International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / Today's complex implementations of integrated packet and circuit switched digital communications networks demand that the software used for controlling these systems be robust, fault tolerant, and capable of runtime recovery from all but the most severe of operational errors. The typical modern switched communications system includes the use of multiple circuit switches, each with potentially thousands of end-user interfaces. Further, these switches are often inter-connected to each other via high-capacity trunks. A single connection between two end-user interfaces often traverses a number of intermediate circuit switches in order to effect the end-to-end communications desired. In this complex, distributed environment, the establishment and dissolution of end-to-end user connections involve far more than simple binary connection states indicating the existence, or non-existence, of a link. More commonly, a single end-to-end connection requires multiple node links across multiple, heterogeneous interfaces. The command and control software used to establish, monitor, and dissolve these connections must be capable of dealing with errors which arise at any node along the way in a consistent and reliable manner. Most critically, the system software must be capable of maintaining an accurate, multi-level mapping of distributed resources' availability, allocation, and status. Further, the software must have the capability of "healing itself" during operational run-time when it can, and of accurately reporting the nature of inconsistencies caused by anomalous events that cannot be fixed on the fly. The Edwards Digital Switch (EDS), developed by CSTI, provides a case study of possible solutions, and potential pitfalls, that can arise in the design, development, and implementation of the controlling software in today's dynamic, distributed communications' system architectures.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 193-204). Also available via the Internet.

Abstract not available

Diplomarbeit--University of Brighton, 2000. / Includes bibliographical references. Also available via the World Wide Web.

