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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.
1

SYSTEM IDENTIFICATION OF A WASTE-FIRED CFB BOILER : Using Principal Component Analysis (PCA) and Partial Least Squares Regression modeling (PLS-R)

Hassling, Andreas, Flink, Simon January 2017 (has links)
Heat and electricity production along with waste management are two modern day challenges for society. One of the possible solution to both of them is the incineration of household waste to produce heat and electricity. Incineration is a waste-to-energy treatment process, which can reduce the need for landfills and save the use of more valuable fuels, thereby conserving natural resources. This report/paper investigates the performance and emissions of a municipal solid waste (MSW) fueled industrial boiler by performing a system identification analysis using Principle Component Analysis (PCA) and Partial Least Squares Regression (PLS-R) modeling. The boiler is located in Västerås, Sweden and has a maximum capacity of 167MW. It produces heat and electricity for the city of Västerås and is operated by Mälarenergi AB. A dataset containing 148 different boilers variables, measured with a one hour interval over 2 years, was used for the system identification analysis. The dataset was visually inspected to remove obvious outliers before beginning the analysis using a multivariate data analysis software called The Unscrambler X (Version 10.3, CAMO Software, Norway). Correlations found using PCA was taken in account during the PLSR modelling where models were created for one response each. Some variables had an unexpected impact on the models while others were fully logical regarding combustion theory. Results found during the system analysis process are regarded as reliable. Any errors may be due to outlier data points and model inadequacies.
2

Analýza přechodů vedení v pásmech milimetrových vln / Analysis of planar junction in millimeter bands

Ambros, Martin January 2013 (has links)
This diploma thesis solves possibilities of transitions between waveguides and hybrid types of integrated microwave circuits. It describes the basic ways of solutions this transitions in both longitudinal and transverse as well. In thesis is also mentioned the principle of SIW technology, which is in this transitions widely used. The practical part is focused on the modeling and analysis of selected structures in CST MW Studio. Modeled structures are optimized for the lowest possible value insertion loss transition and are adapted to the characteristic impedance on 50. Selected structures are recalculated to a lower frequency band, realized and results of their simulation verified by measurements.
3

Šroubovicová dvoupásmová anténa pro WiFi pásmo / Dual-Band Helix Antenna for WiFi band

Šrajbr, Michal January 2012 (has links)
This master’s thesis is focused on the properties and types of helical antennas. The helical antenna work in the different modes. These modes are described in this thesis. There are also discussed possibility for design a dual-band helical antennas. The main aim of this work is the selection of a suitable solution and design a dual-band helical antenna for the WiFi band working at resonance frequencies of 2,4 GHz and 5 GHz. The simulation of this antenna was performed in the program CST Microwave studio.
4

L'algorithmique au lycée entre développement de savoirs spécifiques et usage dans différents domaines mathématiques / Algorithmics in high school between development of specific knowledge and use in various mathematical domains

