ppxscal/embedding_network huggingface dataset:
Studies of the accuracy of time integration methods for reaction-diffusion equations
Authors: David L. Ropp, John N. Shadid, Curtis C. Ober
Venue: Journal of Computational Physics (2004)

In this study we present numerical experiments of time integration methods applied to systems of reaction-diffusion equations. Our main interest is in evaluating the relative accuracy and asymptotic order of accuracy of the methods on problems which exhibit an approximate balance between the competing component time scales. Nearly balanced systems can produce a significant coupling of the physical mechanisms and introduce a slow dynamical time scale of interest. These problems provide a challenging test for this evaluation and tend to reveal subtle differences between the various methods. The methods we consider include first- and second-order semi-implicit, fully implicit, and operatorsplitting techniques. The test problems include a prototype propagating nonlinear reaction--diffusion wave, a non-equilibrium radiation--diffusion system, a Brusselator chemical dynamics system and a blow-up example. In this evaluation we demonstrate a "split personality" for the operator-splitting methods that we consider. While operatorsplitting methods often obtain very good accuracy, they can also manifest a serious degradation in accuracy due to stability problems.
Sketch Interface Based Expressive Hairstyle Modelling and Rendering
Authors: Xiaoyang Mao, Hiroki Kato, Atsumi Imamiya, Ken Anjyo
Venue: Proceedings of the Computer Graphics International (2004)

We present a new system for interactively modelingand rendering non-photorealistic hairstyles. Thesystem is featured with a user-friendly sketch interfaceallowing a user generate his/her desired hairstylesimply by drawing a few free-form strokes. Hairstylesare modeled with a new polygon based techniquecalled cluster polygon, and can be renderedexpressively to obtain hair images similar to thosefound in cell animation and cartoons.
Triangulation without translation
Authors: James Mayfield, Paul McNamee
Venue: Proceedings of the 27th annual international ACM SIGIR conference on Research and development in information retrieval (2004)

Transitive retrieval and triangulation have been proposed as ways to improve cross-language retrieval quality when translation resources have poor lexical coverage. We demonstrate that cross-language retrieval is viable for European languages with no translation resources at all; that transitive retrieval without translation does not suffer the drop-off in retrieval quality sometimes reported for transitive retrieval with translation; and that triangulation that combines multiple transitive runs with no translation can boost performance over direct translation-free retrieval.
Design Trade-Offs for Networks with Soft End-to-End Timing Constraints
Venue: Proceedings of the 10th IEEE Real-Time and Embedded Technology and Applications Symposium (2004)

As broadband capabilities on wired, wireless and mobilephone networks proliferate, real-time multimedia traffic isexpected to consume higher portions of the available bandwidth.Usage models in such networks will range fromlow-cost VoIP to high-cost, high-quality, high-resolutionvideo streams along with many intermediate data streams.Video flows, however, will have stochastic processing requirements,and they may result in very low utilization levelsif traditional real-time scheduling techniques are used.This calls for new analytical methods.In this paper, weillustrate a set of new techniques for reasoning about thelateness of such stochastic flows, and apply it to engineer awired multi-hop real-time network.We make use of 4 dominantparameters to characterize the design space: end-to-enddeadline, acceptable lateness, the number of hopsand the network workload.Given any three of these parameters,the remaning parameter can be computed.Forinstance, if a stochastic flow passes through 10 nodes, itsend-to-end deadline is 150ms, and no more than 0.1% ofthe packets can be late, what is the Maximum AllowableSystem Workload that would satisfy the lateness requirements?This maximum allowable workload can then beused to develop for the admission control policy to guaranteethat the specified timeliness requirements are met.This paper provides insights into real-time network effectsand rules of thum to properly engineer a high utilizationreal-time EDF (Earliest Deadline First) network.Simulationand experimental results validate our methods.Ourtechniques are further applicable to heterogeneous networkcases where some nodes on the flow path are bottlenecks orhave cross traffic from other flows.
On Heilbronn&#x2019;s Problem in Higher Dimension
Authors: Hanno Lefmann
Venue: Combinatorica (2003)

