Real-time Database Management System Research Articles

Analysis on NSAW Reminder Based on Big Data Technology

NSAWS is an intelligent and real-time large database management system. By analyzing the user identity data and access rights contained in the collected information, the NSAWS finds out the potential risks and issues an alarm notice in a timely manner. This paper mainly studies how to strengthen the prevention of network attacks in BD environment from the following aspects. This paper first introduces the common technology on the Internet in our country and its application status; secondly, it expounds the architecture, deployment mode and operation mode of the large database system based on the basic security facilities such as cloud computing platform and firewall. Then the traditional NSAWS is analyzed and the simulation platform is tested. The results show that the platform has high accuracy and stability in alerting network security hazards and can effectively protect network security.

Improving the quality of service of real-time database systems through a semantics-based scheduling strategy

A real-time database management system (RTDBMS) aims to manage applications with a large number of data being accessed by update and user transactions having to meet some time constraints. We are interested in improving the quality of service (QoS) in RTDBMSs by optimising the execution of transactions to improve meeting their deadlines. A new scheduling strategy is developed and evaluated into a QoS management architecture called feedback control scheduling (FCS) proposed for RTDBMSs. The proposed strategy is based on the new advanced earliest deadline first based on transactions aggregation and data semantic links (AEDF-TAL-DSL) protocol we developed. It introduces new parameters relating to the aggregation links (defined according to the type of operations composing the transactions and the data they access) existing between transactions as well as the semantic links appearing between the users' queries. We also show the contributions provided by our approach through simulation results.

Research on Real-Time Database Recovery Method of Smart Grid System Based on IEC61970 Standard

Real-time database management system plays an important role in power grid system. With the increasing development of smart grid, the problem of data integrity security in real-time database has attracted more and more attention. Research on real-time database recovery Method of Smart Grid system is based on IEC61970 standard using RFID algorithm. After the data integrity is destroyed, it takes only a rollback malicious transaction, without having to roll back all transactions, the transaction conflict caused by the transaction revocation can be avoided, that can improve the survivability of real-time databases, protect the integrity of the real-time database of smart grids, and improve power grid dispatching system. Therefore, real-time database recovery Method plays an important role in power grid dispatching system.

QoS Aware Replica Control Strategies for Distributed Real Time Database Management System

In distributed real time database management system (DRT-DBMS), QoS aware replication control strategy is necessary to ensure availability and to improve the system performance. Since user request and need of data is dynamic in nature, it requires an approach which addresses the problem of data distribution and also resolves them in DRT-DBMS. A large quantity of data file is produced so we need a dynamic replication approach through which we can reduce the data access time. In order to replicate it, at the nearest site, replica placement and replacement algorithms are required to be evaluated. This paper presents a heuristic approach Greedy-Cover Firefly algorithm in which replica is placed dynamically based on QoS requirement and replaced with the optimal adaptive replica replacement algorithm for each data object. The replication cost required for copying data object to each set of a node is calculated to select the optimal node. Here, the replication decision is taken on the basis of access history of data on multiple sites. Due to the limited storage capacity of each node, the value of each file is calculated, and the file with the smallest value is removed to replace other files. A detailed simulation shows that the proposed algorithms can greatly improve the system performance to reduce the system resources consumed with respect to time and QoS requirement.

Model Driven Engineering for Quality of Service Management

Real-time applications managing a large number of real-time data require the use of Real-time Database Management Systems (RTDBMS) to meet temporal constraints of both real-time data and transactions. However, a RTDBMS has a dynamic workload and may be frequently overloaded since the arrival times and workloads of user transactions are unpredictable. Therefore, Quality of Service management solutions have been proposed to guarantee the stability of RTDBMS even during unpredictable overload periods. While effective, the design and reuse of these solutions is challenging because they are not formally modeled and there is no tool neither a methodology that helps us design such solutions. To address these issues, the authors propose a design framework based on the Model-Driven Engineering approach providing a modeling architecture, a strategic methodology and a software tool to support modeling and reusing such solutions. The framework is implemented and tested for a real Qos management solution.

