WorldWideScience

Sample records for switched network based

  1. Optical burst switching based satellite backbone network

    Science.gov (United States)

    Li, Tingting; Guo, Hongxiang; Wang, Cen; Wu, Jian

    2018-02-01

    We propose a novel time slot based optical burst switching (OBS) architecture for GEO/LEO based satellite backbone network. This architecture can provide high speed data transmission rate and high switching capacity . Furthermore, we design the control plane of this optical satellite backbone network. The software defined network (SDN) and network slice (NS) technologies are introduced. Under the properly designed control mechanism, this backbone network is flexible to support various services with diverse transmission requirements. Additionally, the LEO access and handoff management in this network is also discussed.

  2. 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.

  3. 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.

  4. Novel flat datacenter network architecture based on scalable and flow-controlled optical switch system

    NARCIS (Netherlands)

    Miao, W.; Luo, J.; Di Lucente, S.; Dorren, H.J.S.; Calabretta, N.

    2013-01-01

    We propose and demonstrate an optical flat datacenter network based on scalable optical switch system with optical flow control. 4×4 dynamic switch operation at 40 Gb/s reported 300ns minimum end-to-end latency (including 25m transmission link) and

  5. 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.

  6. Optical packet switched networks

    DEFF Research Database (Denmark)

    Hansen, Peter Bukhave

    1999-01-01

    Optical packet switched networks are investigated with emphasis on the performance of the packet switch blocks. Initially, the network context of the optical packet switched network is described showing that a packet network will provide transparency, flexibility and bridge the granularity gap...... 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...... is established as a flexible means to reduce the optical buffer, e.g., the number of fibre delay lines for a 16x16 switch block is reduced from 23 to 6 by going from 2 to 8 wavelength channels pr. inlet. Additionally, a component count analysis is carried out to illustrate the trade-offs in the switch block...

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. Circuit switched optical networks

    DEFF Research Database (Denmark)

    Kloch, Allan

    2003-01-01

    Some of the most important components required for enabling optical networking are investigated through both experiments and modelling. These all-optical components are the wavelength converter, the regenerator and the space switch. When these devices become "off-the-shelf" products, optical cross......, 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...

  14. Novel flat datacenter network architecture based on scalable and flow-controlled optical switch system.

    Science.gov (United States)

    Miao, Wang; Luo, Jun; Di Lucente, Stefano; Dorren, Harm; Calabretta, Nicola

    2014-02-10

    We propose and demonstrate an optical flat datacenter network based on scalable optical switch system with optical flow control. Modular structure with distributed control results in port-count independent optical switch reconfiguration time. RF tone in-band labeling technique allowing parallel processing of the label bits ensures the low latency operation regardless of the switch port-count. Hardware flow control is conducted at optical level by re-using the label wavelength without occupying extra bandwidth, space, and network resources which further improves the performance of latency within a simple structure. Dynamic switching including multicasting operation is validated for a 4 x 4 system. Error free operation of 40 Gb/s data packets has been achieved with only 1 dB penalty. The system could handle an input load up to 0.5 providing a packet loss lower that 10(-5) and an average latency less that 500 ns when a buffer size of 16 packets is employed. Investigation on scalability also indicates that the proposed system could potentially scale up to large port count with limited power penalty.

  15. Optical computer switching network

    Science.gov (United States)

    Clymer, B.; Collins, S. A., Jr.

    1985-01-01

    The design for an optical switching system for minicomputers that uses an optical spatial light modulator such as a Hughes liquid crystal light valve is presented. The switching system is designed to connect 80 minicomputers coupled to the switching system by optical fibers. The system has two major parts: the connection system that connects the data lines by which the computers communicate via a two-dimensional optical matrix array and the control system that controls which computers are connected. The basic system, the matrix-based connecting system, and some of the optical components to be used are described. Finally, the details of the control system are given and illustrated with a discussion of timing.

  16. All-fiber optical mode switching based on cascaded mode selective couplers for short-reach MDM networks

    Science.gov (United States)

    Ren, Fang; Li, Juhao; Wu, Zhongying; Yu, Jinyi; Mo, Qi; Wang, Jianping; He, Yongqi; Chen, Zhangyuan; Li, Zhengbin

    2017-04-01

    We propose and experimentally demonstrate an all-fiber optical mode switching structure supporting independent switching, exchanging, adding, and dropping functionalities in which each mode can be switched individually. The mode switching structure consists of cascaded mode selective couplers (MSCs) capable of exciting and selecting specific higher order modes in few-mode fibers with high efficiency and one multiport optical switch routing the independent spatial modes to their destinations. The data carried on three different spatial modes can be switched, exchanged, added, and dropped through this all-fiber structure. For this experimental demonstration, optical on-off-keying (OOK) signals at 10-Gb/s carried on three spatial modes are successfully processed with open and clear eye diagrams. The mode switch exhibits power penalties of less than 3.1 dB after through operation, less than 2.7 dB after exchange operation, less than 2.8 dB after switching operation, and less than 1.6 dB after mode adding and dropping operations at the bit-error rate (BER) of 10-3, while all three channels carried on three spatial modes are simultaneously routed. The proposed structure, compatible with current optical switching networks based on single-mode fibers, can potentially be used to expand the switching scalability in advanced and flexible short-reach mode-division multiplexing-based networks.

  17. Optical Multidimensional Switching for Data Center Networks

    DEFF Research Database (Denmark)

    Kamchevska, Valerija

    2017-01-01

    . 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...... for the purpose of deploying optical switching within the network. First, the Hi-Ring data center architecture is proposed. It is based on optical multidimensional switching nodes that provide switching in hierarchically layered space, wavelength and time domain. The performance of the Hi-Ring architecture...... is evaluated experimentally and successful switching of both high capacity wavelength connections and time-shared subwavelengthconnections is demonstrated. Error-free performance is also achieved when transmitting 7 Tbit/s using multicore fiber, confirming the ability to scale the network. Moreover...

  18. Stateless multicast switching in software defined networks

    OpenAIRE

    Reed, Martin J.; Al-Naday, Mays; Thomos, Nikolaos; Trossen, Dirk; Petropoulos, George; Spirou, Spiros

    2016-01-01

    Multicast data delivery can significantly reduce traffic in operators' networks, but has been limited in deployment due to concerns such as the scalability of state management. This paper shows how multicast can be implemented in contemporary software defined networking (SDN) switches, with less state than existing unicast switching strategies, by utilising a Bloom Filter (BF) based switching technique. Furthermore, the proposed mechanism uses only proactive rule insertion, and thus, is not l...

  19. 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

    -flow based resource binding algorithm based on breadth-first search (BFS) and minimum cost maximum flow (MCMF) in architectural-level synthesis. The experimental results show that our methodology not only makes significant reduction of valve-switching activities but also diminishes the application completion......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...... 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...

  20. An intelligent switch with back-propagation neural network based hybrid power system

    Science.gov (United States)

    Perdana, R. H. Y.; Fibriana, F.

    2018-03-01

    The consumption of conventional energy such as fossil fuels plays the critical role in the global warming issues. The carbon dioxide, methane, nitrous oxide, etc. could lead the greenhouse effects and change the climate pattern. In fact, 77% of the electrical energy is generated from fossil fuels combustion. Therefore, it is necessary to use the renewable energy sources for reducing the conventional energy consumption regarding electricity generation. This paper presents an intelligent switch to combine both energy resources, i.e., the solar panels as the renewable energy with the conventional energy from the State Electricity Enterprise (PLN). The artificial intelligence technology with the back-propagation neural network was designed to control the flow of energy that is distributed dynamically based on renewable energy generation. By the continuous monitoring on each load and source, the dynamic pattern of the intelligent switch was better than the conventional switching method. The first experimental results for 60 W solar panels showed the standard deviation of the trial at 0.7 and standard deviation of the experiment at 0.28. The second operation for a 900 W of solar panel obtained the standard deviation of the trial at 0.05 and 0.18 for the standard deviation of the experiment. Moreover, the accuracy reached 83% using this method. By the combination of the back-propagation neural network with the observation of energy usage of the load using wireless sensor network, each load can be evenly distributed and will impact on the reduction of conventional energy usage.

  1. Efficient IP Traffic over Optical Network Based on Wavelength Translation Switching

    DEFF Research Database (Denmark)

    Jha, Vikas; Kalia, Kartik; Chowdhary, Bhawani Shankar

    2016-01-01

    With the advent of TCP/IP protocol suite the overall era of communication technologies had been redefined. Now, we can’t ignore the presence of huge amount of IP traffic; data, voice or video increasing day by day creating more pressure on existing communicating media and supporting back bone....... With the humongous popularity of Internet the overall traffic on Internet has the same story. Focusing on transmission of IP traffic in an optical network with signals remaining in their optical nature generated at particular wavelength, proposed is the switching of optically generated IP packets through optical...... cross connects based on translation of wavelength when an IP packet is crossing the optical cross connect. Adding the concepts of layer 3 routing protocols along with the wavelength translation scheme, will help in spanning the overall optical network for a larger area....

  2. 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.

  3. 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.

  4. 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.

  5. Improving Energy Efficiency of Cooperative Femtocell Networks via Base Station Switching Off

    Directory of Open Access Journals (Sweden)

    Woongsup Lee

    2016-01-01

    Full Text Available Recently, energy efficiency (EE of cellular networks has become an important performance metric, and several techniques have been proposed to increase the EE. Among them, turning off base stations (BSs when not needed is considered as one of the most powerful techniques due to its simple operation and effectiveness. Herein, we propose a novel BS switching-off technique for cooperative femtocell networks where multiple femtocell BSs (FBSs simultaneously send packets to the same mobile station (MS. Unlike conventional schemes, cooperative operation of FBSs, also known as coordinated multipoint (CoMP transmission, is considered to determine which BSs are turned off in the proposed technique. We first formulate the optimization problem to find the optimal set of FBSs to be turned off. Then, we propose a suboptimal scheme operating in a distributed manner in order to reduce the computational complexity of the optimal scheme. The suboptimal scheme is based on throughput ratio (TR which specifies the importance of a particular FBS for the cooperative transmission. Through simulations, we show that the energy consumption can be greatly reduced with the proposed technique, compared with conventional schemes. Moreover, we show that the suboptimal scheme also achieves the near-optimal performance even without the excessive computations.

  6. 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

  7. 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.

  8. A Lossless Switch for Data Acquisition Networks

    CERN Document Server

    Jereczek, Grzegorz Edmund; 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...

  9. 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.

  10. 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.

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

    NARCIS (Netherlands)

    Calabretta, N.; Miao, W.; Dorren, H.J.S.

    2015-01-01

    We demonstrate a reconfigurable virtual datacenter network by utilizing statistical multiplexing offered by scalable and flow-controlled optical switching system. Results show QoS guarantees by the priority assignment and load balancing for applications in virtual networks.

  12. 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.......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....

  13. Sampled-data consensus in switching networks of integrators based on edge events

    Science.gov (United States)

    Xiao, Feng; Meng, Xiangyu; Chen, Tongwen

    2015-02-01

    This paper investigates the event-driven sampled-data consensus in switching networks of multiple integrators and studies both the bidirectional interaction and leader-following passive reaction topologies in a unified framework. In these topologies, each information link is modelled by an edge of the information graph and assigned a sequence of edge events, which activate the mutual data sampling and controller updates of the two linked agents. Two kinds of edge-event-detecting rules are proposed for the general asynchronous data-sampling case and the synchronous periodic event-detecting case. They are implemented in a distributed fashion, and their effectiveness in reducing communication costs and solving consensus problems under a jointly connected topology condition is shown by both theoretical analysis and simulation examples.

  14. 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.

  15. Synchronization in complex networks with switching topology

    International Nuclear Information System (INIS)

    Wang, Lei; Wang, Qing-guo

    2011-01-01

    This Letter investigates synchronization issues of complex dynamical networks with switching topology. By constructing a common Lyapunov function, we show that local and global synchronization for a linearly coupled network with switching topology can be evaluated by the time average of second smallest eigenvalues corresponding to the Laplacians of switching topology. This result is quite powerful and can be further used to explore various switching cases for complex dynamical networks. Numerical simulations illustrate the effectiveness of the obtained results in the end. -- Highlights: → Synchronization of complex networks with switching topology is investigated. → A common Lyapunov function is established for synchronization of switching network. → The common Lyapunov function is not necessary to monotonically decrease with time. → Synchronization is determined by the second smallest eigenvalue of its Laplacian. → Synchronization criterion can be used to investigate various switching cases.

  16. 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.

  17. 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.

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

    KAUST Repository

    Ghazzai, Hakim; Farooq, Muhammad Junaid; Alsharoa, Ahmad; Yaacoub, Elias; Kadri, Abdullah; Alouini, Mohamed-Slim

    2016-01-01

    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.

  19. 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.

  20. 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...

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

    DEFF Research Database (Denmark)

    Park, Kiwoo

    enable various renewable energy sources, such as Photovoltaic (PV) and wind, to produce dc power directly. In addition, battery-based energy storage systems inherently operate with dc power. Hence, dc network (dc-grid) systems which connect these dc sources and storages directly using dc networks...... are gaining much attention again. The dc network system has a great potential to outdo the traditional ac systems in many technical challenges and could be highly profitable especially for offshore wind farm applications, where the size and weight of the components are crucial to the entire system costs......Wind power technology, as the most competitive renewable energy technology, is quickly developing. The wind turbine size is growing and the grid penetration of wind power is increasing rapidly. Recently, the developments on wind power technology pay more attentions on efficiency and reliability...

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

    OpenAIRE

    Cao, Jinde; Alofi, Abdulaziz; Al-Mazrooei, Abdullah; Elaiw, Ahmed

    2013-01-01

    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, synchroniza...

  3. 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.

  4. 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

  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......, as for example a transmission line. Both methods require that harmonic measurements performed at two ends of the disconnected element are precisely synchronized....... 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...

  6. Clustering promotes switching dynamics in networks of noisy neurons

    Science.gov (United States)

    Franović, Igor; Klinshov, Vladimir

    2018-02-01

    Macroscopic variability is an emergent property of neural networks, typically manifested in spontaneous switching between the episodes of elevated neuronal activity and the quiescent episodes. We investigate the conditions that facilitate switching dynamics, focusing on the interplay between the different sources of noise and heterogeneity of the network topology. We consider clustered networks of rate-based neurons subjected to external and intrinsic noise and derive an effective model where the network dynamics is described by a set of coupled second-order stochastic mean-field systems representing each of the clusters. The model provides an insight into the different contributions to effective macroscopic noise and qualitatively indicates the parameter domains where switching dynamics may occur. By analyzing the mean-field model in the thermodynamic limit, we demonstrate that clustering promotes multistability, which gives rise to switching dynamics in a considerably wider parameter region compared to the case of a non-clustered network with sparse random connection topology.

  7. A microcomputer for a packet switched network

    International Nuclear Information System (INIS)

    Seller, P.; Bairstow, R.; Barlow, J.; Waters, M.

    1982-12-01

    The Bubble Chamber Research Group of the Rutherford and Appleton Laboratory has a large film analysis facility. This comprises 16 digitising tables used for the measurement of bubble chamber film. Each of these tables has an associated microcomputer. These microcomputers are linked by a star structured packet switched local area network (LAN) to a VAX 11/780. The LAN, and in particular a microcomputer of novel architecture designed to act as the central switch of the network, is described. (author)

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

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh; Alouini, Mohamed-Slim

    2012-01-01

    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

  9. A Performance Analysis for UMTS Packet Switched Network Based on Multivariate KPIS

    OpenAIRE

    Ouyang, Ye; Fallah, M. Hosein

    2010-01-01

    Mobile data services are penetrating mobile markets rapidly. The mobile industry relies heavily on data service to replace the traditional voice services with the evolution of the wireless technology and market. A reliable packet service network is critical to the mobile operators to maintain their core competence in data service market. Furthermore, mobile operators need to develop effective operational models to manage the varying mix of voice, data and video traffic on a single network. Ap...

  10. Software-defined networking control plane for seamless integration of multiple silicon photonic switches in Datacom networks.

    Science.gov (United States)

    Shen, Yiwen; Hattink, Maarten H N; Samadi, Payman; Cheng, Qixiang; Hu, Ziyiz; Gazman, Alexander; Bergman, Keren

    2018-04-16

    Silicon photonics based switches offer an effective option for the delivery of dynamic bandwidth for future large-scale Datacom systems while maintaining scalable energy efficiency. The integration of a silicon photonics-based optical switching fabric within electronic Datacom architectures requires novel network topologies and arbitration strategies to effectively manage the active elements in the network. We present a scalable software-defined networking control plane to integrate silicon photonic based switches with conventional Ethernet or InfiniBand networks. Our software-defined control plane manages both electronic packet switches and multiple silicon photonic switches for simultaneous packet and circuit switching. We built an experimental Dragonfly network testbed with 16 electronic packet switches and 2 silicon photonic switches to evaluate our control plane. Observed latencies occupied by each step of the switching procedure demonstrate a total of 344 µs control plane latency for data-center and high performance computing platforms.

  11. 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.

  12. 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...

  13. 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.

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

    KAUST Repository

    Benkhelifa, Fatma; Alouini, Mohamed-Slim

    2017-01-01

    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.

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

    KAUST Repository

    Benkhelifa, Fatma; Alouini, Mohamed-Slim

    2016-01-01

    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.

  16. 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.

  17. 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.

  18. 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.

  19. Optical Multidimensional Switching for Data Center Networks

    OpenAIRE

    Kamchevska, Valerija; Galili, Michael; Oxenløwe, Leif Katsuo; Berger, Michael Stübert

    2017-01-01

    Optical switches are known for the ability to provide high bandwidth connectivity at a relatively low power consumption and low latency. Several recent demonstrations on optical data center architectures confirm the potential for introducing all-optical switching within the data center, thus 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 u...

  20. Compensation of position errors in passivity based teleoperation over packet switched communication networks

    NARCIS (Netherlands)

    Secchi, C; Stramigioli, Stefano; Fantuzzi, C.

    Because of the use of scattering based communication channels, passivity based telemanipulation systems can be subject to a steady state position error between master and slave robots. In this paper, we consider the case in which the passive master and slave sides communicate through a packet

  1. Uji Performa Software-based Openflow Switch Berbasis Openwrt

    OpenAIRE

    Kartadie, Rikie; Suryanto, Tommy

    2015-01-01

    Perkembangan pesat Software-Defined Network telah dirasakan oleh vendor vendor besar. HP, Google dan IBM, mulai merubah pola routing-switching pada network mereka dari pola routingswitching tradisional ke pola infrastruktur routing-switching Software-defined Network. Untuk melakukan eksperimen tentang OpenFlow, para peneliti sering kali harus menggunakan perangkat hardware/dedicated switch OpenFlow yang dikeluarkan oleh beberapa vendor dengan harga yang tinggi. Kenyataannya, software-based sw...

  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. A novel scalable and low latency hybrid data center network architecture based on flow controlled fast optical switches

    NARCIS (Netherlands)

    Yan, Fulong; Guelbenzu, Gonzalo; Calabretta, Nicola

    2018-01-01

    We present a novel hybrid DCN based on flow-controlled fast optical switches. Results show packet loss < 1.4E-5 and latency < 2.4μs for 100,000 servers (0.3 load). Costs and power consumptions are also compared with current technologies.

  4. Delayed switching applied to memristor neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Frank Z.; Yang Xiao; Lim Guan [Future Computing Group, School of Computing, University of Kent, Canterbury (United Kingdom); Helian Na [School of Computer Science, University of Hertfordshire, Hatfield (United Kingdom); Wu Sining [Xyratex, Havant (United Kingdom); Guo Yike [Department of Computing, Imperial College, London (United Kingdom); Rashid, Md Mamunur [CERN, Geneva (Switzerland)

    2012-04-01

    Magnetic flux and electric charge are linked in a memristor. We reported recently that a memristor has a peculiar effect in which the switching takes place with a time delay because a memristor possesses a certain inertia. This effect was named the ''delayed switching effect.'' In this work, we elaborate on the importance of delayed switching in a brain-like computer using memristor neural networks. The effect is used to control the switching of a memristor synapse between two neurons that fire together (the Hebbian rule). A theoretical formula is found, and the design is verified by a simulation. We have also built an experimental setup consisting of electronic memristive synapses and electronic neurons.

  5. Delayed switching applied to memristor neural networks

    International Nuclear Information System (INIS)

    Wang, Frank Z.; Yang Xiao; Lim Guan; Helian Na; Wu Sining; Guo Yike; Rashid, Md Mamunur

    2012-01-01

    Magnetic flux and electric charge are linked in a memristor. We reported recently that a memristor has a peculiar effect in which the switching takes place with a time delay because a memristor possesses a certain inertia. This effect was named the ''delayed switching effect.'' In this work, we elaborate on the importance of delayed switching in a brain-like computer using memristor neural networks. The effect is used to control the switching of a memristor synapse between two neurons that fire together (the Hebbian rule). A theoretical formula is found, and the design is verified by a simulation. We have also built an experimental setup consisting of electronic memristive synapses and electronic neurons.

  6. Modeling and Analysis of Modal Switching in Networked Transport Systems

    International Nuclear Information System (INIS)

    Hante, Falk M.; Leugering, Guenter; Seidman, Thomas I.

    2009-01-01

    We consider networked transport systems defined on directed graphs: the dynamics on the edges correspond to solutions of transport equations with space dimension one. In addition to the graph setting, a major consideration is the introduction and propagation of discontinuities in the solutions when the system may discontinuously switch modes, naturally or as a hybrid control. This kind of switching has been extensively studied for ordinary differential equations, but not much so far for systems governed by partial differential equations. In particular, we give well-posedness results for switching as a control, both in finite horizon open loop operation and as feedback based on sensor measurements in the system

  7. Energy reversible switching from amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.; Smith, Casey; Hussain, Muhammad Mustafa

    2013-01-01

    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.

  8. 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.

  9. Amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.; Smith, Casey; Hussain, Muhammad Mustafa

    2013-01-01

    Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

  10. Amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.

    2013-04-01

    Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

  11. Node design in optical packet switched networks

    DEFF Research Database (Denmark)

    Nord, Martin

    2006-01-01

    The thesis discusses motivation, realisation and performance of the Optical Packet Switching (OPS) network paradigm. The work includes proposals for designs and methods to efficiently use both the wavelength- and time domain for contention resolution in asynchronous operation. The project has also......S parameter. Finally, the thesis includes a proposal for a node design and associated MAC protocol for an OPS ring topology metropolitan area network with high throughput and fairness, also for unbalanced traffic....... proposed parallel designs to overcome scalability constraints and to support migration scenarios. Furthermore, it has proposed and demonstrated optical input processing schemes for hybrids networks to simultaneously support OPS and Optical Circuit Switching. Quality of Service (QoS) differentiation enables...

  12. Robust stability analysis of switched Hopfield neural networks with time-varying delay under uncertainty

    International Nuclear Information System (INIS)

    Huang He; Qu Yuzhong; Li Hanxiong

    2005-01-01

    With the development of intelligent control, switched systems have been widely studied. Here we try to introduce some ideas of the switched systems into the field of neural networks. In this Letter, a class of switched Hopfield neural networks with time-varying delay is investigated. The parametric uncertainty is considered and assumed to be norm bounded. Firstly, the mathematical model of the switched Hopfield neural networks is established in which a set of Hopfield neural networks are used as the individual subsystems and an arbitrary switching rule is assumed; Secondly, robust stability analysis for such switched Hopfield neural networks is addressed based on the Lyapunov-Krasovskii approach. Some criteria are given to guarantee the switched Hopfield neural networks to be globally exponentially stable for all admissible parametric uncertainties. These conditions are expressed in terms of some strict linear matrix inequalities (LMIs). Finally, a numerical example is provided to illustrate our results

  13. OpenFlow Switching Performance using Network Simulator - 3

    OpenAIRE

    Sriram Prashanth, Naguru

    2016-01-01

    Context. In the present network inventive world, there is a quick expansion of switches and protocols, which are used to cope up with the increase in customer requirement in the networking. With increasing demand for higher bandwidths and lower latency and to meet these requirements new network paths are introduced. To reduce network load in present switching network, development of new innovative switching is required. These required results can be achieved by Software Define Network or Trad...

  14. Concave switching in single-hop and multihop networks

    NARCIS (Netherlands)

    Walton, N.

    2015-01-01

    Switched queueing networks model wireless networks, input-queued switches, and numerous other networked communications systems. We consider an (\\(\\alpha ,g\\))-switch policy; these policies provide a generalization of the MaxWeight policies of Tassiulas and Ephremides (IEEE Trans Autom Control

  15. Atomic switch networks as complex adaptive systems

    Science.gov (United States)

    Scharnhorst, Kelsey S.; Carbajal, Juan P.; Aguilera, Renato C.; Sandouk, Eric J.; Aono, Masakazu; Stieg, Adam Z.; Gimzewski, James K.

    2018-03-01

    Complexity is an increasingly crucial aspect of societal, environmental and biological phenomena. Using a dense unorganized network of synthetic synapses it is shown that a complex adaptive system can be physically created on a microchip built especially for complex problems. These neuro-inspired atomic switch networks (ASNs) are a dynamic system with inherent and distributed memory, recurrent pathways, and up to a billion interacting elements. We demonstrate key parameters describing self-organized behavior such as non-linearity, power law dynamics, and multistate switching regimes. Device dynamics are then investigated using a feedback loop which provides control over current and voltage power-law behavior. Wide ranging prospective applications include understanding and eventually predicting future events that display complex emergent behavior in the critical regime.

  16. Error rate degradation due to switch crosstalk in large modular switched optical networks

    DEFF Research Database (Denmark)

    Saxtoft, Christian; Chidgey, P.

    1993-01-01

    A theoretical model of an optical network incorporating wavelength selective elements, amplifiers, couplers and switches is presented. The model is used to evaluate a large modular switch optical network that provides the capability of adapting easily to changes in network traffic requirements. T....... The network dimensions are shown to be limited by the optical crosstalk in the switch matrices and by the polarization dependent loss in the optical components...

  17. Switching Fuzzy Guaranteed Cost Control for Nonlinear Networked Control Systems

    Directory of Open Access Journals (Sweden)

    Linqin Cai

    2014-01-01

    Full Text Available This paper deals with the problem of guaranteed cost control for a class of nonlinear networked control systems (NCSs with time-varying delay. A guaranteed cost controller design method is proposed to achieve the desired control performance based on the switched T-S fuzzy model. The switching mechanism is introduced to handle the uncertainties of NCSs. Based on Lyapunov functional approach, some sufficient conditions for the existence of state feedback robust guaranteed cost controller are presented. Simulation results show that the proposed method is effective to guarantee system’s global asymptotic stability and quality of service (QoS.

  18. 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...... attractive when traffic is unbalanced....

  19. All-optical packet/circuit switching-based data center network for enhanced scalability, latency and throughput

    NARCIS (Netherlands)

    Perelló, J.; Spadaro, S.; Ricciardi, S.; Careglio, D.; Peng, S.; Nejabati, R.; Zervas, G.; Simeonidou, D.; Predieri, A.; Biancani, M.; Dorren, H.J.S.; Di Lucente, S.; Luo, J.; Calabretta, N.; Bernini, G.; Ciulli, N.; Sancho, J.C.; Iordache, S.; Farreras, M.; Becerra, Y.; Liou, C.; Hussain, I.; Yin, Y.; Liu, L.; Proietti, R.

    2013-01-01

    Applications running inside data centers are enabled through the cooperation of thousands of servers arranged in racks and interconnected together through the data center network. Current DCN architectures based on electronic devices are neither scalable to face the massive growth of DCs, nor

  20. 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

  1. Architectures of electro-optical packet switched networks

    DEFF Research Database (Denmark)

    Berger, Michael Stubert

    2004-01-01

    and examines possible architectures for future high capacity networks with high capacity nodes. It is assumed that optics will play a key role in this scenario, and in this respect, the European IST research project DAVID aimed at proposing viable architectures for optical packet switching, exploiting the best...... from optics and electronics. An overview of the DAVID network architecture is given, focusing on the MAN and WAN architecture as well as the MPLS based network hierarchy. A statistical model of the optical slot generation process is presented and utilised to evaluate delay vs. efficiency. Furthermore...... architecture for a buffered crossbar switch is presented. The architecture uses two levels of backpressure (flow control) with different constraints on round trip time. No additional scheduling complexity is introduced, and for the actual example shown, a reduction in memory of 75% was obtained at the cost...

  2. 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).

  3. 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.

  4. 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.

  5. All-optical signal processing for optical packet switching networks

    NARCIS (Netherlands)

    Liu, Y.; Hill, M.T.; Calabretta, N.; Tangdiongga, E.; Geldenhuys, R.; Zhang, S.; Li, Z.; Waardt, de H.; Khoe, G.D.; Dorren, H.J.S.; Iftekharuddin, K.M.; awwal, A.A.S.

    2005-01-01

    We discuss how all-optical signal processing might play a role in future all-optical packet switched networks. We introduce a concept of optical packet switches that employ entirely all-optical signal processing technology. The optical packet switch is made out of three functional blocks: the

  6. Average contraction and synchronization of complex switched networks

    International Nuclear Information System (INIS)

    Wang Lei; Wang Qingguo

    2012-01-01

    This paper introduces an average contraction analysis for nonlinear switched systems and applies it to investigating the synchronization of complex networks of coupled systems with switching topology. For a general nonlinear system with a time-dependent switching law, a basic convergence result is presented according to average contraction analysis, and a special case where trajectories of a distributed switched system converge to a linear subspace is then investigated. Synchronization is viewed as the special case with all trajectories approaching the synchronization manifold, and is thus studied for complex networks of coupled oscillators with switching topology. It is shown that the synchronization of a complex switched network can be evaluated by the dynamics of an isolated node, the coupling strength and the time average of the smallest eigenvalue associated with the Laplacians of switching topology and the coupling fashion. Finally, numerical simulations illustrate the effectiveness of the proposed methods. (paper)

  7. Compact wireless control network protocol with fast path switching

    Directory of Open Access Journals (Sweden)

    Yasutaka Kawamoto

    2017-08-01

    Full Text Available Sensor network protocol stacks require the addition or adjustment of functions based on customer requirements. Sensor network protocols that require low delay and low packet error rate (PER, such as wireless control networks, often adopt time division multiple access (TDMA. However, it is difficult to add or adjust functions in protocol stacks that use TDMA methods. Therefore, to add or adjust functions easily, we propose NES-SOURCE, a compact wireless control network protocol with a fast path-switching function. NES-SOURCE is implemented using carrier sense multiple access/collision avoidance (CSMA/CA rather than TDMA. Wireless control networks that use TDMA prevent communication failure by duplicating the communication path. If CSMA/CA networks use duplicate paths, collisions occur frequently, and communication will fail. NES-SOURCE switches paths quickly when communication fails, which reduces the effect of communication failures. Since NES-SOURCE is implemented using CSMA/CA rather than TDMA, the implementation scale is less than one-half that of existing network stacks. Furthermore, since NES-SOURCE’s code complexity is low, functions can be added or adjusted easily and quickly. Communication failures occur owing to changes in the communication environment and collisions. Experimental results demonstrate that the proposed NES-SOURCE’s path-switching function reduces the amount of communication failures when the communication environment changes owing to human movement and others. Furthermore, we clarify the relationships among the probability of a changing communication environment, the collision occurrence rate, and the PER of NES-SOURCE.

  8. 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.

  9. Threshold Switching Induced by Controllable Fragmentation in Silver Nanowire Networks.

    Science.gov (United States)

    Wan, Tao; Pan, Ying; Du, Haiwei; Qu, Bo; Yi, Jiabao; Chu, Dewei

    2018-01-24

    Silver nanowire (Ag NW) networks have been widely studied because of a great potential in various electronic devices. However, nanowires usually undergo a fragmentation process at elevated temperatures due to the Rayleigh instability that is a result of reduction of surface/interface energy. In this case, the nanowires become completely insulating due to the formation of randomly distributed Ag particles with a large distance and further applications are hindered. Herein, we demonstrate a novel concept based on the combination of ultraviolet/ozone irradiation and a low-temperature annealing process to effectively utilize and control the fragmentation behavior to realize the resistive switching performances. In contrast to the conventional fragmentation, the designed Ag/AgO x interface facilitates a unique morphology of short nanorod-like segments or chains of tiny Ag nanoparticles with a very small spacing distance, providing conduction paths for achieving the tunneling process between the isolated fragments under the electric field. On the basis of this specific morphology, the Ag NW network has a tunable resistance and shows volatile threshold switching characteristics with a high selectivity, which is the ON/OFF current ratio in selector devices. Our concept exploits a new function of Ag NW network, i.e., resistive switching, which can be developed by designing a controllable fragmentation.

  10. Novel approach for all-optical packet switching in wide-area networks

    Science.gov (United States)

    Chlamtac, Imrich; Fumagalli, Andrea F.; Wedzinga, Gosse

    1998-09-01

    All-optical Wavelength Division Multiplexing (WDM) networks are believed to be a fundamental component in future high speed backbones. However, while wavelength routing made circuit switching in WDM feasible the reality of extant optical technology does not yet provide the necessary devices to achieve individual optical packet switching. This paper proposes to achieve all-optical packet switching in WDM Wide Area Networks (WANs) via a novel technique, called slot routing. Using slot routing, entire slots, each carrying multiple packets on distinct wavelengths, are switched transparently and individually. As a result packets can be optically transmitted and switched in the network using available fast and wavelength non-sensitive devices. The proposed routing technique leads to an optical packet switching solution, that is simple, practical, and unique as it makes it possible to build a WDM all-optical WAN with optical devices based on proven technologies.

  11. 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

    layers of the network topology. The analysis is based on network-level simulations using a transport network planning tool applied to small-scale setups of the considered DCNs. The obtained results show that introducing all-optical switching within the DCN leads to reduced power consumption in all......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...... an optically switched core benefits most the ring-based network. For the latter, the core ring nodes need fewer long-reach transponders at the trunk interfaces and benefit from more efficient traffic grooming in the access part....

  12. 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.

  13. Optical slotted circuit switched network: a bandwidth efficient alternative to wavelength-routed network

    Science.gov (United States)

    Li, Yan; Collier, Martin

    2007-11-01

    Wavelength-routed networks have received enormous attention due to the fact that they are relatively simple to implement and implicitly offer Quality of Service (QoS) guarantees. However, they suffer from a bandwidth inefficiency problem and require complex Routing and Wavelength Assignment (RWA). Most attempts to address the above issues exploit the joint use of WDM and TDM technologies. The resultant TDM-based wavelength-routed networks partition the wavelength bandwidth into fixed-length time slots organized as a fixed-length frame. Multiple connections can thus time-share a wavelength and the grooming of their traffic leads to better bandwidth utilization. The capability of switching in both wavelength and time domains in such networks also mitigates the RWA problem. However, TMD-based wavelength-routed networks work in synchronous mode and strict synchronization among all network nodes is required. Global synchronization for all-optical networks which operate at extremely high speed is technically challenging, and deploying an optical synchronizer for each wavelength involves considerable cost. An Optical Slotted Circuit Switching (OSCS) architecture is proposed in this paper. In an OSCS network, slotted circuits are created to better utilize the wavelength bandwidth than in classic wavelength-routed networks. The operation of the protocol is such as to avoid the need for global synchronization required by TDM-based wavelength-routed networks.

  14. Quantifying the dynamics of coupled networks of switches and oscillators.

    Directory of Open Access Journals (Sweden)

    Matthew R Francis

    Full Text Available Complex network dynamics have been analyzed with models of systems of coupled switches or systems of coupled oscillators. However, many complex systems are composed of components with diverse dynamics whose interactions drive the system's evolution. We, therefore, introduce a new modeling framework that describes the dynamics of networks composed of both oscillators and switches. Both oscillator synchronization and switch stability are preserved in these heterogeneous, coupled networks. Furthermore, this model recapitulates the qualitative dynamics for the yeast cell cycle consistent with the hypothesized dynamics resulting from decomposition of the regulatory network into dynamic motifs. Introducing feedback into the cell-cycle network induces qualitative dynamics analogous to limitless replicative potential that is a hallmark of cancer. As a result, the proposed model of switch and oscillator coupling provides the ability to incorporate mechanisms that underlie the synchronized stimulus response ubiquitous in biochemical systems.

  15. 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.

  16. Traffic analysis and signal processing in optical packet switched networks

    DEFF Research Database (Denmark)

    Fjelde, Tina

    2002-01-01

    /s optical packet switched network exploiting the best of optics and electronics, is used as a thread throughout the thesis. An overview of the DAVID network architecture is given, focussing on the MAN and WAN architecture as well as the MPLS-based network hierarchy. Subsequently, the traffic performance...... of the DAVID core optical packet router, which exploits wavelength conversion and fibre delay-line buffers for contention resolution, is analysed using a numerical model developed for that purpose. The robustness of the shared recirculating loop buffer with respect to´bursty traffic is demonstrated...... the injection of an additional clock signal into the IWC is presented. Results show very good transmission capabilities combined with a high-speed response. It is argued that signal regeneration is an inherent attribute of the IWC employed as a wavelength converter due to the sinusoidal transfer function...

  17. 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...

  18. An absorptive single-pole four-throw switch using multiple-contact MEMS switches and its application to a monolithic millimeter-wave beam-forming network

    International Nuclear Information System (INIS)

    Lee, Sanghyo; Kim, Jong-Man; Kim, Yong-Kweon; Kwon, Youngwoo

    2009-01-01

    In this paper, a new absorptive single-pole four-throw (SP4T) switch based on multiple-contact switching is proposed and integrated with a Butler matrix to demonstrate a monolithic beam-forming network at millimeter waves (mm waves). In order to simplify the switching driving circuit and reduce the number of unit switches in an absorptive SP4T switch, the individual switches were replaced with long-span multiple-contact switches using stress-free single-crystalline-silicon MEMS technology. This approach improves the mechanical stability as well as the manufacturing yield, thereby allowing successful integration into a monolithic beam former. The fabricated absorptive SP4T MEMS switch shows insertion loss less than 1.3 dB, return losses better than 11 dB at 30 GHz and wideband isolation performance higher than 39 dB from 20 to 40 GHz. The absorptive SP4T MEMS switch is integrated with a 4 × 4 Butler matrix on a single chip to implement a monolithic beam-forming network, directing beam into four distinct angles. Array factors from the measured data show that the proposed absorptive SPnT MEMS switch can be effectively used for high-performance mm-wave beam-switching systems. This work corresponds to the first demonstration of a monolithic beam-forming network using switched beams

  19. Switching dynamics of TaOx-based threshold switching devices

    Science.gov (United States)

    Goodwill, Jonathan M.; Gala, Darshil K.; Bain, James A.; Skowronski, Marek

    2018-03-01

    Bi-stable volatile switching devices are being used as access devices in solid-state memory arrays and as the active part of compact oscillators. Such structures exhibit two stable states of resistance and switch between them at a critical value of voltage or current. A typical resistance transient under a constant amplitude voltage pulse starts with a slow decrease followed by a rapid drop and leveling off at a low steady state value. This behavior prompted the interpretation of initial delay and fast transition as due to two different processes. Here, we show that the entire transient including incubation time, transition time, and the final resistance values in TaOx-based switching can be explained by one process, namely, Joule heating with the rapid transition due to the thermal runaway. The time, which is required for the device in the conducting state to relax back to the stable high resistance one, is also consistent with the proposed mechanism.

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

    NARCIS (Netherlands)

    Calabretta, N.; Miao, W.; Dorren, H.J.S.; Schroder, H.; Chen, R.T.

    2016-01-01

    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

  1. Optical switches based on surface plasmons

    International Nuclear Information System (INIS)

    Chen Cong; Wang Pei; Yuan Guanghui; Wang Xiaolei; Min Changjun; Deng Yan; Lu Yonghua; Ming Hai

    2008-01-01

    Great attention is being paid to surface plasmons (SPs) because of their potential applications in sensors, data storage and bio-photonics. Recently, more and more optical switches based on surface plasmon effects have been demonstrated either by simulation or experimentally. This article describes the principles, advantages and disadvantages of various types of optical switches based on SPs, in particular the all-optical switches. (authors)

  2. Performance of highly connected photonic switching lossless metro-access optical networks

    Science.gov (United States)

    Martins, Indayara Bertoldi; Martins, Yara; Barbosa, Felipe Rudge

    2018-03-01

    The present work analyzes the performance of photonic switching networks, optical packet switching (OPS) and optical burst switching (OBS), in mesh topology of different sizes and configurations. The "lossless" photonic switching node is based on a semiconductor optical amplifier, demonstrated and validated with experimental results on optical power gain, noise figure, and spectral range. The network performance was evaluated through computer simulations based on parameters such as average number of hops, optical packet loss fraction, and optical transport delay (Am). The combination of these elements leads to a consistent account of performance, in terms of network traffic and packet delivery for OPS and OBS metropolitan networks. Results show that a combination of highly connected mesh topologies having an ingress e-buffer present high efficiency and throughput, with very low packet loss and low latency, ensuring fast data delivery to the final receiver.

  3. The Robustness of Stochastic Switching Networks

    OpenAIRE

    Loh, Po-Ling; Zhou, Hongchao; Bruck, Jehoshua

    2009-01-01

    Many natural systems, including chemical and biological systems, can be modeled using stochastic switching circuits. These circuits consist of stochastic switches, called pswitches, which operate with a fixed probability of being open or closed. We study the effect caused by introducing an error of size ∈ to each pswitch in a stochastic circuit. We analyze two constructions – simple series-parallel and general series-parallel circuits – and prove that simple series-parallel circuits are robus...

  4. Carbon nanotube network-silicon oxide non-volatile switches.

    Science.gov (United States)

    Liao, Albert D; Araujo, Paulo T; Xu, Runjie; Dresselhaus, Mildred S

    2014-12-08

    The integration of carbon nanotubes with silicon is important for their incorporation into next-generation nano-electronics. Here we demonstrate a non-volatile switch that utilizes carbon nanotube networks to electrically contact a conductive nanocrystal silicon filament in silicon dioxide. We form this device by biasing a nanotube network until it physically breaks in vacuum, creating the conductive silicon filament connected across a small nano-gap. From Raman spectroscopy, we observe coalescence of nanotubes during breakdown, which stabilizes the system to form very small gaps in the network~15 nm. We report that carbon nanotubes themselves are involved in switching the device to a high resistive state. Calculations reveal that this switching event occurs at ~600 °C, the temperature associated with the oxidation of nanotubes. Therefore, we propose that, in switching to a resistive state, the nanotube oxidizes by extracting oxygen from the substrate.

  5. Supporting differentiated quality of service in optical burst switched networks

    Science.gov (United States)

    Zhou, Bin; Bassiouni, Mostafa A.

    2006-01-01

    We propose and evaluate two new schemes for providing differentiated services in optical burst switched (OBS) networks. The two new schemes are suitable for implementation in OBS networks using just-in-time (JIT) or just-enough-time (JET) scheduling protocols. The first scheme adjusts the size of the search space for a free wavelength based on the priority level of the burst. A simple equation is used to divide the search spectrum into two parts: a base part and an adjustable part. The size of the adjustable part increases as the priority of the burst becomes higher. The scheme is very easy to implement and does not demand any major software or hardware resources in optical cross-connects. The second scheme reduces the dropping probability of bursts with higher priorities through the use of different proactive discarding rates in the network access station (NAS) of the source node. Our extensive simulation tests using JIT show that both schemes are capable of providing tangible quality of service (QoS) differentiation without negatively impacting the throughput of OBS networks.

  6. 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...

  7. Synchronization in slowly switching networks of coupled oscillators

    Science.gov (United States)

    Zhou, Jie; Zou, Yong; Guan, Shuguang; Liu, Zonghua; Boccaletti, S.

