• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.4
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• pp.374-382
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• 2009

Steam generator(SG) tube, as a barrier isolating primary to the secondary coolant system of nuclear power plants(NPP), must maintain the structural integrity far the public safety and its efficient power generation capacity. And SG tubes bearing defects must be timely detected and taken repair measures if needed. For the accomplishment of these objectives, SG tubes have been periodically examined by eddy current testing(ECT) on the basis of administrative notices and intensified SG management program(SGMP). Stress corrosion cracking(SCC) on the SG tubes is not easily detected and even missed since it has lower signal amplitude and other disturbing factors against its detection. However once SCC is developed, that can cause detrimental affects to the SG tubes due to its rapid propagation rate. Accordingly SCC is categorized as prime damage mechanism challenging the soundness of the SG tubes. In this study, reproduced EDM notch specimens are examined for the detectability and quantitative characterization of the axial ODSCC by +PT MRPC probe, containing pancake, +PT and shielded pancake coils apart in a single plane around the circumference. The results of this study are assumed to be applicable fur providing key information of engineering evaluation of SCC and improvement of confidence level of ECT on SG tubes.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.5
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• pp.466-471
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• 2011

Optical coherence tomography(OCT) is an emerging medical diagnostic tool that draws great attention in medical and biological fields. It has a 10-100 times higher spatial resolution than that of the clinical ultrasound but lower imaging depth such as 1-2 mm. In order to image internal organs, OCT needs an endoscopic probe. In this paper, the principle of Fourier-domain optical coherence tomography with high-speed imaging capability was introduced. An OCT endoscope based on MEMS technology was developed. It was attached to the Fourier-domain OCT system to acquire three-dimensional tomographic images of gastrointestinal tract of New Zealand white rabbit. The endoscope had a two-axis scanning mirror that was driven by electrostatic force. The mirror stirred an incident light to sweep two-dimensional plane by scanning. The outer diameter of the endoscope was 6 mm and the mirror diameter was 1.2 mm. A three-dimensional image rendered by 200 two-dimensional tomographs with $200{\times}500$ pixels was displayed within 3.5 seconds. The spatial resolution of the OCT system was 8 ${\mu}m$ in air.

• Journal of Veterinary Clinics
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• v.32 no.6
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• pp.481-485
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• 2015

The present study determined the normal reference ranges for overall pelvic limb alignment of small-breed dogs. For this purpose, 60 cadaveric canine pelvic limbs from normal small-breed dogs (Maltese, Poodle, Shih Tzu, Yorkshire Terrier). A frontal full-limb radiograph of each pelvic limb was obtained, and mechanical tibiofemoral angle (mTFA), mechanical metatarsotibial angle (mMTTA), mechanical axis-femur angle (MAFA), and mechanical axis-metatarsus angle (MAMTA) were measured from each radiograph, along with mechanical deviation of the stifle (SMAD) and tarsal joints (TMAD). The 95% CI for radiographic values of all pelvic limbs were mTFA, 5.7-7.4; mMTTA, $-2.2--0.8^{\circ}$; MAFA, $3.5-4.5^{\circ}$; MAMTA, 1.0-2.0; SMAD, 2.1-2.7%; TMAD, 0.5-1.0%. There values varied among the breeds, except for mTFA. The reference ranges can be used for diagnosing pelvic limb deformities in small-breed dogs and for planning corrective osteotomies.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.643-654
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• 2018

In order to understand and manage traffic flows in urban areas in the past, a variety of traffic engineering theoretical indicators such as intersection lag and highway speed have been applied. However, these theories and indicators have been developed under the constraints of traffic engineering research before the construction of intelligent transportation system. Since the ATIS system currently exists, it is necessary to introduce a separate traffic engineering technology that utilizes the data. In this paper, it is aimed to confirm whether it is applicable to intermittent flow (approach road, intersection, control group, main road axis) by using 'congestion intensity' which is already used in traffic engineering field. The results of this study are as follows: (1) The traffic signal improvement effect of urban road access road, intersection road, control group, Two verification studies were performed to verify the derived congestion intensity index. (1) verification of congestion intensity threshold value analysis and (2) crossing improvement using the congestion intensity. Through verification, it was confirmed that it is possible to apply the congestion intensity in the inter - city intermittent flow using the 5 - minute unit speed data so as to be able to escape from the existing traffic signal operation management which is past passive and manpower limit.

• The Journal of the Acoustical Society of Korea
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• v.21 no.8
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• pp.766-771
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• 2002

In this study, we have developed a 3-dimensional diagnostic ultrasonic sector probe using a convex type ultrasonic probe with 128 active elements. The probe was made to operate at the center frequency of 4.5㎒ with the bandwidth of 66%. The driving part was designed to rotate the axis of the convex probe by means of a step motor equipped with reduction gears and spur gears attached to the motor so that the probe could enable us to acquire a series of 2-dimensional images to construct a 3-dimensional image. Acoustic cover of the probe was made of polymers to have the same radius of rotation as that of the convex probe. The controllability of the rotation angle and the structural stability of the probe were confirmed through experimental 3-dimensional images obtained using the developed 3-dimensional sector probe.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.6
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• pp.113-119
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• 2016

In this study, the method to predict the lateral response by using strain data is presented on the steel moment frame. For this, the reliability of the proposed method by applying the example of five-story frame structure were verified. Using the strain value of columns, it predicted the lateral response of structure. It is assumed that all of four strain sensors for one column set up and the strain responses of both end of the column are utilized. The lateral response of member is calculated by using the slope deflection method. Also, using the acceleration response of the one layer, the stiffness of the rotation spring located in the supporting point is predicted. As a result, it was effective to understand the lateral displacement and acceleration responses and to predict local damage and location.

