Selected Publications
2001
- A. Bondavalli, M. Dal Cin, D. Latella, I. Majzik, A. Pataricza and G. Savoia:
Dependability Analysis in the Early Phases of UML
Based System Design
International Journal of Computer Systems - Science & Engineering, Vol.
16 (5), Sep 2001, pp. 265-275.
A thorough system specification is insufficient to guarantee that
a computer system will adequately perform its tasks during its
entire life cycle. The early evaluation of system characteristics
like dependability, correctness and performance is necessary to
assess the conformance of the system under development to its
targets. This paper presents the results achieved so far to
develop an integrated environment, where design tools based on the
UML (Unified Modeling Language) are augmented with validation and
analysis techniques that provide useful information in the early
phases of system design. Automatic transformations are defined for
the generation of models to capture system behavioral properties,
dependability and performance.
- András Pataricza, Béla Tolvaj:
Data mining techniques in the experimental analysis
of dependability
In: Proceedings of the DDECS 2001 Workshop, April 2001, Gyôr, Hungary,
pp. 273-280.
Abstract: Frequently the experimentation in the form of a post
mortem analysis or fault injection experiment aim to
reveal the correlation between some potential faults
and the failure triggered by them. Note, that pattern
sensitive failures are the most typical ones in
software based systems. Therefore the analysis of
complex systems must cope with a large population of
system logs, where each individual pattern is large
both in the terms of temporal duration, and in the
number of signals and values to be recorded
simultaneously. In the current paper we summarize our
preliminary experiences for using data mining in the
analysis phase of such error logs. The pilot
experience was carried out on error logs from a Web
server, however it must be pointed out, that a very
similar approach based on the same technology can be
useful in a variety of dependability-related fields as
well, like fault injection based testing, stratified
testing, etc.
- Balázs Polgár, Szilárd Nováki, András
Pataricza, Ferenc Friedler:
A Process-Graph Based Formulation of the Syndrome-Decoding
Problem
In: Proceedings of the DDECS 2001 Workshop, April 2001, Gyôr, Hungary,
pp. 267-272.
Abstract: Diagnostics is one of the core problems in assuring
the dependability of complex information technology
systems. Nowadays diagnostics does not only a simple
activity for identifying faulty hardware resources,
but more and more it is a complex activity
necessitating to cover both the hardware and software
aspects. The increasing frequency of transient errors
require more and more sophisticated diagnosis
technologies, which also support the subsequent phases
of fault handling as well, like damage confinement and
reconfiguration. In practice, however one of the
basic problems is the proper handling of the high
complexity of the diagnostic process. One of the
intrinsic assumptions behind all diagnostic algorithms
is the notion of a maximum likelihood diagnosis.
Frequently this assumption appears simply as "more
faults occur with lower frequency than a few
ones". Thus, the diagnostics aims at a minimal set of
faulty elements compatible with the syndrome. Other
approaches use an explicit notion of fault
probabilities and assign different probabilities to
different elements. In the present work, the
diagnostics has been formulated as a maximization
problem, moreover, it has been solved by state of the
art technologies from the field of operations
research.
- Zs. Pap, I. Majzik, A. Pataricza and A. Szegi:
Completeness and Consistency Analysis of UML Statechart
Specifications
In: Proceedings of the DDECS 2001 Workshop, April 2001, Gyôr, Hungary,
pp. 83-90.
Abstract: This paper describes methods and tools for
automatic safety analysis of UML statechart
specifications. Two types of analysis are
presented. The first one checks completeness and
consistency based on the static structure of the
specification, thus it does not requires the
generation of the reachability graph. Accordingly,
this method scales up well to large systems. The
second one performs dynamic analysis by checking
safety related reachability properties with the help
of a model checker. It is restricted to core critical
parts of the system. Two approaches of the
implementation of the static checking are
discussed. The use of the tools is presented by a case
study.
- Huszerl G. and Majzik I.:
Modelling and Analysis of Redundancy Management in Distributed
Object-Oriented Systems by Using UML Statecharts
In: Proc. of the 27th Euromicro Conference, pp. 200-207., Warsaw, Poland, 4-6.
September 2001.
Abstract: The paper presents techniques that enable the modeling and analysis
of redundancy schemes in distributed object-oriented systems. The replication
manager, as core part of the redundancy scheme, is modeled by using UML statecharts.
