ppxscal/embedding_network huggingface dataset:
Remapping-free ALE-type kinetic method for flow computations
Authors: Guoxi Ni, Song Jiang, Kun Xu
Venue: Journal of Computational Physics (2009)

Based on the integral form of the fluid dynamic equations, a finite volume kinetic scheme with arbitrary control volume and mesh velocity is developed. Different from the earlier unified moving mesh gas-kinetic method [C.Q. Jin, K. Xu, An unified moving grid gas-kinetic method in Eulerian space for viscous flow computation, J. Comput. Phys. 222 (2007) 155-175], the coupling of the fluid equations and geometrical conservation laws has been removed in order to make the scheme applicable for any quadrilateral or unstructured mesh rather than parallelogram in 2D case. Since a purely Lagrangian method is always associated with mesh entangling, in order to avoid computational collapsing in multidimensional flow simulation, the mesh velocity is constructed by considering both fluid velocity (Lagrangian methodology) and diffusive velocity (Regenerating Eulerian mesh function). Therefore, we obtain a generalized Arbitrary-Lagrangian-Eulerian (ALE) method by properly designing a mesh velocity instead of re-generating a new mesh after distortion. As a result, the remapping step to interpolate flow variables from old mesh to new mesh is avoided. The current method provides a general framework, which can be considered as a remapping-free ALE-type method. Since there is great freedom in choosing mesh velocity, in order to improve the accuracy and robustness of the method, the adaptive moving mesh method [H.Z. Tang, T. Tang, Adaptive mesh methods for one-and two-dimensional hyperbolic conservation laws, SIAM J. Numer. Anal. 41 (2003) 487-515] can be also used to construct a mesh velocity to concentrate mesh to regions with high flow gradients.
Computational Discovery of Motifs Using Hierarchical Clustering Techniques
Authors: Dianhui Wang, Nung Kion Lee
Venue: Proceedings of the 2008 Eighth IEEE International Conference on Data Mining (2008)

Discovery of motifs plays a key role in understanding gene regulation in organisms. Existing tools for motif discovery demonstrate some weaknesses in dealing with reliability and scalability. Therefore, development of advanced algorithms for resolving this problem will be useful. This paper aims to develop data mining techniques for discovering motifs. A mismatch based hierarchical clustering algorithm is proposed in this paper, where three heuristic rules for classifying clusters and a post-processing for ranking and refining the clusters are employed in the algorithm. Our algorithm is evaluated using two sets of DNA sequences with comparisons. Results demonstrate that the proposed techniques in this paper outperform MEME, AlignACE and SOMBRERO for most of the testing datasets.
An Improved Ultrasonic-Based Localization Using Reflection Method
Authors: Chen-Chien Hsu, Hsin-Chuan Chen, Chien-Yu Lai
Venue: Proceedings of the 2009 International Asia Conference on Informatics in Control, Automation and Robotics (2009)

In this paper, an ultrasonic-based localization using ultrasonic reflection method is proposed. Experiment environment includes a mobile robot and four poles forming a square around the measuring site. Ultrasonic sensors built on the poles serve as receivers and the mobile robot serves as a transmitter, and all ultrasonic sensors are integrated with their Zig-Bee modules. By the sequential ultrasonic signal transmission between the robot and the poles, the ultrasonic sensors on the poles can then measure the time-of-flight (TOF) without interference to calculate the distance between the receiver and transmitter ends. According to an established two-dimensional coordinate model, position of the robot can be obtained based on the distance measurements. Thanks to Zig-Bee modules, position information of the robot can be instantly conveyed to a remote PC for monitoring the robot and path planning. Extensive experiments conducted have shown a satisfactory accuracy of the coordinates of the mobile robot can be obtained via the proposed localization scheme.
Power saving and fault-tolerance in real-time critical embedded systems
Authors: Rodrigo M. Santos, Jorge Santos, Javier D. Orozco
Venue: Journal of Systems Architecture: the EUROMICRO Journal (2009)

In this paper, a method with the double purpose of reducing the consumption of energy and giving a deterministic guarantee on the fault tolerance of real-time embedded systems operating under the Rate Monotonic discipline is presented. A lower bound exists on the slack left free by tasks being executed at their worst-case execution time. This deterministic slack can be redistributed and used for any of the two purposes. The designer can set the trade-off point between them. In addition, more slack can be reclaimed when tasks are executed in less than their worst-case time. Fault-tolerance is achieved by using the slack to recompute the faulty task. Energy consumption is reduced by lowering the operating frequency of the processor as much as possible while meeting all time-constraints. This leads to a multifrequency method; simulations are carried out to test it versus two single frequency methods (nominal and reduced frequencies). This is done under different trade-off points and rates of faults' occurrence. The existence of an upper bound on the overhead caused by the transition time between frequencies in Rate Monotonic scheduled real-time systems is formally proved. The method can also be applied to multicore or multiprocessor systems.
An Integrated Environment for Multi-Purposing Multimedia Production
Authors: Marcus Herzog, Riccardo Peratello
Venue: Proceedings of the 1999 IEEE International Conference on Multimedia Computing and Systems - Volume 02 (1999)

