ppxscal/embedding_network huggingface dataset:
Modified relaxation time Monte Carlo method for continuum-transition gas flows
Authors: Xudong Lan, Jun Sun, Zhixin Li
Venue: Journal of Computational Physics (2008)

Gas flows in the continuum-transition regime often occur in micro-electro-mechanical systems. The relaxation time Monte Carlo (RTMC) method was modified by using an ellipsoid statistical model and a multiple translational temperature model in the BGK model equation to simulate continuum-transition gas flows. The modified RTMC method uses a simplified form of the generalized relaxation time, which is related to the macro velocity and the local Knudsen number. The results for Couette flow and Poiseuille flow in microchannels predicted using the modified RTMC and the DSMC are in good agreement with the modified RTMC being much faster than the DSMC for continuum-transition gas flow simulations.
Simulation of Parallel Resonance Condition in Electrical Network Using EDSA
Authors: Kamlesh K. Wadhwani
Venue: Proceedings of the Tenth International Conference on Computer Modeling and Simulation (2008)

This paper covers the effects of parallel resonance in the Electrical Network due to Power Factor correction (PFC)/VAR compensation. Parallel Resonance can make entire electrical network unstable as THD (voltage) may rise upto 26% of fundamental (which is nearly seven to eight times of THD produced by the harmonic source) resulting in highly distorted Electrical wave. This will result in misfiring in UPS, Variable Frequency Drives, and Battery Charges. The Protection system may mal-operate due to resonance. The losses in various electrical equipments will increase, which will result in heating and ultimately premature failure of equipments. A typical Electrical network was modeled in EDSA (Electrical design software) and parallel resonance condition was simulated to analyze the effect of resonance on following:• THD on various busses in the electrical network • Impedance response with/without the PFC • Distortion of waveform at various buses • Corrective measures to avoid resonance due to PFC
Infrastructure for ubiquitous services
Authors: Athman Bouguettaya
Venue: Proceedings of the nineteenth conference on Australasian database - Volume 75 (2008)

Services science is slowly gaining acceptance in both industry and academia as the necessary vehicle to introduce large scale efficiencies in service economies that are now predominant in most developed and many developing countries. The development of service-oriented computing was the computing research community's response to the emerging multidisciplinary field of services science. Service-oriented computing aims at providing a foundational computing framework to support a service-centric approach to solve the vexing problems of integration and interoperability. The Web is and will undoubtedly be the preferred delivery platform of targeted solutions. More specifically, Web services are poised to be the key component of the service-oriented approach for the efficient management of services on the Web. Fully delivering on the potential of next-generation Web services requires building a foundation that would provide a sound design for efficiently developing, deploying, publishing, discovering, composing, and optimizing access to Web services. The proposed Web service foundation will enable the development of a uniform framework called Web Service Management System that would be to Web services what DBMSs have been to data. In this framework, Web services would be treated as first-class objects that can be manipulated as if they were pieces of data. In this talk, I will first motivate the need for WSMSs. I will then overview our own research work developing the foundation of the core components of WSMSs which include: Web service query optimization, Web service composition, Web service change management, and Web service trust management. Finally, I will overview an E-government WSMS prototype that has been used as a deployment test-bed.
A novel circuit element and its application in signal amplification
Authors: Stephan J. G. Gift, Brent Maundy
Venue: International Journal of Circuit Theory and Applications (2008)

A novel IC-based current amplifier configuration for signal-processing applications that can be configured using commercially available integrated circuit elements is presented. The circuit is accurate, has a wide bandwidth and can drive grounded loads. It utilizes a CCII+ type current conveyor with its input circuit in the feedback loop of a current feedback amplifier (CFA). In the current amplifying mode, the circuit has a low input impedance over a broad frequency range which never rises above the low input impedance of the inverting input of the associated CFA. Experimental results obtained using AD844s confirm the results derived. Copyright &copy; 2007 John Wiley & Sons, Ltd.
Fast and Robust Analytical Design of Equiripple Comb FIR Filters for Communication Purposes
Authors: Pavel Zahradnik, Boris imák, Miroslav Vlcek
Venue: Proceedings of the Seventh International Conference on Networking (2008)

A novel analytical design method for highly selective digital optimal equiripple comb FIR filters is presented. The equiripple comb FIR filters are optimal in the Chebyshev sense. The number of notch bands, the width of the notch bands and the attenuation in the pass bands can be independently specified. The degree formula and the differential equation for the generating polynomial of the filter is presented. Based on the differential equation, a fast simple algebraic recursive procedure for the evaluation of the impulse response of the filter is described. Its arithmetic robustness outperforms by far the known analytical design method. Highly selective equiripple comb FIR filters with thousands of coefficients can be designed. One example demonstrates the efficiency of the filter design.
A Project-based Assessment for Introductory Bioinformatics Course - An Assessment Aimed to Reinforce Students' Ability in Data Analyses Interpretation and Integration
Authors: Lynn Farh, Shyan-Jer Lee
Venue: Proceedings of the 2008 International Conference on BioMedical Engineering and Informatics - Volume 02 (2008)

