• Journal of Navigation and Port Research
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• v.32 no.9
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• pp.711-716
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• 2008

Marine accidents related to the tug-barges are frequent recently, such as oil spill caused by collision between oil tankers and tug-barges. There are many causes of these accidents, but poor working condition of operators takes up a considerable part of most causes. That is, the danger of accidents caused by fatigue accumulation exists in tug-barges of less than 200 gross tonnage engaged on near-coastal voyages or short shipping, because of the long-distance navigational watch by only one master. This paper aims to deduce problems of human element part out of the plan of sqfe navigation, and to propose legal amendments for preventing marine accidents by tug-barges.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.1097-1100
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• 2005

This study explored the ridership pattern between Seoul and Busan after the introduction of KTX in 2004. Since the KTX opening, average daily passengers on the Kyungbu lines have increased. These figures clearly indicate that the transportation network is becoming railroad-centric. However, the operation. of the KTX will leave many existing Saemaul and Mugunghwa train sets idle, which will be put into operation for areas, not covered by the KTX. Statistics show that the railroad ridership is clarified the distinction between train service levels. So, our paper studied the change of market share by service levels between Seoul-Busan line which is a long distance route.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.102-108
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• 2000

Due to the rapid increase of long-distance transportation, particular attentions have been paid to truck tires, especially to their dynamic characteristics. In this research, experimental modal analysis on two kinds of light-truck tires, i.e., radial tire and bias tire, are performed by using GRFP(global rational fraction polynomial) method to investigate differences of the dynamic behavior of the two tires. The test results have shown that the modal frequencies of bias tire are much higher than their corresponding values of radial tire with a similar mode shape, which is in accordance with the fact that the radial rigidity of bias tire is higher than that of radial tire. And most of the modal decay rates of bias tire are larger than those of radial tire within the scope of this experiment. In the frequency domain range of test, the bias tire has extra modes, which do not occur in the radial tire. This difference is based on the fact that the circumferential rigidity of the bias tire is quite low whereas that of radial tire is so high that the frequencies of the corresponding modes are out of the frequency range of test.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.390-398
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• 2008

While road traffic of sharp rise of an international oil price and capital Seoul reaches to critical point, and a use passenger drives recklessly on the subway which is a cradle of public transportation, the depths analyzes an electric power feed system regarding a ground wealth electric car line of the subway Line 2 East Section which is a long distance (Seongsu $\sim$ Gangbyeon), and future, electric power supply Feeder Distribution Center prepares to Operational Headway shortening along an ATO signal method change by feeder increase supplement, and ensure safety to an electric power supply system, and will solve inconvenience of safe operation and use passenger.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.7
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• pp.760-770
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• 2013

Detecting grammatical errors from a text is a long-history application. In this paper, we compare the performance of two grammatical error detection techniques, which are implemented as a sub-module of an automated English scoring system. One is to use a full syntactic parser, which has not only grammatical rules but also extra-grammatical rules in order to detect syntactic errors while paring. The other one is to use a finite state machine which can identify an error covering a small range of an input. In order to compare the two approaches, grammatical errors are divided into three parts; the first one is grammatical error that can be handled by both approaches, and the second one is errors that can be handled by only a full parser, and the last one is errors that can be done only in a finite state machine. By doing this, we can figure out the strength and the weakness of each approach. The evaluation results show that a full parsing approach can detect more errors than a finite state machine can, while the accuracy of the former is lower than that of the latter. We can conclude that a full parser is suitable for detecting grammatical errors with a long distance dependency, whereas a finite state machine works well on sentences with multiple grammatical errors.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.1
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• pp.25-31
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• 2017

The optimum temperature and salinity for long-distance transportation of rockfish Sebastes schlegeli were investigated by assessing hematological characteristics and hemocyte mortality. The possible effects of the interaction of temperature and salinity on these attributes were also investigated. No significant difference was found in hematocrit and hemoglobin among experimental conditions. Glucose levels were highest in fish exposed to salinities of 34 psu ($4^{\circ}C$), 18 psu ($4-6^{\circ}C$) and 10 psu ($4-8^{\circ}C$). Cortisol levels were elevated in the lowest temperature group ($4^{\circ}C$), but upper limits decreased with decreasing salinity. AST and ALT increased as temperature decreased at salinities lower than 26 psu. The ratio of living cells was 99.0-99.6% in all experimental groups. The percentage of necrotic cells was highest in fish exposed to salinities of 34 psu ($4^{\circ}C$), 18 psu ($6-8^{\circ}C$), and 10 psu ($4-8^{\circ}C$). The percentage of necrotic cells decreased significantly as temperature and salinity decreased, indicating that both salinity and the interaction of salinity and temperature affected cell necrosis.

