Cooperative Subcarrier Sensing Using Antenna Diversity Based Weighted Virtual Sub Clustering

The idea of cooperation and the clustering amongst cognitive radios(CRs) has recently been focus of attention of research community, owing to its potential to improve performance of spectrum sensing(SS) schemes. This focus has led to the paradigm of cluster based cooperative spectrum sensing(CBCSS). In perspective of high date rate 4th generation wireless systems, which are characterized by orthogonal frequency division multiplexing(OFDM) and spatial diversity, there is a need to devise effective SS strategies. A novel CBCSS scheme is proposed for OFDM subcarrier detection in order to enable the non-contiguous OFDM(NC-OFDM) at the physical layer of CRs for efficient utilization of spectrum holes. Proposed scheme is based on the energy detection in MIMO CR network, using equal gain combiner as diversity combining technique, hard combining(AND, OR and Majority) rule as data fusion technique and antenna diversity based weighted clustering as virtual sub clustering algorithm. Results of proposed CBCSS are compared with conventional CBCSS scheme for AND, OR and Majority data fusion rules. Moreover the effects of antenna diversity, cooperation and cooperating clusters are also discussed.

Hypergraph High-Dimension Clustering Algorithm for Optimized Cooperative Wireless Multicast

In order to guarantee the wireless multicast throughput at a minimum cost, we propose a layered hypergraph high-dimension clustering algorithm (LayerHC) considering the channels and statistical locations of mobile members. The algorithm can achieve a minimum multicast spanning tree to obtain a minimum number of relays and effective cooperative areas with low computational complexity.

A Cluster-Based Virtual Cooperative MIMO Transmission Scheme

The most essential issue is to ensure the reliability of data transmission during wireless communication and reduce energy consumption of the network for supervising the environmental state using wireless sensor network(WSN).Here,a cluster-based virtual cooperative MIMO transmission scheme(CVCM) is suggested,The proposed scheme involves optimization of cooperative nodes and the modulation speed dynamically as per the distance space the cluster head and the sink node,in order to minimize the communication energy consumption of each virtual MIMO unit and the convergence node,thereby reducing the capacity consumption of the entire network.Simulation and experimental results demonstrate the effectiveness of CVCM in reducing network energy consumption,increasing the network lifetime and improving data reception performance of the base station.

PSO Clustering Algorithm Based on Cooperative Evolution

Among the bio-inspired techniques,PSO-based clustering algorithms have received special attention. An improved method named Particle Swarm Optimization (PSO) clustering algorithm based on cooperative evolution with multi-populations was presented. It adopts cooperative evolutionary strategy with multi-populations to change the mode of traditional searching optimum solutions. It searches the local optimum and updates the whole best position (gBest) and local best position (pBest) ceaselessly. The gBest will be passed in all sub-populations. When the gBest meets the precision,the evolution will terminate. The whole clustering process is divided into two stages. The first stage uses the cooperative evolutionary PSO algorithm to search the initial clustering centers. The second stage uses the K-means algorithm. The experiment results demonstrate that this method can extract the correct number of clusters with good clustering quality compared with the results obtained from other clustering algorithms.

Evolutionary prisoner's dilemma game on highly clustered community networks

This paper studies the evolutionary prisoner＇s dilemma game on a highly clustered community network in which the clustering coefficient and the community size can be tuned. It finds that the clustering coefficient in such a degree-homogeneous network inhibits the emergence of cooperation for the entire range of the payoff parameter. Moreover, it finds that the community size can also have a marked influence on the evolution of cooperation, with a larger community size leading to not only a lower cooperation level but also a smaller threshold of the payoff parameter above which cooperators become extinct.

