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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Biogeodinâmica de herbicidas utilizados em cana-de-açúcar (Saccharum spp.) na sub-bacia do rio Corumbataí / Biogeodynamic of herbicides used in sugarcane (Saccharum spp.) at Corumbataí river watershed

Armas, Eduardo Dutra de 28 August 2006 (has links)
A sub-bacia hidrográfica do rio Corumbataí é de grande importância sócioeconômica no estado de São Paulo, cujo rio, de mesmo nome, tornou-se alvo de preocupação ainda maior nos últimos anos, quando passou a atender 100% do abastecimento do município de Piracicaba. Sendo explorada principalmente pela cultura da cana-de-açúcar e composta de solos com características físico-químicas distintas e relevo variando de plano a montanhoso, surge grande preocupação em torno do comportamento ambiental dos agrotóxicos empregados nesta bacia, o qual é desconhecido até o momento. O presente estudo teve por objetivo avaliar a biogeodinâmica dos agrotóxicos empregados em cana-de-açúcar nesta bacia hidrográfica, vindo a servir de subsídio aos processos de avaliação da qualidade da água desta bacia e definição de metas para o Plano de Bacias, elaborado pelo Comitê das Bacias dos Rios Piracicaba, Capivari e Jundiaí. Este trabalho consistiu de caracterização temporal do uso de agrotóxicos em cana-de-açúcar, o qual serviu de suporte na definição de moléculas e períodos de amostragem para o monitoramento de resíduos em água e sedimento na calha principal do rio Corumbataí e principais afluentes. A identificação de áreas críticas na sub-bacia para o aporte de agrotóxicos foi realizada por meio do modelo matemático SWAT. O estudo apontou o uso principalmente de herbicidas, sendo os únicos produtos de uso declarado no período de avaliação, com consumo sazonal de algumas moléculas e uso indistinto de outras ao longo do ano, o que permitiu um planejamento estratégico do monitoramento de resíduos. Os herbicidas glifosato, atrazina, ametrina, 2,4-D, metribuzim, diurom e acetocloro representaram aproximadamente 85% do volume total de produtos consumidos entre 2000 e 2003. Imazapir foi identificado como o herbicida de maior freqüência de uso, sendo também vislumbrado o emprego de moléculas de alta toxicidade e mobilidade, como sulfentrazona, trifloxissulfurom-sódico, paraquate, tebutiurom e imazapique. No monitoramento de resíduos, níveis quantificáveis de ametrina, atrazina, simazina, hexazinona, glifosato e clomazona foram detectados em amostras de água, com níveis desprezíveis de ametrina e glifosato em sedimento. A área de recarga do aqüífero Guarani, no norte da bacia, apresentou os níveis mais elevados de triazinas e clomazona. As triazinas representam o grupo de moléculas detectadas em níveis mais altos, com a atrazina superando os padrões de potabilidade e de qualidade de água para a vida aquática em alguns pontos. Estas moléculas foram também apontadas pela simulação, como as de maior tendência de ocorrer nos corpos hídricos superficiais e subterrâneos, quando aplicadas em período chuvoso, sendo superadas por glifosato em corpos hídricos superficiais, quando a aplicação ocorreu em período de seca. A simulação de um cenário de expansão da cultura de cana-de-açúcar resultou em aumento da participação das áreas com Areia Quartzosa para o aporte de herbicidas aos corpos hídricos, que juntamente com o Podzólico Vermelho-Amarelo, Podzólico Vermelho-Escuro e solos Litólicos, apresentaram maior vulnerabilidade na bacia. As regiões norte da bacia e as sub-bacias do Ribeirão Claro e rio Passa Cinco evidenciaram as maiores exportações de herbicidas aos corpos hídricos e níveis de resíduos em segmentos de rio após o período de chuva intensa. / The Corumbataí river watershed is of great socioeconomic importance in the state of São Paulo, which river, of the same name, became target of higher concern in the last years, when it started to assist 100% the provisioning of the municipal district of Piracicaba. Being explored mainly by the culture of sugarcane and composed of soils with different physicochemical characteristics and relief varying from plan to mountainous, great concern appears around the environmental behavior of pesticides employed in this basin, whose dynamics is ignored until then. The present study had for objective to evaluate the biogeodynamic of pesticides employed in sugarcane in this watershed, coming to serve from subsidy to the water quality evaluation processes of this basin and definition of goals for the Plan of Basins elaborated by the Watersheds Committee of Piracicaba, Capivari, and Jundiaí Rivers. This work consisted of temporal characterization of the use of pesticides on sugarcane, which served as support in the definition of molecules and sampling periods for the residue monitoring in water and sediment in the main channel of the Corumbataí river and main affluents. The identification of critical areas in the sub-basin for the contribution of pesticides was accomplished through the mathematical model SWAT. The study pointed the use mainly of herbicides, being the only one, whose use was declared in the evaluation period, with seasonal consumption of some molecules and use of others along the whole year, what allowed a residue monitoring strategic planning. The herbicides glyphosate, atrazine, ametryne, 2,4-D, metribuzin, diuron and acetochlor represented around 85% of the total volume of products consumed between 2000 and 2003. Imazapyr was identified as the herbicide of larger use frequency, being also observed the use of high toxicity and mobility molecules, as sulfentrazone, trifloxysulfuron-sodium, paraquat, tebuthiuron and imazapic. In the residue monitoring, quantifiable levels of ametryne, atrazine, simazine, hexazinone, glyphosate and clomazone were detected in water samples, with negligible levels of ametryne and glyphosate in sediment. The recharge area of the Guarani aquifer, in the north of the basin, presented the highest levels of triazines and clomazone. The triazines represent the group of molecules detected in higher levels, with the atrazine overcoming the water potability and quality standards for the aquatic life in some points. These molecules were pointed also for the simulation, as the one of larger tendency of happening in the surface waters and groundwaters, when applied in raining periods, being overcome by glyphosate in surface water bodies, when the application happened in dry period. The simulation of a sugarcane culture expansion scenery resulted in increase of the participation of the areas with Typic Quartzipsamment (Areia Quartzosa) for the herbicides contribution to the water bodies, which added with Typic Hapludult (Podzólico Vermelho-Amarelo), Rhodic Kandiudox (Podzólico Vermelho-Escuro) and Typic Udorthent (Litólico) soils, presented larger vulnerability in the basin. The north region of the Corumbataí river watershed and the sub-basins of Ribeirão Claro and Passa Cinco river showed the largest herbicide loadings to water bodies and levels of residues in river segments after the period of intense rain.
72

