WorldWideScience

Sample records for local computer networks

  1. Personal computer local networks report

    CERN Document Server

    1991-01-01

    Please note this is a Short Discount publication. Since the first microcomputer local networks of the late 1970's and early 80's, personal computer LANs have expanded in popularity, especially since the introduction of IBMs first PC in 1981. The late 1980s has seen a maturing in the industry with only a few vendors maintaining a large share of the market. This report is intended to give the reader a thorough understanding of the technology used to build these systems ... from cable to chips ... to ... protocols to servers. The report also fully defines PC LANs and the marketplace, with in-

  2. An Experiment in Computer Conferencing Using a Local Area Network.

    Science.gov (United States)

    Baird, Patricia M.; Borer, Beatrice

    1987-01-01

    Describes various computer conferencing systems and discusses their effectiveness in terms of user acceptance and reactions to the technology. The methodology and findings of an experiment in which graduate students conducted a computer conference using a local area network and produced an electronic journal of the conference proceedings are…

  3. LaRC local area networks to support distributed computing

    Science.gov (United States)

    Riddle, E. P.

    1984-01-01

    The Langley Research Center's (LaRC) Local Area Network (LAN) effort is discussed. LaRC initiated the development of a LAN to support a growing distributed computing environment at the Center. The purpose of the network is to provide an improved capability (over inteactive and RJE terminal access) for sharing multivendor computer resources. Specifically, the network will provide a data highway for the transfer of files between mainframe computers, minicomputers, work stations, and personal computers. An important influence on the overall network design was the vital need of LaRC researchers to efficiently utilize the large CDC mainframe computers in the central scientific computing facility. Although there was a steady migration from a centralized to a distributed computing environment at LaRC in recent years, the work load on the central resources increased. Major emphasis in the network design was on communication with the central resources within the distributed environment. The network to be implemented will allow researchers to utilize the central resources, distributed minicomputers, work stations, and personal computers to obtain the proper level of computing power to efficiently perform their jobs.

  4. Using a Local Area Network to Teach Computer Revision Skills.

    Science.gov (United States)

    Thompson, Diane P.

    1989-01-01

    Describes the use of a local area network and video switching equipment in teaching revision skills on computer. Explains that reading stories from texts, rewriting them from differing character viewpoints, and editing them as a group exposed students to a variety of writing problems and stimulated various revision strategies. (SG)

  5. A Wireless Sensor Network with Soft Computing Localization Techniques for Track Cycling Applications

    OpenAIRE

    2016-01-01

    In this paper, we propose two soft computing localization techniques for wireless sensor networks (WSNs). The two techniques, Neural Fuzzy Inference System (ANFIS) and Artificial Neural Network (ANN), focus on a range-based localization method which relies on the measurement of the received signal strength indicator (RSSI) from the three ZigBee anchor nodes distributed throughout the track cycling field. The soft computing techniques aim to estimate the distance between bicycles moving on the...

  6. Computationally efficient locally-recurrent neural networks for online signal processing

    CERN Document Server

    Hussain, A; Shim, I

    1999-01-01

    A general class of computationally efficient locally recurrent networks (CERN) is described for real-time adaptive signal processing. The structure of the CERN is based on linear-in-the- parameters single-hidden-layered feedforward neural networks such as the radial basis function (RBF) network, the Volterra neural network (VNN) and the functionally expanded neural network (FENN), adapted to employ local output feedback. The corresponding learning algorithms are derived and key structural and computational complexity comparisons are made between the CERN and conventional recurrent neural networks. Two case studies are performed involving the real- time adaptive nonlinear prediction of real-world chaotic, highly non- stationary laser time series and an actual speech signal, which show that a recurrent FENN based adaptive CERN predictor can significantly outperform the corresponding feedforward FENN and conventionally employed linear adaptive filtering models. (13 refs).

  7. Requirements analysis and design for implementation of a satellite link for a local area computer network

    OpenAIRE

    Lorentzen, Richard B.

    1991-01-01

    Approved for public release; distribution is unlimited The purpose of this thesis is to provide naval computer students with a basic knowledge on Very Small Aperture Terminal (VSAT) satellite technology and to define the hardware and software requirements at the interface between a VSAT and a Local Area Network (LAN). By restricting a computer network to terrestrial links, a vast amount of knowledge is not accessed because either the terrestrial links can't access the information or the...

  8. Implementation of Locally Weighted Projection Regression Network for Concurrency Control In Computer Aided Design

    Directory of Open Access Journals (Sweden)

    A.Muthukumaravel

    2011-08-01

    Full Text Available This paper presents implementation of locally weighted projection regression (LWPR network method for concurrency control while developing dial of a fork using Autodesk inventor 2008. The LWPR learns the objects and the type of transactions to be done based on which node in the output layer of the network exceeds a threshold value. Learning stops once all the objects are exposed to LWPR. During testing performance, metrics are analyzed. We have attempted to use LWPR for storing lock information when multi users are working on computer Aided Design (CAD. The memory requirements of the proposed method are minimal in processing locks during transaction.

  9. Computing the Local Field Potential (LFP from Integrate-and-Fire Network Models.

    Directory of Open Access Journals (Sweden)

    Alberto Mazzoni

    2015-12-01

    Full Text Available Leaky integrate-and-fire (LIF network models are commonly used to study how the spiking dynamics of neural networks changes with stimuli, tasks or dynamic network states. However, neurophysiological studies in vivo often rather measure the mass activity of neuronal microcircuits with the local field potential (LFP. Given that LFPs are generated by spatially separated currents across the neuronal membrane, they cannot be computed directly from quantities defined in models of point-like LIF neurons. Here, we explore the best approximation for predicting the LFP based on standard output from point-neuron LIF networks. To search for this best "LFP proxy", we compared LFP predictions from candidate proxies based on LIF network output (e.g, firing rates, membrane potentials, synaptic currents with "ground-truth" LFP obtained when the LIF network synaptic input currents were injected into an analogous three-dimensional (3D network model of multi-compartmental neurons with realistic morphology, spatial distributions of somata and synapses. We found that a specific fixed linear combination of the LIF synaptic currents provided an accurate LFP proxy, accounting for most of the variance of the LFP time course observed in the 3D network for all recording locations. This proxy performed well over a broad set of conditions, including substantial variations of the neuronal morphologies. Our results provide a simple formula for estimating the time course of the LFP from LIF network simulations in cases where a single pyramidal population dominates the LFP generation, and thereby facilitate quantitative comparison between computational models and experimental LFP recordings in vivo.

  10. Computing the Local Field Potential (LFP) from Integrate-and-Fire Network Models.

    Science.gov (United States)

    Mazzoni, Alberto; Lindén, Henrik; Cuntz, Hermann; Lansner, Anders; Panzeri, Stefano; Einevoll, Gaute T

    2015-12-01

    Leaky integrate-and-fire (LIF) network models are commonly used to study how the spiking dynamics of neural networks changes with stimuli, tasks or dynamic network states. However, neurophysiological studies in vivo often rather measure the mass activity of neuronal microcircuits with the local field potential (LFP). Given that LFPs are generated by spatially separated currents across the neuronal membrane, they cannot be computed directly from quantities defined in models of point-like LIF neurons. Here, we explore the best approximation for predicting the LFP based on standard output from point-neuron LIF networks. To search for this best "LFP proxy", we compared LFP predictions from candidate proxies based on LIF network output (e.g, firing rates, membrane potentials, synaptic currents) with "ground-truth" LFP obtained when the LIF network synaptic input currents were injected into an analogous three-dimensional (3D) network model of multi-compartmental neurons with realistic morphology, spatial distributions of somata and synapses. We found that a specific fixed linear combination of the LIF synaptic currents provided an accurate LFP proxy, accounting for most of the variance of the LFP time course observed in the 3D network for all recording locations. This proxy performed well over a broad set of conditions, including substantial variations of the neuronal morphologies. Our results provide a simple formula for estimating the time course of the LFP from LIF network simulations in cases where a single pyramidal population dominates the LFP generation, and thereby facilitate quantitative comparison between computational models and experimental LFP recordings in vivo.

  11. Initialization and Restart in Stochastic Local Search: Computing a Most Probable Explanation in Bayesian Networks

    Science.gov (United States)

    Mengshoel, Ole J.; Wilkins, David C.; Roth, Dan

    2010-01-01

    For hard computational problems, stochastic local search has proven to be a competitive approach to finding optimal or approximately optimal problem solutions. Two key research questions for stochastic local search algorithms are: Which algorithms are effective for initialization? When should the search process be restarted? In the present work we investigate these research questions in the context of approximate computation of most probable explanations (MPEs) in Bayesian networks (BNs). We introduce a novel approach, based on the Viterbi algorithm, to explanation initialization in BNs. While the Viterbi algorithm works on sequences and trees, our approach works on BNs with arbitrary topologies. We also give a novel formalization of stochastic local search, with focus on initialization and restart, using probability theory and mixture models. Experimentally, we apply our methods to the problem of MPE computation, using a stochastic local search algorithm known as Stochastic Greedy Search. By carefully optimizing both initialization and restart, we reduce the MPE search time for application BNs by several orders of magnitude compared to using uniform at random initialization without restart. On several BNs from applications, the performance of Stochastic Greedy Search is competitive with clique tree clustering, a state-of-the-art exact algorithm used for MPE computation in BNs.

  12. Basics of Computer Networking

    CERN Document Server

    Robertazzi, Thomas

    2012-01-01

    Springer Brief Basics of Computer Networking provides a non-mathematical introduction to the world of networks. This book covers both technology for wired and wireless networks. Coverage includes transmission media, local area networks, wide area networks, and network security. Written in a very accessible style for the interested layman by the author of a widely used textbook with many years of experience explaining concepts to the beginner.

  13. A Wireless Sensor Network with Soft Computing Localization Techniques for Track Cycling Applications

    Directory of Open Access Journals (Sweden)

    Sadik Kamel Gharghan

    2016-08-01

    Full Text Available In this paper, we propose two soft computing localization techniques for wireless sensor networks (WSNs. The two techniques, Neural Fuzzy Inference System (ANFIS and Artificial Neural Network (ANN, focus on a range-based localization method which relies on the measurement of the received signal strength indicator (RSSI from the three ZigBee anchor nodes distributed throughout the track cycling field. The soft computing techniques aim to estimate the distance between bicycles moving on the cycle track for outdoor and indoor velodromes. In the first approach the ANFIS was considered, whereas in the second approach the ANN was hybridized individually with three optimization algorithms, namely Particle Swarm Optimization (PSO, Gravitational Search Algorithm (GSA, and Backtracking Search Algorithm (BSA. The results revealed that the hybrid GSA-ANN outperforms the other methods adopted in this paper in terms of accuracy localization and distance estimation accuracy. The hybrid GSA-ANN achieves a mean absolute distance estimation error of 0.02 m and 0.2 m for outdoor and indoor velodromes, respectively.

  14. A Wireless Sensor Network with Soft Computing Localization Techniques for Track Cycling Applications.

    Science.gov (United States)

    Gharghan, Sadik Kamel; Nordin, Rosdiadee; Ismail, Mahamod

    2016-08-06

    In this paper, we propose two soft computing localization techniques for wireless sensor networks (WSNs). The two techniques, Neural Fuzzy Inference System (ANFIS) and Artificial Neural Network (ANN), focus on a range-based localization method which relies on the measurement of the received signal strength indicator (RSSI) from the three ZigBee anchor nodes distributed throughout the track cycling field. The soft computing techniques aim to estimate the distance between bicycles moving on the cycle track for outdoor and indoor velodromes. In the first approach the ANFIS was considered, whereas in the second approach the ANN was hybridized individually with three optimization algorithms, namely Particle Swarm Optimization (PSO), Gravitational Search Algorithm (GSA), and Backtracking Search Algorithm (BSA). The results revealed that the hybrid GSA-ANN outperforms the other methods adopted in this paper in terms of accuracy localization and distance estimation accuracy. The hybrid GSA-ANN achieves a mean absolute distance estimation error of 0.02 m and 0.2 m for outdoor and indoor velodromes, respectively.

  15. Portfolios in Stochastic Local Search: Efficiently Computing Most Probable Explanations in Bayesian Networks

    Science.gov (United States)

    Mengshoel, Ole J.; Roth, Dan; Wilkins, David C.

    2001-01-01

    Portfolio methods support the combination of different algorithms and heuristics, including stochastic local search (SLS) heuristics, and have been identified as a promising approach to solve computationally hard problems. While successful in experiments, theoretical foundations and analytical results for portfolio-based SLS heuristics are less developed. This article aims to improve the understanding of the role of portfolios of heuristics in SLS. We emphasize the problem of computing most probable explanations (MPEs) in Bayesian networks (BNs). Algorithmically, we discuss a portfolio-based SLS algorithm for MPE computation, Stochastic Greedy Search (SGS). SGS supports the integration of different initialization operators (or initialization heuristics) and different search operators (greedy and noisy heuristics), thereby enabling new analytical and experimental results. Analytically, we introduce a novel Markov chain model tailored to portfolio-based SLS algorithms including SGS, thereby enabling us to analytically form expected hitting time results that explain empirical run time results. For a specific BN, we show the benefit of using a homogenous initialization portfolio. To further illustrate the portfolio approach, we consider novel additive search heuristics for handling determinism in the form of zero entries in conditional probability tables in BNs. Our additive approach adds rather than multiplies probabilities when computing the utility of an explanation. We motivate the additive measure by studying the dramatic impact of zero entries in conditional probability tables on the number of zero-probability explanations, which again complicates the search process. We consider the relationship between MAXSAT and MPE, and show that additive utility (or gain) is a generalization, to the probabilistic setting, of MAXSAT utility (or gain) used in the celebrated GSAT and WalkSAT algorithms and their descendants. Utilizing our Markov chain framework, we show that

  16. IMPACTS OF APPLICATION USAGE AND LOCAL HARDWARE ON THE THROUGHPUT OF COMPUTER NETWORKS WITH DESKTOP VIRTUALIZATION

    Directory of Open Access Journals (Sweden)

    Vitor Chaves De Oliveira

    2013-01-01

    Full Text Available Currently, virtualization solutions are employed in the vast majority of organizations around the world. The reasons for this are the benefits gained by the approach, focusing on increases in security, availability and data integrity. These privileges are also present in a new technique, which emerges from this same concept and is called desktop virtualization. This method, compelled by these advantages, has grown considerably and is likely to be implemented on more than three-quarters of organizations before 2014. As it is a technique based on physical client server architecture, it conducts all its actions on a local computer and responds to user interaction, through clients that are physically elsewhere. This means that the technique depends on the communication network which makes the interaction possible. Therefore, the importance of the network is increased and it is important to study its behavior compared to a traditional desktop solution, that is, a local solution. This article demonstrates the impact related to a Quality of Service (QoS parameter, throughput, which suffered great alterations depending on the implemented computational environment. Concomitantly, other results are expressed concerning the Quality of Experience (QoE decay with a thin client and a significant benefit of virtualization on the QoS, when remote access is required.

  17. computer networks

    Directory of Open Access Journals (Sweden)

    N. U. Ahmed

    2002-01-01

    Full Text Available In this paper, we construct a new dynamic model for the Token Bucket (TB algorithm used in computer networks and use systems approach for its analysis. This model is then augmented by adding a dynamic model for a multiplexor at an access node where the TB exercises a policing function. In the model, traffic policing, multiplexing and network utilization are formally defined. Based on the model, we study such issues as (quality of service QoS, traffic sizing and network dimensioning. Also we propose an algorithm using feedback control to improve QoS and network utilization. Applying MPEG video traces as the input traffic to the model, we verify the usefulness and effectiveness of our model.

  18. Computer-communication networks

    CERN Document Server

    Meditch, James S

    1983-01-01

    Computer- Communication Networks presents a collection of articles the focus of which is on the field of modeling, analysis, design, and performance optimization. It discusses the problem of modeling the performance of local area networks under file transfer. It addresses the design of multi-hop, mobile-user radio networks. Some of the topics covered in the book are the distributed packet switching queuing network design, some investigations on communication switching techniques in computer networks and the minimum hop flow assignment and routing subject to an average message delay constraint

  19. Computing the Local Field Potential (LFP) from Integrate-and-Fire Network Models

    DEFF Research Database (Denmark)

    Mazzoni, Alberto; Linden, Henrik; Cuntz, Hermann

    2015-01-01

    Leaky integrate-and-fire (LIF) network models are commonly used to study how the spiking dynamics of neural networks changes with stimuli, tasks or dynamic network states. However, neurophysiological studies in vivo often rather measure the mass activity of neuronal microcircuits with the local...... point-neuron LIF networks. To search for this best “LFP proxy”, we compared LFP predictions from candidate proxies based on LIF network output (e.g, firing rates, membrane potentials, synaptic currents) with “ground-truth” LFP obtained when the LIF network synaptic input currents were injected...... into an analogous three-dimensional (3D) network model of multi-compartmental neurons with realistic morphology, spatial distributions of somata and synapses. We found that a specific fixed linear combination of the LIF synaptic currents provided an accurate LFP proxy, accounting for most of the variance of the LFP...

  20. Computer networks forensics

    Directory of Open Access Journals (Sweden)

    Ratomir Đ. Đokić

    2013-02-01

    Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 Digital forensics is a set of scientific methods and procedures for collection, analysis and presentation of evidence that can be found on the computers, servers, computer networks, databases, mobile devices, as well as all other devices on which can store (save data. Digital forensics, computer networks is an examination of digital evidence that can be found on servers and user devices, which are exchanged internal or external communication through local or public networks. Also there is a need for identifying sites and modes of origin messages, establish user identification, and detection types of manipulation by logging in to your account. This paper presents the basic elements of computer networks, software used to communicate and describe the methods of collecting digital evidence and their analysis.

  1. Local Social Networks

    DEFF Research Database (Denmark)

    Sapuppo, Antonio; Sørensen, Lene Tolstrup

    2011-01-01

    Online social networks have become essential for many users in their daily communication. Through a combination of the online social networks with opportunistic networks, a new concept arises: Local Social Networks. The target of local social networks is to promote social networking benefits...... in physical environment in order to leverage personal affinities in the users' surroundings. The purpose of this paper is to present and discuss the concept of local social networks as a new social communication system. Particularly, the preliminary architecture and the prototype of local social networks...

  2. Design of a Local Computer Network for the Air Force Institute of Technology Digital Engineering Laboratory.

    Science.gov (United States)

    1981-03-01

    the contention channel protocol. Aproach The development of computer networks has not reached a stage where there is a set development approach to be...used to ref ine the data f lows and processes in the higher level diagrams to sufficient detail. Thus, this method of partitioning allowed the large...structured design techniques proposed by Yourdon and Constantine. Two principal methods were used to translate the structured specification into

  3. Computing network-based features from intracranial EEG time series data: Application to seizure focus localization.

    Science.gov (United States)

    Hao, Stephanie; Subramanian, Sandya; Jordan, Austin; Santaniello, Sabato; Yaffe, Robert; Jouny, Christophe C; Bergey, Gregory K; Anderson, William S; Sarma, Sridevi V

    2014-01-01

    The surgical resection of the epileptogenic zone (EZ) is the only effective treatment for many drug-resistant epilepsy (DRE) patients, but the pre-surgical identification of the EZ is challenging. This study investigates whether the EZ exhibits a computationally identifiable signature during seizures. In particular, we compute statistics of the brain network from intracranial EEG (iEEG) recordings and track the evolution of network connectivity before, during, and after seizures. We define each node in the network as an electrode and weight each edge connecting a pair of nodes by the gamma band cross power of the corresponding iEEG signals. The eigenvector centrality (EVC) of each node is tracked over two seizures per patient and the electrodes are ranked according to the corresponding EVC value. We hypothesize that electrodes covering the EZ have a signature EVC rank evolution during seizure that differs from electrodes outside the EZ. We tested this hypothesis on multi-channel iEEG recordings from 2 DRE patients who had successful surgery (i.e., seizures were under control with or without medications) and 1 patient who had unsuccessful surgery. In the successful cases, we assumed that the resected region contained the EZ and found that the EVC rank evolution of the electrodes within the resected region had a distinct "arc" signature, i.e., the EZ ranks first rose together shortly after seizure onset and then fell later during seizure.

  4. Topological quantum computing with a very noisy network and local error rates approaching one percent.

    Science.gov (United States)

    Nickerson, Naomi H; Li, Ying; Benjamin, Simon C

    2013-01-01

    A scalable quantum computer could be built by networking together many simple processor cells, thus avoiding the need to create a single complex structure. The difficulty is that realistic quantum links are very error prone. A solution is for cells to repeatedly communicate with each other and so purify any imperfections; however prior studies suggest that the cells themselves must then have prohibitively low internal error rates. Here we describe a method by which even error-prone cells can perform purification: groups of cells generate shared resource states, which then enable stabilization of topologically encoded data. Given a realistically noisy network (≥10% error rate) we find that our protocol can succeed provided that intra-cell error rates for initialisation, state manipulation and measurement are below 0.82%. This level of fidelity is already achievable in several laboratory systems.

  5. Local Area Networks: Part I.

    Science.gov (United States)

    Dessy, Raymond E.

    1982-01-01

    Local area networks are common communication conduits allowing various terminals, computers, discs, printers, and other electronic devices to intercommunicate over short distances. Discusses the vocabulary of such networks including RS-232C point-to-point and IEEE-488 multidrop protocols; error detection; message packets; multiplexing; star, ring,…

  6. Introduction to computer networking

    CERN Document Server

    Robertazzi, Thomas G

    2017-01-01

    This book gives a broad look at both fundamental networking technology and new areas that support it and use it. It is a concise introduction to the most prominent, recent technological topics in computer networking. Topics include network technology such as wired and wireless networks, enabling technologies such as data centers, software defined networking, cloud and grid computing and applications such as networks on chips, space networking and network security. The accessible writing style and non-mathematical treatment makes this a useful book for the student, network and communications engineer, computer scientist and IT professional. • Features a concise, accessible treatment of computer networking, focusing on new technological topics; • Provides non-mathematical introduction to networks in their most common forms today;< • Includes new developments in switching, optical networks, WiFi, Bluetooth, LTE, 5G, and quantum cryptography.

  7. Fast Local Computation Algorithms

    CERN Document Server

    Rubinfeld, Ronitt; Vardi, Shai; Xie, Ning

    2011-01-01

    For input $x$, let $F(x)$ denote the set of outputs that are the "legal" answers for a computational problem $F$. Suppose $x$ and members of $F(x)$ are so large that there is not time to read them in their entirety. We propose a model of {\\em local computation algorithms} which for a given input $x$, support queries by a user to values of specified locations $y_i$ in a legal output $y \\in F(x)$. When more than one legal output $y$ exists for a given $x$, the local computation algorithm should output in a way that is consistent with at least one such $y$. Local computation algorithms are intended to distill the common features of several concepts that have appeared in various algorithmic subfields, including local distributed computation, local algorithms, locally decodable codes, and local reconstruction. We develop a technique, based on known constructions of small sample spaces of $k$-wise independent random variables and Beck's analysis in his algorithmic approach to the Lov{\\'{a}}sz Local Lemma, which und...

  8. Complex networks and computing

    Institute of Scientific and Technical Information of China (English)

    Shuigeng ZHOU; Zhongzhi ZHANG

    2009-01-01

    @@ Nowadays complex networks are pervasive in various areas of science and technology. Popular examples of complex networks include the Internet, social networks of collaboration, citations and co-authoring, as well as biological networks such as gene and protein interactions and others. Complex networks research spans across mathematics, computer science, engineering, biology and the social sciences. Even in computer science area, increasing problems are either found to be related to complex networks or studied from the perspective of complex networks, such as searching on Web and P2P networks, routing in sensor networks, language processing, software engineering etc. The interaction and mergence of complex networks and computing is inspiring new chances and challenges in computer science.

  9. Local Area Networks.

    Science.gov (United States)

    Marks, Kenneth E.; Nielsen, Steven

    1991-01-01

    Discusses cabling that is needed in local area networks (LANs). Types of cables that may be selected are described, including twisted pair, coaxial cables (or ethernet), and fiber optics; network topologies, the manner in which the cables are laid out, are considered; and cable installation issues are discussed. (LRW)

  10. Computer network defense system

    Science.gov (United States)

    Urias, Vincent; Stout, William M. S.; Loverro, Caleb

    2017-08-22

    A method and apparatus for protecting virtual machines. A computer system creates a copy of a group of the virtual machines in an operating network in a deception network to form a group of cloned virtual machines in the deception network when the group of the virtual machines is accessed by an adversary. The computer system creates an emulation of components from the operating network in the deception network. The components are accessible by the group of the cloned virtual machines as if the group of the cloned virtual machines was in the operating network. The computer system moves network connections for the group of the virtual machines in the operating network used by the adversary from the group of the virtual machines in the operating network to the group of the cloned virtual machines, enabling protecting the group of the virtual machines from actions performed by the adversary.

  11. Local Area Networks in the School Setting.

    Science.gov (United States)

    Bluhm, Harry P.

    1986-01-01

    Defines local area networks (LANs); describes basic components and configurations of LANs; and discusses LANs benefits (reduced costs, better management of computer resources, enhanced communications) and pitfalls (hidden costs, time delays, network maintenance, lack of standardization, network security breaches, lack of network compatible…

  12. Local area networks

    CERN Document Server

    Zafiropoulo, P

    1982-01-01

    Pitro Zafiropulo is a- staff member at the IBM Research Laboratories at Zurich. He joined IBM in 1968 and has worked on protocol validation, synthesis, integrated networks, network reliability, PABX's and speech recognition. Local Area Networks are intended to provide improved communication capabilities such as high data throughput rates, low error rates and ease of connection among terminal stations and comuters. These new types of networks operate within a limited geographical range like an establishment, campus or building and are owned by a single organization. The presentation introduces these networks and the main techniques are described. It then proceeds to evaluate the main switching techniques as they apply to LAN ring and bus configurations. The preferred technique of token-ring distributed switching is identified. The contents of Mr. Zafiropoulo's talk was somewhat similar to the paper of Mr. Kummerle, which is therefore included in these Proceedings.

  13. Mobile networks and computing

    CERN Document Server

    Rajasekaran, Sanguthevar; Hsu, D Frank

    2000-01-01

    Advances in the technologies of networking, wireless communications, and miniaturization of computers have lead to rapid development in mobile communication infrastructure and have engendered a new paradigm of computing. Users carrying portable devices can now move freely about while remaining connected to the network. This "portability" allows for access to information from anywhere and at any time. The flexibility has resulted in new levels of complexity not encountered previously in software and protocol design for wired networking. New challenges in designing software systems for mobile networks include location and mobility management, channel allocation, power conservation, and more. In this book, renowned researchers in the field address these aspects of mobile networking.

  14. Hyperswitch Communication Network Computer

    Science.gov (United States)

    Peterson, John C.; Chow, Edward T.; Priel, Moshe; Upchurch, Edwin T.

    1993-01-01

    Hyperswitch Communications Network (HCN) computer is prototype multiple-processor computer being developed. Incorporates improved version of hyperswitch communication network described in "Hyperswitch Network For Hypercube Computer" (NPO-16905). Designed to support high-level software and expansion of itself. HCN computer is message-passing, multiple-instruction/multiple-data computer offering significant advantages over older single-processor and bus-based multiple-processor computers, with respect to price/performance ratio, reliability, availability, and manufacturing. Design of HCN operating-system software provides flexible computing environment accommodating both parallel and distributed processing. Also achieves balance among following competing factors; performance in processing and communications, ease of use, and tolerance of (and recovery from) faults.

  15. 计算机局域网技术发展及维护研究%Analysis of Technology Development and Maintenance of Computer Local Area Network

    Institute of Scientific and Technical Information of China (English)

    王锡智

    2013-01-01

      In recent years, computer local area network technology has made an important development, which the wireless LAN network technology to get rid of the burdensome project of laying the cable to enhance the efficiency of the local area network construction and maintenance work efficiency. With the development of local area network technology, the maintenance work becomes more complex and detail, the focus of this article is the analysis to proceed from the development of local area network technology, to further explore the local area network maintenance.%  近些年来计算机局域网技术取得了重要的发展,其中无线局域网更是让网络技术摆脱了铺设电缆的繁冗工程,提升了局域网建设的效率和维护工作的效率。而随着局域网技术的发展,相应的维护工作也变得更加复杂和细致,本文的重点就是从局域网技术的发展分析着手,进一步探究局域网的维护工作。

  16. Computers, Networks and Work.

    Science.gov (United States)

    Sproull, Lee; Kiesler, Sara

    1991-01-01

    Discussed are how computer networks can affect the nature of work and the relationships between managers and employees. The differences between face-to-face exchanges and electronic interactions are described. (KR)

  17. Delayed Commutation in Quantum Computer Networks

    Science.gov (United States)

    García-Escartín, Juan Carlos; Chamorro-Posada, Pedro

    2006-09-01

    In the same way that classical computer networks connect and enhance the capabilities of classical computers, quantum networks can combine the advantages of quantum information and communication. We propose a nonclassical network element, a delayed commutation switch, that can solve the problem of switching time in packet switching networks. With the help of some local ancillary qubits and superdense codes, we can route a qubit packet after part of it has left the network node.

  18. Delayed commutation in quantum computer networks

    CERN Document Server

    Garcia-Escartin, J C; Chamorro-Posada, Pedro; Garcia-Escartin, Juan Carlos

    2005-01-01

    In the same way that classical computer networks connect and enhance the capabilities of classical computers, quantum networks can combine the advantages of quantum information and communications. We propose a non-classical network element, a delayed commutation switch, that can solve the problem of switching time in packet switching networks. With the help of some local ancillary qubits and superdense codes we can route the information after part of it has left the network node.

  19. Local Area Networks: Part II.

    Science.gov (United States)

    Dessy, Raymond E., Ed.

    1982-01-01

    Discusses five approaches used by industry/colleges to provide local area network (LAN) capabilities in the analytical laboratory: (1) mixed baseband bus network coupled to a star net; (2) broadband bus network; (3) ring network; (4) star network coupled to broadband net; and (5) simple multiprocessor center. Part I (September issue) focused on…

  20. Computer network programming

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, J.Y. [California Polytechnic State Univ., San Luis Obispo, CA (United States)

    1996-12-31

    The programs running on a computer network can be divided into two parts, the Network Operating System and the user applications. Any high level language translator, such as C, JAVA, BASIC, FORTRAN, or COBOL, runs under NOS as a programming tool to produce network application programs or software. Each application program while running on the network provides the human user with network application services, such as remote data base search, retrieval, etc. The Network Operating System should provide a simple and elegant system interface to all the network application programs. This programming interface may request the Transport layer services on behalf of a network application program. The primary goals are to achieve programming convenience, and to avoid complexity. In a 5-layer network model, the system interface is comprised of a group of system calls which are collectively known as the session layer with its own Session Protocol Data Units. This is a position paper discussing the basic system primitives which reside between a network application program and the Transport layer, and a programming example of using such primitives.

  1. Inference of Gene Regulatory Network Based on Local Bayesian Networks.

    Science.gov (United States)

    Liu, Fei; Zhang, Shao-Wu; Guo, Wei-Feng; Wei, Ze-Gang; Chen, Luonan

    2016-08-01

    The inference of gene regulatory networks (GRNs) from expression data can mine the direct regulations among genes and gain deep insights into biological processes at a network level. During past decades, numerous computational approaches have been introduced for inferring the GRNs. However, many of them still suffer from various problems, e.g., Bayesian network (BN) methods cannot handle large-scale networks due to their high computational complexity, while information theory-based methods cannot identify the directions of regulatory interactions and also suffer from false positive/negative problems. To overcome the limitations, in this work we present a novel algorithm, namely local Bayesian network (LBN), to infer GRNs from gene expression data by using the network decomposition strategy and false-positive edge elimination scheme. Specifically, LBN algorithm first uses conditional mutual information (CMI) to construct an initial network or GRN, which is decomposed into a number of local networks or GRNs. Then, BN method is employed to generate a series of local BNs by selecting the k-nearest neighbors of each gene as its candidate regulatory genes, which significantly reduces the exponential search space from all possible GRN structures. Integrating these local BNs forms a tentative network or GRN by performing CMI, which reduces redundant regulations in the GRN and thus alleviates the false positive problem. The final network or GRN can be obtained by iteratively performing CMI and local BN on the tentative network. In the iterative process, the false or redundant regulations are gradually removed. When tested on the benchmark GRN datasets from DREAM challenge as well as the SOS DNA repair network in E.coli, our results suggest that LBN outperforms other state-of-the-art methods (ARACNE, GENIE3 and NARROMI) significantly, with more accurate and robust performance. In particular, the decomposition strategy with local Bayesian networks not only effectively reduce

  2. Local Area Networks (The Printout).

    Science.gov (United States)

    Aron, Helen; Balajthy, Ernest

    1989-01-01

    Describes the Local Area Network (LAN), a project in which students used LAN-based word processing and electronic mail software as the center of a writing process approach. Discusses the advantages and disadvantages of networking. (MM)

  3. Enlightenment on Computer Network Reliability From Transportation Network Reliability

    OpenAIRE

    Hu Wenjun; Zhou Xizhao

    2011-01-01

    Referring to transportation network reliability problem, five new computer network reliability definitions are proposed and discussed. They are computer network connectivity reliability, computer network time reliability, computer network capacity reliability, computer network behavior reliability and computer network potential reliability. Finally strategies are suggested to enhance network reliability.

  4. Computer Networks and Globalization

    Directory of Open Access Journals (Sweden)

    J. Magliaro

    2007-07-01

    Full Text Available Communication and information computer networks connect the world in ways that make globalization more natural and inequity more subtle. As educators, we look at these phenomena holistically analyzing them from the realist’s view, thus exploring tensions, (in equity and (injustice, and from the idealist’s view, thus embracing connectivity, convergence and development of a collective consciousness. In an increasingly market- driven world we find examples of openness and human generosity that are based on networks, specifically the Internet. After addressing open movements in publishing, software industry and education, we describe the possibility of a dialectic equilibrium between globalization and indigenousness in view of ecologically designed future smart networks

  5. Local Checkability in Dynamic Networks

    DEFF Research Database (Denmark)

    Förster, Klaus-Tycho; Richter, Oliver; Seidel, Jochen

    2017-01-01

    In this work we study local checkability of network properties considering inconsistency throughout the verification process. We use disappearing and appearing edges to model inconsistency and prover-verifier-pairs (PVPs) for verification. We say that a network property N is locally checkable und...

  6. Localized attack on clustering networks

    CERN Document Server

    Dong, Gaogao; Du, Ruijin; Shao, Shuai; Stanley, H Eugene; Shlomo, Havlin

    2016-01-01

    Clustering network is one of which complex network attracting plenty of scholars to discuss and study the structures and cascading process. We primarily analyzed the effect of clustering coefficient to other various of the single clustering network under localized attack. These network models including double clustering network and star-like NON with clustering and random regular (RR) NON of ER networks with clustering are made up of at least two networks among which exist interdependent relation among whose degree of dependence is measured by coupling strength. We show both analytically and numerically, how the coupling strength and clustering coefficient effect the percolation threshold, size of giant component, critical coupling point where the behavior of phase transition changes from second order to first order with the increase of coupling strength between the networks. Last, we study the two types of clustering network: one type is same with double clustering network in which each subnetwork satisfies ...

  7. Computer Networks and Networking: A Primer.

    Science.gov (United States)

    Collins, Mauri P.

    1993-01-01

    Provides a basic introduction to computer networks and networking terminology. Topics addressed include modems; the Internet; TCP/IP (Transmission Control Protocol/Internet Protocol); transmission lines; Internet Protocol numbers; network traffic; Fidonet; file transfer protocol (FTP); TELNET; electronic mail; discussion groups; LISTSERV; USENET;…

  8. Inference of Gene Regulatory Network Based on Local Bayesian Networks.

    Directory of Open Access Journals (Sweden)

    Fei Liu

    2016-08-01

    Full Text Available The inference of gene regulatory networks (GRNs from expression data can mine the direct regulations among genes and gain deep insights into biological processes at a network level. During past decades, numerous computational approaches have been introduced for inferring the GRNs. However, many of them still suffer from various problems, e.g., Bayesian network (BN methods cannot handle large-scale networks due to their high computational complexity, while information theory-based methods cannot identify the directions of regulatory interactions and also suffer from false positive/negative problems. To overcome the limitations, in this work we present a novel algorithm, namely local Bayesian network (LBN, to infer GRNs from gene expression data by using the network decomposition strategy and false-positive edge elimination scheme. Specifically, LBN algorithm first uses conditional mutual information (CMI to construct an initial network or GRN, which is decomposed into a number of local networks or GRNs. Then, BN method is employed to generate a series of local BNs by selecting the k-nearest neighbors of each gene as its candidate regulatory genes, which significantly reduces the exponential search space from all possible GRN structures. Integrating these local BNs forms a tentative network or GRN by performing CMI, which reduces redundant regulations in the GRN and thus alleviates the false positive problem. The final network or GRN can be obtained by iteratively performing CMI and local BN on the tentative network. In the iterative process, the false or redundant regulations are gradually removed. When tested on the benchmark GRN datasets from DREAM challenge as well as the SOS DNA repair network in E.coli, our results suggest that LBN outperforms other state-of-the-art methods (ARACNE, GENIE3 and NARROMI significantly, with more accurate and robust performance. In particular, the decomposition strategy with local Bayesian networks not only

  9. Hybrid centralized pre-computing/local distributed optimization of shared disjoint-backup path approach to GMPLS optical mesh network intelligent restoration

    Science.gov (United States)

    Gong, Qian; Xu, Rong; Lin, Jintong

    2004-04-01

    Wavelength Division Multiplexed (WDM) networks that route optical connections using intelligent optical cross-connects (OXCs) is firmly established as the core constituent of next generation networks. Rapid failure recovery is fundamental to building reliable transport networks. Mesh restoration promises cost effective failure recovery compared with legacy ring networks, and is now seeing large-scale deployment. Many carriers are migrating away from SONET ring restoration for their core transport networks and replacing it with mesh restoration through "intelligent" O-E-O cross-connects (XC). The mesh restoration is typically provided via two fiber-disjoint paths: a service path and a restoration path. this scheme can restore any single link failure or node failure. And by used shared mesh restoration, although every service route is assigned a restoration route, no dedicated capacity needs to be reserved for the restoration route, resulting in capacity savings. The restoration approach we propose is Centralized Pre-computing, Local Distributed Optimization, and Shared Disjoint-backup Path. This approach combines the merits of centralized and distributed solutions. It avoids the scalability issues of centralized solutions by using a distributed control plane for disjoint service path computation and restoration path provisioning. Moreover, if the service routes of two demands are disjoint, no single failure will affect both demands simultaneously. This means that the restoration routes of these two demands can share link capacities, because these two routes will not be activated at the same time. So we can say, this restoration capacity sharing approach achieves low restoration capacity and fast restoration speed, while requiring few control plane changes.

  10. Computing networks from cluster to cloud computing

    CERN Document Server

    Vicat-Blanc, Pascale; Guillier, Romaric; Soudan, Sebastien

    2013-01-01

    "Computing Networks" explores the core of the new distributed computing infrastructures we are using today:  the networking systems of clusters, grids and clouds. It helps network designers and distributed-application developers and users to better understand the technologies, specificities, constraints and benefits of these different infrastructures' communication systems. Cloud Computing will give the possibility for millions of users to process data anytime, anywhere, while being eco-friendly. In order to deliver this emerging traffic in a timely, cost-efficient, energy-efficient, and

  11. INFORMATION SECURITY IN COMPUTER NETWORKS

    OpenAIRE

    Мехед, Д. Б.

    2016-01-01

    The article deals with computer networks, types of construction, the analysis of the advantages and disadvantages of different types of networks. The basic types of information transmission, highlighted their advantages and disadvantages, losing information and methods of protection.

  12. Functional Localization of Genetic Network Programming

    Science.gov (United States)

    Eto, Shinji; Hirasawa, Kotaro; Hu, Jinglu

    According to the knowledge of brain science, it is suggested that there exists cerebral functional localization, which means that a specific part of the cerebrum is activated depending on various kinds of information human receives. The aim of this paper is to build an artificial model to realize functional localization based on Genetic Network Programming (GNP), a new evolutionary computation method recently developed. GNP has a directed graph structure suitable for realizing functional localization. We studied the basic characteristics of the proposed system by making GNP work in a functionally localized way.

  13. Computational network design from functional specifications

    KAUST Repository

    Peng, Chi Han

    2016-07-11

    Connectivity and layout of underlying networks largely determine agent behavior and usage in many environments. For example, transportation networks determine the flow of traffic in a neighborhood, whereas building floorplans determine the flow of people in a workspace. Designing such networks from scratch is challenging as even local network changes can have large global effects. We investigate how to computationally create networks starting from only high-level functional specifications. Such specifications can be in the form of network density, travel time versus network length, traffic type, destination location, etc. We propose an integer programming-based approach that guarantees that the resultant networks are valid by fulfilling all the specified hard constraints and that they score favorably in terms of the objective function. We evaluate our algorithm in two different design settings, street layout and floorplans to demonstrate that diverse networks can emerge purely from high-level functional specifications.

  14. Queuing theory models for computer networks

    Science.gov (United States)

    Galant, David C.

    1989-01-01

    A set of simple queuing theory models which can model the average response of a network of computers to a given traffic load has been implemented using a spreadsheet. The impact of variations in traffic patterns and intensities, channel capacities, and message protocols can be assessed using them because of the lack of fine detail in the network traffic rates, traffic patterns, and the hardware used to implement the networks. A sample use of the models applied to a realistic problem is included in appendix A. Appendix B provides a glossary of terms used in this paper. This Ames Research Center computer communication network is an evolving network of local area networks (LANs) connected via gateways and high-speed backbone communication channels. Intelligent planning of expansion and improvement requires understanding the behavior of the individual LANs as well as the collection of networks as a whole.

  15. Eradicating Computer Viruses on Networks

    CERN Document Server

    Huang, Jinyu

    2012-01-01

    Spread of computer viruses can be modeled as the SIS (susceptible-infected-susceptible) epidemic propagation. We show that in order to ensure the random immunization or the targeted immunization effectively prevent computer viruses propagation on homogeneous networks, we should install antivirus programs in every computer node and frequently update those programs. This may produce large work and cost to install and update antivirus programs. Then we propose a new policy called "network monitors" to tackle this problem. In this policy, we only install and update antivirus programs for small number of computer nodes, namely the "network monitors". Further, the "network monitors" can monitor their neighboring nodes' behavior. This mechanism incur relative small cost to install and update antivirus programs.We also indicate that the policy of the "network monitors" is efficient to protect the network's safety. Numerical simulations confirm our analysis.

  16. Advances in Navy pharmacy information technology: accessing Micromedex via the Composite Healthcare Computer System and local area networks.

    Science.gov (United States)

    Koerner, S D; Becker, F

    1999-07-01

    The pharmacy profession has long used technology to more effectively bring health care to the patient. Navy pharmacy has embraced technology advances in its daily operations, from computers to dispensing robots. Evolving from the traditional role of compounding and dispensing specialists, pharmacists are establishing themselves as vital team members in direct patient care: on the ward, in ambulatory clinics, in specialty clinics, and in other specialty patient care programs (e.g., smoking cessation). An important part of the evolution is the timely access to the most up-to-date information available. Micromedex, Inc. (Denver, Colorado), has developed a number of computer CD-ROM-based full-text pharmacy, toxicology, emergency medicine, and patient education products. Micromedex is a recognized leader with regard to total pharmaceutical information availability. This article discusses the implementation of Micromedex products within the established Composite Healthcare Computer System and the subsequent use by and effect on the international Navy pharmacy community.

  17. Computer Networks A Systems Approach

    CERN Document Server

    Peterson, Larry L

    2011-01-01

    This best-selling and classic book teaches you the key principles of computer networks with examples drawn from the real world of network and protocol design. Using the Internet as the primary example, the authors explain various protocols and networking technologies. Their systems-oriented approach encourages you to think about how individual network components fit into a larger, complex system of interactions. Whatever your perspective, whether it be that of an application developer, network administrator, or a designer of network equipment or protocols, you will come away with a "big pictur

  18. Understanding and designing computer networks

    CERN Document Server

    King, Graham

    1995-01-01

    Understanding and Designing Computer Networks considers the ubiquitous nature of data networks, with particular reference to internetworking and the efficient management of all aspects of networked integrated data systems. In addition it looks at the next phase of networking developments; efficiency and security are covered in the sections dealing with data compression and data encryption; and future examples of network operations, such as network parallelism, are introduced.A comprehensive case study is used throughout the text to apply and illustrate new techniques and concepts as th

  19. Local Network Wideband Interconnection Alternatives.

    Science.gov (United States)

    1984-01-01

    greater than 1.5 Mbps and two standard televison channels. 1.1 SCOPE Interconnection of local area networks within the continental United States is...may influence : a. Media selection, b. Interface design, c. The use of the 1.5 Mbps data transmission capacity, and d. Adherence to the full-motion video

  20. Computer network environment planning and analysis

    Science.gov (United States)

    Dalphin, John F.

    1989-01-01

    The GSFC Computer Network Environment provides a broadband RF cable between campus buildings and ethernet spines in buildings for the interlinking of Local Area Networks (LANs). This system provides terminal and computer linkage among host and user systems thereby providing E-mail services, file exchange capability, and certain distributed computing opportunities. The Environment is designed to be transparent and supports multiple protocols. Networking at Goddard has a short history and has been under coordinated control of a Network Steering Committee for slightly more than two years; network growth has been rapid with more than 1500 nodes currently addressed and greater expansion expected. A new RF cable system with a different topology is being installed during summer 1989; consideration of a fiber optics system for the future will begin soon. Summmer study was directed toward Network Steering Committee operation and planning plus consideration of Center Network Environment analysis and modeling. Biweekly Steering Committee meetings were attended to learn the background of the network and the concerns of those managing it. Suggestions for historical data gathering have been made to support future planning and modeling. Data Systems Dynamic Simulator, a simulation package developed at NASA and maintained at GSFC was studied as a possible modeling tool for the network environment. A modeling concept based on a hierarchical model was hypothesized for further development. Such a model would allow input of newly updated parameters and would provide an estimation of the behavior of the network.

  1. A quantum computer network

    CERN Document Server

    Kesidis, George

    2009-01-01

    Wong's diffusion network is a stochastic, zero-input Hopfield network with a Gibbs stationary distribution over a bounded, connected continuum. Previously, logarithmic thermal annealing was demonstrated for the diffusion network and digital versions of it were studied and applied to imaging. Recently, "quantum" annealed Markov chains have garnered significant attention because of their improved performance over "pure" thermal annealing. In this note, a joint quantum and thermal version of Wong's diffusion network is described and its convergence properties are studied. Different choices for "auxiliary" functions are discussed, including those of the kinetic type previously associated with quantum annealing.

  2. Local Area Networks and the Learning Lab of the Future.

    Science.gov (United States)

    Ebersole, Dennis C.

    1987-01-01

    Considers educational applications of local area computer networks and discusses industry standards for design established by the International Standards Organization (ISO) and Institute of Electrical and Electronic Engineers (IEEE). A futuristic view of a learning laboratory using a local area network is presented. (Author/LRW)

  3. Computing with Spiking Neuron Networks

    NARCIS (Netherlands)

    Paugam-Moisy, H.; Bohte, S.M.; Rozenberg, G.; Baeck, T.H.W.; Kok, J.N.

    2012-01-01

    Abstract Spiking Neuron Networks (SNNs) are often referred to as the 3rd gener- ation of neural networks. Highly inspired from natural computing in the brain and recent advances in neurosciences, they derive their strength and interest from an ac- curate modeling of synaptic interactions between neu

  4. Spontaneous ad hoc mobile cloud computing network.

    Science.gov (United States)

    Lacuesta, Raquel; Lloret, Jaime; Sendra, Sandra; Peñalver, Lourdes

    2014-01-01

    Cloud computing helps users and companies to share computing resources instead of having local servers or personal devices to handle the applications. Smart devices are becoming one of the main information processing devices. Their computing features are reaching levels that let them create a mobile cloud computing network. But sometimes they are not able to create it and collaborate actively in the cloud because it is difficult for them to build easily a spontaneous network and configure its parameters. For this reason, in this paper, we are going to present the design and deployment of a spontaneous ad hoc mobile cloud computing network. In order to perform it, we have developed a trusted algorithm that is able to manage the activity of the nodes when they join and leave the network. The paper shows the network procedures and classes that have been designed. Our simulation results using Castalia show that our proposal presents a good efficiency and network performance even by using high number of nodes.

  5. Analysis of computer networks

    CERN Document Server

    Gebali, Fayez

    2015-01-01

    This textbook presents the mathematical theory and techniques necessary for analyzing and modeling high-performance global networks, such as the Internet. The three main building blocks of high-performance networks are links, switching equipment connecting the links together, and software employed at the end nodes and intermediate switches. This book provides the basic techniques for modeling and analyzing these last two components. Topics covered include, but are not limited to: Markov chains and queuing analysis, traffic modeling, interconnection networks and switch architectures and buffering strategies.   ·         Provides techniques for modeling and analysis of network software and switching equipment; ·         Discusses design options used to build efficient switching equipment; ·         Includes many worked examples of the application of discrete-time Markov chains to communication systems; ·         Covers the mathematical theory and techniques necessary for ana...

