ppxscal/embedding_network huggingface dataset:
Rapid Multipole Graph Drawing on the GPU
Authors: Apeksha Godiyal, Jared Hoberock, Michael Garland, John C. Hart
Venue: Graph Drawing: 16th International Symposium, GD 2008, Heraklion, Crete, Greece, September 21-24, 2008. Revised Papers (2009)

As graphics processors become powerful, ubiquitous and easier to program, they have also become more amenable to general purpose high-performance computing, including the computationally expensive task of drawing large graphs. This paper describes a new parallel analysis of the multipole method of graph drawing to support its efficient GPU implementation. We use a variation of the Fast Multipole Method to estimate the long distance repulsive forces in force directed layout. We support these multipole computations efficiently with a k-d tree constructed and traversed on the GPU. The algorithm achieves impressive speedup over previous CPU and GPU methods, drawing graphs with hundreds of thousands of vertices within a few seconds via CUDA on an NVIDIA GeForce 8800 GTX.
A Sampling Theory for Compact Sets in Euclidean Space
Authors: Fr&#x00e9;d&#x00e9;ric Chazal, David Cohen-Steiner, Andr&#x00e9; Lieutier
Venue: Discrete Computational Geometry (2009)

We introduce a parameterized notion of feature size that interpolates between the minimum of the local feature size and the recently introduced weak feature size. Based on this notion of feature size, we propose sampling conditions that apply to noisy samplings of general compact sets in euclidean space. These conditions are sufficient to ensure the topological correctness of a reconstruction given by an offset of the sampling. Our approach also yields new stability results for medial axes, critical points, and critical values of distance functions.
Oscillations of the Sending Window in Compound TCP
Authors: Alberto Blanc, Denis Collange, Konstantin Avrachenkov
Venue: Network Control and Optimization: Second Euro-NF Workshop, NET-COOP 2008 Paris, France, September 8-10, 2008. Revised Selected Papers (2009)

One of the key ideas of Compound TCP is to quickly increase the sending window, until full link utilization is detected, and then to keep it constant for a certain period of time. The actual Compound TCP algorithm does not hold the window constant but, instead, it makes it oscillate around the desired value. Using an analytical model and ns-2 simulations we study these oscillations on a Linux implementation of Compound TCP, in the case of a single connection with no cross traffic. Even in this simple case we show how these oscillations can behave in different ways depending on the bandwidth delay product. We also show how it is important to take into account, in the analytical model, that some implementation subtleties may introduce non-negligible differences in the behavior of the protocol.
On approximating four covering and packing problems
Authors: Mary Ashley, Tanya Berger-Wolf, Piotr Berman, Wanpracha Chaovalitwongse, Bhaskar DasGupta, Ming-Yang Kao
Venue: Journal of Computer and System Sciences (2009)

In this paper, we consider approximability issues of the following four problems: triangle packing, full sibling reconstruction, maximum profit coverage and 2-coverage. All of them are generalized or specialized versions of set-cover and have applications in biology ranging from full-sibling reconstructions in wild populations to biomolecular clusterings; however, as this paper shows, their approximability properties differ considerably. Our inapproximability constant for the triangle packing problem improves upon the previous results in [A. Caprara, R. Rizzi, Packing triangles in bounded degree graphs, Inform. Process. Lett. 84 (4) (2002) 175-180; J. Chlebikova, M. Chlebik, Complexity of approximating bounded variants of optimization problems, Theoret. Comput. Sci. 354 (3) (2006) 320-338]; this is done by directly transforming the inapproximability gap of Hastad for the problem of maximizing the number of satisfied equations for a set of equations over GF(2) [J. Hastad, Some optimal inapproximability results, in: Proc. of the 29th Annual ACM Symp. on Theory of Computing, 1997, pp. 1-10] and is interesting in its own right. Our approximability results on the full siblings reconstruction problems answers questions originally posed by Berger-Wolf et al. [T.Y. Berger-Wolf, B. DasGupta, W. Chaovalitwongse, M.V. Ashley, Combinatorial reconstruction of sibling relationships, in: Proc. of the 6th International Symposium on Computational Biology and Genome Informatics, 2005, pp. 1252-1255; T.Y. Berger-Wolf, S. Sheikh, B. DasGupta, M.V. Ashley, I. Caballero, W. Chaovalitwongse, S.L. Putrevu, Reconstructing sibling relationships in wild populations, Bioinformatics 23 (13) (2007) i49-i56] and our results on the maximum profit coverage problem provides almost matching upper and lower bounds on the approximation ratio, answering a question posed by Hassin and Or [R. Hassin, E. Or, A maximum profit coverage algorithm with application to small molecules cluster identification, in: 5th International Workshop Experimental Algorithms, in: Lecture Notes in Comput. Sci., vol. 4007, Springer-Verlag, 2006, pp. 265-276].
Nonasymptotic confidence sets of prescribed dimensions for parameters of nonlinear regressions
Authors: A. V. Timofeev
Venue: Automation and Remote Control (2009)

