• 한국운동역학회지
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• 제27권3호
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• pp.189-195
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• 2017

Objective: The aim of this study was to examine the effect of foot landing type (forefoot vs. rearfoot landing) on kinematics, kinetics, and energy absorption of hip, knee, and ankle joints. Method: Twenty-five healthy men performed single-leg landings with two different foot landing types: forefoot and rearfoot landing. A motion-capture system equipped with eight infrared cameras and a synchronized force plate embedded in the floor was used. Three-dimensional kinematic and kinetic parameters were compared using paired two-tailed Student's t-tests at a significance level of .05. Results: On initial contact, a greater knee flexion angle was shown during rearfoot landing (p < .001), but the lower knee flexion angle was found at peak vertical ground reaction force (GRF) (p < .001). On initial contact, ankles showed plantarflexion, inversion, and external rotation during forefoot landing, while dorsiflexion, eversion, and internal rotation were shown during rearfoot landing (p < .001, all). At peak vertical GRF, the knee extension moment and ankle plantarflexion moment were lower in rearfoot landing than in forefoot landing (p = .003 and p < .001, respectively). From initial contact to peak vertical GRF, the negative work of the hip, knee, and ankle joint was significantly reduced during rearfoot landing (p < .001, all). The contribution to the total work of the ankle joint was the greatest during forefoot landing, whereas the contribution to the total work of the hip joint was the greatest during rearfoot landing. Conclusion: These results suggest that the energy absorption strategy was changed during rearfoot landing compared with forefoot landing according to lower-extremity joint kinematics and kinetics.

• Nuclear Engineering and Technology
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• 제3권1호
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• pp.21-31
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• 1971

금속의 소성변형에 필요한 일의 일부는 전표면자유에너지 (Total Surface Free Energy)의 변화에 소모된다. 전표면자유에너지 변화는 비표면 자유에너지 (Specific Surface Free Energy)에 의해 변화하며 비표면자유에너지는 분위기에 따라 달라 진다. 열역학적규명, 체적불변율과 흡착으로 인한 두 개의 판이하게 다른 강화 혹은 약화를 초래하는 전위(Dislocation) 상호작용기구를 기반으로 금속의 소성변형으로 인한 가공경화, 응력 및 에너지에 미치는 분위기의 영향을 이론식으로 도출했다. 이론식은 진공중금속표면장력 (${\gamma}$$_{s}$), 개면장력 (${\gamma}$$_{se}$ ), 포면전위밀도($\rho$$_{s}$), 내부전위 밀도($\rho$$_{i}$)와 표면노출율(f)의 함수로 표시할 수 있었다. 이론식을 이용하여 각기 다른 분위기내에서의 금속의 기계특성을 예측 비교해봤다.다.다.

• Journal of Electrical Engineering and Technology
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• 제7권6호
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• pp.1023-1033
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• 2012

An underwater planar covering problem is studied where the coverage region consists of polygonal cells, and line sweep motion is used for coverage. In many subsea applications, sidescan sonar has become a common tool, and the sidescan sonar data is meaningful only when the sonar is moving in a straight line. This work studies the optimal line sweep coverage where the sweep paths of the cells consist of straight lines and no turn is allowed inside the cell. An optimal line sweep coverage solution is presented when the line sweep path is parallel to an edge of the cell boundary. The total time to complete the coverage task is minimized. A unique contribution of this work is that the optimal sequence of cell visits is computed in addition to the optimal line sweep paths and the optimal cell decomposition.

• 치위생과학회지
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• 제4권2호
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• pp.55-60
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• 2004

본 연구는 치위생과 학생들의 새로운 직업가치관 유형을 구명하는데 있으며, 3개 대학 치위생과 신입생 280명을 대상으로 자료를 수집하였으며, 이 중 242매를 분석하였다. 2차에 걸친 요인분석에 의해 직업가치관을 유형화 하였으며, 이 연구를 통해 얻어진 결과는 다음과 같다. 1. 치위생과 신입생들의 직업가치관 유형은 (1) 지위 (2) 경제적 보상 (3) 사회 기여 (4) 성취 (5) 능력 (6) 직업흥미 등 6개 유형으로 분류할 수 있다. 2. 사회기여, 성취, 능력, 직업흥미 유형은 내재적 가치관으로, 지위와 경제적 보상 유형은 외재적 직업가치관으로 분류할 수 있다. 3. 치위생과 신입생들의 외재적 가치관(4.24점)은 내재적 가치관(3.86점)보다 다소 높게 나타났다. 4. 치위생과 신입생들이 중요하게 생각하는 직업가치관 유형은 경제적 보상(4.39점), 지위(4.09점), 성취(4.07점), 능력(3.98점), 직업흥미(3.91점), 사회기여(3.46점) 순으로 나타났다.

• Journal of applied mathematics & informatics
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• 제41권1호
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• pp.215-228
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• 2023

The ready-made garments (RMG) have been making a crucial contribution about of 81% of total export and 12.36 % of total GDP of the country which is now the single biggest export earner for Bangladesh. The cheap production cost is the key important factor to explore this RMG sector. But these RMG sector is running on the basis of intuition based decisions. Though they are making profit it is not optimal. In this study, a deterministic model is developed to help the RMG to minimize the production cost and to maximize their profit along with optimal utilization of available resources. 10 different types of products are taken from one of the garments factories of Gazipur, Dhaka to prepare this research work. This model suggests the manufacturer on which products along with how much should be produced to meet the future demand by maintaining the lowest production cost that ultimately maximize the profit of the organization, and also helps Bangladesh to compete in the international market with 'Made in Bangladesh'. LINDO programming is used here to solve this LP model.

