• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.55-56
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• 2006

This paper describes a new concept of the robot that can climb on the vertical plane. The engineering design problem of the main structure is presented and the experimental results regarding a new mechanism of climbing on the vertical wall are discussed. The locomotive motion of the robot is realized by using a series chain of two caterpillar wheels on which 24-suction pads are installed. White each caterpillar wheel rotates on the vertical plane surface, the vacuum pads are activated in sequence based on the sequential opening by specially designed mechanical valves. The detail design feature of the valve is also described in this paper. The overall size of the robot is around 460 mm in width and length, respectively, and 200 mm in height. Its mass is slightly over 14 kg. The main mechanical structure of the robot consists of driving motors, vacuum caterpillar system, steering part, vacuum pump and battery. The performance of the robot is verified on the vertical wall.

• The korean journal of orthodontics
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• v.50 no.1
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• pp.42-51
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• 2020

Objective: The objective of this study was to evaluate the effects of cetirizine, a histamine 1 receptor antagonist, on bone remodeling after calvarial suture expansion. Methods: Sixty male Sprague-Dawley rats were divided into 4 groups; the phosphate-buffered saline (PBS)-injected no expansion group, cetirizine-injected no expansion group, PBS-injected expansion group, and cetirizine-injected expansion group, and were observed at 7, 14, and 28 days. Five rats per group were examined at each observation day. Daily injections of cetirizine or PBS were administered to the relevant groups starting 2 weeks prior to expander insertion. A rapid expander was inserted in the calvarial bone to deliver 100 cN of force to the parietal suture. The specimens were prepared for hematoxylin and eosin and tartrate-resistant acid phosphatase (TRAP) staining. Suture opening and bone regeneration were evaluated using microcomputed tomography and bone histomorphometric analysis. Serum blood levels of osteocalcin and carboxy-terminal collagen crosslinks (CTX) were also evaluated. Results: TRAP-positive cell counts and CTX levels decreased while osteocalcin levels increased in the cetirizine-injected expansion group at observation day 28. In the expansion groups, the mineralized area gradually increased throughout the observation period. At day 28, the cetirizine-injected expansion group showed greater bone volume density, greater mineralized area, and narrower average suture width than did the PBS-injected expansion group. Conclusions: Cetirizine injection facilitated bone formation after suture expansion, mostly by suppressing osteoclastic activity. Histamine 1 receptor antagonists may aid in bone formation after calvarial suture expansion in the rat model.

• The Research Journal of the Costume Culture
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• v.18 no.5
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• pp.960-976
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• 2010

Even though Joseon Dynasty strictly identified between military and civil officials, the dress and its ornament have been studied only based on embroidery emblems that are correctly identified between military and civil officials. Thus, this study intends to research the features of the only military officials uniform, Cheollik, different from the civil officials's identifying them with other features shown from the records, unearthed relics, stone statue, Joseon-tongsinsa-haengnyeoldo(Illustration of Joseon Delegation to Japan), etc., and its results are as follows: First, for wearing examples of the military officials, from the facts that they had worn mainly ordinary clothes, etc. on announcement of military service examination. There was no difference between military and civil officials's clothes by Daejeonhusokrok and the other documents, and there was an assertion that the form of the military and civil officials's clothes should be different by the document, Hongjejeonseo, in the latter term of the Joseon Dynasty. It is presumed that length, width and shape of sleeves might have been different. Second, unearthed Cheollik of the military officials are mostly from the 16th~17th centuries and most of them have removable sleeves according to statistics. The skirt had an opening and one or two slits. Various textiles were used. Third, military official statues of high governor wear small caps and helmets. They wear Cheollik with the collars same as the collar of Bangryeong and Jikryeong, which is also called Dopji Cheollik. It would be considered as they wear the Bangryeong on top of the Cheollik. Fourth, militarly officials described on the Joseon-tongsinsa-haengnyeoldo(Illustration of Joseon Delegation to Japan) wear Cheollik, Rip, Donggae, Okro, Hongsadae, Hwando, Deungchae.