The article suggests the sequential plan for confidence estimation of multidimensional parameters that nonlinearly enter into the regression equation. The solution is obtained in the nonasymptotic statement under the condition of the incomplete prior definiteness relative to the distribution of heteroscedastic observations.
A Guide to SQL, 8th edition
Authors: Philip J. Pratt, Mary Z. Last
Venue:  (2008)

The author uses an interesting didactic innovation that every textbook writer should consider imitating: Instead of illustrating ideas with microprograms, which are good for almost nothing except illustrating the idea, Pratt develops two examples throughout the entire book. By the time you complete this thin but comprehensive volume, you will have completed two real databases. The book also contains embedded questions so you can check whether or not you've grasped specific concepts before proceeding to the next section. Pratt's extended case studies show how SQL programs can be layered on one another other to slowly build up functionality. As such, it serves both as an SQL language manual as well as an example of how to create relatively large SQL codes. This book does not make specific reference to any particular SQL implementation, so it can be used with any standard SQL engine.
Design of a maximum-likelihood detector for cooperative communications in intersymbol interference channels
Authors: Yanjie Peng, Andrew G. Klein, Xinming Huang
Venue: Proceedings of the 19th ACM Great Lakes symposium on VLSI (2009)

Recently, cooperative communication has attracted a lot of attention for its potential to increase spatial diversity. However, limited attention has been paid to the physical layer and implementation issues. In this paper, we investigate the feasibility of building optimal detectors for cooperative communications in intersymbol interference channels. A novel system model with the amplify-and-forward half-duplex relay is first introduced. Subsequently, we propose an optimal detector for receiver design which can be realized with a whitening filter and maximum likelihood sequence estimator (MLSE) based on the Viterbi algorithm. The implementation of the proposed detector is discussed, and its complexity is analyzed based on an FPGA implementation result. Numerical simulations demonstrating the performance of the detector are provided.
Design and implementation of distributed algorithms for WSN-based structural health monitoring
Authors: Miaomiao Wang, Jiannong Cao, Miao Liu, Bo Chen, Youlin Xu, Jing Li
Venue: International Journal of Sensor Networks (2009)

Wireless Sensor Networks (WSNs) have found many applications in a variety of ubiquitous computing environments. One of the key applications is Structural Health Monitoring (SHM) which seeks to monitor the functionality and detect the possible damages of large civil engineering structures, by measuring structural responses to ambient or forced excitation. WSNs are a promising new technology for SHM, but the contradicting considerations on the unique characteristics of WSNs and the inherent requirements of SHM pose challenges for practical implementation. Distributed processing in WSNs can help reduce energy consumption, make efficient use of network bandwidth and improve system response time. In this paper, we analyse the design issues of WSN-based SHM, and propose distributed processing architecture with algorithms. We also describe our system prototype built using Crossbow MICAz nodes and custom-made TFAD-901 super nodes. The performance of the proposed algorithms has been evaluated using various approaches. The results of the emulation study using the prototype system demonstrate the effectiveness of the proposed distributed processing approach. The results of laboratory testing and in-field experiments show the feasibility of practical deployment. Finally, the results of simulations enable us to gain insight of the distributed algorithms in large-scale systems.
A Bayesian Method for Decision of Weight for MADM Model with Interval Data
Authors: Sun Xuan, Niu Qinzhou, Xu Hefei
Venue: Proceedings of the 2009 International Conference on Advanced Computer Control (2009)

