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Sample records for network switch prototype

  1. Neuromorphic atomic switch networks.

    Directory of Open Access Journals (Sweden)

    Audrius V Avizienis

    Full Text Available Efforts to emulate the formidable information processing capabilities of the brain through neuromorphic engineering have been bolstered by recent progress in the fabrication of nonlinear, nanoscale circuit elements that exhibit synapse-like operational characteristics. However, conventional fabrication techniques are unable to efficiently generate structures with the highly complex interconnectivity found in biological neuronal networks. Here we demonstrate the physical realization of a self-assembled neuromorphic device which implements basic concepts of systems neuroscience through a hardware-based platform comprised of over a billion interconnected atomic-switch inorganic synapses embedded in a complex network of silver nanowires. Observations of network activation and passive harmonic generation demonstrate a collective response to input stimulus in agreement with recent theoretical predictions. Further, emergent behaviors unique to the complex network of atomic switches and akin to brain function are observed, namely spatially distributed memory, recurrent dynamics and the activation of feedforward subnetworks. These devices display the functional characteristics required for implementing unconventional, biologically and neurally inspired computational methodologies in a synthetic experimental system.

  2. Optical packet switched networks

    DEFF Research Database (Denmark)

    Hansen, Peter Bukhave

    1999-01-01

    range that covers the EDFA window and conversion speeds of 20 Gbit/s and 40 Gbit/s are presented. Furthermore, the regenerative capability due to a nonlinear transfer function is verified at 20 Gbit/s. Following, the transmission characteristics of the IWC is analysed. The chirp measurements indicate...... in interferometric wavelength converters is investigated showing that a 10 Gbit/s 19 4x4 swich blocks can be cascaded at a BER of 10-14. An analytical traffic model enables the calculation of the traffice performance of a WDM packet network. Hereby the importance of WDM and wavelegth conversion in the switch blocks...... that there is a difference in the transmission properties for co- and counter propagation conversion, which is supported by transmission experiments. The combined use of SOA gates and interferometric wavelength converters illustrates the regenerative capability of the IWCs at 2.5, 10 and 20 Gbit/s by increasing the input...

  3. Principles of broadband switching and networking

    CERN Document Server

    Liew, Soung C

    2010-01-01

    An authoritative introduction to the roles of switching and transmission in broadband integrated services networks Principles of Broadband Switching and Networking explains the design and analysis of switch architectures suitable for broadband integrated services networks, emphasizing packet-switched interconnection networks with distributed routing algorithms. The text examines the mathematical properties of these networks, rather than specific implementation technologies. Although the pedagogical explanations in this book are in the context of switches, many of the fundamenta

  4. Circuit switched optical networks

    DEFF Research Database (Denmark)

    Kloch, Allan

    2003-01-01

    -connects can substitute the electrical nodes that today connect the installed optical fibres. This substitution will enable a massive increase in capacity since the bandwidth of the individual wavelength channels can be increased drastically when the electronic bit processing can be omitted. Furthermore......, it is expected that the optical solution will offer an economical benefit for hight bit rate networks. This thesis begins with a discussion of the expected impact on communications systems from the rapidly growing IP traffic, which is expected to become the dominant source for traffic. IP traffic has some...... characteristics, which are best supported by an optical network. The interest for such an optical network is exemplified by the formation of the ACTS OPEN project which aim was to investigate the feasibility of an optical network covering Europe. Part of the work presented in this thesis is carried out within...

  5. Prototype-Incorporated Emotional Neural Network.

    Science.gov (United States)

    Oyedotun, Oyebade K; Khashman, Adnan

    2017-08-15

    Artificial neural networks (ANNs) aim to simulate the biological neural activities. Interestingly, many ''engineering'' prospects in ANN have relied on motivations from cognition and psychology studies. So far, two important learning theories that have been subject of active research are the prototype and adaptive learning theories. The learning rules employed for ANNs can be related to adaptive learning theory, where several examples of the different classes in a task are supplied to the network for adjusting internal parameters. Conversely, the prototype-learning theory uses prototypes (representative examples); usually, one prototype per class of the different classes contained in the task. These prototypes are supplied for systematic matching with new examples so that class association can be achieved. In this paper, we propose and implement a novel neural network algorithm based on modifying the emotional neural network (EmNN) model to unify the prototype- and adaptive-learning theories. We refer to our new model as ``prototype-incorporated EmNN''. Furthermore, we apply the proposed model to two real-life challenging tasks, namely, static hand-gesture recognition and face recognition, and compare the result to those obtained using the popular back-propagation neural network (BPNN), emotional BPNN (EmNN), deep networks, an exemplar classification model, and k-nearest neighbor.

  6. Switch-connected HyperX network

    Science.gov (United States)

    Chen, Dong; Heidelberger, Philip

    2018-02-13

    A network system includes a plurality of sub-network planes and global switches. The sub-network planes have a same network topology as each other. Each of the sub-network planes includes edge switches. Each of the edge switches has N ports. Each of the global switches is configured to connect a group of edge switches at a same location in the sub-network planes. In each of the sub-network planes, some of the N ports of each of the edge switches are connected to end nodes, and others of the N ports are connected to other edge switches in the same sub-network plane, other of the N ports are connected to at least one of the global switches.

  7. Pinning Synchronization of Switched Complex Dynamical Networks

    Directory of Open Access Journals (Sweden)

    Liming Du

    2015-01-01

    Full Text Available Network topology and node dynamics play a key role in forming synchronization of complex networks. Unfortunately there is no effective synchronization criterion for pinning synchronization of complex dynamical networks with switching topology. In this paper, pinning synchronization of complex dynamical networks with switching topology is studied. Two basic problems are considered: one is pinning synchronization of switched complex networks under arbitrary switching; the other is pinning synchronization of switched complex networks by design of switching when synchronization cannot achieved by using any individual connection topology alone. For the two problems, common Lyapunov function method and single Lyapunov function method are used respectively, some global synchronization criteria are proposed and the designed switching law is given. Finally, simulation results verify the validity of the results.

  8. Design of all Optical Packet Switching Networks

    Directory of Open Access Journals (Sweden)

    Hussein T. Mouftah

    2002-06-01

    Full Text Available Optical switches and wavelength converters are recognized as two of the most important DWDM system components in future all-optical networks. Optical switches perform the key functions of flexible routing, reconfigurable optical cross-connect (OXC, network protection and restoration, etc. in optical networks. Wavelength Converters are used to shift one incoming wavelength to another outgoing wavelength when this needs to be done.  Always residing in optical switches, they can effectively alleviate the blocking probability and help solve contention happening at the output port of switches. The deployment of wavelength converters within optical switches provides robust routing, switching and network management in optical layer, which is critical to the emerging all-optical Internet. However, the high cost of wavelength converters at current stage of manufacturing technology has to be taken into consideration when we design node architectures for an optical network. Our research explores the efficiency of wavelength converters in a long-haul optical network at different degrees of traffic load by running a simulation. Then, we propose a new cost-effective way to optimally design wavelength-convertible switch so as to achieve higher network performance while still keeping the total network cost down. Meanwhile, the routing and wavelength assignment (RWA algorithm used in the research is designed to be a generic one for both large-scale and small-scale traffic. Removing the constraint on the traffic load makes the RWA more adaptive and robust. When this new RWA works in conjunction with a newly introduced concept of wavelength-convertible switches, we shall explore the impact of large-scale traffic on the role of wavelength converter so as to determine the method towards optimal use of wavelength convertible switches for all-optical networks.

  9. Hybrid Optical Switching for Data Center Networks

    Directory of Open Access Journals (Sweden)

    Matteo Fiorani

    2014-01-01

    Full Text Available Current data centers networks rely on electronic switching and point-to-point interconnects. When considering future data center requirements, these solutions will raise issues in terms of flexibility, scalability, performance, and energy consumption. For this reason several optical switched interconnects, which make use of optical switches and wavelength division multiplexing (WDM, have been recently proposed. However, the solutions proposed so far suffer from low flexibility and are not able to provide service differentiation. In this paper we introduce a novel data center network based on hybrid optical switching (HOS. HOS combines optical circuit, burst, and packet switching on the same network. In this way different data center applications can be mapped to the optical transport mechanism that best suits their traffic characteristics. Furthermore, the proposed HOS network achieves high transmission efficiency and reduced energy consumption by using two parallel optical switches. We consider the architectures of both a traditional data center network and the proposed HOS network and present a combined analytical and simulation approach for their performance and energy consumption evaluation. We demonstrate that the proposed HOS data center network achieves high performance and flexibility while considerably reducing the energy consumption of current solutions.

  10. Feature to prototype transition in neural networks

    Science.gov (United States)

    Krotov, Dmitry; Hopfield, John

    Models of associative memory with higher order (higher than quadratic) interactions, and their relationship to neural networks used in deep learning are discussed. Associative memory is conventionally described by recurrent neural networks with dynamical convergence to stable points. Deep learning typically uses feedforward neural nets without dynamics. However, a simple duality relates these two different views when applied to problems of pattern classification. From the perspective of associative memory such models deserve attention because they make it possible to store a much larger number of memories, compared to the quadratic case. In the dual description, these models correspond to feedforward neural networks with one hidden layer and unusual activation functions transmitting the activities of the visible neurons to the hidden layer. These activation functions are rectified polynomials of a higher degree rather than the rectified linear functions used in deep learning. The network learns representations of the data in terms of features for rectified linear functions, but as the power in the activation function is increased there is a gradual shift to a prototype-based representation, the two extreme regimes of pattern recognition known in cognitive psychology. Simons Center for Systems Biology.

  11. Investment in electricity networks with transmission switching

    DEFF Research Database (Denmark)

    Villumsen, Jonas Christoffer; Philpott, A.B.

    2012-01-01

    allows the solution of large problem instances. The methodology is illustrated by its application to a problem of determining the optimal investment in switching equipment and transmission capacity for an existing network. Computational tests on IEEE test networks with 73 nodes and 118 nodes confirm...

  12. Development of a prototype T-shaped fast switching device for electron cyclotron current drive systems

    Science.gov (United States)

    Sekiguchi, Kenji; Nagashima, Koji; Honzu, Toshihiko; Saigusa, Mikio; Oda, Yasuhisa; Takahashi, Koji; Sakamoto, Keishi

    2016-09-01

    A T-shaped high-power switching device composed of circular corrugated waveguides with three ports and double dielectric disks made of sapphire was proposed as a fast switching device based on a new principle in electron cyclotron current drive systems. This switching device has the advantages of operating at a fixed frequency and being compact. The design of the prototype switch was obtained by numerical simulations using a finite-difference time-domain (FDTD) method. The size of these components was optimized for the frequency band of 170 GHz. Low-power tests were carried out in a cross-shaped model.

  13. Optical Multidimensional Switching for Data Center Networks

    DEFF Research Database (Denmark)

    Kamchevska, Valerija

    2017-01-01

    : the first one referring to hardware-software integration where the data plane is integrated with a centralized control plane deploying a software defined controller, and the second one referring to on-chip integration of devices in the data plane ultimately leading to integrated systems and networks on chip....... Software controlled switching using an on-chip integrated fiber switch is demonstrated and enabling of additional network functionalities such as multicast and optical grooming is experimentally confirmed. Altogether this work demonstrates the potential of optical switching technologies...... avoiding power hungry optical-electrical-optical conversions at each node. This Ph.D. thesis focuses precisely on the application of optical technologies in data center networks where optics is not only used for extending the reach, but more importantly the benefits of photonic devices are exploited...

  14. A Lossless Switch for Data Acquisition Networks

    CERN Document Server

    Jereczek, Grzegorz Edmund; for the ATLAS collaboration

    2015-01-01

    The recent trends in software-defined networking (SDN) and network function virtualization (NFV) are boosting the advance of software-based packet processing and forwarding on commodity servers. Although performance has traditionally been the challenge of this approach, this situation changes with modern server platforms. High performance load balancers, proxies, virtual switches and other network functions can be now implemented in software and not limited to specialized commercial hardware, thus reducing cost and increasing the flexibility. In this paper we design a lossless software-based switch for high bandwidth data acquisition (DAQ) networks, using the ATLAS experiment at CERN as a case study. We prove that it can effectively solve the incast pathology arising from the many-to-one communication pattern present in DAQ networks by providing extremely high buffering capabilities. We evaluate this on a commodity server equipped with twelve 10 Gbps Ethernet interfaces providing a total bandwidth of 120 Gbps...

  15. Software Defined Networking (SDN) controlled all optical switching networks with multi-dimensional switching architecture

    Science.gov (United States)

    Zhao, Yongli; Ji, Yuefeng; Zhang, Jie; Li, Hui; Xiong, Qianjin; Qiu, Shaofeng

    2014-08-01

    Ultrahigh throughout capacity requirement is challenging the current optical switching nodes with the fast development of data center networks. Pbit/s level all optical switching networks need to be deployed soon, which will cause the high complexity of node architecture. How to control the future network and node equipment together will become a new problem. An enhanced Software Defined Networking (eSDN) control architecture is proposed in the paper, which consists of Provider NOX (P-NOX) and Node NOX (N-NOX). With the cooperation of P-NOX and N-NOX, the flexible control of the entire network can be achieved. All optical switching network testbed has been experimentally demonstrated with efficient control of enhanced Software Defined Networking (eSDN). Pbit/s level all optical switching nodes in the testbed are implemented based on multi-dimensional switching architecture, i.e. multi-level and multi-planar. Due to the space and cost limitation, each optical switching node is only equipped with four input line boxes and four output line boxes respectively. Experimental results are given to verify the performance of our proposed control and switching architecture.

  16. Lagrangian modeling of switching electrical networks

    NARCIS (Netherlands)

    Scherpen, Jacquelien M.A.; Jeltsema, Dimitri; Klaassens, J. Ben

    2003-01-01

    In this paper, a general and systematic method is presented to model topologically complete electrical networks, with or without multiple or single switches, within the Euler–Lagrange framework. Apart from the physical insight that can be obtained in this way, the framework has proven to be useful

  17. Versatile emulator for automatically switched optical networks

    Science.gov (United States)

    Stilling, Bernd; Nathansen, Martin

    2001-10-01

    Development, testing and deployment of routing and signaling protocols for automatically switched optical networks (ASON) are considerably simplified by using an emulation tool. In this paper we present an emulator that supports OSPF routing and (G)MPLS based signaling. Currently the emulator supports the signaling protocol CR-LDP but we are working on the integration of RSVP-TE. Running complete protocol stacks for each emulated node enables the emulator to fill the gap between a network simulation and a real network. To allow the emulation of very large networks which can not be done on a single workstation the network can be emulated using a set of workstation. By adding additional workstations the number of emulated nodes is almost unlimited. The architecture and the functionality of the emulator are described and an example of an emulation is given. The example network with 16 nodes is investigated regarding the behavior in case of network failures.

  18. 4x4 optical packet switching of asynchronous burst optical packets with a prototype, 4x4 label processing and switching sub-system.

    Science.gov (United States)

    Urata, Ryohei; Nakahara, Tatsushi; Takenouchi, Hirokazu; Segawa, Toru; Ishikawa, Hiroshi; Ohki, Akira; Sugiyama, Hiroki; Nishihara, Susumu; Takahashi, Ryo

    2010-07-19

    We report a prototype, 4x4 (4 input/4 output) label processing and switching sub-system for 10-Gb/s asynchronous burst variable-length optical packets. With the prototype, we perform a 4x4 optical packet switching demonstration, achieving error-free (BERswitching operation for all possible input/output combinations (16 switching paths) simultaneously. Power consumption and latency of the entire, self-contained sub-system is 83 W (includes fan power) and 300 ns, respectively.

  19. Intelligent Network Flow Optimization (INFLO) prototype acceptance test summary.

    Science.gov (United States)

    2015-05-01

    This report summarizes the results of System Acceptance Testing for the implementation of the Intelligent Network : Flow Optimization (INFLO) Prototype bundle within the Dynamic Mobility Applications (DMA) portion of the Connected : Vehicle Program. ...

  20. Design and Prototype of an Automated Column-Switching HPLC System for Radiometabolite Analysis

    Directory of Open Access Journals (Sweden)

    Neil Vasdev

    2016-08-01

    Full Text Available Column-switching high performance liquid chromatography (HPLC is extensively used for the critical analysis of radiolabeled ligands and their metabolites in plasma. However, the lack of streamlined apparatus and consequently varying protocols remain as a challenge among positron emission tomography laboratories. We report here the prototype apparatus and implementation of a fully automated and simplified column-switching procedure to allow for the easy and automated determination of radioligands and their metabolites in up to 5 mL of plasma. The system has been used with conventional UV and coincidence radiation detectors, as well as with a single quadrupole mass spectrometer.

  1. Design and Prototype of an Automated Column-Switching HPLC System for Radiometabolite Analysis.

    Science.gov (United States)

    Vasdev, Neil; Collier, Thomas Lee

    2016-08-17

    Column-switching high performance liquid chromatography (HPLC) is extensively used for the critical analysis of radiolabeled ligands and their metabolites in plasma. However, the lack of streamlined apparatus and consequently varying protocols remain as a challenge among positron emission tomography laboratories. We report here the prototype apparatus and implementation of a fully automated and simplified column-switching procedure to allow for the easy and automated determination of radioligands and their metabolites in up to 5 mL of plasma. The system has been used with conventional UV and coincidence radiation detectors, as well as with a single quadrupole mass spectrometer.

  2. Fast packet switch architectures for broadband integrated services digital networks

    Science.gov (United States)

    Tobagi, Fouad A.

    1990-01-01

    Background information on networking and switching is provided, and the various architectures that have been considered for fast packet switches are described. The focus is solely on switches designed to be implemented electronically. A set of definitions and a brief description of the functionality required of fast packet switches are given. Three basic types of packet switches are identified: the shared-memory, shared-medium, and space-division types. Each of these is described, and examples are given.

  3. Measurement of switching latency in high data rate Ethernet networks

    OpenAIRE

    Hegr, Tomáš; Vozňák, Miroslav; Kozák, Miloš; Boháč, Leoš

    2015-01-01

    The paper deals with a methodology of switching latency measurement in switched Ethernet networks. The switching latency is parameter necessary for simulation and design of low-latency networks that are often intended for realtime control inherent to many industrial applications. The proposed measurement methodology provides a simple way of switching the latency determination and vendor quoted latency values verification directly at the physical layer. Numerous experimental measurements...

  4. Quality of service in optical packet switched networks

    CERN Document Server

    Rahbar, Akbar G

    2015-01-01

    This book is a comprehensive study on OPS networks, its architectures, and developed techniques for improving its quality of switching and managing quality of service.  The book includes: Introduction to OPS networks, OOFDM networks, GMPLS-enabled optical networks, QoS in OPS networks Hybrid contention avoidance/resolution schemes in both long-haul and metro optical networks Hybrid optical switching schemes

  5. A Mobile Application Prototype using Network Coding

    DEFF Research Database (Denmark)

    Pedersen, Morten Videbæk; Heide, Janus; Fitzek, Frank

    2010-01-01

    This paper looks into implementation details of network coding for a mobile application running on commercial mobile phones. We describe the necessary coding operations and algorithms that implements them. The coding algorithms forms the basis for a implementation in C++ and Symbian C++. We report...... on practical measurement results of coding throughput and energy consumption for a single-source multiple-sinks network, with and without recoding at the sinks. These results confirm that network coding is practical even on computationally weak platforms, and that network coding potentially can be used...

  6. Simulation of mixed switched-capacitor/digital networks with signal-driven switches

    Science.gov (United States)

    Suyama, Ken; Tsividis, Yannis P.; Fang, San-Chin

    1990-12-01

    The simulation of mixed switched-capacitor/digital (SC/D) networks containing capacitors, independent and linear-dependent voltage sources, switches controlled either by periodic or nonperiodic Boolean signals, latched comparators, and logic gates is considered. A unified linear switched-capacitor network (SCN) and mixed SC/D network simulator, SWITCAP2, and its applications to several widely used and novel nonlinear SCNs are discussed. The switches may be controlled by periodic waveforms and by nonperiodic waveforms from the outputs of comparators and logic gates. The signal-dependent modification of network topology through the comparators, logic gates, and signal-driven switches makes the modeling of various nonlinear switched-capacitor circuits possible. Simulation results for a pulse-code modulation (PCM) voice encoder, a sigma-delta modulator, a neural network, and a phase-locked loop (PLL) are presented to demonstrate the flexibility of the approach.

  7. An evaluation of Access Tier local area network switches.

    Energy Technology Data Exchange (ETDEWEB)

    Eldridge, John M.; Olsberg, Ronald R.

    2004-06-01

    This reports tabulates the Test and Evaluation results of the Access Class Switch tests conducted by members of Department 9336. About 15 switches were reviewed for use in the enterprise network as access tier switches as defined in a three tier architecture. The Access Switch Tier has several functions including: aggregate customer desktop ports, preserve and apply QoS tags, provide switched LAN access, provide VLAN assignment, as well as others. The typical switch size is 48 or less user ports. The evaluation team reviewed network switch evaluation reports from the Tolly Group as well as other sources. We then used these reports as a starting point to identify particular switches for evaluation. In general we reviewed the products of dominant equipment manufacturers. Also, based on architectural design requirements, the majority of the switches tested were of relatively small monolithic unit variety.

  8. The network management expert system prototype for Sun Workstations

    Science.gov (United States)

    Leigh, Albert

    1990-01-01

    Networking has become one of the fastest growing areas in the computer industry. The emergence of distributed workstations make networking more popular because they need to have connectivity between themselves as well as with other computer systems to share information and system resources. Making the networks more efficient and expandable by selecting network services and devices that fit to one's need is vital to achieve reliability and fast throughput. Networks are dynamically changing and growing at a rate that outpaces the available human resources. Therefore, there is a need to multiply the expertise rapidly rather than employing more network managers. In addition, setting up and maintaining networks by following the manuals can be tedious and cumbersome even for an experienced network manager. This prototype expert system was developed to experiment on Sun Workstations to assist system and network managers in selecting and configurating network services.

  9. An interaction switch predicts the nested architecture of mutualistic networks.

    Science.gov (United States)

    Zhang, Feng; Hui, Cang; Terblanche, John S

    2011-08-01

    Nested architecture is distinctive in plant-animal mutualistic networks. However, to date an integrative and quantitative explanation has been lacking. It is evident that species often switch their interactive partners in real-world mutualistic networks such as pollination and seed-dispersal networks. By incorporating an interaction switch into a novel multi-population model, we show that the nested architecture rapidly emerges from an initially random network. The model allowing interaction switches between partner species produced predictions which fit remarkably well with observations from 81 empirical networks. Thus, the nested architecture in mutualistic networks could be an intrinsic physical structure of dynamic networks and the interaction switch is likely a key ecological process that results in nestedness of real-world networks. Identifying the biological processes responsible for network structures is thus crucial for understanding the architecture of ecological networks. © 2011 Blackwell Publishing Ltd/CNRS.

  10. Finite-time synchronization of uncertain coupled switched neural networks under asynchronous switching.

    Science.gov (United States)

    Wu, Yuanyuan; Cao, Jinde; Li, Qingbo; Alsaedi, Ahmed; Alsaadi, Fuad E

    2017-01-01

    This paper deals with the finite-time synchronization problem for a class of uncertain coupled switched neural networks under asynchronous switching. By constructing appropriate Lyapunov-like functionals and using the average dwell time technique, some sufficient criteria are derived to guarantee the finite-time synchronization of considered uncertain coupled switched neural networks. Meanwhile, the asynchronous switching feedback controller is designed to finite-time synchronize the concerned networks. Finally, two numerical examples are introduced to show the validity of the main results. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Analyses of resource reservation schemes for optical burst switching networks

    Science.gov (United States)

    Solanska, Michaela; Scholtz, Lubomir; Ladanyi, Libor; Mullerova, Jarmila

    2017-12-01

    With growing demands of Internet Protocol services for transmission capacity and speed, the Optical Burst Switching presents the solution for future high-speed optical networks. Optical Burst Switching is a technology for transmitting large amounts of data bursts through a transparent optical switching network. To successfully transmit bursts over OBS network and reach the destination node, resource reservation schemes have to be implemented to allocate resources and configure optical switches for that burst at each node. The one-way resource reservation schemes and the performance evaluation of reservation schemes are presented. The OBS network model is performed using OMNeT++ simulation environment. During the reservation of network resources, the optical cross-connect based on semiconductor optical amplifier is used as the core node. Optical switches based on semiconductor optical amplifiers are a promising technology for high-speed optical communication networks.

  12. Coactivation of Cognitive Control Networks During Task Switching.

    Science.gov (United States)

    Yin, Shouhang; Deák, Gedeon; Chen, Antao

    2017-12-14

    The ability to flexibly switch between tasks is considered an important component of cognitive control that involves frontal and parietal cortical areas. The present study was designed to characterize network dynamics across multiple brain regions during task switching. Functional magnetic resonance images (fMRI) were captured during a standard rule-switching task to identify switching-related brain regions. Multiregional psychophysiological interaction (PPI) analysis was used to examine effective connectivity between these regions. During switching trials, behavioral performance declined and activation of a generic cognitive control network increased. Concurrently, task-related connectivity increased within and between cingulo-opercular and fronto-parietal cognitive control networks. Notably, the left inferior frontal junction (IFJ) was most consistently coactivated with the 2 cognitive control networks. Furthermore, switching-dependent effective connectivity was negatively correlated with behavioral switch costs. The strength of effective connectivity between left IFJ and other regions in the networks predicted individual differences in switch costs. Task switching was supported by coactivated connections within cognitive control networks, with left IFJ potentially acting as a key hub between the fronto-parietal and cingulo-opercular networks. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  13. OPTICAL BURST SWITCHING PROTOCOLS IN ALL-OPTICAL NETWORKS

    OpenAIRE

    KIRCI, Pınar; ZAİM, A.Halim

    2012-01-01

    In this paper, all optical network's  general structure  is briefly described  and all optical network's optical switching methods is concantrated on. All  optical network's  classification is presented according to switching methods  and burst switching methods studied carefully.The protocols which are defined for burst switching are studied. One of these protocols JET (Just-Enough-Time) which is mostly studied, is introduced. And the other protocol JIT (Just-In-Time) is prese...

  14. Deterministic bound for avionics switched networks according to networking features using network calculus

    Directory of Open Access Journals (Sweden)

    Feng HE

    2017-12-01

    Full Text Available The state of the art avionics system adopts switched networks for airborne communications. A major concern in the design of the networks is the end-to-end guarantee ability. Analytic methods have been developed to compute the worst-case delays according to the detailed configurations of flows and networks within avionics context, such as network calculus and trajectory approach. It still lacks a relevant method to make a rapid performance estimation according to some typically switched networking features, such as networking scale, bandwidth utilization and average flow rate. The goal of this paper is to establish a deterministic upper bound analysis method by using these networking features instead of the complete network configurations. Two deterministic upper bounds are proposed from network calculus perspective: one is for a basic estimation, and another just shows the benefits from grouping strategy. Besides, a mathematic expression for grouping ability is established based on the concept of network connecting degree, which illustrates the possibly minimal grouping benefit. For a fully connected network with 4 switches and 12 end systems, the grouping ability coming from grouping strategy is 15–20%, which just coincides with the statistical data (18–22% from the actual grouping advantage. Compared with the complete network calculus analysis method for individual flows, the effectiveness of the two deterministic upper bounds is no less than 38% even with remarkably varied packet lengths. Finally, the paper illustrates the design process for an industrial Avionics Full DupleX switched Ethernet (AFDX networking case according to the two deterministic upper bounds and shows that a better control for network connecting, when designing a switched network, can improve the worst-case delays dramatically. Keywords: Deterministic bound, Grouping ability, Network calculus, Networking features, Switched networks

  15. Techniques for labeling of optical signals in bust switched networks

    DEFF Research Database (Denmark)

    Tafur Monroy, Idelfonso; Koonen, A. M. J.; Zhang, Jianfeng

    2003-01-01

    We present a review of significant issues related to labeled optical burst switched (LOBS) networks and technologies enabling future optical internet networks. Labeled optical burst switching provides a quick and efficient forwarding mechanism of IP packets/bursts over wavelength division...... multiplexed (WDM) networks due to its single forwarding algorithm, thus yielding low latency, and it enables scaling to terabit rates. Moreover, LOBS is compatible with the general multiprotocol label switching (GMPLS) framework for a unified control plane. We present a review on techniques for labeling...... of optical signals for LOBS networks, including experimental results, we discuss as well issues for further research....

  16. An Enhanced Global Precipitation Measurement (GPM) Validation Network Prototype

    Science.gov (United States)

    Schwaller, Matthew R.; Morris, K. Robert

    2009-01-01

    A Validation Network (VN) prototype is currently underway that compares data from the Precipitation Radar (PR) instrument on NASA's Tropical Rainfall Measuring Mission (TRMM) satellite to similar measurements from the U.S. national network of operational weather radars. This prototype is being conducted as part of the ground validation activities of NASA's Global Precipitation Measurement (GPM) mission. GPM will carry a Dual-frequency Precipitation Radar instrument (DPR) with similar characteristics to the TRMM PR. The purpose of the VN is to identify and resolve significant discrepancies between the U.S. national network of ground radar (GR) observations and satellite observations. The ultimate goal of such comparisons is to understand and resolve the first order variability and bias of precipitation retrievals in different meteorological/hydrological regimes at large scales. This paper presents a description of, and results from, an improved algorithm for volume matching and comparison of PR and ground radar observations.

  17. Rapid prototyping of microfluidic switches in poly(dimethyl siloxane) and their actuation by electro-osmotic flow

    Science.gov (United States)

    Duffy, David C.; Schueller, Olivier J. A.; Brittain, Scott T.; Whitesides, George M.

    1999-09-01

    This paper describes a procedure for rapidly and conveniently prototyping microfluidic devices that are useful with aqueous solutions. A design (with diameters of channels icons/Journals/Common/ge" ALT="ge" ALIGN="TOP"/>20 µm) is created in a computer-aided design program and printed at high resolution on a transparency. This transparency is used as a mask in photolithography to create a master in positive relief photoresist: casting poly(dimethyl siloxane) (PDMS) against this master yields a polymeric replica containing a network of bas-relief channels. The channels are closed and sealed irreversibly by oxidizing the replica and another flat substrate (PDMS, glass, silicon, silicon oxide) in an oxygen plasma and bringing the two surfaces into conformal contact. Oxidation of the polymer allows the formation of a seal without using adhesives; it also generates channels that support electro-osmotic flow (EOF) and fill easily with aqueous solutions. Two microfluidic devices - a fluidic switch and a side channel flow controller - have been fabricated using this rapid prototyping methodology. These devices were tested using aqueous solutions as the test fluid and actuated by EOF.

  18. Neural networks supporting switching, hypothesis testing, and rule application.

    Science.gov (United States)

    Liu, Zhiya; Braunlich, Kurt; Wehe, Hillary S; Seger, Carol A

    2015-10-01

    We identified dynamic changes in recruitment of neural connectivity networks across three phases of a flexible rule learning and set-shifting task similar to the Wisconsin Card Sort Task: switching, rule learning via hypothesis testing, and rule application. During fMRI scanning, subjects viewed pairs of stimuli that differed across four dimensions (letter, color, size, screen location), chose one stimulus, and received feedback. Subjects were informed that the correct choice was determined by a simple unidimensional rule, for example "choose the blue letter". Once each rule had been learned and correctly applied for 4-7 trials, subjects were cued via either negative feedback or visual cues to switch to learning a new rule. Task performance was divided into three phases: Switching (first trial after receiving the switch cue), hypothesis testing (subsequent trials through the last error trial), and rule application (correct responding after the rule was learned). We used both univariate analysis to characterize activity occurring within specific regions of the brain, and a multivariate method, constrained principal component analysis for fMRI (fMRI-CPCA), to investigate how distributed regions coordinate to subserve different processes. As hypothesized, switching was subserved by a limbic network including the ventral striatum, thalamus, and parahippocampal gyrus, in conjunction with cortical salience network regions including the anterior cingulate and frontoinsular cortex. Activity in the ventral striatum was associated with switching regardless of how switching was cued; visually cued shifts were associated with additional visual cortical activity. After switching, as subjects moved into the hypothesis testing phase, a broad fronto-parietal-striatal network (associated with the cognitive control, dorsal attention, and salience networks) increased in activity. This network was sensitive to rule learning speed, with greater extended activity for the slowest

  19. Developing a New HSR Switching Node (SwitchBox for Improving Traffic Performance in HSR Networks

    Directory of Open Access Journals (Sweden)

    Nguyen Xuan Tien

    2016-01-01

    Full Text Available High availability is crucial for industrial Ethernet networks as well as Ethernet-based control systems such as automation networks and substation automation systems (SAS. Since standard Ethernet does not support fault tolerance capability, the high availability of Ethernet networks can be increased by using redundancy protocols. Various redundancy protocols for Ethernet networks have been developed and standardized, such as rapid spanning tree protocol (RSTP, media redundancy protocol (MRP, parallel redundancy protocol (PRP, high-availability seamless redundancy (HSR and others. RSTP and MRP have switchover delay drawbacks. PRP provides zero recovery time, but requires a duplicate network infrastructure. HSR operation is similar to PRP, but HSR uses a single network. However, the standard HSR protocol is mainly applied to ring-based topologies and generates excessively unnecessary redundant traffic in the network. In this paper, we develop a new switching node for the HSR protocol, called SwitchBox, which is used in HSR networks in order to support any network topology and significantly reduce redundant network traffic, including unicast, multicast and broadcast traffic, compared with standard HSR. By using the SwitchBox, HSR not only provides seamless communications with zero switchover time in case of failure, but it is also easily applied to any network topology and significantly reduces unnecessary redundant traffic in HSR networks.

  20. Load balancing in OCDM optical packet switched networks

    Science.gov (United States)

    Yun, Ling; Qiu, Kun; Jiang, JIhai; Li, Yanqiu

    2008-11-01

    Optical packet switching (OPS), which transfers the switching function from electrical domain to optical domain and provides the smallest switching granularity, is the most potential candidate of switching form in the future optical networks. Optical code division multiplexing (OCDM) is the mostly practical all-optical processing technology at the state of the art. The experiments of optical packet switching with optical code (OC) label have demonstrated the switching capability and advantages. But the timing of erasing and inserting label, which is similar with the bit-serial label processing, is the stringent requirement of this scheme. OCDM optical packet switching, which encodes the payload directly and removes the label when the payload is recovered at the decoder, has no stringent timing requirement. Multiple access interference (MAI) is the main factor degrading the performance of OCDM optical packet-switched networks. In this paper, the effects of MAI are studied at the end of optical label path where the packets experience multiple hops. For eliminating the end-to-end BER, the optical label paths need to be established in an optimum way and the load are required to be balanced. One load-balancing algorithm based on the end-to-end BER of OCDM path is proposed to improve the network performance.

  1. Few-shot learning in deep networks through global prototyping.

    Science.gov (United States)

    Blaes, Sebastian; Burwick, Thomas

    2017-10-01

    Training a deep convolution neural network (CNN) to succeed in visual object classification usually requires a great number of examples. Here, starting from such a pre-learned CNN, we study the task of extending the network to classify additional categories on the basis of only few examples ("few-shot learning"). We find that a simple and fast prototype-based learning procedure in the global feature layers ("Global Prototype Learning", GPL) leads to some remarkably good classification results for a large portion of the new classes. It requires only up to ten examples for the new classes to reach a plateau in performance. To understand this few-shot learning performance resulting from GPL as well as the performance of the original network, we use the t-SNE method (Maaten and Hinton, 2008) to visualize clusters of object category examples. This reveals the strong connection between classification performance and data distribution and explains why some new categories only need few examples for learning while others resist good classification results even when trained with many more examples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Stabilization Strategies of Supply Networks with Stochastic Switched Topology

    Directory of Open Access Journals (Sweden)

    Shukai Li

    2013-01-01

    Full Text Available In this paper, a dynamical supply networks model with stochastic switched topology is presented, in which the stochastic switched topology is dependent on a continuous time Markov process. The goal is to design the state-feedback control strategies to stabilize the dynamical supply networks. Based on Lyapunov stability theory, sufficient conditions for the existence of state feedback control strategies are given in terms of matrix inequalities, which ensure the robust stability of the supply networks at the stationary states and a prescribed H∞ disturbance attenuation level with respect to the uncertain demand. A numerical example is given to illustrate the effectiveness of the proposed method.

  3. Bipolar resistive switching behaviors of ITO nanowire networks

    Directory of Open Access Journals (Sweden)

    Qiang Li

    2016-02-01

    Full Text Available We have fabricated indium tin oxide (ITO nanowire (NW networks on aluminum electrodes using electron beam evaporation. The Ag/ITO-NW networks/Al capacitor exhibits bipolar resistive switching behavior. The resistive switching characteristics of ITO-NW networks are related to the morphology of NWs. The x-ray photoelectron spectroscopy was used to obtain the chemical nature from the NWs surface, investigating the oxygen vacancy state. A stable switching voltages and a clear memory window were observed in needle-shaped NWs. The ITO-NW networks can be used as a new two-dimensional metal oxide material for the fabrication of high-density memory devices.

  4. Technical report on prototype intelligent network flow optimization (INFLO) dynamic speed harmonization and queue warning.

    Science.gov (United States)

    2015-06-01

    This Technical Report on Prototype Intelligent Network Flow Optimization (INFLO) Dynamic Speed Harmonization and : Queue Warning is the final report for the project. It describes the prototyping, acceptance testing and small-scale : demonstration of ...

  5. Network switching strategy for energy conservation in heterogeneous networks.

    Science.gov (United States)

    Song, Yujae; Choi, Wooyeol; Baek, Seungjae

    2017-01-01

    In heterogeneous networks (HetNets), the large-scale deployment of small base stations (BSs) together with traditional macro BSs is an economical and efficient solution that is employed to address the exponential growth in mobile data traffic. In dense HetNets, network switching, i.e., handovers, plays a critical role in connecting a mobile terminal (MT) to the best of all accessible networks. In the existing literature, a handover decision is made using various handover metrics such as the signal-to-noise ratio, data rate, and movement speed. However, there are few studies on handovers that focus on energy efficiency in HetNets. In this paper, we propose a handover strategy that helps to minimize energy consumption at BSs in HetNets without compromising the quality of service (QoS) of each MT. The proposed handover strategy aims to capture the effect of the stochastic behavior of handover parameters and the expected energy consumption due to handover execution when making a handover decision. To identify the validity of the proposed handover strategy, we formulate a handover problem as a constrained Markov decision process (CMDP), by which the effects of the stochastic behaviors of handover parameters and consequential handover energy consumption can be accurately reflected when making a handover decision. In the CMDP, the aim is to minimize the energy consumption to service an MT over the lifetime of its connection, and the constraint is to guarantee the QoS requirements of the MT given in terms of the transmission delay and call-dropping probability. We find an optimal policy for the CMDP using a combination of the Lagrangian method and value iteration. Simulation results verify the validity of the proposed handover strategy.

  6. Network switching strategy for energy conservation in heterogeneous networks.

    Directory of Open Access Journals (Sweden)

    Yujae Song

    Full Text Available In heterogeneous networks (HetNets, the large-scale deployment of small base stations (BSs together with traditional macro BSs is an economical and efficient solution that is employed to address the exponential growth in mobile data traffic. In dense HetNets, network switching, i.e., handovers, plays a critical role in connecting a mobile terminal (MT to the best of all accessible networks. In the existing literature, a handover decision is made using various handover metrics such as the signal-to-noise ratio, data rate, and movement speed. However, there are few studies on handovers that focus on energy efficiency in HetNets. In this paper, we propose a handover strategy that helps to minimize energy consumption at BSs in HetNets without compromising the quality of service (QoS of each MT. The proposed handover strategy aims to capture the effect of the stochastic behavior of handover parameters and the expected energy consumption due to handover execution when making a handover decision. To identify the validity of the proposed handover strategy, we formulate a handover problem as a constrained Markov decision process (CMDP, by which the effects of the stochastic behaviors of handover parameters and consequential handover energy consumption can be accurately reflected when making a handover decision. In the CMDP, the aim is to minimize the energy consumption to service an MT over the lifetime of its connection, and the constraint is to guarantee the QoS requirements of the MT given in terms of the transmission delay and call-dropping probability. We find an optimal policy for the CMDP using a combination of the Lagrangian method and value iteration. Simulation results verify the validity of the proposed handover strategy.

  7. Synchronization of Switched Interval Networks and Applications to Chaotic Neural Networks

    Directory of Open Access Journals (Sweden)

    Jinde Cao

    2013-01-01

    Full Text Available This paper investigates synchronization problem of switched delay networks with interval parameters uncertainty, based on the theories of the switched systems and drive-response technique, a mathematical model of the switched interval drive-response error system is established. Without constructing Lyapunov-Krasovskii functions, introducing matrix measure method for the first time to switched time-varying delay networks, combining Halanay inequality technique, synchronization criteria are derived for switched interval networks under the arbitrary switching rule, which are easy to verify in practice. Moreover, as an application, the proposed scheme is then applied to chaotic neural networks. Finally, numerical simulations are provided to illustrate the effectiveness of the theoretical results.

  8. Free-space optical switching core for storage area network

    Science.gov (United States)

    Zhang, Fan; Collings, Neil; Crossland, William A.; Wilkinson, Timothy D.; Fan, Mark; Taghizadeh, Mohammad R.; Waddie, Andrew

    2005-02-01

    Storage Area Network (SAN) has gradually developed as the demand for storage capacity and fast access has increased. The traditional way of attaching storage directly to the servers over a SCSI bus has limited scalability. Several drawbacks and limitations have turned up. Switched Fibre Channel SAN resolves all of these issues. In this paper, the architecture of the switch fabric for the SAN is discussed. The complete design of the free-space optical switching core based on the diffractive element and the PLZT shutter is proposed.

  9. Observability of Automata Networks: Fixed and Switching Cases.

    Science.gov (United States)

    Li, Rui; Hong, Yiguang; Wang, Xingyuan

    2017-03-10

    Automata networks are a class of fully discrete dynamical systems, which have received considerable interest in various different areas. This brief addresses the observability of automata networks and switched automata networks in a unified framework, and proposes simple necessary and sufficient conditions for observability. The results are achieved by employing methods from symbolic computation, and are suited for implementation using computer algebra systems. Several examples are presented to demonstrate the application of the results.

  10. Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch

    Directory of Open Access Journals (Sweden)

    Tao Huang

    2016-01-01

    Full Text Available Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture.

  11. Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch.

    Science.gov (United States)

    Huang, Tao; Yan, Siyu; Yang, Fan; Pan, Tian; Liu, Jiang

    2016-01-19

    Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture.

  12. Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch

    Science.gov (United States)

    Huang, Tao; Yan, Siyu; Yang, Fan; Pan, Tian; Liu, Jiang

    2016-01-01

    Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture. PMID:26797616

  13. Prototyping and Simulation of Robot Group Intelligence using Kohonen Networks.

    Science.gov (United States)

    Wang, Zhijun; Mirdamadi, Reza; Wang, Qing

    2016-01-01

    Intelligent agents such as robots can form ad hoc networks and replace human being in many dangerous scenarios such as a complicated disaster relief site. This project prototypes and builds a computer simulator to simulate robot kinetics, unsupervised learning using Kohonen networks, as well as group intelligence when an ad hoc network is formed. Each robot is modeled using an object with a simple set of attributes and methods that define its internal states and possible actions it may take under certain circumstances. As the result, simple, reliable, and affordable robots can be deployed to form the network. The simulator simulates a group of robots as an unsupervised learning unit and tests the learning results under scenarios with different complexities. The simulation results show that a group of robots could demonstrate highly collaborative behavior on a complex terrain. This study could potentially provide a software simulation platform for testing individual and group capability of robots before the design process and manufacturing of robots. Therefore, results of the project have the potential to reduce the cost and improve the efficiency of robot design and building.

  14. Prototyping

    OpenAIRE

    Corsín Jiménez, Alberto

    2017-01-01

    The prototyping of method calls for, at a minimum, three operations of design: rethinking the proprietary and legal economy of research; rethinking the frontiers that separate those who use methods from those to whom methods are applied to; designing infrastructures of apprenticeships for every problem.

  15. Integrative network biology: graph prototyping for co-expression cancer networks.

    Directory of Open Access Journals (Sweden)

    Karl G Kugler

    Full Text Available Network-based analysis has been proven useful in biologically-oriented areas, e.g., to explore the dynamics and complexity of biological networks. Investigating a set of networks allows deriving general knowledge about the underlying topological and functional properties. The integrative analysis of networks typically combines networks from different studies that investigate the same or similar research questions. In order to perform an integrative analysis it is often necessary to compare the properties of matching edges across the data set. This identification of common edges is often burdensome and computational intensive. Here, we present an approach that is different from inferring a new network based on common features. Instead, we select one network as a graph prototype, which then represents a set of comparable network objects, as it has the least average distance to all other networks in the same set. We demonstrate the usefulness of the graph prototyping approach on a set of prostate cancer networks and a set of corresponding benign networks. We further show that the distances within the cancer group and the benign group are statistically different depending on the utilized distance measure.

  16. Analyzing Nonblocking Switching Networks using Linear Programming (Duality)

    CERN Document Server

    Ngo, Hung Q; Le, Anh N; Nguyen, Thanh-Nhan

    2012-01-01

    The main task in analyzing a switching network design (including circuit-, multirate-, and photonic-switching) is to determine the minimum number of some switching components so that the design is non-blocking in some sense (e.g., strict- or wide-sense). We show that, in many cases, this task can be accomplished with a simple two-step strategy: (1) formulate a linear program whose optimum value is a bound for the minimum number we are seeking, and (2) specify a solution to the dual program, whose objective value by weak duality immediately yields a sufficient condition for the design to be non-blocking. We illustrate this technique through a variety of examples, ranging from circuit to multirate to photonic switching, from unicast to $f$-cast and multicast, and from strict- to wide-sense non-blocking. The switching architectures in the examples are of Clos-type and Banyan-type, which are the two most popular architectural choices for designing non-blocking switching networks. To prove the result in the multir...

  17. Secure Group Formation Protocol for a Medical Sensor Network Prototype

    DEFF Research Database (Denmark)

    Andersen, Jacob

    2009-01-01

    Designing security mechanisms such as privacy and access control for medical sensor networks is a challenging task; as such systems may be operated very frequently, at a quick pace, and at times in emergency situations. Understandably, clinicians hold extra unproductive tasks in low regard......, and experience from user workshops and observations of clinicians at work on a hospital ward show that if the security mechanisms are not well designed, the technology is either rejected altogether, or they are circumvented leaving the system wide open to attacks. Our work targets the problem of designing...... wireless sensors to be both secure and usable by exploring different solutions on a fully functional prototype platform. In this paper, we present an Elliptic Curve Cryptography (ECC) based protocol, which offers fully secure sensor set-up in a few seconds on standard (Telos) hardware. We evaluate...

  18. Switched Internetwork: a New Networking Paradigm

    Science.gov (United States)

    Miranda, Jose E.

    Today, internetworking is undergoing significant change, driven primarily by business demands, the need to support new applications, and by ongoing advances in communications technology. As networks evolve in response to these forces of change, the challenge is to provide increased bandwidth in a scalable fashion, while also delivering class of service support for new multimedia applications. It is also important to build a flexible networking infrastructure that can accommodate the constant changes businesses undergo, and that simplifies the administration of user moves, adds and changes, while reducing the complexity associated with managing the network. Today's enterprise-wide internetworks are running mission-critical applications, and cannot be used as testbeds for trying out new technology. Consequently, it is essential that the new network maintain the highest levels of availability and reliability.

  19. On-board congestion control for satellite packet switching networks

    Science.gov (United States)

    Chu, Pong P.

    1991-01-01

    It is desirable to incorporate packet switching capability on-board for future communication satellites. Because of the statistical nature of packet communication, incoming traffic fluctuates and may cause congestion. Thus, it is necessary to incorporate a congestion control mechanism as part of the on-board processing to smooth and regulate the bursty traffic. Although there are extensive studies on congestion control for both baseband and broadband terrestrial networks, these schemes are not feasible for space based switching networks because of the unique characteristics of satellite link. Here, we propose a new congestion control method for on-board satellite packet switching. This scheme takes into consideration the long propagation delay in satellite link and takes advantage of the the satellite's broadcasting capability. It divides the control between the ground terminals and satellite, but distributes the primary responsibility to ground terminals and only requires minimal hardware resource on-board satellite.

  20. Network Architecture of a Packet-switched WDM

    NARCIS (Netherlands)

    Dey, D.; Koonen, A.M.J.; Salvador, M.R.

    2000-01-01

    We propose a packet-switched WDM slotted ring network with destination release. The total bandwidth of each channel is divided into a fixed number of equal-sized slots. The nodes are equipped with fixed transmitters and tunable receivers. Control information, which is transmitted on a specific

  1. Stream Traffic Communication in Packet Switched Networks,

    Science.gov (United States)

    1977-08-01

    Currently, the interconnection of surh networks [ McKe 74a] and the standardization of protocols [Pouz 75), (Hove 76) are each of considerable interest in the...clear that failures do occur in practice. Long term monitoring of the ARPANET [ McKe 74) shows a mean time between failures (MTBF) of 431 hours for Lines...D. C.) [ McKe 74) McKenzie, A. A. Letter to S. D. Crocker. 16 Janu- ary 1974. [ McKe 74a] McKenzie, A. M. "Some Computer Network Intercon- nection

  2. Switched DWDM ethernet passive optical networks

    NARCIS (Netherlands)

    Roy, R.; Roeloffzen, C.G.H.; van Etten, Wim

    2006-01-01

    The IEEE Ethernet Passive Optical Networks (EPON) standard is a leading Time Division Multiplex (TDM) standard for PONs. The paper investigates the operation of an EPON based system in a Dense Wavelength Division Multiplex (DWDM) environment. It extends the concept of a multi-wavelength system from

  3. Robust network topologies for generating switch-like cellular responses.

    Directory of Open Access Journals (Sweden)

    Najaf A Shah

    2011-06-01

    Full Text Available Signaling networks that convert graded stimuli into binary, all-or-none cellular responses are critical in processes ranging from cell-cycle control to lineage commitment. To exhaustively enumerate topologies that exhibit this switch-like behavior, we simulated all possible two- and three-component networks on random parameter sets, and assessed the resulting response profiles for both steepness (ultrasensitivity and extent of memory (bistability. Simulations were used to study purely enzymatic networks, purely transcriptional networks, and hybrid enzymatic/transcriptional networks, and the topologies in each class were rank ordered by parametric robustness (i.e., the percentage of applied parameter sets exhibiting ultrasensitivity or bistability. Results reveal that the distribution of network robustness is highly skewed, with the most robust topologies clustering into a small number of motifs. Hybrid networks are the most robust in generating ultrasensitivity (up to 28% and bistability (up to 18%; strikingly, a purely transcriptional framework is the most fragile in generating either ultrasensitive (up to 3% or bistable (up to 1% responses. The disparity in robustness among the network classes is due in part to zero-order ultrasensitivity, an enzyme-specific phenomenon, which repeatedly emerges as a particularly robust mechanism for generating nonlinearity and can act as a building block for switch-like responses. We also highlight experimentally studied examples of topologies enabling switching behavior, in both native and synthetic systems, that rank highly in our simulations. This unbiased approach for identifying topologies capable of a given response may be useful in discovering new natural motifs and in designing robust synthetic gene networks.

  4. Principle and verification of novel optical virtual private networks over multiprotocol label switching/optical packet switching networks

    Science.gov (United States)

    Zhang, Chongfu; Wang, Zhengsuan; Jin, Wei; Qiu, Kun

    2012-11-01

    A novel realization method of the optical virtual private networks (OVPN) over multiprotocol label switching/optical packet switching (MPLS/OPS) networks is proposed. In this scheme, the introduction of MPLS control plane makes OVPN over OPS networks more reliable and easier; OVPN makes use of the concept of high reconfiguration of light-paths offered by MPLS, to set up secure tunnels of high bandwidth across intelligent OPS networks. Through resource management, the signal mechanism, connection control, and the architecture of the creation and maintenance of OVPN are efficiently realized. We also present an OVPN architecture with two traffic priorities, which is used to analyze the capacity, throughput, delay time of the proposed networks, and the packet loss rate performance of the OVPN over MPLS/OPS networks based on full mesh topology. The results validate the applicability of such reliable connectivity to high quality services in the OVPN over MPLS/OPS networks. Along with the results, the feasibility of the approach as the basis for the next generation networks is demonstrated and discussed.

