• 문화기술의 융합
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• 제5권4호
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• pp.413-420
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• 2019

본 연구의 목적은 기존의 body fat mass 변수와 고콜레스테롤혈증의 연관성연구를 벗어나, 머신러닝기법을 기반으로 body fat mass 변수들의 조합을 이용하여 고콜레스테롤혈증 예측 모델을 개발하는 것이다. 이러한 연구를 위하여 국민건강영양조사 데이터를 기반으로 두 가지 variable selection 메소드와 머신러닝 알고리즘을 이용하여 총 6개의 모델을 생성하였고 질병 예측력을 비교분석하였다. 여러 body fat mass 관련 변수들 중에서 몸통지방량 변수가 고콜레스테롤혈증 예측력이 가장 우수한 변수인 것을 밝혀내었고, 머신러닝 기반 예측모델들 중에서 correlation-based feature subset selection 기반 naive Bayes 알고리즘을 이용한 모델이 0.739의 the area under the receiver operating characteristic curve 값과 0.36의 Matthews correlation coefficient 값을 얻었다. 이러한 연구의 결과는 향후 국내외 대규모 스크리닝 및 대중보건 연구에서 질병예측분야의 중요정보로 활용될 것으로 예상한다.

• 한국진공학회지
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• 제12권2호
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• pp.105-111
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• 2003

Gas cluster 실험에서 reflectron을 mass selector로서 사용 가능한지를 알아보기 위하여 ‘SIMION’ program을 이용하여 computer simulation하였다. Reflectron 내에서 입자의 비행경로는 질량과는 무관하고 에너지에 따라 변한다. 그러나 $(CO_2)n $ gas cluster의 경우, reflecron을 통과한 직후 cluster의 위치는 cluster의 질량에 따라 공간적으로 분포한다는 것을 알았다. 이것은 cluster의 E/m이 일정하기 때문에 나타난 것으로, 이러한 질량의 공간 분해능이 있기 때문에 reflectron을 mass selector로서 이용할 수 있다는 것을 확인하였다 질량 분해능은 cluster size와 입사각에는 무관하고, 입사위치에 비례한다는 것을 알았다. 이것은 reflectron의 크기를 조정함으로서 질량 분해능을 향상시킬 수 있다는 것을 의미한다. 그러므로 gas cluster 실험에서 reflectron은 질량 분해능이 대단히 우수한 mass selector로서 응용할 수 있다는 것을 확인하였다.

• 한국작물학회지
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• 제50권2호
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• pp.97-104
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• 2005

Mass selection (MS) is an efficient selection method to directly improve highly heritable traits. In the present study, two cycles of MS for ear length were conducted on two sweet corn populations, BC2-l0 and $BC1-10{\times}Syn-II$ after introgression of exotic germplasm. The improved populations generated from these selections were evaluated in comparison with the base populations at two locations, to determine the genetic gains and performance of the improved populations. The two base populations showed varied average realized responses to MS. In BC2-l0 derived population, the realized responses were $9.1\%$ in BC2-l0 C1 and $1.2\%$ in BC2-l0 C2, whereas in$BC1-10{\times}Syn-II$ derived population, the realized responses were$ 5.6\%$ in $BC1-10{\times}Syn-II$ C1 and $2.9\%$ in $BC1-10{\times}Syn-II$ C2. All the improved populations showed longer ears than their respective base populations and the check varieties. Ear length, which was used as the selection criterion in this study, showed high broad-sense heritability in the BC2-l0 and $BC1-10{\times}Syn-II$ derived populations, while fresh ear yield revealed low heritability, indicating that selection for ear length in these populations would be more effective than direct selection for yield. Results of this study indicate that MS conducted on BC2­10 and $BC1-10{\times}Syn-II$ had significantly increased ear length and fresh ear yield in both populations. The improved populations obtained would serve as better germplasm sources and further selection in these populations could offer better responses.

• 설비공학논문집
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• 제10권1호
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• pp.56-65
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• 1998

In this paper, experimental investigation of capillary tube performance for R-407C is performed. The experimental setup is made of real vapor-compression refrigerating system. In this study, mass flow rate is measured for capillary tubes of various diameter and length as inlet pressure and degree of subcooling are changed. These data are compared with the results of a numerical model. The mass flow rates of the numerical model are less than by 14% compared with the measured mass flow rates. It is found that mass flow rate and length for R-407c are less than those of R-22 under the same condition. Also based on this experimental study and the numerical model, a set of capillary tube selection charts for R-407C is constructed.

