ppxscal/embedding_network huggingface dataset:
Numerical solution for the wave equation
Authors: M. F. Patricio
Venue: International Journal of Computer Mathematics (2009)

In this paper we study numerical solutions for a hyperbolic system of equations using finite differences. In this setting, we propose the method of lines, with high precision in space. A class of some explicit, implicit and also semi-implicit schemes, with code variable methods, are presented. Finally, the analysis of some qualitative and quantitative proprieties of these methods is included.
Elimination of Disjunction and Negation in Answer-Set Programs under Hyperequivalence
Authors: Jörg Pührer, Hans Tompits, Stefan Woltran
Venue: Proceedings of the 24th International Conference on Logic Programming (2008)

The study of different notions of equivalence is one of the cornerstones of current research in answer-set programming. This is mainly motivated by the needs of program simplification and modular programming, for which ordinary equivalence is insufficient. A recently introduced equivalence notion in this context is hyperequivalence, which includes as special cases strong, uniform, and ordinary equivalence. We study in this paper the question of replacing programs by syntactically simpler ones preserving hyperequivalence (we refer to such a replacement as a casting). In particular, we provide necessary and sufficient semantic conditions under which the elimination of disjunction, negation, or both, in programs is possible, preserving hyperequivalence. In other words, we characterise in model-theoretic terms when a disjunctive logic program can be replaced by a hyperequivalent normal, positive, or Horn program, respectively. Furthermore, we study the computational complexity of the considered tasks and, based on similar results for strong equivalence developed in previous work, we provide methods for constructing the respective hyperequivalent programs. Our results contribute to the understanding of problem settings in logic programming in the sense that they show in which scenarios the usage of certain constructs are superfluous or not.
Generalization performance of support vector machines and neural networks in runoff modeling
Authors: Mohsen Behzad, Keyvan Asghari, Morteza Eazi, Maziar Palhang
Venue: Expert Systems with Applications: An International Journal (2009)

Effective one-day lead runoff prediction is one of the significant aspects of successful water resources management in arid region. For instance, reservoir and hydropower systems call for real-time or on-line site-specific forecasting of the runoff. In this research, we present a new data-driven model called support vector machines (SVMs) based on structural risk minimization principle, which minimizes a bound on a generalized risk (error), as opposed to the empirical risk minimization principle exploited by conventional regression techniques (e.g. ANNs). Thus, this stat-of-the-art methodology for prediction combines excellent generalization property and sparse representation that lead SVMs to be a very promising forecasting method. Further, SVM makes use of a convex quadratic optimization problem; hence, the solution is always unique and globally optimal. To demonstrate the aforementioned forecasting capability of SVM, one-day lead stream flow of Bakhtiyari River in Iran was predicted using the local climate and rainfall data. Moreover, the results were compared with those of ANN and ANN integrated with genetic algorithms (ANN-GA) models. The improvements in root mean squared error (RMSE) and squared correlation coefficient (R^2) by SVM over both ANN models indicate that the prediction accuracy of SVM is at least as good as that of those models, yet in some cases actually better, as well as forecasting of high-value discharges.
e-governance in rural India
Authors: Deepthi Shanker
Venue: Proceedings of the 2nd International Conference on Theory and Practice of Electronic Governance (2008)

E-governance initiatives in India have been crucial developmental activities undertaken in the recent years. Karnataka state in India has been foremost in implementing many of such e-governance related developmental projects. The paper in progress is an attempt to debate and explore the application of e-governance projects and policies in Indian situation. Implementation and functioning of the some of the e-governance policies and projects at the grass root levels in rural India are considered.
Asymptotic distributions of robust shape matrices and scales
Authors: Gabriel Frahm
Venue: Journal of Multivariate Analysis (2009)

