Analytical first order comparison of amplitude and phase noise in single and dual Mach-Zehnder interferometer detection schemes for DQPSK transmission systems

An analytical first order calculation of the impact of Gaussian white noise on a novel single Mach-Zehnder Interferometer demodulation scheme for DQPSK reveals a constant Q factor ratio to the conventional scheme.

An Investigation into the adoption and implementation of computer aided production management systems:using the Rogers model of adoption and implementation and a social constuctionist account of technology

The research investigates the processes of adoption and implementation, by organisations, of computer aided production management systems (CAPM). It is organised around two different theoretical perspectives. The first part is informed by the Rogers model of the diffusion, adoption and implementation of innovations, and the second part by a social constructionist approach to technology. Rogers' work is critically evaluated and a model of adoption and implementation is distilled from it and applied to a set of empirical case studies. In the light of the case study data, strengths and weaknesses of the model are identified. It is argued that the model is too rational and linear to provide an adequate explanation of adoption processes. It is useful for understanding processes of implementation but requires further development. The model is not able to adequately encompass complex computer based technologies. However, the idea of 'reinvention' is identified as Roger's key concept but it needs to be conceptually extended. Both Roger's model and definition of CAPM found in the literature from production engineering tend to treat CAPM in objectivist terms. The problems with this view are addressed through a review of the literature on the sociology of technology, and it is argued that a social constructionist approach offers a more useful framework for understanding CAPM, its nature, adoption, implementation, and use. CAPM it is argued, must be understood on terms of the ways in which it is constituted in discourse, as part of a 'struggle for meaning' on the part of academics, professional engineers, suppliers, and users.

The effect of haem limitation and iron restriction on outer membrane proteins and on respiratory systems of non typable Haemophilus influenzae

The effects of haem limitation and iron restriction on cells of non typable Haemophilus influenzae were investigated. Haem limitation was achieved by adding concentrations of haem to growth media which resulted in substantial decreases in final cell yields. Iron restriction was achieved by substituting protoporphyrin IX (PPIX) for haem in the growth medium and adding an iron chelator to the system. The effect of these nutrient limitations on a) outer membrane composition, and b) respiratory systems of non typable H.influenzae was investigated. Several of the strains examined produced new PPIX-specific outer membrane proteins when cultured utilising PPIX as a porphyrin source. The immune response of patients with bronchiectasis to outer membrane antigens of H.influenzae cultured under iron-restricted conditions was analysed by ELISA and immunoblotting techniques. ELISA analysis revealed that individuals with severe bronchiectasis had high titres of antibodies directed against H.influenzae OMs in both serum and sputum. Immunoblotting with homologous serum showed that where PPIX-specific OMPs were produced they were antigenic and were recognised by patients' serum. This suggested that these H.influenzae OMPs may be expressed in vivo. Additionally, the development of the immune responses to non typable H.influenzae outer membrane antigens was investigated using a rat lung model. Bacteria encased in agar beads were inoculated intratracheally into rat lungs, infection was established, and the immune response monitored for 6 weeks. The animals developed antibodies to PPIX-specific OMPs during the course of infection, providing further evidence that H.influenzae express these novel OMP antigens when growing in vivo. Studies in vitro on respiratory systems of phenotypically altered H.influenzae showed that bacteria grown utilising PPIX as a porphyrin source, or under conditions of iron-restriction produced ten fold fewer cytochromes than cells grown in nutrient excess, while haem limited H.influenzae produced no detectable cytochromes. Respiration of various substrates was depressed in haem limited and in PPIX-grown cultures as compared with cells grown in nutrient excess.

Maintenance of communication in primary classrooms : some evidence for the role of elicitation and code-switching in English medium schools in Kenya, with implications for teaching

This is a study of specific aspects of classroom interaction primary school level in Kenya. The study entailed the identification of the sources of particular communication problems during the change-over period from Kiswahili to English medium teaching in two primary schools. There was subsequently an examination of the language resources which were employed by teachers to maintain pupil participation in communication in the light of the occurrence of possibility of occurrence of specific communication problems. The language resources which were found to be significant in this regard concerned firstly the use of different elicitation types by teachers to stimulate pupils into giving responses and secondly teachers' recourse to code-switching from English to Kiswahili and vice-versa. It was also found in this study that although the use of English as the medium of instruction in the classrooms which were observed resulted in certain communication problems, some of these problems need not have arisen if teachers had been more careful in their use of language. The consideration of this finding, after taking into account the role of different elicitation types and code-switching as interpretable from data samples had certain implications which are specified in the study for teaching in Kenyan primary schools. The corpus for the study consisted of audio-recordings of English, Science and Number-Work lessons which were later transcribed. Relevant data samples were subsequently extracted from transcripts for analysis. Many of the samples have examples of cases of communication breakdowns, but they also illustrate how teachers maintained interaction with pupils who had yet to acquire an operational mastery of English. This study thus differs from most studies on classroom interaction because of its basic concern with the examination of the resources available to teachers for overcoming the problem areas of classroom communication.

