无结网编织工艺研究

针对当前无结网成网技术中存在织物质量较差和内部纤维强度损失较大的问题,研究了一种新型无结网状织物的编织工艺。通过结合编织技术原理与无结网结构特征,分析了无结网成型原理,并以四纱网脚作为研究对象,对其网脚及网结的编织轨道形式进行了设计,进而探讨纱锭无干涉分布规律。在此基础上对纱锭无干涉分布规律进行拓展,分析了采用4个多槽口叶轮编织多纱无结网的纱锭分布规律。依据纱锭在轨道盘上的无干涉分布规律获得可行分布方案,针对某个分布方案进行无结网实物编织实验,验证了所研究无结网工艺的合理性,并确认无结网的编织工艺需综合考虑纱锭运动轨道、纱锭分布及叶轮规格的影响。

基于流固耦合的尼龙网流场特性及变形分析

考虑到柔性网衣在水流作用下易发生变形,会造成网箱有效体积减小并伴随网衣撕裂风险,因此研究网衣周围流场变化及网衣变形特性具有重要意义。基于剪应力SST k-ω湍流模型,结合ANSYS Workbench的单向流固耦合(Fluid-Solid Interaction,FSI)方法,将网衣所受压力作为输入载荷施加在平面网表面,研究在不同流速、网衣密实度和攻角情况下平面尼龙无结网衣的流场特性,对大变形非线性网衣结构的有限元模型进行分析。结果表明基于FSI的单向耦合数值模拟用于平面网衣变形及流场特性分析具有可行性,网衣造成的流速降低现象在不同攻角条件下的差异较明显。得到网衣水动力系数在不同流速、网衣密实度和攻角下的变化情况,以及平面网的等效应力分布特点和变形随攻角变化的特性,发现从网衣中心网线至边缘位置网线处的应力由大逐渐变小,最终在网线固定端附近发现应力最大位置。

小尺度平面网衣流场特性数值研究

恶劣海洋条件给网箱养殖带来许多潜在风险,研究金属网衣的水动力特性及其周围的流场特性关系着鱼群养殖的质量和网箱安全性。本文基于计算流体力学(CFD)方法对小尺度平面无结金属网衣进行了数值模拟实验,研究其在均匀流作用下的水动力性能和网衣周围的流场分布,得出了随着雷诺数、网衣的攻角、网衣密实度和网眼形状变化阻力系数的变化趋势和速度场的分布变化。这些分析结果对进一步研究网衣的水动力性能和流场特性具有借鉴意义。

网箱养鳖

网箱养鳖是利用较大的池塘、水库、湖泊的湾汉和水流较缓的河道等来养鳖。网箱养鳖,成活率高,质量好,成本低,是养鳖的一条新路子。

An efficient reliability evaluation method for industrial wireless sensor networks

Aimed at the difficulties in accurately, comprehensively and systematically evaluating the reliability of industrial wireless sensor networks （WSNs）, a time-evolving state transition-Monte Carlo （TEST-MC） evaluation method and a novel network function value representation method are proposed to evaluate the reliability of the IWSNs. First, the adjacency matrix method is used to characterize three typical topologies of WSNs including the mesh network, tree network and ribbon network. Secondly, the network function value method is used to evaluate the network connectivity, and the TEST-MC evaluation method is used to evaluate network reliability and availability. Finally, the variations in the reliability, connectivity and availability of these three topologies are presented. Simulation results show that the proposed method can quickly analyze the reliability of the networks containing typical WSN topologies, which provides an effective method for the comprehensive and accurate evaluation of the reliability of WSNs.

网箱暂养河蟹技术

河蟹秋季捕获后不能马上运销时,需要进行暂养,除用水泥池等其它设施外,利用网箱暂养河蟹是一项行之有效的措施。辽宁省盐碱地利用研究所1988年9月至12月,利用网箱暂养河蟹,取得了较好效果。其主要经验是: 1、采用聚乙稀无结网片制做的装蟹网箱,制做工艺与鱼箱基本一样,但容积较小的网箱暂养河蟹的效果较好。可制成长2—3米,宽1～2米,高0.3～0.5米长方形封闭式网箱,在上方箱角处安装一条长1米双拉锁(单的也可以)塑料拉链做为箱口,方便作业。箱的底部四周边角,加缝一条宽0.2米左右小目网片。

The Study of Farmland Information Management System based on Wireless Sensor Networks

To satisfy the need of good quality and high yield primary production,the farmland information management system based on wireless Sensor Network has been proposed.We give priority to analyzing the basic function of the system,building the systematic structure of applied system and network system,and implementing the energy control and safety design of system.The system can reduce manpower operation and the error of manual measuration in the course of practical production,reduce the cost of agricultural production,and realize automatization of agricultural production to the largest extent to provide an effective way to realize good quality and high yield primary production,which has an important realistic meaning.

