• Special Issue of the Society of Naval Architects of Korea
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• 2008.09a
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• pp.46-53
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• 2008

Recently, the synthetic material stern tube bush has been applied by ship owner's requirement because the synthetic material has a merit. That is to say, when stern tube seal is damaged and sea water comes into stern tube, it can work without problem because of water lubricating property. However, the material also has a demerit of temperature rise problem when some factors meets on synthetic material, for example, not sufficient lubrication oil supply and not proper shaft alignment and so on. As known in the world, the RAILKO bush is rampant for synthetic material by some ship owner because of the above mentioned reason. However, the bush has several accidents on large container vessel. Unfortunately or fortunately our yard has a chance to apply the RAILKO bush owing to requirement of specific ship owner. Therefore, it is much more required to approach the accurate shaft alignment analysis. In line with this reason, we had a shaft alignment calculation considering hull deformation and hull flexibility (hull stiffness). Also, in the calculation, we had considered dynamic condition which is reflected he propeller thrust forces and moments and oil film stiffness on the shaft alignment calculation. According to he shaft alignment calculation, bearing slope was applied on the tern tube bush and was measured. The RAILKO bush should be applied the running in procedure according to maker's recommendation for performing the oil film on the bush surface. Finally, the vessels were delivered successfully without any problem with AILKO bush as shown on his paper.

• Journal of the Korean Wood Science and Technology
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• v.22 no.4
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• pp.26-36
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• 1994

The comparative wood anatomy of 1 species belonging to genus Myrica of Myricaceae, 9 species to genus Populus and 8 species to genus Salix of Salcaceae, occurring in Korea, was described and coded according to IAWA list(Wheeler, 1989). Myrica rubra. of Myricaceae is a typical diffuse-porous wood with numerous vessels per $mm^2$ and its pores are mainly angular in outline. Vessels scalariform perforation plates with a few bars, very small inter vessel pits; axial parenchyma abundant, diffuse or diffuse-in-aggregates which is distinct and easily observed on cross section; rays 1-3 seriate, Kribs' heterogeneous I or II types, frequently contains rhomboidal crystals; Dark pigmented substances included in some rays and axial parenchyma. Salicaceae, a typical diffuse porous wood, has mainly radial pore multiple, large intervessel pits, distinct alternate pits, simple perforation plates, ray-vessel pits with circular large pits, uniseriate rays, marginal parenchyma composed of 1-2 layers. In some species, ray parenchyma contain crystals. Populus and Salix wood can be distinguished from one another by the following characters. Pores of Populus woods almost angular in outline. Uniseriate homogeneous rays slightly higher than Salix and long linear on tangential section. Whereas Salix woods appear the pores almost oval, uniseriate heterogeneous rays, which are smular narrow fusiform on tangential section and lower in height than Populus.

• Plant Resources
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• v.3 no.3
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• pp.163-172
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• 2000

We compared microstructural features of the ordered cell and disordered leaves in Citrus junos Sieb. by electron microscopy. In the cell of the ordered leaves, many chloroplasts and large vacuoles were particularly observed. Also a lot of vessel, companion cell and big nucleus were presented in vascular bundle regions. The mitochondria and the other organelles were interspersed among the chloroplasts in a thin, peripheral layer of cytoplasm. The chloroplast possessed typical grana and intergranal lamellae, numerous starch grains and a few small osmophilic globules. Besides, microbodies were closely associated with the mitochondria and the chloroplast. The process of the formation of the secondary cell wall from primary cell wall was observed the vessel elements, the tonoplast wall and the secondary cell wall. It was observed that the oil sac with the unique perfume distributed the adjacent cell wall. In the cell of disordered leaves, the all of the organelles were thrust toward the cell wall due to the fusion of vacuoles in the cells. It was observed that a lot of the very small particles spreaded in the cytoplasm. The loss of unique perfume of the leaves was resulted in the destruction of the oil sac. Also, there was not observed grana, lamellae, starch and osmophillic globules in the chloroplast. The small distributed organelles was not observed but the elongation of the cell wall was proceed no longer. Therefore, the plasma membrane diverged from the cell wall. All of organelles in the cell had poor function and deformation. A massive vacuole was fulfilled in single cell and the vacuole contains a lot of large and small particles. The organelles were presented on the side of the cell wall according to the enlargement of vacuole and they were observed to be breakdown.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.228-229
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• 2018

