Extensible software systems play an important role in prototyping environments where a fast compile-and-test turnaround is required. Typically, extensible software systems combine ways to reuse code, an approach to ob...
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Classifying coins found during excavation is a challenging task for the archaeologist. This paper describes a multimedia system designed to assist the archaeologist by enabling him either to classify coins based on a ...
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Classifying coins found during excavation is a challenging task for the archaeologist. This paper describes a multimedia system designed to assist the archaeologist by enabling him either to classify coins based on a pre-existing catalogue or to draw up his own catalogue for specific purposes. The system can also be used to train novices in the field: following an initial screening, the archaeologist only has to examine coins specifically requiring his expertise. A case study uses coins minted in Salerno 800-1200 AD, but the system has been designed to classify any set of coins by simply changing the underlying knowledge base. Very little training is required to operate the user-friendly system, which runs on multimedia PCs, as it is written using the C++ language and makes full use of the advanced features of Windows 3.11.
In this paper we describe an abstract model for the development of object-oriented software in a context where several programmers work together as a team. We introduce the different levels that compose our model, map...
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In this paper we describe an abstract model for the development of object-oriented software in a context where several programmers work together as a team. We introduce the different levels that compose our model, mapping its concepts and tools to existing systems whenever possible. The goal of this work is to design an environment for co-operative programming that deals specifically with the needs of developers using object-oriented technology. Our model is based on existing software engineering tools for the development of medium and large software projects, and also on a survey of user requirements for object-oriented programming. We explain the reasons why existing software engineering tools for team programming are not suited to object-oriented technology. We also briefly describe our prototype and the tools necessary to support our co-operative object-oriented programming model.
This paper presents a computer-aided planning system that is capable of generating assembly sequences for aircraft frame assemblies. The representation scheme for aircraft frame assemblies is first described. Algorith...
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This paper presents a computer-aided planning system that is capable of generating assembly sequences for aircraft frame assemblies. The representation scheme for aircraft frame assemblies is first described. Algorithms for the automated generation of assembly sequences are then discussed. The planning system takes assembly drawing and bill of material as inputs. In consideration of both the geometric and technical constraints in the planning stage, the system generates an assembly sequence as output. The system has been implemented using an object-oriented approach (C++) and a graphical user interface under MS-Windows. A spar subassembly is used to demonstrate the working of the methodology as well as the implemented system.
Alarm processing is a traditional feature of energy-management systems (EMS), and has not changed significantly over several generations of SCADA design. This paper describes two parts of a project between the Univers...
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Alarm processing is a traditional feature of energy-management systems (EMS), and has not changed significantly over several generations of SCADA design. This paper describes two parts of a project between the University of Dundee and Scottish Hydro-Electric pie (HE) on the use of an Artificial Intelligence system for alarm processing and fault diagnosis. The first part of the project was an overview and comparison study of three real-time object-oriented toolkits: Muse, Kappa and Nexpert object. The study is based on the capabilities of such toolkits to handle the power system alarm processing, integration with external programs and real-time databases, portability, price and execution speed. Some advantages and drawbacks of each toolkit are also pointed out. The second part of the project was the implementation of an object-oriented expert system using the KappaPC toolkit operating on a 486 IBM compatable PC under Microsoft Windows 3.1. The toolkit was chosen in the first part of the project, for the initial development of a prototype real-time alarm-processing and fault-diagnosis system. The structure of the object-oriented expert system captures the heuristic knowledge used for power system operation. The knowledge-base is automatically updated by the existing SCADA system as the power system's status changes. The paper also describes the features of the real-time object-oriented expert system;these include the need for fast, deep-level reasoning, easy maintainability of the object-oriented programming and the end user's interface.
While early knowledge-based systems suffered the frequent criticism of having little relevance to the real world, an increasing number of current applications deal with complex, real-world problems. Due to the complex...
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While early knowledge-based systems suffered the frequent criticism of having little relevance to the real world, an increasing number of current applications deal with complex, real-world problems. Due to the complexity of real-world situations, no one general software technique can produce adequate results in different problem domains, and artificial intelligence usually needs to be integrated with conventional paradigms for efficient solutions. The complexity and diversity of real-world applications have also forced the researchers in the AI field to focus more on the integration of diverse knowledge representation and reasoning techniques for solving challenging, real-world problems. Our development environment, BEST (Blackboard-based Expert Systems Toolkit), is aimed to provide the ability to produce large-scale, evolvable, heterogeneous intelligent systems. BEST incorporates the best of multiple programming paradigms in order to avoid restricting users to a single way of expressing either knowledge or data. It combines rule-based programming, object-oriented programming, logic programming, procedural programming and blackboard modelling in a single architecture for knowledge engineering, so that the user can tailor a style of programming to his application, using any or arbitrary combinations of methods to provide a complete solution. The deep integration of all these techniques yields a toolkit more effective even for a specific single application than any technique in isolation or collections of multiple techniques less fully integrated. Within the basic, knowledge-based programming paradigm, BEST offers a multiparadigm language for representing complex knowledge, including incomplete and uncertain knowledge. Its problem solving facilities include truth maintenance, inheritance over arbitrary relations, temporal and hypothetical reasoning, opportunistic control, automatic partitioning and scheduling, and both blackboard and distributed problem-solving paradi
We propose a novel formalism, called Frame Logic (abbr., F-logic), that accounts in a clean and declarative fashion for most of the structural aspects of object-oriented and frame-based languages. These features inclu...
