Development of an advanced web application for managing videoconference

El objetivo del proyecto es realizar un cliente para videoconferencias de alta definición basado en Web. Se ha utilizado SIP como protocolo de señalización (establecimiento, finalización) de videoconferencias, para la gestión la lista de los contactos, la presencia, y la negociación de las capacidades multimedia.Existen numerosas aplicaciones que ofrecen al usuario la posibilidad de realizar videoconferencias en alta definición sobre Internet. Estas aplicaciones centran sus esfuerzos en la transmisión de contenido de alta calidad sobre Internet, pero dejan sin resolver la gestión del establecimiento, finalización de llamadas, aceptación, rechazo de invitaciones, suscripción y recepción de notificaciones del servicio de presencia (aparición de usuarios, cambios de estado, etc). El objetivo del proyecto es realizar un cliente para videoconferencias de alta definición basado en Web. Se ha utilizado SIP como protocolo de señalización (establecimiento, finalización) de videoconferencias, para la gestión la lista de los contactos, la presencia, y la negociación de las capacidades multimedia La aplicación desarrollada permite que, un usuario a partir de una web, sea capaz de ver todos los usuarios conectados al servicio, conocer sus características y poder establecer videoconferencias de alta calidad, utilizando el entorno de videoconferencia negociado (por ejemplo dvts, ultragrid). La aplicación actúa como un gateway HTTP-SIP, traduciendo las peticiones SIP a peticiones HTTP y viceversa. Las peticiones HTTP son enviadas hacia el cliente para que la trate y realice los cambios necesarios en la interfaz web y en su modelo de datos. La interfaz de web del usuario se ha desarrollado con Google Web Toolkit, un toolkit de Google para el desarrollo de aplicaciones AJAX en lenguaje de programación Java. El servidor se comunica con tres módulos. Con el mundo SIP para la señalización de videoconferencia, con el agente de presencia para gestionar la lista y con el cliente AJAX para comunicarse con los usuarios de la aplicación. El proyecto explica las fases de definición de requerimientos, diseño y arquitectura de la aplicación. Expone el estado del arte de las tecnologías y comenta algunos detalles de la implementación, finalizando con una planificación temporal y unos resultados finales del proyecto

Two Steps Towards Kairos-Awareness

This thesis describes a research inspired by a concept of the classical discipline of rhetoric: kairos, the right moment to deliver a message in order to maximize its effect. The research followed two threads that, ultimately, lead to the same ending: the maximization of the potential of technology to deliver the right interaction at the right time. The first research thread is an operationalization of the concept of kairos. It entailed the development of EveWorks and EveXL, a framework for capturing daily life events in mobile devices and a domain-specific language to express them, respectively. The largely extended use of mobile devices and their proximity with their owners offers exceptional potential for capturing opportunity for interaction. Leveraging on this potential, the EveWorks-EveXL dyad was developed to allow mobile application programmers to specify the precise delivery circumstances of an interaction in order to maximize its potential, i.e., to specify its kairos. Contrasting to most event processing engines found in the literature that implement data-based event models, the EveWorks-EveXL dyad proposes a model based on temporality, through the articulation of intervals of time. This is a more natural way of representing a concept as broad as “daily life events” since, across cultures, temporal concepts like duration and time intervals are fundamental to the way people make sense of their experience. The results of the present work demonstrate that the EveWorks-EveXL dyad makes for an adequate and interesting way to express contextual events, in a way that is “closer” to our everyday understanding of daily life. Ultimately, in user centered applications, kairos can be influenced by the user’s emotional state, thereby making emotion assessment relevant. Addressing this, as well as the growing interest in the topic of emotions by the scientific community, the second research thread of the present thesis led to the development of the CAAT, a widget designed to perform quick and reliable assessments of affective states – a paramount task in a variety of scientific fields, including HCI. While there are already a number of tools for this purpose, in psychology, emotion assessments are largely conducted through the use of pen-and-paper questionnaires applied after the affective experience has occurred. As emotional states vary significantly over time, this entails the loss of important details, warranting the need for immediate, in situ, measurements of affect. In line with this requirement, the CAAT enables quick emotion assessment in a reliable fashion, as attested by the results of then validation studies conducted in order to assess its overall viability along relevant dimensions of usability and psychometrics. As such, aside from being a good fit for longitudinal studies and applications whenever the quick assessment of emotions is required, the CAAT has the potential to be integrated as one of EveWorks’ sensors to enhance its ability to find that sometimes elusive opportunity for interaction, i.e., their kairos. In this way, it becomes apparent how the two threads of research of the current work may be intertwined into a consolidated contribution to the HCI field

A Hierarchical Filtering-Based Monitoring Architecture for Large-scale Distributed Systems

