• Journal of Navigation and Port Research
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• v.38 no.1
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• pp.19-27
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• 2014

When a ship operates in a shallow water and channel, the hull sinkage and asymmetrical force generated around the ship by the influence of sea bottom and bank walls are caused collision with sea bottom, other ships or the bank itself. Especially, the shipping company and pilots navigating the area of Europe and North America with many channels are deal with it as a important matter to prevent collision. In this paper, hydrodynamic force generated between the ship and bank using the numerical analysis for the safe navigation of ship, that is, sway force and yaw moment should be presumed qualitatively. It makes a program for fluid analysis of the shallow water and bank effect. Analyses are carried out for three kind of parameter, that is, ship's speed, water depth and ship-bank distance for crude oil carriers. The numerical analysis results are compared with results of the experiments and the previous published papers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2324-2329
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• 2014

The inspection of distance to go train control system conducted only when train is in main line or inspecting line, that affects low work efficiency and hazard elements to safe operation. Before or after train operation, the interface test between on-board and wayside signal system must be conducted. In this paper, onboard signal interface inspection system based on the real-time automatic analysis of onboard system status information that is transmitted to the wayside system and the operation status check of the onboard signal device operates as a virtual train information that is transmitted to the onboard system have been proposed. And after building the inspection system to the inspecting track of Daejeon Subway Line 1, Panam Depot, the verification algorithm of proposed interface test and the results was presented. therefore, it has enhanced work efficiency to do not carry train operation of a half hour in test line to test on-board system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5525-5533
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• 2012

Because of ultra-high buildings or deeper underground space, recent buildings have the potential that people who have lack of physical strength collapse before arriving at the emergency exits when catastrophes occur. In case of fire, the way to escape is that first, people take the stairs of the adjacent areas and then use the elevator to the remaining distance by road to escape notice or be safe. For this reason, the skyscrapers guidelines of Seoul for information on the elevator for evacuation has been established. Nevertheless, when designing buildings to install a elevator for evacuation separately is not effective, so passenger elevators installation according to the criteria are encouraged to use as evacuation elevators. However, this does not include detailed design guidelines so far. Therefore, this study was to investigate design method to use the passenger elevator for evacuation according to the domestic law and international installation criteria, and to calculated number of lifts and refuge to use the elevator using by the ELVAC+ and PathFinder evacuation program.

• Journal of the Ergonomics Society of Korea
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• v.31 no.2
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• pp.397-406
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• 2012

Objective: The aim of this study is to determine legible Korean font sizes within in-vehicle information systems(IVISs) in diving conditions. Background: Font legibility within IVISs is one of important causes on its' safe operations during driving. Several researches proposed some guidelines on the legible English font sizes within IVISs. On the contrary, appropriate Korean font sizes have been hardly known in spite of the typological differences between English and Korean. Therefore, more systematic researches for improving the legibility on Korean font size within IVISs have been required. Method: In this study, an experiment was performed with the following experimental factors: the existence of vibration, the color contrasts(white on black, black on white), the font types(HDR, CubeR, Gothic), and the font sizes(6, 8, 10, 12, 14, 16, 18, 20, 22, 24pt). To fit the experimental conditions into real driving environments, the illuminance was controlled to 15lx by using LED lamp and the distance between IVIS and participants was kept to 70cm. Moreover, all participants took the shutter glasses for employing well-known occlusion techniques. Results: The experimental results showed that 'HDR' and 'Non-vibration + Black on white' group took the shortest response time, and decreasing slopes of the response time with increasing font sizes were slowing down at 14pt then flattened out at 22pt regardless of the existence of vibration and color contrasts. Conclusion: The minimum size for legible Korean font would be about 14pt(5.47mm) and the optimum size would be about 22pt(8.59mm). Application: The guideline on the Korean font sizes from this study will be applied to design an IVIS in the future.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.2 s.5
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• pp.75-83
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• 2004

