OpenRaiser/Intern-Atlas huggingface dataset:
Theoretical study of cache syatems
Venue: arXiv cs.NI 2003
Year: 2003

The aim of this paper is a theoretical study of a cache system in order to optimize proxy cache systems and to modernize construction principles including prefetching schemes. Two types of correlations, Zipf-like distribution and normalizing conditions, play a role of the fundamental laws. A corresponding system of equations allows to describe the basic effects like ratio between construction parts, steady-state performance, optimal size, long-term prefetching, etc. A modification of the fundamental laws leads to the description of new effects of documents' renewal in the global network. An internet traffic caching system based on Zipf-like distribution (ZBS) is invented. The additional module to the cache construction gives an effective prefetching by lifetime.
A Development Calculus for Specifications
Venue: arXiv cs.LO 2003
Year: 2003

A first order inference system, called R-calculus, is defined to develop the specifications. It is used to eliminate the laws which is not consistent with the user's requirements. The R-calculus consists of the structural rules, an axiom, a cut rule, and the rules for logical connectives. Some examples are given to demonstrate the usage of the R-calculus. The properties about reachability and completeness of the R-calculus are formally defined and are proved.
Probabilistic behavior of hash tables
Venue: arXiv cs.DS 2003
Year: 2003

We extend a result of Goldreich and Ron about estimating the collision probability of a hash function. Their estimate has a polynomial tail. We prove that when the load factor is greater than a certain constant, the estimator has a gaussian tail. As an application we find an estimate of an upper bound for the average search time in hashing with chaining, for a particular user (we allow the overall key distribution to be different from the key distribution of a particular user). The estimator has a gaussian tail.
Numerical Coverage Estimation for the Symbolic Simulation of Real-Time Systems
Venue: arXiv cs.SE 2003
Year: 2003

Three numerical coverage metrics for the symbolic simulation of dense-time systems and their estimation methods are presented. Special techniques to derive numerical estimations of dense-time state-spaces have also been developed. Properties of the metrics are also discussed with respect to four criteria. Implementation and experiments are then reported.
The Mad Hatter´s Cocktail Party: A Social Mobile Audio Space Supporting Multiple Simultaneous Conversations
Venue: arXiv cs.HC 2003
Year: 2003

This paper presents a mobile audio space intended for use by gelled social groups. In face-to-face interactions in such social groups, conversational floors change frequently, e.g., two participants split off to form a new conversational floor, a participant moves from one conversational floor to another, etc. To date, audio spaces have provided little support for such dynamic regroupings of participants, either requiring that the participants explicitly specify with whom they wish to talk or simply presenting all participants as though they are in a single floor. By contrast, the audio space described here monitors participant behavior to identify conversational floors as they emerge. The system dynamically modifies the audio delivered to each participant to enhance the salience of the participants with whom they are currently conversing. We report a user study of the system, focusing on conversation analytic results.
Stochastic Volatility in a Quantitative Model of Stock Market Returns
Venue: arXiv cs.CE 2003
Year: 2003

Standard quantitative models of the stock market predict a log-normal distribution for stock returns (Bachelier 1900, Osborne 1959), but it is recognised (Fama 1965) that empirical data, in comparison with a Gaussian, exhibit leptokurtosis (it has more probability mass in its tails and centre) and fat tails (probabilities of extreme events are underestimated). Different attempts to explain this departure from normality have coexisted. In particular, since one of the strong assumptions of the Gaussian model concerns the volatility, considered finite and constant, the new models were built on a non finite (Mandelbrot 1963) or non constant (Cox, Ingersoll and Ross 1985) volatility. We investigate in this thesis a very recent model (Dragulescu et al. 2002) based on a Brownian motion process for the returns, and a stochastic mean-reverting process for the volatility. In this model, the forward Kolmogorov equation that governs the time evolution of returns is solved analytically. We test this new theory against different stock indexes (Dow Jones Industrial Average, Standard and Poor s and Footsie), over different periods (from 20 to 105 years). Our aim is to compare this model with the classical Gaussian and with a simple Neural Network, used as a benchmark. We perform the usual statistical tests on the kurtosis and tails of the expected distributions, paying particular attention to the outliers. As claimed by the authors, the new model outperforms the Gaussian for any time lag, but is artificially too complex for medium and low frequencies, where the Gaussian is preferable. Moreover this model is still rejected for high frequencies, at a 0.05 level of significance, due to the kurtosis, incorrectly handled.
"I'm sorry Dave, I'm afraid I can't do that": Linguistics, Statistics, and Natural Language Processing circa 2001
Venue: arXiv cs.CL 2003
Year: 2003

