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摘要 隨著時代變遷，行銷手法愈來愈推陳出新，商品零售市場的競爭也愈來愈激烈，走進零售店會看到二件八折，第二件五折或是買一送一等降價促銷活動；剛開始做第二件五折的時候，業績瞬間成長，但是多做幾次之後，效益可能就開始往下降，因此可能開始加碼做買一送一，或是增加降價促銷的頻率，最後無法抽身，而陷入一個不得不做的僵局。所以，如何訂定適當的行銷策略，在價格促銷深度和頻率間取得平衡點，追求最大的效益，是製造商常常面臨的問題與決策。 本研究使用尼爾森量販店商品掃描資料，以餅乾銷售資料做為研究品類，探討價格促銷深度與頻率的相互關係，如何影響消費者購買趨勢。本研究根據迴歸線性模型，利用銷售資料先了解前期、節慶及競爭者等變數對該品類的影響，再分析不同的促銷折扣下的價格彈跳幅度，最後分別以二個月及三個月為單位搭配促銷的頻率，看前期有無促銷的時候，對最後一個月不同的價格促銷深度時的業績增加幅度影響。 最後以消費者預期下一次促銷時間與預期價格差異的行為理論，針對本研究結果做分析，提供行銷建議。

The continuously increasing demand for clean renewable energy has rekindled interest in multi-terminal high voltage direct current (HVDC) grids. Although such grids have several advantages and a great potential, their materialization has been thwarted due to the absence of HVDC breakers. In comparison with traditional alternating current (AC) breakers, they should operate and interrupt fault currents in a time frame of a few milliseconds. The aim of this thesis is focused on the design of ultra-fast electro-mechanical actuator systems suitable for such HVDC breakers.Initially, holistic multi-physics and hybrid models with different levels of complexity and computation time were developed to simulate the entire switch. These models were validated by laboratory experiments. Following a generalized analysis, in depth investigations involving simulations complemented with experiments were carried out on two of the sub-components of the switch: the ultra-fast actuator and the damper. The actuator efficiency, final speed, peak current, and maximum force were explored for different design data.The results show that models with different levels of complexity should be used to model the entire switch based on the magnitude of the impulsive forces. Deformations in the form of bending or elongation may deteriorate the efficiency of the actuator losing as much as 35%. If that cannot be avoided, then the developed first order hybrid model should be used since it can simulate the behavior of the mechanical switch with a very good accuracy. Otherwise, a model comprising of an electric circuit coupled to an electromagnetic FEM model with a simple mechanics model, is sufficient.It has been shown that using a housing made of magnetic material such as Permedyn, can boost the efficiency of an actuator by as much as 80%. In light of further optimizing the ultra-fast actuator, a robust optimization algorithm was developed and parallelized. In total, 20520 FEM models were computed successfully for a total simulation time of 7 weeks. One output from this optimization was that a capacitance of 2 mF, a charging voltage of 1100 V and 40 turns yields the highest efficiency (15%) if the desired velocity is between 10 m/s and 12 m/s.The performed studies on the passive magnetic damper showed that the Halbach arrangement gives a damping force that is two and a half times larger than oppositely oriented axially magnetized magnets. Furthermore, the 2D optimization model showed that a copper thickness of 1.5 mm and an iron tube that is 2 mm thick is the optimum damper configuration. / <p>QC 20150422</p>

Robust preconditioners on block-triangular and block-factorized form for three types of linear systems of two-by-two block form are studied in this thesis. The first type of linear systems, which are dense, arise from a boundary element type of discretization of crack propagation problems. Numerical experiment show that simple algebraic preconditioning strategies results in iterative schemes that are highly competitive with a direct solution method. The second type of algebraic systems, which are sparse, indefinite and nonsymmetric, arise from a finite element (FE) discretization of the partial differential equations (PDE) that describe (visco)elastic glacial isostatic adjustment (GIA). The Schur complement approximation in the block preconditioners is constructed by assembly of local, exactly computed Schur matrices. The quality of the approximation is verified in numerical experiments. When the block preconditioners for the indefinite problem are combined with an inner iterative scheme preconditioned by a (nearly) optimal multilevel preconditioner, the resulting preconditioner is (nearly) optimal and robust with respect to problem size, material parameters, number of space dimensions, and coefficient jumps. Two approaches to mathematically formulate the PDEs for GIA are compared. In the first approach the equations are formulated in their full complexity, whereas in the second their formulation is confined to the features and restrictions of the employed FE package. Different solution methods for the algebraic problem are used in the two approaches. Analysis and numerical experiments reveal that the first strategy is more accurate and efficient than the latter. The block structure in the third type of algebraic systems is due to a fine-coarse splitting of the unknowns. The inverse of the pivot block is approximated by a sparse matrix which is assembled from local, exactly inverted matrices. Numerical experiments and analysis of the approximation show that it is robust with respect to problem size and coefficient jumps.

