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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.
61

QoS scheduling in integrated services packet-switching networks

Mabe, Kampong Jacob 27 August 2012 (has links)
M.Ing. / The Internet is evolving into a global communication infrastructure that is expected to support an overabundance of new applications such as IP telephony, interactive TV, and e-commerce. The existing best effort service is no longer sufficient. It is not enough to provide differentiated services and to meet QoS requirements of these different traffic types. As a result, there is an urgent need to provide more services that are powerful such as guaranteed services, flow protection etc, merged in one IP network, referred to as Integrated Services Packet-Switching Network (ISPN) in this thesis. To provide these services, QoS aware network architectures are required to implement the services. This dissertation presents a survey on two network architectures: Fair Queuing (FQ) and Scalable Core (SCORE), which attempt to provide QoS solutions in ISPN. We theoretically analyse scheduling as an important element in providing QoS in these architectures. The important thread in scheduling is performance and implementation complexity. SCORE based scheduling have less implementation complexity but cannot exactly match the high performance of FQ solutions, which suffer implementation complexity. The contribution of this work is a feedback protocol that minimises congestion in SCORE scheduling scheme called Core stateless fair queuing (CSFQ). The flow rates are adjusted by sending rate signal to a transmitting node from a receiving node, to adjust ill-behaved flow rate during congestion to a fair share rate of receiving node. We use CSFQ based theoretical analysis and simulations to demonstrate the performance of the feedback protocol.
62

The impact of quality assurance systems on the operational performance of laboratories

Ratsoeu, Ellen 30 May 2013 (has links)
M.Tech. (Operations Management) / It has become a trend for organisations to implement and certify quality systems. The most common quality system that organisations currently implement is ISO 9001. Certification to ISO 9001 has in recent times been used as a marketing tool to enter new markets. Nowadays, customers expect their suppliers and potential suppliers to be certified to ISO 9001. It has become a primary requirement for doing business, and customers now demand it. There have been various studies conducted to establish the advantages of ISO 9001 and its impact on organisational performance. Laboratories are no exception to this developing trend. They are implementing laboratory quality standards like ISO 17025 and the Organisation for Economic Cooperation and Development Good Laboratory Practice (OECD GLP). Some laboratories are now applying for certification of compliance to laboratory standards. Implementing and certifying laboratory systems is an exercise that comes at a cost. The exercise is demanding in terms of human resources, time and capital. There has not been a study conducted to evaluate the impact of these systems on the operational performance of laboratories. This is the reason that resulted in identification of the need to conduct the study. A qualitative research approach was pursued in conducting the study, where the researcher investigated the impact of laboratory quality standards on the operational performance of commercial and non-commercial laboratories. Operational performance in this study is defined as health and safety; supplier selection and performance; human resources; customer satisfaction and profitability. Data was collected through interviews, and was then summarised, and analysed in order to address the research problem. Based on the data collected, it was concluded there is no notable difference in the performance of laboratories with or without quality assurance systems such as ISO 17025 and OECD GLP.
63

An investigation of specific contributing factors affecting quality assurance in the diagnosis of conventional cervical smears

