• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 141
  • 36
  • 33
  • 30
  • 22
  • 15
  • 14
  • 9
  • 9
  • 7
  • 7
  • 5
  • 4
  • 3
  • 2
  • Tagged with
  • 377
  • 185
  • 120
  • 111
  • 58
  • 50
  • 49
  • 46
  • 45
  • 45
  • 40
  • 38
  • 38
  • 37
  • 36
  • 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.
81

Integrated lifecycle requirements information management in construction

Jallow, Abdou Karim January 2011 (has links)
Effective management of information about client requirements in construction projects lifecycle can contribute to high construction productivity; within budget and schedule, and improve the quality of built facilities and service delivery. Traditionally, requirements management has been focused at the early stages of the construction lifecycle process where elicited client requirements information is used as the basis for design. Management of client requirements does not extend to the later phases. Client requirements often evolve and change dramatically over a facility's life. Changing client requirements is one of the principal factors that contribute to delays and budget overruns of construction projects. This results in claims, disputes and client dissatisfaction. The problems of current requirements management process also include: lack of integrated and collaborative working with requirements; lack of integrated requirements information flow between the various heterogeneous systems used in the lifecycle processes, and between the multiple stakeholders; inefficient and ineffective coordination of changes within the lifecycle processes; manual checking of dependencies between changing requirements to facilitate assessment of cost and time impact of changes. The aim of the research is to specify a better approach to requirements information management to help construction organisations reduce operational cost and time in product development and service delivery; whilst increasing performance and productivity, and realising high quality of built facilities. In order to achieve the aim and the formulated objectives, firstly, a detailed review of literature on related work was conducted. Secondly, the research designed, developed and conducted three case studies to investigate the state-of-the-art of managing client requirements information. A combination of multiple data collection methods was applied which included observations, interviews, focus group and questionnaires. Following this, the data was analysed and problems were identified; the necessity for a lifecycle approach to managing the requirements information emerged. (Continues...).
82

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

Kamal, Khurram January 2008 (has links)
The huge landfills from solid waste generated by the massive utilisation of different products from domestic sources are badly affecting the environment. About 70% of the solid municipal waste, two thirds of which comprises of household waste, is dumped as landflll all over the world. For efficient product lifecycle management via upgrade, maintenance, reuse, refurbishment, and reclamation of components etc., storage of product related information throughout its lifecycle is indispensable. Efficient use of information technology integrated with product design can enable products to manage themselves in a semiautomatic and intelligent manner. It means that products themselves should contain informationú that what to do with them when they are of no use. More advanced products may locate themselves and communicate with their recyclers through internet or some other communication technology. In this regard, different types of technologies have been investigated. These technologies are broadly classified as passive embedded information devices and active embedded information devices. Methods of automatic identification in combination with information technology can act as passive Embedded Information Devices (EID) to make products intelligent enough in order to manage associated information throughout their life cycles. Barcodes, Radio Frequency Identification tags, and a new technology called i-button technology were investigated as possible candidates for passive EIDs. The ibutton technology from the perspective of product lifecycle management is presented for the very first time in the literature. Experiments demonstrated that RFID and i-button technologies have potential to store not only the static but dynamic data up to some extent, such as small maintenance logs. As passive EIDs are unable to store the sensory data and detailed maintenance logs regarding a product, therefore, in addition to these demonstrators for passive EIDs, an advanced active EID demonstrator for lifecycle management of products with high functional complexity is also presented. Initially, the idea is presented as smart EID system that r~cords the sensory data of a refrigerator compressor and stores the detailed maintenance logs into the product itself. However, this idea is extended as intelligent EID that is implemented on a gearbox in order to predict the gearbox lifetime under an accelerated life test. This involves developmen,t of a novel on-chip life prediction algorithm to predict the gearbox lifetime under accelerated life testing scenario. The algorithm involves a combination of artificial neural networks and an appropriate reliability distribution. Results of accelerated life testing, simulation for the choice of appropriate reliability distribution and the life prediction algorithm are presented. Bi-directional communication software that is developed in order to retrieve lifecycle data from the intelligent EID and to keep intelligent EID updated is also explained. Overall, embedded information devices can be proposed as a good solution to support a sustainable approach to lifecycle management.
83

