• Journal of Korean Society of Transportation
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• v.22 no.1 s.72
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• pp.83-94
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• 2004

In 1968, United Nation prepared conventions to promote the safety and vitalization of traffic to accomodate increased international business and personal activities. They are convention on rad traffic and convention on road signs and signals. These conventions define the shape, color and the operational guidelines of signs, marking and traffic signals. However, the Korean road traffic law enforces independently the manufactural and operational guidelines of those devices and marking. Due to different regulations described in those two, potential problem might be expected in terms of international traffic in the near future in Korea. This paper presents the academical comparison between these two different road traffic regulations established by the Korean legislature and United Nation. It suggests a list of researches recommended for the nation to be ready to integrate international traffic.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.183-193
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• 2007

Traditionally, a congestion charge based on first-best congestion pricing theory, namely, the theory of marginal cost pricing theory, is equal to the difference between marginal social cost and marginal private cost. It is charged on each link so as to derive a user equilibrium flow pattern to a system optimal one. Based on this theory this paper investigates on the characteristics of first-best congestion pricing of multiple user class on road with variable demand, and presents two methods for analysis of social and spatial equity. For these purposes, we study on the characteristics of first-best congestion pricing derived from system optimal in time and in monetary unit, and analyze equity from this congestion pricing with an example network.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.4
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• pp.25-35
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• 2008

Variable Message Sign(VMS) is one of the subsystem of Intelligent Transportation Systems (ITS), which is useful for providing real-time information on weather, traffic and highway conditions. However, there are various situations such as incidents/accidents, constructions, special events, etc., which would be occurred on segments, it is unable to control traffic with only the VMS. Thus, it is essential to use of PVMS(Portable Variable Message Signs), which can move to the location needed traffic control and provide more active traffic information than VMS. This study developed a legibility distance model for PVMS messages using in-vehicle Differential Global Positioning Data(DGPS). Traffic conditions, drivers' characteristics, weather conditions and characteristics of PVMS message were investigated for establishing the legibility model based on multiple linear regression analysis. The factors such as height of PVMS characters, spot speed, age, gender and day and night were identified as dominants affecting the variation of legibility distances. It is expected that the proposed model would play a significant role in designing PVMS messages for providing more effective real-time traffic information.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1D
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• pp.129-136
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• 2008

Along with the development in cutting-edge digital technology, the street space is also being changed. Mobile telecommunication units and internet give a big change in a human being's lifestyle. And the ubiquitous computing is proceeding with expanding its application range from the indoor space to the street space. As the street furniture is the convenient facility that allows a human being's life in street space to be abundant, it is getting advanced. First of all, in terms of such phenomenon, this study analyzed the cases of a research on application of street space and the actual condition of a change in the number of individuals for the street furniture, through a literature research of ubiquitous. Also, it researched into the realities of using the street furniture of the walking-desired streets at Daehac-ro and Hongdae district, where are two representative places related to digital generation. The next was carried out FGI (Focus Group Interview) with users of the street space in front of Hongik University and managers of the street furniture, and was researched into the use & management behavior, and recognition level on the street furniture. Thus, the key elements were extracted such as interchange of information for cultural activities, automation for interaction variability in function. Finally the core elements for future vision of street furniture in this digital era were extracted in 3I, namely, Information, Intellectualization, and Integration. This is considered to be applied to the establishment of direction in the process of high-tech digitalization in street furniture related to information hereafter.

• Journal of Biosystems Engineering
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• v.28 no.6
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• pp.511-516
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• 2003

Computer vision technology has been utilized as one of the most powerful tools to automate various agricultural operations. Though it has demonstrated successful results in various applications, the current status of technology is still for behind the human's capability typically for the unstructured and variable task environment. In this paper, a man-machine interactive hybrid decision-making system which utilized a concept of tole-operation was proposed to overcome limitations of computer image processing and cognitive capability. Tasks of greenhouse watermelon cultivation such as pruning, watering, pesticide application, and harvest require identification of target object. Identifying water-melons including position data from the field image is very difficult because of the ambiguity among stems, leaves, shades. and fruits, especially when watermelon is covered partly by leaves or stems. Watermelon identification from the cultivation field image transmitted by wireless was selected to realize the proposed concept. The system was designed such that operator(farmer), computer, and machinery share their roles utilizing their maximum merits to accomplish given tasks successfully. And the developed system was composed of the image monitoring and task control module, wireless remote image acquisition and data transmission module, and man-machine interface module. Once task was selected from the task control and monitoring module, the analog signal of the color image of the field was captured and transmitted to the host computer using R.F. module by wireless. Operator communicated with computer through touch screen interface. And then a sequence of algorithms to identify the location and size of the watermelon was performed based on the local image processing. And the system showed practical and feasible way of automation for the volatile bio-production process.

