• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.1
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• pp.18-31
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• 2018

Rotorcrafts have more severe crashworthiness conditions than fixed wing aircraft owing to VTOL and hovering. Recently, with the increasing demand for highly efficient transportation system, application of composite materials to aircraft structures is increasing. However, due to the characteristics of composite materials that are susceptible to impact and crash, demand to prove the crashworthiness of composite structures is also increasing. The purpose of present study is to derive the structural concept of composite subfloor for rotorcrafts and verify it. In order to design a crashworthy composite subfloor, the conceptual design of the testbed helicopter for the demonstration and the derivation of energy absorbing requirement were carried out, and the composite energy absorber was designed and verified. Finally, the testbed for the demonstration of a crashworthy composite structure was fabricated, and performed free drop test. It was confirmed that the test results meet the criteria for ensuring occupant survivability.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.4
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• pp.26-35
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• 2003

For the recognizing system to be classified the same or different images in the nature the rotation, scale and transition invariant features is to be necessary. There are many investigations to get the feature for the recognition system and the log-polar transform which is to be get the invariant feature for the scale and rotation is used. In this paper, we suggested the character recognition methods which are used the centroid method and the log-polar transform with the interpolation to get invariant features for the character recognition system and obtained the results of the above 50% differential ratio for the character features. And we obtained the about 90% recognition ratio from the suggested character recognition system using the BPEJTC which is used the invariant feature from the Mellin transform method for the reference image. and can be recognized the scaled and rotated input character. Therefore, we suggested the image character recognition system using the Mellin transform method and the BPEJTC is possible to recognize with the invariant feature for rotation scale and transition.

• Journal of Korean Society of Transportation
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• v.27 no.6
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• pp.97-106
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• 2009

The purpose of this study is to analyze factors for resolving problems of Jejusi Residential Parking Permit Program and to draw up a plan by examining Jejusi case. This program was started by way of showing an example in October, 2005, and then has been put in practice in the heart of Jejusi since October, 2007. Jejusi government introduced this system to prevent all kinds of accidents by the indiscreet parking near the residental street and to guarantee the rights to live comfortably by encouraging a pleasant parking environment. As the result of the survey which is about residents' participation from the process of decision-making, the answers such as "Should Participate" and "Surely should participate" are at the high rate of 87.5 percent. A matter of the utmost importance is that this system should be reformed to make the visitors pay parking if they want to park near there. Almost 36 percent of the respondents have a negative opinion, and this is because they consider their visitors. Especially the important factors from the Logistic Regression Analysis are that the government should exercise stricter control over illegal parking, that the system should be improved for the visitors to pay parking, and that the government should support the declining sales of the shops near shopping streets. The suggestions are as follows. First, the government should enforce on reducing the illegal parking. Second, they should secure the parking lots for visitors. Third, they should minimize the impact on the declining sales of the shops near shopping streets.

• KDI Journal of Economic Policy
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• v.10 no.4
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• pp.61-81
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• 1988

우리나라 택시산업(産業)에 대한 정부규제(政府規制)는 크게 보아 요금규제(料金規制), 면허규제(免許規制) 그리고 서비스관련규제(關聯規制)로 나눌 수 있다. 정부규제에 의한 문제점으로서는 요금규제(料金規制)에 의한 초과수요(超過需要)의 존재와 제한적인 면허발급제도(免許發給制度)에 의해 발생한 면허에 대한 프리미엄과 이의 배분을 둘러싼 여러가지 비효율(非效率)과 형평(衡平)의 문제(問題)라고 할 수 있다. 우리나라 택시산업(産業)은 비호출방식(非呼出方式)의 노상유객(路上誘客)을 주로 하는 소위 순항식(巡航式)(cruising)시장(市場)이기 때문에 자유경쟁(自由競爭)의 상태에서는 시장정보전달(市場情報傳達)의 불완전성(不完全性)으로 인한 시장실패(市場失敗)의 가능성(可能性)이 존재한다고 할 수 있다. 따라서 이것을 보정(補正)하기 위한 가격규제(價格規制)의 필요성(必要性)은 인정할 수 있으나, 정부에 의한 제한적인 사업면허(事業免許)의 발급(發給)과, 임의적인 증차결정(增車決定) 및 배분방식(配分方式)은 그 정당성(正當性)이 의문시된다고 할 수 있다. 따라서 장기적(長期的)으로 택시에 대한 면허제(免許制)는 폐지되어야 할 것이다. 그러나 택시증차(增車)의 문제는 도시교통혼잡의 문제와 관련이 있으므로, 중(中) 단기적(短期的)으로는 현행의 직접규제방식(直接規制方式)을 개선하여 일정한 자격을 갖춘 출원자(出願者)에게는 일정금액의 공탁금(供託金)만 납부하면 의무적으로 면허를 내어주는 간접규제방식(間接規制方式)으로의 전환을 고려해야 할 것이다. 또한, 태당(台當) 1일(日) 승객회전률(乘客回轉率)의 증가를 통한 승차난완화(乘車難緩和)를 위해 현행(現行) 요금체계(料金體系)를 개선해야 할 것이다.