Polymorphic type abstractions are proposed for constructing concurrent objects and layered peer-to-peer communication protocols, both of which exhibit inherently asynchronous behavior. The type abstractions are shown to be both expressive and efficient in the context of a statically typed object-oriented language. Where appropriate, the utility of the type abstractions is illustrated by demonstrating their usefulness in concurrent programming using the Actor model. The results of this work have direct applicability to problems in concurrent programming, distributed systems, and communication protocol architectures. An extensible, polymorphic type abstraction for structuring concurrent method execution in a strongly typed object-oriented language is introduced. The type abstraction is called a <i>polymorphic lambda type</i>. A lambda type is an abstraction for a procedure that is based in part on λ-abstraction in the λ-calculus. The lambda type is a key component of a concurrent object model that allows methods defined in a class to be instantiated as <i>lambda objects</i>. Lambda objects are used to represent some aspect of behavior and they represent a first-class execution environment. The first-class nature of lambda objects facilitates the construction of more powerful computational abstractions, primarily those requiring 'asynchronous interaction and concurrent execution. Through a series of refinements, lambda objects are shown to be as expressive as traditional procedures with little extra cost for call setup and invocation. Concurrent objects require synchronization control. A type abstraction called a <i>behavior set</i> is introduced for specifying synchronization constraints in a strongly typed concurrent object-oriented language with Actor-style concurrency semantics. The behavior set abstraction offers a solution to structuring synchronization control that coexists with an inheritance mechanism, thereby avoiding the inheritance anomaly. / Ph. D.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Stellenbosch University and the Katholieke Universiteit Leuven has a joint undertaking to develop a satellite communications payload. The goals of the project are: to undertake research and expand knowledge in the area of dynamically configurable antenna beam forming, to prove the viability of this research for space purposes and to demonstrate the feasibility of the development in a practical application. The practical application is low Earth orbit satellite communication system for applications in remote monitoring. Sensor data will be uploaded to the satellite, stored and forwarded to a central processing ground station as the satellite passes over these ground stations. The system will utilise many low-cost ground sensor stations to collect data and distribute it to high-end ground stations for processing. Applications of remote monitoring systems are maritime- and climate change monitoring- and tracking. Climate change monitoring allows inter alia, for the monitoring of the effects and causes of global warming. The Katholieke Universiteit Leuven is developing a steerable antenna to be mounted on the satellite. Stellenbosch University is developing the communications payload to steer and use the antenna. The development of the communications protocol stack is part of the project. The focus of this work is to implement the application layer protocol, which handles all file level communications and also implements the communications strategy. The application layer protocol is called the Satellite Communications Software System (SCSS). It handles all high level requests from ground stations, including requests to store data, download data, download log files and upload configuration information. The design is based on a client-server model, with a Station Server and Station Handler. The Station Server schedules ground stations for communication and creates a Station Handler for each ground station to handle all ground station requests. During the design, all file formats were defined for efficient ground station-satellite communications and system administration. All valid ground station requests and handler responses were also defined. It was also found that the system may be made more efficient by scheduling ground stations for communications, rather than polling each ground station until one responds. To be able to schedule ground station communications, the times when ground stations will come into view of the satellite have to be predicted. This is done by calculating the positions of the Satellite and ground stations as functions of time. A simple orbit propagator was developed to predict the satellite distance and to ease testing and integration with the communications system. The times when a ground station will be within range of the satellite were then predicted and a scheduling algorithm developed to minimise the number of ground stations not able to communicate. All systems were implemented and tested. The SCSS executing on the Satellite was developed and tested on the satellite on-board computer. Embedded implementations possess strict resource limitations, which were taken into account during the development process. The SCSS is a multi-threaded system that makes use of thread cancellation to improve responsiveness. / AFRIKAANSE OPSOMMING: Die Universiteit van Stellenbosch ontwerp tans ’n satelliet kommunikasieloonvrag in samewerking met die Katolieke Universiteit van Leuven. Die doel van die projek is om navorsing te doen oor die lewensvatbaarheid van dinamies verstelbare antenna bundelvorming vir ruimte toepassings, asook om die haalbaarheid van hierdie navorsing in die praktyk te demonstreer. Die praktiese toepassing is ’n satellietkommunikasiestelsel vir afstandsmonitering, wat in ’n Lae-Aarde wentelbaan verkeer. Soos die satelliet in sy wentelbaan beweeg, sal sensor data na die satelliet toe gestuur, gestoor en weer aangestuur word. Die stelsel gebruik goedkoop sensorgrondstasies om data te versamel en aan te stuur na kragtiger grondstasies vir verwerking. Afstandsmoniteringstelsels kan gebruik word om klimaatsverandering, sowel as die posisie van skepe en voertuie, te monitor. Deur oa. klimaatsveranderinge te dokumenteer, kan gevolge en oorsake van globale verhitting gemonitor word. Die Katholieke Universiteit van Leuven is verantwoordelik vir die ontwerp en vervaardiging van die satelliet antenna, terwyl die Universiteit van Stellenbosch verantwoordelik is vir die ontwerp en bou van die kommunikasie loonvrag. ’n Gedeelte van hierdie ontwikkeling sluit die ontwerp en implementasie van al die protokolle van die kommunikasieprotokolstapel in. Dit fokus op die toepassingsvlak protokol van die protokolstapel, wat alle leêrvlak kommunikasie hanteer en die kommunikasiestrategie implementeer. Die toepassingsvlaksagteware word die Satellietkommunikasie sagtewarestelsel (SKSS) genoem. Die SKSS is daarvoor verantwoordelik om alle navrae vanaf grondstasies te hanteer. Hierdie navrae sluit die oplaai en stoor van data, die aflaai van data, die aflaai van logs en die oplaai van konfigurasie inligting in. Die ontwerp is op die standaard kliënt-bediener model gebasseer, met ’n stasiebediener en ’n stasiehanteerder. Die stasiebediener skeduleer die tye wanneer grondstasies toegelaat sal word om te kommunikeer en skep stasiehanteerders om alle navrae vanaf die stasies te hanteer. Gedurende die ontwerp is alle leêrformate gedefinieer om doeltreffende adminstrasie van die stelsel, asook kommunikasie tussen grondstasies en die satelliet te ondersteun. Alle geldige boodskappe tussen die satelliet en grondstasies is ook gedefnieer. Daar is gevind dat die doeltreffendheid van die stelsel verhoog kan word deur die grondstasies wat wil kommunikeer te skeduleer, eerder as om alle stasies te pols totdat een reageer. Om so ’n skedule op te stel, moet die tye wanneer grondstasies binne bereik van die satelliet gaan wees voorspel word. Hierdie voorspelling is gedoen deur die posisies van die satelliet en die grondstasies as funksies van tyd te voorspel. ’n Eenvoudige satelliet posisievoorspeller is ontwikkel om toetsing en integrasie met die SKSS te vergemaklik. ’n Skeduleringsalgoritme is toe ontwikkel om die hoeveelheid grondstasies wat nie toegelaat word om te kommunikeer nie, te minimeer. Alle stelsels is geimplementeer en getoets. Die SKSS, wat op die satelliet loop, is ontwikkel en getoets op die satelliet se aanboord rekenaar. Die feit dat ingebedde stelsels oor baie min hulpbronne beskik, is in aanmerking geneem gedurende die ontwikkeling en implementasie van die SKSS. Angesien die SKSS ’n multidraadverwerkingsstelsel is, word daar van draadkansellasie gebruik gemaak om die stelsel se reaksietyd te verbeter.