  5. The Fragility of Interdependency: Coupled Networks Switching Phenomena

    Science.gov (United States)

    Stanley, H. Eugene

    2013-03-01

    Recent disasters ranging from abrupt financial ``flash crashes'' and large-scale power outages to sudden death among the elderly dramatically exemplify the fact that the most dangerous vulnerability is hiding in the many interdependencies among different networks. In the past year, we have quantified failures in model of interconnected networks, and demonstrated the need to consider mutually dependent network properties in designing resilient systems. Specifically, we have uncovered new laws governing the nature of switching phenomena in coupled networks, and found that phenomena that are continuous ``second order'' phase transitions in isolated networks become discontinuous abrupt ``first order'' transitions in interdependent networks [S. V. Buldyrev, R. Parshani, G. Paul, H. E. Stanley, and S. Havlin, ``Catastrophic Cascade of Failures in Interdependent Networks,'' Nature 464, 1025 (2010); J. Gao, S. V. Buldyrev, H. E. Stanley, and S. Havlin, ``Novel Behavior of Networks Formed from Interdependent Networks,'' Nature Physics 8, 40 (2012). We conclude by discussing the network basis for understanding sudden death in the elderly, and the possibility that financial ``flash crashes'' are not unlike the catastrophic first-order failure incidents occurring in coupled networks. Specifically, we study the coupled networks that are responsible for financial fluctuations. It appears that ``trend switching phenomena'' that we uncover are remarkably independent of the scale over which they are analyzed. For example, we find that the same laws governing the formation and bursting of the largest financial bubbles also govern the tiniest finance bubbles, over a factor of 1,000,000,000 in time scale [T. Preis, J. Schneider, and H. E. Stanley, ``Switching Processes in Financial Markets,'' Proc. Natl. Acad. Sci. USA 108, 7674 (2011); T. Preis and H. E. Stanley, ``Bubble Trouble: Can a Law Describe Bubbles and Crashes in Financial Markets?'' Physics World 24, No. 5, 29 (May 2011

  6. Column Generation for Transmission Switching of Electricity Networks with Unit Commitment

    OpenAIRE

    Villumsen, Jonas Christoffer; Philpott, Andy B.

    2011-01-01

    This paper presents the problem of finding the minimum cost dispatch and commitment of power generation units in a transmission network with active switching.We use the term active switching to denote the use of switches to optimize network topology in an operational context. We propose a Dantzig-Wolfe reformulation and a novel column generation framework to solve the problem efficiently. Preliminary results are presented for the IEEE-118 bus network with 19 generator units. Active switching ...

  7. Quantum key based burst confidentiality in optical burst switched networks.

    Science.gov (United States)

    Balamurugan, A M; Sivasubramanian, A

    2014-01-01

    The optical burst switching (OBS) is an emergent result to the technology concern that could achieve a feasible network in future. They are endowed with the ability to meet the bandwidth requirement of those applications that require intensive bandwidth. There are more domains opening up in the OBS that evidently shows their advantages and their capability to face the future network traffic. However, the concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution, and quality of service (QoS). This paper deals with employing RC4 (stream cipher) to encrypt and decrypt bursts thereby ensuring the confidentiality of the burst. Although the use of AES algorithm has already been proposed for the same issue, by contrasting the two algorithms under the parameters of burst encryption and decryption time, end-to-end delay, it was found that RC4 provided better results. This paper looks to provide a better solution for the confidentiality of the burst in OBS networks.

  8. Quantum Key Based Burst Confidentiality in Optical Burst Switched Networks

    Directory of Open Access Journals (Sweden)

    A. M. Balamurugan

    2014-01-01

    Full Text Available The optical burst switching (OBS is an emergent result to the technology concern that could achieve a feasible network in future. They are endowed with the ability to meet the bandwidth requirement of those applications that require intensive bandwidth. There are more domains opening up in the OBS that evidently shows their advantages and their capability to face the future network traffic. However, the concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution, and quality of service (QoS. This paper deals with employing RC4 (stream cipher to encrypt and decrypt bursts thereby ensuring the confidentiality of the burst. Although the use of AES algorithm has already been proposed for the same issue, by contrasting the two algorithms under the parameters of burst encryption and decryption time, end-to-end delay, it was found that RC4 provided better results. This paper looks to provide a better solution for the confidentiality of the burst in OBS networks.

  9. A Prototype Network for Remote Sensing Validation in China

    Directory of Open Access Journals (Sweden)

    Mingguo Ma

    2015-04-01

    Full Text Available Validation is an essential and important step before the application of remote sensing products. This paper introduces a prototype of the validation network for remote sensing products in China (VRPC. The VRPC aims to improve remote sensing products at a regional scale in China. These improvements will enhance the applicability of the key remote sensing products in understanding and interpretation of typical land surface processes in China. The framework of the VRPC is introduced first, including its four basic components. Then, the basic selection principles of the observation sites are described, and the principles for the validation of the remote sensing products are established. The VRPC will be realized in stages. In the first stage, four stations that have improved remote sensing observation facilities have been incorporated according to the selection principles. Certain core observation sites have been constructed at these stations. Next the Heihe Station is introduced in detail as an example. The three levels of observation (the research base, pixel-scale validation sites, and regional coverage adopted by the Heihe Station are carefully explained. The pixel-scale validation sites with nested multi-scale observation systems in this station are the most unique feature, and these sites aim to solve some key scientific problems associated with remote sensing product validation (e.g., the scale effect and scale transformation. Multi-year of in situ measurements will ensure the high accuracy and inter-annual validity of the land products, which will provide dynamic regional monitoring and simulation capabilities in China. The observation sites of the VRPC are open, with the goal of increasing cooperation and exchange with global programs.

  10. Noise-induced polarization switching in complex networks

    Science.gov (United States)

    Haerter, Jan O.; Díaz-Guilera, Albert; Serrano, M. Ángeles

    2017-04-01

    The combination of bistability and noise is ubiquitous in complex systems, from biology to social interactions, and has important implications for their functioning and resilience. Here we use a simple three-state dynamical process, in which nodes go from one pole to another through an intermediate state, to show that noise can induce polarization switching in bistable systems if dynamical correlations are significant. In large, fully connected networks, where dynamical correlations can be neglected, increasing noise yields a collapse of bistability to an unpolarized configuration where the three possible states of the nodes are equally likely. In contrast, increased noise induces abrupt and irreversible polarization switching in sparsely connected networks. In multiplexes, where each layer can have a different polarization tendency, one layer is dominant and progressively imposes its polarization state on the other, offsetting or promoting the ability of noise to switch its polarization. Overall, we show that the interplay of noise and dynamical correlations can yield discontinuous transitions between extremes, which cannot be explained by a simple mean-field description.

  11. FPGA platform for prototyping and evaluation of neural network automotive applications

    Science.gov (United States)

    Aranki, N.; Tawel, R.

    2002-01-01

    In this paper we present an FPGA based reconfigurable computing platform for prototyping and evaluation of advanced neural network based applications for control and diagnostics in an automotive sub-systems.

  12. A Mercury Frequency Standard Engineering Prototype for the NASA Deep Space Network

    Science.gov (United States)

    Tjoelker, R. L.; Bricker, C.; Diener, W.; Hamell, R. L.; Kirk, A.; Kuhnle, P.; Maleki, L.; Prestage, J. D.; Santiago, D.; Seidel, D.; hide

    1996-01-01

    An engineering prototype linear ion trap frequency standar (LITS-4) using (sup 199)Hg+ is operational and currently under test for NASA's Deep Space Network (DSN). The DSN requires high stability and reliability with continuous operation.

  13. Switch-like Transitions Insulate Network Motifs to Modularize Biological Networks.

    Science.gov (United States)

    Atay, Oguzhan; Doncic, Andreas; Skotheim, Jan M

    2016-08-01

    Cellular decisions are made by complex networks that are difficult to analyze. Although it is common to analyze smaller sub-networks known as network motifs, it is unclear whether this is valid, because these motifs are embedded in complex larger networks. Here, we address the general question of modularity by examining the S. cerevisiae pheromone response. We demonstrate that the feedforward motif controlling the cell-cycle inhibitor Far1 is insulated from cell-cycle dynamics by the positive feedback switch that drives reentry to the cell cycle. Before cells switch on positive feedback, the feedforward motif model predicts the behavior of the larger network. Conversely, after the switch, the feedforward motif is dismantled and has no discernable effect on the cell cycle. When insulation is broken, the feedforward motif no longer predicts network behavior. This work illustrates how, despite the interconnectivity of networks, the activity of motifs can be insulated by switches that generate well-defined cellular states. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Emergence of Slow-Switching Assemblies in Structured Neuronal Networks.

    Directory of Open Access Journals (Sweden)

    Michael T Schaub

    2015-07-01

    Full Text Available Unraveling the interplay between connectivity and spatio-temporal dynamics in neuronal networks is a key step to advance our understanding of neuronal information processing. Here we investigate how particular features of network connectivity underpin the propensity of neural networks to generate slow-switching assembly (SSA dynamics, i.e., sustained epochs of increased firing within assemblies of neurons which transition slowly between different assemblies throughout the network. We show that the emergence of SSA activity is linked to spectral properties of the asymmetric synaptic weight matrix. In particular, the leading eigenvalues that dictate the slow dynamics exhibit a gap with respect to the bulk of the spectrum, and the associated Schur vectors exhibit a measure of block-localization on groups of neurons, thus resulting in coherent dynamical activity on those groups. Through simple rate models, we gain analytical understanding of the origin and importance of the spectral gap, and use these insights to develop new network topologies with alternative connectivity paradigms which also display SSA activity. Specifically, SSA dynamics involving excitatory and inhibitory neurons can be achieved by modifying the connectivity patterns between both types of neurons. We also show that SSA activity can occur at multiple timescales reflecting a hierarchy in the connectivity, and demonstrate the emergence of SSA in small-world like networks. Our work provides a step towards understanding how network structure (uncovered through advancements in neuroanatomy and connectomics can impact on spatio-temporal neural activity and constrain the resulting dynamics.

  15. Emergence of Slow-Switching Assemblies in Structured Neuronal Networks.

    Science.gov (United States)

    Schaub, Michael T; Billeh, Yazan N; Anastassiou, Costas A; Koch, Christof; Barahona, Mauricio

    2015-07-01

    Unraveling the interplay between connectivity and spatio-temporal dynamics in neuronal networks is a key step to advance our understanding of neuronal information processing. Here we investigate how particular features of network connectivity underpin the propensity of neural networks to generate slow-switching assembly (SSA) dynamics, i.e., sustained epochs of increased firing within assemblies of neurons which transition slowly between different assemblies throughout the network. We show that the emergence of SSA activity is linked to spectral properties of the asymmetric synaptic weight matrix. In particular, the leading eigenvalues that dictate the slow dynamics exhibit a gap with respect to the bulk of the spectrum, and the associated Schur vectors exhibit a measure of block-localization on groups of neurons, thus resulting in coherent dynamical activity on those groups. Through simple rate models, we gain analytical understanding of the origin and importance of the spectral gap, and use these insights to develop new network topologies with alternative connectivity paradigms which also display SSA activity. Specifically, SSA dynamics involving excitatory and inhibitory neurons can be achieved by modifying the connectivity patterns between both types of neurons. We also show that SSA activity can occur at multiple timescales reflecting a hierarchy in the connectivity, and demonstrate the emergence of SSA in small-world like networks. Our work provides a step towards understanding how network structure (uncovered through advancements in neuroanatomy and connectomics) can impact on spatio-temporal neural activity and constrain the resulting dynamics.

  16. Preferred access in packet-switching radio networks

    Science.gov (United States)

    Shacham, N.

    Channel-access protocols that provide prioritized access to a common channel in a packet switching network are considered. The elements of such protocols are discussed and a specific protocol that integrates two types of packets is proposed. A probabilistic model of the protocol is presented, and its analysis yields the throughput-delay characteristics of the two classes and the interaction between them. The model is analyzed by a method similar to the one used in priority queues; this method allows consideration of each class separately, thus reducing the computational effort substantially.

  17. Routing Aware Switch Hardware Customization for Networks on Chips

    OpenAIRE

    Meloni, Paolo; Murali, Srinivasan; Carta, Salvatore; Camplani, Massimo; Raffo, Luigi; Micheli, Giovanni,

    2006-01-01

    Networks on Chip (NoC) has been proposed as a scalable and reusable solution for interconnecting the ever- growing number of processor/memory cores on a single silicon die. As the hardware complexity of a NoC is significant, methods for designing a NoC with low hardware overhead, matching the application requirements are essential. In this work, we present a method for reducing the hardware complexity of the NoC by automatically configuring the architecture of the NoC switches to suit the app...

  18. Earlier and more distributed neural networks for bilinguals than monolinguals during switching.

    Science.gov (United States)

    Timmer, Kalinka; Grundy, John G; Bialystok, Ellen

    2017-11-01

    The present study investigated processing differences between young adults who were English monolinguals or English-French bilinguals on a task- and language-switching paradigm. The mechanisms responsible for task switching and language switching were investigated using electrophysiological (EEG) measures. In nonverbal task switching, monolinguals and bilinguals demonstrated equivalent behavioral mixing (pure vs. repeat) and switching (repeat vs. switch) costs, but bilinguals were more accurate in the mixed blocks. Bilinguals used a more distributed neural network than monolinguals that captured the nonverbal mixing effect and showed earlier discrimination for the switching effect in the ERPs. In language switching, more distributed networks for bilinguals than monolinguals were found for the switching effect. The scalp distributions revealed more overlap between task switching and language switching for bilinguals than monolinguals. For switch costs, both groups showed P3/LPC modulations in both tasks, but bilinguals showed extended activation to central regions for both switching tasks. For mixing costs, both groups revealed modulations of the N2 but only bilinguals showed extended activation to the occipital region. Overall bilinguals revealed more overlapping processing between task- and language-switching than monolinguals, consistent with the interpretation of integration of verbal and nonverbal control networks during early visual processing for bilinguals and later executive processing for monolinguals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. The salience network is responsible for switching between the default mode network and the central executive network: replication from DCM.

    Science.gov (United States)

    Goulden, Nia; Khusnulina, Aygul; Davis, Nicholas J; Bracewell, Robert M; Bokde, Arun L; McNulty, Jonathan P; Mullins, Paul G

    2014-10-01

    With the advent of new analysis methods in neuroimaging that involve independent component analysis (ICA) and dynamic causal modelling (DCM), investigations have focused on measuring both the activity and connectivity of specific brain networks. In this study we combined DCM with spatial ICA to investigate network switching in the brain. Using time courses determined by ICA in our dynamic causal models, we focused on the dynamics of switching between the default mode network (DMN), the network which is active when the brain is not engaging in a specific task, and the central executive network (CEN), which is active when the brain is engaging in a task requiring attention. Previous work using Granger causality methods has shown that regions of the brain which respond to the degree of subjective salience of a stimulus, the salience network, are responsible for switching between the DMN and the CEN (Sridharan et al., 2008). In this work we apply DCM to ICA time courses representing these networks in resting state data. In order to test the repeatability of our work we applied this to two independent datasets. This work confirms that the salience network drives the switching between default mode and central executive networks and that our novel technique is repeatable. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

  20. A rapid protection switching method in carrier ethernet ring networks

    Science.gov (United States)

    Yuan, Liang; Ji, Meng

    2008-11-01

    Abstract: Ethernet is the most important Local Area Network (LAN) technology since more than 90% data traffic in access layer is carried on Ethernet. From 10M to 10G, the improving Ethernet technology can be not only used in LAN, but also a good choice for MAN even WAN. MAN are always constructed in ring topology because the ring network could provide resilient path protection by using less resource (fibre or cable) than other network topologies. In layer 2 data networks, spanning tree protocol (STP) is always used to protect transmit link and preventing the formation of logic loop in networks. However, STP cannot guarantee the efficiency of service convergence when link fault happened. In fact, convergent time of networks with STP is about several minutes. Though Rapid Spanning Tree Protocol (RSTP) and Multi-Spanning Tree Protocol (MSTP) improve the STP technology, they still need a couple of seconds to achieve convergence, and can not provide sub-50ms protection switching. This paper presents a novel rapid ring protection method (RRPM) for carrier Ethernet. Unlike other link-fault detection method, it adopts distributed algorithm to detect link fault rapidly (sub-50ms). When networks restore from link fault, it can revert to the original working state. RRPM can provide single ring protection and interconnected ring protection without the formation of super loop. In normal operation, the master node blocks the secondary port for all non-RRPM Ethernet frames belonging to the given RRPM Ring, thereby avoiding a loop in the ring. When link fault happens, the node on which the failure happens moves from the "ring normal" state to the "ring fault" state. It also sends "link down" frame immediately to other nodes and blocks broken port and flushes its forwarding database. Those who receive "link down" frame will flush forwarding database and master node should unblock its secondary port. When the failure restores, the whole ring will revert to the normal state. That is

  1. Control of Stochastic and Induced Switching in Biophysical Networks

    Science.gov (United States)

    Wells, Daniel K.; Kath, William L.; Motter, Adilson E.

    2015-07-01

    Noise caused by fluctuations at the molecular level is a fundamental part of intracellular processes. While the response of biological systems to noise has been studied extensively, there has been limited understanding of how to exploit it to induce a desired cell state. Here we present a scalable, quantitative method based on the Freidlin-Wentzell action to predict and control noise-induced switching between different states in genetic networks that, conveniently, can also control transitions between stable states in the absence of noise. We apply this methodology to models of cell differentiation and show how predicted manipulations of tunable factors can induce lineage changes, and further utilize it to identify new candidate strategies for cancer therapy in a cell death pathway model. This framework offers a systems approach to identifying the key factors for rationally manipulating biophysical dynamics, and should also find use in controlling other classes of noisy complex networks.

  2. Multiservice Switching Networks with Overflow Links and Resource Reservation

    Directory of Open Access Journals (Sweden)

    Mariusz Głąbowski

    2016-01-01

    Full Text Available This paper proposes a new analytical model of a multiservice switching network with overflow links in the first stage and resource reservation for selected call classes in output directions. The proposed model assumes that both the overflow mechanism and the resource reservation mechanism can be used in a number of selected, or all, classes of calls. A particular attention is given to the way the effective availability parameter for networks with overflow links in the point-to-point selection mode is determined. The proposed model makes it possible to determine dependencies between the internal blocking probability, capacity of overflow links, and the number of reserved resources for call classes to be analysed. Simulation experiments confirm high accuracy of the proposed method and potential applications of the model in engineering issues.

  3. The Swiss Education and Research Network - SWITCH - Upgrades Optical Network to Transport 10 Gbps Using Sorrento Networks DWDM Platform

    CERN Multimedia

    2003-01-01

    "Sorrento Networks, a supplier of optical transport networking equipment for carriers and enterprises worldwide, today announced that SWITCH successfully completed 10 Gbps BER tests on the 220 km Zurich to Manno and 360 km Zurich to Geneva links in September and November 2003, using Sorrento's GigaMux DWDM system" (1/2 page).

  4. Software Switching for High Throughput Data Acquisition Networks

    CERN Document Server

    AUTHOR|(CDS)2089787; Lehmann Miotto, Giovanna

    The bursty many-to-one communication pattern, typical for data acquisition systems, is particularly demanding for commodity TCP/IP and Ethernet technologies. The problem arising from this pattern is widely known in the literature as \\emph{incast} and can be observed as TCP throughput collapse. It is a result of overloading the switch buffers, when a specific node in a network requests data from multiple sources. This will become even more demanding for future upgrades of the experiments at the Large Hadron Collider at CERN. It is questionable whether commodity TCP/IP and Ethernet technologies in their current form will be still able to effectively adapt to bursty traffic without losing packets due to the scarcity of buffers in the networking hardware. This thesis provides an analysis of TCP/IP performance in data acquisition networks and presents a novel approach to incast congestion in these networks based on software-based packet forwarding. Our first contribution lies in confirming the strong analogies bet...

  5. Hybrid Wavelength Routed and Optical Packet Switched Ring Networks for the Metropolitan Area Network

    DEFF Research Database (Denmark)

    Nord, Martin

    2005-01-01

    Increased data traffic in the metropolitan area network calls for new network architectures. This paper evaluates optical ring architectures based on optical packet switching, wavelength routing, and hybrid combinations of the two concepts. The evaluation includes overall throughput and fairness...... aspects in both uniform and unbalanced traffic scenarios, for both Poisson and bursty input traffic. Simulations show a trade-off between performance and complexity. Whilst the static wavelength routed optical network is a good solutions for uniform traffic, the proposed hybrid architectures are more...

  6. NEW BURST ASSEMBLY AND SCHEDULING TECHNIQUE FOR OPTICAL BURST SWITCHING NETWORKS

    OpenAIRE

    Kavitha, V.; V.Palanisamy

    2013-01-01

    The Optical Burst Switching is a new switching technology that efficiently utilizes the bandwidth in the optical layer. The key areas to be concentrated in Optical Burst Switching (OBS) networks are the burst assembly and burst scheduling i.e., assignment of wavelengths to the incoming bursts. This study presents a New Burst Assembly and Scheduling (NBAS) technique in a simultaneous multipath transmission for burst loss recovery in OBS networks. A Redundant Burst Segmentation (RBS) is used fo...

  7. Building a Reliable Onboard Network with Ethernet: A GSFC Prototype

    Science.gov (United States)

    Marquart, Jane

    2004-01-01

    This viewgraph presentation discusses the architecture of an Ethernet-based communication network for spacecraft. The presentation also contains information on data link reliability, PDU formats, and NIC/OS Measurements.

  8. Synchronization of Switched Neural Networks With Communication Delays via the Event-Triggered Control.

    Science.gov (United States)

    Wen, Shiping; Zeng, Zhigang; Chen, Michael Z Q; Huang, Tingwen

    2017-10-01

    This paper addresses the issue of synchronization of switched delayed neural networks with communication delays via event-triggered control. For synchronizing coupled switched neural networks, we propose a novel event-triggered control law which could greatly reduce the number of control updates for synchronization tasks of coupled switched neural networks involving embedded microprocessors with limited on-board resources. The control signals are driven by properly defined events, which depend on the measurement errors and current-sampled states. By using a delay system method, a novel model of synchronization error system with delays is proposed with the communication delays and event-triggered control in the unified framework for coupled switched neural networks. The criteria are derived for the event-triggered synchronization analysis and control synthesis of switched neural networks via the Lyapunov-Krasovskii functional method and free weighting matrix approach. A numerical example is elaborated on to illustrate the effectiveness of the derived results.

  9. Combining SDM-Based Circuit Switching with Packet Switching in a Router for On-Chip Networks

    Directory of Open Access Journals (Sweden)

    Angelo Kuti Lusala

    2012-01-01

    Full Text Available A Hybrid router architecture for Networks-on-Chip “NoC” is presented, it combines Spatial Division Multiplexing “SDM” based circuit switching and packet switching in order to efficiently and separately handle both streaming and best-effort traffic generated in real-time applications. Furthermore the SDM technique is combined with Time Division Multiplexing “TDM” technique in the circuit switching part in order to increase path diversity, thus improving throughput while sharing communication resources among multiple connections. Combining these two techniques allows mitigating the poor resource usage inherent to circuit switching. In this way Quality of Service “QoS” is easily provided for the streaming traffic through the circuit-switched sub-router while the packet-switched sub-router handles best-effort traffic. The proposed hybrid router architectures were synthesized, placed and routed on an FPGA. Results show that a practicable Network-on-Chip “NoC” can be built using the proposed router architectures. 7 × 7 mesh NoCs were simulated in SystemC. Simulation results show that the probability of establishing paths through the NoC increases with the number of sub-channels and has its highest value when combining SDM with TDM, thereby significantly reducing contention in the NoC.

  10. Management and development of local area network upgrade prototype

    Science.gov (United States)

    Fouser, T. J.

    1981-01-01

    Given the situation of having management and development users accessing a central computing facility and given the fact that these same users have the need for local computation and storage, the utilization of a commercially available networking system such as CP/NET from Digital Research provides the building blocks for communicating intelligent microsystems to file and print services. The major problems to be overcome in the implementation of such a network are the dearth of intelligent communication front-ends for the microcomputers and the lack of a rich set of management and software development tools.

  11. Exponential Synchronization of Stochastic Complex Dynamical Networks with Impulsive Perturbations and Markovian Switching

    Directory of Open Access Journals (Sweden)

    Wuneng Zhou

    2014-01-01

    Full Text Available This paper investigates the exponential synchronization problem of stochastic complex dynamical networks with impulsive perturbation and Markovian switching. The complex dynamical networks consist of κ modes, and the networks switch from one mode to another according to a Markovian chain with known transition probability. Based on the Lyapunov function method and stochastic analysis, by employing M-matrix approach, some sufficient conditions are presented to ensure the exponential synchronization of stochastic complex dynamical networks with impulsive perturbation and Markovian switching, and the upper bound of impulsive gain is evaluated. At the end of this paper, two numerical examples are included to show the effectiveness of our results.

  12. Delay Analysis of Networked Control Systems Based on 100 M Switched Ethernet

    Science.gov (United States)

    2014-01-01

    For the delay may degrade the performance of networked control systems, networked control systems based on 100 M switched Ethernet are proposed in this paper. According to the working principle of Ethernet switch, the formulas of the upper bound delay of the single-level switched Ethernet and the multiple-level switched Ethernet are deduced by the timing diagram method, and the values of the upper bound delay are also given. The key factors that influence the upper bound delay of switched Ethernet are analyzed; then, the characteristics of the upper bound delay are presented, which show that the delay induced by the single-level 100 M switched Ethernet has little effect on the performance of control systems, while the delay induced by the multiple-level 100 M switched Ethernet may meet the time requirements of all classes of control systems if the numbers of levels and the numbers of nodes connecting to switches are set properly. Finally, the performance of networked control systems is simulated by TrueTime, and the results further show the feasibility and superiority of 100 M switched Ethernet based networked control systems without modification of the network protocols. PMID:25003152

  13. Prototyping Service Discovery and Usage in Wireless Sensor Networks

    NARCIS (Netherlands)

    Marin Perianu, Raluca; Scholten, Johan; Havinga, Paul J.M.

    2007-01-01

    Heterogeneous Wireless Sensor Networks (WSNs) are envisioned to provide different types of services in an open and dynamic environment. This paper presents the design, implementation and evaluation of a service discovery and usage solution for heterogeneous WSNs. The users have the possibility to

  14. Switching synchronization in one-dimensional memristive networks: An exact solution

    Science.gov (United States)

    Slipko, V. A.; Pershin, Y. V.

    2017-12-01

    We study a switching synchronization phenomenon taking place in one-dimensional memristive networks when the memristors switch from the high- to low-resistance state. It is assumed that the distributions of threshold voltages and switching rates of memristors are arbitrary. Using the Laplace transform, a set of nonlinear equations describing the memristors dynamics is solved exactly, without any approximations. The time dependencies of memristances are found, and it is shown that the voltage falls across memristors are proportional to their threshold voltages. A compact expression for the network switching time is derived.

  15. Leader-Following Consensus of Multi-agent in Switching Networks with Time-Delay

    OpenAIRE

    Hui Yu; Gaoyang Liu; Yi Zhang

    2013-01-01

    This paper is devoted to the study of multi-agent consensus with a time-varying reference state in directed networks with both switching topology and constant time delay. Stability analysis is performed based on a proposed Lyapunov–Krasovskii function. Sufficient conditions based on linear matrix inequalities (LMIs) are given to guarantee multi-agent consensus on a time-vary reference state under arbitrary switching of the network topology even if the network communication is affected by time...

  16. A prototype implementation of a network-level intrusion detection system. Technical report number CS91-11

    Energy Technology Data Exchange (ETDEWEB)

    Heady, R.; Luger, G.F.; Maccabe, A.B.; Servilla, M.; Sturtevant, J. [New Mexico Univ., Albuquerque, NM (United States). Dept. of Computer Science

    1991-05-15

    This paper presents the implementation of a prototype network level intrusion detection system. The prototype system monitors base level information in network packets (source, destination, packet size, time, and network protocol), learning the normal patterns and announcing anomalies as they occur. The goal of this research is to determine the applicability of current intrusion detection technology to the detection of network level intrusions. In particular, the authors are investigating the possibility of using this technology to detect and react to worm programs.

  17. QKD-Based Secured Burst Integrity Design for Optical Burst Switched Networks

    Science.gov (United States)

    Balamurugan, A. M.; Sivasubramanian, A.; Parvathavarthini, B.

    2016-03-01

    The field of optical transmission has undergone numerous advancements and is still being researched mainly due to the fact that optical data transmission can be done at enormous speeds. It is quite evident that people prefer optical communication when it comes to large amount of data involving its transmission. The concept of switching in networks has matured enormously with several researches, architecture to implement and methods starting with Optical circuit switching to Optical Burst Switching. Optical burst switching is regarded as viable solution for switching bursts over networks but has several security vulnerabilities. However, this work exploited the security issues associated with Optical Burst Switching with respect to integrity of burst. This proposed Quantum Key based Secure Hash Algorithm (QKBSHA-512) with enhanced compression function design provides better avalanche effect over the conventional integrity algorithms.

  18. Mean-Square Exponential Synchronization of Stochastic Complex Dynamical Networks with Switching Topology by Impulsive Control

    Directory of Open Access Journals (Sweden)

    Xuefei Wu

    2013-01-01

    Full Text Available This paper investigates the mean-square exponential synchronization issues of delayed stochastic complex dynamical networks with switching topology and impulsive control. By using the Lyapunov functional method, impulsive control theory, and linear matrix inequality (LMI approaches, some sufficient conditions are derived to guarantee the mean-square exponential synchronization of delay complex dynamical network with switch topology, which are independent of the network size and switch topology. Numerical simulations are given to illustrate the effectiveness of the obtained results in the end.

  19. Identification of current attacks and their counter measures in Optical Burst Switched (OBS) network

    OpenAIRE

    Siddharth Singh Chouhan; Prof. Sanjay Sharma

    2012-01-01

    As day by day application grows internet requires large amount of bandwidth. Optical Burst Switching (OBS) is the next generation optical Internet with IP over WDM as the core architecture. It can achieve a balance between Optical Circuit Switching (OCS) and Optical Packet Switching (OPS). Optical network supports huge bandwidth and transmits data at an average rate of 50Tb/s. But we need to exploit the fiber’s huge bandwidth through WDM which is the current favorite multiplexing technology i...

  20. Column Generation for Transmission Switching of Electricity Networks with Unit Commitment

    DEFF Research Database (Denmark)

    Villumsen, Jonas Christoffer; Philpott, Andy B.

    2011-01-01

    This paper presents the problem of finding the minimum cost dispatch and commitment of power generation units in a transmission network with active switching.We use the term active switching to denote the use of switches to optimize network topology in an operational context. We propose a Dantzig......-Wolfe reformulation and a novel column generation framework to solve the problem efficiently. Preliminary results are presented for the IEEE-118 bus network with 19 generator units. Active switching is shown to reduce total cost by up to 15 % for a particular 24-hour period. Furthermore, the need for generator...... startups is reduced by 1. Instances with limited switching, some of which are intractable for commercial solvers, are shown to solve to optimality in reasonable time....

  1. Estimating switching costs of changing social networking sites

    OpenAIRE

    Nakamura, Akihiro

    2012-01-01

    This study's empirical analysis shows that the consumers' switching costs when changing SNS are less than that when changing BB service. SNS switching cost is estimated at JPY 944, while that in BB service is estimated at JPY 2864 (JPY 80 = USD 1 on 21st May 2012). According to these results, the switching cost of the former is approximately one-third of that of the latter. One of the reasons why SNS switching costs are smaller could be because of the current small number of friends on SNS. I...

  2. Delay-Dependent Stability Criteria of Uncertain Periodic Switched Recurrent Neural Networks with Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Xing Yin

    2011-01-01

    uncertain periodic switched recurrent neural networks with time-varying delays. When uncertain discrete-time recurrent neural network is a periodic system, it is expressed as switched neural network for the finite switching state. Based on the switched quadratic Lyapunov functional approach (SQLF and free-weighting matrix approach (FWM, some linear matrix inequality criteria are found to guarantee the delay-dependent asymptotical stability of these systems. Two examples illustrate the exactness of the proposed criteria.

  3. 47 CFR 68.110 - Compatibility of the public switched telephone network and terminal equipment.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Compatibility of the public switched telephone... Conditions on Use of Terminal Equipment § 68.110 Compatibility of the public switched telephone network and... maintain uninterrupted service. (c) Availability of inside wiring information. Any available technical...

  4. Optically triggered high voltage switch network and method for switching a high voltage

    Science.gov (United States)

    El-Sharkawi, Mohamed A.; Andexler, George; Silberkleit, Lee I.

    1993-01-19

    An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

  5. Stability analysis of switched stochastic neural networks with time-varying delays.

    Science.gov (United States)

    Wu, Xiaotai; Tang, Yang; Zhang, Wenbing

    2014-03-01

    This paper is concerned with the global exponential stability of switched stochastic neural networks with time-varying delays. Firstly, the stability of switched stochastic delayed neural networks with stable subsystems is investigated by utilizing the mathematical induction method, the piecewise Lyapunov function and the average dwell time approach. Secondly, by utilizing the extended comparison principle from impulsive systems, the stability of stochastic switched delayed neural networks with both stable and unstable subsystems is analyzed and several easy to verify conditions are derived to ensure the exponential mean square stability of switched delayed neural networks with stochastic disturbances. The effectiveness of the proposed results is illustrated by two simulation examples. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. 40 Gbit/s NRZ Packet-Length Insensitive Header Extraction for Optical Label Switching Networks

    DEFF Research Database (Denmark)

    Seoane, Jorge; Kehayas, E; Avramopoulos, H.

    2006-01-01

    A simple method for 40 Gbit/s NRZ header extraction based on envelope detection for optical label switching networks is presented. The scheme is insensitive to packet length and spacing and can be single-chip integrated cost-effectively......A simple method for 40 Gbit/s NRZ header extraction based on envelope detection for optical label switching networks is presented. The scheme is insensitive to packet length and spacing and can be single-chip integrated cost-effectively...

  7. Average Consensus Problems in Networks of Agents with Fixed and Switching Topology and Unknown Control Direction

    Directory of Open Access Journals (Sweden)

    Caixian Sun

    2014-01-01

    Full Text Available This paper is devoted to the average consensus problems in directed networks of agents with unknown control direction. In this paper, by using Nussbaum function techniques and Laplacian matrix, novel average consensus protocols are designed for multiagent systems with unknown control direction in the cases of directed networks with fixed and switching topology. In the case of switching topology, the disagreement vector is utilized. Finally, simulation is provided to demonstrate the effectiveness of our results.

  8. Blocking Performance Enhancement Using Congestion Control in Optical Burst Switching Networks

    OpenAIRE

    Pallvi Garg; Naveen Goyal

    2012-01-01

    Issue of congestion in Optical Burst Switching Networks is the main issue now days. Congestion occurs when the reception time is less than transmission time during the transfer of data. In this paper, we had used Modified Erlang’s Loss Formulae to control the congestion in Optical Burst Switching Networks. This control of congestion is done by controlling the blocking probability. The Blocking Probability is related to Traffic Intensity also. Simulation results show that with the value of tr...

  9. A Novel Prototype of Auxiliary Edge Resonant Bridge Leg-Link Snubber-Assisted Soft-Switching Sinewave PWM Inverter

    National Research Council Canada - National Science Library

    Nakamura, Mantaro; Yamazaki, Takayuki; Fujii, Yuma; Ahmed, Tarek; Nakaoka, Mutsuo

    2004-01-01

      This paper proposes a new circuit topology of the three-phase soft switching PWM inverter and PFC converter using IGBT power modules, which has the improved active auxiliary switch and edge resonant...

  10. Silicon photonic switch technology for optical networks in telecom and datacom areas

    Science.gov (United States)

    Nakamura, Shigeru; Yanagimachi, Shigeyuki; Takeshita, Hitoshi; Tajima, Akio

    2017-01-01

    As a promising platform technology for optical switches, silicon photonics is recently attracting much attention. In this paper, we demonstrate compact 8 × 8 silicon photonic switch modules with low loss, low polarization sensitivity, and low cross-talk properties. An optical circuit including 152 thermo-optical switch elements and spot size converters were formed within a silicon chip size of 12 mm × 14 mm. The developed module where a silicon photonic chip was assembled with a fiber array showed about 6-dB average excess optical loss, including optical coupling loss, on all 64 paths of the 8 × 8 optical switch. Measured polarization dependent loss was about 0.6 dB on average over 64 paths and cross-talk was less than -35 dB. These optical switch modules are intended for applying to ROADMs in telecom optical networks, but, the port count extensibility using multiple compact modules and the faster switching capability of the optical switch are also useful for datacenter applications where hybrid network scheme with electronic packet switches and optical circuit switches is intensively investigated.

  11. An Efficient Crosstalk-Free Routing Algorithm Based on Permutation Decomposition for Optical Multi-log2N Switching Networks

    OpenAIRE

    Liu, Xiaofeng; Zhao, Youjian; Wu, Yajuan

    2013-01-01

    Part 3: Session 3: Parallel Architectures; International audience; Optical switching networks (OSN) based on optical directional couplers (DC) may be the most promising candidate to provide a high switching rate when the speed mismatch problem between links (optical fibers) and switches is increasingly serious. Although such switches have many advantages, the DC suffers from an inherent crosstalk problem that can greatly aggravate the switching performance. Based on semi-permutations, a paral...

  12. Feasibility of Optical Packet Switched WDM Networks without Packet Synchronisation Under Bursty Traffic Conditions

    DEFF Research Database (Denmark)

    Fjelde, Tina; Hansen, Peter Bukhave; Kloch, Allan

    1999-01-01

    We show that complex packet synchronisation may be avoided in optical packetswitched networks. Detailed traffic analysis demonstrates that packet lossratios of 1e-10 are feasible under bursty traffic conditions for a highcapacity network consisting of asynchronously operated add-drop switch nodes...

  13. Switched-capacitor sampled-data networks with communication applications

    Science.gov (United States)

    Tu, S.

    1983-01-01

    Synthesis techniques for the realization of switched-capacitor filters (SCF's) as well as oscillators (SCO's) were developed. The proposed techniques are shown to yield realizations which have attractive features in comparison with presently available realizations. Direct synthesis procedures for the switched-capacitor filter is obtained from the transfer function is s-variable. It is shown that, by using the mixed transformation, a second order filter design of better approximation and less frequency warping is obtained. The switched-capacitor oscillators are discussed. A class of oscillation for multiphase sinewave generation is proposed. In the design, a sequence discreminator (SD) is used which provides a set of sinusoids with equally spaced phase angle and equal magnitude. Applying the SC technique to the oscillator design has several advantages in addition to the circuit being suitable for integration.

  14. Quantitative design space exploration of routing-switches for Network-on-Chip

    Directory of Open Access Journals (Sweden)

    M. C. Neuenhahn

    2008-05-01

    Full Text Available Future Systems-on-Chip (SoC will consist of many embedded functional units like e.g. embedded processor cores, memories or FPGA like structures. These SoCs will have huge communication demands, which can not be fulfilled by bus-based communication systems. Possible solutions to this problem are so called Networks-on-Chip (NoC.

    These NoCs basically consist of network-interfaces which integrate functional units into the NoC and routing-switches which connect the network-interfaces. Here, VLSI-based routing-switch implementations are presented. The characteristics of these NoCs like performance and costs (e.g. silicon area respectively logic elements, power dissipation depend on a variety of parameters. As a routing-switch is a key component of a NoC, the costs and performance of routing-switches are compared for different parameter combinations. Evaluated parameters are for example data word length, architecture of the routing-switch (parallel vs. centralized implementation and routing-algorithm.

    The performance and costs of routing-switches were evaluated using an FPGA-based NoC-emulator. In addition different routing-switches were implemented using a 90 nm standard-cell library to determine the maximum clock frequency, power-dissipation and area of a VLSI-implementation. The power consumption was determined by simulating the extracted layout of the routing-switches. Finally, these results are benchmarked to other routing-switch implementations like Aetheral and xpipes.

  15. Average Consensus in Networks of Neutral Dynamical Agents with Fixed and Switching Topologies

    Directory of Open Access Journals (Sweden)

    Yingying Wu

    2015-01-01

    networks with fixed and switching topologies. For the case of fixed topology, necessary and sufficient conditions to average consensus are established by decoupling the neutral multiagent system in terms of the eigenvalues of the Laplacian matrix. For the case of switching topology, sufficient conditions to average consensus are given in terms of linear matrix inequalities to determine the allowable upper bound of the time-varying communication delay. Finally, two examples are worked out to explain the effectiveness of the theoretical results.

  16. An analytical approach to optical burst switched networks

    CERN Document Server

    Venkatesh, T

    2010-01-01

    This book presents the latest results on modeling and analysis of OBS networks. It classifies all the literature on the topic, and its scope extends to include discussion of high-speed communication networks with limited or no buffers.

  17. Energy efficiency benefits of introducing optical switching in Data Center Networks

    DEFF Research Database (Denmark)

    Pilimon, Artur; Zeimpeki, Alexandra; Fagertun, Anna Manolova

    2017-01-01

    In this paper we analyze the impact of WDM-enhanced optical circuit switching on the power consumption of multiple Data Center Network (DCN) architectures. Traditional three-tier Tree, Fat-Tree and a ring-based structure are evaluated and optical switching is selectively introduced on different...... architectures, except the traditional Tree. This is caused by the inability to perform efficient traffic grooming and smaller average nodal degree of this architecture. Enabling optical switching only at the aggregation layer results in the highest energy savings in Fat-Tree and traditional Tree, while...

  18. Adaptive Asymptotical Synchronization for Stochastic Complex Networks with Time-Delay and Markovian Switching

    Directory of Open Access Journals (Sweden)

    Xueling Jiang

    2014-01-01

    Full Text Available The problem of adaptive asymptotical synchronization is discussed for the stochastic complex dynamical networks with time-delay and Markovian switching. By applying the stochastic analysis approach and the M-matrix method for stochastic complex networks, several sufficient conditions to ensure adaptive asymptotical synchronization for stochastic complex networks are derived. Through the adaptive feedback control techniques, some suitable parameters update laws are obtained. Simulation result is provided to substantiate the effectiveness and characteristics of the proposed approach.

  19. Cooperative Adaptive Output Regulation for Second-Order Nonlinear Multiagent Systems With Jointly Connected Switching Networks.

    Science.gov (United States)

    Liu, Wei; Huang, Jie

    2017-01-11

    This paper studies the cooperative global robust output regulation problem for a class of heterogeneous second-order nonlinear uncertain multiagent systems with jointly connected switching networks. The main contributions consist of the following three aspects. First, we generalize the result of the adaptive distributed observer from undirected jointly connected switching networks to directed jointly connected switching networks. Second, by performing a new coordinate and input transformation, we convert our problem into the cooperative global robust stabilization problem of a more complex augmented system via the distributed internal model principle. Third, we solve the stabilization problem by a distributed state feedback control law. Our result is illustrated by the leader-following consensus problem for a group of Van der Pol oscillators.

  20. Cisco Router and Switch Forensics Investigating and Analyzing Malicious Network Activity

    CERN Document Server

    Liu, Dale

    2009-01-01

    Cisco IOS (the software that runs the vast majority of Cisco routers and all Cisco network switches) is the dominant routing platform on the Internet and corporate networks. This widespread distribution, as well as its architectural deficiencies, makes it a valuable target for hackers looking to attack a corporate or private network infrastructure. Compromised devices can disrupt stability, introduce malicious modification, and endanger all communication on the network. For security of the network and investigation of attacks, in-depth analysis and diagnostics are critical, but no book current

  1. Enterasys Networks delivers 10-Gigabit ethernet for the enterprise with new matrix E1 switching family

    CERN Multimedia

    2001-01-01

    Enterasys Networks Inc., today announced its new Matrix E1 family of 10-Gigabit and Gigabit Ethernet switches. The Matrix E1 Optical Access Switch (OAS) enables organizations to deliver applications at 10-Gb speeds across a single fibre optic pair. Jacques Altaber, deputy leader of IT at CERN said "High-bandwith solutions are essential to leveraging more computing power, so 10-Gb Ethernet is the next logical step for us...The Matrix E1 allows us to provide the networking support that our scientists need and gives us a certain future for bandwidth and computing expansion".

  2. High-density, fail-in-place switches for computer and data networks

    Energy Technology Data Exchange (ETDEWEB)

    Coteus, Paul W.; Doany, Fuad E.; Hall, Shawn A.; Schultz, Mark D.; Takken, Todd E.; Tian, Shurong

    2017-04-25

    A structure for a network switch. The network switch may include a plurality of spine chips arranged on a plurality of spine cards, where one or more spine chips are located on each spine card; and a plurality of leaf chips arranged on a plurality of leaf cards, wherein one or more leaf chips are located on each leaf card, where each spine card is connected to every leaf chip and the plurality of spine chips are surrounded on at least two sides by leaf cards.

  3. Attractor and Boundedness of Switched Stochastic Cohen-Grossberg Neural Networks

    Directory of Open Access Journals (Sweden)

    Chuangxia Huang

    2016-01-01

    Full Text Available We address the problem of stochastic attractor and boundedness of a class of switched Cohen-Grossberg neural networks (CGNN with discrete and infinitely distributed delays. With the help of stochastic analysis technology, the Lyapunov-Krasovskii functional method, linear matrix inequalities technique (LMI, and the average dwell time approach (ADT, some novel sufficient conditions regarding the issues of mean-square uniformly ultimate boundedness, the existence of a stochastic attractor, and the mean-square exponential stability for the switched Cohen-Grossberg neural networks are established. Finally, illustrative examples and their simulations are provided to illustrate the effectiveness of the proposed results.

  4. Finite time control of uncertain networked switched linear systems with quantizations

    Science.gov (United States)

    Chen, Xiaoling; Zhou, Guopeng; Tian, Fengxia; Liu, Hao

    2017-01-01

    This paper is concerned with the finite-time control problem for uncertain networked switched linear systems with both state and control input quantizations. By employing average well dwell time (ADT) and Lyapunov-like function method, a feedback controller is designed to guarantee that the dynamic augment closed-loop system is finite-time boundedness. Then based on this, some sufficient conditions which ensure the finite-time boundedness of networked switched systems are derived in terms of linear matrix inequalities. Finally, a numerical example is given to illustrate the effectiveness of the proposed design approach.

  5. Multi-granularity grooming using timing information in optical networks with waveband and TDM switching

    OpenAIRE

    Tabarak allah Ali Mohamed; Salwa El-Sabban; Gamal Abdel Fadeel Mohamed Khalaf

    2014-01-01

    In this paper, we incorporate the idea of waveband switching in Mixed Line Rates (MLR) network design to address the problem of dynamic traffic grooming in waveband switching networks by investigating a cost function which take the effect of call holding time on the time slot assignment process of in WDM–TDM. Use has been made of Markov model in order to predict the wavelength congestion. A routing algorithm is developed based on the Markov modeling. The results are compared with existing rou...

  6. Photonics-oriented data transmission network for the KM3NeT prototype detector

    Energy Technology Data Exchange (ETDEWEB)

    Hoek, M. van der; Mos, S.; Schmelling, J.W.; Hogenbirk, J.; Heine, E.; Jansweijer, P.; Kieft, G.; Peek, H.; Timmer, P. [Nikhef, Science Park 105, 1098 XG Amsterdam (Netherlands); Wolf, E. de, E-mail: e.dewolf@nikhef.nl [Nikhef, Science Park 105, 1098 XG Amsterdam (Netherlands); University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Zwart, A. [Nikhef, Science Park 105, 1098 XG Amsterdam (Netherlands)

    2013-10-11

    The design of the readout and data acquisition system of the future KM3NeT neutrino telescope employs 10 Gbps photonic technologies for data transmission to shore. The photonic architecture can handle standard transmission protocols. The generic scheme is based on DWDM technology using lasers on shore and optical modulators in each of the 12,800 Digital Optical Modules arranged on several hundred vertical detection units anchored to the seabed. Each module will house 31 photomultipliers together with auxiliary instrumentation and readout electronics. A 100 km electro-optical fibre cable will connect the optical modules to the store. The readout system will guarantee an individual optical connection between each optical module and the shore. A small-scale prototype of a detection unit with four optical modules is in a realization phase and will allow for in situ testing of the data transmission network. We will present results of laboratory tests of the photonics-oriented transmission layer of the network that have been realized for the prototype detection unit.

  7. Flexible-rate optical packet generation/detection and label swapping for optical label switching networks

    Science.gov (United States)

    Wu, Zhongying; Li, Juhao; Tian, Yu; Ge, Dawei; Zhu, Paikun; Chen, Yuanxiang; Chen, Zhangyuan; He, Yongqi

    2017-03-01

    In recent years, optical label switching (OLS) gains lots of attentions due to its intrinsic advantages to implement protocol, bit-rate, granularity and data format transparency packet switching. In this paper, we propose a novel scheme to realize flexible-rate optical packet switching for OLS networks. At the transmitter node, flexible-rate packet is generated by parallel modulating different combinations of optical carriers generated from the optical multi-carrier generator (OMCG), among which the low-speed optical label occupies one carrier. At the switching node, label is extracted and re-generated in label processing unit (LPU). The payloads are switched based on routing information and new label is added after switching. At the receiver node, another OMCG serves as local oscillators (LOs) for optical payloads coherent detection. The proposed scheme offers good flexibility for dynamic optical packet switching by adjusting the payload bandwidth and could also effectively reduce the number of lasers, modulators and receivers for packet generation/detection. We present proof-of-concept demonstrations of flexible-rate packet generation/detection and label swapping in 12.5 GHz grid. The influence of crosstalk for cascaded label swapping is also investigated.

  8. On-Chip SDM Switching for Unicast, Multicast and Traffic Grooming in Data Center Networks

    DEFF Research Database (Denmark)

    Kamchevska, Valerija; Ding, Yunhong; Dalgaard, Kjeld

    2017-01-01

    This paper reports on the use of a novel photonic integrated circuit that facilitates multicast and grooming in an optical data center architecture. The circuit allows for on-chip spatial multiplexing and demultiplexing as well as fiber core switching. Using this device, we experimentally verify...... that multicast and/or grooming can be successfully performed along the full range of output ports, for different group size and different power ratio. Moreover, we experimentally demonstrate SDM transmission and 5 Tbit/s switching using the on-chip fiber switch with integrated fan-in/fan-out devices and achieve...... errorfree performance (BER≤10-9) for a network scenario including simultaneous unicast/multicast switching and traffic grooming....

  9. Design of a Reliable Wireless Switch for the Intersection Area on Vehicular Telematics Networks

    Science.gov (United States)

    Lee, Junghoon; Park, Gyung-Leen; Kwak, Ho-Young; Lee, Sang Joon; Kang, Mikyung

    This paper proposes an efficient message switch scheme for an intersection area in vehicular telematics network, where routing decision may be complex due to dynamic vehicle distribution change. Installed at each corner of an intersection, each switch node opens an external interface to exchange messages with vehicles proceeding to the intersection from the pre-assigned branch, while switching the received messages via the internal interfaces, accessing two shared channels according to slot-based MAC. The difference in the access phases across two channels further enhances the switch speed and message discard ratio. The performance measurement result obtained by simulation using SMPL shows that the proposed scheme can improve the access delay by up to 16.4 %, showing over 85 % delivery ratio for all discard interval range.

