• Title/Summary/Keyword: Visibility function

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Study of Methodology for Estimating PM10 Concentration of Asian Dust Using Visibility Data (시정자료를 이용한 황사의 미세먼지 농도추정 방법 연구)

  • Lee, Hyo-Jung;Lee, Eun-Hee;Lee, Sang-Sam;Kim, Seungbum
    • Atmosphere
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    • v.22 no.1
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    • pp.13-28
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    • 2012
  • The $PM_{10}$ concentration data is useful for indentifying intensity and a transport way of Asian dust. However, it is difficult to identify them properly due to the limited spatial resolution and coverage. Therefore, a methodology to estimate $PM_{10}$ concentration using visibility data obtained from synoptic observation was developed. To derive the converting function, correlation between visibility and $PM_{10}$ concentration is investigated using visibility and $PM_{10}$ concentration data observed at 20 stations in Korea from 2005 to 2009. To minimize bias due to atmospheric moisture, data with higher relative humidity over a critical value were eliminated while deriving $PM_{10}$-visibility relationship. As a result, an exponentially decreasing function of visibility is obtained under the condition that relative humidity is less than 82%. Verification of the visibility converting function to $PM_{10}$ concentration was carried out for the dust cases in 2010. It was found that spatial distributions of $PM_{10}$ calculated by visibility are in good agreement with the observed $PM_{10}$ distribution, especially for the strong dust cases in 2010. And correlation between the derived and observed $PM_{10}$ concentration was 0.63. We applied the function to obtain distributions of $PM_{10}$ concentration over North Korea, in which concentration data are not available, and compared them with satellite derived dust index, IODI distributions for dust cases in 2010. It is shown that the visibility function estimates quite similar patterns of dust concentration with IODI image, which suggests that it can contribute for prediction by indentifying transport route of Asian dust.

Non-natural Image Steganography Based on Noise Visibility Function(NVF) (Noise Visibility Function(NVF)를 이용한 비자연 영상에서의 스테가노그래피)

  • 홍지희;권오진
    • Proceedings of the IEEK Conference
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    • 2003.07e
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    • pp.1807-1810
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    • 2003
  • Steganography based on Just Noticeable Difference(JND) has been used for natural images. However, it has been recognized to have defects for the non-natural images such as scanned text images, cartoons, etc. In this paper, an alternative method is proposed to improve this problem. A new scheme is designed specially for the non-natural images. Instead of JND, Noise Visibility Function(NVF) is used. NVF value and edge strength value of each pixel ate combined to decide the embedding data capacity and the visibility of data embedded images have been improved specially for the non-natural images.

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An Empirical Study on the Function and Effect of Urban Openspace - Focusing on Urban Roadside Trees - (도시녹지의 기능 및 효과에 대한 실증적 연구 - 도시 가로수를 중심으로 -)

  • 성현찬;민수현
    • Journal of the Korean Institute of Landscape Architecture
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    • v.31 no.2
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    • pp.48-57
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    • 2003
  • The objective of this study is to review and verify whether the functions and effect of roadside trees generally hewn in theory are actually realized in urban roads and how well they are performed if the function and effect are realized. The study was conducted with a focus on 3 functions and effects including roadside tree's urban landscape improvement function (green area visibility ratio), effect of introducing green area within a city, and urban green network building function. The major study results are as follows: First, the average green area visibility ratio of 41 study areas is currently about 25.90%. The green area visibility ratio of commercial area within downtown was lowest among 5 road types. It showed that it is possible to raise the average green area visibility ratio up to 32.49% through roadside tree management and additional plantation. Second, in a section between Paldal Mountain and Suwon City Hall where there is no forest fragments and parks at all, a green area of 4,826 roadside trees represented 2.4% of total area and served as the only linear green area. Third, an analysis of 15 cities in Kyonggi province showed that urban forests are concentrated in outskirts. The suey showed that because forest fragments and parks exist in a form of points in urban areas, roadside trees are the only green areas that link each other and build a network.

