• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.11
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• pp.1785-1795
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• 2001

A multi-layered brick element fur the finite element method is developed for analyzing the three-dim-ensionally layered composite structures subjected to both thermal and mechanical boundary conditions. The element has eight nodes with one degree of freedom for the temperature and three for the display-ements at each node, and can contain arbitrary number of layers with different material properties with-in the element; the conventional element should contain one material within an element. Thus the total number of nodes and elements, which are needed to analyze the multi-layered composite structures, can be tremendously reduced. In solving the global equation, a partitioning technique is used to obtain the temperature and the displacements which are caused by both the mechanical boundary conditions and temperature distributions. The results by using the developed element are compared wish the commercial package, ANSYS and the conventional finite element methods, and they are in good agreement. It is also shown that the Number of nodes and elements can be tremendously reduced using the element without losing the numerical accuracies.

• The Journal of the Acoustical Society of Korea
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• v.27 no.7
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• pp.365-371
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• 2008

In this study, beat control method using an equivalent ring model is proposed to control beat period of a slightly asymmetric ring. Slight asymmetry in a ring generates mode pair and the interaction of the mode pair makes beat in vibration and sound. In a ring, as a simplified bell type structure, mode data are measured and an equivalent ring is determined so that the measured mode condition is satisfied. By the finite element analysis on the equivalent ring, changes of mode pair condition are predicted when local mass is attached or the local thickness is decreased. The predicted results are compared with the experimental result and the validity of the proposed method is verified.

• The Korean Society of Law and Medicine
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• v.19 no.1
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• pp.207-254
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• 2018

The major court rulings delivered in 2017 include the ruling that separated the legal character of denture production agreement signed together with medical care agreement and found a subcontracting dimension in the former, and the ruling that overcame the limitations of the theory of entire appearance of a fetus as discussed in civil law by using the legal principle of insurance which suggests that unborn child insurance takes effect after the contract is signed and the first installment of the premium is paid in. As more court rulings find the medical specialists responsible for accidents and injuries from drugs, some argue that medication counseling by the druggist who makes and dispenses drugs should be upgraded. And with respect to a court ruling that denied the hospital's responsibility for an infection-involving accident even if there were no records on specific measures taken in infection management, some criticized the court for being too conservative in recognizing responsibilities. And with respect to infectious disease management, some criticized the court for its interpretation and application of the facts in the direction of denying the negligence. In addition, some claimed that it is necessary to establish institutional system for hospital infection control and its aid for victims, and to improve the system including the reversal of the burden of proof given the special nature of hospital infections. A number of rulings on the duty to disclose included the one which stated that the specific matter did not require a doctor's explanation as it was explained or the specific medical service would have been performed even if no explanation had been given. There was a greatly controversial ruling over the scope of indemnification, which accepted the occurrence of multiple scars and deformation as disorders while regarding breast as a thoracic organ. And a Supreme Court ruling over interpreting Medical Service Act was criticized as overstepping the boundary allowed in the law.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.381-391
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• 2008

The eigenvalue technique is introduced to overcome the problem of truncation errors caused by temporal discretization of numerical analysis. The eigenvalue technique is different from simulation in that only the space is discretized. The spatially discretized equation is diagonized and the linear dynamic system is then decoupled. The time integration can be done independently and continuously for any nodal point at any time. The results of eigenvalue technique are compared with the exact solution and FEM numerical solution. The eigenvalue technique is more efficient than the FEM to the computation time and the computer storage in the same conditions. This technique is applied to the solute transport analysis in nonuniform flow fields around underground storage caverns. This method can be very useful for time consuming simulations. So, a sensitivity analysis is carried out by using this method to analyze the safety of caverns from nearly located contaminant sources. According to the simulations, the reaching time from source to the nearest cavern may takes 50 years with longitudinal dispersivity of 50 m and transversal dispersivity of 5 m, respectively.

• Journal of the Korean Chemical Society
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• v.39 no.7
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• pp.501-507
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• 1995

The electronic structure of cis-$[Cr(cyclam)Cl_2]Cl$ has been investigated by the emission and excitation spectroscopy at 77K, and infrared and visible spectroscopy at room temperature. The ten electronic transitions due to spin-allowed and spin-forbidden are assigned. The zero-phonon line in the excitation spectrum splits into two components by $139\;cm^{-1}$, and it can be reproduced by modern ligand field theory. According to the results of ligand field analysis, we can confirm that nitrogen atoms of the cyclam ligand have a strong ${\sigma}$-donor character, but chloride ligand has weak ${\sigma}-$ and ${\pi}-$donor properties toward chromium(III) ion.

