Test and Experiment Study on Synchronous Cooperative Design System Over Networked Manufacturing Platform

Based on the analysis on the previous research in virtual manufacturing and virtual enterprises,this paper pro- vides a novel architecture of networked manufacturing system around the cooperative design.The key technologies for synchronous cooperative design in networked manufacturing platform,such as the cooperative mechanism,cooperative rules,control authority conveyed,cooperative efficiency,are detailed,with which a synchronous cooperative design system is developed.Due to the cooper- ative efficiency is the major bottleneck of the synchronous cooperative design over Internet,this research details the test and experi- ment to demonstrate the practicality of the system.Finally the advantages of the system are illustrated compared with current soft- ware tools.

SET-MRTS:An Empirical Experiment Tool for Real-Time Scheduling and Synchronization

In the real-time scheduling theory,schedulability and synchronization analyses are used to evaluate scheduling algorithms and real-time locking protocols,respectively,and the empirical synthesis experiment is one of the major methods to compare the performance of such analyses.However,since many sophisticated techniques have been adopted to improve the analytical accuracy,the implementation of such analyses and experiments is often time-consuming.This paper proposes a schedulability experiment toolkit for multiprocessor real-time systems(SET-MRTS),which provides a framework with infrastructures to implement the schedulability and synchronization analyses and the deployment of empirical synthesis experiments.Besides,with well-designed peripheral components for the input and output,experiments can be conducted easily and flexibly on SET-MRTS.This demonstration further proves the effectiveness of SET-MRTS in both functionality and availability.

The Present Status and Future of Research of the East Asian Monsoon

The weather and climate in China are greatly affected by the East Asian monsoon. For long time the Chinese meteorologists have undertaken numerous works regarding research and prediction of the East Asian monsoon, and made great achievements that are well noted for the world and in China. In the future 5-10 years, the research on the East Asian monsoon will be strengthened and the thus obtained achievements will be gradually transferred into the operational capability, eventually leading to an improvement of weather and climate prediction in East Asia. The present paper has firstly made an overview of the present status of research on the East Asian monsoon, illustrating the 4-stage developmental process of monsoon study in China and major achievements thus obtained. Then the major problems related to the study of the East Asian monsoon are scientifically indicated, and the monsoon-related ongoing and future scientific field experiments and study projects the Chinese scientists have initiated or participated are briefly described. It may be expected that a new breakthrough in the problem of the East Asian monsoon in the future ten years will be made with these efforts and intensive research works. Finally, it is pointed out that, to accomplish this new breakthrough, a key problem is to carry out the extensive cooperation, in particular the scientific cooperation of the scientist across the Taiwan Strait as well as countries over the surrounding regions.

Practice and Enlightenment for International Cooperation on Chang’e 4 Mission

On January 3,2019,the first lunar farside in-situ exploration mission,China’s Chang’e 4(CE-4),successfully landed in Von Karman crater within the South Pole-Aitken(SPA)basin.The CE-4 mission provided a host platform and opened its science payload resources to the international community.Science payloads from Germany,Sweden,the Netherlands and Kingdom of Saudi Arabia were aboard CE-4.It has explored effective models of international cooperation,accumulated cooperation experience,and provided a reference for the implementation of broader and deeper cooperation in major projects.This paper summarizes the practical experience of international cooperation on CE-4,analyzes the difficulties and existing problems of science payloads management,explains the current management methods,and puts forward suggestions for the development of broader international cooperation for the future.

Exploring the Difficulties and Challenges of the Local Macao English Language Learners towards the Online Synchronous One-on-one English Learning Class

With the development of technology,the number of English learners who opt for online learning has been increasing.In the past,students had a tendency to download English materials and watch online videos for improving their English skills.Recently,thanks to a shift to online learning,students have been making more use of online synchronous oneon-one English classes to improve their English at leisure.Although this type of learning mode is becoming more and more popular,the study of the difficulties and challenges of English learners in such a field has been under-explored.This study attempts to use a qualitative approach to interview two English learners of different backgrounds to better understand the difficulties and challenges they encountered when using such a learning method.The two interviewees conclude points ranging from the learning aspect,distant feeling,signal delay,instability of the learning software and hardware that lead to technical problems.Certain measures to avoid the problems are also suggested in this paper.

