City University London

About: City University London is a education organization based out in London, United Kingdom. It is known for research contribution in the topics: Population & Health care. The organization has 5735 authors who have published 17285 publications receiving 453290 citations.

Exploiting reusable specifications through analogy

Abstract: domain model representing critical determinants of the theater reservation/course administration analogy Objects in Objects in space space Monitor objects whenever one moves Cancelled allocations System should monitor object spaces to ensure only one object in any space Abstract domain model representing critical determinants of the air traffic control/flexible manufacturing analogydomain model representing critical determinants of the air traffic control/flexible manufacturing analogy FigUre 3. Abstract domain models representing critical determinants of the two example analogies. frequent mistake made by the relatively inexperienced software engineers in this study was to focus on surface, lexical properties of the reusable specification, whereas successful reuse requires comprehension of deeper analogous concepts. Analogies represented in abstract form proved easier to recognize, although once recognized, reuse of concrete specifications proved more effective. Reuse of concrete specifications supported by abstraction during analogical recognition is one scenario which may lead to effective specification

Cash Flows in Networks

Abstract: The concept of maximising present value is applied to the timing of activities in a network. The mathematical form of the problem is that of maximising a nonlinear function subject to linear constraints and can be solved as a succession of linear programmes. By application of duality principles the problem can be treated as a form of maximum value flow problem in which discounted cash flows are distributed along arcs from pay events to receipt events. The solution is aided by the “equilibrium theorem” of dual linear programming in that in the optimum condition flows occur only along arcs whose corresponding activity has zero float. The flows which occur in the optimally scheduled solution are directly proportional to the marginal cost which would be incurred by lengthening the activity corresponding to the arc along which the flow occurs. Some implications derived from the model are discussed and a number of possible applications are proposed.

The Free Rider Problem and a Social Custom Model of Trade Union Membership

Abstract: The literature on public good provision by groups has traditionally emphasized the free rider problem. If it is assumed that a group forms to provide, or to lobby for the provision of, a good that is collective to potential members, then the major conceptual problem to the formation of such a group is that individuals can enjoy the benefits of group action without incurring the costs. By doing this, they free ride. In small groups the free rider problem is not generally considered insurmountable. However, the larger the number of potential beneficiaries, the more difficult it is to overcome the free rider problem, due to exclusion and surveillance difficulties, and the less likely is optimal collective good provision, or any collective good provision in the extreme. The free rider hypothesis has a long history in economic thought. As early as 1848, the free rider potential of any group of workers was perceived by J. S. Mill. However, it appears that it was not until 1965 that an attempt was made to explain why large groups providing collective goods manage to exist despite the free rider problem. Olson [1965] proposed the following explanation. If a large group exists, it must have formed either because membership is compulsory or because the group provides private goods and services accessible only to its members, with ancillary provision of the collective good as a "byproduct." The literature that developed from Olson's work has focused primarily on the suboptimal provision of the collective good, the difficulties of getting members to contribute in proportion to the benefits received, and preference revelation incentives. (See for example Groves and Ledyard [1977].) However, there are problems with both of the solutions proposed by Olson to overcome the free rider problem facing large groups. First, if coercion is looked at as a solution to the free rider problem, the question arises as to how the coercion itself is financed [Guttman, 1978]. This is unlikely to be costless. The second problem concerns the "byproduct" solution. Private good pro-

Field-Configuring Events as Structuring Mechanisms: How Conferences, Ceremonies, and Trade Shows Constitute New Technologies, Industries, and Marketsguest Editors Introduction

Abstract: In this introductory article to the Special Issue we make a case for the study of field-configuring events (FCEs). We begin with a discussion of the nature and character of FCEs. We next situate the study of FCEs in the context of ongoing research addressing the growth and evolution of institutional, organizational, and professional fields. We follow this with an overview of the relationship between FCEs and the evolution of fields, paying particular attention to how FCEs link field evolution at the macro level with individual action at the micro level. We then examine the unique methodological advantages that the study of FCEs offers to researchers who are interested in studying dynamic field processes. We conclude with a summary of the five papers that make up this Special Issue.

Stock Market Linkages in Emerging Markets: Implications for International Portfolio Diversification

Abstract: This paper examines stock market linkages of a group of Pacific-Basin countries with U.S. and Japan by estimating the multivariate cointegration model in both the autoregressive and moving average forms over the period 1980-1998. Recursive estimation helps identify the evolution of the linkages. The results for the 1980s indicate that the relaxation of foreign ownership restrictions was not sufficient to attract foreign investors' attention and that other factors must have affected the portfolio diversification decision. The results of the 1990s suggest that the relaxation of the restrictions might have strengthened international market interrelations. Country Funds have provided access to highly regulated capital markets.