ppxscal/embedding_network huggingface dataset:
A New Line Clipping Algorithm with Hardware Acceleration
Authors: Vaclav Skala
Venue: Proceedings of the Computer Graphics International (2004)

Algorithms for line clipping against convex polygonhave been studied for a long time and many researchpapers have been published so far. In spite of the latestgraphical hardware development and significantincrease of performance the clipping is still abottleneck of the graphical pipeline. This paperpresents a new robust and fast algorithm for lineclipping by a convex polygon. The algorithm usesa small pre-processing in order to obtain significantspeed up. The proposed algorithm is especiallyconvenient for applications where points or lines arerepresented in homogeneous coordinates. Thealgorithm does not use division in floating pointrepresentation as the resulting points are inhomogeneous coordinates. The algorithms will benefitif vector-vector hardware supported operations can beused.
Integrating GML Resources and Other Web Resources
Authors: J. E. Corcoles, P. Gonzalez
Venue: Proceedings of the Database and Expert Systems Applications, 15th International Workshop (2004)

In tackling the Semantic Web, a rich domain that requires special attention is the Semantic Geospatial Web. In this paper we make a contribution to the Semantic Geospatial Web by defining an approach based on an ontology for integrating non-spatial resources such as html, pdf, pictures (gif, jpg), etc., with GML documents. It is based on a Catalog which stores descriptions about both non-spatial resources and GML documents. These descriptions have to satisfy, fully or partially, an ontology to be stored in the Catalog. Thus, this approach allows the execution of queries that include spatial and non-spatial operators over both kinds of resources.
A poly-algorithmic approach to simplifying elementary functions
Authors: James C. Beaumont, Russell J. Bradford, James H. Davenport, Nalina Phisanbut
Venue: Proceedings of the 2004 international symposium on Symbolic and algebraic computation (2004)

Simplification has been long recognised to be a fundamental problem within computer algebra [17]. However, even for the class of elementary functions, it has not been resolved in a satisfactory way.Algorithms were presented in [4, 2] to solve this problem, and it was seen that both methods had their own strengths and weaknesses. Also, not all functions could be handled by either of the methods alone. The current paper continues this line of development by combining the two methods, and reporting on progress made with the various sub-algorithms involved.
AMPS: a flexible, scalable proxy testbed for implementing streaming services
Authors: Xiaolan Zhang, Michael K. Bradshaw, Yang Guo, Bing Wang, Jim Kurose, Prashant Shenoy, Don Towsley
Venue: Proceedings of the 14th international workshop on Network and operating systems support for digital audio and video (2004)

We present the design, implementation, and performance evaluation of AMPS --- a flexible, scalable proxy testbed that supports a wide and extensible set of next-generation proxy streaming services. AMPS employs a modular architecture and is built on top of a commodity Linux system. We study the performance of AMPS proxy using a server-proxy-client configuration in a switched-Gigabit LAN environment. We identify the CPU to be the system bottleneck. Through profiling study, we further identify the kernel network protocol processing and the Network Reception Module inside the proxy to be the most CPU-intensive components. We also quantify the maximum achievable throughput for two of the principal components of the proxy - the control plane and data plane, and characterize the end-to-end performance along the server-to-proxy-to-client path. We discuss lessons learned and the various optimizations made in the course of our study to improve system performance.
Early analysis tools for system-on-a-chip design
Authors: J. A. Darringer, R. A. Bergamaschi, S. Bhattacharya, D. Brand, A. Herkersdorf, J. K. Morrell, I. Nair, P. Sagmeister, Y. Shin
Venue: IBM Journal of Research and Development (2002)

The paper describes the need for early analysis tools to enable developers of today's system-on-a-chip (SoC) designs to take advantage of pre-designed components, such as those found in the IBM Blue LogicÂ® Library, and rapidly explore high-level design alternatives to meet their system requirements. We report on a new approach for developing high-level performance models for these SoC designs and outline how this performance analysis capability can be integrated into an overall environment for efficient SoC design.
Reliable Krylov-based algorithms for matrix null space and rank
Authors: Wayne Eberly
Venue: Proceedings of the 2004 international symposium on Symbolic and algebraic computation (2004)