    2016-01-01

    Networks whose structure of connections evolves in time constitute a big challenge in the study of synchronization, in particular when the time scales for the evolution of the graph topology are comparable with (or even longer than) those pertinent to the units’ dynamics. We here focus on networks with a slow-switching structure, and show that the necessary conditions for synchronization, i.e. the conditions for which synchronization is locally stable, are determined by the time average of the largest Lyapunov exponents of transverse modes of the switching topologies. Comparison between fast- and slow-switching networks allows elucidating that slow-switching processes prompt synchronization in the cases where the Master Stability Function is concave, whereas fast-switching schemes facilitate synchronization for convex curves. Moreover, the condition of slow-switching enables the introduction of a control strategy for inducing synchronization in networks with arbitrary structure and coupling strength, which is of evident relevance for broad applications in real world systems. PMID:27779253

  8. Self-Management of Hybrid Optical and Packet Switching Networks

    NARCIS (Netherlands)

    Fioreze, Tiago; Pras, Aiko

    Hybrid optical and packet switching networks enable data to be forwarded at multiple levels. Large IP flows at the IP level may be therefore moved to the optical level bypassing the per hop routing decisions of the IP level. Such move could be beneficial since congested IP networks could be

  9. 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.

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

    Science.gov (United States)

    Li, Rui; Hong, Yiguang; Wang, Xingyuan

    2018-04-01

    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.

  11. Cloud networking understanding cloud-based data center networks

    CERN Document Server

    Lee, Gary

    2014-01-01

    Cloud Networking: Understanding Cloud-Based Data Center Networks explains the evolution of established networking technologies into distributed, cloud-based networks. Starting with an overview of cloud technologies, the book explains how cloud data center networks leverage distributed systems for network virtualization, storage networking, and software-defined networking. The author offers insider perspective to key components that make a cloud network possible such as switch fabric technology and data center networking standards. The final chapters look ahead to developments in architectures

  12. A cross-stacked plasmonic nanowire network for high-contrast femtosecond optical switching.

    Science.gov (United States)

    Lin, Yuanhai; Zhang, Xinping; Fang, Xiaohui; Liang, Shuyan

    2016-01-21

    We report an ultrafast optical switching device constructed by stacking two layers of gold nanowires into a perpendicularly crossed network, which works at a speed faster than 280 fs with an on/off modulation depth of about 22.4%. The two stacks play different roles in enhancing consistently the optical switching performance due to their different dependence on the polarization of optical electric fields. The cross-plasmon resonance based on the interaction between the perpendicularly stacked gold nanowires and its Fano-coupling with Rayleigh anomaly is the dominant mechanism for such a high-contrast optical switching device.

  13. Self-Management of Hybrid Optical and Packet Switching Networks

    NARCIS (Netherlands)

    Fioreze, Tiago

    2010-01-01

    Hybrid optical and packet switching networks are composed of multi-service hybrid devices that enable forwarding of data at multiple levels. Large IP flows at the IP level may be therefore moved to the optical level bypassing therefore the per hop routing decisions of the IP level. Such move could

  14. Switching performance of OBS network model under prefetched real traffic

    Science.gov (United States)

    Huang, Zhenhua; Xu, Du; Lei, Wen

    2005-11-01

    Optical Burst Switching (OBS) [1] is now widely considered as an efficient switching technique in building the next generation optical Internet .So it's very important to precisely evaluate the performance of the OBS network model. The performance of the OBS network model is variable in different condition, but the most important thing is that how it works under real traffic load. In the traditional simulation models, uniform traffics are usually generated by simulation software to imitate the data source of the edge node in the OBS network model, and through which the performance of the OBS network is evaluated. Unfortunately, without being simulated by real traffic, the traditional simulation models have several problems and their results are doubtable. To deal with this problem, we present a new simulation model for analysis and performance evaluation of the OBS network, which uses prefetched IP traffic to be data source of the OBS network model. The prefetched IP traffic can be considered as real IP source of the OBS edge node and the OBS network model has the same clock rate with a real OBS system. So it's easy to conclude that this model is closer to the real OBS system than the traditional ones. The simulation results also indicate that this model is more accurate to evaluate the performance of the OBS network system and the results of this model are closer to the actual situation.

  15. 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.

  16. Optimal Switch Configuration in Software-Defined Networks

    Directory of Open Access Journals (Sweden)

    Béla GENGE

    2016-06-01

    Full Text Available The emerging Software-Defined Networks (SDN paradigm facilitates innovative applications and enables the seamless provisioning of resilient communications. Nevertheless, the installation of communication flows in SDN requires careful planning in order to avoid configuration errors and to fulfill communication requirements. In this paper we propose an approach that installs automatically and optimally static flows in SDN switches. The approach aims to select high capacity links and shortest path routing, and enforces communication link and switch capacity limitations. Experimental results demonstrate the effectiveness and scalability of the developed methodology.

  17. Switched-Observer-Based Adaptive Neural Control of MIMO Switched Nonlinear Systems With Unknown Control Gains.

    Science.gov (United States)

    Long, Lijun; Zhao, Jun

    2017-07-01

    In this paper, the problem of adaptive neural output-feedback control is addressed for a class of multi-input multioutput (MIMO) switched uncertain nonlinear systems with unknown control gains. Neural networks (NNs) are used to approximate unknown nonlinear functions. In order to avoid the conservativeness caused by adoption of a common observer for all subsystems, an MIMO NN switched observer is designed to estimate unmeasurable states. A new switched observer-based adaptive neural control technique for the problem studied is then provided by exploiting the classical average dwell time (ADT) method and the backstepping method and the Nussbaum gain technique. It effectively handles the obstacle about the coexistence of multiple Nussbaum-type function terms, and improves the classical ADT method, since the exponential decline property of Lyapunov functions for individual subsystems is no longer satisfied. It is shown that the technique proposed is able to guarantee semiglobal uniformly ultimately boundedness of all the signals in the closed-loop system under a class of switching signals with ADT, and the tracking errors converge to a small neighborhood of the origin. The effectiveness of the approach proposed is illustrated by its application to a two inverted pendulum system.

  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. 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.

  20. 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.

  1. 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

  2. Arduino Based RFID Line Switching Using SSR

    Directory of Open Access Journals (Sweden)

    Michael E.

    2017-10-01

    Full Text Available The importance of line switching cannot be overemphasized as they are used to connect and disconnect substations to and from a distribution grid. At the cradle of technology line switching was achieved via the use of manual switches or fuses which could endanger life as a result of electrocution when expose during maintenance. This ill prompted the development of automated line switching using relays and contactors. With time this tends to fail as a result of wearing of the contact which is as a result of arcing and low voltage. To avert all these ills this paper presents Arduino based Radio Frequency Identification RFID line switching using Solid State Relay SSR. This is to ensure the safety of operators or technologist and to also avert the problem associated with relays and contactors using SSR. This was achieved using RFID RC-522 reader ardriuno Uno SSR and other discrete components. The system was tested and worked perfectly reducing the risk of electrocution and eliminating damage wearing of the contacts common with contactors and relays.

  3. A nanoplasmonic switch based on molecular machines

    KAUST Repository

    Zheng, Yue Bing

    2009-06-01

    We aim to develop a molecular-machine-driven nanoplasmonic switch for its use in future nanophotonic integrated circuits (ICs) that have applications in optical communication, information processing, biological and chemical sensing. Experimental data show that an Au nanodisk array, coated with rotaxane molecular machines, switches its localized surface plasmon resonances (LSPR) reversibly when it is exposed to chemical oxidants and reductants. Conversely, bare Au nanodisks and disks coated with mechanically inert control compounds, do not display the same switching behavior. Along with calculations based on time-dependent density functional theory (TDDFT), these observations suggest that the nanoscale movements within surface-bound "molecular machines" can be used as the active components in plasmonic devices. ©2009 IEEE.

  4. High-speed packet switching network to link computers

    CERN Document Server

    Gerard, F M

    1980-01-01

    Virtually all of the experiments conducted at CERN use minicomputers today; some simply acquire data and store results on magnetic tape while others actually control experiments and help to process the resulting data. Currently there are more than two hundred minicomputers being used in the laboratory. In order to provide the minicomputer users with access to facilities available on mainframes and also to provide intercommunication between various experimental minicomputers, CERN opted for a packet switching network back in 1975. It was decided to use Modcomp II computers as switching nodes. The only software to be taken was a communications-oriented operating system called Maxcom. Today eight Modcomp II 16-bit computers plus six newer Classic minicomputers from Modular Computer Services have been purchased for the CERNET data communications networks. The current configuration comprises 11 nodes connecting more than 40 user machines to one another and to the laboratory's central computing facility. (0 refs).

  5. Power requirements reducing of FBG based all-optical switching

    Science.gov (United States)

    Scholtz, Ľubomír.; Solanská, Michaela; Ladányi, Libor; Müllerová, Jarmila

    2017-12-01

    Although Fiber Bragg gratings (FBGs) are well known devices, their using as all-optical switching elements has been still examined. Current research is focused on optimization of their properties for their using in future all-optical networks. The main problem are high switching intensities needed for achieving the changes of the transmission state. Over several years switching intensities have been reduced from hundreds of GW/cm2 to tens of MW/cm2 by selecting appropriate gratings and signal parameters or using suitable materials. Two principal nonlinear effects with similar power requirements can result in the bistable transmission/reflection of an input optical pulse. In the self-phase modulation (SPM) regime switching is achieved by the intense probe pulse itself. Using cross-phase modulation (XPM) a strong pump alters the FBG refractive index experienced by a weak probe pulse. As a result of this the detuning of the probe pulse from the center of the photonic band gap occurs. Using of XPM the effect of modulation instability is reduced. Modulation instability which is the main SPM degradation mechanism. We focused on nonlinear FBGs based on chalcogenide glasses which are very often used in various applications. Thanks to high nonlinear parameters chalcogenide glasses are suitable candidates for reducing switching intensities of nonlinear FBGs.

  6. Using Alloy to Formally Model and Reason About an OpenFlow Network Switch

    OpenAIRE

    Mirzaei, Saber; Bahargam, Sanaz; Skowyra, Richard; Kfoury, Assaf; Bestavros, Azer

    2016-01-01

    Openflow provides a standard interface for separating a network into a data plane and a programmatic control plane. This enables easy network reconfiguration, but introduces the potential for programming bugs to cause network effects. To study OpenFlow switch behavior, we used Alloy to create a software abstraction describing the internal state of a network and its OpenFlow switches. This work is an attempt to model the static and dynamic behaviour a network built using OpenFlow switches.

  7. Experience with PACS in an ATM/Ethernet switched network environment.

    Science.gov (United States)

    Pelikan, E; Ganser, A; Kotter, E; Schrader, U; Timmermann, U

    1998-03-01

    Legacy local area network (LAN) technologies based on shared media concepts are not adequate for the growth of a large-scale picture archiving and communication system (PACS) in a client-server architecture. First, an asymmetric network load, due to the requests of a large number of PACS clients for only a few main servers, should be compensated by communication links to the servers with a higher bandwidth compared to the clients. Secondly, as the number of PACS nodes increases, the network throughout should not measurably cut production. These requirements can easily be fulfilled using switching technologies. Here asynchronous transfer mode (ATM) is clearly one of the hottest topics in networking because the ATM architecture provides integrated support for a variety of communication services, and it supports virtual networking. On the other hand, most of the imaging modalities are not yet ready for integration into a native ATM network. For a lot of nodes already joining an Ethernet, a cost-effective and pragmatic way to benefit from the switching concept would be a combined ATM/Ethernet switching environment. This incorporates an incremental migration strategy with the immediate benefits of high-speed, high-capacity ATM (for servers and high-sophisticated display workstations), while preserving elements of the existing network technologies. In addition, Ethernet switching instead of shared media Ethernet improves the performance considerably. The LAN emulation (LANE) specification by the ATM forum defines mechanisms that allow ATM networks to coexist with legacy systems using any data networking protocol. This paper points out the suitability of this network architecture in accordance with an appropriate system design.

  8. Performance Test of Openflow Agent on Openflow Software-Based Mikrotik RB750 Switch

    Directory of Open Access Journals (Sweden)

    Rikie Kartadie

    2016-11-01

    Full Text Available A network is usually developed by several devices such as router, switch etc. Every device forwards data package manipulation with complicated protocol planted in its hardware. An operator is responsible for running configuration either to manage rules or application applied in the network. Human error may occur when device configuration run manually by operator. Some famous vendors, one of them is MikroTik, has also been implementing this OpenFlow on its operation. It provides the implementation of SDN/OpenFlow architecture with affordable cost. The second phase research result showed that switch OF software-based MikroTik resulted higher latency value than both mininet and switch OF software-based OpenWRT. The average gap value of switch OF software-based MikroTik is 2012 kbps lower than the value of switch OF software-based OpenWRT. The average gap value of throughput bandwidth protocol UDP switch OF software-based MikroTik is 3.6176 kBps lower than switch OF software-based OpenWRT and it is 8.68 kBps lower than mininet. The average gap throughput jitter protokol UDP of switch OF software-based MiktoTik is 0.0103ms lower than switch OF software-based OpenWRT and 0.0093ms lower than mininet. 

  9. Switching dynamics in reaction networks induced by molecular discreteness

    International Nuclear Information System (INIS)

    Togashi, Yuichi; Kaneko, Kunihiko

    2007-01-01

    To study the fluctuations and dynamics in chemical reaction processes, stochastic differential equations based on the rate equation involving chemical concentrations are often adopted. When the number of molecules is very small, however, the discreteness in the number of molecules cannot be neglected since the number of molecules must be an integer. This discreteness can be important in biochemical reactions, where the total number of molecules is not significantly larger than the number of chemical species. To elucidate the effects of such discreteness, we study autocatalytic reaction systems comprising several chemical species through stochastic particle simulations. The generation of novel states is observed; it is caused by the extinction of some molecular species due to the discreteness in their number. We demonstrate that the reaction dynamics are switched by a single molecule, which leads to the reconstruction of the acting network structure. We also show the strong dependence of the chemical concentrations on the system size, which is caused by transitions to discreteness-induced novel states

  10. Controllability of switched singular mix-valued logical control networks with constraints

    Science.gov (United States)

    Deng, Lei; Gong, Mengmeng; Zhu, Peiyong

    2018-03-01

    The present paper investigates the controllability problem of switched singular mix-valued logical control networks (SSMLCNs) with constraints on states and controls. First, using the semi-tenser product (STP) of matrices, the SSMLCN is expressed in an algebraic form, based on which a necessary and sufficient condition is given for the uniqueness of solution of SSMLCNs. Second, a necessary and sufficient criteria is derived for the controllability of constrained SSMLCNs, by converting a constrained SSMLCN into a parallel constrained switched mix-valued logical control network. Third, an algorithm is presented to design a proper switching sequence and a control scheme which force a state to a reachable state. Finally, a numerical example is given to demonstrate the efficiency of the results obtained in this paper.

  11. A theoretical and experimental study of neuromorphic atomic switch networks for reservoir computing.

    Science.gov (United States)

    Sillin, Henry O; Aguilera, Renato; Shieh, Hsien-Hang; Avizienis, Audrius V; Aono, Masakazu; Stieg, Adam Z; Gimzewski, James K

    2013-09-27

    Atomic switch networks (ASNs) have been shown to generate network level dynamics that resemble those observed in biological neural networks. To facilitate understanding and control of these behaviors, we developed a numerical model based on the synapse-like properties of individual atomic switches and the random nature of the network wiring. We validated the model against various experimental results highlighting the possibility to functionalize the network plasticity and the differences between an atomic switch in isolation and its behaviors in a network. The effects of changing connectivity density on the nonlinear dynamics were examined as characterized by higher harmonic generation in response to AC inputs. To demonstrate their utility for computation, we subjected the simulated network to training within the framework of reservoir computing and showed initial evidence of the ASN acting as a reservoir which may be optimized for specific tasks by adjusting the input gain. The work presented represents steps in a unified approach to experimentation and theory of complex systems to make ASNs a uniquely scalable platform for neuromorphic computing.

  12. 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...

  13. 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.

  14. Optical switching systems using nanostructures

    DEFF Research Database (Denmark)

    Stubkjær, Kristian

    2004-01-01

    High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems.......High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems....

  15. 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.

  16. Exponentially convergent state estimation for delayed switched recurrent neural networks.

    Science.gov (United States)

    Ahn, Choon Ki

    2011-11-01

    This paper deals with the delay-dependent exponentially convergent state estimation problem for delayed switched neural networks. A set of delay-dependent criteria is derived under which the resulting estimation error system is exponentially stable. It is shown that the gain matrix of the proposed state estimator is characterised in terms of the solution to a set of linear matrix inequalities (LMIs), which can be checked readily by using some standard numerical packages. An illustrative example is given to demonstrate the effectiveness of the proposed state estimator.

  17. Path searching in switching networks using cellular algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Koczy, L T; Langer, J; Legendi, T

    1981-01-01

    After a survey of the important statements in the paper A Mathematical Model of Path Searching in General Type Switching Networks (see IBID., vol.25, no.1, p.31-43, 1981) the authors consider the possible implementation for cellular automata of the algorithm introduced there. The cellular field used consists of 5 neighbour 8 state cells. Running times required by a traditional serial processor and by the cellular field, respectively, are compared. By parallel processing this running time can be reduced. 5 references.

  18. Global Asymptotic Stability of Switched Neural Networks with Delays

    Directory of Open Access Journals (Sweden)

    Zhenyu Lu

    2015-01-01

    Full Text Available This paper investigates the global asymptotic stability of a class of switched neural networks with delays. Several new criteria ensuring global asymptotic stability in terms of linear matrix inequalities (LMIs are obtained via Lyapunov-Krasovskii functional. And here, we adopt the quadratic convex approach, which is different from the linear and reciprocal convex combinations that are extensively used in recent literature. In addition, the proposed results here are very easy to be verified and complemented. Finally, a numerical example is provided to illustrate the effectiveness of the results.

  19. Leo satellite-based telecommunication network concepts

    Science.gov (United States)

    Aiken, John G.; Swan, Peter A.; Leopold, Ray J.

    1991-01-01

    Design considerations are discussed for Low Earth Orbit (LEO) satellite based telecommunications networks. The satellites are assumed to be connected to each other via intersatellite links. They are connected to the end user either directly or through gateways to other networks. Frequency reuse, circuit switching, packet switching, call handoff, and routing for these systems are discussed by analogy with terrestrial cellular (mobile radio) telecommunication systems.

  20. Constructing large scale SCI-based processing systems by switch elements

    International Nuclear Information System (INIS)

    Wu, B.; Kristiansen, E.; Skaali, B.; Bogaerts, A.; Divia, R.; Mueller, H.

    1993-05-01

    The goal of this paper is to study some of the design criteria for the switch elements to form the interconnection of large scale SCI-based processing systems. The approved IEEE standard 1596 makes it possible to couple up to 64K nodes together. In order to connect thousands of nodes to construct large scale SCI-based processing systems, one has to interconnect these nodes by switch elements to form different topologies. A summary of the requirements and key points of interconnection networks and switches is presented. Two models of the SCI switch elements are proposed. The authors investigate several examples of systems constructed for 4-switches with simulations and the results are analyzed. Some issues and enhancements are discussed to provide the ideas behind the switch design that can improve performance and reduce latency. 29 refs., 11 figs., 3 tabs

  1. Task-set switching under cue-based versus memory-based switching conditions in younger and older adults.

    Science.gov (United States)

    Kray, Jutta

    2006-08-11

    Adult age differences in task switching and advance preparation were examined by comparing cue-based and memory-based switching conditions. Task switching was assessed by determining two types of costs that occur at the general (mixing costs) and specific (switching costs) level of switching. Advance preparation was investigated by varying the time interval until the next task (short, middle, very long). Results indicated that the implementation of task sets was different for cue-based switching with random task sequences and memory-based switching with predictable task sequences. Switching costs were strongly reduced under cue-based switching conditions, indicating that task-set cues facilitate the retrieval of the next task. Age differences were found for mixing costs and for switching costs only under cue-based conditions in which older adults showed smaller switching costs than younger adults. It is suggested that older adults adopt a less extreme bias between two tasks than younger adults in situations associated with uncertainty. For cue-based switching with random task sequences, older adults are less engaged in a complete reconfiguration of task sets because of the probability of a further task change. Furthermore, the reduction of switching costs was more pronounced for cue- than memory-based switching for short preparation intervals, whereas the reduction of switch costs was more pronounced for memory- than cue-based switching for longer preparation intervals at least for older adults. Together these findings suggest that the implementation of task sets is functionally different for the two types of task-switching conditions.

  2. Ultra High-Speed Radio Frequency Switch Based on Photonics.

    Science.gov (United States)

    Ge, Jia; Fok, Mable P

    2015-11-26

    Microwave switches, or Radio Frequency (RF) switches have been intensively used in microwave systems for signal routing. Compared with the fast development of microwave and wireless systems, RF switches have been underdeveloped particularly in terms of switching speed and operating bandwidth. In this paper, we propose a photonics based RF switch that is capable of switching at tens of picoseconds speed, which is hundreds of times faster than any existing RF switch technologies. The high-speed switching property is achieved with the use of a rapidly tunable microwave photonic filter with tens of gigahertz frequency tuning speed, where the tuning mechanism is based on the ultra-fast electro-optics Pockels effect. The RF switch has a wide operation bandwidth of 12 GHz and can go up to 40 GHz, depending on the bandwidth of the modulator used in the scheme. The proposed RF switch can either work as an ON/OFF switch or a two-channel switch, tens of picoseconds switching speed is experimentally observed for both type of switches.

  3. 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

  4. Finite-time consensus for leader-following multi-agent systems over switching network topologies

    International Nuclear Information System (INIS)

    Sun Feng-Lan; Zhu Wei

    2013-01-01

    Finite-time consensus problem of the leader-following multi-agent system under switching network topologies is studied in this paper. Based on the graph theory, matrix theory, homogeneity with dilation, and LaSalle's invariance principle, the control protocol of each agent using local information is designed, and the detailed analysis of the leader-following finite-time consensus is provided. Some examples and simulation results are given to illustrate the effectiveness of the obtained theoretical results

  5. Energy efficient SDN commodity switch based practical flow forwarding method

    KAUST Repository

    Alghadhban, Amer Mohammad JarAlla; Shihada, Basem

    2016-01-01

    -table size and the number of control messages. Consequently, the power consumption of network switches is in orders of magnitude less than other evaluated solutions. It also provides flow management flexibility and scalability. We compare EncPath with single

  6. 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).

  7. Shape-Memory Hydrogels: Evolution of Structural Principles To Enable Shape Switching of Hydrophilic Polymer Networks.

    Science.gov (United States)

    Löwenberg, Candy; Balk, Maria; Wischke, Christian; Behl, Marc; Lendlein, Andreas

    2017-04-18

    The ability of hydrophilic chain segments in polymer networks to strongly interact with water allows the volumetric expansion of the material and formation of a hydrogel. When polymer chain segments undergo reversible hydration depending on environmental conditions, smart hydrogels can be realized, which are able to shrink/swell and thus alter their volume on demand. In contrast, implementing the capacity of hydrogels to switch their shape rather than volume demands more sophisticated chemical approaches and structural concepts. In this Account, the principles of hydrogel network design, incorporation of molecular switches, and hydrogel microstructures are summarized that enable a spatially directed actuation of hydrogels by a shape-memory effect (SME) without major volume alteration. The SME involves an elastic deformation (programming) of samples, which are temporarily fixed by reversible covalent or physical cross-links resulting in a temporary shape. The material can reverse to the original shape when these molecular switches are affected by application of a suitable stimulus. Hydrophobic shape-memory polymers (SMPs), which are established with complex functions including multiple or reversible shape-switching, may provide inspiration for the molecular architecture of shape-memory hydrogels (SMHs), but cannot be identically copied in the world of hydrophilic soft materials. For instance, fixation of the temporary shape requires cross-links to be formed also in an aqueous environment, which may not be realized, for example, by crystalline domains from the hydrophilic main chains as these may dissolve in presence of water. Accordingly, dual-shape hydrogels have evolved, where, for example, hydrophobic crystallizable side chains have been linked into hydrophilic polymer networks to act as temperature-sensitive temporary cross-links. By incorporating a second type of such side chains, triple-shape hydrogels can be realized. Considering the typically given light

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

    KAUST Repository

    Rached, Nadhir B.; Ghazzai, Hakim; Kadri, Abdullah; Alouini, Mohamed-Slim

    2018-01-01

    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.

  9. 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.

  10. 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.

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

    KAUST Repository

    Haskovec, Jan

    2014-01-01

    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

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

    KAUST Repository

    Shihada, Basem; Zhang, Qiong; Ho, Pin-Han; Jue, Jason P.

    2010-01-01

    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

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

    KAUST Repository

    Shihada, Basem; El-Ferik, Sami; Ho, Pin-Han

    2013-01-01

    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

  14. Performance evaluation of a high-speed switched network for PACS

    Science.gov (United States)

    Zhang, Randy H.; Tao, Wenchao; Huang, Lu J.; Valentino, Daniel J.

    1998-07-01

    We have replaced our shared-media Ethernet and FDDI network with a multi-tiered, switched network using OC-12 (622 Mbps) ATM for the network backbone, OC3 (155 Mbps) connections to high-end servers and display workstations, and switched 100/10 Mbps Ethernet for workstations and desktop computers. The purpose of this research was to help PACS designers and implementers understand key performance factors in a high- speed switched network by characterizing and evaluating its image delivery performance, specifically, the performance of socket-based TCP (Transmission Control Protocol) and DICOM 3.0 communications. A test network within the UCLA Clinical RIS/PACS was constructed using Sun UltraSPARC-II machines with ATM, Fast Ethernet, and Ethernet network interfaces. To identify performance bottlenecks, we evaluated network throughput for memory to memory, memory to disk, disk to memory, and disk to disk transfers. To evaluate the effect of file size, tests involving disks were further divided using sizes of small (514 KB), medium (8 MB), and large (16 MB) files. The observed maximum throughput for various network configurations using the TCP protocol was 117 Mbps for memory to memory and 88 MBPS for memory to disk. For disk to memory, the peak throughput was 98 Mbps using small files, 114 Mbps using medium files, and 116 Mbps using large files. The peak throughput for disk to disk became 64 Mbps using small files and 96 Mbps using medium and large files. The peak throughput using the DICOM 3.0 protocol was substantially lower in all categories. The measured throughput varied significantly among the tests when TCP socket buffer was raised above the default value. The optimal buffer size was approximately 16 KB or the TCP protocol and around 256 KB for the DICOM protocol. The application message size also displayed distinctive effects on network throughput when the TCP socket buffer size was varied. The throughput results for Fast Ethernet and Ethernet were expectedly

  15. 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.

  16. Wireless Nanoionic-Based Radio Frequency Switch

    Science.gov (United States)

    Nessel, James A. (Inventor); Miranda, Felix A (Inventor)

    2017-01-01

    A nanoionic switch connected to one or more rectenna modules is disclosed. The rectenna module is configured to receive a wireless signal and apply a first bias to change a state of the nanoionic switch from a first state to a second state. The rectenna module can receive a second wireless signal and apply a second bias to change the nanoionic switch from the second state back to the first state. The first bias is generally opposite of the first bias. The rectenna module accordingly permits operation of the nanoionic switch without onboard power.

  17. Mobile based Appliances switching using Bluetooth

    Science.gov (United States)

    Gupta, Sureshchandra J., Dr; Desai, Kalp; Gaikawad, Deepak; Pawar, Vijay N.; Gangal, Devendranath R.

    2008-04-01

    How many times do you have to get up from your desk to switch on your Air conditioner or fan when you are completely into your table work? How many times do you feel lazy to get off your comfort to switch on/off your home appliances in different rooms? How much energy do you lose in a day for operating your appliances? The solution is either a large amount of manual work—or the idea that is presented over here: APP-CON (APP-CON stands for appliances control). Here the ordinary cell phone with bluetooth capability acts as remote designed in such a manner that it acts as a helping hand to human by reducing its manual work and therefore saving human energy. The cell phone control of APP-CON units lets you access many of your home appliances situated in different rooms by using just a single remote from distance. Electronics hobbyists would love to make such a remote control themselves. But they find it difficult due to complex circuitry rather than the high cost because of using a number of frequency counting techniques and decade counters. The APP-CON system given here overcomes the aforesaid problems by using a single microcontroller and moreover a simple program or software for bluetooth enabled cell phone and employing simple coding and decoding of remote signals. Here the mobile based remote control is used to operate a number of home appliances basically consists of Bluetooth technology. The unit consists of a transmitter and a receiver consisting of a microcontroller. The importance of bluetooth technology is that the signal to be transmitted from transmitter to the receiver is done without requiring line of sight.

  18. 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.

  19. A nanoplasmonic switch based on molecular machines

    KAUST Repository

    Zheng, Yue Bing; Yang, Ying-Wei; Jensen, Lasse; Fang, Lei; Juluri, Bala Krishna; Weiss, Paul S.; Stoddart, J. Fraser; Huang, Tony Jun

    2009-01-01

    We aim to develop a molecular-machine-driven nanoplasmonic switch for its use in future nanophotonic integrated circuits (ICs) that have applications in optical communication, information processing, biological and chemical sensing. Experimental

  20. 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.

  1. First Field Trial of Optical Label-Based Switching and Packet Drop on a 477km NTON/Sprint Link

    International Nuclear Information System (INIS)

    Hernandez, V J; Pan, Z; Cao, J; Tsui, V K; Bansal, Y; Fong, S K H; Zhang, Y; Jeon, M Y; Yoo, S J B; Bodtker, B; Bond, S; Lennon, W J; Higashi, H; Lyles, B; McDonald, R

    2001-01-01

    We demonstrate the first field trial of optical label-based wavelength switching and packet drop on 476.8km of the National Transparent Optical Network. Subcarrier multiplexed labels control a switch fabric that includes a tunable wavelength converter and arrayed waveguide grating router

  2. Programs for control of an analog-signal switching network

    International Nuclear Information System (INIS)

    D'Ottavio, T.; Enriquez, R.; Katz, R.; Skelly, J.

    1989-01-01

    A suite of programs has been developed to control the network of analog-signal switching multiplexers in the AGS complex. The software is driven by a relational database which describes the architecture of the multiplexer tree and the set of available analog signals. Signals are routed through a three-layer multiplexer tree, to be made available at four consoles each with three 4-trace oscilloscopes. A menu-structured operator interface program is available at each console, to accept requests to route any available analog signal to any of that console's 12 oscilloscope traces. A common routing-server program provides automatic routing-server program provides automatic routing of requested signals through the layers of multiplexers, maintaining a reservation database to denote free and in-use trunks. Expansion of the analog signal system is easily accommodated in software by adding new signals, trunks, multiplexers, or consoles to the database. Programmatic control of the triggering signals for each of the oscilloscopes is also provided. 3 refs., 4 figs., 3 tabs

  3. Dimensioning of 10 Gbit/s all-optical packet switched networks based on optical label swapping routers with multistage 2R regeneration.

    Science.gov (United States)

    Puerto, G; Ortega, B; Manzanedo, M D; Martínez, A; Pastor, D; Capmany, J; Kovacs, G

    2006-10-30

    This paper describes both the experimental and theoretical investigations on the cascadability of all-optical routers in optical label swapping networks incorporating a multistage wavelength conversion with 2R regeneration. A full description of a novel experimental setup allows the packet by packet measurement up to 16 hops with 10 Gb/s payload showing 1 dB penalty with 10(-12) bit error rate. Similarly, the simulations on the system allow a prediction on the cascadability of the router up to 64 hops.

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

    Energy Technology Data Exchange (ETDEWEB)

    El-Sharkawi, Mohamed A. (Renton, WA); Andexler, George (Everett, WA); Silberkleit, Lee I. (Mountlake Terrace, WA)

    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).

  6. Hybrid Spectral Unmixing: Using Artificial Neural Networks for Linear/Non-Linear Switching

    Directory of Open Access Journals (Sweden)

    Asmau M. Ahmed

    2017-07-01

    Full Text Available Spectral unmixing is a key process in identifying spectral signature of materials and quantifying their spatial distribution over an image. The linear model is expected to provide acceptable results when two assumptions are satisfied: (1 The mixing process should occur at macroscopic level and (2 Photons must interact with single material before reaching the sensor. However, these assumptions do not always hold and more complex nonlinear models are required. This study proposes a new hybrid method for switching between linear and nonlinear spectral unmixing of hyperspectral data based on artificial neural networks. The neural networks was trained with parameters within a window of the pixel under consideration. These parameters are computed to represent the diversity of the neighboring pixels and are based on the Spectral Angular Distance, Covariance and a non linearity parameter. The endmembers were extracted using Vertex Component Analysis while the abundances were estimated using the method identified by the neural networks (Vertex Component Analysis, Fully Constraint Least Square Method, Polynomial Post Nonlinear Mixing Model or Generalized Bilinear Model. Results show that the hybrid method performs better than each of the individual techniques with high overall accuracy, while the abundance estimation error is significantly lower than that obtained using the individual methods. Experiments on both synthetic dataset and real hyperspectral images demonstrated that the proposed hybrid switch method is efficient for solving spectral unmixing of hyperspectral images as compared to individual algorithms.

  7. A miniaturized reconfigurable broadband attenuator based on RF MEMS switches

    International Nuclear Information System (INIS)

    Guo, Xin; Gong, Zhuhao; Zhong, Qi; Liang, Xiaotong; Liu, Zewen

    2016-01-01

    Reconfigurable attenuators are widely used in microwave measurement instruments. Development of miniaturized attenuation devices with high precision and broadband performance is required for state-of-the-art applications. In this paper, a compact 3-bit microwave attenuator based on radio frequency micro-electro-mechanical system (RF MEMS) switches and polysilicon attenuation modules is presented. The device comprises 12 ohmic contact MEMS switches, π -type polysilicon resistive attenuation modules and microwave compensate structures. Special attention was paid to the design of the resistive network, compensate structures and system simulation. The device was fabricated using micromachining processes compatible with traditional integrated circuit fabrication processes. The reconfigurable attenuator integrated with RF MEMS switches and resistive attenuation modules was successfully fabricated with dimensions of 2.45  ×  4.34  ×  0.5 mm 3 , which is 1/1000th of the size of a conventional step attenuator. The measured RF performance revealed that the attenuator provides 10–70 dB attenuation at 10 dB intervals from 0.1–20 GHz with an accuracy better than  ±1.88 dB at 60 dB and an error of less than 2.22 dB at 10 dB. The return loss of each state of the 3-bit attenuator was better than 11.95 dB (VSWR  <  1.71) over the entire operating band. (paper)

  8. 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.

  9. Method to optimize optical switch topology for photonic network-on-chip

    Science.gov (United States)

    Zhou, Ting; Jia, Hao

    2018-04-01

    In this paper, we propose a method to optimize the optical switch by substituting optical waveguide crossings for optical switching units and an optimizing algorithm to complete the optimization automatically. The functionality of the optical switch remains constant under optimization. With this method, we simplify the topology of optical switch, which means the insertion loss and power consumption of the whole optical switch can be effectively minimized. Simulation result shows that the number of switching units of the optical switch based on Spanke-Benes can be reduced by 16.7%, 20%, 20%, 19% and 17.9% for the scale from 4 × 4 to 8 × 8 respectively. As a proof of concept, the experimental demonstration of an optimized six-port optical switch based on Spanke-Benes structure by means of silicon photonics chip is reported.

  10. Co-ordination and Lock-in: Competition with Switching Costs and Network Effects

    OpenAIRE

    Joseph Farrell; Paul Klemperer

    2006-01-01

    Switching costs and network effects bind customers to vendors if products are incompatible, locking customers or even markets in to early choices. Lock-in hinders customers from changing suppliers in response to (predictable or unpredictable) changes in effciency, and gives vendors lucrative ex post market power-over the same buyer in the case of switching costs (or brand loyalty), or over others with network effects. Firms compete ex ante for this ex post power, using penetration pricing, in...

  11. Coordination and Lock-In: Competition with Switching Costs and Network Effects

    OpenAIRE

    Farrell, Joseph; Klemperer, Paul

    2006-01-01

    Switching costs and network effects bind customers to vendors if products are incompatible, locking customers or even markets in to early choices. Lock-in hinders customers from changing suppliers in response to (predictable or unpredictable) changes in efficiency, and gives vendors lucrative ex post market power—over the same buyer in the case of switching costs (or brand loyalty), or over others with network effects. Firms compete ex ante for this ex post power, using penetration ...

  12. Modelling switching-time effects in high-frequency power conditioning networks

    Science.gov (United States)

    Owen, H. A.; Sloane, T. H.; Rimer, B. H.; Wilson, T. G.

    1979-01-01

    Power transistor networks which switch large currents in highly inductive environments are beginning to find application in the hundred kilohertz switching frequency range. Recent developments in the fabrication of metal-oxide-semiconductor field-effect transistors in the power device category have enhanced the movement toward higher switching frequencies. Models for switching devices and of the circuits in which they are imbedded are required to properly characterize the mechanisms responsible for turning on and turning off effects. Easily interpreted results in the form of oscilloscope-like plots assist in understanding the effects of parametric studies using topology oriented computer-aided analysis methods.

  13. 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

    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.......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...

  14. A nonlinear plasmonic waveguide based all-optical bidirectional switching

    Science.gov (United States)

    Bana, Xiaoqiang; Pang, Xingxing; Li, Xiaohui; Hu, Bin; Guo, Yixuan; Zheng, Hairong

    2018-01-01

    In this paper, an all-optical switching with a nanometer coupled ring resonator is demonstrated based on the nonlinear material. By adjusting the light intensity, we implement the resonance wavelength from 880 nm to 940 nm in the nonlinear material structure monocyclic. In the bidirectional switch structure, the center wavelength (i.e. 880 nm) is fixed. By changing the light intensity from I = 0 to I = 53 . 1 MW /cm2, the function of optical switching can be obtained. The results demonstrate that both the single-ring cavity and the T-shaped double-ring structure can realize the optical switching effect. This work takes advantage of the simple structure. The single-ring cavity plasmonic switches have many advantages, such as nanoscale size, low pumping light intensity, ultrafast response time (femtosecond level), etc. It is expected that the proposed all-optical integrated devices can be potentially applied in optical communication, signal processing, and signal sensing, etc.

  15. A Microcontroller-Based Automatic Transfer Switching System for a ...

    African Journals Online (AJOL)

    Michael

    2015-06-01

    Jun 1, 2015 ... Most industries still employ the manual method of power supply changeover, ... This paper presents a Microcontroller-Based Automatic Transfer Switching System ..... and currently has special research interest in Wireless.

  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 addition, we propose a novel synchronization algorithm that enables automatic synchronization of software defined networking controlled all-optical TDM switching nodes connected in a ring network. Besides providing synchronization, the algorithm also can facilitate dynamic slot size change and failure......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...... detection. We experimentally validate the algorithm behavior and achieve correct operation for three different ring lengths. Moreover, we experimentally demonstrate data plane connectivity in a ring network composed of three nodes and show successful wavelength division multiplexing space division...

  17. Scalable Active Optical Access Network Using Variable High-Speed PLZT Optical Switch/Splitter

    Science.gov (United States)

    Ashizawa, Kunitaka; Sato, Takehiro; Tokuhashi, Kazumasa; Ishii, Daisuke; Okamoto, Satoru; Yamanaka, Naoaki; Oki, Eiji

    This paper proposes a scalable active optical access network using high-speed Plumbum Lanthanum Zirconate Titanate (PLZT) optical switch/splitter. The Active Optical Network, called ActiON, using PLZT switching technology has been presented to increase the number of subscribers and the maximum transmission distance, compared to the Passive Optical Network (PON). ActiON supports the multicast slot allocation realized by running the PLZT switch elements in the splitter mode, which forces the switch to behave as an optical splitter. However, the previous ActiON creates a tradeoff between the network scalability and the power loss experienced by the optical signal to each user. It does not use the optical power efficiently because the optical power is simply divided into 0.5 to 0.5 without considering transmission distance from OLT to each ONU. The proposed network adopts PLZT switch elements in the variable splitter mode, which controls the split ratio of the optical power considering the transmission distance from OLT to each ONU, in addition to PLZT switch elements in existing two modes, the switching mode and the splitter mode. The proposed network introduces the flexible multicast slot allocation according to the transmission distance from OLT to each user and the number of required users using three modes, while keeping the advantages of ActiON, which are to support scalable and secure access services. Numerical results show that the proposed network dramatically reduces the required number of slots and supports high bandwidth efficiency services and extends the coverage of access network, compared to the previous ActiON, and the required computation time for selecting multicast users is less than 30msec, which is acceptable for on-demand broadcast services.

  18. Flexible optical network components based on densely integrated microring resonators

    NARCIS (Netherlands)

    Geuzebroek, D.H.

    2005-01-01

    This thesis addresses the design, realization and characterization of reconfigurable optical network components based on multiple microring resonators. Since thermally tunable microring resonators can be used as wavelength selective space switches, very compact devices with high complexity and

  19. Results from a data acquisition system prototype project using a switch-based event builder

    International Nuclear Information System (INIS)

    Black, D.; Andresen, J.; Barsotti, E.; Baumbaugh, A.; Esterline, D.; Knickerbocker, K.; Kwarciany, R.; Moore, G.; Patrick, J.; Swoboda, C.; Treptow, K.; Trevizo, O.; Urish, J.; VanConant, R.; Walsh, D.; Bowden, M.; Booth, A.; Cancelo, G.

    1991-11-01

    A prototype of a high bandwidth parallel event builder has been designed and tested. The architecture is based on a simple switching network and is adaptable to a wide variety of data acquisition systems. An eight channel system with a peak throughput of 160 Megabytes per second has been implemented. It is modularly expandable to 64 channels (over one Gigabyte per second). The prototype uses a number of relatively recent commercial technologies, including very high speed fiber-optic data links, high integration crossbar switches and embedded RISC processors. It is based on an open architecture which permits the installation of new technologies with little redesign effort. 5 refs., 6 figs

  20. Results from a data acquisition system prototype project using a switch-based event builder

    Energy Technology Data Exchange (ETDEWEB)

    Black, D.; Andresen, J.; Barsotti, E.; Baumbaugh, A.; Esterline, D.; Knickerbocker, K.; Kwarciany, R.; Moore, G.; Patrick, J.; Swoboda, C.; Treptow, K.; Trevizo, O.; Urish, J.; VanConant, R.; Walsh, D. (Fermi National Accelerator Lab., Batavia, IL (United States)); Bowden, M.; Booth, A. (Superconducting Super Collider Lab., Dallas, TX (United States)); Cancelo, G. (La Plata Univ. Nacional (Argentina))

    1991-11-01

    A prototype of a high bandwidth parallel event builder has been designed and tested. The architecture is based on a simple switching network and is adaptable to a wide variety of data acquisition systems. An eight channel system with a peak throughput of 160 Megabytes per second has been implemented. It is modularly expandable to 64 channels (over one Gigabyte per second). The prototype uses a number of relatively recent commercial technologies, including very high speed fiber-optic data links, high integration crossbar switches and embedded RISC processors. It is based on an open architecture which permits the installation of new technologies with little redesign effort. 5 refs., 6 figs.

  1. High-power semiconductor RSD-based switch

    Energy Technology Data Exchange (ETDEWEB)

    Bezuglov, V G; Galakhov, I V; Grusin, I A [All-Russian Scientific Research Inst. of Experimental Physics, Sarov (Russian Federation); and others

    1997-12-31

    The operating principle and test results of a high-power semiconductor RSD-based switch with the following operating parameters is described: operating voltage 25 kV, peak operating current 200 kA, maximum transferred charge 70 C. The switch is intended for use by high-power capacitor banks of state-of-the-art research facilities. The switch was evaluated for applicability in commercial pulsed systems. The possibility of increasing the peak operating current to 500 kA is demonstrated. (author). 4 figs., 2 refs.

