title: Cryptanalysis of HFE

abstract: I transform the trapdoor problem of HFE into a linear algebra problem.


title: A mathematical definition of "simplify"

abstract:
  Even though every mathematician knows intuitively what it means to "simplify"
a mathematical expression, there is still no universally accepted rigorous
mathematical definition of "simplify". In this paper, we shall give a simple
and plausible definition of "simplify" in terms of the computational complexity
of integer functions. We shall also use this definition to show that there is
no deterministic and exact algorithm which can compute the permanent of an $n
\times n$ matrix in $o(2^n)$ time.


title: Using Dynamic Simulation in the Development of Construction Machinery

abstract:
  As in the car industry for quite some time, dynamic simulation of complete
vehicles is being practiced more and more in the development of off-road
machinery. However, specific questions arise due not only to company structure
and size, but especially to the type of product. Tightly coupled, non-linear
subsystems of different domains make prediction and optimisation of the
complete system's dynamic behaviour a challenge. Furthermore, the demand for
versatile machines leads to sometimes contradictory target requirements and can
turn the design process into a hunt for the least painful compromise. This can
be avoided by profound system knowledge, assisted by simulation-driven product
development. This paper gives an overview of joint research into this issue by
Volvo Wheel Loaders and Linkoping University on that matter, lists the results
of a related literature review and introduces the term "operateability". Rather
than giving detailed answers, the problem space for ongoing and future research
is examined and possible solutions are sketched.


title: Power Law Distributions in Class Relationships

abstract:
  Power law distributions have been found in many natural and social phenomena,
and more recently in the source code and run-time characteristics of
Object-Oriented (OO) systems. A power law implies that small values are
extremely common, whereas large values are extremely rare. In this paper, we
identify twelve new power laws relating to the static graph structures of Java
programs. The graph structures analyzed represented different forms of OO
coupling, namely, inheritance, aggregation, interface, parameter type and
return type. Identification of these new laws provide the basis for predicting
likely features of classes in future developments. The research in this paper
ties together work in object-based coupling and World Wide Web structures.


title: The Evolution of the Computerized Database

abstract:
  Databases, collections of related data, are as old as the written word. A
database can be anything from a homemaker's metal recipe file to a
sophisticated data warehouse. Yet today, when we think of a database we
invariably think of computerized data and their DBMSs (database management
systems). How did we go from organizing our data in a simple metal filing box
or cabinet to storing our data in a sophisticated computerized database? How
did the computerized database evolve?
  This paper defines what we mean by a database. It traces the evolution of the
database, from its start as a non-computerized set of related data, to the, now
standard, computerized RDBMS (relational database management system). Early
computerized storage methods are reviewed including both the ISAM (Indexed
Sequential Access Method) and VSAM (Virtual Storage Access Method) storage
methods. Early database models are explored including the network and
hierarchical database models. Eventually, the relational, object-relational and
object-oriented databases models are discussed. An appendix of diagrams,
including hierarchical occurrence tree, network schema, ER (entity
relationship) and UML (unified modeling language) diagrams, is included to
support the text.
  This paper concludes with an exploration of current and future trends in DBMS
development. It discusses the factors affecting these trends. It delves into
the relationship between DBMSs and the increasingly popular object-oriented
development methodologies. Finally, it speculates on the future of the DBMS.


title:
Periodicity and Unbordered Words: A Proof of the Extended Duval
  Conjecture

abstract:
  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.


title: Bounded LTL Model Checking with Stable Models

abstract:
  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.


title: Factorization of Language Models through Backing-Off Lattices

abstract:
  Factorization of statistical language models is the task that we resolve the
most discriminative model into factored models and determine a new model by
combining them so as to provide better estimate. Most of previous works mainly
focus on factorizing models of sequential events, each of which allows only one
factorization manner. To enable parallel factorization, which allows a model
event to be resolved in more than one ways at the same time, we propose a
general framework, where we adopt a backing-off lattice to reflect parallel
factorizations and to define the paths along which a model is resolved into
factored models, we use a mixture model to combine parallel paths in the
lattice, and generalize Katz's backing-off method to integrate all the mixture
models got by traversing the entire lattice. Based on this framework, we
formulate two types of model factorizations that are used in natural language
modeling.


title:
Untraceable Email Cluster Bombs: On Agent-Based Distributed Denial of
  Service

abstract:
  We uncover a vulnerability that allows for an attacker to perform an
email-based attack on selected victims, using only standard scripts and agents.
What differentiates the attack we describe from other, already known forms of
distributed denial of service (DDoS) attacks is that an attacker does not need
to infiltrate the network in any manner -- as is normally required to launch a
DDoS attack. Thus, we see this type of attack as a poor man's DDoS. Not only is
the attack easy to mount, but it is also almost impossible to trace back to the
perpetrator. Along with descriptions of our attack, we demonstrate its
destructive potential with (limited and contained) experimental results. We
illustrate the potential impact of our attack by describing how an attacker can
disable an email account by flooding its inbox; block competition during
on-line auctions; harm competitors with an on-line presence; disrupt phone
service to a given victim; cheat in SMS-based games; disconnect mobile
corporate leaders from their networks; and disrupt electronic elections.
Finally, we propose a set of countermeasures that are light-weight, do not
require modifications to the infrastructure, and can be deployed in a gradual
manner.


title:
Modeling of aerodynamic Space-to-Surface flight with optimal trajectory
  for targeting

abstract:
  Modeling has been created for a Space-to-Surface system defined for an
optimal trajectory for targeting in terminal phase. The modeling includes
models for simulation atmosphere, speed of sound, aerodynamic flight and
navigation by an infrared system. The modeling simulation includes statistical
analysis of the modeling results.


title: Updating beliefs with incomplete observations

abstract:
  Currently, there is renewed interest in the problem, raised by Shafer in
1985, of updating probabilities when observations are incomplete. This is a
fundamental problem in general, and of particular interest for Bayesian
networks. Recently, Grunwald and Halpern have shown that commonly used updating
strategies fail in this case, except under very special assumptions. In this
paper we propose a new method for updating probabilities with incomplete
observations. Our approach is deliberately conservative: we make no assumptions
about the so-called incompleteness mechanism that associates complete with
incomplete observations. We model our ignorance about this mechanism by a
vacuous lower prevision, a tool from the theory of imprecise probabilities, and
we use only coherence arguments to turn prior into posterior probabilities. In
general, this new approach to updating produces lower and upper posterior
probabilities and expectations, as well as partially determinate decisions.
This is a logical consequence of the existing ignorance about the
incompleteness mechanism. We apply the new approach to the problem of
classification of new evidence in probabilistic expert systems, where it leads
to a new, so-called conservative updating rule. In the special case of Bayesian
networks constructed using expert knowledge, we provide an exact algorithm for
classification based on our updating rule, which has linear-time complexity for
a class of networks wider than polytrees. This result is then extended to the
more general framework of credal networks, where computations are often much
harder than with Bayesian nets. Using an example, we show that our rule appears
to provide a solid basis for reliable updating with incomplete observations,
when no strong assumptions about the incompleteness mechanism are justified.


title:
Semiclassical Quantum Computation Solutions to the Count to Infinity
  Problem: A Brief Discussion

abstract:
  In this paper we briefly define distance vector routing algorithms, their
advantages and possible drawbacks. On these possible drawbacks, currently
widely used methods split horizon and poisoned reverse are defined and
compared. The count to infinity problem is specified and it is classified to be
a halting problem and a proposition stating that entangled states used in
quantum computation can be used to handle this problem is examined. Several
solutions to this problem by using entangled states are proposed and a very
brief introduction to entangled states is presented.


title: Applications of Intuitionistic Logic in Answer Set Programming

abstract:
  We present some applications of intermediate logics in the field of Answer
Set Programming (ASP). A brief, but comprehensive introduction to the answer
set semantics, intuitionistic and other intermediate logics is given. Some
equivalence notions and their applications are discussed. Some results on
intermediate logics are shown, and applied later to prove properties of answer
sets. A characterization of answer sets for logic programs with nested
expressions is provided in terms of intuitionistic provability, generalizing a
recent result given by Pearce.
  It is known that the answer set semantics for logic programs with nested
expressions may select non-minimal models. Minimal models can be very important
in some applications, therefore we studied them; in particular we obtain a
characterization, in terms of intuitionistic logic, of answer sets which are
also minimal models. We show that the logic G3 characterizes the notion of
strong equivalence between programs under the semantic induced by these models.
Finally we discuss possible applications and consequences of our results. They
clearly state interesting links between ASP and intermediate logics, which
might bring research in these two areas together.


