Dynamic channel reservation scheme based on priorities in LEO satellite systems

According to low earth orbit（LEO） satellite systems with users of different levels, a dynamic channel reservation scheme based on priorities is proposed. Dynamic calculation of the thresholds for reserved channels is the key of this strategy. In order to obtain the optimal thresholds, the traffic is predicted based on the high-speed deterministic movement property of LEO satellites firstly. Then, a channel allocation model based on Markov is established. Finally, the solution of the model is obtained based on the genetic algorithm. Without user location, this strategy effectively reduces handover failures and improves channel utilization by adjusting dynamically the thresholds according to traffic conditions. The simulation results show that the system＇s overall quality of service can be improved by this strategy.

A New Design of Dynamic Priority Planning on CAN for Wire Harness Assembly Machine

The specific features of the CAN bus is analyzed and the functional performances in the Controller Area Network (CAN) bus system of Wire Harness Assembly Machine (WHAM) is discussed. A reasonable definition of application layer which is not defined in the CAN specification is given for the control system of WHAM. So application layer planning of CAN bus for dynamic priority is presented. With the mechanism of dynamic priority,it becomes easily to find out the error nodes in the CAN bus system of WHAM and realize multi-mode operation.

Bus Priority Control for Dynamic Exclusive Bus Lane

One problem with the existing dynamic exclusive bus lane strategies is that bus signal priority strategies with multi-phase priority request at intersections are not adequately considered.The principle of bus signal priority level was designed based on the isolated multi-phase structure principle consideration of the bus signal priority,and a new priority approach for the dynamic exclusive bus lane was proposed.Two types of priority strategies,green extension and red truncation,were proposed for current phase and next phase buses,respectively.The control parameters including minimum green time,green extension time,maximum green time and bus arrival time are calculated.The case studies for this paper were carried out using four consecutive intersections of Huaide Middle Road in Changzhou City.The signal control scheme was designed using the conventional,exclusive bus lane method,the dynamic exclusive bus lane without signal priority method,and the proposed approach,respectively.The authors used the VISSIM simulation platform to evaluate the efficiency of each approach.Results showed that the method of approach can significantly decrease delays caused by social and conventional buses and make up for the negative impact social buses have on the bus rapid transit(BRT)operation,which allows the method to complement the dynamic,exclusive bus lane design.

QoS-Aware and Resource-Efficient Dynamic Slicing Mechanism for Internet of Things

With the popularization of terminal devices and services in Internet of things(IoT),it will be a challenge to design a network resource allocation method meeting various QoS requirements and effectively using substrate resources.In this paper,a dynamic network slicing mechanism including virtual network(VN)mapping and VN reconfiguration is proposed to provide network slices for services.Firstly,a service priority model is defined to create queue for resource allocation.Then a slice including Virtual Network Function(VNF)placement and routing with optimal cost is generated by VN mapping.Next,considering temporal variations of service resource requirements,the size of network slice is adjusted dynamically to guarantee resource utilization in VN reconfiguration.Additionally,load balancing factors are designed to make traffic balanced.Simulation results show that dynamic slicing mechanism not only saves 22%and 31%cost than static slicing mechanism with extending shortest path(SS_ESP)and dynamic slicing mechanism with embedding single path(DS_ESP),but also maintains high service acceptance rate.

Extended Sequential Truncation Technique for Adaptive Dynamic Programming Based Security-Constrained Unit Commitment with Optimal Power Flow Constraints

Considering the economics and securities for the operation of a power system, this paper presents a new adaptive dynamic programming approach for security-constrained unit commitment (SCUC) problems. In response to the “curse of dimension” problem of dynamic programming, the approach solves the Bellman’s equation of SCUC approximately by solving a sequence of simplified single stage optimization problems. An extended sequential truncation technique is proposed to explore the state space of the approach, which is superior to traditional sequential truncation in daily cost for unit commitment. Different test cases from 30 to 300 buses over a 24 h horizon are analyzed. Extensive numerical comparisons show that the proposed approach is capable of obtaining the optimal unit commitment schedules without any network and bus voltage violations, and minimizing the operation cost as well.

