• Wind and Structures
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• 제39권3호
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• pp.175-190
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• 2024

Aerodynamic shape optimization is very useful for enhancing the performance of wind-sensitive structures. However, shape parameterization, as the first step in the pipeline of aerodynamic shape optimization, still heavily depends on empirical judgment. If not done properly, the resulting small design space may fail to cover many promising shapes, and hence hinder realizing the full potential of aerodynamic shape optimization. To this end, developing a novel shape parameterization scheme that can reflect real-world complexities while being simple enough for the subsequent optimization process is important. This study proposes a machine learning-based scheme that can automatically learn a low-dimensional latent representation of complex aerodynamic shapes for bluff-body wind-sensitive structures. The resulting latent representation (as design variables for aerodynamic shape optimization) is composed of both discrete and continuous variables, which are embedded in a hierarchy structure. In addition to being intuitive and interpretable, the mixed discrete and continuous variables with the hierarchy structure allow stakeholders to narrow the search space selectively based on their interests. As a proof-of-concept study, shape parameterization examples of tall building cross sections are used to demonstrate the promising features of the proposed scheme and guide future investigations on data-driven parameterization for aerodynamic shape optimization of wind-sensitive structures.

• 한국자동차공학회논문집
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• 제2권1호
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• pp.9-25
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• 1994

In the present study, the Reynolds-averaged Navier-Stokes equations, together with the equations of the $k-{\varepsilon}$ model of turbulence, were solved numerically in a general body-fitted coordinate system for three-dimensional turbulent flows around the six basic shapes of the magnetically levitated train(MAGLEV). The numerical computations were conducted on the MAGLEV model configurations to provide information on shapes of this type very near the elevated track at a constant Reynolds number of $1.48{\times}10^{6}$ based on the body length. The coordinate system was generated by numerically solving a set of Poisson equations. The convective transport equations were discretized using the finite-analytic scheme which employed analytic solutions of the locally-linearized equations. A time marching algorithm was employed to enable future extensions to be made to handle unsteady and fully-elliptic problems. The pressure-velocity coupling was treated with the SIMPLER-algorithm. Of particular interests were wall effect by the elevated track on the aerodynamic forces and flow characteristics of the six models calculated. The results indicated that the half-circle configuration with extended sides and with smooth curvature of sides was desirable because of the low aerodynamic forces and pitching moment. And it was found that the separation bubble was occured at wake region in near the elevated track.

• 동의생리병리학회지
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• 제20권5호
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• pp.1089-1101
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• 2006

Following conclusions are drawn from study about Yukmigiwhangwon through referring to literatures and reviewing in the point of Hyungsang medicine. Yukmigiwhangwon was prescribed by Jeon Eul in order to cure five kinds of flaccidity of infants, but after since then it has been basically applied to symptoms which was caused by deficiency of the kidney not only infants but also adult. The deficiency of kidney is the lack of vital essence and body fluid stored in kidney, it happens because infants are born in the conditions of lack of receiving in the womb. And it happens because adults infringe the rules of life, especially the sexual life. Main symptoms of the poverty of renal functions are emptiness of the brain marrow, dizziness, forgetfulness, tinnitus, deafness, vertigo and dim eyesight, insomnia, the low back and knees aching and limping, heat on the legs, tibia aching, nocturnal emission, dry mouth, reddened tongue and little coating or non coating of the 'tongue, weak blood meridians. the treating method is nourishing Eum and supplementing kidney. In Dongeuibogam Yukmigiwhangwon is mentioned in the parts of vital essence, blood, voice, kidney, urine, eye, ear, the low back, hair, fire, exhaustion syndrome, cough, polydipsia, infant, etc. The shapes which Yukmigiwhangwon is applied to are the Dam Body Doing deficiency of Eum due to excess of Yang, man, infant, Jung type, Fish group, reverse triangular shape, big headed man, big eared man, big mouthed man, man having prominent cheekbones, man having long waist, man having big hips, man with thick hair or white hair, man with bald on the head, etc. In color it is applied to darkish complexion, flushed tip of the nose, or flushed cheek bones. Through inquiring into the clinical cases on the points of Hyungsang medicine Yukmigiwhangwon is efficacious cure to lumbago, symptoms of tendons and bones, symptoms of eyes and ears, symptoms of respiratory organs, dermatopathia, headache, polydipsia, urinary disorders, etc.

