Seismic performance evaluation of VCFPB isolated storage tank using real-time hybrid simulation

Variable curvature friction pendulum bearings(VCFPB)effectively reduce the dynamic response of storage tanks induced by earthquakes.Shaking table testing is used to assess the seismic performance of VCFPB isolated storage tanks.However,the vertical pressure and friction coefficient of the scaled VCFPB in the shaking table tests cannot match the equivalent values of these parameters in the prototype.To avoid this drawback,a real-time hybrid simulation(RTHS)test was developed.Using RTHS testing,a 1/8 scaled tank isolated by VCFPB was tested.The experimental results showed that the displacement dynamic magnification factor of VCFPB,peak reduction factors of the acceleration,shear force,and overturning moment at bottom of the tank,were negative exponential functions of the ratio of peak ground acceleration(PGA)and friction coefficient.The peak reduction factors of displacement,acceleration,force and overturning moment,which were obtained from the experimental results,are compared with those calculated by the Housner model.It can be concluded that the Housner model is applicable in estimation of the acceleration,shear force,and overturning moment of liquid storage tank,but not for the sliding displacement of VCFPBs.

Research on Optimal Configuration of Energy Storage in Wind-Solar Microgrid Considering Real-Time Electricity Price

Capacity allocation and energy management strategies for energy storage are critical to the safety and economical operation of microgrids.In this paper,an improved energymanagement strategy based on real-time electricity price combined with state of charge is proposed to optimize the economic operation of wind and solar microgrids,and the optimal allocation of energy storage capacity is carried out by using this strategy.Firstly,the structure and model of microgrid are analyzed,and the outputmodel of wind power,photovoltaic and energy storage is established.Then,considering the interactive power cost between the microgrid and the main grid and the charge-discharge penalty cost of energy storage,an optimization objective function is established,and an improved energy management strategy is proposed on this basis.Finally,a physicalmodel is built inMATLAB/Simulink for simulation verification,and the energy management strategy is compared and analyzed on sunny and rainy days.The initial configuration cost function of energy storage is added to optimize the allocation of energy storage capacity.The simulation results show that the improved energy management strategy can make the battery charge-discharge response to real-time electricity price and state of charge better than the traditional strategy on sunny or rainy days,reduce the interactive power cost between the microgrid system and the power grid.After analyzing the change of energy storage power with cost,we obtain the best energy storage capacity and energy storage power.

Improvement Design for Distributed Real-Time Stream Processing Systems

In the era of Big Data, typical architecture of distributed real-time stream processing systems is the combination of Flume, Kafka, and Storm. As a kind of distributed message system, Kafka has the characteristics of horizontal scalability and high throughput, which is manly deployed in many areas in order to address the problem of speed mismatch between message producers and consumers. When using Kafka, we need to quickly receive data sent by producers. In addition, we need to send data to consumers quickly. Therefore, the performance of Kafka is of critical importance to the performance of the whole stream processing system. In this paper, we propose the improved design of real-time stream processing systems, and focus on improving the Kafka's data loading process.We use Kafka cat to transfer data from the source to Kafka topic directly, which can reduce the network transmission. We also utilize the memory file system to accelerate the process of data loading, which can address the bottleneck and performance problems caused by disk I/O. Extensive experiments are conducted to evaluate the performance, which show the superiority of our improved design.

Joint Algorithm of Message Fragmentation and No-Wait Scheduling for Time-Sensitive Networks

Time-sensitive networks(TSNs)support not only traditional best-effort communications but also deterministic communications,which send each packet at a deterministic time so that the data transmissions of networked control systems can be precisely scheduled to guarantee hard real-time constraints.No-wait scheduling is suitable for such TSNs and generates the schedules of deterministic communications with the minimal network resources so that all of the remaining resources can be used to improve the throughput of best-effort communications.However,due to inappropriate message fragmentation,the realtime performance of no-wait scheduling algorithms is reduced.Therefore,in this paper,joint algorithms of message fragmentation and no-wait scheduling are proposed.First,a specification for the joint problem based on optimization modulo theories is proposed so that off-the-shelf solvers can be used to find optimal solutions.Second,to improve the scalability of our algorithm,the worst-case delay of messages is analyzed,and then,based on the analysis,a heuristic algorithm is proposed to construct low-delay schedules.Finally,we conduct extensive test cases to evaluate our proposed algorithms.The evaluation results indicate that,compared to existing algorithms,the proposed joint algorithm improves schedulability by up to 50%.

