In this paper, we have used the distributed mean value analysis (DMVA) technique with the help of random observe property (ROP) and palm probabilities to improve the network queuing system throughput. In such networks...In this paper, we have used the distributed mean value analysis (DMVA) technique with the help of random observe property (ROP) and palm probabilities to improve the network queuing system throughput. In such networks, where finding the complete communication path from source to destination, especially when these nodes are not in the same region while sending data between two nodes. So, an algorithm is developed for single and multi-server centers which give more interesting and successful results. The network is designed by a closed queuing network model and we will use mean value analysis to determine the network throughput (b) for its different values. For certain chosen values of parameters involved in this model, we found that the maximum network throughput for β≥0.7?remains consistent in a single server case, while in multi-server case for β≥ 0.5?throughput surpass the Marko chain queuing system.展开更多
To reduce the interference among small cells of Ultra-Dense Networks(UDN),an improved Clustering-Assisted Resource Allocation(CARA)scheme is proposed in this paper.The proposed scheme is divided into three steps.First...To reduce the interference among small cells of Ultra-Dense Networks(UDN),an improved Clustering-Assisted Resource Allocation(CARA)scheme is proposed in this paper.The proposed scheme is divided into three steps.First,an Interference-Limited Clustering Algorithm(ILCA)based on interference graph corresponding to the interference relationship between Femtocell Base Stations(FBSs),is proposed to group FBSs into disjoint clusters,in which a pre-threshold is set to constrain the sum of interference in each cluster,and a Cluster Head(CH)is selected for each cluster.Then,CH performs a twostage sub-channel allocation within its associated cluster,where the first stage assigns one sub-channel to each user of the cluster and the second stage assigns a second sub-channel to some users.Finally,a power allocation method is designed to maximize throughput for a given clustering and sub-channel configuration.Simulation results indicate that the proposed scheme distributes FBSs into each cluster more evenly,and significantly improves the system throughput compared with the existing schemes in the same scenario.展开更多
The efficient use of energy is an important performance metric to extend the lifetime of wireless sensor networks. Since major energy consumption of node is due to its transceiver, the design of MAC protocol plays a v...The efficient use of energy is an important performance metric to extend the lifetime of wireless sensor networks. Since major energy consumption of node is due to its transceiver, the design of MAC protocol plays a vital role in sensor network design. In cluster based sensor networks, due to the different functions of member node and cluster head node, the usage of common MAC protocol results increased energy consumption. To overcome this problem, a novel energy efficient hybrid MAC protocol (EEHMAC) for cluster based wireless sensor networks is proposed in this paper. The proposed EEHMAC protocol uses E-TDMA (Energy efficient TDMA) for intra-cluster communication and FDMA (Frequency Division Multiple Access) for inter-cluster communication. IDS (Iterative Deepening Search) based Scheduling algorithm is used for assigning time slot and frequency slot to nodes. Nodes in EEHMAC follow the periodic duty cycle, which reduces the idle listening, and overhearing problems. Simulation results reveal that an average of 18% energy saving is achieved compared to LEACH (Low Energy Adaptive Clustered Hierarchy) protocol and 10% energy is saved in comparison with GH-MAC (Graph theory based Hybrid MAC) protocol. It is evident that delay of EEHMAC is reduced by 17% and throughput is increased by 15% under all traffic conditions. These results demonstrate that EEHMAC performs better than existing MAC protocols in terms of energy efficiency, delay and throughput.展开更多
