An Efficient Crash Recovery Technique for Real-Time Main Memory Database

This paper presents an efficient recovery scheme suitable for real-time mainmemory database. In the recovery scheme, log records are stored in non-volatile RAM which is dividedinto four different partitions based on transaction types. Similarly, a main memory database isdivided into four partitions based data types. When the using ratio of log store area exceeds thethreshold value, checkpoint procedure is triggered. During executing checkpoint procedure, someuseless log records are deleted. During restart recovery after a crash, partition reloading policyis adopted to assure that critical data are reloaded and restored in advance, so that the databasesystem can be brought up before the entire database is reloaded into main memory. Therefore downtime is obvionsly reduced. Simulation experiments show our recovery scheme obviously improves thesystem performance, and does a favor to meet the dtadlints of real-time transactions.

Validation concurrency control protocol in parallel real-time database systems

In parallel real-time database systems, concurrency control protocols must satisfy time constraints as well as the integrity constraints. The authors present a validation concurrency control(VCC) protocol, which can enhance the performance of real-time concurrency control mechanism by reducing the number of transactions that might miss their deadlines, and compare the performance of validation concurrency control protocol with that of HP2PL(High priority two phase locking) protocol and OCC-TI-WAIT-50(Optimistic concurrency control-time interval-wait-50) protocol under shared-disk architecture by simulation. The simulation results reveal that the protocol the author presented can effectively reduce the number of transactions restarting which might miss their deadlines and performs better than HP2PL and OCC-TI-WAIT-50. It works well when arrival rate of transaction is lesser than threshold. However, due to resource contention the percentage of missing deadline increases sharply when arrival rate is greater than the threshold.

A dynamic crash recovery scheme for distributed real-time database systems

Recovery performance in the event of failures is very important for distributed real-time database systems. This paper presents a time-cognizant logging-based crash recovery scheme （TCLCRS） that aims at distributed real-time databases, which adopts a main memory database as its ground support. In our scheme, each site maintains a real-time log for local transactions and the subtransactions, which execute at the site, and execte local checkpointing independently. Log records are stored in non-volatile high- speed store, which is divided into four different partitions based on transaction classes. During restart recovery after a site crash, partitioned crash recovery strategy is adopted to ensure that the site can be brought up before the entire local secondary database is reloaded in main memory. The partitioned crash recovery strategy not only guarantees the internal consistency to be recovered, but also guarantee the temporal consistency and recovery of the sates of physical world influenced by uncommitted transactions. Combined with two- phase commit protocol, TCLCRS can guarantee failure atomicity of distributed real-time transactions.

Conception and Implementation of Geographical Database for Cultural Heritage Management—Case of Historical Jeddah, KSA

Saudi Arabia is attempting to develop a long-term tourism business that respects Islamic ideals, heritage, and traditions. In accordance with the “Vision of the Kingdom of Saudi Arabia 2030”, significant emphasis has been placed on developing and promoting cultural tourism as a result of the Kingdom’s very valuable civilizational and cultural heritage, in addition to entertainment and improving the quality of life. The city of Jeddah in the Kingdom of Saudi Arabia’s second capital, and the district known as “Al-Balad”, which is located in the city’s core, is a historical neighborhood known for its old structures and multi-story houses. Since 1947, the historical monuments in the Al-Balad region have faced major and challenging issues as a result of neglect and a failure to maintain them. To protect this historical architectural heritage, the United Nations Educational, Scientific, and Cultural Organization (UNESCO) has designated Jeddah’s historic area as a World Heritage Site. The purpose of this research is to identify historical sites in the city of Al-Balad using existing maps, field surveys, and the design and creation of a spatial database that can be used with geographic information systems (GIS). By combining the results of the spatial database and photographic surveys with the history of Old Jeddah, an application was created and made available to users and those interested in the Internet that can be used through mobile devices (mobile phones and tablets) to introduce the historical area of Jeddah and promote tourism in Old Jeddah.

Real-Time Memory Data Optimization Mechanism of Edge IoT Agent

With the full development of disk-resident databases(DRDB)in recent years,it is widely used in business and transactional applications.In long-term use,some problems of disk databases are gradually exposed.For applications with high real-time requirements,the performance of using disk database is not satisfactory.In the context of the booming development of the Internet of things,domestic real-time databases have also gradually developed.Still,most of them only support the storage,processing,and analysis of data values with fewer data types,which can not fully meet the current industrial process control system data types,complex sources,fast update speed,and other needs.Facing the business needs of efficient data collection and storage of the Internet of things,this paper optimizes the transaction processing efficiency and data storage performance of the memory database,constructs a lightweight real-time memory database transaction processing and data storage model,realizes a lightweight real-time memory database transaction processing and data storage model,and improves the reliability and efficiency of the database.Through simulation,we proved that the cache hit rate of the cache replacement algorithm proposed in this paper is higher than the traditional LRU(Least Recently Used)algorithm.Using the cache replacement algorithm proposed in this paper can improve the performance of the system cache.

