• 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.

• The Journal of Information Systems
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• v.26 no.3
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• pp.119-147
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• 2017

Purpose In an online e-commerce environment without face-to-face contact between the seller and the buyer, the attitudes of consumers differ greatly depending on which framing strategy is applied, even in cases when the benefits of the deals represent the same value. The purpose of this study is to explore the effects of price-framing and message-framing strategies on consumer attitudes through an experimental analysis in the context of online travel product purchasing. This study suggests a research model based on prospect theory and prior literature on price-framing and message-framing strategies. Design/methodology/approach The experiment was structured as a 2 (discount price presentation: 'Won' vs. '%') ${\times}$ 2 (discount level: low vs. high) ${\times}$ 2 (time-limit message: none vs. one) mixed design. The research hypotheses were tested in a study of 200 undergraduate and graduate students assigned randomly and distributed evenly to each of the eight cells. Findings The findings indicate that consumer attitudes become more favorable when the '%' discount, higher discount rate, and time-limit message are presented. However, no significant interaction effect is found between the discount price presentation and the discount level/time-limit message. This study has a theoretical implication in that it extends the scope of research by examining the influence of framing strategies on experience goods such as online travel products. Moreover, this study can provide managers with more specific guidelines when establishing framing strategies in the context of purchasing online travel products.

• Management & Information Systems Review
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• v.33 no.2
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• pp.301-315
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• 2014

The purpose of this study is to estimate the economic value of the Kumjung Mountain, using a Individual Travel Cost Model(ITCM). This paper compares Poisson and negative binomial count data models to measure the tourism demands. Interviewers were instructed to interview only individuals. So the sample was taken in 700. A dependent variable that is defined on the non-negative integers and subject to sampling truncation is the result of a truncated count data process. The results suggest that the truncated negative binomial model is improved overdispersion problem and more preferred than the other models in the study. This study emphasizes in particular 'travel cost' that is not only monetary cost but also including opportunity cost of 'travel time'. According to the truncated negative binomial model, estimates the Consumer Surplus(CS) values per trip of about 60,669 Korean won and the total economic value was estimated to be 252,383 Korean won.

• Journal of the Korean Geotechnical Society
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• v.23 no.8
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• pp.17-33
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• 2007

Downhole seismic method is widely used for obtaining shear wave velocity profile of a site because it is simple and economical. Determining accurate travel time of shear wave is very important to obtain reliable result in downhole seismic method. In this paper, comparison study of various travel time determination methods was performed. Numerical study and model chamber test were performed for effective comparison study. Signal traces were acquired by performing downhole test at each numerical simulation and soil box test. Travel time data for each signal traces were determined by using six different methods and Vs profiles were evaluated. Comparing travel time data and Vs profiles with the reference value, the first arrival picking method proved to be ambiguous and unreliable. Other methods also did not always provide accurate results and the magnitude of error was dependent on the signal to noise ratio. Cross-correlation method proved to be the most adequate method for the field application and it was verified additionally with field data.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.499-505
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• 1999

The time paramters most frequently used in hydrology are the tuime of concentration, lag time , time base, time to equilibrium , time to peak, time of travel, and residence time. Especially the time of concentraion constitute an important part of operating rainfall-runoff modeling and determining critical rainfall intensity. In the result of simulation , we discoved that SCS foumula has the highest value with length, Kerby with height and SCS with slop respectively, while only Kraven formula has the lowest value in them. With concerning to relative sensitivty, the time of concentraion was marked the constant effect according to increase of length and slope level, and the length has much more effect than the slope relatively in parameters.

• Journal of Korean Society of Transportation
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• v.16 no.4
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• pp.219-224
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• 1998

통행시간가치에 대한 신뢰구간추정 방법론을 제시하고 서울시 출근통행자의 시간가치 신뢰구간의 추정을 통하여 그 적용사례를 예시하였다. 사례분석을 통하여 서울시 출근통행자의 평균시간가치는 시간당 7,341원으로 추정되었고, 95%신뢰구간의 하한치는 5,454(원/시간), 상한치는 10,806(원/시간)으로 추정되었다.