To deal with the increasing volume of the vessel's cargo in the container flow and the enlargement trend of the vessels, Pusan port is making efforts from various perspectives such as the creation of global infrastructure and the promotion and development of new wharves. If Pusan port can provide and prepare the eligible infrastructures for future berthing of larger vessels. It will be able to operate with vessels larger than 20,000TEU, and it will also be able to grow into one of the main port of the Mega max era.. However, when large vessels dock, many berths, equipment, working time and labors are required. As a result, the problem of delaying time of other consecutive vessels will inevitably arise. In response to this, we analyze the impact and effect of the birthing of a large vessel on other congestion vessels at a container terminal.

• Korean Journal of Radiology
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• v.21 no.1
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• pp.101-107
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• 2020

Objective: Avoiding a catastrophic outcome may be a more realistic goal than achieving functional independence in the treatment of acute stroke in octogenarians. This study aimed to investigate predictors of catastrophic outcome in elderly patients after an endovascular thrombectomy with an acute anterior circulation large vessel occlusion (LVO). Materials and Methods: Data from 82 patients aged ≥ 80 years, who were treated with thrombectomy for acute anterior circulation LVO, were analyzed. The association between clinical/imaging variables and catastrophic outcomes was assessed. A catastrophic outcome was defined as a modified Rankin Scale score of 4-6 at 90 days. Results: Successful reperfusion was achieved in 61 patients (74.4%), while 47 patients (57.3%) had a catastrophic outcome. The 90-day mortality rate of the treated patients was 15.9% (13/82). The catastrophic outcome group had a significantly lower baseline diffusion-weighted imaging-Alberta stroke program early CT score (DWI-ASPECTS) (7 vs. 8, p = 0.014) and a longer procedure time (42 minutes vs. 29 minutes, p = 0.031) compared to the non-catastrophic outcome group. Successful reperfusion was significantly less frequent in the catastrophic outcome group (63.8% vs. 88.6%, p = 0.011) compared to the non-catastrophic outcome group. In a binary logistic regression analysis, DWI-ASPECTS (odds ratio [OR], 0.709; 95% confidence interval [CI], 0.524-0.960; p = 0.026) and successful reperfusion (OR, 0.242; 95% CI, 0.071-0.822; p = 0.023) were independent predictors of a catastrophic outcome. Conclusion: Baseline infarct size and reperfusion status were independently associated with a catastrophic outcome after endovascular thrombectomy in elderly patients aged ≥ 80 years with acute anterior circulation LVO.

• Journal of Korean Neurosurgical Society
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• v.67 no.1
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• pp.14-21
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• 2024

Objective : The primary treatment goal of current endovascular thrombectomy (EVT) for emergent large-vessel occlusion (ELVO) is complete recanalization after a single maneuver, referred to as the 'first-pass effect' (FPE). Hence, we aimed to identify the predictive factors of FPE and assess its effect on clinical outcomes in patients with ELVO of the anterior circulation. Methods : Among the 129 patients who participated, 110 eligible patients with proximal ELVO (intracranial internal carotid artery and proximal middle cerebral artery) who achieved successful recanalization after EVT were retrospectively reviewed. A comparative analysis between patients who achieved FPE and all others (defined as a non-FPE group) was performed regarding baseline characteristics, clinical variables, and clinical outcomes. Multivariate logistic regression analyses were subsequently conducted for potential predictive factors with p<0.10 in the univariate analysis to determine the independent predictive factors of FPE. Results : FPE was achieved in 31 of the 110 patients (28.2%). The FPE group had a significantly higher level of functional independence at 90 days than did the non-FPE group (80.6% vs. 50.6%, p=0.002). Pretreatment intravenous thrombolysis (IVT) (odds ratio [OR], 3.179; 95% confidence interval [CI], 1.025-9.861; p=0.045), door-to-puncture (DTP) interval (OR, 0.959; 95% CI, 0.932-0.987; p=0.004), and the use of balloon guiding catheter (BGC) (OR, 3.591; 95% CI, 1.231-10.469; p=0.019) were independent predictive factors of FPE. Conclusion : In conclusion, pretreatment IVT, use of BGC, and a shorter DTP interval were positively associated with FPE, increasing the chance of acquiring better clinical outcomes.