  2. Chemical switches and logic gates based on surface modified semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Konrad, Szacilowski; Wojciech, Macyk [Jagiellonian Univ., Dept. of Chemistry, Krakow (Poland)

    2006-02-15

    Photoelectrochemical properties of multicomponent photo-electrodes based on titanium dioxide and cadmium sulfide powders modified with hexacyanoferrate complexes have been examined. Photocurrent responses were recorded as functions of applied potential and photon energy. Surprisingly, the photocurrent can be switched between positive and negative values as a result of potential or photon energy changes. This new effect called Photo Electrochemical Photocurrent Switching (PEPS) opens a possibility of new chemical switches and logic gates construction. Boolean logic analysis and a tentative mechanism of the device are discussed. (authors)

  3. High-efficiency thermal switch based on topological Josephson junctions

    Science.gov (United States)

    Sothmann, Björn; Giazotto, Francesco; Hankiewicz, Ewelina M.

    2017-02-01

    We propose theoretically a thermal switch operating by the magnetic-flux controlled diffraction of phase-coherent heat currents in a thermally biased Josephson junction based on a two-dimensional topological insulator. For short junctions, the system shows a sharp switching behavior while for long junctions the switching is smooth. Physically, the switching arises from the Doppler shift of the superconducting condensate due to screening currents induced by a magnetic flux. We suggest a possible experimental realization that exhibits a relative temperature change of 40% between the on and off state for realistic parameters. This is a factor of two larger than in recently realized thermal modulators based on conventional superconducting tunnel junctions.

  4. 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...

  5. A packet-switched network for data readout from the LHC inner detector

    International Nuclear Information System (INIS)

    Ostby, J.M.; Sorasen, O.

    1994-01-01

    This paper presents a network which can be used for data fusion in the planned LHC (Large Hadron Collider) ATLAS experiment at CERN. The network named SWIPP (SWitched Interconnection of Parallel Processors), is built of 16 x 16 star switches and protocol engines connected by pairs of optical fibers. Each channel is designed to carry up to 1 Gbps in each direction. The paper will give a brief introduction to SWIPP principles and ASIC implementation. Some of the advantages offered by the network will be mentioned

  6. Observer-Based Robust Control of Uncertain Switched Fuzzy Systems with Combined Switching Controller

    Directory of Open Access Journals (Sweden)

    Hong Yang

    2013-01-01

    Full Text Available The observer-based robust control for a class of switched fuzzy (SF time-delay systems involving uncertainties and external disturbances is investigated in this paper. A switched fuzzy system, which differs from existing ones, is firstly employed to describe a nonlinear system. Next, a combined switching controller is proposed. The designed controller based on the observer instead of the state information integrates the advantages of both the switching controllers and the supplementary controllers but eliminates their disadvantages. The proposed controller provides good performance during the transient period, and the chattering effect is removed when the system state approaches the origin. Sufficient condition for the solvability of the robust control problem is given for the case that the state of system is not available. Since convex combination techniques are used to derive the delay-independent criteria, some subsystems are allowed to be unstable. Finally, various comparisons of the elaborated examples are conducted to demonstrate the effectiveness of the proposed control design approach.

  7. Switch/router architectures shared-bus and shared-memory based systems

    CERN Document Server

    Aweya, James

    2018-01-01

    A practicing engineer's inclusive review of communication systems based on shared-bus and shared-memory switch/router architectures. This book delves into the inner workings of router and switch design in a comprehensive manner that is accessible to a broad audience. It begins by describing the role of switch/routers in a network, then moves on to the functional composition of a switch/router. A comparison of centralized versus distributed design of the architecture is also presented. The author discusses use of bus versus shared-memory for communication within a design, and also covers Quality of Service (QoS) mechanisms and configuration tools. Written in a simple style and language to allow readers to easily understand and appreciate the material presented, Switch/Router Architectures: Shared-Bus and Shared-Memory Based Systems discusses the design of multilayer switches—starting with the basic concepts and on to the basic architectures. It describes the evolution of multilayer switch designs and highli...

  8. Network-Based Effectiveness

    National Research Council Canada - National Science Library

    Friman, Henrik

    2006-01-01

    ...) to increase competitive advantage, innovation, and mission effectiveness. Network-based effectiveness occurs due to the influence of various factors such as people, procedures, technology, and organizations...

  9. 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

  10. Path Diversity Media Streaming over Best Effort Packet Switched Networks

    Science.gov (United States)

    2003-01-01

    intolerable sounds of my violin practice, but my mom was always there to defend and encourage her young violinist. When I left my full-time job for graduate...information can be incomplete or inaccurate. For exam - ple, traceroute can only differentiate between routers and not switches. Two paths with completely

  11. Studi Migrasi Public Switched Telephone Network (Pstn) Menuju Jaringan Telekomunikasi Berbasis Paket Next Generation Network (Ngn) Dengan Teknologi Softswitch

    OpenAIRE

    Suseno, Andrias Danang; Najib, Warsun; Samiyono, -

    2009-01-01

    Public Switched Telephone Network (PSTN) adalah sistem telekomunikasi berbasis circuit-switched. Pada awalnya PSTN hanya menyediakan layanan voice. PSTN sekarang telah berkembang ke arah pelayanan komunikasi data yang didorong oleh berkembangnya dunia internet dengan Internet Protokol (IP)-nya. Telah muncul teknologi Voice over IP (VoIP) yang mampu melewatkan trafik voice pada jaringan data dengan mengubah voice menjadi paket. VoIP telah mendorong trend/kecenderungan terjadinya konvergensi an...

  12. Six-port optical switch for cluster-mesh photonic network-on-chip

    Science.gov (United States)

    Jia, Hao; Zhou, Ting; Zhao, Yunchou; Xia, Yuhao; Dai, Jincheng; Zhang, Lei; Ding, Jianfeng; Fu, Xin; Yang, Lin

    2018-05-01

    Photonic network-on-chip for high-performance multi-core processors has attracted substantial interest in recent years as it offers a systematic method to meet the demand of large bandwidth, low latency and low power dissipation. In this paper we demonstrate a non-blocking six-port optical switch for cluster-mesh photonic network-on-chip. The architecture is constructed by substituting three optical switching units of typical Spanke-Benes network to optical waveguide crossings. Compared with Spanke-Benes network, the number of optical switching units is reduced by 20%, while the connectivity of routing path is maintained. By this way the footprint and power consumption can be reduced at the expense of sacrificing the network latency performance in some cases. The device is realized by 12 thermally tuned silicon Mach-Zehnder optical switching units. Its theoretical spectral responses are evaluated by establishing a numerical model. The experimental spectral responses are also characterized, which indicates that the optical signal-to-noise ratios of the optical switch are larger than 13.5 dB in the wavelength range from 1525 nm to 1565 nm. Data transmission experiment with the data rate of 32 Gbps is implemented for each optical link.

  13. Switching auditory attention using spatial and non-spatial features recruits different cortical networks.

    Science.gov (United States)

    Larson, Eric; Lee, Adrian K C

    2014-01-01

    Switching attention between different stimuli of interest based on particular task demands is important in many everyday settings. In audition in particular, switching attention between different speakers of interest that are talking concurrently is often necessary for effective communication. Recently, it has been shown by multiple studies that auditory selective attention suppresses the representation of unwanted streams in auditory cortical areas in favor of the target stream of interest. However, the neural processing that guides this selective attention process is not well understood. Here we investigated the cortical mechanisms involved in switching attention based on two different types of auditory features. By combining magneto- and electro-encephalography (M-EEG) with an anatomical MRI constraint, we examined the cortical dynamics involved in switching auditory attention based on either spatial or pitch features. We designed a paradigm where listeners were cued in the beginning of each trial to switch or maintain attention halfway through the presentation of concurrent target and masker streams. By allowing listeners time to switch during a gap in the continuous target and masker stimuli, we were able to isolate the mechanisms involved in endogenous, top-down attention switching. Our results show a double dissociation between the involvement of right temporoparietal junction (RTPJ) and the left inferior parietal supramarginal part (LIPSP) in tasks requiring listeners to switch attention based on space and pitch features, respectively, suggesting that switching attention based on these features involves at least partially separate processes or behavioral strategies. © 2013 Elsevier Inc. All rights reserved.

  14. 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.

  15. Software defined networks reactive flow programming and load balance switching

    OpenAIRE

    Καλλιανιώτης, Νικόλαος; Kallianiotis, Nikolaos

    2017-01-01

    This project serves as a Master Thesis as the requirements of the master’s programme Master of Digital Communications and Networks. It proposes load balancing algorithms applied to Software-Defined Networks to achieve the best possible resource utilisation of each of the links present in a network. The open-sources Opendaylight project and Floodlight project are used as SDN controllers, and the network is emulated using Mininet software

  16. Adaptive approach to global synchronization of directed networks with fast switching topologies

    International Nuclear Information System (INIS)

    Qin Buzhi; Lu Xinbiao

    2010-01-01

    Global synchronization of directed networks with switching topologies is investigated. It is found that if there exists at least one directed spanning tree in the network with the fixed time-average topology and the time-average topology is achieved sufficiently fast, the network will reach global synchronization for appreciate coupling strength. Furthermore, this appreciate coupling strength may be obtained by local adaptive approach. A sufficient condition about the global synchronization is given. Numerical simulations verify the effectiveness of the adaptive strategy.

  17. 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.

  18. 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.

  19. 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

  20. Default mode network abnormalities during state switching in attention deficit hyperactivity disorder.

    Science.gov (United States)

    Sidlauskaite, J; Sonuga-Barke, E; Roeyers, H; Wiersema, J R

    2016-02-01

    Individuals with attention deficit hyperactivity disorder (ADHD) display excess levels of default mode network (DMN) activity during goal-directed tasks, which are associated with attentional disturbances and performance decrements. One hypothesis is that this is due to attenuated down-regulation of this network during rest-to-task switching. A second related hypothesis is that it may be associated with right anterior insula (rAI) dysfunction - a region thought to control the actual state-switching process. These hypotheses were tested in the current fMRI study in which 19 adults with ADHD and 21 typically developing controls undertook a novel state-to-state switching paradigm. Advance cues signalled upcoming switches between rest and task periods and switch-related anticipatory modulation of DMN and rAI was measured. To examine whether rest-to-task switching impairments may be a specific example of a more general state regulation deficit, activity upon task-to-rest cues was also analysed. Against our hypotheses, we found that the process of down-regulating the DMN when preparing to switch from rest to task was unimpaired in ADHD and that there was no switch-specific deficit in rAI modulation. However, individuals with ADHD showed difficulties up-regulating the DMN when switching from task to rest. Rest-to-task DMN attenuation seems to be intact in adults with ADHD and thus appears unrelated to excess DMN activity observed during tasks. Instead, individuals with ADHD exhibit attenuated up-regulation of the DMN, hence suggesting disturbed re-initiation of a rest state.

  1. Controlled perturbation-induced switching in pulse-coupled oscillator networks

    International Nuclear Information System (INIS)

    Schittler Neves, Fabio; Timme, Marc

    2009-01-01

    Pulse-coupled systems such as spiking neural networks exhibit nontrivial invariant sets in the form of attracting yet unstable saddle periodic orbits where units are synchronized into groups. Heteroclinic connections between such orbits may in principle support switching processes in these networks and enable novel kinds of neural computations. For small networks of coupled oscillators, we here investigate under which conditions and how system symmetry enforces or forbids certain switching transitions that may be induced by perturbations. For networks of five oscillators, we derive explicit transition rules that for two cluster symmetries deviate from those known from oscillators coupled continuously in time. A third symmetry yields heteroclinic networks that consist of sets of all unstable attractors with that symmetry and the connections between them. Our results indicate that pulse-coupled systems can reliably generate well-defined sets of complex spatiotemporal patterns that conform to specific transition rules. We briefly discuss possible implications for computation with spiking neural systems.

  2. Controlled perturbation-induced switching in pulse-coupled oscillator networks

    Energy Technology Data Exchange (ETDEWEB)

    Schittler Neves, Fabio; Timme, Marc [Network Dynamics Group, Max Planck Institute for Dynamics and Self-Organization, Goettingen, D-37073 (Germany); Bernstein Center for Computational Neuroscience (BCCN), Goettingen (Germany)], E-mail: neves@nld.ds.mpg.de, E-mail: timme@nld.ds.mpg.de

    2009-08-28

    Pulse-coupled systems such as spiking neural networks exhibit nontrivial invariant sets in the form of attracting yet unstable saddle periodic orbits where units are synchronized into groups. Heteroclinic connections between such orbits may in principle support switching processes in these networks and enable novel kinds of neural computations. For small networks of coupled oscillators, we here investigate under which conditions and how system symmetry enforces or forbids certain switching transitions that may be induced by perturbations. For networks of five oscillators, we derive explicit transition rules that for two cluster symmetries deviate from those known from oscillators coupled continuously in time. A third symmetry yields heteroclinic networks that consist of sets of all unstable attractors with that symmetry and the connections between them. Our results indicate that pulse-coupled systems can reliably generate well-defined sets of complex spatiotemporal patterns that conform to specific transition rules. We briefly discuss possible implications for computation with spiking neural systems.

  3. 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".

  4. Synchronization transmission of laser pattern signal within uncertain switched network

    Science.gov (United States)

    Lü, Ling; Li, Chengren; Li, Gang; Sun, Ao; Yan, Zhe; Rong, Tingting; Gao, Yan

    2017-06-01

    We propose a new technology for synchronization transmission of laser pattern signal within uncertain network with controllable topology. In synchronization process, the connection of dynamic network can vary at all time according to different demands. Especially, we construct the Lyapunov function of network through designing a special semi-positive definite function, and the synchronization transmission of laser pattern signal within uncertain network with controllable topology can be realized perfectly, which effectively avoids the complicated calculation for solving the second largest eignvalue of the coupling matrix of the dynamic network in order to obtain the network synchronization condition. At the same time, the uncertain parameters in dynamic equations belonging to network nodes can also be identified accurately via designing the identification laws of uncertain parameters. In addition, there are not any limitations for the synchronization target of network in the new technology, in other words, the target can either be a state variable signal of an arbitrary node within the network or an exterior signal.

  5. Optimizing POF/PCF based optical switch for indoor LAN

    International Nuclear Information System (INIS)

    Bhuiyan, M M I; Rashid, M M; Ahmed, Sayem; Bhuiyan, M; Kajihara, M

    2013-01-01

    For indoor local area network (LAN) the Polymer optical fiber (POF) is mostly appropriate, because of its large core diameter and flexible material. A 1×2 optical switch for indoor LAN using POF and a shape memory alloy (SMA) coil actuator with magnetic latches was successfully fabricated and tested. To achieve switching by the movement of a POF, large displacement is necessary because the core diameter is large (e.g., 0.486mm). A SMA coil actuator is used for large displacement and a magnetic latching system is used for fixing the position of the shifted POF. The insertion loss is 0.40 to 0.50dB and crosstalk is more than 50dB without index-matching oil. Switching speed is less than 1s at a driving current of 80mA. A cycling test was performed 1.4 million times. Polymer clad fiber optical (PCF) switch also fabricated and tasted

  6. Generalized Switched-Inductor Based Buck-Boost Z-H Converter

    Directory of Open Access Journals (Sweden)

    E. Babaei

    2017-12-01

    Full Text Available In this paper, a generalized buck-boost Z-H converter based on switched inductors is proposed. This structure consists of a set of series connected switched-inductor cells. The voltage conversion ratio of the proposed structure is adjusted by changing the number of cells and the duty cycle. Like the conventional Z-H converter, the shoot-through switching state and the diode before LC network are eliminated. The proposed converter can provide high voltage gain in low duty cycles. Considering different values for duty cycle, the proposed structure works in two operating zones. In the first operating zone, it works as a buck-boost converter and in the second operating zone, it works as a boost converter. In this paper, a complete analysis of the proposed converter is presented. In order to confirm the accuracy of mathematic calculations, the simulations results by using PSCAD/EMTDC software are given.

  7. Fast oscillations in cortical-striatal networks switch frequency following rewarding events and stimulant drugs.

    Science.gov (United States)

    Berke, J D

    2009-09-01

    Oscillations may organize communication between components of large-scale brain networks. Although gamma-band oscillations have been repeatedly observed in cortical-basal ganglia circuits, their functional roles are not yet clear. Here I show that, in behaving rats, distinct frequencies of ventral striatal local field potential oscillations show coherence with different cortical inputs. The approximately 50 Hz gamma oscillations that normally predominate in awake ventral striatum are coherent with piriform cortex, whereas approximately 80-100 Hz high-gamma oscillations are coherent with frontal cortex. Within striatum, entrainment to gamma rhythms is selective to fast-spiking interneurons, with distinct fast-spiking interneuron populations entrained to different gamma frequencies. Administration of the psychomotor stimulant amphetamine or the dopamine agonist apomorphine causes a prolonged decrease in approximately 50 Hz power and increase in approximately 80-100 Hz power. The same frequency switch is observed for shorter epochs spontaneously in awake, undrugged animals and is consistently provoked for reward receipt. Individual striatal neurons can participate in these brief high-gamma bursts with, or without, substantial changes in firing rate. Switching between discrete oscillatory states may allow different modes of information processing during decision-making and reinforcement-based learning, and may also be an important systems-level process by which stimulant drugs affect cognition and behavior.

  8. NM-Net Gigabit-based Implementation on Core Network Facilities and Network Design Hierarchy

    International Nuclear Information System (INIS)

    Raja Murzaferi Raja Moktar; Mohd Fauzi Haris; Siti Nurbahyah Hamdan

    2011-01-01

    Nuclear Malaysia computing network or NM the main backbone of internet working on operational staffs. Main network operating center or NOC is situated in Block 15 and linkup via fiber cabling to adjacent main network blocks (18, 29, 11 connections. Pre 2009 infrastructure; together to form the core networking switch. of the core network infrastructure were limited by the up link between core switches that is the Pair (UTP) Category 6 Cable. Furthermore, majority of the networking infrastructure throughout the agency were mainly built with Fast Ethernet Based specifications to date. With current research and operational tasks highly dependent on IT infrastructure that is being enabled through NM-Net, the performance NM-Net implementing gigabit-based networking system achieve optimal performance of internet networking services in the agency thus catalyze initiative. (author)

  9. Evolutionary prisoner's dilemma games on the network with punishment and opportunistic partner switching

    Science.gov (United States)

    Takesue, H.

    2018-02-01

    Punishment and partner switching are two well-studied mechanisms that support the evolution of cooperation. Observation of human behaviour suggests that the extent to which punishment is adopted depends on the usage of alternative mechanisms, including partner switching. In this study, we investigate the combined effect of punishment and partner switching in evolutionary prisoner's dilemma games conducted on a network. In the model, agents are located on the network and participate in the prisoner's dilemma games with punishment. In addition, they can opportunistically switch interaction partners to improve their payoff. Our Monte Carlo simulation showed that a large frequency of punishers is required to suppress defectors when the frequency of partner switching is low. In contrast, cooperation is the most abundant strategy when the frequency of partner switching is high regardless of the strength of punishment. Interestingly, cooperators become abundant not because they avoid the cost of inflicting punishment and earn a larger average payoff per game but rather because they have more numerous opportunities to be referred to as a role agent by defectors. Our results imply that the fluidity of social relationships has a profound effect on the adopted strategy in maintaining cooperation.

  10. Atomic switch networks-nanoarchitectonic design of a complex system for natural computing.

    Science.gov (United States)

    Demis, E C; Aguilera, R; Sillin, H O; Scharnhorst, K; Sandouk, E J; Aono, M; Stieg, A Z; Gimzewski, J K

    2015-05-22

    Self-organized complex systems are ubiquitous in nature, and the structural complexity of these natural systems can be used as a model to design new classes of functional nanotechnology based on highly interconnected networks of interacting units. Conventional fabrication methods for electronic computing devices are subject to known scaling limits, confining the diversity of possible architectures. This work explores methods of fabricating a self-organized complex device known as an atomic switch network and discusses its potential utility in computing. Through a merger of top-down and bottom-up techniques guided by mathematical and nanoarchitectonic design principles, we have produced functional devices comprising nanoscale elements whose intrinsic nonlinear dynamics and memorization capabilities produce robust patterns of distributed activity and a capacity for nonlinear transformation of input signals when configured in the appropriate network architecture. Their operational characteristics represent a unique potential for hardware implementation of natural computation, specifically in the area of reservoir computing-a burgeoning field that investigates the computational aptitude of complex biologically inspired systems.

  11. 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....

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

    KAUST Repository

    Sayed, Mostafa M.; Abdallah, Mohamed M.; Alouini, Mohamed-Slim; Qaraqe, Khalid A.

    2011-01-01

    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.

  14. 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.

  15. CERNET - A high-speed packet-switching network

    International Nuclear Information System (INIS)

    Gerard, J.M.

    1981-01-01

    A general mesh-structured high-speed computer network has been designed and built. This network provides communication between any pair of connected user computers over distances of upto 6 km and at line speeds of 1 to 5 Mbit/second. The network is composed of a communication subnet providing a datagram service, complemented by tasks in the connected machines to implement an end-to-end logical link protocol. Details are given of the overall structure as well as the specific modules of which the system is composed. (orig.)

  16. A Novel Silicon-based Wideband RF Nano Switch Matrix Cell and the Fabrication of RF Nano Switch Structures

    Directory of Open Access Journals (Sweden)

    Yi Xiu YANG

    2011-12-01

    Full Text Available This paper presents the concept of RF nano switch matrix cell and the fabrication of RF nano switch. The nano switch matrix cell can be implemented into complex switch matrix for signal routing. RF nano switch is the decision unit for the matrix cell; in this research, it is fabricated on a tri-layer high-resistivity-silicon substrate using surface micromachining approach. Electron beam lithography is introduced to define the pattern and IC compatible deposition process is used to construct the metal layers. Silicon-based nano switch fabricated by IC compatible process can lead to a high potential of system integration to perform a cost effective system-on-a-chip solution. In this paper, simulation results of the designed matrix cell are presented; followed by the details of the nano structure fabrication and fabrication challenges optimizations; finally, measurements of the fabricated nano structure along with analytical discussions are also discussed.

  17. Enhancement of resistive switching properties in Al2O3 bilayer-based atomic switches: multilevel resistive switching

    Science.gov (United States)

    Vishwanath, Sujaya Kumar; Woo, Hyunsuk; Jeon, Sanghun

    2018-06-01

    Atomic switches are considered to be building blocks for future non-volatile data storage and internet of things. However, obtaining device structures capable of ultrahigh density data storage, high endurance, and long data retention, and more importantly, understanding the switching mechanisms are still a challenge for atomic switches. Here, we achieved improved resistive switching performance in a bilayer structure containing aluminum oxide, with an oxygen-deficient oxide as the top switching layer and stoichiometric oxide as the bottom switching layer, using atomic layer deposition. This bilayer device showed a high on/off ratio (105) with better endurance (∼2000 cycles) and longer data retention (104 s) than single-oxide layers. In addition, depending on the compliance current, the bilayer device could be operated in four different resistance states. Furthermore, the depth profiles of the hourglass-shaped conductive filament of the bilayer device was observed by conductive atomic force microscopy.

  18. Network-Based Effectiveness

    National Research Council Canada - National Science Library

    Friman, Henrik

    2006-01-01

    ... (extended from Leavitt, 1965). This text identifies aspects of network-based effectiveness that can benefit from a better understanding of leadership and management development of people, procedures, technology, and organizations...

  19. Opportunistic spectrum access in cognitive radio based on channel switching

    KAUST Repository

    Gaaloul, Fakhreddine; Yang, Hongchuan; Radaydeh, Redha Mahmoud Mesleh; Alouini, Mohamed-Slim

    2012-01-01

    This paper investigates the performance of a cognitive radio transceiver that can monitor multiple channels and opportunistically use any one of them should it be available. In our work, we propose and compare two different opportunistic channel access schemes. The first scheme applies when the secondary user (SU) has access to only one channel. The second scheme applies when the SU has access to multiple channels but can at a given time monitor and access only one channel. Two switching strategies, namely the switch and examine and the switch and stay strategies, are proposed. For these proposed access schemes, we investigate their performance by deriving the analytical expression of the novel metric of the average access duration and the average waiting time and based on these two metrics a time average SU throughput formula is proposed to predict the performance of the secondary cognitive system. © 2012 ICST.

  20. A fluorescence switch based on a controllable photochromic naphthopyran group

    International Nuclear Information System (INIS)

    Chen Lizhen; Wang Guang; Zhao Xiancai

    2011-01-01

    A fluorescence switch based on photoisomerization of naphthopyran (NP) has been designed by employing 2-(pyridin-2-yl)-benzimidazole (BPI) and the naphthopyran containing two pyran rings (NP) as fluorescent dye and photochromic compound, respectively. The fluorescence switch of benzimidazole derivative can be modulated either by controlling the irradiation time of UV light or by adjusting the amount ratio of fluorescent benzimidazole derivative to photochromic naphthopyran in both solution and polymethyl methacrylate (PMMA) film. The experimental results indicated that the decrease of fluorescence intensity of benzimidazole derivative is attributed to the interaction of benzimidazole with naphthopyran. - Highlights: → Naphthopyran was first used to fabricate fluorescence switch with benzimidazole derivative. → Fluorescence intensity can be modulated by controlling the UV irradiation time. → Fluorescence intensity can be adjusted by changing the ratio of benzimidazole derivative to naphthopyran. → Decrease of fluorescence intensity is attributed to the interaction of benzimidazole derivative and naphthopyran.

  1. Next Generation Campus Network Deployment Project Based on Softswitch

    OpenAIRE

    HU Feng; LIU Ziyan

    2011-01-01

    After analyzing the current networks of Guizhou University,we brought forward a scheme of next generation campus networks based on softswitch technology by choosing SoftX3000 switching system of HuaWei and provided the specific solution of accessing campus networks in this paper. It is proved that this scheme is feasible by using OPNET, which not only accomplished the integration of the PSTN and IP networks but also achieved the combining of voice services and data services.

  2. 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).

  3. 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

  4. Confinement and diffusion modulate bistability and stochastic switching in a reaction network with positive feedback

    International Nuclear Information System (INIS)

    Mlynarczyk, Paul J.; Pullen, Robert H.; Abel, Steven M.

    2016-01-01

    Positive feedback is a common feature in signal transduction networks and can lead to phenomena such as bistability and signal propagation by domain growth. Physical features of the cellular environment, such as spatial confinement and the mobility of proteins, play important but inadequately understood roles in shaping the behavior of signaling networks. Here, we use stochastic, spatially resolved kinetic Monte Carlo simulations to explore a positive feedback network as a function of system size, system shape, and mobility of molecules. We show that these physical properties can markedly alter characteristics of bistability and stochastic switching when compared with well-mixed simulations. Notably, systems of equal volume but different shapes can exhibit qualitatively different behaviors under otherwise identical conditions. We show that stochastic switching to a state maintained by positive feedback occurs by cluster formation and growth. Additionally, the frequency at which switching occurs depends nontrivially on the diffusion coefficient, which can promote or suppress switching relative to the well-mixed limit. Taken together, the results provide a framework for understanding how confinement and protein mobility influence emergent features of the positive feedback network by modulating molecular concentrations, diffusion-influenced rate parameters, and spatiotemporal correlations between molecules

  5. Global Robust Stability of Switched Interval Neural Networks with Discrete and Distributed Time-Varying Delays of Neural Type

    Directory of Open Access Journals (Sweden)

    Huaiqin Wu

    2012-01-01

    Full Text Available By combing the theories of the switched systems and the interval neural networks, the mathematics model of the switched interval neural networks with discrete and distributed time-varying delays of neural type is presented. A set of the interval parameter uncertainty neural networks with discrete and distributed time-varying delays of neural type are used as the individual subsystem, and an arbitrary switching rule is assumed to coordinate the switching between these networks. By applying the augmented Lyapunov-Krasovskii functional approach and linear matrix inequality (LMI techniques, a delay-dependent criterion is achieved to ensure to such switched interval neural networks to be globally asymptotically robustly stable in terms of LMIs. The unknown gain matrix is determined by solving this delay-dependent LMIs. Finally, an illustrative example is given to demonstrate the validity of the theoretical results.

  6. Energy efficient SDN commodity switch based practical flow forwarding method

    KAUST Repository

    AlGhadhban, Amer

    2016-07-04

    Recent SDN researches suffer from over-accumulation of unhealthy flow-load. Instead, we leverage the SDN controller network view to encode the end-to-end path information into the packet address. Our solution EncPath significantly reduces the flow-table size and the number of control messages. Consequently, the power consumption of network switches is in orders of magnitude less than other evaluated solutions. It also provides flow management flexibility and scalability. We compare EncPath with single and multipath routing solutions and single path solution. Also, we operated them in proactive and reactive modes. We find that EncPath flow entries in core switches in a multihomed fat-tree with 144 hosts is approximately 1000 times smaller than Equal-Cost MultiPath (ECMP) and random routing. Additionally, the number of control messages to setup the network is reduced by a factor of 200×. This, consequently, affords data-plane and control-plane devices space to process other tasks. © 2016 IEEE.

  7. High speed switching for computer and communication networks

    NARCIS (Netherlands)

    Dorren, H.J.S.

    2014-01-01

    The role of data centers and computers are vital for the future of our data-centric society. Historically the performance of data-centers is increasing with a factor 100-1000 every ten years and as a result of this the capacity of the data-center communication network has to scale accordingly. This

  8. Burst switched optical networks supporting legacy and future service types

    DEFF Research Database (Denmark)

    Franzl, Gerald; Hayat, Faisal; Holynski, Tomasz

    2011-01-01

    Focusing on the principles and the paradigm of OBS an overview addressing expectable performance and application issues is presented. Proposals on OBS were published over a decade and the presented techniques spread into many directions. The paper comprises discussions of several challenges that ...... and found capable to overcome shortcomings of recent proposals. In conclusion, an OBS that offers different connection types may support most client demands within a sole optical network layer....

  9. Study on spin filtering and switching action in a double-triangular network chain

    Science.gov (United States)

    Zhang, Yongmei

    2018-04-01

    Spin transport properties of a double-triangular quantum network with local magnetic moment on backbones and magnetic flux penetrating the network plane are studied. Numerical simulation results show that such a quantum network will be a good candidate for spin filter and spin switch. Local dispersion and density of states are considered in the framework of tight-binding approximation. Transmission coefficients are calculated by the method of transfer matrix. Spin transmission is regulated by substrate magnetic moment and magnetic flux piercing those triangles. Experimental realization of such theoretical research will be conducive to designing of new spintronic devices.

  10. Software development for a switch-based data acquisition system

    Energy Technology Data Exchange (ETDEWEB)

    Booth, A. (Superconducting Super Collider Lab., Dallas, TX (United States)); Black, D.; Walsh, D. (Fermi National Accelerator Lab., Batavia, IL (United States))

    1991-12-01

    We report on the software aspects of the development of a switch-based data acquisition system at Fermilab. This paper describes how, with the goal of providing an integrated systems engineering'' environment, several powerful software tools were put in place to facilitate extensive exploration of all aspects of the design. These tools include a simulation package, graphics package and an Expert System shell which have been integrated to provide an environment which encourages the close interaction of hardware and software engineers. This paper includes a description of the simulation, user interface, embedded software, remote procedure calls, and diagnostic software which together have enabled us to provide real-time control and monitoring of a working prototype switch-based data acquisition (DAQ) system.

  11. No switch to coal-based feedstocks until 2000

    Energy Technology Data Exchange (ETDEWEB)

    1977-06-10

    This is a resume of a paper ''Organics for the 1980s-petrochemicals or coal chemicals'' by S. P. S. Andrew. There will be no significant switch from petrochemicals to coal-based chemicals worldwide until well into the 21st century, when synthetic gasoline could be made in the U. S. from open-cast coal. Processes are being developed for converting coal to gasoline, ethylene, and ammonia.

  12. Ultrashort soliton switching based on coherent energy hiding.

    Science.gov (United States)

    Romagnoli, M; Wabnitz, S; Zoccolotti, L

    1991-08-15

    Coherent coupling between light and atoms may be exploited for conceiving a novel class of all-optical signalprocessing devices without a direct counterpart in the continuous-wave regime. We show that the self-switching of ultrashort soliton pulses on resonance with a transition of doping centers in a slab waveguide directional coupler is based on nonlinear group-velocity (instead of the usual phase-velocity) changes.

  13. A Complementary Resistive Switch-based Crossbar Array Adder

    OpenAIRE

    Siemon, A.; Menzel, S.; Waser, R.; Linn, E.

    2014-01-01

    Redox-based resistive switching devices (ReRAM) are an emerging class of non-volatile storage elements suited for nanoscale memory applications. In terms of logic operations, ReRAM devices were suggested to be used as programmable interconnects, large-scale look-up tables or for sequential logic operations. However, without additional selector devices these approaches are not suited for use in large scale nanocrossbar memory arrays, which is the preferred architecture for ReRAM devices due to...

  14. Switch Reluctance Motor Control Based on Fuzzy Logic System

    Directory of Open Access Journals (Sweden)

    S. V. Aleksandrovsky

    2012-01-01

    Full Text Available Due to its intrinsic simplicity and reliability, the switched reluctance motor (SRM has now become a promising candidate for variable-speed drive applications as an alternative induction motor in various industrial application. However, the SRM has the disadvantage of nonlinear characteristic and control. It is suggested to use controller based on fuzzy logic system. Design of FLS controller and simulation model presented.

  15. Personal Computer Based Controller For Switched Reluctance Motor Drives

    Science.gov (United States)

    Mang, X.; Krishnan, R.; Adkar, S.; Chandramouli, G.

    1987-10-01

    Th9, switched reluctance motor (SRM) has recently gained considerable attention in the variable speed drive market. Two important factors that have contributed to this are, the simplicity of construction and the possibility of developing low cost con-trollers with minimum number of switching devices in the drive circuits. This is mainly due to the state-of-art of the present digital circuits technology and the low cost of switching devices. The control of this motor drive is under research. Optimized performance of the SRM motor drive is very dependent on the integration of the controller, converter and the motor. This research on system integration involves considerable changes in the control algorithms and their implementation. A Personal computer (PC) based controller is very appropriate for this purpose. Accordingly, the present paper is concerned with the design of a PC based controller for a SRM. The PC allows for real-time microprocessor control with the possibility of on-line system parameter modifications. Software reconfiguration of this controller is easier than a hardware based controller. User friendliness is a natural consequence of such a system. Considering the low cost of PCs, this controller will offer an excellent cost-effective means of studying the control strategies for the SRM drive intop greater detail than in the past.

  16. Potential energy landscape and robustness of a gene regulatory network: toggle switch.

    Directory of Open Access Journals (Sweden)

    Keun-Young Kim

    2007-03-01

    Full Text Available Finding a multidimensional potential landscape is the key for addressing important global issues, such as the robustness of cellular networks. We have uncovered the underlying potential energy landscape of a simple gene regulatory network: a toggle switch. This was realized by explicitly constructing the steady state probability of the gene switch in the protein concentration space in the presence of the intrinsic statistical fluctuations due to the small number of proteins in the cell. We explored the global phase space for the system. We found that the protein synthesis rate and the unbinding rate of proteins to the gene were small relative to the protein degradation rate; the gene switch is monostable with only one stable basin of attraction. When both the protein synthesis rate and the unbinding rate of proteins to the gene are large compared with the protein degradation rate, two global basins of attraction emerge for a toggle switch. These basins correspond to the biologically stable functional states. The potential energy barrier between the two basins determines the time scale of conversion from one to the other. We found as the protein synthesis rate and protein unbinding rate to the gene relative to the protein degradation rate became larger, the potential energy barrier became larger. This also corresponded to systems with less noise or the fluctuations on the protein numbers. It leads to the robustness of the biological basins of the gene switches. The technique used here is general and can be applied to explore the potential energy landscape of the gene networks.

  17. Fault Detection for Wireless Networked Control Systems with Stochastic Switching Topology and Time Delay

    Directory of Open Access Journals (Sweden)

    Pengfei Guo

    2014-01-01

    Full Text Available This paper deals with the fault detection problem for a class of discrete-time wireless networked control systems described by switching topology with uncertainties and disturbances. System states of each individual node are affected not only by its own measurements, but also by other nodes’ measurements according to a certain network topology. As the topology of system can be switched in a stochastic way, we aim to design H∞ fault detection observers for nodes in the dynamic time-delay systems. By using the Lyapunov method and stochastic analysis techniques, sufficient conditions are acquired to guarantee the existence of the filters satisfying the H∞ performance constraint, and observer gains are derived by solving linear matrix inequalities. Finally, an illustrated example is provided to verify the effectiveness of the theoretical results.

  18. Guaranteed cost control of mobile sensor networks with Markov switching topologies.

    Science.gov (United States)

    Zhao, Yuan; Guo, Ge; Ding, Lei

    2015-09-01

    This paper investigates the consensus seeking problem of mobile sensor networks (MSNs) with random switching topologies. The network communication topologies are composed of a set of directed graphs (or digraph) with a spanning tree. The switching of topologies is governed by a Markov chain. The consensus seeking problem is addressed by introducing a global topology-aware linear quadratic (LQ) cost as the performance measure. By state transformation, the consensus problem is transformed to the stabilization of a Markovian jump system with guaranteed cost. A sufficient condition for global mean-square consensus is derived in the context of stochastic stability analysis of Markovian jump systems. A computational algorithm is given to synchronously calculate both the sub-optimal consensus controller gains and the sub-minimum upper bound of the cost. The effectiveness of the proposed design method is illustrated by three numerical examples. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  19. Optical switching in data centers : architectures based on optical packet/burst switching

    NARCIS (Netherlands)

    Calabretta, Nicola; Miao, Wang; Testa, F.; Pavesi, L.

    2017-01-01

    Driven by the cloud computing, Internet of things, and emerging big data applications, more stringent requirements in terms of high bandwidth, low latency, and large interconnectivity are imposed on the communications within the data centers (DC). Traditional intra-DC network based on electronic

  20. A Reduced Switch Voltage Stress Class E Power Amplifier Using Harmonic Control Network

    OpenAIRE

    Ali Reza Zirak; Sobhan Roshani

    2016-01-01

    In this paper, a harmonic control network (HCN) is presented to reduce the voltage stress (maximum MOSFET voltage) of the class E power amplifier (PA). Effects of the HCN on the amplifier specifications are investigated. The results show that the proposed HCN affects several specifications of the amplifier, such as drain voltage, switch current, output power capability (Cp factor), and drain impedance. The output power capability of the presented amplifier is also improved, compared with the ...

  1. THESEUS: A wavelength division multiplexed/microwave subcarrier multiplexed optical network, its ATM switch applications and device requirements

    Science.gov (United States)

    Xin, Wei

    1997-10-01

    A Terabit Hybrid Electro-optical /underline[Se]lf- routing Ultrafast Switch (THESEUS) has been proposed. It is a self-routing wavelength division multiplexed (WDM) / microwave subcarrier multiplexed (SCM) asynchronous transfer mode (ATM) switch for the multirate ATM networks. It has potential to be extended to a large ATM switch as 1000 x 1000 without internal blocking. Among the advantages of the hybrid implementation are flexibility in service upgrade, relaxed tolerances on optical filtering, protocol simplification and less processing overhead. For a small ATM switch, the subcarrier can be used as output buffers to solve output contention. A mathematical analysis was conducted to evaluate different buffer configurations. A testbed has been successfully constructed. Multirate binary data streams have been switched through the testbed and error free reception ([<]10-9 bit error rate) has been achieved. A simple, intuitive theoretical model has been developed to describe the heterodyne optical beat interference. A new concept of interference time and interference length has been introduced. An experimental confirmation has been conducted. The experimental results match the model very well. It shows that a large portion of optical bandwidth is wasted due to the beat interference. Based on the model, several improvement approaches have been proposed. The photo-generated carrier lifetime of silicon germanium has been measured using time-resolved reflectivity measurement. Via oxygen ion implantation, the carrier lifetime has been reduced to as short as 1 ps, corresponding to 1 THz of photodetector bandwidth. It has also been shown that copper dopants act as recombination centers in the silicon germanium.

  2. 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.

  3. 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.

  4. A Shape Memory Alloy Based Cryogenic Thermal Conduction Switch

    Science.gov (United States)

    Notardonato, W. U.; Krishnan, V. B.; Singh, J. D.; Woodruff, T. R.; Vaidyanathan, R.

    2005-01-01

    Shape memory alloys (SMAs) can produce large strains when deformed (e.g., up to 8%). Heating results in a phase transformation and associated recovery of all the accumulated strain. This strain recovery can occur against large forces, resulting in their use as actuators. Thus an SMA element can integrate both sensory and actuation functions, by inherently sensing a change in temperature and actuating by undergoing a shape change as a result of a temperature-induced phase transformation. Two aspects of our work on cryogenic SMAs are addressed here. First - a shape memory alloy based cryogenic thermal conduction switch for operation between dewars of liquid methane and liquid oxygen in a common bulkhead arrangement is discussed. Such a switch integrates the sensor element and the actuator element and can be used to create a variable thermal sink to other cryogenic tanks for liquefaction, densification, and zero boil-off systems for advanced spaceport applications. Second - fabrication via arc-melting and subsequent materials testing of SMAs with cryogenic transformation temperatures for use in the aforementioned switch is discussed.

  5. A Shape Memory Alloy Based Cryogenic Thermal Conduction Switch

    International Nuclear Information System (INIS)

    Krishnan, V.B.; Singh, J.D.; Woodruff, T.R.; Vaidyanathan, R.; Notardonato, W.U.

    2004-01-01

    Shape memory alloys (SMAs) can produce large strains when deformed (e.g., up to 8%). Heating results in a phase transformation and associated recovery of all the accumulated strain. This strain recovery can occur against large forces, resulting in their use as actuators. Thus an SMA element can integrate both sensory and actuation functions, by inherently sensing a change in temperature and actuating by undergoing a shape change as a result of a temperature-induced phase transformation. Two aspects of our work on cryogenic SMAs are addressed here. First - a shape memory alloy based cryogenic thermal conduction switch for operation between dewars of liquid methane and liquid oxygen in a common bulkhead arrangement is discussed. Such a switch integrates the sensor element and the actuator element and can be used to create a variable thermal sink to other cryogenic tanks for liquefaction, densification, and zero boil-off systems for advanced spaceport applications. Second - fabrication via arc-melting and subsequent materials testing of SMAs with cryogenic transformation temperatures for use in the aforementioned switch is discussed

  6. N-state random switching based on quantum tunnelling

    Science.gov (United States)

    Bernardo Gavito, Ramón; Jiménez Urbanos, Fernando; Roberts, Jonathan; Sexton, James; Astbury, Benjamin; Shokeir, Hamzah; McGrath, Thomas; Noori, Yasir J.; Woodhead, Christopher S.; Missous, Mohamed; Roedig, Utz; Young, Robert J.

    2017-08-01

    In this work, we show how the hysteretic behaviour of resonant tunnelling diodes (RTDs) can be exploited for new functionalities. In particular, the RTDs exhibit a stochastic 2-state switching mechanism that could be useful for random number generation and cryptographic applications. This behaviour can be scaled to N-bit switching, by connecting various RTDs in series. The InGaAs/AlAs RTDs used in our experiments display very sharp negative differential resistance (NDR) peaks at room temperature which show hysteresis cycles that, rather than having a fixed switching threshold, show a probability distribution about a central value. We propose to use this intrinsic uncertainty emerging from the quantum nature of the RTDs as a source of randomness. We show that a combination of two RTDs in series results in devices with three-state outputs and discuss the possibility of scaling to N-state devices by subsequent series connections of RTDs, which we demonstrate for the up to the 4-state case. In this work, we suggest using that the intrinsic uncertainty in the conduction paths of resonant tunnelling diodes can behave as a source of randomness that can be integrated into current electronics to produce on-chip true random number generators. The N-shaped I-V characteristic of RTDs results in a two-level random voltage output when driven with current pulse trains. Electrical characterisation and randomness testing of the devices was conducted in order to determine the validity of the true randomness assumption. Based on the results obtained for the single RTD case, we suggest the possibility of using multi-well devices to generate N-state random switching devices for their use in random number generation or multi-valued logic devices.