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We propose a novel formalism, called Frame Logic (abbr., F-logic), that accounts in a clean and declarative fashion for most of the structural aspects of object-oriented and frame-based languages. These features include object identity, complex objects, inheritance, polymorphic types, query methods, encapsulation, and others. In a sense, F-logic stands in the same relationship to the object-oriented paradigm as classical predicate calculus stands to relational programming. F-logic has a model-theoretic semantics and a sound and complete resolution-based proof theory. A small number of fundamental concepts that come from object-oriented programming have direct representation in F-logic;other, secondary aspects of this paradigm are easily modeled as well. The paper also discusses semantic issues pertaining to programming with a deductive object-oriented language based on a subset of F-logic.
Inheritance, together with object and class, is the key concept of objectoriented systems. Adopting the concept-oriented view (COV for short) of inheritance, current OO systems such as GemStone, Orion, C++, O-2, Post...
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Inheritance, together with object and class, is the key concept of objectoriented systems. Adopting the concept-oriented view (COV for short) of inheritance, current OO systems such as GemStone, Orion, C++, O-2, PostGres, Iris, and SmallTalk dominantly interpret inheritance by retaining all attributes and methods in a subclass from its superclass, and by supporting the specification of additional attributes and methods in the subclass. However, this monotonic extension property may result in a redundant subclass representation which in turn gives rise to update anomalies. Thus extra effort in practice used to prevent these problems from happening is to change an IS-A relationship in COV of hierarchy into sibling in the program-oriented view (POV for short) hierarchy. However, the dichotomy between the concept and implementation leads to a significant difference of the class hierarchy between the designing phase and implementation phase of OO systems, hence increases the complexity in designing OO systems. In this paper, rye show that, when the subclass attributes are linearly related to the superclass attributes (the attributes in the superclass can be linearly expressed by those in the subclass), linear subclass assertions/constraints can be elegantly used to resolve the problems such as the redundant subclass representation, and update anomalies. We have proved that (1) given a linear subclass assertion, a non-redundant subclass representation can be automatically decided, and the bilateral mappings between the class and the determined subclass can be automatically constructed, and (2) given a user-chosen subclass representation and the mapping from the chosen subclass to the superclass, the linear subclass assertion and inverse mapping can be automatically constructed, and (3) placing an object into the most specific class in an ISA class hierarchy can be automatically conducted. The proposed novel ideas have been prototyped on GemStone/Smalltalk on a SunSparc/U
This paper presents a framework called logical knowledge object (LKO),which is taken as a basis of the dependable development of knowledge based systems(KBSs). LKO combines logic programming and object-oriented progra...
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This paper presents a framework called logical knowledge object (LKO),which is taken as a basis of the dependable development of knowledge based systems(KBSs). LKO combines logic programming and object-oriented programming paradigms, where objects are viewed as abstractions with states,constraints, behaviors and inheritance. The operational semantics defined in the style of natural semantics is simple and clear. A hybrid knowledge represen-tation amalgamating rule, frame, semantic network and blackboard is available for both most structured and flat knowledge. The management of knowledge bases has been formally specified. Accordingly, LKO is well suited for the formal representation of knowledge and requirements of KBSs. Based on the framework, verification techniques are also explored to enhance the analysis of requirement specifications and the validation of KBSs. In addition, LKO pro-vides a methodology for the development of KBSs, applying the concepts of rapid prototyping and top-down design to deal with changing and incomplete requirements, and to provide multiple abstract models of the domain, where formal methods might be used at each abstract level.
In order to support environmental scientists in finding an ''adequate'' model for the system they are investigating, a computer program is necessary that allows its users to perform simulations for dif...
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In order to support environmental scientists in finding an ''adequate'' model for the system they are investigating, a computer program is necessary that allows its users to perform simulations for different models, to assess the identifiability and to estimate the values of model parameters (using measured data), and to estimate prediction uncertainty. These requirements, especially that of providing much freedom in model formulation, are difficult to realize in such a program. In this paper, it is shown how object-oriented program design techniques were employed to facilitate the realization of an identification and simulation program for aquatic systems (AQUASIM) that is very flexible with regard to model formulation and that provides methods of sensitivity analysis, parameter estimation and uncertainty analysis in addition to simulation. It is the goal of this paper to encourage developers of environmental software to revise previously used program structures and to employ modern program design techniques.
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