• Korean Journal of Computational Design and Engineering
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• v.18 no.6
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• pp.385-398
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• 2013

Opening wedge high tibial osteotomy (OWHTO) is widely used to treat unicompartmental osteoarthritis of the knee caused by degenerative deformations of the anatomical axes of the leg. However, since it is difficult to accurately plan the surgical degrees of adjustment such as coronal correction angle and tibial posterior slope angle to align the axes before the actual procedure, a number of studies have proposed analytical models to solve this problem. While previous analytical models for OWHTO were limited to specific cases, this study proposes an analytical osteotomy model (AOM) and a surgical planning system (SPS) that are suitable for a wide range of tibial morphologies and tibia conditions. The validity and generality of the model were verified in a total of 60 OWHTO cases. Results of the test showed that, as predicted, surgical degrees are affected quite significantly by tibia shape and slope of the resected surface. Comparison of the required surgical degrees and the degrees estimated from virtual surgery simulations using AOM showed a very small average difference of $0.118^{\circ}$. SPS, based on AOM, allows the operating surgeon to easily calculate surgical parameters needed to treat a patient.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.3
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• pp.74-84
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• 2005

This paper include the investigation of finding the system characteristics of facility by simulating open-type turbo-pump fed system, which has commercial control valves, using AMESIM (Advanced Modeling Environment Simulation) commercial software. After developing a flight-type control valve on the basis of the results, the system characteristics of facility for control and valve tests is estimated. Especially, one of purposes of this paper is to find PID value of each commercial control valve in the facility for system test. To find suitable control logic, PI and PID modes are also compared. This paper also introduces design parameters of valve and equipment for thrust control and TDS simulation, which are using control valves.

• Journal of the Korean GEO-environmental Society
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• v.15 no.5
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• pp.13-21
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• 2014

This study analyzed the differences in the analysis techniques through a comparative analysis of the various segment's modeling techniques of Shield TBM method and proposed reasonable modeling techniques. Also, this study suggested reasonable estimating methods of load to be applicable in the field through the load analysis and three-dimensional finite element analysis by estimating model of rock mass relaxation load. Estimating method of relaxation area by rock mass rating makes no odds of output in subgrade with high rock mass rating, but so the difference of output is large, that is judged to set conservative design off. In estimating result of rock mass relaxation area by three-dimensional analysis relaxation area of subgrade with low-grade soil was predicted to be positioned at medium-range of many methods, in case of designing segment in subgrade with low-grade soil it needs to actively review estimation of relaxation area through three-dimensional analysis reflecting mechanical tunnel excavation.

• Korean Journal of Construction Engineering and Management
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• v.3 no.2 s.10
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• pp.59-66
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• 2002

EVMS(Earned Value Management System) came to the proper method for integrated cost-schedule control and Government announced EVMS application plan. After that, many studies related adaptability, activation, model, and process reflecting the characteristics of the domestic construction industry are proceeded in construction sites and schools. This thesis is a study of EVMS process. The purpose of this paper is to analyze the problems of previous researches for EVMS Process and to suggest the EVMS application Process based on Project Management Processes of PMBOK. In this kind of view, this thesis suggests the new direction to study EVMS process. And furthermore, this process is suggested for showing a framework of EVMS in Korean construction project are identified.

• Convergence Security Journal
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• v.13 no.1
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• pp.37-43
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• 2013

In 2010, the Ministry of National Defense decided to build a MegaCenter including the cloud computing technology by 2014, as part of the '2012 Information Service Plan', which is now underway. The Cloud computing system environment should be designed applying cloud computing technology and policy for an efficient infrastructure that many IT resources are available in the data center as a concentrated form. That is, the system should be designed in such a way that clouding services will be efficiently provided to meet the needs of users and there will not be unnecessary waste of resources. However, in order to build an optimal system, it should be possible to predict the service performance and the resource availability at the initial phase of system design. In this paper, using the CloudAnalyst simulator to predict availability of the K-defence cloud computing system service, conducts cloud modeling and analysis of the 'Facebook', one of the most famous social network service applications with most users in the world. An Optimal K-Defense cloud computing design model is proposed through simulation results.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.4
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• pp.387-399
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• 2003

