23 resultados para distribution system planning

em Aston University Research Archive


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The development of an information system in Caribbean public sector organisations is usually seen as a matter of installing hardware and software according to a directive from senior management, without much planning. This causes huge investment in procuring hardware and software without improving overall system performance. Increasingly, Caribbean organisations are looking for assurances on information system performance before making investment decisions not only to satisfy the funding agencies, but also to be competitive in this dynamic and global business world. This study demonstrates an information system planning approach using a process-reengineering framework. Firstly, the stakeholders for the business functions are identified along with their relationships and requirements. Secondly, process reengineering is carried out to develop the system requirements. Accordingly, information technology is selected through detailed system requirement analysis. Thirdly, cost-benefit analysis, identification of critical success factors and risk analysis are carried out to strengthen the selection. The entire methodology has been demonstrated through an information system project in the Barbados drug service, a public sector organisation in the Caribbean.

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More-electric vehicle technology is becoming prevalent in a number of transportation systems because of its ability to improve efficiency and reduce costs. This paper examines the specific case of an Uninhabited Autonomous Vehicle (UAV), and the system topology and control elements required to achieve adequate dc distribution voltage bus regulation. Voltage control methods are investigated and a droop control scheme is implemented on the system. Simulation results are also presented.

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A free space quantum key distribution system has been demonstrated. Consideration has been given to factors such as field of view and spectral width, to cut down the deleterious effect from background light levels. Suitable optical sources such as lasers and RCLEDs have been investigated as well as optimal wavelength choices, always with a view to building a compact and robust system. The implementation of background reduction measures resulted in a system capable of operating in daylight conditions. An autonomous system was left running and generating shared key material continuously for over 7 days. © 2009 Published by Elsevier B.V..

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Purpose – The purpose of this paper is to investigate the “last mile” delivery link between a hub and spoke distribution system and its customers. The proportion of retail, as opposed to non-retail (trade) customers using this type of distribution system has been growing in the UK. The paper shows the applicability of simulation to demonstrate changes in overall delivery policy to these customers. Design/methodology/approach – A case-based research method was chosen with the aim to provide an exemplar of practice and test the proposition that simulation can be used as a tool to investigate changes in delivery policy. Findings – The results indicate the potential improvement in delivery performance, specifically in meeting timed delivery performance, that could be made by having separate retail and non-retail delivery runs from the spoke terminal to the customer. Research limitations/implications – The simulation study does not attempt to generate a vehicle routing schedule but demonstrates the effects of a change on delivery performance when comparing delivery policies. Practical implications – Scheduling and spreadsheet software are widely used and provide useful assistance in the design of delivery runs and the allocation of staff to those delivery runs. This paper demonstrates to managers the usefulness of investigating the efficacy of current design rules and presents simulation as a suitable tool for this analysis. Originality/value – A simulation model is used in a novel application to test a change in delivery policy in response to a changing delivery profile of increased retail deliveries.

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This paper presents an effective decision making system for leak detection based on multiple generalized linear models and clustering techniques. The training data for the proposed decision system is obtained by setting up an experimental pipeline fully operational distribution system. The system is also equipped with data logging for three variables; namely, inlet pressure, outlet pressure, and outlet flow. The experimental setup is designed such that multi-operational conditions of the distribution system, including multi pressure and multi flow can be obtained. We then statistically tested and showed that pressure and flow variables can be used as signature of leak under the designed multi-operational conditions. It is then shown that the detection of leakages based on the training and testing of the proposed multi model decision system with pre data clustering, under multi operational conditions produces better recognition rates in comparison to the training based on the single model approach. This decision system is then equipped with the estimation of confidence limits and a method is proposed for using these confidence limits for obtaining more robust leakage recognition results.

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Relationships between organizations can be characterized by cooperation, conflict, and change. In this dissertation we study cooperation between organizations by investigating how norms in relationships can enhance innovativeness and subsequently impact relationship performance. We do so by incorporating both beneficial aspects of long term relationships as well as “dark side” factors that may decrease innovativeness. This provides a balanced assessment of the factors increasing and decreasing the performance of relationships. Next, we study conflict between organizations by taking a network view on conflict which helps explain why organizations react to conflict. We find stakeholders to have an effect on channel conflict responsiveness. Finally we study change by means of an organization’s ability to successfully add an Internet channel to their distribution system in order to sell its products or services directly to the end-user. We find that an Internet channel is best implemented by organizations that are flexible and we identify several circumstances under which this flexibility is highest.