Generation of scale-free knowledge network with local world mechanism

In order to simulate the real growing process, a new type of knowledge network growth mechanism based on local world connectivity is constructed. By the mean-field method, theoretical prediction of the degree distribution of the knowledge network is given, which is verified by Matlab simulations. When the new added node＇s local world size is very small, the degree distribution of the knowledge network approximately has the property of scale-free. When the new added node＇s local world size is not very small, the degree distribution transforms from pure power-law to the power-law with an exponential tailing. And the scale-free index increases as the number of new added edges decreases and the tunable parameters increase. Finally, comparisons of some knowledge indices in knowledge networks generated by the local world mechanism and the global mechanism are given. In the long run, compared with the global mechanism, the local world mechanism leads the average knowledge levels to slower growth and brings homogenous phenomena.

为什么推广网箱养鱼进展不大?

网箱养鱼是一项引进的技术,亩产鲜鱼可达一、二万斤以上,比起池塘养鱼要高出九倍,甚至几十倍。上海市水产研究所于1975年进行试验,取得了一定成效。但历年来在上海推广,总是进展不大。查其原因,就是网箱成本太高。按上海绳网厂出品的网箱成本计算,

泥鳅水泥池低碳生物膜养殖试验

近年来,由于养殖水体环境的污染,生物膜逐渐被我们所认识,在水产养殖上的运用也越来越广泛。它对于降解养殖水体溶解无机氮、截留水体悬浮物、维持养殖水体的正常循环利用起到重要作用。

海参池塘网箱养殖勃氏雅罗鱼技术研究

勃氏雅罗鱼Leuciscus brandti（Dybowski）又称为大红线、金滩头、银滩头,它是唯一在海水中生长,到淡水中产卵的洄游性鲤科鱼类,有着广阔的市场前景。东营市地处黄河三角洲,有着大面积的海参养殖池塘,海参具有夏眠的习性,这段时间对于勃氏雅罗鱼的生长则极为有利。为此我们开展了该鱼在海参池塘的网箱养殖试验,现将试验情况总结如下：1材料1.1池塘条件池塘面积1.3hm2（20亩）,坡比1∶2.5,

池塘刺参苗种网箱与网笼不同模式暂养试验

由辽宁省水产技术推广总站主持的中央财政《刺参优质健康苗种生态繁育技术示范推广》项目于2014-2015年在我地区实施。在项目实施的过程中我们进行了“刺参网箱与网笼不同模式的暂样试验”。

Optimized Multicast Routing Algorithm Based on Tree Structure in MANETs

Mobile Ad hoc Networks(MANETs) play an important role in emergency communications where network needs to be constructed temporarily and quickly.Since the nodes move randomly,routing protocols must be highly effective and reliable to guarantee successful packet delivery.Based on the data delivery structure,most of the existing multicast routing protocols can be classified into two folders:tree-based and mesh-based.We observe that tree-based ones have high forwarding efficiency and low consumptions of bandwidth,and they may have poor robustness because only one link exists between two nodes.As a treebased multicast routing protocol,MAODV(Multicast Ad hoc On-demand Vector) shows an excellent performance in lightweight ad hoc networks.As the load of network increases,QoS(Quality of Service) is degraded obviously.In this paper,we analyze the impact of network load on MAODV protocol,and propose an optimized protocol MAODV-BB(Multicast Ad hoc On-demand Vector with Backup Branches),which improves robustness of the MAODV protocol by combining advantages of the tree structure and the mesh structure.It not only can update shorter tree branches but also construct a multicast tree with backup branches.Mathematical analysis and simulation results both demonstrate that the MAODV-BB protocol improves the network performance over conventional MAODV in heavy load ad hoc networks.

