sweden)

    Mohammed Hashem

    2017-07-01

    Full Text Available Cognitive Radio (CR technology is an agile solution for spectrum congestion and spectrum access utilization problems that result from the legacy fixed spectrum management policies. CR technology can exploit unused licensed band to meet the increasing demand for radio frequency. The routing process faces many challenges in CR Network (CRN such as the absence of centralized infrastructure, the coordination between the routing module and spectrum management module, in addition to the frequent link failure due to the sudden appearance of PUs. In this paper we propose a Tree routing protocol for cognitive radio network (C-TRP that jointly utilizes the tree routing algorithm with a spectrum management module in routing decisions, and also we proposed a new metric used in taking the best route decisions. In addition, we enhance the traditional tree routing algorithm by using a neighbor table technique that speeds up the forwarding data packets. Moreover, we add a robust recovery module to C-TRP to resume the network in case of the link failure. The main motivation in the design of C-TRP is quick data transmission and maximization of date rates. The performance evaluation is carried out in NS2 simulator. The simulation results proved that C-TRP protocol achieves better performance in terms of average “PDR”, “end-to-end delay” and “routing overhead ratio “compared to “CTBR” and “STOD-RP” routing protocols.

  3. MAC-layer protocol for TCP fairness in Wireless Mesh Networks

    KAUST Repository

    Nawab, Faisal; Jamshaid, Kamran; Shihada, Basem; Ho, Pin-Han

    2012-01-01

    In this paper we study the interactions of TCP and IEEE 802.11 MAC in Wireless Mesh Networks (WMNs). We use a Markov chain to capture the behavior of TCP sessions, particularly the impact on network throughput performance due to the effect of queue

  4. Energy-Efficient Link-Layer Jamming Attacks against Wireless Sensor Network MAC Protocols

    NARCIS (Netherlands)

    Law, Y.W.; van Hoesel, L.F.W.; Doumen, J.M.; Hartel, Pieter H.; Havinga, Paul J.M.; Atluri, V.; Samarati, P.; Ning, P.; Du, W.

    2005-01-01

    A typical wireless sensor node has little protection against radio jamming. The situation becomes worse if energy efficient jamming can be achieved by exploiting knowledge of the data link layer. Encrypting the packets may help prevent the jammer from taking actions based on the content of the

  5. Low-power low-latency MAC protocol for aeronautical applications

    Science.gov (United States)

    Sabater, Jordi; Kluge, Martin; Bovelli, Sergio; Schalk, Josef

    2007-05-01

    This paper describes asynchronous MAC (Medium Access Control) strategies based on the IEEE 802.15.4 physical layer for wireless aeronautical applications where low power and low latency are important requirements as well as security and data integrity. Sensor data is acquired and collected on request, by means of a mobile device, and later stored in a centralized database. In order to have the smallest power consumption the wireless sensor has to remain in deep sleep mode as long as possible and wake up and listen periodically for RF activity. If its unique ID is mentioned in the destination address field, the complete frame is received, processed and replied if necessary. If the detected packet is addressed to another sensor the reception will stop immediately and the wireless sensor will go into deep sleep mode again. Listening instead of sending actively does not 'pollute' the already crowded 2.45GHz spectrum, reduces collisions and increases security. The mobile data concentrator can not be synchronized with all the sensors installed in a distributed environment, therefore smart asynchronous data transmission strategies are needed to reduce latencies and increase throughput. For the considered application, sensors are independent of each other, simply share the medium and together with the data concentrator are organized in a star network topology. The centre of the star is the concentrator which is rarely in range. It coordinates and activates the wireless sensor nodes to collect the measured data.

  6. Performance Analysis of an Optical CDMA MAC Protocol With Variable-Size Sliding Window

    Science.gov (United States)

    Mohamed, Mohamed Aly A.; Shalaby, Hossam M. H.; Abdel-Moety El-Badawy, El-Sayed

    2006-10-01

    A media access control protocol for optical code-division multiple-access packet networks with variable length data traffic is proposed. This protocol exhibits a sliding window with variable size. A model for interference-level fluctuation and an accurate analysis for channel usage are presented. Both multiple-access interference (MAI) and photodetector's shot noise are considered. Both chip-level and correlation receivers are adopted. The system performance is evaluated using a traditional average system throughput and average delay. Finally, in order to enhance the overall performance, error control codes (ECCs) are applied. The results indicate that the performance can be enhanced to reach its peak using the ECC with an optimum number of correctable errors. Furthermore, chip-level receivers are shown to give much higher performance than that of correlation receivers. Also, it has been shown that MAI is the main source of signal degradation.

  7. An Improvement over PBOA MAC Protocol by Considering Link Quality in MANET

    OpenAIRE

    Shariati, Nafiseh; Shirazinia, Amirpasha

    2008-01-01

    We propose a methodology for improving theperformance of Progressive Back Off Algorithm (PBOA)which is a protocol that performs medium access controljointly with power control in Ad-hoc networks.Our method selects the optimum SNR thresholds based onlink quality. It adjusts the role of nodes’ mobility in network throughput. Simulation results show that the improvedprotocol outperforms PBOA without adaptation taken from link quality. Qc 20120131

  8. Adaptive Beaconing in Mobility Aware Clustering Based MAC Protocol for Safety Message Dissemination in VANET

    Directory of Open Access Journals (Sweden)

    Nishu Gupta

    2017-01-01

    Full Text Available Majority of research contributions in wireless access in vehicular environment (WAVE/IEEE 802.11p standard focus on life critical safety-related applications. These applications require regular status update of vehicle’s position referred to as beaconing. Periodic beaconing in vehicle to vehicle communication leads to severe network congestion in the communication channel. The condition worsens under high vehicular density where it impacts reliability and upper bound latency of safety messages. In this paper, WAVE compliant enhancement to the existing IEEE 802.11p protocol is presented which targets prioritized delivery of safety messages while simultaneously provisioning the dissemination of nonsafety messages. Proposed scheme relies on dynamic generation of beacons to mitigate channel congestion and inefficient bandwidth utilization by reducing transmission frequency of beacons. Through the use of clustering mechanism, different beaconing frequencies and different data transmission rates are assigned to prioritize vehicular mobility. Through extensive simulation results, the performance of the proposed approach is evaluated in terms of a wide range of quality of service (QoS parameters for two different transmission ranges. Results show that the proposed protocol provides significant enhancement and stability of the clustered topology in vehicular ad hoc network over existing standard and other protocols with similar applications.

  9. OTN Transport of Baseband Radio Serial Protocols in C-RAN Architecture for Mobile Network Applications

    OpenAIRE

    Checko, Aleksandra; Kardaras, Georgios; Lanzani, Christian Fabio Alessandro; Temple, Dan; Mathiasen, Carsten; Pedersen, Lars A.; Klaps, Bert

    2014-01-01

    This white paper presents a proof of concept implementation of digital baseband radio data transport over Optical Transport Network (OTN) compliant to 3GPP Long Term Evolution – Advanced (LTE-A) standard enabling Cloud Radio Access Network (C-RAN) architecture. The transport between the baseband module and a remote radio module is compliant to Common Public Radio Interface (CPRI) and to the OBSAI reference point 3 - 01 (RP3-01) interface protocols, respectively. The purpose is to demonstrate ...

  10. Protocols for Impulse Radio UWB Ad Hoc Networks

    NARCIS (Netherlands)

    Shi, N.

    2010-01-01

    Ultra Wideband (UWB) technology offers an unprecedented opportunity to further accelerate the evolution of wireless communication and expand the application landscape by enabling outstanding capabilities. UWB radio is fundamentally different from most radio technologies, e.g., Bluetooth, WLAN, etc.

  11. Design and Implementation of a MAC Protocol for Timely and Reliable Delivery of Command and Data in Dynamic Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Phan Van Vinh

    2013-09-01

    Full Text Available This paper proposes and implements a new TDMA-based MAC protocol for providing timely and reliable delivery of data and command for monitoring and control networks. In this kind of network, sensor nodes are required to sense data from the monitoring environment periodically and then send the data to a sink. The sink determines whether the environment is safe or not by analyzing the acquired data. Sometimes, a command or control message is sent from the sink to a particular node or a group of nodes to execute the services or request further interested data. The proposed MAC protocol enables bidirectional communication, controls active and sleep modes of a sensor node to conserve energy, and addresses the problem of load unbalancing between the nodes near a sink and the other nodes. It can improve reliability of communication significantly while extending network lifetime. These claims are supported by the experimental results.

  12. Mac Bible

    CERN Document Server

    Spivey, Dwight

    2009-01-01

    This essential guide answers all your questions on using a Macintosh computer, whether you?re unpacking your very first Mac after switching from a PC or upgrading from an older Mac. You?ll walk through all pre-installed Mac applications, including using Mac OS X, browsing the Web using Safari, downloading music from the iTunes store, troubleshooting Mac-specific problems, organizing photos in iPhoto, organizing calendars in iCal, editing digital video in iMovie, and more.

  13. Multimedia over cognitive radio networks algorithms, protocols, and experiments

    CERN Document Server

    Hu, Fei

    2014-01-01

    PrefaceAbout the EditorsContributorsNetwork Architecture to Support Multimedia over CRNA Management Architecture for Multimedia Communication in Cognitive Radio NetworksAlexandru O. Popescu, Yong Yao, Markus Fiedler , and Adrian P. PopescuPaving a Wider Way for Multimedia over Cognitive Radios: An Overview of Wideband Spectrum Sensing AlgorithmsBashar I. Ahmad, Hongjian Sun, Cong Ling, and Arumugam NallanathanBargaining-Based Spectrum Sharing for Broadband Multimedia Services in Cognitive Radio NetworkYang Yan, Xiang Chen, Xiaofeng Zhong, Ming Zhao, and Jing WangPhysical Layer Mobility Challen

  14. A Conflict-Free Low-Jitter Guaranteed-Rate MAC Protocol for Base-Station Communications in Wireless Mesh Networks

    Science.gov (United States)

    Szymanski, T. H.

    A scheduling algorithm and MAC protocol which provides low-jitter guaranteed-rate (GR) communications between base-stations (BS) in a Wireless Mesh Network (WMN) is proposed. The protocol can provision long-term multimedia services such as VOIP, IPTV, or Video-on-Demand. The time-axis is partitioned into scheduling frames with F time-slots each. A directional antennae scheme is used to provide each directed link with a fixed transmission rate. A protocol such as IntServ is used to provision resources along an end-to-end path of BSs for GR sessions. The Guaranteed Rates between the BSs are then specified in a doubly stochastic traffic rate matrix, which is recursively decomposed to yield a low-jitter GR frame transmission schedule. In the resulting schedule, the end-to-end delay and jitter are small and bounded, and the cell loss rate due to primary scheduling conflicts is zero. For dual-channel WMNs, the MAC protocol can achieve 100% utilization, as well as near-minimal queueing delays and near minimal delay jitter. The scheduling time complexity is O(NFlogNF), where N is the number of BSs. Extensive simulation results are presented.

  15. Quorum system and random based asynchronous rendezvous protocol for cognitive radio ad hoc networks

    Directory of Open Access Journals (Sweden)

    Sylwia Romaszko

    2013-12-01

    Full Text Available This paper proposes a rendezvous protocol for cognitive radio ad hoc networks, RAC2E-gQS, which utilizes (1 the asynchronous and randomness properties of the RAC2E protocol, and (2 channel mapping protocol, based on a grid Quorum System (gQS, and taking into account channel heterogeneity and asymmetric channel views. We show that the combination of the RAC2E protocol with the grid-quorum based channel mapping can yield a powerful RAC2E-gQS rendezvous protocol for asynchronous operation in a distributed environment assuring a rapid rendezvous between the cognitive radio nodes having available both symmetric and asymmetric channel views. We also propose an enhancement of the protocol, which uses a torus QS for a slot allocation, dealing with the worst case scenario, a large number of channels with opposite ranking lists.

  16. Multipath Activity Based Routing Protocol for Mobile ‎Cognitive Radio Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Shereen Omar

    2017-01-01

    Full Text Available Cognitive radio networks improve spectrum utilization by ‎sharing licensed spectrum with cognitive radio devices. In ‎cognitive radio ad hoc networks the routing protocol is one ‎of the most challenging tasks due to the changes in ‎frequency spectrum and the interrupted connectivity ‎caused by the primary user activity. In this paper, a multi‎path activity based routing protocol for cognitive radio ‎network (MACNRP is proposed. The protocol utilizes ‎channel availability and creates multiple node-disjoint ‎routes between the source and destination nodes. The ‎proposed protocol is compared with D2CARP and FTCRP ‎protocols. The performance evaluation is conducted ‎through mathematical analysis and using OPNET ‎simulation. The performance of the proposed protocol ‎achieves an increase in network throughput; besides it ‎decreases the probability of route failure due to node ‎mobility and primary user activity. We have found that the ‎MACNRP scheme results in 50% to 75% reduction in ‎blocking probability and 33% to 78% improvement in ‎network throughput, with a reasonable additional routing ‎overhead and average packet delay. Due to the successful ‎reduction of collision between primary users and ‎cognitive users, the MACNRP scheme results in decreasing ‎the path failure rate by 50% to 87%.‎

  17. Protocols development for security and privacy of radio frequency identification systems

    Science.gov (United States)

    Sabbagha, Fatin

    There are benefits to adopting radio frequency identification (RFID) technology, although there are methods of attack that can compromise the system. This research determined how that may happen and what possible solutions can keep that from happening. Protocols were developed to implement better security. In addition, new topologies were developed to handle the problems of the key management. Previously proposed protocols focused on providing mutual authentication and privacy between readers and tags. However, those protocols are still vulnerable to be attacked. These protocols were analyzed and the disadvantages shown for each one. Previous works assumed that the channels between readers and the servers were secure. In the proposed protocols, a compromised reader is considered along with how to prevent tags from being read by that reader. The new protocols provide mutual authentication between readers and tags and, at the same time, remove the compromised reader from the system. Three protocols are proposed. In the first protocol, a mutual authentication is achieved and a compromised reader is not allowed in the network. In the second protocol, the number of times a reader contacts the server is reduced. The third protocol provides authentication and privacy between tags and readers using a trusted third party. The developed topology is implemented using python language and simulates work to check the efficiency regarding the processing time. The three protocols are implemented by writing codes in C language and then compiling them in MSP430. IAR Embedded workbench is used, which is an integrated development environment with the C/C++ compiler to generate a faster code and to debug the microcontroller. In summary, the goal of this research is to find solutions for the problems on previously proposed protocols, handle a compromised reader, and solve key management problems.

  18. A Power-Efficient Access Point Operation for Infrastructure Basic Service Set in IEEE 802.11 MAC Protocol

    Directory of Open Access Journals (Sweden)

    Hua Ye Ming

    2006-01-01

    Full Text Available Infrastructure-based wireless LAN technology has been widely used in today's personal communication environment. Power efficiency and battery management have been the center of attention in the design of handheld devices with wireless LAN capability. In this paper, a hybrid protocol named improved PCF operation is proposed, which intelligently chooses the access point- (AP- assisted DCF (distributed coordinator function and enhanced PCF (point coordinator function transmission mechanism of IEEE 802.11 protocol in an infrastructure-based wireless LAN environment. Received signal strength indicator (RSSI is used to determine the tradeoff between direct mobile-to-mobile transmission and transmission routed by AP. Based on the estimation, mobile stations can efficiently communicate directly instead of being routed through AP if they are in the vicinity of each other. Furthermore, a smart AP protocol is proposed as extension to the improved PCF operation by utilizing the historical end-to-end delay information to decide the waking up time of mobile stations. Simulation results show that using the proposed protocol, energy consumption of mobile devices can be reduced at the cost of slightly longer end-to-end packet delay compared to traditional IEEE 802.11 PCF protocol. However, in a non-time-critical environment, this option can significantly prolong the operation time of mobile devices.

  19. Performance Analysis of the IEEE 802.11p Multichannel MAC Protocol in Vehicular Ad Hoc Networks.

    Science.gov (United States)

    Song, Caixia

    2017-12-12

    Vehicular Ad Hoc Networks (VANETs) employ multichannel to provide a variety of safety and non-safety applications, based on the IEEE 802.11p and IEEE 1609.4 protocols. The safety applications require timely and reliable transmissions, while the non-safety applications require efficient and high throughput. In the IEEE 1609.4 protocol, operating interval is divided into alternating Control Channel (CCH) interval and Service Channel (SCH) interval with an identical length. During the CCH interval, nodes transmit safety-related messages and control messages, and Enhanced Distributed Channel Access (EDCA) mechanism is employed to allow four Access Categories (ACs) within a station with different priorities according to their criticality for the vehicle's safety. During the SCH interval, the non-safety massages are transmitted. An analytical model is proposed in this paper to evaluate performance, reliability and efficiency of the IEEE 802.11p and IEEE 1609.4 protocols. The proposed model improves the existing work by taking serval aspects and the character of multichannel switching into design consideration. Extensive performance evaluations based on analysis and simulation help to validate the accuracy of the proposed model and analyze the capabilities and limitations of the IEEE 802.11p and IEEE 1609.4 protocols, and enhancement suggestions are given.

  20. Cognitive MAC designs for OSA networks

    CERN Document Server

    Derakhshani, Mahsa

    2014-01-01

    This SpringerBrief presents recent advances in the cognitive MAC designs for opportunistic spectrum access (OSA) networks. It covers the basic MAC functionalities and MAC enhancements of IEEE 802.11. Later chapters discuss the existing MAC protocols for OSA and classify them based on characteristic features. The authors provide new research in adaptive carrier sensing-based MAC designs tailored for OSA, which optimize spectrum utilization and ensure a peaceful coexistence of licensed and unlicensed systems. Analytically devised via optimization and game-theoretic approaches, these adaptive M

  1. A Full-Duplex MAC Tailored for 5G Wireless Networks

    Directory of Open Access Journals (Sweden)

    Lucas de Melo Guimarães

    2018-01-01

    Full Text Available The increasing demands for high-data rate traffic stimulated the development of the fifth-generation (5G mobile networks. The envisioned 5G network is expected to meet its challenge by devising means to further improve spectrum usage. Many alternatives to enhance spectrum usage are being researched, such as massive MIMO, operation in mmWave frequency, cognitive radio, and the employment of full-duplex antennas. Efficient utilization of the potential of any of these technologies faces a set of challenges related to medium access control (MAC schemes. This work focuses on MAC schemes tailored for full-duplex antennas, since they are expected to play a major role in the foreseeable 5G networks. In this context, this paper presents a MAC layer technique to improve total transmission time when full-duplex antennas are employed. Several evaluations in different scenarios are conducted to assess the proposed MAC scheme. Numerical results show that the proposed scheme provides gains up to 156% when compared to a state-of-the-art full-duplex antenna MAC protocol. Compared to traditional half-duplex antenna MAC protocols, the proposed scheme yields gain up to 412%.

  2. A Rate-Adaptive MAC Protocol Based on TCP throughput for Ad Hoc Networks in Fading Channels

    Directory of Open Access Journals (Sweden)

    Shoko Uchida

    2008-10-01

    Full Text Available Wireless technology is becoming a leading option for future Internet access. Transmission Control Protocol (TCP is one of the protocols designed on the basis of the transmission characteristics in wired networks. It is known that the TCP performance deteriorates drastically under a wireless communication environment. On the other hand, many wireless networking standards such as IEEE 802.11a, 802.11b, and 802.11g have multirate capability. Therefore, adaptive rate control methods have been proposed for ad hoc networks. However, almost methods require the modification of the request to send (RTS and clear to send (CTS packets. Therefore, the conventional methods are not compatible with the standardized system. In this paper, we propose adaptive rate control mechanisms for ad hoc networks. Our mechanisms are based on the RTS/CTS mechanisms. However, no modifications to the RTS and CTS packets are required in the proposed method. Therefore, our proposed method can attempt to satisfy the conventional IEEE 802.11 standards. Moreover, an adequate transmission rate is selected based on an estimated TCP throughput performance. From simulation results, it is observed that the proposed method can improve the throughput performance without any modification of packet structures.

  3. Cognitive radio networks medium access control for coexistence of wireless systems

    CERN Document Server

    Bian, Kaigui; Gao, Bo

    2014-01-01

    This book gives a comprehensive overview of the medium access control (MAC) principles in cognitive radio networks, with a specific focus on how such MAC principles enable different wireless systems to coexist in the same spectrum band and carry out spectrum sharing.  From algorithm design to the latest developments in the standards and spectrum policy, readers will benefit from leading-edge knowledge of how cognitive radio systems coexist and share spectrum resources.  Coverage includes cognitive radio rendezvous, spectrum sharing, channel allocation, coexistence in TV white space, and coexistence of heterogeneous wireless systems.   • Provides a comprehensive reference on medium access control (MAC)-related problems in the design of cognitive radio systems and networks; • Includes detailed analysis of various coexistence problems related to medium access control in cognitive radio networks; • Reveals novel techniques for addressing the challenges of coexistence protocol design at a higher level ...

  4. I-MAC: an incorporation MAC for wireless sensor networks

    Science.gov (United States)

    Zhao, Jumin; Li, Yikun; Li, Dengao; Lin, Xiaojie

    2017-11-01

    This paper proposes an innovative MAC protocol called I-MAC. Protocol for wireless sensor networks, which combines the advantages of collision tolerance and collision cancellation. The protocol increases the number of antenna in wireless sensor nodes. The purpose is to monitor the occurrence of packet collisions by increasing the number of antenna in real time. The built-in identity structure is used in the frame structure in order to help the sending node to identify the location of the receiving node after a data packet collision is detected. Packets can be recovered from where the conflict occurred. In this way, we can monitor the conflict for a fixed period of time. It can improve the channel utilisation through changing the transmission probability of collision nodes and solve the problem of hidden terminal through collision feedback mechanism. We have evaluated our protocol. Our results show that the throughput of I-MAC is 5 percentage points higher than that of carrier sense multiple access/collision notification. The network utilisation of I-MAC is more than 92%.

  5. On PHY and MAC Performance in Body Sensor Networks

    Directory of Open Access Journals (Sweden)

    Higgins Henry

    2009-01-01

    Full Text Available Abstract This paper presents an empirical investigation on the performance of body implant communication using radio frequency (RF technology. In body implant communication, the electrical properties of the body influence the signal propagation in several ways. We use a Perspex body model (30 cm diameter, 80 cm height and 0.5 cm thickness filled with a liquid that mimics the electrical properties of the basic body tissues. This model is used to observe the effects of body tissue on the RF communication. We observe best performance at 3cm depth inside the liquid. We further present a simulation study of several low-power MAC protocols for an on-body sensor network and discuss the derived results. Also, the traditional preamble-based TMDA protocol is extended towards a beacon-based TDMA protocol in order to avoid preamble collision and to ensure low-power communication.

  6. On PHY and MAC Performance in Body Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sana Ullah

    2009-01-01

    Full Text Available This paper presents an empirical investigation on the performance of body implant communication using radio frequency (RF technology. In body implant communication, the electrical properties of the body influence the signal propagation in several ways. We use a Perspex body model (30 cm diameter, 80 cm height and 0.5 cm thickness filled with a liquid that mimics the electrical properties of the basic body tissues. This model is used to observe the effects of body tissue on the RF communication. We observe best performance at 3cm depth inside the liquid. We further present a simulation study of several low-power MAC protocols for an on-body sensor network and discuss the derived results. Also, the traditional preamble-based TMDA protocol is extended towards a beacon-based TDMA protocol in order to avoid preamble collision and to ensure low-power communication.

  7. The Optimization of the Data Packet Length in Adaptive Radio Networks

    Directory of Open Access Journals (Sweden)

    Anatolii P. Voiter

    2017-10-01

    Full Text Available Background. Development of methods and means of the adaptive management of the radio networks bandwidth with competitive access to the radio channel. Objective. The aim of the paper is to determine the packet length effect on the effective radio networks transmission rate with taking into account the parameters, formats, and procedures of the physical and link levels at using the MAC protocol with a rigid strategy of competitive access to the radio channel. Methods. The goal is achieved by creating and analyzing the mathematical model of the effective transmission rate in radio networks. The model is described by the equation for the effective transmission rate, which is the function of both the probability of the conflict-free transmission of the MAC protocol and the coefficient of the data packet size deviation from the optimal for LLC protocol. Results. It is proved that there is the optimal deviation of the data packet length for each MAC protocol traffic intensity value, which provides the most effective transfer rate. This makes the possibility for adaptive management of the radio bandwidth by applying a pre-calculated deviation of the data packet size in dependence on the traffic intensity. Conclusions. The proposed mathematical model is the tool for calculation of both the radio bandwidth network capacity and the optimal deviation of the data packet length at adaptive management of competitive access to a radio channel with a rigid strategy at conditions of the significant fluctuation in traffic intensity.

  8. LAMAN: Load Adaptable MAC for Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Realp Marc

    2005-01-01

    Full Text Available In mobile ad hoc radio networks, mechanisms on how to access the radio channel are extremely important in order to improve network efficiency. In this paper, the load adaptable medium access control for ad hoc networks (LAMAN protocol is described. LAMAN is a novel decentralized multipacket MAC protocol designed following a cross-layer approach. Basically, this protocol is a hybrid CDMA-TDMA-based protocol that aims at throughput maximization in multipacket communication environments by efficiently combining contention and conflict-free protocol components. Such combination of components is used to adapt the nodes' access priority to changes on the traffic load while, at the same time, accounting for the multipacket reception (MPR capability of the receivers. A theoretical analysis of the system is developed presenting closed expressions of network throughput and packet delay. By simulations the validity of our analysis is shown and the performances of a LAMAN-based system and an Aloha-CDMA-based one are compared.

  9. Q-Learning and p-persistent CSMA based rendezvous protocol for cognitive radio networks operating with shared spectrum activity

    Science.gov (United States)

    Watson, Clifton L.; Biswas, Subir

    2014-06-01

    With an increasing demand for spectrum, dynamic spectrum access (DSA) has been proposed as viable means for providing the flexibility and greater access to spectrum necessary to meet this demand. Within the DSA concept, unlicensed secondary users temporarily "borrow" or access licensed spectrum, while respecting the licensed primary user's rights to that spectrum. As key enablers for DSA, cognitive radios (CRs) are based on software-defined radios which allow them to sense, learn, and adapt to the spectrum environment. These radios can operate independently and rapidly switch channels. Thus, the initial setup and maintenance of cognitive radio networks are dependent upon the ability of CR nodes to find each other, in a process known as rendezvous, and create a link on a common channel for the exchange of data and control information. In this paper, we propose a novel rendezvous protocol, known as QLP, which is based on Q-learning and the p-persistent CSMA protocol. With the QLP protocol, CR nodes learn which channels are best for rendezvous and thus adapt their behavior to visit those channels more frequently. We demonstrate through simulation that the QLP protocol provides a rendevous capability for DSA environments with different dynamics of PU activity, while attempting to achieve the following performance goals: (1) minimize the average time-to-rendezvous, (2) maximize system throughput, (3) minimize primary user interference, and (4) minimize collisions among CR nodes.

  10. Windows for Intel Macs

    CERN Document Server

    Ogasawara, Todd

    2008-01-01

    Even the most devoted Mac OS X user may need to use Windows XP, or may just be curious about XP and its applications. This Short Cut is a concise guide for OS X users who need to quickly get comfortable and become productive with Windows XP basics on their Macs. It covers: Security Networking ApplicationsMac users can easily install and use Windows thanks to Boot Camp and Parallels Desktop for Mac. Boot Camp lets an Intel-based Mac install and boot Windows XP on its own hard drive partition. Parallels Desktop for Mac uses virtualization technology to run Windows XP (or other operating systems

  11. Macs for dummies

    CERN Document Server

    Baig, Edward C

    2014-01-01

    Get the most out of your Mac with this comprehensive guide Macs For Dummies, 13th Edition is the ultimate guide to your Mac, fully updated to include information about the latest updates. The book walks you through troubleshooting, syncing mobile devices, integrating Windows, and more, so you can take advantage of everything Macs have to offer. Whether you're a new user, a recent convert, or you just want to get the most out of your Mac, this book puts all the information you need in one place. Discover what makes Macs superior computing machines. Learn the basics, from mastering the Dock and

  12. Energy-Efficient Boarder Node Medium Access Control Protocol for Wireless Sensor Networks

    Science.gov (United States)

    Razaque, Abdul; Elleithy, Khaled M.

    2014-01-01

    This paper introduces the design, implementation, and performance analysis of the scalable and mobility-aware hybrid protocol named boarder node medium access control (BN-MAC) for wireless sensor networks (WSNs), which leverages the characteristics of scheduled and contention-based MAC protocols. Like contention-based MAC protocols, BN-MAC achieves high channel utilization, network adaptability under heavy traffic and mobility, and low latency and overhead. Like schedule-based MAC protocols, BN-MAC reduces idle listening time, emissions, and collision handling at low cost at one-hop neighbor nodes and achieves high channel utilization under heavy network loads. BN-MAC is particularly designed for region-wise WSNs. Each region is controlled by a boarder node (BN), which is of paramount importance. The BN coordinates with the remaining nodes within and beyond the region. Unlike other hybrid MAC protocols, BN-MAC incorporates three promising models that further reduce the energy consumption, idle listening time, overhearing, and congestion to improve the throughput and reduce the latency. One of the models used with BN-MAC is automatic active and sleep (AAS), which reduces the ideal listening time. When nodes finish their monitoring process, AAS lets them automatically go into the sleep state to avoid the idle listening state. Another model used in BN-MAC is the intelligent decision-making (IDM) model, which helps the nodes sense the nature of the environment. Based on the nature of the environment, the nodes decide whether to use the active or passive mode. This decision power of the nodes further reduces energy consumption because the nodes turn off the radio of the transceiver in the passive mode. The third model is the least-distance smart neighboring search (LDSNS), which determines the shortest efficient path to the one-hop neighbor and also provides cross-layering support to handle the mobility of the nodes. The BN-MAC also incorporates a semi

  13. Energy-efficient boarder node medium access control protocol for wireless sensor networks.

    Science.gov (United States)

    Razaque, Abdul; Elleithy, Khaled M

    2014-03-12

    This paper introduces the design, implementation, and performance analysis of the scalable and mobility-aware hybrid protocol named boarder node medium access control (BN-MAC) for wireless sensor networks (WSNs), which leverages the characteristics of scheduled and contention-based MAC protocols. Like contention-based MAC protocols, BN-MAC achieves high channel utilization, network adaptability under heavy traffic and mobility, and low latency and overhead. Like schedule-based MAC protocols, BN-MAC reduces idle listening time, emissions, and collision handling at low cost at one-hop neighbor nodes and achieves high channel utilization under heavy network loads. BN-MAC is particularly designed for region-wise WSNs. Each region is controlled by a boarder node (BN), which is of paramount importance. The BN coordinates with the remaining nodes within and beyond the region. Unlike other hybrid MAC protocols, BN-MAC incorporates three promising models that further reduce the energy consumption, idle listening time, overhearing, and congestion to improve the throughput and reduce the latency. One of the models used with BN-MAC is automatic active and sleep (AAS), which reduces the ideal listening time. When nodes finish their monitoring process, AAS lets them automatically go into the sleep state to avoid the idle listening state. Another model used in BN-MAC is the intelligent decision-making (IDM) model, which helps the nodes sense the nature of the environment. Based on the nature of the environment, the nodes decide whether to use the active or passive mode. This decision power of the nodes further reduces energy consumption because the nodes turn off the radio of the transceiver in the passive mode. The third model is the least-distance smart neighboring search (LDSNS), which determines the shortest efficient path to the one-hop neighbor and also provides cross-layering support to handle the mobility of the nodes. The BN-MAC also incorporates a semi

  14. Energy-Efficient Boarder Node Medium Access Control Protocol for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Abdul Razaque

    2014-03-01

    Full Text Available This paper introduces the design, implementation, and performance analysis of the scalable and mobility-aware hybrid protocol named boarder node medium access control (BN-MAC for wireless sensor networks (WSNs, which leverages the characteristics of scheduled and contention-based MAC protocols. Like contention-based MAC protocols, BN-MAC achieves high channel utilization, network adaptability under heavy traffic and mobility, and low latency and overhead. Like schedule-based MAC protocols, BN-MAC reduces idle listening time, emissions, and collision handling at low cost at one-hop neighbor nodes and achieves high channel utilization under heavy network loads. BN-MAC is particularly designed for region-wise WSNs. Each region is controlled by a boarder node (BN, which is of paramount importance. The BN coordinates with the remaining nodes within and beyond the region. Unlike other hybrid MAC protocols, BN-MAC incorporates three promising models that further reduce the energy consumption, idle listening time, overhearing, and congestion to improve the throughput and reduce the latency. One of the models used with BN-MAC is automatic active and sleep (AAS, which reduces the ideal listening time. When nodes finish their monitoring process, AAS lets them automatically go into the sleep state to avoid the idle listening state. Another model used in BN-MAC is the intelligent decision-making (IDM model, which helps the nodes sense the nature of the environment. Based on the nature of the environment, the nodes decide whether to use the active or passive mode. This decision power of the nodes further reduces energy consumption because the nodes turn off the radio of the transceiver in the passive mode. The third model is the least-distance smart neighboring search (LDSNS, which determines the shortest efficient path to the one-hop neighbor and also provides cross-layering support to handle the mobility of the nodes. The BN-MAC also incorporates a semi

  15. Mycobacterium Avium Complex (MAC)

    Science.gov (United States)

    ... sweat, and saliva red-orange (may stain contact lenses); can interfere with birth control pills. Many drug interactions. CAN MAC BE PREVENTED? The bacteria that cause MAC are very common. It is ...

  16. Mac OS X Forensics

    Science.gov (United States)

    Craiger, Philip; Burke, Paul

    This paper describes procedures for conducting forensic examinations of Apple Macs running Mac OS X. The target disk mode is used to create a forensic duplicate of a Mac hard drive and preview it. Procedures are discussed for recovering evidence from allocated space, unallocated space, slack space and virtual memory. Furthermore, procedures are described for recovering trace evidence from Mac OS X default email, web browser and instant messaging applications, as well as evidence pertaining to commands executed from a terminal.

  17. Enterprise Mac administrators guide

    CERN Document Server

    Smith, William

    2015-01-01

    IT departments everywhere will be integrating Macs and Mac OS X into their IT infrastructure and this book will tell them how to do it. It will serve as an authoritative, useful and frequently referenced book on Mac OS X administration.

  18. Enterprise Mac Administrator's Guide

    CERN Document Server

    Edge, Charles; Hunter, Beau

    2009-01-01

    Charles Edge, Zack Smith, and Beau Hunter provide detailed explanations of the technology required for large-scale Mac OS X deployments and show you how to integrate it with other operating systems and applications. Enterprise Mac Administrator's Guide addresses the growing size and spread of Mac OS X deployments in corporations and institutions worldwide. In some cases, this is due to the growth of traditional Mac environments, but for the most part it has to do with "switcher" campaigns, where Windows and/or Linux environments are migrating to Mac OS X. However, there is a steep cu

  19. Mac Security Bible

    CERN Document Server

    Kissell, Joe

    2010-01-01

    Your essential, no-holds-barred guide to Mac security threats and solutions. Myth number one: Macs are safer than PCs. Not really, says author Joe Kissell, named one of MacTech's "25 Most Influential People" in the Mac community for 2008. In this timely guide, he not only takes you beyond the myths, he also delves into the nitty-gritty of each potential threat, helping you weigh the pros and cons of the solutions you might choose. Learn to measure risk versus inconvenience, make informed decisions, and protect your Mac computers, your privacy, and your data with this essential guide.

  20. Mac at Work

    CERN Document Server

    Sparks, David

    2011-01-01

    Bridge the gap between using a Mac at home and at the office. Now that you love your Mac at home, you want to use one at the office without missing a beat of productivity or professionalism. This unique guide shows you how.  You'll find best Mac business practices for handling word processing, spreadsheet and presentation creation, task and project management, and graphics. The book also explores topics such as hardware maintenance, how to synchronize with multiple computers, data backup, and communication with Windows networks.: Covers the nuts and bolts of using a Mac at work, including sync

  1. OTN Transport of Baseband Radio Serial Protocols in C-RAN Architecture for Mobile Network Applications

    DEFF Research Database (Denmark)

    Checko, Aleksandra; Kardaras, Georgios; Lanzani, Christian Fabio Alessandro

    This white paper presents a proof of concept implementation of digital baseband radio data transport over Optical Transport Network (OTN) compliant to 3GPP Long Term Evolution – Advanced (LTE-A) standard enabling Cloud Radio Access Network (C-RAN) architecture. The transport between the baseband ...

  2. Enterprise Mac Security Mac OS X Snow Leopard Security

    CERN Document Server

    Edge, Stephen Charles; Hunter, Beau; Sullivan, Gene; LeBlanc, Dee-Ann

    2010-01-01

    A common misconception in the Mac community is that Mac's operating system is more secure than others. While this might be true in certain cases, security on the Mac is still a crucial issue. When sharing is enabled or remote control applications are installed, Mac OS X faces a variety of security threats. Enterprise Mac Security: Mac OS X Snow Leopard is a definitive, expert-driven update of the popular, slash-dotted first edition and was written in part as a companion to the SANS Institute course for Mac OS X. It contains detailed Mac OS X security information, and walkthroughs on securing s

  3. Enterprise Mac Managed Preferences

    CERN Document Server

    Marczak, Edward

    2010-01-01

    Many systems administrators on the Mac need a way to manage machine configuration after initial setup and deployment. Apple's Managed Preferences system (also known as MCX) is under-documented, often misunderstood, and sometimes outright unknown by sys admins. MCX is usually deployed in conjunction with an OS X server, but it can also be used in Windows environments or where no dedicated server exists at all. Enterprise Mac Managed Preferences is the definitive guide to Apple's Managed Client technology. With this book, you'll get the following: * An example-driven guide to Mac OS X Managed Pr

  4. An ultra low-power and traffic-adaptive medium access control protocol for wireless body area network.

    Science.gov (United States)

    Ullah, Sana; Kwak, Kyung Sup

    2012-06-01

    Wireless Body Area Network (WBAN) consists of low-power, miniaturized, and autonomous wireless sensor nodes that enable physicians to remotely monitor vital signs of patients and provide real-time feedback with medical diagnosis and consultations. It is the most reliable and cheaper way to take care of patients suffering from chronic diseases such as asthma, diabetes and cardiovascular diseases. Some of the most important attributes of WBAN is low-power consumption and delay. This can be achieved by introducing flexible duty cycling techniques on the energy constraint sensor nodes. Stated otherwise, low duty cycle nodes should not receive frequent synchronization and control packets if they have no data to send/receive. In this paper, we introduce a Traffic-adaptive MAC protocol (TaMAC) by taking into account the traffic information of the sensor nodes. The protocol dynamically adjusts the duty cycle of the sensor nodes according to their traffic-patterns, thus solving the idle listening and overhearing problems. The traffic-patterns of all sensor nodes are organized and maintained by the coordinator. The TaMAC protocol is supported by a wakeup radio that is used to accommodate emergency and on-demand events in a reliable manner. The wakeup radio uses a separate control channel along with the data channel and therefore it has considerably low power consumption requirements. Analytical expressions are derived to analyze and compare the performance of the TaMAC protocol with the well-known beacon-enabled IEEE 802.15.4 MAC, WiseMAC, and SMAC protocols. The analytical derivations are further validated by simulation results. It is shown that the TaMAC protocol outperforms all other protocols in terms of power consumption and delay.

  5. Multichannel MAC Layer In Mobile Ad—Hoc Network

    Science.gov (United States)

    Logesh, K.; Rao, Samba Siva

    2010-11-01

    This paper we presented the design objectives and technical challenges in Multichannel MAC protocols in Mobile Ad-hoc Network. In IEEE 802.11 a/b/g standards allow use of multiple channels, only a single channel is popularly used, due to the lack of efficient protocols that enable use of Multiple Channels. Even though complex environments in ad hoc networks require a combined control of physical (PHY) and medium access control (MAC) layers resources in order to optimize performance. And also we discuss the characteristics of cross-layer frame and give a multichannel MAC approach.

