Assessing the Role of Formal Specifications in Verification and Validation of Knowledge‑Based Systems

This paper examines how formal specification techniques can support the verification and validation (V&V) of knowledge-based systems. Formal specification techniques provide levels of description which support both verification and validation, and V&V techniques feed back to assist the development of the specifications. Developing a formal specification for a system requires the prior construction of a conceptual model for the intended system. Many elements of this conceptual model can be effectively used to support V&V. Using these elements, the V&V process becomes deeper and more elaborate and it produces results of a better quality compared with the V&V activities which can be performed on systems developed without conceptual models. However, we note that there are concerns in using formal specification techniques for V&V, not least being the effort involved in creating the specifications

A framework for managing global risk factors affecting construction cost performance

Poor cost performance of construction projects has been a major concern for both contractors and clients. The effective management of risk is thus critical to the success of any construction project and the importance of risk management has grown as projects have become more complex and competition has increased. Contractors have traditionally used financial mark-ups to cover the risk associated with construction projects but as competition increases and margins have become tighter they can no longer rely on this strategy and must improve their ability to manage risk. Furthermore, the construction industry has witnessed significant changes particularly in procurement methods with clients allocating greater risks to contractors. Evidence shows that there is a gap between existing risk management techniques and tools, mainly built on normative statistical decision theory, and their practical application by construction contractors. The main reason behind the lack of use is that risk decision making within construction organisations is heavily based upon experience, intuition and judgement and not on mathematical models. This thesis presents a model for managing global risk factors affecting construction cost performance of construction projects. The model has been developed using behavioural decision approach, fuzzy logic technology, and Artificial Intelligence technology. The methodology adopted to conduct the research involved a thorough literature survey on risk management, informal and formal discussions with construction practitioners to assess the extent of the problem, a questionnaire survey to evaluate the importance of global risk factors and, finally, repertory grid interviews aimed at eliciting relevant knowledge. There are several approaches to categorising risks permeating construction projects. This research groups risks into three main categories, namely organisation-specific, global and Acts of God. It focuses on global risk factors because they are ill-defined, less understood by contractors and difficult to model, assess and manage although they have huge impact on cost performance. Generally, contractors, especially in developing countries, have insufficient experience and knowledge to manage them effectively. The research identified the following groups of global risk factors as having significant impact on cost performance: estimator related, project related, fraudulent practices related, competition related, construction related, economy related and political related factors. The model was tested for validity through a panel of validators (experts) and crosssectional cases studies, and the general conclusion was that it could provide valuable assistance in the management of global risk factors since it is effective, efficient, flexible and user-friendly. The findings stress the need to depart from traditional approaches and to explore new directions in order to equip contractors with effective risk management tools

A HOLISTIC APPROACH TO COMPUTER INTEGRATED MANUFACTURING ARCHITECTURE AND SYSTEMS DESIGN

This work addresses the problem of finding an improved solution to Computer Integrated Manufacturing (ClM) Architecture and Systems Design. The current approaches are shown to be difficult to understand and use, over complex. In spite of their complexity of approach they lack comprehensiveness and omit many factors and dimensions considered essential for success in today's competitive and often global market place. A new approach to ClM Architecture and Systems Design is presented which offers a simpler, more flexible and more robust format for defining a particular ClM System within a general architectural framework. At the same time this new approach is designed to offer a comprehensive and holistic solution. The research work involved the investigation of current approaches and research and development initiatives focusing particularly on the CIM-OSA and GRAI Integrated methodologies in the field of ClM Architecture. The strengths and weaknesses of the various approaches are examined. Developments in other related fields including manufacturing systems, manufacturing management, information technology and systems generally have been investigated regarding their relevance and possible contribution to an improved solution. The author has built on his practical experience in creating, designing and managing the implementation of a global CIM system. The authors work on several publicly funded collaborative research and development projects relevant to the problem area is described. These include CIM-OSA, IMOCIM and TIQS projects. In the latter two projects the author was instrumental in developing the methodological approach based on a systems approach to business processes in connection with the design of quality and manufacturing systems. Both of these projects have contributed to this work. The author has also participated in the global IMS programme as a rapporteur for the European Commission and this helped to provide a global perspective on the problems of manufacturing companies as they attempt to compete in a world wide market place. The results of this work provide the basis for a radically improved approach to ClM Architecture and Systems Design based on the holistic view of an enterprise. The approach developed supports the business process view of an enterprise; addresses the people and organisational aspects; leads to ClM solutions focused on meeting enterprise goals; and is able to deal with a significantly increased scope and complexity compared with existing methods yet is easily understood and more simple to simple to apply than current approaches

Against the grain: the battle for public service broadcasting in Taiwan

Over the last two decades public service broadcasting (PSB) around the world has faced increasing pressures from accelerating commercialisation and the fragmentation of the broadcasting landscape. This has led a number of media commentators in the system’s traditional heartlands to ask whether the idea has now outlived its usefulness. Against the grain of this international trend, Taiwan has moved in the opposite direction, democratising its state-owned television system and introducing a form of public broadcasting for the first time. Against the grain of growing enthusiasm for a privatised solution supporters presented PSB as a necessary counter to the perceived deficiencies of the existing system, in serving a society moving from authoritarian to competitive party rule. This study sets out to explore how the expansion of PSB in Taiwan has been socially defined and constructed, and by whom. The various constructions in play were mapped through in-depth interviews with a range of claim-makers involved in the process. A systematic content analysis of the mainstream Taiwanese press was then conducted to explore the ways contending positions and issues were presented in the public domain and to identify the key voices given a public platform. This analysis demonstrated that the opinions and concerns of the general public were largely missing from a debate dominated by political and academic elites. Against the grain of their own claims to be representing the public key actors constructed public debate as a series of monologues, advancing their own sectional and paternalistic interpretations of the public interest. These findings point to the supremely ironic conclusion that a process ostensibly dedicated to reconstructing broadcasting as key element in a new, democratic, public sphere, excluded the public from active participation and relegated them to the role of spectators

A knowledge-based approach for the extraction of machining features from solid models

Computer understanding of machining features such as holes and pockets is essential for bridging the communication gap between Computer Aided Design and Computer Aided Manufacture. This thesis describes a prototype machining feature extraction system that is implemented by integrating the VAX-OPS5 rule-based artificial intelligence environment with the PADL-2 solid modeller. Specification of original stock and finished part geometry within the solid modeller is followed by determination of the nominal surface boundary of the corresponding cavity volume model by means of Boolean subtraction and boundary evaluation. The boundary model of the cavity volume is managed by using winged-edge and frame-based data structures. Machining features are extracted using two methods : (1) automatic feature recognition, and (2) machine learning of features for subsequent recognition. [Continues.