Submitted by (ana.araujo@ufrpe.br) on 2016-08-03T15:37:53Z No. of bitstreams: 1 Luiz Medeiros de Araujo Lima Filho.pdf: 6714156 bytes, checksum: 8537b197237b8261b5b264ad769ab466 (MD5) / Made available in DSpace on 2016-08-03T15:37:53Z (GMT). No. of bitstreams: 1 Luiz Medeiros de Araujo Lima Filho.pdf: 6714156 bytes, checksum: 8537b197237b8261b5b264ad769ab466 (MD5) Previous issue date: 2012-10-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Knowledge of growth and production present and future of trees in forest stands is a key element in sustainable forest management. It is intended in this thesis to estimate the frequency distribution by diameter class, estimate and compare volumetric equations via symmetric nonlinear models as well, propose to compare models and adjust volume growth via symmetrical nonlinear models in Eucalyptus spp. clones in the region of the Araripe - PE. The experiment was conducted at the Experimental Station of the Agricultural Research Company of Pernambuco (IPA), located in the municipality of Araripina - PE. This experiment consists of 15 clones of Eucalyptus spp., species and hybrids resulting from natural crossing and controlled pollination. The database is composed of all the survival trees of the experiment, corresponding to 1189 trees, divided into three groups. To estimate the diameter distributions were adopted probability distributions Normal, with three parameters Weibull, Log-normal and Gamma. The next step was to fit of the model of Schumacher and Hall and Spurr model associated the following symmetric distributions: Normal, Student t, Exponential Power and Logistics II. The volume growth models in this thesis were adjusted with symmetric distributions associated with them. In the estimation of the diameter distributions, the results were similar in the three groups, with emphasis on the Log-normal distribution. This distribution was the most appropriate for most of the period. Analyzing the volumetric equations, it was found that the model was Schumacher and Hall the most suitable, when associated with the Student t distribution with three degrees .of freedom and Exponential Power (t = 0,8) respectively to groups I and II. In group III, the model Spurr associated with Exponential Power (t = 0,8) distribution had the best performance. Comparing the volume growth models, it was observed that the proposed models best fits obtained in this thesis, when the distributions associated with the Student t with three degrees of freedom and Exponential Power (t = 0,8), respectively, in groups I and III. In group II, the Chapman-Richards model associated with Student t distribution with three degrees of freedom had the best performance. / O conhecimento do crescimento e da produção presente e futura de árvores em povoamentos florestais é elemento fundamental no manejo florestal sustentável. Desta forma, pretende-se nesta tese estimar a distribuição de frequência por classe diamétrica, estimar e comparar equações volumétricas via modelos simétricos não lineares, bem como, propor, ajustar e comparar modelos de crescimento em volume via modelos simétricos não lineares em clones de Eucalyptus spp. na região da Chapada do Araripe - PE. O experimento foi desenvolvido na Estação Experimental da Empresa Pernambucana de Pesquisa Agropecuária (IPA), localizada no município de Araripina - PE. Esse experimento é composto por 15 clones de Eucalyptus spp., resultantes de espécies e híbridos de cruzamento natural e polinização controlada. A base de dados foi composta por todas as árvores sobreviventes do experimento, que corresponde a 1189 árvores, dividida em três grupos. Para estimar as distribuições diamétricas foram adotadas as distribuições de probabilidade Normal, Weibull com três parâmetros, Log-normal e Gama. Em seguida, procedeu-se com os ajustes dos modelos volumétricos de Schumacher e Hall e de Spurr associados as seguintes distribuições simétricos: Normal, t de Student, Exponencial Potência e Logística II. Posteriormente, os modelos de crescimento em volume propostos nesta tese foram ajustados associados às mesmas distribuições simétricas. Na estimativa das distribuições diamétricas, os resultados foram similares nos três grupos, com destaque para a distribuição Log-normal. Essa distribuição foi a mais significativa na maior parte do período avaliado. Analisando as equações volumétricas, observou-se que o modelo de Schumacher e Hall obteve o melhor desempenho, quando associado as distribuições t de Student com três graus de liberdade e Exponencial Potência (t = 0,8), respectivamente, para os grupos I e II. No grupo III, o modelo de Spurr associado a distribuição Exponencial Potência (t = 0,8) obteve o melhor desempenho. Comparando os modelos de crescimento em volume, observou-se que os modelos propostos nesta tese obtiveram melhores ajustes, quando associados as distribuições t de Student com três graus de liberdade e Exponencial Potência (t = 0,8), respectivamente, nos grupos I e III. No grupo II, o modelo de Chapman-Richards associado a distribuição t de Student com três graus de liberdade obteve o melhor desempenho.

