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Partitioning networks into communities by message passing

Physical Review E 2011年第1期83卷 016115-016115页

作者： Darong Lai Christine Nardini Hongtao Lu MOE-Microsoft Laboratory for Intelligent Computing and Intelligent Systems Department of Computer Science and Engineering Shanghai Jiao Tong University 800 Dong Chuan Road 200240 Shanghai China

Community structures are found to exist ubiquitously in a number of systems conveniently represented as complex networks. Partitioning networks into communities is thus important and crucial to both capture and simplify these systems’ complexity. The prevalent and standard approach to meet this goal is related to the maximization of a quality function, modularity, which measures the goodness of a partition of a network into communities. However, it has recently been found that modularity maximization suffers from a resolution limit, which prevents its effectiveness and range of applications. Even when neglecting the resolution limit, methods designed for detecting communities in undirected networks cannot always be easily extended, and even less directly applied, to directed networks (for which specifically designed community detection methods are very limited). Furthermore, real-world networks are frequently found to possess hierarchical structure and the problem of revealing such type of structure is far from being addressed. In this paper, we propose a scheme that partitions networks into communities by electing community leaders via message passing between nodes. Using random walk on networks, this scheme derives an effective similarity measure between nodes, which is closely related to community memberships of nodes. Importantly, this approach can be applied to a very broad range of networks types. In fact, the successful validation of the proposed scheme on real and synthetic networks shows that this approach can effectively (i) address the problem of resolution limit and (ii) find communities in both directed and undirected networks within a unified framework, including revealing multiple levels of robust community partitions.

关键词： PARALLEL algorithms COMMUNITY organization WIRELESS sensor nodes MODULARITY (engineering) RANDOM walks (Mathematics)

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Guest editorial introduction to the special issue on citizen centered e-health systems in a global healthcare environment: Selected papers from ITAB 2009

Guest editorial introduction to the special issue on citizen...

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作者： Pattichis, Constantinos S. Schizas, Christos N. Kyriakou, Efthyvoulos C. Fotiadis, Dimitris I. Pattichis, Marios S. Bamidis, Panagiotis D. Department of Computer Science University of Cyprus 1678 Nicosia Cyprus Department of Computer Science and Engineering Frederick University Lemesos 3080 Cyprus Unit of Medical Technology and Intelligent Information Systems Department of Materials Science and Engineering University of Ioannina 45110 Ioannina Greece Department of Electrical and Computer Engineering University of New Mexico Albuquerque NM 87131 United States Laboratory of Medical Informatics Medical School Aristotle University of Thessaloniki Thessaloniki 54636 Greece

The January 2011 Special Issue of IEEE Transactions on Information Technology in Biomedicine includes selected papers from Information Technology in Biomedicine (ITAB 2009), held in the month of October in Cyprus. The overall objective of ITAB 2009 was to cover the state of the art in Information Technology Applications in Biomedicine, under the theme 'Citizen centered e-health systems in a global healthcare environment'. The Issue contains paper by Karagiannis and colleagues that investigates the performance of empirical mode decomposition (EMD) on ECGs. The paper by Stylianides introduces a novel, open source middleware framework for communication with medical devices and an application using the middleware named intensive care window (ICW). Cunningham and colleagues propose a home-based tool designed to monitor and assess peripheral motor symptoms. Loizou and colleagues introduce the use of multiscale AM FM texture analysis of multiple sclerosis (MS) using MR images from the brain.

关键词： Middleware

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Neighborhood-privacy protected shortest distance computing in cloud 11

Neighborhood-privacy protected shortest distance computing i...

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2011 ACM SIGMOD and 30th PODS 2011 Conference

作者： Gao, Jun Yu, Jeffrey Xu Jin, Ruoming Zhou, Jiashuai Wang, Tengjiao Yang, Dongqing Key Laboratory of High Confidence Software Technologies EECS Peking University Beijing China Department of Systems Engineering and Engineering Management Chinese University of Hong Kong Hong Kong Hong Kong Department of Computer Science Kent State University OH United States

ISBN: (纸本)9781450306614

With the advent of cloud computing, it becomes desirable to utilize cloud computing to efficiently process complex operations on large graphs without compromising their sensitive information. This paper studies shortest distance computing in the cloud, which aims at the following goals: i) preventing outsourced graphs from neighborhood attack, ii) preserving shortest distances in outsourced graphs, iii) minimizing overhead on the client side. The basic idea of this paper is to transform an original graph G into a link graph Gl kept locally and a set of outsourced graphs Go. Each outsourced graph should meet the requirement of a new security model called 1-neighborhood-d-radius. In addition, the shortest distance query can be answered using Gl and Go. Our objective is to minimize the space cost on the client side when both security and utility requirements are satisfied. We devise a greedy method to produce Gl and Go, which can exactly answer the shortest distance queries. We also develop an efficient transformation method to support approximate shortest distance answering under a given additive error bound. The final experimental results illustrate the effectiveness and efficiency of our method. © 2011 ACM.

关键词： Cloud computing

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Strong barrier coverage using directional sensors with arbitrarily tunable orientations

Strong barrier coverage using directional sensors with arbit...