  6. Computational Social Network Analysis

    CERN Document Server

    Hassanien, Aboul-Ella

    2010-01-01

    Presents insight into the social behaviour of animals (including the study of animal tracks and learning by members of the same species). This book provides web-based evidence of social interaction, perceptual learning, information granulation and the behaviour of humans and affinities between web-based social networks

  7. Wealth networks with local redistribution

    Science.gov (United States)

    Kim, Sunggon; Kim, Gwang Il; Lee, Geymin

    2008-08-01

    We propose a growing network model of the distribution of wealth in a society with local redistribution. Individuals, represented by nodes in the model, provide goods and services to one of their neighbors and they simultaneously produce wealth using goods and services received from their neighbors. A proportion of the wealth produced by a node is redistributed to its neighbors as a reward for the received goods and services. Nodes have different ability to produce wealth. We analyze the interaction between the wealth accumulation process and the structure of the network, and analyze also how the interaction is affected by the redistribution of wealth. It is investigated how rich nodes attract the individuals entering the network in this model. Under a reasonable distribution of ability, simulation result shows that the distribution of degree, i.e. number of neighbors of a node, is scale-free, and that the wealth distribution for the middle class is a log-normal distribution, while for the richest it shows a power-law behavior. We also show that the local redistribution of wealth has a significant effect on the distribution of both degree and wealth.

  8. Computer Network Security- The Challenges of Securing a Computer Network

    Science.gov (United States)

    Scotti, Vincent, Jr.

    2011-01-01

    This article is intended to give the reader an overall perspective on what it takes to design, implement, enforce and secure a computer network in the federal and corporate world to insure the confidentiality, integrity and availability of information. While we will be giving you an overview of network design and security, this article will concentrate on the technology and human factors of securing a network and the challenges faced by those doing so. It will cover the large number of policies and the limits of technology and physical efforts to enforce such policies.

  9. Local Undergraduate Colleges and Universities of Computer Network Experiment Curriculum Implementation Scheme%地方本科院校的计算机网络实验课程实施方案探讨

    Institute of Scientific and Technical Information of China (English)

    郭赛球; 胡奇光

    2014-01-01

    Computer network experiment course in colleges and universities, this paper put forward a kind of computer network experiment of suitable for local universities and colleges of undergraduate course course of the implementation of the scheme.%该文针对高等院校的计算机网络实验课程,提出一种适合于地方本科院校的计算机网络实验课程的实施方案。

  10. On computer vision in wireless sensor networks.

    Energy Technology Data Exchange (ETDEWEB)

    Berry, Nina M.; Ko, Teresa H.

    2004-09-01

    Wireless sensor networks allow detailed sensing of otherwise unknown and inaccessible environments. While it would be beneficial to include cameras in a wireless sensor network because images are so rich in information, the power cost of transmitting an image across the wireless network can dramatically shorten the lifespan of the sensor nodes. This paper describe a new paradigm for the incorporation of imaging into wireless networks. Rather than focusing on transmitting images across the network, we show how an image can be processed locally for key features using simple detectors. Contrasted with traditional event detection systems that trigger an image capture, this enables a new class of sensors which uses a low power imaging sensor to detect a variety of visual cues. Sharing these features among relevant nodes cues specific actions to better provide information about the environment. We report on various existing techniques developed for traditional computer vision research which can aid in this work.

  11. Adaptive localization and tracking of objects in a sensor network

    OpenAIRE

    2014-01-01

    [ANGLÈS] Wireless Sensor Networks (WSNs) are used to monitor physical or environmental conditions, and to pass their data through the network to a central location. These networks have applications in diverse areas including environmental, health monitoring, home automation or military. The devices that form the network have limited resources, such as power and computational capacity.\\par This thesis focus on the localization and tracking problem, presenting a method that can be used with obj...

  12. Collective network for computer structures

    Science.gov (United States)

    Blumrich, Matthias A; Coteus, Paul W; Chen, Dong; Gara, Alan; Giampapa, Mark E; Heidelberger, Philip; Hoenicke, Dirk; Takken, Todd E; Steinmacher-Burow, Burkhard D; Vranas, Pavlos M

    2014-01-07

    A system and method for enabling high-speed, low-latency global collective communications among interconnected processing nodes. The global collective network optimally enables collective reduction operations to be performed during parallel algorithm operations executing in a computer structure having a plurality of the interconnected processing nodes. Router devices are included that interconnect the nodes of the network via links to facilitate performance of low-latency global processing operations at nodes of the virtual network. The global collective network may be configured to provide global barrier and interrupt functionality in asynchronous or synchronized manner. When implemented in a massively-parallel supercomputing structure, the global collective network is physically and logically partitionable according to the needs of a processing algorithm.

  13. Collective network for computer structures

    Energy Technology Data Exchange (ETDEWEB)

    Blumrich, Matthias A. (Ridgefield, CT); Coteus, Paul W. (Yorktown Heights, NY); Chen, Dong (Croton On Hudson, NY); Gara, Alan (Mount Kisco, NY); Giampapa, Mark E. (Irvington, NY); Heidelberger, Philip (Cortlandt Manor, NY); Hoenicke, Dirk (Ossining, NY); Takken, Todd E. (Brewster, NY); Steinmacher-Burow, Burkhard D. (Wernau, DE); Vranas, Pavlos M. (Bedford Hills, NY)

    2011-08-16

    A system and method for enabling high-speed, low-latency global collective communications among interconnected processing nodes. The global collective network optimally enables collective reduction operations to be performed during parallel algorithm operations executing in a computer structure having a plurality of the interconnected processing nodes. Router devices ate included that interconnect the nodes of the network via links to facilitate performance of low-latency global processing operations at nodes of the virtual network and class structures. The global collective network may be configured to provide global barrier and interrupt functionality in asynchronous or synchronized manner. When implemented in a massively-parallel supercomputing structure, the global collective network is physically and logically partitionable according to needs of a processing algorithm.

  14. Disease Localization in Multilayer Networks

    Science.gov (United States)

    de Arruda, Guilherme Ferraz; Cozzo, Emanuele; Peixoto, Tiago P.; Rodrigues, Francisco A.; Moreno, Yamir

    2017-01-01

    We present a continuous formulation of epidemic spreading on multilayer networks using a tensorial representation, extending the models of monoplex networks to this context. We derive analytical expressions for the epidemic threshold of the susceptible-infected-susceptible (SIS) and susceptible-infected-recovered dynamics, as well as upper and lower bounds for the disease prevalence in the steady state for the SIS scenario. Using the quasistationary state method, we numerically show the existence of disease localization and the emergence of two or more susceptibility peaks, which are characterized analytically and numerically through the inverse participation ratio. At variance with what is observed in single-layer networks, we show that disease localization takes place on the layers and not on the nodes of a given layer. Furthermore, when mapping the critical dynamics to an eigenvalue problem, we observe a characteristic transition in the eigenvalue spectra of the supra-contact tensor as a function of the ratio of two spreading rates: If the rate at which the disease spreads within a layer is comparable to the spreading rate across layers, the individual spectra of each layer merge with the coupling between layers. Finally, we report on an interesting phenomenon, the barrier effect; i.e., for a three-layer configuration, when the layer with the lowest eigenvalue is located at the center of the line, it can effectively act as a barrier to the disease. The formalism introduced here provides a unifying mathematical approach to disease contagion in multiplex systems, opening new possibilities for the study of spreading processes.

  15. Dynamic Localization Schemes in Malicious Sensor Networks

    Directory of Open Access Journals (Sweden)

    Kaiqi Xiong

    2009-10-01

    Full Text Available Wireless sensor networks (WSN have recently shown many potential military and civilian applications, especially those used in hostile environments where malicious adversaries can be present. The accuracy of location information is critical for such applications. It is impractical to have a GPS device on each sensor in WSN due to costs. Most of the existing location discovery schemes can only be used in the trusted environment. Recent research has addressed security issues in sensor network localization, but to the best of our knowledge, none have completely solved the secure localization problem. In this paper, we propose novel schemes for secure dynamic localization in sensor networks. These proposed schemes can tolerate up to 50% of beacon nodes being malicious, and they have linear computation time with respect to the number of reference nodes. Our security analysis has showed that our schemes are applicable and resilient to attacks from adversaries. We have further conducted simulations to analyze and compare the performance of these schemes, and to indicate when each should be used. The efficiencies of each method shows why we needed to propose multiple methods.

  16. Computing on Anonymous Quantum Network

    CERN Document Server

    Kobayashi, Hirotada; Tani, Seiichiro

    2010-01-01

    This paper considers distributed computing on an anonymous quantum network, a network in which no party has a unique identifier and quantum communication and computation are available. It is proved that the leader election problem can exactly (i.e., without error in bounded time) be solved with at most the same complexity up to a constant factor as that of exactly computing symmetric functions (without intermediate measurements for a distributed and superposed input), if the number of parties is given to every party. A corollary of this result is a more efficient quantum leader election algorithm than existing ones: the new quantum algorithm runs in O(n) rounds with bit complexity O(mn^2), on an anonymous quantum network with n parties and m communication links. Another corollary is the first quantum algorithm that exactly computes any computable Boolean function with round complexity O(n) and with smaller bit complexity than that of existing classical algorithms in the worst case over all (computable) Boolea...

  17. The Local Area Network and the Cooperative Learning Principle.

    Science.gov (United States)

    Sloan, Fred A.; Koohang, Alex A.

    1991-01-01

    Discussion of the advantages of local area networks (LANs) focuses on their use for successful cooperative learning. Individual and group assessment of success are discussed, effects on academic and affective achievement are considered, and computer-assisted instruction (CAI) programs to use with networking are suggested. (19 references) (LRW)

  18. A Geac Local Area Network for the Bobst Library.

    Science.gov (United States)

    Persky, Gail; And Others

    1984-01-01

    Provides detailed description of New York University's (NYU) Bobst Library Local Area Network (LAN), which was designed and implemented by Geac Computers International technical personnel and NYU library systems staff. Definitions of terminology, why the library installed a LAN, planning, network installation, and the LAN configuration and…

  19. Local Area Network: What Can a Library Do with It?

    Science.gov (United States)

    Dermody, Melinda Bako

    With the ever growing interest that libraries have in the Internet, the potentials of other computer resources may be overlooked or under-utilized. One such resource is the campus local area network (LAN). For libraries, a campus LAN presents possibilities ranging from simple library promotion to networked databases. The Internet provides…

  20. Wireless Local Area Network (WLAN) Vulnerability Assessment and Security

    Science.gov (United States)

    2005-09-01

    vulnerability assessment capability within the Marine Corps. 15. NUMBER OF PAGES 177 14. SUBJECT TERMS Wireless Local Area Network (WLAN), WiFi ... WiFi Protected Access xviii THIS PAGE INTENTIONALLY LEFT BLANK xix...intelligence officers in how to hack into U.S. computers2. Government networks, proprietary commercial information, and scientific research are all

  1. Effect of Maintenance on Computer Network Reliability

    Directory of Open Access Journals (Sweden)

    Rima Oudjedi Damerdji

    2014-08-01

    Full Text Available At the time of the new information technologies, computer networks are inescapable in any large organization, where they are organized so as to form powerful internal means of communication. In a context of dependability, the reliability parameter proves to be fundamental to evaluate the performances of such systems. In this paper, we study the reliability evaluation of a real computer network, through three reliability models. The computer network considered (set of PCs and server interconnected is localized in a company established in the west of Algeria and dedicated to the production of ammonia and fertilizers. The result permits to compare between the three models to determine the most appropriate reliability model to the studied network, and thus, contribute to improving the quality of the network. In order to anticipate system failures as well as improve the reliability and availability of the latter, we must put in place a policy of adequate and effective maintenance based on a new model of the most common competing risks in maintenance, Alert-Delay model. At the end, dependability measures such as MTBF and reliability are calculated to assess the effectiveness of maintenance strategies and thus, validate the alert delay model.

  2. The Educational Importance of Local Area Networks in Secondary Schools.

    Science.gov (United States)

    Shor, Richard

    1989-01-01

    Presents reasons for choosing a connected computer system for student use in secondary schools. The systems approach is discussed; two alternatives are compared, a central computer and a local area network (LAN) of microcomputers; software is described; and two scenarios of LAN use are presented. (four references) (LRW)

  3. Automated Bilingual Circulation System Using PC Local Area Networks.

    Science.gov (United States)

    Iskanderani, A. I.; Anwar, M. A.

    1992-01-01

    Describes a local automated bilingual circulation system using personal computers in a local area network that was developed at King Abdulaziz University (Saudi Arabia) for Arabic and English materials. Topics addressed include the system structure, hardware, major features, storage requirements, and costs. (nine references) (LRW)

  4. Anchored boundary conditions for locally isostatic networks

    Science.gov (United States)

    Theran, Louis; Nixon, Anthony; Ross, Elissa; Sadjadi, Mahdi; Servatius, Brigitte; Thorpe, M. F.

    2015-11-01

    Finite pieces of locally isostatic networks have a large number of floppy modes because of missing constraints at the surface. Here we show that by imposing suitable boundary conditions at the surface the network can be rendered effectively isostatic. We refer to these as anchored boundary conditions. An important example is formed by a two-dimensional network of corner sharing triangles, which is the focus of this paper. Another way of rendering such networks isostatic is by adding an external wire along which all unpinned vertices can slide (sliding boundary conditions). This approach also allows for the incorporation of boundaries associated with internal holes and complex sample geometries, which are illustrated with examples. The recent synthesis of bilayers of vitreous silica has provided impetus for this work. Experimental results from the imaging of finite pieces at the atomic level need such boundary conditions, if the observed structure is to be computer refined so that the interior atoms have the perception of being in an infinite isostatic environment.

  5. Quantum computing in neural networks

    CERN Document Server

    Gralewicz, P

    2004-01-01

    According to the statistical interpretation of quantum theory, quantum computers form a distinguished class of probabilistic machines (PMs) by encoding n qubits in 2n pbits. This raises the possibility of a large-scale quantum computing using PMs, especially with neural networks which have the innate capability for probabilistic information processing. Restricting ourselves to a particular model, we construct and numerically examine the performance of neural circuits implementing universal quantum gates. A discussion on the physiological plausibility of proposed coding scheme is also provided.

  6. Snowmass 2013 Computing Frontier: Networking

    CERN Document Server

    Bell, Gregory

    2013-01-01

    Computing has become a major component of all particle physics experiments and in many areas of theoretical particle physics. Progress in HEP experiment and theory will require significantly more computing, software development, storage, and networking, with different projects stretching future capabilities in different ways. However, there are many common needs among different areas in HEP, so more community planning is advised to increase efficiency. Careful and continuing review of the topics we studied, i.e., user needs and capabilities of current and future technology, is needed.

  7. Performing a local reduction operation on a parallel computer

    Science.gov (United States)

    Blocksome, Michael A.; Faraj, Daniel A.

    2012-12-11

    A parallel computer including compute nodes, each including two reduction processing cores, a network write processing core, and a network read processing core, each processing core assigned an input buffer. Copying, in interleaved chunks by the reduction processing cores, contents of the reduction processing cores' input buffers to an interleaved buffer in shared memory; copying, by one of the reduction processing cores, contents of the network write processing core's input buffer to shared memory; copying, by another of the reduction processing cores, contents of the network read processing core's input buffer to shared memory; and locally reducing in parallel by the reduction processing cores: the contents of the reduction processing core's input buffer; every other interleaved chunk of the interleaved buffer; the copied contents of the network write processing core's input buffer; and the copied contents of the network read processing core's input buffer.

  8. Markov Networks in Evolutionary Computation

    CERN Document Server

    Shakya, Siddhartha

    2012-01-01

    Markov networks and other probabilistic graphical modes have recently received an upsurge in attention from Evolutionary computation community, particularly in the area of Estimation of distribution algorithms (EDAs).  EDAs have arisen as one of the most successful experiences in the application of machine learning methods in optimization, mainly due to their efficiency to solve complex real-world optimization problems and their suitability for theoretical analysis. This book focuses on the different steps involved in the conception, implementation and application of EDAs that use Markov networks, and undirected models in general. It can serve as a general introduction to EDAs but covers also an important current void in the study of these algorithms by explaining the specificities and benefits of modeling optimization problems by means of undirected probabilistic models. All major developments to date in the progressive introduction of Markov networks based EDAs are reviewed in the book. Hot current researc...

  9. MIGRANT AND LOCAL ENTREPRENEURIAL NETWORKS DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    James D. Adam

    2004-01-01

    Full Text Available This study examines factors influencing migrant and local entrepreneurial business networks with particular reference to Provincial development in Indonesia. Factors of influence include market accessibility, capital accessibility, business focus or business specialisation in manufacturing, trades and services as well as economic conditions, degree of tolerance towards migrant and local entrepreneurs, support networks, business experience, educational background, and entrepreneurial personal characteristics and initiatives. The findings have significance for local development by entrepreneurs in this special case where migrant and local entrepreneurs link in networks and in many cases, joint ventures. The outcomes have significance for government in development programs, academic institutions designing training, and for local business organisation.

  10. EEG source localization: a neural network approach.

    Science.gov (United States)

    Sclabassi, R J; Sonmez, M; Sun, M

    2001-07-01

    Functional activity in the brain is associated with the generation of currents and resultant voltages which may be observed on the scalp as the electroencephelogram. The current sources may be modeled as dipoles. The properties of the current dipole sources may be studied by solving either the forward or inverse problems. The forward problem utilizes a volume conductor model for the head, in which the potentials on the conductor surface are computed based on an assumed current dipole at an arbitrary location, orientation, and strength. In the inverse problem, on the other hand, a current dipole, or a group of dipoles, is identified based on the observed EEG. Both the forward and inverse problems are typically solved by numerical procedures, such as a boundary element method and an optimization algorithm. These approaches are highly time-consuming and unsuitable for the rapid evaluation of brain function. In this paper we present a different approach to these problems based on machine learning. We solve both problems using artificial neural networks which are trained off-line using back-propagation techniques to learn the complex source-potential relationships of head volume conduction. Once trained, these networks are able to generalize their knowledge to localize functional activity within the brain in a computationally efficient manner.

  11. CD-ROM and Local Area Networks.

    Science.gov (United States)

    Marks, Kenneth E.; And Others

    1993-01-01

    This special section on local area networks includes three articles: (1) a description of migration at Joyner Library, East Carolina University (North Carolina) to a new network server; (2) a discussion of factors to consider for network planning in school libraries; and (3) a directory of companies supplying cable, hardware, software, and…

  12. Local Area Networks: Reaping the Benefits.

    Science.gov (United States)

    Raymond, Chadwick; Anderson, Charles

    1987-01-01

    Description of the planning and implementation of a microcomputer-based local area network in the Northbrook (Illinois) Public Library highlights: (1) applying for a grant; (2) network design; (3) the bidding process; (4) installation; (5) implementing the network; and (6) problems and cautions. (MES)

  13. Local Area Networks for Information Retrieval.

    Science.gov (United States)

    Kibirige, Harry M.

    This examination of the use of local area networks (LANs) by libraries summarizes the findings of a nationwide survey of 600 libraries and information centers and 200 microcomputer networking system manufacturers and vendors, which was conducted to determine the relevance of currently available networking systems for library and information center…

  14. CD-ROM and Local Area Networks.

    Science.gov (United States)

    Marks, Kenneth E.; And Others

    1993-01-01

    This special section on local area networks includes three articles: (1) a description of migration at Joyner Library, East Carolina University (North Carolina) to a new network server; (2) a discussion of factors to consider for network planning in school libraries; and (3) a directory of companies supplying cable, hardware, software, and…

  15. Attractor dynamics in local neuronal networks

    Directory of Open Access Journals (Sweden)

    Jean-Philippe eThivierge

    2014-03-01

    Full Text Available Patterns of synaptic connectivity in various regions of the brain are characterized by the presence of synaptic motifs, defined as unidirectional and bidirectional synaptic contacts that follow a particular configuration and link together small groups of neurons. Recent computational work proposes that a relay network (two populations communicating via a third, relay population of neurons can generate precise patterns of neural synchronization. Here, we employ two distinct models of neuronal dynamics and show that simulated neural circuits designed in this way are caught in a global attractor of activity that prevents neurons from modulating their response on the basis of incoming stimuli. To circumvent the emergence of a fixed global attractor, we propose a mechanism of selective gain inhibition that promotes flexible responses to external stimuli. We suggest that local neuronal circuits may employ this mechanism to generate precise patterns of neural synchronization whose transient nature delimits the occurrence of a brief stimulus.

  16. Wireless Network Coding with Local Network Views: Coded Layer Scheduling

    CERN Document Server

    Vahid, Alireza; Avestimehr, A Salman; Sabharwal, Ashutosh

    2011-01-01

    One of the fundamental challenges in the design of distributed wireless networks is the large dynamic range of network state. Since continuous tracking of global network state at all nodes is practically impossible, nodes can only acquire limited local views of the whole network to design their transmission strategies. In this paper, we study multi-layer wireless networks and assume that each node has only a limited knowledge, namely 1-local view, where each S-D pair has enough information to perform optimally when other pairs do not interfere, along with connectivity information for rest of the network. We investigate the information-theoretic limits of communication with such limited knowledge at the nodes. We develop a novel transmission strategy, namely Coded Layer Scheduling, that solely relies on 1-local view at the nodes and incorporates three different techniques: (1) per layer interference avoidance, (2) repetition coding to allow overhearing of the interference, and (3) network coding to allow inter...

  17. Distinct types of eigenvector localization in networks

    CERN Document Server

    Pastor-Satorras, Romualdo

    2016-01-01

    The spectral properties of the adjacency matrix provide a trove of information about the structure and function of complex networks. In particular, the largest eigenvalue and its associated principal eigenvector are crucial in the understanding of node's centrality and the unfolding of dynamical processes. Here we show that two distinct types of localization of the principal eigenvector may occur in heterogeneous networks. For synthetic networks with degree distribution $P(q) \\sim q^{-\\gamma}$, localization occurs on the largest hub if $\\gamma>5/2$; for $\\gamma<5/2$ a new type of localization arises on a mesoscopic subgraph associated to the shell with the largest index in the $K$-core decomposition. Similar evidence for the existence of distinct localization modes is found in the analysis of real-world networks. Our results open a new perspective on dynamical processes on networks and on a recently proposed alternative measure of node centrality based on the non-backtracking matrix.

  18. Percolation of localized attack on complex networks

    CERN Document Server

    Shao, Shuai; Stanley, H Eugene; Havlin, Shlomo

    2014-01-01

    The robustness of complex networks against node failure and malicious attack has been of interest for decades, while most of the research has focused on random attack or hub-targeted attack. In many real-world scenarios, however, attacks are neither random nor hub-targeted, but localized, where a group of neighboring nodes in a network are attacked and fail. In this paper we develop a percolation framework to analytically and numerically study the robustness of complex networks against such localized attack. In particular, we investigate this robustness in Erd\\H{o}s-R\\'{e}nyi networks, random-regular networks, and scale-free networks. Our results provide insight into how to better protect networks, enhance cybersecurity, and facilitate the design of more robust infrastructures.

  19. Computational social networks security and privacy

    CERN Document Server

    2012-01-01

    Presents the latest advances in security and privacy issues in computational social networks, and illustrates how both organizations and individuals can be protected from real-world threats Discusses the design and use of a wide range of computational tools and software for social network analysis Provides experience reports, survey articles, and intelligence techniques and theories relating to specific problems in network technology

  20. Local Natural Connectivity in Complex Networks

    Institute of Scientific and Technical Information of China (English)

    SHANG Yi-Lun

    2011-01-01

    @@ In network theory, a complex network represents a system whose evolving structure and dynamic behavior contribute to its robustness.The natural connectivity is recently proposed as a spectral measure to characterize the robustness of complex networks.We decompose the natural connectivity of a network as local natural connectivity of its connected components and quantify their contributions to the network robustness.In addition, we compare the natural connectivity of a network with that of an induced subgraph of it based on interlacing theorems.As an application, we derive an inequality for eigenvalues of ErdSs-Renyi random graphs.%In network theory, a complex network represents a system whose evolving structure and dynamic behavior contribute to its robustness. The natural connectivity is recently proposed as a spectral measure to characterize the robustness of complex networks. We decompose the natural connectivity of a network as local naturai connectivity of its connected components and quantify their contributions to the network robustness. In addition, we compare the naturai connectivity of a network with that of an induced subgraph of it based on interlacing theorems. As an application, we derive an inequality for eigenvalues of Erdos-Renyi random graphs.

  1. Global efficiency of local immunization on complex networks

    CERN Document Server

    Hébert-Dufresne, Laurent; Young, Jean-Gabriel; Dubé, Louis J

    2012-01-01

    Epidemics occur in all shapes and forms: infections propagating in our sparse sexual networks, information spreading through our much denser social interactions, or viruses circulating on the Internet. With the advent of large databases and efficient analysis algorithms, these processes can be better predicted and controlled. In this study, we use different characteristics of network organization to identify the influential spreaders in networks of diverse nature. We propose a local measure of node influence based on the network's community structure which is easily estimated in real systems and frequently outperforms the usual measure of a node's importance. More importantly, through an extensive study spanning 17 empirical networks and 2 epidemic models, we formulate a readily applicable approach which proves efficient even though different networks and different diseases require different strategies.This research is expected to guide efforts regarding public health policies, computer network security and t...

  2. Law of localization in chemical reaction networks

    CERN Document Server

    Okada, Takashi

    2016-01-01

    In living cells, chemical reactions are connected by sharing their products and substrates, and form complex networks, e.g. metabolic pathways. Here we developed a theory to predict the sensitivity, i.e. the responses of concentrations and fluxes to perturbations of enzymes, from network structure alone. Responses turn out to exhibit two characteristic patterns, $localization$ and $hierarchy$. We present a general theorem connecting sensitivity with network topology that explains these characteristic patterns. Our results imply that network topology is an origin of biological robustness. Finally, we suggest a strategy to determine real networks from experimental measurements.

  3. Protecting information on local area networks

    CERN Document Server

    Schweitzer, James A

    1988-01-01

    Protecting Information on Local Area Networks presents the various types of networks and explains why they are being expanded at such a rapid pace. This book considers how management can gain control of the valuable network-services information resources generally available.Organized into three parts encompassing seven chapters, this book begins with an overview of the various networks and their operations. This text then discusses the appropriate management actions to ensure some control over the use of networks and the business information resource. Other chapters consider the management rat

  4. The one-way quantum computer - a non-network model of quantum computation

    CERN Document Server

    Raussendorf, R; Briegel, H J; Raussendorf, Robert; Browne, Daniel E.; Briegel, Hans J.

    2001-01-01

    A one-way quantum computer works by only performing a sequence of one-qubit measurements on a particular entangled multi-qubit state, the cluster state. No non-local operations are required in the process of computation. Any quantum logic network can be simulated on the one-way quantum computer. On the other hand, the network model of quantum computation cannot explain all ways of processing quantum information possible with the one-way quantum computer. In this paper, two examples of the non-network character of the one-way quantum computer are given. First, circuits in the Clifford group can be performed in a single time step. Second, the realisation of a particular circuit --the bit-reversal gate-- on the one-way quantum computer has no network interpretation. (Submitted to J. Mod. Opt, Gdansk ESF QIT conference issue.)

  5. Selecting a Local Area Network for an Academic Environment.

    Science.gov (United States)

    Aman, Mohammed M.; And Others

    1990-01-01

    Describes the process used to select a local area network (LAN) for the University of Wisconsin-Milwaukee School of Library and Information Science. The use of computers at the library school by staff, faculty, and students is described, technical aspects of a LAN are explained, and the future of LANs is discussed. (LRW)

  6. Fast Distributed Computation of Distances in Networks

    CERN Document Server

    Almeida, Paulo Sérgio; Cunha, Alcino

    2011-01-01

    This paper presents a distributed algorithm to simultaneously compute the diameter, radius and node eccentricity in all nodes of a synchronous network. Such topological information may be useful as input to configure other algorithms. Previous approaches have been modular, progressing in sequential phases using building blocks such as BFS tree construction, thus incurring longer executions than strictly required. We present an algorithm that, by timely propagation of available estimations, achieves a faster convergence to the correct values. We show local criteria for detecting convergence in each node. The algorithm avoids the creation of BFS trees and simply manipulates sets of node ids and hop counts. For the worst scenario of variable start times, each node i with eccentricity ecc(i) can compute: the node eccentricity in diam(G)+ecc(i)+2 rounds; the diameter in 2*diam(G)+ecc(i)+2 rounds; and the radius in diam(G)+ecc(i)+2*radius(G) rounds.

  7. Cooperative Localization on Computationally Constrained Devices

    Science.gov (United States)

    2012-03-22

    special hardware, or extra devices to store the database or make computations. Research also deals with specific localization techniques such as using Wi...localization to the smart phone platform, specifically to take advantage of the multiple sensors commonly available. The entire system runs on Android ...localization. The result of the research effort is software written for the Android platform that can improve on a location estimate. By conducting

  8. Network as a computer: ranking paths to find flows

    CERN Document Server

    Pavlovic, Dusko

    2008-01-01

    We explore a simple mathematical model of network computation, based on Markov chains. Similar models apply to a broad range of computational phenomena, arising in networks of computers, as well as in genetic, and neural nets, in social networks, and so on. The main problem of interaction with such spontaneously evolving computational systems is that the data are not uniformly structured. An interesting approach is to try to extract the semantical content of the data from their distribution among the nodes. A concept is then identified by finding the community of nodes that share it. The task of data structuring is thus reduced to the task of finding the network communities, as groups of nodes that together perform some non-local data processing. Towards this goal, we extend the ranking methods from nodes to paths. This allows us to extract some information about the likely flow biases from the available static information about the network.

  9. Local Area Networks and Classroom Anarchy.

    Science.gov (United States)

    Stanley, Ron

    1992-01-01

    Explores the use of local area networks (LAN's) in learning laboratories and how they are improving learning outcomes for certain student populations (e.g., deaf and developmental students). Describes how LAN's alter the instructor's role and how instructors can manage student-driven classrooms. Offers guidance on implementing a network system.…

  10. The university computer network security system

    Institute of Scientific and Technical Information of China (English)

    张丁欣

    2012-01-01

    With the development of the times, advances in technology, computer network technology has been deep into all aspects of people's lives, it plays an increasingly important role, is an important tool for information exchange. Colleges and universities is to cultivate the cradle of new technology and new technology, computer network Yulu nectar to nurture emerging technologies, and so, as institutions of higher learning should pay attention to the construction of computer network security system.

  11. Computer networks ISE a systems approach

    CERN Document Server

    Peterson, Larry L

    2007-01-01

    Computer Networks, 4E is the only introductory computer networking book written by authors who have had first-hand experience with many of the protocols discussed in the book, who have actually designed some of them as well, and who are still actively designing the computer networks today. This newly revised edition continues to provide an enduring, practical understanding of networks and their building blocks through rich, example-based instruction. The authors' focus is on the why of network design, not just the specifications comprising today's systems but how key technologies and p

  12. Program For Local-Area-Network Electronic Mail

    Science.gov (United States)

    Weiner, Michael J.

    1989-01-01

    MailRoom is computer program for local-area network (LAN) electronic mail. Enables users of LAN to exchange electronically notes, letters, reminders, or any sort of communication via their computers. Links all users of LAN into communication circle in which messages created, sent, copied, printed, downloaded, uploaded, and deleted through series of menu-driven screens. Includes feature that enables users to determine whether messages sent have been read by receivers. Written in Microsoft QuickBasic.

  13. Products and Services for Computer Networks.

    Science.gov (United States)

    Negroponte, Nicholas P.

    1991-01-01

    Creative applications of computer networks are discussed. Products and services of the future that come from imaginative applications of both channel and computing capacity are described. The topics of entertainment, transactions, and electronic personal surrogates are included. (KR)

  14. Citizen Involvement in Local Security Networks

    NARCIS (Netherlands)

    Terpstra, J.B.

    2009-01-01

    This paper deals with the involvement of citizens (and local businesspersons) in the prevention and control of crime and disorder. Four models of citizen involvement in local security networks are distinguished. In each of these models the role of citizens concentrates on different functions: (1) p

  15. Localized recovery of complex networks against failure

    Science.gov (United States)

    Shang, Yilun

    2016-07-01

    Resilience of complex networks to failure has been an important issue in network research for decades, and recent studies have begun to focus on the inverse recovery of network functionality through strategically healing missing nodes or edges. However, the effect of network recovery is far from fully understood, and a general theory is still missing. Here we propose and study a general model of localized recovery, where a group of neighboring nodes are restored in an invasive way from a seed node. We develop a theoretical framework to compare the effect of random recovery (RR) and localized recovery (LR) in complex networks including Erdős-Rényi networks, random regular networks, and scale-free networks. We find detailed phase diagrams for the subnetwork of occupied nodes and the “complement network” of failed nodes under RR and LR. By identifying the two competitive forces behind LR, we present an analytical and numerical approach to guide us in choosing the appropriate recovery strategy and provide estimation on its effect by using the degree distribution of the original network as the only input. Our work therefore provides insight for quantitatively understanding recovery process and its implications in infrastructure protection in various complex systems.

  16. Cooperative Localization for Mobile Networks

    DEFF Research Database (Denmark)

    Cakmak, Burak; Urup, Daniel Nygaard; Meyer, Florian;

    2016-01-01

    We propose a hybrid message passing method for distributed cooperative localization and tracking of mobile agents. Belief propagation and mean field message passing are employed for, respectively, the motion-related and measurementrelated part of the factor graph. Using a Gaussian belief approxim...... approximation, only three real values per message passing iteration have to be broadcast to neighboring agents. Despite these very low communication requirements, the estimation accuracy can be comparable to that of particle-based belief propagation....

  17. Adaptive computational resource allocation for sensor networks

    Institute of Scientific and Technical Information of China (English)

    WANG Dian-hong; FEI E; YAN Yu-jie

    2008-01-01

    To efficiently utilize the limited computational resource in real-time sensor networks, this paper focu-ses on the challenge of computational resource allocation in sensor networks and provides a solution with the method of economies. It designs a mieroeconomic system in which the applications distribute their computational resource consumption across sensor networks by virtue of mobile agent. Further, it proposes the market-based computational resource allocation policy named MCRA which satisfies the uniform consumption of computational energy in network and the optimal division of the single computational capacity for multiple tasks. The simula-tion in the scenario of target tracing demonstrates that MCRA realizes an efficient allocation of computational re-sources according to the priority of tasks, achieves the superior allocation performance and equilibrium perform-ance compared to traditional allocation policies, and ultimately prolongs the system lifetime.

  18. Event Localization in Underwater Wireless Sensor Networks using Monitoring Courses

    KAUST Repository

    Debont, Matthew

    2011-11-01

    In this thesis we consider different methods to localize events in a multi-hop wireless sensor network operating underwater using acoustic modems. The network consists of surface gateway nodes and relay nodes. Localization of surface gateways can be achieved through GPS, but we cannot rely on this technology for localizing underwater nodes. Surface Gateway nodes can distribute their locations through the network using the incoming signals by the acoustic modems from the relay nodes. Relay nodes are deployed to remain static but due to water currents, floating, and the untethered nature of the nodes, they often suffer from frequent drifting which can result in a deployed network suffering link failures. In this work, we developed a novel concept of an underwater alarming system, which adapts a cyclic graph model. In the event of link failure, a series of alarm packets are broadcasted in the network. These alarms are then captured through a novel concept of underwater Monitoring Courses (M-Courses), which can also be used to assure network connectivity and identify node faults. M-Courses also allow the network to localize events and identify network issues at a local level before forwarding any results upwards to a Surface Gateway nodes. This reduces the amount of communication overhead needed and allowing for distributed management of nodes in a network which may be constantly moving. We show that the proposed algorithms can reduce the number of send operations needed for an event to be localized in a network. We have found that M-Course routing reduces the number of sends required to report an event to a Surface Gateway by up to 80% in some cases when compared to a naive routing implementation. But this is achieved by increasing the time for an event to reach a Surface Gateway. These effects are both due to the buffering effect of M-Course routing, which allows us to efficiently deal with multiple events in an local area and we find that the performance of M

  19. Computing preimages of Boolean networks

    Science.gov (United States)

    2013-01-01

    In this paper we present an algorithm based on the sum-product algorithm that finds elements in the preimage of a feed-forward Boolean networks given an output of the network. Our probabilistic method runs in linear time with respect to the number of nodes in the network. We evaluate our algorithm for randomly constructed Boolean networks and a regulatory network of Escherichia coli and found that it gives a valid solution in most cases. PMID:24267277

  20. Mobile Agents in Networking and Distributed Computing

    CERN Document Server

    Cao, Jiannong

    2012-01-01

    The book focuses on mobile agents, which are computer programs that can autonomously migrate between network sites. This text introduces the concepts and principles of mobile agents, provides an overview of mobile agent technology, and focuses on applications in networking and distributed computing.

  1. Application of local area networks to accelerator control systems at the Stanford Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Fox, J.D.; Linstadt, E.; Melen, R.

    1983-03-01

    The history and current status of SLAC's SDLC networks for distributed accelerator control systems are discussed. These local area networks have been used for instrumentation and control of the linear accelerator. Network topologies, protocols, physical links, and logical interconnections are discussed for specific applications in distributed data acquisition and control system, computer networks and accelerator operations.

  2. HeNCE: A Heterogeneous Network Computing Environment

    Directory of Open Access Journals (Sweden)

    Adam Beguelin

    1994-01-01

    Full Text Available Network computing seeks to utilize the aggregate resources of many networked computers to solve a single problem. In so doing it is often possible to obtain supercomputer performance from an inexpensive local area network. The drawback is that network computing is complicated and error prone when done by hand, especially if the computers have different operating systems and data formats and are thus heterogeneous. The heterogeneous network computing environment (HeNCE is an integrated graphical environment for creating and running parallel programs over a heterogeneous collection of computers. It is built on a lower level package called parallel virtual machine (PVM. The HeNCE philosophy of parallel programming is to have the programmer graphically specify the parallelism of a computation and to automate, as much as possible, the tasks of writing, compiling, executing, debugging, and tracing the network computation. Key to HeNCE is a graphical language based on directed graphs that describe the parallelism and data dependencies of an application. Nodes in the graphs represent conventional Fortran or C subroutines and the arcs represent data and control flow. This article describes the present state of HeNCE, its capabilities, limitations, and areas of future research.

  3. FFT-local gravimetric geoid computation

    Science.gov (United States)

    Nagy, Dezso; Fury, Rudolf J.

    1989-01-01

    Model computations show that changes of sampling interval introduce only 0.3 cm changes, whereas zero padding provides an improvement of more than 5 cm in the fast Fourier transformation (FFT) generated geoid. For the Global Positioning System (GPS) survey of Franklin County, Ohio, the parameters selected as a result of model computations, allow large reduction in local data requirements while still retaining the cm accuracy when tapering and padding is applied. The results are shown in tables.

  4. Automated classification of computer network attacks

    CSIR Research Space (South Africa)

    Van Heerden, R

    2013-11-01

    Full Text Available In this paper we demonstrate how an automated reasoner, HermiT, is used to classify instances of computer network based attacks in conjunction with a network attack ontology. The ontology describes different types of network attacks through classes...

  5. Local Area Network DI Agnostic Package

    Science.gov (United States)

    Oestereicher, Charles

    1984-08-01

    This paper describes the design of a Local Area Network (LAN) diagnostic package This program will contain "confidence" type test routines, and commands designed to aid in detecting failures and improve the use of the LAN services during normal operations. The approach selected requires installing the same copy of the program in selected bus interface units(bius) and a subset in all the others bius. Those bius containing the full set of options are the controlling nodes; more than one controlling node can run concurrently its own diagnostic program. Messages generated when exercising the different resources and interfaces of the LAN will be stored and/or displayed on appropriate positions. As a minimum the LAN will have one controlling node which will be the location of the LAN's technical control. The diagnostics will provide data to aid in mana-ging the system, accepting or declining requests for connections, allocating additional ports, declaring sectors inoperable, off lining nodes, devices, functions, and reconfiguring the system as necessary. Host computers can optionally have the full blown diagnostic program, which allows them to be a controlling node, or a subset of the diagnostic program with enough capabilities to interface with its host front end biu (hfe). The diagnostics will have its own application protocol and will utilize the ser-vices of the Internet Protocol (IP) to transport messages to their destinations.

  6. Metastable Localization of Diseases in Complex Networks

    CERN Document Server

    Ferreira, R S; Dorogovtsev, S N; Mendes, J F F

    2016-01-01

    We describe the phenomenon of localization in the epidemic SIS model on highly heterogeneous networks in which strongly connected nodes (hubs) play the role of centers of localization. We find that in this model the localized states below the epidemic threshold are metastable. The longevity and scale of the metastable outbreaks do not show a sharp localization transition, instead there is a smooth crossover from localized to delocalized states as we approach the epidemic threshold from below. Analyzing these long-lasting local outbreaks for a regular random graph (Bethe lattice) with a hub, we show how this localization can be detected from the shape of the distribution of the number of infective nodes.

  7. Local dynamics of gap-junction-coupled interneuron networks

    Science.gov (United States)

    Lau, Troy; Gage, Gregory J.; Berke, Joshua D.; Zochowski, Michal

    2010-03-01

    Interneurons coupled by both electrical gap-junctions (GJs) and chemical GABAergic synapses are major components of forebrain networks. However, their contributions to the generation of specific activity patterns, and their overall contributions to network function, remain poorly understood. Here we demonstrate, using computational methods, that the topological properties of interneuron networks can elicit a wide range of activity dynamics, and either prevent or permit local pattern formation. We systematically varied the topology of GJ and inhibitory chemical synapses within simulated networks, by changing connection types from local to random, and changing the total number of connections. As previously observed we found that randomly coupled GJs lead to globally synchronous activity. In contrast, we found that local GJ connectivity may govern the formation of highly spatially heterogeneous activity states. These states are inherently temporally unstable when the input is uniformly random, but can rapidly stabilize when the network detects correlations or asymmetries in the inputs. We show a correspondence between this feature of network activity and experimental observations of transient stabilization of striatal fast-spiking interneurons (FSIs), in electrophysiological recordings from rats performing a simple decision-making task. We suggest that local GJ coupling enables an active search-and-select function of striatal FSIs, which contributes to the overall role of cortical-basal ganglia circuits in decision-making.

  8. The Security of Wireless Local Area Network

    Institute of Scientific and Technical Information of China (English)

    林楠; 李翠霞

    2007-01-01

    The Wireless Local Area Network (WLAN) is a new and developing technology and the security problem is always important in all networks; therefore, the security problems will be discussed in this article. The article firstly introduces the history of development of IEEE 802.11 and provides an overview of the Wireless LAN. The architecture of WLAN will be referred in next. Finally, the further of the wireless LAN will be prospected by this article.

  9. Integrating network awareness in ATLAS distributed computing

    CERN Document Server

    De, K; The ATLAS collaboration; Klimentov, A; Maeno, T; Mckee, S; Nilsson, P; Petrosyan, A; Vukotic, I; Wenaus, T

    2014-01-01

    A crucial contributor to the success of the massively scaled global computing system that delivers the analysis needs of the LHC experiments is the networking infrastructure upon which the system is built. The experiments have been able to exploit excellent high-bandwidth networking in adapting their computing models for the most efficient utilization of resources. New advanced networking technologies now becoming available such as software defined networks hold the potential of further leveraging the network to optimize workflows and dataflows, through proactive control of the network fabric on the part of high level applications such as experiment workload management and data management systems. End to end monitoring of networking and data flow performance further allows applications to adapt based on real time conditions. We will describe efforts underway in ATLAS on integrating network awareness at the application level, particularly in workload management.

  10. Emerging localized food networks in Denmark

    DEFF Research Database (Denmark)

    Kristensen, Niels Heine; Hansen, Mette Weinreich

    2012-01-01

    One of the fastest growing food related social movements are citizen driven food networks. The Danish initiatives emerged in Copenhagen from an open culinary, social, environmental and organic oriented network. The theories and strategies of the original initiative is presented in this paper......, together with an analysis of how this has evolved and expanded. The challenges this rapid expansion puts on the internal network and organisation, and on the local food supplieres - the organic farmers - are elaborated in this paper. Also – from a rural sociology perspective – the interaction...

  11. Emerging localized food networks in Denmark

    DEFF Research Database (Denmark)

    Kristensen, Niels Heine; Hansen, Mette Weinreich

    2012-01-01

    One of the fastest growing food related social movements are citizen driven food networks. The Danish initiatives emerged in Copenhagen from an open culinary, social, environmental and organic oriented network. The theories and strategies of the original initiative is presented in this paper......, together with an analysis of how this has evolved and expanded. The challenges this rapid expansion puts on the internal network and organisation, and on the local food supplieres - the organic farmers - are elaborated in this paper. Also – from a rural sociology perspective – the interaction...

  12. Airlines Network Optimization using Evolutionary Computation

    Science.gov (United States)

    Inoue, Hiroki; Kato, Yasuhiko; Sakagami, Tomoya

    In recent years, various networks have come to exist in our surroundings. Not only the internet and airline routes can be thought of as networks: protein interactions are also networks. An “economic network design problem” can be discussed by assuming that a vertex is an economic player and that a link represents some connection between economic players. In this paper, the Airlines network is taken up as an example of an “economic network design problem”, and the Airlines network which the profit of the entire Airlines industry is maximized is clarified. The Airlines network is modeled based on connections models proposed by Jackson and Wolinsky, and the utility function of the network is defined. In addition, the optimization simulation using the evolutionary computation is shown for a domestic airline in Japan.

  13. Local computation of differents and discriminants

    CERN Document Server

    Nart, Enric

    2012-01-01

    We obtain several results on the computation of different and discriminant ideals of finite extensions of local fields. As an application, we deduce routines to compute the $\\p$-adic valuation of the discriminant $\\dsc(f)$, and the resultant $\\res(f,g)$, for polynomials $f(x),g(x)\\in A[x]$, where $A$ is a Dedekind domain and $\\p$ is a non-zero prime ideal of $A$ with finite residue field. These routines do not require the computation of neither $\\dsc(f)$ nor $\\res(f,g)$; hence, they are useful in cases where this latter computation is inefficient because the polynomials have a large degree or very large coefficients.

  14. On-line learning algorithms for locally recurrent neural networks.

    Science.gov (United States)

    Campolucci, P; Uncini, A; Piazza, F; Rao, B D

    1999-01-01

    This paper focuses on on-line learning procedures for locally recurrent neural networks with emphasis on multilayer perceptron (MLP) with infinite impulse response (IIR) synapses and its variations which include generalized output and activation feedback multilayer networks (MLN's). We propose a new gradient-based procedure called recursive backpropagation (RBP) whose on-line version, causal recursive backpropagation (CRBP), presents some advantages with respect to the other on-line training methods. The new CRBP algorithm includes as particular cases backpropagation (BP), temporal backpropagation (TBP), backpropagation for sequences (BPS), Back-Tsoi algorithm among others, thereby providing a unifying view on gradient calculation techniques for recurrent networks with local feedback. The only learning method that has been proposed for locally recurrent networks with no architectural restriction is the one by Back and Tsoi. The proposed algorithm has better stability and higher speed of convergence with respect to the Back-Tsoi algorithm, which is supported by the theoretical development and confirmed by simulations. The computational complexity of the CRBP is comparable with that of the Back-Tsoi algorithm, e.g., less that a factor of 1.5 for usual architectures and parameter settings. The superior performance of the new algorithm, however, easily justifies this small increase in computational burden. In addition, the general paradigms of truncated BPTT and RTRL are applied to networks with local feedback and compared with the new CRBP method. The simulations show that CRBP exhibits similar performances and the detailed analysis of complexity reveals that CRBP is much simpler and easier to implement, e.g., CRBP is local in space and in time while RTRL is not local in space.

  15. Local Area Network Management: An Unresolved Issue.

    Science.gov (United States)

    Howden, Norman

    1989-01-01

    Discussion of management issues involved with local area networks (LAN) among information organizations focuses on a project at the University of North Texas that was designed to investigate problems associated with LAN. Topics discussed include purchasing decisions for hardware and software, and integration among various groups of users. (Eight…

  16. Wireless Laptops and Local Area Networks.

    Science.gov (United States)

    Tolson, Stephanie Diane

    2001-01-01

    Describes experiences at St. Louis Community College at Florissant Valley (Missouri) with the use of wireless technology and a local area network for library bibliographic instruction. Discusses faculty input and attitudes; technical challenges; and experiences at other community colleges that have found wireless connections more economical than…

  17. Local Area Networks--For Your Library?

    Science.gov (United States)

    Leggott, Mark

    1989-01-01

    Describes a typical configuration for a local area network (LAN), and discusses positive and negative factors to be considered when deciding whether to implement a LAN in a library setting. Situations in which LANS are or are not appropriate are identified, and alternatives to LANs are described. (CLB)

  18. On local optima in learning bayesian networks

    DEFF Research Database (Denmark)

    Dalgaard, Jens; Kocka, Tomas; Pena, Jose

    2003-01-01

    This paper proposes and evaluates the k-greedy equivalence search algorithm (KES) for learning Bayesian networks (BNs) from complete data. The main characteristic of KES is that it allows a trade-off between greediness and randomness, thus exploring different good local optima. When greediness...