A Hybrid Model Predictive Control for Handling Infeasibility and Constraint Prioritization

A hybrid approach using MLD (mixed logical dynamical) framework to handle infeasibility and constraint prioritization issues in MPC (model predictive control) based on input-output model is introduced. By expressing constraint priorities as propositional logics and by transforming the propositional logics into inequalities,the infeasibility and constraint prioritization issues are solved in the MPC. Constraints with higher priorities are met first, and then these with lower priorities are satisfied as much as possible. This new approach is illustrated in the control of a heavy oil fractionator-Shell column. The overall control performance has been significantly improved through the infeasibility and control priorities handling.

Design of task priority model and algorithm for imaging observation problem

In the imaging observation system, imaging task scheduling is an important topic. Most scholars study the imaging task scheduling from the perspective of static priority, and only a few from the perspective of dynamic priority. However,the priority of the imaging task is dynamic in actual engineering. To supplement the research on imaging observation, this paper proposes the task priority model, dynamic scheduling strategy and Heuristic algorithm. At first, this paper analyzes the relevant theoretical basis of imaging observation, decomposes the task priority into four parts, including target priority, imaging task priority, track, telemetry & control(TT&C)requirement priority and data transmission requirement priority, summarizes the attribute factors that affect the above four types of priority in detail, and designs the corresponding priority model. Then, this paper takes the emergency tasks scheduling problem as the background, proposes the dynamic scheduling strategy and heuristic algorithm. Finally, the task priority model,dynamic scheduling strategy and heuristic algorithm are verified by experiments.

Method of the left-turning bus priority at intersections based on a variable lane

To reduce the delay of left-turning buses and improve the traffic efficiency at signalized intersections,a novel variable bus approach lane(VBAL)control method based on bus pre-signals is proposed.This method combines the variable lane with the bus priority pre-signal,and realizes the left-turning bus priority without causing great impact on other vehicles.To validate the effectiveness of the method,the VBAL scheme was compared with the single left-turn lane scheme(SLTL)and the double left-turn lane scheme(DLTL).On this basis,the delay change calculation model of left-turning buses and through vehicles were established by the cumulative curve graphic method.The influence of vehicle proportion and green split on the model was studied through sensitivity analysis.The results show that VBAL can reduce the delay of left-turning bus and the increase of through vehicle delay to the greatest extent.Finally,the scheme was applied to a real-world intersection,and the results demonstrate the effectiveness and advantage of the VBAL scheme.

Indoor biology pollution control based on system-based humidity priority control strategy

Indoor biological contamination and HVAC system secondary contamination problems caused wide public concerns. Biological contamination control will be the next step to achieve better IAQ. The most efficient and safe way to control biological contamination was to limit relative humidity in HVAC system and conditioned environment in the range that is more unsuitable for microorganism to survive. In this paper,by referring to bio-clean project experiences,a system-based humidity priority control manner came into being by lowering outdoor air humidity ratio to eliminate all indoor latent load and using self recirculation units to bear indoor sensible load. Based on the whole-course residue humidity contaminant control concept,dynamic step models for coil and conditioned zone were developed to describe mass and energy conservation and transformation processes. Then,HVAC system and conditioned zone dynamic models were established on LabVIEW+Matlab platform to investigate optimized regulation types,input signatures and control logics. Decoupling between cooling and dehumidification processes can be achieved and a more simplified and stable control system can be acquired by the system-based humidity priority control strategy. Therefore,it was a promising way for controlling biological pollution in buildings in order to achieve better IAQ.

Large-Scale Weather Systems: A Future Research Priority

A brief assessment is provided of both the case against and the case for assigning priority to research on large-scale weather systems （LSWS）. The three-fold case against is based upon： the emergence of new overarching themes in environmental science; the fresh emphasis upon other sub-disciplines of the atmospheric science; and the mature state of research and prediction of LSWS. The case for is also supported by three arguments. First is the assertion that LSWS research should not merely be an integral but a major component of future research related to both the new overarching themes and the other sub-disciplines. Second recent major developments in LSWS research, as epitomized by the paradigm shifts in the prediction strategy for LSWS and the emergence of the potential vorticity perspective, testify to the theme＇s on-going vibrancy. Third the field＇s future development, as exemplified by the new international THORPEX （The Observing System Research and Predictability Experiment） programme, embodies a perceptive dovetailing of intellectually challenging fundamental research with directed application（s） of societal and economic benefit. It is thus inferred that LSWS research, far from being in demise, will feature at the forefront of the new relationship between science and society.

