Study of fault-tolerant software technology

Presented is an overview of the current state of the art of fault-tolerant software and an analysis of quantitative techniques and models developed to assess its impact. It examines research efforts as well as experience gained from commercial application of these techniques. The paper also addresses the computer architecture and design implications on hardware, operating systems and programming languages (including Ada) of using fault-tolerant software in real-time aerospace applications. It concludes that fault-tolerant software has progressed beyond the pure research state. The paper also finds that, although not perfectly matched, newer architectural and language capabilities provide many of the notations and functions needed to effectively and efficiently implement software fault-tolerance

An Introduction to Database Systems

This textbook introduces the basic concepts of database systems. These concepts are presented through numerous examples in modeling and design. The material in this book is geared to an introductory course in database systems offered at the junior or senior level of Computer Science. It could also be used in a first year graduate course in database systems, focusing on a selection of the advanced topics in the latter chapters

Attribute-Level Versioning: A Relational Mechanism for Version Storage and Retrieval

Data analysts today have at their disposal a seemingly endless supply of data and repositories hence, datasets from which to draw. New datasets become available daily thus making the choice of which dataset to use difficult. Furthermore, traditional data analysis has been conducted using structured data repositories such as relational database management systems (RDBMS). These systems, by their nature and design, prohibit duplication for indexed collections forcing analysts to choose one value for each of the available attributes for an item in the collection. Often analysts discover two or more datasets with information about the same entity. When combining this data and transforming it into a form that is usable in an RDBMS, analysts are forced to deconflict the collisions and choose a single value for each duplicated attribute containing differing values. This deconfliction is the source of a considerable amount of guesswork and speculation on the part of the analyst in the absence of professional intuition. One must consider what is lost by discarding those alternative values. Are there relationships between the conflicting datasets that have meaning? Is each dataset presenting a different and valid view of the entity or are the alternate values erroneous? If so, which values are erroneous? Is there a historical significance of the variances? The analysis of modern datasets requires the use of specialized algorithms and storage and retrieval mechanisms to identify, deconflict, and assimilate variances of attributes for each entity encountered. These variances, or versions of attribute values, contribute meaning to the evolution and analysis of the entity and its relationship to other entities. A new, distinct storage and retrieval mechanism will enable analysts to efficiently store, analyze, and retrieve the attribute versions without unnecessary complexity or additional alterations of the original or derived dataset schemas. This paper presents technologies and innovations that assist data analysts in discovering meaning within their data and preserving all of the original data for every entity in the RDBMS

(Fase 2) bajo minería de datos. Caso de estudio: MOTOS ELECTROMUEBLES- Departamento de Arauca

