The research relates to the modelling and control of multi-stage production - inventory systems in high volume low-mix manufacturing industry. Examples of such class include typically the automotive and white goods industries. The research has included the investigation of available mathematical control techniques in the "optimal" control of manufacturing systems, a study of their applicability and the practical implications of their use in a manufacturing environment. Earlier work in the field of multivariable control theory has shown the potential of application in industrial management. In this thesis, previous work is extended whereby explicit consideration is given to some practical constraints existing in a typical manufacturing environment. It is considered that the research carried out has contributed to the development of multivariable control theory as applied to practical control problems with constraints. This has been achieved by the use of structured canonical forms and the exploitation of their particular ordered properties, resulting in the development of practical control models. The automotive industry has been used as a practical case study and modelled as a linear discrete-time control problem. The models have been developed in close liaison with a car manufacturing company in the U.K., and have been shown to produce practical control policies in the areas of both capacity requirements planning and inter-stage float levels. Particular attention is given to existing practical constraints of such systems. The approach is extended to deal effectively with a more general multi-product environment. It is noted that multi-product environment is of a more complex nature than single product since it involves the consideration of competition for the limited resources that have to be shared out "sub-optimally", in addition to providing smooth control of the responses. The development and application of multivariable control theory as described in this thesis is shown to provide an effective methodology for the solution of dynamic production control problems of multi-stage production-inventory systems in both single and multi-product environments.

by Shing-chiang Wong. / Bibliography: leaf 73 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1986

by Wing-yi, Tam. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 74-77). / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Cox and Lewis' Model and Weibull Process Model / Chapter Section 1 --- Nonhomogeneous Poisson Process (NHPP) --- p.5 / Chapter Section 2 --- Cox and Lewis' Model --- p.7 / Chapter Section 3 --- Weibull Process Model --- p.11 / Chapter Section 4 --- Test of NHPP --- p.14 / Chapter Chapter 3 --- Inference for Geometric Process with Inverse Gaussian Distribution / Chapter Section 1 --- Geometric Process (GP) --- p.18 / Chapter Section 2 --- Inverse Gaussian Distribution (IG) --- p.22 / Chapter Section 3 --- Simulation --- p.25 / Chapter Section 4 --- Conclusion --- p.33 / Chapter Chapter 4 --- Comparison Geometric Process Model and NHPP model in Fitting a Point Process / Chapter Section 1 --- Introduction --- p.34 / Chapter Section 2 --- Real Data Examples --- p.39 / Chapter Section 3 --- Conclusion --- p.45 / Tables and Graphs --- p.48 / Appendices --- p.71 / References --- p.74

This thesis is concerned with the engineering design requirement and the process by which it is elicited, evolved and recorded. The purpose of the research reported in the work is to achieve a more complete understanding of the engineering design requirement, and to apply that understanding to the better support of designers during the design requirement capture phases of the design process. Two perspectives dominate the approach to the research. The first concerns the relation between the design process and human cognition. The research subject is seen as being fundamentally a product of the human mind and that such things as knowledge, language and meaning – the things commonly associated with cognition – are crucial to its proper understanding. The second perspective is informed by the view that the development of the design requirement can be seen as a knowledge-intensive process of communication. Thus, understanding communication between humans and some aspects of communication failure can assist in understanding and remedying failure in design requirement capture.

This research work investigates the information requirements of the engineering designer during the early phases of the design process. In particular, it focuses on the use of standard components, and the information requirements associated with them. The research presents a system for the representation of information, both formal catalogue data, and also what the author has termed "Informal Information". Also presented is a system for the representation of catalogue information that will allow for standard component catalogue interfacing.

The modelling of transport processes in biological systems is one of the main theoretical challenges in physics, chemistry and biology. This is motivated by their essential role in the emergence of diseases, like tumour metastases, which originate from the spontaneous migration of cancer cells. Thus, improvements in their understanding could potentially pave the way for an outstanding innovation of present-day techniques in medicine. These processes often exhibit anomalous properties, which are qualitatively described by the power-law scaling of their mean square displacement, compared to the linear one of normal diffusion. Such behaviour has been often successfully explained by the celebrated continuous-time random walk model. However, recent experimental studies revealed the existence of both more complicated mean square displacement behaviour and anomalous features in other characteristic observables, e.g. the position-velocity statistics or the two point correlation functions of either the velocity or the position. Thus, in order to understand the anomalous diffusion recorded in these experiments and assess the microscopic processes underlying the observed macroscopic dynamics, one needs to have a complete tool-kit of techniques and models that can be readily compared with the experimental datasets. In this Thesis, we contribute to the construction of such a complete framework by fully characterising anomalous processes, which are described by means of a continuoustime random walk with general waiting time distributions and/or external forces that are exerted both during the jumps (as in the original model) and the waiting times. In the first case we derive both the joint statistics of these processes and their observables, specifically by obtaining a generalised fractional Feynman-Kac formula, and their multipoint correlation functions and employ them to fit the mean square displacement data of diffusing mitochondria. This result supports the experimental relevance of our formalism, which comprises general formulas for several quantities that can provide readily predictable tests to be checked in experiments. In the second case, we characterise the new anomalous processes by means of Langevin equations driven by a novel type of non Gaussian noise, which reproduces the typical fluctuations of a free diffusive continuous-time random walk. For a constant external force, we also obtain the fractional evolution equations of their position probability density function and show that, contrarily to continuous-time random walks, they are weak Galilean invariant, i.e., their position distribution in different Galilean frames is obtained by shifting the sample variable according to the relative motion of the frames. Thus, these processes provide a suitable frame-invariant framework, that could be employed to investigate the stochastic thermodynamics of anomalous diffusive processes.

The development of a Semi-Open Refrigeration Cycle had been shown to be of economic value to the process of crystallisation. The experimentation took the form of several bench scale experiments to develop the designs of the individual vessels that were to constitute the final pilot plant. In view of the safety hazards involved with a plant contacting Sulphuric Acid and Liquid Butane, a substantial Hazop and HAZAN study has been carried out. From this data the pilot plant was constructed, with all necessary safety features. Computer monitoring and partial computer control was installed. The pilot plant was operated as a closed loop for extended periods, to enable the production of both Iron (2) and Copper (2) Sulphates to be produced on a continuous basis. The results showed that the crystals produced are of a small size, indicative of the instantaneous chilling of the mother liquor and are not contaminated to a significant degree with the refrigerant. The thermal efficiency of the cycle was lower than expected at 80%, but improvements in insulation coupled with the redesign of the condenser, eliminating the necessity for a separator vessel, should increase this to the expected 90%.

No description available.

No description available.

No description available.