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Studies into gas-liquid flow patterns were carried out on commercial scale sieve trays where the ratio of froth depth to flow path length is typical of that found in practice. Experiments were conducted on a 2.44 m diameter air-water distillation simulator, in which flow patterns were investigated by direct observation, using directional flow pointers; by water cooling, to simulate mass transfer; and by height of clear liquid measurements across the tray. The flow rates used are typical of those found in practice. The approach adopted was to investigate the effect of the gas flow on the liquid flow by comparing water only flow patterns across an unperforated tray with air-water flow patterns on perforated trays. Initial gas-liquid contacting experiments on the 6.35 mm hole tray showed that, under certain conditions, the gas flow pattern beneath the test tray can have a significant effect on the tray liquid flow pattern such that gas-driven liquid circulation was produced. This was found to be a function of this particular air-water simulator design, and as far as is known this is the first time that this phenomenon has been observed. Consequently non-uniform gas flow effects were removed by modification of the gas distribution system. By eliminating gas circulation effects, the effect of the gas flow on the separation of liquid flow was similar to that obtained on the 1.0 mm hole tray (Hine, 1990). That is, flow separation occurred at the ends of the inlet downcomer which produced large circulating zones along the tray segments both on the non-perforated and perforated trays. The air when forced through the liquid, inhibited circulating flow such that it only occurred at high water inlet velocities. With the 6.35 mm hole tray, the growth and velocity of circulating flow was reduced at high superficial air velocities, and in the experiments to simulate distillation, liquid was in forward flow over most of the tray.

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Retail customers provide a number of significant challenges to the efficiency and effectiveness of distribution systems. These challengers include shorter delivery windows, fluctuating volumes and a wider product mix. This paper demonstrates the use of discrete-event simulation to investigate policy issues regarding the incorporation of retail customers in a road delivery network from the spoke terminal of a hub and spoke distribution system. In particular a comparison of a mixed (retail and non-retail) delivery policy with a dedicated retail delivery run is made.

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OBJECTIVE: To determine the distribution of the pathological changes in the neocortex in multiple-system atrophy (MSA). METHOD: The vertical distribution of the abnormal neurons (neurons with enlarged or atrophic perikarya), surviving neurons, glial cytoplasmic inclusions (GCI) and neuronal cytoplasmic inclusions (NI) were studied in alpha-synuclein-stained material of frontal and temporal cortex in ten cases of MSA. RESULTS: Abnormal neurons exhibited two common patterns of distribution, viz., density was either maximal in the upper cortex or a bimodal distribution was present with a density peak in the upper and lower cortex. The NI were either located in the lower cortex or were more uniformly distributed down the cortical profile. The distribution of the GCI varied considerably between gyri and cases. The density of the glial cell nuclei was maximal in the lower cortex in the majority of gyri. In a number of gyri, there was a positive correlation between the vertical densities of the abnormal neurons, the total number of surviving neurons, and the glial cell nuclei. The vertical densities of the GCI were not correlated with those of the surviving neurons or glial cells but the GCI and NI were positively correlated in a small number of gyri. CONCLUSION: The data suggest that there is significant degeneration of the frontal and temporal lobes in MSA, the lower laminae being affected more significantly than the upper laminae. Cortical degeneration in MSA is likely to be secondary to pathological changes occurring within subcortical areas.

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Purpose – The purpose of the paper is to use a case study setting involving the implementation of an enterprise resource planning (ERP) system to expose and analyze the conflicts in the characterizations of the post bureaucratic organisation (PBO) in the literature. ERP implementations are often accompanied by increasing levels of stress in organizations that place pressures on organizational relationships and structures. Additionally, ERPs are regarded as introducing their own techno-logic of centralization, standardization and formalization that provides an apparent contrast to the exhortations about employee empowerment. Design/methodology/approach – A case study of ERP implementation in a medium-sized entity is presented. The paper explores aspects of ERP and PBO from the context of postmodern organization theory. Findings – Some concerns about PBO identified in the literature are reflected in the case situation. For example, there is a commitment to give up private time and work flexibly by some employees. The paper also provides evidence of the way the management team substitute their reliance on a key individual knowledge worker for that of an ERP system and external vendor support. Paradoxically, trust in that same knowledge worker and between core users of the system is essential to enable the implementation of the system. Originality/value – This paper adds empirical insight to a predominantly theoretical literature. The case evidence indicates some conflicting implications in the concurrent adoption of PBO and ERP.