• The Korean Journal of Physiology
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• v.11 no.1
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• pp.45-50
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• 1977

This study was undertaken to investigate the effect of cingulate cortical ablation upon gastric ulceration, and the pathway through which cingulate cortex exerts the effect. 56 female rats were divided equally into cingulate (cingulate cortical ablation), cingulate-vagal (cingulate cortical ablation and vagotomy), normal control and vagal (vagotomy) groups. Cingulate cortex was ablated through a slit-shaped opening (1 mm in width, 13 mm in length) which was made symmetrically on both sides of, and parallel to, the sagittal suture by removing a bone flap from parietal and frontal bones on each side. Vagus nerves on both sides were transected around the distal end of the esophagus. In the normal control animals, surgical intervention ended with scalp incision. All rats were kept without restraint or food deprivation for 3 weeks after surgery. The stomach of each rat was inflated with 7 ml of physiological saline and then removed under deep anesthesia. The mucosal surface was examined under dissecting microscope for the location, shape and number of ulcers, and then enlarged photograph $(4{\times})$was taken. The incidence of ulcer in each group was counted and the number of ulceration as well as the total area of glandular mucosa were measured on the photograph. Results obtained were as follows: 1. The mean number of ulcer per stomach and the total area of ulcer exprssed as permillage of the total area of glandular mucosa were significantly higher in the cingulate group than the cingulate-vagal, the normal control and the vagal groups. There was no difference among the latter three groups. 2. The incidence of ulcer in the cingulate group was significantly higher than that in the .normal control group and was also higher, though not significantly, than those in the cingulate-vagal and the vagal groups. There was no difference among the normal control, the cingulate-vagal and the vagal groups. It is inferred from the above results that the cingulate cortex exerts an inhibitory influence upon gastric ulceration and that this influence is mediated by controlling the vagal activity.

• Geotechnical Engineering
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• v.14 no.1
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• pp.93-108
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• 1998

In this study, the analytic solutions and numerical methods were used to estimate the shape and size effects on the stability of underground openings. The stability of underground openings was evaluated by scrutinizing the effects of the rock mass quality, the state of in-situ stresses and the lateral earth pressure coefficient on the displacement, the stress concentration and the plastic region developed in the vicinity of the openings. The analytic solutions have shown that the stress concentration factor is inversely proportional to the radius of curvature of openings. Through parametric study on the various shapes and sizes of underground openings the characteristics of the controlling factors concerned with the stability were analyzed. Then, the study was extended to the horseshoe-shaped openings commonly used for under ground storage. Through the extended study the effects of the stress ratio and the height-towidth ratio of openings on the maximum displacement and plastic region developed around the openings were estimated. The results have shorn that the height-to-width ratio of domestic storage caverns can be increased economically without stability problem, as far as the lateral earth pressure coefficient is appropriate.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.3
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• pp.203-210
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• 2014

In this study, the hydrodynamic characteristics of Weis-Fogh type water turbine were calculated by the advanced vortex method. The wing (NACA0010 airfoil) and both channel walls were approximated by source and vortex panels, and free vortices are introduced away from the body surfaces. The distance from the trailing edge of the wing to the wing axis, the width of the water channel and the maximum opening angle were selected as the calculation parameters, the important design factors. The maximum efficiency and the power coefficient for one wing of this water turbine were 26% and 0.4 at velocity ratio U/V=2.0 respectively. The flow field of this water turbine is very complex because the wing moves unsteadily in the channel. However, using the advanced vortex method, it could be calculated accurately.

• Journal of Biosystems Engineering
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• v.34 no.2
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• pp.95-105
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• 2009

A method was proposed which employed control of the drop location of fertilizer particles on a spinner disc to optimize the spread pattern uniformity. The system contained an optical sensor as a feedback mechanism, which measured discharge velocity and location, as well as particle diameters to predict a spread pattern of a single disc. Simulations showed that the feed gate adaptation algorithm produced high quality patterns for any given application rate in the dual disc spreader. The performance of the feed gate control method was assessed using data collected from a Sulky spinner disc spreader. The results showed that it was always possible to find a spread pattern with an acceptable CV lower than 15%, even though the spread pattern was obtained from a rudimentary flat disc with straight radial vanes. A mathematical optimization method was used to find the initial parameter settings for a specially designed experimental spreading arrangement, which included the feed gate control system, for a given flow rate and swath width. Several experiments were carried out to investigate the relationship between the gate opening and flow rate, disc speed and particle velocity, as well as disc speed and predicted landing location of fertilizer particles. All relationships found were highly linear ($r^2$ > 0.96), which showed that the time-of-flight sensor was well suited as a feedback sensor in the rate and uniformity controlled spreading system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.346-351
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• 2006