  10. Protection switching schemes of multi-granularity p-cycles in survivable WDM networks

    Science.gov (United States)

    Zhu, Guolong; Zeng, Qingji; Ye, Tong; Yang, Junjie

    2004-09-01

    In this paper, a novel concept of multi-granularity p-cycle is proposed. In conventional p-cycle concept, all on-cycle spans have the same capacity. However, in multi-granularity p-cycle, each on-cycle span could have different capacity. Results show that multi-granularity p-cycles are much more capacity-efficient and cost-effective than conventional p-cycles. We also propose two protection switching schemes for all types of p-cycle networks. One is wrapping protection, in which only two end nodes do real-time switching when a span failure happens. The other is steering protection, in which at most four nodes do real-time switching when a span fails. In steering protection switching scheme, the restoration path for the failure traffic demand has the least hops.

  11. Dual branch transmit switch-and-stay diversity for underlay cognitive networks

    KAUST Repository

    Sayed, Mostafa M.

    2011-05-01

    In this paper, we study applying dual branch transmit switch-and-stay combining (SSC) technique for underlay cognitive radio (UCR) networks. In UCR, the secondary user is allowed to share the spectrum with the primary (licensed) user under the condition that interference at the primary receiver is below a predetermined threshold. Assuming binary phaseshift keying (BPSK) modulation and Rayleigh fading channels, we develop a closed form expression for the average bit error rate (BER) of the secondary link as a function of the switching threshold. We then find a closed form expression for the optimal switching threshold in the sense of minimizing the average BER. For the sake of comparison we derive an expression for the average BER of the dual branch transmit selection combining (SC) technique. We finally investigate the effect of correlation between secondary and interference channels on the average BER and the associated optimal switching threshold. © 2011 IEEE.

  12. Optical Switching for Dynamic Distribution of Wireless-Over-Fiber Signals in Active Optical Networks

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Rodes, Guillermo; Tafur Monroy, Idelfonso

    2012-01-01

    In this paper, we report on an experimental validation of dynamic distribution of wireless-over-fiber by employing optical switching using semiconductor optical amplifiers; we also provide a channel distribution scheme and a generic topology for such an optical switch. The experiment consists...... of a four wavelength-division-multiplexed channel system operating on a WiMax frequency band and employing an orthogonal-frequency-division-multiplexing modulation at 625 Mbits/s per channel, transmission of the data over 20 km of optical fiber, and active switching in a 1 × 16 active optical switch....... The results show a negligible power penalty on each channel for both the best and the worst case in terms of inter-channel crosstalk. The presented system is highly scalable both in terms of port count and throughput, a desirable feature in highly branched access networks, and is modulation- and frequency...

  13. Traffic characteristics analysis in optical burst switching networks with optical label processing

    Directory of Open Access Journals (Sweden)

    Edson Moschim

    2007-03-01

    Full Text Available An analysis is carried out with burst-switching optical networks which use label processing consisting of orthogonal optical codes (OOC, considering traffic characteristics such as length/duration and arrival rate of bursts. Main results show that the use of OOC label processing influences on the decrease of burst loss probability, especially for short-lived bursts. Therefore, short bursts that would be blocked in conventional electronic processing networks are transmitted when the OOC label processing is used. Thus, an increase in the network use occurs as well as a decrease in the burst transmission latency, reaching a granularity close to packets networks.

  14. Implementing a prototyping network for injection moulded imaging lenses in Finland

    Science.gov (United States)

    Keränen, K.; Mäkinen, J.-T.; Pääkkönen, E. J.; Koponen, M.; Karttunen, M.; Hiltunen, J.; Karioja, P.

    2005-10-01

    A network for prototyping imaging lenses using injection moulding was established in Finland. The network consists of several academic and industrial partners capable of designing, processing and characterising imaging lenses produced by injection moulding technology. In order to validate the operation of the network a demonstrator lens was produced. The process steps included in the manufacturing were lens specification, designing and modelling, material selection, mould tooling, moulding process simulation, injection moulding and characterisation. A magnifying imaging singlet lens to be used as an add-on in a camera phone was selected as a demonstrator. The design of the add-on lens proved to be somewhat challenging, but a double aspheric singlet lens design fulfilling nearly the requirement specification was produced. In the material selection task the overall characteristics profile of polymethyl methacrylate (PMMA) material was seen to be the most fitting to the pilot case. It is a low cost material with good moulding properties and therefore it was selected as a material for the pilot lens. Lens mould design was performed using I-DEAS and tested by using MoldFlow 3D injection moulding simulation software. The simulations predicted the achievable lens quality in the processing, when using a two-cavity mould design. First cavity was tooled directly into the mould plate and the second cavity was made by tooling separate insert pieces for the mould. Mould material was steel and the inserts were made from Moldmax copper alloy. Parts were tooled with high speed milling machines. Insert pieces were hand polished after tooling. Prototype lenses were injection moulded using two PMMA grades, namely 6N and 7N. Different process parameters were also experimented in the injection moulding test runs. Prototypes were characterised by measuring mechanical dimensions, surface profile, roughness and MTF of the lenses. Characterisations showed that the lens surface RMS

  15. A Fully Implemented 12 × 12 Data Vortex Optical Packet Switching Interconnection Network

    Science.gov (United States)

    Shacham, Assaf; Small, Benjamin A.; Liboiron-Ladouceur, Odile; Bergman, Keren

    2005-10-01

    A fully functional optical packet switching (OPS) interconnection network based on the data vortex architecture is presented. The photonic switching fabric uniquely capitalizes on the enormous bandwidth advantage of wavelength division multiplexing (WDM) wavelength parallelism while delivering minimal packet transit latency. Utilizing semiconductor optical amplifier (SOA)-based switching nodes and conventional fiber-optic technology, the 12-port system exhibits a capacity of nearly 1 Tb/s. Optical packets containing an eight-wavelength WDM payload with 10 Gb/s per wavelength are routed successfully to all 12 ports while maintaining a bit error rate (BER) of 10-12 or better. Median port-to-port latencies of 110 ns are achieved with a distributed deflection routing network that resolves packet contention on-the-fly without the use of optical buffers and maintains the entire payload path in the optical domain.

  16. Simulation and stability analysis of neural network based control scheme for switched linear systems.

    Science.gov (United States)

    Singh, H P; Sukavanam, N

    2012-01-01

    This paper proposes a new adaptive neural network based control scheme for switched linear systems with parametric uncertainty and external disturbance. A key feature of this scheme is that the prior information of the possible upper bound of the uncertainty is not required. A feedforward neural network is employed to learn this upper bound. The adaptive learning algorithm is derived from Lyapunov stability analysis so that the system response under arbitrary switching laws is guaranteed uniformly ultimately bounded. A comparative simulation study with robust controller given in [Zhang L, Lu Y, Chen Y, Mastorakis NE. Robust uniformly ultimate boundedness control for uncertain switched linear systems. Computers and Mathematics with Applications 2008; 56: 1709-14] is presented. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  17. A Scheme to Optimize Flow Routing and Polling Switch Selection of Software Defined Networks

    Science.gov (United States)

    Chen, Huan; Li, Lemin; Ren, Jing; Wang, Yang; Zhao, Yangming; Wang, Xiong; Wang, Sheng; Xu, Shizhong

    2015-01-01

    This paper aims at minimizing the communication cost for collecting flow information in Software Defined Networks (SDN). Since flow-based information collecting method requires too much communication cost, and switch-based method proposed recently cannot benefit from controlling flow routing, jointly optimize flow routing and polling switch selection is proposed to reduce the communication cost. To this end, joint optimization problem is formulated as an Integer Linear Programming (ILP) model firstly. Since the ILP model is intractable in large size network, we also design an optimal algorithm for the multi-rooted tree topology and an efficient heuristic algorithm for general topology. According to extensive simulations, it is found that our method can save up to 55.76% communication cost compared with the state-of-the-art switch-based scheme. PMID:26690571

  18. A Scheme to Optimize Flow Routing and Polling Switch Selection of Software Defined Networks.

    Directory of Open Access Journals (Sweden)

    Huan Chen

    Full Text Available This paper aims at minimizing the communication cost for collecting flow information in Software Defined Networks (SDN. Since flow-based information collecting method requires too much communication cost, and switch-based method proposed recently cannot benefit from controlling flow routing, jointly optimize flow routing and polling switch selection is proposed to reduce the communication cost. To this end, joint optimization problem is formulated as an Integer Linear Programming (ILP model firstly. Since the ILP model is intractable in large size network, we also design an optimal algorithm for the multi-rooted tree topology and an efficient heuristic algorithm for general topology. According to extensive simulations, it is found that our method can save up to 55.76% communication cost compared with the state-of-the-art switch-based scheme.

  19. Reconstruction of switching thresholds in piecewise-affine models of genetic regulatory networks

    OpenAIRE

    Drulhe, Samuel; Ferrari-Trecate, Giancarlo; De Jong, Hidde; Viari, Alain

    2006-01-01

    http://dx.doi.org/10.1007/11730637_16; Recent advances of experimental techniques in biology have led to the production of enormous amounts of data on the dynamics of genetic regulatory networks. In this paper, we present an approach for the identification of PieceWise-Affine (PWA) models of genetic regulatory networks from experimental data, focusing on the reconstruction of switching thresholds associated with regulatory interactions. In particular, our method takes into account geometric c...

  20. The rearrangement process in a two-stage broadcast switching network

    DEFF Research Database (Denmark)

    Jacobsen, Søren B.

    1988-01-01

    The rearrangement process in the two-stage broadcast switching network presented by F.K. Hwang and G.W. Richards (ibid., vol.COM-33, no.10, p.1025-1035, Oct. 1985) is considered. By defining a certain function it is possible to calculate an upper bound on the number of connections to be moved...

  1. On the Highly Stable Performance of Loss-Free Optical Burst Switching Networks

    Directory of Open Access Journals (Sweden)

    Milos Kozak

    2016-01-01

    Full Text Available Increase of bandwidth demand in data networks, driven by the continuous growth of the Internet and the increase of bandwidth greedy applications, raise the issue of how to support all the bandwidth requirements in the near future. Three optical switching paradigms have been defined and are being investigated: Optical Circuit Switching (OCS; Optical Packet Switching (OPS; and Optical Burst Switching (OBS. Among these paradigms, OBS is seen as the most appropriate solution today. However, OBS suffers from high burst loss as a result of contention in the bufferless mode of operation. This issue was investigated by Coutelen et al., 2009 who proposed the loss-free CAROBS framework whereby signal convertors of the optical signal to the electrical domain ensure electrical buffering. Convertors increase the network price which must be minimized to reduce the installation and operating costs of the CAROBS framework. An analysis capturing convertor requirements, with respect to the number of merging flows and CAROBS node offered load, was carried out. We demonstrated the convertor location significance, which led to an additional investigation of the shared wavelength convertors scenario. Shared wavelength convertors significantly decrease the number of required convertors and show great promise for CAROBS. Based on this study we can design a CAROBS network to contain a combination of simple and complex nodes that include none or some convertors respectively, a vital feature of network throughput efficiency and cost.

  2. Attractor switching in neuron networks and Spatiotemporal filters for motion processing

    NARCIS (Netherlands)

    Subramanian, Easwara Naga

    2008-01-01

    From a broader perspective, we address two important questions, viz., (a) what kind of mechanism would enable a neuronal network to switch between various tasks or stored patterns? (b) what are the properties of neurons that are used by the visual system in early motion detection? To address (a) we

  3. Argonne National Lab deploys Force10 networks' massively dense ethernet switch for supercomputing cluster

    CERN Multimedia

    2003-01-01

    "Force10 Networks, Inc. today announced that Argonne National Laboratory (Argonne, IL) has successfully deployed Force10 E-Series switch/routers to connect to the TeraGrid, the world's largest supercomputing grid, sponsored by the National Science Foundation (NSF)" (1/2 page).

  4. PEDSnet: how a prototype pediatric learning health system is being expanded into a national network.

    Science.gov (United States)

    Forrest, Christopher B; Margolis, Peter; Seid, Michael; Colletti, Richard B

    2014-07-01

    Except for a few conditions, pediatric disorders are rare diseases. Because of this, no single institution has enough patients to generate adequate sample sizes to produce generalizable knowledge. Aggregating electronic clinical data from millions of children across many pediatric institutions holds the promise of producing sufficiently large data sets to accelerate knowledge discovery. However, without deliberately embedding these data in a pediatric learning health system (defined as a health care organization that is purposefully designed to produce research in routine care settings and implement evidence at the point of care), efforts to act on this new knowledge, reducing the distress and suffering that children experience when sick, will be ineffective. In this article we discuss a prototype pediatric learning health system, ImproveCareNow, for children with inflammatory bowel disease. This prototype is being scaled up to create PEDSnet, a national network that will support the efficient conduct of clinical trials, observational research, and quality improvement across diseases, specialties, and institutions. Project HOPE—The People-to-People Health Foundation, Inc.

  5. The Drosophila gap gene network is composed of two parallel toggle switches.

    Directory of Open Access Journals (Sweden)

    Dmitri Papatsenko

    Full Text Available Drosophila "gap" genes provide the first response to maternal gradients in the early fly embryo. Gap genes are expressed in a series of broad bands across the embryo during first hours of development. The gene network controlling the gap gene expression patterns includes inputs from maternal gradients and mutual repression between the gap genes themselves. In this study we propose a modular design for the gap gene network, involving two relatively independent network domains. The core of each network domain includes a toggle switch corresponding to a pair of mutually repressive gap genes, operated in space by maternal inputs. The toggle switches present in the gap network are evocative of the phage lambda switch, but they are operated positionally (in space by the maternal gradients, so the synthesis rates for the competing components change along the embryo anterior-posterior axis. Dynamic model, constructed based on the proposed principle, with elements of fractional site occupancy, required 5-7 parameters to fit quantitative spatial expression data for gap gradients. The identified model solutions (parameter combinations reproduced major dynamic features of the gap gradient system and explained gap expression in a variety of segmentation mutants.

  6. Multi-granularity grooming using timing information in optical networks with waveband and TDM switching

    Directory of Open Access Journals (Sweden)

    Tabarak allah Ali Mohamed

    2014-06-01

    Full Text Available In this paper, we incorporate the idea of waveband switching in Mixed Line Rates (MLR network design to address the problem of dynamic traffic grooming in waveband switching networks by investigating a cost function which take the effect of call holding time on the time slot assignment process of in WDM–TDM. Use has been made of Markov model in order to predict the wavelength congestion. A routing algorithm is developed based on the Markov modeling. The results are compared with existing routing algorithms – Available Shortest Path (ASP and Online Traffic Grooming Algorithm (OTGA. Validation results have shown that the performance of the proposed system is significantly improved in terms of bandwidth blocking ratio, network utilization as well as port saving due to wavebanding.

  7. Pathway switching explains the sharp response characteristic of hypoxia response network.

    Directory of Open Access Journals (Sweden)

    Yihai Yu

    2007-08-01

    Full Text Available Hypoxia induces the expression of genes that alter metabolism through the hypoxia-inducible factor (HIF. A theoretical model based on differential equations of the hypoxia response network has been previously proposed in which a sharp response to changes in oxygen concentration was observed but not quantitatively explained. That model consisted of reactions involving 23 molecular species among which the concentrations of HIF and oxygen were linked through a complex set of reactions. In this paper, we analyze this previous model using a combination of mathematical tools to draw out the key components of the network and explain quantitatively how they contribute to the sharp oxygen response. We find that the switch-like behavior is due to pathway-switching wherein HIF degrades rapidly under normoxia in one pathway, while the other pathway accumulates HIF to trigger downstream genes under hypoxia. The analytic technique is potentially useful in studying larger biomedical networks.

  8. Fuzzy-Based Adaptive Hybrid Burst Assembly Technique for Optical Burst Switched Networks

    Directory of Open Access Journals (Sweden)

    Abubakar Muhammad Umaru

    2014-01-01

    Full Text Available The optical burst switching (OBS paradigm is perceived as an intermediate switching technology for future all-optical networks. Burst assembly that is the first process in OBS is the focus of this paper. In this paper, an intelligent hybrid burst assembly algorithm that is based on fuzzy logic is proposed. The new algorithm is evaluated against the traditional hybrid burst assembly algorithm and the fuzzy adaptive threshold (FAT burst assembly algorithm via simulation. Simulation results show that the proposed algorithm outperforms the hybrid and the FAT algorithms in terms of burst end-to-end delay, packet end-to-end delay, and packet loss ratio.

  9. Methods and Results for a Global Precipitation Measurement (GPM) Validation Network Prototype

    Science.gov (United States)

    Morris, Kenneth R.; Schwaller, Mathew R.

    2010-01-01

    As one component of a ground validation system to meet requirements for the upcoming Global Precipitation Measurement (GPM) mission, a quasi-operational prototype a system to compare satellite- and ground-based radar measurements has been developed. This prototype, the GPM Validation Network (VN), acquires data from the Precipitation Radar (PR) on the Tropical Rainfall Measuring Mission (TRMM) satellite and from ground radar (GR) networks in the continental U.S. and participating international sites. PR data serve as a surrogate for similar observations from the Dual-frequency Precipitation Radar (DPR) to be present on GPM. Primary goals of the VN prototype are to understand and characterize the variability and bias of precipitation retrievals between the PR and GR in various precipitation regimes at large scales, and to improve precipitation retrieval algorithms for the GPM instruments. The current VN capabilities concentrate on comparisons of the base reflectivity observations between the PR and GR, and include support for rain rate comparisons. The VN algorithm resamples PR and GR reflectivity and other 2-D and 3-D data fields to irregular common volumes defined by the geometric intersection of the instrument observations, and performs statistical comparisons of PR and GR reflectivity and estimated rain rates. Algorithmic biases and uncertainties introduced by traditional data analysis techniques are minimized by not performing interpolation or extrapolation of data to a fixed grid. The core VN dataset consists of WSR-88D GR data and matching PR orbit subset data covering 21 sites in the southeastern U. S., from August, 2006 to the present. On average, about 3.5 overpass events per month for these WSR-88D sites meet VN criteria for significant precipitation, and have matching PR and GR data available. This large statistical sample has allowed the relative calibration accuracy and stability of the individual ground radars, and the quality of the PR reflectivity

  10. Improvements in Routing for Packet-Switched Networks

    Science.gov (United States)

    1975-02-18

    LINK NETWORK WITH NO DESTRUCTION 106 1- NU 2. BL 3. Nk 4. SP 5. BA 6. NU, LNV. BTL 7. NU, L3NV, BTL 8. NU. LSNV , BTL 9. FL, LNV, BTL 10. BL...L3NV, BTL 11. BL, LSNV . BTL 12. NU, LNV, BTL, lOvT aging 13. NU, LNV, BTL, 50% aging 14. NU. LNV, BTL, 75% agwg 15. BL, LNV, BTL, 10% aging 16...NU, LNV. BTL 8. NU. L3NV. BTL 9. NU. LSNV , BTL 10. BL. LNV, BTL n. BL, L3NV, BTL 12. BL, LSNV , BTL 13. BA, LNV, BTL 14. BA, L3NV, BTL 15. BA

  11. On-chip switch for reconfigurable mode-multiplexing optical network.

    Science.gov (United States)

    Sun, Chunlei; Yu, Yu; Chen, Guanyu; Zhang, Xinliang

    2016-09-19

    The switching and routing is essential for an advanced and reconfigurable optical network, and great efforts have been done for traditional single-mode system. We propose and demonstrate an on-chip switch compatible with mode-division multiplexing system. By controlling the induced phase difference, the functionalities of dynamically routing data channels can be achieved. The proposed switch is experimentally demonstrated with low insertion loss of ~1 dB and high extinction ratio of ~20 dB over the C-band for OFF-ON switchover. For further demonstration, the non-return-to-zero on-off keying signals at 10 Gb/s carried on the two spatial modes are successfully processed. Open and clear eye diagrams can be observed and the bit error rate measurements indicate a good data routing performance.

  12. Landslide and Flood Warning System Prototypes based on Wireless Sensor Networks

    Science.gov (United States)

    Hloupis, George; Stavrakas, Ilias; Triantis, Dimos

    2010-05-01

    Wireless sensor networks (WSNs) are one of the emerging areas that received great attention during the last few years. This is mainly due to the fact that WSNs have provided scientists with the capability of developing real-time monitoring systems equipped with sensors based on Micro-Electro-Mechanical Systems (MEMS). WSNs have great potential for many applications in environmental monitoring since the sensor nodes that comprised from can host several MEMS sensors (such as temperature, humidity, inertial, pressure, strain-gauge) and transducers (such as position, velocity, acceleration, vibration). The resulting devices are small and inexpensive but with limited memory and computing resources. Each sensor node contains a sensing module which along with an RF transceiver. The communication is broadcast-based since the network topology can change rapidly due to node failures [1]. Sensor nodes can transmit their measurements to central servers through gateway nodes without any processing or they make preliminary calculations locally in order to produce results that will be sent to central servers [2]. Based on the above characteristics, two prototypes using WSNs are presented in this paper: A Landslide detection system and a Flood warning system. Both systems sent their data to central processing server where the core of processing routines exists. Transmission is made using Zigbee and IEEE 802.11b protocol but is capable to use VSAT communication also. Landslide detection system uses structured network topology. Each measuring node comprises of a columnar module that is half buried to the area under investigation. Each sensing module contains a geophone, an inclinometer and a set of strain gauges. Data transmitted to central processing server where possible landslide evolution is monitored. Flood detection system uses unstructured network topology since the failure rate of sensor nodes is expected higher. Each sensing module contains a custom water level sensor

  13. Testing and Modeling Ethernet Switches and Networks for Use in ATLAS High-level Triggers

    CERN Document Server

    Dobinson, Robert W; Korcyl, K; Le Vine, M J; Lokier, J; Martin, B; Meirosu, C; Saka, F; Vella, K

    2001-01-01

    The ATLAS second level trigger will use a multi-layered LAN network to transfer 5 Gbyte/s detector data from ~1500 buffers to a few hundred processors. A model of the network has been constructed to evaluate its performance. A key component of the network model is a model of an individual switch, reproducing the behavior measured in real devices. A small number of measurable parameters are used to model a variety of commercial Ethernet switches. Using parameters measured on real devices, the impact on the overall network performance is modeled. In the Atlas context, both 100 Mbit and Gigabit Ethernet links are required. A system is described which is capable of characterizing the behavior of commercial switches with the required number of nodes under traffic conditions resembling those to be encountered in the Atlas experiment. Fast Ethernet traffic is provided by a high density, custom built tester based on FPGAs, programmed in Handel-C and VHDL, while the Gigabit Ethernet traffic is generated using Alteon N...

  14. A neural network model of individual differences in task switching abilities.

    Science.gov (United States)

    Herd, Seth A; O'Reilly, Randall C; Hazy, Tom E; Chatham, Christopher H; Brant, Angela M; Friedman, Naomi P

    2014-09-01

    We use a biologically grounded neural network model to investigate the brain mechanisms underlying individual differences specific to the selection and instantiation of representations that exert cognitive control in task switching. Existing computational models of task switching do not focus on individual differences and so cannot explain why task switching abilities are separable from other executive function (EF) abilities (such as response inhibition). We explore hypotheses regarding neural mechanisms underlying the "Shifting-Specific" and "Common EF" components of EF proposed in the Unity/Diversity model (Miyake & Friedman, 2012) and similar components in related theoretical frameworks. We do so by adapting a well-developed neural network model of working memory (Prefrontal cortex, Basal ganglia Working Memory or PBWM; Hazy, Frank, & O'Reilly, 2007) to task switching and the Stroop task, and comparing its behavior on those tasks under a variety of individual difference manipulations. Results are consistent with the hypotheses that variation specific to task switching (i.e., Shifting-Specific) may be related to uncontrolled, automatic persistence of goal representations, whereas variation general to multiple EFs (i.e., Common EF) may be related to the strength of PFC representations and their effect on processing in the remainder of the cognitive system. Moreover, increasing signal to noise ratio in PFC, theoretically tied to levels of tonic dopamine and a genetic polymorphism in the COMT gene, reduced Stroop interference but increased switch costs. This stability-flexibility tradeoff provides an explanation for why these two EF components sometimes show opposing correlations with other variables such as attention problems and self-restraint. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. IP-oriented control of unidirectional-path-switched-ring-based transport networks

    Science.gov (United States)

    Sharma, Vishal; Das, Abhimanyu; Chen, Charles

    2003-03-01

    An important requirement in the IP-based control of time-division multiplexing (TDM) optical transport networks is to utilize the in-built protection capabilities of synchronous optical network (SONET) unidirectional path-switched rings (UPSRs) and to automate the UPSR-protected path setup in mixed mesh-ring networks. This requires modifications to existing IP signaling and routing protocols and new processing rules at the network nodes. Here we leverage IP routing and signaling and multiprotocol label switching (MPLS) fast-reroute techniques for accurately advertising UPSR ring topologies to remote nodes and dynamically establishing UPSR-protected paths across a transport network. Our proposal also makes a NUT1-like (nonpreemptible unprotected traffic) feature possible in UPSRs, which allows for efficient utilization of UPSR protection bandwidth. We achieve this by encoding UPSR-specific information in the open shortest-path-first (OSPF) link state advertisements and in signaling messages of the Resource Reservation Protocol (RSVP) with TE extensions. In addition, we modify the signaling and routing state machines at the nodes to interpret and process this information to perform UPSR topology discovery and path computation. The uniqueness of our proposals is that the algorithms and the rules specified here allow for existing IP-based protocols [such as those within the generalized MPLS (GMPLS) framework, which currently applies to mesh networks] to be efficiently adapted for this context while still achieving our objective of exploiting UPSR-protection capabilities.

  16. Dynamic rewiring of the Drosophila retinal determination network switches its function from selector to differentiation.

    Directory of Open Access Journals (Sweden)

    Mardelle Atkins

    2013-08-01

    Full Text Available Organ development is directed by selector gene networks. Eye development in the fruit fly Drosophila melanogaster is driven by the highly conserved selector gene network referred to as the "retinal determination gene network," composed of approximately 20 factors, whose core comprises twin of eyeless (toy, eyeless (ey, sine oculis (so, dachshund (dac, and eyes absent (eya. These genes encode transcriptional regulators that are each necessary for normal eye development, and sufficient to direct ectopic eye development when misexpressed. While it is well documented that the downstream genes so, eya, and dac are necessary not only during early growth and determination stages but also during the differentiation phase of retinal development, it remains unknown how the retinal determination gene network terminates its functions in determination and begins to promote differentiation. Here, we identify a switch in the regulation of ey by the downstream retinal determination genes, which is essential for the transition from determination to differentiation. We found that central to the transition is a switch from positive regulation of ey transcription to negative regulation and that both types of regulation require so. Our results suggest a model in which the retinal determination gene network is rewired to end the growth and determination stage of eye development and trigger terminal differentiation. We conclude that changes in the regulatory relationships among members of the retinal determination gene network are a driving force for key transitions in retinal development.

  17. A Time-Varied Probabilistic ON/OFF Switching Algorithm for Cellular Networks

    KAUST Repository

    Rached, Nadhir B.

    2018-01-11

    In this letter, we develop a time-varied probabilistic on/off switching planning method for cellular networks to reduce their energy consumption. It consists in a risk-aware optimization approach that takes into consideration the randomness of the user profile associated with each base station (BS). The proposed approach jointly determines (i) the instants of time at which the current active BS configuration must be updated due to an increase or decrease of the network traffic load, and (ii) the set of minimum BSs to be activated to serve the networks’ subscribers. Probabilistic metrics modeling the traffic profile variation are developed to trigger this dynamic on/off switching operation. Selected simulation results are then performed to validate the proposed algorithm for different system parameters.

  18. Stability analysis of switched cellular neural networks: A mode-dependent average dwell time approach.

    Science.gov (United States)

    Huang, Chuangxia; Cao, Jie; Cao, Jinde

    2016-10-01

    This paper addresses the exponential stability of switched cellular neural networks by using the mode-dependent average dwell time (MDADT) approach. This method is quite different from the traditional average dwell time (ADT) method in permitting each subsystem to have its own average dwell time. Detailed investigations have been carried out for two cases. One is that all subsystems are stable and the other is that stable subsystems coexist with unstable subsystems. By employing Lyapunov functionals, linear matrix inequalities (LMIs), Jessen-type inequality, Wirtinger-based inequality, reciprocally convex approach, we derived some novel and less conservative conditions on exponential stability of the networks. Comparing to ADT, the proposed MDADT show that the minimal dwell time of each subsystem is smaller and the switched system stabilizes faster. The obtained results extend and improve some existing ones. Moreover, the validness and effectiveness of these results are demonstrated through numerical simulations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Observer design for switched recurrent neural networks: an average dwell time approach.

    Science.gov (United States)

    Lian, Jie; Feng, Zhi; Shi, Peng

    2011-10-01

    This paper is concerned with the problem of observer design for switched recurrent neural networks with time-varying delay. The attention is focused on designing the full-order observers that guarantee the global exponential stability of the error dynamic system. Based on the average dwell time approach and the free-weighting matrix technique, delay-dependent sufficient conditions are developed for the solvability of such problem and formulated as linear matrix inequalities. The error-state decay estimate is also given. Then, the stability analysis problem for the switched recurrent neural networks can be covered as a special case of our results. Finally, four illustrative examples are provided to demonstrate the effectiveness and the superiority of the proposed methods. © 2011 IEEE

  20. The Strict-Sense Nonblocking Multirate logd(N,0,p Switching Network

    Directory of Open Access Journals (Sweden)

    Wojciech Kabaciński

    2017-01-01

    Full Text Available This paper considers the nonblocking conditions for a multirate logd(N,0,p switching network at the connection level. The necessary and sufficient conditions for the discrete bandwidth model, as well as sufficient and, in particular cases, also necessary conditions for the continuous bandwidth model, were given. The results given for dn-1/2f0≥f1+1 in the discrete bandwidth model are the same as those proposed by Hwang et al. (2005; however, in this paper, these results were extended to other values of f0, f1, and d. In the continuous bandwidth model for B+b>1, the results given in this paper are also the same as those by Hwang et al. (2005; however, for B+b≤1, it was proved that a smaller number of vertically stacked logdN switching networks are needed.

  1. Stability Analysis of Recurrent Neural Networks with Random Delay and Markovian Switching

    Directory of Open Access Journals (Sweden)

    Enwen Zhu

    2010-01-01

    Full Text Available In this paper, the exponential stability analysis problem is considered for a class of recurrent neural networks (RNNs with random delay and Markovian switching. The evolution of the delay is modeled by a continuous-time homogeneous Markov process with a finite number of states. The main purpose of this paper is to establish easily verifiable conditions under which the random delayed recurrent neural network with Markovian switching is exponentially stable. The analysis is based on the Lyapunov-Krasovskii functional and stochastic analysis approach, and the conditions are expressed in terms of linear matrix inequalities, which can be readily checked by using some standard numerical packages such as the Matlab LMI Toolbox. A numerical example is exploited to show the usefulness of the derived LMI-based stability conditions.

  2. Switching behavior of droplets crossing nodes on a fiber network.

    Science.gov (United States)

    Weyer, F; Duchesne, A; Vandewalle, N

    2017-10-17

    Lately, curious structures have been erected in arid regions: they are large nets able to catch water from fog. Tiny droplets condense on the mesh and are collected on the bottom of it. This innovative technology is crucial to obtain drinkable water in these inhospitable areas. Many studies aim to understand the behavior of droplets trapped on this entanglement of fibers. However, the motion of a droplet sliding on a network of inclined fibers and encountering several crossings when going down remains an open question. Here, we look at the path chosen by such a drop and, especially, we analyze its behavior at the different nodes of the array. We show that droplets may change from one fiber to another one depending on the slope and the diameter of these fibers. We prove that we can force a droplet to follow a specific path simply by carefully designing the fiber mesh. These findings are expected to provide a very convenient way to manipulate small droplets in applications from microfluidics to fog harvesting.

  3. Adaptive Synchronization of Complex Dynamical Networks Governed by Local Lipschitz Nonlinearlity on Switching Topology

    Directory of Open Access Journals (Sweden)

    Bo Liu

    2013-01-01

    Full Text Available This paper investigates the adaptive synchronization of complex dynamical networks satisfying the local Lipschitz condition with switching topology. Based on differential inclusion and nonsmooth analysis, it is proved that all nodes can converge to the synchronous state, even though only one node is informed by the synchronous state via introducing decentralized adaptive strategies to the coupling strengths and feedback gains. Finally, some numerical simulations are worked out to illustrate the analytical results.

  4. Distributed H∞ Sampled-Data Filtering over Sensor Networks with Markovian Switching Topologies

    Directory of Open Access Journals (Sweden)

    Bin Yang

    2014-01-01

    Full Text Available This paper considers a distributed H∞ sampled-data filtering problem in sensor networks with stochastically switching topologies. It is assumed that the topology switching is triggered by a Markov chain. The output measurement at each sensor is first sampled and then transmitted to the corresponding filters via a communication network. Considering the effect of a transmission delay, a distributed filter structure for each sensor is given based on the sampled data from itself and its neighbor sensor nodes. As a consequence, the distributed H∞ sampled-data filtering in sensor networks under Markovian switching topologies is transformed into H∞ mean-square stability problem of a Markovian jump error system with an interval time-varying delay. By using Lyapunov Krasovskii functional and reciprocally convex approach, a new bounded real lemma (BRL is derived, which guarantees the mean-square stability of the error system with a desired H∞ performance. Based on this BRL, the topology-dependent H∞ sampled-data filters are obtained. An illustrative example is given to demonstrate the effectiveness of the proposed method.

  5. Impact of Bimodal Traffic on Latency in Optical Burst Switching Networks

    Directory of Open Access Journals (Sweden)

    Yuhua Chen

    2008-01-01

    Full Text Available This paper analyzes the impact of bimodal traffic composition on latency in optical burst switching networks. In particular, it studies the performance degradation to short-length packets caused by longer packets, both of which are part of a heterogeneous traffic model. The paper defines a customer satisfaction index for each of the classes of traffic, and a composite satisfaction index. The impact of higher overall utilization of the network as well as that of the ratio of the traffic mix on each of the customer satisfaction indices is specifically addressed.

  6. A novel ingress node design for video streaming over optical burst switching networks.

    Science.gov (United States)

    Askar, S; Zervas, G; Hunter, D K; Simeonidou, D

    2011-12-12

    This paper introduces a novel ingress node design which takes advantage of video data partitioning in order to deliver enhanced video streaming quality when using H.264/AVC codec over optical burst switching networks. Ns2 simulations show that the proposed scheme delivers improved video traffic quality without affecting other traffic, such as best effort traffic. Although the extra network load is comparatively small, the average gain in video PSNR was 5 dB over existing burst cloning schemes, with a maximum end-to-end delay of 17 ms, and jitter of less than 0.35 ms. © 2011 Optical Society of America

  7. Power Electronic Systems for Switched Reluctance Generator based Wind Farms and DC Networks

    DEFF Research Database (Denmark)

    Park, Kiwoo

    . Under these circumstances, research on dc network connection with a novel wind power generator system is presented in this thesis, which mainly consists of two major parts: control of a Switched Reluctance Generator (SRG) system and development of dc-dc converters for a dc network system in a wind farm...... components into the torque reference to compensate the ripples in the actual output torque. The effectiveness and resulting improvement in the performance of both the proposed speed controller and torque minimization technique are demonstrated by simulation results. The modern power electronic interfaces...

  8. A note on the consensus finding problem in communication networks with switching topologies

    KAUST Repository

    Haskovec, Jan

    2014-05-07

    In this note, we discuss the problem of consensus finding in communication networks of agents with dynamically switching topologies. In particular, we consider the case of directed networks with unbalanced matrices of communication rates. We formulate sufficient conditions for consensus finding in terms of strong connectivity of the underlying directed graphs and prove that, given these conditions, consensus is found asymptotically. Moreover, we show that this consensus is an emergent property of the system, being encoded in its dynamics and not just an invariant of its initial configuration. © 2014 © 2014 Taylor & Francis.

  9. A NOVEL HYBRID SCHEME FOR CONTENTION MINIMIZATION IN OPTICAL BURST SWITCHED NETWORK

    Directory of Open Access Journals (Sweden)

    Dilip H. Patel

    2015-12-01

    Full Text Available In Optical Burst Switched (OBS Networks, data is transported in a bufferless network and hence there is fair amount of possibility of contention among the data bursts. This occurs when multiple bursts contend for the same link. The existing reactive contention resolution schemes attempt to address issue of contention without making any efforts to minimize the occurrences of contention in the network. Also, the existing proactive contention minimization schemes fail to provide improvement in contention loss at a very high load. Therefore, we are presenting new scheme for reducing the occurrence of contention in OBS network and it is known as Dynamic Hybrid Cluster and Deflection Feedback (DHCF scheme. In proposed DHCF scheme entire OBS network is partitioned into many small clusters. In each cluster, one node acts as cluster head for gathering the information of resources in the network. The contention is minimized using clustering approach and it can be further improved with the help of deflection feedback mechanism. A performance metrics is considered to evaluate merits of the proposed DHCF scheme and its effects on overall network performance. Also, the comparison of the performance of the DHCF scheme with limited hybrid deflection and retransmission (LHDR scheme and dynamic hybrid retransmission in deflection routing (DHRD scheme is made. The simulation results show that the proposed scheme gives improvement in Burst Loss Probability (BLP in the range of 31% to 38% and delay improvement in the range of 64% to 74% on vBSN network. The vBSN is network topology.

  10. FAST TCP over optical burst switched networks: Modeling and stability analysis

    KAUST Repository

    Shihada, Basem

    2013-04-01

    FAST TCP is important for promoting data-intensive applications since it can cleverly react to both packet loss and delay for detecting network congestion. This paper provides a continuous time model and extensive stability analysis of FAST TCP congestion-control mechanism in bufferless Optical Burst Switched Networks (OBS). The paper first shows that random burst contentions are essential to stabilize the network, but cause throughput degradation in FAST TCP flows when a burst with all the packets from a single round is dropped. Second, it shows that FAST TCP is vulnerable to burst delay and fails to detect network congestion due to the little variation of round-trip time, thus unstable. Finally it shows that introducing extra delays by implementing burst retransmission stabilizes FAST TCP over OBS. The paper proves that FAST TCP is not stable over barebone OBS. However, it is locally, exponentially, and asymptotically stable over OBS with burst retransmission.

  11. Stochastic Spiking Neural Networks Enabled by Magnetic Tunnel Junctions: From Nontelegraphic to Telegraphic Switching Regimes

    Science.gov (United States)

    Liyanagedera, Chamika M.; Sengupta, Abhronil; Jaiswal, Akhilesh; Roy, Kaushik

    2017-12-01

    Stochastic spiking neural networks based on nanoelectronic spin devices can be a possible pathway to achieving "brainlike" compact and energy-efficient cognitive intelligence. The computational model attempt to exploit the intrinsic device stochasticity of nanoelectronic synaptic or neural components to perform learning or inference. However, there has been limited analysis on the scaling effect of stochastic spin devices and its impact on the operation of such stochastic networks at the system level. This work attempts to explore the design space and analyze the performance of nanomagnet-based stochastic neuromorphic computing architectures for magnets with different barrier heights. We illustrate how the underlying network architecture must be modified to account for the random telegraphic switching behavior displayed by magnets with low barrier heights as they are scaled into the superparamagnetic regime. We perform a device-to-system-level analysis on a deep neural-network architecture for a digit-recognition problem on the MNIST data set.

  12. Synchronization Algorithm for SDN-controlled All-Optical TDM Switching in a Random Length Ring Network

    DEFF Research Database (Denmark)

    Kamchevska, Valerija; Cristofori, Valentina; Da Ros, Francesco

    2016-01-01

    We propose and demonstrate an algorithm that allows for automatic synchronization of SDN-controlled all-optical TDM switching nodes connected in a ring network. We experimentally show successful WDM-SDM transmission of data bursts between all ring nodes.......We propose and demonstrate an algorithm that allows for automatic synchronization of SDN-controlled all-optical TDM switching nodes connected in a ring network. We experimentally show successful WDM-SDM transmission of data bursts between all ring nodes....

  13. Burst switching without guard interval in all-optical software-define star intra-data center network

    Science.gov (United States)

    Ji, Philip N.; Wang, Ting

    2014-02-01

    Optical switching has been introduced in intra-data center networks (DCNs) to increase capacity and to reduce power consumption. Recently we proposed a star MIMO OFDM-based all-optical DCN with burst switching and software-defined networking. Here, we introduce the control procedure for the star DCN in detail for the first time. The timing, signaling, and operation are described for each step to achieve efficient bandwidth resource utilization. Furthermore, the guidelines for the burst assembling period selection that allows burst switching without guard interval are discussed. The star all-optical DCN offers flexible and efficient control for next-generation data center application.

  14. Neural network-based sliding mode control for atmospheric-actuated spacecraft formation using switching strategy

    Science.gov (United States)

    Sun, Ran; Wang, Jihe; Zhang, Dexin; Shao, Xiaowei

    2018-02-01

    This paper presents an adaptive neural networks-based control method for spacecraft formation with coupled translational and rotational dynamics using only aerodynamic forces. It is assumed that each spacecraft is equipped with several large flat plates. A coupled orbit-attitude dynamic model is considered based on the specific configuration of atmospheric-based actuators. For this model, a neural network-based adaptive sliding mode controller is implemented, accounting for system uncertainties and external perturbations. To avoid invalidation of the neural networks destroying stability of the system, a switching control strategy is proposed which combines an adaptive neural networks controller dominating in its active region and an adaptive sliding mode controller outside the neural active region. An optimal process is developed to determine the control commands for the plates system. The stability of the closed-loop system is proved by a Lyapunov-based method. Comparative results through numerical simulations illustrate the effectiveness of executing attitude control while maintaining the relative motion, and higher control accuracy can be achieved by using the proposed neural-based switching control scheme than using only adaptive sliding mode controller.

  15. Controlling Depth of Cellular Quiescence by an Rb-E2F Network Switch

    Directory of Open Access Journals (Sweden)

    Jungeun Sarah Kwon

    2017-09-01

    Full Text Available Quiescence is a non-proliferative cellular state that is critical to tissue repair and regeneration. Although often described as the G0 phase, quiescence is not a single homogeneous state. As cells remain quiescent for longer durations, they move progressively deeper and display a reduced sensitivity to growth signals. Deep quiescent cells, unlike senescent cells, can still re-enter the cell cycle under physiological conditions. Mechanisms controlling quiescence depth are poorly understood, representing a currently underappreciated layer of complexity in growth control. Here, we show that the activation threshold of a Retinoblastoma (Rb-E2F network switch controls quiescence depth. Particularly, deeper quiescent cells feature a higher E2F-switching threshold and exhibit a delayed traverse through the restriction point (R-point. We further show that different components of the Rb-E2F network can be experimentally perturbed, following computer model predictions, to coarse- or fine-tune the E2F-switching threshold and drive cells into varying quiescence depths.

  16. Prototyping and Testing a Wireless Sensor Network to Retrieve SWE at High Spatial Resolution

    Science.gov (United States)

    Kang, D.; Barros, A. P.

    2007-12-01

    A critical challenge in snow research from space is the ability to obtain measurements at the spatial and temporal resolution to characterize the statistical structure of the space-time variability of the physical properties of the snowpack within an area consistent with the pixel resolution in snow hydrology models or that expected from a future NASA mission dedicated to cold region processes. That is, observations of relevant snow dielectric properties are necessary at high spatial and temporal resolution during the accumulation and melt seasons. We present a new wireless sensor network prototype consisting of multiple antennas and buried low-power, multi- channel transmitters operating in L-band that communicate to a central pod equipped with a Vector Signal Analyzer (VSA) that receives, processes and manages the data. Only commercial off-the-shelf hard-ware parts were used to build the sensors. Because the sensors are very low cost and run autonomously, one envisions that self-organizing networks of large numbers of such sensors might be distributed over very large areas, therefore proving much needed data sets for scaling studies. The measurement strategy consists of placing the transmitters the land surface in the beginning of the snow season which are then run autonomously till the end of the spring and waken at pre-determined time-intervals to emit radio frequency signals and thus sample the snowpack. Along with the sensors, an important component of this work entails the development of an estimation algorithm to estimate snow dielectric properties, snow density, and volume fraction of snow (VF) from the time-of-travel, amplitude and phase modification of the multi-channel RF signals as they propagate through the snow-pack. Here, we present results from full system testing and evaluation of the sensors that were conducted at Duke University using ¢®¡Æsynthetic¢®¡¾ limited-area snowpacks (0.5 by 0.5 m2 and 1 by 2 m2) constructed of various

  17. Content Aware Burst Assembly - Supporting Telesurgery and Telemedicine in Optical Burst Switching Networks

    Directory of Open Access Journals (Sweden)

    Henry Orosco

    2010-08-01

    Full Text Available The emerging Telemedicine and Telesurgery technologies allow patients to share medical experts remotely through communication networks. However, network bandwidth, network latency and jitter (variation of latency, are the obstacles to the widespread use of this technology remotely. Optical Burst Switching (OBS networks greatly expand network bandwidth in existing network infrastructure by utilizing multiple DWDM channels within a single fiber, enabling high bandwidth applications. However, the burst assembly process in OBS networks introduces latency and jitter, making it unsuitable for high bandwidth, latency sensitive applications such as telesurgery and telemedicine. In this paper, we propose a content aware burst assembly scheme which dynamically adjusts the burst assembly parameters based on the content being assembled. The proposed content aware burst assembly minimizes the latency and jitter within a video frame, as well as across the left-view and right-view frames for 3D vision generation. Simulation results have shown that the proposed scheme can effectively reduce the latency and jitter experienced by video streams, making OBS a promising candidate for supporting telesurgery and telemedicine applications.

  18. Energy-Efficient Distributed Filtering in Sensor Networks: A Unified Switched System Approach.

    Science.gov (United States)

    Zhang, Dan; Shi, Peng; Zhang, Wen-An; Yu, Li

    2016-04-21

    This paper is concerned with the energy-efficient distributed filtering in sensor networks, and a unified switched system approach is proposed to achieve this goal. For the system under study, the measurement is first sampled under nonuniform sampling periods, then the local measurement elements are selected and quantized for transmission. Then, the transmission rate is further reduced to save constrained power in sensors. Based on the switched system approach, a unified model is presented to capture the nonuniform sampling, the measurement size reduction, the transmission rate reduction, the signal quantization, and the measurement missing phenomena. Sufficient conditions are obtained such that the filtering error system is exponentially stable in the mean-square sense with a prescribed H∞ performance level. Both simulation and experiment studies are given to show the effectiveness of the proposed new design technique.

  19. A novel contention solution strategy based on priority for optical burst switching networks

    Science.gov (United States)

    Guan, Ai-Hong; Cui, Fang-Fang

    2010-11-01

    A fundamental issue in optical burst switching (OBS) networks is to solve the burst contention for the core node. In this paper, a novel priority-based contention solution strategy for OBS networks is proposed. When the contention occurs, the burst priority is considered firstly, and then the burst segmentation method is used for the low priority bursts in this strategy. Ensuring the integrity of high priority bursts, part of the segmented bursts can be transmitted to the destination node via combining wavelength conversion and optical buffer method. Simulation results show that the proposed scheme not only ensures the integrity of high priority bursts, but also reduces the packet loss rate of the low priority bursts maximally, so that it can support good quality of service (QoS) for the network.

  20. Experimental Results of Network-Assisted Interference Suppression Scheme Using Adaptive Beam-Tilt Switching

    Directory of Open Access Journals (Sweden)

    Tomoki Murakami

    2017-01-01

    Full Text Available This paper introduces a network-assisted interference suppression scheme using beam-tilt switching per frame for wireless local area network systems and its effectiveness in an actual indoor environment. In the proposed scheme, two access points simultaneously transmit to their own desired station by adjusting angle of beam-tilt including transmit power assisted from network server for the improvement of system throughput. In the conventional researches, it is widely known that beam-tilt is effective for ICI suppression in the outdoor scenario. However, the indoor effectiveness of beam-tilt for ICI suppression has not yet been indicated from the experimental evaluation. Thus, this paper indicates the effectiveness of the proposed scheme by analyzing multiple-input multiple-output channel matrices from experimental measurements in an office environment. The experimental results clearly show that the proposed scheme offers higher system throughput than the conventional scheme using just transmit power control.

  1. Emergence of switch-like behavior in a large family of simple biochemical networks.

    Directory of Open Access Journals (Sweden)

    Dan Siegal-Gaskins

    2011-05-01

    Full Text Available Bistability plays a central role in the gene regulatory networks (GRNs controlling many essential biological functions, including cellular differentiation and cell cycle control. However, establishing the network topologies that can exhibit bistability remains a challenge, in part due to the exceedingly large variety of GRNs that exist for even a small number of components. We begin to address this problem by employing chemical reaction network theory in a comprehensive in silico survey to determine the capacity for bistability of more than 40,000 simple networks that can be formed by two transcription factor-coding genes and their associated proteins (assuming only the most elementary biochemical processes. We find that there exist reaction rate constants leading to bistability in ∼90% of these GRN models, including several circuits that do not contain any of the TF cooperativity commonly associated with bistable systems, and the majority of which could only be identified as bistable through an original subnetwork-based analysis. A topological sorting of the two-gene family of networks based on the presence or absence of biochemical reactions reveals eleven minimal bistable networks (i.e., bistable networks that do not contain within them a smaller bistable subnetwork. The large number of previously unknown bistable network topologies suggests that the capacity for switch-like behavior in GRNs arises with relative ease and is not easily lost through network evolution. To highlight the relevance of the systematic application of CRNT to bistable network identification in real biological systems, we integrated publicly available protein-protein interaction, protein-DNA interaction, and gene expression data from Saccharomyces cerevisiae, and identified several GRNs predicted to behave in a bistable fashion.

  2. A PROTOTYPE OF BARENTSNET PROFESSIONAL SOCIAL NETWORK FOR INFORMATION SUPPORT OF DEVELOPMENT MANAGEMENT FOR BARENTS EURO-ARCTIC REGION

    OpenAIRE

    Andrey V. Masloboev; Remi Strand

    2014-01-01

    A prototype of professional social network BarentsNet has been developed for management activities information support of entities participating in the management process of developing and resource potential settling of the Barents EuroArctic region. BarentsNet system is implemented as a multi-domain web-service and provides formalized ontology-based expert knowledge integration of the Arctic and sub-Arctic territories development features, and professional contacts linking automa...

  3. A novel implementation of TCP Vegas for optical burst switched networks

    KAUST Repository

    Shihada, Basem

    2010-07-01

    TCP performance over bufferless Optical Burst Switched (OBS) networks could be significantly degraded due to the misinterpretation of network congestion status (referred to as false congestion detection). It has been reported that burst retransmission in the OBS domain can improve the TCP throughput by hiding burst loss events from the upper TCP layer, which can effectively reduce the congestion window fluctuation at the expense of introducing additional delay. However, the additional delay may cause performance degradation for delay-based TCP implementations that are sensitive to packet round trip time in estimating the network congestion status. In this paper, a novel implementation of TCP Vegas that adopts a threshold-based mechanism is proposed for identifying the network congestion status in OBS networks. Analytical models are developed to evaluate the throughput of conventional TCP Vegas and threshold-based Vegas over OBS networks with burst retransmission. Simulation is conducted to validate the analytical model and to compare threshold-based Vegas with a number of legacy TCP implementations, such as TCP Sack and TCP Reno. The analytical model can be used to obtain a proper threshold value that results in an optimal steady state TCP throughput.

