581 |
Risks Related to the Use of Software Tools when Developing Cyber-Physical Systems : A Critical Perspective on the Future of Developing Complex, Safety-Critical SystemsAsplund, 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>
|
582 |
Management model to optimise the use of reverse osmosis brine to backwash ultra-filtration systems at Medupi power station / Frederik Jacobus FourieFourie, 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
|
583 |
iPad som pedagogiskt och specialpedagogiskt verktyg i grundskolan : Lärares erfarenheter och beskrivningar - en intervjustudie / iPad as an educational and special educational tool in elementary school : A study of teachers´experiences and descriptionsWallin, Marie January 2014 (has links)
The purpose of this study is to examine how teachers in elementary school describe their work using iPad in education, as an educational and special educational tool to promote all students´ learning in school subjects. The study intends to answer the following research questions; how do the teachers describe their work with iPad as an educational tool? What kind of knowledge do the teachers describe the students get when working with iPad as an educational tool and how do the teachers describe the iPad as a tool from a special educational perspective. Qualitative research interviews have been used as a method to collect data for the study. The study is based on six interviews with teachers working in elementary school. The study´s theoretical base is the socio-cultural perspective on learning. The result shows that an iPad is used as an educational tool for both teachers and students. The teachers use the iPad at joint briefings in the classroom and as a tool for documentation and as a tool to reach the goals of the curriculum. The students use the iPad´s various applications to acquire knowledge in school subjects. It can apply to applications that benefit proficiency in mathematics or applications for basic reading and writing. Students also acquire knowledge by cooperating on an iPad. The students are described by their teachers as very knowledgeable when it comes to using iPad as a tool, sometimes the students know more than their teachers. The result also reveals some challenges with the iPad as a tool, for example, the iPad is not as easy to type on as a computer. From a special educational perspective, students that are in need of special education within language, communication and reading and writing can get help from using different applications to practice their difficulties. The conclusion of this study is that the use of iPad as an educational tool in elementary school creates great opportunities for learning, which applies for both students and teachers. An iPad is described as most useful when all students have their own and the iPad is made personal with applications to suit each individual student. Then it becomes easier to individualize and to encounter the student’s needs. / Syftet med studien är att undersöka hur lärare i grundskolan beskriver sitt arbete med att använda iPad i undervisningen, som pedagogiskt och specialpedagogiskt verktyg för att främja alla elevers lärande i skolans ämnen. Studien ämnar besvara följande frågeställningar; Hur beskriver lärarna arbetet med iPad som pedagogiskt verktyg? Vilka kunskaper beskriver lärarna att eleverna får med sig när man arbetar med iPad som pedagogiskt verktyg och hur beskriver lärarna en iPad som verktyg ur ett specialpedagogiskt perspektiv? Den kvalitativa forskningsintervjun har använts som metod för att samla in data till undersökningen. Studien bygger på sex intervjuer med lärare som arbetar i grundskolan. Studiens teoretiska utgångspunkt är det sociokulturella perspektivet på lärande. Resultatet visar att en iPad används som pedagogiskt verktyg för både lärare och elever. Lärarna använder iPaden vid gemensamma genomgångar i klassrummet och som ett verktyg för dokumentation och måluppfyllelse. Eleverna använder iPadens olika applikationer för att tillägna sig kunskap i skolans ämnen. Det kan gälla applikationer som gynnar färdighetsträning i matematik eller applikationer för grundläggande läs- och skrivinlärning. Eleverna tillägnar sig också kunskap genom att samarbeta kring en iPad. Eleverna beskrivs av sina lärare som mycket kunniga när det gäller att använda iPaden som verktyg och ibland kan eleverna mer än sina lärare. Resultatet visar också på vissa utmaningar med iPad som verktyg, till exempel att den inte är lika lätt att skriva på som en dator. Ur ett specialpedagogiskt perspektiv får elever i behov av särskilt stöd inom språk, kommunikation samt läs- och skrivinlärning hjälp av olika applikationer att träna sina svårigheter. Den slutsats jag kan dra av studien är att användandet av iPad som pedagogiskt verktyg i grundskolan skapar stora möjligheter för lärande, vilket gäller både för elever och lärare. En iPad beskrivs som mest användbar när alla elever har en egen och den görs personlig med applikationer som passar varje unik elev. På så sätt blir det lättare att individualisera och möta elevernas behov.
