Thesis (MSc)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: This study was initiated in October 2004 when Vizier Systems (Pty) Ltd approached the Department of Industrial Engineering at the University of Stellenbosch with a concept. They proposed that a fruit packing line be represented as a series of unit operations and suggested that the concept could be used to create a generic model that can be used to represent any packing line. After further discussions with Vizier about the concept and their reasons for requiring a generic model, a formal client requirement was formulated. It was decided that the generic modelling concept had to be tested in the citrus industry. Modelling theory was investigated and a generic modelling methodology was formulated by adapting an existing modelling methodology. The first few steps of the developed methodology led to industry data being gathered and several role-players in the citrus export industry being visited. An analysis of the data enabled the development of the necessary techniques to do distribution estimation and forecasting of the system input, which is fruit. The various processes were grouped into generic groups and detailed capacity calculations were developed for each process. The fruit parameter estimation techniques and capacity calculations were integrated into a five step modelling procedure. Once the generic model was set up to represent a specific packing line, the modelling procedure provided optimum flow rates, equipment setups and personnel allocations for defined production runs. The modelling procedure was then translated into a computer model. This allowed a complete capacity analysis of a packing line by incrementally varying the characteristics of the fruit input. The developed generic model was validated by comparing its predictions to the results of two production runs at an existing packing line. It was found that the generic model is able to adequately represent the packing line and that the fruit inputs and outputs can be accurately estimated. The concept proposed by Vizier, that a packing line can be generically modelled as a series of unit operations, was shown to be valid. / AFRIKAANSE OPSOMMING: Hierdie studie is in Oktober 2004 geïnisieer toe Vizier Systems (Pty) Ltd die Departement van Bedryfsingenieurswese aan die Universiteit van Stellenbosch met ’n konsep genader het. Hulle het aan die hand gedoen dat ’n vrugtepaklyn voorgestel kan word as ’n reeks eenheidsprosesse en dat die konsep gebruik kan word om ’n generiese model te skep om enige vrugtepaklyn te verteenwoordig. Na verdere samesprekings met Vizier oor die konsep en hul redes vir die noodsaaklikheid van ’n generiese model, is ’n formele kliëntebehoefte geformuleer. Daar is besluit dat die generiese modelleringskonsep in die sitrusbedryf getoets gaan word. Modelleringsteorie is ondersoek en ’n generiese modelleringsmetodologie is geformuleer deur ’n bestaande modelleringsmetodologie aan te pas. Die stappe van die ontwikkelde metodologie het gelei tot die insameling van data vanuit die industrie en verskeie rolspelers in die sitrus-uitvoerindustrie is besoek. ’n Analise van die data het die ontwikkeling van die tegnieke moontlik gemaak wat nodig was om verspreidingsberamings en voorspelling van die stelselinset – die vrugte – te doen. Die onderskeie prosesse is gegroepeer in generiese groepe en gedetailleerde kapasiteitsberekeninge is vir elke proses ontwikkel. Die vrugparameter beramingstegnieke en kapasiteitsberekeninge is geïntegreer in ’n vyf-stapmodelleringsprosedure. Nadat die generiese model opgestel is om ’n spesifieke paklyn voor te stel, het die modelleringsprosedure optimum vloeitempo’s, toerustingopstellings en personeeltoedelings vir die spesifieke produksielopie gegee. Die modelleringsprosedure is toe herlei tot ’n rekenaarmodel. Dit het ’n volledige kapasiteitsanalise van die paklyn moontlik gemaak, deur die eienskappe van die vruginset inkrementeel te varieer. Die ontwikkelde generiese model is gestaaf deur sy voorspellings te vergelyk met die resultate van twee produksielopies van ’n bestaande paklyn. Daar is bevind dat die generiese model in staat is om die paklyn voldoende voor te stel en dat dit die vruginsette en -uitsette akkuraat kon beraam. Die geldigheid van die konsep wat voorgestel is deur Vizier, naamlik dat ’n paklyn generies gemodelleer kan word as ’n reeks eenheidsprosesse, is bevestig.

