• Journal of Korean Society of Transportation
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• v.25 no.4
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• pp.79-87
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• 2007

The interchanges of urban freeways have many problems with traffic operation due to high off-ramp flows and frequent congestion at adjacent intersections. The flow exiting from off-ramps is affected by the operational status and traffic volume conditions of the nearest signalized intersection. As a result, off-ramp flow cannot exit and the queue backs up the freeway mainline when queues from the signalized intersection form up to the junction of the off-ramp and street. The spacing between an off-ramp and an adjacent intersection is likely to determine the traffic conditions at the adjacent intersection. However, the current design guidelines do not consider such a factor. This study is to develop a model calculating the spacing between off-ramps and adjacent intersections considering the signal, traffic, and road conditions. The variables affecting the model in this study are effective green time (g/C), volume-capacity ratio (v/c), the number of lanes, and off-ramp volume. Various scenarios are designed to represent the effects of the variables and the road networks are constructed using VISSIM, which is a common traffic micro-simulation software package. The queue length is derived from VISSIM and this length is considered as the recommended spacing between the off-ramp and the adjacent intersection. Through the simulation analysis, regression models are developed to calculate the queue length reflecting the various conditions such as signals, traffic, and road configurations. The developed model can be used to create road design guidelines to determine the location of off-ramps in the planning stage.

• Journal of Korean Society of Transportation
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• v.35 no.1
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• pp.63-78
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• 2017

The purpose of this study is to determine the optimal aggregation interval to increase the reliability when estimating representative value of individual vehicle travel time collected by DSRC equipment in interrupted traffic flow section in National Highway. For this, we use the bimodal asymmetric distribution data, which is the distribution of the most representative individual vehicle travel time collected in the interrupted traffic flow section, and estimate the MSE(Mean Square Error) according to the variation of the aggregation interval of individual vehicle travel time, and determine the optimal aggregation interval. The estimation equation for the MSE estimation utilizes the maximum estimation error equation of t-distribution that can be used in asymmetric distribution. For the analysis of optimal aggregation interval size, the aggregation interval size of individual vehicle travel time was only 3 minutes or more apart from the aggregation interval size of 1-2 minutes in which the collection of data was normally lost due to the signal stop in the interrupted traffic flow section. The aggregation interval that causes the missing part in the data collection causes another error in the missing data correction process and is excluded. As a result, the optimal aggregation interval for the minimum MSE was 3~5 minutes. Considering both the efficiency of the system operation and the improvement of the reliability of calculation of the travel time, it is effective to operate the basic aggregation interval as 5 minutes as usual and to reduce the aggregation interval to 3 minutes in case of congestion.

• Journal of Korean Society of Transportation
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• v.31 no.2
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• pp.3-10
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• 2013

Two-lane roads that occupy more than a half of rural highways in Korea have operational problems such as traffic congestion problems due to relatively high traffic volume and safety problems due to overtaking risks in two-lane highways. To solve these problems, a 2+1 road pattern that enables to improve traffic safety and operational efficiency of two-lane highways has been applied in Europe. In this study, in-depth applicability of 2+1 roads to Korean rural highways was investigated based on review results of the successful experience of European 2+1 roads. Then, given the Korean two-lane highway conditions, the service traffic volumes for Korean 2+1 roads was estimated. The analysis results showed that 17,000 veh./day might be the maximum traffic volumes for Korean 2+1 roads.

• Journal of Technology Innovation
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• v.19 no.2
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• pp.153-184
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• 2011

This paper investigates what kind of technological partner firms want to cooperate with in terms of partner location. Two geographical factors are considered. One is geographical proximity, given the tradeoff between the effectiveness of knowledge spillovers in proximity and diverse knowledge absorption from geographically distant partners. The other is how many other firms are co-located with potential partners because it is known that clustering regions can create more technological outputs. Analysis on 2008 Korea Innovation Survey data finds that partner proximity is the single most important factor in choosing a cooperation partner. While firms that are located in a region crowded with related industries prefer proximate partners, others that are surrounded by unrelated industries are more likely to cooperate with distant partners. The findings suggest that geographical proximity matters in partner selection because it not only stimulates knowledge spillovers but also reduces costs involving R&D cooperation such as monitoring costs and information costs. Moreover, firms take into consideration both the benefits and risks of clustering regions. If there are so many unrelated firms that they create agglomeration diseconomies such as congestion costs and unintentional knowledge leakages, firms are more likely to try to find their cooperation partners in other regions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.845-853
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• 2017