Heilbronn conjectured that given arbitrary n points in the 2-dimensional unit square [0, 1]2, there must be three points which form a triangle of area at most O(1/n2). This conjecture was disproved by a nonconstructive argument of Koml&#x00f3;s, Pintz and Szemer&#x00e9;di [10] who showed that for every n there is a configuration of n points in the unit square [0, 1]2 where all triangles have area at least &#x2126;(log n/n2). Considering a generalization of this problem to dimensions d&#x2265;3, Barequet [3] showed for every n the existence of n points in the d-dimensional unit cube [0, 1]d such that the minimum volume of every simplex spanned by any (d+1) of these n points is at least &#x2126;(1/nd). We improve on this lower bound by a logarithmic factor &#x0398;(log n).
&ldquo;Yeah! The Movie&rdquo;
Venue: ACM SIGGRAPH 2003 video review on Animation theater program: part 1 - Volume 145 (2003)

Ogre is our real-time rendition of Spellcraft Studio's animation "Yeah! The Movie". Using the vertex and fragment shaders, we were able to match their animation and shading, with time left over for adaptive subdivision and shadows! All so our friendly ogre could dance with his little friends before dinner. Copyright held by creator. 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
Control Flow Modeling in Statistical Simulation for Accurate and Efficient Processor Design Studies
Authors: Lieven Eeckhout, Robert H. Bell Jr., Bastiaan Stougie, Koen De Bosschere, Lizy K. John
Venue: ACM SIGARCH Computer Architecture News (2004)

Designing a new microprocessor is extremely time-consuming.One of the contributing reasons is that computerdesigners rely heavily on detailed architectural simulations,which are very time-consuming. Recent workhas focused on statistical simulation to address this issue.The basic idea of statistical simulation is to measurecharacteristics during program execution, generate asynthetic trace with those characteristics and then simulatethe synthetic trace. The statistically generated synthetictrace is orders of magnitude smaller than the original programsequence and hence results in significantly fastersimulation.This paper makes the following contributions to the statisticalsimulation methodology. First, we propose the useof a statistical flow graph to characterize the control flow ofa program execution. Second, we model delayed update ofbranch predictors while profiling program execution characteristics.Experimental results show that statistical simulationusing this improved control flow modeling attainssignificantly better accuracy than the previously proposedHLS system. We evaluate both the absolute and the relativeaccuracy of our approach for power/performance modelingof superscalar microarchitectures. The results showthat our statistical simulation framework can be used to efficientlyexplore processor design spaces.
Fast visualization of volume emissions using conservative subdivision
Authors: Mats Holmström
Venue: Mathematics and Computers in Simulation (2004)

A hierarchical volume rendering algorithm is presented. Volume emissions in optically thin media are considered A sparse hierarchical wavelet-based representation of the directional volume emission rate function is constructed top-down and then projected onto the image plane. This makes the algorithm fast, since the number of operation is proportional to the number of coefficients in the representation. Also, the sparsity minimizes the algorithm's memory requirement. The representation is constructed using conservative subdivision, making the projection onto a lower-dimensional representation trivial. The error is controlled by a threshold parameter, allowing a direct trade-off between speed and accuracy. The algorithm is especially well suited when the directional volume emission rate is computationally expensive to evaluate, since the sparse representation minimizes the number of function evaluations for rendering a volume with a specified accuracy. Since a sparse oct-tree is constructed for a specific view point the method is best suited to situations where an image is to be generated from one view point.
Geometry of homogeneous convex cones, duality mapping, and optimal self-concordant barriers
Authors: Van Anh Truong, Levent Tun&#x00e7;el
Venue: Mathematical Programming: Series A and B (2004)

