• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 춘계학술대회논문집
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• pp.368-376
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• 2009

Studies on the effect of the wall-ion, wall-water, water-ion and ion-ion interaction on properties of water and ions in nano-channels have been performed through the use of different kinds of ions or different models of potential energy between wall-ion or wall-water. On this paper, we address the effect of water-wall interaction potential on the properties of confined aqueous solution by using the molecular dynamics (MD) simulations. As the interaction potential energies between water and wall we employed the models of the Weeks-Chandler-Andersen (WCA) and Lennard-Jones (LJ). On the MD simulations, 680 water molecules and 20 ions are included between uniformly charged plates that are separated by 2.6 nm. The water molecules are modeled by using the rigid SPC/E model (simple point charge/Extended) and the ions by the charged Lennard-Jones particle model. We compared the results obtained by using WCA potential with those by LJ potential. We also compared the results (e.g. ion density and electro-static potential distributions) in each of the above cases with those provided by solving the Poisson-Boltzmann equation.

• 산업경영시스템학회지
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• 제14권24호
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• pp.15-21
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• 1991

Jones [11], [12]developed a measurement method of the economic depreciation by infinite-horizen linear program model. This paper models an economic depreciation schedule in constant price based on the infinite-horizen LP. And the appropriate application of the maintenance/operating cost, the discount rate, the taxation and the price fluctuation in the model was suggested.

• Bulletin of the Korean Chemical Society
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• 제2권1호
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• pp.17-24
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• 1981

Thermodynamic properties such as sublimation pressures, enthalpies and entropies of sublimation, enthalpies and entropies of solid krypton and xenon are calculated from $0{\circ}K$ to the triple point, using the vacancies-in-solid model. The Mie-Lennard-Jones 12,6 potential in uniform potential field is used. The results are compared with the calorimetric and sublimation pressure values, and are in a good agreement with the available calorimetric and sublimation pressure values.

• Advances in Computational Design
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• 제5권4호
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• pp.417-443
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• 2020

Tunnels have been an integral part of human civilization. Due to complexity in its design and structure, the stability of underground structures under extreme loading conditions has utmost importance. Increased terrorism and geo-political conflicts have forced the engineers and researchers to study the response of underground structures, especially tunnels under blast loading. The present study has been carried out to seek the response of tunnel structures under blast load using the finite element technique. The tunnel has been considered in quartzite rock of northern India. The Mohr-Coulomb constitutive model has been adopted for the elastoplastic behaviour of rock. The rock model surrounding the tunnel has dimensions of 30 m x 30 m x 35 m. Both unlined and lined (concrete) tunnel has been studied. Concrete Damage Plasticity model has been considered for the concrete lining. Four different parameters (i.e., tunnel diameter, liners thickness, overburden depth and mass of explosive) have been varied to observe the behaviour under different condition. To carry out blast analysis, Coupled-Eulerian-Lagrangian (CEL) modelling has been adopted for modelling of TNT (Trinitrotoluene) and enclosed air. JWL (Jones-Wilkins-Lee) model has been considered for TNT explosive modelling. The paper concludes that deformations in lined tunnels follow a logarithmic pattern while in unlined tunnels an exponential pattern has been observed. The stability of the tunnel has increased with an increase in overburden depth in both lined and unlined tunnels. Furthermore, the tunnel lining thickness also has a significant effect on the stability of the tunnel, but in smaller diameter tunnel, the increase in tunnel lining thickness has not much significance. The deformations in the rock tunnel have been decreased with an increase in the diameter of the tunnel.

