OpenRaiser/Intern-Atlas huggingface dataset:
Global Platform for Rich Media Conferencing and Collaboration
Venue: arXiv cs.MM 2003
Year: 2003

The Virtual Rooms Videoconferencing Service (VRVS) provides a worldwide videoconferencing service and collaborative environment to the research and education communities. This system provides a low cost, bandwidth-efficient, extensible means for videoconferencing and remote collaboration over networks within the High Energy and Nuclear Physics communities (HENP). VRVS has become a standard part of the toolset used daily by a large sector of HENP, and it is used increasingly for other DoE/NSF-supported programs. The current features included multi-protocol, multi-OS support for all significant video enabled clients including: H.323, Mbone, QuickTime, MPEG2, Java Media Framework, and other clients. The current architecture makes VRVS a distributed, highly functional, and efficient software-only system for multipoint audio, video and web conferencing and collaboration over global IP networks. VRVS has developed the VRVS-AG Reflector and a specialized Web interface that enables end users to connect to any Access Grid (AG) session, in any of the AG "virtual venues" from anywhere worldwide. The VRVS system has now been running for the last five and half years, offering to the HENP community a working and reliable tool for collaboration within groups and among physicists dispersed world-wide. The goal of this ongoing effort is to develop the next generation collaborative systems running over next generation networks. The new developments area integrate emerging standards, include all security aspects, and will extend the range of VRVS video technologies supported to cover the latest high end standards quality. We will focus the discussion on the new capability provides by the latest version V3.0 and its future evolution.
Security for Grid Services
Venue: arXiv cs.CR 2003
Year: 2003

Grid computing is concerned with the sharing and coordinated use of diverse resources in distributed "virtual organizations." The dynamic and multi-institutional nature of these environments introduces challenging security issues that demand new technical approaches. In particular, one must deal with diverse local mechanisms, support dynamic creation of services, and enable dynamic creation of trust domains. We describe how these issues are addressed in two generations of the Globus Toolkit. First, we review the Globus Toolkit version 2 (GT2) approach; then, we describe new approaches developed to support the Globus Toolkit version 3 (GT3) implementation of the Open Grid Services Architecture, an initiative that is recasting Grid concepts within a service oriented framework based on Web services. GT3's security implementation uses Web services security mechanisms for credential exchange and other purposes, and introduces a tight least-privilege model that avoids the need for any privileged network service.
Anusaaraka: Machine Translation in Stages
Venue: arXiv cs.CL 2003
Year: 2003

Fully-automatic general-purpose high-quality machine translation systems (FGH-MT) are extremely difficult to build. In fact, there is no system in the world for any pair of languages which qualifies to be called FGH-MT. The reasons are not far to seek. Translation is a creative process which involves interpretation of the given text by the translator. Translation would also vary depending on the audience and the purpose for which it is meant. This would explain the difficulty of building a machine translation system. Since, the machine is not capable of interpreting a general text with sufficient accuracy automatically at present - let alone re-expressing it for a given audience, it fails to perform as FGH-MT. FOOTNOTE{The major difficulty that the machine faces in interpreting a given text is the lack of general world knowledge or common sense knowledge.}
Pruning Isomorphic Structural Sub-problems in Configuration
Venue: arXiv cs.AI 2003
Year: 2003

Configuring consists in simulating the realization of a complex product from a catalog of component parts, using known relations between types, and picking values for object attributes. This highly combinatorial problem in the field of constraint programming has been addressed with a variety of approaches since the foundation system R1(McDermott82). An inherent difficulty in solving configuration problems is the existence of many isomorphisms among interpretations. We describe a formalism independent approach to improve the detection of isomorphisms by configurators, which does not require to adapt the problem model. To achieve this, we exploit the properties of a characteristic subset of configuration problems, called the structural sub-problem, which canonical solutions can be produced or tested at a limited cost. In this paper we present an algorithm for testing the canonicity of configurations, that can be added as a symmetry breaking constraint to any configurator. The cost and efficiency of this canonicity test are given.
Eprints and the Open Archives Initiative
Venue: arXiv cs.DL 2003
Year: 2003

The Open Archives Initiative (OAI) was created as a practical way to promote interoperability between eprint repositories. Although the scope of the OAI has been broadened, eprint repositories still represent a significant fraction of OAI data providers. In this article I present a brief survey of OAI eprint repositories, and of services using metadata harvested from eprint repositories using the OAI protocol for metadata harvesting (OAI-PMH). I then discuss several situations where metadata harvesting may be used to further improve the utility of eprint archives as a component of the scholarly communication infrastructure.
Syntax, Parsing and Production of Natural Language in a Framework of Information Compression by Multiple Alignment, Unification and Search
Venue: arXiv cs.AI 2003
Year: 2003

