A methodology for integrating legacy systems with the client/server environment

The research is conducted in the area of software methodologies with the emphasis on the integration of legacy systems with the client/server environment. The investigation starts with identifying the characteristics of legacy systems in order to determine the features and technical characteristics required of an integration methodology. A number of existing methodologies are evaluated with respect to their features and technical characteristics in order to derive a synthesis for a generic methodology. This evaluation yields the meta primitives of a generic methodology. The revised spiral model (Boehm,1986; DuPlessis & Vander Wah,1992) is customised to arrive at a software process model which provides a framework for the integration of legacy systems with the client/server environment. The integration methodology is based on this process model.ComputingM. Sc. (Information Systems

Defining the mechanisms of a cooperative computer system based on theories of cooperation

There is a growing interest in the development of computer systems that are actively involved in the tasks of the users and serve to augment the users' creativity. Cooperative computing is a major contribution to this research field. A survey of current developments in knowledge based systems led to the conclusion that there has hitherto been an absence of a formal definition of the mechanisms of cooperative computer systems based on theories of cooperation. The work in this thesis seeks to provide a full definition of cooperation derived from the behaviours of living cooperative systems. Studies on human cooperation and cooperation in the animal kingdom, established that cooperation is a dynamic behaviour; in that the interaction processes between the cooperative partners serve to facilitate the achievement of a common goal, or a set of goals that are mutually desired by the partners. Partners in cooperation are interdependent: one member's actions are contingent on another. Therefore, the underlying processes which induce and maintain cooperation were identified. These are: communication between the partners; emergence of norms and roles governing the behaviour of the cooperating members; resolution of conflicts; distributed and coordinated activities. These factors were further elucidated within the context of small problem solving groups. A model of cooperationw hich encapsulatedth esef actors was produced. From the discussionso f the advantageso f cooperationw ithin different contexts, the potential for synergy was found to be the main benefit of cooperation. The potential for achieving this synergy between a human and a computer is the main motivation for the work undertaken in this research. From the theoretical analysis of cooperation, the underlying mechanisms of a cooperative computer were successfully defined. A conceptual model of human-computer cooperation was presented. It was established that the quality of cooperation is closely associated with the nature of the task. Therefore, it is not practicable to produce a general purpose cooperative system. A specific task must be used. Creative tasks of a problem identifying and solving nature, were found to be more suitable to cooperative behaviour than others. Typical of these, and the one selected, was computer screen design. Current screen design practice was analysed, and the functional requirements and knowledge base needs of the systems were established. The underlying mechanisms of cooperation were formalised and successfully implemented within a software exemplar, named COSY. COSY exhibits the behavioural characteristics of cooperation, and utilises the knowledge of screen design to support users in the task of formatting computer screens. COSY successfully demonstrated the synergistic relationship in its cooperation with the users. It is concluded that the approach undertaken in this thesis has lead to a successful definition and implementation of the formal mechanisms of cooperation in a computer system, one which potentially enhances the innovative and creative aspects of design work

The Sixth Annual Workshop on Space Operations Applications and Research (SOAR 1992)

This document contains papers presented at the Space Operations, Applications, and Research Symposium (SOAR) hosted by the U.S. Air Force (USAF) on 4-6 Aug. 1992 and held at the JSC Gilruth Recreation Center. The symposium was cosponsored by the Air Force Material Command and by NASA/JSC. Key technical areas covered during the symposium were robotic and telepresence, automation and intelligent systems, human factors, life sciences, and space maintenance and servicing. The SOAR differed from most other conferences in that it was concerned with Government-sponsored research and development relevant to aerospace operations. The symposium's proceedings include papers covering various disciplines presented by experts from NASA, the USAF, universities, and industry

Testing a Model of School Holding Power: Teacher Perceptions of the Work Environment, Robustness, Personal Characteristics, and Alienation Behavior. (Volumes I and II).

The purpose of the study was to examine relationships between indices of teacher alienation behavior (TAB) and (a) teacher perceptions of multiple dimensions of the work environment, (b) environmental robustness, and (c) teacher personal life characteristics. Teacher perceptions of the work environment and the robustness of key roles in the school organization were explored as factors contributing to the holding power of school. Twenty teachers at each of 97 schools in a large urban school district in Louisiana were randomly selected. Each teacher responded to an instrument set containing a demographic data form, Job Satisfaction Scale (JSS) (Johnson, 1955), Robustness Semantic Differential (RSD) (Willower and Licata, 1978), and Teacher Life Characteristics Index (TLCI) (developed for this study). Teacher-related data (number of sick days, number of professional leave days, number of teachers on sabbatical leave, and teacher turnover) and student-related variables (student achievement data, student attendance data, student retention rates, and SES data) were collected by school. Extrinsic factor analyses were completed to shorten and revise the JSS and a series of correlations were computed to test the research hypotheses. Correlations between TAB and (a) JSS, (b) RSD, and (c) TLCI were low and nonsignificant. The correlation between student achievement data and the JSS subscale Perceptions of the Job was negative, low, and nonsignificant. Correlations between RSD concepts and student achievement and between RSD concepts and student attendance were positive, moderate, and statistically significant. Correlations between RSD concepts and student retention rates were negative, low, and statistically significant. The major implications of the study were (a) the JSS is a three-subscale instrument rather than a nine-subscale instrument; (b) the JSS and the RSD as indices of school holding power were more strongly related to student-related variables than to teacher-related variables; (c) positive teacher perceptions of the environment may reach a satiation level reflecting complacency in low achieving schools; and (d) increasing the environmental robustness may increase the holding power of schools and result in increased attendance and student achievement and decreased student retention rates. Implications of the findings for future research and theory development were discussed

Estimating the effort in the early stages of software development.

