A Deadlock-free Routing Algorithm for Locally Twisted Cubes

The n-dimensional locally twisted cube(LTQ_(n)) is a newly introduced interconnection network for parallel computing.First, the authors illustrate that there exists deadlock in the minimal routing algorithm.Second,by employing the common virtual network dividing technique,a new routing algorithm is presented,which is proved to be deadlock-free.By exploring the property that one LTQ_(n) consists of one n-1-dimensional hypercube(Q_(n-1)) and one n-1-dimensional 2-twisted cube(Q_(n1,2)),the authors apply the existing adaptive routing strategies for Q_(n-1) and Q_(n-1,2) to induce an adaptive routing scheme for LTQ_(n).So the algorithm can route adaptively in the Q_(n-1)0 or in the Q_(n-1,2)1.     

移动Ad Hoc网络AODV路由协议的研究与优化

无线移动自组网是仅由移动节点所组成的网络,具有分布式控制、自组织、多跳等特点,由于该网络具有抗毁性能高、易铺设等性质,越来越受到业界的广泛关注。原始的路由协议已经满足不了现有网络不可预测、频繁变化的拓扑结构的需要,因此,在之前研究的基础上,对现有Ad Hoc网络AODV路由协议进行了研究,并设计出一种基于AODV协议的改进路由协议——基于认知的AODV协议(Cognitive-based AODV,CAODV)。通过NS2进行试验仿真,结果表明,CAODV协议具有比AODV协议更加优良的性质,可以有效降低重启路由发现频率,增加断裂链路的修复成功率,降低协议的控制负载,对现有网络的动态变化具有很强的适应能力。     

On-demand routing algorithm based on load balancing and mobility prediction in wireless mobile Ad hoc network

The traditional routing protocol for wireless mobile ad hoc networks is unable to achieve balanced energy consumption and could not adapt to the dynamic topology changes well.A novel on-demand rooting algorithm is proposed based on load balancing and mobility prediction.The proposed rooting algorithm excludes the unstable links in routing discovery,and allows the node with more energy forward the routing request packet preferentially.In addition,it adopts the active local routing recovery strategy by predicting the link connection time,and finishes the repair work before the link being actually failure.The simulation experiments demonstrate that,comparing with the traditional AODV protocol,with slight increase of the rooting control overhead,the proposed algorithm increases the average packet delivery ratio,decreases the average end-to-end delay of the data packets,and achieves load balancing in the network and prolong the life-span of the network,which shows the proposed algorithm is highly practical.     

Segmentation algorithm for urinary sediment image combiningwavelet transform and 2D Maximum entropy threshold

In order to solve the problem that urine sediment visible components cannot be segmented effectively because of complex components, complicated defocusing in image and poor discrimination between object and background, a method based on combination algorithm wis designed to segment urine sediment. The wavelet transform wis used to erase the effect of defocusing. Then morphology wis utilized to get the subimages that include the particles. The segmentation method combining the wavelet transform based segmentation and the two dimensional entropy threshold based segmentation wis employed to segment urine sediment visible components. Experimental results show that the proposed method can segment urinary sediment images effectively and precisely.     

An Unicast Fault-tolerant Routing Algorithm on Locally Twisted Cubes

The locally twisted cube is a newly topological structure of network. The authors we design a unicast fault-tolerant routing algorithm on the locally twisted cube by utilizing safety levels and the feature of the network. The performance of the proposed algorithm is evaluated through simulation experiments. When the number of faulty nodes reaches or exceeds half of the total, it can still achieve a quite high percentage of successful routing. An additional advantage of the routing algorithm is that it is highly probable that the selected route be a shortest route between the associated nodes.     

Routing protocol of the wireless sensor networks for bridge health monitoring

By analyzing the reason that why the existing routing protocols cannot be applied to the wireless sensor networks for bridge health monitoring, a new routing protocol is proposed. Since the locations of the collecting modules are fixed, the proposed protocol exchanges the routing information between the neighbor nodes by adjusting the exchange cycle according to reliability of the modules. For the low routing security requirement, while to increase the routing efficient, the middle nodes replying the routing requirements with variable thresholds is introduced. In order to make full use of information in route discovering procedure, the backup routes mechanism is adopted. The proposed protocol can efficiently forward data and is suitable for the bridge health monitoring.     

