788 research outputs found
The Digital Anatomist Foundational Model Server
(no abstract
A Geometric Approach to the Problem of Unique Decomposition of Processes
This paper proposes a geometric solution to the problem of prime
decomposability of concurrent processes first explored by R. Milner and F.
Moller in [MM93]. Concurrent programs are given a geometric semantics using
cubical areas, for which a unique factorization theorem is proved. An effective
factorization method which is correct and complete with respect to the
geometric semantics is derived from the factorization theorem. This algorithm
is implemented in the static analyzer ALCOOL.Comment: 15 page
SAGA: A project to automate the management of software production systems
The SAGA system is a software environment that is designed to support most of the software development activities that occur in a software lifecycle. The system can be configured to support specific software development applications using given programming languages, tools, and methodologies. Meta-tools are provided to ease configuration. The SAGA system consists of a small number of software components that are adapted by the meta-tools into specific tools for use in the software development application. The modules are design so that the meta-tools can construct an environment which is both integrated and flexible. The SAGA project is documented in several papers which are presented
Semantic Embedding of Petri Nets into Event-B
We present an embedding of Petri nets into B abstract systems. The embedding
is achieved by translating both the static structure (modelling aspect) and the
evolution semantics of Petri nets. The static structure of a Petri-net is
captured within a B abstract system through a graph structure. This abstract
system is then included in another abstract system which captures the evolution
semantics of Petri-nets. The evolution semantics results in some B events
depending on the chosen policies: basic nets or high level Petri nets. The
current embedding enables one to use conjointly Petri nets and Event-B in the
same system development, but at different steps and for various analysis.Comment: 16 pages, 3 figure
The Train Benchmark: cross-technology performance evaluation of continuous model queries
In model-driven development of safety-critical
systems (like automotive, avionics or railways), well-
formedness of models is repeatedly validated in order to
detect design flaws as early as possible. In many indus-
trial tools, validation rules are still often implemented by
a large amount of imperative model traversal code which
makes those rule implementations complicated and hard
to maintain. Additionally, as models are rapidly increas-
ing in size and complexity, efficient execution of validation rules is challenging for the currently available tools.
Checking well-formedness constraints can be captured by
declarative queries over graph models, while model update
operations can be specified as model transformations. This
paper presents a benchmark for systematically assessing the
scalability of validating and revalidating well-formedness
constraints over large graph models. The benchmark defines
well-formedness validation scenarios in the railway domain:
a metamodel, an instance model generator and a set of well-
formedness constraints captured by queries, fault injection
and repair operations (imitating the work of systems engi-
neers by model transformations). The benchmark focuses
on the performance of query evaluation, i.e. its execution
time and memory consumption, with a particular empha-
sis on reevaluation. We demonstrate that the benchmark
can be adopted to various technologies and query engines,
including modeling tools; relational, graph and semantic
databases. The Train Benchmark is available as an open-
source project with continuous builds from
https://github.
com/FTSRG/trainbenchmark
Evaluation of Optimization Strategies for Incremental Graph Queries
The last decade brought considerable improvements in distributed storage and query technologies, known as NoSQL systems. These systems provide quick evaluation of simple retrieval operations and are able to answer certain complex queries in a scalable way, albeit not instantly. Providing scalability and quick response times at the same time for querying large data sets is still a challenging task. Evaluating complex graph queries is particularly difficult, as it requires lots of join, antijoin and filtering operations. This paper presents optimization techniques used in relational database systems and applies them on graph queries. We evaluate various query plans on multiple datasets and discuss the effect of different optimization techniques
Modular and composable extensions to smalltalk using composition filters
Current and future trends in computer science require extensions to Smalltalk. Rather than arguing for particular language mechanisms to deal with specific requirements, in this position paper we want to make a case for two requirements that Smalltalk extensions should fulfill. The first is that the extensions must be integrated with Smalltalk without violating its basic object model. The second requirement is that extensions should allow for defining objects that are still adaptable, extensible and reusable, and in particular do not cause inheritance anomalies. We propose the composition filters model as a framework for language extensions that fulfills these criteria. Its applicability to solving various modeling problems is briefly illustrated
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