Krylov-based algorithms have recently been used, in combination with other methods, to solve systems of linear equations and to perform related matrix computations over finite fields. For example, large and sparse systems of linear equations ;2; are formed during the use of the number field sieve for integer factorization, and elements of the null space of these systems are sampled.Two rather different kinds of block algorithms have recently been considered. Block Wiedemann algorithms have now been presented and fully analyzed. Block Lanczos algorithms were proposed earlier but are not yet as well understood. In particular, proofs of reliability of block Lanczos algorithms are not yet available. Nevertheless, an examination of the computational number theory literature suggests that block Lanczos algorithms continue to be preferred.This report presents a block Lanczos algorithm that is somewhat simpler than block algorithms that are presently in use and provably reliable for computations over large fields. To my knowledge, this is the first block Lanczos algorithm for which a proof of reliability is available.A different Krylov-based approach is considered for computations over small fields: It is shown that if Wiedemann's sparse matrix preconditioner is applied to an arbitrary matrix then the number of nontrivial invariant factors of the result is, with high probability, quite small. A Krylov-based algorithm to compute a partial Frobenius decomposition can then be used to sample from the null space of the original matrix or to compute its rank. This yields a randomized (Monte Carlo) black box algorithm for matrix rank that is asymptotically faster, in the small field case, than any other that is presently known.
Buffering databse operations for enhanced instruction cache performance
Authors: Jingren Zhou, Kenneth A. Ross
Venue: Proceedings of the 2004 ACM SIGMOD international conference on Management of data (2004)

As more and more query processing work can be done in main memory access is becoming a significant cost component of database operations. Recent database research has shown that most of the memory stalls are due to second-level cache data misses and first-level instruction cache misses. While a lot of research has focused on reducing the data cache misses, relatively little research has been done on improving the instruction cache performance of database systems.We first answer the question "Why does a database system incur so many instruction cache misses?" We demonstrate that current demand-pull pipelined query execution engines suffer from significant instruction cache thrashing between different operators. We propose techniques to buffer database operations during query execution to avoid instruction cache thrashing. We implement a new light-weight "buffer" operator and study various factors which may affect the cache performance. We also introduce a plan refinement algorithm that considers the query plan and decides whether it is beneficial to add additional "buffer" operators and where to put them. The benefit is mainly from better instruction locality and better hardware branch prediction. Our techniques can be easily integrated into current database systems without significant changes. Our experiments in a memory-resident PostgreSQL database system show that buffering techniques can reduce the number of instruction cache misses by up to 80% and improve query performance by up to 15%.
Extraction of Java program fingerprints for software authorship identification
Authors: Haibiao Ding, Mansur H. Samadzadeh
Venue: Journal of Systems and Software (2004)

Computer programs belong to the authors who design, write, and test them. Authorship identification is concerned with determining the likelihood of a particular author having written some piece(s) of code. usually based on other code samples from the same programmer. Java is a popular object-oriented computer programming language. Programming fingerprints attempt to characterize the features that are unique to each programmer. In this study, we investigated the extraction of a set of software metrics of a given Java source code--by a program written in Visual C++ that could be used as a fingerprint to identify the author of the Java code. The contributions of the selected metrics to authorship identification were measured by a statistical process, namely canonical discriminant analysis, using the statistical software package SAS. Out of the 56 extracted metrics, 48 metrics were identified as being contributive to authorship identification. The authorship of 62.6-67.2% of the Java programs considered could be correctly identified with the extracted metrics. The identification rate could be as high as 85.8%, with derived canonical variates. Moreover. layout metrics played a more important role in authorship identification than the other metrics.
Health and GIS: Toward Spatial Statistical Analyses
Authors: Kyusuk Chung, Duck-Hye Yang, Ralph Bell
Venue: Journal of Medical Systems (2004)

This study examined the extent to which health studies, mostly in public health and epidemiology, used geographical information systems (GIS). We identified a wide range of tools they used&mdash;ranging from geocoding through simple buffer/overlay functions to spatial query functions. However, studies tend to rely on tools outside of GIS for spatial statistical analyses. This may reflect a lack of spatial statistical tools that are suitable for health researchers whose data are rather geographically aggregated count data than continuous data. Implementation within GIS of spatial analytical tools suitable for aggregated data over a region will increase the use of GIS beyond simple GIS operations in health studies.
Desktop Linux: Where Art Thou?
Authors: Bart Decrem
Venue: Queue (2004)

Linux on the desktop has come a long way - and it's been a roller-coaster ride. At the height of the dot-com boom, around the time of Red Hat's initial public offering, people expected Linux to take off on the desktop in short order. A few years later, after the stock market crash and the failure of a couple of high-profile Linux companies, pundits were quick to proclaim the stillborn death of Linux on the desktop.
FastR: Fast Database Search Tool for Non-Coding RNA
Authors: Vineet Bafna, Shaojie Zhang
Venue: Proceedings of the 2004 IEEE Computational Systems Bioinformatics Conference (2004)