基于主成分分析的BP神经网络估算藏北高寒草地覆盖度变化

藏北高寒牧区草地是中国高寒草地分布面积最大的地区。为了及时准确地获得该区域草地覆盖度的变化趋势,本研究利用多年气象数据、社会统计数据、GIMMS、MODIS两种归一化植被指数（NDVI）数据作为参数,构建 BP神经网络模型,估算2010—2014年藏北高寒草地年际变化趋势,并用主成分分析方法优化参数来改进模型。结果表明,① BP神经网络模型及其改进模型对藏北高寒草地覆盖度年际变化趋势与遥感值的相关系数为0.16、0.47,表明通过主成分分析优化参数后的BP神经网络模型具有较好的模拟效果。 ②两种BP神经网络估算的植被指数值与NDVI值平均误差率分别为2.36%、2.20%。均有较高的模拟精度。③从神经网络训练步数上看,BP神经网络结果训练收敛步长为5000,基于主成分分析的BP神经网络模型训练收敛步长为454,表明后者提高了计算效率,体现出良好的收敛性。因此,无论从年际变化趋势拟合程度、植被指数估算值精度、还是从计算效率来看,改进的BP神经网络模型对于估算藏北高寒草地覆盖度变化更加行之有效。     

An Adaptive Data Burst Assembly Algorithm in OBS Networks

Optical Burst Switching (OBS) is a promising paradigm for the next-generation Internet infrastructure. This paper proposes an adaptive dada burst assembly algorithm in OBS networks, which can adjust parameters of assembly algorithm according to the traffic arrival rate of the edge nodes in OBS networks. Also this paper proposes how to realize the adaptive data burst assembly algorithm.     

Optimal sensor deployment scheme for heterogeneous wireless sensor networks

For the high density of distributed heterogeneity nodes in wireless sensor networks (WSNs), the optimal sensor deployment is studied. A cost optimal heterogeneous sensor deployment scheme based on genetic algorithm is proposed. The cost of sensor node deployment is used as objective function for optimization computation subjected to network coverage and fault tolerance to obtain the suitable types and positions of the sensors. The algorithm can be used for boolean sensing model as well as probabilistic sensing model. The simulation results demonstrate that the proposed algorithm converges fast toward the optimal solutions and reduces the cost of sensor deployment, which is feasible for heterogenous nodes deployment in WSNs.     

A multi-parameter weighted clustering algorithm for mobile ad hoc networks

Network clustering can support resource spatial multiplexing and increase the capacity of the wirless networks. Clusterheads constitute the virtual backbone of the network, which reduces the overhead of routing and makes it simpler and easier for network     

Reliability Evaluation of Middle Voltage Distribution Networks

A reliability evaluation algorithm for middle voltage radial distribution network is presented. The algorithm applied ahead-searching-method to determining the area of breaker influencing, applied bidirectional-searching-method to determining faulting area, and applied behind-searching-method to determining connection switch. Then the type of nodes is determined. The reliability index of nodes,feerders and system can be easily computed by the type of nodes.So the computing effeciency is improved. At the same time, the curtailing load algorithms for low-voltage of buses and over-capacity of lines are presented and the foundation for the reliability assessment is established considering the power flow restriction. From the RBTS68-bus and other middle radial distribution networks,the effectiveness and availability of the method are verified.     

Restoration algorithm with wavelength reservation collision avoidance in ASON

Aiming at the problem of link fault restoration in ASON, an improved equalizing routing algorithm (ERA) is introduced to proportion the load at the routing phase. In order to solve the easy blocking problem for the network without wavelength converter because of the wavelength continuity constraint, the algorithm WRCA is proposed at the wavelength assignment phase. This algorithm is realized by adding collision detection object (CDO) in the path message of the resource reservation protocol with traffic engineering extension (RSVP TE). Depending on the value of the CD flag, different wavelength selection strategies are applied at the destination node, and the blocks resulting from wavelength reservation collision are reduced. The simulation experiments compare four wavelength assignment algorithms with the same routing algorithm ERA. The results show that compared with the traditional first fit algorithm (FF) and random fit algorithm (RD), the FF and RD employing CD scheme can effectively reduce the blocking ratio of the whole network, and enhance the practical applicability of the restoration algorithms.     

Fault-tolerant Wormhole Routing Algorithm for Honeycomb Networks

Honeycomb meshes are topological structures for connecting processors within parallel computers. The unicast routing strategy on honeycomb meshes are studied. It is indicated that a previous known routing algorithm may suffer from deadlock. A deadlock-free routing algorithm known as the XYZ-ROUTE algorithm is presented by employing the classical virtual channel technique. This algorithm is improved to make it work properly in the presence of convex faults.     

