Thesis (Ph.D.)(Industrial and Systems Engineering))--University of Pretoria, 2006. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

This study explores the history of a group of London handicraftsmen, the multi-skilled millwrights, who were power-transmission mechanics and rudimentary engineers, from 1775-1825. It reveals an organised group of old-style journeymen, who had developed a powerful grip on all aspects of the trade itself, not just their terms and conditions (which were in the top bracket of London artisans of the time). This amounted to a power-sharing partnership with their masters who accepted this arrangement for decades of the late eighteenth century because of the millwrights' unique skills, quality work and organised power as a trade club. The millwrights as individual handicraftsmen varied from 'rough and ready rule of thumb' mechanics to ingenious mechanical and civil engineers. Many of these latter could design and erect complex buildings and infrastructure for water, wind or horse-driven mills and install the transmission millwork/gear wheels of the time. They were, in effect, a powerful guild to which many of the masters belonged. With the growing demand for larger and more complex power sources of the early industrial revolution, this traditional trade came under tremendous pressure to overcome the restrictions imposed by the journeymen millwrights, especially from the businesses who employed the masters as contractors. The study examines the previously unappreciated role of the London brewers, distillers and other manufacturers in pressurising the master millwrights to resist the power of their combined journeymen. It was this pressure which induced the master millwrights to bring to Parliament a Combination Bill seeking to outlaw the London Society of Journeymen Millwrights' trade club and replace them by wage regulation of the magistrates of the City and neighbouring Home Counties. This wider development is examined in detail. Those City employers were also prominent in the more successful 1812-14 bid to remove the medieval apprenticeship laws which then underpinned all journeymen's control of skilled labour supply. But it was the exigencies of the wars with the French from the 1800s which really drove the technological changes which undermined the millwrights' exclusive control of mechanical work, especially using the new, better quality fabrication of iron and machinery. This development is examined at the Portsmouth naval dockyard in 1805 and the spread of new engineering works in the London area thereafter. A new breed of engineering employer now emerged who were successful in breaking the millwrights' grip on the trade with greater control in larger establishments. They made a practice of employing/training non- or short-apprenticed skilled fitters, turners and a variety of other specialised engineering workers to do aspects of the more expensive and less tractable high-skilled millwrights with what became known as an Engineers' Economy. This little-known episode of early British engineering history was illustrated throughout with contemporary prints and drawings and pen-pictures of the key figures who became involved - John Rennie, James Watt and Henry Maudslay, to name but a few. An update and rewrite has recently been produced entitled, The Old London Artisans: the Millwrights 1775-1825.

Master of Science / Department of Industrial & Manufacturing Systems Engineering / David H. Ben-Arieh / In present competitive market, there is growing concern for ascertaining and fulfilling the individual customer’s wants and needs. Therefore, the focus of manufacturing has been shifting from mass production to mass customization, which requires the manufacturers to introduce an increasing number of products with shorter life span and at a lower cost. Also, another challenge is to manage the variety of products in an environment where demands are stochastic and the lead times to fulfill those demands are short. The focus of this thesis is to develop and investigate platform based production strategies, as opposed to producing each product independently, which would ensure the economic production of the broader specialized products with small final assembly time and under demand uncertainty. The thesis proposes three different platform based production models. The first model considers the economic production of products based on a single platform and with forecasted demands of the products. The model is formulated as a general optimization problem that considers the minimization of total production costs. The second model is the extension of the first model and considers the production of products based on multiple platforms and considers the minimization of total production costs and the setup costs of having multiple platforms. The third model is also an extension of the first model and considers the demands of the products to be stochastic in nature. The model considers the minimization of total production costs and shortage costs of lost demands and holding cost of surplus platforms under demand uncertainties. The problem is modeled as a two stage stochastic programming with recourse. As only the small instances of the models could be solved exactly in a reasonable time, various heuristics are developed by combining the genetic evolutionary search approaches and some operations research techniques to solve the realistic size problems. The various production models are validated and the performances of the various heuristics tailored for the applications are investigated by applying these solution approaches on a case of cordless drills.

Master of Science / Department of Industrial & Manufacturing Systems Engineering / Todd W. Easton / Integer programming (IP) has been and continues to be widely used by industries to minimize cost and effectively manage resources. Faster computers and innovative IP techniques have enabled the solution to many large-scale IPs. However, IPs are NP-hard and many IPs require exponential time to solve. Lifting is one of the most widely used techniques that helps to reduce computational time and is widely applied in today's commercial IP software. Lifting was first introduced by Gomory for bounded integer programs and a theoretical and computationally intractible technique to simultaneously lift sets of variables was introduced by Zemel in 1978. This thesis presents a new algorithm called the Maximal Simultaneous Lifting Algorithm (MSLA), to simultaneously uplift sets of binary integer variables into a cover inequality. These lifted inequalities result in strong inequalities that are facet defining under fairly moderate assumptions. A computational study shows that this algorithm can find numerous strong inequalities for random Knapsack (KP) instances. The pre-processing time observed for these instances is less than 1/50th of a second, which is negligible. These simultaneously lifted inequalities are easy to find and incorporating these cuts to KP instances reduced the solution time by an average of 41%. Therefore, implementing MSLA should be highly beneficial for large real-world problems.

Master of Science / Department of Industrial & Manufacturing Systems Engineering / Malgorzata J. Rys / Emergency Medical Systems (EMS) are designed to handle emergencies. Fortunately, most emergencies faced have only one patient. The every day system is not designed to respond to emergencies in which there are many casualties. Due to natural disasters and terrorist attacks that have occurred over the past decade, mass-casualty disaster response plans have become a priority for many organizations, including EMS. The resources available for constructing such plans are limited. Physical simulations or practices of the plan are often performed; however, it is not until a disaster strikes that the capabilities of the plan are truly realized. In this paper, it is proposed that discrete-event simulations are used as part of the planning process. A computer simulation can test the capability of the plan under different settings and help planners in their decision making. This paper looks at the creation of a discrete-event simulation using ARENA software. The simulation was found to accurately simulate the response to the Greensburg tornado that occurred May of 2008. A sensitivity analysis found that the simulation results are dependent upon the values assumed for Volunteer Injury Rate, Injury Level, Information Dissemination Rate and Transportation Decision variables. When a disaster occurs, the local resources are overwhelmed and outside aide must be called in. Decision rules for when to request more outside ambulances and when to release them to send them home are evaluated. The more resources that are made available, the quicker patients receive medical care. However, when outside ambulances are called in, they are putting their home area at risk because it no longer has complete (or any) ambulance coverage. As the percent of coverage decreases, the amount of time that victims spend waiting for ambulances also decreases. Many decision rules were evaluated, resulting in various combinations of ambulance wait times and average percent coverage. It is up to Disaster Planners to determine how much of an additional wait can be assumed by the disaster victims to prevent outside districts from taking on unwarranted risk of low coverage.

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