Temperature Regulation in Multicore Processors Using Adjustable-Gain Integral Controllers

This paper considers the problem of temperature regulation in multicore processors by dynamic voltage-frequency scaling. We propose a feedback law that is based on an integral controller with adjustable gain, designed for fast tracking convergence in the face of model uncertainties, time-varying plants, and tight computing-timing constraints. Moreover, unlike prior works we consider a nonlinear, time-varying plant model that trades off precision for simple and efficient on-line computations. Cycle-level, full system simulator implementation and evaluation illustrates fast and accurate tracking of given temperature reference values, and compares favorably with fixed-gain controllers.Comment: 8 pages, 6 figures, IEEE Conference on Control Applications 2015, Accepted Versio

Electrostrictive Polymers for Mechanical-to-Electrical Energy Harvesting

Research of electrostrictive polymers has generated new opportunities for harvesting energy from the surrounding environment and converting it into usable electrical energy. Piezoelectric ceramic based devices have long been used in energy harvesting for converting mechanical motion to electrical energy. Nevertheless, those materials tend to be unsuitable for low-frequency mechanical excitations such as human movement. Since organic polymers are typically softer and more flexible, the translated electrical energy output is considerably higher under the same mechanical force. Currently, investigations in using electroactive polymers for energy harvesting, and mechanical-to-electrical energy conversion, are beginning to show potential for this application. In this paper we discuss methods of energy harvesting using membrane structures and various methods used to convert it into usable energy. Since polymers are typically used in capacitive energy harvesting designs, the uses of polymer materials with large relative permittivities have demonstrated success for mechanical to electrical energy conversion. Further investigations will be used to identify suitable micro-electro mechanical systems (MEMs) structures given specific types of low-frequency mechanical excitations (10-100Hz)

PVDF-TrFE Electroactive Polymer Mechanical-to-Electrical Energy Harvesting Experimental Bimorph Structure

Research of electrostrictive polymers has generated new opportunities for harvesting energy from the surrounding environment and converting it into usable electrical energy. Electroactive polymer (EAP) research is one of the new opportunities for harvesting energy from the natural environment and converting it into usable electrical energy. Piezoelectric ceramic based energy harvesting devices tend to be unsuitable for low-frequency mechanical excitations such as human movement. Organic polymers are typically softer and more flexible therefore translated electrical energy output is considerably higher under the same mechanical force. In addition, cantilever geometry is one of the most used structures in piezoelectric energy harvesters, especially for mechanical energy harvesting from vibrations. In order to further lower the resonance frequency of the cantilever microstructure, a proof mass can be attached to the free end of the cantilever. Mechanical analysis of an experimental bimorph structure was provided and led to key design rules for post-processing steps to control the performance of the energy harvester. In this work, methods of materials processing and the mechanical to electrical conversion of vibrational energy into usable energy were investigated. Materials such as polyvinyledenedifluoridetetra-fluoroethylene P(VDF-TrFE) copolymer films (1um thick or less) were evaluated and presented a large relative permittivity and greater piezoelectric β-phase without stretching. Further investigations will be used to identify suitable micro-electromechanical systems (MEMs) structures given specific types of low-frequency mechanical excitations (10-100Hz)

A Compact CMOS Memristor Emulator Circuit and its Applications

Conceptual memristors have recently gathered wider interest due to their diverse application in non-von Neumann computing, machine learning, neuromorphic computing, and chaotic circuits. We introduce a compact CMOS circuit that emulates idealized memristor characteristics and can bridge the gap between concepts to chip-scale realization by transcending device challenges. The CMOS memristor circuit embodies a two-terminal variable resistor whose resistance is controlled by the voltage applied across its terminals. The memristor 'state' is held in a capacitor that controls the resistor value. This work presents the design and simulation of the memristor emulation circuit, and applies it to a memcomputing application of maze solving using analog parallelism. Furthermore, the memristor emulator circuit can be designed and fabricated using standard commercial CMOS technologies and opens doors to interesting applications in neuromorphic and machine learning circuits.Comment: Submitted to International Symposium of Circuits and Systems (ISCAS) 201

A technology based complexity model for reversible Cuccaro ripple-carry adder

Reversible logic provides an alternative to classical computing, that may overcome many of the power dissipation problems. The paper presents a simple complexity model, from the study of a cascade of Cuccaro adders processed in standard 0.35 micrometer CMOS technology