Related Research Grants

1. Prototyping of Distributed Real-time Database Systems

(Period: Nov 95 to Oct 97)

(CityU Strategic Grant, amount: HK$314,380)

(Completed and the comment from the Research Committee of CityU on the result of the project was excellent)

The project on prototyping of distributed real-time database systems was started in 1994 and was completed in 1997. A prototype of distributed real-time database system was developed which is for the application of programmed stock trading. In the prototype, different priorities can be assigned to transactions based on their deadlines and criticality. Triggered transactions are supported to react to critical events occurred in the external environment. The scheduling of transactions is then according to their priorities so that a timely response to the changing situation in the stock market can be provided.

2. Maintaining Data Consistency in Mobile Computing

(Period: Jul 96 to Jun 98)

(CityU Strategic Grant, amount: HK$388,141)

The objective of the project is to investigate and design efficient algorithms to maintain data consistency for mobile computing systems. In the last year, we have reviewed the state of art in the area and developed a simulation model. Different important issues in maintaining data consistency for mobile computing systems have been identified such as low bandwidth in wireless communication, high volume of data for transmission, frequent failures of network and mobility of mobile clients.

A simulation model for mobile computing systems has developed. The issues related with maintaining database consistency in mobile computing systems have been examined. Different data management protocols, such as for data broadcast and consistency management have been designed.

3. Maintaining Temporal Consistency in Real-Time active Databases

(Period: Jul 98 to Jul 2000)

(Hong Kong UGC Grant, amount: HK$380,000)

The research on real-time database systems has received a lot of interests in recent years. Real-time database systems (RTDBS) are generally defined as the database systems where transactions have explicit deadlines on their completion times. Missing the deadlines may seriously affect the usefulness of completing the transactions and, sometimes, catastrophic consequences may be resulted. Some common applications of RTDBS are international stock market systems, network management systems, air traffic control systems and navigation systems. One of the major characteristics of this kind of applications is that they have to react to the changing external environment in a real-time manner.

In recent years, there is a strong move toward integrating RTDBS with active database systems with an attempt to provide a better solution to their potential applications, the time-critical applications which have to handle transactions and data in a real-time manner. The new systems are called Real-time Active Database Systems (RTADBS). It is expected that by introducing the active mechanisms into RTDBS, the time-critical database applications can be supported more efficiently and the systems can provide a better response to the critical events occurred in the external environment.

Due to the high complexity of RTADBS, a lot of design issues are still not clear and under study. As the typical applications of RTADBS require the management of large amount of data with temporal consistency requirements and to react to the critical events occurred in the external environment, the database systems need to support a set of rules for identify necessary actions and efficient triggering mechanism. The objective of this proposed project is to investigate and develop new and advanced technologies for maintaining temporal consistency of data and at the same time to support efficient transaction processing to response to the changing external environment.

4. Scheduling transactions in Distributed Real-time Active Database

(Period: Oct 98 to Sep 2000)

CityU Strategic Grant, amount: HK$176,000)

5. Scalable Strategies for Maintaining Cache Coherency for Mobile Web-Based Systems

(Period: Sept 2000 to August 2002)

(CityU Strategic Grant, amount: HK$225,400)

 6. Efficient Concurrency Control Protocols for Transactions in Mobile Real-time Database Systems

(Period: Oct 2000 to Sept 2002)

(Hong Kong UGC Grant, amount: HK$437,817)

7. Real-time Information Dissemination in Mobile Environment

(Period: Oct 99 to Sept 2001)

(Hong Kong UGC Grant, amount: $405,000)

8. Cache Maintenance Strategies for Mobile Web-based Systems

(Period: April 2001 to March 2003)

(CityU Strategic Grant, amount: $250,000)

9. Monitoring of Real-time Data of Moving Objects in Mobile Computing Systems

   (Period: May 2001 to April 2003)

  (CityU Strategic Grant, amount: $239,400)