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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.
1

Lipoprotein lipase-unstable on purpose?

Zhang, Liyan January 2007 (has links)
Lipoprotein lipase (LPL) is a central enzyme in lipid metabolism. It is a non-covalent, homodimeric and N-glycosylated protein, which is regulated in a tissue-specific manner and is dependent on an activator protein, apolipoprotein CII. Dissociation of active LPL dimers to monomers leads to loss of activity. This was previously found to be an important event in the rapid regulation of LPL in tissues. The mechanisms involved in the processing of LPL to active dimers, as well as in LPL inactivation through monomerization, were unknown. We have investigated the folding properties of the LPL protein, in particular the requirements for LPL to attain its active quaternary structure and to remain in the native conformation. On expression of LPL in insect cells we found that most of the LPL protein was synthesized in an inactive monomeric form. By co-expression of LPL with human molecular haperones, especially with calreticulin (CRT), the activity of LPL increased greatly, both in the cells and in the media. The effect of CRT on LPL activity was not due to increased levels of the LPL protein, but was due to an increased proportion of active dimeric LPL. Co-immunoprecipitation experiments showed direct interaction between LPL and CRT supporting the idea that this ER-based molecular chaperone supports the formation of active LPL dimers. We showed that, bis-ANS, the aromatic hydrophobic probe 1,1.-bis(aniline)-4,4.- bis(naphthalene)-8,8.disulfonate, can be used to obtain specific information about the interaction of LPL with lipid substrates and with apoCII. Bis-Ans was found to be a potent inhibitor of LPL activity, but apoCII prevented the inhibition. Our results suggest that bis-Ans binds to three exposed hydrophobic sites, of which one is at or close to the binding site(s) for apoCII. In studies of the mechanisms responsible for the spontaneous inactivation of LPL, we showed that active LPL is a dynamic dimer in which the subunits rapidly exchange partners. The rapid equilibrium between dimers and monomers exists even under conditions where LPL is relatively stable. This supports the idea that the dimer is in equilibrium with dimerization-competent, possibly active monomers. This dimerization-competent intermediate was also implicated in studies of the inactivation kinetics. The inactive LPL monomer was found to have a stable, defined conformation irrespective of how it was formed. The main differences in conformation between the inactive monomer and the active dimer were located in the middle part of the LPL subunit. Experiments with bis-Ans demonstrated that more hydrophobic regions were exposed in the inactive monomer, indicating a molten globule conformation. We concluded that the middle part of the LPL subunit is most likely engaged in the formation of the active LPL dimer. The dimerization-competent LPL monomer is a hypothetical conformational state, because it has not been possible to isolate it. To study complete refolding of LPL we used fully denatured LPL and were able to demonstrate that the recovery of LPL activity was about 40% when the denaturant was diluted by a buffer containing 20% human serum and 2M NaCl. Further studies identified calcium as the component in serum that was crucial for the reactivation of LPL. The refolding of LPL was shown to involve at least two steps, of which the first one was rapid and resulted in folded, but inactive monomers. The second step, from inactive monomers to active dimers, was slow and calcium-dependent. Also inactive monomers isolated from human tissue were able to recover activity under the influence of calcium. We proposed that calcium-dependent control of LPL dimerization might be involved in the normal post-translational regulation of LPL activity. In conclusion, LPL is a relatively unstable enzyme under physiological conditions due to its noncovalent dimeric structure. The energy barrier for folding to the active dimer is high and requires the presence of calcium ions and molecular chaperones to be overcome. The dimeric arrangement is probably essential to accomplish rapid down-regulation of LPL activity according to metabolic demand, e.g. in adipose tissue on fasting.
2

The use of Big Data Analytics to protect Critical Information Infrastructures from Cyber-attacks

Oseku-Afful, Thomas January 2016 (has links)
Unfortunately, cyber-attacks, which are the consequence of our increasing dependence on digital technology, is a phenomenon that we have to live with today. As technology becomes more advanced and complex, so have the types of malware that are used in these cyber-attacks. Currently, targeted cyber-attacks directed at CIIs such as financial institutions and telecom companies are on the rise. A particular group of malware known as APTs, which are used for targeted attacks, are very difficult to detect and prevent due to their sophisticated and stealthy nature. These malwares are able to attack and wreak havoc (in the targeted system) within a matter of seconds; this is very worrying because traditional cyber security defence systems cannot handle these attacks. The solution, as proposed by some in the industry, is the use of BDA systems. However, whilst it appears that BDA has achieved greater success at large companies, little is known about success at smaller companies. Also, there is scarcity of research addressing how BDA is deployed for the purpose of detecting and preventing cyber-attacks on CII. This research examines and discusses the effectiveness of the use of BDA for detecting cyber-attacks and also describes how such a system is deployed. To establish the effectiveness of using a BDA, a survey by questionnaire was conducted. The target audience of the survey were large corporations that were likely to use such systems for cyber security. The research concludes that a BDA system is indeed a powerful and effective tool, and currently the best method for protecting CIIs against the range of stealthy cyber-attacks. Also, a description of how such a system is deployed is abstracted into a model of meaningful practice.
3