It has been frequently observed in the literature that many multivariate statistical methods require the covariance or dispersion matrix @S of an elliptical distribution only up to some scaling constant. If the topic of interest is not the scale but only the shape of the elliptical distribution, it is not meaningful to focus on the asymptotic distribution of an estimator for @S or another matrix @C@K@S. In the present work, robust estimators for the shape matrix and the associated scale are investigated. Explicit expressions for their joint asymptotic distributions are derived. It turns out that if the joint asymptotic distribution is normal, the estimators presented are asymptotically independent for one and only one specific choice of the scale function. If it is non-normal (this holds for example if the estimators for the shape matrix and scale are based on the minimum volume ellipsoid estimator) only the scale function presented leads to asymptotically uncorrelated estimators. This is a generalization of a result obtained by Paindaveine [D. Paindaveine, A canonical definition of shape, Statistics and Probability Letters 78 (2008) 2240-2247] in the context of local asymptotic normality theory.
Numerical Analysis of Chinese Economy in an Small Scale RBC Model: 1996-2005
Authors: Li Li, Yang Liu
Venue: Proceedings of the 2009 International Conference on Advanced Computer Control (2009)

This paper uses a version of Hansen's (1985) Real Business Cycle (RBC) model to mimic Chinese business cycle from 1996 to 2005. The comparison of simulation results and actual data implies that the model can reflect economic fluctuations. Quantitative analysis demonstrates that technology shock contributes to more than 90.3% of Chinese economic fluctuations, and RBC model is an ideal framework for Chinese economy policy analysis. The paper also suggests to incorporate a wider set of state variable, such as monetary, fiscal, and oil price shocks to improve the performance of the model.
A succinct memory model for automated design debugging
Authors: Brian Keng, Hratch Mangassarian, Andreas Veneris
Venue: Proceedings of the 2008 IEEE/ACM International Conference on Computer-Aided Design (2008)

In today's complex SoC designs, verification and debugging are becoming ever more crucial and increasingly time-consuming tasks. The prevalence of embedded memories adds to the difficulty of the problem by exponentially increasing the statespace of the design. In this work, a novel memory model for design debugging is presented. It models memory succinctly by avoiding an explicit representation for each memory bit. The method uses the simulation of the erroneous design to guide the debugging process. This results in a parameterizable formal encoding that grows linearly with the erroneous trace length, significantly reducing the memory requirements of the debugging problem. In addition, the proposed model is extended to handle an arbitrary initial memory configuration, as well as non-cycle accurate output traces where only a final expected memory state is available for comparison. Experiments on industrial designs show a 96% average reduction in memory usage along with a noticeable performance improvement compared to previous work.
Energy-based selective cluster-head rotation in wireless sensor networks
Authors: Feng Ming Hu, Yun Ho Kim, Kyung Tae Kim, Hee Yong Youn, Chang Won Park
Venue: Proceedings of the 2008 International Conference on Advanced Infocomm Technology (2008)

In wireless sensor networks energy-efficiency is a big challenge due to the limited battery power of sensor nodes. Using a localized chain structure and one cluster-head, PEGASIS (Power-Efficient Gathering in Sensor Information System) achieves significant improvement over the existing protocols like LEACH. In this paper we propose EBSCR (Energy-Based Selective Cluster-head Rotation) protocol, which further enhances PEGASIS. It does not change the cluster-head every round to reduce the energy consumption caused by cluster-head rotation. Simulation results show that the lifetime of the nodes with EBSCR is extended about 20% compared to that of PEGASIS.
KDGT: Knowledge Discovery in Game Theory
Authors: Ganesh Kumar. M, Anoop Sunke, Ganesh. S, Avinesh. D
Venue: Proceedings of the 2009 Second International Workshop on Knowledge Discovery and Data Mining (2009)