• 동력기계공학회지
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• 제7권3호
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• pp.48-53
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• 2003

This paper deals with the control of a horizontally placed flexible rotor levitated by electromagnets in a multi-input/multi-output (MIMO) active magnetic bearing(AMB) system. AMB is a kind of novel high performance bearing which can suspend the rotor by magnetic force. Its contact-free manner between the rotor and stator results in it being able to operate under much higher speed than conventional rolling bearings with relatively low power losses, as well as being environmental-friendly technology for AMB system having no wear and no lubrication requirements. In this MIMO AMB system, the rotor is a complex mechanical system, it not only has rigid body characteristics such as translational and slope motion but also bends as a flexible body. Reduced order nominal model is computed by consideration of the first 3 mode shapes of rotor dynamics. Then, the $H_{\infty}$ control strategy is applied to get robust controller. Such robustness of the control system as the ability of disturbance rejection and modeling error is guaranteed by using $H_{\infty}$ control strategy. Simulation results show the validation of the designed control system and the modeling method to the rotor.

• 동력기계공학회지
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• 제16권4호
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• pp.17-23
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• 2012

In this study, the numerical simulation and basin model test have been performed to evaluate sea worthiness and resistance performance for a small pre-planning three type of leisure boats which are U, V, Y shapes of hull forms. As a well known commercial CFD code, Maxsurf, was applied for modeling hull forms used as the solver of motion analysis. Also the model resistance test was carried out to estimate the effective power of boat in the basin tank. Numerical simulation and model test results show that Y-shaped hull is better than the other types in terms of heave and pitch motion, having a key effect on a boat sea worthiness. But V-type hull is more efficiency than others cases in resistance performance.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1442-1445
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• 2003

In precision machinery industry, it's required with small size and low noise design to using in constant liquid delivery equipment. To accomplish it's purpose, we designed the check valve with rubber sheet of circle shapes as a possible assembly in pump body. The test equipment for piezoelectric pump was able to test pressure-flow property and output property of piezoelectric pump by variation(magnitude of voltage and frequency) of input power.

• 한국의상디자인학회지
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• 제24권2호
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• pp.117-129
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• 2022

In terms of junior high school girls' growth patterns during early adolescence, unlike childhood when relatively balanced growth patterns are found and high school years in which the normal adult body type is almost reached, junior high school girls display imbalanced and rapid growth. In fact, diverse size changes by body part occur with a significant difference among individuals. Therefore, it has been difficult for junior high school students to select their exact size when buying a school uniform. This study attempted to develop winter blouse and skirt patterns reflecting the latest comfortable and active school uniform trends, using middle school girl avatars of various body shapes. Skirt and blouse pattern-drawing methods and margins differed. Based on such results, research prototypes were prepared. Then, virtual wear prospective drawings, clothing pressure, and appearance were assessed by body shape. Skirts were assessed with 22 factors while blouses were analyzed with 25 factors. Then, correlations between skirts and blouses were analyzed. According to the analysis, the reason why the dart & pleats position and margin were rated low was confirmed. In a virtual wear assessment on skirt patterns by body shape, a significant difference was found in all categories except for position of the hip circumference, margin of the hips, width of the skirt, and appropriateness of waist line position. The virtual wear assessment on the blouse patterns by body shape also revealed a significant difference in all categories but fit and shape pf the back part. In blouses, a significant difference was observed around shoulders and waist in type 1 and around the belly in type 2. On the contrary, for skirts, a significant difference was found around the hips and waists in type 1 and type 2. Therefore, these factors should be considered in making blouses and skirts. The above results suggested that skirt and blouse patterns should vary by body shape. It is anticipated that there should be further studies comparing brand-name school uniforms for high school girls and school uniforms by body shape.

• 대한한의학회지
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• 제27권2호
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• pp.145-154
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• 2006

