• 대한기계학회논문집B
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• 제20권1호
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• pp.369-376
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• 1996

Variations of the drag and lift forces of a circular cylinder in a planar turbulent jet were experimentally investigated. The force was directly measured using the load cell and estimated by integrating the pressure distribution on the cylinder. As the cylinder moves outward from the center of the jet, the direction of lift force changes and the drag force decreases. Reynolds number, the ratio of cylinder's diameter to half width of jet had effect on maximum drag coefficient and the location where the direction of lift changes.

• 한국기계가공학회지
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• 제20권6호
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• pp.51-58
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• 2021

The notion of leisure has changed with industrial development and improvement in life quality. Bicycling is a healthy sport; it is an exercise performed while enjoying nature. There have been many changes in the materials that are used to manufacture the bicycle frame. Iron and aluminum have been mainly used in bicycle frames. However, carbon-based materials are lighter and stronger than metal frames. The bicycles made of carbon composite changes frame rigidity depending on the direction of the carbon sheet sacking angle. We study the direction of composite material and how they affect the stiffness of frames based on the stacking angle.

• Journal of Positioning, Navigation, and Timing
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• 제10권1호
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• pp.29-34
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• 2021

Recently, many studies have considered the effect of atmospheric pressure loading (APL) on precise global navigation satellite system (GNSS) data processing. The APL deforms the Earth's crust. It can often exceed 10 mm in radial displacement. In this study, we analyze the APL effect on Multi-GNSS kinematic precise point positioning (PPP). In addition, observations received at two GNSS reference stations (DAEJ and SUWN) in South Korea were processed. The absolute position changes for the two stations were compared to before and after applying the APL effects from January 1 to February 29, 2020. The crust of South Korea was most affected by the APL in the up direction. With the APL model, the difference in daily position changes was mostly within 4 mm in the radial direction. On the other hand, the horizontal components (east-west and north-south) were relatively less affected than the radial component.

• 한국ITS학회 논문지
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• 제21권4호
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• pp.96-114
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• 2022

본 연구는 우리나라 도시물류를 대상으로 과거 추세를 분석하고 미래 변화를 전망하여 도시발전에 선제적으로 대응할 수 있는 정책 방향을 제시하였다. 연구 범위는 물류정책기본법에서 제시하는 국가물류기본계획과 지역물류기본계획의 변화를 중심으로 하였다. 연구 진행은 국가물류기본계획을 근간으로 과거부터 현재까지 도시물류와 관련된 정책 변화를 살펴봄과 더불어 장래 예상되는 물류환경 변화에 대응하는 국가의 정책기조를 파악하였다. 그리고 이를 서울시 도시물류기본계획의 내용과 접목시켜 앞으로 도시물류기본계획에서 계속 추진하거나 새롭게 추가해야 할 물류정책을 제안하였다. 정책 제안은 장래 물류환경을 정책적, 사회적, 기술적 변화로 구분하여 제시하였다. 분야별로는 도시계획(10개 정책), 교통계획·ITS(8개 정책), 물류기술·ITS(6개 정책) 및 법·제도(8개 정책) 등이다. 정책의 지속성으로 구분하면 현재 추진 중인 정책이 계속되어야 할 것은 15개, 앞으로 새롭게 도입해야 할 정책은 17개이다.

• Geomechanics and Engineering
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• 제17권3호
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• pp.237-245
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• 2019

In deep mixed rock strata, a double shield TBM (DS-TBM) is easy to be entrapped by a large force during tunneling. In order to reduce the probability of the entrapment, we need to investigate a favorable driving direction, either driving with or against dip, which mainly associates with the angle between the tunneling axis and strike, ${\theta}$, as well as the dip angle of rock strata, ${\alpha}$. We, therefore, establish a 3DEC model to show the changes of displacements and contact forces in mixed rock strata through LDP (longitudinal displacement profile) and LFP (longitudinal contact force profile) curves at four characteristic points on the surrounding rock. This is followed by a series of numerical models to investigate the favorable driving direction. The computational results indicate driving with dip is the favorable tunneling direction to reduce the probability of DS-TBM entrapment, irrespective of ${\theta}$ and ${\alpha}$, which is not in full agreement with the guidelines proposed in RMR. From the favorable driving direction (i.e., driving with dip), the smallest contact force is found when ${\theta}$ is equal to $90^{\circ}$. The present study is therefore beneficial for route selection and construction design in TBM tunneling.

• 복식문화연구
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• 제17권3호
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• pp.472-483
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• 2009

The purpose of this study is to analyse the effects of knit samples' mechanical properties on changes of skirt length of knit flared skirt, and to compare it to the knitting method of a seamless knitted flare skirt. So, I compared the appearance and 3-dimensional shape of a seamless knitted flare skirt with those of a fully cut knit flared skirt. For this study, 18 kinds of cut and sew or seamless knitted test garment were made. The data analysis methods used in this study were descriptive statistics, one-way ANOVA, correlation analysis, and regression analysis. The results are as follows: The result of the evaluation of knit samples' mechanical properties by the KES-FB system showed that elongation decreased as gauge increased and course direction was greatest among grain directions. The length change after wearing the knitted flare skirts appeared wholly equal to the seamless knitted, compared with the cut and sew. The change was biggest at $180^{\circ}$, 7G of the cut and sew. In grain direction, bias cut showed more than 1.2cm of length change. As the weight and thickness increased, the length changes become larger. The regression analysis indicated that the greatest contributive variables on the length changes were elongation, weight, and thickness.