The box system that consists only of reinforced concrete walls and slabs we adopted in many high-rise apartment buildings recently constructed in Korea. Recently, many of the box system buildings with pilotis has been constructed to meet the architectural design requirements. This structure has abrupt change in the structural properties between the upper and lower parts divided by transfer girders. For an accurate analysis of a structure with pilotis, it is necessary to have the buildings modeled into a finer mesh. But it would cost tremendous amount of computational time and memory. In this study, an efficient method is proposed for an efficient analysis of buildings those have pilotis with drastically reduced time and memory. In the proposed analysis method, transfer gilders are modeled using super elements developed by the matrix condensation technique and fictitious beams are introduced to enforce the compatibility conditions at the boundary of each element. The analyses of example structures demonstrated that the proposed method used for the analysis of a structure with pilotis will provide analysis results with accuracy for the design of box system buildings.

• Journal of East-West Nursing Research
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• v.14 no.1
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• pp.87-97
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• 2008

Purpose: The purpose of this study was to analyze the factors affecting those commitment to a plan for exercise among Korean with chronic diseases by Pender's health promotion model. Methods: The participants in this study were 315 Korean adults over 18 years of age with chronic diseases who were recruited in hospitals or public health centers in Korea. The instruments used in this study were individual characteristics instrument, Rosenberg's self-esteem scale, Ware's perceived health status, Profile of Mood States and Pender's commitment to a plan for exercises scale. Results: The results of analysis showed that Korean adults with chronic diseases were perceived with relatively low commitment to a plan for exercise while they were perceived with moderate self-esteem, health status, and mood. There were significant differences in the commitment to a plan for exercise according to education level and economic level. The positive relationship between self esteem, perceived health status, and commitment to a plan for exercise were significantly correlated. The experience for exercise was the most influential variable on commitment to a plan for exercise accounting for 40.3% among Korean with chronic diseases. Conclusion: For planning a targeted strategy to increase regular exercise among Korean adults with chronic diseases, nurses have to assess the prior experience of exercise of them. These nursing activities lead to improve their quality of life and encourage to control their symptoms.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.501-506
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• 2001

Computer modeling is essential to evaluate possible design of suspension for a railway vehicles. By creating a simulation, the engineers are able to assess the feasibility of a given design and change the design factors to get a better design. But if one wishes to perform complex analysis on the simulation, such as railway vehicle dynamic, the computational time can become overwhelming. Therefore, many researchers have turned to surrogate modeling. A surrogate model is essentially a regression performed on a data sampling of the simulation. In the most general sense, metamodels(surrogate model) take the form $y(x)=f(x)+{\varepsilon}$, where y(x) is the true simulation output, f(x) is the metamodel output, and $\varepsilon$ is the error between the two. In this paper, a second order polynomial equation is partially used as a metamodel to represent the forty-six dynamic performances for high speed train. The number of factors as design variables of the metamodel is twenty-nine, which are composed the dynamic characteristics of suspension. This metamodel is used to search the optimum values of suspension characteristics which minimize the dynamic responses for high speed train. This optimization is a multi-objective problem which have many design variables. This paper shows that the response surface model which is made through the design of analysis of computer experiments method is very efficient to solve this complex optimization problem.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.3
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• pp.353-359
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• 2010

For achieving economical fuel consumption, an increase in the load bearing capacity, and for environmental conservation, there is a constant demand for lightweight frames of commercial vehicles used in the transportation industry. In this study, a structural analysis of the frame of a heavy flat-bed trailer was performed to determine the optimal design of a new lightweight frame made of high-strength steel. To identify the key design parameters of the trailer frame, Taguchi's orthogonal array was used in the experiments. Using ANSYS, a commercial FEA program, the frame structure was optimized with respect to stress, deflection, and torsional stiffness by performing stress and vibration analyses. A physical model of the trailer was also built to verify the validity of the numerical analyses. Finally, an on-road fatigue test of the new lightweight frame made of the high-strength steel, ATOS80, was performed to confirm the durability of the new design.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.05a
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• pp.134-134
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• 2001