• Journal of KIISE:Software and Applications
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• v.30 no.9
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• pp.821-828
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• 2003

The virtual angioscopy was implemented using MR angiography image of carotid artery Inside of the carotid artery is one of the body region not accessible by real optical endoscopy but can be visualized with virtual endoscopy. In order to determine the navigation path, we segmented the common carotid artery and internal carotid artery from the MR angiography image. We used the coordinates as a navigation path for virtual camera that were calculated from medial axis transformation. We used the perspective projection and marching cube algorithm to render the surface from volumetric MRA image data. A stroke occurs when brain cells die because of decreased blood flow to the brain. The carotid artery is the primary blood vessel that supplies the blood flow to the brain. Therefore, the carotid artery stenosis is the primary reason of stroke. The virtual angioscopy is highly recommended as a diagnosis tool with which the specific Place of stenosis can be identified and the degree of stenosis can be measured qualitatively. Also, the virtual angioscopy can be used as an education and training tool for endoscopist and radiologist.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.131-131
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• 2003

2002년도 국내에서 실시된 가축의 수정란이식 현황을 파악하기 위하여 전국의 수의ㆍ축산분야의 대학, 국ㆍ공립 축산관련 연구소, 농업기술센터, 가축인공수정소 및 동물병원 등의 168개 관련기관에 2002년 1월 1일부터 12월 31일까지 소, 돼지 및 기타 동물의 수정란 생산, 이식 및 임신진단 결과에 대하여 설문서를 통하여 조사하였으며, 설문서를 작성하여 제출한 32개기관의 자료를 분석한 결과는 다음과 같다. 가축의 수정란이식을 실시하고 있는 기관은 국립기관 4개소, 지방자치단체 10개소, 대학 7개소, 생산자단체 3개소, 개인시술소 148개소로 전체 172개소였다. 한우 및 젖소 185두를 과배란처리하여 회수된 난자수는 1,334개였으며, 그 중 이식가능수정란수는 871개로 두당 평균 4.7개였다. 체외수정의 생산은 OPU유래 266개, 도축난소 유래 16,650개, 복제수정란 21,852개로 38,768개의 이식가능 체외수정란을 생산하였다. 한우에서 수정란이식은 체내수정란 475두, 체외수정란 7,515두, 복제수정란 257두 등 8,247 두가 이식되었고, 젖소에는 체내수정란 68두, 체외수정란 58두, 복제수정란 435두 등 294두가 이식되었다. 이식된 수정란의 상태별로는 신선수정란이 73.9% (6,511두), 동결수정란이 26.1%(2,297두) 이식되었고, 수란우의 품종별로는 한우 수정란을 한우 수란우에 690두, 젖소 수란우에 7,557두가 이식되었고, 젖소 수정란을 젖소 수란우 81두, 한우 수란우에 480두가 이식되었다. 수정란이식 수란우의 수태율은 임신진단이 이루어진 체내수정란이식은 33.8% (160/472두), 체외수정란이식은 34 7%(1,547/4,456두), 복제수정란이식은 10.5%(70/669두)였다. 소의 수정란이식두수는 2001년도에 비해 217%(8,808/4,052두)가 증가하였다. 돼지에서 체내수정란은 공란두 30두에서 505개의 이식가능수정란을 회수하였으며, 체외수정란은 351,777개를 생산하였고, 형질전환수정란을 수란돈 20두에 1,919개를 이식하였었다. 염소에서는 7두의 공란축으로부터 47개의 이식가능 수정란을 회수하였다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.6
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• pp.1-8
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• 2016

As demand for paper cups markedly increases, this has brought about a requirement to develop fast paper cup forming machines. However, the fast manufacturing speed of these machines causes faults to occur more frequently in the final product. To reduce the possibility of producing faulty products, it is necessary to develop technologies to monitor the manufacturing process and diagnose the machine status. In this research, we selected the main driving axis of the forming machine for fault diagnosis. We searched the states of rotational elements related to the driving axis and suggested a fault diagnostic system based on spectrum analysis consisting of a real-time data acquisition device, accelerometers, and a diagnosis algorithm. To evaluate the developed fault diagnostic system, we performed experiments using a test station which resembles the actual paper cup forming machine. As a result, we were able to confirm that the proposed system was sufficiently feasible to diagnose any abnormalities in the operation of the paper cup forming machine.

• Journal of Korean Society of Steel Construction
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• v.23 no.5
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• pp.629-636
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• 2011

This paper describes the smart structural system that uses smart materials for real-time monitoring and active control of bolted joints in steel structures. The impedance-based structural health monitoring (SHM) techniques, which utilize the electro-mechanical coupling property of piezoelectric materials, was used to detect loose bolts in bolted joints. By monitoring the measured electrical impedance and comparing it with the measured baseline, a bolt loosening damage was detected. The damage was evaluated quantitatively using the damage metrics in conductance signature with respect to the healthy states. When loosening damage was detected in the bolted joint, the external heater actuated the shape memory alloy (SMA) washer. Then the heated SMA washer expanded axially and adjusted the bolt tension to restore the lost torque. An experiment was conducted by integrating the piezoelectric-material-based SHM function and the SMA-based active control function on a bolted joint, after which the performance of thesmart self-healing joint system was investigated.