• Journal of the Korean Society for Railway
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• v.17 no.4
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• pp.307-312
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• 2014

This study suggested the ARIMA model taking into consideration the seasonal characteristic factor as a method for efficiently forecasting passenger transport demand of the Joongang Line. The forecasting model was built including the demand for the central inland region tourist train (O-train, V-train), which was opened to traffic in April-, 2013 and run in order to reflect the recent demand for the tourism industry. By using the monthly time series data (103) from January-, 2005 to July-, 2013, the optimum model was selected. The forecasting results of passenger transport demand of the Joongang Line showed continuous increase. The developed model forecasts the short-term demand of the Joongang Line.

• Bulletin of the Korean Chemical Society
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• v.33 no.4
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• pp.1183-1189
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• 2012

The KOrea Insecticide Exposure Model (KOIEM) was developed to facilitate ecological risk-based management of Korean insecticides. KOIEM, applied as a multimedia fate model, evaluates water, soil, air, and vegetation compartments based on three water-body types (streams, ditches, and ponds). Deltamethrin, a pyrethroid insecticide, was used to evaluate and create the model parameters. After exposure of both the stream and the ditch to deltamethrin, the KOIEM-predicted concentrations and the observed levels were in agreement. The model was also evaluated using the accuracy factor (AF), which was 4.32 and 0.35 for the stream and ditch, respectively. Ecological risk assessment was also performed to evaluate the application of KOIEM for four popular South Korean insecticides (cypermethrin, deltamethrin, diazinon, and permethrin). Despite the insecticides having low PECs in water, their risk quotients were typically above 1.0. Thus, KOIEM modification would be required in further studies to account for spatial variation.

• Journal of Korea Water Resources Association
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• v.39 no.11 s.172
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• pp.977-984
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• 2006

The parameters in the Horton's model which has well known as typical infiltration model were determined by the use of the optimization technique. It was assumed the initial infiltration capacity in this model was related to the antecedent precipitation per 10 days with linear combination. And both the parameters of the ultimate infiltration capacity and the decay factor were determined uniquely on a basin. Thus the optimal model's parameters representative to a basin were obtained and the Horton's infiltration equations by rainstorm events were determined. The data of ten rainstorm events for this study were observed at the Jeonjeokbigyo station located at the Selmacheon experimental basin that was $8.5km^2$ wide in the Imjin river.

• International Journal of Railway
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• v.3 no.2
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• pp.60-67
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• 2010

This paper deals with an experimental study on the wheel flange climbing of railway vehicles, which is a major factor leading to derailment. An experiment is carried out on a 1/5-scale model wheelset of a truck used on a standard-gauge track, which is placed on a roller rig. The lateral external force acting on the wheelset is ramped up until derailment occurs under the condition of a fixed attack angle and wheel-load unbalance ratio. Three parameters, the height of wheel lift, the lateral force, and the wheel load acting on the outer rail, are measured until derailment occurs. From these measurements, it is possible to observe the behavior of the wheelset and to elucidate how the attack angle, the wheel-load unbalance ratio and the lateral external force affect flange-climb derailment. Then, a numerical simulation is carried out using an analytical model based on a single wheelset. As a result, the flange-climb behavior observed in the experiment can be explained theoretically on the bases of the analytical results, although further improvement of the model is desired.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.3
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• pp.24-35
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• 1995

In this paper, we study the Spectrum Use Measure(SUM) model for quantifying the extent of spectrum use by existing radio communication systems. This model calculates the interference level between transmitters and receivers by applying the EMC analysis technique of interference prediction process such as antenna radiation pattern model and propagation model which are well known. While several previous works have described the spectrum resources by constructing the interference contours around existing radio systems, the SUM technique is developed for quantifying and portraying the spectrum resources used by radio communication systems in a geographic area. Computer simula- tion results are illustrated to verify the calculations for the Spectrum Use Bandwidth(SUB) and Spectrum Use Factor (SUF) performed by the SUM model and find the usefulness of the SUM model.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.125-134
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• 2003

