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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.
131

The New Generation Spacecraft Data Simulator to Test Level Zero Processing Systems

Michandani, Chandru, Kozlowski, Chuck, Bennett, Toby 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / Over the last several years, the Data Systems Technology Division (DSTD) at Goddard Space Flight Center (GSFC) has developed software tools to generate simulated spacecraft data to support the development, test, and verification of prototype and production of its Very Large Scale Integration (VLSI) telemetry data systems. Recently, these data simulation tools have demonstrated their versatility and flexibility in the testing and deployment of several very high performance Level Zero Processing (LZP) systems. Because LZP involves the wide scale reordering of transmitted telemetry data, the data simulation tools were required to create a number of very large and complex simulated data sets to effectively test these high rate systems. These data sets simulated spacecraft with numerous instrument data sources downlinking out-of-sequence and errored data streams. Simulated data streams were encapsulated in Consultative Committee for Space Data Systems (CCSDS) packet and NASCOM data formats. The knowledge and expertise gained in the development of the current simulation tools has been used to develop a new generation data simulation tool, known as the Simulated Telemetry Generation (STGEN) package. STGEN is a menu driven software package running on UNIX platforms that can implement dynamic test scenarios with very fast turn around times from the data set design to the data set generation. The error options and locations in the telemetry data stream are fed via simple programs which are in turn script-driven. Scripts are used to manipulate packets, frames, and permit error insertion more easily and quickly. This paper first describes the STGEN software package and its test data design strategies. It then provides an example of STGEN 's first usage in the testing of systems to support EOS-AM spacecraft. Finally, a description of future planned improvements and uses of STGEN are provided.
132

Localising imbalance faults in rotating machinery

Walker, Ryan January 2013 (has links)
This thesis presents a novel method of locating imbalance faults in rotating machinery through the study of bearing nonlinearities. Localisation in this work is presented as determining which discs/segments of a complex machine are affected with an imbalance fault. The novel method enables accurate localisation to be achieved using a single accelerometer, and is valid for both sub and super-critical machine operations in the presence of misalignment and rub faults. The development of the novel system for imbalance localisation has been driven by the desire for improved maintenance procedures, along with the increased requirement for Integrated Vehicle Health Management (IVHM) systems for rotating machinery in industry. Imbalance faults are of particular interest to aircraft engine manufacturers such as Rolls Royce plc, where such faults still result in undesired downtime of machinery. Existing methods of imbalance localisation have yet to see widespread implementation in IVHM and Engine Health Monitoring (EHM) systems, providing the motivation for undertaking this project. The imbalance localisation system described has been developed primarily for a lab-based Machine Fault Simulator (MFS), with validation and verification performed on two additional test rigs. Physics based simulations have been used in order to develop and validate the system. An Artificial Neural Network (ANN) has been applied for the purposes of reasoning, using nonlinear features in the frequency domain originating from bearing nonlinearities. The system has been widely tested in a range of situations, including in the presence of misalignment and rub faults and on a full scale aircraft engine model. The novel system for imbalance localisation has been used as the basis for a methodology aimed at localising common faults in future IVHM systems, with the aim of communicating the results and findings of this research for the benefit of future research. The works contained herein therefore contribute to scientific knowledge in the field of IVHM for rotating machinery.
133

Visualisering för spelbaserat lärande

Trikilis, Efrosini, Nyberg Hamrén, Johanna January 2014 (has links)
Denna undersökande designstudie utforskar hur visuellt material till en simulator kan komma att se ut och hur vägen fram till det färdiga designen kan se ut. Simulatorn som står i centrum för just denna studie kallas för Simulerade Provokationer (SimProv) och har lärarstudenter som huvudsaklig målgrupp. I SimProv kan lärarstudenten som användare välja mellan fyra olika handlingar i en klassrumssituation. Klassrumssituationerna är baserade på händelser som lärare i svenska skolan dagligen kan möta. Det visuella materialet skapas för att illustrera handlingsalternativen och i största möjliga mån få med lärarens känslor och tankar. Litteraturgenomgången tar upp ledarskap, kroppsspråk och visualisering. Genom förstudie, skisser och utvärdering tas ett visuellt material fram baserat på både tidigare forskning och utforskande design.
134

