ppxscal/embedding_network huggingface dataset:
Functional Principal Component Learning Using Oja's Method and Sobolev Norms
Authors: Thomas Villmann, Barbara Hammer
Venue: Proceedings of the 7th International Workshop on Advances in Self-Organizing Maps (2009)

In this paper we present a method for functional principal component analysis based on the Oja-learning and neural gas vector quantizer. However, instead of the Euclidean inner product the Sobolev counterpart is applied, which takes the derivatives of the functional data into account and, therefore, uses information contained in the functional shape of the data into account. We investigate the theoretical foundations of the algorithm for convergence and stability and give exemplary applications.
Kernel Discriminant Analysis for Positive Definite and Indefinite Kernels
Authors: Elżbieta Pȩkalska, Bernard Haasdonk
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2009)

Kernel methods are a class of well established and successful algorithms for pattern analysis thanks to their mathematical elegance and good performance. Numerous nonlinear extensions of pattern recognition techniques have been proposed so far based on the so-called kernel trick. The objective of this paper is twofold. First, we derive an additional kernel tool that is still missing, namely kernel quadratic discriminant (KQD). We discuss different formulations of KQD based on the regularized kernel Mahalanobis distance in both complete and class-related subspaces. Secondly, we propose suitable extensions of kernel linear and quadratic discriminants to indefinite kernels. We provide classifiers that are applicable to kernels defined by any symmetric similarity measure. This is important in practice because problem-suited proximity measures often violate the requirement of positive definiteness. As in the traditional case, KQD can be advantageous for data with unequal class spreads in the kernel-induced spaces, which cannot be well separated by a linear discriminant. We illustrate this on artificial and real data for both positive definite and indefinite kernels.
An efficient algorithm for solving Hilbert type singular integral equations of the second kind
Authors: Zhong Chen, YongFang Zhou
Venue: Computers Mathematics with Applications (2009)

A simple and efficient method for solving Hilbert type singular integral equations of the second kind is given. In order to slide over the singularity of the equation, a transform is made. By improving the traditional reproducing kernel method, which requests that the image space of operator is W"2^1 and that the operator is bounded, the exact solution and the approximate solution of Hilbert type singular integral equations of the second kind are presented. The advantage of the approach lies in the fact that, on one hand, the approximate solution g"n(x) is continuous. On the other hand, g"n(x) and g"n^'(x) converge uniformly and rapidly to the exact solution g(x) and its derivatives g^'(x) respectively. Numerical experiments show the efficiency of our method.
Net negative charge in low-temperature SiO2 gate dielectric layers
Authors: A. Boogaard, A. Y. Kovalgin, R. A. M. Wolters
Venue: Microelectronic Engineering (2009)

SiO"2 gate dielectric layers (4-60nm) were grown (0.6nm/min) by plasma-enhanced chemical vapor deposition (PECVD) in strongly diluted silane plasmas at low substrate temperatures. In contrast to the well-accepted positive charge for thermally grown silicon dioxide, the net oxide charge was negative and a function of layer thickness. Our experiments suggested that the negative charge was created due to unavoidable oxidation of the silicon surface by plasma species, and the CVD component added a positive space charge to the deposited oxide. The net charge was negative under process conditions where plasma oxidation played a major role. Such conditions include low deposition rates and the growth of relatively thin layers.
QUAD: Quadrant-based relative location estimates for representative topologies in wireless sensor networks
Authors: May Wong, Demet Aksoy
Venue: Computer Networks: The International Journal of Computer and Telecommunications Networking (2009)

Sensor networks consist of devices that make various observations in the environment and communicate these observations to a central processing unit from where users can access collected data. In this regard, users' interpretation of collected data highly depends on the reported location of the sensor making an observation. GPS is an established technology to enable precise location information when deployed in open field. Yet, resource constraints and size issues prohibit its use in small sensor nodes that are designed to be cost-efficient. Instead, locations are estimated using a number of approaches. To date, however, the focus of such estimations was based on individual accuracy of sensor locations in isolation to the complete network. In this paper, we discuss problems with such approaches in terms of data management and analysis. We propose a novel location estimation algorithm called QUAD, quadrant-based localization, to enable representative topology information. In particular, QUAD makes use of relative distances from landmark points to determine the quadrant a node resides in and refines estimations according to neighbour provided information. QUAD makes use of uncertainty levels in estimates to further assist data analysis. Our experiment results suggest significant improvements in individual accuracy prior to optional refinements. Drastic improvements are achieved in the overall topology using refinements.
Computer science issues in high school: gender and more....
Authors: Judith Gal-Ezer, Daphna Shahak, Ela Zur
Venue: ACM SIGCSE Bulletin (2009)