Multilevel Space Vector PWM for Multilevel Coupled Inductor Inverters

Vafakhah, Behzad 06 1900 (has links)
A multilevel Space Vector PWM (SVPWM) technique is developed for a 3-level 3-phase PWM Voltage Source Inverter using a 3-phase coupled inductor to ensure high performance operation. The selection of a suitable PWM switching scheme for the Coupled Inductor Inverter (CII) topology should be based on the dual requirements for a high-quality multilevel PWM output voltage together with the need to minimize high frequency currents and associated losses in the coupled inductor and the inverter switches. Compared to carrier-based multilevel PWM schemes, the space vector techniques provide a wider variety of choices of the available switching states and sequences. The precise identification of pulse placements in the SVPWM method is used to improve the CII performance. The successful operation of the CII topology over the full modulation range relies on selecting switching states where the coupled inductor presents a low winding current ripple and a high effective inductance between the upper and lower switches in each inverter leg. In addition to these requirements, the CII operation is affected by the imbalance inductor common mode dc current. When used efficiently, SVPWM allows for an appropriate balance between the need to properly manage the inductor winding currents and to achieve harmonic performance gains. A number of SVPWM strategies are developed, and suitable switching states are selected for these methods. Employing the interleaved PWM technique by using overlapping switching states, the interleaved Discontinuous SVPWM (DSVPWM) method, compared to other proposed SVPWM methods, doubles the effective switching frequency of the inverter outputs and, as a result, offers superior performance for the CII topology by reducing the inductor losses and switching losses. The inverter operation is examined by means of simulation and experimental testing. The experimental performance comparison is obtained for different PWM switching patterns. The inverter performance is affected by high-frequency inductor current ripple; the excessive inductor losses are reduced by the DSVPWM method. Additional experimental test results are carried out to obtain the inverter performance as a variable frequency drive when operated in steady-state and during transient conditions. The CII topology is shown to have great potential for variable speed drives. / Power Engineering and Power Electronics
4

Multilevel Space Vector PWM for Multilevel Coupled Inductor Inverters

Vafakhah, Behzad Unknown Date
No description available.
5

A expansão das commodities e a suposta desindustrialização na região nordeste do Brasil no período 1991-2012

