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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.
571

Love or protection? : defining and measuring maternal-fetal attachment from the woman's perspective

Sandbrook, Sandra January 2009 (has links)
Existing commonly used maternal-fetal attachment instruments have not been thoroughly tested for reliability and validity; criticism can be levelled for a variety of problems ranging from lack of reliability due to an inadequate underpinning framework to facilitate objective interpretation to limited generalizability due to the sample. The aim of this study is to acknowledge the centrality of the mother, to use the experiences of pregnant women to generate a definition of maternalfetal attachment and ultimately create a tool that will act as a reliable, valid and simple measurement. A mixed method framework utilising a sequential exploratory strategy has allowed qualitative exploration of the phenomenon under investigation followed by quantitative testing of the emerging theory on a much larger and different sample. Phase 1 involved face to face open structured interviews on an opportunity sample of 10 (5 primigravid; 5 multiparous) women in the final trimester of pregnancy followed by 3 focus groups targeting specific groups – primigravid women (6 participants); multiparous women (7 participants) and teenagers (4 participants). Data analysis was through constant comparative methodology. A multidimensional, psycho-biological definition of attachment was generated from the women’s own perception of their attachment to their fetus. This was used as a framework to design a questionnaire for the measurement of maternal-fetal attachment. Phase 2 involved the validation of the questionnaire and further testing of the definition. Cohort 1 tested for reliability with 200 participants within their second or third trimester of pregnancy. Following modification of the questionnaire, Cohort 2 a sample of 150 women within the final trimester of pregnancy tested the tool for internal reliability and validity. The generated Maternal-Fetal Attachment Tool (MFAT) following rigorous testing proved both reliable and valid. Maternal fetal attachment is founded in psycho-biological theory and is a complex multi-dimensional construct. Central to the definition is the woman’s need to protect her fetus, attachment develops as the fetus becomes more tangible, it is facilitated through the woman’s intergenerational experience of attachment and through appropriate social support. Maternal-fetal attachment facilitates behavioural change to ensure a favourable intra-uterine environment.
572

A manufacturing strategy: fuzzy multigoal mathematical programming to the Stanely cordless power tools

李沛雄, Lee, Pui-hung, Johnelly. January 1993 (has links)
published_or_final_version / Business Administration / Master / Master of Business Administration
573

Condition monitoring of machine tools and machining processes using internal sensor signals

Repo, Jari January 2010 (has links)
<p>Condition monitoring of critical machine tool components and machining processes is a key factor to increase the availability of the machine tool and achieving a more robust machining process. Failures in the machining process and machine tool components may also have negative effects on the final produced part. Instabilities in machining processes also shortens the life time of the cutting edges and machine tool.</p><p>The condition monitoring system may utilise information from several sources to facilitate the detection of instabilities in the machining process. To avoid additional complexity to the machining system the use of internal sensors is considered. The focus in this thesis has been to investigate if information related to the machining process can be extracted directly from the internal sensors of the machine tool.</p><p>The main contibutions of this work is a further understanding of the direct response from both linear and angular position encoders due the variations in the machining process. The analysis of the response from unbalance testing of turn tables and two types of milling processes, i.e. disc-milling and slot-milling, is presented. It is shown that operational frequencies, such as cutter frequency and tooth-passing frequency, can be extracted from both active and inactive machine axes, but the response from an active machine axis involves a more complex analysis. Various methods for the analysis of the responses in time domain, frequency domain and phase space are presented.</p> / QC 20100518
574

