Browsing by Author "Nyanga, L."
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- ItemAgent based job scheduling for a vehicle engine reconditioning machine shop(Faculty of Engineering, Department of Industrial Engineering, Stellenbosch University, 2016) Nyanga, L.; Van der Merwe, A. F.; Burawa, M.; Matope, S.; Dewa, M. T.ENGLISH ABSTRACT: Job scheduling at a machine shop is a multi-decision criteria problem whose skills are acquired after some years of experience. For Small, Medium to Micro Enterprises (SMMEs) with limited machinery the objective when scheduling jobs should not only focus on machine utilization but also on the increase of job through put. The paper presents an agent based job scheduling system for a vehicle engine reconditioning machine shop to assist decision makers in job scheduling. The Analytic Hierarchy Process (AHP) method was used to compute the relative weights of each decision criteria used for job scheduling considering the job priority. The value of the job, the number of operations to be performed, the engine type, the frequency of the customer and the company to customer relationship rating are used to prioritize the jobs. A Multi Agent System (MAS) comprising of the provider, job allocator and machine agents is developed using the Java Agent development framework (JADE) methodology and modelled using Unified Modelling Language (UML 2). The provider agent schedules all the jobs based on job weight and earliest due dates. The job allocator agent is responsible for making sure that all the scheduled jobs are allocated to all the machines after which they are registered as complete jobs and can leave the system.
- ItemDesign of a multi agent system for machine selection(Faculty of Engineering, Department of Industrial Engineering, Stellenbosch University, 2016) Nyanga, L.; Van der Merwe, A. F.; Tsakira, C.; Matope, S.; Dewa, M. T.ENGLISH ABSTRACT: In a machine shop effective assignment of jobs to machines is a multi-criteria decision making problem which is usually done by professionals and experienced planners. The skill of job assignment becomes handy in machine shops which are in the Small, Medium to Micro Enterprises (SMMEs) category as they work on a variety of products with limited machinery. The paper presents a machine selection system for helping decision makers when selecting machines to be scheduled. Customer order parameters which include product weight, clamping force, mould dimensions, due date and lead time are used to select moulding machines suitable to manufacture the desired parts. The criteria for machine selection was developed using Analytical Hierarchy Process (AHP) were quality, time and cost were considered as the key parameters. The available machines which meet the requirements for moulding a desired part are then made to compete for the part using an English auction. A Multi Agent System consisting of a managing agent, administrator and bidding agents was developed to conduct the auction that takes place between machine agents viewed as potential contractors representing available machines in the production line. The multi agent system is developed using Java Agent Development framework (JADE). An injection moulding plant with 11 injection moulders was used as a case study for application of the system.
- ItemE-manufacturing - the roadmap for South African manufacturers(Stellenbosch : Stellenbosch University, Department of Industrial Engineering, 2011-09) Nyanga, L.; Van der Merwe, A. F.Globalization and the internet have given customers a wide choice of products to choose from and they are now expecting a lot from products. Customers are demanding more value, less risk and better integration of products hence products now have a shorter product life cycle. E-manufacturing can help companies to optimize the use of production assets, reduce production cycle times and costs to meet these customer requirements. The paper shows factors that influenced an economy to successfully implement an emanufacturing model that transformed the economy from a struggling economy into an advanced economy. E-manufacturing models are discussed. Taiwan is used as a case study of how engineering chain can be utilized for SMEs to enjoy equally or even higher competitive advantage than their larger competitors by appropriately utilizing external networks. The situation in South Africa shows that the country can benefit from the growth of SMEs and e-manufacturing if networks and a culture of sharing information are built among SMEs and companies in the country.
- ItemAn empirical analysis of operational disturbances and their impact on business performance in manufacturing firms : case tooling industry South Africa(South African Institute for Industrial Engineering, 2014) Dewa, Mncedisi Trinity; Matope, Stephen; Van der Merwe, Andre Francois; Nyanga, L.ENGLISH ABSTRACT: Globalization has managed to break trade barriers and the manufacturing environment has become more competitive. Market share is now determined by quality of goods and services irrespective of location. Today’s business environment for manufacturers requires flexible, responsive and robust systems, which produce a variety of products at competitive prices. To gain a competitive edge, the paradigms of e-manufacturing and distributed manufacturing have been recently advocated by researchers as potential solutions. However, irrespective of these technological advancements, manufacturing firms in the tool and die sector are still struggling to perform efficiently in the face of recurring operational disturbances. The paper identifies the most prevalent operational disturbances which occur in South Africa’s manufacturing firms in the tooling industry and their impact on business performance. A field study was conducted on a number of organizations which form an industrial cluster in the Western Cape manufacturing sector and seven typical disturbances were evaluated together with their root causes. The results gathered portrayed the correlation between identified disturbances and their corresponding consequences. The findings of the study were recommended to be used to develop models and computerized systems to solve the pending pandemic.
- ItemHolonic control system : a proposed solution for managing dynamic events in a distributed manufacturing environment(South African Institute for Industrial Engineering, 2014) Dewa, M. T.; Matope, S.; Van der Merwe, A. F.; Nyanga, L.ENGLISH ABSTRACT: Due to globalization, manufacturing of products is no longer a local activity done by a single company but rather a distributed venture as more firms are realizing the need to improve their flexibility and agility. The paradigm of e-manufacturing is gaining popularity among researchers and manufacturers who aim to improve their market share and shop floor visibility by belonging to larger collaborative networks. However, real-time events which lead to operational disturbances in a plant remain a challenge most manufacturers face since they result in deviation from initially prepared process plans and schedules, rendering them invalid before they can be launched on to the shop floor for implementation. The paper presents a Holonic Control System (HCS) as a proposed solution to managing this pandemic. The research focused on manufacturing firms in the Western Cape of South Africa which belong to the tooling industry. Cited in this paper are holonic architecture together with the success factors and barriers to implementing holonic control systems in South Africa. Results of the proposed system were generated by a simulation model and revealed that delivery time and resource utilization were improved by adopting the system.