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.

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.

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.

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.

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.

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。

时空数据的安全存储与完整性验证

针对时空数据的高效存储和安全管理问题,设计一种基于Hadoop分布式文件系统(Hadoop distributed file system,HDFS)的大数据安全存储架构,选用商用密码系列算法中的SM3密码杂凑算法,保证客户端与服务端信息交互的完整性,并在SM3算法的基础上结合消息鉴别码算法(HMAC),设计并实现一种基于SM3-HMAC的时空数据完整性验证方案。实验结果表明:本文设计的验证方案是行之有效的,在满足效率要求的同时可为时空数据的安全存储和完整性验证提供一种安全有效的解决方案。

Research on medical data storage and sharing model based on blockchain

With the process of medical informatization,medical diagnosis results are recorded and shared in the form of electronic data in the computer.However,the security of medical data storage cannot be effectively protected and the unsafe sharing of medical data among different institutions is still a hidden danger that cannot be underestimated.To solve the above problems,a secure storage and sharing model of private data based on blockchain technology and homomorphic encryption is constructed.Based on the idea of blockchain decentralization,the model maintains a reliable medical alliance chain system to ensure the safe transmission of data between different institutions;A privacy data encryption and computing protocol based on homomorphic encryption is constructed to ensure the safe transmission of medical data;Using its complete anonymity to ensure the Blockchain of medical data and patient identity privacy;A strict transaction control management mechanism of medical data based on Intelligent contract automatic execution of preset instructions is proposed.After security verification,compared with the traditional medical big data storage and sharing mode,the model has better security and sharing.

基于MD5数据库加密的企业档案信息数据安全存储方法

当前企业档案信息数据安全存储映射关系多为单向,存储效率较低,导致定向存储效率较低,为此提出了基于信息摘要算法5(Message-digest Algorithm 5,MD5)数据库加密的企业档案信息数据安全存储方法。文章根据实际的存储需求及标准,采集存储信息数据,以多阶的方式,提高存储效率,设计多阶加密存储映射。文章构建MD5数据库加密安全存储模型,采用高密压缩实现安全存储。经过4个小组的测定,得出设计的定向存储效率均可达90%以上,说明该种档案数据信息存储方法的应用效果较佳,存储效率及质量较高,具有实际的应用价值。

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。