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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Understanding the effects of different levels of product monitoring on maintenance operations : a simulation approach

Alabdulkarim, Abdullah A. January 2013 (has links)
The move towards integrating products and services has increased significantly. As a result, some business models, such as Product Service Systems (PSS) have been developed. PSS emphasises the sale of use of the product rather than the sale of the product itself. In this case, product ownership lies with the manufacturers/suppliers. Customers will be provided with a capable and available product for their use. In PSS, manufacturers/suppliers are penalised for any down time of their product according to the PSS contract. This has formed a pressure on the service providers (maintenance teams) to assure the availability of their products in use. This pressure increases as the products are scattered in remote places (customer locations). Authors have urged that different product monitoring levels are applied to enable service providers to monitor their products remotely allowing maintenance to be performed accordingly. They claim that by adopting these monitoring levels, the product performance will increase. Their claim is based on reasoning, not on experimental/empirical methods. Therefore, further experimental research is required to observe the effect of such monitoring levels on complex maintenance operations systems as a whole which includes e.g. product location, different types of failure, labour and their skills and locations, travel times, spare part inventory, etc. In the literature, monitoring levels have been classified as Reactive, Diagnostics, and Prognostics. This research aims to better understand and evaluate the complex maintenance operations of a product in use with different levels of product monitoring strategies using a Discrete Event Simulation (DES) approach. A discussion of the suitability of DES over other techniques has been provided. DES has proven its suitability to give a better understanding of the product monitoring levels on the wider maintenance system. The requirements for simulating a complex maintenance operation have been identified and documented. Two approaches are applied to gather these generic requirements. The first is to identify those requirements of modelling complex maintenance operations in a literature review. This is followed by conducting interviews with academics and industrial practitioners to find out more requirements that were not captured in the literature. As a result, a generic conceptual model is assimilated. A simulation module is built through the Witness software package to represent different product monitoring levels (Reactive, Diagnostics, and Prognostics). These modules are then linked with resources (e.g. labour, tools, and spare parts). To ensure the ease of use and rapid build of such a complex maintenance system through these modules, an Excel interface is developed and named as Product Monitoring Levels Simulation (PMLS). The developed PMLS tool needed to be demonstrated and tested for tool validation purposes. Three industrial case studies are presented and different experimentations are carried out to better understand the effect of different product monitoring levels on the complex maintenance operations. Face to face validation with case companies is conducted followed by an expert validation workshop. This work presents a novel Discrete Event Simulation (DES) approach which is developed to support maintenance operations decision makers in selecting the appropriate product monitoring level for their particular operation. This unique approach provides numerical evidence and proved that the higher product monitoring level does not always guarantee higher product availability.
242

Examining multinational corporations R&D subsidiaries embeddedness in multiple networks of knowledge

Batsakis, Georgios January 2013 (has links)
This research study elaborates on one of the most important features of the modern International Business (IB) area; the multinational R&D subsidiary. Taking into consideration the strategic importance and the particular role the R&D subsidiary plays, this study sheds light on the multiple forms of knowledge networks in which the R&D subsidiary is embedded. Accordingly, based on the two already known dichotomies of subsidiary knowledge networks (external home vs. external host and external host vs. internal) this thesis draws on the existing theory and empirical evidence and proposes a triangular view (i.e. external home, external host and internal) between the R&D subsidiary and its embeddedness within the surrounding knowledge networks. Accordingly, based on three major theories of the management in the IB area, Social Network Theory (SNT), Resource Dependency Theory (RDT) and Agency Theory (AT), this study provides answers on a number of under researched questions. First, what are the determinants of each type of R&D subsidiary embeddedness in each of the three available knowledge networks? Second, considering the relative costs influencing R&D subsidiaries to rely more or less on one form of embeddedness compared to another, what sort of relationship exists (i.e. complementary or substitutive) between the aforementioned forms of R&D subsidiary embeddedness? Finally, considering the contextual- and HQ-specific factors that impact the overall functioning of the R&D subsidiary, what sort of effect do the multiple forms of R&D subsidiary embeddedness have on the latter’s innovative performance? This study adopts a quantitative approach and employs appropriate econometric methods in order to provide answers to the aforementioned research questions. Furthermore, data from three different sources are amalgamated. First, a unique survey questionnaire is utilised. This instrument was originally developed in the University of Reading and corresponds to both subsidiaries and the HQ. The sample covers Fortune 500 Multinational Enterprises (MNEs). Second, and in order to augment the information derived from the survey, supplementary information on patent characteristics is sourced from the United States Patent and Trademark Office (USPTO) database. Third, a range of aggregate-level (secondary) data enriches the existing dataset. The findings reveal that each form of R&D subsidiary embeddedness is determined by a set of different predictors. Precisely, it is found that host location’s macroeconomic uncertainty positively influences subsidiary’s embeddedness in the home location’s knowledge network. Being an R&D subsidiary and having an adaptation and support-oriented profile, as well as being highly centralised to the HQ, negatively influences the R&D subsidiary’s embeddedness in the host location’s knowledge network. On the other hand, having a more research intensive and internationally integrated R&D role positively influences the R&D subsidiary’s embeddedness in the internal knowledge network of the MNE. The findings also indicate that a complementary relationship exists between external home and external host, as well as among external host and internal knowledge networks. On the contrary, a substitutive relationship is indicated between external home and internal networks under which the R&D subsidiary is embedded. Finally, as regards the last research question the results indicate that only internal embeddedness has a positive and significant impact on innovative performance, while scientific and research endowment of the host locations is also found to positively influence the innovative output of the R&D subsidiary. Implications for academics and practitioners (both managers and policy makers) are widely discussed and suggest that the three-dimensional view of embeddedness is useful in understanding and explaining the way MNEs’ foreign R&D subsidiaries operate.
243