  19. Sensor Network Localization with Imprecise Distances

    NARCIS (Netherlands)

    Cao, M.; Morse, A.S.; Anderson, B.D.O.

    2006-01-01

    An approach to formulate geometric relations among distances between nodes as equality constraints is introduced in this paper to study the localization problem with imprecise distance information in sensor networks. These constraints can be further used to formulate optimization problems for distan

  20. Peer effects and local congestion in networks

    NARCIS (Netherlands)

    Currarini, Sergio; Fumagalli, E.; Panebianco, Fabrizio

    We study linear quadratic games played on a network. Agents face peer effects with distance-one neighbors, and strategic substitution with distance-two neighbors (local congestion). For this class of games, we show that an interior equilibrium exists both in the high and in the low regions of the

  1. Parallel computing and networking; Heiretsu keisanki to network

    Energy Technology Data Exchange (ETDEWEB)

    Asakawa, E.; Tsuru, T. [Japan National Oil Corp., Tokyo (Japan); Matsuoka, T. [Japan Petroleum Exploration Co. Ltd., Tokyo (Japan)

    1996-05-01

    This paper describes the trend of parallel computers used in geophysical exploration. Around 1993 was the early days when the parallel computers began to be used for geophysical exploration. Classification of these computers those days was mainly MIMD (multiple instruction stream, multiple data stream), SIMD (single instruction stream, multiple data stream) and the like. Parallel computers were publicized in the 1994 meeting of the Geophysical Exploration Society as a `high precision imaging technology`. Concerning the library of parallel computers, there was a shift to PVM (parallel virtual machine) in 1993 and to MPI (message passing interface) in 1995. In addition, the compiler of FORTRAN90 was released with support implemented for data parallel and vector computers. In 1993, networks used were Ethernet, FDDI, CDDI and HIPPI. In 1995, the OC-3 products under ATM began to propagate. However, ATM remains to be an interoffice high speed network because the ATM service has not spread yet for the public network. 1 ref.

  2. Local Area Network Performance Using UML

    Directory of Open Access Journals (Sweden)

    Dr Vipin Saxena

    2010-09-01

    Full Text Available This paper explains the performance of LAN/WAN using UML. Nowadays, Local Area Network (LAN System is an integral part of any organization. This may established by the use of the fiber optics cables or through Wi-Fi connectivity called as Wireless Local Area Network (WLAN. In the network connectivity, administrator has to ensure whether the destination node is receiving the data correctly, safely and within minimum time period. In the country, many of the organizations have the LAN or WLAN but one has to check the performance of these, therefore, in this paper, performance of LAN/WLAN is observed through the UML design. The node is considered as a stereotype and one process is transmitted from one machine to the other machine and data transmission rate is recorded through experimental study. A real case study of Babasaheb Bhimrao Ambedkar Central University is considered and results are depicted in the form of graphs and table.

  3. Scaling in Computer Network Traffic

    Science.gov (United States)

    2007-11-02

    Laboratory for Applied Network Research). ♠ CAIDA (Cooperative Association for Internet Data Analysis). ♥ ♠ WAND (Waikato Applied Network Dynamics [DAG...permission of CAIDA , c© 2001 CAIDA /UC Regents. Mapnet Author: Bradley Huffaker. 15 Flows and Packets Flows are sets of packets associated to the same data

  4. Computer Forensic Using Lazy Local Bagging Predictors

    Institute of Scientific and Technical Information of China (English)

    QIU Wei-dong; BAO Cheng-yi; ZHU Xing-quan

    2009-01-01

    In this paper, we study the problem of employ ensemble learning for computer forensic. We propose a Lazy Local Learning based bagging (L3B) approach, where base learners are trained from a small instance subset surrounding each test instance. More specifically, given a test instance x, L3B first discovers x's k nearest neighbours, and then applies progressive sampling to the selected neighbours to train a set of base classifiers, by using a given very weak (VW) learner. At the last stage, x is labeled as the most frequently voted class of all base classifiers. Finally, we apply the proposed L3B to computer forensic.

  5. Updating Road Networks by Local Renewal from GPS Trajectories

    Directory of Open Access Journals (Sweden)

    Tao Wu

    2016-09-01

    Full Text Available The long production cycle and huge cost of collecting road network data often leave the data lagging behind the latest real conditions. However, this situation is rapidly changing as the positioning techniques ubiquitously used in mobile devices are gradually being implemented in road network research and applications. Currently, the predominant approaches infer road networks from mobile location information (e.g., GPS trajectory data directly using various extracting algorithms, which leads to expensive consumption of computational resources in the case of large-scale areas. For this reason, we propose an alternative that renews road networks with a novel spiral strategy, including a hidden Markov model (HMM for detecting potential problems in existing road network data and a method to update the data, on the local scale, by generating new road segments from trajectory data. The proposed approach reduces computation costs on roads with completed or updated information by updating problem road segments in the minimum range of the road network. We evaluated the performance of our proposals using GPS traces collected from taxies and OpenStreetMap (OSM road networks covering urban areas of Wuhan City.

  6. Mobile Node Localization in Cellular Networks

    Directory of Open Access Journals (Sweden)

    Yasir Malik

    2012-01-01

    Full Text Available Location information is the major component in location based applications. This information is used in different safety and service oriented applications to provide users with services according to their Geolocation. There are many approaches to locate mobile nodes in indoor and outdoor environments. In thispaper, we are interested in outdoor localization particularly in cellular networks of mobile nodes andpresented a localization method based on cell and user location information. Our localization method is based on hello message delay (sending and receiving time and coordinate information of Base Transceiver Station (BTSs. To validate our method across cellular network, we implemented and simulated our method in two scenarios i.e. maintaining database of base stations in centralize and distributed system. Simulation results show the effectiveness of our approach and its implementation applicability in telecommunication systems.

  7. Mobile node localization in cellular networks

    CERN Document Server

    Malik, Yasir; Abdulrazak, Bessam; Tariq, Usman; 10.5121/ijwmn.2011.3607

    2012-01-01

    Location information is the major component in location based applications. This information is used in different safety and service oriented applications to provide users with services according to their Geolocation. There are many approaches to locate mobile nodes in indoor and outdoor environments. In this paper, we are interested in outdoor localization particularly in cellular networks of mobile nodes and presented a localization method based on cell and user location information. Our localization method is based on hello message delay (sending and receiving time) and coordinate information of Base Transceiver Station (BTSs). To validate our method across cellular network, we implemented and simulated our method in two scenarios i.e. maintaining database of base stations in centralize and distributed system. Simulation results show the effectiveness of our approach and its implementation applicability in telecommunication systems.

  8. Computer networking a top-down approach

    CERN Document Server

    Kurose, James

    2017-01-01

    Unique among computer networking texts, the Seventh Edition of the popular Computer Networking: A Top Down Approach builds on the author’s long tradition of teaching this complex subject through a layered approach in a “top-down manner.” The text works its way from the application layer down toward the physical layer, motivating readers by exposing them to important concepts early in their study of networking. Focusing on the Internet and the fundamentally important issues of networking, this text provides an excellent foundation for readers interested in computer science and electrical engineering, without requiring extensive knowledge of programming or mathematics. The Seventh Edition has been updated to reflect the most important and exciting recent advances in networking.

  9. Current Computer Network Security Issues/Threats

    National Research Council Canada - National Science Library

    Ammar Yassir; Alaa A K Ismaeel

    2016-01-01

    Computer network security has been a subject of concern for a long period. Many efforts have been made to address the existing and emerging threats such as viruses and Trojan among others without any significant success...

  10. Low Computational Complexity Network Coding For Mobile Networks

    DEFF Research Database (Denmark)

    Heide, Janus

    2012-01-01

    Network Coding (NC) is a technique that can provide benefits in many types of networks, some examples from wireless networks are: In relay networks, either the physical or the data link layer, to reduce the number of transmissions. In reliable multicast, to reduce the amount of signaling and enable...... cooperation among receivers. In meshed networks, to simplify routing schemes and to increase robustness toward node failures. This thesis deals with implementation issues of one NC technique namely Random Linear Network Coding (RLNC) which can be described as a highly decentralized non-deterministic intra......-flow coding technique. One of the key challenges of this technique is its inherent computational complexity which can lead to high computational load and energy consumption in particular on the mobile platforms that are the target platform in this work. To increase the coding throughput several...

  11. A robust localization algorithm in wireless sensor networks

    Institute of Scientific and Technical Information of China (English)

    Xin LI; Bei HUA; Yi SHANG; Yan XIONG

    2008-01-01

    Most of the state-of-the-art localization algo-rithms in wireless sensor networks (WSNs) are vulnerable to various kinds of location attacks, whereas secure local-ization schemes proposed so far are too complex to apply to power constrained WSNs. This paper provides a distributed robust localization algorithm called Bilateration that employs a unified way to deal with all kinds of location attacks as well as other kinds of information distortion caused by node malfunction or abnormal environmental noise. Bilateration directly calculates two candidate posi-tions for every two heard anchors, and then uses the aver-age of a maximum set of close-by candidate positions as the location estimation. The basic idea behind Bilateration is that candidate positions calculated from reasonable (I.e.,error bounded) anchor positions and distance measure-ments tend to be close to each other, whereas candidate positions calculated from false anchor positions or distance measurements are highly unlikely to be close to each other if false information are not collaborated. By using ilateration instead of classical multilateration to compute location estimation, Bilateration requires much lower computa-tional complexity, yet still retains the same localization accuracy. This paper also evaluates and compares Bilateration with three multilateration-based localization algorithms, and the simulation results show that Bilateration achieves the best comprehensive performance and is more suitable to real wireless sensor networks.

  12. Networked Computing in Wireless Sensor Networks for Structural Health Monitoring

    CERN Document Server

    Jindal, Apoorva

    2010-01-01

    This paper studies the problem of distributed computation over a network of wireless sensors. While this problem applies to many emerging applications, to keep our discussion concrete we will focus on sensor networks used for structural health monitoring. Within this context, the heaviest computation is to determine the singular value decomposition (SVD) to extract mode shapes (eigenvectors) of a structure. Compared to collecting raw vibration data and performing SVD at a central location, computing SVD within the network can result in significantly lower energy consumption and delay. Using recent results on decomposing SVD, a well-known centralized operation, into components, we seek to determine a near-optimal communication structure that enables the distribution of this computation and the reassembly of the final results, with the objective of minimizing energy consumption subject to a computational delay constraint. We show that this reduces to a generalized clustering problem; a cluster forms a unit on w...

  13. Computer Networks and African Studies Centers.

    Science.gov (United States)

    Kuntz, Patricia S.

    The use of electronic communication in the 12 Title VI African Studies Centers is discussed, and the networks available for their use are reviewed. It is argued that the African Studies Centers should be on the cutting edge of contemporary electronic communication and that computer networks should be a fundamental aspect of their programs. An…

  14. Computational social networks tools, perspectives and applications

    CERN Document Server

    Abraham, Ajith

    2012-01-01

    Provides the latest advances in computational social networks, and illustrates how organizations can gain a competitive advantage by applying these ideas in real-world scenarios Presents a specific focus on practical tools and applications Provides experience reports, survey articles, and intelligence techniques and theories relating to specific problems in network technology

  15. Quantum state diffusion, localization and computation

    CERN Document Server

    Schack, R; Percival, I C

    1995-01-01

    Numerical simulation of individual open quantum systems has proven advantages over density operator computations. Quantum state diffusion with a moving basis (MQSD) provides a practical numerical simulation method which takes full advantage of the localization of quantum states into wave packets occupying small regions of classical phase space. Following and extending the original proposal of Percival, Alber and Steimle, we show that MQSD can provide a further gain over ordinary QSD and other quantum trajectory methods of many orders of magnitude in computational space and time. Because of these gains, it is even possible to calculate an open quantum system trajectory when the corresponding isolated system is intractable. MQSD is particularly advantageous where classical or semiclassical dynamics provides an adequate qualitative picture but is numerically inaccurate because of significant quantum effects. The principles are illustrated by computations for the quantum Duffing oscillator and for second harmonic...

  16. Integrating Network Management for Cloud Computing Services

    Science.gov (United States)

    2015-06-01

    azure.microsoft.com/. 114 [16] Microsoft Azure ExpressRoute. http://azure.microsoft.com/en-us/ services/expressroute/. [17] Mobility and Networking...Marc Lobelle. The NAROS Ap- proach for IPv6 Multihoming with Traffic Engineering. In Quality for All, pages 112–121. Springer, 2003. [57] Jeffrey Dean...Networking Technologies, Services, and Protocols; Performance of Computer and Commu- nication Networks; Mobile and Wireless Communications Systems

  17. Finding local communities in protein networks

    Directory of Open Access Journals (Sweden)

    Teng Shang-Hua

    2009-09-01

    Full Text Available Abstract Background Protein-protein interactions (PPIs play fundamental roles in nearly all biological processes, and provide major insights into the inner workings of cells. A vast amount of PPI data for various organisms is available from BioGRID and other sources. The identification of communities in PPI networks is of great interest because they often reveal previously unknown functional ties between proteins. A large number of global clustering algorithms have been applied to protein networks, where the entire network is partitioned into clusters. Here we take a different approach by looking for local communities in PPI networks. Results We develop a tool, named Local Protein Community Finder, which quickly finds a community close to a queried protein in any network available from BioGRID or specified by the user. Our tool uses two new local clustering algorithms Nibble and PageRank-Nibble, which look for a good cluster among the most popular destinations of a short random walk from the queried vertex. The quality of a cluster is determined by proportion of outgoing edges, known as conductance, which is a relative measure particularly useful in undersampled networks. We show that the two local clustering algorithms find communities that not only form excellent clusters, but are also likely to be biologically relevant functional components. We compare the performance of Nibble and PageRank-Nibble to other popular and effective graph partitioning algorithms, and show that they find better clusters in the graph. Moreover, Nibble and PageRank-Nibble find communities that are more functionally coherent. Conclusion The Local Protein Community Finder, accessible at http://xialab.bu.edu/resources/lpcf, allows the user to quickly find a high-quality community close to a queried protein in any network available from BioGRID or specified by the user. We show that the communities found by our tool form good clusters and are functionally coherent

  18. Wireless Networks: New Meaning to Ubiquitous Computing.

    Science.gov (United States)

    Drew, Wilfred, Jr.

    2003-01-01

    Discusses the use of wireless technology in academic libraries. Topics include wireless networks; standards (IEEE 802.11); wired versus wireless; why libraries implement wireless technology; wireless local area networks (WLANs); WLAN security; examples of wireless use at Indiana State University and Morrisville College (New York); and useful…

  19. RELAY ALGORITHM BASED ON NETWORK CODING IN WIRELESS LOCAL NETWORK

    Institute of Scientific and Technical Information of China (English)

    Wang Qi; Wang Qingshan; Wang Dongxue

    2013-01-01

    The network coding is a new technology in the field of information in 21st century.It could enhance the network throughput and save the energy consumption,and is mainly based on the single transmission rate.However,with the development of wireless network and equipment,wireless local network MAC protocols have already supported the multi-rate transmission.This paper investigates the optimal relay selection problem based on network coding.Firstly,the problem is formulated as an optimization problem.Moreover,a relay algorithm based on network coding is proposed and the transmission time gain of our algorithm over the traditional relay algorithm is analyzed.Lastly,we compare total transmission time and the energy consumption of our proposed algorithm,Network Coding with Relay Assistance (NCRA),Transmission Request (TR),and the Direct Transmission (DT) without relay algorithm by adopting IEEE 802.11b.The simulation results demonstrate that our algorithm that improves the coding opportunity by the cooperation of the relay nodes leads to the transmission time decrease of up to 17% over the traditional relay algorithms.

  20. Probing many-body localization with neural networks

    Science.gov (United States)

    Schindler, Frank; Regnault, Nicolas; Neupert, Titus

    2017-06-01

    We show that a simple artificial neural network trained on entanglement spectra of individual states of a many-body quantum system can be used to determine the transition between a many-body localized and a thermalizing regime. Specifically, we study the Heisenberg spin-1/2 chain in a random external field. We employ a multilayer perceptron with a single hidden layer, which is trained on labeled entanglement spectra pertaining to the fully localized and fully thermal regimes. We then apply this network to classify spectra belonging to states in the transition region. For training, we use a cost function that contains, in addition to the usual error and regularization parts, a term that favors a confident classification of the transition region states. The resulting phase diagram is in good agreement with the one obtained by more conventional methods and can be computed for small systems. In particular, the neural network outperforms conventional methods in classifying individual eigenstates pertaining to a single disorder realization. It allows us to map out the structure of these eigenstates across the transition with spatial resolution. Furthermore, we analyze the network operation using the dreaming technique to show that the neural network correctly learns by itself the power-law structure of the entanglement spectra in the many-body localized regime.

  1. Non-Hermitian localization in biological networks

    Science.gov (United States)

    Amir, Ariel; Hatano, Naomichi; Nelson, David R.

    2016-04-01

    We explore the spectra and localization properties of the N -site banded one-dimensional non-Hermitian random matrices that arise naturally in sparse neural networks. Approximately equal numbers of random excitatory and inhibitory connections lead to spatially localized eigenfunctions and an intricate eigenvalue spectrum in the complex plane that controls the spontaneous activity and induced response. A finite fraction of the eigenvalues condense onto the real or imaginary axes. For large N , the spectrum has remarkable symmetries not only with respect to reflections across the real and imaginary axes but also with respect to 90∘ rotations, with an unusual anisotropic divergence in the localization length near the origin. When chains with periodic boundary conditions become directed, with a systematic directional bias superimposed on the randomness, a hole centered on the origin opens up in the density-of-states in the complex plane. All states are extended on the rim of this hole, while the localized eigenvalues outside the hole are unchanged. The bias-dependent shape of this hole tracks the bias-independent contours of constant localization length. We treat the large-N limit by a combination of direct numerical diagonalization and using transfer matrices, an approach that allows us to exploit an electrostatic analogy connecting the "charges" embodied in the eigenvalue distribution with the contours of constant localization length. We show that similar results are obtained for more realistic neural networks that obey "Dale's law" (each site is purely excitatory or inhibitory) and conclude with perturbation theory results that describe the limit of large directional bias, when all states are extended. Related problems arise in random ecological networks and in chains of artificial cells with randomly coupled gene expression patterns.

  2. Autonomic computing enabled cooperative networked design

    CERN Document Server

    Wodczak, Michal

    2014-01-01

    This book introduces the concept of autonomic computing driven cooperative networked system design from an architectural perspective. As such it leverages and capitalises on the relevant advancements in both the realms of autonomic computing and networking by welding them closely together. In particular, a multi-faceted Autonomic Cooperative System Architectural Model is defined which incorporates the notion of Autonomic Cooperative Behaviour being orchestrated by the Autonomic Cooperative Networking Protocol of a cross-layer nature. The overall proposed solution not only advocates for the inc

  3. Architecture Design & Network Application of Cloud Computing

    Directory of Open Access Journals (Sweden)

    Mehzabul Hoque Nahid

    2015-08-01

    Full Text Available “Cloud” computing a comparatively term, stands on decades of research & analysis in virtualization, analytical distributed computing, utility computing, and more recently computer networking, web technology and software services. Cloud computing represents a shift away from computing as a product that is purchased, to computing as a service that is delivered to consumers over the internet from large-scale data centers – or “clouds”. Whilst cloud computing is obtaining growing popularity in the IT industry, academic appeared to be lagging behind the developments in this field. It also implies a service oriented designed architecture, reduced information technology overhead for the end-user, good flexibility, reduced total cost of private ownership, on-demand services and many other things. This paper discusses the concept of “cloud” computing, some of the issues it tries to address, related research topics, and a “cloud” implementation available today

  4. Cross-Industry Spatially Localized Innovation Networks

    Directory of Open Access Journals (Sweden)

    Aleksandr Evseevich Karlik

    2016-12-01

    Full Text Available This article’s objective is to develop conceptual approach to the study of key decision-making factors of cross-industry spatially localized innovation networks regularities by the application of quantitative and qualitative data of St. Petersburg Innovation and Technology Cluster of Machinery Manufacturing and Metalworking. The paper is based on the previous research findings which conclude that such networks have a set of opportunities and constraints for innovation. The hypothesis is that in the clusters, representing a special type of these networks, the spatial proximity partly offsets the negative impact of industrial distance. The authors propose a structural and logical model of strategic decision-making to analyze these effects on innovation. They specify network’s influences on performance: cognitive diversity; knowledge and expertise; structural autonomy and equivalence. The model is applied to spatially localized cross-industry cluster and then improved in accordance with the obtained results for accounting resource flows. It allowed to take into account the dynamics of innovation activity and to develop the practical implications in the particular business context. The analysis identified the peculiarities of spatially localized crossindustry innovation cooperation in perspective of the combinations of tangible resources, information and other intangible resources for the renewal of mature industries. The research results can be used in business as well as in industrial and regional economic policy. In the conclusion, the article outlines future research directions: a comprehensive empirical study with the analysis of data on the factors of cross-industry cooperation which were identified in this paper with testing of causal relations; the developing an approach to the study of spatially localized networks based on the exchange of primary resources in the economic system stability framework.

  5. Algorithms and networking for computer games

    CERN Document Server

    Smed, Jouni

    2006-01-01

    Algorithms and Networking for Computer Games is an essential guide to solving the algorithmic and networking problems of modern commercial computer games, written from the perspective of a computer scientist. Combining algorithmic knowledge and game-related problems, the authors discuss all the common difficulties encountered in game programming. The first part of the book tackles algorithmic problems by presenting how they can be solved practically. As well as ""classical"" topics such as random numbers, tournaments and game trees, the authors focus on how to find a path in, create the terrai

  6. Computer network time synchronization the network time protocol

    CERN Document Server

    Mills, David L

    2006-01-01

    What started with the sundial has, thus far, been refined to a level of precision based on atomic resonance: Time. Our obsession with time is evident in this continued scaling down to nanosecond resolution and beyond. But this obsession is not without warrant. Precision and time synchronization are critical in many applications, such as air traffic control and stock trading, and pose complex and important challenges in modern information networks.Penned by David L. Mills, the original developer of the Network Time Protocol (NTP), Computer Network Time Synchronization: The Network Time Protocol

  7. Social networks a framework of computational intelligence

    CERN Document Server

    Chen, Shyi-Ming

    2014-01-01

    This volume provides the audience with an updated, in-depth and highly coherent material on the conceptually appealing and practically sound information technology of Computational Intelligence applied to the analysis, synthesis and evaluation of social networks. The volume involves studies devoted to key issues of social networks including community structure detection in networks, online social networks, knowledge growth and evaluation, and diversity of collaboration mechanisms.  The book engages a wealth of methods of Computational Intelligence along with well-known techniques of linear programming, Formal Concept Analysis, machine learning, and agent modeling.  Human-centricity is of paramount relevance and this facet manifests in many ways including personalized semantics, trust metric, and personal knowledge management; just to highlight a few of these aspects. The contributors to this volume report on various essential applications including cyber attacks detection, building enterprise social network...

  8. Spreading to localized targets in complex networks

    Science.gov (United States)

    Sun, Ye; Ma, Long; Zeng, An; Wang, Wen-Xu

    2016-12-01

    As an important type of dynamics on complex networks, spreading is widely used to model many real processes such as the epidemic contagion and information propagation. One of the most significant research questions in spreading is to rank the spreading ability of nodes in the network. To this end, substantial effort has been made and a variety of effective methods have been proposed. These methods usually define the spreading ability of a node as the number of finally infected nodes given that the spreading is initialized from the node. However, in many real cases such as advertising and news propagation, the spreading only aims to cover a specific group of nodes. Therefore, it is necessary to study the spreading ability of nodes towards localized targets in complex networks. In this paper, we propose a reversed local path algorithm for this problem. Simulation results show that our method outperforms the existing methods in identifying the influential nodes with respect to these localized targets. Moreover, the influential spreaders identified by our method can effectively avoid infecting the non-target nodes in the spreading process.

  9. Localization of troubles in telephone cable networks

    Energy Technology Data Exchange (ETDEWEB)

    Chuxin Chen; Hollidge, T.L.; Sharma, D.D. [Pacific Bell, San Ramon, CA (United States)

    1996-12-31

    This paper describes an intelligent system which detects the location of troubles in a local telephone cable network. Such a task is very challenging, tedious, and requires human experts with years of experience and high analytical skills. Our system captures the expertise and knowledge required for this task, along with automated access to database systems, so that the system can help a human analyst to pin-point network trouble location more efficiently and accurately, ultimately reducing the cost of maintenance and repair. The system utilizes probabilistic reasoning techniques and logical operators to determine which plant component has the highest failure probability. This is achieved by building a topology of the local cable network, constructing a causal net which contains belief of failure for each plant component, given their current status, history data, cable pair distribution, and connectivity to other components. The Trouble Localization (TL) Module described in this paper is a crucial part of a larger system: Outside Plant Analysis System (OPAS) which has been deployed Statewide for over nine months at Pacific Bell PMAC centers. The TL system module utilizes AI and Object-Oriented technology. It is implemented in C++ on Unix workstations, and its graphical user interface is in an X Window environment.

  10. Requirement emergence computation of networked software

    Institute of Scientific and Technical Information of China (English)

    HE Keqing; LIANG Peng; PENG Rong; LI Bing; LIU Jing

    2007-01-01

    Emergence Computation has become a hot topic in the research of complex systems in recent years.With the substantial increase in scale and complexity of network-based information systems,the uncertain user requirements from the Internet and personalized application requirement result in the frequent change for the software requirement.Meanwhile,the software system with non self-possessed,resource become more and more complex.Furthermore,the interaction and cooperation requirement between software units and running environment in service computing increase the complexity of software systems.The software systems with complex system characteristics are developing into the"Networked Software" with characteristics of change-on-demand and change-with-cooperation.The concepts "programming","compiling" and "running"of software in common sense are extended from "desktop" to "network".The core issue of software engineering is moving to the requirement engineering,which becomes the research focus of complex systemsoftware engineering.In this paper,we present the software network view based on complex system theory,and the concept of networked software and networked requirement.We proposethe challenge problem in the research of emergence computation of networked software requirement.A hierarchical & cooperative Unified requirement modeling framework URF (Unified Requirement Framework) and related RGPS (Role,Goal,Process and Service) meta-models are proposed.Five scales and the evolutionary growth mechanismin requirement emergence computation of networked software are given with focus on user-dominant and domain-oriented requirement,and the rules and predictability in requirement emergence computation are analyzed.A case study in the application of networked e-Business with evolutionary growth based on State design pattern is presented in the end.

  11. Evaluation of Network Reliability for Computer Networks with Multiple Sources

    Directory of Open Access Journals (Sweden)

    Yi-Kuei Lin

    2012-01-01

    Full Text Available Evaluating the reliability of a network with multiple sources to multiple sinks is a critical issue from the perspective of quality management. Due to the unrealistic definition of paths of network models in previous literature, existing models are not appropriate for real-world computer networks such as the Taiwan Advanced Research and Education Network (TWAREN. This paper proposes a modified stochastic-flow network model to evaluate the network reliability of a practical computer network with multiple sources where data is transmitted through several light paths (LPs. Network reliability is defined as being the probability of delivering a specified amount of data from the sources to the sink. It is taken as a performance index to measure the service level of TWAREN. This paper studies the network reliability of the international portion of TWAREN from two sources (Taipei and Hsinchu to one sink (New York that goes through a submarine and land surface cable between Taiwan and the United States.

  12. Computer Vision Using Local Binary Patterns

    CERN Document Server

    Pietikainen, Matti; Zhao, Guoying; Ahonen, Timo

    2011-01-01

    The recent emergence of Local Binary Patterns (LBP) has led to significant progress in applying texture methods to various computer vision problems and applications. The focus of this research has broadened from 2D textures to 3D textures and spatiotemporal (dynamic) textures. Also, where texture was once utilized for applications such as remote sensing, industrial inspection and biomedical image analysis, the introduction of LBP-based approaches have provided outstanding results in problems relating to face and activity analysis, with future scope for face and facial expression recognition, b

  13. Localization with a Mobile Beacon in Underwater Acoustic Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sangho Lee

    2012-04-01

    Full Text Available Localization is one of the most important issues associated with underwater acoustic sensor networks, especially when sensor nodes are randomly deployed. Given that it is difficult to deploy beacon nodes at predetermined locations, localization schemes with a mobile beacon on the sea surface or along the planned path are inherently convenient, accurate, and energy-efficient. In this paper, we propose a new range-free Localization with a Mobile Beacon (LoMoB. The mobile beacon periodically broadcasts a beacon message containing its location. Sensor nodes are individually localized by passively receiving the beacon messages without inter-node communications. For location estimation, a set of potential locations are obtained as candidates for a node’s location and then the node’s location is determined through the weighted mean of all the potential locations with the weights computed based on residuals.

  14. Localization with a mobile beacon in underwater acoustic sensor networks.

    Science.gov (United States)

    Lee, Sangho; Kim, Kiseon

    2012-01-01

    Localization is one of the most important issues associated with underwater acoustic sensor networks, especially when sensor nodes are randomly deployed. Given that it is difficult to deploy beacon nodes at predetermined locations, localization schemes with a mobile beacon on the sea surface or along the planned path are inherently convenient, accurate, and energy-efficient. In this paper, we propose a new range-free Localization with a Mobile Beacon (LoMoB). The mobile beacon periodically broadcasts a beacon message containing its location. Sensor nodes are individually localized by passively receiving the beacon messages without inter-node communications. For location estimation, a set of potential locations are obtained as candidates for a node's location and then the node's location is determined through the weighted mean of all the potential locations with the weights computed based on residuals.

  15. Professional networking using computer-mediated communication.

    Science.gov (United States)

    Washer, Peter

    Traditionally, professionals have networked with others in their field through attending conferences, professional organizations, direct mailing, and via the workplace. Recently, there have been new possibilities to network with other professionals using the internet. This article looks at the possibilities that the internet offers for professional networking, particularly e-mailing lists, newsgroups and membership databases, and compares them against more traditional methods of professional networking. The different types of computer-mediated communication are discussed and their relative merits and disadvantages are examined. The benefits and potential pitfalls of internet professional networking, as it relates to the nursing profession, are examined. Practical advice is offered on how the internet can be used as a means to foster professional networks of academic, clinical or research interests.

  16. Underwater Electromagnetic Sensor Networks, Part II: Localization and Network Simulations

    Directory of Open Access Journals (Sweden)

    Javier Zazo

    2016-12-01

    Full Text Available In the first part of the paper, we modeled and characterized the underwater radio channel in shallowwaters. In the second part,we analyze the application requirements for an underwaterwireless sensor network (U-WSN operating in the same environment and perform detailed simulations. We consider two localization applications, namely self-localization and navigation aid, and propose algorithms that work well under the specific constraints associated with U-WSN, namely low connectivity, low data rates and high packet loss probability. We propose an algorithm where the sensor nodes collaboratively estimate their unknown positions in the network using a low number of anchor nodes and distance measurements from the underwater channel. Once the network has been self-located, we consider a node estimating its position for underwater navigation communicating with neighboring nodes. We also propose a communication system and simulate the whole electromagnetic U-WSN in the Castalia simulator to evaluate the network performance, including propagation impairments (e.g., noise, interference, radio parameters (e.g., modulation scheme, bandwidth, transmit power, hardware limitations (e.g., clock drift, transmission buffer and complete MAC and routing protocols. We also explain the changes that have to be done to Castalia in order to perform the simulations. In addition, we propose a parametric model of the communication channel that matches well with the results from the first part of this paper. Finally, we provide simulation results for some illustrative scenarios.

  17. Underwater Electromagnetic Sensor Networks, Part II: Localization and Network Simulations.

    Science.gov (United States)

    Zazo, Javier; Macua, Sergio Valcarcel; Zazo, Santiago; Pérez, Marina; Pérez-Álvarez, Iván; Jiménez, Eugenio; Cardona, Laura; Brito, Joaquín Hernández; Quevedo, Eduardo

    2016-12-17

    In the first part of the paper, we modeled and characterized the underwater radio channel in shallowwaters. In the second part,we analyze the application requirements for an underwaterwireless sensor network (U-WSN) operating in the same environment and perform detailed simulations. We consider two localization applications, namely self-localization and navigation aid, and propose algorithms that work well under the specific constraints associated with U-WSN, namely low connectivity, low data rates and high packet loss probability. We propose an algorithm where the sensor nodes collaboratively estimate their unknown positions in the network using a low number of anchor nodes and distance measurements from the underwater channel. Once the network has been self-located, we consider a node estimating its position for underwater navigation communicating with neighboring nodes. We also propose a communication system and simulate the whole electromagnetic U-WSN in the Castalia simulator to evaluate the network performance, including propagation impairments (e.g., noise, interference), radio parameters (e.g., modulation scheme, bandwidth, transmit power), hardware limitations (e.g., clock drift, transmission buffer) and complete MAC and routing protocols. We also explain the changes that have to be done to Castalia in order to perform the simulations. In addition, we propose a parametric model of the communication channel that matches well with the results from the first part of this paper. Finally, we provide simulation results for some illustrative scenarios.

  18. Underwater Electromagnetic Sensor Networks, Part II: Localization and Network Simulations

    Science.gov (United States)

    Zazo, Javier; Valcarcel Macua, Sergio; Zazo, Santiago; Pérez, Marina; Pérez-Álvarez, Iván; Jiménez, Eugenio; Cardona, Laura; Brito, Joaquín Hernández; Quevedo, Eduardo

    2016-01-01

    In the first part of the paper, we modeled and characterized the underwater radio channel in shallow waters. In the second part, we analyze the application requirements for an underwater wireless sensor network (U-WSN) operating in the same environment and perform detailed simulations. We consider two localization applications, namely self-localization and navigation aid, and propose algorithms that work well under the specific constraints associated with U-WSN, namely low connectivity, low data rates and high packet loss probability. We propose an algorithm where the sensor nodes collaboratively estimate their unknown positions in the network using a low number of anchor nodes and distance measurements from the underwater channel. Once the network has been self-located, we consider a node estimating its position for underwater navigation communicating with neighboring nodes. We also propose a communication system and simulate the whole electromagnetic U-WSN in the Castalia simulator to evaluate the network performance, including propagation impairments (e.g., noise, interference), radio parameters (e.g., modulation scheme, bandwidth, transmit power), hardware limitations (e.g., clock drift, transmission buffer) and complete MAC and routing protocols. We also explain the changes that have to be done to Castalia in order to perform the simulations. In addition, we propose a parametric model of the communication channel that matches well with the results from the first part of this paper. Finally, we provide simulation results for some illustrative scenarios. PMID:27999309

  19. Machine learning based Intelligent cognitive network using fog computing

    Science.gov (United States)

    Lu, Jingyang; Li, Lun; Chen, Genshe; Shen, Dan; Pham, Khanh; Blasch, Erik

    2017-05-01

    In this paper, a Cognitive Radio Network (CRN) based on artificial intelligence is proposed to distribute the limited radio spectrum resources more efficiently. The CRN framework can analyze the time-sensitive signal data close to the signal source using fog computing with different types of machine learning techniques. Depending on the computational capabilities of the fog nodes, different features and machine learning techniques are chosen to optimize spectrum allocation. Also, the computing nodes send the periodic signal summary which is much smaller than the original signal to the cloud so that the overall system spectrum source allocation strategies are dynamically updated. Applying fog computing, the system is more adaptive to the local environment and robust to spectrum changes. As most of the signal data is processed at the fog level, it further strengthens the system security by reducing the communication burden of the communications network.

  20. LANES - LOCAL AREA NETWORK EXTENSIBLE SIMULATOR

    Science.gov (United States)

    Gibson, J.

    1994-01-01

    The Local Area Network Extensible Simulator (LANES) provides a method for simulating the performance of high speed local area network (LAN) technology. LANES was developed as a design and analysis tool for networking on board the Space Station. The load, network, link and physical layers of a layered network architecture are all modeled. LANES models to different lower-layer protocols, the Fiber Distributed Data Interface (FDDI) and the Star*Bus. The load and network layers are included in the model as a means of introducing upper-layer processing delays associated with message transmission; they do not model any particular protocols. FDDI is an American National Standard and an International Organization for Standardization (ISO) draft standard for a 100 megabit-per-second fiber-optic token ring. Specifications for the LANES model of FDDI are taken from the Draft Proposed American National Standard FDDI Token Ring Media Access Control (MAC), document number X3T9.5/83-16 Rev. 10, February 28, 1986. This is a mature document describing the FDDI media-access-control protocol. Star*Bus, also known as the Fiber Optic Demonstration System, is a protocol for a 100 megabit-per-second fiber-optic star-topology LAN. This protocol, along with a hardware prototype, was developed by Sperry Corporation under contract to NASA Goddard Space Flight Center as a candidate LAN protocol for the Space Station. LANES can be used to analyze performance of a networking system based on either FDDI or Star*Bus under a variety of loading conditions. Delays due to upper-layer processing can easily be nullified, allowing analysis of FDDI or Star*Bus as stand-alone protocols. LANES is a parameter-driven simulation; it provides considerable flexibility in specifying both protocol an run-time parameters. Code has been optimized for fast execution and detailed tracing facilities have been included. LANES was written in FORTRAN 77 for implementation on a DEC VAX under VMS 4.6. It consists of two

  1. Towards structural controllability of local-world networks

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Shiwen, E-mail: sunsw80@126.com [Tianjin Key Laboratory of Intelligence Computing and Novel Software Technology, Tianjin University of Technology, Tianjin 300384 (China); Key Laboratory of Computer Vision and System (Tianjin University of Technology), Ministry of Education, Tianjin 300384 (China); Ma, Yilin; Wu, Yafang; Wang, Li; Xia, Chengyi [Tianjin Key Laboratory of Intelligence Computing and Novel Software Technology, Tianjin University of Technology, Tianjin 300384 (China); Key Laboratory of Computer Vision and System (Tianjin University of Technology), Ministry of Education, Tianjin 300384 (China)

    2016-05-20

    Controlling complex networks is of vital importance in science and engineering. Meanwhile, local-world effect is an important ingredient which should be taken into consideration in the complete description of real-world complex systems. In this letter, structural controllability of a class of local-world networks is investigated. Through extensive numerical simulations, firstly, effects of local world size M and network size N on structural controllability are examined. For local-world networks with sparse topological configuration, compared to network size, local-world size can induce stronger influence on controllability, however, for dense networks, controllability is greatly affected by network size and local-world effect can be neglected. Secondly, relationships between controllability and topological properties are analyzed. Lastly, the robustness of local-world networks under targeted attacks regarding structural controllability is discussed. These results can help to deepen the understanding of structural complexity and connectivity patterns of complex systems. - Highlights: • Structural controllability of a class of local-world networks is investigated. • For sparse local-world networks, compared to network size, local-world size can bring stronger influence on controllability. • For dense networks, controllability is greatly affected by network size and the effect of local-world size can be neglected. • Structural controllability against targeted node attacks is discussed.

  2. Localization in Wireless Networks Foundations and Applications

    CERN Document Server

    Sanford, Jessica Feng; Slijepcevic, Sasha

    2012-01-01

    In a computational tour-de-force, this volume wipes away a host of problems related to location discovery in wireless ad-hoc sensor networks. WASNs have recognized potential in many applications that are location-dependent, yet are heavily constrained by factors such as cost and energy consumption. Their “ad-hoc” nature, with direct rather than mediated connections between a network of wireless devices, adds another layer of difficulty.   Basing this work entirely on data-driven, coordinated algorithms, the authors' aim is to present location discovery techniques that are highly accurate—and which fit user criteria. The research deploys nonparametric statistical methods and relies on the concept of joint probability to construct error (including location error) models and environmental field models. It also addresses system issues such as the broadcast and scheduling of the beacon. Reporting an impressive accuracy gain of almost 17 percent, and organized in a clear, sequential manner, this book represe...

  3. Local self-uniformity in photonic networks

    Science.gov (United States)

    Sellers, Steven R.; Man, Weining; Sahba, Shervin; Florescu, Marian

    2017-01-01

    The interaction of a material with light is intimately related to its wavelength-scale structure. Simple connections between structure and optical response empower us with essential intuition to engineer complex optical functionalities. Here we develop local self-uniformity (LSU) as a measure of a random network's internal structural similarity, ranking networks on a continuous scale from crystalline, through glassy intermediate states, to chaotic configurations. We demonstrate that complete photonic bandgap structures possess substantial LSU and validate LSU's importance in gap formation through design of amorphous gyroid structures. Amorphous gyroid samples are fabricated via three-dimensional ceramic printing and the bandgaps experimentally verified. We explore also the wing-scale structuring in the butterfly Pseudolycaena marsyas and show that it possesses substantial amorphous gyroid character, demonstrating the subtle order achieved by evolutionary optimization and the possibility of an amorphous gyroid's self-assembly. PMID:28211466

  4. Network coding for computing: Linear codes

    CERN Document Server

    Appuswamy, Rathinakumar; Karamchandani, Nikhil; Zeger, Kenneth

    2011-01-01

    In network coding it is known that linear codes are sufficient to achieve the coding capacity in multicast networks and that they are not sufficient in general to achieve the coding capacity in non-multicast networks. In network computing, Rai, Dey, and Shenvi have recently shown that linear codes are not sufficient in general for solvability of multi-receiver networks with scalar linear target functions. We study single receiver networks where the receiver node demands a target function of the source messages. We show that linear codes may provide a computing capacity advantage over routing only when the receiver demands a `linearly-reducible' target function. % Many known target functions including the arithmetic sum, minimum, and maximum are not linearly-reducible. Thus, the use of non-linear codes is essential in order to obtain a computing capacity advantage over routing if the receiver demands a target function that is not linearly-reducible. We also show that if a target function is linearly-reducible,...

  5. International Symposium on Computing and Network Sustainability

    CERN Document Server

    Akashe, Shyam

    2017-01-01

    The book is compilation of technical papers presented at International Research Symposium on Computing and Network Sustainability (IRSCNS 2016) held in Goa, India on 1st and 2nd July 2016. The areas covered in the book are sustainable computing and security, sustainable systems and technologies, sustainable methodologies and applications, sustainable networks applications and solutions, user-centered services and systems and mobile data management. The novel and recent technologies presented in the book are going to be helpful for researchers and industries in their advanced works.

  6. Computation, cryptography, and network security

    CERN Document Server

    Rassias, Michael

    2015-01-01

    Analysis, assessment, and data management are core competencies for operation research analysts. This volume addresses a number of issues and developed methods for improving those skills. It is an outgrowth of a conference held in April 2013 at the Hellenic Military Academy, and brings together a broad variety of mathematical methods and theories with several applications. It discusses directions and pursuits of scientists that pertain to engineering sciences. It is also presents the theoretical background required for algorithms and techniques applied to a large variety of concrete problems. A number of open questions as well as new future areas are also highlighted.   This book will appeal to operations research analysts, engineers, community decision makers, academics, the military community, practitioners sharing the current “state-of-the-art,” and analysts from coalition partners. Topics covered include Operations Research, Games and Control Theory, Computational Number Theory and Information Securi...

  7. A spatially localized architecture for fast and modular DNA computing

    Science.gov (United States)

    Chatterjee, Gourab; Dalchau, Neil; Muscat, Richard A.; Phillips, Andrew; Seelig, Georg

    2017-09-01

    Cells use spatial constraints to control and accelerate the flow of information in enzyme cascades and signalling networks. Synthetic silicon-based circuitry similarly relies on spatial constraints to process information. Here, we show that spatial organization can be a similarly powerful design principle for overcoming limitations of speed and modularity in engineered molecular circuits. We create logic gates and signal transmission lines by spatially arranging reactive DNA hairpins on a DNA origami. Signal propagation is demonstrated across transmission lines of different lengths and orientations and logic gates are modularly combined into circuits that establish the universality of our approach. Because reactions preferentially occur between neighbours, identical DNA hairpins can be reused across circuits. Co-localization of circuit elements decreases computation time from hours to minutes compared to circuits with diffusible components. Detailed computational models enable predictive circuit design. We anticipate our approach will motivate using spatial constraints for future molecular control circuit designs.

  8. Traffic Dynamics of Computer Networks

    CERN Document Server

    Fekete, Attila

    2008-01-01

    Two important aspects of the Internet, namely the properties of its topology and the characteristics of its data traffic, have attracted growing attention of the physics community. My thesis has considered problems of both aspects. First I studied the stochastic behavior of TCP, the primary algorithm governing traffic in the current Internet, in an elementary network scenario consisting of a standalone infinite-sized buffer and an access link. The effect of the fast recovery and fast retransmission (FR/FR) algorithms is also considered. I showed that my model can be extended further to involve the effect of link propagation delay, characteristic of WAN. I continued my thesis with the investigation of finite-sized semi-bottleneck buffers, where packets can be dropped not only at the link, but also at the buffer. I demonstrated that the behavior of the system depends only on a certain combination of the parameters. Moreover, an analytic formula was derived that gives the ratio of packet loss rate at the buffer ...

  9. Student Motivation in Computer Networking Courses

    Directory of Open Access Journals (Sweden)

    Wen-Jung Hsin, PhD

    2007-08-01

    Full Text Available This paper introduces several hands-on projects that have been used to motivate students in learning various computer networking concepts. These projects are shown to be very useful and applicable to the learners’ daily tasks and activities such as emailing, Web browsing, and online shopping and banking, and lead to an unexpected byproduct, self-motivation.

  10. Student Motivation in Computer Networking Courses

    Directory of Open Access Journals (Sweden)

    Wen-Jung Hsin

    2007-01-01

    Full Text Available This paper introduces several hands-on projects that have been used to motivate students in learning various computer networking concepts. These projects are shown to be very useful and applicable to the learners’ daily tasks and activities such as emailing, Web browsing, and online shopping and banking, and lead to an unexpected byproduct, self-motivation.

  11. Student Motivation in Computer Networking Courses

    Science.gov (United States)

    Hsin, Wen-Jung

    2007-01-01

    This paper introduces several hands-on projects that have been used to motivate students in learning various computer networking concepts. These projects are shown to be very useful and applicable to the learners' daily tasks and activities such as emailing, Web browsing, and online shopping and banking, and lead to an unexpected byproduct,…

  12. Localization Algorithms of Underwater Wireless Sensor Networks: A Survey

    Science.gov (United States)

    Han, Guangjie; Jiang, Jinfang; Shu, Lei; Xu, Yongjun; Wang, Feng

    2012-01-01

    In Underwater Wireless Sensor Networks (UWSNs), localization is one of most important technologies since it plays a critical role in many applications. Motivated by widespread adoption of localization, in this paper, we present a comprehensive survey of localization algorithms. First, we classify localization algorithms into three categories based on sensor nodes’ mobility: stationary localization algorithms, mobile localization algorithms and hybrid localization algorithms. Moreover, we compare the localization algorithms in detail and analyze future research directions of localization algorithms in UWSNs. PMID:22438752

  13. Non-harmful insertion of data mimicking computer network attacks

    Science.gov (United States)

    Neil, Joshua Charles; Kent, Alexander; Hash, Jr, Curtis Lee

    2016-06-21

    Non-harmful data mimicking computer network attacks may be inserted in a computer network. Anomalous real network connections may be generated between a plurality of computing systems in the network. Data mimicking an attack may also be generated. The generated data may be transmitted between the plurality of computing systems using the real network connections and measured to determine whether an attack is detected.

  14. Advanced Scientific Computing Research Network Requirements

    Energy Technology Data Exchange (ETDEWEB)

    Bacon, Charles; Bell, Greg; Canon, Shane; Dart, Eli; Dattoria, Vince; Goodwin, Dave; Lee, Jason; Hicks, Susan; Holohan, Ed; Klasky, Scott; Lauzon, Carolyn; Rogers, Jim; Shipman, Galen; Skinner, David; Tierney, Brian

    2013-03-08

    The Energy Sciences Network (ESnet) is the primary provider of network connectivity for the U.S. Department of Energy (DOE) Office of Science (SC), the single largest supporter of basic research in the physical sciences in the United States. In support of SC programs, ESnet regularly updates and refreshes its understanding of the networking requirements of the instruments, facilities, scientists, and science programs that it serves. This focus has helped ESnet to be a highly successful enabler of scientific discovery for over 25 years. In October 2012, ESnet and the Office of Advanced Scientific Computing Research (ASCR) of the DOE SC organized a review to characterize the networking requirements of the programs funded by the ASCR program office. The requirements identified at the review are summarized in the Findings section, and are described in more detail in the body of the report.

  15. MAILROOM- A LOCAL AREA NETWORK ELECTRONIC MAIL PROGRAM

    Science.gov (United States)

    Weiner, M. J.

    1994-01-01

    The Mailroom program is a Local Area Network (LAN) electronic mail program. It allows LAN users to electronically exchange notes, letters, reminders, or any sort of communication via their computer. The Mailroom program links all LAN users into a communication circle where messages can be created, sent, copied, printed, downloaded, uploaded, and deleted through a series of menu-driven screens. Mailroom includes a feature which allows users to determine if a message they have sent has been read by the receiver. Each user must be separately installed and removed from Mailroom as they join or leave the network. Mailroom comes with a program that accomplishes this with minimum of effort on the part of the Network Administrator/Manager. There is also a program that allows the Network Administrator/Manager to install Mailroom on each user's workstation so that on execution of Mailroom the user's station may be identified and the configurations settings activated. It will create its own configuration and data/supporting files during the setup and installation process. The Mailroom program is written in Microsoft QuickBasic. It was developed to run on networked IBM XT/ATs or compatibles and requires that all participating workstations share a common drive. It has been implemented under DOS 3.2 and has a memory requirement of 71K. Mailroom was developed in 1988.

