I am currently working on Spatio-Temporal databases with Dr. Shashi K. Gadia. Current research focuses on the implementation of a spatio-temporal database whose data model is the parametric data model. The parametric data model handles heterogeneous dimensional data seamlessly, leading to a reduction of the query complexity. I am designing and implementing the parametric structured query language (ParaSQL). The ParaSQL is an SQL-style query language, but it is different from them because it has a mechanism to handle multiple dimensions. In order to implement the database, many issues occur, such as parsing, expression trees, optimization, storage, buffer management and so on. In addition to my main research work, my research interests can be listed as follows:

[Temporal Databases]

Conventional database systems are only capable of storing and querying the current perception of reality and relationship among objects, such database systems exclude old data values when updating them. Temporal databases provide the capability to store and query complete object histories.

There are many different types of temporal data models and they have their own merits in their specific application areas. According to Jansen, there are more than 2000 research papers on temporal databases. The data models can be categorized based on three criteria, such as domain representation, domain visibility, and time stamping schemes.

[XML Databases]

XML is an emerging technology and used everywhere in applications. XML and Databases seem to be an odd couple at first glance because they represent two different concepts driven by two different communities with different expectations and requirements. In spite of the differences, many researchers have utilized XML technology in database research. Because of XML, a new database generation is emerging. The greatest challenge in XML databases is a storage technology. Because XML documents are semi-structured data, it is not suitable to store them in predefined formats.

[Query Languages in Multi-Dimensional Databases]

The primary purpose of database query languages is to retrieve data from databases. Those query languages should reflect natural language¡¯s aspects in order to reduce query complexities from the user¡¯s viewpoint. Multi-dimensional databases such as Spatio-Temporal Databases, should handle multiple dimensions that are heterogeneous. Since time and space dimensions are heterogeneous, query languages should provide a different handling mechanism for those dimensions. However, they can be handled in the same manner at the abstract level. Multiple dimensions are seamlessly expressed in natural languages like English. For example, ¡°Retrieve all days when temperature was below 60 degrees in Ames.¡± The query contains space and time dimensional information. However, it is seamlessly expressed. Therefore, it is important that query languages are as similar as natural language so that users express themselves without much effort.

[Natural Language Processing]

The natural language processing is to understand human and process languages. It can be used in many areas, such as information retrieval systems and automatic reservation systems. Since this research area is too broad, most researchers tend to restrict domain of applications. I spent two and half years in Natural Language Processing Laboratory in the Department of Computer Engineering at Chungbuk National University. While I was staying there, I designed and implemented a Korean language parser. My final purpose of this research is to transform databases query languages into natural languages.