• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2014년도 춘계학술대회
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• pp.258-259
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• 2014

파랑과 해저지반의 상호작용을 규명하기 위해서는 우선 해저면의 경계조건을 고려한 새로운 분산관계식의 도입이 필요하다. 본 연구에서는 깊이가 유한한 해저지반의 투수성 및 변위를 고려한 새로운 분산관계식을 유도하였으며, 해저지반의 두께, 탄성계수, 포화도, 투수계수, 간극률 등 다양한 지반상수의 변화에 따른 파랑 감쇠율을 비교 검토하였다.

• Journal of Korea Trade
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• 제26권4호
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• pp.1-22
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• 2022

Purpose - This paper empirically investigates the effect of a rise in the global value chain (GVC) on the industry-level efficiency of resource allocation (based on plant-level inefficiency measures) in Korea, with a focus on various channels through which a rise in the GVC can increase competition among firms and thus induce resources to be allocated more efficiently across firms. Design/methodology - We empirically investigate the relationship between the industry-specific importance of GVC and the industry-level allocative inefficiency that is measured as the dispersion of the plant-level marginal revenue of capital (MRK) as in Hsieh and Klenow's (2009) influential model. We compute MRK dispersion for industries sorted by various characteristics that are closely related to firm/industry sensitivity to the GVC. In other words, we compute the average industry-level MRK dispersion for industries sorted by industry-specific importance of GVC and compute the difference between the two groups of industries (higher vs. lower than the median GVC); we also calculate the difference between industries sorted by industry-specific export (import) intensity. This is our difference-in-difference estimate of the MRK dispersion associated with the GVC for the export (import)-intensive industry versus the non-export (non-import)-intensive industry. This difference-in-difference estimate of the MRK dispersion conditional vs. unconditional on firm-level productivity is then calculated further (triple-difference estimate). Findings - A rise in GVC is associated with a decrease in the MRK dispersion in the export-intensive industry compared to the non-export-intensive industry. The same is true for industries that rely heavily on imports versus those that do not (i.e., import intensive vs. non-intensive). Furthermore, the reduction in the MRK dispersion in the export-intensive industry associated with an increase in the GVC is disproportionately greater for high-productivity firms. In contrast, the negative relationship between GVC and MRK dispersion in the import-intensive industry is disproportionately smaller for high-productivity firms. Originality/value - Existing studies focus on the relationship between GVC and aggregate output, exports, and imports at the country level. We investigate detailed firm/industry-level mechanisms that determine the relationship between GVC, trade, and productivity. Using the plant-level data in South Korea, we investigate how GVC is related to the cross-firm MRK dispersion, an important measure of allocative inefficiency, based on Hsieh and Klenow's (2009) influential economic theory. This is the first study to provide plant-level evidence of how GVC affects MRK dispersion. Furthermore, we examine how the relationship between GVC and MRK-dispersion varies across export intensity, import intensity, and firm-level productivity, providing insight into how GVC can affect firms' exposure to competition in the global market differently depending on market conditions and thus generate trade-related productivity gains.

• 정보학연구
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• 제1권2호
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• pp.1-14
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• 1998

본고에서는 노동조합운동과 임금, 그리고 임금분산도가 동시에 결정되는 분석모형을 이용하여 임금분산도에 대한 노동조합의 효과뿐만 아니라 노조 조직결성에 대한 임금분산도의 효과를 실증 분석한 것이다. 노조의 산업내 임금평준화효과는 통계적으로 유의미하였고, 노조 조직률이 1% 상승함에 따라 임금분산이 0.05%-0.11% 축소되는 것으로 나타났다. 임금분산이 노조의 조직결성에 미치는 효과는 통계적 유의성이 없어 노조 조직률에 대한 임금분산의 효과는 발견할 수 없었다.

• 한국산학기술학회논문지
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• 제18권11호
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• pp.409-415
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• 2017