Theoretical Studies on the Stabilities and Hydrogen Bond Actions of (H_2O)_n Clusters

The stable configurations and hydrogen bond nature of （H2O）n clusters （n = 3-6） have been investigated by the B3LYP method at the 6-31＋＋g^＊＊ level. Upon calculation, four conclusions have been drawn： （1） In the （H2O）3-5 clusters, cyclic configurations were confirmed to be the most stable. But in the （H2O）3-4 ones, only cyclic configurations could be observed. From n = 5 （（H2O）5 clusters）, three-dimensional configuration could be found： （2） In the （H2O）6 clusters, all configurations are inclined to be three-dimensional except the most stable configuration which is cyclic; （3） The stable order of （H2O）6 clusters indicates that it is the arrangement of hydrogen bond that plays a decisive role in the cluster stabilities, the zero-point energy is also important, and cluster stabilities are independent on the number of hydrogen bonds; （4） There exist strong cooperativity and superadditivity in the （H2O）n clusters.

Coordination game model of co-opetition relationship on cluster supply chains

The research of cluster supply chains is a new direction and a hotspot of the industrial cluster theory. On the condition of the coordination game, the enterprises may be stuck on the non-efficient equilibrium status, which becomes an important problem that must be considered on cluster supply chains. A symmetrical coordination game model is constituted to describe the competition and cooperation relationship of the same-quality manufacturers on cluster supply chains. The methods of the non-cooperation game theory and the evolutionary game theory are respectively used to analyze the model, whose parameters＇ influences under each method are then compared. It can be concluded that the analysis of the evolutionary game theory is more realistic and practical. Finally, three approaches are considered to break away from being path-dependence locked-in non-efficient status during this coordination game evolutionary process, which provide the development of cluster supply chains with an effective forecasting and Pareto optimizing method.

The Coalition Cooperative Game Method and Its Application in Multi-objective Optimization Design

This paper proposes a multi-objective optimization design method based on the coalition cooperative game theory where the three design goals have been seen as three game players. By calculating the affecting factors and fuzzy clustering, the design variables are divided into different strategic spaces which belong to each player, then it constructs a payoff function based on the coalition mechanism. Each game player takes its own revenue function as a target and obtains the best strategy versus other players. The best strategies of all players consist of the strategy permutation of a round game and it obtains the final game solutions through multi-round games according to the convergence criterion. A multi-objective optimization example of the luff mechanism of compensative sheave block shows the effectiveness of the coalition cooperative game method.

Research and implementation of cooperative cache for PVFS

At present, there are many effective ways to achieve high performance in cluster system storage management, including server-end disk, server-end caching, local caching and cooperative caching. The cooperative caching mechanism shares caches among different clients so as to avoid expensive disk access costs and to improve overall throughput of cluster system. In this paper, a Single Copy Cooperative Cache model is proposed together with block lookup algorithm, block replacement algorithm and the consistency algorithm based on the model. Meanwhile, the prototype system of the model is implemented in PVFS file system. Finally, the performance of this system is tested in InfiniBand Framework, the result of which shows that in contrast to the original PVFS system, read performance of PVFS file system is improved by about two times, while write performance is reduced by nearly ten percent.

Fuzzy Service Aware Adaptive Cooperative Spectrum Sensing Algorithm

Based on the service characteristics and the sensing ability for secondary users, a joint optimization scheme of spectrum detection and allocation is investigated to expand the available sensing region and allocate the Qo S-specified channels. On the aspect of spectrum detection, due to the available detection index with the global detection metrics, cooperation thresholds are adaptively adjusted to select the cooperative model for maximizing the available sensing region. On the aspect of spectrum allocation, for different service category, the idle channels are efficiently allocated that depend on their stability and available bandwidth. Meanwhile, based on the requested rates defined by fuzzy theory, the secondary users can be divided into two categories, i.e.,delay sensitive service and reliability sensitive service. Finally, the Qo S-specified channels from the targeted spectrum subset are allocated to secondary users. Simulation results show that our proposed algorithm can not only expand the available sensing region,but also decrease the outage probability of delay sensitive services. Additionally, it enables stable power consumption in the time-variation channel.