title: CASTOR status and evolution

abstract:
  In January 1999, CERN began to develop CASTOR ("CERN Advanced STORage
manager"). This Hierarchical Storage Manager targetted at HEP applications has
been in full production at CERN since May 2001. It now contains more than two
Petabyte of data in roughly 9 million files. In 2002, 350 Terabytes of data
were stored for COMPASS at 45 MB/s and a Data Challenge was run for ALICE in
preparation for the LHC startup in 2007 and sustained a data transfer to tape
of 300 MB/s for one week (180 TB). The major functionality improvements were
the support for files larger than 2 GB (in collaboration with IN2P3) and the
development of Grid interfaces to CASTOR: GridFTP and SRM ("Storage Resource
Manager"). An ongoing effort is taking place to copy the existing data from
obsolete media like 9940 A to better cost effective offerings. CASTOR has also
been deployed at several HEP sites with little effort. In 2003, we plan to
continue working on Grid interfaces and to improve performance not only for
Central Data Recording but also for Data Analysis applications where thousands
of processes possibly access the same hot data. This could imply the selection
of another filesystem or the use of replication (hardware or software).


title: 2D Electrophoresis Gel Image and Diagnosis of a Disease

abstract:
  The process of diagnosing a disease from the 2D gel electrophoresis image is
a challenging problem. This is due to technical difficulties of generating
reproducible images with a normalized form and the effect of negative stain. In
this paper, we will discuss a new concept of interpreting the 2D images and
overcoming the aforementioned technical difficulties using mathematical
transformation. The method makes use of 2D gel images of proteins in serums and
we explain a way of representing the images into vectors in order to apply
machine-learning methods, such as the support vector machine.


title: The Athena Data Dictionary and Description Language

abstract:
  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.


title:
Towards automation of computing fabrics using tools from the fabric
  management workpackage of the EU DataGrid project

abstract:
  The EU DataGrid project workpackage 4 has as an objective to provide the
necessary tools for automating the management of medium size to very large
computing fabrics. At the end of the second project year subsystems for
centralized configuration management (presented at LISA'02) and
performance/exception monitoring have been delivered. This will soon be
augmented with a subsystem for node installation and service configuration,
which is based on existing widely used standards where available (e.g. rpm,
kickstart, init.d scripts) and clean interfaces to OS dependent components
(e.g. base installation and service management). The three subsystems together
allow for centralized management of very large computer farms. Finally, a fault
tolerance system is being developed for tying together the above subsystems to
form a complete framework for automated enterprise computing management by
3Q03. All software developed is open source covered by the EU DataGrid project
license agreements. This article describes the architecture behind the designed
fabric management system and the status of the different developments. It also
covers the experience with an existing tool for automated configuration and
installation that have been adapted and used from the beginning to manage the
EU DataGrid testbed, which is now used for LHC data challenges.


title: Sharp Bounds for Bandwidth of Clique Products

abstract:
  The bandwidth of a graph is the labeling of vertices with minimum maximum
edge difference. For many graph families this is NP-complete. A classic result
computes the bandwidth for the hypercube. We generalize this result to give
sharp lower bounds for products of cliques. This problem turns out to be
equivalent to one in communication over multiple channels in which channels can
fail and the information sent over those channels is lost. The goal is to
create an encoding that minimizes the difference between the received and the
original information while having as little redundancy as possible. Berger-Wolf
and Reingold [2] have considered the problem for the equal size cliques (or
equal capacity channels). This paper presents a tight lower bound and an
algorithm for constructing the labeling for the product of any number of
arbitrary size cliques.


title: On the Existence and Convergence Computable Universal Priors

abstract:
  Solomonoff unified Occam's razor and Epicurus' principle of multiple
explanations to one elegant, formal, universal theory of inductive inference,
which initiated the field of algorithmic information theory. His central result
is that the posterior of his universal semimeasure M converges rapidly to the
true sequence generating posterior mu, if the latter is computable. Hence, M is
eligible as a universal predictor in case of unknown mu. We investigate the
existence and convergence of computable universal (semi)measures for a
hierarchy of computability classes: finitely computable, estimable, enumerable,
and approximable. For instance, M is known to be enumerable, but not finitely
computable, and to dominate all enumerable semimeasures. We define seven
classes of (semi)measures based on these four computability concepts. Each
class may or may not contain a (semi)measure which dominates all elements of
another class. The analysis of these 49 cases can be reduced to four basic
cases, two of them being new. The results hold for discrete and continuous
semimeasures. We also investigate more closely the types of convergence,
possibly implied by universality: in difference and in ratio, with probability
1, in mean sum, and for Martin-Loef random sequences. We introduce a
generalized concept of randomness for individual sequences and use it to
exhibit difficulties regarding these issues.


title: Developing Open Data Models for Linguistic Field Data

abstract:
  The UQ Flint Archive houses the field notes and elicitation recordings made
by Elwyn Flint in the 1950's and 1960's during extensive linguistic survey work
across Queensland, Australia.
  The process of digitizing the contents of the UQ Flint Archive provides a
number of interesting challenges in the context of EMELD. Firstly, all of the
linguistic data is for languages which are either endangered or extinct, and as
such forms a valuable ethnographic repository. Secondly, the physical format of
the data is itself in danger of decline, and as such digitization is an
important preservation task in the short to medium term. Thirdly, the adoption
of open standards for the encoding and presentation of text and audio data for
linguistic field data, whilst enabling preservation, represents a new field of
research in itself where best practice has yet to be formalised. Fourthly, the
provision of this linguistic data online as a new data source for future
research introduces concerns of data portability and longevity.
  This paper will outline the origins of the data model, the content creation
components, presentation forms based on the data model, data capture tools and
media conversion components. It will also address some of the larger questions
regarding the digitization and annotation of linguistic field work based on
experience gained through work with the Flint Archive contents.


title: A Monitoring System for the BaBar INFN Computing Cluster

abstract:
  Monitoring large clusters is a challenging problem. It is necessary to
observe a large quantity of devices with a reasonably short delay between
consecutive observations. The set of monitored devices may include PCs, network
switches, tape libraries and other equipments. The monitoring activity should
not impact the performances of the system. In this paper we present PerfMC, a
monitoring system for large clusters. PerfMC is driven by an XML configuration
file, and uses the Simple Network Management Protocol (SNMP) for data
collection. SNMP is a standard protocol implemented by many networked
equipments, so the tool can be used to monitor a wide range of devices. System
administrators can display informations on the status of each device by
connecting to a WEB server embedded in PerfMC. The WEB server can produce
graphs showing the value of different monitored quantities as a function of
time; it can also produce arbitrary XML pages by applying XSL Transformations
to an internal XML representation of the cluster's status. XSL Transformations
may be used to produce HTML pages which can be displayed by ordinary WEB
browsers. PerfMC aims at being relatively easy to configure and operate, and
highly efficient. It is currently being used to monitor the Italian
Reprocessing farm for the BaBar experiment, which is made of about 200 dual-CPU
Linux machines.


title: Goodness-of-fit of the Heston model

abstract:
  An analytical formula for the probability distribution of stock-market
returns, derived from the Heston model assuming a mean-reverting stochastic
volatility, was recently proposed by Dragulescu and Yakovenko in Quantitative
Finance 2002. While replicating their results, we found two significant
weaknesses in their method to pre-process the data, which cast a shadow over
the effective goodness-of-fit of the model. We propose a new method, more truly
capturing the market, and perform a Kolmogorov-Smirnov test and a Chi Square
test on the resulting probability distribution. The results raise some
significant questions for large time lags -- 40 to 250 days -- where the
smoothness of the data does not require such a complex model; nevertheless, we
also provide some statistical evidence in favour of the Heston model for small
time lags -- 1 and 5 days -- compared with the traditional Gaussian model
assuming constant volatility.


title: Configuration Database for BaBar On-line

abstract:
  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.


title: The Persint visualization program for the ATLAS experiment

abstract:
  The Persint program is designed for the three-dimensional representation of
objects and for the interfacing and access to a variety of independent
applications, in a fully interactive way. Facilities are provided for the
spatial navigation and the definition of the visualization properties, in order
to interactively set the viewing and viewed points, and to obtain the desired
perspective. In parallel, applications may be launched through the use of
dedicated interfaces, such as the interactive reconstruction and display of
physics events. Recent developments have focalized on the interfacing to the
XML ATLAS General Detector Description AGDD, making it a widely used tool for
XML developers. The graphics capabilities of this program were exploited in the
context of the ATLAS 2002 Muon Testbeam where it was used as an online event
display, integrated in the online software framework and participating in the
commissioning and debug of the detector system.