  6. Advertisement-Based Energy Efficient Medium Access Protocols for Wireless Sensor Networks

    Science.gov (United States)

    Ray, Surjya Sarathi

    One of the main challenges that prevents the large-scale deployment of Wireless Sensor Networks (WSNs) is providing the applications with the required quality of service (QoS) given the sensor nodes' limited energy supplies. WSNs are an important tool in supporting applications ranging from environmental and industrial monitoring, to battlefield surveillance and traffic control, among others. Most of these applications require sensors to function for long periods of time without human intervention and without battery replacement. Therefore, energy conservation is one of the main goals for protocols for WSNs. Energy conservation can be performed in different layers of the protocol stack. In particular, as the medium access control (MAC) layer can access and control the radio directly, large energy savings is possible through intelligent MAC protocol design. To maximize the network lifetime, MAC protocols for WSNs aim to minimize idle listening of the sensor nodes, packet collisions, and overhearing. Several approaches such as duty cycling and low power listening have been proposed at the MAC layer to achieve energy efficiency. In this thesis, I explore the possibility of further energy savings through the advertisement of data packets in the MAC layer. In the first part of my research, I propose Advertisement-MAC or ADV-MAC, a new MAC protocol for WSNs that utilizes the concept of advertising for data contention. This technique lets nodes listen dynamically to any desired transmission and sleep during transmissions not of interest. This minimizes the energy lost in idle listening and overhearing while maintaining an adaptive duty cycle to handle variable loads. Additionally, ADV-MAC enables energy efficient MAC-level multicasting. An analytical model for the packet delivery ratio and the energy consumption of the protocol is also proposed. The analytical model is verified with simulations and is used to choose an optimal value of the advertisement period

  7. Radio and chemioinduced oral mucositis treatment: comparison between conventional drug protocol and treatments with low intensity lasers

    International Nuclear Information System (INIS)

    Alencar, Anelise Ribeiro Peixoto

    2011-01-01

    In this clinical study verified the effects of low intensity laser in the prevention and treatment of oral mucositis radio and/or chemical induced. Thirty one patients with head and neck cancer were selected before being submitted to cancer exclusive radiotherapy or radio and associated chemotherapy. The patients were distributed into three randomly groups as follows: group 1- (control) conventional medicine treatment; group 2 - conventional medicine treatment and daily laser therapy as soon as grade two oral mucositis appeared; group 3 - conventional medicine treatment and daily laser therapy to be initiated immediately before radiotherapy sessions.The irradiation parameters were: wavelength of 660nm, potency of 100mW, continuous mode, punctual application, 2J energy on thirty pre-determined 30 points, with 20s of exposure per point. The control group received medical treatment which consisted in using a set of preventive and therapeutic approach for acute radiation-induced adverse effects. Results were evaluated observing occurrence and grade of oral mucositis, score of pain, loss of body mass, use of nasogastric sound line, internment and interruption of oncologic treatment due to oral mucositis. The results showed that the preventive protocol as used was the most effective in prevention and treatment of oral mucositis and that its daily application contributed in relieving the painful symptomatology so collaborating to maintain and/or bettering the life quality of oncologic patients. (author)

  8. QL-MAC : a Q-learning based MAC for wireless sensor networks

    NARCIS (Netherlands)

    Galzarano, S.; Liotta, A.; Fortino, G.; Aversa, R.; Kolodziej, J.; Zhang, J.; Amato, F.; Fortino, G.

    2013-01-01

    WSNs are becoming an increasingly attractive technology thanks to the significant benefits they can offer to a wide range of application domains. Extending the system lifetime while preserving good network performance is one of the main challenges in WSNs. In this paper, a novel MAC protocol

  9. MAC calorimeters and applications

    International Nuclear Information System (INIS)

    MAC Collaboration.

    1982-03-01

    The MAC detector at PEP features a large solid-angle electromagnetic/hadronic calorimeter system, augmented by magnetic charged-particle tracking, muon analysis and scintillator triggering. Its implementation in the context of electron-positron annihilation physics is described, with emphasis on the utilization of calorimetry

  10. Florence Jessie Mac Williams

    Indian Academy of Sciences (India)

    CPMGIKAlBGE-340/2003-05. Resonance - January 2005. Licenced to post WPP No.6 RT Nagar Postoffice. Florence Jessie Mac Williams. (1917 - 1990). Registered with Registrar of Newspapers in India vide Regn. No. 66273/96. ISSN 0971-8044. Price per copy: Rs 40.

  11. Scheduled MAC in Beacon Overlay Networks for Underwater Localization and Time-Synchronization

    NARCIS (Netherlands)

    van Kleunen, W.A.P.; Meratnia, Nirvana; Havinga, Paul J.M.

    2011-01-01

    In this article we introduce a MAC protocol designed for underwater localization and time-synchronisation. The MAC protocol assumes a network of static reference nodes and allows blind nodes to be localized by listening-only to the beacon messages. Such a system is known to be very scalable. We show

  12. iMac pocket genius

    CERN Document Server

    Hart-Davis, Guy

    2010-01-01

    If you want to get the very most out of your iMac, put this savvy Portable Genius guide to work. Want to make the most of the new Magic Mouse and the latest iLife apps? Set up a wireless network using your iMac's AirPort card? Watch television on your iMac, or show iMac videos and movies on your television? You'll find cool and useful Genius tips, full-color screenshots, and pages of easy-to-access shortcuts and tools that will save you time and let you enjoy your iMac to the max.

  13. MacBook for dummies

    CERN Document Server

    Chambers , Mark L

    2014-01-01

    Make friends with your MacBook the fun and easy way! Ultra-light, ultra-fast, and ultra-powerful, the MacBook is the coolest laptop in town, and longtime Mac guru Mark L. Chambers is just the guy to help you get to know your MacBook in no time. Take a closer look at the latest features, get the lowdown on OS X, unleash your creative forces with iLife, take care of business with the iWork applications, and sync it all with iCloud with the expert advice in this bestselling MacBook guide. Whether this is your first MacBook or your first laptop, period, you''ll learn to navigate the Mac desktop, c

  14. Macs For Dummies, Pocket Edition

    CERN Document Server

    Baig, Edward C

    2011-01-01

    The fun and easy way to make the most of your wonderful Mac. Simply Mac-nificent — all the cool things your Mac can do! This handy guide helps you figure out the nuts and bolts of your Mac. Navigate the Mac desktop, use the Safari Web browser to surf the Internet, e-mail photos to friends and family, create and print documents, rip audio CDs, and more. The fun begins right here!. Open the book and find: How to set up and configure your Mac; Tips for getting around on the Mac desktop; Steps for setting up an e-mail account and browsing the Internet; Details about the free programs that come wit

  15. iMac portable genius

    CERN Document Server

    Hart-Davis, Guy

    2010-01-01

    The most up-to-date coverage on the latest iMac advice, tools, and shortcuts Cool and useful tips, full-color screenshots, and savvy advice show you how to get the most out of your iMac. Fully updated to cover the iMac's latest features and capabilities, this guide is packed with indispensible information on iLife '09 and Mac OS X Snow Leopard, and shows you how to customize your iMac in a way that it will work best for you.Explores all the bells and whistles of the iMac, including the new Magic Mouse, iLife apps such as iPhoto and iMovie, and Mac OS X Snow LeopardShows yo

  16. Energy-Efficient Boarder Node Medium Access Control Protocol for Wireless Sensor Networks

    OpenAIRE

    Razaque, Abdul; Elleithy, Khaled M.

    2014-01-01

    This paper introduces the design, implementation, and performance analysis of the scalable and mobility-aware hybrid protocol named boarder node medium access control (BN-MAC) for wireless sensor networks (WSNs), which leverages the characteristics of scheduled and contention-based MAC protocols. Like contention-based MAC protocols, BN-MAC achieves high channel utilization, network adaptability under heavy traffic and mobility, and low latency and overhead. Like schedule-based MAC protocols,...

  17. Modeling MAC layer for powerline communications networks

    Science.gov (United States)

    Hrasnica, Halid; Haidine, Abdelfatteh

    2001-02-01

    The usage of electrical power distribution networks for voice and data transmission, called Powerline Communications, becomes nowadays more and more attractive, particularly in the telecommunication access area. The most important reasons for that are the deregulation of the telecommunication market and a fact that the access networks are still property of former monopolistic companies. In this work, first we analyze a PLC network and system structure as well as a disturbance scenario in powerline networks. After that, we define a logical structure of the powerline MAC layer and propose the reservation MAC protocols for the usage in the PLC network which provides collision free data transmission. This makes possible better network utilization and realization of QoS guarantees which can make PLC networks competitive to other access technologies.

  18. iMac for dummies

    CERN Document Server

    Chambers, Mark L

    2014-01-01

    Do it all with your iMac and this bestselling For Dummies guide! You're still a little giddy from finally scoring your new iMac, and you can't wait to get started. Even if you're already in love with your iMac, it helps to have a little guidance to really get the most out of this ultimate all-in-one computer. This updated edition of iMac For Dummies is the ideal way to learn the iMac fundamentals from setting up and personalizing your machine to importing files, making FaceTime video calls, surfing the web, using your favorite programs and apps, and everything in between. Trusted Mac guru Mark

  19. Learn Excel 2011 for Mac

    CERN Document Server

    Hart-Davis, Guy

    2011-01-01

    Microsoft Excel 2011 for Mac OS X is a powerful application, but many of its most impressive features can be difficult to find. Learn Excel 2011 for Mac by Guy Hart-Davis is a practical, hands-on approach to learning all of the details of Excel 2011 in order to get work done efficiently on Mac OS X. From using formulas and functions to creating databases, from analyzing data to automating tasks, you'll learn everything you need to know to put this powerful application to use for a variety of tasks. What you'll learn * The secrets of the Excel for Mac interface! * How to create effective workbo

  20. Mac Leod's syndrome

    International Nuclear Information System (INIS)

    Schad, M.; Danesi, C.; Ricci, R.; Galluzzi, S.; Coviello, G.

    1988-01-01

    Mac Leod's syndrome is a rarely diagnosed disease; that is why an accurate differential diagnosis is needed by means of radiological imaging. This paper is aimed at discussing the differential diagnosis, with a special emphasis on the pathogenesis of the syndrome. The phenomenon of air trapping in absence of central bronchial lesions is a typical radiographic finding. Chest X-ray is performed in both inspiration and expiration. Posterior oblique tomography at 55 grade centigrade of the effected side is also performed. Diffuse bronchiolitis obliterans in infancy or early childhood ia widely accepted pathogenetic pattern. Pulmonary hypoventilation causes vasoconstriction and underdevelopment of pulmonary vessels, that are reduced in caliber. Differential diagnosis includes all the diseases resulting in pulmonary hyperlucency, i.e. pulmonary and pleural alterations, and skeletal anomalies

  1. Windowsista Mac-maailmaan

    OpenAIRE

    Sirkiä, Noora-Maria

    2010-01-01

    Nykyään yhä useampi harkitsee erilaisista syistä käyttöjärjestelmän vaihtamista tutusta Windowsista johonkin muuhun käyttöjärjestelmään. Applen Macintosh-tietokoneiden mukana tuleva Mac OS X -käyttöjärjestelmä on hyvä vaihtoehto Windowsille. Ihmiset siirtyvät siihen mm. tietoturvaseikkojen, luotettavuuden, ohjelmiston sekä Applen koneiden ja käyttöjärjestelmän ulkomuodon takia. Microsoftin tuotteista ei myöskään tarvitse luopua kokonaan, sillä monista tutuista Microsoftin ohjelmista (esim. Mi...

  2. iMac for dummies

    CERN Document Server

    Chambers, Mark L

    2012-01-01

    The bestselling guide to the ultimate all-in-one computer—now updated and revised throughout! If you're looking for speed, performance, and power, the iMac is the ultimate all-in-one computer. From its superior performance, powerful operating system, and amazing applications, the iMac is one awesome machine, and the fun, friendly, and approachable style of iMac For Dummies is an ideal way to get started with the basics. You'll learn the fundamentals of the iMac including setting up and customizing your iMac and the software that comes with it, importing files from your old computer, send

  3. Definition and specification of "CANlike" protocols in the context of wireless networks

    OpenAIRE

    Juanole , Guy; Mouney , Gérard

    2015-01-01

    Rapport LAAS n° 15276; The implementation of distributed real-time applications on wireless networks constitutes today a new important challenge and, in this context, the MAC protocols, which implement the frame exchange scheduling, have an essential role. This paper is precisely concerned by the specification of such MAC protocols. We specify MAC protocols called CANlike protocols because they are inspired by the MAC protocol of the network CAN which is a wired network. The presentation made...

  4. Gotcha! Macs lose their innocence

    CERN Multimedia

    Computer Security Team

    2012-01-01

    Still believe your Mac is secure because Microsoft PCs fall prey to viruses and worms but Macs don’t? Time to wake up! This year has seen the first major compromise of Macs worldwide*. How is yours doing?   The “Flashback” Trojan is affecting Apple’s own variant of Java and compromises Macs via so-called drive-by infections, i.e. when you visit an appropriately prepared (infected!) website - and this might not necessarily be a site with questionable contents, but could well be a popular, reputable one. Security Companies worldwide have been monitoring this particular Trojan for a while and have estimated that more than half a million Macs were compromised. Connected to a few central command and control servers, the compromised Macs were then supporting the malicious activity of the bad guys! Fortunately, the security companies have now been able to take over those command and control servers and stop their destructive drive. So, Mac users, face the f...

  5. Java and Mac OS X

    CERN Document Server

    Davis, T Gene

    2010-01-01

    Learn the guidelines of integrating Java with native Mac OS X applications with this Devloper Reference book. Java is used to create nearly every type of application that exists and is one of the most required skills of employers seeking computer programmers. Java code and its libraries can be integrated with Mac OS X features, and this book shows you how to do just that. You'll learn to write Java programs on OS X and you'll even discover how to integrate them with the Cocoa APIs.: Shows how Java programs can be integrated with any Mac OS X feature, such as NSView widgets or screen savers; Re

  6. Mac Programming for Absolute Beginners

    CERN Document Server

    Wang, Wallace

    2011-01-01

    Want to learn how to program on your Mac? Not sure where to begin? Best-selling author Wallace Wang will explain how to get started with Cocoa, Objective-C, and Xcode. Whether you are an experienced Windows coder moving to the Mac, or you are completely new to programming, you'll see how the basic design of a Mac OS X program works, how Objective-C differs from other languages you may have used, and how to use the Xcode development environment. Most importantly, you'll learn how to use elements of the Cocoa framework to create windows, store data, and respond to users in your own Mac programs.

  7. Alistair William MacDonald.

    Science.gov (United States)

    Callegari, Angus

    2018-01-06

    A devoted family man and churchgoer, Alistair MacDonald was a meticulous vet with a great sense of humour. Having served in the RAF during the Second World War, he had plenty of stories to tell. British Veterinary Association.

  8. Fiverr MacGyver

    Science.gov (United States)

    Hut, Rolf; van de Giesen, Nick; Larson, Martha

    2014-05-01

    Crowdsourcing has become popular over the past years, also for scientific endeavors. There are many Citizen Science projects and crowdfunding platforms, such as Kickstarter, that are make helpful contributions to moving environmental science forward. An interesting underused source of useful crowd-derived contributions to research is the website Fiverr.com. On this platform, thousands of people, acting as small-scale freelance contractors, offer their skills in the form of services. The platform offers a chance for people to take a hobby, skill, or pastime and make it something more by reaching out to a wider audience and by receiving a payment in return for services. As is typical of other crowdsourcing platforms, the tasks are small and usually self contained. As the name Fiverr suggests, offers start at US5 to provide a particular service. Services offered range from graphic design, to messages sung or spoken with various styles or accents, to complete apps for Android or iPhone. Skill providers on the platform can accept a range of variation of definition in the tasks, some can be described in general terms, for others it is more appropriate to provide examples. Fiverr provides a central location for those offering skills and those needing services to find each other, it makes it possible to communicate and exchange files, to make payments, and it provides support for resolving disputes. In all cases, it is important to keep expectations aligned with the nature of the platform: quality can and will vary. Ultimately, the critical contribution of Fiverr is not to replace professional services or otherwise save money, but rather to provide access to a large group of people with specialized skills who are able to make a contribution on short notice. In the context of this session, it can be considered a pool of people with MacGyver skills lying in wait of a MacGyyer task to attack. There are many ways in which Fiverr tasks, which are called 'gigs', can be useful in

  9. MacBook Teach Yourself VISUALLY

    CERN Document Server

    Miser, Brad

    2010-01-01

    Like the MacBook itself, Teach Yourself VISUALLY MacBook, Second Edition is designed to be visually appealing, while providing excellent functionality at the same time. By using this book, MacBook users will be empowered to do everyday tasks quickly and easily. From such basic steps as powering on or shutting down the MacBook, working on the Mac desktop with the Dashboard and its widgets to running Windows applications, Teach Yourself VISUALLY MacBook, Second Edition covers all the vital information and provides the help and support a reader needs—in many ways it's like having a Mac Genius at

  10. Increasing the quantity and quality of searching for current best evidence to answer clinical questions: protocol and intervention design of the MacPLUS FS Factorial Randomized Controlled Trials.

    Science.gov (United States)

    Agoritsas, Thomas; Iserman, Emma; Hobson, Nicholas; Cohen, Natasha; Cohen, Adam; Roshanov, Pavel S; Perez, Miguel; Cotoi, Chris; Parrish, Rick; Pullenayegum, Eleanor; Wilczynski, Nancy L; Iorio, Alfonso; Haynes, R Brian

    2014-09-20

    Finding current best evidence for clinical decisions remains challenging. With 3,000 new studies published every day, no single evidence-based resource provides all answers or is sufficiently updated. McMaster Premium LiteratUre Service--Federated Search (MacPLUS FS) addresses this issue by looking in multiple high quality resources simultaneously and displaying results in a one-page pyramid with the most clinically useful at the top. Yet, additional logistical and educational barriers need to be addressed to enhance point-of-care evidence retrieval. This trial seeks to test three innovative interventions, among clinicians registered to MacPLUS FS, to increase the quantity and quality of searching for current best evidence to answer clinical questions. In a user-centered approach, we designed three interventions embedded in MacPLUS FS: (A) a web-based Clinical Question Recorder; (B) an Evidence Retrieval Coach composed of eight short educational videos; (C) an Audit, Feedback and Gamification approach to evidence retrieval, based on the allocation of 'badges' and 'reputation scores.' We will conduct a randomized factorial controlled trial among all the 904 eligible medical doctors currently registered to MacPLUS FS at the hospitals affiliated with McMaster University, Canada. Postgraduate trainees (n=429) and clinical faculty/staff (n=475) will be randomized to each of the three following interventions in a factorial design (AxBxC). Utilization will be continuously recorded through clinicians’ accounts that track logins and usage, down to the level of individual keystrokes. The primary outcome is the rate of searches per month per user during the six months of follow-up. Secondary outcomes, measured through the validated Impact Assessment Method questionnaire, include: utility of answers found (meeting clinicians’ information needs), use (application in practice), and perceived usefulness on patient outcomes. Built on effective models for the point

  11. Performance analysis and improvement of WPAN MAC for home networks.

    Science.gov (United States)

    Mehta, Saurabh; Kwak, Kyung Sup

    2010-01-01

    The wireless personal area network (WPAN) is an emerging wireless technology for future short range indoor and outdoor communication applications. The IEEE 802.15.3 medium access control (MAC) is proposed to coordinate the access to the wireless medium among the competing devices, especially for short range and high data rate applications in home networks. In this paper we use analytical modeling to study the performance analysis of WPAN (IEEE 802.15.3) MAC in terms of throughput, efficient bandwidth utilization, and delay with various ACK policies under error channel condition. This allows us to introduce a K-Dly-ACK-AGG policy, payload size adjustment mechanism, and Improved Backoff algorithm to improve the performance of the WPAN MAC. Performance evaluation results demonstrate the impact of our improvements on network capacity. Moreover, these results can be very useful to WPAN application designers and protocol architects to easily and correctly implement WPAN for home networking.

  12. Performance Analysis and Improvement of WPAN MAC for Home Networks

    Directory of Open Access Journals (Sweden)

    Saurabh Mehta

    2010-03-01

    Full Text Available The wireless personal area network (WPAN is an emerging wireless technology for future short range indoor and outdoor communication applications. The IEEE 802.15.3 medium access control (MAC is proposed to coordinate the access to the wireless medium among the competing devices, especially for short range and high data rate applications in home networks. In this paper we use analytical modeling to study the performance analysis of WPAN (IEEE 802.15.3 MAC in terms of throughput, efficient bandwidth utilization, and delay with various ACK policies under error channel condition. This allows us to introduce a K-Dly-ACK-AGG policy, payload size adjustment mechanism, and Improved Backoff algorithm to improve the performance of the WPAN MAC. Performance evaluation results demonstrate the impact of our improvements on network capacity. Moreover, these results can be very useful to WPAN application designers and protocol architects to easily and correctly implement WPAN for home networking.

  13. Design and FPGA implementation for MAC layer of Ethernet PON

    Science.gov (United States)

    Zhu, Zengxi; Lin, Rujian; Chen, Jian; Ye, Jiajun; Chen, Xinqiao

    2004-04-01

    Ethernet passive optical network (EPON), which represents the convergence of low-cost, high-bandwidth and supporting multiple services, appears to be one of the best candidates for the next-generation access network. The work of standardizing EPON as a solution for access network is still underway in the IEEE802.3ah Ethernet in the first mile (EFM) task force. The final release is expected in 2004. Up to now, there has been no standard application specific integrated circuit (ASIC) chip available which fulfills the functions of media access control (MAC) layer of EPON. The MAC layer in EPON system has many functions, such as point-to-point emulation (P2PE), Ethernet MAC functionality, multi-point control protocol (MPCP), network operation, administration and maintenance (OAM) and link security. To implement those functions mentioned above, an embedded real-time operating system (RTOS) and a flexible programmable logic device (PLD) with an embedded processor are used. The software and hardware functions in MAC layer are realized through programming embedded microprocessor and field programmable gate array(FPGA). Finally, some experimental results are given in this paper. The method stated here can provide a valuable reference for developing EPON MAC layer ASIC.

  14. Mac OS X ja tietoturva

    OpenAIRE

    Herranen, Joni

    2011-01-01

    Tämän opinnäytetyön tavoitteena on luoda kattava kokonaiskuva Mac OS X -käyttöjärjestelmän sisäänrakennetuista tietoturvaratkaisuista ja selvittää miten tietoturvaratkaisut toteuttavat tietoturvan kolmea perustavoitetta eli luottamuksellisuutta, eheyttä ja saatavuutta. Työn kohderyhmäksi on valittu edistyneemmät tietokoneenkäyttäjät, joilla ei ole aikaisempaa Mac-kokemusta. Teoriaosuudessa syvennytään aluksi Apple-yhtiöön sekä Mac OS X -järjestelmän teknisiin ominaisuuksiin. Osuuden pääta...

  15. Mr MacDonald's suitcase

    DEFF Research Database (Denmark)

    2017-01-01

    Undervisningsforløbet Mr. MacDonald’s suitcase beskriver læringsmålstyret undervisning i faget engelsk i 1. klasse, hvor der arbejdes med kompetenceområdet mundtlig kommunikation. Undervisningsforløbet er bygget op omkring en engelsk tøjdukke, der besøger klassen og fortæller små historier...

  16. Mac OS X Lion Server For Dummies

    CERN Document Server

    Rizzo, John

    2011-01-01

    The perfect guide to help administrators set up Apple's Mac OS X Lion Server With the overwhelming popularity of the iPhone and iPad, more Macs are appearing in corporate settings. The newest version of Mac Server is the ideal way to administer a Mac network. This friendly guide explains to both Windows and Mac administrators how to set up and configure the server, including services such as iCal Server, Podcast Producer, Wiki Server, Spotlight Server, iChat Server, File Sharing, Mail Services, and support for iPhone and iPad. It explains how to secure, administer, and troubleshoot the networ

  17. Switching to the Mac The Missing Manual

    CERN Document Server

    Pogue, David

    2010-01-01

    Is Windows giving you pause? Ready to make the leap to the Mac instead? There has never been a better time to switch from Windows to Mac, and this incomparable guide will help you make a smooth transition. New York Times columnist and Missing Manuals creator David Pogue gets you past three challenges: transferring your stuff, assembling Mac programs so you can do what you did with Windows, and learning your way around Mac OS X. Learning to use a Mac is not a piece of cake, but once you do, the rewards are oh-so-much better. No viruses, worms, or spyware. No questionable firewalls, inefficien

  18. Switching to a Mac For Dummies

    CERN Document Server

    Reinhold, Arnold

    2007-01-01

    Thinking of making the switch from your PC to a Mac? Congratulations! You're in for a great, virus-free ride. And Switching to Mac For Dummies makes it smoother than you ever imagined. From buying the Mac that's right for you to transferring your files to breaking your old Windows habits and learning to do things the (much easier) Mac way, it makes the whole process practically effortless. Whether you've been using Windows XP, Vista, or even Linux, you'll find simple, straightforward ways to make your transition go smoothly. That will leave you plenty of time to get familiar with Mac'

  19. Mac OS X for Astronomy

    Science.gov (United States)

    Pierfederici, F.; Pirzkal, N.; Hook, R. N.

    Mac OS X is the new Unix based version of the Macintosh operating system. It combines a high performance DisplayPDF user interface with a standard BSD UNIX subsystem and provides users with simultaneous access to a broad range of applications which were not previously available on a single system such as Microsoft Office and Adobe Photoshop, as well as legacy X11-based scientific tools and packages like IRAF, SuperMongo, MIDAS, etc. The combination of a modern GUI layered on top of a familiar UNIX environment paves the way for new, more flexible and powerful astronomical tools to be developed while assuring compatibility with already existing, older programs. In this paper, we outline the strengths of the Mac OS X platform in a scientific environment, astronomy in particular, and point to the numerous astronomical software packages available for this platform; most notably the Scisoft collection which we have compiled.

  20. Technical Report : ContikiMAC vs X-MAC performance analysis

    OpenAIRE

    Michel, Mathieu; Quoitin, Bruno

    2014-01-01

    This paper try to better understand the performance of ContikiMAC compared to X-MAC. ContikiMAC achieves a transmission by repeatedly transmitting a data packet until the reception of an ACK from the destination. While X-MAC uses a stream of small size strobes to advertise the destination of the incoming transmission. A priori, X-MAC is then less bandwidth consumptive. To better understand the efficiency of ContikiMAC, despite an intuitively more consumptive transmitting procedure, we have co...

  1. Teach yourself visually Mac Mini

    CERN Document Server

    Hart-Davis, Guy

    2012-01-01

    The perfect how-to guide for visual learners Apple?s Mac Mini packs a powerful punch is in a small package, including both HDMI and Thunderbolt ports plus the acclaimed OS X. But if you want to get the very most from all this power and versatility, be sure to get this practical visual guide. With full-color, step-by-step instructions as well as screenshots and illustrations on every page, it clearly shows you how to accomplish tasks rather than burying you in pages of text. Discover helpful visuals and how-tos on the OS, hardware specs, Launchpad, the App Store, multimedia capabilities (such

  2. Web Development with the Mac

    CERN Document Server

    Vegh, Aaron

    2010-01-01

    Learn Web development the Apple way and build a business. With a focus on both coding and creative development, this in-depth guide thoroughly covers what you need to know to build winning websites for clients — from what it takes to bring a business online to how to make your site interactive to how to run a freelance web business. In between, you'll master the technical tools of the trade — such as HTML, CSS, JavaScript, PHP, and Ruby on Rails — and learn how to create beautiful interfaces using Photoshop . This book covers everything a fledgling web developer working on a Mac needs to launc

  3. Mac OS X Tiger for Unix Geeks

    CERN Document Server

    Jepson, Brian

    2005-01-01

    If you're one of the many Unix developers drawn to Mac OS X for its Unix core, you'll find yourself in surprisingly unfamiliar territory. Unix and Mac OS X are kissing cousins, but there are enough pitfalls and minefields in going from one to another that even a Unix guru can stumble, and most guides to Mac OS X are written for Mac aficionados. For a Unix developer, approaching Tiger from the Mac side is a bit like learning Russian by reading the Russian side of a Russian-English dictionary. Fortunately, O'Reilly has been the Unix authority for over 25 years, and in Mac OS X Tiger for Unix Gee

  4. Take control the Mac OS X lexicon

    CERN Document Server

    Zardetto, Sharon

    2009-01-01

    This ebook explains a little bit of everything; in fact, it's The Mac OS X (and then some) Lexicon because it's never just you and your Mac. It's you and your Mac and the Web, and your email, and that article you just read that threw 17 new acronyms at you or assumed that you knew all sorts of networking terms. Or it's you and your Mac and Finder features you've never touched, such as burn folders, smart folders, or proxy icons, and that mysterious Services submenu. This book is a great guide for Macintosh users everywhere who have trouble keeping up with the latest jargon, fo

  5. Macs all-in-one for dummies

    CERN Document Server

    Hutsko, Joe

    2014-01-01

    Your all-in-one guide to unleashing your Mac's full potential It's a Mac world out there. But if you haven't read the instruction manual, you may be neglecting some of your computer's coolest features. Turn to Macs All-in-One For Dummies' jam-packed guide to access the incredible tools within your computer. With this fully updated reference, you will learn how to use Launchpad and Mission Control; protect your Mac; back up and restore data with Time Machine; sync across devices in iCloud; import, organize, and share photos; direct in iMovie; compose in GarageBand; and so much more. The possi

  6. Douglas MacArthur Upon Reflection

    National Research Council Canada - National Science Library

    Snitchler, Lowell

    1998-01-01

    .... This research recounts MacArthur's personality development from childhood, investigates his last military campaign, and, finally, applies the diagnosis of narcissistic personality disorder to the assembled data...

  7. Quicksilver Power Mac G4

    CERN Document Server

    2001-01-01

    A new generation with a reworked motherboard is launched on 2001 with however the same Graphite box. It also included a processor speed-bump, and brought the DVD-R "SuperDrive" to the mid-level model. The Quicksilver PowerMac was available in three configurations: The 733 MHz model, with 128 MB of RAM, a 40 GB hard drive, and a CD-RW drive, was 1,699 dollars, the 867 MHz configuration, with 128 MB of RAM, a 60 GB hard drive and a DVD-R drive, was 2,499 dollars, and the high-end dual-800 MHz model, with 256 MB of RAM, an 80 GB hard drive and a DVD-R drive, was 3,499 dollars. The 733 MHz model is the first personal computer to have a DVD burner, named SuperDrive at Apple. The design was updated on 2002 with 800 MHz, 933 MHz and dual 1 GHz configurations, becoming the first Mac to reach 1 GHz.

  8. Behavioral Modeling of WSN MAC Layer Security Attacks: A Sequential UML Approach

    DEFF Research Database (Denmark)

    Pawar, Pranav M.; Nielsen, Rasmus Hjorth; Prasad, Neeli R.

    2012-01-01

    is the vulnerability to security attacks/threats. The performance and behavior of a WSN are vastly affected by such attacks. In order to be able to better address the vulnerabilities of WSNs in terms of security, it is important to understand the behavior of the attacks. This paper addresses the behavioral modeling...... of medium access control (MAC) security attacks in WSNs. The MAC layer is responsible for energy consumption, delay and channel utilization of the network and attacks on this layer can introduce significant degradation of the individual sensor nodes due to energy drain and in performance due to delays....... The behavioral modeling of attacks will be beneficial for designing efficient and secure MAC layer protocols. The security attacks are modeled using a sequential diagram approach of Unified Modeling Language (UML). Further, a new attack definition, specific to hybrid MAC mechanisms, is proposed....

  9. Analysis of 3gpp-MAC and two-key 3gpp-MAC

    DEFF Research Database (Denmark)

    Knudsen, Lars Ramkilde; Mitchell, C.J.

    2003-01-01

    Forgery and key-recovery attacks are described on the 3gpp-MAC scheme, proposed for inclusion in the 3gpp specification. Three main classes of attack are given, all of which operate whether or not truncation is applied to the MAC value. Attacks in the first class use a large number of 'chosen MAC...

  10. George MacDonald's Estimate of Childhood

    Science.gov (United States)

    Pridmore, John

    2007-01-01

    The nineteenth-century fantasy writer George MacDonald believed that "it is better to be a child in a green field than a knight of many orders." In this paper, I shall explore the bearing of this high estimate of childhood on spiritual education. MacDonald explores the spirituality of the child in his essay "A Sketch of Individual Development" and…

  11. ETEEM- Extended Traffic Aware Energy Efficient MAC Scheme for WSNs

    OpenAIRE

    Younas Khan; Sheeraz Ahmed; Fakhri Alam Khan; Imran Ahmad; Saqib Shahid Rahim; M. Irfan Khattak

    2016-01-01

    Idle listening issue arises when a sensor node listens to medium despite the absence of data which results in consumption of energy. ETEEM is a variant of Traffic Aware Energy Efficient MAC protocol (TEEM) which focuses on energy optimization due to reduced idle listening time and much lesser overhead on energy sources. It uses a novel scheme for using idle listening time of sensor nodes. The nodes are only active for small amount of time and most of the time, will be in sleep mode when no da...

  12. High-throughput and low-latency 60GHz small-cell network architectures over radio-over-fiber technologies

    Science.gov (United States)

    Pleros, N.; Kalfas, G.; Mitsolidou, C.; Vagionas, C.; Tsiokos, D.; Miliou, A.

    2017-01-01

    Future broadband access networks in the 5G framework will need to be bilateral, exploiting both optical and wireless technologies. This paper deals with new approaches and synergies on radio-over-fiber (RoF) technologies and how those can be leveraged to seamlessly converge wireless technology for agility and mobility with passive optical networks (PON)-based backhauling. The proposed convergence paradigm is based upon a holistic network architecture mixing mm-wave wireless access with photonic integration, dynamic capacity allocation and network coding schemes to enable high bandwidth and low-latency fixed and 60GHz wireless personal area communications for gigabit rate per user, proposing and deploying on top a Medium-Transparent MAC (MT-MAC) protocol as a low-latency bandwidth allocation mechanism. We have evaluated alternative network topologies between the central office (CO) and the access point module (APM) for data rates up to 2.5 Gb/s and SC frequencies up to 60 GHz. Optical network coding is demonstrated for SCM-based signaling to enhance bandwidth utilization and facilitate optical-wireless convergence in 5G applications, reporting medium-transparent network coding directly at the physical layer between end-users communicating over a RoF infrastructure. Towards equipping the physical layer with the appropriate agility to support MT-MAC protocols, a monolithic InP-based Remote Antenna Unit optoelectronic PIC interface is shown that ensures control over the optical resource allocation assisting at the same time broadband wireless service. Finally, the MT-MAC protocol is analysed and simulation and analytical theoretical results are presented that are found to be in good agreement confirming latency values lower than 1msec for small- to mid-load conditions.

  13. Energy-efficient TDMA medium access control protocol scheduling

    NARCIS (Netherlands)

    Havinga, Paul J.M.; Smit, Gerard J.M.

    2000-01-01

    In this paper we study the energy efficiency and channel efficiency of TDMA MAC protocol scheduling mechanisms. Most MAC protocols are based on phase grouping that basically has three phases in a frame: uplink, downlink and reservation. We propose a new mechanism in which we have multiple uplink and

  14. Detomidine reduces isoflurane anesthetic requirement (MAC) in horses.

    Science.gov (United States)

    Steffey, Eugene P; Pascoe, Peter J

    2002-10-01

    To quantitate the dose- and time-related magnitude of the anesthetic sparing effect of, and selected physiological responses to detomidine during isoflurane anesthesia in horses. Randomized cross-over study. Three, healthy, young adult horses weighing 485 ± 14 kg. Horses were anesthetized on two occasions to determine the minimum alveolar concentration (MAC) of isoflurane in O 2 and then to measure the anesthetic sparing effect (time-related MAC reduction) following IV detomidine (0.03 and 0.06 mg kg -1 ). Selected common measures of cardiopulmonary function, blood glucose and urinary output were also recorded. Isoflurane MAC was 1.44 ± 0.07% (mean ± SEM). This was reduced by 42.8 ± 5.4% and 44.8 ± 3.0% at 83 ± 23 and 125 ± 36 minutes, respectively, following 0.03 and 0.06 mg kg -1 , detomidine. The MAC reduction was detomidine dose- and time-dependent. There was a tendency for mild cardiovascular and respiratory depression, especially following the higher detomidine dose. Detomidine increased both blood glucose and urine flow; the magnitude of these changes was time- and dose-dependent CONCLUSIONS: Detomidine reduces anesthetic requirement for isoflurane and increases blood glucose concentration and urine flow in horses. These changes were dose- and time-related. The results imply potent anesthetic sparing actions by detomidine. The detomidine-related increased urine flow should be considered in designing anesthetic protocols for individual horses. Copyright © 2002 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.

  15. TMAC: Timestamp-Ordered MAC for CSMA/CA Wireless Mesh Networks

    KAUST Repository

    Nawab, Faisal Saud Yousef; Jamshaid, Kamran; Shihada, Basem; Ho, Pin-Han

    2011-01-01

    We propose TMAC, a timestamp-ordered MAC protocol for Wireless Mesh Networks (WMNs). TMAC extends CSMA/CA by scheduling data packets based on their age. Prior to transmitting a data packet, a transmitter broadcasts a request control message appended

  16. Radio astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Nagnibeda, V.G.

    1981-01-01

    The history of radio astronomical observations at the Astronomical Observatory of Leningrad State University is reviewed. Various facilities are described, and methods and instruments used are discussed. Some results are summarized for radio observations of the sun, including observations of local sources of solar radio emission, the absolute solar radio flux, and radio emission from filaments and prominences.

  17. Mac OS X for Unix Geeks (Leopard)

    CERN Document Server

    Rothman, Ernest E; Rosen, Rich

    2009-01-01

    If you've been lured to Mac OS X because of its Unix roots, this invaluable book serves as a bridge between Apple's Darwin OS and the more traditional Unix systems. The new edition offers a complete tour of Mac OS X's Unix shell for Leopard and Tiger, and helps you find the facilities that replace or correspond to standard Unix utilities. Learn how to compile code, link to libraries, and port Unix software to Mac OS X and much more with this concise guide.

  18. Office 2008 for Mac for dummies

    CERN Document Server

    LeVitus, Bob

    2013-01-01

    Office 2008 for Mac is here, with great new enhancements to all your favorite office productivity tools. Who better than "Dr. Mac, "Bob LeVitus, to show you how to load and use them all? From choosing the best version for your needs to managing your life with your online calendar, Office 2008 For Mac For Dummies covers what you need to know. It compares the Student/Teacher Edition, Standard Edition, and Professional Edition, then walks you through installing your preferred version and keeping it up to date. You'll find out all the things you can do with Word, Excel, PowerPoint, and Entourage,

  19. Learn Office 2011 for Mac OS X

    CERN Document Server

    Hart-Davis, Guy

    2011-01-01

    Office for Mac remains the leading productivity suite for Mac, with Apple's iWork and the free OpenOffice.org trailing far behind. And now it's being updated with a cleaner interface and more compatibility with Exchange and SharePoint. Learn Office 2011 for Mac OS X offers a practical, hands-on approach to using Office 2011 applications to create and edit documents and get work done efficiently. You'll learn how to customize Office, design, create, and share documents, manipulate data in a spreadsheet, and create lively presentations. You'll also discover how to organize your email, contacts,

  20. Is Kyoto Fatally Flawed? An Analysis with MacGEM

    International Nuclear Information System (INIS)

    Eyckmans, J.; Van Regemorter, D.; Van Steenberghe, V.