A brief, general-audience overview of the history of natural language processing, focusing on data-driven approaches.Topics include "Ambiguity and language analysis", "Firth things first", "A 'C' change", and "The empiricists strike back".
A New Account of Personalization and Effective Communication
Venue: arXiv cs.CY 2003
Year: 2003

To contribute to understanding of information economies of daily life, this paper explores over the past millennium given names of a large number of persons. Analysts have long both condemned and praised mass media as a source of common culture, national unity, or shared symbolic experiences. Names, however, indicate a large decline in shared symbolic experience over the past two centuries, a decline that the growth of mass media does not appear to have affected significantly. Study of names also shows that action and personal relationships, along with time horizon, are central aspects of effective communication across a large population. The observed preference for personalization over the past two centuries and the importance of action and personal relationships to effective communication are aspects of information economies that are likely to have continuing significance for industry developments, economic statistics, and public policy.
gTybalt - a free computer algebra system
Venue: arXiv cs.SC 2003
Year: 2003

This article documents the free computer algebra system "gTybalt". The program is build on top of other packages, among others GiNaC, TeXmacs and Root. It offers the possibility of interactive symbolic calculations within the C++ programming language. Mathematical formulae are visualized using TeX fonts.
Distributed States Temporal Logic
Venue: arXiv cs.LO 2003
Year: 2003

We introduce a temporal logic to reason on global applications in an asynchronous setting. First, we define the Distributed States Logic (DSL), a modal logic for localities that embeds the local theories of each component into a theory of the distributed states of the system. We provide the logic with a sound and complete axiomatization. The contribution is that it is possible to reason about properties that involve several components, even in the absence of a global clock. Then, we define the Distributed States Temporal Logic (DSTL) by introducing temporal operators a' la Unity. We support our proposal by working out a pair of examples: a simple secure communication system, and an algorithm for distributed leader election. The motivation for this work is that the existing logics for distributed systems do not have the right expressive power to reason on the systems behaviour, when the communication is based on asynchronous message passing. On the other side, asynchronous communication is the most used abstraction when modelling global applications.
Approximate Grammar for Information Extraction
Venue: arXiv cs.CL 2003
Year: 2003

In this paper, we present the concept of Approximate grammar and how it can be used to extract information from a documemt. As the structure of informational strings cannot be defined well in a document, we cannot use the conventional grammar rules to represent the information. Hence, the need arises to design an approximate grammar that can be used effectively to accomplish the task of Information extraction. Approximate grammars are a novel step in this direction. The rules of an approximate grammar can be given by a user or the machine can learn the rules from an annotated document. We have performed our experiments in both the above areas and the results have been impressive.
Fast Dempster-Shafer clustering using a neural network structure
Venue: arXiv cs.AI 2003
Year: 2003

In this paper we study a problem within Dempster-Shafer theory where 2**n - 1 pieces of evidence are clustered by a neural structure into n clusters. The clustering is done by minimizing a metaconflict function. Previously we developed a method based on iterative optimization. However, for large scale problems we need a method with lower computational complexity. The neural structure was found to be effective and much faster than iterative optimization for larger problems. While the growth in metaconflict was faster for the neural structure compared with iterative optimization in medium sized problems, the metaconflict per cluster and evidence was moderate. The neural structure was able to find a global minimum over ten runs for problem sizes up to six clusters.
A neural network and iterative optimization hybrid for Dempster-Shafer clustering
Venue: arXiv cs.AI 2003
Year: 2003

In this paper we extend an earlier result within Dempster-Shafer theory ["Fast Dempster-Shafer Clustering Using a Neural Network Structure," in Proc. Seventh Int. Conf. Information Processing and Management of Uncertainty in Knowledge-Based Systems (IPMU 98)] where a large number of pieces of evidence are clustered into subsets by a neural network structure. The clustering is done by minimizing a metaconflict function. Previously we developed a method based on iterative optimization. While the neural method had a much lower computation time than iterative optimization its average clustering performance was not as good. Here, we develop a hybrid of the two methods. We let the neural structure do the initial clustering in order to achieve a high computational performance. Its solution is fed as the initial state to the iterative optimization in order to improve the clustering performance.
Conflict-based Force Aggregation
Venue: arXiv cs.AI 2003
Year: 2003

In this paper we present an application where we put together two methods for clustering and classification into a force aggregation method. Both methods are based on conflicts between elements. These methods work with different type of elements (intelligence reports, vehicles, military units) on different hierarchical levels using specific conflict assessment methods on each level. We use Dempster-Shafer theory for conflict calculation between elements, Dempster-Shafer clustering for clustering these elements, and templates for classification. The result of these processes is a complete force aggregation on all levels handled.
Beslutstödssystemet Dezzy - en översikt
Venue: arXiv cs.AI 2003
Year: 2003