|
584 |
Leveransservice hos utvalda svenska e-handelsföretag : En studie om leveransservice som konkurrensmedel och kraven från konsumenternaAndersson, Sabina, Folkesson, Linn January 2014 (has links)
Bakgrund: Svenskarna ligger idag i topp på listan över andelen internetanvändare i befolkningen. Hela 94 procent av Sveriges befolkning använder internet och av dem har hela 84 procent någon gång handlat på internet. E-handeln växer så det knakar och det gör att konsumenternas krav på leveransservice ökar. Man kan se det som att leveransservice har utvecklats till ett nytt konkurrensmedel för att kunna överleva på en hårt konkurrensutsatt marknad. Syfte och forskningsfrågor: Syftet med studien är att undersöka och analysera svenska ehandelsföretags leveransservice för att bidra till en ökad förståelse för betydelsen av leveransservice. För att uppfylla syftet har följande forskningsfrågor utformats: Hur arbetar utvalda svenska e-handelsföretag med leveransservice som konkurrensmedel? Hur lever utvalda svenska e-handelsföretag upp till konsumenternas krav på leveransservice? Metod och tillvägagångssätt: Datainsamling har skett genom två metoder. Utvalda ehandelsföretag har intervjuats i syfte att ta reda på hur de arbetar med leveransservice. Detta har kombinerats med en enkätundersökning där konsumenters förväntan på leveransservice undersökts. Datan har tolkats och analyserats på ett kvalitativt sätt för att skapa en förståelse för ämnet. Slutsats: Studien visar att svenska e-handelsföretag lever upp till konsumenternas krav på leveransservice samt att de arbetar kontinuerligt för att fortsätta med detta. Resultatet av studien har bekräftat att leveransservice är ett viktigt konkurrensmedel men att det är svårt för e-handelsföretagen att hitta den optimala nivån att ligga på. I takt med att konsumenternas krav på leveransservice ökar gäller det för företagen att följa denna utveckling och ständigt arbeta med effektiviseringar.
|
585 |
Global Health Competency Skills: A Self-assessment for Medical StudentsAugustincic Polec, Lana 19 September 2012 (has links)
Global health is an emerging concern in a rapidly changing world in which health issues transcend international borders. This study developed and validated a new self-report questionnaire to assess self-perceived global health competencies among international medical students and how they are influenced by international clinical experiences. A tool consisted of two scales and four subscales with moderate internal consistency. Comparisons between participants who completed retrospective pretest (after the intervention retrospectively) and those who completed traditional pretest (before the intervention) revealed that those participants who completed the questionnaires retrospectively provided lower pretest scores, suggesting that response-shift bias had occurred. Significant increases in scores after international clinical experience were reported for the majority of global health competency measures in IFMSA group. Linear regression identified participant’s age, gross national income (GNI) of country of medical studies, GNI of the country visited, duration of international clinical experience and years of medical school completed, as significant predictors of global health scores. This study contributes valuable information about the newly developed global health competencies measurement tool.
|
586 |
Development of a design feature database to support design for additive manufacturing (DfAM)Maidin, Shajahan January 2011 (has links)
This research introduces a method to aid the design of products or parts to be made using Additive Manufacturing (AM), particularly the laser sintering (LS) system. The research began with a literature review that encompassed the subjects of design and AM and through this the need for an assistive design approach for AM was identified. Undertaking the literature review also confirmed that little has been done in the area of supporting the design of AM parts or products. Preliminary investigations were conducted to identify the design factors to consider for AM. Two preliminary investigations were conducted, the first investigation was conducted to identify the reasons for designing for AM, the need for a design support tool for AM and current challenges of student industrial designers designing parts or products for AM, and also to identify the type of design support they required. Further investigation were conducted to examine how AM products are developed by professional industrial designers and to understand their design processes and procedures. The study has identified specific AM enabled design features that the designers have been able to create within their case study products. Detailed observation of the case study products and parts reveals a number of features that are only economical or possible to produce with AM. A taxonomy of AM enabled design features was developed as a precursor for the development of a computer based design tool. The AM enabled design features was defined as a features that would be uneconomical or very expensive to be produced with conventional methods. The taxonomy has four top-level taxons based on four main reasons for using AM, namely user fit requirements, improved product functionality requirements, parts consolidation requirements and improvement of aesthetics or form requirements. Each of these requirements was expanded further into thirteen sub categories of applications that contained 106 examples of design features that are only possible to manufacture using AM technology. The collected and grouped design features were presented in a form of a database as a method to aid product design of parts or products for AM. A series of user trials were conducted that showed the database enabled industrial designers to visualise and gather design feature information that could be incorporated into their own design work. Finally, conclusions are drawn and suggestions for future work are listed. In summary, it can be concluded that this research project has been a success, having addressed all of the objectives that were identified at its outset. From the user trial results, it is clear to see that the proposed tool would be an effective tool to support product design for AM, particularly from an educational perspective. The tool was found to be beneficial to student designers to take advantage of the design freedom offered by AM in order to produce improved product design. As AM becomes more widely used, it is anticipated that new design features will emerge that could be included in future versions of the database so that it will remain a rich source of inspirational information for tomorrow s industrial designers.