  7. An effective implementation scheme of just-in-time protocol for optical burst switching networks

    Science.gov (United States)

    Wu, Guiling; Li, Xinwan; Chen, Jian-Ping; Wang, Hui

    2005-02-01

    Optical burst switching (OBS) has been emerging as a promising technology that can effectively support the next generation IP-oriented transportation networks. JIT signaling protocol for OBS is relatively simple and easy to be implemented by hardware. This paper presented an effective scheme to implement the JIT protocol, which not only can effectively implement reservation and release of optical channels based on JIT, but also can process the failure of channel reservation and release due to loss of burst control packets. The scheme includes: (1) a BHP (burst head packet) path table is designed and built at each OBS node. It is used to guarantee the corresponding burst control packet, i.e. BHP, BEP (burst end packet) and BEP_ACK (BEP acknowledgement), to be transmitted in the same path. (2) The timed retransmission of BEP and the reversed deletion of the item in BHP path tables triggered by the corresponding BEP_ACK are combined to solve the problems caused by the loss of the signaling messages in channel reservation and release process. (3) Burst head packets and BEP_ACK are transmitted using "best-effort" method. Related signaling messages and their formats for the proposed scheme are also given.

  8. Effective preemptive scheduling scheme for optical burst-switched networks with cascaded wavelength conversion consideration

    Science.gov (United States)

    Gao, Xingbo

    2010-03-01

    We introduce a new preemptive scheduling technique for next-generation optical burst switching (OBS) networks considering the impact of cascaded wavelength conversions. It has been shown that when optical bursts are transmitted all optically from source to destination, each wavelength conversion performed along the lightpath may cause certain signal-to-noise deterioration. If the distortion of the signal quality becomes significant enough, the receiver would not be able to recover the original data. Accordingly, subject to this practical impediment, we improve a recently proposed fair channel scheduling algorithm to deal with the fairness problem and aim at burst loss reduction simultaneously in OBS environments. In our scheme, the dynamic priority associated with each burst is based on a constraint threshold and the number of already conducted wavelength conversions among other factors for this burst. When contention occurs, a new arriving superior burst may preempt another scheduled one according to their priorities. Extensive simulation results have shown that the proposed scheme further improves fairness and achieves burst loss reduction as well.

  9. 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.

  10. High-speed 2 × 2 silicon-based electro-optic switch with nanosecond switch time

    International Nuclear Information System (INIS)

    Xue-Jun, Xu; Shao-Wu, Chen; Hai-Hua, Xu; Yang, Sun; Yu-De, Yu; Jin-Zhong, Yu; Qi-Ming, Wang

    2009-01-01

    A 2 × 2 electro-optic switch is experimentally demonstrated using the optical structure of a Mach–Zehnder interferometer (MZI) based on a submicron rib waveguide and the electrical structure of a PIN diode on silicon-on-insulator (SOI). The switch behaviour is achieved through the plasma dispersion effect of silicon. The device has a modulation arm of 1 mm in length and cross-section of 400 nm×340 nm. The measurement results show that the switch has a V π L π figure of merit of 0.145 V·cm and the extinction ratios of two output ports and cross talk are 40 dB, 28 dB and −28 dB, respectively. A 3 dB modulation bandwidth of 90 MHz and a switch time of 6.8 ns for the rise edge and 2.7 ns for the fall edge are also demonstrated

  11. 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....

  12. Three-tier multi-granularity switching system based on PCE

    Science.gov (United States)

    Wang, Yubao; Sun, Hao; Liu, Yanfei

    2017-10-01

    With the growing demand for business communications, electrical signal processing optical path switching can't meet the demand. The multi-granularity switch system that can improve node routing and switching capabilities came into being. In the traditional network, each node is responsible for calculating the path; synchronize the whole network state, which will increase the burden on the network, so the concept of path calculation element (PCE) is proposed. The PCE is responsible for routing and allocating resources in the network1. In the traditional band-switched optical network, the wavelength is used as the basic routing unit, resulting in relatively low wavelength utilization. Due to the limitation of wavelength continuity, the routing design of the band technology becomes complicated, which directly affects the utilization of the system. In this paper, optical code granularity is adopted. There is no continuity of the optical code, and the number of optical codes is more flexible than the wavelength. For the introduction of optical code switching, we propose a Code Group Routing Entity (CGRE) algorithm. In short, the combination of three-tier multi-granularity optical switching system and PCE can simplify the network structure, reduce the node load, and enhance the network scalability and survivability. Realize the intelligentization of optical network.

  13. A hybrid optical switch architecture to integrate IP into optical networks to provide flexible and intelligent bandwidth on demand for cloud computing

    Science.gov (United States)

    Yang, Wei; Hall, Trevor J.

    2013-12-01

    The Internet is entering an era of cloud computing to provide more cost effective, eco-friendly and reliable services to consumer and business users. As a consequence, the nature of the Internet traffic has been fundamentally transformed from a pure packet-based pattern to today's predominantly flow-based pattern. Cloud computing has also brought about an unprecedented growth in the Internet traffic. In this paper, a hybrid optical switch architecture is presented to deal with the flow-based Internet traffic, aiming to offer flexible and intelligent bandwidth on demand to improve fiber capacity utilization. The hybrid optical switch is capable of integrating IP into optical networks for cloud-based traffic with predictable performance, for which the delay performance of the electronic module in the hybrid optical switch architecture is evaluated through simulation.

  14. Analysis of bi-directional piezoelectric-based converters for zero-voltage switching operation

    DEFF Research Database (Denmark)

    Ekhtiari, Marzieh; Zhang, Zhe; Andersen, Michael A. E.

    2016-01-01

    This paper deals with a thorough analysis of zerovoltage switching especially for bi-directional, inductorless, piezoelectric transformer-based switch-mode power supplies with a half-bridge topology. Practically, obtaining zero-voltage switching for all of the switches in a bi-directional piezoel......This paper deals with a thorough analysis of zerovoltage switching especially for bi-directional, inductorless, piezoelectric transformer-based switch-mode power supplies with a half-bridge topology. Practically, obtaining zero-voltage switching for all of the switches in a bi......-directional piezoelectric power converter is a difficult task. However, the analysis in this work will be convenient for overcoming this challenge. The analysis defines the zero-voltage region indicating the operating points whether or not soft switching can be met over the switching frequency and load range. For the first...... time, a comprehensive analysis is provided, which can be used as a design guideline for applying control techniques in order to drive switches in piezoelectric transformer-based converters. This study further conveys the proposed method to the region where all the switches can obtain soft switching...

  15. Interference mitigation enhancement of switched-based scheme in over-loaded femtocells

    KAUST Repository

    Gaaloul, Fakhreddine

    2012-06-01

    This paper proposes adequate methods to improve the interference mitigation capability of a recently investigated switched-based interference reduction scheme in short-range open-access and over-loaded femtocells. It is assumed that the available orthogonal channels for the femtocell network are distributed among operating access points in close vicinity, where each of which knows its allocated channels a priori. For the case when the feedback links are capacity-limited and the available channels can be universally shared and simultaneously used, the paper presents enhanced schemes to identify a channel to serve the desired 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 aiming to reduce the channels examination load. The performance of the proposed schemes is quantified and then compared with those of the single-threshold switched-based scheme via numerical and simulation results. © 2012 IEEE.

  16. Performance analysis of switching based hybrid FSO/RF transmission

    KAUST Repository

    Usman, Muneer

    2014-09-01

    Hybrid free space optical (FSO)/ radio frequency (RF) systems have emerged as a promising solution for high data rate wireless back haul.We present and analyze a switching based transmission scheme for hybrid FSO/RF system. Specifically, either FSO or RF link will be active at a certain time instance, with FSO link enjoying a higher priority. Analytical expressions have been obtained for the outage probability, average bit error rate and ergodic capacity for the resulting system. Numerical examples are presented to compare the performance of the hybrid scheme with FSO only scenario.

  17. Performance analysis of switching based hybrid FSO/RF transmission

    KAUST Repository

    Usman, Muneer; Yang, Hongchuan; Alouini, Mohamed-Slim

    2014-01-01

    Hybrid free space optical (FSO)/ radio frequency (RF) systems have emerged as a promising solution for high data rate wireless back haul.We present and analyze a switching based transmission scheme for hybrid FSO/RF system. Specifically, either FSO or RF link will be active at a certain time instance, with FSO link enjoying a higher priority. Analytical expressions have been obtained for the outage probability, average bit error rate and ergodic capacity for the resulting system. Numerical examples are presented to compare the performance of the hybrid scheme with FSO only scenario.

  18. 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.

  19. 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.

    Science.gov (United States)

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

    2014-12-01

    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. © 2014 American Society of Plant Biologists. All rights reserved.

  20. Engineering Silver Nanowire Networks: From Transparent Electrodes to Resistive Switching Devices.

    Science.gov (United States)

    Du, Haiwei; Wan, Tao; Qu, Bo; Cao, Fuyang; Lin, Qianru; Chen, Nan; Lin, Xi; Chu, Dewei

    2017-06-21

    Metal nanowires (NWs) networks with high conductance have shown potential applications in modern electronic components, especially the transparent electrodes over the past decade. In metal NW networks, the electrical connectivity of nanoscale NW junction can be modulated for various applications. In this work, silver nanowire (Ag NW) networks were selected to achieve the desired functions. The Ag NWs were first synthesized by a classic polyol process, and spin-coated on glass to fabricate transparent electrodes. The as-fabricated electrode showed a sheet resistance of 7.158 Ω □ -1 with an optical transmittance of 79.19% at 550 nm, indicating a comparable figure of merit (FOM, or Φ TC ) (13.55 × 10 -3 Ω -1 ). Then, two different post-treatments were designed to tune the Ag NWs for not only transparent electrode but also for threshold resistive switching (RS) application. On the one hand, the Ag NW film was mechanically pressed to significantly improve the conductance by reducing the junction resistance. On the other hand, an Ag@AgO x core-shell structure was deliberately designed by partial oxidation of Ag NWs through simple ultraviolet (UV)-ozone treatment. The Ag core can act as metallic interconnect and the insulating AgO x shell acts as a switching medium to provide a conductive pathway for Ag filament migration. By fabricating Ag/Ag@AgO x /Ag planar structure, a volatile threshold switching characteristic was observed and an on/off ratio of ∼100 was achieved. This work showed that through different post-treatments, Ag NW network can be engineered for diverse functions, transforming from transparent electrodes to RS devices.

  1. A numerical simulation model of valence-change-based resistive switching

    OpenAIRE

    Marchewka, Astrid

    2017-01-01

    Due to their superior scalability and performance, nanoscale resistive switches based on the valence-change mechanism are considered promising candidates for future nonvolatile memory and logic applications. These devices are metal-oxide-metal structures that can be reversibly switched between different resistance states by electrical signals. Typically, they contain one Schottky-like and one ohmic-like metal-oxide contact and exhibit bipolar switching. The switching mechanism and the initial...

  2. Enhanced just-in-time plus protocol for optical burst switching networks

    Science.gov (United States)

    Rodrigues, Joel J. P. C.; Gregório, José M. B.; Vasilakos, Athanasios V.

    2010-07-01

    We propose a new one-way resource reservation protocol for optical burst switching (OBS) networks, called Enhanced Just-in-Time Plus (E-JIT+). The protocol is described in detail, and its formal specification is presented, following an extended finite state machine approach. The performance evaluation of E-JIT+ is analyzed in comparison with other proposed OBS protocols (JIT+ and E-JIT) for the following network topologies: rings; degree-two, degree-three, and degree-four chordal rings; mesh-torus; NSFNET; ARPANET; FCCN-NET; and the European Optical Network. We evaluate and compare the performance of the different protocols in terms of burst loss probability, taking into account the most important OBS network parameters. It was shown that E-JIT+ performs better than available one-way resource reservation protocols for all the evaluated network topologies. Moreover, the scalability of E-JIT+ was observed, and when the network traffic increases, the burst loss probability also increases, leading to a worse network performance.

  3. On the fly all-optical packet switching based on hybrid WDM/OCDMA labeling scheme

    Science.gov (United States)

    Brahmi, Houssem; Giannoulis, Giannis; Menif, Mourad; Katopodis, Vasilis; Kalavrouziotis, Dimitrios; Kouloumentas, Christos; Groumas, Panos; Kanakis, Giannis; Stamatiadis, Christos; Avramopoulos, Hercules; Erasme, Didier

    2014-02-01

    We introduce a novel design of an all-optical packet routing node that allows for the selection and forwarding of optical packets based on the routing information contained in hybrid wavelength division multiplexing/optical code division multiple access (WDM/OCDMA) labels. A stripping paradigm of optical code-label is adopted. The router is built around an optical-code gate that consists in an optical flip-flop controlled by two fiber Bragg grating correlators and is combined with a Mach-Zehnder interferometer (MZI)-based forwarding gate. We experimentally verify the proof-of-principle operation of the proposed self-routing node under NRZ and OCDMA packet traffic conditions. The successful switching of elastic NRZ payload at 40 Gb/s controlled by DS-OCDMA coded labels and the forwarding operation of encoded data using EQC codes are presented. Proper auto-correlation functions are obtained with higher than 8.1 dB contrast ratio, suitable to efficiently trigger the latching device with a contrast ratio of 11.6 dB and switching times below 3.8 ns. Error-free operation is achieved with 1.5 dB penalty for 40 Gb/s NRZ data and with 2.1 dB penalty for DS-OCDMA packets. The scheme can further be applied to large-scale optical packet switching networks by exploiting efficient optical coders allocated at different WDM channels.

  4. 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.

  5. Optically beamformed beam-switched adaptive antennas for fixed and mobile broadband wireless access networks

    NARCIS (Netherlands)

    Piqueras, M.A.; Grosskopf, G.; Vidal, B.; Herrera Llorente, J.; Martinez, J.M.; Sanchis, P.; Polo, V.; Corral, J.L.; Marceaux, A.; Galière, J.; Lopez, J.; Enard, A.; Valard, J.-L.; Parillaud, O.; Estèbe, E.; Vodjdani, N.; Choi, M.-S.; Besten, den J.H.; Soares, F.M.; Smit, M.K.; Marti, J.

    2006-01-01

    In this paper, a 3-bit optical beamforming architecture based in 2×2 optical switches and dispersive media is proposed and demonstrated. The performance of this photonic beamformer is experimentally demonstrated at 42.7 GHz in both transmission and reception modes. The progress achieved for

  6. Equilibrium switching and mathematical properties of nonlinear interaction networks with concurrent antagonism and self-stimulation

    International Nuclear Information System (INIS)

    Rabajante, Jomar Fajardo; Talaue, Cherryl Ortega

    2015-01-01

    Graphical abstract: Display Omitted -- Highlights: •Properties of n-dimensional decision model of competitive interaction networks. •Graphical technique for component-wise and steady state stability analysis. •Search for parameter conditions that control equilibrium switching. •Illustrations of multi-stable systems and repressilators. -- Abstract: Concurrent decision-making model (CDM) of interaction networks with more than two antagonistic components represents various biological systems, such as gene interaction, species competition and mental cognition. The CDM model assumes sigmoid kinetics where every component stimulates itself but concurrently represses the others. Here we prove generic mathematical properties (e.g., location and stability of steady states) of n-dimensional CDM with either symmetric or asymmetric reciprocal antagonism between components. Significant modifications in parameter values serve as biological regulators for inducing steady state switching by driving a temporal state to escape an undesirable equilibrium. Increasing the maximal growth rate and decreasing the decay rate can expand the basin of attraction of a steady state that contains the desired dominant component. Perpetually adding an external stimulus could shut down multi-stability of the system which increases the robustness of the system against stochastic noise. We further show that asymmetric interaction forming a repressilator-type network generates oscillatory behavior

  7. 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...... during a rearrangement. When each inlet channel appears twice, the maximum number of connections to be moved is found. For a special class of inlet assignment patterns in the case of which each inlet channel appears three times, the maximum number of connections to be moved is also found. In the general...

  8. A tri-state optical switch for local area network communications

    Science.gov (United States)

    Simms, Garfield

    1993-01-01

    This novel structure is a heterojunction phototransistor which can be used as an emitter-detector, and when placed in a quiescent mode, the device becomes a passive transmitter. By varying the voltage bias, this novel device will switch between all three modes of operation. Such a device has broad application in network environments with operation speeds of less than 50 MHz and distances of less than 1 km, e.g. automobiles, airplanes, and intra-instrumentation. During this period, the emission mode for this device was studied and mathematically modeled.

  9. A plasma switch synchronous closing operations in high-voltage networks

    International Nuclear Information System (INIS)

    Mourente, P.

    1984-01-01

    Overvoltages and overcurrent arising in energizing or in fast reclosing operations are a concerning problem in high-voltage networks. Reduction of overvoltages and overcurrents is possible using the synchronous closing technique. Some attempts have been done to perform the synchronous closing with conventional circuit-breakers. But since the requirements to synchronous closing and to current interruption are very contradictory this technique is not yet a common practice. Three simple cases may be used as examples to show the benefits of synchronous closing; energizaton of grounded star capacitor bank; back-to-back switching of large capacitor banks; and fast reclosing on transmission lines

  10. Adaptive Backstepping-Based Neural Tracking Control for MIMO Nonlinear Switched Systems Subject to Input Delays.

    Science.gov (United States)

    Niu, Ben; Li, Lu

    2018-06-01

    This brief proposes a new neural-network (NN)-based adaptive output tracking control scheme for a class of disturbed multiple-input multiple-output uncertain nonlinear switched systems with input delays. By combining the universal approximation ability of radial basis function NNs and adaptive backstepping recursive design with an improved multiple Lyapunov function (MLF) scheme, a novel adaptive neural output tracking controller design method is presented for the switched system. The feature of the developed design is that different coordinate transformations are adopted to overcome the conservativeness caused by adopting a common coordinate transformation for all subsystems. It is shown that all the variables of the resulting closed-loop system are semiglobally uniformly ultimately bounded under a class of switching signals in the presence of MLF and that the system output can follow the desired reference signal. To demonstrate the practicability of the obtained result, an adaptive neural output tracking controller is designed for a mass-spring-damper system.

  11. High optical label switching add-drop multiplexer nodes with nanoseconds latency for 5G metro/access networks

    NARCIS (Netherlands)

    Calabretta, N.; Miao, W.; De Waardt, H.

    2016-01-01

    We present a novel optical add-drop multiplexer for next-generation metro/access networks by exploiting optical label switching technology. Experimental results of a ring network show nanoseconds add/drop operation including multicasting and power equalization of 50Gb/s data.

  12. Four Novel Zn (II Coordination Polymers Based on 4′-Ferrocenyl-3,2′:6′,3′′-Terpyridine: Engineering a Switch from 1D Helical Polymer Chain to 2D Network by Coordination Anion Modulation

    Directory of Open Access Journals (Sweden)

    Lufei Xiao

    2017-11-01

    Full Text Available Four novel ZnII coordination polymers, [(ZnCl22(L2]n (1, [(ZnBr22(L2]n (2, and [(ZnI22(L2]n (3 and {[Zn(SCN2]1.5(L3}n (4, have been synthesized based on 4′-ferrocenyl-3,2′:6′,3′′-terpyridine with ZnII ions and different coordination anions under similar ambient conditions. Their structures have been confirmed using single crystal X-ray diffraction analysis, showing that complexes 1–3 are one-dimensional (1D double-stranded metal ion helical polymer chains and complex 4 is of a two-dimensional (2D network. The structural transformations of them from a 1D polymer chain to a 2D network under the influence of the coordination anions has been systematic investigated. Furthermore, the optical band gaps have been measured by optical diffuse reflectance spectroscopy, revealing that the ligand and the complexes should have semiconductor properties.

  13. A New Topology for UPQC Based on Reduced-Switch-Count Converter

    OpenAIRE

    Ajami, Ali; Mahmoudi, Mohsen; Seyfi, Ebrahim; Atashbahar, Farid

    2014-01-01

    Recently, reduced switch count converter switch numerous advantages such as low cost and weight, small size and high reliability have been introduced to be used in unified power quality conditioner (UPQC). In this paper a novel topologyfor UPQC based on back-to-backB4 converter and its control system are proposed. The conventional UPQC consists of twelve switches while the proposed topology for UPQC has 8 switches. By reducing the number of switches, the price of the whole system and losses a...

  14. A New Topology for UPQC Based on Reduced-Switch-Count Converter

    OpenAIRE

    Ajami, Ali; Mahmoudi, Mohsen; Seyfi, Ebrahim; Atashbahar, Farid

    2015-01-01

    Recently, reduced switch count converter switch numerous advantages such as low cost and weight, small size and high reliability have been introduced to be used in unified power quality conditioner (UPQC). In this paper a novel topologyfor UPQC based on back-to-backB4 converter and its control system are proposed. The conventional UPQC consists of twelve switches while the proposed topology for UPQC has 8 switches. By reducing the number of switches, the price of the whole system and losses a...

  15. Dynamic optimum dead time in piezoelectric transformer-based switch-mode power supplies

    DEFF Research Database (Denmark)

    Ekhtiari, Marzieh; Andersen, Thomas; Andersen, Michael A. E.

    2016-01-01

    to charge and discharge the input capacitance of piezoelectric transformers in order to achieve zero-voltage switching. This paper proposes a method for detecting the optimum dead time in piezoelectric transformer-based switch-mode power supplies. The provision of sufficient dead time in every cycle......Soft switching is required to attain high efficiency in high-frequency power converters. Piezoelectric transformerbased converters can benefit from soft switching in terms of significantly diminished switching losses and stresses. Adequate dead time is needed in order to deliver sufficient energy...

  16. On-line Monitoring Device for High-voltage Switch Cabinet Partial Discharge Based on Pulse Current Method

    Science.gov (United States)

    Y Tao, S.; Zhang, X. Z.; Cai, H. W.; Li, P.; Feng, Y.; Zhang, T. C.; Li, J.; Wang, W. S.; Zhang, X. K.

    2017-12-01

    The pulse current method for partial discharge detection is generally applied in type testing and other off-line tests of electrical equipment at delivery. After intensive analysis of the present situation and existing problems of partial discharge detection in switch cabinets, this paper designed the circuit principle and signal extraction method for partial discharge on-line detection based on a high-voltage presence indicating systems (VPIS), established a high voltage switch cabinet partial discharge on-line detection circuit based on the pulse current method, developed background software integrated with real-time monitoring, judging and analyzing functions, carried out a real discharge simulation test on a real-type partial discharge defect simulation platform of a 10KV switch cabinet, and verified the sensitivity and validity of the high-voltage switch cabinet partial discharge on-line monitoring device based on the pulse current method. The study presented in this paper is of great significance for switch cabinet maintenance and theoretical study on pulse current method on-line detection, and has provided a good implementation method for partial discharge on-line monitoring devices for 10KV distribution network equipment.

  17. Experimental performance evaluation of software defined networking (SDN) based data communication networks for large scale flexi-grid optical networks.

    Science.gov (United States)

    Zhao, Yongli; He, Ruiying; Chen, Haoran; Zhang, Jie; Ji, Yuefeng; Zheng, Haomian; Lin, Yi; Wang, Xinbo

    2014-04-21

    Software defined networking (SDN) has become the focus in the current information and communication technology area because of its flexibility and programmability. It has been introduced into various network scenarios, such as datacenter networks, carrier networks, and wireless networks. Optical transport network is also regarded as an important application scenario for SDN, which is adopted as the enabling technology of data communication networks (DCN) instead of general multi-protocol label switching (GMPLS). However, the practical performance of SDN based DCN for large scale optical networks, which is very important for the technology selection in the future optical network deployment, has not been evaluated up to now. In this paper we have built a large scale flexi-grid optical network testbed with 1000 virtual optical transport nodes to evaluate the performance of SDN based DCN, including network scalability, DCN bandwidth limitation, and restoration time. A series of network performance parameters including blocking probability, bandwidth utilization, average lightpath provisioning time, and failure restoration time have been demonstrated under various network environments, such as with different traffic loads and different DCN bandwidths. The demonstration in this work can be taken as a proof for the future network deployment.

  18. Communication over the network of binary switches regulates the activation of A2A adenosine receptor.

    Directory of Open Access Journals (Sweden)

    Yoonji Lee

    2015-02-01

    Full Text Available Dynamics and functions of G-protein coupled receptors (GPCRs are accurately regulated by the type of ligands that bind to the orthosteric or allosteric binding sites. To glean the structural and dynamical origin of ligand-dependent modulation of GPCR activity, we performed total ~ 5 μsec molecular dynamics simulations of A2A adenosine receptor (A2AAR in its apo, antagonist-bound, and agonist-bound forms in an explicit water and membrane environment, and examined the corresponding dynamics and correlation between the 10 key structural motifs that serve as the allosteric hotspots in intramolecular signaling network. We dubbed these 10 structural motifs "binary switches" as they display molecular interactions that switch between two distinct states. By projecting the receptor dynamics on these binary switches that yield 2(10 microstates, we show that (i the receptors in apo, antagonist-bound, and agonist-bound states explore vastly different conformational space; (ii among the three receptor states the apo state explores the broadest range of microstates; (iii in the presence of the agonist, the active conformation is maintained through coherent couplings among the binary switches; and (iv to be most specific, our analysis shows that W246, located deep inside the binding cleft, can serve as both an agonist sensor and actuator of ensuing intramolecular signaling for the receptor activation. Finally, our analysis of multiple trajectories generated by inserting an agonist to the apo state underscores that the transition of the receptor from inactive to active form requires the disruption of ionic-lock in the DRY motif.

  19. Sequentially switching cell assemblies in random inhibitory networks of spiking neurons in the striatum.

    Science.gov (United States)

    Ponzi, Adam; Wickens, Jeff

    2010-04-28

    The striatum is composed of GABAergic medium spiny neurons with inhibitory collaterals forming a sparse random asymmetric network and receiving an excitatory glutamatergic cortical projection. Because the inhibitory collaterals are sparse and weak, their role in striatal network dynamics is puzzling. However, here we show by simulation of a striatal inhibitory network model composed of spiking neurons that cells form assemblies that fire in sequential coherent episodes and display complex identity-temporal spiking patterns even when cortical excitation is simply constant or fluctuating noisily. Strongly correlated large-scale firing rate fluctuations on slow behaviorally relevant timescales of hundreds of milliseconds are shown by members of the same assembly whereas members of different assemblies show strong negative correlation, and we show how randomly connected spiking networks can generate this activity. Cells display highly irregular spiking with high coefficients of variation, broadly distributed low firing rates, and interspike interval distributions that are consistent with exponentially tailed power laws. Although firing rates vary coherently on slow timescales, precise spiking synchronization is absent in general. Our model only requires the minimal but striatally realistic assumptions of sparse to intermediate random connectivity, weak inhibitory synapses, and sufficient cortical excitation so that some cells are depolarized above the firing threshold during up states. Our results are in good qualitative agreement with experimental studies, consistent with recently determined striatal anatomy and physiology, and support a new view of endogenously generated metastable state switching dynamics of the striatal network underlying its information processing operations.

  20. Hybrid Multiple Soft-Sensor Models of Grinding Granularity Based on Cuckoo Searching Algorithm and Hysteresis Switching Strategy

    Directory of Open Access Journals (Sweden)

    Jie-Sheng Wang

    2015-01-01

    Full Text Available According to the characteristics of grinding process and accuracy requirements of technical indicators, a hybrid multiple soft-sensor modeling method of grinding granularity is proposed based on cuckoo searching (CS algorithm and hysteresis switching (HS strategy. Firstly, a mechanism soft-sensor model of grinding granularity is deduced based on the technique characteristics and a lot of experimental data of grinding process. Meanwhile, the BP neural network soft-sensor model and wavelet neural network (WNN soft-sensor model are set up. Then, the hybrid multiple soft-sensor model based on the hysteresis switching strategy is realized. That is to say, the optimum model is selected as the current predictive model according to the switching performance index at each sampling instant. Finally the cuckoo searching algorithm is adopted to optimize the performance parameters of hysteresis switching strategy. Simulation results show that the proposed model has better generalization results and prediction precision, which can satisfy the real-time control requirements of grinding classification process.

  1. A Wireless Implantable Switched-Capacitor Based Optogenetic Stimulating System

    Science.gov (United States)

    Lee, Hyung-Min; Kwon, Ki-Yong; Li, Wen

    2015-01-01

    This paper presents a power-efficient implantable optogenetic interface using a wireless switched-capacitor based stimulating (SCS) system. The SCS efficiently charges storage capacitors directly from an inductive link and periodically discharges them into an array of micro-LEDs, providing high instantaneous power without affecting wireless link and system supply voltage. A custom-designed computer interface in LabVIEW environment wirelessly controls stimulation parameters through the inductive link, and an optrode array enables simultaneous neural recording along with optical stimulation. The 4-channel SCS system prototype has been implemented in a 0.35-μm CMOS process and combined with the optrode array. In vivo experiments involving light-induced local field potentials verified the efficacy of the SCS system. An implantable version of the SCS system with flexible hermetic sealing is under development for chronic experiments. PMID:25570099

  2. State-of-the-art piezoelectric transformer-based switch mode power supplies

    DEFF Research Database (Denmark)

    Ekhtiari, Marzieh; Zhang, Zhe; Andersen, Michael A. E.

    2014-01-01

    Inductorless switch mode power supplies based on piezoelectric transformers are used to replace conventional transformers in high power density switch mode power supplies. Even though piezoelectric-based converters exhibit a high d egree of nonlinearity, it is desirable to use piezoelectric transfo...... discusses power supplies with the trend evaluation of piezoelectric transformer-based converter topologies and control methods. The challenges of piezoelectric transformers regarding soft switching capability and nonlinearity are addressed. This paper can be used as a guideline f or choosing a proper...... topology of piezoelectric-based switch mode power supply and a control method for the required application....

  3. Optical switching based on the manipulation of microparticles in a colloidal liquid using strong scattering force

    International Nuclear Information System (INIS)

    Liu Jin; Liu Zheng-Qi; Feng Tian-Hua; Dai Qiao-Feng; Wu Li-Jun; Lan Sheng

    2010-01-01

    This paper demonstrates the realization of an optical switch by optically manipulating a large number of polystyrene spheres contained in a capillary. The strong scattering force exerted on polystyrene spheres with a large diameter of 4.3 μm is employed to realize the switching operation. A transparent window is opened for the signal light when the polystyrene spheres originally located at the beam centre are driven out of the beam region by the strong scattering force induced by the control light. The switching dynamics under different incident powers is investigated and compared with that observed in the optical switch based on the formation of optical matter. It is found that a large extinction ratio of ∼ 30 dB and fast switching-on and switching-off times can be achieved in this type of switch. (classical areas of phenomenology)

  4. 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.

  5. Communication Network Architectures Based on Ethernet Passive Optical Network for Offshore Wind Power Farms

    Directory of Open Access Journals (Sweden)

    Mohamed A. Ahmed

    2016-03-01

    Full Text Available Nowadays, with large-scale offshore wind power farms (WPFs becoming a reality, more efforts are needed to maintain a reliable communication network for WPF monitoring. Deployment topologies, redundancy, and network availability are the main items to enhance the communication reliability between wind turbines (WTs and control centers. Traditional communication networks for monitoring and control (i.e., supervisory control and data acquisition (SCADA systems using switched gigabit Ethernet will not be sufficient for the huge amount of data passing through the network. In this paper, the optical power budget, optical path loss, reliability, and network cost of the proposed Ethernet Passive Optical Network (EPON-based communication network for small-size offshore WPFs have been evaluated for five different network architectures. The proposed network model consists of an optical network unit device (ONU deployed on the WT side for collecting data from different internal networks. All ONUs from different WTs are connected to a central optical line terminal (OLT, placed in the control center. There are no active electronic elements used between the ONUs and the OLT, which reduces the costs and complexity of maintenance and deployment. As fiber access networks without any protection are characterized by poor reliability, three different protection schemes have been configured, explained, and discussed. Considering the cost of network components, the total implementation expense of different architectures with, or without, protection have been calculated and compared. The proposed network model can significantly contribute to the communication network architecture for next generation WPFs.

  6. 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

  7. Multiobjective planning of distribution networks incorporating switches and protective devices using a memetic optimization

    International Nuclear Information System (INIS)

    Pombo, A. Vieira; Murta-Pina, João; Pires, V. Fernão

    2015-01-01

    A multi-objective planning approach for the reliability of electric distribution networks using a memetic optimization is presented. In this reliability optimization, the type of the equipment (switches or reclosers) and their location are optimized. The multiple objectives considered to find the optimal values for these planning variables are the minimization of the total equipment cost and at the same time the minimization of two distribution network reliability indexes. The reliability indexes are the system average interruption frequency index (SAIFI) and system average interruption duration index (SAIDI). To solve this problem a memetic evolutionary algorithm is proposed, which combines the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) with a local search algorithm. The obtained Pareto-optimal front contains solutions of different trade-offs with respect to the three objectives. A real distribution network is used to test the proposed algorithm. The obtained results show that this approach allows the utility to obtain the optimal type and location of the equipments to achieve the best reliability with the lower cost. - Highlights: • Reliability indexes SAIFI and SAIDI and Equipment Cost are optimized. • Optimization of equipment type, number and location on a MV network. • Memetic evolutionary algorithm with a local search algorithm is proposed. • Pareto optimal front solutions with respect to the three objective functions

  8. 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.

  9. Scalable optical switches for computing applications

    NARCIS (Netherlands)

    White, I.H.; Aw, E.T.; Williams, K.A.; Wang, Haibo; Wonfor, A.; Penty, R.V.

    2009-01-01

    A scalable photonic interconnection network architecture is proposed whereby a Clos network is populated with broadcast-and-select stages. This enables the efficient exploitation of an emerging class of photonic integrated switch fabric. A low distortion space switch technology based on recently

  10. Wireless Chalcogenide Nanoionic-Based Radio-Frequency Switch

    Science.gov (United States)

    Nessel, James; Miranda, Felix

    2013-01-01

    A new nonvolatile nanoionic switch is powered and controlled through wireless radio-frequency (RF) transmission. A thin layer of chalcogenide glass doped with a metal ion, such as silver, comprises the operational portion of the switch. For the switch to function, an oxidizable electrode is made positive (anode) with respect to an opposing electrode (cathode) when sufficient bias, typically on the order of a few tenths of a volt or more, is applied. This action causes the metal ions to flow toward the cathode through a coordinated hopping mechanism. At the cathode, a reduction reaction occurs to form a metal deposit. This metal deposit creates a conductive path that bridges the gap between electrodes to turn the switch on. Once this conductive path is formed, no further power is required to maintain it. To reverse this process, the metal deposit is made positive with respect to the original oxidizable electrode, causing the dissolution of the metal bridge thereby turning the switch off. Once the metal deposit has been completely dissolved, the process self-terminates. This switching process features the following attributes. It requires very little to change states (i.e., on and off). Furthermore, no power is required to maintain the states; hence, the state of the switch is nonvolatile. Because of these attributes the integration of a rectenna to provide the necessary power and control is unique to this embodiment. A rectenna, or rectifying antenna, generates DC power from an incident RF signal. The low voltages and power required for the nanoionic switch control are easily generated from this system and provide the switch with a novel capability to be operated and powered from an external wireless device. In one realization, an RF signal of a specific frequency can be used to set the switch into an off state, while another frequency can be used to set the switch to an on state. The wireless, miniaturized, and nomoving- part features of this switch make it

  11. Organization of the channel-switching process in parallel computer systems based on a matrix optical switch

    Science.gov (United States)

    Golomidov, Y. V.; Li, S. K.; Popov, S. A.; Smolov, V. B.

    1986-01-01

    After a classification and analysis of electronic and optoelectronic switching devices, the design principles and structure of a matrix optical switch is described. The switching and pair-exclusion operations in this type of switch are examined, and a method for the optical switching of communication channels is elaborated. Finally, attention is given to the structural organization of a parallel computer system with a matrix optical switch.

  12. Switching theory-based steganographic system for JPEG images

    Science.gov (United States)

    Cherukuri, Ravindranath C.; Agaian, Sos S.

    2007-04-01

    Cellular communications constitute a significant portion of the global telecommunications market. Therefore, the need for secured communication over a mobile platform has increased exponentially. Steganography is an art of hiding critical data into an innocuous signal, which provide answers to the above needs. The JPEG is one of commonly used format for storing and transmitting images on the web. In addition, the pictures captured using mobile cameras are in mostly in JPEG format. In this article, we introduce a switching theory based steganographic system for JPEG images which is applicable for mobile and computer platforms. The proposed algorithm uses the fact that energy distribution among the quantized AC coefficients varies from block to block and coefficient to coefficient. Existing approaches are effective with a part of these coefficients but when employed over all the coefficients they show there ineffectiveness. Therefore, we propose an approach that works each set of AC coefficients with different frame work thus enhancing the performance of the approach. The proposed system offers a high capacity and embedding efficiency simultaneously withstanding to simple statistical attacks. In addition, the embedded information could be retrieved without prior knowledge of the cover image. Based on simulation results, the proposed method demonstrates an improved embedding capacity over existing algorithms while maintaining a high embedding efficiency and preserving the statistics of the JPEG image after hiding information.

  13. 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.

  14. Location based Network Optimizations for Mobile Wireless Networks

    DEFF Research Database (Denmark)

    Nielsen, Jimmy Jessen

    selection in Wi-Fi networks and predictive handover optimization in heterogeneous wireless networks. The investigations in this work have indicated that location based network optimizations are beneficial compared to typical link measurement based approaches. Especially the knowledge of geographical...

  15. 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.

  16. An asynchronous data-driven event-building scheme based on ATM switching fabrics

    International Nuclear Information System (INIS)

    Letheren, M.; Christiansen, J.; Mandjavidze, I.; Verhille, H.; De Prycker, M.; Pauwels, B.; Petit, G.; Wright, S.; Lumley, J.

    1994-01-01

    The very high data rates expected in experiments at the next generation of high luminosity hadron colliders will be handled by pipelined front-end readout electronics and multiple levels (2 or 3) of triggering. A variety of data acquisition architectures have been proposed for use downstream of the first level trigger. Depending on the architecture, the aggregate bandwidths required for event building are expected to be of the order 10--100 Gbit/s. Here, an Asynchronous Transfer Mode (ATM) packet-switching network technology is proposed as the interconnect for building high-performance, scalable data acquisition architectures. This paper introduces the relevant characteristics of ATM and describes components for the construction of an ATM-based event builder: (1) a multi-path, self-routing, scalable ATM switching fabric, (2) an experimental high performance workstation ATM-interface, and (3) a VMEbus ATM-interface. The requirement for traffic shaping in ATM-based event-builders is discussed and an analysis of the performance of several such schemes is presented

  17. Distributed Synchronization in Networks of Agent Systems With Nonlinearities and Random Switchings.

    Science.gov (United States)

    Tang, Yang; Gao, Huijun; Zou, Wei; Kurths, Jürgen

    2013-02-01

    In this paper, the distributed synchronization problem of networks of agent systems with controllers and nonlinearities subject to Bernoulli switchings is investigated. Controllers and adaptive updating laws injected in each vertex of networks depend on the state information of its neighborhood. Three sets of Bernoulli stochastic variables are introduced to describe the occurrence probabilities of distributed adaptive controllers, updating laws and nonlinearities, respectively. By the Lyapunov functions method, we show that the distributed synchronization of networks composed of agent systems with multiple randomly occurring nonlinearities, multiple randomly occurring controllers, and multiple randomly occurring updating laws can be achieved in mean square under certain criteria. The conditions derived in this paper can be solved by semi-definite programming. Moreover, by mathematical analysis, we find that the coupling strength, the probabilities of the Bernoulli stochastic variables, and the form of nonlinearities have great impacts on the convergence speed and the terminal control strength. The synchronization criteria and the observed phenomena are demonstrated by several numerical simulation examples. In addition, the advantage of distributed adaptive controllers over conventional adaptive controllers is illustrated.

  18. Analysis of the packet formation process in packet-switched networks

    Science.gov (United States)

    Meditch, J. S.

    Two new queueing system models for the packet formation process in packet-switched telecommunication networks are developed, and their applications in process stability, performance analysis, and optimization studies are illustrated. The first, an M/M/1 queueing system characterization of the process, is a highly aggregated model which is useful for preliminary studies. The second, a marked extension of an earlier M/G/1 model, permits one to investigate stability, performance characteristics, and design of the packet formation process in terms of the details of processor architecture, and hardware and software implementations with processor structure and as many parameters as desired as variables. The two new models together with the earlier M/G/1 characterization span the spectrum of modeling complexity for the packet formation process from basic to advanced.

  19. Multiple-mode reconfigurable electro-optic switching network for optical fiber sensor array

    Science.gov (United States)

    Chen, Ray T.; Wang, Michael R.; Jannson, Tomasz; Baumbick, Robert

    1991-01-01

    This paper reports the first switching network compatible with multimode fibers. A one-to-many cascaded reconfigurable interconnection was built. A thin glass substrate was used as the guiding medium which provides not only higher coupling efficiency from multimode fiber to waveguide but also better tolerance of phase-matching conditions. Involvement of a total-internal-reflection hologram and multimode waveguide eliminates interface problems between fibers and waveguides. The DCG polymer graft has proven to be reliable from -180 C to +200 C. Survivability of such an electrooptic system in harsh environments is further ensured. LiNbO3 was chosen as the E-O material because of its stability at high temperatures (phase-transition temperature of more than 1000 C) and maturity of E-O device technology. Further theoretical calculation was conducted to provide the optimal interaction length and device capacitance.

  20. Immobilizing Organic-Based Molecular Switches into Metal-Organic Frameworks: A Promising Strategy for Switching in Solid State.

    Science.gov (United States)

    Gui, Bo; Meng, Yi; Xie, Yang; Du, Ke; Sue, Andrew C-H; Wang, Cheng

    2018-01-01

    Organic-based molecular switches (OMS) are essential components for the ultimate miniaturization of nanoscale electronics and devices. For practical applications, it is often necessary for OMS to be incorporated into functional solid-state materials. However, the switching characteristics of OMS in solution are usually not transferrable to the solid state, presumably because of spatial confinement or inefficient conversion in densely packed solid phase. A promising way to circumvent this issue is harboring the functional OMS within the robust and porous environment of metal-organic frameworks (MOFs) as their organic components. In this feature article, recent research progress of OMS-based MOFs is briefly summarized. The switching behaviors of OMS under different stimuli (e.g., light, redox, pH, etc.) in the MOF state are first introduced. After that, the technological applications of these OMS-based MOFs in different areas, including CO 2 adsorption, gas separation, drug delivery, photodynamic therapy, and sensing, are outlined. Finally, perspectives and future challenges are discussed in the conclusion. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Design and implementation of optical switches based on nonlinear plasmonic ring resonators: Circular, square and octagon

    Science.gov (United States)

    Ghadrdan, Majid; Mansouri-Birjandi, Mohammad Ali

    2018-05-01

    In this paper, all-optical plasmonic switches (AOPS) based on various configurations of circular, square and octagon nonlinear plasmonic ring resonators (NPRR) were proposed and numerically investigated. Each of these configurations consisted of two metal-insulator-metal (MIM) waveguides coupled to each other by a ring resonator (RR). Nonlinear Kerr effect was used to show switching performance of the proposed NPRR. The result showed that the octagon switch structure had lower threshold power and higher transmission ratio than square and circular switch structures. The octagon switch structure had a low threshold power equal to 7.77 MW/cm2 and the high transmission ratio of approximately 0.6. Therefore, the octagon switch structure was an appropriate candidate to be applied in optical integration circuits as an AOPS.