Laval, Dominique 08 March 2018 (has links)
Les nouveaux programmes des lycées français, mis en place depuis la rentrée 2010, ont fixé des objectifs précis en matière d’algorithmique. A la lecture de ces programmes, l’enseignement de l’algorithmique apparaît comme outil (au sens de Douady, 1986) pour donner sens à un certain nombre de notions étudiées. Comment dépasser ce stade pour que l’algorithmique devienne objet d’apprentissage (au sens de Douady, 1986) ? Le travail de recherche se situe dans le cadre d’apprentissages de connaissances sur les algorithmes en mathématiques dans l’enseignement au niveau des classes de Seconde et du Cycle Terminal Scientifique du lycée. L’étude et la construction d’algorithmes par les élèves sont situées dans un cadre plus général de raisonnement et de preuve, mais aussi de démarches de modélisation en mathématiques. Il s’agit d’étudier l’effectivité de tels enseignements dans le cadre institutionnel français du point de vue des apprentissages effectivement réalisés par les élèves et des pratiques des enseignants, et d’en inférer des résultats plus généraux sur le raisonnement mathématique dans certains domaines spécifiques, pour les classes du lycée. Le travail de recherche entrepris privilégie la place occupée par les algorithmes dans l’enseignement des mathématiques et propose un cadre théorique tenant compte des cadres généraux de la didactique des mathématiques, en particulier les Espaces de Travail Mathématique (ETM) (Kuzniak, Richard, 2014) associés à des domaines mathématiques spécifiques. Plus particulièrement, poursuivant la spécification d’un modèle Espaces de Travail Algorithmique (ETA) (Laval, 2014, 2016), nous précisons ce que peuvent être les plans épistémologique et cognitif dans ces espaces en mettant l’accent sur leurs interactions liées aux genèses sémiotique, instrumentale et discursive auxquelles ces plans donnent lieu. Nous étudions aussi quels espaces personnels peuvent se construire chez les élèves des différents niveaux scolaires du lycée, et comment ils articulent des connaissances sur les algorithmes et les domaines mathématiques scolaires. Les modèles des ETM/ETA sont consacrés à l’analyse du travail mathématique dans des domaines mathématiques spécifiques avec, en particulier, des paradigmes guidant et orientant le travail des élèves. De plus, partant du fait que peu d’études sur des tâches de modélisation ont été basées sur les modèles ETM/ETA, nous affinons certaines de nos analyses dans le cadre des ETM/ETA sur la base du cycle de modélisation proposé par Blum et Leiss (2005) en relation avec certains domaines spécifiques des mathématiques. Pour cela, nous construisons plusieurs ingénieries didactiques mettant en place des expérimentations dans trois domaines mathématiques : (1) la théorie élémentaire des nombres ; (2) l’analyse ; (3) les probabilités et les simulations aléatoires. Ces ingénieries sont expérimentées et analysées dans les trois niveaux du lycée français : seconde et cycle terminal scientifique. Notre travail de recherche comporte des outils d’analyse de tâches et d’activités dans différents domaines mathématiques. La méthodologie employée permet d’obtenir des données globales et d’observer finement les activités des élèves en classe et les pratiques des enseignants / The new programs of French High schools, since 2010, precise objectives in terms of algorithmics. According to High schools curricula, algorithmics teaching appears as a tool (in the sense of Douady, 1986) to give meaning to some studied notions. How to go beyond this level so that algorithmic becomes an object of learning (in the sense of Douady, 1986)? This research work is in the framework of learning of mathematical knowledge in algorithmics at the level of Grade 10 and Scientific Terminal Cycle (Grades 11 and 12) of the French high school. The study and construction of algorithms by students are located in a more general framework of reasoning and proof, but also mathematical modelling. We build three didactic engineerings in High school to study the work of student and to watch teacher’s practices. Our aim is to infer more general results on mathematical reasoning in some specific mathematical domains.The research work favours algorithms’ place in mathematics teaching. We propose a theoretical framework taking into account the general frameworks of mathematics didactics, in particular the Mathematical Working Spaces (MWS) (Kuzniak, Richard, 2014) associated with specific mathematical domains.Following the specification of an Algorithmics Working Spaces (AWS) (Laval, 2014, 2016) we specify the possibilities of the epistemological and cognitive plans inside of these spaces increasing their interactions with their semiotician, instrumental and discursive geneses. We also study which personal spaces can be built for students at different levels of High school system, and how they articulate knowledge about algorithms and school mathematical domains. The models of MWS/AWS aim at analysing of mathematical work in specific mathematical domains, with in particular, paradigms guiding and directing the work of the student.Moreover, since few studies of modelling tasks have been built on MWS/AWS models, we refined some our analyses in the framework MWS/AWS basing on the modelling cycle proposed by Blum & Leiss (2005) in relation to some specific mathematical domains.We build several didactic engineerings that we experimented in various mathematical domains: (1) elementary number theory; (2) mathematical analysis; (3) probabilities and random simulations. These didactic engineerings are experimented and analysed in various French High school's grade: Grade 10 and Scientific Terminal Cycle (Grades 11 and 12). Our research work includes tools for analysing tasks and activities in different mathematical domains. The methodology obtains aggregated global data and finely observes students' activities in classroom and teacher’s practices
5

