Dae-Soo Cho

The self-relocating index scheme for telematics GIS

The history management of vehicles is important in telematics applications. To process queries for history data, trajectories, we generally use trajectory-preserving index schemes based on the trajectory preservation property. This property means that a leaf node only contains segments belonging to a particular trajectory, regardless of the spatiotemporal locality of segments. The sacrifice of spatiotemporal locality, however, causes the index to increase the dead space of MBBs of non-leaf nodes and the overlap between the MBBs of nodes. Therefore, an index scheme for trajectories shows good performance with trajectory-based queries, but not with coordinate-based queries, such as range queries. We propose a new index scheme that improves the performance of range queries without reducing performance with trajectory-based queries. In the new index scheme using the entry relocation strategy, two entries in different nodes are exchanged to minimize the dead spaces of the MBBs of the corresponding nodes.

Optimal Page Ordering for Region Queries in Static Spatial Databases

Page ordering is to define the order of pages in one-dimensional storage for storing two-dimensional spatial data to reduce the number of disk seeks. Previous works relating to page ordering have only used the space filling curves, especially the Hilbert curves. Page ordering based on the space filling curves does not take into account the uneven distribution of spatial data and the types of spatial queries. In this paper, we develop a cost model to be used for defining the problem of page ordering based on performance measurement and then find out the optimal page ordering based on the cost model for processing region queries in static databases. The experimental results show that the newly proposed ordering method can achieve considerable improvement over the previous ordering methods.

Design of an Inventory Management System for Refrigerated Warehouses on Mobile Environments

It is an important job to manage the storing/unstoring state or the inventory state of logistics efficiently and accurately at the inventory management system for refrigerated warehouses. Since the inventory management system is running on the legacy system which is the closed client–server system, the maintenance of the system is costly and labor-intensive. Also, the inventory management system does not provide any services to the cosigners and the consigners should use phones or faxes to place or obtain orders. Thus, the business process becomes inefficient and inaccurate because the old-fashioned management system requires human involvement. In this paper, we design and implement the mobile framework to provide various services for a consigner with a mobile device. If a consigner requests the job or the information of logistics with a mobile device, the mobile framework connects to the legacy system and processes the job or retrieves the related data from the legacy system. Since the consigner is able to check the inventory state and handles the orders directly without any human involvement, the management for the refrigerated warehouse becomes more accurate and efficient.

Information Reminder System Based on Word Registered by User

According to the Hermann Ebbinghaus’s forgetting curve, the memory of people starts forgetting after 10 min more than 50 % after one hour. The reason that people typically record words on note is for reminding the words. If people don’t consciously search the recorded words on note, the words will be forgotten. This paper presents the information reminder system that helps a user to remind words. This system helps a user by giving the word highlighting the shades in case of a word that appear during web surfing.

Design of a Smartphone-Based Driving Habit Monitoring System

Cars have supplied rapidly, and most households now own at least one car. With increase of interest in the car, many people also focus on the scheme to saving for maintenance cost and prevention of traffic accident. Vehicle manufacturers provide Telematics and Connected-car services, however, it is possible only the car equipped module for the services. And it is inevitable to pay additional high price cost. By 2014, there are only 7 million cars with module for Connected-Car service in the whole world. Each manufacturer provides independency and exclusive platform service. In this paper, we propose common service of driving habit monitoring. This can provide driving habit monitoring service to anyone who has a smartphone and a car equipped with low price IoT devices. We analysis driving habit using vehicle operating data, user activity data and GPS based on OBD-II and smart phone.

Design and Implementation of Priority Retrieval Technique based on SIF

In traditional Publish/Subscribe system, the first procedure to deliver event from publisher to subscriber is that publisher publishes publisher`s event to broker. Next step is that broker checks simple binary notion of matching : an event either matches a subscription or it does not. Lastly, broker delivers the event matched with subscriptions to the corresponding subscribers. In this system, information delivery has been accomplished in one way only. However, current some applications require two way delivery between subscriber and publisher. Therefore, we initiate an extended Publish/Subscribe system that supports two way delivery. Extended Publish/Subscribe system requires additional functions of delivering subscription to publisher and especially deciding top-n subscriptions using priority because broker might has a number of subscriptions. In this paper, we propose two priority retrieval techniques based on SIF using IS-List with deciding priority among subscriptions and defining SIF(Specific Interval First). The performance measurements show that RSO(resulting set sorting) technique results in better performance in index creation time and ITS&IS(insertion time sorting and inverse search using stack) technique results in better performance in search time.

Indexing Moving Objects for Trajectory Retrieval on Location-Based Services

Due to the continuous growth of wireless communication technology and mobile equipment, the history management of moving object is important in a wide range of location-based applications. To process queries for history data, trajectories, we generally use trajectory-preserving index schemes based on the trajectory preservation property. This property means that a leaf node only contains segments belonging to a particular trajectory, regardless of the spatiotemporal locality of segments. The sacrifice of spatiotemporal locality, however, causes the index to increase the dead space of MBBs of non-leaf nodes and the overlap between the MBBs of nodes. Therefore, an index scheme for trajectories shows good performance with trajectory-based queries, but not with coordinate-based queries, such as range queries. We propose new index schemes that improve the performance of range queries without reducing performance with trajectory based queries.