共查询到20条相似文献，搜索用时 312 毫秒
1.
为了满足OFDMA-WLAN系统下行通信中多用户的不同业务需求,提出一种基于公平性和QoS服务保障的资源分配算法.不同的QoS要求被转换成不同的速率要求来计算QoS满意等级;优化目标被修改为公平性驱动的优化函数以提供公平性保障;复杂的资源分配问题被划分为信道分配和功率分配问题,并通过二分图匹配和注水法得到分配结果.与其他算法相比,所提出的算法牺牲了较少的数据速率换取更高的公平性和QoS满意度.仿真结果表明所提算法具有保障QoS和公平性的能力,且在QoS、公平性和速率之间权衡折中时表现更好. 相似文献
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提出了一种能在承载多媒体业务的移动通信网络中提供较高服务质量保证的接入控制方法 .该方法将接入控制与带宽预留相结合 ,保证传输业务服务质量的要求 .仿真结果表明 ,与两种传统的接入控制算法相比 ,本文所提出的算法能够使强行中止概率降低 .该算法能用于未来多媒体通信系统中 相似文献
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简要介绍了博弈论的基本原理和非合作博弈功率控制模型,为了改进非合作博弈中终端的不公平性,将合作博弈引入到功率控制中来,使得系统中所有终端都工作在最佳的等信干比下,并推导出一个分布式基于合作博弈的功率控制算法.仿真表明,该算法明显提高了系统的性能,系统中终端具有相对较高的效用和较低的发射功率,还使得无线网络资源的使用更加合理和公平,同时算法拥有较好的收敛性. 相似文献
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WANG Yang ZHAN Yi-chun YU Shao-hua 《重庆大学学报(英文版)》2007,6(4):265-272
This paper investigates the routing among autonomous systems (ASs) with quality of service (QoS) requirements. To avoid the intractability of the problem, abstract QoS capability must be informed among ASs, because the routhing which constrained QoS has been proved to be nondeterministic polynomial-time (NP) hard even inside an AS. This paper employs the modified Dijkstra algorithm to compute the maximum bottleneck bandwidth inside an AS. This approach lays a basis for the AS-level switching capability on which interdomain advertisement can be performed. Furthermore, the paper models the aggregated traffic in backbone network with fractional Brownian motion (FBM), and by integrating along the time axis in short intervals, a good estimation of the distribution of queue length in the next short intervals can be obtained. The proposed advertisement mechanism can be easily implemented with the current interdomain routing protocols. Numerical study indicates that the presented scheme is effective and feasible. 相似文献
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基于语义与QoS全局感知的web服务组合 总被引：1，自引：0，他引：1
针对服务组合流程,提出了语义与QoS全局感知的服务组合.在全局语义匹配过程中,既考虑了全局匹配,又考虑了从QoS角度进行匹配.当对服务组合有全局语义满足及QoS约束要求时,在全局范围里选择满足整个服务组合流程的QoS约束和语义匹配度要求的具体服务集,并实现服务组合的优化解.建立了全局匹配的QoS模型及其评价方法,基于该模型及评价方法,采用遗传算法实现全局语义匹配度最大化及满足用户的QoS指标需求.实验结果和分析表明,基于语义与QoS感知的服务匹配算法是可行和有效的. 相似文献
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With the rapid growth of service scale, there are many services with the same functional properties but different non-functional
properties on the Internet. There have been some global optimizing service selection algorithms for service selection. However,
most of those approaches cannot fully reflect users’ preferences or are not fully suitable for large-scale services selection.
In this paper, an ant colony optimization (ACO) algorithm for the model of global optimizing service selection with various
quality of srevice (QoS) properties is employed, and a user-preference based large-scale service selection algorithm is proposed.
This algorithm aims at optimizing user-preferred QoS properties and selecting services that meet all user-defined QoS thresholds.