The main reason for urban traffic problems is the increasing in the use of private cars. In order to solve this problem, strong traffic demand management policies such as the collection of congestion tolls and the crackdown on freight vehicles are emerging. Now, however, it is necessary to seek ways for users to make changes in traffic behavior through direct communication between public agencies and passenger car users. As a technique to make this possible, mobility management, which aims to use rational passenger cars by inducing behavior change through individual consciousness change, has recently been proved to be effective in overseas. Therefore, this study concluded that the introduction of MM, which emphasizes individual voluntary behavior change, is necessary at present. In order to investigate the ways of inducing voluntary changes in traffic behavior of passenger car users, a questionnaire survey was conducted on traffic experts and the priorities of voluntary traffic behavior change measures were calculated using AHP. As a result of the analysis, it was shown that "to actively appeal to change the traffic behavior by using the mass media" was the top priority. The next priority were in order of company education for the change of traffic behavior, education for the school, and small-scale workshops.

• The Korea Journal of Herbology
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• v.26 no.4
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• pp.39-47
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• 2011

Objective: The roots, leaves, flowers, stems and seeds of Cirsium japonicum var. ussuriense are often used in treatment of human diseases such as hemorrhage, blood congestion and inflammation. Focusing our attention on natural and bioavailable sources of antioxidants and anti-inflammation, we undertook to investigate the antioxidant and anti-inflammatory properties of Cirsium japonicum var. ussuriense used as a folk medicine in Korea. Methods: The extracts of the leaves, stems, flowers, seeds and roots from C. japonicum var. ussuriense were prepared by extracting with water or 80% ethanol. Total flavonoids and polyphenols were measured by a colorimetric assay. The free radical scavenging activity of the extract was analyzed by the DPPH (1,1-diphenyl-2-picryl hydrazyl), ABTS (2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and Griess reagent assay. An oxidative product of nitric oxide (NO), was measured in the culture medium by the Griess reaction. The level of prostaglandin $E_2$ ($PGE_2$) was measured by enzyme-linked immunosorbent assay. The expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were measured by Western blot analysis. Results: Total flavonoid and polyphenol amounts of the leaves (CLE) and flowers (CFE) showed higher than those of the seed extract (CSE), stem extract (CSTE) and roots (CRE). CLE and CFE also showed the high antioxidant activities such as DPPH, NO-like and ABTS radical scavenging activity. An antioxidant activities of these water extracts showed higher than those of 80% ethanol extracts. We investigated the anti-inflammatory effects of CLE on lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. CLE significantly suppressed the levels of the inflammatory mediators such as NO and prostaglandin $E_2$ ($PGE_2$) in dose dependant. Furthermore, the levels of iNOS and COX-2 protein expressions were markedly suppressed by the treatment with CLE extract in a dose dependent manner. Conclusions: These results suggest that CLE water extract has a higher anoxidant and anti-inflammatory activity, these properties may contribute to the oxidative and inflammatory related disease care.