본 논문은 콘크리트 표면 균열 영상에서 균열의 특징을 추출하기 위해, 영상 처리 기법을 적용하여 균열의 특징(길이, 폭, 방향)을 자동으로 추출 및 처리 할 수 있는 기법을 제안한다. 본 논문에서 적용된 영상 처리 기법으로는 균열 영상의 빛을 보정하기 위하여 모폴로지 기법인 채움(Closing)기법을 적용한다. 균열의 경계를 명확히 추출하기 위하여 고주파 강화 필터링을 적용한 후, 8가지 색상(검정, 빨강, 파랑, 초록, 노랑, 자주, 주황, 하늘)으로 명암 값을 분류하고 그 중 빈도수가 가장 높은 색상을 가진 명암 값을 제거한 후에 추출한 영상을 이진화한다. 이진화된 영상에서 콘크리트 표면 균열의 실거리 측정을 위한 임의의 선을 제거하기 위하여 위치 히스토그램을 적용하여 임의의 선을 제거한다. 임의의 선이 제거된 균열 영상에서 $5\times5$ 마스크를 적용하여 균열을 확대시키고, 3차례에 걸쳐 잡음 제거연산을 수행하여 균열의 후보 영역을 선택한 후, 후보 영역으로부터 특정 균열들을 추출한다. 추출된 특정 균열을 모폴로지 기법인 제거(Opening) 연산을 수행하여 균열의 특징이 일정하게 유지되게 하고 미세하게 끊어진 부분을 보정하여 균열의 특징(길이, 방향, 폭)을 측정한다. 실제 콘크리트 표면 균열영상을 대상으로 실험한 결과, 특정 균열이 효율적으로 추출되었고, 특정 균열의 길이, 방향, 폭의 등이 정확히 추출 및 계산되었다.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.4
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• pp.271-278
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• 2018

In this study, the conventional cylinder-shaped lower bar on the canvas was modified and its performance was tested to improve the opening force of the stow net on anchor. The improved new lower bar used in the test is consisted of 13 flat bars with a length of 1.8 m, a width of 0.075 m and a thickness of 4 mm, and a pipe with a length of 2.0 m and a diameter of 50 mm. A stow net with the improved lower bar and a stow net with an existing lower bar were installed underwater and their trajectories for 21 hours were examined. To confirm their trajectories, GPS loggers were attached to the buoys on the left and right canvases and the buoy of the hauling rope. As a result of the test, the rotation of the gear with the improved bar was smoother than that with the existing bar. As a result of comparing the changes in the interval of the buoys attached to the canvas after the low and high tide, the buoy spacing of the gear with the improved bar is wider than that of the conventional gear; moreover, the larger the interval, the smoother the rotation of the fishing gear was. Therefore, it is considered that using the improved lower bar can enhance the performance of the stow net.

• Fire Science and Engineering
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• v.32 no.6
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• pp.7-14
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• 2018

This study investigated numerically the influences of fire curtain and natural smoke vent area on smoke movement in the stage fire of a theater using FDS (Fire Dynamics Simulator). The dimension of the theater stage was 31 m in width, 34 m in depth, and 32 m in height. The area ratios between the natural smoke vent and stage were approximately 10%, 8%, 5%, and 1%. The gap distance between the fire curtain and proscenium wall was 0.5 m. The fire curtain and natural smoke vent area were observed to affect significantly the behavior of smoke movement to the auditorium and the mass flow rates of inflow and outflow through the natural smoke vent and proscenium opening. In addition, under the same natural smoke vent area, the pressure in the stage with a fire curtain was lower than that without a fire curtain.