3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item Scheduling in the South African construction industry(1989) Rudzinske, Paul EricThis research report investigates the use and sophistication of scheduling by the South African construction industry, by means of a postal survey and personal interviews. Furthermore, the construction industry's past and present use of scheduling is comparatively analyzed with that of selected overseas countries. A brief description of the various scheduling techniques is provided, together with the histories of these techniques. The primary conclusion of the research work was that the larger companies showed greater dedication to their scheduling, as well as implementing more advanced scheduling techniques. The emergence of cheaper computer systems showed definite impacts on the sophistication and effectiveness of scheduling, and indications of future impacts by computers were also found. The use of network-type scheduling techniques had also expanded, and further growth in the use of network-type schedules was indicated.Item Agent based simulation of the dial-a-flight problem(2018) Reddy, Daniel TharushenAgent based simulation and modelling (ABSM) has been noted as a novel method in solving complex problems. This dissertation makes use of the ABSM method in conjunction with a Genetic Algorithm to nd good solutions to the dial-a- ight problem. The task is to generate a schedule for a heterogeneous eet of aircraft, with the objective to reduce operational cost but maintain customer satisfaction. By making use of booking list data from an air taxi business, operating in the Okavango Delta, two agent based models were designed, the rst makes use of multi-criteria decision analysis (MCDA) and the other a method proposed by Campbell [7], to test their e ectiveness against either upper bound or manual solutions. The solution quality varied between tests, with booking list sizes between 10 and 200 requests producing improvements to the upper bound and manual results with a mean improvement from the benchmarks of 1.61%. The method could also be re ned further by adopting improvement mechanisms to nal schedules or by making use of retrospective decision making aided by self learning techniques.Item An approach to solving a scheduling problem arising in industry(2018) Stoltz, Adham RaymondThis work is a result of the necessity to resolve a real world problem: a call centre capacity problem. The result of the capacity challenge is a high cost of operations and large number of disgruntled customers. The research comprises two components: developing a new mathematical model as an extension to existing scheduling problems and then also the industrial engineering component of implementing this new scheduling model into the call centre operation in which the problem was identi ed. The real world problem is introduced and discussed in detail, with particular emphasis placed on the unique features and events which give rise to the capacity problem. The problem is shown to share many features with the class of problems known as Scheduling Problems. Particular attention is paid to the sub classes of Resource Constrained Project Scheduling (RCPSP) and Resource Levelling Problems (RLP). A review of the literature relating to these classes of problems, as well as the extensions and features that are relevant to the real world problem, is presented. The real world problem is discussed in more detail and framed in terms of the conventions that have been established for RCPSP and RLP. Similarities and di erences between the real world problem and established models from literature are discussed. The special and unique features of this problem are then shown to be: the need to perform scheduling on a batch basis every day, without knowledge of what will occur the following day and also the requirement that resources (call centre capacity) are fully utilized and not exceeded. There is also no terminal state which can be planned for, batch scheduling continues inde nitely. The result of the research is that a new mathematical model called the Critical Time Window Resource Levelling Problem (CTWRLP) with the Continual Rescheduling method is developed and proposed as a method for solving the real world scheduling problem. This method addresses all the requirements of the real world problem. An approach to solving the model in the practical environment is also presented. This involves additional pre-processing required to prepare all inputs for the scheduling model, namely creating sub-models for calculating resource consumption and resource availability. The global optimization technique of Simulated Annealing is then introduced as this is the method chosen to solve the optimization component of the CTWRLP. The CTWRLP model is implemented in the call centre. The practical algorithm, numerical solution technique, results and success of the model are presented.Item Research into a method of crew scheduling for suburban rail transport using heuristic and linear programming techniques(2015-01-14) Comrie, Andrew NevilleCrew schedules on the South African Transport Services are done by roster compilers at depots. A method that uses heuristic and mathematical programming algorithms was developed to replace existing hand methods. It is a two stage method that will use a microcomputer to assist roster compilers to draw up crew schedules. Initially timetables are subdivided into shifts and then they are combined into crew schedules. The solution, which produces a significant improvement compared with an existing crew schedule and an existing method, has been accepted in principle and computer programming has begun. In Appendix E another heuristic for the scheduling of league matches is described.