SOPA - a self organizing processing and streaming architecture

This paper describes SOPA, a component framework that is an essential part of the lecture recording system E-Chalk. It envisiones a general processing and streaming architecture featuring autonomous assembly of stream processing components. The goal is to provide an easy to use framework where dynamically organized processing graphs are build out of components from various distributed sources. Based on state-of-the-art solutions for component based software development the system simplifies the implementation and the configuration of multimedia streaming applications and associated tools. It supports stream synchronization transparently while extending components are installed on the fly according to the existing requirements that may change at any time

Ontological Con guration Management for Wireless Mesh Routers

This is a post-peer-review, pre-copyedit version of an article published in Lecture Notes in Computer Science. The final authenticated version is available online at: https://doi.org/10.1007/978-3-642-04968-2_10[Abstract] Wireless mesh networks (WMNs) are a category of wireless networks that are self-organized, robust and which offer more flexible client coverage with less equipment requirements than wired networks. In WMNs, mesh routers constitute the network’s “backbone”. The distributed, ever-changing and ad-hoc nature of these networks poses new challenges in configuration management. In order to face them, we modelize the configuration and semantics of a preexisting mesh router using the CIM model and OWL ontology language and implementing XSLT transformations from the original configuration format to CIM/OWL and back. We thus represent it in a higher level of abstraction, an ontological representation that supports configuration semantic checking, policy enforcing and reasoning on the configuration of WMN nodes. We also use the capabilities of our AdCIM framework for persistence and the generation of web configuration interfaces.Ministerio de Educación y Ciencia; TIN2007-67537-C03Xunta de Galicia; PGIDIT06PXIB105228PRMinistère de l'Enseignement supérieur, de la Recherche et de l'Innovation; ANR-05-RNRT-012-0

Efficient service discovery in wide area networks

Living in an increasingly networked world, with an abundant number of services available to consumers, the consumer electronics market is enjoying a boom. The average consumer in the developed world may own several networked devices such as games consoles, mobile phones, PDAs, laptops and desktops, wireless picture frames and printers to name but a few. With this growing number of networked devices comes a growing demand for services, defined here as functions requested by a client and provided by a networked node. For example, a client may wish to download and share music or pictures, find and use printer services, or lookup information (e.g. train times, cinema bookings). It is notable that a significant proportion of networked devices are now mobile. Mobile devices introduce a new dynamic to the service discovery problem, such as lower battery and processing power and more expensive bandwidth. Device owners expect to access services not only in their immediate proximity, but further afield (e.g. in their homes and offices). Solving these problems is the focus of this research. This Thesis offers two alternative approaches to service discovery in Wide Area Networks (WANs). Firstly, a unique combination of the Session Initiation Protocol (SIP) and the OSGi middleware technology is presented to provide both mobility and service discovery capability in WANs. Through experimentation, this technique is shown to be successful where the number of operating domains is small, but it does not scale well. To address the issue of scalability, this Thesis proposes the use of Peer-to-Peer (P2P) service overlays as a medium for service discovery in WANs. To confirm that P2P overlays can in fact support service discovery, a technique to utilise the Distributed Hash Table (DHT) functionality of distributed systems is used to store and retrieve service advertisements. Through simulation, this is shown to be both a scalable and a flexible service discovery technique. However, the problems associated with P2P networks with respect to efficiency are well documented. In a novel approach to reduce messaging costs in P2P networks, multi-destination multicast is used. Two well known P2P overlays are extended using the Explicit Multi-Unicast (XCAST) protocol. The resulting analysis of this extension provides a strong argument for multiple P2P maintenance algorithms co-existing in a single P2P overlay to provide adaptable performance. A novel multi-tier P2P overlay system is presented, which is tailored for service rich mobile devices and which provides an efficient platform for service discovery

Services and Policies for Care at Home

It is argued that various factors including the increasingly ageing population will require more care services to be delivered to users in their own homes. Desirable characteristics of such services are outlined. The Open Services Gateway initiative has been adopted as a widely accepted framework that is particularly suitable for developing home care services. Service discovery in this context is enhanced through ontologies that achieve greater flexibility and precision in service description. A service ontology stack allows common concepts to be extended for new services. The architecture of a policy system for home care is explained. This is used for flexible creation and control of new services. The core policy language and its extension for home care are introduced, and illustrated through typical examples. Future extensions of the approach are discussed

