Real-time and fault tolerance in distributed control software

Closed loop control systems typically contain multitude of spatially distributed sensors and actuators operated simultaneously. So those systems are parallel and distributed in their essence. But mapping this parallelism onto the given distributed hardware architecture, brings in some additional requirements: safe multithreading, optimal process allocation, real-time scheduling of bus and network resources. Nowadays, fault tolerance methods and fast even online reconfiguration are becoming increasingly important. All those often conflicting requirements, make design and implementation of real-time distributed control systems an extremely difficult task, that requires substantial knowledge in several areas of control and computer science. Although many design methods have been proposed so far, none of them had succeeded to cover all important aspects of the problem at hand. [1] Continuous increase of production in embedded market, makes a simple and natural design methodology for real-time systems needed more then ever

The Role of Consumers in the Adoption of Alternatively Fueled Vehicles and Mitigation of Vulnerabilities Associated with Electric Vehicle Charging

Electric vehicles have the potential to replace traditional automobiles as the primary form of transportation. Despite major improvements in technology and an expanding focus on climate change making electric vehicles more practical than ever before, consumers are still wary of adopting them for legitimate reasons such as costs and charging infrastructure. Therefore, a concerted effort must be made to persuade individuals and companies to adopt this beneficial technology to reduce the carbon footprint and catalyze the construction of important charging infrastructure. Though there are a multitude of benefits to adopting electric vehicles, there will be some negative effects on the power grid as a result of consumers adopting this new technology. To maintain and improve grid reliability, it is crucial to explore solutions to mitigate the potential effects of electric vehicles on the grid before widespread adoption occurs. Many suggested programs require customers to behave in a certain way, such as shifting their demand to off-peak times, or purchase batteries or chargers with specific capabilities. However, convincing consumers to participate in these programs is incredibly difficult, and programs such as time-of-use scheduling may only provide marginal improvements in grid conditions, like time-of-use programs. In this thesis, the benefits of electric vehicle adoption in terms of carbon reduction are observed to determine the benefit to individuals and fleet managers looking to reduce carbon emissions. Then, the effects of electric vehicles on a residential grid are explored and the impacts of time-of-use programs are analyzed. Finally, the role of the consumer in the transformation of the energy and transportation sectors is discussed with an emphasis on potential programs and incentives to persuade consumers to adopt electric vehicles and then aid in mitigating the effects of their charging systems

A Configurable Transport Layer for CAF

The message-driven nature of actors lays a foundation for developing scalable and distributed software. While the actor itself has been thoroughly modeled, the message passing layer lacks a common definition. Properties and guarantees of message exchange often shift with implementations and contexts. This adds complexity to the development process, limits portability, and removes transparency from distributed actor systems. In this work, we examine actor communication, focusing on the implementation and runtime costs of reliable and ordered delivery. Both guarantees are often based on TCP for remote messaging, which mixes network transport with the semantics of messaging. However, the choice of transport may follow different constraints and is often governed by deployment. As a first step towards re-architecting actor-to-actor communication, we decouple the messaging guarantees from the transport protocol. We validate our approach by redesigning the network stack of the C++ Actor Framework (CAF) so that it allows to combine an arbitrary transport protocol with additional functions for remote messaging. An evaluation quantifies the cost of composability and the impact of individual layers on the entire stack

The effect of overloading on reliability of wheel loader structural components

This research attempts to provide a fundamental understanding into the relationship between the productivity of material handling equipment, specifically wheel loaders, and their ability to operate reliably when subjected to high overload conditions. The overall aim is to determine the effect of overloading the bucket on wheel loader reliability. The specific objectives of the research are to: 1) evaluate the effect of overloading the bucket on wheel loader productivity; 2) examine the effect of overloading the bucket on hydraulic pressures in the hoist cylinders (used as a proxy for forces on a wheel loader); and 3) investigate the effect of overloading the bucket on the reliability of structural components of a wheel loader. To achieve these objectives, the research used data from on-board equipment monitors from the global fleet of ultra-class wheel loaders for a specific original equipment manufacturer to test the various research hypotheses. The data included production data, failure and repair data, and hydraulic cylinder pressures, which were used as a proxy for stresses on structural components. ANOVA and Pearson and Spearman correlations tests were performed on data samples to test the hypotheses. Duty-cycle relationships were established using linear life stress relationships ratios for the wheel loaders structural components. The research showed that, while higher bucket loads increase productivity, there is evidence that they slow down the loading cycle, may be detrimental to productivity. The hoist cylinder pressure increased with increasing payload weight. The reliability of the structural components was similar in both the standard and duty-cycle cases; although, the accuracy of the reliability models increased when the models accounted for duty-cycles --Abstract, page iii

Intelligent Microgrids

Center for Electromechanic

Exploring the relationship between role overload and intention to leave the profession among elementary school teachers

Teacher role overload has vibrantly been of a considerable concern for school administrators since the birth of formal education. The phenomenon often leads to teacher early departure from the profession due to uncontrolled stressors. This study investigates the relationship between role overload and intention to leave the profession among teachers in three Chinese medium elementary schools in Malaysia. It also explores whether or not role overload exists in the sampled schools. The study uses a convenience sampling technique and distributed 65 survey questionnaires to the sampled school teachers. The findings reveal that role overload had moderately correlated with intention to leave the profession among teachers in the sampled schools. Furthermore, the findings also disclose that aspects role overload moderately existed in the settings of the sampled schools. The practical and theoretical implications of the study for teachers, school administrators, and further research on the teachers? role overload related issues were also addressed