• Journal of the Korea Computer Graphics Society
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• v.23 no.2
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• pp.29-39
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• 2017

This paper presents a unified framework to efficiently and realistically simulate surface and wave foams. The framework is designed to first project 3D water particles from an underlying water solver onto 2D screen space in order to reduce the computational complexity of determining where foam particles should be generated. Because foam effects are often created primarily in fast and complicated water flows, we analyze the acceleration and curvature values to identify the areas exhibiting such flow patterns. Foam particles are emitted from the identified areas in 3D space, and each foam particle is advected according to its type, which is classified on the basis of velocity, thereby capturing the essential characteristics of foam wave motions. We improve the realism of the resulting foam by classifying it into two types: surface foam and wave foam. Wave foam is characterized by the sharp wave patterns of torrential flow s, and surface foam is characterized by a cloudy foam shape even in water with reduced motion. Based on these features, we propose a technique to correct the velocity and position of a foam particle. In addition, we propose a kernel technique using the screen space density to efficiently reduce redundant foam particles, resulting in improved overall memory efficiency without loss of visual detail in terms of foam effects. Experiments convincingly demonstrate that the proposed approach is efficient and easy to use while delivering high-quality results.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.11
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• pp.1625-1632
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• 2009

This study investigated consumer awareness on imported food safety management. The questionnaire explored status for confirmation as imported foods, consideration factors when imported foods were marketed, ways for finding imported food safety information, people responsible for problems in imported foods safety management, and imported food safety management items. Answers to 1065 questionnaires were analyzed using S-Plus 8.0. The principal results were as follows: 35.7% of respondents always confirmed whether it was imported food. The most important imported foods marketed is children food. 55.1% of respondents think inspectors have responsibility for problems of imported foods safety management. The most important factor for improvement of safety is reinforcement of quarantine. The providing of restricted information only after security problem occurs was the reason for non-satisfaction of safety information.

• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.362-369
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• 2005

Readability, an indicator measuring the easiness of reading letters, is an important element that determines the communicative effectiveness of self-guided signs. This study examined how the letter design elements of self-guided signs influence on readability to provide basic information for more effective sign designs. Data were collected from August to November of 2003 at a self-guided trail of Naejangsan National Park, Korea. A total of 375 subjects participated in the questionnaire survey, and 94.7% of them were used for data analysis. Among the total of 19 attributes, five attributes such as number of letters, number of type styles, ratio of picture area on the signs, space between letters, type size influenced on readability. These five attributes explained 50.0% of the variation in readability. The number of letters was the most influential attributes on readability, followed by the number of type styles, ratio of picture area on the signs, space between letters, and type size. The effectiveness of signs may be efficiently increased by managing these five major attributes with more concern.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.296-296
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• 2008