    2002-06-01

    In this paper we present some numerical simulations with the MacGEM model to evaluate the consequences of the recent Marrakesh agreements and the defection of the USA for the Kyoto Protocol. MacGEM is a global marginal abatement cost model for carbon emissions from fossil fuel use based on the GEM-E3-World general equilibrium. Nonparticipation of the USA causes the equilibrium carbon price in Annex B countries to fall by approximately 50% since an important share of permit demand falls out. Carbon sinks enhancement activities enable Parties to fulfil their reduction commitment at lower compliance costs and cause the equilibrium permit price to decrease by 40%. Finally, it is shown that the former Soviet Union and central European countries have substantial monopoly power in the Kyoto carbon permit market. We conclude that the recent accords have eroded completely the Kyoto Protocol's emission targets but that they have the merit to have saved the international climate change negotiation framework

  1. MACS as a tool for international inspections

    International Nuclear Information System (INIS)

    Curtiss, J.A.; Indusi, J.P.

    1995-01-01

    The MACS/ACRS (Managed Access by Controlled Sensing/Access by Controlled Remote Sensing) system is a collection of communication devices, video capability, and distance-measuring equipment which can effectively substitute for the physical presence of a challenge inspector within a facility. The MACS design allows growth of the prototype, developed in response to the Chemical Weapons Convention (CWC), into a versatile device for inspection of sensitive nuclear facilities under other international arrangements, for example the proposed Fissile Material Cutoff Convention. A MACS/ACRS-type system in a standard, international-recognized configuration could resolve sensitive information and safety concerns through providing a means of achieving the goals of an inspection while excluding the inspector. We believe the technology used to develop MACS for the Defense Nuclear Agency, followed by ACRS for the Department of Energy, is universally adaptable for minimally-intrusive managed-access international inspections of sensitive sites

  2. MACS as a tool for international inspections

    Energy Technology Data Exchange (ETDEWEB)

    Curtiss, J.A.; Indusi, J.P.

    1995-08-01

    The MACS/ACRS (Managed Access by Controlled Sensing/Access by Controlled Remote Sensing) system is a collection of communication devices, video capability, and distance-measuring equipment which can effectively substitute for the physical presence of a challenge inspector within a facility. The MACS design allows growth of the prototype, developed in response to the Chemical Weapons Convention (CWC), into a versatile device for inspection of sensitive nuclear facilities under other international arrangements, for example the proposed Fissile Material Cutoff Convention. A MACS/ACRS-type system in a standard, international-recognized configuration could resolve sensitive information and safety concerns through providing a means of achieving the goals of an inspection while excluding the inspector. We believe the technology used to develop MACS for the Defense Nuclear Agency, followed by ACRS for the Department of Energy, is universally adaptable for minimally-intrusive managed-access international inspections of sensitive sites.

  3. Learn Mac OS X Snow Leopard

    CERN Document Server

    Meyers, Scott

    2009-01-01

    You're smart and savvy, but also busy. This comprehensive guide to Apple's Mac OS X 10.6, Snow Leopard, gives you everything you need to know to live a happy, productive Mac life. Learn Mac OS X Snow Leopard will have you up and connected lickity split. With a minimum of overhead and a maximum of useful information, you'll cover a lot of ground in the time it takes other books to get you plugged in. If this isn't your first experience with Mac OS X, skip right to the "What's New in Snow Leopard" sections. You may also find yourself using this book as a quick refresher course or a way

  4. MAC reduction of isoflurane by sufentanil.

    Science.gov (United States)

    Brunner, M D; Braithwaite, P; Jhaveri, R; McEwan, A I; Goodman, D K; Smith, L R; Glass, P S

    1994-01-01

    We have shown previously that a plasma fentanyl concentration of 1.67 ng ml-1 reduced the MAC of isoflurane by 50%. By comparing equal degrees of MAC reduction by sufentanil, we may determine the potency ratio of these opioids. Seventy-six patients were allocated randomly to receive predetermined infusions of sufentanil, and end-tidal concentrations of isoflurane in oxygen. Blood samples were obtained 10 min after the start of the infusion, and just before and after skin incision. Any purposeful movement by the patient was recorded. The MAC reduction of isoflurane produced by sufentanil was obtained using a logistic regression model. A sufentanil plasma concentration of 0.145 ng ml-1 (95% confidence limits 0.04, 0.26 ng ml-1) resulted in a 50% reduction in the MAC of isoflurane. At a plasma concentration greater than 0.5 ng ml-1, sufentanil exhibited a ceiling effect.

  5. Macintosh Troubleshooting Pocket Guide for Mac OS

    CERN Document Server

    Lerner, David; Corporation, Tekserve

    2009-01-01

    The Macintosh Troubleshooting Pocket Guide covers the most common user hardware and software trouble. It's not just a book for Mac OS X (although it includes tips for OS X and Jaguar), it's for anyone who owns a Mac of any type-- there are software tips going back as far as OS 6. This slim guide distills the answers to the urgent questions that Tekserve's employee's answer every week into a handy guide that fits in your back pocket or alongside your keyboard.

  6. Enhanced Sleep Mode MAC Control for EPON

    DEFF Research Database (Denmark)

    Yan, Ying; Dittmann, Lars

    2011-01-01

    This paper introduces sleep mode operations for EPON. New MAC control functions are proposed to schedule sleep periods. Traffic profiles are considered to optimize energy efficiency and network performances. Simulation results are analyzed in OPNET modeler.......This paper introduces sleep mode operations for EPON. New MAC control functions are proposed to schedule sleep periods. Traffic profiles are considered to optimize energy efficiency and network performances. Simulation results are analyzed in OPNET modeler....

  7. Wound Healing in Mac-1 Deficient Mice

    Science.gov (United States)

    2017-05-01

    Dentistry, University of Illinois at Chicago, Chicago, IL, USA. 2 Department of Defense Biotechnology High Performance Computing Software...study, we used a commercially available Mac-1 deficient strain to examine whether this deficit 5 extends to slightly smaller wounds and incisional...levels of Collagen I and Collagen III in wounds from the two strains of mice at any time point. Unwounded skin from both WT and Mac-1 -/- mice contained

  8. AeroMACS system characterization and demonstrations

    Science.gov (United States)

    Kerczewski, R. J.; Apaza, R. D.; Dimond, R. P.

    This The Aeronautical Mobile Airport Communications System (AeroMACS) is being developed to provide a new broadband wireless communications capability for safety critical communications in the airport surface domain, providing connectivity to aircraft and other ground vehicles as well as connections between other critical airport fixed assets. AeroMACS development has progressed from requirements definition through technology definition, prototype deployment and testing, and now into national and international standards development. The first prototype AeroMACS system has been deployed at the Cleveland Hopkins International Airport (CLE) and the adjacent NASA Glenn Research Center (GRC). During the past three years, extensive technical testing has taken place to characterize the performance of the AeroMACS prototype and provide technical support for the standards development process. The testing has characterized AeroMACS link and network performance over a variety of conditions for both fixed and mobile data transmission and has included basic system performance testing and fixed and mobile applications testing. This paper provides a summary of the AeroMACS performance testing and the status of standardization activities that the testing supports.

  9. Chandra and JVLA Observations of HST Frontier Fields Cluster MACS J0717.5+3745

    International Nuclear Information System (INIS)

    Van Weeren, R. J.; Jones, C.; Forman, W. R.; Andrade-Santos, F.; Pearce, Connor J. J.; David, L.; Kraft, R. P.; Nulsen, P. E. J.; Ogrean, G. A.; Bonafede, A.; Brüggen, M.; Bulbul, E.; Clarke, T. E.; Churazov, E.; Dawson, W. A.; Donahue, M.; Goulding, A.; Mason, B.; Merten, J.; Mroczkowski, T.

    2017-01-01

    To investigate the relationship between thermal and non-thermal components in merger galaxy clusters, we present deep JVLA and Chandra observations of the HST Frontier Fields cluster MACS J0717.5+3745. The Chandra image shows a complex merger event, with at least four components belonging to different merging subclusters. Northwest of the cluster, ∼0.7 Mpc from the center, there is a ram-pressure-stripped core that appears to have traversed the densest parts of the cluster after entering the intracluster medium (ICM) from the direction of a galaxy filament to the southeast. We detect a density discontinuity north-northeast of this core, which we speculate is associated with a cold front. Our radio images reveal new details for the complex radio relic and radio halo in this cluster. In addition, we discover several new filamentary radio sources with sizes of 100–300 kpc. A few of these seem to be connected to the main radio relic, while others are either embedded within the radio halo or projected onto it. A narrow-angled-tailed (NAT) radio galaxy, a cluster member, is located at the center of the radio relic. The steep spectrum tails of this active galactic nucleus lead into the large radio relic where the radio spectrum flattens again. This morphological connection between the NAT radio galaxy and relic provides evidence for re-acceleration (revival) of fossil electrons. The presence of hot ≳20 keV ICM gas detected by Chandra near the relic location provides additional support for this re-acceleration scenario.

  10. Chandra and JVLA Observations of HST Frontier Fields Cluster MACS J0717.5+3745

    Energy Technology Data Exchange (ETDEWEB)

    Van Weeren, R. J.; Jones, C.; Forman, W. R.; Andrade-Santos, F.; Pearce, Connor J. J.; David, L.; Kraft, R. P.; Nulsen, P. E. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ogrean, G. A. [Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305-4060 (United States); Bonafede, A.; Brüggen, M. [Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, D-21029 Hamburg (Germany); Bulbul, E. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Clarke, T. E. [U.S. Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375 (United States); Churazov, E. [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85741, Garching (Germany); Dawson, W. A. [Lawrence Livermore National Lab, 7000 East Avenue, Livermore, CA 94550 (United States); Donahue, M. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Goulding, A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Mason, B. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Merten, J. [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Mroczkowski, T., E-mail: rvanweeren@cfa.harvard.edu [ESO—European Organization for Astronomical Research in the Southern Hemisphere, Karl-Schwarzschild-Str. 2, D-85748 Garching b. München (Germany); and others

    2017-02-01

    To investigate the relationship between thermal and non-thermal components in merger galaxy clusters, we present deep JVLA and Chandra observations of the HST Frontier Fields cluster MACS J0717.5+3745. The Chandra image shows a complex merger event, with at least four components belonging to different merging subclusters. Northwest of the cluster, ∼0.7 Mpc from the center, there is a ram-pressure-stripped core that appears to have traversed the densest parts of the cluster after entering the intracluster medium (ICM) from the direction of a galaxy filament to the southeast. We detect a density discontinuity north-northeast of this core, which we speculate is associated with a cold front. Our radio images reveal new details for the complex radio relic and radio halo in this cluster. In addition, we discover several new filamentary radio sources with sizes of 100–300 kpc. A few of these seem to be connected to the main radio relic, while others are either embedded within the radio halo or projected onto it. A narrow-angled-tailed (NAT) radio galaxy, a cluster member, is located at the center of the radio relic. The steep spectrum tails of this active galactic nucleus lead into the large radio relic where the radio spectrum flattens again. This morphological connection between the NAT radio galaxy and relic provides evidence for re-acceleration (revival) of fossil electrons. The presence of hot ≳20 keV ICM gas detected by Chandra near the relic location provides additional support for this re-acceleration scenario.

  11. MacSelfService online tutorial

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    Mac Self-Service is a functionality within the Mac Desktop Service built and maintained to empower CERN users by giving them easy access to applications and configurations through the Self-Service application. This tutorial (text attached to the event page) explains how to install Mac Self-Service and how to use it to install applications and printers. Content owner: Vincent Nicolas Bippus Presenter: Pedro Augusto de Freitas Batista Tell us what you think via e-learning.support at cern.ch More tutorials in the e-learning collection of the CERN Document Server (CDS) https://cds.cern.ch/collection/E-learning%20modules?ln=en All info about the CERN rapid e-learning project is linked from http://twiki.cern.ch/ELearning  

  12. MacBook Pro Portable Genius

    CERN Document Server

    Miser, Brad

    2011-01-01

    Tips and techniques for forward-thinking MacBook Pro users Now that you have a MacBook Pro, you need just one more accessory, your very own copy of MacBook Pro Portable Genius, Third Edition. This handy, compact book lets you in on a wealth of tips and tricks, so you get the very most out of Apple's very popular notebook. Discover the latest on the most recent release of iLife, get the skinny on the new Intel Core i7 and i5 processors in the Pro, see how to go wireless in a smart way, and much more. The book is easy to navigate, doesn't skimp on the essentials, and helps you save time and avoi

  13. A MAC Mode for Lightweight Block Ciphers

    DEFF Research Database (Denmark)

    Luykx, Atul; Preneel, Bart; Tischhauser, Elmar Wolfgang

    2016-01-01

    Lightweight cryptography strives to protect communication in constrained environments without sacrificing security. However, security often conflicts with efficiency, shown by the fact that many new lightweight block cipher designs have block sizes as low as 64 or 32 bits. Such low block sizes lead...... no effect on the security bound, allowing an order of magnitude more data to be processed per key. Furthermore, LightMAC is incredibly simple, has almost no overhead over the block cipher, and is parallelizable. As a result, LightMAC not only offers compact authentication for resource-constrained platforms...

  14. Douglas MacArthur- An Administrative Biography

    OpenAIRE

    Tehan III, William J.

    2002-01-01

    For more than a half century Douglas MacArthur was a servant of the United States. He is best remembered as a general and a soldier, especially for his leadership during World War II and the Korean War. MacArthur was also the Superintendent of West Point, Chief of Staff of the U.S. Army, Generalissimo ( Commander) of the Armed Forces and Military Advisor (Minister of Defense) to the President of the Commonwealth of the Philippines, and the Supreme Commander Allied Powers and the Military Gove...

  15. MacBook Pro Portable Genius

    CERN Document Server

    Miser, Brad

    2012-01-01

    Discover loads of tips and techniques for the newest MacBook Pro You're already ahead of the game with a MacBook Pro. Now you can get even more out the popular Apple notebook with the new edition of this handy, compact book. Crammed with savvy insights and tips on key tools and shortcuts, this book will help you increase your productivity and keep your Apple digital lifestyle on track. From desktop sharing and wireless networking to running Windows applications, this book avoids fluff, doesn't skimp on the essentials, saves you time and hassle, and shows you what you most want to know. Include

  16. Mac OS X Snow Leopard pocket guide

    CERN Document Server

    Seiblod, Chris

    2009-01-01

    Whether you're new to the Mac or a longtime user, this handy book is the quickest way to get up to speed on Snow Leopard. Packed with concise information in an easy-to-read format, Mac OS X Snow Leopard Pocket Guide covers what you need to know and is an ideal resource for problem-solving on the fly. This book goes right to the heart of Snow Leopard, with details on system preferences, built-in applications, and utilities. You'll also find configuration tips, keyboard shortcuts, guides for troubleshooting, lots of step-by-step instructions, and more. Learn about new features and changes s

  17. Radio stars

    International Nuclear Information System (INIS)

    Hjellming, R.M.

    1976-01-01

    Any discussion of the radio emission from stars should begin by emphasizing certain unique problems. First of all, one must clarify a semantic confusion introduced into radio astronomy in the late 1950's when most new radio sources were described as radio stars. All of these early 'radio stars' were eventually identified with other galactic and extra-galactic objects. The study of true radio stars, where the radio emission is produced in the atmosphere of a star, began only in the 1960's. Most of the work on the subject has, in fact, been carried out in only the last few years. Because the real information about radio stars is quite new, it is not surprising that major aspects of the subject are not at all understood. For this reason this paper is organized mainly around three questions: what is the available observational information; what physical processes seem to be involved; and what working hypotheses look potentially fruitful. (Auth.)

  18. Results from the MAC Vertex chamber

    International Nuclear Information System (INIS)

    Nelson, H.N.

    1987-05-01

    The design, construction, and performance characteristics of a high precision gaseous drift chamber made of thin walled proportional tubes are described. The device achieved an average spatial resolution of 45 μm in use for physics analysis with the MAC detector. The B-lifetime result obtained with this chamber is discussed

  19. The Big Mac Standard: A statistical Illustration

    OpenAIRE

    Yukinobu Kitamura; Hiroshi Fujiki

    2004-01-01

    We demonstrate a statistical procedure for selecting the most suitable empirical model to test an economic theory, using the example of the test for purchasing power parity based on the Big Mac Index. Our results show that supporting evidence for purchasing power parity, conditional on the Balassa-Samuelson effect, depends crucially on the selection of models, sample periods and economies used for estimations.

  20. MacIntyre, Managerialism and Universities

    Science.gov (United States)

    Stolz, Steven A.

    2017-01-01

    MacIntyre's earlier work and concern with social science enquiry not only exposes its limits, but also provides an insight into how its knowledge claims have been put to ideological use. He maintains that the institutional embodiment of these ideological ideas is the bureaucratic manager who has had a negative role to play in social structures…

  1. Florence Jessie Mac Williams (1917-1990)

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 1. Florence Jessie Mac Williams (1917-1990). Featured Scientist Volume 10 Issue 1 January 2005 pp 98-98. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/010/01/0098-0098. Resonance ...

  2. An Interview with Peter MacDonald.

    Science.gov (United States)

    American Indian Journal, 1979

    1979-01-01

    Peter MacDonald, Chairman of the Navajo Nation, the largest tribe in the United States speaks to such issues as energy development/management, oil companies, Navajo-Hopi relocation legislation, traditionalism, and the role of the Council of Energy Resource Tribes. (RTS)

  3. Lifetime tests for MAC vertex chamber

    International Nuclear Information System (INIS)

    Nelson, H.N.

    1986-07-01

    A vertex chamber for MAC was proposed to increase precision in the measurement of the B hadron and tau lepton lifetimes. Thin-walled aluminized mylar drift tubes were used for detector elements. A study of radiation hardness was conducted under the conditions of the proposed design using different gases and different operating conditions

  4. MACS as a tool for international inspections

    International Nuclear Information System (INIS)

    Curtiss, J.A.; Indusi, J.P.

    1995-01-01

    General acceptance of the challenge provision in the Chemical Weapons Convention has the potential for influence in other arms control areas. While most applications of the challenge inspection may be straightforward, there may be instances where access to the site by inspectors may be problematic. The MACS system described in this paper was developed to respond to these situations. Inspection and verification may be difficult when a host is unwilling,for valid reasons, to permit physical access to a site. We proposed a system of remote sensors which may be used to demonstrate compliance with Chemical Weapons Convention (CWC) challenge inspections even ff the inspector is physically excluded from a sensitive site. The system is based upon alternative-means-of-access provisions of the CWC. The Defense Nuclear Agency (DNA) funded design and construction of a system prototype, designated as MACS for Managed Access by Controlled Sensing. Features of the MACS design allow growth of the prototype into a versatile device for international monitoring of production facilities and other sites. MACS consists of instrumentation and communication equipment allowing site personnel to conduct a facility tour and perform acceptable measurements, while physically excluding the inspector from the facility. MACS consists of a base station used by the inspector, and a mobile unit used within the facility and manipulated by the facility staff. The base station and the mobile unit are at sign ed by a communication system, currently realized as a fiber optic cable. The mobile unit is equipped with television cameras and remote-reading distance-measuring equipment (DME) for use in verifying locations and dimensions. Global Positioning System receivers on the mobile unit provide both precise location and dead reckoning, suitable for tracking the mobile unit's position while within a building when satellite signals are not available

  5. Mammalian Synthetic Biology: Time for Big MACs.

    Science.gov (United States)

    Martella, Andrea; Pollard, Steven M; Dai, Junbiao; Cai, Yizhi

    2016-10-21

    The enabling technologies of synthetic biology are opening up new opportunities for engineering and enhancement of mammalian cells. This will stimulate diverse applications in many life science sectors such as regenerative medicine, development of biosensing cell lines, therapeutic protein production, and generation of new synthetic genetic regulatory circuits. Harnessing the full potential of these new engineering-based approaches requires the design and assembly of large DNA constructs-potentially up to chromosome scale-and the effective delivery of these large DNA payloads to the host cell. Random integration of large transgenes, encoding therapeutic proteins or genetic circuits into host chromosomes, has several drawbacks such as risks of insertional mutagenesis, lack of control over transgene copy-number and position-specific effects; these can compromise the intended functioning of genetic circuits. The development of a system orthogonal to the endogenous genome is therefore beneficial. Mammalian artificial chromosomes (MACs) are functional, add-on chromosomal elements, which behave as normal chromosomes-being replicating and portioned to daughter cells at each cell division. They are deployed as useful gene expression vectors as they remain independent from the host genome. MACs are maintained as a single-copy and can accommodate multiple gene expression cassettes of, in theory, unlimited DNA size (MACs up to 10 megabases have been constructed). MACs therefore enabled control over ectopic gene expression and represent an excellent platform to rapidly prototype and characterize novel synthetic gene circuits without recourse to engineering the host genome. This review describes the obstacles synthetic biologists face when working with mammalian systems and how the development of improved MACs can overcome these-particularly given the spectacular advances in DNA synthesis and assembly that are fuelling this research area.

  6. Strategies for Optimal MAC Parameters Tuning in IEEE 802.15.6 Wearable Wireless Sensor Networks.

    Science.gov (United States)

    Alam, Muhammad Mahtab; Ben Hamida, Elyes

    2015-09-01

    Wireless body area networks (WBAN) has penetrated immensely in revolutionizing the classical heath-care system. Recently, number of WBAN applications has emerged which introduce potential limits to existing solutions. In particular, IEEE 802.15.6 standard has provided great flexibility, provisions and capabilities to deal emerging applications. In this paper, we investigate the application-specific throughput analysis by fine-tuning the physical (PHY) and medium access control (MAC) parameters of the IEEE 802.15.6 standard. Based on PHY characterizations in narrow band, at the MAC layer, carrier sense multiple access collision avoidance (CSMA/CA) and scheduled access protocols are extensively analyzed. It is concluded that, IEEE 802.15.6 standard can satisfy most of the WBANs applications throughput requirements by maximum achieving 680 Kbps. However, those emerging applications which require high quality audio or video transmissions, standard is not able to meet their constraints. Moreover, delay, energy efficiency and successful packet reception are considered as key performance metrics for comparing the MAC protocols. CSMA/CA protocol provides the best results to meet the delay constraints of medical and non-medical WBAN applications. Whereas, the scheduled access approach, performs very well both in energy efficiency and packet reception ratio.

  7. Wake-up radio systems : design, development, performance evaluation and comparison to conventional medium access control protocols for wireless sensor networks

    OpenAIRE

    Oller i Bosch, Joaquim

    2015-01-01

    During the recent years, the research related to Wake-up Radio (WuR) systems has gained noticeable interest. In WuR systems, a node initiating a communication first sends a Wake-up Call (WuC) by means of its Wake-up Transmitter (WuTx), to the Wake-up Receiver (WuRx) of a remote node to activate it in an on-demand manner. Until the reception of the WuC, the node's MCU and main data transceiver are in sleep mode. Hence, WuR drastically reduce the power required by wireless nodes. This thesis...

  8. The periplasmic membrane proximal domain of MacA acts as a switch in stimulation of ATP hydrolysis by MacB transporter.

    Science.gov (United States)

    Modali, Sita D; Zgurskaya, Helen I

    2011-08-01

    Escherichia coli MacAB-TolC is a tripartite macrolide efflux transporter driven by hydrolysis of ATP. In this complex, MacA is the periplasmic membrane fusion protein that stimulates the activity of MacB transporter and establishes the link with the outer membrane channel TolC. The molecular mechanism by which MacA stimulates MacB remains unknown. Here, we report that the periplasmic membrane proximal domain of MacA plays a critical role in functional MacA-MacB interactions and stimulation of MacB ATPase activity. Binding of MacA to MacB stabilizes the ATP-bound conformation of MacB, whereas interactions with both MacB and TolC affect the conformation of MacA. A single G353A substitution in the C-terminus of MacA inactivates MacAB-TolC function by changing the conformation of the membrane proximal domain of MacA and disrupting the proper assembly of the MacA-MacB complex. We propose that MacA acts in transport by promoting MacB transition into the closed ATP-bound conformation and in this respect, is similar to the periplasmic solute-binding proteins. © 2011 Blackwell Publishing Ltd.

  9. MAC-Level Communication Time Modeling and Analysis for Real-Time WSNs

    Directory of Open Access Journals (Sweden)

    STANGACIU, V.

    2016-02-01

    Full Text Available Low-level communication protocols and their timing behavior are essential to developing wireless sensor networks (WSNs able to provide the support and operating guarantees required by many current real-time applications. Nevertheless, this aspect still remains an issue in the state-of-the-art. In this paper we provide a detailed analysis of a recently proposed MAC-level communication timing model and demonstrate its usability in designing real-time protocols. The results of a large set of measurements are also presented and discussed here, in direct relation to the main time parameters of the analyzed model.

  10. Radio stars

    International Nuclear Information System (INIS)

    Hjellming, R.M.; Gibson, D.M.

    1985-01-01

    Studies of stellar radio emission became an important field of research in the 1970's and have now expanded to become a major area of radio astronomy with the advent of new instruments such as the Very Large Array in New Mexico and transcontinental telescope arrays. This volume contains papers from the workshop on stellar continuum radio astronomy held in Boulder, Colorado, and is the first book on the rapidly expanding field of radio emission from stars and stellar systems. Subjects covered include the observational and theoretical aspects of stellar winds from both hot and cool stars, radio flares from active double star systems and red dwarf stars, bipolar flows from star-forming regions, and the radio emission from X-ray binaries. (orig.)

  11. MacBook All-in-One For Dummies

    CERN Document Server

    Chambers, Mark L

    2011-01-01

    Get comfortable and confident with your MacBook! Combining the fun-but-straightforward content of nine minibooks, this new edition of MacBook All-in-One For Dummies delivers helpful coverage of the rich features and essential tools you need to know to use the MacBook to its fullest potential. You'll learn an array of MacBook basics while veteran author Mark Chambers walks you through setting up your MacBook, running programs, finding files with Finder, searching with Spotlight, keeping track with Address Book, enjoying music with iTunes, creating cool multimedia projects with iLife, and more.

  12. MacBook Pro portable genius

    CERN Document Server

    Gruman, Galen

    2013-01-01

    Learn the skills, tools and shortcuts you need in order to make the most of your MacBook Pro This easy-to-use, compact guide skips the fluff and gets right to the essentials so that you can maximize all the latest features of the MacBook Pro. Packed with savvy insights and tips on key tools and shortcuts, this handy book aims to help you increase your productivity and save you time and hassle. From desktop sharing and wireless networking to running Windows applications and more, this book shows you what you want to know. Includes the latest version of OS X, iCloud, FaceTime, and moreCovers al

  13. Millisecond timing on PCs and Macs.

    Science.gov (United States)

    MacInnes, W J; Taylor, T L

    2001-05-01

    A real-time, object-oriented solution for displaying stimuli on Windows 95/98, MacOS and Linux platforms is presented. The program, written in C++, utilizes a special-purpose window class (GLWindow), OpenGL, and 32-bit graphics acceleration; it avoids display timing uncertainty by substituting the new window class for the default window code for each system. We report the outcome of tests for real-time capability across PC and Mac platforms running a variety of operating systems. The test program, which can be used as a shell for programming real-time experiments and testing specific processors, is available at http://www.cs.dal.ca/~macinnwj. We propose to provide researchers with a sense of the usefulness of our program, highlight the ability of many multitasking environments to achieve real time, as well as caution users about systems that may not achieve real time, even under optimal conditions.

  14. Improved b lifetime measurement from MAC

    International Nuclear Information System (INIS)

    Ford, W.T.

    1984-03-01

    Two recent publications, from the MAC and Mark II collaborations, have reported the somewhat surprising result that the lifetime of particles made up of b quarks is in the 1 to 2 picosecond range, or somewhat longer than the lifetimes of charm particles. Although the charm decays are favored transitions while those of b particles depend upon off-diagonal elements of the weak flavor mixing matrix, the smallness of the b decay rates in face of the large available phase space indicates that the off-diagonal elements are indeed very small. The possibility for complete determination of the mixing matrix was brought significantly nearer by the availability of the lifetime information; what is needed now is to reduce the uncertainty of the measurements, which was about 33% for both experiments. We describe here an extension of the b lifetime study with the MAC detector, incorporating some new data and improvements in the analysis. 12 references

  15. Multiple-Antenna Interference Cancellation for WLAN with MAC Interference Avoidance in Open Access Networks

    Directory of Open Access Journals (Sweden)

    Alexandr M. Kuzminskiy

    2007-10-01

    Full Text Available The potential of multiantenna interference cancellation receiver algorithms for increasing the uplink throughput in WLAN systems such as 802.11 is investigated. The medium access control (MAC in such systems is based on carrier sensing multiple-access with collision avoidance (CSMA/CA, which itself is a powerful tool for the mitigation of intrasystem interference. However, due to the spatial dependence of received signal strengths, it is possible for the collision avoidance mechanism to fail, resulting in packet collisions at the receiver and a reduction in system throughput. The CSMA/CA MAC protocol can be complemented in such scenarios by interference cancellation (IC algorithms at the physical (PHY layer. The corresponding gains in throughput are a result of the complex interplay between the PHY and MAC layers. It is shown that semiblind interference cancellation techniques are essential for mitigating the impact of interference bursts, in particular since these are typically asynchronous with respect to the desired signal burst. Semiblind IC algorithms based on second- and higher-order statistics are compared to the conventional no-IC and training-based IC techniques in an open access network (OAN scenario involving home and visiting users. It is found that the semiblind IC algorithms significantly outperform the other techniques due to the bursty and asynchronous nature of the interference caused by the MAC interference avoidance scheme.

  16. Multiple-Antenna Interference Cancellation for WLAN with MAC Interference Avoidance in Open Access Networks

    Directory of Open Access Journals (Sweden)

    Kuzminskiy Alexandr M

    2007-01-01

    Full Text Available The potential of multiantenna interference cancellation receiver algorithms for increasing the uplink throughput in WLAN systems such as 802.11 is investigated. The medium access control (MAC in such systems is based on carrier sensing multiple-access with collision avoidance (CSMA/CA, which itself is a powerful tool for the mitigation of intrasystem interference. However, due to the spatial dependence of received signal strengths, it is possible for the collision avoidance mechanism to fail, resulting in packet collisions at the receiver and a reduction in system throughput. The CSMA/CA MAC protocol can be complemented in such scenarios by interference cancellation (IC algorithms at the physical (PHY layer. The corresponding gains in throughput are a result of the complex interplay between the PHY and MAC layers. It is shown that semiblind interference cancellation techniques are essential for mitigating the impact of interference bursts, in particular since these are typically asynchronous with respect to the desired signal burst. Semiblind IC algorithms based on second- and higher-order statistics are compared to the conventional no-IC and training-based IC techniques in an open access network (OAN scenario involving home and visiting users. It is found that the semiblind IC algorithms significantly outperform the other techniques due to the bursty and asynchronous nature of the interference caused by the MAC interference avoidance scheme.

  17. Towards Energy Efficient Cognitive Radio Systems

    KAUST Repository

    Alabbasi, AbdulRahman

    2016-07-14

    Cognitive radio (CR) is a cutting-edge wireless communication technology that adopts several existing communication concepts in order to efficiently utilize the spectrum and meet the users demands of high throughput and real-time systems. Conventionally, high throughput demands are met through adopting broadband and multi-antenna technologies such as, orthogonal frequency division multiplexing (OFDM) and Multi-Input Multi-Output (MIMO). Whereas, real-time application demands are met by analyzing metrics which characterize the delay limited channels, such as, outage probability over block-fading channels. Being an environmental friendly technology, energy efficiency metrics should be considered in the design of a CR application. This thesis tackles the energy efficiency of CR system from different aspects, utilizing different measuring metrics and constrains. Under the single-input single-output (SISO) OFDM we minimized the energy per goodbit (EPG) metric subject to several power and Quality of Service (QoS) constraints. In this approach, the minimum EPG metric is optimized via proposing two optimal and sub-optimal resource allocation schemes. We consider several parameters as optimization variables, such as, power policy, sensing threshold, and channel quality threshold. We also captured the impact of involving the media access control (MAC) layers parameters, such as, frame length, in the minimization of a modified EPG metric. Also, a MAC protocol, i.e., hybrid automatic repeat request (HARQ), and the associated power consumption of the retransmission mechanism is considered in the formulation of the problem. In this context, the optimal power and frame length are derived to minimize the modified EPG while considering several spectrum-sharing scenarios, which depend on sensing information. In MIMO based CR system, we maximized capacity to power ratio (CPR) (as an energy efficiency (EE) metric) subject to several power and QoS constraints. In this context, the

  18. Installing Git under MacOS

    OpenAIRE

    Fitzpatrick, Benjamin

    2015-01-01

    Step by step guide to installing the version control software Git under the Macintosh Operating System MacOS X (and later). Includes a seqeunce of screenshots with hand drawn arrows ;-) These slides are part of the materials for an Introductory course on the R language and environment for statistial computing. Free and Open Source materials for this course hosted on GitHub: https://github.com/brfitzpatrick/Intro_to_R

  19. Split Course Hyperfractionated Accelerated Radio-Chemotherapy (SCHARC) for patients with advanced head and neck cancer: Influence of protocol deviations and hemoglobin on overall survival, a retrospective analysis

    OpenAIRE

    Stadler, Peter; Putnik, Kurt; Kreimeyer, Thore; Sprague, Lisa D; Koelbl, Oliver; Schäfer, Christof

    2006-01-01

    Abstract Background The advantage of hyperfractionated accelerated radiation therapy for advanced head and neck cancer has been reported. Furthermore, randomized trials and meta-analyses have confirmed the survival benefit of additional chemotherapy to radiotherapy. We retrospectively analyzed the efficiency and toxicity of the Regensburg standard therapy protocol "SCHARC" and the overall survival of our patients. Methods From 1997 to 2004, 64 patients suffering from advanced head and neck ca...

  20. Visualization of integrin Mac-1 in vivo.

    Science.gov (United States)

    Lim, Kihong; Hyun, Young-Min; Lambert-Emo, Kris; Topham, David J; Kim, Minsoo

    2015-11-01

    β2 integrins play critical roles in migration of immune cells and in the interaction with other cells, pathogens, and the extracellular matrix. Among the β2 integrins, Mac-1 (Macrophage antigen-1), composed of CD11b and CD18, is mainly expressed in innate immune cells and plays a major role in cell migration and trafficking. In order to image Mac-1-expressing cells both in live cells and mouse, we generated a knock-in (KI) mouse strain expressing CD11b conjugated with monomeric yellow fluorescent protein (mYFP). Expression of CD11b-mYFP protein was confirmed by Western blot and silver staining of CD11b-immunoprecipitates and total cell lysates from the mouse splenocytes. Mac-1-mediated functions of the KI neutrophils were comparable with those in WT cells. The fluorescence intensity of CD11b-mYFP was sufficient to image CD11b expressing cells in live mice using intravital two-photon microscopy. In vitro, dynamic changes in the intracellular localization of CD11b molecules could be measured by epifluorescent microscopy. Finally, CD11b-expressing immune cells from tissue were easily detected by flow cytometry without anti-CD11b antibody staining. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Split Course Hyperfractionated Accelerated Radio-Chemotherapy (SCHARC for patients with advanced head and neck cancer: Influence of protocol deviations and hemoglobin on overall survival, a retrospective analysis

    Directory of Open Access Journals (Sweden)

    Sprague Lisa D

    2006-12-01

    Full Text Available Abstract Background The advantage of hyperfractionated accelerated radiation therapy for advanced head and neck cancer has been reported. Furthermore, randomized trials and meta-analyses have confirmed the survival benefit of additional chemotherapy to radiotherapy. We retrospectively analyzed the efficiency and toxicity of the Regensburg standard therapy protocol "SCHARC" and the overall survival of our patients. Methods From 1997 to 2004, 64 patients suffering from advanced head and neck cancer (88 % stage IV, 12 % stage III were assigned to receive the SCHARC protocol. Around half of the patients were diagnosed with oro-hypopharynx carcinoma (52 %, one third with tongue and floor of mouth tumors (29 % and one fifth (19 % suffered from H & N cancer at other sites. The schedule consisted of one therapy block with 30 Gy in 20 fractions over a two week period with concomitant chemotherapy (d 1–5: 20 mg/m2/d DDP + 750–1000 mg/m2/d 5FU (cont. infusion. This therapy block was repeated after a fortnight break up to a cumulative dose of 60 Gy and followed by a boost up to 70 Gy (69–70.5 Gy. All patients assigned to this scheme were included in the survival evaluation. Results Forty patients (63 % received both radiation and chemotherapy according to the protocol. The mean follow up was 2.3 years (829 d and the median follow up was 1.9 years (678 d, respectively. The analysis of survival revealed an estimated 3 year overall survival rate of 57 %. No patient died of complications, 52 patients (80 % had acute grade 2–3 mucositis, and 33 patients (58 % suffered from acute grade 3 skin toxicity. Leucopenia was no major problem (mean nadir 3.4 g/nl, no patient 10.5 g/dl and for patients who completed the protocol. Conclusion The SCHARC protocol was effective in patients diagnosed with advanced head and neck cancer. It led to long-term disease control and survival in about 50 % of the patients with significant but acceptable toxicity. Most patients

  2. Split Course Hyperfractionated Accelerated Radio-Chemotherapy (SCHARC) for patients with advanced head and neck cancer: Influence of protocol deviations and hemoglobin on overall survival, a retrospective analysis

    International Nuclear Information System (INIS)

    Stadler, Peter; Putnik, Kurt; Kreimeyer, Thore; Sprague, Lisa D; Koelbl, Oliver; Schäfer, Christof

    2006-01-01

    The advantage of hyperfractionated accelerated radiation therapy for advanced head and neck cancer has been reported. Furthermore, randomized trials and meta-analyses have confirmed the survival benefit of additional chemotherapy to radiotherapy. We retrospectively analyzed the efficiency and toxicity of the Regensburg standard therapy protocol 'SCHARC' and the overall survival of our patients. From 1997 to 2004, 64 patients suffering from advanced head and neck cancer (88 % stage IV, 12 % stage III) were assigned to receive the SCHARC protocol. Around half of the patients were diagnosed with oro-hypopharynx carcinoma (52 %), one third with tongue and floor of mouth tumors (29 %) and one fifth (19 %) suffered from H & N cancer at other sites. The schedule consisted of one therapy block with 30 Gy in 20 fractions over a two week period with concomitant chemotherapy (d 1–5: 20 mg/m 2 /d DDP + 750–1000 mg/m 2 /d 5FU (cont. infusion). This therapy block was repeated after a fortnight break up to a cumulative dose of 60 Gy and followed by a boost up to 70 Gy (69–70.5 Gy). All patients assigned to this scheme were included in the survival evaluation. Forty patients (63 %) received both radiation and chemotherapy according to the protocol. The mean follow up was 2.3 years (829 d) and the median follow up was 1.9 years (678 d), respectively. The analysis of survival revealed an estimated 3 year overall survival rate of 57 %. No patient died of complications, 52 patients (80 %) had acute grade 2–3 mucositis, and 33 patients (58 %) suffered from acute grade 3 skin toxicity. Leucopenia was no major problem (mean nadir 3.4 g/nl, no patient < 1.0 g/nl) and the mean hemoglobin value decreased from 13.2 to 10.5 g/dl. Univariate analysis of survival showed a better outcome for patients with a hemoglobin nadir >10.5 g/dl and for patients who completed the protocol. The SCHARC protocol was effective in patients diagnosed with advanced head and neck cancer. It led

  3. Split course hyperfractionated accelerated radio-chemotherapy (SCHARC) for patients with advanced head and neck cancer: influence of protocol deviations and hemoglobin on overall survival, a retrospective analysis.