• Korean Journal of Materials Research
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• v.3 no.4
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• pp.344-351
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• 1993

The crystal structunes of poly(ethylene terephthalate-eo-1, 4 cyciohexylene dimethylene terephthalate), P(ET CT), copolymers were studied by CPMAS solid state NMR spectroscopy. With the estimation of methylene resonance peaks, the bulkier CT component of the copolymer in the range of 0 20 mol% CT is excluded from the ET crystal lattice, whereas smaller ET component of the copolymer in the range of 66 100 mol% CT can be partially included into the CT crystal lattice. Those different crystallization behavior can be explained with the difference in chain bulkiness and crystal lattice dimension be tween two copolymer compurwnts.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.7
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• pp.178-187
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• 1999

In order to identify a transfer function model with noise, penalty function method has been widely used. In this method, estimation process for possible model parameters from low to higher order proceeds the model identification process. In this study, based on linear estimation method, a new approach unifying the estimation and the identification of ARMAX model is proposed. For the parameter estimation of a transfer function model with noise, linear estimation method by noise separation is suggested instead of nonlinear estimation method. The feasibility of the proposed model identification and estimation method is verified through simulations, namely by applying the method to time series model. In the case of time series model with noise, the proposed method successfully identifies the transfer function model with noise without going through model parameter identification process in advance. A new algorithm effectively achieving model identification and parameter estimation in unified frame has been proposed. This approach is different from the conventional method used for identification of ARMAX model which needs separate parameter estimation and model identification processes. The consistency and the accuracy of the proposed method has been verified through simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1A
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• pp.1-9
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• 2000

This paper presents the error performance of 16 star-QAM with diversity reception in microcell systems in the presence of additive white Gaussian noise(AWGN) and cochannel interference. The differential detection of 16 star-QAM is split into phase detection and amplitude detection. This technique can reduce the degradation of error performance which is due to fading and the complexity of receiver. Diversity reception is proposed to improve the degradation of error performance due to fading. Equal gain and maximal ratio combinings were adopted for the phase detection and the amplitude detection, respectively. The performance of 16 star-QAM was evaluated for various of Rician factor K, maximum Doppler frequency f_DT, signal to cochannel interference ratio and diversity branch L.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.263-263
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• 2017

풍수의 본질은 생기(生氣)와 감응(感應)이다. 즉 사람이 늙어 죽는 것은 가화합체(假化合體)인 형태가 분리되어 화합이전의 진체(眞體)로 돌아가는 것이다. 이 땅으로 돌아간 뼈가 길기(吉氣)에 감응하면 그 자손에게 행복을 미친다. 그것은 마치 동쪽산에 불꽃이 나오면 서쪽산에 구름이 이는 것과 같은 동기상응(同氣相應)과 친자감응(親子感應)이 풍수의 본질이라 할 수 있다 (무라야마 지준/최길성, 1990; 장용득, 1996; 지창룡, 1984; 최창조, 1984; 김성원, 2011a, b, c, d; 2012). 인간의 운명을 결정짓는 것은 여러 가지가 있다. 그 중에서 풍수가 인간의 운명에 끼치는 영향도 지대하다고 할 수 있다. 본 연구에서는 대한민국의 역사상 가장 큰 국정농단 사건의 주역인 최태민-최순실 일가의 음택터에 대한 분석을 위하여 풍수공학적 접근법을 시도하였다. 최태민과 최순실은 대통령의 국정권한을 사사로운 개인의 영달을 위하여 사용하여 국가의 정치 및 경제가 파탄나고 국론분열은 더 심각해지고, 그로인한 국가의 운명이 풍전등화와 같다고 설명될 수 있다. 따라서 최태민과 부친인 최윤성 음택터에 대한 풍수공학적 해석을 통하여 국정농단의 근원을 찾아서 그 원인을 차단할 수 있는 기법을 풍수공학적으로 제시하고자 한다.

• The Journal of Engineering Geology
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• v.32 no.3
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• pp.351-361
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• 2022

Numerical analysis performed to predict the behavior of Ipseok-dae columnar joints in Mudeungsan National Park to understand their stability and movement. The numerical analysis technique, 3DEC, is based on the discrete element method that can analysis discontinuities. The analysis used data for material properties derived from laboratory tests, which found that average density was 2.68 kN/m³, average normal stiffness was 3.15 GPa/m, average shear stiffness was 1.00 GPa/m, average cohesion was 0.51 MPa, and the average friction angle was 33°. The Ipseok-dae columnar joints were modeled on the basis of the field survey data for 15 joints located between the observation platform and the hiking trail. The numerical analysis assessed the behavior of each columnar joint by interpreting the displacement of the edges of its upper and lower surfaces. The greatest maximum displacement was found in columnar joint No. 6, and the greatest minimum displacement was found in joint No. 11. Analyzing the movements of five discontinuities in joint No. 11 indicated that the maximum displacement occurred at the 2nd level. The other levels were ordered 5th, 4th, 1st, and 3rd in terms of subsequent greatest displacements. Considering the total displacement in the 15 studied joints, the Ipseok-dae columnar joints are judged to be stable. However, considering the cultural and historical value of Mudeungsan National Park, it is regarded that the currents slope stability should be maintained by monitoring the individual rock blocks of the joints.