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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.
311

Dynamic Memory Management for Embedded Real-Time Multiprocessor System-on-a-Chip

Shalan, Mohamed A. 25 November 2003 (has links)
The aggressive evolution of the semiconductor industry smaller process geometries, higher densities, and greater chip complexity has provided design engineers the means to create complex, high-performance System-on-a-Chip (SoC) designs. Such SoC designs typically have more than one processor and huge (tens of Mega Bytes) amount of memory, all on the same chip. Dealing with the global on-chip memory allocation/deallocation in a dynamic yet deterministic way is an important issue for upcoming billion transistor multiprocessor SoC designs. To achieve this, we propose a memory management hierarchy we call Two-Level Memory Management. To implement this memory management scheme which presents a shift in the way designers look at on-chip dynamic memory allocation we present the System-on-a-Chip Dynamic Memory Management Unit (SoCDMMU) for allocation of the global on-chip memory, which we refer to as Level Two memory management (Level One is the management of memory allocated to a particular on-chip Processing Element, e.g., an operating systems management of memory allocated to a particular processor). In this way, processing elements (heterogeneous or non-heterogeneous hardware or software) in an SoC can request and be granted portions of the global memory in a fast and deterministic time. A new tool is introduced to generate a custom optimized version of the SoCDMMU hardware. Also, a real-time operating system is modified support the new proposed SoCDMMU. We show an example where shared memory multiprocessor SoC that employs the Two-Level Memory Management and utilizes the SoCDMMU has an overall average speedup in application transition time as well as normal execution time.
312

A Modeling Methodology for Automotive Embedded System¡GAn MDA Approach with UML

Lin, Chia-Chun 11 July 2012 (has links)
Automotive embedded systems used much in the main body control system. Also because the system needs to meet functional requirement, environment requirement, timing requirement, interface requirement and Failure Mode and Effects Analysis (FMEA) so it is necessary to have an automotive embedded systems modeling methodology. Therefore, this study proposes an automotive embedded systems modeling methodology which combines MDA and UML, and detailed description of the model diagram used by each modeling phase and the diagram modeling method and steps. System development team can be clearly implemented in accordance with the methods and steps for automotive embedded system modeling. The methodology also can be used as the communication standard of the system development team. Systems modeling during system modular can promote module reuse rate in order to enhance the efficiency of system development. The methodology of this study is based on design science research methods, usability evaluation of the modeling methodology is implemented for the modeling of demand for Parking aid control unit, the PIM modeling and code conversion. With prove the availability of this modeling methodology. From the results of the assessment system development team can be based on the methodology of modeling methods and procedures to express the results in line with the needs and systems analysis and design of automotive embedded systems and convert the system operating platform and code.
313

Innovative Design Methodology of Automatic Transmissions with Embedded Clutches for Automobiles

Lin, Chih-Yang 10 September 2012 (has links)
Hyundai, Toyota and GM automobile factory were committed to provide more speed planetary gear automatic transmission research and development in order to improve the transmission performance and fuel efficiency. To set embedded clutch into planetary gear mechanism is an effective way to get more speed ratio, its call an epicyclic-type automatic transmission with embedded clutches, referred to the embedded-type automatic transmission. For the development of automatic transmission with eight or more speed ratios, an efficient design methodology is urgently needed and still not available. Therefore, the purpose of this article is to develop a systematic method for the design of automatic transmission with embedded clutches. First, the features and requirements of the automatic transmissions with embedded clutches are investigated and the corresponding design requirements are induced. Next, the theory of the analysis of kinematic for automatic transmissions with embedded clutches is derived based on the concept of lever analogy. Then, the design theory of automatic transmissions with embedded clutches is developed based on the analysis theory. Finally, the complete atlas of automatic transmissions with embedded clutches can be systematically synthesized from the data of given speed ratios. In this article, the innovative and patentable seven-speed and eight-speed automatic transmissions with embedded clutches have been done. This proposed design method can also be applied to the development and design of ten-speed automatic transmissions with embedded clutches.
314

