• 소성∙가공
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• 제21권1호
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• pp.49-57
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• 2012

It is difficult to estimate the properties of multilayered sheet because they are composed of one or more different materials. Plastic deformation behavior of the multilayered sheet is quite different as compared to each material individually. The deformation behavior of multilayered sheet should be investigated in order to prevent forming defects and to predict the properties of the formed part. In this study, the mechanical properties and formability of stainless steel-aluminum-magnesium multilayered sheet were investigated. The multilayered sheet needs to be deformed at an elevated temperature because of its poor formability at room temperature. Uniaxial tensile tests were performed at various temperatures and strain rates. Fracture patterns changed mainly at a temperature of $200^{\circ}C$. Uniform and total elongation of multilayered sheet increased to values greater than those of each material when deformed at $250^{\circ}C$. The limiting drawing ratio (LDR) was obtained using a circular cup deep drawing test to measure the formability of the multilayered sheet. A maximum value for the LDR of about 2 was achieved at $250^{\circ}C$, which is the appropriate forming temperature for the Mg alloy. Fracture patterns on a circular cup and thickness of formed part were predicted by a rigid-viscoplastic FEM analysis. Two kinds of modeling techniques were used to simulate deep drawing process of multilayered sheet. A single-layer FE-model, which combines the three different layers into a macroscopic single layer, predicted well the thickness distribution of the drawn cup. In contrast, the location and the time of fracture were estimated better with a multi-layer FE model, which used different material properties for each of the three layers.

• 한국가족관계학회지
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• 제23권2호
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• pp.133-155
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• 2018

Objectives: This study examined the differences in the intention of having a second child and the related factors among Chinese and Vietnamese migrant women from the perspective of adaptation theory. Methods: Data were drawn from the National Survey on Multi-Cultural Families in 2009 and 2015. Among the total 7,615 married migrant women (Korean-Chinese, Chinese-Han, Vietnamese), those within the age group 20-39 within the first 5 years of marriage who had one child were selected. A frequency analysis, chi-squared test, and logit regression analysis were performed. Results: Different ethnic groups had different reasons for having a second child and the related factors also differed between 2009 and 2015. In 2009, after controlling the related variables, the intention of Korean-Chinese and Chinese-Han married immigrant women to have a second child was higher than that of Vietnamese women, but no such difference was found in 2015. Participation in their local community, first marriage, the gender of the first child, and whether they were living with their parents-in-law were associated with the intention of migrant women having a second child in the 2009 analysis model but these factors were not significant in the 2015 analysis model. In the latter model, the household income, a variable related to economic conditions, has a positive effect on the intention of having a second child. Conclusions: The significance of this study supports adaptation theory by addressing the similarity in the childbirth intention between recently married immigrant women and Korean women.

• 한국항공우주학회지
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• 제50권8호
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• pp.541-550
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• 2022

IMM 필터 및 GLRT 기법을 이용하여 무인기용 엔진의 효과적인 실시간 결함 진단 방안을 도출하였다. 이를 위해서 엔진 동적 사이클해석으로부터 선형 진단 모델을 유도하고 잔차 추정을 위한 칼만필터를 도입한 후 각 기법의 특성을 고찰하여 엔진 제어 구동기 및 센서의 결함 진단에 적용하였다. 이 과정에서 IMM 필터로부터 효과적인 FDI 방안을 도출하였고 구동기 결함으로 인한 상태변수의 반응값을 추정하였으며, GLRT로부터는 구동기 및 센서의 결함값 추정과 FDI 기능을 확인하였다. 수치 모의시험 결과를 통해서 FDI를 위한 IMM 필터의 효용성과 각 결함 모드의 결함값 추정을 위한 GLRT 기법의 효용성을 확인하였다.