• Journal of the Korean Regional Science Association
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• v.37 no.2
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• pp.49-61
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• 2021

Long-distance commuting is a problem as people living in Gyeonggi-Incheon contitue to commute to Seoul in the Seoul metropolitan area. To solve this problem, policies in the region are aiming for a self-sufficient zone formation plan and a compact city. However, urban problems caused by such long-distance commuting continue. This appears to be due to excessive density and Seoul-dependent networks. However, existing studies have focused on individual cities despite the importance of inter-city interactions, and had limitations in not considering the characteristics of the Seoul-dependent networks. Therefore, the purpose of this study is to empirically analyze the effect of the compactness on commuter travels by comprehensively considering the interactions between cities within the region using multiple regression. As a result of the analysis, it was found that that commuting efficiency increases when a network of more than a certain size is formed, and the results imply that policies should focus on fostering network centers in Incheon and Gyeonggi regions, which are outside the metropolitan area, and consider to expand the transportation networks at the regional level.

• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.73-81
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• 2009

While various factors in passenger and freight demand analysis affect on destination choice, a key factor, in general. is an attractiveness measure by size variable (e.g., population. employment etc) in destination zone. In order to measure the attractiveness, some empirical studies suggested that disaggregate gravity model are more suitable than aggregate gravity model. This study proposes that truck travelers trip diary data among Korean commodity flow data could be used to estimate the behaviors of incorporating trip departure time, activity duration and attractiveness in destination. As a result, the main findings of size and distance variables coincide with the conventional gravity model having a positive effect of population variable and a negative effect of distance variable. Due to disaggregate gravity modeling, the unique findings of this study reports that small trucks are more likely to choose short distance and early morning, morning peak and afternoon peak departure time choice. On the other hand, large trucks are more likely to choose long distance and night time departure time choice.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.3
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• pp.94-104
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• 2016

In this study, factor and cluster analysis are used to classify characteristics of the administrative basic unit, "Dong", of the Incheon Metropolitan City. Travel characteristics of the classified groups are then analyzed through databases to provide directions of urban transportation planning. First, industrially developed administrative-dong show a high commuting volume by using cars. Thus the analysis indicated the need to staggering work-hour system and signal operating system policy. Second, commercially developed administrative-dong show heavy use of public transportation and long distance commute as well as high volume of shoppers. The analysis indicated the need to improve road infrastructure. Third, densely populated administrative-dong show a high rate of commute to work and school as well as long hours of commuting. Thus the analysis indicated the need to improve road transportation policies during rush hours. Fourth, administrative-dong with multiple characteristics feature heavy pedestrian traffic thus the study analyzed the need to improve pedestrian environment policies. Lastly, administrative-dong in close proximity to train stations feature extensive use of biking as well as high volume of shoppers and students commuting. Thus the study analyzed the necessity to have plans to enhance accessibility.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.4
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• pp.35-43
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• 2016

Recently, the pipeline system for waste transportation has been increasingly constructed as new solution for the waste collection and disposal system by constantly increasing domestic waste which issued as social problem. The pipeline system is constructed through long distance, so proper long-term monitoring system is necessary which available to detect the damage location for the effective maintenance. In this paper, the experimental study is carried out to evaluate the applicability of optical strain gauge sensor based on FBG for the long-term monitoring system. Three test parameters such as pressure leaking, blockage and deformation are considered as typical damages for real-scale pipeline test specimen. In order to measure flexural and volumetric strain and temperature, three FBG sensors are installed at each monitoring sections. From the test results, this study suggested effective methods of sensor installation and arrangement. Also the sensor spacing for the design of monitoring system using FBG sensor is derived by the correlation of distances from deformation between sensor responses.