The development of product design guidelines based on a new conceptual framework

Sethebe, Keaboka M. January 2012 (has links)
The work described provides the development, implementation and evaluation of engineering product design guidelines suitable for engineering product designers. The motivation arises from collaborative efforts that continue to be made by the Least Economically Developed Countries (LDC) and the Most Economically Developed Countries (MDC) towards the development of the engineering design field. It is argued here that product design guidelines which are derived from existing product design methods enhance the capability of engineering designers to shorten time to market, deal adequately with product design constraints and boost supply chains. The sample for the proposed study is comprised of companies in Botswana (a least economically developed country) and the United Kingdom (a most economically developed country). The research has been conducted using a mixed qualitative research approach comprised of aspects from the framework method, cluster analysis and Kolb's model. The findings have identified five themes central to the product design process which are incorporated into the engineering product design guidelines. Case study work was conducted to validate the approach. The following claims are made for contributions to knowledge: 1. A conceptual framework which is a graphical co-ordinate system of engineering and management techniques required by nine engineering product design methods. The conceptual framework is arranged according to two orthogonal axes that describe the structure of the product design process and incorporate the need function form structure, the divergent convergent structure, the product design drivers, product realisation process and product development lifecycles. 2. The product design method notation which is a register of the expressions derived from the conceptual framework and is used to communicate and aid in the selection of a group of techniques being implemented, or intended for implementation by design teams; and 3. The configuration scheme which provides a clear link between components, subassemblies, products, projects, programmes and policies. The critical point put forward by this work is that the conceptual framework is only comprehensible today because the engineering product design methods in the public domain have imparted knowledge about the functions of physical products (described here as part of the need function form structure) at the expense of human needs and the interactive forms of human responses to physical products. The contributions of this research provide a holistic and coherent means of integrating design methodologies for the benefit of design teams in Botswana. The approach is, however, universal and may also be beneficial for design projects in the most economically developed countries.
244

A systems thinking approach for modelling supply chain risk propagation

Ghadge, Abhijeet January 2013 (has links)
Supply Chain Risk Management (SCRM) is rapidly becoming a most sought after research area due to the influence of recent supply chain disruptions on global economy. The thesis begins with a systematic literature review of the developments within the broad domain of SCRM over the past decade. Thematic and descriptive analysis supported with modern knowledge management techniques brings forward seven distinctive research gaps for future research in SCRM. Overlapping research findings from an industry perspective, coupled with SCRM research gaps from the systematic literature review has helped to define the research problem for this study. The thesis focuses on a holistic and systematic approach to modelling risks within supply chain and logistics networks. The systems thinking approach followed conceptualises the phenomenon of risk propagation utilising several recent case studies, workshop findings and focus studies. Risk propagation is multidimensional and propagates beyond goods, finance and information resource. It cascades into technology, human resource and socio-ecological dimensions. Three risk propagation zones are identified that build the fundamentals for modelling risk behaviour in terms of cost and delay. The development of a structured framework for SCRM, a holistic supply chain risk model and a quantitative research design for risk assessment are the major contributions of this research. The developed risk assessment platform has the ability to capture the fracture points and cascading impact within a supply chain and logistics network. A reputed aerospace and defence organisation in UK was used to test the experimental modelling set up for its viability and for bridging the gap between theory and practice. The combined statistical and simulation modelling approach provides a new perspective to assessing the complex behavioural performance of risks during multiple interactions within network.
245