Dynamic Real Time Distributed Sensor Network Based Database Management System Using XML, JAVA and PHP Technologies

Wireless Sensor Network (WSN) is well known for distributed real time systems for various applications. In order to handle the increasing functionality and complexity of high resolution spatio-temporal sensory database, there is a strong need for a system/tool to analyse real time data associated with distributed sensor network systems. There are a few package/systems available to maintain the near real time database system/management, which are expensive and requires expertise. Hence, there is a need for a cost effective and easy to use dynamic real-time data repository system to provide real time data (raw as well as usable units) in a structured format. In the present study, a distributed sensor network system, with Agrisens (AS) and FieldServer (FS) as well as FS-based Flux Tower and FieldTwitter, is used, which consists of network of sensors and field images to observe/collect the real time weather, crop and environmental parameters for precision agriculture. The real time FieldServer-based spatio-temporal high resolution dynamic sensory data was converted into Dynamic Real-Time Database Management System (DRTDBMS) in a structured format for both raw and converted (with usable units) data. A web interface has been developed to access the DRTDBMS and exclusive domain has been created with the help of open/free Information and Communication Technology (ICT) tools in Extendable Markup Language (XML) using (Hypertext preprocessor) PHP algorithms and with eXtensible Hyper Text Markup Language (XHTML) self-scripting. The proposed DRTDBMS prototype, called GeoSense DRTDBMS, which is a part of the ongoing IndoJapan initiative ‘ICT and Sensor Network based Decision Support Systems in Agriculture and Environment Assessment’, will be integrated with GeoSense cloud server to provide database (dynamic real-time weather/soil/crop and environmental parameters) and modeling services (crop water requirement and simulated rice yield modeling). GeoSense-cloud server has been developed with Opera-Unite for file sharing, web server (with cost effective web server tools Windows Apache MySQL PHP-WAMP and X -any operating systems Apache MySQL PHP and Perl –XAMPP), file upload, and web proxy functionalities. Currently, the GeoSense DRTDBMS is useful to the rural farming community for ubiquitous decision making in precision agriculture aspects. In future, this DRTDBMS system could be used in climate/environmental systems to understand the micro-climatic variations in real-time mode.

Data management for component-based embedded real-time systems: The database proxy approach

We introduce the concept of database proxies intended to mitigate the gap between two disjoint productivity-enhancing techniques: component based software engineering (CBSE) and real-time database management systems (RTDBMS). The two techniques promote opposing design goals and their coexistence is neither obvious nor intuitive. CBSE promotes encapsulation and decoupling of component internals from the component environment, whilst an RTDBMS provide mechanisms for efficient and predictable global data sharing. A component with direct access to an RTDBMS is dependent on that specific RTDBMS and may not be useable in an alternative environment. For components to remain encapsulated and reusable, database proxies decouple components from an underlying database residing in the component framework, while providing temporally predictable access to data maintained in a database. Our approach provide access to features such as extensive data modeling tools, predictable access to hard real-time data, dynamic access to soft real-time data using standardized queries and controlled data sharing; thus allowing developers to employ the full potential of both CBSE and an RTDBMS. Our approach primarily targets embedded systems with a subset of functionality with real-time requirements. The implementation results show that the benefits of using proxies do not come at the expense of significant run-time overheads or less accurate timing predictions.

An improved 2PL-HP based concurrency control algorithm in real time database

In the real time database management systems the mechanism of concurrency control 2PL-high priority, by applying a sacrificing approach of the low-priority transaction during the competition with high priority transaction, not only waste the resources of the system but also decrease the system efficiency due to the increase of the transaction failure because of miss deadline. The survey is focusing on the weak points of this mechanism and presenting a new approach that by omitting the unnecessary restarts greatly improve the efficiency of the system. We also present a new approach for determining the transaction's priority to provide the possibility of more successful transaction. This approach will be more prominent especially when there is more competition among the transactions for locking the resources of the system. By modeling the behavior system in Markov model, this increase in efficiency of the system comparing to the 2PL-HP mechanism has been improved. Key words: Real time databases, concurrency control, transaction priority, performance evaluation.

Modeling selected real-time database concurrency control protocols in Uppaal

Real-time database management systems (RTDBMS) are recently subject of an intensive research. Model checking algorithms and verification tools are of great concern as well. In this paper, we show some possibilities of using a verification tool Uppaal on some variants of pessimistic and optimistic concurrency control protocols used in real-time database management systems. We present some possible models of such protocols expressed as nets of timed automata, which are a modeling language of Uppaal.