We study homogeneous convex cones. We first characterize the extreme rays of such cones in the context of their primal construction (due to Vinberg) and also in the context of their dual construction (due to Rothaus). Then, using these results, we prove that every homogeneous cone is facially exposed. We provide an alternative proof of a result of G&#x00fc;ler and Tun&#x00e7; el that the Siegel rank of a symmetric cone is equal to its Carath&#x00e9;odory number. Our proof does not use the Jordan-von Neumann-Wigner characterization of the symmetric cones but it easily follows from the primal construction of the homogeneous cones and our results on the geometry of homogeneous cones in primal and dual forms. We study optimal self-concordant barriers in this context. We briefly discuss the duality mapping in the context of automorphisms of convex cones and prove, using numerical integration, that the duality mapping is not an involution on certain self-dual cones.
Towards Formal Verification of UML Diagrams Based on Graph Transformation
Authors: Yu Zhao, Yushun Fan, Xinxin Bai, Yuan Wang, Hong Cai, Wei Ding
Venue: Proceedings of the E-Commerce Technology for Dynamic E-Business, IEEE International Conference (2004)

In this paper, a meta-level and highly automated technique that could formally transform UML diagrams for verification is presented. Firstly, the meta-model hierarchical structure of UML is reviewed and the relationships among different UML diagrams are analyzed from different views. An approach for transforming and verifying UML statechart diagrams is developed based on graph transformation. This approach can be used to transform UML diagrams to Petri-nets while preserving dynamic consistency properties. Finally, the approach is validated through a case study.
Virtual Traffic Path Optimization in Connection-Oriented Networks with Stochastic Traffic
Authors: Dongfang Zheng, Xian Liu, Mrinal Mandal, Weidong Lu
Venue: Journal of Network and Systems Management (2004)

Traffic control is a critical issue in connection-oriented packet-switching networks such as asynchronus transfer mode, Mutiprotocol Label Switching, and Internet Protocol with IntServ. In this paper, we present a generalized concept, the virtual traffic path (VTP), to characterize the traffic control problems in connection-oriented networks. The VTP distribution typically addresses logical network design based on the physical network, and involves both the call level and the flow level controls. To date, various VTP optimization schemes for connection-oriented networks have been proposed. However, most reported schemes are based on the conventional flow assignment model. In this paper, we propose an extended flow assignment model focusing on the connection-oriented service with a non-linear objective function. The proposed model incorporates two concepts: VTP capacity and VTP flow, to perform the optimization. This model distributes traffic on all available VTPs evenly and takes the redundant capacities into account. In addition, we introduce a stochastic programming methodology to allocate VTPs when the injected traffic changes stochastically. Experimental results show that the proposed model and the stochastic methodology can significantly improve the performance of networks.
Dynamic Algorithm for Inferring Qualitative Models of Gene Regulatory Networks
Authors: Zheng Yun, Kwoh Chee Keong
Venue: Proceedings of the 2004 IEEE Computational Systems Bioinformatics Conference (2004)

It is still an open problem to identify functional relations with o(N·n^k) time for any domain [2], where N is the number of learning instances, n is the number of genes (or variables) in the Gene Regulatory Network (GRN) models and k is the indegree of the genes. To solve the problem, we introduce a novel algorithm, DFL (Discrete Function Learning), for reconstructing qualitative models of GRNs from gene expression data in this paper. We analyze its complexity of O(k · N · n^2) on the average and its data requirements. We also perform experiments on both synthetic and Cho et al. [7] yeast cell cycle gene expression data to validate the efficiency and prediction performance of the DFL algorithm. The experiments of synthetic Boolean networks show that the DFL algorithm is more efficient than current algorithms without loss of prediction performances. The results of yeast cell cycle gene expression data show that the DFL algorithm can identify biologically significant models with reasonable accuracy, sensitivity and high precision with respect to the literature evidences.We further introduce a method called ¿ function to deal with noises in data sets. The experimental results show that the ¿ function method is a good supplement to the DFL algorithm.
Non-Preemptive Preferences in Multi-Agent Task Processing
Authors: S. Misbah Deen
Venue: Proceedings of the Database and Expert Systems Applications, 15th International Workshop (2004)