국내 절토비탈면은 이상 기후 및 건설공사의 증대로 인해 증가하고 있는 추세이며 장마철 및 태풍으로 인해 비탈면의 붕괴로 많은 인명 및 재산피해가 발생되고 있는 실정이다. 국내에서 사용되고 있는 기존의 비탈면의 설계기준은 암반의 불연속면에 대한 조사를 실시하고는 있지만 주로 암반의 굴착난이도를 토층, 리핑암, 발파암으로 구분하여 각각의 비탈면 절취경사를 결정하여 사용하는 방법을 사용하였으며 이러한 기준은 단순히 암석의 강도를 기준으로 설정되어 있으므로 암석의 공학적 특성 즉, 암반내 불연속면 방향성, 연속성, 충진물질, 마찰각, 풍화속도 등의 영향으로 공용후 비탈면 구배의 재조정 및 보강이 빈번하다. 국내외 절토비탈면의 설계기준은 각 기관별로 산재되어 있었으며 비탈면에 대한 설계 및 시공 등에 관한 기준은 도로와 철도 설계기준에 일부 반영되어 있을 뿐 항만, 댐, 택지조성 등 기타 시설 설계기준에는 비탈면에 대한 기준이 마련되어 있지 않아 표준적인 비탈면 설계기준 및 유지관리지침이 등이 필요하였다. 이러한 문제점을 보완하기 위해 2004년부터 2006까지 한국시설안전공단, 한국도로공사, 대한주택공사가 협동으로 연구한 건설공사 비탈면 설계 시공 및 유지관리에 관한 연구의 결과로 2006년도에 "건설공사 비탈면 설계기준"이 수립되었다. 이 설계기준은 건설공사에서의 기존 상이한 기준들을 정리하고 동일화하는 작업을 수행하였으며 지반의 조사에서부터 대책공까지를 막나하여 정리하였다. 그러나 최근에 급격한 기후변화로 인한 비탈면붕괴 빈번함에 따라 과거 적용되어 왔던 이들 기준을 적용하는 경우, 특히 상부 토층 및 풍화암 구간에서 많은 설계안전율을 만족하지 못해 많은 보강을 수반해야 하는 문제가 발생되고 있어 그 원인에 대한 분석을 수행하고자 하였다. 2006년도 정리된 기준은 과거에 적용하여 온 유기시의 안전율 조건을 Fs > 1.1~1.2을 적용하였던 것을 Fs > 1.2로 통일하였으며 지하수위 조건은 지표면에 위치하도록 하였다. 지하수위 조건은 풍화암 및 토층의 경우, 과거 지표면에 -3m를 적용한 시기가 있었으나 지표면에 지하수위를 적용하는 것이 일반적인 해석방법이다. 이러한 결과의 원인을 검토해 보면 다음과 같다. 첫째, 풍화암 및 토층에 적용되어 온 지반강도 정수가 과거 적용한 값보다 최근에는 작아지는 경향을 보이고 있다. 둘째, 지하수위 적용문제로 현재 지표면에 지하수위를 두어 안전율을 감소시키는 문제로 이는 최근 들어 많은 연구기관에서 강우시 간극수압의 증가에 대한 연구가 활발하게 진행되고 있다. 그러나 침투수 해석은 현행 기준에도 강우의 침투를 고려한 해석을 실시하는 경우 FS > 1.3 적용하는 것으로 되어 있으나 대부분의 해석에서는 적용이 되지 못하고 있는 실정이다. 셋째, 안전율이 과거에 주로 적용된 Fs > 1.1에서 Fs > 1.2로 상향 조정되어 우기시의 설계안전율 만족시키지 못하는 문제이다. 그러므로 이러한 문제점을 개선하기 위한 검토가 필요하며 장기적으로 이에 대한 합리적인 기준을 개정하는 작업이 추후에 수행되어야 할 것으로 판단된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.184-187
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• 2013

The Four Major Rivers Restoration Project of is the multi-purpose green growth project in South Korea. Some of the project was progressed by K-water and was declared complete on October 21, 2011. The Four Rivers Restoration Project of Korea was designed to be a packaged project that aims to resolve water-related problems such as floods and droughts and revitalize Korean public spaces near the water. K-water have applied the latest ICT(Information and Communication Technology) for the operating management of 4 Rivers Project facilities. We also have applied ICT for integrating drinking water production facilities. Applying these ICT, we have many experience for integrated water resources management, so we proposed. The first is that the big data collected should be analyzed for making decisions and taking actions while considering multiple viewpoints of how water should be managed. The second is that the new MMI(Man Machine Interface) program should be developed to use domestic needs and promote ease of maintenance for the integrated operation. The third is that the standardization of communication protocol is needed for seamless communication between equipments.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.5
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• pp.215-226
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• 2018

In this paper, to estimate the dynamic behavior of a submerged floating tunnel(SFT) by underwater explosion(UE), the SFT is modeled and analyzed by the explicit structural analysis package LS-DYNA. The section of SFT near to explosion point is modeled to shell and solid elements using elasto-plasticity material model for concrete tubular section and steel lining. And the other parts of the SFT are modeled to elastic beam elements. Also, mooring lines are modeled as tension-only cable elements. Total mass of SFT is including an added mass by hydrodynamic effect. The buoyancy on the SFT is considered in its initial condition using a dynamic relaxation method. The accuracy and the feasibility of the analysis model aree verified by the results of series of free field analysis for UE. And buoyancy ratio(B/W) of SFT, the distance between SFT and an explosion point and the arrangement of mooring line aree considered as main parameters of the explosion analysis. As results of the explosion analysis, the dynamic responses such as the dent deformation by the shock pressure are responded less as more distance between SFT and an explosion point. However, the mooring angle of the diagonal mooring system can not affect the responses such as the horizontal displacement of SFT by the shock pressure.