面对生命这一结构复杂、层级丰富、动态性强的系统,应当如何选择并采用更为有效的方法开展研究?这一问题的答案与重点在生命科学的不同发展阶段也不尽相同。20世纪90年代两则经典故事:《道格的救赎》(The Salvation of Doug)与《比尔的...面对生命这一结构复杂、层级丰富、动态性强的系统,应当如何选择并采用更为有效的方法开展研究?这一问题的答案与重点在生命科学的不同发展阶段也不尽相同。20世纪90年代两则经典故事:《道格的救赎》(The Salvation of Doug)与《比尔的消亡》(The Demise of Bill),曾以汽车为类比对象,用讽刺笔法生动呈现了遗传学家与生物化学家理解汽车运行机制所采用的不同研究策略:是通过拆解组分、解析互作来揭示潜在机制,还是借助功能扰动来识别系统的关键环节?哪种方法能更有效解析生命过程?作为启发式寓言,它们在当时引发了关于不同研究方法优劣与互补性的广泛讨论。时至今日,这两则故事仍是教学中的重要素材。当前,生命科学进入高通量、高精度、多维度融合的新阶段,传统的单一路径研究策略已难以支撑对复杂生命过程深入而系统地理解。生命活动具有模块化结构、调控网络、非线性响应以及适应性补偿等诸多特性,而单一策略往往仅能捕捉其局部、静态特征,难以还原整体的动态特征和调控规律,从而限制了对复杂生命过程的系统认知,也制约了理论深化与应用突破。基于此,本文尝试对上述两个经典故事进行了续写,将其延伸至更具时代特征的场景中,并赋予了主角具有象征意义的中文名字:“知微”(代表生化路径)和“思序”(象征遗传思路)。通过讲述他们在探索智能电动汽车系统的运行原理过程中,如何从各自为营的局面逐渐走向协作与共赢,运用高通量手段,开展系统性分析,并引入数字仿真建模,逐步揭示复杂系统行为背后的结构特性与运行逻辑。故事呼应当前生命科学对系统性与动态性研究的日益重视及其所面临的挑战,强调方法融合与创新的关键作用,鼓励读者思考遗传学方法在当代研究范式中的定位与价值,旨在为遗传学及相关学科的教学提供参考。展开更多
在多小区无线局域网(Wireless Local Area Networks,WLAN)中,由于存在小区间接入访问点同频干扰,以及小区间同频用户干扰,其系统性能与单小区网络具有很大不同。本文提出了支持多种用户传输速率共存、支持用户非均匀分布的多小区WLAN系...在多小区无线局域网(Wireless Local Area Networks,WLAN)中,由于存在小区间接入访问点同频干扰,以及小区间同频用户干扰,其系统性能与单小区网络具有很大不同。本文提出了支持多种用户传输速率共存、支持用户非均匀分布的多小区WLAN系统吞吐率估计算法。通过对多小区WLAN巾接入访问点的布置、信道的配置进行仿真,结果表明即使在存在小区间同频干扰的情况下,估计算法也能得到满意的吞吐率估计结果。展开更多
对SCI/RT(scalable coherent interface for real time)TRAIN协议直接传输模式的分析表明,标准直接传输模式具有延迟小的特点,但其对环路带宽的利用率不高。为增加直接传输模式可用环路带宽,提高环路利用率,提出了基于矩阵判决的直接传...对SCI/RT(scalable coherent interface for real time)TRAIN协议直接传输模式的分析表明,标准直接传输模式具有延迟小的特点,但其对环路带宽的利用率不高。为增加直接传输模式可用环路带宽,提高环路利用率,提出了基于矩阵判决的直接传输新方法。基于OPNET软件建立协议模型,通过不同场景和节点数环路的仿真对比,表明该方法较标准直接传输模式具有更好环路利用率;根据不同的数据包发送模式,直接传输模式可用带宽至少提高约25%;且算法在不同规模和配置的环路中均可使用。展开更多
建立了基于OPNET软件的SCI/RT(Scalable Coherent Interface for RealTime)TRAIN协议仿真模型,对流量均衡问题进行仿真分析.结果显示,当环路负载增加时,每个节点流量的增量是不同的.在环路处于重负载时,远离管理者的节点得到的流量近似...建立了基于OPNET软件的SCI/RT(Scalable Coherent Interface for RealTime)TRAIN协议仿真模型,对流量均衡问题进行仿真分析.结果显示,当环路负载增加时,每个节点流量的增量是不同的.在环路处于重负载时,远离管理者的节点得到的流量近似于零,而靠近管理者的节点基本上占用了所有的环路流量.SCI/RT TRAIN协议提出管理者迁移流量均衡方式解决这个问题.通过对8节点环路进行仿真,得出管理者迁移方法的均衡效果依赖于管理者在环路的配置方式的结论,当每个节点均具有管理者功能时,环路均衡效果达到最好.提出了扩展子优先级的流量均衡新方法.8节点环路的仿真结果显示,该方法具有更好的流量均衡能力和更高的节点流量.同时,通过对扩展子优先级均衡方法在6节点,10节点和12节点环路的仿真,证明了该方法在不同规模的环路中均可使用.展开更多
文摘In this paper, we have used the distributed mean value analysis (DMVA) technique with the help of random observe property (ROP) and palm probabilities to improve the network queuing system throughput. In such networks, where finding the complete communication path from source to destination, especially when these nodes are not in the same region while sending data between two nodes. So, an algorithm is developed for single and multi-server centers which give more interesting and successful results. The network is designed by a closed queuing network model and we will use mean value analysis to determine the network throughput (b) for its different values. For certain chosen values of parameters involved in this model, we found that the maximum network throughput for β≥0.7?remains consistent in a single server case, while in multi-server case for β≥ 0.5?throughput surpass the Marko chain queuing system.
基金performed in the Project “Research on the Hierarchical Interference Elimination Technology for UDN Based on MIMO” supported by the Henan Scientific and Technological Research Project (172102210023)“Research on clustering and frequency band allocation in JT-Co MP supported by Department of Education of Henan Province (19A510013)”
文摘To reduce the interference among small cells of Ultra-Dense Networks(UDN),an improved Clustering-Assisted Resource Allocation(CARA)scheme is proposed in this paper.The proposed scheme is divided into three steps.First,an Interference-Limited Clustering Algorithm(ILCA)based on interference graph corresponding to the interference relationship between Femtocell Base Stations(FBSs),is proposed to group FBSs into disjoint clusters,in which a pre-threshold is set to constrain the sum of interference in each cluster,and a Cluster Head(CH)is selected for each cluster.Then,CH performs a twostage sub-channel allocation within its associated cluster,where the first stage assigns one sub-channel to each user of the cluster and the second stage assigns a second sub-channel to some users.Finally,a power allocation method is designed to maximize throughput for a given clustering and sub-channel configuration.Simulation results indicate that the proposed scheme distributes FBSs into each cluster more evenly,and significantly improves the system throughput compared with the existing schemes in the same scenario.