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2011 7th International Conference on Mobile Ad-hoc and Sensor Networks, MSN 2011

作者： Tao, Dan Mao, Xu-Fei Tang, Shao-Jie Zhang, Hai-Tao Ma, Hua-Dong Xie, Hai-Jiang School of Electronic and Information Engineering Beijing Jiaotong University Beijing China Beijing Key Laboratory of Intelligent Telecomm. Software and Multimedia Beijing University of Posts and Telecomm. Beijing China Department of Computer Science Illinois Institute of Technology Chicago IL United States Department of Computer Science and Technology Xi'An JiaoTong University Xi'An China

ISBN: (纸本)9780769546100

Barrier coverage is an important problem for sensor networks to fulfill some given sensing tasks. Barrier coverage guarantees the detection of events happened crossing a barrier of sensors. In majority study of barrier coverage using sensor networks, sensors are assumed to have an isotropic sensing model. However, in many applications such as monitoring an area using video camera, the sensors have directional sensing model. In this paper, we investigate strong barrier coverage using directional sensors, where sensors have arbitrarily tunable orientations to provide good coverage. We investigate the problem of finding appropriate orientations of directional sensors such that they can provide strong barrier coverage. By exploiting geographical relations among directional sensors and deployment region boundaries, we first introduce the concept of virtual node to reduce the solution space from continuous domain to discrete domain. We then construct a directional barrier graph (DBG) to model this barrier coverage question such that we can quickly answer whether there are directional sensors' orientations that can provide strong barrier coverage over a given belt region. If the belt region is strong barrier covered, we then develop energy-efficient solutions to find strong barrier path(s) that will approximately minimize the total or the maximum rotation angles of all directional sensors. Extensive simulations are conducted to verify the effectiveness of our solution. © 2011 IEEE.

关键词： Sensor networks

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A Radial Basis Function Spike Model for Indirect Learning via Integrate-and-Fire Sampling and Reconstruction Techniques

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Advances in Artificial Neural systems 2012年第1期2012卷

作者： X. Zhang G. Foderaro C. Henriquez A. M. J. VanDongen S. Ferrari Laboratory for Intelligent Systems and Control (LISC) Department of Mechanical Engineering and Materials Science Duke University Durham NC 27708 USAduke.edu Department of Biomedical Engineering and Department of Computer Science Duke University Durham NC 27708 USAduke.edu Program in Neuroscience & Behavioral Disorders Duke-NUS Graduate Medical School Singapore Singapore

This paper presents a deterministic and adaptive spike model derived from radial basis functions and a leaky integrate-and-fire sampler developed for training spiking neural networks without direct weight manipulation. Several algorithms have been proposed for training spiking neural networks through biologically-plausible learning mechanisms, such as spike-timing-dependent synaptic plasticity and Hebbian plasticity. These algorithms typically rely on the ability to update the synaptic strengths, or weights, directly, through a weight update rule in which the weight increment can be decided and implemented based on the training equations. However, in several potential applications of adaptive spiking neural networks, including neuroprosthetic devices and CMOS/memristor nanoscale neuromorphic chips, the weights cannot be manipulated directly and, instead, tend to change over time by virtue of the pre- and postsynaptic neural activity. This paper presents an indirect learning method that induces changes in the synaptic weights by modulating spike-timing-dependent plasticity by means of controlled input spike trains. In place of the weights, the algorithm manipulates the input spike trains used to stimulate the input neurons by determining a sequence of spike timings that minimize a desired objective function and, indirectly, induce the desired synaptic plasticity in the network.

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NetworkCloudSim: Modelling Parallel Applications in Cloud Simulations

NetworkCloudSim: Modelling Parallel Applications in Cloud Si...

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IEEE International Conference on Utility and Cloud Computing (UCC)

作者： Saurabh Kumar Garg Rajkumar Buyya Cloud Computing and Distributed Systems (CLOUDS) Laboratory Department of Computer Science and Software Engineering University of Melbourne Australia

As interest in adopting Cloud computing for various applications is rapidly growing, it is important to understand how these applications and systems will perform when deployed on Clouds. Due to the scale and complexity of shared resources, it is often hard to analyze the performance of new scheduling and provisioning algorithms on actual Cloud test beds. Therefore, simulation tools are becoming more and more important in the evaluation of the Cloud computing model. Simulation tools allow researchers to rapidly evaluate the efficiency, performance and reliability of their new algorithms on a large heterogeneous Cloud infrastructure. However, current solutions lack either advanced application models such as message passing applications and workflows or scalable network model of data center. To fill this gap, we have extended a popular Cloud simulator (CloudSim) with a scalable network and generalized application model, which allows more accurate evaluation of scheduling and resource provisioning policies to optimize the performance of a Cloud infrastructure.

关键词： Computational modeling Data models Cloud computing Network topology Bandwidth Processor scheduling Virtual machining

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Resource Provisioning Policies to Increase IaaS Provider's Profit in a Federated Cloud Environment

Resource Provisioning Policies to Increase IaaS Provider's P...

