Abstract

International audience; Burn-In (BI) test is usually applied in manufacturing process to screen out chip early life failures, especially for safety critical applications. Unfortunately, this test method has elevated costs for companies. In recent days, Faster-than-at-Speed-Test (FAST) has become a useful technique to discover small delay defects. At the same time, overclocking methods to enhance system performances have been studied, which focus on temperature management to preserve system functionalities. In this paper, a FAST technique is approached with the aim of intentionally provoking a thermal overheating in the microprocessor by mean of the execution of functional test programs, partly regardless of system behavior preservation. The goal is to introduce an internal stress stronger than current procedures used during BI in order to speed up early detection of latent faults. The method illustrates how to avoid blocking configurations due to timing constraints violation and leads to a significant increase of the switching activity. Experimental results on a MIPS architecture show that, by using the described technique, the processor is not falling into an unpredictable state even at frequencies up to about 20 times higher than the nominal one and the switching activity is increasing up to 300% per nanoseconds.

Abstract

Today's combustion engines have low efficiency and a large amount of useful energy converts to heat as waste in different type of vehicles. Improving the dynamics of the car body, injection system, the shape of the internal engine components and manipulating the fuel compositions have had influence on fuel economy, but still less than 50% of energy in the fuel is converted to useful mechanical power. Since the lost energy escapes through the exhaust system as heat, taking advantage of thermoelectricity, part of that energy can be converted to useful electrical energy, improving the overall efficiency. However, the output voltage from a thermoelectric generator is a function of hot and cold side temperature and since, the electrical system of the vehicle operates with constant voltage, the use of a power converter is necessary. In this paper, simulation and experimental results of such a high-efficiency converter(94-96%), designed for thermoelectric generators on heavy duty vehicles is presented and discussed. "p"QC 20150904

Abstract

hieving energy efficiency has recently become an essential aim of networking research due to the ever increasing power consumption and CO2 emissions generated by large data networks. For this problem, the emerging paradigm of Software-Defined Networks (SDN) can be seen as an attractive solution. In these networks an energy-aware routing model could be easily implemented leveraging the control and data plane separation. This paper addresses the problem of optimizing the power consumption in SDN using an energy-aware traffic engineering approach that minimizes the number of links that can be used to satisfy a given traffic demand. Different from previous works, we focus on optimizing energy consumption in OpenFlow networks with in-band control traffic. Our approach also considers performance constraints that are crucial in the correct operation of SDN, such as bounded delay for the control plane traffic and load balance between controllers. First, we present a complete formulation of the optimization problem involving the routing requirements for control and data plane communications. To reduce the time complexity of our model in large-scale topologies we derive a heuristic algorithm. Significant values of energy saving (up to 60%) are reached in the simulations using real topologies and demands data. Peer Reviewed

Abstract

For lack of the appropriate global distribution of dc currents, the conventional suppression method to suppress dc bias based on capacitive dc blocking device (BD) redirects current to the ground as much as possible, which predisposes to the exceeding neutral current of other transformers in the regional power grid and leads to the contradiction between the power grid corporation and other public enterprises. Therefore, this paper presents a flexible suppression method for dc bias based on a novel dc-bias suppression device. First, a current balancing device (CBD) based on adjustable parallel resistances is designed. The mathematical model for global optimal switching of CBDs is established by a field-circuit coupling method with the equivalent resistance network of an ac system along with the location of substations and ground electrodes. The optimal switching scheme to minimize the global maximum dc current is obtained by gravitational search algorithm. Based on the aforementioned work, we propose a suppression strategy considering electro-corrosion of metal pipelines. The effectiveness and superiority of suppression methods are verified by comparative case studies of the Yichang power grid.