On the Porting of Qt/Embedded and Its Integration with OpenGL ES

Tsai, Wen-Chia 10 February 2006 (has links)
¡@¡@An embedded system has improved quickly in recent years and now functions like a small computer. Equipped with operating systems (OS), graphic user interfaces (GUI), and software developed for various platforms, an embedded system provides users with services more powerful and friendlier than ever. Qt/Embedded and OpenGL ES are an OS and a GUI developed for embedded systems. In this thesis, We integrated Qt/Embedded with OpenGL ES on a Versatile PB 92EJ-S and conducted various tests. ¡@¡@The Versatile PB 92EJ-S was equipped with ARM926EJ-S, an onboard chip capable of performing VFP9 vector floating operation. However, not all embedded systems are powered by a floating coprocessor. To make the test results applicable to all systems, We performed only fixed-point operations, a practice also improving the overall performance. In addition, to provide communications between OpenGL ES and Windows and interfaces for OpenGL ES to draw, We implemented EGL, a platform interface layer defined in OpenGL ES. Furthermore, We developed GLUT ES, a modification of GLUT, to make the embedded system compatible with Windows of different versions. Finally, We benchmarked the platform with programs developed by GLUT ES interfaces and OpenGL ES.
315

Efficient Handling of Narrow Width and Streaming Data in Embedded Applications

Li, Bengu January 2006 (has links)
Embedded environment imposes severe constraints of system resources on embedded applications. Performance, memory footprint, and power consumption are critical factors for embedded applications. Meanwhile, the data in embedded applications demonstrate unique properties. More specifically, narrow width data are data representable in considerably fewer bits than in one word, which nevertheless occupy an entire register or memory word and streaming data are the input data processed by an application sequentially, which stay in the system for a short duration and thus exhibit little data locality. Narrow width and streaming data affect the efficiency of register, cache, and memory and must be taken into account when optimizing for performance, memory footprint, and power consumption.This dissertation proposes methods to efficiently handle narrow width and streaming data in embedded applications. Quantitative measurements of narrow width and streaming data are performed to provide guidance for optimizations. Novel architectural features and associated compiler algorithms are developed. To efficiently handle narrow width data in registers, two register allocation schemes are proposed for the ARM processor to allocate two narrow width variables to one register. A static scheme exploits maximum bitwidth. A speculative scheme further exploits dynamic bitwidth. Both result in reduced spill cost and performance improvement. To efficiently handle narrow width data in memory, a memory layout method is proposed to coalesce multiple narrow width data in one memory location in a DSP processor, leading to fewer explicit address calculations. This method improves performance and shrinks memory footprint. To efficiently handle streaming data in network processor, two cache mechanisms are proposed to enable the reuse of data and computation. The slack created is further transformed into reduction in energy consumption through a fetch gating mechanism.
316

HUMIDITY SENSOR CIRCUIT USING REAL TIME OPERATING SYSTEM (FREERTOS) KERNEL

Chen, Bojie 01 January 2014 (has links)
A humidity sensor can be used to measure the moisture content of the environment. The physical change of the sensor expresses as the change of electrical property like capacitance, resistance, voltage, current, frequency, etc. In order to process these analog signals digitally, microprocessor is involved in the measurement. This thesis presents design of a circuit to measure low moisture levels. The 16-bit RISC mixed signal microcontroller MSP430F249 from Texas Instruments will be used. The circuit has good performance at extremely low humidity levels. Meanwhile, a small real time operating system kernel FreeRTOS, a market leading RTOS from Real Time Engineer Ltd is ported to the microcontroller. The basic concept about FreeRTOS and how to port this RTOS to MSP430F249 microcontrollers will be the topics of this thesis as well.
317

Forced simulation : a formal approach to component based development of embedded systems /

Roop, Parthasarathi. January 2000 (has links)
Thesis (Ph. D.)--University of New South Wales, 2000. / Addenda sheet inserted. Includes bibliographic references. Also available online.
318

Evaluation of code generation in agile software development of embedded systems

D'Angelo, Laura January 2018 (has links)
Generating code from software models is considered to be a new generation leap within software development methods. The objective of this M.Sc. project is to evaluate how different approaches to modelling and code generation affect embedded systems software development and propose recommendations on how to improve software development. Two product areas at Saab Surveillance EW Systems in Järfälla, Stockholm, are used as study objects. A research overview is made to highlight themes regarding modelling, code generation and software development in general. Based on these, interviews are held with system engineers and software developers at each product area, where they use different modelling and code generation approaches. The two development processes are described thoroughly. Challenges and advantages related to each area’s approach are investigated. Software development within product area A is affected by the product complexity and the larger scale of the development, including projects running over a longer time with more teams involved. Recommendations include enabling code generation by aligning it with other investments on process improvement and limiting the approach to generating some system components. Software developers within product area B can use full code generation, enabled by the limited product complexity. The product area is affected by software standards and external requirements on the process. Recommendations include extending the modelling approach to make it easier to trace functionality from system to software level. Conclusions are that both product areas can apply modelling and code generation to more software development activities to improve their respective development processes.
319