Assessment of service lives in the design of buildings

Marteinsson, Björn January 2003 (has links)
<p>The built environment usually constitutes a very importantpart of the real capital of a nation and the constructionsector represents more than 10% of the yearly Gross NationalProduct of the industrialised world. The importance of goodplanning of all construction, where the service life of thework is considered, is of great interest and an importantaspect in sustainability considerations. The need for increasedknowledge about degradation of materials, for structuredmethodology, and for working tools for those involved in theplanning process, has resulted in an extensive effort inpre-normative research and standardisation regarding thisfield.</p><p>This thesis presents a discussion on service life planningand the role of the Factor Method in such a work, andespecially, discussion of modification and development of themethodology. In the design process, the need to evaluate theservice life of products is great, and this is a formidableproblem to solve, as the results will depend on both materialproperties and the environment in which the material is placedor used. A practical solution has to be based on a goodknowledge in the field, but also on a sound working strategy,to ensure that different design scenarios can be compared in astandardised or structured way. The Factor Method is apromising working tool for such an evaluation and comparison,but is as such, still more of a methodology, than a method.Examples of the use of the methodology are still very limitedand the method as such, is much discussed by researchers.However, its future will depend on how practical it will be toapply in use. The method is useful to estimate the service lifeof products, based on a known reference service life and anumber of modifying factors that will depend on the conditiondifferences between the specific project and the referencein-use conditions. The required precision of such a methodologyis discussed, especially in the light of inherent distributionin material properties and the fact that often the consequencesof failure are very limited. In such cases, the standardisedFactor Method is considered to be of great use and should giveparties involved a good means for working in a structured andsystematic way.</p>
575

Interactive Web-based Visualization Tool to Support Inquiry-based Science Learning

Johansson, Emil January 2010 (has links)
<p>This thesis introduces the idea of an interactive web-based visualization tool to support inquiry-based science learning. The problem that occurs when the teachers and students are discussing the collected data is that they are lacking a tool to display such large quantities of data. It is often hard to fully understand such data. This education tool makes use of different visualization approaches in order to support students while getting insights from their collected data. In this thesis I proposed and implemented an interactive web-based visualization tool that was used at a prototype level during the educational activities. The requirements and user needs led the development of this prototype. Requirement elicitations have been done as a part of the research project conducted by CeLeKT.</p><p> </p><p>For the development of this tool, it was necessary for the input of the teachers and students in order to get an understanding of the requirements. The initial inquiry of the teachers and students show the necessity and usefulness of an interactive web-based visualization tool to support learning practices.</p>
576

Discounts as a marketing tool for attraction and retention of customers in e-commerce through the example of a comparative analysis of the specificity of fashion e-shops in Russia and Sweden

Ilicheva, Elena January 2015 (has links)
This study provides a comparative analysis of pricing promotions, which create an incentive to buy in Russian and Swedish fashion e-shops. The aim of this work is to determine the national differences in sales promotions used in e-commerce in these countries. This work confirms the existence of modern marketing trend in the e-commerce, which uses discounts as a tool for communication with consumers and for retaining them in the shop as a regular customer, and not just for traditional use of discounts as a way to sell remaining goods. To conduct the study the collected data obtained through systematic observation of application of discounts and promotions as marketing tools in the e-shops in these countries. Following the comparative analysis of statistical data we were able to determine the difference in the periods of sales, the maximum and minimum level of price falls, to create a typology of discounts, typical for both countries and for each of them separately. The recommendations for online retailers who develop the markets of these countries with regard to national specifics in communication with the consumer and based on the most popular types of discounts and promotions are also the important part of this work. The results of this study refute the words of the expert Simonetta Carbonaro that the modern approach to pricing policy in the e-commerce is a "suicide of fashion retail."
577