Avaliação de segurança em sistemas de controle de tráfego aéreo baseados em vigilância dependente automática por radiodifusão considerando parâmetros de integridade de dados. / Safety assessment in air traffic control systems based on automatic dependent surveillance broadcast by considering data integrity parameters.

Daniel Baraldi Sesso 17 October 2016 (has links)
A demanda pelo aumento do volume de tráfego aéreo tem pressionado as autoridades da aviação a adensar o espaço aéreo global, por meio de redução na separação entre aeronaves, permitindo operações mais eficientes no Gerenciamento de Tráfego Aéreo (ATM). No entanto, questões relacionadas com a segurança das operações de tráfego aéreo surgem quando se considera a possibilidade de reduzir a separação de aeronaves. Objetivamente, para maior eficiência e redução da separação, sem que isso afete significativamente a segurança, a posição vigiada das aeronaves deve aparecer de forma não só mais exata e precisa para o controlador de tráfego aéreo (ATCo), como deve ser mais fiável, o que envolve a integridades dessa informação. Essa pesquisa propõe avaliar os impactos que esses parâmetros têm nos níveis de segurança crítica (safety) no sistema de controle de tráfego aéreo (ATC) inserido no novo conceito de ATM Global (CNS/ATM). Para isso, foi realizada uma análise dos dados de erro de posicionamento do Sistema de Navegação Global por Satélites (GNSS) visando estabelecer seu comportamento. Esse comportamento é utilizado para modelar um sistema de controle de tráfego completo para fins de simulação e, adotando-se a metodologia de análise de segurança desenvolvida por Vismari (2007), avaliar os efeitos que esses novos parâmetros exercem sobre os níveis de segurança encontrados na pesquisa desenvolvida por Vismari (2007) para ambientes de tráfego aéreo baseados na Vigilância Dependente Automática por Radiodifusão (ADS-B). São comparados diversos cenários em que houve a degradação do comportamento do sistema GNSS. Para cada cenário estudado verificou-se que a degradação do comportamento não foi suficiente para gerar eventos de risco relacionados à integridade dos dados posicionais das aeronaves. Assim, dentro das condições simuladas, o sistema manteve os níveis de segurança crítica no que se refere à integridade do posicionamento das aeronaves apresentadas na tela do controlador de tráfego aéreo em operações de resolução de conflito. O modelo computacional desenvolvido possui diversas características que, apesar de não serem totalmente utilizadas na presente pesquisa, constituem um legado para pesquisas futuras e para a integração com a Plataforma Integrada para Ensaios de Sistemas Embarcados Críticos (PIpE-SEC) desenvolvida dentro do Grupo de Análise de Segurança (GAS) da EPUSP. / The demand for increasing air traffic volume has pressed aviation authorities to densify the global airspace through separation reduction between aircraft, allowing operations that are more efficient in the Air Traffic Management (ATM). However, issues related to the safety of air traffic operations arise when considering the possibility of reducing the separation of aircraft. Objectively, for greater efficiency and separation reduction, without significantly affecting safety, surveillance positions of the aircraft must appear not only more accurate and precise to the air traffic controller (ATCo), it should be more trustworthy, which concerns the integrity of that information. This research proposes to assess the impacts of these parameters on the safety levels of air traffic control system (ATC) inserted in the new concept of Global ATM (CNS/ATM). To achieve it, an analysis of the data related to error in positioning of the Global Navigation Satellite System (GNSS) was made to establish its behavior. This behavior analysis is used to model a complete traffic control system for simulation purposes and, adopting the safety analysis methodology developed by Vismari (2007), evaluate the effects that these new parameters had on the safety levels found in the research developed by Vismari (2007) for air traffic environments based on Automatic Dependent Surveillance - Broadcast (ADS-B). They are compared to various scenarios in which there was a GNSS system performance degradation. For each studied scenario, it was found that GNSS behavior\'s degradation was not sufficient to create risk events in aspects related to integrity of the aircraft position data. Thus, within the simulated conditions, the system kept the safety levels regarding to the integrity of the aircraft position informed on screen to the air traffic controller in conflict resolution operations. The computational model developed has several features, which, although not totally applied in this research, constitute a legacy for future research and for integration with the Integrated Platform for Testing Critical Embedded Systems (PIpE-SEC) developed within the Safety Analysis Group (GAS) of EPUSP.
73