    Science.gov (United States)

    Stadler, Peter; Putnik, Kurt; Kreimeyer, Thore; Sprague, Lisa D; Koelbl, Oliver; Schäfer, Christof

    2006-12-07

    The advantage of hyperfractionated accelerated radiation therapy for advanced head and neck cancer has been reported. Furthermore, randomized trials and meta-analyses have confirmed the survival benefit of additional chemotherapy to radiotherapy. We retrospectively analyzed the efficiency and toxicity of the Regensburg standard therapy protocol "SCHARC" and the overall survival of our patients. From 1997 to 2004, 64 patients suffering from advanced head and neck cancer (88 % stage IV, 12 % stage III) were assigned to receive the SCHARC protocol. Around half of the patients were diagnosed with oro-hypopharynx carcinoma (52 %), one third with tongue and floor of mouth tumors (29 %) and one fifth (19 %) suffered from H & N cancer at other sites. The schedule consisted of one therapy block with 30 Gy in 20 fractions over a two week period with concomitant chemotherapy (d 1-5: 20 mg/m2/d DDP + 750-1000 mg/m2/d 5FU (cont. infusion). This therapy block was repeated after a fortnight break up to a cumulative dose of 60 Gy and followed by a boost up to 70 Gy (69-70.5 Gy). All patients assigned to this scheme were included in the survival evaluation. Forty patients (63 %) received both radiation and chemotherapy according to the protocol. The mean follow up was 2.3 years (829 d) and the median follow up was 1.9 years (678 d), respectively. The analysis of survival revealed an estimated 3 year overall survival rate of 57 %. No patient died of complications, 52 patients (80 %) had acute grade 2-3 mucositis, and 33 patients (58 %) suffered from acute grade 3 skin toxicity. Leucopenia was no major problem (mean nadir 3.4 g/nl, no patient hemoglobin value decreased from 13.2 to 10.5 g/dl. Univariate analysis of survival showed a better outcome for patients with a hemoglobin nadir >10.5 g/dl and for patients who completed the protocol. The SCHARC protocol was effective in patients diagnosed with advanced head and neck cancer. It led to long-term disease control and survival in

  4. Development of high yielding Soybean variety MACS 450 by using Kalitur mutant-MACS 111

    International Nuclear Information System (INIS)

    Raut, V.M.; Taware, S.P.; Halvankar, G.B.; Varghese, Philips

    2000-01-01

    A mutant variety -MACS 111 developed by treating seeds of indigenous black seeded 'Kalitur' variety with gamma irradiation + Ethyleneimine was used in development of high yielding varieties. MACS 450 a promising high yielding variety was selected from Bragg x MACS 111 cross by pedigree selection method. This variety gave the highest average seed yield in station trials (3422 kg/ha), coordinated breeding trials (2361 kg/ha) and varieties cum plant population trial (2215 kg/ha). On the basis of its performance in these trials it was released for commercial cultivation in Southern India. On all India basis, it also recorded the highest seed yield of 4076 kg/ha and 3582 kg/ha in Front line Demonstrations conducted on the farmers' field during 1998 and 1999 respectively. (author)

  5. A Novel Video Data-Source Authentication Model Based on Digital Watermarking and MAC in Multicast

    Institute of Scientific and Technical Information of China (English)

    ZHAO Anjun; LU Xiangli; GUO Lei

    2006-01-01

    A novel video data authentication model based on digital video watermarking and MAC (message authentication code) in multicast protocol is proposed in this paper. The digital watermarking which composes of the MAC of the significant video content, the key and instant authentication data is embedded into the insignificant video component by the MLUT (modified look-up table) video watermarking technology. We explain a method that does not require storage of each data packet for a time, thus making receiver not vulnerable to DOS (denial of service) attack. So the video packets can be authenticated instantly without large volume buffer in the receivers. TESLA(timed efficient stream loss-tolerant authentication) does not explain how to select the suitable value for d, which is an important parameter in multicast source authentication. So we give a method to calculate the key disclosure delay (number of intervals). Simulation results show that the proposed algorithms improve the performance of data source authentication in multicast.

  6. One of the First Portable Macs

    CERN Multimedia

    1989-01-01

    It was one of the first portable macs released. The Portable had many new advances in mobile computing : The display was crispy clear, and looked beautiful when used in daylight ; The Portable came with a Lead-acid gel/cell battery that could run a anywhere from 6 -12 hours ; It supported to internal hard drives, and an external one. The reaction to the laptop was weak because it was slow, it had no capacity for expansion, it weighed heavily, its price was expensive. It has been stayed 1 year and half on the market.

  7. The periplasmic membrane proximal domain of MacA acts as a switch in stimulation of ATP hydrolysis by MacB transporter

    OpenAIRE

    Modali, Sita D.; Zgurskaya, Helen I.

    2011-01-01

    Escherichia coli MacAB-TolC is a tri-partite macrolide efflux transporter driven by hydrolysis of ATP. In this complex, MacA is the periplasmic membrane fusion protein that stimulates the activity of MacB transporter and establishes the link with the outer membrane channel TolC. The molecular mechanism by which MacA stimulates MacB remains unknown. Here, we report that the periplasmic membrane proximal domain of MacA plays a critical role in functional MacA-MacB interactions and stimulation o...

  8. Turning the Big Mac Index into the Medical MAC Index | Wilson ...

    African Journals Online (AJOL)

    Objective: The purpose of this study was to create a global medical earnings index, called the Medical MAC Index, to enable a comparison of what medical specialists earn in the countries included in the study. Design: The study gathered data on the earnings of specialist anaesthetists employed in state hospitals with five ...

  9. Essential Mac OS X panther server administration integrating Mac OS X server into heterogeneous networks

    CERN Document Server

    Bartosh, Michael

    2004-01-01

    If you've ever wondered how to safely manipulate Mac OS X Panther Server's many underlying configuration files or needed to explain AFP permission mapping--this book's for you. From the command line to Apple's graphical tools, the book provides insight into this powerful server software. Topics covered include installation, deployment, server management, web application services, data gathering, and more

  10. Solar Radio

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists monitor the structure of the solar corona, the outer most regions of the Sun's atmosphere, using radio waves (100?s of MHz to 10?s of GHz). Variations in...

  11. Radio astronomy

    International Nuclear Information System (INIS)

    Parijskij, Y.N.; Gossachinskij, I.V.; Zuckerman, B.; Khersonsky, V.K.; Pustilnik, S.; Robinson, B.J.

    1976-01-01

    A critical review of major developments and discoveries in the field of radioastronomy during the period 1973-1975 is presented. The report is presented under the following headings:(1) Continuum radiation from the Galaxy; (2) Neutral hydrogen, 21 cm (galactic and extragalactic) and recombination lines; (3) Radioastronomy investigations of interstellar molecules; (4) Extragalactic radio astronomy and (6) Development in radio astronomy instruments. (B.R.H.)

  12. Mac OS X Snow Leopard Server For Dummies

    CERN Document Server

    Rizzo, John

    2009-01-01

    Making Everything Easier!. Mac OS® X Snow Leopard Server for Dummies. Learn to::;. Set up and configure a Mac network with Snow Leopard Server;. Administer, secure, and troubleshoot the network;. Incorporate a Mac subnet into a Windows Active Directory® domain;. Take advantage of Unix® power and security. John Rizzo. Want to set up and administer a network even if you don't have an IT department? Read on!. Like everything Mac, Snow Leopard Server was designed to be easy to set up and use. Still, there are so many options and features that this book will save you heaps of time and effort. It wa

  13. A Mobile Automated Characterization System (MACS) for indoor floor characterization

    International Nuclear Information System (INIS)

    Richardson, B.S.; Haley, D.C.; Dudar, A.M.; Ward, C.R.

    1995-01-01

    The Savannah River Technology Center (SRTC) and Oak Ridge National Laboratory are developing an advanced Mobile Automated Characterization System (MACS) to characterize indoor contaminated floors. MACS is based upon Semi-Intelligent Mobile Observing Navigator (SIMON), an earlier floor characterization system developed at SRTC. MACS will feature enhanced navigation systems, operator interface, and an interface to simplify integration of additional sensors. The enhanced navigation system will provide the capability to survey large open areas much more accurately than is now possible with SIMON, which is better suited for hallways and corridors that provide the means for recalibrating position and heading. MACS operator interface is designed to facilitate MACS's use as a tool for health physicists, thus eliminating the need for additional training in the robot's control language. Initial implementation of MACS will use radiation detectors. Additional sensors, such as PCB sensors currently being developed, will be integrated on MACS in the future. Initial use of MACS will be focused toward obtaining comparative results with manual methods. Surveys will be conducted both manually and with MACS to compare relative costs and data quality. While clear cost benefits anticipated, data quality benefits should be even more significant

  14. A reliable, delay bounded and less complex communication protocol for multicluster FANETs

    Directory of Open Access Journals (Sweden)

    Wajiya Zafar

    2017-02-01

    Full Text Available Recently, Flying Ad-hoc Networks (FANETs, enabling ad-hoc networking between Unmanned Aerial Vehicles (UAVs is gaining importance in several military and civilian applications. The sensitivity of the applications requires adaptive; efficient; delay bounded and scalable communication network among UAVs for data transmission. Due to communication protocol complexity; rigidity; cost of commercial-off-the-shelf (COT components; limited radio bandwidth; high mobility and computational resources; maintaining the desired level of Quality of Service (QoS becomes a daunting task. For the first time in this research we propose multicluster FANETs for efficient network management; the proposed scheme considerably reduces communication cost and optimizes network performance as well as exploit low power; less complex and low cost IEEE 802.15.4 (MAC protocol for intercluster and intracluster communication. In this research both beacon enabled mode and beaconless modes have been investigated with Guaranteed Time Slots (GTS and virtual Time Division Multiple Access (TDMA respectively. The methodology plays a key role towards reserving bandwidth for latency critical applications; eliminate collisions and medium access delays. Moreover analysis ad-hoc routing protocols including two proactive (OLSR, DSDV and one reactive (AODV is also presented. The results shows that the proposed scheme guarantees high packet delivery ratios while maintaining acceptable levels of latency requirements comparable with more complex and dedicatedly designed protocols in literature.

  15. Listen and talk full-duplex cognitive radio networks

    CERN Document Server

    Liao, Yun; Han, Zhu

    2016-01-01

    This brief focuses on the use of full-duplex radio in cognitive radio networks, presenting a novel spectrum sharing protocol that allows the secondary users to simultaneously sense and access the vacant spectrum. This protocol, called “Listen-and-talk” (LAT), is evaluated by both mathematical analysis and computer simulations in comparison with other existing protocols, including the listen-before-talk protocol. In addition to LAT-based signal processing and resource allocation, the brief discusses techniques such as spectrum sensing and dynamic spectrum access. The brief proposes LAT as a suitable access scheme for cognitive radio networks, which can support the quality-of-service requirements of these high priority applications. Fundamental theories and key techniques of cognitive radio networks are also covered. Listen and Talk: Full-duplex Cognitive Radio Networks is designed for researchers, developers, and professionals involved in cognitive radio networks. Advanced-level students studying signal pr...

  16. Steven MacCall: Winner of LJ's 2010 Teaching Award

    Science.gov (United States)

    Berry, John N., III

    2010-01-01

    This article profiles Steven L. MacCall, winner of "Library Journal's" 2010 Teaching Award. An associate professor at the School of Library and Information Studies (SLIS) at the University of Alabama, Tuscaloosa, MacCall was nominated by Kathie Popadin, known as "Kpop" to the members of her cohort in the online MLIS program at SLIS. Sixteen of…

  17. Paradox applications integration ATP's for MAC and mass balance programs

    International Nuclear Information System (INIS)

    Russell, V.K.; Mullaney, J.E.

    1994-01-01

    The K Basins Materials Accounting (MAC) and Material Balance (MBA) database system were set up to run under one common applications program. This Acceptance Test Plan (ATP) describes how the code was to be tested to verify its correctness. The scope of the tests is minimal, since both MAC and MBA have already been tested in detail as stand-alone programs

  18. Lifetime tests for MAC vertex chamber

    International Nuclear Information System (INIS)

    Nelson, H.

    1986-01-01

    A vertex chamber for MAC was proposed in fall 1983 to increase precision in the measurement of the B hadron and tau lepton lifetimes. The chamber had to be placed within the existing central drift chamber, making access for repairs difficult and costly. Therefore for detector elements thin-walled aluminized mylar drift tubes (straws) were used because of their simplicity and robustness. The diameter of the drift tubes was 6.9 mm. The radial extent of the proposed chamber was from 3 cm to 10 cm, the inner wall of the central drift. It was clear that radiation levels, from synchrotron x-rays and overfocussed electrons, were potentially high. Since the drift distance is short in the straws, it was desirable to operate them at the highest possible gas gain, to achieve the best spatial resolution. There was a likelihood of drawing large currents in the chamber and thus causing radiation damage. Therefore a study of radiation hardness under the conditions of their proposed design was undertaken. In tests, argon-hydrocarbon mixtures consistently became unusable at ∼0.05 C/cm collected charge, due to anode buildup. Argon-CO 2 mixtures, while underquenched, were operational to 0.25 C/cm, at which point loss of cathode material became intolerable. Argon-xenon-CO 2 proved to be quenched as well as argon-hydrocarbons, but was limited by cathode damage. The MAC vertex chamber has operated at a distance of 4.6 cm from the e + e - interaction point at PEP for two years and has shown no aging effects

  19. A Camac-VME-MacIntosh data acquisition system for nuclear experiments

    International Nuclear Information System (INIS)

    Anzalone, A.; Giustolisi, F.

    1989-01-01

    A multiprocessor system for data acquisition and analysis in low energy nuclear physics has been realized at the Laboratorio Nazionale del Sud. the system is built around Camac, VME-bus and MacIntosh PC. A multiprocessor software has been developed, using RTF, Macsys and Cern cross-software. The execution of several programs which run on several VME-CPU's and on an external PC, is coordinated by a mail box protocol. No operating system is used on the VME-CPU's

  20. Radio astronomy

    CERN Document Server

    Alder, Berni

    1975-01-01

    Methods in Computational Physics, Volume 14: Radio Astronomy is devoted to the role of the digital computer both as a control device and as a calculator in addressing problems related to galactic radio noise. This volume contains four chapters and begins with a technical description of the hardware and the special data-handling problems of using radioheliography, with an emphasis on a selection of observational results obtained with the Culgoora radioheliograph and their significance to solar physics and to astrophysics in general. The subsequent chapter examines interstellar dispersion, i

  1. GENETIC FINGERPRINTING OF MYCOBACTERIUM AVIUM COMPLEX (MAC) ORGANISMS ISOLATED FROM HOSPITAL PATIENTS AND THE ENVIRONMENT

    Science.gov (United States)

    A particularly pathogenic group of mycobacteria belong to the Mycobacterium avium complex (MAC), which includes M. avium and M. intracellulare. MAC organisms cause disease in children, the elderly, and immuno-compromised individuals. A critical step in preventing MAC infections...

  2. Design and Implementation of an Enhanced 802.11 MAC Architecture for Single-Hop Wireless Networks

    Directory of Open Access Journals (Sweden)

    Ralph Bernasconi

    2007-01-01

    Full Text Available Due to its extreme simplicity and flexibility, the IEEE 802.11 standard is the dominant technology to implement both infrastructure-based WLANs and single-hop ad hoc networks. In spite of its popularity, there is a vast literature demonstrating the shortcomings of using the 802.11 technology in such environments, such as dramatic degradation of network capacity as contention increases and vulnerability to external interferences. Therefore, the design of enhancements and optimizations for the original 802.11 MAC protocol has been a very active research area in the last years. However, all these modifications to the 802.11 MAC protocol were validated only through simulations and/or analytical investigations. In this paper, we present a very unique work as we have designed a flexible hardware/software platform, fully compatible with current implementations of the IEEE 802.11 technology, which we have used to concretely implement and test an enhanced 802.11 backoff algorithm. Our experimental results clearly show that the enhanced mechanism outperforms the standard 802.11 MAC protocol in real scenarios.

  3. A Novel Spectrally Efficient Asynchronous Multi-Channel MAC Using a Half-Duplex Transceiver for Wireless Networks

    Directory of Open Access Journals (Sweden)

    Abdullah Devendiran

    2018-01-01

    Full Text Available Multi-channel medium access control (MAC protocols maximize network performance by enabling concurrent wireless transmissions over non-interfering channels. Despite physical layer advancements, the underlying IEEE 802.11 MAC standard cannot fully exploit features and support high-performance applications. In this work, we propose the novel spectrally efficient asynchronous multi-channel MAC (SA-MMAC protocol for wireless networks using a single half-duplex transceiver. A full-duplex mode of operation on data channels reduces the signaling overhead and boosts the spectrum efficiency. A revamped contention mechanism of IEEE 802.11 addresses the multi-channel hidden terminal problem, and a jamming signal from the receiver addresses the collisions in control signals. Furthermore, the control channel is used for data transmissions to increase the bandwidth utilization but under a restricted half-duplex mode to avoid causing a bottleneck situation. The simulator is tested for correctness. The results suggest that the protocol can work well on 3, 4, or 12 concurrent channels with high node density, providing about 12.5 times more throughput than IEEE 802.11 and 18% to 95% more throughput than its multi-channel variants under saturated traffic conditions.

  4. Dynamic-Threshold-Limited Timed-Token (DTLTT) Protocol | Kalu ...

    African Journals Online (AJOL)

    An improved version of the Static-Threshold-Limited On-Demand Guaranteed Service Timed-Token (STOGSTT) Media Access Control (MAC) protocol for channel capacity allocation to the asynchronous trac in Multiservice Local Area Network (MLANs) was developed and analyzed. TLODGSTT protocol uses static value of ...

  5. Asymptotic performance modelling of DCF protocol with prioritized channel access

    Science.gov (United States)

    Choi, Woo-Yong

    2017-11-01

    Recently, the modification of the DCF (Distributed Coordination Function) protocol by the prioritized channel access was proposed to resolve the problem that the DCF performance worsens exponentially as more nodes exist in IEEE 802.11 wireless LANs. In this paper, an asymptotic analytical performance model is presented to analyze the MAC performance of the DCF protocol with the prioritized channel access.

  6. Increased NMDA receptor inhibition at an increased Sevoflurane MAC

    Directory of Open Access Journals (Sweden)

    Brosnan Robert J

    2012-06-01

    Full Text Available Abstract Background Sevoflurane potently enhances glycine receptor currents and more modestly decreases NMDA receptor currents, each of which may contribute to immobility. This modest NMDA receptor antagonism by sevoflurane at a minimum alveolar concentration (MAC could be reciprocally related to large potentiation of other inhibitory ion channels. If so, then reduced glycine receptor potency should increase NMDA receptor antagonism by sevoflurane at MAC. Methods Indwelling lumbar subarachnoid catheters were surgically placed in 14 anesthetized rats. Rats were anesthetized with sevoflurane the next day, and a pre-infusion sevoflurane MAC was measured in duplicate using a tail clamp method. Artificial CSF (aCSF containing either 0 or 4 mg/mL strychnine was then infused intrathecally at 4 μL/min, and the post-infusion baseline sevoflurane MAC was measured. Finally, aCSF containing strychnine (either 0 or 4 mg/mL plus 0.4 mg/mL dizocilpine (MK-801 was administered intrathecally at 4 μL/min, and the post-dizocilpine sevoflurane MAC was measured. Results Pre-infusion sevoflurane MAC was 2.26%. Intrathecal aCSF alone did not affect MAC, but intrathecal strychnine significantly increased sevoflurane requirement. Addition of dizocilpine significantly decreased MAC in all rats, but this decrease was two times larger in rats without intrathecal strychnine compared to rats with intrathecal strychnine, a statistically significant (P  Conclusions Glycine receptor antagonism increases NMDA receptor antagonism by sevoflurane at MAC. The magnitude of anesthetic effects on a given ion channel may therefore depend on the magnitude of its effects on other receptors that modulate neuronal excitability.

  7. MacRuby Ruby and Cocoa on OS X

    CERN Document Server

    Aimonetti, Matt

    2011-01-01

    Want to build native Mac OS X applications with a sleek, developer-friendly alternative to Objective-C? MacRuby is an ideal choice. This in-depth guide shows you how Apple's implementation of Ruby gives you access to all the features available to Objective-C programmers. You'll get clear, detailed explanations of MacRuby, including quick programming techniques such as prototyping. Perfect for programmers at any level, this book is packed with code samples and complete project examples. If you use Ruby, you can tap your skills to take advantage of Interface Builder, Cocoa libraries, the Objec

  8. iMac G3 Blueberry 350MHz

    CERN Multimedia

    2000-01-01

    The iMac G3 is an all-in-one personal computer, encompassing both the monitor and the computer in one package. It allowed to revitalize the Apple brand that was in decline and close to financial ruin. Originally released in striking bondi blue and later a range of other translucent plastic envelopes in bright colors. The iMac comes with a keyboard and mouse matching the color of the case. The iMac G3 was sold from 1998 to 2003 and has been updated many times.

  9. The MacNuclide nuclear data environment

    International Nuclear Information System (INIS)

    Stone, C.A.

    1992-01-01

    Advance in technology have produced intriguing tools that can be applied to problems in nuclear science. Information management in nuclear science is an example of how technology is not quickly exploited. The U.S. Department of Energy supports an extensive program to evaluate published nuclear properties and store them in an electronic data base. Much of the evaluation effort has focused on producing the journal Nuclear Data Sheets and the publication Table of Isotopes. Although the electronic data base can itself be a valuable source of information, the software used to access is was designed using decades-old technologies. The authors of this paper have developed a novel data-base management system for nuclear properties. The application is known as MacNuclide. It is a nuclear data-base environment that uses the highly interactive and intuitive windowing environmentsof desk-top computers. The environment is designed around that image of the chart of nuclides. Questions are posed to the data base by placing constraints on properties and defining collections of nuclides to be used in data-base seraches. Results are displayed either as a simple list of nuclides that meet the imposed constraints or as a color chart of nuclides

  10. Infecting Windows, Linux & Mac in one go

    CERN Multimedia

    Computer Security Team

    2012-01-01

    Still love bashing on Windows as you believe it is an insecure operating system? Hold on a second! Just recently, a vulnerability has been published for Java 7.   It affects Windows/Linux PCs and Macs, Internet Explorer, Safari and Firefox. In fact, it affects all computers that have enabled the Java 7 plug-in in their browser (Java 6 and earlier is not affected). Once you visit a malicious website (and there are plenty already out in the wild), your computer is infected… That's "Game Over" for you.      And this is not the first time. For a while now, attackers have not been targeting the operating system itself, but rather aiming at vulnerabilities inherent in e.g. your Acrobat Reader, Adobe Flash or Java programmes. All these are standard plug-ins added into your favourite web browser which make your web-surfing comfortable (or impossible when you un-install them). A single compromised web-site, however, is sufficient to prob...

  11. A Unified NET-MAC-PHY Cross-layer Framework for Performance Evaluation of Multi-hop Ad hoc WLANs

    Directory of Open Access Journals (Sweden)

    Rachid El-Azouzi

    2014-09-01

    Full Text Available Most of the existing works have been evaluated the performance of 802.11 multihop networks by considering the MAC layer or network layer separately. Knowing the nature of the multi-hop ad hoc networks, many factors in different layers are crucial for study the performance of MANET. In this paper we present a new analytic model for evaluating average end-to-end throughput in IEEE 802.11e multihop wireless networks. In particular, we investigate an intricate interaction among PHY, MAC and Network layers. For instance, we incorporate carrier sense threshold, transmission power, contention window size, retransmissions retry limit, multi rates, routing protocols and network topology together. We build a general cross-layered framework to represent multi-hop ad hoc networks with asymmetric topology and asymmetric traffic. We develop an analytical model to predict throughput of each connection as well as stability of forwarding queues at intermediate nodes in saturated networks. To the best of our knowledge, it seems that our work is the first wherein general topology and asymmetric parameters setup are considered in PHY/MAC/Network layers. Performance of such a system is also evaluated through simulation. We show that performance measures of the MAC layer are affected by the traffic intensity of flows to be forwarded. More precisely, attempt rate and collision probability are dependent on traffic flows, topology and routing.

  12. Competition at the Wireless Sensor Network MAC Layer: Low Power Probing interfering with X-MAC

    International Nuclear Information System (INIS)

    Zacharias, Sven; Newe, Thomas

    2011-01-01

    Wireless Sensor Networks (WSNs) combine sensors with computer networks and enable very dense, in-situ and live measurements of data over a large area. Since this emerging technology has the potential to be embedded almost everywhere for numberless applications, interference between different networks can become a serious issue. For most WSNs, it is assumed today that the network medium access is non-competitive. On the basis of X-MAC interfered by Low Power Probing, this paper shows the danger and the effects of different sensor networks communicating on a single wireless channel of the 2.4 GHz band, which is used by the IEEE 802.15.4 standard.

  13. Competition at the Wireless Sensor Network MAC Layer: Low Power Probing interfering with X-MAC

    Energy Technology Data Exchange (ETDEWEB)

    Zacharias, Sven; Newe, Thomas, E-mail: Sven.Zacharias@ul.ie [University of Limerick (Ireland)

    2011-08-17

    Wireless Sensor Networks (WSNs) combine sensors with computer networks and enable very dense, in-situ and live measurements of data over a large area. Since this emerging technology has the potential to be embedded almost everywhere for numberless applications, interference between different networks can become a serious issue. For most WSNs, it is assumed today that the network medium access is non-competitive. On the basis of X-MAC interfered by Low Power Probing, this paper shows the danger and the effects of different sensor networks communicating on a single wireless channel of the 2.4 GHz band, which is used by the IEEE 802.15.4 standard.

  14. Competition at the Wireless Sensor Network MAC Layer: Low Power Probing interfering with X-MAC

    Science.gov (United States)

    Zacharias, Sven; Newe, Thomas

    2011-08-01

    Wireless Sensor Networks (WSNs) combine sensors with computer networks and enable very dense, in-situ and live measurements of data over a large area. Since this emerging technology has the potential to be embedded almost everywhere for numberless applications, interference between different networks can become a serious issue. For most WSNs, it is assumed today that the network medium access is non-competitive. On the basis of X-MAC interfered by Low Power Probing, this paper shows the danger and the effects of different sensor networks communicating on a single wireless channel of the 2.4 GHz band, which is used by the IEEE 802.15.4 standard.

  15. The Radio JOVE Project - Shoestring Radio Astronomy

    Science.gov (United States)

    Thieman, J.; Flagg, R.; Greenman, W.; Higgins, C.; Reyes, F.; Sky, J.

    2010-01-01

    Radio JOVE is an education and outreach project intended to give students and other interested individuals hands-on experience in learning radio astronomy. They can do this through building a radio telescope from a relatively inexpensive kit that includes the parts for a receiver and an antenna as well as software for a computer chart recorder emulator (Radio Skypipe) and other reference materials

  16. Space Telecommunications Radio System STRS Cognitive Radio

    Science.gov (United States)

    Briones, Janette C.; Handler, Louis M.

    2013-01-01

    Radios today are evolving from awareness toward cognition. A software defined radio (SDR) provides the most capability for integrating autonomic decision making ability and allows the incremental evolution toward a cognitive radio. This cognitive radio technology will impact NASA space communications in areas such as spectrum utilization, interoperability, network operations, and radio resource management over a wide range of operating conditions. NASAs cognitive radio will build upon the infrastructure being developed by Space Telecommunication Radio System (STRS) SDR technology. This paper explores the feasibility of inserting cognitive capabilities in the NASA STRS architecture and the interfaces between the cognitive engine and the STRS radio. The STRS architecture defines methods that can inform the cognitive engine about the radio environment so that the cognitive engine can learn autonomously from experience, and take appropriate actions to adapt the radio operating characteristics and optimize performance.

  17. MAC mini acceptance test procedure, software Version 3.0

    International Nuclear Information System (INIS)

    Russell, V.K.

    1994-01-01

    The K Basins Materials Accounting (MAC) programs had some major improvements made to it to organize the main-tables by Location, Canister, and Material. This ATP describes how the code was to be tested to verify its correctness

  18. Mechatronical Aided Concept (MAC) in Intelligent Transport Vehicles Design

    OpenAIRE

    Pavel Pavlasek

    2003-01-01

    This article deals with the principles of synergy effect of mechatronical aided concept (MAC) to the design of intelligent transport vehicles products applying CA technologies and virtual reality design methods. Also includes presentation of intelligent railway vehicle development.

  19. Mac OS X : Tiger edition the missing manual

    CERN Document Server

    Pogue, David

    2005-01-01

    You can set your watch to it: As soon as Apple comes out with another version of Mac OS X, David Pogue hits the streets with another meticulous Missing Manual to cover it with a wealth of detail. The new Mac OS X 10.4, better known as Tiger, is faster than its predecessors, but nothing's too fast for Pogue and Mac OS X: The Missing Manual. There are many reasons why this is the most popular computer book of all time. With its hallmark objectivity, the Tiger Edition thoroughly explores the latest features to grace the Mac OS. Which ones work well and which do not? What should you look for? Th

  20. MAC layer security issues in wireless mesh networks

    Science.gov (United States)

    Reddy, K. Ganesh; Thilagam, P. Santhi

    2016-03-01

    Wireless Mesh Networks (WMNs) have emerged as a promising technology for a broad range of applications due to their self-organizing, self-configuring and self-healing capability, in addition to their low cost and easy maintenance. Securing WMNs is more challenging and complex issue due to their inherent characteristics such as shared wireless medium, multi-hop and inter-network communication, highly dynamic network topology and decentralized architecture. These vulnerable features expose the WMNs to several types of attacks in MAC layer. The existing MAC layer standards and implementations are inadequate to secure these features and fail to provide comprehensive security solutions to protect both backbone and client mesh. Hence, there is a need for developing efficient, scalable and integrated security solutions for WMNs. In this paper, we classify the MAC layer attacks and analyze the existing countermeasures. Based on attacks classification and countermeasures analysis, we derive the research directions to enhance the MAC layer security for WMNs.

  1. Nora Tully MacAlvay--Her Life in the Theatre.

    Science.gov (United States)

    Webb, Dorothy

    1996-01-01

    Recounts the life and times of a pioneer children's theater playwright and fiction author, Nora Tully MacAlvay (1900-86). Points out that her interest in children's theater and children's literature was lifelong and intense. (PA)

  2. MacMillan Pier Transportation Center Feasibility Study.

    Science.gov (United States)

    2006-06-01

    The MacMillan Pier Transportation Center Feasibility Study examines two potential sites (landside and waterside) for a transportation center that provides a range of tourist and traveler information. It would serve as a gateway for Provincetown and t...

  3. After MacIntyre : Kaasaegsest vooruseetikast / Meego Remmel

    Index Scriptorium Estoniae

    Remmel, Meego

    2006-01-01

    Alasdair MacIntyre panus 20. sajandi eetikasse. Tema käsitlus vooruseetikast ja vooruseetilisest perspektiivist, mida on võimalik näha komplekselt, vaadeldes voorust, praktikat, narratiivi ja traditsiooni mõisteid

  4. Big Mac arvestab raha ostujõudu / Harli Uljas

    Index Scriptorium Estoniae

    Uljas, Harli

    2005-01-01

    The Economist võrdleb maailma valuutade suhestamiseks Big Mac'i burgeri hindu 120 riigis, kuna see meetod võimaldab saada ülevaate riikide elanikkonna tegelikust ostujõust. Tabel: Hamburgeri standard

  5. Aeronautical Mobile Airport Communications System (AeroMACS)

    Science.gov (United States)

    Budinger, James M.; Hall, Edward

    2011-01-01

    To help increase the capacity and efficiency of the nation s airports, a secure wideband wireless communications system is proposed for use on the airport surface. This paper provides an overview of the research and development process for the Aeronautical Mobile Airport Communications System (AeroMACS). AeroMACS is based on a specific commercial profile of the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard known as Wireless Worldwide Interoperability for Microwave Access or WiMAX (WiMax Forum). The paper includes background on the need for global interoperability in air/ground data communications, describes potential AeroMACS applications, addresses allocated frequency spectrum constraints, summarizes the international standardization process, and provides findings and recommendations from the world s first AeroMACS prototype implemented in Cleveland, Ohio, USA.

  6. Miniature EVA Software Defined Radio

    Science.gov (United States)

    Pozhidaev, Aleksey

    2012-01-01

    As NASA embarks upon developing the Next-Generation Extra Vehicular Activity (EVA) Radio for deep space exploration, the demands on EVA battery life will substantially increase. The number of modes and frequency bands required will continue to grow in order to enable efficient and complex multi-mode operations including communications, navigation, and tracking applications. Whether conducting astronaut excursions, communicating to soldiers, or first responders responding to emergency hazards, NASA has developed an innovative, affordable, miniaturized, power-efficient software defined radio that offers unprecedented power-efficient flexibility. This lightweight, programmable, S-band, multi-service, frequency- agile EVA software defined radio (SDR) supports data, telemetry, voice, and both standard and high-definition video. Features include a modular design, an easily scalable architecture, and the EVA SDR allows for both stationary and mobile battery powered handheld operations. Currently, the radio is equipped with an S-band RF section. However, its scalable architecture can accommodate multiple RF sections simultaneously to cover multiple frequency bands. The EVA SDR also supports multiple network protocols. It currently implements a Hybrid Mesh Network based on the 802.11s open standard protocol. The radio targets RF channel data rates up to 20 Mbps and can be equipped with a real-time operating system (RTOS) that can be switched off for power-aware applications. The EVA SDR's modular design permits implementation of the same hardware at all Network Nodes concept. This approach assures the portability of the same software into any radio in the system. It also brings several benefits to the entire system including reducing system maintenance, system complexity, and development cost.

  7. THE INFLUENCE OF MAC BUFFER ON THE CONTENTION-BASED ACCESS SCHEME WITH BURSTING OPTION FOR IEEE 802.11E WIRELESS NETWORKS

    Directory of Open Access Journals (Sweden)

    S. SELVAKENNEDY

    2006-12-01

    Full Text Available Wireless LANs are increasingly being used for inelastic applications. Currently, there is little support for quality of service in the IEEE 802.11 MAC protocol, and IEEE task group E has defined the 802.11e MAC extension. Enhanced distributed channel access (EDCA is a contention-based scheme of the 802.11e standard. To allow a station to transmit more than one frame from a single contention, an optional feature known as controlled frame-bursting (CFB is introduced in the standard. In this paper, we initially performed an average analysis to determine a suitable burst duration limit. Then, a detailed evaluation and comparison of the EDCA protocol with the CFB option is carried out through simulation to quantify its performance gain. The impact of the MAC transmit buffer size is also incorporated. Accordingly, we have proposed a suitable approach to guide the configuration of the burst duration limit. It is demonstrated that an optimized CFB configuration allows the MAC protocol to achieve 30% more capacity than the basic EDCA scheme.

  8. Cognitive Radio RF: Overview and Challenges

    Directory of Open Access Journals (Sweden)

    Van Tam Nguyen

    2012-01-01

    Full Text Available Cognitive radio system (CRS is a radio system which is aware of its operational and geographical environment, established policies, and its internal state. It is able to dynamically and autonomously adapt its operational parameters and protocols and to learn from its previous experience. Based on software-defined radio (SDR, CRS provides additional flexibility and offers improved efficiency to overall spectrum use. CRS is a disruptive technology targeting very high spectral efficiency. This paper presents an overview and challenges of CRS with focus on radio frequency (RF section. We summarize the status of the related regulation and standardization activities which are very important for the success of any emerging technology. We point out some key research challenges, especially implementation challenges of cognitive radio (CR. A particular focus is on RF front-end, transceiver, and analog-to-digital and digital-to-analog interfaces which are still a key bottleneck in CRS development.

  9. Learning Unix for Mac OS X Tiger Unlock the Power of Unix

    CERN Document Server

    Taylor, Dave

    2005-01-01

    Thoroughly revised and updated for Mac OS X Tiger, this new edition introduces Mac users to the Terminal application and shows you how to navigate the command interface, explore hundreds of Unix applications that come with the Mac, and, most importantly, how to take advantage of both the Mac and Unix interfaces. If you want to master the command-line, this gentle guide to using Unix on Mac OS X Tiger is well worth its cover price

  10. The radio universe

    International Nuclear Information System (INIS)

    Worvill, R.

    1977-01-01

    Elementary description of the development of radioastronomy, radio waves from the sun and planets, the use of radio telescopes and the detection of nebulae, supernova, radio galaxies and quasars is presented. A brief glossary of terms is included. (UK)

  11. Efficient medium access control protocol for geostationary satellite systems

    Institute of Scientific and Technical Information of China (English)

    王丽娜; 顾学迈

    2004-01-01

    This paper proposes an efficient medium access control (MAC) protocol based on multifrequency-time division multiple access (MF-TDMA) for geostationary satellite systems deploying multiple spot-beams and onboard processing,which uses a method of random reservation access with movable boundaries to dynamically request the transmission slots and can transmit different types of traffic. The simulation results have shown that our designed MAC protocol can achieve a high bandwidth utilization, while providing the required quality of service (QoS) for each class of service.

  12. Bio-Inspired Energy-Aware Protocol Design for Cooperative Wireless Networks

    DEFF Research Database (Denmark)

    Perrucci, Gian Paolo; Anggraeni, Puri Novelti; Wardana, Satya Ardhy

    2011-01-01

    In this work, bio-inspired cooperation rules are applied to wireless communication networks. The main goal is to derive cooperative behaviour rules to improve the energy consumption of each mobile device. A medium access control (MAC) protocol particularly designed for peer-to-peer communication...... be achieved by this architecture using game theoretic approaches. As an extension, this work explores the impact of the MAC protocol on the power saving capabilities. This result shows that standard MAC mechanisms are not optimised for the considered cooperative setup. A new MAC protocol is proposed...... among cooperative wireless mobile devices is described. The work is based on a novel communication architecture, where a group of mobile devices are connected both to a cellular base station and among them using short-range communication links. A prior work has investigated the energy saving that can...

  13. Victor Bérard et la Macédoine

    Directory of Open Access Journals (Sweden)

    Ivan Savev

    2011-01-01

    Full Text Available Un helléniste convaincu, Victor Bérard, en vient, au début du XXe siècle à soutenir l’existence de « Macédoniens » et le slogan « la Macédoine aux Macédoniens”.Le Congrès de Berlin en 1878 avait laissé la Macédoine aux mains des Ottomans. La Grèce, la Serbie et la Bulgarie, parvenues à ses limites et prévoyant le retrait futur des Ottomans peaufinent les arguments linguistiques et historiques qui justifieront leurs revendications territoriales. Victor Bérard, un helléniste respecté et bon connaisseur de la région sud balkanique, effectue des enquêtes en Macédoine en 1896 et 1903 qu’il publie à Paris.Cette étude montre comment, dans le contexte de la propagande nationaliste des prétendants à la possession de la Macédoine, Victor Bérard en vient progressivement à affirmer qu’il existe une population autochtone, les Macédoniens. Il soutient leur programme pour la constitution d’une fédération ou confédération avec le slogan « la Macédoine aux Macédoniens » ce qui fait toute l’actualité de ses ouvrages.In 1878, the Congress of Berlin had left Macedonia in the hands of the Ottomans. Greece, Serbia and Bulgaria had reached its limits. Anticipating the Ottoman retreat, they polish language and historical arguments that will justify their territorial claims. Victor Bérard, a respected Hellenist and a good expert of the southern Balkans, is doing researches in Macedonia in 1896 and 1903. These will be later published in Paris.This study shows how, in the context of the nationalist propaganda build-up made by the candidates for the possession of Macedonia, Victor Bérard comes progressively to assert the existence of a native population: the Macedonians. He supports their program for the forming of a federation or confederation which slogan would be “Macedonia to Macedonians”. This makes his works very topical.

  14. MAC-Layer Active Dropping for Real-Time Video Streaming in 4G Access Networks

    KAUST Repository

    She, James

    2010-12-01

    This paper introduces a MAC-layer active dropping scheme to achieve effective resource utilization, which can satisfy the application-layer delay for real-time video streaming in time division multiple access based 4G broadband wireless access networks. When a video frame is not likely to be reconstructed within the application-layer delay bound at a receiver for the minimum decoding requirement, the MAC-layer protocol data units of such video frame will be proactively dropped before the transmission. An analytical model is developed to evaluate how confident a video frame can be delivered within its application-layer delay bound by jointly considering the effects of time-varying wireless channel, minimum decoding requirement of each video frame, data retransmission, and playback buffer. Extensive simulations with video traces are conducted to prove the effectiveness of the proposed scheme. When compared to conventional cross-layer schemes using prioritized-transmission/retransmission, the proposed scheme is practically implementable for more effective resource utilization, avoiding delay propagation, and achieving better video qualities under certain conditions.

