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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.
81

Security and Control System for fluid in a tank

Kvist, Johan January 2007 (has links)
This rapport describes how a security and control system has been developed for moveable diesel tanks. Enormous amounts of diesel in Sweden are stolen every year and the tank that is most vulnerable is the moveable tank in other words tanks that can be moved around with diesel inside. The report proposes methods how to measure fluid amount in a tank and how to measure if diesel is disappearing from the tank. The report also describes a tank monitoring system prototype.
82

Compiler Support for Long-life, Low-overhead Intermittent Computation on Energy Harvesting Flash-based Devices

Ahmad, Saim 19 May 2021 (has links)
With the advent of energy harvesters, supporting fast and efficient computation on energy harvesting devices has become a key challenge in the field of energy harvesting on ubiquitous devices. Computation on energy harvesting devices is equivalent to spreading the execution time of a lasting application over short, frequent cycles of power. However, we must ensure that results obtained from intermittently executing an application do produce results that are congruent to those produced by executing the application on a device with a continuous source of power. The current state-of-the-art systems that enable intermittent computation on energy harvesters make use of novel compiler analysis techniques as well as on-board hardware on devices to measure the energy remaining for useful computation. However, currently available programming models, which mostly target devices with FRAM as the NVM, would cause failure on devices that employ the Flash as primary NVM, thereby resulting in a non-universal solution that is restricted by the choice of NVM. This is primarily the result of the Flash's limited read/write endurance. This research aims to contribute to the world of energy harvesting devices by providing solutions that would enable intermittent computation regardless of the choice of NVM on a device by utilizing only the SRAM to save state and perform computation. Utilizing the SRAM further reduces run-time overhead as SRAM reads/writes are less costlier than NVM reads/writes. Our proposed solutions rely on programmer-guidance and compiler analysis to correct and efficient intermittent computation. We then extend our system to provide a complete compiler-based solution without programmer intervention. Our system is able to run applications that would otherwise render any device with Flash as NVM useless in a matter of hours. / Master of Science / As batteries continue to take up space and make small-scale sensors hefty, battery-less devices have grown increasingly popular for non-resource intensive computations. From tracking air pressure in vehicle tires to monitoring room temperature, battery-less devices have countless applications in various walks of life. These devices function by periodically harvesting energy from the environment and its surroundings to power short bursts of computation. When device energy levels reach a lower-bound threshold these devices must power off to scavenge useful energy from the environment to further perform short bursts of computation. Usually, energy harvesting devices draw power from solar, thermal or RF energy. This vastly depends on the build of the device, also known as a microprocessor (a processing unit built to perform small-scale computations). Due to these devices constantly powering on and off, performing continuous computation on such devices is rather more difficult when compared to systems with a continuous source of power. Since applications can require more time to complete than one power cycle of such devices, by default, applications running on these devices will restart execution from the beginning at the start of every power cycle. Therefore, it is necessary for such devices to have mechanisms to remember where the were before the device lost power. The past decade has seen many solutions proposed to aid an application in restarting execution rather than recomputing everything from the beginning. Solutions utilize different categories of devices with different storage technologies as well different software and hardware utilities available to programmers in this domain. In this research, we propose two different low-overhead, long-life computation models to support intermittent computation on a subset of energy harvesting devices which use Flash-based memory to store persistent data. Our approaches are heavily dependent on programmer guidance and different program analysis techniques to sustain computation across power cycles.
83

