• International Journal of Aeronautical and Space Sciences
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• v.15 no.3
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• pp.335-343
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• 2014

An airbag is an important safety system and is well known as a safety system in cars during an accident. Airbag systems are also used as a shock absorber for UAVs to assist with rapid parachute landings. In this paper, the dynamics and gas dynamics of five airbag shapes, cylindrical, semi-cylindrical, cubic, and two truncated pyramids, were modelled and simulated under conditions of impact acceleration lower than $4m/s^2$ to avoid damage to the UAV. First, the responses of the present modelling were compared and validated against airbag test results under the same conditions. Second, for each airbag shape under the same conditions, the responses in terms of pressure, acceleration, and emerging velocity were investigated. Third, the performance of a pressure relief valve is compared with a fixed-area orifice implemented in the air bag. For each airbag shape under the same conditions, the optimum area of the fixed orifice was determined. By examining the response of pressure and acceleration of the airbag, the optimum shape of the airbag and the venting system is suggested.

• Journal of the Korean Institute of Landscape Architecture
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• v.29 no.3
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• pp.1-9
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• 2001

The purpose of this article is to study the design and construction of Anap pond with a comparative study of ancient palace ponds in Korea, China and Japan. Anap pond was excavated in 1975-6 and is the oldest orignal pond to be found among Koran garden sites. Anap pond was made just before Shilla drove out Tang, after Shilla ruined Paekjae and Koguryo with the Tang army. This was a time Shilla enjoyed a multi-cultural situation due to interaction with Paekjae and Koguryo refugees, as well as information provided by the ambassadors sent to Tang who were well aquainted with Tang culture. Anap pond shows the influence of not only the indigenous mountain-god myth, but also the theoretical background common among Korea, China and Japan. But it also depicts the special form of space inbued with the exquisite aesthetic taste of Shilla people, which started with Anap pond hardened in Gaen temple, and which bloomed in Sukgulam. Scenery structure analysis gives a supposition of the center building on the western coatland, and sequential analysis gives the feeling of being at sea, analysised by root square shape analysis, equal ratio square shape and golden section, sow we can see the planned space organization by speculated planning. Thus, Anap pond is a garden of Shilla in which the cultural exchange has been inculturated and made our own, and the special aesthetic taste embodied.

• Journal of KIISE:Software and Applications
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• v.32 no.11
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• pp.1013-1020
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• 2005

This paper presents an effective and robust leaf image retrieval system based on shape feature. Specifically, we propose an improved MPP algorithm for more effective representation of leaf images and show a new dynamic matching algorithm that basically revises the Nearest Neighbor search to reduce the matching time. In particular, both leaf shape and leaf arrangement can be sketched in the query for better accuracy and efficiency. In the experiment, we compare our proposed method with other methods including Centroid Contour Distance(CCD), Fourier Descriptor, Curvature Scale Space Descriptor(CSSD), Moment Invariants, and MPP. Experimental results on one thousand leaf images show that our approach achieves a better performance than other methods.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.1
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• pp.73-80
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• 2012

It is important to design the optimal shape in the initial process because the influences on the design and construction are large according to the shape and pattern of spatial structures. However, the existing optimal shape designs for spatial structure are performed by the designer's intuition and experiences. Therefore, this study proposes the integrated process using the topology optimization and cellular automata model. First, the initial optimal shapes are obtained by using the topology optimization, and then the spatial truss structural patterns are created through the application of cellular automata rules. Finally, the optimal shapes to satisfy the various design conditions are generated by the structural analysis and size optimization.