A Statically Typed Logic Context Query Language With Parametric Polymorphism and Subtyping

The objective of this thesis is programming language support for context-sensitive program adaptations. Driven by the requirements for context-aware adaptation languages, a statically typed Object-oriented logic Context Query Language  (OCQL) was developed, which is suitable for integration with adaptation languages based on the Java type system. The ambient information considered in context-aware applications often originates from several, potentially distributed sources. OCQL employs the Semantic Web-language RDF Schema to structure and combine distributed context information. OCQL offers parametric polymorphism, subtyping, and a fixed set of meta-predicates. Its type system is based on mode analysis and a subset of Java Generics. For this reason a mode-inference approach for normal logic programs that considers variable aliasing and sharing was extended to cover all-solution predicates. OCQL is complemented by a service-oriented context-management infrastructure that supports the integration of OCQL with runtime adaptation approaches. The applicability of the language and its infrastructure were demonstrated with the context-aware aspect language CSLogicAJ. CSLogicAJ aspects encapsulate context-aware behavior and define in which contextual situation and program execution state the behavior is woven into the running program. The thesis concludes with a case study analyzing how runtime adaptation of mobile applications can be supported by pure object-, service- and context-aware aspect-orientation. Our study has shown that CSLogicAJ can improve the modularization of context-aware applications and reduce anticipation of runtime adaptations when compared to other approaches

SensLAB Very Large Scale Open Wireless Sensor Network Testbed

International audienceThis paper presents a precise description of SensLAB: Very Large Scale Open Wireless Sensor Network Testbed that has been developed and deployed in order to allow the evaluation of scalable wireless sensor network protocols and applications. SensLAB's main and most important goal is to o er an accurate open access multi-users scienti c tool to support the design, development, tuning, and experimentation of real large-scale sensor network applications. The SensLAB testbed is composed of 1024 nodes and it is distributed among 4 sites. Two sites o er access to mobile nodes. Every sensor node is also able to be con gured as a sink node and can exchange data with any other sink node of the whole SensLAB testbed (locally or remotely) or any computer on the Internet. The hardware designed on purpose and software architectures that allow to reserve, con gure, deploy embedded software, boot wireless sensor nodes and gather experimental data and monitoring information are described in details. We also present short demonstration examples to illustrate the use of the SensLAB testbed

The AdCIM framework : extraction, integration and persistence of the configuration of distributed systems

