821 resultados para Leadership Theories


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[EN]The present research work, based on some of the components of the Common Assessment Framework, sets to analyse the influence held by leadership in specific factors that constitute the organisational climate, and also the impact that these factors have on the quality of municipal public services. For the purposes of this study, we propose Likert’s exploitative autocratic and participative leadership styles to explain the genesis, structure and workflow. As far as the organisational climate is concerned, the variables used are motivation, satisfaction, empowerment, conflict and stress. The main conclusions that arose was that a participative leader confers higher relevance to the quality of service, through motivation, satisfaction, empowerment and human resources positive results, than an exploitative autocratic leader. Performed contributions are based on the empiric research hereby presented, and new research guidelines are proposed. The research methodology used was qualitative, based on the case study.

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Last year, Jisc began work with EDUCAUSE - the US organisation for IT professionals in higher education - to find out the skillset of the CIO of the future. One of the findings of our project was that many aspiring technology leaders find it difficult to make the step up. Louisa Dale, director Jisc group sector intelligence, talks through the learnings and opens a call for IT professionals to get involved in the next phase of work.

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Adiabatic shear localization is a mode of failure that occurs in dynamic loading. It is characterized by thermal softening occurring over a very narrow region of a material and is usually a precursor to ductile fracture and catastrophic failure. This reference source is the first detailed study of the mechanics and modes of adiabatic shear localization in solids, and provides a systematic description of a number of aspects of adiabatic shear banding. The inclusion of the appendices which provide a quick reference section and a comprehensive collection of thermomechanical data allows rapid access and understanding of the subject and its phenomena. The concepts and techniques described in this work can usefully be applied to solve a multitude of problems encountered by those investigating fracture and damage in materials, impact dynamics, metal working and other areas. This reference book has come about in response to the pressing demand of mechanical and metallurgical engineers for a high quality summary of the knowledge gained over the last twenty years. While fulfilling this requirement, the book is also of great interest to academics and researchers into materials performance.

Table of Contents

1Introduction1
1.1What is an Adiabatic Shear Band?1
1.2The Importance of Adiabatic Shear Bands6
1.3Where Adiabatic Shear Bands Occur10
1.4Historical Aspects of Shear Bands11
1.5Adiabatic Shear Bands and Fracture Maps14
1.6Scope of the Book20
2Characteristic Aspects of Adiabatic Shear Bands24
2.1General Features24
2.2Deformed Bands27
2.3Transformed Bands28
2.4Variables Relevant to Adiabatic Shear Banding35
2.5Adiabatic Shear Bands in Non-Metals44
3Fracture and Damage Related to Adiabatic Shear Bands54
3.1Adiabatic Shear Band Induced Fracture54
3.2Microscopic Damage in Adiabatic Shear Bands57
3.3Metallurgical Implications69
3.4Effects of Stress State73
4Testing Methods76
4.1General Requirements and Remarks76
4.2Dynamic Torsion Tests80
4.3Dynamic Compression Tests91
4.4Contained Cylinder Tests95
4.5Transient Measurements98
5Constitutive Equations104
5.1Effect of Strain Rate on Stress-Strain Behaviour104
5.2Strain-Rate History Effects110
5.3Effect of Temperature on Stress-Strain Behaviour114
5.4Constitutive Equations for Non-Metals124
6Occurrence of Adiabatic Shear Bands125
6.1Empirical Criteria125
6.2One-Dimensional Equations and Linear Instability Analysis134
6.3Localization Analysis140
6.4Experimental Verification146
7Formation and Evolution of Shear Bands155
7.1Post-Instability Phenomena156
7.2Scaling and Approximations162
7.3Wave Trapping and Viscous Dissipation167
7.4The Intermediate Stage and the Formation of Adiabatic Shear Bands171
7.5Late Stage Behaviour and Post-Mortem Morphology179
7.6Adiabatic Shear Bands in Multi-Dimensional Stress States187
8Numerical Studies of Adiabatic Shear Bands194
8.1Objects, Problems and Techniques Involved in Numerical Simulations194
8.2One-Dimensional Simulation of Adiabatic Shear Banding199
8.3Simulation with Adaptive Finite Element Methods213
8.4Adiabatic Shear Bands in the Plane Strain Stress State218
9Selected Topics in Impact Dynamics229
9.1Planar Impact230
9.2Fragmentation237
9.3Penetration244
9.4Erosion255
9.5Ignition of Explosives261
9.6Explosive Welding268
10Selected Topics in Metalworking273
10.1Classification of Processes273
10.2Upsetting276
10.3Metalcutting286
10.4Blanking293
 Appendices297
AQuick Reference298
BSpecific Heat and Thermal Conductivity301
CThermal Softening and Related Temperature Dependence312
DMaterials Showing Adiabatic Shear Bands335
ESpecification of Selected Materials Showing Adiabatic Shear Bands341
FConversion Factors357
 References358
 Author Index369
 Subject Index375

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Since the discovery of D-branes as non-perturbative, dynamic objects in string theory, various configurations of branes in type IIA/B string theory and M-theory have been considered to study their low-energy dynamics described by supersymmetric quantum field theories.