  2. Photonic-crystal switch divider based on Ge2Sb2Te5 thin films.

    Science.gov (United States)

    Ma, Beijiao; Zhang, Peiqing; Wang, Hui; Zhang, Tengyu; Zeng, Jianghui; Zhang, Qian; Wang, Guoxiang; Xu, Peipeng; Zhang, Wei; Dai, Shixun

    2016-11-10

    A three-port phase-change photonic-crystal switch divider based on Ge2Sb2Te5 chalcogenide thin film was proposed. The chalcogenide material used was determined to have a high refractive index and fast phase-change speed by using laser radiation. The structure with a T-junction cavity was used to achieve three switch functions: switching "ON" in only one output port, switching "OFF" in both output ports, and dividing signals into two output ports. The transmission properties of the designed device at 2.0 μm were studied by the finite difference time domain method, which showed that the switch divider can achieve very high switching efficiency by optimizing T-junction cavity parameters. The scaling laws of photonic crystals revealed that the operating wavelength of the designed structure can be easily extended to another wavelength in the midinfrared region.

  3. Suggestions for Layout and Functional Behavior of Software-Based Voice Switch Keysets

    Science.gov (United States)

    Scott, David W.

    2010-01-01

    Marshall Space Flight Center (MSFC) provides communication services for a number of real time environments, including Space Shuttle Propulsion support and International Space Station (ISS) payload operations. In such settings, control team members speak with each other via multiple voice circuits or loops. Each loop has a particular purpose and constituency, and users are assigned listen and/or talk capabilities for a given loop based on their role in fulfilling the purpose. A voice switch is a given facility's hardware and software that supports such communication, and may be interconnected with other facilities switches to create a large network that, from an end user perspective, acts like a single system. Since users typically monitor and/or respond to several voice loops concurrently for hours on end and real time operations can be very dynamic and intense, it s vital that a control panel or keyset for interfacing with the voice switch be a servant that reduces stress, not a master that adds it. Implementing the visual interface on a computer screen provides tremendous flexibility and configurability, but there s a very real risk of overcomplication. (Remember how office automation made life easier, which led to a deluge of documents that made life harder?) This paper a) discusses some basic human factors considerations related to keysets implemented as application software windows, b) suggests what to standardize at the facility level and what to leave to the user's preference, and c) provides screen shot mockups for a robust but reasonably simple user experience. Concepts apply to keyset needs in almost any type of operations control or support center.

  4. Compact Si-based asymmetric MZI waveguide on SOI as a thermo-optical switch

    Science.gov (United States)

    Rizal, C. S.; Niraula, B.

    2018-03-01

    A compact low power consuming asymmetric MZI based optical modulator with fast response time has been proposed on SOI platform. The geometrical and performance characteristics were analyzed in depth and optimized using coupled mode analysis and FDTD simulation tools, respectively. It was tested with and without implementation of thermo-optic (TO) effect. The device showed good frequency modulating characteristics when tested without the implementation of the TO effect. The fabricated device showed quality factor, Q ≈ 10,000, and this value is comparable to the Q of the device simulated with 25% transmission loss, showing FSR of 0.195 nm, FWHM ≈ 0.16 nm, and ER of 13 dB. With TO effect, it showed temperature sensitivity of 0.01 nm/°C and FSR of 0.19 nm. With the heater length of 4.18 mm, the device required 0.26 mW per π shift power with a switching voltage of 0.309 V, response time of 10 μ, and figure-of-merit of 2.6 mW μs. All of these characteristics make this device highly attractive for use in integrated Si photonics network as optical switch and wavelength modulator.

  5. 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

    2018-01-15

    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 that 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 pseudophosphorylation 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 phosphodependent mechanisms governing tau's ability to trigger microtubule organization and reveal that disease-related modifications of tau promote specific microtubule organizations that may have a deleterious impact during neurodegeneration. © 2018 Prezel, Elie, et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  6. A Switched-Capacitor Based High Conversion Ratio Converter for Renewable Energy Applications

    DEFF Research Database (Denmark)

    Li, Kerui; Yin, Zhijian; Yang, Yongheng

    2017-01-01

    A high step-up switched-capacitor based converter is proposed in this paper. The proposed converter features high conversion ratio, low voltage stress and continuous input current, which makes it very suitable for renewable energy applications like photovoltaic systems. More importantly...... voltage gain, low voltage stress on the switches, continuous input current, and relatively high efficiency....

  7. Measurement and Evidence of Computer-Based Task Switching and Multitasking by "Net Generation" Students

    Science.gov (United States)

    Judd, Terry; Kennedy, Gregor

    2011-01-01

    Logs of on-campus computer and Internet usage were used to conduct a study of computer-based task switching and multitasking by undergraduate medical students. A detailed analysis of over 6000 individual sessions revealed that while a majority of students engaged in both task switching and multitasking behaviours, they did so less frequently than…

  8. Enhanced protein and biochemical production using CRISPRi-based growth switches

    DEFF Research Database (Denmark)

    Li, Songyuan; Jendresen, Christian Bille; Grünberger, Alexander

    2016-01-01

    functionality of the growth switches. Decoupling of growth from production of biochemicals was demonstrated for mevalonate, a precursor for isoprenoid compounds. Mass yield of mevalonate was increased by 41%, and production was maintained for more than 45 h after activation of the pyrF-based growth switch...

  9. Sinc-function based Network

    DEFF Research Database (Denmark)

    Madsen, Per Printz

    1998-01-01

    The purpose of this paper is to describe a neural network (SNN), that is based on Shannons ideas of reconstruction of a real continuous function from its samples. The basic function, used in this network, is the Sinc-function. Two learning algorithms are described. A simple one called IM...

  10. A progress report of the switch-based data acquisition system prototype project and the application of switches from industry to high-energy physics event building

    International Nuclear Information System (INIS)

    Barsotti, E.; Booth, A.; Bowden, M.; Swoboda, C.

    1990-01-01

    A prototype of a data acquisition system based on a new scalable, highly-parallel, open-system architecture is being developed at Fermilab. The major component of the new architecture, the parallel event builder, is based on a telecommunications industry technique used in the implementation of switching systems, a barrel-shift switch. The architecture is scalable both in the expandability of the number of input channels and in the throughput of the system. Because of its scalability, the system is well suited for low to high-rate experiments, test beams and all SSC detectors. The architecture is open in that as new technologies are developed and made into commercial products (e.g., arrays of processors and workstations and standard data links), these new products can be easily integrated into the system with minimal system modifications and no modifications to the system's basic architecture. Scalability and openness should guarantee that the data acquisition system does not become obsolete during the lifetime of the experiment. The paper first gives a description of the architecture and the prototype project and then details both the prototype project's software and hardware status including details of some architecture simulation studies. Suggestions for future R and D work on the new data acquisition system architecture are then described. The paper concludes by examining interconnection networks from industry and their application to event building and to other areas of high-energy physics data acquisition systems

  11. State Recognition of High Voltage Isolation Switch Based on Background Difference and Iterative Search

    Science.gov (United States)

    Xu, Jiayuan; Yu, Chengtao; Bo, Bin; Xue, Yu; Xu, Changfu; Chaminda, P. R. Dushantha; Hu, Chengbo; Peng, Kai

    2018-03-01

    The automatic recognition of the high voltage isolation switch by remote video monitoring is an effective means to ensure the safety of the personnel and the equipment. The existing methods mainly include two ways: improving monitoring accuracy and adopting target detection technology through equipment transformation. Such a method is often applied to specific scenarios, with limited application scope and high cost. To solve this problem, a high voltage isolation switch state recognition method based on background difference and iterative search is proposed in this paper. The initial position of the switch is detected in real time through the background difference method. When the switch starts to open and close, the target tracking algorithm is used to track the motion trajectory of the switch. The opening and closing state of the switch is determined according to the angle variation of the switch tracking point and the center line. The effectiveness of the method is verified by experiments on different switched video frames of switching states. Compared with the traditional methods, this method is more robust and effective.

  12. A Switched Capacitor Based AC/DC Resonant Converter for High Frequency AC Power Generation

    Directory of Open Access Journals (Sweden)

    Cuidong Xu

    2015-09-01

    Full Text Available A switched capacitor based AC-DC resonant power converter is proposed for high frequency power generation output conversion. This converter is suitable for small scale, high frequency wind power generation. It has a high conversion ratio to provide a step down from high voltage to low voltage for easy use. The voltage conversion ratio of conventional switched capacitor power converters is fixed to n, 1/n or −1/n (n is the switched capacitor cell. In this paper, A circuit which can provide n, 1/n and 2n/m of the voltage conversion ratio is presented (n is stepping up the switched capacitor cell, m is stepping down the switching capacitor cell. The conversion ratio can be changed greatly by using only two switches. A resonant tank is used to assist in zero current switching, and hence the current spike, which usually exists in a classical switching switched capacitor converter, can be eliminated. Both easy operation and efficiency are possible. Principles of operation, computer simulations and experimental results of the proposed circuit are presented. General analysis and design methods are given. The experimental result verifies the theoretical analysis of high frequency AC power generation.

  13. High frequency modulation circuits based on photoconductive wide bandgap switches

    Science.gov (United States)

    Sampayan, Stephen

    2018-02-13

    Methods, systems, and devices for high voltage and/or high frequency modulation. In one aspect, an optoelectronic modulation system includes an array of two or more photoconductive switch units each including a wide bandgap photoconductive material coupled between a first electrode and a second electrode, a light source optically coupled to the WBGP material of each photoconductive switch unit via a light path, in which the light path splits into multiple light paths to optically interface with each WBGP material, such that a time delay of emitted light exists along each subsequent split light path, and in which the WBGP material conducts an electrical signal when a light signal is transmitted to the WBGP material, and an output to transmit the electrical signal conducted by each photoconductive switch unit. The time delay of the photons emitted through the light path is substantially equivalent to the time delay of the electrical signal.

  14. A network flow model for load balancing in circuit-switched multicomputers

    Science.gov (United States)

    Bokhari, Shahid H.

    1990-01-01

    In multicomputers that utilize circuit switching or wormhole routing, communication overhead depends largely on link contention - the variation due to distance between nodes is negligible. This has a major impact on the load balancing problem. In this case, there are some nodes with excess load (sources) and others with deficit load (sinks) and it is required to find a matching of sources to sinks that avoids contention. The problem is made complex by the hardwired routing on currently available machines: the user can control only which nodes communicate but not how the messages are routed. Network flow models of message flow in the mesh and the hypercube were developed to solve this problem. The crucial property of these models is the correspondence between minimum cost flows and correctly routed messages. To solve a given load balancing problem, a minimum cost flow algorithm is applied to the network. This permits one to determine efficiently a maximum contention free matching of sources to sinks which, in turn, tells one how much of the given imbalance can be eliminated without contention.

  15. A valley-filtering switch based on strained graphene.

    Science.gov (United States)

    Zhai, Feng; Ma, Yanling; Zhang, Ying-Tao

    2011-09-28

    We investigate valley-dependent transport through a graphene sheet modulated by both the substrate strain and the fringe field of two parallel ferromagnetic metal (FM) stripes. When the magnetizations of the two FM stripes are switched from the parallel to the antiparallel alignment, the total conductance, valley polarization and valley conductance excess change greatly over a wide range of Fermi energy, which results from the dependence of the valley-related transmission suppression on the polarity configuration of inhomogeneous magnetic fields. Thus the proposed structure exhibits the significant features of a valley-filtering switch and a magnetoresistance device.

  16. A valley-filtering switch based on strained graphene

    International Nuclear Information System (INIS)

    Zhai Feng; Ma Yanling; Zhang Yingtao

    2011-01-01

    We investigate valley-dependent transport through a graphene sheet modulated by both the substrate strain and the fringe field of two parallel ferromagnetic metal (FM) stripes. When the magnetizations of the two FM stripes are switched from the parallel to the antiparallel alignment, the total conductance, valley polarization and valley conductance excess change greatly over a wide range of Fermi energy, which results from the dependence of the valley-related transmission suppression on the polarity configuration of inhomogeneous magnetic fields. Thus the proposed structure exhibits the significant features of a valley-filtering switch and a magnetoresistance device. (paper)

  17. Method of optimum channel switching in equipment of infocommunication network in conditions of cyber attacks to their telecommunication infrastructure.

    Science.gov (United States)

    Kochedykov, S. S.; Noev, A. N.; Dushkin, A. V.; Gubin, I. A.

    2018-05-01

    On the basis of the mathematical graph theory, the method of optimum switching of infocommunication networks in the conditions of cyber attacks is developed. The idea of representation of a set of possible ways on the graph in the form of the multilevel tree ordered by rules of algebra of a logic theory is the cornerstone of a method. As a criterion of optimization, the maximum of network transmission capacity to which assessment Ford- Falkerson's theorem is applied is used. The method is realized in the form of a numerical algorithm, which can be used not only for design, but also for operational management of infocommunication networks in conditions of violation of the functioning of their switching centers.

  18. Digital to analog resistive switching transition induced by graphene buffer layer in strontium titanate based devices.

    Science.gov (United States)

    Wan, Tao; Qu, Bo; Du, Haiwei; Lin, Xi; Lin, Qianru; Wang, Da-Wei; Cazorla, Claudio; Li, Sean; Liu, Sidong; Chu, Dewei

    2018-02-15

    Resistive switching behaviour can be classified into digital and analog switching based on its abrupt and gradual resistance change characteristics. Realizing the transition from digital to analog switching in the same device is essential for understanding and controlling the performance of the devices with various switching mechanisms. Here, we investigate the resistive switching in a device made with strontium titanate (SrTiO 3 ) nanoparticles using X-ray diffractometry, scanning electron microscopy, Raman spectroscopy, and direct electrical measurements. It is found that the well-known rupture/formation of Ag filaments is responsible for the digital switching in the device with Ag as the top electrode. To modulate the switching performance, we insert a reduced graphene oxide layer between SrTiO 3 and the bottom FTO electrode owing to its good barrier property for the diffusion of Ag ions and high out-of-plane resistance. In this case, resistive switching is changed from digital to analog as determined by the modulation of interfacial resistance under applied voltage. Based on that controllable resistance, potentiation and depression behaviours are implemented as well. This study opens up new ways for the design of multifunctional devices which are promising for memory and neuromorphic computing applications. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Status and Prospects of ZnO-Based Resistive Switching Memory Devices

    Science.gov (United States)

    Simanjuntak, Firman Mangasa; Panda, Debashis; Wei, Kung-Hwa; Tseng, Tseung-Yuen

    2016-08-01

    In the advancement of the semiconductor device technology, ZnO could be a prospective alternative than the other metal oxides for its versatility and huge applications in different aspects. In this review, a thorough overview on ZnO for the application of resistive switching memory (RRAM) devices has been conducted. Various efforts that have been made to investigate and modulate the switching characteristics of ZnO-based switching memory devices are discussed. The use of ZnO layer in different structure, the different types of filament formation, and the different types of switching including complementary switching are reported. By considering the huge interest of transparent devices, this review gives the concrete overview of the present status and prospects of transparent RRAM devices based on ZnO. ZnO-based RRAM can be used for flexible memory devices, which is also covered here. Another challenge in ZnO-based RRAM is that the realization of ultra-thin and low power devices. Nevertheless, ZnO not only offers decent memory properties but also has a unique potential to be used as multifunctional nonvolatile memory devices. The impact of electrode materials, metal doping, stack structures, transparency, and flexibility on resistive switching properties and switching parameters of ZnO-based resistive switching memory devices are briefly compared. This review also covers the different nanostructured-based emerging resistive switching memory devices for low power scalable devices. It may give a valuable insight on developing ZnO-based RRAM and also should encourage researchers to overcome the challenges.

  20. Superconducting spin switch based on superconductor-ferromagnet nanostructures for spintronics

    International Nuclear Information System (INIS)

    Kehrle, Jan; Mueller, Claus; Obermeier, Guenter; Schreck, Matthias; Gsell, Stefan; Horn, Siegfried; Tidecks, Reinhard; Zdravkov, Vladimir; Morari, Roman; Sidorencko, Anatoli; Prepelitsa, Andrei; Antropov, Evgenii; Socrovisciiuc, Alexei; Nold, Eberhard; Tagirov, Lenar

    2011-01-01

    Very rapid developing area, spintronics, needs new devices, based on new physical principles. One of such devices - a superconducting spin-switch, consists of ferromagnetic and superconducting layers, and is based on a new phenomenon - reentrant superconductivity. The tuning of the superconducting and ferromagnetic layers thickness is investigated to optimize superconducting spin-switch effect for Nb/Cu 41 Ni 59 based nanoscale layered systems.

  1. Network-based functional enrichment

    Directory of Open Access Journals (Sweden)

    Poirel Christopher L

    2011-11-01

    Full Text Available Abstract Background Many methods have been developed to infer and reason about molecular interaction networks. These approaches often yield networks with hundreds or thousands of nodes and up to an order of magnitude more edges. It is often desirable to summarize the biological information in such networks. A very common approach is to use gene function enrichment analysis for this task. A major drawback of this method is that it ignores information about the edges in the network being analyzed, i.e., it treats the network simply as a set of genes. In this paper, we introduce a novel method for functional enrichment that explicitly takes network interactions into account. Results Our approach naturally generalizes Fisher’s exact test, a gene set-based technique. Given a function of interest, we compute the subgraph of the network induced by genes annotated to this function. We use the sequence of sizes of the connected components of this sub-network to estimate its connectivity. We estimate the statistical significance of the connectivity empirically by a permutation test. We present three applications of our method: i determine which functions are enriched in a given network, ii given a network and an interesting sub-network of genes within that network, determine which functions are enriched in the sub-network, and iii given two networks, determine the functions for which the connectivity improves when we merge the second network into the first. Through these applications, we show that our approach is a natural alternative to network clustering algorithms. Conclusions We presented a novel approach to functional enrichment that takes into account the pairwise relationships among genes annotated by a particular function. Each of the three applications discovers highly relevant functions. We used our methods to study biological data from three different organisms. Our results demonstrate the wide applicability of our methods. Our algorithms are

  2. Optimal design of permanent magnet flux switching generator for wind applications via artificial neural network and multi-objective particle swarm optimization hybrid approach

    International Nuclear Information System (INIS)

    Meo, Santolo; Zohoori, Alireza; Vahedi, Abolfazl

    2016-01-01

    Highlights: • A new optimal design of flux switching permanent magnet generator is developed. • A prototype is employed to validate numerical data used for optimization. • A novel hybrid multi-objective particle swarm optimization approach is proposed. • Optimization targets are weight, cost, voltage and its total harmonic distortion. • The hybrid approach preference is proved compared with other optimization methods. - Abstract: In this paper a new hybrid approach obtained combining a multi-objective particle swarm optimization and artificial neural network is proposed for the design optimization of a direct-drive permanent magnet flux switching generators for low power wind applications. The targets of the proposed multi-objective optimization are to reduce the costs and weight of the machine while maximizing the amplitude of the induced voltage as well as minimizing its total harmonic distortion. The permanent magnet width, the stator and rotor tooth width, the rotor teeth number and stator pole number of the machine define the search space for the optimization problem. Four supervised artificial neural networks are designed for modeling the complex relationships among the weight, the cost, the amplitude and the total harmonic distortion of the output voltage respect to the quantities of the search space. Finite element analysis is adopted to generate training dataset for the artificial neural networks. Finite element analysis based model is verified by experimental results with a 1.5 kW permanent magnet flux switching generator prototype suitable for renewable energy applications, having 6/19 stator poles/rotor teeth. Finally the effectiveness of the proposed hybrid procedure is compared with the results given by conventional multi-objective optimization algorithms. The obtained results show the soundness of the proposed multi objective optimization technique and its feasibility to be adopted as suitable methodology for optimal design of permanent

  3. Evaluation of the threshold trimming method for micro inertial fluidic switch based on electrowetting technology

    Directory of Open Access Journals (Sweden)

    Tingting Liu

    2014-03-01

    Full Text Available The switch based on electrowetting technology has the advantages of no moving part, low contact resistance, long life and adjustable acceleration threshold. The acceleration threshold of switch can be fine-tuned by adjusting the applied voltage. This paper is focused on the electrowetting properties of switch and the influence of microchannel structural parameters, applied voltage and droplet volume on acceleration threshold. In the presence of process errors of micro inertial fluidic switch and measuring errors of droplet volume, there is a deviation between test acceleration threshold and target acceleration threshold. Considering the process errors and measuring errors, worst-case analysis is used to analyze the influence of parameter tolerance on the acceleration threshold. Under worst-case condition the total acceleration threshold tolerance caused by various errors is 9.95%. The target acceleration threshold can be achieved by fine-tuning the applied voltage. The acceleration threshold trimming method of micro inertial fluidic switch is verified.

  4. Investigations and Simulations of All optical Switches in linear state Based on Photonic Crystal Directional Coupler

    Directory of Open Access Journals (Sweden)

    S. Maktoobi

    2014-10-01

    Full Text Available Switching is a principle process in digital computers and signal processing systems. The growth of optical signal processing systems, draws particular attention to design of ultra-fast optical switches. In this paper, All Optical Switches in linear state Based On photonic crystal Directional coupler is analyzed and simulated. Among different methods, the finite difference time domain method (FDTD is a preferable method and is used. We have studied the application of photonic crystal lattices, the physics of optical switching and photonic crystal Directional coupler. In this paper, Electric field intensity and the power output that are two factors to improve the switching performance and the device efficiency are investigated and simulated. All simulations are performed by COMSOL software.

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

    International Nuclear Information System (INIS)

    Tartan, Chloe C.; Salter, Patrick S.; Booth, Martin J.; Morris, Stephen M.; Elston, Steve J.

    2016-01-01

    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.

  6. 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.

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

    Science.gov (United States)

    Tartan, Chloe C.; Salter, Patrick S.; Booth, Martin J.; Morris, Stephen M.; Elston, Steve J.

    2016-05-01

    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.

  8. Configurable Resistive Switching between Memory and Threshold Characteristics for Protein-Based Devices

    KAUST Repository

    Wang, Hong; Du, Yuanmin; Li, Yingtao; Zhu, Bowen; Leow, Wan Ru; Li, Yuangang; Pan, Jisheng; Wu, Tao; Chen, Xiaodong

    2015-01-01

    The employ of natural biomaterials as the basic building blocks of electronic devices is of growing interest for biocompatible and green electronics. Here, resistive switching (RS) devices based on naturally silk protein with configurable

  9. Near-optimality of special periodic protocols for fluid models of single server switched networks with switchover times

    Science.gov (United States)

    Matveev, A. S.; Ishchenko, R.

    2017-11-01

    We consider a generic deterministic time-invariant fluid model of a single server switched network, which consists of finitely many infinite size buffers (queues) and receives constant rate inflows of jobs from the outside. Any flow undergoes a multi-phase service, entering a specific buffer after every phase, and ultimately leaves the network; the route of the flow over the buffers is pre-specified, and flows may merge inside the network. They share a common source of service, which can serve at most one buffer at a time and has to switch among buffers from time to time; any switch consumes a nonzero switchover period. With respect to the long-run maximal scaled wip (work in progress) performance metric, near-optimality of periodic scheduling and service protocols is established: the deepest optimum (that is over all feasible processes in the network, irrespective of the initial state) is furnished by such a protocol up to as small error as desired. Moreover, this can be achieved with a special periodic protocol introduced in the paper. It is also shown that the exhaustive policy is optimal for any buffer whose service at the maximal rate does not cause growth of the scaled wip.

  10. Resistive switching in microscale anodic titanium dioxide-based memristors

    Science.gov (United States)

    Aglieri, V.; Zaffora, A.; Lullo, G.; Santamaria, M.; Di Franco, F.; Lo Cicero, U.; Mosca, M.; Macaluso, R.

    2018-01-01

    The potentiality of anodic TiO2 as an oxide material for the realization of resistive switching memory cells has been explored in this paper. Cu/anodic-TiO2/Ti memristors of different sizes, ranging from 1 × 1 μm2 to 10 × 10 μm2 have been fabricated and characterized. The oxide films were grown by anodizing Ti films, using three different process conditions. Measured IV curves have shown similar asymmetric bipolar hysteresis behaviors in all the tested devices, with a gradual switching from the high resistance state to the low resistance state and vice versa, and a ROFF/RON ratio of 80 for the thickest oxide film devices.

  11. Ultra-Fast All-Optical Self-Aware Protection Switching Based on a Bistable Laser Diode

    DEFF Research Database (Denmark)

    An, Yi; Vukovic, Dragana; Lorences Riesgo, Abel

    2014-01-01

    We propose a novel concept of all-optical protection switching with link failure automatic awareness based on AOWFF. The scheme is experimentally demonstrated using a single MG-Y laser diode with a record switching time ~200 ps....

  12. Dual-functional Memory and Threshold Resistive Switching Based on the Push-Pull Mechanism of Oxygen Ions

    KAUST Repository

    Huang, Yi-Jen; Chao, Shih-Chun; Lien, Der-Hsien; Wen, Cheng-Yen; He, Jr-Hau; Lee, Si-Chen

    2016-01-01

    The combination of nonvolatile memory switching and volatile threshold switching functions of transition metal oxides in crossbar memory arrays is of great potential for replacing charge-based flash memory in very-large-scale integration. Here, we

  13. Paper-based synthetic gene networks.

    Science.gov (United States)

    Pardee, Keith; Green, Alexander A; Ferrante, Tom; Cameron, D Ewen; DaleyKeyser, Ajay; Yin, Peng; Collins, James J

    2014-11-06

    Synthetic gene networks have wide-ranging uses in reprogramming and rewiring organisms. To date, there has not been a way to harness the vast potential of these networks beyond the constraints of a laboratory or in vivo environment. Here, we present an in vitro paper-based platform that provides an alternate, versatile venue for synthetic biologists to operate and a much-needed medium for the safe deployment of engineered gene circuits beyond the lab. Commercially available cell-free systems are freeze dried onto paper, enabling the inexpensive, sterile, and abiotic distribution of synthetic-biology-based technologies for the clinic, global health, industry, research, and education. For field use, we create circuits with colorimetric outputs for detection by eye and fabricate a low-cost, electronic optical interface. We demonstrate this technology with small-molecule and RNA actuation of genetic switches, rapid prototyping of complex gene circuits, and programmable in vitro diagnostics, including glucose sensors and strain-specific Ebola virus sensors.

  14. Paper-based Synthetic Gene Networks

    Science.gov (United States)

    Pardee, Keith; Green, Alexander A.; Ferrante, Tom; Cameron, D. Ewen; DaleyKeyser, Ajay; Yin, Peng; Collins, James J.

    2014-01-01

    Synthetic gene networks have wide-ranging uses in reprogramming and rewiring organisms. To date, there has not been a way to harness the vast potential of these networks beyond the constraints of a laboratory or in vivo environment. Here, we present an in vitro paper-based platform that provides a new venue for synthetic biologists to operate, and a much-needed medium for the safe deployment of engineered gene circuits beyond the lab. Commercially available cell-free systems are freeze-dried onto paper, enabling the inexpensive, sterile and abiotic distribution of synthetic biology-based technologies for the clinic, global health, industry, research and education. For field use, we create circuits with colorimetric outputs for detection by eye, and fabricate a low-cost, electronic optical interface. We demonstrate this technology with small molecule and RNA actuation of genetic switches, rapid prototyping of complex gene circuits, and programmable in vitro diagnostics, including glucose sensors and strain-specific Ebola virus sensors. PMID:25417167

  15. Friendship-based partner switching promotes cooperation in heterogeneous populations

    Science.gov (United States)

    Chen, Wei; Wu, Te; Li, Zhiwu; Wang, Long

    2016-02-01

    The forming of human social ties tends to be with similar individuals. This study concentrates on the emergence of cooperation among heterogeneous populations. A simple model is proposed by considering the impact of interplay between the evolution of strategies and that of social partnerships on cooperation dynamics. Whenever two individuals acquire the rewards by playing prisoner's dilemma game with each other, the friendship (friendship is quantified as the weight of a link) between the two individuals deepens. Individuals can switch off the social ties with the partners who are unfriendly and rewire to similar new ones. Under this partner switching mechanism, population structure is divided into several groups and cooperation can prevail. It is observed that the frequent tendency of partner switching can lead to the enhancement of cooperative behavior under the enormous temptation to defect. Moreover, the influence of discounting the relationship between different individuals is also investigated. Meanwhile, the cooperation prevails when the adjustment of friendships mainly depends on the incomes of selected individuals rather than that of their partners. Finally, it is found that too similar population fail to maximize the cooperation and there exists a moderate similarity that can optimize cooperation.

  16. 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

    2017-09-29

    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  μs.

  17. Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

    KAUST Repository

    Bouchaala, Adam M.

    2016-05-25

    The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

  18. Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

    KAUST Repository

    Bouchaala, Adam M.; Jaber, Nizar; Yassine, Omar; Shekhah, Osama; Chernikova, Valeriya; Eddaoudi, Mohamed; Younis, Mohammad I.

    2016-01-01

    The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

  19. Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

    Directory of Open Access Journals (Sweden)

    Adam Bouchaala

    2016-05-01

    Full Text Available The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF, namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

  20. Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

    Science.gov (United States)

    Bouchaala, Adam; Jaber, Nizar; Yassine, Omar; Shekhah, Osama; Chernikova, Valeriya; Eddaoudi, Mohamed; Younis, Mohammad I.

    2016-01-01

    The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming. PMID:27231914

  1. Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection.

    Science.gov (United States)

    Bouchaala, Adam; Jaber, Nizar; Yassine, Omar; Shekhah, Osama; Chernikova, Valeriya; Eddaoudi, Mohamed; Younis, Mohammad I

    2016-05-25

    The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

  2. A Secure Network Coding Based on Broadcast Encryption in SDN

    Directory of Open Access Journals (Sweden)

    Yue Chen

    2016-01-01

    Full Text Available By allowing intermediate nodes to encode the received packets before sending them out, network coding improves the capacity and robustness of multicast applications. But it is vulnerable to the pollution attacks. Some signature schemes were proposed to thwart such attacks, but most of them need to be homomorphic that the keys cannot be generated and managed easily. In this paper, we propose a novel fast and secure switch network coding multicast (SSNC on the software defined networks (SDN. In our scheme, the complicated secure multicast management was separated from the fast data transmission based on the SDN. Multiple multicasts will be aggregated to one multicast group according to the requirements of services and the network status. Then, the controller will route aggregated multicast group with network coding; only the trusted switch will be allowed to join the network coding by using broadcast encryption. The proposed scheme can use the traditional cryptography without homomorphy, which greatly reduces the complexity of the computation and improves the efficiency of transmission.

  3. Pulse power requirements for large aperture optical switches based on plasma electrode Pockels cells

    International Nuclear Information System (INIS)

    Rhodes, M.A.; Taylor, J.

    1992-06-01

    We discuss very large-aperture optical switches (greater than 30 x 30 cm) as an enabling technology for inertial confinement fusion drivers based on multipass laser amplifiers. Large-scale laser fusion drivers such as the Nova laser have been based on single-pass amplifier designs in part because of the unavailability of a suitable large-aperture switch. We are developing an optical switch based on a Pockels cell employing plasma-electrodes. A plasma-electrode Pockels cell (PEPC) is a longitudinal-mode Pockels cell in which a plasma discharge is formed on each side of an electro-optic crystal (typically KDP or deuterated KDP, often designated KD*P). The plasmas formed on either side of the crystal act as transparent electrodes for a switching-pulse and are intended to allow uniform charging of the entire crystal. The switching-pulse is a nominally rectangular high-voltage pulse equal to the half-wave voltage V x ( 8 kV for KD*P or 17 kV for KDP) and is applied across the crystal via the plasma-electrodes. When the crystal is charged to V x , the polarization of an incoming, linearly polarized, laser beam is rotated by 90 degree. When used in conjunction with an appropriate, passive polarizer, an optical switch is thus realized. A switch with a clear aperture of 37 x 37 cm is now in construction for the Beamlet laser which will serve as a test bed for this switch as well as other technologies required for an advanced NOVA laser design. In this paper, we discuss the unique power electronics requirements of PEPC optical switches

  4. Electrical Switching in Thin Film Structures Based on Transition Metal Oxides

    Directory of Open Access Journals (Sweden)

    A. Pergament

    2015-01-01

    Full Text Available Electrical switching, manifesting itself in the nonlinear current-voltage characteristics with S- and N-type NDR (negative differential resistance, is inherent in a variety of materials, in particular, transition metal oxides. Although this phenomenon has been known for a long time, recent suggestions to use oxide-based switching elements as neuristor synapses and relaxation-oscillation circuit components have resumed the interest in this area. In the present review, we describe the experimental facts and theoretical models, mainly on the basis of the Mott transition in vanadium dioxide as a model object, of the switching effect with special emphasis on the emerging applied potentialities for oxide electronics.

  5. First-principles study of the electronic transport properties of the anthraquinone-based molecular switch

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, P., E-mail: ss_zhaop@ujn.edu.c [School of Science, University of Jinan, Jinan 250022 (China); Liu, D.S. [School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Department of Physics, Jining University, Qufu 273155 (China); Wang, P.J.; Zhang, Z. [School of Science, University of Jinan, Jinan 250022 (China); Fang, C.F.; Ji, G.M. [School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China)

    2011-02-15

    By applying non-equilibrium Green's function (NEGF) formalism combined with first-principles density functional theory (DFT), we have investigated the electronic transport properties of the anthraquinone-based molecular switch. The molecule that comprises the switch can be converted between the hydroquinone (HQ) and anthraquinone (AQ) forms via redox reactions. The transmission spectra of these two forms are remarkably distinctive. Our results show that the current through the HQ form is significantly larger than that through the AQ form, which suggests that this system has attractive potential application in future molecular switch technology.

  6. First-principles study of the electronic transport properties of the anthraquinone-based molecular switch

    International Nuclear Information System (INIS)

    Zhao, P.; Liu, D.S.; Wang, P.J.; Zhang, Z.; Fang, C.F.; Ji, G.M.

    2011-01-01

    By applying non-equilibrium Green's function (NEGF) formalism combined with first-principles density functional theory (DFT), we have investigated the electronic transport properties of the anthraquinone-based molecular switch. The molecule that comprises the switch can be converted between the hydroquinone (HQ) and anthraquinone (AQ) forms via redox reactions. The transmission spectra of these two forms are remarkably distinctive. Our results show that the current through the HQ form is significantly larger than that through the AQ form, which suggests that this system has attractive potential application in future molecular switch technology.

  7. Switched Flip-Flop based Preprocessing Circuit for ISFETs

    Directory of Open Access Journals (Sweden)

    Martin Kollár

    2005-03-01

    Full Text Available In this paper, a preprocessing circuit for ISFETs (Ion-sensitive field-effecttransistors to measure hydrogen-ion concentration in electrolyte is presented. A modifiedflip-flop is the main part of the circuit. The modification consists in replacing the standardtransistors by ISFETs and periodically switching the supply voltage on and off.Concentration of hydrogen ions to be measured discontinues the flip-flop value symmetry,which means that by switching the supply voltage on the flip-flop goes to one of two stablestates, ‘one’ or ‘zero’. The recovery of the value symmetry can be achieved by changing abalanced voltage, which is incorporated to the flip-flop, to bring the flip-flop to a 50%position (probability of ‘one’ equals to probability of ‘zero’. Thus, the balanced voltagereflects the measured concentration of hydrogen ions. Its magnitude is set automatically byusing a feedback circuit whose input is connected to the flip-flop output. The preprocessingcircuit, as the whole, is the well-known δ modulator in which the switched flip-flop servesas a comparator and a sampling circuit. The advantages of this approach in comparison tothose of standard approaches are discussed. Finally, theoretical results are verified bysimulations with TSPICE and a good agreement is reported.

  8. All-optical header recognizer for optical packet switched networks : exploiting nonlinear gain and index dynamics in semiconductor optical amplifiers for low power operation and photonic integration device

    NARCIS (Netherlands)

    Calabretta, N.; Dorren, H.J.S.

    2009-01-01

    The increase of the internet traffic leads to future optical networks requiring tens of Tb/s of capacity. Current electronic circuit switches are limited by the scalability of the electronic switching fabrics, power consumption and dissipation in the opto- electronic conversion. All-optical packet

  9. Organic-based molecular switches for molecular electronics.

    Science.gov (United States)

    Fuentes, Noelia; Martín-Lasanta, Ana; Alvarez de Cienfuegos, Luis; Ribagorda, Maria; Parra, Andres; Cuerva, Juan M

    2011-10-05

    In a general sense, molecular electronics (ME) is the branch of nanotechnology which studies the application of molecular building blocks for the fabrication of electronic components. Among the different types of molecules, organic compounds have been revealed as promising candidates for ME, due to the easy access, great structural diversity and suitable electronic and mechanical properties. Thanks to these useful capabilities, organic molecules have been used to emulate electronic devices at the nanoscopic scale. In this feature article, we present the diverse strategies used to develop organic switches towards ME with special attention to non-volatile systems.

  10. Zero Trust Cloud Networks using Transport Access Control and High Availability Optical Bypass Switching

    Directory of Open Access Journals (Sweden)

    Casimer DeCusatis

    2017-04-01

    Full Text Available Cyberinfrastructure is undergoing a radical transformation as traditional enterprise and cloud computing environments hosting dynamic, mobile workloads replace telecommunication data centers. Traditional data center security best practices involving network segmentation are not well suited to these new environments. We discuss a novel network architecture, which enables an explicit zero trust approach, based on a steganographic overlay, which embeds authentication tokens in the TCP packet request, and first-packet authentication. Experimental demonstration of this approach is provided in both an enterprise-class server and cloud computing data center environment.

  11. Reversible light-controlled conductance switching of azobenzene-based metal/polymer nanocomposites

    International Nuclear Information System (INIS)

    Pakula, Christina; Zaporojtchenko, Vladimir; Strunskus, Thomas; Faupel, Franz; Zargarani, Dordaneh; Herges, Rainer

    2010-01-01

    We present a new concept of light-controlled conductance switching based on metal/polymer nanocomposites with dissolved chromophores that do not have intrinsic current switching ability. Photoswitchable metal/PMMA nanocomposites were prepared by physical vapor deposition of Au and Pt clusters, respectively, onto spin-coated thin poly(methylmethacrylate) films doped with azo-dye molecules. High dye concentrations were achieved by functionalizing the azo groups with tails and branches, thus enhancing solubility. The composites show completely reversible optical switching of the absorption bands upon alternating irradiation with UV and blue light. We also demonstrate reversible light-controlled conductance switching. This is attributed to changes in the metal cluster separation upon isomerization based on model experiments where analogous conductance changes were induced by swelling of the composite films in organic vapors and by tensile stress.

  12. Migration of interfacial oxygen ions modulated resistive switching in oxide-based memory devices

    Science.gov (United States)

    Chen, C.; Gao, S.; Zeng, F.; Tang, G. S.; Li, S. Z.; Song, C.; Fu, H. D.; Pan, F.

    2013-07-01

    Oxides-based resistive switching memory induced by oxygen ions migration is attractive for future nonvolatile memories. Numerous works had focused their attentions on the sandwiched oxide materials for depressing the characteristic variations, but the comprehensive studies of the dependence of electrodes on the migration behavior of oxygen ions are overshadowed. Here, we investigated the interaction of various metals (Ni, Co, Al, Ti, Zr, and Hf) with oxygen atoms at the metal/Ta2O5 interface under electric stress and explored the effect of top electrode on the characteristic variations of Ta2O5-based memory device. It is demonstrated that chemically inert electrodes (Ni and Co) lead to the scattering switching characteristics and destructive gas bubbles, while the highly chemically active metals (Hf and Zr) formed a thick and dense interfacial intermediate oxide layer at the metal/Ta2O5 interface, which also degraded the resistive switching behavior. The relatively chemically active metals (Al and Ti) can absorb oxygen ions from the Ta2O5 film and avoid forming the problematic interfacial layer, which is benefit to the formation of oxygen vacancies composed conduction filaments in Ta2O5 film thus exhibit the minimum variations of switching characteristics. The clarification of oxygen ions migration behavior at the interface can lead further optimization of resistive switching performance in Ta2O5-based memory device and guide the rule of electrode selection for other oxide-based resistive switching memories.

  13. All-optical switching based on optical fibre long period gratings modified bacteriorhodopsin

    Science.gov (United States)

    Korposh, S.; James, S.; Partridge, M.; Sichka, M.; Tatam, R.

    2018-05-01

    All-optical switching using an optical fibre long-period gating (LPG) modified with bacteriorhodopsin (bR) is demonstrated. The switching process is based on the photo-induced RI change of bR, which in turn changes the phase matching conditions of the mode coupling by the LPG, leading to modulation of the propagating light. The effect was studied with an LPG immersed into a bR solution and with LPGs coated with the bR films, deposited onto the LPGs using the layer-by-layer electrostatic self-assembly (LbL) method. The dependence of the all-optical switching efficiency upon the concentration of the bR solution and on the grating period of the LPG was also studied. In addition, an in-fibre Mach-Zehnder interferometer (MZI) composed of a cascaded LPG pair separated by 30 mm and modified with bR was used to enhance the wavelength range of all-optical switching. The switching wavelength is determined by the grating period of the LPG. Switching efficiencies of 16% and 35% were observed when an LPG and an MZI were immersed into bR solutions, respectively. The switching time for devices coated with bR-films was within 1 s, 10 times faster than that observed for devices immersed into bR solution.

  14. LMI-based adaptive reliable H∞ static output feedback control against switched actuator failures

    Science.gov (United States)

    An, Liwei; Zhai, Ding; Dong, Jiuxiang; Zhang, Qingling

    2017-08-01

    This paper investigates the H∞ static output feedback (SOF) control problem for switched linear system under arbitrary switching, where the actuator failure models are considered to depend on switching signal. An active reliable control scheme is developed by combination of linear matrix inequality (LMI) method and adaptive mechanism. First, by exploiting variable substitution and Finsler's lemma, new LMI conditions are given for designing the SOF controller. Compared to the existing results, the proposed design conditions are more relaxed and can be applied to a wider class of no-fault linear systems. Then a novel adaptive mechanism is established, where the inverses of switched failure scaling factors are estimated online to accommodate the effects of actuator failure on systems. Two main difficulties arise: first is how to design the switched adaptive laws to prevent the missing of estimating information due to switching; second is how to construct a common Lyapunov function based on a switched estimate error term. It is shown that the new method can give less conservative results than that for the traditional control design with fixed gain matrices. Finally, simulation results on the HiMAT aircraft are given to show the effectiveness of the proposed approaches.

  15. Redox switching and oxygen evolution at oxidized metal and metal oxide electrodes: iron in base.

    Science.gov (United States)

    Lyons, Michael E G; Doyle, Richard L; Brandon, Michael P

    2011-12-28

    Outstanding issues regarding the film formation, redox switching characteristics and the oxygen evolution reaction (OER) electrocatalytic behaviour of multicycled iron oxyhydroxide films in aqueous alkaline solution have been revisited. The oxide is grown using a repetitive potential multicycling technique, and the mechanism of the latter hydrous oxide formation process has been discussed. A duplex layer model of the oxide/solution interphase region is proposed. The acid/base behaviour of the hydrous oxide and the microdispersed nature of the latter material has been emphasised. The hydrous oxide is considered as a porous assembly of interlinked octahedrally coordinated anionic metal oxyhydroxide surfaquo complexes which form an open network structure. The latter contains considerable quantities of water molecules which facilitate hydroxide ion discharge at the metal site during active oxygen evolution, and also charge compensating cations. The dynamics of redox switching has been quantified via analysis of the cyclic voltammetry response as a function of potential sweep rate using the Laviron-Aoki electron hopping diffusion model by analogy with redox polymer modified electrodes. Steady state Tafel plot analysis has been used to elucidate the kinetics and mechanism of oxygen evolution. Tafel slope values of ca. 60 mV dec(-1) and ca. 120 mV dec(-1) are found at low and high overpotentials respectively, whereas the reaction order with respect to hydroxide ion activity changes from ca. 3/2 to ca. 1 as the potential is increased. These observations are rationalised in terms of a kinetic scheme involving Temkin adsorption and the rate determining formation of a physisorbed hydrogen peroxide intermediate on the oxide surface. The dual Tafel slope behaviour is ascribed to the potential dependence of the surface coverage of adsorbed intermediates.

