• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.24 no.5
• /
• pp.733-743
• /
• 2000

We solve the integral representation of the Navier-Stokes equations in a lagrangian view by tracking the particles, which have vortex strengths. We simulate the unsteady viscous flow around an impulsively started cylinder using the vortex particle method. Particles are advanced via the Biot-Savart law for a lagrangian evolution of particles. The particle strength is modified based on the scheme of particle strength exchange. The solid boundary satisfies the no-slip boundary condition by the vorticity generation algorithm. We newly modify the diffusion scheme and the boundary condition for simulating an unsteady flow efficiently. To save the computation time, we propose the mixed scheme of particle strength exchange and core expansion. We also use a lot of panels to ignore the curvature of the cylinder, and not to solve the evaluation of the surface density. Results are compared to those from other theoretical and experimental works.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.4
• /
• pp.517-524
• /
• 2007

This paper presents a global localization method using circular correlation of an omni-directional image. The localization of a mobile robot, especially in indoor conditions, is a key component in the development of useful service robots. Though stereo vision is widely used for localization, its performance is limited due to computational complexity and its narrow view angle. To compensate for these shortcomings, we utilize a single omni-directional camera which can capture instantaneous $360^{\circ}$ panoramic images around a robot. Nodes around a robot are extracted by the correlation coefficients of CHL (Circular Horizontal Line) between the landmark and the current captured image. After finding possible near nodes, the robot moves to the nearest node based on the correlation values and the positions of these nodes. To accelerate computation, correlation values are calculated based on Fast Fourier Transforms. Experimental results and performance in a real home environment have shown the feasibility of the method.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.30 no.2
• /
• pp.46-63
• /
• 2012

The object of this study was to analyze the speciality of Korean traditional waterscape and unique landscape formed with reflection of the phases of the time sat the area of Juhabru(宙合樓) in Changdeok Palace as a basic research to find the prototype of Taeaek pond at Changdeok Palace and restoration of the palace. Originally, Taeaek pond at Changdeok Palace was constructed in KingInjo(仁祖) period as a name of Yongji(龍池), later it called Taeaek pond after King Sukjong(肅宗). There is an island as a symbol of the immortal isle, and Chungseojeong(淸署亭), Taiksujae(澤水齋) and Buyongjeong(芙蓉亭) which were built to view the waterscape in Taeaek pond. Buildings were built asymmetrical balance around Taeaek pond because of the morphological character of tetragonal pond. Arrangement of this area has a definite form of axial structure. Yeolgokwan(閱古觀) Gaeyuwa(皆有窩), pavilions, bridges, islands, Osumoon(魚水門) and Juhabru are located on the north and south axis, and island and Osumoon play a role as a intersection and form an east of west axis. In this study, manual of construction for an island and pavilions is provided by analyzing transformational process of island and pavilions at Taeaek pond. Furthermore, kings and officials used to statically enjoy the view around Taeaek pond area, but dynamic fishing and boating activity happened in King Jungjo(正祖) period. These historical backgrounds have an influence on the spatial organization of Taeaek pond. For instance, bridge between Taeaek pond and island was destroyed with the increase of the importance of boating. Symbolic structure around Taeaek pond means 'fish changes to dragon' and 'both of king and officials become one'. Taiksujai, carving fish, Osumoon and Juhabru are provided as a related spatial factors.

• Journal of Digital Contents Society
• /
• v.19 no.4
• /
• pp.605-613
• /
• 2018

In this paper, we propose a system to walk around the world with virtual reality technology. Although the virtual reality users are interested in the virtual travel contents, the conventional virtual travel contents have limited space for experiencing and lack of interactivity. In order to solve the problem of lack of realism and limited space, which is a disadvantage of existing contents, this system created a virtual space using Google Street View image. Users can have realistic experience with real street images, and travel a vast area of the world provided by Google Street View image. Also, a virtual reality headset and a treadmill equipment are used so that the user can actually walk in the virtual space, which maxmizes user interactivity and immersion. We expect this system contributes to the leisure activities of virtual reality users by allowing natural walking trip from famous tourist spots to even mountain roads and alleys.

• Korean System Dynamics Review
• /
• v.13 no.3
• /
• pp.47-66
• /
• 2012

This paper aims at investigating and identifying the factor that has led the back and forth relationship between China and the United States since 1989. Previous studies on this subject addressed the issue by taking either of two approaches: one with the micro view that interprets the back and forth relationship in the context of the end of the Cold war, on other hand, with the macro view that interprets the fragile relationship in the context of the rise of China. However, neither of the approaches explains with sufficiency the question at hand. Hence for the inquiry, this article suggests a fresh view by exploring alternative method of using a cognitive map of each nation's leader, Jiangzemin and Bill Clinton. This article provides an empirical analysis through the Selected works of Jiangzemin and the speeches of Bill Clinton in 1998 for the first time in the field of Sino-US relationship studies in Korea. With the results of the cognitive map analysis, we can reach the following four points. Firstly, indicators of the forth relationship between China and the US are: i) the recognition by Bill Clinton on the importance of China's economic growth and; ii) the US's cooperation of science technology with China. Second, the conflict between China and the US results from the discordance of opinions on the matter of human rights and military power. Second, the conflict will inevitably arise on environmental issues around the globe including a global warming. Third, while China has yet to find a legitimate reason to agree upon these issues with the US, the US urges China of its cooperation. Lastly, Both China and the US attach great importance to the alliance with Japan. This implicates that relatively, issues involving Japan take more control in the China-US relationship, than those of Korea Peninsula.

