This thesis develops a robust methodology for on-line identification of power system dynamic signature based on incoming system responses from Phasor Measurement Units (PMUs) in Wide Area Measurement Systems (WAMS). Data mining techniques are used in the methodology to convert real-time monitoring data into transient stability information and the pattern of system dynamic behaviour in the event of instability. The future power system may operate closer to its stability limit in order to improve its efficiency and economic value. The changing types and patterns of load and generation are resulting in highly variable operating conditions. Corrective control and stabilisation is becoming a potentially viable option to enable safer system operation. In the meantime, the number of WAMS projects and PMUs is rising, which will significantly improve the system situational awareness. The combination of all these factors means that it is of vital importance to exploit a new and efficient Transient Stability Assessment (TSA) tool in order to use real-time PMU data to support decisions for corrective control actions. Data mining has been studied as the innovative solution and considered as promising. This work contributes to a number of areas of power systems stability research, specifically around the data driven approach for real-time emergency mode TSA. A review of past research on on-line TSA using PMU measurements and data mining is completed, from which the Decision Tree (DT) method is found to be the most suitable. This method is implemented on the test network. A DT model is trained and the sensitivity of its prediction accuracy is assessed according to a list of network uncertainties. Results showed that DT is a useful tool for on-line TSA for corrective control approach. Following the implementation, a generic probabilistic framework for the assessment of the prediction accuracy of data mining models is developed. This framework is independent of the data mining technique. It performs an exhaustive search of possible contingencies in the testing process and weighs the accuracies according to the realistic probability distribution of uncertain system factors, and provides the system operators with the confidence level of the decisions made under emergency conditions. After that, since the TSA for corrective control usually focuses on transient stability status without dealing with the generator grouping in the event of instability, a two-stage methodology is proposed to address this gap and to identify power system dynamic signature. In this methodology, traditional binary classification is used to identify transient stability in the first stage; Hierarchical Clustering is used to pre-define patterns of unstable dynamic behaviour; and different multiclass classification techniques are investigated to identify the patterns in the second stage. Finally, the effects of practical issues related to WAMS on the data mining methodologies are investigated. Five categories of issues are discussed, including measurement error, communication noise, wide area signal delays, missing measurements, and a limited number of PMUs.

[pt] Neste trabalho estuda-se um sistema de acompanhamento de alvos, também conhecido como sistema de rastreamento de alvos, do tipo pan-tilt atuado por motores de corrente contínua e fixo em um corpo em movimento. Para tanto é montada uma bancada de testes e implementa-se um programa de simulação. A modelagem para o programa é feita no domínio do tempo, permitindo a utilização de equações bastante complexas para representar o sistema, o que não é possível quando se utiliza modelos no domínio da freqüência. Apesar de se modelar o sistema com corpos rígidos, flexibilidades e amortecimentos estruturais devido aos redutores de velocidade são considerados. Erros nos sensores, folgas nos redutores, atritos seco e viscoso, limites de saturação para as correntes e tensões nas armaduras dos motores também são considerados. Um método para a inclusão dos atrasos de tempo para atualização dos sinais de controle e dados obtidos pelos sensores durante a integração numérica das equações de movimento é apresentado. Para controlar o sistema utilizam-se controladores que não requerem o modelo matemático da planta, tanto na bancada de testes como no programa de simulação. Três tipos diferentes de arquitetura de controle são propostas, chamadas neste trabalho de tipo 1, tipo 2 e tipo 3. A complexidade delas aumenta à medida que mais sensores estão disponíveis no sistema. A arquitetura do tipo 1 destina-se a sistemas onde se possui apenas sensores que fornecem os erros angulares de azimute e elevação do alvo. Se, além deste sensor, também houver sensores para medir as posições angulares relativas entre os elos do mecanismo usa-se a arquitetura do tipo 2. Se houver, ainda, sensores de velocidades angulares inerciais pode-se utilizar a arquitetura do tipo 3. Por fim são apresentados resultados de experimentos e simulações onde se compara o desempenho do sistema com cada tipo de arquitetura de controle. / [en] A study on a pan-tilt type target tracking system actuated by permanent magnet DC motors and assembled in a moving body is presented in this work. To achieve such objective, an experimental test bed is constructed and a simulation program is implemented. The mechanical model is derived and simulated in time domain. This approach allows using accurate non-linear equations to represent system behavior, otherwise infeasible in frequency domain. Although the system is modeled with rigid bodies, flexibility and structural damping due to the gearboxes are considered. Sensor errors, backlash in the gearboxes, dry and viscous friction, saturation limits for armature current and tension of the motors are also considered. A method to include the time delays for the control signal updates, as well as time delays due to sensor dynamic response, during the numerical integration of the equations of motion, is presented. Controllers that require no mathematical model of the plant are employed in the experimental test bed and in the simulation program. Three different control architectures are proposed, called in this work type 1, type 2 and type 3. Their complexity increases depending on the number of available sensors. The type 1 is applied to systems with only one sensor that provides the targets angular azimuth and elevation errors. If, besides this sensor, sensors to measure the relative angular positions between the mechanism links are available type 2 architecture is used. In addition, if sensors to measure inertial angular speeds are also available, type 3 architecture can be used. Finally, experimental and numerical results, comparing system performance with each control architecture are presented.

