ppxscal/embedding_network huggingface dataset:
Efficient structured policies for admission control in heterogeneous wireless networks
Authors: Amin Farbod, Ben Liang
Venue: Mobile Networks and Applications (2007)

In the near future, demand for heterogeneous wireless networking (HWN) is expected to increase. QoS provisioning in these networks is a challenging issue considering the diversity in wireless networking technologies and the existence of mobile users with different communication requirements. In HWNs with their increased complexity, "the curse of dimensionality" problem makes it impractical to directly apply the decision theoretic optimal control methods that are previously used in homogeneous wireless networks to achieve desired QoS levels. In this paper, optimal call admission control policies for HWNs are considered. A decision theoretic framework for the problem is derived by a dynamic programming formulation. We prove that for a two-tier wireless network architecture, the optimal policy has a two-dimensional threshold structure. Further, this structural result is used to design two computationally efficient algorithms, Structured Value Iteration and StructuredUpdate Value Iteration. These algorithms can be used to determine the optimal policy in terms of thresholds. Although the first one is closer in its operation to the conventional Value Iteration algorithm, the second one has a significantly lower complexity. Extensive numerical observations suggest that, for all practical parameter sets, the algorithms always converge to the overall optimal policy. Further, the numerical results show that the proposed algorithms are efficient in terms of time-complexity and in achieving the optimal performance.
Automatic package and board decoupling capacitor placement using genetic algorithms and M-FDM
Authors: Krishna Bharath, Ege Engin, Madhavan Swaminathan
Venue: Proceedings of the 45th annual Design Automation Conference (2008)

In the design of complex power distribution networks (PDN) with multiple power islands, it is required that the PDN represents a low impedance as seen by the digital modules. This is to reduce the simultaneous switching noise (SSN), generated due to the switching activity of digital drivers. Typically this reduction in impedance is accomplished by placing decoupling capacitors between the power and ground planes of a package or board. However, the performance of the decoupling solution is a function of capacitor selection and its placement. In this paper, an automatic capacitor placement optimization method has been proposed. This method relies on a genetic algorithm to provide a stochastic search of the design space, while employing an efficient core PDN simulator based on the multi-layer finite difference method (M-FDM). The technique has been employed to show optimized placements for split planes as well as for a realistic multi-layer server board.
Brief paper: A method for optimal control and filtering of multitime-scale linear singularly-perturbed stochastic systems
Authors: N. Prljaca, Z. Gajic
Venue: Automatica (Journal of IFAC) (2008)

In this paper we introduce a transformation for the exact closed-loop decomposition of the optimal Kalman filter and the linear quadratic optimal controller of multi time scale continuous-time, linear, singularly-perturbed stochastic systems. The solution of the corresponding algebraic regulator and filter Riccati equations are obtained in terms of solutions of reduced-order subsystem, algebraic, Riccati equations corresponding to the system time scales. We have also obtained N completely independent reduced-order subsystem Kalman filters working in parallel in different time scales. This allows parallel processing of information with lower-order, different rates Kalman filters consistent with the system time scales.
PTO: A Trust Ontology for Pervasive Environments
Authors: Mohsen Taherian, Rasool Jalili, Morteza Amini
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications - Workshops (2008)

Traditionally, to handle security for stand-alone computers and small networks, user authentication and access control mechanisms would be almost enough. However, considering distributed networks such as the Internet and pervasive environments, these kinds of approaches confront with flexibility challenges and scalability problems. This is mainly because of that open environments lack a central control, and users in them are not predetermined. In such ubiquitous computing environments, issues concerning security and trust become crucial. Adding trust to the existing security infrastructures would enhance the security of these environments. Although many trust models have been proposed to deal with trust issues in pervasive environments, none of them considered the semantic relations among pervasive elements and specially among trust categories. Employing Semantic Web concepts, we propose a computational trust model based on the ontology structure, considering the mentioned semantic relations. In this model, each entity can calculate its trust about other entities and use the calculated trust values to make decisions about granting or rejecting interactions. The use of ontology structure can make the model extendible to encompass other pervasive features such as context awareness in a simple way.
Performance Optimization for Multi-agent Based Simulation in Grid Environments
Authors: Dawit Mengistu, Peter Tröger
Venue: Proceedings of the 2008 Eighth IEEE International Symposium on Cluster Computing and the Grid (2008)

Multi-agent based simulation (MABS) is a discrete event simulation technique used to study complex systems with entities having social and autonomous behavior. MABS applications are characterized by unpredictable execution behavior and high communication-to-computation ratio. In this paper, we propose an adaptation strategy to support efficient execution of large-scale MABS applications on typical Grid infrastructures. To achieve this objective, the behavior of MABS applications and the execution environment is investigated, in order to constantly obtain performance prediction models. These models will then be used to realize dynamic load balancing and resource allocation schemes. We discuss our basic approach, initial experimental results, the planned future research and an application of our research in the transportation and logistics simulation domain.
Inverting the Viterbi algorithm: an abstract framework for structure design
Authors: Michael Schnall-Levin, Leonid Chindelevitch, Bonnie Berger
Venue: Proceedings of the 25th international conference on Machine learning (2008)