Modification and upgrade of AzRISE/TEP solar photovoltaic test yard

Bennett, Whit, Fishgold, Asher, Lai, Teh, Elwood, Teri, Potter, Barrett G., Simmons-Potter, Kelly 26 September 2016 (has links)
The University of Arizona AzRISE (Arizona Research Institute for Solar Energy) and Tucson Electric Power solar test yard is currently undergoing renovations to upgrade and standardize the data acquisition capabilities throughout the yard. Test yard improvements have enabled increased data collection reliability through state-of-the-art and environmentally-robust data logging and real-time analysis. Enhanced capabilities include 10 msec max. data resolution, precision PV backside temperature monitoring of both individual and strings of modules, measurement of both AC and DC outputs as well as GHI and POA irradiance, active data backup to eliminate data intermittency, and robust Ethernet connectivity for data collection. An on-site weather station, provides wind speed and direction, relative humidity, and air temperature data. The information collected is accessed remotely via web server and includes raw performance and environmental conditions as well as extracted figures of performance for systems under test. Complementing the UA's existing accelerated environmental-testing chamber, the new test yard acquisition capabilities have enabled high fidelity system and sub-system-level operational testing under a range of field-level test conditions. The combined facilities, thus, provide a full-spectrum testing resource for photovoltaic performance and degradation analysis. Specific measurement characteristics and sample data collected from a polysilicon module test string are utilized to illustrate test yard capabilities.
84

Mapping of development process for Tacit knowledge transfer in Product development organization : Knowledge management in change managent / Mapping of development process for Tacit knowledge transfer in Product development organization : Knowledge management in change managent

Ganesh, Koushik, Pravin Kumar, Prithivraj January 2017 (has links)
The thesis is focused on developing a set of work standards or framework to the company, Isaberg Rapid which has changed its parent company and because of it lost many of its experienced employees. Subsequently a lot of implicit knowledge is lost along with the employees, which later became evident when challenges recurred in production. The aim of the research project is to create a proof methodology to avoid this loss by storing this tacit knowledge for any references, even if the employees involved with the product are lost.
85

Utilizing Economic and Environmental Data from the Desalination Industry as a Progressive Approach to Ocean Thermal Energy Conversion (OTEC) Commercialization

Eller, Michael R 20 December 2013 (has links)
Ocean Thermal Energy Conversion (OTEC) is a renewable energy technology that has to overcome several key challenges before achieving its ultimate goal of producing baseload power on a commercial scale. The economic challenge of deploying an OTEC plant remains the biggest barrier to implementation. Although small OTEC demonstration plants and recent advances in subsystem technologies have proven OTEC’s technical merits, the process still lacks the crucial operational data required to justify investments in large commercial OTEC plants on the order of 50-100 megawatts of net electrical power (MWe-net). A pre-commercial pilot plant on the order of 5-10 MWe-net is required for an OTEC market to evolve. In addition to the economic challenge,OTEC plants have potential for adverse environmental impacts from redistribution of nutrients and residual chemicals in the discharge plume. Although long-term operational records are not available for commercial sizeOTEC plants, synergistic operational data can be leveraged from the desalination industry to improve the potential for OTEC commercialization. Large capacity desalination plants primarily use membranes or thermal evaporator tubes to transform enormous amounts of seawater into freshwater. Thermal desalination plants in particular possess many of the same technical, economic, and environmental traits as a commercial scale OTEC plant. Substantial long-term economic data and environmental impact results are now widely available since commercial desalination began in the 1950s. Analysis of this data indicates that the evolution of the desalination industry could be akin to the potential future advancement of OTEC. Furthermore, certain scenarios exist where a combined OTEC-desalination plant provides a new opportunity for commercial plants. This paper seeks to utilize operational data from the desalination industry as a progressive approach towards OTEC commercialization.
86