This article introduces the idea that "information compression by multiple alignment, unification and search" (ICMAUS) provides a framework within which natural language syntax may be represented in a simple format and the parsing and production of natural language may be performed in a transparent manner. The ICMAUS concepts are embodied in a software model, SP61. The organisation and operation of the model are described and a simple example is presented showing how the model can achieve parsing of natural language. Notwithstanding the apparent paradox of 'decompression by compression', the ICMAUS framework, without any modification, can produce a sentence by decoding a compressed code for the sentence. This is illustrated with output from the SP61 model. The article includes four other examples - one of the parsing of a sentence in French and three from the domain of English auxiliary verbs. These examples show how the ICMAUS framework and the SP61 model can accommodate 'context sensitive' features of syntax in a relatively simple and direct manner.
Tools and Techniques for Managing Clusters for SciDAC Lattice QCD at Fermilab
Venue: arXiv cs.DC 2003
Year: 2003

Fermilab operates several clusters for lattice gauge computing. Minimal manpower is available to manage these clusters. We have written a number of tools and developed techniques to cope with this task. We describe our tools which use the IPMI facilities of our systems for hardware management tasks such as remote power control, remote system resets, and health monitoring. We discuss our techniques involving network booting for installation and upgrades of the operating system on these computers, and for reloading BIOS and other firmware. Finally, we discuss our tools for parallel command processing and their use in monitoring and administrating the PBS batch queue system used on our clusters.
A Note on Objects Built From Bricks without Corners
Venue: arXiv cs.CG 2003
Year: 2003

We report a small advance on a question raised by Robertson, Schweitzer, and Wagon in [RSW02]. They constructed a genus-13 polyhedron built from bricks without corners, and asked whether every genus-0 such polyhedron must have a corner. A brick is a parallelopiped, and a corner is a brick of degree three or less in the brick graph. We describe a genus-3 polyhedron built from bricks with no corner, narrowing the genus gap.
Boundary knot method for Laplace and biharmonic problems
Venue: arXiv cs.CE 2003
Year: 2003

The boundary knot method (BKM) [1] is a meshless boundary-type radial basis function (RBF) collocation scheme, where the nonsingular general solution is used instead of fundamental solution to evaluate the homogeneous solution, while the dual reciprocity method (DRM) is employed to approximation of particular solution. Despite the fact that there are not nonsingular RBF general solutions available for Laplace and biharmonic problems, this study shows that the method can be successfully applied to these problems. The high-order general and fundamental solutions of Burger and Winkler equations are also first presented here.
Application of interactive parallel visualization for commodity-based clusters using visualization APIs
Venue: arXiv cs.GR 2003
Year: 2003

We present an efficient and inexpensive to develop application for interactive high-performance parallel visualization. We extend popular APIs such as Open Inventor and VTK to support commodity-based cluster visualization. Our implementation follows a standard master/slave concept: the general idea is to have a ``Master'' node, which will intercept a sequential graphical user interface (GUI) and broadcast it to the ``Slave'' nodes. The interactions between the nodes are implemented using MPI. The parallel remote rendering uses Chromium. This paper is mainly the report of our implementation experiences. We present in detail the proposed model and key aspects of its implementation. Also, we present performance measurements, we benchmark and quantitatively demonstrate the dependence of the visualization speed on the data size and the network bandwidth, and we identify the singularities and draw conclusions on Chromium's sort-first rendering architecture. The most original part of this work is the combined use of Open Inventor and Chromium.
Modeling Belief in Dynamic Systems, Part I: Foundations
Venue: arXiv cs.AI 2003
Year: 2003

Belief change is a fundamental problem in AI: Agents constantly have to update their beliefs to accommodate new observations. In recent years, there has been much work on axiomatic characterizations of belief change. We claim that a better understanding of belief change can be gained from examining appropriate semantic models. In this paper we propose a general framework in which to model belief change. We begin by defining belief in terms of knowledge and plausibility: an agent believes p if he knows that p is more plausible than its negation. We then consider some properties defining the interaction between knowledge and plausibility, and show how these properties affect the properties of belief. In particular, we show that by assuming two of the most natural properties, belief becomes a KD45 operator. Finally, we add time to the picture. This gives us a framework in which we can talk about knowledge, plausibility (and hence belief), and time, which extends the framework of Halpern and Fagin for modeling knowledge in multi-agent systems. We then examine the problem of ``minimal change''. This notion can be captured by using prior plausibilities, an analogue to prior probabilities, which can be updated by ``conditioning''. We show by example that conditioning on a plausibility measure can capture many scenarios of interest. In a companion paper, we show how the two best-studied scenarios of belief change, belief revisionand belief update, fit into our framework.
Rethinking OpenPGP PKI and OpenPGP Public Keyserver
Venue: arXiv cs.CY 2003
Year: 2003

