• Journal of the Society of Naval Architects of Korea
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• v.42 no.5 s.143
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• pp.479-486
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• 2005

The final goal of shift alignment design is that the bearing reaction forces or mean pressures are within design boundaries for various service conditions of a ship. However, it is found that calculated bearing load can be substantially variable according to the locations of the effective support points of after sterntube bearing which are determined by simple calculation or assumption suggested by classification societies. A new analysis method for shaft alignment calculation is introduced in order to resolve these problems. Key concept of the new method is featured by adopting both nonlinear elastic and multi-support elements to simulate a bearing support Hertz contact theory is basically applied for nonlinear elastic stiffness calculation instead of the projected area method suggested by most of classification societies. Three loading conditions according to the bearing offset and the hydrodynamic moment and twelve models according to the locations of the effective support points of sterntube bearings are prepared to carry out quantitative verifications for an actual shafting system of 8000 TEU class container vessel. It is found that there is relatively large difference between assumed and calculated effective support points.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.4
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• pp.772-778
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• 2011

In order to estimate the densities and composition of floating marine debris (FMD), a sighting survey was conducted from July 1st to July 14th, 2009 in the East China Sea (ECS) using a training vessel "Kaya (1,737 ton)" of Pukyong National University. The sampled zones are divided into 5 transects by observation day during the survey days and the densities and composition in each transect were calculated using the numbers of item per $km^2$. The results of distribution of FMD are as follows: 1. During the surveys, a large variety of FMD was discovered and highest densities were found in the Central East(CE) of the East China Sea(ECS) (48.2 items/$km^2$), whereas densities in the less populated transects in Okinawa(OK1, OK2) were comparatively low(3.5 ~ 4.9 items//$km^2$). 2. Among the classified 6 items, styrofoams(Styro) were most abundant and ubiquitous(10.3 items/$km^2$, 53% of the total number), except OK2 area. Next abundant item was vinyl and plastics called V & P(4.9 items/$km^2$, 25%). Above 2 items of the major proportion of FMD accounted for 78% of the total number of FMD observed through this study. 3. The percentages of manufactured plastics(Styro and V & P) found in the Seas near Korean Peninsula were varied from 87.2% to 69.8%. It was recognized that polluted level is middle value among them.

• Journal of Ocean Engineering and Technology
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• v.33 no.4
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• pp.313-321
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• 2019

The prediction of the hydrodynamic performance of a planing hull vessel is an important and challenging topic for computational fluid dynamic (CFD) applications to naval hydrodynamics. In this paper, the resistance and planing attitude analysis for a Fridsma hull, which is a prismatic planing hull, in still water are numerically studied using OpenFOAM. OpenFOAM is an open source code package based on C++ libraries and the finite volume method (FVM) for the discretization of the RANS equation. The volume of fluid method (VOF) is used to capture the water-air interface and the SST ${\kappa}-{\omega}$ model is used for the turbulence simulation. The overset mesh method is used to capture the large motion of the hull at higher speeds. Before the extensive analysis, uncertainty analyses using various time steps and grid sizes were performed for one ship speed case of Fn = 1.19. The results of the present study are compared with those of a model test, other CFD research, and Savitsky's empirical formula. The results of the present study, following the trend of other CFD results, slightly over predict the resistance and under predict the sinkage and, more significantly, the trim.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.1
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• pp.74-81
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• 2019

According to the recent presentation by the Korean Maritime Safety Tribunal, about 70% of marine accident occurs from fishing vessel, and 90% of cause of entire marine accidents attributes to human error. As fishing vessels require basic operations, fishing operations, other additional operations and techniques such as fish handling, cultivating excellent marine officer to prevent marine accident and develop industry is very important. A fisheries training ship is still very difficult to satisfy the demand for diversity of fishery training and sense of realism of the industry. As the result of employment expectation by category of business survey targeting 266 marine industry high school graduates who hope to board fishing vessels for the last four years, tuna purse seine was the highest with 132 cadets (49.6%), followed by offshore large purse seine (65 cadets, 22.4%), and tuna long line (35 cadets, 13.2%). The Korea Institute of Maritime and Fisheries Technology (KIMFT) has replaced old jigging and fish pot fishery training ships and proceeded developing and building multi-purpose fisheries training ships considering the demand of industry and the promotion of employment; however, the basic fishing method was set for a tuna purse seine. As a result of seakeeping model test, it can conduct the satisfiable operation at sea state 5, and survive at sea state 8.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.6
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• pp.881-889
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• 2022

As interest in environmental pollution caused by ship emissions is increasing worldwide, many studies are being conducted on the development of systems that increase energy efficiency to reduce ship emissions. In order to test the energy management system controller driven in real time on a large ship, it is necessary to perform the test through the simulator. In this study, addresses were set for each signal according to Modbus TCP/IP so that each control system and energy management system could be linked, and the algorithm was configured according to the signal flow. In addition, the signal generator was designed and manufactured so that each controller could artificially generate the signal collected from the vessel. As a result of the simulator production and interlocking, it was confirmed that each controller operated in real time performed its role appropriately, and that the algorithm of the ship energy management system was properly applied.

