• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 85
  • 33
  • 22
  • 19
  • 17
  • 14
  • 6
  • 5
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 282
  • 33
  • 28
  • 27
  • 24
  • 23
  • 20
  • 19
  • 17
  • 15
  • 14
  • 14
  • 14
  • 13
  • 13
  • 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.
161

Towards stress-less UX design: How job search systems contribute to job search stress?

Come, Amarildo, Javaid, Muhammad January 2022 (has links)
Unemployment has long been considered a risk factor for mental health. While jobsearch is an extremely draining and stressful process, the job-search systems thatjobseekers use do not have to be. Among the many pressuring factors that are known tocontribute to stress, it remains unexplored how job search systems UX impactsjobseekers. This study aimed at identifying and understanding job search systemsrelated stressors based on existing stressor characteristics and on stressless designheuristics. To achieve this goal, semi-structured interviews were conducted incombination with a survey. Thematic analysis was performed to identify themes; and asurvey was conducted to gather the broader sentiment on job search experience.The results show that existing stressless design heuristics are effective in thinkingdesign for stress; as new themes emerged, three new heuristics are proposed.The 3 main stressors identified are related to poor UX in terms of feedback systems,complex interactions to fill in application forms, poor job description quality combinedwith a wanting job search capability. The major reasoning for the identified stressors isthat they are perceived as hindrances towards the main goal – getting a job.Stressor’s impact appears in the form of lowering job search engagement and makingjobseekers develop a negative attitude towards online job search.One important finding is that these stressors only become visible over time; this mighthave an implication on how software is tested and evaluated for stress. The findingswere discussed in view of previous studies, practical and scientific implications arepresented as well as suggestions for future research.
162

The problem of connectivity: A sociological study of the problem of connectedness of nationally produced science and national needs in Saudi Arabia

Assuliman, Abdusslam Wail Y. 30 May 2007 (has links)
This study is to investigate the problem of connectivity between nationally produced science and national needs. It is a collective case study of two academic departments within Saudi academia, the departments of petroleum engineering at Alpha and Beta Universities. The rationale for using these departments is that Saudi Arabia has an advanced petroleum industry, making petroleum engineering a good case for investigating the connectivity of nationally produced science with national needs. The main tool of the study was in-depth tape-recorded interviews. Twenty-two interviews were conducted, sixteen with current and retired faculty members at the petroleum engineering departments of Alpha and Beta and six with administrators at both universities. In addition, documents and observation were used as tools. The two departments differ in their levels of connectivity with national industry. One is increasingly connected with national industry, while the other is completely isolated from national industry. Historical and regulatory factors play a role in this difference. Four themes were generated from the data: institutional arrangements, positive attitude and self confidence, social construction of the university, and rentier mentality. The data gathered show that the issue of connectivity is beyond the will and abilities of individual scientists; it is a result of organizational efforts of the scientific institutions reinforced by the willingness of the productive sectors to change their behavior toward national scientists. / Ph. D.
163

NEGATIVE DIELECTRIC CONSTANT OF PHOTO-CONDUCTING POLYMERS UPON CORONA-CHARGING

Yan, Han 04 1900 (has links)
<p>The phenomenon of image blurring on laser-printed or electro-photocopied paper has been discovered since the 1980s. In the 1990s, the problem was confirmed to be associated with the undesired surface conduction along the unique photoconductive polymer surface during the photoconduction process. Other than this, little progress has been made in investigating this phenomenon, due to the limited experimental techniques.</p> <p>In this thesis, the electrical properties of a commercially available photoconductor as a result of Corona charging were studied. Various techniques including vacuum deposition and step-function impedance spectroscopy were employed, to overcome the nature of the photoconductor that prevented the use of conventional techniques such as AC impedance spectroscopy. Negative dielectric constant (NDC) has been prevalently discovered at a broad range of frequencies (below 1Hz and up to 1 MHz) and it was questioned in the form of a physically-impossible inductor. This precipitous sign switch of dielectric constant is found in various areas ranging from physics, chemistry, biology to electronics. The magnitude of the NDC decreased drastically with the decrease of electric field frequency. The system obeyed the proposed free-carrier plasma model with a resonance frequency at MHz level.</p> <p>Commercially available polymeric photoconducting materials showing NDC at extremely low frequency are expected to provide unusual scattering to electromagnetic waves and therefore demonstrate profound implications with reduced cost. It has paved the way for many applications such as inductors in integrated chips without bulky coils and provides an insight into a possible revolution in electronics and photonics.</p> / Doctor of Philosophy (PhD)
164