The flexibility of the statechart-based modeling, which includes event processing
and state hierarchy, enables an easy and efficient modeling of replication
strategies as well as repair and recovery policies. The statechart is transformed
to a Petri-net based dependability model, which also incorporates the models
of the replicated objects. By the analysis of the Petri-net model the designer
can obtain reliability and availability measures that can be used in the early
phases of the design to compare alternatives and find dependability bottlenecks.
Our approach is illustrated by an example.
- O. Dobán, A. Pataricza:
Cost Estimation Driven Software Development Process
In: Proc. of the 27th Euromicro Conference, pp. 208-215., Warsaw, Poland, 4-6.
September 2001.
Abstract: The need for more and more dependable systems has been increased
in the last decades. Strategic decisions during the design of these dependable
systems require the joint control of the estimated cost and the product quality.
Cost efficiency and development time became the most important factors of
the software development process according to the international trends. The
estimation of the cost remains a difficult problem till yet, despite of the
use of standard, easy to understand modelling languages. On the other hand,
no working environment is known supporting the gradually refined cost estimation
derived automatically from the formal product models. In this paper the experiments
of a pseudo cost estimation are detailed with a special emphasis on the cost
estimation driven system design.
- A. Pataricza, Gy. Csertán, O. Dobán, A. Gábor, J.
Sziray:
Process Modeling and Optimization in UML
IEEE International Conference on Intelligent Engineering Systems, INES-2001,
Proceedings, pp. 457-461, Helsinki, September 16-18, 2001.
Abstract: This paper presents an overview of the results achieved in the framework
of a project aiming at a commercial off the shelf (COTS) based, object-oriented
design environment of UML-based process modeling and optimization. It reviews
the de facto industry standards for Business Process Modeling (BPM) and mathematical
problem definition and model exchange from the point of view of their applicability
in modeling physical production processes.
- Zs. Pap, I. Majzik, A. Pataricza:
Checking General Safety Criteria on UML Statecharts
20th International Conference on Computer Safety, Reliability and Security 2001
(SafeComp 2001), Proceedings (Springer Lecture Notes in Computer Science, No.
2187), pp. 46-55, September 25-27, 2001.
Abstract: This paper describes methods and tools for automated safety analysis
of UML statechart specifications. The general safety criteria described in
the literature are reviewed and automated analysis techniques are proposed.
The techniques based on OCL expressions and graph transformations are detailed
and their limitations are discussed. To speed up the checker methods, a reduced
form for UML statecharts is introduced. Using this form, the correctness and
completeness of some checker methods can be proven. An example illustrates
the application of the tools developed so far.
- Zs. Pap, D. Petri:
A Design Pattern of the User Interface of Safety-critical
Systems
IWCIT 2001, ISBN 80-7078-907-7, pp. 77., Ostrava, International Workshop on
Control and Information Technology, Sept. 19th-20th
Abstract: This paper describes a design pattern for safety-critical user interfaces.
This design is a version on of the Model-View-Controller architecture, but
accepts safety and ergonomics criteria based on the literature.
- A. Pataricza:
Semi-decisions in the validation of dependable systems
Supplementary of the Proc. IEEE DSN'01, The IEEE International Conference
on Dependable Systems and Networks, pp. 114-115, Göteborg, Sweden, 30.
June - 4. July 2001.
Abstract: The current paper reports about an ongoing research to prove the
correctness of designs described in UML. The most specific feature of the
approach taken is the objective to prove the correct functioning of the target
design even in the presence of faults anticipated in a predefined fault model.
- Dániel Varró, Szilvia Gyapay and
András Pataricza:
Automatic Transformation of UML Models for System Verification
J. Whittle et al. (eds): Proceedings of the WTUML 2001:
Workshop on Transformations in UML, pp. 123-127.
BibTex
Abstract: The design of complex, dependable systems requires a precise formal
verification of design decisions during the system modelling phase. For
that reason, the mathematical models of various formal verification tools
are planned to be automatically derived from the system model described
by UML-diagrams. In the current paper, a general framework for an automated
model transformation system is outlined providing a uniform formal description
method of such transformations by applying the powerful computational paradigm
of graph transformation.
Keywords: formal verification, UML, model transformation.