842 resultados para performance-based engineering


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El presente trabajo mide, en un contexto colaborativo, un conjunto de mecanismos relacionales interconectados y su incidencia en el performance organizacional. Apoyado en la Visión Relacional (Dyer y Singh, 1998), el trabajo integra mecanismos de las capacidades relacionales y capacidades competitivas en el concepto denominado ¿capacidades interorganizativas¿. Las capacidades interorganizativas se componen de la ¿confianza¿ y los mecanismos ¿combinar recursos complementarios¿, ¿invertir en activos específicos¿, ¿compartir información¿ y ¿solucionar problemas conjuntamente¿. La medición tiene lugar en la Industria Alimentaria (IA) española en un contexto de Supply Chain Management1 en red. Además de mejorar el conocimiento sobre las relaciones interorganizativas, el trabajo también realiza una revisión teórica sobre el sector agroalimentario en general y la IA en particular. Los resultados permiten confirmar, con excepciones, el constructo teórico de las ¿capacidades interorganizativas en un contexto de Supply Chain Management en red¿. Otros resultados obtenidos son los altos niveles de confianza en las relaciones entre socios y una industria que, pese al entorno competitivo y complejo actual, presenta niveles competitivos en términos de flexibilidad, respuesta, calidad y eficiencia. De igual modo, la investigación descubre la implantación de la capacidad de las empresas de la industria para gestionar el conocimiento. En este contexto, los resultados parecen indicar una correcta integración de la cadena de suministros de la IA que confirman la efectiva aplicación de la Supply Chain Management. Otras conclusiones obtenidas son la dependencia que ha tenido y tiene la industria alimentaria española de la distribución, intensificada en parte por la expansión de las marcas del distribuidor (MDDs).

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The purpose of this study was to examine the relationship between visual acuity and the two components of conceptual tempo, response accuracy and response latency. Subjects were chosen at random. Each subject was then administered a test of conceptual tempo, the Matching Familiar Figures Test (MFFT) and a test of visual acuity, the Snellen. The only significant relationship found was that between response accuracy and near visual acuity. Subjects with superior visual acuity made significantly fewer errors than did those with average or inferior acuity. It was concluded that visual acuity is an important determinant of MFFT performance. Based on these results, it was recommended that further research examine the relationship between visual acuity and other psychometric measures containing a visual component.

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One of the most significant research topics in computer vision is object detection. Most of the reported object detection results localise the detected object within a bounding box, but do not explicitly label the edge contours of the object. Since object contours provide a fundamental diagnostic of object shape, some researchers have initiated work on linear contour feature representations for object detection and localisation. However, linear contour feature-based localisation is highly dependent on the performance of linear contour detection within natural images, and this can be perturbed significantly by a cluttered background. In addition, the conventional approach to achieving rotation-invariant features is to rotate the feature receptive field to align with the local dominant orientation before computing the feature representation. Grid resampling after rotation adds extra computational cost and increases the total time consumption for computing the feature descriptor. Though it is not an expensive process if using current computers, it is appreciated that if each step of the implementation is faster to compute especially when the number of local features is increasing and the application is implemented on resource limited ”smart devices”, such as mobile phones, in real-time. Motivated by the above issues, a 2D object localisation system is proposed in this thesis that matches features of edge contour points, which is an alternative method that takes advantage of the shape information for object localisation. This is inspired by edge contour points comprising the basic components of shape contours. In addition, edge point detection is usually simpler to achieve than linear edge contour detection. Therefore, the proposed localization system could avoid the need for linear contour detection and reduce the pathological disruption from the image background. Moreover, since natural images usually comprise many more edge contour points than interest points (i.e. corner points), we also propose new methods to generate rotation-invariant local feature descriptors without pre-rotating the feature receptive field to improve the computational efficiency of the whole system. In detail, the 2D object localisation system is achieved by matching edge contour points features in a constrained search area based on the initial pose-estimate produced by a prior object detection process. The local feature descriptor obtains rotation invariance by making use of rotational symmetry of the hexagonal structure. Therefore, a set of local feature descriptors is proposed based on the hierarchically hexagonal grouping structure. Ultimately, the 2D object localisation system achieves a very promising performance based on matching the proposed features of edge contour points with the mean correct labelling rate of the edge contour points 0.8654 and the mean false labelling rate 0.0314 applied on the data from Amsterdam Library of Object Images (ALOI). Furthermore, the proposed descriptors are evaluated by comparing to the state-of-the-art descriptors and achieve competitive performances in terms of pose estimate with around half-pixel pose error.

