• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.1
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• pp.8-14
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• 2020

According to the statistics provided by Korean Maritime Safety Tribunal for the year 2018, the majority of marine accidents in the past four years have occurred in fishing boats and small-sized boats. Negligent behavior resulting from not looking outside and non-compliance with navigation laws are the primary reasons behind ship collisions. Although safety education and training are reinforced to prevent such accidents, they still occur frequently. Hence, technical methods are continuously being developed to reduce ship collisions caused by human cause. The objective of this study is to reduce ship collisions by employing the WAVE communication system, which has short transmitting and receiving periods that can be incorporated for high-speed small-sized vessels. In this study, the suitability of the communication range was examined, and the appropriate range and timing for avoidance motion were accordingly selected, and a control algorithm based on the same was thereby designed. Consequently normal operation of the collision avoidance system was verified by connecting and simulating the proposed WAVE communication router-controller-steering equipment.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.03a
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• pp.161-176
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• 2002

Collision avoidance is the most important part of a small vessel. Small and mediurn sized ships are surprisingly poor targets for radar reflection and are frequently in danger of being overrun by large vessels, even under good condition of visibility. One of the best way to prevent collisions at sea is to use as large and well designed a radar reflector. Thus, RCS(Radar Cross Section) increase is key element in the design of radar reflector. Radar Reflectors are normally classified into active-type and passive-type. In this paper, the RCS increase methods for passive-type reflector through shaping are explained, and analyzed with RCS performance test by computer simulation. As results from analysis, It is shown that the effective diameter of radar reflector is over 10 λ to provide a return above the threshold RCS of 25m$^2$, lower limit of detectability using X-band radar in a moderate sea.

• Nuclear Engineering and Technology
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• v.44 no.5
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• pp.501-506
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• 2012

Many innovative design features are employed in the reactor vessel internals of SMART, a small integral-type pressurized water reactor, one of which is the flow skirt, which uniformly distributes flow and horizontally restrains the lower part of the core support barrel. This new design requires a comprehensive investigation of vibration characteristics. Therefore, in this study, modal characteristics of flow skirts are investigated with finite element analysis. Specifically, we investigate how the presence of holes, the presence of three rings attached to the flow skirt, and the thickness of the lowest shell effect vibration characteristics. In addition, the fluid effect is addressed, since the flow skirt is submerged in the fluid.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.97-101
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• 2004

In this paper, we study the fishery detection system for protection of an aquamlture farm. The FDS(fishery detection system) will be recognize a robbing vessel with real time and variance the position of aquaculture farm. We try to develop the F-AIS(Fishery Automatic Identification System) which am be detect approaching object to aquaculture farm and distinguish our fishing boot from thief vessel. The F-AIS with low price and wideband responsibility am be adopt to the FDS, i. e. the identification for a small-sized fishing boots.

• Journal of Chest Surgery
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• v.9 no.1
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• pp.44-49
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• 1976

Aneurysm of the Aorta is a grave disease mostly producing disabling symptoms and ultimate death by rupture and hemorrhage without surgical intervention. The author recently experienced one case of surgical correction of descending thoracic aortic aneurysm treated with excision of the aneurysm and replacement of Dacron artificial vessel under temporary external by pass technique in November, 10th, 1975. 9mm internal diameter arterial cannula was inserted into upper and below the aneurysm. Bypass time was about 1 hour. The case was 35 years old women who had small egg sized saccular aneurysm in the upper third of the descending thoracic aorta involving the 1t. subclavian artery. Histopathological diagnosis was arteriosclerotic. Immediate postoperative course had been uneventful except low pressure and pulse of the left arm. The follow-up was possible up to date about 3 months. The patient has been doing well with ordinary activities except mild left chest discomfort.

• Nuclear Engineering and Technology
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• v.38 no.1
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• pp.33-44
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• 2006

This paper presents a review of small-to-medium-sized, pressurized-water-cooled nuclear power reactors whose major primary coolant systems are integrated into a reactor pressure vessel, the concepts categorized as Integrated Primary System Nuclear Reactors (IPSRs). Typical examples of these proposals of interest in this review are CAREM, SMART, IRIS and IMR, all of which are being aimed at the near term deployment. Emphasis is placed on thermal hydraulic aspects. A brief characterization of the IPSR concepts is made and comparisons of plant key parameters are shown. Discussions will follow for the core cooling under rated power conditions and natural circulation heat removal on the basis of the design data available in the public domain.