Confidentiality-aware message scheduling for security-critical wireless networks

Without considering security, existing message scheduling mechanisms may expose critical messages to malicious threats like confidentiality attacks. Incorporating confidentiality improvement into message scheduling, this paper investigates the problem of scheduling aperiodc messages with time-critical and security-critical requirements. A risk-based security profit model is built to quantify the security quality of messages; and a dynamic programming based approximation algorithm is proposed to schedule aperiodic messages with guaranteed security performance. Experimental results illustrate the efficiency and effectiveness of the proposed algorithm.

Efficiency analysis of numerical integrations for finite element substructure in real-time hybrid simulation

Finite element（FE） is a powerful tool and has been applied by investigators to real-time hybrid simulations（RTHSs）. This study focuses on the computational efficiency, including the computational time and accuracy, of numerical integrations in solving FE numerical substructure in RTHSs. First, sparse matrix storage schemes are adopted to decrease the computational time of FE numerical substructure. In this way, the task execution time（TET） decreases such that the scale of the numerical substructure model increases. Subsequently, several commonly used explicit numerical integration algorithms, including the central difference method（CDM）, the Newmark explicit method, the Chang method and the Gui-λ method, are comprehensively compared to evaluate their computational time in solving FE numerical substructure. CDM is better than the other explicit integration algorithms when the damping matrix is diagonal, while the Gui-λ（λ = 4） method is advantageous when the damping matrix is non-diagonal. Finally, the effect of time delay on the computational accuracy of RTHSs is investigated by simulating structure-foundation systems. Simulation results show that the influences of time delay on the displacement response become obvious with the mass ratio increasing, and delay compensation methods may reduce the relative error of the displacement peak value to less than 5% even under the large time-step and large time delay.

Design and development of real-time query platform for big data based on hadoop

This paper designs and develops a framework on a distributed computing platform for massive multi-source spatial data using a column-oriented database(HBase).This platform consists of four layers including ETL(extraction transformation loading) tier,data processing tier,data storage tier and data display tier,achieving long-term store,real-time analysis and inquiry for massive data.Finally,a real dataset cluster is simulated,which are made up of 39 nodes including 2 master nodes and 37 data nodes,and performing function tests of data importing module and real-time query module,and performance tests of HDFS's I/O,the MapReduce cluster,batch-loading and real-time query of massive data.The test results indicate that this platform achieves high performance in terms of response time and linear scalability.

Security System in United Storage Network and Its Implementation

With development of networked storage and its applications, united storage network (USN) combined with network attached storage (NAS) and storage area network (SAN) has emerged. It has such advantages as high performance, low cost, good connectivity, etc. However the security issue has been complicated because USN responds to block I/O and file I/O requests simultaneously. In this paper, a security system module is developed to prevent many types of attacks against USN based on NAS head. The module not only uses effective authentication to prevent unauthorized access to the system data, but also checks the data integrity. Experimental results show that the security module can not only resist remote attacks and attacks from those who has physical access to the USN, but can also be seamlessly integrated into underlying file systems, with little influence on their performance.

IPC Mechanisms in Satellite Real-Time Microkernel Operating System

One of the most important features of modem minor satellites is to realize autonomous moving. The perfomance of the satellite autonomous computer operating system acting as the control center is of utrnost importance. The recent trend in operating system development is adopting microkernel architecture that holds such advantages as microminiaturization, modularity, portability and extendibility. IPC is the key of microkernel design. Message-based IPC mechanism is generally used in existing microkernel Operating system. It is of consistency, safety and reliability.However, it can not provide efficient support for real-time applications in satellite systems and it only applies to loose coupling multi-processor architecture. In this paper, an improvement solution for existing message-based IPC is proposed at first to obtain real-time performance. Then a new IPC mechanism is designed. It particulary applies to shared memory tight coupling multi-processor architecture.