Computer Aided Decision-Making System of Power System Reliability Evaluation Based on Object-oriented

The reliability is an important component part of research fields in power system. This paper presents an application of object oriented programming to develop reliability evaluation system of electric networks. A new approach to reliability evaluation and graph expression is proposed, and a computer aided decision making system of electric network reliability evaluation using Visual C++ 5.0 under Windows95 environment is developed. The system can provide reliability data for power system operation and plan, which is the foundation for operation and decision making. It has the characteristics of better expansibility, convenient usage, user friendly interfaces and so on.     

A fuzzy logic multicasting algorithm for ad hoc networks

To increase the multicasting efficiency of Ad hoc networks, a fuzzy logic multicasting algorithm (FLMA) is proposed. FLMA adopts the fuzzy logic to tolerate the imprecise information caused by dynamic network topology. The two input variables of the fuzzy logic system are the relative degree of the additional coverage node number and the relative degree of the residual energy. The deferring time of rebroadcast is the output variable of the fuzzy logic system, which is used to optimize the priority of the nodes to rebroadcast. FLMA reduces the redundant retransmission and the chance of the contention and collision, while balances the energy consumption of the nodes. Simulation results reveal that the FLMA achieves better performance than BCAST in terms of the network lifetime, average end-to-end delay, the average number of drops per node and the throughput.     

The optimal energy efficiency of wireless networks nodes based on solar cells

To improve the energy efficiency of solar cells in wireless sensor networks nodes, the energy relationship between solar cells and the wireless sensor networks nodes is studied. An adaptive algorithm is adopted to ensure the wireless sensor networks work normally at different sunlight intensities. An energy model is designed that reveals the energy relationship between the output power of the solar cells and the power of nodes working normally at a standard sunlight intensity. The experimental results show that the model represents the adaptive energy relationship between the solar cells and the nodes, ensures that the nodes work stably in a long term, and extends the life cycle of the sensor networks as long as possible. The model has important guiding significance for wireless sensor networks designation.     

An Algorithm to Enhance the Performance of Data Service Over CATV Broadband Networks

Emerging CATV networks are evolution to Hybrid Fiber/Coax plants. It is widely believed that the HFC network will play an important role in providing broadband accessing service to subscribers due to it's large excess bandwidth and high penetration to the home. Asymmetry broadband data service is the main service provided in the HFC broadband access networks now. It's performance will determine whether the subscribers be satisfied or not and affect the growth of HFC broadband access networks. The authors outline the mechanism of transmitting data in the upstream channel of the HFC network, and analyze how it affecting the performance of data service. The performance of data service and TCP protocol in HFC network is examined. An optimal scheme of bandwidth allocating algorithm for the upstream channel is proposed to enhance the performance of the data service over these networks.     

Constitutive model for soils based on the concept of disturbing structure

Based on the concept of disturbing structure, this paper presents a progressive yield constitutive model by extending the Cam Clay model in order to describe influence of the disturbing structure on soil behavior. The internal variable of yield surface is not just a constant parameter, and it should be treated as a distribution function in a range. The single yield surface of the Cam Clay model wis extended to a field of yield surface. Then by introducing the progressive yield concept into the Cam Clay model, the progressive yield constitutive model wis developed. Only one parameter wis added besides the three parameters of the Cam Clay, which represents the disturbing structure of the soils. The application results show that the model can predict the progressive yield of the soils.     

An improved HEED clustering algorithm for Wireless Sensor Network

In wireless sensor network, routing protocols which based on clustering have the advantages of energy consumption, topology management and data fusion. The HEED protocol, which generates cluster heads based on distributed algorithm, drives up the rate of clustering and creates well distributed cluster heads. However, it does not consider the mobility of nodes in the network. When the distance between neighbor nodes has changed, the AMRP method which decides the node belongs to different cluster heads would cause problems such as high energy consumption, short lifetime of network and so on. Responding to these problems, the paper proposes the S HEED, a clustering algorithm based on stability, which chooses the stability as a parameter of nodes when choosing a cluster head. With S HEED algorithm, the high energy consumption problem among cluster nodes and cluster heads caused by the mobility is tackled. The simulation experiment demonstrates that the S HEED algorithm lower the energy consumption of cluster heads and prolongs the network lifetime.     

Clustering Routing for Wireless Sensor Networks

In wireless sensor networks that consist of a large number of low-power sensors.Because the sensor's energy is limited,one of the main design is to obtain long system lifetime.The authors firstly analyse LEACH and LEACH-C clustering routing for wireless sensor networks.Aimming at their shortcoming,they present a new routing LEACH-NEW.This routing uses multi ho Pinstead of one hop.At last,they use NS2 to simulate them.Simulation show results that new routing exhibits noticeably longer system lifetime than rouing LEACH and LEACH-C.