A Multivariable Statistical Approach to Managing United States Coast Guard Small Boats

Fitzpatrick, Brian D 16 May 2014 (has links)
The Coast Guard has developed several systems to measure the performance of its engineering and logistics organizations. The development of these measures is based upon the need to show where and how the organization meets the American taxpayer’s needs. The use of multivariable regressions and determining the statistical distributions of the variables will show the adequacy of the measures and processes currently used. They will also determine a better way to measure the performance of the Coast Guard Small Boat Fleet. This research will analyze the 47 Motor Life Boat and 25 Response Boat-Small data from fiscal year 2011 to 2013. The focus will be on improving the measure used by the engineering and systems managers of the Coast Guard to manage assets and resources, as well as making recommendations on how to improve the processes involved in managing a robust engineering and logistics system.
87

Gestão do ciclo de vida de produtos: seleção de sistemas PLM com base em modelos de referência / Product lifecycle management: PLM systems selection based on reference models

Zancul, Eduardo de Senzi 16 March 2009 (has links)
A gestão do ciclo de vida de produtos (Product Lifecycle Management) é uma abordagem para a gestão integrada dos processos de negócio e das informações relacionadas aos produtos. Tal abordagem requer a utilização de sistemas de informação (Sistemas PLM) para apoiar a colaboração na empresa estendida, ao longo de todo o ciclo de vida. O problema prático que motiva a realização deste trabalho é a dificuldade enfrentada pelas empresas, atualmente, em avaliar os sistemas PLM existentes no mercado e em selecionar a alternativa mais adequada aos seus processos de negócio. A análise da situação atual da pesquisa na área indica que faltam métodos e instrumentos para apoiar a seleção de sistemas PLM. Visando preencher essa lacuna e propor uma solução para o problema identificado, o trabalho tem como objetivos definir um modelo de referência de sistemas PLM, que represente de forma genérica as funcionalidades que caracterizam esse tipo de sistema, e desenvolver um método para a seleção de sistemas PLM baseado em modelos de referência. A fim de atingir esses objetivos, são gerados quatro resultados principais. O primeiro resultado do trabalho é o framework conceitual de elementos do PLM, que organiza o conhecimento existente sobre PLM de forma estruturada, para que ele possa servir de referência em projetos de implantação da gestão do ciclo de vida de produtos em empresas. O segundo resultado é o modelo de referência de sistemas PLM, que permite estabelecer uma base comum para a comparação entre os diversos sistemas PLM disponíveis comercialmente. O terceiro resultado é o modelo integrado processo-sistemas PLM e a ferramenta para utilização desse modelo integrado na prática. Por fim, o quarto resultado é o método de seleção de sistemas PLM com base em modelos de referência, que utiliza o modelo integrado processo-sistemas PLM para orientar a seleção do sistema mais adequado a uma empresa específica. A avaliação dos resultados indica que os instrumentos e o método propostos neste trabalho contribuem para auxiliar as empresas, especialmente as empresas de médio porte, na identificação de um sistema PLM adequado para atender aos requisitos de seus processos de negócio. / Product Lifecycle Management is an approach to the integrated management of business processes and product-related information. This approach requires information systems (PLM Systems) to provide collaboration support throughout the business and across product lifecycle. The practical problem that gave rise to this research was the challenge companies currently face in assessing existing PLM systems and in selecting the best alternative for their business processes. Examining the status of the research carried out in the field to date shows that there is a lack of methods and tools to effectively support companies in choosing their PLM Systems. Aiming at closing this gap and offering a solution for this problem, the goals of this study are: to provide a definition for PLM system reference models that generally represents the functionalities that characterize this kind of system, and to develop a method for choosing PLM systems based on the reference models. In meeting these goals, this research arrived at four main results. Firstly, at a conceptual framework of PLM elements providing an organized structure of the existing knowledge developed so far on PLM. This framework can be used as a reference in projects to implement product lifecycle management in companies. Secondly, at a PLM system reference model that establishes a common basis for comparing the many PLM systems available in the market. Thirdly, at an integrated PLM process-system model and tool for using this integrated model in practice. Lastly, at a method for selecting PLM systems based on the reference model, that uses the integrated PLM process-system model to support and guide users in choosing the best system for a certain company. The assessment of the results shows that the proposed tools and method effectively help companies, specially medium-sized businesses, in identifying the most adequate PLM system to meet their business process requirements.
88

