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Telecommunications networks are composed of functional layers acting in cascade. Quality of service (QoS) derives from the action of each layer that must assure a specific level of quality to the upper layer in terms of performance parameters. The action is called vertical QoS mapping and is provided through algorithms that compute the bandwidth necessary so to assure the requested QoS when information...
Multi-source streaming is essential for the design of a large-scale P2P streaming architecture. In this paper, we focus on improving the dependability of multi-source video streaming as an alternative to the more prevalent point-to-point streaming. We have designed and implemented a dynamic FEC (D-FEC) protocol for multi-source video streaming. Our D-FEC protocol has the ability to dynamically switch...
Delay Tolerant Networks (DTNs) are able to provide communication services in challenged networks where the end-to-end path between the source and destination does not exist. In order to increase the probability of delivery, DTN routing mechanisms may require nodes in the network to store and carry messages in their local buffer and replicate many copies. When the limited buffer is consumed, choosing...
In order to optimize the performance of wireless sensor networks, based on the boolean sensing model (BSM) many coverage preserving protocols have been proposed; however, BSM model is too idealistic to be maintained in many applications. Sensing range could be changed by environment factors such as the obstacle and weather condition. BSM based protocols can not achieve their design goals because of...
Time synchronization has become an important and well-studied issue in wireless sensor network (WSN). Because of the physical characteristics of WSN such as resource limitation, dynamicity, and randomicity, building an efficient and accurate time synchronization model is a challenge. Most existing time synchronization model use first-order or second order model to describe the time variance. However,...
Deny of service (DoS) detection problem is a common and annoying network difficulty, but for IEEE 802.11 standards it becomes even more troublesome. Addressing this issue, we introduce a new approach to promptly warn the user. The detection algorithm put forward, combines second generation of artificial immune systems, danger theory and multi-agent system. For the detection system, we used the dendritic...
Voice-over-IP protocols (e.g., SIP) are vulnerable to many types of attacks. One core challenge in preventing VoIP attacks is to assess the trustworthiness of the caller's identity. Further, spoofing attacks must be prevented by verifying that the call has been initiated by the user belonging to the caller's identity. In this paper, we propose to adapt a Web-of-Trust model to real-time communication...
We consider the problem of finding an optimal and adaptive timeslot scheduling algorithm for long cycle data in WIA-PA network (ATS-LCD), which focuses on hybrid mesh and star network topology and a feedback mechanism that can significantly reduce collisions among clusters. OPNET simulation results demonstrate that ATS-LCD significantly outperforms TDMA-over-CDMA and CSMA MAC protocols in terms of...
During the development of a distributed application, programmers usually involve many programs. These programs have different IP addresses and different ports. Sometimes, they even have a same port. For instance, in P2P environment, peers usually use the same port to communicate with each other. We often need tens of computers to develop such a distributed application. Unfortunately, not each one...
The ability to provide various application services introduces more traffic and therefore the problem of data traffic congestion in a VANET (Vehicular Ad-Hoc Network), and hence the QoS (Quality of Service) of the application deteriorates. This paper studies an adaptive PI rate-controller to improve/restore the QoS. The controller controls the source sending rate based on the instantaneous queue length...
Efficient dissemination of messages in a vehicular ad hoc network (VANET) still face many challenges in the current research scenario. This paper addresses the problem of redundant forwarding of messages that occur during broadcast and proposes an adaptive forwarding mechanism which controls the amount of redundant messages thereby improving message dissemination over a VANET. The mechanism will enable...
Massively Multiplayer Online Games and Virtual Worlds are among the most popular applications on the Internet. As player numbers increase, the limits of the currently dominant client/server architecture are becoming obvious. To overcome those limits, the research community has developed protocols for these so-called Distributed Networked Virtual Environments (DVEs) based on peer-to-peer technologies...
In this paper a framework and cognitive process behavior model for a novel type of adaptive data network was proposed. Furthermore, access network selection and admission control mechanisms are integrated into a procedure defined as access control. The access control mechanism is based on cognitive process, and enables all network elements involved to achieve self-awareness, self-configuration, and...
The convergent feature of traffic in wireless body area networks (WBANs) makes congestion in certain areas which are the place of events and/or the location of sensor nodes near a sink. Congestion brings packet loss, retransmission, and delay at the node and it also causes the consumption of additional energy. Therefore there is no doubt that congestion needs to be controlled efficiently. In this...
A model-driven testing method for network management interface was proposed in order to minimize the impact of changeful test requirement and diverse interface technologies, improve the test efficiency as well as lower test cost. This method was founded on testing models including test case model and test scenario model, which can be transformed and constructed from platform-independent model (PIM)...
Energy efficiency is a major concern in the design of wireless sensor networks (WSNs) and their communication protocols. As the radio transceiver typically accounts for a major portion of a WSN node's power consumption, researchers have proposed energy-efficient medium access (E2-MAC) protocols that switch the radio transceiver off for a major part of the time. Such protocols typically trade off energy-efficiency...
This paper proposes a semantic information integration approach for agent-based electronic markets based on ontology-based technology, improved by the application and exploitation of the trust relationships captured by the social networks. We intent face the problem of the growth of e-commerce using software agents to support both customers and suppliers in buying and selling products. The diversity...
Effective adaptation of error-control coding in a packet radio network requires certain statistics to be developed in the demodulator and decoder of the receiving radio during the reception of each packet. The statistics from one packet are employed to select the code for the next packet. The design and evaluation of cross-layer protocols that use such statistics typically require numerous simulations...
Statistics obtained during demodulation are used in a direct-sequence spread-spectrum packet radio network to govern the adjustment of transmitter power within the first few packets of a session. The statistics are also employed by an adaptive transmission protocol to select the modulation parameters and the rate of the error-control code for each packet. The power-adjustment protocol uses the statistics...
In ubiquitous computing environments, the software component model with semantic information and adaptation to satisfy various resources constraints and component interdependence is needed. This paper mainly presents an adaptive and semantic component model for an adaptive middleware. The model consists of an adaptive component model and a semantic virtual agent model. The contribution of our work...
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