Clustering Approaches for Overhead Reduction over Coordinated Multiple Points Network-MIMO Downlink Systems

Owing to the potential for intercell cochannel interference mitigation and significant spectral efficiency improvement, coordinating transmission techniques by multiple radio access points have recently attracted a lot of attention. In this paper, the system structure and mathematical signal model based on clustered structure are presented for multipoint coordinating downlink transmission, the clustered supercell configurations with static/dynamic approaches are discussed, and then optimal precod- ing design is provided for an accepted level of scheduling complexity and reduced signaling over- head. Some simulation results are given to evaluate the performance of different cell-clustering approaches, and to show that a clustered supercell size of 7 is a reasonable choice for clustered coordination with the given transmit power and the reduced feedback.

Operation Mechanism of Farmers' Professional Cooperatives from the Point of Low-Carbon Agricultural Products

We firstly take a look at internal logic of cluster development of low-carbon agricultural products.In combination with operation features of farmers' professional cooperatives and actual requirements for cluster development of low-carbon agricultural products;we elaborate establishing benefit allocation mechanism,bearing education and training functions,forming low-carbon value,building low-carbon identification system,as well as realizing low-carbon value.According to these situations,we systematically analyze operation mechanism of farmers' professional cooperatives suitable for cluster development of low-carbon agricultural products.To promote cluster development of low-carbon agricultural products,we put forward following suggestions,including government guidance and encouragement,social acceptance and active cooperation,and integration into global low-carbon development system to share benefit of low-carbon development.

Optimal Energy Efficiency Resource Allocation Strategy for Cognitive Clustering Network under PUEA Attack

5G has pushed the use of radio spectrum to a new level,and cognitive clustering network can effectively improve the utilization of radio spectrum,which is a feasible way to solve the growing demand for wireless communications.However,cognitive clustering network is vulnerable to PUEA attack,which will lead to the degradation of system detection performance,thereby reducing the energy efficiency.Aiming at these problems,this paper investigates the optimal energy efficiency resource allocation scheme for cognitive clustering network under PUEA attack.A cooperative user selection algorithm based on selection factor is proposed to effectively resist PUEA user attack and improve detection performance.We construct the energy efficiency optimization problem under multi-constraint conditions and transform the nonlinear programming problem into parametric programming problem,which is solved by Lagrangian function and Karush-Kuhn-Tucker condition.Then the sub-gradient iterative algorithm based on optimal energy efficiency under PUEA attack is proposed and its complexity is analyzed.Simulation results indicate that proposed method is effective when subjected to PUEA attacks,and the impact of different parameters on energy efficiency is analyzed.

The Mechanism of Synergetic Innovation on Industrial Clusters

The paper summarizes domestic and overseas research results on synergetic innovation. Then it discusses the mechanism of synergetic innovation on industrial clusters according to these theoretical results. Firstly, we analyze the behavior of synergetic innovation on industrial clusters from a microeconomic point of view. Secondly, we explain component elements of synergetic innovative system. Lastly, we discuss the formative process of synergetic innovation in detail. Thus we can provide synergetic innovation of cluster companies with theoretical guidelines.

A Robust Cooperative Spectrum Sensing Scheme in Cognitive Radio Systems

Performance of cluster-based cooperative spectrum sensing is more greatly improved than that of the traditional cooperative spectrum sensing. However, the style of clusters is not pointed out on traditional cluster-based method. In view of all the fading in the cooperative spectrum sensing, space diversity, and selective diversity, a robust cooperative spectrum sensing scheme based on clusters is proposed. Simulation results show that the detection performance of this new scheme is more close to that of the ideal cluster-based cooperative spectrum sensing scheme, and the excellent performance with higher reliability is gained relative to the actual cluster-based cooperative spectrum sensing scheme. Finally, the number of users in a cluster of the proposed scheme is discussed. The two users in a cluster are not the optimal solution to the overall implementation of cognitive radio.