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No mercado têm surgido alternativas aos produtos de colagem de origem animal, nomeadamente as proteínas de origem vegetal e extratos de levedura. O objectivo deste trabalho foi a comparação de um elevado número de produtos de colagem de origem animal (gelatinas) e produtos alternativos de origem vegetal e levuriano. Inicialmente os produtos de colagem foram aplicados ao vinho em diferentes doses. Com base na avaliação sensorial, foram selecionados os produtos e as doses que revelaram melhor desempenho. Os produtos de colagem selecionados foram aplicados ao vinho e avaliado o seu efeito nas características sensoriais e físico-químicas. O parâmetro que apresentou diferenças mais significativas foi a turbidez. A análise estatística apenas revelou diferenças significativas para os atributos qualidade do sabor e nota final; apesar de não evidenciar diferenças significativas, as variações observadas para o atributo extração/secura foram muito importantes do ponto de vista prático. As gelatinas que mostraram melhor desempenho foram as POA 10 e POA 12 e as proteínas vegetais POV 6 (proteína de ervilha) e POV 10 (proteína de batata). Este estudo permitiu a recolha de informação para ser utilizada na seleção do produto de colagem mais apropriado para o perfil de vinho da adega e a alternativa mais apropriada às gelatinas.

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Poucos são os estudos que relacionam variáveis de nível individual como o género, idade e antiguidade na empresa, com a percepção de contracto psicológico, no entanto para além destas variáveis moldarem o conteúdo do contracto psicológico (Guest, 2004), parecem também determinar diferentes valores e interesses de trabalho (Elizur, 1994; Bal, Lange, Jansen e Velde, 2008). Tais evidências chamam a atenção das organizações para o facto de diferentes grupos de trabalhadores apresentarem diferentes percepções de contracto psicológico, podendo consequentemente responder de diferente forma às mesmas políticas organizacionais (Freese & Schalk, 1996). O presente estudo procurou perceber se diferentes grupos de trabalhadores, de diferentes géneros, idades e antiguidades apresentam diferentes percepções de contracto psicológico, procurando posteriormente aceder às causas percebidas de quebra de contracto (Renegação, Disrupção, Incongruência e Anulação), mencionadas na literatura por Rousseau (1995) e Morrinson e Robinson (1997). Foi utilizada uma amostra, recolhida por conveniência, de 83 participantes pertencentes a uma empresa do sector alimentar, constituída por 57,8% de mulheres e 42,2% de homens. Em média possuem 37 anos de idade e 9 anos de antiguidade na empresa. Foi aplicado um questionário, desenvolvido por Lester, Turnley, Bloodgood e Bolino (2002) constituído por diferentes dimensões (Compensação, Recompensas com base na performance, Características da Função, Progressão e Desenvolvimento, Recursos e Relação Laboral) que constituem o contracto psicológico, assim como pelas diferentes causas percebidas de incumprimento da promessa. Após uma análise factorial, foram extraídos 5 factores (Características da Função, Relação Laboral, Compensação, Recursos e Progressão e Recompensas com base na performance). Os resultados demonstraram que os trabalhadores mais velhos percepcionam que a sua empresa lhes proporciona menos do que o prometido relativamente à Compensação, resultados igualmente obtidos para os trabalhadores com mais antiguidade na empresa. Uma posterior análise correlacional demonstrou que a idade está associada com a antiguidade dos trabalhadores. Quanto à causa percebida de incumprimento, os resultados evidenciaram que a maioria dos trabalhadores atribui o incumprimento das promessas à Renegação. Por outras palavras, os trabalhadores entendem que a sua organização não cumpriu as promessas que lhes fez, simplesmente porque assim o quis.

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Complete and transparent reporting of key elements of diagnostic accuracy studies for infectious diseases in cultured and wild aquatic animals benefits end-users of these tests, enabling the rational design of surveillance programs, the assessment of test results from clinical cases and comparisons of diagnostic test performance. Based on deficiencies in the Standards for Reporting of Diagnostic Accuracy (STARD) guidelines identified in a prior finfish study (Gardner et al. 2014), we adapted the Standards for Reporting of Animal Diagnostic Accuracy Studies—paratuberculosis (STRADAS-paraTB) checklist of 25 reporting items to increase their relevance to finfish, amphibians, molluscs, and crustaceans and provided examples and explanations for each item. The checklist, known as STRADAS-aquatic, was developed and refined by an expert group of 14 transdisciplinary scientists with experience in test evaluation studies using field and experimental samples, in operation of reference laboratories for aquatic animal pathogens, and in development of international aquatic animal health policy. The main changes to the STRADAS-paraTB checklist were to nomenclature related to the species, the addition of guidelines for experimental challenge studies, and the designation of some items as relevant only to experimental studies and ante-mortem tests. We believe that adoption of these guidelines will improve reporting of primary studies of test accuracy for aquatic animal diseases and facilitate assessment of their fitness-for-purpose. Given the importance of diagnostic tests to underpin the Sanitary and Phytosanitary agreement of the World Trade Organization, the principles outlined in this paper should be applied to other World Organisation for Animal Health (OIE)-relevant species.

