An Assessment of PIER Electric Grid Research 2003-2014 White Paper

This white paper describes the circumstances in California around the turn of the 21st century that led the California Energy Commission (CEC) to direct additional Public Interest Energy Research funds to address critical electric grid issues, especially those arising from integrating high penetrations of variable renewable generation with the electric grid. It contains an assessment of the beneficial science and technology advances of the resultant portfolio of electric grid research projects administered under the direction of the CEC by a competitively selected contractor, the University of California’s California Institute for Energy and the Environment, from 2003-2014

A dependable anisotropic magnetoresistance sensor system for automotive applications

The increasing usage of electronic systems in automotive applications aims to enhance passenger safety as well as the performance of the cars. In modern vehicles, the mechanical and hydraulic systems traditionally used have been replaced by X-by-wire systems in which the functions are performed by electronic components. However, the components required should be reliable, have a high-performance, low-cost and capable of operating for a long time in a highly dependable manner despite the harsh operating conditions in automotive applications. Dependability represents the reliance that a user justifiably poses on the service offered by a system, being this especially important in safety-critical applications in which a failure can constitute a threat to people or the environment. An Anisotropic Magnetoresistance (AMR) sensor is a type of magnetic sensor often used for angle measurements in cars. This sensor is affected by performance degradation and catastrophic faults that in principle cause the sensor to stop working suddenly. Therefore, the sensor dependability should be improved in order to guarantee that it will satisfy the continuous increasing dependability as well as accuracy requirements demanded by automotive applications. This research proposes an AMR sensor system that includes a fault-tolerant approach to handle catastrophic faults and self-X properties to maintain the performance of the sensor during its lifetime. Additionally, an interface with the IEEE 1687 standard has been considered, so the sensor is able to communicate with other components of the system in which it is integrated

Hierarchical Agent-based Adaptation for Self-Aware Embedded Computing Systems

Siirretty Doriast

A dependable AMR sensor system for automotive applications

The increasing replacement of mechanical parts by x-by-wire systems in automotive applications allows improving driver safety. These systems demand highly dependable sensors that ensure their functionality despite the harsh operating conditions. This means that the sensors should be capable of working continuously despite catastrophic faults and keeping the performance over time. An anisotropic magnetoresistance (AMR) sensor is a magnetic sensor commonly used for angle measurements in cars. It is affected by catastrophic faults and performance degradation due to undesired parameters included at the sensor outputs. Until now, physical redundancy is often used to handle catastrophic faults. For the performance, compensation factors for the undesired parameter, such as offset voltage, are estimated at the start of the sensor life. Although the undesired parameters drift due to aging effects, the sensor performance remains within the allowed tolerant band. However, this tolerant band will decrease in the future because the dependability requirements are continuously increasing. Therefore, it is necessary to consider strategies to guarantee the sensor performance over time. This paper proposes a system to improve the sensor dependability using analytical redundancy for catastrophic faults but also with self-x properties to maintain the sensor performance over time. Results indicate a dependability improvement in terms of reliability, with a reduction of 50% in the rate of uncovered failures. The safety requirement ASIL level D is satisfied, and with regard to maintainability, the sensor performance is maintained over time

A wireless sensor and actuator network for improving the electrical power grid dependability

This paper presents an overview of a Wireless Sensor and Actuator Network (WSAN) used to monitor an electrical power grid distribution infrastructure. The WSAN employs appropriate sensors to monitor key grid components, integrating both safety and security services, which improve the grid distribution dependability. The supported applications include, among others, video surveillance of remote secondary substations, which imposes special requirements from the point of view of quality of service and reliability. The paper presents the hardware and software architecture of the system together with performance results

Thermal Management for Dependable On-Chip Systems

This thesis addresses the dependability issues in on-chip systems from a thermal perspective. This includes an explanation and analysis of models to show the relationship between dependability and tempature. Additionally, multiple novel methods for on-chip thermal management are introduced aiming to optimize thermal properties. Analysis of the methods is done through simulation and through infrared thermal camera measurements

Dependable Embedded Systems

This Open Access book introduces readers to many new techniques for enhancing and optimizing reliability in embedded systems, which have emerged particularly within the last five years. This book introduces the most prominent reliability concerns from today’s points of view and roughly recapitulates the progress in the community so far. Unlike other books that focus on a single abstraction level such circuit level or system level alone, the focus of this book is to deal with the different reliability challenges across different levels starting from the physical level all the way to the system level (cross-layer approaches). The book aims at demonstrating how new hardware/software co-design solution can be proposed to ef-fectively mitigate reliability degradation such as transistor aging, processor variation, temperature effects, soft errors, etc. Provides readers with latest insights into novel, cross-layer methods and models with respect to dependability of embedded systems; Describes cross-layer approaches that can leverage reliability through techniques that are pro-actively designed with respect to techniques at other layers; Explains run-time adaptation and concepts/means of self-organization, in order to achieve error resiliency in complex, future many core systems