Preferences are assigned on consumable resources during task execution. We have presented here a scheme for handling such preferences in non-preemptive allocations for two types of task in a multi-agent environment with the object of finding a solution that preserves the highest number of preferences. The task types are: distributed query processing (such as a travel plan) and object creation (such as cooperative design). In both cases, convergence can be guaranteed because of non-preemption, but the quickest path for the best solution is harder to identify.
Quadrangulations and 4-color-critical graphs
Authors: Carsten Thomassen
Venue: Journal of Combinatorial Theory Series B (2004)

Erdös asked if the removal of few edges in a large 4-color-critical graph always leaves a 3-chromatic graph. Erdös and Hajnal asked if a graph is 3-colorable if all its induced subgraphs can be made bipartite by the omission of few edges (relative to the number of vertices). We answer both problems, which are stated in Bollobas' monograph Extremal Graph Theory from 1978, in the negative.
Towards Predicting Real-Time Properties of a Component Assembly
Authors: Egor Bondarev, Peter de With, Michel Chaudron
Venue: Proceedings of the 30th EUROMICRO Conference (2004)

This paper addresses the prediction of timing properties of a component-based application already during the composition phase. At this stage, it is of vital importance to guarantee that the timing requirements (e.g. end-to-end deadlines) of a real-time application that is executed on a target system will be satisfied. This is obtained by predicting the real-time behaviour of a component-based application. In this paper, we extend an already existing scenario-based approach [Prediction of Run-time Consumption in Multi-task Component-Based Systems]with the possibility to model the behaviour of an application and the behavior of the underlying components. As a result, an application developer can reason accurately about the dynamic resource consumption and real-time properties of a component assembly. The modeling involves the specification of synchronization constraints for tasks and the simulation of application behaviour. A concluding case-study of video encoder development reveals that the approach is not only feasible but also addresses yet unsolved problems of task parallel execution and synchronization.
Segmental Duplications Containing Tandem Repeated Genes Encoding Putative Deubiquitinating Enzymes
Authors: Hong Liu, Li Li, Asher Zilberstein, Chang S. Hahn
Venue: Proceedings of the 2004 IEEE Computational Systems Bioinformatics Conference (2004)

Both inter- and intra-chromosomal segmental duplications are known occurred in human genome during evolution. Few cases of such segments involving functional genes have been reported. While searching for the human orthologs of murine hematopoietic deubiquitinating enzymes (DUBs), we identified four clusters of DUB-like genes on chromosome 4p15 and chromosome 8p22-23 that are over 90% identical to each other at the DNA level. These genes are expressed in a cell type- and activation-specific manner, with different clusters possessing potentially distinct expression profiles. Examining the surrounding sequences of these gene duplication events, we have identified previously unreported conserved sequence elements that are as large as 35 to 74 kb encircling the gene clusters. Traces of these elements are also found on chromosome 12p13 and chromosome 11q13. The coding and immediate upstream sequences for DUB-like genes as well as the surrounding conserved elements, are present in the chimpanzee trace database, but not in rodent genome. We hypothesize that the segments containing these DUB clusters and surrounding elements arose relatively recently in evolution through inter- and intra-chromosomal duplicative transpositions, following the divergence of primates and rodents. Genome wide systematical search of the segmental duplication containing duplicated gene cluster has been performed.
Computing curvature-adaptive surface triangulations of three-dimensional image data
Authors: Nils Krahnstoever, Cristian Lorenz
Venue: The Visual Computer: International Journal of Computer Graphics (2004)

An adaptive surface triangulation algorithm for binary 3D image data is presented. The proposed method is robust and efficient and yields a high-quality surface-mesh description. The main idea of the algorithm is based on selecting a subset of the object voxel surface elements as the vertices of the triangulation and to obtain a discrete approximation of the Voronoi graph on the object surface to generate its dual, the surface Delaunay triangulation. The presented approach incorporates local object shape into the early stages of the algorithm, yielding an elegant method for obtaining shape-adaptive triangular meshes. One of the main advantages of the presented method over previous approaches is that no intermediate surface representation other than the trivial voxel representation provided by the input data is necessary. The method is presented in detail and tested on synthetic as well as real images.
Electrical characterization of SrTiO3 thin films deposited on Si(001) substrate by liquid injection MOCVD
Authors: J. Legrand, S. Lhostis, Y. Chang, L. Militaru, C. Lamard, A. Sibai, L. Auvray, M. Audier, J.-P. Sénateur, C. Dubourdieu, F. Ducroquet
Venue: Microelectronic Engineering (2004)