One example of such a construction is based on the description of Seiberg-Witten curves of four-dimensional N = 2 supersymmetric gauge theories as branes in type IIA string theory and M-theory. This enables us to study the gauge theories in strongly-coupled regimes. Spectral networks are another tool for utilizing branes to study non-perturbative regimes of two- and four-dimensional supersymmetric theories. Using spectral networks of a Seiberg-Witten theory we can find its BPS spectrum, which is protected from quantum corrections by supersymmetry, and also the BPS spectrum of a related two-dimensional N = (2,2) theory whose (twisted) superpotential is determined by the Seiberg-Witten curve. When we don’t know the perturbative description of such a theory, its spectrum obtained via spectral networks is a useful piece of information. In this thesis we illustrate these ideas with examples of the use of Seiberg-Witten curves and spectral networks to understand various two- and four-dimensional supersymmetric theories.

First, we examine how the geometry of a Seiberg-Witten curve serves as a useful tool for identifying various limits of the parameters of the Seiberg-Witten theory, including Argyres-Seiberg duality and Argyres-Douglas fixed points. Next, we consider the low-energy limit of a two-dimensional N = (2, 2) supersymmetric theory from an M-theory brane configuration whose (twisted) superpotential is determined by the geometry of the branes. We show that, when the two-dimensional theory flows to its infra-red fixed point, particular cases realize Kazama-Suzuki coset models. We also study the BPS spectrum of an Argyres-Douglas type superconformal field theory on the Coulomb branch by using its spectral networks. We provide strong evidence of the equivalence of superconformal field theories from different string-theoretic constructions by comparing their BPS spectra.

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In the quest for a descriptive theory of decision-making, the rational actor model in economics imposes rather unrealistic expectations and abilities on human decision makers. The further we move from idealized scenarios, such as perfectly competitive markets, and ambitiously extend the reach of the theory to describe everyday decision making situations, the less sense these assumptions make. Behavioural economics has instead proposed models based on assumptions that are more psychologically realistic, with the aim of gaining more precision and descriptive power. Increased psychological realism, however, comes at the cost of a greater number of parameters and model complexity. Now there are a plethora of models, based on different assumptions, applicable in differing contextual settings, and selecting the right model to use tends to be an ad-hoc process. In this thesis, we develop optimal experimental design methods and evaluate different behavioral theories against evidence from lab and field experiments.

We look at evidence from controlled laboratory experiments. Subjects are presented with choices between monetary gambles or lotteries. Different decision-making theories evaluate the choices differently and would make distinct predictions about the subjects' choices. Theories whose predictions are inconsistent with the actual choices can be systematically eliminated. Behavioural theories can have multiple parameters requiring complex experimental designs with a very large number of possible choice tests. This imposes computational and economic constraints on using classical experimental design methods. We develop a methodology of adaptive tests: Bayesian Rapid Optimal Adaptive Designs (BROAD) that sequentially chooses the "most informative" test at each stage, and based on the response updates its posterior beliefs over the theories, which informs the next most informative test to run. BROAD utilizes the Equivalent Class Edge Cutting (EC2) criteria to select tests. We prove that the EC2 criteria is adaptively submodular, which allows us to prove theoretical guarantees against the Bayes-optimal testing sequence even in the presence of noisy responses. In simulated ground-truth experiments, we find that the EC2 criteria recovers the true hypotheses with significantly fewer tests than more widely used criteria such as Information Gain and Generalized Binary Search. We show, theoretically as well as experimentally, that surprisingly these popular criteria can perform poorly in the presence of noise, or subject errors. Furthermore, we use the adaptive submodular property of EC2 to implement an accelerated greedy version of BROAD which leads to orders of magnitude speedup over other methods.

We use BROAD to perform two experiments. First, we compare the main classes of theories for decision-making under risk, namely: expected value, prospect theory, constant relative risk aversion (CRRA) and moments models. Subjects are given an initial endowment, and sequentially presented choices between two lotteries, with the possibility of losses. The lotteries are selected using BROAD, and 57 subjects from Caltech and UCLA are incentivized by randomly realizing one of the lotteries chosen. Aggregate posterior probabilities over the theories show limited evidence in favour of CRRA and moments' models. Classifying the subjects into types showed that most subjects are described by prospect theory, followed by expected value. Adaptive experimental design raises the possibility that subjects could engage in strategic manipulation, i.e. subjects could mask their true preferences and choose differently in order to obtain more favourable tests in later rounds thereby increasing their payoffs. We pay close attention to this problem; strategic manipulation is ruled out since it is infeasible in practice, and also since we do not find any signatures of it in our data.

In the second experiment, we compare the main theories of time preference: exponential discounting, hyperbolic discounting, "present bias" models: quasi-hyperbolic (α, β) discounting and fixed cost discounting, and generalized-hyperbolic discounting. 40 subjects from UCLA were given choices between 2 options: a smaller but more immediate payoff versus a larger but later payoff. We found very limited evidence for present bias models and hyperbolic discounting, and most subjects were classified as generalized hyperbolic discounting types, followed by exponential discounting.

