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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.
261

A generic predictive information system for resource planning and optimisation

Tavakoli, Siamak January 2010 (has links)
The purpose of this research work is to demonstrate the feasibility of creating a quick response decision platform for middle management in industry. It utilises the strengths of current, but more importantly creates a leap forward in the theory and practice of Supervisory and Data Acquisition (SCADA) systems and Discrete Event Simulation and Modelling (DESM). The proposed research platform uses real-time data and creates an automatic platform for real-time and predictive system analysis, giving current and ahead of time information on the performance of the system in an efficient manner. Data acquisition as the backend connection of data integration system to the shop floor faces both hardware and software challenges for coping with large scale real-time data collection. Limited scope of SCADA systems does not make them suitable candidates for this. Cost effectiveness, complexity, and efficiency-orientation of proprietary solutions leave space for more challenge. A Flexible Data Input Layer Architecture (FDILA) is proposed to address generic data integration platform so a multitude of data sources can be connected to the data processing unit. The efficiency of the proposed integration architecture lies in decentralising and distributing services between different layers. A novel Sensitivity Analysis (SA) method called EvenTracker is proposed as an effective tool to measure the importance and priority of inputs to the system. The EvenTracker method is introduced to deal with the complexity systems in real-time. The approach takes advantage of event-based definition of data involved in process flow. The underpinning logic behind EvenTracker SA method is capturing the cause-effect relationships between triggers (input variables) and events (output variables) at a specified period of time determined by an expert. The approach does not require estimating data distribution of any kind. Neither the performance model requires execution beyond the real-time. The proposed EvenTracker sensitivity analysis method has the lowest computational complexity compared with other popular sensitivity analysis methods. For proof of concept, a three tier data integration system was designed and developed by using National Instruments’ LabVIEW programming language, Rockwell Automation’s Arena simulation and modelling software, and OPC data communication software. A laboratory-based conveyor system with 29 sensors was installed to simulate a typical shop floor production line. In addition, EvenTracker SA method has been implemented on the data extracted from 28 sensors of one manufacturing line in a real factory. The experiment has resulted 14% of the input variables to be unimportant for evaluation of model outputs. The method proved a time efficiency gain of 52% on the analysis of filtered system when unimportant input variables were not sampled anymore. The EvenTracker SA method compared to Entropy-based SA technique, as the only other method that can be used for real-time purposes, is quicker, more accurate and less computationally burdensome. Additionally, theoretic estimation of computational complexity of SA methods based on both structural complexity and energy-time analysis resulted in favour of the efficiency of the proposed EvenTracker SA method. Both laboratory and factory-based experiments demonstrated flexibility and efficiency of the proposed solution.
262

A cross-layer middleware architecture for time and safety critical applications in MANETs

Pease, Sarogini G. January 2013 (has links)
Mobile Ad hoc Networks (MANETs) can be deployed instantaneously and adaptively, making them highly suitable to military, medical and disaster-response scenarios. Using real-time applications for provision of instantaneous and dependable communications, media streaming, and device control in these scenarios is a growing research field. Realising timing requirements in packet delivery is essential to safety-critical real-time applications that are both delay- and loss-sensitive. Safety of these applications is compromised by packet loss, both on the network and by the applications themselves that will drop packets exceeding delay bounds. However, the provision of this required Quality of Service (QoS) must overcome issues relating to the lack of reliable existing infrastructure, conservation of safety-certified functionality. It must also overcome issues relating to the layer-2 dynamics with causal factors including hidden transmitters and fading channels. This thesis proposes that bounded maximum delay and safety-critical application support can be achieved by using cross-layer middleware. Such an approach benefits from the use of established protocols without requiring modifications to safety-certified ones. This research proposes ROAM: a novel, adaptive and scalable cross-layer Real-time Optimising Ad hoc Middleware framework for the provision and maintenance of performance guarantees in self-configuring MANETs. The ROAM framework is designed to be scalable to new optimisers and MANET protocols and requires no modifications of protocol functionality. Four original contributions are proposed: (1) ROAM, a middleware entity abstracts information from the protocol stack using application programming interfaces (APIs) and that implements optimisers to monitor and autonomously tune conditions at protocol layers in response to dynamic network conditions. The cross-layer approach is MANET protocol generic, using minimal imposition on the protocol stack, without protocol modification requirements. (2) A horizontal handoff optimiser that responds to time-varying link quality to ensure optimal and most robust channel usage. (3) A distributed contention reduction optimiser that reduces channel contention and related delay, in response to detection of the presence of a hidden transmitter. (4) A feasibility evaluation of the ROAM architecture to bound maximum delay and jitter in a comprehensive range of ns2-MIRACLE simulation scenarios that demonstrate independence from the key causes of network dynamics: application setting and MANET configuration; including mobility or topology. Experimental results show that ROAM can constrain end-to-end delay, jitter and packet loss, to support real-time applications with critical timing requirements.
263

