Papers by Babis Theodoulidis
A controller synthesis algorithm for building self-adaptive software
Information & Software Technology, 2004
A novel approach for building self-adaptive software based on a controller synthesis algorithm is... more A novel approach for building self-adaptive software based on a controller synthesis algorithm is presented. Self-adaptive software is a relatively new idea aiming at producing applications that can readily adapt in the face of changing user needs, desires and environment. Self-adaptive software has multiple ways of accomplishing its purpose, enough knowledge of its construction and is capable of changing behaviour when it does not accomplish its goal or when better functionality or performance is possible. The ...
The purpose of this paper is to study the problem of pattern classification as this is presented ... more The purpose of this paper is to study the problem of pattern classification as this is presented in the context of data mining. Among the various approaches we focus on the use of Fuzzy Logic for pattern classification, due to its close relation to human thinking. More specifically, this paper presents a heuristic fuzzy method for the classification of numerical data, followed by the design and the implementation of its corresponding tool (Fuzzy Miner). The initial idea comes from the fact that fuzzy systems are universal approximators of any real continuous function. An approximation method coming from the domain of fuzzy control is appropriately adjusted into pattern classification and an "adaptive" procedure is proposed and developed for deriving highly accurate linguistic if-then rules. Extensive simulation tests are performed to demonstrate the performance and advantages of Fuzzy Miner, as well as its potential commercial benefits over a real world scenarion. â€
Journal of Visual Languages and Computing, 2003
The visual senses for humans have a unique status, offering a very broadband channel for informat... more The visual senses for humans have a unique status, offering a very broadband channel for information flow. Visual approaches to analysis and mining attempt to take advantage of our abilities to perceive pattern and structure in visual form and to make sense of, or interpret, what we see. Visual Data Mining techniques have proven to be of high value in exploratory data analysis and they also have a high potential for mining large databases. In this work, we try to investigate and expand the area of visual data mining by proposing new visual data mining techniques for the visualization of mining outcomes. r
Visual Data Mining and Modelling Techniques
Sigmod Record, 1994
Temporal databases has been an active area of research for the the last fteen years, with a corpu... more Temporal databases has been an active area of research for the the last fteen years, with a corpus nearing 800 papers. While most applications need to store time-varying data, there are no widely used commercial temporal databases. A primary reason for the absence of technology transfer from research to practice is the lack of a commonly accepted consensus data model or query language upon which to base research and development. Even the terminology is inconsistent.
CHOROCHRONOS has been a fruitful and enjoyable project. It contributed many innovative ideas in t... more CHOROCHRONOS has been a fruitful and enjoyable project. It contributed many innovative ideas in the areas of ontology and data modeling, query evaluation and prototype systems for spatio-temporal databases. Our ideas have already found uses in various application domains such as moving object databases (see Chapter 4), environmental information systems (see the Dedale application in Chapter 5), interactive multimedia applications and virtual worlds (see Chapter 8).
Sigmod Record, 1994
Temporal databases has been an active area of research for the the last fteen years, with a corpu... more Temporal databases has been an active area of research for the the last fteen years, with a corpus nearing 800 papers. While most applications need to store time-varying data, there are no widely used commercial temporal databases. A primary reason for the absence of technology transfer from research to practice is the lack of a commonly accepted consensus data model or query language upon which to base research and development. Even the terminology is inconsistent.
Sigmod Record, 1994
Temporal databases has been an active area of research for the the last fteen years, with a corpu... more Temporal databases has been an active area of research for the the last fteen years, with a corpus nearing 800 papers. While most applications need to store time-varying data, there are no widely used commercial temporal databases. A primary reason for the absence of technology transfer from research to practice is the lack of a commonly accepted consensus data model or query language upon which to base research and development. Even the terminology is inconsistent.
Recent efforts in spatial and temporal data models and database systems attempt to achieve an app... more Recent efforts in spatial and temporal data models and database systems attempt to achieve an appropriate kind of interaction between the two areas. This paper reviews the different types of spatio-temporal data models that have been proposed in the literature as well as new theories and concepts that have emerged. It provides an overview of previous achievements within the domain and critically evaluates the various approaches through the use of a case study and the construction of a comparison framework. This comparative review is followed by a comprehensive description of the new lines of research that emanate from the latest efforts inside the spatio-temporal research community.
