• Journal of Korean Society of Transportation
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• v.29 no.4
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• pp.125-138
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• 2011

The highway visibility reduction caused by fog is one of the major elements of traffic accidents. Though the fog warning systems can lead drivers into safe driving by letting them aware dangerous situations in advance, the optical sensors, such as fog sensor, has been extremely costly. Through recent studies, it is delivered that visibility measurements have become obtainable with relatively cheap cameras and their functionality is as similar as a driver' visual sense. Those measurements however require additional signs or ROI, so it is still costly and unable to utilize the conventional images from the existing systems. This study proposes a new method to detect the visibility in real time based on the conventional images from the existing CCTV cameras. The proposed method builds a road model and extracts and applies vehicle movements and visible lines - those highlight easy and quick visibility measurements. The proposed method has advantages of both (1) having possible day and night visibility measurements similar to drivers' visual sense and (2) being easily applied to the existing CCTV system without additional devices. This paper presents field experiments using images acquired from the Central Inland Expressway and discusses future research directions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.2
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• pp.219-230
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• 2023

Cities are continued to be highly advanced and metropolitanized. Lands adjacent to road make entry/exit connection increase along with construction of facilities for various purposes. However, in the absence of specific installation standards of entry and exit connection, inappropriate access location, types of access, and operation methods are deteriorating the level of traffic services at existing roads and intersections. Therefore, in order to minimize the traffic impact from entrances connected to minor arterial roads and colletor roads, first, this study re-established the waiting length in the intersection of upstream and downstream and length required for changing lanes and between entrance/exit and connection, considering the road and traffic environment in contact with the entrance. Second, it is suggested that the operation method depending on the connection type and whether to install left turn lane and acceleration and deceleration lane can be determined quantitatively by relation with the service level of nearby intersection after calculating the threshold amount of business site through negative social cost, which is the difference between the installation cost of the left turn lane and the acceleration and deceleration lane according to the type of access to the entrance and exit.

• Journal of Navigation and Port Research
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• v.42 no.3
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• pp.187-194
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• 2018

Aids to Navigation (AtoN) is a marine traffic safety facility used to facilitate the safe and efficient movement of shipping and enhance the protection of the marine environment by the regulations or guidelines of The International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA). Our country is managing AtoN to provide consistent services for AtoN users, although an average of 141 AtoN accidents occur annually. An AtoN accident forces non-planned work on the managers to resort the function, and causes psychological anxiety for its users, ultimately resulting in economic losses. This study developed the Social Cost evaluation model of AtoN accidents. The model can be used to quantify the manager's economic activities related to the shutdown and recovery, as well as the cost associated with the inconvenience to AtoN users. The Social Cost evaluation model of AtoN accidents is proposed as the sum of the encounter cost, administration cost and risk cost.

• Journal of Korea Port Economic Association
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• v.28 no.4
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• pp.1-37
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• 2012

The purpose of this paper is to estimate the social costs induced by various transport modes such as truck, rail and sea vessel. For this purpose, we introduce the damage function of each transport modes, and estimate social costs for 10 items using Meta Analysis. As a results, this study can find that shipping is the most efficient transport mode because it gives the lowest social costs among them. This study also find that the iso-cost transport distance that gives the equal social costs between the transport modes. Our methodology can be thought somewhat inferior to the Contingent Valuation Methods, however the advantage of this methodology is that we can decomposite the total social costs into item by item and can apply it to other researches.

• Journal of the Korean Geographical Society
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• v.38 no.4
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• pp.478-489
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• 2003

The existing researches related to the fog have focused on mainly the fog itself and its spatial variation. This study defined the hazardous fog as the fog with visibility under 500 m which caused the severe dangerous situation on roads and might cause traffic accident due to insufficient visibility. This study aimed to develop the hazardous fog index which quantified the degree of danger and included frequency of fog, visibility and its duration. We applied the index to 3 years weather station data in Korea and the results showed the distribution of the hazardous fog and their priority in terms of safety management. This was the first study that introduced the fog index in Korea and that quantified the degree of hazardous fog. These application results were useful for identifying the dangerous area due to hazardous fog and contributing to ensure the safety of eventual road users and road authorities.