Analysis of distribution uniformity of nodes in wireless sensor networks

Wireless sensor networks have several special characteristics which make against the network coverage, such as shortage of energy, difficulty with energy supply and so on. In order to prolong the lifetime of wireless sensor networks, it is necessary to balance the whole network load. As the energy consumption is related to the situation of nodes, the distribution uniformity must be considered. In this paper, a new model is proposed to evaluate the nodes distribution uniformity by considering some parameters which include compression discrepancy, sparseness discrepancy, self discrepancy, maximum cavity radius and minimum cavity radius. The simulation results show that the presented model could be helpful for measuring the distribution uniformity of nodes scattered randomly in wireless sensor networks.

A Frameless Network Architecture for the Way Forward of C-RAN

The key technologies involved in the evolution of the Cloud-based Radio Access Network(C-RAN) are discussed in this paper. Taking the Frameless Network Architecture(FNA) as a starting point, a cell-lessbased network topology for a multi-tier Heterogeneous Network(Het Net) and ultra-dense network is proposed. The FNA network topology modeling is researched with centralized processing and distributed antenna deployments. The Antenna Element(AE) is released as a new dimensional radio resource that is included in the centralized Radio Resource Management(RRM) processes. This contributes to the on-demand user-centric serving-set associations with cell-edge effect elimination. The Control Plane(CP) and User Plane(UP) separation and adaptation are introduced for energy efficiency improvements. The centralized RRM and different optimization goals are discussed for fully exploring the merits from the centralized computing of C-RAN. Considering the complexity, near-optimal approaches for specific users' Quality-of-Service(Qo S) requirements are addressed. Finally, based on the research highlighted above, the way forward of C-RAN evolution is discussed.

Design and validation of wireless acceleration sensor network for structural health monitoring

A wireless sensor network is proposed to monitor the acceleration of structures for the purpose of structural health monitoring of civil engineering structures. Using commercially available parts, several modules are constructed and integrated into complete wireless sensors and base stations. The communication protocol is designed and the fusion arithmetic of the temperature and acceleration is embedded in the wireless sensor node so that the measured acceleration values are more accurate. Measures are adopted to finish energy optimization, which is an important issue for a wireless sensor network. The test is perfonned on an offshore platform model, and the experimental results are given to show the feasibility of the designed wireless sensor network .

Compressed SNR-and-Channel Estimation for Beam Tracking in 60-GHz WLAN

Signal-to-noise ratio （SNR） and channel estimations are critical for 60-GHz communications to track the optimal trans- mission and reception beam pairs. However, the excessive pilot overhead for the estima- tions severely reduces system throughput in fast-rotation scenarios. In order to address this problem, we firstly demonstrate the potential sparseness property of 60-GHz channel in beam tracking; subsequently, via exploiting this property, we propose a novel compressed SNR-and-channel estimation. The estimation is conducted in a three-stage fashion, includ- ing the unstructured estimation, nonzero-tap detection, and structured estimation with non- zero-tap location. Numerical simulations show that, in the case of substantial reduction of the pilot overhead, the proposed estimator still reveals a significant improvement in terms of estimation performance over the scheme in IEEE 802.1 lad. Furthermore, it is also demon- strated that the proposed SNR and channel estimators can approach the lower bounds in sparse channels so long as SNR exceeds 8 dB.

Multilevel Pattern Mining Architecture for Automatic Network Monitoring in Heterogeneous Wireless Communication Networks

The rapid development of network technology and its evolution toward heterogeneous networks has increased the demand to support automatic monitoring and the management of heterogeneous wireless communication networks.This paper presents a multilevel pattern mining architecture to support automatic network management by discovering interesting patterns from telecom network monitoring data.This architecture leverages and combines existing frequent itemset discovery over data streams,association rule deduction,frequent sequential pattern mining,and frequent temporal pattern mining techniques while also making use of distributed processing platforms to achieve high-volume throughput.

Average Range and Network Synchronizability

The influence of structural properties of a network on the network synchronizability is studied by introducing a new concept of average range of edges. For both small-world and scale-free networks, the effect of average range on the synchronizability of networks with bounded or unbounded synchronization regions is illustrated through numerical simulations. The relations between average range, range distribution, average distance, and maximum betweenness are also explored, revealing the effects of these factors on the network synchronizability of the small-world and scale-free networks, respectively.

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.