  16. Localizing and placement of network node functions in a network

    NARCIS (Netherlands)

    Strijkers, R.J.; Meulenhoff, P.J.

    2014-01-01

    The invention enables placement and use of a network node function in a second network node instead of using the network node function in a first network node. The network node function is e.g. a server function or a router function. The second network node is typically located in or close to the cl

  17. Localizing and placement of network node functions in a network

    NARCIS (Netherlands)

    Strijkers, R.J.; Meulenhoff, P.J.

    2014-01-01

    The invention enables placement and use of a network node function in a second network node instead of using the network node function in a first network node. The network node function is e.g. a server function or a router function. The second network node is typically located in or close to the

  18. Strategic performance management evaluation for the Navy's SPLICE local area networks

    OpenAIRE

    Blankenship, David D.

    1985-01-01

    Approved for public release; distribution is unlimited This thesis investigates those aspects of network performance evaluation thought to pertain specifically to strategic performance management evaluation of the Navy's Stock Point Logistics Integrated Communications Environment (SPLICE) local area networks at stock point and inventory control point sites- Background is provided concerning the SPLICE Project, strategic management, computer performance evaluation tools...

  19. Mathematical modeling of local perfusion in large distensible microvascular networks

    Science.gov (United States)

    Causin, Paola; Malgaroli, Francesca

    2017-08-01

    Microvessels -blood vessels with diameter less than 200 microns- form large, intricate networks organized into arterioles, capillaries and venules. In these networks, the distribution of flow and pressure drop is a highly interlaced function of single vessel resistances and mutual vessel interactions. In this paper we propose a mathematical and computational model to study the behavior of microcirculatory networks subjected to different conditions. The network geometry is composed of a graph of connected straight cylinders, each one representing a vessel. The blood flow and pressure drop across the single vessel, further split into smaller elements, are related through a generalized Ohm's law featuring a conductivity parameter, function of the vessel cross section area and geometry, which undergo deformations under pressure loads. The membrane theory is used to describe the deformation of vessel lumina, tailored to the structure of thick-walled arterioles and thin-walled venules. In addition, since venules can possibly experience negative transmural pressures, a buckling model is also included to represent vessel collapse. The complete model including arterioles, capillaries and venules represents a nonlinear system of PDEs, which is approached numerically by finite element discretization and linearization techniques. We use the model to simulate flow in the microcirculation of the human eye retina, a terminal system with a single inlet and outlet. After a phase of validation against experimental measurements, we simulate the network response to different interstitial pressure values. Such a study is carried out both for global and localized variations of the interstitial pressure. In both cases, significant redistributions of the blood flow in the network arise, highlighting the importance of considering the single vessel behavior along with its position and connectivity in the network.

  20. Fuzzy logic, neural networks, and soft computing

    Science.gov (United States)

    Zadeh, Lofti A.

    1994-01-01

    The past few years have witnessed a rapid growth of interest in a cluster of modes of modeling and computation which may be described collectively as soft computing. The distinguishing characteristic of soft computing is that its primary aims are to achieve tractability, robustness, low cost, and high MIQ (machine intelligence quotient) through an exploitation of the tolerance for imprecision and uncertainty. Thus, in soft computing what is usually sought is an approximate solution to a precisely formulated problem or, more typically, an approximate solution to an imprecisely formulated problem. A simple case in point is the problem of parking a car. Generally, humans can park a car rather easily because the final position of the car is not specified exactly. If it were specified to within, say, a few millimeters and a fraction of a degree, it would take hours or days of maneuvering and precise measurements of distance and angular position to solve the problem. What this simple example points to is the fact that, in general, high precision carries a high cost. The challenge, then, is to exploit the tolerance for imprecision by devising methods of computation which lead to an acceptable solution at low cost. By its nature, soft computing is much closer to human reasoning than the traditional modes of computation. At this juncture, the major components of soft computing are fuzzy logic (FL), neural network theory (NN), and probabilistic reasoning techniques (PR), including genetic algorithms, chaos theory, and part of learning theory. Increasingly, these techniques are used in combination to achieve significant improvement in performance and adaptability. Among the important application areas for soft computing are control systems, expert systems, data compression techniques, image processing, and decision support systems. It may be argued that it is soft computing, rather than the traditional hard computing, that should be viewed as the foundation for artificial

  1. Fuzzy logic, neural networks, and soft computing

    Science.gov (United States)

    Zadeh, Lofti A.

    1994-01-01

    The past few years have witnessed a rapid growth of interest in a cluster of modes of modeling and computation which may be described collectively as soft computing. The distinguishing characteristic of soft computing is that its primary aims are to achieve tractability, robustness, low cost, and high MIQ (machine intelligence quotient) through an exploitation of the tolerance for imprecision and uncertainty. Thus, in soft computing what is usually sought is an approximate solution to a precisely formulated problem or, more typically, an approximate solution to an imprecisely formulated problem. A simple case in point is the problem of parking a car. Generally, humans can park a car rather easily because the final position of the car is not specified exactly. If it were specified to within, say, a few millimeters and a fraction of a degree, it would take hours or days of maneuvering and precise measurements of distance and angular position to solve the problem. What this simple example points to is the fact that, in general, high precision carries a high cost. The challenge, then, is to exploit the tolerance for imprecision by devising methods of computation which lead to an acceptable solution at low cost. By its nature, soft computing is much closer to human reasoning than the traditional modes of computation. At this juncture, the major components of soft computing are fuzzy logic (FL), neural network theory (NN), and probabilistic reasoning techniques (PR), including genetic algorithms, chaos theory, and part of learning theory. Increasingly, these techniques are used in combination to achieve significant improvement in performance and adaptability. Among the important application areas for soft computing are control systems, expert systems, data compression techniques, image processing, and decision support systems. It may be argued that it is soft computing, rather than the traditional hard computing, that should be viewed as the foundation for artificial

  2. Spiking network simulation code for petascale computers

    Science.gov (United States)

    Kunkel, Susanne; Schmidt, Maximilian; Eppler, Jochen M.; Plesser, Hans E.; Masumoto, Gen; Igarashi, Jun; Ishii, Shin; Fukai, Tomoki; Morrison, Abigail; Diesmann, Markus; Helias, Moritz

    2014-01-01

    Brain-scale networks exhibit a breathtaking heterogeneity in the dynamical properties and parameters of their constituents. At cellular resolution, the entities of theory are neurons and synapses and over the past decade researchers have learned to manage the heterogeneity of neurons and synapses with efficient data structures. Already early parallel simulation codes stored synapses in a distributed fashion such that a synapse solely consumes memory on the compute node harboring the target neuron. As petaflop computers with some 100,000 nodes become increasingly available for neuroscience, new challenges arise for neuronal network simulation software: Each neuron contacts on the order of 10,000 other neurons and thus has targets only on a fraction of all compute nodes; furthermore, for any given source neuron, at most a single synapse is typically created on any compute node. From the viewpoint of an individual compute node, the heterogeneity in the synaptic target lists thus collapses along two dimensions: the dimension of the types of synapses and the dimension of the number of synapses of a given type. Here we present a data structure taking advantage of this double collapse using metaprogramming techniques. After introducing the relevant scaling scenario for brain-scale simulations, we quantitatively discuss the performance on two supercomputers. We show that the novel architecture scales to the largest petascale supercomputers available today. PMID:25346682

  3. Spiking network simulation code for petascale computers

    Directory of Open Access Journals (Sweden)

    Susanne eKunkel

    2014-10-01

    Full Text Available Brain-scale networks exhibit a breathtaking heterogeneity in the dynamical properties and parameters of their constituents. At cellular resolution, the entities of theory are neurons and synapses and over the past decade researchers have learned to manage the heterogeneity of neurons and synapses with efficient data structures. Already early parallel simulation codes stored synapses in a distributed fashion such that a synapse solely consumes memory on the compute node harboring the target neuron. As petaflop computers with some 100,000 nodes become increasingly available for neuroscience, new challenges arise for neuronal network simulation software: Each neuron contacts on the order of 10,000 other neurons and thus has targets only on a fraction of all compute nodes; furthermore, for any given source neuron, at most a single synapse is typically created on any compute node. From the viewpoint of an individual compute node, the heterogeneity in the synaptic target lists thus collapses along two dimensions: the dimension of the types of synapses and the dimension of the number of synapses of a given type. Here we present a data structure taking advantage of this double collapse using metaprogramming techniques. After introducing the relevant scaling scenario for brain-scale simulations, we quantitatively discuss the performance on two supercomputers. We show that the novel architecture scales to the largest petascale supercomputers available today.

  4. International Symposium on Complex Computing-Networks

    CERN Document Server

    Sevgi, L; CCN2005; Complex computing networks: Brain-like and wave-oriented electrodynamic algorithms

    2006-01-01

    This book uniquely combines new advances in the electromagnetic and the circuits&systems theory. It integrates both fields regarding computational aspects of common interest. Emphasized subjects are those methods which mimic brain-like and electrodynamic behaviour; among these are cellular neural networks, chaos and chaotic dynamics, attractor-based computation and stream ciphers. The book contains carefully selected contributions from the Symposium CCN2005. Pictures from the bestowal of Honorary Doctorate degrees to Leon O. Chua and Leopold B. Felsen are included.

  5. Quantum computation over the butterfly network

    CERN Document Server

    Kinjo, Yoshiyuki; Soeda, Akihito; Turner, Peter S

    2010-01-01

    In order to investigate distributed quantum computation under restricted network resources, we introduce a quantum computation task over the butterfly network where both quantum and classical communications are limited. We consider performing a two qubit global unitary operation on two unknown inputs given at different nodes, with outputs at two distinct nodes. By using a particular resource scenario introduced by Hayashi, which is capable of performing a swap operation by adding two maximally entangled qubits (ebits) between the two input nodes, we show that any controlled unitary operation can be performed without adding any entanglement resource. We also construct protocols for performing controlled traceless unitary operations with a 1-ebit resource and for performing global Clifford operations with a 2-ebit resource.

  6. Computational Methods for Modification of Metabolic Networks

    Directory of Open Access Journals (Sweden)

    Takeyuki Tamura

    2015-01-01

    Full Text Available In metabolic engineering, modification of metabolic networks is an important biotechnology and a challenging computational task. In the metabolic network modification, we should modify metabolic networks by newly adding enzymes or/and knocking-out genes to maximize the biomass production with minimum side-effect. In this mini-review, we briefly review constraint-based formalizations for Minimum Reaction Cut (MRC problem where the minimum set of reactions is deleted so that the target compound becomes non-producible from the view point of the flux balance analysis (FBA, elementary mode (EM, and Boolean models. Minimum Reaction Insertion (MRI problem where the minimum set of reactions is added so that the target compound newly becomes producible is also explained with a similar formalization approach. The relation between the accuracy of the models and the risk of overfitting is also discussed.

  7. An improved local immunization strategy for scale-free networks with a high degree of clustering

    Science.gov (United States)

    Xia, Lingling; Jiang, Guoping; Song, Yurong; Song, Bo

    2017-01-01

    The design of immunization strategies is an extremely important issue for disease or computer virus control and prevention. In this paper, we propose an improved local immunization strategy based on node's clustering which was seldom considered in the existing immunization strategies. The main aim of the proposed strategy is to iteratively immunize the node which has a high connectivity and a low clustering coefficient. To validate the effectiveness of our strategy, we compare it with two typical local immunization strategies on both real and artificial networks with a high degree of clustering. Simulations on these networks demonstrate that the performance of our strategy is superior to that of two typical strategies. The proposed strategy can be regarded as a compromise between computational complexity and immune effect, which can be widely applied in scale-free networks of high clustering, such as social network, technological networks and so on. In addition, this study provides useful hints for designing optimal immunization strategy for specific network.

  8. Computer networks. Citations from the NTIS data base

    Science.gov (United States)

    Jones, J. E.

    1980-08-01

    Research reports on aspects of computer networks, including hardware, software, data transmission, time sharing, and applicable theory to network design are cited. Specific studies on the ARPA networks, and other such systems are listed.

  9. The research of computer network security and protection strategy

    Science.gov (United States)

    He, Jian

    2017-05-01

    With the widespread popularity of computer network applications, its security is also received a high degree of attention. Factors affecting the safety of network is complex, for to do a good job of network security is a systematic work, has the high challenge. For safety and reliability problems of computer network system, this paper combined with practical work experience, from the threat of network security, security technology, network some Suggestions and measures for the system design principle, in order to make the masses of users in computer networks to enhance safety awareness and master certain network security technology.

  10. The Role of Marketing in Local Food Networks

    Directory of Open Access Journals (Sweden)

    Margrete Haugum

    2017-01-01

    Full Text Available Local food producers are often advised to collaborate with other local food producers to jointly participate in marketing and sales activities. Local food producers are often small and must operate many different activities to run their company, so the idea to collaborate may help them to become more efficient. We explore the role of marketing in local food networks through an analysis of marketing strategies and marketing mix in six local food networks in central Norway. When producers participate in food networks, they disconnect from direct relationships with their consumers. The value of this relationship must be considered in addition to costs related to sales and distribution in the network. The networks rely on regional products and regional branding as the main marketing strategy and promote local and localized products.

  11. Supporting localized activities in ubiquitous computing environments

    OpenAIRE

    Pinto, Helder

    2004-01-01

    The design of pervasive and ubiquitous computing systems must be centered on users' activity in order to bring computing systems closer to people. Adopting an activity-centered approach to the design of pervasive and ubiquitous computing systems leads us to seek to understand: a) how humans naturally accomplish an activity; and b) how computing artifacts from both the environmental and personal domains may contribute to the accomplishment of an activity. This work particularly focuses o...

  12. A new local-world evolving network model

    Institute of Scientific and Technical Information of China (English)

    Qin Sen; Dai Guan-Zhong

    2009-01-01

    In some real complex networks, only a few nodes can obtain the global information about the entire networks, but most of the nodes own only local connections therefore own only local information of the networks. A new local-world evolving network model is proposed in this paper. In the model, not all the nodes obtain local network information, which is different from the local world network model proposed by Li and Chen (LC model). In the LC model, each node has only the local connections therefore owns only local information about the entire networks. Theoretical analysis and numerical simulation show that adjusting the ratio of the number of nodes obtaining the global information of the network to the total number of nodes can effectively control the valuing range for the power-law exponent of the new network. Therefore, if the topological structure of a complex network, especially its exponent of power-law degree distribution, needs controlling, we just add or take away a few nodes which own the global information of the network.

  13. Computer network defense through radial wave functions

    Science.gov (United States)

    Malloy, Ian J.

    The purpose of this research is to synthesize basic and fundamental findings in quantum computing, as applied to the attack and defense of conventional computer networks. The concept focuses on uses of radio waves as a shield for, and attack against traditional computers. A logic bomb is analogous to a landmine in a computer network, and if one was to implement it as non-trivial mitigation, it will aid computer network defense. As has been seen in kinetic warfare, the use of landmines has been devastating to geopolitical regions in that they are severely difficult for a civilian to avoid triggering given the unknown position of a landmine. Thus, the importance of understanding a logic bomb is relevant and has corollaries to quantum mechanics as well. The research synthesizes quantum logic phase shifts in certain respects using the Dynamic Data Exchange protocol in software written for this work, as well as a C-NOT gate applied to a virtual quantum circuit environment by implementing a Quantum Fourier Transform. The research focus applies the principles of coherence and entanglement from quantum physics, the concept of expert systems in artificial intelligence, principles of prime number based cryptography with trapdoor functions, and modeling radio wave propagation against an event from unknown parameters. This comes as a program relying on the artificial intelligence concept of an expert system in conjunction with trigger events for a trapdoor function relying on infinite recursion, as well as system mechanics for elliptic curve cryptography along orbital angular momenta. Here trapdoor both denotes the form of cipher, as well as the implied relationship to logic bombs.

  14. Local rollback for fault-tolerance in parallel computing systems

    Science.gov (United States)

    Blumrich, Matthias A [Yorktown Heights, NY; Chen, Dong [Yorktown Heights, NY; Gara, Alan [Yorktown Heights, NY; Giampapa, Mark E [Yorktown Heights, NY; Heidelberger, Philip [Yorktown Heights, NY; Ohmacht, Martin [Yorktown Heights, NY; Steinmacher-Burow, Burkhard [Boeblingen, DE; Sugavanam, Krishnan [Yorktown Heights, NY

    2012-01-24

    A control logic device performs a local rollback in a parallel super computing system. The super computing system includes at least one cache memory device. The control logic device determines a local rollback interval. The control logic device runs at least one instruction in the local rollback interval. The control logic device evaluates whether an unrecoverable condition occurs while running the at least one instruction during the local rollback interval. The control logic device checks whether an error occurs during the local rollback. The control logic device restarts the local rollback interval if the error occurs and the unrecoverable condition does not occur during the local rollback interval.

  15. Considerations for a Shipboard Multilevel Secure Local Area Network

    Science.gov (United States)

    1992-03-01

    fulfillment of the requirements for the degree of MASTER OF SCIENCE IN TELECOMMUNICATIONS SYSTEMS MANAGEMENT from the NAVAL POSTGRADUATE SCHOOL March 1992...Intentions arc to merge the three separate networks into one network, the DISNET. Physicall % unprotected trunks and host access lines on the MILNET are being...Computer Security Press. April 19S2. 13. Computers at Risk: Safe Computing in the Information Ave. System Security Stud% Committee, Computer Science and

  16. Nanoarchitectonic atomic switch networks for unconventional computing

    Science.gov (United States)

    Demis, Eleanor C.; Aguilera, Renato; Scharnhorst, Kelsey; Aono, Masakazu; Stieg, Adam Z.; Gimzewski, James K.

    2016-11-01

    Developments in computing hardware are constrained by the operating principles of complementary metal oxide semiconductor (CMOS) technology, fabrication limits of nanometer scaled features, and difficulties in effective utilization of high density interconnects. This set of obstacles has promulgated a search for alternative, energy efficient approaches to computing inspired by natural systems including the mammalian brain. Atomic switch network (ASN) devices are a unique platform specifically developed to overcome these current barriers to realize adaptive neuromorphic technology. ASNs are composed of a massively interconnected network of atomic switches with a density of ∼109 units/cm2 and are structurally reminiscent of the neocortex of the brain. ASNs possess both the intrinsic capabilities of individual memristive switches, such as memory capacity and multi-state switching, and the characteristics of large-scale complex systems, such as power-law dynamics and non-linear transformations of input signals. Here we describe the successful nanoarchitectonic fabrication of next-generation ASN devices using combined top-down and bottom-up processing and experimentally demonstrate their utility as reservoir computing hardware. Leveraging their intrinsic dynamics and transformative input/output (I/O) behavior enabled waveform regression of periodic signals in the absence of embedded algorithms, further supporting the potential utility of ASN technology as a platform for unconventional approaches to computing.

  17. Computational fact checking from knowledge networks

    CERN Document Server

    Ciampaglia, Giovanni Luca; Rocha, Luis M; Bollen, Johan; Menczer, Filippo; Flammini, Alessandro

    2015-01-01

    Traditional fact checking by expert journalists cannot keep up with the enormous volume of information that is now generated online. Computational fact checking may significantly enhance our ability to evaluate the veracity of dubious information. Here we show that the complexities of human fact checking can be approximated quite well by finding the shortest path between concept nodes under properly defined semantic proximity metrics on knowledge graphs. Framed as a network problem this approach is feasible with efficient computational techniques. We evaluate this approach by examining tens of thousands of claims related to history, entertainment, geography, and biographical information using a public knowledge graph extracted from Wikipedia. Statements independently known to be true consistently receive higher support via our method than do false ones. These findings represent a significant step toward scalable computational fact-checking methods that may one day mitigate the spread of harmful misinformation...

  18. Epidemic spreading behavior in local-world evolving networks

    Institute of Scientific and Technical Information of China (English)

    Chengyi Xia; Zhongxin Liu; Zengqiang Chen; Shiwen Sun; Zhuzhi Yuan

    2008-01-01

    The susceptible-infected-susceptible (SIS) epidemic model is presented which can be used to study the epidemic spreading behavior in the local-world evolving network model. Local-world evolving model displays a transition from the exponential network to the scale-free network with respect to the connectivity distribution. From theoretical analyses and numerical simulations, we find that the epidemic spreading behavior on local-world networks also takes on some kind of transitional behaviors. The transitional behavior is further verified by comparing the spreading behavior of local-world network with that of random and scale-free networks. Some feasible control strategies are also proposed to keep from the epidemic spreading on networks.

  19. Local modularity for community detection in complex networks

    Science.gov (United States)

    Xiang, Ju; Hu, Tao; Zhang, Yan; Hu, Ke; Li, Jian-Ming; Xu, Xiao-Ke; Liu, Cui-Cui; Chen, Shi

    2016-02-01

    Community detection is a topic of interest in the study of complex networks such as the protein-protein interaction networks and metabolic networks. In recent years, various methods were proposed to detect community structures of the networks. Here, a kind of local modularity with tunable parameter is derived from the Newman-Girvan modularity by a special self-loop strategy that depends on the community division of the networks. By the self-loop strategy, one can easily control the definition of modularity, and the resulting modularity can be optimized by using the existing modularity optimization algorithms. The local modularity is used as the target function for community detection, and a self-consistent method is proposed for the optimization of the local modularity. We analyze the behaviors of the local modularity and show the validity of the local modularity in detecting community structures on various networks.

  20. Inequality measures perform differently in global and local assessments: An exploratory computational experiment

    Science.gov (United States)

    Chiang, Yen-Sheng

    2015-11-01

    Inequality measures are widely used in both the academia and public media to help us understand how incomes and wealth are distributed. They can be used to assess the distribution of a whole society-global inequality-as well as inequality of actors' referent networks-local inequality. How different is local inequality from global inequality? Formalizing the structure of reference groups as a network, the paper conducted a computational experiment to see how the structure of complex networks influences the difference between global and local inequality assessed by a selection of inequality measures. It was found that local inequality tends to be higher than global inequality when population size is large; network is dense and heterophilously assorted, and income distribution is less dispersed. The implications of the simulation findings are discussed.

  1. Target Localization Based on Improved DV-Hop Algorithm in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Xiaolong Huang

    2014-01-01

    Full Text Available The node localization technology of wireless sensor networks is essential and prerequisite to many applications, which it is one of the important support technologies for wireless sensor networks. The node localization is to get the position information of blind node by using location information of few known nodes and some special mechanisms. This paper primarily investigates a kind of target localization technology based on the improved DV-Hop algorithm in wireless sensor networks. We firstly compute the distances measured by RSSI and the mean value of one-hop distance. Then we can use the differences between the mean and the actual distance to get the error correction between the total distance and average one-hop distance. Replace trilateration with hybrid localization of MIN-MAX and weighted least square method. Finally, simulation experiment results show the improved algorithm can effectively carry out the network localization, thus has a certain of practical value

  2. Detectability and reliability analysis of the local seismic network in Pakistan

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The detectability and reliability analysis for the local seismic network is performed employing by Bungum and Husebye technique. The events were relocated using standard computer codes for hypocentral locations. The detectability levels are estimated from the twenty-five years of recorded data in terms of 50(, 90( and 100( cumulative detectability thresholds, which were derived from frequency-magnitude distribution. From this analysis the 100( level of detectability of the network is ML=1.7 for events which occur within the network. The accuracy in hypocentral solutions of the network is investigated by considering the fixed real hypocenter within the network. The epicentral errors are found to be less than 4 km when the events occur within the network. Finally, the problems faced during continuous operation of the local network, which effects its detectability, are discussed.

  3. EXTENDED MONTE CARLO LOCALIZATION ALGORITHM FOR MOBILE SENSOR NETWORKS

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A real-world localization system for wireless sensor networks that adapts for mobility and irregular radio propagation model is considered.The traditional range-based techniques and recent range-free localization schemes are not welt competent for localization in mobile sensor networks,while the probabilistic approach of Bayesian filtering with particle-based density representations provides a comprehensive solution to such localization problem.Monte Carlo localization is a Bayesian filtering method that approximates the mobile node’S location by a set of weighted particles.In this paper,an enhanced Monte Carlo localization algorithm-Extended Monte Carlo Localization (Ext-MCL) is suitable for the practical wireless network environment where the radio propagation model is irregular.Simulation results show the proposal gets better localization accuracy and higher localizable node number than previously proposed Monte Carlo localization schemes not only for ideal radio model,but also for irregular one.

  4. Competition between global and local online social networks.

    Science.gov (United States)

    Kleineberg, Kaj-Kolja; Boguñá, Marián

    2016-04-27

    The overwhelming success of online social networks, the key actors in the Web 2.0 cosmos, has reshaped human interactions globally. To help understand the fundamental mechanisms which determine the fate of online social networks at the system level, we describe the digital world as a complex ecosystem of interacting networks. In this paper, we study the impact of heterogeneity in network fitnesses on the competition between an international network, such as Facebook, and local services. The higher fitness of international networks is induced by their ability to attract users from all over the world, which can then establish social interactions without the limitations of local networks. In other words, inter-country social ties lead to increased fitness of the international network. To study the competition between an international network and local ones, we construct a 1:1000 scale model of the digital world, consisting of the 80 countries with the most Internet users. Under certain conditions, this leads to the extinction of local networks; whereas under different conditions, local networks can persist and even dominate completely. In particular, our model suggests that, with the parameters that best reproduce the empirical overtake of Facebook, this overtake could have not taken place with a significant probability.

  5. Competition between global and local online social networks

    Science.gov (United States)

    Kleineberg, Kaj-Kolja; Boguñá, Marián

    2016-04-01

    The overwhelming success of online social networks, the key actors in the Web 2.0 cosmos, has reshaped human interactions globally. To help understand the fundamental mechanisms which determine the fate of online social networks at the system level, we describe the digital world as a complex ecosystem of interacting networks. In this paper, we study the impact of heterogeneity in network fitnesses on the competition between an international network, such as Facebook, and local services. The higher fitness of international networks is induced by their ability to attract users from all over the world, which can then establish social interactions without the limitations of local networks. In other words, inter-country social ties lead to increased fitness of the international network. To study the competition between an international network and local ones, we construct a 1:1000 scale model of the digital world, consisting of the 80 countries with the most Internet users. Under certain conditions, this leads to the extinction of local networks; whereas under different conditions, local networks can persist and even dominate completely. In particular, our model suggests that, with the parameters that best reproduce the empirical overtake of Facebook, this overtake could have not taken place with a significant probability.

  6. State dependent computation using coupled recurrent networks

    CERN Document Server

    Rutishauser, Ueli

    2008-01-01

    Although conditional branching between possible behavioural states is a hallmark of intelligent behavior, very little is known about the neuronal mechanisms that support this processing. In a step toward solving this problem we demonstrate by theoretical analysis and simulation how networks of richly inter-connected neurons, such as those observed in the superficial layers of the neocortex, can embed reliable robust finite state machines. We show how a multi-stable neuronal network containing a number of states can be created very simply, by coupling two recurrent networks whose synaptic weights have been configured for soft winner-take-all (sWTA) performance. These two sWTAs have simple, homogenous locally recurrent connectivity except for a small fraction of recurrent cross-connections between them, which are used to embed the required states. This coupling between the maps allows the network to continue to express the current state even after the input that elicted that state is withdrawn. In addition, a s...

  7. An Application to WIN/ISIS Database on Local Network

    Directory of Open Access Journals (Sweden)

    Robert Lechien

    2005-07-01

    Full Text Available A Translated Article containing an application to how WIN/ISIS database work on local network. It starts with main definitions, and how to install WIN/ISIS on PC, and how to install it on the local network server.

  8. Synchronization in a Novel Local-World Dynamical Network Model

    Directory of Open Access Journals (Sweden)

    Jianeng Tang

    2014-01-01

    Full Text Available Advances in complex network research have recently stimulated increasing interests in understanding the relationship between the topology and dynamics of complex networks. In the paper, we study the synchronizability of a class of local-world dynamical networks. Then, we have proposed a local-world synchronization-optimal growth topology model. Compared with the local-world evolving network model, it exhibits a stronger synchronizability. We also investigate the robustness of the synchronizability with respect to random failures and the fragility of the synchronizability with specific removal of nodes.

  9. A localized coverage preserving protocol for wireless sensor networks.

    Science.gov (United States)

    Liu, Yuheng; Pu, Juhua; Zhang, Shuo; Liu, Yunlu; Xiong, Zhang

    2009-01-01

    In a randomly deployed and large scale wireless sensor network, coverage-redundant nodes consume much unnecessary energy. As a result, turning off these redundant nodes can prolong the network lifetime, while maintaining the degree of sensing coverage with a limited number of on-duty nodes. None of the off-duty eligibility rules in the literature, however, are sufficient and necessary conditions for eligible nodes. Hence redundancy or blind points might be incurred. In this paper we propose a complete Eligibility Rule based on Perimeter Coverage (ERPC) for a node to determine its eligibility for sleeping. ERPC has a computational complexity of O(N(2)log(N)), lower than the eligibility rule in the Coverage Control Protocol (CCP), O(N(3)), where N is the number of neighboring nodes. We then present a Coverage Preserving Protocol (CPP) to schedule the work state of eligible nodes. The main advantage of CPP over the Ottawa protocol lies in its ability to configure the network to any specific coverage degree, while the Ottawa protocol does not support different coverage configuration. Moreover, as a localized protocol, CPP has better adaptability to dynamic topologies than centralized protocols. Simulation results indicate that CPP can preserve network coverage with fewer active nodes than the Ottawa protocol. In addition, CPP is capable of identifying all the eligible nodes exactly while the CCP protocol might result in blind points due to error decisions. Quantitative analysis and experiments demonstrate that CPP can extend the network lifetime significantly while maintaining a given coverage degree.

  10. A Localized Coverage Preserving Protocol for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yuheng Liu

    2009-01-01

    Full Text Available In a randomly deployed and large scale wireless sensor network, coverage-redundant nodes consume much unnecessary energy. As a result, turning off these redundant nodes can prolong the network lifetime, while maintaining the degree of sensing coverage with a limited number of on-duty nodes. None of the off-duty eligibility rules in the literature, however, are sufficient and necessary conditions for eligible nodes. Hence redundancy or blind points might be incurred. In this paper we propose a complete Eligibility Rule based on Perimeter Coverage (ERPC for a node to determine its eligibility for sleeping. ERPC has a computational complexity of O(N2log(N, lower than the eligibility rule in the Coverage Control Protocol (CCP, O(N3, where N is the number of neighboring nodes. We then present a Coverage Preserving Protocol (CPP to schedule the work state of eligible nodes. The main advantage of CPP over the Ottawa protocol lies in its ability to configure the network to any specific coverage degree, while the Ottawa protocol does not support different coverage configuration. Moreover, as a localized protocol, CPP has better adaptability to dynamic topologies than centralized protocols. Simulation results indicate that CPP can preserve network coverage with fewer active nodes than the Ottawa protocol. In addition, CPP is capable of identifying all the eligible nodes exactly while the CCP protocol might result in blind points due to error decisions. Quantitative analysis and experiments demonstrate that CPP can extend the network lifetime significantly while maintaining a given coverage degree.

  11. Local Area Networks: Vehicles for Connecting and Sharing Information.

    Science.gov (United States)

    Lipman, Art

    1993-01-01

    Describes local area networks (LANs) and discusses advantages of their use in schools for students and teachers, including networking in labs, media centers, and classrooms. Roles of the network supervisor and/or technician are explained, including making decisions about the rights of users and instruction and assistance. (LRW)

  12. Fibre Optics In A Multi-Star Wideband Local Network

    Science.gov (United States)

    Fox, J. R.

    1983-08-01

    Early experience has been gained with the switched-star type of network in the Fibrevision cable TV trial at Milton Keynes, and British Telecom are progressing towards a full-scale multi-star wideband local network. This paper discusses both the present and future use of fibre optics in this type of network.

  13. Optimal operation of water distribution networks under local pipe failures

    Institute of Scientific and Technical Information of China (English)

    TIAN Yi-mei; G.Y.FU; CHI Hai-yan; LIU Ye

    2007-01-01

    The optimal operation of water distribution networks under local pipe failures, such as water main breaks, was proposed.Based on a hydraulic analysis and a simulation of water distribution networks, a macroscopic model for a network under a local pipe failure was established by the statistical regression. After the operation objectives under a local pipe failure were determined, the optimal operation model was developed and solved by the genetic algorithm. The program was developed and examined by a city distribution network. The optimal operation alternative shows that the electricity cost is saved approximately 11%, the income of the water corporation is increased approximately 5%, and the pressure in the water distribution network is distributed evenly to ensure the network safe operation. Therefore, the proposed method for optimal operation under local pipe failure is feasible and cost-effective.

  14. Computer network security and cyber ethics

    CERN Document Server

    Kizza, Joseph Migga

    2014-01-01

    In its 4th edition, this book remains focused on increasing public awareness of the nature and motives of cyber vandalism and cybercriminals, the weaknesses inherent in cyberspace infrastructure, and the means available to protect ourselves and our society. This new edition aims to integrate security education and awareness with discussions of morality and ethics. The reader will gain an understanding of how the security of information in general and of computer networks in particular, on which our national critical infrastructure and, indeed, our lives depend, is based squarely on the individ

  15. Social sciences via network analysis and computation

    CERN Document Server

    Kanduc, Tadej

    2015-01-01

    In recent years information and communication technologies have gained significant importance in the social sciences. Because there is such rapid growth of knowledge, methods and computer infrastructure, research can now seamlessly connect interdisciplinary fields such as business process management, data processing and mathematics. This study presents some of the latest results, practices and state-of-the-art approaches in network analysis, machine learning, data mining, data clustering and classifications in the contents of social sciences. It also covers various real-life examples such as t

  16. Effective information spreading based on local information in correlated networks

    Science.gov (United States)

    Gao, Lei; Wang, Wei; Pan, Liming; Tang, Ming; Zhang, Hai-Feng

    2016-12-01

    Using network-based information to facilitate information spreading is an essential task for spreading dynamics in complex networks. Focusing on degree correlated networks, we propose a preferential contact strategy based on the local network structure and local informed density to promote the information spreading. During the spreading process, an informed node will preferentially select a contact target among its neighbors, basing on their degrees or local informed densities. By extensively implementing numerical simulations in synthetic and empirical networks, we find that when only consider the local structure information, the convergence time of information spreading will be remarkably reduced if low-degree neighbors are favored as contact targets. Meanwhile, the minimum convergence time depends non-monotonically on degree-degree correlation, and a moderate correlation coefficient results in the most efficient information spreading. Incorporating the local informed density information into contact strategy, the convergence time of information spreading can be further reduced, and be minimized by an moderately preferential selection.

  17. WEB BASED LEARNING OF COMPUTER NETWORK COURSE

    Directory of Open Access Journals (Sweden)

    Hakan KAPTAN

    2004-04-01

    Full Text Available As a result of developing on Internet and computer fields, web based education becomes one of the area that many improving and research studies are done. In this study, web based education materials have been explained for multimedia animation and simulation aided Computer Networks course in Technical Education Faculties. Course content is formed by use of university course books, web based education materials and technology web pages of companies. Course content is formed by texts, pictures and figures to increase motivation of students and facilities of learning some topics are supported by animations. Furthermore to help working principles of routing algorithms and congestion control algorithms simulators are constructed in order to interactive learning

  18. Effects of local and global network connectivity on synergistic epidemics

    CERN Document Server

    Broder-Rodgers, David; Taraskin, Sergei N

    2015-01-01

    The effects of local and global connectivity on the spread of synergistic susceptible-infected-removed epidemics were studied in lattice models with infinite- and finite-range rewiring (small-world and small-world-like models). Several effects were found numerically and supported analytically within a simple model: (i) rewiring enhanced resilience to epidemics with strong constructive synergy on networks with high local connectivity; (ii) rewiring enhanced spread of epidemics with destructive or weak constructive synergy on networks with arbitrary local connectivity; (iii) rewiring enhanced spread of epidemics, independent of synergy, in networks with low local connectivity.

  19. Real-time network traffic classification technique for wireless local area networks based on compressed sensing

    Science.gov (United States)

    Balouchestani, Mohammadreza

    2017-05-01

    Network traffic or data traffic in a Wireless Local Area Network (WLAN) is the amount of network packets moving across a wireless network from each wireless node to another wireless node, which provide the load of sampling in a wireless network. WLAN's Network traffic is the main component for network traffic measurement, network traffic control and simulation. Traffic classification technique is an essential tool for improving the Quality of Service (QoS) in different wireless networks in the complex applications such as local area networks, wireless local area networks, wireless personal area networks, wireless metropolitan area networks, and wide area networks. Network traffic classification is also an essential component in the products for QoS control in different wireless network systems and applications. Classifying network traffic in a WLAN allows to see what kinds of traffic we have in each part of the network, organize the various kinds of network traffic in each path into different classes in each path, and generate network traffic matrix in order to Identify and organize network traffic which is an important key for improving the QoS feature. To achieve effective network traffic classification, Real-time Network Traffic Classification (RNTC) algorithm for WLANs based on Compressed Sensing (CS) is presented in this paper. The fundamental goal of this algorithm is to solve difficult wireless network management problems. The proposed architecture allows reducing False Detection Rate (FDR) to 25% and Packet Delay (PD) to 15 %. The proposed architecture is also increased 10 % accuracy of wireless transmission, which provides a good background for establishing high quality wireless local area networks.

  20. Scalable and Fully Distributed Localization in Large-Scale Sensor Networks

    Directory of Open Access Journals (Sweden)

    Miao Jin

    2017-06-01

    Full Text Available This work proposes a novel connectivity-based localization algorithm, well suitable for large-scale sensor networks with complex shapes and a non-uniform nodal distribution. In contrast to current state-of-the-art connectivity-based localization methods, the proposed algorithm is highly scalable with linear computation and communication costs with respect to the size of the network; and fully distributed where each node only needs the information of its neighbors without cumbersome partitioning and merging process. The algorithm is theoretically guaranteed and numerically stable. Moreover, the algorithm can be readily extended to the localization of networks with a one-hop transmission range distance measurement, and the propagation of the measurement error at one sensor node is limited within a small area of the network around the node. Extensive simulations and comparison with other methods under various representative network settings are carried out, showing the superior performance of the proposed algorithm.

  1. A complex network approach to cloud computing

    CERN Document Server

    Travieso, Gonzalo; Bruno, Odemir Martinez; Costa, Luciano da Fontoura

    2015-01-01

    Cloud computing has become an important means to speed up computing. One problem influencing heavily the performance of such systems is the choice of nodes as servers responsible for executing the users' tasks. In this article we report how complex networks can be used to model such a problem. More specifically, we investigate the performance of the processing respectively to cloud systems underlain by Erdos-Renyi and Barabasi-Albert topology containing two servers. Cloud networks involving two communities not necessarily of the same size are also considered in our analysis. The performance of each configuration is quantified in terms of two indices: the cost of communication between the user and the nearest server, and the balance of the distribution of tasks between the two servers. Regarding the latter index, the ER topology provides better performance than the BA case for smaller average degrees and opposite behavior for larger average degrees. With respect to the cost, smaller values are found in the BA ...

  2. A Packet Routing Model for Computer Networks

    Directory of Open Access Journals (Sweden)

    O. Osunade

    2012-05-01

    Full Text Available The quest for reliable data transmission in today’s computer networks and internetworks forms the basis for which routing schemes need be improved upon. The persistent increase in the size of internetwork leads to a dwindling performance of the present routing algorithms which are meant to provide optimal path for forwarding packets from one network to the other. A mathematical and analytical routing model framework is proposed to address the routing needs to a substantial extent. The model provides schemes typical of packet sources, queuing system within a buffer, links and bandwidth allocation and time-based bandwidth generator in routing chunks of packets to their destinations. Principal to the choice of link are such design considerations as least-congested link in a set of links, normalized throughput, mean delay and mean waiting time and the priority of packets in a set of prioritized packets. These performance metrics were targeted and the resultant outcome is a fair, load-balanced network.

  3. Visualization techniques for computer network defense

    Science.gov (United States)

    Beaver, Justin M.; Steed, Chad A.; Patton, Robert M.; Cui, Xiaohui; Schultz, Matthew

    2011-06-01

    Effective visual analysis of computer network defense (CND) information is challenging due to the volume and complexity of both the raw and analyzed network data. A typical CND is comprised of multiple niche intrusion detection tools, each of which performs network data analysis and produces a unique alerting output. The state-of-the-practice in the situational awareness of CND data is the prevalent use of custom-developed scripts by Information Technology (IT) professionals to retrieve, organize, and understand potential threat events. We propose a new visual analytics framework, called the Oak Ridge Cyber Analytics (ORCA) system, for CND data that allows an operator to interact with all detection tool outputs simultaneously. Aggregated alert events are presented in multiple coordinated views with timeline, cluster, and swarm model analysis displays. These displays are complemented with both supervised and semi-supervised machine learning classifiers. The intent of the visual analytics framework is to improve CND situational awareness, to enable an analyst to quickly navigate and analyze thousands of detected events, and to combine sophisticated data analysis techniques with interactive visualization such that patterns of anomalous activities may be more easily identified and investigated.

  4. Visualization Techniques for Computer Network Defense

    Energy Technology Data Exchange (ETDEWEB)

    Beaver, Justin M [ORNL; Steed, Chad A [ORNL; Patton, Robert M [ORNL; Cui, Xiaohui [ORNL; Schultz, Matthew A [ORNL

    2011-01-01

    Effective visual analysis of computer network defense (CND) information is challenging due to the volume and complexity of both the raw and analyzed network data. A typical CND is comprised of multiple niche intrusion detection tools, each of which performs network data analysis and produces a unique alerting output. The state-of-the-practice in the situational awareness of CND data is the prevalent use of custom-developed scripts by Information Technology (IT) professionals to retrieve, organize, and understand potential threat events. We propose a new visual analytics framework, called the Oak Ridge Cyber Analytics (ORCA) system, for CND data that allows an operator to interact with all detection tool outputs simultaneously. Aggregated alert events are presented in multiple coordinated views with timeline, cluster, and swarm model analysis displays. These displays are complemented with both supervised and semi-supervised machine learning classifiers. The intent of the visual analytics framework is to improve CND situational awareness, to enable an analyst to quickly navigate and analyze thousands of detected events, and to combine sophisticated data analysis techniques with interactive visualization such that patterns of anomalous activities may be more easily identified and investigated.

  5. Local control of cognitive radio networks

    NARCIS (Netherlands)

    Doerr, C.; Grunwald, D.; Sicker, D.C.

    2009-01-01

    In a network deployment, a cognitive radio will have to perform two fundamental tasks. First, each cognitive radio needs to optimize its internal operation, and second, it needs to derive a configuration that will enable and optimize communication with other nodes in the network. This latter require

  6. Some Issues on Computer Networks: Architecture and Key Technologies

    Institute of Scientific and Technical Information of China (English)

    Guan-Qun Gu; Jun-Zhou Luo

    2006-01-01

    The evolution of computer networks has experienced several major steps, and research focus of each step has been kept changing and evolving, from ARPANET to OSI/RM, then HSN (high speed network) and HPN (high performance network). During the evolution, computer networks represented by Internet have made great progress and gained unprecedented success. However, with the appearance and intensification of tussle, along with the three difficult problems (service customizing, resource control and user management) of modern network, it is found that traditional Internet and its architecture no longer meet the requirements of next generation network. Therefore, it is the next generation network that current Internet must evolve to. With the mindset of achieving valuable guidance for research on next generation network, this paper firstly analyzes some dilemmas facing current Internet and its architecture, and then surveys some recent influential research work and progresses in computer networks and related areas, including new generation network architecture, network resource control technologies, network management and security, distributed computing and middleware,wireless/mobile network, new generation network services and applications, and foundational theories on network modeling.Finally, this paper concludes that within the research on next generation network, more attention should be paid to the high availability network and corresponding architecture, key theories and supporting technologies.

  7. Localization Algorithm Based on a Spring Model (LASM for Large Scale Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Shuai Li

    2008-03-01

    Full Text Available A navigation method for a lunar rover based on large scale wireless sensornetworks is proposed. To obtain high navigation accuracy and large exploration area, highnode localization accuracy and large network scale are required. However, thecomputational and communication complexity and time consumption are greatly increasedwith the increase of the network scales. A localization algorithm based on a spring model(LASM method is proposed to reduce the computational complexity, while maintainingthe localization accuracy in large scale sensor networks. The algorithm simulates thedynamics of physical spring system to estimate the positions of nodes. The sensor nodesare set as particles with masses and connected with neighbor nodes by virtual springs. Thevirtual springs will force the particles move to the original positions, the node positionscorrespondingly, from the randomly set positions. Therefore, a blind node position can bedetermined from the LASM algorithm by calculating the related forces with the neighbornodes. The computational and communication complexity are O(1 for each node, since thenumber of the neighbor nodes does not increase proportionally with the network scale size.Three patches are proposed to avoid local optimization, kick out bad nodes and deal withnode variation. Simulation results show that the computational and communicationcomplexity are almost constant despite of the increase of the network scale size. The time consumption has also been proven to remain almost constant since the calculation steps arealmost unrelated with the network scale size.

  8. The Impact of Metagovernance on Local Governance Networks

    DEFF Research Database (Denmark)

    Damgaard, Bodil; Torfing, Jacob

    2011-01-01

    This article analyses the impact of metagovernance on the functioning of local governance networks. It does so by comparing the functioning of four local governance networks in the field of local employment policy in Denmark. Between 2007 and 2009, two of these networks were linked to jobcentres...... in which the municipality and a state agency shared responsibility for employment policy, while the other two were linked to jobcentres in which the municipality had full responsibility. We explore two types of metagovernance that the local governance networks were subject to: general, hands......-off metagovernance consisting of the assignment of full responsibility to the municipality alone, or of shared responsibility to the municipality and the state jointly; and tailored and fine-tuned metagovernance directed towards only one or a few networks and their corresponding jobcentre(s). Our findings suggest...

  9. Local Optima Networks of the Quadratic Assignment Problem

    CERN Document Server

    Daolio, Fabio; Ochoa, Gabriela; Tomassini, Marco

    2011-01-01

    Using a recently proposed model for combinatorial landscapes, Local Optima Networks (LON), we conduct a thorough analysis of two types of instances of the Quadratic Assignment Problem (QAP). This network model is a reduction of the landscape in which the nodes correspond to the local optima, and the edges account for the notion of adjacency between their basins of attraction. The model was inspired by the notion of 'inherent network' of potential energy surfaces proposed in physical-chemistry. The local optima networks extracted from the so called uniform and real-like QAP instances, show features clearly distinguishing these two types of instances. Apart from a clear confirmation that the search difficulty increases with the problem dimension, the analysis provides new confirming evidence explaining why the real-like instances are easier to solve exactly using heuristic search, while the uniform instances are easier to solve approximately. Although the local optima network model is still under development, w...

  10. Effective information spreading based on local information in correlated networks

    CERN Document Server

    Gao, Lei; Pan, Liming; Tang, Ming; Zhang, Hai-Feng

    2016-01-01

    Using network-based information to facilitate information spreading is an essential task for spreading dynamics in complex networks, which will benefit the promotion of technical innovations, healthy behaviors, new products, etc. Focusing on degree correlated networks, we propose a preferential contact strategy based on the local network structure and local informed density to promote the information spreading. During the spreading process, an informed node will preferentially select a contact target among its neighbors, basing on their degrees or local informed densities. By extensively implementing numerical simulations in synthetic and empirical networks, we find that when only consider the local structure information, the convergence time of information spreading will be remarkably reduced if low-degree neighbors are favored as contact targets. Meanwhile, the minimum convergence time depends non-monotonically on degree-degree correlation, and moderate correlation coefficients result in most efficient info...

  11. Chemical Reaction Networks for Computing Polynomials.

    Science.gov (United States)

    Salehi, Sayed Ahmad; Parhi, Keshab K; Riedel, Marc D

    2017-01-20

    Chemical reaction networks (CRNs) provide a fundamental model in the study of molecular systems. Widely used as formalism for the analysis of chemical and biochemical systems, CRNs have received renewed attention as a model for molecular computation. This paper demonstrates that, with a new encoding, CRNs can compute any set of polynomial functions subject only to the limitation that these functions must map the unit interval to itself. These polynomials can be expressed as linear combinations of Bernstein basis polynomials with positive coefficients less than or equal to 1. In the proposed encoding approach, each variable is represented using two molecular types: a type-0 and a type-1. The value is the ratio of the concentration of type-1 molecules to the sum of the concentrations of type-0 and type-1 molecules. The proposed encoding naturally exploits the expansion of a power-form polynomial into a Bernstein polynomial. Molecular encoders for converting any input in a standard representation to the fractional representation as well as decoders for converting the computed output from the fractional to a standard representation are presented. The method is illustrated first for generic CRNs; then chemical reactions designed for an example are mapped to DNA strand-displacement reactions.