Resultatpåverkan av olika fördelningar på parametern operationstid vid simuleringsstudier. : <html /> / <html /> : <html />

Bengtsson, Angelica, Kuc, Arlena January 2011 (has links)
I detta arbete har studerats hur flödet i en flerstegs- bearbetningsprocess påverkas av stokastiska fluktuationer och störningar i de enskilda processtegen. Mera bestämt har analys utförts av hur de stokastiska variationerna i operationstiderna kan och bör modelleras vid simuleringsstudier. Även hur påverkan av valet av sådana stokastiska modeller kan tänkas ha på processen i sin helhet, till exempel avseende total genomloppstid. Examensarbetet syftar till att undersöka hur val av fördelning på parametern operationstid, påverkar resultatfaktorn genomloppstid vid flödessimuleringar. För att finna svar på denna påverkan har en fallstudie utförts, med utgångspunkt av indata från en produkt som tillverkas på Volvo Aero. Denna produkt genomgår en tillverkningssekvens innehållande 18 stycken bearbetningsoperationer innefattande tre olika processtyper (automatisk, halvautomatisk och manuell). Dessa tre processtyper är i olika grad beroende av operatörers insats. De 18 bearbetningsoperationernas processtid har analyserats numeriskt och grafiskt. Programvaran Stat:fit har använts som hjälpmedel för att erhålla svar på lämplig fördelning per tillverkningsoperation samt vilka teoretiska fördelningar som är lämpliga att använda för de tre olika processtyperna. De rekommenderade fördelningsteorierna per tillverkningsoperation har genomgått fördelningstest (Chi2, Kolmogorov-Smirnov och Anderson-Darling) och använts som grund vid skapande av försöksplan till simuleringsstudien. Simuleringsstudien har utförts enligt försöksplan i programvaran Simul8. Samtliga körningar från simuleringsmodellen är statistiskt säkerställda med 95 % konfidensintervall. Fallstudien har visat att resultatpåverkan från operationstidernas fördelningstyp är relativt liten vid simulering av komplexa system där faktorer som nivå av tillverkningsvolym och tillgänglighet har större påverkan på resultatfaktorn genomloppstid. Vid enklare modeller utan begränsning i form av reducerad tillgänglighet synliggörs skillnad i simuleringsresultat av olika val av fördelning på parametern operationstid. Fördelningen av dessa simuleringsresultat styrks av den centrala gränsvärdessatsen, det vill säga att om antalet observerade värden är tillräckligt stort, uppträder resultatet som normalfördelat. / Discrete event simulation is used to imitate and analyze how systems change over time. The actual behavior of the variation in the system is interpreted by using discrete and continuous probability distributions. In the software program Simul8, simulation models are created based on the information collected from the production. Shifts, operation time and efficiency are examples of information required for the modeling process. The aim with this bachelor´s thesis was to investigate how different choice of probability distributions on the parameter operation time affects the result of a discrete event simulation. The thesis is a result of a case study performed at Volvo Aero Corporation, Sweden. The case study involves investigation of probability distribution for 18 manufacturing operations for a product. The manufacturing sequence consists of three different types of processes (automatic, semiautomatic and manual). These three types of processes need different level of instrumentality. The commercial statistical computer software, Stat:fit has been used to find proper probability distribution for each of the manufacturing operations. The results from Stat:fit have been used to analyze if there are any connections between the process type and the probability distributions. The recommended probability distributions have been tested with Goodness-of-fit tests (Chi2, Kolmogorov-Smirnov and Anderson-Darling) using Stat:fit and used in the simulation modeling. The simulation model has been validated and verified by a simulation advisor at Volvo Aero. Five different simulation models have been evaluated in Simul8, with five different types of distributions. All simulation runs have been statistical proved, in Simul8 with 95% confidence interval. The result of this study indicates that the variation of process time has limited effect for complex simulation models containing low level of efficiency and high load factors, concerning the result of throughput time. For simple models, excluded from restricted efficiency, the effect on the throughput time is featured.
74