Jordaan, Suzette Mirietta January 2005 (has links)
The purpose of this study is to investigate specific contributing factors affecting quality assurance in the diagnosis of conventional cervical smears. More than half of South- African women fail to have one cervical smear in their lifetime and +/- 50 percent of those who do have cervical smears taken, are lost to follow-up. Since cervical cancer is the most common malignancy amongst women in developing countries, the medical profession will have to endeavor to screen a higher rate of women and ensure a 100 percent quality assurance with every patient treated in order to reduce the unacceptable high incidence of cervical carcinoma. At this stage it seems like an impossible task to screen all women in South Africa, due to far-off rural areas, shortage of medical professionals and the lack of knowledge of some women of the necessity of cervical smears. Many newly qualified South-African doctors leave the country to go and work elsewhere. South Africa then in turn has to recruit doctors from other countries to staff the State hospitals and clinics. Some areas have one doctor to thousands of patients, insufficient nursing personnel and inadequate equipment. Doctors in some areas cannot cope with the volume of work and the long hours. One has to accept that the quality of the management of some patients is affected negatively. There are a number of medico-legal issues (world wide) in relation to aspects of cervical cancer prevention practices which are controversial and are of particular concern to all of those involved in cervical cancer prevention. Various countries have therefore formed different national organizations to address the medico-legal issues in screening for the prevention of cancer. These organizations monitors procedures, internal quality control as well as external quality control. In South Africa, medico-legal cases are not so prevalent, but may become so shortly. The South-African medical professionals therefore have to ensure that their quality of work conforms to accepted good practice in all circumstances. State hospitals serve thousands of patients per month and it is an every day occurrence to see long queues of patients sitting waiting for doctors and who often have to come back the following day. The situation appears to be much improved in private practice and since patients have medical cover and accessible medical facilities. Since cervical cancer is the most common malignancy amongst women in developing countries, the medical profession will have to endeavor to screen a higher rate of women and ensure a 100 percent quality assurance with every patient treated in order to reduce the unacceptable high incidence of cervical carcinoma. At this stage it seems like an impossible task to screen 100 percent of women in South Africa, due to far-off rural areas, the shortage of medical professionals and ignorance of patients. Quality assurance is therefore of paramount importance to every medical professional for every patient treated. Laboratories all worldwide have been, or are in the process of being accredited by their specific accreditation authorities. The main reason for this is improvement of quality control and therefore quality assurance. The South African National Accreditation Society (SANAS) now accredits various laboratories in South Africa with the view of accreditting all laboratories within a certain time limit. The Ampath laboratory Port Elizabeth was successfully accredited during 2001. Accredited laboratories have to uphold a very high degree of quality to remain accredited. A team of professionals inspects the laboratory every 2 years and other quality assurance staff inspects the laboratories every few months. All aspects of the laboratory are checked, e.g. the qualification of staff, their registration with the Health Professions Council of South Africa (HPCSA), their curriculum vitaes, equipment, safety of the laboratory etc. Since the laboratory chosen for this study, is accredited, the author evaluated every cervical smear that was received in the laboratory since the year 2000, with the following objectives in mind: · Whether the presence or absence of an endocervical component has an effect on the adequacy of cervical smears · To determine the effect of using smaller coverslips on quality assurance in the cytology laboratory · Evaluate the effect that manual re-screening of smears has on quality assurance in the cytology laboratory. As there is a shortage of cytotechnologists and pathologists worldwide, several countries make use of automated screening devices as primary screening or secondary screening for quality assurance. These devices were tested in some laboratories in South Africa but were found to be very expensive and sensitivity and specificity were not up to standard. Sensitivity is a measure of the ability of a test to detect the abnormal - Sensitivity is the ratio of true positives to true positives + false negatives. Specificity is a measure of the ability of a test to correctly identify the negative - Specificity is the ratio of true negative to true negatives + false positives. The automated screening machines failed to identify abnormal cells amongst inflammatory cells, as well as in very blood stained smears. Several other problems also occurred and an increasing number of smears had to be manually rescreened, thus making this exercise costly and not helpful as a quality assurance instrument. The slides used for this thesis, have been retrieved from the archives of the Ampath laboratory in Port Elizabeth. Fourteen specific contributing factors affecting quality assurance in the diagnosis of cervical smears are also discussed and conclusions and recommendations given.
64

The perception of the quality of electrical engineering technologists and technicians by the electrical engineering industry.

Ntsandeni, Livhuhani Azwinndini. January 2010 (has links)
MTech. in Business Administration (MBA) / Universities of technology and institutions of technology produce electrical engineering technicians and technologists who expect to be employed in the electrical engineering industry. One of the reasons for a shortage of skills is the perception that the engineering industry has concerns regarding the quality of qualified students from universities of technology, because graduates struggle to meet the expectations of the industry. The industry expects them to possess basic skills, which can be utilised immediately. Technological advancement is ongoing and appears that the curricula of tertiary institutions are not keeping abreast of changes. This study aims to establish the perception of the engineering industry of the quality of electrical engineering graduates leaving universities of technology in order to evaluate their employability. Universities of technology should regard industry as their main client, supplying firms with the type of product they need.
65

Quality of service support for progressive video transmission over Internet

Kim, Minjung 01 December 2003 (has links)
No description available.
66

Product quality modeling and control based on vision inspection with an application to baking processes

