• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.10
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• pp.810-815
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• 2008

To enhance aerodynamic efficiency of the Smart Un-manned Aerial Vehicle(SUAV) during the transition period, wingtip fence is attached at the end of wing. The application of wingtip fence is to reduce the effect of the separated flow caused by the nacelle on the wing especially when the tilting angle of nacelle is more than 30 degrees. To compare the effect of with and without wingtip fence, flow visualization and measurement of the aerodynamic coefficients using the pyramidal type external balance are done. Result of forces and moments measurement shows that the slope of lift coefficient is increased 18% and rolling moment of SUAV especially 60 & 90-degree tilting is changed in favorable manners with wingtip fence.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.11
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• pp.531-535
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• 2002

Nowadays, the most serious problems in ac PDP are high cost and complex manufacturing processes. To solve these problems, fence electrode structure, which eliminates the need for expensive transparent electrodes, has been newly suggested. But it has a lower luminance and luminous efficiency than the conventional stripe type electrode structure. In this study, an improved fence electrode structure has been suggested in order to improve luminance and luminous efficiency. The experimental results show that the luminous efficiency of suggested structure is 25% higher than that of conventional fence electrodes.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.185-188
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• 2008

In this study, we experimentally investigated that the optimization of pulsating jet to reduce the separated flow region behind the vertical fence. The vertical fence was submerged in the turbulent boundary layer in the circulating water channel and we applied phase averaged PIV method to measure the instantaneous velocity fields around the fence. One cycle of pulsating jet is divided into 20 phases and grabbed total 200 instantaneous velocity fields at each phase. The experiments were performed by varying the frequency, maximum jet velocity and the shape of pulsating jet wave. Pulsating jet was precisely made by piston-type pump controlled by the computer. The obtained results were compared with normal fence flow. From this study, we found there is the specific frequency which is effective in reducing the reattachment region.

• IEMEK Journal of Embedded Systems and Applications
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• v.14 no.1
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• pp.43-49
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• 2019

Recently, the importance of industrial fieldbus has been highlighted since the emergence of Industry 4.0. In particular, the Ethernet-based fieldbus protocol is actively used in automation systems. This paper proposes a safety fence system based on EtherCAT, a type of Ethernet-based fieldbus, to measure external loads. In order to measure the external loads, a force sensor was connected to an EtherCAT slave that transmits the sensor data to an EtherCAT master in real-time. The master ultimately controls the angle of the safety fence when it detects danger based on the given data. In the future, more effiecient safety fence system will be developed by using a HMI system to communicate with the EtherCAT master to manage safety and by employing multiple sensors to increase the accuracy of the fence system.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.408-411
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• 2008

In an attempt to enhance luminance efficiency and to reduce discharge delays of test panels with aluminum fence-electrodes, various designs of the electrodes were prepared by chemically etching the aluminum foils bonded to soda-lime glass substrate via anodic bonding process. The effects of fence design on luminance and discharge characteristics were investigated and compared with conventional ac-PDPs. These results showed a possibility of using fence-type aluminum electrode at front plates of ac-PDDs without sacrificing its performance.

• Journal of Korean Association for Spatial Structures
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• v.14 no.2
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• pp.51-58
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• 2014

Meteorological observatories use measuring boards on even ground in open areas to measure the amount of snowfall. However, it is very difficult to evaluate the accurate amount of snowfall because of the effects of the wind. Therefore, this study tried to determine the internal wind flow inside a windbreak fence to identify an area that was not affected by wind in order to measure the snowfall. We performed a computational fluid dynamics analysis, wind tunnel test of the type and height of the windbreak fence, and analyzed the wind flow inside the fence. The results showed that a double windbreak fence was better than a single windbreak fence for reducing the wind velocity. The reduction of the wind velocity was highest in the middle of a windbreak fence with a width of 4 m and a height of 60cm, where the windbreak fences were fixed to the ground.

• Journal of the Korean GEO-environmental Society
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• v.6 no.3
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• pp.35-45
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• 2005

The rockfall protection fence is one of the most common rockfall protection methods in Korea. The typical rockfall protection fence consists mainly of three parts ; H-beam supports, wire meshes, and wire ropes. The design of the rockfall protection fence is made such that the total energy absorbing capacity of the fence. Therefore, resulting from the combined energy absorbing capacity of the three parts is larger than the falling energy of rocks. In present study, a new rockfall protection fence, constructed using expanded metals instead of the existing wire rope and wire mesh for the typical type of rockfall protection fence, was evaluated on its performance by conducting both laboratory and field tests. Also, for a comparison, the same tests were performed on the typical rockfall protection fence. The test results revealed that the expanded material is an economic alternative to the existing protection materials and the expanded metal rockfall protection fence exhibits the higher energy absorbing capacity compared to that of the typical rockfall protection fence.

• Journal of architectural history
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• v.28 no.5
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• pp.7-18
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• 2019

The "Imwon Gyeongjeji(林園經濟志)", the largest encyclopedia of the Late Joseon Dynasty covers the details of the materials and construction methods related to everyday life's facilities. It is very useful to examine the "Imwon Gyeongjeji" for studying the materials and construction methods of the fences in traditional dwellings. Therefore, we tried to find the characteristics of the traditional fences exhibited in the "Imwon Gyeongjeji" by examining the construction methods shown in the book by structure of the fence. The results are as follow. First, the nine types of fence were listed in the "Imwon Gyeongjeji". Second, we could figure out the construction methods according to the structure of fences. The fence is divided into three parts: foundation, body, and roof. The body of the fence is a characteristic part distinguishing the types of fence. The foundation and the roof are related to the durability of the fence, regardless of the type of fence. The "Imwon Gyeongjeji" showed a robust manner in building fences than known today. Third, we found that the introductions and transformations of certain fence types. Fences such as Chuibyong(翠屛), Jeon Doldam(甎墻) and Bunjang were originated from China, yet has developed unique Korean styles in Joseon. It could also be seen that Kajo Zhang(哥窯墻) and Yonglong Zhang(玲瓏墻) were special fence types imported from China. It is not certain that the fences depicted in the "Imwon Gyeongjeji", represent the whole features of Joseon fences, but it is certainly an important literature to understand the structure and design of traditional fences of the Late Joseon Dynasty.

• Journal of Mechanical Science and Technology
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• v.20 no.7
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• pp.1051-1058
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• 2006

The steady aerodynamic characteristics of a wing flying over a channel are investigated using a boundary-element method. The present method is validated by comparing the computed results with the measured data. Compared with a flat ground surface, the channel fence augmented the lift increase and induced drag reduction. When the fence is lower than the wing height, the gap between the wingtip and the fence does not affect the aerodynamic characteristics of the wing much. When the fence is higher than the wing height, the close gap increased the lift. The induced drag is reduced when the wing is placed near the ground or at the same height as the fence. It is believed that present results can be used in the conceptual design of the high-speed ground transporters flying over the channel.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.261-267
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• 2008

One of the most important issues in fence-type PDP is low luminance and luminous efficiency. To improve luminance and luminous efficiency, new sustain electrode structure which contains long discharge gap is necessary. However, it causes rise of firing voltage. In this paper, a new fence electrode structure is proposed in order to solve these problems. To drop the firing voltage, tow hump shaped electrodes is added on the main discharge electrode, and distance between two humps is controlled. The experimental results show that the test panel with the narrow horizontal gap(40um) between two humps shows low firing voltage by 17V compared with 80um gap in spit of similar luminance and luminous efficiency.