ppxscal/embedding_network huggingface dataset:
A Linear Bound on the Complexity of the Delaunay Triangulation of Points on Polyhedral Surfaces
Authors: Dominique Attali, Jean-Daniel Boissonnat
Venue: Discrete Computational Geometry (2004)

Delaunay triangulations and Voronoi diagrams have found numerous applications in surface modeling, surface mesh generation, deformable surface modeling and surface reconstruction. Many algorithms in these applications begin by constructing the three-dimensional Delaunay triangulation of a finite set of points scattered over a surface. Their running-time therefore depends on the complexity of the Delaunay triangulation of such point sets.Although the complexity of the Delaunay triangulation of points in R3 may be quadratic in the worst case, we show in this paper that it is only linear when the points are distributed on a fixed set of well-sampled facets of R3 (e.g. the planar polygons in a polyhedron). Our bound is deterministic and the constants are explicitly given.
Finite element method for epitaxial growth with attachment-detachment kinetics
Authors: Eberhard Bänsch, Frank Haußer, Omar Lakkis, Bo Li, Axel Voigt
Venue: Journal of Computational Physics (2004)

An adaptive finite element method is developed for a class of free or moving boundary problems modeling island dynamics in epitaxial growth. Such problems consist of an adatom (adsorbed atom) diffusion equation on terraces of different height; boundary conditions on terrace boundaries including the kinetic asymmetry in the adatom attachment and detachment; and the normal velocity law for the motion of such boundaries determined by a two-sided flux, together with the one-dimensional "surface" diffusion. The problem is solved using two independent meshes: a two-dimensional mesh for the adatom diffusion and a one-dimensional mesh for the boundary evolution. The diffusion equation is discretized by the first-order implicit scheme in time and the linear finite element method in space. A technique of extension is used to avoid the complexity in the spatial discretization near boundaries. All the elements are marked, and the marking is updated in each time step, to trace the terrace height. The evolution of the terrace boundaries includes both the mean curvature flow and the surface diffusion. Its governing equation is solved by a semi-implicit front-tracking method using parametric finite elements. Simple adaptive techniques are employed in solving the adatom diffusion as well as the boundary motion problem. Numerical tests on pure geometrical motion, mass balance, and the stability of a growing circular island demonstrate that the method is stable, efficient, and accurate enough to simulate the growing of epitaxial islands over a sufficiently long time period.
Evolutionary testing of classes
Authors: Paolo Tonella
Venue: ACM SIGSOFT Software Engineering Notes (2004)

Object oriented programming promotes reuse of classes in multiple contexts. Thus, a class is designed and implemented with several usage scenarios in mind, some of which possibly open and generic. Correspondingly, the unit testing of classes cannot make too strict assumptions on the actual method invocation sequences, since these vary from application to application.In this paper, a genetic algorithm is exploited to automatically produce test cases for the unit testing of classes in a generic usage scenario. Test cases are described by chromosomes, which include information on which objects to create, which methods to invoke and which values to use as inputs. The proposed algorithm mutates them with the aim of maximizing a given coverage measure. The implementation of the algorithm and its application to classes from the Java standard library are described.
Baby changing station
Venue: ACM SIGGRAPH 2003 video review on Animation theater program: part 1 - Volume 145 (2003)

Seeking a moment's peace in a mall bathroom, an exasperated father places his screaming, dirty-diapered child on a baby changing station and tries to regain his composure. The baby's screams seem to grow louder and show no sign of stopping. And then, silence. He's afraid to look, but when he does, transformation of his attitude is not the only change that occurs in this tale of diapers and drool, despair and delight. Copyright held by creator.
Quasioptimality of some spectral mixed methods
Authors: Jayadeep Gopalakrishnan, Leszek F. Demkowicz
Venue: Journal of Computational and Applied Mathematics (2004)

