Kwang Woo Nam

Indexing for Efficient Managing Current and Past Trajectory of Moving Object

For efficiently managing of moving object trajectories, several indexing methods have been proposed such as 3DR-tree, STR-tree, TB-tree. These indexing methods have been focused on only improving query performance. However, due to property of continuously changing its position, moving objects generate massive data and have to update its information frequently. Therefore, in this paper, we proposed an indexing method for managing current and past trajectories of moving objects efficiently. The proposed method employed auxiliary cache for efficient updating performance. We also proposed the method which can be reduced the index size by removing redundant information for expression of moving object trajectory. We showed that the proposed method has not only the better performance for update and much smaller size of index size, but also almost same performance for the query compared to previous indexing method.

Design and Implementation of Event Notification System for Location- and RFID-based Logistics Environment

Advanced wireless network and sensor technologies are capable of collecting information such as temperature, humidity, weight, and location about objects at real time in logistics area. Besides, users want to be notified of contextual information about interest of objects whenever they want it and wherever they want it. To satisfy these requirements, applications should collect and analyze contextual information at real time, and must support a service that can notify it to wanted users. Event-based service is one of the way to satisfy these requirement of users. In this paper, we design an event notification system focused on location- and RFID-based logistics area. To do this, we present XML-based event expression model, ECA-based profile definition model, and an algorithm that has high scalability by distinguishing event filtering in two steps. Based on these designs, our implemented system can apply to not only logistics area but also intelligent traffic control system based on RFID or GPS devices.

Developing a Main Memory Moving Objects DBMS for High-Performance Location-Based Services

This paper proposes a moving objects data model, query language, main memory database system for location-based service. Location-based services require GIS databases system to represent moving objects and to support querying on the motion properties of objects. For example, fleet management applications may require storage of information about moving vehicles. Also, advanced CRM applications may require to store and query the trajectories of mobile phone users. But, modeling consistent information about the location of continuously moving objects and processing motion-specific queries is challenging problem. We formally define a data model and data types for moving objects that includes complex evolving spatial structure and indeterminacy, and then describe the system implementation.