Research on the Security of the United Storage Network Based on NAS

A multi-user view file system (MUVFS) and a security scheme are developed to improve the security of the united storage network (USN) that integrates a network attached storage (NAS) and a storage area network (SAN). The MUVFS offers a storage volume view for each authorized user who can access only the data in his own storage volume, the security scheme enables all users to encrypt and decrypt the data of their own storage view at client-side, and the USN server needs only to check the users’ identities and the data’s integrity. Experiments were performed to compare the sequential read, write and read/write rates of NFS+MUVFS+secure_module with those of NFS. The results indicate that the security of the USN is improved greatly with little influence on the system performance when the MUVFS and the security scheme are integrated into it.

IOTA-Based Data Encryption Storage and Retrieval Method

At present,the traditional blockchain for data storage and retrieval reflects the characteristics of slow data uploading speed,high cost,and transparency,and there are a lot of corresponding problems,such as not supporting private data storage,large data operation costs,and not supporting Data field query.This paper proposes a method of data encryption storage and retrieval based on the IOTA distributed ledger,combined with the fast transaction processing speed and zero-value transactions of the IOTA blockchain,through the Masked Authenticated Messaging technology,so that the data is encrypted in the data stream.The form is stored in the distributed ledger,quickly retrieved through the field index mechanism established by the data form,and the data operation is carried out on the chain.Experimental results show that this system has high storage,encryption and retrieval performance,and good practicability.

An On-Line Scheduler over Hard Real-Time Communication System

By thorough research on the prominent periodic and aperiodic scheduling algorithms,anon-line hard real-time scheduler is presented,which is applicable to the scheduling of packets over a link.This scheduler,based on both Rate Monotonic,pinwheel scheduling algorithm Sr and Polling Serverscheduling algorithms,can rapidly judge the schedulability and then automatically generate a bus tablefor the scheduling algorithm to schedule the packets as the periodic packets.The implementation of thescheduler is simple and easy to use,and it is effective for the utilization of bus link.The orderly executionof the bus table can not only guarantee the performance of the hard real time but also avoid the blockageand interruption of the message transmission.So the scheduler perfectly meets the demand of hard real-time communication system on the field bus domain.

Average Current Control with Internal Model Control and Real-time Frequency Decoupling for Hybrid Energy Storage Systems in Microgrids

Among hybrid energy storage systems(HESSs),battery-ultracapacitor systems in active topology use DC/DC power converters for their operations.HESSs are part of the solutions designed to improve the operation of power systems in different applications.In the residential microgrid applications,a multilevel control system is required to manage the available energy and interactions among the microgrid components.For this purpose,a rule-based power management system is designed,whose operation is validated in the simulation,and the performances of different controllers are compared to select the best strategy for the DC/DC converters.The average current control with internal model control and real-time frequency decoupling is proposed as the most suitable controller according to the contemplated performance parameters,allowing voltage regulation values close to 1%.The results are validated using real-time hardware-in-the-loop(HIL).These systems can be easily adjusted for other applications such as electric vehicles.

即时通讯软件电子数据取证的法律规制

为应对我国存在的取证技术滞后于侦查需要、软件服务商协助义务缺乏补偿机制、电子数据取证与隐私保护失衡、证据保管链不完善等问题,可以通过提升侦查人员的取证能力、构建软件服务商协助义务补偿机制、保障公民隐私的合法权益、完善证据的保全措施等方式以适应即时通讯软件电子取证的复杂环境。

基于Chord算法的可扩展高性能元数据存储环设计

Hazel Nut是一个基于块的分级存储系统,为满足该系统元数据内存需求量大、访问速度快、动态可增长的要求,设计并实现一种可扩展高性能的元数据存储环SCRing。SCRing由元数据存储环shell ring、映射环chord ring和缓存表组成,shell ring与chord ring分别用于存储与定位数据块元数据信息,缓存表用于缓存数据块元数据在内存中的位置。通过消息摘要算法计算得到SCRing双环节点间的映射关系。依据SCRing对消息摘要算法的实际需求,结合Linux内核版本,测试并比较Linux内核支持的消息摘要算法的速度、均匀性和稳定性,得出SCRing所应采用的算法种类和使用模式,并在此基础上对SCRing读写性能进行验证,结果表明SCRing具备可扩展性和高性能,满足Hazel Nut系统元数据访问需求。