A state-based method to model and analyze the power consumption of embedded systems

Haulin, Lars January 2018 (has links)
In this work I have evaluated a method to model, measure and analyze the power consumption of embedded systems. The method combines current measurement with debug trace data telling which parts of the systems that are enabled. This makes it possible to compute the individual current consumption of the parts in the system from a single measurement point. The method allows an embedded systems engineer to determine the power consumption of individual parts in a system to either get an overview or to compare several revisions of hardware and/or software with each other. The method also captures the system dynamics of the power delivery route. This makes the model consumption behave more like the actual system around state transitions. The case study is focused on the Arm-based microcontroller CC2650 from Texas Instruments and uses the I-scope/I-jet probe from IAR Systems to measure current consumption and collect trace data.
320

Metodologia de projeto de software embarcado voltada ao teste

Gomes, Humberto Vargas January 2010 (has links)
Devido ao crescente incremento de complexidade do software embarcado atual, dada a abundância de recursos disponíveis de hardware, está cada vez mais difícil manter a qualidade do software embarcado desenvolvido sem incorrer em aumentos de custo que inviabilizem o projeto. Com isto, o teste de software embarcado é atualmente uma importante área de pesquisa, onde são buscadas técnicas de teste que maximizem o número de falhas encontradas ainda em tempo de projeto e a um custo satisfatório. Muitas das soluções pesquisadas envolvem aspectos não apenas relativos ao teste propriamente dito, mas ao projeto do produto desde a sua concepção, daí a necessidade de metodologias conjuntas de desenvolvimento e teste. Neste trabalho, é apresentada uma metodologia de desenvolvimento e testes de software embarcado com o objetivo de permitir que grande parte da tarefa de desenvolvimento e teste seja executada em um ambiente de desenvolvimento de software de aplicação, sem a presença do hardware. Neste ambiente, o desenvolvimento é pensado desde o início do projeto visando à qualidade do teste, assim caracterizando esta metodologia como uma técnica DFT (do inglês design for testability). Na abordagem proposta, o hardware físico é substituído por modelos funcionais, construídos na mesma linguagem de programação do software em desenvolvimento. O uso destes modelos permite ao desenvolvedor a construção e aplicação de casos de teste capazes de exercitar o software embarcado tanto no ambiente de software de aplicação, quanto na plataforma alvo, sem alterações. Esta dissertação mostra a metodologia sendo aplicada ao software embarcado de um medidor eletrônico de energia, onde cinco modelos de dispositivos de hardware foram construídos, que permitiram a execução tanto de testes de unidade, quanto de testes de integração, em um ambiente de desenvolvimento de software de aplicação. Finalmente, uma análise de cobertura, realizada com o auxílio de uma ferramenta que, de outra forma, não seria compatível com o software da plataforma alvo, mostrou que a execução conjunta do software e dos modelos permite atingir a cobertura de quase a totalidade do software embarcado desenvolvido, onde os casos de teste foram capazes de verificar desde as camadas de software de aplicação até as camadas de software dependente do hardware. / Due to the growing increment of complexity of the current embedded software, given the abundance of hardware resources, it is becoming increasingly difficult to maintain the software quality without requiring high development and test costs that could make the project impracticable. In this context, embedded software testing is an important research area, where test techniques that maximize the number of errors detected during design time at a satisfactory cost have been investigated. Many of the proposed solutions involve aspects not related only to the testing itself, but to the product design since its conception, hence the need of methodologies for the development and test of software. In this work, we present a methodology of development and test of embedded software that allows the execution of most of the task of development and test in an application software development environment, without the physical hardware. In the application software environment, the development is thought, since the first stages, aiming the execution of the test, hence this methodology can be seen as a DFT (design for testability) technique. In the proposed approach, the physical hardware is replaced by functional models, constructed using the same programming language of the embedded software under development. The use of such models allows the developer to construct and apply test cases capable of exercising the embedded software both in the application software environment and in the target platform environment, without any change. In this work, the presented methodology is applied to the embedded software of an electronic energy meter, where five hardware device models were constructed, which enabled the execution of both unit and integration tests in the application software environment. Finally, the coverage analysis, performed with a software tool that otherwise would not be compatible with the target platform, showed that the simultaneous execution of the software and the models make it possible to achieve an almost complete coverage of the developed embedded software, where the test cases were able to verify the software from the application layers to the hardware dependent layers.

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