Bakgrund: Medarbetares engagemang är oroväckande lågt såväl nationellt som internationellt vilket är ett kostsamt problem för organisationer då detta kan bidra till lägre produktivitet, försämrad kundnöjdhet och minskad lojalitet hos de anställda. Ett viktigt verktyg som organisationer kan använda sig av för att stärka medarbetares engagemang är att skapa en väl fungerande intern kommunikation. Denna kommunikation har ur ett organisatoriskt perspektiv fått en mer framträdande roll då den interna informationen mellan ledning och medarbetare måste anpassas utifrån medarbetares behov för att på så sätt ge det bästa förutsättningarna för att nå organisatorisk framgång och bidra till ett högre engagemang. Syfte: Syftet med denna uppsats har varit att få en ökad förståelse över hur organisationers symmetriska interna kommunikation påverkar anställdas engagemang, sett ur en medarbetares perspektiv. Metod: Studiens syfte har varit att få en ökad förståelse för det valda problemområdet vilket resulterat i att en kvalitativ forskningsansats använts. För att undersöka engagemang hos de anställda genomfördes nio stycken semistrukturerade intervjuer. Denna metod användes för att fånga informanternas subjektiva upplevelser om engagemang kopplat till symmetrisk intern kommunikation. De nio informanterna valdes ut från en organisation, där urvalet gjordes strategiskt slumpmässigt. Organisationen valdes då de aktivt arbetade med symmetrisk intern kommunikation och medarbetarnas engagemang. Resultat/Slutsats: Denna studie har kommit fram till att det är kombinationen av symmetrisk och asymmetrisk kommunikation som skapar det gynnsammaste förutsättningarna för en väl fungerande intern kommunikation. Kombinationen av interna kommunikationskanaler underlättar de anställdas arbetssituation och bidrar till ett ökat engagemang. / Background: Employee commitment is worryingly low, both nationally and internationally which is a costly problem for organizations as this may contribute to lower productivity, reduced customer satisfaction and reduced employee loyalty. An important tool that organizations can use to strengthen the employees' commitment is to create a well-functioning internal communication. This communication has from an organizational perspective been given a more prominent role since internal information between management and employees must be adjusted on the basis of employees' needs so as to provide the best conditions for achieving organizational success and contribute to a higher commitment. Purpose: The purpose of this study was to obtain a better understanding of how organizations symmetrical internal communication affects employee engagement, seen from an employee's perspective. Method: The study's purpose was to get a better understanding of the chosen problem area which resulted that a qualitative research approach was used. To investigate the corporate commitment of the employee’s nine semi-structured interviews was conducted. This method was used to capture the informants' subjective experiences of commitment linked to symmetrical internal communication. The nine informants were selected from one organization, where the selection was made strategically random. The organization was chosen as it actively worked with symmetric internal communications and employees’ commitment. Results/Conclusion: This study has come to the conclusion that it is the combination of symmetrical communication and asymmetric communication that creates the most favorable conditions for well-functioning internal communication. The combination of internal communication channels facilitates the employees' work situation and contributes to increased engagement.

