Active Database Management Systems Research Articles

Enhancing distribution generator impact mitigation using an adaptive protection scheme based on modified pelican optimization algorithm and active database management system

AbstractThis paper addresses the challenge of protecting electrical networks in the presence of distribution generators (DGs). The use of DGs affects fault currents, leading to miscoordination between protection relays and causing constraints on network reliability. To tackle this issue, the authors propose an adaptive protection scheme (APS) based on a modified pelican optimization algorithm (MPOA) and active database management system (ADBMS). The APS coordinates directional overcurrent relays and distance relays, while the MPOA simulates a pelican mating strategy and includes a modified internal equation. The proposed APS is further upgraded with ADBMS to save system resources by storing relay settings in the database and calling them when the state of DGs changes without running optimization algorithms. The effectiveness of the proposed APS is validated on the Institute of Electrical and Electronics Engineers (IEEE) eight‐bus test system and the IEEE 14‐bus distribution network. Results indicate that the APS can effectively protect electrical networks in the presence of DGs, while the ADBMS upgrade saves system resources.

Specifying active databases as non-Markovian theories of actions

Over the last 15 years, database management systems (DBMSs) have been enhanced by the addition of rule-based programming to obtain active DBMSs. One of the greatest challenges in this area is to formally account for all the aspects of active behavior using a uniform formalism. In this paper, we formalize active relational databases within the framework of the situation calculus by uniformly accounting for them using theories embodying non-Markovian control in the situation calculus. We call these theories active relational theories and use them to capture the dynamics of active databases. Transaction processing and rule execution is modelled as a theorem proving task using active relational theories as background axioms. We show that the major components of an ADBMS, namely the rule sets and the execution models, may be given a clear semantics using active relational theories. More precisely: we represent the rule set as a program written in a suitable version of the situation calculus based language ConGolog; then we extend an existing situation calculus based framework for modelling advanced transaction models to one for modelling the execution models of active behaviors.

A Practical System to Manage and Control Digital Media

Copyright infringement of intellectual properties has become an increasingly significant problem with the advent of the Internet and the utilization of Internet based information systems that allow users to disseminate files quickly and anonymously. Specifically, we are concerned with the ability to retain control of audio, video, and picture files stored within a database and commonly accessed by numerous individuals. This paper presents a novel approach to the manipulation and management of binary large objects within an active relational database management system through the application of digital watermarking algorithms and Java programming modules. We describe the design and implementation decisions and account our experience of realizing the Active Watermarking System using Oracle DBMS 10g, Oracle JDeveloper 10g, Java, and application-dependent digital watermarking algorithms, which serves as a guide for future similar endeavors.

A Multimodal Biometric System Implemented within an Active Database Management System

Active databases have been used in many different fields to accomplish many different tasks. One of the main problems today that still have not been solved is authorization. In some situations it is enough that user knows e.g. password, in other situations it is enough that user posses e.g. a smart card, but, there are also situations where user’s unique physical or psychological characteristics need to be measured. In this paper we are going to put accent on this third possibility. We will show how the concept of complex events presented in the active database theory could be used in order to build a multimodal biometric system. Especially, we will explore the paradigm of active rules and complex events, and apply them in order to implement a multimodal biometric system.

