• 한국환경과학회지
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• 제31권7호
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• pp.637-652
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• 2022

In this study, the contributions of emissions (foreign and domestic) and atmospheric physical and chemical processes to PM_2.5 concentrations were evaluated during a high PM_2.5 episode (March 24-26, 2018) observed on the Jeju Island in the spring of 2018. These analyses were performed using the community multi-scale air quality (CMAQ) modeling system using the brute-force method and integrated process rate (IPR) analysis, respectively. The contributions of domestic emissions from South Korea (41-45%) to PM_2.5 on the Jeju Island were lower than those (81-89%) of long-range transport (LRT) from China. The substantial contribution of LRT was also confirmed in conjunction with the air mass trajectory analysis, indicating that the frequency of airflow from China (58-62% of all trajectories) was higher than from other regions (28-32%) (e.g., South Korea). These results imply that compared to domestic emissions, emissions from China have a stronger impact than domestic emissions on the high PM_2.5 concentrations in the study area. From the IPR analysis, horizontal transport contributed substantially to PM_2.5 concentrations were dominant in most of the areas of the Jeju Island during the high PM_2.5 episode, while the aerosol process and vertical transport in the southern areas largely contributed to higher PM_2.5 concentrations.

• 한국지역지리학회지
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• 제4권2호
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• pp.165-182
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• 1998

관광지는 관광객에 의하여 이용이 지속될 때 관광목적지로서 그 생명력과 가치를 유지할 수 있으며, 그렇지 못할 경우 그 관광지는 곧 쇠퇴해 버리게 된다. 따라서 본 연구는 버틀러에 의해 제시된 관광목적지 수명주기이론을 바탕으로 한국에 분포하는 온천관광지 중 현재 이용중에 있는 46개 온천지구를 대상으로 수명주기 단계와 분포특성 및 이용객의 행태를 분석하여 관광목적지가 쇠퇴하지 않고 더욱 활성화하는 방안을 모색하고자 하였다. 분석대상으로 삼은 46개 온천지구 중 개발단계가 29개지구로 가장 많은 비중을 차지하고 있으며 성장단계 4개지구, 성숙단계 5개지구, 침체 및 쇠퇴단계 5개지구, 재활단계 3개지구로 나타났다. 이러한 수명주기에 영향을 미치는 분포특성 및 이용객의 행태를 분석한 결과 지형적 위치, 접근도에 의한 분포특성이 수명주기에 많은 영향을 미치는 것으로 나타났으며, 관광객들의 관광행태가 단일목적의 관장에서 다목적 관광으로 전환되고 있는 것으로 나타났다. 따라서 온천관장저의 활성화 방안으로는 온천지구의 확대지정과 온천수 보존, 장기체류형 관광지로의 복합개발, 도로망의 확충, 주변관광자원의 활용, 공동급수의 시행, 관광특구의 지정 등 관광객을 견인할 수 있는 새로운 관광매력물을 꾸준히 개발해야 할 것이다.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2003년도 정기총회 및 추계학술대회
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• pp.221-227
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• 2003

The characteristics of Japanese housing stock is as follows. 1. It is predicted that population from 2010 and general household from 2015 will decrease. The aging speed in Japan is faster than several advanced nations. 2. Housing shortage has resolved from 1973. In 1998, dwelling number per household is 1.13 houses and vacant dwelling rate is 11.5 percents. 3. Dwelling level of rented dwelling is lower than owner occupied houses; for instance, floor area of the former is one third of the latter. As for a household of thirties, family type household lived in rented houses reached 60 percents, it reveals that the demand exceeds the supply. 4. Houses constructed before the new earthquake resistant standard enforced from 1981 year is the half of the whole, housing improvement is needed in the future. Future housing market is changed to practical use of housing stock. Consequently, expansion of multi-habitation used a vacant housing of city dwellers, activation of the used houses distribution, growth of dwelling reform market, and activation of the rented houses are expected.

• Structural Engineering and Mechanics
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• 제71권1호
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• pp.45-56
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• 2019

A modified mechanical model of pre-pressed spring self-centering energy dissipation (PS-SCED) brace is proposed, and the hysteresis band is distinguished by the indication of relevant state variables. The MDOF frame system equipped with the braces is formulated in an incremental form of linear acceleration method. A multi-objective genetic algorithm (GA) based brace parameter optimization method is developed to obtain an optimal solution from the primary design scheme. Parameter sensitivities derived by the direct differentiation method are used to modify the change rate of parameters in the GA operator. A case study is conducted on a steel braced frame to illustrate the effect of brace parameters on node displacements, and validate the feasibility of the modified mechanical model. The optimization results and computational process information are compared among three cases of different strategies of parameter change as well. The accuracy is also verified by the calculation results of finite element model. This work can help the applications of PS-SCED brace optimization related to parameter sensitivity, and fulfill the systematic design procedure of PS-SCED brace-structure system with completed and prospective consequences.