Ordnungsreduktion in der Mikrosystemtechnik

Gugel, Denis 19 July 2010 (has links) (PDF)
Die vorliegende Arbeit befasst sich mit der Methode der modalen Superposition als Ordnungsreduktionsverfahren in der Mikrosystemtechnik. Typische Anwendungsgebiete sind Inertialsensoren und dabei im Besonderen Drehratensensoren, für die die Simulation von zeitabhängigen Phänomenen von entscheidender Bedeutung ist. Im Rahmen der Weiterentwicklung der Ordnungsreduktion nach der Methode der modalen Superposition ist es gelungen für typische lineare Kräfte eine auf analytischen Gleichungen basierende Beschreibung im reduzierten Raum zu finden. Für die Beschreibung von nichtlinearen Kräften ist im Rahmen dieser Arbeit ein Verfahren entwickelt worden, das es erlaubt, bestehende Modelle im Finite-Elemente-Raum in der modalen Beschreibung zu nutzen. In dieser Arbeit werden die theoretischen Grundlagen zur Berücksichtigung von Einflüssen der Aufbau- und Verbindungstechnik in ordnungsreduzierten Modellen dargestellt. Neben der Einkopplung äußerer Kräfte und der Veränderung der mechanischen Randbedingungen wird auch der Einfluss der Aufbau- und Verbindungstechnik auf die elektrostatischen Eigenschaften untersucht. Die Parametrisierung des Verfahrens der modalen Superposition über Fit- und Interpolationsverfahren erlaubt es, parametrisierte ordnungsreduzierte Modelle für die zeitabhängige Systemsimulation zu generieren. Damit wird die Durchführung von Designoptimierung und die Berücksichtigung von Fertigungs- und Prozessschwankungen in ordnungsreduzierten Modellen auf Systemebene möglich.
75

Αρμονικές φωτοβολταϊκού συστήματος συνδεδεμένου στο δίκτυο : μια νέα μέθοδος ανάλυσης της ισχύος παρουσία αρμονικών

Μέντη, Ανθούλα 20 October 2009 (has links)
Στην παρούσα διατριβή αναπτύσσονται κατάλληλα μοντέλα για τις επιμέρους μονάδες φωτοβολταϊκού (ΦΒ) συστήματος συνδεδεμένου στο δίκτυο. Στόχος είναι να αντιμετωπιστούν ταυτόχρονα και αποτελεσματικά οι ιδιαιτερότητές του, που οφείλονται στη συμπεριφορά των διακοπτικών στοιχείων και στα μη γραμμικά χαρακτηριστικά της ΦΒ γεννήτριας και του μετασχηματιστή απομόνωσης. Αναπτύσσονται μέθοδοι που αυξάνουν την ταχύτητα εξομοίωσης. Αυτό επιτυγχάνεται με χρήση αυξητικών μοντέλων για τα μη γραμμικά στοιχεία και αποτελεσματικών αλγορίθμων για την αντιμετώπιση της μεταβλητής τοπολογίας. Τα μοντέλα που παρουσιάζονται μπορούν να χρησιμοποιηθούν για συνδεδεμένα στο δίκτυο ΦΒ συστήματα οποιασδήποτε διάταξης. Μέσω εξομοιώσεων της λειτουργίας ενός οικιακού ΦΒ συστήματος συνδεδεμένου στο δίκτυο διερευνάται η ευαισθησία της αρμονικής παραμόρφωσης τάσεων και ρευμάτων σε μεταβολές παραμέτρων του συστήματος. Στη συνέχεια παρουσιάζεται ένα νέο μοντέλο για τη ροή ενέργειας σε κυκλώματα με μη ημιτονοειδείς κυματομορφές. Το μοντέλο παρέχει μαθηματική περιγραφή μέσω του πολυδιανύσματος της ισχύος, το οποίο γεφυρώνει το χάσμα μεταξύ στιγμιαίας και φαινομένης ισχύος, όπως η μιγαδική ισχύς υπό ημιτονοειδείς συνθήκες. Το πολυδιάνυσμα της ισχύος επιτρέπει συστηματική και ενιαία αντιμετώπιση όλων των περιπτώσεων. Το μοντέλο ροής ενέργειας που παρουσιάζεται περιγράφει τις συνιστώσες ισχύος όχι μόνο ποσοτικά, αλλά και ποιοτικά. Από φυσικής πλευράς βασίζεται στη γενίκευση της έννοιας της αμοιβαίας σύζευξης. Η προσέγγιση που ακολουθείται επιτρέπει την φυσική ερμηνεία όλων των συνιστωσών της ισχύος, οι οποίες συνδέονται με μια αναπαράσταση μέσω ισοδυνάμου κυκλώματος. Οι προϋπάρχουσες μέθοδοι μπορούν να προκύψουν ως ειδικές περιπτώσεις του μοντέλου. Η βαθύτερη κατανόηση των φαινομένων ισχύος που παρέχει θέτει το θεωρητικό υπόβαθρο για την επίλυση πρακτικών προβλημάτων, όπως η αντιστάθμιση. Ακολούθως εξετάζεται η επιλογή του βέλτιστου μεγέθους παθητικών φίλτρων με παράλληλους συντονιζόμενους κλάδους. Η διερεύνηση λαμβάνει υπόψη όχι μόνο πηγές αρμονικών ρευμάτων λόγω μη γραμμικών φορτίων αλλά και την παρουσία προϋπάρχουσας αρμονικής παραμόρφωσης της τάσης. Μέσω αναλυτικής μεθόδου προκύπτουν εκφράσεις κλειστής μορφής για απλοποιημένες περιπτώσεις. Αυτές μπορούν να βοηθήσουν στην κατανόηση της επίδρασης διαφόρων παραμέτρων. Επίσης διαμορφώνεται η γενικότερη περίπτωση του προβλήματος και αντιμετωπίζεται με Γενετικούς Αλγόριθμους. Μέσα από εκτεταμένες εξομοιώσεις για διάφορα επίπεδα αρμονικών τάσης και ρεύματος, διερευνώνται διεξοδικά οι δυνατότητες των παθητικών φίλτρων. Τα πρακτικά συμπεράσματα που προκύπτουν μπορούν να βοηθήσουν στη λήψη αποφάσεων για τον έλεγχο των αρμονικών σε διάφορες εφαρμογές. / In this thesis, appropriate models for the individual components of a grid-connected photovoltaic (PV) system are developed. The aim is to simultaneously and efficiently handle its peculiarities, which are due to the switching action of the switching devices and the nonlinear characteristics of the PV generator and the isolation transformer. Methods that increase simulation speed are developed. This is accomplished by using incremental models for the nonlinear components and efficient algorithms to handle the variable topology. The presented models can be used for grid-connected PV systems of any configuration. Through simulations of the performance of a residential grid-connected PV system the sensitivity of the harmonic distortion of voltages and currents to variations in system parameters is investigated. Next, a novel model for the energy flow in circuits with nonsinusoidal waveforms is presented. This model provides a mathematical description through the power multivector, which bridges the gap between the instantaneous and apparent power, like the complex power does under sinusoidal conditions. The power multivector permits a systematic and uniform treatment of all cases. The presented energy flow model describes power components not only quantitatively but also qualitatively. From a physical perspective it is based on the generalization of the concept of mutual coupling. The approach that is followed permits the physical interpretation of all power components, which are associated with an equivalent circuit representation. Pre-existing methods can be derived as special cases of the model. The deeper understanding of power phenomena it provides sets the theoretical foundation for the solution of practical problems, such as compensation. Next, the optimal sizing of shunt, passive, single-tuned filters is examined. The investigation takes into account not only harmonic current sources due to nonlinear loads but also the presence of background voltage harmonic distortion. Through an analytical approach closed-form expressions are derived for simplified cases. These can help in the comprehension of the influence of various parameters. Moreover, the general case of this problem is formulated and solved using Genetic Algorithms. Through extensive simulations for various current and voltage harmonic levels, the potentialities of these filters are thoroughly investigated. The practical conclusions that are drawn can facilitate decisions regarding harmonic control in various applications.
76