In recent times, light gauge cold-formed steel sections have been used extensively in residential, industrial and commercial buildings as primary load bearing structural components. This is because cold-formed steel sections have a very high strength to weight ratio compared with thicker hot-rolled steel sections, and their manufacturing process is simple and cost-effective. However, these members are susceptible to various buckling modes including local and distortional buckling and their ultimate strength behaviour is governed by these buckling modes. Fire safety design of building structures has received greater attention in recent times due to continuing loss of properties and lives during fires. Hence, there is a need to fully evaluate the performance of light gauge cold-formed steel structures under fire conditions. Past fire research has focused heavily on heavier, hot-rolled steel members. The buckling behaviour of light gauge cold-formed steel members under fire conditions is not well understood. The buckling effects associated with thin steels are significant and have to be taken into account in fire safety design. Therefore, a research project based on extensive experimental and numerical studies was undertaken at the Queensland University of Technology to investigate the distortional buckling behaviour of light gauge cold-formed steel compression members under simulated fire conditions. As the first phase of this research program more than 115 tensile coupon tests of light gauge cold-formed steels including two steel grades and five thicknesses were conducted at elevated temperatures. Accurate mechanical properties including the yield strength, elasticity modulus and stress-strain curves were all determined at elevated temperatures since the deterioration of the mechanical properties is one of the major parameters in the structural design under fire conditions. An appropriate stress-strain model was also developed by considering the inelastic characteristics. The results obtained from the tensile coupon tests were then used to predict the ultimate strength of cold-formed steel compression members. In the second phase of this research more than 170 laboratory experiments were undertaken to investigate the distortional buckling behaviour of light gauge coldformed steel compression members at ambient and elevated temperatures. Two types of cross sections were selected with various thicknesses (nominal thicknesses are 0.6, 0.8, and 0.95 mm) and both low and high strength steels (G250 and G550 steels with minimum yield strengths of 250 and 550 MPa). The experiments were conducted at six different temperatures in the range of 20 to 800°C. A finite element model of the tested compression members was then developed and validated with the help of experimental results. The degradation of mechanical properties with increasing temperatures was included in finite element analyses. An extensive series of parametric analyses was undertaken using the validated finite element model to investigate the effect of all the influential parameters such as section geometry, steel thickness and grade, mechanical properties and temperature. The resulting large data base of ultimate loads of compression members subject to distortional buckling was then used to review the adequacy of the current design rules at ambient temperature. The current design rules were reasonably accurate in general, but in order to improve the accuracy further, this research has developed new design equations to determine the ultimate loads of compression members at ambient temperature. The developed equation was then simply modified by including the relevant mechanical properties at elevated temperatures. It was found that this simple modification based on reduced mechanical properties gave reasonable results, but not at higher temperatures. Therefore, they were further modified to obtain a more accurate design equation at elevated temperatures. The accuracy of new design rules was then verified by comparing their predictions with the results obtained from the parametric study. This thesis presents a description of the experimental and numerical studies undertaken in this research and the results including comparison with simply modified current design rules. It describes the laboratory experiments at ambient and elevated temperatures. It also describes the finite element models of cold-formed steel compression members developed in this research that included the appropriate mechanical properties, initial geometric imperfections and residual stresses. Finally, it presents the details of the new design equations proposed for the light gauge coldformed steel compression members subjected to distortional buckling effects at elevated temperatures.

