• International Journal of Aeronautical and Space Sciences
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• 제2권2호
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• pp.1-18
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• 2001

A numerical technique for simulating the separation dynamics of strap-on boosters jettisoned in the dense atmosphere is presented. Six degree of freedom rigid body equations of motion are integrated into the three-dimensional unsteady Navier-Stokes solution procedure to determine the dynamic motions of strap-ons. An automated Chimera overlaid grid technique is introduced to achieve maximum efficiency for multi-body dynamic motion and a domain division technique is implemented in order to reduce the computational cost required to find interpolation points in the Chimera grids. The flow solver is validated by comparing the computed results around the Titan IV launch vehicle with experimental data. The complete analysis process is then applied to the. H-II launch vehicle, the central rocket in japans space program, the CZ-3C launch vehicle developed in China and the KSR-III, a three-stage sounding rocket being developed in Korea. From the analyses, separation trajectories of strap-on boosters are predicted and aerodynamic characteristics around the vehicles at every time interval are examined. In addition, separation-impulse devices generally introduced for safe separation of strap-ons are properly modeled in the present paper and the jettisoning force requirements are examined quantitatively.

• Journal of Astronomy and Space Sciences
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• 제37권1호
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• pp.1-9
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• 2020

Frozen orbit is an attractive option for orbital design owing to its characteristics (its argument of pericenter and eccentricity are kept constant on an average). Solar sails are attractive solutions for massive and expensive missions. However, the solar radiation pressure effect represents an additional force on the solar sail that may greatly affect its orbital behavior in the long run. Thus, this force must be included as a perturbation force in the dynamical model for more accuracy. This study shows the calculations of initial conditions for a lunar solar sail frozen orbit. The disturbing function of the problem was developed to include the lunar gravitational field that is characterized by uneven mass distribution, third body perturbation, and the effect of solar radiation. An averaging technique was used to reduce the dynamical problem to a long period system. Lagrange planetary equations were utilized to formulate the rate of change of the argument of pericenter and eccentricity. Using the reduced system, frozen orbits for the Moon sail orbiter were constructed. The resulting frozen orbits are shown by two 3Dsurface (semi-major, eccentricity, inclination) figures. To simplify the analysis, we showed inclination-eccentricity contours for different values of semi-major axis, argument of pericenter, and values of sail lightness number.

• 한국의류산업학회지
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• 제6권6호
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• pp.749-755
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• 2004

This paper was conducted to compare the methods of women's basic pattern and the problems by analyzing the space between skin and clothing using 3D scanner and thereupon, proposed the solutions. The Bunka pattern of Japan Bunka Women's University(Bunka) and the Secoli pattern of Italy istituto carlo secoli(Secoli) were used. The subject who has nearly the same body size with N type of National anthropometric survey of Korea in 1997 was picked out. In the result of analyzing the space between skin and clothing of each pattern by 3D Scanner, there exist significant differences in the chest and bust parts. The Bunka has more space than the Secoli at bust part, especially between bust points. Because the Bunka has the bust dart which was made from only the bust girth, it couldn't reflect the difference of each human body. Whereas the Secoli has the bust dart which gave a consideration the difference between the bust girth and the chest girth, it has more even space between skin and clothing.

• 한국의류학회지
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• 제21권8호
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• pp.1365-1375
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• 1997

Jacket is the basic formal dress for working women, and one of the most frequently worn by them. It has, however, some problems caused by movement, depending on how well it fits. To improve fitness of jacket, this study compared and evaluated the state of fitness objectively by employing a numerical system in relation with clothing and body. We made three experimental jackets based on the previous jacket patterns and used Moire Photo-graphy to measure the amounts of space between clothes and body from the overlap cross section map. The results obtained from this study were summarized as follows; 1. According to the measurement result of the pattern by using the One-dimension measurement, the amount of ease in girth item for pattern B was larger than the other two patterns. The amounts of space of each part showed the difference of the positions of princess lines, and the different sizes of the darts. 2. From the result of Moire Photography, the wearing shapes of the experimental jackets were influenced by the characteristics of somatotype. In addition, we could analyze the differences of the patterns with Moire Photography. 3. The amounts of space for waist part was larger than those for other parts. Pattern B scored the largest amount of space for all parts compared with pattern A and C. 4. For only waist part, there existed a significant difference in the average amount of space for the three patterns.

