• 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 the Korea Institute of Building Construction
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• v.5 no.4 s.18
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• pp.165-171
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• 2005

Nowadays, a source of all water, which has been spent by a lot of people, is the rainwater The rainwater is directly relating human being' life. According to how to use rainwater. human being' life is abundant or poor. Due to the lack of underground filtration quantity, the water circulation of the city is discontinued and the underground ecosystem is destroyed. This study suggest that the unused underground space of building and temporary structure can be used into rainwater storage tank in the facility to use rainwater. Moreover, in this study, while the building is constructed, It is showed that the water used in construction can be replaced in the rainwater.

• Magazine of korean Tunnelling and Underground Space Association
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• v.4 no.3
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• pp.23-37
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• 2002

프로덕트 관리를 통하여 발주자에게 제공해야 하는 산출물에 대한 구체적인 특성 및 제원이 규명되면, 프로젝트 관리를 통하여 발주자에게 제공해야 하는 산출물에 대한 구체적인 작업 및 자원이 규명된다. 또한 프로젝트 관리는 설정된 공기, 공사비, 품질 등의 프로젝트 목표를 만족시킴으로써 그 역할을 수행하게 된다. 최근 국내외 프로젝트의 입찰 과정을 볼 때 발주자의 요구사항이 점점 까다로워지고 제약 조건은 더욱 강화되고 있는 추세이다. 따라서 몇몇 사람의 특화된 감각이나 과거 수행된 계획의 답습만으로는 이러한 추세에서 제대로 대응하여 프로젝트 목표를 달성하는 것은 매우 힘든 실정이다. 본 기술보고에서는 프로세스를 통하여 프로젝트 계획을 개발함으로써 과학적이며 체계적인 프로젝트 관리가 이루어질 수 있음을 보여주고자 한다.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.242-245
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• 2005

The rotating flow in the space between co-rotating disks is of considerable importance in information storage systems. Hard disk drivers(HDD) in computer are used extensively as data storage capacity. The trend in the computer industry to produce smaller disk drives rotating at higher speed requires an improved understanding of fluid motion in the space between disks. In this study, we have tried LES model for inner-disk flowfield to investigate the flow disturbance and the flow structure driven by co-rotating disks. The boundary pattern between inner region and outer region obtained lobe-shape structure clearly and its number has been validated on experimental data by our previous study. We obtain the spectra of velocity and pressure components with several frequencies. We revealed there are two kinds of disturbances, one is global wave propagation and another is local wave propagation on Ekman boundary layer.

• Journal of The Korean Digital Architecture Interior Association
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• v.7 no.1
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• pp.29-34
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• 2007

Purpose of this paper is find the similarity and dissimilarity of Korean, Chinese and Japanese traditional furnitures for storage. Also this paper tries to have a comparative analysis on life style, characteristics of housing space and furniture's form of three countries. The study can be summarized as follows. First, space scale and seat levels of three countries are related to furniture's height and form, so that Chinese furniture have over scale than human, and Japanese furniture have the type of box for stacking. Second, the way of heating and materials of floors are concerned with the type of furniture's legs. Third, even if these dissimilarities, the aesthetic characteristics of three countries furniture would be a data base for making design identity of East Asian modern housing furniture.

• Transactions of the Society of Information Storage Systems
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• v.2 no.2
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• pp.156-162
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• 2006

In this paper, we have investigated the disc warping in high-speed slim-type optical disc drive. The track density as well as high rotational speed of the information storage devices must be increased to enhance their recording capacity and data transfer rate. Generally, ODD used in the Lap-top computer has small inner space. So, the flow instability of the inner space is increased rapidly with its rotational speed. In extreme case, the flow instability may cause the malfunction of the read/write pick-up of drives. The experiments and numerical analysis were carried out for several cases and the result shows the influence of airflow to the disc warping.

