Cost effectiveness of production control systems

This thesis deals with the problems associated with the planning and control of production, with particular reference to a small aluminium die casting company. The main problem areas were identified as: (a) A need to be able to forecast the customers demands upon the company's facilities. (b) A need to produce a manufacturing programme in which the output of the foundry (or die casting section) was balanced with the available capacity in the machine shop. (c) The need to ensure that the resultant system enabled the company's operating budget to have a reasonable chance of being achieved. At the commencement of the research work the major customers were members of the automobile industry and had their own system of forecasting, from which they issued manufacturing schedules to their component suppliers, The errors in the forecast were analysed and the distributions noted. Using these distributions the customer's forecast was capable of being modified to enable his final demand to be met with a known degree of confidence. Before a manufacturing programme could be developed the actual manufacturing system had to be reviewed and it was found that as with many small companies there was a remarkable lack of formal control and written data. Relevant data with regards to the component and the manufacturing process had therefore to be collected and analysed. The foundry process was fixed but the secondary machining operations were analysed by a technique similar to Component Flow Analysis and as a result the machines were arranged in a series of flow lines. A system of manual production control was proposed and for comparison, a local computer bureau was approached and a system proposed incorporating the production of additional management information. These systems are compared and the relative merits discussed and a proposal made for implementation.

River basin surveillance using remotely sensed data: a water resources information management system

This thesis describes the development of an operational river basin water resources information management system. The river or drainage basin is the fundamental unit of the system; in both the modelling and prediction of hydrological processes, and in the monitoring of the effect of catchment management policies. A primary concern of the study is the collection of sufficient and sufficiently accurate information to model hydrological processes. Remote sensing, in combination with conventional point source measurement, can be a valuable source of information, but is often overlooked by hydrologists, due to the cost of acquisition and processing. This thesis describes a number of cost effective methods of acquiring remotely sensed imagery, from airborne video survey to real time ingestion of meteorological satellite data. Inexpensive micro-computer systems and peripherals are used throughout to process and manipulate the data. Spatial information systems provide a means of integrating these data with topographic and thematic cartographic data, and historical records. For the system to have any real potential the data must be stored in a readily accessible format and be easily manipulated within the database. The design of efficient man-machine interfaces and the use of software enginering methodologies are therefore included in this thesis as a major part of the design of the system. The use of low cost technologies, from micro-computers to video cameras, enables the introduction of water resources information management systems into developing countries where the potential benefits are greatest.

A rationale for the optimisation by computer methods of the efficient use of metals and materials

The aim of the research project was to gain d complete and accurate accounting of the needs and deficiencies of materials selection and design data, with particular attention given to the feasibility of a computerised materials selection system that would include application analysis, property data and screening techniques. The project also investigates and integrates the three major aspects of materials resources, materials selection and materials recycling. Consideration of the materials resource base suggests that, though our discovery potential has increased, geologic availability is the ultimate determinant and several metals may well become scarce at the same time, thus compounding the problem of substitution. With around 2- to 20- million units of engineering materials data, the use of a computer is the only logical answer for scientific selection of materials. The system developed at Aston is used for data storage, mathematical computation and output. The system enables programs to be run in batch and interactive (on-line) mode. The program with modification can also handle such variables as quantity of mineral resources, energy cost of materials and depletion and utilisation rates of strateqic materials. The work also carries out an in-depth study of copper recycling in the U.K. and concludes that, somewhere in the region of 2 million tonnes of copper is missing from the recycling cycle. It also sets out guidelines on product design and conservation policies from the recyclability point of view.

