• Korean Journal of Remote Sensing
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• v.23 no.4
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• pp.311-321
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• 2007

The diffuse attenuation coefficient for down-welling irradiance $K_d({\lambda})$, which is the propagation of down-welling irradiance at wavelength ${\lambda}$ from surface to a depth (z) in the ocean, and underwater visibility are important optical parameters for ocean studies. There have been several studies on $K_d({\lambda})$ and underwater visibility around the world, but only a few studies have focused on these properties in the Korean sea. Therefore, in the present study, we studied $K_d({\lambda})$ and underwater visibility around the coastal area of the Yellow Sea, and developed $K_d({\lambda})$ and underwater visibility algorithms for ocean color satellite sensor. For this research we conducted a field campaign around the Yellow Sea from $19{\sim}22$ September, 2006 and there we obtained a set of ocean optical and environmental data. From these datasets the $K_d({\lambda})$ and underwater visibility algorithms were empirically derived and compared with the existing NASA SeaWiFS $K_d({\lambda})$ algorithm and NRL (Naval Research Laboratory) underwater visibility algorithm. Such comparisons over a turbid area showed small difference in the $K_d({\lambda})$ algorithm and constants of our result for underwater visibility algorithm showed slightly higher values.

• Journal of Environmental Health Sciences
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• v.44 no.1
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• pp.1-14
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• 2018

Objectives: The purpose of this study is to investigate the main cause of visibility impairment by analyzing the contributions of the light extinction coefficient of major air pollution components and the change of the light extinction coefficient by relative humidity. Methods: The characteristics of the light extinction coefficient calculated by the photochemical method using fine particle component data measured in 2015 in the Gwangju area were examined. Results: The extinction efficiency per unit mass of $PM_{2.5}$ particles was $4.5m^2/g$ and that of $PM_{10-2.5}$ particles was $0.6m^2/g$. This difference indicates that most of the visibility impairment in Gwangju was caused by $PM_{2.5}$ particles. When visibility was poor, the contribution of ammonium sulphate and ammonium nitrate was significantly increased. Relative humidity was also a major cause of visibility decay. The influx of air currents in Gwangju was mostly caused by the long distance movement of pollutants emitted from the eastern part of China. Ammonium sulphate and ammonium nitrate, which are hygroscopic secondary contaminants, were the main causative agents of visibility impairment. Conclusions: Ammonium sulphate and ammonium nitrate were the main causative agents of visibility impairment in Gwangju. The influx of air currents in Gwangju was mostly caused by the long distance movement of pollutants emitted from the eastern part of China.

• Journal of Fashion Business
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• v.17 no.3
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• pp.1-14
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• 2013

This study is about the evaluation of the color arrangements of working clothes that are harmonized with working environment and assist in the protection of workers in industrial sites. This study attempted color arrangement design with the intention of giving order to the colors of working environment and working clothes so as to help improve the safety of work and the management aspects including human resource management, efficiency improvement, and the practice of business ethics. The study method consisted of literature research, empirical research, and evaluation research. The literature research performed theoretical examination about colors, industrial safety, and visibility. Three actual outdoor work sites in the machine industry were chosen and pictures were taken at 20-30 m from workers. The background colors of the work environment of each work site and the colors of the working clothes that were actually worn were analyzed through color values measured with a color-difference meter(CR-400). As a result, it was found that between value and chroma which affect visibility, color arrangement based on differences in chroma could be a greater influence than color arrangement based on differences in value. The results of this study could assist the integration of color schemes among working environment colors, people and working clothes by suggesting color arrangements with improved visibility that are applicable to the working clothes of domestic machine manufacturers that are playing a pivotal role in domestic industries and by presenting appropriate guidelines.

• Journal of Urban Science
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• v.9 no.1
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• pp.61-68
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• 2020

Steps are very common features in our living environment. Unfortunately, the occurrence of accidents on steps is thus inevitable. A failed visibility to recognize a step remains the most common attribute in these accidents. In this research, sensory scales of step visibility were created in order to examine the effects of two factors on step visibility in sensory testing methods; observation height from floor and eye condition while viewing a step from the descending direction. Results of sensory tests revealed strong influence of eye condition on step visibility. Influence of visual characteristics of each step was also examined and clarified.

• Journal of Korea Society of Industrial Information Systems
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• v.6 no.1
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• pp.77-81
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• 2001

Good visibility is essential for drivers. Especially it may be critical when drivers are passing through a tunnel. Lighting is one of the major factors that contribute to or detract from visibility in a tunnel. In order to enhance the visibility a new lighting technique has been proposed: counter-beam. This paper proposes a new scheme for tunnel lighting design and analyzes the counter-beam lighting technique by showing the contrast effect of it. Different situations are set and simulated. This study is expected to contribute improving the visibility in tunnels.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.190-192
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• 2008

GNSS(Global navigation Satellite system) is the system which determines the users' position using the navigation satellites. The position determination using GNSS has to be always Possible to appling GNSS to railway system widely. Especially, to apply GNSS to the safety-critical application, such as train control system, the satellite's visibility has to be always secured. This study describes the necessity of visibility analysis and the method. And also the visibility analysis of the stand-alone GNSS and the integration GNSS are performed and the applicability of GNSS for train control application is analysed.

