Browsing by Subject "Embedded systems"
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Item Dynamic time management for improved accuracy and speed in host-compiled multi-core platform models(2014-05) Razaghi, Parisa; Gerstlauer, Andreas, 1970-With increasing complexity and software content, modern embedded platforms employ a heterogeneous mix of multi-core processors along with hardware accelerators in order to provide high performance in limited power budgets. Due to complex interactions and highly dynamic behavior, static analysis of real-time performance and other constraints is challenging. As an alternative, full-system simulations have been widely accepted by designers. With traditional approaches being either slow or inaccurate, so-called host-compiled simulators have recently emerged as a solution for rapid evaluation of complete systems at early design stages. In such approaches, a faster simulation is achieved by natively executing application code at the source level, abstracting execution behavior of target platforms, and thus increasing simulation granularity. However, most existing host-compiled simulators often focus on application behavior only while neglecting effects of hardware/software interactions and associated speed and accuracy tradeoffs in platform modeling. In this dissertation, we focus on host-compiled operating system (OS) and processor modeling techniques, and we introduce novel dynamic timing model management approaches that efficiently improve both accuracy and speed of such models via automatically calibrating the simulation granularity. The contributions of this dissertation are twofold: We first establish an infrastructure for efficient host-compiled multi-core platform simulation by developing (a) abstract models of both real-time OSs and processors that replicate timing-accurate hardware/software interactions and enable full-system co-simulation, and (b) quantitative and analytical studies of host-compiled simulation principles to analyze error bounds and investigate possible improvements. Building on this infrastructure, we further propose specific techniques for improving accuracy and speed tradeoffs in host-compiled simulation by developing (c) an automatic timing granularity adjustment technique based on dynamically observing system state to control the simulation, (d) an out-of-order cache hierarchy modeling approach to efficiently reorder memory access behavior in the presence of temporal decoupling, and (e) a synchronized timing model to align platform threads to run efficiently in parallel simulation. Results as applied to industrial-strength platforms confirm that by providing careful abstractions and dynamic timing management, our models can achieve full-system simulations at equivalent speeds of more than a thousand MIPS with less than 3% timing error. Coupled with the capability to easily adjust simulation parameters and configurations, this demonstrates the benefits of our platform models for early application development and exploration.Item ExtractCFG : a framework to enable accurate timing back annotation of C language source code(2011-08) Goswami, Arindam; Gerstlauer, Andreas, 1970-; Valvano, Jonathan W.The current trend in embedded systems design is to move the initial design and exploration phase to a higher level of abstraction, in order to tackle the rapidly increasing complexity of embedded systems. One approach of abstracting software development from the low level platform details is host- compiled simulation. Characteristics of the target platform are represented in a host-compiled simulation model by annotating the high level source code. Compiler optimizations make accurate annotation of the code a challenging task. In this thesis, we describe an approach to enable correct back-annotation of C code at the basic block level, while taking compiler optimizations into account.Item Mocking embedded hardware for software validation(2016-08) Kim, Steve Seunghwan; Khurshid, Sarfraz; Bard, WilliamThis report makes the case for unit testing embedded systems software, a procedure traditionally found in application software development. While the challenges of developing and executing unit tests on embedded software are acknowledged, multiple solutions are presented. The GNU toolchain and a Texas Instruments microcontroller are used as an example embedded target. Two applications, one introductory and one more realistic, were developed for this embedded target using the C programming language. This report details the procedure required to apply open-source frameworks, Unity and CMock, to the two embedded applications. These frameworks, combined with the techniques outlined in this report, accomplished several goals of unit testing. The goals included automated validation of the embedded applications, increased code coverage, and protection against regression defects. In addition, it is shown how unit tests led to more modular software architecture. Potential ideas to extend this research to other tools, environments, and frameworks are also discussed.Item Multicast networks : capacity, algorithms, and implementation(2011-12) Abdel Hadi, Ahmed Mohamed; Gerstlauer, Andreas, 1970-; Vishwanath, Sriram; Valvano, Jonathan; Vikalo, Haris; Akella, Maruthi; Bovik, AlanIn this dissertation, we investigate the capacity and performance of wireless networks with an emphasis on multicast traffic. The defining characteristic of a multicast network is a network where a number of different destinations all require the information generated by a single source. The models that we explore differ in the nature of the nodes from all-mobile case where all nodes are mobile to hybrid case where some nodes are mobile and some are static. We investigate different performance measure for these wireless multicast networks: upper bounds, capacity scaling laws, and achievable rates. The understanding of these measures for such networks helps in the development of efficient algorithms for operating these networks. In addition, we study the practical realization of algorithms for real-time streaming of rich multimedia content in