An actor model for rule-based systems

Our research originates from a study of the possibilities of integrating rules and objects in knowledge-based systems. In the present work, we are interested in the interactionist perspective of an object. The stepwise reasoning of a diagnostic expert system, possibly involving subgoaling and interactions with the environment, can be easily codified by means of production rules over proposition literals. This set of rules can be graphically represented in a network manner denoting the relations between the rules. The individual nodes in the network can be expressed by means of autonomous objects and their relations, interpreted as possible communications between them. The objects are given a structure and a proper behaviour and cooperate for performing logical reasoning by means of forward and backward chaining inference processes. Therefore, designing this system implies addressing several basic issues such as inter-object communications and their synchronization. The problem here is not necessarily to develop a great intelligence locally but to develop strong networks of good communicators. This approach belongs to the interactionist representation current, where objects are called actors. In principle, the actors may carry out computation in parallel and provide a conceptual foundation for massively concurrent object-oriented paradigms. From this point of view, a system allowing for the simultaneous investigation of several rules and premises in the forward or the backward chaining would be significantly more efficient.     

A formal approach to object-oriented databases

Object-oriented database systems are the focus of current research and development efforts. Yet, there is no commonly accepted object model, nor is it clear whether such a model can be developed. This paper reports on efforts to develop a formal framework that contains most features found in current object oriented database systems. The framework contains two parts. The first is a structural object model, including concepts such as structured objects, identity, and some form of inheritance. For this model, we explain the distinction between values and (abstract) objects, describe a system as a directed graph, and discuss declarative languages. The second part deals with higher-order concepts, such as classes and functions as data, methods, and inheritance. This part is a sketch, and leaves many issues unresolved. Throughout the paper, the emphasis is on logic-oriented modeling.     

A functional size measurement method for object-oriented conceptual schemas: design and evaluation issues

Functional Size Measurement (FSM) methods are intended to measure the size of software by quantifying the functional user requirements of the software. The capability to accurately quantify the size of software in an early stage of the development lifecycle is critical to software project managers for evaluating risks, developing project estimates and having early project indicators. In this paper, we present OO-Method Function Points (OOmFP), which is a new FSM method for object-oriented systems that is based on measuring conceptual schemas. OOmFP is presented following the steps of a process model for software measurement. Using this process model, we present the design of the measurement method, its application in a case study, and the analysis of different evaluation types that can be carried out to validate the method and to verify its application and results.     

Logical foundations for representing object-oriented systems

Abstract

Object-oriented programming languages are designed for computing or simulating the behaviour of interacting objects, but their encapsulated contexts and procedural methods are not well suited to non-procedural techniques in theorem provers, optimizers, and automated design and analysis tools. Logic is the non-procedural system par excellence, but the predicate calculus notation for logic is awkward for representing and reasoning about encapsulated contexts. Conceptual graphs are a graphic system of logic that is better suited to O-O systems. First, they explicitly represent the contexts that are ignored or obscured in predicate calculus. Second, Peirce's rules of inference for reasoning with graphs are explicitly formulated in terms of contexts and the conditions for importing and exporting information from contexts. This article describes the context mechanisms of conceptual graphs, the rules of inference for reasoning with the graphs, and their use as a design language for object-oriented systems.     

A hybrid analytic/rule-based approach to reservoir system management during flood

The article presents an approach to real-time operation of a water retention reservoir during flood. Water releases are calculated repetitively on the basis of two-variant inflow forecasts and some expert knowledge. During every intervention of the control algorithm, an optimization problem with the expected value type performance index is solved. In the paper, the basic characteristics of trajectories of outflows resulting from the application of this control method are analyzed. Afterwards, the results of the series of simulation experiments based on a large set of historical data concerning a big Polish reservoir are presented.     

ODE: a tool for distributing object-oriented applications

Object-oriented applications are increasingly being deployed in distributed computing environments. Technologies, such as Java RMI, and architectures, such as CORBA, DCOM, and Enterprise Java Beans, are facilitating and enhancing this trend. The performance and eventual success of these applications is dependent on distribution decisions made by the application designer. This decision is a complex one, involving a large number of alternatives and multiple conflicting criteria. Rigorous approaches for effective distribution of object-oriented applications are still lacking. This paper describes the implementation of a practical and effective approach for distributing object-oriented applications. A prototype decision support system—object distribution environment (ODE)—that implements the approach in the form of a user-friendly tool for the design of distributed object-oriented applications is described. ODE has been successfully used in the distribution of a real world distributed object-oriented system.     

