• Journal of the Society of Naval Architects of Korea
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• v.59 no.3
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• pp.149-156
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• 2022

In order to study the open-water test and analysis techniques for pumpjet propulsors in the Large Cavitation Tunnel (LCT), at the Korea Research Institute of Ships and Ocean Engineering, a set of test equipment was designed and manufactured. The pumpjet propulsor is composed of rotor, stator and duct resulting in the strong interaction between the components. A ring-shaped sensor was developed to measure the thrust and torque for duct and stator. The test equipment including the pumpjet is installed on an existing POW dynamometer in the reverse direction. The results from the reverse POW test setup were validated against those from the conventional POW test setup in the Towing Tank (TT) as well as in the LCT. The pumpjet open-water test was conducted at the Reynolds number of around 1.0×106, at which the obtained experimental data became stable in the Reynolds number effect test. The open-water test for the rotor (rotor-only) was conducted to study whether the duct and stator should be considered as a part of the hull or the propulsor. On the basis of the test results, it was shown that the duct and stator could be included in the propulsor. The total thrust, combined thrust of rotor, duct, and stator was used for the pumpjet open-water test analysis. As the whole pumpjet is defined as a propulsor, it is thought that the self-propulsion test and analysis could be conducted in the same way as that of the conventional propeller.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.6
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• pp.391-399
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• 2021

In order to investigate force and cavitation characteristics for the flat & twisted rudders in the Large Cavitation Tunnel (LCT), the rudder dynamometer was designed and manufactured. The measuring capacities of lift, drag and moment are ±1000 N, ±2000 N, and ±150 N-m, respectively. The present dynamometer uses the actuator with a harmonic drive to control the rudder angle without backlash. As the target ship is a military ship with twin shaft, each dynamometer was installed above the port & starboard rudders. After the installation of the model ship with all appendages, the model test composed of rudder force measurement and cavitation observation was conducted for the existing flat rudder & the designed twisted rudder. While the flat rudder showed the big difference of lift & moment between port & starboard, the twisted rudder presented a similar trend. The cavitation of the twisted rudder showed better characteristics than that of the flat rudder. Another set of model tests were conducted to investigate rudder performance by the change of the design propeller. There was little difference in rudder performance for the design propellers with slight geometric change. Through the model test, the characteristics of the flat & twisted rudders were grasped. On the basis of the present study, it is thought that the rudder with better performance would be developed.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.3
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• pp.161-169
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• 2024

In order to investigate cavitation performance for the azimuth thruster in Large Cavitation Tunnel (LCT), the cavitation test apparatus was designed and manufactured. Generally the model scale is determined by the pod dynamometer with about 70mm diameter. Recently as ships with azimuth thruster have become bigger, the problem of the model ship installation was occurred. The model ship with pod dynamometer couldn't be installed in the LCT test section. The cavitation test apparatus and technique which can conduct the cavitation test without pod dynamometer were developed. The cavitation tests were conducted in torque identity method instead of thrust identity method. The target ship with azimuth thruster is 18K LNG bunkering vessel. As the full-scale ship test was conducted, the model cavitation tests were conducted at the same operating conditions. The fluctuating pressure levels of the full-scale ship were compared to those of the model tests. Another model cavitation test was conducted in the foreign institute and the cavitation observation results were compared to those of LCT. Through the comparison with the existing results, it is thought that the cavitation test for the azimuth thruster can be conducted in torque identity method.

• Journal of Life Science
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• v.17 no.3 s.83
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• pp.368-374
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• 2007

The purpose of this study was to investigate the effects of different type of triglycerides (MCT & LCT) on weight, survival time, energy substrate (FFA, TG, pyruvate, lactate), insulin and lipase in the trained rats. Fifty-four Sprague-Dawley rats were divided into 3 groups: control group (CG, n=18), MCT supplement group (MG, n=18), and LCT supplement group (LG, n=18). They also were divided into 3 periods: trained resting (R, n=6) and trained & exercise load (E, n=6), and survival time test was performed to know the supplemented effects. Body weight of all animals was checked every week, MCT group and LCT group received supplementary MCT and LCT orally and preliminary swimming training for 6 days before the start of main experiment. All animals received 15-minute swimming training 5 times during first week of experiment, and swimming training time was increased 15 minutes every week until it reached 90 minutes at last 9th week. After last swimming training, animals were fasted for 12 hours and blood samples were taken from abdominal aorta in the Department of Animal Medicine at the D university Animal Center. Among the CGE, MGE, and LGE groups, the MGE had the greatest increase in physical performance time. In the FFA levels, there was significant differences(p<.05) in CG, MG and LG groups, and also there was major difference of FFA levels in the MG and LG. In the lipase levels, there was signifi.ant differences (p<.05) in CG, MG and LG groups. MG was the greatest than the other groups. In the insulin hormone levels, there was the great differences (p<.05) in LG compare to CG groups, whereas there was no significant difference in the CG and MG. In conclusion, these results suggest that regular prolonged physical training with MCT supplementation, improves exercise performance time through the increase of energy substrate utilization, lipase activity and FFA levels, irrespective of insulin hormone responses.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.2
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• pp.914-934
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• 2016

