In this paper, efficient power allocation strategies for ARQ protocols operating in wireless environments are studied. Power is optimally adapted by the transmitter based on channel state information (CSI) obtained through feedback, while guaranteeing quality-of-service (QOS) constraints such as average throughput or average delay. The power policies adopted for basic ARQ protocols, such as Sto...

Quality of service capability of input queued packet switches is investigated. A packet transfer scheduling problem is formulated whereby each input-output pair is scheduled for packet transfers by regularly spaced deadlines, in compliance with a speciied data rate. Suitable applications include ATM networks and satellite switched TDMA systems that support periodic traac with delay guarantees. ...

In this paper, we present a system called DONOW (Database on Network of Workstation), that is an example of an implementation and maintenance of a low cost distributed database without performances penalties. The system has a three tier architecture based on a client, a service and a data layer. The client layer allows local and remote users to interact with the system through a Java user frien...

OBJECTIVE The goal of this work is to improve the usability of a non-rigid registration software for medical images. METHOD We have built a registration grid service in order to use the interactivity of a visualization workstation and the computing power of a cluster. On the user side, the system is composed of a graphical interface that interacts in a complex and fluid manner with the regist...

Research in this paper is focused on the modeling and simulation for distribution service network (DSN) of comprehensive passenger transport hub (CPTH). Firstly, based on the theory and method of complex network, the conception of DSN is proposed. Secondly, the model of DSN is build which consists of distribution entity topology network, distribution transport function network and distribution ...

The measurement of transit performance represents a very useful tool for ensuring continuous increase of the quality of the delivered transit services, and for allocating resources among competing transit agencies. Transit service quality can be evaluated by subjective measures based on passengers’ perceptions, and objective measures represented by disaggregate performance measures expressed as...

Many measurement studies showed that network traffic usually exhibits self-similar nature, meanwhile, wireless fading channels lead to the time-variant service rates of network nodes. Compared with classical queuing systems with Markov sources or constant service rates, the queuing system with self-similar input in a wireless fading channel is more complicated, and it is very difficult to obtai...

This paper demonstrates a distributed on-line service selection(probe/access) scheme: optimal stopping web service selection scheme based on the rate of return problem from optimal stopping theory. There are three differences between our scheme and the conventional schemes. Firstly, it does not need to probe all web services, and only probe a few web services. Secondly, our scheme focuses on ma...

With advances in IP and multimedia technologies, various multimedia services such as video streaming, videophones, and videoconferencing services are being developed and provided. Properly evaluating and managing users’ perceptions of multimedia quality of service (QoS) to provide comfortable multimedia services is important because their performances are not generally guaranteed in present IP ...

In this paper, we introduce recent advances of a speech retrieval web service, PodCastle, that collects and amplifies voluntary contributions by anonymous users. Our goal is to provide users with a public web service based on speech recognition and crowdsourcing so that they can experience state-of-the-art speech recognition performance through a useful service. PodCastle enables users to find ...