Experiment results prove that this algorithm is very efficient in this regard. 相似文献
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Partial transmit sequence(PTS)is a promising technique for peak-to-average power ratio(PAPR)reduction in orthogonal frequency division multiplexing(OFDM).While in optimal PTS,an exhaustive search for all combinations of phase factor sequences is required,this results in huge computation.In this paper,by introducing the orthogonal design,a phase factor sequences algorithm is proposed.The algorithm uses orthogonal table to gencrate phase factor sequences,and the regular PAPR computation result is then followed by the parameter estimation.The simulation result shows that the proposed algorithm reduces the computation notably and obtains a good PAPR performance approaching the optimal PTS. 相似文献
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Based on five scheduling types and their QoS requirements defined in IEEE 802.16e specification, this paper proposes a new scheduring algorithm for non-real-time or real-time multimedia services. Taking the performances of efficiency, fairness and complexity into consideration, the proposed algorithm enhances the efficiency of air interface resource at the expense of the short-time unfairness, but ensures the long-time fairness. Moreover, the proposed algorithm introduces an efficient QoS assurance mechanism, which implements the functions of congestion control, queuing management and traffic management. The simulation results based on a simplified traffic model show that the proposed algorithm guarantees better performances of efficiency and fairness than conventional algorithms, without increasing the algorithm complexity. Especially on the occasion of heavy-traffic requirement, the performance of efficiency and fairness can be improved by 50% at most. 相似文献
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We present an unequal decoding power allocation （UDPA） approach for minimization of the receiver power consumption subject to a given quality of service （QoS）, by exploiting data partitioning and turbo decoding. We assign unequal decoding power of forward error correction （FEC） to data partitions with different priority by jointly considering the source coding, channel coding and receiver power consumption. The proposed scheme is applied to H.264 video over additive white Gaussion noise （AWGN） channel, and achieves excellent tradeoff between video delivery quality and power consumption, and yields significant power saving compared with the conventional equal decoding power allocation （EDPA） approach in wireless video transmission. 相似文献
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指出传统蚁群算法在解决QoS单播路由选择问题时,受到时延和带宽的约束,为降低路由费用,容易出现陷入局部最优且收敛速度慢的现象。针对上述问题,提出一种基于精英策略的蚁群优化QoS单播路由算法,该算法利用蚁群算法原理,并引入精英策略。通过仿真模拟一个20节点的计算机网络QoS单播路由选择实例,并与传统蚁群优化(ACO)算法进行对比,仿真结果表明该算法是有效的。 相似文献
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Time allocation scheme in IEEE 802.15.3 TDMA mechanism 总被引：1，自引：0，他引：1
In network with a shared channel in TDMA mechanism, it is a core issue to effectively allocate channel time to provide service guarantees for flows with QoS requirements. This paper proposes a simple and efficient time allocation scheme called MES-ESRPT (MCTA at the End of Superframe-Enhanced Shortest Remaining Processing Time) for delay-sensitive VBR traffic in accordance with IEEE 802.15.3 standard. In this algorithm, PNC (piconet coordinator) allocates one MCTA (Management Channel Time Allocation) for each stream which is the process of communication at the end of superframe. During the MCTA period, each transmitter should report current fragments number of the first MSDU (MAC Service Data Unit) and the fragments number of the remainder MSDUs to PNC. In the next superframe, PNC firstly allocates part CTAs (Channel Time Allocation) for each stream based on the remainder fragments number of the first MSDU by SRPT rule, then allocates remainder CTAs for each stream based on all fragments number of remainder MSDUs by the same SRPT rule. Simulation results showed that our proposed MES-ESRPT method achieves significantly better performance in QoS for multimedia streams compared to the existing schemes. 相似文献