Multimedia production is a resource-intensive task. Numerous media assets have to be produced, processed, and composed to form a final application. Once the application is finalized, the knowledge gained throughout the production process - and sometimes even the original media assets - are lost. Re-use of media assets in a computer-supported way does seldom take place. The Esprit project SIT-MOON aims at improving the multimedia production process by integrating media asset management systems and production tools. For this purpose the project defined interface specifications which developers can adopt to integrate their specific tools. Moreover, SIT-MOON provides additional services such as logging of the production process, managing user and project setups, and format conversion of media objects.
Attention Mechanisms in the CHREST Cognitive Architecture
Authors: Peter C. Lane, Fernand Gobet, Richard Ll. Smith
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 describe the attention mechanisms in CHREST, a computational architecture of human visual expertise. CHREST organises information acquired by direct experience from the world in the form of chunks. These chunks are searched for, and verified, by a unique set of heuristics, comprising the attention mechanism. We explain how the attention mechanism combines bottom-up and top-down heuristics from internal and external sources of information. We describe some experimental evidence demonstrating the correspondence of CHREST's perceptual mechanisms with those of human subjects. Finally, we discuss how visual attention can play an important role in actions carried out by human experts in domains such as chess.
A Performance Comparison of the Parallel Preconditioners for Iterative Methods for Large Sparse Linear Systems Arising from Partial Differential Equations on Structured Grids
Authors: Sangback Ma
Venue: IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (2008)

In this paper we compare various parallel preconditioners such as Point-SSOR (Symmetric Successive OverRelaxation), ILU(0) (Incomplete LU) in the Wavefront ordering, ILU(0) in the Multi-color ordering, Multi-Color Block SOR (Successive OverRelaxation), SPAI (SParse Approximate Inverse) and pARMS (Parallel Algebraic Recursive Multilevel Solver) for solving large sparse linear systems arising from two-dimensional PDE (Partial Differential Equation)s on structured grids. Point-SSOR is well-known, and ILU(0) is one of the most popular preconditioner, but it is inherently serial. ILU(0) in the Wavefront ordering maximizes the parallelism in the natural order, but the lengths of the wavefronts are often nonuniform. ILU(0) in the Multi-color ordering is a simple way of achieving a parallelism of the order N, where N is the order of the matrix, but its convergence rate often deteriorates as compared to that of natural ordering. We have chosen the Multi-Color Block SOR preconditioner combined with direct sparse matrix solver, since for the Laplacian matrix the SOR method is known to have a nondeteriorating rate of convergence when used with the Multi-Color ordering. By using block version we expect to minimize the interprocessor communications. SPAI computes the sparse approximate inverse directly by least squares method. Finally, ARMS is a preconditioner recursively exploiting the concept of independent sets and pARMS is the parallel version of ARMS. Experiments were conducted for the Finite Difference and Finite Element discretizations of five two-dimensional PDEs with large meshsizes up to a million on an IBM p595 machine with distributed memory. Our matrices are real positive, i.e., their real parts of the eigenvalues are positive. We have used GMRES(m) as our outer iterative method, so that the convergence of GMRES(m) for our test matrices are mathematically guaranteed. Interprocessor communications were done using MPI (Message Passing Interface) primitives. The results show that in general ILU(0) in the Multi-Color ordering and ILU(0) in the Wavefront ordering outperform the other methods but for symmetric and nearly symmetric 5-point matrices Multi-Color Block SOR gives the best performance, except for a few cases with a small number of processors.
Free-Form Surface Partition in 3-D
Authors: Danny Z. Chen, Ewa Misiołek
Venue: Proceedings of the 19th International Symposium on Algorithms and Computation (2008)

We study the problem of partitioning a spherical representation S of a free-form surface F in 3-D, which is to partition a 3-D sphere S into two hemispheres such that a representative normal vector for each hemisphere optimizes a given global objective function. This problem arises in important practical applications, particularly surface machining in manufacturing. We model the spherical surface partition problem as processing multiple off-line sequences of insertions/deletions of convex polygons alternated with certain point queries on the common intersection of the polygons. Our algorithm combines nontrivial data structures, geometric observations, and algorithmic techniques. It takes $O(\min\{m^2n \log \log m + \frac{m^3 \log^2(mn) \log^2(\log m)}{\log^3 m}, m^3\log^2n+mn\})$ time, where m is the number of polygons, of size O(n) each, in one off-line sequence (generally, m ≤ n). This is a significant improvement over the previous best-known O(m 2 n 2) time algorithm. As a by-product, our algorithm can process O(n) insertions/deletions of convex polygons (of size O(n) each) and queries on their common intersections in O(n 2 loglogn) time, improving over the "standard" O(n 2 logn) time solution for off-line maintenance of O(n 2) insertions/deletions of points and queries. Our techniques may be useful in solving other problems.
A combined neural-wavelet model for prediction of Ligvanchai watershed precipitation
Authors: Vahid Nourani, Mohammad T. Alami, Mohammad H. Aminfar
Venue: Engineering Applications of Artificial Intelligence (2009)