• 한국시뮬레이션학회논문지
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• 제22권4호
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• pp.139-147
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• 2013

본 논문에서는 질량 분석 방법에 의하여 산출된 단백체 데이터(mass spectrometric proteomic data)의 분류 분석(classification analysis)을 위한 새로운 특성 선택(feature selection) 방법을 제안한다. 이 방법은 i)높은 상관관계를 가지는 중복된 특성을 효과적으로 제거하는 전처리 단계와 ii)토너먼트(tournament) 전략을 사용하여 최적 특성 부분집합(optimal feature subset)을 탐색해 내는 단계로 구성되어 있다. 제안되는 방법을 실제 암진단에 사용되는 공개된 혈액 단백체 데이터에 적용하였으며 널리 사용되는 타 방법과 비교할 때 우수한 성능과 균형된 특이도와 민감도를 달성함을 실증하였다.

• 터널과지하공간
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• 제6권3호
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• pp.197-208
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• 1996

Due to the constraints in pre site-investigation for tunnel, it is essential to redesign the support structures suitable for rock mass conditions such as rock strength, ground water and discontinuity conditions for safe tunnel construction. For the selection of optimum support, it is very important to carry out the rock mass classification and in-situ measurement in tunnelling. In this paper, in a mountain tunnel designed by NATM in hard rock, the selectable system for optimum support has been studied. The tunnel is situated at Chun-an in Kyungbu highspeed railway line with 2 lanes over a length of 4, 020 m and a diameter of 15 m. The tunnel was constructed by drill & blasting method and long bench cut method, designed five types of standard support patterns according to rock mass conditions. In this tunnel, face mapping based on image processing of tunnel face and rock mass classification by RMR carried out for the quantitative evaluation of the characteristics of rock mass and compared with rock mass classes in design. Also, in-situ measurement of convergence and crown settlement conducted about 30 m interval, assessed the stability of tunnel from the analysis of monitoring data. Through the results of rock mass classification and in-situ measurement in several sections, the design of supports were modified for the safe and economic tunnelling.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1994년도 가을 학술발표회 논문집
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• pp.209-216
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• 1994

Rock mass classifications have played an indispensable role in underground construction for several decades. An important issue in rock mass classifications is the selection of the parameters of greatest significance. There appears to be no single parameter that can fully describe a jointed rock mass for underground construction design. In this paper. We find some problems shen applied rock mass classification for underground construction in domestic, analyze the most significant parameters and parameters correlation influencing the behavior of a rock mass, and suggest the Simplied Rock Mass Rating system based on RMR method for effective underground supports.

• 대한기계학회논문집B
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• 제23권2호
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• pp.198-209
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• 1999

This study reports the selection of dependent variables for momentum equations in general curvilinear coordinates. Catesian, covariant and contravariant velocity components were examined for the dependent variable. The focus of present study is confined to staggered grid system Each dependent variable selected for momentum equations are tested for several flow fields. Results show that the selection of Cartesian and covariant velocity components intrinsically can not satisfy mass conservation of control volume unless additional converting processes ore used. Also, Cartesian component can only be used for the flow field in which main-flow direction does not change significantly. Convergence rate for the selection of covariant velocity component decreases quickly as with the increase of non-orthogonality of grid system. But the selection of contravariant velocity component reduces the total mass residual of discretized equations rapidly to the limit of machine accuracy and the solutions are insensitive to the main-flow direction.

• 한국소음진동공학회논문집
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• 제25권4호
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• pp.232-237
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• 2015

Complex dynamic systems are composed of several subsystems. Each subsystems affect the dynamics of other subsystems since they are connected to each other in the whole system. Theoretically, we can derive the exact mass and stiffness matrix of a system if we have the natural frequencies and mode shapes of that system. In real situation, the modal parameters for the higher modes are not available and the number of degree of freedom concerned are not so high. This paper shows a simple method to derive the mass and stiffness matrix of a system considering the connecting points of subsystems. Since the accuracy of reconstructed structure depends on the selection of node and mode, the rule for selection of node and mode are derived from the numerical examples.

• 천문학회보
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• 제46권2호
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• pp.80.2-80.2
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• 2021

Galactic young massive clusters are the ideal laboratories to study massive stellar evolution. Unfortunately, such objects are rare. Of particular interest are so-called Red Supergiant Clusters (RSGCs) that are currently only found toward the Scutum-Crux Galactic arm. Confirming their nature as RSGC is often not straight-fortward as distinguishing RSGs from AGB stars is still difficult even with high spectral resolution spectra. Here we report that broad band colors using 2MASS JHK and GAIA G band data can be useful in reducing the AGB contamination, thus providing selection criteria that effectively reveal the known RSGCs with negligible false positives. On the other hand, we suggest that RSGC4, one of the proposed RSGC candidates, may not be a cluster of RSGs as their colors are not compatible with our selection criteria. We discuss the nature of these stars together with our IGRINS spectroscopic observations. We also employ the same selection criteria to search for RSGC candidates in other parts of the plane, resulting in no prominent candidates.