Charge transport study of InGaAs two-color QWIPs

Hoang, Vu Dinh 06 1900 (has links)
Approved for public release, distribution is unlimited / In this thesis, a series of experiments were performed to characterize the material properties of InGaAs/GaAs for use in a two-color quantum-well IR photodetector (QWIP) design. Results from room temperature studies using cathodoluminescence and photoluminescence indicated light emission at 858 nm and 1019 nm from GaAs and InGaAs, respectively. Using a direct transport imaging technique, an edge dislocation pattern was observed and shown to be confined to the InGaAs layer of the material. A dislocation density measurement was performed and was shown to be less than 2000 lines/cm. Quantitative intensity level measurements indicated fluctuation in the region of dislocations to be less than 30% of the signal to background level. Finally, a spot mode study using the direct transport imaging method was performed to evaluate the feasibility of using this technique for contact-less diffusion length measurements. / Civilian, Department of Air Force
165

Military Spending, External Dependence, and Economic Growth in Seven Asian Nations: a Cross-National Time-Series Analysis

Ko, Sung-youn 05 1900 (has links)
The theme of this study is that seven major East Asian less developed countries (LDCs) have experienced "dependent development," and that some internal and external intervening factors mattered in that process. Utilizing a framework of "dependent development," the data analysis deals with the political economy of development in these countries. This analysis supports the fundamental arguments of the dependent development perspective, which emphasize positive effects of foreign capital dependence in domestic capital formation and industrialization in East Asian LDCs. This perspective assumes the active role of the state, and it is found here to be crucial in capital accumulation and in economic growth. This cross-national time-series analysis also shows that the effects of external dependence and military spending on capital accumulation and economic growth can be considered as a regional phenomenon. The dependent development perspective offers a useful way to understand economic dynamism of East Asian LDCs for the past two decades.
166

Does Transdermal Nicotine-Induced Withdrawal Suppression Depend on Smokers' Gender?

Evans, Sarah Ellen 01 January 2005 (has links)
Nicotine replacement therapy (NRT) is a pharmacotherapy used commonly to help tobacco smokers quit smoking. All forms of NRT are demonstrably efficacious for this indication, and several forms, including transdermal nicotine (TN) are available over-the-counter in the United States. NRT is less efficacious in women than in men, although the specific reasons for this gender difference are unknown. NRT generally, and TN specifically, is thought to work, at least in part, by suppressing withdrawal symptoms in abstinent smokers. While TN-induced withdrawal suppression has been demonstrated, the degree to which this withdrawal suppression is influenced by smokers' gender is uncertain. The purpose of this acute laboratory study is to determine if TN-induced withdrawal suppression is influenced by smokers' gender.One hundred twenty eight overnight-abstinent smokers completed four, double-blind, randomized, 6.5-hour laboratory sessions in which further cigarette abstinence was required. Sessions differed by TN dose (0, 7, 21, or 42 mg). All sessions were double-blind and randomly ordered. Each session included regular assessment of subjective symptoms of nicotine/tobacco withdrawal, subjective effects of transdermal nicotine dose, psychomotor performance, heart rate and plasma nicotine level. Results from this laboratory study revealed clear nicotine dose-related effects for plasma nicotine and heart rate, symptoms of nicotine intoxication (e.g. Nausea, Lightheaded) and suppression of Urges to smoke and Craving. Many DSM IV nicotine/tobacco withdrawal symptoms did not show dose-related suppression (e.g. Irritability/frustration/anger, Anxious, Difficulty concentrating). Importantly, results from this study indicated that there were very few differences between men and women in nicotine-induced suppression of the nicotine/tobacco withdrawal syndrome. Future research addressing this important issue may benefit from focusing on a potential interaction between gender and other effects of TN (i.e., blunting the effects of a concurrently administered cigarette) and/or on other triggers for relapse (i.e., smoking-related stimuli).
167

Effet de l'environnement sur la croissance et l'accumulation de métabolites secondaires chez Datura innoxia Mill. cultivé en conditions hors sol ; impact des facteurs biotiques et abiotiques / Effects of biotic and abiotic environmental parameters for Datura innoxia Mill. tropane alkaloid in soilless cultures