The weight in TOPSIS approach (technique for order preference by similarity ideal solution - TOPSIS ) is given by experts or decision makers. The value of weight would be influenced by experts’ subjective judgments. A slight difference in value of weight may result in diversity of order of alternatives. In this paper, a Bayesian method for decision of weight for MADM model with interval data is introduced. The value of weight is decided by prior information (other experts’ knowledge, or numerical simulation etc.) and experts’ knowledge (or decision makers’ experience/ preference). This method effectively takes advantage of experts’ knowledge and avoids the problem with experts’ subjectivity. An illustrative example is showed to explore the applications of proposed method. The method is valuable for field of multi-attribute decision- making with interval data.
Modeling and Key Technologies Study of Three-Stage Electro-Hydraulic Servo Valve
Authors: Xiaochu Liu, Jingfeng He, Zhengmao Ye, Dacheng Cong, Junwei Han
Venue: Proceedings of the 2009 International Asia Conference on Informatics in Control, Automation and Robotics (2009)

The modeling and study of three-stage electro-hydraulic servo valve are presented in this paper. According to its construction and principle, its model is built. The results of simulation and experimental test are consistent, which proves the validity of the model. Based on the study of the model, the performances of three-stage electro-hydraulic servo valve are mainly affected by pilot valve performance, spool and sleeve performance, position transducer performance and servo controller performance, which shows that there are four main key technologies. The study results have a guiding role for developing higher performance three-stage electro-hydraulic servo valve.
Analysis of spike-wave discharges in rats using discrete wavelet transform
Authors: Elif Derya íbeyli, Gül İlbay, Deniz Şahin, Nurbay Ateş
Venue: Computers in Biology and Medicine (2009)

A feature is a distinctive or characteristic measurement, transform, structural component extracted from a segment of a pattern. Features are used to represent patterns with the goal of minimizing the loss of important information. The discrete wavelet transform (DWT) as a feature extraction method was used in representing the spike-wave discharges (SWDs) records of Wistar Albino Glaxo/Rijswijk (WAG/Rij) rats. The SWD records of WAG/Rij rats were decomposed into time-frequency representations using the DWT and the statistical features were calculated to depict their distribution. The obtained wavelet coefficients were used to identify characteristics of the signal that were not apparent from the original time domain signal. The present study demonstrates that the wavelet coefficients are useful in determining the dynamics in the time-frequency domain of SWD records.
Inscription of information behaviour to communities of practice on an organisational intranet
Authors: Edin Tabak
Venue: Proceedings of the 20th Australasian Conference on Computer-Human Interaction: Designing for Habitus and Habitat (2008)

Organisational information systems could be more effective if users' information behaviour is inscribed to information systems. This paper describes inscriptions of information behaviour to three communities of practice on an organisational intranet and explores the impact of the inscriptions on the success of these communities from users' point of view. Seventeen participants from an entertainment organisation were interviewed using particular narrative technique - episodic interviewing. The due process model, based on actor-network theory, was used to select different actors and episodes from narratives and identify interactions between them. The study found that the most successful community of practice was the one that both successfully translated user information behaviour and aligned itself to important human (managers) and nonhuman (a product catalogue application) actors. Two unsuccessful applications either fail to successfully translate user information behaviour or fail to align itself to powerful actors.
Energy-aware and level-distribution routing protocol in ad hoc networks
Authors: Shi Zheng, Weiqiang Wu, Qinyu Zhang
Venue: Proceedings of the 2008 International Conference on Advanced Infocomm Technology (2008)