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.165-173
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• 2017

PURPOSES : The current practice in car headlight visibility performance evaluation is based on the luminous intensity and illuminance of headlight. Such practice can be inappropriate from a visibility point of view where visibility indicates abilities to perceive an object ahead on the road. This study aimed at evaluating the appropriateness of current headlight evaluation method. METHODS : This study measured the luminance of object and road surface at unlit roadways. The variables were measured by vehicle type and by headlight lamp type. Based on the measurements, the distance where drivers can perceive an object ahead was calculated and then compared against such distance obtained by conventional visibility performance evaluation. RESULTS : The evaluation method based on illuminance of headlight is not appropriate when viewed from the visibility concept that is based on object-perceivable distance. Further, the results indicated a shorter object-perceiving distance even when road surface luminance is higher, thereby suggesting that illuminance of headlight and luminance of road surface are not the representative indices of nighttime visibility. CONCLUSIONS : Considering that this study utilized limited vehicle types and that road surface (background) luminance can vary depending on the characteristics of the given road surface, it would likely go too far to argue that this study's visibility performance evaluation results can get generalized to other conditions. Regardless, there is little doubt that the current performance evaluation criterion which is based on illuminance, is unreasonable. There should be future endeavors on the current subject which will need to explore study conditions further, under which more experiments should be conducted and effective methodologies developed for evaluating automotive headlight visibility performance. Needs are recognized particularly in the development of headlight visibility performance evaluation methodology which will take into account road surface (background) luminance and luminance contrast from various perspectives as the former indicates the driver's perception of the front road alignment and the latter being indicative of object perception performance.

• Fashion & Textile Research Journal
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• v.24 no.4
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• pp.471-478
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• 2022

In roadside workplaces, more attention should be paid to the safety of workers. The roadside workers underestimate the effect of the brightness of their clothes and judge that drivers will recognize them easily, and the drivers misjudge that the roadside workers are far away and that the vehicle can be stopped in sufficient time. Therefore, customized safety education reflecting this and wearing work clothes with certified visibility functions are required. In Korea, it is not compulsory for roadside workers and vehicle guide attendants to wear work clothes with a visibility function. In this study, the distance ahead perceived by drivers was measured using manikins wearing certified and non-certified reflective safety vests. The perception distance of the non-certified reflective safety vest was 1.4 times longer than that of the certified reflective safety vest, thus confirming the importance of wearing a certified reflective safety vest. To prevent roadside workers from suffering traffic accidents, we propose the enactment of a law that makes it mandatory for them to wear high-visibility safety clothing. Specifically, Article 32 of the Enforcement Regulation of the Road Traffic Act should include high-visibility safety clothing in life protection equipment, and additionally, to prevent secondary accidents, we propose the enactment of a law requiring the installation and wearing of certified reflective safety vests in vehicles.

• The Journal of Sustainable Design and Educational Environment Research
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• v.11 no.1
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• pp.23-31
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• 2012

The number of school crime has grown continuously for last ten years and its intensity also has reached to serious condition. The concept of CPTED(Crime Prevention through Environmental Design) needs to be focused for improving school environment regarding this context. The exterior space of school environment is variously exposed to school crimes committed by colleague students and also intruders. From the perspective of school CPTED, Natural surveillance as one of the practical strategies requires the micro-scale analysis which clarifies local visibility at each different school exterior space. Thus, the purpose of this research is to develop the analysis method clarifying visibility condition at exterior space of school environment, which supports finding the condition of natural surveillance. The programmed analysis algorithm generated quantitative results clarifying Degree for static visibility and Clustering Coefficient for user tracking visibility. The result of this study produced the analysis method feasible to clarify weak natural surveillance conditions at school exterior spaces. Also, it is expected that the developed analysis method will be used to improve the layout of school exterior space from the perspective of CPTED.

• Journal of Korean Society of Transportation
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• v.25 no.3
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• pp.77-85
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• 2007

The number of accidents occurring at railway crossings is less than the accidents on other sections of roads but they cause enormous socio-economic damages. The geometric aspects of the railway crossing have to allow the drivers to recognize the crossings and take precautions against collisions. Therefore, ensuring visibility for the vehicle approaching the railway crossing is necessary for safe operation of the crossing. However, as there is little research related to railway crossing visibility in Korea. validating visibility and maintaining visibility based on the validation is badly needed. This research develops a visibility validation model to support improving visibility and to reduce accidents at railway crossings to improve safety for the crossing users.