Utilisation of embedded information devices to support a sustainable approach to product life-cycle management

Kamal, Khurram January 2008 (has links)
The huge landfills from solid waste generated by the massive utilisation of different products from domestic sources are badly affecting the environment. About 70% of the solid municipal waste, two thirds of which comprises of household waste, is dumped as landflll all over the world. For efficient product lifecycle management via upgrade, maintenance, reuse, refurbishment, and reclamation of components etc., storage of product related information throughout its lifecycle is indispensable. Efficient use of information technology integrated with product design can enable products to manage themselves in a semiautomatic and intelligent manner. It means that products themselves should contain informationú that what to do with them when they are of no use. More advanced products may locate themselves and communicate with their recyclers through internet or some other communication technology. In this regard, different types of technologies have been investigated. These technologies are broadly classified as passive embedded information devices and active embedded information devices. Methods of automatic identification in combination with information technology can act as passive Embedded Information Devices (EID) to make products intelligent enough in order to manage associated information throughout their life cycles. Barcodes, Radio Frequency Identification tags, and a new technology called i-button technology were investigated as possible candidates for passive EIDs. The ibutton technology from the perspective of product lifecycle management is presented for the very first time in the literature. Experiments demonstrated that RFID and i-button technologies have potential to store not only the static but dynamic data up to some extent, such as small maintenance logs. As passive EIDs are unable to store the sensory data and detailed maintenance logs regarding a product, therefore, in addition to these demonstrators for passive EIDs, an advanced active EID demonstrator for lifecycle management of products with high functional complexity is also presented. Initially, the idea is presented as smart EID system that r~cords the sensory data of a refrigerator compressor and stores the detailed maintenance logs into the product itself. However, this idea is extended as intelligent EID that is implemented on a gearbox in order to predict the gearbox lifetime under an accelerated life test. This involves developmen,t of a novel on-chip life prediction algorithm to predict the gearbox lifetime under accelerated life testing scenario. The algorithm involves a combination of artificial neural networks and an appropriate reliability distribution. Results of accelerated life testing, simulation for the choice of appropriate reliability distribution and the life prediction algorithm are presented. Bi-directional communication software that is developed in order to retrieve lifecycle data from the intelligent EID and to keep intelligent EID updated is also explained. Overall, embedded information devices can be proposed as a good solution to support a sustainable approach to lifecycle management.
246

Supply chain network design under uncertainty and risk

Hollmann, Dominik January 2011 (has links)
We consider the research problem of quantitative support for decision making in supply chain network design (SCND). We first identify the requirements for a comprehensive SCND as (i) a methodology to select uncertainties, (ii) a stochastic optimisation model, and (iii) an appropriate solution algorithm. We propose a process to select a manageable number of uncertainties to be included in a stochastic program for SCND. We develop a comprehensive two-stage stochastic program for SCND that includes uncertainty in demand, currency exchange rates, labour costs, productivity, supplier costs, and transport costs. Also, we consider conditional value at risk (CV@R) to explore the trade-off between risk and return. We use a scenario generator based on moment matching to represent the multivariate uncertainty. The resulting stochastic integer program is computationally challenging and we propose a novel iterative solution algorithm called adaptive scenario refinement (ASR) to process the problem. We describe the rationale underlying ASR, validate it for a set of benchmark problems, and discuss the benefits of the algorithm applied to our SCND problem. Finally, we demonstrate the benefits of the proposed model in a case study and show that multiple sources of uncertainty and risk are important to consider in the SCND. Whereas in the literature most research is on demand uncertainty, our study suggests that exchange rate uncertainty is more important for the choice of optimal supply chain strategies in international production networks. The SCND model and the use of the coherent downside risk measure in the stochastic program are innovative and novel; these and the ASR solution algorithm taken together make contributions to knowledge.
247