Within the scope of the three-year ANTI-SUBMARINE WARFARE project of the National Defence Research Establishment, the INFORMATION SYSTEMS subproject has developed the demonstration prototype Dezzy for handling and analysis of intelligence reports concerning foreign underwater activities. ----- Inom ramen för FOA:s treåriga huvudprojekt UBÅTSSKYDD har delprojekt INFORMATIONSSYSTEM utvecklat demonstrationsprototypen Dezzy till ett beslutsstödsystem för hantering och analys av underrättelser om främmande undervattensverksamhet.
Cryptanalysis of HFE
Venue: arXiv cs.CR 2003
Year: 2003

I transform the trapdoor problem of HFE into a linear algebra problem.
Periodicity and Unbordered Words: A Proof of the Extended Duval Conjecture
Venue: arXiv cs.DM 2003
Year: 2003

The relationship between the length of a word and the maximum length of its unbordered factors is investigated in this paper. Consider a finite word w of length n. We call a word bordered, if it has a proper prefix which is also a suffix of that word. Let f(w) denote the maximum length of all unbordered factors of w, and let p(w) denote the period of w. Clearly, f(w) < p(w)+1. We establish that f(w) = p(w), if w has an unbordered prefix of length f(w) and n > 2f(w)-2. This bound is tight and solves the stronger version of a 21 years old conjecture by Duval. It follows from this result that, in general, n > 3f(w)-3 implies f(w) = p(w) which gives an improved bound for the question asked by Ehrenfeucht and Silberger in 1979.
Bounded LTL Model Checking with Stable Models
Venue: arXiv cs.LO 2003
Year: 2003

In this paper bounded model checking of asynchronous concurrent systems is introduced as a promising application area for answer set programming. As the model of asynchronous systems a generalisation of communicating automata, 1-safe Petri nets, are used. It is shown how a 1-safe Petri net and a requirement on the behaviour of the net can be translated into a logic program such that the bounded model checking problem for the net can be solved by computing stable models of the corresponding program. The use of the stable model semantics leads to compact encodings of bounded reachability and deadlock detection tasks as well as the more general problem of bounded model checking of linear temporal logic. Correctness proofs of the devised translations are given, and some experimental results using the translation and the Smodels system are presented.
The Athena Data Dictionary and Description Language
Venue: arXiv cs.SE 2003
Year: 2003

Athena is the ATLAS off-line software framework, based upon the GAUDI architecture from LHCb. As part of ATLAS' continuing efforts to enhance and customise the architecture to meet our needs, we have developed a data object description tool suite and service for Athena. The aim is to provide a set of tools to describe, manage, integrate and use the Event Data Model at a design level according to the concepts of the Athena framework (use of patterns, relationships, ...). Moreover, to ensure stability and reusability this must be fully independent from the implementation details. After an extensive investigation into the many options, we have developed a language grammar based upon a description language (IDL, ODL) to provide support for object integration in Athena. We have then developed a compiler front end based upon this language grammar, JavaCC, and a Java Reflection API-like interface. We have then used these tools to develop several compiler back ends which meet specific needs in ATLAS such as automatic generation of object converters, and data object scripting interfaces. We present here details of our work and experience to date on the Athena Definition Language and Athena Data Dictionary.
Configuration Database for BaBar On-line
Venue: arXiv cs.DB 2003
Year: 2003

The configuration database is one of the vital systems in the BaBar on-line system. It provides services for the different parts of the data acquisition system and control system, which require run-time parameters. The original design and implementation of the configuration database played a significant role in the successful BaBar operations since the beginning of experiment. Recent additions to the design of the configuration database provide better means for the management of data and add new tools to simplify main configuration tasks. We describe the design of the configuration database, its implementation with the Objectivity/DB object-oriented database, and our experience collected during the years of operation.
R-GMA: First results after deployment
Venue: arXiv cs.DC 2003
Year: 2003

We describe R-GMA (Relational Grid Monitoring Architecture) which is being developed within the European DataGrid Project as an Grid Information and Monitoring System. Is is based on the GMA from GGF, which is a simple Consumer-Producer model. The special strength of this implementation comes from the power of the relational model. We offer a global view of the information as if each VO had one large relational database. We provide a number of different Producer types with different characteristics; for example some support streaming of information. We also provide combined Consumer/Producers, which are able to combine information and republish it. At the heart of the system is the mediator, which for any query is able to find and connect to the best Producers to do the job. We are able to invoke MDS info-provider scripts and publish the resulting information via R-GMA in addition to having some of our own sensors. APIs are available which allow the user to deploy monitoring and information services for any application that may be needed in the future. We have used it both for information about the grid (primarily to find what services are available at any one time) and for application monitoring. R-GMA has been deployed in Grid testbeds, we describe the results and experiences of this deployment.
Managing Dynamic User Communities in a Grid of Autonomous Resources
Venue: arXiv cs.DC 2003
Year: 2003