Lifting and overstraining are major causative factors related to musculoskeletal injuries and low back pain. A great number of work-related injuries arise from the handling and/or mishandling of materials. Hence there is a need to quantify risk factors in situ and develop guidelines for safe lifting practises in industry. The aim of this study was to make appropriate in situ quantification, within a commercial warehouse, of the stresses and physical demands imposed on the worker when performing two handed lifts in the sagittal plane. The performance of employees was assessed under normal working conditions through an observational methodology of data collection. Task performance evaluation was based on detailed measurement of all containers handled, an activity and time analysis, and the 'Work Practices Guide to Manual Lifting’ (NIOSH, 1981) which was used as the primary guide to developing theoretical recommendations to probable MMH risk factors for the workers involved. Of the 191 tasks analysed 103 were deemed unsuitable. Appropriate task factor adjustments were made where necessary to both the frequency and Hfactors (horizontal distance between the centre of gravity of the container and that of the worker) in order to reduce the risk factor for the workers

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Small and medium toilet manufacturing businesses in Peru face significant problems such as low productivity because of a high rate of production losses. To address this issue, the present study proposes the application of a lean manufacturing technique, such as the Poka-Yoke model, which improves the production flow within the company by implementing a transportation cart with a safety system to help reduce material falls during the manufacturing process. The results showed a 24% increase in productivity and reduction in problems of damaged products that did not meet quality standards, thus preventing their subsequent reprocessing. / Revisión por pares

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This report discusses the major functions, decisions, and strategies of automated storage and retrieval systems (AR/RS). The report surveys the essential features of expert systems and discusses how they can be applied in automated warehousing environments. A blackboard expert system architecture was examined and found to be a flexible and responsive control system for automated warehousing applications. A simple AR/RS expert system was constructed using an expert system software package. A warehousing simulation was performed which compared the expert system’s performance to a typical AR/RS control system. The expert system produced increased efficiency of operation because of the intelligent rules programmed into the system.

Miljöcertifieringssystemet för byggnader, LEED (Leadership in Energy &Environmental Design) lanserades 1998 i USA av USGBC (United States GreenBuilding Council). USGBC är en icke vinstdrivande organisation, vars mål är attbidra till utökat hållbart byggande. Skanskas första byggnad som certifieradesenligt LEED färdigställdes 2001 i den amerikanska delstaten North Carolina. Islutet av februari 2009 offentliggjordes det att Skanska skall införa systemet i sinNordiska organisation.Undersökningen som genomförts handlar om ett av LEED New Constructions sexdelområden, Materials & Resources. Materialhanteringen för ett byggprojekt somSkanska uppfört har analyserats för att avgöra huruvida det skulle kunna erhållapoäng vid en certifiering enligt LEED. Metoden för undersökningen har varitsamtal med materialleverantörer och medarbetare från Skanskas organisation somvarit delaktiga i byggprojektet. Material som använts för undersökningen är LEEDfor New Construction Version 2.2 och projektdokumentation av olika slag. Enligtvår undersökning skulle det byggprojekt som vi analyserat kunnat erhålla tre avtotalt 13 poäng vid en certifiering. / The environmental certification system for buildings, LEED (Leadership inEnergy & Environmental Design) was launched in 1998 by USGBC (UnitedStates Green Building Council). USGBC is a non-profit organization aiming foran expansion of sustainable building practices and education. The first ofSkanska’s buildings to be certified according to LEED standards was finished inNorth Carolina in 2001. By the end of February 2009 Skanska made public thatthe system was to be adopted in their Nordic organization.This study examines one of LEED New Construction’s six subcategories,Materials & Resources. The materials handling of a Skanska construction projecthas been analyzed to determine whether it could receive credits if certifiedaccording to LEED. The method used has been verbal contact with materialsuppliers and Skanska staff involved in the construction project. The theoreticalbasis has mainly been LEED for New Construction Version 2.2 and several kindsof project documentation. It is concluded in this study that the construction projectanalyzed could have received three of a total of 13 credits if certified.