Rekonfigurovatelná štěrbinová anténní řada / Reconfigurable slot antenna array

Weigel, Filip January 2016 (has links)
This master's thesis deals with the basic principles of slot antennas. Models of antennas were simulated in a selected electromagnetic simulator CST MICROWAVE STUDIO (CST MWS). There are several models of slot antennas which are optimized for communication in the car at a frequency 8 GHz.
6

Antena indoor de dupla polarização para recepção de TV digital

Santos, Guilherme Boscolo dos 30 January 2018 (has links)
Submitted by Marta Toyoda (1144061@mackenzie.br) on 2018-03-09T16:59:58Z No. of bitstreams: 2 GUILHERME BOSCOLO DOS SANTOS.pdf: 18400225 bytes, checksum: 47dbfd4bd3d74984f6d4c7bfff9e594d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Paola Damato (repositorio@mackenzie.br) on 2018-04-04T11:41:38Z (GMT) No. of bitstreams: 2 GUILHERME BOSCOLO DOS SANTOS.pdf: 18400225 bytes, checksum: 47dbfd4bd3d74984f6d4c7bfff9e594d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-04-04T11:41:38Z (GMT). No. of bitstreams: 2 GUILHERME BOSCOLO DOS SANTOS.pdf: 18400225 bytes, checksum: 47dbfd4bd3d74984f6d4c7bfff9e594d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-01-30 / With the establishment of digital television technology, improvements have emerged com- pared to analogue, such as bringing users better quality picture and video. This transition of the analogue/digital system is already a reality in Brazil, so that organs linked to the Brazilian government are performing the process of switch-off the analogue signal. This switch-off aims to release the electromagnetic spectrum in the UHF band to allow the expansion of mobile broadband. Due to this operation in adjacent bands, there is a pos- sibility that the LTE signal interferes with digital TV. Studies presented by researchers report that antennas designed with ”smart” characteristics can reduce interference from unwanted signals. When designed with dual polarization, such antennas enable the wireless link to become more robust due to differences polarization existing between the transmitter and the receiver of the current communications systems. This essay presents a new pro- posal of dual-polarized antenna, whose operating is destined to the radio frequency range of the digital television after the switch-off, so that it can be used in the current digital te- levision standard as in the next-generation of digital broadcasting. The proposed antenna was designed with a full wave electromagnetic field simulator. A prototype was simulated and built and experimental results showed that the proposed antenna could cover a band of 384 MHz in the UHF band and 40 MHz in the high VHF band as well as serving as a filter for the LTE band. Tests were performed using software defined radio and showed their reception quality. / Com o estabelecimento da tecnologia da televisão digital, melhorias surgiram comparadas com à analógica, como levar aos usuários uma melhor qualidade de imagem e vídeo. Essa transição do sistema analógico/digital já é uma realidade no Brasil, de modo que órgãos ligados ao governo brasileiro já estão realizando o processo de desligamento do sinal analógico. Esse desligamento que tem por objetivo liberar o espectro eletromagnético na faixa de UHF para permitir a expansão da banda larga móvel. Devido a esta operação em faixas adjacentes, existe a possibilidade do sinal LTE interferir na TV digital. Estudos apresentados por pesquisadores relatam que antenas projetadas com características de “inteligentes” podem reduzir interferências vindas de sinais indesejáveis. Quando projetadas com dupla polarização, tais antenas ainda possibilitam que o enlace sem fio se torne mais robusto frente às diferenças de polarização existentes entre o transmissor e o receptor dos sistemas de comunicações atuais. Esta pesquisa apresenta uma nova proposta de antena com dupla polarização, cuja faixa de operação é destinada a faixa de radiofrequência da televisão digital após o desligamento do sinal analógico, de forma a ser utilizada no atual sistema de televisão como em sua próxima geração. A antena proposta foi projetada com simulador de campo eletromagnético de onda completa. Um protótipo foi simulado e construído e os resultados experimentais demonstraram que a antena proposta pode cobrir uma banda de 384 MHz na faixa do UHF e 40 MHz na de VHF alto além de servir como filtro para a faixa do LTE. Testes foram realizados utilizando rádio definidos por software e mostraram sua qualidade de recepção.

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