• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.4
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• pp.66-74
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• 2000

The purpose of this study is to research and analyze the distribution of night illumination level at urban neighborhood parks and to show its characteristics. And this is used basic data ensuring safety and satisfying aesthetic and psychological desires of people who use urban neighborhood parks at night. To research and analyze the distribution of illumination level at urban neighborhood parks at night. To research and analyze the distribution of illumination level at urban neighborhood parks, I selected 8 urban neighborhood parks as the subject of research in this study, set the measuring standard of illumination level, and measured the illumination level by the measuring standard. The results of this study are as follows; 1. Currently, total average illumination level of urban neighborhood parks was lower than the minimum standard of illumination level I KS A 3011-1993. 2. Average illumination level of each place in urban neighborhood parks appeared variously from low level to high level. But this was lower than the minimum standard illumination level in KS A3011-1993 like total average illumination level. 3. The higher was total average illumination level of urban neighborhood parks, the more various was brightness of places. Although users' aesthetic and mental desire or behavioral aspect relate with safety cannot be found by only survey and analyses of illumination level, it is judged that first, illumination level of the standard of the lightness should be analyzed to find user's mental states and behaviors in external space at night. Therefore, it is considered that this study, which analyzed characteristics illumination level as basic data, has a significance. The study continuing for other illuminative environmental factors suitable in the place is required because the brightness of places may not be measured by only illumination level. And the proper illumination level in outdoor places should be showed in considering psychological and behavioral aspects of human as people may have their own sense of brightness.

• Journal of the Ergonomics Society of Korea
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• v.32 no.1
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• pp.37-45
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• 2013

Objective: This study describes the change of operator performance in drastic change of illumination level, and proposes an alternative method to cope with it. Background: The control standard of illumination for nuclear power plants(NPPs) is based on the set of limit criteria for maintaining a specific illumination level. However, there is a possibility to cause human errors according to the psychological and physiological influences to operators in the situation of drastic change of illumination such as SBO(Station Black Out), so a basic study is necessary to review the current approach. Method: We assessed the visual fatigue, subjective work load and task performance according to the three illumination situations(Normal Illumination, Emergency Illumination, and Drastic Change of Illumination). Result: Research finding shows that there are not significant differences in task performance between normal illumination (1,000lx level) and emergency illumination (100lx level), only if beyond the dark adaptation limit. However, subjective work load on mental demand and visual fatigue show a potential challenge to visual performance in drastic change of illumination. Conclusion/Application: Several trials can complement this challenge in NPPs by applying 3-way communication, enhancing readability of procedures, and managing the visual factors affecting the operators' performance through a Visual Environment Management Program including visual health aspects, etc.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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• pp.1926-1931
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• 2012

We investigated a novel fast non-uniform illumination correction method for bi-level images. The proposed method divides a bi-level image into sub-images and roughly estimates block-wise illumination by low pass filtered maximum values of sub-images. After that, we apply bilinear interpolation using the block-wise illumination to estimate non-uniform illumination, and compensate for the effect of non-uniform illumination using the estimated illumination. Since the proposed method is not based on computation intensive iterative optimization, the proposed method can be used effectively for applications that require fast correction of non-uniform illumination. In simulations, the proposed method showed more than 20 times faster speed than existing entropy minimization method. Moreover, in simulations and experiments, the restored images by the proposed method were more close to true images than images restored by conventional method.

• Korean Institute of Interior Design Journal
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• v.13 no.6
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• pp.167-174
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• 2004

The purpose of this study is to examinethe present illumination conditions in office environment and to suggest an efficient illumination plan in office planning process. Illumination conditions in work environment were surveyed in 6 offices to investigate whether the present illumination conditions were appropriate to the work type. The results of this study are as follows: Most of the general Illuminance level in the area of work were all at an adequate level, except one. The average Illuminance level in the all meeting rooms were met for the standard. Illuminance in the all reception area were extremely over the standard, The illuminations of this area were rather designed according to the image of the company than the standard. As for the illumination method in the area of general work, four offices used a general lighting by a direct lighting type, while two offices used a general lighting and a task lighting at the same time. This survey suggested that first, each company should consider illumination plan in the building planning process, second, illumination plan considering the type of places is needed, and third, illumination environment may be differentiated according to the work type. In conclusion, efficient illumination environment should be considered in office building planning process, especially In terms of illumination materials and methods.

• Physical Therapy Rehabilitation Science
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• v.4 no.1
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• pp.32-37
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• 2015

Objective: This study was conducted to test the effects of mobile texting and gaming on gait with obstructions under different illumination levels. Design: Cross-sectional study. Methods: Twelve healthy adults aged 20 to 36 years (mean 23.5 years) were tested under six different conditions. All participants used touchscreen smartphones. Testing conditions included: 1) Walking with an obstruction under a bright illumination level; 2) walking with an obstruction with a low level of illumination; 3) walking with an obstruction while texting under a bright illumination level; 4) walking with an obstruction while texting with a low level of illumination; 5) walking with an obstruction while gaming under a bright illumination level; and 6) walking with an obstruction while gaming with a low level of illumination. All participants were asked to text the Korean national anthem by their own phone and play Temple Run 2 using an iPhone 5. Gait variances were measured over a distance of 3 m, and the mean value after three trials was used. A gait analyzer was used to measure the data. Results: Compared to normal gait with obstruction, gait speed, step length, stride length, step time, stride time, cadence while texting and gaming showed significant differences (p<0.05). Differences between the illumination levels included gait speed, step length, stride length, and step time (p<0.05) with no significant differences in stride time and cadence. Conclusions: Dual-tasking using a smartphone under low levels of illumination lowers the quality of gait with obstructions.