OpenPGP, an IETF Proposed Standard based on PGP application, has its own Public Key Infrastructure (PKI) architecture which is different from the one based on X.509, another standard from ITU. This paper describes the OpenPGP PKI; the historical perspective as well as its current use. The current OpenPGP PKI issues include the capability of a PGP keyserver and its performance. PGP keyservers have been developed and operated by volunteers since the 1990s. The keyservers distribute, merge, and expire the OpenPGP public keys. Major keyserver managers from several countries have built the globally distributed network of PGP keyservers. However, the current PGP Public Keyserver (pksd) has some limitations. It does not support fully the OpenPGP format so that it is neither expandable nor flexible, without any cluster technology. Finally we introduce the project on the next generation OpenPGP public keyserver called the OpenPKSD, lead by Hironobu Suzuki, one of the authors, and funded by Japanese Information-technology Promotion Agency(IPA).
Anusaaraka: Overcoming the Language Barrier in India
Venue: arXiv cs.CL 2003
Year: 2003

The anusaaraka system makes text in one Indian language accessible in another Indian language. In the anusaaraka approach, the load is so divided between man and computer that the language load is taken by the machine, and the interpretation of the text is left to the man. The machine presents an image of the source text in a language close to the target language.In the image, some constructions of the source language (which do not have equivalents) spill over to the output. Some special notation is also devised. The user after some training learns to read and understand the output. Because the Indian languages are close, the learning time of the output language is short, and is expected to be around 2 weeks. The output can also be post-edited by a trained user to make it grammatically correct in the target language. Style can also be changed, if necessary. Thus, in this scenario, it can function as a human assisted translation system. Currently, anusaarakas are being built from Telugu, Kannada, Marathi, Bengali and Punjabi to Hindi. They can be built for all Indian languages in the near future. Everybody must pitch in to build such systems connecting all Indian languages, using the free software model.
Model Checking Linear Logic Specifications
Venue: arXiv cs.PL 2003
Year: 2003

The overall goal of this paper is to investigate the theoretical foundations of algorithmic verification techniques for first order linear logic specifications. The fragment of linear logic we consider in this paper is based on the linear logic programming language called LO enriched with universally quantified goal formulas. Although LO was originally introduced as a theoretical foundation for extensions of logic programming languages, it can also be viewed as a very general language to specify a wide range of infinite-state concurrent systems. Our approach is based on the relation between backward reachability and provability highlighted in our previous work on propositional LO programs. Following this line of research, we define here a general framework for the bottom-up evaluation of first order linear logic specifications. The evaluation procedure is based on an effective fixpoint operator working on a symbolic representation of infinite collections of first order linear logic formulas. The theory of well quasi-orderings can be used to provide sufficient conditions for the termination of the evaluation of non trivial fragments of first order linear logic.
The Structure of Information
Venue: arXiv cs.LO 2003
Year: 2003

A formal model of the structure of information is presented in five axioms which define identity, containment, and joins of infons. Joins are shown to be commutative, associative, provide inverses of infons, and, potentially, have many identity elements, two of which are multiplicative and additive. Those two types of join are distributive. The other identity elements are for operators on entwined states. Multiplicative joins correspond to adding or removing new bits to a system while additive joins correspond to a change of state. The order or size of an infon is defined. This groundwork is intended to be used to model continuous and discreet information structures through time, especially in closed systems.
Lower bounds for predecessor searching in the cell probe model
Venue: arXiv cs.CC 2003
Year: 2003

We consider a fundamental problem in data structures, static predecessor searching: Given a subset S of size n from the universe [m], store S so that queries of the form "What is the predecessor of x in S?" can be answered efficiently. We study this problem in the cell probe model introduced by Yao. Recently, Beame and Fich obtained optimal bounds on the number of probes needed by any deterministic query scheme if the associated storage scheme uses only n^{O(1)} cells of word size (\log m)^{O(1)} bits. We give a new lower bound proof for this problem that matches the bounds of Beame and Fich. Our lower bound proof has the following advantages: it works for randomised query schemes too, while Beame and Fich's proof works for deterministic query schemes only. It also extends to `quantum address-only' query schemes that we define in this paper, and is simpler than Beame and Fich's proof. We prove our lower bound using the round elimination approach of Miltersen, Nisan, Safra and Wigderson. Using tools from information theory, we prove a strong round elimination lemma for communication complexity that enables us to obtain a tight lower bound for the predecessor problem. Our strong round elimination lemma also extends to quantum communication complexity. We also use our round elimination lemma to obtain a rounds versus communication tradeoff for the `greater-than' problem, improving on the tradeoff in Miltersen et al. We believe that our round elimination lemma is of independent interest and should have other applications.
Combining Independent Modules to Solve Multiple-choice Synonym and Analogy Problems
Venue: arXiv cs.CL 2003
Year: 2003