An IEEE 802.3 Compatible Real Time Medium Access Control with Length-based Priority

A new medium access control method is proposed over the predominant Ethernet broadcast channel. Taking advantages of intrinsic variable length characteristic of standard Ethemet frame, message-oriented dynamic priority mechanism is established. Prioritized medium access control operates under a so-called block mode in event of collisions. High priority messages have a chance to preempt block status incurred by low priority ones. By this means, the new MAC provides a conditional detrministic real time performance beyond a statistical one. Experiments effectiveness and attractiveness of the proposed scheme.Moreover,this new MAC is completely compatible with IEEE802.3 .

蚁群融合动态窗口法的分布式多机器人运动规划研究

为更好地协调分布式多移动机器人在动态环境下的运动,将蚁群算法与动态窗口法相融合构造多机器人系统,并利用优先级策略来化解运动冲突。为提升多机器人全局路径的综合最优性能,提出了多指标寻优的启发式函数和信息素更新策略来提升蚁群的寻优能力,通过冗余点删除策略进一步提升路径质量;融合蚁群与动态窗口法构造机器人运动学模型,通过自适应导航策略来提升未知环境下机器人的局部运动能力;将单机器人避障策略和多移动机器人优先级策略相结合,将多机器人路径规划简化为单个移动机器人的动态路径规划问题。仿真实验结果表明,所提方法能够实现多移动机器人系统在未知环境中的协同避障,具有较高的安全性。

考虑需求响应优先级的配电终端虚拟电厂优化调度研究

虚拟电厂技术提升了分布式能源消纳潜力、填补了电网调度盲区。为引导用户参与电力调度,在激励型需求响应购电协议基础上,构建了包含智能家居负荷和冷热联供建筑相变储能系统的虚拟储能模型,并量化分析各类资源可调度裕度;以用户响应特性为指标,采用熵权法评估各类用户负荷的动态响应性能,设置虚拟储能参与调度的动态响应优先级;以虚拟电厂收益最大为目标,综合考虑资源购电成本、电热平衡等因素,提出了集分布式电源和智慧社区激励响应负荷的终端虚拟电厂优化调度模型,采用改进光线寻优算法对模型求解。结果验证了所提方法的有效性。

多级智慧供应链网络节点动态优先级排序系统

多级智慧供应链网络中的节点错排问题,使得数据信息的传输受到影响,导致节点动态优先级排序精准度较低。为此,设计了多级智慧供应链网络节点动态优先级排序系统。在多级SDN拓扑网络中,确定供应链节点的排列方式,完成多级智慧供应链网络的一般性结构设计。对网络节点实施无标度处理,根据动态参数标准化执行结果,计算优先级特征向量与排序介数的取值范围,实现对节点对象的排序处理,完成多级智慧供应链网络节点动态优先级排序系统的设计。实验结果表明,设计系统作用下,能够有效解决多级智慧供应链网络中的节点错排问题,提高多级智慧供应链网络节点动态优先级排序精准度。

生产调度与可靠性耦合的变工况再制造系统维护建模

针对变工况下的多工序再制造系统,提出生产、设备衰退和系统维护之间的耦合建模方法.首先引入考虑设备可靠性的动态生产优先级并据此生成生产调度计划,进而基于变动生产计划建立设备的变工况故障率模型,在此基础上,考虑生产的动态性和设备衰退的不确定性,构建基于双生产周期优化的再制造系统动态维护决策模型.算例分析表明,该模型可有效提高系统生产净收益且相对于传统生产和维护决策方法更具优势.