  4. Stacked optical code label for multicasting in optical packet switching networks.

    Science.gov (United States)

    Xin, Ming; Chen, Minghua; Chen, Hongwei; Xie, Shizhong

    2009-03-16

    Stacked optical code (OC) label and its en/decoder based on fiber Bragg gratings (FBG) are proposed and experimentally demonstrated. This kind of label can carry several nodes' address information simultaneously in optical packet switching networks, so it can be employed in optical multicasting and simplify the node's structure a lot. The en/decoder is fabricated with high precision by our FBG techniques, and the experiment results show that the stacked OC label can support optical multicasting very well. (c) 2009 Optical Society of America

  5. Validation Techniques of network harmonic models based on switching of a series linear component and measuring resultant harmonic increments

    DEFF Research Database (Denmark)

    Wiechowski, Wojciech Tomasz; Lykkegaard, Jan; Bak, Claus Leth

    2007-01-01

    In this paper two methods of validation of transmission network harmonic models are introduced. The methods were developed as a result of the work presented in [1]. The first method allows calculating the transfer harmonic impedance between two nodes of a network. Switching a linear, series network...... are used for calculation of the transfer harmonic impedance between the nodes. The determined transfer harmonic impedance can be used to validate a computer model of the network. The second method is an extension of the fist one. It allows switching a series element that contains a shunt branch...... component that links the nodes causes a variation of the background harmonic voltage distortion at the nodes. Harmonic current in the series element is measured together with the harmonic voltages at both nodes, before and after the switching. Obtained incremental values of harmonic voltages and the current...

  6. Switching between executive and default mode networks in posttraumatic stress disorder: alterations in functional connectivity

    Science.gov (United States)

    Daniels, Judith K.; McFarlane, Alexander C.; Bluhm, Robyn L.; Moores, Kathryn A.; Clark, C. Richard; Shaw, Marnie E.; Williamson, Peter C.; Densmore, Maria; Lanius, Ruth A.

    2010-01-01

    Background Working memory processing and resting-state connectivity in the default mode network are altered in patients with post-traumatic stress disorder (PTSD). Because the ability to effortlessly switch between concentration on a task and an idling state during rest is implicated in both these alterations, we undertook a functional magnetic resonance imaging study with a block design to analyze task-induced modulations in connectivity. Methods We performed a working memory task and psychophysiologic interaction analyses with the posterior cingulate cortex and the medial prefrontal cortex as seed regions during fixation in 12 patients with severe, chronic PTSD and 12 healthy controls. Results During the working memory task, the control group showed significantly stronger connectivity with areas implicated in the salience and executive networks, including the right inferior frontal gyrus and the right inferior parietal lobule. The PTSD group showed stronger connectivity with areas implicated in the default mode network, namely enhanced connectivity between the posterior cingulate cortex and the right superior frontal gyrus and between the medial prefrontal cortex and the left parahip-pocampal gyrus. Limitations Because we were studying alterations in patients with severe, chronic PTSD, we could not exclude patients taking medication. The small sample size may have limited the power of our analyses. To avoid multiple testing in a small sample, we only used 2 seed regions for our analyses. Conclusion The different patterns of connectivity imply significant group differences with task-induced switches (i.e., engaging and disengaging the default mode network and the central-executive network). PMID:20569651

  7. Reducing Spectrum Handoffs and Energy Switching Consumption of MADM-Based Decisions in Cognitive Radio Networks

    Directory of Open Access Journals (Sweden)

    Rafael Aguilar-Gonzalez

    2016-01-01

    Full Text Available In a cognitive radio network (CRN, the number of spectrum handoffs increases energy consumption of cognitive (or secondary users due to the channel switching process. This might limit the operation of the CRN, especially in scenarios where secondary users terminals are battery-powered. Thus, reducing the number of times a cognitive user involved in a transmission switch to different spectrum holes is required to increase battery life-time. In this regard, available spectrum holes possess different attributes (e.g., bandwidth that can be exploited to satisfy specific secondary users requirements (i.e., connection profile for data transmission while saving energy. Here, three multiple attribute decision-making (MADM algorithms for the spectrum decision functionality are evaluated using real spectrum measurements of TV bands. This is performed by proposing six decision parameters, which are extracted from the spectrum data to characterize its suitability. Then, these are used as inputs of the MADM algorithms to select the most suitable spectrum hole for a cognitive user. Thus, an enhanced MADM-based decision process is proposed to reduce the number of handoffs considering energy consumption due to channel switching (ECCS. Results quantify savings from 30% to 90% in ECCS and spectrum handoffs reductions from 47% to 90%.

  8. A First Step Towards Network Security Virtualization: From Concept to Prototype

    Science.gov (United States)

    2015-10-01

    installed (fixed-location) security devices and leverage software-defined networking ( SDN ) technology to virtualize network security functions. At its core...network device. Some recent technologies suggest a method to control network flows dynamically at a network device, e.g., Software-Defined Networking ( SDN ...Software- Defined Networking ( SDN ) technology and its most popular realization, OpenFlow [17], [24]. More specifically, we will use SDN /OpenFlow to

  9. High-performance flat data center network architecture based on scalable and flow-controlled optical switching system

    Science.gov (United States)

    Calabretta, Nicola; Miao, Wang; Dorren, Harm

    2016-03-01

    Traffic in data centers networks (DCNs) is steadily growing to support various applications and virtualization technologies. Multi-tenancy enabling efficient resource utilization is considered as a key requirement for the next generation DCs resulting from the growing demands for services and applications. Virtualization mechanisms and technologies can leverage statistical multiplexing and fast switch reconfiguration to further extend the DC efficiency and agility. We present a novel high performance flat DCN employing bufferless and distributed fast (sub-microsecond) optical switches with wavelength, space, and time switching operation. The fast optical switches can enhance the performance of the DCNs by providing large-capacity switching capability and efficiently sharing the data plane resources by exploiting statistical multiplexing. Benefiting from the Software-Defined Networking (SDN) control of the optical switches, virtual DCNs can be flexibly created and reconfigured by the DCN provider. Numerical and experimental investigations of the DCN based on the fast optical switches show the successful setup of virtual network slices for intra-data center interconnections. Experimental results to assess the DCN performance in terms of latency and packet loss show less than 10^-5 packet loss and 640ns end-to-end latency with 0.4 load and 16- packet size buffer. Numerical investigation on the performance of the systems when the port number of the optical switch is scaled to 32x32 system indicate that more than 1000 ToRs each with Terabit/s interface can be interconnected providing a Petabit/s capacity. The roadmap to photonic integration of large port optical switches will be also presented.

  10. Proposal of Novel Optical Burst Signal Receiver for ONU in Optical Switched Access Network

    Science.gov (United States)

    Ueda, Hiromi; Hamasaki, Keita; Kuriyama, Takashi; Tsuboi, Toshinori; Kasai, Hiroyuki

    To realize economical optical burst signal receivers for the Optical Network Unit (ONU) of the Ethernet Optical Switched Access Network (E-OSAN), we previously implemented optical burst receivers with AC-coupling and DC-coupling using off-the-shelf components, and showed that the former offers better performance. This paper proposes a new optical burst signal receiver that uses the transfer function, Gn(s) =1-Hn(s), where Hn(s) denotes a Bessel filter transfer function of order n. We also present a method for designing the proposed receiver and clarify that it has better performance than the conventional AC-coupling one. We then present an LCR circuit synthesis of Gn(s), which is necessary to actually implement a burst receiver based on the proposal.

  11. Cooperative output regulation with application to multi-agent consensus under switching network.

    Science.gov (United States)

    Su, Youfeng; Huang, Jie

    2012-06-01

    In this paper, we consider the cooperative output regulation of linear multi-agent systems under switching network. The problem can be viewed as a generalization of the leader-following consensus problem of multi-agent systems. Due to the limited information exchanges of different subsystems, the problem cannot be solved by the decentralized approach and is not allowed to be solved by the centralized control. By devising a distributed observer network, we can solve the problem by both dynamic state feedback control and dynamic measurement output feedback control. As an application of our main result, we show that a special case of our results leads to the solution of the leader-following consensus problem of linear multi-agent systems.

  12. The Control of Fluxes of Electric Power in Networks by Means of Phase-switching Booster Transformers

    Directory of Open Access Journals (Sweden)

    Govorov F.P.

    2016-12-01

    Full Text Available roblems of increasing the efficiency of the operation of electrical networks based on the utilization of booster transformers (BT with electronic control, applied on the base of active elements in smart electric grids of power systems and giving the function of automatic correction of the parameters of the network, assuring the conditions of optimal common operation are studied in the paper. The mathematic model of the processes in the electric networks with booster transformer has been developed; the opportunity of control by means of the phase-switching BT for power fluxes in the networks has been established. It has been shown that for the groups of switching the windings 1-5 of BT occurs additional consumption of power from the supply network, but for the groups 7-11 its recuperation to the load network. Respectively, switching the windings of BT to the group 1-5 assures the shift of load current to the direction of lag, but in the case of switching to the group 7-11 – towards the outrunning. Wherein, for the groups of switching 10-11 and 1-2 one can observe the increasing of the voltage at the output of BT, but for the groups 7-8 and 4-5 it is decreasing. Based on the analysis of the results of research the diagram and constructive models of the transformer have been proposed. The quasi-stationary and transient regimes were investigated and the conditions of reliable operation at these the regimes have been determined. The ways for increasing the efficient common operation for the transformer and network in the case of switching the thyristors into the circuit of the primary winding of the transformer have been proposed.

  13. Secured Hash Based Burst Header Authentication Design for Optical Burst Switched Networks

    Science.gov (United States)

    Balamurugan, A. M.; Sivasubramanian, A.; Parvathavarthini, B.

    2017-12-01

    The optical burst switching (OBS) is a promising technology that could meet the fast growing network demand. They are featured with the ability to meet the bandwidth requirement of applications that demand intensive bandwidth. OBS proves to be a satisfactory technology to tackle the huge bandwidth constraints, but suffers from security vulnerabilities. The objective of this proposed work is to design a faster and efficient burst header authentication algorithm for core nodes. There are two important key features in this work, viz., header encryption and authentication. Since the burst header is an important in optical burst switched network, it has to be encrypted; otherwise it is be prone to attack. The proposed MD5&RC4-4S based burst header authentication algorithm runs 20.75 ns faster than the conventional algorithms. The modification suggested in the proposed RC4-4S algorithm gives a better security and solves the correlation problems between the publicly known outputs during key generation phase. The modified MD5 recommended in this work provides 7.81 % better avalanche effect than the conventional algorithm. The device utilization result also shows the suitability of the proposed algorithm for header authentication in real time applications.

  14. Switched-based interference reduction scheme for open-access overlaid cellular networks

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2012-06-01

    Femtocells have been proposed to enhance the spatial coverage and system capacity of existing cellular networks. However, this technology may result in significant performance loss due to the increase in co-channel interference, particularly when coordination between access points is infeasible. This paper targets interference management in such overlaid networks. It is assumed that the femtocells employ the open-access strategy to reduce cross-tier interference, and can share resources concurrently. It is also assumed that each end user (EU) can access one channel at a time, and transfer limited feedback. To reduce the effect of co-tier interference in the absence of the desired EU channel state information (CSI) at the serving access point as well as coordination between active access points, a switched scheme based on the interference levels associated with available channels is proposed. Through the analysis, the scheme modes of operation in under-loaded and over-loaded channels are studied, from which the statistics of the resulting interference power are quantified. The impact of the proposed scheme on the received desired power is thoroughly discussed. In addition, the effect of the switching threshold on the achieved performance of the desired EU is investigated. The results clarify that the proposed scheme can improve the performance while reducing the number of examined channels and feedback load. © 2012 IEEE.

  15. Quasi-Optical Network Analyzers and High-Reliability RF MEMS Switched Capacitors

    Science.gov (United States)

    Grichener, Alexander

    The thesis first presents a 2-port quasi-optical scalar network analyzer consisting of a transmitter and receiver both built in planar technology. The network analyzer is based on a Schottky-diode mixer integrated inside a planar antenna and fed differentially by a CPW transmission line. The antenna is placed on an extended hemispherical high-resistivity silicon substrate lens. The LO signal is swept from 3-5 GHz and high-order harmonic mixing in both up- and down- conversion mode is used to realize the 15-50 GHz RF bandwidth. The network analyzer resulted in a dynamic range of greater than 40 dB and was successfully used to measure a frequency selective surface with a second-order bandpass response. Furthermore, the system was built with circuits and components for easy scaling to millimeter-wave frequencies which is the primary motivation for this work. The application areas for a millimeter and submillimeter-wave network analyzer include material characterization and art diagnostics. The second project presents several RF MEMS switched capacitors designed for high-reliability operation and suitable for tunable filters and reconfigurable networks. The first switched-capacitor resulted in a digital capacitance ratio of 5 and an analog capacitance ratio of 5-9. The analog tuning of the down-state capacitance is enhanced by a positive vertical stress gradient in the the beam, making it ideal for applications that require precision tuning. A thick electroplated beam resulted in Q greater than 100 at C to X-band frequencies, and power handling of 0.6-1.1 W. The design also minimized charging in the dielectric, resulting in excellent reliability performance even under hot-switched and high power (1 W) conditions. The second switched-capacitor was designed without any dielectric to minimize charging. The device was hot-switched at 1 W of RF power for greater than 11 billion cycles with virtually no change in the C-V curve. The final project presents a 7-channel

  16. Synchronization in a Random Length Ring Network for SDN-Controlled Optical TDM Switching

    DEFF Research Database (Denmark)

    Kamchevska, Valerija; Cristofori, Valentina; Da Ros, Francesco

    2016-01-01

    In this paper we focus on optical time division multiplexed (TDM) switching and its main distinguishing characteristics compared with other optical subwavelength switching technologies. We review and discuss in detail the synchronization requirements that allow for proper switching operation. In ...

  17. Experimental free-space optical network for massively parallel computers.

    Science.gov (United States)

    Araki, S; Kajita, M; Kasahara, K; Kubota, K; Kurihara, K; Redmond, I; Schenfeld, E; Suzaki, T

    1996-03-10

    A free-space optical interconnection scheme is described for massively parallel processors based on the interconnection-cached network architecture. The optical network operates in a circuit-switching mode. Combined with a packet-switching operation among the circuit-switched optical channels, a high-bandwidth, low-latency network for massively parallel processing results. The design and assembly of a 64-channel experimental prototype is discussed, and operational results are presented.

  18. Monolithic InP-based fast optical switch module for optical networks of the future

    DEFF Research Database (Denmark)

    Xi, Chen; Regan, James; Durrant, Tim

    2015-01-01

    We summarized the development of Venture Photonics’ sub-10 ns fast optical switch which demonstrates low insertion loss, excellent crosstalk level and polarization independent switching performance....

  19. Path correlation considered prioritized burst segmentation for quality of service support in optical burst switching networks

    Science.gov (United States)

    Hou, Rui; Changyue, Jiana; He, Tingting; Yu, Jianwei; Lei, Bo; Mao, Tengyue

    2013-04-01

    Burst segmentation (BS) is a high-efficiency contention resolution scheme in bufferless optical burst switching (OBS) networks. A prioritized BS scheme for quality of service (QoS) support is developed. Unlike the existing work on the BS scheme, the proposed BS model considers path-correlated factors, such as path length, the adjoining paths carrying traffic on a given path, and the multipriority traffic coming from all paths. Byte loss probability for high-priority and low-priority bursts under the time-based assembly approach and the length-based assembly approach to estimate the performance of the proposed BS scheme by comparing the cumulative distribution function of a burst length in an OBS ingress node (source) with that in an egress node (destination) is introduced. A preemptive BS policy for different priority bursts is proposed to support the QoS of the OBS network. Finally, a simulation is given to validate the proposed analytical model in an existing OBS network with two priority bursts. It is shown that the proposed BS scheme can realize the service differentiation for multipriority traffic under the consideration of network topology-dependent parameters.

  20. Optimal design of mixed-media packet-switching networks - Routing and capacity assignment

    Science.gov (United States)

    Huynh, D.; Kuo, F. F.; Kobayashi, H.

    1977-01-01

    This paper considers a mixed-media packet-switched computer communication network which consists of a low-delay terrestrial store-and-forward subnet combined with a low-cost high-bandwidth satellite subnet. We show how to route traffic via ground and/or satellite links by means of static, deterministic procedures and assign capacities to channels subject to a given linear cost such that the network average delay is minimized. Two operational schemes for this network model are investigated: one is a scheme in which the satellite channel is used as a slotted ALOHA channel; the other is a new multiaccess scheme we propose in which whenever a channel collision occurs, retransmission of the involved packets will route through ground links to their destinations. The performance of both schemes is evaluated and compared in terms of cost and average packet delay tradeoffs for some examples. The results offer guidelines for the design and optimal utilization of mixed-media networks.

  1. Group scheduling based on control-packet batch processing in optical burst switched networks

    Science.gov (United States)

    Yuan, Chi; Li, Zhengbin; He, Yongqi; Xu, Anshi

    2007-11-01

    Optical burst switching (OBS) is proposed as a high-speed, flexible, and transparent technology. It is thought to be the best way to adapt the bursty IP traffic over optical wavelength division multiplexing (WDM) networks. OBS technology facilitates the efficient integration of both IP and WDM. It provides statistical multiplexing gains and avoids long end to end setup time of traditional virtual circuit configuration. However, there are still a lot of challenges, one of which is burst contention. Owing to the fact that random access memory like buffering is not available in the optical domain at present, there exists a real possibility that bursts may contend with one another at a switching node. Many contention resolutions are proposed. The major contention resolutions in literature are wavelength conversion, fiber delay lines, and deflecting routing. In this paper, a new data burst scheduling scheme, called group scheduling based on control-packet batch processing (GSCBP) was proposed to reduce burst contention. Like transmission control protocol, GSCBP has a batch processing window. Control packets which located in the batch processing window are batch processed. A heuristic scheduling algorithm arranges the relevant bursts' route based on the processing result and the network resource. A new node architecture supporting group scheduling was presented. The GSCBP algorithm is combined with wavelength converter and/or fiber delay lines which is shared by some data channels. Meanwhile, an extended open shortest path first (E-OSPF) routing strategy was proposed for OBS. Both GSCBP and E-OSPF are introduced into 14-node national science foundation network by means of simulations. The ETE delay, burst blocking probability, as well as burst dropping probability were attained. Results show that the GSBCP lead to the higher-priority traffic drop rate decrease one order of magnitude, if drop rate and ETE delay of lower priority traffic is sacrificed.

  2. Hardware and Software Co-design: An Architecture Proposal for a Network-on-Chip Switch based on Bufferless Data Flow

    Directory of Open Access Journals (Sweden)

    S. Ortega-Cisneros

    2014-02-01

    Full Text Available The use of on chip networks as interconnection media for systems implemented in FPGAs is limited by the amount of logical resources necessary to deploy the network in the target device, and the time necessary to adjust the network parameters to achieve the performance goal for the system. In this paper we present a switch architecture, with data flow control based on circuit switching and aimed for on-chip networks with a Spidergon topology, which seeks to reduce the area occupied without severely affecting the overall network performance. As a result, we obtained a switch that requires only 114 slices in its most economic version on a Virtex 4-device. We also provide a performance profile, obtained by subjecting a network formed by these switches to different synthetic workloads within a simulator. This simulator was developed as part of the design flow of the switch, and it proves to be an essential tool for the test and validation process.

  3. Verification and Validation of the GNSS Stations at the Prototype Core Site for NASA's Next Generation Space Geodesy Network

    Science.gov (United States)

    Desai, S. D.; Gross, J.; Haines, B. J.; Stowers, D. A.

    2013-12-01

    Two operational GNSS stations, GODN and GODS, were established within 100 m of each other at the prototype core site of NASA's next generation Space Geodesy Network. The planned network will co-locate each of the four space geodetic techniques, GNSS, SLR, VLBI, and DORIS, with the goal of meeting modern requirements for the International Terrestrial Reference Frame. This prototype site is located at NASA's Geophysical and Astronomical Observatory at the Goddard Space Flight Center. The two GNSS stations at the prototype site have been producing tracking data from the GPS, GLONASS, and Galileo constellations since January 17, 2012. We present results from the verification and validation of these two stations, focusing in particular on GPS-based positioning of these two sites to monitor their relative baseline vector. We compare baseline recovery from independent precise point positioning of each station to a network-based approach. We also show the impact on the baseline as well as station repeatability from various improvements to our processing approach, namely the application of empirical antenna calibrations, elevation-dependent weighting, and site-specific troposphere modeling. Together, these approaches have resulted in a factor of two improvement in the precision of the baseline length. The standard deviation of the baseline vector, when using independent precise positioning of each station, is 0.5, 0.4, 1.6, and 0.4 mm in the east, north, up, and length components. The difference between the GPS-based baseline length and that from an independent local tie survey is < 1 mm.

  4. On Asymptotic Analysis of Packet and Wormhole Switched Routing Algorithm for Application-Specific Networks-on-Chip

    Directory of Open Access Journals (Sweden)

    Nitin

    2012-01-01

    Full Text Available The application of the multistage interconnection networks (MINs in systems-on-chip (SoC and networks-on-chip (NoC is hottest since year 2002. Nevertheless, nobody used them practically for parallel communication. However, to overcome all the previous problems, a new method is proposed that uses MIN to provide intra-(global communication among application-specific NoCs in networks-in-package (NiP. For this, four fault-tolerant parallel algorithms are proposed. It allows different NoCs to communicate in parallel using either fault-tolerant irregular Penta multistage interconnection network (PNN or fault-tolerant regular Hexa multistage interconnection network (HXN. These two are acting as an interconnects-on-chip (IoC in NiP. Both IoC use packet switching and wormhole switching to route packets from source NoC to destination NoC. The results are compared in terms of packet losses and wormhole switching which comes out to be better than packet switching. The comparison of IoC on cost and MTTR concluded that the HXN has the higher cost than the PNN, but MTTR values of the HXN are low in comparison to the PNN. This signifies that the ability to tolerate faults and online repairing of the HXN is higher and faster than the PNN.

  5. A PROTOTYPE OF BARENTSNET PROFESSIONAL SOCIAL NETWORK FOR INFORMATION SUPPORT OF DEVELOPMENT MANAGEMENT FOR BARENTS EURO-ARCTIC REGION

    Directory of Open Access Journals (Sweden)

    Andrey V. Masloboev

    2014-09-01

    Full Text Available A prototype of professional social network BarentsNet has been developed for management activities information support of entities participating in the management process of developing and resource potential settling of the Barents EuroArctic region. BarentsNet system is implemented as a multi-domain web-service and provides formalized ontology-based expert knowledge integration of the Arctic and sub-Arctic territories development features, and professional contacts linking automation within the system for cooperation and joint project realization in this sphere. The functionality organization model, executive core and software components of the BarentsNet system have been developed.

  6. Final design of the Switching Network Units for the JT-60SA Central Solenoid

    Energy Technology Data Exchange (ETDEWEB)

    Lampasi, Alessandro, E-mail: alessandro.lampasi@enea.it [National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Frascati (Italy); Coletti, Alberto; Novello, Luca [Fusion for Energy (F4E) Broader Fusion Development Department, Garching (Germany); Matsukawa, Makoto [Japan Atomic Energy Agency, Naka Fusion Institute, Mukouyama, Naka-si, Ibaraki-ken (Japan); Burini, Filippo; Taddia, Giuseppe; Tenconi, Sandro [OCEM Energy Technology, San Giorgio Di Piano (Italy)

    2014-04-15

    This paper describes the approved detailed design of the four Switching Network Units (SNUs) of the superconducting Central Solenoid of JT-60SA, the satellite tokamak that will be built in Naka, Japan, in the framework of the “Broader Approach” cooperation agreement between Europe and Japan. The SNUs can interrupt a current of 20 kA DC in less than 1 ms in order to produce a voltage of 5 kV. Such performance is obtained by inserting an electronic static circuit breaker in parallel to an electromechanical contactor and by matching and coordinating their operations. Any undesired transient overvoltage is limited by an advanced snubber circuit optimized for this application. The SNU resistance values can be adapted to the specific operation scenario. In particular, after successful plasma breakdown, the SNU resistance can be reduced by a making switch. The design choices of the main SNU elements are justified by showing and discussing the performed calculations and simulations. In most cases, the developed design is expected to exceed the performances required by the JT-60SA project.

  7. Problem of Channel Utilization and Merging Flows in Buffered Optical Burst Switching Networks

    Directory of Open Access Journals (Sweden)

    Milos Kozak

    2013-01-01

    Full Text Available In the paper authors verify two problems of methods of operational research in optical burst switching. The first problem is at edge node, related to the medium access delay. The second problem is at an intermediate node related to buffering delay. A correction coefficient K of transmission speed is obtained from the first analysis. It is used in to provide a full-featured link of nominal data rate. Simulations of the second problem reveal interesting results. It is not viable to prepare routing and wavelength assignment based on end-to-end delay, i.e. link's length or number of hops, as commonly used in other frameworks (OCS, Ethernet, IP, etc. nowadays. Other parameters such as buffering probability must be taken into consideration as well. Based on the buffering probability an estimation of the number of optical/electrical converters can be made. This paper concentrates important traffic constraints of buffered optical burst switching. It allows authors to prepare optimization algorithms for regenerators placement in CAROBS networks using methods of operational research.

  8. Distributed reconfigurable control strategies for switching topology networked multi-agent systems.

    Science.gov (United States)

    Gallehdari, Z; Meskin, N; Khorasani, K

    2017-11-01

    In this paper, distributed control reconfiguration strategies for directed switching topology networked multi-agent systems are developed and investigated. The proposed control strategies are invoked when the agents are subject to actuator faults and while the available fault detection and isolation (FDI) modules provide inaccurate and unreliable information on the estimation of faults severities. Our proposed strategies will ensure that the agents reach a consensus while an upper bound on the team performance index is ensured and satisfied. Three types of actuator faults are considered, namely: the loss of effectiveness fault, the outage fault, and the stuck fault. By utilizing quadratic and convex hull (composite) Lyapunov functions, two cooperative and distributed recovery strategies are designed and provided to select the gains of the proposed control laws such that the team objectives are guaranteed. Our proposed reconfigurable control laws are applied to a team of autonomous underwater vehicles (AUVs) under directed switching topologies and subject to simultaneous actuator faults. Simulation results demonstrate the effectiveness of our proposed distributed reconfiguration control laws in compensating for the effects of sudden actuator faults and subject to fault diagnosis module uncertainties and unreliabilities. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  9. Bidirectional Control of Generalized Epilepsy Networks via Rapid Real-Time Switching of Firing Mode.

    Science.gov (United States)

    Sorokin, Jordan M; Davidson, Thomas J; Frechette, Eric; Abramian, Armen M; Deisseroth, Karl; Huguenard, John R; Paz, Jeanne T

    2017-01-04

    Thalamic relay neurons have well-characterized dual firing modes: bursting and tonic spiking. Studies in brain slices have led to a model in which rhythmic synchronized spiking (phasic firing) in a population of relay neurons leads to hyper-synchronous oscillatory cortico-thalamo-cortical rhythms that result in absence seizures. This model suggests that blocking thalamocortical phasic firing would treat absence seizures. However, recent in vivo studies in anesthetized animals have questioned this simple model. Here we resolve this issue by developing a real-time, mode-switching approach to drive thalamocortical neurons into or out of a phasic firing mode in two freely behaving genetic rodent models of absence epilepsy. Toggling between phasic and tonic firing in thalamocortical neurons launched and aborted absence seizures, respectively. Thus, a synchronous thalamocortical phasic firing state is required for absence seizures, and switching to tonic firing rapidly halts absences. This approach should be useful for modulating other networks that have mode-dependent behaviors. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Entropy Based Detection of DDoS Attacks in Packet Switching Network Models

    Science.gov (United States)

    Lawniczak, Anna T.; Wu, Hao; di Stefano, Bruno

    Distributed denial-of-service (DDoS) attacks are network-wide attacks that cannot be detected or stopped easily. They affect “natural” spatio-temporal packet traffic patterns, i.e. “natural distributions” of packets passing through the routers. Thus, they affect “natural” information entropy profiles, a sort of “fingerprints”, of normal packet traffic. We study if by monitoring information entropy of packet traffic through selected routers one may detect DDoS attacks or anomalous packet traffic in packet switching network (PSN) models. Our simulations show that the considered DDoS attacks of “ping” type cause shifts in information entropy profiles of packet traffic monitored even at small sets of routers and that it is easier to detect these shifts if static routing is used instead of dynamic routing. Thus, network-wide monitoring of information entropy of packet traffic at properly selected routers may provide means for detecting DDoS attacks and other anomalous packet traffics.

  11. Collaborative Tracking Control of Dual Linear Switched Reluctance Machines Over Communication Network With Time Delays.

    Science.gov (United States)

    Qiu, Li; Shi, Yang; Pan, Jianfei; Zhang, Bo; Xu, Gang

    2017-12-01

    This paper investigates the collaborative tracking control for dual linear switched reluctance machines (LSRMs) over a communication network with random time delays. Considering the spatio-temporal constraint relationship of the dual LSRMs in complex industrial processes, the collaborative tracking control scheme is proposed based on the networked motion control method. The stability conditions and the controller design method for the networked dual LSRMs are obtained from the two motors relative position error by using Lyapunov theory and delay systems approach. Four different allocation schemes combined with two kinds of external control signals are applied onto the collaborative tracking control experiment platform of the dual LSRMs to validate the effectiveness of the proposed method. The maximum steady-state relative position error within 0.104 mm can be achieved under the constant absolute position reference input signal of 3 mm, and the maximum absolute relative position error within ±0.46 mm can be achieved under the sinusoidal reference of 8 mm amplitude and 0.2 Hz.

  12. Modeling Markov switching ARMA-GARCH neural networks models and an application to forecasting stock returns.

    Science.gov (United States)

    Bildirici, Melike; Ersin, Özgür

    2014-01-01

    The study has two aims. The first aim is to propose a family of nonlinear GARCH models that incorporate fractional integration and asymmetric power properties to MS-GARCH processes. The second purpose of the study is to augment the MS-GARCH type models with artificial neural networks to benefit from the universal approximation properties to achieve improved forecasting accuracy. Therefore, the proposed Markov-switching MS-ARMA-FIGARCH, APGARCH, and FIAPGARCH processes are further augmented with MLP, Recurrent NN, and Hybrid NN type neural networks. The MS-ARMA-GARCH family and MS-ARMA-GARCH-NN family are utilized for modeling the daily stock returns in an emerging market, the Istanbul Stock Index (ISE100). Forecast accuracy is evaluated in terms of MAE, MSE, and RMSE error criteria and Diebold-Mariano equal forecast accuracy tests. The results suggest that the fractionally integrated and asymmetric power counterparts of Gray's MS-GARCH model provided promising results, while the best results are obtained for their neural network based counterparts. Further, among the models analyzed, the models based on the Hybrid-MLP and Recurrent-NN, the MS-ARMA-FIAPGARCH-HybridMLP, and MS-ARMA-FIAPGARCH-RNN provided the best forecast performances over the baseline single regime GARCH models and further, over the Gray's MS-GARCH model. Therefore, the models are promising for various economic applications.

  13. Modeling Markov Switching ARMA-GARCH Neural Networks Models and an Application to Forecasting Stock Returns

    Directory of Open Access Journals (Sweden)

    Melike Bildirici

    2014-01-01

    Full Text Available The study has two aims. The first aim is to propose a family of nonlinear GARCH models that incorporate fractional integration and asymmetric power properties to MS-GARCH processes. The second purpose of the study is to augment the MS-GARCH type models with artificial neural networks to benefit from the universal approximation properties to achieve improved forecasting accuracy. Therefore, the proposed Markov-switching MS-ARMA-FIGARCH, APGARCH, and FIAPGARCH processes are further augmented with MLP, Recurrent NN, and Hybrid NN type neural networks. The MS-ARMA-GARCH family and MS-ARMA-GARCH-NN family are utilized for modeling the daily stock returns in an emerging market, the Istanbul Stock Index (ISE100. Forecast accuracy is evaluated in terms of MAE, MSE, and RMSE error criteria and Diebold-Mariano equal forecast accuracy tests. The results suggest that the fractionally integrated and asymmetric power counterparts of Gray’s MS-GARCH model provided promising results, while the best results are obtained for their neural network based counterparts. Further, among the models analyzed, the models based on the Hybrid-MLP and Recurrent-NN, the MS-ARMA-FIAPGARCH-HybridMLP, and MS-ARMA-FIAPGARCH-RNN provided the best forecast performances over the baseline single regime GARCH models and further, over the Gray’s MS-GARCH model. Therefore, the models are promising for various economic applications.

  14. H ∞ Cluster Synchronization for a Class of Neutral Complex Dynamical Networks with Markovian Switching

    Science.gov (United States)

    2014-01-01

    H ∞ cluster synchronization problem for a class of neutral complex dynamical networks (NCDNs) with Markovian switching is investigated in this paper. Both the retarded and neutral delays are considered to be interval mode dependent and time varying. The concept of H ∞ cluster synchronization is proposed to quantify the attenuation level of synchronization error dynamics against the exogenous disturbance of the NCDNs. Based on a novel Lyapunov functional, by employing some integral inequalities and the nature of convex combination, mode delay-range-dependent H ∞ cluster synchronization criteria are derived in the form of linear matrix inequalities which depend not only on the disturbance attenuation but also on the initial values of the NCDNs. Finally, numerical examples are given to demonstrate the feasibility and effectiveness of the proposed theoretical results. PMID:24892088

  15. User selective mode-forming remote switch in multi-mode fiber distributing networks using MIMO processing

    Science.gov (United States)

    Morizumi, Yuki; Kobayashi, Hirokazu; Iwashita, Katsushi

    2017-06-01

    A mode-forming remote switch in multi-mode fiber distributing networks has been proposed. It can transmit the desired data to the desired port by adjusting transmitter signals. Feasibilities of the proposed scheme are confirmed by switching sub-carrier BPSK signal to the selected port. A graded-index multi-mode fiber link whose output is divided into two ports by a mode-dependent optical coupler, is used as mode-division multiplexing network. Its channel matrix is obtained by using MIMO processing technologies. Amplitudes and phases of the data are adjusted according to the channel matrix. The data is successfully switched to the desired port. Also, wavelength independences are clarified.

  16. Tau can switch microtubule network organizations: from random networks to dynamic and stable bundles.

    Science.gov (United States)

    Prezel, Elea; Elie, Auréliane; Delaroche, Julie; Stoppin-Mellet, Virginie; Bosc, Christophe; Serre, Laurence; Fourest-Lieuvin, Anne; Andrieux, Annie; Vantard, Marylin; Arnal, Isabelle

    2017-11-22

    In neurons, microtubule networks alternate between single filaments and bundled arrays under the influence of effectors controlling their dynamics and organization. Tau is a microtubule bundler which stabilizes microtubules by stimulating growth and inhibiting shrinkage. The mechanisms by which tau organizes microtubule networks remain poorly understood. Here, we studied the self-organization of microtubules growing in the presence of tau isoforms and mutants. The results show that tau's ability to induce stable microtubule bundles requires two hexapeptides located in its microtubule-binding domain, and is modulated by its projection domain. Site-specific pseudo-phosphorylation of tau promotes distinct microtubule organizations: stable single microtubules, stable bundles or dynamic bundles. Disease-related tau mutations increase the formation of highly dynamic bundles. Finally, cryo-electron microscopy experiments indicate that tau and its variants similarly change the microtubule lattice structure by increasing both the protofilament number and lattice defects. Overall, our results uncover novel phospho-dependent mechanisms governing tau's ability to trigger microtubule organization and reveal that disease-related modifications of tau promote specific microtubule organizations which may have a deleterious impact during neurodegeneration. © 2017 by The American Society for Cell Biology.

  17. Prototype Packages for Managing and Animating Longitudinal Network Data: dynamicnetwork and rSoNIA

    Directory of Open Access Journals (Sweden)

    Skye Bender-deMoll

    2007-12-01

    Full Text Available Work with longitudinal network survey data and the dynamic network outputs of the statnet ERGMs has demonstrated the need for consistent frameworks and data structures for expressing, storing, and manipulating information about networks that change in time. Motivated by our requirements for exchanging data among researchers and various analysis and visualization processes, we have created an R package dynamicnetwork that builds upon previous work in the network, statnet and sna packages and provides a limited functional implementation. This paper discusses design issues and considerations, describes classes and forms of dynamic data, and works through several examples to demonstrate the utility of the package. The functionality of the rSoNIA package that uses dynamicnetwork to exchange data with the Social Network Image Animator (SoNIA software to create animated movies of changing networks from within R is also demonstrated.

  18. Two novel batch scheduling algorithms with insufficient wavelength converters in optical burst switching networks

    Science.gov (United States)

    Huang, Sheng; Pang, Hong-Feng; Li, Ling-Xia

    2013-03-01

    In optical burst switching networks, wavelength converters (WCs) of core nodes are used to decrease the burst loss rate. The implementation of the WCs is difficult in the current technology and the cost of WCs is high. So some core nodes may be configured insufficient WCs to reduce the cost in OBS networks. However, many data channel scheduling algorithms do not count the number of WCs and the performance of burst loss rate is not good in the condition of insufficient WCs. To overcome the defect, two novel batch scheduling algorithm with insufficiency of WC are proposed in this paper. The former algorithm improves the WCs' resource utilization probability to reduce the burst loss rate and the later algorithm saves the WCs' resource for the incoming bursts to use to improve the burst loss performance. The later algorithm can reduce more burst loss rate with the same number of WCs, compared with the other scheduling algorithms. The simulation results show that the later algorithm is more effective in reducing the burst loss rate with insufficient WCs.

  19. Wireless Relay Selection in Pocket Switched Networks Based on Spatial Regularity of Human Mobility.

    Science.gov (United States)

    Huang, Jianhui; Cheng, Xiuzhen; Bi, Jingping; Chen, Biao

    2016-01-18

    Pocket switched networks (PSNs) take advantage of human mobility to deliver data. Investigations on real-world trace data indicate that human mobility shows an obvious spatial regularity: a human being usually visits a few places at high frequencies. These most frequently visited places form the home of a node, which is exploited in this paper to design two HomE based Relay selectiOn (HERO) algorithms. Both algorithms input single data copy into the network at any time. In the basic HERO, only the first node encountered by the source and whose home overlaps a destination's home is selected as a relay while the enhanced HERO keeps finding more optimal relay that visits the destination's home with higher probability. The two proposed algorithms only require the relays to exchange the information of their home and/or the visiting frequencies to their home when two nodes meet. As a result, the information update is reduced and there is no global status information that needs to be maintained. This causes light loads on relays because of the low communication cost and storage requirements. Additionally, only simple operations are needed in the two proposed algorithms, resulting in little computation overhead at relays. At last, a theoretical analysis is performed on some key metrics and then the real-world based simulations indicate that the two HERO algorithms are efficient and effective through employing only one or a few relays.

  20. MUPBED: A Pan-European Prototype for Multi-Domain Research Networks

    DEFF Research Database (Denmark)

    Spaeth, Jan; Cavazzoni, Carlo; Foisel, Hans-Martin

    2009-01-01

    Integration and full interoperability are challenging areas of research in wide-area networks today. A European project, MUPBED, has recently concluded and achieved the main result of integrating and demonstrating technologies and network solutions that enable the operation of future European res...

  1. Resistive Switching Memory of TiO2 Nanowire Networks Grown on Ti Foil by a Single Hydrothermal Method

    Science.gov (United States)

    Xiao, Ming; Musselman, Kevin P.; Duley, Walter W.; Zhou, Norman Y.

    2017-04-01

    The resistive switching characteristics of TiO2 nanowire networks directly grown on Ti foil by a single-step hydrothermal technique are discussed in this paper. The Ti foil serves as the supply of Ti atoms for growth of the TiO2 nanowires, making the preparation straightforward. It also acts as a bottom electrode for the device. A top Al electrode was fabricated by e-beam evaporation process. The Al/TiO2 nanowire networks/Ti device fabricated in this way displayed a highly repeatable and electroforming-free bipolar resistive behavior with retention for more than 104 s and an OFF/ON ratio of approximately 70. The switching mechanism of this Al/TiO2 nanowire networks/Ti device is suggested to arise from the migration of oxygen vacancies under applied electric field. This provides a facile way to obtain metal oxide nanowire-based ReRAM device in the future.

  2. A network-flow based valve-switching aware binding algorithm for flow-based microfluidic biochips

    DEFF Research Database (Denmark)

    Tseng, Kai-Han; You, Sheng-Chi; Minhass, Wajid Hassan

    2013-01-01

    biochip needs more chip-integrated micro-valves, i.e., the basic unit of fluid-handling functionality, to manipulate the fluid flow for biochemical applications. Moreover, frequent switching of micro-valves results in decreased reliability. To minimize the valve-switching activities, we develop a network......Designs of flow-based microfluidic biochips are receiving much attention recently because they replace conventional biological automation paradigm and are able to integrate different biochemical analysis functions on a chip. However, as the design complexity increases, a flow-based microfluidic...

  3. Controller for the Power Converters of the O/OMOTOR Prototype Switched Reluctance Machine of the ACE2 Project; Controlador de los Convertidores Electronicos de Potencia de la Maquina Variable Prototipo O/OMOTOR del Proyecto ACE2

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, C.

    2006-12-19

    The ACE2 project deals with the development of a kynetic energy storage (KES) system for power peak shaving in high speed railway substations. This KES system consists in a double power converter which drives a switched reluctance machine (SRM) along with a flywheel operating in a wide speed range. This document presents from a technical point of view the features of the controller of the power converters for the U and UMOTOR SRM prototypes of that project. Hardware and software issues are treated in detail and the guide for the final user managing the KES module is introduced. (Author) 3 refs.

  4. NAVIGATING PROTOTYPING SPACES FOR CO-DESIGN OF ACTOR-NETWORKS

    DEFF Research Database (Denmark)

    Pedersen, Signe; Brodersen, Søsser

    2017-01-01

    In this article, we take up the challenge posed by Latour to map controversies and design things (socio-technical assemblies that address matters of concern) instead of designing products. By doing so, we draw attention to the role of the designer as a navigator of engagements with a number...... insulin more accessible to poor diabetes patients in India, we explore how designers navigate the design process, and design an actor-network (thing) that addresses matters of concern for all actors involved. We find that co-designing actor-networks to span flexible solutions entails navigating a number...

  5. A Novel QKD-based Secure Edge Router Architecture Design for Burst Confidentiality in Optical Burst Switched Networks

    Science.gov (United States)

    Balamurugan, A. M.; Sivasubramanian, A.

    2014-06-01

    The Optical Burst Switching (OBS) is an emergent result to the technology issue that could achieve a viable network in future. They have the ability to meet the bandwidth requisite of those applications that call for intensive bandwidth. The field of optical transmission has undergone numerous advancements and is still being researched mainly due to the fact that optical data transmission can be done at enormous speeds. The concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution and quality of service (QoS). This paper proposes a framework based on QKD based secure edge router architecture design to provide burst confidentiality. The QKD protocol offers high level of confidentiality as it is indestructible. The design architecture was implemented in FPGA using diverse models and the results were taken. The results show that the proposed model is suitable for real time secure routing applications of the Optical burst switched networks.

  6. Spatial Multiplexing of Atom-Photon Entanglement Sources using Feedforward Control and Switching Networks

    Science.gov (United States)

    Tian, Long; Xu, Zhongxiao; Chen, Lirong; Ge, Wei; Yuan, Haoxiang; Wen, Yafei; Wang, Shengzhi; Li, Shujing; Wang, Hai

    2017-09-01

    The light-matter quantum interface that can create quantum correlations or entanglement between a photon and one atomic collective excitation is a fundamental building block for a quantum repeater. The intrinsic limit is that the probability of preparing such nonclassical atom-photon correlations has to be kept low in order to suppress multiexcitation. To enhance this probability without introducing multiexcitation errors, a promising scheme is to apply multimode memories to the interface. Significant progress has been made in temporal, spectral, and spatial multiplexing memories, but the enhanced probability for generating the entangled atom-photon pair has not been experimentally realized. Here, by using six spin-wave-photon entanglement sources, a switching network, and feedforward control, we build a multiplexed light-matter interface and then demonstrate a ˜sixfold (˜fourfold ) probability increase in generating entangled atom-photon (photon-photon) pairs. The measured compositive Bell parameter for the multiplexed interface is 2.49 ±0.03 combined with a memory lifetime of up to ˜51 μ s .

  7. Artificial neural network based torque calculation of switched reluctance motor without locking the rotor

    Science.gov (United States)

    Kucuk, Fuat; Goto, Hiroki; Guo, Hai-Jiao; Ichinokura, Osamu

    2009-04-01

    Feedback of motor torque is required in most of switched reluctance (SR) motor applications in order to control torque and its ripple. An SR motor shows highly nonlinear property which does not allow calculating torque analytically. Torque can be directly measured by torque sensor, but it inevitably increases the cost and has to be properly mounted on the motor shaft. Instead of torque sensor, finite element analysis (FEA) may be employed for torque calculation. However, motor modeling and calculation takes relatively long time. The results of FEA may also differ from the actual results. The most convenient way seems to calculate torque from the measured values of rotor position, current, and flux linkage while locking the rotor at definite positions. However, this method needs an extra assembly to lock the rotor. In this study, a novel torque calculation based on artificial neural networks (ANNs) is presented. Magnetizing data are collected while a 6/4 SR motor is running. They need to be interpolated for torque calculation. ANN is very strong tool for data interpolation. ANN based torque estimation is verified on the 6/4 SR motor and is compared by FEA based torque estimation to show its validity.

  8. Investigative Data Mining Toolkit: A Software Prototype for Visualizing, Analyzing and Destabilizing Terrorist Networks

    Science.gov (United States)

    2006-12-01

    Community Structure in Very Large Networks, Physical Review E70, 066111 (2004) [25] M. Newman. A Measure of Betweenness Centrality based on Random...Fayz Ahmed, M. Alshehi, Hamza alghamdi and Ahmed alghamdi UA Flight 93: Zaid Jarrah, Ahmed alhaznawi, Saeed Alghmdi and Ahmed alnami Structural

  9. Prototype of a Mobile Social Network for Education Using Dynamic Web Service

    Science.gov (United States)

    Hoentsch, Sandra Costa Pinto; Carvalho, Felipe Oliveira; Santos, Luiz Marcus Monteiro de Almeida; Ribeiro, Admilson de Ribamar Lima

    2012-01-01

    This article presents the proposal of a social network site SocialNetLab that belongs to the Department of Computing-Federal University of Sergipe and which aims to locate and notify users of a nearby friend independently of the location technology available in the equipment through dynamic Web Service; to serve as a laboratory for research in…

  10. Bistability in a Metabolic Network Underpins the De Novo Evolution of Colony Switching in Pseudomonas fluorescens

    DEFF Research Database (Denmark)

    Gallie, Jenna; Libby, Eric; Bertels, Frederic

    2015-01-01

    in central metabolism (carB) generates such a striking phenotype. We show that colony switching is underpinned by ON/OFF expression of capsules consisting of a colanic acid-like polymer. We use molecular genetics, biochemical analyses, and experimental evolution to establish that capsule switching results......Phenotype switching is commonly observed in nature. This prevalence has allowed the elucidation of a number of underlying molecular mechanisms. However, little is known about how phenotypic switches arise and function in their early evolutionary stages. The first opportunity to provide empirical...... insight was delivered by an experiment in which populations of the bacterium Pseudomonas fluorescens SBW25 evolved, de novo, the ability to switch between two colony phenotypes. Here we unravel the molecular mechanism behind colony switching, revealing how a single nucleotide change in a gene enmeshed...

  11. Almost Sure Asymptotical Adaptive Synchronization for Neutral-Type Neural Networks with Stochastic Perturbation and Markovian Switching

    Directory of Open Access Journals (Sweden)

    Wuneng Zhou

    2014-01-01

    Full Text Available The problem of almost sure (a.s. asymptotic adaptive synchronization for neutral-type neural networks with stochastic perturbation and Markovian switching is researched. Firstly, we proposed a new criterion of a.s. asymptotic stability for a general neutral-type stochastic differential equation which extends the existing results. Secondly, based upon this stability criterion, by making use of Lyapunov functional method and designing an adaptive controller, we obtained a condition of a.s. asymptotic adaptive synchronization for neutral-type neural networks with stochastic perturbation and Markovian switching. The synchronization condition is expressed as linear matrix inequality which can be easily solved by Matlab. Finally, we introduced a numerical example to illustrate the effectiveness of the method and result obtained in this paper.

  12. Medium access control and hardware prototype designs for low-energy wireless sensor networks

    Energy Technology Data Exchange (ETDEWEB)

    Kohvakka, M.

    2009-07-01

    A Wireless Sensor Network (WSN) is an emerging technology consisting of small, cheap, and ultra-low energy sensor nodes, which cooperatively monitor physical quantities, actuate, and perform data processing tasks. A deployment may comprise thousands of randomly distributed autonomous nodes, which must self-configure and create a multi-hop network topology.This thesis focuses on low-energy WSNs targeting to long network lifetime. The main research problem is the combination of adaptive and scalable multi-hop networking with constrained energy budget, processing power, and communication bandwidth. The research problem is approached by energy-efficient protocols and low-power sensor node platforms. The main contribution of this thesis is an energy-efficient Medium Access Control (MAC) design for TUTWSN (Tampere University of Technology Wireless Sensor Network). The design comprises channel access and networking mechanisms, which specify data exchange, link synchronization, network self-configuration, and neighbor discovery operations. The second outcome are several low-power sensor node platforms, which have been designed and implemented to evaluate the performance of the MAC design and hardware components in real deployments. The third outcome are the performance models and analysis of several MAC designs including TUTWSN, IEEE 802.15.4, and the most essential research proposals.The results and conclusion of this Thesis indicate that it is possible to implement multi-hop WSNs in harsh and dynamic operation conditions with years of lifetime using current low-cost components and batteries. Energy analysis results indicate that the lowest energy consumption is achieved by using simple and high data-rate transceivers. It is also critical to minimize sleep mode power consumption of all components and to use accurate wake-up timers. However, the selection of components constitutes only a minor part of the solution, and an energy-efficient MAC layer design being able to

  13. Prototyping of chemical composition of complex crystals using method of neural networks

    Science.gov (United States)

    Blagin, A. V.; Nefedov, V. V.; Nefedova, N. A.

    2017-10-01

    The traditional methods of study of multi-component crystal heterojunction structures by means of X-ray diffractometry and electroscopy are expensive and complex. The present paper discusses the information technology based on the use of artificial neural networks for identification of the chemical composition of complex semiconductor structures. The obtained results allow supposing the successful use of this method for many multi-component systems.

  14. Cluster Synchronization of Stochastic Complex Networks with Markovian Switching and Time-Varying Delay via Impulsive Pinning Control

    Directory of Open Access Journals (Sweden)

    Xuan Zhou

    2014-01-01

    Full Text Available This paper studies the cluster synchronization of a kind of complex networks by means of impulsive pinning control scheme. These networks are subject to stochastic noise perturbations and Markovian switching, as well as internal and outer time-varying delays. Using the Lyapunov-Krasovskii functional, Itö’s formula, and some linear matrix inequalities (LMI, several novel sufficient conditions are obtained to guarantee the desired cluster synchronization. At the end of this writing, a numerical simulation is given to demonstrate the effectiveness of those theoretical results.

  15. Advances in integrated photonic circuits for packet-switched interconnection

    Science.gov (United States)

    Williams, Kevin A.; Stabile, Ripalta

    2014-03-01

    Sustained increases in capacity and connectivity are needed to overcome congestion in a range of broadband communication network nodes. Packet routing and switching in the electronic domain are leading to unsustainable energy- and bandwidth-densities, motivating research into hybrid solutions: optical switching engines are introduced for massive-bandwidth data transport while the electronic domain is clocked at more modest GHz rates to manage routing. Commercially-deployed optical switching engines using MEMS technologies are unwieldy and too slow to reconfigure for future packet-based networking. Optoelectronic packet-compliant switch technologies have been demonstrated as laboratory prototypes, but they have so far mostly used discretely pigtailed components, which are impractical for control plane development and product assembly. Integrated photonics has long held the promise of reduced hardware complexity and may be the critical step towards packet-compliant optical switching engines. Recently a number of laboratories world-wide have prototyped optical switching circuits using monolithic integration technology with up to several hundreds of integrated optical components per chip. Our own work has focused on multi-input to multi-output switching matrices. Recently we have demonstrated 8×8×8λ space and wavelength selective switches using gated cyclic routers and 16×16 broadband switching chips using monolithic multi-stage networks. We now operate these advanced circuits with custom control planes implemented with FPGAs to explore real time packet routing in multi-wavelength, multi-port test-beds. We review our contributions in the context of state of the art photonic integrated circuit technology and packet optical switching hardware demonstrations.

