The compensation method for the random time-delay of the feedbackchannel and the forward channel in the networked control system

An improved predictive control method is presented to compensate the random time delay in the networked control system. The feedback time delay is compensated by predictive controller based on softened increment input strategy. The forward time delay is unknown for controller, so an extra feedback loop is added to compensate the delay by estimating the error between the actual control signal effected on plant and the output of controller in historical moment. For the controlled system with unknown or slowly varying parameters, the networked feedback correction algorithm is discussed based on a modified recursive least-squares identi cation algorithm. The system stability is analyzed and the simulation results show that the time delay in the networked control system can be accurately compensated. The excellent network performance is ensured with this strategy.     

适用于语音业务的MANET机会路由机制

传统路由机制需要在源和目的节点之间预先建立端到端路径,当链路质量较差时,频繁地建立路径会影响业务的服务质量。为支持实时语音业务,提出一种机会路由机制,该机制并不预先建立连接,而利用多个路由请求和路由应答消息建立转发列表,表中的节点利用与其他节点的相遇机会对数据包进行转发,并根据转发节点的优先级对转发数据包的数量进行限制。仿真结果表明：机会路由机制能够减小语音业务的端到端时延,提高分组投递率,可以在不稳定的信道为语音业务提供服务质量保证。     

Hierarchical self-localization of underwater wireless sensor network nodes

The follow-up application of underwater wireless sensor network is influenced by accuracy of self-localization of nodes. The self-localization of nodes is discussed in this paper. First of all, nodes of underwater wireless sensor network are classified into several levels according to the accuracy of position of nodes and the levels are from the first to the fifth in accordance with accuracy of nodes from high to low respectively. Secondly, the level of anchor nodes can be known by those unknown nodes from the information given by the anchor nodes themselves, At the same time the unknown nodes are able to be located in the area controlled by the first level of anchor nodes that are as the aggregation. Then the positioning algorithm is designed correspondingly in accordance with the accuracy level of nodes. Finally, the positioning algorithm is simulated and analyzed. The result shows that the unknown nodes can be located effectively by hierarchical control.     

模糊控制系统的垂直切换判决算法分析

针对模糊控制系统中切换时延较长和切换次数较多的问题,研究了一种基于模糊控制系统的垂直切换判决算法。在基于信号强度判决时将RSS作为门限值,提高系统判决能力;同时,将网络参数和服务类型作为判决因素,结合层次分析法引入并行的模糊控制系统,缩短了切换判决的时间、选择适合用户的最佳网络,做出垂直切换。仿真结果表明,该算法减少了切换次数,降低了切换时延,增强了系统的性能。与传统的切换算法相比较,该算法对切换的判决因素考虑的更全面,兼顾了用户终端的使用环境及成本问题,有效地保证了网络的服务质量。     

农业大棚嵌入式无线温控系统设计

为了有效实施农业大棚温度动态实时监控,提出采用Zigbee无线网络和Linux嵌入式操作系统设计大棚温度监控系统。系统采用C/S结构设计,分为下位机和上位机2部分。下位机系统分为温度采集节点和汇聚节点,温度采集节点完成大棚内不同地点的温度信息采集和无线数据传输功能;汇聚节点除了完成数据中继任务外,还可根据上位机反馈的控制指令完成排风扇的打开或电热系统的开启工作;服务器端的上位机系统完成数据的储存和分析,并根据分析结果完成对下位机系统的实时控制。实践证明,该系统可精确监控大棚温度,有效降低布线成本,有助于降低劳动成本和提高农作物产量。     

ABT处理和插穗长度对栝楼扦插苗质量的影响

栝楼是雌雄异株植物,在人工栽培过程中,扦插快繁技术能有效控制雌雄株合适比例;本试验研究了ABT不同浓度（0mg/l、50 mg/l、100 mg/l和200 mg/l）、100 mg/l浓度时不同浸泡时间（10min、20 min、40 min和60 min）和不同插穗长度（1节、2节和3节）对扦插生根率和移栽成活率的影响。实验结果表明：在用珍珠岩做基质时,栝楼扦插快繁适合的条件是：选用当年生的2节插穗,用100mg/l浓度的ABT粉浸泡40分钟;该处理条件下,插穗具有100%的生根率和99%的移栽成活率以及较好的综合经济效益     