The purpose of Presentations World Wide System (PWWS) is to allow students to view a live presentation through an Internet browser and allow the instructor to have control over the presentation.

The purpose of this study was to develop a Point Of Sale system which helps owners to cut restaurant losses, improve customer service, reduce employee mistakes, and increase profitability. mOrder-Servers is touch screen oprerated at the point of sale, It has an easy to follow screen layout, and the simplicity of a windows based interface.

La perte de conjoints et d’amis, la réduction progressive de leur mobilité et l’éloignement de plus en plus fréquent des enfants, plongent souvent les personnes âgées dans un isolement qui peut générer des dépressions qui ont à leur tour un impact négatif sur la santé. Des études médicales ont même démontré que l’isolement social augmente le risque de mortalité des personnes âgées. Alors que de nombreux programmes de recherche s’intéressent à développer une variété de solutions technologiques liées à la fragilité physique et/ou cognitive des personnes âgées pour qu’ils puissent rester le plus longtemps possible à domicile, nous nous intéressons à leur fragilité sociale qui limite leurs capacités à rester en contact avec la société. Nous émettons l’hypothèse que les technologies de l’information ont un rôle important à jouer pour apporter une solution à l’isolement social des personnes âgées. Mais concevoir des services adaptés et s’assurer de leur appropriation restent des questions ouvertes, auxquelles nous tentons de proposer des réponses, à la fois au niveau méthodologique et instrumental. Nous présentons une démarche de conception de services pour les personnes âgées, qui s’appuie sur la participation des futurs utilisateurs dans le cadre d’un «Living Lab». Nous illustrons cette démarche grâce à notre participation à un projet européen dont l’objectif est de développer des applications de télévision sociale pour contribuer au développement des interactions sociales entre pairs / Encouraging seniors to stay at home as long as possible is associated with a higher risk of social isolation. Extensive researches have established the strong relationship between social isolation and health, considering social engagement as an important component influencing psychological well-being and self-esteem of elderly people. In other words, aging well at home cannot be reduced to the management of physical and cognitive frailties and technologies should also tackle the quality of life of the elderly by fostering their social interactions especially for those who are living alone. We postulate that ICTs could alleviate elderly loneliness, in order to cope with their social frailty. However, designing appropriate services and ensure their adoption by the elderly remain open questions, which we try to provide answers at both methodological and instrumental level. We propose an approach to design services for the elderly based on the participation of the future users as part of a "Living Lab". We illustrate this approach by our participation in a European project aiming at developing and evaluating Social TV services. The objective is to foster social interactions among peers to enhance or restore social ties, with the goal of increasing psychological well-being and self-esteem of the elderly living alone