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IEEE International Conference on High Performance Computing and Communications (HPCC)

作者： Adel Nadjaran Toosi Rodrigo N. Calheiros Ruppa K. Thulasiram Rajkumar Buyya Cloud Computing and Distributed Systems (CLOUDS) Laboratory Department of Computer Science and Software Engineering University of Melbourne Australia Department of Computer Science University of Manitoba Canada

Cloud Federation is a recent paradigm that helps Infrastructure as a Service (IaaS) providers to overcome resource limitation during spikes in demand for Virtual Machines (VMs) by outsourcing requests to other federation members. IaaS providers also have the option of terminating spot VMs, i.e, cheaper VMs that can be canceled to free resources for more profitable VM requests. By both approaches, providers can expect to reject less profitable requests. For IaaS providers, pricing and profit are two important factors, in addition to maintaining a high Quality of Service (QoS) and utilization of their resources to remain in the business. For this, a clear understanding of the usage pattern, types of requests, and infrastructure costs are necessary while making decisions to terminate spot VMs, outsourcing or contributing to the federation. In this paper, we propose policies that help in the decision-making process to increase resources utilization and profit. Simulation results indicate that the proposed policies enhance the profit, utilization, and QoS (smaller number of rejected VM requests) in a Cloud federation environment.

关键词： Outsourcing Quality of service Mathematical model Equations Pricing Computational modeling Availability

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Any 2⊗n subspace is locally distinguishable

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Physical Review A 2011年第1期84卷 012304-012304页

作者： Nengkun Yu Runyao Duan Mingsheng Ying []State Key Laboratory of Intelligent Technology and Systems Tsinghua National Laboratory for Information Science and Technology Department of Computer Science and Technology Tsinghua University Beijing 100084 China and Centre for Quantum Computation and Intelligent Systems (QCIS) Faculty of Engineering and Information Technology University of Technology Sydney NSW 2007 Australia

A subspace of a multipartite Hilbert space is said to be locally indistinguishable if any orthonormal basis of this subspace cannot be perfectly distinguished by local operations and classical communication. Previously it was shown that any m⊗n bipartite system with m>2 and n>2 has a locally indistinguishable subspace. However, it has been an open problem since 2005 whether there is a locally indistinguishable bipartite subspace with a qubit subsystem. We settle this problem in negative by showing that any 2⊗n bipartite subspace contains a basis that is locally distinguishable. As an interesting application, we show that any quantum channel with two Kraus operators has optimal environment-assisted classical capacity.

关键词： HILBERT space BANACH spaces BIPARTITE graphs GRAPH theory QUANTUM theory

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OPI model: A methodology for development metric based on outcome oriented

OPI model: A methodology for development metric based on out...

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International Joint Conference on computer science and software engineering (JCSSE)

作者： Kaenchan Thammarak Sarun Intakosum Software Systems Engineering Laboratory Department of Mathematics and Computer Science Faculty of Science King Mongkut's Institute of Technology Bangkok Thailand

Metric is extremely important for software development. It is a tool for measuring software in both quantitative and qualitative aspects. In addition, metric can be used for determining an achievement of the goals. There are some problems that bring difficulties to the design and development of software metrics. Among them, a number of software perspectives that metrics must handle and the way to apply metrics results to support business outcomes are considered important. This paper proposes OPI as a model for implementing software metrics based on business outcomes. There are three steps in this model, defining outcomes (O), defining perspectives (P), and defining indicators (I). A case study has been developed to assess the use of the proposed model. Forty undergraduate students, who have basic knowledge in software metric, use the model to develop metrics from the case study. The preliminary evaluation is based on usability aspect. The result has show that 85 percents of the students think that the model is easy to understand, where 8 and 7 percents say that it is moderate and hard respectively.

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QoS-aware Deployment of Network of Virtual Appliances Across Multiple Clouds

QoS-aware Deployment of Network of Virtual Appliances Across...

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IEEE International Conference on Cloud Computing Technology and science (CloudCom)

作者： Amir Vahid Dastjerdi Saurabh Kumar Garg Rajkumar Buyya Cloud Computing and Distributed Systems (CLOUDS) Laboratory Department of Computer Science and Software Engineering University of Melbourne Parkville VIC Australia

Cloud computing paradigm allows on-demand access to computing and storages services over the Internet. To solve the complexity of application deployment in Cloud infrastructure, virtual appliances, pre-configured, ready-to-run applications are emerging as a breakthrough technology. However, an automated approach for deploying network of appliances is required to guarantee minimum deployment cost, low latency, and high reliability. In this paper, we propose and compare two different deployment approaches: Forward-checking-based backtracking (FCBB) and genetic-based. They take into account Quality of Service (QoS) criteria such as reliability, data communication cost, and latency between multiple Clouds to choose the most appropriate combination of virtual machines and appliances. We evaluate our approach using a real case study and different request types. Experimental results show both algorithms reach near optimal solution. Further, we investigate effects of factors such as latency requirements, and data communication between appliances on the performance of the algorithms and placement of appliances across multiple Clouds.

关键词： Home appliances Quality of service Servers Monitoring Cloud computing Availability

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