Metapolybia wasps construct their nests on flat surfaces using plant materials, which they process into paper. For processing the pulp wasps need water, which is collected by water foragers, and it is transferred to pulp foragers indirectly via a "common stomach." The common stomach is formed by generalist wasps that can engage in water exchange and can store water in their crops. Our goal is to provide an alternative model for regulating task partitioning in construction behavior, focusing on worker connectivity instead of using threshold curves to model mechanisms of colony-level regulation. We propose that the existence of an information center and of a network of worker interactions, which establish sets of positive and negative feedbacks, allow collective regulation of colony-wide behaviors. Using a Stock and Flow modeling framework, we illustrate that the common stomach could serve both as a temporal storage for water and also as a source of information about the colony's current demands related to nest construction tasks. Our model predicts that assessing colony needs via individual interactions with the common stomach leads to a robust regulation of task partitioning in construction behavior. Using perturbation experiments in our simulations, we show that this emergent task allocation is able to dynamically adapt to perturbations of the environment and to changes in colony-level demands or population structure. Our model closely mimics and predicts the behavior of Metapolybia wasps, demonstrating that the regulation mechanism based on worker connectivity through a common stomach is a plausible hypothesis for the organization of collective behavior.

Yes / Applying the circular economy (CE) concept is crucial for achieving sustainable development goals. A transition towards a CE requires new tools to clarify the interdependency among systems and assist policy-makers in their decisions, particularly in the risk assessment field. This paper analyzes the systemic effects and interdependencies of several risks in the context of a CE. The developed tool helps adopt proactive strategies that consider the four aspects of sustainability (economic, environmental, social, and technological). The adopted tool improves strategic thinking for a circular economy concept and supports organizations with respect to assessing risks. This paper aims to provide a comprehensive and novel model to quantify the priority weights of the sustainability risk indicators to provide guidelines for supporting the policy formulation process for decision-makers. In this paper, the taxonomy of various risk indicators has been proposed, and we have identified and adopted 40 risk indicators for the CE. This paper focuses on understanding how risks can be constructed and how they affect the performance of power plants over time in terms of availability, efficiency, and operational and maintenance cost. The causal loop diagram (CLD) model is built by deploying various risk quantifications, and the adopted tool was tested and validated to assess the CE risks relevant to the environmental perspective in power plants in the Middle East. The risk indicators under the concept of the CE model and the system thinking approach can help policy-makers in their strategic and operational decision-making process for achieving a better understanding of the risk assessment process. The taxonomy of risk categories and its linking with the system thinking approach will help in the successful and effective implementation of a CE in the energy sector in the long-term. The proposed model offers a tool for policy-makers to design policies when planning a CE.

Esse trabalho investiga o impacto do comportamento transitório e em regime permanente da carga sobre a estabilidade de tensão do sistema elétrico. Para isso, utiliza-se uma modelagem detalhada da rede elétrica, capaz de representar os principais eventos inerentes aos fenômenos de instabilidade e colapso de tensão. A simulação numérica do sistema algébrico-diferencial resultante é realizada utilizando-se o solver DASSLC. Ao final desse trabalho, faz-se uma análise da resposta dos diferentes modelos de carga sobre a estabilidade de tensão do sistema de 14 barras do IEEE. / This work investigates the impact of transient and steady state load behavior on power systems voltage stability. In order to do this, a detailed electric power system model is used to reproduce the main aspects of voltage instability and collapse phenomena. The numerical solution of the resulting non-linear differential-algebraic equations is carried out by using the DASSLC solver. An analysis of different load models behaviour for some voltage instability situations is presented for IEEE 14 bus system.

Esse trabalho investiga o impacto do comportamento transitório e em regime permanente da carga sobre a estabilidade de tensão do sistema elétrico. Para isso, utiliza-se uma modelagem detalhada da rede elétrica, capaz de representar os principais eventos inerentes aos fenômenos de instabilidade e colapso de tensão. A simulação numérica do sistema algébrico-diferencial resultante é realizada utilizando-se o solver DASSLC. Ao final desse trabalho, faz-se uma análise da resposta dos diferentes modelos de carga sobre a estabilidade de tensão do sistema de 14 barras do IEEE. / This work investigates the impact of transient and steady state load behavior on power systems voltage stability. In order to do this, a detailed electric power system model is used to reproduce the main aspects of voltage instability and collapse phenomena. The numerical solution of the resulting non-linear differential-algebraic equations is carried out by using the DASSLC solver. An analysis of different load models behaviour for some voltage instability situations is presented for IEEE 14 bus system.

