Papers by Keyword: Quality of Service (QoS)

Abstract: Cloud computing is evolving as a realization of SoA in which IT resources are offered as services on a pay-as-you-go basis. But several functionally equivalent services are discovered, because of the exponential growth in the number of cloud providers and services. The best service can be selected by ranking all the discovered services using their network and other non-network QoS parameters, which is formulated as MCDM problem. In this paper, we proposed a hybrid approach for MCDM problem that contains AHP and PROMETHEE. AHP is used to investigate the structure of the service ranking problem and to determine the weights of the QoS criteria, and PROMETHEE method is applied for the final ranking. The results of evaluation demonstrate the effectiveness of the proposed hybrid method, and furthermore show the impact of network QoS parameters in the final service ranking.

Abstract: Integrating trunking multimedia services into LTE public networks is becoming an innovation and research focus. But several aspects have to be considered for providing effective multimedia services to trunking mobile users. In particular, in this work, we design a packet scheduler for real-time downlink communication, considering both the QoS and the priority of user equipment (UE). To this aim, we exploit an innovative approach based on discrete-time linear control (DTLC) theory to satisfy the QoS requirements and add the priority of UE to determine the priority order in which the services should be scheduled. The performance of the proposed scheme has been evaluated by theory and simulations. A comparison with recently proposed scheduling strategies has also been presented. Results have clearly shown that the proposed approach is able to greatly outperform the existing ones especially in the presence of real-time video flows.

Abstract: For a network control system (NCS) with redundancy structure, this paper designs a network scheduler, which can coordinate network load and support redundancy to enhance system availability, safety and reliability. Considering the Quality of Service (QoS) and the Quality of Control (QoC) to constitute the objective function of network resources scheduling, the scheduler uses fuzzy system to establish the network resource scheduling strategy, which dynamically decides communication channels of network control loops by calculating online and real-time scheduling. The scheduler can improve real-time performance and availability of the NCS, and quickly switch redundancy network under fault conditions to ensure reliability of the NCS. At last, the experiment results demonstrate that the proposed scheduler meets the requirements of the resource scheduling and redundancy network, and can effectively improve the performance of the NCS when network load increases.

Abstract: This paper analyzes several related parameters of multimedia data flow transmission with applied technology in wireless network environment and establishes simulation model in NS2, In view of the low bandwidth, the high error rate and the high delay of wireless networks, Through the simulation analysis of the different packet error rate, the compression quantization parameter, the length of GOP and packet for image quality based on the PSNR evaluation method respectively, the result of the simulation analysis provides the beneficial reference for the wireless network of more effectively in multimedia data transmission.

Abstract: For the grid workflow system include a large of candidate services, the activity scheduling in workflow’s ex-ecution base on quality of service (QoS) constraints can pro-vide optimal service for users. This paper established the QoS’s parameter system with applied technology of grid workflow, and introduced the each parameter’s calculation model of activity’s QoS, the grid work-flow’s QoS estimation method based on the basic flow control structures defined by the abstract grid workflow language (AGWL). The experimental results show that the calculation method in this paper can estimate stably QoS parameter values of grid workflow combining with the multi candidate services, and, can provide a reasonable basis for process scheduling based on QoS constraints.

Abstract: One of the choke point of AD HOC network is that the system hasnt resolved the problem of QOS in the MAC layer, the MAC layer QOS of AD HOC network is divided into two levels, one is flow level, and the other is node level. In order to solve QOS problem, this paper proposed a new algorithm IMSMAC, the algorithm use penalty function to optimize the value of different level of service in flow level, and use different priority backoff index to different node in node level. Analysis the throughput and delay of IMSMAC and DCF in NS2, the result showed that the high priority service have a certain degree of improvement in throughput and delay in IMSMAC algorithm.

Abstract: Despite of a collection of Quality of Service (QoS) guarantee protocols, no one is able to perform adaptively due to the application dependent nature of those proposed QoS provision algorithms. In this paper a new adaptive model, termed AHP-TOPSIS, is employed to evaluate the performance of two routing protocols DSR and DSDV, based on which the system is capable of switching to the optimal protocol adaptively. The efficiency of the AHP-TOPSIS model is validated by extensive simulations.

Abstract: Due to the further development in recent years, VoWLAN(VoIP over Wireless LAN) will achieve convergence with other service inevitably and has a higher requirement for network performance. Service focused on the whole converged network is different, so the measure of network status has different demands, we should set parameters reasonably and make it adaptive network in order to realize the optimization of network performance according to the current channel load level and distribution of service condition. Therefore, we can adjust the Contention Window(CW) dynamically, according to the slot utilization rate to estimate the channel load and the concept of backoff discontinuation rate. Simulation results prove that this scheme is simple and effective, largely improved QoS performance of the throughput and delay of each service.

Abstract: Quality of Service (QoS) routing is intent to find feasible routes according to QoS constraints and optimize utilization of whole network resources. In order to solve bandwidth-guaranteed QoS routing problem, a simple but effective routing algorithm based on precomputation scheme with load balancing consideration, is proposed. The algorithm is implemented and simulated using Network Simulator (NS2). Research results showed that the proposal can keep some links free from becoming bottlenecks earlier, avoid congestion caused by unbalanced traffic load distribution, and improve performance of IP backbone networks.

Abstract: In this paper, an ABC (Always Best Connected) supported QoS (Quality of Service) unicast routing scheme is proposed. In the proposed scheme, in order to overcome difficulties on accurately measuring network link parameter values and exactly expressing user QoS requirements, the knowledge of the fuzzy mathematics and probability theory is introduced, and the range is used to describe these parameters; both of the users utility and the network providers utility are computed, and gaming analysis is taken to deal with profits of both the user and the network provider; EDPGA (Elitist Distance-based Pareto Genetic Algorithm) is used to find the specific QoS unicast path with Pareto optimum under Nash Equilibrium among all parties utilities achieved or approached. While comparing with unicast routing scheme based on Dijkstra and the game theory based fuzzy unicast QoS routing scheme, simulation results show that this proposed scheme is both feasible and effective.