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Agroforestry has large potential for carbon (C) sequestration while providing many economical, social, and ecological benefits via its diversified products. Airborne lidar is considered as the most accurate technology for mapping aboveground biomass (AGB) over landscape levels. However, little research in the past has been done to study AGB of agroforestry systems using airborne lidar data. Focusing on an agroforestry system in the Brazilian Amazon, this study first predicted plot-level AGB using fixed-effects regression models that assumed the regression coefficients to be constants. The model prediction errors were then analyzed from the perspectives of tree DBH (diameter at breast height)?height relationships and plot-level wood density, which suggested the need for stratifying agroforestry fields to improve plot-level AGB modeling. We separated teak plantations from other agroforestry types and predicted AGB using mixed-effects models that can incorporate the variation of AGB-height relationship across agroforestry types. We found that, at the plot scale, mixed-effects models led to better model prediction performance (based on leave-one-out cross-validation) than the fixed-effects models, with the coefficient of determination (R2) increasing from 0.38 to 0.64. At the landscape level, the difference between AGB densities from the two types of models was ~10% on average and up to ~30% at the pixel level. This study suggested the importance of stratification based on tree AGB allometry and the utility of mixed-effects models in modeling and mapping AGB of agroforestry systems.

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Dissertação (mestrado)—Universidade de Brasília, Faculdade de Economia, Administração e Contabilidade, Programa de Pós-Graduação em Administração, 2016.

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This study took place at one of the intercultural universities (IUs) of Mexico that serve primarily indigenous students. The IUs are pioneers in higher education despite their numerous challenges (Bertely, 1998; Dietz, 2008; Pineda & Landorf, 2010; Schmelkes, 2009). To overcome educational inequalities among their students (Ahuja, Berumen, Casillas, Crispín, Delgado et al., 2004; Schmelkes, 2009), the IUs have embraced performance-based assessment (PBA; Casillas & Santini, 2006). PBA allows a shared model of power and control related to learning and evaluation (Anderson, 1998). While conducting a review on PBA strategies of the IUs, the researcher did not find a PBA instrument with valid and reliable estimates. The purpose of this study was to develop a process to create a PBA instrument, an analytic general rubric, with acceptable validity and reliability estimates to assess students’ attainment of competencies in one of the IU’s majors, Intercultural Development Management. The Human Capabilities Approach (HCA) was the theoretical framework and a sequential mixed method (Creswell, 2003; Teddlie & Tashakkori, 2009) was the research design. IU participants created a rubric during two focus groups, and seven Spanish-speaking professors in Mexico and the US piloted using students’ research projects. The evidence that demonstrates the attainment of competencies at the IU is a complex set of actual, potential and/or desired performances or achievements, also conceptualized as “functional capabilities” (FCs; Walker, 2008), that can be used to develop a rubric. Results indicate that the rubric’s validity and reliability estimates reached acceptable estimates of 80% agreement, surpassing minimum requirements (Newman, Newman, & Newman, 2011). Implications for practice involve the use of PBA within a formative assessment framework, and dynamic inclusion of constituencies. Recommendations for further research include introducing this study’s instrument-development process to other IUs, conducting parallel mixed design studies exploring the intersection between HCA and assessment, and conducting a case study exploring assessment in intercultural settings. Education articulated through the HCA empowers students (Unterhalter & Brighouse, 2007; Walker, 2008). This study aimed to contribute to the quality of student learning assessment at the IUs by providing a participatory process to develop a PBA instrument.