基于Multi-Agent的无人机集群体系自主作战系统设计

针对无人集群自主作战体系设计中的关键问题,提出基于Multi-Agent的无人集群自主作战系统设计方法。建立无人集群各节点的Agent模型及其推演规则;对于仿真系统模块化和通用化的需求,设计系统互操作式接口和无人集群自主作战的交互关系;开展无人集群系统仿真推演验证。仿真结果表明,所提设计方案不仅能够有效开展并完成自主作战网络生成-集群演化-效能评估的全过程动态演示验证,而且能够通过重复随机试验进一步评估无人集群的协同作战效能,最后总结了集群协同作战的策略和经验。

基于喷泉码信息差异分簇的V2V协作数据分发方案

新兴车联网应用需要分发的数据量不断增加,车辆难以在一个RSU通信范围内收到完整数据,跨RSU通信完成率低,时效性差。针对此问题,提出一种基于喷泉码信息差异分簇的V2V协作数据分发方案。经过喷泉编码的数据由RSU广播;车辆通过XGBoots预测车速,以此计算V2V链路生存时间;链路可靠性和车辆的喷泉码信息差异构建引力模型来分簇,在簇内以V2V传输共享编码包,在保证完成率的前提下大幅降低数据分发延迟。仿真结果表明,与已有方案ECDS相比,对于不同大小的数据,该方案在保证完成率的基础上,平均时延降低了38%。

产业集群视角下校企合作有限理性困境与契约治理探析

职业院校与企业开展合作应签订书面契约。由于有限理性,职业院校与企业在合作过程中不能预测所有可能发生的意外事件,职业教育校企合作面临契约治理困境。在产业集群环境下同行业企业数量多、地理邻近,职业院校与企业之间沟通与交往比较频繁,能增强双方互信,获得丰富的合作经验,从而缓解了有限理性难题。建议针对地区产业发展情况完善职业教育法规条例,分行业制订校企合作契约范本,总结与推广集群区域的校企合作经验,从而提升校企合作契约治理水平,推动校企合作、产教融合高质量发展。

生态耦合下高技术产业集群横向创新链主体合作策略演化

从知识生态耦合视角对集群横向创新链主体合作策略演化展开研究,构建集群横向创新链主体和其邻居合作交互的演化博弈模型,进行系统稳定性分析,并考虑到网络嵌入性,对不同网络规模下的集群横向创新链主体合作策略进行动态演化仿真分析。研究发现,知识互补度能促进集群横向创新链主体间合作策略演化,并且该促进作用存在一个临界值,随着网络规模的增大临界值从0.5上升至0.8,但是网络规模越大网络演化的速度越慢。另外,知识重叠度对集群横向创新链主体间合作策略演化起抑制作用,不过存在一个较低的临界值0.4,当知识重叠度低于临界值时能够促进集群横向创新链主体合作;超过临界值后随知识重叠度的增加,对集群横向创新链主体合作的抑制作用增大,而且知识重叠度产生的作用不受网络规模的影响。

基于网络演化视角的长三角集成电路产业合作创新绩效及影响因素研究

长三角是中国集成电路产业的主要集聚区,但针对该区域集成电路行业产学研多主体深度融合创新绩效的研究较为缺乏。为此,选取1995—2021年长三角集成电路产业的专利数据构建产业合作创新网络,采用ArcGIS可视化手段,通过拓扑结构分析、空间结构分析等方法梳理该网络演化的趋势特征,并基于2021年其中124家集成电路上市企业数据构建结构方程模型,分析长三角集成电路产业合作创新绩效的影响因素。结果表明:长三角集成电路产业合作创新网络的发展可划分为4个阶段,近年来形成了“核心-边缘”的创新网络,网络结构从松散逐渐紧密,网络内区域间联系逐步增强,与区域外主体空间合作的广度和深度不断扩大;企业在合作专利申请行为中的位置优势及经验优势不会影响企业的合作意愿;知识邻近性对关系邻近性和创新绩效的正向影响显著,通过创新绩效对合作创新成果产生中介效应,而且创新绩效对合作创新成果的正向影响显著;环境邻近性显著正向影响知识邻近性且显著负向影响创新绩效。因此,要进一步打造品牌化、国际化和数字化的长三角集成电路产业合作创新公共服务平台,提升长三角集成电路产业合作创新网络的能级。