Secure Intermittent Computing: Precomputation and Implementation

Suslowicz, Charles Eugene 22 May 2018 (has links)
This thesis explores the security of intermittent devices, embedded systems designed to retain their state across periods of power loss, for cases both when the device has an excess of available energy and when power loss is unavoidable. Existing work with intermittent systems has focused on the problems inherent to the intermittent paradigm and ignored the security implications of persistent state across periods of power loss. The security of these devices is closely linked to their unique operational characteristics and are addressed here in two studies. First, the presence of an energy harvester creates an opportunity to use excess energy, available when additional energy is harvested after the local energy reservoir is filled, to precompute security related operations. Precomputation powered by this excess energy can reduce the cost of expensive tasks during periods of energy scarcity, potentially enabling the use of expensive security operations on traditionally unsecured devices. Second, when energy is limited and intermittent operation is required, the secure storage of checkpoints is a necessity to protect against adversary manipulation of the system state. To examine the secure storage of checkpoints a protocol is implemented to ensure the integrity and authenticity of a device's checkpoints, and evaluated for its energy overhead and performance. The cost of properly ensuring the integrity and authenticity of these checkpoints is examined to identify the overhead necessary to execute intermittent operations in a secure manner. Taken together, these studies lay the groundwork for a comprehensive view of the current state of intermittent device security. / Master of Science / This thesis explores two unique aspects of the intermittent computing paradigm, the precomputation during periods of excess energy and the security of system checkpoints. Intermittent systems are a class of embedded device that lack a classic, consistent, energy source and instead rely on transient energy collected from their surroundings. This removes the need for connection to a power grid or battery management, but introduces challenges in operation since the device can lose power at any time. Additionally, excess energy is available to these systems when they have filled their local energy reservoir, a capacitor or small rechargeable battery, and additional energy can still be collected form the environment. In this case, it is possible to begin precomputing energy intensive operations to enable more operations at a later time on a limited energy budget. Since their power source is inconsistent, intermittent systems checkpoint their current state to allow execution to resume at the beginning of the next power cycle. The security ramifications of saving the current system state into a checkpoint have not been considered in the state of the art. This thesis implements a protocol to properly secure system checkpoints and evaluates its performance to identify the energy overhead required for a secure checkpointing scheme. The results demonstrate the need for the development of more efficient solutions within the domain. Together, the two approaches presented in this thesis provide case studies on the behavior of intermittent devices when provided with either an excess or a dearth of energy. The optimization and improvement of modern intermittent devices will need to address both of these extremes as the field is further improved.
84

DESIGN OF A SOFTWARE GPS RECEIVER AND ITS MATLAB IMPLEMENTATION

Zhao, Yun, Zhang, Qishan 10 1900 (has links)
International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / The embedded system related hardware technology has experienced rapid development, and it provided the software technology with a huge space for growth. Therefore using software approaches to perform GPS receiver functions in a powerful and generic hardware platform is becoming more feasible. In this paper, the software GPS receiver technology and the design basics of the software receiver are discussed. Further in the Matlab simulation environment, the implementation of a software receiver for replacing the processing functions of ASIC in traditional GPS receivers, i.e. RF front end and multi-channel correlator, is presented. Some simulation results and implementation details are included.
85

JAVA FOR REAL-TIME TELEMETRY SYSTEMS

K/Bidy, Gilles 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / Because of an ever-increasing need for performance and high predictability in modern real-time telemetry systems, the Java programming language is typically not considered a viable option for embedded software development. Nevertheless, the Java platform provides many features that can easily be applied to embedded telemetry systems that other development platforms cannot match. But obviously, there are pitfalls to be aware of. This paper will present an alternative solution to address today’s problems in real-time telemetry systems and will cover the following topics: • Java development platforms for the embedded world • Impact on software portability and reusability • Performance and optimization techniques • Direct access to hardware devices • Memory management and garbage collection • Network-centric component-oriented architecture • Real-time examples from past experience • Future developments
86