GPU-Based Visualisation of Viewshed from Roads or Areas in a 3D Environment

Christoph, Heilmair January 2016 (has links)
Viewshed refers to the calculation and visualisation of what part of a terrain isvisible from a given observer point. It is used within many fields, such as militaryplanning or telecommunication tower placement. So far, no general fast methodsexist for calculating the viewshed for multiple observers that may for instancerepresent a road within the terrain. Additionally, if the terrain contains over-lapping structures such as man-made constructions like bridges, most currentviewshed algorithms fail. This report describes two novel methods for viewshedcalculation using multiple observers for terrain that may contain overlappingstructures. The methods have been developed at Vricon in Linköping as a Mas-ter’s Thesis project. Both methods are implemented using the graphics program-ming unit and the OpenGL graphics library, using a computer graphics approach.Results are presented in the form of figures and images, as well as running timetables using two different test setups. Lastly, future possible improvements arealso discussed. The results show that the first method is a viable real-time solu-tion and that the second method requires some additional work.
264

An error recovery technique for real-time distributed computer systems

Bloch, Gerald 12 August 2016 (has links)
A Thesis Submitted to the Faculty 0/ Engineering, University 0/ Lite Witwatersrand, Johannesburg in fulfilment 0/ the requirements /01' the Degree 0/ Doctor 0/ Philosophy. Johannesburg 1990. / This thesis studies fault tolerant strategies for real-time distributed computer control systems so as to propose an error recovery technique that renders individual processors on the network resistant to soft failures. The technique is effective for soft failures which have as certain maximum duration, and does not require the use of specialised hardware. Attention is focused on achieving resistance to soft failures in environments which have demanding time constraints such as those found in computer systems for process control, materials handling and automated manufacturing. [Abbreviated Abstract. Open document to view full version]
265

A real-time expert system shell for process control.

Kang, Alan Montzy January 1990 (has links)
A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering / A multi-layered expert system shell that specifically addresses real-time issues is designed and implemented. The architecture of this expert system shell supports the concepts of parallelism, concurrent computation and competitive reasoning in that it allows several alternatives to be explored simultaneously. An inference engine driven by a hybrid of forward and backward chanining methods is used to achieve real-time response, and certainty factors are used for uncertainty management. Real-time responsiveness is improved by allowing the coexistence of procedural and declarative knowledge within the same system. A test bed that was set up in order to investigate the performance of the implemented shell is described. It was found in the performance analysis that the proposed system meets the real-time requirements as specified in this research. / Andrew Chakane 2018
266

Emprego da reação em cadeia pela polimerase em tempo real para o controle de eficiência de bacterinas anti-leptospirose / Employment of real time polymerase chain reaction to control the efficiency of leptospirosis bacterins