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龚小勇 《重庆职业技术学院学报》2007,16(3):152-154
服务质量(QoS)描述了服务满足消费者需求的能力,提供有保证的QoS是Web服务在商业应用中获得成功的关键。本文利用UDDI的外部分类架构,建立了描述Web服务QoS的一组分类tModel,并给出了服务提供者QoS指标的量化定理和Web服务QoS的实现过程。该方法不改变UDDI内部结构,能更好地与Web服务标准协议兼容,并易于实现。 相似文献
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An immune-tabu hybrid algorithm for thermal unit commitment of electric power systems 总被引：1，自引：0，他引：1
This paper presents a new method based on an immune-tabu hybrid algorithm to solve the thermal unit commitment （TUC） problem in power plant optimization. The mathematical model of the TUC problem is established by analyzing the generating units in modem power plants. A novel immune-tabu hybrid algorithm is proposed to solve this complex problem. In the algorithm, the objective function of the TUC problem is considered as an antigen and the solutions are considered as antibodies, which are determined by the affinity computation. The code length of an antibody is shortened by encoding the continuous operating time, and the optimum searching speed is improved. Each feasible individual in the immune algorithm （IA） is used as the initial solution of the tabu search （TS） algorithm after certain generations of IA iteration. As examples, the proposed method has been applied to several thermal unit systems for a period of 24 h. The computation results demonstrate the good global optimum searching performance of the proposed immune-tabu hybrid algorithm. The presented algorithm can also be used to solve other optimization problems in fields such as the chemical industry and the power industry. 相似文献
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针对多载波DSL系统在指定用户数据速率的情况下尽量降低传输功率,以降低对系统中其它设备的电磁干扰,提出了一种多用户比特加载算法.首先对该算法模型进行了分析,提出了数学公式,考虑了比特最高限额及功率最大值限制的情况,然后分析该问题的优化解的复杂度,最后在DSL系统环境下进行仿真,结果发现,该算法在2个用户的情况下与最优解几乎相同,比离散化的贪婪迭代算法性能要好,计算复杂度也较低. 相似文献
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MOU Yu-jie CAO Jian ZHANG Shen-sheng ZHANG Jian-hong 《浙江大学学报(A卷英文版)》2006,7(4):483-492
INTRODUCTION Web service technologies are immerging as a powerful vehicle for organizations that participate in Web based dynamic collaborations. An organization can publish its business processes as Web services to the Internet for potential customers to discover and use them. Compared with traditional fixed inter-orga- nization collaboration relationship, the Web-based dynamic collaboration brings service providers more customers and more profits, and enables consumers to search in a w… 相似文献
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INTRODUCTION Real-time video transport over wireless Internet faces many challenges due to the heterogeneous en- vironment including wireline and wireless networks. Fig.1 shows a typical end-to-end video transport in- volving wireline and wireless networks. The video transport may suffer from many problems such as wireline network congestion and wireless multi-path fading, resulting in high packet loss-rate, and causing severe video quality degradation. To maintain the optimal video quali… 相似文献
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KATSAGGELOS Aggelos K. 《浙江大学学报(A卷英文版)》2006,7(5):801-810
INTRODUCTION Video streaming is becoming one of the major driving forces of next generation wireless networks. For the currently deployed cellular networks, the practical data rates are not enough to support full rate, high quality video applications. As a result, many research efforts have been devoted to adapting video content to reconcile the conflict between the high demand of video quality and the limited wireless communication resources among users. A large body of literature utiliz… 相似文献
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基于组件Web应用程序的覆盖率准则和测试需求约简（英文） 总被引：1，自引：0，他引：1
为了更好地分析测试基于组件的Web应用,并抉择何时结束测试过程,提出了覆盖率准则的概念和测试需求约简的方法.首先,定义了4种覆盖率准则,并证明它们之间的包含关系.然后,使用一种转换算法将Web应用测试模型转换成一种可以约简测试需求集合的Web应用决策-决策图（WADD图）.最后,基于各种覆盖率准则,并通过分析图中各条边的等价和包含关系,约简测试需求集合.测试人员可以根据不同的测试环境需求选择不同测试需求集合.案例分析表明,在实际的Web应用中所定义的覆盖率准则确实存在线性包含关系.基于不同的测试覆盖率准则,测试需求集合平均可约简55%以上.随着覆盖率准则复杂度的提高,测试需求的规模也随之增大. 相似文献