• Journal of The Geomorphological Association of Korea
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• v.18 no.1
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• pp.15-27
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• 2011

The canals of China·Northern Europe are different from those of Korea in the phases of the times and physical environment as follows. As the coefficient of river regime is high and the slopes of river is high in our country, the sediments are much deposited on the floor and river channels are meandered and the depth of water are low. So we should dredge the river floor and should construct the dams and lock gates. These will cause streams to be late and to be flooded. The rising and falling of groundwater tables may be fatal to the buildings. The ecosystem will be ruined by water pollution and rising of water levels. We are concerned about the economy of the canals, the low velocity of the canals, reduction of the transportation cost, transshipment cost and terminal cost, tourism·leisure-typed waterway and extreme cost of waterway development. It is proper for us to put in good order and control waterway simply by means of annual schedule, not to construct canal.

• Magazine of the Korea Concrete Institute
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• v.8 no.5
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• pp.123-133
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• 1996

Recently, the construction of infrastructures has been booming and accelerating to keep up with rapid economic growth. Construction activities and operation of transportation facilities cause unfavorable effects such as civil petitions associated with vibration-induced damages or nuisances. Accordingly, the objective of this study is to develop vibration-controlled concrete using various vibration-controlled mixtures, and also to recycle obsolete materials in part. As the first step to achieve this research, preliminary mix designs have been carried out to obtain an appropriate mix proportion above 200kg/$\textrm{cm}^2$ in uniaxial compressive strength. Test specimen based on the mix proportion selected have been actuated by the impact hammer to investigate their dynamic characteristics. Vibration-controlled mixtures are foam, latex, rubber powder and plastic resin, which have been determined to reduce a vibration by and large. KS F2437 and travel time method have been used to figure out 1st natural frequency and dynamic elastic moduli. Damping ratios have been computed by adopting the polynomial curvefitting method and the geometric analysis method on the frequency response spectrum curve. of which results have been compared and analyzed hereon.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.2
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• pp.267-281
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• 2012

SCADA system is a computer system that monitors and controls the national infrastructure or industrial process including transportation facilities, water treatment and distribution, electrical power transmission and distribution, and gas pipelines. The SCADA system has been operated in a closed network, but it changes to open network as information and communication technology is developed rapidly. As the way of connecting with outside user extends, the possibility of exploitation of vulnerability of SCADA system gets high. The methodology to protect the possible huge damage caused by malicious user should be developed. In this paper, we proposed anomaly detection based intrusion detection methodology by estimating self-similarity of SCADA system.

• International Journal of Highway Engineering
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• v.13 no.3
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• pp.75-82
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• 2011

There is the uncertain period of the construction in case of the products meeting the quality standard of KS M 6080, the quality is degraded because of the abrasive loss of the paint caused by vehicle tires as the traffic amount increases and of the loss and detachment of the glass beads providing the retroreflective function. The abrupt degradation of visibility causes the high frequency of traffic accidents at night and increases the traffic accident rate. Additional supplementary construction induces the direct material and construction costs. As the more cost induction effect than the direct cost, the traffic jam caused by the additional construction increases the indirect social costs such as time cost and vehicle cost. Hence, the study is concerned with performing the abrasion resistance test based on the EN 1436 standard to check and improve the quality of various road marking materials resulting in improving the durability of road marking materials. However, even though the difference in the durability lifetime of resins(binders) is bibliographically or theoretically clear, there was no difference in the durability lifetime (retroreflectivity aspect) of the road marking paint using these binders. The reason is that the bonding of beads was very insufficient or that the cross density caused by crack or freshness was low. Moreover, the measured wet retroreflectivity was distributed as the Rw3 or higher class in average on the basis of EN 1436 but was very insufficient on the basis of the minimum wet threshold retroreflectivity with 100mcd/($m^2{\cdot}lx$) managed overseas.

• Journal of Korean Society of Transportation
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• v.24 no.7 s.93
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• pp.15-25
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• 2006

This study was to investigate the impact of region-wide travel pattern on local fiscal capacity in the Seoul metropolitan area. The study adopted both factor analysis and regression modeling for it, while using fiscal-and travel-related variables as well as urban characteristics determining travel patterns. We used the former method to compress independent variables of travel and urban characteristics because of strong correlationship between them. Four factors identified by the analysis output were adopted in regression models with some dependent variables representing local fiscal capacity. Their results resulting from both analyses showed that local fiscal inequality within the metropolitan area is driven by region-wide travel Patterns such as total trips. inner trip ratio, and the ratio of trips from and to the Seoul city.