台灣工具機廠商教育訓練績效分析-模糊資料包絡分析法之應用

陳宥翔 Unknown Date (has links)
工具機不僅在機械產業占有一席之地,在製造業更是扮演舉足輕重的 角色,生活周遭所使用的物品,許多都是由工具機所製造。工具機產業的 核心技術,仰賴資深員工的經驗傳承,因此教育訓練是工具機廠商營運的 流程中重要的一環。傳統DEA 要求所有的投入、產出資料必須為量化的數 據,然而現實生活中有很多重要的變數難以量化,Likert 量表發明後,學 者們大量使用Likert 量表量化這些變數,但是Likert 量表尺度的公平性 是許多學者質疑的重點。模糊DEA 透過模糊理論,改善Likert 量表尺度 公平性的問題,因此本研究使用模糊DEA 進行工具機廠商教育訓練績效的 分析,並比較Likert 量表尺度下的DEA 與模糊DEA 實證結果的不同,研 究對象為民國96 年的台灣地區85 間工具機廠商。 幾項重要的實證分析結果如下: 1. 整體技術效率差者,多為訓練積極的廠商。 2. 部分規模效率差的廠商,純技術效率表現尚在中等水平,表示這些廠商 只是因為訓練較為積極,使得投入在生產規模遞減的水準。 3. 工具機產業的教育訓練普遍有浪費的現象,顯示只要投入少許資源即可 達到相當的成效,若要突破某個瓶頸,就要增加相當多的資源。 4. 整體而言使用Likert 量表尺度或是模糊DEA 的結果沒有顯著差異,但 是對於效率較佳的廠商來說,模糊DEA 具有較高的鑑別力。 / The machine tool plays an important role in not only machinery industry but also the whole manufacturing industry. Most of goods around us are made by the machine tool. The core technologies hold by experienced employees depends on training to pass down. Therefore, training is an essential process in machine tool factories. In traditional DEA, all inputs and outputs need to be numeric data. But in reality, there are many key variables are hard to be measured in numeric. After Likert scale being invented, the scholars widely use the scale to evaluate these key variables. However, there is criticism of the equity in Likert scale. Fuzzy DEA corrects this disadvantage of Likert scale with fuzzy theory. As a result, this study evaluates the training efficiency of 85 Taiwanese machine tool manufacturers in 2007 with fuzzy DEA and comparers the result between fuzzy DEA and the method of Likert scale. Some important conclusions are shown as follow: 1. Most of the inefficient DMUs are active about training. 2. Although some DMUs are bad in scale efficiency, they are fair in pure technical efficiency. It explains that these DMUs just input at decrease return to scale (DRTS) level. 3. Generally, there is waste of training in this industry. The empirical result tells us they can obtain certain effects with little input. If they want to break through some bottle neck of training effects, they have to input tremendous resources. 4. As a whole, there is no difference between the result of fuzzy DEA and the method of Likert scale. However, there is better discrimination of efficient DMUs in fuzzy DEA.
578

Pictionary Physics: En kvalitativ undersökning av ett didaktiskt verktyg i enlighet med The Scholarship of Teaching and Learning

Gullström, Cecilia January 2013 (has links)
Den här undersökningen inom fysikdidaktik utförs enligt ramverket The Scholarship of Teaching and Learning (SoTL). Det didaktiska verktyget som ska utvärderas benämns Pictionary Physics. Studien börjar med en litteraturöversikt av multipla representationer och interaktivt engagemang. Översikten syftar till att utforska hur lärandet kan möjliggöras vid användningen av det didaktiska verktyget. Pictionary Physics användes sedan för att främja en interaktiv användning av multipla representationer i en grupp bestående av fyra studenter. Studenternas agerande studerades och analyserades kvalitativt, följt av en utvärdering av studenternas upplevelser när de använde det didaktiska verktyget. Utvärderingen visar att Pictionary Physics kan gynna konceptuell förståelse för begrepp inom fysik. Utvärderingen visar även att det didaktiska verktyget skulle kunna bidra till förbättrat studieresultat då studenter uppmuntras att använda multipla representationer på ett interaktivt sätt. Fortsatt förädling av Pictionary Physics föreslås. Detta är stommen för SoTL, där tanken är att konsekvent utöka var kunskap om lärandet av fysik. / This physics education research project is carried out following the framework of the Scholarship of Teaching and Learning (SoTL). The didactic instrument investigated is termed Pictionary Physics. The study begins with a literature review of research on multiple representation, and interactive engagement. This review is used to evaluate the learning potential of the intended didactic instrument. Pictionary Physics was then used to facilitate the multi-representational interaction of a group of four physics students. The students’ behavior was studied and analyzed qualitatively, followed by an evaluation of the students’ experiences when using this didactic instrument. The investigation shows that Pictionary Physics may promote conceptual understanding of physics phenomena. The investigation also implies that this didactic instrument can contribute to improved learning outcomes when students are encouraged to interact by using multiple representations. Continued refinement of the Pictionary Physics concept is suggested. Such refinement is the essence of SoTL, incrementally expanding our knowledge of the teaching and learning of physics.
579