文摘The efficient use of energy is an important performance metric to extend the lifetime of wireless sensor networks. Since major energy consumption of node is due to its transceiver, the design of MAC protocol plays a vital role in sensor network design. In cluster based sensor networks, due to the different functions of member node and cluster head node, the usage of common MAC protocol results increased energy consumption. To overcome this problem, a novel energy efficient hybrid MAC protocol (EEHMAC) for cluster based wireless sensor networks is proposed in this paper. The proposed EEHMAC protocol uses E-TDMA (Energy efficient TDMA) for intra-cluster communication and FDMA (Frequency Division Multiple Access) for inter-cluster communication. IDS (Iterative Deepening Search) based Scheduling algorithm is used for assigning time slot and frequency slot to nodes. Nodes in EEHMAC follow the periodic duty cycle, which reduces the idle listening, and overhearing problems. Simulation results reveal that an average of 18% energy saving is achieved compared to LEACH (Low Energy Adaptive Clustered Hierarchy) protocol and 10% energy is saved in comparison with GH-MAC (Graph theory based Hybrid MAC) protocol. It is evident that delay of EEHMAC is reduced by 17% and throughput is increased by 15% under all traffic conditions. These results demonstrate that EEHMAC performs better than existing MAC protocols in terms of energy efficiency, delay and throughput.
文摘面对生命这一结构复杂、层级丰富、动态性强的系统,应当如何选择并采用更为有效的方法开展研究?这一问题的答案与重点在生命科学的不同发展阶段也不尽相同。20世纪90年代两则经典故事:《道格的救赎》(The Salvation of Doug)与《比尔的消亡》(The Demise of Bill),曾以汽车为类比对象,用讽刺笔法生动呈现了遗传学家与生物化学家理解汽车运行机制所采用的不同研究策略:是通过拆解组分、解析互作来揭示潜在机制,还是借助功能扰动来识别系统的关键环节?哪种方法能更有效解析生命过程?作为启发式寓言,它们在当时引发了关于不同研究方法优劣与互补性的广泛讨论。时至今日,这两则故事仍是教学中的重要素材。当前,生命科学进入高通量、高精度、多维度融合的新阶段,传统的单一路径研究策略已难以支撑对复杂生命过程深入而系统地理解。生命活动具有模块化结构、调控网络、非线性响应以及适应性补偿等诸多特性,而单一策略往往仅能捕捉其局部、静态特征,难以还原整体的动态特征和调控规律,从而限制了对复杂生命过程的系统认知,也制约了理论深化与应用突破。基于此,本文尝试对上述两个经典故事进行了续写,将其延伸至更具时代特征的场景中,并赋予了主角具有象征意义的中文名字:“知微”(代表生化路径)和“思序”(象征遗传思路)。通过讲述他们在探索智能电动汽车系统的运行原理过程中,如何从各自为营的局面逐渐走向协作与共赢,运用高通量手段,开展系统性分析,并引入数字仿真建模,逐步揭示复杂系统行为背后的结构特性与运行逻辑。故事呼应当前生命科学对系统性与动态性研究的日益重视及其所面临的挑战,强调方法融合与创新的关键作用,鼓励读者思考遗传学方法在当代研究范式中的定位与价值,旨在为遗传学及相关学科的教学提供参考。
文摘在多小区无线局域网(Wireless Local Area Networks,WLAN)中,由于存在小区间接入访问点同频干扰,以及小区间同频用户干扰,其系统性能与单小区网络具有很大不同。本文提出了支持多种用户传输速率共存、支持用户非均匀分布的多小区WLAN系统吞吐率估计算法。通过对多小区WLAN巾接入访问点的布置、信道的配置进行仿真,结果表明即使在存在小区间同频干扰的情况下,估计算法也能得到满意的吞吐率估计结果。
文摘对SCI/RT(scalable coherent interface for real time)TRAIN协议直接传输模式的分析表明,标准直接传输模式具有延迟小的特点,但其对环路带宽的利用率不高。为增加直接传输模式可用环路带宽,提高环路利用率,提出了基于矩阵判决的直接传输新方法。基于OPNET软件建立协议模型,通过不同场景和节点数环路的仿真对比,表明该方法较标准直接传输模式具有更好环路利用率;根据不同的数据包发送模式,直接传输模式可用带宽至少提高约25%;且算法在不同规模和配置的环路中均可使用。