  15. Noncooperative 802.11 MAC Layer Fingerprinting and Tracking of Mobile Devices

    Directory of Open Access Journals (Sweden)

    Pieter Robyns

    2017-01-01

    Full Text Available We present two novel noncooperative MAC layer fingerprinting and tracking techniques for Wi-Fi (802.11 enabled mobile devices. Our first technique demonstrates how a per-bit entropy analysis of a single captured frame allows an adversary to construct a fingerprint of the transmitter that is 80.0 to 67.6 percent unique for 50 to 100 observed devices and 33.0 to 15.1 percent unique for 1,000 to 10,000 observed devices. We show how existing mitigation strategies such as MAC address randomization can be circumvented using only this fingerprint and temporal information. Our second technique leverages peer-to-peer 802.11u Generic Advertisement Service (GAS requests and 802.11e Block Acknowledgement (BA requests to instigate transmissions on demand from devices that support these protocols. We validate these techniques using two datasets, one of which was recorded at a music festival containing 28,048 unique devices and the other at our research lab containing 138 unique devices. Finally, we discuss a number of countermeasures that can be put in place by mobile device vendors in order to prevent noncooperative tracking through the discussed techniques.

  16. Dolphin natures, human virtues: MacIntyre and ethical naturalism.

    Science.gov (United States)

    Glackin, Shane Nicholas

    2008-09-01

    Can biological facts explain human morality? Aristotelian 'virtue' ethics has traditionally assumed so. In recent years Alasdair MacIntyre has reintroduced a form of Aristotle's 'metaphysical biology' into his ethics. He argues that the ethological study of dependence and rationality in other species--dolphins in particular--sheds light on how those same traits in the typical lives of humans give rise to the moral virtues. However, some goal-oriented dolphin behaviour appears both dependent and rational in the precise manner which impresses MacIntyre, yet anything but ethically 'virtuous'. More damningly, dolphin ethologists consistently refuse to evaluate such behaviour in the manner MacIntyre claims is appropriate to moral judgement. In light of this, I argue that virtues--insofar as they name a biological or ethological category--do not name a morally significant one.

  17. Office for iPad and Mac for dummies

    CERN Document Server

    Weverka, Peter

    2015-01-01

    The easy way to work with Office on your iPad or Mac Are you a Mac user who isn't accustomed to working with Microsoft Office? Consider this friendly guide your go-to reference! Written in plain English and packed with easy-to-follow, step-by-step instructions, Office for iPad and Mac For Dummies walks you through every facet of Office, from installing the software and opening files to working with Word, Excel, PowerPoint, and Outlook-and beyond. Plus, you'll discover how to manage files, share content and collaborate online through social media, and find help when you need it. Two things a

  18. Activity Modelling and Comparative Evaluation of WSN MAC Security Attacks

    DEFF Research Database (Denmark)

    Pawar, Pranav M.; Nielsen, Rasmus Hjorth; Prasad, Neeli R.

    2012-01-01

    and initiate security attacks that disturb the normal functioning of the network in a severe manner. Such attacks affect the performance of the network by increasing the energy consumption, by reducing throughput and by inducing long delays. Of all existing WSN attacks, MAC layer attacks are considered...... the most harmful as they directly affect the available resources and thus the nodes’ energy consumption. The first endeavour of this paper is to model the activities of MAC layer security attacks to understand the flow of activities taking place when mounting the attack and when actually executing it....... The second aim of the paper is to simulate these attacks on hybrid MAC mechanisms, which shows the performance degradation of aWSN under the considered attacks. The modelling and implementation of the security attacks give an actual view of the network which can be useful in further investigating secure...

  19. The peculiar cluster MACS J0417.5-1154 in the C and X-bands

    Science.gov (United States)

    Sandhu, Pritpal; Malu, Siddharth; Raja, Ramij; Datta, Abhirup

    2018-06-01

    We present 5.5 and 9.0 GHz Australia Telescope Compact Array (ATCA) observations of the cluster MACSJ0417.5-1154, one of the most massive galaxy clusters and one of the brightest in X-ray in the Massive Cluster Survey (MACS). We estimate diffuse emission at 5.5 and 9.0 GHz from our ATCA observations, and compare the results with the 235 MHz and 610 MHz GMRT observations and 1575 MHz VLA observations. We also estimate the diffuse emission at low frequencies from existing GLEAM survey data (using the MWA telescope (http://www.mwatelescope.org)), and find that the steepening reported in earlier studies may have been an artefact of underestimates of diffuse emission at low frequencies. High-frequency radio observations of galaxy cluster mergers therefore provide an important complement to low-frequency observations, not only for a probing the `on' and `off' state of radio halos in these mergers, but also to constrain energetics of cluster mergers. We comment on the future directions that further studies of this cluster can take.

  20. Vehicle Health Management Communications Requirements for AeroMACS

    Science.gov (United States)

    Kerczewski, Robert J.; Clements, Donna J.; Apaza, Rafael D.

    2012-01-01

    As the development of standards for the aeronautical mobile airport communications system (AeroMACS) progresses, the process of identifying and quantifying appropriate uses for the system is progressing. In addition to defining important elements of AeroMACS standards, indentifying the systems uses impacts AeroMACS bandwidth requirements. Although an initial 59 MHz spectrum allocation for AeroMACS was established in 2007, the allocation may be inadequate; studies have indicated that 100 MHz or more of spectrum may be required to support airport surface communications. Hence additional spectrum allocations have been proposed. Vehicle health management (VHM) systems, which can produce large volumes of vehicle health data, were not considered in the original bandwidth requirements analyses, and are therefore of interest in supporting proposals for additional AeroMACS spectrum. VHM systems are an emerging development in air vehicle safety, and preliminary estimates of the amount of data that will be produced and transmitted off an aircraft, both in flight and on the ground, have been prepared based on estimates of data produced by on-board vehicle health sensors and initial concepts of data processing approaches. This allowed an initial estimate of VHM data transmission requirements for the airport surface. More recently, vehicle-level systems designed to process and analyze VHM data and draw conclusions on the current state of vehicle health have been undergoing testing and evaluation. These systems make use of vehicle system data that is mostly different from VHM data considered previously for airport surface transmission, and produce processed system outputs that will be also need to be archived, thus generating additional data load for AeroMACS. This paper provides an analysis of airport surface data transmission requirements resulting from the vehicle level reasoning systems, within the context of overall VHM data requirements.

  1. Mapping of MAC Address with Moving WiFi Scanner

    Directory of Open Access Journals (Sweden)

    Arief Hidayat

    2017-10-01

    Full Text Available Recently, Wifi is one of the most useful technologies that can be used for detecting and counting MAC Address. This paper described using of WiFi scanner which carried out seven times circulated the bus. The method used WiFi and GPS are to counting MAC address as raw data from the pedestrian smartphone, bus passenger or WiFi devices near from the bus as long as the bus going around the route. There are seven processes to make map WiFi data.

  2. MacVEE - the intimate Macintosh-VME system

    International Nuclear Information System (INIS)

    Taylor, B.G.

    1986-01-01

    The marriage of a mass-produced personal computer with the versatile VMEbus and CAMAC systems creates a cost-effective solution to many laboratory small system requirements. This paper describes MacVEE (Microcomputer Applied to the Control of VME Electronic Equipment), a novel system in which an Apple Macintosh computer is equipped with a special interface which allows it direct memory-mapped access to single or multiple VME and CAMAC crates interconnected by a ribbon cable bus. The bus is driven by an electronics plinth called MacPlinth, which attaches to the computer and becomes an integral part of it. (Auth.)

  3. MacIntyre's Moral Theory and Moral Relativism

    OpenAIRE

    Ali Abedi Renani

    2017-01-01

    In this paper, I seek to explain the similarity and disparity between MacIntyre’s moral theory and moral relativism. I will argue that MacIntyre’s moral theory can escape the charge of moral relativism because both his earlier social and his later metaphysical approaches appeal to some criteria, the human telos or universal human qualities respectively. The notion of telos is wider than the notion of function which is defined in social contexts. If there is a context-transcending notion of te...

  4. God, Sport Philosophy, Kinesiology: A MacIntyrean Examination

    Science.gov (United States)

    Twietmeyer, Gregg

    2015-01-01

    Sport philosophy is in crisis. This subdiscipline of kinesiology garners little to no respect and few tenure track lines in kinesiology departments. Why is this the case? Why isn't philosophy held in greater esteem? Is it possible that philosopher Alasdair MacIntyre's (2009) diagnosis found in "God, Philosophy, Universities" could…

  5. Florence Jessie MacWilliams (1917-1990)

    Indian Academy of Sciences (India)

    famous mathematician Oscar Zariski, well known for his work in algebraic geometry, at. Johns Hopkins University, following him to Harvard University to study with him for a year. There was a break in her studies for many years following her marriage in 1941 to. W al ter Mac Williams, an engineer, and the birth and raising of ...

  6. Evaluation of the MacDonald scabbler for highway use.

    Science.gov (United States)

    1975-01-01

    The MacDonald Scabbler is a small, hand held machine suitable for use in cleaning and roughening concrete surfaces, It weighs 308 pounds (140 kg), has 11 cutting heads, and, as a power source, requires a compressor capable of delivering 365 cubic foo...

  7. Integrated, Kerberized Login on MacOS X

    Science.gov (United States)

    Hotz, Henry B.

    2006-01-01

    Context for this information. MacOS X login process and available hooks. Authorization Services configuration. Authorization Services plug-in s. Kerberos plug-in s. Other bugs and recommendations. Authorization Services Called by loginwindow, screen saver and fast user switching. It calls Directory Services, Login Hook, and Login Items (System Preferences).

  8. Increasing the permeability of Escherichia coli using MAC13243

    DEFF Research Database (Denmark)

    Muheim, Claudio; Götzke, Hansjörg; Eriksson, Anna U.

    2017-01-01

    molecules that make the outer membrane of Escherichia coli more permeable. We identified MAC13243, an inhibitor of the periplasmic chaperone LolA that traffics lipoproteins from the inner to the outer membrane. We observed that cells were (1) more permeable to the fluorescent probe 1-N...

  9. Mechatronical Aided Concept (MAC in Intelligent Transport Vehicles Design

    Directory of Open Access Journals (Sweden)

    Pavel Pavlasek

    2003-01-01

    Full Text Available This article deals with the principles of synergy effect of mechatronical aided concept (MAC to the design of intelligent transport vehicles products applying CA technologies and virtual reality design methods. Also includes presentation of intelligent railway vehicle development.

  10. MAC mini acceptance test procedures, software Version 3.3

    International Nuclear Information System (INIS)

    Russell, V.K.

    1994-01-01

    The K Basins Materials Accounting (MAC) programs had some improvements made to it to to change slightly the access authorized users had to the modification of critical data. This ATP describes how the code was to be tested to verify its correctness

  11. Cognitive Communications Protocols for SATCOM

    Science.gov (United States)

    2017-10-20

    communications protocols for satellite and space communications with possible broad applications in defense, homeland-security as well as consumer ...communications with possible broad applications in defense, homeland-security, and civilian as well as consumer telecommunications. Such cognitive...vulnerable against smart jammers that may attempt to learn the cognitive radios own behavior . In response, our second class of proposed algorithms

  12. Impact of Radio Link Unreliability on the Connectivity of Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Gorce Jean-Marie

    2007-01-01

    Full Text Available Many works have been devoted to connectivity of ad hoc networks. This is an important feature for wireless sensor networks (WSNs to provide the nodes with the capability of communicating with one or several sinks. In most of these works, radio links are assumed ideal, that is, with no transmission errors. To fulfil this assumption, the reception threshold should be high enough to guarantee that radio links have a low transmission error probability. As a consequence, all unreliable links are dismissed. This approach is suboptimal concerning energy consumption because unreliable links should permit to reduce either the transmission power or the number of active nodes. The aim of this paper is to quantify the contribution of unreliable long hops to an increase of the connectivity of WSNs. In our model, each node is assumed to be connected to each other node in a probabilistic manner. Such a network is modeled as a complete random graph, that is, all edges exist. The instantaneous node degree is then defined as the number of simultaneous valid single-hop receptions of the same message, and finally the mean node degree is computed analytically in both AWGN and block-fading channels. We show the impact on connectivity of two MACs and routing parameters. The first one is the energy detection level such as the one used in carrier sense mechanisms. The second one is the reliability threshold used by the routing layer to select stable links only. Both analytic and simulation results show that using opportunistic protocols is challenging.

  13. Impact of Radio Link Unreliability on the Connectivity of Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Jean-Marie Gorce

    2007-06-01

    Full Text Available Many works have been devoted to connectivity of ad hoc networks. This is an important feature for wireless sensor networks (WSNs to provide the nodes with the capability of communicating with one or several sinks. In most of these works, radio links are assumed ideal, that is, with no transmission errors. To fulfil this assumption, the reception threshold should be high enough to guarantee that radio links have a low transmission error probability. As a consequence, all unreliable links are dismissed. This approach is suboptimal concerning energy consumption because unreliable links should permit to reduce either the transmission power or the number of active nodes. The aim of this paper is to quantify the contribution of unreliable long hops to an increase of the connectivity of WSNs. In our model, each node is assumed to be connected to each other node in a probabilistic manner. Such a network is modeled as a complete random graph, that is, all edges exist. The instantaneous node degree is then defined as the number of simultaneous valid single-hop receptions of the same message, and finally the mean node degree is computed analytically in both AWGN and block-fading channels. We show the impact on connectivity of two MACs and routing parameters. The first one is the energy detection level such as the one used in carrier sense mechanisms. The second one is the reliability threshold used by the routing layer to select stable links only. Both analytic and simulation results show that using opportunistic protocols is challenging.

  14. Improving broadcast performance of radio duty-cycled Internet-of-Things devices

    NARCIS (Netherlands)

    Guclu, S.S.; Özcelebi, T.; Lukkien, J.J.

    2017-01-01

    Asynchronous Radio Duty Cycling (ARDC) protocols can make embedded networked devices more energy efficient by keeping their radio off most of the time without a need for synchronization between devices. Some ARDC protocols can operate under 6LoWPAN adaptation layer in order to enable the vision of

  15. dynamic-threshold-limited timed-token (dtltt) protocol

    African Journals Online (AJOL)

    2013-03-01

    Mar 1, 2013 ... Token (STOGSTT) Media Access Control (MAC) protocol for channel capacity allocation to the asynchronous traffic in ... Keywords: multi-access, multiservice, network, synchronous, asynchronous, traffic, timed-token. 1. Introduction .... Messages generated in the system at run time may be classified as ...

  16. Library Signage: Applications for the Apple Macintosh and MacPaint.

    Science.gov (United States)

    Diskin, Jill A.; FitzGerald, Patricia

    1984-01-01

    Describes specific applications of the Macintosh computer at Carnegie-Mellon University Libraries, where MacPaint was used as a flexible, easy to use, and powerful tool to produce informational, instructional, and promotional signage. Profiles of system hardware and software, an evaluation of the computer program MacPaint, and MacPaint signage…

  17. Teaching a Classic for All Ages: Fairy Tales and Stories of George MacDonald.

    Science.gov (United States)

    Sadler, Glenn Edward

    1995-01-01

    Discusses the life and writings of George MacDonald (1824-1905). Suggests that the most striking feature of MacDonald's children's books is his sensitivity toward spiritual values and the power of change within the lives of his characters. Appends a list of questions to stimulate student response to MacDonald's writings. (RS)

  18. Ad hoc mobile wireless networks principles, protocols, and applications

    CERN Document Server

    Sarkar, Subir Kumar

    2013-01-01

    The military, the research community, emergency services, and industrial environments all rely on ad hoc mobile wireless networks because of their simple infrastructure and minimal central administration. Now in its second edition, Ad Hoc Mobile Wireless Networks: Principles, Protocols, and Applications explains the concepts, mechanism, design, and performance of these highly valued systems. Following an overview of wireless network fundamentals, the book explores MAC layer, routing, multicast, and transport layer protocols for ad hoc mobile wireless networks. Next, it examines quality of serv

  19. Detecting MAC Spoofing Attacks in 802.11 Networks through Fingerprinting on the MAC Layer

    OpenAIRE

    Idland, Christer

    2011-01-01

    In order to provide hassle-free connection options many wireless local area network (WLAN) providers choose to have their networks completely open. In other words there is no password required in order to connect. Such open configurations do not provide any security features on the wireless medium, but are often implemented with other solutions as captive portals. A captive portal forces a Hypertext Transfer Protocol (HTTP) client to see a certain webpage, usually for authentication purposes....

  20. Impact of cognitive radio on radio astronomy

    NARCIS (Netherlands)

    Bentum, Marinus Jan; Boonstra, A.J.; Baan, W.A.

    2010-01-01

    The introduction of new communication techniques requires an increase in the efficiency of spectrum usage. Cognitive radio is one of the new techniques that fosters spectrum efficiency by using unoccupied frequency spectrum for communications. However, cognitive radio will increase the transmission

  1. Una lectura interpretativa de Tras la virtud, de Alasdair MacIntyre - An Interpretive Reading of After Virtue, by Alasdair MacIntyre

    Directory of Open Access Journals (Sweden)

    Fernando Fernández-Llebrez

    2010-12-01

    Full Text Available This article centers on the thought of Alasdair MacIntyre, whose most prominente work, After Virtue, is considered a classic of political science. In contrast with other reviews, this article will examine After Virtue within the broader context of MacIntyre’s thinking and publications. An overview of MacIntyre’s literary corpus and the evolution of his thinking will shed light on the volume examined and trace certain ideas that are characteristic of this Scottish political philosopher. Matters that remained unsettled in After Virtue have become over time more defined in MacIntyre’s thinking, such as the influence exerted upon him by Thomas Aquinas.

  2. Fast Radio Bursts

    Indian Academy of Sciences (India)

    Akshaya Rane

    2017-09-12

    ) which were first discovered a decade ago. Following an introduction to radio transients in general, including pulsars and rotating radio transients, we discuss the discovery of FRBs. We then discuss FRB follow-up ...

  3. Mac OS X Snow Leopard for Power Users Advanced Capabilities and Techniques

    CERN Document Server

    Granneman, Scott

    2010-01-01

    Mac OS X Snow Leopard for Power Users: Advanced Capabilities and Techniques is for Mac OS X users who want to go beyond the obvious, the standard, and the easy. If want to dig deeper into Mac OS X and maximize your skills and productivity using the world's slickest and most elegant operating system, then this is the book for you. Written by Scott Granneman, an experienced teacher, developer, and consultant, Mac OS X for Power Users helps you push Mac OS X to the max, unveiling advanced techniques and options that you may have not known even existed. Create custom workflows and apps with Automa

  4. Virtual observatory tools and amateur radio observations supporting scientific analysis of Jupiter radio emissions

    Science.gov (United States)

    Cecconi, Baptiste; Hess, Sebastien; Le Sidaner, Pierre; Savalle, Renaud; Stéphane, Erard; Coffre, Andrée; Thétas, Emmanuel; André, Nicolas; Génot, Vincent; Thieman, Jim; Typinski, Dave; Sky, Jim; Higgins, Chuck; Imai, Masafumi

    2016-04-01

    In the frame of the preparation of the NASA/JUNO and ESA/JUICE (Jupiter Icy Moon Explorer) missions, and the development of a planetary sciences virtual observatory (VO), we are proposing a new set of tools directed to data providers as well as users, in order to ease data sharing and discovery. We will focus on ground based planetary radio observations (thus mainly Jupiter radio emissions), trying for instance to enhance the temporal coverage of jovian decametric emission. The data service we will be using is EPN-TAP, a planetary science data access protocol developed by Europlanet-VESPA (Virtual European Solar and Planetary Access). This protocol is derived from IVOA (International Virtual Observatory Alliance) standards. The Jupiter Routine Observations from the Nancay Decameter Array are already shared on the planetary science VO using this protocol, as well as data from the Iitate Low Frquency Radio Antenna, in Japan. Amateur radio data from the RadioJOVE project is also available. The attached figure shows data from those three providers. We will first introduce the VO tools and concepts of interest for the planetary radioastronomy community. We will then present the various data formats now used for such data services, as well as their associated metadata. We will finally show various prototypical tools that make use of this shared datasets.

  5. La radio digital

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Cortés S.

    2015-01-01

    Full Text Available La radio digital es un producto de la llamada convergencia digital. Las nuevas tecnologías interconectadas permiten la aparición de nuevos modos de audiencia y la implementación de herramientas versátiles. Habla del problema de los estándares, de la radio satelital, la radio digital terrestre, las radios internacionales, la interactividad.

  6. Affordability of cataract surgery using the Big Mac prices

    OpenAIRE

    Van C. Lansingh; Marissa J. Carter; Kristen A. Eckert; Kevin L. Winthrop; João M. Furtado; Serge Resnikoff

    2015-01-01

    Purpose: One barrier to cataract surgery is its high price in some countries. This study aims to understand to what extent the price of cataract surgery is over- or undervalued and whether it varies in relation to GDP using The Economist newspaper Big Mac Index (BMcI) methodology, which measures the purchasing power parity between different currencies. Methods: Peer-reviewed articles containing information on cataract surgery prices were searched from 1993 to June 2012 in databases. Ophtha...

  7. ITER management advisory committee (MAC) meeting in Naka

    International Nuclear Information System (INIS)

    Yoshikawa, M.

    2000-01-01

    The ITER Management Advisory Committee (MAC) Meeting was held on 28 June 2000 in Moskow, Russia. The main topics were the consideration of the report by the director on the ITER EDA status, the review of the work program, the review of the joint fund, the review of a schedule of ITER meetings and initial discussion and consideration on the disposition of R and D hardware and facilities and other dispositions relating to the termination of the EDA

  8. LHC@home online tutorial for Mac users - recording

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    A step-by-step online tutorial about LHC@home for Mac users by Alexandre Racine. It contains detailed instructions on how-to-join this volunteer computing project.  There are 3 screen capture videos with the real installation process accelerated attached to the event page. This 5' video is linked from http://lhcathome.web.cern.ch/join-us Also from the CDS e-learning category.

  9. Commercial Radio as Communication.

    Science.gov (United States)

    Rothenbuhler, Eric W.

    1996-01-01

    Compares the day-to-day work routines of commercial radio with the principles of a theoretical communication model. Illuminates peculiarities of the conduct of communication by commercial radio. Discusses the application of theoretical models to the evaluation of practicing institutions. Offers assessments of commercial radio deriving from…

  10. MacWilliams Identity for M-Spotty Weight Enumerator

    Science.gov (United States)

    Suzuki, Kazuyoshi; Fujiwara, Eiji

    M-spotty byte error control codes are very effective for correcting/detecting errors in semiconductor memory systems that employ recent high-density RAM chips with wide I/O data (e.g., 8, 16, or 32bits). In this case, the width of the I/O data is one byte. A spotty byte error is defined as random t-bit errors within a byte of length b bits, where 1 le t ≤ b. Then, an error is called an m-spotty byte error if at least one spotty byte error is present in a byte. M-spotty byte error control codes are characterized by the m-spotty distance, which includes the Hamming distance as a special case for t =1 or t = b. The MacWilliams identity provides the relationship between the weight distribution of a code and that of its dual code. The present paper presents the MacWilliams identity for the m-spotty weight enumerator of m-spotty byte error control codes. In addition, the present paper clarifies that the indicated identity includes the MacWilliams identity for the Hamming weight enumerator as a special case.

  11. Bioremediation protocols

    National Research Council Canada - National Science Library

    Sheehan, David

    1997-01-01

    ..., .. . . . . .. ,. . . .. . . . . . . . .. . . . . .. . . .. . .. 3 2 Granular Nina Sludge Christiansen, Consortia lndra for Bioremediation, M. Mathrani, and Birgitte K. Ahring . 23 PART II PROTOCOLS...

  12. Ham radio for dummies

    CERN Document Server

    Silver, H Ward

    2013-01-01

    An ideal first step for learning about ham radio Beyond operating wirelessly, today's ham radio operators can transmit data and pictures; use the Internet, laser, and microwave transmitters; and travel to places high and low to make contact. This hands-on beginner guide reflects the operational and technical changes to amateur radio over the past decade and provides you with updated licensing requirements and information, changes in digital communication (such as the Internet, social media, and GPS), and how to use e-mail via radio. Addresses the critical use of ham radio for replacing downe

  13. Radiography of Spanish Radio

    Directory of Open Access Journals (Sweden)

    Dra. Emma Rodero Antón

    2007-01-01

    Full Text Available In its eighty years of existence, radio has been always characterized to adapt to the social, cultural and technological transformations. Thus it has been until this moment. Nevertheless, some years ago, the authors and professionals of this medium have been detecting a stagnation that affects to its structure. At a time in continuous technological evolution, radio demands a deep transformation. For that reason, from the conviction of which the future radio, public and commercial, will necessarily have to renew itself, in this paper we establish ten problems and their possible solutions to the radio crisis in order to draw an x-ray of radio in Spain. Radio has future, but it is necessary to work actively by it. That the radio continues being part of sound of our life, it will depend on the work of all: companies, advertisers, professionals, students, investigators and listeners.

  14. MacA, a periplasmic membrane fusion protein of the macrolide transporter MacAB-TolC, binds lipopolysaccharide core specifically and with high affinity.

    Science.gov (United States)

    Lu, Shuo; Zgurskaya, Helen I

    2013-11-01

    The Escherichia coli MacAB-TolC transporter has been implicated in efflux of macrolide antibiotics and secretion of enterotoxin STII. In this study, we found that purified MacA, a periplasmic membrane fusion protein, contains one tightly bound rough core lipopolysaccharide (R-LPS) molecule per MacA molecule. R-LPS was bound specifically to MacA protein with affinity exceeding that of polymyxin B. Sequence analyses showed that MacA contains two high-density clusters of positively charged amino acid residues located in the cytoplasmic N-terminal domain and the periplasmic C-terminal domain. Substitutions in the C-terminal cluster reducing the positive-charge density completely abolished binding of R-LPS. At the same time, these substitutions significantly reduced the functionality of MacA in the protection of E. coli against macrolides in vivo and in the in vitro MacB ATPase stimulation assays. Taken together, our results suggest that R-LPS or a similar glycolipid is a physiological substrate of MacAB-TolC.

  15. Energy Efficient Medium Access Control Protocol for Clustered Wireless Sensor Networks with Adaptive Cross-Layer Scheduling.

    Science.gov (United States)

    Sefuba, Maria; Walingo, Tom; Takawira, Fambirai

    2015-09-18

    This paper presents an Energy Efficient Medium Access Control (MAC) protocol for clustered wireless sensor networks that aims to improve energy efficiency and delay performance. The proposed protocol employs an adaptive cross-layer intra-cluster scheduling and an inter-cluster relay selection diversity. The scheduling is based on available data packets and remaining energy level of the source node (SN). This helps to minimize idle listening on nodes without data to transmit as well as reducing control packet overhead. The relay selection diversity is carried out between clusters, by the cluster head (CH), and the base station (BS). The diversity helps to improve network reliability and prolong the network lifetime. Relay selection is determined based on the communication distance, the remaining energy and the channel quality indicator (CQI) for the relay cluster head (RCH). An analytical framework for energy consumption and transmission delay for the proposed MAC protocol is presented in this work. The performance of the proposed MAC protocol is evaluated based on transmission delay, energy consumption, and network lifetime. The results obtained indicate that the proposed MAC protocol provides improved performance than traditional cluster based MAC protocols.

  16. MC-LMAC: A Multi-Channel MAC Protocol for Wireless Sensor Networks

    NARCIS (Netherlands)

    Durmaz, O.; Jansen, P.G.; Mullender, Sape J.

    2008-01-01

    In traditional wireless sensor network (WSN) applications, energy efficiency is considered to be the most important concern whereas utilizing the use of bandwidth and maximizing the throughput are of secondary importance. However, recent applications, such as structural health monitoring, require

  17. Mac configuration management at the Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Marcus, Allan B [Los Alamos National Laboratory

    2010-01-01

    The Los Alamos National Laboratory (LANL) had a need for central configuration management of non-Windows computers. LANL has three to five thousand Macs and an equal number of Linux based systems. The primary goal was to be able to inventory all non-windows systems and patch Mc OS X systems. LANL examined a number of commercial and open source solutions and ultimately selected Puppet. This paper will discuss why we chose Puppet, how we implemented it, and some lessons we learned along the way.

  18. An Optimized Virtual Scheme for Reducing Collisions in MAC Layer

    OpenAIRE

    M. Sivakumar; S. Saravanan

    2015-01-01

    The main function of Medium Access Control (MAC) is to share the channel efficiently between all nodes. In the real-time scenario, there will be certain amount of wastage in bandwidth due to back-off periods. More bandwidth will be wasted in idle state if the back-off period is very high and collision may occur if the back-off period is small. So, an optimization is needed for this problem. The main objective of the work is to reduce delay due to back-off period thereby reducing collision and...

  19. MAC/FAC: A Model of Similarity-Based Retrieval

    Science.gov (United States)

    1994-10-01

    Grapes (0.28) 327 Sour Grapes, analog The Taming of the Shrew (0.22), Merry Wives 251 (0.18), S[11 stories], Sour Grapes (-0.19) Sour Grapes, literal... The Institute for the 0 1 Learning Sciences Northwestern University CD• 00 MAC/FAC: A MODEL OF SIMILARITY-BASED RETRIEVAL Kenneth D. Forbus Dedre...Gentner Keith Law Technical Report #59 • October 1994 94-35188 wit Establisthed in 1989 with the support of Andersen Consulting Form Approved REPORT

  20. Planeamiento Estratégico para Rímac Seguros

    OpenAIRE

    Alvitez Muñoz, Julio César; Esquivel Porras, César Augusto; Slocovich Salcedo, Erick Rodolfo

    2005-01-01

    El presente trabajo desarrolla una propuesta de valor en el ámbito del mercado de seguros de vida para ser implementada en Rímac Seguros, permitiendo asegurar a la empresa la sostenibilidad de su liderazgo a través del incremento de su participación en el mercado y la fidelización de sus clientes. Las condiciones en las que se desarrolla la industria de seguros en el mundo y en el Perú en particular, como la séptima en volumen de primas a nivel latinoamericano ofrece un mercado reducido ba...

  1. Senior radio listeners

    DEFF Research Database (Denmark)

    Blaakilde, Anne Leonora

    Radiobroadcasting and the hardware materialization of radio have during the 20th century changed significantly, which means that senior radio listeners have travelled along with this evolution from large, impressive radio furnitures to DAB and small, wireless, mobile devices, and from grave...... and solemn radio voices to lightharted, laughing and chatting speakers. Senior radio listerners have experienced the development and refinements of technique, content and genres. It is now expected of all media users that they are capable of crossing media, combining, juggling and jumping between various...... media platforms, not the least when listening to radio. The elder generation is no exception from this. Recently, for instance, the Danish public broadcast DR has carried out an exodus of programmes targeted for the senior segment. These programmes are removed from regular FM and sent to DAB receivers...

  2. Broadcast design in cognitive radio ad hoc networks

    CERN Document Server

    Song, Yi

    2014-01-01

    This SpringerBrief investigates the special challenges of broadcast design in cognitive radio (CR) ad hoc networks. It introduces two broadcast protocols in CR ad hoc networks: a quality-of-service based broadcast protocol under blind information and a fully-distributed broadcast protocol with collision avoidance. A novel unified analytical model is also presented to analyze the performance of the broadcast protocols. This is the first book dedicated to the unique broadcast design challenges in CR ad hoc networks. The authors also discuss the recent research on the performance analysis of broa

  3. Learning Microsoft Excel 2011 for Mac video training DVD

    CERN Document Server

    Vaccaro, Guy

    2011-01-01

    In this video tutorial for Microsoft Excel 2011 For Mac, expert author Guy Vaccaro teaches you to effectively utilize the features and functions of Excel through project based learning. You will complete various projects, and along they way learn to leverage the power of the most important features Excel 2011 has to offer the Mac user. Starting your training course with the creation of a spreadsheet to record and monitor sales data, you will learn the basics of what you can do with a spreadsheet. You will then move on to creating a Profit and Loss report, learning formulas along the way. Moving to score sheets for a sports day, you will discover conditional based formatting, lookups, and more. You then create a functional expense claim form, advancing your Excel expertise. Moving on to a sales contact management sheet, you will discover how you can manipulate text, and even create mail merges from Excel. Finally, you will utilize all your knowledge thus far to create a sales report, including charts, pivot ta...

  4. Design of ultra-low power impulse radios

    CERN Document Server

    Apsel, Alyssa; Dokania, Rajeev

    2014-01-01

    This book covers the fundamental principles behind the design of ultra-low power radios and how they can form networks to facilitate a variety of applications within healthcare and environmental monitoring, since they may operate for years off a small battery or even harvest energy from the environment. These radios are distinct from conventional radios in that they must operate with very constrained resources and low overhead.  This book provides a thorough discussion of the challenges associated with designing radios with such constrained resources, as well as fundamental design concepts and practical approaches to implementing working designs.  Coverage includes integrated circuit design, timing and control considerations, fundamental theory behind low power and time domain operation, and network/communication protocol considerations.   • Enables detailed understanding of the design space for ultra-low power radio; • Provides detailed discussion and examples of the design of a practical low power ...

  5. C-MAC compared with direct laryngoscopy for intubation in patients with cervical spine immobilization: A manikin trial.

    Science.gov (United States)

    Smereka, Jacek; Ladny, Jerzy R; Naylor, Amanda; Ruetzler, Kurt; Szarpak, Lukasz

    2017-08-01

    The aim of this study was to compare C-MAC videolaryngoscopy with direct laryngoscopy for intubation in simulated cervical spine immobilization conditions. The study was designed as a prospective randomized crossover manikin trial. 70 paramedics with immobilization (Scenario A); manual inline cervical immobilization (Scenario B); cervical immobilization using cervical extraction collar (Scenario C). Scenario A: Nearly all participants performed successful intubations with both MAC and C-MAC on the first attempt (95.7% MAC vs. 100% C-MAC), with similar intubation times (16.5s MAC vs. 18s C-MAC). Scenario B: The results with C-MAC were significantly better than those with MAC (pimmobilization. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Uticaj transportnih protokola na efikasnost namenskih radio-komunikacija

    Directory of Open Access Journals (Sweden)

    Ljubiša S. Nedeljković

    2014-04-01

    Full Text Available Savremene namenske radio-komunikacije zasnivaju se na internet protokolu. Efikasnost namenskih radio-komunikacija zavisi od propusnosti. Na propusnost namenskih radio-komunikacija utiču i transportni protokoli. U radu je analizirana propusnost transportnih protokola TCP (Transport Control Protocol i UDP (User Datagram Protocol u VF (visoko frekvencijskim i VVF (vrlo visoko- frekvencijskim namenskim radio-komunikacijama sa očekivanim vremenima kašnjenja i verovatnoćom greške po paketu podataka. Ocenjena je mogućnost njihove primene u namenskim radio-komunikacijama. Pri tome je uzet u obzir uticaj sledećih faktora: vreme povratnog puta, veličina paketa podataka, veličina prozora i verovatnoća greške po paketu podataka. Transportni protokol sa većom propusnošću pogodniji je za primenu u namenskim radio-komunikacijama. Veća propusnost transportnih protokola znači da je veća i propusnost namenskih radio-komunikacija. 

  7. Ionosphere and Radio Communication

    Indian Academy of Sciences (India)

    The upperionosphere is used for radio communication and navigationas it reflects long, medium, as well as short radio waves. Sincesolar radiation is the main cause of the existence of ionosphere,any variation in the radiations can affect the entireradio communication system. This article attempts to brieflyintroduce the ...

  8. Writing for Radio.

    Science.gov (United States)

    Tupper, Marianna S.

    1995-01-01

    Describes a 24-hour commercial radio station simulation class project for eighth-grade language arts. Students wrote their own scripts, chose music and were disc jockeys on their own music and talk shows, and prepared news and traffic reports. Guest speakers from actual commercial radio came in to discuss issues such as advertising, censorship,…

  9. Valuing commercial radio licences

    NARCIS (Netherlands)

    Kerste, M.; Poort, J.; van Eijk, N.

    2015-01-01

    Within the EU regulatory framework, licensees for commercial radio broadcasting may be charged a fee to ensure optimal allocation of scarce resources but not to maximize public revenues. While radio licence renewal occurs in many EU countries, an objective, model-based approach for setting licence

  10. The Radio Jove Project

    Science.gov (United States)

    Thieman, J. R.

    2010-01-01

    The Radio love Project is a hands-on education and outreach project in which students, or any other interested individuals or groups build a radio telescope from a kit, operate the radio telescope, transmit the resulting signals through the internet if desired, analyze the results, and share the results with others through archives or general discussions among the observers. Radio love is intended to provide an introduction to radio astronomy for the observer. The equipment allows the user to observe radio signals from Jupiter, the Sun, the galaxy, and Earth-based radiation both natural and man-made. The project was started through a NASA Director's Discretionary Fund grant more than ten years ago. it has continued to be carried out through the dedicated efforts of a group of mainly volunteers. Dearly 1500 kits have been distributed throughout the world. Participation can also be done without building a kit. Pre-built kits are available. Users can also monitor remote radio telescopes through the internet using free downloadable software available through the radiosky.com website. There have been many stories of prize-winning projects, inspirational results, collaborative efforts, etc. We continue to build the community of observers and are always open to new thoughts about how to inspire the observers to still greater involvement in the science and technology associated with Radio Jove.

  11. Boom Booom Net Radio

    DEFF Research Database (Denmark)

    Grimshaw, Mark Nicholas; Yong, Louisa; Dobie, Ian

    1999-01-01

    of an existing Internet radio station; Boom Booom Net Radio. Whilst necessity dictates some use of technology-related terminology, wherever possible we have endeavoured to keep such jargon to a minimum and to either explain it in the text or to provide further explanation in the appended glossary....

  12. TMAC: Timestamp-Ordered MAC for CSMA/CA Wireless Mesh Networks

    KAUST Repository

    Nawab, Faisal Saud Yousef

    2011-07-31

    We propose TMAC, a timestamp-ordered MAC protocol for Wireless Mesh Networks (WMNs). TMAC extends CSMA/CA by scheduling data packets based on their age. Prior to transmitting a data packet, a transmitter broadcasts a request control message appended with a timestamp to a selected list of neighbors. It can proceed with the transmission only if it receives a sufficient number of grant control messages from these neighbors. A grant message indicates that the associated data packet has the lowest timestamp of all the packets pending transmission at the local transmit queue. We demonstrate that a loose ordering of timestamps among neighboring nodes is sufficient for enforcing local fairness, subsequently leading to flow rate fairness in a multi-hop WMN. We show that TMAC can be implemented using the control frames in IEEE 802.11 stack, and thus can be easily integrated in existing 802.11-based WMNs. Our simulation results show that TMAC achieves excellent resource allocation fairness while maintaining over 90% of maximum link capacity in parking lot and large grid topologies.

  13. Achievable Throughput-Based MAC Layer Handoff in IEEE 802.11 Wireless Local Area Networks

    Directory of Open Access Journals (Sweden)

    Wu Haitao

    2009-01-01

    Full Text Available We propose a MAC layer handoff mechanism for IEEE 802.11 Wireless Local Area Networks (WLAN to give benefit to bandwidth-greedy applications at STAs. The proposed mechanism determines an optimal AP with the maximum achievable throughput rather than the best signal condition by estimating the AP's bandwidth with a new on-the-fly measurement method, Transient Frame Capture (TFC, and predicting the actual throughput could be achieved at STAs. Since the TFC is employed based on the promiscuous mode of WLAN NIC, STAs can avoid the service degradation through the current associated AP. In addition, the proposed mechanism is a client-only solution which does not require any modification of network protocol on APs. To evaluate the performance of the proposed mechanism, we develop an analytic model to estimate reliable and accurate bandwidth of the AP and demonstrate through testbed measurement with various experimental study methods. We also validate the fairness of the proposed mechanism through simulation studies.