  16. Optimal Control of Micro Grid Operation Mode Seamless Switching Based on Radau Allocation Method

    Science.gov (United States)

    Chen, Xiaomin; Wang, Gang

    2017-05-01

    The seamless switching process of micro grid operation mode directly affects the safety and stability of its operation. According to the switching process from island mode to grid-connected mode of micro grid, we establish a dynamic optimization model based on two grid-connected inverters. We use Radau allocation method to discretize the model, and use Newton iteration method to obtain the optimal solution. Finally, we implement the optimization mode in MATLAB and get the optimal control trajectory of the inverters.

  17. Origin of magnetic switching field distribution in bit patterned media based on pre-patterned substrates

    OpenAIRE

    Pfau , B; Günther , C.M.; Guehrs , E; Hauet , Thomas; Yang , H; Vinh , L.; Xu , X; Yaney , D; Rick , R; Eisebitt , S; Hellwig , O

    2011-01-01

    International audience; Using a combination of synchrotron radiation based magnetic imaging and high-resolution transmission electron microscopy we reveal systematic correlations between the magnetic switching field and the internal nanoscale structure of individual islands in bit patterned media fabricated by Co/Pd-multilayer deposition onto pre-patterned substrates. We find that misaligned grains at the island periphery are a common feature independent of the island switching field, while i...

  18. REDISTRIBUTION OF BASE STATIONS LOAD IN MOBILE COMMUNICATION NETWORKS

    Directory of Open Access Journals (Sweden)

    Igor Ruban

    2017-09-01

    Full Text Available The subject matter of the article is the processes of load distribution in mobile communication networks. The object of research is the handover. The goal is to develop a method for redistributing the load between neighboring areas for mobile nodes. The considered base stations are supposed to have the signal-to-noise ratios that are equal or close. The methods that are used: methods of system analysis, methods of digital signal processing. The following results are obtained. The method that allows mobile nodes, whose signal-to-noise ratios are equal or close, to switch to a less loaded base station. This method allows the base station to launch the handover process enabling more even distribution of the load from mobile nodes among neighboring base stations in wireless and mobile networks. In the suggested modification of the method, the function assessing the bandwidth of the uplink channel is added to the base stations, as well a threshold value for using its bandwidth. Thus, when the current value of bandwidth reaches the threshold, the base station starts sending out a message to all mobile nodes and verifies free neighboring areas for switching over mobile nodes. If there are adjacent areas with a lower load, the base station notifies all potential candidates about the necessity of their switching over. The handover process is launched when the available bandwidth of the base station decreases below a certain threshold. Therefore, it is possible to optimize the operation of the WiMAX network with respect to the criterion of the total bandwidth capacity of the base stations. Besides, the results of the comparative analysis of the handover process in networks based on the WiMAX technology that are obtained using the OpNet simulation environment are presented. Conclusions.The suggested approach can be used to improve the basic software of mobile communication networks. When moving a node from one area to another one in access servers, the

  19. 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

    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 ...

  20. Ferroelectric domain switching dynamics and memristive behaviors in BiFeO3-based magnetoelectric heterojunctions

    Science.gov (United States)

    Huang, Weichuan; Liu, Yukuai; Luo, Zhen; Hou, Chuangming; Zhao, Wenbo; Yin, Yuewei; Li, Xiaoguang

    2018-06-01

    The ferroelectric domain reversal dynamics and the corresponding resistance switching as well as the memristive behaviors in epitaxial BiFeO3 (BFO, ~150 nm) based multiferroic heterojunctions were systematically investigated. The ferroelectric domain reversal dynamics could be described by the nucleation-limited-switching model with the Lorentzian distribution of logarithmic domain-switching times. By engineering the domain states, multi and even continuously tunable resistances states, i.e. memristive states, could be non-volatilely achieved. The resistance switching speed can be as fast as 30 ns in the BFO-based multiferroic heterojunctions with a write voltage of ~20 V. By reducing the thickness of BFO, the La0.6Sr0.4MnO3/BFO (~5 nm)/La0.6Sr0.4MnO3 multiferroic tunnel junction (MFTJ) shows an even a quicker switching speed (20 ns) with a much lower operation voltage (~4 V). Importantly, the MFTJ exhibits a tunable interfacial magnetoelectric coupling related to the ferroelectric domain switching dynamics. These findings enrich the potential applications of multiferroic BFO based devices in high-speed, low-power, and high-density memories as well as future neuromorphic computational architectures.

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

    Science.gov (United States)

    Cui, Zhenqian

    1999-01-01

    In this thesis, we analyze various factors that affect quality of service (QoS) communication in high-speed, packet-switching sub-networks. We hypothesize that sub-network-wide bandwidth reservation and guaranteed CPU processing power at endpoint systems for handling data traffic are indispensable to achieving hard end-to-end quality of service. Different bandwidth reservation strategies, traffic characterization schemes, and scheduling algorithms affect the network resources and CPU usage as well as the extent that QoS can be achieved. In order to analyze those factors, we design and implement a communication layer. Our experimental analysis supports our research hypothesis. The Resource ReSerVation Protocol (RSVP) is designed to realize resource reservation. Our analysis of RSVP shows that using RSVP solely is insufficient to provide hard end-to-end quality of service in a high-speed sub-network. Analysis of the IEEE 802.lp protocol also supports the research hypothesis.

  2. Coupling between feedback loops in autoregulatory networks affects bistability range, open-loop gain and switching times

    International Nuclear Information System (INIS)

    Tiwari, Abhinav; Igoshin, Oleg A

    2012-01-01

    Biochemical regulatory networks governing diverse cellular processes such as stress-response, differentiation and cell cycle often contain coupled feedback loops. We aim at understanding how features of feedback architecture, such as the number of loops, the sign of the loops and the type of their coupling, affect network dynamical performance. Specifically, we investigate how bistability range, maximum open-loop gain and switching times of a network with transcriptional positive feedback are affected by additive or multiplicative coupling with another positive- or negative-feedback loop. We show that a network's bistability range is positively correlated with its maximum open-loop gain and that both quantities depend on the sign of the feedback loops and the type of feedback coupling. Moreover, we find that the addition of positive feedback could decrease the bistability range if we control the basal level in the signal-response curves of the two systems. Furthermore, the addition of negative feedback has the capacity to increase the bistability range if its dissociation constant is much lower than that of the positive feedback. We also find that the addition of a positive feedback to a bistable network increases the robustness of its bistability range, whereas the addition of a negative feedback decreases it. Finally, we show that the switching time for a transition from a high to a low steady state increases with the effective fold change in gene regulation. In summary, we show that the effect of coupled feedback loops on the bistability range and switching times depends on the underlying mechanistic details. (paper)

  3. Microcontroller based PWM controlled four switch three phase inverter fed induction motor drive

    Directory of Open Access Journals (Sweden)

    Mohanty Kant Nalin

    2010-01-01

    Full Text Available This paper presents PIC microcontroller based PWM inverter controlled four switch three phase inverter (FSTPI fed Induction Motor drive. The advantage of this inverter that uses of 4 switches instead of conventional 6 switches is lesser switching losses, lower electromagnetic interference (EMI, less complexity of control algorithms and reduced interface circuits. Simulation and experimental work are carried out and results presented to demonstrate the feasibility of the proposed approach. Simulation is carried out using MATLAB SIMULINK and in the experimental work a prototype model is built to verify the simulation results. PIC microcontroller (PIC 16F877A is used to generate the PWM pulses for FSTPI to drive the 0.5 hp 3-phase Induction Motor.

  4. Ultra Low Voltage Class AB Switched Current Memory Cells Based on Floating Gate Transistors

    DEFF Research Database (Denmark)

    Mucha, Igor

    1999-01-01

    current memory cells were designed using a CMOS process with threshold voltages V-T0n = \\V-T0p\\ = 0.9 V for the n- and p-channel devices. Both hand calculations and PSPICE simulations showed that the designed example switched current memory cell allowed a maximum signal range better than +/-18 mu......A proposal for a class AB switched current memory cell, suitable for ultra-low-voltage applications is presented. The proposal employs transistors with floating gates, allowing to build analog building blocks for ultralow supply voltage operation also in CMOS processes with high threshold voltages....... This paper presents the theoretical basis for the design of "floating-gate'' switched current memory cells by giving a detailed description and analysis of the most important impacts degrading the performance of the cells. To support the theoretical assumptions circuits based on "floating-gate'' switched...

  5. Micro optical fiber display switch based on the magnetohydrodynamic (MHD) principle

    Science.gov (United States)

    Lian, Kun; Heng, Khee-Hang

    2001-09-01

    This paper reports on a research effort to design, microfabricate and test an optical fiber display switch based on magneto hydrodynamic (MHD) principal. The switch is driven by the Lorentz force and can be used to turn on/off the light. The SU-8 photoresist and UV light source were used for prototype fabrication in order to lower the cost. With a magnetic field supplied by an external permanent magnet, and a plus electrical current supplied across the two inert sidewall electrodes, the distributed body force generated will produce a pressure difference on the fluid mercury in the switch chamber. By change the direction of current flow, the mercury can turn on or cut off the light pass in less than 10 ms. The major advantages of a MHD-based micro-switch are that it does not contain any solid moving parts and power consumption is much smaller comparing to the relay type switches. This switch can be manufactured by molding gin batch production and may have potential applications in extremely bright traffic control,, high intensity advertising display, and communication.

  6. Adaptation in constitutional dynamic libraries and networks, switching between orthogonal metalloselection and photoselection processes.

    Science.gov (United States)

    Vantomme, Ghislaine; Jiang, Shimei; Lehn, Jean-Marie

    2014-07-02

    Constitutional dynamic libraries of hydrazones (a)A(b)B and acylhydrazones (a)A(c)C undergo reorganization and adaptation in response to a chemical effector (metal cations) or a physical stimulus (light). The set of hydrazones [(1)A(1)B, (1)A(2)B, (2)A(1)B, (2)A(2)B] undergoes metalloselection on addition of zinc cations which drive the amplification of Zn((1)A(2)B)2 by selection of the fittest component (1)A(2)B. The set of acylhydrazones [E-(1)A(1)C, (1)A(2)C, (2)A(1)C, (2)A(2)C] undergoes photoselection by irradiation of the system, which causes photoisomerization of E-(1)A(1)C into Z-(1)A(1)C with amplification of the latter. The set of acyl hydrazones [E-(1)A(1)C, (1)A(3)C, (2)A(1)C, (2)A(3)C] undergoes a dual adaptation via component exchange and selection in response to two orthogonal external agents: a chemical effector, metal cations, and a physical stimulus, light irradiation. Metalloselection takes place on addition of zinc cations which drive the amplification of Zn((1)A(3)C)2 by selection of the fittest constituent (1)A(3)C. Photoselection is obtained on irradiation of the acylhydrazones that leads to photoisomerization from E-(1)A(1)C to Z-(1)A(1)C configuration with amplification of the latter. These changes may be represented by square constitutional dynamic networks that display up-regulation of the pairs of agonists ((1)A(2)B, (2)A(1)B), (Z-(1)A(1)C, (2)A(2)C), ((1)A(3)C, (2)A(1)C), (Z-(1)A(1)C, (2)A(3)C) and the simultaneous down-regulation of the pairs of antagonists ((1)A(1)B, (2)A(2)B), ((1)A(2)C, (2)A(1)C), (E-(1)A(1)C, (2)A(3)C), ((1)A(3)C, (2)A(1)C). The orthogonal dual adaptation undergone by the set of acylhydrazones amounts to a network switching process.

  7. Path connectivity based spectral defragmentation in flexible bandwidth networks.

    Science.gov (United States)

    Wang, Ying; Zhang, Jie; Zhao, Yongli; Zhang, Jiawei; Zhao, Jie; Wang, Xinbo; Gu, Wanyi

    2013-01-28

    Optical networks with flexible bandwidth provisioning have become a very promising networking architecture. It enables efficient resource utilization and supports heterogeneous bandwidth demands. In this paper, two novel spectrum defragmentation approaches, i.e. Maximum Path Connectivity (MPC) algorithm and Path Connectivity Triggering (PCT) algorithm, are proposed based on the notion of Path Connectivity, which is defined to represent the maximum variation of node switching ability along the path in flexible bandwidth networks. A cost-performance-ratio based profitability model is given to denote the prons and cons of spectrum defragmentation. We compare these two proposed algorithms with non-defragmentation algorithm in terms of blocking probability. Then we analyze the differences of defragmentation profitability between MPC and PCT algorithms.

  8. Host Event Based Network Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Jonathan Chugg

    2013-01-01

    The purpose of INL’s research on this project is to demonstrate the feasibility of a host event based network monitoring tool and the effects on host performance. Current host based network monitoring tools work on polling which can miss activity if it occurs between polls. Instead of polling, a tool could be developed that makes use of event APIs in the operating system to receive asynchronous notifications of network activity. Analysis and logging of these events will allow the tool to construct the complete real-time and historical network configuration of the host while the tool is running. This research focused on three major operating systems commonly used by SCADA systems: Linux, WindowsXP, and Windows7. Windows 7 offers two paths that have minimal impact on the system and should be seriously considered. First is the new Windows Event Logging API, and, second, Windows 7 offers the ALE API within WFP. Any future work should focus on these methods.

  9. An Adaptive Method for Switching between Pedestrian/Car Indoor Positioning Algorithms based on Multilayer Time Sequences

    Directory of Open Access Journals (Sweden)

    Zhining Gu

    2018-02-01

    Full Text Available Pedestrian dead reckoning (PDR positioning algorithms can be used to obtain a target’s location only for movement with step features and not for driving, for which the trilateral Bluetooth indoor positioning method can be used. In this study, to obtain the precise locations of different states (pedestrian/car using the corresponding positioning algorithms, we propose an adaptive method for switching between the PDR and car indoor positioning algorithms based on multilayer time sequences (MTSs. MTSs, which consider the behavior context, comprise two main aspects: filtering of noisy data in small-scale time sequences and using a state chain to reduce the time delay of algorithm switching in large-scale time sequences. The proposed method can be expected to realize the recognition of stationary, walking, driving, or other states; switch to the correct indoor positioning algorithm; and improve the accuracy of localization compared to using a single positioning algorithm. Our experiments show that the recognition of static, walking, driving, and other states improves by 5.5%, 45.47%, 26.23%, and 21% on average, respectively, compared with convolutional neural network (CNN method. The time delay decreases by approximately 0.5–8.5 s for the transition between states and by approximately 24 s for the entire process.

  10. An Adaptive Method for Switching between Pedestrian/Car Indoor Positioning Algorithms based on Multilayer Time Sequences.

    Science.gov (United States)

    Gu, Zhining; Guo, Wei; Li, Chaoyang; Zhu, Xinyan; Guo, Tao

    2018-02-27

    Pedestrian dead reckoning (PDR) positioning algorithms can be used to obtain a target's location only for movement with step features and not for driving, for which the trilateral Bluetooth indoor positioning method can be used. In this study, to obtain the precise locations of different states (pedestrian/car) using the corresponding positioning algorithms, we propose an adaptive method for switching between the PDR and car indoor positioning algorithms based on multilayer time sequences (MTSs). MTSs, which consider the behavior context, comprise two main aspects: filtering of noisy data in small-scale time sequences and using a state chain to reduce the time delay of algorithm switching in large-scale time sequences. The proposed method can be expected to realize the recognition of stationary, walking, driving, or other states; switch to the correct indoor positioning algorithm; and improve the accuracy of localization compared to using a single positioning algorithm. Our experiments show that the recognition of static, walking, driving, and other states improves by 5.5%, 45.47%, 26.23%, and 21% on average, respectively, compared with convolutional neural network (CNN) method. The time delay decreases by approximately 0.5-8.5 s for the transition between states and by approximately 24 s for the entire process.

  11. 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

  12. 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...

  13. Multistage switching hardware and software implementations for student experiment purpose

    Science.gov (United States)

    Sani, A.; Suherman

    2018-02-01

    Current communication and internet networks are underpinned by the switching technologies that interconnect one network to the others. Students’ understanding on networks rely on how they conver the theories. However, understanding theories without touching the reality may exert spots in the overall knowledge. This paper reports the progress of the multistage switching design and implementation for student laboratory activities. The hardware and software designs are based on three stages clos switching architecture with modular 2x2 switches, controlled by an arduino microcontroller. The designed modules can also be extended for batcher and bayan switch, and working on circuit and packet switching systems. The circuit analysis and simulation show that the blocking probability for each switch combinations can be obtained by generating random or patterned traffics. The mathematic model and simulation analysis shows 16.4% blocking probability differences as the traffic generation is uniform. The circuits design components and interfacing solution have been identified to allow next step implementation.

  14. Cross-Platform Android/iOS-Based Smart Switch Control Middleware in a Digital Home

    Directory of Open Access Journals (Sweden)

    Guo Jie

    2015-01-01

    Full Text Available With technological and economic development, people’s lives have been improved substantially, especially their home environments. One of the key aspects of these improvements is home intellectualization, whose core is the smart home control system. Furthermore, as smart phones have become increasingly popular, we can use them to control the home system through Wi-Fi, Bluetooth, and GSM. This means that control with phones is more convenient and fast and now becomes the primary terminal controller in the smart home. In this paper, we propose middleware for developing a cross-platform Android/iOS-based solution for smart switch control software, focus on the Wi-Fi based communication protocols between the cellphone and the smart switch, achieved a plugin-based smart switch function, defined and implemented the JavaScript interface, and then implemented the cross-platform Android/iOS-based smart switch control software; also the scenarios are illustrated. Finally, tests were performed after the completed realization of the smart switch control system.

  15. A low-latency optical switch architecture using integrated μm SOI-based contention resolution and switching

    Science.gov (United States)

    Mourgias-Alexandris, G.; Moralis-Pegios, M.; Terzenidis, N.; Cherchi, M.; Harjanne, M.; Aalto, T.; Vyrsokinos, K.; Pleros, N.

    2018-02-01

    The urgent need for high-bandwidth and high-port connectivity in Data Centers has boosted the deployment of optoelectronic packet switches towards bringing high data-rate optics closer to the ASIC, realizing optical transceiver functions directly at the ASIC package for high-rate, low-energy and low-latency interconnects. Even though optics can offer a broad range of low-energy integrated switch fabrics for replacing electronic switches and seamlessly interface with the optical I/Os, the use of energy- and latency-consuming electronic SerDes continues to be a necessity, mainly dictated by the absence of integrated and reliable optical buffering solutions. SerDes undertakes the role of optimally synergizing the lower-speed electronic buffers with the incoming and outgoing optical streams, suggesting that a SerDes-released chip-scale optical switch fabric can be only realized in case all necessary functions including contention resolution and switching can be implemented on a common photonic integration platform. In this paper, we demonstrate experimentally a hybrid Broadcast-and-Select (BS) / wavelength routed optical switch that performs both the optical buffering and switching functions with μm-scale Silicon-integrated building blocks. Optical buffering is carried out in a silicon-integrated variable delay line bank with a record-high on-chip delay/footprint efficiency of 2.6ns/mm2 and up to 17.2 nsec delay capability, while switching is executed via a BS design and a silicon-integrated echelle grating, assisted by SOA-MZI wavelength conversion stages and controlled by a FPGA header processing module. The switch has been experimentally validated in a 3x3 arrangement with 10Gb/s NRZ optical data packets, demonstrating error-free switching operation with a power penalty of <5dB.

  16. Reservation centre of Telecom I satellite French Telecommunication network offers a new service of switched digital circuit

    Science.gov (United States)

    Felix, J.

    The management center and new circuit switching services offered by the French Telecom I network are described. Attention is focused on business services. The satellite has a 125 Mbit/sec capability distributed over 5 frequency bands, yielding the equivalent of 1800 channels. Data are transmitted in digitized bursts with TDMA techniques. Besides the management center, Telecom I interfaces with 310 local network antennas with access managed by the center through a reservation service and protocol assignment. The center logs and supervises alarms and network events, monitors traffic, logs taxation charges and manages the man-machine dialog for TDMA and terrestrial operations. Time slots are arranged in terms of minimal 10 min segments. The reservations can be directly accessed by up to 1000 terminals. All traffic is handled on a call-by-call basis.

  17. Investigation of patterning effects in ultrafast SOA-based optical switches

    DEFF Research Database (Denmark)

    Xu, Jing; Zhang, Xinliang; Mørk, Jesper

    2010-01-01

    , has been proposed based on the idea of driving the SOA at two saturation extremes by two periodic pulse trains. The predictive power of the periodic method is verified by comparing its results with those obtained by using ordinary PRBS patterns. Finally, the effectiveness of the periodic method...... is exploited by analyzing in detail the performance properties of a specific type of switch over large parameter regions. Besides allowing an investigation of patterning effects, the periodic method also simultaneously provides such figures of merit as output power and pulsewidth....... that limits the ultimate speed at which SOA-based switches can be operated. In this paper, we investigate the patterning effects of SOA-based switches using a systematic approach. A simple condition for the lower bound limit of the bit pattern length that should be adopted in the performance evaluations...

  18. Polyaniline-based memristive microdevice with high switching rate and endurance

    Science.gov (United States)

    Lapkin, D. A.; Emelyanov, A. V.; Demin, V. A.; Erokhin, V. V.; Feigin, L. A.; Kashkarov, P. K.; Kovalchuk, M. V.

    2018-01-01

    Polyaniline (PANI) based memristive devices have emerged as promising candidates for hardware implementation of artificial synapses (the key components of neuromorphic systems) due to their high flexibility, low cost, solution processability, three-dimensional stacking capability, and biocompatibility. Here, we report on a way of the significant improvement of the switching rate and endurance of PANI-based memristive devices. The reduction of the PANI active channel dimension leads to the increase in the resistive switching rate by hundreds of times in comparison with the conventional one. The miniaturized memristive device was shown to be stable within at least 104 cyclic switching events between high- and low-conductive states with a retention time of at least 103 s. The obtained results make PANI-based memristive devices potentially widely applicable in neuromorphic systems.

  19. ADAPTIVE GOSSIP BASED PROTOCOL FOR ENERGY EFFICIENT MOBILE ADHOC NETWORK

    Directory of Open Access Journals (Sweden)

    S. Rajeswari

    2012-03-01

    Full Text Available In Gossip Sleep Protocol, network performance is enhanced based on energy resource. But energy conservation is achieved with the reduced throughput. In this paper, it has been proposed a new Protocol for Mobile Ad hoc Network to achieve reliability with energy conservation. Based on the probability (p values, the value of sleep nodes is fixed initially. The probability value can be adaptively adjusted by Remote Activated Switch during the transmission process. The adaptiveness of gossiping probability is determined by the Packet Delivery Ratio. For performance comparison, we have taken Routing overhead, Packet Delivery Ratio, Number of dropped packets and Energy consumption with the increasing number of forwarding nodes. We used UDP based traffic models to analyze the performance of this protocol. We analyzed TCP based traffic models for average end to end delay. We have used the NS-2 simulator.

  20. Performance analysis of switch-based multiuser scheduling schemes with adaptive modulation in spectrum sharing systems

    KAUST Repository

    Qaraqe, Marwa; Abdallah, Mohamed M.; Serpedin, Erchin; Alouini, Mohamed-Slim

    2014-01-01

    the average spectral efficiency by selecting the user that reports the best channel quality. In order to alleviate the relatively high feedback required by the first scheme, a second scheme based on the concept of switched diversity is proposed, where the base

  1. Analisys of Current-Bidirectional Buck-Boost Based Automotive Switch-Mode Audio Amplifier

    DEFF Research Database (Denmark)

    Bolten Maizonave, Gert; Andersen, Michael A. E.; Kjærgaard, Claus

    2011-01-01

    The following study was carried out in order to assess quantitatively the performance of the buck-boost converter when used as switch-mode audio amplifier. It comprises of, to begin with, the delimitation of design criteria based on the state-ofthe- art solution, which is based in a differential ...

  2. Switching-based Mapping and Control for Haptic Teleoperation of Aerial Robots

    NARCIS (Netherlands)

    Mersha, A.Y.; Stramigioli, Stefano; Carloni, Raffaella

    2012-01-01

    This paper deals with the bilateral teleoperation of underactuated aerial robots by means of a haptic interface. In particular, we propose a switching-based state mapping and control algorithm between a rate-based passive controller, which addresses the workspace incompatibility between the master

  3. Lasing cavities and ultra-fast switch based on self-collimation of photonic crystal

    International Nuclear Information System (INIS)

    Zhao Deyin; Zhou Chuanhong; Gong Qian; Jiang Xunya

    2008-01-01

    The lasing cavities and ultra-fast switch based on the self-collimation (SC) of photonic crystal have been studied in this work. Some special properties of these devices are demonstrated, such as the higher quality factors and concise integration of the lasing cavities, the tolerance of the non-parallel reflectors in Fabry-Perot cavities. With nonlinearity, the ultra-fast switch can also be realized around the SC frequency. All these functional devices are designed based on the strong beam confinement of SC

  4. Lasing cavities and ultra-fast switch based on self-collimation of photonic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Deyin; Zhou Chuanhong; Gong Qian; Jiang Xunya [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)], E-mail: xyjiang@mit.edu

    2008-06-07

    The lasing cavities and ultra-fast switch based on the self-collimation (SC) of photonic crystal have been studied in this work. Some special properties of these devices are demonstrated, such as the higher quality factors and concise integration of the lasing cavities, the tolerance of the non-parallel reflectors in Fabry-Perot cavities. With nonlinearity, the ultra-fast switch can also be realized around the SC frequency. All these functional devices are designed based on the strong beam confinement of SC.

  5. Switching Magnetism and Superconductivity with Spin-Polarized Current in Iron-Based Superconductor.

    Science.gov (United States)

    Choi, Seokhwan; Choi, Hyoung Joon; Ok, Jong Mok; Lee, Yeonghoon; Jang, Won-Jun; Lee, Alex Taekyung; Kuk, Young; Lee, SungBin; Heinrich, Andreas J; Cheong, Sang-Wook; Bang, Yunkyu; Johnston, Steven; Kim, Jun Sung; Lee, Jhinhwan

    2017-12-01

    We explore a new mechanism for switching magnetism and superconductivity in a magnetically frustrated iron-based superconductor using spin-polarized scanning tunneling microscopy (SPSTM). Our SPSTM study on single-crystal Sr_{2}VO_{3}FeAs shows that a spin-polarized tunneling current can switch the Fe-layer magnetism into a nontrivial C_{4} (2×2) order, which cannot be achieved by thermal excitation with an unpolarized current. Our tunneling spectroscopy study shows that the induced C_{4} (2×2) order has characteristics of plaquette antiferromagnetic order in the Fe layer and strongly suppresses superconductivity. Also, thermal agitation beyond the bulk Fe spin ordering temperature erases the C_{4} state. These results suggest a new possibility of switching local superconductivity by changing the symmetry of magnetic order with spin-polarized and unpolarized tunneling currents in iron-based superconductors.

  6. Self-Oscillating Soft Switching Envelope Tracking Power Supply for Tetra2 Base Station

    DEFF Research Database (Denmark)

    Høyerby, Mikkel Christian Wendelboe; Andersen, Michael Andreas E.

    2007-01-01

    This paper presents a high-efficiency, high-bandwidth solution to implementing an envelope tracking power supply for the RF power amplifier (RFPA) in a Tetra2 base station. The solution is based on synchronous rectified buck topology, augmented with high-side switch zero-current switching (ZCS......) implemented with a series inductor and an external clamping power supply. Combined with advanced power stage components (die-size MOSFETs), a high-performance fixed-frequency self-oscillating (sliding mode) control strategy and a 4th-order output filter, this leads to a compact, effective and efficient...... overall solution switching at 1MHz with 88-95% efficiency. In a class-AB RFPA amplifying a 50kHz bandwidth QAM Tetra2 signal at 4.6W average output power, the use of tracking supply voltage reduced power dissipation by 25W....

  7. The importance of the rotor in hydrazone-based molecular switches

    Directory of Open Access Journals (Sweden)

    Xin Su

    2012-06-01

    Full Text Available The pH-activated E/Z isomerization of a series of hydrazone-based systems having different functional groups as part of the rotor (R = COMe, CN, Me, H, was studied. The switching efficiency of these systems was compared to that of a hydrazone-based molecular switch (R = COOEt whose E/Z isomerization is fully reversible. It was found that the nature of the R group is critical for efficient switching to occur; the R group should be a moderate H-bond acceptor in order to (i provide enough driving force for the rotor to move upon protonation, and (ii stabilize the obtained Z configuration, to achieve full conversion.

  8. Method and system for a gas tube switch-based voltage source high voltage direct current transmission system

    Science.gov (United States)

    She, Xu; Chokhawala, Rahul Shantilal; Zhou, Rui; Zhang, Di; Sommerer, Timothy John; Bray, James William

    2016-12-13

    A voltage source converter based high-voltage direct-current (HVDC) transmission system includes a voltage source converter (VSC)-based power converter channel. The VSC-based power converter channel includes an AC-DC converter and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and a DC-AC inverter include at least one gas tube switching device coupled in electrical anti-parallel with a respective gas tube diode. The VSC-based power converter channel includes a commutating circuit communicatively coupled to one or more of the at least one gas tube switching devices. The commutating circuit is configured to "switch on" a respective one of the one or more gas tube switching devices during a first portion of an operational cycle and "switch off" the respective one of the one or more gas tube switching devices during a second portion of the operational cycle.

  9. On Tree-Based Phylogenetic Networks.

    Science.gov (United States)

    Zhang, Louxin

    2016-07-01

    A large class of phylogenetic networks can be obtained from trees by the addition of horizontal edges between the tree edges. These networks are called tree-based networks. We present a simple necessary and sufficient condition for tree-based networks and prove that a universal tree-based network exists for any number of taxa that contains as its base every phylogenetic tree on the same set of taxa. This answers two problems posted by Francis and Steel recently. A byproduct is a computer program for generating random binary phylogenetic networks under the uniform distribution model.

  10. Nonbinary Tree-Based Phylogenetic Networks.

    Science.gov (United States)

    Jetten, Laura; van Iersel, Leo

    2018-01-01

    Rooted phylogenetic networks are used to describe evolutionary histories that contain non-treelike evolutionary events such as hybridization and horizontal gene transfer. In some cases, such histories can be described by a phylogenetic base-tree with additional linking arcs, which can, for example, represent gene transfer events. Such phylogenetic networks are called tree-based. Here, we consider two possible generalizations of this concept to nonbinary networks, which we call tree-based and strictly-tree-based nonbinary phylogenetic networks. We give simple graph-theoretic characterizations of tree-based and strictly-tree-based nonbinary phylogenetic networks. Moreover, we show for each of these two classes that it can be decided in polynomial time whether a given network is contained in the class. Our approach also provides a new view on tree-based binary phylogenetic networks. Finally, we discuss two examples of nonbinary phylogenetic networks in biology and show how our results can be applied to them.

  11. Gallium nitride based transistors for high-efficiency microwave switch-mode amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Maroldt, Stephan

    2012-07-01

    Highly-efficient switch-mode power amplifiers form key elements in future fully-digital base stations for mobile communication. This novel digital base station concept reduces system energy consumption, complexity, size and costs, while the flexibility in terms of multi-band operation and signal modulation improves. In this work, innovative core circuits for digital high-efficiency class-D and class-S power amplifiers based on gallium nitride (GaN) technology were developed for the application in digital base stations. A combination of optimized GaN devices and improvements in circuit design allow a highly-efficient switch-mode operation at mobile communication frequencies between 0.45 GHz and 2 GHz. Transistor device modeling for switch-mode operation, the simulation environment, and a broadband measurement system were established for the design and evaluation of digital switchmode power amplifiers. The design of broadband core circuits for switch-mode amplifier concepts was analyzed for dual-stage amplifier circuits, using an initial GaN technology with a gate length of 0.25 {mu}m. A speed-enhanced driver stage improved the circuit switching speed sufficiently above 1 GHz. Speed and efficiency of the amplifier core circuits were studied related to transistor parameters like cut-off frequency or gate capacitance. A reduced gate length was found to improve the switching speed, while a lower on-resistance allows the reduction of the inherent static losses of the GaN-based switches. Apart from this, the restriction of a 50 Ohm environment was found to be a major output power and switching speed limitation, due to a poor switching drive capability of the input capacitance of the GaN circuit. Finally, the optimized transistor and circuit design with an output gate width of 1.2 mm were effectively implemented in the given environment for an operation up to 2 GHz with a high drain efficiency of >65% and a digital output power of 5 W. A maximum output power of 9.7 W and a

  12. Control strategy based on SPWM switching patterns for grid connected photovoltaic inverter

    Science.gov (United States)

    Hassaine, L.; Mraoui, A.

    2017-02-01

    Generally, for lower installation of photovoltaic systems connected to the grid, pulse width modulation (PWM) is a widely used technique for controlling the voltage source inverters injects currents into the grid. The current injected must be sinusoidal with reduced harmonic distortion. In this paper, a digital implementation of a control strategy based on PWM switching patterns for an inverter for photovoltaic system connected to the grid is presented. This strategy synchronize a sinusoidal inverter output current with a grid voltage The digital implementation of the proposed PWM switching pattern when is compared with the conventional one exhibit the advantage: Simplicity, reduction of the memory requirements and power calculation for the control

  13. Atmel Microcontroller Based Soft Switched PWM ZVS Full Bridge DC to DC Converter

    Directory of Open Access Journals (Sweden)

    DEEPAK KUMAR NAYAK

    2010-12-01

    Full Text Available This paper deals with the simulation and implementation of soft switched PWM ZVS full bridge DC to DC converter. The 48V DC is efficiently reduced to 12V DC using a DC to DC converter. This converter has advantages like reduced switching losses, stresses and EMI. Input DC is converted into high frequency AC and it is stepped down to 12V level. Later it is rectified using a full wave rectifier. Laboratory model of microcontroller based DC to DC converter is fabricated and tested. The experimental results are compared with the simulation results.

  14. Clock-Frequency Switching Technique for Energy Saving of Microcontroller Unit (MCU-Based Sensor Node

    Directory of Open Access Journals (Sweden)

    Pumin Duangmanee

    2018-05-01

    Full Text Available In this paper; a technique is proposed for reducing the energy consumption of microcontroller-based sensor nodes by switching the operating clock between low and high frequencies. The proposed concept is motivated by the fact that if the application codes of the microcontroller unit (MCU consist of no-wait state instruction sets, it consumes less energy when it operates with a higher frequency. When the application code of the MCU consists of wait instruction sets; e.g., a wait acknowledge signal, it switches to low clock frequency. The experimental results confirm that the proposed technique can reduce the MCU energy consumption up to 66.9%.

  15. Tungsten disulphide based all fiber Q-switching cylindrical-vector beam generation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, J.; Yan, K.; Zhou, Y. [Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026 (China); Xu, L. X., E-mail: xulixin@ustc.edu.cn; Gu, C. [Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026 (China); Haixi Collaborative Innovation Center for New Display Devices and Systems Integration, Fuzhou University, Fuzhou 350002 (China); Zhan, Q. W. [Electro-Optics Program, University of Dayton, Dayton, Ohio 45469 (United States)

    2015-11-09

    We proposed and demonstrated an all fiber passively Q-switching laser to generate cylindrical-vector beam, a two dimensional material, tungsten disulphide (WS{sub 2}), was adopted as a saturable absorber inside the laser cavity, while a few-mode fiber Bragg grating was used as a transverse mode-selective output coupler. The repetition rate of the Q-switching output pulses can be varied from 80 kHz to 120 kHz with a shortest duration of 958 ns. Attributed to the high damage threshold and polarization insensitivity of the WS{sub 2} based saturable absorber, the radially polarized beam and azimuthally polarized beam can be easily generated in the Q-switching fiber laser.

  16. Design of Measurement and Control System of Composite Fast Transfer Switch Based on PLC

    Directory of Open Access Journals (Sweden)

    ZHANG Hong-yi

    2017-06-01

    Full Text Available The fast transfer switch gets more extensive application in the power supply system along with the raising of power supply requirement for continuity and reliability in the sensitivity loads such as in airport,military place,hospital and large scale industrial production line. Therefore it is important that how to make fast transfer switch run safely and reliably. The paper expatiated the structure and principle of a fast transfer switch based on mechanical and electronic compound technology,and,according to the basic requirement and the characteristic of the fast transfer switch,a PLC mastered measuring and controlling system has been designed to raise the operation reliability of the fast transfer switch.

  17. Design of an Ultra-wideband Pseudo Random Coded MIMO Radar Based on Radio Frequency Switches

    Directory of Open Access Journals (Sweden)

    Su Hai

    2017-02-01

    Full Text Available A Multiple-Input Multiple-Output (MIMO ultra-wideband radar can detect the range and azimuth information of targets in real time. It is widely used for geological surveys, life rescue, through-wall tracking, and other military or civil fields. This paper presents the design of an ultra-wideband pseudo random coded MIMO radar that is based on Radio Frequency (RF switches and implements a MIMO radar system. RF switches are employed to reduce cost and complexity of the system. As the switch pressure value is limited, the peak power of the transmitting signal is 18 dBm. The ultra-wideband radar echo is obtained by hybrid sampling, and pulse compression is computed by Digital Signal Processors (DSPs embedded in an Field-Programmable Gate Array (FPGA to simplify the signal process. The experiment illustrates that the radar system can detect the range and azimuth information of targets in real time.

  18. The dynamics of technological discontinuities : a patent citation network analysis of telecommunication switches

    NARCIS (Netherlands)

    Martinelli, A.

    2010-01-01

    This work focuses on the long-term structural evolution of the telecommunication switching industry, analyzing both the technology and the firm level. The first contribution of this work is in the empirical representation of technological change. Following the growing field of research about the use

  19. Scalable optical packet switch architecture for low latency and high load computer communication networks

    NARCIS (Netherlands)

    Calabretta, N.; Di Lucente, S.; Nazarathy, Y.; Raz, O.; Dorren, H.J.S.

    2011-01-01

    High performance computer and data-centers require PetaFlop/s processing speed and Petabyte storage capacity with thousands of low-latency short link interconnections between computers nodes. Switch matrices that operate transparently in the optical domain are a potential way to efficiently

  20. 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.

  1. Switching speed in resistive random access memories (RRAMS) based on plastic semiconductor

    NARCIS (Netherlands)

    Rocha, P.R.F.; Gomes, H.L.; Kiazadeh, A.; Chen, Qian; Leeuw, de D.M.; Meskers, S.C.J.

    2011-01-01

    This work addresses non-volatile memories based on metal-oxide polymer diodes. We make a thorough investigation into the static and dynamic behavior. Current-voltage characteristics with varying voltage ramp speed demonstrate that the internal capacitive double-layer structure inhibits the switching

  2. SDRAM-based packet buffer model for high speed switches

    DEFF Research Database (Denmark)

    Rasmussen, Anders; Ruepp, Sarah Renée; Berger, Michael Stübert

    2011-01-01

    based on the specifications of a real-life DDR3-SDRAM chip. Based on this model the performance of different schemes for optimizing the performance of such a packet buffer can be evaluated. The purpose of this study is to find efficient schemes for memory mapping of the packet queues and I/O traffic...

  3. NM-Net Gigabit-based Implementation on Core Network Facilities and Performance Design Hierarchy

    International Nuclear Information System (INIS)

    Raja Murzaferi Raja Moktar; Mohd Fauzi Haris; Siti Nurbahyah Hamdan

    2013-01-01

    Nuclear Malaysia computing network or NM-net has been gradually developed since 1990s. Since then it has been the main backbone of inter networking on agency's IT infrastructure, serving users ranging from researchers to operational staffs. Main network operating center or NOC is situated in Block 15 and linkup via fiber or UTP cabling to adjacent main network blocks (18, 29, 11 and 44-Dengkil) and later to other blocks enabling network connections. In 2009 the main core network has been built up form several switches up link to form the main networking switch, while on the adjacent main block networks are mainly based on fast Ethernet technology . With current research and operational tasks highly dependent on IT infrastructure that is being enabled through NM-Net, the performance of the infrastructure are most critical. This paper will discuss NM-Net implementing gigabit-based networking system and performance network design hierarchy in order to achieve highest availability of inter networking services in the agency thus catalyzing Nuclear Malaysia future research initiative. (author)

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

    DEFF Research Database (Denmark)

    Feliu, Elisenda; Wiuf, C.

    2012-01-01

    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...... precludes the existence of degenerate steady states. Further, we relate injectivity of a network to that of the network obtained by adding outflow, or degradation, reactions for all species....

  5. An acoustical model based monitoring network

    NARCIS (Netherlands)

    Wessels, P.W.; Basten, T.G.H.; Eerden, F.J.M. van der

    2010-01-01

    In this paper the approach for an acoustical model based monitoring network is demonstrated. This network is capable of reconstructing a noise map, based on the combination of measured sound levels and an acoustic model of the area. By pre-calculating the sound attenuation within the network the

  6. Call for Papers: Photonics in Switching

    Science.gov (United States)

    Wosinska, Lena; Glick, Madeleine

    2006-04-01

    Call for Papers: Photonics in Switching Guest Editors: Lena Wosinska, Royal Institute of Technology (KTH) / ICT Sweden Madeleine Glick, Intel Research, Cambridge, UK Technologies based on DWDM systems allow data transmission with bit rates of Tbit/s on a single fiber. To facilitate this enormous transmission volume, high-capacity and high-speed network nodes become inevitable in the optical network. Wideband switching, WDM switching, optical burst switching (OBS), and optical packet switching (OPS) are promising technologies for harnessing the bandwidth of WDM optical fiber networks in a highly flexible and efficient manner. As a number of key optical component technologies approach maturity, photonics in switching is becoming an increasingly attractive and practical solution for the next-generation of optical networks. The scope of this special issue is focused on the technology and architecture of optical switching nodes, including the architectural and algorithmic aspects of high-speed optical networks. Scope of Submission The scope of the papers includes, but is not limited to, the following topics: WDM node architectures Novel device technologies enabling photonics in switching, such as optical switch fabrics, optical memory, and wavelength conversion Routing protocols WDM switching and routing Quality of service Performance measurement and evaluation Next-generation optical networks: architecture, signaling, and control Traffic measurement and field trials Optical burst and packet switching OBS/OPS node architectures Burst/Packet scheduling and routing algorithms Contention resolution/avoidance strategies Services and applications for OBS/OPS (e.g., grid networks, storage-area networks, etc.) Burst assembly and ingress traffic shaping Hybrid OBS/TDM or OBS/wavelength routing Manuscript Submission To submit to this special issue, follow the normal procedure for submission to JON and select ``Photonics in Switching' in the features indicator of the online

  7. Study on multiple-hops performance of MOOC sequences-based optical labels for OPS networks

    Science.gov (United States)

    Zhang, Chongfu; Qiu, Kun; Ma, Chunli

    2009-11-01

    In this paper, we utilize a new study method that is under independent case of multiple optical orthogonal codes to derive the probability function of MOOCS-OPS networks, discuss the performance characteristics for a variety of parameters, and compare some characteristics of the system employed by single optical orthogonal code or multiple optical orthogonal codes sequences-based optical labels. The performance of the system is also calculated, and our results verify that the method is effective. Additionally it is found that performance of MOOCS-OPS networks would, negatively, be worsened, compared with single optical orthogonal code-based optical label for optical packet switching (SOOC-OPS); however, MOOCS-OPS networks can greatly enlarge the scalability of optical packet switching networks.