Performance analysis of long-lived cooperative transactions in active DBMS

Active database management systems (ADBMS) are used in different application domains and especially for cooperative and long duration activity management. This paper deals with performance analysis of long-lived cooperative transaction processing in an ADBMS. We first briefly discuss NP-QuadLock – a concurrency control scheme for cooperative and long durational transactions in ADBMS. A restricted version of NP-QuadLock named 2L-QuadLock has been used for simulation. We have modeled such an ADBMS supporting 2L-QuadLock scheme by a queuing model. The failure of the transactions running in such systems has been modeled by a failure recovery model. We have simulated this model for a transaction processing system serving long-lived and cooperative transactions. We also discuss some important emerging application scenarios, where the proposed cooperative complex transaction mechanism can be used (e.g. 3G-service environment, ubiquitous computing environment, feature composition in intelligent network environment, multi-site and multi-domain web-services). An important objective of our work is to analyze quantitatively (a) the performance penalty on the system due to the partial abort, the number of locks held by a transaction, the number of states of the transactions, and (b) the gain in the performance of the system with the cooperation semantics proposed in 2L-QuadLock concurrency control mechanism. We have analyzed the effect of various parameters such as partial abort rate, cooperation rate, number of locks held by a transaction, multiprogramming level, on the performance metrics such as average service time, average saga length and the degree of compensation. Later, we characterize the application scenarios based on some important simulation parameters, and discuss the application performance needs for each of the application scenarios. The required performance parameters that need to be used for these application scenarios and the corresponding performance results using 2L-QuadLock are also discussed.

AUTOMATIC ENFORCEMENT OF BUSINESS RULES AS ADBMS TRIGGERS FROM CONCEPTUAL GRAPHS MODEL

The business rules approach to business information systems development has already gained a lot of attention from both research communities and commercial organizations. In this paper we survey the current situation and point out the lack of standards in business rules technologies. We elaborate on our approach to business rules modeling by conceptual graphs and enforcement tasks which is presented in our earlier publications, now focusing on trigger generation component, which employs active database management systems as the rules enforcement technology, also allowing the possibility of rules sharing or exchange through the business rules repository in XML format.

Data Protection Using Watermarking in E-Business

In the past decade, the business community has embraced the capabilities of the Internet for a multitude of services that involve access to data and information. Of particular concern to these businesses have been the protection and authentication of digital data as it is distributed electronically. This paper proposes a novel approach that combines the reactive rule-based scheme of an active database management system (ADBMS) with the technology of digital watermarking to automatically protect digital data. The ADMBS technology facilitates the establishment of Event-Condition-Action (ECA) rules that define the actions to be triggered by events under certain conditions. These actions consist of the generation of unique watermarks and the tagging of digital data with unique signatures. Watermarking is a technology that embeds, within the digital data’s context, information identifying its owner and/or creator. The integration of these two technologies is a powerful mechanism for protecting digital data in a consistent and formal manner with applications in e-business in establishing and authenticating the ownership of images, audio, video, and other digital materials.

SAMOS in hindsight: experiences in building an active object-oriented DBMS

Active object-oriented database management systems incorporate object-oriented database technology and active mechanisms such as event-condition-action rules (ECA-rules). SAMOS has been among the first representatives of this class of systems. During the development of SAMOS, numerous then open research questions have been addressed. In this paper, we present a “historical” perspective of the SAMOS project and report on lessons and experiences we have gained in the project. We identify requirements, present feasible solutions, and report on experiences we have drawn from this project. In particular, we describe the rule model of SAMOS, which represents a smooth integration of ECA-rules into an object-oriented data model. We also discuss the implementation and architecture of the SAMOS prototype on top of a passive object-oriented database management system (OODBMS). Furthermore, we report on performance and usability issues. In order to analyze performance, we have developed a benchmark; we discuss the experiences (and improvements) we have made by running the benchmark on SAMOS and by comparing the results to those obtained for other systems. Usability issues have been investigated with respect to tool support for designing SAMOS applications and analyzing rule systems. Finally, we discuss our experiences in implementing SAMOS and the conclusions we have drawn for the implementation of other types of event-based persistent systems as well as a development method for active systems in general.

OBJECTIVE: a benchmark for object-oriented active database systems

Although much work in the area of Active Database Management Systems (ADBMSs) has been done, it is not yet clear how the performance of an active DBMS can be evaluated systematically. In this paper, we describe the OBJECTIVE Benchmark for object-oriented ADBMSs, and present experimental results from its implementation in an active database system prototype. OBJECTIVE can be used to identify performance bottlenecks and active functionalities of an ADBMS, and to compare the performance of multiple ADBMSs.