Hibridinių sistemų modeliavimas naudojant agregatinį metodą / The use of piece-linear aggregates for specification and simulation of hybrid systems

Simaitis, Laurynas 16 August 2007 (has links)
Šiame darbe pristatomas PLA formalizmo metodas, skirtas aprašyti ir imituoti hibridines sistemas, kurių tolydiniai komponentai aprašomi pirmos eilės diferencialinėmis lygtimis. Pasinaudojus PLA formalizmu suformuluosime Kvantuotų būsenų sistemos modelį (QSS). QSS modelis yra integravimu pagrįstas metodas, skirtas spręsti pirmos eilės diferencialines lygtis. Šis modelis buvo suformuluotas DEVS formalizmo aplinkoje, kuris yra giminingas PLA formalizmui. Hibridinės sistemos pavyzdžiu pasirinktas farmakokinetinis modelis. Farmakokinetika yra farmakologijos mokslo šaka, tyrinėjant vartojamų vaistų pasisavinimą ir absorbciją žmogaus kūne. Farmakokinetiniame modelyje vaistų pasiskirstymas aprašomas pirmos eilės diferencialines lygtimis. Tam, kad būtų galima aprašyti šį modelį QSS pagalba, buvo reikalinga patobulinti QSS modelį. Rezultate gautas pakeistas QSS modelis. Naudojant pakeistą QSS modelį buvo sudarytas farmakokinetinis modelis ir atliktas vaistų koncentracijos kitimo imitavimas paciento kūne, kai pacientas reguliuoja vaistų suleidimą. / This paper presents the method of using Piece Linear Aggregates formalism (PLA) for specification and simulation of hybrid systems, when continuous components are described in ordinary differential equations (ODEs). PLA is used to create Quantized State System (QSS) model. QSS is integration based method, created for ODE solving. Since QSS method first was introduced for use in Discreet Event Systems (DEVS) formalism, we adapted it for PLA formalism, which is fundamentally consanguineous to DEVS formalism. Pharmacokinetics model is used as example of hybrid system. Pharmacokinetics is a branch of pharmacology which describes administered drug absorption and distribution in human body. In pharmacokinetics drug distribution is described using ODE. In order to use drug injection in pharmacokinetics model, we have to modify standard QSS model and add some specific capabilities. In the result: modified QSS method was obtained and used for pharmacokinetic model specification. Simulation of morphine concentration in plasma was performed using real pharmacokinetics data to test Patient-Controlled Analgesia method effectiveness.
77

