고속 주축 베어링의 조립공차에 관한 연구

김인찬,이찬홍,정윤교 한국정밀공학회 1994 한국정밀공학회 학술발표대회 논문집 Vol.1994 No.11월

이류 유동장의 초확산과 무작위성

김인찬,Kim, In Chan 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.9

Superdiffusive transport motions of passive scalars are numerically considered for various advection velocity fields. Calculated exponents ${\alpha}$ in the superdiffusion-defining relation ${\sigma}^2(t){\sim}t^{\alpha}$ for model flow fields agree to the theoretically predicted values. Simulation results show that the superdiffusion takes place as the tracers' motion become less random, compared to their motion at the pure molecular diffusion. Whether the flow field is random or not, degrees of superdiffusion are directly related to the velocity autocorrelation functions along the tracers Lagrangian trajectories that characterize degrees of randomness of the tracers' motion.

3차원 체커보드의 전도율과 연결성

김인찬 국립7개대학공동논문집간행위원회 2002 공업기술연구 Vol.2 No.-

We consider the long-standing problem of whether the three-dimensional checkerboard has the connectivity. For this purpose, we first consider the problem of determining the effective conductivity of the heterogeneous medium having the checkerboard geometry by use of the Brownian motion simulation method. Specifically we use the efficient first-passage-time technique. Simulation results show that the effective conductivity of the three-dimensional checkerboard increases faster than the two-dimensional counterpart when the contrast between the phase conductivities increases. This implies that the three-dimensional checkerboard's connectivity is greater than the two-dimensional checkerboard's and thus each phase material of the three-dimensional checkerboard is more likely to be connected than not to be connected.

도전성 플라스틱의 전도 퍼콜레이션

김인찬,Kim, In Chan 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.6

A composite plastic, where long metallic fibers are used as filling materials, is transformed from nonconducting to conducting medium as the volume fraction of filling metallic fibers is increased from zero : such drastic change in property is called the percolation. It is desired both for practical and theoretical purposes to understand the physics underlying the percolation and to estimate the percolation threshold that is defined by the minimum volume fraction of the metallic fibers for which the percolation occurs. In this study, percolation thresholds are calculated by Monte Carlo Computer simulation. Both lattice and continuum spaces are considered and detailed microstructures of metallic fibers are modelled as rigid and flexible bodies for both model spaces. Simulations are carried out for wide range of aspect ratios and discussions are given.

Lattice Boltzmann 유체해석의 몇가지 점착경계 기법의 비교

김인찬 群山大學校 1997 論文集 Vol.24 No.-

No-slip boundary condition is considered with respect to the Lattice Boltzmann fluid simulation. The commonly used bounce-back boundary condition is of the first order in computation error in the sense that the magnitude of error grows linearly as the mesh size increases. This makes the Lattice Boltzmann scheme the first order in error despite that the Lattice Boltzmann equation itself exhibits the second order behavior. Various second order boundary techniques have been proposed as alternatives but their own relative advantages and disadvantages have not been fully explored. The new techniques as well as the conventional bounce-back technique are compared through the application to the two dimensional Couette and Poiseulle flows. As for the computation error, all the methods except for the bounce-back showed the expected second order behaviors. It also turns out that among all tested methods, the so-called shifted bounce-back boundary condition and the method proposed by Inamuro et. al. [Phys. Fluids 7, 2928-2930 (1995)] possess the widest convergence range of parameters. suggesting that these are the most robust methods.

한국군(軍) 장병의 외상 후 스트레스 장애(PTSD)에 대한 국내 동향 연구

김인찬,조상근,김종훈,홍명숙,강성후,박상혁 국제문화기술진흥원 2023 The Journal of the Convergence on Culture Technolo Vol.9 No.1

When a traumatic subject experiences extreme stress, various psychiatric problems, including PTSD, can occur if they do not respond appropriately. In addition, non-war soldiers who experience life-threatening events while serving in the military may experience severe and chronic PTSD symptoms. However, there are still insufficient domestic studies on what traumatic events soldiers are exposed to and how much PTSD symptoms they experience. Therefore, this study provides a method that can be used as basic data for PTSD and psychological support of military service personnel by identifying trends in domestic research. Furthermore, it studies PTSD not only of soldiers but also of 'civilians' who have experienced combat, and provides symptomatic treatment and relief programs to civilians according to the difference in PTSD between general trauma and war trauma. It is expected that these studies will increase military confidence and enable the military to play a leading role in war trauma PTSD research and prevention, treatment and mitigation. 외상을 경험하는 대상자가 극심한 스트레스를 경험할 때 적절히 대처하지 않으면 외상 후 스트레스 장애(Post Traumatic Stress Disorder, PTSD) 등을 포함해 다양한 정신과적 문제가 발생할 수 있다. 또한, 전쟁이 아니더라도 군 복무 중 목숨을 위협하는 사건을 경험한 군인들은 심각하고 만성화된 PTSD 증상을 경험할 수 있음을 고려하면 이에 대한 개입을 위해 장병들이 어떠한 외상사건에 노출되어 있는지, 이로 인한 PTSD 증상을 어느 정도 경험하는지에 대한 연구가 필요하지만, 아직 국내연구가 부족한 실정이다. 따라서 본 연구는 국내 연구의 동향을 파악하고 이를 통해 군 장병의 PTSD와 심리적 지원을 위한 기초자료로 활용될 수 있는 방안을 제공하며 더 나아가 군인뿐만 아니라 전투를 경험한 ‘민간인’의 PTSD에 대해서도 연구하고 일반외상과 전쟁 외상의 PTSD 차이에 따라 증상 치료 및 완화 프로그램을 민간인들에게 제공한다면 대군 신뢰 상승뿐만 아니라 군이 전쟁 외상 PTSD 연구와 예방, 치료 및 완화 분야에서 주도적 역할을 할 수 있을 것이라 기대된다.