• Journal of Korean Society of Transportation
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• v.27 no.3
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• pp.131-140
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• 2009

A diversity of railway network function enhancement projects such as the double tracking, electrification, and direct operation have been actively executed to improve the railway service. When the new rapid railway is provided, how many people will use it instead of other transports? How will the railway choice behavior be changed? Accordingly, in this paper, the applicability of diverted travel demand forecast method by Stated Preference(SP) and Transfer Price(TP) data was reviewed for Daegu metropolitan railway service. As the result of implementing the Revealed Preference(RP) and RP+SP model, the total travel time and travel cost parameters are of the right sign and are highly significant. In particular, when TP data is used as the complementary investigation of SP, the boundary value of diverted travel demand can be easily identified by railway fare and travel time service level. Therefore, it is considered that this will practically apply even in other regions as well as Daegu metropolitan railway.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.241-249
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• 2001

The objective of this paper is to develop the optimal path algorithm for dynamic route guidance system in advanced traveler information system (ATIS). The travel time is forecasted in each path between network nodes. Floyd-Warshall algorithm is used to find the optimal route based on this forecasted travel time in dynamic traffic network. This algorithm is modified to apply the real traffic network that has left-turn restriction, U-turn, and P-turn. A big value is assigned to one of arcs in turn restriction and a virtual node is used to consider U-turn and P-turn for Floyd-Warshall algorithm.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.3
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• pp.330-337
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• 2005

This study was carried out to propose the managemental improvement of the purification plants and the distribution facilities which can minimize the formation of disinfection by-products in drinking water distribution system. The disinfection by-products were highly created in the water treatment plant that the organic matters were high and the chlorine dosage was excessive. The concentration of DSPs was shown the highest value in August and the lowest value in December, because of temperature and pre-chlorine dosage effect. From the result of tracer test, the travel time from the treatment plant to the end of pipeline was around 3-4 days in summer, 5-6 days in winter, respectively, and the DSPs concentration of the reservoir(end of pipe) was 2-3 times higher than that of the beginning point. The improvement of the chlorination process and structural reformation of distribution facility was demanded to minimize the DSPs increase from purification plant to the end of pipe.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.2
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• pp.132-141
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• 2024

In this study, the differences in user satisfaction and the variables influencing the satisfaction with demand response transport (DRT) by travel purpose were compared. The purpose of DRT travel was divided into commuting/school and shopping/leisure travel. A survey conducted on 'Shucle' users in Sejong City was used for the analysis and the least absolute shrinkage and selection operator (LASSO) regression analysis was applied to minimize the overfitting problems of the multilinear model. The results of the analysis confirmed the possibility that the introduction of the DRT service could eliminate the blind spot in the existing public transportation, reduce the use of private cars, encourage low-carbon and public transportation revitalization policies, and provide optimal transportation services to people who exhibit intermittent travel behaviors (e.g., elderly people, housewives, etc.). In addition, factors such as the waiting time after calling a DRT, travel time after boarding the DRT, convenience of using the DRT app, punctuality of expected departure/arrival time, and location of pickup and drop-off points were the common factors that positively influenced the satisfaction of users of the DRT services during their commuting/school and shopping/leisure travel. Meanwhile, the method of transfer to other transport modes was found to affect satisfaction only in the case of commuting/school travel, but not in the case of shopping/leisure travel. To activate the DRT service, it is necessary to consider the five influencing factors analyzed above. In addition, the differentiating factors between commuting/school and shopping/leisure travel were also identified. In the case of commuting/school travel, people value time and consider it to be important, so it is necessary to promote the convenience of transfer to other transport modes to reduce the total travel time. Regarding shopping/leisure travel, it is necessary to consider ways to create a facility that allows users to easily and conveniently designate the location of the pickup and drop-off point.