An Efficient Secure Real-Time Concurrency Control Protocol

Secure real-time databases must simultaneously satisfy two requirements in guaranteeing data security and minimizing the missing deadlines ratio of transactions. However, these two requirements can conflict with each other and achieve one requirement is to sacrifice the other. This paper presents a secure real-time concurrency control protocol based on optimistic method. The concurrency control protocol incorporates security constraints in a real-time optimistic concurrency control protocol and makes a suitable tradeoff between security and real-time requirements by introducing secure influence factor and real-time influence factor. The experimental results show the concurrency control protocol achieves data security without degrading real-time perform ance significantly.

Research on Real-time Data Sharing in Power Integrated Automation System

The Power Integrated Automation System has a large amount of the real-time data, it needs to achieve data sharing in different modules in its own system, sometimes even needs to be shared with the other systems. The thesis discusses the characteristics and the ways of the real-time data sharing in the first place. Then, it compares the merits and drawbacks in different ways. Besides, it gives a viable resolution in different aspects, such as the design of the real-time database, the framework of the communication system and the design of the communication software, as well as the real-time data sharing in different systems.

国土调查历史与现状数据一体化整合建库探讨——以东莞为例

通过历史国土调查数据库和现状国土调查数据库建设,解决了不同年份的国土调查数据成果存储分散、应用难度大的问题,建立了多时期、全聚合、覆盖全面、统一更新的国土调查数据库,实现了涵盖一调、二调、三调3个时期的土地利用数据库和数据资源管理体系。国土调查历史与现状数据一体化数据库的建设有效提升了国土调查数据成果的利用价值和历史价值,为全市自然资源业务协同和相关部门的管理工作提供了重要数据支撑。

ArcSDE支持的鞍山市历史文化空间数据模型构建与应用

为解决鞍山市历史文化资源管理与保护工作中存在的家底不清、位置不明、挖掘不深等实际问题,设计并构建历史文化空间数据模型,旨在从宏观视角对全市历史文化资源进行统一管理。在调研数据使用需求的基础上,设计专题图层体系,完善数据库逻辑结构;完成数据编辑入库后,基于ArcSDE技术设计了鞍山市历史文化空间数据存储与访问模式。提出了鞍山市历史文化资源空间数据模型构建技术方案,在数据维护与管理、历史文化资源展示体系构建以及辅助决策与强化历史文化资源保护力度3个方面进行应用。结果表明:ArcSDE支持的鞍山市历史文化空间数据模型构建技术方案能切实满足空间数据使用需求,并能有效解决传统历史文化空间数据模型存在的应用深度不足、服务大众能力较弱、数据维护困难、数据网络化访问能力缺失等问题。该方案能够为鞍山市历史文化资源的开发利用与保护管理提供较强的技术支撑。

生产信息化建设实时历史数据库平台iHistorian

系统阐述了实时历史数据库iHistorian在生产信息化建设中的应用以及与关系型数据库的差别

PREMONITORY DEPENDENCY OF HISTORICAL DATABASE AND ITS MATHEMATICAL PROPERTIES

To process the data with strong historical features, such as data in earthquake research,weather forecast, medical records and census, a new mathematical model of historical datasystem is proposed. This model can be characterized as ' relational database with timemark + histotical rule base = historical database', and it is easy to implement. The formaldescription of historical database and a special class of historical rules-premonitory de-pendency (abbreviated as PD)-are discussed, the poperties and inference axioms of PDare investigated. The soundness and completeness of the axioms are proved. The problemsabout the true-set of historical rules, such as the problems of emptyness, infiniteness,equivalence and containment are proved to be undecidable.

The Multi-level Recovery of Main-memory Real-time Database Systems with ECBH

Storing the whole database in the main-memory is a common method to processreal-time transaction in real-time database systems. The recovery mechanism of Main-memory Real-timeDatabase Systems (MMRTDBS) should reflect the characteristics of the main-memory database andreal-time database because their structures are quite different from other conventional databasesystems. In this paper, therefore, we propose a multi-level recovery mechanism for main-memoryreal-time database systems with Extendable Chained Bucket Hashing (ECBH). Owing to the occurrence ofreal-time data in real-time systems, we should also consider it in our recovery mechanism .According to our performance test, this mechanism can improve the transaction concurrency, reducingtransactions ' deadline missing rate.