Analyses, interpretation and integration of the information are the high level cognition skills, and mastering these knowledge integration skills is the main goal of science education. We’ve employed a project-based assessment to facilitate such learning in a bioinformatics course. This assessment is presented as a set of designed assignments, which is based on a protein sequence with unidentified function. A series of criteria have been formulated to serve as the learning scaffold for students. The criteria are intended to foster the students’ ability in tool selection, data analyses and output interpretation. In the second stage, the students in group of three are asked to integrate and explore their results to construct a research-oriented project. The project is displayed in a poster format and reviewed by experts and peers. Through this process, students successfully demonstrate their achievement in choosing tools, interpreting data, integrating results, building new models, and formulating testable hypothesis.
A novel approach in objective assessment of functional postural responses during fall-free perturbed standing in clinical environment
Authors: Imre Cikajlo, Zlatko Matjačsić
Venue: Technology and Health Care (2007)

The proposed approach offers few novelties in integration of objective assessment of postural responses when an unexpected perturbation is applied to the standing person into the existing rehabilitation therapy. The research apparatus was equipped with electrical actuators to provide unexpected perturbations (controllable and repeatable strength and duration) to the standing frame in eight directions during quiet standing in a fall-safe environment. During the perturbations ground reaction forces were recorded under each foot and the motion of center of pressure was derived to extract the postural response indicators in time and space domain. Seven neurologically intact subjects participated in normative set up that was used to develop an algorithm for selective postural response characteristics analysis for each perturbation direction. The postural responses in two incomplete spinal cord injured persons and hemiparetic stroke patient were investigated and contrasted to the normative responses to test the proposed approach. The outcomes of the investigation showed expected distinctive direction-dependent postural responses characteristic for hemiparetic subjects. Our observations suggest that the approach may become effective in substantial quantitative multidirectional stabilometric evaluation of functional postural responses, especially when the effectiveness of the balance training rehabilitation program is in need for objective evaluation. Simultaneously the apparatus can be used also for the balance training and therefore become a training and assessment tool for clinical and home environment.
Improving Startup Performance for a Medical Image Viewing Application
Authors: Yang-Ming Zhu, Madhavi Ahuja, Xiangyu Wu, Chris Dauterman, Cheng-Hsiu Chen, Ron Sukalac, Steve Cochoff
Venue: IT Professional (2008)

Combining information from various medical imaging modalities can lead to better diagnoses, treatment planning, and results assessment. If it is done carelessly, it can lead to poor application start-up performance and cause bottlenecks. The authors developed a medical-imaging-viewing application with C# and the .NET Framework. For a typical use scenario, the start-up time was about 40 seconds. To tackle the sluggish start-up, the authors analyzed the application to understand the bottleneck and determine where the time was spent. Using various techniques, they reduced the start-up time to about seven seconds, greatly improving customer satisfaction.
Real-Time Path Planning in Dynamic Virtual Environments Using Multiagent Navigation Graphs
Authors: Avneesh Sud, Erik Andersen, Sean Curtis, Ming C. Lin, Dinesh Manocha
Venue: IEEE Transactions on Visualization and Computer Graphics (2008)

We present a novel approach for efficient path planning and navigation of multiple virtual agents in complex dynamic scenes. We introduce a new data structure, Multi-agent Navigation Graph (MaNG), which is constructed using first- and second-order Voronoi diagrams. The MaNG is used to perform route planning and proximity computations for each agent in real time. Moreover, we use the path information and proximity relationships for local dynamics computation of each agent by extending a social force model [Helbing05]. We compute the MaNG using graphics hardware and present culling techniques to accelerate the computation. We also address undersampling issues and present techniques to improve the accuracy of our algorithm. Our algorithm is used for real-time multi-agent planning in pursuit-evasion, terrain exploration and crowd simulation scenarios consisting of hundreds of moving agents, each with a distinct goal.
Portfolios with fuzzy returns: Selection strategies based on semi-infinite programming
Authors: Enriqueta Vercher
Venue: Journal of Computational and Applied Mathematics (2008)

This paper provides new models for portfolio selection in which the returns on securities are considered fuzzy numbers rather than random variables. The investor's problem is to find the portfolio that minimizes the risk of achieving a return that is not less than the return of a riskless asset. The corresponding optimal portfolio is derived using semi-infinite programming in a soft framework. The return on each asset and their membership functions are described using historical data. The investment risk is approximated by mean intervals which evaluate the downside risk for a given fuzzy portfolio. This approach is illustrated with a numerical example.
Forced large amplitude periodic vibrations of cylindrical shallow shells
Authors: Pedro Ribeiro
Venue: Finite Elements in Analysis and Design (2008)