July 1, 2004 Seoul Metropolitan city is operating the Median Bus Lane System on Gangnam Main Street, Seongsan-Susaek-ro (Road) and Dobong- Mia-ro (Road) as one of the systematic reorganizations in public transportation. It has been assumed that there was an improvement in the speed of bus considering that the Median Bus Lane System practiced on Cheonho-daero (Main Street) since 1996 have had 35km/h on the average. If the Median Bus Lane goes into effect, there is a problem with the left turn on the crossroad. The buses go on the existing first lane so that the left fuming cars cannot help but turn left on the second lane. In case that the Median Bus Lane is put into practice, the left turn on the crossroad should not be allowed. However, if the left turn is not permitted on the crossroads in the aforementioned main streets, neighboring residents will complain about it and there will be some difficulties in finding other detour. On the premise that the prevalent left turn on the crossroads is allowed while the Median Bus Lane is being put into practice, this study suggests the separation of a stop line between buses and other vehicles as a way of fuming left in a safe manner and a way to calculate the appropriate distance.

• Archives of Plastic Surgery
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• v.42 no.4
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• pp.446-452
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• 2015

Background Various techniques are used for performing breast reduction. Wise-pattern and vertical scar techniques are the most commonly employed approaches. However, a vertical scar in the mid-lower breast is prominent and aesthetically less pleasant. In contrast, a semicircular horizontal approach does not leave a vertical scar in the mid breast and transverse scars can be hidden in the inframammary fold. In this paper, we describe the experiences and results of semicircular horizontal breast reductions performed by a single surgeon. Methods Between September 1996 and October 2013, our senior author used this technique in 38 cases in the US and at our institution. We used a superiorly based semicircular incision, where the upper skin paddle was pulled down to the inframammary fold with the nipple-areola complex pulled through the keyhole. Results The average total reduction per breast was 584 g, ranging from 286 to 794 g. The inferior longitudinal pedicle was used in all the cases. The average reduction of the distance from the sternal notch to the nipple was 13 cm (range, 11-15 cm). The mean decrease in the bra cup size was 1.7 cup sizes (range, a decrease of 1 to 3). We obtained very satisfactory results with a less noticeable scar, no complication such as necrosis of the nipple or the skin flap, wound infection, aseptic necrosis of the breast tissue, or wound dehiscence. One patient had a small hematoma that resolved spontaneously. Conclusions This technique is straightforward and easy to learn, and offers a safe, effective, and predictable way for treating mammary hypertrophy.

• Archives of Plastic Surgery
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• v.43 no.6
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• pp.564-569
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• 2016

Background Alar retraction is a challenging condition in rhinoplasty marked by exaggerated nostril exposure and awkwardness. Although various methods for correcting alar retraction have been introduced, none is without drawbacks. Herein, we report a simple procedure that is both effective and safe for correcting alar retraction using only conchal cartilage grafting. Methods Between August 2007 and August 2009, 18 patients underwent conchal cartilage extension grafting to correct alar retraction. Conchal cartilage extension grafts were fixed to the caudal margins of the lateral crura and covered with vestibular skin advancement flaps. Preoperative and postoperative photographs were reviewed and analyzed. Patient satisfaction was surveyed and categorized into 4 groups (very satisfied, satisfied, moderate, or unsatisfied). Results According to the survey, 8 patients were very satisfied, 9 were satisfied, and 1 considered the outcome moderate, resulting in satisfaction for most patients. The average distance from the alar rim to the long axis of the nostril was reduced by 1.4 mm (3.6 to 2.2 mm). There were no complications, except in 2 cases with palpable cartilage step-off that resolved without any aesthetic problems. Conclusions Conchal cartilage alar extension graft is a simple, effective method of correcting alar retraction that can be combined with aesthetic rhinoplasty conveniently, utilizing conchal cartilage, which is the most similar cartilage to alar cartilage, and requiring a lesser volume of cartilage harvest compared to previously devised methods. However, the current procedure lacks efficacy for severe alar retraction and a longer follow-up period may be required to substantiate the enduring efficacy of the current procedure.