Performance evaluation of object-oriented active database systems using the BEAST benchmark

This paper uses the BEAST benchmark to present the first serious performance study of object-oriented active database management systems (ADBMS). BEAST stresses the performance-critical components of active systems: event detection, event composition, rule retrieval, and rule firing. Method invocation events and transactional events are taken into account. Four systems, namely ACOOD, NAOS, Ode, and SAMOS, have been tested with the benchmark tests of BEAST. The performance measurements demonstrate achievements in the area of active database technology, but also indicate tradeoffs (e.g. between performance and functionality). Finally, the benchmark identifies optimizations and provides hints to ADBMS desigers about producing systems with adequate performance and functionality --- as well as some open issues.

A technique for modeling applications in active object oriented database management systems

Active Database Management Systems (ADBMS) are finding increasing application in diverse domains, especially in different kinds of control applications and long-duration activity management. An ADBMS gives users the facility to define dynamic semantics of the application as a part of the database. Recently Active Object Oriented Database Management Systems (AODBMS) are also finding increasing popularity because of its rich modeling power. In this paper, a modeling scheme for AODBMS applications has been proposed. The novel feature of the proposed approach is that it allows modeling in three orthogonal dimensions, viz. object dimension, event dimension and transaction dimension. The application semantics is viewed as an interrelationship among the modeled components in each of these dimensions. An execution model for AODBMS transactions which are long duration and cooperative in nature has also been presented.

EXACT: an extensible approach to active object-oriented databases

Active database management systems (DBMSs) are a fast-growing area of research, mainly due to the large number of applications which can benefit from this active dimension. These applications are far from being homogeneous, requiring different kinds of functionalities. However, most of the active DBMSs described in the literature only provide a fixed, hard-wired execution model to support the active dimension. In object-oriented DBMSs, event-condition-action rules have been propo sed for providing active behaviour. This paper presents EXACT, a rule manager for object-oriented DBMSs which provides a variety of options from which the designer can choose the one that best fits the semantics of the concept to be supported by rules. Due to the difficulty of foreseeing future requirements, special attention has been paid to making rule management easily extensible, so that the user can tailor it to suit specific applications. This has been borne out by an implementation in ADAM, an object -oriented DBMS. An example is shown of how the default mechanism can be easily extended to support new requirements.

Graph-based rules and transactions for parallel and active database systems

Active database management systems are becoming increasingly popular because of their relevance to several advanced and complex database applications. The need for user-defined execution orders (or control structures) for rules is well recognized by researchers of active database management systems. Priority-based approaches (e.g., numeric priorities) have been used to specify a desired control structure among rules. However, due to the fact that fixed priorities are assigned to rules, independent of different contexts in which they may be triggered, the existing approaches are not able to allow rules to be executed following different control structures when they are triggered by different events. More flexible and expressive control mechanisms are often needed for rules in advanced database applications such as CAD/CAM, CASE, CIM and flexible manufacturing systems. Since rules in database environments are executed in a transaction framework, an expressive transaction model is needed to model complex control structures among rulesuniformly. In this work, we separate the event part from the condition-action parts of a rule and associate it with a rule graph which represents a set of rules (actually a set of condition-action pairs) sharing the same control structure. Different rule graphs can be defined under different event specifications thereby enabling a set of rules to follow different control structures when triggered by different events. We also use an expressive graph-based transaction model to incorporate the control structures of rule graphs uniformly in a transaction framework. The proposed rule and transaction modeling and execution techniques have been implemented and verified on a shared-nothing multiprocessor computer nCUBE2. In this paper, we also describe the client-server architecture and different parallel transaction and rule execution techniques that have been used for the implementation. Finally, we analyze the speedup and scaleup of the implemented system.

