• The Transactions of the Korea Information Processing Society
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• v.4 no.9
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• pp.2173-2184
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• 1997

Among spatial queries handled in spatial database systems, nearest neighbor queries to find the nearest spatial object from the given locaion occur frequently. The number of searched nodes in an index must be minimized in order to increase the performance of nearest neighbor queries. An Existing approach considered only the processing of an nearest neighbor query in a two-dimensional search space and could not optimize the number of searched nodes accurately. In this paper, we propose the optimal search distance and prove its properties. The proposed optimal search distance is the measurement of a new search distance for accurately selecting the nodes which will be searched in processing nearest neighbor queries. We present an algorithm for processing the nearest neighbor query by applying the optimal search distance to R-trees and prove that the result of query processing is correcter than the existing approach.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.217-222
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• 2014

In this paper, I propose an efficient data search system using data partitioning algorithm in Microsoft Excel. I propose searching algorithm to retrieve data quickly using VBA functioning in the Excel. This algorithm is to specify the sheet you are looking for. Once the sheet is specified, the algorithm searches the beginning and the end of the data in the sheet. The algorithm compares intermediate values and key words, from the starting position of the cell. In this way, it will search data to the end. This proposed algorithm was implemented and tested in the Excel system using VBA program. The experimental results showed that the performance was better than that of the conventional sequential search method.

• Journal of KIISE:Databases
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• v.36 no.4
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• pp.314-320
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• 2009

Skyline queries have recently received considerable attention in the searching services. The skyline contains interesting objects that are not dominated by any other objects on all dimensions. Many related works have processed a skyline on static data or on moving objects in Euclidean space. However, this paper assumes that the point of a skyline query continuously moves in road networks. We propose a new method that efficiently processes continuous skyline queries in road networks through pre-computed shortest range data of objects. Our experiments show that the proposed method is about 100 times faster than previous methods in terms of query processing time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.671-674
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• 2013

In this paper, we propose an efficient data search system using data partitioning algorithm in Microsoft Excel. We propose to retrieve the data quickly using VBA functioning Excel. This algorithm is to specify the sheet you are looking for. Once the sheet is specified, it searches the beginning and the end of the data in the sheet. It compares desired key words and intermediate values, starting from the position of the cell. In this way, it will search data to the end. This proposed algorithm was implemented and tested using actual VBA program. The experimental results showed that the performance was more excellent than that of the conventional search method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.8
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• pp.1620-1625
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• 2004

To advance fisheries, we set developmental directions of fishery information by grasping present situations and analyzing maritime & fisheries issues. We promote various policies through effective systematical information data bases, based on both control and utilization of oceanic resources. For these puposes, it is imperative that we set up fisheries communication networks. There are satellite assisted informational networks to assist fishing vessels with their marine based movements. However, there's no hope for poorly equipped fishermen to adopt this network because of extravagant network call charges. So we think that using existing SSB communication system is the best plan. We organize fishery communication network by HF SSB communication which doesn't have operational costs. We build wireless transmitting and receiving stations that are basic systems of informnation, and equip wireless data communication systems by the use of wireless communication network protocols in coastal stations. It is necessary that a fish boat has a terminal device for wireless data communication. In this research we can conclude that if we transmit the location of a fishing boat in-real time through GPS channels then we propose that some methods be formulated to able terminal devices on fishing boats to collect various types of information, such as meteorological and oceanic conditions.

• Journal of KIISE:Databases
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• v.36 no.5
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• pp.374-385
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• 2009

Flash memory becomes increasingly popular as data storage for various devices because of its versatile features such as non-volatility, light weight, low power consumption, and shock resistance. Flash memory, however, has some distinct characteristics that make today's disk-based database technology unsuitable, such as no in-place update and the asymmetric speed of read and write operations. As a result, most traditional disk-based database systems may not provide the best attainable performance on flash memory. To maximize the database performance on flash memory, some approaches have been proposed where only the changes made to the database, i.e., logs, are written to another empty place that has born erased in advance. In this paper, we propose an efficient log management scheme for flash-based database systems. Unlike the previous approaches, the proposed approach stores logs in specially allocated blocks, called log blocks. By evenly distributing logs across log blocks, the proposed approach can significantly reduce the number of write and erase operations. Our performance evaluation shows that the proposed approaches can improve the overall system performance by reducing the number of write and erase operation compared to the previous ones.

• Journal of KIISE:Databases
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• v.37 no.2
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• pp.121-126
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• 2010

This paper proposes an efficient index scheduling technique for kNN query processing in multiple wireless broadcast channel environment. Previous works have to wait for the next cycle if the required child nodes of the same parent node are allocated in the same time slot on multiple channel. Our proposed method computes the access frequencies of each node of R tree at the server before the generation of the R-tree index broadcast schedule. If they have high frequencies, we allocate them serially on the single channel. If they have low frequencies, we allocate them in parallel on the multiple channels. As a result, we can reduce the index node access conflicts and the long broadcast cycle. The performance evaluation shows that our scheme gives the better performance than the existing schemes.

• Journal of KIISE:Software and Applications
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• v.36 no.3
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• pp.217-225
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• 2009

In case of sketching a conceptual model in 3D space, it's not easy for designer to recognize the depth cue accurately and to draw a model correctly in short time. In this paper, multi-strokes based sketch is adopted not only to reduce the error of input point but to substantiate the shape o) the conceptual design effectively. The designer can see the drawing result immediately after stroking some curves. The shape can also be modified by stroking curves repeatedly and be confirmed the modified shape in real time. However, the multi-strokes based sketch needs to manage the great amount of input data. Therefore, the drawing space is divided into the limited spatial cubical grids and the movable infernal vertex in each spatial grid is implemented and used to define the surface by the multi-strokes. We implemented the spatial sketching system which allows the concept designer's intention to 3D model data efficiently.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.5 no.5
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• pp.167-176
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• 2015

Due to the variety of tourist attractions, many people of the world are visiting annually in Mediterranean area. In this paper, we analyze Mediterranean tourism impact by specific events such as the Arab Spring. In details, we make several density maps based on the position and time information of the geo-tagged photos extracted from Panoramio which is a representative photo sharing website. These density maps should be used to analyze how can specific events affect on Mediterranean tourism. To do this, first, a spatial database is constructed using geo-tag and time information of photo data extracted from Panoramio. Using GIS tool, then, several density maps are produced after performing density process based on spatial databases. Based on these density maps, finally, we analyze visually on Mediterranean tourism impact according to before, progress, and after of the Arab Spring.

• Journal of KIISE:Databases
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• v.35 no.3
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• pp.208-217
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• 2008

Sensors have a function to gather environment-related information operating by small-size battery in sensor networks. The issue related with energy is still an important in spite of the recent advancements in micro-electro-mechanical-system(MEMS) related techology. Generally it is assumed that replacement or rechargement of battery power in sensor is not feasible and a message send operation may spend at least 1000 times battery than a local operation. Thus, there have been several kinds of research efforts to lessen the number of unnecessary messages by maintaining the information of the other neighboring(or all) sensors. In this paper, we propose an index structure based on parent-children relationship to the purpose. Namely, parent node gathers the set of location information and MBA per child. It's named PH and may allow to process the range query with higher accurate and small size information. Through extensive experiments, we show that our index structure has better energy consumption.