/ Subhash Bhalla / Associate Professor
Existing research activity in the area of database systems aims to capture a wide variety of applications into the fold of DBMS (Database Management System) technology. This is due to improved understanding of information extracted from databases by the usage of advanced DBMS techniques. The DBMSs currently use visual representations within new interfaces to manage large volumes of data, and also to manage data that may have complex features associated with its structure. In addition to complexity in features, such as multiple attributed data, wave-forms and multi-dimensional orientation, many new types of raw data are emerging that need to be captured by DBMSs for the purpose of information extraction. Among these, the image data and video image data are two important forms of data and many research efforts are being made to make suitable DBMS architectures for image and multimedia databases.
In order to provide flexibility in terms of data representation, the databases need the support of powerful data-modeling techniques. Most of the advances in techniques concentrate on capturing more meaning within data that is made resident on a computer system. Within this framework, a number of researchers are actively developing improved data management strategies.
On the implementation side, existing database systems consist of many layers of software within a DBMS ( Database Management System). These layers are mostly independent of each other. The layers are prepared to meet a specific function, such as parallel accesses or transaction commit. These impose many delays and processing constraints. In addition to this fact, at many times the software architecture is an old design, because software systems are slower to develop as compared to hardware design changes. Therefore, the DBMS architectures are based on inefficient design techniques, in many cases. Due to these two factors, many design bottlenecks exist that lead to lower level of performance of database systems, especially when dealing with many new database applications, concerning with industrial applications.
A new set of performance factors are important in new time-critical applications such as in Mobile databases for electronic commerce, and Multimedia applications using Real-time databases, in process and manufacturing industries. Thus, our aim is to reduce the worst time estimates and increase dependability of computation within a specified unit of time. Many research efforts are being made to develop capabilities within the next generation software systems that need to support time-critical transactions. This provides a challenging area for study in many domains of activity. These include :
A high level of reliability of operations is also neccesary within these systems to ensure quick response in case of failure. Thus, the activity of performance evaluation of transaction processing systems is an important area that provides improved understanding of systems. This facilitates improved integration and refinement in technique. The Database Systems Laboratory has research activity concentrating on data modeling as well as transaction processing activity. A brief outline of the ongoing projects is given below.
Information Processing Systems of future will be a combination of integrated components. There will be components for intelligent problem solving, or decision making, components for specialized data processing (e.g., image enhancers), and components for shared information management. The applications will utilize a shared base of information. The examples of some of the application domains are business automation, industrial automation, computer-aided design and manufacture, and cartography. Under the "Data Modeling for Complex Objects" the new approaches for representing such objects are being explored. The studies are currently focused on the Object-Relational data model.
One of the new challenging area of interest in transaction management is that of Real-time database systems in which transactions have time constraint. Within the new environment, the database management system must support a mix of ordinary as well as real-time transactions. The transaction support must also be highly reliable and fast. Traditional approaches to transaction management introduce elements of unpredictable delays during transaction processing. Thus, making these not suitable for adoption in new application environments. The techniques for time-critical transactions are applicable to Mobile databases and multimedia databases.
Research activity in the area of process modelling and parallel algorithms for data mining and knowledge discovery is in progress.
Refereed Journal Papers
With frequent increase in processor speeds, new approaches that can take advantages of local processing, tend to become viable. This is due to a simultaneous increase in contrast between delays due to local processing and communication delays. We propose a new approach with changes in data and information structures. In addition to local processing, we also propose an efficient synchronization algorithm for exchange of precedence in case of a conflict, and for efficient time-stamp management incurring, a minimal global synchronization overhead.
Refereed Proceeding Papers
In a real-time database system, an application supports a mix of transactions. These include the real-time transactions that require completion by a given deadline. Existing concurrency control procedures introduce excessive delays due to non-availability of data resources. In this study, we ignore the delays incurred by ordinary transactions, in order to achieve a non-interference mode of execution (near parallel) for the time-critical transactions. In this report, a data allocation model has been studied, that is based on the use of two-phase locking for controlling access to data resources.
A "Hyperdictionary" is essentially a relational and deductive database containing information about a set of languages, together with an open-ended set of access and display methods for that information. Working towards the creation of a Japanese-English hyperdictionary with many and varied applications and functionalities, we are close to completing a beta-testable implementation of a web-based high-level multi-purpose tool for Japanese information processing. One of the special features of this implementation is the ability to use any character or graphical element X as an index to find all characters Y which graphically contain X.