  8. Digital switched hydraulics

    Science.gov (United States)

    Pan, Min; Plummer, Andrew

    2018-06-01

    This paper reviews recent developments in digital switched hydraulics particularly the switched inertance hydraulic systems (SIHSs). The performance of SIHSs is presented in brief with a discussion of several possible configurations and control strategies. The soft switching technology and high-speed switching valve design techniques are discussed. Challenges and recommendations are given based on the current research achievements.

  9. A Quantum Cryptography Communication Network Based on Software Defined Network

    Directory of Open Access Journals (Sweden)

    Zhang Hongliang

    2018-01-01

    Full Text Available With the development of the Internet, information security has attracted great attention in today’s society, and quantum cryptography communication network based on quantum key distribution (QKD is a very important part of this field, since the quantum key distribution combined with one-time-pad encryption scheme can guarantee the unconditional security of the information. The secret key generated by quantum key distribution protocols is a very valuable resource, so making full use of key resources is particularly important. Software definition network (SDN is a new type of network architecture, and it separates the control plane and the data plane of network devices through OpenFlow technology, thus it realizes the flexible control of the network resources. In this paper, a quantum cryptography communication network model based on SDN is proposed to realize the flexible control of quantum key resources in the whole cryptography communication network. Moreover, we propose a routing algorithm which takes into account both the hops and the end-to-end availible keys, so that the secret key generated by QKD can be used effectively. We also simulate this quantum cryptography communication network, and the result shows that based on SDN and the proposed routing algorithm the performance of this network is improved since the effective use of the quantum key resources.

  10. Experimental determination of harmonic conditions amplification in a distribution network by capacitor bank switching

    DEFF Research Database (Denmark)

    Baloi, Alexandru; Kocewiak, Lukasz Hubert; Bak, Claus Leth

    2012-01-01

    The paper presents a study comprising laboratory measurements for the evaluation of the harmonic amplification due to capacitor bank switching. The mathematical model of the amplification factors of the current flowing on the circuit elements is presented. Theoretical aspects, regarding the total...... harmonic distortion (THD) of the capacitor current computed using the amplification factor, are originally presented. Nonlinear loads as six pulse rectifier and National Instruments measurement sensors together with LabView software were used on the laboratory set-up. The main instrument of the method...... is the harmonic impedance, “seen” in the bus of the capacitor bank switching. MatLab Simulink is used for the determination of the harmonic impedance....

  11. Modeling of driver's collision avoidance maneuver based on controller switching model.

    Science.gov (United States)

    Kim, Jong-Hae; Hayakawa, Soichiro; Suzuki, Tatsuya; Hayashi, Koji; Okuma, Shigeru; Tsuchida, Nuio; Shimizu, Masayuki; Kido, Shigeyuki

    2005-12-01

    This paper presents a modeling strategy of human driving behavior based on the controller switching model focusing on the driver's collision avoidance maneuver. The driving data are collected by using the three-dimensional (3-D) driving simulator based on the CAVE Automatic Virtual Environment (CAVE), which provides stereoscopic immersive virtual environment. In our modeling, the control scenario of the human driver, that is, the mapping from the driver's sensory information to the operation of the driver such as acceleration, braking, and steering, is expressed by Piecewise Polynomial (PWP) model. Since the PWP model includes both continuous behaviors given by polynomials and discrete logical conditions, it can be regarded as a class of Hybrid Dynamical System (HDS). The identification problem for the PWP model is formulated as the Mixed Integer Linear Programming (MILP) by transforming the switching conditions into binary variables. From the obtained results, it is found that the driver appropriately switches the "control law" according to the sensory information. In addition, the driving characteristics of the beginner driver and the expert driver are compared and discussed. These results enable us to capture not only the physical meaning of the driving skill but the decision-making aspect (switching conditions) in the driver's collision avoidance maneuver as well.

  12. Data Transparent and Polarization Insensitive All-Optical Switch based on Fibers with Enhanced Nonlinearity

    Directory of Open Access Journals (Sweden)

    M. Komanec

    2014-09-01

    Full Text Available We have developed a data transparent optical packet switch prototype employing wavelength conversion based on four-wave mixing. The switch is composed of an electro-optical control unit and an all-optical switching segment. To achieve higher switching efficiencies, Ge-doped silica suspended-core and chalcogenide arsenicselenide single-mode fibers were experimentally evaluated and compared to conventional highly-nonlinear fiber. Improved connectorization technology has been developed for Ge-doped suspended-core fiber, where we achieved connection losses of 0.9 dB. For the arsenic-selenide fiber we present a novel solid joint technology, with connection losses of only 0.25 dB, which is the lowest value presented up-to-date. Conversion efficiency of -13.7 dB was obtained for the highly-nonlinear fiber, which is in perfect correlation with previously published results and thus verifies the functionality of the prototype. Conversion efficiency of -16.1 dB was obtained with arsenic-selenide fiber length reduced to five meters within simulations, based on measurement results with a 26 m long component. Employment of such a short arsenic-selenide fiber segment allows significant broadening of the wavelength conversion spectral range due to possible neglection of dispersion.

  13. Geographical constraints to range-based attacks on links in complex networks

    International Nuclear Information System (INIS)

    Gong Baihua; Liu Jun; Huang Liang; Yang Kongqing; Yang Lei

    2008-01-01

    In this paper, we studied range-based attacks on links in geographically constrained scale-free networks and found that there is a continuous switching of roles of short- and long-range attacks on links when tuning the geographical constraint strength. Our results demonstrate that the geography has a significant impact on the network efficiency and security; thus one can adjust the geographical structure to optimize the robustness and the efficiency of the networks. We introduce a measurement of the impact of links on the efficiency of the network, and an effective attacking strategy is suggested

  14. Cut set-based risk and reliability analysis for arbitrarily interconnected networks

    Science.gov (United States)

    Wyss, Gregory D.

    2000-01-01

    Method for computing all-terminal reliability for arbitrarily interconnected networks such as the United States public switched telephone network. The method includes an efficient search algorithm to generate minimal cut sets for nonhierarchical networks directly from the network connectivity diagram. Efficiency of the search algorithm stems in part from its basis on only link failures. The method also includes a novel quantification scheme that likewise reduces computational effort associated with assessing network reliability based on traditional risk importance measures. Vast reductions in computational effort are realized since combinatorial expansion and subsequent Boolean reduction steps are eliminated through analysis of network segmentations using a technique of assuming node failures to occur on only one side of a break in the network, and repeating the technique for all minimal cut sets generated with the search algorithm. The method functions equally well for planar and non-planar networks.

  15. Defect engineering: reduction effect of hydrogen atom impurities in HfO2-based resistive-switching memory devices

    International Nuclear Information System (INIS)

    Kim, Seonghyun; Park, Jubong; Jung, Seungjae; Lee, Wootae; Shin, Jungho; Hwang, Hyunsang; Lee, Daeseok; Woo, Jiyong; Choi, Godeuni

    2012-01-01

    In this study, we propose a new and effective methodology for improving the resistive-switching performance of memory devices by high-pressure hydrogen annealing under ambient conditions. The reduction effect results in the uniform creation of oxygen vacancies that in turn enable forming-free operation and afford uniform switching characteristics. In addition, H + and mobile hydroxyl (OH − ) ions are generated, and these induce fast switching operation due to the higher mobility compared to oxygen ions. Defect engineering, specifically, the introduction of hydrogen atom impurities, improves the device performance for metal–oxide-based resistive-switching random access memory devices. (paper)

  16. ENERGY AWARE NETWORK: BAYESIAN BELIEF NETWORKS BASED DECISION MANAGEMENT SYSTEM

    Directory of Open Access Journals (Sweden)

    Santosh Kumar Chaudhari

    2011-06-01

    Full Text Available A Network Management System (NMS plays a very important role in managing an ever-evolving telecommunication network. Generally an NMS monitors & maintains the health of network elements. The growing size of the network warrants extra functionalities from the NMS. An NMS provides all kinds of information about networks which can be used for other purposes apart from monitoring & maintaining networks like improving QoS & saving energy in the network. In this paper, we add another dimension to NMS services, namely, making an NMS energy aware. We propose a Decision Management System (DMS framework which uses a machine learning technique called Bayesian Belief Networks (BBN, to make the NMS energy aware. The DMS is capable of analysing and making control decisions based on network traffic. We factor in the cost of rerouting and power saving per port. Simulations are performed on standard network topologies, namely, ARPANet and IndiaNet. It is found that ~2.5-6.5% power can be saved.

  17. Machine learning based switching model for electricity load forecasting

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Shu; Lee, Wei-Jen [Energy Systems Research Center, The University of Texas at Arlington, 416 S. College Street, Arlington, TX 76019 (United States); Chen, Luonan [Department of Electronics, Information and Communication Engineering, Osaka Sangyo University, 3-1-1 Nakagaito, Daito, Osaka 574-0013 (Japan)

    2008-06-15

    In deregulated power markets, forecasting electricity loads is one of the most essential tasks for system planning, operation and decision making. Based on an integration of two machine learning techniques: Bayesian clustering by dynamics (BCD) and support vector regression (SVR), this paper proposes a novel forecasting model for day ahead electricity load forecasting. The proposed model adopts an integrated architecture to handle the non-stationarity of time series. Firstly, a BCD classifier is applied to cluster the input data set into several subsets by the dynamics of the time series in an unsupervised manner. Then, groups of SVRs are used to fit the training data of each subset in a supervised way. The effectiveness of the proposed model is demonstrated with actual data taken from the New York ISO and the Western Farmers Electric Cooperative in Oklahoma. (author)

  18. Machine learning based switching model for electricity load forecasting

    Energy Technology Data Exchange (ETDEWEB)

    Fan Shu [Energy Systems Research Center, University of Texas at Arlington, 416 S. College Street, Arlington, TX 76019 (United States); Chen Luonan [Department of Electronics, Information and Communication Engineering, Osaka Sangyo University, 3-1-1 Nakagaito, Daito, Osaka 574-0013 (Japan); Lee, Weijen [Energy Systems Research Center, University of Texas at Arlington, 416 S. College Street, Arlington, TX 76019 (United States)], E-mail: wlee@uta.edu

    2008-06-15

    In deregulated power markets, forecasting electricity loads is one of the most essential tasks for system planning, operation and decision making. Based on an integration of two machine learning techniques: Bayesian clustering by dynamics (BCD) and support vector regression (SVR), this paper proposes a novel forecasting model for day ahead electricity load forecasting. The proposed model adopts an integrated architecture to handle the non-stationarity of time series. Firstly, a BCD classifier is applied to cluster the input data set into several subsets by the dynamics of the time series in an unsupervised manner. Then, groups of SVRs are used to fit the training data of each subset in a supervised way. The effectiveness of the proposed model is demonstrated with actual data taken from the New York ISO and the Western Farmers Electric Cooperative in Oklahoma.

  19. Machine learning based switching model for electricity load forecasting

    International Nuclear Information System (INIS)

    Fan Shu; Chen Luonan; Lee, Weijen

    2008-01-01

    In deregulated power markets, forecasting electricity loads is one of the most essential tasks for system planning, operation and decision making. Based on an integration of two machine learning techniques: Bayesian clustering by dynamics (BCD) and support vector regression (SVR), this paper proposes a novel forecasting model for day ahead electricity load forecasting. The proposed model adopts an integrated architecture to handle the non-stationarity of time series. Firstly, a BCD classifier is applied to cluster the input data set into several subsets by the dynamics of the time series in an unsupervised manner. Then, groups of SVRs are used to fit the training data of each subset in a supervised way. The effectiveness of the proposed model is demonstrated with actual data taken from the New York ISO and the Western Farmers Electric Cooperative in Oklahoma

  20. High-power electro-optic switch technology based on novel transparent ceramic

    Science.gov (United States)

    Xue-Jiao, Zhang; Qing, Ye; Rong-Hui, Qu; Hai-wen, Cai

    2016-03-01

    A novel high-power polarization-independent electro-optic switch technology based on a reciprocal structure Sagnac interferometer and a transparent quadratic electro-optic ceramic is proposed and analyzed theoretically and experimentally. The electro-optic ceramic is used as a phase retarder for the clockwise and counter-clockwise polarized light, and their polarization directions are adjusted to their orthogonal positions by using two half-wave plates. The output light then becomes polarization-independent with respect to the polarization direction of the input light. The switch characteristics, including splitter ratios and polarization states, are theoretically analyzed and simulated in detail by the matrix multiplication method. An experimental setup is built to verify the analysis and experimental results. A new component ceramic is used and a non-polarizing cube beam splitter (NPBS) replaces the beam splitter (BS) to lower the ON/OFF voltage to 305 V and improve the extinction ratio by 2 dB. Finally, the laser-induced damage threshold for the proposed switch is measured and discussed. It is believed that potential applications of this novel polarization-independent electro-optic switch technology will be wide, especially for ultrafast high-power laser systems. Project supported by the National Natural Science Foundation of China (Grant Nos. 61137004, 61405218, and 61535014).

  1. High-power electro-optic switch technology based on novel transparent ceramic

    International Nuclear Information System (INIS)

    Zhang Xue-Jiao; Ye Qing; Qu Rong-Hui; Cai Hai-wen

    2016-01-01

    A novel high-power polarization-independent electro-optic switch technology based on a reciprocal structure Sagnac interferometer and a transparent quadratic electro-optic ceramic is proposed and analyzed theoretically and experimentally. The electro-optic ceramic is used as a phase retarder for the clockwise and counter-clockwise polarized light, and their polarization directions are adjusted to their orthogonal positions by using two half-wave plates. The output light then becomes polarization-independent with respect to the polarization direction of the input light. The switch characteristics, including splitter ratios and polarization states, are theoretically analyzed and simulated in detail by the matrix multiplication method. An experimental setup is built to verify the analysis and experimental results. A new component ceramic is used and a non-polarizing cube beam splitter (NPBS) replaces the beam splitter (BS) to lower the ON/OFF voltage to 305 V and improve the extinction ratio by 2 dB. Finally, the laser-induced damage threshold for the proposed switch is measured and discussed. It is believed that potential applications of this novel polarization-independent electro-optic switch technology will be wide, especially for ultrafast high-power laser systems. (paper)

  2. Resistive switching characteristics of HfO2-based memory devices on flexible plastics.

    Science.gov (United States)

    Han, Yong; Cho, Kyoungah; Park, Sukhyung; Kim, Sangsig

    2014-11-01

    In this study, we examine the characteristics of HfO2-based resistive switching random access memory (ReRAM) devices on flexible plastics. The Pt/HfO2/Au ReRAM devices exhibit the unipolar resistive switching behaviors caused by the conducting filaments. From the Auger depth profiles of the HfO2 thin film, it is confirmed that the relatively lower oxygen content in the interface of the bottom electrode is responsible for the resistive switching by oxygen vacancies. And the unipolar resistive switching behaviors are analyzed from the C-V characteristics in which negative and positive capacitances are measured in the low-resistance state and the high-resistance state, respectively. The devices have a high on/off ratio of 10(4) and the excellent retention properties even after a continuous bending test of two thousand cycles. The correlation between the device size and the memory characteristics is investigated as well. A relatively smaller-sized device having a higher on/off ratio operates at a higher voltage than a relatively larger-sized device.

  3. Design of Low Inductance Switching Power Cell for GaN HEMT Based Inverter

    DEFF Research Database (Denmark)

    Gurpinar, Emre; Iannuzzo, Francesco; Yang, Yongheng

    2018-01-01

    . The design of gate drivers for the GaN HEMT devices is presented. Parasitic inductance and resistance of the proposed design are extracted with finite element analysis and discussed. Common-mode behaviours based on the SPICE model of the converter are analyzed. Experimental results on the designed 3L......In this paper, an ultra-low inductance power cell is designed for a three-Level Active Neutral Point Clamped (3LANPC) based on 650 V gallium nitride (GaN) HEMT devices. The 3L-ANPC topology with GaN HEMT devices and the selected modulation scheme suitable for wide-bandgap (WBG) devices...... are presented. The commutation loops, which mainly contribute to voltage overshoots and increase of switching losses, are discussed. The ultra-low inductance power cell design based on a four-layer Printed Circuit Board (PCB) with the aim to maximize the switching performance of GaN HEMTs is explained...

  4. Distributed SCI-based data acquisition systems constructed from SCI bridges and SCI switches

    International Nuclear Information System (INIS)

    Wu Bin; Kristiansen, E.; Skaali, B.; Bogaerts, A.; Divia, R.; ); Perea, E.

    1994-01-01

    The IEEE standard 1596-1992, Scalable Coherent Interface (SCI) provides novel possibilities to build data acquisition systems for large and very high rate experiments in high energy physics. The RD24 project at CERN started two years ago to investigate applications of SCI to data acquisition at the Large Hadron Collider (LHC). As part of the RD24 project, simulation of large SCI-based data acquisition systems is performed by a simulator written in the object-oriented language MODSIM II. The goal of this paper is to investigate the difference between SCI switch- and SCI-based systems, and to study some of the design criteria for the SCI switch element to form the interconnection of large scale SCI-based data acquisition systems. 15 refs., 14 figs., 2 tabs

  5. Study of magnetization switching for MRAM based memory technologies

    Science.gov (United States)

    Pham, Huy

    Amphibian alkaloids are attractive targets for synthesis due to their biological activity. An important class of amphibian alkaloids is the 2,5-disubstituted pyrrolidine-based family of compounds. There are many synthetic approaches for the preparation of the trans-2,5-disubstituted pyrrolidines, but methods for the construction of the cis-2,5-pyrrolidines are limited. Therefore, it was desired to develop an enantioselective approach for the preparation of cis-2,5-disubsituted pyrrolidines. (+)-Tropin-2-one derived from cocaine was used as starting material to exploit the inherent stereochemistry for construction of the cis-pyrrolidine ring. This permitted the unequivocal assignment of the absolute configuration of the target pyrrolidine. The structurally simple pyrrolidine alkaloid, 225H, was selected as a target to develop a general synthetic approach. The enantioselective synthesis of 225H was achieved in nine steps and good overall yield. The search for potent cannabinoid receptor partial agonist ligands as potential marijuana addiction therapeutic agents has led to an investigation of the synthesis of diaryl ether hybrid analogues of BAY 59-3074. A series of 2-(3-alkyl-5-hydroxyphenoxy)-6-(trifluoromethyl)benzonitriles, 3-(2-cyano-3-(trifluoromethyl)phenoxy)phenylalkanoates, and (3-(benzyloxy)phenoxy)-6-(trifluoromethyl)benzonitriles were synthesized and evaluated in vitro for CB1 affinity. The olivetol diaryl ether analogue was the most potent ligand of the alkyl series, but the diaryl ester analogues exhibited modest affinity for CB1 receptors. The most potent compound of the series was the 2-(3-(benzyloxy)phenoxy)-6-(trifluoromethyl)benzonitrile. Keywords. amphibian alkaloids, enantioselective synthesis, pyrrolidine, cannabinoid receptor, marijuana.

  6. Motor models and transient analysis for high-temperature, superconductor switch-based adjustable speed drive applications. Final report

    International Nuclear Information System (INIS)

    Bailey, J.M.

    1996-06-01

    New high-temperature superconductor (HTSC) technology may allow development of an energy-efficient power electronics switch for adjustable speed drive (ASD) applications involving variable-speed motors, superconducting magnetic energy storage systems, and other power conversion equipment. This project developed a motor simulation module for determining optimal applications of HTSC-based power switches in ASD systems

  7. Assembly and offset assignment scheme for self-similar traffic in optical burst switched networks

    CSIR Research Space (South Africa)

    Muwonge, KB

    2007-10-01

    Full Text Available at the Label Edge Router (LER) to buffer traffic in the electronic domain. Burst assembly and offset assignment schemes are implemented in a complementary manner to improve QoS of an OBS network. The authors show that OBS network performance is directly related...

  8. IPTV based on IP network and streaming media service station

    Science.gov (United States)

    Sun, Jifeng; Gao, Songbo

    2007-11-01

    IPTV can be a new service performed on the Internet in that network transmission and streaming media technologies are getting mature. In this paper, IPTV system infrastructure of UTStarcom, key technologies deployed, and applications will be discussed and evaluated. The key technologies to achieve IPTV services include 1) codec and compression; 2) streaming media; and 3) broadband networks and access to such networks. The implementation of Media Switch IPTV system in Harbin CNC city network is also discussed.

  9. Nonbinary tree-based phylogenetic networks

    OpenAIRE

    Jetten, Laura; van Iersel, Leo

    2016-01-01

    Rooted phylogenetic networks are used to describe evolutionary histories that contain non-treelike evolutionary events such as hybridization and horizontal gene transfer. In some cases, such histories can be described by a phylogenetic base-tree with additional linking arcs, which can for example represent gene transfer events. Such phylogenetic networks are called tree-based. Here, we consider two possible generalizations of this concept to nonbinary networks, which we call tree-based and st...

  10. Directory Enabled Policy Based Networking; TOPICAL

    International Nuclear Information System (INIS)

    KELIIAA, CURTIS M.

    2001-01-01

    This report presents a discussion of directory-enabled policy-based networking with an emphasis on its role as the foundation for securely scalable enterprise networks. A directory service provides the object-oriented logical environment for interactive cyber-policy implementation. Cyber-policy implementation includes security, network management, operational process and quality of service policies. The leading network-technology vendors have invested in these technologies for secure universal connectivity that transverses Internet, extranet and intranet boundaries. Industry standards are established that provide the fundamental guidelines for directory deployment scalable to global networks. The integration of policy-based networking with directory-service technologies provides for intelligent management of the enterprise network environment as an end-to-end system of related clients, services and resources. This architecture allows logical policies to protect data, manage security and provision critical network services permitting a proactive defense-in-depth cyber-security posture. Enterprise networking imposes the consideration of supporting multiple computing platforms, sites and business-operation models. An industry-standards based approach combined with principled systems engineering in the deployment of these technologies allows these issues to be successfully addressed. This discussion is focused on a directory-based policy architecture for the heterogeneous enterprise network-computing environment and does not propose specific vendor solutions. This document is written to present practical design methodology and provide an understanding of the risks, complexities and most important, the benefits of directory-enabled policy-based networking

  11. Agent-based modeling and network dynamics

    CERN Document Server

    Namatame, Akira

    2016-01-01

    The book integrates agent-based modeling and network science. It is divided into three parts, namely, foundations, primary dynamics on and of social networks, and applications. The book begins with the network origin of agent-based models, known as cellular automata, and introduce a number of classic models, such as Schelling’s segregation model and Axelrod’s spatial game. The essence of the foundation part is the network-based agent-based models in which agents follow network-based decision rules. Under the influence of the substantial progress in network science in late 1990s, these models have been extended from using lattices into using small-world networks, scale-free networks, etc. The book also shows that the modern network science mainly driven by game-theorists and sociophysicists has inspired agent-based social scientists to develop alternative formation algorithms, known as agent-based social networks. The book reviews a number of pioneering and representative models in this family. Upon the gi...

  12. Dual-functional Memory and Threshold Resistive Switching Based on the Push-Pull Mechanism of Oxygen Ions

    KAUST Repository

    Huang, Yi-Jen

    2016-04-07

    The combination of nonvolatile memory switching and volatile threshold switching functions of transition metal oxides in crossbar memory arrays is of great potential for replacing charge-based flash memory in very-large-scale integration. Here, we show that the resistive switching material structure, (amorphous TiOx)/(Ag nanoparticles)/(polycrystalline TiOx), fabricated on the textured-FTO substrate with ITO as the top electrode exhibits both the memory switching and threshold switching functions. When the device is used for resistive switching, it is forming-free for resistive memory applications with low operation voltage (<±1 V) and self-compliance to current up to 50 μA. When it is used for threshold switching, the low threshold current is beneficial for improving the device selectivity. The variation of oxygen distribution measured by energy dispersive X-ray spectroscopy and scanning transmission electron microscopy indicates the formation or rupture of conducting filaments in the device at different resistance states. It is therefore suggested that the push and pull actions of oxygen ions in the amorphous TiOx and polycrystalline TiOx films during the voltage sweep account for the memory switching and threshold switching properties in the device.

  13. Optimize the Power Consumption and SNR of the 3D Photonic High-Radix Switch Architecture Based on Extra Channels and Redundant Rings

    Directory of Open Access Journals (Sweden)

    Jie Jian

    2018-01-01

    Full Text Available The demand from exascale computing has made the design of high-radix switch chips an attractive and challenging research field in EHPC (exascale high-performance computing. The static power, due to the thermal sensitivity and process variation of the microresonator rings, and the cross talk noise of the optical network become the main bottlenecks of the network’s scalability. This paper proposes the analyze model of the trimming power, process variation power, and signal-to-noise ratio (SNR for the Graphein-based high-radix optical switch networks and uses the extra channels and the redundant rings to decrease the trimming power and the process variation power. The paper also explores the SNR under different configurations. The simulation result shows that when using 8 extra channels in the 64×64 crossbar optical network, the trimming power reduces almost 80% and the process variation power decreases 65% by adding 16 redundant rings in the 64×64 crossbar optical network. All of these schemes have little influence on the SNR. Meanwhile, the greater channel spacing has great advantages to decrease the static power and increase the SNR of the optical network.

  14. Reconfigurable high-speed optical fibre networks: Optical wavelength conversion and switching using VCSELs to eliminate channel collisions

    Science.gov (United States)

    Boiyo, Duncan Kiboi; Chabata, T. V.; Kipnoo, E. K. Rotich; Gamatham, R. R. G.; Leitch, A. W. R.; Gibbon, T. B.

    2017-01-01

    We experimentally provide an alternative solution to channel collisions through up-wavelength conversion and switching by using vertical cavity surface-emitting lasers (VCSELs). This has been achieved by utilizing purely optical wavelength conversion on VCSELs at the low attenuation, 1550 nm transmission window. The corresponding transmission and bit error-rate (BER) performance evaluation is also presented. In this paper, two 1550 nm VCSELs with 50-150 GHz channel spacing are modulated with a 10 Gb/s NRZ PRBS 27-1 data and their interferences investigated. A channel interference penalty range of 0.15-1.63 dB is incurred for 150-50 GHz channel spacing without transmission. To avoid channel collisions and to minimize high interference penalties, the transmitting VCSEL with data is injected into the side-mode of a slave VCSEL to obtain a new up converted wavelength. A 16 dB extinction ratio of the incoming wavelength is achieved when a 15 dBm transmitting beam is injected into the side-mode of a -4.5 dBm slave VCSEL. At 8.5 Gb/s, a 1.1 dB conversion and a 0.5 dB transmission penalties are realized when the converted wavelength is transmitted over a 24.7 km G.655 fibre. This work offers a low-cost, effective wavelength conversion and channel switching to reduce channel collision probability by reconfiguring channels at the node of networks.

  15. Observer-based leader-following tracking control under both fixed and switching topologies

    Institute of Scientific and Technical Information of China (English)

    Jinhuan WANG; Pengxiao ZHANG; Zhixin LIU; Xiaoming HU

    2016-01-01

    This paper studies the tracking problem for a class of leader-follower multi-agent systems moving on the plane using observer-based cooperative control strategies. In our set-up, only a subset of the followers can obtain some relative information on the leader. We assume that the control input of the leader is not known to any of the followers while the system matrix is broadcast to all the followers. To track such a leader, an observer-based decentralized feedback controller is designed for each follower and detailed analysis for the convergence is presented for both fixed and switching interaction topologies between agents with the method of common Lyapunov function. We can also generalize the result to the higher dimension case for fixed topology and some special system matrices of the leader for switching topology.

  16. Resistive Switching of Ta2O5-Based Self-Rectifying Vertical-Type Resistive Switching Memory

    Science.gov (United States)

    Ryu, Sungyeon; Kim, Seong Keun; Choi, Byung Joon

    2018-01-01

    To efficiently increase the capacity of resistive switching random-access memory (RRAM) while maintaining the same area, a vertical structure similar to a vertical NAND flash structure is needed. In addition, the sneak-path current through the half-selected neighboring memory cell should be mitigated by integrating a selector device with each RRAM cell. In this study, an integrated vertical-type RRAM cell and selector device was fabricated and characterized. Ta2O5 as the switching layer and TaOxNy as the selector layer were used to preliminarily study the feasibility of such an integrated device. To make the side contact of the bottom electrode with active layers, a thick Al2O3 insulating layer was placed between the Pt bottom electrode and the Ta2O5/TaOxNy stacks. Resistive switching phenomena were observed under relatively low currents (below 10 μA) in this vertical-type RRAM device. The TaOxNy layer acted as a nonlinear resistor with moderate nonlinearity. Its low-resistance-state and high-resistance-state were well retained up to 1000 s.

  17. Filtering of Discrete-Time Switched Neural Networks Ensuring Exponential Dissipative and $l_{2}$ - $l_{\\infty }$ Performances.

    Science.gov (United States)

    Choi, Hyun Duck; Ahn, Choon Ki; Karimi, Hamid Reza; Lim, Myo Taeg

    2017-10-01

    This paper studies delay-dependent exponential dissipative and l 2 - l ∞ filtering problems for discrete-time switched neural networks (DSNNs) including time-delayed states. By introducing a novel discrete-time inequality, which is a discrete-time version of the continuous-time Wirtinger-type inequality, we establish new sets of linear matrix inequality (LMI) criteria such that discrete-time filtering error systems are exponentially stable with guaranteed performances in the exponential dissipative and l 2 - l ∞ senses. The design of the desired exponential dissipative and l 2 - l ∞ filters for DSNNs can be achieved by solving the proposed sets of LMI conditions. Via numerical simulation results, we show the validity of the desired discrete-time filter design approach.

  18. Temperature Control of Gas Chromatograph Based on Switched Delayed System Techniques

    Directory of Open Access Journals (Sweden)

    Xiao-Liang Wang

    2014-01-01

    Full Text Available We address the temperature control problem of the gas chromatograph. We model the temperature control system of the gas chromatograph into a switched delayed system and analyze the stability by common Lyapunov functional technique. The PI controller parameters can be given based on the proposed linear matrix inequalities (LMIs condition and the designed controller can make the temperature of gas chromatograph track the reference signal asymptotically. An experiment is given to illustrate the effectiveness of the stability criterion.

  19. Electrochemical control of quantum interference in anthraquinone-based molecular switches

    DEFF Research Database (Denmark)

    Markussen, Troels; Schiøtz, Jakob; Thygesen, Kristian Sommer

    2010-01-01

    Using first-principles calculations we analyze the electronic transport properties of a recently proposed anthraquinone-based electrochemical switch. Robust conductance on/off ratios of several orders of magnitude are observed due to destructive quantum interference present in the anthraquinone...... of hopping via the localized orbitals. The topology of the tight-binding model, which is dictated by the symmetries of the molecular orbitals, determines the amount of quantum interference....

  20. Robust passive control for Internet-based switching systems with time-delay

    Energy Technology Data Exchange (ETDEWEB)

    Guan Zhihong [Department of Control Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Zhang Hao [Department of Control Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)], E-mail: ehao79@163.com; Yang Shuanghua [Department of Computer Science, Loughborough University, Loughborough LE11 3TU (United Kingdom)

    2008-04-15

    In this paper, based on remote control and local control strategy, a class of hybrid multi-rate control models with time-delay and switching controllers are formulated and the problem of robust passive control for this discrete system is investigated. By Lyapunov-Krasovskii function and applying it to a descriptor model transformation some new sufficient conditions in form of LMIs are derived. A numerical example is given to illustrate the effectiveness of the theoretical result.

  1. Playable One-Switch Video Games for Children with Severe Motor Disabilities Based on GNomon

    OpenAIRE

    ACED LOPEZ, Sebastian; Corno, Fulvio; DE RUSSIS, Luigi

    2015-01-01

    Being able to play games in early years is very important for the development of children. Even though, children with physical disabilities encounter several obstacles that exclude them from engaging in many popular games. In particular, children with severe motor disabilities that rely on one-switch interfaces for accessing electronic devices find dynamic video games completely unplayable. In this paper we present the development and evaluation of GNomon: a framework, based on the NOMON inte...

  2. Performance comparison of hybrid resistive switching devices based on solution-processable nanocomposites

    Science.gov (United States)

    Rajan, Krishna; Roppolo, Ignazio; Bejtka, Katarzyna; Chiappone, Annalisa; Bocchini, Sergio; Perrone, Denis; Pirri, Candido Fabrizio; Ricciardi, Carlo; Chiolerio, Alessandro

    2018-06-01

    The present work compares the influence of different polymer matrices on the performance of planar asymmetric Resistive Switching Devices (RSDs) based on silver nitrate and Ionic Liquid (IL). PolyVinyliDene Fluoride-HexaFluoroPropylene (PVDF-HFP), PolyEthylene Oxide (PEO), PolyMethyl MethAcrylate (PMMA) and a blend of PVDF-HFP and PEO were used as matrices and compared. RSDs represent perhaps the most promising electron device to back the More than Moore development, and our approach through functional polymers enables low temperature processing and gives compatibility towards flexible/stretchable/wearable equipment. The switching mechanism in all the four sample families is explained by means of a filamentary conduction. A huge difference in the cyclability and the On/Off ratio is experienced when changing the active polymers and explained based on the polymer crystallinity degree and general morphology of the prepared nanocomposite. It is worth noting that all the RSDs discussed here present good switching behaviour with reasonable endurance. The current study displays one of the most cost-effective and effortless ways to produce an RSD based on solution-processable materials.

  3. A random network based, node attraction facilitated network evolution method

    Directory of Open Access Journals (Sweden)

    WenJun Zhang

    2016-03-01

    Full Text Available In present study, I present a method of network evolution that based on random network, and facilitated by node attraction. In this method, I assume that the initial network is a random network, or a given initial network. When a node is ready to connect, it tends to link to the node already owning the most connections, which coincides with the general rule (Barabasi and Albert, 1999 of node connecting. In addition, a node may randomly disconnect a connection i.e., the addition of connections in the network is accompanied by the pruning of some connections. The dynamics of network evolution is determined of the attraction factor Lamda of nodes, the probability of node connection, the probability of node disconnection, and the expected initial connectance. The attraction factor of nodes, the probability of node connection, and the probability of node disconnection are time and node varying. Various dynamics can be achieved by adjusting these parameters. Effects of simplified parameters on network evolution are analyzed. The changes of attraction factor Lamda can reflect various effects of the node degree on connection mechanism. Even the changes of Lamda only will generate various networks from the random to the complex. Therefore, the present algorithm can be treated as a general model for network evolution. Modeling results show that to generate a power-law type of network, the likelihood of a node attracting connections is dependent upon the power function of the node's degree with a higher-order power. Matlab codes for simplified version of the method are provided.

  4. An efficient hexagonal switched beam antenna structure based on Fabry-Perot cavity leaky-wave antenna

    Science.gov (United States)

    Aymen El Cafsi, Mohamed; Nedil, Mourad; Osman, Lotfi; Gharsallah, Ali

    2015-11-01

    A novel design of switched beam antenna (SBA) system based on Fabry-Perot cavity leaky-wave antenna (FPC LWA) is designed and fabricated for base station operating in the unlicensed ISM central frequency band at 5.8 GHz of the wireless local area network (WLAN) standard. The proposed SBA is designed with hexagonal shape of FPC LWA Arrays in order to get 360° of coverage. The single element of FPC LWA array is composed of a patch antenna and covered by a Partially Reflective Surface (PRS), which is composed of a Metal Strip Grating and printed on a high permittivity Superstrate. First, the Transmission Line Model of FPC LWA is introduced to analyse and calculate the far-field components in E- and H planes by using the Transverse Equivalent Network. This approach is then compared with other full wave's commercial software such as Ansoft HFSS and CST Microwave Studio. Second, a parametric study is performed to evaluate the effect of the angle formed by the two successive FPC LWA on the radiation efficiency of the activate sector. To examine the performance of the proposed SBA, experimental prototype was fabricated and measured. As a result, multiple orthogonal beams (six beams) of 10 dBi of gain with low Side Lobes Level and 360° of coverage are produced. This SBA structure is suitable for WLAN communication systems.

  5. Single molecular switch based on thiol tethered iron(II)clathrochelate on gold

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, Subramanian [Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, Tuwima 10, 10-747 Olsztyn (Poland); Voloshin, Yan Z. [Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences, 119991 Moscow (Russian Federation); Radecka, Hanna [Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, Tuwima 10, 10-747 Olsztyn (Poland); Radecki, Jerzy [Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, Tuwima 10, 10-747 Olsztyn (Poland)], E-mail: radecki@pan.olsztyn.pl

    2009-09-30

    Molecular electronics has been associated with high density nano-electronic devices. Developments of molecular electronic devices were based on reversible switching of molecules between the two conductive states. In this paper, self-assembled monolayers of dodecanethiol (DDT) and thiol tethered iron(II)clathrochelate (IC) have been prepared on gold film. The electrochemical and electronic properties of IC molecules inserted into the dodecanethiol monolayer (IC-DDT SAM) were investigated using voltammetric, electrochemical impedance spectroscopy (EIS), scanning tunneling microscopy (STM) and cross-wire tunneling measurements. The voltage triggered switching behaviour of IC molecules on mixed SAM was demonstrated. Deposition of polyaniline on the redox sites of IC-DDT SAM using electrochemical polymerization of aniline was performed in order to confirm that this monolayer acts as nano-patterned semiconducting electrode surface.

  6. A compact plasmonic MOS-based 2×2 electro-optic switch

    Directory of Open Access Journals (Sweden)

    Ye Chenran

    2015-01-01

    Full Text Available We report on a three-waveguide electro-optic switch for compact photonic integrated circuits and data routing applications. The device features a plasmonic metal-oxide-semiconductor (MOS mode for enhanced light-matter-interactions. The switching mechanism originates from a capacitor-like design where the refractive index of the active medium, indium-tin-oxide, is altered via shifting the plasma frequency due to carrier accumulation inside the waveguide-based MOS structure. This light manipulation mechanism controls the transmission direction of transverse magnetic polarized light into either a CROSS or BAR waveguide port. The extinction ratio of 18 (7 dB for the CROSS (BAR state, respectively, is achieved via a gating voltage bias. The ultrafast broadband fJ/bit device allows for seamless integration with silicon-on-insulator platforms for low-cost manufacturing.

  7. Low-field Switching Four-state Nonvolatile Memory Based on Multiferroic Tunnel Junctions

    Science.gov (United States)

    Yau, H. M.; Yan, Z. B.; Chan, N. Y.; Au, K.; Wong, C. M.; Leung, C. W.; Zhang, F. Y.; Gao, X. S.; Dai, J. Y.

    2015-08-01

    Multiferroic tunneling junction based four-state non-volatile memories are very promising for future memory industry since this kind of memories hold the advantages of not only the higher density by scaling down memory cell but also the function of magnetically written and electrically reading. In this work, we demonstrate a success of this four-state memory in a material system of NiFe/BaTiO3/La0.7Sr0.3MnO3 with improved memory characteristics such as lower switching field and larger tunneling magnetoresistance (TMR). Ferroelectric switching induced resistive change memory with OFF/ON ratio of 16 and 0.3% TMR effect have been achieved in this multiferroic tunneling structure.

  8. Experimental and theoretical investigation of semiconductor optical amplifier (SOA) based all-optical switches

    DEFF Research Database (Denmark)

    Nielsen, Mads Lønstrup

    2004-01-01

    This thesis analyzes semiconductor optical amplifier (SOA) based all-optical switches experimentally and through numerical simulations. These devices are candidates for optical signal processing functionalities such as wavelength conversion, regeneration, and logic processing in future transparent......, consisting of an SOA and an asymmetric MZI filter, is analyzed in the small-signal regime, and the obtainable modulation bandwidth is expressed analytically. A new optical spectrum approach to small signal analysis is introduced, and is used to assess the bandwidth enhancing effect of different optical...... filters, as well the impact of the filter phase response. Experiments at 40 Gb/s verify the predictions of the small-signal analysis. Wavelength conversion is demonstrated experimentally at 40 Gb/s using a simple filtering-assisted scheme with an ultra-low optical switching energy, and up to 80 Gb...

  9. Optimization of Contact Force and Pull-in Voltage for Series based MEMS Switch

    Directory of Open Access Journals (Sweden)

    Abhijeet KSHIRSAGAR

    2010-04-01

    Full Text Available Cantilever based metal-to-metal contact type MEMS series switch has many applications namely in RF MEMS, Power MEMS etc. A typical MEMS switch consists of a cantilever as actuating element to make the contact between the two metal terminals of the switch. The cantilever is pulled down by applying a pull-in voltage to the control electrode that is located below the middle portion of the cantilever while only the tip portion of the cantilever makes contact between the two terminals. Detailed analysis of bending of the cantilever for different pull-in voltages reveals some interesting facts. At low pull-in voltage the cantilever tip barely touches the two terminals, thus resulting in very less contact area. To increase contact area a very high pull-in voltage is applied, but it lifts the tip from the free end due to concave curving of the cantilever in the middle region of the cantilever where the electrode is located. Again it results in less contact area. Furthermore, the high pull-in voltage produces large stress at the base of the cantilever close to the anchor. Therefore, an optimum, pull-in voltage must exist at which the concave curving is eliminated and contact area is maximum. In this paper authors report the finding of optimum contact force and pull-in voltage.

  10. Kinetics of Domain Switching by Mechanical and Electrical Stimulation in Relaxor-Based Ferroelectrics

    Science.gov (United States)

    Chen, Zibin; Hong, Liang; Wang, Feifei; An, Xianghai; Wang, Xiaolin; Ringer, Simon; Chen, Long-Qing; Luo, Haosu; Liao, Xiaozhou

    2017-12-01

    Ferroelectric materials have been extensively explored for applications in high-density nonvolatile memory devices because of their ferroelectric-ferroelastic domain-switching behavior under electric loading or mechanical stress. However, the existence of ferroelectric and ferroelastic backswitching would cause significant data loss, which affects the reliability of data storage. Here, we apply in situ transmission electron microscopy and phase-field modeling to explore the unique ferroelastic domain-switching kinetics and the origin of this in relaxor-based Pb (Mg1 /3Nb2 /3)O3-33 % PbTiO3 single-crystal pillars under electrical and mechanical stimulations. Results showed that the electric-mechanical hysteresis loop shifted for relaxor-based single-crystal pillars because of the low energy levels of domains in the material and the constraint on the pillars, resulting in various mechanically reversible and irreversible domain-switching states. The phenomenon can potentially be used for advanced bit writing and reading in nonvolatile memories, which effectively overcomes the backswitching problem and broadens the types of ferroelectric materials for nonvolatile memory applications.

  11. Bluetooth-based wireless sensor networks

    Science.gov (United States)

    You, Ke; Liu, Rui Qiang

    2007-11-01

    In this work a Bluetooth-based wireless sensor network is proposed. In this bluetooth-based wireless sensor networks, information-driven star topology and energy-saved mode are used, through which a blue master node can control more than seven slave node, the energy of each sensor node is reduced and secure management of each sensor node is improved.

  12. A high‐isolation switch based on a standard GaAs process

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy

    2011-01-01

    The design and evaluation of an ultra‐wideband nonreflective single port single throw switch integrated circuit is described. The switch has a measured insertion loss of......The design and evaluation of an ultra‐wideband nonreflective single port single throw switch integrated circuit is described. The switch has a measured insertion loss of...