In these models the passage of time is linear. We instead consider a psychological model where the perception of time is subjective. We prove that when the biological (subjective) time is positively dependent, it gives rise to hyperbolic discounting and temporal choice inconsistency.

We also test the predictions of behavioral theories in the "wild". We pay attention to prospect theory, which emerged as the dominant theory in our lab experiments of risky choice. Loss aversion and reference dependence predicts that consumers will behave in a uniquely distinct way than the standard rational model predicts. Specifically, loss aversion predicts that when an item is being offered at a discount, the demand for it will be greater than that explained by its price elasticity. Even more importantly, when the item is no longer discounted, demand for its close substitute would increase excessively. We tested this prediction using a discrete choice model with loss-averse utility function on data from a large eCommerce retailer. Not only did we identify loss aversion, but we also found that the effect decreased with consumers' experience. We outline the policy implications that consumer loss aversion entails, and strategies for competitive pricing.

In future work, BROAD can be widely applicable for testing different behavioural models, e.g. in social preference and game theory, and in different contextual settings. Additional measurements beyond choice data, including biological measurements such as skin conductance, can be used to more rapidly eliminate hypothesis and speed up model comparison. Discrete choice models also provide a framework for testing behavioural models with field data, and encourage combined lab-field experiments.

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This project will examine cultural differences and dimensions and how they affect negotiations and intercultural management. It is necessary to consider that the cultural characteristics of each society, which in turn is made of different individuals, make intercultural relations complex and with many subtleties. We will apply these proposals to draw a comparison between Spain and two Southeast Asian countries: India and Sri Lanka using Hofstede’s cultural dimensions.This project will examine cultural differences and dimensions and how they affect negotiations and intercultural management. It is necessary to consider that the cultural characteristics of each society, which in turn is made of different individuals, make intercultural relations complex and with many subtleties. We will apply these proposals to draw a comparison between Spain and two Southeast Asian countries: India and Sri Lanka using Hofstede’s cultural dimensions.

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The general superresolution theories for uniform amplitude beams and intercepted Gaussian beams are investigated. For these two types of incident beam, both two-zone amplitude and pure-phase filters are adopted to provide specific numerical descriptions of their differences in superresolution performances. Simulated results of comparisons between their performances indicate that, with the same spot size ratio, the intercepted Gaussian beam achieves a higher central image brightness ratio and significantly lower side-lobe effect irrespective of the filter used. (c) 2008 Elsevier Ltd. All rights reserved.

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[EN] The main goal of this study is to analyze how organizational commitment has a mediating effect on the relation between transformational leadership and organizational trust. Therefore we developed an organization analysis based on a survey that was used to collect primary data from a sample of 58 employees. We obtained a 71% response rate and these data were analyzed using quantitative methodological techniques and linear regression. The research was conducted at the Serralves Foundation (Porto, Portugal) to empirically test the proposed research model and its hypotheses. The empirical results confirm that transformational leadership positively enhances organizational trust. However, transformational leadership and organizational trust are not significantly influenced by organizational commitment, thus not having a mediating effect on this relationship. Such results assume particular relevance because they become a basis for comparative studies in similar organizations. This study brings some theoretical contributions to the literature by analyzing the mediating effect of organizational commitment on the relation between transformational leadership and organizational trust in cultural organizations and has also some practical management implications, as it draws attention to the importance of a set of practices, job satisfaction oriented, which can effectively lead to organizational commitment intervention in the relationship between transformational leadership and organizational trust.

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Throughout this undergraduate thesis, a study of intercultural management and leadership will be carried out with a special focus on language academies. We begin by analyzing the importance of cultural values and their effects on the perception of a leader. We then study the role of Strategic Human Resources Management in an intercultural environment. Finally, as an original contribution to this thesis, an investigation is performed that examines three local language academies and their management practices. After reviewing the findings, we hope to propose a sort of ‘best practices’ for language academies that could lead to a more harmonious relationship between teachers and their managers.

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El presente trabajo trata de analizar y explicar la relación entre el comportamiento de los individuos en las empresas y la consecución de los objetivos establecidos a través de la aplicación práctica de diferentes teorías de liderazgo y motivación en una empresa real como es Iberdrola. Debido a las dimensiones de la empresa y a la complejidad a la hora de obtener información relevante para el proyecto, centraremos nuestro análisis únicamente en el departamento de Compras y Seguros. Consideramos que las personas son el activo más valioso de las empresas ya que, al fin y al cabo, son el único factor diferenciador de las empresas, es el factor que puede distinguir entre una compañía competitiva de otra que no lo es. Por ello, creemos que es imprescindible analizar el comportamiento de los componentes de una empresa para identificar posibilidades de mejora, con el fin de alcanzar los objetivos establecidos. El proyecto tal y como hemos mencionado, principalmente se centra en el análisis del liderazgo y la motivación existente en el equipo de Compras y Seguros de Iberdrola S.A. Con los resultados obtenidos en el análisis se realizará una propuesta de valor con el fin de aportar diferentes alternativas que, acorde con algunas teorías organizacionales, puedan beneficiar a la empresa a la hora de conseguir sus diferentes metas en función de la situación en la que esté la empresa, las cualidades y comportamientos de todos sus componentes.