效率、安全与增长:产业发展多重目标的矛盾与协调

一国或地区的产业发展经常追求效率、安全与增长等多重目标,这三者既有统一性也有矛盾性,难以同时兼顾,形成产业发展的“不可能三角”。理论研究表明:如果选择效率与增长的组合,则难以兼顾产业安全;选择安全与增长的组合,则难以兼顾分工效率;选择效率与安全的组合,则难以兼顾经济增长。空间及动态分析进一步表明,几种组合的选择因为形势变化在不同国家或地区而变得更为复杂。因此,不同国家或地区需因时因地制宜,根据自身条件在不同时期选择不同的应对策略,按照“动态优先目标排序”原则,力求更好统筹效率、安全与增长,促进本国或本地区产业更加平稳健康发展。

基于居民舒适度的差异化家庭器具水资源配置

居民用水舒适度差异化使得传统“一刀切”的水分配方案不仅无法满足家庭差异化用水需求,还导致水资源浪费。针对上述问题,文章提出基于居民舒适度的差异化家庭器具用水调度模型与算法。揭示居民家庭器具用水习惯与用水舒适度的关系,并根据居民用水习惯对家庭器具进行分类,同时建立不同类型器具的节水率区间,根据家庭器具二维动态优先级划分不同类型居民的用水舒适度,联合不同类型居民舒适度和不同种类器具节水率构建基于居民舒适度的用水配置数学模型。为高效求解数学模型,提出了一种改进的原子搜索算法(improved atomic search algorithm,IASO),仿真结果显示了在不同类型居民用水舒适度下家庭器具的用水量。对居民器具用水进行细化研究,为建立节水舒适型家庭提供参考。

Transfer-based Approximate Dynamic Programmingfor Rolling Security-constrained Unit Commitment with Uncertainties

This paper studies the rolling security-constrained unit commitment(RSCUC)problem with AC power flow and uncertainties.For this NP-hard problem,it is modeled as a Markov decision process,which is then solved by a transfer-based approximate dynamic programming(TADP)algorithm proposed in this paper.Different from traditional approximate dynamic programming(ADP)algorithms,TADP can obtain the commitment states of most units in advance through a decision transfer technique,thus reducing the action space of TADP significantly.Moreover,compared with traditional ADP algorithms,which require to determine the commitment state of each unit,TADP only needs determine the unit with the smallest on-state probability among all on-state units,thus further reducing the action space.The proposed algorithm can also prevent the iter-ative update of value functions and the reliance on rolling forecast information,which makes more sense in the rolling decision-making process of RSCUC.Finally,nu-merical simulations are carried out on a modified IEEE 39-bus system and a real 2778-bus system to demonstrate the effectiveness of the proposed algorithm.

快速功率波动下大型定/变速机组的响应特性研究

本文对定速机组和变速机组应对快速功率波动时的响应情况进行了对比仿真,研究了九种不同大小、不同频率的功率波动下定速机组和变速机组的响应情况,并利用功率差的平均值、标准值、功率上升(下降)响应时间的平均值、功率延迟时间这四个量化评估指标对定速机组和变速机组的功率响应特性进行了具体分析。结果表明变速机组不仅能有效应对秒级时间内快速波动的新能源出力,对快速新能源出力波动的响应能力也远优于传统定速机组,进一步说明了变速机组应对新能源波动的有效性。

Raft存储集群中的日志分发机制优化

在分布式存储系统中,Raft(replicated and fault tolerant)算法的强领导特性在节点数量增多时会带来巨大的日志分发开销,限制了系统性能和水平扩展能力。针对系统性能和扩展性瓶颈,提出了两种新的日志机制来优化一致性哈希集群分布式存储方案。第一种是基于动态优先级的日志分发机制,日志分发顺序由领导者与跟随者节点日志的同步程度决定,加快了日志项的提交速度;第二种是基于窗口流水线的日志分发机制,领导者节点指派日志同步程度较高的跟随者节点对同步程度较低的跟随者节点进行日志分发,缩短了系统中节点日志趋向一致的时间。相比于未优化方法,吞吐量和日志同步时间在多节点集群上有显著提升,证明了两种日志机制在改进系统性能上的有效性。