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The aims of this thesis were to determine the animal health status in organic dairy farms in Europe and to identify drivers for improving the current situation by means of a systemic approach. Prevalences of production diseases were determined in 192 herds in Germany, France, Spain, and Sweden (Paper I), and stakeholder consultations were performed to investigate potential drivers to improve animal health on the sector level (ibid.). Interactions between farm variables were assessed through impact analysis and evaluated to identify general system behaviour and classify components according to their outgoing and incoming impacts (Paper II-III). The mean values and variances of prevalences indicate that the common rules of organic dairy farming in Europe do not result in consistently low levels of production diseases. Stakeholders deemed it necessary to improve the current status and were generally in favour of establishing thresholds for the prevalence of production diseases in organic dairy herds as well as taking actions to improve farms below that threshold. In order to close the gap between the organic principle of health and the organic farming practice, there is the need to formulate a common objective of good animal health and to install instruments to ensure and prove that the aim is followed by all dairy farmers in Europe who sell their products under the organic label. Regular monitoring and evaluation of herd health performance based on reference values are considered preconditions for identifying farms not reaching the target and thus in need of improvement. Graph-based impact analysis was shown to be a suitable method for modeling and evaluating the manifold interactions between farm factors and for identifying the most influential components on the farm level taking into account direct and indirect impacts as well as impact strengths. Variables likely to affect the system as a whole, and the prevalence of production diseases in particular, varied largely between farms despite some general tendencies. This finding reflects the diversity of farm systems and underlines the importance of applying systemic approaches in health management. Reducing the complexity of farm systems and indicating farm-specific drivers, i.e. areas in a farm, where changes will have a large impact, the presented approach has the potential to complement and enrich current advisory practice and to support farmers’ decision-making in terms of animal health.

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This thesis aims to present the ORC technology, its advantages and related problems. In particular, it provides an analysis of ORC waste heat recovery system in different and innovative scenarios, focusing on cases from the biggest to the lowest scale. Both industrial and residential ORC applications are considered. In both applications, the installation of a subcritical and recuperated ORC system is examined. Moreover, heat recovery is considered in absence of an intermediate heat transfer circuit. This solution allow to improve the recovery efficiency, but requiring safety precautions. Possible integrations of ORC systems with renewable sources are also presented and investigated to improve the non-programmable source exploitation. In particular, the offshore oil and gas sector has been selected as a promising industrial large-scale ORC application. From the design of ORC systems coupled with Gas Turbines (GTs) as topper systems, the dynamic behavior of the GT+ORC innovative combined cycles has been analyzed by developing a dynamic model of all the considered components. The dynamic behavior is caused by integration with a wind farm. The electric and thermal aspects have been examined to identify the advantages related to the waste heat recovery system installation. Moreover, an experimental test rig has been realized to test the performance of a micro-scale ORC prototype. The prototype recovers heat from a low temperature water stream, available for instance in industrial or residential waste heat. In the test bench, various sensors have been installed, an acquisitions system developed in Labview environment to completely analyze the ORC behavior. Data collected in real time and corresponding to the system dynamic behavior have been used to evaluate the system performance based on selected indexes. Moreover, various operational steady-state conditions are identified and operation maps are realized for a completely characterization of the system and to detect the optimal operating conditions.

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The first main conclusion drawn from this dissertation concerns the amount of Pt deposited on the asymmetric layer of membrane produced by tape casting porosity shaping method. Three different amounts were investigated (0.15, 1.5 and 4.5 mg cm-2 ). The most optimal performance, based on H2 permeation performances, was attained when 1.5 mg cm-2 of Pt was deposited on the porous layer, resulting in a 0.642 mL min-1 cm-2 permeated H2 when 80% H2 in He was employed as the feed. Pt deposition method is influenced by the concentration of the Pt precursor, which results in different morphology of the catalyst. The second development focused on further optimization on tape casting membranes concerning the solvent employed for the Pt catalyst deposition. The same concentration of Pt was employed, depositing 1.5 mg cm-2 on the porous side of the membrane, but a mixture of acetone and water was employed as solvent. This mixture allowed the suppression of effects leading to poorly dispersed particles. As a result, it was possible to achieve 0.74 mL min-1 cm-2 at 750°C with 50% H2 in He. Lastly, first-ever permeation performance measurements into an innovative ceramic membrane type for hydrogen separation was investigated. In-depth research was done on a group of hierarchically-structured BaCe0.65Zr0.20Y0.15O3-δ(BCZY) - Gd0.2Ce0.8O2-δ(GDC) membranes produced by freeze casting porosity shaping method. Membranes were investigated observing the effect of deposition solvent and the effect of porous layer thickness. Employing a mixture of Acetone and water resulted in better hydrogen permeation at temperatures (T > 650°C), reaching 0.26 mL min-1 cm-2 at 750°C with 50% H2 in He. The reduction of porous layer thickness led to a hydrogen flow of 0.33 mL min-1 cm-2 , at 750°C with 50% H2 in He.

