http://196.220.128.81:8080/xmlui/handle/123456789/199 2026-08-12T15:06:34Z 2026-08-12T15:06:34Z KAREEM, Buliaminu http://196.220.128.81:8080/xmlui/handle/123456789/5980 2026-08-03T14:52:17Z 2004-09-01T00:00:00Z

Optimisation of Strategic Decisions Maintenance Jobshops KAREEM, Buliaminu The study has developed an integrated set of algorithms, heuristics and models for optimising maintenance service demand, crew Gang, maintenance tools/equipment, personnel interaction, spare parts inventory, job scheduling and costing, which are strategic in the establishment and running of a maintenance jobshop. The model was developed using an encompassing single-channel, multi-server queueing system. The developed package named Computer Aided Maintenance Strategic Decisions Optimisation and Planning (CAMSOP 2003) was validated with Akure, Osogbo, Ibadan, Ajaokuta and Lagos in Nigeria as case studies. Nonetheless, the database and structure of the software is flexible but robust enough to accommodate as many jobshops/cities as the storage capacity of the computer allows. The software always facilitates functions a comparison post-optimality analyses such as benefit-cost and sensitivity analyses were done to determine the most cost-effective rates for various service demands. xvi, 259p. : ill. ; 30cm

2004-09-01T00:00:00Z IDRIS, MUSIBAUDEEN OLATUND http://196.220.128.81:8080/xmlui/handle/123456789/5979 2026-08-03T14:38:56Z 2008-12-01T00:00:00Z

OPTIMISATION OF PRODUCTION PLANNING AND CONTROL IN JOBSHOPS IDRIS, MUSIBAUDEEN OLATUND Smooth production planning and control in jobshops has been hindered by inherent problems and peculiarities that surround management decisions in meeting the organisational objectives while satisfying the customers' requests. In solving these problems and streamlining the peculiarities, this study has developed mathematical models for eight strategic decisions that are pertinent in effective production planning and control in jobshops. These strategic decisions are: Demand Management, Manpower Planning, Tools and Equipment Planning, Material Requirement Planning, Job Scheduling, Cost Estimation, Due Dates, and Floor Shop Control and Record Management. Demand Management Model that was developed, determined the optimal forecast hour of demand and the optimal quantity of materials needed in the planning horizon using Exponential Smoothing Technique as the basis. The Manpower Planning Model determined the optimal number of manpower and its associated cost. The model permits internal transfer of full-time and part-time manpower with utilisation of excess and make up for shortage labour-hour, which served as control measure. Tools and Equipment Planning Model was also developed through which the optimal quantity of Tools and Equipment and cost, based on purchase, hire or contract strategy were determined. The development of Materials Requirement Planning Model was done and the optimal quantity and cost of material were determined based on modified Economic Order Quantity Model. A job-scheduling model was among the models developed to determine the commencement time and minimise the make span with inclusion of a dynamic operational schedule and re-schedule of jobs based on priority and first-come first-served principle. Cost Estimation Model based on modification of Aderoba (1997a)'s model with inclusion of bargaining permissibility was developed. A due-date model was formulated by modifying Akinnuli and Aderoba's (2000) model to include uncertainty in due dates and job crashing through adjustment of manpower, tools and equipment, and the scheduled jobs. A shop floor control and record management tools were designed to assign shop-order priority and work-in-progress quantity information for effective control in the areas of job location, shop order, accounting, efficiency and facility productivity. The tools track and monitor the flow of jobs, tools and equipment, material and manpower in the system. The eight (8) models were integrated using a heuristic method to evolve a hybrid model. Based on this, a software, JOBSIS_2007, in PHP (Hypertext Preprocessor) programming language, which costs maximum of 16% of the existing proprietary softwares, was developed for rapid implementation of the model. The validity of the model was tested using a jobshop located in Osogbo, Osun State, Nigeria. The period used for this purpose was classified into pre-implementation and implementation period. Pre- and Post- implementation results were compared using ANOVA, with the results from the implementation period. Based on this, it was revealed, among other things, that the model developed has enhanced capacity utilisation, improved marginal profit and created adequate records and documentations for planning . and control of production activities in the company. This study finally recommended salient points that could promote efficient usage of the model. ix, 290p. : ill. ; 30cm

2008-12-01T00:00:00Z AKINTUNDE, M. A. http://196.220.128.81:8080/xmlui/handle/123456789/5978 2026-08-03T13:31:56Z 2004-09-01T00:00:00Z

