• International Journal of Highway Engineering
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• v.16 no.4
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• pp.119-126
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• 2014

PURPOSES: Used in transportation planning and traffic engineering, almost traffic simulation tools have input variable values optimized by overseas traffic flow attribution because they are almost developed in overseas country. Thus, model calibration appropriated for internal traffic flow attribution is needed to improve reliability of simulation method. METHODS : In this study, the traffic flow model calibration is based on expressways. For model calibration, it needs to define each expressway link according to attribution, thus it is classified by design speed, geometric conditions and number of lanes. And modified greenshield model is used as traffic flow model. RESULTS : The result of the traffic model calibration indicates that internal congested density is lower than overseas. And the result of analysis according to the link attribution indicates that the more design speed and number of lanes increase, the lower the minimum speed, the higher the congested density. CONCLUSIONS: In the traffic simulation tool developed in overseas, the traffic flow is different as design speed and number of lanes, but road segment don't affect traffic flow. Therefore, these results need to apply reasonably to internal traffic simulation method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.712-717
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• 2011

Option issuers generally utilize Dynamic Delta Hedging(DDH) technique to avoid the risk resulting from continuously changing option value. DDH duplicates payoff of option position by adjusting hedge position according to the delta value from Black-Scholes(BS) model in order to maintain risk neutral state. DDH, however, is not able to guarantee optimal hedging performance because of the weaknesses caused by impractical assumptions inherent in BS model. Therefore, this study presents a methodology for dynamic option hedge using artificial neural network(ANN) to enhance hedging performance and show the superiority of the proposed method using various computational experiments.

• Journal of Korean Society of Transportation
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• v.26 no.3
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• pp.17-29
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• 2008

A volume-delay function(VDF) has been used to describe the relation between traffic volumes and delay experienced by travelers on the roads traveling from origin to destination, which has been usually adopted in traffic assignment. For the purpose of more precise description of traffic pattern, we have to estimate the parameters of VDF in advance. This paper presents a methodology for estimating the parameters, which combined with golden section method. By using the method we have estimated the parameters with real data based on KTDB(2006), and validated them. Compared to the existing values of the parameters, newly estimated values are found to be closer to real world.

• The Journal of Society for e-Business Studies
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• v.19 no.4
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• pp.151-168
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• 2014

UCI (Universal Content Identifier) as a national digital content identification system for identifying digital content and ICN (Integrated Copyright Number) for copyright management are operated by Korea copyright commission. However, They are not interoperable with international standard identification system such as ISRC (International Standard Recording Code), ISWC (International Standard Works Code), and ISAN (International Standard Audiovisual Number) due to lack of linkage system. Hence, extra works with international standard identification system are needed for international market entry and integrated management of statistical information including content settlement in international market is impossible. In this paper, the domestic/international identification systems are surveyed, and by metadata analysis of identification systems, linkage method with UCI/ICN is proposed. And also by developing the prototype model, research direction to UCI/ICN with international standard identification system is proposed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.269-281
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• 2018

Unlike its archetype predecessor such as the Highway Capacity Manual of the United States, the Korean Highway Capacity Manual of 2013 provides the analytical models for estimating the saturation flow rates for the lane-occupying work-zones in the proximity of the signalized intersections. Direct application of the revised saturation flow rates into the classic control delay models, however, appears to produce unreasonable delay amount as traffic demand approaches lane-group capacities and surpasses them, which is common phenomena in the work-zones. Complex interaction among vehicles, lane-dropping work-zone geometry and signal operations were never accounted in the traditional control delay models, and considerable differences between the delay model outcomes and field observations are repeatedly experienced. This paper proposes the modified approaches to the delay models in the manual, exerted on all three elements of control delay, and particularly focuses on the temporal and spatial boundary expansion in comparing the simulated results to the estimated ones. Extensive microscopic simulation work and calibration effort supports the modified approaches well enough to use them in the work-zone planning and evaluation.