Evolving a model of transaction management with embedded concurrency control for mobile database systems

Transactions within a mobile database management system face many restrictions. These cannot afford unlimited delays or participate in multiple retry attempts for execution. The proposed embedded concurrency control (ECC) techniques provide support on three counts, namely—to enhance concurrency, to overcome problems due to heterogeneity, and to allocate priority to transactions that originate from mobile hosts. These proposed ECC techniques can be used to enhance the server capabilities within a mobile database management system. Adoption of the techniques can be beneficial in general, and for other special cases of transaction management in distributed real-time database management systems. The proposed model can be applied to other similar problems related to synchronization, such as the generation of a backup copy of an operational database system.

Software architecture for a firm real-time database system

Abstract An actual development of a real-time database management system (RT-DBMS) must confront many new and practical problems which have been often ignored in previous work based on simulation. In addition to transaction scheduling, an RT-DBMS must deal with resource and data contention and enforce timing constraints. This paper discusses how current real-time technology has been applied to architect an RT-DBMS on a real-time microkernel operating system and how the problems have been addressed. We present the current software architecture of our StarBase RT-DBMS and address how it can be extended to support both guaranteed and non-guaranteed transaction processing.

Implementation of a real-time database system

A real-time database system is a database system in which transactions have explicit timing constraints such as deadlines. Apart from satisfying the database consistency constraints, transaction executions must also satisfy these timing constraints. The goal of transaction and query processing in real-time databases is to maximise the number of successful transactions in the system. This paper reports on the design, development and performance evaluation of RT-Genesis, a real-time database management system resulting from modifying an existing commercial DBMS, Genesis. RT-Genesis is a relational database management system that accommodates SQL queries and transactions having time constraints. It features time-cognizant algorithms for scheduling, concurrency control and buffer management. The system has been tested and the performance of the different algorithms compared in isolation as well as in combination with different classes of SQL workloads. In addition, a two-phased approach to transaction execution has also been implemented with the goal of exploiting access invariance to improve predictability. This work demonstrates the feasibility of converting non-real-time DBMSs into real-time DBMSs for firm deadline transactions. Besides reporting on how this was achieved and on the performance of the incorporated algorithms, lessons learned from this experience are also discussed.

Concept for a Real-Time Structured Database Query Language (RT-SQL)

Real-time database management systems have become a hot topic in the research and development community of late (Fort94a, Grah93, WCPP93). In addition there has been a movement in the standards community to examine and develop extensions to existing and proposed query languages to support real-time (Fish94, Fort94, Fort94a, FS94, Gord94).This paper examines the state of research into real-time database management systems in the areas of database structuring, transaction structuring, transaction processing, concurrency control, recovery and real-time transaction scheduling. We then extend the findings and trends of this work into the high level specification of data definition language, data manipulation language and data control language extensions for the standard SQL2 and emerging SQL3 database query languages.

Concept for a real-time structured database query language (RT-SQL)

Real-time database management systems have become a hot topic in the research and development community of late (Fort94a,Grah93,WCPP93). In addition there has been a movement in the standards community to examine and develop extensions to existing and proposed query languages to support real-time (Fish94,Fort94,Fort94a,FS94,Gord94). This paper examines the state of research into real-time database management systems in the areas of database structuring, transaction structuring, transaction processing, concurrency control, recovery and real-time transaction scheduling. We then extend the findings and trends of this work into the high level specification of data definition language, data manipulation language and data control language extensions for the standard SQL2 and emerging SQL3 database query languages.

Development of a real-time database management system for production process-control applications

Computers are becoming more widely used in a large number of the complicated scientific applications such as aerospace and defense systems, nuclear reactor control, and computer integrated manufacturing (CIM) with their ever-increasing performance-price ratio. These applications require not only complex scientific processing/analysis but also real-time processing for their data to control external devices correctly. To support real-time applications, a real-time database system which satisfies the requirements of timing constraints in collecting, updating and retrieving data is needed. This paper describes WatchMan, a real-time database system which supports engineering data required in CIM applications in monitoring and controlling machines in the factory. In order to provide real-time processing features, the real-time database system manages all data as a main memory database. A new storage structure and an access method appropriate for main memory databases have been developed for this purpose. Also, concurrency control and recovery techniques suitable for the real-time processing in the CIM environment have been proposed. In addition, this paper presents solutions to the problems which result from developing the main memory databases under Unix system.