• Journal of dental hygiene science
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• v.9 no.3
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• pp.319-326
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• 2009

The purpose of this study was to examine the Influence of the experience of Childcare Teacher about oral health education on oral health behaviors. For this, Questionnairs to be self-filled up about experience of oral health education were carried out to 267 childcare teachers who are working in nurseries in Geongnam province. The date was analysed using the SPSS 12.0 program. The obtained result were as follows. Among the respondents who are not under stress of oral health. 8.1% respondents had the oral health education and 7.7% others didn't have it. For toothbrushing methods, it was found that 25.3% used manual toothbrushing with experience in dental education(up and down toothbrushing monement) and 35.4% used semi automatic toothbrushing(rotational movement). 37.1% respondents had experiences in oral health education, 69.7% respondents were instructed in the oral health at public health center, and 61.6% respondents were instructed in the oral health a theory(toothbrushing guidance). Among the respondents who answered that oral health education should be necessary, 83.4% of those have already had oral health education where as 73.8% respondents have not had the education. 67.7% of the respondents who want to participate in the oral health education is corresponding to those with experience in dental education, 66.1% respondents with no education feel the necessity of the oral health education.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.4 no.1
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• pp.53-61
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• 2010

In this paper, We investigated the characteristic analysis of flexibility and muscle strength for exercise to verify capacity in rehabilitation exercise of lumbar using lumbar strengthen exercise instrument. We have experiment in 20th years man and woman who are 20 subject with no medical history, we divided subjects into control group with no exercise and training group with lumbar strengthen exercise. We used Hi-Spine(Medicalscience.korea) also, provided exercise 40 minute a day, three days a week and progressed total four weeks. Moreover in our experiment, subjects exercised four postural position as lay down, sit, stand and stretch each ten minute. We measured trunk extension backward, trunk flexion forward, evaluation of based physical fitness and lumbar joint torque. The reults have shown that there more improved all for flexibility, based physical fitness and lumbar joint torque in training group than control group. We indicated that by rotating 3-D axis movement flatform of exercise instrument, muscle spindle in subject have been stimulated and these rotation direction and angle caused muscle tonus and contraction that makes muscle, flexibility and based physical fitness improve more. Our study can be used rehabilitation exercise program to aged people and patient with lumbar injury.

• The Korean Journal of Applied Statistics
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• v.31 no.3
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• pp.353-366
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• 2018

This study uses mixed-effects models to predict thigh soft tissue artefact (STA), relative movement of soft tissue such as skin to femur occurring during hip joint motions. The random effects in the model were defined as STA and the fixed effects in the model were considered as skeletal motion. Five male subjects without musculoskeletal disease were selected to perform various hip joint rotational motions. Linear mixed-effects models were applied to markers' position vectors acquired from non-invasive method, photogrammetry. Predicted random effects showed similar patterns of STA among subjects. Large magnitudes of STA appeared on the points near the hip joint regardless of sides; however, small values appeared on the distal anterior.

