• Proceedings of KOSOMES biannual meeting
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• 2007.05a
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• pp.101-108
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• 2007

Tugboat has carried out the important role and service in the maritime industry construction, such as port and sea bridge construction, fairway dredging and sea reclamation etc. Furthermore, tugboat takes the largest portion in number of vessel at the domestic registry and barges as big as the general merchant vessel, which are getting specialized and larger, are in operation. In spite of the increase of marine accident under this situation, there has been no proper measure for the safe navigation of tugboat in the aspect of a nation. This paper aims to propose the measure for the safe navigation of tugboat according to the frequent marine accident of tugboat with sea bridge. Therefore, we show a example of the sailing schedule and operation checklist based on the analysis of statistics and precedent of marine accident and the investigation of the actual operation state of tugboat in the aspect of a contract of carriage and a personnel setup, which should be checked by the operator of tugboat, pass through sea bridge safely and propose the safe traffic supporting system based on electronic chart system to improve the safe navigation of tugboat.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.90-96
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• 2000

The optimum cooking conditions for large scale continuous gas cooker were studied with three varieties of rice. Optimum soaking time for the cooker was estimated to be 30 min at cooking temperature above $20{\circ}C$, while 60 min at cooking temperature below $10{\circ}C$. The ratio of water-to-milled rice giving the best eating quality was founded to be $1.41{\sim}1.48$, and corresponding moisture content of cooked rice ranged from 60 to 62% for different rice varieties. The optimum ratio of water to milled rice. (Chucheong) decreased from 1.50 to 1.37 with increase in the amount of milled rice from 4.0 to 6.5 kg in a cooking vessel. However, actual water uptake by rice (g water absorbed per g rice) on cooking was nearly constant value of 1.13, which means that evaporated water during cooking increases with decreasing the amount of rice in a cooking vessel.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.2
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• pp.91-97
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• 2010

As nuclear power plants are getting older, interests on a decontaminating process are increasingly attracting more attention. Chemical decontamination is crucial to lower the production of radioactive waste and radiation dose rate. Prior to this, oxidizers and detergents for target material should be chosen so as to decontaminate major systems and components of a nuclear power plant chemically. In order to decontaminate it properly, it is crucial to have information about the chemical composition and crystalline structure of CRUD, analyzing its samples from the target or the decontamination system with components. However, there is no program which enables the extraction of samples directly from the object or the decontamination system with components carrying genuine radioactivity. Therefore, it is limited to samples from corrosion products carrying partial radioactivity as a resource. The composition of CRUD varies considerably depending on refueling cycle because it is closely related to the constituent of basic material. After settling a target, it is crucial to analyze and obtain analytical information about CRUD as a decontamination target. In this paper, various technologies for manufacturing simulated CRUD are introduced as alternatives to unattained samples. A metal oxide or metal hydroxide was used to synthesize simulated cruds having chemical compositions and crystalline stricture similar to the actual one by 12 different methods. CRUD 4(metal oxides in the autoclave vessel) and CRUD 10(metal oxides in a crucible after hydrazing pretreatment)were chosen as the best method for Type 1 and Type 2.respectively. As these CRUD can be synthesized easily without using any specialized equipment or reagents in a short time and in large quantities, they are expected to stimulate the development of decontaminating agents and processes.

• Korean Journal of Remote Sensing
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• v.39 no.6_1
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• pp.1451-1466
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• 2023

In the context of maritime emergencies, the utilization of drones has rapidly increased, with a particular focus on their application in search and rescue operations. Deep learning models utilizing drone images for the rapid detection of distressed vessels and other maritime drift objects are gaining attention. However, effective training of such models necessitates a substantial amount of diverse training data that considers various weather conditions and vessel states. The lack of such data can lead to a degradation in the performance of trained models. This study aims to enhance the performance of deep learning models for distress ship detection by developing a maritime environment simulator to augment the dataset. The simulator allows for the configuration of various weather conditions, vessel states such as sinking or capsizing, and specifications and characteristics of drones and sensors. Training the deep learning model with the dataset generated through simulation resulted in improved detection performance, including accuracy and recall, when compared to models trained solely on actual drone image datasets. In particular, the accuracy of distress ship detection in adverse weather conditions, such as rain or fog, increased by approximately 2-5%, with a significant reduction in the rate of undetected instances. These results demonstrate the practical and effective contribution of the developed simulator in simulating diverse scenarios for model training. Furthermore, the distress ship detection deep learning model based on this approach is expected to be efficiently applied in maritime search and rescue operations.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.5
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• pp.576-585
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• 2020

This study quantitatively investigated the increase in ballasting time through numerical calculations when an ultraviolet (UV) ballast water management system (BWMS) is installed on an existing vessel. The calculation results indicate that the ballasting time of a gas carrier having 55,000 dead weight tonnage was 2.152 hours without installation of the UV BWMS and implementation of a flow control function. Ballasting time increased by 14.2% after installing the UV BWMS, and it increased by 20.4% with both its installation and implementation of a flow control function. If actual conditions are taken into account, ballasting time after installing the UV BWMS is estimated to increase by at least 30% compared with current ballasting time. Therefore, when concerned parties select a UV type BWMS, it is advisable for them to minimize ship operation losses from an increase in ballasting time by considering the capacity of the actual ballast pumps on board and the flow energy loss of the UV BWMS. Additionally, it is recommended that a BWMS with larger capacity, larger pipes, and pipes with inside coatings be used to minimize the increase in ballasting time after installation of the BWMS.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.1
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• pp.15-21
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• 2020