Computer Science (CS) seems to be one of the few remaining disciplines almost entirely dominated by men, especially among university faculty and in the hi-tech industry. This phenomenon is prevalent throughout the western world. In Israel, we observed it in high schools where only 30% of the students who choose to major in CS are women. It continues in Israeli universities and colleges, where usually less than 30% of CS students are women. In this paper, we provide data describing the situation in Israeli high schools. In addition, we present a survey conducted among high school students which aimed, among other goals, to discover why girls did not choose to take CS in high school. We analyze the data and provide some conclusions and ways to deal with this situation.
A hybrid load balancing strategy of sequential tasks for grid computing environments
Authors: Yajun Li, Yuhang Yang, Maode Ma, Liang Zhou
Venue: Future Generation Computer Systems (2009)

Load balancing is of paramount importance in grid computing. Generally, load balancing can be categorised into two classes of activity based on the type of information on which the corresponding decisions are made, namely averages-based and instantaneous measures-based classes. Either class has certain flaws which confine themselves to limited performance improvement when being employed separately. It is therefore advantageous to combine both to form a hybrid one in order to make most of the strong points of each. In this paper, we address the load balancing problem by presenting a hybrid approach to the load balancing of sequential tasks under grid computing environments. Our main objective is to arrive at task assignments that could achieve minimum execution time, maximum node utilisation and a well-balanced load across all the nodes involved in a grid. A first-come-first-served and a carefully designed genetic algorithm are selected as representatives of both classes to work together to accomplish our goal. The simulation results show that our algorithm can achieve a better load balancing performance as compared to its 'pure' counterparts.
On Spanners of Geometric Graphs
Authors: Iyad A. Kanj
Venue: Proceedings of the 6th Annual Conference on Theory and Applications of Models of Computation (2009)

We consider the problem of computing spanners of Euclidean graphs embedded in the 2-dimensional Euclidean plane. We present an $O(n\lg{n})$ time algorithm that computes a spanner of a Euclidean graph that is of bounded degree and plane, where n is the number of points in the graph. Both upper bounds on the degree and the stretch factor significantly improve the previous bounds. We extend this algorithm to compute a bounded-degree plane lightweight spanner of a Euclidean graph.Our results rely on elegant structural and geometric results that we develop. Moreover, our results can be extended to Unit Disk graphs under the local distributed model of computation.
An adaptive feedback controller for SIP server memory overload protection
Authors: Yixin Diao, Xiaolei Hu, Asser Tantawi, Haishan Wu
Venue: Proceedings of the 6th international conference on Autonomic computing (2009)

Memory overload is one of the key challenges in managing enterprise application server performance such as in J2EE environment. Realizing this issue, J2EE middleware providers introduced management solutions to prevent memory overload. However, such solutions depend on configurable parameters, such as thread pool size and queue length limit, which are typically difficult to determine and unaccommodating to application behavioral changes. In this paper we introduce a dynamic memory overload protection solution based on applying adaptive feedback controller techniques. Our solution consists of (1) a model that captures the dynamics of system and workload characteristics, (2) a Kalman filter for model parameter estimation, and (3) an adaptive feedback controller that regulates the load admission rate to the server in order to prevent memory overload. In particular, we have designed and implemented a self-configurable memory overload controller, which is automatically tuned based on an analytical model of the system under control. We conducted experiments where we used our controller prototype to manage a commercially available SIP server and compared it to a static, fixed gain feedback controller. Our experimental results show that, with little configuration effort, the adaptive controller reacts nicely to workload dynamics.
Analog fault detection and classification using genetic algorithm
Authors: Reza Askari Moghadam
Venue: Proceedings of the international conference on Computational and information science 2009 (2009)

The increased complexity of recent integrated circuits and Micro Electro Mechanical Systems (MEMS) production requires a significant effort in testing that has to keep pace with this progress in circuit and system design in order to ensure their quality and reliability. Thus a powerful tool or method is needed to detect different faults in MEMS devices. In MEMS, electrical, mechanical, electromagnetical and other nonelectrical parts are used and multi domain energies are usually converted to electrical signals. Because of complexity and microscopic material properties, there are a wide range of analog and digital faults. Nowadays, we have not a comprehensive science of microscopic fault mechanisms and most of them are analog faults which are difficult to be detected. Artificial Intelligence (AI) methods seemed to be a good candidate for fault detection. In this paper a new Genetic Algorithm (GA) is proposed for good classification of patterns and distinguishing fault free and faulty clusters. Different formulas have been used to calculate Closeness and evaluation function of patterns.
Challenges for assuring quality of service in a service-oriented environment
Authors: Sriram Balasubramaniam, Grace A. Lewis, Ed Morris, Soumya Simanta, Dennis B. Smith
Venue: Proceedings of the 2009 ICSE Workshop on Principles of Engineering Service Oriented Systems (2009)