the context of mobile wireless networks for embedded and cyberphysical systems. Our initial work is in the context of unicast and multiple unicast systems over an autonomous aerial vehicle (AAV) network. Bandwidth requirements and stringent delay constraints of real-time video streaming, paired with limitations on computational complexity and power consumptions imposed by the underlying implementation platform, make cross-layer and cross-domain co-design approaches a necessity. In this dissertation, we propose a novel, low-complexity rate-distortion optimized (RDO) protocol specifically targeted at video streaming over mobile embedded networks. First, we test the performance of our RDO algorithm on simulation models developed for aerial mobility of multiple wirelessly communicating AAVs. Second, we test the performance of our RDO algorithm and other proposed adaptive algorithms on a real network of AAVs and present a comparative study between these different algorithms. Note that generalizing these algorithms to multicast settings is relatively straightforward and thus is not highlighted to a great degree in this thesis.Item Multichannel digital voltmeter using the LM3S8962 evaluation board(2016-08) Muckelroy, Callie Edward; Valvano, Jonathan W., 1953-; Bard, William Carl, 1944-This project is a proof of concept and prototype in both hardware and software, which demonstrates a useful and flexible 4-channel voltmeter using an LM3S8962 Evaluation Board, and commodity electronic components to serve as a shield circuit. The shield circuit protects the evaluation board from over/under voltage damage, and biases the incoming voltages to provide usable input voltages for the LM3S8962 ADC inputs. The report begins with an explanation of the goals of the project, and research of what current products exist on the commercial market to meet the needs of multichannel voltage measurement. In the interest of cost savings, and in the interest of an academic exploration of the capabilities of the inexpensive evaluation boards on the market, the author explores how the ADC inputs of the LM3S8962 can serve some of the same needs of much more expensive commercial products in voltage measurement. Several obstacles were encountered in the design and construction stages. A description of the obstacles, and how they were overcome is described. The end design of both the shield circuit and software is then detailed end-to-end, along with an explanation of how to use the end product. Finally, the accuracy of the project is assessed and demonstrated.Item Park hunt : an optimized approach to implement and deploy parking monitoring systems in open environments(2011-12) Siddiqui, Fahd Murtuza; Julien, Christine; Aziz, AdnanThe time consuming, tedious, and, sometimes, never ending search for a parking spot is a matter of common experience. We present an innovative approach to parking monitoring systems that only requires sensors at the entry and exit points of a street segment in an open environment such as a city downtown (as opposed to a closed environment such as a parking garage/lot). It can be trivially understood that using this set-up we can determine the number of vehicles present in a given street segment at any given time. However, the bigger issue is to closely estimate how many of those vehicles are parked or en route. We present an algorithm by which we can have a practical estimate of parked cars without introducing any more sensors. We further present a self-stabilizing system that can be implemented for fault tolerance and a few other methods to mitigate errors that may accrue over time. Our approach is based on the assumption that drivers do not care about the exact location of the parking spot, as long as they know the “street segment” where parking is available. For example, just letting the users know of available parking on 7th street between Red River and Brazos gives them enough information to easily find a parking spot. This type of information would most likely be shown on a map. Once the driver reaches the correct street area, it is easy to locate an empty parking spot. Finally, to test and evaluate our approach, we developed and deployed an embedded system using ultra-sonic sensors, and a Microsoft Bing Map application with the said user interface, along with an interoperable web service that can provide parking information to any third party application.Item A phone application to provide advanced remote control functionality to an embedded systems product(2010-08) Michel, Larry Ashley; Khurshid, Sarfraz; Julien, ChristineWith the increasing popularity of phone application development, a number of features have surfaced that enable users to utilize extended functionalities with their phone. With a single device, a user is now able to have access to the latest trends. As a result, functionalities from various products such as personal computers or GPS devices can now be accessible in one place. While this technology is evolving at a fast rate, it is the embedded technology and hardware that drive it which facilitate the innovative designs and solutions. At the other end of the spectrum of embedded systems, companies continue to maintain legacy products that use embedded chips programmed through their flash memory. With this perceived commitment to stay loyal to their older product designs, it has become rather cumbersome for such companies to stay current with the latest hardware and software trends. The result is higher costs to the customers for their high-end products. While the average user invests in newer and faster Google phones or iPhones, it is unlikely that the same can be said for commercial products such as a refrigerator or a ball machine. What if a development framework existed that allowed customers to have access to better user interfaces and functionalities over the lifetime of their product? In this Masters report, an innovative approach is discussed which demonstrates the latest mobile phone technology combined with an existing embedded device being applied to the conversion of a low-end tennis ball machine into an affordable high-end one.