Les structures treillis constituées d’un nombre important de barres sont largement utilisées, notamment en génie civil. L’étude par éléments finis de telles structures se révèle très coûteuse dès que la maille répétitive du treillis est complexe. Il s’avère intéressant de réduire la taille du problème en définissant un milieu continu équivalent. L’objectif de la première partie de ce travail est de proposer, en se plaçant dans le cadre des méthodes d’homogénéisation des milieux périodiques, une poutre de Timoshenko équivalente à une structure périodique dont l’une des dimension est grande par rapport aux deux autres. Une des originalités réside dans l’étude de cellules de base non symétriques. Par ailleurs, on s’intéresse à la prise en compte de déformations libres (par exemple, d’origine thermique) apparaissant à l’échelle microscopique. La seconde partie est consacrée à l’étude de la structure axonémale du flagelle et des cils vibratiles. Il s’agit de proposer et valider un modèle pour cette structure biomécanique complexe et d’appliquer ensuite la méthode d’homogénéisation proposée / Lattice structures are widely used, especially in civil engineering. The finite element analysis of such structures might require a consequent amount of computational time when the periodical mesh of this lattice is complex. Defining an equivalent continuous medium in order to reduce the size of the problem appears to be interesting. The aim of the first part of this document is to apply a homogenization method in order to find a Timoshenko beam model macroscopically equivalent to a slender structure which is periodical in the longitudinal direction. One of the unusual aspects tackled reside in the study of structures with periodical cells having a longitudinal asymmetry. In addition, the case of periodical structures with free deformation (e.g. thermal dilatation) at microscopic scale is dealt. The second part is consecrated to the study of the axonemal structure of the biological cell flagella and Cilia. A shorten version of the axonemal structure is studied at first and homogenized afterward

The thesis deals with analyses of the laboratory symmetrical supplies with adjustable output voltage. It also describes different kinds of current cut-out circuits and several most frequent supply connection schemes. Analyses (simulation program OrCAD) show the characteristics and behaviour of the mentioned supplies. To set the output voltage, operational amplifier structures or linear three-terminal voltage regulator are very often used. The suggested supply was tested and its parameters compared with the simulations. The value of output voltage and current can be controlled with a computer with a USB port. For controlling of the output voltage and current the digital potentiometers were used and controlled by I2C bus.

This thesis presents the main results of a five-month ethnographic research project in a global factory in the Czech Republic. It is focused on three topics. Due to a number of ethical dilemmas that accompanied the research, the first part examines ethics in anthropology, both the instruments of the institutionalization of professional ethics and "ethics in practice". As a strategy for dealing with ethical dilemmas the thesis aims at a reflexive approach, as proposed by Guillemin and Gillam (2004) not only to ensure rigor in research methodology, but also as a form of "morally adequate research work". The second research focus is the production line. The line makes sense - that is, produces stuff - only when people and machines interconnect. Symmetrical analysis juxtaposes humans and machines and explores the dynamics of agency as it shifts the borders between people and machines and the characteristics that each takes from the other. The last part of the thesis presents the factory as an actor in the labor market. Through the analysis of economic and organizational factors as well as workers" stories and interpretations and regional authorities" accounts, the final part tries to explain the perception of the factory as a stable and relatively solid employer. Keywords: global factory, ethics,...

Twitter has become a foremost public relations tool due to its capacity to facilitate two-way communication; however research suggests few organizations are using it effectively to engage in conversation with their customers (Rybalko & Seltzer, 2010; Briones, Kuch, Liu, & Jin, 2011; Lovejoy, Waters, & Saxon, 2012; Waters & Jamal, 2011). Using Grunig and Hunt's (1984) models of public relations and uses and gratifications theory (Katz, Blumler, & Gurevitch, 1974) as the guiding framework, this study examines how teams in the National Hockey League (NHL) communicate with fans on Twitter. The study used a content analysis and coded 815 team tweets into one of five content themes based on the fan gratification being met. Findings revealed that teams are most likely to meet fans' information needs and use models of press agentry and public information, despite the opportunity for conversation and relationship building Twitter provides. The results indicate there is a lack of two-way conversation being facilitated by NHL teams to build relationships with fans. The results of this study will inform sports teams, as well as other organizations, on current and future communication strategies on social media.