• 한국철도학회논문집
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• 제12권2호
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• pp.260-266
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• 2009

위험도분석은 철도사고해석에 주로 사용되는 이론이다. 위험도 분석의 목적은 전설공사전체 과정에서 주요사고부 사고요인과 잠재적인 원인 및 기여정도 등을 조사 분석하는 것이다. 본 논문은 건설공사 현장에서 발생하는 사고원인과 패턴을 분석하고 사고빈도와 심각도를 고려한 위험도 지수를 계산하여 상대적인 위험도 평가를 제공하고자 하는 것이다. 이를 기반으로 사고 위험도 지수의 일관성을 유도하고 위험도 평가를 위한 정량적인 기준을 제공하고자 하였다.

• 한국대기환경학회지
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• 제6권2호
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• pp.155-160
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• 1990

During the period from Mar. 1985 to Feb. 1988, airborne particulate matters were collected and size fractionated by the ANdersen high volume air sampler in Seoul. The concentrations of several heavy metals (Pb, Cu, Zn, Fe, Mn) and benzo(a)pyrene were determined to investigate the size distributions and seasonal variations. And with respect to seven components in the total suspended particulate (TSP), the factor analysis was performed for three groups such as the coarse particles (> 2 $\mu$m), fine particles (< $\mu$m) and TSP. As a result of factor analysis by using the varimax method, the chemical components in the TSP were able to characterize with two principal factors. The first factor, F1 was considered to be a factor indicating the contribution of natural sources and the second factor, F2 was a factor indicating the degree of artificial sources. Each components in the TSP was divided into two main groups of components originated from soil and/or road dust and pollutants originated from automobiles and/or human work.

• International Journal of Aeronautical and Space Sciences
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• 제14권2호
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• pp.193-199
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• 2013

This work investigates the orbital perturbations of the cubesats that lie on LEO due to Earth albedo. The motivation for this paper originated in the investigation of the orbital perturbations for closed- Earth pico-satellites due to the sunlight reflected by the Earth (the albedo). Having assumed that the Sun lies on the equator, the albedo irradiance is calculated using a numerical model in which irradiance depends on the geographical latitude, longitude and altitude of the satellite. However, in the present work the longitude dependency is disregarded. Albedo force and acceleration components are formulated using a detailed model in a geocentric equatorial system in which the Earth is an oblate spheroid. Lagrange planetary equations in its Gaussian form are used to analyze the orbital changes when $e{\neq}0$ and $i{\neq}0$. Based on the Earth's reflectivity data measured by NASA Total Ozone Mapping Spectrometer (TOMS project), the orbital perturbations are calculated for some cubesats. The outcome of the numerical test shows that the albedo force has a significant contribution on the orbital perturbations of the pico-satellite which can affect the satellite life time.

• 디지털융복합연구
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• 제18권9호
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• pp.199-210
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• 2020

본 연구는 간호사 세대별 직업가치관과 직무열의의 차이를 확인하고, 직업가치관이 직무열의에 미치는 영향을 확인하기 위해 실시되었다. 간호사 256명이 연구에 참여하였고, 간호사 세대별 직업에 대한 가치관과 직무열의의 차이를 확인하기 위하여 일원배치분산분석(ANOVA)을, 직업가치관이 직무열의에 미치는 영향을 확인하기 위해 다중회귀분석을 실시하였다. 간호사들은 직업생활에서 경제적 보상, 고용안정성과 쾌적한 근무환경을 중요하게 생각하고, 자율성을 포함하는 자유 재량권, 승진기회 그리고 사회적 기여를 상대적으로 덜 중요하게 생각하였다. 세대별 차이에서 Y-세대와 Z-세대는 X-세대에 비해 일의 흥미와 시간적 여유에 높은 가치를 두었고, 직무열의에 영향을 미치는 직업가치관의 세부요인은 사회적 기여가, 직업가치관 외 요인으로는 전반적인 건강상태, 업무에 대한 육체적 부담감, 우울로 파악되었다. 세대별 직업가치관이 직무열의에 미치는 영향요인으로 X-세대는 사회적 기여가, Y-세대는 사회적 인정이, Z-세대는 시간적 여유와 자아실현으로 나타났다. 본 연구는 세대별 직무열의에 미치는 영향요인을 파악하여, 다양한 세대가 함께 일하는 간호조직에서 효과적인 인적자원관리를 위한 정책개발에 필요한 기초자료를 제공함에 그 의의가 있다.

• Safety and Health at Work
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• 제5권3호
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• pp.147-151
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• 2014

Background: Agriculture ranks among the most dangerous trades worldwide. There is, however, still a lack of knowledge on nonfatal injuries in agriculture. The aim of this study was to describe the nature and occurrence of nonfatal injuries in farmers in two counties in central Norway. Methods: A questionnaire was sent to 7,004 farmers in Norway. We asked for information about the respondents and the farm, whether the farmer had had work-related injuries on the farm during the past 12 months, and details about the incidence and seriousness of the injury. Results: A total of 2,699 respondents gave a response rate of 42%. Of the respondents, 249 (9.2%) reported one or more work-related injuries. The most usual cause of injury involved an animal, and >75% of these happened inside the outbuilding. Among these, 17.5% had a consequence of sick leave or a more serious result. When all the accidents were analyzed by stepwise logistic regression, only the variables: works alone, has >3,500 stipulated working hours at the farm, and the type of production were statistical significant explanatory variables for having an injury. Conclusion: Incorporating safety aspects to a greater extend in the design and construction of outbuildings would make a substantial contribution to injury prevention in agriculture.