Supply chain management for sustainable development : perspective from the Greater Pearl River Delta (China)

Tsoi, Joyce January 2006 (has links)
This thesis investigates the application and implications of supply chain management as a modern management model in regulating corporate outsourcing activities within the Greater Pearl River Delta. Globalisation has accelerated the application of supply chain management as a mechanism to enhance corporate performance. At the same time this rapid economic development has also accelerated the destruction of environmental and social conditions in these areas, and this has resulted in a lot of media and public attention. This thesis contributes to the debate on how principles and concepts of sustainable development can be put into modern business practice. Society also expects corporations to play an essential role in creating economic, environmental and social prosperity. The literature integrates the concepts of corporate social responsibility and environmental management into the core supply chain management activities within the wider framework of sustainable development. The environmental and social challenges are investigated since there is a growing recognition that development should go beyond economic growth. Whilst most research in the west has focused on the environmental approaches of supply chain management, this thesis seeks to understand, integrate, evaluate and find other options to improve conditions in suppliers’ factories. There is comparatively less literature discussing the social approach and implication to SCM with respect to this region. Perhaps more importantly social issues such as human rights and labour issues in relation to the physical environment are gaining momentum and are particularly important in this region because of strong media and western consumer pressure resulting from sweatshop activist group campaigns in the west. The four-tier methodological approach is structured within an action research model to achieve the research objectives. The first and second primary studies confirm that both suppliers’ and retailers’ knowledge are inadequate in terms of the establishing and publishing their environmental and social policies and procedures such as implementing internal and external controls for employees and workers. Their traditional and conservative mindsets is linked to their unwillingness to make a change despite the economic restructuring is rapidly taking and China’s accession into the WTO. In particular, codes of conduct is commonly existing literature embedded with environmental and social criteria as an important policy imposed by the multinational buyers to improve both environmental and social conditions within the supply chain. But how effective are such policies? Specifically, the effectiveness of the code of conduct approach is evaluated in the third study by social compliance audits at ground level in the garment industry. It is found that workers’ awareness of the code of conduct is low. The barriers include a lack of continuous training, human resources or systems present to tackle specific problems. Key challenges are found in the areas of excessive working hours, unfair pay to the workers and health and safety issues that coincide with the detailed interview results. This thesis concludes that the code of conduct approach is inadequate to improve workers’ conditions in the long term and asks what can be done next to contribute to the pursuit of sustainable development goals. The expert interviews from the fourth study explain the obstacles of the code of conduct approach. It is found that no long-term commitment and trust from multinationals is built on this relationship. The detailed interviews indicate that stakeholders’ approaches seem to be the most effective mechanism. In addition national government intervention in enforcing existing legislation and developing multi-party partnerships through trust programmes, whereby proper training from top management down to the workers and strong public involvement can help to achieve the desires long -term sustainability down the supply chain.
248

Investigation and development of an advanced virtual coordinate measuring machine

Hu, Yang January 2010 (has links)
Dimensional measurement plays a critical role in product development and quality control. With the continuously increasing demand for tighter tolerances and more complex workpiece shapes in the industry, dimensional metrology often becomes the bottleneck of taking the quality and performance of manufacturing to the next level. As one kind of the most useful and powerful measuring instruments, coordinate measuring machines (CMMs) are widely employed in manufacturing industries. Since the accuracy and efficiency of a CMM have a vital impact on the product quality, productivity and manufacturing cost, the evaluation and improvement of CMM performance have always been important research topics since the invention of CMM. A novel Advanced Virtual Coordinate Measuring Machine (AVCMM) is proposed against such a background. The proposed AVCMM is a software package that provides an integrated virtual environment, in which user can plan inspection strategy for a given task, carry out virtual measurement, and evaluate the uncertainty associated with the measurement result, all without the need of using a physical machine. The obtained estimate of uncertainty can serve as a rapid feedback for user to optimize the inspection plan in the AVCMM before actual measurement, or as an evaluation of the result of a performed measurement. Without involving a physical CMM in the inspection planning or evaluation of uncertainty, the AVCMM can greatly reduce the time and cost needed for such processes. Furthermore, as the package offers vivid 3D visual representation of the virtual environment and supports operations similar to a physical CMM, it does not only allow the user to easily plan and optimise the inspection strategy, but also provide a cost-effective, risk-free solution for training CMM operators. A modular, multitier architecture has been adopted to develop the AVCMM system, which incorporates a number of functional components covering CMM and workpiece modelling, error simulation, inspection simulation, feature calculation, uncertainty evaluation and 3D representation. A new engine for detecting collision/contact has been developed and utilized, which is suitable for the virtual environment of simulated CMM inspections. A novel approach has been established to calculate errors required for the error simulation, where the data are obtained from FEA simulations in addition to conventional experimental method. Monte Carlo method has been adopted for uncertainty evaluation and has been implemented with multiple options available to meet different requirements. A prototype of the proposed AVCMM system has been developed in this research. Its validity, usability and performance have been verified and evaluated through a set of experiments. The principles for utilising the AVCMM in practical use have also been established and demonstrated. The results have indicated that the proposed AVCMM system has great potentials to improve the functionalities and overall performance of CMMs.
249

