• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.6
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• pp.600-606
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• 2016

Seafarers are often placed in circumstances that require emergency evacuations due to various causes, including ship collisions, sinking, stranding, and fires. Achieving shorter evacuation time is an important factor in increasing the survival rate during these circumstances, but the narrow and complicated structure of ships is an obstacle when it comes to executing a quick evacuation. Also, unpredictable restrictions may be imposed by bad sea or weather. In this study, various experiments were conducted with sailors currently on board ships in order to examine factors that increase evacuation time. The data was then and analyzed. Evacuation time was measured by dividing crews into groups: sailors that were given an explanation of the ship's structure and those that were not. Furthermore, the visibility range was divided into 0 m, 3 m, and 5 m. The results indicated that, having an explanation of the ship structure did not have much of an effect on evacuation time but visibility conditions led to an increase in evacuation time with a maximum of 2.5 to 2.6 times longer when the visible distance was 5 m, 0 m and 3 m. Therefore, ensuring a visible distance of over 5 m was determined to be the most important factor for reducing evacuation time. In the future, effort should be made to ensure a greater visible distance to improve the survival rate of seafarers and passengers on board ships that encounter incidents.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.9-17
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• 2009

Discomfort Glare from the artificial light sources is an important issue in assessment of lighting quality for healthy buildings. Glare, as a factor of the characteristics of brightness, which has been defined as the sensation produced by contrast and luminance within an entire field view, unfavorably influences the occupants who performs visual tasks. It may cause annoyance and discomfort by interruption of visibility. In the whole visual field, glare can be determined by effects of the position, the luminance and the size of the light source and brightness of the surroundings. Therefore, experimental equipment is required to maintain a constant visual lighting environment. Recent studies have been developed and used the instrument for glare sensation evaluation but the instruments showed some difficulties to verify the correlation of glare indicators. The instrument have been developed with reference to former studies. It is called the Glare Tester. This is consist of 2[m]-diameter vertical dome screen painted with white flat paint, and light sources installed inside the screen. These light sources can provide various range of brightness at any inner surface of the screen. 2 Glare light sources can provide the value of luminance within the range of $0{\sim}150,000[cd/m^2]$. Moreover, 12 light sources are used for background luminance and it can perform the value of luminance within the range of $0{\sim}350[cd/m^2]$. Several experiments have been conducted using this Glare Tester to evaluate the range of the visibility, the values of BCD and the glare sensation in lower and upper visual field.

• Archives of Plastic Surgery
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• v.45 no.2
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• pp.158-164
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• 2018

Background During breast augmentation, the transaxillary approach provides the advantage of allowing the mammary prosthesis to be placed through incisions that are remote from the breast itself, thereby reducing the visibility of postoperative scars. For patients experiencing capsular contracture who do not want additional scars, the previous transaxillary scar can be used for site change and implant exchange. Methods This study analyzed 17 patients (34 breasts) with submuscular breast implants with grade III-IV capsular contracture who received treatment from 2010 to 2015. The mean age of the patients was 29 years (range, 20-38 years). The inclusion criterion was a pinch test of more than 3 cm at the upper pole of the breast. Previous axillary scars were used to expose the pectoralis fascia, and submuscular breast implants were removed carefully. The dissection underneath the pectoralis fascia was performed with endoscopic assistance, using electrocautery under direct visualization. Results The mean follow-up period was 14 months (range, 6-24 months). The entire dissection plane was changed from the submuscular plane to the subfascial plane. Round textured gel implants were used, with a mean implant size of 220 mL (range, 160-300 mL). Two patients developed grade II capsular contracture. There were no cases of malposition or asymmetry. Three patients complained of minor implant palpability. None of the patients required additional surgery. Conclusions Endoscopic subfascial conversion may be an effective technique for treating capsular contracture and avoiding scarring of the breast in selected patients.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.5
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• pp.519-524
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• 2009