Risks Related to the Use of Software Tools when Developing Cyber-Physical Systems : A Critical Perspective on the Future of Developing Complex, Safety-Critical Systems

Asplund, Fredrik January 2014 (has links)
The increasing complexity and size of modern Cyber-Physical Systems (CPS) has led to a sharp decline in productivity among CPS designers. Requirements on safety aggravate this problem further, both by being difficult to ensure and due to their high importance to the public. Tools, or rather efforts to facilitate the automation of development processes, are a central ingredient in many of the proposed innovations to mitigate this problem. Even though the safety-related implications of introducing automation in development processes have not been extensively studied, it is known that automation has already had a large impact on operational systems. If tools are to play a part in mitigating the increase in safety-critical CPS complexity, then their actual impact on CPS development, and thereby the safety of the corresponding end products, must be sufficiently understood. An survey of relevant research fields, such as system safety, software engineering and tool integration, is provided to facilitate the discussion on safety-related implications of tool usage. Based on the identification of industrial safety standards as an important source of information and considering that the risks posed by separate tools have been given considerable attention in the transportation domain, several high-profile safety standards in this domain have been surveyed. According to the surveyed standards, automation should primarily be evaluated on its reliable execution of separate process steps independent of human operators. Automation that only supports the actions of operators during CPS development is viewed as relatively inconsequential. A conceptual model and a reference model have been created based on the surveyed research fields. The former defines the entities and relationships most relevant to safety-related risks associated with tool usage. The latter describes aspects of tool integration and how these relate to each other. By combining these models, a risk analysis could be performed and properties of tool chains which need to be ensured to mitigate risk identified. Ten such safety-related characteristics of tool chains are described. These safety-related characteristics provide a systematic way to narrow down what to look for with regard to tool usage and risk. The hypothesis that a large set of factors related to tool usage may introduce risk could thus be tested through an empirical study, which identified safety-related weaknesses in support environments tied both to high and low levels of automation. The conclusion is that a broader perspective, which includes more factors related to tool usage than those considered by the surveyed standards, will be needed. Three possible reasons to disregard such a broad perspective have been refuted, namely requirements on development processes enforced by the domain of CPS itself, certain characteristics of safety-critical CPS and the possibility to place trust in a proven, manual development process. After finding no strong reason to keep a narrow perspective on tool usage, arguments are put forward as to why the future evolution of support environments may actually increase the importance of such a broad perspective. Suggestions for how to update the mental models of the surveyed safety standards, and other standards like them, are put forward based on this identified need for a broader perspective. / Den ökande komplexiteten och storleken på Cyber-Fysiska System (CPS) har lett till att produktiviteten i utvecklingen av CPS har minskat kraftigt. Krav på att CPS ska vara säkra att använda förvärrar problemet ytterligare, då dessa ofta är svåra att säkerställa och samtidigt av stor vikt för samhället. Mjukvaruverktyg, eller egentligen alla insatser för att automatisera utvecklingen av CPS, är en central komponent i många innovationer menade att lösa detta problem. Även om forskningen endast delvis studerat säkerhetsrelaterade konsekvenser av att automatisera produktutveckling, så är det känt att automation har haft en kraftig (och subtil) inverkan på operationella system. Om verktyg ska lösa problemet med en ökande komplexitet hos säkerhetskritiska CPS, så måste verktygens påverkan på produktutveckling, och i förlängningen på det säkra användandet av slutprodukterna, vara känd. Den här boken ger en översikt av forskningsfronten gällande säkerhetsrelaterade konsekvenser av verktygsanvändning. Denna kommer från en litteraturstudie i områdena systemsäkerhet, mjukvaruutveckling och verktygsintegration. Industriella säkerhetsstandarder identifieras som en viktig informationskälla. Då riskerna med användandet av enskilda verktyg har undersökts i stor utsträckning hos producenter av produkter relaterade till transport, studeras flera välkända säkerhetsstandarder från denna domän. Enligt de utvalda standarderna bör automation primärt utvärderas utifrån dess förmåga att självständigt utföra enskilda processteg på ett robust sätt. Automation som stödjer operatörers egna handlingar ses som tämligen oviktig. En konceptuell modell och en referensmodell har utvecklats baserat på litteraturstudien. Den förstnämnda definierar vilka entiteter och relationer som är av vikt för säkerhetsrelaterade konsekvenser av verktygsanvändning. Den sistnämnda beskriver olika aspekter av verktygsintegration och hur dessa relaterar till varandra. Genom att kombinera modellerna och utföra en riskanalys har egenskaper hos verktygskedjor som måste säkerställas för att undvika risk identifierats. Tio sådana säkerhetsrelaterade egenskaper beskrivs. Dessa säkerhetsrelaterade egenskaper möjliggör ett systematiskt sätt att begränsa vad som måste beaktas under studier av risker relaterade till verktygsanvändning. Hypotesen att ett stort antal faktorer relaterade till verktygsanvändning innebär risk kunde därför testas i en empirisk studie. Denna studie identifierade säkerhetsrelaterade svagheter i utvecklingsmiljöer knutna både till höga och låga nivåer av automation. Slutsatsen är att ett brett perspektiv, som inkluderar fler faktorer än de som beaktas av de utvalda standarderna, kommer att behövas i framtiden. Tre möjliga orsaker till att ett bredare perspektiv ändå skulle vara irrelevant analyseras, nämligen egenskaper specifika för CPS-domänen, egenskaper hos säkerhetskritiska CPS och möjligheten att lita på en beprövad, manuell process. Slutsatsen blir att ett bredare perspektiv är motiverat, och att den framtida utvecklingen av utvecklingsmiljöer för CPS sannolikt kommer att öka denna betydelse. Baserat på detta breda perspektiv läggs förslag fram för hur de mentala modellerna som bärs fram av de utvalda säkerhetstandarderna (och andra standarder som dem) kan utvecklas. / <p>QC 20141001</p>
580