• Management & Information Systems Review
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• v.36 no.3
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• pp.255-268
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• 2017

This study examines whether firms with tax avoidance of Corporate Social Responsibility(CSR) performance is tempered by the extent firms engage in CEO turnovers. Considering the increasing interest in CSR activities of the firm to secure sustainable growth of national economy, this paper investigates the benefit and cost of CSR activities by combining the agency theory using the firm level data. Prior studies document that investors positively value tax avoidance. The rationale for this finding is that tax avoidance provides cash savings that can be used by firm managers to generate future shareholder wealth. Prior studies also show that investors' valuations are sensitive to the risk of future negative tax outcomes. Assuming that many types of CSR performances are low risk, low yielding uses of firm resources, we posit that higher levels of CSR performance may signal to investors that cash generated via tax avoidance has not been fully used to generate a return sufficient to offset the risk associated with aggressive tax planning strategies. Consistent with this argument, we predict and find that the positive association between CSR performance and tax avoidance is significantly weakened when firms have higher positive levels of CEO turnovers. Further, we predict and find that 'philanthropic' types of CSR activities in particular are associated with investor discounting of tax avoidance. We interpret our results as suggesting the equity market views CSR activities to be ostensibly funded through cash savings generated via tax avoidance.

• Korean Journal of Environment and Ecology
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• v.17 no.3
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• pp.285-294
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• 2003

The purpose of this paper is to provide useful knowledge for recreation management in natural park(NP) by evaluating use suitability of recreation resource. We had obtained data through a questionnaire, which surveyed 385 visitors at 6 of the 73 NP in Korea in 2001, based on stratified sampling method. We have analyzed the data using the multiple regression method. We found that 1) in bivariate analysis, the relationships between use suitability and all the recreation resources are fairly high and statistically significant. The higher the degree of recreation resources, the higher the degree of use suitability. 2) in multivariate analysis, topography, social resource(SR), cultural resource(CR), landscape, smell, color and sound(SCS) have been turned out to be statistically significant at one percent level. 3) the direction of relationship between topography, SR, CR, landscape, SCS and use suitability is same. 4) in relative contribution of the use suitability of recreation resource, level of topography has been turned out to have about 1.05, 1.56, 2.16 and 2.70 times more important than that of SCS, SR, landscape, topography, respectively This results will be used for a criterion for recreation resource evaluation and a settlement of management priority and increasing user's satisfaction.

• Journal of the Korean Magnetics Society
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• v.16 no.6
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• pp.287-292
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• 2006

Al substituted $CoAl_{0.5}Fe_{1.5}O_{4}$ has been studied with x-ray and neutron diffraction, $M\"{o}ssbauer$ spectroscopy and magnetization measurements. $CoAl_{0.5}Fe_{1.5}O_{4}$ revealed a cubic spinel structure of ferrinmagnetic long range ordering at room temperature, with magnetic moments of $Fe^{3+}(A)(-2.29{\mu}_{B}),\;Fe^{3+}(B)(3.81\;{\mu}_{B}),\;Co^{2+}(B)(2.66{\mu}_{B})$, respectively. The temperature dependence of the magnetic hyperfine field in $^{57}Fe$ nuclei at the tetrahedral (A) and octahedral (B) sites was analyzed based on the $N\'{e}el$ theory of magnetism. In the sample of $CoAl_{0.5}Fe_{1.5}O_{4}$, the interaction A-B interaction and intrasublattice A-A superexchange interaction were antiferromagnetic with strengths of $J_{A-B}=-19.3{\pm}0.2k_{B}\;and\;J_{A-A}=-21.6{\pm}0.2k_{B}$, respectively, while the intrasublattice B-B superexchange interaction was found to be ferromagnetic with a strength of $J_{B-B}=3.8{\pm}0.2k_{B}$.

• Journal of the Korean Magnetics Society
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• v.19 no.3
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• pp.113-119
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• 2009

$^{57}Fe_xCu_{1-x}O$(x = 0.0, 0.02) powders were prepared by sol-gel method and their crystallographic and magnetic hyperfine properties have been studied using X-ray diffraction and $M{\ddot{o}}ssbauer$ spectroscopy (MS). The crystal structure of the samples is found to be monoclinic without any secondary phases and their lattice parameters increase with increasing annealing temperature ($T_A$), which is attributed to an increase in oxygen-vacancy content. MS measurements at room temperature indicate that $Fe^{3+}$ ions substitute $Cu^{2+}$ sites and ferromagnetic phase grow with increasing $T_A$. Magnetic hyperfine and quadrupole interactions of $^{57}Fe_{0.02}Cu_{0.98}O$ ($T_A=500^{\circ}C$) in the antiferromagnetic state at 17 K have been studied, yielding the following results: $H_{hf}=426.94\;kOe$, ${\Delta}E_Q=-3.67\;mm/s$, I.S.=0.32 mm/s, ${\theta}=65^{\circ}$, ${\phi}=0^{\circ}$, and ${\eta}=0.6$.