Probabilistic grammatical formalisms such as hidden Markov models (HMMs) and stochastic context-free grammars (SCFGs) have been extensively studied and widely applied in a number of fields. Here, we introduce a new algorithmic problem on HMMs and SCFGs that arises naturally from protein and RNA design, and which has not been previously studied. The problem can be viewed as an inverse to the one solved by the Viterbi algorithm on HMMs or by the CKY algorithm on SCFGs. We study this problem theoretically and obtain the first algorithmic results. We prove that the problem is NP-complete, even for a 3-letter emission alphabet, via a reduction from 3-SAT, a result that has implications for the hardness of RNA secondary structure design. We then develop a number of approaches for making the problem tractable. In particular, for HMMs we develop a branch-and-bound algorithm, which can be shown to have fixed-parameter tractable worst-case running time, exponential in the number of states of the HMM but linear in the length of the structure. We also show how to cast the problem as a Mixed Integer Linear Program.
Font recognition of Chinese character based on multi-scale wavelet
Authors: Jiacai Fu, Mingliang Guo, Xianglong Tang
Venue: Proceedings of the 5th WSEAS International Conference on Circuits, Systems, Electronics, Control & Signal Processing (2006)

Optical character recognition system research has been acquired howling success, but the reconstruction of layout needs fonts of the characters. In this paper, a novel font recognition algorithm is proposed, which is based on multi-scale wavelet analysis. We adopt wavelet analysis and the grid method to deal with the character image, and extract wavelet energy density feature, and apply the BP Neural Network to classify the different fonts. The experiments show that the font recognition of Chinese character based on multi-scale wavelet analysis algorithm can effectively recognize the 4 kinds of the Chinese characters.
An Efficient Algrithm To Find All 'Bidirectional' Edges Of An Undirected Graph
Authors: B. Mishra
Venue: Proceedings of the 25th Annual Symposium onFoundations of Computer Science, 1984 (1984)

An efficient algorithm for the All-Bidirectional-Edges Problem is presented. The All-Bidirectional-Edges Problem is to find an edge-labelling of an undirected network, G = (V,E), with a source and a sink, such that an edge [u,v] /spl epsi/ E is labelled (u,v) or (v,u) (or both) depending on the existence of a (simple) path from the source to sink that visits the vertices u and v, in the order u,v or v,u, respectively. The algorithm presented works by partitioning the graph into a set of bridges and analyzing them recursively. The time complexity of the algorithm is shown to be O(\E\ . \V\). The problem arises naturally in the context of the simulation of in MOS transistor network, in which a transistor may operate as a unilateral or a bilateral device, depending on the voltages at its source and drain nodes. For efficient simulation, it is required to detect the set of transistors that may operate as bilateral devices. Also, this algorithm can be used in order to detect all the sneak paths in a network of pass transistor. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
ArmSim: A Complete System Simulation Environment of the ARM Embedded System
Authors: Wan Han, Gao Xiaopeng
Venue: Proceedings of the Fifth International Conference on Information Technology: New Generations (2008)

This paper proposes a basic ARM full system simulation environment, on which one can run and debug system or user-level programs. It has flexible software architecture and good encapsulation. We implemented a remote debugging system based on our simulation kernel, which extends remote serial protocol (RSP) of GDB and using Eclipse as the front-UI to build a platform-independent system. These provide benefits to embedded system study, o.s. development, and application performance tuning.
Root Cause Analysis Using Sequence Alignment and Latent Semantic Indexing
Authors: R. P. Jagadeesh Chandra Bose, U. Suresh
Venue: Proceedings of the 19th Australian Conference on Software Engineering (2008)

Automatic identification of software faults has enormous practical significance. This requires characterizing program execution behavior. Equally important is the aspect of diagnosing (finding root-cause of) faults encountered. In this article, we address the problem of identifying the root cause of failure from the test sequences that caused failure. Taking analogies from biological sequence alignment and information retrieval domains we propose two approaches for finding the root cause of failure. The first approachis to align all the test sequences pertaining to a fault and identifying the common pattern among these sequences. The other approach is based on an information retrieval technique viz., the latent semantic indexing (LSI). Our experiments and analysis showed that the sequence alignment based approach has the potential to aid significantly in identifying the root cause of failure. The LSI based approach automatically clusters the test sequences based on their functionality, which assists in determining the different manifestations of a fault.
Software: Hero or Zero?
Authors: Robert L. Glass
Venue: IEEE Software (2008)