  16. Including 10-Gigabit-capable Passive Optical Network under End-to-End Generalized Multi-Protocol Label Switching Provisioned Quality of Service

    DEFF Research Database (Denmark)

    Brewka, Lukasz Jerzy; Gavler, Anders; Wessing, Henrik

    2012-01-01

    End-to-end quality of service provisioning is still a challenging task despite many years of research and development in this area. Considering a generalized multi-protocol label switching based core/metro network and resource reservation protocol capable home gateways, it is the access part...... of the network where quality of service signaling is bridged. This article proposes strategies for generalized multi-protocol label switching control over next emerging passive optical network standard, i.e., the 10-gigabit-capable passive optical network. Node management and resource allocation approaches...... are discussed, and possible issues are raised. The analysis shows that consideration of a 10-gigabit-capable passive optical network as a generalized multi-protocol label switching controlled domain is valid and may advance end-to-end quality of service provisioning for passive optical network based customers....

  17. Mobi-Sim: An Emulation and Prototyping Platform for Protocols Validation of Mobile Wireless Sensors Networks

    Directory of Open Access Journals (Sweden)

    Omina Mezghani

    2017-01-01

    Full Text Available The objective of this paper is to provide a new simulator framework for mobile WSN that emulate a sensor node at a laptop i.e. the laptop will model and replace a sensor node within a network. This platform can implement different WSN routing protocols to simulate and validate new developed protocols in terms of energy consumption, loss packets rate, delivery ratio, mobility support, connectivity and exchanged messages number in real time. To evaluate the performance of Mobi-Sim, we implement into it two popular protocols (LEACH-M and LEACH sink-mobile and compare its results to TOSSIM. Then, we propose another routing protocol based on clustering that we compare it to LEACH-M.

  18. High-dimensional neural network potentials for metal surfaces: A prototype study for copper

    Science.gov (United States)

    Artrith, Nongnuch; Behler, Jörg

    2012-01-01

    The atomic environments at metal surfaces differ strongly from the bulk, and, in particular, in case of reconstructions or imperfections at “real surfaces,” very complicated atomic configurations can be present. This structural complexity poses a significant challenge for the development of accurate interatomic potentials suitable for large-scale molecular dynamics simulations. In recent years, artificial neural networks (NN) have become a promising new method for the construction of potential-energy surfaces for difficult systems. In the present work, we explore the applicability of such high-dimensional NN potentials to metal surfaces using copper as a benchmark system. A detailed analysis of the properties of bulk copper and of a wide range of surface structures shows that NN potentials can provide results of almost density functional theory (DFT) quality at a small fraction of the computational costs.

  19. Introduction to Optical Burst Switching

    OpenAIRE

    KERNÁCS János; Szilágyi, Szabolcs

    2010-01-01

    Optical Burst Switching (OBS) isconsidered a popular switching paradigm for therealization of all-optical networks due to the balance itoffers between the coarse-grained Optical CircuitSwitching (OSC) and fine-grained Optical PacketSwitching (OPS). Given that the data are switched allopticallyat the burst level, Optical Burst Switchingcombines the transparency of Optical CircuitSwitching with the benefits of statistical multiplexingin Optical Packet Switching.

  20. Neural networks-based operational prototype for flash flood forecasting: application to Liane flash floods (France

    Directory of Open Access Journals (Sweden)

    Bertin Dominique

    2016-01-01

    Full Text Available The Liane River is a small costal river, famous for its floods, which can affect the city of Boulogne-sur-Mer. Due to the complexity of land cover and hydrologic processes, a black-box non-linear modelling was chosen using neural networks. The multilayer perceptron model, known for its property of universal approximation is thus chosen. Four models were designed, each one for one forecasting horizon using rainfall forecasts: 24h, 12h, 6h, 3h. The desired output of the model is original: it represents the maximal value of the water level respectively 24h, 12h, 6h, 3h ahead. Working with best forecasts of rain (the observed ones during the event in the past, on the major flood of the database in test set, the model provides excellent forecasts. Nash criteria calculated for the four lead times are 0.98 (3h, 0.97 (6h, 0.91 (12h, 0.89 (24h. Designed models were thus estimated as efficient enough to be implemented in a specific tool devoted to real time operational use. The software tool is described hereafter: designed in Java, it presents a friendly interface allowing applying various scenarios of future rainfalls, and a graphical visualization of the predicted maximum water levels and their associated real time observed values.

  1. Original models of NGN/IMS-networks surrounded by circuit-switched systems

    OpenAIRE

    Kulikov, Nikolay

    2014-01-01

    On obtaining of the Alexander Graham Bell a patent for invention of the telephone in 1987, the communication system consistently has gone through several evolutionary stages: from analog lines and manual switches to video telephony and IMS architecture. Each of the stages can be described by specific switching systems, data transmission systems and types of transmitted information. After implementation of such solution, it is possible to create a number of access nodes in the Operators IMS-ne...

  2. Experimental Demonstration of Multidimensional Switching Nodes for All-Optical Data Center Networks

    DEFF Research Database (Denmark)

    Kamchevska, Valerija; Medhin, Ashenafi Kiros; Da Ros, Francesco

    2016-01-01

    This paper reports on a novel ring-based data center architecture composed of multidimensional switching nodes. The nodes are interconnected with multicore fibers and can provide switching in three different physical, hierarchically overlaid dimensions (space, wavelength, and time). The proposed...... by increasing the transmission capacity to 1 Tbit/s/core equivalent to 7 Tbit/s total throughput in a single seven-core multicore fiber. The error-free performance (BER centers and accommodate...

  3. Performance Analysis of Particle Swarm Optimization Based Routing Algorithm in Optical Burst Switching Networks

    Science.gov (United States)

    Hou, Rui; Yu, Junle

    2011-12-01

    Optical burst switching (OBS) has been regarded as the next generation optical switching technology. In this paper, the routing problem based on particle swarm optimization (PSO) algorithm in OBS has been studies and analyzed. Simulation results indicate that, the PSO based routing algorithm will optimal than the conversional shortest path first algorithm in space cost and calculation cost. Conclusions have certain theoretical significances for the improvement of OBS routing protocols.

  4. Enterasys Networks delivers standards-based 10-Gigabit ethernet modules for its Enterasys X-Pedition Routers and Enterasys Matrix Switches

    CERN Multimedia

    2002-01-01

    Enterasys Networks Inc. has announced new 10-Gigabit Ethernet modules for the Enterasys X-Pedition ER16 routers and Enterasys Matrix E1 OAS (Optical Access Switch). The addition of 10-Gigabit Ethernet technology enables the Enterasys X-Pedition ER16 enables real-time delivery of high-bandwidth, advanced applications across local area network (LAN), wide area network (WAN) and metropolitan area network (MAN) environments (1/2 page).

  5. Collaborative Prototyping

    DEFF Research Database (Denmark)

    Bogers, Marcel; Horst, Willem

    2014-01-01

    This paper presents an inductive study that shows how collaborative prototyping across functional, hierarchical, and organizational boundaries can improve the overall prototyping process. Our combined action research and case study approach provides new insights into how collaborative prototyping...... can provide a platform for prototype-driven problem solving in early new product development (NPD). Our findings have important implications for how to facilitate multistakeholder collaboration in prototyping and problem solving, and more generally for how to organize collaborative and open innovation...... processes. Our analysis reveals two levels of prototyping. Besides the more formal managerial level, we identify the informal designer level, where the actual practice of prototyping takes place. On this level, collaborative prototyping transforms the act of prototyping from an activity belonging...

  6. Green Networking in Cellular HetNets: A Unified Radio Resource Management Framework with Base Station ON/OFF Switching

    KAUST Repository

    Ghazzai, Hakim

    2016-12-07

    In this paper, the problem of energy efficiency in cellular heterogeneous networks (HetNets) is investigated using radio resource and power management combined with the base station (BS) ON/OFF switching. The objective is to minimize the total power consumption of the network while satisfying the quality of service (QoS) requirements of each connected user. We consider the case of co-existing macrocell BS, small cell BSs, and private femtocell access points (FAPs). Three different network scenarios are investigated, depending on the status of the FAPs, i.e., HetNets without FAPs, HetNets with closed FAPs, and HetNets with semi-closed FAPs. A unified framework is proposed to simultaneously allocate spectrum resources to users in an energy efficient manner and switch off redundant small cell BSs. The high complexity dual decomposition technique is employed to achieve optimal solutions for the problem. A low complexity iterative algorithm is also proposed and its performances are compared to those of the optimal technique. The particularly interesting case of semi-closed FAPs, in which the FAPs accept to serve external users, achieves the highest energy efficiency due to increased degrees of freedom. In this paper, a cooperation scheme between FAPs and mobile operator is also investigated. The incentives for FAPs, e.g., renewable energy sharing and roaming prices, enabling cooperation are discussed to be considered as a useful guideline for inter-operator agreements.

  7. Architectural prototyping

    DEFF Research Database (Denmark)

    Bardram, Jakob Eyvind; Christensen, Henrik Bærbak; Hansen, Klaus Marius

    2004-01-01

    A major part of software architecture design is learning how specific architectural designs balance the concerns of stakeholders. We explore the notion of "architectural prototypes", correspondingly architectural prototyping, as a means of using executable prototypes to investigate stakeholders......' concerns with respect to a system under development. An architectural prototype is primarily a learning and communication vehicle used to explore and experiment with alternative architectural styles, features, and patterns in order to balance different architectural qualities. The use of architectural...... prototypes in the development process is discussed, and we argue that such prototypes can play a role throughout the entire process. The use of architectural prototypes is illustrated by three distinct cases of creating software systems. We argue that architectural prototyping can provide key insights...

  8. Architectural Prototyping

    DEFF Research Database (Denmark)

    Bardram, Jakob; Christensen, Henrik Bærbak; Hansen, Klaus Marius

    2004-01-01

    A major part of software architecture design is learning how specific architectural designs balance the concerns of stakeholders. We explore the notion of "architectural prototypes", correspondingly architectural prototyping, as a means of using executable prototypes to investigate stakeholders......' concerns with respect to a system under development. An architectural prototype is primarily a learning and communication vehicle used to explore and experiment with alternative architectural styles, features, and patterns in order to balance different architectural qualities. The use of architectural...... prototypes in the development process is discussed, and we argue that such prototypes can play a role throughout the entire process. The use of architectural prototypes is illustrated by three distinct cases of creating software systems. We argue that architectural prototyping can provide key insights...

  9. NEBULAS A High Performance Data-Driven Event-Building Architecture based on an Asynchronous Self-Routing Packet-Switching Network

    CERN Multimedia

    Costa, M; Letheren, M; Djidi, K; Gustafsson, L; Lazraq, T; Minerskjold, M; Tenhunen, H; Manabe, A; Nomachi, M; Watase, Y

    2002-01-01

    RD31 : The project is evaluating a new approach to event building for level-two and level-three processor farms at high rate experiments. It is based on the use of commercial switching fabrics to replace the traditional bus-based architectures used in most previous data acquisition sytems. Switching fabrics permit the construction of parallel, expandable, hardware-driven event builders that can deliver higher aggregate throughput than the bus-based architectures. A standard industrial switching fabric technology is being evaluated. It is based on Asynchronous Transfer Mode (ATM) packet-switching network technology. Commercial, expandable ATM switching fabrics and processor interfaces, now being developed for the future Broadband ISDN infrastructure, could form the basis of an implementation. The goals of the project are to demonstrate the viability of this approach, to evaluate the trade-offs involved in make versus buy options, to study the interfacing of the physics frontend data buffers to such a fabric, a...

  10. Controlled retransmission scheme for prioritized burst segmentation to support quality-of-service in optical burst switching networks

    Science.gov (United States)

    Hou, Rui; He, Tingting; Mao, Tengyue

    2012-10-01

    In optical burst switching (OBS) networks, burst contentions in OBS core nodes may cause data loss. To reduce this data loss, a retransmission scheme has been applied. However, uncontrolled retransmission may significantly increase network load and data loss probability, thus defeating the retransmission purpose. In addition, in a priority traffic existing OBS network, OBS nodes may apply different retransmission mechanisms to priority bursts for quality-of-service (QoS) support. We present a controlled retransmission scheme for prioritized burst segmentation to support QoS in OBS networks. Different from previous work in the literature, we set a different value to retransmission probability at each contention and propose a retransmission analytical model for a burst segmentation contention resolution scheme. In addition, we apply the proposed retransmission scheme to the prioritized burst segmentation for QoS support. We take into account the load at each link due to both the fresh and the retransmitted traffic and calculate the path-blocking probability and the byte loss probability for high-priority and low-priority bursts to evaluate the network performance. An extensive simulation is proposed to validate our analytical model.

  11. Fault Detection and Location by Static Switches in Microgrids Using Wavelet Transform and Adaptive Network-Based Fuzzy Inference System

    Directory of Open Access Journals (Sweden)

    Ying-Yi Hong

    2014-04-01

    Full Text Available Microgrids are a highly efficient means of embedding distributed generation sources in a power system. However, if a fault occurs inside or outside the microgrid, the microgrid should be immediately disconnected from the main grid using a static switch installed at the secondary side of the main transformer near the point of common coupling (PCC. The static switch should have a reliable module implemented in a chip to detect/locate the fault and activate the breaker to open the circuit immediately. This paper proposes a novel approach to design this module in a static switch using the discrete wavelet transform (DWT and adaptive network-based fuzzy inference system (ANFIS. The wavelet coefficient of the fault voltage and the inference results of ANFIS with the wavelet energy of the fault current at the secondary side of the main transformer determine the control action (open or close of a static switch. The ANFIS identifies the faulty zones inside or outside the microgrid. The proposed method is applied to the first outdoor microgrid test bed in Taiwan, with a generation capacity of 360.5 kW. This microgrid test bed is studied using the real-time simulator eMegaSim developed by Opal-RT Technology Inc. (Montreal, QC, Canada. The proposed method based on DWT and ANFIS is implemented in a field programmable gate array (FPGA by using the Xilinx System Generator. Simulation results reveal that the proposed method is efficient and applicable in the real-time control environment of a power system.

  12. A programming environment to control switching networks based on STC104 packet routing chip

    Science.gov (United States)

    Legrand, I. C.; Schwendicke, U.; Leich, H.; Medinnis, M.; Koehler, A.; Wegner, P.; Sulanke, K.; Dippel, R.; Gellrich, A.

    1997-02-01

    The software environment used to control a large switching architecture based on SGS-Thomson STC104 (an asynchronous 32-way dynamic packet routing chip) is presented. We are evaluating this switching technology for large scale, real-time parallel systems. A Graphical User Interface (GUI) written as a multi-thread application in Java allows to set the switch configuration and to continuously monitor the state of each link. This GUI connects to a multi-thread server via TCP/IP sockets. The server is running on a PC-Linux system and implements the virtual channel protocol in communicating with the STC104 switching units using the Data Strobe link or the VME bus. Linux I/O drivers to control the Data Strobe link parallel adaptor (STC101) were developed. For each client the server creates a new thread and allocates a new socket for communications. The Java code of the GUI may be transferred to any client using the http protocol providing a user friendly interface to the system with real-time monitoring which is also platform independent.

  13. Prototyping Practice

    DEFF Research Database (Denmark)

    Ramsgaard Thomsen, Mette; Tamke, Martin

    2015-01-01

    This paper examines the role of the prototyping in digital architecture. During the past decade, a new research field has emerged exploring the digital technology’s impact on the way we think, design and build our environment. In this practice the prototype, the pavilion, installation...... or demonstrator, has become a shared research tool. This paper asks how this practice has formed by tracing the different roles of the prototype from ideation and design, to analysis and evaluation. Taking point of departure in CITA’s own prototyping practice, we explore the relationships between physical...... and digital prototyping as a particular means of validation and verification. Here, a breadth of physical prototypes take on varying roles, in turn informing, testing and proving the research enquiry. The paper addresses how we can differentiate between these modes of prototyping and how....

  14. How to Enhance the Efficiency of Loss-Less Optical Burst Switching Networks with the Streamline Effect

    Directory of Open Access Journals (Sweden)

    Milos Kozak

    2015-01-01

    Full Text Available With the ongoing steady traffic increase in the Internet, the wavelength usage of the supporting optical networks is a critical network efficiency parameter. Therefore, this paper suggests a way how to efficiently and economically achieve this goal in the context of optical burst switching, a very promising technology that has been proposed to overcome the shortcomings of conventional WDM deployment, such as lack of fine bandwidth granularity in wavelength routing and electronic speed bottlenecks in the presence of bursty traffic. In order to mitigate the burst loss and achieve high network efficiency we adapt the loss-less paradigm defined by Coutelen et al. (2010, i.e., the CAROBS framework. In classical OBS networks, the streamline effect ensures a very low level of contention, i.e., efficient transmission, hence we define a routing guided only by the streamline effect. The resulting routing problem is formulated as an optimization model which is solved using a decomposition technique to increase the scalability of the solution process.

  15. Estimation of the Required Modeling Depth for the Simulation of Cable Switching in a Cable-based Network

    DEFF Research Database (Denmark)

    Silva, Filipe Faria Da; Bak, Claus Leth; Balle Holst, Per

    2012-01-01

    . The simulation of electromagnetic transients in cable-based networks requires larger computational effort than in an equivalent overhead-line (OHL)-based network. Therefore, the method is demonstrated for the former, with the cases of OHL-based networks and hybrid cable-OHL networks addressed in a future paper......The simulation of an electromagnetic transient is only as good as the model's data and the level of detail put into the modeling. One parameter with influence in the results is the size of the modeling of the area around the switched-on line. If the area is too small, the results are inaccurate....... If the area is too large, the simulation requires a long period of time and numerical problems are more likely to exist. This paper proposes a method that can be used to estimate the depth of the modeling area using the grid layout, which can be obtained directly from a PSS/E file, or equivalent...

  16. Performance Tradeoffs and Hierarchical Designs of Distributed Packet-Switching Communication Networks,

    Science.gov (United States)

    1979-09-01

    exss budge. invested in order to make the dela.y finite We shall noiA consider in detail the case of one-dimensional Lentralized systems, in which the...Switching Net- works," IEEE Transaction on Communi(’aton I’chnologv, Vol. COM-19, pp. 256-260, June 1971. [131 Metcalfe, R.M., and David R. Boggs, "litheinet

  17. Pinning dynamic systems of networks with Markovian switching couplings and controller-node set

    OpenAIRE

    Han, Yujuan; Lu, Wenlian; Li, Zhe; Chen, Tianping

    2014-01-01

    In this paper, we study pinning control problem of coupled dynamical systems with stochastically switching couplings and stochastically selected controller-node set. Here, the coupling matrices and the controller-node sets change with time, induced by a continuous-time Markovian chain. By constructing Lyapunov functions, we establish tractable sufficient conditions for exponentially stability of the coupled system. Two scenarios are considered here. First, we prove that if each subsystem in t...

  18. Shape-dependent control of cell growth, differentiation, and apoptosis: switching between attractors in cell regulatory networks

    Science.gov (United States)

    Huang, S.; Ingber, D. E.

    2000-01-01

    Development of characteristic tissue patterns requires that individual cells be switched locally between different phenotypes or "fates;" while one cell may proliferate, its neighbors may differentiate or die. Recent studies have revealed that local switching between these different gene programs is controlled through interplay between soluble growth factors, insoluble extracellular matrix molecules, and mechanical forces which produce cell shape distortion. Although the precise molecular basis remains unknown, shape-dependent control of cell growth and function appears to be mediated by tension-dependent changes in the actin cytoskeleton. However, the question remains: how can a generalized physical stimulus, such as cell distortion, activate the same set of genes and signaling proteins that are triggered by molecules which bind to specific cell surface receptors. In this article, we use computer simulations based on dynamic Boolean networks to show that the different cell fates that a particular cell can exhibit may represent a preprogrammed set of common end programs or "attractors" which self-organize within the cell's regulatory networks. In this type of dynamic network model of information processing, generalized stimuli (e.g., mechanical forces) and specific molecular cues elicit signals which follow different trajectories, but eventually converge onto one of a small set of common end programs (growth, quiescence, differentiation, apoptosis, etc.). In other words, if cells use this type of information processing system, then control of cell function would involve selection of preexisting (latent) behavioral modes of the cell, rather than instruction by specific binding molecules. Importantly, the results of the computer simulation closely mimic experimental data obtained with living endothelial cells. The major implication of this finding is that current methods used for analysis of cell function that rely on characterization of linear signaling pathways or

  19. Solution Prototype

    DEFF Research Database (Denmark)

    Efeoglu, Arkin; Møller, Charles; Serie, Michel

    2013-01-01

    This paper outlines an artifact building and evaluation proposal. Design Science Research (DSR) studies usually consider encapsulated artifact that have relationships with other artifacts. The solution prototype as a composed artifact demands for a more comprehensive consideration in its systematic...... environment. The solution prototype that is composed from blending product and service prototype has particular impacts on the dualism of DSR’s “Build” and “Evaluate”. Since the mix between product and service prototyping can be varied, there is a demand for a more agile and iterative framework. Van de Ven...

  20. Prototyping Revisited

    DEFF Research Database (Denmark)

    Hansen, Poul H. Kyvsgård; Hansen, Svend Aage; Hansen, Erik

    2006-01-01

    Until now, prototyping has been developing as a technological discipline. In so it has proven to be a strong means to test specific solutions or physical designs before the launch of a product. The results have been reduced development time and improvement of quality in a broad sense. There are......, however, indications that we should review our perception of prototypes to be broader and to view our application of prototypes in a broader organizational view. This paper presents an initial and explorative review of the changing role of prototypes in product development....

  1. Preclusion of switch behavior in reaction networks with mass-action kinetics

    DEFF Research Database (Denmark)

    Feliu, Elisenda; Wiuf, C.

    2012-01-01

    consists of components of the species formation rate function and a maximal set of independent conservation laws. The determinant of the function is a polynomial in the species concentrations and the rate constants (linear in the latter) and its coefficients are fully determined. The criterion also......We study networks taken with mass-action kinetics and provide a Jacobian criterion that applies to an arbitrary network to preclude the existence of multiple positive steady states within any stoichiometric class for any choice of rate constants. We are concerned with the characterization...... of injective networks, that is, networks for which the species formation rate function is injective in the interior of the positive orthant within each stoichiometric class. We show that a network is injective if and only if the determinant of the Jacobian of a certain function does not vanish. The function...

  2. Performance improvement of switched-based interference mitigation for channel assignment in over-loaded small-cell networks

    KAUST Repository

    Gaaloul, Fakhreddine

    2013-05-01

    This paper proposes adequate methods to improve the interference mitigation capability of a recently investigated switched-based interference reduction scheme for single downlink channel assignment in over-loaded small-cell networks. The model assumes that the available orthogonal channels for small cells are distributed among access points in close vicinity, where each access point knows its allocated channels a priori. Each cell has a single antenna, employs the open access strategy, and can reuse its allocated channels simultaneously, while scheduling concurrent service requests. Moreover, the access points can not coordinate their transmissions, and can receive limited feedback from active users. The paper presents low-complexity schemes to identify a suitable channel to serve the scheduled user by maintaining the interference power level within a tolerable range. They attempt to either complement the switched-based scheme by minimum interference channel selection or adopt different interference thresholds on available channels, while reducing the channel examination load. The optimal thresholds for interference mitigation at the desired receive station are quantified for various performance criteria. The performance and processing load of the proposed schemes are obtained analytically, and then compared to those of the single-threshold scheme via numerical and simulation results. © 2002-2012 IEEE.

  3. Restraint Method of Voltage Total Harmonic Distortion in Distribution Network by Power Conditioner Systems using Measured Data from IT Switches

    Science.gov (United States)

    Kawasaki, Shoji; Shimoda, Kazuki; Tanaka, Motohiro; Taoka, Hisao; Matsuki, Junya; Hayashi, Yasuhiro

    Recently, the amount of distributed generation (DG) such as photovoltaic system and wind power generator system installed in a distribution system has been increasing because of reduction of the effects on the environment. However, the harmonic troubles in the distribution system are apprehended in the background of the increase of connection of DGs through the inverters and the spread of power electronics equipment. In this paper, the authors propose a restraint method of voltage total harmonic distortion (THD) in a whole distribution network by active filter (AF) operation of plural power conditioner systems (PCS). Moreover, the authors propose a determination method of the optimal gain of AF operation so as to minimize the maximum value of voltage THD in the distribution network by the real-time feedback control with measured data from the information technology (IT) switches. In order to verify the validity of the proposed method, the numerical calculations are carried out by using an analytical model of distribution network interconnected DGs with PCS.

  4. Finite-Time Nonfragile Synchronization of Stochastic Complex Dynamical Networks with Semi-Markov Switching Outer Coupling

    Directory of Open Access Journals (Sweden)

    Rathinasamy Sakthivel

    2018-01-01

    Full Text Available The problem of robust nonfragile synchronization is investigated in this paper for a class of complex dynamical networks subject to semi-Markov jumping outer coupling, time-varying coupling delay, randomly occurring gain variation, and stochastic noise over a desired finite-time interval. In particular, the network topology is assumed to follow a semi-Markov process such that it may switch from one to another at different instants. In this paper, the random gain variation is represented by a stochastic variable that is assumed to satisfy the Bernoulli distribution with white sequences. Based on these hypotheses and the Lyapunov-Krasovskii stability theory, a new finite-time stochastic synchronization criterion is established for the considered network in terms of linear matrix inequalities. Moreover, the control design parameters that guarantee the required criterion are computed by solving a set of linear matrix inequality constraints. An illustrative example is finally given to show the effectiveness and advantages of the developed analytical results.

  5. Safety and function of a prototype microprocessor-controlled knee prosthesis for low active transfemoral amputees switching from a mechanic knee prosthesis: a pilot study.

    Science.gov (United States)

    Hasenoehrl, Timothy; Schmalz, Thomas; Windhager, Reinhard; Domayer, Stephan; Dana, Sara; Ambrozy, Clemens; Palma, Stefano; Crevenna, Richard

    2018-02-01

    Aim of this pilot study was to assess safety and functioning of a microprocessor-controlled knee prosthesis (MPK) after a short familiarization time and no structured physical therapy. Five elderly, low-active transfemoral amputees who were fitted with a standard non-microprocessor controlled knee prosthesis (NMPK) performed a baseline measurement consisting of a 3 D gait analysis, functional tests and questionnaires. The first follow-up consisted of the same test procedure and was performed with the MPK after 4 to 6 weeks of familiarization. After being refitted to their standard NMPK again, the subjects undertook the second follow-up which consisted of solely questionnaires 4 weeks later. Questionnaires and functional tests showed an increase in the perception of safety. Moreover, gait analysis revealed more physiologic knee and hip extension/flexion patterns when using the MPK. Our results showed that although the Genium with Cenior-Leg ruleset-MPK (GCL-MPK) might help to improve several safety-related outcomes as well as gait biomechanics the functional potential of the GCL-MPK may have been limited without specific training and a sufficient acclimation period. Implications for Rehabilitation Elderly transfemoral amputees are often limited in their activity by safety issues as well as insufficient functioning regarding the non microprocessor-controlled knee prostheses (NMPK), thing that could be eliminated with the use of suitable microprocessor-controlled prostheses (MPK). The safety and functioning of a prototype MPK (GCL-MPK) specifically designed for the needs of older and low-active transfemoral amputees was assessed in this pilot study. The GCL-MPK showed indicators of increased safety and more natural walking patterns in older and low-active transfemoral amputees in comparison to the standard NMPK already after a short acclimatisation time and no structured physical therapy. Regarding functional performance it seems as if providing older and low

  6. Synchronization of a Class of Switched Neural Networks with Time-Varying Delays via Nonlinear Feedback Control.

    Science.gov (United States)

    Wang, Leimin; Shen, Yi; Zhang, Guodong

    2016-10-01

    This paper is concerned with the synchronization problem for a class of switched neural networks (SNNs) with time-varying delays. First, a new crucial lemma which includes and extends the classical exponential stability theorem is constructed. Then by using the lemma, new algebraic criteria of ψ -type synchronization (synchronization with general decay rate) for SNNs are established via the designed nonlinear feedback control. The ψ -type synchronization which is in a general framework is obtained by introducing a ψ -type function. It contains exponential synchronization, polynomial synchronization, and other synchronization as its special cases. The results of this paper are general, and they also complement and extend some previous results. Finally, numerical simulations are carried out to demonstrate the effectiveness of the obtained results.

  7. Measurement of Mobile Switching Centres Throughput in GSM Network Integrating Sliding Window Algorithm with a Single Server Finite Queuing Model

    Directory of Open Access Journals (Sweden)

    Dinaker Babu Bollini

    2016-01-01

    Full Text Available The sliding window algorithm proposed for determining an optimal sliding window does not consider the waiting times of call setup requests of a mobile station in queue at a Mobile Switching Centre (MSC in the Global System for Mobile (GSM Communication Network. This study proposes a model integrating the sliding window algorithm with a single server finite queuing model, referred to as integrated model for measurement of realistic throughput of a MSC considering the waiting times of call setup requests. It assumes that a MSC can process one call setup request at a time. It is useful in determining an optimal sliding window size that maximizes the realistic throughput of a MSC. Though the model assumes that a MSC can process one call setup request at a time, its scope can be extended for measuring the realistic throughput of a MSC that can process multiple call setup requests at a time.

  8. Localised polymer networks in chiral nematic liquid crystals for high speed photonic switching

    Energy Technology Data Exchange (ETDEWEB)

    Tartan, Chloe C., E-mail: chloe.tartan@eng.ox.ac.uk, E-mail: steve.elston@eng.ox.ac.uk; Salter, Patrick S.; Booth, Martin J.; Morris, Stephen M.; Elston, Steve J., E-mail: chloe.tartan@eng.ox.ac.uk, E-mail: steve.elston@eng.ox.ac.uk [Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ (United Kingdom)

    2016-05-14

    Self-assembled periodic structures based upon chiral liquid crystalline materials have significant potential in the field of photonics ranging from fast-switching optoelectronic devices to low-threshold lasers. The flexoelectro-optic effect, which is observed in chiral nematic liquid crystals (LCs) when an electric field is applied perpendicular to the helical axis, has significant potential as it exhibits analogue switching in 10–100 μs. However, the major technological barrier that prohibits the commercial realisation of this electro-optic effect is the requirement of a uniform, in-plane alignment of the helix axis between glass substrates. Here, it is shown that periodic polymer structures engineered in the nematic phase of a chiral nematic LC device using direct laser writing can result in the spontaneous formation of the necessary uniform lying helix (ULH) state. Specifically, two-photon polymerization is used in conjunction with a spatial light modulator so as to correct for aberrations introduced by the bounding glass substrates enabling the polymer structures to be fabricated directly into the device. The ULH state appears to be stable in the absence of an externally applied electric field, and the optimum contrast between the bright and dark states is obtained using polymer structures that have periodicities of the order of the device thickness.

  9. Sucrose-based fabrication of 3D-networked, cylindrical microfluidic channels for rapid prototyping of lab-on-a-chip and vaso-mimetic devices.

    Science.gov (United States)

    Lee, Jiwon; Paek, Jungwook; Kim, Jaeyoun

    2012-08-07

    We present a new fabrication scheme for 3D-networked, cylindrical microfluidic (MF) channels based on shaping, bonding, and assembly of sucrose fibers. It is a simple, cleanroom-free, and environment-friendly method, ideal for rapid prototyping of lab-on-a-chip devices. Despite its simplicity, it can realize complex 3D MF channel architectures such as cylindrical tapers, internal loops, end-to-side junctions, tapered junctions, and stenosis. The last two will be of special use for realizing vaso-mimetic MF structures. It also enables molding with polymers incompatible with high-temperature processing.

  10. A receiver-initiated WDM multicast tree construction protocol to support IP dense mode multicast routing in all-optical Lambda-switched networks

    NARCIS (Netherlands)

    Niemegeers, I.G.M.M.; Salvador, M.R.; Heemstra de Groot, S.M.; Dey, D.

    We describe a source-rooted WDM multicast tree construction protocol to support IP dense mode multicast routing protocols in all-optical lambda-switched networks. Using a receiver-initiated approach, the protocol relies on a mechanism that collects information on the capabilities of WDM nodes. This

  11. On-board closed-loop congestion control for satellite based packet switching networks

    Science.gov (United States)

    Chu, Pong P.; Ivancic, William D.; Kim, Heechul

    1993-01-01

    NASA LeRC is currently investigating a satellite architecture that incorporates on-board packet switching capability. Because of the statistical nature of packet switching, arrival traffic may fluctuate and thus it is necessary to integrate congestion control mechanism as part of the on-board processing unit. This study focuses on the closed-loop reactive control. We investigate the impact of the long propagation delay on the performance and propose a scheme to overcome the problem. The scheme uses a global feedback signal to regulate the packet arrival rate of ground stations. In this scheme, the satellite continuously broadcasts the status of its output buffer and the ground stations respond by selectively discarding packets or by tagging the excessive packets as low-priority. The two schemes are evaluated by theoretical queuing analysis and simulation. The former is used to analyze the simplified model and to determine the basic trends and bounds, and the later is used to assess the performance of a more realistic system and to evaluate the effectiveness of more sophisticated control schemes. The results show that the long propagation delay makes the closed-loop congestion control less responsive. The broadcasted information can only be used to extract statistical information. The discarding scheme needs carefully-chosen status information and reduction function, and normally requires a significant amount of ground discarding to reduce the on-board packet loss probability. The tagging scheme is more effective since it tolerates more uncertainties and allows a larger margin of error in status information. It can protect the high-priority packets from excessive loss and fully utilize the downlink bandwidth at the same time.

  12. Fault Tolerant Mechanism for Multimedia Flows in Wireless Ad Hoc Networks Based on Fast Switching Paths

    Directory of Open Access Journals (Sweden)

    Juan R. Diaz

    2014-01-01

    Full Text Available Multimedia traffic can be forwarded through a wireless ad hoc network using the available resources of the nodes. Several models and protocols have been designed in order to organize and arrange the nodes to improve transmissions along the network. We use a cluster-based framework, called MWAHCA architecture, which optimizes multimedia transmissions over a wireless ad hoc network. It was proposed by us in a previous research work. This architecture is focused on decreasing quality of service (QoS parameters like latency, jitter, and packet loss, but other network features were not developed, like load balance or fault tolerance. In this paper, we propose a new fault tolerance mechanism, using as a base the MWAHCA architecture, in order to recover any multimedia flow crossing the wireless ad hoc network when there is a node failure. The algorithm can run independently for each multimedia flow. The main objective is to keep the QoS parameters as low as possible. To achieve this goal, the convergence time must be controlled and reduced. This paper provides the designed protocol, the analytical model of the algorithm, and a software application developed to test its performance in a real laboratory.

  13. Unikabeton Prototype

    DEFF Research Database (Denmark)

    Søndergaard, Asbjørn; Dombernowsky, Per

    2011-01-01

    The Unikabeton prototype structure was developed as the finalization of the cross-disciplinary research project Unikabeton, exploring the architectural potential in linking the computational process of topology optimisation with robot fabrication of concrete casting moulds. The project was elabor......The Unikabeton prototype structure was developed as the finalization of the cross-disciplinary research project Unikabeton, exploring the architectural potential in linking the computational process of topology optimisation with robot fabrication of concrete casting moulds. The project...... of Architecture was to develop a series of optimisation experiments, concluding in the design and optimisation of a full scale prototype concrete structure....

  14. Comparison of Available Bandwidth Estimation Techniques in Packet-Switched Mobile Networks

    DEFF Research Database (Denmark)

    López Villa, Dimas; Ubeda Castellanos, Carlos; Teyeb, Oumer Mohammed

    2006-01-01

    of information regarding the available bandwidth in the transport network, as it could end up being the bottleneck rather than the air interface. This paper provides a comparative study of three well known available bandwidth estimation techniques, i.e. TOPP, SLoPS and pathChirp, taking into account......The relative contribution of the transport network towards the per-user capacity in mobile telecommunication systems is becoming very important due to the ever increasing air-interface data rates. Thus, resource management procedures such as admission, load and handover control can make use...... the statistical conditions of the available bandwidth and assessing the variability of their estimations. Simulation-based studies on a mobile transport network show that pathChirp outperforms TOPP and SLoPS, both in terms of accuracy and efficiency....

  15. A Small Data Center Network of ARP-Path Bridges made of Openflow Switches

    OpenAIRE

    Ibáñez Fernández, Guillermo Agustín; Rojas Sánchez, Elisa; Rivera, Diego; De Schuymer, Bart; Dietz, Thomas; Naous, Jad

    2011-01-01

    This demo shows, in a small data center demo network topology the ARP Path bridges functionality and robustness over varied platforms and their interoperability. ARP-Path bridges set up on-demand shortest paths between hosts using the standard ARP Request, but flooded over all links, to find the lowest latency path to the destination host. ARP Path is loop free, uses the standard Ethernet frame and compatible with hosts and routers.Data center demo network consists of ten ARP Path bridges. Ei...

  16. A Small Data Center Network of ARP-Path Bridges made of Openflow Switches

    OpenAIRE

    Ibáñez, Guillermo; Naous, J.; Rojas, Elisa; Rivera, Diego; De Schuymer, B.; Dietz, Thomas

    2011-01-01

    This work is at: The 36th IEEE Conference on Local Computer Networks (LCN) took place 04/10/2011 - 07/10/2011 in Bonn (Germany). This web site to: http://www.ieeelcn.org/prior/LCN36/index.html This demo shows, in a small data center demo network topology the ARP Path bridges functionality and robustness over varied platforms and their interoperability. ARP-Path bridges set up on-demand shortest paths between hosts using the standard ARP Request, but flooded over all links, to find the lo...

  17. Coherent optical orthogonal frequency-division multiplexing for optical slot switched intra-datacenters networks

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel; Mestre, Miquel A.; Jenneve, Philippe

    2015-01-01

    We propose low-overhead CO-OFDM-based flexible transponders for OSS intra-datacenter networks. Experimental validation is performed for up to 100 cascaded nodes, showing 50Gbps higher average rate, 40% extended reach, and >4GHz extra detuning tolerance than the Nyquist counterpart.......We propose low-overhead CO-OFDM-based flexible transponders for OSS intra-datacenter networks. Experimental validation is performed for up to 100 cascaded nodes, showing 50Gbps higher average rate, 40% extended reach, and >4GHz extra detuning tolerance than the Nyquist counterpart....

  18. Application prototype of a model-based expert system to the maintenance of a MAN

    Science.gov (United States)

    Hopfmueller, Heinrich; Kehl, Walter; Schapeler, Gottfried

    1993-10-01

    This paper describes the work done and results achieved in implementing a fault management prototype for a Metropolitan Area Network (MAN) switching system, the GMAN (GMS Fault Management Prototype for a MAN). The GMAN is implemented using the Generic Maintenance System (GMS) which has been developed by the RACE project AIM (R1006). The GMS is a model based expert system toolset (`2nd generation XPS') comprising components for knowledge acquisition, knowledge representation, model based reasoning, human machine interface, and dialogue design. The GMS supports automatic fault management from receiving and treating fault events to guiding an operator through a repair procedure.

  19. Blink-related dynamic switching between internal and external orienting networks while viewing videos.

    Science.gov (United States)

    Nakano, Tamami

    2015-07-01

    Humans spontaneously generate eyeblinks every few seconds. However, because this blink rate is several times more common than is required for ocular lubrication, the function of most spontaneous eyeblinks remains unknown. Because spontaneous eyeblinks tend to occur at implicit breakpoints in video stories, I hypothesized that spontaneous eyeblinks play an active role in attentional disengagement from external stimuli. Consistent with this, we previously found that spontaneous eyeblinks involve the concurrent deactivation of the dorsal attention network and activation of the default mode network when individuals are viewing videos. However, this previous study examined only the upper brain regions to increase the temporal resolution of the data. Therefore, the present study examined whether the temporal and subcortical regions exhibited blink-related activations or deactivations using the same visual stimuli as in the previous study. Data revealed that the bilateral hippocampus and cerebellum showed a prominent but momentary activation after the blink onset. In contrast, a blink-related deactivation was observed in both the right ventral and dorsal attention networks. These results suggest that spontaneous eyeblinks are involved in the attentional disengagement from external visual information via the massive and dynamic alteration of brain activity between the external and internal orienting networks. Copyright © 2015 The Author. Published by Elsevier Ireland Ltd.. All rights reserved.

  20. Five-port silicon optical router based on Mach—Zehnder optical switches for photonic networks-on-chip

    Science.gov (United States)

    Yunchou, Zhao; Hao, Jia; Jianfeng, Ding; Lei, Zhang; Xin, Fu; Lin, Yang

    2016-11-01

    With the continuous development of integrated circuits, the performance of the processor has been improved steadily. To integrate more cores in one processor is an effective way to improve the performance of the processor, while it is impossible to further improve the property of the processor by only increasing the clock frequency. For a processor with integrated multiple cores, its performance is determined not only by the number of cores, but also by communication efficiency between them. With more processor cores integrated on a chip, larger bandwidths are required to establish the communication among them. The traditional electrical interconnect has gradually become a bottleneck for improving the performance of multiple-core processors due to its limited bandwidth, high power consumption, and long latency. The optical interconnect is considered as a potential way to solve this issue. The optical router is the key device for realizing the optical interconnect. Its basic function is to achieve the data routing and switching between the local node and the multi-node. In this paper we present a five-port optical router for Mesh photonics network-on-chip. A five-port optical router composed of eight thermally tuned silicon Mach—Zehnder optical switches is demonstrated. The experimental spectral responses indicate that the optical signal-to-noise ratios of the optical router are over 13 dB in the wavelength range of 1525-1565 nm for all of its 20 optical links. Each optical link can manipulate 50 wavelength channels with the channel spacing of 100 GHz and the data rate of 32 Gbps for each wavelength channel in the same wavelength range. The lowest energy efficiency of the optical router is 43.4 fJ/bit. Project supported by the National High Technology Research and Development Program of China (Nos. 2015AA010103, 2015AA010901) and the National Natural Science Foundation of China (Nos. 61575187, 61235001, 61505198, 61377067).

  1. A scalable silicon photonic chip-scale optical switch for high performance computing systems.

    Science.gov (United States)

    Yu, Runxiang; Cheung, Stanley; Li, Yuliang; Okamoto, Katsunari; Proietti, Roberto; Yin, Yawei; Yoo, S J B

    2013-12-30

    This paper discusses the architecture and provides performance studies of a silicon photonic chip-scale optical switch for scalable interconnect network in high performance computing systems. The proposed switch exploits optical wavelength parallelism and wavelength routing characteristics of an Arrayed Waveguide Grating Router (AWGR) to allow contention resolution in the wavelength domain. Simulation results from a cycle-accurate network simulator indicate that, even with only two transmitter/receiver pairs per node, the switch exhibits lower end-to-end latency and higher throughput at high (>90%) input loads compared with electronic switches. On the device integration level, we propose to integrate all the components (ring modulators, photodetectors and AWGR) on a CMOS-compatible silicon photonic platform to ensure a compact, energy efficient and cost-effective device. We successfully demonstrate proof-of-concept routing functions on an 8 × 8 prototype fabricated using foundry services provided by OpSIS-IME.

  2. Adaptive Optical Burst Switching

    OpenAIRE

    Bonald, Thomas; Indre, Raluca-Maria; Oueslati, Sara

    2012-01-01

    International audience; We propose a modified version of Optical Burst Switching (OBS) that adapts the size of switched data units to the network load. Specifically, we propose a two-way reservation OBS scheme in which every active source-destination pair attempts to reserve a lightpath and for every successful reservation, transmits an optical burst whose size is proportional to the number of active data flows. We refer to this technique as Adaptive Optical Burst Switching. We prove that the...

  3. Evaluation of QoS differentiation mechanisms in asynchronous bufferless optical packet-switched networks

    DEFF Research Database (Denmark)

    Overby, H.; Stol, N.; Nord, Martin

    2006-01-01

    Existing quality of service differentiation schemes for today's IP over point-to-point optical WDM networks take advantage of electronic RAM to implement traffic management algorithms in order to isolate the service classes. Since practical optical RAM is not available, these techniques...... the performance of the presented schemes and qualitatively discuss implementation issues, in order to evaluate the mechanisms. In particular, we present an evaluation framework, which quantifies the throughput reduction observed when migrating from a best effort scenario to a service-differentiated scenario. Our...... study shows that preemption-based schemes have the best performance, but also the highest implementation complexity....

  4. The Kaleidoscope switch-a new concept for implementation of a large and fault tolerant ATM switch system

    DEFF Research Database (Denmark)

    Dittmann, Lars

    1997-01-01

    This paper describes a new concept for implementing a large switch network based on smaller modules. The concept is based an an alternative self-routing structure that due to a point symmetry allows the bit in the routing tag to be processed in a random order. Among others this property provides ...... an inherent fault protection and allows a simple implementation of broadcast and multicast. The concept has been implemented as a small prototype, that currently is used in a national experimental ATM network in Denmark...

  5. MPK-1/ERK regulatory network controls the number of sperm by regulating timing of sperm-oocyte switch in C. elegans germline.

    Science.gov (United States)

    Yoon, Dong Suk; Alfhili, Mohammad A; Friend, Kyle; Lee, Myon-Hee

    2017-09-30

    The precise regulation of germline sexual fate is crucial for animal fertility. In C. elegans, the production of either type of gamete, sperm or oocyte, becomes mutually exclusive beyond the larval stage. Hermaphrodites initially produce sperm and then switch to produce oocytes. This change of fate during germline development is tightly controlled by several regulators. In C. elegans hermaphrodites, FBF-1 and FBF-2 (>95% identical, members of the Pumilio RNA-binding protein family) proteins function redundantly to promote the sperm-oocyte switch. Here, we demonstrate that loss of LIP-1 (dual specificity phosphatase) in fbf-1(ok91) single mutants leads to excess sperm production due to a delayed sperm-oocyte switch. This phenotype was dramatically rescued by depletion of MPK-1 (an ERK homolog). In contrast, loss of LIP-1 in fbf-2(q738) single mutants leads to a premature sperm-oocyte switch and loss of sperm. Notably, fbf-1 fbf-2; lip-1 triple mutants produce excess sperm. These results suggest that the MPK-1/ERK regulatory network, including FBF-1, FBF-2, and LIP-1, controls the number of sperm by regulating the timing of the sperm-oocyte switch in C. elegans. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. On the performance of a scalable optical switching architecture for flat intercluster data center network with centralized control

    Science.gov (United States)

    Kong, Qian; Huang, Shanguo; Zhou, Yu; Guo, Bingli; Zhao, Yongli; Zhang, Min; Zhang, Jie; Gu, Wanyi

    2014-07-01

    Data centers have to sustain the rapid growth of data traffic due to the increasing demand of bandwidth-hungry Internet services. The current fat tree topology causes communication bottlenecks in the server interaction process, resulting in power-hungry O-E-O conversions that limit the minimum latency and the power efficiency of these systems. As a result, recent efforts have advocated that all optical data center networks (DCNs) have the capability to adapt to traffic requirements on demand. We present the design, implementation, and evaluation of a cascaded microelectromechanical systems switches-based DCN architecture which dynamically changes its topology and link capacities, thereby achieving unprecedented flexibility to adapt to dynamic traffic patterns. We analyze it under a data center traffic model to determine its suitability for this type of environment. The proposed architecture can be scaled to 3300 input/output ports by available experimental components with low blocking probability and latency. The blocking probability and latency are about 0.03 and 72 ms at a moderate traffic load for 32 input/output ports based on our numerical results, which are much smaller than the results for 4 input/output ports which are 0.13 and 235 ms, respectively.

  7. Prioritizing Data/Energy Thresholding-Based Antenna Switching for SWIPT-Enabled Secondary Receiver in Cognitive Radio Networks

    KAUST Repository

    Benkhelifa, Fatma

    2017-12-04

    Simultaneous wireless power and information transfer (SWIPT) is considered in cognitive radio networks with a multi-antenna energy harvesting (EH) secondary receiver (SR). The SR harvests the energy from the secondary transmitter and primary transmitter. The SR uses the antenna switching technique which selects a subset of antennas to decode the information (namely the information decoding (ID) antennas) and the rest to harvest the energy (namely the EH antennas). The AS technique is performed via a thresholding-based strategy inspired from the maximum ratio combining technique with an output threshold (OT-MRC) which is proposed in two ways: the prioritizing data selection (PDS) scheme, and the prioritizing energy selection (PES) scheme. For both schemes, we study the expressions and the asymptotic results of the probability mass function of the selected ID antennas, the average harvested energy, the power outage probability, and the data outage probability. We deduce the performance of the joint PDS and PES scheme. We evaluate all performance metrics for the Rayleigh and Nakagami fading channels. Through the simulation results, we show the impact of different simulation parameters on the performance metrics. We also show that there is a tradeoff between the data and energy performance metrics.

  8. A Thresholding-Based Antenna Switching in SWIPT-Enabled MIMO Cognitive Radio Networks with Co-Channel Interference

    KAUST Repository

    Benkhelifa, Fatma

    2016-10-23

    In this paper, we consider the simultaneous wireless power and information transfer (SWIPT) for spectrum sharing (SS) in cognitive radio (CR) networks with a multiple antenna SWIPT-Enabled secondary receiver (SR). The SR harvests the energy from the signals sent from the secondary transmitter (ST) and the interfering signals sent from the primary transmitter (PT). Moreover, the ST uses the antenna switching (AS) technique which selects a subset of the antennas to decode the information and the rest to harvest the energy. The antenna selection is performed via a thresholding strategy inspired from the maximum ratio combining (MRC) technique with an output threshold (OT-MRC). The thresholding-based antenna selection strategy is proposed in two ways: one is prioritizing the information data and the other is prioritizing the harvested energy. For the two proposed selection schemes, we study the probability mass function of the selected antennas, the average harvested energy, and the data transmission outage probability. Through the analytic expressions and the simulation results, we show that there is a tradeoff between the outage probability and the harvested energy for both schemes. We see also that the preference of one scheme on the other is also affected by this energy-data trade off.

  9. An X-band 22.5°/45° digital phase shifter based on switched filter networks

    Science.gov (United States)

    Sun, Pengpeng; Liu, Hui; Geng, Miao; Zhang, Rong; Wang, Qi; Luo, Weijun

    2017-06-01

    The design approach and performance of a 22.5°/45° digital phase shifter based on a switched filter network for X-band phased arrays are described. Both the MMIC phase shifters are fabricated employing a 0.25 μm gate GaAs pHEMT process and share in the same chip size of 0.82 × 1.06 mm2. The measurement results of the proposed phase shifters over the whole operating frequency range show that the phase shift error is less than 22.5°± 2.5°, 45°± 3.5°, which shows an excellent agreement with the simulated performance, the insertion loss is within the range of 0.9-1.2 dB for the 22.5° phase shifter and 0.9-1.4 dB for the 45° phase shifter, and the input/output return loss is better than -12.5 and -11 dB respectively. They also achieve the similar {P}1{{dB}} continuous wave power handing capability of 24.8 dBm at 10 GHz. The phase shifters show a good phase shift error, insertion loss and return loss in the X-band (40%), which can be employed into the wide bandwidth multi-bit digital phase shifter.

