• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.1
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• pp.67-74
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• 2022

In recent, the number of real-time traffic information sources and providers has increased as increasing smartphone users and intelligent transportation system facilities installed at roadways including vehicle detection system (VDS), dedicated short-ranged communications (DSRC), and global positioning system (GPS) probe vehicle. The accuracy of such traffic information would vary with these heterogeneous information sources or spatiotemporal traffic conditions. Therefore, the purpose of this study is to propose an empirical strategy of heterogeneous information fusion to improve the accuracy of real-time traffic information. To carry out this purpose, travel speed data collection based on the floating car technique was conducted on 227 freeway links (or 892.2 km long) and 2,074 national highway links (or 937.0 km long). The average travel speed for 5 probe vehicles on a specific time period and a link was used as a ground truth measure to evaluate the accuracy of real-time heterogeneous traffic information for that time period and that link. From the statistical tests, it was found that the proposed fusion strategy improves the accuracy of real-time traffic information.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.284-298
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• 2022

It is necessary to acquire information on traffic safety facilities installed on the roadways specifically for the operation of autonomous vehicles. The purpose of this study is to prepare a Korean version of an integrated message-set design as a way to provide to autonomous vehicles standardized information on traffic safety facilities. In this study, necessary facilities are classified according to four criteria (no legal basis; not providing information to autonomous vehicles; providing duplicate information; not standardized, and too difficult to generalize) based on information that must be provided to operate autonomous vehicles. The priority of information delivery (gross negligence followed by behavior change) was classified according to the importance of the information to be provided during autonomous driving, and the form was defined for the classification code in the information delivered. Finally, the information location and delivery method of traffic facilities for compliance with SAE J2735 were identified. This study is meaningful in that it provides a plan for roadway operations by suggesting a method for providing information to autonomously driven vehicles.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.3
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• pp.38-50
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• 2023

Recent advances in artificial intelligence (AI) technology have enabled the integration of AI technology into image sensors, such as Closed-Circuit Television (CCTV), to detect specific traffic incidents. However, most incident detection methods have been carried out using fixed equipment. Therefore, there have been limitations to incident detection for all roadways. Nevertheless, the development of mobile image collection and analysis technology, such as image sensors and edge-computing, is spreading. The purpose of this study is to estimate the reducing effect of the incident detection time according to the introduction level of mobile image collection and analysis equipment (or connected vehicles). To carry out this purpose, we utilized data on the number of incidents collected by the Suwon branch of the Gyeongbu expressway in 2021. The analysis results showed that if the market penetration rate (MPR) of connected vehicles is 4% or higher for two-lane expressway and 3% or higher for three-lane expressways, the incident detection time was less than one minute. Furthermore, if the MPR is 0.4% or higher for two-lane expressways and 0.2% or higher for three-lane expressways, the incident detection time decreased compared to the average incident detection time announced by the Korea Expressway Corporation for both two-lane and three-lane expressways.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.5
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• pp.26-37
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• 2016

As activities and convenience of residents in outdoor spaces in apartment houses have been considered important, strategies for making outdoor spaces in apartment houses healing spaces have emerged as a major interest. The purpose of this study is to draw elements for planning healing to create healing spaces in collective housing areas and to present design guidelines. The findings of this study are as follows. Functional elements of a healing environment were classified into safe environment, therapeutic environment, ancillary environment, orientation-reinforcing environment, amenities, and social environment. Outdoor spaces in collective housing areas were divided into collective housing entrance areas, internal and external spread areas, outdoor activity areas, and areas by theme. First, collective housing entrance areas should be planned in such a manner that residents can feel the area is private and easy to recognize. Second, internal and external spread areas should be planned in such a manner that they are easy to access and communicate with neighbors. Third, outdoor activity areas should be divided into an open space, resting space, playing space, and sports space. Open spaces should be planned in such a manner that they can command a fine view and respect the privacy of nearby residents. Resting spaces should be equipped with a shelter that protects users from direct sunlight, rain, and snow as well as include a movable bench. Playing spaces should be built considering development of children's curiosity, adventurous spirit, character, stimulation, and physical health. Playing spaces should be designed in such a manner that roadways and sidewalks can be separated for safe traffic. Sport spaces should be planned in such a manner that they can be associated with a pavilion and trail that provide residents with an opportunity to communicate with each other and rest. Fourth, spaces by theme are classified into sense garden, therapeutic garden, experiential garden, and learning garden. Sense gardens are a small garden based on the five senses. Sense gardens should be designed in such a manner that they can improve users' mental and physical health through programs that stimulate the sense of sight, auditory sense, and olfactory sense. Therapeutic gardens should be designed in such a manner that they can provide a comfortable and relaxing space by minimizing noise. It is advisable for therapeutic gardens to be equipped with a medicinal herb garden, meditation garden, and sense garden. Experiential and learning gardens should be designed in such a manner that they can provide users with a space in which they can enjoy nature and leisure activities. It is advisable for experiential and learning gardens to be equipped with a tea garden, vegetable garden, and camping garden. Healing programs should be designed in such a manner that users can feel relaxed by providing a healing environment, making the most of the natural environment. Further research on evaluating whether the findings of this study are effective in healing in a qualitative and quantitative manner is needed.

• Journal of Korean Society of Transportation
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• v.17 no.1
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• pp.29-39
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• 1999

An earlier study of the effect of rain found that the capacity of freeway systems was reduced, but did not address the effects of rain on the nature of traffic flows. Indeed, the substantial variation due to the intensity of adverse weather conditions is entirely rational so that its effects must be considered in freeway facility design. However, all of the data in Highway Capacity Manual(HCM) have come from ideal conditions. The primary objective of this study is to investigate the effect of rain on urban freeway traffic flows in Seoul. To do so, the relations between three key traffic variables(flow rates, speed, occupancy), their threshold values between congested and uncontested traffic flow regimes, and speed distribution were investigated. The traffic data from Olympic Expressway in Seoul were obtained from Imagine Detection System (Autoscope) with 30 seconds and 1 minute time periods. The slope of the regression line relating flow to occupancy in the uncongested regime decreases when it is raining. In essence, this result indicates that the average service flow rate (it may be interpreted as a capacity of freeway) is reduced as weather conditions deteriorate. The reduction is in the range between 10 and 20%, which agrees with the range proposed by 1994 US HCM. It is noteworthy that the service flow rates of inner lanes are relatively higher than those of other lanes. The average speed is also reduced in rainy day, but the flow-speed relationship and the threshold values of speed and occupancy (these are called critical speed and critical occupancy) are not very sensitive to the weather conditions.