The discovery of novel non-coding RNAs has been among the most exciting recent developments in Biology. Yet, many more remain undiscovered. It has been hypothesized that there is in fact an abundance of functional non-coding RNA (ncRNA) with various catalytic and regulatory functions. Computational methods tailored specifically for ncRNA are being actively developed. As the inherent signal for ncRNA is weaker than that for protein coding genes, comparative methods offer the most promising approach, and are the subject of our research. We consider the following problem: Given an RNA sequence with a known secondary structure, efficiently compute all structural homologs (computed as a function of sequence and structural similarity) in a genomic database. Our approach, based on structural filters that eliminate a large portion of the database, while retaining the true homologs allows us to search a typical bacterial database in minutes on a standard PC, with high sensitivity and specificity. This is two orders of magnitude better than current available software for the problem.
A new PCP outer verifier with applications to homogeneous linear equations and max-bisection
Authors: Jonas Holmerin, Subhash Khot
Venue: Proceedings of the thirty-sixth annual ACM symposium on Theory of computing (2004)

We show an optimal hardness result for the following problem: Given a system of homogeneous linear equations over GF(2) with 3 variables per equation, find a balanced assignment that satisfies maximum number of equations. For arbitrarily small constant ζ > 0, we show that it is hard to determine (in polynomial time) whether such a system has a balanced assignment that satisfies 1-ζ fraction of equations or there is no balanced assignment that satisfies more than ½+ζ fraction of equations. As a corollary, we show that it is hard to approximate (in polynomial time) the Max-Bisection problem within factor 16⁄15-ζ. These hardness results hold under the assumption NP ⊈ ∩ε > 0 DTIME(2nε).Our results are obtained via a construction of a new PCP outer verifier that has a mixing property and a smoothness property. These properties are crucial in the analysis of the inner verifier. No previous outer verifier can achieve both these properties simultaneously. An outer verifier is essentially a 2-query PCP over a large alphabet. Loosely speaking, the mixing property says that the locations of the two queries read by the verifier are uncorrelated. The smoothness property says that the verifier's acceptance predicate is close to being a bijective predicate. Our construction relies on the algebraic techniques used to prove the PCP Theorem. This is in contrast with all earlier constructions that use the PCP Theorem as a black-box. The progress in inapproximability theory seems to require new ideas for building outer verifiers and our construction takes a first step in that direction.
Effect of fixed dielectric charges on tunnelling transparency in MIM and MIS structures
Authors: S. Bernardini, P. Masson, M. Houssa
Venue: Microelectronic Engineering (2004)

Charges trapped within the gate dielectric layer, are known to result in substantial changes in electrical properties of Metal-Insulator-Semiconductor structures. In this paper, we present simulation results of tunnelling transparency for single insulator metal/SiO2/metal structures and double insulator silicon/SiO2/HfO2/metal structures using our own simulator. The simulations allow to predict the impact of fixed dielectric charges on tunnelling barrier shape and the modification of the Fowler-Nordheim injection parameters in MIM and MIS structures.
Coaching Academic English through voice and text production models
Authors: Caroline Greenman
Venue: ReCALL (2004)

We report on how technological developments have enabled us to change our concepts and practices regarding voice and text coaching and how this in turn has raised the level of literary competence among non-native doctoral students seeking publication in English in scientific journals. We describe models for marking, peer reviewing and coaching spoken delivery and written text. Our models spring from our dedicated physical CALL environment and take into account learner expectations and further develop tangible learner strategies. As our models are applied in an open learning platform they are accessible, interactive and facilitate both differentiated progressive feedback and student profiling. The four skills are revisited through very traditional means in a methodological paradigm requiring some &lsquo;new literacy&rsquo;. Between 1997 and 2000 we were devoted to developing and testing our dedicated physical CALL classroom model; in the period 2000&ndash;2003 we have focused on both sustaining this and improving our procedures. Refining the coaching and interactive feedback procedures for both text and voice development within the virtual classroom model (established at the Institute for Living Languages at KULeuven in 1997) informs the focus of our research. During the latter period, the resulting models have been rigorously tested by about three hundred KULeuven students, half of whom are post graduates and half of whom are undergraduates. The specific need for refined coaching and feedback for doctoral students is first defined, then the concept, procedure and results of three models are outlined and illustrated. The models include a text marking and coaching model, a speech marking and coaching model and a model to contextualise and manage the interactive cycle of learner, peer and coach writing and speaking processes. Key to our findings is the fact that our models help us to help learners differentiate between passive and active retrieval, plus transfer issues versus knowledge gap issues. The discussion centres on further model development integration.
Representing the zoo world and the traffic world in the language of the causal calculator
Authors: Varol Akman, Selim T. Erdoǧan, Joohyung Lee, Vladimir Lifschitz, Hudson Turner
Venue: Artificial Intelligence (2004)