  10. A thresholding-based antenna switching in MIMO cognitive radio networks with SWIPT-enabled secondary receiver

    KAUST Repository

    Benkhelifa, Fatma

    2017-07-31

    Simultaneous wireless power and information transfer (SWIPT) in a cognitive radio (CR) network is considered where a multiple antenna energy harvesting (EH) secondary receiver (SR) harvests the energy using the antenna switching (AS) technique. In fact, the AS technique selects a subset of the SR antennas to decode the information (namely the information decoding (ID) antennas) and the rest to harvest the energy (namely the EH antennas). In this context, we propose a thresholding-based antenna selection strategy, termed as the prioritizing data selection (PDS) scheme, which selects the ID antennas such that the received power from the secondary transmitter (ST) at these antennas is above a certain threshold. For this scheme, we derive the analytic expressions of the probability mass function (PMF) of the selected ID antennas, the average harvested energy, and the outage probability. In the simulation results, we illustrate the performance of the PDS scheme and we compare it to the prioritizing energy selection (PES) scheme which selects the EH antennas such that the received power from ST at these antennas is above a certain threshold. For both schemes, we show that there is a tradeoff between the outage probability and the average harvested energy.

  11. Settlement in modern network-based payment infrastructures – description and prototype of the E-Settlement model

    OpenAIRE

    Leinonen, Harry; Lumiala, Veli-Matti; Sarlin, Riku

    2002-01-01

    Payment systems are undergoing rapid and fundamental changes stimulated largely by technological progress especially distributed network technology and real-time processing. Internet and e-commerce will have a major impact on payment systems in the future. User demands and competition will speed up developments. Payment systems will move from conventions that were originally paper-based to truly network-based solutions. This paper presents a solution – E-Settlement – for improving interbank s...

  12. Greenbrier Prototype

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-06-18

    This case study describes a prototype home that is the model home for the Homes at Greenbrier in Oakdale, Connecticut, and demonstrates the builder's concept of “attainable sustainable” of offering high performance homes at mid-market prices.

  13. Experimental Demonstration of Optical Switching of Tbit/s Data Packets for High Capacity Short-Range Networks

    DEFF Research Database (Denmark)

    Medhin, Ashenafi Kiros; Kamchevska, Valerija; Hu, Hao

    2015-01-01

    Record-high 1.28-Tbit/s optical data packets are experimentally switched in the optical domain using a LiNbO3 switch. An in-band notch-filter labeling scheme scalable to 65,536 labels is employed and a 3-km transmission distance is demonstrated.......Record-high 1.28-Tbit/s optical data packets are experimentally switched in the optical domain using a LiNbO3 switch. An in-band notch-filter labeling scheme scalable to 65,536 labels is employed and a 3-km transmission distance is demonstrated....

  14. Design Science Research toward Designing/Prototyping a Repeatable Model for Testing Location Management (LM) Algorithms for Wireless Networking

    Science.gov (United States)

    Peacock, Christopher

    2012-01-01

    The purpose of this research effort was to develop a model that provides repeatable Location Management (LM) testing using a network simulation tool, QualNet version 5.1 (2011). The model will provide current and future protocol developers a framework to simulate stable protocol environments for development. This study used the Design Science…

  15. A hybrid artificial neural network/genetic algorithm approach to on-line switching operations for the optimization of electrical power systems

    Energy Technology Data Exchange (ETDEWEB)

    Arjona, D.; Lay, R.K.; Harrington, R.J. [George Washington Univ., Washington, DC (United States)

    1996-12-31

    This paper is intended to present an approach to decision making in the operation of electrical power systems that will use a simple genetic algorithm as a teacher for the process of supervised learning of a feedforward, backpropagation artificial neural network. The fitness function used in the genetic algorithm is based on a load flow program and used to determine the optimal condition of the critical switches of the system. Reward and penalty functions are applied to it in order to emphasize environmental, economic, security, robustness, public policy and other considerations as they are predetermined by the philosophy of operation of the utility. These considerations (policies) become a part of the training set and operation of the neural network. The fitness function used by the genetic algorithm in order to rank the possible solutions is based on a load flow program. The binary nature of the genetic algorithm is particularly appropriate for the operation of switches. The result of the methodology is the equivalent of an on-line implicit load flow program used to redesign the configuration of the system in real time by opening and closing critical switches that are placed along the power system. Experiments leading towards the development of this methodology using real data from the Peninsular Control Area (the Yucatan Peninsula) of the National Mexican Interconnected Power Grid are presented.

  16. Rapid Prototyping

    Science.gov (United States)

    1999-01-01

    Javelin, a Lone Peak Engineering Inc. Company has introduced the SteamRoller(TM) System as a commercial product. The system was designed by Javelin during a Phase II NASA funded small commercial product. The purpose of the invention was to allow automated-feed of flexible ceramic tapes to the Laminated Object Manufacturing rapid prototyping equipment. The ceramic material that Javelin was working with during the Phase II project is silicon nitride. This engineered ceramic material is of interest for space-based component.

  17. Prototyping a Web-of-Energy Architecture for Smart Integration of Sensor Networks in Smart Grids Domain.

    Science.gov (United States)

    Caballero, Víctor; Vernet, David; Zaballos, Agustín; Corral, Guiomar

    2018-01-30

    Sensor networks and the Internet of Things have driven the evolution of traditional electric power distribution networks towards a new paradigm referred to as Smart Grid. However, the different elements that compose the Information and Communication Technologies (ICTs) layer of a Smart Grid are usually conceived as isolated systems that typically result in rigid hardware architectures which are hard to interoperate, manage, and to adapt to new situations. If the Smart Grid paradigm has to be presented as a solution to the demand for distributed and intelligent energy management system, it is necessary to deploy innovative IT infrastructures to support these smart functions. One of the main issues of Smart Grids is the heterogeneity of communication protocols used by the smart sensor devices that integrate them. The use of the concept of the Web of Things is proposed in this work to tackle this problem. More specifically, the implementation of a Smart Grid's Web of Things, coined as the Web of Energy is introduced. The purpose of this paper is to propose the usage of Web of Energy by means of the Actor Model paradigm to address the latent deployment and management limitations of Smart Grids. Smart Grid designers can use the Actor Model as a design model for an infrastructure that supports the intelligent functions demanded and is capable of grouping and converting the heterogeneity of traditional infrastructures into the homogeneity feature of the Web of Things. Conducted experimentations endorse the feasibility of this solution and encourage practitioners to point their efforts in this direction.

  18. How to Enhance the Efficiency of Loss-Less Optical Burst Switching Networks with the Streamline Effect

    National Research Council Canada - National Science Library

    Milos Kozak; Brigitte Jaumarad; Leos Bohac

    2015-01-01

    .... Therefore, this paper suggests a way how to efficiently and economically achieve this goal in the context of optical burst switching, a very promising technology that has been proposed to overcome...

  19. Prototyping a Web-of-Energy Architecture for Smart Integration of Sensor Networks in Smart Grids Domain

    Directory of Open Access Journals (Sweden)

    Víctor Caballero

    2018-01-01

    Full Text Available Sensor networks and the Internet of Things have driven the evolution of traditional electric power distribution networks towards a new paradigm referred to as Smart Grid. However, the different elements that compose the Information and Communication Technologies (ICTs layer of a Smart Grid are usually conceived as isolated systems that typically result in rigid hardware architectures which are hard to interoperate, manage, and to adapt to new situations. If the Smart Grid paradigm has to be presented as a solution to the demand for distributed and intelligent energy management system, it is necessary to deploy innovative IT infrastructures to support these smart functions. One of the main issues of Smart Grids is the heterogeneity of communication protocols used by the smart sensor devices that integrate them. The use of the concept of the Web of Things is proposed in this work to tackle this problem. More specifically, the implementation of a Smart Grid’s Web of Things, coined as the Web of Energy is introduced. The purpose of this paper is to propose the usage of Web of Energy by means of the Actor Model paradigm to address the latent deployment and management limitations of Smart Grids. Smart Grid designers can use the Actor Model as a design model for an infrastructure that supports the intelligent functions demanded and is capable of grouping and converting the heterogeneity of traditional infrastructures into the homogeneity feature of the Web of Things. Conducted experimentations endorse the feasibility of this solution and encourage practitioners to point their efforts in this direction.

  20. JUNOS Enterprise Switching

    CERN Document Server

    Reynolds, Harry

    2009-01-01

    JUNOS Enterprise Switching is the only detailed technical book on Juniper Networks' new Ethernet-switching EX product platform. With this book, you'll learn all about the hardware and ASIC design prowess of the EX platform, as well as the JUNOS Software that powers it. Not only is this extremely practical book a useful, hands-on manual to the EX platform, it also makes an excellent study guide for certification exams in the JNTCP enterprise tracks. The authors have based JUNOS Enterprise Switching on their own Juniper training practices and programs, as well as the configuration, maintenanc

  1. Optical switching using IP protocol

    Science.gov (United States)

    Utreras, Andres J.; Gusqui, Luis; Reyes, Andres; Mena, Ricardo I.; Licenko, Gennady L.; Amirgaliyev, Yedilkhan; Komada, Paweł; Luganskaya, Saule; Kashaganova, Gulzhan

    2017-08-01

    To understand and evaluate the Optical Layer, and how it will affect the IP protocols over WDM (Switching), the present analyse is proposed. Optical communications have attractive proprieties, but also have some disadvantages, so the challenge is to combine the best of both branches. In this paper, general concepts for different options of switching are reviewed as: optical burst switching (OBS) and automatically switching optical network (ASON). Specific details such as their architectures are also discussed. In addition, the relevant characteristics of each variation for switching are reviewed.

  2. Impact of dispersion forces on the atomic structure of a prototypical network-forming disordered system: The case of liquid GeSe2

    Science.gov (United States)

    Lampin, Evelyne; Bouzid, Assil; Ori, Guido; Boero, Mauro; Massobrio, Carlo

    2017-07-01

    A set of structural properties of liquid GeSe2 are calculated by using first-principles molecular dynamics and including, for the first time, van der Waals dispersion forces. None of the numerous atomic-scale simulations performed in the past on this prototypical disordered network-forming material had ever accounted for dispersion forces in the expression of the total energy. For this purpose, we employed either the Grimme-D2 or the maximally localized Wannier function scheme. We assessed the impact of dispersion forces on properties such as partial structure factors, pair correlation functions, bond angle distribution, and number of corner vs edge sharing connections. The maximally localized Wannier function scheme is more reliable than the Grimme-D2 scheme in reproducing existing first-principles results. In particular, the Grimme-D2 scheme worsens the agreement with experiments in the case of the Ge-Ge pair correlation function. Our study shows that the impact of dispersion forces on disordered chalcogenides has to be considered with great care since it cannot be necessarily the same when adopting different recipes.

  3. Artificial neural networks for control of a grid-connected rectifier/inverter under disturbance, dynamic and power converter switching conditions.

    Science.gov (United States)

    Li, Shuhui; Fairbank, Michael; Johnson, Cameron; Wunsch, Donald C; Alonso, Eduardo; Proaño, Julio L

    2014-04-01

    Three-phase grid-connected converters are widely used in renewable and electric power system applications. Traditionally, grid-connected converters are controlled with standard decoupled d-q vector control mechanisms. However, recent studies indicate that such mechanisms show limitations in their applicability to dynamic systems. This paper investigates how to mitigate such restrictions using a neural network to control a grid-connected rectifier/inverter. The neural network implements a dynamic programming algorithm and is trained by using back-propagation through time. To enhance performance and stability under disturbance, additional strategies are adopted, including the use of integrals of error signals to the network inputs and the introduction of grid disturbance voltage to the outputs of a well-trained network. The performance of the neural-network controller is studied under typical vector control conditions and compared against conventional vector control methods, which demonstrates that the neural vector control strategy proposed in this paper is effective. Even in dynamic and power converter switching environments, the neural vector controller shows strong ability to trace rapidly changing reference commands, tolerate system disturbances, and satisfy control requirements for a faulted power system.

  4. Overvoltages during switching operations of vacuum switching devices

    Directory of Open Access Journals (Sweden)

    Vukelja Petar

    2013-01-01

    Full Text Available This paper presents the results of experimental studies of voltage phenomena in the switching operations of vacuum switching devices made by various manufacturers in several different configurations of 6 kV, 10 kV, 20 kV and 35 kV networks. During switching-on operations of the inductive loads, re-ignition of the electric arc between the contacts of the vacuum switching devices appears. Each arc ignition appearance leads to overvoltages with gradients close to those of lightning overvoltages. Switching-off operations of the inductive loads with vacuum switching devices leads to the cutting of the current before it passed through a natural zero and the appearance of multiple re-ignition of the arc between their contacts. All this leads to significant overvoltages on the equipment insulation. The analysis of surges in the studied networks, and the measures and means to reduce the stress of isolation are proposed.

  5. A Study of Quality of Service Communication for High-Speed Packet-Switching Computer Sub-Networks

    Science.gov (United States)

    Cui, Zhenqian

    1999-01-01

    With the development of high-speed networking technology, computer networks, including local-area networks (LANs), wide-area networks (WANs) and the Internet, are extending their traditional roles of carrying computer data. They are being used for Internet telephony, multimedia applications such as conferencing and video on demand, distributed simulations, and other real-time applications. LANs are even used for distributed real-time process control and computing as a cost-effective approach. Differing from traditional data transfer, these new classes of high-speed network applications (video, audio, real-time process control, and others) are delay sensitive. The usefulness of data depends not only on the correctness of received data, but also the time that data are received. In other words, these new classes of applications require networks to provide guaranteed services or quality of service (QoS). Quality of service can be defined by a set of parameters and reflects a user's expectation about the underlying network's behavior. Traditionally, distinct services are provided by different kinds of networks. Voice services are provided by telephone networks, video services are provided by cable networks, and data transfer services are provided by computer networks. A single network providing different services is called an integrated-services network.

  6. Switching antidepressants

    African Journals Online (AJOL)

    may result in toxic drug-drug interactions, worsening depression or unpleasant discontinuation reactions. Switching strategies to minimise these risks include immediate switching, cross-tapering or incorporating a washout period. Immediate switching is generally possible when substituting a selective serotonin reuptake ...

  7. Optical Packet Switching Demostrator

    DEFF Research Database (Denmark)

    Mortensen, Brian Bach; Berger, Michael Stübert

    2002-01-01

    In the IST project DAVID (data and voice integration over DWDM) work is carried out defining possible architectures of future optical packet switched networks. The feasibility of the architecture is to be verified in a demonstration set-up. This article describes the demonstrator set-up and the m......In the IST project DAVID (data and voice integration over DWDM) work is carried out defining possible architectures of future optical packet switched networks. The feasibility of the architecture is to be verified in a demonstration set-up. This article describes the demonstrator set...

  8. Switch wear leveling

    Science.gov (United States)

    Wu, Hunter; Sealy, Kylee; Gilchrist, Aaron

    2015-09-01

    An apparatus for switch wear leveling includes a switching module that controls switching for two or more pairs of switches in a switching power converter. The switching module controls switches based on a duty cycle control technique and closes and opens each switch in a switching sequence. The pairs of switches connect to a positive and negative terminal of a DC voltage source. For a first switching sequence a first switch of a pair of switches has a higher switching power loss than a second switch of the pair of switches. The apparatus includes a switch rotation module that changes the switching sequence of the two or more pairs of switches from the first switching sequence to a second switching sequence. The second switch of a pair of switches has a higher switching power loss than the first switch of the pair of switches during the second switching sequence.

  9. Performance enhancements of the CMCC"s national mesh network using the intelligent optical cross-connect switches

    Science.gov (United States)

    Gong, Qian; Xu, Rong; Lin, JinTong L.

    2004-04-01

    In the last five years, the traffic growth rate in China has been extremely fast. By 2005, the number of wired telephone customers is estimated to reach 220 to 260 million, while the number of expected cellular customers will reach 260 to 290 million. To meet these challenges, we will continue evolving with more wavelengths and higher speed. By evolving point-to-point WDM systems to OTN/ASON systems, we can eliminate the throughput bottleneck of network nodes caused by electronics, provide optical-layer bandwidth- management capability, provide scalability (which allows continuous traffic growth and network expansion), and provide reconfigurability (which allows semi-dynamic and dynamic optical networking). We can also simplify and speed up provisioning of high-speed circuits and services and offer fast network protection and restoration on the order of tens or hundreds of milliseconds to guarantee excellent network and service survivability. The CMCC (China Mobile Communication Company) will build its OTN network towards the ASON. The CMCC"s long-haul national network utilizing OXC has clearly becomes an intelligent network. It offers end-to-end point-and-click provisioning, shared mesh restoration with a few tens to a couple of hundred msec restoration times, re-provisioning of connections in the event of double failures and network capacity that is not optimally used. In this paper, first we present the CMCC network situation, The network planning tool will be introduced, Then we compare ring with mesh solution in terms of the cost, network performance, protection and restoration, network re-optimization. At last we derive a desired conclusion.

  10. System design document for the INFLO prototype.

    Science.gov (United States)

    2014-03-01

    This report documents the high level System Design Document (SDD) for the prototype development and : demonstration of the Intelligent Network Flow Optimization (INFLO) application bundle, with a focus on the Speed : Harmonization (SPD-HARM) and Queu...

  11. The Octopus switch

    NARCIS (Netherlands)

    Havinga, Paul J.M.

    2000-01-01

    This chapter1 discusses the interconnection architecture of the Mobile Digital Companion. The approach to build a low-power handheld multimedia computer presented here is to have autonomous, reconfigurable modules such as network, video and audio devices, interconnected by a switch rather than by a

  12. Potential of energy-oriented network optimisation: Switching off over-capacity in off-peak hours

    NARCIS (Netherlands)

    Litjens, R.; Jorguseski, L.

    2010-01-01

    Mobile communication networks are usually planned to provide some minimum service quality level during peak traffic hours. Consequently, in off-peak hours, when traffic loads are lower, the network is characterised by over-capacity, in the sense that same service quality targets can typically be

  13. Reconstruction of a metabolic regulatory network in Escherichia coli for purposeful switching from cell growth mode to production mode in direct GABA fermentation from glucose.

    Science.gov (United States)

    Soma, Yuki; Fujiwara, Yuri; Nakagawa, Takuya; Tsuruno, Keigo; Hanai, Taizo

    2017-09-01

    γ-aminobutyric acid (GABA) is a drug and functional food additive and is used as a monomer for producing the biodegradable plastic, polyamide 4. Recently, direct GABA fermentation from glucose has been developed as an alternative to glutamate-based whole cell bioconversion. Although total productivity in fermentation is determined by the specific productivity and cell amount responsible for GABA production, the optimal metabolic state for GABA production conflicts with that for bacterial cell growth. Herein, we demonstrated metabolic state switching from the cell growth mode based on the metabolic pathways of the wild type strain to a GABA production mode based on a synthetic metabolic pathway in Escherichia coli through rewriting of the metabolic regulatory network and pathway engineering. The GABA production mode was achieved by multiple strategies such as conditional interruption of the TCA and glyoxylate cycles, engineering of GABA production pathway including a bypass for precursor metabolite supply, and upregulation of GABA transporter. As a result, we achieved 3-fold improvement in total GABA production titer and yield (4.8g/L, 49.2% (mol/mol glucose)) in batch fermentation compared to the case without metabolic state switching (1.6g/L, 16.4% (mol/mol glucose)). This study reports the highest GABA production performance among previous reports on GABA fermentation from glucose using engineered E. coli. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  14. A CMOS vision chip for a contrast-enhanced image using a logarithmic APS and a switch-selective resistive network

    Science.gov (United States)

    Kong, Jae-Sung; Kim, Sang-Heon; Sung, Dong-Kyu; Seo, Sang-Ho; Shin, Jang-Kyoo

    2007-02-01

    In this paper, a vision chip for a contrast-enhanced image based on a structure of a biological retina is introduced. The key advantage of this structure is high speed of signal processing. In a conventional active pixel sensor (APS), the charge accumulation time limits its operation speed. In order to enhance the speed, a logarithmic APS was applied to the vision chip. By applying a MOS-type photodetector to the logarithmic APS, we could achieve sufficient output swing for the vision chip in natural illumination condition. In addition, a CMOS buffer circuit, a common drain amplifier, is commonly used for both raw and smoothed images by using additional switches. By using the switch-selective resistive network, the total number of MOSFETs for a unit pixel and the fixed-pattern noise were reduced. A vision chip with a 160×120 pixel array was fabricated using a 0.35 μm double-poly four-metal CMOS technology, and its operation was experimentally investigated.

  15. Recent developments in switching theory

    CERN Document Server

    Mukhopadhyay, Amar

    2013-01-01

    Electrical Science Series: Recent Developments in Switching Theory covers the progress in the study of the switching theory. The book discusses the simplified proof of Post's theorem on completeness of logic primitives; the role of feedback in combinational switching circuits; and the systematic procedure for the design of Lupanov decoding networks. The text also describes the classical results on counting theorems and their application to the classification of switching functions under different notions of equivalence, including linear and affine equivalences. The development of abstract har

  16. Software Switching for Data Acquisition

    CERN Multimedia

    CERN. Geneva; Malone, David

    2016-01-01

    In this talk we discuss the feasibility of replacing telecom-class routers with a topology of commodity servers acting as software switches in data acquisition. We extend the popular software switch, Open vSwitch, with a dedicated, throughput-oriented buffering mechanism. We compare the performance under heavy many-to-one congestion to typical Ethernet switches and evaluate the scalability when building larger topologies, exploiting the integration with software-defined networking technologies. Please note that David Malone will speak on behalf of Grzegorz Jereczek.

  17. NEBULAS a high performance data-driven event-building architecture based on an asynchronous self-routing packet-switching network

    CERN Document Server

    Christiansen, J; Letheren, M F; Marchioro, A; Tenhunen, H; Nummela, A; Nurmi, J; Gomes, P; Mandjavidze, I D; CERN. Geneva. Detector Research and Development Committee

    1992-01-01

    We propose a new approach to event building in future high rate experiments such as those at the LHC. We use a real-time, hierarchical event filtering paradigm based on pipelined triggering and data buffering at level 1, followed by farms of several hundreds of independent processors operating at level 2 and level 3. In view of the uncertainty in the rates and event sizes expected after the first level trigger in LHC experiments, it is important that data acquisition architectures can be open- endedly scaled to handle higher global bandwidths and accommodate more processors. We propose to apply the principle of self-routing packet-switching networks (currently under industrial development for telecommunications and multi-processor applications) to event building. We plan to implement a conceptually simple, distributed, asynchronous, data-driven, scalable, bottleneck-free architecture. An important feature of the architecture is that it can satisfy the data acquisition system's performance requirements using o...

  18. OCDMA PON supporting ONU inter-networking based on gain-switched Fabry-Pérot lasers with external dual-wavelength injection.

    Science.gov (United States)

    Liu, Jie; Zeng, Duoduo; Guo, Changjian; Xu, Lei; He, Sailing

    2010-10-25

    We propose and demonstrate an OCDMA-PON scheme with optical network unit (ONU) internetworking capability, which utilizes low-cost gain-switched Fabry-Pérot (GS-FP) lasers with external dual-wavelength injection as the pulse sources on the ONU side. The injection-generated optical pulses in two wavelengths from the same GS-FP laser are used separately for the PON uplink transmission and ONU internetworking. Experimental results based on a two-user OCDMA system confirm the feasibility of the proposed scheme. With OCDMA technologies, separate ONU-internetworking groups can be established using different optical codes. We also give experiment results to analyze the performance of the ONU-ONU transmission at different power of interference signals when two ONU-internetworking groups are present in the OCDMA-PON.

  19. Image Understanding Architecture Prototype Evaluation and Development

    Science.gov (United States)

    1993-06-01

    Edward M. Riseman, David B. Shu, and J. Gregory Nash, The Image Understanding Architecture, International Journal of Computer Vision, Vol. 2, Kluwer...and (statically connected) Networks [ Hockney 851. In a Switched-system, shown in figure 2.4, a switch [U unit (also called communication network...computing can be found in ( Hockney 85]. 2.12 Our terminology for identifying Parallel Systems The functional model of the ICAP covers more than one

  20. Proposal of dynamic protection/restoration schemes for QoS support in labeled optical burst switching networks

    Science.gov (United States)

    Yin, Yawei; Chi, Shuli; Shi, Jindan; Wu, Jian; Hong, Xiaobin; Lin, Jintong

    2008-11-01

    In this paper, two novel protection and restoration schemes were proposed by using the BC and BR schemes which were originally designed to reduce the bursts loss probability due to contention in OBS network. The 1+1 protection scheme in LOBS can be easily carried out using the MPLS 1+1 protection scheme in the 2.5 layer and burst cloning scheme in the OBS layer. By introducing some new OSPF-TE opaque LSA messages, the burst retransmission scheme can be transplanted into the restoration scheme in LOBS network. Furthermore, the dynamic quality of resilience mechanism to inherit these two schemes according to the QoS requirement of the traffic was also investigated. Experimental study using a LOBS network test bed verified that the proposed schemes suited well in the LOBS network.

  1. ELECTRIC MOTOR DIAGNOSTICS OF SWITCHES BASED ON THE NEURAL NETWORK DATA MODELING THE SPECTRAL DECOMPOSITION OF THE CURRENTS

    Directory of Open Access Journals (Sweden)

    O. M. Shvets

    2009-07-01

    Full Text Available The method of automated diagnostics of electric motors is offered. It uses a neural network revealing the electric motor faults on the basis of analysis of frequency spectrum of current flowing through the motor.

  2. Sequential multi-channel OCT in the retina using high-speed fiber optic switches

    Science.gov (United States)

    Wartak, Andreas; Augustin, Marco; Beer, Florian; Haindl, Richard; Baumann, Bernhard; Pircher, Michael; Hitzenberger, Christoph K.

    2017-07-01

    A sequential multi-channel OCT prototype featuring high-speed fiber optical switches to enable inter A-scan (A-scan rate: 100 kHz) sample arm switching was developed and human retinal image data is presented.

  3. Integrated Network Analysis Identifies Fight-Club Nodes as a Class of Hubs Encompassing Key Putative Switch Genes That Induce Major Transcriptome Reprogramming during Grapevine Development[W][OPEN

    Science.gov (United States)

    Palumbo, Maria Concetta; Zenoni, Sara; Fasoli, Marianna; Massonnet, Mélanie; Farina, Lorenzo; Castiglione, Filippo; Pezzotti, Mario; Paci, Paola

    2014-01-01

    We developed an approach that integrates different network-based methods to analyze the correlation network arising from large-scale gene expression data. By studying grapevine (Vitis vinifera) and tomato (Solanum lycopersicum) gene expression atlases and a grapevine berry transcriptomic data set during the transition from immature to mature growth, we identified a category named “fight-club hubs” characterized by a marked negative correlation with the expression profiles of neighboring genes in the network. A special subset named “switch genes” was identified, with the additional property of many significant negative correlations outside their own group in the network. Switch genes are involved in multiple processes and include transcription factors that may be considered master regulators of the previously reported transcriptome remodeling that marks the developmental shift from immature to mature growth. All switch genes, expressed at low levels in vegetative/green tissues, showed a significant increase in mature/woody organs, suggesting a potential regulatory role during the developmental transition. Finally, our analysis of tomato gene expression data sets showed that wild-type switch genes are downregulated in ripening-deficient mutants. The identification of known master regulators of tomato fruit maturation suggests our method is suitable for the detection of key regulators of organ development in different fleshy fruit crops. PMID:25490918

  4. Rapid prototype and test

    Energy Technology Data Exchange (ETDEWEB)

    Gregory, D.L.; Hansche, B.D.

    1996-06-01

    In order to support advanced manufacturing, Sandia has acquired the capability to produce plastic prototypes using stereolithography. Currently, these prototypes are used mainly to verify part geometry and ``fit and form`` checks. This project investigates methods for rapidly testing these plastic prototypes, and inferring from prototype test data actual metal part performance and behavior. Performances examined include static load/stress response, and structural dynamic (modal) and vibration behavior. The integration of advanced non-contacting measurement techniques including scanning laser velocimetry, laser holography, and thermoelasticity into testing of these prototypes is described. Photoelastic properties of the epoxy prototypes to reveal full field stress/strain fields are also explored.

  5. Shape-memory properties of magnetically active triple-shape nanocomposites based on a grafted polymer network with two crystallizable switching segments

    Directory of Open Access Journals (Sweden)

    A. Lendlein

    2012-01-01

    Full Text Available Thermo-sensitive shape-memory polymers (SMP, which are capable of memorizing two or more different shapes, have generated significant research and technological interest. A triple-shape effect (TSE of SMP can be activated e.g. by increasing the environmental temperature (Tenv, whereby two switching temperatures (Tsw have to be exceeded to enable the subsequent shape changes from shape (A to shape (B and finally the original shape (C. In this work, we explored the thermally and magnetically initiated shape-memory properties of triple-shape nanocomposites with various compositions and particle contents using different shape-memory creation procedures (SMCP. The nanocomposites were prepared by the incorporation of magnetite nanoparticles into a multiphase polymer network matrix with grafted polymer network architecture containing crystallizable poly(ethylene glycol (PEG side chains and poly(ε-caprolactone (PCL crosslinks named CLEGC. Excellent triple-shape properties were achieved for nanocomposites with high PEG weight fraction when two-step programming procedures were applied. In contrast, single-step programming resulted in dual-shape properties for all investigated materials as here the temporary shape (A was predominantly fixed by PCL crystallites.

  6. Architectures of prototypes and architectural prototyping

    DEFF Research Database (Denmark)

    Hansen, Klaus Marius; Christensen, Michael; Sandvad, Elmer

    1998-01-01

    This paper reports from experience obtained through development of a prototype of a global customer service system in a project involving a large shipping company and a university research group. The research group had no previous knowledge of the complex business of shipping and had never worked...... together as a team, but developed a prototype that more than fulfilled the expectations of the shipping company. The prototype should: - complete the first major phase within 10 weeks, - be highly vertical illustrating future work practice, - continuously live up to new requirements from prototyping...... sessions with users, - evolve over a long period of time to contain more functionality - allow for 6-7 developers working intensively in parallel. Explicit focus on the software architecture and letting the architecture evolve with the prototype played a major role in resolving these conflicting...

  7. Rethink! prototyping transdisciplinary concepts of prototyping

    CERN Document Server

    Nagy, Emilia; Stark, Rainer

    2016-01-01

    In this book, the authors describe the findings derived from interaction and cooperation between scientific actors employing diverse practices. They reflect on distinct prototyping concepts and examine the transformation of development culture in their fusion to hybrid approaches and solutions. The products of tomorrow are going to be multifunctional, interactive systems – and already are to some degree today. Collaboration across multiple disciplines is the only way to grasp their complexity in design concepts. This underscores the importance of reconsidering the prototyping process for the development of these systems, particularly in transdisciplinary research teams. “Rethinking Prototyping – new hybrid concepts for prototyping” was a transdisciplinary project that took up this challenge. The aim of this programmatic rethinking was to come up with a general concept of prototyping by combining innovative prototyping concepts, which had been researched and developed in three sub-projects: “Hybrid P...

  8. Analytical Performance Evaluation of Different Switch Solutions

    Directory of Open Access Journals (Sweden)

    Francisco Sans

    2013-01-01

    Full Text Available The virtualization of the network access layer has opened new doors in how we perceive networks. With this virtualization of the network, it is possible to transform a regular PC with several network interface cards into a switch. PC-based switches are becoming an alternative to off-the-shelf switches, since they are cheaper. For this reason, it is important to evaluate the performance of PC-based switches. In this paper, we present a performance evaluation of two PC-based switches, using Open vSwitch and LiSA, and compare their performance with an off-the-shelf Cisco switch. The RTT, throughput, and fairness for UDP are measured for both Ethernet and Fast Ethernet technologies. From this research, we can conclude that the Cisco switch presents the best performance, and both PC-based switches have similar performance. Between Open vSwitch and LiSA, Open vSwitch represents a better choice since it has more features and is currently actively developed.

  9. Geothermal switch heater installation, testing and monitoring : phases 1 & 2.

    Science.gov (United States)

    2016-07-01

    Transportation Technology Center, Inc. (TTCI), Norfolk Southern (NS), and John A. Volpe National Transportation Systems Center (Volpe) completed Phases 1 and 2 of a project on a working prototype geothermal switch heating system designed to test the ...

  10. Energy-Delay Tradeoff and Dynamic Sleep Switching for Bluetooth-Like Body-Area Sensor Networks

    CERN Document Server

    Rebeiz, Eric; Molisch, Andreas F

    2012-01-01

    Wireless technology enables novel approaches to healthcare, in particular the remote monitoring of vital signs and other parameters indicative of people's health. This paper considers a system scenario relevant to such applications, where a smart-phone acts as a data-collecting hub, gathering data from a number of wireless-capable body sensors, and relaying them to a healthcare provider host through standard existing cellular networks. Delay of critical data and sensors' energy efficiency are both relevant and conflicting issues. Therefore, it is important to operate the wireless body-area sensor network at some desired point close to the optimal energy-delay tradeoff curve. This tradeoff curve is a function of the employed physical-layer protocol: in particular, it depends on the multiple-access scheme and on the coding and modulation schemes available. In this work, we consider a protocol closely inspired by the widely-used Bluetooth standard. First, we consider the calculation of the minimum energy functio...

  11. Portable Userspace Virtual Filesystem Switch

    OpenAIRE

    Łukasz Faber; Krzysztof Boryczko

    2013-01-01

    Multiple different filesystems — including disk-based, network, distributed, abstract — arean integral part of every operating system. They are usually written as kernel modules and abstracted to the user via a virtual filesystem switch. In this paper we analyse the feasibility of reimplementing the virtual filesystem switch as a userspace daemon and applicability of this approach in real-life usage. Such reimplementation will require a way to virtualise processes behaviour related to filesys...

  12. Analysis, Design and Implementation of a Networking Proof-of-Concept Prototype to Support Maritime Visit, Board, Search and Seizure Teams

    Science.gov (United States)

    2014-03-01

    Radio Router setup o ATAK x 2 + charging cord x 1 (Brandon has these) o Laptop x 4 + power cord x 2 o Accessories o Charger base o Radio batteries x...11 c. Lower Infrastructure and Operational Costs .........................12 d. Reduced Power and Spectrum Requirements...teams. B. MESH NETWORKS A wireless mesh network (WMN) is a network that wirelessly applies multi -hop communications technology for forwarding

  13. Switching Processes in Queueing Models

    CERN Document Server

    Anisimov, Vladimir V

    2008-01-01

    Switching processes, invented by the author in 1977, is the main tool used in the investigation of traffic problems from automotive to telecommunications. The title provides a new approach to low traffic problems based on the analysis of flows of rare events and queuing models. In the case of fast switching, averaging principle and diffusion approximation results are proved and applied to the investigation of transient phenomena for wide classes of overloading queuing networks.  The book is devoted to developing the asymptotic theory for the class of switching queuing models which covers  mode

  14. Enhancing the Quality of Service for Real Time Traffic over Optical Burst Switching (OBS) Networks with Ensuring the Fairness for Other Traffics.

    Science.gov (United States)

    Al-Shargabi, Mohammed A; Shaikh, Asadullah; Ismail, Abdulsamad S

    2016-01-01

    Optical burst switching (OBS) networks have been attracting much consideration as a promising approach to build the next generation optical Internet. A solution for enhancing the Quality of Service (QoS) for high priority real time traffic over OBS with the fairness among the traffic types is absent in current OBS' QoS schemes. In this paper we present a novel Real Time Quality of Service with Fairness Ratio (RT-QoSFR) scheme that can adapt the burst assembly parameters according to the traffic QoS needs in order to enhance the real time traffic QoS requirements and to ensure the fairness for other traffic. The results show that RT-QoSFR scheme is able to fulfill the real time traffic requirements (end to end delay, and loss rate) ensuring the fairness for other traffics under various conditions such as the type of real time traffic and traffic load. RT-QoSFR can guarantee that the delay of the real time traffic packets does not exceed the maximum packets transfer delay value. Furthermore, it can reduce the real time traffic packets loss, at the same time guarantee the fairness for non real time traffic packets by determining the ratio of real time traffic inside the burst to be 50-60%, 30-40%, and 10-20% for high, normal, and low traffic loads respectively.

  15. Enhancing the Quality of Service for Real Time Traffic over Optical Burst Switching (OBS Networks with Ensuring the Fairness for Other Traffics.

    Directory of Open Access Journals (Sweden)

    Mohammed A Al-Shargabi

    Full Text Available Optical burst switching (OBS networks have been attracting much consideration as a promising approach to build the next generation optical Internet. A solution for enhancing the Quality of Service (QoS for high priority real time traffic over OBS with the fairness among the traffic types is absent in current OBS' QoS schemes. In this paper we present a novel Real Time Quality of Service with Fairness Ratio (RT-QoSFR scheme that can adapt the burst assembly parameters according to the traffic QoS needs in order to enhance the real time traffic QoS requirements and to ensure the fairness for other traffic. The results show that RT-QoSFR scheme is able to fulfill the real time traffic requirements (end to end delay, and loss rate ensuring the fairness for other traffics under various conditions such as the type of real time traffic and traffic load. RT-QoSFR can guarantee that the delay of the real time traffic packets does not exceed the maximum packets transfer delay value. Furthermore, it can reduce the real time traffic packets loss, at the same time guarantee the fairness for non real time traffic packets by determining the ratio of real time traffic inside the burst to be 50-60%, 30-40%, and 10-20% for high, normal, and low traffic loads respectively.

  16. Network topology mapper

    Science.gov (United States)

    Quist, Daniel A [Los Alamos, NM; Gavrilov, Eugene M [Los Alamos, NM; Fisk, Michael E [Jemez, NM

    2008-01-15

    A method enables the topology of an acyclic fully propagated network to be discovered. A list of switches that comprise the network is formed and the MAC address cache for each one of the switches is determined. For each pair of switches, from the MAC address caches the remaining switches that see the pair of switches are located. For each pair of switches the remaining switches are determined that see one of the pair of switches on a first port and the second one of the pair of switches on a second port. A list of insiders is formed for every pair of switches. It is determined whether the insider for each pair of switches is a graph edge and adjacent ones of the graph edges are determined. A symmetric adjacency matrix is formed from the graph edges to represent the topology of the data link network.

  17. MATHEMATIC SIMULATION OF TRANSIENT PROCESS IN A.C. – SYSTEM “ELECTRIC TRACTION NETWORK – LOCOMOTIVE” 1. SWITCH ON LOCOMOTIVE’S POWER CONVERTER IN “FREE PLAY” MODE; PARAMETERS ESTIMATION

    Directory of Open Access Journals (Sweden)

    T. M. Mishchenko

    2010-11-01

    Full Text Available In the article the electric circuit of substitution and mathematical model of the system of alternating current «traction substation − traction mains − electric locomotive DS 3» at switching its power transformer on in the idle mode are presented. Numerical determinations of parameters of traction substation, rails, contact network and transformer are executed; in so doing a special attention is paid to the estimation of dispersion inductance for the primary winding of transformer.

  18. Fabrication and Prototyping Lab

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose: The Fabrication and Prototyping Lab for composite structures provides a wide variety of fabrication capabilities critical to enabling hands-on research and...

  19. Rapid Prototyping Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The ARDEC Rapid Prototyping (RP) Laboratory was established in December 1992 to provide low cost RP capabilities to the ARDEC engineering community. The Stratasys,...

  20. Multi-planed unified switching topologies

    Science.gov (United States)

    Chen, Dong; Heidelberger, Philip; Sugawara, Yutaka

    2017-07-04

    An apparatus and method for extending the scalability and improving the partitionability of networks that contain all-to-all links for transporting packet traffic from a source endpoint to a destination endpoint with low per-endpoint (per-server) cost and a small number of hops. An all-to-all wiring in the baseline topology is decomposed into smaller all-to-all components in which each smaller all-to-all connection is replaced with star topology by using global switches. Stacking multiple copies of the star topology baseline network creates a multi-planed switching topology for transporting packet traffic. Point-to-point unified stacking method using global switch wiring methods connects multiple planes of a baseline topology by using the global switches to create a large network size with a low number of hops, i.e., low network latency. Grouped unified stacking method increases the scalability (network size) of a stacked topology.

  1. Beyond the switch

    DEFF Research Database (Denmark)

    Aliakseyeu, Dzmitry; Meerbeek, Bernt; Mason, Jon

    2014-01-01

    The commercial introduction of connected lighting that can be integrated with sensors and other devices is opening up new possibilities in creating responsive and intelligent environments. The role of lighting in such systems goes beyond simply functional illumination. In part due to the large...... is to explore new ways of interacting with light where lighting can not only be switched on or off, but is an intelligent system embedded in the environment capable of creating a variety of effects. The connectivity between multiple systems and other ecosystems, for example when transitioning from your home...... and established lighting network, and with the advent of the LED, new types of lighting output are now possible. However, the current approach for controlling such systems is to simply replace the light switch with a somewhat more sophisticated smartphone-based remote control. The focus of this workshop...

  2. EPCiR prototype

    DEFF Research Database (Denmark)

    2003-01-01

    A prototype of a residential pervasive computing platform based on OSGi involving among other a mock-up of an health care bandage.......A prototype of a residential pervasive computing platform based on OSGi involving among other a mock-up of an health care bandage....

  3. Innovation og prototyper

    DEFF Research Database (Denmark)

    Hansen, Svend Aage; Hansen, Erik; Kyvsgård, Poul H.

    2006-01-01

    Denne artikel advokerer for at danske virksomheder skal (gen)indføre prototyper som middel til at hurtigere at komme fra ide til salg og samtidig skabe et bedre produkt. LEGO og B&O gennemgår deres erfaringer med anvendelse af simple prototyper tidligt i det forløb, der nyudvikler et produkt. De...

  4. Controlled Photon Switch Assisted by Coupled Quantum Dots

    Science.gov (United States)

    Luo, Ming-Xing; Ma, Song-Ya; Chen, Xiu-Bo; Wang, Xiaojun

    2015-01-01

    Quantum switch is a primitive element in quantum network communication. In contrast to previous switch schemes on one degree of freedom (DOF) of quantum systems, we consider controlled switches of photon system with two DOFs. These controlled photon switches are constructed by exploring the optical selection rules derived from the quantum-dot spins in one-sided optical microcavities. Several double controlled-NOT gate on different joint systems are greatly simplified with an auxiliary DOF of the controlling photon. The photon switches show that two DOFs of photons can be independently transmitted in quantum networks. This result reduces the quantum resources for quantum network communication. PMID:26095049

  5. Modified Embedded Switched Inductor Z Source Inverter

    OpenAIRE

    V. Saravanan; R. Ramanujam; M. Arumugam

    2014-01-01

    A novel modified embedded switched inductor Z-source inverter is proposed by inserting the photovoltaic panels at various locations to improve the output voltage boosting performance. The proposed inverter have the concepts of embedded and switched inductor Z source network to have better features in terms of increased voltage boost inversion ability, continuous input current, reduced voltage stress on the switches/capacitors. Simulations are carried out by employing (120°) pulse width modula...

  6. Monolithic integrated switched-capacitor filters. I

    Science.gov (United States)

    Rienecker, W.

    1980-06-01

    The historical background of switched-capacitor filters is reviewed, and advanced design techniques for such filters are considered with reference to filter implementation in integrated systems. It is shown that basic equivalences between the components of time-invariant and time-variant networks make it possible to construct switched-capacitor filters that imitate classic filter types. Some examples of commercial switched-capacitor filters show the advantages of this technology.

  7. Cooperative Prototyping Experiments

    DEFF Research Database (Denmark)

    Bødker, Susanne; Grønbæk, Kaj

    1989-01-01

    This paper describes experiments with a design technique that we denote cooperative prototyping. The experiments consider design of a patient case record system for municipal dental clinics in which we used HyperCard, an off the shelf programming environment for the Macintosh. In the ecperiments we...... tried to achieve a fluent work-like evaluation of prototypes where users envisioned future work with a computer tool, at the same time as we made on-line modifications of prototypes in cooperation with the users when breakdown occur in their work-like evaluation. The experiments showed...... that it was possible to make a number of direct manipulation changes of prototypes in cooperation with the users, in interplay with their fluent work-like evaluation of these. However, breakdown occurred in the prototyping process when we reached the limits of the direct manipulation support for modification. From...

  8. Multiuser Switched Diversity Scheduling Schemes

    CERN Document Server

    Shaqfeh, Mohammad; Alouini, Mohamed-Slim

    2012-01-01

    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback sys...

  9. A Generic Maximum Delay Model of a Packet Switch | Eyinagho ...

    African Journals Online (AJOL)

    There has been a strong trend away from shared medium (in the most recent case, the use of hubs) in local area networks in favor of switched local area networks. The need for deterministic guarantees on delays when designing switched local area networks has also been recognized by many researchers as these delays ...

  10. Analysis and design of a high-efficiency zero-voltage-switching step ...

    Indian Academy of Sciences (India)

    The output diodes are under zero-current-switching (ZCS) during turn-off. Due to soft-switching operation of the power switches and output diodes, the proposed ZVS DC–DC converter shows high efficiency. Steady-state analysis of the converter is presented to determine the circuit parameters. A laboratory prototype of the ...

  11. Three Phase Six-Switch PWM Buck Rectifier with Power Factor Improvement

    DEFF Research Database (Denmark)

    Zafar Ullah Khan, M; Mohsin Naveed, M.; Hussain, Dil Muhammad Akbar

    2013-01-01

    variable output voltage. Small size energy storing components are required depending upon switching frequency. MATLAB simulation is performed and modified Sinusoidal Pulse Width Modulation(SPWM) switching technique is used in 3kW prototype converter to demonstrate low input current THD, nearly unity...... displacement factor, well regulated output voltage and reduced switching losses compared to conventional SPWM....

  12. Ada (Trade Name) Foundation Technology. Volume 9. Software Requirements for WIS (WWMCCS (World Wide Military Command and Control System) Information System) Network Protocol Prototypes.

    Science.gov (United States)

    1986-12-01

    Communications, January 1977. [ GAVI 83] Gavish, B., and S. L. Hantler, "An Algorithm for Optimal Route Selection in SNA Networks," IEEE Transactons on...can be found in [SCHW 80.1 Two works that deal with non-bifurcated flows are [COUR 8 11 and [ GAVI 83]. 4.3 Description of the Algorithm Problem 4.3.1

  13. SONG - getting ready for the prototype

    DEFF Research Database (Denmark)

    Grundahl, F.; Christensen-Dalsgaard, J.; Jørgensen, Uffe Gråe

    2011-01-01

    . At each of the network nodes a 1 m telescope with a high-resolution spectrograph and two lucky-imaging cameras is placed. The instruments and telescope, for the prototype node, are currently being built and installation at Observatorio del Teide, Tenerife, Spain is foreseen for early 2011....

  14. PRMS Data Warehousing Prototype

    Science.gov (United States)

    Guruvadoo, Eranna K.

    2002-01-01

    Project and Resource Management System (PRMS) is a web-based, mid-level management tool developed at KSC to provide a unified enterprise framework for Project and Mission management. The addition of a data warehouse as a strategic component to the PRMS is investigated through the analysis, design and implementation processes of a data warehouse prototype. As a proof of concept, a demonstration of the prototype with its OLAP's technology for multidimensional data analysis is made. The results of the data analysis and the design constraints are discussed. The prototype can be used to motivate interest and support for an operational data warehouse.

  15. New switching processes using the integrated protections of power semi-conductors: application to the development of static converters with self-switching process; nouveaux mecanismes de commutation exploitant les protections integrees des semi-conducteurs de puissance: application a la conception de convertisseurs statiques a commutation automatique

    Energy Technology Data Exchange (ETDEWEB)

    Roux, N.

    2004-07-15

    This thesis deals with a new switching process which integrates the semiconductor protection directly in the switching principle, in order to generate new static converters. It consists of a self-controlled transition which proceeds on a non-zero current or voltage level. 2 It can be associated with controlled or naturally switching processes making it possible to go from two to five change of state types of a switching cell. So, new elementary operation rules of a switching cell emerge. Considering the great number of possible switches, a synthesis methodology of cells with a source reversibility, whose switches are identical, is presented making it possible to reveal various solutions, of which two seem particularly interesting: the self-breaking inverter and rectifier cells, both using the self-breaking thyristor-dual. This last is used as study support of the self-breaking principle. Then, the manuscript concentrates on the study of converters, associations of elementary cells, revealing in particular the DC-current transformer and the reversible three-phase self-breaking rectifier. This last had been developed as an industrial prototype. Lastly, starting from the concept of a wind chain, our assembly has been compared with what is presently done as network converters, revealing lesser losses as well as a higher energetic efficiency. (author)

  16. LHC prototype magnet

    CERN Multimedia

    1991-01-01

    1.5 metre superconducting magnet. This prototype magnet for the LHC was cooled to a few degrees above absolute zero, which allowed it to obtain the world record for the highest magnetic field for an accelerator magnet in 1991.

  17. ICI Showcase House Prototype

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-02-16

    Building Science Corporation collaborated with ICI Homes in Daytona Beach, FL on a 2008 prototype Showcase House that demonstrates the energy efficiency and durability upgrades that ICI currently promotes through its in-house efficiency program called EFactor.

  18. Sonata: Query-Driven Network Telemetry

    KAUST Repository

    Gupta, Arpit

    2017-05-02

    Operating networks depends on collecting and analyzing measurement data. Current technologies do not make it easy to do so, typically because they separate data collection (e.g., packet capture or flow monitoring) from analysis, producing either too much data to answer a general question or too little data to answer a detailed question. In this paper, we present Sonata, a network telemetry system that uses a uniform query interface to drive the joint collection and analysis of network traffic. Sonata takes the advantage of two emerging technologies---streaming analytics platforms and programmable network devices---to facilitate joint collection and analysis. Sonata allows operators to more directly express network traffic analysis tasks in terms of a high-level language. The underlying runtime partitions each query into a portion that runs on the switch and another that runs on the streaming analytics platform iteratively refines the query to efficiently capture only the traffic that pertains to the operator\\'s query, and exploits sketches to reduce state in switches in exchange for more approximate results. Through an evaluation of a prototype implementation, we demonstrate that Sonata can support a wide range of network telemetry tasks with less state in the network, and lower data rates to streaming analytics systems, than current approaches can achieve.

  19. Photonics in switching: enabling technologies and subsystem design

    DEFF Research Database (Denmark)

    Vlachos, K.; Raffaelli, C.; Aleksic, S.

    2009-01-01

    This paper describes recent research activities and results in the area of photonic switching carried out within the framework of the EU-funded e-Photon/ONe + network of excellence, Virtual Department on Optical Switching. Technology aspects of photonics in switching and, in particular, recent...

  20. Report on detailed requirements for the INFLO prototype.

    Science.gov (United States)

    2013-12-01

    This report documents the System Requirements for the implementation of the Intelligent Network Flow Optimization (INFLO) : Prototype bundle within the Dynamic Mobility Applications (DMA) portion of the Connected Vehicle Program. It builds off of : t...

  1. Report on architecture description for the INFLO prototype.

    Science.gov (United States)

    2014-01-01

    This report documents the Architecture Description for the implementation of the Intelligent Network Flow Optimization : (INFLO) Prototype bundle within the Dynamic Mobility Applications (DMA) portion of the Connected Vehicle Program. The : intent is...

  2. FPGA Prototyping of RNN Decoder for Convolutional Codes

    National Research Council Canada - National Science Library

    Salcic, Zoran; Berber, Stevan; Secker, Paul

    2006-01-01

    This paper presents prototyping of a recurrent type neural network (RNN) convolutional decoder using system-level design specification and design flow that enables easy mapping to the target FPGA architecture...

  3. Next Generation Networks

    Directory of Open Access Journals (Sweden)

    Ladislav Schwartz

    2006-01-01

    Full Text Available Two network types had been existing in Slovakia by the end of the year 2004 – public switched telephone network – PSTN and packet switched data network – DCN. The other network, known as the next generation network – NGN, has been put into operation since the beginning of the year 2005. The role of the next generation network is to merge the both previous network types into one unified complex network with the full centralised control, based on routing and packet switching. The T-Com company (previous Slovak Telecom was the first who did it.