People might love to support underdogs, but they also love to kick them when they're down. And, at this point in time at least, software is the world's technological underdog!
New method for the precise flux calculation of neutrals for arbitrary surfaces in profile etch simulations
Authors: M. Hauguth, T. Danz, B. E. Volland, V. Ishshuk, D. Dreíler, I. W. Rangelow
Venue: Microelectronic Engineering (2008)

A method for precise neutral flux calculation inside etched features based on a finite element method is presented. This new method yields exact results and is suitable for arbitrary profile shapes at acceptable execution speed. The model parameters are the sticking coefficients of the neutral species to the different sample materials. The model is verified against systematic plasma etching experiments of silicon.
Optimistic load balancing in a distributed virtual environment
Authors: Roman Chertov, Sonia Fahmy
Venue: Proceedings of the 2006 international workshop on Network and operating systems support for digital audio and video (2006)

Distributed virtual environments such as massive multi-player games require multiple servers to balance computational load. This paper investigates the architecture of a unified environment where the virtual online world is not partitioned according to rigid boundaries, but according to an adaptive paradigm. Since it is difficult to develop an optimal load balancing algorithm for a unified environment, we propose an optimistic scheme that quickly converges. The cost of frequent migrations is reduced by following a push/push data exchange model. We analyze the computational time costs of such a system and give simulation results to gauge its performance. The simulation results confirm that our load balancing scheme is efficient and can support large numbers of clients.
Parallel association rule mining based on FI-growth algorithm
Authors: Bundit Manaskasemsak, Nunnapus Benjamas, Arnon Rungsawang, Athasit Surarerks, Putchong Uthayopas
Venue: Proceedings of the 13th International Conference on Parallel and Distributed Systems - Volume 01 (2007)

Association rule mining is one of the most important techniques in data mining. It extracts significant patterns from transaction databases and generates rules used in many decision support applications. Many organizations such as industrial, commercial, or even scientific sites may produce large amount of transactions and attributes. Mining effective rules from such large volumes of data requires much time and computing resources. In this paper, we propose a parallel FI-growth association rule mining algorithm for rapid extraction of frequent itemsets from large dense databases. We also show that this algorithm can efficiently be parallelized in a cluster computing environment. The preliminary experiments provide quite promising results, with nearly ideal scaling on small clusters and about half of ideal (15 fold speedup) on a thirty-two processor cluster.
Distributed delays stabilize neural feedback systems
Authors: Ulrike Meyer, Jing Shao, Saurish Chakrabarty, Sebastian F. Brandt, Harald Luksch, Ralf Wessel
Venue: Biological Cybernetics (2008)

We consider the effect of distributed delays in neural feedback systems. The avian optic tectum is reciprocally connected with the isthmic nuclei. Extracellular stimulation combined with intracellular recordings reveal a range of signal delays from 3 to 9&#x00a0;ms between isthmotectal elements. This observation together with prior mathematical analysis concerning the influence of a delay distribution on system dynamics raises the question whether a broad delay distribution can impact the dynamics of neural feedback loops. For a system of reciprocally connected model neurons, we found that distributed delays enhance system stability in the following sense. With increased distribution of delays, the system converges faster to a fixed point and converges slower toward a limit cycle. Further, the introduction of distributed delays leads to an increased range of the average delay value for which the system&#x2019;s equilibrium point is stable. The system dynamics are determined almost exclusively by the mean and the variance of the delay distribution and show only little dependence on the particular shape of the distribution.
A Tribute to Jim Gray
Authors: Eric Allman
Venue: Queue (2008)

Computer science attracts many very smart people, but a few stand out above the others, somehow blessed with a kind of creativity that most of us are denied. Names such as Alan Turing, Edsger Dijkstra, and John Backus come to mind. Jim Gray is another.
Modeling and experimental chromatographic measurements in adsorption
Authors: F. Roubani-Kalantzopoulou
Venue: Proceedings of the 1st WSEAS International Conference on Computational Chemistry (2007)

Reversed-flow inverse gas chromatography is extended to the experimental measurements of the probability density function for the adsorption energies as well as the differential energies of adsorption due to lateral interactions of molecules adsorbed on different heterogeneous solid surfaces. Thus, useful scientific information concerning the nature and the strength of the adsorbate-adsorbent and adsorbate-adsorbate interactions have been extracted in order to give appropriate answers to the questions: (a) Where are the molecules on the heterogeneous surface and (b) Which is the nature of the surface chemical bonds? The solids studied as adsorbents are the oxides of Calcium, Magnesium, Phosphorous and the adsorbates used hydrocarbons C2 -C4 as well as Ozone. The exponential stripping method of the PC program, used to calculate the necessary exponential coefficients of time is guided by the overall goodness of fit expressed by the square of correlation coefficient r2. This coefficient is always in the range 0.990 - 0.999 showing a remarkable goodness of fit for a non-linear regression analysis. The programs also print, together with the exponential coefficients values, their standard errors, which were reasonable enough for physicochemical measurements.
A Practical Multi-channel Media Access Control Protocol for Wireless Sensor Networks
Authors: Hieu Khac Le, Dan Henriksson, Tarek Abdelzaher
Venue: Proceedings of the 7th international conference on Information processing in sensor networks (2008)