Dib, Cristina Corsi 31 August 2011 (has links)
A estirpe Fromm de Leptospira interrogans sorovar Kennewicki foi utilizada para produção de uma bacterina experimental anti-leptospirose. A extração do RNA total utilizado para transcrição reversa e quantificação dos antígenos LigA e LipL32 por PCR em Tempo Real, foi efetuada a partir de alíquotas colhidas das diluições da bacterina antes da sua inativação, as quais foram armazenadas à temperatura de -80ºC. O volume restante da bacterina foi inativado em banho-maria à 56ºC e mantido à temperatura de -20ºC para avaliação da sua potência em hamsters bem como da detecção e quantificação dos antígenos LigA e LipL32 em ensaios de ELISA Indireto e ELISA Sanduíche Indireto. Os resultados do ensaio de potência em hamsters demonstraram que a bacterina foi aprovada de acordo com as exigências dos padrões internacionais de qualidade até a diluição 1/6400, protegendo os hamters contra a infecção letal frente ao desafio com a diluição 10-6 (100 doses infectantes 50%/ 0,2mL). Os resultados das reações de Real Time PCR detectaram 3,2 x 103 e 2,3 x 101 cópias do mRNA que codifica a proteína LigA, na bacterina pura e diluída a 1:200, respectivamente. Apenas oito cópias do mRNA que codifica a proteína LipL32 foram detectadas na amostra de bacterina pura. Os ensaios com ELISA Indireto não detectaram a proteína LigA na amostra de bacterina inativada, mas demonstraram a detecção da proteína LipL32 até a diluição 1/1600 da bacterina. Os ensaios de ELISA Sanduíche Indireto apresentaram reações cruzadas nas placas controle, e, portanto seus resultados não puderam ser considerados nas análises. Os resultados da real time PCR não puderam ser correlacionados com o teste de potência em hamsters, mas os ensaios de ELISA Indireto para a proteína LipL32 demonstraram resultados condizentes com os apresentados pelo teste de potência em hamsters oferecendo uma possível alternativa in vitro para avaliação de potência de bacterinas anti-leptospirose. / Leptospira interrogans serovar Kennewicki strain Fromm was used for the production of a experimental leptospirosis bacterin. The extraction of total RNA used for reverse transcription and quantification of the antigens LigA and LipL32 for Real Time PCR was performed from the aliquots harvested of bacterin dilutions before inactivation that were separated and maintained at -80ºC. The remaining volume of bacterin was inativated at 56ºC and maintained at -20ºC for the evaluation bacterin potency in hamsters and detection and quantification of LigA and LipL32 antigens by Indirect ELISA assay and Indirect Sandwich ELISA. The results of potency assay in hamsters demonstrated that the bacterin was approved by the international patterns of quality until dilution 1/6400, protecting the hamters against lethal infection challenge by the dilution 10-6 (100 infectious doses 50%/0,2 mL). The results of Real Time PCR detected 3,2 x 103 e 2,3 x 101 copies of mRNA that encodes the LigA protein, in samples of pure bacterin and diluted 1:200, respectively. Few eight copies of mRNA that encodes LipL32 protein were detected in pure bacterin samples. Indirect ELISA assays not detected LigA protein in inactivated bacterin samples, but demonstrated LipL32 protein detection until dilution 1:1600 of bacterin. Indirect Sandwich ELISA presented cross-reaction in control plates, so the results cannot be considerated in the analysis. The results of real time PCR cannot be correlated with the potency assay in hamsters but Indirect ELISA assay for protein LipL32 demonstrated that the results were suitable with the results presented by the potency assay in hamsters offering a possible in vitro alternative for the evaluation of leptospirosis bacterins potency.
267

Realistic hair rendering in Autodesk Maya / Realistic hair rendering in Autodesk Maya

Svoboda, Tomáš January 2012 (has links)
This thesis describes a real-time hair rendering in 3D animation and modeling software Autodesk Maya. The renderer is part of the Stubble project a - Maya plug-in for hair modeling. The presented renderer provides a high-quality interactive preview that allows fast hair modeling without the need for rendering in slow off-line renderers. The goal of this work is to create a renderer that can generate images in real-time that are as close as possible to the output of the 3Delight renderer - a plug-in for Maya that is based on RenderMan standards.
268

Emprego da reação em cadeia pela polimerase em tempo real para o controle de eficiência de bacterinas anti-leptospirose / Employment of real time polymerase chain reaction to control the efficiency of leptospirosis bacterins

Cristina Corsi Dib 31 August 2011 (has links)
A estirpe Fromm de Leptospira interrogans sorovar Kennewicki foi utilizada para produção de uma bacterina experimental anti-leptospirose. A extração do RNA total utilizado para transcrição reversa e quantificação dos antígenos LigA e LipL32 por PCR em Tempo Real, foi efetuada a partir de alíquotas colhidas das diluições da bacterina antes da sua inativação, as quais foram armazenadas à temperatura de -80ºC. O volume restante da bacterina foi inativado em banho-maria à 56ºC e mantido à temperatura de -20ºC para avaliação da sua potência em hamsters bem como da detecção e quantificação dos antígenos LigA e LipL32 em ensaios de ELISA Indireto e ELISA Sanduíche Indireto. Os resultados do ensaio de potência em hamsters demonstraram que a bacterina foi aprovada de acordo com as exigências dos padrões internacionais de qualidade até a diluição 1/6400, protegendo os hamters contra a infecção letal frente ao desafio com a diluição 10-6 (100 doses infectantes 50%/ 0,2mL). Os resultados das reações de Real Time PCR detectaram 3,2 x 103 e 2,3 x 101 cópias do mRNA que codifica a proteína LigA, na bacterina pura e diluída a 1:200, respectivamente. Apenas oito cópias do mRNA que codifica a proteína LipL32 foram detectadas na amostra de bacterina pura. Os ensaios com ELISA Indireto não detectaram a proteína LigA na amostra de bacterina inativada, mas demonstraram a detecção da proteína LipL32 até a diluição 1/1600 da bacterina. Os ensaios de ELISA Sanduíche Indireto apresentaram reações cruzadas nas placas controle, e, portanto seus resultados não puderam ser considerados nas análises. Os resultados da real time PCR não puderam ser correlacionados com o teste de potência em hamsters, mas os ensaios de ELISA Indireto para a proteína LipL32 demonstraram resultados condizentes com os apresentados pelo teste de potência em hamsters oferecendo uma possível alternativa in vitro para avaliação de potência de bacterinas anti-leptospirose. / Leptospira interrogans serovar Kennewicki strain Fromm was used for the production of a experimental leptospirosis bacterin. The extraction of total RNA used for reverse transcription and quantification of the antigens LigA and LipL32 for Real Time PCR was performed from the aliquots harvested of bacterin dilutions before inactivation that were separated and maintained at -80ºC. The remaining volume of bacterin was inativated at 56ºC and maintained at -20ºC for the evaluation bacterin potency in hamsters and detection and quantification of LigA and LipL32 antigens by Indirect ELISA assay and Indirect Sandwich ELISA. The results of potency assay in hamsters demonstrated that the bacterin was approved by the international patterns of quality until dilution 1/6400, protecting the hamters against lethal infection challenge by the dilution 10-6 (100 infectious doses 50%/0,2 mL). The results of Real Time PCR detected 3,2 x 103 e 2,3 x 101 copies of mRNA that encodes the LigA protein, in samples of pure bacterin and diluted 1:200, respectively. Few eight copies of mRNA that encodes LipL32 protein were detected in pure bacterin samples. Indirect ELISA assays not detected LigA protein in inactivated bacterin samples, but demonstrated LipL32 protein detection until dilution 1:1600 of bacterin. Indirect Sandwich ELISA presented cross-reaction in control plates, so the results cannot be considerated in the analysis. The results of real time PCR cannot be correlated with the potency assay in hamsters but Indirect ELISA assay for protein LipL32 demonstrated that the results were suitable with the results presented by the potency assay in hamsters offering a possible in vitro alternative for the evaluation of leptospirosis bacterins potency.
269