The electrical properties of SrTiO3 thin films grown on Si substrates by liquid injection MOCVD have been investigated as a function of films thickness (from 4 to 200 nm). Using an heterometallic precursor and optimised low pressure conditions, highly textured SrTiO3 films were obtained in a 30-150 nm thickness range. A continuous increase of the SrTiO3 dielectric permittivity with increasing films thickness is deduced, and an interface state density minimum value, lower than 1 × 1011 cm-2 eV-1 is observed for 30 nm films. The lowest gate current is obtained for 30-50 nm films: in those samples, the conduction is identified as a Schottky emission type mechanism. For thinner films, the gate current increases when the thickness decreases as classically observed for amorphous oxides. For thicker samples, the leakage current is enhanced by the polycrystalline microstructure of the SrTiO3 films.
Error Rates in Generalized Shadowed Fading Channels
Authors: P. M. Shankar
Venue: Wireless Personal Communications: An International Journal (2004)

Most of the existing models to describe the shadowed fading channels use either the Suzuki or Nakagami-lognormal probability density function (pdf), both based on lognormal shadowing. However, these two density functions do not lead to closed form solutions for the received signal power, making the computations of error rates and outages very cumbersome. A generalized or compound fading model which takes into account both fading and shadowing in wireless systems, is presented here. Starting with the Nakagami model for fading, shadowing is incorporated using a gamma distribution for the average power in the Nakagami fading model. This compound pdf developed here based on a gamma-gamma distribution is analytically simpler than the two pdfs based on lognormal shadowing and is general enough to incorporate most of the fading and shadowing observed in wireless channels. The performance of coherent BPSK is evaluated using this compound fading model.
Differential Index Update in Cooperative Search Engine
Authors: Nobuyoshi Sato, Minoru Uehara
Venue: Proceedings of the Database and Expert Systems Applications, 15th International Workshop (2004)

Cooperative Search Engine (CSE) is a distributed search engine, which can update index in very short time for the purpose of fresh information retrieval. Although CSEýs retrieval response time was longer than general centralized search engines, we developed some techniques to accelerate CSEýs retrieval response time. As a routine work, CSE finds new documents and new words, and updates the index. In this daily update process, removed documents and words were not considered due to update processing speed. So we developed a new daily update process, differential update. Differential update considers added, modified and removed documents and words. In this paper, we will describe behavior, evaluation of differential update.
Temporal Range Exploration of Large Scale Multidimensional Time Series Data
Authors: Joseph JaJa, Jusub Kim, Qin Wang
Venue: Proceedings of the 16th International Conference on Scientific and Statistical Database Management (2004)

We consider the problem of querying large scale multidimensionaltime series data to discover events of interest,test and validate hypotheses, or to associate temporalpatterns with specific events.Large amounts of multidimensionaltime series data are currently available, andthis type of data is growing at a fast rate due to the currenttrends in collecting time series of business, scientific, demographic,and simulation data.The ability to exploresuch collections interactively, even at a coarse level, willbe critical in discovering the information and knowledgeembedded in such collections.We develop indexing techniquesand search algorithms to efficiently handle temporalrange value querying of multidimensional time seriesdata.Our indexing uses linear space data structuresthat enable the handling of queries very efficiently, invokingin the worst case a logarithmic number of queriesto single time slices.We also show that our algorithmis ideally suited for parallel implementation on clustersof processors achieving a linear speedup in the number ofavailable processors.A particularly simple data structurewith provably good bounds is also presented for the casewhen the number of multidimensional objects is relativelysmall.These techniques improve significantly over previoustechniques for either the serial or the parallel case,and are evaluated by extensive experimental results thatconfirm their superior performance.