The work described in this report is motivated by the desire to test the expressive possibilities of action language C+. The Causal Calculator (CCALC) is a system that answers queries about action domains described in a fragment of that language. The Zoo World and the Traffic World have been proposed by Erik Sandewall in his Logic Modelling Workshop--an environment for communicating axiomatizations of action domains of nontrivial size.The Zoo World consists of several cages and the exterior, gates between them, and animals of several species, including humans. Actions in this domain include moving within and between cages, opening and closing gates, and mounting and riding animals. The Traffic World includes vehicles moving continuously between road crossings subject to a number of restrictions, such as speed limits and keeping a fixed safety distance away from other vehicles on the road. We show how to represent the two domains in the input language of CCALC, and how to use CCALC to test these representations.
Circuit Simulation of Nanotechnology Devices with Non-monotonic I-V Characteristics
Authors: Jiayong Le, Larry Pileggi, Anirudh Devgan
Venue: Proceedings of the 2003 IEEE/ACM international conference on Computer-aided design (2003)

As research begins to explore potential nanotechnologiesfor future post-CMOS integrated systems, modeling andsimulation environments must be developed that canaccommodate the corresponding problem complexity and non-traditionaldevice characteristics. This paper describes a circuit-levelsimulator that can accommodate an important class ofnanotechnology devices that are characterized by non-monotonicI-V characteristics. Employing adaptively controlledexplicit integration method (ACES) and piecewise linear (PWL)device models, the proposed approach effectively overcomesthe convergence problems and multiple equilibrium pointsolution problems caused by the Negative DifferentialResistance (NDR) regions in such device I-V functions.Importantly, the ACES approach can address the circuit sizeproblem when partitioning is included, and providecompatibility with simple I-V device model tables, therebyavoiding the need for analytical device models that rarely areavailable for nanotechnology devices.
An Architecture for Real-Time Active Content Distribution
Authors: Chengdu Huang, Seejo Sebastine, Tarek Abdelzaher
Venue: Proceedings of the 16th Euromicro Conference on Real-Time Systems (2004)

The phenomenal growth of the world-wide web has made itthe most popular Internet application today. Web cachingand content distribution services have been recognized asvaluable techniques to mitigate the explosion of web traffic. An increasing fraction of web traffic today is dynamicallygenerated and therefore intrinsically difficult for replicationusing present static approaches. Scalable delivery ofsuch active content poses a myriad of challenges, includingcontent replication, update propagation, and consistencymanagement. This paper makes two contributions: (1)it describes a scalable architecture for transparent demand-drivendistribution of active content; (2) the system can providereal-time delay guarantee on content access. Our approachinvolves migrating the scripts which generate the dynamicweb traffic, and their data, from the server to activecontent distribution proxies nearest to the clients and mechanismson these proxies to enforce real-time delay guaranteesfor client requests. Our system is implemented and deployedon PlanetLab [19], a real-world distributed Internettestbed. Experimental data show that significant improvementsare observed in effective throughput and client responsetime, and delay bounds on content access can beguaranteed with a very high probability.
Hardware assisted high level debugging: preliminary draft
Authors: W. Morven Gentleman, Henry Hoeksma
Venue: ACM SIGSOFT Software Engineering Notes (1983)

Hardware assistance has long been used for logic level and functional unit level hardware debugging, as well as for machine language level software debugging. Such hardware assistance includes probes to detect signals, comparators to identify matches with expected patterns, buffers to record selected events, and independent logic and software to analyze and interpret the observed events. It can also include the ability to generate selected signals to stimulate the object being debugged and the ability to isolate it from normal changes so its state can be examined. Through knowledge of the data structures and algorithms used by the operating systems, and the runtime representation, register usage, and code bursts produced by compilers, it is possible to take advantage of such hardware assistance in high-level debugging. High level debugging here refers to debugging in terms of abstractions supported by the operating system and programming languages, as well as user defined abstractions built on top of these.
Experiences with teaching design patterns
Authors: Sylvia Stuurman, Gert Florijn
Venue: ACM SIGCSE Bulletin (2004)

In this paper, we present an assignment for a course on Design patterns at the masters level, where students have to adapt an existing program to meet additional requirements. We describe the basic program, discuss the reasons why we decided for such an assignment, and show the results. The assignment proved to be very effective both to train students to work with design patterns and to assess that students have reached the learning goals. This was true both for students with a professional background and for students with academic interests.
An exact algorithm for the robust shortest path problem with interval data
Authors: R. Montemanni, L. M. Gambardella
Venue: Computers and Operations Research (2004)

The robust deviation shortest path problem with interval data is studied in this paper.After the formulation of the problem in mathematical terms, an exact algorithm, based on a very simple concept, is described. Some practical improvements to the basic idea, which speed up the method, are also presented.Computational results corroborate the correctness of the conjecture on which the algorithnt is based and the potential of the approach. In particular, our method is proven to be able to retrieve high-quality solutions very quickly on some families of networks. For this reason, it could alternatively be used as a fast heuristic method.