One of the fundamental concepts in Grid computing is the creation of Virtual Organizations (VO's): a set of resource consumers and providers that join forces to solve a common problem. Typical examples of Virtual Organizations include collaborations formed around the Large Hadron Collider (LHC) experiments. To date, Grid computing has been applied on a relatively small scale, linking dozens of users to a dozen resources, and management of these VO's was a largely manual operation. With the advance of large collaboration, linking more than 10000 users with a 1000 sites in 150 counties, a comprehensive, automated management system is required. It should be simple enough not to deter users, while at the same time ensuring local site autonomy. The VO Management Service (VOMS), developed by the EU DataGrid and DataTAG projects[1, 2], is a secured system for managing authorization for users and resources in virtual organizations. It extends the existing Grid Security Infrastructure[3] architecture with embedded VO affiliation assertions that can be independently verified by all VO members and resource providers. Within the EU DataGrid project, Grid services for job submission, file- and database access are being equipped with fine- grained authorization systems that take VO membership into account. These also give resource owners the ability to ensure site security and enforce local access policies. This paper will describe the EU DataGrid security architecture, the VO membership service and the local site enforcement mechanisms Local Centre Authorization Service (LCAS), Local Credential Mapping Service(LCMAPS) and the Java Trust and Authorization Manager.
Experience with the Open Source based implementation for ATLAS Conditions Data Management System
Venue: arXiv cs.DB 2003
Year: 2003

Conditions Data in high energy physics experiments is frequently seen as every data needed for reconstruction besides the event data itself. This includes all sorts of slowly evolving data like detector alignment, calibration and robustness, and data from detector control system. Also, every Conditions Data Object is associated with a time interval of validity and a version. Besides that, quite often is useful to tag collections of Conditions Data Objects altogether. These issues have already been investigated and a data model has been proposed and used for different implementations based in commercial DBMSs, both at CERN and for the BaBar experiment. The special case of the ATLAS complex trigger that requires online access to calibration and alignment data poses new challenges that have to be met using a flexible and customizable solution more in the line of Open Source components. Motivated by the ATLAS challenges we have developed an alternative implementation, based in an Open Source RDBMS. Several issues were investigated land will be described in this paper: -The best way to map the conditions data model into the relational database concept considering what are foreseen as the most frequent queries. -The clustering model best suited to address the scalability problem. -Extensive tests were performed and will be described. The very promising results from these tests are attracting the attention from the HEP community and driving further developments.
The new BaBar Data Reconstruction Control System
Venue: arXiv cs.DC 2003
Year: 2003

The BaBar experiment is characterized by extremely high luminosity, a complex detector, and a huge data volume, with increasing requirements each year. To fulfill these requirements a new control system has been designed and developed for the offline data reconstruction system. The new control system described in this paper provides the performance and flexibility needed to manage a large number of small computing farms, and takes full benefit of OO design. The infrastructure is well isolated from the processing layer, it is generic and flexible, based on a light framework providing message passing and cooperative multitasking. The system is actively distributed, enforces the separation between different processing tiers by using different naming domains, and glues them together by dedicated brokers. It provides a powerful Finite State Machine framework to describe custom processing models in a simple regular language. This paper describes this new control system, currently in use at SLAC and Padova on ~450 CPUs organized in 12 farms.
Transparent Persistence with Java Data Objects
Venue: arXiv cs.DB 2003
Year: 2003

Flexible and performant Persistency Service is a necessary component of any HEP Software Framework. The building of a modular, non-intrusive and performant persistency component have been shown to be very difficult task. In the past, it was very often necessary to sacrifice modularity to achieve acceptable performance. This resulted in the strong dependency of the overall Frameworks on their Persistency subsystems. Recent development in software technology has made possible to build a Persistency Service which can be transparently used from other Frameworks. Such Service doesn't force a strong architectural constraints on the overall Framework Architecture, while satisfying high performance requirements. Java Data Object standard (JDO) has been already implemented for almost all major databases. It provides truly transparent persistency for any Java object (both internal and external). Objects in other languages can be handled via transparent proxies. Being only a thin layer on top of a used database, JDO doesn't introduce any significant performance degradation. Also Aspect-Oriented Programming (AOP) makes possible to treat persistency as an orthogonal Aspect of the Application Framework, without polluting it with persistence-specific concepts. All these techniques have been developed primarily (or only) for the Java environment. It is, however, possible to interface them transparently to Frameworks built in other languages, like for example C++. Fully functional prototypes of flexible and non-intrusive persistency modules have been build for several other packages, as for example FreeHEP AIDA and LCG Pool AttributeSet (package Indicium).