Agent Based Models of Competition and Collaboration

Swarm intelligence is a popular paradigm for algorithm design. Frequently drawing inspiration from natural systems, it assigns simple rules to a set of agents with the aim that, through local interactions, they collectively solve some global problem. Current variants of a popular swarm based optimization algorithm, particle swarm optimization (PSO), are investigated with a focus on premature convergence. A novel variant, dispersive PSO, is proposed to address this problem and is shown to lead to increased robustness and performance compared to current PSO algorithms. A nature inspired decentralised multi-agent algorithm is proposed to solve a constrained problem of distributed task allocation. Agents must collect and process the mail batches, without global knowledge of their environment or communication between agents. New rules for specialisation are proposed and are shown to exhibit improved eciency and exibility compared to existing ones. These new rules are compared with a market based approach to agent control. The eciency (average number of tasks performed), the exibility (ability to react to changes in the environment), and the sensitivity to load (ability to cope with differing demands) are investigated in both static and dynamic environments. A hybrid algorithm combining both approaches, is shown to exhibit improved eciency and robustness. Evolutionary algorithms are employed, both to optimize parameters and to allow the various rules to evolve and compete. We also observe extinction and speciation. In order to interpret algorithm performance we analyse the causes of eciency loss, derive theoretical upper bounds for the eciency, as well as a complete theoretical description of a non-trivial case, and compare these with the experimental results. Motivated by this work we introduce agent "memory" (the possibility for agents to develop preferences for certain cities) and show that not only does it lead to emergent cooperation between agents, but also to a signicant increase in efficiency.

The Evaluation of health and safety auditing systems

The specific objective of the research was to evaluate proprietary audit systems. Proprietary audit systems comprise question sets containing approximately 500 questions dealing with selected aspects of health and safety management. Each question is allotted a number of points and an organisation seeks to judge its health and safety performance by the overall score achieved in the audit. Initially it was considered that the evaluation method might involve comparing the proprietary audit scores with other methods of measuring safety performance. However, what appeared to be missing in the first instance was information that organisations could use to compare the contrast question set content against their own needs. A technique was developed using the computer database FileMaker Pro. This enables questions in an audit to be sorted into categories using a process of searching for key words. Questions that are not categorised by word searching can be identified and sorted manually. The process can be completed in 2-3 hours which is considerably faster than manual categorisation of questions which typically takes about 10 days. The technique was used to compare and contrast three proprietary audits: ISRS, CHASE and QSA. Differences and similarities between these audits were successfully identified. It was concluded that in general proprietary audits need to focus to a greater extent on identifying strengths and weaknesses in occupational health and safety management systems. To do this requires the inclusion of more probing questions which consider whether risk control measures are likely to be successful.

Wealth effects of mergers and acquisitions for US firms: using alternative pricing models

This empirical study employs a different methodology to examine the change in wealth associated with mergers and acquisitions (M&As) for US firms. Specifically, we employ the standard CAPM, the Fama-French three-factor model and the Carhart four-factor models within the OLS and GJR-GARCH estimation methods to test the behaviour of the cumulative abnormal returns (CARs). Whilst the standard CAPM captures the variability of stock returns with the overall market, the Fama-French factors capture the risk factors that are important to investors. Additionally, augmenting the Fama-French three-factor model with the Carhart momentum factor to generate the four-factor captures additional pricing elements that may affect stock returns. Traditionally, estimates of abnormal returns (ARs) in M&As situations rely on the standard OLS estimation method. However, the standard OLS will provide inefficient estimates of the ARs if the data contain ARCH and asymmetric effects. To minimise this problem of estimation efficiency we re-estimated the ARs using GJR-GARCH estimation method. We find that there is variation in the results both as regards the choice models and estimation methods. Besides these variations in the estimated models and the choice of estimation methods, we also tested whether the ARs are affected by the degree of liquidity of the stocks and the size of the firm. We document significant positive post-announcement cumulative ARs (CARs) for target firm shareholders under both the OLS and GJR-GARCH methods across all three methodologies. However, post-event CARs for acquiring firm shareholders were insignificant for both sets of estimation methods under the three methodologies. The GJR-GARCH method seems to generate larger CARs than those of the OLS method. Using both market capitalization and trading volume as a measure of liquidity and the size of the firm, we observed strong return continuations in the medium firms relative to small and large firms for target shareholders. We consistently observed market efficiency in small and large firm. This implies that target firms for small and large firms overreact to new information resulting in a more efficient market. For acquirer firms, our measure of liquidity captures strong return continuations for small firms under the OLS estimates for both CAPM and Fama-French three-factor models, whilst under the GJR-GARCH estimates only for Carhart model. Post-announcement bootstrapping simulated CARs confirmed our earlier results.

