Reduction of power dissipation in microprocessor design is becoming a key design constraint. This is motivated not only by portable electronics, in which battery weight and size is critical, but by heat dissipation issues in larger desktop and parallel machines as well. By identifying the major modes of computation of these processors and by proposing figures of merit for each of these modes, a power analysis methodology is developed. It allows the energy efficiency of various architectures to be quantified, and provides techniques for either individually optimizing or trading off throughput and energy consumption. The methodology is then used to qualify three important design principles for energy efficient microprocessor design. 1: Introduction Throughput and area have been the main forces driving microprocessor design, but recently the explosive growth in portable electronics has forced a shift in these design optimizations toward more power conscious solutions. Even for desktop un...

: Processors used in portable systems must provide highly energy-efficient operation, due to the importance of battery weight and size, without compromising high performance when the user requires it. The user-dependent modes of operation of a processor in portable systems are described and separate metrics for energy efficiency for each of them are found to be required. A variety of well known low-power techniques are re-evaluated against these metrics and in some cases are not found to be appropriate leading to a set of energy-efficient design principles. Also, the importance of idle energy reduction and the joint optimization of hardware and software will be examined for achieving the ultimate in lowenergy, high-performance design. 1. Introduction The recent explosive growth in portable electronics requires energy conscious design, without sacrificing performance. Simply increasing the battery capacity is not sufficient because the battery has become a significant fraction of the t...

Despite their increasing sophistication, wireless sensor networks still do not exploit the most powerful of the human senses: vision. Indeed, vision provides humans with unmatched capabilities to distinguish objects and identify their importance. Our work seeks to provide sensor networks with similar capabilities by exploiting emerging, cheap, lowpower and small form factor CMOS imaging technology. In fact, we can go beyond the stereo capabilities of human vision, and exploit the large scale of sensor networks to provide multiple, widely different perspectives of the physical phenomena. To this end, we have developed a small camera device called Cyclops that bridges the gap between the computationally constrained wireless sensor nodes such as Motes, and CMOS imagers which, while low power and inexpensive, are nevertheless designed to mate with resource-rich hosts. Cyclops enables development of new class of vision applications that span across wireless sensor network. We describe our hardware and software architecture, its temporal and power characteristics and present some representative applications.

The era of low power microelectronics began with the invention of the transistor in the late 1940 's and came of age with the invention of the integrated circuit in the late 1950's. Historically, the most demanding applications of low power microelectronics have been battery operated products such as wrist watches, hearing aids, implantable cardiac pacemakers, pocket calculators, pagers, cellular telephones and prospectively the hand-held multi-media terminal. However, in the early 1990's low power microelectronics rapidly evolved from a substantial tributary to the mainstream of microelectronics. The principal reasons for this transformation were the increasing packing density of transistors and increasing clock frequencies of CMOS microchips pushing heat removal and power distribution to the forefront of the problems confronting the advance of microelectronics. The distinctive thesis of this discussion is that future opportunities

In this dissertation, we examine the problem of performing handoff quickly in cellular data networks. We define handoff as the process of reconfiguring the mobile host, wireless network and backbone wired network to support communication after a user enters a different cell of the wireless network. In order to support applications and protocols used on wired networks, the handoff processing must not significantly affect the typical end-to-end loss or delay of any communications. This dissertation concentrates on two specific areas of handoff processing: routing updates and state distribution. The techniques we use to solve these problems are: 1. Multicast to set up routing in advance of handoff. 2. Hints

This paper describes a software architecture for the Infopad mobile computing system. The software architecture, called Infonet, supports the use of multimedia services in the Infopad mobile system. First, an overview of the Infopad project is presented and the project's basic characteristics are outlined. Next, the Infonet architecture is defined and its use is illustrated by three scenarios: pad activation, application initialization, and handoff. Measurements from an existing prototype demonstrate the system`s feasibility. Finally, the future direction of work on the Infonet system is discussed. 1 Introduction Infopad is an on-going project in the Electrical Engineering & Computer Sciences Department at the University of California at Berkeley. The goal of this project is to create a mobile computing environment which supports multimedia. An overview of Infopad system is shown in Figure 1 and is described in [Sheng92]. The basis of the Infopad system design is the Pad, a portable t...

Some of the most important recent trends in computer systems are the emerging use of multimedia Internet services, the popularity of portable computing, and the development of wireless data communications. The primary goal of the InfoPad project is to combine these trends to create a system that provides ubiquitous information access. The system is built around a low-power, lightweight wireless multimedia terminal [1] that operates in indoor environments and supports a high density of users. The InfoPad system uses a number of innovative techniques to provide the high-bandwidth connectivity, portability, and user interface needed for this environment. This article describes the design, implementation, and evaluation of the software network and application services that support the InfoPad terminal. We believe that future users will demand network connectivity

Declaration 10 Copyright 11 The author 12 Acknowledgements 13 1

Reduction of power dissipation in microprocessor design is becoming a key design constraint. This is moti-vated not only by portable electronics, in which battery weight and size is critical, but by heat dissipation issues in larger desktop and parallel machines as well. By identify-ing the major modes of computation of these processors and by proposing figures of merit for each of these modes, a power analysis methodology is developed. It allows the energy efficiency of various architectures to be quantified, and provides techniques for either individually optimizing or trading off throughput and energy consumption. The methodology is then used to qualify three important design principles for energy efficient microprocessor design. 1

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