Despite availability of multiple orthogonal communication channels on common sensor network platforms, such as MicaZ motes, and despite multiple simulation-supported designs of multi-channel MAC protocols, most existing sensor networks use only one channel for communication, which is a source of bandwidth inefficiency. In this work, we design, implement, and experimentally evaluate a practical MAC protocol which utilizes multiple channels efficiently for WSNs. A control theory approach is used to dynamically allocate channels for each mote in a distributed manner transparently to the application and routing layers. The protocol assumes that sensor nodes are equipped with one half-duplex radio interface which is most common in current hardware platforms. The protocol does not require time synchronization among nodes and takes the channel switching cost of current hardware into account. Evaluation results on a real testbed show that it achieves a non-trivial bandwidth improvement using 802.15.4 radios in topologies which are typical in WSNs. The MAC protocol was implemented in TinyOS-2.x and packaged as a software component to enable seamless use with existing applications.
Mapping Genetic Influences on Brain Shape Using Multi-Atlas Fluid Image Alignment
Authors: Meena Mani, Yi-yu Chou, Natasha Leporé, Agatha Lee, Jan de Leeuw, Katie McMahon, Margie Wright, Arthur Toga, Paul M. Thompson
Venue: Proceedings of the 2007 Frontiers in the Convergence of Bioscience and Information Technologies (2007)

In this pilot study, we developed a set of computer vision based surface segmentation and statistical shape analysis algorithms to study genetic influences on brain structure in a database of brain MRI scans of normal twins. A set of manually delineated 3D parametric surfaces, representing the lateral ventricles, was deformed, using a Navier-Stokes fluid image registration algorithm, onto all the images in the database. The geometric transformations thus obtained were used to propagate the segmentation labels to all the other images. 3D radial distance maps were derived to encode anatomical shape differences. The proportion of shape variance attributable to genetic factors, known as the heritability, was estimated from the shape models using a restricted maximum likelihood method to increase statistical power. Segmentation errors associated with projecting labels onto new images were greatly reduced through multi-atlas averaging. The resulting algorithms provide a convenient and sensitive tool to recover and analyze small intrapair image differences, and will make it easier to detect genetic influences on brain structure.
Optimal Number of Replicas with QoS Assurance in Data Grid Environment
Authors: Yasser Mansouri, Reza Monsefi
Venue: Proceedings of the 2008 Second Asia International Conference on Modelling & Simulation (AMS) (2008)

Optimizing the use of grid resources is critical for users to effectively exploit a Data Grid (DG). Data replication is considered as a major technique for increasing access performance and data availability in DG systems. Current works on data replications in Grid systems focuses on infrastructure for replication mechanism for creating or deleting replicas. One of the challenges in data replication is determining Optimal Number of Replicas (ONR) with Quality of Service (QoS) assurance, as well as their Optimal Location of Replicas (OLR) in DG.In this paper, we propose an algorithm that finds ONR of an object over DG systems, such that the overall communication and storage cost is minimized. This algorithm ensures that QoS required from the users are satisfied. In addition, we proposed a sketch of the proof for our algorithm and its integrity.
The concept of decentralized and secure electronic marketplace
Authors: Constantin Serban, Yingying Chen, Wenxuan Zhang, Naftaly Minsky
Venue: Electronic Commerce Research (2008)

For commerce (electronic or traditional) to be effective, there must be a degree of trust between buyers and sellers. In traditional commerce, this kind of trust is based on such things as societal laws and customs, and on the intuition people tend to develop about each other during interpersonal interactions. The trustworthiness of these factors is based, to a large extent, on the geographical proximity between buyers and sellers. But this proximity is lost in e-commerce.In conventional electronic marketplaces the trust among participants is supported by a central server which imposes certain trading rules on all transactions. But such centralized marketplaces have serious drawbacks, among them: lack of scalability, and high cost.In this paper we propose the concept of Decentralized Electronic Marketplace (DEM) which allow buyers and sellers to engage in commercial transactions, subject to an explicitly stated set of trading rules, called the law of this marketplace--which they can trust to be observed by their trading partners. This trust is due to a decentralized, and thus scalable, mechanism that enforces the stated law of the DEM. We implement an electronic marketplace for airline tickets in order to illustrate the feasibility of the proposed concepts for decentralized and secure electronic marketplace.