An investigation into the factors affecting the behaviour of Highway Filter Drains, with a particular emphasis on the Scottish Trunk Road Network

Mitchell, Ged January 2017 (has links)
Approximately 1500 km (43%) of the strategic Scottish trunk road network drainage asset takes the form of Highway Filter Drains (HFDs). However, despite their popularity, they are prone to clogging, therefore they have an estimated operational life-cycle of ten-years. This research was undertaken to investigate the complex inter-relationship between catchment characteristics, road dynamics and the physical characteristics of the road to establish the key factors that govern the generation and spatial variability of Road-Deposited-Sediment (RDS). The aim being to establish the impact RDS Particle Size Distribution (PSD) has on clogging and the operational life-cycle of HFDs. The research adopted an integrated approach, incorporating: (i) a Field Study to investigate RDS PSD grading envelopes across the Scottish trunk road network, (ii) a HFD Field Survey (HFD-FS) to investigate the current condition of HFDs across a range of catchments, (iii) a HFD Field Study to establish whether, or not, graded stone PSD envelopes comply with specification requirements when first placed in the trench, (iv) 3 HFD Field Studies to assess the level of risk of system failure through evaluating the causes and quantifying the individual, cumulative and influencing factors which contribute to the evolution of clogging in HFDs, and (v) a Field Study utilising Ground Penetrating Radar data to explore why stratified (clogged) layers evolve within some HFDs. Based on the results of this research, design and maintenance procedures were then identified to improve the performance of HFDs. Results established that Scottish trunk roads operate under variable catchment characteristics and road dynamics, with the condition and specification of the road surface, volume of traffic, road geometry, number of running lanes and adjacent land use governing the generation and spatial variability of RDS. Five of the nine trunk road RDS PSD profiles shared a peak particle diameter of 425 μm, two had a peak of 600 μm, one had a peak of 1180 μm and one resulted in a peak of 2120 μm. Particles >1000 μm were mostly mineral or asphalt and it was shown that there is a direct link between the factors that govern the generation and spatial variability of RDS and those that govern the evolution of clogging and actual operational life-cycle of HFDs. The HFD-FS revealed that 69% were assigned Filter Drain Condition Index ratings of 3 or below, which identifies these as having exceeded the ten-year estimated operational life-cycle. 94% of those deemed to have reached the end of their operational life-cycle were over-the-edge (OTE) HFDs, which supports the assertion that pre-treatment would increase their operational life-cycle. Results also established that introducing a kerb-line and gully-pots or grass-strip between the road and the HFD significantly reduced the indices of particle size composition d50 and d90 and percentage of RDS retained at depths spanning 0 - 400 mm, compared to OTE HFDs with comparable catchment characteristics and road dynamics. Based on these results, the operational life-cycle of HFDs with a kerb-line and gully-pots and OTE HFDs with a grass-strip can be expected to exceed twenty-years, if catchment characteristics and road dynamics are representative of those in this study. This research also identified that compacting Type B graded stone with ‘heavy vibrating machinery’ during construction could potentially contribute to clogging. It was also established that HFD harrowing may exacerbate clogging because the process of disintegrating the cake-layer mobilises an otherwise rigid and compacted RDS mass and this is more likely to penetrate deeper into the HFD and inundate the HFD during a storm event. These findings indicate that current HFD construction and maintenance practice could have a detrimental impact on the effective operational life-cycle of HFDs. Overall, this research study has demonstrated that there are considerable uncertainties related to PSD grading envelopes and percentage of RDS migrating from roads to HFDs. It is clear therefore that one of the most notable findings of this research is that given the scale of strategic trunk road networks, assuming a single HFD operational life-cycle profile, for a trunk road or trunk road network, is highly unlikely to be representative of a HFD at the local level. It follows then that the widely accepted estimated ten-year operational life-cycle for HFDs, does not reflect the actual operational life-cycle of HFDs.
89