Hybrid adaptive controller for resource allocation of real-rate multimedia applications

Vahia, Varin 01 April 2003 (has links)
Multimedia applications such as video streaming and Voice over IP are becoming common today with the tremendous growth of the Internet. General purpose operating systems thus are required to support these applications. These multimedia applications have some timing constraints that need to be satisfied for good quality. For example, video streaming applications require that each video frame be decoded in time to be displayed every 33.3 milliseconds. In order to satisfy these timing requirements, general purpose operating systems need to have fine-grained scheduling. Current general purpose operating systems unfortunately are designed to maximize throughput to serve traditional data-oriented applications and have coarse-grained scheduling and timers. Time Sensitive Linux (TSL), designed by Goel, et al., solves this problem with fine-grained timers and schedulers. The scheduler for TSL is implemented at a very low level. The controller that implements the algorithm for resource allocation is implemented at a higher level. This controller can easily be modified to implement new control algorithms. Successful implementation of resource allocation to satisfy timing constraints of multimedia applications requires two problems to be addressed. First, the resources required by the application to satisfy the timing constraints should not exceed the total available resources in the system. Second, the controller must adapt to changing needs of the applications and allocate enough resources to satisfy the timing constraints of each application over time. The first problem has been addressed elsewhere using intelligent data dropping with TSL. We focus on the second problem in this thesis. We design a proportion-period controller in this thesis for allocating CPU to multimedia video applications with timing constraints. The challenges for the controller design include the coarse granularity of the time-stamp markings of the video frames, the unpredictable decoding completion times of the frames, the large variations in the decoding times of the frames, and the limit of the control actuation to positive values. We set up the problem in a state space. We design a predictive estimating controller to allocate the proportion of the CPU to a thread when its long term error is small. When the decoding process is running behind by more than a certain threshold, we switch to a different controller to drive the error back to a small value. This controller is the solution to a dynamic optimization LQR tracking problem. / Graduation date: 2003
270

Management of Real-Time Data Consistency and Transient Overloads in Embedded Systems

Gustafsson, Thomas January 2007 (has links)
This thesis addresses the issues of data management in embedded systems' software. The complexity of developing and maintaining software has increased over the years due to increased availability of resources, e.g., more powerful CPUs and larger memories, as more functionality can be accommodated using these resources. In this thesis, it is proposed that part of the increasing complexity can be addressed by using a real-time database since data management is one constituent of software in embedded systems. This thesis investigates which functionality a real-time database should have in order to be suitable for embedded software that control an external environment. We use an engine control software as a case study of an embedded system. The findings are that a real-time database should have support for keeping data items up-todate, providing snapshots of values, i.e., the values are derived from the same system state, and overload handling. Algorithms are developed for each one of these functionalities and implemented in a real-time database for embedded systems. Performance evaluations are conducted using the database implementation. The evaluations show that the real-time performance is improved by utilizing the added functionality. Moreover, two algorithms for examining whether the system may become overloaded are also outlined; one algorithm for off-line use and the second algorithm for on-line use. Evaluations show the algorithms are accurate and fast and can be used for embedded systems.

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