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.

Weak Serializable Concurrency Control in Distributed Real-Time Database Systems

Most of the proposed concurrency control protocols for real time database systems are based on serializability theorem. Owing to the unique characteristics of real time database applications and the importance of satisfying the timing constraints of transactions, serializability is too strong as a correctness criterion and not suitable for real time databases in most cases. On the other hand, relaxed serializability including epsilon serializability and similarity serializability can allow more real time transactions to satisfy their timing constraints, but database consistency may be sacrificed to some extent. We thus propose the use of weak serializability(WSR) that is more relaxed than conflicting serializability while database consistency is maintained. In this paper, we first formally define the new notion of correctness called weak serializability. After the necessary and sufficient conditions for weak serializability are shown, corresponding concurrency control protocol WDHP(weak serializable distributed high priority protocol) is outlined for distributed real time databases, where a new lock mode called mask lock mode is proposed for simplifying the condition of global consistency. Finally, through a series of simulation studies, it is shown that using the new concurrency control protocol the performance of distributed real time databases can be greatly improved.

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.

Real-TimeSQL的设计与实现

实时数据库的结构化查询语言RTSQL(Real-TimeSQL)是实时数据库研究的一项重要内容。论文详细论述了RTSQL的一种设计方法,即扩展SQL92标准以支持实时数据库的要求,构建RTSQL语言的方法。文章还介绍了RTSQL在Agilor实时数据库系统中的实现方式。在文章最后给出了RTSQL进一步研究的思路和建议。

Cache-Conscious Index Mechanism for Main-Memory Databases

Recent studies have addressed that the cache be havior is important in the design of main memory index structures. Cache-conscious indices such as the CSB^＋-tree are shown to outperform conventional main memory indices such as the AVL-tree and the T-tree. This paper proposes a cacheconscious version of the T-tree, CST-tree, defined according to the cache-conscious definition. To separate the keys within a node into two parts, the CST-tree can gain higher cache hit ratio.

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.

The Organizing of Database from Surlari National Geomagnetic Observatory

Our paper describes the organizing of database,remarks about SNGO(Surlari National Geomagnetic Observatory)and network infrastructure.Based on the geomagnetic data acquired and stored on the database server,we perform the processing and analysis of geomagnetic parameters through different spectral,statistical and correlation methods.All these parameters are included in the geomagnetic database on server.The web interface for the database meets the different needs of handling the data collected,raw or processed.The server-side programming language used for design is php.This allow us to select different periods for which access to stored data,required for different search filters and different parameters or data from different time periods can be compared.For a more in-depth analysis of the stored data,through JavaScript programming language graphs for different parameters can be drawn.Access to the web interface can be done with or without authentication,depending on the need to ensure the security of certain data collected,stored and processed.The applications are scalable for different devices that will access it:mobile,tablets,laptops or desktops.

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.

实时数据库数据的批量写入及性能测试研究

通过对石油化工行业使用较多的PHD实时数据库在多模式下的数据批量写入,以标准差指标对测试值进行可信度分析、测试调校,得出多模式下实时数据批量修改、更新测试的最优结果,探索一种行之有效的工业实时数据库优化、应用的方法。

卷烟滤棒成型加工区域集控系统实现

针对滤棒成型作业区分散、设备种类多、制造厂家和数量多、接口协议复杂且不统一以及海量数据变量难识别等问题,设计并开发了基于OPC UA架构和实时内存数据库的就地滤棒加工区数采和监控系统。自主开发OPC服务器,实现了滤棒成型主、辅设备的实时数据采集,并通过高效内存数据库服务器对生产及设备信息进行海量存储,进而实现了对滤棒成型车间生产过程信息的全面、准确迁移集成,以及对滤棒生产、产量、质量、机台效率、设备状态等信息的可视化区域集控。

基于区域健康医疗大数据脑卒中专病库的构建在中医药研究中的应用

目前国内基于区域诊疗数据构建的单病种数据库在中医药领域应用较少,本研究依托天津健康医疗大数据平台建立脑卒中专病库,探讨区域诊疗数据从形成专病库到深入挖掘临床问题所具有的独特优势和缺陷,为后续中医药领域区域诊疗数据下专病库的构建和应用提供参考。专病库构建需要经过跨机构数据采集、整合和治理,同时需兼顾数据安全,以此作为研究开展基础。建设完成后通过描述人群现状和预后情况,总结专病库概况和可开展的研究方向。最后对研究中数据治理、分析时存在的问题和解决方案进行梳理,从方法学角度讨论专病库应用与中医药研究的适配性。专病库覆盖天津市81家医院2016~2020年24万首发脑卒中患者诊疗数据,并链接公卫系统死亡登记数据,可进行人群特征分析、发病影响因素探查、诊疗路径优化、预测模型构建和卫生经济学研究。但也存在数据覆盖度不全和记录不完善的问题,并伴随真实世界研究中常出现的各种偏倚,需要在研究设计及方法学应用上加以调整。真实世界下的诊疗数据应用是探索和提升中医药疗效的必由之路,但正如脑卒中专病库展现出的研究优势和不足,数据挖掘是循序渐进的过程,需要通过将研究需求反哺于临床电子病历的记录以提升专病库质量,为承载后续更多高质量的中医药研究奠定基础。