[Resumen] Este resumen se compone de una introducción, que explica el enfoque y contexto de la Tesis, seguida de una sección sobre su organización en partes y capítulos. Después, sigue una enumeración de las contribuciones recogidas en ella, para finalizar con las conclusiones y trabajo futuro. Introducción Los administradores de sistemas tienen que trabajar con la gran diversidad de hardware y software existente en las organizaciones actuales. Desde el punto de vista del administrador, las infraestructuras homogéneas son mucho más sencillas de administrar y por ello más deseables. Pero, aparte de la dificultad intrínseca de mantener esa homogeneidad a la vez que progresa la tecnología y las consecuencias de estar atado a un proveedor fijo, la propia homogeneidad tiene riesgos; por ejemplo, las instalaciones en monocultivo son más vulnerables contra virus y troyanos, y hacerlas seguras requiere la introducción de diferencias aleatorias en llamadas al sistema que introduzcan diversidad artificial, una medida que puede provocar inestabilidad (ver Birman y Schneider. Esto hace la heterogeneidad en sí casi inevitable, y una característica de los sistemas reales difícil de obviar. Pero de hecho conlleva más complejidad. En muchas instalaciones, la mezcla de Windows y derivados de Unix es usual, ya sea en combinación o divididos claramente en clientes y servidores. Las tareas de administración en ambos sistemas son diferentes debido a las diferencias en ecosistema y modo de conceptualizar los sistemas informáticos acaecidas tras años de divergencia en interfaces, sistemas de configuración, comandos y abstracciones. A lo largo del tiempo ha habido muchos intentos de cerrar esa brecha, y algunos lo hacen emulando o versionando las herramientas Unix, probadas a lo largo de muchos años. Por ejemplo, la solución de Microsoft, Windows Services for Unix permite el uso de NIS, el Network File System (NFS), Perl, y el shell Korn en Windows, pero no los integra realmente en Windows, ya que está más orientado a la migración de aplicaciones. Cygwin soporta más herramientas, como Bash y las Autotools de GNU, pero se centra en la traslación directa a Windows de programas Unix basados en POSIX usando gcc. Outwit es un port muy interesante del conjunto de herramientas Unix que integra los pipelines de Unix en Windows y permite acceder al Registro, los drivers ODBC y al portapapeles desde los shells de Unix, pero los scripts desarrollados para este sistema no son usables directamente en sistemas Unix. Por lo tanto, la separación sigue a pesar de dichos intentos. En esta Tesis presentamos un framework, denominado AdCIM, para la administración de la configuración de sistemas heterogéneos. Como tal, su objetivo es integrar y uniformizar la administración de estos sistemas abstrayendo sus diferencias, pero al mismo tiempo ser flexible y fácil de adaptar para soportar nuevos sistemas rápidamente. Para lograr dichos objetivos la arquitectura de AdCIM sigue el paradigma de orientación a modelo, que propone el diseño de aplicaciones a partir de un modelo inicial, que es transformado en diversos ''artefactos'', como código, documentación, esquemas de base de datos, etc. que formarían la aplicación. En el caso de AdCIM, el modelo es CIM, y las transformaciones se efectúan utilizando el lenguaje declarativo XSLT, que es capaz de expresar transformaciones sobre datos XML. AdCIM realiza todas sus transformaciones con XSLT, excepto la conversión inicial de ficheros de texto plano a XML, hecha con un párser especial de texto a XML. Los programas XSLT, también denominados stylesheets, enlazan y transforman partes específicas del árbol XML de entrada, y soportan ejecución recursiva, formando un modelo de programación declarativo-funcional con gran potencia expresiva. El modelo elegido para representar los dominios de administración cubiertos por el framework es CIM (Common Information Model), un modelo estándar, extensible y orientado a objetos creado por la Distributed Management Task Force (DMTF). Usando esquemas del modelo CIM, los múltiples y distintos formatos de configuración y datos de administración son traducidos por la infraestructura de AdCIM en instancias CIM. Los esquemas CIM también sirven como base para generar formularios web y otros esquemas específicos para validación y persistencia de los datos. El desarrollo de AdCIM como un framework orientado al modelo evolucionó a partir de nuestro trabajo previo, que extraía datos de configuración y los almacenaba en un repositorio LDAP utilizando scripts Perl. En sucesivos trabajos se empezó a trabajar con la orientación a modelo y se demostró la naturaleza adaptativa de este framework, mediante adaptaciones a entornos Grid y a Wireless Mesh Networks. El enfoque e implementación de este framework son novedosos, y usa algunas tecnologías definidas como estándares por organizaciones internacionales como la IETF, la DMTF, y la W3C. Vemos el uso de dichas tecnologías como una ventaja en vez de una limitación en las posibilidades del framework. Su uso añade generalidad y aplicabilidad al framework, sobre todo comparado con soluciones ad-hoc o de propósito muy específico. A pesar de esta flexibilidad, hemos intentado en todo lo posible definir y concretar todos los aspectos de implementación, definir prácticas de uso adecuadas y evaluar el impacto en el rendimiento y escalabilidad del framework de la elección de las distintas tecnologías estándar

Design and development of a context sensitive rural development software application for eService provisioning

After more than a decade since South Africa realized the importance of Information and Communication Technology (ICT) and the role it can play to deliver services, the country is still confronted by a number of challenges challenges that hinder the implementation of a fully-fledged ICT-based system in a form of electronic government to better deliver services and information. While rural development remains as one of the country’s greatest concerns, ICT is among approaches and perspectives that are recognized for not only accelerating rural development but also for providing the country’s economic growth. This research was set to investigate approaches to implement ICT solutions for rural development and service provisioning in the context of electronic government. The research focused more on the technical skills to implement such ICT systems for the benefit of rural development and e-government stakeholders that have an interest in design and development of an integrated and interoperable solution to accelerate service delivery, especially in rural communities. A mixed methods approach was used throughout the research accompanied by an evolutionary prototyping to development the desired prototype. A study was then conducted to gain an understanding of the state and the needs of rural communities to date. The results of the study yielded a number of urbanized service providers that rural dwellers need to timeously visit to consume services. Scenarios to design and develop the intended prototypes were then drawn from these results. The overall implementation of the prototypes produced an integrated platform that allows multiple disparate systems to communicate, share and use information. The qualities of the prototype are what this research recommends to relevant to stakeholders in order to implement an integrated and interoperable e-government system that elevates rural development programs and service delivery