Energy resource is one of the most important resources in ad hoc networks where terminals are always supplied with limited energy. Recently, study on the strategy of saving energy and protecting lower energy nodes is attracting more and more attention. In this paper, energy-aware level-distribute (EALD)dynamic routing algorithm is introduced. Residual energy is divided into three levels, according to which, relevant algorithm of routing discovery is adopted. Load balance strategy in the whole network and protecting of lower energy nodes are well carry out. On the other hand, a large reduction of substitute routing discovery time is achieved because of remaining energy awareness and warning strategy in the routing maintenance. Compared with AODV protocol in various configurations of environment, simulation results show that this routing protocol prolongs the life time and releases the traffic load of the overused nodes.
Assessing descriptive substance in free-text collection-level metadata
Authors: Oksana Zavalina, Carole L. Palmer, Amy S. Jackson, Myung-Ja Han
Venue: Proceedings of the 2008 International Conference on Dublin Core and Metadata Applications (2008)

Collection-level metadata has the potential to provide important information about the features and purpose of individual collections. This paper reports on a content analysis of collection records in an aggregation of cultural heritage collections. The findings show that the free-text Description field often provides more accurate and complete representation of subjects and object types than the specified fields. Properties such as importance, uniqueness, comprehensiveness, provenance, and creator are articulated, as well as other vital contextual information about the intentions of a collector and the value of a collection, as a whole, for scholarly users. The results demonstrate that the semantically rich free-text Description field is essential to understanding the context of collections in large aggregations and can serve as a source of data for enhancing and customizing controlled vocabularies.
A Detachment Algorithm for Inferring a Graph from&#x00a0;Path Frequency
Authors: Hiroshi Nagamochi
Venue: Algorithmica (2009)

Inferring graphs from path frequency has been studied as an important problem which has a potential application to drug design and elucidation of chemical structures. Given a multiple set g of strings of labels with length at most&#x00a0;K, the problem asks to find a vertex-labeled graph&#x00a0;G that attains a one-to-one correspondence between g and the occurrences of labels along all paths of length at most K in G. In this paper, we prove that the problem with K=1 can be formulated as a problem of finding a loopless and connected detachment, based on which an efficient algorithm for solving the problem is derived. Our algorithm also solves the problem with an additional constraint such that every vertex in an inferred graph is required to have a specified degree.
UMTS LTE; Network, Services, Technologies, and Operation, 1st edition
Authors: Lawrence Harte, Carolyn Luck
Venue:  (2008)

This book explains the basic components, technologies used, and operation of UMTS LTE systems. You will discover why mobile telephone service providers are upgrading their 2nd and 3nd generation digital mobile to a more efficient and feature rich UMTS LTE generation system. Discover the key features that UMTS LTE systems provide that go beyond the capabilities of existing 2G and 3G mobile systems such as ultra high-speed Internet (100 Mbps+), television (multicast video), and low latency services (packet voice).Explained are the physical and logical radio channel structures of the UMTS LTE systems along with the basic frame and slot structures. Described are the fundamental capabilities and operation of the UMTS LTE radio channel including channel coding, modulation types, low-latency transmission and how transmission reliability is improved using MIMO technology.You will discover the key functional sections of UMTS LTE networks and how they communicate with each other. Learn how and why UMTS LTE systems separate control channels from user data channels. Learn how UMTS LTE systems can co-exist and interoperate with existing mobile systems and simplify the migration plan from less efficient mobile systems to more cost effective and capable UMTS LTE systems.Learn how spatial division multiple access (SDMA) can be used by UMTS LTE systems to provide dramatic increases in system capacity. The evolution of 3G systems into UMTS LTE systems explained. Some of the most important topics featured in this book are: How UMTS LTE systems operate UMTS LTE voice, data, and multimedia services The types of UMTS LTE products and their uses The UMTS LTE radio channel structure The different types of physical and logical channels UMTS LTE network components and interfaces Evolved multimedia broadcast multicast services (E-MBMS) Location bases services (LBS) IP multimedia subsystem (IMS) How UMTS LTE technology is evolving into 4G systems
Stereo Matching with Color-Weighted Correlation, Hierarchical Belief Propagation, and Occlusion Handling
Authors: Qingxiong Yang, Liang Wang, Ruigang Yang, Henrik Stewénius, David Nistér
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2009)