• Journal of the Economic Geographical Society of Korea
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• v.6 no.2
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• pp.403-419
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• 2003

Busan Port, Korea, is a region that must take integrated measures against problems such as the excessive handling of cargo volume, the intensification of port congestion, and the construction of a new port to improve port competitive power. In particular, if a great deal of function in the existing area of Busan Port transfers to a new port, then the problems of port redevelopment will occur as shown in the cases of port developed countries explained hereafter. For Korean ports, port redevelopment in a port zone is implemented for improving the port productivity that targets a local area, but the entire and systematic port redevelopment is not accounted for. Focused on this point, the paper is to present the directions for full-scale port redevelopment of the existing zone of Busan Port. The findings are as follows: First, the region of Busan is divided according to a regional classification that is necessary for port redevelopment. Thereby, 4 zones, total 26 regions of redevelopment were selected. Second, overseas case studies were considered for port redevelopment. From these same studies, appropriate types of port development in Korea were extracted and presented. Third, the status and problems of the selected redevelopment regions were analyzed, and types of port redevelopment were assigned. This study was not applied to the strict evaluation technique by quantitative analysis, but the concept and directions for unprecedented port redevelopment were first defined and established. It is significant to select target areas for redevelopment by regional classification and present directions for developing each region by choosing Busan Port as a real case study. This initiation will greatly contribute to the succeeding study.

• The KIPS Transactions:PartB
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• v.11B no.5
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• pp.603-610
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• 2004

The distributed Information Retrieval System centrally controlled by mediator or meta search engine result in congestion of heavy traffic and int he problem of increment of cost for the reason of the design of complicated algorithm for central control and installation of hardware. So to figure out this problem, the way is needed that has independent retrieval functionality and can cooperate each other without dependency. In this paper, we overview a few works involved in distributed information retrieval system, then, implement algorithm and design the frame-work of distributed information retrieval system using sequential transferring method(STM) including multiple information retrieval system separated from central control. For this first of all, we present a web partition policy which devide and manage web logically and we present the sequential query processing way by means of illustration through changing numbered information retrieval system. Then, we also present 3-layered structure of framework and function and module of each layer suitable for information retrieval system. Last of ail, for effective implementation of STM algorithm we analysis module structure and present description of pseudocode of this, and show that the proposed STM algorithm works smoothly by demonstration of sequential query transfer process between servers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.217-225
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• 2011

Currently our country has very serious problems of traffic congestion and urban environment due to increasing automobile ownership. Recently, our concern about environmentally sustainable transportation and green transportation is increasing, so the government is pushing ahead the policy of bicycle using activation. So it is needed to develop a model to analyze the service level of bicycle roads more realistically. In this study, a neuro-fuzzy inference model to analyze the service level of bicycle roads was built selecting the width of bicycle roads, the number of conflicts during cycling and pedestrian volume, which have fuzzy characteristics, as input variables. The predictability of the model was evaluated comparing the surveyed and the estimated. The values of the statistics, $R^2$, MAE and MSE were 0.987, 0.142, 0.032. Therefore, It may be judged that the explainability of the model is very high. The service levels of bicyle roads estimated by the model are 1~3 steps lower than KHCM assessments. The reason may be explained that the model estimates the service level considering the width of bicycle roads and the number of conflicts simultaneously besides pedestrian volume.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.5
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• pp.537-546
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• 2013

Traffic congestion in existing tunnels has increased due to increased traffic volume and enlarged vehicles. Enlarging existing tunnels has advantages over constructing new tunnels by reducing land purchasing costs as well as minimizing natural environment destruction. In fact, many overseas projects for enlarging existing tunnels have been reported. Thus, it appears that the demand on enlarging existing tunnels continues to rise in Korea in near future. Nonetheless, the studies related to the enlarged tunnels have been relatively rare since there have been few tunnel enlargement projects in Korea. In the present study, the tunnel behavior and the stability of rock pillar when enlarging existing parallel tunnels were investigated by performing FE analysis and using existing theory and empirical relationships. Four different enlarging cases, depending on the enlargement types and directions, were examined in the study. According to the results, for the tunnels with the same pillar width after enlarged, the uni-laterally enlarged tunnel indicated 5 to 20% higher crown settlement compared to the bi-laterally enlarged tunnel, and for the tunnel with the narrowest pillar, the highest shotcrete stress was observed. Also, the strength/stress ratio for rock pillar was more than 1.0 for all four enlargement cases, and the Matsuda's method was found to give higher strength/stress ratio by about 50% compared to the Peck's method.