Cold-formed steel members have been widely used in residential, industrial and commercial buildings as primary load bearing structural elements and non-load bearing structural elements (partitions) due to their advantages such as higher strength to weight ratio over the other structural materials such as hot-rolled steel, timber and concrete. Cold-formed steel members are often made from thin steel sheets and hence they are more susceptible to various buckling modes. Generally short columns are susceptible to local or distortional buckling while long columns to flexural or flexural-torsional buckling. Fire safety design of building structures is an essential requirement as fire events can cause loss of property and lives. Therefore it is essential to understand the fire performance of light gauge cold-formed steel structures under fire conditions. The buckling behaviour of cold-formed steel compression members under fire conditions is not well investigated yet and hence there is a lack of knowledge on the fire performance of cold-formed steel compression members. Current cold-formed steel design standards do not provide adequate design guidelines for the fire design of cold-formed steel compression members. Therefore a research project based on extensive experimental and numerical studies was undertaken at the Queensland University of Technology to investigate the buckling behaviour of light gauge cold-formed steel compression members under simulated fire conditions. As the first phase of this research, a detailed review was undertaken on the mechanical properties of light gauge cold-formed steels at elevated temperatures and the most reliable predictive models for mechanical properties and stress-strain models based on detailed experimental investigations were identified. Their accuracy was verified experimentally by carrying out a series of tensile coupon tests at ambient and elevated temperatures. As the second phase of this research, local buckling behaviour was investigated based on the experimental and numerical investigations at ambient and elevated temperatures. First a series of 91 local buckling tests was carried out at ambient and elevated temperatures on lipped and unlipped channels made of G250-0.95, G550-0.95, G250-1.95 and G450-1.90 cold-formed steels. Suitable finite element models were then developed to simulate the experimental conditions. These models were converted to ideal finite element models to undertake detailed parametric study. Finally all the ultimate load capacity results for local buckling were compared with the available design methods based on AS/NZS 4600, BS 5950 Part 5, Eurocode 3 Part 1.2 and the direct strength method (DSM), and suitable recommendations were made for the fire design of cold-formed steel compression members subject to local buckling. As the third phase of this research, flexural-torsional buckling behaviour was investigated experimentally and numerically. Two series of 39 flexural-torsional buckling tests were undertaken at ambient and elevated temperatures. The first series consisted 2800 mm long columns of G550-0.95, G250-1.95 and G450-1.90 cold-formed steel lipped channel columns while the second series contained 1800 mm long lipped channel columns of the same steel thickness and strength grades. All the experimental tests were simulated using a suitable finite element model, and the same model was used in a detailed parametric study following validation. Based on the comparison of results from the experimental and parametric studies with the available design methods, suitable design recommendations were made. This thesis presents a detailed description of the experimental and numerical studies undertaken on the mechanical properties and the local and flexural-torsional bucking behaviour of cold-formed steel compression member at ambient and elevated temperatures. It also describes the currently available ambient temperature design methods and their accuracy when used for fire design with appropriately reduced mechanical properties at elevated temperatures. Available fire design methods are also included and their accuracy in predicting the ultimate load capacity at elevated temperatures was investigated. This research has shown that the current ambient temperature design methods are capable of predicting the local and flexural-torsional buckling capacities of cold-formed steel compression members at elevated temperatures with the use of reduced mechanical properties. However, the elevated temperature design method in Eurocode 3 Part 1.2 is overly conservative and hence unsuitable, particularly in the case of flexural-torsional buckling at elevated temperatures.

This thesis explores whether scanner data can be used to inform Consumer Price Index (CPI) construction, with particular reference to the issues of substitution bias and choice of aggregation dimensions. The potential costs and benefits of using scanner data are reviewed. Existing estimates of substitution bias are found to show considerable variation. An Australian scanner data set is used to estimate substitution bias for six different aggregation methods and for fixed base and superlative indexes. Direct and chained indexes are also calculated. Estimates of substitution bias are found to be highly sensitive to both the method of aggregation used and whether direct or chained indexes were used. The ILO (2004) recommends the use of dissimilarity indexes to determine the issue of when to chain. This thesis provides the first empirical study of dissimilarity indexes in this context. The results indicate that dissimilarity indexes may not be sufficient to resolve the issue. A Constant Elasticity of Substitution (CES) index provides an approximate estimate of substitution-bias-free price change, without the need for current period expenditure weights. However, an elasticity parameter is needed. Two methods, referred to as the algebraic and econometric methods, were used to estimate the elasticity parameter. The econometric approach involved the estimation of a system of equations proposed by Diewert (2002a). This system has not been estimated previously. The results show a relatively high level of substitution at the elementary aggregate level, which supports the use a Jevons index, rather than Carli or Dutot indexes, at this level. Elasticity parameter estimates were found to vary considerably across time, and statistical testing showed that elasticity parameter estimates were significantly different across estimation methods. Aggregation is an extremely important issue in the compilation of the CPI. However, little information exists about 'appropriate' aggregation methods. Aggregation is typically recommended over 'homogenous' units. An hedonic framework is used to test for item homogeneity across four supermarket chains and across all stores within each chain. This is a novel approach. The results show that treating the same good as homogenous across stores which belong to the same chain may be recommended.