|
587 |
Surfaces functionality of precision machined components : modelling, simulation, optimization and controlAris, Najmil Faiz Mohamed January 2008 (has links)
This research develops an analytical scientific approach for investigating the high precision surface generation and the quantitative analysis of the effects of direct factors in precision machining. The research focuses on 3D surface characterization with particular reference to the turning process and associated surface generation. The most important issue for this research is surface functionality which is becoming important in the current engineering industry. The surface functionality should match with the characterization parameters of the machined surface, which can be expressed in formula form as proposed in chapter 4. Modelling and simulation are extensively used in the research. The modelling approach integrates the cutting forces model, thermal mode% vibration model, tool wear model, machining system response model and surface topography model. All of those models are integrated as a whole model. The physical model with such as direct inputs is formed. The major inputs to the model are tooling geometry and the process variables. The outputs from the modelling approach are cutting force, surface texture parameters, dimensional errors, residual stress and material removal rate. MATLAB and Simulink are used as tools to implement the modelling and simulation. According to the simulation results, it is found that the feed rate has the most profound effect on in surface generation. The influence of the vibrations between the cutting tool and the workpiece on the surface roughness may be minimised by the small feed rate and large tool nose radius. Surface functionality simulation has been developed to model and simulate the surface generation in precision turning. The surface functionality simulation model covers the material and tool wear as well. It shows that chip formation is resulted from cutting forces. Cutting trials are conducted to validate the modelling and simulation developed. There are positive results that show the agreement between the simulation and experimental results. The analysis of the results of turning trials and simulations are conducted in order to find out the effects of process variables and tooling characteristics on surface texture and topography and machining instability. From the research, it can be concluded that the investigation on modelling and simulation of precision surfaces generation in precision turning is performed well against the research objectives as proposed. Recommendations for future work are to improve the model parameters identification, including comprehensive tool wear, chip formation and using Neural Networks modelling in the engineering surface construction system.
|
588 |
Social learning in mother-reared and "enculturated" capuchin monkeysFredman, Tamar January 2008 (has links)
This thesis explores social learning in mother-reared and “enculturated” capuchin monkeys (Cebus apella). At the outset a framework for understanding the social influence on learning is discussed, followed by a review of the social and cognitive abilities of capuchin monkeys, establishing the rationale for studying social learning in this species. Studies of wild capuchins suggest an important role for social learning but experiments with captive subjects have generally failed to support this. Some potential reasons for the lack of evidence in experimental settings are given. An example of using the two - method design to test social learning in acquiring behaviour by enculturated subjects is addressed. The results are related to findings with other species tested with a similar apparatus. Before testing mother-reared monkeys, an observational study of the object manipulation and tool-use repertoire of the subjects was carried out in order to facilitate the design of suitable social learning tasks for these monkeys. The first empirical study in Chapter 6 reports results of experiments with the enculturated and mother-reared capuchin monkeys employing the two -action method together with a third control group. The enculturated monkeys exhibited high fidelity copying that included the specific tool use technique witnessed while opening the foraging box. Mother-reared monkeys exhibited fidelity at a lower level, tending only to re-create the results the model had achieved. The second empirical study in Chapter 7 tested whether capuchin monkeys could show cumulative cultural learning manifested in the ability to switch from an established mode of manipulating a dipping box to a complex yet more advantageous one. Both populations were able to do so. The enculturated monkeys, as in the previous study, showed higher fidelity copying of the model. The last experiment was a preliminary study employing the “do as I do” method which was carried out with four of the enculturated monkeys. It provides suggestive evidence for at least one monkey's understanding of the task. The results of the studies are discussed in relation to previous experimental research as well as to data from capuchin monkeys in nature. The possible role of enculturation in social learning ability is considered.