In this paper, we construct a sequence of projectors into certain polynomial spaces satisfying a commuting diagram property with norm bounds independent of the polynomial degree. Using the projectors, we obtain quasioptimality of some spectral mixed methods, including the Raviart-Thomas method and mixed formulations of Maxwell equations. We also prove some discrete Friedrichs type inequalities involving curl.
Developing Squeak-Based Curricula through a Collaborative "TIDE" Course at Kyoto University and UCLA
Authors: Kentaro Yoshimasa, Yoshiki Ohshima, Kim Rose
Venue: Proceedings of the Second International Conference on Creating, Connecting and Collaborating through Computing (2004)

We have been using SqueakToys in the ALAN-Kproject to construct new type of education environment.While SqueakToys has great potential, teachers at Kyotoschools have shown hesitation to use it in regular classesmainly because there has not been any establishedcourse material yet.An approach we took in order to overcome thisproblem was to work with the students of the TIDEcourse at Kyoto University and UCLA. The uniquecharacteristics of the TIDE course were that the lecturewas focused on the childhood education with computers.Also, the students of this course have diverse backgroundnot only the grade or faculty but also the nationality.This was preferable set of students not only because thecourse treated the education issue, but also the studentsmanaged to provide different viewpoints.In the first part of the course, students participatedin the joint course taught by Alan Kay and YahikoKambayashi about computing and education. Based onthe insight from the lectures, the students tried to developSqueak-based class materials that attempted toencourage the creativity of children. Finally, studentsheld workshops with 5th and 6th grade children toevaluate their materials.In this paper, we report the experience and resultsfrom this course.
Akryls
Venue: ACM SIGGRAPH 2003 video review on Animation theater program: part 2 - Volume 146 (2003)

Let us enter the tiny universe of the infinitesimal in the infinitely big, and beyond. Copyright held by creator.
Dynamic plan migration for continuous queries over data streams
Authors: Yali Zhu, Elke A. Rundensteiner, George T. Heineman
Venue: Proceedings of the 2004 ACM SIGMOD international conference on Management of data (2004)

Dynamic plan migration is concerned with the on-the-fly transition from one continuous query plan to a semantically equivalent yet more efficient plan. Migration is important for stream monitoring systems where long-running queries may have to withstand fluctuations in stream workloads and data characteristics. Existing migration methods generally adopt a pause-drain-resume strategy that pauses the processing of new data, purges all old data in the existing plan, until finally the new plan can be plugged into the system. However, these existing strategies do not address the problem of migrating query plans that contain stateful operators, such as joins. We now develop solutions for online plan migration for continuous stateful plans. In particular, in this paper, we propose two alternative strategies, called the moving state strategy and the parallel track strategy, one exploiting reusability and the second employs parallelism to seamlessly migrate between continuous join plans without affecting the results of the query. We develop cost models for both migration strategies to analytically compare them. We embed these migration strategies into the CAPE [7], a prototype system of a stream query engine, and conduct a comparative experimental study to evaluate these two strategies for window-based join plans. Our experimental results illustrate that the two strategies can vary significantly in terms of output rates and intermediate storage spaces given distinct system configurations and stream workloads.
TLSF: A New Dynamic Memory Allocator for Real-Time Systems
Authors: M. Masmano, I. Ripoll, A. Crespo, J. Real
Venue: Proceedings of the 16th Euromicro Conference on Real-Time Systems (2004)

Dynamic storage allocation (DSA) algorithms playan important role in the modern software engineeringparadigms and techniques (such as object oriented programming).Using DSA increases the flexibility and functionalitiesof applications. There exists a large number ofreferences to this particular issue in the literature. However,the use of DSA has been considered a source of indeterminismin the real-time domain, due to the unconstrained responsetime of DSA algorithms and the fragmentation problem.Nowadays, new real-time applications require more flexibility:the ability to adjust system configuration in responseto workload changes and application reconfiguration. Thisaspect adds new value to the definition and implementationof dynamic storage allocation algorithms.Considering these reasons, new DSA algorithms with abounded and acceptable timing behaviour must be developedto be used by Real-Time Operating Systems (RTOSs).In this paper a new DSA algorithm called Two-Level SegregatedFit memory allocator (TLSF), developed specificallyto be used by RTOS, is introduced. The TLSF algorithm providesexplicit allocation and deallocation of memory blockswith a temporal cost ¿(1).
Software-based computing security and fault tolerance
Authors: Goutam Kumar Saha
Venue: Ubiquity (2004)