• 열처리공학회지
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• 제12권1호
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• pp.21-30
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• 1999

The present study were investigated changes of precipitation behaviour of laves phase in ferrite single phase and ferrite-martensite dual phase and precipitation of laves phase under stress. Hardness changes in ferrite phase appeared two hardness peaks by precipitation of initial fine precipitator and laves phase in 3Mo-0.3Si and 3Mo-0.3Si-C specimens, respectively. Hardness changes in martensite phase of 3Mo-0.3Si-C specimen was lower in the initial stage of aging by carbide precipitation and after this, increased by re-hardening due to precipitation of laves phase. In the ferrite phase, laves phase was mainly precipitated, whereas in the martensite phase, carbide was preferentially formed during the initial stage of aging and with increasing aging time, laves phase and carbide were simultaneously precipitated by precipitation of laves phase at around carbide. In the ferrite-martensite interface, laves phase was mainly precipitated and carbide was mainly formed at boundary of lath martensite than grain boundary. Adding the stress in aging, fine precipitator of inital precipitation of laves phase precipitated in (100) of perpendicular to tensile direction and has grown to only followed<010>direction and also, volume fraction of laves phase increased. Consequently, the stress added was accelerated initial precipitation of laves phase.

• 대한치과교정학회지
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• 제14권1호
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• pp.161-172
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• 1984

This study was undertaken to evaluate the cephalometric changes of the soft tissue and skeletal profile subsequent 10 the rapid palatal expansion in 25 Angle's Class III cases, ranging in age from six to fifteen years, with cross-bite of the anterior teeth, underdevelopment of maxilla and facial disharmony Following results were obtained: 1. ANS moved downward, Point A presented forward & downward movement increasing SNA and Point B presented backward & downward movement decreasing SNB. 2. Mandible was rotated to backward & forward and maxilla moved forward & downward with the bite opening and improvement of anterior teeth cross-bite. 3. Soft tissue on mandible was rotated to backward & forward following hard tissue changes causing the decrease of facial convexity angle and backward & downward rotation of Point B', Pog'. 4. Response of the upper lip was more significant in downward than forward direction, and correlated with the upper central incisor and mandible rotation. 5. Response of the lower lip was more significant in downward than backward direction, and correlated with the mandible rotation. 6. There was a rather high degree of correlation between skeletal profile and soft-tissue profile, 1 : LS, $\bar{1}$:Pog', Pog:LS, Pog:LI, Pog:Pog' in horizontal measurements and $\bar{1}$:Pog', Pog:LI, Pog:Pog' in vertical measurements.

• 복식
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• 제61권7호
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• pp.101-109
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• 2011

The present research aims to suggest the design of a new direction that copes with the changing environment. For example, the design for outdoor wear can be made through various methods that allows it to be worn for anytime and anywhere. Also, the research aimed to seek a development direction of outdoor wear design with environment-friendly expanded function that handles unpredictable environmental changes. The analysis of this research is as follows. First, it can be said that the trend of the outdoor wear design according to climate and environment changes is a design that seeks an efficient and rational role in functional aspects such as complex multi-functionality and minimum decorations as well as enhancing economic efficiency. Second, the outdoor wear design provides the optimal climate for the human body even in a continuously changing artificial environment. Its easy and comfortable function also helps to keep defense from possible risk elements. Lastly, this research seeks interactions among design, the body and environment. It also tries shape change using buttons and zippers, etc. according to expansion of a structural form of clothes as multi-functionality and versatility tools, and seeks a design form that can be reconstructed. The research that geared toward environmental changes should be further progressed in order to produce apparel that have efficient adaptability of any climate situations.

• 경영과정보연구
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• 제7권
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• pp.463-485
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• 2001

Recently junior colleges in Korea have been working to meet changes in industrial and educational surroundings by establishing new departments, integrating and abolishing existing ones, or adjusting departmental quotas. These endeavors need to be based on an analysis of industrial policies, both national and international, and of the industrial trend of the region in which the particular college is located. They also need to take into consideration change in educational policies and the direction of the college's specialization. This study aims to provide some foundation materials for these endeavors. As a result, it has considered changes in industrial and educational surroundings and analyzed the whole spectrum of departments existing at Korean junior colleges, with a focus on business-related ones. In the course it has taken a look at the division system, presently a hot issue regarding the restructuring of the colleges. To summarize, each college offers departments, having taken into consideration its regional, industrial, and educational environments. The result of this study may be utilized by colleges when they establish new departments, integrate and abolish existing ones, and adjust departmental quotas. When they utilize the result, the colleges are advised to consider changes in the structure of industries and manpower, those in educational policies, and the direction of their specialization.