Asymptotically Zero Energy Computing Using Split-Level Charge Recovery Logic

The dynamic power requirement of CMOS circuits is rapidly becoming a major concern in the design of personal information systems and large computers. In this work we present a number of new CMOS logic families, Charge Recovery Logic (CRL) as well as the much improved Split-Level Charge Recovery Logic (SCRL), within which the transfer of charge between the nodes occurs quasistatically. Operating quasistatically, these logic families have an energy dissipation that drops linearly with operating frequency, i.e., their power consumption drops quadratically with operating frequency as opposed to the linear drop of conventional CMOS. The circuit techniques in these new families rely on constructing an explicitly reversible pipelined logic gate, where the information necessary to recover the energy used to compute a value is provided by computing its logical inverse. Information necessary to uncompute the inverse is available from the subsequent inverse logic stage. We demonstrate the low energy operation of SCRL by presenting the results from the testing of the first fully quasistatic 8 x 8 multiplier chip (SCRL-1) employing SCRL circuit techniques.

Reconfigurable Architectures for General-Purpose Computing

General-purpose computing devices allow us to (1) customize computation after fabrication and (2) conserve area by reusing expensive active circuitry for different functions in time. We define RP-space, a restricted domain of the general-purpose architectural space focussed on reconfigurable computing architectures. Two dominant features differentiate reconfigurable from special-purpose architectures and account for most of the area overhead associated with RP devices: (1) instructions which tell the device how to behave, and (2) flexible interconnect which supports task dependent dataflow between operations. We can characterize RP-space by the allocation and structure of these resources and compare the efficiencies of architectural points across broad application characteristics. Conventional FPGAs fall at one extreme end of this space and their efficiency ranges over two orders of magnitude across the space of application characteristics. Understanding RP-space and its consequences allows us to pick the best architecture for a task and to search for more robust design points in the space. Our DPGA, a fine- grained computing device which adds small, on-chip instruction memories to FPGAs is one such design point. For typical logic applications and finite- state machines, a DPGA can implement tasks in one-third the area of a traditional FPGA. TSFPGA, a variant of the DPGA which focuses on heavily time-switched interconnect, achieves circuit densities close to the DPGA, while reducing typical physical mapping times from hours to seconds. Rigid, fabrication-time organization of instruction resources significantly narrows the range of efficiency for conventional architectures. To avoid this performance brittleness, we developed MATRIX, the first architecture to defer the binding of instruction resources until run-time, allowing the application to organize resources according to its needs. Our focus MATRIX design point is based on an array of 8-bit ALU and register-file building blocks interconnected via a byte-wide network. With today's silicon, a single chip MATRIX array can deliver over 10 Gop/s (8-bit ops). On sample image processing tasks, we show that MATRIX yields 10-20x the computational density of conventional processors. Understanding the cost structure of RP-space helps us identify these intermediate architectural points and may provide useful insight more broadly in guiding our continual search for robust and efficient general-purpose computing structures.

New Architectural Models for Visibly Controllable Computing: The Relevance of Dynamic Object Oriented Architectures and Plan Based Computing Models

Traditionally, we've focussed on the question of how to make a system easy to code the first time, or perhaps on how to ease the system's continued evolution. But if we look at life cycle costs, then we must conclude that the important question is how to make a system easy to operate. To do this we need to make it easy for the operators to see what's going on and to then manipulate the system so that it does what it is supposed to. This is a radically different criterion for success. What makes a computer system visible and controllable? This is a difficult question, but it's clear that today's modern operating systems with nearly 50 million source lines of code are neither. Strikingly, the MIT Lisp Machine and its commercial successors provided almost the same functionality as today's mainstream sytsems, but with only 1 Million lines of code. This paper is a retrospective examination of the features of the Lisp Machine hardware and software system. Our key claim is that by building the Object Abstraction into the lowest tiers of the system, great synergy and clarity were obtained. It is our hope that this is a lesson that can impact tomorrow's designs. We also speculate on how the spirit of the Lisp Machine could be extended to include a comprehensive access control model and how new layers of abstraction could further enrich this model.

A Privacy Conscious Bluetooth Infrastructure for Location Aware Computing

We present a low cost and easily deployed infrastructure for location aware computing that is built using standard Bluetooth® technologies and personal computers. Mobile devices are able to determine their location to room-level granularity with existing bluetooth technology, and to even greater resolution with the use of the recently adopted bluetooth 1.2 specification, all while maintaining complete anonymity. Various techniques for improving the speed and resolution of the system are described, along with their tradeoffs in privacy. The system is trivial to implement on a large scale – our network covering 5,000 square meters was deployed by a single student over the course of a few days at a cost of less than US$1,000.