  12. Intrinsic excitability state of local neuronal population modulates signal propagation in feed-forward neural networks.

    Science.gov (United States)

    Han, Ruixue; Wang, Jiang; Yu, Haitao; Deng, Bin; Wei, Xilei; Qin, Yingmei; Wang, Haixu

    2015-04-01

    Reliable signal propagation across distributed brain areas is an essential requirement for cognitive function, and it has been investigated extensively in computational studies where feed-forward network (FFN) is taken as a generic model. But it is still unclear how distinct local network states, which are intrinsically generated by synaptic interactions within each layer, would affect the ability of FFN to transmit information. Here we investigate the impact of such network states on propagating transient synchrony (synfire) and firing rate by a combination of numerical simulations and analytical approach. Specifically, local network dynamics is attributed to the competition between excitatory and inhibitory neurons within each layer. Our results show that concomitant with different local network states, the performance of signal propagation differs dramatically. For both synfire propagation and firing rate propagation, there exists an optimal local excitability state, respectively, that optimizes the performance of signal propagation. Furthermore, we find that long-range connections strongly change the dependence of spiking activity propagation on local network state and propose that these two factors work jointly to determine information transmission across distributed networks. Finally, a simple mean field approach that bridges response properties of long-range connectivity and local subnetworks is utilized to reveal the underlying mechanism.

  13. The Service Concept Applied to Computer Networks. Technical Note 880.

    Science.gov (United States)

    Abrams, Marshall D.; Cotton, Ira W.

    The Network Measurement System (NMS) represents the implementation of a new approach to the performance measurement and evaluation of computer network systems and services. By focusing on the service delivered to network customers at their terminals, rather than on the internal mechanics of network operation, measurements can be obtained which are…

  14. Computation of loss allocation in electric power networks using loss ...

    African Journals Online (AJOL)

    Computation of loss allocation in electric power networks using loss vector. ... The losses to be allocated are derived from load flow of a specified power network and operating conditions. Loss vectors associated with demand ... Article Metrics.

  15. Network and computing infrastructure for scientific applications in Georgia

    Science.gov (United States)

    Kvatadze, R.; Modebadze, Z.

    2016-09-01

    Status of network and computing infrastructure and available services for research and education community of Georgia are presented. Research and Educational Networking Association - GRENA provides the following network services: Internet connectivity, network services, cyber security, technical support, etc. Computing resources used by the research teams are located at GRENA and at major state universities. GE-01-GRENA site is included in European Grid infrastructure. Paper also contains information about programs of Learning Center and research and development projects in which GRENA is participating.

  16. 2013 International Conference on Computer Engineering and Network

    CERN Document Server

    Zhu, Tingshao

    2014-01-01

    This book aims to examine innovation in the fields of computer engineering and networking. The book covers important emerging topics in computer engineering and networking, and it will help researchers and engineers improve their knowledge of state-of-art in related areas. The book presents papers from The Proceedings of the 2013 International Conference on Computer Engineering and Network (CENet2013) which was held on July 20-21, in Shanghai, China.

  17. Mechanisms of protection of information in computer networks and systems

    Directory of Open Access Journals (Sweden)

    Sergey Petrovich Evseev

    2011-10-01

    Full Text Available Protocols of information protection in computer networks and systems are investigated. The basic types of threats of infringement of the protection arising from the use of computer networks are classified. The basic mechanisms, services and variants of realization of cryptosystems for maintaining authentication, integrity and confidentiality of transmitted information are examined. Their advantages and drawbacks are described. Perspective directions of development of cryptographic transformations for the maintenance of information protection in computer networks and systems are defined and analyzed.

  18. High Performance Networks From Supercomputing to Cloud Computing

    CERN Document Server

    Abts, Dennis

    2011-01-01

    Datacenter networks provide the communication substrate for large parallel computer systems that form the ecosystem for high performance computing (HPC) systems and modern Internet applications. The design of new datacenter networks is motivated by an array of applications ranging from communication intensive climatology, complex material simulations and molecular dynamics to such Internet applications as Web search, language translation, collaborative Internet applications, streaming video and voice-over-IP. For both Supercomputing and Cloud Computing the network enables distributed applicati

  19. Classification and Analysis of Computer Network Traffic

    DEFF Research Database (Denmark)

    Bujlow, Tomasz

    2014-01-01

    various classification modes (decision trees, rulesets, boosting, softening thresholds) regarding the classification accuracy and the time required to create the classifier. We showed how to use our VBS tool to obtain per-flow, per-application, and per-content statistics of traffic in computer networks...... classification (as by using transport layer port numbers, Deep Packet Inspection (DPI), statistical classification) and assessed their usefulness in particular areas. We found that the classification techniques based on port numbers are not accurate anymore as most applications use dynamic port numbers, while...... DPI is relatively slow, requires a lot of processing power, and causes a lot of privacy concerns. Statistical classifiers based on Machine Learning Algorithms (MLAs) were shown to be fast and accurate. At the same time, they do not consume a lot of resources and do not cause privacy concerns. However...

  20. Locality-Driven Parallel Static Analysis for Power Delivery Networks

    KAUST Repository

    Zeng, Zhiyu

    2011-06-01

    Large VLSI on-chip Power Delivery Networks (PDNs) are challenging to analyze due to the sheer network complexity. In this article, a novel parallel partitioning-based PDN analysis approach is presented. We use the boundary circuit responses of each partition to divide the full grid simulation problem into a set of independent subgrid simulation problems. Instead of solving exact boundary circuit responses, a more efficient scheme is proposed to provide near-exact approximation to the boundary circuit responses by exploiting the spatial locality of the flip-chip-type power grids. This scheme is also used in a block-based iterative error reduction process to achieve fast convergence. Detailed computational cost analysis and performance modeling is carried out to determine the optimal (or near-optimal) number of partitions for parallel implementation. Through the analysis of several large power grids, the proposed approach is shown to have excellent parallel efficiency, fast convergence, and favorable scalability. Our approach can solve a 16-million-node power grid in 18 seconds on an IBM p5-575 processing node with 16 Power5+ processors, which is 18.8X faster than a state-of-the-art direct solver. © 2011 ACM.

  1. Model-based Leakage Localization in Drinking Water Distribution Networks using Structured Residuals

    OpenAIRE

    Rosich, Albert; Puig, Vicenç

    2013-01-01

    In this paper, a new model based approach to leakage localization in drinking water networks is proposed based on generating a set of structured residuals. The residual evaluation is based on a numerical method based on an enhanced Newton-Raphson algorithm. The proposed method is suitable for water network systems because the non-linearities of the model make impossible to derive analytical residuals. Furthermore, the computed residuals are designed so that leaks are decoupled, which impro...

  2. Localization in smart dust sensor networks

    NARCIS (Netherlands)

    Kilic, Y.; Meijerink, Arjan; Bentum, Marinus Jan

    2010-01-01

    Our research goal is to design a robust localization system that offers good accuracy even in the harsh indoor and outdoor environments by handling problems in the physical layer. In this respect, localization based on ultra-wide band (UWB) technology with time-based ranging is a good candidate

  3. AUTOMATIC CONTROL OF INTELLECTUAL RIGHTS IN THE GLOBAL COMPUTER NETWORKS

    Directory of Open Access Journals (Sweden)

    Anatoly P. Yakimaho

    2013-01-01

    Full Text Available The problems of use of subjects of intellectual property in the global computer networks are stated. The main attention is focused on the ways of problems solutions arising during the work in computer networks. Legal problems of information society are considered. The analysis of global computer networks as places for the organization of collective management by copyrights in the world scale is carried out. Issues of creation of a system of automatic control of property rights of authors and owners in the global computer networks are taken up.

  4. ARACHNE: A neural-neuroglial network builder with remotely controlled parallel computing.

    Science.gov (United States)

    Aleksin, Sergey G; Zheng, Kaiyu; Rusakov, Dmitri A; Savtchenko, Leonid P

    2017-03-31

    Creating and running realistic models of neural networks has hitherto been a task for computing professionals rather than experimental neuroscientists. This is mainly because such networks usually engage substantial computational resources, the handling of which requires specific programing skills. Here we put forward a newly developed simulation environment ARACHNE: it enables an investigator to build and explore cellular networks of arbitrary biophysical and architectural complexity using the logic of NEURON and a simple interface on a local computer or a mobile device. The interface can control, through the internet, an optimized computational kernel installed on a remote computer cluster. ARACHNE can combine neuronal (wired) and astroglial (extracellular volume-transmission driven) network types and adopt realistic cell models from the NEURON library. The program and documentation (current version) are available at GitHub repository https://github.com/LeonidSavtchenko/Arachne under the MIT License (MIT).

  5. Learning Local Components to Understand Large Bayesian Networks

    DEFF Research Database (Denmark)

    Zeng, Yifeng; Xiang, Yanping; Cordero, Jorge

    2009-01-01

    Bayesian networks are known for providing an intuitive and compact representation of probabilistic information and allowing the creation of models over a large and complex domain. Bayesian learning and reasoning are nontrivial for a large Bayesian network. In parallel, it is a tough job for users...... (domain experts) to extract accurate information from a large Bayesian network due to dimensional difficulty. We define a formulation of local components and propose a clustering algorithm to learn such local components given complete data. The algorithm groups together most inter-relevant attributes...... in a domain. We evaluate its performance on three benchmark Bayesian networks and provide results in support. We further show that the learned components may represent local knowledge more precisely in comparison to the full Bayesian networks when working with a small amount of data....

  6. Green Computing in Local Governments and Information Technology Companies

    Directory of Open Access Journals (Sweden)

    Badar Agung Nugroho

    2013-06-01

    Full Text Available Green computing is a study and practice of designing, manufacturing, using, and disposing of information and communication devices efficiently and effectively with minimum impact on the environment. If the green computing concept was implemented, it will help the agencies or companies to reduce energy and capital cost from their IT infrastructure. The goal from this research is to explore the current condition about the efforts from local governments and IT companies at West Java to implement the green computing concept at their working environment. The primary data were collected by using focus group discussion by inviting the local governments and IT companies representatives who responsible to manage their IT infrastructure. And then, the secondary data were collected by doing brief observation in order to see the real effort of green computing implementation at each institution. The result shows that there are many different perspectives and efforts of green computing implementation between local governments and IT companies.

  7. The Semi-Planned LAN: Prototyping a Local Area Network.

    Science.gov (United States)

    True, John F.; Rosenwald, Judah

    1986-01-01

    Five administrative user departments at San Francisco State University discovered that they had common requirements for office automation and data manipulation that could be addressed with microcomputers. The results of a local area network project are presented. (Author/MLW)

  8. Cluster-based localization and tracking in ubiquitous computing systems

    CERN Document Server

    Martínez-de Dios, José Ramiro; Torres-González, Arturo; Ollero, Anibal

    2017-01-01

    Localization and tracking are key functionalities in ubiquitous computing systems and techniques. In recent years a very high variety of approaches, sensors and techniques for indoor and GPS-denied environments have been developed. This book briefly summarizes the current state of the art in localization and tracking in ubiquitous computing systems focusing on cluster-based schemes. Additionally, existing techniques for measurement integration, node inclusion/exclusion and cluster head selection are also described in this book.

  9. 3Com Etherseries Local Area Network

    Science.gov (United States)

    1989-03-01

    have mail waiting for them the next time they log on the network. Also, the server will notify the sender if the message is undeliverable. Networks with...drive E: contains the volume INBOX which is used as the mailbox on the server to store electronic mail . EtherShare volumes can have three kinds of...numerical order received mail in your INBOX volume. If there is no mail the screen will be blank. Immediately upon starting EMAIL the program will check to

  10. Comparing Local Descriptors and Bags of Visual Words to Deep Convolutional Neural Networks for Plant Recognition

    NARCIS (Netherlands)

    Pawara, Pornntiwa; Okafor, Emmanuel; Surinta, Olarik; Schomaker, Lambertus; Wiering, Marco

    2017-01-01

    The use of machine learning and computer vision methods for recognizing different plants from images has attracted lots of attention from the community. This paper aims at comparing local feature descriptors and bags of visual words with different classifiers to deep convolutional neural networks (C

  11. Email networks and the spread of computer viruses

    Science.gov (United States)

    Newman, M. E.; Forrest, Stephanie; Balthrop, Justin

    2002-09-01

    Many computer viruses spread via electronic mail, making use of computer users' email address books as a source for email addresses of new victims. These address books form a directed social network of connections between individuals over which the virus spreads. Here we investigate empirically the structure of this network using data drawn from a large computer installation, and discuss the implications of this structure for the understanding and prevention of computer virus epidemics.

  12. Makeup like a superstar: Deep Localized Makeup Transfer Network

    OpenAIRE

    Liu, Si; Ou, Xinyu; Qian, Ruihe; Wang, Wei; Cao, Xiaochun

    2016-01-01

    In this paper, we propose a novel Deep Localized Makeup Transfer Network to automatically recommend the most suitable makeup for a female and synthesis the makeup on her face. Given a before-makeup face, her most suitable makeup is determined automatically. Then, both the beforemakeup and the reference faces are fed into the proposed Deep Transfer Network to generate the after-makeup face. Our end-to-end makeup transfer network have several nice properties including: (1) with complete functio...

  13. Wireless Local Area Networks: The Next Evolutionary Step.

    Science.gov (United States)

    Wodarz, Nan

    2001-01-01

    The Institute of Electrical and Electronics Engineers recently approved a high-speed wireless standard that enables devices from different manufacturers to communicate through a common backbone, making wireless local area networks more feasible in schools. Schools can now use wireless access points and network cards to provide flexible…

  14. Acquisition of CD-ROM Databases for Local Area Networks.

    Science.gov (United States)

    Davis, Trisha L.

    1993-01-01

    Discusses the acquisition of CD-ROM products for local area networks based on experiences at the Ohio State University libraries. Topics addressed include the historical development of CD-ROM acquisitions; database selection, including pricing and subscription options; the ordering process; and network licensing issues. (six references) (LRW)

  15. Local Area Networks for Libraries--Cast and Recast.

    Science.gov (United States)

    Tao, Dorothy S.

    1987-01-01

    Discusses the rationale, methodology, capabilities and problems of a local area network created for the Library Consortium of Health Institutions in Buffalo, using a multi-user microcomputer. The rationale and design of a new network, designed to better meet information and compatibility requirements, are described and suggestions to network…

  16. Local Area Networks: Effective Tools for Special Libraries.

    Science.gov (United States)

    Hoehl, Susan B.

    1988-01-01

    Examines technological changes in the local area network (LAN) of the Health Sciences Library of Allegheny General Hospital during three years of operation and describes the resulting evolution of staff, services, network requirements, budget, and external relationships of the library. LAN expenditures over four years are shown. (1 reference) (MES)

  17. Event localization in underwater wireless sensor networks using Monitoring Courses

    KAUST Repository

    Debont, Matthew John Robert

    2012-08-01

    We propose m-courses (Monitoring Courses), a novel solution to localize events in an underwater wireless sensor network. These networks consists of surface gateways and relay nodes. GPS can localize the position of surface gateways which can then distribute their locations through the network using acoustic modems. Relay nodes are deployed to remain static, but these untethered nodes may drift due to water currents, resulting in disruption of communication links. We develop a novel underwater alarm system using a cyclic graph model. In the event of link failure, a series of alarm packets are broadcast in the network. These alarms are then captured by the underwater m-courses, which can also be used to assure network connectivity and identify node failures. M-courses also allow the network to localize events and identify network issues locally before forwarding results upwards to a Surface Gateway node. This reduces communication overhead and allows for efficient management of nodes in a mobile network. Our results show that m-course routing reduces the number of sends required to report an event to a Surface Gateway by up to 80% when compared to a naïve routing implementation.

  18. Binaural Sound Localization Using Neural Networks

    Science.gov (United States)

    1991-12-12

    by Brennan, involved the implementation of a neural network to model the ability of a bat to discriminate between a mealworm and an inedible object...locate, identify and capture airborne prey (6:2). The sonar returns were collected from the mealworms , spheres and disks at various rotations (90 to

  19. An Overview of Computer Network security and Research Technology

    OpenAIRE

    Rathore, Vandana

    2016-01-01

    The rapid development in the field of computer networks and systems brings both convenience and security threats for users. Security threats include network security and data security. Network security refers to the reliability, confidentiality, integrity and availability of the information in the system. The main objective of network security is to maintain the authenticity, integrity, confidentiality, availability of the network. This paper introduces the details of the technologies used in...

  20. Enhancing Local and Distance Education with Computer-Produced Visuals.

    Science.gov (United States)

    Knupfer, Nancy Nelson

    The most common use of computers in distance education is in the preparation of a visual image that is somehow transmitted to students. This paper addresses some design considerations for computer-produced visual displays that are intended for either local or distant audiences. Advice is offered on all three basic components of information…

  1. Local spatial frequency analysis for computer vision

    Science.gov (United States)

    Krumm, John; Shafer, Steven A.

    1990-01-01

    A sense of vision is a prerequisite for a robot to function in an unstructured environment. However, real-world scenes contain many interacting phenomena that lead to complex images which are difficult to interpret automatically. Typical computer vision research proceeds by analyzing various effects in isolation (e.g., shading, texture, stereo, defocus), usually on images devoid of realistic complicating factors. This leads to specialized algorithms which fail on real-world images. Part of this failure is due to the dichotomy of useful representations for these phenomena. Some effects are best described in the spatial domain, while others are more naturally expressed in frequency. In order to resolve this dichotomy, we present the combined space/frequency representation which, for each point in an image, shows the spatial frequencies at that point. Within this common representation, we develop a set of simple, natural theories describing phenomena such as texture, shape, aliasing and lens parameters. We show these theories lead to algorithms for shape from texture and for dealiasing image data. The space/frequency representation should be a key aid in untangling the complex interaction of phenomena in images, allowing automatic understanding of real-world scenes.

  2. Cloud Computing for Network Security Intrusion Detection System

    Directory of Open Access Journals (Sweden)

    Jin Yang

    2013-01-01

    Full Text Available In recent years, as a new distributed computing model, cloud computing has developed rapidly and become the focus of academia and industry. But now the security issue of cloud computing is a main critical problem of most enterprise customers faced. In the current network environment, that relying on a single terminal to check the Trojan virus is considered increasingly unreliable. This paper analyzes the characteristics of current cloud computing, and then proposes a comprehensive real-time network risk evaluation model for cloud computing based on the correspondence between the artificial immune system antibody and pathogen invasion intensity. The paper also combines assets evaluation system and network integration evaluation system, considering from the application layer, the host layer, network layer may be factors that affect the network risks. The experimental results show that this model improves the ability of intrusion detection and can support for the security of current cloud computing.

  3. Computer Network Topology Design in Limelight of Pascal Graph Property

    CERN Document Server

    Pal, Sanjay Kumar; 10.5121/ijngn.2010.2103

    2010-01-01

    Constantly growing demands of high productivity and security of computer systems and computer networks call the interest of specialists in the environment of construction of optimum topologies of computer mediums. In earliest phases of design, the study of the topological influence of the processes that happen in computer systems and computer networks allows to obtain useful information which possesses a significant value in the subsequent design. It has always been tried to represent the different computer network topologies using appropriate graph models. Graphs have huge contributions towards the performance improvement factor of a network. Some major contributors are de-Bruijn, Hypercube, Mesh and Pascal. They had been studied a lot and different new features were always a part of research outcome. As per the definition of interconnection network it is equivalent that a suitable graph can represent the physical and logical layout very efficiently. In this present study Pascal graph is researched again and...

  4. Secure Localization and Tracking in Sensor Networks

    Science.gov (United States)

    2008-01-01

    To my parents, Yurng-Der Chang and Shiu-Mei Lee iii Biography Chih-Chieh Geoff Chang was born and raised in a beautiful resort town, Hualien, Taiwan...manufacturing and application needs. Currently, companies like Arch Rock, Crossbow, Dust Networks, Millennial Net, and Moteiv offer various types of sensor...activate one sensor node to make the measurement. This is the beauty of target tracking algorithms. Armed with the known models in (3.1) and (3.2), and

  5. Image-based Localization using Hourglass Networks

    OpenAIRE

    Melekhov, Iaroslav; Ylioinas, Juha; Kannala, Juho; Rahtu, Esa

    2017-01-01

    In this paper, we propose an encoder-decoder convolutional neural network (CNN) architecture for estimating camera pose (orientation and location) from a single RGB-image. The architecture has a hourglass shape consisting of a chain of convolution and up-convolution layers followed by a regression part. The up-convolution layers are introduced to preserve the fine-grained information of the input image. Following the common practice, we train our model in end-to-end manner utilizing transfer ...

  6. LocalMove: computing on-lattice fits for biopolymers

    Science.gov (United States)

    Ponty, Y.; Istrate, R.; Porcelli, E.; Clote, P.

    2008-01-01

    Given an input Protein Data Bank file (PDB) for a protein or RNA molecule, LocalMove is a web server that determines an on-lattice representation for the input biomolecule. The web server implements a Markov Chain Monte-Carlo algorithm with simulated annealing to compute an approximate fit for either the coarse-grain model or backbone model on either the cubic or face-centered cubic lattice. LocalMove returns a PDB file as output, as well as dynamic movie of 3D images of intermediate conformations during the computation. The LocalMove server is publicly available at http://bioinformatics.bc.edu/clotelab/localmove/. PMID:18556754

  7. Computational intelligence synergies of fuzzy logic, neural networks and evolutionary computing

    CERN Document Server

    Siddique, Nazmul

    2013-01-01

    Computational Intelligence: Synergies of Fuzzy Logic, Neural Networks and Evolutionary Computing presents an introduction to some of the cutting edge technological paradigms under the umbrella of computational intelligence. Computational intelligence schemes are investigated with the development of a suitable framework for fuzzy logic, neural networks and evolutionary computing, neuro-fuzzy systems, evolutionary-fuzzy systems and evolutionary neural systems. Applications to linear and non-linear systems are discussed with examples. Key features: Covers all the aspect

  8. Stability and Hopf Bifurcation in a Delayed SEIRS Worm Model in Computer Network

    Directory of Open Access Journals (Sweden)

    Zizhen Zhang

    2013-01-01

    Full Text Available A delayed SEIRS epidemic model with vertical transmission in computer network is considered. Sufficient conditions for local stability of the positive equilibrium and existence of local Hopf bifurcation are obtained by analyzing distribution of the roots of the associated characteristic equation. Furthermore, the direction of the local Hopf bifurcation and the stability of the bifurcating periodic solutions are determined by using the normal form theory and center manifold theorem. Finally, a numerical example is presented to verify the theoretical analysis.

  9. Study on the Cost Calculation of Local Fixed Telecom Network Based on Unbundled Network Elements

    Institute of Scientific and Technical Information of China (English)

    XU Liang; LIANG Xiong-jian; HUANG Xiu-qing

    2005-01-01

    In this paper, according to the practical condition of local fixed telecom network, based on the method of the realistic total element long-run incremental cost, the practical methods of dividing the network elements, calculating the cost of network elements and services are given, to provide reference for the cost calculation in telecom industry.

  10. Distributed Source Localization in Wireless Underground Sensor Networks

    CERN Document Server

    Chen, Hongyang; Wang, Chen

    2011-01-01

    Node localization plays an important role in many practical applications of wireless underground sensor networks (WUSNs), such as finding the locations of earthquake epicenters, underground explosions, and microseismic events in mines. It is more difficult to obtain the time-difference-of-arrival (TDOA) measurements in WUSNs than in terrestrial wireless sensor networks because of the unfavorable channel characteristics in the underground environment. The robust Chinese remainder theorem (RCRT) has been shown to be an effective tool for solving the phase ambiguity problem and frequency estimation problem in wireless sensor networks. In this paper, the RCRT is used to robustly estimate TDOA or range difference in WUSNs and therefore improves the ranging accuracy in such networks. After obtaining the range difference, distributed source localization algorithms based on a diffusion strategy are proposed to decrease the communication cost while satisfying the localization accuracy requirement. Simulation results c...

  11. Ethical Considerations of Computer Network Attack in Information Warfare

    Science.gov (United States)

    2001-01-16

    attack/destruction, and special information operations (SIO). CNA and the other methods of offensive IO represent the incorporation of information...psychological operations, electronic warfare, physical attack and/or destruction, and special information operations, and could include computer network...to computer networks to record information sent over them. 41 special information operations. Information operations that by their sensitive nature

  12. A simulation model of a star computer network

    CERN Document Server

    Gomaa, H

    1979-01-01

    A simulation model of the CERN (European Organization for Nuclear Research) SPS star computer network is described. The model concentrates on simulating the message handling computer, through which all messages in the network pass. The implementation of the model and its calibration are also described. (6 refs).

  13. Guest Editorial: Special Issue on Wireless Mobile Computing and Networking

    Institute of Scientific and Technical Information of China (English)

    Yu Wang; Yanwei Wu; Fan Li; Bin Xu; Teresa Dahlberg

    2011-01-01

    Recent convergence of information communications technology and computing is creating new demands and opportunities for ubiquitous computing via wireless and mobile equipments.The demanding networking environment of wireless communications and the fast-growing number of mobile users impose several challenges in terms of channel estimation,network protocol design,resource management,systematic design,application development,and security.The objective of this special issue is to gather recent advances addressing networks,systems,algorithms,and applications that support the symbiosis of mobile computers and wireless networks.

  14. Cascading failures in local-world evolving networks

    Institute of Scientific and Technical Information of China (English)

    Zhe-jing BAO; Yi-jia CAO

    2008-01-01

    The local-world (LW) evolving network model shows a transition for the degree distribution between the exponential and power-law distributions, depending on the LW size. Cascading failures under intentional attacks in LW network models with different LW sizes were investigated using the cascading failures load model. We found that the LW size has a significant impact on the network's robustness against deliberate attacks. It is much easier to trigger cascading failures in LW evolving networks with a larger LW size. Therefore, to avoid cascading failures in real networks with local preferential attachment such as the Internet, the World Trade Web and the multi-agent system, the LW size should be as small as possible.

  15. Generating weighted community networks based on local events

    Institute of Scientific and Technical Information of China (English)

    Xu Qi-Xin; Xu Xin-Jian

    2009-01-01

    realistic networks have community structures, namely, a network consists of groups of nodes within which links are dense but among which links are sparse. This paper proposes a growing network model based on local processes, the addition of new nodes intra-community and new links intra- or inter-community. Also, it utilizes the preferential attachment for building connections determined by nodes' strengths, which evolves dynamically during the growth of the system. The resulting network reflects the intrinsic community structure with generalized power-law distributions of nodes' degrees and strengths.

  16. Energy spectrum for a strongly correlated network and local magnetism

    Institute of Scientific and Technical Information of China (English)

    Li-li LIU; Qiao BI

    2009-01-01

    In this work, we consider a quantum strongly correlated network described by an Anderson s-d mixing model. By introducing the Green function on the projected formalism of the Schrieffer and Wolf transformation, the energy spectrum of the system can be obtained. Using this result we calculate the survivability distribution of the network and discuss the local magnetism in the network, which shows that the survivability is an important statistical characteristic quantity not just to reflect the network topological property but also dynamics.

  17. Cooperative Localization and Tracking in Distributed Robot-Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    ZHANG Fan; Guilherme S.Pereira; Vijay Kumar

    2005-01-01

    This paper addresses the problem of real-time position and orientation estimation of networked mobile robots in two-dimensional Euclidean space with simultaneous tracking of a rigid unknown object based on exteroceptive sensory information extracted from distributed vision systems. The sufficient and necessary conditions for team localization are proposed. A localization and object tracking approach based on statistical operators and graph searching algorithms is presented for a team of robots localized with heterogeneous sensors. The approach was implemented in an experimental platform consisting of car-like mobile robots equipped with omnidirectional video cameras and IEEE 802.11b wireless networking. The experimental results validate the approach.

  18. Grid Computing based on Game Optimization Theory for Networks Scheduling

    Directory of Open Access Journals (Sweden)

    Peng-fei Zhang

    2014-05-01

    Full Text Available The resource sharing mechanism is introduced into grid computing algorithm so as to solve complex computational tasks in heterogeneous network-computing problem. However, in the Grid environment, it is required for the available resource from network to reasonably schedule and coordinate, which can get a good workflow and an appropriate network performance and network response time. In order to improve the performance of resource allocation and task scheduling in grid computing method, a game model based on non-cooperation game is proposed. Setting the time and cost of user’s resource allocation can increase the performance of networks, and incentive resource of networks uses an optimization scheduling algorithm, which minimizes the time and cost of resource scheduling. Simulation experiment results show the feasibility and suitability of model. In addition, we can see from the experiment result that model-based genetic algorithm is the best resource scheduling algorithm

  19. Global and local knowledge networks in innovation

    DEFF Research Database (Denmark)

    Lorentzen, Anne

    2006-01-01

    Ideas of learning regions and regional innovation systems and innovation networks have for long been in focus in economic geography. The importance of geographic proximity between innovating partners is widely unquestioned and documented by studies of high-tech areas in advanced countries. Not much...... has been said until now about the pattern of cooperation among firms in low and medium tech industry in more peripheral locations. What patterns of knowledge sourcing can be detected in such industries? The article detects the pattern and role of knowledge sourcing of such firms. It looks at the type...

  20. A newself-localization method for wireless sensor networks

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Many applications of wireless sensor networks can benefit from fine-grained localization. In this paper, we proposed an accurate, distributed localization method based on the time difference between radio signal and sound wave. In a trilateration, each node adaptively chooses a neighborhood of sensors and updates its position estimate with trilateration, and then passes this update to neighboring sensors. Application examples demonstrate that the proposed method is more robust and accurate in localizing nod...

  1. 4th International Conference on Computer Engineering and Networks

    CERN Document Server

    2015-01-01

    This book aims to examine innovation in the fields of computer engineering and networking. The book covers important emerging topics in computer engineering and networking, and it will help researchers and engineers improve their knowledge of state-of-art in related areas. The book presents papers from the 4th International Conference on Computer Engineering and Networks (CENet2014) held July 19-20, 2014 in Shanghai, China.  ·       Covers emerging topics for computer engineering and networking ·       Discusses how to improve productivity by using the latest advanced technologies ·       Examines innovation in the fields of computer engineering and networking  

  2. Schedule-based sequential localization in asynchronous wireless networks

    Science.gov (United States)

    Zachariah, Dave; De Angelis, Alessio; Dwivedi, Satyam; Händel, Peter

    2014-12-01

    In this paper, we consider the schedule-based network localization concept, which does not require synchronization among nodes and does not involve communication overhead. The concept makes use of a common transmission sequence, which enables each node to perform self-localization and to localize the entire network, based on noisy propagation-time measurements. We formulate the schedule-based localization problem as an estimation problem in a Bayesian framework. This provides robustness with respect to uncertainty in such system parameters as anchor locations and timing devices. Moreover, we derive a sequential approximate maximum a posteriori (AMAP) estimator. The estimator is fully decentralized and copes with varying noise levels. By studying the fundamental constraints given by the considered measurement model, we provide a system design methodology which enables a scalable solution. Finally, we evaluate the performance of the proposed AMAP estimator by numerical simulations emulating an impulse-radio ultra-wideband (IR-UWB) wireless network.

  3. A local-world node deleting evolving network model

    Energy Technology Data Exchange (ETDEWEB)

    Gu Yuying [Department of Mathematics, Tongji University, Shanghai 200092 (China); Sun Jitao [Department of Mathematics, Tongji University, Shanghai 200092 (China)], E-mail: sunjt@sh163.net

    2008-06-16

    A new type network growth rule which comprises node addition with the concept of local-world connectivity and node deleting is studied. A series of theoretical analysis and numerical simulation to the LWD network are conducted in this Letter. Firstly, the degree distribution p(k) of this network changes no longer pure scale free but truncates by an exponential tail and the truncation in p(k) increases as p{sub a} decreases. Secondly, the connectivity is tighter, as the local-world size M increases. Thirdly, the average path length L increases and the clustering coefficient decreases as generally node deleting increases. Finally, trends up when the local-world size M increases, so as to k{sub max}. Hence, the expanding local-world can compensate the infection of the node deleting.

  4. Security of fixed and wireless computer networks

    NARCIS (Netherlands)

    Verschuren, J.; Degen, A.J.G.; Veugen, P.J.M.

    2003-01-01

    A few decades ago, most computers were stand-alone machines: they were able to process information using their own resources. Later, computer systems were connected to each other enabling a computer system to exchange data with another computer and to use resources of another computer. With the coup

  5. Security of fixed and wireless computer networks

    NARCIS (Netherlands)

    Verschuren, J.; Degen, A.J.G.; Veugen, P.J.M.

    2003-01-01

    A few decades ago, most computers were stand-alone machines: they were able to process information using their own resources. Later, computer systems were connected to each other enabling a computer system to exchange data with another computer and to use resources of another computer. With the coup

  6. Artificial Neural Network Metamodels of Stochastic Computer Simulations

    Science.gov (United States)

    1994-08-10

    SUBTITLE r 5. FUNDING NUMBERS Artificial Neural Network Metamodels of Stochastic I () Computer Simulations 6. AUTHOR(S) AD- A285 951 Robert Allen...8217!298*1C2 ARTIFICIAL NEURAL NETWORK METAMODELS OF STOCHASTIC COMPUTER SIMULATIONS by Robert Allen Kilmer B.S. in Education Mathematics, Indiana...dedicate this document to the memory of my father, William Ralph Kilmer. mi ABSTRACT Signature ARTIFICIAL NEURAL NETWORK METAMODELS OF STOCHASTIC

  7. An Algorithmic Approach to Wireless Sensor Networks Localization Using Rigid Graphs

    Directory of Open Access Journals (Sweden)

    Shamantha Rai B

    2016-01-01

    Full Text Available In this work estimating the position coordinates of Wireless Sensor Network nodes using the concept of rigid graphs is carried out in detail. The range based localization approaches use the distance information measured by the RSSI, which is prone to noise, due to effects of path loss, shadowing, and so forth. In this work, both the distance and the bearing information are used for localization using the trilateration technique. Rigid graph theory is employed to analyze the localizability, that is, whether the nodes of the WSN are uniquely localized. The WSN graph is divided into rigid patches by varying appropriately the communication power range of the WSN nodes and then localizing the patches by trilateration. The main advantage of localizing the network using rigid graph approach is that it overcomes the effect of noisy perturbed distance. Our approach gives a better performance compared to robust quads in terms of percentage of localizable nodes and computational complexity.

  8. Common neighbours and the local-community-paradigm for topological link prediction in bipartite networks

    Science.gov (United States)

    Daminelli, Simone; Thomas, Josephine Maria; Durán, Claudio; Vittorio Cannistraci, Carlo

    2015-11-01

    Bipartite networks are powerful descriptions of complex systems characterized by two different classes of nodes and connections allowed only across but not within the two classes. Unveiling physical principles, building theories and suggesting physical models to predict bipartite links such as product-consumer connections in recommendation systems or drug-target interactions in molecular networks can provide priceless information to improve e-commerce or to accelerate pharmaceutical research. The prediction of nonobserved connections starting from those already present in the topology of a network is known as the link-prediction problem. It represents an important subject both in many-body interaction theory in physics and in new algorithms for applied tools in computer science. The rationale is that the existing connectivity structure of a network can suggest where new connections can appear with higher likelihood in an evolving network, or where nonobserved connections are missing in a partially known network. Surprisingly, current complex network theory presents a theoretical bottle-neck: a general framework for local-based link prediction directly in the bipartite domain is missing. Here, we overcome this theoretical obstacle and present a formal definition of common neighbour index and local-community-paradigm (LCP) for bipartite networks. As a consequence, we are able to introduce the first node-neighbourhood-based and LCP-based models for topological link prediction that utilize the bipartite domain. We performed link prediction evaluations in several networks of different size and of disparate origin, including technological, social and biological systems. Our models significantly improve topological prediction in many bipartite networks because they exploit local physical driving-forces that participate in the formation and organization of many real-world bipartite networks. Furthermore, we present a local-based formalism that allows to intuitively

  9. Towards a Queueing-Based Framework for In-Network Function Computation

    CERN Document Server

    Banerjee, Siddhartha; Shakkottai, Sanjay

    2011-01-01

    We seek to develop network algorithms for function computation in sensor networks. Specifically, we want dynamic joint aggregation, routing, and scheduling algorithms that have analytically provable performance benefits due to in-network computation as compared to simple data forwarding. To this end, we define a class of functions, the Fully-Multiplexible functions, which includes several functions such as parity, MAX, and k th -order statistics. For such functions we exactly characterize the maximum achievable refresh rate of the network in terms of an underlying graph primitive, the min-mincut. In wireline networks, we show that the maximum refresh rate is achievable by a simple algorithm that is dynamic, distributed, and only dependent on local information. In the case of wireless networks, we provide a MaxWeight-like algorithm with dynamic flow splitting, which is shown to be throughput-optimal.

  10. Second International Conference on Advanced Computing, Networking and Informatics

    CERN Document Server

    Mohapatra, Durga; Konar, Amit; Chakraborty, Aruna

    2014-01-01

    Advanced Computing, Networking and Informatics are three distinct and mutually exclusive disciplines of knowledge with no apparent sharing/overlap among them. However, their convergence is observed in many real world applications, including cyber-security, internet banking, healthcare, sensor networks, cognitive radio, pervasive computing amidst many others. This two-volume proceedings explore the combined use of Advanced Computing and Informatics in the next generation wireless networks and security, signal and image processing, ontology and human-computer interfaces (HCI). The two volumes together include 148 scholarly papers, which have been accepted for presentation from over 640 submissions in the second International Conference on Advanced Computing, Networking and Informatics, 2014, held in Kolkata, India during June 24-26, 2014. The first volume includes innovative computing techniques and relevant research results in informatics with selective applications in pattern recognition, signal/image process...

  11. PlayNCool: Opportunistic Network Coding for Local Optimization of Routing in Wireless Mesh Networks

    DEFF Research Database (Denmark)

    Pahlevani, Peyman; Roetter, Daniel Enrique Lucani; Pedersen, Morten Videbæk;

    2013-01-01

    This paper introduces PlayNCool, an opportunistic protocol with local optimization based on network coding to increase the throughput of a wireless mesh network (WMN). PlayNCool aims to enhance current routing protocols by (i) allowing random linear network coding transmissions end-to-end, (ii...... in large scale mesh networks. We show that PlayNCool can provide gains of more than 3x in individual links, which translates into a large end-to-end throughput improvement, and that it provides higher gains when more nodes in the network contend for the channel at the MAC layer, making it particularly...... relevant for dense mesh networks....

  12. Spatiotemporal Dynamics and Reliable Computations in Recurrent Spiking Neural Networks

    Science.gov (United States)

    Pyle, Ryan; Rosenbaum, Robert

    2017-01-01

    Randomly connected networks of excitatory and inhibitory spiking neurons provide a parsimonious model of neural variability, but are notoriously unreliable for performing computations. We show that this difficulty is overcome by incorporating the well-documented dependence of connection probability on distance. Spatially extended spiking networks exhibit symmetry-breaking bifurcations and generate spatiotemporal patterns that can be trained to perform dynamical computations under a reservoir computing framework.

  13. A Computer Network for Social Scientists.

    Science.gov (United States)

    Gerber, Barry

    1989-01-01

    Describes a microcomputer-based network developed at the University of California Los Angeles to support education in the social sciences. Topics discussed include technological, managerial, and academic considerations of university networking; the use of the network in teaching macroeconomics, social demographics, and symbolic logic; and possible…

  14. Effects of local and global network connectivity on synergistic epidemics

    Science.gov (United States)

    Broder-Rodgers, David; Pérez-Reche, Francisco J.; Taraskin, Sergei N.

    2015-12-01

    Epidemics in networks can be affected by cooperation in transmission of infection and also connectivity between nodes. An interplay between these two properties and their influence on epidemic spread are addressed in the paper. A particular type of cooperative effects (called synergy effects) is considered, where the transmission rate between a pair of nodes depends on the number of infected neighbors. The connectivity effects are studied by constructing networks of different topology, starting with lattices with only local connectivity and then with networks that have both local and global connectivity obtained by random bond-rewiring to nodes within a certain distance. The susceptible-infected-removed epidemics were found to exhibit several interesting effects: (i) for epidemics with strong constructive synergy spreading in networks with high local connectivity, the bond rewiring has a negative role in epidemic spread, i.e., it reduces invasion probability; (ii) in contrast, for epidemics with destructive or weak constructive synergy spreading on networks of arbitrary local connectivity, rewiring helps epidemics to spread; (iii) and, finally, rewiring always enhances the spread of epidemics, independent of synergy, if the local connectivity is low.

  15. Distributed localization for anchor-free sensor networks

    Institute of Scientific and Technical Information of China (English)

    Cui Xunxue; Shan Zhiguan; Liu Jianjun

    2008-01-01

    Geographic location of nodes is very useful in a sensor network. Previous localization algorithms assume that there exist some anchor nodes in this kind of network, and then other nodes are estimated to create their coordinates. Once there are not anchors to be deployed, those localization algorithms will be invalidated. Many papers in this field focus on anchor-based solutions. The use of anchors introduces many limitations, since anchors require external equipments such as global position system, cause additional power consumption. A novel positioning algorithm is proposed to use a virtual coordinate system based on a new concept-virtual anchor. It is executed in a distributed fashion according to the connectivity of a node and the measured distances to its neighbors. Both the adjacent member information and the ranging distance result are combined to generate the estimated position of a network, one of which is independently adopted for localization previously. At the position refinement stage the intermediate estimation of a node begins to be evaluated on its reliability for position mutation; thus the positioning optimization process of the whole network is avoided falling into a local optimal solution. Simulation results prove that the algorithm can resolve the distributed localization problem for anchor-free sensor networks, and is superior to previous methods in terms of its positioning capability under a variety of circumstances.

  16. A Socially Aware Routing Based on Local Contact Information in Delay-Tolerant Networks

    Directory of Open Access Journals (Sweden)

    Chan-Myung Kim

    2014-01-01

    Full Text Available In delay-tolerant networks, network topology changes dynamically and there is no guarantee of continuous connectivity between any two nodes. These features make DTN routing one of important research issues, and the application of social network metrics has led to the design of recent DTN routing schemes. In this paper, we propose an efficient routing scheme by using a node’s local contact history and social network metrics. Each node first chooses a proper relay node based on the closeness to the destination node. A locally computed betweenness centrality is additionally utilized to enhance the routing efficiency. Through intensive simulation, we finally demonstrate that our algorithm performs efficiently compared to the existing epidemic or friendship routing scheme.

  17. Information Transmission and Anderson Localization in two-dimensional networks of firing-rate neurons

    Science.gov (United States)

    Natale, Joseph; Hentschel, George

    Firing-rate networks offer a coarse model of signal propagation in the brain. Here we analyze sparse, 2D planar firing-rate networks with no synapses beyond a certain cutoff distance. Additionally, we impose Dale's Principle to ensure that each neuron makes only or inhibitory outgoing connections. Using spectral methods, we find that the number of neurons participating in excitations of the network becomes insignificant whenever the connectivity cutoff is tuned to a value near or below the average interneuron separation. Further, neural activations exceeding a certain threshold stay confined to a small region of space. This behavior is an instance of Anderson localization, a disorder-induced phase transition by which an information channel is rendered unable to transmit signals. We discuss several potential implications of localization for both local and long-range computation in the brain. This work was supported in part by Grants JSMF/ 220020321 and NSF/IOS/1208126.

  18. A Least Square-Based Self-Adaptive Localization Method for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Baoguo Yu

    2016-01-01

    Full Text Available In the wireless sensor network (WSN localization methods based on Received Signal Strength Indicator (RSSI, it is usually required to determine the parameters of the radio signal propagation model before estimating the distance between the anchor node and an unknown node with reference to their communication RSSI value. And finally we use a localization algorithm to estimate the location of the unknown node. However, this localization method, though high in localization accuracy, has weaknesses such as complex working procedure and poor system versatility. Concerning these defects, a self-adaptive WSN localization method based on least square is proposed, which uses the least square criterion to estimate the parameters of radio signal propagation model, which positively reduces the computation amount in the estimation process. The experimental results show that the proposed self-adaptive localization method outputs a high processing efficiency while satisfying the high localization accuracy requirement. Conclusively, the proposed method is of definite practical value.

  19. A local immunization strategy for networks with overlapping community structure

    Science.gov (United States)

    Taghavian, Fatemeh; Salehi, Mostafa; Teimouri, Mehdi

    2017-02-01

    Since full coverage treatment is not feasible due to limited resources, we need to utilize an immunization strategy to effectively distribute the available vaccines. On the other hand, the structure of contact network among people has a significant impact on epidemics of infectious diseases (such as SARS and influenza) in a population. Therefore, network-based immunization strategies aim to reduce the spreading rate by removing the vaccinated nodes from contact network. Such strategies try to identify more important nodes in epidemics spreading over a network. In this paper, we address the effect of overlapping nodes among communities on epidemics spreading. The proposed strategy is an optimized random-walk based selection of these nodes. The whole process is local, i.e. it requires contact network information in the level of nodes. Thus, it is applicable to large-scale and unknown networks in which the global methods usually are unrealizable. Our simulation results on different synthetic and real networks show that the proposed method outperforms the existing local methods in most cases. In particular, for networks with strong community structures, high overlapping membership of nodes or small size communities, the proposed method shows better performance.

  20. Exploiting Locality in Quantum Computation for Quantum Chemistry.

    Science.gov (United States)

    McClean, Jarrod R; Babbush, Ryan; Love, Peter J; Aspuru-Guzik, Alán

    2014-12-18

    Accurate prediction of chemical and material properties from first-principles quantum chemistry is a challenging task on traditional computers. Recent developments in quantum computation offer a route toward highly accurate solutions with polynomial cost; however, this solution still carries a large overhead. In this Perspective, we aim to bring together known results about the locality of physical interactions from quantum chemistry with ideas from quantum computation. We show that the utilization of spatial locality combined with the Bravyi-Kitaev transformation offers an improvement in the scaling of known quantum algorithms for quantum chemistry and provides numerical examples to help illustrate this point. We combine these developments to improve the outlook for the future of quantum chemistry on quantum computers.

  1. Predictable nonwandering localization of covariant Lyapunov vectors and cluster synchronization in scale-free networks of chaotic maps.

    Science.gov (United States)

    Kuptsov, Pavel V; Kuptsova, Anna V

    2014-09-01

    Covariant Lyapunov vectors for scale-free networks of Hénon maps are highly localized. We revealed two mechanisms of the localization related to full and phase cluster synchronization of network nodes. In both cases the localization nodes remain unaltered in the course of the dynamics, i.e., the localization is nonwandering. Moreover, this is predictable: The localization nodes are found to have specific dynamical and topological properties and they can be found without computing of the covariant vectors. This is an example of explicit relations between the system topology, its phase-space dynamics, and the associated tangent-space dynamics of covariant Lyapunov vectors.

  2. Network selection, Information filtering and Scalable computation

    Science.gov (United States)

    Ye, Changqing

    This dissertation explores two application scenarios of sparsity pursuit method on large scale data sets. The first scenario is classification and regression in analyzing high dimensional structured data, where predictors corresponds to nodes of a given directed graph. This arises in, for instance, identification of disease genes for the Parkinson's diseases from a network of candidate genes. In such a situation, directed graph describes dependencies among the genes, where direction of edges represent certain causal effects. Key to high-dimensional structured classification and regression is how to utilize dependencies among predictors as specified by directions of the graph. In this dissertation, we develop a novel method that fully takes into account such dependencies formulated through certain nonlinear constraints. We apply the proposed method to two applications, feature selection in large margin binary classification and in linear regression. We implement the proposed method through difference convex programming for the cost function and constraints. Finally, theoretical and numerical analyses suggest that the proposed method achieves the desired objectives. An application to disease gene identification is presented. The second application scenario is personalized information filtering which extracts the information specifically relevant to a user, predicting his/her preference over a large number of items, based on the opinions of users who think alike or its content. This problem is cast into the framework of regression and classification, where we introduce novel partial latent models to integrate additional user-specific and content-specific predictors, for higher predictive accuracy. In particular, we factorize a user-over-item preference matrix into a product of two matrices, each representing a user's preference and an item preference by users. Then we propose a likelihood method to seek a sparsest latent factorization, from a class of over

  3. Learning without local minima in radial basis function networks.

    Science.gov (United States)

    Bianchini, M; Frasconi, P; Gori, M

    1995-01-01

    Learning from examples plays a central role in artificial neural networks. The success of many learning schemes is not guaranteed, however, since algorithms like backpropagation may get stuck in local minima, thus providing suboptimal solutions. For feedforward networks, optimal learning can be achieved provided that certain conditions on the network and the learning environment are met. This principle is investigated for the case of networks using radial basis functions (RBF). It is assumed that the patterns of the learning environment are separable by hyperspheres. In that case, we prove that the attached cost function is local minima free with respect to all the weights. This provides us with some theoretical foundations for a massive application of RBF in pattern recognition.