• 한국환경과학회지
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• 제23권2호
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• pp.249-259
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• 2014

This paper investigates the characteristics of high $PM_{2.5}$ episodes occurred at Anmyeondo area in spring time, 2009. The monthly mean $PM_{2.5}$ concentration during April was the highest in the year and especially, high levels of $PM_{2.5}$ exceeding standard regulation level were sustained consecutively during 5 to 13 April. To analyze more detailed $PM_{2.5}$ characteristics, numerical simulations were carried out using CMAQ(Community Multi-scale Air Quality) with IPR(Integrated Process Rate) and DDM-3D(Decoupled Direct Method). $PM_{2.5}$ level was lower in daytime than that in nighttime due to vigorous vertical mixing during daytime. The chemical composition was showed that ratio of primary ion components such as sulfate($SO_4{^{2-}}$), nitrate($NO_3{^-}$) and ammonium($NH_4{^+}$) were nearly half of total amount of $PM_{2.5}$. Aerosol and transport process dominantly contributed to $PM_{2.5}$ concentration in Anmyeondo area and contribution rate of local emissions was nearly zero since Anmyeondo area has rare anthropogenic PM emission sources. DDM-3D analysis result showed that $PM_{2.5}$ in Anmyeondo area was influenced by emissions from Shanghai and Shandong region of China.

• 한국정보통신학회논문지
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• 제11권3호
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• pp.479-485
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• 2007

본 논문에서는 사실적인 질량-스프링 기반 옷감 모델의 애니메이션을 효율적이며 사실적으로 생성하기 위해 근사된 암시적 적분법을 계층적으로 적용하는 기법을 제안한다. 제안된 계층적 시뮬레이션 방법은 매우 많은 정점을 가진 메쉬(mesh)의 사실적인 움직임을 상호작용적으로 생성할 수 있다. 이 기법은 암시적 적분법을 근사하는 빠르고 안정적인 방법을 사용한다. 이 근사 기법은 효율적이기는 하지만 극도로 부정확하며 지나치게 댐핑(damping)이 많이 일어난다. 본 논문에 제안된 계층적 시뮬레이션 기법은 메쉬 구조를 다중 단계로 구성하여 옷감 모델의 사실적인 외형을 표현하도록 하며, 각각의 단계에 시뮬레이션을 적용할 때 현재 단계의 메쉬에 존재하는 일부 질점이 이전 단계의 시뮬레이션 결과를 따르도록 한다. 이러한 계층적 시뮬레이션 방법은 많은 수의 질점으로 구성된 옷감 모델의 사실적인 동작을 효율적으로 생성한다. 또한 계층적 기법은 옷감 모델에 사실적인 주름을 생성할 수 있도록 하며, 계층적 단계에 따라 스프링의 수축 저항을 제어할 수 있도록 하여 주름의 패턴도 쉽게 제어할 수 있도록 한다.

• 한국대기환경학회지
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• 제21권4호
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• pp.439-458
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• 2005

An automated analysis system for water soluble constituents in $PM_{2.5}$ has been developed. The system consists of a high capacity multi tube diffusion scrubber (MTDS), a low temperature particle impactor (LTPI), and two ion (anion and cation) chromatography (IC) systems. Atmospheric particles have been collected by passing sample air through a thermostated MTDS followed by a LTPI. This system allows simultaneous measurements of soluble ions in $PM_{2.5}$ at 30 minutes interval. At the air sampling flow rate of 1.0L/min, the detection limits of the overall system are in the order of tens of $ng/m^3$. This system has been successfully used for the measurement of particulate components of Seoul air from April 2003 to January 2004. $SO_4^{2-},\;NO_3^-,\;NH_4^+,\;NO_2^-,\;Cl^-,\;Na^+,\;K^+,\;Ca^{2+},\;and\;Mg^{2+}$ are the major ionic species for $PM_{2.5}$ at Seoul. Among them, $SO_4^{2-},\;NO_3^-\;and\;NH_4^+$ are the most abundant ions, contributed up to $86\%$ of the total and the concentrations were higher than those in any other urban sites in the world except for Chinese cities. There are high pollutant episodes which contribute about $15\~20\%$ of annual average values of the major ions. During the episode, the all parcels were transported from the asian continent and $PM_{2.5}$ were significantly neutralized. This suggests that aged and long range transported pollutants caused the high pollutant episodes. They showed a distinct daily and seasonal variations:they showed a peak in the early morning caused by the night-time accumulation of particulate matters. Atmospheric reactions including gas-to-particle reactions and inter-particle reactions and meteorological parameters including relative humidity and ambient temperature were described with related to the $PM_{2.5}$ 5 concentrations. All of the ionic species showed higher concentrations during the spring than those for summer and winter.