Forced, large amplitude, periodic vibrations of open, linear elastic and isotropic, cylindrical shells are studied. A p-version finite element, which is derived following first-order shear deformation theory, is employed to define the model and an algorithm based on the shooting and Newton methods is used to solve the equations of motion. The influences that the amplitude and spatial distribution of the external excitation, the curvature to width ratio and the shell's thickness have on the dynamic response are investigated. To characterize the geometrically non-linear oscillations time plots, phase planes and Fourier spectra are employed. To characterize the stability of the solutions the Floquet multipliers are computed. Responses with even and odd harmonics to purely harmonic excitations and strong modal interactions due to the non-linearity of the system are found. The methods proposed constitute a good alternative to analyse geometrically non-linear periodic vibrations of shells because the number of approximations is reduced and the computational cost is, although significant, reasonable.
3D Gaze Tracking and Analysis for Attentive Human Computer Interaction
Authors: Jeongseok Ki, Yong-Moo Kwon, Kwanghoon Sohn
Venue: Proceedings of the 2007 Frontiers in the Convergence of Bioscience and Information Technologies (2007)

There are several researches on 2D gaze tracking techniques for the 2D screen for the Human-Computer Interaction. However, the researches for the gaze-based interaction to the stereo images or contents are not reported. The 3D display techniques are emerging now for the reality service. Moreover, the 3D interaction techniques are much more needed in the 3D contents service environments. This paper addresses gaze-based 3D interaction techniques on stereo display, such as parallax barrier or lenticular stereo display. This paper presents our researches on 3D gaze estimation and gaze-based interaction to stereo display.
Load Awareness Multi-Channel MAC Protocol Design for Ad Hoc Networks
Authors: Chih-Min Chao, Kuo-Hsiang Lu
Venue: Proceedings of the 2008 IEEE International Conference on Sensor Networks, Ubiquitous, and Trustworthy Computing (sutc 2008) (2008)

Exploiting multiple channels improves the system performance in a heavy-loaded wireless ad hoc network. Many multi-channel MAC protocols have been proposed recently. The number of channels being used is fixed for these protocols, which limits their flexibility. As a result, these protocols may suffer from either longer delay in a light-loaded network or higher collision probability in a heavy-loaded one. In this paper, we propose a Load Awareness Multichannel MAC (LAMM) protocol which dynamically adjusts the number of channels being used according to the network load. Our scheme is able to utilize multiple channels to increase throughput when the network is heavily loaded. It can also switch back to use a single channel to reduce transmission delay when the network is lightly loaded. Simulation results verify that our LAMM significantly improves the network performance.
Optimal braking and estimation of tyre friction in automotive vehicles using sliding modes
Authors: Nitin Patel, Christopher Edwards, Sarah K. Spurgeon
Venue: International Journal of Systems Science (2007)

This article proposes a sliding-mode-based scheme for optimal deceleration in an automotive braking maneuvre. The scheme is model-based and seeks to maintain the longitudinal slip value associated with the tyre road contact patch at an optimum value-the point at which the friction coefficient-slip curve reaches a maximum. The scheme assumes only wheel angular velocity is measured, and uses a sliding mode observer to reconstruct the states and a parameter relating to road conditions for use in the controller. The sliding mode controller then seeks to maintain the vehicle at this optimal slip value through an appropriate choice of sliding surface.
Integral-type operators on continuous function spaces on the real line
Authors: Francesco Altomare, Sabina Milella
Venue: Journal of Approximation Theory (2008)

In this paper we introduce some new sequences of positive linear operators, acting on a sufficiently large space of continuous functions on the real line, which generalize Gauss-Weierstrass operators. We study their approximation properties and prove an asymptotic formula that relates such operators to a second order elliptic differential operator of the form Lu@?@au^'^'+@bu^'+@cu. Shape-preserving and regularity properties are also investigated.
Statistical models for partial membership
Authors: Katherine A. Heller, Sinead Williamson, Zoubin Ghahramani
Venue: Proceedings of the 25th international conference on Machine learning (2008)

We present a principled Bayesian framework for modeling partial memberships of data points to clusters. Unlike a standard mixture model which assumes that each data point belongs to one and only one mixture component, or cluster, a partial membership model allows data points to have fractional membership in multiple clusters. Algorithms which assign data points partial memberships to clusters can be useful for tasks such as clustering genes based on microarray data (Gasch & Eisen, 2002). Our Bayesian Partial Membership Model (BPM) uses exponential family distributions to model each cluster, and a product of these distibtutions, with weighted parameters, to model each datapoint. Here the weights correspond to the degree to which the datapoint belongs to each cluster. All parameters in the BPM are continuous, so we can use Hybrid Monte Carlo to perform inference and learning. We discuss relationships between the BPM and Latent Dirichlet Allocation, Mixed Membership models, Exponential Family PCA, and fuzzy clustering. Lastly, we show some experimental results and discuss nonparametric extensions to our model.
Large-eddy simulation of buoyancy-driven natural ventilation in an enclosure with a point heat source
Authors: Ibrahim E. Abdalla, Malcolm J. Cook, Simon J. Rees, Zhiyin Yang
Venue: International Journal of Computational Fluid Dynamics (2007)