In the mobile distributed environment, an entity may move across domains with great frequency. How to utilize the trust information in the previous domains and quickly establish trust relationships with others in the current domain remains a challenging issue. The classic trust models do not support cross-domain and the existing cross-domain trust models are not in a fully distributed way. This paper improves the outstanding Certified Reputation (CR) model and proposes a Lightweight Cross-domain Trust (LCT) model for the mobile distributed environment in a fully distributed way. The trust certifications, in which the trust ratings contain various trust aspects with different interest preference weights, are collected and provided by the trustees. Furthermore, three factors are comprehensively considered to ease the issue of collusion attacks and make the trust certifications more accurate. Finally, a cross-domain scenario is deployed and implemented, and the comprehensive experiments and analysis are conducted. The results demonstrate that our LCT model obviously outperforms the Bayesian Network (BN) model and the CR model in our cross-domain scenario, and significantly improves the successful interaction rates of the honest entities without increasing the risks of interacting with the malicious entities.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.1
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• pp.34-42
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• 2015

The development of an azimuth thruster which has the function of dynamic positioning and propulsion has been greatly required as the demand of vehicles with it increases. To develop or design a reliable azimuth thruster, it is appropriate that the performance and cavitation observation tests should be conducted in the regime of high Reynolds number. In the present study, to satisfy high Reynolds number condition new dynamometer for a large azimuth thruster is manufactured and arranged in the test section of the Large Cavitation Tunnel (LCT). The test method composed of the open water and the cavitation observation tests is established successfully in LCT, considering the thruster design.

• Journal of Korean Clinical Health Science
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• v.7 no.1
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• pp.1205-1214
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• 2019

Purpose: To investigate the effect of color soft contact lenses on the corneal thickness in young Korean population. Methods: The subjects consisted of 112 eyes (7 males, 49 females) with the mean age of $20.987{\pm}1.093years$ (range 20-25 years) in young Korean population during 2018. Test was compared the corneal thickness before and after wearing color soft contact lenses. The thinnest cornea thickness(TCT), central cornea thickness(CCT), pupil centre thickness(PCT), superior corneal thickness(SCT),inferior corneal thickness(ICT), medial corneal thickness(MCT), lateral corneal thickness(LCT) of the cornea was measured using the Pentacam pachymetry. The statistically analysis was perform the Shaparo-Wilk test. Results: The right eye was a statistically significant among the CCT,LCT, MCT and TCT values(p<0.001) in the compared the corneal thickness before and after wearing soft colour contact lenses. Also the left eye was a statistically significant among the LCT and MCT values(p<0.001) in the compared the corneal thickness before and after wearing soft colour contact lenses. However, there was no statistical difference (p>0.5) in the mean PCT between before and after wearing color soft contact lenses. Conclusion: These results suggested that the color soft contact lens wear can the effect the regional thickness of cornea. Therefore, the analysis of corneal topography with Pentacam can provide correct and useful diagnostic information of the morphology of the RGP contact lens fitting and diagnosis of corneal refraction surgery.

• Bulletin of the Society of Naval Architects of Korea
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• v.59 no.2
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• pp.45-61
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• 2022

• Food Science of Animal Resources
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• v.36 no.1
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• pp.19-22
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• 2016

This study was conducted to improve sensory quality of Jokbal (Korean Pettitoes) made from frozen pig feet by addition of herbal mixture (glasswort, raspberry and Sansa powders). After adding herbal mixture, lipid oxidation (2-thiobarbituric acid values, TBARS), sensory property, and textural property were determined. Herbs were individually added into cooking soup at concentration of 6% (low concentration treatment, LCT) or 12% (high concentration treatment, HCT) of raw pig feet. Refrigerated pig feet were used as control. Thawed feet without any herbal mixture were used as freezing treatment (FT). TBARS in LCT or HCT were lower than that in FT, and showed the similar to that in Control. Addition of the herbal mixture was effective in improving the flavor and textural property of thawed feet by inhibiting lipid oxidation and protein denaturation in a dose-dependent manner.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.544-549
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• 2005

Web-based collaboration platforms present construction project teams with an opportunity to improve the efficiency of document exchange, better control project communications and enhance team collaboration. However, many construction professionals are still not convinced that these platforms, in their current form, are fit-for-purpose and yield sufficient efficiencies for the construction procurement process. In an attempt to improve the current ICT diffusion process, this paper evaluates the implementation of a web-based collaboration tool on the Lane Cove Tunnel (LCT) project in Sydney, Australia. Moreover, the paper provides strategies for achieving more effective implementation of web-based collaboration platforms in the construction sector.