• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.1
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• pp.47-55
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• 2017

As preliminary work for the establishment of a harmonized ship hand signal standard, this paper explores the availability of hand signals as a means of shipboard work communication and considers the validity of standardization. Prior to the feasibility study, shipboard work activities that use hand signals were classified based only on ship safety managers' arbitrary decisions. This survey was carried out to measure shipboard workers' willingness to communicate with hand signals and their preferences regarding the institutional standardization of a hand signal framework if they engage in activities classified as relevant. The results of statistical analysis (a t-test and correlation analysis) showed that respondents are willing to accept harmonized hand signals regardless of both their work type (crew/safety supervisors) and work department (deck/engine room) under working situations where hand signals are an available means of communication. In addition, there was a significant difference in the extent of shipboard workers' frequency of hand signal usages between each type of work activity, indicating a significant positive (+) correlation between frequency of usage and preference for standardization. Finally, it was concluded that shipboard work communication would be effectively improved if a follow-up study is carried out to establish prioritized harmonized hand signal standards for port-related work activities, such as crane operation, windlass/winch operation, line movement/delivery and cargo hold operations.

• Progress in Medical Physics
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• v.13 no.1
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• pp.21-26
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• 2002

A practical calculation algorithm which calculates the relative output factor(ROF) for irregular shaped electron field has been developed and evaluated the accuracy of the algorithm. The algorithm adapted two-source model, which assumes that the electron dose can be express as sum of the primary source component and the scattered component from the shielding block. Original two-source model has been modified in order to make the algorithm simpler and to reduce the number of parameters needed in the calculation, while the calculation error remains within clinical tolerance range. The primary source is assumed to have Gaussian distribution, while the scattered component follows the inverse square law. Depth and angular dependency of the primary and the scattered are ignored ROF can be calculated with three parameters such as, the effective source distance, the variance of primary source, and the scattering power of the block. The coefficients are obtained from the square shaped-block measurements and the algorithm is confirmed from the rectangular or irregular shaped-fields used in the clinic. The results showed less than 1.0 ％ difference between the calculation and measurements for most cases. None of cases which have bigger than 2.1 ％ have been found. By improving the algorithm for the aperture region which shows the largest error, the algorithm could be practically used in the clinic, since one can acquire the 1011 parameter's with minimum measurements(5∼6 measurements per cones) and generates accurate results within the clinically acceptable range.

• Journal of Radiation Protection and Research
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• v.30 no.1
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• pp.39-44
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• 2005

A new developing reactor isn't fixed the structure and the materials of reactor components. To perform the shielding analysis for a reactor vessel by $R-\theta$ geometry, it takes much effort and time to modeling of source term according to the change of reactor components every time. Therefore, we developed the shielding analysis system for the reactor vessel by $R-{\theta}$ geometry, which wasn't affected by the reactor core geometry. By using the developed shielding analysis system, we performed the shielding analysis for the reactor vessel of an integral reactor which has the hexagonal geometry of nuclear fuel assemblies in reactor core. We compared the results obtained from the developed system with those obtained from MCNP analysis. Because the results of developed shielding analysis system were more conservative than those of MCNP calculation, it is useful for shielding analysis. As we had developed the new shielding analysis system for a reactor vessel by $R-{\theta}$ geometry, we reduced error of model for reactor core which was formerly designed by hand and saved the time and the effort to design source term model of reactor core.

• Journal of Radiation Protection and Research
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• v.31 no.3
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• pp.155-164
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• 2006

It is judged that there could be certainty in every process of analyzing environmental samples using Liquid Scintillation Counter. Therefore, this study focuses on quantitative evaluation on uncertainty in an effort to analyze comparatively accurately environmental samples. For this, after parameters which can have an effect on uncertainty was derived, the evaluation on each parameter was tamed out. The results of analysis of each parameter showed that the effect according to the weight difference of Teflon vial did not appear, and that standard deviations of SQP(E) averages reached saturation point at $75{\sim}90$ sec at the result of making increases step by step the irradiation time of External standard, and that values measured by repeat method produces good results compared with replicate. Also, conclusion was derived that analysis on sample after it is left in cold and dark room at least above 1,000 minutes have to be carried out, and the result of carrying out verification on results measured as well as equipment itself using radioactivity-error-analysis and chi-square test, resonable result was derived.

• Journal of Radiation Protection and Research
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• v.31 no.3
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• pp.129-134
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• 2006

A TL pellet for a neutron dose measurement (KCT-306) by embedding a $^6Li$-compound into a $CaSO_4:Dy$ phohphor was developed based upon the technical information of KCT-300. The KCT-300 is an another kind of $CaSO_4:Dy$ TL detector shich was developed at KAERI, in which small amounts of $NH_4H_2PO_4$ have been emvedded as a binding material. This paper presented the optimized manufacturing condition of KCT-306 and compared its sensitivity with that of the commercialized neutron TL pellets. $CaSO_4:Dy$ Phosphor with grain size ranging less than $45{\mu}m$ are used for the KCT-306. The optimum $CaSO_4:Dy$ TL phosphor, $^6Li$-compounds and P-compound as the binding material are determined as 20-40wt%, 50-70wt% and 20wt%. The TL pellet combination of our KCT-306/KCT-300, TLD-600/TLD-700 and TLD-600H/TLD-700H(Harshaw) have been irradiated in the neutron/gamma mixed fields from a $D_2O$ moderated $^{252}Cf$ neutron source. The KCT-300, TLD-700 and TLD-700H were used at the same time as gamma ray discriminators in the neutron/gamma mixed fields. It was found that the neutron/gamma response ratios of KCT-306/KCT-300, which were developed in this study, were approximately 4 times higher than those of the commercial TLD-600H/TLD-700H.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.5
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• pp.543-551
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• 2014

