Concurrent Scheme

Journal ArticleThis paper describes an evolution of the Scheme language to support parallelism with tight coupling of control and data. Mechanisms are presented to address the difficult and related problems of mutual exclusion and data sharing which arise in concurrent language systems. The mechanisms are tailored to preserve Scheme semantics as much as possible while allowing for efficient implementation. Prototype implementations of the resulting language are described which have been completed. A third implementation is underway for the Mayfly, a distributed memory, twisted-torus communication topology, parallel processor, under development at the Hewlett-Packard Research Laboratories. The language model is particularly well suited for the Mayfly processor, as will be shown

Kawa|compiling dynamic languages to the Java VM

Many are interested in Java for its portable bytecodes and extensive libraries, but prefer a different language, especially for scripting. People have implemented other languages using an interpreter (which is slow), or by translating into Java source (with poor responsiveness for eval). Kawa uses an interpreter only for “simple” expressions; all non-trivial expressions (such as function definitions) are compiled into Java bytecodes, which are emitted into an in-memory byte array. This can be saved for later, or quickly loaded using the Java ClassLoader. Kawa is intended to be a framework that supports multiple source languages. Currently, it only supports Scheme, which is a lexically-scoped language in the Lisp family. The Kawa dialect of Scheme implements almost all of the current Scheme standard (R5RS), with a number of extensions, and is written in a efficient objectoriented style. It includes the full “numeric tower”, with complex numbers, exact infinite-precision rational arithmetic, and units. A number of extensions provide access to Java primitives, and some Java methods provide convenient access to Scheme. Since all Java objects are Scheme values and vice versa, this makes for a very powerful hybrid Java/Scheme environment. An implementation of ECMAScript (the standardized “core ” of JavaScript) is under construction. Other languages, including Emacs Lisp, are also being considered

Implementing Distributed Systems Using Linear Naming

Linear graph reduction is a simple computational model in which the cost of naming things is explicitly represented. The key idea is the notion of "linearity". A name is linear if it is only used once, so with linear naming you cannot create more than one outstanding reference to an entity. As a result, linear naming is cheap to support and easy to reason about. Programs can be translated into the linear graph reduction model such that linear names in the program are implemented directly as linear names in the model. Nonlinear names are supported by constructing them out of linear names. The translation thus exposes those places where the program uses names in expensive, nonlinear ways. Two applications demonstrate the utility of using linear graph reduction: First, in the area of distributed computing, linear naming makes it easy to support cheap cross-network references and highly portable data structures, Linear naming also facilitates demand driven migration of tasks and data around the network without requiring explicit guidance from the programmer. Second, linear graph reduction reveals a new characterization of the phenomenon of state. Systems in which state appears are those which depend on certain -global- system properties. State is not a localizable phenomenon, which suggests that our usual object oriented metaphor for state is flawed

Pattern detection platform using disruptive technologies to improve people’s daily tasks

Tesis por compendio de publicaciones[ES] En los últimos años la miniaturización de los dispositivos electrónicos y el abaratamiento de los procesos de fabricación de los componentes ha permitido que las redes de sensores inalámbricas sean cada vez mas importantes y se empleen en multitud de casos. Adicionalmente, y debido en parte a la mejora en cuanto a las capacidades de almacenamiento y procesamiento de datos se refiere, ha permitido construir sistemas sensibles al contexto en áreas como la medicina, la monitorización o la robótica que permiten hacer un análisis detallado y adaptable de los procesos y servicios que se pueden proporcionar a los usuarios. Esta tesis doctoral ha sido conformada mediante un “Compendio de Artículos” donde se analiza la aplicación de paradigmas de inteligencia artificial en 3 casos de estudio claramente diferenciados. Se ha planteado un novedoso sistema de localización en interiores que hace uso de técnicas bayesianas y fingerprinting, con objeto de automatizar y facilitar los procesos de adquisición de datos de calibración. A mayores, se presenta un exoesqueleto que es conectado a una arquitectura sensible al contexto con objeto de que los pacientes de rehabilitación hagan ejercicios de forma interactiva y haciendo uso de técnicas de realidad aumentada. En el último artículo, se hace hincapié en el diseño de una plataforma que hace uso de las redes inalámbricas de sensores, con objeto de monitorizar el estado de los aseos mediante la incorporación de agentes embebidos en dispositivos limitados computacionalmente. Esta información descentralizada es analizada con objeto de detectar posibles anomalías y facilitar la toma de decisiones. Uno de los principales hitos que se pretende con el estudio, es mostrar a la comunidad científica los diferentes resultados que se han obtenido en la investigación, solventando problemas cotidianos que han sido resueltos mediante la modelización de los casos de estudio mediante la utilización de arquitecturas multi-agente y sistemas expertos. El filtrado de señales, la utilización de clasificadores, minería de datos y la utilización de otras técnicas de Inteligencia Artificial han sido empleadas para la consecución exitosa de este trabajo

Slivers, computational modularity via synchronized lazy aggregates

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.Includes bibliographical references (p. 435-442).by Farnklyn Albin Turbak.Ph.D

An Analysis of the Myths That Bolster Efforts to Rewrite RICO and the Various Proposals for Reform: Mother of God-Is This the End of RICO?

In 1970 Congress enacted the Organized Crime Control Act, Title IX of which is known as the Racketeer Influenced and Corrupt Organizations Act, or RICO. Congress enacted the 1970 Act to strengthen[]the legal tools in the evidence-gathering process, [to] establish[] new penal prohibitions, and [to] provid[e] enhanced sanctions and new remedies .,, RICO covers violence, the provision of illegal goods and services, corruption in labor or management relations, corruption in government, and commercial fraud. Congress found in 1970 that the sanctions and remedies available to combat these crimes under the law then in force were unnecessarily limited in scope and impact. Consequently, it provided a wide range of new criminal and civil sanctions to control these offenses, including imprisonment, forfeiture, injunctions,and treble damage relief for persons injured in their business or property by violations of the statute.\u27 At the time, the President, the President\u27s Commission on Crime and Administration of Justice, and the American Bar Association called for the private civil remedies of RICO. In response, the Senate passed the Bill seventy-three to one.The House passed an amended Bill three hundred forty-one to twenty-six. The Senate passed the amended House Bill without objection,and the President signed the legislation on October 14, 1970.

An Analysis of the Myths that Bolster Efforts to Rewrite RICO and the Various Proposals for Reform: Mother of God - Is this the End of RICO?

In 1970 Congress enacted the Organized Crime Control Act, Title IX of which is known as the Racketeer Influenced and Corrupt Organizations Act, or RICO. At first, the Department of Justice moved slowly to use RICO in criminal prosecutions. Today, RICO is the prosecutor\u27s tool of choice in organized crime, political corruption, white-collar crime, terrorism, and neo-Nazi and anti-Semitic hate group prosecutions. The Department of Justice also is implementing the civil provisions of the Act. The private bar did not begin to bring civil RICO suits until about 1975. When it did, a firestorm of controversy broke out, and today RICO is endangered from a variety of quarters. The arguments against RICO are fueled by a series of myths that are not supported by a careful analysis of the statute, its legislative history, or the facts. The myths, however, have a debilitating impact on the interpretation and application of the statute. Chiefly, these myths undermine RICO\u27s basic legitimacy. When the statute\u27s legitimacy is undermined, efforts are facilitated to get the judiciary or Congress to rewrite the statute. If these efforts succeed, victims of sophisticated forms of crime everywhere will be harmed. Accordingly, these myths need to be thoroughly examined before any RICO reform goes forward