Business jet safety and accident study

Sears, R. W. 08 1900 (has links)
As world transport has grown in complexity, so has public pressure for safe flight. The scheduled airline industry has a consistently good safety record. Unfortunately, the business jet industry has not kept pace with the airline safety statistics and lags far behind. During safety surveys and reports over the past 5 years there has been increasing comment and concern over the perceived safety standards of business jets operations compared with normal scheduled airline services. The UK Civil Aviation Authority (CAA) has reported that based on flight hours flown, the fatal accident rate for smaller jet aircraft below 15 tonnes was twice that for large passenger aircraft (CAA 2006a). The CAA also identified that the majority of the accidents occur during the approach and landing phase of the flight. There is however, a lack of research concerning business jet operations. Due to the unique and varied style of operations, business jet flights have many factors that differentiate it from normal scheduled airline operations. Business jet accidents have been reported but they have not been further investigated for any overall causes. The study described in this thesis, a Grounded Theory analysis of accident data was conducted to develop a model of the factors that contributed to the accidents. The model that was developed demonstrated that Pilot skills, Command and Crew Resource management are the key central elements, with the ground organisations such as engineering and ground operations personnel as a contributory influence. As piloting skills were determined as a key factor in the accident statistics and the accident model, a simulator trial was also conducted to assess the manual flying skill levels of business jet pilots. The trial was both a challenging manual flying task and a profile that is included as part of the Pilot Skill test prior to the issue of a commercial pilot’s licence. The simulator trial confirmed that although all the pilots were correctly tested and certified commercial pilots, a significant proportion did not fly an accurate airspeed on approach within the CAA examination tolerances. The simulator trial data and the grounded theory model found that there are concerns for the piloting skills of business jet pilots in their ability to fly an accurate airspeed on approach. The results from this investigation yield findings concerning the piloting skill and accuracy of the business jet pilots that had not previously been identified. The results also emphasise the need to include adequate testing and supervision during business jet operations. It is recommended that further research be conducted to evaluate actual piloting skill and accuracy during the licence skill test.
135

Wireless system design : NB-IoT downlink simulator

Krasowski, Piotr, Troha, Douglas January 2017 (has links)
The newly defined NB-IoT standard currently lacks a toolkit and simulator. In order to develop algorithms for this new standard there is a need for channels and signals as reference during tests. MATLAB is commonly used for testing LTE signals and therefore the toolkit was developed in this environment. The toolkit focuses primarily on the Layer 1-relevant functionality of NB-IoT, the grid generation, encoding, rate-matching and modulation of channels. The simulator focuses on testing the developed toolkit in a virtual LTE NB-IoT environment. The virtual environment attempts to emulate a base station and a terminal. The path followed is scheduling, channel processing, grid generation, QPSK and OFDM modulation through a modeled channel, OFDM demodulation, channel estimation, equalisation, QPSK demodulation and reversal of channel processing. The simulator tests primarily the NPDSCH channel implementations. Measurements of bit error and block error rates were made and it was concluded that they follow the expected trends. More testing is required to validate the remaining channels. A sector equaliser and an interpolating equaliser were tested by measuring block error rate and checking constellation diagrams and it was concluded that the performance of the interpolation equaliser is more consistent. In order to improve the equalisation further the noise estimation must be reworked.
136