HRM systems, internal marketing and performance in Indian call centres:full research report ESRC end of award report, RES-000-22-1876

Considering the rapid growth of call centres (CCs) in India, its implications for businesses in the UK and a scarcity of research on human resource management (HRM) related issues in Indian CCs, this research has two main aims. First, to highlight the nature of HRM systems relevant to Indian call centres. Second, to understand the significance of internal marketing (IM) in influencing the frontline employees’ job-related attitudes and performance. Rewards being an important component of IM, the relationships between different types of rewards as part of an IM strategy, attitudes and performance of employees in Indian CCs will also be examined. Further, the research will investigate which type of commitment mediates the link between rewards and performance and why. The data collection will be via two phases. The first phase would involve a series of in-depth interviews with both the managers and employees to understand the functioning of CCs, and development of suitable HRM systems for the Indian context. The second phase would involve data collection through questionnaires distributed to the frontline employees and supervisors to examine the relationships among IM, employee attitudes and performance. Such an investigation is expected to contribute to development of better theory and practice.

Nonlinearity compensation in multi-rate 28 Gbaud WDM systems employing optical and digital techniques under diverse link configurations

Digital back-propagation (DBP) has recently been proposed for the comprehensive compensation of channel nonlinearities in optical communication systems. While DBP is attractive for its flexibility and performance, it poses significant challenges in terms of computational complexity. Alternatively, phase conjugation or spectral inversion has previously been employed to mitigate nonlinear fibre impairments. Though spectral inversion is relatively straightforward to implement in optical or electrical domain, it requires precise positioning and symmetrised link power profile in order to avail the full benefit. In this paper, we directly compare ideal and low-precision single-channel DBP with single-channel spectral-inversion both with and without symmetry correction via dispersive chirping. We demonstrate that for all the dispersion maps studied, spectral inversion approaches the performance of ideal DBP with 40 steps per span and exceeds the performance of electronic dispersion compensation by ~3.5 dB in Q-factor, enabling up to 96% reduction in complexity in terms of required DBP stages, relative to low precision one step per span based DBP. For maps where quasi-phase matching is a significant issue, spectral inversion significantly outperforms ideal DBP by ~3 dB.

Marketing responsibility in an era of economic and climatic challenge

Purpose – The purpose of this paper is to illustrate Michael Thomas's concept of civic professionalism and social trusteeship as a future alternative to the current marketing profession's code of conduct and to put this in the context of climate change and ecological sustainability as a model for firms everywhere. Design/methodology/approach – Review of the marketing profession's responsibility towards society, communities and the ecology of the planet in the twenty-first century in the light of climate change. Findings – The hypothesis for the paper emerges as: whether it is possible for Chinese firms to embrace the needs of twenty-first century global ecological sustainability in meeting their own economic requirements for development and financial prosperity. Research limitations/implications – Limited secondary research and primary research that is also limited in terms of scope. Practical implications – As we move into an era of Chinese economic supremacy, we marketers must face up to the responsibility we have towards balancing the progression of global economic development (and selling goods and services in global market systems) with our responsibility towards our cultural systems and the global ecological system (the global ecosystem), the home of all our economic wealth. Social implications – To extrapolate lessons and opportunities for firms from developing economies as they move towards global domination of world economic markets and, suggest strategies for sustainability that they can, and should, adopt. Originality/value – The paper presents a theoretical framework for a global strategy for sustainability, and provides a vision of marketing responsibility that embraces civic professionalism, social trusteeship and a strategy for sustainability.

HRM systems, internal marketing and performance in Indian call centres:non-technical summary (Research summary) ESRC end of award report, RES-000-22-1876. Swindon: ESRC

Considering the rapid growth of call centres (CCs) in India, its implications for businesses in the UK and a scarcity of research on human resource management (HRM) related issues in Indian CCs, this research has two main aims. First, to highlight the nature of HRM systems relevant to Indian call centres. Second, to understand the significance of internal marketing (IM) in influencing the frontline employees’ job-related attitudes and performance. Rewards being an important component of IM, the relationships between different types of rewards as part of an IM strategy, attitudes and performance of employees in Indian CCs will also be examined. Further, the research will investigate which type of commitment mediates the link between rewards and performance and why. The data collection will be via two phases. The first phase would involve a series of in-depth interviews with both the managers and employees to understand the functioning of CCs, and development of suitable HRM systems for the Indian context. The second phase would involve data collection through questionnaires distributed to the frontline employees and supervisors to examine the relationships among IM, employee attitudes and performance. Such an investigation is expected to contribute to development of better theory and practice.