|
589 |
"Fortsatt egenvård" prehospitalt : En patientsäker vårdnivå? / Prehospital "contiued self-care" : A safe level of care for patients?Lederman, Jakob January 2013 (has links)
No description available.
|
590 |
Bioinformatique et épissage dans les pathologies humaines / Bioinformatics and splicing in human diseasesDesmet, François-Olivier 07 December 2010 (has links)
Découvert en 1977, l'épissage est une étape de maturation post-transcriptionnelle consistant à rabouter les exons et éliminer les introns d'un ARN pré-messager. Pour que l'épissage soit correctement pris en charge par l'épisome et ses protéines auxiliaires, différents signaux sont présents le long de la séquence de l'ARN pré-messager. Il est maintenant reconnu que près de la moitié des mutations pathogènes chez l'homme impactent l'épissage, aboutissant à un dysfonctionnement du gène. Il est ainsi indispensable pour les biologistes d'être capables de détecter ces signaux sur une séquence génomique.Cette thèse a donc pour but de concevoir de nouveaux algorithmes permettant d'apporter la puissance de calcul des ordinateurs au service de la biologie de l'épissage. La solution proposée, Human Splicing Finder (HSF), est capable de prédire les trois types de signaux d'épissage à partir d'une séquence quelconque extraite du génome humain. Nous avons évalué l'efficacité de prédiction d'HSF dans l'ensemble des situations associées à des mutations pathogènes pour lesquelles il a été démontré expérimentalement leur impact sur l'épissage et par rapport aux autres algorithmes de prédiction. Parallèlement à ces apports directs tant pour la connaissance des processus biologiques de l'épissage que pour le diagnostic, les nouvelles approches thérapeutiques génotype-spécifiques peuvent également bénéficier de ces nouveaux algorithmes. Ainsi HSF permet de mieux cibler les oligonucléotides anti-sens utilisés pour induire le saut d'exon dans la myopathie de Duchenne et les dysferlinopathies.La reconnaissance récente de l'intérêt majeur de l'épissage dans des domaines aussi variés que la recherche fondamentale, la thérapeutique et le diagnostic nécessitaient un point central d'accès aux signaux d'épissage. HSF a pour objet de remplir ce rôle, en étant régulièrement mis à jour pour intégrer de nouvelles connaissances, et est d'ores et déjà reconnu comme un outil de référence. / Discovered in 1977, splicing is a post-transcriptional maturation process that consists in link-ing exons together and removing introns from a pre-messanger RNA. For splicing to be cor-rectly undertaken by the spliceosome and its auxiliary proteins, several signals are located along the pre-messanger RNA sequence. Nearly half of pathogenous mutations in humans are now recognized to impact splicing and leading to a gene dysfunction. Therefore it is es-sential for biologists to detect those signals in any genomic sequence.Thus, the goals of this thesis were to conceive new algorithms: i) to identify splicing signals; ii) to predict the impact of mutations on these signals and iii) to give access to this information to researchers thanks to the power of bioinformatics. The proposed solution, Human Splicing Finder (HSF), is a web application able to predict all types of splicing signals hidden in any sequence extracted from the human genome. We demonstrated the prediction's efficiency of HSF for all situations associated with pathogenous mutations for which an impact on splicing has been experimentally demonstrated. Along with these direct benefits for the knowledge of biological processes for splicing and diagnosis, new genotype-specific therapeutic approaches can also benefit from these new algorithms. Thus, HSF allows to better target antisense olignucleotides used to induce exon skipping in Duchenne myopathy and dysferlinopathies.The recent recognition of the major interest of splicing in various domains such as fundamen-tal research, therapeutics and diagnosis needed a one stop shop for splicing signals. HSF has for object to fulfill this need, being regularly updated to integrate new knowledge and is already recognized as an international reference tool.
|
Page generated in 0.0447 seconds