Nouveaux éléments dans la compréhension des mécanismes d'entrée du virus de l'hépatite C / New insights in the understanding of hepatitis C virus entry mechanisms

Fénéant, Lucie 20 March 2015 (has links)
Le Virus de l’Hépatite C (HCV) est un problème majeur de santé publique qui touche plus de 170 millions de personnes dans le monde. Le HCV cible essentiellement les hépatocytes où il effectue son cycle de réplication qui peut-être divisé en trois étapes majeures : l’entrée de la particule virale qui aboutit à la libération de l’ARN viral dans le cytoplasme, la traduction/réplication du génome viral et l’assemblage/sécrétion des particules néosynthétisées. Durant ma thèse, nous nous sommes intéressés à l’étape d’entrée qui est un processus complexe multiséquentiel faisant intervenir de nombreux facteurs cellulaires. Le virus se lie d’abord à la surface cellulaire via des facteurs d’attachement puis interagit avec des facteurs d’entrée spécifiques tels que la tétraspanine CD81, le récepteur scavenger B1 et les protéines de jonctions serrées CLDN-1, -6, -9 et OCLN. La particule virale est ensuite internalisée via une endocytose dépendante de la clathrine, puis sous l’action du pH acide des endosomes les enveloppes virale et cellulaire fusionnent permettant la libération de la capside virale dans le cytoplasme de la cellule infectée. Parmi les facteurs cellulaires impliqués dans l’entrée du HCV, deux protéines de la famille des tétraspanines ont été identifiées, CD81 et CD63. Les tétraspanines sont des protéines transmembranaires capables de former des microdomaines enrichis en tétraspanines en interagissant entre elles ainsi qu’avec des protéines dites partenaires. Nous avons testé l’implication dans l’entrée virale des tétraspanines exprimées dans les hépatocytes. Ainsi, nous avons montré que CD151 semble également important pour l’entrée du HCV. CD151 aurait un rôle indirect sur l’entrée en jouant sur l’organisation membranaire, en empêchant CD81 de former des clusters qui restreignent l’entrée du virus. Nous avons aussi étudié le rôle que pouvait jouer les polymorphismes de facteurs d’entrée sur l’entrée virale. Sur une cohorte de patients toxicomanes infectés par le HIV mais non infectés par le HCV, deux mutations ont été identifiées, R209Q dans CLDN-6 et P24A dans OCLN, qui n’étaient pas présentes dans les populations contrôles ou coinfectées par le HCV. Chez les patients toxicomanes, il est très rare que les patients infectés par le HIV ne le soient pas par le HCV, suggérant une résistance naturelle de ces patients à l’infection. Nous avons émis l’hypothèse que ces deux mutations pouvaient bloquer l’entrée du HCV. Cependant, la caractérisation de ces mutations a montré qu’elles n’avaient pas d’effet fonctionnel in vitro. Enfin, nous avons exploré l’effet de la Monensine, un ionophore polyéther, sur l’infection par le HCV. Cette molécule augmente le pH des endosomes via ses capacités de transfert d’ions à travers les membranes cellulaires. Nous avons montré qu’elle inhibe l’entrée du HCV en bloquant la fusion. De manière intéressante, la transmission cellule-cellule, un mécanisme d’entrée du virus encore mal caractérisé, était également bloquée par la Monensine, suggérant une étape de fusion dépendante du pH pour cette voie. Nous avons généré des mutants de résistance à la Monensine, notamment le clone FL-8 qui portait deux mutations dans les glycoprotéines d’enveloppe, Y297H dans E1 et I399T dans E2. Les particules virales portant ces deux mutations infectaient les cellules de manière indépendante du pH, présentaient des propriétés physicochimiques différentes et ne se transmettaient plus de cellule à cellule. En conclusion ces études soulignent l’importance de l’organisation membranaire pour l’entrée du virus via certains facteurs cellulaires tels que CD151. Par ailleurs, nous avons mis en évidence que la transmission cellule-cellule était dépendante du pH et que des mutations ponctuelles dans E1 et E2 permettent une fusion indépendante du pH. En revanche, des polymorphismes naturels de CLDN-6 et OCLN n’affectent pas leur capacité à supporter l’entrée virale. / Hepatitis