title: ATLAS and CMS applications on the WorldGrid testbed

abstract:
  WorldGrid is an intercontinental testbed spanning Europe and the US
integrating architecturally different Grid implementations based on the Globus
toolkit. It has been developed in the context of the DataTAG and iVDGL
projects, and successfully demonstrated during the WorldGrid demos at IST2002
(Copenhagen) and SC2002 (Baltimore). Two HEP experiments, ATLAS and CMS,
successful exploited the WorldGrid testbed for executing jobs simulating the
response of their detectors to physics eve nts produced by real collisions
expected at the LHC accelerator starting from 2007. This data intensive
activity has been run since many years on local dedicated computing farms
consisting of hundreds of nodes and Terabytes of disk and tape storage. Within
the WorldGrid testbed, for the first time HEP simulation jobs were submitted
and run indifferently on US and European resources, despite of their underlying
different Grid implementations, and produced data which could be retrieved and
further analysed on the submitting machine, or simply stored on the remote
resources and registered on a Replica Catalogue which made them available to
the Grid for further processing. In this contribution we describe the job
submission from Europe for both ATLAS and CMS applications, performed through
the GENIUS portal operating on top of an EDG User Interface submitting to an
EDG Resource Broker, pointing out the chosen interoperability solutions which
made US and European resources equivalent from the applications point of view,
the data management in the WorldGrid environment, and the CMS specific
production tools which were interfaced to the GENIUS portal.


title: EU DataGRID testbed management and support at CERN

abstract:
  In this paper we report on the first two years of running the CERN testbed
site for the EU DataGRID project. The site consists of about 120 dual-processor
PCs distributed over several testbeds used for different purposes: software
development, system integration, and application tests. Activities at the site
included test productions of MonteCarlo data for LHC experiments, tutorials and
demonstrations of GRID technologies, and support for individual users analysis.
This paper focuses on node installation and configuration techniques, service
management, user support in a gridified environment, and includes
considerations on scalability and security issues and comparisons with
"traditional" production systems, as seen from the administrator point of view.


title:
Performance comparison between iSCSI and other hardware and software
  solutions

abstract:
  We report on our investigations on some technologies that can be used to
build disk servers and networks of disk servers using commodity hardware and
software solutions. It focuses on the performance that can be achieved by these
systems and gives measured figures for different configurations.
  It is divided into two parts : iSCSI and other technologies and hardware and
software RAID solutions.
  The first part studies different technologies that can be used by clients to
access disk servers using a gigabit ethernet network. It covers block access
technologies (iSCSI, hyperSCSI, ENBD). Experimental figures are given for
different numbers of clients and servers.
  The second part compares a system based on 3ware hardware RAID controllers, a
system using linux software RAID and IDE cards and a system mixing both
hardware RAID and software RAID. Performance measurements for reading and
writing are given for different RAID levels.


title: A Secure Infrastructure For System Console and Reset Access

abstract:
  During the last years large farms have been built using commodity hardware.
This hardware lacks components for remote and automated administration.
Products that can be retrofitted to these systems are either costly or
inherently insecure. We present a system based on serial ports and simple
machine controlled relays. We report on experience gained by setting up a
50-machine test environment as well as current work in progress in the area.


title: DIAMOnDS - DIstributed Agents for MObile & Dynamic Services

abstract:
  Distributed Services Architecture with support for mobile agents between
services, offer significantly improved communication and computational
flexibility. The uses of agents allow execution of complex operations that
involve large amounts of data to be processed effectively using distributed
resources. The prototype system Distributed Agents for Mobile and Dynamic
Services (DIAMOnDS), allows a service to send agents on its behalf, to other
services, to perform data manipulation and processing. Agents have been
implemented as mobile services that are discovered using the Jini Lookup
mechanism and used by other services for task management and communication.
Agents provide proxies for interaction with other services as well as specific
GUI to monitor and control the agent activity. Thus agents acting on behalf of
one service cooperate with other services to carry out a job, providing
inter-operation of loosely coupled services in a semi-autonomous way. Remote
file system access functionality has been incorporated by the agent framework
and allows services to dynamically share and browse the file system resources
of hosts, running the services. Generic database access functionality has been
implemented in the mobile agent framework that allows performing complex data
mining and processing operations efficiently in distributed system. A basic
data searching agent is also implemented that performs a query based search in
a file system. The testing of the framework was carried out on WAN by moving
Connectivity Test agents between AgentStations in CERN, Switzerland and NUST,
Pakistan.


title:
McRunjob: A High Energy Physics Workflow Planner for Grid Production
  Processing

abstract:
  McRunjob is a powerful grid workflow manager used to manage the generation of
large numbers of production processing jobs in High Energy Physics. In use at
both the DZero and CMS experiments, McRunjob has been used to manage large
Monte Carlo production processing since 1999 and is being extended to uses in
regular production processing for analysis and reconstruction. Described at
CHEP 2001, McRunjob converts core metadata into jobs submittable in a variety
of environments. The powerful core metadata description language includes
methods for converting the metadata into persistent forms, job descriptions,
multi-step workflows, and data provenance information. The language features
allow for structure in the metadata by including full expressions, namespaces,
functional dependencies, site specific parameters in a grid environment, and
ontological definitions. It also has simple control structures for
parallelization of large jobs. McRunjob features a modular design which allows
for easy expansion to new job description languages or new application level
tasks.


title: The use of Ethernet in the DataFlow of the ATLAS Trigger & DAQ

abstract:
  The article analyzes a proposed network topology for the ATLAS DAQ DataFlow,
and identifies the Ethernet features required for a proper operation of the
network: MAC address table size, switch performance in terms of throughput and
latency, the use of Flow Control, Virtual LANs and Quality of Service. We
investigate these features on some Ethernet switches, and conclude on their
usefulness for the ATLAS DataFlow network.


title: A Generic Multi-node State Monitoring Subsystem

abstract:
  The BaBar online data acquisition (DAQ) system includes approximately fifty
Unix systems that collectively implement the level-three trigger. These systems
all run the same code. Each of these systems has its own state, and this state
is expected to change in response to changes in the overall DAQ system. A
specialized subsystem has been developed to initiate processing on this
collection of systems, and to monitor them both for error conditions and to
ensure that they all follow the same state trajectory within a specifiable
period of time. This subsystem receives start commands from the main DAQ run
control system, and reports major coherent state changes, as well as error
conditions, back to the run control system. This state monitoring subsystem has
the novel feature that it does not know anything about the state machines that
it is monitoring, and hence does not introduce any fundamentally new state
machine into the overall system. This feature makes it trivially applicable to
other multi-node subsystems. Indeed it has already found a second application
beyond the level-three trigger, within the BaBar experiment.


title: The CMS Integration Grid Testbed

abstract:
  The CMS Integration Grid Testbed (IGT) comprises USCMS Tier-1 and Tier-2
hardware at the following sites: the California Institute of Technology, Fermi
National Accelerator Laboratory, the University of California at San Diego, and
the University of Florida at Gainesville. The IGT runs jobs using the Globus
Toolkit with a DAGMan and Condor-G front end. The virtual organization (VO) is
managed using VO management scripts from the European Data Grid (EDG). Gridwide
monitoring is accomplished using local tools such as Ganglia interfaced into
the Globus Metadata Directory Service (MDS) and the agent based Mona Lisa.
Domain specific software is packaged and installed using the Distrib ution
After Release (DAR) tool of CMS, while middleware under the auspices of the
Virtual Data Toolkit (VDT) is distributed using Pacman. During a continuo us
two month span in Fall of 2002, over 1 million official CMS GEANT based Monte
Carlo events were generated and returned to CERN for analysis while being
demonstrated at SC2002. In this paper, we describe the process that led to one
of the world's first continuously available, functioning grids.


title: Clarens Client and Server Applications

abstract:
  Several applications have been implemented with access via the Clarens web
service infrastructure, including virtual organization management, JetMET
physics data analysis using relational databases, and Storage Resource Broker
(SRB) access. This functionality is accessible transparently from Python
scripts, the Root analysis framework and from Java applications and browser
applets.


title: The Clarens web services architecture

abstract:
  Clarens is a uniquely flexible web services infrastructure providing a
unified access protocol to a diverse set of functions useful to the HEP
community. It uses the standard HTTP protocol combined with application layer,
certificate based authentication to provide single sign-on to individuals,
organizations and hosts, with fine-grained access control to services, files
and virtual organization (VO) management. This contribution describes the
server functionality, while client applications are described in a subsequent
talk.


title: R-GMA: First results after deployment

abstract:
  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.


title: Managing Dynamic User Communities in a Grid of Autonomous Resources

abstract:
  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.