This article delineates a software approach to establish computing security and fault tolerance in various computing systems. This low-cost approach is useful to tolerate malicious code modifications and transient faults without additional costs for hardware and extra software versions.
Impact of far-field interactions on performance of multipole-based preconditioners for sparse linear systems
Authors: Ananth Y. Grama, Vivek Sarin
Venue: Proceedings of the 18th annual international conference on Supercomputing (2004)

Dense operators for preconditioning sparse linear systems have traditionally been considered infeasible due to their excessive computational and memory requirements. With the emergence of techniques such as block low-rank approximations and hierarchical multipole approximations, the cost of computing and storing these preconditioners has reduced dramatically. In our prior work [15], we have demonstrated the use of multipole-based techniques as effective parallel preconditioners for sparse linear systems. At one extreme, multipole-based preconditioners behave as dense (bounded interaction) matrices (multipole degree 0), while at the other extreme, they are represented entirely as series expansions. In this paper, we show that: (i) merely truncating the kernel of the integral operator generating the preconditioner leads to poor convergence properties; (ii) far-field interactions, in the form of multipoles, are critical for rapid convergence; (iii) the importance and required accuracy of far-field interactions varies with the complexity of the problem; and (iv) the preconditioner resulting from a judicious mix of near and far-field interactions yields excellent convergence and parallelization properties. Our experimental results are illustrated on the Poisson problem and the generalized Stokes problem arising in incompressible fluid flow simulations.
Lighting Design in Low-Cost Immersive Systems
Authors: Juan A. Magallon, Emilio J. Sobreviela, Francisco J. Seron, Diego Gutierrez
Venue: Proceedings of the Computer Graphics International (2004)

GIGA (the Advanced Computer Graphics Group fromthe University of Zaragoza) has developed two packages,code-named ALEPH and SICARA3D. Those systems are capableof both calculating light distribution in complex environments,based on a rigorous simulation of the physicalphenomena involved, and visualizing the results in a photorealisticway, including models of the HVS (Human VisualSystem) implemented in a third package code-namedS·E·K·E·R. Our systems support, as a remarkable differencewith respect to all other known systems like RADIANCE([8]), a spectral management of lighting magnitudes,instead of working with simple RGB. We have also added tothis framework the power of low-cost CAVE immersive systems.With this combination, we include stereoscopy and acollaborative environment to the reliability of the numericalresults and the realistic aspect of the imagery.
Constructing a text corpus for inexact duplicate detection
Authors: Jack G. Conrad, Cindy P. Schriber
Venue: Proceedings of the 27th annual international ACM SIGIR conference on Research and development in information retrieval (2004)

As online document collections continue to expand, both on the Web and in proprietary environments, the need for duplicate detection becomes more critical. The goal of this work is to facilitate (a) investigations into the phenomenon of near duplicates and (b) algorithmic approaches to minimizing its negative effect on search results. Harnessing the expertise of both client-users and professional searchers, we establish principled methods to generate a test collection for identifying and handling inexact duplicate documents.
FEM-simulation of laminar flame propagation: I: two-dimensional flames
Authors: B. Michaelis, B. Rogg
Venue: Journal of Computational Physics (2004)

In this paper, we present a numerical model for two-dimensional low-Mach-number flows of reactive ideal-gas mixtures based on the fundamental conservation equations in primitive variables. Chemical reaction is described by a detailed mechanism of elementary reactions, and detailed models for molecular transport and thermodynamics are taken into account. The equations are discretized by a finite-element method on unstructured grids using the well known Taylor-Hood element. A streamline-diffusion upwinding technique is used to avoid instabilities in convection-dominated regions of the flowfield. A fully operative local adaptive mesh-refinement procedure is used. As numerical examples we consider steadily, propagating laminar flames in flat channels, which appear in a variety of shapes depending on the boundary conditions.
Dictionary matching and indexing with errors and don't cares
Authors: Richard Cole, Lee-Ad Gottlieb, Moshe Lewenstein
Venue: Proceedings of the thirty-sixth annual ACM symposium on Theory of computing (2004)