基于分布式天线协同的OFDM粗定时同步方法

在频率选择性衰落信道中,两根分布式接收天线接收来自单天线发射机的发射信号。利用两根分布式接收天线的协同,提出了一种协同的粗定时同步方法。该方法在不增加各分布式接收天线预定虚警概率的情况下,通过两根分布式接收天线的协同,避免了部分漏检情况的发生。分析和仿真结果表明,提出的方法可以改善OFDM系统粗定时同步的正确检测和漏检性能。

短波信道对OFDM信号的影响研究

短波信道的多径效应,频率偏移,非线性干扰等因素会降低短波OFDM通信的性能。文章通过理论推导,分析了短波信道对OFDM技术的影响。通过计算机仿真实际的短波通信实验,验证了分析的结果。

Optimal design of FRMSM to decrease detent force

An optimal configuration of the flux-reversal linear synchronous motor (FRLSM) with the optimal number of attachment permanent magnets (PMs) was presented. The optimal model of 2 000 N was designed to reduce the detent force by redesigning the air-gap structure and skewing. The design parameters,mover PMs and stator core,were selected for optimal design by DOE. The thrust and the detent force of the designed optimal models were compared by finite element analysis (FEA). As a result,the thrust of the optimal model is slightly decreased by 1.97% compared with the basic model,and the detent force of the optimal model is greatly decreased by 88.47% compared with the basic model.

International Experience of Farmers Specialized Cooperative Economic Organizations in Marketing of Agricultural Products

In the world,development modes of farmers specialized cooperative economic organizations mainly includes two types:( i) specialized agricultural cooperatives with the United States of America as representative,and( ii) comprehensive agricultural cooperatives with Japan and South Korea as representative. In comparison,China mainly develops farmers specialized cooperatives which are agricultural production with family as unit and small in land and management scale like agricultural production in Japan. Therefore,in marketing of agricultural products,cooperatives in the United States of America and Japan have successful experience. China may learn such experience in the development of farmers specialized cooperatives.

Robot Position Control Using Force Information for Cooperative Work in Remote Robot Systems with Force Feedback

This paper proposes robot position control using force information for cooperative work between two remote robot systems with force feedback in each of which a user operates a remote robot by using a haptic interface device while observing work of the robot with a video camera. We also investigate the effect of the proposed control by experiment. As cooperative work, we deal with work in which two robots carry an object together. The robot position control using force information finely adjusts the position of the robot arm to reduce the force applied to the object. Thus, the purpose of the control is to avoid large force so that the object is not broken. In our experiment, we make a comparison among the following three cases in order to clarify how to carry out the control effectively. In the first case, the two robots are operated manually by a user with his/her both hands. In the second case, one robot is operated manually by a user, and the other robot is moved automatically under the proposed control. In the last case, the object is carried directly by a human instead of the robot which is operated by the user in the second case. As a result, experimental results demonstrate that the control can help each system operated manually by the user to carry the object smoothly.

Generalized PIC Detector for Distributed STBC under Quasi-Synchronization

In this paper, we propose a Generalized Parallel Interference Cancelation (G-PIC) approach for the detection of D-STBC under Quasi-Synchronization in the case of any number of relay nodes with just statistical information about time misalignment. While as, most researches assume perfect synchronization between the relay nodes for the detection of D-STBC which is hard to achieve. This approach proved to be very effective to mitigate the degradation in the system performance due to the imperfect synchronization. The numerical simulations, for the proposed approach, showed that in just three iterations we can achieve performance close to the D-STBC with perfect synchronization.

Water Allocation Strategies: Experimental Evidence from Uzbekistan

Irrigation water is a scarce common-pool resource in Uzbekistan, which leads to an increasing competition over its allocation among farmers. We examine how the management of this resource affects individual strategic behavior and how its availability (vis-a-vis scarcity vs. non-scarcity) impacts cooperation. We conduct a field experiment in Uzbekistan where two policies are analyzed: penalty and bonus. Our findings suggest that both penalty and bonus mechanisms are effective in reducing individual water appropriation compared to the case in which these policies are absent. However, in terms of reducing overall water appropriation, the bonus mechanism is the most effective in preserving the resource stock. Therefore, policymakers should have a degree of flexibility regarding the selection of a mechanism to reduce water consumption. We also find that subjects exhibit different appropriation behaviors depending on their location within the irrigation system, with upstream users being more sensitive to water reduction than downstream users.