• The Research Journal of the Costume Culture
• /
• v.9 no.5
• /
• pp.700-711
• /
• 2001

The purpose of this study was to investigate the differences in the method of patternmaking, difficult in draft of patternmaking, fit in sleeve, aesthetic view, fashionableness in the five types of two-piece sleeve under the controled situation. Five types of two piece sleeve that were originated from five countries including domestic companies which called A type, B type, C type, D type, and E type were used. In order to conduct the experiment fur the study, 10 persons who were well organized about the patternmaking drafted 5 types of sleeve and were tested for the differences in the method of patternmaking, difficulty in draft of patternmaking. Another panel were tested for fit in sleeve, aesthetic view, fashionableness in the five types of two-piece sleeve in jacket under the controled situation. The results of this study were as followed 1. C type was needed height of armhole in bodice and D type was needed height of armhole and width of armhole in bodice as well as all parts of sleeve measurements to draft patternmaking. 2. There were significant differences of the items such as cap height, ease amount around sleeve cap, width of sleeve, forwardness of sleeve and the length of elbow line of the five types patternmaking drafted. 3. There were significant differences of difficulty in draft of the five types of patternmaking. C type and E type were easier to draft. 4. There were significant differences in fitness of the sleeves in jacket. C type and E type were more fit. 5. There were significant differences in aesthetic view. A type, B type and E type were more aesthetic under the situation. 6. There were significant differences in fashionableness in jackets. A type and E type were more fashionable under the situation.

• The Journal of Korea Robotics Society
• /
• v.15 no.3
• /
• pp.293-300
• /
• 2020

The purpose of our sensor system is to transparentize the large hydraulic manipulators of a six-ton dual arm excavator from the operator camera view. Almost 40% of the camera view is blocked by the manipulators. In other words, the operator loses 40% of visual information which might be useful for many manipulator control scenarios such as clearing debris on a disaster site. The proposed method is based on a 3D reconstruction technology. By overlaying the camera image from front top of the cabin with the point cloud data from RGB-D (red, green, blue and depth) cameras placed at the outer side of each manipulator, the manipulator-free camera image can be obtained. Two additional algorithms are proposed to further enhance the productivity of dual arm excavators. First, a color correction algorithm is proposed to cope with the different color distribution of the RGB and RGB-D sensors used on the system. Also, the edge overlay algorithm is proposed. Although the manipulators often limit the operator's view, the visual feedback of the manipulator's configurations or states may be useful to the operator. Thus, the overlay algorithm is proposed to show the edge of the manipulators on the camera image. The experimental results show that the proposed transparentization algorithm helps the operator get information about the environment and objects around the excavator.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37A no.9
• /
• pp.786-791
• /
• 2012

This paper presents a depth boundary sharpening method for improved view synthesis in 3D video. In depth coding, distortion occurs around object boundaries, degrading the quality of synthesized images. In order to encounter this problem, the proposed method estimates an edge map for each frame to filter only the boundary regions. In particular, a window-based filter is employed to choose the most reliable pixel as the replacement considering three factors: frequency, similarity and closeness. The proposed method was implemented as post-processing of the deblocking filter in JMVC 8.3.Compared to the conventional methods, the proposed method generated 0.49 dB PSNR increase and 16.58% bitrate decrease on average. The improved portions were subjectively confirmed as well.

• 한국해양학회지
• /
• v.27 no.4
• /
• pp.324-331
• /
• 1992

Water masses and circulations around Korean peninsula are briefly described based on recent studies. The results of theses studies are discussed from the physical point of view. Oceanic conditions in this region are largely due to the roles played by the Tsushima Warm Current, an onshore extension of the Kuroshio, and local conditions such as wind, surface heat flux and fresh water input etc. To the south and west of Korea, the northern/western border of the Tsushima Warm Current Water is roughly the line joining Taiwan and Cheju island. In summer, it is affected by large amount of fresh water discharged from the Changjiang and in winter, an intrusion of this water into the Yellow Sea is induced by the prevailing northwesterly monsoon wind. To the east of Korea, the Tsushima Warm Current Water presents roughly south of the line joining the wast coast of Korea near 37-38$^{\circ}$N and Tsugaru-Soya Straits in the northern Japan. But this situation, together with those in deeper layers, may greatly be changed by winter atmospheric conditions (wind and surface heat flux). The seas around Korea are not yet physically well understood and many problems wait physical explanations. Some problems, along with personal views of them, are mentioned.

• Journal of Korea Port Economic Association
• /
• v.24 no.4
• /
• pp.385-406
• /
• 2008

This study aims to contribute regional economic development by means of searching port logistics industry activation scheme of Gangwon province which has locational advantage around the East Sea Region. Thus, this thesis was provided the port logistics industry activation schemes of that region in the point of local and government view. In the local government level, this study was provided the selection of a key port and its intensive development, establishment of port networking among major port and e-port system of this region, and enlargement of the FTA etc. Also this study was required the relative industry invitation and upbringing, and intensive port logistics marketing activity. On the other hand, in the government level, it needs larger SOC investment for enlargement of direct accessibility and connection to the Gangwon-do ports, and required the intensive and efficient support. Finally, it was proposed the establishment of the total logistics expert education system.