  14. Accuracy of the MacArthur competence assessment tool for clinical research (MacCAT-CR) for measuring children's competence to consent to clinical research.

    Science.gov (United States)

    Hein, Irma M; Troost, Pieter W; Lindeboom, Robert; Benninga, Marc A; Zwaan, C Michel; van Goudoever, Johannes B; Lindauer, Ramón J L

    2014-12-01

    An objective assessment of children's competence to consent to research participation is currently not possible. Age limits for asking children's consent vary considerably between countries, and, to our knowledge, the correlation between competence and children's age has never been systematically investigated. To test a standardized competence assessment instrument for children by modifying the MacArthur Competence Assessment Tool for Clinical Research (MacCAT-CR), to investigate its reliability and validity, and to examine the correlation of its assessment with age and estimate cutoff ages. This prospective study included children and adolescents aged 6 to 18 years in the inpatient and outpatient departments of allergology, gastroenterology, oncology, ophthalmology, and pulmonology from January 1, 2012, through January 1, 2014. Participants were eligible for clinical research studies, including observational studies and randomized clinical trials. Competence judgments by experts aware of the 4 relevant criteria-understanding, appreciation, reasoning, and choice-were used to establish the reference standard. The index test was the MacCAT-CR, which used a semistructured interview format. Interrater reliability, validity, and dimensionality of the MacCAT-CR and estimated cutoff ages for competence. Of 209 eligible patients, we included 161 (mean age, 10.6 years; 47.2% male). Good reproducibility of MacCAT-CR total and subscale scores was observed (intraclass correlation coefficient range, 0.68-0.92). We confirmed unidimensionality of the MacCAT-CR. By the reference standard, we judged 54 children (33.5%) to be incompetent; by the MacCAT-CR, 61 children (37.9%). Criterion-related validity of MacCAT-CR scores was supported by high overall accuracy in correctly classifying children as competent against the reference standard (area under the receiver operating characteristics curve, 0.78). Age was a good predictor of competence on the MacCAT-CR (area under the receiver

  15. Antimoulting Activity of Eremanthus erythropappus (DC. MacLeisch

    Directory of Open Access Journals (Sweden)

    Danielle Barbosa

    2012-06-01

    Resumo. Os extratos e metabólitos secundários de plantas podem agir como agentes tóxicos e inibidores do da alimentação e do desenvolvimento em insetos. Neste estudo foi utilizado Oncopeltus fasciatus (Dallas (Hemiptera como modelo experimental a fim de avaliar as atividades do extrato etanólico bruto e frações obtidos das flores ou caules de Eremanthus erythropappus (DC. MacLeisch (Asteraceae, na mortalidade e sobre o desenvolvimento do inseto. A fração butanólica obtida do extrato etanólico mostrou toxidade sobre as ninfas de O. fasciatus, bem como atividade de inibição do crescimento. Os resultados sugerem que a fração butanólica de E. erythropappus possui substâncias ativas sobre a fisiologia, crescimento e desenvolvimento de insetos.

  16. The Virtues of Scientific Practice: MacIntyre,

    Science.gov (United States)

    Hicks, Daniel J; Stapleford, Thomas A

    2016-09-01

    “Practice” has become a ubiquitous term in the history of science, and yet historians have not always reflected on its philosophical import and in particular on its potential connections with ethics. This essay draws on the work of the virtue ethicist Alasdair MacIntyre to develop a theory of “communal practices” and explore how such an approach can inform the history of science, including allegations about the corruption of science by wealth or power, consideration of scientific ethics or “moral economies,” the role of values in science, the ethical distinctiveness (or not) of scientific vocations, and the relationship between history of science and the practice of science itself.

  17. Rocket measurements of electron density irregularities during MAC/SINE

    Science.gov (United States)

    Ulwick, J. C.

    1989-01-01

    Four Super Arcas rockets were launched at the Andoya Rocket Range, Norway, as part of the MAC/SINE campaign to measure electron density irregularities with high spatial resolution in the cold summer polar mesosphere. They were launched as part of two salvos: the turbulent/gravity wave salvo (3 rockets) and the EISCAT/SOUSY radar salvo (one rocket). In both salvos meteorological rockets, measuring temperature and winds, were also launched and the SOUSY radar, located near the launch site, measured mesospheric turbulence. Electron density irregularities and strong gradients were measured by the rocket probes in the region of most intense backscatter observed by the radar. The electron density profiles (8 to 4 on ascent and 4 on descent) show very different characteristics in the peak scattering region and show marked spatial and temporal variability. These data are intercompared and discussed.

  18. MACS low-background doubly focusing neutron monochromator

    CERN Document Server

    Smee, S A; Scharfstein, G A; Qiu, Y; Brand, P C; Anand, D K; Broholm, C L

    2002-01-01

    A novel doubly focusing neutron monochromator has been developed as part of the Multi-Analyzer Crystal Spectrometer (MACS) at the NIST Center for Neutron Research. The instrument utilizes a unique vertical focusing element that enables active vertical and horizontal focusing with a large, 357-crystal (1428 cm sup 2), array. The design significantly reduces the amount of structural material in the beam path as compared to similar instruments. Optical measurements verify the excellent focal performance of the device. Analytical and Monte Carlo simulations predict that, when mounted at the NIST cold-neutron source, the device should produce a monochromatic beam (DELTA E=0.2 meV) with flux phi>10 sup 8 n/cm sup 2 s. (orig.)

  19. 76 FR 71797 - Federal Agricultural Mortgage Corporation Funding and Fiscal Affairs; Farmer Mac Investments and...

    Science.gov (United States)

    2011-11-18

    ... diligence procedures that are required for investments, but we do not intend to change the fundamental... Federal Agricultural Mortgage Corporation Funding and Fiscal Affairs; Farmer Mac Investments and Liquidity... Mortgage Corporation Funding and Fiscal Affairs; Farmer Mac Investments and Liquidity Management AGENCY...

  20. A MacWilliams Identity for Convolutional Codes: The General Case

    OpenAIRE

    Gluesing-Luerssen, Heide; Schneider, Gert

    2008-01-01

    A MacWilliams Identity for convolutional codes will be established. It makes use of the weight adjacency matrices of the code and its dual, based on state space realizations (the controller canonical form) of the codes in question. The MacWilliams Identity applies to various notions of duality appearing in the literature on convolutional coding theory.

  1. A MacWilliams Identity for Convolutional Codes : The General Case

    NARCIS (Netherlands)

    Gluesing-Luerssen, Heide; Schneider, Gert

    A MacWilliams Identity for convolutional codes will be established. It makes use of the weight adjacency matrices of the code and its dual, based on state space realizations (the controller canonical form) of the codes in question. The MacWilliams Identity applies to various notions of duality

  2. Poincaré-MacMillan Equations of Motion for a Nonlinear Nonholonomic Dynamical System

    Science.gov (United States)

    Amjad, Hussain; Syed Tauseef, Mohyud-Din; Ahmet, Yildirim

    2012-03-01

    MacMillan's equations are extended to Poincaré's formalism, and MacMillan's equations for nonlinear nonholonomic systems are obtained in terms of Poincaré parameters. The equivalence of the results obtained here with other forms of equations of motion is demonstrated. An illustrative example of the theory is provided as well.

  3. Public Relations as "Practice": Applying the Theory of Alasdair MacIntyre.

    Science.gov (United States)

    Leeper, Roy V.; Leeper, Kathie A.

    2001-01-01

    Considers how public relation's search for a unifying theory may be fulfilled through application of Alasdair MacIntyre's concept of a "practice," a very specific and value-laden concept. Explores what it would mean to be a public relations practice in MacIntyre's concept of the term and argues that such an approach to public relations…

  4. 78 FR 5320 - Federal Agricultural Mortgage Corporation Funding and Fiscal Affairs; Farmer Mac Capital Planning

    Science.gov (United States)

    2013-01-25

    ... the business planning period a required discussion of how factors might impact Farmer Mac's current... discussion of any expected changes to Farmer Mac's business plan that are likely to have a material impact on... conditions that cause increases in delinquency rates caused by any variety of factors (e.g., widespread...

  5. Geochemistry and petrography of the MacAlpine Hills lunar meteorites

    Science.gov (United States)

    Lindstrom, Marilyn M.; Mckay, David S.; Wentworth, Susan J.; Martinez, Rene R.; Mittlefehldt, David W.; Wang, Ming-Sheng; Lipschutz, Michael E.

    1991-01-01

    MacAlpine Hills 88104 and 88105, anorthositic lunar meteorites recovered form the same area in Antartica, are characterized. Petrographic studies show that MAC88104/5 is a polymict breccia dominated by impact melt clasts. It is better classified as a fragmental breccia than a regolith breccia. The bulk composition is ferroan and highly aluminous (Al2O3-28 percent).

  6. THE EFFECT OF TEMPERATURE ON THE GROWTH OF MYCOBACTERIUM AVIUM COMPLEX (MAC) ORGANISMS

    Science.gov (United States)

    MAC organisms are able to grow, persist, and colonize in water distribution systems and may amplify in hospital hot water systems. This study examined the response of MAC organisms (M. avium, M. intracellulare, and MX) to a range of temperatures commonly associated with drinking...

  7. Protocol design and analysis for cooperative wireless networks

    CERN Document Server

    Song, Wei; Jin, A-Long

    2017-01-01

    This book focuses on the design and analysis of protocols for cooperative wireless networks, especially at the medium access control (MAC) layer and for crosslayer design between the MAC layer and the physical layer. It highlights two main points that are often neglected in other books: energy-efficiency and spatial random distribution of wireless devices. Effective methods in stochastic geometry for the design and analysis of wireless networks are also explored. After providing a comprehensive review of existing studies in the literature, the authors point out the challenges that are worth further investigation. Then, they introduce several novel solutions for cooperative wireless network protocols that reduce energy consumption and address spatial random distribution of wireless nodes. For each solution, the book offers a clear system model and problem formulation, details of the proposed cooperative schemes, comprehensive performance analysis, and extensive numerical and simulation results that validate th...

  8. Identifying The Purchasing Power Parity of Indonesia Rupiah (IDR based on BIG MAC Index

    Directory of Open Access Journals (Sweden)

    Tongam Sihol Nababan

    2016-12-01

    Full Text Available The aim of this study is to identify : (1 profile of exchange rate and purchasing power parity of IDR against US $ based on Big Mac Index compared to the exchange rate of other countries, and (2 the position of the Big Mac Affordability of  Indonesia compared to other ASEAN countries. The results showed that based on Big Mac index during the period April 1998 up to January 2015, IDR exchange rate tends to be undervalued against the USA dollar. The cause of the currency tends to be in a position of undervalued due to the components of non-tradable have not been included in Big Mac index. The index of Big Mac Affordability indicates that there is a great disparity of income between Singapore and five other ASEAN countries. The purchasing power of the real income of the people in Singapore is nearly five times the real income of the people in Indonesia.

  9. Impact of MAC Delay on AUV Localization: Underwater Localization Based on Hyperbolic Frequency Modulation Signal.

    Science.gov (United States)

    Kim, Sungryul; Yoo, Younghwan

    2018-01-26

    Medium Access Control (MAC) delay which occurs between the anchor node's transmissions is one of the error sources in underwater localization. In particular, in AUV localization, the MAC delay significantly degrades the ranging accuracy. The Cramer-Rao Low Bound (CRLB) definition theoretically proves that the MAC delay significantly degrades the localization performance. This paper proposes underwater localization combined with multiple access technology to decouple the localization performance from the MAC delay. Towards this goal, we adopt hyperbolic frequency modulation (HFM) signal that provides multiplexing based on its good property, high-temporal correlation. Owing to the multiplexing ability of the HFM signal, the anchor nodes can transmit packets without MAC delay, i.e., simultaneous transmission is possible. In addition, the simulation results show that the simultaneous transmission is not an optional communication scheme, but essential for the localization of mobile object in underwater.

  10. Interference Analysis Status and Plans for Aeronautical Mobile Airport Communications System (AeroMACS)

    Science.gov (United States)

    Kerczewski, Robert J.; Wilson, Jeffrey D.

    2010-01-01

    Interference issues related to the operation of an aeronautical mobile airport communications system (AeroMACS) in the C-Band (specifically 5091-5150 MHz) is being investigated. The issue of primary interest is co-channel interference from AeroMACS into mobile-satellite system (MSS) feeder uplinks. The effort is focusing on establishing practical limits on AeroMACS transmissions from airports so that the threshold of interference into MSS is not exceeded. The analyses are being performed with the software package Visualyse Professional, developed by Transfinite Systems Limited. Results with omni-directional antennas and plans to extend the models to represent AeroMACS more accurately will be presented. These models should enable realistic analyses of emerging AeroMACS designs to be developed from NASA Test Bed, RTCA 223, and European results.

  11. Unlocking radio broadcasts

    DEFF Research Database (Denmark)

    Skov, Mette; Lykke, Marianne

    2012-01-01

    This poster reports the preliminary results of a user study uncovering the information seeking behaviour of humanities scholars dedicated to radio research. The study is part of an interdisciplinary research project on radio culture and auditory resources. The purpose of the study is to inform...... the design of information architecture and interaction design of a research infrastructure that will enable future radio and audio based research. Results from a questionnaire survey on humanities scholars‟ research interest and information needs, preferred access points, and indexing levels are reported....... Finally, a flexible metadata schema is suggested, that includes both general metadata and highly media and research project specific metadata....

  12. Radio y elecciones

    Directory of Open Access Journals (Sweden)

    Alma Rosa Alva de la Selva

    2000-01-01

    Full Text Available En este trabajo se analiza el comportamiento de la radio en México ante la contienda electoral de julio de 2000. Se examina el papel de la radio como espacio para la discusión política, así como el tratamiento informativo que hizo del tema. Asimismo, se analiza la posible repercusión de factores de reciente surgimiento en el panorama radiofónico para un manejo más autónomo de la información política en la radio

  13. Functional characterization of the copper transcription factor AfMac1 from Aspergillus fumigatus.

    Science.gov (United States)

    Park, Yong-Sung; Kim, Tae-Hyoung; Yun, Cheol-Won

    2017-07-03

    Although copper functions as a cofactor in many physiological processes, copper overload leads to harmful effects in living cells. Thus, copper homeostasis is tightly regulated. However, detailed copper metabolic pathways have not yet been identified in filamentous fungi. In this report, we investigated the copper transcription factor AfMac1 ( A spergillus f umigatus Mac1 homolog) and identified its regulatory mechanism in A. fumigatus AfMac1 has domains homologous to the DNA-binding and copper-binding domains of Mac1 from Saccharomyces cerevisiae , and AfMac1 efficiently complemented Mac1 in S. cerevisiae Expression of Afmac1 resulted in CTR1 up-regulation, and mutation of the DNA-binding domain of Afmac1 failed to activate CTR1 expression in S. cerevisiae The Afmac1 deletion strain of A. fumigatus failed to grow in copper-limited media, and its growth was restored by introducing ctrC We found that AfMac1 specifically bound to the promoter region of ctrC based on EMSA. The AfMac1-binding motif 5'-TGTGCTCA-3' was identified from the promoter region of ctrC , and the addition of mutant ctrC lacking the AfMac1-binding motif failed to up-regulate ctrC in A. fumigatus Furthermore, deletion of Afmac1 significantly reduced strain virulence and activated conidial killing activity by neutrophils and macrophages. Taken together, these results suggest that AfMac1 is a copper transcription factor that regulates cellular copper homeostasis in A. fumigatus . © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

  14. Social cognitive radio networks

    CERN Document Server

    Chen, Xu

    2015-01-01

    This brief presents research results on social cognitive radio networks, a transformational and innovative networking paradigm that promotes the nexus between social interactions and cognitive radio networks. Along with a review of the research literature, the text examines the key motivation and challenges of social cognitive radio network design. Three socially inspired distributed spectrum sharing mechanisms are introduced: adaptive channel recommendation mechanism, imitation-based social spectrum sharing mechanism, and evolutionarily stable spectrum access mechanism. The brief concludes with a discussion of future research directions which ascertains that exploiting social interactions for distributed spectrum sharing will advance the state-of-the-art of cognitive radio network design, spur a new line of thinking for future wireless networks, and enable novel wireless service and applications.

  15. NOAA Weather Radio

    Science.gov (United States)

    del tiempo incluido. Si eres quieres ser avisado de las advertencias y relojes de día o de noche, un Weather Radio relojes son independientes o basadas en el Condado (parroquia basados en Luisiana), aunque

  16. The digital sport radio.

    Directory of Open Access Journals (Sweden)

    Hilario José ROMERO BEJARANO

    2014-07-01

    Full Text Available Radio has been immersed in recent years in a phase of technological integration and business of multimedia, as well as diversification of systems and channels for broadcasting. In addition, Internet has been consolidated as the platform of digital radio that more has evolved as a result of its continued expansion. However, the merger radio-Internet must be understood as a new form of communication, and not solely as a new complementary medium. In this context, it is of great interest to analyze that transformations in the way of reception, contents, languages, programs and schedules, has brought with it for the radio that integration. To this end is taken as main reference the sports areas, a key aspect and broadly representative of the current broadcasting landscape.

  17. Music, radio and mediatization

    DEFF Research Database (Denmark)

    Michelsen, Morten; Krogh, Mads

    2016-01-01

    of mediatization where media as such seem to be ascribed agency. Instead, we consider historical accounts of music–radio in order to address the complex nonlinearity of concrete processes of mediatization as they take place in the multiple meetings between a decentred notion of radio and musical life.......Mediatization has become a key concept for understanding the relations between media and other cultural and social fields. Contributing to the discussions related to the concept of mediatization, this article discusses how practices of radio and music(al life) influence each other. We follow Deacon......’s and Stanyer’s advice to supplement the concept of mediatization with ‘a series of additional concepts at lower levels of abstraction’ and suggest, in this respect, the notion of heterogeneous milieus of music–radio. Hereby, we turn away from the all-encompassing perspectives related to the concept...

  18. ITSY Handheld Software Radio

    National Research Council Canada - National Science Library

    Bose, Vanu

    2001-01-01

    .... A handheld software radio platform would enable the construction of devices that could inter-operate with multiple legacy systems, download new waveforms and be used to construct adhoc networks...

  19. Structure in radio galaxies

    International Nuclear Information System (INIS)

    Breugel, W. van.

    1980-01-01

    It is shown that radio jets are a rather common phenomenon in radio galaxies. Jets can be disguised as trails in head-tail sources, bridges in double sources or simply remain undetected because of lack of resolution and sensitivity. It is natural to associate these jets with the channels which had previously been suggested to supply energy to the extended radio lobes. The observations of optical emission suggest that a continuous non-thermal spectrum extending from 10 9 to 10 15 Hz is a common property of jets. Because significant amounts of interstellar matter are also observed in each of the galaxies surveyed it seems that models for jets which involve an interaction with this medium may be most appropriate. New information about the overall structure of extended radio sources has been obtained from the detailed multifrequency study with the WSRT. (Auth.)

  20. Wireless radio a history

    CERN Document Server

    Coe, Lewis

    2006-01-01

    ""Informative...recommended""--Choice; ""interesting...a good read...well worth reading""--Contact Magazine. This history first looks at Marconi's wireless communications system and then explores its many applications, including marine radio, cellular telephones, police and military uses, television and radar. Radio collecting is also discussed, and brief biographies are provided for the major figures in the development and use of the wireless.

  1. ¿Radios ciudadanas?

    OpenAIRE

    López Vigil, José Ignacio

    1998-01-01

    Educativas, sindicales, populares, comunitarias, libres, rebeldes, participativas, alternativas, alterativas, han sido las denominaciones de la radio cuando su proyecto está al servicio de la gente. Palabras apropiadas y nobles -dice elautor-pero devaluadas, a las que ahora se agrega la radio ciudadana, para relievarla como ejercicio depoder y espacio de verdadera participación de la genteenla vida de su nación.

  2. Receiver-initiated medium access control protocols for wireless sensor networks

    DEFF Research Database (Denmark)

    Fafoutis, Xenofon; Di Mauro, Alessio; Vithanage, Madava D.

    2015-01-01

    One of the fundamental building blocks of a Wireless Sensor Network (WSN) is the Medium Access Control (MAC) protocol, that part of the system governing when and how two independent neighboring nodes activate their respective transceivers to directly interact. Historically, data exchange has always...

  3. Comparing conVEntional RadioTherapy with stereotactIC body radiotherapy in patients with spinAL metastases: study protocol for an randomized controlled trial following the cohort multiple randomized controlled trial design

    International Nuclear Information System (INIS)

    Velden, Joanne M. van der; Verkooijen, Helena M.; Seravalli, Enrica; Hes, Jochem; Gerlich, A. Sophie; Kasperts, Nicolien; Eppinga, Wietse S. C.; Verlaan, Jorrit-Jan; Vulpen, Marco van

    2016-01-01

    Standard radiotherapy is the treatment of first choice in patients with symptomatic spinal metastases, but is only moderately effective. Stereotactic body radiation therapy is increasingly used to treat spinal metastases, without randomized evidence of superiority over standard radiotherapy. The VERTICAL study aims to quantify the effect of stereotactic radiation therapy in patients with metastatic spinal disease. This study follows the ‘cohort multiple Randomized Controlled Trial’ design. The VERTICAL study is conducted within the PRESENT cohort. In PRESENT, all patients with bone metastases referred for radiation therapy are enrolled. For each patient, clinical and patient-reported outcomes are captured at baseline and at regular intervals during follow-up. In addition, patients give informed consent to be offered experimental interventions. Within PRESENT, 110 patients are identified as a sub cohort of eligible patients (i.e. patients with unirradiated painful, mechanically stable spinal metastases who are able to undergo stereotactic radiation therapy). After a protocol amendment, also patients with non-spinal bony metastases are eligible. From the sub cohort, a random selection of patients is offered stereotactic radiation therapy (n = 55), which patients may accept or refuse. Only patients accepting stereotactic radiation therapy sign informed consent for the VERTICAL trial. Non-selected patients (n = 55) receive standard radiotherapy, and are not aware of them serving as controls. Primary endpoint is pain response after three months. Data will be analyzed by intention to treat, complemented by instrumental variable analysis in case of substantial refusal of the stereotactic radiation therapy in the intervention arm. This study is designed to quantify the treatment response after (stereotactic) radiation therapy in patients with symptomatic spinal metastases. This is the first randomized study in palliative care following the cohort multiple Randomized

  4. Classics in radio astronomy

    CERN Document Server

    Sullivan, Woodruff Turner

    1982-01-01

    Radio techniques were the nrst to lead astronomy away from the quiescent and limited Universe revealed by traditional observations at optical wave­ lengths. In the earliest days of radio astronomy, a handful of radio physicists and engineers made one startling discovery after another as they opened up the radio sky. With this collection of classic papers and the extensive intro­ ductory material, the reader can experience these exciting discoveries, as well as understand the developing techniques and follow the motivations which prompted the various lines of inquiry. For instance he or she will follow in detail the several attempts to detect radio waves from the sun at the turn of the century; the unravelling by Jansky of a "steady hiss type static"; the incredible story of Reber who built a 9 meter dish in his backyard in 1937 and then mapped the Milky Way; the vital discoveries by Hey and colleagues of radio bursts from the Sun and of a discrete source in the constellation of Cygnus; the development of re...

  5. Development of high-reliable real-time communication network protocol for SMART

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ki Sang; Kim, Young Sik [Korea National University of Education, Chongwon (Korea); No, Hee Chon [Korea Advanced Institute of Science and Technology, Taejon (Korea)

    1999-04-01

    In this research, we first define protocol subsets for SMART(System-integrated Modular Advanced Reactor) communication network based on the requirement of SMART MMIS transmission delay and traffic requirements and OSI(Open System Interconnection) 7 layers' network protocol functions. Also, current industrial purpose LAN protocols are analyzed and the applicability of commercialized protocols are checked. For the suitability test, we have applied approximated SMART data traffic and maximum allowable transmission delay requirement. With the simulation results, we conclude that IEEE 802.5 and FDDI which is an ANSI standard, is the most suitable for SMART. We further analyzed the FDDI and token ring protocols for SMART and nuclear plant network environment including IEEE 802.4, IEEE 802.5, and ARCnet. The most suitable protocol for SMART is FDDI and FDDI MAC and RMT protocol specifications have been verified with LOTOS and the verification results show that FDDI MAC and RMT satisfy the reachability and liveness, but does not show deadlock and livelock. Therefore, we conclude that FDDI MAC and RMT is highly reliable protocol for SMART MMIS network. After that, we consider the stacking fault of IEEE 802.5 token ring protocol and propose a fault tolerant MAM(Modified Active Monitor) protocol. The simulation results show that the MAM protocol improves lower priority traffic service rate when stacking fault occurs. Therefore, proposed MAM protocol can be applied to SMART communication network for high reliability and hard real-time communication purpose in data acquisition and inter channel network. (author). 37 refs., 79 figs., 39 tabs.

  6. Authentication of Radio Frequency Identification Devices Using Electronic Characteristics

    Science.gov (United States)

    Chinnappa Gounder Periaswamy, Senthilkumar

    2010-01-01

    Radio frequency identification (RFID) tags are low-cost devices that are used to uniquely identify the objects to which they are attached. Due to the low cost and size that is driving the technology, a tag has limited computational capabilities and resources. This limitation makes the implementation of conventional security protocols to prevent…

  7. Solar radio observations and interpretations

    International Nuclear Information System (INIS)

    Rosenberg, H.

    1976-01-01

    The recent solar radio observations related to flares are reviewed for the frequency range of a few kilohertz to several gigahertz. The analysis of the radio data leads to boundary conditions on the acceleration processes which are responsible for the fast particles which cause radio emission. The role and cause of plasma turbulence at the plasma-frequency and at much lower frequencies is discussed in relation to the acceleration processes and the radio emission mechanisms for the various radio bursts. (author)

  8. Cryptographic Protocols:

    DEFF Research Database (Denmark)

    Geisler, Martin Joakim Bittel

    cryptography was thus concerned with message confidentiality and integrity. Modern cryptography cover a much wider range of subjects including the area of secure multiparty computation, which will be the main topic of this dissertation. Our first contribution is a new protocol for secure comparison, presented...... implemented the comparison protocol in Java and benchmarks show that is it highly competitive and practical. The biggest contribution of this dissertation is a general framework for secure multiparty computation. Instead of making new ad hoc implementations for each protocol, we want a single and extensible...... in Chapter 2. Comparisons play a key role in many systems such as online auctions and benchmarks — it is not unreasonable to say that when parties come together for a multiparty computation, it is because they want to make decisions that depend on private information. Decisions depend on comparisons. We have...

  9. Antibiotic Resistance Mediated by the MacB ABC Transporter Family: A Structural and Functional Perspective

    Directory of Open Access Journals (Sweden)

    Nicholas P. Greene

    2018-05-01

    Full Text Available The MacB ABC transporter forms a tripartite efflux pump with the MacA adaptor protein and TolC outer membrane exit duct to expel antibiotics and export virulence factors from Gram-negative bacteria. Here, we review recent structural and functional data on MacB and its homologs. MacB has a fold that is distinct from other structurally characterized ABC transporters and uses a unique molecular mechanism termed mechanotransmission. Unlike other bacterial ABC transporters, MacB does not transport substrates across the inner membrane in which it is based, but instead couples cytoplasmic ATP hydrolysis with transmembrane conformational changes that are used to perform work in the extra-cytoplasmic space. In the MacAB-TolC tripartite pump, mechanotransmission drives efflux of antibiotics and export of a protein toxin from the periplasmic space via the TolC exit duct. Homologous tripartite systems from pathogenic bacteria similarly export protein-like signaling molecules, virulence factors and siderophores. In addition, many MacB-like ABC transporters do not form tripartite pumps, but instead operate in diverse cellular processes including antibiotic sensing, cell division and lipoprotein trafficking.

  10. Antibiotic Resistance Mediated by the MacB ABC Transporter Family: A Structural and Functional Perspective

    Science.gov (United States)

    Greene, Nicholas P.; Kaplan, Elise; Crow, Allister; Koronakis, Vassilis

    2018-01-01

    The MacB ABC transporter forms a tripartite efflux pump with the MacA adaptor protein and TolC outer membrane exit duct to expel antibiotics and export virulence factors from Gram-negative bacteria. Here, we review recent structural and functional data on MacB and its homologs. MacB has a fold that is distinct from other structurally characterized ABC transporters and uses a unique molecular mechanism termed mechanotransmission. Unlike other bacterial ABC transporters, MacB does not transport substrates across the inner membrane in which it is based, but instead couples cytoplasmic ATP hydrolysis with transmembrane conformational changes that are used to perform work in the extra-cytoplasmic space. In the MacAB-TolC tripartite pump, mechanotransmission drives efflux of antibiotics and export of a protein toxin from the periplasmic space via the TolC exit duct. Homologous tripartite systems from pathogenic bacteria similarly export protein-like signaling molecules, virulence factors and siderophores. In addition, many MacB-like ABC transporters do not form tripartite pumps, but instead operate in diverse cellular processes including antibiotic sensing, cell division and lipoprotein trafficking. PMID:29892271

  11. MAC Version 3.2, MBA Version 1.3 acceptance test summary report

    International Nuclear Information System (INIS)

    Russell, V.K.

    1994-01-01

    The K Basins Materials Accounting (MAC) and Materials Balance (MBA) programs had the Paradox Conversion to 4.0 ATP run to check out the systems. This report describes the results of the test and provides the signoff sheets associated with the testing. The test primarily concentrated on verifying that MAC and MBA software would run properly in the Paradox 4.0 environment. Changes in the MAC and MBA programs were basically limited to superficial items needed to accommodate the enhanced method of execution

  12. Learn AppleScript The Comprehensive Guide to Scripting and Automation on MAC OS X

    CERN Document Server

    Rosenthal, Hanaan

    2009-01-01

    AppleScript is an English-like, easy-to-understand scripting language built into every Mac. AppleScript can automate hundreds of AppleScriptable applications, performing tasks both large and small, complex and simple. Learn AppleScript: The Comprehensive Guide to Scripting and Automation on Mac OS X, Third Edition has been completely updated for Mac OS X Snow Leopard. It's all here, with an emphasis on practical information that will help you solve any automation problem-from the most mundane repetitive tasks to highly integrated workflows of complex systems. * Friendly enough for beginners, d

  13. Are hamburgers harmless? : the Big Mac Index in the twenty-first century

    OpenAIRE

    Soo, Kwok Tong

    2016-01-01

    We make use of The Economist’s Big Mac Index (BMI) to investigate the Law of One Price (LOP) and whether the BMI can be used to predict future exchange rate and price changes. Deviations from Big Mac parity decay quickly, in approximately 1 year. The BMI is a better predictor of relative price changes than of exchange rate changes, and performs best when predicting a depreciation of a currency relative to the US dollar. Convergence to Big Mac parity occurs more rapidly for currencies with som...

  14. Identifying The Purchasing Power Parity of Indonesia Rupiah (IDR) based on BIG MAC Index

    OpenAIRE

    Tongam Sihol Nababan

    2016-01-01

    The aim of this study is to identify : (1) profile of exchange rate and purchasing power parity of IDR against US $ based on Big Mac Index compared to the exchange rate of other countries, and (2) the position of the Big Mac Affordability of Indonesia compared to other ASEAN countries. The results showed that based on Big Mac index during the period April 1998 up to January 2015, IDR exchange rate tends to be undervalued against the USA dollar. The cause of the currency tends to be in a posi...

  15. Immunochemical protocols

    National Research Council Canada - National Science Library

    Pound, John D

    1998-01-01

    ... easy and important refinements often are not published. This much anticipated 2nd edition of Immunochemzcal Protocols therefore aims to provide a user-friendly up-to-date handbook of reliable techniques selected to suit the needs of molecular biologists. It covers the full breadth of the relevant established immunochemical methods, from protein blotting and immunoa...

  16. Tools of radio astronomy

    CERN Document Server

    Wilson, Thomas L; Hüttemeister, Susanne

    2013-01-01

    This 6th edition of “Tools of Radio Astronomy”, the most used introductory text in radio astronomy, has been revised to reflect the current state of this important branch of astronomy. This includes the use of satellites, low radio frequencies, the millimeter/sub-mm universe, the Cosmic Microwave Background and the increased importance of mm/sub-mm dust emission. Several derivations and presentations of technical aspects of radio astronomy and receivers, such as receiver noise, the Hertz dipole and  beam forming have been updated, expanded, re-worked or complemented by alternative derivations. These reflect advances in technology. The wider bandwidths of the Jansky-VLA and long wave arrays such as LOFAR and mm/sub-mm arrays such as ALMA required an expansion of the discussion of interferometers and aperture synthesis. Developments in data reduction algorithms have been included. As a result of the large amount of data collected in the past 20 years, the discussion of solar system radio astronomy, dust em...

  17. Energy-Efficiency Analysis of a Distributed Queuing Medium Access Control Protocol for Biomedical Wireless Sensor Networks in Saturation Conditions

    Directory of Open Access Journals (Sweden)

    Christos Verikoukis

    2011-01-01

    Full Text Available The aging population and the high quality of life expectations in our society lead to the need of more efficient and affordable healthcare solutions. For this reason, this paper aims for the optimization of Medium Access Control (MAC protocols for biomedical wireless sensor networks or wireless Body Sensor Networks (BSNs. The hereby presented schemes always have in mind the efficient management of channel resources and the overall minimization of sensors’ energy consumption in order to prolong sensors’ battery life. The fact that the IEEE 802.15.4 MAC does not fully satisfy BSN requirements highlights the need for the design of new scalable MAC solutions, which guarantee low-power consumption to the maximum number of body sensors in high density areas (i.e., in saturation conditions. In order to emphasize IEEE 802.15.4 MAC limitations, this article presents a detailed overview of this de facto standard for Wireless Sensor Networks (WSNs, which serves as a link for the introduction and initial description of our here proposed Distributed Queuing (DQ MAC protocol for BSN scenarios. Within this framework, an extensive DQ MAC energy-consumption analysis in saturation conditions is presented to be able to evaluate its performance in relation to IEEE 802.5.4 MAC in highly dense BSNs. The obtained results show that the proposed scheme outperforms IEEE 802.15.4 MAC in average energy consumption per information bit, thus providing a better overall performance that scales appropriately to BSNs under high traffic conditions. These benefits are obtained by eliminating back-off periods and collisions in data packet transmissions, while minimizing the control overhead.

  18. Galactic radio astronomy

    CERN Document Server

    Sofue, Yoshiaki

    2017-01-01

    This book is a concise primer on galactic radio astronomy for undergraduate and graduate students, and provides wide coverage of galactic astronomy and astrophysics such as the physics of interstellar matter and the dynamics and structure of the Milky Way Galaxy and galaxies. Radio astronomy and its technological development have led to significant progress in galactic astronomy and contributed to understanding interstellar matter and galactic structures. The book begins with the fundamental physics of radio-wave radiation, i.e., black body radiation, thermal emission, synchrotron radiation, and HI and molecular line emissions. The author then gives overviews of ingredients of galactic physics, including interstellar matter such as the neutral (HI), molecular hydrogen, and ionized gases, as well as magnetic fields in galaxies. In addition, more advanced topics relevant to the Galaxy and galaxies are also contained here: star formation, supernova remnants, the Galactic Center and black holes, galactic dynamics...

  19. Radio structure in quasars

    International Nuclear Information System (INIS)

    Barthel, P.D.

    1984-01-01

    In this thesis, observational attention is given to the extended extragalactic radio sources associated with quasars. The isolated compact radio sources, often identified with quasars, are only included in the discussions. Three aspects of the radio structure in quasars and their cosmic evolution are considered: a study of the parsec scale morphology in quasar cores, in relation to the extended morphologies; an investigation of possible epoch dependent hotspot properties as well as a more detailed investigation of this fine scale structure; a VLA project was carried out to obtain morphological information on scales of 0.5 arcsec on high redshift quasars and to investigate possible epoch dependent morphological properties. MERLIN observations at 0.1 arcsec resolution to supplement the VLA data were initiated. (Auth.)

  20. QoS and energy management in cognitive radio network case study approach

    CERN Document Server

    Mishra, Vishram; Lau, Chiew-Tong

    2017-01-01

    This book covers the important aspects involved in making cognitive radio devices portable, mobile and green, while also extending their service life. At the same time, it presents a variety of established theories and practices concerning cognitive radio from academia and industry. Cognitive radio can be utilized as a backbone communication medium for wireless devices. To effectively achieve its commercial application, various aspects of quality of service and energy management need to be addressed. The topics covered in the book include energy management and quality of service provisioning at Layer 2 of the protocol stack from the perspectives of medium access control, spectrum selection, and self-coexistence for cognitive radio networks.

  1. Analysis of an Adaptive P-Persistent MAC Scheme for WLAN Providing Delay Fairness

    Science.gov (United States)

    Yen, Chih-Ming; Chang, Chung-Ju; Chen, Yih-Shen; Huang, Ching Yao

    The paper proposes and analyzes an adaptive p-persistent-based (APP) medium access control (MAC) scheme for IEEE 802.11 WLAN. The APP MAC scheme intends to support delay fairness for every station in each access, denoting small delay variance. It differentiates permission probabilities of transmission for stations which are incurred with various packet delays. This permission probability is designed as a function of the numbers of retransmissions and re-backoffs so that stations with larger packet delay are endowed with higher permission probability. Also, the scheme is analyzed by a Markov-chain analysis, where the collision probability, the system throughput, and the average delay are successfully obtained. Numerical results show that the proposed APP MAC scheme can attain lower mean delay and higher mean throughput. In the mean time, simulation results are given to justify the validity of the analysis, and also show that the APP MAC scheme can achieve more delay fairness than conventional algorithms.

  2. 78 FR 26711 - Federal Agricultural Mortgage Corporation Funding and Fiscal Affairs; Farmer Mac Liquidity...

    Science.gov (United States)

    2013-05-08

    ... Funding and Fiscal Affairs; Farmer Mac Liquidity Management ACTION: Proposed rule; reopening of comment... proposed rule that would amend its liquidity management regulations for the Federal Agricultural Mortgage... comment on the proposed liquidity regulations. [[Page 26712

  3. The Cognition of Multiaircraft Control (MAC): Cognitive Ability Predictors, Working Memory, Interference, and Attention Control in Radio Communication

    Science.gov (United States)

    2015-03-26

    The digital file containing the survey and data collection results, as well as the study write-up will be secured on a password-protected computer...Sep 30, 2014. PROFESSIONAL AND HONOR SOCIETIES 2012 - Present Psi Chi, Psychology Honors Society, Vice President 2014 - Present Sigma Iota Epsilon...Multiaircraft Control, Attention control, Working memory, Proactive interference 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU or SAR

  4. Radio Emission from Supernovae

    International Nuclear Information System (INIS)

    Weiler, Kurt W.; Panagia, Nino; Sramek, Richard A.; Van Dyk, Schuyler D.; Williams, Christopher L.; Stockdale, Christopher J.; Kelley, Matthew T.

    2009-01-01

    Study of radio supernovae over the past 27 years includes more than three dozen detected objects and more than 150 upper limits. From this work it is possible to identify classes of radio properties, demonstrate conformance to and deviations from existing models, estimate the density and structure of the circumstellar material and, by inference, the evolution of the presupernova stellar wind, and reveal the last stages of stellar evolution before explosion. It is also possible to detect ionized hydrogen along the line of sight, to demonstrate binary properties of the presupernova stellar system, and to detect dumpiness of the circumstellar material.

  5. Radio emission from Jupiter

    International Nuclear Information System (INIS)

    Velusamy, T.