DEVELOPMENT OF A VAPOUR COMPRESSION REFRIGERATION SYSTEM BASED ON BALANCED POINTS BETWEEN OPERATIONAL UNITS AKINTUNDE, M. A. Vapour Compression Refrigerator (VCR), consists of four major components- evaporator, condenser, compressor and expansion device, which are connected in a cycle. VCR is commonly used in a wide range of commercial and industrial refrigeration applications and represents a substantial fraction of the installed refrigeration systems. As a result special attention has been focused on this system by many researchers. The goals of the researchers were to simulate the actual working of a vapour compression system with Carnot model as the benchmark. The task of getting the performance of Carnot model has proved difficult. Hence most researchers end-up in modeling performance of heat exchangers or a single component of the system. Though there are models for predicting the approximate performance of VCR, none of such models discussed, the "balanced point" between the four major components. This study was carried out to investigate the effects of balanced point on the system performance. In order to get the balanced point, the performance characteristics of each of the components were modelled in such a way that each of them depends on temperature only. These equations were used to develop a computer programme for refrigeration cycle. The model was then used to generate performance data, which compare very well with theoretical values. In order to validate the model, the generated data was used to design and construct a VCR that was tested and evaluated. Two experimental rigs were constructed for the tests. Rig "a" was that constructed using generated data from the design model, whilst Rig "b" was constructed from bought out components. The investigations were carried out under the same conditions. Effects of system performance based on operational parameters such as: compressor speed, refrigerant charge, condenser and evaporator temperatures and others, have been experimentally evaluated and the results compared. Present analysis and experimental investigations have shown that the model results are comparable to the experimental ones. The results obtained from rig a agreed well with those of the model, although there were some deviations. The deviations of the model results from those obtained in experiments are within the ranges of 16 % to 19 % for rig "a" and 28 % to 34 % for rig "b" respectively. xix, 111p. : ill. ; 30cm

2004-09-01T00:00:00Z OKE, PETER KAYODE http://196.220.128.81:8080/xmlui/handle/123456789/5976 2026-07-31T12:19:25Z 2009-11-01T00:00:00Z

DEVELOPMENT OF A MODEL FOR CAPACITY BUILDING FOR MACHINE TOOLS INDUSTRY IN NIGERIA OKE, PETER KAYODE With a view to achieve industrial growth, Nigeria has tried to establish a sound infrastructure involving among many other things, the establishment of an indigenous machine tools industry, Unfortunately, machine tools industry's development in Nigeria is adversely affected by uncertainties in capacity building in some areas which include technology, manpower, raw materials, equipment and energy. This thesis developed a robust model to achieve a desirable, dynamic and balanced capability of building and upgrading machine tools capacity in Nigeria. The model was developed for determining the machine tools technology capacity level in terms of machine design and machine fabrication capacity. The parameters determined from the model include, manpower, equipment, raw materials and energy capabilities for machine tools design and fabrication. The capacity outcomes were compared with established standards. The shortages and / or surpluses in each elemental capacity were determined using statistical difference method. This established appropriate funds to be allocated to each resource at specific time to yield required and appropriate resources capacity level within the time schedule. A dynamic programming technique with concept or adaptive control theory was used in machine tools resources capacity development. A feed back control system with adjustable coefficients was developed to minimize the effects of the uncertainty of the process parameters identified as manpower, raw materials, equipment and energy. The adjustable coefficient was made dynamic from available fund that was allocated in appropriate proportion depending on the level of development required for each system parameter. A software named CAMTCAD-2008 in Visual Basic was developed for effective implementation of the model. The model was validated with the data collected from Nigerian Machine Tools, Oshogbo. The result of the model has shown an inadequate level of development in resources for capacity building in the machine tools industry at a particular time. The model has revealed an immediate cost benefit in spreading the development of the system over the years: It was further observed from the result that the financial cumulative effect does not favour long-term period of system development: This may be due to variation in time value of money. This model further helped in identifying all the resources that have shortfall or surplus in their capacity levels and provided a clue of what the industry has to put in place in order to meet acceptable standards. The model gave an insight on future development and direction or advancement in, machine tools building in Nigeria thereby making a way for optimal development of machine tools that is technically sound, environmentally friendly and economically justifiable. The resulting software is amenable to practical application of technologically based qualitative forecasting strategies for planning, managing and development of machine tools industry in developing economies like Nigeria. This model has enhanced has enhanced a sustainable structure for future development and direction of advancement in machine tools industry. xix, 281p. : ill. ; 30cm

2009-11-01T00:00:00Z