• The Journal of Engineering Geology
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• v.22 no.1
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• pp.113-121
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• 2012

The mechanical characteristics of a fault gouge from near Mt. Kumjung in Kumjung-Gu, Busan, were estimated from laboratory tests on different joint models. Fault gouge samples and joint samples in biotite granite were obtained from boreholes in the study area that had penetrated small faults associated with the Dongnae and Yangsan faults. XRD and SEM analyses revealed that for the fault gouge consists of several clay minerals with tabular structure (kaolinite, montmorillonite, illite, sericite), which could cause the considerable reduction of shear strength when wet. The shear strength of the fault gouge was obtained from direct shear tests of the fault gouge itself and from direct shear tests of several natural/artificial joint surfaces coated with fault gouge. The results indicate that the reduction of shear strength is more abrupt for the joint surfaces coated with fault gouge compared with uncoated joint surfaces, and that the friction angle of the fault gouge between joint surfaces is much lower than the internal friction angle of the fault gouge itself. Fault gouges in contact with rock, therefore, could have a stronger negative effect on the stability of structures in rock masses than the fault gouge itself.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.1
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• pp.63-71
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• 2019

The two-fluid model proposed by Herman and Prigogine is useful for analyzing macroscopic traffic flow in a network. The two-fluid model is used for analyzing a network through the relationship between the ratio of stopped vehicles and the average moving speed of the network, and the two-fluid model has also been applied in the urban transportation network where many signalized or unsignalized intersections existed. In general, the average travel speed and moving speed of a network decrease, and the ratio of stopped vehicles and low speed vehicles in network increase as the traffic demand increases. This study proposed the two-fluid model considering congested and uncongested traffic situations. The critical velocity and the weight factor for congested situation are calibrated by minimizing the root mean square error (RMSE). The critical speed of the Seoul network was about 34 kph, and the weight factor of the congestion on the network was about 0.61. In the proposed model, $R^2$ increased from 0.78 to 0.99 when compared to the existing model, suggesting that the proposed model can be applied in evaluating network performances or traffic signal operations.

• Journal of Wetlands Research
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• v.22 no.2
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• pp.106-112
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• 2020

Wetlands play an important function and role in hydrological, environmental, and ecological, aspects of the watershed. Water level in wetlands is essential for various analysis such as for the determination of wetland function and its effects on the environment. Since several wetlands are ungauged, research on wetland water level prediction are uncommon. Therefore, this study developed a water level prediction model using multiple regression analysis, principal component regression analysis, artificial neural network, and DNN to predict wetland water level. Geumjeong-Mountain Wetland located in Yangsan-city, Gyeongsangnam-do province was selected as the target area, and the water level measurement data from April 2017 to July 2018 was used as the dependent variable. On the other hand, hydrological and meteorological data were used as independent variables in the study. As a result of evaluating the predictive power, the water level prediction model using DNN was selected as the final model as it showed an RMSE value of 6.359 and an NRMSE value of 18.91%. This research study is believed to be useful especially as a basic data for the development of wetland maintenance and management techniques using the water level of the existing unmeasured points.

• Journal of Korean Society of Transportation
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• v.25 no.2 s.95
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• pp.121-132
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• 2007

This paper addressed the issue of a generalized cost model for transit assignment. The model composed of walk time, waiting time (including transfer waiting time), line-haul time, transfer walk time, and fare. The weights of each component were supposed to be calculated using the stated preference (SP) data, which were collected prudently in order to reflect reality. The marginal rate of substitution and wage rate were applied to calculate the weights. The results showed that the weight of walking time per in-vehicle travel time (IVTT) was 1.507, the weight of waiting time (per IVTT) was 1.749, that of transfer time (per IVTT) was 1.474, and that of fare (per IVTT) was 1.476 for trips between inner-city areas in Seoul. Weights for each component were identified as 1.871, 1.967, 1.015, and 0.857, respectively, for trips between Seoul and Gyeonggi. Statistical significance existed between two cases and each variable was also statistically significant. Transit assignment using the relative weights estimated in this study was implemented to analyze the travel index in a macroscopic and quantitative basis. The results showed that average total travel times were 30.23 minutes and 63.29 minutes and average generalized costs were 2,510 won and 3,880 won for trips between inner-city areas in Seoul and between Seoul and Gyeonggi, respectively.

• Journal of Korean Society of Forest Science
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• v.90 no.4
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• pp.573-581
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• 2001

The purposes of this study are to estimate mean willingness to pay (WTP) for preventing forest fires by contingent valuation method (CVM), and to calibrate the variables affecting WTP. The forest fire prevention fund was utilized as a payment vehicle to elicit respondents' willingness to pay (WTP). A total of 500 adults who reside in Seoul Metropolitan area were selected by two-stage cluster sampling and conducted the face-to-face interview. The scenario was designed to meet the requirements for double-bounded dichotomous choice CVM. More than half of the respondents (64.6%) have a willing to pay for the fund. The mean WTP was \4,532. Therefore a total WTP for the population was \34,165,758,000. The calibration of Weibull proportional hazard model showed that education level, environmental conservation intention and negative consciousness about the effect of forest fire were independent variables strongly influencing the WTP.