A Bayesian formulation of search, control and the exploration/exploitation trade-off

A new approach to optimisation is introduced based on a precise probabilistic statement of what is ideally required of an optimisation method. It is convenient to express the formalism in terms of the control of a stationary environment. This leads to an objective function for the controller which unifies the objectives of exploration and exploitation, thereby providing a quantitative principle for managing this trade-off. This is demonstrated using a variant of the multi-armed bandit problem. This approach opens new possibilities for optimisation algorithms, particularly by using neural network or other adaptive methods for the adaptive controller. It also opens possibilities for deepening understanding of existing methods. The realisation of these possibilities requires research into practical approximations of the exact formalism.

Technology sourcing versus technology exploitation:An analysis of US foreign direct investment flows

The traditional paradigm of foreign direct investment (FDI) suggests that FDI is undertaken principally to exploit some firm-specific advantage in a foreign country which provides a locational advantage to the investor. However, recent theoretical work suggests a model of FDI in which the motivation is not to exploit existing technological advantages in a foreign country, but to access such technology and transfer it from the host economy to the investing multinational corporation via spillover effects. This paper tests the technology sourcing versus technology exploiting hypotheses for a panel of sectoral FDI flows between the United States and major OECD nations over a 15 year period. The research makes use of Patel and Vega's (Research Policy, 28, 145-55, 1999) taxonomy of sectors which are likely a priori to exhibit technology sourcing and exploiting behaviour respectively. While there is evidence that FDI flows into the United States are attracted to R and D intensive sectors, very little support is found for the technology sourcing hypothesis either for inward or outward FDI flows. The results suggest that, in aggregate, firm-specific 'ownership' effects remain powerful determinants of FDI flows.

Dispersion managed soliton systems

Dispersion managed solitons have been discovered to have some remarkable properties which indicate an outstanding opportunity for exploitation in transmission systems. This paper will review and interpret these discoveries and discuss the potential for WDM of these solitons for both long distance systems and for the upgrade of the installed fibre base.

Exploitation of fibre characteristics in temperature sensing and radio-over-fibre applications

The development of sensing devices is one of the instrumentation fields that has grown rapidly in the last decade. Corresponding to the swift advance in the development of microelectronic sensors, optical fibre sensors are widely investigated because of their advantageous properties over the electronics sensors such as their wavelength multiplexing capability and high sensitivity to temperature, pressure, strain, vibration and acoustic emission. Moreover, optical fibre sensors are more attractive than the electronics sensors as they can perform distributed sensing, in terms of covering a reasonably large area using a single piece of fibre. Apart from being a responsive element in the sensing field, optical fibre possesses good assets in generating, distributing, processing and transmitting signals in the future broadband information network. These assets include wide bandwidth, high capacity and low loss that grant mobility and flexibility for wireless access systems. Among these core technologies, the fibre optic signal processing and transmission of optical and radio frequency signals have been the subjects of study in this thesis. Based on the intrinsic properties of single-mode optical fibre, this thesis aims to exploit the fibre characteristics such as thermal sensitivity, birefringence, dispersion and nonlinearity, in the applications of temperature sensing and radio-over-fibre systems. By exploiting the fibre thermal sensitivity, a fully distributed temperature sensing system consisting of an apodised chirped fibre Bragg grating has been implemented. The proposed system has proven to be efficient in characterising grating and providing the information of temperature variation, location and width of the heat source applied in the area under test.To exploit the fibre birefringence, a fibre delay line filter using a single high-birefringence optical fibre structure has been presented. The proposed filter can be reconfigured and programmed by adjusting the input azimuth of launched light, as well as the strength and direction of the applied coupling, to meet the requirements of signal processing for different purposes in microwave photonic and optical filtering applications. To exploit the fibre dispersion and nonlinearity, experimental investigations have been carried out to study their joint effect in high power double-sideband and single-sideband modulated links with the presence of fibre loss. The experimental results have been theoretically verified based on the in-house implementation of the split-step Fourier method applied to the generalised nonlinear Schrödinger equation. Further simulation study on the inter-modulation distortion in two-tone signal transmission has also been presented so as to show the effect of nonlinearity of one channel on the other. In addition to the experimental work, numerical simulations have also been carried out in all the proposed systems, to ensure that all the aspects concerned are comprehensively investigated.

Returned medicines:Waste or a wasted opportunity?

Background: Re-use of unused medicines returned from patients is currently considered unethical in the UK and these are usually destroyed by incineration. Previous studies suggest that many of these medicines may be in a condition suitable for re-use. Methods: All medicines returned over two months to participating community pharmacies and GP surgeries in Eastern Birmingham PCT were assessed for type, quantity and value. A registered pharmacist assessed packs against set criteria to determine the suitability for possible re-use. Results: Nine hundred and thirty-four return events were made from 910 patients, comprising 3765 items worth £33 608. Cardiovascular drugs (1003, 27%) and those acting on the CNS (884, 24%) were most prevalent. Returned packs had a median of 17 months remaining before expiry and one-quarter of packs (1248 out of 4291) were suitable for possible re-use. One-third of those suitable for re-use (476 out of 1248) contained drugs in the latest WHO Essential Drugs List. Conclusion: Unused medicines are returned in substantial quantities and have considerable financial value, with many in a condition suitable for re-use. We consider it appropriate to reopen the debate on the potential for re-using these medicines in developing countries where medicines are not widely available and also within the UK. © The Author 2007, Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved.