Service-oriented architecture (SOA) has become an increasingly popular mechanism for achieving business agility and reuse. However, organizations implementing SOA-based solutions are facing new implementation challenges related to validation and verification activities in an SOA environment, especially of runtime system quality attributes such as interoperability, security, reliability, and performance. This position paper presents some of these challenges.
A multi-agent self-adaptative management framework
Authors: E. Lavinal, T. Desprats, Y. Raynaud
Venue: International Journal of Network Management (2009)

The self-management vision, which has raised much interest in recent years, is only an operational aim that does not provide any solution in its definition on how to attain this management autonomy. The general contribution of this article suggests concepts, methods and mechanisms to conceive a self-adaptative management framework, thus participating in this self-management vision. This framework is composed of organizational aspects based on multi-agent concepts, informational aspects based on different management ontologies and cooperative aspects based on specific agent behaviours which automate the accomplishment of management actions on the overall distributed environment. We have also implemented a prototype of this work to validate the feasibility of our approach and confirm the self-adaptation capacities of the system.
Experimental Analysis of Oscillatory Airflow in a Bronchiole Model with Stenosis
Authors: J-K. Kim, M. Kawahashi, H. Hirahara, Y. Iwasaki
Venue: Journal of Visualization (2009)

As the mechanism of gas transport and exchange in human respiratory ventilation, the complicated processes of mixing and diffusion in airways of human lungs are considered. However the mechanism has not been clarified enough. On the other hand, the analysis of detailed mechanism in the case of artificial ventilation like HFOV (High Frequency Oscillatory Ventilation) is strongly required for the development of clinical treatments on patients with respiration disorder. In HFOV, it is considered that pendelluft becomes one of the important factors of gas transport and exchange because of high frequency ventilation in comparison with natural breathing. As increase of the frequency, the different time constants of lung units generate phase lag of ventilation in airways of lungs. The phase lag of ventilation causes to generate pendelluft. The time constant is determined by compliance and flow resistance of lung unit. In order to investigate the effect of the different time constants induced by the difference of flow resistance in a part of respiratory bronchiole of human lungs, the experimental study has been carried out by using multi-bifurcated micro channels as a model of bronchiole. The flow resistance in the model channels was produced by a stenosis. The velocity distributions of ventilation flows in the channels with and without the stenosis have been measured by using &mu;-PIV technique. The results obtained show the frequency effects on the flow pattern in the bronchiole model channels and the appearance of pendelluft.
Possibilistic pattern recognition in a digestive database for mining imperfect data
Authors: Anas Dahabiah, John Puentes, Basel Solaiman
Venue: WSEAS TRANSACTIONS on SYSTEMS (2009)

We propose in this paper a method based, on the one hand, on possibility theory to calculate the similarity among the objects of any casebase, taking into account the imperfection and the heterogeneity of data, and based, on the other hand, on the geometric models like the linear and the circular unidimensional scaling and on the graphic models like the ultrametric trees in order to represent and to visualize this similarity in such a way that we can explore and discover the potential structures and patterns that exist in the data. This approach will be applied to an endoscopic casebase in order to recognize the lesions and the pathologies of this base, and several concrete examples will be given along the paper in order to clarify the mathematical concepts of the method.
Influence of Tree Topology Restrictions on the Complexity of Haplotyping with Missing Data
Authors: Michael Elberfeld, Ilka Schnoor, Till Tantau
Venue: Proceedings of the 6th Annual Conference on Theory and Applications of Models of Computation (2009)

Haplotyping, also known as haplotype phase prediction, is the problem of predicting likely haplotypes from genotype data. One fast haplotyping method is based on an evolutionary model where a perfect phylogenetic tree is sought that explains the observed data. Unfortunately, when data entries are missing as is often the case in laboratory data, the resulting incomplete perfect phylogeny haplotyping problem ipph is NP-complete and no theoretical results are known concerning its approximability, fixed-parameter tractability, or exact algorithms for it. Even radically simplified versions, such as the restriction to phylogenetic trees consisting of just two directed paths from a given root, are still NP-complete; but here a fixed-parameter algorithm is known. We show that such drastic and ad hoc simplifications are not necessary to make ipph fixed-parameter tractable: We present the first theoretical analysis of an algorithm, which we develop in the course of the paper, that works for arbitrary instances of ipph. On the negative side we show that restricting the topology of perfect phylogenies does not always reduce the computational complexity: while the incomplete directed perfect phylogeny problem is well-known to be solvable in polynomial time, we show that the same problem restricted to path topologies is NP-complete.
A Strategic Approach for Re-organizing the Internet Topology by Applying Social Behavior Dynamics
Authors: Yasuhiro Sato, Shingo Ata, Ikuo Oka
Venue: Journal of Network and Systems Management (2009)