An embedded augmented reality system

Groufsky, Michael Edward January 2011 (has links)
This report describes an embedded system designed to support the development of embedded augmented reality applications. It includes an integrated camera and built-in graphics acceleration hardware. An example augmented reality application serves as a demonstration of how these features are accessed, as well as providing an indication of the performance of the device. The embedded augmented reality development platform consists of the Gumstix Overo computer-on-module paired with the custom-built Overocam camera board. This device offers an ARM Cortex-A8 CPU running at 600 MHZ and 256 MB of RAM, along with the ability to capture VGA video at 30 frames per second. The device runs an operating system based on version 2.6.33 of the Linux kernel. The main feature of the device is the OMAP3530 multimedia applications processor from Texas Instruments. In addition to the ARM CPU, it provides an on-board 2D/3D graphics accelerator and a digital signal processor. It also includes a built-in camera peripheral interface, reducing the complexity of the camera board design. A working example of an augmented reality application is included as a demonstration of the device's capabilities. The application was designed to represent a basic augmented reality task: tracking a single marker and rendering a simple virtual object. It runs at around 8 frames per second when a marker is visible and 13 frames per second otherwise. The result of the project is a self-contained computing platform for vision-based augmented reality. It may either be used as-is or customised with additional hardware peripherals, depending on the requirements of the developer.
87

Enabling Reactive Design of Robust Real-Time Embedded Systems

Eriksson, Johan January 2017 (has links)
No description available.
88

Implementation of the DEECo component framework for embedded systems / Implementation of the DEECo component framework for embedded systems

Matěna, Vladimír January 2014 (has links)
Recent development in the field of distributed and decentralized cyber-physical systems led to emerge of DEECo model. As many DEECo use cases are embedded applications it is interesting to evaluate DEECo on embedded hardware. Currently there is only reference DEECo implementation which is written in Java thus cannot be used for embedded applications. As part of this thesis C++ DEECo mapping and embedded CDEECo++ framework were designed using FreeRTOS operating system for task scheduling and synchronization. An example application designed for the STM32F4 board demonstrates usability of the framework. This thesis contains description of the DEECo mapping into the C++ language, source codes of the CDEECo++ framework, documentation and example application including basic measurement of its real- time properties. Powered by TCPDF (www.tcpdf.org)
89

Energy Harvesting in Wireless Sensor Networks

Persson, Erik January 2019 (has links)
Over the past few years, the interest of remote wireless sensor networks has increased with the growth of Internet of Things technology. The wireless sensor network applications vary from tracking animal movement to controlling small electrical devices. Wireless sensors deployed in remote areas where the grid is unavailable are normally powered by batteries, inducing a limited lifespan for the sensor. This thesis work presents a solution to implement solar energy harvesting to a wireless sensor network. By gathering energy from the environment and using it in conjunction with an energy storage, the lifetime of a sensor node can be extended while at the same time reducing maintenance costs. To make sensor nodes in a network energy efficient, an adaptive controller of the nodes energy consumption can be used. A network consisting of a client node and a server node was created. The client node was powered by a small solar cell in conjunction with a capacitor. A linear-quadratic tracking algorithm was implemented to adaptively change the transmission rate for a node based on its current and previous battery level and the energy harvesting model. The implementation was done using only integers. To evaluate the system for extended run-times, the battery level was simulated using MATLAB. The system was simulated for different weather conditions. The simulation results show that the system is viable for both cloudy and sunny weather conditions. The integer linear-quadratic algorithm responds to change very abruptly in comparison to a floating point-version.
90

Using Smart Scheduling to Reduce the Negative Impacts of Instrumentation-based Defenses on Embedded Systems

Le Baron, Thomas 18 April 2019 (has links)
Real-time embedded systems can be found in a large number of devices we use, including safety-critical systems. Useful for their small size and low power consumption, they are also harder to protect against state-of-the-art attacks than general purpose systems due to their lack of hardware features. Even current defenses may not be applicable since instrumentation added to defend real-time embedded systems may cause them to miss their deadlines, rending them inoperable. We show that the static properties obtained by the scheduling policies can be used as security guarantees for the tasks composing the program. By completely securing a subset of the tasks of the program only using the scheduler policy, we remove the need to add external instrumentation on these tasks, reducing the amount of extra instructions needed to entirely protect the system. With less instrumentation, the overhead added by the defenses is reduced and can therefore be applied to a larger number of systems.

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