Motos Electromuebles es una empresa con 6 años de experiencia en el mercado Araucano, su actividad comercial consta de venta de repuestos para motos Honda y Hero, servicio de mantenimiento para motos; actualmente cuentan con cuatro sedes en el Departamento de Arauca: Arauca, Tame, Arauquita y Saravena. La empresa cuenta con un sistema transaccional web que almacena todos los registros de las diferentes dependencias. La siguiente propuesta presenta un diseño y desarrollo de un módulo CRM (Customer Relationship Management) adaptado a la empresa Motos Electromuebles de Arauca, aplicando un modelo de minería de datos. La minería de datos es un mecanismo para explorar grandes cantidades de datos y convertirlo en información, para este caso se utiliza para encaminar los datos que tiene la empresa de clientes, organizarla y lograr obtener la información que se solicita. Un CRM es una herramienta comercial y de marketing importante para cualquier empresa, se centra en la relación empresa - cliente. Es el pilar donde se centra la fidelización del cliente y se aplicará las acciones de mercadeo. En el estado del arte se consigna una definición precisa y clara de los dos conceptos ya que se requiere tener la definición clara para generar el análisis y el módulo con las estrategias de marketing. La base tecnológica para el desarrollo de la propuesta es el gestor de base de datos MYSQL y un lenguaje de programación PHP, se plantea la idea de desarrollo adecuado para esta empresa. Además se realiza una toma de requerimientos que se deberá utilizar para hacer la clasificación de los roles de acceso, manejo y clasificación de los clientes para que la empresa haga la toma de decisiones y ayudar a la gestión de ventas.Motos Electromuebles es una empresa con 6 años de experiencia en el mercado Araucano, su actividad comercial consta de venta de repuestos para motos Honda y Hero, servicio de mantenimiento para motos; actualmente cuentan con cuatro sedes en el Departamento de Arauca: Arauca, Tame, Arauquita y Saravena. La empresa cuenta con un sistema transaccional web que almacena todos los registros de las diferentes dependencias. La siguiente propuesta presenta un diseño y desarrollo de un módulo CRM (Customer Relationship Management) adaptado a la empresa Motos Electromuebles de Arauca, aplicando un modelo de minería de datos. La minería de datos es un mecanismo para explorar grandes cantidades de datos y convertirlo en información, para este caso se utiliza para encaminar los datos que tiene la empresa de clientes, organizarla y lograr obtener la información que se solicita. Un CRM es una herramienta comercial y de marketing importante para cualquier empresa, se centra en la relación empresa - cliente. Es el pilar donde se centra la fidelización del cliente y se aplicará las acciones de mercadeo. En el estado del arte se consigna una definición precisa y clara de los dos conceptos ya que se requiere tener la definición clara para generar el análisis y el módulo con las estrategias de marketing. La base tecnológica para el desarrollo de la propuesta es el gestor de base de datos MYSQL y un lenguaje de programación PHP, se plantea la idea de desarrollo adecuado para esta empresa. Además se realiza una toma de requerimientos que se deberá utilizar para hacer la clasificación de los roles de acceso, manejo y clasificación de los clientes para que la empresa haga la toma de decisiones y ayudar a la gestión de ventas

XSEDE: eXtreme Science and Engineering Discovery Environment Third Quarter 2012 Report

The Extreme Science and Engineering Discovery Environment (XSEDE) is the most advanced, powerful, and robust collection of integrated digital resources and services in the world. It is an integrated cyberinfrastructure ecosystem with singular interfaces for allocations, support, and other key services that researchers can use to interactively share computing resources, data, and expertise.This a report of project activities and highlights from the third quarter of 2012.National Science Foundation, OCI-105357

Resilience-Building Technologies: State of Knowledge -- ReSIST NoE Deliverable D12

This document is the first product of work package WP2, "Resilience-building and -scaling technologies", in the programme of jointly executed research (JER) of the ReSIST Network of Excellenc

The Design of a High-Integrity Disk Management Subsystem

This dissertation describes and experimentally evaluates the design of the Logical Disk, a disk management subsystem that guarantees the integrity of data stored on disk even after system failures, while still providing performance competitive to other storage systems. Current storage systems that use the hard disk as storage medium, such as file systems, often do not provide sufficient protection against loss of data after a system failure. The designers of such systems are afraid that the amount of effort necessary for data protection would also result in too much loss of performance. The Logical Disk uses many different techniques to guarantee data integrity, including the support to execute multiple commands as one atomic action and avoiding `in-place updates' at all times. The techniques used to provide competitive performance include the technique of combining many, small write commands into one large, sequential, and thus efficient, write to disk, and clustering the data on disk continuously and automatically.Tanenbaum, A.S. [Promotor]Jonge, W. de [Copromotor

Anales del XIII Congreso Argentino de Ciencias de la Computación (CACIC)

Contenido: Arquitecturas de computadoras Sistemas embebidos Arquitecturas orientadas a servicios (SOA) Redes de comunicaciones Redes heterogéneas Redes de Avanzada Redes inalámbricas Redes móviles Redes activas Administración y monitoreo de redes y servicios Calidad de Servicio (QoS, SLAs) Seguridad informática y autenticación, privacidad Infraestructura para firma digital y certificados digitales Análisis y detección de vulnerabilidades Sistemas operativos Sistemas P2P Middleware Infraestructura para grid Servicios de integración (Web Services o .Net)Red de Universidades con Carreras en Informática (RedUNCI