In this study, Mooney-Rivlin 1st model and Mooney-Rivlin 3rd model are adopted as strain energy density functions of the rubber compounds of a radial tire. It is shown that the FE analysis using Mooney-Rivlin models for rubber compounds may provide good approximations by employing the appropriate strain range of experimental stress-strain data in a way to describe the stress-strain relationship accurately. Especially, Mooney-Rivlin 3rd model gives an accurate stress-strain relationship regardless of the fitting strain range used within the strain of 100%. The static nonlinear FE analysis of a tire inflation is performed by employing an axisymmetric model, which shows that the outside shapes of the tire before and after inflating the tire agree well with those of the real tire. Additionally, the deformations at crown center and turning point on sidewall, distribution of belt cord force, interlaminar shear strain are predicted in terms of variation of belt cord angle which is known as the most influential factor in inflation behavior of a tire.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2003.05a
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• pp.214-225
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• 2003

Now a day, the company must strengthen the contact-point of the customer who the company has and has to block the secession of the customer by providing services or goods on time. Under this market situation, the corporation extends the CRM for the customer management and strategic management, and set the CRM-strategies up for managing the customer relationship. For this, the present enterprise's level and the business-ability for the management of the customer relationship should be considered. Therefore, in this study, we will analyze the critical factors to set the CRM up as a strategy by studying the literature review. In the critical factors, the factors of enterprise level as well as the technical factor will be included. Secondly, as you know, the BSC is used to evaluate the corporation as a index. In this study the BSC model is changed and rearranged for the applied BSC model to measure the C3M level of companies. Thirdly, based on the model developed, the factors in the first step are classified by levels and weighted values are calculated by using AHP method. As a result, we will show the diagnostic model for check the operational performance of management, marketing and sales etc.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.237-249
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• 2021

Indonesia has successfully increased its ranking to 40th place in the 2019 Travel & Tourism Competitiveness Index. While tourism has become the country's second largest foreign exchange contributor, there is no existing competitive advantage model for Indonesian tourist destinations. The purpose and novelty of this study is to develop and formulate a competitive advantage model for Indonesia's tourism industry. The model will be based on the supply-side perception analysis of competitiveness indicators from Bali and five designated super-priority destinations in Indonesia. This model is expected to become a guideline for policymakers to design an effective and focused strategy. Data were obtained from in-depth interviews with, and questionnaires given to, 62 qualified industry players from the public and private sectors. This data-driven approach builds a relationship between competitiveness indicators and competitive advantages using a combination of importance-performance analysis and confirmatory factor analysis, thereby leveraging these advantages to generate a strategic model to compete in the international tourism industry. This would also be the first study to use this method in defining the competitive advantage of a destination. Using structural equation modeling, the study found that there are 54 indicators representing twelve dimensions of competitive advantages with good fit criteria.

• Journal of Korean Association for Spatial Structures
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• v.20 no.4
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• pp.159-167
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• 2020

The resilience performance evaluation method of a structure can evaluate the ability to recover after an earthquake disaster, and this study deals with the consideration and introduction of the resilience performance evaluation method. The resilience evaluation method can be expressed as a quantified number by constructing a loss estimation model and a recovery evaluation model. The recovery evaluation model should consider downtime in addition to the repair time, and the loss estimation model should consider not only direct loss to structures and non-structures, but also indirect loss due to functional loss of the building. In addition, to build a loss estimation model, the structure should be simplified to perform an efficient analysis. Therefore, in this study, the equivalent terminal induction system proposed cantilever-type and rahmen-type SDOF, and it is evaluated somewhat conservatively compared to the example structure, and it is judged that there is a need to improve the hysteresis characteristics by applying the stiffness reduction factor of the SDOF model.

• Korea Trade Review
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• v.44 no.1
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• pp.75-86
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• 2019

This study performs a factor analysis that affects the bunker oil price using the Co-integration model and Vector Error Correction Model (VECM). For this purpose, we use data from Clarkson and the analysis results show 17.6% decrease in bunker oil price when the amount of crude oil production increases at 1.0%, 10.3% increase in bunker oil price when the seaborne trade volume increases at 1.0%, 1.0% decrease in bunker oil price when total volume of vessels increases at 1.0%, and 0.003% increase in bunker oil price when 1.0% increase in world GDP, respectively. This study is meaningful in that this study estimates the speed of convergence to long-term equilibrium and identifies the price adjust mechanism which naturally exists in bunker oil market. And it is expected that the future study can provide statistically more meaningful econometric results if it can obtain data during more long-periods and use more various kinds of explanatory variables.