• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6D
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• pp.663-673
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• 2009

Driver's perceived curve radius is different from actual curve radius at curve sections. This is called visual distortion. It has effect on operation speed according to driver's perception and finally bad effect on safety at curve sections. At present, however, there is no research on quantitatively analysis of visual distortion and no criteria for curve section design considering the visual distortion. Therefore, this study focus on finding degree of visual distortion and suggesting design criteria by visual distortion analysis. The process of this study is as below; First, a calculaiton model of perceived curve radius was developed by survey using computer simulation. In this model, a dependent variable is perceived curve radius and an independent variable is geometric factors. Second, degree of visual distortion was calculated from ratio of perceived curve radius to actual curve radius. Finally, design criteria were suggested through influencing factor analysis of visual distortion at curve sections.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.4D
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• pp.395-402
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• 2010

The seriousness of a traffic accident appears relatively higher on the curve sections compared with the straight sections due to a change in speed caused by a change in the driver's sight. In particular, the visual distortion phenomenon, one of the dangerous factors taking place on the curve sections, appears different according to the road's geometric design. Although it is a genuinely principal design factor which should be necessarily considered in designing a road, the previous researches on establishing the design standards for it have been insufficiently conducted. As a result, the establishment of the road design standards for the curve sections considering the sight distortion phenomenon is desperately required. This research examined the previous researches on the driver's behaviors, the driver's sight characteristics and the perceived curve radius on the curve sections, and developed the theoretical model of perceived curve radius to which a mathematical technique is applied in consideration of the visual distortion phenomenon on the two-lane curve sections in a local area. In addition, after the theoretical visual distortion was calculated on the basis of the theoretical model of perceived curve radius, the range of error on the theoretical recognition radius model formula was verified through comparing it with the previous researches' experiential visual distortion level and analyzing both of them. As a result, it was observed that as the curve radius practically increases in the theoretical recognition curve radius, the range of error tends to go down, which reflects well the characteristics of the curve sections on the road. Based on this research, it is expected that this research will be helpful to eliminate the safety defects when designing the curve sections and contribute to develop the road design standards considering human factors in the future.

• 한국도로학회:학술대회논문집
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• 2009.11a
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• pp.25-32
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• 2009

• Korean Journal of Cognitive Science
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• v.26 no.1
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• pp.27-51
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• 2015

The present study tested the effect of a top-down influence on recalling the colors of Stroop words. Participants remembered the colors of 1, 2, 3 or 6 Stroop words. After 1 second of a memory delay, they were asked to recall the color of a cued Stroop word by selecting out its corresponding color on a color-wheel stimulus. The correct recall was defined when the participants chose a color that was within ${\pm}45^{\circ}$ from the exact location of Stroop word's color on the color-wheel. Otherwise, the recall was defined as incorrect. The analyses of the frequency distribution of the participants' responses in the error trials showed that the probability of choosing the color-name of the target Stroop word was higher than the probability of other five color-names on the color-wheel. Further analyses showed that increasing the number of Stroop words to manipulate memory load did not affect the probability of the Stroop interference. These results indicate that the top-down interference by Stroop manipulation may induce systematic distortion of the stored representation in visual working memory.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.5
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• pp.424-431
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• 2002

This paper proposes a new quantitative image assessment model which is essential to verify the performance of block-based DCT coding. The proposed model considers not only global distortions such as frequency sensitivity and channel masking using HVS based visual model, but also distortions including several local distortions caused by block-based coding.

• Korean Architects
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• s.560
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• pp.82-87
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• 2015

지난 회에서는 형태와 형태이면에 있는 구현의 논리를 모두 다룰 수밖에 없는 파라메트릭 툴의 성격에 대하여 간략하게 이야기 해보았고 이를 반증할수 있는 곡면상의 패널링의 예를 살펴 보았습니다. 삼차원 곡면으로 인해 발생하는 패널들의 시각적 왜곡 및 구축상의 어려움을 해결하고자 왜곡이 발생하는 물리적인 이유를 이해하고 이를 미적분의 개념을 빌어 해결해 보았습니다. 오늘 살펴볼 예도 이와 비슷한 미적분의 개념을 빌리게 되지만 문제의 해결을 위함이 아닌 자연 현상을 시뮬레이션 하고 시뮬레이션의 결과로 얻어진 데이터를 설계에 반영하기 위함이라는데에 차이가 있다고 할 수 있겠습니다. 오늘 살펴볼 내용은 Harvard GSD에서 대학원 설계 수업의 일환으로 제가 진행하였던 파라메트릭 디자인 워크샵의 결과물이며 추후에 이를 실무에 이용하게 됩니다.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.1
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• pp.39-45
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• 2004