A rule-based approach for robust clump splitting

This paper presents a robust rule-based approach for the splitting of binary clumps that are formed by objects of diverse shapes and sizes. First, the deepest boundary pixels, i.e., the concavity pixels in a clump, are detected using a fast and accurate scheme. Next, concavity-based rules are applied to generate the candidate split lines that join pairs of concavity pixels. A figure of merit is used to determine the best split line from the set of candidate lines. Experimental results show that the proposed approach is robust and accurate.     

Migration in object-oriented database systems—A practical approach

Object-oriented database systems are designed to meet the requirements of advanced database applications such as computer-integrated manufacturing. These requirements may evolve in the course of time and may require the migration of the database application from one object-oriented database system to another. Traditional migration approaches for relational database systems fail when applied to object-oriented database systems. The goal of this paper is to fill this gap. The paper describes a framework for the migration of object-oriented database applications. Our approach is based on a detailed analysis of the involved database systems, of the application's database requirements, and of the resources available for the database migration. We illustrate our framework by means of a case study, which is migrating an electronic planning board system from the object-oriented database system ONTOS to ObjectStore.     

A rule-based system for dimensional analysis of glass containers

A frame-based vision system has been developed. Frames are homogeneous containing two slots: for the data and algorithms relating to a data type. Each frame may follow forward or backward chaining search strategies or may invoke procedural code. Any frame may call upon any other frame to perform some analysis and results are returned with an assessment of the degree of certainty of the result. The degree of certainty is used by the system in assessing the conclusions reached. As an example of the system's use, dimensional analysis of glass containers has been performed.     

A framework for object migration in object-oriented databases

This article presents a framework developed for accomodating various object migrations in ‘statically-typed’ object databases. Requirements for supporting object migrations are stipulated, and a conceptual model for describing and facilitating different kinds of migrations is described. Associated issues of controlling such migrations are then addressed, along with an initial investigation on the interence of implied migration paths and the completeness of migration operators. Some guidelines are then given to help users conduct migrations more effectively. An implementation prototype on top of an object-oriented database system was built, which embodies full support of all migration types specified in the migration model.     

A method of object-oriented information management for layout design

During the layout design process, the spatial arrangement of components in an engineering system is developed in order to meet design goals and constraints. Proper organization of the information involved in this process enhances the quality of layout designs. The organization of information is accomplished through the use of the techniques and methods existing in the information management field. Using the object-oriented technique, a method was developed to guide the design of information management systems that support the layout design process. The method was developed in a case study involving, the layout design of automobile engine bay compoenents.     

Systemic approach to fuzzy logic formalization for approximate reasoning

L.A. Zadeh, E.H. Mamdani, M. Mizumoto, et al., R.A. Aliev and A. Tserkovny have proposed methods for fuzzy reasoning in which antecedents and consequents involve fuzzy conditional propositions of the form “If x is A then y is B”, with A and B being fuzzy concepts (fuzzy sets). A formulation of fuzzy antecedent/consequent chains is one of the most important topics within a wide spectrum of problems in fuzzy sets in general and approximate reasoning, in particular. From the analysis of relevant research it becomes clear that for this purpose, a so-called fuzzy conditional inference rules comes as a viable alternative. In this study, we present a systemic approach toward fuzzy logic formalization for approximate reasoning. For this reason, we put together some comparative analysis of fuzzy reasoning methods in which antecedents contain a conditional proposition with fuzzy concepts and which are based on implication operators present in various types of fuzzy logic. We also show a process of a formation of the fuzzy logic regarded as an algebraic system closed under all its operations. We examine statistical characteristics of the proposed fuzzy logic. As the matter of practical interest, we construct a set of fuzzy conditional inference rules on the basis of the proposed fuzzy logic. Continuity and stability features of the formalized rules are investigated.     