On-line monitoring is essential for observing and improving the reliability and performance of large-scale distributed (LSD) systems. In an LSD environment, large numbers of events are generated by system components during their execution and interaction with external objects (e.g. users or processes). These events must be monitored to accurately determine the run-time behavior of an LSD system and to obtain status information that is required for debugging and steering applications. However, the manner in which events are generated in an LSD system is complex and represents a number of challenges for an on-line monitoring system. Correlated events axe generated concurrently and can occur at multiple locations distributed throughout the environment. This makes monitoring an intricate task and complicates the management decision process. Furthermore, the large number of entities and the geographical distribution inherent with LSD systems increases the difficulty of addressing traditional issues, such as performance bottlenecks, scalability, and application perturbation. This dissertation proposes a scalable, high-performance, dynamic, flexible and non-intrusive monitoring architecture for LSD systems. The resulting architecture detects and classifies interesting primitive and composite events and performs either a corrective or steering action. When appropriate, information is disseminated to management applications, such as reactive control and debugging tools. The monitoring architecture employs a novel hierarchical event filtering approach that distributes the monitoring load and limits event propagation. This significantly improves scalability and performance while minimizing the monitoring intrusiveness. The architecture provides dynamic monitoring capabilities through: subscription policies that enable applications developers to add, delete and modify monitoring demands on-the-fly, an adaptable configuration that accommodates environmental changes, and a programmable environment that facilitates development of self-directed monitoring tasks. Increased flexibility is achieved through a declarative and comprehensive monitoring language, a simple code instrumentation process, and automated monitoring administration. These elements substantially relieve the burden imposed by using on-line distributed monitoring systems. In addition, the monitoring system provides techniques to manage the trade-offs between various monitoring objectives. The proposed solution offers improvements over related works by presenting a comprehensive architecture that considers the requirements and implied objectives for monitoring large-scale distributed systems. This architecture is referred to as the HiFi monitoring system. To demonstrate effectiveness at debugging and steering LSD systems, the HiFi monitoring system has been implemented at the Old Dominion University for monitoring the Interactive Remote Instruction (IRI) system. The results from this case study validate that the HiFi system achieves the objectives outlined in this thesis

Proceedings of the 1994 Monterey Workshop, Increasing the Practical Impact of Formal Methods for Computer-Aided Software Development: Evolution Control for Large Software Systems Techniques for Integrating Software Development Environments

Office of Naval Research, Advanced Research Projects Agency, Air Force Office of Scientific Research, Army Research Office, Naval Postgraduate School, National Science Foundatio

Feature interaction in composed systems. Proceedings. ECOOP 2001 Workshop #08 in association with the 15th European Conference on Object-Oriented Programming, Budapest, Hungary, June 18-22, 2001

Feature interaction is nothing new and not limited to computer science. The problem of undesirable feature interaction (feature interaction problem) has already been investigated in the telecommunication domain. Our goal is the investigation of feature interaction in componet-based systems beyond telecommunication. This Technical Report embraces all position papers accepted at the ECOOP 2001 workshop no. 08 on "Feature Interaction in Composed Systems". The workshop was held on June 18, 2001 at Budapest, Hungary

Analysis domain model for shared virtual environments

The field of shared virtual environments, which also encompasses online games and social 3D environments, has a system landscape consisting of multiple solutions that share great functional overlap. However, there is little system interoperability between the different solutions. A shared virtual environment has an associated problem domain that is highly complex raising difficult challenges to the development process, starting with the architectural design of the underlying system. This paper has two main contributions. The first contribution is a broad domain analysis of shared virtual environments, which enables developers to have a better understanding of the whole rather than the part(s). The second contribution is a reference domain model for discussing and describing solutions - the Analysis Domain Model

Development of an advanced web application for managing videoconference

El objetivo del proyecto es realizar un cliente para videoconferencias de alta definición basado en Web. Se ha utilizado SIP como protocolo de señalización (establecimiento, finalización) de videoconferencias, para la gestión la lista de los contactos, la presencia, y la negociación de las capacidades multimedia.Existen numerosas aplicaciones que ofrecen al usuario la posibilidad de realizar videoconferencias en alta definición sobre Internet. Estas aplicaciones centran sus esfuerzos en la transmisión de contenido de alta calidad sobre Internet, pero dejan sin resolver la gestión del establecimiento, finalización de llamadas, aceptación, rechazo de invitaciones, suscripción y recepción de notificaciones del servicio de presencia (aparición de usuarios, cambios de estado, etc). El objetivo del proyecto es realizar un cliente para videoconferencias de alta definición basado en Web. Se ha utilizado SIP como protocolo de señalización (establecimiento, finalización) de videoconferencias, para la gestión la lista de los contactos, la presencia, y la negociación de las capacidades multimedia La aplicación desarrollada permite que, un usuario a partir de una web, sea capaz de ver todos los usuarios conectados al servicio, conocer sus características y poder establecer videoconferencias de alta calidad, utilizando el entorno de videoconferencia negociado (por ejemplo dvts, ultragrid). La aplicación actúa como un gateway HTTP-SIP, traduciendo las peticiones SIP a peticiones HTTP y viceversa. Las peticiones HTTP son enviadas hacia el cliente para que la trate y realice los cambios necesarios en la interfaz web y en su modelo de datos. La interfaz de web del usuario se ha desarrollado con Google Web Toolkit, un toolkit de Google para el desarrollo de aplicaciones AJAX en lenguaje de programación Java. El servidor se comunica con tres módulos. Con el mundo SIP para la señalización de videoconferencia, con el agente de presencia para gestionar la lista y con el cliente AJAX para comunicarse con los usuarios de la aplicación. El proyecto explica las fases de definición de requerimientos, diseño y arquitectura de la aplicación. Expone el estado del arte de las tecnologías y comenta algunos detalles de la implementación, finalizando con una planificación temporal y unos resultados finales del proyecto