Development of a computerised library system in the construction industry

This thesis examines the ways that libraries have employed computers to assist with housekeeping operations. It considers the relevance of such applications to company libraries in the construction industry, and describes more specifically the development of an integrated cataloguing and loan system. A review of the main features in the development of computerised ordering, cataloguing and circulation control systems shows that fully integrated packages are beginning to be completed, and that some libraries are introducing second generation programs. Cataloguing is the most common activity to be computerised, both at national and company level. Results from a sample of libraries in the construction industry suggest that the only computerised housekeeping system is at Taylor Woodrow. Most of the firms have access to an in-house computer, and some of the libraries, particularly those in firms of consulting engineers, might benefit from computerisation, but there are differing attitudes amongst the librarians towards the computer. A detailed study of the library at Taylor Woodrow resulted in a feasibility report covering all the areas of its activities. One of the main suggestions was the possible use of a computerised loans and cataloguing system. An integrated system to cover these two areas was programmed in Fortran and implemented. This new system provides certain benefits and saves staff time, but at the cost of time on the computer. Some improvements could be made by reprogramming, but it provides a general system for small technical libraries. A general equation comparing costs for manual and computerised operations is progressively simplified to a form where the annual saving from the computerised system is expressed in terms of staff and computer costs and the size of the library. This equation gives any library an indication of the savings or extra cost which would result from using the computerised system.

Measurement of productivity and cost of the direct labour organisation within highways maintenance departments

The objective of this thesis is to investigate, through an empirical study, the different functions of the highways maintenance departments and to suggest methods by means of which road maintenance work could be carried out in a more efficient way by utilising its resources of men, material and plant to the utmost advantage. This is particularly important under the present circumstances of national financial difficulties which have resulted in continuous cuts in public expenditure. In order to achieve this objective, the researcher carried out a survey among several Highways Authorities by means of questionnaire and interview. The information so collected was analysed in order to understand the actual, practical situation within highways manintenance departments, and highlight any existing problems, and try to answer the question of how they could become more efficient. According to the results obtained by the questionnaire and the interview, and the analysis of these results, the researcher concludes that it is the management system where least has been done, and where problems exist and are most complex. The management of highways maintenance departments argue that the reasons for their problems include both financial and organisational difficulties, apart from the political aspect and nature of the activities undertaken. The researcher believes that this ought to necessitate improving the management's analytical tools and techniques in order to achieve the most effective way of performing each activity. To this end the researcher recommends several related procedures to be adopted by the management of the highways maintenance departments. These recommendations, arising from the study, involve the technical, practical and human aspects. These are essential factors of which management should be aware - and certainly should not neglect - in order to achieve its objectives of improved productivity in the highways maintenance departments.

Fish farm effluent control and the development of an expert system

In recent years, freshwater fish farmers have come under increasing pressure from the Water Authorities to control the quality of their farm effluents. This project aimed to investigate methods of treating aquacultural effluent in an efficient and cost-effective manner, and to incorporate the knowledge gained into an Expert System which could then be used in an advice service to farmers. From the results of this research it was established that sedimentation and the use of low pollution diets are the only cost effective methods of controlling the quality of fish farm effluents. Settlement has been extensively investigated and it was found that the removal of suspended solids in a settlement pond is only likely to be effective if the inlet solids concentration is in excess of 8 mg/litre. The probability of good settlement can be enhanced by keeping the ratio of length/retention time (a form of mean fluid velocity) below 4.0 metres/minute. The removal of BOD requires inlet solids concentrations in excess of 20 mg/litre to be effective, and this is seldom attained on commercial fish farms. Settlement, generally, does not remove appreciable quantities of ammonia from effluents, but algae can absorb ammonia by nutrient uptake under certain conditions. The use of low pollution, high performance diets gives pollutant yields which are low when compared with published figures obtained by many previous workers. Two Expert Systems were constructed, both of which diagnose possible causes of poor effluent quality on fish farms and suggest solutions. The first system uses knowledge gained from a literature review and the second employs the knowledge obtained from this project's experimental work. Consent details for over 100 fish farms were obtained from the public registers kept by the Water Authorities. Large variations in policy from one Authority to the next were found. These data have been compiled in a computer file for ease of comparison.