In this paper, we formulate a stereo matching algorithm with careful handling of disparity, discontinuity and occlusion. The algorithm works with a global matching stereo model based on an energy-minimization framework. The global energy contains two terms, the data term and the smoothness term. The data term is first approximated by a color-weighted correlation, then refined in occluded and low-texture areas in a {\it{repeated}} application of a hierarchical loopy belief propagation algorithm. The experimental results are evaluated on the Middlebury data sets, showing that our algorithm is the {\it{top}} performer among all the algorithms listed there.
Flow-Based Real-Time Communication in Multi-Channel Wireless Sensor Networks
Authors: Xiaodong Wang, Xiaorui Wang, Xing Fu, Guoliang Xing, Nitish Jha
Venue: Proceedings of the 6th European Conference on Wireless Sensor Networks (2009)

As many radio chips used in today's sensor mote hardware can work at different frequencies, several multi-channel communication protocols have recently been proposed to improve network throughput and reduce packet loss for wireless sensor networks. However, existing work cannot utilize multiple channels to provide explicit guarantees for application-specified end-to-end communication delays, which are critical to many real-time applications such as surveillance and disaster response. In this paper, we propose MCRT, a multi-channel real-time communication protocol that features a flow-based channel allocation strategy. Because of the small number of orthogonal channels available in current mote hardware, MCRT allocates channels to network partitions formed based on many-to-one data flows. To achieve bounded end-to-end communication delay for every data flow, the channel allocation problem has been formulated as a constrained optimization problem and proved to be NP-complete. We then present the design of MCRT, which includes a channel allocation algorithm and a real-time packet forwarding strategy. Extensive simulation results based on a realistic radio model demonstrate that MCRT can effectively utilize multiple channels to reduce the number of deadlines missed in end-to-end communications. Our results also show that MCRT outperforms a state-of-the-art real-time protocol and two baseline multi-channel communication schemes.
Intrusion Prevention in Depth System Research Based on Data Mining
Authors: Wang Jie, Zheng Xiao, Liu Yabin, Shi Chenghui
Venue: International Journal of Distributed Sensor Networks (2009)

This article proposes a data mining based intrusion prevention in depth system model to manage the huge amounts of unreliable and uncontrollable security events, which are generated by the extensive utilization of heterogeneous security devices in computer networks. A method of combining online detection and offline data mining is made use of as the core of the model. On the other hand, the work process of the system can be compartmentalized into two phases: online examination through pattern matching and offline training through data mining. By the online real-time data examination, the data are captured through the protocol analyzer at first, and then passed through the processor of regular rule set and parameters based detection engine. After corresponding processing to the data, the system can decide if the data should be stored and forwarded or an alarm management operation should be stimulated. By the offline data mining, the data preprocess module pretreats the data from various kinds of invasion and appraisal, and combines the mined knowledge to data that come from the compound detection engine and the policy making engine. The regular rule set is then updated and optimized through the new knowledge acquired by the offline data mining phase. The phases of online examination and offline data mining are executed alternatively and/or synchronously according to requirements of achieving optimal performance of the system. In our UPNSM, we unify the rule and the policy together to form the policy by the classified rule set and the human-computer interface and distribute policy to examination engines. This method provides our platform a better assistance to carry on various kinds of nimble effective operation. In fact, the model is a united network security management platform used to analyze the network and host data from different layers: the kernel layer, the concentration layer, and the access layer. Through enhancing the capture speed of the network data package, the proposed model can evidently improve the efficiency of traditional IPS for detection network intrusion. This verity can be demonstrated by simulation and experiment results. Thus, the proposed intrusion prevention in depth system model can be used for defense in real-time and defense in depth.