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To study the topographic distribution of the pathology in multiple system atrophy (MSA). Pattern analysis was carried out using a-synuclein immunohistochemistry in 10 MSA cases. The glial cytoplasmic inclusions (GCI) were distributed randomly or in large clusters. The neuronal inclusions (NI) and abnormal neurons were distributed in regular clusters. Clusters of the NI and abnormal neurons were spatially correlated whereas the GCI were not spatially correlated with either the NI or the abnormal neurons. The data suggest that the GCI represent the primary change in MSA and the neuronal pathology develops secondary to the glial pathology.

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From a manufacturing perspective, the efficiency of manufacturing operations (such as process planning and production scheduling) are the key element for enhancing manufacturing competence. Process planning and production scheduling functions have been traditionally treated as two separate activities, and have resulted in a range of inefficiencies. These include infeasible process plans, non-available/overloaded resources, high production costs, long production lead times, and so on. Above all, it is unlikely that the dynamic changes can be efficiently dealt with. Despite much research has been conducted to integrate process planning and production scheduling to generate optimised solutions to improve manufacturing efficiency, there is still a gap to achieve the competence required for the current global competitive market. In this research, the concept of multi-agent system (MAS) is adopted as a means to address the aforementioned gap. A MAS consists of a collection of intelligent autonomous agents able to solve complex problems. These agents possess their individual objectives and interact with each other to fulfil the global goal. This paper describes a novel use of an autonomous agent system to facilitate the integration of process planning and production scheduling functions to cope with unpredictable demands, in terms of uncertainties in product mix and demand pattern. The novelty lies with the currency-based iterative agent bidding mechanism to allow process planning and production scheduling options to be evaluated simultaneously, so as to search for an optimised, cost-effective solution. This agent based system aims to achieve manufacturing competence by means of enhancing the flexibility and agility of manufacturing enterprises.

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The thesis describes the work carried out to develop a prototype knowledge-based system 'KBS-SETUPP' to generate process plans for the manufacture of seamless tubes. The work is specifically related to a plant in which hollows are made from solid billets using a rotary piercing process and then reduced to required size and finished properties using the fixed plug cold drawing process. The thesis first discusses various methods of tube production in order to give a general background of tube manufacture. Then a review of the automation of the process planning function is presented in terms of its basic sub-tasks and the techniques and suitability of a knowledge-based system is established. In the light of such a review and a case study, the process planning problem is formulated in the domain of seamless tube manufacture, its basic sub-tasks are identified and capabilities and constraints of the available equipment in the specific plant are established. The task of collecting and collating the process planning knowledge in seamless tube manufacture is discussed and is mostly fulfilled from domain experts, analysing of existing manufacturing records specific to plant, textbooks and applicable Standards. For the cold drawing mill, tube-drawing schedules have been rationalised to correspond with practice. The validation of such schedules has been achieved by computing the process parameters and then comparing these with the drawbench capacity to avoid over-loading. The existing models cannot be simulated in the computer program as such, therefore a mathematical model has been proposed which estimates the process parameters which are in close agreement with experimental values established by other researchers. To implement the concepts, a Knowledge-Based System 'KBS- SETUPP' has been developed on Personal Computer using Turbo- Prolog. The system is capable of generating process plans, production schedules and some additional capabilities to supplement process planning. The system generated process plans have been compared with the actual plans of the company and it has been shown that the results are satisfactory and encouraging and that the system has the capabilities which are useful.

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The aim of this thesis is to examine the specific contextual factors affecting the applicability and development of the planning, programming, budgeting system (P.P.B.S.) as a systems approach to public sector budgeting. The concept of P.P.B.S. as a systems approach to public sector budgeting will first be developed and the preliminary hypothesis that general contextual factors may be classified under political, structural and cognitive headings will be put forward. This preliminary hypothesis will be developed and refined using American and early British experience. The refined hypothesis will then be tested in detail in the case of the English health and personal social services (H.P.S.S.), The reasons for this focus are that it is the most recent, the sole remaining, and the most significant example in British central government outside of defence, and is fairly representative of non-defence government programme areas. The method of data collection relies on the examination of unpublished and difficult to obtain central government, health and local authority documents, and interviews with senior civil servants and public officials. The conclusion will be that the political constraints on, or factors affecting P.P.B.S., vary with product characteristics and cultural imperatives on pluralistic decision-making; that structural constraints vary with the degree of coincidence of programme and organisation structure and with the degree of controllability of the organisation; and finally, that cognitive constraints vary according to product characteristics, organisational responsibilities, and analytical effort.