美国社区学院产学研合作教育的经验与启示

美国产学研合作教育起步较早,积累了丰富的办学实践经验,具有完善的法律保障体系和灵活多样的合作方式,形成了独特的办学模式。尤其是社区学院的校企合作教育,有效促进了美国地方社会经济的发展。美国社区学院的校企产学研合作教育经历了形成、发展、成熟和繁荣四个时期,在服务地方社会经济和人才培养方面取得了显著成效,积累了丰富的成功经验:一是建立健全法律制度,为开展产学研合作教育提供保障;二是建立政府、社区学院和企业多元协作体系,推动校企产学研合作良性运转;三是依托项目群推动社区学院与企业开展深度合作,搭建校企产学研合作教育的桥梁;四是形成社区学院与企业联合培养人才模式,搭建校企产学研合作教育的纽带;五是满足地方社会经济发展的需求,抓住校企产学研合作教育的生命线。我国地方高校应借鉴美国社区学院发展的经验,充分发挥地方高校与企业之间的优势资源,健全校企产学研合作教育的法律体系,建立产学研合作教育一体化发展模式与管理机制,依托项目推动地方高校校企产学研合作教育,推动地方社会经济发展。

PSCAD的发电机准同期并列综合实验设计

针对电力系统自动化实验教学中存在的不足,设计了同步发电机准同期并列综合实验。实验模型采用PSCAD/EMTDC,建立了包含发电机及并网系统、原动机及其调速器、励磁系统、准同期并列控制单元、电压向量的动态显示等关键部件。依托实验模型设计了循序渐进的教学实验项目,主要有机组启动与并网的验证性实验、不同并列条件影响的分析性实验、频率差和电压差调节的设计性实验。该实验将电路、电机学、自动控制理论、电力系统分析等多门专业核心课程贯穿起来,提升了学生综合运用知识解决复杂工程问题的能力。

协同创新理论下中国国家实验室建设路径探索——基于美国能源部国家实验室的经验启示

为推进中国国家实验室的开放和协同创新,运用协同创新理论,基于对美国能源部国家实验室协同创新的实践经验分析,结合中国当前面临被西方主要国家技术封锁的严峻形势,探讨协同创新促进中国国家实验室建设的路径。协同创新包含了多方创新主体、共同目标、优势互补和合理分工、复杂的相互作用和整体协同效应等五方面的核心要素,其结构从简单无序布局向高级有序组织变革转变为网络化创新结构,因此要确保协同创新成果实现,需要充分考虑不同主体之间的利益平衡和风险控制等因素。美国能源部国家实验室具有明确的战略目标与使命、充足的财政投入与多元化经费来源、高效的管理运行机制、人员组成多元化的强大科研团队,其发展总体呈现开放化、网络化的对外合作趋势,在协同创新方面形成了强化战略导向和目标聚焦、深化产学研合作、建立高效的协同机制、强化人才培养和团队建设,以及鼓励创新、营造宽容失败的文化氛围等经验举措。借鉴美国经验,深化国际合作和加强内部合作是应对挑战、促进国家实验室建设的两翼。因此,应对当前西方国家技术封锁,中国国家实验室建设须毫不动摇地坚持开放共享与合作交流的理念,强化顶层设计与政策引导,深化产学研用合作,建立高效协同机制,实现多领域协同创新、引领学科交叉创新,并积极融入创新联合体建设,弘扬科学家精神、营造鼓励创新探索的科研文化氛围。

农机具田间试验动态遥测系统设计

针对当前农机具田间试验参数检测技术薄弱、无法全面综合评估农机关键部件作业性能的情况,设计了农机具田间试验的遥测系统。在当前农机具三点悬挂连接方式利用上拉杆拉压力传感器、下悬挂销剪切力传感器、角传感器、动态扭矩传感器等实现机具作业过程中的多分量力有效检测。系统检测终端采用STM32F429单片机为主核心芯片,设计了多通道传感器数据融合同步采集处理电路、以太网处理电路及外部输出电路等,可实时对前端传感器数据进行采集、处理及存储,并采用RTK差分定位系统准确检测机组的作业速度及位置,通过大功率WiFi模块经局域网络将作业参数实时传输给田间远程监测平台。用户可通过上位机软件实现对作业参数进行计算存储、曲线绘制、时域分析、统计设置等。测试结果表明:系统结构简单,检测精度高,能够实现机具作业同步受力分析及技术参数测量,可作为田间试验的有效检测手段。