This study analyzes the results of applying the ISO19030 (hull and propeller performance monitoring method) standard to an actual 178 k bulk vessel. Recently, there have been many attempts to apply various energy reduction solutions to vessels to continuously strengthen GHG reduction regulations and secure maritime competitiveness. However, it is not easy to quantitatively analyze the performance of a ship. To resolve these problems, shipping companies, marine paint companies, ship owners, and transportation associations have appointed specialists and standardized the ISO19030 (standard of hull and propeller performance monitoring method) guidelines in 2016 after three years of continuous review. The ISO19030 standard provides methods to monitor hull and propeller performance quantitatively through standardized procedures, thus allowing ship managers to arrive at informed decisions for hull and propeller maintenance, and to evaluate energy-saving solutions and ship-maintenance efficiency. The ISO19030 standard provides a method of analyzing the ship's own performance by collecting the ship's operation and agency data and correcting its environmental and operating factors. In this paper, we apply the ISO19030 standard to three actual ships and propose the ISO19030 application result and the improvement point of the current ISO19030 standard.

• Journal of the Korean Society of Radiology
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• v.14 no.1
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• pp.61-68
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• 2020

The purpose of this study is to investigate the correlation of blooming artifacts according to dilution ratio of contrast agent on CT angiography images. A total of 10 sets were prepared by differently setting the ratio of contrast media and saline in a ball phantom made by a 3D printer. CT scan images were obtained and reconstructed by MIP and MPR techniques to obtain axial, sagittal and coronal images, respectively. After, the diameter of the ball phantom of the image obtained after the test was measured each 30 times, a total 1800 times. As a result, the dilution of 20:80 in the coronal plane was the smallest (p<0.05). Similarly, when dilute to 20:80 in the sagittal plane of MIP, it was the smallest as 20.39 ± 0.08 mm (p<0.05). Correlation analysis between dilution ratio and measurement size confirmed strong negative correlations in all reconstructed images (p<0.05). In conclusion, the higher the dilution ratio of the contrast agent, the more difficult it is to measure actual blood vessel measurement. Therefore, this study may provide basic data in future studies on actual measurement.

• Journal of Navigation and Port Research
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• v.45 no.6
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• pp.276-283
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• 2021

The capital structure of the shipping business, which is characterized by its capital intensity and extreme market volatility, is closely related to long-term stability. Research in this area has been conducted mostly in the form of deriving the determinants of capital structure from company-wise financial ratios. This research, on the other hand, has a different approach to the topic. It identifies the relationship between actual cash profit and loss and other variables - i.e. actual vessel prices, interest rates and leverage ratio - by employing historical simulation. The result demonstrates that the P anamax cash profit shows 0 (break-even point) when the debt weight reaches 64.38% (debt ratio 180.74%) and the Cape, 73.04% (debt ratio 270.92%). Additionally, the ships of different types show a divided pattern for the pre- and post-'Super Boom'. It indicates that the business area and the market cycle should be considered when a leverage strategy is established. This research benefits shipping companies set a rational leverage strategy as well as delivers a reasonable guideline to government authorities for the development of a sound policy on shipping finance.

• Nuclear Engineering and Technology
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• v.27 no.6
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• pp.859-869
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• 1995

The present study is to understand the physical phenomena anticipated during the accident with RHR loss under mid-loop operation in a PWR and, at the same time, to examine the prediction capability of RELAP5/MOD3.1 on such an accident, by simulating an integral test relevant to this accident for reliable analysis in an actual PWR. The selected experiment, i.g. BETHSY Test 6.9a, represents the configuration with the pressurizer manway open and steam generators unavailable during the accident. Accordingly, the results of this ok are sure to contribute to understanding both the key events as well as the sensitive parameters, anticipated in the accident, for validity of the actual analysis. In the simulation result overall behavior as well as major phenomena observed in the experiment have been predicted reasonably by RELAP5/MOD3.1, however, the problem associated with enormous computing time .due to small time step size has been encountered. Besides, the code prediction of higher swollen level in the pressure vessel has given rise to overestimation of both pressurizer level and RCS pressure. Subsequently, overprediction of the break flow through the manway has led to earlier core uncovery than that in the experiment by about 400 seconds. As a whole, it is demonstrated from both the experiment and the analysis that gravity feed has not been sufficient to recover the core level and thus additional forced feed has been necessary in this configuration.

• Journal of Fisheries and Marine Sciences Education
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• v.14 no.2
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• pp.191-212
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• 2002

The economic and social bad influences of the illegal fishery bring about the results of the fishery resources exhaustion, of the fishery disorder and of the obstruction to sound management for fishery. The typical illegal fishery conducted in the coastal and offshore area of Korea can be divided as follows; fishery conducted by legally unauthorized method, fishery without permission from the Government, and fishery conducted in contravention of the laws and regulations concerning the fishing vessel, fishing gear and fishing method etc. The major reasons of origination of the illegal fishery in the coastal and offshore area of Korea are; Firstly, almost of the fishermen are poorly equipped in economical scale, Secondly, it is very easy to approach the illegal fishery because the domiciliation condition of the fishing village is deteriorated. Thirdly, almost of the fishermen are lacking in lawabiding spirit. Fourthly, the insolvent and unstable fisheries management policy with the lukewarm enforcement of the fisheries laws and regulations by the Government. Fifthly, the small scale family supporting fisheries are widespreaded. Sixthly, to retrieved the economical difficulties the fishermen are easily led astray the illegal fishery. As a conclusion the authors made some suggestions to stamp out the illegal fishery by this study. For the first, temptation fishermen into lawabiding fishery through intensification of the penal regulations is required. Second, simplification of the fishery type through combination of resemble fishing methods is required. Third, actual improvement of the fundamental fishery permission regime is required. Fourth, Introduction of the self-regulating or co-management system for the fishery management is required.