The active database management system manifesto

Active database systems have been a hot research topic for quite some years now. However, while “active functionality” has been claimed for many systems, and notions such as “active objects” or “events” are used in many research areas (even beyond database technology), it is not yet clear which functionality a database management system must support in order to be legitimately considered as an active system. In this paper, we attempt to clarify the notion of “active database management system” as well as the functionality it has to support. We thereby distinguish mandatory features that are needed to qualify as an active database system, and desired features which are nice to have. Finally, we perform a classification of applications of active database systems and identify the requirements for an active database management system in order to be applicable in these application areas.

Heraclitus

Traditional database systems provide a user with the ability to query and manipulate one database state, namely the current database state. However, in several emerging applications, the ability to analyze “what-if” scenarios in order to reason about the impact of an update (before committing that update) is of paramount importance. Example applications include hypothetical database access, active database management systems, and version management, to name a few. The central thesis of the Heraclitus paradigm is to provide flexible support for applications such as these by elevating deltas , which represent updates proposed against the current database state, to be first-class citizens. Heraclitus[Alg,C] is a database programming language that extends C to incorporate the relational algebra and deltas. Operators are provided that enable the programmer to explicitly construct, combine, and access deltas. Most interesting is the when operator, that supports hypothetical access to a delta: the expression E when σ yields the value that side effect free expression E would have if the value of delta expression σ were applied to the current database state. This article presents a broad overview of the philosophy underlying the Heraclitus paradigm, and describes the design and prototype implementation of Heraclitus[Alg, C]. A model-independent formalism for the Heraclitus paradigm is also presented. To illustrate the utility of Heraclitus, the article presents an in-depth discussion of how Heraclitus[Alg, C] can be used to specify, and thereby implement, a wide range of execution models for rule application in active databases; this includes both prominent execution models presented in the literature, and more recent “customized” execution models with novel features.

Business rules in systems analysis: A meta-model and repository system

Commonly used methodologies for systems analysis are data- or function-oriented. These methods are sufficient for information systems which will be implemented using passive database management systems (DBMS). In the last years, several research prototypes of active DBMS and active mechanisms for commercially available DBMS have been developed. To fully use the potential of these rules, a systems analysis methodology with rules as central construct seems to be necessary. This paper defines and structures business rules as a main component of systems analysis and presents a meta-model for business rules; furthermore, the implementation of a repository system based on the meta-model is described.

The architecture of an active database management system

The HiPAC project is investigating active, time-constrained database management. An active DBMS is one which automatically executes specified actions when specified conditions arise. HiPAC has proposed Event-Condition-Action (ECA) rules as a formalism for active database capabilities. We have also developed an execution model that specifies how these rules are processed in the context of database transactions. The additional functionality provided by ECA rules makes new demands on the design of an active DBMS. In this paper we propose an architecture for an active DBMS that supports ECA rules. This architecture provides new forms of interaction, in support of ECA rules, between application programs and the DBMS. This leads to a new paradigm for constructing database applications.

Events Specification In Active DatabaseManagement System

Active Databases Management System have been objective of countless researches in the last years. Its active functionalities, as well as the concept of active objects or events are used in several application areas, not only in technology of databases. However, there is not a clearly defined notion distinguishing systems considered actives of the non actives. However, certain essential characteristics are requested for the elaboration of these active functionalities, as EGA rules definition, events specification, production rules, and others. The present paper goals to give a generic view of one of those mentioned characteristics that I consider to be one of the most fundamental topics for the elaboration of active systems, that is the events specification. Starting from a solid and concise specification of the concerning events to a certain application, the elaboration of a efficient rules execution model for an active database management system is possible. This way, it will be given a general vision of the EGA rules, the event concept, its relationships, its types and classifications, and the pertinent operators to the events algebra. The establishment's necessity of the conditions that leads the events specification will be exposed, the definition of the executed actions when of the occurrence of events and the conditions validation, approached inside of the concept of the production rules. Transactions on Information and Communications Technologies vol 19 © 1998 WIT Press, www.witpress.com, ISSN 1743-3517