Management model to optimise the use of reverse osmosis brine to backwash ultra-filtration systems at Medupi power station / Frederik Jacobus Fourie

Fourie, Frederik Jacobus January 2014 (has links)
According to the Department of Water Affairs (DWAF, 2004 p.15), South Africa’s water resources are scarce and extremely limited and much of this precious resource is utilised and consumed in our industries. Treatment and re-use of effluent generated is, in some cases, preferred over use of alternate water resources (Du Plessis, 2008 p.3). The volume of effluent generated in treatment processes like ultra-filtration (UF) and reverse osmosis (RO) units is determined by the feed water quality, with high water loss through effluent generation at poor feed water quality. Current UF and RO applications require an increased UF production capacity due to the use of UF filtrate for periodic backwashing of the UF membrane units. This results in loss of water and decreases overall recovery. The need therefore exists to increase the overall recovery of product water from the raw water stream by reducing the amount of effluent generated. This would be possible to achieve by using RO brine to backwash the UF unit. The study was conducted to provide a modelling tool, assisting management to optimise the use of RO brine as backwash water on the UF system at the Medupi power station. The secondary objective of this study was the development of a modelling tool that can be used for other projects, new or existing, as a measure and indication of the usability of RO brine as backwash water on UF systems. By successfully applying this newly developed model, the viability of utilising the RO brine as backwash water for the UF was investigated. This modification would lead to utilizing smaller UF units than previously envisioned, which in turn leads to reducing capital cost with 11.07% and operating expenditure with 9.98% at the Medupi power station. This also has a positive environmental impact by reducing the amount of raw water used monthly by 10.34% (108 000 m3/month). / MIng (Development and Management Engineering), North-West University, Potchefstroom Campus, 2014

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