OpenFlow Switching Performance using Network Simulator - 3

Sriram Prashanth, Naguru January 2016 (has links)
Context. In the present network inventive world, there is a quick expansion of switches and protocols, which are used to cope up with the increase in customer requirement in the networking. With increasing demand for higher bandwidths and lower latency and to meet these requirements new network paths are introduced. To reduce network load in present switching network, development of new innovative switching is required. These required results can be achieved by Software Define Network or Traditional layer-3 technologies.Objectives. In this thesis, the end to end (e2e) transmission performance of OpenFlow and Layer-3 switches and their dynamic characteristics are investigated using network simulation.Methods. To replicate real life network topology and evaluate e2e transmission performance, a simulation based test-bed is implemented for both OpenFlow switch and layer-3 switch. The test beds are implemented using Network Simulator-3 (NS3). A two-tire network topology is designed with specified components for performance evaluation.Results. The performance metrics like throughput, average delay, simulation time and Packet Delivery Ratio (PDR) are measured, results are analyzed statistically and are compared. The behavior of network traffic in both the topologies are understood using NS-3 and explained further in the thesis.Conclusions. The analytical and statistical results from simulation show that OpenFlow switching performs relatively better than layer-3 switching.
137

Sistema simulador del sonar de los submarinos. Una aplicación para la Marina de Guerra del Perú

Arias Bailly, Bruno January 2008 (has links)
In this Thesis work the development of a Software Simulation that allows closest offer at training to the reality for sonar operator’s personal in formation and described System sets out; with the objective to present the operability on board to Sonar device of the submarine units, as well as interaction with existing simulation modules inside the simulator Attack of Submarine Force of the Navy military of Peru, Located at the Submarine School. The Thesis is divided in four parts: the Introduction to the proposed subject and its problematic; Theoretical Frame that corresponds to variables that include the reach of this work; the State of the Art where a case in individual of a Sonar Simulator Software constructed under another programming language is exposed, which does not have similarity with electronic equipment sonar on board of the submarine units; finally the exposition of a development proposal, improvement and execution of a sonar simulator software that fulfills the functionality of the original electronic equipment on board. The hypothesis is in demonstrating that it’s possible to develop a sonar simulator software that allows to carry out functionalities of the original electronic equipment. Proven this throughout the Thesis, the objective is obtained: to demonstrate that it’s possible to construct a sonar simulator software that shows the contacts, generate the noise corresponding, sent the data necessary to other simulation modules, and simulating the Test containing in the original equipment. / En este trabajo de Tesis se propone el desarrollo de un Software de Simulación que permita brindar un entrenamiento más cercano a la realidad al personal de sonaristas en formación y calificado; con el objetivo de dar a conocer la operabilidad del sonar integrado a bordo de las unidades submarinas, así como la interacción con los módulos de simulación existentes en simulador de ataque de la Fuerza de Submarinos de la Marina de Guerra del Perú, ubicado en la Escuela de Submarinos. La Tesis se divide en cuatro partes: la Introducción al tema propuesto y su problemática; el Marco Teórico que corresponde a las variables que engloban el alcance de este trabajo; el Estado del Arte donde se expone un caso en particular de un software de simulación de sonar desarrollado bajo otro lenguaje de programación, el cual no tiene similitud con el sonar existente a bordo de las unidades submarinas; finalmente el planteamiento de una propuesta de desarrollo, mejoramiento y ejecución de un sistema simulador de sonar que cumpla con las funcionalidades del equipo de a bordo y se integre al sistema de simulación existente. La hipótesis está en demostrar que es posible desarrollar un software de simulación del sonar que permita realizar las funcionalidades que contiene el equipo original. Probado esto a lo largo de la Tesis, se logra el objetivo: demostrar que es posible construir un software simulador de sonar que muestra los contactos, genere el ruido sintético de las hélices, envié los datos necesarios a los otros módulos de simulación, y simule las pruebas Test que contiene el equipo original.
138

Dimensionamento operacional e econômico da colheita mecanizada de cana-de-açúcar (Saccharum ssp): modelo computacional como ferramenta de apoio a tomadas de decisão / Operational and economical dimensioning of mechanized sugarcane (Saccharum spp) harvest: computational model as a support tool for decision making