본 논문은 보상 격차가 노동 생산성에 미치는 영향을 토너먼트 신규 인력 유입과 토너먼트 내 잔류자의 방출 효과를 중심으로 살펴본다. 보상 격차의 긍정적 효과를 설명하는 주요 이론인 토너먼트 이론에 따르면, 조직 내 보상 격차 확대는 외부의 우수 인력을 유인하고 내부의 저성과자들을 자연스럽게 퇴출함으로써 조직성과 향상에 기여하게 된다. 이러한 주장에도 불구하고 그간 토너먼트 이론을 중심으로 한 보상 격차 논의에서는 토너먼트의 참가자 측면이 간과되어 왔는데, 이에 본 연구에서는 토너먼트에 새롭게 유입되는 외부 인력 채용과 기존 토너먼트에서 잔류하는 인력에 대한 방출이 보상 격차와 노동생산성 간 관계에 어떠한 영향을 주는지를 살펴보았다. 이에 본 논문에서는 보상 격차 자체는 노동생산성에 정(+)의 효과를 가질 것으로 예측하였으며, 신규 인력 유입은 보상 격차와 노동생산성 간 정(+)의 관계를 약화시키는 반면, 잔류자의 방출 효과는 이러한 정(+)의 관계를 강화시킬 것으로 가설화하였다. 132개 기업 데이터를 통해 실증 분석한 결과, 보상 격차는 노동생산성 증가에 기여하였으며, 외부 신규 인력 유입은 보상 격차와 노동생산성 간 정(+)의 관계를 약화시키는 것으로 나타났다. 반면, 잔류자의 방출의 경우 예측과는 달리 오히려 보상 격차와 노동생산성 간 정(+)의 관계를 약화시키는 결과를 보였다. 이러한 이론적 논의와 실증 결과는 보상 격차 도입에 있어 토너먼트 내에서 우수 신규 인력의 유입과 잔류자의 방출이라는 조건이 갖추어져야 함을 보여준다.

• Journal of Chest Surgery
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• 제41권4호
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• pp.439-446
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• 2008

배경: 본 연구의 목적은 좌심실 수축기능, 용적, 질량과 QT dispersion간의 관계를 알아보고, 관상동맥 협착이 있는 환자와 없는 환자에서 비교하는 것이다. 대상 및 방법: 174명의 ST분절 및 심근효소 이상소견이 없는 전형적인 안정성 협심증을 호소하는 환자들을 대상으로 하였다. Group I은 심혈관 촬영상 관상동맥 협착이 50%이상(n=101), Group II는 심혈관 촬영상 관상동맥 협착이 50%이하(n=73)인 환자로 나누었다. 심혈관 촬영 전에 좌심실 구출율, 용적, 질량을 심초음파로 측정하였고 QT dispersion측정을 위해 12-lead 심전도를 측정하였다. 결과: QT dispersion은 Group I에서 Group II보다 유의하게 길었다(39.8 ms vs. 33.3 ms; p<0.05). 모든 환자에서 좌심실용적, 질량은 QT dispersion과 통계학적으로 유의한 상관관계가 있었으며, 좌심실 질량은 유일한 독립적 관계요소였다.(p<0.05). 그런데 Group I에서만 보면 초음파상에 나타난 어떤 결과도 QT dispersion과 유의한 상관 관계가 없었으며, Group II에서는 좌심실 용적, 질량은 QT dispersion과 유의한 상관관계가 있었으며, 좌심실 질량은 여전히 독립적 관계 요소였다(p<0.05). 결론: 우리의 연구는 좌심실용적, 질량 등은 안정성 협심증환자에서 QT dispersion과 유의한 상관관계를 나타냈다. 이런 소견들은 저명한 관상동맥 협착이 없는 환자들에서만 나타난다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.89-92
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• 2001

This study aims at investigating the relationship between dispersion coefficient ratio to molecular diffusion coefficient (D$_{l}$ /D$_{m}$) and Peclet number (Pe) for multi-solute system in non-Darcian flow regime. Existing understanding on solute dispersion is primarily derived from one-solute system in Darcian flow regime. We found that solute dispersion in rock fractures can be characterized by the mechanism of both macrodispersion and Taylor dispersion, even for non-Darcian f]ow domain. For the Darcian flow regime even different solutes lead to the same D$_{l}$ /D$_{m}$ at same Pe. However, as the flow becomes non-Darcian, solute with a higher molecular diffusion coefficient result in higher D$_{l}$ /D$_{m}$ at tile same Pe than that with a lower diffusion coefficient.cient.

