http://www.dspace.cam.ac.uk:80/handle/1810/223849 Wed, 19 Jun 2013 23:48:16 GMT 2013-06-19T23:48:16Z http://www.dspace.cam.ac.uk:80/handle/1810/243402 Title: Brownian motion and multidimensional decision making Authors: Lange, Rutger-Jan Abstract: This thesis consists of three self-contained parts, each with its own abstract, body, references and page numbering. Part I, "Potential theory, path integrals and the Laplacian of the indicator", finds the transition density of absorbed or reflected Brownian motion in a d-dimensional domain as a Feynman-Kac functional involving the Laplacian of the indicator, thereby relating the hitherto unrelated fields of classical potential theory and path integrals. Part II, "The problem of alternatives", considers parallel investment in alternative technologies or drugs developed over time, where there can be only one winner. Parallel investment accelerates the search for the winner, and increases the winner's expected performance, but is also costly. To determine which candidates show sufficient performance and/or promise, we find an integral equation for the boundary of the optimal continuation region. Part III, "Optimal support for renewable deployment", considers the role of government subsidies for renewable technologies. Rapidly diminishing subsidies are cheaper for taxpayers, but could prematurely kill otherwise successful technologies. By contrast, high subsidies are not only expensive but can also prop up uneconomical technologies. To analyse this trade-off we present a new model for technology learning that makes capacity expansion endogenous. There are two reasons for this standalone structure. First, the target readership is divergent. Part I concerns mathematical physics, Part II operations research, and Part III policy. Readers interested in specific parts can thus read these in isolation. Those interested in the thesis as a whole may prefer to read the three introductions first. Second, the separate parts are only partially interconnected. Each uses some theory from the preceding part, but not all of it; e.g. Part II uses only a subset of the theory from Part I. The quickest route to Part III is therefore not through the entirety of the preceding parts. Furthermore, those instances where results from previous parts are used are clearly indicated. Mon, 07 May 2012 23:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243402 2012-05-07T23:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/240611 Title: Stochastic hub and spoke networks Authors: Hult, Edward Eric Abstract: Transportation systems such as mail, freight, passenger and even telecommunication systems most often employ a hub and spoke network structure since correctly designed they give a strong balance between high service quality and low costs resulting in an economically competitive operation. In addition, consumers are increasingly demanding fast and reliable transportation services, with services such as next day deliveries and fast business and pleasure trips becoming highly sought after. This makes finding an efficient design of a hub and spoke network of the utmost importance for any competing transportation company. However real life situations are complicated, dynamic and often require responses to many different fixed and random events. Therefore modeling the question of what is an optimal hub and spoke network structure and finding an optimal solution is very difficult. Due to this, many researchers and practitioners alike make several assumptions and simplifications on the behavior of such systems to allow mathematical models to be formulated and solved optimally or near optimally within a practical timeframe. Some assumptions and simplifications can however result in practically poor network design solutions being found. This thesis contributes to the research of hub and spoke networks by introducing new stochastic models and fast solution algorithms to help bridge the gap between theoretical solutions and designs that are useful in practice. Three main contributions are made in the thesis. First, in Chapter 2, a new formulation and solution algorithms are proposed to find exact solutions to a stochastic p-hub center problem. The stochastic p-hub center problem is about finding a network structure, where travel times on links are stochastic, which minimizes the longest path in the network to give fast delivery guarantees which will hold for some given probability. Second, in Chapter 3, the stochastic p-hub center problem is looked at using a new methodological approach which gives more realistic solutions to the network structures when applied to real life situations. In addition a new service model is proposed where volume of flow is also accounted for when considering the stochastic nature of travel times on links. Third, in Chapter 4, stochastic volume is considered to account for capacity constraints at hubs and, de facto, reduce the costs embedded in excessive hub volumes. Numerical experiments and results are conducted and reported for all models in all chapters which demonstrate the efficiency of the new proposed approaches. Mon, 10 Oct 2011 23:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/240611 2011-10-10T23:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/240608 Title: Practice, power and learning in UK recorded music companies Authors: Colbourne, Rick Abstract: This thesis adopts a practice-based approach to understanding how power, knowledge and knowing intermingle in organizations to facilitate/constrain individual access to opportunities for knowing-in-practice (learning). It explores how organizational mechanisms and technologies of regulation (re)construct and (re)produce organizational dimensions of knowledge as power/knowledge resources by which intermingling modalities of power are enacted to continuously sanction and (re)constitute individual meanings and identities. Mon, 10 Oct 2011 23:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/240608 2011-10-10T23:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/229514 Title: Morale: definitions, dimensions and measurement Authors: Hardy, Ben Abstract: Morale is a commonly used term both in business and society but the concept of morale is relatively poorly defined and understood. In a recent paper Liefooghe et al. (2004) expressed surprise that ‘…when reviewing the literature, no strong theory to explain morale as such is in evidence, nor are there many empirical studies that offer solid ground to advise organisations…’(p 1). This thesis aims to provide these theories and this empirical evidence in order to produce a better understanding of morale. This research identifies a number of deficiencies in the current understanding of morale. These range from elision with other concepts to disagreement about whether it is an individual or group phenomenon. In this study, four principal domains are examined: (i) what morale is; (ii) how it differs from other concepts; (iii) the antecedents of morale and (iv) its consequences. A mixed methods approach was adopted combining idiographic and nomothetic research. The idiographic phase of the research adopted a Straussian (1998) grounded theory approach, involving data collection from seven different organisations. The data was accrued from a combination of site visits, informal contacts, external research, and 203 semi-structured interviews which were supplemented with psychometric instruments. The data were then coded and analysed. Morale could be readily differentiated from other concepts and emerged as a phenomenon with three dimensions: affective, future/goal and interpersonal. It was also viewed as a single phenomenon which was generalisable across situations and rooted in the individual although perceived members of the group exerted considerable influence. The antecedents of morale impacted on the three dimensions outlined above. Its consequences were the zeal with which tasks are undertaken, creativity and engagement. The nomothetic element of the research developed a number of measurement scales, grounded in the qualitative phase. These allowed morale to be differentiated from other phenomena and offered insights into individual and group perceptions of morale and the influence of personality variables. Further quantitative research confirmed the three dimensional structure of the concept. The results of these two phases were then integrated to provide a picture of the phenomenon of morale, differentiate it from other concepts and elucidate its antecedents and consequences. An appraisal of the limitations of the research is also made. Finally the implications of this research for both academic researchers and practitioners are discussed along with suggestions for future research. Mon, 12 Apr 2010 23:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/229514 2010-04-12T23:00:00Z