Exploitation of multilayer coatings for infrared surface plasmon resonance fiber sensors

We demonstrate surface plasmon resonance (SPR) fiber devices based upon ultraviolet inscription of a grating-type structure into both single-layered and multilayered thin films deposited on the flat side of a lapped D-shaped fiber. The single-layered devices were fabricated from germanium, while the multilayered ones comprised layers of germanium, silica, and silver. Some of the devices operated in air with high coupling efficiency in excess of 40 dB and an estimated index sensitivity of Delta lambda/Delta n = 90 mn from 1 to 1.15 index range, while others provided an index sensitivity of Delta lambda/Delta n = 6790 mn for refractive indices from 1.33 to 1.37. (C) 2009 Optical Society of America

The influence of political, economic and passenger market factors on international civil aviation

Civil aviation plays an essential role in maintaining international communications. Many extraneous factors influence the daily operations of the air transport industry. This thesis begins by investigating the major categories of so­ called "external interests" in civil aviation. These are shown to have played a significant part in ensuring the need for international agreement over the adoption of regulating principles. The combination and interaction of the various influences has produced a particular type of regulatory environment in which all commercial air services have to operate. The need for such regulation and the extreme difficulty experienced in trying to define universally acceptable methods of supervision is discussed. It is shown how opportunity for the development of on-scheduled air services was created by default on the part of the European Governments.The concept of so-called "scheduled" and "non-scheduled" sectors" is considered and it is suggested that growth of the inclusive tour industry resulted from inappropriate categorisation of the air services involved. The means by which development opportunities were created for inclusive tour operations is considered and the work then investigates the importance of British air transport policy in their exploitation. The politics of British civil aviation in the post-war years is the subject of detailed examination and the process by which Independent airlines were encouraged to develop inclusive tours, is identified. This theme is expanded to demonstrate the vital contribution of British air transport policy in the restructuring of the international industry. The subsequent involvement of the United States is shown to have been directed specifically towards the satisfaction of domestic issues. British objectives, however, are considered to have been more generally concerned with improving the tariff structure. The unique opportunities for British experimentation with international fares are seen to have major influence in forcing the pace of tariff rationalisation.

An opportunity for system dynamics in manufacturing system modelling

The computer simulation of manufacturing systems is commonly carried out using discrete event simulation (DES). Indeed, there appears to be a lack of applications of continuous simulation methods, particularly system dynamics (SD), despite evidence that this technique is suitable for industrial modelling. This paper investigates whether this is due to a decline in the general popularity of SD, or whether modelling of manufacturing systems represents a missed opportunity for SD. On this basis, the paper first gives a review of the concept of SD and fully describes the modelling technique. Following on, a survey of the published applications of SD in the 1990s is made by developing and using a structured classification approach. From this review, observations are made about the application of the SD method and opportunities for future research are suggested.

Shaping strategic action through the rhetorical construction and exploitation of ambiguity

This paper extends existing understandings of how actors' constructions of ambiguity shape the emergent process of strategic action. We theoretically elaborate the role of rhetoric in exploiting strategic ambiguity, based on analysis of a longitudinal case study of an internationalization strategy within a business school. Our data show that actors use rhetoric to construct three types of strategic ambiguity: protective ambiguity that appeals to common values in order to protect particular interests, invitational ambiguity that appeals to common values in order to invite participation in particular actions, and adaptive ambiguity that enables the temporary adoption of specific values in order to appeal to a particular audience at one point in time. These rhetorical constructions of ambiguity follow a processual pattern that shapes the emergent process of strategic action. Our findings show that (1) the strategic actions that emerge are shaped by the way actors construct and exploit ambiguity, (2) the ambiguity intrinsic to the action is analytically distinct from ambiguity that is constructed and exploited by actors, and (3) ambiguity construction shifts over time to accommodate the emerging pattern of actions.

Opportunity, fair process and relationship value:career development as a driver of proactive work behaviour

In line with recent findings from organisational justice theory, we hypothesised that employee proactive behaviour and careerist orientation is predicted by the interplay of perceived favourability of career development opportunities, the perceived fairness of the procedures used to decide them, and employee organisational commitment. Employees (N = 325) of a large financial services organisation responded to a self-completion questionnaire. As predicted, when career development opportunities were viewed unfavourably, perceived procedural justice was significantly and positively related to individual proactive behaviour and significantly and negatively related to careerist orientation but only when organisational commitment was high. It appears that high procedural justice may only 'offset' the negative effects of unfavourable career development opportunities when employees identify with, and are committed to, their organisation. Further support is presented for a relational, rather than instrumental, model of procedural justice when reflecting on employee reactions to their employers' policies and decision-making. Implications for theory and practice are discussed.

Dynamic client portfolios as sources of ambidexterity:exploration and exploitation within and across client relationships

This paper explains how dynamic client portfolios can be a source of ambidexterity (i.e., exploration and exploitation) for knowledge-intensive firms (KIFs). Drawing from a unique qualitative dataset of firms in the global reinsurance market, we show how different types of client relationships underpin a dynamic client portfolio and become a source of ambidexterity for a KIF. We develop a process model to show how KIFs attain knowledge by segmenting their client portfolios, use that knowledge to explore and exploit within and across their client relationships, and dynamically adjust their client portfolios over time. Our study contributes to the literature on external sources of ambidexterity and dynamic management of client knowledge within KIFs.

An alternative measure of the ICT-Opportunity Index

We developed an alternative approach for measuring information and communication technology (ICT), applying Data Envelopment Analysis (DEA) using data from the International Telecommunications Union as a sample of 183 economies. We compared the ICT-Opportunity Index (ICT-OI) with our DEA-Opportunity Index (DEA-OI) and found a high correlation between the two. Our findings suggest that both indices are consistent in their measurement of digital opportunity, though differences still exist in different regions. Our new DEA-OI offers much more than the ICT-OI. Using our model, the target and peer groups for each country can be identified.