• 대한조선학회논문집
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• 제59권5호
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• pp.262-270
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• 2022

The emergence of new concept ships, such as autonomous ships, has drawn much attention on the manoeuvrability of ships because of the safe navigation and operation of ships. Although the manoeuvrability of KRISO Container Ship(KCS) has been frequently reported, there have been few documents of representative manoeuvre cases conducted in various methods by one institute. This paper presents the manoeuvrability of the ship in 1/42.0 model scale by 3 methods: free running model tests, horizontal planar motion mechanism tests, and computational fluid dynamics analysis. KRISO reports KCS manoeuvre data: 35° turning circle tests and 20/20(10/10) zigzag manoeuvring tests. In addition, a simple formula for integrating and comparing manoeuvre indices, Manoeuvrability Comparing Simple Index(MCSI), is proposed.

• 디지털융복합연구
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• 제20권3호
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• pp.181-189
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• 2022

모바일 기기의 확산과 ICT 기술로 핀테크 혁신이 더욱 가속화 될 것으로 전망되는 가운데, 최근 금융의 화두는 '디지털 전환'이며, 여기에는 빅데이터의 활용이 주요 요소라 할 수 있다. 특히 오픈 뱅킹이라는 인프라가 마이데이터와 마이페이먼트 산업과 연계되어 금융정보의 이종결합, 자산 조회 및 이체 기능이 결합되는 오픈 파이낸스 시대가 도래고 있다. 마이데이터는 데이터 활용을 통한 가치 창출에 주목하여 나타난 개념으로, 데이터의 주체가 능동적인 자기결정권을 갖는데 의의가 있는데 현재 국내에서도 마이데이터가 시행 되며 전략적 활용방안을 모색되고 있다. 이에 본 연구는 마이데이터 관련 비즈니스 사례를 분석하여 향후 금융의 디지털 전환을 위한 전략적 활용방안을 제시하는 것을 목적으로 하였다. 해외 주요국가에서 마이데이터 개념을 적용한 PSD2 및 오픈뱅킹 정책을 적극 추진하고 있는 가운데 성공적인 비즈니스 모델(Mint, Information Bank, Strands)의 분석을 통해 데이터 기반 비즈니스의 타당성을 확인하고 공통점을 모색하기 위한 사례 연구를 수행하였다. 거래의 효율성과 다양성을 향상시키는 사업 모델을 제공한다는 관점에서 마이데이터는 기존의 사업 모델을 개선할 수 있는 잠재력이 있음을 확인할 수 있었다. 마이데이터는 본인 중심의 모든 데이터로부터 개별적인 데이터 생태계를 쉽게 구현하고 관리할 수 있어야 하는데 개인이 스스로 이를 관리, 통제, 활용하는 것은 현실적으로 어렵다. 따라서 마이데이터 오퍼레이터 또는 마이데이터 서비스 제공자 역할을 할 수 있는 비즈니스 모델이 적극적으로 모색될 필요가 있겠다.

• 디자인융복합연구
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• 제16권4호
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• pp.81-98
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• 2017

이 연구는 프리저브드 플라워 패키지 디자인의 효율적 전개 여부를 평가하기 위해 조형 요소 뿐 아니라 제품 속성을 파악하여 접근하는 방향이 전제되어야 한다는 판단에서 시작되었다. 선행 연구를 기반으로 패키지 디자인의 구성 요건을 재정립하고, 제품 유형 분류 모형을 제안하였다. 패키지 디자인의 구성 원리는 6가지로 사용성, 심미성, 주목성, 독창성, 정체성, 상징성이며, 구성 요소는 크게 4가지 형태, 재질, 색상, 그래픽, 브랜드로 분류하였다. 제품 유형은 제품 정보 측면에서의 위험 지각과 제품 효익 측면에서의 사고 유형을 축으로 하여 4개 영역으로 구분하였다. 제품 유형 모형 영역별 대표 제품을 사례로 들어 패키지 디자인 구성 요소에서 발견되는 특징을 분석하여, 제품 유형에 따라 어떻게 디자인이 적용되어야 효과적이고 효율적인가에 대해 검토하였다. 이 모형에 대입해 프리저브드 플라워 패키지 디자인 전략적 방향성을 도출하였다. 최종적으로 연구용역으로 진행되어 제안된 평택시 프리저브드 플라워 브랜드 '프리저빌'의 패키지를 분석하여 한계점을 찾아보고 프리저브드 플라워라는 제품이 지향해야하는 패키지 디자인 관점을 제언하였다.