title: The Virtual Monte Carlo

abstract:
  The concept of Virtual Monte Carlo (VMC) has been developed by the ALICE
Software Project to allow different Monte Carlo simulation programs to run
without changing the user code, such as the geometry definition, the detector
response simulation or input and output formats. Recently, the VMC classes have
been integrated into the ROOT framework, and the other relevant packages have
been separated from the AliRoot framework and can be used individually by any
other HEP project. The general concept of the VMC and its set of base classes
provided in ROOT will be presented. Existing implementations for Geant3, Geant4
and FLUKA and simple examples of usage will be described.


title:
Experience with the Open Source based implementation for ATLAS
  Conditions Data Management System

abstract:
  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.


title:
The first deployment of workload management services on the EU DataGrid
  Testbed: feedback on design and implementation

abstract:
  Application users have now been experiencing for about a year with the
standardized resource brokering services provided by the 'workload management'
package of the EU DataGrid project (WP1). Understanding, shaping and pushing
the limits of the system has provided valuable feedback on both its design and
implementation. A digest of the lessons, and "better practices", that were
learned, and that were applied towards the second major release of the
software, is given.


title: The new BaBar Data Reconstruction Control System

abstract:
  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.


title: Virtual Data in CMS Production

abstract:
  Initial applications of the GriPhyN Chimera Virtual Data System have been
performed within the context of CMS Production of Monte Carlo Simulated Data.
The GriPhyN Chimera system consists of four primary components: 1) a Virtual
Data Language, which is used to describe virtual data products, 2) a Virtual
Data Catalog, which is used to store virtual data entries, 3) an Abstract
Planner, which resolves all dependencies of a particular virtual data product
and forms a location and existence independent plan, 4) a Concrete Planner,
which maps an abstract, logical plan onto concrete, physical grid resources
accounting for staging in/out files and publishing results to a replica
location service. A CMS Workflow Planner, MCRunJob, is used to generate virtual
data products using the Virtual Data Language. Subsequently, a prototype
workflow manager, known as WorkRunner, is used to schedule the instantiation of
virtual data products across a grid.


title:
On multiple connectedness of regions visible due to multiple diffuse
  reflections

abstract:
  It is known that the region $V(s)$ of a simple polygon $P$, directly visible
(illuminable) from an internal point $s$, is simply connected. Aronov et al.
\cite{addpp981} established that the region $V_1(s)$ of a simple polygon
visible from an internal point $s$ due to at most one diffuse reflection on the
boundary of the polygon $P$, is also simply connected. In this paper we
establish that the region $V_2(s)$, visible from $s$ due to at most two diffuse
reflections may be multiply connected; we demonstrate the construction of an
$n$-sided simple polygon with a point $s$ inside it so that and the region of
$P$ visible from $s$ after at most two diffuse reflections is multiple
connected.


title:
Grid Data Management in Action: Experience in Running and Supporting
  Data Management Services in the EU DataGrid Project

abstract:
  In the first phase of the EU DataGrid (EDG) project, a Data Management System
has been implemented and provided for deployment. The components of the current
EDG Testbed are: a prototype of a Replica Manager Service built around the
basic services provided by Globus, a centralised Replica Catalogue to store
information about physical locations of files, and the Grid Data Mirroring
Package (GDMP) that is widely used in various HEP collaborations in Europe and
the US for data mirroring. During this year these services have been refined
and made more robust so that they are fit to be used in a pre-production
environment. Application users have been using this first release of the Data
Management Services for more than a year. In the paper we present the
components and their interaction, our implementation and experience as well as
the feedback received from our user communities. We have resolved not only
issues regarding integration with other EDG service components but also many of
the interoperability issues with components of our partner projects in Europe
and the U.S. The paper concludes with the basic lessons learned during this
operation. These conclusions provide the motivation for the architecture of the
next generation of Data Management Services that will be deployed in EDG during
2003.


title: GraXML - Modular Geometric Modeler

abstract:
  Many entities managed by HEP Software Frameworks represent spatial
(3-dimensional) real objects. Effective definition, manipulation and
visualization of such objects is an indispensable functionality.
  GraXML is a modular Geometric Modeling toolkit capable of processing
geometric data of various kinds (detector geometry, event geometry) from
different sources and delivering them in ways suitable for further use.
Geometric data are first modeled in one of the Generic Models. Those Models are
then used to populate powerful Geometric Model based on the Java3D technology.
While Java3D has been originally created just to provide visualization of 3D
objects, its light weight and high functionality allow an effective reuse as a
general geometric component. This is possible also thanks to a large overlap
between graphical and general geometric functionality and modular design of
Java3D itself. Its graphical functionalities also allow a natural visualization
of all manipulated elements.
  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++.
  The GraXML toolkit has been tested with data from several sources, as for
example ATLAS and ALICE detector description and ATLAS event data. Prototypes
for other sources, like Geometry Description Markup Language (GDML) exist too
and interface to any other source is easy to add.


title: Transparent Persistence with Java Data Objects

abstract:
  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).


title:
SCRAM: Software configuration and management for the LHC Computing Grid
  project

abstract:
  Recently SCRAM (Software Configuration And Management) has been adopted by
the applications area of the LHC computing grid project as baseline
configuration management and build support infrastructure tool.
  SCRAM is a software engineering tool, that supports the configuration
management and management processes for software development. It resolves the
issues of configuration definition, assembly break-down, build, project
organization, run-time environment, installation, distribution, deployment, and
source code distribution. It was designed with a focus on supporting a
distributed, multi-project development work-model.
  We will describe the underlying technology, and the solutions SCRAM offers to
the above software engineering processes, while taking a users view of the
system under configuration management.


title:
Computing sharp and scalable bounds on errors in approximate zeros of
  univariate polynomials

abstract:
  There are several numerical methods for computing approximate zeros of a
given univariate polynomial. In this paper, we develop a simple and novel
method for determining sharp upper bounds on errors in approximate zeros of a
given polynomial using Rouche's theorem from complex analysis. We compute the
error bounds using non-linear optimization. Our bounds are scalable in the
sense that we compute sharper error bounds for better approximations of zeros.
We use high precision computations using the LEDA/real floating-point filter
for computing our bounds robustly.


title: Modelling Biochemical Operations on RNA Secondary Structures

abstract:
  In this paper we model several simple biochemical operations on RNA molecules
that modify their secondary structure by means of a suitable variation of
Gro\ss e-Rhode's Algebra Transformation Systems.


title: Minimum Model Semantics for Logic Programs with Negation-as-Failure

abstract:
  We give a purely model-theoretic characterization of the semantics of logic
programs with negation-as-failure allowed in clause bodies. In our semantics
the meaning of a program is, as in the classical case, the unique minimum model
in a program-independent ordering. We use an expanded truth domain that has an
uncountable linearly ordered set of truth values between False (the minimum
element) and True (the maximum), with a Zero element in the middle. The truth
values below Zero are ordered like the countable ordinals. The values above
Zero have exactly the reverse order. Negation is interpreted as reflection
about Zero followed by a step towards Zero; the only truth value that remains
unaffected by negation is Zero. We show that every program has a unique minimum
model M_P, and that this model can be constructed with a T_P iteration which
proceeds through the countable ordinals. Furthermore, we demonstrate that M_P
can also be obtained through a model intersection construction which
generalizes the well-known model intersection theorem for classical logic
programming. Finally, we show that by collapsing the true and false values of
the infinite-valued model M_P to (the classical) True and False, we obtain a
three-valued model identical to the well-founded one.


title: A monitoring tool for a GRID operation center

abstract:
  WorldGRID is an intercontinental testbed spanning Europe and the US
integrating architecturally different Grid implementations based on the Globus
toolkit. The WorldGRID testbed has been successfully demonstrated during the
WorldGRID demos at SuperComputing 2002 (Baltimore) and IST2002 (Copenhagen)
where real HEP application jobs were transparently submitted from US and Europe
using "native" mechanisms and run where resources were available, independently
of their location. To monitor the behavior and performance of such testbed and
spot problems as soon as they arise, DataTAG has developed the EDT-Monitor tool
based on the Nagios package that allows for Virtual Organization centric views
of the Grid through dynamic geographical maps. The tool has been used to spot
several problems during the WorldGRID operations, such as malfunctioning
Resource Brokers or Information Servers, sites not correctly configured, job
dispatching problems, etc. In this paper we give an overview of the package,
its features and scalability solutions and we report on the experience acquired
and the benefit that a GRID operation center would gain from such a tool.