Games have been used with astounding success to describe diverse situations where one or more entities (players) interact with each other according to various rules. As the concept is encompassing, it is very flexible and that is the reason why applications range from the social sciences and economics to biology and mathematics or computer science. This makes the game theoretic computation very complicated. This research work presents a frame work which integrates Game Theory with Data Mining. Due to enormous amount of data, it is hard for Game Theory alone to perform the modeling analysis. Data mining assists Game Theory to deal with the large amount of data and finds hidden rules to improve game analysis.
Queueing models for single machine manufacturing systems with interruptions
Authors: Kan Wu, Leon F. McGinnis, Bert Zwart
Venue: Proceedings of the 40th Conference on Winter Simulation (2008)

Queueing theory is a well-known method for evaluating the performance of manufacturing systems. When we want to analyze the performance of a single machine, M/M/1 queues or approximations of G/G/1 queues often are considered a proper choice. However, due to the complex nature of interruptions in manufacturing, the appropriate model should be selected carefully. This paper proposes a systematic way to classify different kinds of interruptions seen in a single machine system. Queueing models for each category are proposed, and event classifications are compared from both the SEMI E10 and queueing theory points of view.
Multirate adaptive filtering for low complexity DS/CDMA code acquisition
Authors: Hua-Lung Yang, Wen-Rong Wu
Venue: Signal Processing (2009)

Code acquisition in CDMA systems is conventionally conducted with a matched-filter based structure. However, the performance of this method degrades greatly while multiple access interference presents. Recently, an adaptive filtering scheme was proposed to solve this problem. It has been shown that the computational complexity of this approach is proportional to the delay uncertainty and inversely proportional to the required acquisition time. When propagation delay is large and the required acquisition time is short, the computational complexity of the adaptive filtering approach will become high. In this paper, we propose a multirate adaptive code acquisition approach to alleviate this problem. The proposed scheme is comprised of several acquisition units operating in different processing rates. Thanks to the decimation property in multirate processing, the overall computational complexity can be greatly reduced. Theoretical analysis of adaptive filters and mean acquisition time is also provided. Experimental results show that while the proposed scheme can have comparable performance with respect to the original adaptive acquisition scheme, its computational complexity is much lower.
iManage: policy-driven self-management for enterprise-scale systems
Authors: Vibhore Kumar, Brian F. Cooper, Greg Eisenhauer, Karsten Schwan
Venue: Proceedings of the ACM/IFIP/USENIX 2007 International Conference on Middleware (2007)

It is obvious that big, complex enterprise systems are hard to manage. What is not obvious is how to make them more manageable. Although there is a growing body of research into system self-management, many techniques are either too narrow, focusing on a single component rather than the entire system, or not robust enough, failing to scale or respond to the full range of an administrator's needs. In our iManage system we have developed a policy-driven system modeling framework that aims to bridge the gap between manageable components and manageable systems. In particular, iManage provides: (1) system state-space partitioning, which divides a large system state-space into partitions that are more amenable to constructing system models and developing policies, (2) online model and policy adaptation to allow the self-management infrastructure to deal gracefully with changes in operating environment, system configuration, and workload, and (3) tractability and trust, where tractability allows an administrator to understand why the system chose a particular policy and also influence that decision, and trust allows an administrator to understand the system's confidence in a proposed, automated action. Simulations driven by scenarios given to us by our industrial collaborators demonstrate that iManage is effective both at constructing useful system models and in using those models to drive automated system management.
Computing Best and Worst Shortcuts of Graphs Embedded in Metric Spaces
Authors: Jun Luo, Christian Wulff-Nilsen
Venue: Proceedings of the 19th International Symposium on Algorithms and Computation (2008)

Given a graph embedded in a metric space, its dilation is the maximum over all distinct pairs of vertices of the ratio between their distance in the graph and the metric distance between them. Given such a graph G with n vertices and m edges and consisting of at most two connected components, we consider the problem of augmenting G with an edge such that the resulting graph has minimum dilation. We show that we can find such an edge in $O((n^4\log n)/\sqrt m)$ time using linear space which solves an open problem of whether a linear-space algorithm with o(n 4) running time exists. We show that O(n 2logn) time is achievable if G is a simple path or the union of two vertex-disjoint simple paths. Finally, we show how to find an edge that maximizes the dilation of the resulting graph in O(n 3) time with O(n 2) space and in O(n 3logn) time with linear space.
Using forward reachability analysis for verification of timed petri nets
Authors: Parosh Aziz Abdulla, Johann Deneux, Pritha Mahata, Aletta Nylén
Venue: Nordic Journal of Computing (2007)