Doubtlessly the first step in a river management is the precipitation modeling over the related watershed. However, considering high-stochastic property of the process, many models are being still developed in order to define such a complex phenomenon in the field of hydrologic engineering. Recently artificial neural network (ANN) as a non-linear inter-extrapolator is extensively used by hydrologists for rainfall modeling as well as other fields of hydrology. In the current research, the wavelet analysis was linked to the ANN concept for prediction of Ligvanchai watershed precipitation at Tabriz, Iran. For this purpose, the main time series was decomposed to some multi-frequently time series by wavelet theory, then these time series were imposed as input data to the ANN to predict the precipitation 1 month ahead. The obtained results show the proposed model can predict both short- and long-term precipitation events because of using multi-scale time series as the ANN input layer.
The Design of OpenMP Tasks
Authors: Eduard Ayguadé, Nawal Copty, Alejandro Duran, Jay Hoeflinger, Yuan Lin, Federico Massaioli, Xavier Teruel, Priya Unnikrishnan, Guansong Zhang
Venue: IEEE Transactions on Parallel and Distributed Systems (2009)

OpenMP has been very successful in exploiting structured parallelism in applications. With increasing application complexity, there is a growing need for addressing irregular parallelism in the presence of complicated control structures. This is evident in various efforts by the industry and research communities to provide a solution to this challenging problem. One of the primary goals of OpenMP 3.0 is to define a standard dialect to express and efficiently exploit unstructured parallelism. This paper presents the design of the OpenMP tasking model by members of the OpenMP 3.0 tasking sub-committee which was formed for this purpose. The paper summarizes the efforts of the sub-committee (spanning over two years) in designing, evaluating and seamlessly integrating the tasking model into the OpenMP specification. In this paper, we present the design goals and key features of the tasking model, including a rich set of examples and an in-depth discussion of the rationale behind various design choices. We compare a prototype implementation of the tasking model with existing models, and evaluate it on a wide range of applications. The comparison shows that the OpenMP tasking model provides expressiveness, flexibility, and huge potential for performance and scalability.
Damping Control Strategies for Vibration Isolation of Disturbed Structures
Authors: Daniela Marinova
Venue: Numerical Analysis and Its Applications: 4th International Conference, NAA 2008, Lozenetz, Bulgaria, June 16-20, 2008. Revised Selected Papers (2009)

This paper investigates thin layered structures as active systems and control strategies for their vibration suppressions and shape regulating. We focus on FEM modelled thin plates. Optimal voltages for shape control are obtained using genetic optimization. An optimal selection of actuators number and locations is considered. Data fusion for reduction of input data for simplifying the controlling process is studied. Numerical simulations are presented. 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
Note: Illumination robust interest point detection
Authors: Murat Gevrekci, Bahadir K. Gunturk
Venue: Computer Vision and Image Understanding (2009)

Most interest point detection algorithms are highly sensitive to illumination variations. This paper presents a method to find interest points robustly even under large non-uniform photometric changes. The method, which we call illumination robust feature extraction transform (IRFET), determines salient interest points in an image by calculating and analyzing contrast signatures. A contrast signature shows the response of an interest point detector with respect to a set of contrast stretching functions. The IRFET is generic and can be used with most interest point detectors. In this paper, we demonstrate that the IRFET improves the repeatability rate of the Harris corner detector significantly (by around 25% on average in the experiments).
Solving the Wake-Up Scattering Problem Optimally
Authors: Luigi Palopoli, Roberto Passerone, Amy L. Murphy, Gian Pietro Picco, Alessandro Giusti
Venue: Proceedings of the 6th European Conference on Wireless Sensor Networks (2009)

In their EWSN'07 paper [1], Giusti et al. proposed a decentralized wake-up scattering algorithm for temporally spreading the intervals in which the nodes of a wireless sensor network (WSN) are active, and showed that the resulting schedules significantly improve over the commonly-used random ones, e.g., by providing greater area coverage at less energy costs. However, an open question remained about whether further improvements are possible. Here, we complete the work in [1] by providing a (centralized) optimal solution that constitutes a theoretical upper bound for wake-up scattering protocols. Simulation results shows that the decentralized algorithm proposed in [1] comes within 4% to 11% of the optimum. Moreover, we show that the modeling framework we use to derive the solution, based on integer programming techniques, allows for a particularly efficient solution. The latter result discloses important opportunities for the practical utilization of the model. The model is also general enough to encompass alternative formulations of the problem.
A multilevel finite volume method with multiscale-based grid adaptation for steady compressible flows
Authors: Siegfried Müller, Youssef Stiriba
Venue: Journal of Computational and Applied Mathematics (2009)