C Virus (HCV) is a global health problem with over 170 million infected people worldwide. HCV targets mainly the hepatocytes and its lifecycle is divided into three steps. Viral particle entry leads to the release of viral genomic RNA into the cytoplasm where translation and replication take place. Then, new viral particles are assembled and secreted. During my thesis, we focused on the entry step. Indeed, HCV entry is a complex multistep process that requires numerous cellular factors. First, the virus interacts with attachment factors and then interacts with specific cellular factors including the tetraspanin CD81, the scavenger receptor B1 and the tight junction proteins CLDN-1, -6, -9 and OCLN. The viral particle is next internalized through a clathrin-dependent endocytosis. Finally, fusion at low pH occurs between viral and endosomal membranes leading to the release of the capsid into the cytoplasm. Among cellular factors involved in HCV entry, two members of the tetraspanin superfamily were identified, CD81 and CD63. Tetraspanins are transmembrane proteins able to organize themselves in tetraspanin-enriched microdomains through tetraspanin-tetraspanin interactions and interactions with partner proteins. We tested the involvement in HCV entry of tetraspanins expressed in hepatocytes. Interestingly, we showed that CD151 is also involved in HCV entry. CD151 seems to play an indirect role in HCV entry through regulating membrane organization, especially by preventing CD81 clustering, which is unfavourable to HCV entry. We also studied the effect of some entry factors polymorphisms on viral entry. In a cohort of drug users infected by HIV but not by HCV, we identified two mutations, R209Q in CLDN-6 and P24A in OCLN, not found in control or coinfected patients. It is very rare for drug users patients infected by HIV not to be infected by HCV, suggesting a natural resistance of these patients to HCV infection. We hypothesized that the two mutations identified might impair HCV entry. However, the characterization of these mutations showed that they did not have a functional effect in vitro. Finally, we investigated the effect of Monensin, a polyether ionophore, on viral entry. This molecule increases endosomal pH through its ions transfer properties across cell membranes. We showed that Monensin inhibits HCV entry through impairing the fusion step. Interestingly, HCV cell-to-cell transmission, another poorly characterized entry pathway, was also blocked by Monensin, suggesting that a pH-dependent fusion step is also required for this transmission route. We generated resistant mutants to Monensin, notably the FL-8 mutant carrying two mutations in envelope glycoproteins, namely Y297H in E1 and I399T in E2. Viral particles expressing these two mutations infected cells in a pH-independent manner, displayed different biophysical properties and were not cell-to-cell transmitted. To conclude, these studies highlight the importance of membrane organization for viral entry through cell factors like CD151. We also pointed out that cell-to-cell transmission is a pH-dependent process. In addition, point mutations in E1 and E2 are sufficient to enable HCV to be pH-independent for its entry. However, polymorphisms in CLDN-6 and OCLN seem to have no effect on viral entry.
90

Zavedení nového výrobku na trh / New product launch

Andžič, Vedrana January 2011 (has links)
The aim of this Master's thesis is description of new electric water heater launch process. The theoretical part of the thesis deals with marketing mix and goes deeper in explanation of product lifecycle theory. Theoretical part is the basis for practical part. Practical part describes company Ariston Thermo in brief and deals with technical parameters of new electric water heater VELIS as well as distribution and price policy during the launch process. The key part of the thesis is dedicated to analysis of communication mix tools used during the first phase of product lifecycle, it's costs and impact. There is a short recommendation for growth phase in conclusion of the thesis.

Page generated in 0.0543 seconds