Estimates of the costs involved in the development of a software product and the likely risk are two of the main components associated with the evaluation of software projects and their approval for development. They are essential before the development starts, since the investment early in software development determines the overall cost of the system. When making these estimates, however, the unknown obscures the known and high uncertainty is embedded in the process. This is the essence of the estimator's dilemma and the concerns of this thesis. This thesis offers an Effort Estimation Model (EEM), a support system to assist the process of project evaluation early in the development, when the project is about to start. The estimates are based on preliminary data and on the judgement of the estimators. They are developed for the early stages of software building in which the requirements are defined and the gross design of the software product is specified. From these estimates only coarse estimates of the total development effort are feasible. These coarse estimates are updated when uncertainty is reduced. The basic element common to all frameworks for software building is the activity. Thus the EEM uses a knowledge-base which includes decomposition of the software development process into the activity level. Components which contribute to the effort associated with the activities implemented early in the development process are identified. They are the size metrics used by the EEM. The data incorporated in the knowledge-base for each activity, and the rules for the assessment of the complexity and risk perceived in the development, allow the estimation process to take place. They form the infrastructure for a 'process model' for effort estimating. The process of estimating the effort and of developing the software are linked. Assumptions taken throughout the process are recorded and assist in understanding deviations between estimates and actual effort and enable the incorporation of a feedback mechanism into the process of software development. These estimates support the decision process associated with the overall management of software development, they facilitate management involvement and are thus considered as critical success factors for the management of software projects

Prediction of Object Position based on Probabilistic Qualitative Spatial Relations

Due to recent and extensive advancements in the robotic and artificial intelligence fields, intelligent systems can be found, with increasing frequency, in many areas of daily life. From industrial and surgical purposes to space robots, such complex systems are present. However, as demands for robotics systems increase, sophisticated algorithms for use in robotic areas such as perception, navigation, or manipulation are required. Although some algorithms for such purposes exist, there are still open questions and challenges that must be addressed. Although robots are primarily used in the manufacturing industry, which has since been revolutionized by their precision and speed, there is a growing trend towards using service and personal robotics applications. The latter in particular must interact with humans naturally and effectively manage their environments, such as offices and homes. In contrast to the systems used in an industrial context, systems such as personal robots do not act in a predefined and fixed environment. Rather, these intelligent systems need an intrinsic comprehension of human environments to be able to support people in their daily life and manage common tasks such as preparing a breakfast table or cleaning a room. Crucially, these new robot systems require an entirely new level of capabilities to act in dynamic human environments. This thesis addresses how qualitative spatial relations can be used to find an objecta s most probable location and thus guide the search for a sought object. Because current approaches focus mainly on crisp, two-dimensional relations, which are not directly suitable for use in three-dimensional real-world applications, a formalism for a new type of spatial relations is proposed in this work. This theoretical approach is then applied on real-world data to evaluate its applicability for robotics purposes. The resulting validation of the approach demonstrates that the developed method performs well and can be used to enhance search for objects

Statistical analysis of television audience measurement systems and their implications.

This thesis focuses on the identification of measurement errors in television audience measurement systems and their implications to the television industry. BARB in the UK and Mediamat in France are the case studies selected. Measurement errors are identified by assessing the sampling and non sampling operations implemented in these sample surveys but also by integrating the uses that are made of the estimates yielded and the meaning of the concept measured. The thesis argues that the commodities traded on the television market are not audiences but statistics: namely, television ratings, and that this commodity production function is a distinctive feature of these sample surveys. The means by which these commodities are produced by broadcasters, and priced and bought by agencies on behalf of advertisers are examined. It is shown that prices attached by buyers to these commodities rely on factors that are grounded in economic rather than statistical considerations, and that the commodities are not known at the moment they are priced but need to be projected. It is argued that television audience measurement systems are based on a construct of the audience that relies entirely on assumptions and operational definitions. The consequences of this approach to measurement on the uses to which the data are currently put and on the capacity of the industry for making predictions are examined. It is suggested that the data collection technique implemented in these measurement systems is of decisive importance to the sampling design and the economy of the medium. The validity of the people-metering data collection technique currently in use is assessed. It is argued that this technique imposes the use of samples that are not valid from a statistical viewpoint. Components of variance for audience estimates are identified and a method for searching for patterns in standard errors for audience estimates is proposed. The implications of the findings in the new television environment are developed