This paper proposes a new blind measurement model of blocking artifacts. This model plays an important role in the assessment and enhancement of image quality caused by block-based DCT coding system. The proposed model can measure blocking artifacts without reference to original images and consider the HVS based visual model such as frequency sensitivity and channel masking effect to detect and measure overall blocking artifacts quantitatively. The experimental results show that the proposed model is highly effective in measuring blocking artifacts.

• Journal of IKEEE
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• v.13 no.2
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• pp.224-231
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• 2009

Unsharp masking is a popular image enhancement technique used to sharpen an image appearance in gray images. However, the conventional unsharp making techniques amplify the noise and easily cause overshoot artifacts. Moreover, the unsharp masking tends to introduce color distortion when it is applied to the each color component independently. To solve these problems, we propose a novel unsharp masking technique based on human visual system and vector projection. The proposed algorithm consists of two steps. First, the proposed algorithm controls the level of sharpening by exploiting the characteristics of the human visual system and contrast region. Then the vector projection is applied to remove the color distortion. Experiment results show that our proposed algorithm successfully produces sharpened images that are free of noise and color distortion commonly found in the conventional unsharp masking algorithms.

• 한국사회복지학회:학술대회논문집
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• 2008.04a
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• pp.93-104
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• 2008

사회복지 분야는 정부가 개입해야 하는 대표적인 정책영역이나, 공공성을 강조하면서, 시장기능을 전혀 고려하지 않는 정부개입은 정부실패라는 왜곡을 발생시킨다. 사회복지 서비스는 공공재라기 보다는 가치재로서, 사유재 성격을 가지므로 정부와 시장역할에 대한 균형된 시각이 필요하다. 시장실패와 함께 정부실패라는 경제적 왜곡현상을 동시에 고려하면서, 정부와 시장의 최적역할분담이 이루어져야 한다. 보육정책의 방향은 공공성이 높으므로, 정부가 주도가 되어 모든 국민들에게 똑같은 보육서비스를 공급하는 것이다. 획일적인 보육서비스 질을 정부재원의 확대로서 높이려는 정책방향은 필연적으로 정부실패라는 왜곡을 발생시킨다. 현재 많은 전문가들이 지적하는 민간부문의 보육서비스 질이 낮은 근본원인은 시장규제에 있다. 즉 영리법인의 시장진입을 금지하고, 가격을 규제하고 있기 때문이다. 따라서 보육서비스 질을 높이기 위해서는 보육시장의 정부규제를 철폐해야 한다. 보육시장에 대한 규제 철폐없이 모든 국민들을 대상으로 한 보육재정의 확대는 재정의 낭비를 초래하게 된다. 보육정책의 바람직한 방향은 정부와 시장의 역할분담을 통해서이다. 보육서비스의 외부 불경제 효과가 높은 만큼, 시장에서 충족시키지 못하는 일정소득 이하 계층에 대한 보육서비스는 정부에서 무상으로 제공해야 한다. 그러나 일정소득 수준이상의 계층에게는 다양한 수요가 시장기능에 의해 해결될 수 있도록 해야 한다. 시장실패의 논리와 함께 정부실패라는 왜곡의 심각성을 인식하고, 정부와 시장기능에 대한 최적의 역할분담이 이루어져야 한다.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.61-68
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• 2007

Two experiments examined the visual memory distortion by presenting 170 subjects with wide-angle views of four scenes on monitor screen. Retention interval of 0, 1 and 48 hours tested in reproduction and recognition experiment. The results of reproduction showed that the subjects tend to magnify the foreground and background of scenes compared to the real input (scene) for all retention intervals. The viewers recognized mure wide-angle views for the same scenes at the retention interval of 1 and 48 hours. These results demonstrated boundary extension is not a robust and unidirectional phenomenon but boundary contraction can be occurred with wide-angle views. The results also suggested that boundary contraction is the product of the activation of a memory schema hypothesis: In memory the representation moves toward a prototypical view and prototypical object size.