• Korean Journal of Applied Biomechanics
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• v.25 no.4
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• pp.413-421
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• 2015

Objective : The purpose of this study was to investigate biomechanical changes of the lower limb including dynamic stability with changes in illumination (300Lx, 150Lx, and 5Lx) and slope (level and $15^{\circ}$ downhill) as risk factors for elderly falls. Method : Fifteen elderly females were selected for this study. Seven infrared cameras (Proreflex MCU 240: Qualisys, Sweden) and an instrumented treadmill (Bertec, USA) surrounded by illumination regulators and lights to change the levels of illumination were used to collect the data. A One-Way ANOVA with repeated measures using SPSS 12.0 was used to analyze statistical differences by the changes in illumination and slope. Statistical significance was set at ${\alpha}=.05$. Results : No differences in the joint movement of the lower limbs were found with changes in illumination (p>.05). The maximum plantar flexion movement of the ankle joints appeared to be greater at 5Lx compared to 300Lx during slope gait (p<.05). Additionally, maximum extension movement of the hip joints appeared to be greater at 5Lx and 150Lx compared to 300Lx during slope gait (p<.05). The maximum COM-COP angular velocity (direction to medial side of the body) of dynamic stability appeared to be smaller at 150Lx and 300Lx compared to 5Lx during level gait (p<.05). The minimum COM-COP angular velocity (direction to lateral side to the body) of dynamic stability appeared smaller at 150Lx compared to 5Lx during level gait (p<.05). Conclusion : In conclusion, elderly people use a stabilization strategy that reduces walk speed and dynamic stability as darkness increases. Therefore, the changes in illumination during gait induce the changes in gait mechanics which may increase the levels of biomechanical risk in elderly falls.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.2
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• pp.19-26
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• 2009

This paper studies on the recognition rate change with respect to illumination variance and the confidence level of PCA(Principal Component Analysis) based face recognition by measuring the cumulative match score of CMC(Cumulative Match Characteristic). We studied on the confidence level of the algorithm under illumination changes and selection of training images not only by testing multiple training images per person with illumination variance and single training image and but also by changing the illumination conditions of testing images. The experiment shows that the recognition rate drops for multiple training image case compared to single training image case. We, however, confirmed the confidence level of the algorithm under illumination variance by the fact that the training image which corresponds to the identity of testing image belongs to upper similarity lists regardless of illumination changes and the number of training images.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1822-1829
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• 2015

In this study, artificial neural networks were used to determine the intensity of brightness in interior spaces. The illumination elements to illuminate indoor spaces were considered, not individually, but as a system. So, during the planned maintenance periods of an illumination system, after its design and installation, simple brightness level measurements must be taken. For a three-dimensional evaluation of the brightness level in indoor spaces in a speedy and accurate manner, the obtained brightness level measurement results and artificial neural network model were used. Upon estimation of the most suitable brightness level for indoor spaces by using the artificial neutral network model, the energy demands required by the illumination elements decreased. Consequently, in this study, with estimations of brightness levels, the extent to which the artificial neutral networks become successful was observed and more correct results have been obtained in terms of both economy and usage.

• Journal of the Korean Home Economics Association
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• v.35 no.4
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• pp.149-158
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• 1997

The purpose of this study is to investigate the actual conditions of illumination circumstances in living rooms and the evaluation of residents about those. The respondents of this study were residents of 236 detached houses and 163 apartment houses in Taegu city, The results are as follows: (1) Fluorescent lamps are usded in living rooms by half and plural lighting fixtures are generally used; ceiling light and chandelier. While direct light system is generally used and core type is the most frequent in living rooms. (2) The average used illumination level is 59.7 1x while the possession illumination level is 84.9 1x by investigating of illumination circumstances. (3) Over half of residents are satisfied with illumination circumstances in their own houses. While they wish to improve the lighting fixtures lightness and the kind of light soure in order. And the evaluation of residents are medial level.

• Korean Journal of Applied Biomechanics
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• v.20 no.4
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• pp.381-386
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• 2010

This study examined the changes in the walking pattern during level walking under low illumination conditions. Fourteen male subjects ($22.1{\pm}2.21$ years, $174{\pm}3.74\;cm$, $68.86{\pm}10.81\;kg$) with normal vision and no disabilities were enrolled in this study. All experiments were performed on a level walkway with three conditions: normal walking (preferred & low speed) and walking with low illumination. 3D motion capturing system was used for acquisition and analysis of the walking motion data with a sampling frequency of 120Hz. The walking speed, normalized jerk(NJ) at the center of mass(COM), wrist and heel, knee and elbow joint angle, ratio of the knee joint angle to elbow joint angle and the toe clearance on stance phase were used to compare the differences in walking pattern between the two illumination conditions, The results showed that the walking speed and joint angles decreased in low illumination, whereas the NJ and toe minimum clearance increased. In low illumination, most variables were similar to effects of low speed walking, but toe clearance was different from the effects of low speed. These results can be used as primary data for examining the changes in the level walking pattern of young adults under low illumination. Further study will be needed to compare these results in young adults with those in the elderly.