• Journal of Fisheries and Marine Sciences Education
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• v.21 no.1
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• pp.52-58
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• 2009

With the increase of marine traffic capacity, marine accidents have also been increased for recent several years. Especially watch officer must maneuver not entering into the safety minimum approaching distances when two power-driven vessels are crossing. The author calculated the safety minimum approaching distances to provide a navigator with them based on zig-zag motion by experimental ship. The obtained results are summarized as follows : 1. The greatest distance is to be kept by the give way vessel to avoid collision when the crossing course angle is $90^{\circ}$. In this case the safety minimum approaching distance must be more than from 5 times to 11 times of her own length according to her size. 2. The watch officer of the give way vessel must always take an action to avoid collisions outside of the safety minimum approaching distance. 3. When the navigator used rudder to small angle than to large angle to avoid other vessel he must take action outside the sufficient safety minimum outside distances in advance. 4. Risk of collision in crossing situation is more greater in obtuse situation than in acute one.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.2
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• pp.196-204
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• 2016

World Health Organization reported that heart-related diseases such as coronary artery stenoses show the highest occurrence rate which may cause heart attack. Using Computed Tomography angiography images will allow radiologists to detect and have intervention by creating 3D roadmapping of the vessels. However, it is often complex and difficult do reconstruct 3D vessel which causes very large amount of time and previous researches were studied to segment vessels more accurate automatically. Therefore, in this paper, Region Competition, Geodesic Active Contour (GAC), Multi-atlas based segmentation and Active Shape Model algorithms were applied to segment aortic root from CTA images and the results were analyzed by using mean Hausdorff distance, volume to volume measure, computational time, user-interaction and coronary ostium detection rate. As a result, Extracted 3D aortic model using GAC showed the highest accuracy but also showed highest user-interaction results. Therefore, it is important to improve automatic segmentation algorithm in future

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.4
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• pp.397-402
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• 2013

In this study, numerical hull form development of a platform supply vessel, a full scale with the overall length of 26.75m, was performed to predict a bare-hull resistance and a large scale of model tests with a 1/10 scaled model were conducted to verify the success of numerical results. Numerical analysis on heave and pitch motion as a function of encounter frequency and ship's speed for the prediction of seakeeping characteristics are also presented. The experiment results of resistance agreed well with numerical analysis. As a result in the motion response characteristics, the heave RAO indicates high values with the range of encounter frequency 1.8~2.0. The Pitch RAO indicates high motion response characteristics at Beaufort scale No. 3 and 4 in rough seas.

• Journal of the Korean Society for Heat Treatment
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• v.29 no.1
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• pp.15-23
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• 2016

The effects of austenitizing temperature and cooling rate on precipitation behavior and tensile properties were investigated in an Mn-Mo-Nb-V pressure vessel steel. During austenitizing, it was shown that the austenite coarsening was somewhat suppressed by undissolved NbC. After cooling from austenitizing, the microstructure of all the steels mainly consisted of upper bainite. However, the steel comprised a little lower bainite and martensite in the case of aqua oil quenching from $1000^{\circ}C$, which would be due to increased hardenability by partly dissolved Nb and comparatively large austenite grains. The average size of NbC in austenite at higher temperature was analyzed to be smaller than that at lower temperature because of the more dissolution. It was found that the NbC did not grow much during fast cooling from austenitizing. Meanwhile, the NbC grew much during slow cooling, probably due to wide temperature range of cooling and sufficiently long time for NbC to grow. It was conjectured the V precipitates newly formed and/or grew during cooling from austenitizing and during tempering. On the other hand, the formation of NbC was almost completed before tempering and little more precipitated during tempering. Among the tempered steels, the steel which was fast cooled from $1000^{\circ}C$ showed the highest tensile strength, which seemed to come from the microstructure of fine upper bainite and some low temperature phases as well as the comparatively fine NbC precipitates.