Vu, Thi Dao 04 July 2008 (has links)
Datura innoxia Mill., une plante de la famille des Solanacées synthétisant des métabolites secondaires, dont les alcaloïdes tropaniques, a été utilisée comme modèle pour cette étude portant sur les cultures en hydroponie. Nous avons déterminé et hiérarchisé les paramètres environnementaux (biotiques et abiotiques) permettant d’améliorer croissance et production de métabolites. La réponse de la plante dépend de l’approvisionnement en oxygène de la solution nutritive, de la température perçue tant niveau des parties aériennes qu’au niveau racinaire. Une augmentation de l’intensité d’éclairage n’améliore pas la teneur en alcaloïdes de la plante mais l’utilisation de lumière orange engendre un changement des paramètres de croissance et des teneurs en molécules recherchées. Nous avons également montré que la présence de microflore dans le milieu de culture provoque une dégradation des molécules d’intérêt et altère leur accumulation dans la plante. Par contre, A. rhizogenes a un effet favorable sur la croissance de la biomasse et la biosynthèse d’alcaloïdes tropaniques dans la plante. L’état transgénique des racines, issues de co-culture hydroponique de Datura innoxia avec A. rhizogenes TR7, a été estimé par une vérification précoce et confirmé par des analyses moléculaires. Nous avons pu mettre en évidence les modifications du phénotype racinaire et les mécanismes d'interaction plante-microorganisme. L’inoculation des agrobactéries peut donner lieu à des transferts naturels de gènes induisant ainsi l’obtention d’un pool racinaire chimérique regroupant des racines normales et des racines transformées. Ces travaux ont ouvert de nouvelles perspectives en vue de déterminer la capacité de production de métabolites secondaires par des plantes en culture hors sol, de manière à obtenir une biomasse riche en molécules recherchées / Datura innoxia Mill. a plant species belonging to Solanaceous family, produces hyoscyamine and scopolamine as two main tropane alkaloids. It has been studied in the present work for the development of hydroponic based secondary metabolites bioproduction. More specifically, biotic and abiotic environmental factors have been analysed in order to improve growth and alkaloid accumulation in plant tissues. Oxygen concentration in the nutrient solution is proved to be important for both biomass and compound production in temporary immersion culture conditions occur as one optimum. Temperature has also a major effect, directly and most probably through oxygen solubility and root needs. We showed that artificial light may positively complete natural one but the kind of spectrum must be chosen carefully. From this point of view, orange light from High Pressure Natrium Vapour light showed better results than classical white light. Nitrogen (NO3-15mM) and pH (5 to 6) management may lead to culture optimization. We also show that well chosen wild Agrobacterium rhizogenes strains may be added to the hydroponic nutrient solution in order to improve growth and alkaloid bioproduction. This result is due to the multi occurrence of genetic transformation events. Our results lead to a first classification for impacts of biotic and abiotic factors. It opens new window for plant milking technology industrial development
168

Vilken komplexitet upplever revisorn vid revidering av mindre komplicerade företag i Sverige? : ur ett International Standards of Auditing (ISA) perspektiv.

Lomryd, Amanda, Kronvall, Nora January 2019 (has links)
Previous research has focused on finding reasons to why smaller companies (SMEs) choose voluntary audit. The IAASB has in 2018 suggested a move away from the SME concept and has instead talked about audit of less complex entities. A problematization of using ISA for such entities is the bases for the new IAASB project. An explorative analysis of complexity in the audit of these entities, using ISA, is currently lacking in academic literature.   The study therefore aims to identify the complexity that auditors perceive in the audit of less complex entities in Sweden, using ISA. However, complexity within the auditing industry is still very diffuse and unidentified. Though many of the smaller companies choose to be audited, regulations like ISA are too large for this type of company. We are using interviews to achieve the aim of the study and the legitimacy theory and stakeholder theory to explain complexity. In order to identify where in the process the complexity is perceived, we are basing the research on the audit process.   The result of the study shows that it is challenging to define complexity when conducting an ISA based audit on less complex entities. Although, the results show that complexity exists, or at times, ‘ill-fit’, with ISA for these entities. Thus this thesis finds that there is an increasing demand amongst auditors for a new standard for these entities. The study attempts to contribute with an explanation of complexity, and our expectations are that future research will continue exploring this area. / Tidigare forskning har fokuserat på att finna anledningen till varför de mindre företagen väljer att bli reviderade, men vi har inte uppfattat att fokus har lagts på specifikt de mindre komplicerade företagen. Inte heller har det fokuserats på den komplexitet som upplevs och uppstår vid revidering av denna typ av företag, utifrån regelverket ISA.   Studiens syfte är att identifiera den komplexitet revisorer upplever vid revidering av mindre komplicerade företag i Sverige, utifrån ett ISA-perspektiv. Vårt ämnesområde är relativt outforskat och det inte är förrän nyligen som begreppet mindre komplicerade företag blivit aktuellt. Dock är begreppet komplexitet inom revisionsbranschen fortfarande diffust och odefinierat. Ämnesområdet är ett aktuellt ämne eftersom många mindre företag väljer att bli reviderade trots att krav ej föreligger, men med ett regelverk som ISA upplevs det som ingående och omfattande för denna typ av företag. Vi använder oss av intervjuer för att uppnå studiens syfte, och utgår från legitimitetsteorin och intressentmodellen för att försöka förklara komplexiteten. Vi utgår från revisionsprocessen för att identifiera var i processen som den upplevda komplexiteten existerar.   Studiens resultat visar på att revisorerna upplever en komplexitet, men att den är svårdefinierad. Det finns även en ökad efterfrågan bland revisorerna på en ny separat standard för de mindre komplicerade företagen. Studiens bidrag är att bidra med en förklaring av begreppet komplexitet utifrån det revisorerna uttryckt, och våra förhoppningar är att framtida forskning ytterligare ska beröra detta outforskade område.
169

Configuração de uma rede de distribuição capacitada com restrição de cobertura. / Configuring a capacitated distribution network with coverage constraint.