Existing statistical approaches to natural language problems are very coarse approximations to the true complexity of language processing. As such, no single technique will be best for all problem instances. Many researchers are examining ensemble methods that combine the output of successful, separately developed modules to create more accurate solutions. This paper examines three merging rules for combining probability distributions: the well known mixture rule, the logarithmic rule, and a novel product rule. These rules were applied with state-of-the-art results to two problems commonly used to assess human mastery of lexical semantics -- synonym questions and analogy questions. All three merging rules result in ensembles that are more accurate than any of their component modules. The differences among the three rules are not statistically significant, but it is suggestive that the popular mixture rule is not the best rule for either of the two problems.
Two novel evolutionary formulations of the graph coloring problem
Venue: arXiv cs.NE 2003
Year: 2003

We introduce two novel evolutionary formulations of the problem of coloring the nodes of a graph. The first formulation is based on the relationship that exists between a graph's chromatic number and its acyclic orientations. It views such orientations as individuals and evolves them with the aid of evolutionary operators that are very heavily based on the structure of the graph and its acyclic orientations. The second formulation, unlike the first one, does not tackle one graph at a time, but rather aims at evolving a `program' to color all graphs belonging to a class whose members all have the same number of nodes and other common attributes. The heuristics that result from these formulations have been tested on some of the Second DIMACS Implementation Challenge benchmark graphs, and have been found to be competitive when compared to the several other heuristics that have also been tested on those graphs.
Causes and Effects in Computer Programs
Venue: arXiv cs.SE 2003
Year: 2003

Debugging is commonly understood as finding and fixing the cause of a problem. But what does ``cause'' mean? How can we find causes? How can we prove that a cause is a cause--or even ``the'' cause? This paper defines common terms in debugging, highlights the principal techniques, their capabilities and limitations.
Control and Debugging of Distributed Programs Using Fiddle
Venue: arXiv cs.DC 2003
Year: 2003

The main goal of Fiddle, a distributed debugging engine, is to provide a flexible platform for developing debugging tools. Fiddle provides a layered set of interfaces with a minimal set of debugging functionalities, for the inspection and control of distributed and multi-threaded applications. This paper illustrates how Fiddle is used to support integrated testing and debugging. The approach described is based on a tool, called Deipa, that interprets sequences of commands read from an input file, generated by an independent testing tool. Deipa acts as a Fiddle client, in order to enforce specific execution paths in a distributed PVM program. Other Fiddle clients may be used along with Deipa for the fine debugging at process level. Fiddle and Deipa functionalities and architectures are described, and a working example shows a step-by-step application of these tools.
Minimal DFAs for Testing Divisibility
Venue: arXiv cs.CC 2003
Year: 2003

We present and prove a theorem answering the question "how many states does a minimal deterministic finite automaton (DFA) that recognizes the set of base-b numbers divisible by k have?"
A mathematical framework for automated bug localization
Venue: arXiv cs.SE 2003
Year: 2003

In this paper, we propose a mathematical framework for automated bug localization. This framework can be briefly summarized as follows. A program execution can be represented as a rooted acyclic directed graph. We define an execution snapshot by a cut-set on the graph. A program state can be regarded as a conjunction of labels on edges in a cut-set. Then we argue that a debugging task is a pruning process of the execution graph by using cut-sets. A pruning algorithm, i.e., a debugging task, is also presented.
A Formal Comparison of Visual Web Wrapper Generators
Venue: arXiv cs.DB 2003
Year: 2003

We study the core fragment of the Elog wrapping language used in the Lixto system (a visual wrapper generator) and formally compare Elog to other wrapping languages proposed in the literature.
Debugging Tool for Localizing Faulty Processes in Message Passing Programs
Venue: arXiv cs.SE 2003
Year: 2003

In message passing programs, once a process terminates with an unexpected error, the terminated process can propagate the error to the rest of processes through communication dependencies, resulting in a program failure. Therefore, to locate faults, developers must identify the group of processes involved in the original error and faulty processes that activate faults. This paper presents a novel debugging tool, named MPI-PreDebugger (MPI-PD), for localizing faulty processes in message passing programs. MPI-PD automatically distinguishes the original and the propagated errors by checking communication errors during program execution. If MPI-PD observes any communication errors, it backtraces communication dependencies and points out potential faulty processes in a timeline view. We also introduce three case studies, in which MPI-PD has been shown to play the key role in their debugging. From these studies, we believe that MPI-PD helps developers to locate faults and allows them to concentrate in correcting their programs.
Pure Prolog Execution in 21 Rules
Venue: arXiv cs.PL 2003
Year: 2003

A simple mathematical definition of the 4-port model for pure Prolog is given. The model combines the intuition of ports with a compact representation of execution state. Forward and backward derivation steps are possible. The model satisfies a modularity claim, making it suitable for formal reasoning.