• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.607-610
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• 2002

최근 5년간 e-Loaming에 대한 중요성과 웹 기반 학습의 활용성은 대부분의 기업에서 LMS(Learning Management System)의 형태로 도입을 하고 있다. 또한, 현재는 학습관리와 컨텐츠의 관리영역을 통합하고 학습 컨텐츠의 객체화를 통한 재사용성과 관리 측면을 극대화하는 노력이 이루어지고 있다. e-Learning을 활용하는 80%이상의 기업이 표준적인 메타데이터와 리파지토리를 기반으로하는 LCMS(Leaning Content Management System)형태로 전환하는 시점에서 LCMS 관린 연구가 요구된다. 본 연구에서는 학습객체를 통한 코스의 개발과 관리 배포를 위한 LCMS를 재사용 가능한 실행 모듈인 컴포넌트 기반으로 구성하고자 한다. 학습 컨텐츠 관리시스템에서의 주요 기능을 계층적으로 체계화하며, LCMS를 위한 컴포넌트 참조 아키텍처를 정의함으로써 개발의 용이성과 시간, 비용의 효율성을 보장한다. 또한, 재사용 및 공유가능한 학습객체를 통한 코스 개발로 학습 컨텐츠의 중복을 피하고 학습과정 개발의 시간 효율성을 기대한다.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2845-2849
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• 2008

Long Term Asset Management(LTAM) means a plan developed by using LCM(Life Cycle Management) process for optimum life cycle management of significant plant assets at each plant across the fleet. As a part of development of LTAM Strategies on nuclear turbines, a method so as to determine the future failure rates for low pressure turbine facilities at a nuclear plant was studied and developed by using both plant specific and industry-wide performance data. INPO's EPIX data were analyzed and some failure rate evaluation values considering preventive maintenance practices were calculated by using EPRI's PM Basis software. As the result, failure rate functions applicable to a priori and a posteriori replacement of low pressure turbines at a nuclear plant were developed and utilized in an assessment of economics of LCM alternatives on the nuclear turbine facilities in the respects of 40-year and 60-year operation bases.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.1234-1237
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• 2013

빅데이터의 중요성이 부각되고 있는 빅데이터의 시대에 교육서비스시장은 스마트 교육이라는 새로운 변화에 따라 많은 변화가 일어나고 있다. 자기 주도적이며 개인화되고 쌍방향커뮤니케이션 등의 특징을 가진 스마트러닝 환경에서는 LMS와 LCMS의 역할이 점점 중요해지고 있다. 현재 콘텐츠의 중요성이 부각되는 정보홍수 시대이므로 LCMS가 해야 할 역할이 크다. 그러나 아직까지는 교육서비스에서 빅데이터의 아키텍쳐와 대용량 데이터 처리 기술을 활용하고 있는 사례는 그다지 많지 않다. 이에 본 논문에서는 빅데이터 기술을 활용한 LCMS에 대해 분석하고 새로운 방안을 제시하고자 한다.

• Communications for Statistical Applications and Methods
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• v.28 no.3
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• pp.233-250
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• 2021

This paper studies if the accuracies of mortality models (LC model vs. 4-parametric model) are aggravated if a mortality structure changes due to the impact of COVID-19. LC model (LCM) uses dimension reduction for fitting to the log mortality matrix so that the performance of the dimension reduction method may not be good when the matrix structure changes. On the other hand, 4-parametric factor model (4-PFM) is designed to use factors for fitting to log mortality data by age groups so that it would be less affected by the change of the mortality structure. In fact, the forecast accuracies of LCM are better than those of 4-PFM when life-tables are used whereas those of 4-PFM are better when the mortality structure changes. Thus this result shows that 4-PFM is more reliable in performance to the structural changes of the mortality. To support the accuracy changes of LCM the functional aspect is explained by computing eigenvalues produced by singular vector decomposition

• Tunnel and Underground Space
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• v.21 no.3
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• pp.151-163
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• 2011

The LCM test is one of the most powerful and reliable methods for designing the disc cutter and for predicting the TBM (Tunnel Boring Machine) performance. It has an advantage to predict the actual load on disc cutter from the laboratory test on the real-size large rock samples, however, it also has a disadvantage to transport and/or prepare the large rock samples and to need an extra cost for experiment. Moreover it is not easy to execute the test for jointed rock mass, and sometimes the design model estimated from the test can not be applied to the real design of disc cutter. In order to break this critical point, lots of numerical studies have been performed. PFC2D can simulate crack propagation and rock fragmentation effectively, because it is useful in particle flow analysis. Consequently, in this study, the PFC2D has been adopted for numerical analysis on cutting power of disc cutter according to the different angle of joint, the different direction of joint, and the different space of joint with jointed rock mass models. From the numerical analyses, it was concluded that the bigger cutting power of disc cutter was needed for reverse cutting direction to joint rather than for forward direction, and the cutting power of disc cutter was increased with decreasing the dip angle of joint and decreasing the space of joints in reverse cutting direction. The more precise numerical model for disc cutter can be developed from comparison between the numerical results and LCM test results, and the resonable guideline is expected for prediction of TBM performance and disc cutter.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.41
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• pp.147-156
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• 1997