用回归方程预测和控制储藏谷物品质稳定性的探讨

为较准确地识别和衡量储藏过程中谷物早期的劣变及其程度，防止、控制或延缓不良变化的发生，根据对国内外有关资科的研究分析，总结归纳出安全水分、温度变化、湿度变化、平衡水分、水活度的回归方程及控制指标，以预测和控制储藏谷物品质的稳定性．     

Temperature Control System of the Polish Liquid on Cool Machining Optics Components

In order to improve productiveness, the liquid temperature should be maken arrive predetermine value as short time as impossible, and controlling accuracy should be ensured at the same time. For the purpose, an optimum scheme of dynamic heating in all process is presented. The power of electronic stove is chosen according began and end temperature,volume of the heated object, for which the paper established the optimum control model of dynamic heating. Based on the model, the system has been manufactured. The experimental results show that the system is better in fast temperature rising,small over adjusting and high precision.     

园黄梨气调贮藏研究初报

研究了气调指标对园黄梨贮藏效果的影响。结果表明，气调贮藏可抑制梨果实呼吸作用，减少果实消耗，保持硬度，并有利于提高果实品质。适宜的气体组合可延缓果实衰老，防止果实褐变且延长贮藏期。5％O2＋0％～1％CO2是长期贮藏园黄梨的理想气体指标。     

壳寡糖处理对草莓贮藏品质的影响

以草莓为试材,果实采后,分别用质量分数为1.0%,1.5%,2.0%的壳寡糖溶液浸泡处理草莓果实1min,研究壳寡糖处理对草莓贮藏品质的影响。结果表明,壳寡糖处理能较好地保持贮藏草莓的感官品质、风味品质、营养品质;能有效调节、控制果肉细胞的成熟与衰老,从而延长果实贮藏期。质量分数1.5%壳寡糖处理果实的各项品质指标均优于其他处理组,是有效延长草莓果实贮藏时间的最佳浓度。     

真空冷冻脱水胡萝卜预处理工艺及干燥特性的研究

胡萝卜是一种营养物质含量丰富,人们喜食的蔬菜产品。为解决常压热风干燥技术生产的出口脱水胡萝卜营养物质损失严重和色泽差等产品质量问题,系统研究了胡萝卜在真空冷冻干燥条件下的预处理工艺及干燥特性。研究结果表明,胡萝卜真空冷冻干燥最佳工艺参数为:85℃下漂烫75s,体积分数为0.15%的VC+体积分数为0.09%的柠檬酸中护色10min,装载总量100g,装载厚度为6mm下真空冷冻干燥10.4h。在最佳操作条件下获得的胡萝卜产品颜色损失小,质量较佳。     

基于ZigBee的工厂化水产养殖溶解氧在线监控系统设计的研究

为了采用分散控制方式对工厂化水产养殖溶解氧进行监控,提出了基于ZigBee的溶解氧在线监控系统。系统采用集散控制模式,分为终端节点、路由节点和网关节点以及监控中心4个层次。终端节点采集养殖池中溶氧量,然后通过路由节点汇聚到网关节点,并根据溶氧量对与之连接的增氧机进行控制。网关节点将所有终端节点数据传输给监控中心,并接收监控中心的控制指令,进而通过各终端节点控制增氧机。同时,监控中心对数据进行存储、统计和分析,并产生控制指令。ZigBee节点采用CC2430作为核心芯片,使用ZigBee2006协议栈实现无线网络节点之间的通信。结果表明：该系统稳定性较好,部署灵活、容易扩展,满足了工厂化水产养殖的要求。实现了对溶解氧的在线实时监测及对增氧机的有效控制,降低了养殖成本。     

辣椒红色素的超临界萃取

为了制备高质量的辣椒红色素,用正交实验设计对有机溶剂浸提辣椒油树脂及超临界CO2流体技术提纯辣椒红色素的工艺条件进行优化筛选。结果表明,制备辣椒油树脂的最佳工艺条件为：丙酮作有机溶剂,辣椒粉末细度为40目,固液比为1∶6,浸提时间40min;辣椒油树脂提纯辣椒红色素的超临界萃取条件为：萃取釜温度35℃,萃取压力30MPa,时间2.0h。有机溶剂浸提和超临界萃取结合使用可有效地提高辣椒红色素的色价与质量。     

