• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.54-56
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• 2000

데이터 마이닝 작업에서 사용되는 데이터의 크기는 그 특성상 대규모를 이루고 있다. 이러한 대규모의 데이터로부터 규칙을 추출하는 작업은 많은 배용이 소모된다. 또한 급변하는 데이터는 이미 발견된 마이닝 패턴에 대하여 현저한 패턴은 약한 패턴으로, 반면 약한 패턴은 현저한 패턴으로 변화시키는 요인이 되고 있다. 이러한 동적 환경에서는 기존의 데이터베이스 특정시간의 스냅 샷 형태의 데이터를 이용하였던 마이닝 방법으로는 적당하지 못하다. 따라서 이 논문에서는 동적인 환경에서 적용할 수 있는 점진적 마이닝 방법을 제시하고, 점진적 마이닝 작업이 효과적으로 수행 가능한 능동시스템 모델을 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.271-273
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• 2009

유비쿼터스 컴퓨팅은 환경 및 사용자의 상황을 필요로 하는 곳에 센서 노드들을 부착해 환경 정보를 수집하여 사용자에게 적합한 서비스를 제공하는 기술이다. 그러므로 사용자가 원하는 서비스를 다양한 상황에 맞게 적절한 서비스를 제공하는 것이 중요하다. 이 논문에서는 사용자의 상황을 고려하고 지능적인 서비스를 제공하기 위해 컨텍스트 온톨로지 기반의 능동 마이닝 프레임워크를 제안한다.

• Journal of Power Electronics
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• v.19 no.1
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• pp.58-67
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• 2019

This study presents a new portable eight-output light emitting diode (LED) driver. The eight output-channels are divided into two equal groups, and their output powers can be controlled individually by three active switches. In addition, a simple capacitor-based passive current balancing circuit (CBC) is employed in each port to guarantee that the currents of the four LEDs are the same. When compared with the conventionally used separate two-output isolated converters, the proposed one uses one less active switch. Moreover, zero-voltage-switching (ZVS) is achieved, which improves the power efficiency of the driver. Finally, a highly compact prototype is built, which can reach an efficiency of 94.6%.

• Tunnel and Underground Space
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• v.10 no.4
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• pp.533-543
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• 2000

Deformation behavior and stability of vertical pipeline subjected to underground excavation have been studied by means of numerical analysis. Vortical ground displacements cause the pipe to be compressed, while horizontal ones cause it to be bent. In that region the vertical pipeline meets with the induced compressive stress and bending stress. In addition horizontal rock stress subjected to underground excavation may press the tube in its radial direction and it finally produces the tangential stress of pipe. In this study active gas well system is considered as an example of vertical pipelines. Factor analysis has been conducted which has great influence on the pipeline behavior. Three case studies are investigated which have the different pillar widths and gas well locations in pillar. For example, where overburden depth is 237.5 m and thickness of coal seam is 2.5 m, chain pillar of 45.8 m width in the 3-entry longwall system is proved to maintain safely the outer casing of gas welt which is made of API-55 steel, 10$\frac{3}{4}$ in. diameter and 0.4 in. thickness. Finally an active gas well which was broken by longwall mining is analyzed, where the induced shear stress turn out to exceed the allowable stress of steel.

• Journal of Electrochemical Science and Technology
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• v.9 no.3
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• pp.202-211
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• 2018

In this work, Fe-Pd alloy films have been electrodeposited on different substrates using an electrolyte containing $[Pd(NH_3)_4]^{2+}$ (0.02 M) and $[Fe-Citrate]^{2+}$ (0.2 M). The influences of substrate and overpotential on chemical composition, nucleation and growth kinetics as well as the electrodeposited films morphology have been investigated using energy dispersive X-ray spectroscopy (EDS), current-time transients, scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD) patterns. In all substrates - brass, copper and sputtered fluorine doped tin oxide on glass (FTO/glass) - Fe content of the electrodeposited alloys increases by increasing the overpotential. Also the cathodic current efficiency is low due to high rate of $H_2$ co-reduction. Regarding the chronoamperometry current-time transients, it has been demonstrated that the nucleation mechanism is instantaneous with a typical three dimensional (3D) diffusion-controlled growth in the case of brass and copper substrates; while for FTO, the growth mode changes to 3D progressive. At a constant overpotential, the calculated number of active nucleation sites for metallic substrates is much higher than that of FTO/glass; however by increasing the overpotential, the number of active nucleation sites increases. The SEM micrographs as well as the XRD patterns reveal the formation of Fe-Pd alloy thin films with nanostructure arrangement and ultra-fine grains.