This Study deals with the problem of determining a minimum cost sampling inspection plan for destructive testing by attribute. The linear cost model(LCM) is constructed under the assumption that unit cost, destructive testing cost, producer's risk cost, consumer's risk cost are given. For the solution from the LCM, we assumed the uniform distribution as a prior distribution.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.2
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• pp.139-152
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• 2008

A series of numerical experiments were carried out to simulate the rock cutting behavior by TBM disc cutter in a given took condition. AUTODYN-3D, a commercial program capable of simulating three-dimensional dynamic failure, was utilized to carry out the numerical tests over four different disc cutter spacing conditions. After modelling three-dimensional geometries of disc cutter and rock specimen, the linear cutting tests by a disc cutter were simulated for eight different types of rocks. The numerical result, that is the optimum cutter spacing for isotropic rocks had the good agreements with those from linear cutting test. However, for relatively anisotropic or jointed rocks, the specific energy obtained from the numerical tests was almost two-times bigger than the real linear cutting results. Therefore, to simulate cutting procedures for anisotropic rocks realistically, further studies would be necessary.

• Physical Therapy Korea
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• v.25 no.2
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• pp.62-70
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• 2018

Background: The craniocervical flexion (CCF) exercise is one of the effective exercise in correcting forward head posture (FHP). However, some people with FHP achieve CCF with compensatory movements, for example, low cervical flexion using superficial neck flexors such as the sternocleidomastoid (SCM) muscle. No study has yet investigated whether a dual­pres ure biofeedback unit (D-PBU) method to prevent low cervical flexion would be helpful in performing pure CCF movement. Objects: The purpose of this study was to compare the effects of the CCF using D-PBU method and the traditional CCF method on the cross-sectional area (CSA) of the longus colli muscle (LCM) and the activity of SCM muscle in subjects with FHP. Methods: Twenty­four FHP subjects (male: 16, female: 8) were recruited for this study. All subjects performed CCF using two different methods: the traditional CCF method and the CCF using D-PBU method. The CSA of the LCM was measured via ultrasound, and surface electromyography was used to measure SCM muscle activity. Results: The change in CSA of the LCM was significantly larger during the CCF using D-PBU method ($1.28{\pm}.09$) compared with the traditional CCF method ($1.19{\pm}.08$) (p<.05). The SCM muscle activity using the CCF using D-PBU method ($2.01{\pm}1.97$ %MVIC) was significantly lower than when using the traditional CCF method ($2.79{\pm}2.32$ %MVIC) (p<.05). Conclusion: The CCF using D-PBU method can be recommended for increasing LCM activation and decreasing SCM muscle activity during CCF movement in subjects with FHP.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.3
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• pp.345-356
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• 2013

Numerical simulation on rock cutting by a TBM disc cutter was carried out using SPH (Smoothed Particle Hydrodynamics) code. AUTODYN3D, a commercial software program based on finite element method, was used in this study. The three-dimensional geometry of a disc cutter and a rock specimen were modeled by Lagrange and SPH code respectively. The numerical simulation was carried out for Hwangdeung granite for 10 different cutting conditions. The results of the numerical simulation, i.e. the relation between cutter force and failure behavior, had a good agreement with those from LCM test. The cutter forces measured in the numerical simulation had 10% deviation from the LCM test results. Moreover, the optimum cutter spacing was almost identical with the experimental results. These results indicate that SPH code can be successfully used had applicability for simulation on rock cutting by a TBM disc cutter. However, further study on Lagrange-SPH coupled modelling would be necessary to reduce the computation time.

• Tunnel and Underground Space
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• v.23 no.1
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• pp.54-65
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• 2013

The LCM (Linear Cutting Machine) test is one of the most powerful and reliable methods for designing the disc cutter and for predicting the TBM (Tunnel Boring Machine) performance. It has an advantage to predict the actual load on disc cutter from the laboratory test on the real-size large rock samples, however, it also has a disadvantage to transport and/or prepare the large rock samples and to need an extra cost for experiment. In order to overcome this problem, lots of numerical studies have been performed. In this study, the PFC3D (Particle Flow Code in 3 Dimension) has been adopted for numerical analysis on optimum cutter spacing and failure aspects of Busan Tuff. The optimum cutting condition with s/p ratio of 16 and minimum specific energy of $14MJ/m^3$ was derived from numerical analyses. The cutter spacing for Busan Tuff had the good agreements with those of LCM test and numerical analysis by finite element method.