• Journal of Electrical Engineering and information Science
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• v.3 no.2
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• pp.202-210
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• 1998

This paper is concerned with an efficient generation of stereoscopic views for complex virtual environments by exploiting frame coherence in visibility. The basic idea is to keep visible polygons throughout the rendering process. P-buffer, a buffer of image size, holds the id of the visible polygon for each pixel. This contrasts to the frame buffer and the Z-buffer which hold the color information and the depth information, respectively. For the generation of a consecutive image, the position and the orientation of the visible polygons in the current view are updated according to the viewer's movements, and re-rendered on the current image under the assumption that, when the viewer moves slightly, the visibility of polygons remains unchanged. In the case of stereoscopic views, it may not introduce much difficulty when we render the right(left) image using visible polygons on the (right) image only, The less difference in two images is, the easier the matching becomes in perceiving depth. Some psychophysical experiments have been conducted to support this claim. The computational complexity for generating a fight(left) image from the previous left(right) image is bounded by the size of image space, and accordingly. It is somewhat independent of the complexity of the 3-D scene.

• Journal of Information Technology Applications and Management
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• v.25 no.2
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• pp.1-21
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• 2018

This study aims to investigate the usage patterns of users in Social Network Services (SNS) where is an upsurge. Specifically, the paper considers the reason why young people more and more prefer online (or mobile) SNS activities rather than offline face-to-face social relationship. Furthermore, the drivers which affect SNS usages are considered from users' personal characteristics and social influences. User's personal characteristics include their personalities (extraversion and introversion), narcissism, and life satisfaction. Social influences involve subjective norm, visibility, and image. Affected by personal and social factors in SNS, users intend to show positive self-presentation, which refers to a behavior to selectively expose his/her goodness to others. As one of the most influential drivers affecting SNS usage, the positive self-representation has an effect on the level of SNS usage. Thus, this paper suggests the hypothesized research model focusing on positive self-representation in the relationship among personal characteristics, social influence, and user's behavior in SNS. Empirical data analysis with 100 questionnaires suggests that all hypotheses were adopted except for the effect of visibility among social influence factors on positive self-representation.

• Journal of Information Technology Services
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• v.9 no.2
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• pp.73-92
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• 2010

E-government refers to the delivery of government information and services online through the Internet or other digital means. Unlike traditional structures, e-government systems are two-way, and available 24 hours a day, seven days a week. The interactive aspects of e-government allow both citizens and bureaucrats to send and receive information. Criticism about the provision of e-Government services, however, has proposed a more user-oriented approach. The user needs to be placed at the center of the development and the provision of e-Government services. Furthermore, e-government literatures seldom explore acceptance issues among the aged. Attempting to address this gap, we take the approach based on a combination of Technology Acceptance Model and Theory of Planned Behavior, with data gathered via a questionnaire from service users over 50 years and older. The findings indicate that perceived usefulness, ease of use, subjective norms, trust, visibility, facilitating conditions and political efficacy are direct or indirect predictors of citizens‘ intention to use an e-government service. Implications of this study for research and practice are presented.

• International Journal of Advanced Culture Technology
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• v.9 no.4
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• pp.424-430
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• 2021

The purpose of this study is to analyse the characteristics and spreading laws of parameters such as fire smoke, concentration of CO, visibility, and temperature at fire scene in high-rise residential buildings under the different conditions of fire doors and automatic fire extinguishing systems. Using Pyrosim to simulate diverse fire scenes in a high-rise apartment with corridors, to analyze the changes in those parameters. The results show that when a fire occurs, closing the fire-fighting corridor will increase the smoke temperature and concentration of CO in the stairwell, and reduce the height and visibility of the smoke layer; the automatic fire extinguishing system effectively suppresses the increase in the temperature of the fire smoke and the sedimentation of the smoke layer. Reasonable setting and operation of the automatic fire extinguishing system could effectively inhibit the spread of fire. Although closing fire corridor can slow down the direct upward spread of smoke through the corridor, it will force the fire smoke into the stairwell, which will seriously affect evacuation through the stairs. Therefore, in order to reduce risks, it is forbidden to close the fire doors of the firefighting corridor and stacking combustible materials in the corridor, Also, intensifying inspections and ensuring the normal operation of the automatic fire extinguishing system are indispensable. Based on the research results, the significance of installing fire-fighting facilities in the construction of high-rise apartments was discussed and proved.