    1976-01-01

    The basic features of the different radio emissions from the planet Jupiter are reviewed. These radio emissions characterized into three types as thermal, decimetric and decametric, are discussed. The coherent emission mechanism for the origin of the decametric bursts and the acceleration mechanism for relativistic electrons in the decimetric radiation have not been properly understood. The emissions are much related to the magnetic field of Jupiter. The system III rotation period for Jupiter has been calculated as 092 55 m 29.74 S. (A.K.)

  6. ¿Radios Comunitarias?

    OpenAIRE

    José Ignacio López Vigil

    2015-01-01

    Varias han sido las denominaciones dadas a la radio cuando su proyecto está al servicio de la gente. Palabras apropiadas pero devaluadas al decir del autor, a las que ahora se suma otras radios ciudadanas. Ciudadana para relievarla como ejercicio de poder y espacio de verdadera participación de la gente en la vida de su nación. Ciudadanos son los que piensan con cabeza propia y pesan en la opinión pública. Presenta una sinopsis de la historia de éstas desde 1974. Señala que la competencia obl...

  7. A Critique of MacIntyrean Morality From a Kantian Perspective

    OpenAIRE

    Krishna Mani Pathak

    2014-01-01

    This article is a critical examination of MacIntyre’s notion of morality in reference to Kant’s deontological moral theory. The examination shows that MacIntyre (a) criticizes Kant’s moral theory to defend virtue ethics or neo-Aristotelian ethics with a weak notion of morality; (b) favors the idea of local morality, which does not leave any room for moral assessment and reciprocity in an intercultural domain; and (c) f...

  8. Strategy, Operational Art and MacArthur in the Southwest Pacific 1944

    Science.gov (United States)

    2016-05-26

    Guinea Campaign.11 It studies the campaign exclusively from the February 1944 through October 1944. The choice in dates argues that the campaign...the Pacific. King continued to maintain that MacArthur’s line of operation in SWPA, toward the Philippines to the exclusion of the central Pacific...with Nimitz allowed MacArthur the rare luxury of aircraft carriers providing a protective bubble over both the Morotai and Palaus operations. Escort

  9. Are Rural Costs of Living Lower? Evidence from a Big Mac Index Approach

    OpenAIRE

    Scott Loveridge; Dusan Paredes

    2015-01-01

    Rural leaders can point to low housing costs as a reason that their area should be competitive for business attraction. To what extent do rural housing costs offset transportation and other locational disadvantages in costs structures? The US lacks information to systematically answer the question. We adapt a strategy employed by The Economist in exploring purchasing power parity: the Big Mac Index. We gather information on Big Mac prices with a random sample of restaurants across the contigu...

  10. Profile of a leader. Alena Jean MacMaster: administrator, educator, professional activist and community advocate.

    Science.gov (United States)

    Gautreau, G; Winans, P

    1999-01-01

    This paper profiles Alena Jean MacMaster, an extraordinary nurse leader, activist, visionary and humanitarian from New Brunswick. Her determination and drive were instrumental in fostering the development and progression of health care, nursing education and nursing services at the local, provincial, federal and international levels. "First, loyalty to the institution in which you serve. The patient is the most important person in the entire institution," was Miss MacMaster's guiding principle throughout her career.

  11. MAC Version 3.3, MBA Version 1.3 acceptance test summary report

    International Nuclear Information System (INIS)

    Russell, V.K.

    1994-01-01

    The K Basins Materials Accounting (MAC) and Materials Balance (MBA) programs had the Paradox Code Cleanup ATP run to check out the systems. This report describes the results of the test and provides the signoff sheets associated with the testing. The Acceptance Test results indicate that the MAC and MBA systems are ready for operation using the cleaned up code. The final codes were removed to the production space on the customer server on April 15th

  12. Spectrum management and radio resource management considering cognitive radio systems

    NARCIS (Netherlands)

    Haartsen, J.C.; Wieweg, Lasse; Huschke, Jörg

    2005-01-01

    International fora and some national administrations define a cognitive radio (CR) as a pioneering radio communication system that would be capable of altering and adapting its transmitter and receiver parameters based on communication and the exchange of information with related detectable radio

  13. Functional Implications of an Intermeshing Cogwheel-like Interaction between TolC and MacA in the Action of Macrolide-specific Efflux Pump MacAB-TolC*

    Science.gov (United States)

    Xu, Yongbin; Song, Saemee; Moeller, Arne; Kim, Nahee; Piao, Shunfu; Sim, Se-Hoon; Kang, Mooseok; Yu, Wookyung; Cho, Hyun-Soo; Chang, Iksoo; Lee, Kangseok; Ha, Nam-Chul

    2011-01-01

    Macrolide-specific efflux pump MacAB-TolC has been identified in diverse Gram-negative bacteria including Escherichia coli. The inner membrane transporter MacB requires the outer membrane factor TolC and the periplasmic adaptor protein MacA to form a functional tripartite complex. In this study, we used a chimeric protein containing the tip region of the TolC α-barrel to investigate the role of the TolC α-barrel tip region with regard to its interaction with MacA. The chimeric protein formed a stable complex with MacA, and the complex formation was abolished by substitution at the functionally essential residues located at the MacA α-helical tip region. Electron microscopic study delineated that this complex was made by tip-to-tip interaction between the tip regions of the α-barrels of TolC and MacA, which correlated well with the TolC and MacA complex calculated by molecular dynamics. Taken together, our results demonstrate that the MacA hexamer interacts with TolC in a tip-to-tip manner, and implies the manner by which MacA induces opening of the TolC channel. PMID:21325274

  14. Functional implications of an intermeshing cogwheel-like interaction between TolC and MacA in the action of macrolide-specific efflux pump MacAB-TolC.

    Science.gov (United States)

    Xu, Yongbin; Song, Saemee; Moeller, Arne; Kim, Nahee; Piao, Shunfu; Sim, Se-Hoon; Kang, Mooseok; Yu, Wookyung; Cho, Hyun-Soo; Chang, Iksoo; Lee, Kangseok; Ha, Nam-Chul

    2011-04-15

    Macrolide-specific efflux pump MacAB-TolC has been identified in diverse gram-negative bacteria including Escherichia coli. The inner membrane transporter MacB requires the outer membrane factor TolC and the periplasmic adaptor protein MacA to form a functional tripartite complex. In this study, we used a chimeric protein containing the tip region of the TolC α-barrel to investigate the role of the TolC α-barrel tip region with regard to its interaction with MacA. The chimeric protein formed a stable complex with MacA, and the complex formation was abolished by substitution at the functionally essential residues located at the MacA α-helical tip region. Electron microscopic study delineated that this complex was made by tip-to-tip interaction between the tip regions of the α-barrels of TolC and MacA, which correlated well with the TolC and MacA complex calculated by molecular dynamics. Taken together, our results demonstrate that the MacA hexamer interacts with TolC in a tip-to-tip manner, and implies the manner by which MacA induces opening of the TolC channel.

  15. Compact radio sources

    International Nuclear Information System (INIS)

    Altschuler, D.R.

    1975-01-01

    Eighty-seven compact radio sources were monitored between 1971 and 1974 with the National Radio Astronomy Observatory interferometer. Both flux density and polarization were measured at intervals of about one month at wavelengths of 3.7 and 11.1 cms. Forty-four sources showed definite variability in their total and/or polarized flux density. The variations in polarization were of a shorter time scale than the corresponding flux density variations. Some of the qualitative features of an expanding source model were observed. The data suggest that some form of injection of relativistic electrons is taking place. The absence of significant depolarization in the variable sources indicates that only a small fraction of the mass of the radio outburst is in the form of non-relativistic plasma. Some of the objects observed belong to the BL-Lacertal class. It is shown that this class is very inhomogeneous in its radio properties. For the violently variable BL-Lacertal type objects the spectrum, flux variations and polarization data strongly suggest that these are very young objects

  16. Valuing commercial radio licences

    NARCIS (Netherlands)

    Kerste, M.; Poort, J.; van Eijk, N.

    2011-01-01

    Within the EU Regulatory Framework, licensees for commercial radio broadcasting may be charged a fee to ensure optimal allocation of scarce resources but not to maximize public revenues. In this paper, it is described how such a fee can be determined for the purpose of licence renewal or extension.

  17. Radio Frequency Identification

    Indian Academy of Sciences (India)

    Radio Frequency Identification (RFID) has been around sinceearly 2000. Its use has currently become commonplace as thecost of RFID tags has rapidly decreased. RFID tags have alsobecome more 'intelligent' with the incorporation of processorsand sensors in them. They are widely used now in manyinnovative ways.

  18. Nanolensed Fast Radio Bursts

    Science.gov (United States)

    Eichler, David

    2017-12-01

    It is suggested that fast radio bursts can probe gravitational lensing by clumpy dark matter objects that range in mass from 10-3 M ⊙-102 M ⊙. They may provide a more sensitive probe than observations of lensings of objects in the Magellanic Clouds, and could find or rule out clumpy dark matter with an extended mass spectrum.

  19. AMATEUR "HAM" RADIO

    Science.gov (United States)

    these cooler months. Did you know your body can cool 25 times faster in water than in air? That water code at 13 or 20 words-per-minute will no longer be required to obtain amateur radio operating be found by contacting the ARRL or using an Internet search engine to search on such topics as "

  20. Radio images of the planets

    International Nuclear Information System (INIS)

    De Pater, I.

    1990-01-01

    Observations at radio wavelengths make possible detailed studies of planetary atmospheres, magnetospheres, and surface layers. The paper addresses the question of what can be learned from interferometric radio images of planets. Results from single-element radio observations are also discussed. Observations of both the terrestrial and the giant planets are considered. 106 refs

  1. An adaptive software defined radio design based on a standard space telecommunication radio system API

    Science.gov (United States)

    Xiong, Wenhao; Tian, Xin; Chen, Genshe; Pham, Khanh; Blasch, Erik

    2017-05-01

    Software defined radio (SDR) has become a popular tool for the implementation and testing for communications performance. The advantage of the SDR approach includes: a re-configurable design, adaptive response to changing conditions, efficient development, and highly versatile implementation. In order to understand the benefits of SDR, the space telecommunication radio system (STRS) was proposed by NASA Glenn research center (GRC) along with the standard application program interface (API) structure. Each component of the system uses a well-defined API to communicate with other components. The benefit of standard API is to relax the platform limitation of each component for addition options. For example, the waveform generating process can support a field programmable gate array (FPGA), personal computer (PC), or an embedded system. As long as the API defines the requirements, the generated waveform selection will work with the complete system. In this paper, we demonstrate the design and development of adaptive SDR following the STRS and standard API protocol. We introduce step by step the SDR testbed system including the controlling graphic user interface (GUI), database, GNU radio hardware control, and universal software radio peripheral (USRP) tranceiving front end. In addition, a performance evaluation in shown on the effectiveness of the SDR approach for space telecommunication.

  2. Analysis of interference performance of tactical radio network

    Science.gov (United States)

    Nie, Hao; Cai, Xiaoxia; Chen, Hong

    2017-08-01

    Mobile Ad hoc network has a strong military background for its development as the core technology of the backbone network of US tactical Internet. And which tactical radio network, is the war in today's tactical use of the Internet more mature form of networking, mainly used in brigade and brigade following forces. This paper analyzes the typical protocol AODV in the tactical radio network, and then carries on the networking. By adding the interference device to the whole network, the battlefield environment is simulated, and then the throughput, delay and packet loss rate are analyzed, and the performance of the whole network and the single node before and after the interference is obtained.

  3. Method of modeling the cognitive radio using Opnet Modeler

    OpenAIRE

    Yakovenko, I. V.; Poshtarenko, V. M.; Kostenko, R. V.

    2012-01-01

    This article is a review of the first wireless standard based on cognitive radio networks. The necessity of wireless networks based on the technology of cognitive radio. An example of the use of standard IEEE 802.22 in Wimax network through which was implemented in the simulation software environment Opnet Modeler. Schedules to check the performance of HTTP and FTP protocols CR network. Simulation results justify the use of standard IEEE 802.22 in wireless networks. Ця стаття являє собою о...

  4. The importance of Radio Quiet Zone (RQZ) for radio astronomy

    Science.gov (United States)

    Umar, Roslan; Abidin, Zamri Zainal; Ibrahim, Zainol Abidin

    2013-05-01

    Most of radio observatories are located in isolated areas. Since radio sources from the universe is very weak, astronomer need to avoid radio frequency interference (RFI) from active spectrum users and radio noise produced by human made (telecommunication, mobile phone, microwave user and many more. There are many observatories around the world are surrounded by a Radio Quiet Zone (RQZ), which is it was set up using public or state laws. A Radio Quiet Zone normally consists of two areas: an exclusive area in which totally radio emissions are forbidden, with restrictions for residents and business developments, and a larger (radius up to 100 km above) coordination area where the power of radio transmission limits to threshold levels. Geographical Information System (GIS) can be used as a powerful tool in mapping large areas with varying RQZ profiles. In this paper, we report the initial testing of the usage of this system in order to identify the areas were suitable for Radio Quiet Zone. Among the important parameters used to develop the database for our GIS are population density, information on TV and telecommunication (mobile phones) transmitters, road networks (highway), and contour shielding. We will also use other information gathered from on-site RFI level measurements on selected 'best' areas generated by the GIS. The intention is to find the best site for the purpose of establishing first radio quiet zones for radio telescope in Malaysia.

  5. Study protocol

    DEFF Research Database (Denmark)

    Smith, Benjamin E; Hendrick, Paul; Bateman, Marcus

    2017-01-01

    avoidance behaviours, catastrophising, self-efficacy, sport and leisure activity participation, and general quality of life. Follow-up will be 3 and 6 months. The analysis will focus on descriptive statistics and confidence intervals. The qualitative components will follow a thematic analysis approach....... DISCUSSION: This study will evaluate the feasibility of running a definitive large-scale trial on patients with patellofemoral pain, within the NHS in the UK. We will identify strengths and weaknesses of the proposed protocol and the utility and characteristics of the outcome measures. The results from...... this study will inform the design of a multicentre trial. TRIAL REGISTRATION: ISRCTN35272486....

  6. MacDonald Dam reconstruction : using roller-compacted concrete

    Energy Technology Data Exchange (ETDEWEB)

    O' Neil, E. [AMEC Earth and Environmental Ltd., Sydney, NS (Canada)

    2007-04-01

    Located in Nova Scotia, the MacDonald Dam was commissioned in 1928. The dam consists of a 122 metre-long, 16 metre-high concrete structure comprised of an intake structure, stoplog openings, and a 34 metre-long free-overflow spillway. A 488 metre-long power canal was added as an upgrade in the 1950s. This paper provided details of the roller-compact concrete (RCC) used in the dam's recent rehabilitation following a dam failure analysis in 2003 by Nova Scotia Power Inc. RCC was chosen to help keep the dam's construction project on schedule. The layout and cross-section of the spillway was selected with consideration given to the RCC placing operation. A lift thickness of 0.20 m was selected. A formed ogee crest consisting of conventional reinforced concrete was constructed on top of the RCC. The downstream steps of the spillway were also covered with cast-in-place concrete. A low level sluice was designed to resist the weight of the wet RCC. The design compressive strength of the RCC was 20 MPa. The forms used to support the cast-in-place facing concrete on the upstream face of the dam were constructed full height and were braced back to the downstream face of the existing concrete structure prior to the start of RCC placement. Formwork inserts were placed in the facing concrete as construction progressed. Crack inducers were pre-placed on the forms. Aggregates from a local source were transported to a pug mill as the RCC construction progressed. The RCC was spread into 0.20 m lifts using a small bull-dozer, and the facing concrete was vibrated into the lift below. RCC lifts were compacted using a 9 tonne vibratory drum roller. The RCC placing operation was completed over a period of 10 days. Following the completion of the RCC portion of the dam, the remainder of the cast-in-place concrete was completed. It was concluded that the RCC provided a durable, low-maintenance structure that was completed at a lower price and in a shorter time-frame than

  7. Introduction to international radio regulations

    Energy Technology Data Exchange (ETDEWEB)

    Radicella, S M [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)

    2003-12-15

    These lecture notes contain an overview of basic problems of the International Radio Regulations. Access to the existing information infrastructure, and to that of the future Information Society, depends critically on radio, especially in poor, remote and sparsely populated regions with under-developed telecommunication infrastructure. How the spectrum of radio frequencies is regulated has profound impact on the society, its security, prosperity, and culture. The radio regulations represent a very important framework for an adequate use of radio and should be known by all of those working in the field.

  8. Introduction to international radio regulations

    International Nuclear Information System (INIS)

    Radicella, S.M.

    2003-01-01

    These lecture notes contain an overview of basic problems of the International Radio Regulations. Access to the existing information infrastructure, and to that of the future Information Society, depends critically on radio, especially in poor, remote and sparsely populated regions with under-developed telecommunication infrastructure. How the spectrum of radio frequencies is regulated has profound impact on the society, its security, prosperity, and culture. The radio regulations represent a very important framework for an adequate use of radio and should be known by all of those working in the field

  9. MacDUST - a powder diffraction package developed for the ''ADONE'' high resolution diffraction station

    International Nuclear Information System (INIS)

    Burattini, E.; Cappuccio, G.; Maistrelli, P.; Simeoni, S.

    1993-01-01

    A High Resolution Powder Diffraction Station (PO.DI.STA.) was installed at the beginning of 1991 on the ADONE-Wiggler magnet beam line. The station and the first powder diffraction spectra, collected with synchrotron radiation, were presented at the EPDIC-1 Conference. More details can also be found in. For this station, a very sophisticated software package ''MacDUST'' has been developed on an Apple Macintosh computer, using the Microsoft QuickBASIC compiler. It allows very easy and comfortable operations by means of a graphical user interface environment, typical of the Macintosh system. The package consists of five major programs. The main program, MacDIFF, performs all the graphic operations on the experimental data, including zooming, overlapping, cursor scanning and editing of patterns, control of output operations to printers and HPGL plotters. It also includes several analysis routines for data smoothing, a first derivative peak search algorithm, two background subtraction routines and two profile fitting programs: one based on the simplex method and the other on the Marquardt modification of a least-square algorithm. MacPDF and MacRIC are both dedicated to phase identification. The first program is an archive manager for searching, displaying and printing phase records; MacRIC is a graphic aided search-match program based on the Hanawalt algorithm. Mac3-DIM is a plot program, useful, e.g., for representing kinetics three dimensionally. MacRIET is a Macintosh version of the well known Rietveld refinement program. This version, besides conventional structure refinements, also allows the determination of micro structural parameters, i.e. micro strain and crystallite size. The program can also be used to simulate a pattern, once the structure of the compound is known. Taking advantage of the very intuitive Macintosh graphic user interface, through dialog and alert boxes, the program allows straightforward introduction and modification of the structure

  10. Protocol to Exploit Waiting Resources for UASNs

    Directory of Open Access Journals (Sweden)

    Li-Ling Hung

    2016-03-01

    Full Text Available The transmission speed of acoustic waves in water is much slower than that of radio waves in terrestrial wireless sensor networks. Thus, the propagation delay in underwater acoustic sensor networks (UASN is much greater. Longer propagation delay leads to complicated communication and collision problems. To solve collision problems, some studies have proposed waiting mechanisms; however, long waiting mechanisms result in low bandwidth utilization. To improve throughput, this study proposes a slotted medium access control protocol to enhance bandwidth utilization in UASNs. The proposed mechanism increases communication by exploiting temporal and spatial resources that are typically idle in order to protect communication against interference. By reducing wait time, network performance and energy consumption can be improved. A performance evaluation demonstrates that when the data packets are large or sensor deployment is dense, the energy consumption of proposed protocol is less than that of existing protocols as well as the throughput is higher than that of existing protocols.

  11. An Energy-Efficient Link Layer Protocol for Reliable Transmission over Wireless Networks

    Directory of Open Access Journals (Sweden)

    Iqbal Adnan

    2009-01-01

    Full Text Available In multihop wireless networks, hop-by-hop reliability is generally achieved through positive acknowledgments at the MAC layer. However, positive acknowledgments introduce significant energy inefficiencies on battery-constrained devices. This inefficiency becomes particularly significant on high error rate channels. We propose to reduce the energy consumption during retransmissions using a novel protocol that localizes bit-errors at the MAC layer. The proposed protocol, referred to as Selective Retransmission using Virtual Fragmentation (SRVF, requires simple modifications to the positive-ACK-based reliability mechanism but provides substantial improvements in energy efficiency. The main premise of the protocol is to localize bit-errors by performing partial checksums on disjoint parts or virtual fragments of a packet. In case of error, only the corrupted virtual fragments are retransmitted. We develop stochastic models of the Simple Positive-ACK-based reliability, the previously-proposed Packet Length Optimization (PLO protocol, and the SRVF protocol operating over an arbitrary-order Markov wireless channel. Our analytical models show that SRVF provides significant theoretical improvements in energy efficiency over existing protocols. We then use bit-error traces collected over different real networks to empirically compare the proposed and existing protocols. These experimental results further substantiate that SRVF provides considerably better energy efficiency than Simple Positive-ACK and Packet Length Optimization protocols.

  12. Radio-capacity of ecosystems

    International Nuclear Information System (INIS)

    Kultakhmedov, Yu.; Kultakhmedova-Vyshnyakova, V.

    1997-01-01

    This paper consider a universal approach to ecosystems of different types, based on representation of their radio-capacity. The concept of ecosystem includes reproduction of components (bio-productivity) and conditions such as maintaining of environment quality. Radio-capacity in the case of radionuclide pollution appears in accumulation and redistribution of radionuclides in the ecosystem. As a result the radionuclides are redistributed and buried in soil or lake bottom sediments. Estimation models for the radio-capacity of water and terrestrial ecosystems are represented. The calculations of the radio-capacity factor of water ecosystems are performed, and the high radio-capacity of a freshwater reservoir (F=0.6-0.8) and extremely high radio-capacity of a reservoir cascade (F c =0.99) is shown material from the Dnieper's cascade reservoirs. The methods of radio-capacity estimation of agroecosystems, wood and marine ecosystems are developed. (authors)

  13. The Concept of 'Radio Music'

    DEFF Research Database (Denmark)

    Fjeldsøe, Michael

    2016-01-01

    , educational and didactic effort which would enlighten all of society. For a while it seemed that radio music was considered a genre of its own. To fulfil its function, radio music had to consider technical limitations as well as the educational level and listening modes of the new mass audience. Public radio......, as discussed by Kurt Weill and Paul Hindemith, was at first greeted with great expectations, but soon a more realistic attitude prevailed. Weill, himself a radio critic as well, composed Der Lindberghflug (1929) as a piece of ‘radio music theatre’, but then changed some of its features in order to turn...... it into a didactical play for amateurs, a so-called Lehrstück. The article will present the concept of ‘radio music’ developed within German Neue Sachlichkeit and discuss the relevance of such a concept for current research in the field of radio and music....

  14. Tools of radio astronomy

    CERN Document Server

    Wilson, Thomas L; Hüttemeister, Susanne

    2009-01-01

    The recent years have seen breathtaking progress in technology, especially in the receiver and digital technologies relevant for radio astronomy, which has at the same time advanced to shorter wavelengths. This is the updated and completely revised 5th edition of the most used introductory text in radio astronomy. It presents a unified treatment of the entire field from centimeter to sub-millimeter wavelengths. Topics covered include instruments, sensitivity considerations, observational methods and interpretations of the data recorded with both single dishes and interferometers. This text is useful to both students and experienced practicing astronomers. Besides making major updates and additions throughout the book, the authors have re-organized a number of chapters to more clearly separate basic theory from rapidly evolving practical aspects. Further, problem sets have been added at the end of each chapter.

  15. Radio telescope control

    CERN Document Server

    Schraml, J

    1972-01-01

    An on-line computer control process developed for the 100-m radio telescope of the Max-Planck-Institut fur Radioastronomie in Bonn is described. The instrument is the largest fully steerable antenna in the world. Its operation started on May 31st 1972. It is controlled by a Ferranti Argus 500 on-line computer. The first part of the paper deals with the process itself, the radio telescope and its operation, and the demands resulting for the control program. The second part briefly describes the computer and its hardware. The final part introduces the architecture of the executive program in general, which has been tailored to meet the demands of the process and the hardware. The communication between the observer and the system, the format of data on magnetic tape and an on-line reduction of position measurements are considered. (0 refs).

  16. Die radio in Afrika

    Directory of Open Access Journals (Sweden)

    S. de Villiers

    1966-03-01

    Full Text Available Omvang van radio-uitsendings in en na Afrika. — Redes vir die versnelde tempo van uitbreiding. — Radio as die geskikste massa-kommunikasiemiddel vir Afrika. — Faktore wat die verspreiding bemoeilik. — Skouspelagtige toename in luistertalle.Toe Plinius, wat in die jaar 79 oorlede is, in sy „Historia Naturalis” verklaar het dat daar altyd iets nuuts uit Afrika afkomstig is, kon hy nouliks voorsien het dat die „iets" negentien eeue later in die lug sou setel wat hierdie reuse-vasteland oorspan — ’n Babelse spraakverwarring en ’n ongekende, verbete woorde-oorlog in die etergolwe, onder meer daarop bereken om die harte en hoofde van derduisendes te verower.

  17. NOAA Weather Radio

    Science.gov (United States)

    cosas afectan la recepción de señas de la radio. Por ejemplo, las extensiones grandes de agua de sal receptor con una antena interior de calidad buena, o conectarlo a una antena externa. Generalmente los Programación Español Listado de estación Explicacion de SAME Coverage Station Listing County Listing

  18. Radio Frequency Interference Mitigation

    Science.gov (United States)

    An, T.; Chen, X.; Mohan, P.; Lao, B. Q.

    2017-09-01

    The observational facilities of radio astronomy keep constant upgrades and developments to achieve better capabilities including increasing the time of the data recording and frequency resolutions, and increasing the receiving and recording bandwidth. However in contrast, only a limited spectrum resource has been allocated to radio astronomy by the International Telecommunication Union, resulting in that the radio observational instrumentations are inevitably exposed to undesirable radio frequency interference (RFI) signals which originate mainly from the terrestrial human activity and are becoming stronger with time. RFIs degrade the quality of data and even lead to invalid data. The impact of RFIs on scientific outcome becomes more and more serious. In this article, the requirement for RFI mitigation is motivated, and the RFI characteristics, mitigation techniques, and strategies are reviewed. The mitigation strategies adopted at some representative observatories, telescopes, and arrays are also introduced. The advantages and shortcomings of the four classes of RFI mitigation strategies are discussed and presented, applicable at the connected causal stages: preventive, pre-detection, pre-correlation, and post-correlation. The proper identification and flagging of RFI is the key to the reduction of data loss and improvement in data quality, and is also the ultimate goal of developing RFI mitigation technique. This can be achieved through a strategy involving a combination of the discussed techniques in stages. The recent advances in the high speed digital signal processing and high performance computing allow for performing RFI excision of the large data volumes generated from large telescopes or arrays in both real time and offline modes, aiding the proposed strategy.

  19. AIDS radio triggers.

    Science.gov (United States)

    Elias, A M

    1991-07-01

    In April 1991, the Ethnic Communities' Council of NSW was granted funding under the Community AIDS Prevention and Education Program through the Department of Community Services and Health, to produce a series of 6x50 second AIDS radio triggers with a 10-second tag line for further information. The triggers are designed to disseminate culturally-sensitive information about HIV/AIDS in English, Italian, Greek, Spanish, Khmer, Turkish, Macedonian, Serbo-Croatian, Arabic, Cantonese, and Vietnamese, with the goal of increasing awareness and decreasing the degree of misinformation about HIV/AIDS among people of non-English-speaking backgrounds through radio and sound. The 6 triggers cover the denial that AIDS exists in the community, beliefs that words and feelings do not protect one from catching HIV, encouraging friends to be compassionate, compassion within the family, AIDS information for a young audience, and the provision of accurate and honest information on HIV/AIDS. The triggers are slated to be completed by the end of July 1991 and will be broadcast on all possible community, ethnic, and commercial radio networks across Australia. They will be available upon request in composite form with an information kit for use by health care professionals and community workers.

  20. Directional MAC approach for wireless body area networks.

    Science.gov (United States)

    Hussain, Md Asdaque; Alam, Md Nasre; Kwak, Kyung Sup

    2011-01-01

    Wireless Body Area Networks (WBANs) designed for medical, sports, and entertainment applications, have drawn the attention of academia and industry alike. A WBAN is a special purpose network, designed to operate autonomously to connect various medical sensors and appliances, located inside and/or outside of a human body. This network enables physicians to remotely monitor vital signs of patients and provide real time feedback for medical diagnosis and consultations. The WBAN system can offer two significant advantages: patient mobility due to their use of portable monitoring devices and a location independent monitoring facility. With its appealing dimensions, it brings about a new set of challenges, which we do not normally consider in such small sensor networks. It requires a scalable network in terms of heterogeneous data traffic, low power consumption of sensor nodes, integration in and around the body networking and coexistence. This work presents a medium access control protocol for WBAN which tries to overcome the aforementioned challenges. We consider the use of multiple beam adaptive arrays (MBAA) at BAN Coordinator (BAN_C) node. When used as a BAN_C, an MBAA can successfully receive two or more overlapping packets at the same time. Each beam captures a different packet by automatically pointing its pattern toward one packet while annulling other contending packets. This paper describes how an MBAA can be integrated into a single hope star topology as a BAN_C. Simulation results show the performance of our proposed protocol.

  1. Directional MAC Approach for Wireless Body Area Networks

    Directory of Open Access Journals (Sweden)

    Md. Asdaque Hussain

    2011-01-01

    Full Text Available Wireless Body Area Networks (WBANs designed for medical, sports, and entertainment applications, have drawn the attention of academia and industry alike. A WBAN is a special purpose network, designed to operate autonomously to connect various medical sensors and appliances, located inside and/or outside of a human body. This network enables physicians to remotely monitor vital signs of patients and provide real time feedback for medical diagnosis and consultations. The WBAN system can offer two significant advantages: patient mobility due to their use of portable monitoring devices and a location independent monitoring facility. With its appealing dimensions, it brings about a new set of challenges, which we do not normally consider in such small sensor networks. It requires a scalable network in terms of heterogeneous data traffic, low power consumption of sensor nodes, integration in and around the body networking and coexistence. This work presents a medium access control protocol for WBAN which tries to overcome the aforementioned challenges. We consider the use of multiple beam adaptive arrays (MBAA at BAN Coordinator (BAN_C node. When used as a BAN_C, an MBAA can successfully receive two or more overlapping packets at the same time. Each beam captures a different packet by automatically pointing its pattern toward one packet while annulling other contending packets. This paper describes how an MBAA can be integrated into a single hope star topology as a BAN_C. Simulation results show the performance of our proposed protocol.

  2. Outside-In Signal Transmission by Conformational Changes in Integrin Mac-11

    Science.gov (United States)

    Lefort, Craig T.; Hyun, Young-Min; Schultz, Joanne B.; Law, Foon-Yee; Waugh, Richard E.; Knauf, Philip A.; Kim, Minsoo

    2010-01-01

    Intracellular signals associated with or triggered by integrin ligation can control cell survival, differentiation, proliferation, and migration. Despite accumulating evidence that conformational changes regulate integrin affinity to its ligands, how integrin structure regulates signal transmission from the outside to the inside of the cell remains elusive. Using fluorescence resonance energy transfer, we addressed whether conformational changes in integrin Mac-1 are sufficient to transmit outside-in signals in human neutrophils. Mac-1 conformational activation induced by ligand occupancy or activating Ab binding, but not integrin clustering, triggered similar patterns of intracellular protein tyrosine phosphorylation, including Akt phosphorylation, and inhibited spontaneous neutrophil apoptosis, indicating that global conformational changes are critical for Mac-1-dependent outside-in signal transduction. In neutrophils and myeloid K562 cells, ligand ICAM-1 or activating Ab binding promoted switchblade-like extension of the Mac-1 extracellular domain and separation of the αM and β2 subunit cytoplasmic tails, two structural hallmarks of integrin activation. These data suggest the primacy of global conformational changes in the generation of Mac-1 outside-in signals. PMID:19864611

  3. Eliminating the Heart from the Curcumin Molecule: Monocarbonyl Curcumin Mimics (MACs)

    Science.gov (United States)

    Shetty, Dinesh; Kim, Yong Joon; Shim, Hyunsuk; Snyder, James P.

    2015-01-01

    Curcumin is a natural product with several thousand years of heritage. Its traditional Asian application to human ailments has been subjected in recent decades to worldwide pharmacological, biochemical and clinical investigations. Curcumin’s Achilles heel lies in its poor aqueous solubility and rapid degradation at pH ~ 7.4. Researchers have sought to unlock curcumin’s assets by chemical manipulation. One class of molecules under scrutiny are the monocarbonyl analogs of curcumin (MACs). A thousand plus such agents have been created and tested primarily against cancer and inflammation. The outcome is clear. In vitro, MACs furnish a 10–20 fold potency gain vs. curcumin for numerous cancer cell lines and cellular proteins. Similarly, MACs have successfully demonstrated better pharmacokinetic (PK) profiles in mice and greater tumor regression in cancer xenografts in vivo than curcumin. The compounds reveal limited toxicity as measured by murine weight gain and histopathological assessment. To our knowledge, MAC members have not yet been monitored in larger animals or humans. However, Phase 1 clinical trials are certainly on the horizon. The present review focuses on the large and evolving body of work in cancer and inflammation, but also covers MAC structural diversity and early discovery for treatment of bacteria, tuberculosis, Alzheimer’s disease and malaria. PMID:25547726

  4. Crystallization and preliminary X-ray crystallographic analysis of MacA from Actinobacillus actinomycetemcomitans

    International Nuclear Information System (INIS)

    Piao, Shunfu; Xu, Yongbin; Ha, Nam-Chul

    2008-01-01

    A periplasmic membrane-fusion protein MacA from Actinobacillus actinomycetemcomitans, an essential component of the multidrug efflux pump in Gram-negative bacteria, was crystallized. Periplasmic membrane-fusion proteins (MFPs) are an essential component of the multidrug efflux pump in Gram-negative bacteria. They play a crucial role in bridging the outer membrane porin TolC and two distinct types of inner membrane transporters. The MFP MacA bridges the inner membrane ABC-type multidrug transporter MacB and the outer membrane porin TolC. MacA from the pathogenic bacterium Actinobacillus actinomycetemcomitans was expressed in Escherichia coli B834 (DE3) and the recombinant protein was purified using Ni–NTA affinity, Q anion-exchange and gel-filtration chromatography. The purified MacA protein was crystallized using the vapour-diffusion method. A MAD diffraction data set was collected to a resolution of 3.0 Å at 100 K. The crystal belongs to space group P622, with unit-cell parameters a = b = 109.2, c = 255.4 Å, α = β = 90, γ = 120°, and contains one molecule in the asymmetric unit

  5. Eliminating the Heart from the Curcumin Molecule: Monocarbonyl Curcumin Mimics (MACs

    Directory of Open Access Journals (Sweden)

    Dinesh Shetty

    2014-12-01

    Full Text Available Curcumin is a natural product with several thousand years of heritage. Its traditional Asian application to human ailments has been subjected in recent decades to worldwide pharmacological, biochemical and clinical investigations. Curcumin’s Achilles heel lies in its poor aqueous solubility and rapid degradation at pH ~ 7.4. Researchers have sought to unlock curcumin’s assets by chemical manipulation. One class of molecules under scrutiny are the monocarbonyl analogs of curcumin (MACs. A thousand plus such agents have been created and tested primarily against cancer and inflammation. The outcome is clear. In vitro, MACs furnish a 10–20 fold potency gain vs. curcumin for numerous cancer cell lines and cellular proteins. Similarly, MACs have successfully demonstrated better pharmacokinetic (PK profiles in mice and greater tumor regression in cancer xenografts in vivo than curcumin. The compounds reveal limited toxicity as measured by murine weight gain and histopathological assessment. To our knowledge, MAC members have not yet been monitored in larger animals or humans. However, Phase 1 clinical trials are certainly on the horizon. The present review focuses on the large and evolving body of work in cancer and inflammation, but also covers MAC structural diversity and early discovery for treatment of bacteria, tuberculosis, Alzheimer’s disease and malaria.

  6. Crystallization and preliminary X-ray crystallographic analysis of MacA from Actinobacillus actinomycetemcomitans

    Energy Technology Data Exchange (ETDEWEB)

    Piao, Shunfu; Xu, Yongbin; Ha, Nam-Chul, E-mail: hnc@pusan.ac.kr [College of Pharmacy and Research Institute for Drug Development, Pusan National University, Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of)

    2008-05-01

    A periplasmic membrane-fusion protein MacA from Actinobacillus actinomycetemcomitans, an essential component of the multidrug efflux pump in Gram-negative bacteria, was crystallized. Periplasmic membrane-fusion proteins (MFPs) are an essential component of the multidrug efflux pump in Gram-negative bacteria. They play a crucial role in bridging the outer membrane porin TolC and two distinct types of inner membrane transporters. The MFP MacA bridges the inner membrane ABC-type multidrug transporter MacB and the outer membrane porin TolC. MacA from the pathogenic bacterium Actinobacillus actinomycetemcomitans was expressed in Escherichia coli B834 (DE3) and the recombinant protein was purified using Ni–NTA affinity, Q anion-exchange and gel-filtration chromatography. The purified MacA protein was crystallized using the vapour-diffusion method. A MAD diffraction data set was collected to a resolution of 3.0 Å at 100 K. The crystal belongs to space group P622, with unit-cell parameters a = b = 109.2, c = 255.4 Å, α = β = 90, γ = 120°, and contains one molecule in the asymmetric unit.

  7. MAP, MAC, and vortex-rings configurations in the Weinberg-Salam model

    Science.gov (United States)

    Teh, Rosy; Ng, Ban-Loong; Wong, Khai-Ming

    2015-11-01

    We report on the presence of new axially symmetric monopoles, antimonopoles and vortex-rings solutions of the SU(2)×U(1) Weinberg-Salam model of electromagnetic and weak interactions. When the ϕ-winding number n = 1, and 2, the configurations are monopole-antimonopole pair (MAP) and monopole-antimonopole chain (MAC) with poles of alternating sign magnetic charge arranged along the z-axis. Vortex-rings start to appear from the MAP and MAC configurations when the winding number n = 3. The MAP configurations possess zero net magnetic charge whereas the MAC configurations possess net magnetic charge of 4 πn / e. In the MAP configurations, the monopole-antimonopole pair is bounded by the Z0 field flux string and there is an electromagnetic current loop encircling it. The monopole and antimonopole possess magnetic charges ± 4πn/e sin2θW respectively. In the MAC configurations there is no string connecting the monopole and the adjacent antimonopole and they possess magnetic charges ± 4 πn/e respectively. The MAC configurations possess infinite total energy and zero magnetic dipole moment whereas the MAP configurations which are actually sphalerons possess finite total energy and magnetic dipole moment. The configurations were investigated for varying values of Higgs self-coupling constant 0 ≤ λ ≤ 40 at Weinberg angle θW = π/4.

  8. Beyond protocols

    DEFF Research Database (Denmark)

    Vanderhoeven, Sonia; Branquart, Etienne; Casaer, Jim

    2017-01-01

    Risk assessment tools for listing invasive alien species need to incorporate all available evidence and expertise. Beyond the wealth of protocols developed to date, we argue that the current way of performing risk analysis has several shortcomings. In particular, lack of data on ecological impact...... information on risk and the exploration of improved methods for decision making on biodiversity management. This is crucial for efficient conservation resource allocation and uptake by stakeholders and the public......., transparency and repeatability of assessments as well as the incorporation of uncertainty should all be explicitly considered. We recommend improved quality control of risk assessments through formalized peer review with clear feedback between assessors and reviewers. Alternatively, a consensus building...