More research is needed to be able to fully understand the role that social media plays in elections, specifically in local elections. Candidates need to understand how it works and how they can effectively use this new communication medium. By exploring Diffusion of Innovation Theory, Social Information Processing Theory, and the Two-Way Symmetrical Model of communications this study sought to answer one overarching question: how should a candidate employ social media in a local election? This qualitative, single case study explores the 2014 recall and general election in Yorba Linda, California. Councilman Tom Lindsey and candidate Matt Palmer are the primary subjects of study. Observations were made through analysis of documentation, interviews, and participant and direct observation. The researcher was employed as the campaign manager for both Lindsey's and Palmer's campaigns. The findings support the use of social media in local campaigns on a case by case basis. Determining use depends on the demographics of the voters and the abilities of the candidate. The data suggests that social media needs to be part of comprehensive strategy that includes traditional communication tools. Observations from the case study illustrate the need for candidates to engage in two-way communication that is monitored and regulated. This study begins to establish social media as a tool that candidates can use to inexpensively reach voters in a way that showcases the candidate's personality and allows them to connect on a personal level with constituents. Social media will play a role in politics at all levels.

Modeling articulated objects made of rigid layered parts used to populate 3D scenes in video games or movie production is a complex and time-consuming task for digital artists. This work proposes a sketch-based approach to efficiently model 3D layered articulated objects, such as animals with rigid shells and armors, in annotating a single 2D photo manually, and eventually fabricate it from automatically computed 2D patterns. In considering symmetrical objects seen under a 3/4 view, and an- notating salient features such as extremities of the rigid articulated parts as a mix of circular and Bézier curve, this approach is able to retrieve depth information, hidden parts, and rotation-articulated structure. The resulting shape consists of a set of quadrangulated polygons that may be flattened in 2D. Details such as ears, tails, and legs were further models using dedicated annotations. The accuracy of the reconstruction has been validated on synthetic cylindrical examples, and its ro- bustness in reconstructing a 3D model of armor, armadillo, and shrimp. The latter was finally fabricated using paper. / Att modellera artikulerade objekt gjorda av styva delar lagda i lager som används till att fylla 3D-scener i datorspel och filmskapande är en komplex och tidsödande uppgift för digitala konstnärer. Den här undersökningen föreslår ett skiss-baserat tillvägagångssätt att effektivt modellera artikulerade 3D-objekt lagda i lager, såsom djur med styva skal och rustning, i att annotera ett 2D-foto manuellt, och eventuellt skapa det från automatiskt beräknade 2D-mönster. Hänsyn är tagen till symmetriska objekt sedda under en 3/4 vy, och annotera framträdande egenskapersåsom extremiteter av de styva artikulerade delarna som en blandning avcirkulära och Bézier-kurvor, kan det här tillvägagångssättet hämta information om djup, gömda delar och rotations-artikulerade strukturer. Den slutliga formen består av ett set av fyrsidiga polygoner som kan bli tillplattade i 2D. Detaljer såsom öron, svansar och ben där framtida modeller använder dedikerade annotationer. Noggrannheten av rekonstruktionen har blivit validerad på syntetiska cylindriska exempeloch dess robusthet i att rekonstruera en 3D-modell av en rustning, ett bältdjur och en räka. Den senare skapades slutligen med hjälp av papper.

Virtual Reality (VR) is valuable for educational purposes, particularly procedural learning. However, single-user applications lack the benefits of teacher guidance. Symmetrical VR systems, where both teacher and student use VR, have limitations in supervision and accessing external materials. Asymmetrical systems can solve this problem by allowing the teacher to use a different device. To investigate the potential of an asymmetrical VR system and the impact of embodiment on the learning experience, an asymmetrical VR system was developed using a tablet. The system was tested using an assembly task to explore the impact of embodiment (no avatar, avatar without hands, avatar with hands) and the teacher’s device, VR Head-Mounted Display (HMD) or tablet, on task difficulty, performance, social presence, communication quality, and preference. Results indicated that an avatar with hands yielded the best outcomes, and communication was similar to face-to-face interaction. The experience of the asymmetrical system, in which only the student used a VR HMD, was perceived alike compared to a similar symmetrical system, in which both student and teacher used a VR HMD. Therefore, an asymmetrical VR system can be a feasible option for Collaborative Virtual Environments, offering cost-effectiveness and easier set-up while not isolating the teacher from the physical environment. / Virtual Reality (VR) är värdefullt för utbildningsändamål, särskilt inom procedurellt lärande. Applikationer för enskilda användare saknar dock fördelarna med lärarhandledning. Symmetriska VR-system, där både lärare och student använder VR, har begränsningar när det gäller bevakning och tillgång till externa material. Asymmetriska system kan lösa detta problem genom att låta läraren använda en annan enhet. För att undersöka potentialen hos ett asymmetriskt VR-system och förkroppsligandets inverkan på lärandeupplevelsen utvecklades ett asymmetriskt VR-system med hjälp av en surfplatta. Systemet testades med en montageuppgift för att utforska hur förkroppsligandet (ingen avatar, avatar utan händer, avatar med händer) och lärarens enhet, VR Head-Mounted Display (HMD) eller surfplatta, påverkar uppgiftens svårighetsgrad, prestation, social närvaro, kommunikationskvalitet och preferenser. Resultaten visade att en avatar med händer gav bäst resultat och att kommunikationen var liknande ansikte mot ansikte-interaktion. Upplevelsen av det asymmetriska systemet, där bara studenten använde en VR HMD, uppfattades snarlik ett liknande symmetriskt system, där både studenten och läraren använde en VR HMD. Därför kan ett asymmetriskt VR-system vara ett användbart alternativ för virtuella miljöer för samarbete, eftersom det är kostnadseffektivt och enklare att installera samtidigt som det inte isolerar läraren från den fysiska miljön.