title: Relational databases for data management in PHENIX

abstract:
  PHENIX is one of the two large experiments at the Relativistic Heavy Ion
Collider (RHIC) at Brookhaven National Laboratory (BNL) and archives roughly
100TB of experimental data per year. In addition, large volumes of simulated
data are produced at multiple off-site computing centers. For any file catalog
to play a central role in data management it has to face problems associated
with the need for distributed access and updates. To be used effectively by the
hundreds of PHENIX collaborators in 12 countries the catalog must satisfy the
following requirements: 1) contain up-to-date data, 2) provide fast and
reliable access to the data, 3) have write permissions for the sites that store
portions of data. We present an analysis of several available Relational
Database Management Systems (RDBMS) to support a catalog meeting the above
requirements and discuss the PHENIX experience with building and using the
distributed file catalog.


title:
On the Verge of One Petabyte - the Story Behind the BaBar Database
  System

abstract:
  The BaBar database has pioneered the use of a commercial ODBMS within the HEP
community. The unique object-oriented architecture of Objectivity/DB has made
it possible to manage over 700 terabytes of production data generated since
May'99, making the BaBar database the world's largest known database. The
ongoing development includes new features, addressing the ever-increasing
luminosity of the detector as well as other changing physics requirements.
Significant efforts are focused on reducing space requirements and operational
costs. The paper discusses our experience with developing a large scale
database system, emphasizing universal aspects which may be applied to any
large scale system, independently of underlying technology used.


title:
Visualization for Periodic Population Movement between Distinct
  Localities

abstract:
  We present a new visualization method to summarize and present periodic
population movement between distinct locations, such as floors, buildings,
cities, or the like. In the specific case of this paper, we have chosen to
focus on student movement between college dormitories on the Columbia
University campus. The visual information is presented to the information
analyst in the form of an interactive geographical map, in which specific
temporal periods as well as individual buildings can be singled out for
detailed data exploration. The navigational interface has been designed to
specifically meet a geographical setting.


title: Techniques for effective vocabulary selection

abstract:
  The vocabulary of a continuous speech recognition (CSR) system is a
significant factor in determining its performance. In this paper, we present
three principled approaches to select the target vocabulary for a particular
domain by trading off between the target out-of-vocabulary (OOV) rate and
vocabulary size. We evaluate these approaches against an ad-hoc baseline
strategy. Results are presented in the form of OOV rate graphs plotted against
increasing vocabulary size for each technique.


title: The Redesigned BaBar Event Store: Believe the Hype

abstract:
  As the BaBar experiment progresses, it produces new and unforeseen
requirements and increasing demands on capacity and feature base. The current
system is being utilized well beyond its original design specifications, and
has scaled appropriately, maintaining data consistency and durability. The
persistent event storage system has remained largely unchanged since the
initial implementation, and thus includes many design features which have
become performance bottlenecks. Programming interfaces were designed before
sufficient usage information became available. Performance and efficiency were
traded off for added flexibility to cope with future demands. With significant
experience in managing actual production data under our belt, we are now in a
position to recraft the system to better suit current needs. The Event Store
redesign is intended to eliminate redundant features while adding new ones,
increase overall performance, and contain the physical storage cost of the
world's largest database.


title: Monitoring Systems and Services

abstract:
  The DESY Computer Center is the home of O(1000) computers supplying a wide
range of different services Monitoring such a large installation is a
challenge. After a long time running a SNMP based commercial Network Management
System, the evaluation of a new System was started. There are a lot of
different commercial and freeware products on the market, but none of them
fully satisfied all our requirements. After re-valuating our original
requirements we selected NAGIOS as our monitoring and alarming tool. After a
successful test we are in production since autumn 2002 and are extending the
service to fully support a distributed monitoring and alarming.


title: Permutation Generation: Two New Permutation Algorithms

abstract:
  Two completely new algorithms for generating permutations, shift-cursor
algorithm and level algorithm, and their efficient implementations are
presented in this paper. One implementation of the shift cursor algorithm gives
an optimal solution of the permutation generation problem, and one
implementation of the level algorithm can be used to generate random
permutations.


title: BdbServer++: A User Driven Data Location and Retrieval Tool

abstract:
  The adoption of Grid technology has the potential to greatly aid the BaBar
experiment. BdbServer was originally designed to extract copies of data from
the Objectivity/DB database at SLAC and IN2P3. With data now stored in multiple
locations in a variety of data formats, we are enhancing this tool. This will
enable users to extract selected deep copies of event collections and ship them
to the requested site using the facilities offered by the existing Grid
infrastructure. By building on the work done by various groups in BaBar, and
the European DataGrid, we have successfully expanded the capabilities of the
BdbServer software. This should provide a framework for future work in data
distribution.


title: HEP Applications Evaluation of the EDG Testbed and Middleware

abstract:
  Workpackage 8 of the European Datagrid project was formed in January 2001
with representatives from the four LHC experiments, and with experiment
independent people from five of the six main EDG partners. In September 2002
WP8 was strengthened by the addition of effort from BaBar and D0. The original
mandate of WP8 was, following the definition of short- and long-term
requirements, to port experiment software to the EDG middleware and testbed
environment. A major additional activity has been testing the basic
functionality and performance of this environment. This paper reviews
experiences and evaluations in the areas of job submission, data management,
mass storage handling, information systems and monitoring. It also comments on
the problems of remote debugging, the portability of code, and scaling problems
with increasing numbers of jobs, sites and nodes. Reference is made to the
pioneeering work of Atlas and CMS in integrating the use of the EDG Testbed
into their data challenges. A forward look is made to essential software
developments within EDG and to the necessary cooperation between EDG and LCG
for the LCG prototype due in mid 2003.


title: An Abstract Programming System

abstract:
  The system PL permits the translation of abstract proofs of program
correctness into programs in a variety of programming languages. A programming
language satisfying certain axioms may be the target of such a translation. The
system PL also permits the construction and proof of correctness of programs in
an abstract programming language, and permits the translation of these programs
into correct programs in a variety of languages. The abstract programming
language has an imperative style of programming with assignment statements and
side-effects, to allow the efficient generation of code. The abstract programs
may be written by humans and then translated, avoiding the need to write the
same program repeatedly in different languages or even the same language. This
system uses classical logic, is conceptually simple, and permits reasoning
about nonterminating programs using Scott-Strachey style denotational
semantics.


title: A Software Data Transport Framework for Trigger Applications on Clusters

abstract:
  In the future ALICE heavy ion experiment at CERN's Large Hadron Collider
input data rates of up to 25 GB/s have to be handled by the High Level Trigger
(HLT) system, which has to scale them down to at most 1.25 GB/s before being
written to permanent storage. The HLT system that is being designed to cope
with these data rates consists of a large PC cluster, up to the order of a 1000
nodes, connected by a fast network. For the software that will run on these
nodes a flexible data transport and distribution software framework has been
developed. This framework consists of a set of separate components, that can be
connected via a common interface, allowing to construct different
configurations for the HLT, that are even changeable at runtime. To ensure a
fault-tolerant operation of the HLT, the framework includes a basic fail-over
mechanism that will be further expanded in the future, utilizing the runtime
reconnection feature of the framework's component interface. First performance
tests show very promising results for the software, indicating that it can
achieve an event rate for the data transport sufficiently high to satisfy
ALICE's requirements.


title:
Grid-based access control for Unix environments, Filesystems and Web
  Sites

abstract:
  The EU DataGrid has deployed a grid testbed at approximately 20 sites across
Europe, with several hundred registered users. This paper describes
authorisation systems produced by GridPP and currently used on the EU DataGrid
Testbed, including local Unix pool accounts and fine-grained access control
with Access Control Lists and Grid-aware filesystems, fileservers and web
developement environments.


title: The FRED Event Display: an Extensible HepRep Client for GLAST

abstract:
  A new graphics client prototype for the HepRep protocol is presented. Based
on modern toolkits and high level languages (C++ and Ruby), Fred is an
experiment to test applicability of scripting facilities to the high energy
physics event display domain. Its flexible structure, extensibility and the use
of the HepRep protocol are key features for its use in the astroparticle
experiment GLAST.


title:
Length-Based Attacks for Certain Group Based Encryption Rewriting
  Systems

abstract:
  In this note, we describe a probabilistic attack on public key cryptosystems
based on the word/conjugacy problems for finitely presented groups of the type
proposed recently by Anshel, Anshel and Goldfeld. In such a scheme, one makes
use of the property that in the given group the word problem has a polynomial
time solution, while the conjugacy problem has no known polynomial solution. An
example is the braid group from topology in which the word problem is solvable
in polynomial time while the only known solutions to the conjugacy problem are
exponential. The attack in this paper is based on having a canonical
representative of each string relative to which a length function may be
computed. Hence the term length attack. Such canonical representatives are
known to exist for the braid group.