The TAU Time Model
ABSTRACT
The TAU Temporal Object Model
Synopsis This report presents the TAU Temporal Object Model. The TAU Model is a high level data m... more Synopsis This report presents the TAU Temporal Object Model. The TAU Model is a high level data model that extends the ODMG Object Model in order to support temporal semantics. The basic concepts introduced by the TAU Model are valid time, transaction time, temporal objects, temporal extents, lifespans, temporal attributes, temporal relationships, property histories and temporal literals.
Building Autonomic Computing Systems Based on Ontological Component Models and a Controller Synthesis Algorithm
A novel approach for building autonomic computing systems is presented. Autonomic computing syste... more A novel approach for building autonomic computing systems is presented. Autonomic computing systems are systems which are self-managed, self-healing, self-organized, ultra-reliable, robust, and flexible. These systems have multiple ways of accomplishing their purpose, and are capable of reconfiguring themselves in order to optimize their performance, achieve their goals under varying and unpredictable conditions, recover from internal faults and protect themselves. The presented approach for building autonomic computing systems is based on an extension of Bunge ontology and the Bunge-Wand-Weber (BWW) models. An extended ontology is presented which models a system as an organized whole exhibiting a coherent and useful overall behavior. Ontological component models captured using software engineering diagrams enable these systems to have self- awareness on their construction, their available resources, their external environment, and their goals. Self-organization, self-adaptation and self-healing are achieved by employing a controller synthesis algorithm based on the Ramadge and Wonham supervisory control theory of discrete event systems.
The TEMPORA paradigm for the development of large data intensive, transaction oriented informatio... more The TEMPORA paradigm for the development of large data intensive, transaction oriented information systems explicitly recognises the role of organisational policy within an information system, and visibly maintains this policy throughout the software development process, from requirements specifications through to an executable implementation. This paper introduces the External Rule Language of the TEMPORA conceptual modelling formalism, and describes how it is used to captured and model business organisational policy. The syntax and semantics of the language are presented, together with a number of examples drawn from a realistic case study.
Information Systems Journal, 1991
Abstract. Recent years have witnessed a growing realization that the development of large data-in... more Abstract. Recent years have witnessed a growing realization that the development of large data-intensive, transaction-oriented information systems is becoming increasingly more difficult as user requirements become broader and more sophisticated. Contemporary approaches have been criticized for producing systems which are difficult to maintain and which provide little assistance in organizational developments. This paper introduces the TEMPORA paradigm, which is currently under development and which advocates a closer alignment between organizational policy and information system functionality. This viewpoint impacts on a number of critical issues related to the development process of information systems most notably in the nature of conceptual models, the discipline adopted for the development, the type of support provided by CASE tools and the run-time environment. The paper introduces the philosophy and architecture of the TEMPORA paradigm and describes the conceptual models, tools and run-time environment which render such an approach a feasible undertaking.
Building Autonomic Computing Systems Based on Ontological Component Models and a Controller Synthesis Algorithm
A novel approach for building autonomic computing systems is presented. Autonomic computing syste... more A novel approach for building autonomic computing systems is presented. Autonomic computing systems are systems which are self-managed, self-healing, self-organized, ultra-reliable, robust, and flexible. These systems have multiple ways of accomplishing their purpose, and are capable of reconfiguring themselves in order to optimize their performance, achieve their goals under varying and unpredictable conditions, recover from internal faults and protect themselves. The presented approach for building autonomic computing systems is based on an extension of Bunge ontology and the Bunge-Wand-Weber (BWW) models. An extended ontology is presented which models a system as an organized whole exhibiting a coherent and useful overall behavior. Ontological component models captured using software engineering diagrams enable these systems to have self- awareness on their construction, their available resources, their external environment, and their goals. Self-organization, self-adaptation and self-healing are achieved by employing a controller synthesis algorithm based on the Ramadge and Wonham supervisory control theory of discrete event systems.
Information Systems Journal, 1991
Abstract. Recent years have witnessed a growing realization that the development of large data-in... more Abstract. Recent years have witnessed a growing realization that the development of large data-intensive, transaction-oriented information systems is becoming increasingly more difficult as user requirements become broader and more sophisticated. Contemporary approaches have been criticized for producing systems which are difficult to maintain and which provide little assistance in organizational developments. This paper introduces the TEMPORA paradigm, which is currently under development and which advocates a closer alignment between organizational policy and information system functionality. This viewpoint impacts on a number of critical issues related to the development process of information systems most notably in the nature of conceptual models, the discipline adopted for the development, the type of support provided by CASE tools and the run-time environment. The paper introduces the philosophy and architecture of the TEMPORA paradigm and describes the conceptual models, tools and run-time environment which render such an approach a feasible undertaking.
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Papers by Babis Theodoulidis