Open Pit Truck /shovel Haulage System Simulation

Cetin, Necmettin 01 October 2004 (has links) (PDF)
This thesis is aimed at studying the open pit truck- shovel haulage systems using computer simulation approach. The main goal of the study is to enhance the analysis and comparison of heuristic truck dispatching policies currently available and search for an adaptive rule applicable to open pit mines. For this purpose, a stochastic truck dispatching and production simulation program is developed for a medium size open pit mine consisting of several production faces and a single dump site using GPSS/H software. Eight basic rules are modeled in separate program files. The program considers all components of truck cycle and normal distribution is used to model all these variables. The program asks the user to enter the number of trucks initially assigned to each shovel site. Full-factorial simulation experiments are made to investigate the effects of several factors including the dispatching rules, the number of trucks operating, the number of shovels operating, the variability in truck loading, hauling and return times, the distance between shovels and dump site, and availability of shovel and truck resources. The breakdown of shovel and trucks are modeled using exponential distribution. Three performance measures are selected as truck production, overall shovel utilization and overall truck utilizations. Statistical analysis of the simulation experiments is done using ANOVA method with Minitab software. Regression analysis gives coefficient of determination values, R2, of 56.7 %, 84.1 %, and 79.6 % for the three performance measures, respectively. Also, Tukey&rsquo / s method of mean comparison test is carried out to compare the basic dispatching rules. From the results of statistical analysis, it is concluded that the effects of basic truck dispatching rules on the system performance are not significant. But, the main factors affecting the performances are the number of trucks, the number of shovels, the distance between the shovels and dump site, finally the availability of shovel and truck resources. Also, there are significant interaction effects between these main factors. Finally, an adaptive rule using the standardized utilization of shovels and trucks is developed.
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Jordfelssimulering och modell-validering med PSCAD av ett impedansjordat distributionsnät / Ground fault simulation and model validation with PSCAD of an impedance grounded distribution system

Hällsten, Christoffer January 2015 (has links)
Detta examensarbete har utförts hos Vattenfall Eldistribution på avdelningen Kontroll och Skydd med målsättningen att utforma och utvärdera en nätmodell avsedd för jordslutningssimuleringar i PSCAD. Ombyggnationen från luftledningar till markkablar har medfört att kapacitansen i distributionsnätet ökat, vilket ställer högre krav på jordfelsutrustning och på nätanalyser för att kunna försäkra att en säkerställd frånkoppling kan ske enligt de myndighetskrav som föreligger. Syftet med arbetet har varit att undersöka hur en nätmodell bör utformas för analys av stationära in-svängningsförlopp och utvärdera hur stor noggrannhet som kan förväntas gentemot verkliga jordfelsprov vid felresistanser på främst 3 kΩ och 5 kΩ. Nätmodellen har ut-formats efter ett verkligt impedansjordat mellanspänningsnät med π-länkar i PSCAD och utifrån de nätuppgifter som förekommer i Vattenfalls näthanteringsprogram Netbas. Simuleringsresultaten har jämförts mot resultat från det verkliga nätets jord-felsprover vid olika inställningar på den centrala kompenseringsutrustningen som är placerad mellan den matande transformatorns nollpunkt och jord. Jordslutningssimuleringarna visar, trots antaganden och en viss osäkerhet omkring de verkliga nollföljdskomponenterna, godtyckliga simuleringsresultat vid avstämt och snedavstämt nät motsvarande ± 30 A gentemot ledningarnas kapacitiva strömmar vid en felresistans på 3 kΩ. Jordslutningssimuleringarnas händelseförlopp överensstäm-mer överlag väl mot det verkliga nätet samtidigt som jordslutningar vid 5 kΩ medför en större procentuell avvikelse. Särskilt framträdande avvikelser kunde urskiljas vid analys av fasvinkeln mellan nollföljdsspänning och nollföljdsström. En analys av nätmodellens resultat och troliga orsaker till uppkomna simulerings-avvikelser gentemot det verkliga nätet indikerar på att nätmodellens tillförlitlighet bör kunna optimeras ytterligare om noggrannare hänsyn tas gällande nollföljdsimpedanser, dc-komponenter och de toleranser som förekommer i det verkliga nätets avstäm-ningsutrustning och mätkretsar. / This thesis has been carried out at Vattenfall Eldistribution at the department Control and Protection with the objective to design and evaluate a network model for ground fault simulations in PSCAD. The reconversion from overhead lines to underground cables has led to increased capacitances in the distribution network and this places greater demands on the feeder protection unit and network analyzes in order to assure that faulted feeders are disconnected according to regulatory requirements. The aim of this work has been to determine how a network model could be designed for analysis of stationary signal characteristics and evaluate how great accuracy the power system model have compared to real earth fault test results. Earth fault simulations are performed with fault resistances of 3 kΩ and 5 kΩ. The power system model have been created to emulate a real impedance grounded network according to the π-model in PSCAD based on system information from Vattenfalls network management program Netbas. Results from the simulations have been compared against results obtained from real earth faults from the physical network with different settings on the central compensation equipment placed between the transformers neutral and ground. Simulations show, despite assumptions and some uncertainty about the actual zero sequence components similar results when fault resistance was 3 kΩ, both when compensation coil are fully tuned and out of tune ± 30 A corresponding to the feeder capacitance. The overall signal sequence conform quite well to the real network but at the same time simulations with 5 kΩ obtains greater deviations when results are represented in percentage. Particularly prominent abnormalities could be identified in the phase angle between zero sequence voltage and zero sequence current. An analysis of deviations from the simulations in the digital network model against the real system indicates that the model probably could be further optimized if zero sequence impedances, dc components, and tolerances that occur in the real systems reactive compensation equipment and measuring circuits are taken into account.
79