Recent studies have described the topologies of various networks including the Internet are categorized as scale-free networks. Scale-free network is extremely vulnerable to node attacks. However, the suitability of the topology of the Internet for communications has not been studied. We investigate whether the current Internet is optimized in both aspects of communication efficiency and attack tolerance. For this, we define three metrics to represent the capabilities of the network, which are Clustering coefficient, Efficiency, and Reachability. As a result, we found that the value of ¿, a scaling exponent in power law function representing the degree distribution of a scale-free network, may be reduced in the present Internet. To reduce the value of ¿, we propose four strategies for re-organizing a network. However, in real network, we cannot control the user's preference directly. We use a diffusion model based on social behavior dynamics. Furthermore, we show the characteristics of the re-organized networks, and discuss which strategy is more appropriate for achieving a desired network.
An empirical study of constraint logic programming and answer set programming solutions of combinatorial problems
Authors: Agostino Dovier, Andrea Formisano, Enrico Pontelli
Venue: Journal of Experimental Theoretical Artificial Intelligence (2009)

This paper presents experimental comparisons between the declarative encodings of various computationally hard problems in Answer Set Programming (ASP) and Constraint Logic Programming over Finite Domains (CLP(FD)). The objective is to investigate how solvers in the two domains respond to different problems, highlighting the strengths and weaknesses of their implementations, and suggesting criteria for choosing one approach over the other. Ultimately, the work in this paper is expected to lay the foundations for a transfer of technology between the two domains, for example by suggesting ways to use CLP(FD) in the execution of ASP.
From agent interaction protocols to executable code: a model-driven approach
Authors: Christian Hahn, Ingo Zinnikus, Stefan Warwas, Klaus Fischer
Venue: Proceedings of The 8th International Conference on Autonomous Agents and Multiagent Systems - Volume 2 (2009)

In this paper, we demonstrate how to design protocols with the platform independent modeling language for multiagent systems (Dsml4mas) and discuss a model-driven approach to use protocol descriptions as a base for generating the corresponding agent behaviors which can finally be executed with Jack Intelligent Agents.
A novel technique for the direct determination of multimode equivalent circuit models for substrate integrated waveguide discontinuities
Authors: Maurizio Bozzi, Luca Perregrini, Ke Wu
Venue: International Journal of RF and Microwave Computer-Aided Engineering (2009)

A novel technique is presented for the automatic, self-consistent and direct determination of wide-band lumped-element equivalent circuit models of substrate integrated waveguide discontinuities. This technique is based on the full-wave analysis of substrate integrated waveguide components by using the Boundary Integral-Resonant Mode Expansion method, which provides a generalized admittance matrix of the components in the form of a pole expansion in the frequency domain. This expression of the admittance matrix permits to directly identify the topology of a multimodal equivalent circuit and the values of its lumped elements, thus avoiding any initial guess or fitting procedure. The basic theory of the full-wave analysis method and the procedure for determining the equivalent circuit model are reported. The features of the proposed technique are detailed through the modeling of an iris-like discontinuity. Moreover, this technique is validated by modeling substrate integrated waveguide filters, whose frequency response is compared with numerical and experimental results. The proposed method can be adopted to obtain libraries of parametric models of substrate integrated waveguide discontinuities, which can be included in computer aided design tools. The multimodal parametric model of an iris-like discontinuity is presented and discussed. &copy; 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.
An automated testing experiment for layered embedded C code
Authors: Boutheina Chetali, Quang-Huy Nguyen
Venue: International Journal on Software Tools for Technology Transfer (STTT) (2009)

This paper describes an experiment using an automated tool for testing smart cards embedded software developed in C. Conventional testing of smart cards uses low-level commands and writing the use cases and test scripts is an error-prone and tedious task. Our goal was to show how one can use a formal tool to improve the testing process in order to concentrate better on the efficiency of the test. The approach consists in modeling each layer of the system independently while abstracting the services provided by the lower layers. The model is then verified, simulated and test cases are automatically generated using test criteria such as reachable state coverage and transition coverage. We also developed a translator to execute those test cases on the C implementation of the system. We show the results obtained and the lessons learned from the application of this approach to the validation phase of a smart cards file system manager.