We consider verification of safety properties for concurrent real-timed systems modelled as timed Petri nets by performing symbolic forward reachability analysis. We introduce a formalism, called region generators, for representing sets of markings of timed Petri nets. Region generators characterize downward closed sets of regions and provide exact abstractions of sets of reachable states with respect to safety properties. We show that the standard operations needed for performing symbolic reachability analysis are computable for region generators. Since forward reachability analysis is necessarily incomplete, we introduce an acceleration technique to make the procedure terminate more often on practical examples. We have implemented a prototype for analyzing timed Petri nets and used it to verify a parameterized version of Fischer's protocol, Lynch and Shavit's mutual exclusion protocol and a producer-consumer protocol. We also used the tool to extract finite-state abstractions of these protocols.
Adversarial queuing theory with setups
Authors: M. Kiwi, M. Soto, C. Thraves
Venue: Theoretical Computer Science (2009)

We look at routing and scheduling problems on Kelly type networks where the injection process is under the control of an adversary. The novelty of the model we consider is that the adversary injects requests of distinct types. Resources are subject to switch-over delays or setups when they begin servicing a new request class. In this new setting, we study the behavior of sensible policies as introduced by Dai and Jennings [J. Dai, O. Jennings, Stabilizing queueing networks with setups, Math. Oper. Res. (2004) 891-922]. We first show that the model is robust in the sense that under some mild conditions universal stability of work conserving packet routing protocols is preserved for natural variants of the underlying model. Also, the model's equivalence to so called token networks is established. We adapt to the multi-type request and setup setting, standard arguments for proving stability. Nevertheless, we provide counterexamples that show that for several reasonable adaptations of contention resolution protocols to the multi-type case, stability results do not carry over from the single-type scenario. This motivates us to explore fluid model based arguments that could be used for proving stability for a given network. Specifically we show analogues of results obtained by Gamarnik [D. Gamarnik, Stability of adversarial queues via fluid model, in: Proc. of the 39th Annual Symposium on Foundations of Computer Science, 1998, pp. 60-70] but in the multi-type request with setups scenario.
Efficient identification of starters and followers in social media
Authors: Michael Mathioudakis, Nick Koudas
Venue: Proceedings of the 12th International Conference on Extending Database Technology: Advances in Database Technology (2009)

Activity and user engagement in social media such as web logs, wikis, online forums or social networks has been increasing at unprecedented rates. In relation to social behavior in various human activities, user activity in social media indicates the existence of individuals that consistently drive or stimulate 'discussions' in the online world. Such individuals are considered as 'starters' of online discussions in contrast with 'followers' that primarily engage in discussions and follow them. In this paper, we formalize notions of 'starters' and 'followers' in social media. Motivated by the challenging size of the available information related to online social behavior, we focus on the development of random sampling approaches allowing us to achieve significant efficiency while identifying starters and followers. In our experimental section we utilize BlogScope, our social media warehousing platform under development at the University of Toronto. We demonstrate the scalability and accuracy of our sampling approaches using real data establishing the practical utility of our techniques in a real social media warehousing environment.
An architecture for linking medical decision-support applications to clinical databases and its evaluation
Authors: Efrat German, Akiva Leibowitz, Yuval Shahar
Venue: Journal of Biomedical Informatics (2009)