Rosa, João Henrique Mantellatto 20 March 2017 (has links)
O sistema de colheita de cana-de-açúcar representa a conexão entre o campo e a indústria no complexo sucroenergético, exigindo uma sinergia operacional entre os agentes envolvidos. Sob a ótica econômica, é um dos principais, senão o principal, dispêndio da cadeia agroindustrial de produção de açúcar e etanol. Considerando o número de variáveis envolvidas, as diferentes naturezas das mesmas e as relações interdependentes observadas, seu gerenciamento é complexo, exigindo uma análise sistêmica. Nesse sentido, os modelos computacionais podem ser aplicados como ferramenta de gestão, permitindo o conhecimento prévio do desempenho dos sistemas e a possibilidade de desenvolver cenários para testar situações de interesse. Sendo assim, o objetivo deste trabalho foi o desenvolvimento de um modelo em Excel® para o dimensionamento operacional e econômico de um sistema mecanizado de colheita de cana-de-açúcar, contemplando os subsistemas de corte, transbordo, transporte e apoio e suas interrelações. Para a validação e a verificação do modelo utilizou-se de dados obtidos juntos a um condominio agrícola, além de comparações com indicadores publicados na bibliografia. Com base nos resultados, afirma-se que o modelo pode ser utilizado como uma ferramenta de apoio em tomadas de decisão relacionadas ao sistema mecanizado de colheita. / The sugarcane harvesting system represents the connection between the field and the industry in the sugar-energy industry, demanding operational synergy between the involved agents. Under the economic point of view, it is one of the main, or indeed the main, expenditure of agroindustrial production chain of sugarcane and ethanol. Considering the number of variables involved, the different natures and the interdependent relationships observed, its management is complex, requiring a systemic analysis. In this matter, the computational models can be applied as a management tool, allowing prior knowledge of the systems performances and the possibility of developing scenarios in order to test situations of interest. Therefore, the aim of this study was de development of an Excel® model for the operational and economic design of a mechanical sugarcane harvesting system, contemplating the cutting subsystems, carry, transport and support and their interrelationships. For validation and verification of the model, data from real sources were used, obtained along with an agricultural condominium, besides comparisons with indicators published in the bibliography. Based on the results, the model can be used as a tool for decision-making related to mechanical sugarcane harvesting system.
139

Design aplicado em simulação de anestesia infiltrativa bloqueio do nervo alveolar inferior / Applied design in simulation of infiltrative anesthesia block of inferior alveolar nerve