  9. Detection of constitutive heterodimerization of the integrin Mac-1 subunits by fluorescence resonance energy transfer in living cells

    International Nuclear Information System (INIS)

    Fu Guo; Yang Huayan; Wang Chen; Zhang Feng; You Zhendong; Wang Guiying; He Cheng; Chen Yizhang; Xu Zhihan

    2006-01-01

    Macrophage differentiation antigen associated with complement three receptor function (Mac-1) belongs to β 2 subfamily of integrins that mediate important cell-cell and cell-extracellular matrix interactions. Biochemical studies have indicated that Mac-1 is a constitutive heterodimer in vitro. Here, we detected the heterodimerization of Mac-1 subunits in living cells by means of two fluorescence resonance energy transfer (FRET) techniques (fluorescence microscopy and fluorescence spectroscopy) and our results demonstrated that there is constitutive heterodimerization of the Mac-1 subunits and this constitutive heterodimerization of the Mac-1 subunits is cell-type independent. Through FRET imaging, we found that heterodimers of Mac-1 mainly localized in plasma membrane, perinuclear, and Golgi area in living cells. Furthermore, through analysis of the estimated physical distances between cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) fused to Mac-1 subunits, we suggested that the conformation of Mac-1 subunits is not affected by the fusion of CFP or YFP and inferred that Mac-1 subunits take different conformation when expressed in Chinese hamster ovary (CHO) and human embryonic kidney (HEK) 293T cells, respectively

  10. Microcrystallography, high-pressure cryocooling and BioSAXS at MacCHESS

    Energy Technology Data Exchange (ETDEWEB)

    Englich, Ulrich, E-mail: ue22@cornell.edu; Kriksunov, Irina A. [MacCHESS (Macromolecular Diffraction Facility at CHESS), Cornell University, Ithaca, NY 14853 (United States); Cerione, Richard A. [MacCHESS (Macromolecular Diffraction Facility at CHESS), Cornell University, Ithaca, NY 14853 (United States); Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853 (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States); Cook, Michael J.; Gillilan, Richard [MacCHESS (Macromolecular Diffraction Facility at CHESS), Cornell University, Ithaca, NY 14853 (United States); Gruner, Sol M. [Field of Biophysics, Cornell University, Ithaca, NY 14853 (United States); Physics Department, Cornell University, Ithaca, NY 14853 (United States); Huang, Qingqui; Kim, Chae Un; Miller, William; Nielsen, Soren; Schuller, David; Smith, Scott; Szebenyi, Doletha M. E. [MacCHESS (Macromolecular Diffraction Facility at CHESS), Cornell University, Ithaca, NY 14853 (United States)

    2011-01-01

    Three research initiatives pursued by the Macromolecular Diffraction Facility at the Cornell High Energy Synchrotron Source (MacCHESS) are presented. The Macromolecular Diffraction Facility at the Cornell High Energy Synchrotron Source (MacCHESS) is a national research resource supported by the National Center for Research Resources of the US National Institutes of Health. MacCHESS is pursuing several research initiatives designed to benefit both CHESS users and the wider structural biology community. Three initiatives are presented in further detail: microcrystallography, which aims to improve the collection of diffraction data from crystals a few micrometers across, or small well diffracting regions of inhomogeneous crystals, so as to obtain high-resolution structures; pressure cryocooling, which can stabilize transient structures and reduce lattice damage during the cooling process; and BioSAXS (small-angle X-ray scattering on biological solutions), which can extract molecular shape and other structural information from macromolecules in solution.

  11. Learn Objective-C on the Mac for OS X and iOS

    CERN Document Server

    Knaster, Scott; Malik, Waqar

    2012-01-01

    Learn to write apps for some of today's hottest technologies, including the iPhone and iPad (using iOS), as well as the Mac (using OS X). It starts with Objective-C, the base language on which the native iOS software development kit (SDK) and the OS X are based. Learn Objective-C on the Mac: For OS X and iOS, Second Edition updates a best selling book and is an extensive, newly updated guide to Objective-C. Objective-C is a powerful, object-oriented extension of C, making this update the perfect follow-up to Dave Mark's bestselling Learn C on the Mac. Whether you're an experienced C programmer

  12. Side channel analysis of some hash based MACs:A response to SHA-3 requirements

    DEFF Research Database (Denmark)

    The forthcoming NIST's Advanced Hash Standard (AHS) competition to select SHA-3 hash function requires that each candidate hash function submission must have at least one construction to support FIPS 198 HMAC application. As part of its evaluation, NIST is aiming to select either a candidate hash...... function which is more resistant to known side channel attacks (SCA) when plugged into HMAC, or that has an alternative MAC mode which is more resistant to known SCA than the other submitted alternatives. In response to this, we perform differential power analysis (DPA) on the possible smart card...... implementations of some of the recently proposed MAC alternatives to NMAC (a fully analyzed variant of HMAC) and HMAC algorithms and NMAC/HMAC versions of some recently proposed hash and compression function modes. We show that the recently proposed BNMAC and KMDP MAC schemes are even weaker than NMAC...

  13. Macular telangiectasia type 2 (MacTel) in a 34-year-old patient.

    Science.gov (United States)

    Nicolai, Heleen; Wirix, Mieke; Spielberg, Leigh; Leys, Anita

    2014-09-23

    We report macular telangiectasia type 2 (MacTel) in a 34-year-old man, the youngest patient so far published with MacTel type 2. The patient presented with metamorphopsia and impaired reading ability. Diagnosis was based on bilateral abnormal macular autofluorescence, perifoveal telangiectasia with fluorescein angiographic hyperfluorescence without cystoid oedema, a small foveal avascular zone, asymmetric configuration of the foveal pit, disruptions in the inner segment/outer segment layer and hyper-reflective haze and spots in the outer nuclear layer. Although MacTel usually manifests with a slowly progressive decrease in visual acuity in the fifth to seventh decades of life, younger patients may occasionally be diagnosed with the disease. Awareness of subtle signs of the condition is essential for early diagnosis. 2014 BMJ Publishing Group Ltd.

  14. Design And Implementation Of Radio Resources Controller Of WCDMA

    International Nuclear Information System (INIS)

    Hafez, A.M.A.

    2012-01-01

    Recently, wireless communications and especially the mobile networks are employed in nuclear applications including, but not limited to, Nuclear Material Integrity [1], Radiation Monitoring Networks [2, 3] and Nuclear Power Plants [4]. The thesis introduces an overview about one of the third generation (3G) mobile networks, known as Universal Mobile Telecommunications System (UMTS) networks, which consists of Universal Terrestrial Radio Access Network (UTRAN) and the Core Network (CN). The UTRAN has many interfaces, but the thesis focuses on the Uu interface which is between the User Equipment (UE) and the UTRAN. That interface is based on Wideband Code Division Multiple Accessing (WCDMA) system. The protocol architecture of UMTS is composed of two planes; the control plane and the user plane. Again, the thesis is concerned on the control plane which has the Radio Resources Control (RRC) protocol to manage the control signal at the Uu interface between the UE and the Radio Network Controller. The main goal of the thesis is to design, implement and test the building blocks of Radio Resources Controller of the WCDMA system. Also, the thesis presents one of nuclear applications that is based on WCDMA. This application includes design, implementation and simulation of Radiation Monitoring network as a pilot prototype model.

  15. LFA-1 and Mac-1 integrins bind to the serine/threonine-rich domain of thrombomodulin

    Energy Technology Data Exchange (ETDEWEB)

    Kawamoto, Eiji [Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 (Japan); Emergency and Critical Care Center, Mie University Hospital, 2-174 Edobashi, Tsu 514-8507 (Japan); Okamoto, Takayuki, E-mail: okamotot@doc.medic.mie-u.ac.jp [Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 (Japan); Takagi, Yoshimi [Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 (Japan); Honda, Goichi [Medical Affairs Department, Asahi Kasei Pharma Corporation, 1-105 Kanda Jinbo-cho, Chiyoda-ku, Tokyo 101-8101 (Japan); Suzuki, Koji [Faculty of Pharmaceutical Science, Suzuka University of Medical Science, 3500-3, Minamitamagaki-cho, Suzuka, Mie 513-8679 (Japan); Imai, Hiroshi [Emergency and Critical Care Center, Mie University Hospital, 2-174 Edobashi, Tsu 514-8507 (Japan); Shimaoka, Motomu, E-mail: shimaoka@doc.medic.mie-u.ac.jp [Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507 (Japan)

    2016-05-13

    LFA-1 (αLβ2) and Mac-1 (αMβ2) integrins regulate leukocyte trafficking in health and disease by binding primarily to IgSF ligand ICAM-1 and ICAM-2 on endothelial cells. Here we have shown that the anti-coagulant molecule thrombomodulin (TM), found on the surface of endothelial cells, functions as a potentially new ligand for leukocyte integrins. We generated a recombinant extracellular domain of human TM and Fc fusion protein (TM-domains 123-Fc), and showed that pheripheral blood mononuclear cells (PBMCs) bind to TM-domains 123-Fc dependent upon integrin activation. We then demonstrated that αL integrin-blocking mAb, αM integrin-blocking mAb, and β2 integrin-blocking mAb inhibited the binding of PBMCs to TM-domains 123-Fc. Furthermore, we show that the serine/threonine-rich domain (domain 3) of TM is required for the interaction with the LFA-1 (αLβ2) and Mac-1 (αMβ2) integrins to occur on PBMCs. These results demonstrate that the LFA-1 and Mac-1 integrins on leukocytes bind to TM, thereby establishing the molecular and structural basis underlying LFA-1 and Mac-1 integrin interaction with TM on endothelial cells. In fact, integrin-TM interactions might be involved in the dynamic regulation of leukocyte adhesion with endothelial cells. - Highlights: • LFA-1 and Mac-1 integrins bind to the anti-coagulant molecule thrombomodulin. • The serine/threonine-rich domain of thrombomodulin is essential to interact with the LFA-1 and Mac-1 integrins on PBMCs. • Integrin-TM interactions might be involved in the dynamic regulation of leukocyte adhesion with endothelial cells.

  16. Conformational stability analyses of alpha subunit I domain of LFA-1 and Mac-1.

    Directory of Open Access Journals (Sweden)

    Debin Mao

    Full Text Available β₂ integrin of lymphocyte function-associated antigen-1 (LFA-1 or macrophage-1 antigen (Mac-1 binds to their common ligand of intercellular adhesion molecule-1 (ICAM-1 and mediates leukocyte-endothelial cell (EC adhesions in inflammation cascade. Although the two integrins are known to have distinct functions, the corresponding micro-structural bases remain unclear. Here (steered-molecular dynamics simulations were employed to elucidate the conformational stability of α subunit I domains of LFA-1 and Mac-1 in different affinity states and relevant I domain-ICAM-1 interaction features. Compared with low affinity (LA Mac-1, the LA LFA-1 I domain was unstable in the presence or absence of ICAM-1 ligand, stemming from diverse orientations of its α₇-helix with different motifs of zipper-like hydrophobic junction between α₁- and α₇-helices. Meanwhile, spontaneous transition of LFA-1 I domain from LA state to intermediate affinity (IA state was first visualized. All the LA, IA, and high affinity (HA states of LFA-1 I domain and HA Mac-1 I domain were able to bind to ICAM-1 ligand effectively, while LA Mac-1 I domain was unfavorable for binding ligand presumably due to the specific orientation of S144 side-chain that capped the MIDAS ion. These results furthered our understanding in correlating the structural bases with their functions of LFA-1 and Mac-1 integrins from the viewpoint of I domain conformational stability and of the characteristics of I domain-ICAM-1 interactions.

  17. Flexible Adaptation in Cognitive Radios

    CERN Document Server

    Li, Shujun

    2013-01-01

    This book provides an introduction to software-defined radio and cognitive radio, along with methodologies for applying knowledge representation, semantic web, logic reasoning and artificial intelligence to cognitive radio, enabling autonomous adaptation and flexible signaling. Readers from the wireless communications and software-defined radio communities will use this book as a reference to extend software-defined radio to cognitive radio, using the semantic technology described. Readers with a background in semantic web and artificial intelligence will find in this book the application of semantic web and artificial intelligence technologies to wireless communications. For readers in networks and network management, this book presents a new approach to enable interoperability, collaborative optimization and flexible adaptation of network components. Provides a comprehensive ontology covering the core concepts of wireless communications using a formal language; Presents the technical realization of using a ...

  18. Adherence Evaluation of a MacPherson Suspension under EuSAMA Norm in a Mathematical Model and one Multibody

    Directory of Open Access Journals (Sweden)

    Juan J. Arbeláez-Toro

    2013-11-01

    Full Text Available A computational simulation is Implemented, in order to response to a problem of dynamics associated With The assessment of adherence in suspension systems. The process begins with the lifting of the most representative geometries of a MacPherson system of a Nissan Sentra B13, where each of the devices is created and assembled into a CAD software to give a dynamic solution on a CAE multibody package. Afterwards a mathematical model was created whose differential equations are generated substantiated on Newton's second law and this are resolved using Matlab-Simulink applications. Once the model developing process is over, the variables are fed with accurate information of the studied vehicle to obtain the graphs that give an answer to EuSAMA (European Shock Absorber Manufacturers Association test protocol for the adherence analysis. The results presented show the reliability of the developed models when compared with the experimental test; furthermore, it demonstrates that the decrease of the damping coefficient compromises the vehicle´s adherence on the track, affecting its stability and maneuverability.

  19. Processo de adaptação da bateria Montreal de avaliação da comunicação: bateria MAC - ao português brasileiro Adaptation process to Brazilian Portuguese of the Montreal communication evaluation battery: MAC battery

    Directory of Open Access Journals (Sweden)

    Rochele Paz Fonseca

    2007-01-01

    Full Text Available O presente estudo tem por objetivo apresentar a adaptação do "Protocole Montréal d'Évaluation de la Communication - Protocole MEC" (Bateria Montreal de Avaliação da Comunicação - Bateria MAC ao Português Brasileiro. Esta bateria canadense foi construída para avaliar quatro processamentos comunicativos de ativação do hemisfério direito: discursivo, pragmático-inferencial, léxico-semântico e prosódico. Participaram do estudo seis tradutores, três juízes especialistas, 54 juízes não-especialistas e 16 participantes dos estudos piloto. Os procedimentos gerais promovidos foram tradução, análise de critérios psicolingüísticos por juízes e aplicação do instrumento em estudos piloto. As tarefas Interpretação de metáforas, Discurso narrativo e Julgamento semântico exigiram um processo de adaptação mais complexo e rigoroso. Com base em critérios psicolingüísticos, realizaram-se algumas mudanças nos estímulos, com a finalidade principal de manutenção do objetivo de cada tarefa do instrumento original. Este instrumento neuropsicológico pode ser uma ferramenta de avaliação da comunicação de indivíduos com lesão de hemisfério direito, lesão frontal, traumatismo crânio-encefálico e demência.This research aims to present the adaptation of the "Protocole Montréal d'Évaluation de la Communication - Protocole MEC" (Montreal Communication Evaluation Battery - MAC Battery to Brazilian Portuguese, in accordance with psycholinguistics criteria. MAC Battery is a Canadian instrument constructed to evaluate right hemisphere communicative and linguistic abilities, considering four processing domains: discoursive, pragmatic-inferential, lexical-semantic and prosodic. The participants were six translators, three specialist judges, 54 non-specialist judges and 16 subjects from pilot studies. Adaptation procedures included translation, judge analysis of psycholinguistics criteria and two pilot tests. Some tasks required

  20. High-contrast MacNeille-PBS-based LCOS projection systems

    Science.gov (United States)

    Chen, Jianmin; Robinson, Michael G.; Sharp, Gary D.

    2005-04-01

    Contrast limits are investigated for MacNeille PBS based LCOS projection systems that use retarder stack filters (RSF). The two contributing factors are considered separately; namely the color management system and the panel port. To enhance performance of the former, skew ray compensated RSFs are introduced. For the latter, a general methodology is presented to optimize contrast by compensating the LCOS panel. It is shown that the orientation of the LCOS panel and compensator, relative to the MacNeille PBS, is critical. The significant impact of AR coating performance on system contrast is also revealed. A high contrast architecture will be presented by way of example.

  1. The MacNew Heart Disease health-related quality of life instrument: A summary

    Directory of Open Access Journals (Sweden)

    Guyatt Gordon

    2004-01-01

    Full Text Available Abstract Background The measurement of health, the effects of disease, and the impact of health care include not only an indication of changes in disease frequency and severity but also an estimate of patients' perception of health status before and after treatment. One of the more important developments in health care in the past decade may be the recognition that the patient's perspective is as legitimate and valid as the clinician's in monitoring health care outcomes. This has lead to the development of instruments to quantify the patients' perception of their health status before and after treatment. Methods We review evidence supporting the measurement properties of the MacNew Heart Disease Health-related Quality of Life [MacNew] Questionnaire which was designed to evaluate how daily activities and physical, emotional, and social functioning are affected by coronary heart disease and its treatment. Results Reliability was demonstrated by using internal consistency and the intraclass correlation coefficients for the three domains in the Dutch, English, Farsi, German, and Spanish versions of the MacNew. With internal consistency and intraclass correlation coefficients =>0.73, reliability is high. Validity of the MacNew was examined with factor analysis and three core underlying factors, physical, emotional, and social, were identified, explaining 63.0 – 66.5% of the observed variance and replicated in the translations with psychometric data. Construct validity of the MacNew was further demonstrated by extensive substantiation of the logical relationships, defined a priori, between items and other comparison tools. The MacNew is responsive and sensitive to changes in HRQL following various interventions for patients with heart disease with 11 of 13 effect size statistics >0.80. Taking an average of 10 minutes or less to complete, the respondent-burden for the MacNew is low and its acceptability is demonstrated by response rates of over 90

  2. Learn Xcode Tools for Mac OS X and iPhone Development

    CERN Document Server

    Piper, I

    2010-01-01

    This book will give you a thorough grounding in the principal and supporting tools and technologies that make up the Xcode Developer Tools suite. Apple has provided a comprehensive collection of developer tools, and this is the first book to examine the complete Apple programming environment for both Mac OS X and iPhone. * Comprehensive coverage of all the Xcode developer tools * Additional coverage of useful third-party development tools* Not just a survey of features, but a serious examination of the complete development process for Mac OS X and iPhone applications What you'll learn* The boo

  3. Burgernomics: a big MacT guide to purchasing power parity

    OpenAIRE

    Michael R. Pakko; Patricia S. Pollard

    2003-01-01

    The theory of purchasing power parity (PPP) has long been a staple of international economic analysis. Recent years have seen the rise in popularity of a tongue-in-cheek, fast-food version of PPP: The Big Mac™ index. In this article, Michael Pakko and Patricia Pollard describe how comparisons of Big Mac prices around the world contain the ingredients necessary to demonstrate the fundamental principles of PPP. They show that the Big Mac index does nearly as well as more comprehensive measures ...

  4. Using The Economist’s Big Mac Index for Instruction

    OpenAIRE

    Stegelin, Forrest E.

    2012-01-01

    The Economist first launched the concept of the Big Mac Index in 1986 as a guide to whether currencies were at their correct exchange rate; it is not intended to be a precise predictor of currency movements around the globe, but simply a way to make exchange-rate theory and discussions a bit more digestible. First used as a humorous illustration, the term “burgernomics†was coined and the Big Mac index became an annual occurrence. It is based upon one of the oldest concepts in internationa...

  5. CoCoMac 2.0 and the future of tract-tracing databases

    OpenAIRE

    Rembrandt eBakker; Rembrandt eBakker; Rembrandt eBakker; Thomas eWachtler; Markus eDiesmann; Markus eDiesmann; Markus eDiesmann

    2012-01-01

    The CoCoMac database contains the results of published axonal tract-tracing studies in the macaque brain. The combined data are used to construct the macaque macro-connectome. We discuss the redevelopment of CoCoMac and compare it to six connectome-related projects: two resources that provide online access to raw tracing data in rodents, a connectome viewer for advanced 3d graphics, a partial but highly detailed rat connectome, a brain data management system that generates custom connectivity...

  6. The Mac'OS X command line Unix under the hood

    CERN Document Server

    McElhearn, Kirk

    2006-01-01

    The Mac command line offers a faster, easier way to accomplish many tasks. It''s also the medium for many commands that aren''t accessible using the GUI. The Mac OS X Command Line is a clear, concise, tutorial-style introduction to all the major functionality provided by the command line. It''s also packed with information the experienced users need, including little-known shortcuts and several chapters devoted to advanced topics. This is a book to get you started, but also a book you won't soon outgrow.

  7. A Critique of MacIntyrean Morality From a Kantian Perspective

    Directory of Open Access Journals (Sweden)

    Krishna Mani Pathak

    2014-04-01

    Full Text Available This article is a critical examination of MacIntyre’s notion of morality in reference to Kant’s deontological moral theory. The examination shows that MacIntyre (a criticizes Kant’s moral theory to defend virtue ethics or neo-Aristotelian ethics with a weak notion of morality; (b favors the idea of local morality, which does not leave any room for moral assessment and reciprocity in an intercultural domain; and (c fails to provide good arguments for his moral historicism and against Kant’s moral universalism.

  8. The properties of radio ellipticals

    International Nuclear Information System (INIS)

    Sparks, W.B.; Disney, M.J.; Rodgers, A.W.

    1984-01-01

    Optical and additional radio data are presented for the bright galaxies of the Disney and Wall survey (1977 Mon. Not. R. Astron. Soc. 179, 235). These data form the basis of a statistical comparison of the properties of radio elliptical galaxies to radio-quiet ellipticals. The correlations may be explained by the depth of the gravitational potential well in which the galaxy resides governing the circumstances under which an elliptical galaxy rids itself of internally produced gas. (author)

  9. A secure RFID mutual authentication protocol for healthcare environments using elliptic curve cryptography.

    Science.gov (United States)

    Jin, Chunhua; Xu, Chunxiang; Zhang, Xiaojun; Zhao, Jining

    2015-03-01

    Radio Frequency Identification(RFID) is an automatic identification technology, which can be widely used in healthcare environments to locate and track staff, equipment and patients. However, potential security and privacy problems in RFID system remain a challenge. In this paper, we design a mutual authentication protocol for RFID based on elliptic curve cryptography(ECC). We use pre-computing method within tag's communication, so that our protocol can get better efficiency. In terms of security, our protocol can achieve confidentiality, unforgeability, mutual authentication, tag's anonymity, availability and forward security. Our protocol also can overcome the weakness in the existing protocols. Therefore, our protocol is suitable for healthcare environments.

  10. Central radio sources

    International Nuclear Information System (INIS)

    Phinney, E.S.

    1985-01-01

    The compact radio sources in the nuclei of most active galaxies lie closer to their centers of activity than any other region accessible to observation, excepting only the broad emission line region. They provide uniquely strong evidence for bulk motion of matter at relativistic velocities, encouraging the belief that the activity originates in a gravitational potential well whose escape velocity is of the order of the speed of light. The observational facts are reviewed as well as several theoretical pictures of them. Those places where systematic observations could help to distinguish the true theoretical picture from the many competing forgeries are emphasized. 76 references

  11. Radio Frequency Anechoic Chamber Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Supports the design, manufacture, and test of antenna systems. The facility is also used as an electromagnetic compatibility/radio frequency interference...

  12. The Hartebeeshoek Radio Astronomy Observatory

    International Nuclear Information System (INIS)

    Nicolson, G.D.

    1986-01-01

    This article briefly discusses the questions, problems and study fields of the modern astronomer. Radioastronomy has made important contributions to the study of the evolution of stars and has given much information on the birth of stars while at the other extreme, studies of neutron stars and the radio emission from the remnants of supernova explosions have given further insight into the death of individual stars. Radio astronomical studies have learned astronomers much about the structure of the Milky way and some twenty years ago, in a search for new radio galaxies, quasars were discovered. Radioastronomy research in South Africa is carried out at the Hartebeesthoek Radio Astronomy Observatory

  13. Dramatugi Penyiar Radio

    Directory of Open Access Journals (Sweden)

    Hastika Yanti Nora

    2009-07-01

    Full Text Available Dramaturgy is the work of Erving Goffman. He wrote "Presentation of Self in Everyday Life" in '1959. Following the theatrical analogy, Goffman spoke of a front stage and back stage. The front stage is that part of the performance that generally functions in rather fixed and general ways to define the situation for those who observed the performance. The back stage is situation where facts suppressed in the front or various kinds of informal actions may appear. A back stage is usually adjacent to the front stage, but it also cut off from it. Everyone in this world have to run his role in their everyday life. It also a radio announcer. As an actor, they have to be a nice and friendy person when they perform to make air personality, that is  a good  impression, from their audience. But before their perform in the front stage, there so much to do to prepare in the backstage. The front and back stage is radio announcer dramaturgy.

  14. On the Secrecy Capacity of 5G New Radio Networks

    Directory of Open Access Journals (Sweden)

    Ke Xiao

    2018-01-01

    Full Text Available The new radio technology for the fifth-generation wireless system has been extensively studied all over the world. Specifically, the air interface protocols for 5G radio access network will be standardized by the 3GPP in the coming years. In the next-generation 5G new radio (NR networks, millimeter wave (mmWave communications will definitely play a critical role, as new NR air interface (AI is up to 100 GHz just like mmWave. The rapid growth of mmWave systems poses a variety of challenges in physical layer (PHY security. This paper investigates those challenges in the context of several 5G new radio communication technologies, including multiple-input multiple-output (MIMO and nonorthogonal multiple access (NOMA. In particular, we introduce a ray-tracing (RT based 5G NR network channel model and reveal that the secrecy capacity in mmWave band widely depends on the richness of radio frequency (RF environment through numerical experiments.

  15. Education for Personal Life: John MacMurray on Why Learning to Be Human Requires Emotional Discipline

    Science.gov (United States)

    MacAllister, James

    2014-01-01

    In this article I discuss the philosophy of John MacMurray, and in particular, his little-examined writings on discipline and emotion education. It is argued that discipline is a vital element in the emotion education MacMurray thought central to learning to be human, because for him it takes concerted effort to overcome the human tendency toward…

  16. Medicinal, Aromatic and Cosmetic (MAC) plants for community health and bio-cultural diversity conservation in Bali, Indonesia

    NARCIS (Netherlands)

    Leurs, Liesbeth Nathalie

    2010-01-01

    The general aim of this ethno-botanical study is to document, describe and analyse the Balinese community members’ knowledge, belief and practices with regard to medicinal, aromatic and cosmetic (MAC) plants in relation to community health and bio-cultural diversity conservation of MAC plants. This

  17. An Application of MacLaury's Vantage Theory to Abstract Categories: Identity and the Process of Categorisation

    Science.gov (United States)

    Fabiszak, Malgorzata

    2010-01-01

    This paper is an application of Robert E. MacLaury's Vantage Theory (VT) to the analysis of real life spoken discourse. It utilizes Dennis R. Preston's (1994) modification of MacLaury's VT. It elucidates how cognitive processes of coordinate selection and combination contribute to the on-line construction of category membership in the abstract…

  18. The research and application of the NDP protocol vulnerability attack and the defense technology based on SEND

    Science.gov (United States)

    Xi, Huixing

    2017-05-01

    Neighbor discovery protocol (NDP) is the underlying protocol in the IPv6 protocol, which is mainly used to solve the problem of interconnection between nodes on the same link. But with wide use of IPV6, NDP becomes the main objects of a variety of attacks due to a lack of security mechanism. The paper introduces the working principle of the NDP and methods of how the SEND protocol to enhance NDP security defense. It also analyzes and summarizes the security threats caused by the defects of the protocol itself. On the basis of the SEND protocol, the NDP data packet structure is modified to enhance the security of the SEND. An improved NDP cheating defense technology is put forward to make up the defects of the SEND protocol which can't verify the correctness of the public key and cannot bind the MAC address.

  19. DiNAMAC : A disruption tolerant, reinforcement learning-based Mac protocol for implantable body sensor networks

    NARCIS (Netherlands)

    Karuppiah Ramachandran, Vignesh Raja; Le Viet Duc, L Duc; Meratnia, Nirvana; Havinga, Paul J.M.

    Ongoing advancements in Body Sensor Networks (BSN) have enabled continuous health monitoring of chronically ill patients, with the use of implantable and body worn sensor nodes. Inevitable day-to-day activities such as walking, running, and sleeping cause severe disruptions in the wireless link

  20. On the upgrade of an optical code division PON with a code-sense ethernet MAC protocol

    NARCIS (Netherlands)

    Huiszoon, B.; Waardt, de H.; Khoe, G.D.; Koonen, A.M.J.

    2007-01-01

    We propose, for the first time, optical code-sense multiple access / collision detection to upgrade an optical code division passive optical network with minor modifications to transparently deploy Ethernet (or packet) based services.

  1. Mobile Device Management horizons for CERN Managed iOS and Mac Self-Service

    CERN Multimedia

    CERN. Geneva; MUSZKOWSKI, Maciek; BIPPUS, Vincent Nicolas

    2015-01-01

    Overview of the MDM (Mobile Device Mamagement) market in the context of the CERN needs and a discussion of technical capabilities of a range of MDM products, followed by a presentation of two new functionalities implemented using an MDM: Self-service Kiosk for Mac and delegated-management solution for professional tablets.

  2. Modeling a content-aware LTE MAC downlink scheduler with heterogeneous traffic

    DEFF Research Database (Denmark)

    Artuso, Matteo; Christiansen, Henrik Lehrmann

    2013-01-01

    The scheduling policy adopted in the LTE (Long Term Evolution) MAC layer is the most valuable degree of freedom left from the 3GPP (3rd Generation Partnership Project) consortium to the industry and the research community . This paper presents an OPNET model of the downlink scheduling in a one...

  3. Energy Efficient MAC Scheme for Wireless Sensor Networks with High-Dimensional Data Aggregate

    Directory of Open Access Journals (Sweden)

    Seokhoon Kim

    2015-01-01

    Full Text Available This paper presents a novel and sustainable medium access control (MAC scheme for wireless sensor network (WSN systems that process high-dimensional aggregated data. Based on a preamble signal and buffer threshold analysis, it maximizes the energy efficiency of the wireless sensor devices which have limited energy resources. The proposed group management MAC (GM-MAC approach not only sets the buffer threshold value of a sensor device to be reciprocal to the preamble signal but also sets a transmittable group value to each sensor device by using the preamble signal of the sink node. The primary difference between the previous and the proposed approach is that existing state-of-the-art schemes use duty cycle and sleep mode to save energy consumption of individual sensor devices, whereas the proposed scheme employs the group management MAC scheme for sensor devices to maximize the overall energy efficiency of the whole WSN systems by minimizing the energy consumption of sensor devices located near the sink node. Performance evaluations show that the proposed scheme outperforms the previous schemes in terms of active time of sensor devices, transmission delay, control overhead, and energy consumption. Therefore, the proposed scheme is suitable for sensor devices in a variety of wireless sensor networking environments with high-dimensional data aggregate.

  4. Debating Inclusion in Synecdoche, New York: A Response to Gresham and MacMillan.

    Science.gov (United States)

    Ferguson, Dianne L.; Ferguson, Philip M.

    1997-01-01

    A comprehensive review of the debate over the inclusion of children with disabilities in educational programs needs to explore research and issues beyond those considered by F. Gresham and D. MacMillan. Some of those issues are reviewed, focusing on a shift away from the medical deficit model. (SLD)

  5. The baby has not come: obstructed labour | MacKeith | South Sudan ...

    African Journals Online (AJOL)

    The baby has not come: obstructed labour. Nancy MacKeith, Wal Bichiok Wur. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's ...

  6. 76 FR 35138 - Federal Agricultural Mortgage Corporation Funding and Fiscal Affairs; Farmer Mac Risk-Based...

    Science.gov (United States)

    2011-06-16

    ... Funding and Fiscal Affairs; Farmer Mac Risk-Based Capital Stress Test, Version 5.0 AGENCY: Farm Credit... credit rating agency) in regulations addressing the Risk-Based Capital Stress Test (RBCST or stress test...) (repealing and replacing Pub. L. 110-234). B. Risk-Based Capital and Credit Ratings Under our rules, Farmer...

  7. Elevated levels of homocysteine increase IL-6 production in monocytic Mono Mac 6 cells

    NARCIS (Netherlands)

    van Aken, B. E.; Jansen, J.; van Deventer, S. J.; Reitsma, P. H.

    2000-01-01

    Hyperhomocysteinemia is a risk factor for atherosclerosis and thrombosis. The aim of this study was to analyze if exposure of monocytic cells to increased levels of homocysteine (HCY) induces the accumulation of inflammatory mediators. Interleukin (IL)-6 production by monocytic cell line Mono Mac 6

  8. Knowledge, Power, and Social Policy: John M. MacEachran and Alberta's 1928 Sexual Sterilization Act

    Science.gov (United States)

    Puplampu, Korbla P.

    2008-01-01

    This article examines how academic knowledge and power have shaped the discourse on human classification and how political authorities use academic knowledge producers to legitimize public policy. Specifically, the article draws on the role of John M. MacEachran, a former academic at the University of Alberta, in the implementation of the Alberta…

  9. 78 FR 65541 - Federal Agricultural Mortgage Corporation Funding and Fiscal Affairs; Farmer Mac Liquidity...

    Science.gov (United States)

    2013-11-01

    ... attention issues and concerns that they believe warrant further or heightened FCA scrutiny. The second...; Divide the 90-day liquidity reserve into three tiers so Farmer Mac has a sufficient amount of cash and... that can be traded at fair value and an explicit public backstop.'' From the FCA's perspective, whether...

  10. Muusikamaailm : James Levine 25 aastat Metis. Taveneri ja MacMillani millenniumiteosed. Avafestival Sydneys / Priit Kuusk

    Index Scriptorium Estoniae

    Kuusk, Priit, 1938-

    2000-01-01

    J. Harbisoni ooperi "The Great Gatsby" esmalavastusega tähistab New Yorgi Metropolitan Opera oma 25-aastast koostööd J. Levine'iga. J. Taveneri uudisteosest "The Fall and Resurrection", J. MacMillani millenniumiteose "Magnificat" maailmaesiettekandest. 5.-26. jaan. toimuvast Sydney muusikafestivalist

  11. Endotoxin testing of proteins for parenteral administration using the Mono Mac 6 assay

    DEFF Research Database (Denmark)

    Moesby, Lise; Hansen, E W; Christensen, J D

    2000-01-01

    Pharmaceutical products containing proteins cause problems in testing for endotoxin and pyrogens. Many proteins interfere with the LAL test and the proteins are immunogenic in rabbits. The monocytic cell line Mono Mac 6 is an alternative assay for detection of endotoxin and other pyrogens....

  12. Not the Sum of Its Parts: A Critical Review of the MacDonald Triad.

    Science.gov (United States)

    Parfitt, Charlotte Hannah; Alleyne, Emma

    2018-01-01

    The MacDonald triad posits that animal cruelty, fire setting, and bed wetting in childhood is indicative of later aggressive and violent behavior in adults. Researchers refer to this phenomenon as a precursor to later antisocial behaviors including serial and sexual murder; while practitioners cite the triad in clinical formulations and risk assessments. However, there is yet to be a critical review and consolidation of the literature that establishes whether there is empirical support. This article explores the validity of the triad. We conducted a narrative review of the relevant studies examining the MacDonald triad and its individual constituents. There is evidence that any one of the triad behaviors could predict future violent offending, but it is very rare to find all three behaviors together as predictors. Thus, the empirical research on the MacDonald triad does not fully substantiate its premise. Rather, it would appear that the triad, or its individual constituents, is better used as an indicator of dysfunctional home environments, or poor coping skills in children. Future research is needed with robust and rigorous methodologies (e.g., adequate control groups, longitudinal designs) to fully establish the MacDonald triad's validity. Finally, further consideration is needed as to whether the triad behaviors are more indicative of other problematic outcomes (e.g., maladaptive coping to life stressors).

  13. The Big Mac and Teaching about Japan. Footnotes. Volume 8, Number 5

    Science.gov (United States)

    Ellington, Lucien

    2003-01-01

    The Big Mac can be effective tool in helping students achieve a better understanding of Japan. It can defeat Orientalist stereotypes about the Japanese--and also challenge young people who might have oversimplified notions of what exactly occurs when U.S. fast food chains take root in another culture. Many deride McDonald's as a villain…

  14. Detecting DIF in Polytomous Items Using MACS, IRT and Ordinal Logistic Regression

    Science.gov (United States)

    Elosua, Paula; Wells, Craig

    2013-01-01

    The purpose of the present study was to compare the Type I error rate and power of two model-based procedures, the mean and covariance structure model (MACS) and the item response theory (IRT), and an observed-score based procedure, ordinal logistic regression, for detecting differential item functioning (DIF) in polytomous items. A simulation…

  15. Ultrasonication of pyrogenic microorganisms improves the detection of pyrogens in the Mono Mac 6 assay

    DEFF Research Database (Denmark)

    Moesby, Lise; Hansen, E W; Christensen, J D

    2000-01-01

    The monocytic cell line Mono Mac 6 is sensitive to pyrogens. When exposed to pyrogens secretion of interleukin-6 is induced. However, some eukaryotic pyrogenic microorganisms are not detectable. The aim of this study is to introduce a pretreatment of samples to expand the detection range of the a...

  16. Dependence of AeroMACS Interference on Airport Radiation Pattern Characteristics

    Science.gov (United States)

    Wilson, Jeffrey D.

    2012-01-01

    AeroMACS (Aeronautical Mobile Airport Communications System), which is based upon the IEEE 802.16e mobile wireless standard, is expected to be implemented in the 5091 to 5150 MHz frequency band. As this band is also occupied by Mobile Satellite Service (MSS) feeder uplinks, AeroMACS must be designed to avoid interference with this incumbent service. The aspects of AeroMACS operation that present potential interference are under analysis in order to enable the definition of standards that assure that such interference will be avoided. In this study, the cumulative interference power distribution at low earth orbit from AeroMACS transmitters at the 497 major airports in the contiguous United States was simulated with the Visualyse Professional software. The dependence of the interference power on the number of antenna beams per airport, gain patterns, and beam direction orientations was simulated. As a function of these parameters, the simulation results are presented in terms of the limitations on transmitter power required to maintain the cumulative interference power under the established threshold.

  17. 78 FR 65145 - Federal Agricultural Mortgage Corporation Funding and Fiscal Affairs; Farmer Mac Capital Planning

    Science.gov (United States)

    2013-10-31

    ... capital adequacy and capital planning. \\4\\ Bank for International Settlements, Basel Committee on Banking....60--Corporate Business Planning The Farm Credit Council commented that our reference to ``goals and.... 652.60 to read as follows: Sec. 652.60 Corporate business planning. (a) Farmer Mac's board of...

  18. Nuclear power history calculation for subcritical systems using Euler-MacLaurin formula

    International Nuclear Information System (INIS)

    Henrice Junior, Edson; Goncalves, Alessandro da Cruz

    2013-01-01

    This paper presents an efficient method for calculating the reactivity using inverse point kinetic equation for subcritical systems by applying the Euler-MacLaurin summation formula to calculate the nuclear power history. In accordance with the accuracy of the numerical results, this method does not require a large number of points for calculation, providing accurate results with low computational cost. (author)

  19. Scalable Video Streaming Adaptive to Time-Varying IEEE 802.11 MAC Parameters

    Science.gov (United States)

    Lee, Kyung-Jun; Suh, Doug-Young; Park, Gwang-Hoon; Huh, Jae-Doo

    This letter proposes a QoS control method for video streaming service over wireless networks. Based on statistical analysis, the time-varying MAC parameters highly related to channel condition are selected to predict available bitrate. Adaptive bitrate control of scalably-encoded video guarantees continuity in streaming service even if the channel condition changes abruptly.

  20. Tuning in to pavement radio

    NARCIS (Netherlands)

    Ellis, S.

    1989-01-01

    This article describes a phenomenon known all over Africa, for which there is no really satisfactory term in English but which is summed up in the French term 'radio trottoir', literally 'pavement radio'. It may be defined as the popular and unofficial discussion of current affairs in Africa,