This paper considers various flavors of the following online problem: preprocess a text or collection of strings, so that given a query string p, all matches of p with the text can be reported quickly. In this paper we consider matches in which a bounded number of mismatches are allowed, or in which a bounded number of "don't care" characters are allowed. The specific problems we look at are: indexing, in which there is a single text t, and we seek locations where p matches a substring of t; dictionary queries, in which a collection of strings is given upfront, and we seek those strings which match p in their entirety; and dictionary matching, in which a collection of strings is given upfront, and we seek those substrings of a (long) p which match an original string in its entirety. These are all instances of an all-to-all matching problem, for which we provide a single solution.The performance bounds all have a similar character. For example, for the indexing problem with n=|t| and m=|p|, the query time for k substitutions is O(m + (c1 log n)k⁄k! + # matches), with a data structure of size O(n (c2 log n)k⁄k!) and a preprocessing time of O(n (c2 log n)k⁄k!), where c1,c2 > 1 are constants. The deterministic preprocessing assumes a weakly nonuniform RAM model; this assumption is not needed if randomization is used in the preprocessing.
Analysis of privacy preserving random perturbation techniques: further explorations
Authors: Haimonti Dutta, Hillol Kargupta, Souptik Datta, Krishnamoorthy Sivakumar
Venue: Proceedings of the 2003 ACM workshop on Privacy in the electronic society (2003)

Privacy is becoming an increasingly important issue in many data mining applications, particularly in the security and defense area. This has triggered the development of many privacy-preserving data mining techniques. A large fraction of them uses randomized data distortion techniques to mask the data for preserving the privacy. They attempt to hide the sensitive data by randomly modifying the data values using additive noise. This paper questions the utility of such randomized data distortion technique for preserving privacy in many cases and urges caution. It notes that random objects (particularly random matrices) have "predictable" structures in the spectral domain and then offers a random matrix-based spectral filtering technique to retrieve original data from the data-set distorted by adding random values. It extends our earlier work questioning the efficacy of random perturbation techniques using additive noise for privacy-preserving data mining in continuous valued domain and presents new results in the discrete domain. It shows that the growing collection of random perturbation-based "privacy-preserving" data mining techniques may need a careful scrutiny in order to prevent privacy breaches through linear transformations. The paper also presents extensive experimental results in order to support this claim.
Practices of Information Education with Squeak toward the Secure Improvement of 'Academic Ability'
Authors: Takeshi Fujioka, Hiroki Karuno, Yahiko Kambayashi
Venue: Proceedings of the Second International Conference on Creating, Connecting and Collaborating through Computing (2004)

This paper describes a curriculum of informationeducation using Squeak at Horikawa High School,which is specified as "Super Science High School(SSH)" where teachers try innovative teaching methodsto stimulate students' interests in science. Thiscurriculum aims to achieve the objectives of a subject"Information Study" specified by the Ministry ofEducation, Culture, Sports, Science and Technology.We consider that Squeak can provide powerfulenvironments where students can think and try,confirming the results visually, and the environmentsare ideal for them to learn how to design and evaluateGraphical User Interface. In this paper, we introducethe first effort to create a curriculum for a subject"Basic Inquiry" in SSH.
Efficient Peer-to-Peer Overlay Construction
Authors: Lionel M. Ni, Yunhao Liu
Venue: Proceedings of the E-Commerce Technology for Dynamic E-Business, IEEE International Conference (2004)

In unstructured peer-to-peer (P2P) systems, the mechanism of a peer randomly joining and leaving a P2P network causes topology mismatch between the P2P logical overlay network and the physical underlying network, causing a large volume of redundant traffic in the Internet. In order to alleviate the mismatching problem, we introduce several distributed algorithms to optimize the overlay, while retaining the search scope. Our simulation study shows that this approach can effectively solve the mismatch problem and significantly reduce P2P traffic and response time.
Bounds on the Chv&#x00e1;tal Rank of Polytopes in the 0/1-Cube
Authors: Friedrich Eisenbrand, S. Schulz
Venue: Combinatorica (2003)