• Archives of Plastic Surgery
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• v.49 no.5
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• pp.683-688
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• 2022

Background Reconstruction of large soft tissue defects of the lower extremity often requires the use of free flaps. The main limiting factor and potential for complications lie in the selection of proper donor and recipient vessels for microvascular anastomosis. While the superficial veins of the lower leg are easier to dissect, they are thought to be more vulnerable to trauma and lead to a higher complication rate when using them instead of the deep accompanying veins as recipient vessels. No clear evidence exists that proves this concept. Methods We retrospectively studied the outcomes of 97 patients who underwent free flap plasty to reconstruct predominantly traumatic defects of the lower extremity at our institute. The most used flap was the gracilis muscle flap. We divided the population into three groups based on the recipient veins that were used for microvascular anastomosis and compared their outcomes. The primary outcome was the major complication rate. Results Overall flap survivability was 93.81%. The complication rates were not higher when using the great saphenous vein as a recipient vessel when comparing to utilizing the deep concomitant veins alone or the great saphenous vein in combination to the concomitant veins. Conclusions In free flap surgery of the lower extremity, the selection of the recipient veins should not be restricted to the deep accompanying veins of the main vessels. The superficial veins, especially the great saphenous vein, offer an underrated option when performing free flap reconstruction.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.3
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• pp.261-263
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• 2023

Recently, universities of fisheries and institutions related to fisheries are actively carrying out a project to build new fisheries training ships. These new fisheries training ships are significantly larger in size and longer in length than the previous ships. In addition, these new ships basically have space that can accommodate more than 100 crew and passenger. On the other hand, they are excluded from IMO maneuverability evaluation since the size of these ships are still less than 100 m in length (LBP). These results have had an impact on the study of maneuverability of fishing vessels including the fisheries training ships. Against these backgrounds, the authors conducted a study to estimate the maneuvering characteristics of fisheries training ship Baek-Kyung according to depth in order to prepare a maneuvering characteristic index that enables the large fisheries training ships to navigate more safely using a modified empirical formula. It was confirmed that the maneuvering characteristics of Baek-Kyung changed significantly as the values of the hydrodynamic force coefficients changed as the water depth gradually decreased from around 1.5 (approx. 8 m in depth) of the ratio of the water depth to the ship draft. The results of this study will not only help navigators understand the maneuvering characteristics of Baek-Kyung, but also serve as an indicator when navigating in shallow water. In addition, the accumulation of these results will serve as a basis for future study on maneuverability of fishing vessel types.

• The Journal of Korean Medicine
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• v.43 no.4
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• pp.131-144
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• 2022

Objectives: This study aimed to review clinical studies on thread embedding acupuncture (TEA) for the treatment of patients with post-stroke spasticity (PSS) Methods: Clinical studies related to TEA treatment for PSS were searched for in several electronic databases, including PubMed, Cochrane Library, MEDLINE, OASIS, and CNKI. After the selection/exclusion process, information on study design, disease, experimental/control group, intervention, outcome measurement, between-group differences, and adverse events was extracted. Results: A total of 13 randomized controlled trials were included in this review. The usual frequency of TEA treatment was once every 1-2 weeks, and the treatment most commonly included 4 sessions. In the dorsal area, EX-B2 and the acupoints in governing vessel meridian were commonly used. Acupoints in the meridian of the large intestine were most frequently used in the treatment of upper limb spasticity. Except for HT1, PC6, and PC8, all TEA points for treating PSS of the upper limb were on the Yang meridians. For the lower limb spasticity, the most frequently used acupoints were ST36, GB34, GB30, BL60, and BL57 on Yang meridians, and LR3, SP6, SP9, and SP10 on Yin meridians. TEA treatment showed better effects than conventional treatment for PSS in terms of spasticity, motor dysfunction, and activities of daily livings. Nevertheless, the absence of the follow-up observation, lack of sham TEA treatment, and low quality of the included studies necessitated caution in interpreting the results. Conclusions: The results of this review are expected to provide basic data on the modalities of TEA treatment for PSS and provide insights to facilitate well-designed studies in the future.

• The Journal of the Society of Stroke on Korean Medicine
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• v.7 no.1
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• pp.54-58
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• 2006

Objectives : This study was aimed to investigated the relationship between warning signs and stroke subtype in acute stroke patients. Methods : From Oct. in 2005 to Oct. in 2006, 409 acute stroke patients were included. Patients were hospitalized within 14 days after the onset of stroke in DongGuk University International Hospital, Kyungwon University In-cheon Oriental Medical Hospital, Department Cardiovascular and Neurologic Diseases(Stroke center) Kyung Hee University Oriental hospital. We investigated general characteristics, stroke subtype, and warning signs(facial spasm, neck stiffness). Results : Hemorrhagic stroke had more facial spasm than ischemic stroke. (odds ratio 3.60) Small vessel occlusion had more neck stiffness than others. (odds ratio 2.03) Conclusion : To acquire more concrete conclusions on warning signs, we need further and large scale of prospective researches.

• Korean Journal of Materials Research
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• v.33 no.7
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• pp.302-308
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• 2023

The influence of specimen geometry and notch on the hydrogen embrittlement of an SA372 steel for pressure vessels was investigated in this study. A slow strain-rate tensile (SSRT) test after the electrochemical hydrogen charging method was conducted on four types of tensile specimens with different directions, shapes (plate, round), and notches. The plate-type specimen showed a significant decrease in hydrogen embrittlement resistance owing to its large surface-to-volume ratio, compared to the round-type specimen. It is well established that most of the hydrogen distributes over the specimen surface when it is electrochemically charged. For the round-type specimens, the notched specimen showed increased hydrogen susceptibility compared with the unnotched one. A notch causes stress concentration and thus generates lots of dislocations in the locally deformed regions during the SSRT test. The solute hydrogen weakens the interactions between these dislocations by promoting the shielding effect of stress fields, which is called hydrogen-enhanced localized plasticity mechanisms. These results provide crucial insights into the relationship between specimen geometry and hydrogen embrittlement resistance.