Biogeodinâmica de herbicidas utilizados em cana-de-açúcar (Saccharum spp.) na sub-bacia do rio Corumbataí / Biogeodynamic of herbicides used in sugarcane (Saccharum spp.) at Corumbataí river watershed

Eduardo Dutra de Armas 28 August 2006 (has links)
A sub-bacia hidrográfica do rio Corumbataí é de grande importância sócioeconômica no estado de São Paulo, cujo rio, de mesmo nome, tornou-se alvo de preocupação ainda maior nos últimos anos, quando passou a atender 100% do abastecimento do município de Piracicaba. Sendo explorada principalmente pela cultura da cana-de-açúcar e composta de solos com características físico-químicas distintas e relevo variando de plano a montanhoso, surge grande preocupação em torno do comportamento ambiental dos agrotóxicos empregados nesta bacia, o qual é desconhecido até o momento. O presente estudo teve por objetivo avaliar a biogeodinâmica dos agrotóxicos empregados em cana-de-açúcar nesta bacia hidrográfica, vindo a servir de subsídio aos processos de avaliação da qualidade da água desta bacia e definição de metas para o Plano de Bacias, elaborado pelo Comitê das Bacias dos Rios Piracicaba, Capivari e Jundiaí. Este trabalho consistiu de caracterização temporal do uso de agrotóxicos em cana-de-açúcar, o qual serviu de suporte na definição de moléculas e períodos de amostragem para o monitoramento de resíduos em água e sedimento na calha principal do rio Corumbataí e principais afluentes. A identificação de áreas críticas na sub-bacia para o aporte de agrotóxicos foi realizada por meio do modelo matemático SWAT. O estudo apontou o uso principalmente de herbicidas, sendo os únicos produtos de uso declarado no período de avaliação, com consumo sazonal de algumas moléculas e uso indistinto de outras ao longo do ano, o que permitiu um planejamento estratégico do monitoramento de resíduos. Os herbicidas glifosato, atrazina, ametrina, 2,4-D, metribuzim, diurom e acetocloro representaram aproximadamente 85% do volume total de produtos consumidos entre 2000 e 2003. Imazapir foi identificado como o herbicida de maior freqüência de uso, sendo também vislumbrado o emprego de moléculas de alta toxicidade e mobilidade, como sulfentrazona, trifloxissulfurom-sódico, paraquate, tebutiurom e imazapique. No monitoramento de resíduos, níveis quantificáveis de ametrina, atrazina, simazina, hexazinona, glifosato e clomazona foram detectados em amostras de água, com níveis desprezíveis de ametrina e glifosato em sedimento. A área de recarga do aqüífero Guarani, no norte da bacia, apresentou os níveis mais elevados de triazinas e clomazona. As triazinas representam o grupo de moléculas detectadas em níveis mais altos, com a atrazina superando os padrões de potabilidade e de qualidade de água para a vida aquática em alguns pontos. Estas moléculas foram também apontadas pela simulação, como as de maior tendência de ocorrer nos corpos hídricos superficiais e subterrâneos, quando aplicadas em período chuvoso, sendo superadas por glifosato em corpos hídricos superficiais, quando a aplicação ocorreu em período de seca. A simulação de um cenário de expansão da cultura de cana-de-açúcar resultou em aumento da participação das áreas com Areia Quartzosa para o aporte de herbicidas aos corpos hídricos, que juntamente com o Podzólico Vermelho-Amarelo, Podzólico Vermelho-Escuro e solos Litólicos, apresentaram maior vulnerabilidade na bacia. As regiões norte da bacia e as sub-bacias do Ribeirão Claro e rio Passa Cinco evidenciaram as maiores exportações de herbicidas aos corpos hídricos e níveis de resíduos em segmentos de rio após o período de chuva intensa. / The Corumbataí river watershed is of great socioeconomic importance in the state of São Paulo, which river, of the same name, became target of higher concern in the last years, when it started to assist 100% the provisioning of the municipal district of Piracicaba. Being explored mainly by the culture of sugarcane and composed of soils with different physicochemical characteristics and relief varying from plan to mountainous, great concern appears around the environmental behavior of pesticides employed in this basin, whose dynamics is ignored until then. The present study had for objective to evaluate the biogeodynamic of pesticides employed in sugarcane in this watershed, coming to serve from subsidy to the water quality evaluation processes of this basin and definition of goals for the Plan of Basins elaborated by the Watersheds Committee of Piracicaba, Capivari, and Jundiaí Rivers. This work consisted of temporal characterization of the use of pesticides on sugarcane, which served as support in the definition of molecules and sampling periods for the residue monitoring in water and sediment in the main channel of the Corumbataí river and main affluents. The identification of critical areas in the sub-basin for the contribution of pesticides was accomplished through the mathematical model SWAT. The study pointed the use mainly of herbicides, being the only one, whose use was declared in the evaluation period, with seasonal consumption of some molecules and use of others along the whole year, what allowed a residue monitoring strategic planning. The herbicides glyphosate, atrazine, ametryne, 2,4-D, metribuzin, diuron and acetochlor represented around 85% of the total volume of products consumed between 2000 and 2003. Imazapyr was identified as the herbicide of larger use frequency, being also observed the use of high toxicity and mobility molecules, as sulfentrazone, trifloxysulfuron-sodium, paraquat, tebuthiuron and imazapic. In the residue monitoring, quantifiable levels of ametryne, atrazine, simazine, hexazinone, glyphosate and clomazone were detected in water samples, with negligible levels of ametryne and glyphosate in sediment. The recharge area of the Guarani aquifer, in the north of the basin, presented the highest levels of triazines and clomazone. The triazines represent the group of molecules detected in higher levels, with the atrazine overcoming the water potability and quality standards for the aquatic life in some points. These molecules were pointed also for the simulation, as the one of larger tendency of happening in the surface waters and groundwaters, when applied in raining periods, being overcome by glyphosate in surface water bodies, when the application happened in dry period. The simulation of a sugarcane culture expansion scenery resulted in increase of the participation of the areas with Typic Quartzipsamment (Areia Quartzosa) for the herbicides contribution to the water bodies, which added with Typic Hapludult (Podzólico Vermelho-Amarelo), Rhodic Kandiudox (Podzólico Vermelho-Escuro) and Typic Udorthent (Litólico) soils, presented larger vulnerability in the basin. The north region of the Corumbataí river watershed and the sub-basins of Ribeirão Claro and Passa Cinco river showed the largest herbicide loadings to water bodies and levels of residues in river segments after the period of intense rain.
80