• Journal of Preventive Medicine and Public Health
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• v.40 no.4
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• pp.278-284
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• 2007

Despite extensive researches and pre-market clinical trials, only limited information on the adverse drug reactions (ADRs) of a drug can be collected at the time of market approval from regulatory agency. ADRs constitute a major public health problem. Post-marketing surveillance of drugs is important to detect signals for ADR. In Korea, one of the main methods for monitoring the safety of marketed drugs is spontaneous reporting system of suspected ADRs. Re-examination and re-evaluation system are in force for monitoring safety of new market approval drugs and currently under marketing drugs, respectively. Recently, regional pharmacovigilance centers were designated from Korean Food and Drug Administration for facilitating ADR surveillance. Over recent years, with the development of information technology, there has been an increased interest in establishing data mining system for detecting signals from Health Insurance Review Agency database. The purpose of this paper is to review the current status of Korean ADR surveillance system and suggest the possible solutions for developing active pharmacovigilance system in Korea.

• Economic and Environmental Geology
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• v.31 no.3
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• pp.223-233
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• 1998

The environments in the vicinity of the Dalseong mine has been much contaminated by heavy metals related to CuW ore deposit, which is of hydrothermal pipe type mineralized by quartz monzonite in the andesitic rocks. Chalcopyrite and wolframite are major ore minerals and sphalerite, galena and others are associated. To investigate the contamination of heavy metals in plants, samples of plants and soils were analysed by ICP for Fe, Mn, Cu, Pb, Zn, Ni, Co, Cd and Cr. Most of ore-related heavy metals are anomalously high in plants and soils, which were contaminated by the development of Taehan Tungsten Mining Company. The mine produced 48,704 tons (M/T) of 4 wt.% Cu and 1,620 tons (S/T) of 70 wt.% of $WO_3$ during active mining activity from 1961 to 1971 but was closed in 1975. Wild plants growing at the mine area may be used to remove heavy metals form soils, which cause contaminations of plants, stream waters and groundwaters in the vicinity of the mine.

• Human Ecology Research
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• v.60 no.1
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• pp.21-38
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• 2022

This study uses text mining compares and contrasts consumers' social media discourses on dietary related zero-waste movement before and after COVID-19. The results indicate that the amount of buzz on social networks for the zero- waste movement has been increasing after COVID-19. Additionally, the results of frequency analysis and topic modeling revealed that subjects associated with zero-waste movement were more diversified after COVID-19. Although the results of a sentiment analysis and word cloud visualization confirmed that consumers' positive responses toward the zero-waste have been increasing, they also revealed a need to educate and encourage those who are still not aware of the need for zero-waste. Finally, consumers mentioned only a small number of companies participating in zero-waste movement on SNS, indicating that the level of active involvement by such companies is much lower than that of consumers. Theoretical and educational implications as well as those for government policy-making are considered.

• Journal of the Korean Wood Science and Technology
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• v.50 no.6
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• pp.375-391
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• 2022

Improving public awareness of wood is crucial for expanding the use of wood and establishing a wood culture. In this study, the environment and trends of the public's wood utilization were analyzed using a questionnaire survey and online text mining at a time when eco-friendly practices are gaining popularity. As a result of reducing climatic and environmental concerns and its positive physical and psychological effects, the use of wood is predicted to rise in areas intimately connected to everyday living, such as wood furniture, wooden structures, and interior materials. Nonetheless, there was a negative awareness that wood was expensive, difficult to maintain, and associated with deforestation. The correlations between wood-related search terms on major Korean portal sites were analyzed and categorized into five groups: Wooden architecture, cultural education, woodworking, wood industry, and wood policy. As a building material, wood was seen as more traditional and friendly than reinforced concrete and stone. Eighty-six percent of respondents expected to utilize wood as a building material in the future, regardless of whether the wood is domestically produced or imported. Sixty-five percent responded favorably about the effects of wood on the health of wooden home inhabitants. It is believed that both active publicity and quantifiable value analysis of human and environmental friendliness are required to increase pro-environment awareness of wood utilization.

• Steel and Composite Structures
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• v.45 no.5
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• pp.715-728
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• 2022

Closed steel supports of different shapes are used in mining and underground constructions. The supports are prefabricated from rolled, usually robust, steel profiles. The load carrying capacity of a support is considerably influenced by the active loading and passive forces. The passive forces are induced by interactions between the support and the surrounding rock mass. The analysis herein comprises three parts: The first part consists of structural geometry processing. The second part involves finding the numerical solution of a statically indeterminate structure for a specified load. The third part is calculation of the load carrying capacity and the components of internal forces and deformations. For this, the force method and numerical integration are used. The Winkler model is applied when the support interacts with the surrounding environment. The load carrying capacity is limited by the slip resistance of the connected parts and it is limited by reaching the ultimate state of the profile. This paper serves as a comprehensive reference for the determination of the load carrying capacity of closed steel supports and includes stepwise derivations of the governing formulas.