996 resultados para Temporal Precision
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Dissertação de Mestrado, Biologia Marinha, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015
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Dissertação de Mestrado, Biologia Marinha, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016
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The speed control system for a concept for cost effective drives with high precision is presented. The drive concept consists of two parallel working drives. The concept is an alternative to direct drives. One big advantage is the use of standard gear boxes with economical components. This paper deals with the control of the drive system consisting of two parts: one drive produces the power for the machine, another drive makes the motion precice and dynamic. Both drives are combined to one double drive by a control system. The drive system is usefull for printing machines and other machines with high power consumption at a nearly constant speed and high accuracy requirements. The calculation for a drive system with 37 kW shows, that the control drive has to supply only about 20 % of the total torque and power needed to compensate the errors of the power drive. The stability of the system is shown by a simulation of the double drive.
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The speed control system for a concept for cost effective drives with high precision is presented. The drive concept consists of two parallel working drives. The concept is an alternative to direct drives. One big advantage is the use of standard gear boxes with economical components. This paper deals with the control of the drive system consisting of two parts: one drive produces the power for the machine, another drive makes the motion precice and dynamic. Both drives are combined to one double drive by a control system. The drive system is usefull for printing machines and other machines with high power consumption at a nearly constant speed and high accuracy requirements. The calculation for a drive system with 37 kW shows, that the control drive has to supply only about 20 % of the total torque and power needed to compensate the errors of the power drive. The stability of the system is shown by a simulation of the double drive.
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Tese de doutoramento, Geografia (Geografia Física), Universidade de Lisboa, Instituto de Geografia e Ordenamento do Território, 2014
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Geographical and temporal variations in the start dates of grass pollen seasons are described for selected sites of the European Pollen Information Service. Daily average grass pollen counts are derived from Network sites in Finland, the Netherlands, Denmark, United Kingdom, Austria, Italy and Spain, giving a broad longitudinal transect over Western Europe. The study is part of a larger project that also examines annual and regional variations in the severity, timing of the peak and duration of the grass pollen seasons. For several sites, data are available for over twenty years enabling long term trends to be discerned. The analyses show notable contrasts in the progression of the seasons annually with differing lag times occurring between southern and northern sites in various years depending on the weather conditions. The patterns identified provide some insight into geographical differences and temporal trends in the incidence of pollinosis. The paper discusses the main difficulties involved in this type of analysis and notes possibilities for using data from the European Pollen Information service to construct pan European predictive models for pollen seasons.
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Tese de doutoramento, Informática (Ciências da Computação), Universidade de Lisboa, Faculdade de Ciências, 2015
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Detailed surveys of depth and velocity are undertaken to describe hydro-ecological status of rivers. Fieldwork for these surveys is time consuming and expensive. This paper aims to describe the methodology applied in order to determine the most suitable depth sampling strategy for effective field data collection and river representation in time and space at the Leigh Brook river site, Worcester, UK. The accuracy of three different sampling strategies for predicting depth at non-measured points has been compared and the mesohabitats that better characterise depth changes due to variations in discharge have been identified. The results show that depth changes due to discharge change are mainly located at shallow and deep glide mesohabitat types. The analysis for the comparison of sampling strategies indicates that grid sampling strategies give better results than regular transects. Since the results also show that higher errors in predictions are obtained in the deepest areas, higher sampling densities should be applied in these locations.
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Senior thesis written for Oceanography 444
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This thesis takes a theoretical and practical approach to data visualization, focusing in particular on interactive timelines as a means to mapping historical/cultural narratives. It seeks to understand how timelines can efficiently communicate a historical narrative, enhancing the topic’s comprehension whilst relating it to the surrounding context. For this purpose, an interactive timeline on Design in Portugal from 1900 to present, was conceptualized and developed. The research adopted a descriptive methodology. The theoretical framework depicts the basic concepts, models and taxonomies associated to timelines, which derive from the main studies available on the matter. From this, a model for the analysis of three case studies – Idea Line (2002), The Path of Protest (2011) and British History Timeline (2006) – was proposed. The selection criteria shows that they refer to interactive timelines depicting a historical narrative, in addition to being as heterogeneous as possible with respect to the themes presented and conveyed purposes. The comparative analysis produced a set of thoughts, conclusions and principles, subsequently considered and applied in the development of the timeline presented. The results of this study point to the decisive role of visual setup of the time axis and user tasks in the interpretation of information. The effective implementation of the timeline Design in Portugal: from 1900 to present, contributes to the study of timelines as information devices with its own characteristics and capabilities, promotes associated research and theoretical systematization and, on a pragmatic note, helps creating the basis for the gathering, compilation and presentation of relevant information on design in Portugal, providing the academic and professional community with an effective tool for referring and learning
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Existing Workflow Management Systems (WFMSs) follow a pragmatic approach. They often use a proprietary modelling language with an intuitive graphical layout. However the underlying semantics lack a formal foundation. As a consequence, analysis issues, such as proving correctness i.e. soundness and completeness, and reliable execution are not supported at design level. This project will be using an applied ontology approach by formally defining key terms such as process, sub-process, action/task based on formal temporal theory. Current business process modelling (BPM) standards such as Business Process Modelling Notation (BPMN) and Unified Modelling Language (UML) Activity Diagram (AD) model their constructs with no logical basis. This investigation will contribute to the research and industry by providing a framework that will provide grounding for BPM to reason and represent a correct business process (BP). This is missing in the current BPM domain, and may result in reduction of the design costs and avert the burden of redundant terms used by the current standards. A graphical tool will be introduced which will implement the formal ontology defined in the framework. This new tool can be used both as a modelling tool and at the same time will serve the purpose of validating the model. This research will also fill the existing gap by providing a unified graphical representation to represent a BP in a logically consistent manner for the mainstream modelling standards in the fields of business and IT. A case study will be conducted to analyse a catalogue of existing ‘patient pathways’ i.e. processes, of King’s College Hospital NHS Trust including current performance statistics. Following the application of the framework, a mapping will be conducted, and new performance statistics will be collected. A cost/benefits analysis report will be produced comparing the results of the two approaches.