• Korean Journal of Construction Engineering and Management
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• v.24 no.5
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• pp.73-82
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• 2023

Optimization of Construction Site Layout Planning (CSLP) heavily relies on workers' travel paths. However, traditional path generation approaches predominantly focus on the shortest path, often neglecting critical variables such as individual wayfinding tendencies, the spatial arrangement of site objects, and potential hazards. These oversights can lead to compromised path simulations, resulting in less reliable site layout plans. While Deep Reinforcement Learning (DRL) has been proposed as a potential alternative to address these issues, it has shown limitations. Despite presenting more realistic travel paths by considering these variables, DRL often struggles with efficiency in complex environments, leading to extended learning times and potential failures. To overcome these challenges, this study introduces a refined model that enhances spatial navigation capabilities and learning performance by integrating workers' visibility into the reward functions. The proposed model demonstrated a 12.47% increase in the pathfinding success rate and notable improvements in the other two performance measures compared to the existing DRL framework. The adoption of this model could greatly enhance the reliability of the results, ultimately improving site operational efficiency and safety management such as by reducing site congestion and accidents. Future research could expand this study by simulating travel paths in dynamic, multi-agent environments that represent different stages of construction.

• Korean Journal of Optics and Photonics
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• v.26 no.2
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• pp.73-82
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• 2015

This work demonstrates the indoor SI-traceable calibration of a transmissometer with a 75-m baseline for the measurement of visibility in MOR (Meteorological Optical Range). The calibration is performed using a set of neutral density (ND) filters (OD 0.1-2.5) and a set of high-transmission quartz glass plates (a bare quartz glass plate and antireflective-coated quartz glass plates), the collection consisting of 20 artifacts in total. The luminous transmittance values of the reference artifacts had been calibrated traceable to the KRISS spectral transmittance scale, which ranges from 0.2 % to 99.5 %. The transmissometer to be calibrated typically consists of a loosely collimated light source based on a white LED (CCT ~5000 K) and a luminous intensity detector with a CIE 1924 V(${\lambda}$) spectral response. As a result of calibration, we obtained the MOR error and its uncertainty for the transmissometer in 20 m - 40 km of MOR. Based on the results, we investigated the applicability of the calibration method and the conformity of the transmissometer to the ICAO's (International Civil Aviation Organization) accuracy requirement for meteorological visibility measurement. We expect that this work will establish the standard procedure for the SI-traceable calibration of a transmissometer.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.04a
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• pp.335-336
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• 2008

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.168-169
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• 1999

시정 모델에 대한 연구로는 국외의 경우 미국 EPA(Environmental Protection Agency)에서의 연구사업으로서 이루어진 바가 대부분이나 우리나라의 경우에는 모델을 적용하여 시정을 연구한 바가 매우 드물다. 이에 본 연구에서는 우리나라의 시정분포의 특성을 살펴보기 위해 급격한 풍향 변화나 오염물질이 장거리로 수송됨에 따라 수 시간씩 소요되는 것에 따른 오염물질의 화학적 변형과 건ㆍ습성 침적을 고려할 수 있는 MESOPUFF II 모델(EPA, 1990)을 이용하였으며, 모델에 의해 계산되어진 황산염과 질산염 농도의 시정 환산을 통해 우리나라의 시정분포를 모의하였다.(중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.65-66
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• 1999

도시지역의 시정변화는 일정한 경향성을 지니는 일부 오염물질들의 배출에 의해 지배적인 영향을 받는 것으로 보고되고 있다. Sulfate, nitrate는 대기중의 상대습도와 밀접한 관계를 지니고 있어서, 일일주기로 증감하는 수증기와의 반응에 의하여 입자의 크기가 성장ㆍ감소하여 대상물체의 이미지 형성광(image forming light)을 산란시킴으로써 관측자의 시야 경로부터 빛을 이탈시키는 현상을 나타낸다.(중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.369-370
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• 2000

동북아시아에서 화석연료의 연소로부터 배출되는 인위적 대기오염물질의 증가는 심각한 문제로 대두되고 있다. 우리 나라의 경우는 도시화, 인구 밀집과 자동차의 증가로 인한 대기오염물질 배출은 대도시에서 공기질 저하를 야기하고 있다. 특히, 서울 지역은 가시도(Visibility), 오존 등의 심각한 공기오염문제를 경험하고 있다. 이러한 대기오염은 국지적 기상변화에 따라 발생하는 도시형 스모그나 안개과 밀접한 관계가 있는 것으로 추정되며, 발생시 에어로졸의 특성변화가 예상되고 있으나, 스모그나 안개 발생시 에어로졸의 특성이나 고도 분포에 대한 연구는 미흡한 실정에 있다. (중략)