• Journal of the Korea Society of Computer and Information
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• v.13 no.1
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• pp.117-124
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• 2008

We suggest CBIR(Content Based Image Retrieval) method using color and shape information. Using just one feature information may cause inaccuracy compared with using more than two feature information. Therefore many image retrieval system use many feature informations like color, shape and other features. We use two feature, HSI color information especially Hue value and CSS(Curvature Scale Space) as shape information. We search candidate image form DB which include feature information of many images. When we use two features, we could approach better result.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.1
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• pp.58-63
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• 2012

In general, a conventional flap on an aircraft wing can reduce the aerodynamic efficiency due to geometric discontinuity. On the other hand, the aerodynamic performance can be improved by using a shape-morphing wing instead of a separate flap. In this research, a new flap morphing mechanism that can change the wing shape smoothly was devised to prevent aerodynamic losses. Moreover, a prototype wing was fabricated to demonstrate the morphing mechanism. A shape memory alloy (SMA) wire actuator was used for the morphing wing. The specific current range was measured to control the SMA actuator. The deflection angles at the trailing edge were also measured while various currents were applied to the SMA actuator. The trailing edge of the wing changed smoothly when the current was applied. Moreover, the deflection angle also increased as the current increased. The maximum frequency level was around 0.1 Hz. The aerodynamic performance of the deformed airfoil by the SMA wire was analyzed by using the commercial program GAMBIT and FLUENT. The results were compared with the results of an undeformed wing. It was demonstrated that the morphing mechanism changes the wing shape smoothly without the extension of the wing skin.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.2
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• pp.131-139
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• 2003

Shape descriptors play an important role in systems for object recognition, retrieval, registration, and analysis. Seven well-known descriptors including MPEG-7 visual descriptors arebriefly reviewed and a new robust pattern recognition descriptor is proposed. Performance comparison among descriptors are presented. Experiments show that the newly proposed descriptor yields better performance results than Fourier, invariant moment, and edge histogram descriptors.

• Korean Institute of Interior Design Journal
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• v.20 no.4
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• pp.92-100
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• 2011

Under social changes focusing diversification, human-oriented ecological values and emotional and pscyhological satisfaction have been considered more important in space. Such trend has developed into interest in the effect of architectural space and shape on human perception and consciousness, and space has been considered as interactive in ecological, psychological and behavioral, and aesthetic terms rather than physical environment. In particular, exhibition space where interactive sympathy between environment and users through emotional experiences is more important, can have appropriate interaction through intended relationships between environment and humans in space. Therefore, this study aims to understand affordance, an internal mechanism of space recognition and human behaviors. Then it analysed representative types of exhibition space for emotional experiences as a characteristic of affordance Based on the results analysed, it is expected that introduction of affordance as real information in space will be helpful for effective connection of space with human emotional experiences.

• Journal of Astronomy and Space Sciences
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• v.32 no.3
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• pp.269-279
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• 2015

Future space missions will have larger telescopes in order to look deeper into space while improvising on spatial resolution. The primary mirrors for these telescopes will be so large that using a monolithic mirror will be nearly impossible because of the difficulties associated with its fabrication, transportation, and installation on a launch vehicle. The feasibility of launching these huge mirrors is limited because of their small launch fairing diameter. The aerodynamic shape of the fairing requires a small diameter, but the height of the launch vehicle, which is available for designers to utilize, is larger than the fairing diameter. This paper presents the development of an axial deployment mechanism based on the screw jack principle. The mechanism was designed and developed, and a prototype was constructed in order to demonstrate a lab model.

• Korean Institute of Interior Design Journal
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• v.21 no.5
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• pp.77-84
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• 2012

Single formative language created by the standardization of industrial society carries a cell constructive aspect. Such space structural form made gigantic buildings, which has a symbolism as an independent object. Such space shows a morphological symbolism by public preference but it did not establish essential meaning of a shape or concentrated relation. In this regard, this paper tries to show organic similarity of structural formality of small commercial space (patterned space), which was made by the continuity of concentrated patterns not an object of dualistic unit features. Therefore, this study analyzed the cultural, commercial and public space based upon systematical concept and features. Systematical space formality that makes multilateral relation between human, environment and a thing is a concentrated view point by relational features not by the cluster displayed by hierarchical features. Systematical space of small patterned space emphasized its appropriateness of expansion and creating diversified spaces unlike gigantic symbolic buildings.