• Journal of radiological science and technology
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• v.41 no.4
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• pp.289-295
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• 2018

When using a mobile X-ray unit, primary radiation creates medical images and secondary radiation scatters in many directions, which reduces image quality and causes exposure to patients, care givers and medical personnel. The purpose of this study was to develop a radiation shielding system for effectively shielding secondary radiation and evaluate its effectiveness. Using a mobile X-ray unit, spatial dose according to presence of human equivalent phantom and spatial dose using the developed shielding device were measured, and the phantom at 80 cm equidistance from center of X-ray was compared with spatial dose according to use of a shield. Measurements were taken at intervals of 10 cm every $30^{\circ}$ from the head direction($-90^{\circ}$) to the body direction($+90^{\circ}$). In the spatial dose measurement with and without the phantom, when the human equivalent Phantom was used, the spatial dose was increased by 40% in all directions from 40 cm to 100 cm from the central X-ray, and about 88% of the space dose was reduced when using the developed shields with the phantom. The equidistance dose at 80 cm from the central X-ray was increased by 39% from $5.1{\pm}0.26{\mu}Gy$ to $7.1{\pm}0.15{\mu}Gy$ when the human equivalent phantom was used, and when phantom was used and shielding was used, the spatial dose was reduced by about 90% from $7.1{\pm}0.15{\mu}Gy$ to $0.7{\pm}0.07{\mu}Gy$. The spatial dose of natural radiation was measured to be about $0.2{\pm}0.04{\mu}Gy$ when using the developed shielding with Phantom at a distance of 1 m or more. It is expected that by using the developed shielding system, it will be possible to effectively reduce secondary radiation dose received in all directions and to ensure safe imaging.

• Journal of Electrical Engineering and Technology
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• v.7 no.5
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• pp.765-771
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• 2012

$SF_6$ gas has been used as arc quenching and insulating medium for high and extra high voltage switching devices due to its high dielectric strength, its excellent arc-quenching capabilities, its high chemical stability and non toxicity. Despite of its significant contributions, the gas was classified as one of the greenhouse gas in the Kyoto Protocol. Thus, many researches are conducted to find out the replacement materials and to develop the $SF_6$ gas useless electrical equipment. This paper describes experiments on the temperature change-related breakdown characteristics of $SF_6$ gas ($SF_6$) and $SF_6$ liquid ($LSF_6$) in a model GIS(Gas-Insulated Switchgear) chamber in order to show the possibility of more stable and safe usages of $SF_6$ gas. The breakdown characteristics are classified into three stages, namely the gas stage of $SF_6$ according to Paschen's law, the coexisting stage of $SF_6$ gas with liquid in considerable deviation at lower temperature, and the stage of $LSF_6$ and remaining air. The result shows that the ability of the $LSF_6$ insulation is higher than the high-pressurized $SF_6$. Moreover, it reveals that the breakdown characteristics of $LSF_6$ are produced by bubble-formed $LSF_6$ evaporation and bubbles caused by high electric emission and the corona. In addition, the property of dielectric breakdown of $LSF_6$ is determined by electrode form, electrode arrangement, bubble formation and movement, arc extinguishing capacity of the media, difficulty in corona formation, and the distance between electrodes. The bubble formation and flow separation phenomena were identified for $LSF_6$. It provides fundamental data not only for $SF_6$ gas useless equipment but also for electric insulation design of high-temperature superconductor and cryogenic equipment machinery, which will be developed in future studies.

• The Journal of the Korea Contents Association
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• v.13 no.10
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• pp.444-451
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• 2013

The purpose of this study was to investigate the changes in temporospatial variables in healthy elderly and healthy adults during usual walking, narrow base walking and centerline-guided walking. Twenty healthy elderly and nineteen healthy adults were participated in this study. In each conditions, the subjects were walked on a 6m walkway at comfortable self-selected speeds under three conditions : (1) usual walking, (2) walking within a 50% of the distance between the subject's ASIS (3) walking along a centerline. GAITRite system was used for kinematic analysis to assess the temporospatial variables. There were no significant changes in healthy adults(p>.05), but walking speed, cadence, H-H base support, functional ambulation performance were significantly decreased progressively as pathway narrowed in elderly adults(p<.05). The results show that elderly people had more difficulty with walking on narrow pathway for fear of falling. This study provides data for use in basic research into safe walking and preventing falling for elderly.