Water scarcity is both natural and man-made phenomenon. Water control and uneven distribution of upstream TeestaRiver water makes artificial scarcity in downstream areas which can be minimized at least to the water stress level by balancing distribution and sustainable water use. Tasseled Cap transformation and NDVI methods were used in this study in order to find the magnitude of water scarcity in the downstream areas. NDVI and Tasseled Cap Greenness methods were applied to get proxy for soil moisture values in the form of biomass content and Tasseled Cap Wetness method were used to detect change in soil moisture content from Landsat TM and ETM+ data (1989-2010). System dynamic analysis method was applied to identify temporal and spatial differences between supply and demand of water in the TeestaRiver catchments area in the northwestern part of Bangladesh. It was found that, the vegetation cover and soil moisture content changed and shifted over time. Overall vegetation declined between 1989 and 2010 and soil moisture content also turned down. Moreover, TeestaRiver water is playing an important role for maintaining the balance between water supply and water scarcity in this region. There is a correlation between water scarcity in the downstream and availability of water in the TeestaRiver during dry seasons. / Master's Thesis

I ABSTRACT Autor: Mgr. Helena Vomáčková Title: The Possibilities of Evaluation of the Sport Performance on the Postural Functions - CDP Normative Data for Sport Population Objective: The main aim of the dissertation is to determine the standardized values (normative data) of individual parameters of test protocols obtainable with usage of dynamic computer posturography of the NeuroCom SMART EquiTest System (hereinafter SMEQ). The partial second goal is to compare the determined normative data with the existing values used for routine evaluation of postural stability given by the SMEQ software. Another partial goal is to determine the reliability of individual test parameters in an additional pilot survey. Methods: Data for the determination of standardized values were obtained by laboratory measurements using the SMEQ system and subsequently were converted, unified and adjusted for further processing by statistical "software R". To determine the normative data, an input data-set obtained from a deliberately selected group of active athletes (n = 245) in the selected age range of 20 - 30 years with an average age of 24,04 (± 1,23 years), with an average body height of 173, 29 (± 10,04 cm), mean body weight 68,46 (± 13,10 kg) and mean BMI 22,67 (± 3,04) was used. To calculate the predicted normative data for...

As buildings have become more energy efficient, the energy demand for preparation of domestic hot water stands out as an increasing part of the operational cost and carbon footprint of a building. Most of the heat in the water is used for a short time and then discharged to the main sewer line. Clarion Hotel Stockholm is an example of such a building, with many showers, bathtubs and a spa. The hotel business is growing around the world and its customers demand comfortable stays. A parallel trend is a more environmentally aware tourism and business travel. Hotels show a great potential for energy savings, while still offering comfortable accommodation. In this master's thesis a case study evaluates the possibilities for heat recovery from the wastewater of Clarion Hotel Stockholm. Three types of heat exchangers were modelled in the system dynamic modelling environment STELLA: a horizontal, a vertical and a shower heat exchanger. Recovered heat was used for pre-heating of the incoming water for domestic hot water preparation. The flows of heat through the hotel's tap water and wastewater systems were schematically modelled using system dynamic modelling, which provides a foundation for the development of mathematical models and further research into the area. The first results point to possible reductions of the heating demand for domestic hot water preparation at Clarion Hotel Stockholm.

<p>Disertacijom su opisane postojeće tehnike redukcije dinamičkih modela koje se koriste u teoriji upravljanja i postojeće tehnike za redukciju dinamičkih modela i ekvivalentiranje elektroenergetskih sistema. Predložen je nov pristup na fizici problema zasnovanoj redukciji dinamičkog modela elektroenergetskog sistema korišćenjem teorije balansnih realizacija. Takođe se predlaže korišćenje aproksimativnih bisimulacionih relacija za redukciju dinamičkih modela elektroenergetskog sistema. Postojeće tehnike i predloženi pristupi i algoritmi su primenjeni za redukciju dinamičkih modela dva razmatrana test sistema.</p> / <p>Dissertation describes the existing dynamic model reduction techniques used in control theory and existing techniques that are used for the reduction (equivalencing) of power system dynamic models. A new approach to physics-based reduction of power system dynamic model based on the balanced realization theory is proposed. Use of approximate bisimulation relations for reduction of power system dynamic models is also proposed. Existing techniques and proposed approaches and algorithms are applied to reduce the dynamic models of two considered test systems.<br />&nbsp;</p>