미군의 해외파병 장병과 가족 지원정책 연구

김인찬,홍명숙,김종훈,조상근,강성후,박상혁 국제문화기술진흥원 2023 The Journal of the Convergence on Culture Technolo Vol.9 No.2

미군은 제1차 세계대전부터 파병장병과 그 가족에 대한 지원정책을 발전시켜오고 있다. 이러한 미군의 파병장병 및 가족 지원정책은 파병 전‧중‧후 시기별로 구분된다. 파병 전에는 주로 금전문제와 주거문제에 대한 지원이 제공된다. 파병 중에는 장병과 가족의 관계 유지, 자녀의 학업성과 확인 등이 가능하도록 국방부 차원의 커뮤니티가 구성된다. 파병복귀 후에는 장병과 가족의 정신 및 신체건강에 대한 지원이 이루어진다. 본 연구에서는 이를 바탕으로 국방부 해외파병 업무 훈령을 법률로 격상하여 파병장병 가족이 관사에 거주하지 않더라도 주거지원을 받게 할 것, 파병부대와 파병장병 가족 간 파병부대 소식, 육아, 자녀교육 등의 정보를 실시간 공유할 수 커뮤니티를 개설할 것, 일정 기간 동안 파병복귀 장병과 가족의 정신건강을 관리할 것을 제안하고 있다.

학습기대와 지식공유 지각이 사용자 만족과 지속사용에 미치는 영향

김인찬,백승령 한국정보시스템학회 2019 情報시스템硏究 Vol.28 No.4

Purpose The purpose of this study is to investigate the effects of learning expectation and perceived knowledge sharing on user satisfaction and IS continuance in the Korean Army which is currently using the Regiments’ Information System to help their Integrated Administration Management. Based on both the Information System(IS) Continuance Model and IS Success Model, this study also examine the role of system quality on user satisfaction. We develop a research model(structural equation model) and its hypotheses that learning expectation, perceived knowledge sharing, and system quality increase users’ satisfaction, which leads to IS continuance. The effect of learning expectation on perceived knowledge sharing is also hypothesized. Design/methodology/approach Online Survey using e-mails was administered to test our research model and associated hypotheses. Among the 360 e-mail letters including our survey questionnaire, 285 responses were collected via e-mails. Meaningful 225 cases were analyzed for our study. SPSS Statistics 24.0 and SmartPLS 3.0 were used to analyze both measuremant test and hyotheses test by using the data set. Findings Survey results show that learning expectation(confirmation variable), learning expectation, perceived knowledge sharing(a perceived usefulness variable), and system quality(a system characteristic) each increases user satisfaction, which leads to IS continuance, under the control of the effect of habit to use information systems. Learning expectation also has a positive influence on perceived knowledge sharing. Theoretical and practical implications are presented.

체커보드 형상을 가진 3차원 복합소재의 연결도와 전도율

김인찬 대한기계학회 2004 大韓機械學會論文集B Vol.28 No.2

An Efficient Brownian Motion Simulation Method for the Conductivity of a Digitized Composite Medium

김인찬 대한기계학회 2003 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.17 No.4

We use the first-passage-time formulation by Torquato, Kim and Cule [J. Appl. Phys., Vol. 85, pp. 1560∼1571 (1999) ], which makes use of the first-passage region in association with the diffusion tracer's Brownian movement, and develop a new efficient Brownian motion simulation method to compute the effective conductivity of digitized composite media. By using the new method, one can remarkably enhance the speed of the Brownian walkers sampling the medium and thus reduce the computation time. In the new method, we specifically choose the first-passage regions such that they coincide with two, four, or eight digitizing units according to the dimensionality of the composite medium and the local configurations around the Brownian walkers. We first obtain explicit solutions for the relevant first-passage-time equations in two-and three-dimensions. We then apply the new method to solve the illustrative benchmark problem of estimating the effective conductivities of the checkerboard-shaped composite media. for both periodic and random configurations. Simulation results show that the new method can reduce the computation time about by an order of magnitude.