• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.3
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• pp.225-232
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• 2017

Several maintenance issues related to cavitation erosion and fatigue cracks in the water turbine subcomponents of pumped-storage plants, such as a runner and a draft tube, have been reported in the past. Generally, the pumped-storage plants provide ancillary services, such as black-start and system stabilization. The ancillary services are responsible for cyclic low opening operation of the guide vanes. It has been empirically established that this low opening operation further damages the water turbine subcomponents. In this study, the acceleration effect of the low opening operation on the cavitation erosion and fatigue of the water turbine is quantitatively assessed through finite element flow analysis, finite element stress analysis, and fatigue analysis. As a result of the assessment, it is identified that the cavitation potential increases and the turbine efficiency decreases with a decrease in the opening of the guide vane. Also, the low opening operation has an insignificant effect on the fatigue even though it increases the maximum stress values at the runner blade roots.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1267-1274
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• 2012

A guide vane plays a key role in controlling the flow rate of water supplied to the turbine of a hydropower plant. It has been reported that guide vane bearing bushings are subjected to considerable wear, which requires them to be maintained. An ancillary service such as frequency control and black start causes cyclic low opening operation of the guide vanes. It is empirically well known that such operation increases the wear rate of the guide vane bearing bushing. In this study, the effect of low opening operation on the increasing wear of the guide vane bearing bushing is quantitatively assessed via finite element flow analysis, finite element stress analysis, and relative wear evaluation. As a result of the assessment, it is identified that the pressure applied on the guide vane surface increases and the contact length between the outer surface of the guide vane stem and the inner surface of the bearing bushing decreases with a decrease in the opening of the guide vane. In addition, low opening of the guide vanes results in an increase in the relative wear owing to the generation of high contact pressure on the bearing bushing surfaces.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.1
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• pp.73-80
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• 2015

The valve device is installed in hazardous areas, such as a chemical plant explosion has been sealed with fire protection device to prevent the risk of explosion. In this paper, due to the explosion-proof devices using external power the device can not be used in infrared sensors and Zigbee sensor valve device by measuring the open degree of valve opening and closing of the danger zone to check whether. Valve opening and closing operation log screen time, we propose a low-power operation monitoring system administrators to manage and control the plant. Develop power control relay board apply an improved algorithm to apply the asynchronous LPL power management. The plant monitoring system and explosion-proof valve opening and closing the valve system with the intelligent device designed and implemented and tested it.

• International journal of advanced smart convergence
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• v.9 no.1
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• pp.154-162
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• 2020

We studies show that ratio of corpse among cremated bodies in public cremation facilities in metropolitan cities using E-Haneul funeral information system is average 90.1%, which is high, in bigger metropolitan cities with over 2 million of population (Incheon, Busan, and Daegu), but is average 81.4%, which is relatively low, in smaller metropolitan cities with less than 2 million of population(Daejeon, Gwangju, and Ulsan). In addition, the cremated bodies ratio of opening remains is average 17.4% in smaller metropolitan cities with less than 2 million of population, but is average 8.9% in those with over 2 million of population, which is relatively low. Finally, the cremated bodies ratio of dead fetuses is average 1.2% in smaller metropolitan cities with less than 2 million of population, and average 1.0% in those with over 2 million of population, which is low. Based on the above result, we are the following suggestions to improve the effectiveness of funeral facility use by the increase of demand for public cremation facilities in metropolitan cities. First, Busan and Daegu, where the shortage of supply is expected due to the increase of demand for cremation of corpse, need to implement supply expansion policy of public cremation facilities to build or expand cremation furnaces. Second, Daejeon, Gwangju, and Ulsan, where the cremated bodies ratio of corpse is low, need to expand supply through expanded operation from existing 4~8 cremation numbers of public cremation facilities to 11 cremation numbers, which is the level of Seoul Metropolitan City. Third, there should be cremation furnaces exclusively for opening remains to prepare the increase of demand for opening remains in the years with leap month.