  13. A graphite based STT-RAM cell with reduction in switching current

    International Nuclear Information System (INIS)

    Varghani, Ali; Peiravi, Ali

    2015-01-01

    Spin Transfer Torque Random Access Memory (STT-RAM) is a serious candidate for “universal memory” because of its non-volatility, fast access time, high density, good scalability, high endurance and relatively low power dissipation. However, problems with low write speed and large write current are important existing challenges in STT-RAM design and there is a tradeoff between them and data retention time. In this study, a novel STT-RAM cell structure which uses perfect graphite based Magnetic Tunnel Junction (MTJ) is proposed. First, the cross-section of the structure is selected to be an ellipse of 45 nm and 180 nm dimensions and a six-layer graphite is used as tunnel barrier. By passing a lateral current with a short pulse width (before applying STT current and independent of it) through four middle graphene layers of the tunnel barrier, a 27% reduction in the amplitude of the switching current (for fast switching time of 2 ns) or a 58% reduction in its pulse width is achieved without any reduction in data retention time. Finally, the effect of downscaling of technology on the proposed structure is evaluated. A reduction of 31.6% and 9% in switching current is achieved for 90 and 22 nm cell width respectively by passing sufficient current (100 µA with 0.1 ns pulse width) through the tunnel barrier. Simulations are done using Object Oriented Micro Magnetic Framework (OOMMF). - Highlights: • A new STT-RAM cell structure which uses perfect graphite based MTJ is proposed. • The amplitude of the switching current or its pulsewidth can be reduced without any sacrifice of data retention time. • The proposed design is down-scalable from 90 nm to 22 nm. • Micromagnetic simulations are done with OOMMF

  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

    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...... 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...

  15. Phase-controlled all-optical switching based on coherent population oscillation in a two-level system

    International Nuclear Information System (INIS)

    Liao, Ping; Yu, Song; Luo, Bin; Shen, Jing; Gu, Wanyi; Guo, Hong

    2011-01-01

    We theoretically propose a scheme of phase-controlled all-optical switching due to the effect of degenerate four-wave mixing (FWM) and coherent population oscillation (CPO) in a two-level system driven by a strong coupling field and two weak symmetrically detuned fields. The results show that the phase of the FWM field can be utilized to switch between constructive and destructive interference, which can lead to the transmission or attenuation of the probe field and thus switch the field on or off. We also find the intensity of the coupling field and the propagation distance have great influence on the performance of the switching. In our scheme, due to the quick response in semiconductor systems, a fast all-optical switching can be realized at low light level. -- Highlights: ► We study a new all-optical switching based on coherent population oscillation. ► The phase of the FWM field can be utilized to switch the probe field on or off. ► A fast and low-light-level switching can be realized in semiconductors.

  16. Memristor-based neural networks

    International Nuclear Information System (INIS)

    Thomas, Andy

    2013-01-01

    The synapse is a crucial element in biological neural networks, but a simple electronic equivalent has been absent. This complicates the development of hardware that imitates biological architectures in the nervous system. Now, the recent progress in the experimental realization of memristive devices has renewed interest in artificial neural networks. The resistance of a memristive system depends on its past states and exactly this functionality can be used to mimic the synaptic connections in a (human) brain. After a short introduction to memristors, we present and explain the relevant mechanisms in a biological neural network, such as long-term potentiation and spike time-dependent plasticity, and determine the minimal requirements for an artificial neural network. We review the implementations of these processes using basic electric circuits and more complex mechanisms that either imitate biological systems or could act as a model system for them. (topical review)

  17. Community Based Networks and 5G

    DEFF Research Database (Denmark)

    Williams, Idongesit

    2016-01-01

    The deployment of previous wireless standards has provided more benefits for urban dwellers than rural dwellers. 5G deployment may not be different. This paper identifies that Community Based Networks as carriers that deserve recognition as potential 5G providers may change this. The argument....... The findings indicate that 5G connectivity can be extended to rural areas by these networks, via heterogenous networks. Hence the delivery of 5G data rates delivery via Wireless WAN in rural areas can be achieved by utilizing the causal factors of the identified models for Community Based Networks....

  18. A novel SDN enabled hybrid oiptical packet/circuit switched data centre network - The LIGHTNESS approach

    NARCIS (Netherlands)

    Peng, S.; Simeonidou, D.; Zervas, G.; Nejabati, R.; Yan, Y; Shu, Yi; Spadaro, S.; Perelló, J.; Agraz, F.; Careglio, D.; Dorren, H.J.S.; Miao, W.; Calabretta, N.; Bernini, G.; Ciulli, N.; Sancho, J.C.; Iordache, S.; Becerra, Y.; Farreras, M.; Biancani, M.; Predieri, A.; Proietti, R.; Cao, Z.; Liu, L.; Yoo, S.J.B.

    2014-01-01

    Current over-provisioned and multi-tier data centre networks (DCN) deploy rigid control and management platforms, which are not able to accommodate the ever-growing workload driven by the increasing demand of high-performance data centre (DC) and cloud applications. In response to this, the EC FP7

  19. An Energy-Efficient Reconfigurable Circuit Switched Network-on-Chip

    NARCIS (Netherlands)

    Wolkotte, P.T.; Smit, Gerardus Johannes Maria; Rauwerda, G.K.; Smit, L.T.

    Network-on-Chip (NoC) is an energy-efficient on-chip communication architecture for multi-tile System-on-Chip (SoC) architectures. The SoC architecture, including its run-time software, can replace inflexible ASICs for future ambient systems. These ambient systems have to be flexible as well as

  20. Activity-dependent switch of GABAergic inhibition into glutamatergic excitation in astrocyte-neuron networks.

    Science.gov (United States)

    Perea, Gertrudis; Gómez, Ricardo; Mederos, Sara; Covelo, Ana; Ballesteros, Jesús J; Schlosser, Laura; Hernández-Vivanco, Alicia; Martín-Fernández, Mario; Quintana, Ruth; Rayan, Abdelrahman; Díez, Adolfo; Fuenzalida, Marco; Agarwal, Amit; Bergles, Dwight E; Bettler, Bernhard; Manahan-Vaughan, Denise; Martín, Eduardo D; Kirchhoff, Frank; Araque, Alfonso

    2016-12-24

    Interneurons are critical for proper neural network function and can activate Ca 2+ signaling in astrocytes. However, the impact of the interneuron-astrocyte signaling into neuronal network operation remains unknown. Using the simplest hippocampal Astrocyte-Neuron network, i.e., GABAergic interneuron, pyramidal neuron, single CA3-CA1 glutamatergic synapse, and astrocytes, we found that interneuron-astrocyte signaling dynamically affected excitatory neurotransmission in an activity- and time-dependent manner, and determined the sign (inhibition vs potentiation) of the GABA-mediated effects. While synaptic inhibition was mediated by GABA A receptors, potentiation involved astrocyte GABA B receptors, astrocytic glutamate release, and presynaptic metabotropic glutamate receptors. Using conditional astrocyte-specific GABA B receptor ( Gabbr1 ) knockout mice, we confirmed the glial source of the interneuron-induced potentiation, and demonstrated the involvement of astrocytes in hippocampal theta and gamma oscillations in vivo. Therefore, astrocytes decode interneuron activity and transform inhibitory into excitatory signals, contributing to the emergence of novel network properties resulting from the interneuron-astrocyte interplay.

  1. 47 CFR 68.110 - Compatibility of the public switched telephone network and terminal equipment.

    Science.gov (United States)

    2010-10-01

    ... changes in its communications facilities, equipment, operations or procedures, where such action is... in this part. If such changes can be reasonably expected to render any customer's terminal equipment... network and terminal equipment. 68.110 Section 68.110 Telecommunication FEDERAL COMMUNICATIONS COMMISSION...

  2. Stability switches, oscillatory multistability, and spatio-temporal patterns of nonlinear oscillations in recurrently delay coupled neural networks.

    Science.gov (United States)

    Song, Yongli; Makarov, Valeri A; Velarde, Manuel G

    2009-08-01

    A model of time-delay recurrently coupled spatially segregated neural assemblies is here proposed. We show that it operates like some of the hierarchical architectures of the brain. Each assembly is a neural network with no delay in the local couplings between the units. The delay appears in the long range feedforward and feedback inter-assemblies communications. Bifurcation analysis of a simple four-units system in the autonomous case shows the richness of the dynamical behaviors in a biophysically plausible parameter region. We find oscillatory multistability, hysteresis, and stability switches of the rest state provoked by the time delay. Then we investigate the spatio-temporal patterns of bifurcating periodic solutions by using the symmetric local Hopf bifurcation theory of delay differential equations and derive the equation describing the flow on the center manifold that enables us determining the direction of Hopf bifurcations and stability of the bifurcating periodic orbits. We also discuss computational properties of the system due to the delay when an external drive of the network mimicks external sensory input.

  3. Managing the PSTN transformation a blueprint for a successful migration to IP-based networks

    CERN Document Server

    Dornheim, Sandra

    2015-01-01

    While there are many scholarly books and papers that cover the technical issues behind the public switched telephone network (PSTN) migration, few books describe exactly how to manage the migration process economically. Filling this need, Managing the PSTN Transformation: A Blueprint for a Successful Migration to IP-Based Networks reflects the latest understanding of the challenges behind migrating customers from the old PSTN network to an IP infrastructure. The IP transformation blueprint described in this book is not a theoretical cookbook that describes how this could work. Instead, the boo

  4. A New Time Calibration Method for Switched-capacitor-array-based Waveform Samplers.

    Science.gov (United States)

    Kim, H; Chen, C-T; Eclov, N; Ronzhin, A; Murat, P; Ramberg, E; Los, S; Moses, W; Choong, W-S; Kao, C-M

    2014-12-11

    We have developed a new time calibration method for the DRS4 waveform sampler that enables us to precisely measure the non-uniform sampling interval inherent in the switched-capacitor cells of the DRS4. The method uses the proportionality between the differential amplitude and sampling interval of adjacent switched-capacitor cells responding to a sawtooth-shape pulse. In the experiment, a sawtooth-shape pulse with a 40 ns period generated by a Tektronix AWG7102 is fed to a DRS4 evaluation board for calibrating the sampling intervals of all 1024 cells individually. The electronic time resolution of the DRS4 evaluation board with the new time calibration is measured to be ~2.4 ps RMS by using two simultaneous Gaussian pulses with 2.35 ns full-width at half-maximum and applying a Gaussian fit. The time resolution dependencies on the time difference with the new time calibration are measured and compared to results obtained by another method. The new method could be applicable for other switched-capacitor-array technology-based waveform samplers for precise time calibration.

  5. A graphite based STT-RAM cell with reduction in switching current

    Science.gov (United States)

    Varghani, Ali; Peiravi, Ali

    2015-10-01

    Spin Transfer Torque Random Access Memory (STT-RAM) is a serious candidate for "universal memory" because of its non-volatility, fast access time, high density, good scalability, high endurance and relatively low power dissipation. However, problems with low write speed and large write current are important existing challenges in STT-RAM design and there is a tradeoff between them and data retention time. In this study, a novel STT-RAM cell structure which uses perfect graphite based Magnetic Tunnel Junction (MTJ) is proposed. First, the cross-section of the structure is selected to be an ellipse of 45 nm and 180 nm dimensions and a six-layer graphite is used as tunnel barrier. By passing a lateral current with a short pulse width (before applying STT current and independent of it) through four middle graphene layers of the tunnel barrier, a 27% reduction in the amplitude of the switching current (for fast switching time of 2 ns) or a 58% reduction in its pulse width is achieved without any reduction in data retention time. Finally, the effect of downscaling of technology on the proposed structure is evaluated. A reduction of 31.6% and 9% in switching current is achieved for 90 and 22 nm cell width respectively by passing sufficient current (100 μA with 0.1 ns pulse width) through the tunnel barrier. Simulations are done using Object Oriented Micro Magnetic Framework (OOMMF).

  6. Cross entropy-based memetic algorithms: An application study over the tool switching problem

    Directory of Open Access Journals (Sweden)

    Jhon Edgar Amaya

    2013-05-01

    Full Text Available This paper presents a parameterized schema for building memetic algorithms based on cross-entropy (CE methods. This novel schema is general in nature, and features multiple probability mass functions and Lamarckian learning. The applicability of the approach is assessed by considering the Tool Switching Problem, a complex combinatorial problem in the field of Flexible Manufacturing Systems. An exhaustive evaluation (including techniques ranging from local search and evolutionary algorithms to constructive methods provides evidence of the effectiveness of CE-based memetic algorithms.

  7. Synchronising chaotic Chua's circuit using switching feedback control based on piecewise quadratic Lyapunov functions

    International Nuclear Information System (INIS)

    Hong-Bin, Zhang; Jian-Wei, Xia; Yong-Bin, Yu; Chuang-Yin, Dang

    2010-01-01

    This paper investigates the chaos synchronisation between two coupled chaotic Chua's circuits. The sufficient condition presented by linear matrix inequalities (LMIs) of global asymptotic synchronisation is attained based on piecewise quadratic Lyapunov functions. First, we obtain the piecewise linear differential inclusions (pwLDIs) model of synchronisation error dynamics, then we design a switching (piecewise-linear) feedback control law to stabilise it based on the piecewise quadratic Laypunov functions. Then we give some numerical simulations to demonstrate the effectiveness of our theoretical results

  8. Analysis and modeling of resistive switching mechanism oriented to fault tolerance of resistive memory based on memristor

    International Nuclear Information System (INIS)

    Huang Da; Wu Jun-Jie; Tang Yu-Hua

    2014-01-01

    With the progress of the semiconductor industry, resistive memories, especially the memristor, have drawn increasing attention. The resistive memory based on memrsitor has not been commercialized mainly because of data error. Currently, there are more studies focused on fault tolerance of resistive memory. This paper studies the resistive switching mechanism which may have time-varying characteristics. Resistive switching mechanism is analyzed and its respective circuit model is established based on the memristor Spice model

  9. Cut Based Method for Comparing Complex Networks.

    Science.gov (United States)

    Liu, Qun; Dong, Zhishan; Wang, En

    2018-03-23

    Revealing the underlying similarity of various complex networks has become both a popular and interdisciplinary topic, with a plethora of relevant application domains. The essence of the similarity here is that network features of the same network type are highly similar, while the features of different kinds of networks present low similarity. In this paper, we introduce and explore a new method for comparing various complex networks based on the cut distance. We show correspondence between the cut distance and the similarity of two networks. This correspondence allows us to consider a broad range of complex networks and explicitly compare various networks with high accuracy. Various machine learning technologies such as genetic algorithms, nearest neighbor classification, and model selection are employed during the comparison process. Our cut method is shown to be suited for comparisons of undirected networks and directed networks, as well as weighted networks. In the model selection process, the results demonstrate that our approach outperforms other state-of-the-art methods with respect to accuracy.

  10. 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.

  11. Adsorption and switching properties of a N-benzylideneaniline based molecular switch on a Au(111) surface

    International Nuclear Information System (INIS)

    Ovari, Laszlo; Luo, Ying; Haag, Rainer; Leyssner, Felix; Tegeder, Petra; Wolf, Martin

    2010-01-01

    High resolution electron energy loss spectroscopy has been employed to analyze the adsorption geometry and the photoisomerization ability of the molecular switch carboxy-benzylideneaniline (CBA) adsorbed on Au(111). CBA on Au(111) adopts a planar (trans) configuration in the first monolayer (ML) as well as for higher coverages (up to 6 ML), in contrast to the strongly nonplanar geometry of the molecule in solution. Illumination with UV light of CBA in direct contact with the Au(111) surface (≤1 ML) caused no changes in the vibrational structure, whereas at higher coverages (>1 ML) pronounced modifications of vibrational features were observed, which we assign to a trans→cis isomerization. Thermal activation induced the back reaction to trans-CBA. We propose that the photoisomerization is driven by a direct (intramolecular) electronic excitation of the adsorbed CBA molecules in the second ML (and above) analogous to CBA in the liquid phase.

  12. Energy-Based Adaptive Sliding Mode Speed Control for Switched Reluctance Motor Drive

    Directory of Open Access Journals (Sweden)

    M. M. Namazi Isfahani

    2012-03-01

    Full Text Available Torque ripple minimization of switched reluctance motor drives is a major subject based on these drives’ extensive use in the industry. In this paper, by using a well-known cascaded torque control structure and taking the machine physical structure characteristics into account, the proposed energy-based (passivity-based adaptive sliding algorithm derived from the view point of energy dissipation, control stability and algorithm robustness. First, a nonlinear dynamic model is developed and decomposed into separate slow and fast passive subsystems which are interconnected by negative feedbacks. Then, an outer loop speed control is employed by adaptive sliding controller to determine the appropriate torque command. Finally, to reduce torque ripple in switched reluctance motor a high-performance passivity-based current controller is proposed. It can overcome the inherent nonlinear characteristics of the system and make the whole system robust to uncertainties and bounded disturbances. The performance of the proposed controller algorithm has been demonstrated in simulation, and experimental using a 4KW, four-phase, 8/6 pole SRM DSP-based drive system.

  13. Network-based Approaches in Pharmacology.

    Science.gov (United States)

    Boezio, Baptiste; Audouze, Karine; Ducrot, Pierre; Taboureau, Olivier

    2017-10-01

    In drug discovery, network-based approaches are expected to spotlight our understanding of drug action across multiple layers of information. On one hand, network pharmacology considers the drug response in the context of a cellular or phenotypic network. On the other hand, a chemical-based network is a promising alternative for characterizing the chemical space. Both can provide complementary support for the development of rational drug design and better knowledge of the mechanisms underlying the multiple actions of drugs. Recent progress in both concepts is discussed here. In addition, a network-based approach using drug-target-therapy data is introduced as an example. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. CONTROL OF BOUNCING IN RF MEMS SWITCHES USING DOUBLE ELECTRODE

    KAUST Repository

    Abdul Rahim, Farhan

    2014-01-01

    MEMS based mechanical switches are seen to be the likely replacements for CMOS based switches due to the several advantages that these mechanical switches have over CMOS switches. Mechanical switches can be used in systems under extreme conditions

  15. Cognitive Radio-based Home Area Networks

    NARCIS (Netherlands)

    Sarijari, M.A.B.

    2016-01-01

    A future home area network (HAN) is envisaged to consist of a large number of devices that support various applications such as smart grid, security and safety systems, voice call, and video streaming. Most of these home devices are communicating based on various wireless networking technologies

  16. VLSI Based Multiprocessor Communications Networks.

    Science.gov (United States)

    1982-09-01

    Networks". The contract began on September 1,1980 and was approved on scientific /technical grounds for a duration of three years. Incremental funding was...values for the individual delays will vary from comunicating modules (ij) are shown in Figure 4 module to module due to processing and fabrication

  17. Distribution network topology identification based on synchrophasor

    Directory of Open Access Journals (Sweden)

    Stefania Conti

    2018-03-01

    Full Text Available A distribution system upgrade moving towards Smart Grid implementation is necessary to face the proliferation of distributed generators and electric vehicles, in order to satisfy the increasing demand for high quality, efficient, secure, reliable energy supply. This perspective requires taking into account system vulnerability to cyber attacks. An effective attack could destroy stored information about network structure, historical data and so on. Countermeasures and network applications could be made impracticable since most of them are based on the knowledge of network topology. Usually, the location of each link between nodes in a network is known. Therefore, the methods used for topology identification determine if a link is open or closed. When no information on the location of the network links is available, these methods become totally unfeasible. This paper presents a method to identify the network topology using only nodal measures obtained by means of phasor measurement units.

  18. Modeling the interdependent network based on two-mode networks

    Science.gov (United States)

    An, Feng; Gao, Xiangyun; Guan, Jianhe; Huang, Shupei; Liu, Qian

    2017-10-01

    Among heterogeneous networks, there exist obviously and closely interdependent linkages. Unlike existing research primarily focus on the theoretical research of physical interdependent network model. We propose a two-layer interdependent network model based on two-mode networks to explore the interdependent features in the reality. Specifically, we construct a two-layer interdependent loan network and develop several dependent features indices. The model is verified to enable us to capture the loan dependent features of listed companies based on loan behaviors and shared shareholders. Taking Chinese debit and credit market as case study, the main conclusions are: (1) only few listed companies shoulder the main capital transmission (20% listed companies occupy almost 70% dependent degree). (2) The control of these key listed companies will be more effective of avoiding the spreading of financial risks. (3) Identifying the companies with high betweenness centrality and controlling them could be helpful to monitor the financial risk spreading. (4) The capital transmission channel among Chinese financial listed companies and Chinese non-financial listed companies are relatively strong. However, under greater pressure of demand of capital transmission (70% edges failed), the transmission channel, which constructed by debit and credit behavior, will eventually collapse.

  19. Synchronization of stochastic delayed neural networks with markovian switching and its application.

    Science.gov (United States)

    Tang, Yang; Fang, Jian-An; Miao, Qing-Ying

    2009-02-01

    In this paper, the problem of adaptive synchronization for a class of stochastic neural networks (SNNs) which involve both mixed delays and Markovian jumping parameters is investigated. The mixed delays comprise the time-varying delays and distributed delays, both of which are mode-dependent. The stochastic perturbations are described in terms of Browian motion. By the adaptive feedback technique, several sufficient criteria have been proposed to ensure the synchronization of SNNs in mean square. Moreover, the proposed adaptive feedback scheme is applied to the secure communication. Finally, the corresponding simulation results are given to demonstrate the usefulness of the main results obtained.

  20. Resistive switching in ZrO{sub 2} based metal-oxide-metal structures

    Energy Technology Data Exchange (ETDEWEB)

    Kaerkkaenen, Irina

    2014-07-01

    detail for 20 nm thick ZrO{sub 2} films grown by an ozone based ALD process and integrated into Pt/ZrO{sub 2}/Ti/Pt cells while the thickness of the electrochemically active electrode (Ti) was varied from 0 nm to 40 nm. Cells with a thin EAE (<20 nm Ti) exhibited a UP-type RS behavior, while cells with thick EAE (>20 nm Ti) showed BP switching characteristics at a lower current compliance as the UP switching cells. A detailed structural analysis of the ozone grown ZrO{sub 2} films revealed a polycrystalline structure of columnar shaped grains with a meta-stable cubic-tetragonal ZrO{sub 2} phase. In the second part of the thesis an empirical model for the polarity dependence of the RS in the ALD ZrO{sub 2} based devices as a function of the EAE thickness was suggested. The model assumed a columnar shaped microstructure and certain impurity content for the ZrO{sub 2} films. In addition, the results of current-voltage behavior, temperature dependency of the resistance states and impedance spectroscopy (IS) measurements of different devices in different RS states were considered. Impedance spectroscopy measurements of UP and BP type switching devices with the same ZrO{sub 2} films but with different EAE thicknesses were carried out for the states prior to electroforming (pristine), after RS into the ON-state and after RS into the OFF-state. The different devices in their pristine states exhibited nearly identical IS characteristics while the ON and OFF states of the UP and BP devices revealed pronounced differences. In the model, the UP switching in ZrO{sub 2} based devices with thin EAE was described as a result of a noncomplete local reduction of the grain boundary cores, which might gave rise to a hard thermal breakdown and the formation of metallic like conduction paths. On the contrary, the suggested idea for BP switching of ZrO{sub 2} based devices with thick EAE based on the formation of local semiconducting oxygen depleted ZrO{sub 2-x} filament-like regions along

  1. Resistive switching in ZrO2 based metal-oxide-metal structures

    International Nuclear Information System (INIS)

    Kaerkkaenen, Irina

    2014-01-01

    The goal of this work is a deeper understanding of the influence of the (i) metal-oxide-metal (MOM) layer stacks configuration, (ii) the oxide films microstructure, (iii) and their defect structure on the appearance of different switching modes, i.e. unipolar (UP) and bipolar (BP). The first part deals with the fabrication of ZrO 2 thin films by an industrial compatible atomic layer deposition (ALD) process, the chemical, structural and morphological characterization of the films, the growth of ZrO 2 /TiO 2 bilayers, the integration of the layers into metal-oxide-metal (MOM) devices and the electrical characterization with focus on the RS behavior. In the second part the effect of the device structure, in particular the thickness of the electrochemical active electrode (EAE) and the ZrO 2 film morphology, on the RS switching polarity of Pt/ZrO 2 /(EAE) cells is discussed. ZrO 2 films and ZrO 2 /TiO 2 bilayers were grown by ALD and were carefully structurally and electrically characterized. The ZrO 2 films grown from Zr[N(CH 3 )C 2 H 5 ] 4 (TEMA-Zr) at 240 C were polycrystalline with a mixture of cubic/tetragonal phases. ALD/H 2 O-ZrO 2 films exhibited a random oriented polycrystalline structure, whereas the ALD/O 3 -ZrO 2 films consisted of preferably oriented cubic shaped grains. Pt/ZrO 2 /Ti/Pt structures with a Ti top electrode (TE) thickness of 5 to 20 nm showed unipolar type RS behavior, while by increasing the Ti TE thickness a gradual change of switching polarity from unipolar to bipolar with a completely bipolar type RS behavior for a Ti TE thickness of 40 nm is found. The switching in Pt/ZrO 2 /TiO 2 /Ti/Pt devices was unipolar, comparable to Pt/ZrO 2 /Ti/Pt cells. In contrast, bilayers with the reverse structure, Pt/TiO 2 /ZrO 2 /Ti/Pt, showed non-switching behavior. The effect of the cells stack structure on the polarity of the RS behavior was studied in detail for 20 nm thick ZrO 2 films grown by an ozone based ALD process and integrated into Pt/ZrO 2

  2. Plasmonic Switches and Sensors Based on PANI-Coated Gold Nanostructures

    Science.gov (United States)

    Jiang, Nina

    shift. Based on this principle, I have fabricated (gold nanosphere core)/(oxidized PANI shell) plasmonic sensors. The sensors have great potential for sensing chemical and biological molecules with reducibility. By using ascorbic acid (AA) as a target analyte, the plasmonic sensor presents high sensing capability. The limit of detection is 0.5 muM, and the linear response range is from 0.5 muM to 10 muM. The limit of detection for my plasmonic sensor is lower than the lowest limit for AA sensors based on liquid chromatography, electrophoresis, and electrochemical method. The sensing performance of my plasmonic sensors is expected to be further improved by optimizing the amount of (gold nanosphere core)/(oxidized PANI shell) structures, or employing other gold nanostructures with higher refractive index sensitivities. I believe that the colloidal (metal core)/(PANI shell) nanostructures pave the way for the fabrication of high-performance, low-cost plasmonic switches as well as for the preparation of advanced, programmable chromic materials for a wide variety of applications, such as smart windows, military anti-counterfeiting and camouflage, environmental sensors and indicators. (Abstract shortened by UMI.).

  3. Graphene Oxide-Based Q-Switched Erbium-Doped Fiber Laser

    International Nuclear Information System (INIS)

    Yap, Y. K.; Harun, S. W.; Ahmad, H.; Huang, N. M.

    2013-01-01

    We demonstrate a pulsed ring erbium-doped fiber laser based on graphene oxide (GO), employing a simplified Hummer's method to synthesize the GO via chemical oxidation of graphite flakes at room temperature. By dipping a fiber ferrule end face onto the GO suspension, GO is successfully coated onto the end face, making it a simple saturable absorption device. A stable Q-switched pulsed fiber laser is achieved with a low pump threshold of 9.5 mW at 980 nm. The pulse repetition rate ranges from 16.0 to 57.0 kHz. The pulse width and the pulse energy are studied and discussed

  4. Switch Based Opportunistic Spectrum Access for General Primary User Traffic Model

    KAUST Repository

    Gaaloul, Fakhreddine

    2012-06-18

    This letter studies cognitive radio transceiver that can opportunistically use the available channels of primary user (PU). Specifically, we investigate and compare two different opportunistic channel access schemes. The first scheme applies when the secondary user (SU) has access to only one channel. The second scheme, based on channel switching mechanism, applies when the SU has access to multiple channels but can at a given time monitor and access only one channel. For these access schemes, we derive the exact analytical results for the novel performance metrics of average access time and average waiting time under general PU traffic models.

  5. GaN-based High Efficiency Bidirectional DC-DC Converter with 10 MHz Switching Frequency

    DEFF Research Database (Denmark)

    Kruse, Kristian; Zhang, Zhe; Elbo, Mads

    2017-01-01

    -isolated bidirectional DC-DC converter equipped with Gallium Nitride (GaN) semiconductor transistors is presented. The converter’s operation principles, zero-voltage switching (ZVS) constraints and dead-time effects are studied. Moreover, the optimization and tradeoffs on the adopted high-frequency inductor...... are achieved. Moreover, the measured losses can match the theoretically calculated counterparts well, therefore the design and analysis are verified. However, from the experimental test carried out, it can also be seen, that making a compact converter, even for a GaN-based one, operate at 10 MHz and 100 W...

  6. Switch Based Opportunistic Spectrum Access for General Primary User Traffic Model

    KAUST Repository

    Gaaloul, Fakhreddine; Alouini, Mohamed-Slim; Radaydeh, Redha M.; Yang, Hong-Chuan

    2012-01-01

    This letter studies cognitive radio transceiver that can opportunistically use the available channels of primary user (PU). Specifically, we investigate and compare two different opportunistic channel access schemes. The first scheme applies when the secondary user (SU) has access to only one channel. The second scheme, based on channel switching mechanism, applies when the SU has access to multiple channels but can at a given time monitor and access only one channel. For these access schemes, we derive the exact analytical results for the novel performance metrics of average access time and average waiting time under general PU traffic models.

  7. A microcontroller-based compensated optical proximity detector employing the switching-mode synchronous detection technique

    International Nuclear Information System (INIS)

    Rakshit, Anjan; Chatterjee, Amitava

    2012-01-01

    This paper describes the development of a microcontroller-based optical proximity detector that can provide a low-cost yet powerful obstacle-sensing mechanism for mobile robots. The system is developed with the switching-mode synchronous detection technique to provide satisfactory performance over a wide range of operating conditions and is developed with the facility of externally setting a threshold, for reliable operation. The system is dynamically compensated against ambient illumination variations. Experimental studies demonstrate how the minimum distance of activation can be varied with different choices of thresholds. (paper)

  8. Implementasi Wireless Quality of Service dengan Metode Load Switching Jaringan Seluler Menggunakan Software Defined Network untuk Meningkatkan Network Reliability pada Jaringan Dinamis

    Directory of Open Access Journals (Sweden)

    Yoga Bayu Aji Pranawa

    2017-03-01

    Full Text Available Wireless Quality of Service (QOS adalah salah satu dimensi mobilitas, yaitu sebuah metode yang digunakan untuk menjaga kualitas suatu jaringan nirkabel. QOS diperlukan sebagai sebuah metode untuk memenuhi kriteria pelayanan sistem bagi pengguna, yaitu confidentiality, integrity, dan availability. Beberapa aspek yang menjadi topik utama dalam QOS adalah failure and recovery mechanism, variable bandwidth, computing distribution, discovery mechanism, variable lantency, dan performance feedback. Wireless yang dibahas pada penelitian ini dititik beratkan pada jaringan seluler yang cenderung tidak reliable pada daerah tertentu. Oleh karena itu dibutuhkan sebuah mekanisme yang dapat mengatasi tidak stabilnya jaringan seluler tersebut. mplementasi mekanisme yang diterapkan pada penelitian ini adalah dengan menerapkan load switching pada jaringan seluler dengan menggunakan beberapa provider dan menerapkan teknologi Software Defined Network (SDN. Berdasarkan hasi uji coba dapat disimpulkan bahwa sistem yang dibuat pada penelitian ini dapat menerapkan wireless quality of service dan meningkatkan network reliability sebesar 65,29% dan 83,87% lebih baik untuk penggunaan tanpa waktu tunggu dan dengan waktu tunggu pada suatu jaringan  dinamis.

  9. MOBS - A modular on-board switching system

    Science.gov (United States)

    Berner, W.; Grassmann, W.; Piontek, M.

    The authors describe a multibeam satellite system that is designed for business services and for communications at a high bit rate. The repeater is regenerative with a modular onboard switching system. It acts not only as baseband switch but also as the central node of the network, performing network control and protocol evaluation. The hardware is based on a modular bus/memory architecture with associated processors.

  10. Autonomous power networks based power system

    International Nuclear Information System (INIS)

    Jokic, A.; Van den Bosch, P.P.J.

    2006-01-01

    This paper presented the concept of autonomous networks to cope with this increased complexity in power systems while enhancing market-based operation. The operation of future power systems will be more challenging and demanding than present systems because of increased uncertainties, less inertia in the system, replacement of centralized coordinating activities by decentralized parties and the reliance on dynamic markets for both power balancing and system reliability. An autonomous network includes the aggregation of networked producers and consumers in a relatively small area with respect to the overall system. The operation of an autonomous network is coordinated and controlled with one central unit acting as an interface between internal producers/consumers and the rest of the power system. In this study, the power balance problem and system reliability through provision of ancillary services was formulated as an optimization problem for the overall autonomous networks based power system. This paper described the simulation of an optimal autonomous network dispatching in day ahead markets, based on predicted spot prices for real power, and two ancillary services. It was concluded that large changes occur in a power systems structure and operation, most of them adding to the uncertainty and complexity of the system. The introduced concept of an autonomous power network-based power system was shown to be a realistic and consistent approach to formulate and operate a market-based dispatch of both power and ancillary services. 9 refs., 4 figs

  11. Dynamics-based centrality for directed networks.

    Science.gov (United States)

    Masuda, Naoki; Kori, Hiroshi

    2010-11-01

    Determining the relative importance of nodes in directed networks is important in, for example, ranking websites, publications, and sports teams, and for understanding signal flows in systems biology. A prevailing centrality measure in this respect is the PageRank. In this work, we focus on another class of centrality derived from the Laplacian of the network. We extend the Laplacian-based centrality, which has mainly been applied to strongly connected networks, to the case of general directed networks such that we can quantitatively compare arbitrary nodes. Toward this end, we adopt the idea used in the PageRank to introduce global connectivity between all the pairs of nodes with a certain strength. Numerical simulations are carried out on some networks. We also offer interpretations of the Laplacian-based centrality for general directed networks in terms of various dynamical and structural properties of networks. Importantly, the Laplacian-based centrality defined as the stationary density of the continuous-time random walk with random jumps is shown to be equivalent to the absorption probability of the random walk with sinks at each node but without random jumps. Similarly, the proposed centrality represents the importance of nodes in dynamics on the original network supplied with sinks but not with random jumps.

  12. 3 x 3 free-space optical router based on crossbar network and its control algorithm

    Science.gov (United States)

    Hou, Peipei; Sun, Jianfeng; Yu, Zhou; Lu, Wei; Wang, Lijuan; Liu, Liren

    2015-08-01

    A 3 × 3 free-space optical router, which comprises optical switches and polarizing beam splitter (PBS) and based on crossbar network, is proposed in this paper. A control algorithm for the 3 × 3 free-space optical router is also developed to achieve rapid control without rearrangement. In order to test the performance of the network based on 3 × 3 free-space optical router and that of the algorithm developed for the optical router, experiments are designed. The experiment results show that the interconnection network based on the 3 × 3 free-space optical router has low cross talk, fast connection speed. Under the control of the algorithm developed, a non-block and real free interconnection network is obtained based on the 3 × 3 free-space optical router we proposed.

  13. Design of Low Inductance Switching Power Cell for GaN HEMT Based Inverter

    Energy Technology Data Exchange (ETDEWEB)

    Gurpinar, Emre [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Power Electronics and Electric Machinery Research Group; Iannuzzo, Francesco [Aalborg Univ., Aalborg (Denmark). Dept. of Energy Technology; Yang, Yongheng [Aalborg Univ., Aalborg (Denmark). Dept. of Energy Technology; Castellazzi, Alberto [Univ. of Nottingham (United Kingdom). Power Electronics, Machines and Control (PEMC); Blaabjerg, Frede [Aalborg Univ., Aalborg (Denmark). Dept. of Energy Technology

    2017-11-23

    Here in this paper, an ultra-low inductance power cell is designed for a three-Level Active Neutral Point Clamped (3LANPC) based on 650 V gallium nitride (GaN) HEMT devices. The 3L-ANPC topology with GaN HEMT devices and the selected modulation scheme suitable for wide-bandgap (WBG) devices are presented. The commutation loops, which mainly contribute to voltage overshoots and increase of switching losses, are discussed. The ultra-low inductance power cell design based on a fourlayer Printed Circuit Board (PCB) with the aim to maximize the switching performance of GaN HEMTs is explained. The design of gate drivers for the GaN HEMT devices is presented. Parasitic inductance and resistance of the proposed design are extracted with finite element analysis and discussed. Common mode behaviours based on the SPICE model of the converter are analyzed. Experimental results on the designed 3L-ANPC with the output power of up to 1 kW are presented, which verifies the performance of the proposed design in terms of ultra-low inductance.

  14. Configurable Resistive Switching between Memory and Threshold Characteristics for Protein-Based Devices

    KAUST Repository

    Wang, Hong

    2015-05-01

    The employ of natural biomaterials as the basic building blocks of electronic devices is of growing interest for biocompatible and green electronics. Here, resistive switching (RS) devices based on naturally silk protein with configurable functionality are demonstrated. The RS type of the devices can be effectively and exactly controlled by controlling the compliance current in the set process. Memory RS can be triggered by a higher compliance current, while threshold RS can be triggered by a lower compliance current. Furthermore, two types of memory devices, working in random access and WORM modes, can be achieved with the RS effect. The results suggest that silk protein possesses the potential for sustainable electronics and data storage. In addition, this finding would provide important guidelines for the performance optimization of biomaterials based memory devices and the study of the underlying mechanism behind the RS effect arising from biomaterials. Resistive switching (RS) devices with configurable functionality based on protein are successfully achieved. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Design of Low Inductance Switching Power Cell for GaN HEMT Based Inverter

    International Nuclear Information System (INIS)

    Gurpinar, Emre; Iannuzzo, Francesco; Yang, Yongheng; Castellazzi, Alberto; Blaabjerg, Frede

    2017-01-01

    Here in this paper, an ultra-low inductance power cell is designed for a three-Level Active Neutral Point Clamped (3LANPC) based on 650 V gallium nitride (GaN) HEMT devices. The 3L-ANPC topology with GaN HEMT devices and the selected modulation scheme suitable for wide-bandgap (WBG) devices are presented. The commutation loops, which mainly contribute to voltage overshoots and increase of switching losses, are discussed. The ultra-low inductance power cell design based on a fourlayer Printed Circuit Board (PCB) with the aim to maximize the switching performance of GaN HEMTs is explained. The design of gate drivers for the GaN HEMT devices is presented. Parasitic inductance and resistance of the proposed design are extracted with finite element analysis and discussed. Common mode behaviours based on the SPICE model of the converter are analyzed. Experimental results on the designed 3L-ANPC with the output power of up to 1 kW are presented, which verifies the performance of the proposed design in terms of ultra-low inductance.

  16. Playable One-Switch Video Games for Children with Severe Motor Disabilities Based on GNomon

    Directory of Open Access Journals (Sweden)

    Sebastián Aced López

    2015-12-01

    Full Text Available Being able to play games in early years is very important for the development of children. Even though, children with physical disabilities encounter several obstacles that exclude them from engaging in many popular games. In particular, children with severe motor disabilities that rely on one-switch interfaces for accessing electronic devices find dynamic video games completely unplayable. In this paper we present the development and evaluation of GNomon: a framework, based on the NOMON interaction modality, that enables the creation of dynamic one-switch games for children with severe motor disabilities. The framework was designed following a series of guidelines elicited in close collaboration with a team of speech therapists, physiotherapists and psychologists from one of the Local Health Agencies in Turin, Italy. Likewise, three mini games were developed for testing the playability of GNomon-based games. Finally, we conducted a series of trials with 8 children with severe motor disabilities assisted by the health agency, in which we found that all of them enjoyed playing the GNomon- based mini games and that 7 of them were able to interact and play autonomously.

  17. Future optical communication networks beyond 160 Gbit/s based on OTDM

    Science.gov (United States)

    Prati, Giancarlo; Bogoni, Antonella; Poti, Luca

    2005-01-01

    The virtually unlimited bandwidth of optical fibers has caused a great increase in data transmission speed over the past decade and, hence, stimulated high-demand multimedia services such as distance learning, video-conferencing and peer to peer applications. For this reason data traffic is exceeding telephony traffic, and this trend is driving the convergence of telecommunications and computer communications. In this scenario Internet Protocol (IP) is becoming the dominant protocol for any traffic, shifting the attention of the network designers from a circuit switching approach to a packet switching approach. A role of paramount importance in packet switching networks is played by the router that must implement the functionalities to set up and maintain the inter-nodal communications. The main functionalities a router must implement are routing, forwarding, switching, synchronization, contention resolution, and buffering. Nowadays, opto-electronic conversion is still required at each network node to process the incoming signal before routing that to the right output port. However, when the single channel bit rate increases beyond electronic speed limit, Optical Time Division Multiplexing (OTDM) becomes a forced choice, and all-optical processing must be performed to extract the information from the incoming packet. In this paper enabling techniques for ultra-fast all-optical network will be addressed. First a 160 Gbit/s complete transmission system will be considered. As enabling technique, an overview for all-optical logics will be discussed and experimental results will be presented using a particular reconfigurable NOLM based on Self-Phase-Modulation (SPM) or Cross-Phase-Modulation (XPM). Finally, a rough experiment on label extraction, all-optical switching and packet forwarding is shown.

  18. Burst-Switched Optical Networks Supporting Legacy and Future Service Types

    Directory of Open Access Journals (Sweden)

    Gerald Franzl

    2011-01-01

    Full Text Available Focusing on the principles and the paradigm of OBS an overview addressing expectable performance and application issues is presented. Proposals on OBS were published over a decade and the presented techniques spread into many directions. The paper comprises discussions of several challenges that OBS meets, in order to compile the big picture. The OBS principle is presented unrestricted to individual proposals and trends. Merits are openly discussed, considering basic teletraffic theory and common traffic characterisation. A more generic OBS paradigm than usual is impartially discussed and found capable to overcome shortcomings of recent proposals. In conclusion, an OBS that offers different connection types may support most client demands within a sole optical network layer.

  19. Cloud-based Networked Visual Servo Control

    OpenAIRE

    Wu, Haiyan; Lu, Lei; Chen, Chih-Chung; Hirche, Sandra; Kühnlenz, Kolja

    2013-01-01

    The performance of vision-based control systems, in particular of highly dynamic vision-based motion control systems, is often limited by the low sampling rate of the visual feedback caused by the long image processing time. In order to overcome this problem, the networked visual servo control, which integrates networked computational resources for cloud image processing, is considered in this article. The main contributions of this article are i) a real-time transport protocol for transmitti...

  20. MicroRNA-Mediated Positive Feedback Loop and Optimized Bistable Switch in a Cancer Network Involving miR-17-92

    Science.gov (United States)

    Li, Yichen; Li, Yumin; Zhang, Hui; Chen, Yong

    2011-01-01

    MicroRNAs (miRNAs) are small, noncoding RNAs that play an important role in many key biological processes, including development, cell differentiation, the cell cycle and apoptosis, as central post-transcriptional regulators of gene expression. Recent studies have shown that miRNAs can act as oncogenes and tumor suppressors depending on the context. The present work focuses on the physiological significance of miRNAs and their role in regulating the switching behavior. We illustrate an abstract model of the Myc/E2F/miR-17-92 network presented by Aguda et al. (2008), which is composed of coupling between the E2F/Myc positive feedback loops and the E2F/Myc/miR-17-92 negative feedback loop. By systematically analyzing the network in close association with plausible experimental parameters, we show that, in the presence of miRNAs, the system bistability emerges from the system, with a bistable switch and a one-way switch presented by Aguda et al. instead of a single one-way switch. Moreover, the miRNAs can optimize the switching process. The model produces a diverse array of response-signal behaviors in response to various potential regulating scenarios. The model predicts that this transition exists, one from cell death or the cancerous phenotype directly to cell quiescence, due to the existence of miRNAs. It was also found that the network involving miR-17-92 exhibits high noise sensitivity due to a positive feedback loop and also maintains resistance to noise from a negative feedback loop. PMID:22022595