• The Journal of Korea Robotics Society
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• v.4 no.2
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• pp.147-154
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• 2009

Visions of ubiquitous robotics and ambient intelligence involve distributing information, knowledge, computation over a wide range of servers and data storage devices located all over the world, and integrating tiny microprocessors, actuators, and sensors into everyday objects as well in order to make them smart. In this paper, we introduce our ongoing research effort aimed at realizing ubiquitous robots in an information structured space. For this, a ubiquitous space and ambient intelligent systems for a librarian robot are introduced and the RFID technology based approach for these systems is described.

• Journal of the Korean Society for information Management
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• v.24 no.1 s.63
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• pp.103-120
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• 2007

Node is the semantic unit and a part of structured document. Information retrieval from structured documents offers an opportunity to go subdivided below the document level in search of relevant information, making any element in an structured document a retrievable unit. The node-based document retrieval constitutes several similarity calculating methods and the extended node retrieval method using structure information. Retrieval performance is hardly influenced by the methods for determining document similarity The extended node method outperformed the others as a whole.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.12
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• pp.1633-1638
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• 1988

This paper proposes the lattice-structured space subdivision method using bounding volume to reduce a great number of ray-surface intersection calculations in ray tracing algorithm for the computer graphics. We show that this method reduced 50%-70% calculations compard to pre-exist method by experiments.

• Journal of Information Processing Systems
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• v.18 no.3
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• pp.374-388
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• 2022

Database systems usually have many parameters that must be configured by database administrators and users. RocksDB achieves fast data writing performance using a log-structured merged tree. This database has many parameters associated with write and space amplifications. Write amplification degrades the database performance, and space amplification leads to an increased storage space owing to the storage of unwanted data. Previously, it was proven that significant performance improvements can be achieved by tuning the database parameters. However, tuning the multiple parameters of a database is a laborious task owing to the large number of potential configuration combinations. To address this problem, we selected the important parameters that affect the performance of RocksDB using random forest. We then analyzed the effects of the selected parameters on write and space amplifications using analysis of variance. We used a genetic algorithm to obtain optimized values of the major parameters. The experimental results indicate an insignificant reduction (-5.64%) in the execution time when using these optimized values; however, write amplification, space amplification, and data processing rates improved considerably by 20.65%, 54.50%, and 89.68%, respectively, as compared to the performance when using the default settings.

• Journal of Biosystems Engineering
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• v.24 no.2
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• pp.159-166
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• 1999

A system to extract continuously the real 3-D geometric fearture information from 2-D image of an object, which is fed randomly via conveyor has been developed. Two sets of structured laser lightings were utilized. And the laser structured light projection image was acquired using the camera from the signal of the photo-sensor mounted on the conveyor. Camera coordinate calibration matrix was obtained, which transforms 2-D image coordinate information into 3-D world space coordinate using known 6 points. The maximum error after calibration showed 1.5 mm within the height range of 103mm. The correlation equation between the shift amount of the laser light and the height was generated. Height information estimated after correlation showed the maximum error of 0.4mm within the height range of 103mm. An interactive 3-D geometric feature extracting software was developed using Microsoft Visual C++ 4.0 under Windows system environment. Extracted 3-D geometric feature information was reconstructed into 3-D surface using MATLAB.

• Korean Institute of Interior Design Journal
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• no.31
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• pp.71-78
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• 2002

Understanding the consumer changed life styles are integrated, mutual complement for user's worth and consciousness, the life of consumption, etc. Recently, Apartment Model House has built for distribute to Apartment house When they enter the units after 2 or 3 years. So, Interior designer make an inference from the changed life styles. But, We don't have enough information to trace the design trend about residential space design. Design database is correspond with interior space and structured entity relationship. There are three parts in this Database, Type, Elements and Relation information. Type are composed size, ages, style, and space, Elements are materials and space elements. Relation information are publishing, designer, exhibition, construction company, remodeling, Intoner design and User favorite styles are the development in web environment. This research supplies interior design information for Web environment and trend analysis supports collaboration with development of interior design information database.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.9
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• pp.107-115
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• 2018

It is a basic study to speculate the old form of urban space. The purpose of the study is to study how to build a database that can synthesize multiple data describing the past. In particular, It was focused to the first half time of Seoul City during the Chosun Dynasty. Data is structured systematically and inclusively through digitizing, visualization, and specification. Through this, the city's urban space scene is reconstructed as a map of the city. And maps include various humanities information explaining the aspects of space activities. And it will become a system that will facilitate data management and improve the clarity of information.

• Journal of Intelligence and Information Systems
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• v.14 no.4
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• pp.161-178
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• 2008

Development and realization of ubiquitous services in physical space is now in progress to develop ubiquitous smart space (USS). As the development methodologies for USS, scenario development is performed before requirement analysis and design, or vice versa. However, even though lots of redundant elements could be found between scenarios and requirement analysis results, a sort of structural approaches to join them together has been still very rare. Hence, the aim of this paper is to propose a system which generates ubiquitous service senarios and system analysis specifications according to a novel integration methodology. To do so, scenario and requirement analysis are integrated in a structured manner.

• Journal of KIISE
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• v.41 no.12
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• pp.1026-1034
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• 2014

Recently, flash storages devices have become popular. Log-structured file systems (LFS) are suitable for flash storages since these can provide high write performance by only generating sequential writes to the flash device. However, LFS should perform garbage collections (GC) in order to reclaim obsolete space. Recently, a slack space recycling (SSR) technique was proposed to reduce the GC overhead. However, since SSR generates random writes, write performance can be negatively impacted if the random write performance is significantly lower than sequential write performance of the target device. This paper proposes a partial garbage collection technique that copies only a part of valid blocks in a victim segment in order to increase the size of the contiguous invalid space to be used by SSR. The experiments performed in this study show that the write performance in an SD card improves significantly as a result of the partial GC technique.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.12
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• pp.963-967
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• 2009

The Log-structured File System (LFS) collects all modified data into a memory buffer and writes them sequentially to a segment on disk. Therefore, it has the potential to utilize the maximum bandwidth of storage devices where sequential writes are much faster than random writes. However, as disk space is finite, LFS has to conduct cleaning to produce free segments. This cleaning operation is the main reason LFS performance deteriorates when file system utilization is high. To overcome painful cleaning and reduced performance of LFS, we propose the segment space recycling (SSR) scheme that directly writes modified data to invalid areas of the segments and describe the classification method of data and segment to consider locality of reference for optimizing SSR scheme. We implement U-LFS, which employs our segment space recycling scheme in LFS, and experimental results show that SSR scheme increases performance of WOLF by up to 1.9 times in HDD and 1.6 times in SSD when file system utilization is high.