Failure-Oblivious Computing and Boundless Memory Blocks

Memory errors are a common cause of incorrect software execution and security vulnerabilities. We have developed two new techniques that help software continue to execute successfully through memory errors: failure-oblivious computing and boundless memory blocks. The foundation of both techniques is a compiler that generates code that checks accesses via pointers to detect out of bounds accesses. Instead of terminating or throwing an exception, the generated code takes another action that keeps the program executing without memory corruption. Failure-oblivious code simply discards invalid writes and manufactures values to return for invalid reads, enabling the program to continue its normal execution path. Code that implements boundless memory blocks stores invalid writes away in a hash table to return as the values for corresponding out of bounds reads. he net effect is to (conceptually) give each allocated memory block unbounded size and to eliminate out of bounds accesses as a programming error. We have implemented both techniques and acquired several widely used open source servers (Apache, Sendmail, Pine, Mutt, and Midnight Commander).With standard compilers, all of these servers are vulnerable to buffer overflow attacks as documented at security tracking web sites. Both failure-oblivious computing and boundless memory blocks eliminate these security vulnerabilities (as well as other memory errors). Our results show that our compiler enables the servers to execute successfully through buffer overflow attacks to continue to correctly service user requests without security vulnerabilities.

Diseño Flash de recursos web y multimedia para la enseñanza : materiales para la formación a distancia del profesorado.

Resumen basado en la publicación

Aula Multimedia

El enlace es con los ??ltimos bloques: el proyecto Tandem y los recursos en lenguas extranjeras

Comunicación, Imagen y Publicidad : recursos multimedia para la educación audiovisual.

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Comunicación, Imagen y Publicidad : recursos multimedia para la educación audiovisual.

Resumen basado en la publicación

Comunicación, Imagen y Publicidad : recursos multimedia para la educación audiovisual.

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Gu??a multimedia de recursos educativos para alumnado con necesidades educativas especiales

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La CDU en la Ense??anza Secundaria : actividades multimedia

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Colours : contenido multimedia de inglés para Educación infantil.

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Llibros interactivos multimedia en llingua asturiana. 'Libros interactivos multimedia en lengua asturiana'

Este CD-ROM presenta una serie de actividades interactivas muy variadas realizadas con el programa EDILIM sobre temas referentes a cultura asturiana. Fue dise??ado por un grupo de trabajo integrado por profesores de Educaci??n Primaria, Secundaria y Bachillerato. Cada participante elabor?? distintas opciones para coordinar interdisciplinariamente la materia abord??ndose los siguientes temas: cosas de Asturias (mitolog??a, arte, deportes, costumbres, refranes...), los animales, los ??rboles, el campo y la casa, la comida, las diversiones y el colegio. Tiene como objetivo que el alumnado de Llingua Asturiana y Lliteratura pueda ser llevado al aula de inform??tica y manejar all?? los contenidos interactivos.

Diseño, evaluación y aplicación de un recurso multimedia en la enseñanza del mini balonmano en maestros especialistas en Educación Física.

Servir como punto de partida a nuevas experiencias en campos similares tanto a nivel deportivo como a nivel universitario, con dos objetivos generales claros. Por una parte, diseñar y aplicar un material multimedia (DVD) para la enseñanza del mini balonmano en maestros especialistas en Educación Física. Por otra, valorar la utilización de un material multimedia interactivo en la Asignatura de Iniciación Deportiva. Se utiliza una metodología integradora, es decir, técnicas cuantitativas y cualitativas. Esta metodología se apoya en la elaboración de un cuestionario para conocer la opinión de una serie de expertos sobre la validez del instrumento, en este caso un DVD interactivo. En la estructura del DVD se utilizó, fundamentalmente, el programa Macromedia Director MX 2004, una parte importante del DVD consiste en vídeos y animaciones. Este trabajo de investigación consta de dos partes: la elaboración y validación de un material interactivo para la enseñanza del mini balonmano. En la primera parte los sujetos clave lo forman un equipo multidisciplinar de expertos, en concreto, los evaluadores que fueron cinco licenciados en Educación Física. El trabajo de investigación final se desarrolla durante los cursos 2004-05 y 2005-06 y consistió, fundamentalmente, en la aplicación del DVD interactivo para el aprendizaje del mini balonmano con alumnos universitarios de la asignatura 'Iniciación Deportiva II', con un total de 55 alumnos, 45 en el curso 2004-05 y 10 en el curso 2005-06. Las herramientas utilizadas se agrupan en dos grandes bloques: 1- Herramientas para la elaboración del DVD (varios programas informáticos) 2-Herramientas para la validación del DVD (diarios y grupos de discusión). Las principales conclusiones han sido las siguientes: los alumnos muestran su satisfacción, en cuanto a la metodología utilizada, los contenidos presentados y con el aprendizaje realizado. En cuanto al método utilizado muestran su satisfacción no solo por lo novedoso sino por la aplicación en su futuro devenir profesional como especialistas en Educación Física. Respecto a los contenidos, valoran, la simplicidad de su exposición así como la adecuación e idoneidad de los mismos, destacando su progresión continua. Los incrementos en el aprendizaje han sido muy superiores cuando los alumnos utilizan el DVD interactivo, con lo cual se reafirma que la utilización de un interactivo mejora el aprendizaje, máxime si se utiliza no sólo como un único medio de aprendizaje, sino como un complemento a la enseñanza presencial. Finalmente, se plantea que otros investigadores continúen en esta linea, en asignaturas diferentes, y que se debe completar la investigación sobre la influencia de los materiales multimedia en la formación. Se cree firmemente que al estar inmersos en la era de las nuevas tecnologías, no aplicarlas en el campo de la formación deportiva, sería dejar a los docentes o a los futuros entrenadores de una serie de herramientas que van a facilitar, sin duda, su preparación y que, por tanto, en definitiva, mejora la preparación de los alumnos y deportistas a su cargo.