  4. A SOFT SWITCHED INTERLEAVED HIGH GAIN DC-DC CONVERTER

    Directory of Open Access Journals (Sweden)

    SHESHIDHAR REDDY ADDULA

    2017-09-01

    Full Text Available In this paper, a novel soft-switched interleaved DC-DC converter which provides a high voltage gain of 12 is proposed. Voltage gain of the basic interleaved boost converter is extended by using diode-capacitor multiplier (DCM cells. The switches are operated at a nominal duty ratio of 0.5. The voltage stress on the power switches and diodes is only a fraction of the output voltage. To enhance the operating power conversion efficiency, the switches are turned ON at zero voltage condition. Experimental results of 18-216V, 100W prototype converter validate the operating principle and the advantageous features of the presented converter.

  5. Analysis of RF MEMS Capacitive Switches by Using Switch EM ANN Models

    Directory of Open Access Journals (Sweden)

    Z. Marinković

    2015-11-01

    Full Text Available Artificial neural networks (ANNs have appeared to be an alternative to the conventional models of RF MEMS switches. In this paper, neural models of an RF MEMS capacitive switch are developed and used for the electrical design of the switch. Namely, an ANN model relating the switch resonant frequency and the bridge dimensions is used to analyze efficiently the switch behavior with changes of bridge dimensions. Furthermore, it is illustrated how the developed model can be used for the determination of bridge dimensions in order to achieve the desired switch resonant frequency. In addition, application of a switch inverse ANN model for the determination of bridge dimensions is analyzed as well.

  6. Power API Prototype

    Energy Technology Data Exchange (ETDEWEB)

    2014-12-04

    The software serves two purposes. The first purpose of the software is to prototype the Sandia High Performance Computing Power Application Programming Interface Specification effort. The specification can be found at http://powerapi.sandia.gov . Prototypes of the specification were developed in parallel with the development of the specification. Release of the prototype will be instructive to anyone who intends to implement the specification. More specifically, our vendor collaborators will benefit from the availability of the prototype. The second is in direct support of the PowerInsight power measurement device, which was co-developed with Penguin Computing. The software provides a cluster wide measurement capability enabled by the PowerInsight device. The software can be used by anyone who purchases a PowerInsight device. The software will allow the user to easily collect power and energy information of a node that is instrumented with PowerInsight. The software can also be used as an example prototype implementation of the High Performance Computing Power Application Programming Interface Specification.

  7. Decentralized Consistent Network Updates in SDN with ez-Segway

    KAUST Repository

    Nguyen, Thanh Dang

    2017-03-06

    We present ez-Segway, a decentralized mechanism to consistently and quickly update the network state while preventing forwarding anomalies (loops and black-holes) and avoiding link congestion. In our design, the centralized SDN controller only pre-computes information needed by the switches during the update execution. This information is distributed to the switches, which use partial knowledge and direct message passing to efficiently realize the update. This separation of concerns has the key benefit of improving update performance as the communication and computation bottlenecks at the controller are removed. Our evaluations via network emulations and large-scale simulations demonstrate the efficiency of ez-Segway, which compared to a centralized approach, improves network update times by up to 45% and 57% at the median and the 99th percentile, respectively. A deployment of a system prototype in a real OpenFlow switch and an implementation in P4 demonstrate the feasibility and low overhead of implementing simple network update functionality within switches.

  8. University of Tennessee deploys force10 switch for CERN work

    CERN Multimedia

    2007-01-01

    "Force20 networks, the pioneer in building and securing reliable networks, today announced that the University of Tennessee physics department has deployed the C300 resilient switch to analyze data form CERN's Large Hadron Collider." (1/2 page)

  9. From prototype to product

    DEFF Research Database (Denmark)

    Andersen, Tariq Osman; Bansler, Jørgen P.; Kensing, Finn

    2017-01-01

    This paper delves into the challenges of engaging patients, clinicians and industry stakeholders in the participatory design of an mHealth platform for patient-clinician collaboration. It follows the process from the development of a research prototype to a commercial software product. In particu......This paper delves into the challenges of engaging patients, clinicians and industry stakeholders in the participatory design of an mHealth platform for patient-clinician collaboration. It follows the process from the development of a research prototype to a commercial software product....... In particular, we draw attention to four major challenges of (a) aligning the different concerns of patients and clinicians, (b) designing according to clinical accountability, (c) ensuring commercial interest, and (d) dealing with regulatory constraints when prototyping safety critical health Information...

  10. arXiv The prototype of the HL-LHC magnets monitoring system based on Recurrent Neural Networks and adaptive quantization

    CERN Document Server

    Wielgosz, Maciej; Skoczeń, Andrzej

    This paper focuses on an examination of an applicability of Recurrent Neural Network models for detecting anomalous behavior of the CERN superconducting magnets. In order to conduct the experiments, the authors designed and implemented an adaptive signal quantization algorithm and a custom GRU-based detector and developed a method for the detector parameters selection. Three different datasets were used for testing the detector. Two artificially generated datasets were used to assess the raw performance of the system whereas the 231 MB dataset composed of the signals acquired from HiLumi magnets was intended for real-life experiments and model training. Several different setups of the developed anomaly detection system were evaluated and compared with state-of-the-art OC-SVM reference model operating on the same data. The OC-SVM model was equipped with a rich set of feature extractors accounting for a range of the input signal properties. It was determined in the course of the experiments that the detector, a...

  11. Designing a zero emissions power switch locomotive

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, J.; Hines, J. [National Instruments, Austin, TX (United States)

    2009-07-01

    In addition to providing electric power and drinking water in manned spacecraft, fuel cell power plants have provided safe, clean electric power to hospitals, universities and other facilities since the early 1990s. This paper described a zero emissions hydrogen and battery-powered hybrid switching locomotive designed for use in rail, port and military base applications. Designed in partnership with a consortium, the prototype hybrid switching locomotive is comprised of a number of proven commercial technologies and includes a control system developed by National Instruments. New applications for hydrogen fuel cell use in industrial vehicles were also discussed. The new design was scheduled for field testing at the end of 2008.

  12. Prototyping a Smart City

    DEFF Research Database (Denmark)

    Korsgaard, Henrik; Brynskov, Martin

    In this paper, we argue that by approaching the so-called Smart City as a design challenge, and an interaction design perspective, it is possible to both uncover existing challenges in the interplay between people, technology and society, as well as prototype possible futures. We present a case...... in which we exposed data about the online communication between the citizens and the municipality on a highly visible media facade, while at the same time prototyped a tool that enabled citizens to report ‘bugs’ within the city....

  13. Prototyping the Future

    Science.gov (United States)

    1998-01-01

    Advanced Ceramics Research (ACR) of Tucson, Arizona, researches transforming scientific concepts into technological achievement. Through the SBIR (Small Business Innovative Research) program, ACR developed a high pressure and temperature fused deposition system, a prototyping system that is known as extrusion freeform fabrication. This system is useful in manufacturing prosthetics. ACR also developed a three-dimensional rapid prototyping process in which physical models are quickly created directly from computer generated models. Marshall Space Flight Center also contracted ACR to fabricate a set of ceramic engines to be appraised for a solar thermal rocket engine test program.

  14. Prototyping Design and Business

    DEFF Research Database (Denmark)

    Rasmussen, Jørgen; Kramp, Gunnar; Schiønning Mortensen, Bo

    2011-01-01

    to ‘look into the future,’ to find unidentified opportunities through an open process and to validate their decisions through repeated prototyping. Management, on the other hand, is traditionally trained to ‘look into to the past’ and make decisions based on thoroughly analyzing existing information...... for collaboration and interdisciplinary development. Based on the thinking behind a prototype presentation the paper describes a specific case where the model is used in collaboration between a team of designers and the management of a medium-sized company....

  15. Portable Userspace Virtual Filesystem Switch

    Directory of Open Access Journals (Sweden)

    Łukasz Faber

    2013-01-01

    Full Text Available Multiple different filesystems — including disk-based, network, distributed, abstract — arean integral part of every operating system. They are usually written as kernel modules and abstracted to the user via a virtual filesystem switch. In this paper we analyse the feasibility of reimplementing the virtual filesystem switch as a userspace daemon and applicability of this approach in real-life usage. Such reimplementation will require a way to virtualise processes behaviour related to filesystem operations. The problem is non-trivial, as we assume limited capabilities of the VFS switch implemented in userspace. We present a layered architecture comprising of a monitoring process, the VFS abstraction and real filesystem implementations. All working in userspace. Then, we evaluate this solution in four areas: portability, feasibility, usability and performance. Our results demonstrate possible gains in using the userspace-based approach with monolithic kernels, but also underline problems that are encountered in this approach.

  16. Switched on!

    CERN Document Server

    2008-01-01

    Like a star arriving on stage, impatiently followed by each member of CERN personnel and by millions of eyes around the world, the first beam of protons has circulated in the LHC. After years in the making and months of increasing anticipation, today the work of hundreds of people has borne fruit. WELL DONE to all! Successfully steered around the 27 kilometres of the world’s most powerful particle accelerator at 10:28 this morning, this first beam of protons circulating in the ring marks a key moment in the transition from over two decades of preparation to a new era of scientific discovery. "It’s a fantastic moment," said the LHC project leader Lyn Evans, "we can now look forward to a new era of understanding about the origins and evolution of the universe". Starting up a major new particle accelerator takes much more than flipping a switch. Thousands of individual elements have to work in harmony, timings have to be synchronize...

  17. Prototype ATLAS straw tracker

    CERN Multimedia

    Laurent Guiraud

    1998-01-01

    This is an early prototype of the straw tracking device for the ATLAS detector at CERN. This detector will be part of the LHC project, scheduled to start operation in 2008. The straw tracker will consist of thousands of gas-filled straws, each containing a wire, allowing the tracks of particles to be followed.

  18. Surrogates-based prototyping

    NARCIS (Netherlands)

    Du Bois, E.; Horvath, I.

    2014-01-01

    The research is situated in the system development phase of interactive software products. In this detailed design phase, we found a need for fast testable prototyping to achieve qualitative change proposals on the system design. In this paper, we discuss a literature study on current software

  19. LEP vacuum chamber, prototype

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Final prototype for the LEP vacuum chamber, see 8305170 for more details. Here we see the strips of the NEG pump, providing "distributed pumping". The strips are made from a Zr-Ti-Fe alloy. By passing an electrical current, they were heated to 700 deg C.

  20. Rapid Prototyping in PVS

    Science.gov (United States)

    Munoz, Cesar A.; Butler, Ricky (Technical Monitor)

    2003-01-01

    PVSio is a conservative extension to the PVS prelude library that provides basic input/output capabilities to the PVS ground evaluator. It supports rapid prototyping in PVS by enhancing the specification language with built-in constructs for string manipulation, floating point arithmetic, and input/output operations.

  1. Rapid Prototyping Reconsidered

    Science.gov (United States)

    Desrosier, James

    2011-01-01

    Continuing educators need additional strategies for developing new programming that can both reduce the time to market and lower the cost of development. Rapid prototyping, a time-compression technique adapted from the high technology industry, represents one such strategy that merits renewed evaluation. Although in higher education rapid…

  2. Cost Effective Prototyping

    Science.gov (United States)

    Wickman, Jerry L.; Kundu, Nikhil K.

    1996-01-01

    This laboratory exercise seeks to develop a cost effective prototype development. The exercise has the potential of linking part design, CAD, mold development, quality control, metrology, mold flow, materials testing, fixture design, automation, limited parts production and other issues as related to plastics manufacturing.

  3. Combining optics and SDN to enable true hybrid integration of electronic and photonic switching solutions

    DEFF Research Database (Denmark)

    Guelbenzu, Gonzalo; Miao, Wang; Ben-Itzhak, Yaniv

    2017-01-01

    We present two hybrid fabrics integrating optical and electronic switches with SDN, and a novel approach improving the scaling of fast optical switches. C-Share reroute flows through optical switches increasing network performance. E-WDM exploits the optical switch transparency by emulating...

  4. Monolithic, High-Speed Fiber-Optic Switching Array for Lidar Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This NASA SBIR Phase II effort will develop a 1 x 10 prototype non-mechanical fiber optic switch for use with high power lasers. The proposed optical device is a...

  5. Software evolution in prototyping

    OpenAIRE

    Berzins, V.; Qi, Lu

    1996-01-01

    This paper proposes a model of software changes for supporting the evolution of software prototypes. The software evolution steps are decomposed into primitive substeps that correspond to monotonic specification changes. This structure is used to rearrange chronological derivation sequences into structures containing only meaning-preserving changes. The authors indicate how this structure can be used to automatically combine different changes to a specification. A set of examples illustrates ...

  6. A prototype analysis of vengeance

    NARCIS (Netherlands)

    Elshout, Maartje; Nelissen, Rob; van Beest, Ilja

    2015-01-01

    The authors examined the concept of vengeance from a prototype perspective. In 6 studies, the prototype structure of vengeance was mapped. Sixty-nine features of vengeance were identified (Study 1), and rated on centrality (Study 2). Further studies confirmed the prototype structure. Compared to

  7. MITRE sensor layer prototype

    Science.gov (United States)

    Duff, Francis; McGarry, Donald; Zasada, David; Foote, Scott

    2009-05-01

    The MITRE Sensor Layer Prototype is an initial design effort to enable every sensor to help create new capabilities through collaborative data sharing. By making both upstream (raw) and downstream (processed) sensor data visible, users can access the specific level, type, and quantities of data needed to create new data products that were never anticipated by the original designers of the individual sensors. The major characteristic that sets sensor data services apart from typical enterprise services is the volume (on the order of multiple terabytes) of raw data that can be generated by most sensors. Traditional tightly coupled processing approaches extract pre-determined information from the incoming raw sensor data, format it, and send it to predetermined users. The community is rapidly reaching the conclusion that tightly coupled sensor processing loses too much potentially critical information.1 Hence upstream (raw and partially processed) data must be extracted, rapidly archived, and advertised to the enterprise for unanticipated uses. The authors believe layered sensing net-centric integration can be achieved through a standardize-encapsulate-syndicateaggregate- manipulate-process paradigm. The Sensor Layer Prototype's technical approach focuses on implementing this proof of concept framework to make sensor data visible, accessible and useful to the enterprise. To achieve this, a "raw" data tap between physical transducers associated with sensor arrays and the embedded sensor signal processing hardware and software has been exploited. Second, we encapsulate and expose both raw and partially processed data to the enterprise within the context of a service-oriented architecture. Third, we advertise the presence of multiple types, and multiple layers of data through geographic-enabled Really Simple Syndication (GeoRSS) services. These GeoRSS feeds are aggregated, manipulated, and filtered by a feed aggregator. After filtering these feeds to bring just the type

  8. Latching micro optical switch

    Science.gov (United States)

    Garcia, Ernest J; Polosky, Marc A

    2013-05-21

    An optical switch reliably maintains its on or off state even when subjected to environments where the switch is bumped or otherwise moved. In addition, the optical switch maintains its on or off state indefinitely without requiring external power. External power is used only to transition the switch from one state to the other. The optical switch is configured with a fixed optical fiber and a movable optical fiber. The movable optical fiber is guided by various actuators in conjunction with a latching mechanism that configure the switch in one position that corresponds to the on state and in another position that corresponds to the off state.

  9. Tutorial: Integrated-photonic switching structures

    Science.gov (United States)

    Soref, Richard

    2018-02-01

    Recent developments in waveguided 2 × 2 and N × M photonic switches are reviewed, including both broadband and narrowband resonant devices for the Si, InP, and AlN platforms. Practical actuation of switches by electro-optical and thermo-optical techniques is discussed. Present datacom-and-computing applications are reviewed, and potential applications are proposed for chip-scale photonic and optoelectronic integrated switching networks. Potential is found in the reconfigurable, programmable "mesh" switches that enable a promising group of applications in new areas beyond those in data centers and cloud servers. Many important matrix switches use gated semiconductor optical amplifiers. The family of broadband, directional-coupler 2 × 2 switches featuring two or three side-coupled waveguides deserves future experimentation, including devices that employ phase-change materials. The newer 2 × 2 resonant switches include standing-wave resonators, different from the micro-ring traveling-wave resonators. The resonant devices comprise nanobeam interferometers, complex-Bragg interferometers, and asymmetric contra-directional couplers. Although the fast, resonant devices offer ultralow switching energy, ˜1 fJ/bit, they have limitations. They require several trade-offs when deployed, but they do have practical application.

  10. A novel unipolar converter for switched reluctance motor

    Science.gov (United States)

    Le-Huy, Hoang; Viarouge, Philippe; Francoeur, Bruno

    1990-10-01

    A configuration of a unipolar converter with improved switching performance suitable for switched-reluctance motor supply is presented. The switched-reluctance motor operation principle is presented, and its ideal characteristics are considered. The proposed converter is described, and its operation is analyzed. The converter characteristics are studied with the aid of computer simulation. Current control of the proposed converter is considered. A prototype converter has been built to verify the analysis results and to validate the simulation. The design procedure is presented, and experimental results which confirm the analysis are given and discussed.

  11. Optical Switching and Bit Rates of 40 Gbit/s and above

    DEFF Research Database (Denmark)

    Ackaert, A.; Demester, P.; O'Mahony, M.

    2003-01-01

    Optical switching in WDM networks introduces additional aspects to the choice of single channel bit rates compared to WDM transmission systems. The mutual impact of optical switching and bit rates of 40 Gbps and above is discussed....

  12. Prototypes as Platforms for Participation

    DEFF Research Database (Denmark)

    Horst, Willem

    The development of interactive products in industry is an activity involving different disciplines – such as different kinds of designers, engineers, marketers and managers – in which prototypes play an important role. On the one hand, prototypes can be powerful boundary objects and an effective.......g. interaction designers, are in a position to design it in a way that enables and encourages different stakeholders to take ownership over it. This dissertation consists of a collection of five papers in which I introduce a collaborative approach to prototyping, and describe how designers can design prototypes...... of prototyping, and develop a sense of ownership over the prototype. This has several benefits for the interaction designer. Since participants learn about the design space and limitations of the prototype, they are able to give specific feedback and input, which the interaction designer can implement. Moreover...

  13. Multiuser switched diversity scheduling schemes

    KAUST Repository

    Shaqfeh, Mohammad

    2012-09-01

    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback systems in Rayleigh fading conditions. © 2012 IEEE.

  14. Prototyping Augmented Reality

    CERN Document Server

    Mullen, Tony

    2011-01-01

    Learn to create augmented reality apps using Processing open-source programming language Augmented reality (AR) is used all over, and you may not even realize it. Smartphones overlay data onto live camera views to show homes for sale, restaurants, or historical sites. American football broadcasts use AR to show the invisible first-down line on the field to TV viewers. Nike and Budweiser, among others, have used AR in ads. Now, you can learn to create AR prototypes using 3D data, Processing open-source programming language, and other languages. This unique book is an easy-to-follow guide on how

  15. AMS Prototyping Activities

    Science.gov (United States)

    Burleigh, Scott

    2008-01-01

    This slide presentation reviews the activity around the Asynchronous Message Service (AMS) prototype. An AMS reference implementation has been available since late 2005. It is aimed at supporting message exchange both in on-board environments and over space links. The implementation incoroporates all mandatory elements of the draft recommendation from July 2007: (1) MAMS, AMS, and RAMS protocols. (2) Failover, heartbeats, resync. (3) "Hooks" for security, but no cipher suites included in the distribution. The performance is reviewed, and a Benchmark latency test over VxWorks Message Queues is shown as histograms of a count vs microseconds per 1000-byte message

  16. Nightshade Prototype Experiments (Silverleaf)

    Energy Technology Data Exchange (ETDEWEB)

    Danielson, Jeremy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bauer, Amy L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-23

    The Red Sage campaign is a series of subcritical dynamic plutonium experiments designed to measure ejecta. Nightshade, the first experiments in Red Sage scheduled for fiscal year 2019, will measure the amount of ejecta emission into vacuum from a double-­shocked plutonium surface. To address the major technical risks in Nightshade, a Level 2 milestone was developed for fiscal year 2016. Silverleaf, a series of four experiments, was executed at the Los Alamos National Laboratory in July and August 2016 to demonstrate a prototype of the Nightshade package and to satisfy this Level 2 milestone. This report is documentation that Red Sage Level 2 milestone requirements were successfully met.

  17. Controller Architectures for Switching

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2009-01-01

    This paper investigate different controller architectures in connection with controller switching. The controller switching is derived by using the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization. A number of different architectures for the implementation of the YJBK parameterization...... are described and applied in connection with controller switching. An architecture that does not include inversion of the coprime factors is introduced. This architecture will make controller switching particular simple....

  18. Remote switch actuator

    Science.gov (United States)

    Haas, Edwin Gerard; Beauman, Ronald; Palo, Jr., Stefan

    2013-01-29

    The invention provides a device and method for actuating electrical switches remotely. The device is removably attached to the switch and is actuated through the transfer of a user's force. The user is able to remain physically removed from the switch site obviating need for protective equipment. The device and method allow rapid, safe actuation of high-voltage or high-current carrying electrical switches or circuit breakers.

  19. Perancangan Switch Matrik Besar Menggunakan Array Switch Analog Zarlink

    OpenAIRE

    M. Zulfin

    2009-01-01

    Secara tradisional, perancangan sebuah switch matrik yang besar dilakukan dengan menggunakan switch-switch elektromekanik. Dengan demikian, banyak bagian yang bergerak yang digunakan untuk membangun switch matrik ini. Dengan kemajuan bidang elektronik, switch elektromekanik saat ini dapat digantikan dengan switch-switch semikonduktor yang ekivalen yang menawarkan solusi yang lebih ekonomis dan memiliki keandalan yang lebih baik. Rumpun switch crosspoint analog Zarlink dapat disusun dengan mud...

  20. Dwell-time switching

    NARCIS (Netherlands)

    Cao, Ming; Morse, A. Stephen

    Dwell-time switching is a logic for orchestrating the switching between controllers in a family of candidate controllers in order to control a process with a highly uncertain model. An analysis is given of dwell-time switching which is appropriate to a variety of control problems in which the class

  1. MATHEMATIC SIMULATION OF TRANSIENT PROCESS IN A. C – SYSTEM “ELECTRIC – TRACTION – NETWORK – LOCOMOTIVE” 2. SWITCH ON THE MAIN LOCOMOTIVE’S POWER CONVERTER IN “FREE PAY” MODE; DEFINITION AND ANALYSIS CURRENT SURGE OF MAGNETIZATION

    Directory of Open Access Journals (Sweden)

    T. M. Mischenko

    2010-12-01

    Full Text Available The article is a continuation of analysis of mathematical models for AC systems, in which the elements of electric-traction network and switch-on of power transformer in an idling mode are gradually connected. The numerical calculations and analysis of current of transformer magnetization are executed.

  2. Design of a Clap Activated Switch

    Directory of Open Access Journals (Sweden)

    Seyi Stephen OLOKEDE

    2008-12-01

    Full Text Available This paper presents the design of a clap activated switch device that will serve well in different phono-controlled applications, providing inexpensive key and at the same time flee from false triggering.This involves the design of various sages consisting of the pickup transducer, low frequency, audio low power and low noise amplifier, timer, bistable and switches. It also consists of special network components to prevent false triggering and ensure desired performance objectives. A decade counter IC serves the bistable function instead of flip-flop, special transistor and edge triggering network for low audio frequency.

  3. Coded Network Function Virtualization

    DEFF Research Database (Denmark)

    Al-Shuwaili, A.; Simone, O.; Kliewer, J.

    2016-01-01

    Network function virtualization (NFV) prescribes the instantiation of network functions on general-purpose network devices, such as servers and switches. While yielding a more flexible and cost-effective network architecture, NFV is potentially limited by the fact that commercial off-the-shelf ha......Network function virtualization (NFV) prescribes the instantiation of network functions on general-purpose network devices, such as servers and switches. While yielding a more flexible and cost-effective network architecture, NFV is potentially limited by the fact that commercial off...

  4. DataCollection Prototyping

    CERN Multimedia

    Beck, H.P.

    DataCollection is a subsystem of the Trigger, DAQ & DCS project responsible for the movement of event data from the ROS to the High Level Triggers. This includes data from Regions of Interest (RoIs) for Level 2, building complete events for the Event Filter and finally transferring accepted events to Mass Storage. It also handles passing the LVL1 RoI pointers and the allocation of Level 2 processors and load balancing of Event Building. During the last 18 months DataCollection has developed a common architecture for the hardware and software required. This involved a radical redesign integrating ideas from separate parts of earlier TDAQ work. An important milestone for this work, now achieved, has been to demonstrate this subsystem in the so-called Phase 2A Integrated Prototype. This prototype comprises the various TDAQ hardware and software components (ROSs, LVL2, etc.) under the control of the TDAQ Online software. The basic functionality has been demonstrated on small testbeds (~8-10 processing nodes)...

  5. Live Piloting and Prototyping

    Directory of Open Access Journals (Sweden)

    Francesca Rizzo

    2013-07-01

    Full Text Available This paper presents current trends in service design research concerning large scale projects aimed at generating changes at a local scale. The strategy adopted to achieve this, is to co-design solutions including future users in the development process, prototyping and testing system of products and services before their actual implementation. On the basis of experience achieved in the European Project Life 2.0, this paper discusses which methods and competencies are applied in the development of these projects, eliciting the lessons learnt especially from the piloting phase in which the participatory design (PD approach plays a major role. In the first part, the topic is introduced jointly with the theoretical background where the user center design and participatory design methods are presented; then the Life 2.0 project development is described; finally the experience is discussed from a service design perspective, eliciting guidelines for piloting and prototyping services in a real context of use. The paper concludes reflecting on the designers’ role and competencies needed in this process.

  6. Prototype of a transient waveform recording ASIC

    Science.gov (United States)

    Qin, J.; Zhao, L.; Cheng, B.; Chen, H.; Guo, Y.; Liu, S.; An, Q.

    2018-01-01

    The paper presents the design and measurement results of a transient waveform recording ASIC based on the Switched Capacitor Array (SCA) architecture. This 0.18 μm CMOS prototype device contains two channels and each channel employs a SCA of 128 samples deep, a 12-bit Wilkinson ADC and a serial data readout. A series of tests have been conducted and the results indicate that: a full 1 V signal voltage range is available, the input analog bandwidth is approximately 450 MHz and the sampling speed is adjustable from 0.076 to 3.2 Gsps (Gigabit Samples Per Second). For precision waveform timing extraction, careful calibration of timing intervals between samples is conducted to improve the timing resolution of such chips, and the timing precision of this ASIC is proved to be better than 15 ps RMS.

  7. Network Warrior

    CERN Document Server

    Donahue, Gary

    2011-01-01

    Pick up where certification exams leave off. With this practical, in-depth guide to the entire network infrastructure, you'll learn how to deal with real Cisco networks, rather than the hypothetical situations presented on exams like the CCNA. Network Warrior takes you step by step through the world of routers, switches, firewalls, and other technologies based on the author's extensive field experience. You'll find new content for MPLS, IPv6, VoIP, and wireless in this completely revised second edition, along with examples of Cisco Nexus 5000 and 7000 switches throughout. Topics include: An

  8. SXI prototype mirror mount

    Science.gov (United States)

    1995-04-01

    The purpose of this contract was to provide optomechanical engineering and fabrication support to the Solar X-ray Imager (SXI) program in the areas of mirror, optical bench and camera assemblies of the telescope. The Center for Applied Optics (CAO) worked closely with the Optics and S&E technical staff of MSFC to develop and investigate the most viable and economical options for the design and fabrication of a number of parts for the various telescope assemblies. All the tasks under this delivery order have been successfully completed within budget and schedule. A number of development hardware parts have been designed and fabricated jointly by MSFC and UAH for the engineering model of SXI. The major parts include a nickel electroformed mirror and a mirror mount, plating and coating of the ceramic spacers, and gold plating of the contact rings and fingers for the camera assembly. An aluminum model of the high accuracy sun sensor (HASS) was also designed and fabricated. A number of fiber optic tapers for the camera assembly were also coated with indium tin oxide and phosphor for testing and evaluation by MSFC. A large number of the SXI optical bench parts were also redesigned and simplified for a prototype telescope. These parts include the forward and rear support flanges, front aperture plate, the graphite epoxy optical bench and a test fixture for the prototype telescope. More than fifty (50) drawings were generated for various components of the prototype telescope. Some of these parts were subsequently fabricated at UAH machine shop or at MSFC or by the outside contractors. UAH also provide technical support to MSFC staff for a number of preliminary and critical design reviews. These design reviews included PDR and CDR for the mirror assembly by United Technologies Optical Systems (UTOS), and the program quarterly reviews, and SXI PDR and CDR. UAH staff also regularly attended the monthly status reviews, and made a significant number of suggestions to improve

  9. SXI prototype mirror mount

    Science.gov (United States)

    1995-01-01

    The purpose of this contract was to provide optomechanical engineering and fabrication support to the Solar X-ray Imager (SXI) program in the areas of mirror, optical bench and camera assemblies of the telescope. The Center for Applied Optics (CAO) worked closely with the Optics and S&E technical staff of MSFC to develop and investigate the most viable and economical options for the design and fabrication of a number of parts for the various telescope assemblies. All the tasks under this delivery order have been successfully completed within budget and schedule. A number of development hardware parts have been designed and fabricated jointly by MSFC and UAH for the engineering model of SXI. The major parts include a nickel electroformed mirror and a mirror mount, plating and coating of the ceramic spacers, and gold plating of the contact rings and fingers for the camera assembly. An aluminum model of the high accuracy sun sensor (HASS) was also designed and fabricated. A number of fiber optic tapers for the camera assembly were also coated with indium tin oxide and phosphor for testing and evaluation by MSFC. A large number of the SXI optical bench parts were also redesigned and simplified for a prototype telescope. These parts include the forward and rear support flanges, front aperture plate, the graphite epoxy optical bench and a test fixture for the prototype telescope. More than fifty (50) drawings were generated for various components of the prototype telescope. Some of these parts were subsequently fabricated at UAH machine shop or at MSFC or by the outside contractors. UAH also provide technical support to MSFC staff for a number of preliminary and critical design reviews. These design reviews included PDR and CDR for the mirror assembly by United Technologies Optical Systems (UTOS), and the program quarterly reviews, and SXI PDR and CDR. UAH staff also regularly attended the monthly status reviews, and made a significant number of suggestions to improve

  10. Experimental Validation of Modelled Fluid Forces in Fast Switching Hydraulic On/Off Valves

    DEFF Research Database (Denmark)

    Nørgård, Christian; Bech, Michael Møller; Roemer, Daniel Beck

    2015-01-01

    A prototype of a fast switching valve for a digital hydraulic machine has been designed and manufactured. The valve is composed of an annular seat plunger connected with a moving coil actuator as the force producing element. The valve prototype is designed for flow rates of 600 l/min with less than...... approaches the closed position. Fast switching is essential for digital hydraulic machines to achieve a high efficiency. As the fluid forces influences the response obtaining an accurate model is important. To validate the model tests are carried out on the prototype where the valve is closed, both...

  11. Architectural Prototyping in Industrial Practice

    DEFF Research Database (Denmark)

    Christensen, Henrik Bærbak; Hansen, Klaus Marius

    2008-01-01

    , in addressing issues regarding quality attributes, in addressing architectural risks, and in addressing the problem of knowledge transfer and conformance. Little work has been reported so far on the actual industrial use of architectural prototyping. In this paper, we report from an ethnographical study...... prototypes include end-user or business related functionality rather than purely architectural functionality. Based on these observations we provide recommendations for effective industrial architectural prototyping....

  12. Prototyping user displays using CLIPS

    Science.gov (United States)

    Kosta, Charles P.; Miller, Ross; Krolak, Patrick; Vesty, Matt

    1990-01-01

    CLIPS is being used as an integral module of a rapid prototyping system. The prototyping system consists of a display manager for object browsing, a graph program for displaying line and bar charts, and a communications server for routing messages between modules. A CLIPS simulation of a physical model provides dynamic control of the user's display. Currently, a project is well underway to prototype the Advanced Automation System (AAS) for the Federal Aviation Administration.

  13. Neural correlates for task switching in the macaque superior colliculus.

    Science.gov (United States)

    Chan, Jason L; Koval, Michael J; Johnston, Kevin; Everling, Stefan

    2017-10-01

    Successful task switching requires a network of brain areas to select, maintain, implement, and execute the appropriate task. Although frontoparietal brain areas are thought to play a critical role in task switching by selecting and encoding task rules and exerting top-down control, how brain areas closer to the execution of tasks participate in task switching is unclear. The superior colliculus (SC) integrates information from various brain areas to generate saccades and is likely influenced by task switching. Here, we investigated switch costs in nonhuman primates and their neural correlates in the activity of SC saccade-related neurons in monkeys performing cued, randomly interleaved pro- and anti-saccade trials. We predicted that behavioral switch costs would be associated with differential modulations of SC activity in trials on which the task was switched vs. repeated, with activity on the current trial resembling that associated with the task set of the previous trial when a switch occurred. We observed both error rate and reaction time switch costs and changes in the discharge rate and timing of activity in SC neurons between switch and repeat trials. These changes were present later in the task only after fixation on the cue stimuli but before saccade onset. These results further establish switch costs in macaque monkeys and suggest that SC activity is modulated by task-switching processes in a manner inconsistent with the concept of task set inertia.NEW & NOTEWORTHY Task-switching behavior and superior colliculus (SC) activity were investigated in nonhuman primates performing randomly interleaved pro- and anti-saccade tasks. Here, we report error rate and reaction time switch costs in macaque monkeys and associated differences in stimulus-related activity of saccade-related neurons in the SC. These results provide a neural correlate for task switching and suggest that the SC is modulated by task-switching processes and may reflect the completion of task

  14. Prototype Stilbene Neutron Collar

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, M. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shumaker, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Snyderman, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Verbeke, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wong, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-26

    A neutron collar using stilbene organic scintillator cells for fast neutron counting is described for the assay of fresh low enriched uranium (LEU) fuel assemblies. The prototype stilbene collar has a form factor similar to standard He-3 based collars and uses an AmLi interrogation neutron source. This report describes the simulation of list mode neutron correlation data on various fuel assemblies including some with neutron absorbers (burnable Gd poisons). Calibration curves (doubles vs 235U linear mass density) are presented for both thermal and fast (with Cd lining) modes of operation. It is shown that the stilbene collar meets or exceeds the current capabilities of He-3 based neutron collars. A self-consistent assay methodology, uniquely suited to the stilbene collar, using triples is described which complements traditional assay based on doubles calibration curves.

  15. The MONOLITH prototype

    CERN Document Server

    Ambrosio, M; Bencivenni, G; Candela, A M; Chiarini, A; Chignoli, F; De Deo, M; D'Incecco, M; Gerli, S; Giusti, P; Gómez, F; Gustavino, C; Lindozzi, M; Mannocchi, G; Menghetti, H; Morello, C; Murtas, F; Paoluzzi, G; Pilastrini, R; Redaelli, N G; Santoni, M; Sartorelli, G; Terranova, F; Trinchero, G C

    2000-01-01

    MONOLITH (Massive Observatory for Neutrino Oscillation or LImits on THeir existence) is the project of an experiment to study atmospheric neutrino oscillations with a massive magnetized iron detector. The baseline option is a 34 kt iron detector based on the use of about 50000 m/sup 2/ of the glass Resistive Plate Chambers (glass RPCs) developed at the Laboratori Nazionali del Gran Sasso (LNGS). An 8 ton prototype equipped with 23 m/sup 2/ of glass RPC has been realized and tested at the T7-PS beam at CERN. The energy resolution for pions follows a 68%/ square root (E(GeV))+2% law for orthogonally incident particles, in the energy range between 2 and 10 GeV. The time resolution and the tracking capability of the glass RPC are suitable for the MONOLITH experiment. (7 refs).

  16. Naval Prototype Optical Interferometer (NPOI)

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Used for astrometry and astronomical imaging, the Naval Prototype Optical Interferometer (NPOI) is a distributed aperture optical telescope. It is operated...

  17. Mobile prototyping with Axure 7

    CERN Document Server

    Hacker, Will

    2013-01-01

    This book is a step-by-step tutorial which includes hands-on examples and downloadable Axure files to get you started with mobile prototyping immediately. You will learn how to develop an application from scratch, and will be guided through each and every step.If you are a mobile-centric developer/designer, or someone who would like to take their Axure prototyping skills to the next level and start designing and testing mobile prototypes, this book is ideal for you. You should be familiar with prototyping and Axure specifically, before you read this book.

  18. FAS: Using FPGA to Accelerate and Secure SDN Software Switches

    Directory of Open Access Journals (Sweden)

    Wenwen Fu

    2018-01-01

    Full Text Available Software-Defined Networking (SDN promises the vision of more flexible and manageable networks but requires certain level of programmability in the data plane to accommodate different forwarding abstractions. SDN software switches running on commodity multicore platforms are programmable and are with low deployment cost. However, the performance of SDN software switches is not satisfactory due to the complex forwarding operations on packets. Moreover, this may hinder the performance of real-time security on software switch. In this paper, we analyze the forwarding procedure and identify the performance bottleneck of SDN software switches. An FPGA-based mechanism for accelerating and securing SDN switches, named FAS (FPGA-Accelerated SDN software switch, is proposed to take advantage of the reconfigurability and high-performance advantages of FPGA. FAS improves the performance as well as the capacity against malicious traffic attacks of SDN software switches by offloading some functional modules. We validate FAS on an FPGA-based network processing platform. Experiment results demonstrate that the forwarding rate of FAS can be 44% higher than the original SDN software switch. In addition, FAS provides new opportunity to enhance the security of SDN software switches by allowing the deployment of bump-in-the-wire security modules (such as packet detectors and filters in FPGA.

  19. Photonics in switching: Architectures, systems and enabling technologies

    DEFF Research Database (Denmark)

    Raffaelli, C.; Vlachos, K.; Andriolli, N.

    2008-01-01

    This paper describes recent research activities and results in the area of photonic switching carried out within the Virtual Department on Switching (VDS) of the European e-Photon/ONe Network of Excellence. Contributions from outstanding European research groups in this field are collected to offer...

  20. All-optical processing with molecular switches

    OpenAIRE

    Raymo, Françisco M.; Giordani, Silvia

    2002-01-01

    A gradual transition from electrical to optical networks is accompanying the rapid progress of telecommunication technology. The urge for enhanced transmission capacity and speed is dictating this trend. In fact, large volumes of data encoded on optical signals can be transported rapidly over long distances. Their propagation along specific routes across a communication network is ensured by a combination of optical fibers and optoelectronic switches. It is becoming appar...

  1. Magnonic interferometric switch for multi-valued logic circuits

    Science.gov (United States)

    Balynsky, Michael; Kozhevnikov, Alexander; Khivintsev, Yuri; Bhowmick, Tonmoy; Gutierrez, David; Chiang, Howard; Dudko, Galina; Filimonov, Yuri; Liu, Guanxiong; Jiang, Chenglong; Balandin, Alexander A.; Lake, Roger; Khitun, Alexander

    2017-01-01

    We investigated a possible use of the magnonic interferometric switches in multi-valued logic circuits. The switch is a three-terminal device consisting of two spin channels where input, control, and output signals are spin waves. Signal modulation is achieved via the interference between the source and gate spin waves. We report experimental data on a micrometer scale prototype based on the Y3Fe2(FeO4)3 structure. The output characteristics are measured at different angles of the bias magnetic field. The On/Off ratio of the prototype exceeds 13 dB at room temperature. Experimental data are complemented by the theoretical analysis and the results of micro magnetic simulations showing spin wave propagation in a micrometer size magnetic junction. We also present the results of numerical modeling illustrating the operation of a nanometer-size switch consisting of just 20 spins in the source-drain channel. The utilization of spin wave interference as a switching mechanism makes it possible to build nanometer-scale logic gates, and minimize energy per operation, which is limited only by the noise margin. The utilization of phase in addition to amplitude for information encoding offers an innovative route towards multi-state logic circuits. We describe possible implementation of the three-value logic circuits based on the magnonic interferometric switches. The advantages and shortcomings inherent in interferometric switches are also discussed.

  2. Microprocessor Controlled Capacitor Bank Switching System for ...

    African Journals Online (AJOL)

    In this work, analysis and development of a microprocessor controlled capacitor bank switching system for deployment in a smart distribution network was carried out. This system was implemented by the use of discreet components such as resistors, capacitors, transistor, diode, automatic voltage regulator, with the ...

  3. Switches and Bridges - Comparison and Contrast

    OpenAIRE

    Marian M. Pope

    2017-01-01

    This paper presents a comparison and contrast of switches and bridges. The paper discusses the Open Systems Interconnection (OSI) model for the layers used by the devices. The intelligence and specific functions of each device are also mentioned. The paper also presents the location of each device in a network

  4. Saturated Switching Systems

    CERN Document Server

    Benzaouia, Abdellah

    2012-01-01

    Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

  5. Y-source impedance-network-based isolated boost DC/DC converter

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Town, Graham; Loh, Poh Chiang

    2014-01-01

    A dc-dc converter with very high voltage gain is proposed in this paper for any medium-power application requiring a high voltage boost with galvanic isolation. The proposed converter topology can be realized using only two switches. With this topology a very high voltage boost can be achieved even...... with a relatively low duty cycle of the switches, and the gain obtainable is presently not matched by any existing impedance network based converter operated at the same duty ratio. The proposed converter has a Y-source impedance network to boost the voltage at the intermediate dc-link side and a push......-pull transformer for square-wave AC inversion and isolation. The voltage-doubler rectifier provides a constant dc voltage at the output stage. A theoretical analysis of the converter is presented, supported by simulation and experimental results. A 250 W down-scaled prototype was implemented in the laboratory...

  6. Window prototypes during the project

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe

    1996-01-01

    The conditions for the PASSYS test and the results of the measurements on one of the aerogel window prototypes are described.......The conditions for the PASSYS test and the results of the measurements on one of the aerogel window prototypes are described....

  7. Rapid prototyping in medical sciences

    Directory of Open Access Journals (Sweden)

    Ákos Márk Horváth

    2015-09-01

    Full Text Available Even if it sound a bit incredible rapid prototyping (RPT as production method has been used for decades in other professions. Nevertheless medical science just started discover the possibilities of this technology and use the offered benefits of 3D printing. In this paper authors have investigated the pharmaceutical usage of rapid prototyping.

  8. LISA phasemeter development: Advanced prototyping

    Energy Technology Data Exchange (ETDEWEB)

    Bykov, Iouri; Delgado, Juan Jose Esteban; Garcia Marin, Antonio Francisco; Heinzel, Gerhard; Danzmann, Karsten, E-mail: Iouri.bykov@aei.mpg.d [Institute for Gravitational Physics of the Leibniz University Hannover and Max Planck Institute for Gravitational Physics (Albert Einstein Institute) (Germany)

    2009-03-01

    We present the status of our investigations on the LISA Phasemeter. The new prototype is based on a custom-designed breadboard with four high-speed ADC and two DAC channels, extended readout capabilities and a large FPGA (field programmable gate array). The required main functionalities and performance of the prototype have been demonstrated in laboratory conditions.

  9. FreeSWITCH Cookbook

    CERN Document Server

    Minessale, Anthony

    2012-01-01

    This is a problem-solution approach to take your FreeSWITCH skills to the next level, where everything is explained in a practical way. If you are a system administrator, hobbyist, or someone who uses FreeSWITCH on a regular basis, this book is for you. Whether you are a FreeSWITCH expert or just getting started, this book will take your skills to the next level.

  10. Emergence of phenotype switching through continuous and discontinuous evolutionary transitions

    Science.gov (United States)

    Patra, Pintu; Klumpp, Stefan

    2015-07-01

    Bacterial persistence (phenotypic tolerance to antibiotics) provides a prime example of bet-hedging, where normally growing cells generate slow-growing but antibiotic-tolerant persister cells to survive through periods of exposure to antibiotics. The population dynamics of persistence is explained by a phenotype switching mechanism that allows individual cells to switch between these different cellular states with different environmental sensitivities. Here, we perform a theoretical study based on an exact solution for the case of a periodic variation of the environment to address how phenotype switching emerges and under what conditions switching is or is not beneficial for long-time growth. Specifically we report a bifurcation through which a fitness maximum and minimum emerge above a threshold in the duration of exposure to the antibiotic. Only above this threshold, the optimal phenotype switching rates are adjusted to the time scales of the environment, as emphasized by previous theoretical studies, while below the threshold a non-switching population is fitter than a switching one. The bifurcation can be of different type, depending on how the phenotype switching rates are allowed to vary. If the switching rates for both directions of the switch are coupled, the transition is discontinuous and results in evolutionary hysteresis, which we confirm with a stochastic simulation. If the switching rates vary individually, a continuous transition is obtained and no hysteresis is found. We discuss how both scenarios can be linked to changes in the underlying molecular networks.

  11. Behavioral plasticity through the modulation of switch neurons.

    Science.gov (United States)

    Vassiliades, Vassilis; Christodoulou, Chris

    2016-02-01

    A central question in artificial intelligence is how to design agents capable of switching between different behaviors in response to environmental changes. Taking inspiration from neuroscience, we address this problem by utilizing artificial neural networks (NNs) as agent controllers, and mechanisms such as neuromodulation and synaptic gating. The novel aspect of this work is the introduction of a type of artificial neuron we call "switch neuron". A switch neuron regulates the flow of information in NNs by selectively gating all but one of its incoming synaptic connections, effectively allowing only one signal to propagate forward. The allowed connection is determined by the switch neuron's level of modulatory activation which is affected by modulatory signals, such as signals that encode some information about the reward received by the agent. An important aspect of the switch neuron is that it can be used in appropriate "switch modules" in order to modulate other switch neurons. As we show, the introduction of the switch modules enables the creation of sequences of gating events. This is achieved through the design of a modulatory pathway capable of exploring in a principled manner all permutations of the connections arriving on the switch neurons. We test the model by presenting appropriate architectures in nonstationary binary association problems and T-maze tasks. The results show that for all tasks, the switch neuron architectures generate optimal adaptive behaviors, providing evidence that the switch neuron model could be a valuable tool in simulations where behavioral plasticity is required. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Role model and prototype matching

    DEFF Research Database (Denmark)

    Lykkegaard, Eva; Ulriksen, Lars

    2016-01-01

    Previous research has found that young people’s prototypes of science students and scientists affect their inclination to choose tertiary STEM programs (Science, Technology, Engineering and Mathematics). Consequently, many recruitment initiatives include role models to challenge these prototypes......’ meetings with the role models affected their thoughts concerning STEM students and attending university. The regular self-to-prototype matching process was shown in real-life role-models meetings to be extended to a more complex three-way matching process between students’ self-perceptions, prototype...... images and situation-specific conceptions of role models. Furthermore, the study underlined the positive effect of prolonged role-model contact, the importance of using several role models and that traditional school subjects catered more resistant prototype images than unfamiliar ones did...

  13. ITER prototype fast plant system controller

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, B., E-mail: bruno@ipfn.ist.utl.pt [Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, P-1049-001 Lisboa (Portugal); Sousa, J.; Carvalho, B.B.; Rodrigues, A.P.; Correia, M.; Batista, A. [Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, P-1049-001 Lisboa (Portugal); Vega, J. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, CIEMAT, Av. Complutense, Madrid (Spain); Ruiz, M.; Lopez, J.M. [Grupo de Investigacion en Instrumentacion y Acustica Aplicada, Universidad Politecnica de Madrid (Spain); Castro, R. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, CIEMAT, Av. Complutense, Madrid (Spain); Wallander, A.; Utzel, N.; Makijarvi, P.; Simrock, S. [ITER Organization, CS 90 046, 13067 St. Paul lez Durance Cedex (France); Neto, A.; Alves, D.; Valcarcel, D.F. [Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, P-1049-001 Lisboa (Portugal); Lousa, P.; Piedade, F.; Fernandes, L. [INOV, Lisbon (Portugal)

    2011-10-15

    ITER CODAC Design identified the need for slow and fast control plant systems, based respectively on industrial automation technology with maximum sampling rates below 100 Hz, and on embedded technology with higher sampling rates and more stringent real-time requirements. The fast system is applicable to diagnostics and plant systems in closed-control loops whose cycle times are below 1 ms. Fast controllers will be dedicated industrial controllers with the ability to supervise other fast and/or slow controllers, interface to actuators and sensors and high performance networks (HPN). This contribution presents the engineering design of two prototypes of a fast plant system controller (FPSC), specialized for data acquisition, constrained by ITER technological choices. This prototyping activity contributes to the Plant Control Design Handbook (PCDH) effort of standardization, specifically regarding fast controller characteristics. The prototypes will be built using two different form factors, PXIe and ATCA, with the aim of comparing the implementations. The presented solution took into consideration channel density, synchronization, resolution, sampling rates and the needs for signal conditioning such as filtering and galvanic isolation. The integration of the two controllers in the standard CODAC environment is also presented and discussed. Both controllers contain an EPICS IOC providing the interface to the mini-CODAC which will be used for all testing activities. The alpha version of the FPSC is also presented.

  14. Platform switching and bone platform switching.

    Science.gov (United States)

    Carinci, Francesco; Brunelli, Giorgio; Danza, Matteo

    2009-01-01

    Bone platform switching involves an inward bone ring in the coronal part of the implant that is in continuity with the alveolar bone crest. Bone platform switching is obtained by using a dental fixture with a reverse conical neck. A retrospective study was performed to evaluate the effectiveness of conventional vs reverse conical neck implants. In the period between May 2004 and November 2007, 86 patients (55 females and 31 males; median age, 53 years) were operated and 234 implants were inserted: 40 and 194 were conventional vs reverse conical neck implants, respectively. Kaplan-Meier algorithm and Cox regression were used to detect those variables associated with the clinical outcome. No differences in survival and success rates were detected between conventional vs reverse conical neck implants alone or in combination with any of the studied variables. Although bone platform switching leads to several advantages, no statistical difference in alveolar crest resorption is detected in comparison with reverse conical neck implants. We suppose that the proximity of the implant abutment junction to the alveolar crestal bone gives no protection against the microflora contained in the micrograph. Additional studies on larger series and a combination of platform switching and bone platform switching could lead to improved clinical outcomes.

  15. UA1 prototype detector

    CERN Document Server

    1980-01-01

    Prototype of UA1 central detector inside a plexi tube. The UA1 experiment ran at CERN's Super Proton Synchrotron and made the Nobel Prize winning discovery of W and Z particles in 1983. The UA1 central detector was crucial to understanding the complex topology of proton-antiproton events. It played a most important role in identifying a handful of Ws and Zs among billions of collisions. The detector was essentially a wire chamber - a 6-chamber cylindrical assembly 5.8 m long and 2.3 m in diameter, the largest imaging drift chamber of its day. It recorded the tracks of charged particles curving in a 0.7 Tesla magnetic field, measuring their momentum, the sign of their electric charge and their rate of energy loss (dE/dx). Atoms in the argon-ethane gas mixture filling the chambers were ionised by the passage of charged particles. The electrons which were released drifted along an electric field shaped by field wires and were collected on sense wires. The geometrical arrangement of the 17000 field wires and 6...

  16. Space Warfighting Construct: Prototyping

    Science.gov (United States)

    Teehan, R. F.; Anttonen, J. S.; Stein, J. M.; Stearns, J. A.

    Space is undergoing a period of great change, as the barriers to entry are lowering in every arena. Launch to any orbit is becoming more routine and feasible thanks to industry innovation, the rise of small- and cubesats, and the use of ESPA rings enabling “freight trains to GEO.” With more regular rides to space, there is a concomitant rise in the capability for space qualification, technology validation and verification, and all types of experimentation in both the space and ground segments. The types of architectures that commercial and government agencies develop is being influenced because space is becoming more accessible. Whereas current architectures are designed to have four to six satellites perform a mission, in the future that same mission may be distributed among dozens, hundreds, or even thousands of satellites. This changing landscape is something of a double-edged sword for Space Situational Awareness (SSA): safety of flight becomes a heightened concern, but the opportunities for the entire community to innovate, prototype, and ultimately provide novel, robust solutions have never been greater.