• Journal of Korean Society of Transportation
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• v.20 no.7
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• pp.87-94
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• 2002

2001년 경찰청 $\ulcorner$2001년판 교통사고통계$\lrcorner$ 자료에 의하면 사고피해의 정도를 나타내는 치사율에 있어서 중앙선침범사고가 과속사고와 함께 가장 높은 수치를 보이고 있으며, 대형 교통사고의 39.5%가 중앙선 침범에 의해 발생한 것으로 나타났다. 실제로 2000년 한 해 동안 총 사고건수 290,481건 중 중앙선 침범에 의해 18,931건 (6.52%)의 교통사고가 발생하여 사망자 1,472명, 부상자 35,046명으로 전체 교통사고 사망자의 14.38%, 부상자의 8.21%를 점하고 있는 것으로 나타났다. 이와 같이 전체 교통사고에서 중앙선침범사고가 차지하는 비중 이 높아지고 있어 중앙선침범사고를 줄이기 위한 대책의 일환으로 중앙분리대, 표지병, 시선 유도봉 등과 같은 중앙선침범 예방시설물을 설치하고 있으나, 해당 시설물에 대한 설치기준이 없는 실정이다. 이렇듯 중앙분리대 설치기준의 부재로 인해 중앙선침범사고 발생과 이에 따르는 경제적인 교통사고 비용손실, 그리고 중앙분리대의 과다설치로 인한 국가 재원의 낭비는 간과할 수 없는 문제점을 내포하고 있다. 이러한 점에 착안하여 기존에 지방부 2차로 도로의 직선부에 대한 중앙선침범사고 예측모델이 개발되었고 본 연구에서는 그 연장선상에서 지방부 2차로 도로의 곡선부에 대한 중앙선침범사고 예측모델에 대한 중앙선침범사고 예측모델의 개발을 통해 중앙선침범사고에 대한 사회적 비용을 산정하고, 현재 설치하여 운영중인 중앙선침범 예방시설물의 설치비용간의 비용-편익분석을 통해 얻어진 기준으로 중앙선침범 예방시설물 설치의 가부에 대한 보다 현실적이고 비용-효율적인 중앙선침범 예방시설물 설치기준을 제시함으로써 교통사고 비용손실을 최소화하고, 중앙분리대의 효율적 설치방안의 도입을 통한 경제적 이익창출을 도모하고자 한다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.6
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• pp.523-531
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• 2008

In hole type CPTu equipment which combines the concepts of inhole test method and piezocone test method was newly developed in order to evaluate the dynamic properties of marine soils. It is possible to perform inhole type CPTu without any additional source device because the source and receiver are contained inside the cone rod, which is different from the conventional seismic cone system. In this study, laboratory tests using kaolinite as soft soil and numerical simulations using finite element method were carried out to investigate the effects of several parameters including test methods and soil conditions on the test results from inhole type CPTu and to find out the optimum test method. It was found that it is necessary to maintain the length of swing arm as well as the distance between source and receiver consistently to obtain the rigorous test results. The laboratory test and numerical results also reveal that contrary to the input wave frequency, the water content of soil layer and the disturbance due to the installation of swing arm apparently affect the shear wave velocity.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.704-711
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• 2023

This paper discusses the control method of BLDC(Brushless Direct Current) motor that has similar electrical characteristics with DC motor but has improved its lifespan and reliability. The BLDC motor can improve durability and speed stability by using rotor position information to eliminate commutators that require mechanical contact with DC motors. In this study, a controller for a DC motor was designed based on the fact that the current in the windings of a BLDC motor is a square-wave current like the current flowing in the armature of a DC motor. Next, the designed controller was applied to a 3-phase BLDC motor to confirm the effectiveness of the controller. In detail, a single-phase DC motor with electrical parameter values of a three-phase BLDC motor was modeled and a PI controller for motor speed control was designed by applying the root locus method to the derived system. The speed control simulation of the DC motor was performed to confirm the validity of the controller, and the same controller was applied to the speed control of the 3-phase BLDC motor implemented in MATLAB. From the simulation, similar results of the DC motor were obtained in the 3 phase BLDC motor and confirmed the usefulness of the proposed control scheme.