• 한국농공학회지
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• 제29권3호
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• pp.125-137
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• 1987

The purpose of this paper is to examine some difficulties in water management of agricultural reservoirs in Korea, for there are approximately more than 15,000 reservoirs which are now being utilized for the purpose of irrigation, along with the much amount of expenses and labors to be invested against droughts and floods periodically occurred. Recently, the effective use of water resources in the agricultural reservoirs with a single purpose, is becomming multiple according to the alterable environment of water use. Therefore, the task to allocate agricultural water rationally and economically must be solved for the multiple use of agricultural reservoirs. On the basis of the above statement, this study aims at suggesting the rational method of water management by introducing an optimal technique to allocate the water in an existing agricultural reservoir rationally, for the sake of maximizing the economic effect. To achieve this objective, a reservoir, called "0-Bongje" as a sample of the case study, is selected for an agricultural water development proiect of medium scale. As a model for the optimum allocation of water in the multi-purpose use of reservoirs a linear programming model is developed and analyzed. As a result, findings of the study are as follows : First, a linear programing model is developed for the optimum allocation of water in the multi-purpose use of agricultural reservoirs. By adopting the model in the case of reservoir called "O-Bongje," the optimum solution for such various objects as irrigation area, the amount of domestic water supply, the size of power generation, and the size of reservoir storage, etc., can be obtained. Second, by comparing the net benefits in each object under the changing condition of inflow into the reservoir, the factors which can most affect the yearly total net benefit can be drawn, and they are in the order of the amount of domestic water supply, irrigation area, and power generation. Third, the sensitivity analysis for the decision variable of irrigation which may have a first priority among the objects indicate that the effective method of water management can be rapidly suggested in accordance with a condition under the decreasing area of irrigation. Fourth, in the case of decision making on the water allocation policy in an existing multi-purpose reservoir, the rapid comparison of numerous alternatives can be possible by adopting the linear programming model. Besides, as the resources can be analyed in connection with various activities, it can be concluded that the linear programing model developed in this study is more quantitative than the traditional methods of analysis. Fifth, all the possible constraint equations, in using a linear programming model for adopting a water allocation problem in the agricultural reservoirs, are presented, and the method of analysis is also suggested in this study. Finally, as the linear programming model in this study is found comprehensive, the model can be adopted in any different kind of conditions of agricultural reservoirs for the purpose of analyzing optimum water allocation, if the economic and technical coefficients are known, and the decision variable is changed in accordance with the changing condition of irrigation area.

• 대한의용생체공학회:의공학회지
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• 제30권2호
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• pp.162-168
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• 2009

Implantable middle ear hearing devices (IMEHDs) have been widely studied as an alternative hearing aids to solve the problems of conventional hearing aids. Vibration transducer of middle ear hearing aids is a key component because vibration characteristics of transducer is directly involved performance of hearing aids. So, the study about middle ear hearing aids concentrate on the transducers. A floating mass type transducer is most efficient. In this paper, we suggest a lumped mechanical model of electromagnetic floating mass transducer implanted on human middle ear. The proposed model enables analysis of the vibration characteristics of a floating mass transducer and prediction of the variation after implant on ossicle that offers a simple and easy to analyze. The parameters was drawn based on the components and the structures of transducer. The Lumped mechanical model was converted by the electrical-mechanical equivalent model, and simulated using PSpice. So, we investigated vibration characteristics of transducer influenced it's components. And we predict vibration characteristics of stapes footplate due to implanted transducer's vibration using combining model of transducer and human ear. To prove the feasibility of the suggested model, we fabricated a differential floating mass transducer (DFMT) as one of floating mass transducers and performed experiments using the human temporal bones.