• 한국항해항만학회지
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• 제41권5호
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• pp.345-352
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• 2017

Recently, a new port reserves deep water depth for safe navigation and mooring, following the trend of larger ship building. Larger port facilities include long and huge breakwaters, and mainly adopt vertical type considering low construction cost. A vertical breakwater creates stem waves combining inclined incident waves and reflected waves, and this causes maneuvering difficulty to the passing vessels, and erosion of shoreline with additional damages to berthing facilities. Thus, in this study, the researchers have investigated the response of stem waves at the vertical breakwater near the entrance channel and applied numerical models, which are commonly used for the analysis of wave response at the harbor design. The basic equation composing models here adopted both the linear parabolic approximation adding the nonlinear dispersion relationship and nonlinear parabolic approximation adding a linear dispersion relationship. To analyze the applicability of both models, the research compared the numerical results with the existing hydraulic model results. The gap of serial breakwaters and aligned angles caused more complicated stem wave generation and secondary stem wave was found through the breakwater gap. Those analyzed results should be applied to ship handling simulation studies at the approaching channels, along with the mooring test.

• 한국대기환경학회지
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• 제16권3호
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• pp.237-246
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• 2000

An experimental study has been carried out using a rotating water channel in order to investigate the effect of surface roughness on the vertical dispersion of plume within boundary layer. Dispersion measurements of tracers released from two sources with different height at neutral conditions over various rough terrain ranging from rural to urban have been performed. Various values of roughness length were simulated by combining of 4 stream velocities and 3 roughness element conditions. Dispersion measurements have also been made for rough terrain where high buildings are locally concentrated. Values of $\sigma$z increase with roughness and this tendency appears to apply both cases of with and without locally concentrated high buildings. The comparisons of the Bowne's nomogram on $\sigma$2 vs x relationship and the measurements of $\sigma$2 with roughness show good accordance in $\sigma$2 distribution at stability D class over rural, suburban and urban terrain. For constant roughness length the $\sigma$2 values of plumes from lower source height are smaller than those of plumes from higher source at short downwind distance, but this relationship becomes reverse as distance increases. Crossing appears to be made before about 2km. The value of constant I in McMullen's equation $\sigma$2=exp [I+J(In x) + K(In x)2] appears to increase with roughness length, however, the relationships between other constants and roughness have been confirmed. The values of $\sigma$2 for various downwind distances, estimated by using an equation which is employed in ISC (Industrial Source Complex) dispersion model for areas where high buildings are locally assembled, are in accordance with measurements from water channel experiments.

• 한국입자에어로졸학회지
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• 제13권3호
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• pp.133-139
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• 2017

In this paper, we proposed an emulsification method without using an emulsifier and investigated the effects of particle size distribution in fluids on dispersion stability. Surfactant-free oil in water emulsion was prepared with 1 % (w/w) of olive oil by using high speed agitation, high pressure and ultrasonic dispersion methods. The particle size, microscopic observation, and dispersion stability of each sample were evaluated and dispersion stability according to various dispersion methods was compared. As a result, the emulsion dispersed by the ultrasonic dispersion method showed the smallest particle size and uniform distribution of $0.07{\sim} 0.3{\mu}m$ and was the most stable in a 7 days stability evaluation. In the above experiment, four olive oil emulsions having different particle sizes were prepared using ultrasonic dispersion technology that was capable of producing stable emulsions. The dispersion stability of each samples with oil droplet sizes of (A) 0.1 to $0.5{\mu}m$, (B) 0.3 to $4{\mu}m$, (C) 1 to $10.5{\mu}m$ and (D) 2 to $120{\mu}m$, was observed for 7 days, and the relationship between the stability and performance was studied. Emulsion (A) with particle size less than $0.5{\mu}m$ displayed the dispersion stability showing below 5 % change in a 7 days stability evaluation. In the case of (B), (C), and (D) that had larger particle than $0.5{\mu}m$, the changes of dispersion stability were 10 %, 13 % and 35 % respectively. From these results, it was proved that dispersion stability of emulsion with uniform particle size of $0.5{\mu}m$ or less was confirmed to be very stable.

• 노동경제논집
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• 제34권2호
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• pp.29-52
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• 2011

본고는 1990년대 후반 이후 한국기업에 급속히 도입되어 온 연봉제가 실제로 성과에 따른 임금격차를 가져왔는지에 대하여 분석하였다. 노동부 "임금구조기본통계조사" 1996년부터 2006년까지 100인 이상 기업 대졸 사무직에 대한 자료를 활용하였고, 기업내 임금격차 변수로는 개인 속성에 대한 영향을 배제할 수 있도록 임금함수를 추정하고 잔차의 분산을 기업수준의 변수로 활용하여 분석하였다. 분석 결과, 연봉제의 도입은 기업내 임금격차를 확대시키는 것으로 나타났다. 그러나 연봉제 적용 비중과 임금격차 간의 관계는 비선형관계($\bigcap$)임을 시사하는 결과가 나타났다.