title: Multi-valued Connectives for Fuzzy Sets

abstract:
  We present a procedure for the construction of multi-valued t-norms and
t-conorms. Our procedure makes use of a pair of single-valued t-norms and the
respective dual t-conorms and produces interval-valued t-norms and t-conorms.
In this manner we combine desirable characteristics of different t-norms and
t-conorms; if we use the t-norm min and t-conorm max, then the resulting
structure is a superlattice, i.e. the multivalued analog of a lattice.


title: A ROOT/IO Based Software Framework for CMS

abstract:
  The implementation of persistency in the Compact Muon Solenoid (CMS) Software
Framework uses the core I/O functionality of ROOT. We will discuss the current
ROOT/IO implementation, its evolution from the prior Objectivity/DB
implementation, and the plans and ongoing work for the conversion to "POOL",
provided by the LHC Computing Grid (LCG) persistency project.


title:
A Transformational Decision Procedure for Non-Clausal Propositional
  Formulas

abstract:
  A decision procedure for detecting valid propositional formulas is presented.
It is based on the Davis-Putnam method and deals with propositional formulas
that are initially converted to negational normal form. This procedure splits
variables but, in contrast to other decision procedures based on the
Davis-Putnam method, it does not branch. Instead, this procedure iteratively
makes validity-preserving transformations of fragments of the formula. The
transformations involve only a minimal formula part containing occurrences of
the selected variable. Selection of the best variable for splitting is crucial
in this decision procedure - it may shorten the decision process dramatically.
A variable whose splitting leads to a minimal size of the transformed formula
is selected. Also, the decision procedure performs plenty of optimizations
based on calculation of delta-sets. Some optimizations lead to removing
fragments of the formula. Others detect variables for which a single truth
value assignment is sufficient. The latest information about this research can
be found at http://www.sakharov.net/valid.html


title: Sequence Prediction based on Monotone Complexity

abstract:
  This paper studies sequence prediction based on the monotone Kolmogorov
complexity Km=-log m, i.e. based on universal deterministic/one-part MDL. m is
extremely close to Solomonoff's prior M, the latter being an excellent
predictor in deterministic as well as probabilistic environments, where
performance is measured in terms of convergence of posteriors or losses.
Despite this closeness to M, it is difficult to assess the prediction quality
of m, since little is known about the closeness of their posteriors, which are
the important quantities for prediction. We show that for deterministic
computable environments, the "posterior" and losses of m converge, but rapid
convergence could only be shown on-sequence; the off-sequence behavior is
unclear. In probabilistic environments, neither the posterior nor the losses
converge, in general.

categories: cs.AI cs.IT cs.LG math.IT math.ST stat.TH


title: Flow-based analysis of Internet traffic

abstract:
  We propose flow-based analysis to estimate quality of an Internet connection.
Using results from the queuing theory we compare two expressions for backbone
traffic that have different scopes of applicability. A curve that shows
dependence of utilization of a link on a number of active flows in it describes
different states of the network. We propose a methodology for plotting such a
curve using data received from a Cisco router by NetFlow protocol, determining
the working area and the overloading point of the network. Our test is an easy
way to find a moment for upgrading the backbone.


title: Quanta: a Language for Modeling and Manipulating Information Structures

abstract:
  We present a theory for modeling the structure of information and a language
(Quanta) expressing the theory. Unlike Shannon's information theory, which
focuses on the amount of information in an information system, we focus on the
structure of the information in the system. For example, we can model the
information structure corresponding to an algorithm or a physical process such
as the structure of a quantum interaction. After a brief discussion of the
relation between an evolving state-system and an information structure, we
develop an algebra of information pieces (infons) to represent the structure of
systems where descriptions of complex systems are constructed from expressions
involving descriptions of simpler information systems. We map the theory to the
Von Neumann computing model of sequences/conditionals/repetitions, and to the
class/object theory of object-oriented programming (OOP).


title: Bayesian Information Extraction Network

abstract:
  Dynamic Bayesian networks (DBNs) offer an elegant way to integrate various
aspects of language in one model. Many existing algorithms developed for
learning and inference in DBNs are applicable to probabilistic language
modeling. To demonstrate the potential of DBNs for natural language processing,
we employ a DBN in an information extraction task. We show how to assemble
wealth of emerging linguistic instruments for shallow parsing, syntactic and
semantic tagging, morphological decomposition, named entity recognition etc. in
order to incrementally build a robust information extraction system. Our method
outperforms previously published results on an established benchmark domain.


title:
The Open Language Archives Community: An infrastructure for distributed
  archiving of language resources

abstract:
  New ways of documenting and describing language via electronic media coupled
with new ways of distributing the results via the World-Wide Web offer a degree
of access to language resources that is unparalleled in history. At the same
time, the proliferation of approaches to using these new technologies is
causing serious problems relating to resource discovery and resource creation.
This article describes the infrastructure that the Open Language Archives
Community (OLAC) has built in order to address these problems. Its technical
and usage infrastructures address problems of resource discovery by
constructing a single virtual library of distributed resources. Its governance
infrastructure addresses problems of resource creation by providing a mechanism
through which the language-resource community can express its consensus on
recommended best practices.


title: Monodic temporal resolution

abstract:
  Until recently, First-Order Temporal Logic (FOTL) has been little understood.
While it is well known that the full logic has no finite axiomatisation, a more
detailed analysis of fragments of the logic was not previously available.
However, a breakthrough by Hodkinson et.al., identifying a finitely
axiomatisable fragment, termed the monodic fragment, has led to improved
understanding of FOTL. Yet, in order to utilise these theoretical advances, it
is important to have appropriate proof techniques for the monodic fragment.
  In this paper, we modify and extend the clausal temporal resolution
technique, originally developed for propositional temporal logics, to enable
its use in such monodic fragments. We develop a specific normal form for
formulae in FOTL, and provide a complete resolution calculus for formulae in
this form. Not only is this clausal resolution technique useful as a practical
proof technique for certain monodic classes, but the use of this approach
provides us with increased understanding of the monodic fragment. In
particular, we here show how several features of monodic FOTL are established
as corollaries of the completeness result for the clausal temporal resolution
method. These include definitions of new decidable monodic classes,
simplification of existing monodic classes by reductions, and completeness of
clausal temporal resolution in the case of monodic logics with expanding
domains, a case with much significance in both theory and practice.


title: IGUANA Architecture, Framework and Toolkit for Interactive Graphics

abstract:
  IGUANA is a generic interactive visualisation framework based on a C++
component model. It provides powerful user interface and visualisation
primitives in a way that is not tied to any particular physics experiment or
detector design. The article describes interactive visualisation tools built
using IGUANA for the CMS and D0 experiments, as well as generic GEANT4 and
GEANT3 applications. It covers features of the graphical user interfaces, 3D
and 2D graphics, high-quality vector graphics output for print media, various
textual, tabular and hierarchical data views, and integration with the
application through control panels, a command line and different
multi-threading models.


title: Skip Graphs

abstract:
  Skip graphs are a novel distributed data structure, based on skip lists, that
provide the full functionality of a balanced tree in a distributed system where
resources are stored in separate nodes that may fail at any time. They are
designed for use in searching peer-to-peer systems, and by providing the
ability to perform queries based on key ordering, they improve on existing
search tools that provide only hash table functionality. Unlike skip lists or
other tree data structures, skip graphs are highly resilient, tolerating a
large fraction of failed nodes without losing connectivity. In addition,
constructing, inserting new nodes into, searching a skip graph, and detecting
and repairing errors in the data structure introduced by node failures can be
done using simple and straightforward algorithms.


title: Compositional competitiveness for distributed algorithms

abstract:
  We define a measure of competitive performance for distributed algorithms
based on throughput, the number of tasks that an algorithm can carry out in a
fixed amount of work. This new measure complements the latency measure of Ajtai
et al., which measures how quickly an algorithm can finish tasks that start at
specified times. The novel feature of the throughput measure, which
distinguishes it from the latency measure, is that it is compositional: it
supports a notion of algorithms that are competitive relative to a class of
subroutines, with the property that an algorithm that is k-competitive relative
to a class of subroutines, combined with an l-competitive member of that class,
gives a combined algorithm that is kl-competitive.
  In particular, we prove the throughput-competitiveness of a class of
algorithms for collect operations, in which each of a group of n processes
obtains all values stored in an array of n registers. Collects are a
fundamental building block of a wide variety of shared-memory distributed
algorithms, and we show that several such algorithms are competitive relative
to collects. Inserting a competitive collect in these algorithms gives the
first examples of competitive distributed algorithms obtained by composition
using a general construction.