Souza, Kamille Leão de January 2013 (has links)
SOUZA, Kamille Leão de. A expansão das commodities e a suposta desindustrialização na região Nordeste do Brasil no período 1991-2012. 2013. 127 f.: Dissertação (mestrado) - Universidade Federal do Ceará. Mestrado Acadêmico em Economia Rural (MAER). Centro de Ciências Agrárias. Fortaleza-CE. 2013 / Submitted by Francisco Helder Macêdo Rangel (fhelder@ufc.br) on 2014-10-10T17:07:16Z No. of bitstreams: 1 2013_dis_klsouza.pdf: 1329267 bytes, checksum: 189bb2778404c732a679703c10dc924a (MD5) / Approved for entry into archive by Margareth Mesquita(margaret@ufc.br) on 2014-12-03T15:54:37Z (GMT) No. of bitstreams: 1 2013_dis_klsouza.pdf: 1329267 bytes, checksum: 189bb2778404c732a679703c10dc924a (MD5) / Made available in DSpace on 2014-12-03T15:54:37Z (GMT). No. of bitstreams: 1 2013_dis_klsouza.pdf: 1329267 bytes, checksum: 189bb2778404c732a679703c10dc924a (MD5) Previous issue date: 2013 / Nowadays deindustrialization underway in economies that have not yet reached a high per capita income is the main theme in debates. Several studies were conducted to Brazil on this subject, but the Northeast still lacks analysis in this area. The central hypothesis of this study is to verify ig the Northeast economy was deindustrialized in the period 1991-2012, from the continued growth of commodities in totalexports couopled with the highest share of products with higher technological content in the imports. The analysis was carried out by using data on the trade balance, exports and imports, registering the share of commodities and industrial products, according to the classification adopted by OECD and MDI C (high, medium-high, medium-low, low-tech and unprocessed products), the value added by industry, the share of manufacturing employment and total income (GDP). To this end, we calculated indicators foreign trade (Export Concentration Index-ICX, Concentration Index of Import-ICM, Revealed Comparative Advantage Index over the trade balance-VCR, simple rate of coverage of imports and TC-Index of intra-industrytrade-CII and an econometric model was regressed to verify traces of deindustrialization in relation to industrial production. The results indicate that the northeast export tariff undergoes a reprimarization that, when associated with the increased presence of industrial products with higher technological content of imports, show signs of deindustrialization. However, it is not possible to come to the conclusion that the northeast economy suffers the dutch disease because signs of loss of importance on the industrial sector in total did not appear on the analysis of industrial employment and of the value added by industry in the totaleconomy. There, such results corroborated with the econometric model regressed. However, some industries (textile, clothing and accessories and machinery, equipment and material) showed a decreasing trend in the evolution of the physical industry production index, which may indicate a kind of loss. / Nos dias atuais, é tema dos principais debates a desindustrialização em curso nas economias que ainda não atingiram alta renda per capita. Vários estudos foram realizados no Brasil sobre o assunto, mas a região Nordeste ainda carece de análises nessa área. A hipótese central deste estudo é verificar se a economia nordestina se desindustrializou no per5íodo 1991-2012, com o crescimento contínuo de commodities na pauta de exportações, aliado à maior participação de produtos de conteúdo tecnológico mais relevante na pauta de importações. A análise foi realizada fazendo uso de dados da balança comercial, exportação e importação, registrando a participação das commodities e dos produtos industriais segundo a classificação adotada pelo MDIC e OCDE (Ala, méida-alta, média-baixa, baixa intensidade tecnológica e produtos não industrializados), do valor agregado pela indústria, pela participação do emprego industrial no total e a renda (PIB). Para tal fim, foram calculados indicadores do comércio exterior (Índice de Concentração das Exportações-ICX, Índice de Concentração das Importações-ICM, Índice de Vantagem comparativa Revelada em relação ao saldo comerciakl-VCR, Taxa simples de Cobertura das importações-TC e o Índice de Comércio Intraindústria-CII) e regredido um modelo econométrico para verificar vestígios de desindustrialização concernente à produção industrial. Os resultados indicam que a pauta de exportação nordestina passa por uma reprimarização, que associada à maior presença de produtos industriais com maior conteúdo tecnológico nas importações apresenta sinais de desindustrialização. Não é possível concluir, no entanto, que a economia nordestina padeça da doença holandesa, pois, na análise do emprego industrial e do valor adicionado pela indústria no total da economia, não apareceram sinais de perda de importância do setor industrial no total, resultados esses corroborados pelo modelo econométrico regredido. Alguns segmentos industriais (têxtil, vestuário e acessórios, máquinas, aparelhos e materiais elétricos) expressam, contudo, uma tendência decrescente na evolução do índice de produção física industrial, o que pode indicar perda relativa desses ramos especificamente.
6

Ripples Across The Internet of Things : Context Metrics as Vehicles forRelational Self-Organization

Walters, Jamie January 2011 (has links)
The current paradigm shift in computing has placed mobile computation at the centre of focus. Users are now even more connected; demanding everything everywhere services. These services, such as social networking and media, benefit from the availability of context information seamlessly gathered and shared; providing customized and user-centric experiences. The distribution of context information no longer conforms to the paradigms of the existing Internet with regards to heterogeneity, connectivity and availability. This mandates new approaches towards its organization and provisioning in support of dependent applications and services. In response to these developments, the work summarized in this thesis addresses the fundamental problem of presenting context information in organized models as relevant subsets of global information. In approaching this problem, I introduced a distributed collection of context objects that can be arranged into simple relevant subsets called context schemata and presented to applications and services in supporting the realization of context based user experiences. Acknowledging the dynamic behaviour inherent of the real world interactions, I introduced an algorithm for measuring the proximities and similarities among these context objects, providing a metric through which to achieve organization. Additionally, I provided a means of ranking heterogeneous and distributed sensors in response to real time interaction between users and their digital ecosystem. Ranking provides an additional metric with which to achieve organization or identifying important and reputable information sources. The work I present here, additionally details my approach to realizing this complete behaviour an a distributed overlay, exploiting its properties for distribution, persistence and messaging. The overlay is also utilized for the provisioning of the supporting context information. Improvements in the ability to discover and attach new context information sources is fundamental to the ability to continually maintain expressions of context, derived from heterogeneous and disparate sources. By being able to create relevant subsets of organized data related to the requirements of applications and services in an end-point, infrastructures are realized for connecting and supporting the increasingly large numbers of users and their sources of information. Coupled with the distribution, these infrastructures realize improvements with regards to the effort required to achieve the same results. The culmination of the work presented in this thesis is an effort to enable seamless context-centric solutions on a future Internet of Things and thus constituting an adequate solution to the challenges raised above.
7

Demand Disaggregation for Non-Residential Water Users in the City of Logan, Utah, USA