Rising buoyant plumes from a point heat source in a naturally ventilated enclosure have been investigated using large-eddy simulation (LES). The aim of the work is to assess the performance and the accuracy of LES for modelling buoyancy-driven displacement ventilation of an enclosure and to shed more light on the transitional behaviour of the plume and the coherent structures involved. The Smagorinsky sub-grid scale model is used for the unresolved small-scale turbulence. The Rayleigh number, Ra is chosen to be in the range where spatial transition from laminar to turbulent flow takes place (Ra = 1.5 × 109). The plume properties (source strength and rate of spread) as well as the ventilation properties (stratification height and temperature of stratified layer) estimated using the theory of Linden et al. are found to agree reasonably well with the LES results. The variation of the plume width with height indicates a linear variation of the entrainment coefficient rather than a constant value used by Linden et al. for a fully turbulent thermal plume. Flow visualisation revealed the nature of the large-scale coherent structures involved in the transition to turbulence in the plume. The most excited modes observed in the velocity, pressure and temperature fields spectra correspond to Strouhal number in the range 0.3 ≤ St ≤ 0.55 which is in agreement with those observed by Zhou et al. for a turbulent forced plume. Excited modes less than thisvalue (St = 0.2) were observed and may be due to low-frequency motions felt throughout the flow.
Sustaining Web Services High-Availability Using Communities
Authors: Zakaria Maamar, Quan Z. Sheng, Djamal Benslimane
Venue: Proceedings of the 2008 Third International Conference on Availability, Reliability and Security (2008)

This paper discusses how communities of Web services sustain the high availability of Web services engaged in composition scenarios. Availability is the proportion of time that a system is in a functioning condition. Web services offering the same functionality like HotelBooking are gathered into a single community regardless of who developed them, where they are located, and how they function. The current practice to achieve Web services high-availability advocates the use of replicas, which are managed according to specific replication strategies and come into play when the original Web service to back-up fails. Replacing Web services replicas with similarly functional Web services offers solutions to some of the limitations that feature these strategies, but at the same time raises other issues that are examined in this paper
Energy Estimation between Adjacent Formant Frequencies to Identify Speaker's Gender
Authors: Deepak S. Deepawale, Rajesh Bachu, Buket D. Barkana
Venue: Proceedings of the Fifth International Conference on Information Technology: New Generations (2008)

This paper describes a method developed for gender identification that combines first three formants, pitch period, and the energy between each adjacent pair of formants. The information provided by the energy, formants, and pitch estimation is combined using a classifier to identify the gender of the speaker. All the parameters are determined for a voiced part of the speech samples. We used five male and five female speech samples /one, two, three, four, five, six, seven, eight, and nine/ for our training set. All speech samples are in clear mode. The sampling frequency is 8 KHz.
Verifying LTL Properties on Hierarchical Systems: Application to Aircraft Autopilot
Authors: Mohammed Al Achhab, Ahmed Hammad, Hassan Mountassir
Venue: Proceedings of the Second International Symposium on Leveraging Applications of Formal Methods, Verification and Validation (2006)

In this paper, we are interested in verifying temporal properties of hierarchical systems when states are refined by automata. The system is modeled by hierarchical automata and temporal properties are expressed by the LTL (Linear Temporal Logic). We present a technique to cope with state explosion problem induced by the complexity of the system. The first aim is to define a refinement relation between hierarchical automata. We show that this relation preserves the LTL properties under some conditions. The advantage is that the model checking is done only on an abstraction with few states and the property is preserved in the following refinement process of systems. The second part concerns only local properties specified on the new introduced automata when the systems is refined from the abstract model. We show how to verify an usual class of patterns without using the model checking technique. The proposed approach is illustrated by a simple autopilot control.
Organizational culture and leadership in ERP implementation
Authors: Weiling Ke, Kwok Kee Wei
Venue: Decision Support Systems (2008)

This paper theorizes how leadership affects ERP implementation by fostering the desired organizational culture. We contend that ERP implementation success is positively related with organizational culture along the dimensions of learning and development, participative decision making, power sharing, support and collaboration, and tolerance for risk and conflicts. In addition, we identify the strategic and tactical actions that the top management can take to influence organizational culture and foster a culture conducive to ERP implementation. The theoretical contributions and managerial implications of this study are discussed.