Objectives : Methods to evaluate obesity are growing to be important in studying links between health and disease. Physicians are using BMI (body mass index) to evaluate obesity, but they can't know how much fat the body has by using that method. Even though there are several assessments, there are different scales, so patients are diagnosed as obese, by some but not by others. These studies are limited in evaluating obesity; it is necessary to study based on new knowledge. According to Oriental Medical Theory, obese people are categorized into 3 types, Fei, Kao and Liu Ren. They have different pathology and body shapes than non-obese people. The relationship between Oriental Medical Theory and BMI and assessment of body fat is a fundamental need to easily approach and treat obesity. Methods : At 00 Oriental Medical Center, 145 female subjects who intended to lose weight were given physical tests and grouped into 5 types of obesity. The physical tests were height measurement, BMI, body composition (body fat mass and lean body mass), skin elasticity and physical strength tests. One-way analysis of variance was done to compare the means of physical tests between the five types of obese women. There was some relationship between characteristics of the five types based on physical tests and Fei, Kao and Liu Ren based on Oriental Medical Theory. Least significant difference (LSD) was used in multiple comparisons. Results : 1. According to the skin elasticity test, obesity type 5 placed between obesity types 3 and 4 and obesity types 1 and 2. Obesity types 3 and 4 were in the low skin elasticity result group; obesity types 1 and 2 were in the high ones (p<0.1).Based on Oriental Medical Theory, Fei Ren and Kao Ren can be distinguished by skin elasticity degree. This result should form the basis of obesity diagnosis. 2. According to Oriental Medical Theory, Fei Ren is smaller than others. Based on height measurement, obesity types 3 and 4 were significantly lower than other obesity types (p<0.1), so there is a relationship between Fei Ren and obesity types 3 & 4. 3. There were significant differences between obesity type 2 and obesity type 4 in the body fat mass result (p<0.1). This study did not have large enough a sample size to distinguish Liu Ren. Conclusions : Further clinical research is necessary to study measurement methods of body shape type and skin elasticity for distinguishing Fei Ren from Kao Ren. The diagnosis and treatment based on the relationship of these types should be studied further.

• 한국의상디자인학회지
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• 제24권3호
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• pp.127-144
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• 2022

This paper aims to analyze the different external images of women expressed in ancient artwork through the socio-cultural background and the aesthetic view during the Tang and Song dynasties of China. The research method contains a literature review involving the collection of historical literature, thesis, and artwork data. The image of women according to the aesthetic view of the two periods is summarized as follows. In terms of face shape, the Tang pursued a round face while the Song pursued a more slender shape. As for hair ornamentation, the Tang wore various shapes of hair buns like "Paojiaji", and decorated them with coronets. The Song wore various types of braided hair called "Tongxinji", but the coronets were smaller and more sophisticated. For makeup, the Tang wore colorful and heavy makeup and the Song makeup was lighter and more elegant. In attire, the Tang followed revealed shape, used splendid colors and thin, transparent material. The Song exhibited a more simple design and was conservative and neat, using luxurious silk fabric with low chroma. In body shape, the Tang pursued the "beauty of obesity" with a voluptuous body shape; the Song pursued the "beauty of gaunt" with a slim body shape. As the result of the analysis according to the aesthetic views of the Tang and Song dynasties, women of Tang were depicted as rich, and women of Song were rather neat. The research on the aesthetic views that changed according to the development of social civilization and the status of women will play an active role in the transmission and development of traditional Chinese culture. At this point, the paper may contribute to the creation of images of women as well as changes in the art of future generations.

• 대한방사선기술학회지:방사선기술과학
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• 제40권1호
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• pp.13-18
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• 2017

본 논문은 GATE (geant4 application for tomographic emission) 시뮬레이션을 이용하여 다양한 모양과 재질의 팬텀에서 CTDI (computed tomography dose index)를 평가하였다. GATE 시뮬레이션은 실린더 기둥, 타원 기둥과 육각 기둥 형태와 물, PMMA (polymethyl methacrylate), polyethylene 그리고 polyoxymethylene 재질의 다양한 지름(1 ~ 50 cm)의 팬텀을 모사하여 $CTD_{I100center}$ 값을 비교하였다. 120 kV, 200 mAs에서 실린더 기둥, 타원 기둥과 육각 기둥의 $CTDI_{100center}$ 값은 각각 11.1, 13.4 그리고 12.2 mGy이었다. 이 결과는 동일 볼륨이지만 팬텀의 형태에 따라 $CTDI_{100center}$ 값의 차이가 있음을 알 수 있다. 그리고 물, PMMA 그리고 polyoxymethylene 팬텀의 $CTDI_{100center}$ 값을 비교했을 때 물질의 밀도가 높을수록 상대적으로 $CTDI_{100center}$ 값이 낮게 측정되었다. 하지만 polyethylene의 경우 지름이 15 cm ($CTDI_{100center}$ : 35.0 mGy) 이 상에서는 PMMA 보다 $CTDI_{100center}$ 값이 증가하였다. 그리고 30 cm ($CTDI_{100center}$ : 17.7 mGy) 이 상의 지름에서는 물 보다 더 높은 $CTDI_{100center}$ 값을 보였다. 본 실험을 통해 팬텀의 재질 및 모양에 따른 $CTDI_{100center}$ 값을 GATE 시뮬레이션을 이용하여 평가하였다. CT 선량 평가시 다양한 재질 및 인체에 가까운 모양의 팬텀을 사용함으로써 좀 더 정확한 환자선량을 평가할 수 있을 것이다.