  17. Prototyping Design and Business

    DEFF Research Database (Denmark)

    Rasmussen, Jørgen; Kramp, Gunnar; Schiønning Mortensen, Bo

    2011-01-01

    It is increasingly common that design firms go from working with their client’s development department on specific products, to discussing strategic issues directly with the company’s management. In this new territory designers face a number of challenges. Designers are traditionally trained to ‘...... for collaboration and interdisciplinary development. Based on the thinking behind a prototype presentation the paper describes a specific case where the model is used in collaboration between a team of designers and the management of a medium-sized company........ This paper suggests a model, ‘The Strategic Design Matrix,’ to bridge the gap between the design approach and the management approach to strategic development processes. Through common references, a common language and a common basis understanding, the model aims to create a communicative platform......It is increasingly common that design firms go from working with their client’s development department on specific products, to discussing strategic issues directly with the company’s management. In this new territory designers face a number of challenges. Designers are traditionally trained...

  18. Experimental demonstration of OSPF-TE extensions in muiti-domain OBS networks connected by GMPLS network

    Science.gov (United States)

    Tian, Chunlei; Yin, Yawei; Wu, Jian; Lin, Jintong

    2008-11-01

    The interworking network of Generalized Multi-Protocol Label Switching (GMPLS) and Optical Burst Switching (OBS) is attractive network architecture for the future IP/DWDM network nowadays. In this paper, OSPF-TE extensions for multi-domain Optical Burst Switching networks connected by GMPLS controlled WDM network are proposed, the corresponding experimental results such as the advertising latency are also presented by using an OBS network testbed. The experimental results show that it works effectively on the OBS/GMPLS networks.

  19. Enhancement of an optical burst switch with shared electronic buffers

    OpenAIRE

    Delesques, Pierre; Bonald, Thomas; Froc, Gwillerm; Ciblat, Philippe; Ware, Cédric

    2013-01-01

    International audience; Future data networks face an energy consumption challenge: traffic grows exponentially, but the energy cost per bit in electronic routers and switches does not decrease so fast. All-optical switching techniques have not delivered a solution to this problem: despite their requiring fewer energetically-costly optical-to-electronic conversions, they suffer from poor contention handling even at low network loads, thus needing heavy overprovisioning, which negates the energ...

  20. Bufferless transmission in complex networks

    OpenAIRE

    Pu, Cunlai; Cui, Wei; Wu, Jiexin; Yang, Jian

    2017-01-01

    Complex bufferless networks such as on-chip networks and optical burst switching networks haven't been paid enough attention in network science. In complex bufferless networks, the store and forward mechanism is not applicable, since the network nodes are not allowed to buffer data packets. In this paper, we study the data transmission process in complex bufferless networks from the perspective of network science. Specifically, we use the Price model to generate the underlying network topolog...

  1. Expert system in power distribution lines switching; Sistema especialista em manobras de redes de distribuicao de energia eletrica

    Energy Technology Data Exchange (ETDEWEB)

    Cavellucci, Celso

    1989-07-01

    This work proposes an expert system integrated to procedures of numerical computation, denominated RD and projected to suggest alternatives of switching plans in the isolation and re-establishment of power distribution lines. The switching plans are based on the specialist's knowledge (network operator) and in evaluations of the electric conditions of the switching. Specialist's knowledge is represented in the form of triples (context, attribute, value) and production rules, that are evaluated conveniently by the machine of inference of the RD system. The electric power distribution is represented by a graph model, where the knots are load blocks and the arcs are key of the system. The evaluation of the electric requirements (voltage drop and physical capacity of the components of the power distribution lines) it is obtained through a maneuver simulator (numeric computation). The maneuver simulator bases on the Method of the Moments for the calculation of the voltage drop. With base in these ideas a prototype of the RD system was developed.

  2. Denoising of genetic switches based on Parrondo's paradox

    Science.gov (United States)

    Fotoohinasab, Atiyeh; Fatemizadeh, Emad; Pezeshk, Hamid; Sadeghi, Mehdi

    2018-03-01

    Random decision making in genetic switches can be modeled as tossing a biased coin. In other word, each genetic switch can be considered as a game in which the reactive elements compete with each other to increase their molecular concentrations. The existence of a very small number of reactive element molecules has caused the neglect of effects of noise to be inevitable. Noise can lead to undesirable cell fate in cellular differentiation processes. In this paper, we study the robustness to noise in genetic switches by considering another switch to have a new gene regulatory network (GRN) in which both switches have been affected by the same noise and for this purpose, we will use Parrondo's paradox. We introduce two networks of games based on possible regulatory relations between genes. Our results show that the robustness to noise can increase by combining these noisy switches. We also describe how one of the switches in network II can model lysis/lysogeny decision making of bacteriophage lambda in Escherichia coli and we change its fate by another switch.

  3. Context-sensitive service discovery experimental prototype and evaluation

    DEFF Research Database (Denmark)

    Balken, Robin; Haukrogh, Jesper; L. Jensen, Jens

    2007-01-01

    The amount of different networks and services available to users today are increasing. This introduces the need for a way to locate and sort out irrelevant services in the process of discovering available services to a user. This paper describes and evaluates a prototype of an automated discovery...... to increase network scalability. The experimental analysis of service discovery times for different scenarios is used to optimize parameter settings of the service discovery system in order to achieve short response times....

  4. The SONG prototype: Efficiency of a robotic telescope

    DEFF Research Database (Denmark)

    Andersen, M. F.; Grundahl, F.; Beck, A. H.

    2016-01-01

    The Stellar Observations Network Group prototype telescope at the Teide Observatory has been operating in scientific mode since March 2014. The first year of observations has entirely been carried out using the high resolution echelle spectrograph. Several asteroseismic targets were selected for ...

  5. High energy semiconductor switch

    Science.gov (United States)

    Risberg, R. L.

    1989-02-01

    The objective was a controller for electric motors. By operating standard Nema B induction motors at variable speed a great deal of energy is saved. This is especially true in pumping and air conditioning applications. To allow wider use of variable speed AC drives, and to provide improved performance, a better semiconductor switch was sought. This was termed the High Energy Semiconductor Switch.

  6. Switched reluctance motor drives

    Indian Academy of Sciences (India)

    Davis RM, Ray WF, Blake RJ 1981 Inverter drive for switched reluctance: circuits and component ratings. Inst. Elec. Eng. Proc. B128: 126-136. Ehsani M. 1991 Position Sensor elimination technique for the switched reluctance motor drive. US Patent No. 5,072,166. Ehsani M, Ramani K R 1993 Direct control strategies based ...

  7. Quantum cryptography without switching.

    Science.gov (United States)

    Weedbrook, Christian; Lance, Andrew M; Bowen, Warwick P; Symul, Thomas; Ralph, Timothy C; Lam, Ping Koy

    2004-10-22

    We propose a new coherent state quantum key distribution protocol that eliminates the need to randomly switch between measurement bases. This protocol provides significantly higher secret key rates with increased bandwidths than previous schemes that only make single quadrature measurements. It also offers the further advantage of simplicity compared to all previous protocols which, to date, have relied on switching.

  8. Switch on, switch off: stiction in nanoelectromechanical switches

    KAUST Repository

    Wagner, Till J W

    2013-06-13

    We present a theoretical investigation of stiction in nanoscale electromechanical contact switches. We develop a mathematical model to describe the deflection of a cantilever beam in response to both electrostatic and van der Waals forces. Particular focus is given to the question of whether adhesive van der Waals forces cause the cantilever to remain in the \\'ON\\' state even when the electrostatic forces are removed. In contrast to previous studies, our theory accounts for deflections with large slopes (i.e. geometrically nonlinear). We solve the resulting equations numerically to study how a cantilever beam adheres to a rigid electrode: transitions between \\'free\\', \\'pinned\\' and \\'clamped\\' states are shown to be discontinuous and to exhibit significant hysteresis. Our findings are compared to previous results from linearized models and the implications for nanoelectromechanical cantilever switch design are discussed. © 2013 IOP Publishing Ltd.

  9. The Software Engineering Prototype.

    Science.gov (United States)

    1983-06-01

    sequential problem solving in which the cycles form networks. An essential part of this model is the continuous feedback between tke designer and the...34Systems, Reitv and the SystEms Pracgioner", Journal of Systems Man_ emen&, January 1981, p. 26-28. --.... Jnuar 34. Gilt , Tom "High-Level Systems...Development", Software Sngineri.& Note.s, vol. 6, no. 2, April 1981, T.- 7" 45. Stavely, Allan I. ,"Design Feedback and ims Use in Software resign

  10. Micro/macro prototyping

    OpenAIRE

    Nold, Christian

    2015-01-01

    While urban computing has often been envisaged as bridging place, technology and people, there is a gap between the micro-level of urban computing which focuses on the solitary user with technological solutions and the macro-level which proposes grand visions of making better cities for the public. The gap is one of scale of audience as well as scale of normative ambition. To bridge this gap the paper proposes a transdisciplinary approach that brings together actor–network theory with critica...

  11. Learning Axure RP interactive prototypes

    CERN Document Server

    Krahenbuhl, John Henry

    2015-01-01

    If you are a user experience professional, designer, information architect, or business analyst who wants to gain interactive prototyping skills with Axure, then this book is ideal for you. Some familiarity with Axure is preferred but not essential.

  12. Optical Networks for Cost Monitoring and Reduction

    OpenAIRE

    R Buvanesvari; V Amala Saint Thomas; M Rajeswari; A Rajaram Kumar

    2011-01-01

    This paper focuses on cost reduction and monitoring in optical networks. Optical mesh networks are cost savings with switching systems that are interconnected by point-to-point networks. Transponders play a major role in it. All-optical packet switching has been intensively investigated in recent years as an alternative to static, cross connect based networks. Several switch architectures have been proposed, all of them using buffers made of fiber delay lines. We consider the problem of minim...

  13. Exploring adolescent cognitive control in a combined interference switching task.

    Science.gov (United States)

    Mennigen, Eva; Rodehacke, Sarah; Müller, Kathrin U; Ripke, Stephan; Goschke, Thomas; Smolka, Michael N

    2014-08-01

    Cognitive control enables individuals to flexibly adapt to environmental challenges. In the present functional magnetic resonance imaging (fMRI) study, we investigated 185 adolescents at the age of 14 with a combined response interference switching task measuring behavioral responses (reaction time, RT and error rate, ER) and brain activity during the task. This task comprises two types of conflict which are co-occurring, namely, task switching and stimulus-response incongruence. Data indicated that already in adolescents an overlapping cognitive control network comprising the dorsal anterior cingulate cortex (dACC), dorsolateral prefrontal cortex (DLPFC), pre-supplementary motor area (preSMA) and posterior parietal cortex (PPC) is recruited by conflicts arising from task switching and response incongruence. Furthermore our study revealed higher blood oxygenation level dependent (BOLD) responses elicited by incongruent stimuli in participants with a pronounced incongruence effect, calculated as the RT difference between incongruent and congruent trials. No such correlation was observed for switch costs. Furthermore, increased activation of the default mode network (DMN) was only observed in congruent trials compared to incongruent trials, but not in task repetition relative to task switch trials. These findings suggest that even though the two processes of task switching and response incongruence share a common cognitive control network they might be processed differentially within the cognitive control network. Results are discussed in the context of a novel hypothesis concerning antagonistic relations between the DMN and the cognitive control network. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Comparative Developmental Transcriptomics Reveals Rewiring of a Highly Conserved Gene Regulatory Network during a Major Life History Switch in the Sea Urchin Genus Heliocidaris.

    Directory of Open Access Journals (Sweden)

    Jennifer W Israel

    2016-03-01

    Full Text Available The ecologically significant shift in developmental strategy from planktotrophic (feeding to lecithotrophic (nonfeeding development in the sea urchin genus Heliocidaris is one of the most comprehensively studied life history transitions in any animal. Although the evolution of lecithotrophy involved substantial changes to larval development and morphology, it is not known to what extent changes in gene expression underlie the developmental differences between species, nor do we understand how these changes evolved within the context of the well-defined gene regulatory network (GRN underlying sea urchin development. To address these questions, we used RNA-seq to measure expression dynamics across development in three species: the lecithotroph Heliocidaris erythrogramma, the closely related planktotroph H. tuberculata, and an outgroup planktotroph Lytechinus variegatus. Using well-established statistical methods, we developed a novel framework for identifying, quantifying, and polarizing evolutionary changes in gene expression profiles across the transcriptome and within the GRN. We found that major changes in gene expression profiles were more numerous during the evolution of lecithotrophy than during the persistence of planktotrophy, and that genes with derived expression profiles in the lecithotroph displayed specific characteristics as a group that are consistent with the dramatically altered developmental program in this species. Compared to the transcriptome, changes in gene expression profiles within the GRN were even more pronounced in the lecithotroph. We found evidence for conservation and likely divergence of particular GRN regulatory interactions in the lecithotroph, as well as significant changes in the expression of genes with known roles in larval skeletogenesis. We further use coexpression analysis to identify genes of unknown function that may contribute to both conserved and derived developmental traits between species

  15. Comparative Developmental Transcriptomics Reveals Rewiring of a Highly Conserved Gene Regulatory Network during a Major Life History Switch in the Sea Urchin Genus Heliocidaris.

    Science.gov (United States)

    Israel, Jennifer W; Martik, Megan L; Byrne, Maria; Raff, Elizabeth C; Raff, Rudolf A; McClay, David R; Wray, Gregory A

    2016-03-01

    The ecologically significant shift in developmental strategy from planktotrophic (feeding) to lecithotrophic (nonfeeding) development in the sea urchin genus Heliocidaris is one of the most comprehensively studied life history transitions in any animal. Although the evolution of lecithotrophy involved substantial changes to larval development and morphology, it is not known to what extent changes in gene expression underlie the developmental differences between species, nor do we understand how these changes evolved within the context of the well-defined gene regulatory network (GRN) underlying sea urchin development. To address these questions, we used RNA-seq to measure expression dynamics across development in three species: the lecithotroph Heliocidaris erythrogramma, the closely related planktotroph H. tuberculata, and an outgroup planktotroph Lytechinus variegatus. Using well-established statistical methods, we developed a novel framework for identifying, quantifying, and polarizing evolutionary changes in gene expression profiles across the transcriptome and within the GRN. We found that major changes in gene expression profiles were more numerous during the evolution of lecithotrophy than during the persistence of planktotrophy, and that genes with derived expression profiles in the lecithotroph displayed specific characteristics as a group that are consistent with the dramatically altered developmental program in this species. Compared to the transcriptome, changes in gene expression profiles within the GRN were even more pronounced in the lecithotroph. We found evidence for conservation and likely divergence of particular GRN regulatory interactions in the lecithotroph, as well as significant changes in the expression of genes with known roles in larval skeletogenesis. We further use coexpression analysis to identify genes of unknown function that may contribute to both conserved and derived developmental traits between species. Collectively, our results

  16. Electroretinography in dogs using a fiber electrode prototype

    Directory of Open Access Journals (Sweden)

    A.L. Pereira

    Full Text Available We compared two electroretinography (ERG electrodes in dogs using ERG standards of the International Society for Clinical Electrophysiology of Vision (ISCEV. Ten healthy Yorkshire terrier dogs (mean age, 2.80 ± 1.42 years; 6 females weighing 5.20 ± 1.56 kg were evaluated using an ERG system for veterinary use. Dark- and light-adapted ERG responses were recorded using an ERG-Jet electrode and a fiber electrode prototype. The examinations were performed during 2 visits, 3 weeks apart. Both electrodes (ERG-Jet or fiber prototype were used on each animal and the first eye to be recorded (OD × OS was selected randomly. Three weeks later the examination was repeated on the same animal switching the type of electrode to be used that day and the first eye to be examined. The magnitude and waveform quality obtained with the two electrode types were similar for all ERG responses. ERG amplitudes and implicit times obtained from dogs using the fiber electrode prototype were comparable to those obtained with the ERG-Jet electrode for rod, maximal rod-cone summed, cone, and 30-Hz flicker responses. The fiber electrode prototype is a low-cost device, available as an alternative instrument for clinical veterinary ERG recording for retinal function assessment.

  17. Electroretinography in dogs using a fiber electrode prototype

    Directory of Open Access Journals (Sweden)

    A.L. Pereira

    2013-03-01

    Full Text Available We compared two electroretinography (ERG electrodes in dogs using ERG standards of the International Society for Clinical Electrophysiology of Vision (ISCEV. Ten healthy Yorkshire terrier dogs (mean age, 2.80 ± 1.42 years; 6 females weighing 5.20 ± 1.56 kg were evaluated using an ERG system for veterinary use. Dark- and light-adapted ERG responses were recorded using an ERG-Jet electrode and a fiber electrode prototype. The examinations were performed during 2 visits, 3 weeks apart. Both electrodes (ERG-Jet or fiber prototype were used on each animal and the first eye to be recorded (OD × OS was selected randomly. Three weeks later the examination was repeated on the same animal switching the type of electrode to be used that day and the first eye to be examined. The magnitude and waveform quality obtained with the two electrode types were similar for all ERG responses. ERG amplitudes and implicit times obtained from dogs using the fiber electrode prototype were comparable to those obtained with the ERG-Jet electrode for rod, maximal rod-cone summed, cone, and 30-Hz flicker responses. The fiber electrode prototype is a low-cost device, available as an alternative instrument for clinical veterinary ERG recording for retinal function assessment.

  18. Aspects Regarding SF6 Switch Disconnector Framework Design

    Directory of Open Access Journals (Sweden)

    Liviu NEAMT

    2016-12-01

    Full Text Available The complexity of the designing process of a switch disconnector framework comes from the almost impossible task to appreciate the discrepancy between the ideal and practical electric strength. Complicated geometries characterized by nonuniform fields are predesigned based on a set of analytical relations and corrected/optimized based on numerical methods and high voltage testing on prototypes. This paper suggest some approaches to minimize the effort and the steps required to achieve an acceptable stainless steel housing, in the insulators area, for a medium voltage SF6 switch disconnector. The results are based on simple analytical evaluation and finite element analysis in both 2D and 3D configurations.

  19. A Metabolic Switch

    DEFF Research Database (Denmark)

    Hjorth, Poul G.

    Our muscles are metabolically flexible, i.e., they are capable of `switching' between two types of oxidation: (1) when fasting, a predominantly lipid oxidation with high rates of fatty acid uptake, and (2) when fed, suppression of lipid oxidation in favour of increased glucose uptake, oxidation...... and storage, in response to insulin. One of the many manifestations of obesity and Type 2 diabetes is an insulin resistance of the skeletal muscles, which suppresses this metabolic switch. This talk describes recent development of a low-dimensional system of ODEs that model the metabolic switch, displaying...

  20. Photoconductive switch package

    Science.gov (United States)

    Ca[rasp, George J

    2013-10-22

    A photoconductive switch is formed of a substrate that has a central portion of SiC or other photoconductive material and an outer portion of cvd-diamond or other suitable material surrounding the central portion. Conducting electrodes are formed on opposed sides of the substrate, with the electrodes extending beyond the central portion and the edges of the electrodes lying over the outer portion. Thus any high electric fields produced at the edges of the electrodes lie outside of and do not affect the central portion, which is the active switching element. Light is transmitted through the outer portion to the central portion to actuate the switch.

  1. Network security

    CERN Document Server

    Perez, André

    2014-01-01

    This book introduces the security mechanisms deployed in Ethernet, Wireless-Fidelity (Wi-Fi), Internet Protocol (IP) and MultiProtocol Label Switching (MPLS) networks. These mechanisms are grouped throughout the book according to the following four functions: data protection, access control, network isolation, and data monitoring. Data protection is supplied by data confidentiality and integrity control services. Access control is provided by a third-party authentication service. Network isolation is supplied by the Virtual Private Network (VPN) service. Data monitoring consists of applying

  2. New Photonic System for Optical Packet Switching

    Directory of Open Access Journals (Sweden)

    F. Rudge Barbosa

    2003-08-01

    Full Text Available Fast optical switching (ms timebase is realized by using a RF frequency tone inserted in the optical packet that carries a digital payload. By using a highly selective RF filtering for optical packet header frequency recognition, we have obtained excellent performance in optical switching function.. The RF header is detected at optical node input, and signals the node switching control, which instantly directs the packet to a prescribed output. No electronic processing of the digital payload is performed. The optical circuit is noise-free, has very low crosstalk, and is extremely selective in header frequency detection. BER measurements for payload consistently yield figures as low as 10-12 . This system is applicable to optical metropolitan and access networks, and is fully compatible with DWDM systems.

  3. Stochastic dynamics of macromolecular-assembly networks.

    Science.gov (United States)

    Saiz, Leonor; Vilar, Jose

    2006-03-01

    The formation and regulation of macromolecular complexes provides the backbone of most cellular processes, including gene regulation and signal transduction. The inherent complexity of assembling macromolecular structures makes current computational methods strongly limited for understanding how the physical interactions between cellular components give rise to systemic properties of cells. Here we present a stochastic approach to study the dynamics of networks formed by macromolecular complexes in terms of the molecular interactions of their components [1]. Exploiting key thermodynamic concepts, this approach makes it possible to both estimate reaction rates and incorporate the resulting assembly dynamics into the stochastic kinetics of cellular networks. As prototype systems, we consider the lac operon and phage λ induction switches, which rely on the formation of DNA loops by proteins [2] and on the integration of these protein-DNA complexes into intracellular networks. This cross-scale approach offers an effective starting point to move forward from network diagrams, such as those of protein-protein and DNA-protein interaction networks, to the actual dynamics of cellular processes. [1] L. Saiz and J.M.G. Vilar, submitted (2005). [2] J.M.G. Vilar and L. Saiz, Current Opinion in Genetics & Development, 15, 136-144 (2005).

  4. A similarity-based community detection method with multiple prototype representation

    OpenAIRE

    Zhou, Kuang; Martin, Arnaud; Pan, Quan

    2015-01-01

    International audience; Communities are of great importance for understanding graph structures in social networks. Some existing community detection algorithms use a single prototype to represent each group. In real applications, this may not adequately model the different types of communities and hence limits the clustering performance on social networks. To address this problem, a Similarity-based Multi-Prototype (SMP) community detection approach is proposed in this paper. In SMP, vertices...

  5. Sleep State Switching

    National Research Council Canada - National Science Library

    Saper, Clifford B; Fuller, Patrick M; Pedersen, Nigel P; Lu, Jun; Scammell, Thomas E

    2010-01-01

    We take for granted the ability to fall asleep or to snap out of sleep into wakefulness, but these changes in behavioral state require specific switching mechanisms in the brain that allow well-defined state transitions...

  6. Photonics in switching

    CERN Document Server

    Midwinter, John E; Kelley, Paul

    1993-01-01

    Photonics in Switching provides a broad, balanced overview of the use of optics or photonics in switching, from materials and devices to system architecture. The chapters, each written by an expert in the field, survey the key technologies, setting them in context and highlighting their benefits and possible applications. This book is a valuable resource for those working in the communications industry, either at the professional or student level, who do not have extensive background knowledge or the underlying physics of the technology.

  7. uv preilluminated gas switches

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, L.P.; Orham, E.L.; Stowers, I.F.; Braucht, J.R.

    1980-06-03

    We have designed, built, and characterized uv preilluminated gas switches for a trigger circuit and a low inductance discharge circuit. These switches have been incorporated into a 54 x 76 x 150 cm pulser module to produce a 1 Ma output current rising at 5 x 10/sup 12/ amps/sec with 1 ns jitter. Twenty such modules will be used on the Nova Inertial Confinement Fusion Laser System for plasma retropulse shutters.

  8. Computer-communication networks

    CERN Document Server

    Meditch, James S

    1983-01-01

    Computer- Communication Networks presents a collection of articles the focus of which is on the field of modeling, analysis, design, and performance optimization. It discusses the problem of modeling the performance of local area networks under file transfer. It addresses the design of multi-hop, mobile-user radio networks. Some of the topics covered in the book are the distributed packet switching queuing network design, some investigations on communication switching techniques in computer networks and the minimum hop flow assignment and routing subject to an average message delay constraint

  9. Electronic implementation of optical burst switching techniques

    Science.gov (United States)

    Albanese, Ilijc; Darcie, Thomas E.; Ganti, Sudhakar

    2013-10-01

    Extensive research effort is ongoing in energy-efficient Internet-based communications. Optical Flow Switching (OFS) and Optical Burst Switching (OBS) offer potentially efficient alternatives to IP-router-based networks for large data transactions, but significant challenges remain. OFS requires each user to install expensive core network technology, limiting application to highly specialized nodes. OBS can achieve higher scalability but burst assembly/disassembly procedures reduce power efficiency. Finally both OFS and OBS use all-optical switching technologies for which energy efficiency and flexibility remain subject to debate. Our study aims at combining the advantages of both OBS and OFS while avoiding their shortcomings. We consider using a two-way resource reservation protocol for periodic concatenations of large (e.g. 1 Mb) packets or Media Frames (MFs). These chains of MFs (MFCs) are semi-transparent with a periodicity referred to as the "transparency degree". Each MFC is assembled and stored at an end-user machine during the resource reservation procedure and is then switched and buffered electronically along its path. The periodic configuration of each MFC enables interleaving of several chains using buffering only to align the MFs in each MFC in time, largely reducing the buffer requirements with respect to OBS. This periodicity also enables a simple scheduling algorithm to schedule large transactions with minimal control plane processing, achieving link utilization approaching 99.9%. In summary, results indicate that implementing optical burst switching techniques in the electronic domain is a compelling path forward to high-throughput power-efficient networking.

  10. Supporting Active User Involvment in Prototyping

    DEFF Research Database (Denmark)

    Grønbæk, Kaj

    1990-01-01

    development of prototypes to early evaluation of prototypes in envisioned use situations. Having users involved in such activities creates new requirements for tool support. Tools that support direct manipulation of prototypes and simulation of behaviour have shown promise for cooperative prototyping...

  11. Real-time earthquake alert system for the greater San Francisco Bay Area: a prototype design to address operational issues

    Energy Technology Data Exchange (ETDEWEB)

    Harben, P.E.; Jarpe, S.; Hunter, S.

    1996-12-10

    The purpose of the earthquake alert system (EAS) is to outrun the seismic energy released in a large earthquake using a geographically distributed network of strong motion sensors that telemeter data to a rapid CPU-processing station, which then issues an area-wide warning to a region before strong motion will occur. The warning times involved are short, from 0 to 30 seconds or so; consequently, most responses must be automated. The San Francisco Bay Area is particularly well suited for an EAS because (1) large earthquakes have relatively shallow hypocenters (10- to 20-kilometer depth), giving favorable ray-path geometries for larger warning times than deeper from earthquakes, and (2) the active faults are few in number and well characterized, which means far fewer geographically distributed strong motion sensors are (about 50 in this region). An EAS prototype is being implemented in the San Francisco Bay Area. The system consists of four distinct subsystems: (1) a distributed strong motion seismic network, (2) a central processing station, (3) a warning communications system and (4) user receiver and response systems. We have designed a simple, reliable, and inexpensive strong motion monitoring station that consists of a three-component Analog Devices ADXLO5 accelerometer sensing unit, a vertical component weak motion sensor for system testing, a 16-bit digitizer with multiplexing, and communication output ports for RS232 modem or radio telemetry. The unit is battery-powered and will be sited in fire stations. The prototype central computer analysis system consists of a PC dam-acquisition platform that pipes the incoming strong motion data via Ethernet to Unix-based workstations for dam processing. Simple real-time algorithms, particularly for magnitude estimation, are implemented to give estimates of the time since the earthquake`s onset its hypocenter location, its magnitude, and the reliability of the estimate. These parameters are calculated and transmitted

  12. A simple livelock-free algorithm for packet switching

    National Research Council Canada - National Science Library

    Shyamasundar, R.K

    1984-01-01

    ... as a livelock-free algorithm for packet switching is obtained using the strategy of the banker's algorithm. Furthermore, the solution obtained is interpreted for the hyper-fast banker's problem. 1. Introduction In most cases, the occurrence of network deadlock has a horrendous impact upon network users. When the deadlocks are discovered, they are frequ...

  13. Implementation of remote monitoring and managing switches

    Science.gov (United States)

    Leng, Junmin; Fu, Guo

    2010-12-01

    In order to strengthen the safety performance of the network and provide the big convenience and efficiency for the operator and the manager, the system of remote monitoring and managing switches has been designed and achieved using the advanced network technology and present network resources. The fast speed Internet Protocol Cameras (FS IP Camera) is selected, which has 32-bit RSIC embedded processor and can support a number of protocols. An Optimal image compress algorithm Motion-JPEG is adopted so that high resolution images can be transmitted by narrow network bandwidth. The architecture of the whole monitoring and managing system is designed and implemented according to the current infrastructure of the network and switches. The control and administrative software is projected. The dynamical webpage Java Server Pages (JSP) development platform is utilized in the system. SQL (Structured Query Language) Server database is applied to save and access images information, network messages and users' data. The reliability and security of the system is further strengthened by the access control. The software in the system is made to be cross-platform so that multiple operating systems (UNIX, Linux and Windows operating systems) are supported. The application of the system can greatly reduce manpower cost, and can quickly find and solve problems.

  14. Aging Investigation of CMS EMU Prototype Chambers

    CERN Document Server

    Ferguson*, T; Krivshich, Anatoli; Kuznetsova, Ekaterina; Lobachev, Evgeny; Mitselmakher, Guenakh; Schipunov, L

    1999-01-01

    The aging investigation results of CMS EMU prototype chambers are presented. Aging tests under sustained irradiation by a 90Sr 2 Ci were performed with three working gas mixtures Ar( 30%)+CO2( 50%)+CF4( 20%), Ar( 30%)+CO2( 70%) and Ar( 40%)+CO2( 50%)+CF4( 10%). For Ar( 30%)+CO2( 50%)+CF4( 20%) mixture gas gain reduction was not observed up to the accumulated charge Q = 13.56 C/cm. However, the dark current in the chamber was noticeable starting already from Q = 2 C/cm. The absence of the CF4 ( in the Ar/CO2 gas mixture) caused fast aging deterioration, and Q = 0.2 C/cm was enough to obtain 50% of the gas gain reduction. In the test with Ar( 40%)+CO2( 50%)+CF4( 10%) mixture the gas gain reduction and the dark current increase were not observed up to Q = 13.35 C/cm. Reduction of the gas flow rate to 0.1 volume per day caused 50% of the gain decrease due to the gas pollution by fragments of dissociated gas molecules. The gain restored after switching back to the 1 volume per day flow rate. Studies with electroni...

  15. Digital Prototyping of Milk Products

    DEFF Research Database (Denmark)

    Frisvad, Jeppe Revall; Nielsen, Otto Højager Attermann; Skytte, Jacob Lercke

    2012-01-01

    an acidification process over time. The challenge is to investigate whether we can use the resulting diffuse reflectance images to measure the static structure factor or similar optical properties of gels. We can see some correlation between measured diffuse reflectance and the rheology of the gel. This indicates...... the extension. This work was (in part) financed by the Centre for Imaging Food Quality project which is funded by the Danish Council for Strategic Research (contract no 09-067039) within the Programme Commission on Health, Food and Welfare. This work was also in part financed by the Digital Prototypes project......Digital prototyping has revolutionised the automotive industry by providing designers and engineers with digital models of their products that enable virtual product design, visualisation, and simulation [1]. However, digital prototyping does not exist in the food industry as the colloidal nature...

  16. Low inductance gas switching.

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, Ray; Harjes, Henry Charles III; Wallace, Zachariah; Elizondo, Juan E.

    2007-10-01

    The laser trigger switch (LTS) is a key component in ZR-type pulsed power systems. In ZR, the pulse rise time through the LTS is > 200 ns and additional stages of pulse compression are required to achieve the desired <100 ns rise time. The inductance of the LTS ({approx}500nH) in large part determines the energy transfer time through the switch and there is much to be gained in improving system performance and reducing system costs by reducing this inductance. The current path through the cascade section of the ZR LTS is at a diameter of {approx} 6-inches which is certainly not optimal from an inductance point of view. The LTS connects components of much greater diameter (typically 4-5 feet). In this LDRD the viability of switch concepts in which the diameter of cascade section is greatly increased have been investigated. The key technical question to be answered was, will the desired multi-channel behavior be maintained in a cascade section of larger diameter. This LDRD proceeded in 2 distinct phases. The original plan for the LDRD was to develop a promising switch concept and then design, build, and test a moderate scale switch which would demonstrate the key features of the concept. In phase I, a switch concept which meet all electrical design criteria and had a calculated inductance of 150 nH was developed. A 1.5 MV test switch was designed and fabrication was initiated. The LDRD was then redirected due to budgetary concerns. The fabrication of the switch was halted and the focus of the LDRD was shifted to small scale experiments designed to answer the key technical question concerning multi-channel behavior. In phase II, the Multi-channel switch test bed (MCST) was designed and constructed. The purpose of MCST was to provide a versatile, fast turn around facility for the study the multi-channel electrical breakdown behavior of a ZR type cascade switch gap in a parameter space near that of a ZR LTS. Parameter scans on source impedance, gap tilt, gap spacing and

  17. RANCANGAN PROTOTYPE ALAT PEMANTAU JUMLAH PENGUNJUNG MINIMARKET BERBASIS SMS GATEWAY

    Directory of Open Access Journals (Sweden)

    Suleman Suleman

    2016-03-01

    Full Text Available Abstract - Has designed and implemented the monitoring system, the number of visitors to the minimart based sms gateway using microcontroller ATMega8. If the first minimarket (glass was opened, then automatically limit switch 1 on the first door is depressed, so that would indicate to the microcontroller to give orders to the wavecom modem convert to the owner. The second condition, namely if the minimarket is closed then automatically limit switch 2 is depressed, it will then indicate to the microcontroller to give orders to the wavecom modem for sending sms to the owner. The design of this system using the method of architecture that consists of several stages, namely, (1 analysis of needs, (2, (3 design, Implementation arrangements, Testing tools (4, (5 test procedure and (6 Making Tools. The hardware consists of a limit switch, infrared, ATMega8 microcontroller as a minimum system controller circuit controller inputs and outputs, the output display circuit using IC MAX 232 wavecom modem that is linked to. The software is written with BASCOM-AVR Keyword : Design Of Prototype Tools Monitor The Number Of Visitors To The Minimarket, SMS Gateway Abstrak - Telah dirancang dan implementasikan sistem pemantau jumlah pengunjung minimarket berbasis sms gateway menggunakan mikrokontroler ATMega8. Jika pintu minimarket pertama (kaca dibuka, maka secara otomatis limit switch 1 yang terdapat pada pintu pertama tertekan, sehingga akan mengindikasikan kepada mikrokontroler untuk memberikan perintah kepada modem wavecom untuk menggirimkan sms kepada owner. Keadaan kedua yaitu jika pintu minimarket ditutup maka secara otomatis limit switch 2 tertekan, kemudian akan mengindikasikan kepada mikrokontroler untuk memberikan perintah kepada modem wavecom untuk mengirimkan sms kepada owner. Perancangan sistem ini menggunakan metode rancang bangun yang terdiri beberapa tahap yaitu, (1 Analisis kebutuhan, (2 Perancangan, (3 Implementasi rangkaian, (4 Pengujian alat

  18. Noise-driven attractor switching device

    Science.gov (United States)

    Asakawa, Naoki; Hotta, Yasushi; Kanki, Teruo; Kawai, Tomoji; Tabata, Hitoshi

    2009-02-01

    Problems with artificial neural networks originate from their deterministic nature and inevitable prior learnings, resulting in inadequate adaptability against unpredictable, abrupt environmental change. Here we show that a stochastically excitable threshold unit can be utilized by these systems to partially overcome the environmental change. Using an excitable threshold system, attractors were created that represent quasiequilibrium states into which a system settles until disrupted by environmental change. Furthermore, noise-driven attractor stabilization and switching were embodied by inhibitory connections. Noise works as a power source to stabilize and switch attractors, and endows the system with hysteresis behavior that resembles that of stereopsis and binocular rivalry in the human visual cortex. A canonical model of the ring network with inhibitory connections composed of class 1 neurons also shows properties that are similar to the simple threshold system.

  19. Composites by rapid prototyping technology

    CSIR Research Space (South Africa)

    Kumar, S

    2010-02-01

    Full Text Available powder is a fiber, problems of manufacturing occur. The method has also been used to make Metal Matrix Composite (MMC), e.g Fe and graphite [17], WC-Co [18,19], WC-Co and Cu [20,21], Fe, Ni and TiC [22] etc and Ceramic Matrix Composite (CMC) e.g. Si... of various materials used. Key words: : Rapid Prototyping (RP), Laser, Composites 1 Introduction Rapid Prototyping (RP) initially focussed on polymers. These were later re- placed/supplemented by ceramics, metals and composites. Composites are used in RP...

  20. Axure RP 6 Prototyping Essentials

    CERN Document Server

    Schwartz, Ezra

    2012-01-01

    Axure RP 6 Prototyping Essentials is a detailed, practical primer on the leading rapid prototyping tool. Short on jargon and high on concepts, real-life scenarios and step-by-step guidance through hands-on examples, this book will show you how to integrate Axure into your UX workflow. This book is written for UX practitioners, business analysts, product managers, and anyone else who is involved in UX projects. The book assumes that you have no or very little familiarity with Axure. It will help you if you are evaluating the tool for an upcoming project or are required to quickly get up to spee

  1. Design and realization of a tactile switches module with capacitive sensing method implemented with a microcontroller

    Directory of Open Access Journals (Sweden)

    Lorenzo Capineri

    2016-08-01

    Full Text Available The aim of this research project is the architecture and the design of an electronic system for controlling domestic tactile switches to be integrated into a home automation system based on the KNX standard. All the steps that led to the fulfillment of the finished prototype are reported, from the study and design of the capacitive tactile sensors and the electronic control board according to the specifications imposed by KNX standard. The touch event detection is reached as a trade-off with the footprint requirements of the switch. Experimental results of the fabricated prototype are presented to demonstrate the feasibility of this device.

  2. Experimental Manufacture and Performance Evaluation of Linear Switched Reluctance Motor with HTS Excitation Windings

    Science.gov (United States)

    Hirayama, Tadashi; Oto, Satoshi; Higashijima, Atsushi; Kawabata, Shuma

    This paper presents an experimental manufacture and performance evaluation of prototype linear switched reluctance motor with HTS excitation windings (HTS-LSRM). The Ag-alloy sheathed Bi-2223 tapes are used for HTS coils. We first present a structure of the prototype HTS-LSRM. Next, current-carrying properties of the HTS coils are measured. Furthermore, current and voltage waveforms are measured and we evaluation a control performance of the current and voltage.

  3. Implementation of Single Phase Soft Switched PFC Converter for Plug-in-Hybrid Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Aiswariya Sekar

    2015-11-01

    Full Text Available This paper presents a new soft switching boost converter with a passive snubber cell without additional active switches for battery charging systems. The proposed snubber finds its application in the front-end ac-dc converter of Plug-in Hybrid Electric Vehicle (PHEV battery chargers. The proposed auxiliary snubber circuit consists of an inductor, two capacitors and two diodes. The new converter has the advantages of continuous input current, low switching stresses, high voltage gain without extreme duty cycle, minimized charger size and charging time and fewer amounts of cost and electricity drawn from the utility at higher switching frequencies. The switch is made to turn ON by Zero Current Switching (ZCS and turn OFF by Zero Voltage Switching (ZVS. The detailed steady state analysis of the novel ac-dc Zero Current- Zero Voltage Switching (ZC-ZVS boost Power Factor Correction (PFC converter is presented with its operating principle. The experimental prototype of 20 kHz, 100 W converter verifies the theoretical analysis. The power factor of the prototype circuit reaches near unity with an efficiency of 97%, at nominal output power for a ±10% variation in the input voltage and ±20% variation in the snubber component values.

  4. Local Social Networks

    DEFF Research Database (Denmark)

    Sapuppo, Antonio; Sørensen, Lene Tolstrup

    2011-01-01

    in physical environment in order to leverage personal affinities in the users' surroundings. The purpose of this paper is to present and discuss the concept of local social networks as a new social communication system. Particularly, the preliminary architecture and the prototype of local social networks......Online social networks have become essential for many users in their daily communication. Through a combination of the online social networks with opportunistic networks, a new concept arises: Local Social Networks. The target of local social networks is to promote social networking benefits...

  5. Assessment of Zr-Fe-V getter alloy for gas-gap heat switches

    Science.gov (United States)

    Prina, M.; Kulleck, J. G.; Bowman, R. C., Jr.

    2000-01-01

    A commercial Zr-V-Fe alloy (i.e., SAES Getters trade name alloy St-172) has been assessed as reversible hydrogen storage material for use in actuators of gas gap heat switches. Two prototype actuators containing the SAES St-172 material were built and operated for several thousand cycles to evaluate performance of the metal hydride system under conditions simulating heat switch operation.

  6. Using MEMS Capacitive Switches in Tunable RF Amplifiers

    Directory of Open Access Journals (Sweden)

    Danson John

    2006-01-01

    Full Text Available A MEMS capacitive switch suitable for use in tunable RF amplifiers is described. A MEMS switch is designed, fabricated, and characterized with physical and RF measurements for inclusion in simulations. Using the MEMS switch models, a dual-band low-noise amplifier (LNA operating at GHz and GHz, and a tunable power amplifier (PA at GHz are simulated in m CMOS. MEMS switches allow the LNA to operate with 11 dB of isolation between the two bands while maintaining dB of gain and sub- dB noise figure. MEMS switches are used to implement a variable matching network that allows the PA to realize up to 37% PAE improvement at low input powers.

  7. Using MEMS Capacitive Switches in Tunable RF Amplifiers

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available A MEMS capacitive switch suitable for use in tunable RF amplifiers is described. A MEMS switch is designed, fabricated, and characterized with physical and RF measurements for inclusion in simulations. Using the MEMS switch models, a dual-band low-noise amplifier (LNA operating at 2.4 GHz and 5.2 GHz, and a tunable power amplifier (PA at 5.2 GHz are simulated in 0.18 μ m CMOS. MEMS switches allow the LNA to operate with 11 dB of isolation between the two bands while maintaining 11.6 dB of gain and sub- 4.5 dB noise figure. MEMS switches are used to implement a variable matching network that allows the PA to realize up to 37% PAE improvement at low input powers.

  8. Electric power supply I. Network elements, modelling, stationary network operation, dimensioning, switching and protective elements. 3. rev. ed.; Elektrische Energieversorgung I. Netzelemente, Modellierung, stationaeres Verhalten, Bemessung, Schalt- und Schutztechnik

    Energy Technology Data Exchange (ETDEWEB)

    Crastan, Valentin

    2012-07-01

    This is a detailed textbook and reference manual for students of electrotechnics and practical engineers. It is a synthesis between theory and practical relevance. The third edition of this textbook was updated and supplemented in its chapters 1 and 14. The text is supplemented by many exercises, model examples and simulations (MATLAB/SIMULINK). The author can look back at long years of experience as a professor of Berne University in Switzerland. Vol. 1 discusses the power supply grid, with particular regard to modern methods of modelling network element dynamics. In the 2nd edition those parts have been actualised and revised, which are affected by the energy-economical evolution and submitted by technological progress.

  9. Energy reversible switching from amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.

    2013-08-01

    We report observation of energy reversible switching from amorphous metal based nanoelectromechanical (NEM) switch. For ultra-low power electronics, NEM switches can be used as a complementary switching element in many nanoelectronic system applications. Its inherent zero power consumption because of mechanical detachment is an attractive feature. However, its operating voltage needs to be in the realm of 1 volt or lower. Appropriate design and lower Young\\'s modulus can contribute achieving lower operating voltage. Therefore, we have developed amorphous metal with low Young\\'s modulus and in this paper reporting the energy reversible switching from a laterally actuated double electrode NEM switch. © 2013 IEEE.

  10. Encapsulation of polymer photovoltaic prototypes

    DEFF Research Database (Denmark)

    Krebs, Frederik C

    2006-01-01

    A simple and efficient method for the encapsulation of polymer and organic photovoltaic prototypes is presented. The method employs device preparation on glass substrates with subsequent sealing using glass fiber reinforced thermosetting epoxy (prepreg) against a back plate. The method allows...

  11. Prototyping of user interfaces for mobile applications

    CERN Document Server

    Bähr, Benjamin

    2017-01-01

    This book investigates processes for the prototyping of user interfaces for mobile apps, and describes the development of new concepts and tools that can improve the prototype driven app development in the early stages. It presents the development and evaluation of a new requirements catalogue for prototyping mobile app tools that identifies the most important criteria such tools should meet at different prototype-development stages. This catalogue is not just a good point of orientation for designing new prototyping approaches, but also provides a set of metrics for a comparing the performance of alternative prototyping tools. In addition, the book discusses the development of Blended Prototyping, a new approach for prototyping user interfaces for mobile applications in the early and middle development stages, and presents the results of an evaluation of its performance, showing that it provides a tool for teamwork-oriented, creative prototyping of mobile apps in the early design stages.

  12. Prototype Effect and the Persuasiveness of Generalizations.

    Science.gov (United States)

    Dahlman, Christian; Sarwar, Farhan; Bååth, Rasmus; Wahlberg, Lena; Sikström, Sverker

    An argument that makes use of a generalization activates the prototype for the category used in the generalization. We conducted two experiments that investigated how the activation of the prototype affects the persuasiveness of the argument. The results of the experiments suggest that the features of the prototype overshadow and partly overwrite the actual facts of the case. The case is, to some extent, judged as if it had the features of the prototype instead of the features it actually has. This prototype effect increases the persuasiveness of the argument in situations where the audience finds the judgment more warranted for the prototype than for the actual case (positive prototype effect), but decreases persuasiveness in situations where the audience finds the judgment less warranted for the prototype than for the actual case (negative prototype effect).

  13. Switching memory perspective.

    Science.gov (United States)

    Akhtar, Shazia; Justice, Lucy V; Loveday, Catherine; Conway, Martin A

    2017-11-01

    The perspective in which memories were spontaneously recalled, field (original perspective) or observer (see oneself in the memory), was examined for both recent and remote memories. Recent memories were dominated by field perspective whilst remote memories were dominated by observer perspective. Further, field memories contained reliably more episodic detail than observer memories. After a 1-week interval, the same memories were recalled again but with a switched memory perspective. Switching from an observer to a field perspective did not reliably increase the amount of episodic details in a memory. Switching from field to observer perspective did, however, reliably reduce the number of episodic details. These findings suggest that memories may be represented in long-term memory with a fixed perspective, either field or observer, which can be temporarily altered sometimes changing the nature of a memory, i.e. how much detail remains accessible. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  14. Microfabricated triggered vacuum switch

    Science.gov (United States)

    Roesler, Alexander W [Tijeras, NM; Schare, Joshua M [Albuquerque, NM; Bunch, Kyle [Albuquerque, NM

    2010-05-11

    A microfabricated vacuum switch is disclosed which includes a substrate upon which an anode, cathode and trigger electrode are located. A cover is sealed over the substrate under vacuum to complete the vacuum switch. In some embodiments of the present invention, a metal cover can be used in place of the trigger electrode on the substrate. Materials used for the vacuum switch are compatible with high vacuum, relatively high temperature processing. These materials include molybdenum, niobium, copper, tungsten, aluminum and alloys thereof for the anode and cathode. Carbon in the form of graphitic carbon, a diamond-like material, or carbon nanotubes can be used in the trigger electrode. Channels can be optionally formed in the substrate to mitigate against surface breakdown.

  15. Prototype diagnosis of psychiatric syndromes

    Science.gov (United States)

    WESTEN, DREW

    2012-01-01

    The method of diagnosing patients used since the early 1980s in psychiatry, which involves evaluating each of several hundred symptoms for their presence or absence and then applying idiosyncratic rules for combining them for each of several hundred disorders, has led to great advances in research over the last 30 years. However, its problems have become increasingly apparent, particularly for clinical practice. An alternative approach, designed to maximize clinical utility, is prototype matching. Instead of counting symptoms of a disorder and determining whether they cross an arbitrary cutoff, the task of the diagnostician is to gauge the extent to which a patient’s clinical presentation matches a paragraph-length description of the disorder using a simple 5-point scale, from 1 (“little or no match”) to 5 (“very good match”). The result is both a dimensional diagnosis that captures the extent to which the patient “has” the disorder and a categorical diagnosis, with ratings of 4 and 5 corresponding to presence of the disorder and a rating of 3 indicating “subthreshold” or “clinically significant features”. The disorders and criteria woven into the prototypes can be identified empirically, so that the prototypes are both scientifically grounded and clinically useful. Prototype diagnosis has a number of advantages: it better captures the way humans naturally classify novel and complex stimuli; is clinically helpful, reliable, and easy to use in everyday practice; facilitates both dimensional and categorical diagnosis and dramatically reduces the number of categories required for classification; allows for clinically richer, empirically derived, and culturally relevant classification; reduces the gap between research criteria and clinical knowledge, by allowing clinicians in training to learn a small set of standardized prototypes and to develop richer mental representations of the disorders over time through clinical experience; and can help

  16. Architectural Considerations for Photonic Switching Networks

    OpenAIRE

    Hinton, Harvard S.

    1988-01-01

    Photonic technologies are reviewed that could become important components of future telecommunication systems. Photonic devices and systems are divided into two classes according to the function they perform. The first class, relational, refers to devices, that map the input channels to the output channels under external control. The second class, logic, perform some type or combination of Boolean logic functions. Some of the strengths and weaknesses of operating in the photonic domain are pr...

  17. Modeling Switched Circuit Network Systems Using PLANITU

    Science.gov (United States)

    2005-12-01

    seen from ITU-D (from [10]) .........33 Figure 5.1. Funcional block diagram showing FcMetro data processing and results generated (from [1...seen from Figure 2.1 input variables consist of a general traffic forecast, traffic patterns, technical constraints, and cost models. 4 Figure 2.1...scenario • Design, dimensioning, location and costing • Optimization • Sensitivity analysis to uncertain variables • Plan selection and

  18. Characterizing multistationarity regimes in biochemical reaction networks

    OpenAIRE

    Irene Otero-Muras; Julio R. Banga; Alonso, Antonio A

    2012-01-01

    Switch like responses appear as common strategies in the regulation of cellular systems. Here we present a method to characterize bistable regimes in biochemical reaction networks that can be of use to both direct and reverse engineering of biological switches. In the design of a synthetic biological switch, it is important to study the capability for bistability of the underlying biochemical network structure. Chemical Reaction Network Theory (CRNT) may help at this level to decide whether a...

  19. An interplay of fusiform gyrus and hippocampus enables prototype- and exemplar-based category learning.

    Science.gov (United States)

    Lech, Robert K; Güntürkün, Onur; Suchan, Boris

    2016-09-15

    The aim of the present study was to examine the contributions of different brain structures to prototype- and exemplar-based category learning using functional magnetic resonance imaging (fMRI). Twenty-eight subjects performed a categorization task in which they had to assign prototypes and exceptions to two different families. This test procedure usually produces different learning curves for prototype and exception stimuli. Our behavioral data replicated these previous findings by showing an initially superior performance for prototypes and typical stimuli and a switch from a prototype-based to an exemplar-based categorization for exceptions in the later learning phases. Since performance varied, we divided participants into learners and non-learners. Analysis of the functional imaging data revealed that the interaction of group (learners vs. non-learners) and block (Block 5 vs. Block 1) yielded an activation of the left fusiform gyrus for the processing of prototypes, and an activation of the right hippocampus for exceptions after learning the categories. Thus, successful prototype- and exemplar-based category learning is associated with activations of complementary neural substrates that constitute object-based processes of the ventral visual stream and their interaction with unique-cue representations, possibly based on sparse coding within the hippocampus. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Optical Packet Switch Architectures

    Science.gov (United States)

    Singh, Rajat Kumar; Srivastava, Rajiv; Singh, Yatindra Nath

    In this article, we present the comparative analysis of various optical packet switch architectures. The comparison is done on the basis of bursty traffic arrival and the optical cost of various optical components used to build that switch. The architectures chosen for the analysis were previously proposed by us and their performance was evaluated only for the uniform random traffic arrival. Hence, this article can be considered as the cumulative and effective extension of the previous works. The computer simulations are performed to obtain the packet loss probability and average delay in presence of bursty traffic.