Made available in DSpace on 2016-06-02T19:33:12Z (GMT). No. of bitstreams: 1 SILVA_Maria_Aparecida_2013.pdf: 1779146 bytes, checksum: 4286b3a26b02309aed6d6018eb2386bd (MD5) Previous issue date: 2013-05-21 / This thesis aims to investigate the relations of substitution between Saving Accounts and DI Funds during the period of December 2004 and December 2012. The Brazilian basic interest rate SELIC rate has reduced over 10 percentage points during this period. Such a downward movement affected the returns on financial assets, i.e., their "prices", defined as opportunity costs in relation to the SELIC rate. The hypothesis is that substitution relationship between Saving Accounts and DI Funds have changed over time due to different levels of SELIC rate prevailing during the analyzed period. The dual approach and the nonlinear seemingly unrelated equations model (INSUR model) are used to estimate the demands via Translog functional form. Morishima elasticities of substitution are calculated in seven points of the sample in order to measure the substitution effect over the time and to evaluate possible asymmetry of elasticities. The results confirm the hypothesis that different levels of SELIC have engendered different patterns of relations of substitution between the analyzed assets. The conclusion is that the anew relations of substitution have expanded the role of Saving Accounts as instrument of private savings over DI Funds. / O objetivo deste estudo é investigar as relações de substituição entre as Cadernetas de Poupança e os Fundos DI, entre dezembro de 2004 e dezembro de 2012, período marcado pela redução na taxa básica de juros brasileira taxa SELIC em mais de 10 pontos percentuais. Esta queda acentuada afetou as rentabilidades dos ativos financeiros, i.e., seus preços , definidos aqui em termos de custos de oportunidades em relação à própria taxa SELIC. A hipótese do trabalho é que as relações de substituição entre Cadernetas de Poupança e Fundos DI se alteraram motivadas pelos diferentes níveis de taxa SELIC praticados ao longo do período analisado. Emprega-se a abordagem dual e o modelo não linear de equações aparentemente não relacionadas (sigla em inglês, INSUR) para estimar as demandas via a forma funcional Translog. As elasticidades de substituição de Morishima são calculadas em sete pontos médios da amostra, visando avaliar a evolução das magnitudes das relações de substituição ao longo do tempo, bem como sua possível assimetria. Os resultados obtidos confirmam a hipótese de que diferentes níveis de taxa SELIC engendram padrões de relações de substituição diversos entre os dois bens monetários analisados. Conclui-se que as diferentes relações de substituição verificadas levaram à ampliação do papel das Cadernetas de Poupança como instrumentos de poupança privada em detrimento dos Fundos DI.

With the widespread use of the Internet, the popularity of web applications has significantly increased. Such applications are subject to unpredictable workload conditions that vary from time to time. For example, an e-commerce website may face higher workloads than normal during festivals or promotional schemes. Such applications are critical and performance related issues, or service disruption can result in financial losses. Cloud computing with its attractive feature of dynamic resource provisioning (elasticity) is a perfect match to host such applications. The rapid growth in the usage of cloud computing model, as well as the rise in complexity of the web applications poses new challenges regarding the effective monitoring and management of the underlying cloud computational resources. This thesis investigates the state-of-the-art elastic methods including the models and techniques for the dynamic management and provisioning of cloud resources from a service provider perspective. An elastic controller is responsible to determine the optimal number of cloud resources, required at a particular time to achieve the desired performance demands. Researchers and practitioners have proposed many elastic controllers using versatile techniques ranging from simple if-then-else based rules to sophisticated optimisation, control theory and machine learning based methods. However, despite an extensive range of existing elasticity research, the aim of implementing an efficient scaling technique that satisfies the actual demands is still a challenge to achieve. There exist many issues that have not received much attention from a holistic point of view. Some of these issues include: 1) the lack of adaptability and static scaling behaviour whilst considering completely fixed approaches; 2) the burden of additional computational overhead, the inability to cope with the sudden changes in the workload behaviour and the preference of adaptability over reliability at runtime whilst considering the fully dynamic approaches; and 3) the lack of considering uncertainty aspects while designing auto-scaling solutions. This thesis seeks solutions to address these issues altogether using an integrated approach. Moreover, this thesis aims at the provision of qualitative elasticity rules. This thesis proposes a novel biologically-inspired switched feedback control methodology to address the horizontal elasticity problem. The switched methodology utilises multiple controllers simultaneously, whereas the selection of a suitable controller is realised using an intelligent switching mechanism. Each controller itself depicts a different elasticity policy that can be designed using the principles of fixed gain feedback controller approach. The switching mechanism is implemented using a fuzzy system that determines a suitable controller/- policy at runtime based on the current behaviour of the system. Furthermore, to improve the possibility of bumpless transitions and to avoid the oscillatory behaviour, which is a problem commonly associated with switching based control methodologies, this thesis proposes an alternative soft switching approach. This soft switching approach incorporates a biologically-inspired Basal Ganglia based computational model of action selection. In addition, this thesis formulates the problem of designing the membership functions of the switching mechanism as a multi-objective optimisation problem. The key purpose behind this formulation is to obtain the near optimal (or to fine tune) parameter settings for the membership functions of the fuzzy control system in the absence of domain experts’ knowledge. This problem is addressed by using two different techniques including the commonly used Genetic Algorithm and an alternative less known economic approach called the Taguchi method. Lastly, we identify seven different kinds of real workload patterns, each of which reflects a different set of applications. Six real and one synthetic HTTP traces, one for each pattern, are further identified and utilised to evaluate the performance of the proposed methods against the state-of-the-art approaches.