title:
The WorldGrid transatlantic testbed: a successful example of Grid
  interoperability across EU and U.S. domains

abstract:
  The European DataTAG project has taken a major step towards making the
concept of a worldwide computing Grid a reality. In collaboration with the
companion U.S. project iVDGL, DataTAG has realized an intercontinental testbed
spanning Europe and the U.S. integrating architecturally different Grid
implementations based on the Globus toolkit. The WorldGrid testbed has been
successfully demonstrated at SuperComputing 2002 and IST2002 where real HEP
application jobs were transparently submitted from U.S. and Europe using native
mechanisms and run where resources were available, independently of their
location. In this paper we describe the architecture of the WorldGrid testbed,
the problems encountered and the solutions taken in realizing such a testbed.
With our work we present an important step towards interoperability of Grid
middleware developed and deployed in Europe and the U.S.. Some of the solutions
developed in WorldGrid will be adopted by the LHC Computing Grid first service.
To the best of our knowledge, this is the first large-scale testbed that
combines middleware components and makes them work together.


title:
Compact Approximation of Lattice Functions with Applications to
  Large-Alphabet Text Search

abstract:
  We propose a very simple randomised data structure that stores an
approximation from above of a lattice-valued function. Computing the function
value requires a constant number of steps, and the error probability can be
balanced with space usage, much like in Bloom filters. The structure is
particularly well suited for functions that are bottom on most of their domain.
We then show how to use our methods to store in a compact way the bad-character
shift function for variants of the Boyer-Moore text search algorithms. As a
result, we obtain practical implementations of these algorithms that can be
used with large alphabets, such as Unicode collation elements, with a small
setup time. The ideas described in this paper have been implemented as free
software under the GNU General Public License within the MG4J project
(http://mg4j.dsi.unimi.it/).


title: Concrete uses of XML in software development and data analysis

abstract:
  XML is now becoming an industry standard for data description and exchange.
Despite this there are still some questions about how or if this technology can
be useful in High Energy Physics software development and data analysis. This
paper aims to answer these questions by demonstrating how XML is used in the
IceCube software development system, data handling and analysis. It does this
by first surveying the concepts and tools that make up the XML technology. It
then goes on to discuss concrete examples of how these concepts and tools are
used to speed up software development in IceCube and what are the benefits of
using XML in IceCube's data handling and analysis chain. The overall aim of
this paper it to show that XML does have many benefits to bring High Energy
Physics software development and data analysis.


title: Parallel netCDF: A Scientific High-Performance I/O Interface

abstract:
  Dataset storage, exchange, and access play a critical role in scientific
applications. For such purposes netCDF serves as a portable and efficient file
format and programming interface, which is popular in numerous scientific
application domains. However, the original interface does not provide an
efficient mechanism for parallel data storage and access. In this work, we
present a new parallel interface for writing and reading netCDF datasets. This
interface is derived with minimum changes from the serial netCDF interface but
defines semantics for parallel access and is tailored for high performance. The
underlying parallel I/O is achieved through MPI-IO, allowing for dramatic
performance gains through the use of collective I/O optimizations. We compare
the implementation strategies with HDF5 and analyze both. Our tests indicate
programming convenience and significant I/O performance improvement with this
parallel netCDF interface.


title: Hyperdense Coding Modulo 6 with Filter-Machines

abstract:
  We show how one can encode $n$ bits with $n^{o(1)}$ ``wave-bits'' using still
hypothetical filter-machines (here $o(1)$ denotes a positive quantity which
goes to 0 as $n$ goes to infity). Our present result - in a completely
different computational model - significantly improves on the quantum
superdense-coding breakthrough of Bennet and Wiesner (1992) which encoded $n$
bits by $\lceil{n/2}\rceil$ quantum-bits. We also show that our earlier
algorithm (Tech. Rep. TR03-001, ECCC, See
ftp://ftp.eccc.uni-trier.de/pub/eccc/reports/2003/TR03-001/index.html) which
used $n^{o(1)}$ muliplication for computing a representation of the dot-product
of two $n$-bit sequences modulo 6, and, similarly, an algorithm for computing a
representation of the multiplication of two $n\times n$ matrices with
$n^{2+o(1)}$ multiplications can be turned to algorithms computing the exact
dot-product or the exact matrix-product with the same number of multiplications
with filter-machines. With classical computation, computing the dot-product
needs $\Omega(n)$ multiplications and the best known algorithm for matrix
multiplication (D. Coppersmith and S. Winograd, Matrix multiplication via
arithmetic progressions, J. Symbolic Comput., 9(3):251--280, 1990) uses
$n^{2.376}$ multiplications.


title:
Introduction to the CoNLL-2003 Shared Task: Language-Independent Named
  Entity Recognition

abstract:
  We describe the CoNLL-2003 shared task: language-independent named entity
recognition. We give background information on the data sets (English and
German) and the evaluation method, present a general overview of the systems
that have taken part in the task and discuss their performance.


title: A data Grid testbed environment in Gigabit WAN with HPSS

abstract:
  For data analysis of large-scale experiments such as LHC Atlas and other
Japanese high energy and nuclear physics projects, we have constructed a Grid
test bed at ICEPP and KEK. These institutes are connected to national
scientific gigabit network backbone called SuperSINET. In our test bed, we have
installed NorduGrid middleware based on Globus, and connected 120TB HPSS at KEK
as a large scale data store. Atlas simulation data at ICEPP has been
transferred and accessed using SuperSINET. We have tested various performances
and characteristics of HPSS through this high speed WAN. The measurement
includes comparison between computing and storage resources are tightly coupled
with low latency LAN and long distant WAN.


title: ATLAS Data Challenge 1

abstract:
  In 2002 the ATLAS experiment started a series of Data Challenges (DC) of
which the goals are the validation of the Computing Model, of the complete
software suite, of the data model, and to ensure the correctness of the
technical choices to be made. A major feature of the first Data Challenge (DC1)
was the preparation and the deployment of the software required for the
production of large event samples for the High Level Trigger (HLT) and physics
communities, and the production of those samples as a world-wide distributed
activity. The first phase of DC1 was run during summer 2002, and involved 39
institutes in 18 countries. More than 10 million physics events and 30 million
single particle events were fully simulated. Over a period of about 40 calendar
days 71000 CPU-days were used producing 30 Tbytes of data in about 35000
partitions. In the second phase the next processing step was performed with the
participation of 56 institutes in 21 countries (~ 4000 processors used in
parallel). The basic elements of the ATLAS Monte Carlo production system are
described. We also present how the software suite was validated and the
participating sites were certified. These productions were already partly
performed by using different flavours of Grid middleware at ~ 20 sites.


title: A Community Authorization Service for Group Collaboration

abstract:
  In "Grids" and "collaboratories," we find distributed communities of resource
providers and resource consumers, within which often complex and dynamic
policies govern who can use which resources for which purpose. We propose a new
approach to the representation, maintenance, and enforcement of such policies
that provides a scalable mechanism for specifying and enforcing these policies.
Our approach allows resource providers to delegate some of the authority for
maintaining fine-grained access control policies to communities, while still
maintaining ultimate control over their resources. We also describe a prototype
implementation of this approach and an application in a data management
context.


title: OVAL: the CMS Testing Robot

abstract:
  Oval is a testing tool which help developers to detect unexpected changes in
the behavior of their software. It is able to automatically compile some test
programs, to prepare on the fly the needed configuration files, to run the
tests within a specified Unix environment, and finally to analyze the output
and check expectations. Oval does not provide utility code to help writing the
tests, therefore it is quite independant of the programming/scripting language
of the software to be tested. It can be seen as a kind of robot which apply the
tests and warn about any unexpected change in the output. Oval was developed by
the LLR laboratory for the needs of the CMS experiment, and it is now
recommended by the CERN LCG project.


title: BlueOx: A Java Framework for Distributed Data Analysis

abstract:
  High energy physics experiments including those at the Tevatron and the
upcoming LHC require analysis of large data sets which are best handled by
distributed computation. We present the design and development of a distributed
data analysis framework based on Java. Analysis jobs run through three phases:
discovery of data sets available, brokering/assignment of data sets to analysis
servers, and job execution. Each phase is represented by a set of abstract
interfaces. These interfaces allow different techniques to be used without
modification to the framework. For example, the communications interface has
been implemented by both a packet protocol and a SOAP-based scheme. User
authentication can be provided either through simple passwords or through a GSI
certificates system. Data from CMS HCAL Testbeams, the L3 LEP experiment, and a
hypothetical high-energy linear collider experiment have been interfaced with
the framework.