A Material Management Decision Support System is applied to a case study distribution facility. The system is formulated within the framework of an algorithm that consists of two primary steps. The first step utilizes a simulation model to analyze the impact of three management policies that implement material handling equipment in the distribution facility. The simulated results of each policy represent a database of performance measure values. The second step utilizes a decision model to evaluate the set of policy alternatives. In this step, the user is required to rank order and assign relative weights to decision parameters. A value function is computed for each alternative using this information, the simulated performance measures and non-model parameters. Output for the model is in terms of rank ordered numerical worths that designate the final selection alternative based on the decision maker's preferences. / Master of Science

Construction has multiple material handling equipment that cross each others’ paths. These equipments have significant dynamic behavior under various load conditions. A system to model multi-tasking material handling with dynamic behavior capabilities will provide advances in automation. Current computer graphics and CAD technology, combined with advanced engineering concepts provide the capability for a dynamic behavior modeler which is capable of modeling the dynamics of mechanisms involved in the material handling operations in construction realistically. This thesis presents a conceptual dynamic behavior modeler. The conceptual modeler is envisioned for future inclusion into a multi-tasking motion planning system for material handling in construction. The conceptual modeler is intended to perform dynamic simulation of 3-D rigid bodies for computer animation. In addition, the modeler provides a capability to model and predict real-life behavior of physical objects subject to dynamic loading. This thesis also presents a sample animation case involving a mobile crane in a "pick and place task”. Although traditional animation methods have been employed for the sample case, the animation provides an insight to the realistic visualization that would be achieved through dynamic simulation. In order to achieve a real-time animation, no finite element modeler has been utilized. Also, significant work was done to study approximation Strategies in the development of the analytical model of the sample case to improve the efficiency of the animation. The dynamic behavior modeler presented in this thesis will provide a novel approach to model the motion planning process. The modeler will ensure realistic visualization of material handling operations. The modeler will allow engineers to animate the material handling process based on dynamic simulation. Engineers will be able to realistically model critical rigging operations. The technology provided by the dynamic behavior modeler will enable engineers to better plan, model, and control the material handling process. This will further lead to significant improvements in constructability and overall performance of construction projects. / Master of Science

The nature of how an Automatic Storage & Retrieval System stacker crane moves through the aisle, between picking and storing operations, is analyzed through a simulation model. A continuous SLAM model simulates the performance of a single aisle Automatic Storage & Retrieval System stacker crane under various control conditions. Crane speed, acceleration rate, job arrival rate, and discrete or continuous interrupt sensing are the variables examined within the model. The performance level of the system is observed while altering the control. / M.S.

The overall objective of this research is the development of a set of guidelines, or constructs, which will assist in the formulation of a simulation language for bulk material transportation systems. The formulation of these guidelines necessitated a thorough analysis of two particular areas; these being the simulation analysis procedure and bulk material transportation systems. For comprehension of the nature of simulation languages, Part II presents each step of the analysis procedure as examined from the language's perspective. Supporting this analysis, Part III presents a detailed review of selected simulation languages which are currently available to the systems analyst. Bulk material transportation systems are presented in Part IV. These systems are discussed in detail from the viewpoint of the mode of transportation, the transportation medium, and the type of bulk materials transported. The functional specifications, or constructs, for a bulk material transportation simulation language are presented in Part V. These specifications are categorized according to the following areas; the system being described, the language form, and computer considerations. Utilizing these constructs a simulation language may be developed for subsequent use by bulk material transportation systems analysts which shall be a more appropriate choice for simulating their systems than any language currently available to them. / M.S.