We describe and evaluate a framework, the Medical Database Adaptor (MEIDA), for linking knowledge-based medical decision-support systems (MDSSs) to multiple clinical databases, using standard medical schemata and vocabularies. Our solution involves a set of tools for embedding standard terms and units within knowledge bases (KBs) of MDSSs; a set of methods and tools for mapping the local database (DB) schema and the terms and units relevant to the KB of the MDSS into standardized schema, terms and units, using three heuristics (choice of a vocabulary, choice of a key term, and choice of a measurement unit); and a set of tools which, at runtime, automatically map standard term queries originating from the KB, to queries formulated using the local DB's schema, terms and units. The methodology was successfully evaluated by mapping three KBs to three DBs. Using a unit-domain matching heuristic reduced the number of term-mapping candidates by a mean of 71% even after other heuristics were used. Runtime access of 10,000 records required one second. We conclude that mapping MDSSs to different local clinical DBs, using the three-phase methodology and several term-mapping heuristics, is both feasible and efficient.
Cooperative Shot Boundary Detection for Video
Authors: Shaohua Teng, Wenwei Tan, Wei Zhang
Venue: Computer Supported Cooperative Work in Design IV: 11th International Conference, CSCWD 2007, Melbourne, Australia, April 26-28, 2007. Revised Selected Papers (2008)

Video Shot boundary detection is a fundamental task in any kind of video content analysis and retrieval. Meaningful segments, such as cut or gradual transition, will be found by performing a boundary detection task. This task has already become an important part of the work on TRECVID. In this paper, we propose a general approach for shot boundary detection. We adopt cooperative model to decide whether a shot transition exists within a given video sequence. Such an approach is beneficial for multiple tasks and is carried out through a group of detection agents, which enables the agents to cooperate and be charged with detection task. By fusing detection results of agents, more precise detection effect is obtained. We demonstrate the power of our approach on the TRECVID-2005 benchmarking platform and the experimental results reveal the effectiveness of the proposed method.
Modeling Attention and Perceptual Grouping to Salient Objects
Authors: Thomas Geerinck, Hichem Sahli, David Henderickx, Iris Vanhamel, Valentin Enescu
Venue: Attention in Cognitive Systems: 5th International Workshop on Attention in Cognitive Systems, WAPCV 2008 Fira, Santorini, Greece, May 12, 2008 Revised Selected Papers (2009)

In this paper, we propose a biologically inspired model of the middle stages of attention, with specific algorithmic details. Existing computational models of attention concentrate on their role in visual feature extraction and the selection of spatial regions. However, these methods ignore the role of attention in other stages. Extension of these models has been proposed by augmenting the unit of attentional selection to "proto-objects". In our approach, we extend attention to the middle stages and integrate the selection process with the perceptual grouping process. Integration is achieved by our innovative saliency driven perceptual grouping strategy, extending the traditional pixel-based saliency map to salient proto-objects. The proposed selective attention is made in two stages. Firstly, to achieve salient region localization, our method enhances the saliency map with region information from image segmentation and selects the most salient region (proto-object). Then, regions are organized using perceptual groupings, and their pop-out sequence is determined. Compared with traditional attention models our model provides saliency maps with meaningful region information, by eliminating misleading high-contrast edges, and focus of attention shifts in unit of perceptual object rather than spatial region. These two improvements fit to high stage vision information processing such as object recognition. Experiments in a reduced set of images show that our proposed model is able to automatically detect meaningful proto-objects.
Selecting Creativity Techniques for Innovative Requirements Engineering
Authors: Per Pascal Grube, Klaus Schmid
Venue: Proceedings of the 2008 Third International Workshop on Multimedia and Enjoyable Requirements Engineering - Beyond Mere Descriptions and with More Fun and Games (2008)

While the traditional focus of requirements engineering was mainly on the systematic, reliable and adequate translation of the customers intentions into requirements documentation, it became recently increasingly accepted that requirements engineering, especially for innovative and novel products, is probably more adequately described as a process of joint discovery of requirements that can be supported by creativity techniques. However, so far little work exists on how to systematically select techniques as a basis for requirements engineering. As part of the IdSpace Project, which focuses on collaborative product innovation, we are currently investigating this area. This paper provides a brief overview of our work in this domain.