不动产统一登记数据整合关键技术研究

围绕不动产登记数据整合的痛点难点进行展开研究,详细介绍了不动产登记数据整合内容和技术路线,基于ArcEngine开放平台,从用户需求出发,设计开发不动产登记数据整合平台,并利用某地区不动产登记数据整合项目对该平台的适用性和可靠性进行验证,极大地提高了不动产登记数据整合效率,为不动产登记数据的信息化管理奠定了基础。

北京市不动产登记数据深度治理研究与实践

开展不动产登记数据深度治理,不断提升不动产登记数据质量,是持续推进不动产登记领域改革与创新的必然要求。本文结合不动产登记数据库标准和北京市实际数据情况,深入分析不动产登记数据,从空间、资源、权利的维度构建以地、幢、户为主要检查对象的数据检查指标体系。通过治理数据库和数据深度治理系统建设,选取部分数据检查指标,检查不动产登记数据质量,进行数据深度治理实践。通过制定数据检查指标,解决了历史遗留的房屋现势权利重复、逻辑关联关系完整性不强和不动产单元编码不规范方面的数据问题,提升了不动产登记数据质量,为北京市经济社会发展提供重要的基础数据保障。

电磁能系统智能运维实时数据处理关键技术及应用

为应对电磁能运维实时数据管理系统在大规模、分布式和异构化业务场景下面临的挑战,首先在综合考虑各类电磁能系统运维实时数据特征和实时数据管理需求的基础上,结合内存非关系型键值数学模型,构建了以数据为中心的电磁能实时数据处理流程;然后,针对电磁能系统各业务软件与数据管理系统紧耦合的问题,提出了应用消息中间件的通用化数据管理系统结构,以消息包传输机制实现了数据流在实时数据库与业务软件间传递解耦合;最后,搭建了面向不同软硬件测试环境的电磁能实时数据管理原型系统,对所提架构进行了单节点和多节点的读写性能测试,并通过业务处理延时指标对比验证了该架构的技术可行性和适配性。

基础地理实体数据库应用管理系统设计与实现

以高效服务城市管理和城市治理为导向,根据自然资源管理和城市信息化发展新需求,结合国家新型基础测绘试点,提出了满足行业应用需求的基础地理实体分类和数据组织模式,设计并建设了基础地理实体数据库及其应用管理系统,解决了地理实体数据汇聚、存储、管理、按需组装等问题,打通了多源异构时空数据管理与应用的壁垒,有力支撑了实景三维西安建设,提升了基础测绘的有效供给能力,为实景三维中国建设提供了借鉴和参考。

倾斜摄影三维模型在不动产登记中的应用研究

随着城市的快速发展和土地利用的立体化,二维不动产登记很难满足准确、直观地管理三维空间信息的需求,而且不动产的登记过程可能复杂而耗时,引发权属冲突。由于3D模型可以定位任何楼层和房屋,因此可以准确确定房产边界、明确所有权、提供准确的登记和认证、提高登记效率。研究开发了一个3D不动产登记数据库,将现有的二维不动产登记系统与现有的二维房地产登记系统连接起来,以验证使用倾斜测量技术进行不动产登记的可行性。

实景三维铁路构建方法研究

为提高铁路工程实景三维技术应用系统化、标准化和多专业、多场景综合应用水平,结合实景三维中国建设整体框架及数字铁路建设需要,对实景三维铁路构建技术进行研究;提出了实景三维铁路构成及地理场景、地理实体、铁路实体等基础数据制作方法;阐述了实景三维铁路的数据库设计、数据库管理及应用服务平台搭建方法,实现多源海量空间数据的统一组织管理、三维场景构建、空间分析应用及在线数据服务。该研究为铁路工程管理提供一体化的三维数字场景,可满足勘察设计、施工建设及运营维护阶段应用需要,提升铁路工程建设管理数字化、智能化水平。

基于ArcGIS平台的不动产登记数据建库研究

为提高不动产登记数据整合效率,实现不动产登记数据的信息化管理,本文从不动产登记数据整合作业流程出发,基于规范要求并详细分析用户需求,借助Oracle数据库、ArcSDE、ArcGIS等工具,构建不动产登记数据库,结合研究区实际概况及需求进行不动产登记整合数据管理系统设计研发,提高研究区不动产登记数据搜集、处理、应用及管理效率;同时对研究区不动产登记过程中普遍存在的问题进行分析总结,针对不同情况提出相应的处理方案。不动产登记整合数据管理系统在研究区内得到了成功应用,提高了不动产登记数据管理应用效率,同时推动了区域内不动产登记信息化建设发展。

数字化钻完井作业在东海油气田应用实践

随着东海油气勘探开发不断深入,钻完井作业量逐年提升,新区域新层系探井评价井增多,高温高压深井、大位移井等高难度井增多,新人新平台占比高,且存在管理力量和人员技能稀释摊薄等问题,给钻完井安全保障和成本管控带来极大的挑战。为应对以上困难挑战,通过整合历史数据与现场动态数据,建立钻完井数据库,利用各类传感装置,实时监测跟踪现场作业,模拟计算井下作业状况,对潜在风险进行预警,利用联井对比优选最佳工艺参数指导现场作业,形成闭环,持续改进,保障现场作业安全,提升现场作业效率,构建起东海钻完井作业数字化作业雏形。