Submitted by Raniere Barreto (raniere.barros@ufvjm.edu.br) on 2018-05-07T18:19:12Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) s?lvio_luiz_figueiredo.pdf: 1948091 bytes, checksum: 9615d43a375d54bc9dbbf67d8bec0dfb (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-05-14T14:29:30Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) s?lvio_luiz_figueiredo.pdf: 1948091 bytes, checksum: 9615d43a375d54bc9dbbf67d8bec0dfb (MD5) / Made available in DSpace on 2018-05-14T14:29:30Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) s?lvio_luiz_figueiredo.pdf: 1948091 bytes, checksum: 9615d43a375d54bc9dbbf67d8bec0dfb (MD5) Previous issue date: 2017 / O trabalho tem como objetivo estimar a demanda de ?gua do sistema de abastecimento p?blico da Cidade de Te?filo Otoni ? MG, bem como examinar os efeitos das vari?veis determinantes em seu comportamento. Permite ainda uma compreens?o do cen?rio pesquisado, possibilitando, deste modo, analisar a magnitude de poss?veis pol?ticas tarif?rias utilizadas, sendo capaz de sustentar no processo decis?rio sobre a necessidade de investimentos, por meio de proje??es do consumo. Para esse fim, utilizou-se t?cnicas de an?lise explorat?ria temporal de dados, considerando o per?odo de setembro de 2012 a dezembro de 2014, dividida em duas categorias de consumo: social e normal. O modelo de demanda de ?gua apoiou-se na estrutura tarif?ria da Companhia de Saneamento de Minas Gerais (COPASA-MG), visando avaliar aspectos importantes tanto para o servi?o de abastecimento de ?gua quanto de consumidores. Ressalta-se a import?ncia das vari?veis pre?o m?dio, renda e clima, objetivando-se substancialmente em encontrar os par?metros de elasticidade. A compreens?o desses par?metros viabiliza uma an?lise do impacto de pol?ticas tarif?rias e possibilita a proje??o do consumo futuro de ?gua no longo prazo. Os resultados encontrados destacam a inelasticidade pre?o da demanda de ?gua para ambas categorias estudadas, apresentando coeficientes significativos para o pre?o marginal e a vari?vel diferen?a. A quantidade de ?gua defasada e a renda para ambas as categorias estudadas, n?o apresentaram o sinal esperado pela literatura; j? o clima, na categoria normal, o coeficiente n?o foi significativo estatisticamente; e na categoria social, o coeficiente mostrou-se significativo. Portanto, presume-se um maior conhecimento na estrutura tarif?ria da cidade, al?m da busca por vari?veis que expliquem melhor a demanda de ?gua. / Disserta??o (Mestrado Profissional) ? Programa de P?s-Gradua??o em Tecnologia, Sa?de e Sociedade, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / The objective of this work is to estimate the water demand of the Te?filo Otoni - MG public water supply system, as well as to examine the effects of the determinant variables on its behavior. It also allows an understanding of the researched scenario, thus making it possible to analyze the magnitude of possible tariff policies used, being able to sustain in the decision making process on the need for investments, through consumption projections. For this purpose, we used techniques for exploratory temporal data analysis, considering the period from September 2012 to December 2014, divided into two categories of consumption: social residential and normal residential. The water demand model was based on the tariff structure of the Minas Gerais Sanitation Company (COPASA-MG), in order to evaluate important aspects for both the water supply service and consumers. The significance of the variables average price, income and climate is emphasized, aiming substantially at finding the parameters of elasticity. The understanding of these parameters enables an analysis of the impact of tariff policies and enables the projection of future water consumption in the long term. The results found highlight the price inelasticity of water demand for both categories studied, presenting significant coefficients for the marginal price and the difference variable. The coefficient was not statistically significant, in the social category, the coefficient showed to be highly significant. The coefficient was not statistically significant, in the social category, the coefficient showed to be highly significant. Therefore, it is assumed a greater knowledge in the tariff structure of the city, besides the search for variables that better explain the water demand.