Zhang, Yingchuan 14 April 2005 (has links)
Manufacturing industries are facing major challenges in terms of improving product quality and increasing throughput while sustaining production costs to acceptable levels. Product-oriented processes, both legacy and new, are poorly monitored and controlled on the basis of distributed loop controllers that are aiming to maintain critical process variables within acceptable bounds. Thus, poor quality product results when such processes are subjected to large disturbances - operational failures, environmental changes, and changes in loading conditions. In this research, product quality modeling and control based on a vision inspection methodology is proposed to improve product quality and increase productivity. The main contributions of this research are twofold. First, this research introduces a product quality modeling methodology that combines both physical-based modeling and data-driven modeling. The quality model is the link between information coming from the inspection of product features and the specification of process control strategies. It is essential to control and optimize the process. Physical-based modeling is used to model the product temperature profile, and data-driven modeling is used to train the mapping from the product temperature profile to each quality metric. The break down of the sub models increase the flexibility of model development and reduce the effort to change the model when the quality metrics change. The second contribution is the development of a novel approach to control product quality based on vision inspection, which is developed as part of a hybrid, hierarchical architecture. The high-level control module involves scheduling of multiple plant processes, diagnostics of the failure condition in the process, and the supervision of the whole process. The mid-level control module, which is the focus of the work presented here, takes advantage of baking product quality indicators and oven parameter measurements to optimize zone temperature and conveyor speed set points so that the best product quality is achieved even in the presence of disturbances. The low-level control module consists of basic control loops. Each of them controls parameters of each operation in the process separately. They are generally simple and easy to implement.
67

Quality assurance framework for small manufacturing companies in the clothing industry in the Cape Metropolitan area

Norton, Ingrid January 2007 (has links)
Thesis (MTech (Business Administration))--Cape Peninsula University of Technology, 2007 / An assessment undertaken by the Clothing and Textile Centre in the Western Cape (Clotex) during 2002 revealed that there was a great need for quality in the clothing sector. Furthermore, the research undertaken by the Department of Science and Technology (2004) supports and recommends the development of simple, paper-based systems for implementation and measurement for quality and production systems. An analysis of the macro- and micro-environmental factors confronting the clothing industry revealed that substantial pressure was placed on the clothing industry due to unfavourable exchange rates, increased pricing and illegal imports. The result has been a decline in sales, profits and exports, which has lead to the closure of many clothing companies in the Western Cape during the period 2003 to present. Furthermore, this has resulted in the increase of SMME companies that have been established due to the increase in unemployment. A combination of qualitative and quantitative research techniques was applied during this study, namely focus-group sessions and survey questionnaires. Six focus-group sessions were held with participants from the retail sector, large manufacturers and small manufacturers with the purpose to establish the quality needs in the clothing industry and the type of quality systems utilised. The outcome of the focus group was the development of a questionnaire, using both a combination of scale response questions as well as dichotomous questions. As a result a research survey was conducted amongst the small manufacturing companies in the Western Cape who conform to the provisions contained in the National Business Act, 1996 (Act 102 of 1996). The research revealed that all the respondents had implemented quality control systems. Quality control systems are viewed as preventative systems in ensuring that goods not conforming to customer specifications are prevented from reaching the customer. The research analysis further revealed that communication between buyer and seller was an integral part of the success of the business. The research provides small-business with a framework, which will facilitate the evaluation of the current quality practices with the view to improving or implementing an effective quality assurance system.
68

Quality prediction and control of continuously cast slabs

Camisani-Calzolari, Ferdinando Roux 24 January 2008 (has links)
Please read the abstract (Summary) in the section, 00front of this document / Thesis (PhD (Electronic Engineering))--University of Pretoria, 2008. / Electrical, Electronic and Computer Engineering / PhD / unrestricted
69

Velocity, defect rate and pacing strategy in simulated inspection

Lin, Ming-Jeng January 2011 (has links)
Digitized by Kansas Correctional Industries
70

Acceptance sampling: a focus on attributes versus variables sampling

Sud, Krishen Kumar. January 1976 (has links)
Call number: LD2668 .R4 1976 S93

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