  4. Weighted Networks Model Based on Traffic Dynamics with Local Perturbation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In the study of weighted complex networks, the interplay between traffic and topology have been paid much attention. However, the variation of topology and weight brought by new added vertices or edges should also be considered. In this paper, an evolution model of weighted networks driven by traffic dynamics with local perturbation is proposed. The model gives power-law distribution of degree, weight and strength, as confirmed by empirical measurements. By choosing appropriate parameters W and δ, the exponents of various power law distributions can be adjusted to meet real world networks. Nontrivial clustering coefficient C, degree assortativity coefficient r, and strength-degree correlation are also considered. What should be emphasized is that, with the consideration of local perturbation, one can adjust the exponent of strength-degree correlation more effectively. It makes our model more general than previous ones and may help reproducing real world networks more appropriately.

  5. Quantify and Maximise Global Viral Influence Through Local Network Information

    CERN Document Server

    Hu, Yanqing; Feng, Ling; Jin, Yuliang

    2015-01-01

    Measuring and maximising the influence of individuals is the key to understand and leverage the multiplicative potential of viral spreading over social networks. Yet these have been recognized as problems requiring global structural information, and extremely difficult for the enormous size and complexity of online social networks. Based on the percolation phenomenon, we show that they can be essentially reduced to local problems. Our estimated global influence of individuals based on local structural information matches that of brute-force search. Furthermore this measure leads to an efficient algorithm to identify the best seed spreaders for maximum viral influence. Its time complexity is independent of network size, making it practically useful for real networks. The underlying theoretical framework enables a thorough analytical assessment of the prediction accuracy and the absolute performance of the proposed methods.

  6. A comparative analysis on computational methods for fitting an ERGM to biological network data

    Directory of Open Access Journals (Sweden)

    Sudipta Saha

    2015-03-01

    Full Text Available Exponential random graph models (ERGM based on graph theory are useful in studying global biological network structure using its local properties. However, computational methods for fitting such models are sensitive to the type, structure and the number of the local features of a network under study. In this paper, we compared computational methods for fitting an ERGM with local features of different types and structures. Two commonly used methods, such as the Markov Chain Monte Carlo Maximum Likelihood Estimation and the Maximum Pseudo Likelihood Estimation are considered for estimating the coefficients of network attributes. We compared the estimates of observed network to our random simulated network using both methods under ERGM. The motivation was to ascertain the extent to which an observed network would deviate from a randomly simulated network if the physical numbers of attributes were approximately same. Cut-off points of some common attributes of interest for different order of nodes were determined through simulations. We implemented our method to a known regulatory network database of Escherichia coli (E. coli.

  7. Effective local dynamic routing strategy for air route networks

    Institute of Scientific and Technical Information of China (English)

    Wu Wenjun; Zhao Lingxi

    2015-01-01

    With the rapid development of air transportation, network service ability has attracted a lot of attention in academe. Aiming to improve the throughput of the air route network (ARN), we propose an effective local dynamic routing strategy in this paper. Several factors, such as the rout-ing distance, the geographical distance and the real-time local traffic, are taken into consideration. When the ARN is in the normal free-flow state, the proposed strategy can recover the shortest path routing (SPR) strategy. When the ARN undergoes congestion, the proposed strategy changes the paths of flights based on the real-time local traffic information. The throughput of the Chinese air route network (CARN) is evaluated. Results confirm that the proposed strategy can significantly improve the throughput of CARN. Meanwhile, the increase in the average flying distance and time is tiny. Results also indicate the importance of the distance related factors in a routing strategy designed for the ARN.

  8. Computational capacity and energy consumption of complex resistive switch networks

    Directory of Open Access Journals (Sweden)

    Jens Bürger

    2015-12-01

    Full Text Available Resistive switches are a class of emerging nanoelectronics devices that exhibit a wide variety of switching characteristics closely resembling behaviors of biological synapses. Assembled into random networks, such resistive switches produce emerging behaviors far more complex than that of individual devices. This was previously demonstrated in simulations that exploit information processing within these random networks to solve tasks that require nonlinear computation as well as memory. Physical assemblies of such networks manifest complex spatial structures and basic processing capabilities often related to biologically-inspired computing. We model and simulate random resistive switch networks and analyze their computational capacities. We provide a detailed discussion of the relevant design parameters and establish the link to the physical assemblies by relating the modeling parameters to physical parameters. More globally connected networks and an increased network switching activity are means to increase the computational capacity linearly at the expense of exponentially growing energy consumption. We discuss a new modular approach that exhibits higher computational capacities, and energy consumption growing linearly with the number of networks used. The results show how to optimize the trade-o between computational capacity and energy e ciency and are relevant for the design and fabrication of novel computing architectures that harness random assemblies of emerging nanodevices.

  9. Qualia could arise from information processing in local cortical networks

    Directory of Open Access Journals (Sweden)

    Roger D Orpwood

    2013-03-01

    Full Text Available Re-entrant feedback, either within sensory cortex or arising from prefrontal areas, has been strongly linked to the emergence of consciousness, both in theoretical and experimental work. This idea, together with evidence for local micro-consciousness, suggests the generation of qualia could in some way result from local network activity under re-entrant activation. This paper explores the possibility by examining the processing of information by local cortical networks. It highlights the difference between the information structure (how the information is physically embodied, and the information message (what the information is about. It focuses on the network’s ability to recognise information structures amongst its inputs under conditions of extensive local feedback, and to then assign information messages to those structures. It is shown that if the re-entrant feedback enables the network to achieve an attractor state, then the message assigned in any given pass of information through the network is a representation of the message assigned in the previous pass-through of information. Based on this ability the paper argues that as information is repeatedly cycled through the network, the information message that is assigned evolves from a recognition of what the input structure is, to what it is like, to how it appears, to how it seems. It could enable individual networks to be the site of qualia generation. The paper goes on to show networks in cortical layers 2/3 and 5a have the connectivity required for the behaviour proposed, and reviews some evidence for a link between such local cortical cyclic activity and conscious percepts. It concludes with some predictions based on the theory discussed.

  10. Costs evaluation methodic of energy efficient computer network reengineering

    Directory of Open Access Journals (Sweden)

    S.A. Nesterenko

    2016-09-01

    Full Text Available A key direction of modern computer networks reengineering is their transfer to a new energy-saving technology IEEE 802.3az. To make a reasoned decision about the transition to the new technology is needed a technique that allows network engineers to answer the question about the economic feasibility of a network upgrade. Aim: The aim of this research is development of methodic for calculating the cost-effectiveness of energy-efficient computer network reengineering. Materials and Methods: The methodic uses analytical models for calculating power consumption of a computer network port operating in IEEE 802.3 standard and energy-efficient mode of IEEE 802.3az standard. For frame transmission time calculation in the communication channel used the queuing model. To determine the values of the network operation parameters proposed to use multiagent network monitoring method. Results: The methodic allows calculating the economic impact of a computer network transfer to energy-saving technology IEEE 802.3az. To determine the network performance parameters proposed to use network SNMP monitoring systems based on RMON MIB agents.

  11. Optical local area network emulations over Ethernet passive optical networks: A survey

    Institute of Scientific and Technical Information of China (English)

    PENG YunFeng; KUANG YuJun; LONG KePing

    2008-01-01

    As a promising solution to efficiently achieving fiber to the home (FTTH), Ethernet passive optical network (EPON) is currently improved to provide intercommunica-tion among customers, together with normal traffic delivery, via optical local area network emulation. It is a new research direction and expected to enhance the normal EPON performances. The purpose of this article is to review the state-of-the-art solutions to emulating optical local area networks (OLANs) over EPON. We discuss the major problems involved, e.g., network architecture, control mecha-nisms, and other potential enhancements. We also outline areas for future re-searches.

  12. Local area networks an introduction to the technology

    CERN Document Server

    McNamara, John E

    1985-01-01

    This concise book provides an objective introduction to local area networks - how they work, what they do, and how you can benefit from them. It outlines the pros and cons of the most common configurations so you can evaluate them in light of your own needs. You'll also learn about network software, with special emphasis on the ISO layered model of communications protocols.

  13. The computational power of interactive recurrent neural networks.

    Science.gov (United States)

    Cabessa, Jérémie; Siegelmann, Hava T

    2012-04-01

    In classical computation, rational- and real-weighted recurrent neural networks were shown to be respectively equivalent to and strictly more powerful than the standard Turing machine model. Here, we study the computational power of recurrent neural networks in a more biologically oriented computational framework, capturing the aspects of sequential interactivity and persistence of memory. In this context, we prove that so-called interactive rational- and real-weighted neural networks show the same computational powers as interactive Turing machines and interactive Turing machines with advice, respectively. A mathematical characterization of each of these computational powers is also provided. It follows from these results that interactive real-weighted neural networks can perform uncountably many more translations of information than interactive Turing machines, making them capable of super-Turing capabilities.

  14. 3rd International Conference on Advanced Computing, Networking and Informatics

    CERN Document Server

    Mohapatra, Durga; Chaki, Nabendu

    2016-01-01

    Advanced Computing, Networking and Informatics are three distinct and mutually exclusive disciplines of knowledge with no apparent sharing/overlap among them. However, their convergence is observed in many real world applications, including cyber-security, internet banking, healthcare, sensor networks, cognitive radio, pervasive computing amidst many others. This two volume proceedings explore the combined use of Advanced Computing and Informatics in the next generation wireless networks and security, signal and image processing, ontology and human-computer interfaces (HCI). The two volumes together include 132 scholarly articles, which have been accepted for presentation from over 550 submissions in the Third International Conference on Advanced Computing, Networking and Informatics, 2015, held in Bhubaneswar, India during June 23–25, 2015.

  15. Fault Detection of Computer Communication Networks Using an Expert System

    Directory of Open Access Journals (Sweden)

    Ibrahiem M.M. El Emary

    2005-01-01

    Full Text Available The main objective of this study was to build an expert system for assisting the network administrator in his work of management and administration of the computer communication network. Theory of operation of the proposed expert system depends on using a time series model capable of forecasting the various performance parameters as: delay, utilization and collision frequency. When the expert system finds a difference (with certain tolerance between the predicted value and the measured value, it informs the network administrator that there exist problems in his network either in the switch or link or router. We examine two types of network by our proposed expert system, the first one is called token bus while the second one is called token ring. When we run our expert system on these two types of computer networks, actually the expert system captures the problem when there exists an excess deviation from the network performance parameters.

  16. Correlation and network topologies in global and local stock indices

    Science.gov (United States)

    Nobi, Ashadun; Lee, Sungmin; Kim, Doo Hwan; Lee, Jae Woo

    2014-07-01

    We examined how the correlation and network structure of the global indices and local Korean indices have changed during years 2000-2012. The average correlations of the global indices increased with time, while the local indices showed a decreasing trend except for drastic changes during the crises. A significant change in the network topologies was observed due to the financial crises in both markets. The Jaccard similarities identified the change in the market state due to a crisis in both markets. The dynamic change of the Jaccard index can be used as an indicator of systemic risk or precursors of the crisis.

  17. Correlation and network topologies in global and local stock indices

    DEFF Research Database (Denmark)

    Nobi, A.; Lee, S.; Kim, D. H.;

    2014-01-01

    the crises. A significant change in the network topologies was observed due to the financial crises in both markets. The Jaccard similarities identified the change in the market state due to a crisis in both markets. The dynamic change of the Jaccard index can be used as an indicator of systemic risk......We examined how the correlation and network structure of the global indices and local Korean indices have changed during years 2000-2012. The average correlations of the global indices increased with time, while the local indices showed a decreasing trend except for drastic changes during...

  18. Traffic optimization in transport networks based on local routing

    Science.gov (United States)

    Scellato, S.; Fortuna, L.; Frasca, M.; Gómez-Gardeñes, J.; Latora, V.

    2010-01-01

    Congestion in transport networks is a topic of theoretical interest and practical importance. In this paper we study the flow of vehicles in urban street networks. In particular, we use a cellular automata model on a complex network to simulate the motion of vehicles along streets, coupled with a congestion-aware routing at street crossings. Such routing makes use of the knowledge of agents about traffic in nearby roads and allows the vehicles to dynamically update the routes towards their destinations. By implementing the model in real urban street patterns of various cities, we show that it is possible to achieve a global traffic optimization based on local agent decisions.

  19. A programmable interface to neuromolecular computing networks.

    Science.gov (United States)

    Akingbehin, K

    1995-01-01

    A programmable interface is provided to a simulated network of reaction-diffusion neurons. The interface allows special 'learn' and 'decide' syntactic constructs to be intermixed with conventional programming constructs. This hybrid combination allows the power of programmability to be combined with the power of adaptability to provide innovative solutions to complex problems. The network uses reaction-diffusion neurons instead of adaline neurons. A mesh topology is used instead of a feedforward topology. The performance of the mesh reaction-diffusion network compares favorably with that of conventional feedforward adaline networks. Enhancements to incorporate short- and long-term memory are described.

  20. Random matrix analysis of localization properties of gene coexpression network.

    Science.gov (United States)

    Jalan, Sarika; Solymosi, Norbert; Vattay, Gábor; Li, Baowen

    2010-04-01

    We analyze gene coexpression network under the random matrix theory framework. The nearest-neighbor spacing distribution of the adjacency matrix of this network follows Gaussian orthogonal statistics of random matrix theory (RMT). Spectral rigidity test follows random matrix prediction for a certain range and deviates afterwards. Eigenvector analysis of the network using inverse participation ratio suggests that the statistics of bulk of the eigenvalues of network is consistent with those of the real symmetric random matrix, whereas few eigenvalues are localized. Based on these IPR calculations, we can divide eigenvalues in three sets: (a) The nondegenerate part that follows RMT. (b) The nondegenerate part, at both ends and at intermediate eigenvalues, which deviates from RMT and expected to contain information about important nodes in the network. (c) The degenerate part with zero eigenvalue, which fluctuates around RMT-predicted value. We identify nodes corresponding to the dominant modes of the corresponding eigenvectors and analyze their structural properties.

  1. A New Method for Computing Attention Network Scores and Relationships between Attention Networks

    OpenAIRE

    Yi-Feng Wang; Qian Cui; Feng Liu; Ya-Jun Huo; Feng-Mei Lu; Heng Chen; Hua-Fu Chen

    2014-01-01

    The attention network test (ANT) is a reliable tool to detect the efficiency of alerting, orienting, and executive control networks. However, studies using the ANT obtained inconsistent relationships between attention networks due to two reasons: on the one hand, the inter-network relationships of attention subsystems were far from clear; on the other hand, ANT scores in previous studies were disturbed by possible inter-network interactions. Here we proposed a new computing method by dissecti...

  2. Self-organization of network dynamics into local quantized states.

    Science.gov (United States)

    Nicolaides, Christos; Juanes, Ruben; Cueto-Felgueroso, Luis

    2016-02-17

    Self-organization and pattern formation in network-organized systems emerges from the collective activation and interaction of many interconnected units. A striking feature of these non-equilibrium structures is that they are often localized and robust: only a small subset of the nodes, or cell assembly, is activated. Understanding the role of cell assemblies as basic functional units in neural networks and socio-technical systems emerges as a fundamental challenge in network theory. A key open question is how these elementary building blocks emerge, and how they operate, linking structure and function in complex networks. Here we show that a network analogue of the Swift-Hohenberg continuum model-a minimal-ingredients model of nodal activation and interaction within a complex network-is able to produce a complex suite of localized patterns. Hence, the spontaneous formation of robust operational cell assemblies in complex networks can be explained as the result of self-organization, even in the absence of synaptic reinforcements.

  3. Self-organization of network dynamics into local quantized states

    CERN Document Server

    Nicolaides, Christos; Cueto-Felgueroso, Luis

    2015-01-01

    Self-organization and pattern formation in network-organized systems emerges from the collective activation and interaction of many interconnected units. A striking feature of these non-equilibrium structures is that they are often localized and robust: only a small subset of the nodes, or cell assembly, is activated. Understanding the role of cell assemblies as basic functional units in neural networks and socio-technical systems emerges as a fundamental challenge in network theory. A key open question is how these elementary building blocks emerge, and how they operate, linking structure and function in complex networks. Here we show that a network analogue of the Swift-Hohenberg continuum model---a minimal-ingredients model of nodal activation and interaction within a complex network---is able to produce a complex suite of localized patterns. Hence, the spontaneous formation of robust operational cell assemblies in complex networks can be explained as the result of self-organization, even in the absence of...

  4. Fundamental Limits of Wideband Localization - Part II: Cooperative Networks

    CERN Document Server

    Shen, Yuan; Win, Moe Z

    2010-01-01

    The availability of positional information is of great importance in many commercial, governmental, and military applications. Localization is commonly accomplished through the use of radio communication between mobile devices (agents) and fixed infrastructure (anchors). However, precise determination of agent positions is a challenging task, especially in harsh environments due to radio blockage or limited anchor deployment. In these situations, cooperation among agents can significantly improve localization accuracy and reduce localization outage probabilities. A general framework of analyzing the fundamental limits of wideband localization has been developed in Part I of the paper. Here, we build on this framework and establish the fundamental limits of wideband cooperative location-aware networks. Our analysis is based on the waveforms received at the nodes, in conjunction with Fisher information inequality. We provide a geometrical interpretation of equivalent Fisher information for cooperative networks....

  5. A Practical Localization Algorithm Based on Wireless Sensor Networks

    CERN Document Server

    Huang, Tao; Xia, Feng; Jin, Cheng; Li, Liang

    2010-01-01

    Many localization algorithms and systems have been developed by means of wireless sensor networks for both indoor and outdoor environments. To achieve higher localization accuracy, extra hardware equipments are utilized by most of the existing localization algorithms, which increase the cost and greatly limit the range of location-based applications. In this paper we present a method which can effectively meet different localization accuracy requirements of most indoor and outdoor location services in realistic applications. Our algorithm is composed of two phases: partition phase, in which the target region is split into small grids and localization refinement phase in which a higher accuracy location can be generated by applying a trick algorithm. A realistic demo system using our algorithm has been developed to illustrate its feasibility and availability. The results show that our algorithm can improve the localization accuracy.

  6. Mobile Anchor Assisted Node Localization for Wireless Sensor Networks

    CERN Document Server

    Chen, Hongyang; Huang, Pei; Poor, H Vincent; Sezaki, Kaoru

    2009-01-01

    In this paper, a cooperative localization algorithm is proposed that considers the existence of obstacles in mobilityassisted wireless sensor networks (WSNs). In this scheme, a mobile anchor (MA) node cooperates with static sensor nodes and moves actively to refine location performance. The localization accuracy of the proposed algorithm can be improved further by changing the transmission range of mobile anchor node. The algorithm takes advantage of cooperation betweenMAs and static sensors while, at the same time, taking into account the relay node availability to make the best use of beacon signals. For achieving high localization accuracy and coverage, a novel convex position estimation algorithm is proposed, which can effectively solve the localization problem when infeasible points occur because of the effects of radio irregularity and obstacles. This method is the only range-free based convex method to solve the localization problem when the feasible set of localization inequalities is empty. Simulatio...

  7. Parallel CFD design on network-based computer

    Science.gov (United States)

    Cheung, Samson

    1995-01-01

    Combining multiple engineering workstations into a network-based heterogeneous parallel computer allows application of aerodynamic optimization with advanced computational fluid dynamics codes, which can be computationally expensive on mainframe supercomputers. This paper introduces a nonlinear quasi-Newton optimizer designed for this network-based heterogeneous parallel computing environment utilizing a software called Parallel Virtual Machine. This paper will introduce the methodology behind coupling a Parabolized Navier-Stokes flow solver to the nonlinear optimizer. This parallel optimization package is applied to reduce the wave drag of a body of revolution and a wing/body configuration with results of 5% to 6% drag reduction.

  8. A Brief Talk on Teaching Reform Program of Computer Network Course System about Computer Related Professional

    Institute of Scientific and Technical Information of China (English)

    Wang Jian-Ping; Huang Yong

    2008-01-01

    The computer network course is the mainstay required course that college computer-related professional sets up,in regard to current teaching condition analysis,the teaching of this course has not formed a complete system,the new knowledge points can be added in promptly while the outdated technology is still there in teaching The article describes the current situation and maladies which appears in the university computer network related professional teaching,the teaching systems and teaching reform schemes about the computer network coupe are presented.

  9. Phoebus: Network Middleware for Next-Generation Network Computing

    Energy Technology Data Exchange (ETDEWEB)

    Martin Swany

    2012-06-16

    The Phoebus project investigated algorithms, protocols, and middleware infrastructure to improve end-to-end performance in high speed, dynamic networks. The Phoebus system essentially serves as an adaptation point for networks with disparate capabilities or provisioning. This adaptation can take a variety of forms including acting as a provisioning agent across multiple signaling domains, providing transport protocol adaptation points, and mapping between distributed resource reservation paradigms and the optical network control plane. We have successfully developed the system and demonstrated benefits. The Phoebus system was deployed in Internet2 and in ESnet, as well as in GEANT2, RNP in Brazil and over international links to Korea and Japan. Phoebus is a system that implements a new protocol and associated forwarding infrastructure for improving throughput in high-speed dynamic networks. It was developed to serve the needs of large DOE applications on high-performance networks. The idea underlying the Phoebus model is to embed Phoebus Gateways (PGs) in the network as on-ramps to dynamic circuit networks. The gateways act as protocol translators that allow legacy applications to use dedicated paths with high performance.

  10. A comprehensive multi-local-world model for complex networks

    Energy Technology Data Exchange (ETDEWEB)

    Fan Zhengping [Department of Automation, Sun Yat-sen University, Guangzhou 510275 (China); Chen Guanrong [Department of Electronic and Engineering, City University of Hong Kong, Hong Kong (China)], E-mail: eegchen@cityu.edu.hk; Zhang Yunong [Department of Automation, Sun Yat-sen University, Guangzhou 510275 (China)

    2009-04-20

    The nodes in a community within a network are much more connected to each other than to the others outside the community in the same network. This phenomenon has been commonly observed from many real-world networks, ranging from social to biological even to technical networks. Meanwhile, the number of communities in some real-world networks, such as the Internet and most social networks, are evolving with time. To model this kind of networks, the present Letter proposes a multi-local-world (MLW) model to capture and describe their essential topological properties. Based on the mean-field theory, the degree distribution of this model is obtained analytically, showing that the generated network has a novel topological feature as being not completely random nor completely scale-free but behaving somewhere between them. As a typical application, the MLW model is applied to characterize the Internet against some other models such as the BA, GBA, Fitness and HOT models, demonstrating the superiority of the new model.

  11. Global, Computer-generated Map of Valley Networks on Mars

    Science.gov (United States)

    Luo, W.; Stepinski, T. F.

    2009-03-01

    The new, global map of valley networks on Mars has been created entirely by a computer algorithm parsing topographic data. Dependencies between dissection density and its potential controlling factors are derived and discussed.

  12. The Local Area Network (LAN) and Library Automation.

    Science.gov (United States)

    Farr, Rick C.

    1983-01-01

    Discussion of the use of inexpensive microcomputers in local area information networks (LAN) notes such minicomputer problems as costs, capacity, downtime, and vendor dependence, and the advantages of using LAN in offices and libraries, less costly LAN upgrades, library vendors and LAN systems, and LAN problems. A 28-item bibliography is provided.…

  13. Applications of Local Area Networks of Microcomputers in Libraries.

    Science.gov (United States)

    Levert, Virginia M.

    1985-01-01

    Important features of local area networks (LAN) are reviewed, and several microcomputer LANs are described (ARCnet, Hinet, ShareNet, Ethernet, Omninet, PLAN 4000). Results of survey of 10 libraries using or planning to use a microcomputer LAN and considerations in choosing a LAN are reported. Forty-one references are cited. (EJS)

  14. Local Area Networks (LAN) in the Special Library.

    Science.gov (United States)

    Angier, Jennifer J.; Hoehl, Susan B.

    1986-01-01

    Presents a planning model for the automation of operations in a large hospital library and specifically describes the design and implementation of a local area network. Part 1 deals with the evolution of the idea, system planning, and design, and Part 2 addresses installation and implementation issues. (EM)

  15. Local Area Network Implementation: Moving toward Phase III.

    Science.gov (United States)

    Hoehl, Susan B.

    1989-01-01

    Describes a LAN (local area network)-based automation project which has neared completion of the first phase of implementation at the Health Sciences Library of Allegheny General Hospital (Pittsburgh, PA). Changes in the library and its objectives with increased technological experience are examined. Diagrams of the current LAN configuration and…

  16. Bayesian Network Models for Local Dependence among Observable Outcome Variables

    Science.gov (United States)

    Almond, Russell G.; Mulder, Joris; Hemat, Lisa A.; Yan, Duanli

    2009-01-01

    Bayesian network models offer a large degree of flexibility for modeling dependence among observables (item outcome variables) from the same task, which may be dependent. This article explores four design patterns for modeling locally dependent observations: (a) no context--ignores dependence among observables; (b) compensatory context--introduces…

  17. Localization with Imprecise Distance Information in Sensor Networks

    NARCIS (Netherlands)

    Cao, M.; Anderson, B.D.O.; Morse, A.S.

    2005-01-01

    An approach to formulate geometric relations among distances between nodes as equality constraints is introduced in this paper to study the localization problem with imprecise distance information in sensor networks. These constraints can be further used to formulate optimization problems for distan

  18. Ecological Citizenship and Sustainable Consumption: Examining Local Organic Food Networks

    Science.gov (United States)

    Seyfang, Gill

    2006-01-01

    Sustainable consumption is gaining in currency as a new environmental policy objective. This paper presents new research findings from a mixed-method empirical study of a local organic food network to interrogate the theories of both sustainable consumption and ecological citizenship. It describes a mainstream policy model of sustainable…

  19. Ecological Citizenship and Sustainable Consumption: Examining Local Organic Food Networks

    Science.gov (United States)

    Seyfang, Gill

    2006-01-01

    Sustainable consumption is gaining in currency as a new environmental policy objective. This paper presents new research findings from a mixed-method empirical study of a local organic food network to interrogate the theories of both sustainable consumption and ecological citizenship. It describes a mainstream policy model of sustainable…

  20. Localization and Communication for UWB-based Wireless Sensor Networks

    NARCIS (Netherlands)

    Wang, Y.

    2011-01-01

    The great demand for location-aware wireless sensor networks (WSNs) motivates the research in this thesis. The unique characteristics of WSNs impose numerous challenges on localization and communication. In this thesis, we handle some key challenges and provide affordable solutions. Impulse radio u

  1. Study of space wireless local area network application

    Science.gov (United States)

    Zhang, Qingjun

    2005-11-01

    This paper describes the standards about wireless local area network (WLAN), and discusses the applications in formatting satellite and the types of WLAN, and give one type of WLAN conception which is Bus/Token-Ring. Finally, it describes some key technologies of the space WLAN.

  2. Computationally Efficient Neural Network Intrusion Security Awareness

    Energy Technology Data Exchange (ETDEWEB)

    Todd Vollmer; Milos Manic

    2009-08-01

    An enhanced version of an algorithm to provide anomaly based intrusion detection alerts for cyber security state awareness is detailed. A unique aspect is the training of an error back-propagation neural network with intrusion detection rule features to provide a recognition basis. Network packet details are subsequently provided to the trained network to produce a classification. This leverages rule knowledge sets to produce classifications for anomaly based systems. Several test cases executed on ICMP protocol revealed a 60% identification rate of true positives. This rate matched the previous work, but 70% less memory was used and the run time was reduced to less than 1 second from 37 seconds.

  3. Computationally Efficient Neural Network Intrusion Security Awareness

    Energy Technology Data Exchange (ETDEWEB)

    Todd Vollmer; Milos Manic

    2009-08-01

    An enhanced version of an algorithm to provide anomaly based intrusion detection alerts for cyber security state awareness is detailed. A unique aspect is the training of an error back-propagation neural network with intrusion detection rule features to provide a recognition basis. Network packet details are subsequently provided to the trained network to produce a classification. This leverages rule knowledge sets to produce classifications for anomaly based systems. Several test cases executed on ICMP protocol revealed a 60% identification rate of true positives. This rate matched the previous work, but 70% less memory was used and the run time was reduced to less than 1 second from 37 seconds.

  4. On Event Detection and Localization in Acyclic Flow Networks

    KAUST Repository

    Suresh, Mahima Agumbe

    2013-05-01

    Acyclic flow networks, present in many infrastructures of national importance (e.g., oil and gas and water distribution systems), have been attracting immense research interest. Existing solutions for detecting and locating attacks against these infrastructures have been proven costly and imprecise, particularly when dealing with large-scale distribution systems. In this article, to the best of our knowledge, for the first time, we investigate how mobile sensor networks can be used for optimal event detection and localization in acyclic flow networks. We propose the idea of using sensors that move along the edges of the network and detect events (i.e., attacks). To localize the events, sensors detect proximity to beacons, which are devices with known placement in the network. We formulate the problem of minimizing the cost of monitoring infrastructure (i.e., minimizing the number of sensors and beacons deployed) in a predetermined zone of interest, while ensuring a degree of coverage by sensors and a required accuracy in locating events using beacons. We propose algorithms for solving the aforementioned problem and demonstrate their effectiveness with results obtained from a realistic flow network simulator.

  5. Self-organization of network dynamics into local quantized states

    Science.gov (United States)

    Nicolaides, Christos; Juanes, Ruben; Cueto-Felgueroso, Luis

    2016-02-01

    Self-organization and pattern formation in network-organized systems emerges from the collective activation and interaction of many interconnected units. A striking feature of these non-equilibrium structures is that they are often localized and robust: only a small subset of the nodes, or cell assembly, is activated. Understanding the role of cell assemblies as basic functional units in neural networks and socio-technical systems emerges as a fundamental challenge in network theory. A key open question is how these elementary building blocks emerge, and how they operate, linking structure and function in complex networks. Here we show that a network analogue of the Swift-Hohenberg continuum model—a minimal-ingredients model of nodal activation and interaction within a complex network—is able to produce a complex suite of localized patterns. Hence, the spontaneous formation of robust operational cell assemblies in complex networks can be explained as the result of self-organization, even in the absence of synaptic reinforcements.

  6. Computer Network Security: Best Practices for Alberta School Jurisdictions.

    Science.gov (United States)

    Alberta Dept. of Education, Edmonton.

    This paper provides a snapshot of the computer network security industry and addresses specific issues related to network security in public education. The following topics are covered: (1) security policy, including reasons for establishing a policy, risk assessment, areas to consider, audit tools; (2) workstations, including physical security,…

  7. Evolving ATLAS Computing For Today’s Networks

    CERN Document Server

    Campana, S; The ATLAS collaboration; Jezequel, S; Negri, G; Serfon, C; Ueda, I

    2012-01-01

    The ATLAS computing infrastructure was designed many years ago based on the assumption of rather limited network connectivity between computing centres. ATLAS sites have been organized in a hierarchical model, where only a static subset of all possible network links can be exploited and a static subset of well connected sites (CERN and the T1s) can cover important functional roles such as hosting master copies of the data. The pragmatic adoption of such simplified approach, in respect of a more relaxed scenario interconnecting all sites, was very beneficial during the commissioning of the ATLAS distributed computing system and essential in reducing the operational cost during the first two years of LHC data taking. In the mean time, networks evolved far beyond this initial scenario: while a few countries are still poorly connected with the rest of the WLCG infrastructure, most of the ATLAS computing centres are now efficiently interlinked. Our operational experience in running the computing infrastructure in ...

  8. Virtual Network Computing Testbed for Cybersecurity Research

    Science.gov (United States)

    2015-08-17

    Standard Form 298 (Rev 8/98) Prescribed by ANSI Std. Z39.18 212-346-1012 W911NF-12-1-0393 61504-CS- RIP .2 Final Report a. REPORT 14. ABSTRACT 16...traffic on the network, either by using mathematical formulas or by replaying packet streams . As a result, simulators depend deeply on the assumptions...traffic, not simulated packet streams , and to enable real attacks to be launched. The need for realism eliminated network simulators from consideration

  9. An Effective Cuckoo Search Algorithm for Node Localization in Wireless Sensor Network.

    Science.gov (United States)

    Cheng, Jing; Xia, Linyuan

    2016-08-31

    Localization is an essential requirement in the increasing prevalence of wireless sensor network (WSN) applications. Reducing the computational complexity, communication overhead in WSN localization is of paramount importance in order to prolong the lifetime of the energy-limited sensor nodes and improve localization performance. This paper proposes an effective Cuckoo Search (CS) algorithm for node localization. Based on the modification of step size, this approach enables the population to approach global optimal solution rapidly, and the fitness of each solution is employed to build mutation probability for avoiding local convergence. Further, the approach restricts the population in the certain range so that it can prevent the energy consumption caused by insignificant search. Extensive experiments were conducted to study the effects of parameters like anchor density, node density and communication range on the proposed algorithm with respect to average localization error and localization success ratio. In addition, a comparative study was conducted to realize the same localization task using the same network deployment. Experimental results prove that the proposed CS algorithm can not only increase convergence rate but also reduce average localization error compared with standard CS algorithm and Particle Swarm Optimization (PSO) algorithm.

  10. A reverse localization scheme for underwater acoustic sensor networks.

    Science.gov (United States)

    Moradi, Marjan; Rezazadeh, Javad; Ismail, Abdul Samad

    2012-01-01

    Underwater Wireless Sensor Networks (UWSNs) provide new opportunities to observe and predict the behavior of aquatic environments. In some applications like target tracking or disaster prevention, sensed data is meaningless without location information. In this paper, we propose a novel 3D centralized, localization scheme for mobile underwater wireless sensor network, named Reverse Localization Scheme or RLS in short. RLS is an event-driven localization method triggered by detector sensors for launching localization process. RLS is suitable for surveillance applications that require very fast reactions to events and could report the location of the occurrence. In this method, mobile sensor nodes report the event toward the surface anchors as soon as they detect it. They do not require waiting to receive location information from anchors. Simulation results confirm that the proposed scheme improves the energy efficiency and reduces significantly localization response time with a proper level of accuracy in terms of mobility model of water currents. Major contributions of this method lie on reducing the numbers of message exchange for localization, saving the energy and decreasing the average localization response time.

  11. Agent Collaborative Target Localization and Classification in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sheng Wang

    2007-07-01

    Full Text Available Wireless sensor networks (WSNs are autonomous networks that have beenfrequently deployed to collaboratively perform target localization and classification tasks.Their autonomous and collaborative features resemble the characteristics of agents. Suchsimilarities inspire the development of heterogeneous agent architecture for WSN in thispaper. The proposed agent architecture views WSN as multi-agent systems and mobileagents are employed to reduce in-network communication. According to the architecture,an energy based acoustic localization algorithm is proposed. In localization, estimate oftarget location is obtained by steepest descent search. The search algorithm adapts tomeasurement environments by dynamically adjusting its termination condition. With theagent architecture, target classification is accomplished by distributed support vectormachine (SVM. Mobile agents are employed for feature extraction and distributed SVMlearning to reduce communication load. Desirable learning performance is guaranteed bycombining support vectors and convex hull vectors. Fusion algorithms are designed tomerge SVM classification decisions made from various modalities. Real world experimentswith MICAz sensor nodes are conducted for vehicle localization and classification.Experimental results show the proposed agent architecture remarkably facilitates WSNdesigns and algorithm implementation. The localization and classification algorithms alsoprove to be accurate and energy efficient.

  12. Local-basis-function approach to computed tomography

    Science.gov (United States)

    Hanson, K. M.; Wecksung, G. W.

    1985-12-01

    In the local basis-function approach, a reconstruction is represented as a linear expansion of basis functions, which are arranged on a rectangular grid and possess a local region of support. The basis functions considered here are positive and may overlap. It is found that basis functions based on cubic B-splines offer significant improvements in the calculational accuracy that can be achieved with iterative tomographic reconstruction algorithms. By employing repetitive basis functions, the computational effort involved in these algorithms can be minimized through the use of tabulated values for the line or strip integrals over a single-basis function. The local nature of the basis functions reduces the difficulties associated with applying local constraints on reconstruction values, such as upper and lower limits. Since a reconstruction is specified everywhere by a set of coefficients, display of a coarsely represented image does not require an arbitrary choice of an interpolation function.

  13. Communities of minima in local optima networks of combinatorial spaces

    Science.gov (United States)

    Daolio, Fabio; Tomassini, Marco; Vérel, Sébastien; Ochoa, Gabriela

    2011-05-01

    In this work, we present a new methodology to study the structure of the configuration spaces of hard combinatorial problems. It consists in building the network that has as nodes the locally optimal configurations and as edges the weighted oriented transitions between their basins of attraction. We apply the approach to the detection of communities in the optima networks produced by two different classes of instances of a hard combinatorial optimization problem: the quadratic assignment problem (QAP). We provide evidence indicating that the two problem instance classes give rise to very different configuration spaces. For the so-called real-like class, the networks possess a clear modular structure, while the optima networks belonging to the class of random uniform instances are less well partitionable into clusters. This is convincingly supported by using several statistical tests. Finally, we briefly discuss the consequences of the findings for heuristically searching the corresponding problem spaces.

  14. Scalable Spectrum Sharing Mechanism for Local Area Networks Deployment

    DEFF Research Database (Denmark)

    Da Costa, Gustavo Wagner Oliveira; Cattoni, Andrea Fabio; Kovacs, Istvan Zsolt

    2010-01-01

    /dimensioning approach. Cognitive Radio (CR) based networking methodologies are considered as the most promising solutions for such radio resource sharing problems, enabling also unlicensed/open spectrum operations. In this paper we propose and evaluate a novel protocol stack for Link Layer (LL) and radio resource......The availability on the market of powerful and lightweight mobile devices has led to a fast diffusion of mobile services for end users and the trend is shifting from voice based services to multimedia contents distribution. The current access networks are, however, able to support relatively low...... in high mobility conditions. These goals can be only achieved through the use highly Optimized Local Area (OLA) access networks, operating at low range and low power transmissions. The efficient sharing of radio resources among OLAs will be very difficult to achieve with a traditional network planning...

  15. Changes of hierarchical network in local and world stock market

    Science.gov (United States)

    Patwary, Enayet Ullah; Lee, Jong Youl; Nobi, Ashadun; Kim, Doo Hwan; Lee, Jae Woo

    2017-10-01

    We consider the cross-correlation coefficients of the daily returns in the local and global stock markets. We generate the minimal spanning tree (MST) using the correlation matrix. We observe that the MSTs change their structure from chain-like networks to star-like networks during periods of market uncertainty. We quantify the measure of the hierarchical network utilizing the value of the hierarchy measured by the hierarchical path. The hierarchy and betweenness centrality characterize the state of the market regarding the impact of crises. During crises, the non-financial company is established as the central node of the MST. However, before the crisis and during stable periods, the financial company is occupying the central node of the MST in the Korean and the U.S. stock markets. The changes in the network structure and the central node are good indicators of an upcoming crisis.

  16. The predictive power of local properties of financial networks

    Science.gov (United States)

    Caraiani, Petre

    2017-01-01

    The literature on analyzing the dynamics of financial networks has focused so far on the predictive power of global measures of networks like entropy or index cohesive force. In this paper, I show that the local network properties have similar predictive power. I focus on key network measures like average path length, average degree or cluster coefficient, and also consider the diameter and the s-metric. Using Granger causality tests, I show that some of these measures have statistically significant prediction power with respect to the dynamics of aggregate stock market. Average path length is most robust relative to the frequency of data used or specification (index or growth rate). Most measures are found to have predictive power only for monthly frequency. Further evidences that support this view are provided through a simple regression model.

  17. A local algorithm for detecting community structures in dynamic networks

    CERN Document Server

    Massaro, Emanuele; Guazzini, Andrea; Passarella, Andrea; Bagnoli, Franco

    2013-01-01

    The emergence and the global adaptation of mobile devices has influenced human interactions at the individual, community, and social levels leading to the so called Cyber-Physical World (CPW) convergence scenario [1]. One of the most important features of CPW is the possibility of exploiting information about the structure of social communities of users, that manifest through joint movement patterns and frequency of physical co-location: mobile devices of users that belong to the same social community are likely to "see" each other (and thus be able to communicate through ad hoc networking techniques) more frequently and regularly than devices outside of the community. In mobile opportunistic networks, this fact can be exploited, for example, to optimize networking operations such as forwarding and dissemination of messages. In this paper we present a novel local cognitive-inspired algorithm for revealing the structure of these dynamic social networks by exploiting information about physical encounters, logge...

  18. A New Iterated Local Search Algorithm for Solving Broadcast Scheduling Problems in Packet Radio Networks

    Directory of Open Access Journals (Sweden)

    Chih-Chiang Lin

    2010-01-01

    Full Text Available The broadcast scheduling problem (BSP in packet radio networks is a well-known NP-complete combinatorial optimization problem. The broadcast scheduling avoids packet collisions by allowing only one node transmission in each collision domain of a time division multiple access (TDMA network. It also improves the transmission utilization by assigning one transmission time slot to one or more nodes; thus, each node transmits at least once in each time frame. An optimum transmission schedule could minimize the length of a time frame while minimizing the number of idle nodes. In this paper, we propose a new iterated local search (ILS algorithm that consists of two special perturbation and local search operators to solve the BSPs. Computational experiments are applied to benchmark data sets and randomly generated problem instances. The experimental results show that our ILS approach is effective in solving the problems with only a few runtimes, even for very large networks with 2,500 nodes.

  19. Enhanced Voting based Secure Localization for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    M. B. Nirmala

    2015-11-01

    Full Text Available Development of location estimation algorithms with improvement in location precision with lower cost, less energy consumption and less hardware support has become more important for many applications in Wireless Sensor Networks (WSNs. This paper addresses the problem of secure location determination, known as secure localization in WSNs using voting based technique which gives a search region in presence of anchor nodes. From the obtained search region trilateration is applied to know the position of sensor nodes. To avoid the involvement of sensor nodes in further location estimation process, bilateration is applied. Experimental analysis shows that the maximum number of nodes can be localized and accurate location of a node can be determined efficiently with low estimation error. To avoid the attacks and involvement of malicious nodes in the localization process, we implement an improved authentication and security algorithm. Using few location reference points in the localization process reduces the communication cost. The proposed scheme also provides very good localization accuracy.

  20. Networked Computing in the 1990s.

    Science.gov (United States)

    Tesler, Lawrence G.

    1991-01-01

    The changes in the relationship between the computer and user from that of an isolated productivity tool to than of an active collaborator in the acquisition, use, and creation of information, as well as a facilitator of human interaction are discussed. The four paradigms of computing are compared. (KR)

  1. Cloud Computing in Mobile Communication Networks

    Institute of Scientific and Technical Information of China (English)

    Xinzhi Ouyang

    2011-01-01

    Cloud computing makes computing power universally available and provides flexibility in resource acquisition. It allows for scalable provision of services and more reasonable use of resources. This article considers cloud service deployment and virtualization from the perspective of mobile operators. A solution is proposed that allows mobile operators to maximize profits with minimal investment,

  2. A Comparative Study of 11 Local Health Department Organizational Networks

    Science.gov (United States)

    Merrill, Jacqueline; Keeling, Jonathan W.; Carley, Kathleen M.

    2013-01-01

    Context Although the nation’s local health departments (LHDs) share a common mission, variability in administrative structures is a barrier to identifying common, optimal management strategies. There is a gap in understanding what unifying features LHDs share as organizations that could be leveraged systematically for achieving high performance. Objective To explore sources of commonality and variability in a range of LHDs by comparing intraorganizational networks. Intervention We used organizational network analysis to document relationships between employees, tasks, knowledge, and resources within LHDs, which may exist regardless of formal administrative structure. Setting A national sample of 11 LHDs from seven states that differed in size, geographic location, and governance. Participants Relational network data were collected via an on-line survey of all employees in 11 LHDs. A total of 1 062 out of 1 239 employees responded (84% response rate). Outcome Measures Network measurements were compared using coefficient of variation. Measurements were correlated with scores from the National Public Health Performance Assessment and with LHD demographics. Rankings of tasks, knowledge, and resources were correlated across pairs of LHDs. Results We found that 11 LHDs exhibited compound organizational structures in which centralized hierarchies were coupled with distributed networks at the point of service. Local health departments were distinguished from random networks by a pattern of high centralization and clustering. Network measurements were positively associated with performance for 3 of 10 essential services (r > 0.65). Patterns in the measurements suggest how LHDs adapt to the population served. Conclusions Shared network patterns across LHDs suggest where common organizational management strategies are feasible. This evidence supports national efforts to promote uniform standards for service delivery to diverse populations. PMID:20445462

  3. Fundamentals of computational intelligence neural networks, fuzzy systems, and evolutionary computation

    CERN Document Server

    Keller, James M; Fogel, David B

    2016-01-01

    This book covers the three fundamental topics that form the basis of computational intelligence: neural networks, fuzzy systems, and evolutionary computation. The text focuses on inspiration, design, theory, and practical aspects of implementing procedures to solve real-world problems. While other books in the three fields that comprise computational intelligence are written by specialists in one discipline, this book is co-written by current former Editor-in-Chief of IEEE Transactions on Neural Networks and Learning Systems, a former Editor-in-Chief of IEEE Transactions on Fuzzy Systems, and the founding Editor-in-Chief of IEEE Transactions on Evolutionary Computation. The coverage across the three topics is both uniform and consistent in style and notation. Discusses single-layer and multilayer neural networks, radial-basi function networks, and recurrent neural networks Covers fuzzy set theory, fuzzy relations, fuzzy logic interference, fuzzy clustering and classification, fuzzy measures and fuzz...

  4. EEG Resting-State Networks: microstates' source localization.

    Science.gov (United States)

    Custo, Anna; van der Ville, Dimitri; Wells, William M; Tomescu, Ioana M; Michel, Christoph

    2017-09-22

    Using EEG to elucidate the spontaneous activation of brain resting state networks is non trivial as the signal of interest is of low amplitude and it is difficult to distinguish the underlying neural sources. Using the principles of electric field topographical analysis, it is possible to estimate the meta-stable states of the brain (i.e., the resting state topographies, so-called microstates). We estimated seven resting state topographies explaining the EEG dataset with k-means clustering (N=164, 256 electrodes). Using a method specifically designed to localize the sources of broadband EEG scalp topographies by matching sensor and source space temporal patterns, we demonstrated that we can estimate the EEG resting state networks reliably by measuring the reproducibility of our findings. After subtracting their mean from the seven EEG resting state networks, we identified seven state-specific networks. The mean map includes regions known to be densely anatomically and functionally connected (superior frontal, superior parietal, insula, and anterior cingulate cortices). While the mean map can be interpreted as a "router", cross-linking multiple functional networks, the seven state-specific resting state networks partly resemble and extend previous fMRI-based networks estimated as the hemodynamic correlates of four canonical EEG microstates.

  5. Trajectory Based Optimal Segment Computation in Road Network Databases

    DEFF Research Database (Denmark)

    Li, Xiaohui; Ceikute, Vaida; Jensen, Christian S.

    that adopt different approaches to computing the query. Algorithm AUG uses graph augmentation, and ITE uses iterative road-network partitioning. Empirical studies with real data sets demonstrate that the algorithms are capable of offering high performance in realistic settings....... that are shown empirically to be scalable. Given a road network, a set of existing facilities, and a collection of customer route traversals, an optimal segment query returns the optimal road network segment(s) for a new facility. We propose a practical framework for computing this query, where each route...

  6. Trajectory Based Optimal Segment Computation in Road Network Databases

    DEFF Research Database (Denmark)

    Li, Xiaohui; Ceikute, Vaida; Jensen, Christian S.

    2013-01-01

    that adopt different approaches to computing the query. Algorithm AUG uses graph augmentation, and ITE uses iterative road-network partitioning. Empirical studies with real data sets demonstrate that the algorithms are capable of offering high performance in realistic settings....... that are shown empirically to be scalable. Given a road network, a set of existing facilities, and a collection of customer route traversals, an optimal segment query returns the optimal road network segment(s) for a new facility. We propose a practical framework for computing this query, where each route...

  7. The very local Hubble flow: computer simulations of dynamical history

    CERN Document Server

    Chernin, A D; Valtonen, M J; Dolgachev, V P; Domozhilova, L M; Makarov, D I

    2003-01-01

    The phenomenon of the very local ($\\le3$ Mpc) Hubble flow is studied on the basis of the data of recent precision observations. A set of computer simulations is performed to trace the trajectories of the flow galaxies back in time to the epoch of the formation of the Local Group. It is found that the `initial conditions' of the flow are drastically different from the linear velocity-distance relation. The simulations enable also to recognize the major trends of the flow evolution and identify the dynamical role of universal antigravity produced by cosmic vacuum.

  8. BECUN. The Educational Computer User's Network at Battelle.

    Science.gov (United States)

    Battelle Memorial Inst., Columbus, OH.

    The Educational Computer User's Network at Battelle Columbus Laboratories is a cooperative computer center effort between a group of Ohio colleges, secondary schools, and a large research-oriented organization. This description of the program includes the historical background, program concept, data processing development, hardware and software,…

  9. Adaptive Local Information Transfer in Random Boolean Networks.

    Science.gov (United States)

    Haruna, Taichi

    2017-01-01

    Living systems such as gene regulatory networks and neuronal networks have been supposed to work close to dynamical criticality, where their information-processing ability is optimal at the whole-system level. We investigate how this global information-processing optimality is related to the local information transfer at each individual-unit level. In particular, we introduce an internal adjustment process of the local information transfer and examine whether the former can emerge from the latter. We propose an adaptive random Boolean network model in which each unit rewires its incoming arcs from other units to balance stability of its information processing based on the measurement of the local information transfer pattern. First, we show numerically that random Boolean networks can self-organize toward near dynamical criticality in our model. Second, the proposed model is analyzed by a mean-field theory. We recognize that the rewiring rule has a bootstrapping feature. The stationary indegree distribution is calculated semi-analytically and is shown to be close to dynamical criticality in a broad range of model parameter values.