Visibility of Transportation in Global Logistics Environment (Global Logistics환경에서의 Visibility 확보방안)

  • Lee, Sang-Min;Jeong, Jae-Hun;Hwang, Jong-Ha
    • 한국IT서비스학회:학술대회논문집
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    • 2003.05a
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    • pp.222-229
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    • 2003
  • In the process of global transportation, many value chains which have different business process, system and technology level respectively are connected to each other. To obtain end-to-end visibility of transportation, these kind of discrepancy has to be solved appropriately. In this paper, the realization of global visibility is discussed in three point of view such as 'Data Sourcing', 'System integration' and 'System Operation'. First, the data sources of global visibility are described especially from the point of enterprise applications view, and then system integration is presented using various current e-commerce technologies for example XML, EDI and so on. Finally, flexible operation of visibility function is suggested which satisfies different goals of each value chain.

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A Study on Quantitative Analysis Method of Museum Architecture Arrangement - Focused on Space Syntax and Visibility Graph Analysis - (뮤지엄건축 공간배치의 정량적 분석방법에 관한 연구 -공간구문론(Space Syntax)과 가시장분석(Visibility Graph Analysis)을 중심으로 -)

  • Park, Chong-Ku;Lee, Sung-Hoon
    • Korean Institute of Interior Design Journal
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    • v.18 no.4
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    • pp.97-104
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    • 2009
  • This thesis analyzed arrangement and mixture method of function elements, which are getting more important in museum planning. It used quantitative method, Space Syntax and Visibility Graph Analysis tool to analyze five case museums. Through this analysis, advantages and disadvantages of two methods were derived and case museums' arrangement and mixture attributes were grasped. Results of the analysis were derived differently by two kinds of plan form which were room to room type and open type. Open typed museum recorded similar graphs of Integration, Visual Integration and Visual Connectivity. Since whole space structures were relatively simple and structure of exhibition halls were opened, the results of Space Syntax and Visibility Graph Analysis had similar graphs. Room to room typed museum showed differences in Integration, Visual Integration and Visual Connectivity. In the result, the most accessible space was lobby and Mediation Space became the center of visibility. Also, the exhibition hall, where the opening of room to room typed exhibition hall was penetrated visually, became a center of visibility. Lobby space, which was close to entrance, had the highest Visibility Connectivity. As Space Syntax could analyze the museum as whole space structure, Space Syntax showed strength in room to room typed museum analysis compared to open typed museum analysis which has relatively simple structure. Visibility Graph Analysis could expect the flow of exhibit distance including visibility analysis unlike the flow of exhibit distance with space arrangement. The exhibition hall, which secures the sight to penetration of an opening, couldn't be analyzed in existing Space Syntax. However, it became the biggest advantages in Visibility Graph Analysis of room to room typed museum. Visibility Graph Analysis derived detailed results in exhibit arrangement so it will be the useful method not only for architecture but also for planning of exhibit arrangement in open typed museum. Through this study, various possibilities on Quantitative Analysis Method of Museum Architecture could be verified. However, the analysis still has limitation of second dimension. Therefore, diverse and liberal following study will be expected to accomplish.

Measurement and Prediction of the Visibility Range by the Variations of the Character Sizes and Illuminance (글자 크기와 조도의 변화에 의한 가시거리 측정과 예상)

  • Kim, Tae-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.12
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    • pp.8222-8227
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    • 2015
  • The visibility range is defined from where one can see, which can be changed by the character sizes and illuminances and so on, which of one-hundred and twelve students are measured for three illuminances and three character sizes in this paper. In determining the character sizes and illuminances, the visibility range can be an important data. Functions are proposed whose independent variable is illuminance and whose dependent variable is visibility range in order to predict the visibility range of unmeasured illuminances. The fractional functions are used for three character sizes because the visibility range is invariant according to illuminance. There are three parameters to be determined - k, m, n, which are selected based on the measured visibility ranges. Because the visibility ranges of three character sizes are measured, three k's can be calculated. In this paper the case of minimum variance of three k's is selected, and three parameters - k,m,n- of that case is selected. The three functions according to three character sizes are proposed. The small differences between the measured data and the postulated functions verifies the accuracy of the functions.