Paccola, Sileide Aparecida de Oliveira 24 February 2014 (has links)
Esta pesquisa apresenta a pesquisa e desenvolvimento da interface gráfica Objetos Virtuais 3D, do Simulador de Bloqueio do Nervo Alveolar Inferior, destinado ao ensino na graduação. O objetivo deste trabalho foi desenvolver os modelos tridimensionais reais - 3DR, por meio de modelagem das camadas de tecidos da cabeça, equivalente a apresentada pelo público infantil na faixa etária dos 07 aos 12 anos, considerando as características físicas e reais inerentes de cada tecido (tecidos moles, músculos, nervos e ossos), para demonstrar de forma realística a anatomia da face e da boca, com a visualização das camadas de tecidos presentes nessa região, a fim de proporcionar ao aluno um ambiente virtual 3D rico para imersão, envolvimento e interação. O projeto previu o desenvolvimento dos objetos virtuais 3D, integrando as etapas de pesquisa teórica, modelagem tridimensional das camadas de tecidos da cabeça e modelagem das texturas realísticas para construção do ambiente virtual realístico. Em virtude de envolver conhecimento de múltiplas áreas Design, Odontologia e Sistemas Digitais, esta pesquisa teve caráter multidisciplinar. A revisão sistemática foi realizada a fim de verificar a relevância da tecnologia de realidade aumentada (RA) no ensino da odontologia. Seus resultados mostraram que há uma evolução rápida e importante quanto ao uso de tecnologias de RA e RV no ensino na área da saúde de forma geral, e em particular na odontologia, principalmente para simulação de procedimentos cirúrgicos. O processo de trabalho se dividiu em etapas de modelagem dos objetos na ordem: crânio, tecidos moles, músculos, veias e nervos. O crânio foi desenvolvido tendo como base referencial um arquivo de ressonância magnética de uma criança de idade aproximada de 10 anos. Para a modelagem dos dentes foram utilizados modelos tridimensionais em resina, além do conhecimento publicado na literatura, orientações de professores da Faculdade de Odontologia - FOB/USP, e de técnicos do laboratório de anatomia. A literatura e as orientações dos professores e técnicos foram as referências para as modelagens dos tecidos moles, músculos, veias e nervos. A modelagem das texturas de sobreposição das estruturas modeladas, teve como objetivo atribuir o máximo de realismo às mesmas. Desta forma, foram utilizados como referências, além da literatura, imagens que mostram a cavidade bucal em situações variadas, para observar os aspectos realísticos de cada estrutura. Foram realizados testes de estereoscopia, por meio da geração de imagens estereoscópicas, para observar o desempenho do modelo 3DR, quanto ao seu realismo na visualização em 3D. Os resultados finais apresentados mostraram um alto grau de complexidade e realismo dos modelos 3DR. / This research presents the research and development of graphical user interface - 3D virtual objects, from the inferior alveolar block anesthesia simulator, for teaching undergraduate students. The objective of this study was to develop virtual models 3DR through modeling the layers of head tissue, similar to the children between the ages of 07 to 12 years, considering the physical and real inherent characteristics of each tissue (soft tissues, muscles, nerves and bones), to realistically demonstrate the anatomy of the face and mouth, with the visualization of tissue layers in the region cited, in order to provide the student with a rich 3D virtual environment immersion, engagement and interaction. The project included the development of 3D virtual objects by integrating the steps of theoretical research, three-dimensional modeling of the tissue layers of the head, and the modeling of realistic textures for the construction of realistic virtual environment. Since it comprises knowledge from multiple areas - Design, Dentistry and Digital Systems, this research was multidisciplinary. A systematic review was performed to check the relevance of augmented reality (AR) technology in the teaching of dentistry. The results showed a rapid and important development regarding the use of AR and VR (virtual reality), technologies in education in the health field in general, and in particular in dentistry, especially for simulation of surgical procedures. The work process is divided into stages modeling of objects in order: skull, soft tissue, muscles, veins and nerves. The skull was developed using as reference based on a file MRI (Magnetic Resonance Image) of a child aged approximately 10 years. For modeling three-dimensional models of the teeth were used in resin, besides the knowledge published in the literature, anesthesia guidelines from Pediatric Dentist of Bauru School of Dentistry University of Sao Paulo, and the anatomy lab technicians. The literature and guidelines teachers and technicians were references to the modeling of soft tissues, muscles, veins and nerves. Modeling textures overlay of patterned structures, aimed to allocate the maximum realism to them. Thus images were used as references, besides the literature, showing the oral cavity in various situations, to observe the realistic aspects of each structure. Stereoscopy tests were conducted by generating stereoscopic images to observe the performance of the model 3DR, as to its realism in the 3D view. The final results showed a high degree of complexity and realism of the model 3DR.
140

Simulačně orientované DSS pro různé úrovně řízení / Simulation oriented DSS for different levels of management

Kaděra, Vladimír January 2011 (has links)
This thesis is dealing with using of simulation modeling as a support for decision making in different control level. Theoretic analysis of that problem covers and summarized information about modeling and simulation as well as importance of knowledge of simulation models and systems for decision making provision. Case study which illustrates possibilities using of Arena simulation software for needs decision making on operative control level and a software product Powersim Studio for needs higher control levels is a part of this thesis. Simulations were performed with particular software models and their results were summarized and evaluated by a selecting method of specific variant of solution.

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