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A global italian pharmaceutical company has to provide two work environments that favor different needs. The environments will allow to develop solutions in a controlled, secure and at the same time in an independent manner on a state-of-the-art enterprise cloud platform. The need of developing two different environments is dictated by the needs of the working units. Indeed, the first environment is designed to facilitate the creation of application related to genomics, therefore, designed more for data-scientists. This environment is capable of consuming, producing, retrieving and incorporating data, furthermore, will support the most used programming languages for genomic applications (e.g., Python, R). The proposal was to obtain a pool of ready-togo Virtual Machines with different architectures to provide best performance based on the job that needs to be carried out. The second environment has more of a traditional trait, to obtain, via ETL (Extract-Transform-Load) process, a global datamodel, resembling a classical relational structure. It will provide major BI operations (e.g., analytics, performance measure, reports, etc.) that can be leveraged both for application analysis or for internal usage. Since, both architectures will maintain large amounts of data regarding not only pharmaceutical informations but also internal company informations, it would be possible to digest the data by reporting/ analytics tools and also apply data-mining, machine learning technologies to exploit intrinsic informations. The thesis work will introduce, proposals, implementations, descriptions of used technologies/platforms and future works of the above discussed environments.

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Machine learning provides tools for automated construction of predictive models in data intensive areas of engineering and science. The family of regularized kernel methods have in the recent years become one of the mainstream approaches to machine learning, due to a number of advantages the methods share. The approach provides theoretically well-founded solutions to the problems of under- and overfitting, allows learning from structured data, and has been empirically demonstrated to yield high predictive performance on a wide range of application domains. Historically, the problems of classification and regression have gained the majority of attention in the field. In this thesis we focus on another type of learning problem, that of learning to rank. In learning to rank, the aim is from a set of past observations to learn a ranking function that can order new objects according to how well they match some underlying criterion of goodness. As an important special case of the setting, we can recover the bipartite ranking problem, corresponding to maximizing the area under the ROC curve (AUC) in binary classification. Ranking applications appear in a large variety of settings, examples encountered in this thesis include document retrieval in web search, recommender systems, information extraction and automated parsing of natural language. We consider the pairwise approach to learning to rank, where ranking models are learned by minimizing the expected probability of ranking any two randomly drawn test examples incorrectly. The development of computationally efficient kernel methods, based on this approach, has in the past proven to be challenging. Moreover, it is not clear what techniques for estimating the predictive performance of learned models are the most reliable in the ranking setting, and how the techniques can be implemented efficiently. The contributions of this thesis are as follows. First, we develop RankRLS, a computationally efficient kernel method for learning to rank, that is based on minimizing a regularized pairwise least-squares loss. In addition to training methods, we introduce a variety of algorithms for tasks such as model selection, multi-output learning, and cross-validation, based on computational shortcuts from matrix algebra. Second, we improve the fastest known training method for the linear version of the RankSVM algorithm, which is one of the most well established methods for learning to rank. Third, we study the combination of the empirical kernel map and reduced set approximation, which allows the large-scale training of kernel machines using linear solvers, and propose computationally efficient solutions to cross-validation when using the approach. Next, we explore the problem of reliable cross-validation when using AUC as a performance criterion, through an extensive simulation study. We demonstrate that the proposed leave-pair-out cross-validation approach leads to more reliable performance estimation than commonly used alternative approaches. Finally, we present a case study on applying machine learning to information extraction from biomedical literature, which combines several of the approaches considered in the thesis. The thesis is divided into two parts. Part I provides the background for the research work and summarizes the most central results, Part II consists of the five original research articles that are the main contribution of this thesis.

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This thesis investigated the contemporary phenomenon of detail engineering outsourcing. The case organization had pursued a new outsourcing approach with a trusted partner. The goal of this empirical study was to examine the impact of the consequential partnership outsourcing arrangement. Particularly, the beneficence of the arrangement was evaluated based on the underlying organizational routine and the long-term economic implications of its performance outcome. The case study was needed, as the unit will likely have to rely on such distance outsourcing arrangements more and more in the future, and understanding on the impact of such operations is needed. The main findings revealed that the new outsourcing arrangement is not currently a very attractive strategic option for organizing production. The benefits which stem from the emerged, unique engineering project routine are not significant enough to make the arrangement an advantageous one, especially since increasing partnering costs are being met. This conclusion was drawn via the extended transaction cost view. Benchmarking was done in reliance to an old arrangement from which the new pursuit was a departure from. The case study then enlightened the engineering unit on the impact of its strategic maneuver by combining the routines-theory framework with contemporary methods of governance structure evaluation. Through this, it was shown that greater efforts are needed to make the new outsourcing approach a more beneficial one. However, the studied arrangement was seen to inhold potential for better results. The findings can be used to capitalize on this.