• The Korean Journal of Pain
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• v.26 no.4
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• pp.392-395
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• 2013

Epiduroscopy is very useful in the treatment of not only low back pain caused by failed back surgery syndrome, epidural scar or herniated disc but also by chronic refractory low back pain which does not respond to interventional conservative treatment including fluoroscopically-directed epidural steroid injections and percutaneous adhesiolysis. Because cauterization using a laser fiber has become recently available, a wider opening is required to enter into the sacral canal in the case of epiduroscopic laser neural decompression (ELND). However, in a few patients, it is difficult to insert a device into the epidural space due to stenosis around the opening, and there is no alternative method. Herein, we report a case where a hiatus rasp specially designed for such patients was used to perform the operation.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.9
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• pp.78-84
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• 2022

An air circuit breaker (ACB) is an electrical protection device that interrupts abnormal fault currents that result from overloads or short circuits in a low-voltage power distribution line. The ACB consists of a main circuit part for current flow, mechanism part for the opening and closing operation of movable conductors, and arc-extinguishing part for arc extinction during the breaking operation. The driving mechanism of the ACB is a spring energy charging type. The faster the contact opening speed of the movable conductors during the opening process, the better the breaking performance. However, there is a disadvantage that the durability of mechanism decreases in inverse proportion to the use of a spring capable of accumulating high energy to configure the breaking speed faster. Therefore, to simultaneously satisfy the breaking performance and mechanical endurance of the ACB, its driving mechanism must be optimized. In this study, a dynamic model of the ACB was developed using the MDO(Mechanism Dynamics Option) module of CREO, which is widely used in multibody dynamics analysis. To improve the opening velocity, the Taguchi design method was applied to optimize the design parameters of an ACB with many linkages. In addition, to evaluate the improvement in the operating characteristics, the simulation and experimental results were compared with the MDO model and improved prototype sample, respectively.

• Journal of Chest Surgery
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• v.13 no.2
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• pp.130-133
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• 1980

Since the first report of an operation for prolapsed intervertebral disk by Mixter and Barr[1934], many thousands of operations have been successfully performed without incident. Linton and White in 1945 reported the vascular complication, but perforation of large vessels is rare complication of operation for prolapsed disk. A medical student, aged 22 years, was performed to a disk operation [L4-5, Rt. on May 1977.] From postoperative 10th day, palpitation, generalized edema and substernal pain were noted, and 2 months later, wide pulse pressure [70-80 mmHg], continuous bruit and thrill on the Rt. low abdomen were followed. Aortography revealed arteriovenous fistula between just proximal to abdominal aortic bifurcation and inferior vena cava. So, fistulectomy [Resection of proximal 2 cm of C.I.A., Rt, including fistula opening and end to end anastomosis] was performed on July, 77. During follow up study, remained fistula between Rt. internal lilac artery and lilac vein was found 2 months later. Re-operation [Double ligation of the Rt. internal lilac artery] was don on January 1978. Postop. results were excellent, except impossible to ejaculation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.3
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• pp.445-451
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• 2016

General fuse elements of solution for fast acting operation characteristics made using silver or silver alloy, those are not able to dominate cost competition to the advanced global leaders that have not only high technology but competitive price. In this study, the method that compose the fuse elements manufactured solution of fast acting operation characteristics by using precision multi-layer thin film plating and helical cutting process from low-priced copper metal. Furthermore, in order to move rated current line of fuse due to the heat loses, the manufacture construction method of fixed resistor is introduced, and then Ni-P plating layer and Sn plating layer are introduced multiply for controling fine opening time characteristics. So this study can establish the high productive and low-priced production method.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.233-239
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• 1979

Ventricular septal defect associated with patent ductus arteriosus is well known cardiac anomaly that can be treated successfully by operation. This anomaly is found at low frequency. Seven cases of the combined malformation were operated on during the period from 1959 to 1978 in the Department of Thoracic Surgery, Seoul National University Hospital. Right heart catheterization and retrograde aortogram can diagnose the disease correctly. Staged operation in one case and one-stage operation in 5 patients were done. In all cases of the open heart surgery the closure of the ductus was done by transpulmonary suture of the PDA opening. Among 6 patients of the open heart surgery 2 operative death [33.3%] and one late death [total 50%] were noted. Four type II and one type I and one Type IV VSDs were found. In one case the anomaly was accompanied with aortic insufficiency by herniation of the right coronary cusp through Type I VSD.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.477-480
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• 2005

In this paper, we propose a preprocess method to needs for Car License Plate Recognition on poor environment. This preprocess method use multi images to get low value to compare images value. Last method was Opening operation that Using Edge pixel to add and subtraction. The Result was removed White pixel and very mini feather. But This method needs many process times and License Plate Recognition is low quality problem. Another method is median filter and conversion. This paper key idea that rain & snow is high value. So This paper propose get low value to compare image value.