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Existing Workflow Management Systems (WFMSs) follow a pragmatic approach. They often use a proprietary modelling language with an intuitive graphical layout. However the underlying semantics lack a formal foundation. As a consequence, analysis issues, such as proving correctness i.e. soundness and completeness, and reliable execution are not supported at design level. This project will be using an applied ontology approach by formally defining key terms such as process, sub-process, action/task based on formal temporal theory. Current business process modelling (BPM) standards such as Business Process Modelling Notation (BPMN) and Unified Modelling Language (UML) Activity Diagram (AD) model their constructs with no logical basis. This investigation will contribute to the research and industry by providing a framework that will provide grounding for BPM to reason and represent a correct business process (BP). This is missing in the current BPM domain, and may result in reduction of the design costs and avert the burden of redundant terms used by the current standards. A graphical tool will be introduced which will implement the formal ontology defined in the framework. This new tool can be used both as a modelling tool and at the same time will serve the purpose of validating the model. This research will also fill the existing gap by providing a unified graphical representation to represent a BP in a logically consistent manner for the mainstream modelling standards in the fields of business and IT. A case study will be conducted to analyse a catalogue of existing ‘patient pathways’ i.e. processes, of King’s College Hospital NHS Trust including current performance statistics. Following the application of the framework, a mapping will be conducted, and new performance statistics will be collected. A cost/benefits analysis report will be produced comparing the results of the two approaches.
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Introdução: A disfunção temporomandibular (DTM), de causa muscular, caracteriza-se por uma dor músculo-esquelética crónica, com sinais e sintomas específicos como a presença de Trigger Points (TrPs). Objetivo: Avaliar o efeito da Técnica de Inibição de Jones (TIJ) nos músculos masseter e temporal em indivíduos com DTM, e a identificação dos sinais e sintomas, a relação entre a severidade da DTM, a ansiedade e a qualidade de sono. Métodos: Estudo quasi-experimental, constituído por 16 indivíduos no grupo experimental (GE) e 17 grupo controle (GC). O grau de severidade foi avaliado pelo Índice de Helkimo e as alterações do sono pelo questionário de Pittsburgh sobre a qualidade do sono. Apenas o GE foi sujeito a uma TIJ nos TrPs latentes dos músculos masseter e temporal. Os dois grupos foram avaliados pré-intervenção (M0), pós-intervenção (M1) e 3 semanas após (M2), as amplitudes de movimento ativas de abertura, lateralidade direita/esquerda e protusão da boca bem como a dor (EVA) em repouso e na abertura máxima. Resultados: Foi possível observar que quanto maior o grau de DTM, maior a frequência de ansiedade e pior a qualidade do sono. Observou-se um decréscimo de TrPs, no GE, após a aplicação da técnica, principalmente no masseter. Não foi possível verificar diferenças inter-grupos. Contudo, observou-se no GE uma melhoria em todas as amplitudes avaliadas entre o M0 e o M2. Em relação à EVA em repouso e na abertura máxima, o GE demonstrou diminuição da dor no M1 e manteve valores inferiores no M2. Conclusão: Verifica-se uma diminuição dos TrPs, uma melhoria das amplitudes ativas bem como uma diminuição da dor após a aplicação da TIJ no GE. Já ao longo do tempo, o efeito é menos expressivo contudo observam-se valores inferiores comparativamente a M0.
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Renewable energy sources (RES) have unique characteristics that grant them preference in energy and environmental policies. However, considering that the renewable resources are barely controllable and sometimes unpredictable, some challenges are faced when integrating high shares of renewable sources in power systems. In order to mitigate this problem, this paper presents a decision-making methodology regarding renewable investments. The model computes the optimal renewable generation mix from different available technologies (hydro, wind and photovoltaic) that integrates a given share of renewable sources, minimizing residual demand variability, therefore stabilizing the thermal power generation. The model also includes a spatial optimization of wind farms in order to identify the best distribution of wind capacity. This methodology is applied to the Portuguese power system.