  10. Recurrent Neural Network for Computing Outer Inverse.

    Science.gov (United States)

    Živković, Ivan S; Stanimirović, Predrag S; Wei, Yimin

    2016-05-01

    Two linear recurrent neural networks for generating outer inverses with prescribed range and null space are defined. Each of the proposed recurrent neural networks is based on the matrix-valued differential equation, a generalization of dynamic equations proposed earlier for the nonsingular matrix inversion, the Moore-Penrose inversion, as well as the Drazin inversion, under the condition of zero initial state. The application of the first approach is conditioned by the properties of the spectrum of a certain matrix; the second approach eliminates this drawback, though at the cost of increasing the number of matrix operations. The cases corresponding to the most common generalized inverses are defined. The conditions that ensure stability of the proposed neural network are presented. Illustrative examples present the results of numerical simulations.

  11. Internetworking satellite and local exchange networks for personal communications applications

    Science.gov (United States)

    Wolff, Richard S.; Pinck, Deborah

    1993-01-01

    The demand for personal communications services has shown unprecedented growth, and the next decade and beyond promise an era in which the needs for ubiquitous, transparent and personalized access to information will continue to expand in both scale and scope. The exchange of personalized information is growing from two-way voice to include data communications, electronic messaging and information services, image transfer, video, and interactive multimedia. The emergence of new land-based and satellite-based wireless networks illustrates the expanding scale and trend toward globalization and the need to establish new local exchange and exchange access services to meet the communications needs of people on the move. An important issue is to identify the roles that satellite networking can play in meeting these new communications needs. The unique capabilities of satellites, in providing coverage to large geographic areas, reaching widely dispersed users, for position location determination, and in offering broadcast and multicast services, can complement and extend the capabilities of terrestrial networks. As an initial step in exploring the opportunities afforded by the merger of satellite-based and land-based networks, several experiments utilizing the NASA ACTS satellite and the public switched local exchange network were undertaken to demonstrate the use of satellites in the delivery of personal communications services.

  12. Research on the Robustness of Interdependent Networks under Localized Attack

    Directory of Open Access Journals (Sweden)

    Junde Wang

    2017-06-01

    Full Text Available Critical infrastructures (CI are the cornerstone of modern society, and they are connected with each other through material, energy, or information. The robustness of interdependent CI systems under attack has been a hot topic in recent years, but previous studies mainly focused on malicious attacks or random failure. To analyze the impact of some natural disasters whose destructive force is mainly related to distance with respect to interdependent CI systems, we present a new localized attack mode considering destructive force decays with distance, and carry out simulations on several interdependent networks constructed by artificial and real world networks. Furthermore, this article analyzes the influence of coupling strength and coupling pattern on the robustness of interdependent system. The results show that dependency links between networks decrease the robustness of interdependence networks, but the robustness under failure probability degradation is not vulnerable like that under malicious attack or random failure. In addition, the coupling preference has little effect on the robustness of interdependent networks under the new localized attack strategy; when the average degree of subnetworks is large, the same conclusion can be obtained for the coupling strength.

  13. Active system area networks for data intensive computations. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-04-01

    The goal of the Active System Area Networks (ASAN) project is to develop hardware and software technologies for the implementation of active system area networks (ASANs). The use of the term ''active'' refers to the ability of the network interfaces to perform application-specific as well as system level computations in addition to their traditional role of data transfer. This project adopts the view that the network infrastructure should be an active computational entity capable of supporting certain classes of computations that would otherwise be performed on the host CPUs. The result is a unique network-wide programming model where computations are dynamically placed within the host CPUs or the NIs depending upon the quality of service demands and network/CPU resource availability. The projects seeks to demonstrate that such an approach is a better match for data intensive network-based applications and that the advent of low-cost powerful embedded processors and configurable hardware makes such an approach economically viable and desirable.

  14. Optical interconnection networks for high-performance computing systems.

    Science.gov (United States)

    Biberman, Aleksandr; Bergman, Keren

    2012-04-01

    Enabled by silicon photonic technology, optical interconnection networks have the potential to be a key disruptive technology in computing and communication industries. The enduring pursuit of performance gains in computing, combined with stringent power constraints, has fostered the ever-growing computational parallelism associated with chip multiprocessors, memory systems, high-performance computing systems and data centers. Sustaining these parallelism growths introduces unique challenges for on- and off-chip communications, shifting the focus toward novel and fundamentally different communication approaches. Chip-scale photonic interconnection networks, enabled by high-performance silicon photonic devices, offer unprecedented bandwidth scalability with reduced power consumption. We demonstrate that the silicon photonic platforms have already produced all the high-performance photonic devices required to realize these types of networks. Through extensive empirical characterization in much of our work, we demonstrate such feasibility of waveguides, modulators, switches and photodetectors. We also demonstrate systems that simultaneously combine many functionalities to achieve more complex building blocks. We propose novel silicon photonic devices, subsystems, network topologies and architectures to enable unprecedented performance of these photonic interconnection networks. Furthermore, the advantages of photonic interconnection networks extend far beyond the chip, offering advanced communication environments for memory systems, high-performance computing systems, and data centers.

  15. Recurrent kernel machines: computing with infinite echo state networks.

    Science.gov (United States)

    Hermans, Michiel; Schrauwen, Benjamin

    2012-01-01

    Echo state networks (ESNs) are large, random recurrent neural networks with a single trained linear readout layer. Despite the untrained nature of the recurrent weights, they are capable of performing universal computations on temporal input data, which makes them interesting for both theoretical research and practical applications. The key to their success lies in the fact that the network computes a broad set of nonlinear, spatiotemporal mappings of the input data, on which linear regression or classification can easily be performed. One could consider the reservoir as a spatiotemporal kernel, in which the mapping to a high-dimensional space is computed explicitly. In this letter, we build on this idea and extend the concept of ESNs to infinite-sized recurrent neural networks, which can be considered recursive kernels that subsequently can be used to create recursive support vector machines. We present the theoretical framework, provide several practical examples of recursive kernels, and apply them to typical temporal tasks.

  16. 1st International Conference on Signal, Networks, Computing, and Systems

    CERN Document Server

    Mohapatra, Durga; Nagar, Atulya; Sahoo, Manmath

    2016-01-01

    The book is a collection of high-quality peer-reviewed research papers presented in the first International Conference on Signal, Networks, Computing, and Systems (ICSNCS 2016) held at Jawaharlal Nehru University, New Delhi, India during February 25–27, 2016. The book is organized in to two volumes and primarily focuses on theory and applications in the broad areas of communication technology, computer science and information security. The book aims to bring together the latest scientific research works of academic scientists, professors, research scholars and students in the areas of signal, networks, computing and systems detailing the practical challenges encountered and the solutions adopted.

  17. Console Networks for Major Computer Systems

    Energy Technology Data Exchange (ETDEWEB)

    Ophir, D; Shepherd, B; Spinrad, R J; Stonehill, D

    1966-07-22

    A concept for interactive time-sharing of a major computer system is developed in which satellite computers mediate between the central computing complex and the various individual user terminals. These techniques allow the development of a satellite system substantially independent of the details of the central computer and its operating system. Although the user terminals' roles may be rich and varied, the demands on the central facility are merely those of a tape drive or similar batched information transfer device. The particular system under development provides service for eleven visual display and communication consoles, sixteen general purpose, low rate data sources, and up to thirty-one typewriters. Each visual display provides a flicker-free image of up to 4000 alphanumeric characters or tens of thousands of points by employing a swept raster picture generating technique directly compatible with that of commercial television. Users communicate either by typewriter or a manually positioned light pointer.

  18. Electromagnetic field computation by network methods

    CERN Document Server

    Felsen, Leopold B; Russer, Peter

    2009-01-01

    This monograph proposes a systematic and rigorous treatment of electromagnetic field representations in complex structures. The book presents new strong models by combining important computational methods. This is the last book of the late Leopold Felsen.

  19. CX: A Scalable, Robust Network for Parallel Computing

    Directory of Open Access Journals (Sweden)

    Peter Cappello

    2002-01-01

    Full Text Available CX, a network-based computational exchange, is presented. The system's design integrates variations of ideas from other researchers, such as work stealing, non-blocking tasks, eager scheduling, and space-based coordination. The object-oriented API is simple, compact, and cleanly separates application logic from the logic that supports interprocess communication and fault tolerance. Computations, of course, run to completion in the presence of computational hosts that join and leave the ongoing computation. Such hosts, or producers, use task caching and prefetching to overlap computation with interprocessor communication. To break a potential task server bottleneck, a network of task servers is presented. Even though task servers are envisioned as reliable, the self-organizing, scalable network of n- servers, described as a sibling-connected height-balanced fat tree, tolerates a sequence of n-1 server failures. Tasks are distributed throughout the server network via a simple "diffusion" process. CX is intended as a test bed for research on automated silent auctions, reputation services, authentication services, and bonding services. CX also provides a test bed for algorithm research into network-based parallel computation.

  20. Localized Algorithm for Channel Assignment in Cognitive Radio Networks

    Directory of Open Access Journals (Sweden)

    Harpreet Kaur

    2015-12-01

    Full Text Available Cognitive Radio has been emerged as a revolutionary solution to migrate the current shortage of spectrum allocation in wireless networks. In this paper, an improved localized channel allocation algorithm based on channel weight is proposed. A factor of channel stability is introduced based on link environment, which efficiently assigns the best channels to the links. Based on the framework, a conflict resolution strategy is used to make the scheme adaptable to different network conditions. Calculations indicate that this algorithm can reduce the conflicts, increase the delivery rate and link assignment rate compared with the basic channel assignment algorithm.

  1. The Role of Networks in Cloud Computing

    Science.gov (United States)

    Lin, Geng; Devine, Mac

    The confluence of technology advancements and business developments in Broadband Internet, Web services, computing systems, and application software over the past decade has created a perfect storm for cloud computing. The "cloud model" of delivering and consuming IT functions as services is poised to fundamentally transform the IT industry and rebalance the inter-relationships among end users, enterprise IT, software companies, and the service providers in the IT ecosystem (Armbrust et al., 2009; Lin, Fu, Zhu, & Dasmalchi, 2009).

  2. Applying Web Services with Mobile Agents for Computer Network Management

    Directory of Open Access Journals (Sweden)

    Mydhili K.Nair

    2011-03-01

    Full Text Available The exponential rise in complexity of the underlying network elements of a computer network makes itsManagement an intricate, multifaceted and complex problem to solve. With every passing decade, newtechnologies are developed to ease this problem of Network Management. The last decade of the premillenniumera saw the peak of CORBA and Mobile Agent Based implementations, while the first decadeof post millennium saw the emergence of Web Services. All of these technologies evolved as independent,self-contained implementation streams. There is a genuine dearth in finding authentic research outcomeswhere quantifiable, measureable benefits of convergence of these technologies applied to NetworkManagement are put forth. This paper aims to fill this research gap. Here we put forth the experimentalresults obtained of a framework we developed in-house for Network Management that combined twoseemingly divergent distributed computing technologies, namely, Web Services and Mobile Agents.

  3. Coherent Computing with Injection-Locked Laser Network

    Science.gov (United States)

    Utsunomiya, S.; Wen, K.; Takata, K.; Tamate, S.; Yamamoto, Yoshihisa

    Combinatorial optimization problems are ubiquitous in our modern life. The classic examples include the protein folding in biology and medicine, the frequency assignment in wireless communications, traffic control and routing in air and on surface, microprocessor circuit design, computer vision and graph cut in machine learning, and social network control. They often belong to NP, NP-complete and NP-hard classes, for which modern digital computers and future quantum computers cannot find solutions efficiently, i.e. in polynomial time [1].

  4. Predictive Control of Networked Multiagent Systems via Cloud Computing.

    Science.gov (United States)

    Liu, Guo-Ping

    2017-01-18

    This paper studies the design and analysis of networked multiagent predictive control systems via cloud computing. A cloud predictive control scheme for networked multiagent systems (NMASs) is proposed to achieve consensus and stability simultaneously and to compensate for network delays actively. The design of the cloud predictive controller for NMASs is detailed. The analysis of the cloud predictive control scheme gives the necessary and sufficient conditions of stability and consensus of closed-loop networked multiagent control systems. The proposed scheme is verified to characterize the dynamical behavior and control performance of NMASs through simulations. The outcome provides a foundation for the development of cooperative and coordinative control of NMASs and its applications.

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

    Science.gov (United States)

    Cui, Zhenqian

    1999-01-01

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

  6. SCLpredT: Ab initio and homology-based prediction of subcellular localization by N-to-1 neural networks

    OpenAIRE

    Adelfio, Alessandro; Volpato, Viola; Pollastri, Gianluca

    2013-01-01

    Abstract The prediction of protein subcellular localization is a important step towards the prediction of protein function, and considerable effort has gone over the last decade into the development of computational predictors of protein localization. In this article we design a new predictor of protein subcellular localization, based on a Machine Learning model (N-to-1 Neural Networks) which we have recently developed. This system, in three versions specialised, respectively, on Plants, Fung...

  7. Research Activity in Computational Physics utilizing High Performance Computing: Co-authorship Network Analysis

    Science.gov (United States)

    Ahn, Sul-Ah; Jung, Youngim

    2016-10-01

    The research activities of the computational physicists utilizing high performance computing are analyzed by bibliometirc approaches. This study aims at providing the computational physicists utilizing high-performance computing and policy planners with useful bibliometric results for an assessment of research activities. In order to achieve this purpose, we carried out a co-authorship network analysis of journal articles to assess the research activities of researchers for high-performance computational physics as a case study. For this study, we used journal articles of the Scopus database from Elsevier covering the time period of 2004-2013. We extracted the author rank in the physics field utilizing high-performance computing by the number of papers published during ten years from 2004. Finally, we drew the co-authorship network for 45 top-authors and their coauthors, and described some features of the co-authorship network in relation to the author rank. Suggestions for further studies are discussed.

  8. A new framework to integrate wireless sensor networks with cloud computing

    Science.gov (United States)

    Shah, Sajjad Hussain; Khan, Fazle Kabeer; Ali, Wajid; Khan, Jamshed

    Wireless sensors networks have several applications of their own. These applications can further enhanced by integrating a local wireless sensor network to internet, which can be used in real time applications where the results of sensors are stored on the cloud. We propose an architecture that integrates a wireless sensor network to the internet using cloud technology. The resultant system is proved to be reliable, available and extensible. In this paper a new framework is proposed for WSN integration with Cloud computing model, existing WSN will be connected to the proposed framework. Three deployment layer are used to serve user request (IaaS, PaaS, SaaS) either from the library which is made from data collected from data centric DC by WSN periodically. The integration controller unit of the proposed framework integrates the sensor network and cloud computing technology which offers reliability, availability and extensibility.

  9. Local authorities facing flood related networks failures in France

    Directory of Open Access Journals (Sweden)

    Gallet Violette

    2016-01-01

    Full Text Available Network critical infrastructures have become vital to keep our societies running in every-day situations, but also during crisis and recovery. Involving many stakeholders at different scales, they form a complex system that can be easily disturbed by internal or external events, because then all the dependencies that allow to optimizing their working become flaws that help failures to spread beyond the flooded area and from one network to another. Thus every flood reminds us how vulnerable infrastructures are and how much it costs when they fail. But whereas it isn’t so difficult to adapt new urban development, what about all the existing and exposed infrastructures? CEPRI carried out research on encountered difficulties and good practices to understand the situation and consider improvement opportunities. We worked out three steps to a better territory resilience to flood. First, get a better knowledge of networks. Then, as far as possible, reduce networks vulnerability. Finally, as risks of network failures always remain, get prepared to cope with disruptions! CEPRI gathered many experiences to illustrate and strengthen its work, which aims at helping local authorities to reduce their vulnerability to flood and related networks failures.

  10. A compute unified system architecture for graphics clusters incorporating data locality.

    Science.gov (United States)

    Müller, Christoph; Frey, Steffen; Strengert, Magnus; Dachsbacher, Carsten; Ertl, Thomas

    2009-01-01

    We present a development environment for distributed GPU computing targeted for multi-GPU systems, as well as graphics clusters. Our system is based on CUDA and logically extends its parallel programming model for graphics processors to higher levels of parallelism, namely, the PCI bus and network interconnects. While the extended API mimics the full function set of current graphics hardware-including the concept of global memory-on all distribution layers, the underlying communication mechanisms are handled transparently for the application developer. To allow for high scalability, in particular for network-interconnected environments, we introduce an automatic GPU-accelerated scheduling mechanism that is aware of data locality. This way, the overall amount of transmitted data can be heavily reduced, which leads to better GPU utilization and faster execution. We evaluate the performance and scalability of our system for bus and especially network-level parallelism on typical multi-GPU systems and graphics clusters.

  11. Wlan-Based Indoor Localization Using Neural Networks

    Science.gov (United States)

    Saleem, Fasiha; Wyne, Shurjeel

    2016-07-01

    Wireless indoor localization has generated recent research interest due to its numerous applications. This work investigates Wi-Fi based indoor localization using two variants of the fingerprinting approach. Specifically, we study the application of an artificial neural network (ANN) for implementing the fingerprinting approach and compare its localization performance with a probabilistic fingerprinting method that is based on maximum likelihood estimation (MLE) of the user location. We incorporate spatial correlation of fading into our investigations, which is often neglected in simulation studies and leads to erroneous location estimates. The localization performance is quantified in terms of accuracy, precision, robustness, and complexity. Multiple methods for handling the case of missing APs in online stage are investigated. Our results indicate that ANN-based fingerprinting outperforms the probabilistic approach for all performance metrics considered in this work.

  12. A local fuzzy method based on “p-strong” community for detecting communities in networks

    Science.gov (United States)

    Yi, Shen; Gang, Ren; Yang, Liu; Jia-Li, Xu

    2016-06-01

    In this paper, we propose a local fuzzy method based on the idea of “p-strong” community to detect the disjoint and overlapping communities in networks. In the method, a refined agglomeration rule is designed for agglomerating nodes into local communities, and the overlapping nodes are detected based on the idea of making each community strong. We propose a contribution coefficient to measure the contribution of an overlapping node to each of its belonging communities, and the fuzzy coefficients of the overlapping node can be obtained by normalizing the to all its belonging communities. The running time of our method is analyzed and varies linearly with network size. We investigate our method on the computer-generated networks and real networks. The testing results indicate that the accuracy of our method in detecting disjoint communities is higher than those of the existing local methods and our method is efficient for detecting the overlapping nodes with fuzzy coefficients. Furthermore, the local optimizing scheme used in our method allows us to partly solve the resolution problem of the global modularity. Project supported by the National Natural Science Foundation of China (Grant Nos. 51278101 and 51578149), the Science and Technology Program of Ministry of Transport of China (Grant No. 2015318J33080), the Jiangsu Provincial Post-doctoral Science Foundation, China (Grant No. 1501046B), and the Fundamental Research Funds for the Central Universities, China (Grant No. Y0201500219).

  13. Local synchronization of chaotic neural networks with sampled-data and saturating actuators.

    Science.gov (United States)

    Wu, Zheng-Guang; Shi, Peng; Su, Hongye; Chu, Jian

    2014-12-01

    This paper investigates the problem of local synchronization of chaotic neural networks with sampled-data and actuator saturation. A new time-dependent Lyapunov functional is proposed for the synchronization error systems. The advantage of the constructed Lyapunov functional lies in the fact that it is positive definite at sampling times but not necessarily between sampling times, and makes full use of the available information about the actual sampling pattern. A local stability condition of the synchronization error systems is derived, based on which a sampled-data controller with respect to the actuator saturation is designed to ensure that the master neural networks and slave neural networks are locally asymptotically synchronous. Two optimization problems are provided to compute the desired sampled-data controller with the aim of enlarging the set of admissible initial conditions or the admissible sampling upper bound ensuring the local synchronization of the considered chaotic neural networks. A numerical example is used to demonstrate the effectiveness of the proposed design technique.

  14. Multiple core computer processor with globally-accessible local memories

    Energy Technology Data Exchange (ETDEWEB)

    Shalf, John; Donofrio, David; Oliker, Leonid

    2016-09-20

    A multi-core computer processor including a plurality of processor cores interconnected in a Network-on-Chip (NoC) architecture, a plurality of caches, each of the plurality of caches being associated with one and only one of the plurality of processor cores, and a plurality of memories, each of the plurality of memories being associated with a different set of at least one of the plurality of processor cores and each of the plurality of memories being configured to be visible in a global memory address space such that the plurality of memories are visible to two or more of the plurality of processor cores.

  15. Real time network traffic monitoring for wireless local area networks based on compressed sensing

    Science.gov (United States)

    Balouchestani, Mohammadreza

    2017-05-01

    A wireless local area network (WLAN) is an important type of wireless networks which connotes different wireless nodes in a local area network. WLANs suffer from important problems such as network load balancing, large amount of energy, and load of sampling. This paper presents a new networking traffic approach based on Compressed Sensing (CS) for improving the quality of WLANs. The proposed architecture allows reducing Data Delay Probability (DDP) to 15%, which is a good record for WLANs. The proposed architecture is increased Data Throughput (DT) to 22 % and Signal to Noise (S/N) ratio to 17 %, which provide a good background for establishing high qualified local area networks. This architecture enables continuous data acquisition and compression of WLAN's signals that are suitable for a variety of other wireless networking applications. At the transmitter side of each wireless node, an analog-CS framework is applied at the sensing step before analog to digital converter in order to generate the compressed version of the input signal. At the receiver side of wireless node, a reconstruction algorithm is applied in order to reconstruct the original signals from the compressed signals with high probability and enough accuracy. The proposed algorithm out-performs existing algorithms by achieving a good level of Quality of Service (QoS). This ability allows reducing 15 % of Bit Error Rate (BER) at each wireless node.

  16. Fault Localization Analysis Based on Deep Neural Network

    Directory of Open Access Journals (Sweden)

    Wei Zheng

    2016-01-01

    Full Text Available With software’s increasing scale and complexity, software failure is inevitable. To date, although many kinds of software fault localization methods have been proposed and have had respective achievements, they also have limitations. In particular, for fault localization techniques based on machine learning, the models available in literatures are all shallow architecture algorithms. Having shortcomings like the restricted ability to express complex functions under limited amount of sample data and restricted generalization ability for intricate problems, the faults cannot be analyzed accurately via those methods. To that end, we propose a fault localization method based on deep neural network (DNN. This approach is capable of achieving the complex function approximation and attaining distributed representation for input data by learning a deep nonlinear network structure. It also shows a strong capability of learning representation from a small sized training dataset. Our DNN-based model is trained utilizing the coverage data and the results of test cases as input and we further locate the faults by testing the trained model using the virtual test suite. This paper conducts experiments on the Siemens suite and Space program. The results demonstrate that our DNN-based fault localization technique outperforms other fault localization methods like BPNN, Tarantula, and so forth.

  17. INTERPLANETARY NETWORK LOCALIZATIONS OF KONUS SHORT GAMMA-RAY BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Pal' shin, V. D.; Svinkin, D. S.; Aptekar, R. L.; Golenetskii, S. V.; Frederiks, D. D.; Mazets, E. P.; Oleynik, P. P.; Ulanov, M. V. [Ioffe Physical Technical Institute, St. Petersburg, 194021 (Russian Federation); Hurley, K. [Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720-7450 (United States); Cline, T.; Trombka, J.; McClanahan, T. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Mitrofanov, I. G.; Golovin, D. V.; Kozyrev, A. S.; Litvak, M. L.; Sanin, A. B. [Space Research Institute, 84/32, Profsoyuznaya, Moscow 117997 (Russian Federation); Boynton, W.; Fellows, C.; Harshman, K., E-mail: val@mail.ioffe.ru [Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721 (United States); and others

    2013-08-15

    Between the launch of the Global Geospace Science Wind spacecraft in 1994 November and the end of 2010, the Konus-Wind experiment detected 296 short-duration gamma-ray bursts (including 23 bursts which can be classified as short bursts with extended emission). During this period, the Interplanetary Network (IPN) consisted of up to 11 spacecraft, and using triangulation, the localizations of 271 bursts were obtained. We present the most comprehensive IPN localization data on these events. The short burst detection rate, {approx}18 yr{sup -1}, exceeds that of many individual experiments.

  18. Net Locality Why Location Matters in a Networked World

    CERN Document Server

    Gordon, Eric

    2011-01-01

    The first book to provide an introduction to the new theory of Net Locality and the profound effect on individuals and societies when everything is located or locatable. Describes net locality as an emerging form of location awareness central to all aspects of digital media, from mobile phones, to Google Maps, to location-based social networks and games, such as Foursquare and facebook.Warns of the threats these technologies, such as data surveillance, present to our sense of privacy, while also outlining the opportunities for pro-social developments.Provides a theory of the web in the context

  19. Associative Networks on a Massively Parallel Computer.

    Science.gov (United States)

    1985-10-01

    19 4.12 The Language Definition ....... ............... 21 4.1.3 Specialized Procedures and Functions... definition we give of associative networks eliminates words and meanings altogether in favor of numbers. It is assumed to be a function of a higher... lgbt (as a group of numbers, in this case), but this only leads to sensible queries when a statistical function is applied: "What is the largest salary

  20. Nonlinear system identification with global and local soft computing methods

    Energy Technology Data Exchange (ETDEWEB)

    Runkler, T.A. [Siemens AG, Muenchen (Germany). Zentralabt. Technik Information und Kommunikation

    2000-10-01

    An important step in the design of control systems is system identification. Data driven system identification finds functional models for the system's input output behavior. Regression methods are simple and effective, but may cause overshoots for complicated characteristics. Neural network approaches such as the multilayer perceptron yield very accurate models, but are black box approaches which leads to problems in system and stability analysis. In contrast to these global modeling methods crisp and fuzzy rule bases represent local models that can be extracted from data by clustering methods. Depending on the type and number of models different degrees of model accuracy can be achieved. (orig.)

  1. Multiplex networks in metropolitan areas: generic features and local effects

    CERN Document Server

    Strano, Emanuele; Dobson, Simon; Barthelemy, Marc

    2015-01-01

    Most large cities are spanned by more than one transportation system. These different modes of transport have usually been studied separately: it is however important to understand the impact on urban systems of the coupling between them and we report in this paper an empirical analysis of the coupling between the street network and the subway for the two large metropolitan areas of London and New York. We observe a similar behaviour for network quantities related to quickest paths suggesting the existence of generic mechanisms operating beyond the local peculiarities of the specific cities studied. An analysis of the betweenness centrality distribution shows that the introduction of underground networks operate as a decentralising force creating congestions in places located at the end of underground lines. Also, we find that increasing the speed of subways is not always beneficial and may lead to unwanted uneven spatial distributions of accessibility. In fact, for London -- but not for New York -- there is ...

  2. Local clustering in scale-free networks with hidden variables.

    Science.gov (United States)

    van der Hofstad, Remco; Janssen, A J E M; van Leeuwaarden, Johan S H; Stegehuis, Clara

    2017-02-01

    We investigate the presence of triangles in a class of correlated random graphs in which hidden variables determine the pairwise connections between vertices. The class rules out self-loops and multiple edges. We focus on the regime where the hidden variables follow a power law with exponent τ∈(2,3), so that the degrees have infinite variance. The natural cutoff h_{c} characterizes the largest degrees in the hidden variable models, and a structural cutoff h_{s} introduces negative degree correlations (disassortative mixing) due to the infinite-variance degrees. We show that local clustering decreases with the hidden variable (or degree). We also determine how the average clustering coefficient C scales with the network size N, as a function of h_{s} and h_{c}. For scale-free networks with exponent 2vanish only for networks as large as N=10^{9}.

  3. Experimental violation of local causality in a quantum network

    Science.gov (United States)

    Carvacho, Gonzalo; Andreoli, Francesco; Santodonato, Luca; Bentivegna, Marco; Chaves, Rafael; Sciarrino, Fabio

    2017-03-01

    Bell's theorem plays a crucial role in quantum information processing and thus several experimental investigations of Bell inequalities violations have been carried out over the years. Despite their fundamental relevance, however, previous experiments did not consider an ingredient of relevance for quantum networks: the fact that correlations between distant parties are mediated by several, typically independent sources. Here, using a photonic setup, we investigate a quantum network consisting of three spatially separated nodes whose correlations are mediated by two distinct sources. This scenario allows for the emergence of the so-called non-bilocal correlations, incompatible with any local model involving two independent hidden variables. We experimentally witness the emergence of this kind of quantum correlations by violating a Bell-like inequality under the fair-sampling assumption. Our results provide a proof-of-principle experiment of generalizations of Bell's theorem for networks, which could represent a potential resource for quantum communication protocols.

  4. A Unifying Framework for Local Throughput in Wireless Networks

    CERN Document Server

    Pinto, Pedro C

    2010-01-01

    With the increased competition for the electromagnetic spectrum, it is important to characterize the impact of interference in the performance of a wireless network, which is traditionally measured by its throughput. This paper presents a unifying framework for characterizing the local throughput in wireless networks. We first analyze the throughput of a probe link from a connectivity perspective, in which a packet is successfully received if it does not collide with other packets from nodes within its reach (called the audible interferers). We then characterize the throughput from a signal-to-interference-plus-noise ratio (SINR) perspective, in which a packet is successfully received if the SINR exceeds some threshold, considering the interference from all emitting nodes in the network. Our main contribution is to generalize and unify various results scattered throughout the literature. In particular, the proposed framework encompasses arbitrary wireless propagation effects (e.g, Nakagami-m fading, Rician fa...

  5. Experimental violation of local causality in a quantum network.

    Science.gov (United States)

    Carvacho, Gonzalo; Andreoli, Francesco; Santodonato, Luca; Bentivegna, Marco; Chaves, Rafael; Sciarrino, Fabio

    2017-03-16

    Bell's theorem plays a crucial role in quantum information processing and thus several experimental investigations of Bell inequalities violations have been carried out over the years. Despite their fundamental relevance, however, previous experiments did not consider an ingredient of relevance for quantum networks: the fact that correlations between distant parties are mediated by several, typically independent sources. Here, using a photonic setup, we investigate a quantum network consisting of three spatially separated nodes whose correlations are mediated by two distinct sources. This scenario allows for the emergence of the so-called non-bilocal correlations, incompatible with any local model involving two independent hidden variables. We experimentally witness the emergence of this kind of quantum correlations by violating a Bell-like inequality under the fair-sampling assumption. Our results provide a proof-of-principle experiment of generalizations of Bell's theorem for networks, which could represent a potential resource for quantum communication protocols.

  6. A Novel Trusted Computing Model for Network Security Authentication

    Directory of Open Access Journals (Sweden)

    Ling Xing

    2014-02-01

    Full Text Available Network information poses great threats from malicious attacks due to the openness and virtuality of network structure. Traditional methods to ensure infor- mation security may fail when both integrity and source authentication for information are required. Based on the security of data broadcast channel, a novel Trusted Com- puting Model (TCM of network security authentication is proposed to enhance the security of network information. In this model, a method of Uniform content locator security Digital Certificate (UDC, which is capable of fully and uniquely index network information, is developed. Standard of MPEG-2 Transport Streams (TS is adopted to pack UDC data. Additionally, a UDC hashing algorithm (UHA512 is designed to compute the integrity and security of data infor- mation . Experimental results show that the proposed model is feasible and effective to network security authentication. 

  7. FY 1999 Blue Book: Computing, Information, and Communications: Networked Computing for the 21st Century

    Data.gov (United States)

    Networking and Information Technology Research and Development, Executive Office of the President — U.S.research and development R and D in computing, communications, and information technologies has enabled unprecedented scientific and engineering advances,...

  8. Critical phenomena in communication/computation networks with various topologies and suboptimal to optimal resource allocation

    Science.gov (United States)

    Cogoni, Marco; Busonera, Giovanni; Anedda, Paolo; Zanetti, Gianluigi

    2015-01-01

    We generalize previous studies on critical phenomena in communication networks [1,2] by adding computational capabilities to the nodes. In our model, a set of tasks with random origin, destination and computational structure is distributed on a computational network, modeled as a graph. By varying the temperature of a Metropolis Montecarlo, we explore the global latency for an optimal to suboptimal resource assignment at a given time instant. By computing the two-point correlation function for the local overload, we study the behavior of the correlation distance (both for links and nodes) while approaching the congested phase: a transition from peaked to spread g(r) is seen above a critical (Montecarlo) temperature Tc. The average latency trend of the system is predicted by averaging over several network traffic realizations while maintaining a spatially detailed information for each node: a sharp decrease of performance is found over Tc independently of the workload. The globally optimized computational resource allocation and network routing defines a baseline for a future comparison of the transition behavior with respect to existing routing strategies [3,4] for different network topologies.

  9. Developing a Micropayments System in Local Area Networks

    Directory of Open Access Journals (Sweden)

    Cristian GEORGESCU

    2011-11-01

    Full Text Available Starting from the solution of aggregating micropayments in a local area network that operates with reduced costs, with simple and easy to use equipments, with security procedures that are not so complicated, based on the rapport between the cost of fraud and the expected value obtained through fraud, a first stage of developing this system has been accomplished and materialized in the analysis stage by using some of the diagrams put to use by UML.

  10. Development of Computer Science Disciplines - A Social Network Analysis Approach

    CERN Document Server

    Pham, Manh Cuong; Jarke, Matthias

    2011-01-01

    In contrast to many other scientific disciplines, computer science considers conference publications. Conferences have the advantage of providing fast publication of papers and of bringing researchers together to present and discuss the paper with peers. Previous work on knowledge mapping focused on the map of all sciences or a particular domain based on ISI published JCR (Journal Citation Report). Although this data covers most of important journals, it lacks computer science conference and workshop proceedings. That results in an imprecise and incomplete analysis of the computer science knowledge. This paper presents an analysis on the computer science knowledge network constructed from all types of publications, aiming at providing a complete view of computer science research. Based on the combination of two important digital libraries (DBLP and CiteSeerX), we study the knowledge network created at journal/conference level using citation linkage, to identify the development of sub-disciplines. We investiga...

  11. Developing Computer Network Based on EIGRP Performance Comparison and OSPF

    Directory of Open Access Journals (Sweden)

    Lalu Zazuli Azhar Mardedi

    2015-09-01

    Full Text Available One of the computer network systems technologies that are growing rapidly at this time is internet. In building the networks, a routing mechanism is needed to integrate the entire computer with a high degree of flexibility. Routing is a major part in giving a performance to the network. With many existing routing protocols, network administrators need a reference comparison of the performance of each type of the routing protocol. One such routing is Enhanced Interior Gateway Routing Protocol (EIGRP and Open Shortest Path First (OSPF. This paper only focuses on the performance of both the routing protocol on the network topology hybrid. Network services existing internet access speeds average of 8.0 KB/sec and 2 MB bandwidth. A backbone network is used by two academies, they are Academy of Information Management and Computer (AIMC and Academy of Secretary and Management (ASM, with 2041 clients and it caused slow internet access. To solve the problems, the analysis and comparison of performance between the Enhanced Interior Gateway Routing Protocol (EIGRP and Open Shortest Path First (OSPF will be applied. Simulation software Cisco Packet Tracer 6.0.1 is used to get the value and to verify the results of its use.

  12. A computational model for cancer growth by using complex networks

    Science.gov (United States)

    Galvão, Viviane; Miranda, José G. V.

    2008-09-01

    In this work we propose a computational model to investigate the proliferation of cancerous cell by using complex networks. In our model the network represents the structure of available space in the cancer propagation. The computational scheme considers a cancerous cell randomly included in the complex network. When the system evolves the cells can assume three states: proliferative, non-proliferative, and necrotic. Our results were compared with experimental data obtained from three human lung carcinoma cell lines. The computational simulations show that the cancerous cells have a Gompertzian growth. Also, our model simulates the formation of necrosis, increase of density, and resources diffusion to regions of lower nutrient concentration. We obtain that the cancer growth is very similar in random and small-world networks. On the other hand, the topological structure of the small-world network is more affected. The scale-free network has the largest rates of cancer growth due to hub formation. Finally, our results indicate that for different average degrees the rate of cancer growth is related to the available space in the network.

  13. Functional brain networks develop from a "local to distributed" organization.

    Directory of Open Access Journals (Sweden)

    Damien A Fair

    2009-05-01

    Full Text Available The mature human brain is organized into a collection of specialized functional networks that flexibly interact to support various cognitive functions. Studies of development often attempt to identify the organizing principles that guide the maturation of these functional networks. In this report, we combine resting state functional connectivity MRI (rs-fcMRI, graph analysis, community detection, and spring-embedding visualization techniques to analyze four separate networks defined in earlier studies. As we have previously reported, we find, across development, a trend toward 'segregation' (a general decrease in correlation strength between regions close in anatomical space and 'integration' (an increased correlation strength between selected regions distant in space. The generalization of these earlier trends across multiple networks suggests that this is a general developmental principle for changes in functional connectivity that would extend to large-scale graph theoretic analyses of large-scale brain networks. Communities in children are predominantly arranged by anatomical proximity, while communities in adults predominantly reflect functional relationships, as defined from adult fMRI studies. In sum, over development, the organization of multiple functional networks shifts from a local anatomical emphasis in children to a more "distributed" architecture in young adults. We argue that this "local to distributed" developmental characterization has important implications for understanding the development of neural systems underlying cognition. Further, graph metrics (e.g., clustering coefficients and average path lengths are similar in child and adult graphs, with both showing "small-world"-like properties, while community detection by modularity optimization reveals stable communities within the graphs that are clearly different between young children and young adults. These observations suggest that early school age children and adults

  14. Local area networking in a radio quiet environment

    Science.gov (United States)

    Childers, Edwin L.; Hunt, Gareth; Brandt, Joseph J.

    2002-11-01

    The Green Bank facility of the National Radio Astronomy Observatory is spread out over 2,700 acres in the Allegheny Mountains of West Virginia. Good communication has always been needed between the radio telescopes and the control buildings. The National Radio Quiet Zone helps protect the Green Bank site from radio transmissions that interfere with the astronomical signals. Due to stringent Radio Frequency Interference (RFI) requirements, a fiber optic communication system was used for Ethernet transmissions on the site and coaxial cable within the buildings. With the need for higher speed communications, the entire network has been upgraded to use optical fiber with modern Ethernet switches. As with most modern equipment, the implementation of the control of the newly deployed Green Bank Telescope (GBT) depends heavily on TCP/IP. In order to protect the GBT from the commodity Internet, the GBT uses a non-routable network. Communication between the control building Local Area Network (LAN) and the GBT is implemented using a Virtual LAN (VLAN). This configuration will be extended to achieve isolation between trusted local user systems, the GBT, and other Internet users. Legitimate access to the site, for example by remote observers, is likely to be implemented using a virtual private network (VPN).

  15. Reputation-Based Secure Sensor Localization in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Jingsha He

    2014-01-01

    Full Text Available Location information of sensor nodes in wireless sensor networks (WSNs is very important, for it makes information that is collected and reported by the sensor nodes spatially meaningful for applications. Since most current sensor localization schemes rely on location information that is provided by beacon nodes for the regular sensor nodes to locate themselves, the accuracy of localization depends on the accuracy of location information from the beacon nodes. Therefore, the security and reliability of the beacon nodes become critical in the localization of regular sensor nodes. In this paper, we propose a reputation-based security scheme for sensor localization to improve the security and the accuracy of sensor localization in hostile or untrusted environments. In our proposed scheme, the reputation of each beacon node is evaluated based on a reputation evaluation model so that regular sensor nodes can get credible location information from highly reputable beacon nodes to accomplish localization. We also perform a set of simulation experiments to demonstrate the effectiveness of the proposed reputation-based security scheme. And our simulation results show that the proposed security scheme can enhance the security and, hence, improve the accuracy of sensor localization in hostile or untrusted environments.

  16. Towards Optimal Event Detection and Localization in Acyclic Flow Networks

    KAUST Repository

    Agumbe Suresh, Mahima

    2012-01-03

    Acyclic flow networks, present in many infrastructures of national importance (e.g., oil & gas and water distribution systems), have been attracting immense research interest. Existing solutions for detecting and locating attacks against these infrastructures, have been proven costly and imprecise, especially when dealing with large scale distribution systems. In this paper, to the best of our knowledge for the first time, we investigate how mobile sensor networks can be used for optimal event detection and localization in acyclic flow networks. Sensor nodes move along the edges of the network and detect events (i.e., attacks) and proximity to beacon nodes with known placement in the network. We formulate the problem of minimizing the cost of monitoring infrastructure (i.e., minimizing the number of sensor and beacon nodes deployed), while ensuring a degree of sensing coverage in a zone of interest and a required accuracy in locating events. We propose algorithms for solving these problems and demonstrate their effectiveness with results obtained from a high fidelity simulator.

  17. Six networks on a universal neuromorphic computing substrate

    Directory of Open Access Journals (Sweden)

    Thomas ePfeil

    2013-02-01

    Full Text Available In this study, we present a highly configurable neuromorphic computing substrate and use it for emulating several types of neural networks. At the heart of this system lies a mixed-signal chip, with analog implementations of neurons and synapses and digital transmission of action potentials. Major advantages of this emulation device, which has been explicitly designed as a universal neural network emulator, are its inherent parallelism and high acceleration factor compared to conventional computers. Its configurability allows the realization of almost arbitrary network topologies and the use of widely varied neuronal and synaptic parameters. Fixed-pattern noise inherent to analog circuitry is reduced by calibration routines. An integrated development environment allows neuroscientists to operate the device without any prior knowledge of neuromorphic circuit design. As a showcase for the capabilities of the system, we describe the successful emulation of six different neural networks which cover a broad spectrum of both structure and functionality.

  18. Self-organized criticality in a computer network model

    Science.gov (United States)

    Yuan; Ren; Shan

    2000-02-01

    We study the collective behavior of computer network nodes by using a cellular automaton model. The results show that when the load of network is constant, the throughputs and buffer contents of nodes are power-law distributed in both space and time. Also the feature of 1/f noise appears in the power spectrum of the change of the number of nodes that bear a fixed part of the system load. It can be seen as yet another example of self-organized criticality. Power-law decay in the distribution of buffer contents implies that heavy network congestion occurs with small probability. The temporal power-law distribution for throughput might be a reasonable explanation for the observed self-similarity in computer network traffic.

  19. Locally supervised neural networks for approximating terramechanics models

    Science.gov (United States)

    Song, Xingguo; Gao, Haibo; Ding, Liang; Spanos, Pol D.; Deng, Zongquan; Li, Zhijun

    2016-06-01

    Neural networks (NNs) have been widely implemented for identifying nonlinear models, and predicting the distribution of targets, due to their ability to store and learn training samples. However, for highly complex systems, it is difficult to build a robust global network model, and efficiently managing the large amounts of experimental data is often required in real-time applications. In this paper, an effective method for building local models is proposed to enhance robustness and learning speed in globally supervised NNs. Unlike NNs, Gaussian processes (GP) produce predictions that capture the uncertainty inherent in actual systems, and typically provides superior results. Therefore, in this study, each local NN is learned in the same manner as a Gaussian process. A mixture of local model NNs is created and then augmented using weighted regression. This proposed method, referred to as locally supervised NN for weighted regression like GP, is abbreviated as "LGPN", is utilized for approximating a wheel-terrain interaction model under fixed soil parameters. The prediction results show that the proposed method yields significant robustness, modeling accuracy, and rapid learning speed.

  20. Wirelessly powered sensor networks and computational RFID

    CERN Document Server

    2013-01-01

    The Wireless Identification and Sensing Platform (WISP) is the first of a new class of RF-powered sensing and computing systems.  Rather than being powered by batteries, these sensor systems are powered by radio waves that are either deliberately broadcast or ambient.  Enabled by ongoing exponential improvements in the energy efficiency of microelectronics, RF-powered sensing and computing is rapidly moving along a trajectory from impossible (in the recent past), to feasible (today), toward practical and commonplace (in the near future). This book is a collection of key papers on RF-powered sensing and computing systems including the WISP.  Several of the papers grew out of the WISP Challenge, a program in which Intel Corporation donated WISPs to academic applicants who proposed compelling WISP-based projects.  The book also includes papers presented at the first WISP Summit, a workshop held in Berkeley, CA in association with the ACM Sensys conference, as well as other relevant papers. The book provides ...

  1. Computing Path Tables for Quickest Multipaths In Computer Networks

    Energy Technology Data Exchange (ETDEWEB)

    Grimmell, W.C.

    2004-12-21

    We consider the transmission of a message from a source node to a terminal node in a network with n nodes and m links where the message is divided into parts and each part is transmitted over a different path in a set of paths from the source node to the terminal node. Here each link is characterized by a bandwidth and delay. The set of paths together with their transmission rates used for the message is referred to as a multipath. We present two algorithms that produce a minimum-end-to-end message delay multipath path table that, for every message length, specifies a multipath that will achieve the minimum end-to-end delay. The algorithms also generate a function that maps the minimum end-to-end message delay to the message length. The time complexities of the algorithms are O(n{sup 2}((n{sup 2}/logn) + m)min(D{sub max}, C{sub max})) and O(nm(C{sub max} + nmin(D{sub max}, C{sub max}))) when the link delays and bandwidths are non-negative integers. Here D{sub max} and C{sub max} are respectively the maximum link delay and maximum link bandwidth and C{sub max} and D{sub max} are greater than zero.

  2. Wireless wearable network and wireless body-centric network for future wearable computer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The wireless wearable network and wireless body-centric network can assistant to the user anywhere at anytime communicating with wireless components seamlessly. In this paper, the wireless wearable network and wireless body-centric network have been discussed, and the frequency band and human body effect has been estimated. The bluetooth and UWB technology can be used to construct the narrow band and the broad band wireless wearable network and wireless body-centric network separately. Further, the narrow band wireless wearable network and wireless body-centric network based on bluetooth technology has been constructed by integrated planar inverted-F antenna and the communication channel character has been studied by measurement. The results can provide the possibility of producing a prototype radio system that can be integrated with the wearable computers by suitable wireless technologies developed and applied to facilitate a reliable and continuous connectivity between the system units.

  3. Improved Object Localization Using Accurate Distance Estimation in Wireless Multimedia Sensor Networks.

    Directory of Open Access Journals (Sweden)

    Yasar Abbas Ur Rehman

    Full Text Available Object localization plays a key role in many popular applications of Wireless Multimedia Sensor Networks (WMSN and as a result, it has acquired a significant status for the research community. A significant body of research performs this task without considering node orientation, object geometry and environmental variations. As a result, the localized object does not reflect the real world scenarios. In this paper, a novel object localization scheme for WMSN has been proposed that utilizes range free localization, computer vision, and principle component analysis based algorithms. The proposed approach provides the best possible approximation of distance between a wmsn sink and an object, and the orientation of the object using image based information. Simulation results report 99% efficiency and an error ratio of 0.01 (around 1 ft when compared to other popular techniques.

  4. Improved Object Localization Using Accurate Distance Estimation in Wireless Multimedia Sensor Networks.

    Science.gov (United States)

    Ur Rehman, Yasar Abbas; Tariq, Muhammad; Khan, Omar Usman

    2015-01-01

    Object localization plays a key role in many popular applications of Wireless Multimedia Sensor Networks (WMSN) and as a result, it has acquired a significant status for the research community. A significant body of research performs this task without considering node orientation, object geometry and environmental variations. As a result, the localized object does not reflect the real world scenarios. In this paper, a novel object localization scheme for WMSN has been proposed that utilizes range free localization, computer vision, and principle component analysis based algorithms. The proposed approach provides the best possible approximation of distance between a wmsn sink and an object, and the orientation of the object using image based information. Simulation results report 99% efficiency and an error ratio of 0.01 (around 1 ft) when compared to other popular techniques.

  5. Syntactic computations in the language network: Characterising dynamic network properties using representational similarity analysis

    Directory of Open Access Journals (Sweden)

    Lorraine Komisarjevsky Tyler

    2013-05-01

    Full Text Available The core human capacity of syntactic analysis involves a left hemisphere network involving left inferior frontal gyrus (LIFG and posterior middle temporal gyrus (LMTG and the anatomical connections between them. Here we use MEG to determine the spatio-temporal properties of syntactic computations in this network. Listeners heard spoken sentences containing a local syntactic ambiguity (e.g. …landing planes…, at the offset of which they heard a disambiguating verb and decided whether it was an acceptable/unacceptable continuation of the sentence. We charted the time-course of processing and resolving syntactic ambiguity by measuring MEG responses from the onset of each word in the ambiguous phrase and the disambiguating word. We used representational similarity analysis (RSA to characterize syntactic information represented in the LIFG and LpMTG over time and to investigate their relationship to each other. Testing a variety of lexico-syntactic and ambiguity models against the MEG data, our results suggest early lexico-syntactic responses in the LpMTG and later effects of ambiguity in the LIFG, pointing to a clear differentiation in the functional roles of these two regions. Our results suggest the LpMTG represents and transmits lexical information to the LIFG, which responds to and resolves the ambiguity.