Gomory&#x2019;s and Chv&#x00e1;tal&#x2019;s cutting-plane procedure proves recursively the validity of linear inequalities for the integer hull of a given polyhedron. The Chv&#x00e1;tal rank of the polyhedron is the number of rounds needed to obtain all valid inequalities. It is well known that the Chv&#x00e1;tal rank can be arbitrarily large, even if the polyhedron is bounded, if it is 2-dimensional, and if its integer hull is a 0/1-polytope.We show that the Chv&#x00e1;tal rank of polyhedra featured in common relaxations of many combinatorial optimization problems is rather small; in fact, we prove that the rank of every polytope contained in the n-dimensional 0/1-cube is at most n2(1+log n). Moreover, we also demonstrate that the rank of any polytope in the 0/1-cube whose integer hull is defined by inequalities with constant coefficients is O(n).Finally, we provide a family of polytopes contained in the 0/1-cube whose Chv&#x00e1;tal rank is at least (1 + &#x03b5;) n, for some &#x03b5; > 0.
Stable Multiway Circuit Partitioning for ECO
Authors: Yongseok Cheon, Seokjin Lee, Martin D. F. Wong
Venue: Proceedings of the 2003 IEEE/ACM international conference on Computer-aided design (2003)

We propose a new stable multiway partitioning algorithm,where stability is defined as an additional quality of a partitioningsolution. The stability of a partitioning algorithm isan important criterion for a partitioning based placement toachieve timing closure through the repetition of the placementprocedure [Invited talk: Important Placement Considerations for Modern VLSI Chips]. Given a previous partitioning result P*on an original netlist hypergraph H* and a partially modifiednetlist hypergraph H, a new cost function with similarityfactor is defined to produce a new partition P on Hwhich is similar to the original partition P*. The proposedalgorithm is the first approach that quantifies the degree ofsimilarity of a current partition to the original partition usingsimilarity cost. Our goal is to build a new partition ina relatively short run time, whose cut quality is not muchdegraded from that of the original partition P* while it preservesas much of the previous groupings in P* as possible.The proposed partitioner is especially beneficial to engineeringchange order (ECO) applications, where partial modificationsof a netlist are handled by the incremental methodologyin a design iteration cycle. Our approach helps ECOplacers maximize the incremental capability since the portionsto be re-placed are minimized. Experimental resultsshow that the proposed algorithm achieves a high qualitypartition comparable to a state-of-the-art multilevel partitionerhMetis [Multilevel k-way hypergraph partitioning], while many portions of the groupings in the previous partition are preserved in the current partition.The tradeoff between similarity and cut quality with respectto a varying similarity coefficient is also shown.
Exploring human centred approaches in market research and product development: three case studies
Authors: Marc Steen, Nicole de Koning, Arlette Pikaart
Venue: Proceedings of the conference on Dutch directions in HCI (2004)

How can human centred approaches in market research and product development improve the process and results of innovation? Based on case studies two recommendations are formulated: 1) use a comprehensive view on man for studying people's behaviour, needs and wishes while they use products or services; and 2) employ an open dialogue and cooperation between the project's client, people in R&D, and end-users or customers, including a willingness and ability to change the product based on the findings.
Analyses of an Agile Methodology Implementation
Authors: Sylvia Ilieva, Penko Ivanov, Eliza Stefanova
Venue: Proceedings of the 30th EUROMICRO Conference (2004)

In the last few years Agile methodologies appeared as a reaction to traditional ways of developing software and acknowledge the need for an alternative to documentation driven, heavyweight software development processes. This paper shortly presents an agile approach for software development of e-business applications. The approach, named eXPERT, is applicable to small teams developing projects characterised by often changing requirements, tight schedules, and high quality demands. The present article describes a case study about eXPERT approach implementation at software developing company. Experiment results based on preliminary defined series of metrics are presented and analyzed.