The influence of supplier information sharing and information quality on strategic partnerships and internal lean practices among small to medium enterprises in South Africa

Sikhwari, Tina Mesmer 05 1900 (has links)
Tech. (Logistics, Faculty of Management Sciences), Vaal University of Technology / The focus of this study was to examine the relationship between information sharing, information quality, strategic partnership and internal lean practices among Small and Medium-sized Enterprises in South Africa. It is essential to understand practitioners’ and entrepreneurs’ current knowledge towards the topic at hand in order to determine what interventions would be most beneficial in helping to curb the problem of the lack of knowledge in this area and to understand the underlying causes behind the problem, while creating awareness and giving new insight to those who are already aware of this topic. Data was collected from a sample of 350 Small to Medium Enterprises and the measurement items in the measuring instrument were measured using a 5-point likert scale. Thereafter the collected data was coded and analysed by means of structural equation modelling using the AMOS 21 software package. The results indicate that supplier information sharing and information quality have a strong influence on strategic partnership and in turn strategic partnership has a strong influence on internal lean practices among Small to Medium Enterprises. This indicates that the level and quality of information shared between Small to Medium Enterprises and their suppliers has a positive effect on the strength of their partnerships as well as on the internal practices of each Small to Medium Enterprise. Based on these results, conclusions were drawn and recommendations were put forward on how internal lean practices in Small to Medium Enterprises can be improved by means of information sharing, information quality and strategic partnerships.
250

The influence of supply chain networks, flexibility and integration on the performance of small and medium enterprise in the Southern Gauteng region

Omoruyi, Osayuwamen January 2015 (has links)
D. Tech. (Business, Logistics, Faculty of Management Sciences), Vaal University of Technology / The South Africa economy has embraced the importance of small and medium enterprises (SMEs) as agents of economic growth and sustainability. However, for SMEs to be more efficient and effective towards the growth of the economy, it is important for SMEs to implement and take cognisance of the global competitive strategy among the so-called “best in class” organisations in order to also sustain and grow their business. The supply chain network with its flexibility has become the most commonly used business strategy worldwide for the improvement of performance in organisations, more especially among larger organisations. In today’s competitive environment, successful organisations are those that have been able to link their business functions within the organisation itself as well as across other businesses outside the organisation. Competitive challenges in the modern business environment have resulted in the need for organisation to integrate business processes strategically across other business units within the supply chain network. Network perspective theory, social network theory, network management theory and relational view theory are discussed to better understand the importance of SMEs supply chain network, flexibility and integration. The purpose of this study was to examine the influence of supply chain network, flexibility and integration on the SMEs business performance in the Southern Gauteng region. The research survey was conducted in the Meyerton, Vereeniging and Vanderbijlpark and 401 SMEs participated in the study. SPSS 22.0 was used to analyse the data and AMOS 22.0 was used to perform the confirmatory factor analysis. The structural equation modelling (SEM) was used to assess the proposed model fit and to test the statistically significant relationship of the hypothesis. The research study results revealed that supply chain network, flexibility and integration positively influence SMEs business performance. This study contributes new knowledge to the existing literature by providing a research framework that can enhance SMEs performance and also provide practical recommendations based on the research findings for SMEs and for future research. Furthermore, as one of the first studies addressing the influence of supply chain network, flexibility and integration on the performance of SMEs in the southern Gauteng region it has generated new insights and information as well as outlined the strategic reasons for SME owners and managers to improve on their business relationships. / VUT

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