This paper describes a new sensor system for 3D environment perception using stereo structured infrared light sources and a camera. Environment and obstacle sensing is the key issue for mobile robot localization and navigation. Laser scanners and infrared scanners cover $180^{\circ}$ and are accurate but too expensive. Those sensors use rotating light beams so that the range measurements are constrained on a plane. 3D measurements are much more useful in many ways for obstacle detection, map building and localization. Stereo vision is very common way of getting the depth information of 3D environment. However, it requires that the correspondence should be clearly identified and it also heavily depends on the light condition of the environment. Instead of using stereo camera, monocular camera and two projected infrared light sources are used in order to reduce the effects of the ambient light while getting 3D depth map. Modeling of the projected light pattern enabled precise estimation of the range. Two successive captures of the image with left and right infrared light projection provide several benefits, which include wider area of depth measurement, higher spatial resolution and the visibility perception.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.2
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• pp.257-263
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• 2013

In case of image observation equipments, CCTV for short distance visual field is usually installed and operated mostly as the means of crime-prevention. However, the extensive demand for monitoring problems in case of the increase in intelligent crimes and disasters has led to the necessity of the development of long-distance observation equipments embedded with Night View functions. In case of the Night View equipments, the relevant market is set up to be focused mostly on Thermal Observation Device(hereinafter, TOD), but some shortcomings such as the limitation of image visibility and excessive maintenance cost, etc. have actually caused the necessity of new long distance Night View equipment. Moreover there might follow lots of difficulties in long-distance visualization in the event that irregular reflection is generated by minute particles in the atmosphere such as fog, smog, and dust, etc. These factors are motivate the work presented in this study. Our study is aimed at the realization of Pulsed Laser Illuminator and newly proposed Range-Gated image acquisition technology. And also the implementation of Tracker for continuous trace of the objects of interest from the obtained sequence images.

• Journal of Korea Multimedia Society
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• v.17 no.2
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• pp.143-151
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• 2014

In images degraded by bad weather, edges representing object boundaries become weak and faint. In this paper we present an image enhancement method, which increases image visibility by making edges as clear as possible. First, we choose edge candidate regions by finding local maxima and minima in an image intensity field, and then build a histogram using image intensities of pixels located at the two sides of candidate edges. Second, we decompose this histogram into multiple modes, which are determined by local minima in the histogram. Once modes are computed, we find modes connected by edges in the image intensity field and build link chains of connected modes. Finally we choose the longest link chain of modes and make the distances between every connected modes as large as possible. The darkest mode and the brightest mode should be within the image intensity range. This stretch makes edges clear and increases image visibility. Experiments show that the proposed method real-time enhances images degraded by bad weather as good as well known time-consuming methods.

• International Journal of Highway Engineering
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• v.19 no.1
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• pp.91-106
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• 2017

PURPOSES : Because elderly drivers are more prone to becoming confused when approaching an urban intersection and thus may yield prolong judgment and decision times than non-elderly drivers, to increase the comfort and safety of the intersection environment for elderly drivers, this study applied autonomous driving tests at an urban intersection to examine their driving characteristics. METHODS : To obtain a more comprehensive understanding of driving features, this study collected drive data of non-elderly drivers and elderly drivers via an autonomous experiment using OBD2 and an eye-tracker, in addition to performing a literature review on the measured visibility range of elderly drivers at intersections. This literature review was conducted considering the general knowledge of elderly drivers having relatively reduced visibility. Additionally, as they are commonly more vulnerable, this study analyzes characteristics of elderly drivers as compared to those of non-elderly drivers. CONCLUSIONS : The results of this study can be summarized as follows: 1) the peripheral visible distance of elderly drivers is reduced as compared to that of non-elderly drivers; 2) elderly drivers approach and proceed through intersections at slower speeds than non-elderly drivers; and 3) elderly drivers yield increased driving distances when performing a right or left turn as compared to non-elderly drivers as a result of their reduced speed and acceleration and larger turning radii relative to non-elderly drivers.