• Korean Journal of Construction Engineering and Management
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• v.16 no.4
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• pp.41-49
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• 2015

The amount of energy consumed in air ventilation systems of public facilities accounts for 40% of their total energy consumption. To reduce their energy consumption, applying variable speed operation controlled by an inverter with a high-efficiency motor is suggested. Since these methods require higher initial investment costs compared to the existing systems, economic evaluation should be conducted from a long-term perspective. While LCCA(Life Cycle Cost Analysis) model is useful to estimate net savings of alternatives that differs with respect to initial costs and operating costs, the environmental burdens are not considered. On the contrary LCA(Life Cycle Assesment) model is suitable to assess environmental impacts associated with the stages of a product's life but it does not consider costs. In this study, the high-efficient motors are introduced into the air ventilation system of a subway station and a comprehensive analysis on the economic and environmental impacts of the proposed method is conducted by using LCCA and LCA model.

• Journal of IKEEE
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• v.19 no.3
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• pp.349-356
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• 2015

Air Defense Command Control and Alert(ADC2A) system is a system that ensures simultaneity and integrity of air defense operations by combining sensors, weapons and Command and Control(C2) systems over a tactical network to protect forces, facilities and strategic points from enemy's air attack. Improving message processing speed is a very important factor for ADC2A, because it uses high frequency bit-processing of the Army standard KVMF message to communicate with internal and external systems. In this paper we proposed improved method of KVMF message processing for ADC2A system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.167-175
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• 2019

Recently, health examination centers have been changing from auxiliary medical facilities to key and independent medical facilities. However, it is not easy to improve medical facilities, including health examination centers, due to the variable characteristics of the relationship between humans and space. Therefore, this study was done to develop a pedestrian-based discrete event simulation analysis program to examine the problems and develop methods for improvement. The program was developed to analyze five evaluation indices and the density of examinees. The problems were derived by analyzing the required time, capacity, and queue size for each examination through simulations. We reduced the examination time and moving distance, increased the capacity, and distributed the queues by adjusting the medical services and relocating the examination rooms. The results were then quantitatively verified by simulations.

• Journal of Korean Society of Transportation
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• v.22 no.5
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• pp.139-149
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• 2004

As the expansion of road capacity has become impractical in many urban areas, congestion pricing has been widely considered as an effective method to reduce urban traffic congestion in recent years. The principal reason is that the congestion pricing may lead the user equilibrium (UE) flow pattern to system optimum (SO) pattern in road network. In the context of network equilibrium, the link tolls according to the marginal cost pricing principle can user an UE flow to a SO pattern. Thus, the pricing method offers an efficient tool for moving toward system optimal traffic conditions on the network. This paper proposes a continuous network design program (CNDP) in network equilibrium condition, in order to find optimal congestion toll for maximizing net economic benefit (NEB). The model could be formulated as a bi-level program with continuous variable(congestion toll) such that the upper level problem is for maximizing the NEB in elastic demand, while the lower level is for describing route choice of road users. The bi-level CNDP is intrinsically nonlinear, non-convex, and hence it might be difficult to solve. So, we suggest a heuristic solution algorithm, which adopt derivative information of link flow with respect to design parameter, or congestion toll. Two example networks are used for test of the model proposed in the paper.

• Journal of Korean Society of Transportation
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• v.25 no.6
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• pp.141-157
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• 2007

This paper evaluates the effects of privatization and deregulation on the firm-specific efficiency and total factor productivity (TFP) growth in the Korean and Japanese railways. Using a stochastic frontier approach and a generalized translog functional form, the paper specifies the equation system consisting of a multiproduct variable cost function and input share equations which is estimated with Zellner's iterative seemingly unrelated regression and the corrected least squares method. The Korean and Japanese railway firms are assumed to produce three outputs (Shinkansen passenger-kilometers, incumbent railway passenger-kilometers, ton-kilometers of freight) using three input factors (labor, fuel, maintenance and rolling stock). A monetary value of the ways and fixed installations held by the railroad firm is also included as a quasi-fixed input. The empirical results indicate that the average estimate of cost inefficiency is 2.57% for the total sample and on the average, JNR and JR Kyushu are found to be worst efficient while the most efficient railway firm in the sample is JR West. Also the cost efficiency levels of seven JRs have been improved after the reform and privatization of JNR. The findings also indicate that TFP growth of the privately-owned JRs are higher than those of the government-owned KNR and JNR. Three-island JRs and JR Freight have slightly higher TFP growth than Honshu JRs as well. Thus, the results suggest that managerial autonomy and increased competition via deregulation have improved efficiency and TFP growth.