Influência das técnicas reprodutivas e tipo de acasalamento em programas de seleção de gado de corte e seu impacto no custo e na produção de tourinhos / Influence of the reproductive techniques and the kind of mating in programmes of beef cattle selection, and its impact on the cost and on the young bulls production

Ricardo Carneiro Brumatti 30 June 2006 (has links)
A seleção e produção de touros para o mercado pecuário tornam-se foco de muitos estudos, e um grande desafio para o segmento em se tratando da constante busca de melhorias nos desempenhos produtivos dessa categoria animal. A tese teve por objetivo simular o que poderá acontecer com a produção de reprodutores, em termos de quantidades produzidas e custos operacionais efetivos, sob a influência dos métodos de acasalamentos e das biotécnicas reprodutivas disponíveis no mercado nacional. A hipótese em questão é a de testar se acasalar matrizes, classificadas por genótipo, suas produções serão melhores do que quando comparada à produção de matrizes classificadas por fenótipo. Foram simulados 42 cenários produtivos, divididos em 21 cenários com acasalamento genotípico e 21 com acasalamento fenotípico. Em cada divisão constam simulações com uso de Monta Natural, Inseminação Artificial padrão e com sêmen sexado para machos, Transferência de Embriões padrão e com sêmen sexado para machos, Fecundação in vitro padrão e com sêmen sexado para machos, sendo que em todos os casos três níveis diferentes de taxas de concepção foram testados. Os resultados apontaram que o sistema de acasalamento teve influência direta na produção de tourinhos, sendo que o acasalamento por genótipo foi mais eficiente do que o acasalamento por fenótipo. As taxas de concepção influenciaram negativamente mais os resultados dos sistemas de acasalamento fenotípico. Há um grande aumento no custo operacional efetivo dos sistemas que utilizaram as biotécnicas reprodutivas de Transferência de Embriões e Fecundação in vitro, e consequentemente uma redução na lucratividade destes sistemas. As simulações com Monta Natural apresentaram as maiores Margens Brutas e as simulações com Inseminação Artificial com uso de sêmen sexado para machos apresentaram os maiores Lucros Brutos. / The selection and production of bulls for the cattle market have both become the goal of many studies, as well as a great challenge for the segment, providing the constant search for performance improvement of that sort of animal. The target of this thesis is to simulate what may happen to the production of stud, in terms of quantity and effective operational costs, under the influence of the mating methods and the available reproduction biotechniques in the national market. The hypothesis under analysis consists of testing if mating matrices, classed by their genotype, their produce will be better than when compared to the produce of phenotype-classed matrices. 42 productive-scenes, divided into 21 genotype mating and 21 phenotype mating were simulated. In each of the scene divisions there were the following simulations: Natural Breeding, standard Artificial Insemination, Artificial Insemination with male-gendered semen, standard Embryo Transference, Embryo Transference with male-gendered semen, standard In-vitro Fecundation and In-vitro Fecundation with male-gendered semen, so that in all the cases, three different conception rates were tested. The results displayed that the mating system directly influenced the young bull production, once the genotype mating was more efficient than the phenotype mating. The conception rates negatively influenced the results of the phenotype mating mainly. There was a dramatic increase in the effective operational cost of the systems that used the reproductive biotechniques of Embryo Transference and In-vitro Fecundation, and, consequently, profitability reduction of those systems. The Natural Breeding simulations presented the highest Gross Margin, and the simulations of Artificial Insemination with male-gendered semen showed the highest Gross Profit.

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