An object-oriented blackboard based approach for automated finite element modeling and analysis of multichip modules

This paper addresses the application of the blackboard system architecture and object-oriented data abstraction techniques to the domain of finite element modeling and analysis. Specifically, a hierarchical object-oriented database was used to represent the physical system at different levels of abstraction including the user-defined physical system level, a computer-generated, simplified physical model level, and the finite element model level. Object link relationships within a given abstraction level and across different abstraction levels resulted in seamless bidirectional information exchange. The blackboard system architecture employed provided a framework for distributed cooperative problem solving, for the application of simplifying domain-specific modeling assumptions, and for integrating the various software modules that are involved in the entire finite element modeling and analysis process. These methodologies were implemented in a prototype computational tool calledIMCMA theIntelligentMultichipModuleAnalyzer. An example illustrates howIMCMA automates finite element thermal analysis of small integrated circuit features in multichip modules through a two-step finite element submodeling process.     

一个面向对象的二级并发模型

本文提出了一个面向对象的二级并发模型ＦＯＲＣＥ－Ｍｏｄｅｌ．它从需求规范的角度充分开发对象间和对象内两个层次上的并行性，从而将面向对象与并发性有机地结合起来，提供了有效的实时系统建模框架．基于该模型，我们开发了一个多视点可视规范语言族ＦＯＲＣＥ－Ｌａｎｇｕａｇｅ．     

A framework for distributing object-oriented designs

In response to the increasing demand of information processing, the object-oriented and client-server paradigms are becoming more pervasive. While implementation solutions integrating these two paradigms are widespread, there is minimal evidence that the merging of these two concepts has been considered at the design level. Specifically, object-oriented designs remain sequential in essence, and their mapping to a given distributed object-oriented programming language is left to the creativity and/or expertise of software engineers. In this paper, we propose a quantitative approach and a supporting tool to assist the designer in the distribution process. The metrics presented provide an easy way, but still consistent and reliable, to gauge the distribution suitability of various object-oriented design entities. Published online: 29 August 2002     

A stochastic graph grammar for compositional object representation and recognition

This paper illustrates a hierarchical generative model for representing and recognizing compositional object categories with large intra-category variance. In this model, objects are broken into their constituent parts and the variability of configurations and relationships between these parts are modeled by stochastic attribute graph grammars, which are embedded in an And-Or graph for each compositional object category. It combines the power of a stochastic context free grammar (SCFG) to express the variability of part configurations, and a Markov random field (MRF) to represent the pictorial spatial relationships between these parts. As a generative model, different object instances of a category can be realized as a traversal through the And-Or graph to arrive at a valid configuration (like a valid sentence in language, by analogy). The inference/recognition procedure is intimately tied to the structure of the model and follows a probabilistic formulation consisting of bottom-up detection steps for the parts, which in turn recursively activate the grammar rules for top-down verification and searches for missing parts. We present experiments comparing our results to state of art methods and demonstrate the potential of our proposed framework on compositional objects with cluttered backgrounds using training and testing data from the public Lotus Hill and Caltech datasets.     

A graph-based generic type system for object-oriented programs

We present a graph-basedmodel of a generic type system for an OO language. The type system supports the features of recursive types, generics and interfaces, which are commonly found in modern OO languages such as Java. In the classical graph theory, we define type graphs, instantiation graphs and conjunction graphs that naturally illustrate the relations among types, generics and interfaces within complex OO programs. The model employs a combination of nominal and anonymous nodes to represent respectively types that are identified by names and structures, and defines graph-based relations and operations on types including equivalence, subtyping, conjunction and instantiation. Algorithms based on the graph structures are designed for the implementation of the type system. We believe that this type system is important for the development of a graph-based logical foundation of a formal method for verification of and reasoning about OO programs.     

A fully abstract semantics of classes for Object-Z

This paper presents a fully abstract semantics of classes for the object oriented formal specification language Object-Z. Such a semantics includes no unnecessary syntactic details and, hence, describes a class in terms of the external behaviour of its objects only. The semantics, based on an extension of existing process models, defines a notion of behavioural equivalence which is stronger than that of CSP and weaker than that of CCS.     

A tool for measuring inheritance coupling in object-oriented systems

Analyzing object-oriented systems in order to evaluate their quality gains its importance as the paradigm continues to increase in popularity. Consequently, several object-oriented metrics have been proposed to evaluate different aspects of these systems such as class coupling. In object-oriented design, three types of coupling may exist between classes: inheritance coupling, interaction coupling, and component coupling. This paper presents a tool for measuring inheritance coupling in object-oriented systems.