An IoT-Based Aquaculture Monitoring System Using Firebase

Indonesia is a producer in the fisheries sector,with production reaching 14.8 million tons in 2022.The production potential of the fisheries sector can be optimally optimized through aquaculture management.One of the most important issues in aquaculture management is how to efficiently control the fish pond water conditions.IoT technology can be applied to support a fish pond aquaculture monitoring system,especially for catfish species(Siluriformes),in real-time and remotely.One of the technologies that can provide this convenience is the IoT.The problem of this study is how to integrate IoT devices with Firebase’s cloud data system to provide reliable and precise data,which makes it easy for fish cultivators to monitor fishpond conditions in real time and remotely.The IoT aquaculture fishpond monitoring use 3 parameters:(1)water temperature;(2)pHwater level;and(3)turbidity level of pond water.IoT devices use temperature sensors,pH sensors,and turbidity sensors,which are integrated with a microcontroller and Wi-Fi module.Data from sensor readings are sent to the Firebase cloud via theWi-Fi module so that it can be accessed in real time by end users with an Androidbased mobile app.The findings are(1)the IoT-based aquaculture monitoring system device has a low error rate in measuring temprature,pH,and turbidity with a percentage of 1.75%,1.94% and 9.78%,respectively.Overall,the total average error of the three components is 4.49%;(2)in cost analysis,IoT-based has a cost-effectiveness of 94.21% compared to labor costs.An IoT-based aquaculture monitoring system using Firebase can be effectively used as a technology for monitoring fish pond conditions in real-time and remotely for fish cultivators that contribute to providing an IoT-based aquaculture monitoring system that produces valid data,is precise,is easy to implement,and is a low-cost system.

基于GIS的开封市城市更新价值评估方法研究

当前我国城镇化将进入以提升质量为主的转型发展新阶段,城市发展也逐步转变其发展方式。不再一味地向外扩张,而是转向调整内部结构,注重内部更新,提高城市质量和承载能力,控制增量,盘活存量、优化存量。在存量规划背景下的城市更新也通过方式的转变将越来越令人重视。文章通过用GIS手段对历史文化名城——开封的城市更新进行问题探讨与方法的研究,以定量与定性方式相结合,对收集到的数据进行综合整理分析,对开封市现存文保单位进行收集整理,构建整体保护系统,进行针对性与实践意义的研究,为开封市城市更新提供科学的依据。

基于大数据理论的小电流接地故障推拉策略的研究

小电流接地系统广泛应用于我国35 kV及以下电压等级的配电网络,在中低压等级的配电网络中最常出现的故障为单相接地故障。通过整理小电流接地系统发生单相接地故障时的历史数据库,在大数据视野下发现发生单相接地故障的规律,并对多数据故障样本进行分析比对,得出各个因素对于接地故障的影响程度,从而在系统同一母线元件发生接地时根据数据信息分析出母线上各个出线的故障概率,提高故障推拉精度,缩小停电范围。

基于实时数据库系统的历史数据处理

实时数据库(RTDB)是传统数据库技术与实时系统相结合的产物,是厂级信息监控系统(SIS)的核心。历史数据是系统定时从实时数据库中采样,保存到历史数据库中的数据,用户需要时可随时从历史数据库中访问历史数据。历史数据库包含内存历史数据库和磁盘历史数据库。内存历史数据库关注的是测点近期数据的组织方式;磁盘历史数据库管理的对象是历史数据文件和管理信息文件。对磁盘历史数据库的文件结构、缓冲区进行了描述,并详细阐述了其总体架构及重要功能模块(读/写操作、压缩、数据页存取)的实现技术。

基于实时数据的风力发电机组性能在线评价

在分析常规风电机组出力特性评价方法的基础上,探讨了评价过程中存在的诸多问题。介绍了一种通过实时/历史数据库获取风电场相关生产数据,并将所得数据换算成标准条件下的环境工况值,进行实时在线计算。通过自动绘制风电机组风速-电功率的特性曲线,结合标定的额定设计值,对实际运行结果数据进行离散度偏差比较,从而实时监测和评价风电机组在某段时间内和当前时期内的运行性能。

历史环境变化数据库的建设与应用

阐述了历史环境变化数据库的资料来源及其计算机化的规范 ;介绍了以计算机、数据库等为技术手段的历史环境变化数据库的建设方案及数据库的主要功能 ;

组态王相关数据库研究

主要从数据库的角度介绍了组态王软件,包括组态王的数据库技术、SQL访问功能。此外通过相关数据库的比较介绍,系统分析了组态王软件所支持的各种数据库,及随着组态王版本升级添加的历史数据库功能。分析比较相关数据库与历史数据库的差异,为从事组态王开发的研究人员提供参考和启发。

历史航空影像数字化与建库技术初探

历史航空影像客观有效地记录了自然景观与人文景观的演化变迁过程,是人类进行资源环境问题研究和改造客观现实世界的基础信息资源,从而为社会进步和可持续发展提供科学的决策支持。针对历史航空影像数字化与数据库建设工作的技术要求,通过对历史航空影像资料数字化作业规程的分析与探讨,给出了实用有效的历史航空影像数字化作业流程和技术指标,进而提出了切实可行的数字化历史航空影像建库技术路线和解决方案,并以历史航空影像数字化与建库试验研究验证了技术方案的合理性和可操作性,为历史航空影像数据库的建设提供前期的试验指导。