An implicit multilevel finite volume solver on adaptively refined quadtree meshes is presented for the solution of steady state flow problems. The nonlinear problem arising from the implicit time discretization is solved by an adaptive FAS multigrid method. Local grid adaptation is performed by means of a multiscale-based strategy. For this purpose data of the flow field are decomposed into coarse grid information and a sequence of detail coefficients that describe the difference between two refinement levels and reveal insight into the local regularity behavior of the solution. Here wavelet techniques are employed for the multiscale analysis. The key idea of the present work is to use the transfer operators of the multiscale analysis for the prolongation and restriction operator in the FAS cycle. The efficiency of the solver is investigated by means of an inviscid 2D flow over a bump.
From twin training to pair programming
Authors: Stamatia-Ann Katriou, Evangelos Tolias
Venue: Proceedings of the 2nd India software engineering conference (2009)

This is an experience report on Twin Training which arose out of a unique situation that occurred in a small research department in Thessaloniki, Greece when all the programmers left the firm. The new programmers in the department were a recent graduate and an intern unfamiliar with the required technologies to complete the unfinished European Union funded projects. This paper outlines how, without a mentor, they devised a mutually supportive training technique which enabled them to acquire both knowledge and practical skills quickly. Twin Training helped them break personal barriers and provided a supportive grounding to progress to pair programming on the projects.
Criteria for Homotopic Maps to be So Along Monotone Homotopies
Authors: Sanjeevi Krishnan
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2009)

The state spaces of machines admit the structure of time. A homotopy theory respecting this additional structure can detect machine behavior unseen by classical homotopy theory. In an attempt to bootstrap classical tools into the world of abstract spacetime, we identify criteria for classically homotopic, monotone maps of pospaces to future homotope, or homotope along homotopies monotone in both coordinates, to a common map. We show that consequently, a hypercontinuous lattice equipped with its Lawson topology is future contractible, or contractible along a future homotopy, if its underlying space has connected CW type.
Measuring the Impacts of Sampling Bias on Internet AS-Level Topology Inference
Authors: Guoqiang Zhang
Venue: Proceedings of the 2009 WRI International Conference on Communications and Mobile Computing - Volume 03 (2009)

In this paper, we carried out a systematic qualitative study of the impacts of sampling bias over Internet AS-level topology inference. Based on the relatively complete Chinese Internet AS graph derived from our large-scale measurement effort, we further quantified such impacts by showing how much peer-peer and provider-customer links were missed due to sampling bias. Moreover, we brought to light the possible incorrect inferences that can be derived about relationships between ASes if the number of sampling points is limited.
End-User Development and Meta-design: Foundations for Cultures of Participation
Authors: Gerhard Fischer
Venue: Proceedings of the 2nd International Symposium on End-User Development (2009)

The first decade of the World Wide Web predominantly enforced a clear separation between designers and consumers. New technological developments, such as the cyberinfrastructure and Web 2.0 architectures, have emerged to support a participatory Web. These developments are the foundations for a fundamental shift from a consumer culture (specialized in producing finished goods to be consumed passively) to a culture of participation (in which all people are provided with the means to participate actively in personally meaningful activities). End-user development and meta-design provide foundations for this fundamental transformation. They explore and support new approaches for the design, adoption, appropriation, adaptation, evolution, and sharing of artifacts by all participating stakeholders. They take into account that cultures of participation are not dictated by technology alone: they are the result of incremental shifts in human behavior and social organizations.
Original papers: Mobile farm equipment as a data source in an agricultural service architecture
Authors: Georg Steinberger, Matthias Rothmund, Hermann Auernhammer
Venue: Computers and Electronics in Agriculture (2009)

Information management is becoming an increasingly challenging task for farmers, especially in terms of the amount of data and the complexity of processes in precision farming. One of the most demanding functions is data acquisition. Mobile farm equipment featuring different sensors is able to collect a large amount of data while working. Automated process-data acquisition can be the basis for information-steered agricultural production. But use of these data is restricted today by hardware and software compatibility, different data formats, the lack of a concept for reusing data, and the amount of data. This paper presents a prototype implementation of an agricultural process-data service (APDS). It is part of an infrastructure for data management in information-driven plant production, developed in the Pre agro joint research project. Data are recorded in an ISOBUS environment and transferred to a server. There they are analyzed and aggregated to jobs. Data can be requested for further use via a web portal and a web service interface.