  6. The effect of faulty local detectors on a detection network.

    CERN Document Server

    Mirjalily, G

    2002-01-01

    Distributed detection theory has received increasing attention recently. Development of multiple sensors for signal detection results in improved performance and increased reliability. in a detection network, each local sensor decides locally whether a signal is detected or not. The local decisions are sent to the fusion center, where the final decision is made. In this paper, a theoretic approach is considered to data fusion when one of the sensors is faulty. If the fusion center does not have any knowledge of this fault, the performance of the system is different than its normal performance. The changes in the error probabilities depend on the type of the fault and on the threshold value of the fission center test. We derived some expressions of the changes in the values of error probabilities. For some type of faults, the system false alarm probability increases significantly, whereas for some other faults, the system detection probability decreases significantly. To illustrate the results, a numerical exa...

  7. Distributed Plume Source Localization Using Hierarchical Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    KUANG Xing-hong; LIU Yu-qing; WU Yan-xiang; SHAO Hui-he

    2009-01-01

    A hierarchical wireless sensor networks (WSN) was proposed to estimate the plume source location. Such WSN can be of tremendous help to emergency personnel trying to protect people from terrorist attacks or responding to an accident. The entire surveillant field is divided into several small sub-regions. In each sub-region, the localization algorithm based on the improved particle filter (IPF) was performed to estimate the location. Some improved methods such as weighted centroid, residual resampling were introduced to the IPF algorithm to increase the localization performance. This distributed estimation method elirninates many drawbacks inherent with the traditional centralized optimization method. Simulation results show that localization algorithm is efficient far estimating the plume source location.

  8. Efficient Capacity Computation and Power Optimization for Relay Networks

    CERN Document Server

    Parvaresh, Farzad

    2011-01-01

    The capacity or approximations to capacity of various single-source single-destination relay network models has been characterized in terms of the cut-set upper bound. In principle, a direct computation of this bound requires evaluating the cut capacity over exponentially many cuts. We show that the minimum cut capacity of a relay network under some special assumptions can be cast as a minimization of a submodular function, and as a result, can be computed efficiently. We use this result to show that the capacity, or an approximation to the capacity within a constant gap for the Gaussian, wireless erasure, and Avestimehr-Diggavi-Tse deterministic relay network models can be computed in polynomial time. We present some empirical results showing that computing constant-gap approximations to the capacity of Gaussian relay networks with around 300 nodes can be done in order of minutes. For Gaussian networks, cut-set capacities are also functions of the powers assigned to the nodes. We consider a family of power o...

  9. Computational analysis of light scattering from collagen fiber networks

    Science.gov (United States)

    Arifler, Dizem; Pavlova, Ina; Gillenwater, Ann; Richards-Kortum, Rebecca

    2007-07-01

    Neoplastic progression in epithelial tissues is accompanied by structural and morphological changes in the stromal collagen matrix. We used the Finite-Difference Time-Domain (FDTD) method, a popular computational technique for full-vector solution of complex problems in electromagnetics, to establish a relationship between structural properties of collagen fiber networks and light scattering, and to analyze how neoplastic changes alter stromal scattering properties. To create realistic collagen network models, we acquired optical sections from the stroma of fresh normal and neoplastic oral cavity biopsies using fluorescence confocal microscopy. These optical sections were then processed to construct three-dimensional collagen networks of different sizes as FDTD model input. Image analysis revealed that volume fraction of collagen fibers in the stroma decreases with neoplastic progression, and statistical texture features computed suggest that fibers tend to be more disconnected in neoplastic stroma. The FDTD modeling results showed that neoplastic fiber networks have smaller scattering cross-sections compared to normal networks of the same size, whereas high-angle scattering probabilities tend to be higher for neoplastic networks. Characterization of stromal scattering is expected to provide a basis to better interpret spectroscopic optical signals and to develop more reliable computational models to describe photon propagation in epithelial tissues.

  10. Localization System for a Mobile Robot Using Computer Vision Techniques

    Directory of Open Access Journals (Sweden)

    Rony Cruz Ramírez

    2012-05-01

    Full Text Available Mobile Robotics is a subject with multiple fields of action hence studies in this area are of vital importance. This paper describes the development of localization system for a mobile robot using Computer Vision. A webcam is placed at a height where the navigation environment can be seen. A LEGO NXT kit is used to build a wheeled mobile robot of differential drive configuration. The software is programmed in C++ using the functions library Open CV 2.0. this software then soft handles the webcam, does the processing of captured images, the calculation of the location, controls and communicates via Bluetooth. Also it implements a kinematic position control and performs several experiments to verify the reliability of the localization system. The results of one such experiment are described here.

  11. Energy Aware Computing in Cooperative Wireless Networks

    DEFF Research Database (Denmark)

    Olsen, Anders Brødløs; Fitzek, Frank H. P.; Koch, Peter

    2005-01-01

    In this work the idea of cooperation is applied to wireless communication systems. It is generally accepted that energy consumption is a significant design constraint for mobile handheld systems. We propose a novel method of cooperative task computing by distributing tasks among terminals over...... the unreliable wireless link. Principles of multi–processor energy aware task scheduling are used exploiting performance scalable technologies such as Dynamic Voltage Scaling (DVS). We introduce a novel mechanism referred to as D2VS and here it is shown by means of simulation that savings of 40% can be achieved....

  12. Internetworking issues: bridging Local Area Networks using systems of communicating machines.

    OpenAIRE

    Kadarma, Johny

    1989-01-01

    Approved for public release; distribution is unlimited The evolution in network and communication technology has led to the need to interconnect individual computer networks. Network designers are faced with the heterogeneity of networks just as they were previously faced with the heterogeneity of computers within a single network. In interconnecting various types of networks, therefore, many issues must be considered. This thesis identifies some of these issues as they pert...

  13. Fully Connected Neural Networks Ensemble with Signal Strength Clustering for Indoor Localization in Wireless Sensor Networks

    OpenAIRE

    2015-01-01

    The paper introduces a method which improves localization accuracy of the signal strength fingerprinting approach. According to the proposed method, entire localization area is divided into regions by clustering the fingerprint database. For each region a prototype of the received signal strength is determined and a dedicated artificial neural network (ANN) is trained by using only those fingerprints that belong to this region (cluster). Final estimation of the location is obtained by fusion ...

  14. 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).

  15. Implementation of Computer Assisted Test Selection System in Local Governments

    Directory of Open Access Journals (Sweden)

    Abdul Azis Basri

    2016-05-01

    Full Text Available As an evaluative way of selection of civil servant system in all government areas, Computer Assisted Test selection system was started to apply in 2013. In phase of implementation for first time in all areas in 2014, this system selection had trouble in several areas, such as registration procedure and passing grade. The main objective of this essay was to describe implementation of new selection system for civil servants in the local governments and to seek level of effectiveness of this selection system. This essay used combination of study literature and field survey which data collection was made by interviews, observations, and documentations from various sources, and to analyze the collected data, this essay used reduction, display data and verification for made the conclusion. The result of this essay showed, despite there a few parts that be problem of this system such as in the registration phase but almost all phases of implementation of CAT selection system in local government areas can be said was working clearly likes in preparation, implementation and result processing phase. And also this system was fulfilled two of three criterias of effectiveness for selection system, they were accuracy and trusty. Therefore, this selection system can be said as an effective way to select new civil servant. As suggestion, local governments have to make prime preparation in all phases of test and make a good feedback as evaluation mechanism and together with central government to seek, fix and improve infrastructures as supporting tool and competency of local residents.

  16. A Genetic Algorithm for the Bi-Level Topological Design of Local Area Networks.

    Directory of Open Access Journals (Sweden)

    José-Fernando Camacho-Vallejo

    Full Text Available Local access networks (LAN are commonly used as communication infrastructures which meet the demand of a set of users in the local environment. Usually these networks consist of several LAN segments connected by bridges. The topological LAN design bi-level problem consists on assigning users to clusters and the union of clusters by bridges in order to obtain a minimum response time network with minimum connection cost. Therefore, the decision of optimally assigning users to clusters will be made by the leader and the follower will make the decision of connecting all the clusters while forming a spanning tree. In this paper, we propose a genetic algorithm for solving the bi-level topological design of a Local Access Network. Our solution method considers the Stackelberg equilibrium to solve the bi-level problem. The Stackelberg-Genetic algorithm procedure deals with the fact that the follower's problem cannot be optimally solved in a straightforward manner. The computational results obtained from two different sets of instances show that the performance of the developed algorithm is efficient and that it is more suitable for solving the bi-level problem than a previous Nash-Genetic approach.

  17. Test experience on an ultrareliable computer communication network

    Science.gov (United States)

    Abbott, L. W.

    1984-01-01

    The dispersed sensor processing mesh (DSPM) is an experimental, ultra-reliable, fault-tolerant computer communications network that exhibits an organic-like ability to regenerate itself after suffering damage. The regeneration is accomplished by two routines - grow and repair. This paper discusses the DSPM concept for achieving fault tolerance and provides a brief description of the mechanization of both the experiment and the six-node experimental network. The main topic of this paper is the system performance of the growth algorithm contained in the grow routine. The characteristics imbued to DSPM by the growth algorithm are also discussed. Data from an experimental DSPM network and software simulation of larger DSPM-type networks are used to examine the inherent limitation on growth time by the growth algorithm and the relationship of growth time to network size and topology.

  18. Navigating traditional chinese medicine network pharmacology and computational tools.

    Science.gov (United States)

    Yang, Ming; Chen, Jia-Lei; Xu, Li-Wen; Ji, Guang

    2013-01-01

    The concept of "network target" has ushered in a new era in the field of traditional Chinese medicine (TCM). As a new research approach, network pharmacology is based on the analysis of network models and systems biology. Taking advantage of advancements in systems biology, a high degree of integration data analysis strategy and interpretable visualization provides deeper insights into the underlying mechanisms of TCM theories, including the principles of herb combination, biological foundations of herb or herbal formulae action, and molecular basis of TCM syndromes. In this study, we review several recent developments in TCM network pharmacology research and discuss their potential for bridging the gap between traditional and modern medicine. We briefly summarize the two main functional applications of TCM network models: understanding/uncovering and predicting/discovering. In particular, we focus on how TCM network pharmacology research is conducted and highlight different computational tools, such as network-based and machine learning algorithms, and sources that have been proposed and applied to the different steps involved in the research process. To make network pharmacology research commonplace, some basic network definitions and analysis methods are presented.

  19. Navigating Traditional Chinese Medicine Network Pharmacology and Computational Tools

    Directory of Open Access Journals (Sweden)

    Ming Yang

    2013-01-01

    Full Text Available The concept of “network target” has ushered in a new era in the field of traditional Chinese medicine (TCM. As a new research approach, network pharmacology is based on the analysis of network models and systems biology. Taking advantage of advancements in systems biology, a high degree of integration data analysis strategy and interpretable visualization provides deeper insights into the underlying mechanisms of TCM theories, including the principles of herb combination, biological foundations of herb or herbal formulae action, and molecular basis of TCM syndromes. In this study, we review several recent developments in TCM network pharmacology research and discuss their potential for bridging the gap between traditional and modern medicine. We briefly summarize the two main functional applications of TCM network models: understanding/uncovering and predicting/discovering. In particular, we focus on how TCM network pharmacology research is conducted and highlight different computational tools, such as network-based and machine learning algorithms, and sources that have been proposed and applied to the different steps involved in the research process. To make network pharmacology research commonplace, some basic network definitions and analysis methods are presented.

  20. Computational properties of networks of synchronous groups of spiking neurons.

    Science.gov (United States)

    Dayhoff, Judith E

    2007-09-01

    We demonstrate a model in which synchronously firing ensembles of neurons are networked to produce computational results. Each ensemble is a group of biological integrate-and-fire spiking neurons, with probabilistic interconnections between groups. An analogy is drawn in which each individual processing unit of an artificial neural network corresponds to a neuronal group in a biological model. The activation value of a unit in the artificial neural network corresponds to the fraction of active neurons, synchronously firing, in a biological neuronal group. Weights of the artificial neural network correspond to the product of the interconnection density between groups, the group size of the presynaptic group, and the postsynaptic potential heights in the synchronous group model. All three of these parameters can modulate connection strengths between neuronal groups in the synchronous group models. We give an example of nonlinear classification (XOR) and a function approximation example in which the capability of the artificial neural network can be captured by a neural network model with biological integrate-and-fire neurons configured as a network of synchronously firing ensembles of such neurons. We point out that the general function approximation capability proven for feedforward artificial neural networks appears to be approximated by networks of neuronal groups that fire in synchrony, where the groups comprise integrate-and-fire neurons. We discuss the advantages of this type of model for biological systems, its possible learning mechanisms, and the associated timing relationships.

  1. Predicting Traffic Flow in Local Area Networks by the Largest Lyapunov Exponent

    Directory of Open Access Journals (Sweden)

    Yan Liu

    2016-01-01

    Full Text Available The dynamics of network traffic are complex and nonlinear, and chaotic behaviors and their prediction, which play an important role in local area networks (LANs, are studied in detail, using the largest Lyapunov exponent. With the introduction of phase space reconstruction based on the time sequence, the high-dimensional traffic is projected onto the low dimension reconstructed phase space, and a reduced dynamic system is obtained from the dynamic system viewpoint. Then, a numerical method for computing the largest Lyapunov exponent of the low-dimensional dynamic system is presented. Further, the longest predictable time, which is related to chaotic behaviors in the system, is studied using the largest Lyapunov exponent, and the Wolf method is used to predict the evolution of the traffic in a local area network by both Dot and Interval predictions, and a reliable result is obtained by the presented method. As the conclusion, the results show that the largest Lyapunov exponent can be used to describe the sensitivity of the trajectory in the reconstructed phase space to the initial values. Moreover, Dot Prediction can effectively predict the flow burst. The numerical simulation also shows that the presented method is feasible and efficient for predicting the complex dynamic behaviors in LAN traffic, especially for congestion and attack in networks, which are the main two complex phenomena behaving as chaos in networks.

  2. Wireless local area network in a prehospital environment

    Directory of Open Access Journals (Sweden)

    Grimes Gary J

    2004-08-01

    Full Text Available Abstract Background Wireless local area networks (WLANs are considered the next generation of clinical data network. They open the possibility for capturing clinical data in a prehospital setting (e.g., a patient's home using various devices, such as personal digital assistants, laptops, digital electrocardiogram (EKG machines, and even cellular phones, and transmitting the captured data to a physician or hospital. The transmission rate is crucial to the applicability of the technology in the prehospital setting. Methods We created two separate WLANs to simulate a virtual local are network environment such as in a patient's home or an emergency room (ER. The effects of different methods of data transmission, number of clients, and roaming among different access points on the file transfer rate were determined. Results The present results suggest that it is feasible to transfer small files such as patient demographics and EKG data from the patient's home to the ER at a reasonable speed. Encryption, user control, and access control were implemented and results discussed. Conclusions Implementing a WLAN in a centrally managed and multiple-layer-controlled access control server is the key to ensuring its security and accessibility. Future studies should focus on product capacity, speed, compatibility, interoperability, and security management.

  3. Propagation of computer virus both across the Internet and external computers: A complex-network approach

    Science.gov (United States)

    Gan, Chenquan; Yang, Xiaofan; Liu, Wanping; Zhu, Qingyi; Jin, Jian; He, Li

    2014-08-01

    Based on the assumption that external computers (particularly, infected external computers) are connected to the Internet, and by considering the influence of the Internet topology on computer virus spreading, this paper establishes a novel computer virus propagation model with a complex-network approach. This model possesses a unique (viral) equilibrium which is globally attractive. Some numerical simulations are also given to illustrate this result. Further study shows that the computers with higher node degrees are more susceptible to infection than those with lower node degrees. In this regard, some appropriate protective measures are suggested.

  4. High Energy Physics Experiments In Grid Computing Networks

    Directory of Open Access Journals (Sweden)

    Andrzej Olszewski

    2008-01-01

    Full Text Available The demand for computing resources used for detector simulations and data analysis in HighEnergy Physics (HEP experiments is constantly increasing due to the development of studiesof rare physics processes in particle interactions. The latest generation of experiments at thenewly built LHC accelerator at CERN in Geneva is planning to use computing networks fortheir data processing needs. A Worldwide LHC Computing Grid (WLCG organization hasbeen created to develop a Grid with properties matching the needs of these experiments. Inthis paper we present the use of Grid computing by HEP experiments and describe activitiesat the participating computing centers with the case of Academic Computing Center, ACKCyfronet AGH, Kraków, Poland.

  5. Intracellular spatial localization regulated by the microtubule network.

    Directory of Open Access Journals (Sweden)

    Jing Chen

    Full Text Available The commonly recognized mechanisms for spatial regulation inside the cell are membrane-bounded compartmentalization and biochemical association with subcellular organelles. We use computational modeling to investigate another spatial regulation mechanism mediated by the microtubule network in the cell. Our results demonstrate that the mitotic spindle can impose strong sequestration and concentration effects on molecules with binding affinity for microtubules, especially dynein-directed cargoes. The model can recapitulate the essence of three experimental observations on distinct microtubule network morphologies: the sequestration of germ plasm components by the mitotic spindles in the Drosophila syncytial embryo, the asymmetric cell division initiated by the time delay in centrosome maturation in the Drosophila neuroblast, and the diffusional block between neighboring energids in the Drosophila syncytial embryo. Our model thus suggests that the cell cycle-dependent changes in the microtubule network are critical for achieving different spatial regulation effects. The microtubule network provides a spatially extensive docking platform for molecules and gives rise to a "structured cytoplasm", in contrast to a free and fluid environment.

  6. Small-world networks in neuronal populations: a computational perspective.

    Science.gov (United States)

    Zippo, Antonio G; Gelsomino, Giuliana; Van Duin, Pieter; Nencini, Sara; Caramenti, Gian Carlo; Valente, Maurizio; Biella, Gabriele E M

    2013-08-01

    The analysis of the brain in terms of integrated neural networks may offer insights on the reciprocal relation between structure and information processing. Even with inherent technical limits, many studies acknowledge neuron spatial arrangements and communication modes as key factors. In this perspective, we investigated the functional organization of neuronal networks by explicitly assuming a specific functional topology, the small-world network. We developed two different computational approaches. Firstly, we asked whether neuronal populations actually express small-world properties during a definite task, such as a learning task. For this purpose we developed the Inductive Conceptual Network (ICN), which is a hierarchical bio-inspired spiking network, capable of learning invariant patterns by using variable-order Markov models implemented in its nodes. As a result, we actually observed small-world topologies during learning in the ICN. Speculating that the expression of small-world networks is not solely related to learning tasks, we then built a de facto network assuming that the information processing in the brain may occur through functional small-world topologies. In this de facto network, synchronous spikes reflected functional small-world network dependencies. In order to verify the consistency of the assumption, we tested the null-hypothesis by replacing the small-world networks with random networks. As a result, only small world networks exhibited functional biomimetic characteristics such as timing and rate codes, conventional coding strategies and neuronal avalanches, which are cascades of bursting activities with a power-law distribution. Our results suggest that small-world functional configurations are liable to underpin brain information processing at neuronal level.

  7. Parameter Selection and Performance Comparison of Particle Swarm Optimization in Sensor Networks Localization.

    Science.gov (United States)

    Cui, Huanqing; Shu, Minglei; Song, Min; Wang, Yinglong

    2017-03-01

    Localization is a key technology in wireless sensor networks. Faced with the challenges of the sensors' memory, computational constraints, and limited energy, particle swarm optimization has been widely applied in the localization of wireless sensor networks, demonstrating better performance than other optimization methods. In particle swarm optimization-based localization algorithms, the variants and parameters should be chosen elaborately to achieve the best performance. However, there is a lack of guidance on how to choose these variants and parameters. Further, there is no comprehensive performance comparison among particle swarm optimization algorithms. The main contribution of this paper is three-fold. First, it surveys the popular particle swarm optimization variants and particle swarm optimization-based localization algorithms for wireless sensor networks. Secondly, it presents parameter selection of nine particle swarm optimization variants and six types of swarm topologies by extensive simulations. Thirdly, it comprehensively compares the performance of these algorithms. The results show that the particle swarm optimization with constriction coefficient using ring topology outperforms other variants and swarm topologies, and it performs better than the second-order cone programming algorithm.

  8. Parameter Selection and Performance Comparison of Particle Swarm Optimization in Sensor Networks Localization

    Directory of Open Access Journals (Sweden)

    Huanqing Cui

    2017-03-01

    Full Text Available Localization is a key technology in wireless sensor networks. Faced with the challenges of the sensors’ memory, computational constraints, and limited energy, particle swarm optimization has been widely applied in the localization of wireless sensor networks, demonstrating better performance than other optimization methods. In particle swarm optimization-based localization algorithms, the variants and parameters should be chosen elaborately to achieve the best performance. However, there is a lack of guidance on how to choose these variants and parameters. Further, there is no comprehensive performance comparison among particle swarm optimization algorithms. The main contribution of this paper is three-fold. First, it surveys the popular particle swarm optimization variants and particle swarm optimization-based localization algorithms for wireless sensor networks. Secondly, it presents parameter selection of nine particle swarm optimization variants and six types of swarm topologies by extensive simulations. Thirdly, it comprehensively compares the performance of these algorithms. The results show that the particle swarm optimization with constriction coefficient using ring topology outperforms other variants and swarm topologies, and it performs better than the second-order cone programming algorithm.

  9. Parameter Selection and Performance Comparison of Particle Swarm Optimization in Sensor Networks Localization

    Science.gov (United States)

    Cui, Huanqing; Shu, Minglei; Song, Min; Wang, Yinglong

    2017-01-01

    Localization is a key technology in wireless sensor networks. Faced with the challenges of the sensors’ memory, computational constraints, and limited energy, particle swarm optimization has been widely applied in the localization of wireless sensor networks, demonstrating better performance than other optimization methods. In particle swarm optimization-based localization algorithms, the variants and parameters should be chosen elaborately to achieve the best performance. However, there is a lack of guidance on how to choose these variants and parameters. Further, there is no comprehensive performance comparison among particle swarm optimization algorithms. The main contribution of this paper is three-fold. First, it surveys the popular particle swarm optimization variants and particle swarm optimization-based localization algorithms for wireless sensor networks. Secondly, it presents parameter selection of nine particle swarm optimization variants and six types of swarm topologies by extensive simulations. Thirdly, it comprehensively compares the performance of these algorithms. The results show that the particle swarm optimization with constriction coefficient using ring topology outperforms other variants and swarm topologies, and it performs better than the second-order cone programming algorithm. PMID:28257060

  10. Local communities obstruct global consensus: Naming game on multi-local-world networks

    CERN Document Server

    Lou, Yang; Fan, Zhengping; Xiang, Luna

    2016-01-01

    Community structure is essential for social communications, where individuals belonging to the same community are much more actively interacting and communicating with each other than those in different communities within the human society. Naming game, on the other hand, is a social communication model that simulates the process of learning a name of an object within a community of humans, where the individuals can reach global consensus on naming an object asymptotically through iterative pair-wise conversations. The underlying communication network indicates the relationships among the individuals. In this paper, three typical topologies of human communication networks, namely random-graph, small-world and scale-free networks, are employed, which are embedded with the multi-local-world community structure, to study the naming game. Simulations show that 1) when the intra-community connections increase while the inter-community connections remain to be unchanged, the convergence to global consensus is slow ...

  11. Identifying failure in a tree network of a parallel computer

    Science.gov (United States)

    Archer, Charles J.; Pinnow, Kurt W.; Wallenfelt, Brian P.

    2010-08-24

    Methods, parallel computers, and products are provided for identifying failure in a tree network of a parallel computer. The parallel computer includes one or more processing sets including an I/O node and a plurality of compute nodes. For each processing set embodiments include selecting a set of test compute nodes, the test compute nodes being a subset of the compute nodes of the processing set; measuring the performance of the I/O node of the processing set; measuring the performance of the selected set of test compute nodes; calculating a current test value in dependence upon the measured performance of the I/O node of the processing set, the measured performance of the set of test compute nodes, and a predetermined value for I/O node performance; and comparing the current test value with a predetermined tree performance threshold. If the current test value is below the predetermined tree performance threshold, embodiments include selecting another set of test compute nodes. If the current test value is not below the predetermined tree performance threshold, embodiments include selecting from the test compute nodes one or more potential problem nodes and testing individually potential problem nodes and links to potential problem nodes.

  12. Localized Recursive Estimation in Energy Constrained Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Bang Wang

    2006-06-01

    Full Text Available This paper proposes a localized recursive estimation scheme for parameter estimation in wireless sensor networks. Given any parameter of a target occurring at some location and time, a number of sensors recursively estimate the parameter by using their local measurements of the parameter that is attenuated with the distance between a sensor and the target location and corrupted by noise. Compared with centralized estimation schemes that transmit all encoded measurements to a sink (or a fusion center, the recursive scheme needs only to transmit the final estimate to a sink. When the sink is faraway from the sensors and multihop communications have to be used, using localized recursive estimation can help to reduce energy consumption and reduce network traffic load. A sensor sequence with the fastest convergence rate is identified, by which the variance of estimation error reduces faster than all other sequences. In the case of adjustable transmission power, a heuristic has been proposed to find a sensor sequence with the minimum total transmission power when performing the recursive estimation. Numerical examples have been used to compare the performance of the proposed scheme with that of a centralized estimation scheme and have also shown the effectiveness of the proposed heuristic.

  13. Local Positioning Services on IEEE 802.11 Networks

    Directory of Open Access Journals (Sweden)

    A. M. Vegni

    2008-06-01

    Full Text Available This paper deals with localization services in IEEE 802.11 networks, for indoor environment. The proposed solution processes the Time Of Arrival of location packets sent by a Mobile Terminal, that makes access in a IEEE 802.11 network. A set of Location Supporting Nodes and a Location Support Server composes an indoor location services architecture. A fully compatible IEEE 802.11 Localization Services protocol supporting data exchange related to both TOA measurement and processing is reported. Simulation results show the method efficiency in both IEEE 802.11 PCF and DCF modes. Assessment of the maximum number of users for which location services can be provided is also reported. Since high localization accuracy requires large bandwidth, a broadband antenna for LSN and LSS was designed. The related results are reported in the second part of the paper. The antenna works at 5.0 GHz (centre frequency in broadband mode and is matched on the wireless operating frequencies with a percentage more than 8% (1:1.5 VSWR.

  14. Exploring the Future of Out-of-Core Computing with Compute-Local Non-Volatile Memory

    Directory of Open Access Journals (Sweden)

    Myoungsoo Jung

    2014-01-01

    Full Text Available Drawing parallels to the rise of general purpose graphical processing units (GPGPUs as accelerators for specific high-performance computing (HPC workloads, there is a rise in the use of non-volatile memory (NVM as accelerators for I/O-intensive scientific applications. However, existing works have explored use of NVM within dedicated I/O nodes, which are distant from the compute nodes that actually need such acceleration. As NVM bandwidth begins to out-pace point-to-point network capacity, we argue for the need to break from the archetype of completely separated storage. Therefore, in this work we investigate co-location of NVM and compute by varying I/O interfaces, file systems, types of NVM, and both current and future SSD architectures, uncovering numerous bottlenecks implicit in these various levels in the I/O stack. We present novel hardware and software solutions, including the new Unified File System (UFS, to enable fuller utilization of the new compute-local NVM storage. Our experimental evaluation, which employs a real-world Out-of-Core (OoC HPC application, demonstrates throughput increases in excess of an order of magnitude over current approaches.

  15. Local Events and Dynamics on Weighted Complex Networks

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hui; GAO Zi-You

    2006-01-01

    @@ We examine the weighted networks grown and evolved by local events, such as the addition of new vertices and links and we show that depending on frequency of the events, a generalized power-law distribution of strength can emerge. Continuum theory is used to predict the scaling function as well as the exponents, which is in good agreement with the numerical simulation results. Depending on event frequency, power-law distributions of degree and weight can also be expected. Probability saturation phenomena for small strength and degree in many real world networks can be reproduced. Particularly, the non-trivial clustering coefficient, assortativity coefficient and degree-strength correlation in our model are all consistent with empirical evidences.

  16. Quality of local control for simple sewer networks

    Science.gov (United States)

    Kolechkina, Alla; van Nooijen, Ronald

    2016-04-01

    Combined sewer networks, where both foul water and storm water are transported through the same system, tend to develop into complex networks due to expansion of towns and villages. The transport capacity of these systems is always limited, so occasional controlled spills into surface water, combined sewer overflows (CSO), are part of the normal operating procedure. Occasionally the ideas and rules present in the original design are not respected when the system is extended to cover a larger area. One way to deal with this problem is to implement central control. Another is to add pipes and hardware to bring the extended system into line with the original rules and ideas. We show that for a design rule often followed in the Netherlands, local control does quite well as long as the rule is respected and there are no large variations in precipitation intensity over the area covered by the system.

  17. A computational study of routing algorithms for realistic transportation networks

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, R.; Marathe, M.V.; Nagel, K.

    1998-12-01

    The authors carry out an experimental analysis of a number of shortest path (routing) algorithms investigated in the context of the TRANSIMS (Transportation Analysis and Simulation System) project. The main focus of the paper is to study how various heuristic and exact solutions, associated data structures affected the computational performance of the software developed especially for realistic transportation networks. For this purpose the authors have used Dallas Fort-Worth road network with very high degree of resolution. The following general results are obtained: (1) they discuss and experimentally analyze various one-one shortest path algorithms, which include classical exact algorithms studied in the literature as well as heuristic solutions that are designed to take into account the geometric structure of the input instances; (2) they describe a number of extensions to the basic shortest path algorithm. These extensions were primarily motivated by practical problems arising in TRANSIMS and ITS (Intelligent Transportation Systems) related technologies. Extensions discussed include--(i) time dependent networks, (ii) multi-modal networks, (iii) networks with public transportation and associated schedules. Computational results are provided to empirically compare the efficiency of various algorithms. The studies indicate that a modified Dijkstra`s algorithm is computationally fast and an excellent candidate for use in various transportation planning applications as well as ITS related technologies.

  18. Computation of gradually varied flow in compound open channel networks

    Indian Academy of Sciences (India)

    H Prashanth Reddy; M Hanif Chaudhry; Jasim Imran

    2014-12-01

    Although, natural channels are rarely rectangular or trapezoidal in cross section, these cross sections are assumed for the computation of steady, gradually varied flow in open channel networks. The accuracy of the computed results, therefore, becomes questionable due to differences in the hydraulic and geometric characteristics of the main channel and floodplains. To overcome these limitations, an algorithm is presented in this paper to compute steady, gradually varied flow in an open-channel network with compound cross sections. As compared to the presently available methods, the methodology is more general and suitable for application to compound and trapezoidal channel cross sections in series channels, tree-type or looped networks. In this method, the energy and continuity equations are solved for steady, gradually varied flow by the Newton–Raphson method and the proposed methodology is applied to tree-type and looped-channel networks. An algorithm is presented to determine multiple critical depths in a compound channel. Modifications in channel geometry are presented to avoid the occurrence of multiple critical depths. The occurrence of only one critical depth in a compound cross section with modified geometry is demonstrated for a tree-type channel network.

  19. Hybrid computing using a neural network with dynamic external memory.

    Science.gov (United States)

    Graves, Alex; Wayne, Greg; Reynolds, Malcolm; Harley, Tim; Danihelka, Ivo; Grabska-Barwińska, Agnieszka; Colmenarejo, Sergio Gómez; Grefenstette, Edward; Ramalho, Tiago; Agapiou, John; Badia, Adrià Puigdomènech; Hermann, Karl Moritz; Zwols, Yori; Ostrovski, Georg; Cain, Adam; King, Helen; Summerfield, Christopher; Blunsom, Phil; Kavukcuoglu, Koray; Hassabis, Demis

    2016-10-27

    Artificial neural networks are remarkably adept at sensory processing, sequence learning and reinforcement learning, but are limited in their ability to represent variables and data structures and to store data over long timescales, owing to the lack of an external memory. Here we introduce a machine learning model called a differentiable neural computer (DNC), which consists of a neural network that can read from and write to an external memory matrix, analogous to the random-access memory in a conventional computer. Like a conventional computer, it can use its memory to represent and manipulate complex data structures, but, like a neural network, it can learn to do so from data. When trained with supervised learning, we demonstrate that a DNC can successfully answer synthetic questions designed to emulate reasoning and inference problems in natural language. We show that it can learn tasks such as finding the shortest path between specified points and inferring the missing links in randomly generated graphs, and then generalize these tasks to specific graphs such as transport networks and family trees. When trained with reinforcement learning, a DNC can complete a moving blocks puzzle in which changing goals are specified by sequences of symbols. Taken together, our results demonstrate that DNCs have the capacity to solve complex, structured tasks that are inaccessible to neural networks without external read-write memory.

  20. Recurrent Neural Network for Computing the Drazin Inverse.

    Science.gov (United States)

    Stanimirović, Predrag S; Zivković, Ivan S; Wei, Yimin

    2015-11-01

    This paper presents a recurrent neural network (RNN) for computing the Drazin inverse of a real matrix in real time. This recurrent neural network (RNN) is composed of n independent parts (subnetworks), where n is the order of the input matrix. These subnetworks can operate concurrently, so parallel and distributed processing can be achieved. In this way, the computational advantages over the existing sequential algorithms can be attained in real-time applications. The RNN defined in this paper is convenient for an implementation in an electronic circuit. The number of neurons in the neural network is the same as the number of elements in the output matrix, which represents the Drazin inverse. The difference between the proposed RNN and the existing ones for the Drazin inverse computation lies in their network architecture and dynamics. The conditions that ensure the stability of the defined RNN as well as its convergence toward the Drazin inverse are considered. In addition, illustrative examples and examples of application to the practical engineering problems are discussed to show the efficacy of the proposed neural network.

  1. Bayesian network approach for modeling local failure in lung cancer

    Science.gov (United States)

    Oh, Jung Hun; Craft, Jeffrey; Al-Lozi, Rawan; Vaidya, Manushka; Meng, Yifan; Deasy, Joseph O; Bradley, Jeffrey D; Naqa, Issam El

    2011-01-01

    Locally advanced non-small cell lung cancer (NSCLC) patients suffer from a high local failure rate following radiotherapy. Despite many efforts to develop new dose-volume models for early detection of tumor local failure, there was no reported significant improvement in their application prospectively. Based on recent studies of biomarker proteins’ role in hypoxia and inflammation in predicting tumor response to radiotherapy, we hypothesize that combining physical and biological factors with a suitable framework could improve the overall prediction. To test this hypothesis, we propose a graphical Bayesian network framework for predicting local failure in lung cancer. The proposed approach was tested using two different datasets of locally advanced NSCLC patients treated with radiotherapy. The first dataset was collected retrospectively, which is comprised of clinical and dosimetric variables only. The second dataset was collected prospectively in which in addition to clinical and dosimetric information, blood was drawn from the patients at various time points to extract candidate biomarkers as well. Our preliminary results show that the proposed method can be used as an efficient method to develop predictive models of local failure in these patients and to interpret relationships among the different variables in the models. We also demonstrate the potential use of heterogenous physical and biological variables to improve the model prediction. With the first dataset, we achieved better performance compared with competing Bayesian-based classifiers. With the second dataset, the combined model had a slightly higher performance compared to individual physical and biological models, with the biological variables making the largest contribution. Our preliminary results highlight the potential of the proposed integrated approach for predicting post-radiotherapy local failure in NSCLC patients. PMID:21335651

  2. Computational neural networks driving complex analytical problem solving.

    Science.gov (United States)

    Hanrahan, Grady

    2010-06-01

    Neural network computing demonstrates advanced analytical problem solving abilities to meet the demands of modern chemical research. (To listen to a podcast about this article, please go to the Analytical Chemistry multimedia page at pubs.acs.org/page/ancham/audio/index.html .).

  3. Efficient Computation of Distance Sketches in Distributed Networks

    CERN Document Server

    Sarma, Atish Das; Pandurangan, Gopal

    2011-01-01

    Distance computation is one of the most fundamental primitives used in communication networks. The cost of effectively and accurately computing pairwise network distances can become prohibitive in large-scale networks such as the Internet and Peer-to-Peer (P2P) networks. To negotiate the rising need for very efficient distance computation, approximation techniques for numerous variants of this question have recently received significant attention in the literature. The goal is to preprocess the graph and store a small amount of information such that whenever a query for any pairwise distance is issued, the distance can be well approximated (i.e., with small stretch) very quickly in an online fashion. Specifically, the pre-processing (usually) involves storing a small sketch with each node, such that at query time only the sketches of the concerned nodes need to be looked up to compute the approximate distance. In this paper, we present the first theoretical study of distance sketches derived from distance ora...

  4. Fish species recognition using computer vision and a neural network

    NARCIS (Netherlands)

    Storbeck, F.; Daan, B.

    2001-01-01

    A system is described to recognize fish species by computer vision and a neural network program. The vision system measures a number of features of fish as seen by a camera perpendicular to a conveyor belt. The features used here are the widths and heights at various locations along the fish. First

  5. The Poor Man's Guide to Computer Networks and their Applications

    DEFF Research Database (Denmark)

    Sharp, Robin

    2003-01-01

    These notes for DTU course 02220, Concurrent Programming, give an introduction to computer networks, with focus on the modern Internet. Basic Internet protocols such as IP, TCP and UDP are presented, and two Internet application protocols, SMTP and HTTP, are described in some detail. Techniques...

  6. Improving a Computer Networks Course Using the Partov Simulation Engine

    Science.gov (United States)

    Momeni, B.; Kharrazi, M.

    2012-01-01

    Computer networks courses are hard to teach as there are many details in the protocols and techniques involved that are difficult to grasp. Employing programming assignments as part of the course helps students to obtain a better understanding and gain further insight into the theoretical lectures. In this paper, the Partov simulation engine and…

  7. Improving a Computer Networks Course Using the Partov Simulation Engine

    Science.gov (United States)

    Momeni, B.; Kharrazi, M.

    2012-01-01

    Computer networks courses are hard to teach as there are many details in the protocols and techniques involved that are difficult to grasp. Employing programming assignments as part of the course helps students to obtain a better understanding and gain further insight into the theoretical lectures. In this paper, the Partov simulation engine and…

  8. Computing Nash Equilibrium in Wireless Ad Hoc Networks

    DEFF Research Database (Denmark)

    Bulychev, Peter E.; David, Alexandre; Larsen, Kim G.

    2012-01-01

    This paper studies the problem of computing Nash equilibrium in wireless networks modeled by Weighted Timed Automata. Such formalism comes together with a logic that can be used to describe complex features such as timed energy constraints. Our contribution is a method for solving this problem us...

  9. An Analysis of Attitudes toward Computer Networks and Internet Addiction.

    Science.gov (United States)

    Tsai, Chin-Chung; Lin, Sunny S. J.

    The purpose of this study was to explore the interplay between young people's attitudes toward computer networks and Internet addiction. After analyzing questionnaire responses of an initial sample of 615 Taiwanese high school students, 78 subjects, viewed as possible Internet addicts, were selected for further explorations. It was found that…

  10. Computer-Supported Modelling of Multi modal Transportation Networks Rationalization

    Directory of Open Access Journals (Sweden)

    Ratko Zelenika

    2007-09-01

    Full Text Available This paper deals with issues of shaping and functioning ofcomputer programs in the modelling and solving of multimoda Itransportation network problems. A methodology of an integrateduse of a programming language for mathematical modellingis defined, as well as spreadsheets for the solving of complexmultimodal transportation network problems. The papercontains a comparison of the partial and integral methods ofsolving multimodal transportation networks. The basic hypothesisset forth in this paper is that the integral method results inbetter multimodal transportation network rationalization effects,whereas a multimodal transportation network modelbased on the integral method, once built, can be used as the basisfor all kinds of transportation problems within multimodaltransport. As opposed to linear transport problems, multimodaltransport network can assume very complex shapes. This papercontains a comparison of the partial and integral approach totransp01tation network solving. In the partial approach, astraightforward model of a transp01tation network, which canbe solved through the use of the Solver computer tool within theExcel spreadsheet inteiface, is quite sufficient. In the solving ofa multimodal transportation problem through the integralmethod, it is necessmy to apply sophisticated mathematicalmodelling programming languages which supp01t the use ofcomplex matrix functions and the processing of a vast amountof variables and limitations. The LINGO programming languageis more abstract than the Excel spreadsheet, and it requiresa certain programming knowledge. The definition andpresentation of a problem logic within Excel, in a manner whichis acceptable to computer software, is an ideal basis for modellingin the LINGO programming language, as well as a fasterand more effective implementation of the mathematical model.This paper provides proof for the fact that it is more rational tosolve the problem of multimodal transportation networks by

  11. Wireless Local Area Network Adaptive Modulation and Coding Technology Research

    Institute of Scientific and Technical Information of China (English)

    SUN Zeng-you; SUN Xiao-fan

    2012-01-01

      Expound the existing modulation mode of the present wireless local area network. Directing at the problem that when single modulation method conveys data with high speed in the frequency selective fading channel, the system throughput will be declined and the efficiency of the spectrum will be lowered . Put forward the scheme that the OFDM sub-carrier will use differ⁃ent modulation modes after dynamic groups by amplitude frequency response. Simulation results show that the scheme will lower the complexity of the system achievement, and can get a higher spectrum efficiency.

  12. Computational neuropsychiatry – schizophrenia as a cognitive brain network disorder

    Directory of Open Access Journals (Sweden)

    Maria R Dauvermann

    2014-03-01

    Full Text Available Computational modelling of functional brain networks has advanced the understanding of higher cognitive function. It is hypothesised that functional networks mediating higher cognitive processes are disrupted in people with schizophrenia. In this article, we review studies that applied measures of functional and effective connectivity to fMRI data during cognitive tasks, in particular working memory fMRI studies. We provide a conceptual summary of the main findings in fMRI data and their relationship with neurotransmitter systems, which are known to be altered in individuals with schizophrenia. We consider possible developments in computational neuropsychiatry, which are likely to further our understanding of how functional networks are altered in schizophrenia.

  13. Computer network time synchronization the network time protocol on earth and in space

    CERN Document Server

    Mills, David L

    2010-01-01

    Carefully coordinated, reliable, and accurate time synchronization is vital to a wide spectrum of fields-from air and ground traffic control, to buying and selling goods and services, to TV network programming. Ill-gotten time could even lead to the unimaginable and cause DNS caches to expire, leaving the entire Internet to implode on the root servers.Written by the original developer of the Network Time Protocol (NTP), Computer Network Time Synchronization: The Network Time Protocol on Earth and in Space, Second Edition addresses the technological infrastructure of time dissemination, distrib

  14. Power Grid Network Evolutions for Local Energy Trading

    CERN Document Server

    Pagani, Giuliano Andrea

    2012-01-01

    The shift towards a energy Grid dominated by prosumers (consumers and producers of energy) will inevitably have repercussions on the distribution infrastructure. Today it is a hierarchical one designed to deliver energy from large scale facilities to end-users. Tomorrow it will be a capillary infrastructure at the medium and Low Voltage levels that will support local energy trading among prosumers. In our previous work, we analyzed the Dutch Power Grid and made an initial analysis of the economic impact topological properties have on decentralized energy trading. In this paper, we go one step further and investigate how different networks topologies and growth models facilitate the emergence of a decentralized market. In particular, we show how the connectivity plays an important role in improving the properties of reliability and path-cost reduction. From the economic point of view, we estimate how the topological evolutions facilitate local electricity distribution, taking into account the main cost ingredi...

  15. Local election blogs: Networking among the political elite

    DEFF Research Database (Denmark)

    Bock Segaard, Signe; Agger Nielsen, Jeppe

    2013-01-01

    : participants and interaction. Next, we apply our framework in a case study of election blogs in twelve Norwegian municipalities using multiple data sources. In contrast to the democratic vision of social media, our analysis demonstrates that election blogs are primarily used by those who are politically active......This article explores the role of social media (essentially blogs) in the 2011 Norwegian local election campaigns. We commence by developing a framework for investigating political communication using the social media that conceptualises the horizontal and vertical conversation along two dimensions...... in the local election campaign. While candidates say they want to connect with the electorate, in practice they are networking with each other. Our findings are discussed in light of the institutional setting in which the blogging take place, and the specific social media under investigation....

  16. Distributed localization using mobile beacons in wireless sensor networks

    Institute of Scientific and Technical Information of China (English)

    KUANG Xing-hong; SHAO Hui-he

    2007-01-01

    A new distributed node localization algorithm named mobile beacons-improved particle filter (MB-IPF) was proposed. In the algorithm, the mobile nodes equipped with globe position system (GPS) move around in the wireless sensor network (WSN) field based on the Gauss-Markov mobility model, and periodically broadcast the beacon messages. Each unknown node estimates its location in a fully distributed mode based on the received mobile beacons. The localization algorithm is based on the IPF and several refinements, including the proposed weighted centroid algorithm, the residual resampling algorithm, and the markov chain monte carlo (MCMC) method etc., which were also introduced for performance improvement. The simulation results show that our proposed algorithm is efficient for most applications.

  17. Connected or informed?: Local Twitter networking in a London neighbourhood

    Directory of Open Access Journals (Sweden)

    John Bingham-Hall

    2015-08-01

    Full Text Available This paper asks whether geographically localised, or ‘hyperlocal’, uses of Twitter succeed in creating peer-to-peer neighbourhood networks or simply act as broadcast media at a reduced scale. Literature drawn from the smart cities discourse and from a UK research project into hyperlocal media, respectively, take on these two opposing interpretations. Evidence gathered in the case study presented here is consistent with the latter, and on this basis we criticise the notion that hyperlocal social media can be seen as a community in itself. We demonstrate this by creating a network map of Twitter followers of a popular hyperlocal blog in Brockley, southeast London. We describe various attributes of this network including its average degree and clustering coefficient to suggest that a small and highly connected cluster of visible local entities such as businesses form a clique at the centre of this network, with individual residents following these but not one another. We then plot the locations of these entities and demonstrate that sub-communities in the network are formed due to close geographical proximity between smaller sets of businesses. These observations are illustrated with qualitative evidence from interviews with users who suggest instead that rather than being connected to one another they benefit from what has been described as ‘neighbourhood storytelling’. Despite the limitations of working with Twitter data, we propose that this multi-modal approach offers a valuable way to investigate the experience of using social media as a communication tool in urban neighbourhoods.

  18. LAN Ho! A Guide to Networking Personal Computers.

    Science.gov (United States)

    Daly, Kevin F.

    1993-01-01

    Provides examples of common administrative tasks in school district offices that can be expedited using an administrative local area network (LAN). Explains how districts should develop a master plan installing a LAN. Figures display the LAN components, planning sheets, and an electrical requirement calculator chart. Discusses site preparation and…

  19. [A study on the local marriage network in Korea].

    Science.gov (United States)

    Kim, J S

    1987-12-01

    Place of residence has traditionally been an important factor in Korea in mate selection. This study examines the local marriage network in Korean society, its variation by year of marriage, and general characteristics of the married women. Data are drawn from the 1986 national sample survey on the family life cycle implemented by the Korea Institute for Population and Health. Questionnaires were administered to 3013 wives aged 15-64. Major study findings follow. 1) The local marriage rate within the same region by birthplace is strikingly high in Kyongsangdo and Chonla-do. Local marriage rates are 79.5% in both of these regions, 33.5% in Seoul, 35.2% in Busan, 50% in Kyonggi-do, 48.1% in Kangwon-do, and 60.7% in Chungchung-do. 2) The local marriage rate within the same county or the same city be residence before marriage has rapidly been declining in rural areas since 1960. This is largely due to industrialization, urbanization, and better transportation. The marriage rate in rural areas was 62% among marriages in the 1940s, 47.1% in the 1960s, 43% in the 1980s, and 70.9%, 88.4%, and 70.7% respectively in urban areas. 3) The proportion of local marriages within the same city or county is 55.1% among arranged marriages and 72.3% among romantic marriages. 4) Pre-marital employment seems to have some effects on the extent of mate-selection. Wives who worked before marriage were more likely to marry men in the same city or county. The local marriage rate within the same city or county is 63.2% among wives with work experience, and 58.5% among wives without work experience. 5) The more educated the woman, the higher the local marriage rate within the same city or county. 56.6% of those who attended middle school married men in the same city or county as theirs, 61.4% of wives with a high school education, and 76.6% of wives with college or more education. 63.8% of wives who never attended school married men in the same city or county. In summary, restrictions on

  20. Optimal computation of symmetric Boolean functions in Tree networks

    CERN Document Server

    Kowshik, Hemant

    2010-01-01

    In this paper, we address the scenario where nodes with sensor data are connected in a tree network, and every node wants to compute a given symmetric Boolean function of the sensor data. We first consider the problem of computing a function of two nodes with integer measurements. We allow for block computation to enhance data fusion efficiency, and determine the minimum worst-case total number of bits to be exchanged to perform the desired computation. We establish lower bounds using fooling sets, and provide a novel scheme which attains the lower bounds, using information theoretic tools. For a class of functions called sum-threshold functions, this scheme is shown to be optimal. We then turn to tree networks and derive a lower bound for the number of bits exchanged on each link by viewing it as a two node problem. We show that the protocol of recursive innetwork aggregation achieves this lower bound in the case of sumthreshold functions. Thus we have provided a communication and in-network computation stra...