• Journal of The Korean Astronomical Society
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• v.48 no.5
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• pp.229-236
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• 2015

We report results of investigation of amplitude calibration for very long baseline interferometry (VLBI) observations with Korean VLBI Network (KVN). Amplitude correction factors are estimated based on comparison of KVN observations at 22 GHz correlated by Daejeon hardware correlator and DiFX software correlator in Korea Astronomy and Space Science Institute (KASI) with Very Long Baseline Array (VLBA) observations at 22 GHz by DiFX software correlator in National Radio Astronomy Observatory (NRAO). We used the observations for compact radio sources, 3C 454.3, NRAO 512, OJ 287, BL Lac, 3C 279, 1633+382, and 1510–089, which are almost unresolved for baselines in a range of 350-477 km. Visibility data of the sources obtained with similar baselines at KVN and VLBA are selected, fringe-fitted, calibrated, and compared for their amplitudes. We find that visibility amplitudes of KVN observations should be corrected by factors of 1.10 and 1.35 when correlated by DiFX and Daejeon correlators, respectively. These correction factors are attributed to the combination of two steps of 2-bit quantization in KVN observing systems and characteristics of Daejeon correlator.

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.3
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• pp.631-639
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• 1996

Electrosurgical technique have been used in dentistry as an aid to soft tissue management for nearly 60 years. However, it was not until the late 1960s that the principles of electrosurgery were understood and improved equipment became available. Electrosurgery is a surgical procedure performed on soft tissue utilizing controlled high frequency electricaI(radio-frequency) currents in the range of 1,500,000 to 7,500,000 cyclesper second. The radio-frequency energy used in electrosurgery is able to cut and coagulate tissue because it focuses the energy at the small, active electrode. Advantages of electrosurgery for soft-tissue management during dental procedures include improved hemostasis, ease of tissue modification, improved visibility and so on, but adverse healing responses-including necrosis of soft tissue and sequestration of alveolar bone-have been reported. The present report provides examples of treatment of soft tissue and pulp tissue of primary teeth by electrosurgery. The results are as follows; 1. Electrosurgical techniques can be used for various procedures in pedodontics. 2. Electrosurgical procedures provide improved hemostasis and visibility in the operating field, which enable to remove, reshape, and contour soft tissues easily. 3. In pulpotomy technique, it was difficult to expect the variable pulpal response based on the degree of heat accumulation and the conditions of pulp tissues. Therefore, electrosurgical pulpotomy could not be considered as a method superior to formocresol pulpotomy. 4. A greater degree of dexterity and experiences in manipulation of the electrode is required compared with the conventional scalpel surgery.

• Journal of Conservation Science
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• v.37 no.4
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• pp.312-321
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• 2021

Underwater archaeology relies heavily on photography and video image recording during surveillances and excavations like ordinary archaeological studies on land. All underwater images suffer poor image quality and distortions due to poor visibility, low contrast and blur, caused by differences in refractive indices of water and air, properties of selected lenses and shapes of viewports. In the Yellow Sea (between mainland China and the Korean peninsula), the visibility underwater is far less than 1 m, typically in the range of 30 cm to 50 cm, on even a clear day, due to very high turbidity. For photographing 1 m x 1 m grids underwater, a very wide view angle (180°) fisheye lens with an 8 mm focal length is intentionally used despite unwanted severe barrel-shaped image distortion, even with a dome port camera housing. It is very difficult to map wide underwater archaeological excavation sites by combining severely distorted images. Development of practical compensation methods for distorted underwater images acquired through the fisheye lens is strongly desired. In this study, the source of image distortion in underwater photography is investigated. We have identified the source of image distortion as the mismatching, in optical axis and focal points, between dome port housing and fisheye lens. A practical image distortion compensation method, using customized image processing software, was explored and verified using archived underwater excavation images for effectiveness in underwater archaeological applications. To minimize unusable area due to severe distortion after distortion compensation, practical underwater photography guidelines are suggested.