A radial basis function neural network based self adapting predictive decoupling control system for gas collector pressure in coke ovens

Pressure is measured at different levels in the loop layer because self adapting predictive decoupling control systems are strongly coupled, disturbed, and non linear and there is a long time delay for gas collector pressure systems in coke ovens. By combing the traditional neural network control and proportional integral differential(PID) controllers based on radial basis function(RBF) neural network identification, the gas collector pressure is ensured to reach the desired technology range. The prediction model of an RBF neural network is used for advanced prediction of the actual output pressure to overcome delays in general gas collection. The simulation results and application indicate that the method can obtain ideal control results.     

A Kind of Synthetical Fuzzy Control System of Carburization

Carburization is a complex manufacturing process with serious disturbance and time delay,which is multi-variable and uncertain.It is difficult to set up an exact mathematic model.Moreover,by means of conventional control methods and experience,satisfying control result can't be obtained.In this paper,according to the characteristic of controlled-object,Fuzzy control method has been chosen to design a Fuzzy-PI controller and a mixed-PID Fuzzy controller.The result of simulation shows that the robust performance and control result of the new Fuzzy controllers is better than the conventional PID controller.The overshoot is smaller.It is helpful to improve the quality of carburizing workpieces.     

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.     

Research on immunization strategies based on independent sets of complex networks

According to the concept of independent set, this paper proposes a new immunization strategy of complex networks which immunizes the nodes in an independent set with maximum degree, called targeted immunization in the independent set. When the total degree of immune nodes in independent set is equal to the total degree of targeted immunization nodes in the whole network, the immunization strategy of independent set is more effective than the targeted immunization strategy of the whole network. Based on the network structure, this paper explains the reason. Comparing the random immunization of independent sets with the random immunization in the whole network, test results indicate that more nodes do not be removed with high degree for the random immunization of independent sets. For classic susceptible-infected(SI) model, all nodes in the network are only two states: susceptible or infected. In the study of immunization strategies, comparing SI model with SIR, SIS models. The use of SI model will be more favorable.     

冷等离子体结合气调包装对杨梅贮藏品质的影响

以云南东魁鲜杨梅为试验材料,以未进行冷等离子体处理和气调包装处理的杨梅果实为对照,分别采用单独冷等离子体、单独气调包装及冷等离子体结合气调对杨梅进行处理,探究冷等离子体结合气调包装处理对杨梅贮藏品质的影响。结果表明:冷等离子体结合气调包装处理可显著降低杨梅果实初始菌落数,贮藏期间能较好地抑制菌落总数的增长,对杨梅色泽无明显影响,能显著延缓可溶性固形物含量的下降,保持较高的好果率;其还可抑制杨梅超氧化物歧化酶(SOD)活性的下降,延缓果实的氧化损伤和品质劣变;冷等离子体结合气调包装处理时,冷等离子体处理时间越长,保鲜效果越好。该研究可为杨梅的贮藏保鲜提供理论参考。     

微真空贮藏延缓西兰花采后衰老与黄化的机制

为探讨微真空贮藏条件延缓西兰花采后衰老黄化的机制,以新鲜西兰花为试验材料,在(3±0.5)℃,55~65 kPa微真空条件下贮藏,以相同温度下的常压贮藏为对照,探讨采后西兰花的营养与质地指标及色泽指标与叶绿体超微结构的变化。结果表明：与对照相比,微真空贮藏条件能有效抑制采后西兰花Vc、可滴定酸、可溶性固形物含量的下降,延缓脆度的下降及咀嚼性的升高;抑制叶绿素含量的下降及黄化指数的升高,延缓叶绿体超微结构的解体。本研究表明,微真空贮藏条件一方面通过抑制西兰花营养品质的下降及质地品质的变化延缓西兰花的采后衰老;另一方面,通过抑制西兰花色泽品质的变化及叶绿体超微结构的解体延缓西兰花的采后黄化进程。