Mahmoud Attaallah, Nour Aldin 01 December 2018 (has links)
Non-residential users contribute to a significant portion of the total water delivered by water supplying agencies. However, a very limited number of studies have attempted to investigate the water use behavior of non-residential users. With the emergence of newer “smart” meters, water use now can be measured and recorded at a very high temporal frequency. Smart meters can help determine total water use, timing, and component end uses to better understand water use practices by non-residential users. Water end use disaggregation is the process of separating the water used by each fixture or process within a facility. This is useful because having a breakdown of the consumption of all end uses may encourage users to consume less water and gives them indications on how to do so. This project involved collecting and working with three different datasets with three different temporal scales (monthly billing data, 5-minute water use data, and 5-second water use data). We analyzed monthly billing data to solicit potential participating facilities for the study. For each participating facility, new smart devices were installed on their existing water meters, including an advanced water meter register and a pulse counting data logger. The newer registers logged and transmitted data to a web-accessible data portal at 5-minute intervals, while the pulse counters recorded water use at 5- second intervals. These devices enabled us to measure the timing and volume of different water uses (e.g., indoor versus outdoor versus industrial processes uses). In this project, we identified different water use events, average water used by each end use (from plumbing fixtures to industrial machinery), variability in end uses (faucets/toilets versus showers), variability in use by the type of user (manufacturing facilities versus assisted living homes), and the impact of the business type on the water use.
8

Quantifying the colour appearance of displays

Kwak, Youngshin January 2003 (has links)
The LUTCHI data are the main colour appearance data used as the basis of many colour appearance models including CIECAM97s. It was shown in the LUTCHI data that projected colours are very different from reflective colours however there are relatively fewer data for projected colours than for reflective colours. In this study, it is intended to expand the colour appearance data of projected and self-luminous colours. The additional colours would then help investigate the performance of existing colour appearance models and, if necessary, enable the derivation of a new model to improve performance for projected and self-luminous colours. Before the colour appearance study, firstly the performances of the instruments and the displays used in the study were investigated. It was found that LCD displays perform very differently from CRT monitors. Two mathematical characterisation models for LCD displays were developed named S-Curve Model I and S-Curve Model II. The new colour appearance data set, CII-Kwak, was accumulated by a series of psychophysical experiments. The magnitude estimation technique was applied with the same experimental set-up as for LUTCHI experiments. The CII-Kwak data set has 20 phases with a total of 28,608 estimations covering various displays, luminance of a reference white, background luminance factors, surround conditions and stimulus sizes. Based on the CII-Kwak and the LUTCHI data set, the colour appearance phenomena were analysed. It was found that there are systematic colour appearance changes by the viewing factors investigated. Also eight colour appearance models were tested using the CII-Kwak and LUTCHI data sets. CIECAM97s-based models performed similarly well, but all models tested failed to predict several colour appearance changes, especially under dark surround conditions, which lead to suggest a new colour appearance model to have a better performance for colour appearance predictions. The Kwak03 model was derived from the CIECAM02 with several major modifications such as the cone signal ratios and the omission of the dynamic function. The Kwak03 model was shown to outperform all the other colour appearance models tested and also to be capable of predicting all colour appearance phenomena found in this study with good accuracy.
9

IP in the corridors of power : a study of lobbying, its impact on the development of intellectual property law, and the implications for the meaning of democracy

Adamson, Ben January 2017 (has links)
This thesis demonstrates that, while generally seen as a non-democratic activity, lobbying should in fact be viewed as an important part of democratic policymaking, providing valuable input into law and policy, particularly in areas where expertise is at a premium. Constructing a theoretical model of democracy and using the field of intellectual property as a focal point, the role of private actors is examined across a series of case studies: the 2011 Hargreaves Review of Intellectual Property and Growth, the 2010 Digital Economy Act, and the proposed 2002 EU Computer Implemented Inventions Directive. Each case study is based upon a combination of secondary sources and the first-hand experiences of certain actors involved and in each case the lobbying activity is critically evaluated in light of the features and normative conditions of the democratic model. This study ultimately shows both the positive aspects and negative aspects of lobbying from a democratic viewpoint, noting that the importance of stakeholder input into the law and policy that will affect those stakeholders is essential. It also shows, however, that equality of access to, and influence over, policymakers is far from satisfactory and that until such inequalities can be resolved, lobbying cannot be fully justified under my model of democracy.
10

Statistický výstup z asistovaných zhodnocení / Statistical output of security audits

Hrubešová, Gabriela January 2019 (has links)
The subject of this diploma thesis is a statistical analysis of security audits. The theoretical part describes key terms in the field of cyber and information security, basic background for this area and important regulations. The next part focuses on the description of security audit, its course, necessary conditions and content. The last part is devoted to statistical analysis of obtained samples. We analyse samples from several points of view, compare and look for features and information that could be helpful to the auditor’s assessment.

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