• Journal of Chest Surgery
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• v.17 no.4
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• pp.691-697
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• 1984

After the real birth of vascular surgery occurred with the introduction of the first practical arterial prosthesis about 50 years ago, a variety of potential vascular graft had been tested and rejected. Polytetrafluoroethylene [Teflon, PTFE] was first used as a vascular prosthesis in 1957. Thereafter this pros-thesis was first used clinically in 1972 and has subsequently been widely applied as a small and medium sized vessel replacement because it is easy to use and readily available. There are numerous reports of good results about Polytetrafluoroethylene graft. We experienced the three cases of arterial bypass graft using polytetrafluoroethylene vascular pros-thesis. First, 21 years old female patient had suffered from Takayasus disease which affected the left subclavian artery and right subclavian-left axillary extra anatomical bypass graft as done. Second, 64 years old male patient had suffered from Leriche syndrome for 12 years and the left axillofemoral and femorofemoral extra anatomical bypass graft was done. Third, 34 years old male patient had suffered from recurrent Buergers disease which affected the left popliteal artery and the isolated popliteal artery segment bypass graft was done. Relatively satisfactory result was obtained in early post-operative period in all three cases.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.1 s.28
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• pp.39-45
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• 2007

Recently it is a tendency that the heavy fuel oil is considered to be used on board even middle or small sized vessels in order to reduce the operating cost of vessel mused by a rise in international oil prices. In this study, analyzed the physical & chemical properties and examined the effect of refining treatment and a fuel oil additive for MF30 fuel oil which is a mixture fuel oil mixed M.G.O and the heavy oil MF380 use to be possible in the middle&small class vessel. As a results, the effects of two of pre-refinery treatment methods as centrifugal purifier and heating & homogenizing system(M.C.H) are some feeble, but the pour point and the flash point came to be low more or less. The effect of property improvement which is mused by the fuel oil additive did not appear positively.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.4
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• pp.56-61
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• 2009

This paper presents the ground surface potential profiles and hazard voltages around the metallic structure connected to a small-sized model ground electrode. Because it is very difficult to draw valid conclusions concerning a general grounding problem from actual field data, scale model tests can be used to determine the touch and stop voltages and surface potential profiles around ground electrode. In this work, a hemispherical vessel with a diameter of 1,100[mm] was employed to simulate uniform soil. As a result, the ground surface potential around the ground electrode was significantly raised In particular the ground surface potential at the just upper point of ground rod was higher than other points. When the buried depth of ground rod is increased, the ground surface potential and step voltage were lowered but the touch voltage was elevated.

• Archives of Reconstructive Microsurgery
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• v.14 no.1
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• pp.57-62
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• 2005

Microvascular anastomosis with suture technique is a basic skill but there are several problems such as stenosis, thrombosis and long operating time. Recently plastic surgeons have developed non-suturing mechanical coupling devices for microvascular anastomosis. The authors applied non-penetrating vascular clips (VCS clips) in the field of free flap surgery of head and neck area. Between August of 2004 and January of 2005, we performed 9 free flaps (16 vessels) using small-sized VCS clips. Four stay sutures were applied first and then VCS clips were placed between sutures about 1 mm apart. Vascular pedicle of free flap included the descending branch of lateral circumflex femoral vessel, thoracodorsal vessel, deep inferior epigastric vessel and cephalic vein. The recipient vessels were the superior thyroid artery, superficial temporal artery, internal jugular vein, external jugular vein, and superficial temporal vein. We performed 13 end-to-end (4 arteries and 9 veins) and 3 venous end-to-side anastomoses. No flap related complication occurred but we applied additional clips or sutures in two cases due to blood leakage after completion of anastomosis. Primary patency rates seemed to be good and more rapid anastomosis could be done than conventional suture technique. Advantages of VCS technique are high patency rate, low thrombogenecity and rapidity. Although the high cost of VCS instrument may be a problem, this clip could be applied safely in microvascular free tissue transfer.