• Environmental Engineering Research
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• v.20 no.4
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• pp.397-402
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• 2015

SCR has been popularly approved as one of the most effective means for NOx emission control in heavy-duty and medium-duty vehicles currently. However, high urea dosing would lead to ammonia slip. And $NH_3$ sensor for vehicle emission applications has not been popularly used in real applications. This paper presents experimental studies on the diesel engine urea-SCR system by using a double NOx sensor system that is arranged in the downstream of the SCR catalyst based on ammonia cross-sensitivity. It was shown that the NOx conversion efficiency rised as $NH_3/NOx$ increases and the ammonia slip started from the $NH_3/NOx$ equal to 1.4. The increase of temperature caused high improvement of the SCR reaction rate while the space velocity had no obvious change. The ammonia slip was in advance as catalyst temperature or space velocity increase and the ammonia storage reduced as catalyst temperature or space velocity increase. The NOx real-time conversion efficiency rised as the ammonia accumulative storage increase and reached the maximum value gradually.

• Journal of KIISE:Software and Applications
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• v.26 no.10
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• pp.1230-1236
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• 1999

한글 폰트는 서로 상반된 장단점을 가진 조합형 폰트와 완성형 폰트로 구분된다. 완성형 폰트는 조합형과 비교하여 우수한 품질을 가지지만 폰트 제작에 더 많은 시간과 노력을 요구한다. 특히 완성형 폰트는 폰트내의 중복된 자소들의 정보를 중복해서 저장하므로 폰트 저장에 필요한 공간이 더 많이 필요하다. 본 논문에서는 트루타입의 합성 글립(Composite Glyph)을 이용하여 이들 중복된 자소를 최소화한 완성형 폰트를 구성하였다. 실험 결과 생성된 완성형 트루타입 폰트는 기존 완성형 폰트와 유사한 고수준의 품질을 유지하면서, 샘체의 경우 기존 폰트의 57.6%, 명조체의 경우 73.0%의 저장공간을 절약할 수 있었다.Abstract Hangul fonts are classified into 2 categories, complete type and combination type which have their own strength and weakness. The complete type shows a high quality of fonts, while the combination type takes less time, efforts, and storage space to develop. Since the Hangul makes a syllable by combining consonants with vowels, the complete type has many duplicates and requires a large storage space to save them. We present a method that minimizes the duplicates of the complete type of the Hangul using the composite glyph of TrueType. New fonts had high quality and saved storage space, for example Sam saved 57.6% and Myungjo saved 73.0% compared to old.

• Journal of the Korean Society of Food Culture
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• v.31 no.1
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• pp.51-63
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• 2016

The aim of this study was to investigate food culture represented by the grain yard, water well, kitchen, and meat storage space which were depicted in the mural painting of An-Ak tomb No. 3. The mural paintings of An-Ak tomb No. 3 were compared with those of ancient Chinese tombs before the 4th century in order to understand their characteristics. Above all, the tomb murals describe the form and function of the stove (buttumak) as well as the cuisine using the cauldron (sot) and steamer (siru) in a very interesting manner. The meat storage space of An-Ak tomb No. 3 shows whole carcasses of animals such as roe deer, dog, and pig. However, Chinese murals show that while small animals such as soft-shelled turtle, fish, chicken, duck, pheasant, rabbit, etc. were stored as whole carcasses without being cut into pieces, large animals such as cows and pigs were slaughtered and each piece of their carcasses such as the head, thigh, meat loaf, and cardiopulmonary part was separately depicted. These tomb murals vividly describe the food culture of Koguryo and China before the 4th century.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.257-266
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• 1999

This paper presents a method of seismic analysis for a cylindrical liquid storage structure on/in horizontally layered half.space considering the effects of the interior fluid and exterior soil medium in the frequency domain. To capture the essence of fluid-structure-soil interaction effects effectively, a mixed finite element with two-field (u, p) approximation is employed to model the compressive inviscid fluid, while the structure and soil medium are presented by the 3-D axisymmetric finite elements and dynamic infinite elements. The present FE-based method can be applied to the system with complex geometry of fluid region as well as with inhomogeneous near-field soil medium, since it can directly model both the fluid and the soil. For the purpose of verification, dominant peak frequencies in transfer functions for horizontal motions of cylindrical fluid storage tanks with rigid massless foundation on a homogeneous viscoelastic half.space are compared with those by two different added mass approaches for the fluid motion. The comparison indicates that the Present FE-based methodology gives accurate solution for the fluid-structure-soil interaction problem. Finally, as a demonstration of versatility of the present study, a seismic analysis for a real-scale LNG storage tank embedded in layered half.space is carried out, and its member forces along the height of the structure are compared with those by an added mass approach developed by the present writers.