이동통신 망을 통한 멀티미디어 통신의 수요 급증으로, 차세대 이동통신 시스템에서는 패킷 교환에 기초한 망 구조가 사용될 것으로 예측된다. VOD(Voice Activity Detector)를 갖는 음성 단말은 데이터를 발생시키는 talk spurt(평균이 t$_1$인 지수분포를 따름)와 데이터를 발생시키지 않는 silence period(평균이 t$_2$인 지수분포를 따름)의 두가지 상태를 갖는 마코프 체인으로 모델링된다. Goodman at. al.은 음성 단말들이 talk spurt동안만 데이터를 전송하게 함으로써 더 많은 가입자들을 수용할 수 있는 PRMA(Packet Reservation Multiple Access) 기법을 제안되었다. PRMA 방식에서는 시간 축이 슬롯들로 구성되며 여러개의 슬롯들로 프레임이 형성된다. Silence period 상태에 있던 음성 단말은 talk spurt 상태가 되면 talk spurt의 첫 번째 데이터를 하나의 슬롯을 통해 전송하게 된다. 이때 단말들은 각 슬롯에서 데이터를 전송할 수 있는 확률을 나타내는 채널 접근 확률(channel access probability)에 의해 데이터를 전송하게 되며 전송에 성공하면 슬롯을 예약함으로서 다음 프레임부터는 동일한 위치의 슬롯을 통해 데이터들을 전송하게 된다. DS/CDMA(Direct Sequence/code Division Multiple Access)는 이동통신 단말의 수용 용량상의 이점, 소프트 핸드오버 능력, 보다 용이하게 셀 계획을 세울 수 있는 점 등에 의해 차세대 이동통신 망에서 채택될 예정이다. CDMA 시스템은 간섭(interference)에 의해 용량이 제한을 받게 되며, MAI(Multiple Access Interference)가 시스템의 성능에 많은 영향을 미치게 된다. Brand, et. al.은 간섭의 분산을 줄이기 위해 PRMA 개념을 DS/CDMA 환경으로 확장한 Joint CDMA/PRMA 프로토콜을 제안하였다. 이때 각 슬롯에서의 데이터 전송확률을 그 슬롯에서 예약상태에 있는 음성 단말의 수에 의존하게 하는 방식을 사용하였으며 데이터 전송확률을 나타내는 채널 접근 확률들을 시뮬레이션을 통해 유도하였다. 한편 음성 단말에게는 실시간 서비스를 제공해 주어야 하는 대신 데이터 단말에게는 실시간 서비스를 제공해 주지 않아도 되므로, 트래픽이 많을 때에는 음성 단말의 데이터 전송에 우선권을 주는 것이 바람직하다. 이를 위해서 Brand, et. al.은 채널 접근 확률을 각 슬롯의 트래픽 상태에 따라 적응적으로 산출하는 기법을 제안하였다. 본 연구에서는 Joint CDMA/PRMA의 성능이 채널 접근 함수의 효율성에 많이 의존하게 되므로 보다 효율적인 채널 접근 확률을 구하는 방법을 제안한다. 즉 채널 액세스 확률을 각 슬롯에서 예약상태에 있는 음성 단말의 수뿐만 아니라 각 슬롯에서 예약을 하려고 하는 단말의 수에 기초하여 산출하는 방법을 제안하고 이의 성능을 분석하였다. 시뮬레이션에 의해 새로 제안된 채널 허용 확률을 산출하는 방식의 성능을 비교한 결과 기존에 제안된 방법들보다 상당한 성능의 향상을 볼 수 있었다.