An Analysis of Driver Perception of Nighttime Visibility Using Fuzzy Set Theory (퍼지집합이론을 이용한 야간 도로 시인성 평가)

  • LEE, Dong Min;Youn, Chun Joo;KIM, Young Beom
    • International Journal of Highway Engineering
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    • v.17 no.5
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    • pp.57-66
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    • 2015
  • PURPOSES: Nighttime driving is very different from daytime driving because drivers must obtain nighttime sight-distances based on road lights and headlights. Unfortunately, nighttime driving conditions in Korea are far from ideal due to poor lighting and an insufficient number of road lights and inadequate operation and maintenance of delineators. This study is conducted to develop new standards for nighttime road visibility based on experiments of driver perception for nighttime visibility conditions. METHODS : In the study, perception level and satisfaction of nighttime visibility were investigated. A total of 60 drivers participated, including 34 older drivers and 31 young drivers. To evaluate driver perceptions of nighttime road visibility, fuzzy set theory was used because the conventional analysis methods for driver perception are limited in effectiveness for considering the characteristics of perception which are subjective and vague, and are generally expressed in terms of linguistic terminologies rather than numerical parameters. RESULTS : This study found that levels of nighttime visibility, as perceived by drivers, are remarkably similar to their satisfactions in different nighttime driving conditions with a log-function relationship. Older drivers evaluated unambiguously degree of nighttime visibility but evaluations by young drivers regarding it were unclear. CONCLUSIONS : A minimum value of brightness on roads was established as YUX 30, based on final analyzed results. In other words, road lights should be installed and operated to obtain more than YUX 30 brightness for the safety and comfort of nighttime driving.

A Fuzzy Neural-Network Algorithm for Noisiness Recognition of Road Images (도로영상의 잡음도 식별을 위한 퍼지신경망 알고리즘)

  • 이준웅
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.5
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    • pp.147-159
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    • 2002
  • This paper proposes a method to recognize the noisiness of road images connected with the extraction of lane-related information in order to prevent the usage of erroneous information. The proposed method uses a fuzzy neural network(FNN) with the back-Propagation loaming algorithm. The U decides road images good or bad with respect to visibility of lane marks on road images. Most input parameters to the FNN are extracted from an edge distribution function(EDF), a function of edge histogram constructed by edge phase and norm. The shape of the EDF is deeply correlated to the visibility of lane marks of road image. Experimental results obtained by simulations with real images taken by various lighting and weather conditions show that the proposed method was quite successful, providing decision-making of noisiness with about 99%.

A Proposal for Workers to Mandatorily Wear High-visibility Safety Clothing in Korea through the Analysis of the Current Status and Evaluation of Its Visibility (국내 고시인성 안전의복의 착용 현황 분석 및 시인성 평가를 통한 착용 의무화 제안)

  • Kang, Inhyeng;Choe, Byongho;Oh, Cheol;Youk, Ji Ho
    • 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.

A Study on Deconstructured Space and Visibility in Clothes - Regarding Hussein Chalayan′s Design- (의복에서의 탈구조적 공간과 가시성에 대한 연구 -후세인 칼라얀의 디자인을 중심으로-)

  • 김혜영
    • Journal of the Korean Society of Costume
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    • v.50 no.4
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    • pp.5-20
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    • 2000
  • Through his geometric design, the Cyprus born fashion designer Hussein Chalayan raises intriguing questions about the very fact of wearing clothes. By purposefully displacing the function of each part of the clothing, such as neck line, hem line, seam, sleeve, etc., Chalayan transforms the meaning of the body that wears clothes. of the human subject as a sovereign possessor of the clothing and the visibility related to fashion. This transformation is achieved by distorting the spaces of his clothing in an unorthodox way. This thesis argues that the significance of such a practice can not be properly understood without relation to the current debate on deconstructionism under way in humanities. Instead of immediately negating the modern frame of Ideas and practices, deconstructionism asks what the assumptions for the modern regime of truth is. In this process, things that lead human beings to sovereign master of knowledge and truth such as reason, subject, body and vision are questioned. In the same context, Chalayan's design not only forces us to rethink the very function of dividing inside and outside by the clothing but also the meaning of boundary operating in numerous sites of modern life. As the human subject is not something pre-given but constructed according to the cultural representation, to which the clothing belongs, fashion can be evaluated to be an active ingredient of constructing the subject. Therefore, Hussein Chalayan's design is at the cross road between the modern and the postmodern regime of fashion.

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