Building Interactive Distributed Applications in C++ with The Programmers\u27 Playground

The objective of The Programmers\u27 Playground, described in this manual, is to provide a development environment and underlying support for end-user construction of distributed multimedia applications from reusable self-describing software components. Playground provides a set of software tools and a methodology for simplifying the design and construction of applications that interact with each other and with people in a distributed computer system. This manual explains how to write interactive distributed applications using Playground. The only background necessary to get started is an understanding of basic data structures and control constructs in C++. If you already know C++, then with the tools provided by Playground, you will be able to write distributed applications without learning a new programming language and without needing to learn about how communication works in a distributed system

The Programmers\u27 Playground: I/O Abstraction for Heterogeneous Distributed Systems

I/O abstraction is offered as a new high-level approach to interprocess communication. Functional components of a concurrent system are written as encapsulated modules that act upon local data structures, some of which may be published for external use. Relationships among modules are specified by logical connections among their published data structures. Whenever a module updates published data, I/O takes place implicitly according to the configuration of logical connections. The Programmer\u27s Playground, a software library and run-time system supporting I/O abstraction, is described. Design goals include high-level communication among programs written in multiple programming languages and the uniform treatment of discrete and continuous data types. Support for the development of distributed multimedia applications is the motivation for the work

Komponentteknologi for distribuert media journalering

The ever increasing access to computers with multimedia and good communication facilities calls for better and more complex services. Distance education, video conferences and distributed medical treatment shows that cooperation between people is also carried out on the Internet. Many people utilize the potentials of multimedia computers for developing new distributed solutions in which media analysis is applied. A distributed surveillance system can for example find the number of individuals in a building – a system much used in banks and other buildings in need of strong security measures. This displays a need of a general framework for content analysis of media. Distributed Media Journaling (DMJ) is a project at the University of Oslo that has defined an architecture to support journaling of media in distributed systems. Media journaling is an extended concept for involving real time content analysis and media annotation. The architecture will support communication, distribution, migration, modularity, flexibility and reconfiguration in journaling of media. In this report, a prototype which implements some of the components in the DMJ architecture is developed to see if the above-mentioned requirements can be supported. It is especially the demand for a component model, the communication between the components and the migration that will be elaborated on in this report. The prototype is developed with the technologies Voyager Universal ORB and Message Bus (MBus). Voyager supports the component model and mobility with mobile agents. MBus supports exchange of messages between the loosely connected components with IP multicast, and does meet the communication requirements in an eventbroker. Video is sent as Real-time Transfer Protocol (RTP) data and is analyzed by the use of Java Media Framework (JMF) in the analysis components. The results show that the migration of the analysis components in the network is faster than starting a new component. Nevertheless, the difference is small as JMF doesn’t support serializing of the processing object. It also turns out that it takes long time to load the classes in the Java Virtual Machine (JVM). The migration in itself does not take much time as the size of the file is relatively small. To sum up, the implementation of the prototype shows that all requirements for the DMJ framework can be supported by the chosen component technology

Multimedia Teleservices Modelled with the OSI Application Layer Structure

This paper looks into the communications capabilities that are required by distributed multimedia applications to achieve relation preserving information exchange. These capabilities are derived by analyzing the notion of information exchange and are embodied in communications functionalities. To emphasize the importance of the users' view, a top-down approach is applied. The (revised) OSI Application Layer Structure (OSI-ALS) is used to model the communications functionalities and to develop an architecture for composition of multimedia services with these functionalities. This work may therefore be considered an exercise to evaluate the suitability of OSI-ALS for composition of multimedia teleservices

Heterogeneous component interactions: Sensors integration into multimedia applications

Resource-constrained embedded and mobile devices are becoming increasingly common. Since few years, some mobile and ubiquitous devices such as wireless sensor, able to be aware of their physical environment, appeared. Such devices enable proposing applications which adapt to user's need according the context evolution. It implies the collaboration of sensors and software components which differ on their nature and their communication mechanisms. This paper proposes a unified component model in order to easily design applications based on software components and sensors without taking care of their nature. Then it presents a state of the art of communication problems linked to heterogeneous components and proposes an interaction mechanism which ensures information exchanges between wireless sensors and software components

Desktop multimedia environments to support collaborative distance learning

Desktop multimedia conferencing, when two or more persons can communicate among themselves via personal computers with the opportunity to see and hear one another as well as communicate via text messages while working with commonly available stored resources, appears to have important applications to the support of collaborative learning. In this paper we explore this potential in three ways: (a) through an analysis of particular learner needs when learning and working collaboratively with others outside of face-to-face situations; (b) through an analysis of different forms of conferencing environments, including desktop multimedia environments, relative to their effectiveness in terms of meeting learner needs for distributed collaboration; and (c) through reporting the results of a formative evaluation of a prototype desktop multimedia conferencing system developed especially for the support of collaborative learning. Via these analyses, suggestions are offered relating to the functionalities of desktop multimedia conferencing systems for the support of collaborative learning, reflecting new developments in both the technologies available for such systems and in our awareness of learner needs when working collaboratively with one other outside of face-to-face situations

Improving perceptual multimedia quality with an adaptable communication protocol

Copyrights @ 2005 University Computing Centre ZagrebInnovations and developments in networking technology have been driven by technical considerations with little analysis of the benefit to the user. In this paper we argue that network parameters that define the network Quality of Service (QoS) must be driven by user-centric parameters such as user expectations and requirements for multimedia transmitted over a network. To this end a mechanism for mapping user-oriented parameters to network QoS parameters is outlined. The paper surveys existing methods for mapping user requirements to the network. An adaptable communication system is implemented to validate the mapping. The architecture adapts to varying network conditions caused by congestion so as to maintain user expectations and requirements. The paper also surveys research in the area of adaptable communications architectures and protocols. Our results show that such a user-biased approach to networking does bring tangible benefits to the user

Design of a shared whiteboard component for multimedia conferencing

This paper reports on the development of a framework for multimedia applications in the domain of tele-education. The paper focuses on the protocol design of a specific component of the framework, namely a shared whiteboard application. The relationship of this component with other components of the framework is also discussed. A salient feature of the framework is that it uses an advanced ATM-based network service. The design of the shared whiteboard component is considered representative for the design as a whole, and is used to illustrate how a flexible protocol architecture utilizing innovative network functions and satisfying demanding user requirements can be developed

An Open Framework for Integrating Widely Distributed Hypermedia Resources

The success of the WWW has served as an illustration of how hypermedia functionality can enhance access to large amounts of distributed information. However, the WWW and many other distributed hypermedia systems offer very simple forms of hypermedia functionality which are not easily applied to existing applications and data formats, and cannot easily incorporate alternative functions which would aid hypermedia navigation to and from existing documents that have not been developed with hypermedia access in mind. This paper describes the extension to a distributed environment of the open hypermedia functionality of the Microcosm system, which is designed to support the provision of hypermedia access to a wide range of source material and application, and to offer straightforward extension of the system to incorporate new forms of information access