• 한국실내디자인학회논문집
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• 제16권2호
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• pp.339-346
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• 2007

This thesis has purpose of explaining that light is not only appreciated but also physically percepted in contemporary space design and examining effects of space experience through the physical perception. In keeping with such developments, light has been perceived as the object of another architectural tool in modern space design and has provided men with new experience by providing space image and function different from previous ones. With the expansion of the area of light, light has changed a space that is not a simple architectural factor into the essential concept that gives the architectural space image ! by combining it with architectural space, structure, form and materials throughout the whole process from the beginning to the completion. Through phenomenological approach, light is percepted and experienced by body movement, intervention of senses and memories, and passing of time. The percepted and experienced light brings increase of mutual understanding in space, activation and continuance of user's sensation, recreational experience by event occurrence and space experience effect thorough information from media.

• International Journal of Aeronautical and Space Sciences
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• 제11권3호
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• pp.240-245
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• 2010

The controller of a model reference adaptive control monitors the plant's inputs and outputs to acknowledge its characteristics. It then adapts itself to the characteristics it encounters instead of behaving in a fixed manner. An important part of every adaptive scheme is the adaptive law for estimating the unknown parameters on line. A more precise model is required to improve performance and to stabilize a given dynamic system, such as a satellite in which performance varies over time and the coefficients change due to disturbances, etc. After model identification, the robust controller ($H{\infty}$) is designed to stabilize the rigid body and flexible body of a satellite, which can be perturbed due to disturbance. The result obtained by the $H{\infty}$ controller is compared with that of the proportional and integration controller which is commonly used for stabilizing a satellite.

• 한국실내디자인학회논문집
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• 제12호
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• pp.100-108
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• 1997

A human body can be called the scale of all things and the most perfect and sensual presentation of form. Its beautiful proportion has been used as the most important measure of all the natural organic beings. The attitude of research based on the human scale is so traditional both in East and West, and especially in the field of architecture. It has been the ground of most standards in various buildings and cities from the ancient times. This study aims to examine the way the human body has been investigated in history and to find out how it is applied and expressed as the scale in architecture or interior spaces. It takes a step forward from mere research of proportion by studying even the emotional and psychological relations between space and human beings. It may contribute to the creation of the space for human beings.

• 대한두경부종양학회지
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• 제30권1호
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• pp.28-30
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• 2014

Foreign bodies in upper aerodigestive tract migrating into retropharyngeal space are rarely encountered emergent cases in otolaryngologic fields. A 60-years-old female presented throat pain and lump sense after a meal. Computer tomography showed metallic foreign body impacted in the retropharyngeal space. A hypopharyngeal perforation was suspected by through flexible laryngoscopy and gastrointestinal endoscopy. It was successfully removed by external cervical approach, and we report this case with a review of the related literatures.

• 한국항공우주학회지
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• 제40권2호
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• pp.101-107
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• 2012

본 연구에서는 CFEM을 이용하여 구속조건이 있는 다물체의 운동방정식해석 프로그램을 개발하였다. 다양한 구속조건을 다루기 위하여 7개의 구속모델이 적용되었다. 구속조건으로 보안된 운동방정식은 높은 정확도를 위해 4차의 Runge-Kutta 방법을 사용하여 해석하였다. 다양한 구속조건이 있는 문제에 대하여 개발된 프로그램을 적용하고, 발표된 결과와 비교함으로써 개발 프로그램을 검증하였다.

• 한국항해학회지
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• 제18권4호
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• pp.11-21
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• 1994

Final aim of this paper is a study on simulation of automatic steering of a ship in random seas. In order to achieve this aim, we need excitation due to random seas. The excitation may be estimated from energy spectrum of irregular waves and response functions of manoeuvring motion of a ship in regular waves. This paper deals with response functions of manoeuvring motion of a ship in regular waves. We discussed New Strip Method(NSM) of sway-yaw-roll coupled motions in regular waves. NSM is defined in space axes system and that has been used to predict seakeeping performance of a ship in waves. But ship manoeuvring is defined in body fixed axes system. So we cannot use NSM theory itself in predicting manoeuvring performance of a ship in waves. We introduced relationship between space axes system and body fixed axes system. And we developed modified NSM which was defined in body fixed axes system and was able to be used in manoeuvring motion of a ship in waves. We calculated sway and yaw response functions of manoeuvring motion of a bulk carrier in regular waves.