• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.4
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• pp.373-380
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• 2010

An interest is increased of environment and energy so, importance on railroad high energy efficiency is magnified. And after Gyeong-bu High speed rail is completed, share rate freight transportation of railroad is expected to be gradually increased due to expand investment for railroad and operate mainly freight transportation on convention line. Therefore a research on DMT freight cars is necessary under like this situation. In paper, we developed analysis model for DMT freight car and DMT freight was analyzed numerically using VI-Rail in each condition of railway having different curve and carried out vibration analysis on curving using developed analysis model. And we carried out test on driving stability follow changing curve radius then measure against UIC code 518.

• Journal of Navigation and Port Research
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• v.40 no.5
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• pp.337-343
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• 2016

The core decisions of bulk shipping businesses can be summarized as the timing and the choice of period for which carrying capacity is traded. In particular, frequent decisions to trade freight either with repeated spot transactions or with a one-off long-term deal critically impact business performance. Even though a variety of freight trading strategies can be employed to facilitate the decisions, chartering practitioners have not been active in utilizing these strategies, and academic research has rarely proposed applicable solutions. The specific properties of freight as a tradable commodity are not properly reflected in existing studies, and limitations have been reported in their application to the real world. This research focused on the establishment of applicable freight trading strategies by taking into account two properties of freight: time perishability and term-dependant pricing. In addition to traditional trading strategies, artificial neural networks were applied for the first time to the test of freight trading strategies. The performances of the trading strategies were measured and compared to produce a remarkable outperformance of the ANN. This research is expected to make a significant contribution to chartering practices by enhancing the quality of chartering decisions and eventually enabling the effective management of freight rate risk. In addition to methodological expansion, the result will propose a way to approach the controversial issue of freight market efficiency.

• Journal of Korea Port Economic Association
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• v.32 no.2
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• pp.59-71
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• 2016

This study empirically examines the dynamic specification of the ship price model based on a vector autoregressive model and data covering from January 2000 to October 2014. Our results are summarized as follows: first, the relationship between ship price and interest rate shows significantly negative and the relationship between ship price and freight rate shows positive. It provides consistent implication that ship price depends on interest rate and freight rate under the dynamic Gordon model. Second, we apply an impulse response analysis to ship price and find the responses of the ship price from both factors, interest rate and freight rate, which affect during seven periods approximately. Finally, the results of a variance decomposition indicate that freight rate is more important than interest rate on the ship price.

• Journal of the Korean Society for Railway
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• v.7 no.1
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• pp.49-54
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• 2004

Particularly derailing freight wagon, which are loaded with dangerous chemicals, has large damages on humans and environment. In this paper the dynamic characteristic of the laminated leaf spring under extreme situation, for example derailment, is examined. The leaf spring has a static hysteresis. Not only the friction value, but also the spring rate are influenced by this hysteresis characteristic. Because of the static hysteresis of the leaf spring the spring rate must be used in normal operation depending upon the loading and the kind of the excitation with the up to 10-fold value of the static spring rate. Some characteristics of the leaf spring can be treated like well-known viscous damping, but fer special situation (preload and/or excitation) particular calculation are necessary.

• Journal of Navigation and Port Research
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• v.43 no.2
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• pp.134-141
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• 2019

The objective of this study was to establish whether global macroeconomic indicators affect the profitability of Korean shipping companies by using panel regression analysis. OROA (operating return on assets) and ROA (ratio of net profit to assets) were selected as proxy variables for profitability. OROA and ROA were used as dependent variables. The world GDP growth rate, interest rate, exchange rate, stock index, bunker price, freight, demand and supply of the world shipping market were set as independent variables. The size of the firm was added to the control variable. For small-sized firms, OROA was not affect by macroeconomic indicators. However, ROA was affected by variables such as interest rates, bunker prices, and size of firms. For medium-sized firms, OROA was affected by demand, supply, GDP, freight, and asset variables. However, macroeconomic indicators did not affect ROA. For large-sized firms, freight, GDP, and stock index (SCI; Shanghai Composite Index) have an effect on OROA. ROA was analyzed to be influenced by bunker price and SCI.

• Journal of Convergence for Information Technology
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• v.9 no.12
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• pp.47-53
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• 2019

The purpose of the study was to utilize VECM(Vector Error Correction Model) and detect causal relationships among shipping freight rates. Shipping freight rates used in this study were BDI(Baltic Dry Index), HRCI(Howe Robinson Containership Index), WS(World Scale rate) and SCFI(Shanghai Containerized Freight Index). Using weekly data published since August 2nd, 2013 to September 6th, 2019, it was discovered that BDI and WS were heavily influenced by past week's BDI and WS respectively. VECM also found that one percent increase in WS resulted in 0.022% increase in following week's HRCI data. One percent increase in HRCI affects SCFI by 0.77% on the following week. This study believes that finding may help each shipping market of shipping freight rates estimates, thereby encouraging decision markers to exercise discretion and establish best interest decision.

• Journal of Korea Port Economic Association
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• v.38 no.4
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• pp.13-23
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• 2022

In this study, from January 2015 to April 2020, we propose a stochastic volatility model to capture the leverage effect on daily freight yields in the dry cargo market and analyze the freight yields. Estimation involving the Bayesian Markov Chain Monte Carlo method for the leverage effect based on the negative correlation that exists between returns and volatility in stochastic volatility analysis yields similar estimates, and the statistcs indicates significant. That is, the results of the empirical analysis show that the degree of correlation between returns and volatility, and the magnitude and sign of fluctuations differ, which suggests that taking into account the leverage effect in the SV model improves the goodness of fit of the estimates. In addition to the statistical significance of the estimated model's leverage effect, the analysis by log predictive power score presents the estimated results with improved predictive power of the model considering the leveraged effect. These astatistically significant empirical results show that the stochastic volatility model considering the leverage effect is important for freight rate risk modeling in the marine industry.

• Journal of Ocean Engineering and Technology
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• v.14 no.2
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• pp.117-120
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• 2000

In the Step of preliminary ship design a designer should decide a economic ship. The economic ship has the least building cost to a annual freight amount satisfying a given design condition That is RFR is minimum among alternatives.

• Journal of the Korean Geographical Society
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• v.45 no.6
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• pp.766-787
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• 2010

This study seeks to clarify the process of development and the change of freight flows in the influence areas of Pyeongtaek and Dangjin Port, which opened lately. The results of analysis are as follows: from development period to growth period, the relation between the development of the port and the change of the hinterland and foreland shows no great change and the freight concentration rates of the first hinterland and foreland decreased, but those of periphery region increased. While the composition rate of import and export freight of vehicle, fuel and energy decreased, the rate of imported freights (iron or steel, other textile articles, rag and organic compounds) and exported freight (manufacture of basic metals) increased. The reasons for such changes in influence areas of port were the increase of export to China and the U.S.A. in the development period, the increase of import from China in the growth period and the diversification of nations from which fuel and energy were imported.

• Journal of Distribution Research
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• v.4 no.3
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• pp.1-22
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• 2000

Many foreign freight forwarders make inroads into domestic markets. Korean freight forwarders are not competitive on th domestic logistics area because of higher customer services by foreign freight forwarders in Korea. The purpose of this research is to analyze degree of satisfaction on customer services attributes of freight forwarders in Korea, and to strengthen the competitiveness of customer services by Korea freight forwarders in contrast to foreign investment freight forwarders in Korea. The results of the research could be summarized as follows.: When freight forwarders are selected, the most important customer service attributes have been ranked in order with 'the accuracy management of shipping order' , the reasonable offers of freight rate' and 'the quick arrangement of vessels' when freight forwarders are selected.