• 반도체디스플레이기술학회지
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• 제9권1호
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• pp.5-10
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• 2010

Among a variety of cleaning processes, the cryogenic carbon dioxide ($CO_2$) cleaning has merits because it is highly efficient in removing very fine particles, innoxious to humans and does not produce residuals after the cleaning, which enables us to extend its area of coverage in the semi-conductor fabrication society. However, the cryogenic carbon dioxide cleaning method has some technical research issues in aspect to particles' adhesion and removal. To resolve these issues, performing an analysis for the identification of particle adhesion mechanism is needed. In this study, a research was performed by a theoretical approach. To this end, we extended the G-T (Greenwood-Tripp) model by applying the JKR (Johnson-Kendall-Roberts) and Lennard-Jones potential theories and the statistical characteristics of rough surface to investigate and identify the contact, adhesion and deformation mechanisms of soft or hard particles on the rough substrate. The statistical characteristics of the rough surface were taken into account through the employment of the normal probability distribution function of the asperity peaks on the substrate surface. The effects of surface roughness on the pull-off force for these particles were examined and discussed.

• Journal of the Korean Data and Information Science Society
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• 제20권1호
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• pp.1-9
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• 2009

회귀모형의 분산함수가 알려져 있지 않은 한 점에서 불연속이라 가정하자. Yu와 Jones (2004)는 음이 아닌 값을 취하는 분산함수를 실수 값을 취하도록 하기 위하여 로그 변환하였고, 변환된 로그분산함수를 국소다항적합으로 추정하였다. 로그분산함수의 국소다항적합을 이용하여, Huh (2008)는 분산함수의 불연속점의 추정하는 대신 로그분산함수의 불연속점을 추정하였다. 본 연구는 Huh의 점프의 크기 추정량의 점근분포를 이용하여 로그분산함수의 불연속점의 존재여부에 대한 가설검정을 제안하고, 제안한 방법에 대한 모의실험 결과를 제시하고자 한다.

• Korea-Australia Rheology Journal
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• 제18권3호
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• pp.161-167
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• 2006

This study presents results on the numerical simulation of Newtonian and non-Newtonian flow in a channel obstructed by an asymmetric array of obstacles for clarifying the descriptive ability of current non-Newtonian constitutive equations. Jones and Walters (1989) have performed the corresponding experiment that clearly demonstrates the characteristic difference among the flow patterns of the various liquids. In order to appropriately account for flow properties, the Navier-Stokes, the Carreau viscous and the Leonov equations are employed for Newtonian, shear thinning and extension hardening liquids, respectively. Making use of the tensor-logarithmic formulation of the Leonov model in the computational scheme, we have obtained stable solutions up to relatively high Deborah numbers. The peculiar characteristics of the non-Newtonian liquids such as shear thinning and extension hardening seem to be properly illustrated by the flow modeling. In our opinion, the results show the possibility of current constitutive modeling to appropriately describe non-Newtonian flow phenomena at least qualitatively, even though the model parameters specified for the current computation do not precisely represent material characteristics.

• Journal of the korean society of oceanography
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• 제39권4호
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• pp.222-233
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• 2004

Using nitrogen as the limiting nutrient, the default version of a microplankton-detritus model linked chlorophyll concentration to the autotroph nitrogen. However, phosphorus dynamics were added to simulate the results of a microcosm experiment. Using standard parameter values with a single value of microheterotroph fraction in the microplankton taken from the observed range, the best simulation successfully captured the main features of the time-courses of chlorophyll and particulate organic carbon, nitrogen and phosphorus, with root-mean-square error equivalent to 29% of particulate concentration. A standard version of microbiological model assumes complete internal cycling of nutrient elements; adding a term for ammonium and phosphate excretion by microheterotrophs did not significantly improve predictions. Relaxing the requirement for constant microheterotroph fraction resulted in an autotroph-heterotroph model AH, with dynamics resembling those of a Lotka-Volterra predator-prey system. AH fitted the microcosm data worse than did MP, justifying the suppression of Lotka-Volterra dynamics in MP. The paper concludes with a discussion of possible reasons for the success of the simple bulk dynamics of MP in simulating microplankton behaviour.