基于北斗卫星通信的林区小气候监测系统研究

为实现无手机信号林区生态系统参数的实时监测,基于北斗卫星短报文、物联网和云存储等技术,设计了一种林区小气候实时监测系统。该系统由小气候监测站、云服务器和系统软件构成,可实现林区大气、土壤、光照和植物等多参量的实时监测、云存储、动态查询、报表生成和大数据分析。系统对森林火险天气指标的计算进行平滑处理,加入了枯枝落叶层土壤湿度火险因子,实现了森林火险天气等级预报功能,为局部林区的防火预警服务。通过2017年3—5月在北京鹫峰国家森林公园的连续测试实验,3个小气候监测站可以稳定可靠地获取11种林区小气候数据,北斗卫星传输正确率分别为98.57%、99.43%和99.59%,达到了对林区小气候进行长期实时监测的目的,通信费用低于铱星卫星通信。该系统自2016年在北京、内蒙古、河北和河南等地推广应用,为林区的生态大数据获取和分析提供服务。

草莓和番茄果实乙烯自我催化与Ca^(2+)-CaM的关系

外源乙烯处理乳白期草莓和绿熟期番茄果实 12h后 ,诱导草莓乙烯大量合成 ,使番茄乙烯释放高峰提前 2d出现 ,同时还促进两种果实的钙调素 (Calmodulin ,CaM)含量增加。细胞质膜钙离子通道阻塞剂异搏定 (Verapamil,Vp)、钙调素拮抗剂氯丙嗪 (Chloropromaize ,CPZ)和三氟拉嗪 (Trifluoperazine ,TFP)均抑制了外源乙烯诱导的草莓乙烯合成 ,表明Ca2 + CaM信使系统可能参与草莓乙烯自我催化作用 ;Vp抑制外源乙烯诱导的番茄乙烯合成 ,而CPZ和TFP的作用不显著 ,说明番茄果实乙烯自我催化作用与胞外Ca2 + 内流有关 ,与CaM的关系不明显。

我院药品冷链监控平台的建立与应用

目的:确保医院冷链药品储存设备可靠,保证在院冷藏药品的质量。方法:介绍我院药品冷链监控平台的建立、应用效果和相关的改进及完善措施。结果:通过配备相关的设备、架构平台网络、确定监测点、设置系统中的预警条件等,建立了我院药品的冷链监控平台,实现了对医院不同区域、不同冷链设备温湿度的全天候实时监控,可实时了解设备的运行状况、提供完整的在院药品冷藏温度记录,借助预警短信及时处理设备故障问题;通过预警短信原因分析及时更换了不合格设备,并进一步完善了冷链监控平台的使用制度与流程。在平台应用的2年内,53台普通冰箱更换为药品专用冰箱;月度预警短信数和冷藏设备预警率分别由2014年9月短信预警功能开启初期的6 869条、100%下降至2016年2月的1 083条、40%。结论:医院药品冷链监控平台的建立,保障了冷藏药品储存环境的可靠性,从而确保了在院冷藏药品的质量。

基于分布式缓存的消息中间件存储模型

消息中间件的存储模型对中间件性能影响极大。基于此,分析消息中间件的多种存储模型原理,并通过性能测试对各种存储模型进行比对分析。分布式缓存在读写速度和扩展性上较传统存储方式有较大优势。在传统存储模型的基础上,提出一种基于分布式缓存的消息中间件存储模型。实现基于该模型的原型系统,并通过性能测试数据证明该模型的可行性。

基于分布式框架的气象预报服务系统

随着气象现代化的不断发展,气象服务产品不断丰富,气象观测数据呈现爆炸式增长,各种气象服务系统集约化程度较低,系统并发访问、处理及检索显示效率较低。因此,建立集约、高效的预报服务系统成为业务发展的迫切需求。文中提出了气象预报服务系统,该系统采用Nginx+Apache应用方案,Storm分布式数据处理技术,Cassandra和HBase分布式数据存储技术,RabbitMQ消息队列统一数据分发技术,分别针对网页负载均衡、动静分离响应,大数据分布式并发预处理,数据分类分布式存储,跨平台、高效、可靠的数据分发等服务进行优化设计,实现了针对长江流域、省、市、县用户的高并发、高处理能力、高可靠性的预报服务系统。该系统的建成极大地提高了气象预报、服务的工作效率,为今后的气象业务发展提供了较好的基础平台。