This paper describes the design, fabrication, and testing of a 1.2 kV, 6.5 mΩ, half-bridge, SiC MOSFET power module to evaluate the impact of parametric device tolerances on electrical and thermal performance. Paralleling power devices increases current handling capability for the same bus voltage. However, inherent parametric differences among dies leads to unbalanced current sharing causing overstress and overheating. In this design, a symmetrical DBC layout is utilized to balance parasitic inductances in the current pathways of paralleled dies to isolate the impact of parametric tolerances. In addition, the paper investigates the benefits of flexible PCB in place of wire bonds for the gate loop interconnection to reduce and minimize the gate loop inductance. The balanced modules have dies with similar threshold voltages while the unbalanced modules have dies with unbalanced threshold voltages to force unbalanced current sharing. The modules were placed into a clamped inductive DPT and a continuous, boost converter. Rogowski coils looped under the wire bonds of the bottom switch dies to observe current behavior. Four modules performed continuously for least 10 minutes at 200 V, 37.6 A input, at 30 kHz with 50% duty cycle. The modules could not perform for multiple minutes at 250 V with 47.7 A (23 A/die). The energy loss differential for a ~17% difference in threshold voltage ranged from 4.52% (~10 µJ) to -30.9% (~30 µJ). The energy loss differential for a ~0.5% difference in V_th ranged from -2.26% (~8 µJ) to 5.66% (~10 µJ). The loss differential was dependent on whether current unbalance due to on-state resistance compensated current unbalance due to threshold voltage. While device parametric tolerances are inherent, if the higher threshold voltage devices can be paired with devices that have higher on-state resistance, the overall loss differential may perform similarly to well-matched dies. Lastly, the most consistently performing unbalanced module with 17.7% difference in V_th had 119.9 µJ more energy loss and was 22.2°C hotter during continuous testing than the most consistently performing balanced module with 0.6% difference inV_th. / Master of Science / This paper describes the design, construction, and testing of advanced power devices for use in electric vehicles. Power devices are necessary to supply electricity to different parts of the vehicle; for example, energy is stored in a battery as direct current (DC) power, but the motor requires alternating current (AC) power. Therefore, power electronics can alter the energy to be delivered as DC or AC. In order to carry more power, multiple devices can be used together just as 10 people can carry more weight than 1 person. However, because the devices are not perfect, there can be slight differences in the performance of one device to another. One device may have to carry more current than another device which could cause failure earlier than intended. In this research project, multiple power devices were placed into a package, or "module." In a control module, the devices were selected with similar properties to one another. In an experimental module, the devices were selected with properties very different from one another. It was determined that the when the devices were 17.7% difference, there was 119.9 µJ more energy loss and it was 22.2°C hotter than when the difference was only 0.6%. However, the severity of the difference was dependent on how multiple device characteristics interacted with one another. It may be possible to compensate some of the impact of device differences in one characteristic with opposing differences in another device characteristic.