title: Twelve Ways to Build CMS Crossings from ROOT Files

abstract:
  The simulation of CMS raw data requires the random selection of one hundred
and fifty pileup events from a very large set of files, to be superimposed in
memory to the signal event. The use of ROOT I/O for that purpose is quite
unusual: the events are not read sequentially but pseudo-randomly, they are not
processed one by one in memory but by bunches, and they do not contain orthodox
ROOT objects but many foreign objects and templates. In this context, we have
compared the performance of ROOT containers versus the STL vectors, and the use
of trees versus a direct storage of containers. The strategy with best
performances is by far the one using clones within trees, but it stays hard to
tune and very dependant on the exact use-case. The use of STL vectors could
bring more easily similar performances in a future ROOT release.


title: IceCube's Development Environment

abstract:
  When the IceCube experiment started serious software development it needed a
development environment in which both its developers and clients could work and
that would encourage and support a good software development process. Some of
the key features that IceCube wanted in such a environment were: the separation
of the configuration and build tools; inclusion of an issue tracking system;
support for the Unified Change Model; support for unit testing; and support for
continuous building. No single, affordable, off the shelf, environment offered
all these features. However there are many open source tools that address
subsets of these feature, therefore IceCube set about selecting those tools
which it could use in developing its own environment and adding its own tools
where no suitable tools were found. This paper outlines the tools that where
chosen, what are their responsibilities in the development environment and how
they fit together. The complete environment will be demonstrated with a walk
through of single cycle of the development process.


title: Installing, Running and Maintaining Large Linux Clusters at CERN

abstract:
  Having built up Linux clusters to more than 1000 nodes over the past five
years, we already have practical experience confronting some of the LHC scale
computing challenges: scalability, automation, hardware diversity, security,
and rolling OS upgrades. This paper describes the tools and processes we have
implemented, working in close collaboration with the EDG project [1],
especially with the WP4 subtask, to improve the manageability of our clusters,
in particular in the areas of system installation, configuration, and
monitoring. In addition to the purely technical issues, providing shared
interactive and batch services which can adapt to meet the diverse and changing
requirements of our users is a significant challenge. We describe the
developments and tuning that we have introduced on our LSF based systems to
maximise both responsiveness to users and overall system utilisation. Finally,
this paper will describe the problems we are facing in enlarging our
heterogeneous Linux clusters, the progress we have made in dealing with the
current issues and the steps we are taking to gridify the clusters


title: The Use of HepRep in GLAST

abstract:
  HepRep is a generic, hierarchical format for description of graphics
representables that can be augmented by physics information and relational
properties. It was developed for high energy physics event display applications
and is especially suited to client/server or component frameworks. The GLAST
experiment, an international effort led by NASA for a gamma-ray telescope to
launch in 2006, chose HepRep to provide a flexible, extensible and maintainable
framework for their event display without tying their users to any one graphics
application. To support HepRep in their GUADI infrastructure, GLAST developed a
HepRep filler and builder architecture. The architecture hides the details of
XML and CORBA in a set of base and helper classes allowing physics experts to
focus on what data they want to represent. GLAST has two GAUDI services:
HepRepSvc, which registers HepRep fillers in a global registry and allows the
HepRep to be exported to XML, and CorbaSvc, which allows the HepRep to be
published through a CORBA interface and which allows the client application to
feed commands back to GAUDI (such as start next event, or run some GAUDI
algorithm). GLAST's HepRep solution gives users a choice of client
applications, WIRED (written in Java) or FRED (written in C++ and Ruby), and
leaves them free to move to any future HepRep-compliant event display.


title: DIRAC - Distributed Infrastructure with Remote Agent Control

abstract:
  This paper describes DIRAC, the LHCb Monte Carlo production system. DIRAC has
a client/server architecture based on: Compute elements distributed among the
collaborating institutes; Databases for production management, bookkeeping (the
metadata catalogue) and software configuration; Monitoring and cataloguing
services for updating and accessing the databases. Locally installed software
agents implemented in Python monitor the local batch queue, interrogate the
production database for any outstanding production requests using the XML-RPC
protocol and initiate the job submission. The agent checks and, if necessary,
installs any required software automatically. After the job has processed the
events, the agent transfers the output data and updates the metadata catalogue.
DIRAC has been successfully installed at 18 collaborating institutes, including
the DataGRID, and has been used in recent Physics Data Challenges. In the near
to medium term future we must use a mixed environment with different types of
grid middleware or no middleware. We describe how this flexibility has been
achieved and how ubiquitously available grid middleware would improve DIRAC.


title: Operational Aspects of Dealing with the Large BaBar Data Set

abstract:
  To date, the BaBar experiment has stored over 0.7PB of data in an
Objectivity/DB database. Approximately half this data-set comprises simulated
data of which more than 70% has been produced at more than 20 collaborating
institutes outside of SLAC. The operational aspects of managing such a large
data set and providing access to the physicists in a timely manner is a
challenging and complex problem. We describe the operational aspects of
managing such a large distributed data-set as well as importing and exporting
data from geographically spread BaBar collaborators. We also describe problems
common to dealing with such large datasets.


title:
Learning to Order Facts for Discourse Planning in Natural Language
  Generation

abstract:
  This paper presents a machine learning approach to discourse planning in
natural language generation. More specifically, we address the problem of
learning the most natural ordering of facts in discourse plans for a specific
domain. We discuss our methodology and how it was instantiated using two
different machine learning algorithms. A quantitative evaluation performed in
the domain of museum exhibit descriptions indicates that our approach performs
significantly better than manually constructed ordering rules. Being
retrainable, the resulting planners can be ported easily to other similar
domains, without requiring language technology expertise.


title: A Model for Grid User Management

abstract:
  Registration and management of users in a large scale Grid computing
environment presents new challenges that are not well addressed by existing
protocols. Within a single Virtual Organization (VO), thousands of users will
potentially need access to hundreds of computing sites, and the traditional
model where users register for local accounts at each site will present
significant scaling problems. However, computing sites must maintain control
over access to the site and site policies generally require individual local
accounts for every user. We present here a model that allows users to register
once with a VO and yet still provides all of the computing sites the
information they require with the required level of trust. We have developed
tools to allow sites to automate the management of local accounts and the
mappings between Grid identities and local accounts.


title: Exploiting peer group concept for adaptive and highly available services

abstract:
  This paper presents a prototype for redundant, highly available and fault
tolerant peer to peer framework for data management. Peer to peer computing is
gaining importance due to its flexible organization, lack of central authority,
distribution of functionality to participating nodes and ability to utilize
unused computational resources. Emergence of GRID computing has provided much
needed infrastructure and administrative domain for peer to peer computing. The
components of this framework exploit peer group concept to scope service and
information search, arrange services and information in a coherent manner,
provide selective redundancy and ensure availability in face of failure and
high load conditions. A prototype system has been implemented using JXTA peer
to peer technology and XML is used for service description and interfaces,
allowing peers to communicate with services implemented in various platforms
including web services and JINI services. It utilizes code mobility to achieve
role interchange among services and ensure dynamic group membership. Security
is ensured by using Public Key Infrastructure (PKI) to implement group level
security policies for membership and service access.


title: POOL File Catalog, Collection and Metadata Components

abstract:
  The POOL project is the common persistency framework for the LHC experiments
to store petabytes of experiment data and metadata in a distributed and grid
enabled way. POOL is a hybrid event store consisting of a data streaming layer
and a relational layer. This paper describes the design of file catalog,
collection and metadata components which are not part of the data streaming
layer of POOL and outlines how POOL aims to provide transparent and efficient
data access for a wide range of environments and use cases - ranging from a
large production site down to a single disconnected laptops. The file catalog
is the central POOL component translating logical data references to physical
data files in a grid environment. POOL collections with their associated
metadata provide an abstract way of accessing experiment data via their logical
grouping into sets of related data objects.


title: The COMPASS Event Store in 2002

abstract:
  COMPASS, the fixed-target experiment at CERN studying the structure of the
nucleon and spectroscopy, collected over 260 TB during summer 2002 run. All
these data, together with reconstructed events information, were put from the
beginning in a database infrastructure based on Objectivity/DB and on the
hierarchical storage manager CASTOR. The experience in the usage of the
database is reviewed and the evolution of the system outlined.


title: The AliEn system, status and perspectives

abstract:
  AliEn is a production environment that implements several components of the
Grid paradigm needed to simulate, reconstruct and analyse HEP data in a
distributed way. The system is built around Open Source components, uses the
Web Services model and standard network protocols to implement the computing
platform that is currently being used to produce and analyse Monte Carlo data
at over 30 sites on four continents. The aim of this paper is to present the
current AliEn architecture and outline its future developments in the light of
emerging standards.