• 대한교통학회지
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• 제27권2호
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• pp.95-105
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• 2009

도로환경요인과 운전자의 능력의 부조화상태에서 교통사고 위험성이 높아진다는 개념으로부터 도로위험수준을 평가를 하고자 하는 것이 요구-노력모형이다. 본 연구에서는 요구-노력모형의 노력수준을 결정하는 운전자 생체신호의 재분석을 통하여 요구-노력모형의 신뢰성을 높일 수 있는 새로운 신경망 모형구조를 제안하였다. 영동, 호남 및 서해안고속도로에서 149명의 피실험자를 대상으로 검증한 연구결과는 다음과 같이 나타났다. 첫째, 생체신호 파라메타 값에 대하여 Normality Test, Cluster Analysis와 Mann-Whitney 분석에서 기존 요구-노력 모형에서 사용하던 10개의 생체신호 중 5개의 생체신호만이 통계적으로 유의함을 입증하였다. 둘째, 신경망모형은 운전자의 노력수준의 평가에 대한 정확도는 매우 높게 나타났다. 신경망구축을 위해 사용한 집단1의 피실험자별 전체 노력수준의 정확도는 80.0%, 집단 2의 피실험자별 전체 노력수준의 정확도가 74.3%로 나타났다. 셋째, 요구-노력모형에서 노력수준 경계값 결정방법에 따라 호남고속도로 전주IC${\rightarrow}$회덕JCT구간의 단위분석지점에 대하여 도로위험도를 판별한 결과, 2종 오류가 신경망모형 40.5%, 기존 모형 58.8%로 나타났다. 요구-노력모형에 의한 도로위험도 평가가 최종적이기 보다는 전문가 그룹에 의한 상세한 도로안전진단에 앞서 도로위험도를 대략적으로 판별하고자 하는 의도였다고 한다면 보다 많은 검토대상구간을 판별하고, 더 낮은 2종 오류비율을 보인 신경망을 이용한 방법이 요구-노력모형의 취지에 적합하다고 볼 수 있다.

• 한국환경보건학회지
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• 제28권3호
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• pp.1-8
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• 2002

The experiments for the characterization of inactivation were performed in a series of batch processes with the total coliform as a general indicator organism based on chlorine, chlorine dioxide and ozone as disinfectants. The water sam-ples were taken from the outlet of settling basin in a conventional surface water treatment system that is provided with the raw water drawn from the mid-stream of the Han River. The inactivation of total coliform was experimentally ana-lyzed for the dose of disinfectant contact time, pH, Temperature and DOC. The nearly 2.4,3.0,3.9 log inactivation of total coliform killed by injecting 1 mか1 at 5 minutes for chlorine, chlorine dioxide and ozone. For the inactivation of 99.9%(3 log), Disinfectants required were 1.70, 1.00 and 0.60 mか1 for chlorine, chlorine dioxide and ozone, respec-tively. The higher the pH is, the poorer the disinfections effects are in the range of pH 6-9 by using chlorine and ozone. But the irfluence of pH value on killing effects of chlorine dioxide is weak. The parameters estimated by the models of Chick-Watson, Hom, and Selleck from our experimental data obtained for chlorine are: log(N/ $N_{0}$ )=-0.16 CT with n= 1, log(N/ $N_{0}$ )=-0.71 $C^{0.87}$T with n$\neq$1, for Chicks-Watson model, log (N/ $N_{0}$ )= -1.87 $C^{0.47}$ $T^{0.36}$ for Hom model. For chlorine dioxide are: log(N/ $N_{0}$ )= -1.53 CT with n = 1, log(N/ $N_{0}$ )= -2.29 $C^{0.94}$T with n$\neq$1,, for Chicks-Watson model, log(N/ $N_{0}$ )= -3.64 $C^{0.43}$ $T^{0.24}$ for Hom model and for ozone are: log(N/ $N_{0}$ )= -2.59 CT with n = 1, log(N/ $N_{0}$ )= -2.28 $C^{0.36}$T with n$\neq$1, for Chicks-Watson model, log(N/ $N_{0}$ )= -4.53 $C^{0.26}$ $T^{0.19}$ for Hom model.19/ for Hom model.