• 정보학연구
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• 제1권2호
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• pp.209-227
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• 1998

본 연구는 회계이익을 구성요소별로 분리시켜 회계이익과 주가수익률간의 관계에서 영업현금흐름, 재량적 발생액, 비재량적 발생액, 및 비재량적 이익이 회계이익에 대해 추가적 정보효과를 제공하는지 여부를 한국자본시장의 자료를 이용하여 실증적으로 검증한다. 이를 위해 회계이익을 영업현금흐름과 총발생액으로 구분하고, 다시 총발생액을 재량적 발생액과 비재량적 발생액으로 분리시켜, 종속변수를 초과수익률로 하고 독립변수에 각 회계이익의 구성요소들을 포함시키는 회귀분석방법으로 검증하였다. 표본기업은 1984년부터 1995년까지 연속된 자료를 이용할 수 있는 158개 기업을 대상으로 하였고, 1984년부터 1993년(10년간 통합된 1,580개 자료)까지는 비재량적 발생액의 추정기간으로 삼아 Jones모형(1991)을 이용한 산업-연도별 횡단면 회귀분석모형으로 추정한 다음에 1994, 1993년(2년간 통합된 316개 자료)을 검증기간으로 하여 총 발생액을 재량적 발생액과 비재량적 발생액으로 분리시키는 방법을 사용하였다. 연구곁과에 의하면, 회계이익의 구성요소들을 독립변수로 하고 주가수익률을 종속변수로 하는 다중회귀분석에서는 회계이익에 대해 영업현금흐름과 재량적 발생액은 추가적 정보가치가 있는 것으로 나타났다. 이는 재량적 발생액이 기업성과측정가설과 일치하는 것으로 해석 할 수 있다. 또한 회계이익에 대해 비재량적 이익과 재량적 발생액도 추가적 정보가치가 있는 것으로 나타났다. 그리고 추가분석결과에서는 비재량적 발생액의 절대값의 크기가 큰 집단에서 유의한 양의 더미변수가 검증되었는데, 이는 비재량적 발생액의 절대적 크기가 클수록, 회계이익과 영업현금흐름에 대해서 순기능적인 추가적 정보력을 제공하는 것으로 여겨진다.

• 정보학연구
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• 제7권3호
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• pp.19-36
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• 2004

본 연구에서는 회계이익을 구성요소별로 분리시켜 회계이익과 주가수익률간의 관계에서 영업현금흐름, 재량적 발생액, 비재량적 발생액, 및 비재량적 이익이 회계이익에 대해 추가적 정보효과를 제공하는지 여부를 한국자본시장의 자료를 이용하여 실증적으로 검증하였다. 이를 위해 회계이익을 영업현금흐름과 총발생액으로 구분하고, 다시 총발생액을 재량적 발생액과 비재량적 발생액으로 분리시켜, 종속변수를 초과수익률로 하고 독립변수에 각 회계이익의 구성요소들을 포함시키는 회귀분석방법으로 검증하였다. 표본기업은 1991년부터 2003년까지 연속된 자료를 이용할 수 있는 156개 기업을 대상으로 하였고, 1991년부터 2001년(10년간 통합된 1,580개 자료)까지는 비재량적 발생액의 추정기간으로 삼아 Jones모형(1991)을 이용한 산업-연도별 횡단면 회귀분석모형으로 추정한 다음에 2002, 2003년(2년간 통합된 316개 자료)을 검증기간으로 하여 총발생액을 재량적 발생액과 비재량적 발생액으로 분리시키는 방법을 사용하였다. 연구결과에 의하면, 회계이익의 구성요소들을 독립변수로 하고 주가수익률을 종속변수로 하는 다중회귀분석에서는 회계이익에 대해 영업현금흐름과 재량적 발생액은 추가적 정보가치가 있는 것으로 나타났다. 이는 재량적 발생액이 기업성과측정가설과 일치하는 것으로 해석할 수 있다. 또한 회계이익에 대해 비재량적 이익과 재량적 발생액도 추가적 정보가치가 있는 것으로 나타났다. 그리고 추가분석결과에서는 비재량적 발생액의 절대값의 크기가 큰 집단에서 유의한 양의 더미변수가 검증되었는데, 이는 비재량적 발생액의 절대적 크기가 클수록, 회계이익과 영업현금흐름에 대해서 순기능적인 추가 정보력을 제공하는 것을 나타낸다.