This study has searched to find a program in order to manage simply and practically use the expelled AtoN database from the AtoN Simulator and to support the idea decision for the AtoN placement. It examines a program that manages AtoN database through the hierarchy structure, history card and endowment with condition same as a scenario. And accomplishes this study's goal owing to realizing AtoN operational software that helps for visual, hearing sense, fixed amount verification upon AtoN placement project. The AtoN operational software contributes not only flexible control like a newly establishment, relocation etc, but also supports idea decision for AtoN placement plan through many functions such as condition search, virtual sailing and fixed amount appraisal result exhibition, etc. Through utilization of this, it is to help upon the presupposition of the impact to ship or sailor about many designs and in addition, upon the judgment of whether or not for the efficiency and appropriation of the design. It is expected to reduce possible failure costs and management costs due to AtoN design and placement plans, because to compare more various designs thru the easier verification method.

• Food Science and Preservation
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• v.24 no.1
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• pp.116-124
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• 2017

In this study, we compared the antioxidant and immuno-modulatory effects of water (HR, HL, HS), 70% ethanol (ER, EL, ES), and 70% methanol (MR, ML, MS) extracts of different parts (root, leaf, and seed) from Glehnia Radix. Yields were 17.40-30.17% for water extract, 11.47-28.67% for 70% ethanol extract, and 10.73-30.57% for 70% methanol extract, respectively. The total polyphenol and flavonoid contents of EL were 10.79 g/100 g and 2.01 g/100 g, respectively. The DPPH and ABTS radical scavenging activities of EL at $1,000{\mu}g/mL$ were 84.70% and 57.64%, respectively. The superoxide radical scavenging and ferric-reducing antioxidant power of EL at $1,000{\mu}g/mL$ were 84.05% and $975.28{\mu}M$, respectively. Moreover, 70% ethanol and 70% methanol extracts of root from Glehnia Radix significantly inhibited production of NO in LPS-stimulated macrophage RAW 264.7 cells without cytotoxicity. These results suggest that 70% ethanol and 70% methanol extracts of Glehnia Radix leaf may be a useful functional food material in the food industry.

• KSBB Journal
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• v.21 no.2
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• pp.90-95
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• 2006

Escherichia coli harboring pAC-LYCO4 and pDdxs was used for lycopene production. Three wild type strains of E. coli OW1, MG1655, and W3110 were compared with DH5${\alpha}$ used before for lycopene production. Lycopene productivity of E. coli MG1655 was similar to DH5${\alpha}$ and the highest among those wild type strain. Therefore, MG1655 strain was used for random transposon and NTG mutagenesis to increase lycopene productivity. Through transposon mutation, five transposon mutants with increased lycopene productivity were obtained. It was found that genes knocked out by transposon insertion were treB in Tn1 mutant, B2436 in Tn2 mutant, and rfaH in Tn3, 4, and 5 mutants. Lycopene productivity was the highest in Tn4 mutant among the Tn mutants, which was 6-fold and 8-fold higher in lycopene concentration and content, respectively, in comparison with those obtained with wild type strain. NTG4 mutant was acquired with NTG mutation. The highest lycopene productivity of 6 mg/L and 4 mg/g DCW was obtained from the NTG4 mutant when arabinose of 0.013 mM was added for induction of dxs, rate-limiting gene of MEP pathway. The lycopene productivity of NTG4 mutant was increased 18-fold and 12-fold in lycopene concentration and content, respectively when comparing with the wild type strain.

• Journal of Navigation and Port Research
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• v.41 no.6
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• pp.451-466
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• 2017

Deep-sea fishing vessel No. 501 Oryong was fully flooded through its openings and sunk to the bottom of the sea due to the very rough sea weather on the way of evasion after a fishing operation in the Bearing Sea. As a result, many crew members died and/or were missing. In this study, a full-scale ship flooding sinking simulation was conducted, and the sinking process was analyzed for the precise and scientific investigation of the sinking accident using highly advanced Modeling & Simulation (M&S) system of Fluid-Structure Interaction (FSI) analysis technique. To objectively secure the weather and sea states during the sinking accident in the Bering Sea, time-based wind and wave simulation at the region of the sinking accident was carried out and analyzed, and the weather and sea states were realized by simulating the irregular strong wave and wind spectrums. Simulation scenarios were developed and full-scale ship and fluid (air & seawater) modeling was performed for the flooding sinking simulation, by investigating the hull form, structural arrangement & weight distribution, and exterior inflow openings and interior flooding paths through its drawings, and by estimating the main tank capacities and their loading status. It was confirmed that the flooding and sinking accident was slightly different from a general capsize and sinking accident according to the simple loss of stability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.821-828
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• 2011

This paper developed the algorithm for improving the performance the auto pilot in the autonomous vehicle system consisting of the Track keeping control, the Automatic steering, and the Automatic mooring control. The automatic steering is the control device that could save the voyage distance and cost of fuel by reducing the unnecessary burden of driving due to the continuous artificial navigation, and avoiding the route deviation. During the step of the ship autonomic navigation control, since the wind power or the tidal force could make the ship deviate from the fixed course, the automatic steering calculates the difference between actual sailing line and the set course to keep the ship sailing in the vicinity of intended course. first, we could get the transfer function for the modeling of ship according to the Nomoto model. Considering the maneuverability, we propose it as linear model with only 4 degree of freedoms to present the heading angle response to the input of rudder angle. In this paper, the model of ship is derived from the simplified Nomoto model. Since the proposed model considers the maximum angle and rudder rate of the ship auto pilot and also designs the Fuzzy controller based on existing PID controller, the performance of the steering machine is well improved.