Pires, Thiago 05 May 2006 (has links)
O presente estudo trata da configuração de uma rede de distribuição capacitada com restrição de cobertura. O objetivo é determinar quais cidades, dentre um conjunto de candidatas, devem atuar como centrais de desconsolidação de carga, de forma a minimizar o custo total de transporte (transferência e distribuição) para uma determinada demanda, atendendo às restrições operacionais e de distância de cobertura. A partir da pesquisa na literatura sobre o assunto, foi preparado um modelo de programação linear inteira para encontrar a solução ótima para o problema. Esse modelo é baseado nos clássicos problemas de localização, com modificação na função objetivo para retratar melhor a estrutura de custos de transporte, além da inclusão de restrições de cobertura e restrições de atendimento mínimas e máximas em cada central. O modelo foi implementado utilizando o suplemento Solver da planilha eletrônica Excel. Um outro enfoque de solução baseado na metaheurística Busca Tabu (Tabu Search) foi elaborado, com dois objetivos: permitir a análise de problemas quando não se tem disponível uma ferramenta para solução de modelos de programação linear; e analisar o comportamento da metaheurística quando utilizada na solução desse tipo de problema. O procedimento foi implementado a partir da construção de macros em linguagem Visual Basic for Application (VBA), também em Excel. O modelo de programação linear e a metaheurística Busca Tabu foram aplicados a alguns cenários de um problema real. Resultados, comparações e conclusões dessas aplicações são apresentados neste trabalho. / The present study deals with configuring a capacitated distribution network with coverage constraint. The objective consists of determining which cities, among a set of candidates, should act as load deconsolidation centers, aiming to minimize transportation total costs to attend a given demand, and obeying all operational constraints and coverage distances. Based on a literature review, an integer linear programming model was formulated to find the problem optimal solution. The model is based on classical location problems, but includes changes in the objective function to incorporate the transportation costs structure, besides coverage constraints and minimum and maximum central capacity constraints. The model was implemented using Excel’s Solver add-in. Another solution approach based on the Tabu Search metaheuristic was proposed, with two objectives: to permit problem analysis when linear programming tools are not available; and to learn on metaheuristic behavior when used to solve this type of problem. The Tabu Search procedure was implemented using Excel macro language in Visual Basic for Applications (VBA). Both integer linear programming and metaheuristic models were applied to some scenarios of a real-world problem. Applications results, comparisons and conclusions are presented in this work.
170

Enhanced impact resistance and pseudo plastic behaviour in composite structures through 3D twisted helical arrangement of fibres and design of a novel chipless sensor for damage detection

Iervolino, Onorio January 2017 (has links)
The future of the aerospace industry in large part relies on two factors: (i) development of advanced damage tolerant materials and (ii) development of advanced smart sensors with the ability to detect and evaluate defects at very early stages of component service life. Laminated composite materials, such as carbon fibre reinforced plastics (CFRP), have emerged as the materials of choice for increasing the performance and reducing the cost and weight of aircrafts, which leads to less fuel consumption and therefore lower CO2 emissions. However, it is well known that these materials exhibit fragile behaviour, poor resistance to impact damage caused by foreign objects and require a relatively slow and labour intensive manufacturing process. These factors prevent the rapid expansion of composite materials in several industrial sectors at the current time. Inspired by the use of rope throughout history and driven by the necessity of creating a lean manufacturing process for composites and enhancing their impact properties, the first part of this work has shown that enhanced damage tolerance and pseudo-ductile behaviour can be achieved with standard CFRP by creatively arranging the fibres into a 3D twisted helical configuration. Through an extensive experimental campaign a new method to arrange fibre reinforcement was presented and its effect investigated. The second part of this PhD work focused on developing a new smart sensor. A spiral passive electromagnetic sensor (SPES) for damage detection on CFRP and glass fibre reinforced plastics (GFRP) is presented in this work. A range of defect types in glass and carbon composite has been considered, such as delamination, perforated holes and cracks. Furthermore, throughout this work, the SPES has been exploited as a multi-sensing device allowing the ability to detect temperature and humidity variation, presence of ice and act as an anti/de-icing device.

Page generated in 0.0317 seconds