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DEVELOPMENT OF AN AMPHIBIOUS ROBOT FOR VISUAL INSPECTION OF APR1400 NPP IRWST STRAINER ASSEMBLY

  • Jang, You Hyun;Kim, Jong Seog
    • Nuclear Engineering and Technology
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    • v.46 no.3
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    • pp.439-446
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    • 2014
  • An amphibious inspection robot system (hereafter AIROS) is being developed to visually inspect the in-containment refueling storage water tank (hereafter IRWST) strainer in APR1400 instead of a human diver. Four IRWST strainers are located in the IRWST, which is filled with boric acid water. Each strainer has 108 sub-assembly strainer fin modules that should be inspected with the VT-3 method according to Reg. guide 1.82 and the operation manual. AIROS has 6 thrusters for submarine voyage and 4 legs for walking on the top of the strainer. An inverse kinematic algorithm was implemented in the robot controller for exact walking on the top of the IRWST strainer. The IRWST strainer has several top cross braces that are extruded on the top of the strainer, which can be obstacles of walking on the strainer, to maintain the frame of the strainer. Therefore, a robot leg should arrive at the position beside the top cross brace. For this reason, we used an image processing technique to find the top cross brace in the sole camera image. The sole camera image is processed to find the existence of the top cross brace using the cross edge detection algorithm in real time. A 5-DOF robot arm that has multiple camera modules for simultaneous inspection of both sides can penetrate narrow gaps. For intuitive presentation of inspection results and for management of inspection data, inspection images are stored in the control PC with camera angles and positions to synthesize and merge the images. The synthesized images are then mapped in a 3D CAD model of the IRWST strainer with the location information. An IRWST strainer mock-up was fabricated to teach the robot arm scanning and gaiting. It is important to arrive at the designated position for inserting the robot arm into all of the gaps. Exact position control without anchor under the water is not easy. Therefore, we designed the multi leg robot for the role of anchoring and positioning. Quadruped robot design of installing sole cameras was a new approach for the exact and stable position control on the IRWST strainer, unlike a traditional robot for underwater facility inspection. The developed robot will be practically used to enhance the efficiency and reliability of the inspection of nuclear power plant components.

A Study on the Difference of Inspection on Sanhupung(産後風) (산후풍 인식 차이 조사)

  • Lee, Chang-Hoon;Cho, Jung-Hoon;Jang, Jun-Bock;Lee, Kyung-Sub;Byun, Sang-Hyun
    • The Journal of Korean Obstetrics and Gynecology
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    • v.19 no.4
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    • pp.148-158
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    • 2006
  • Purpose : Sanhupung(産後風) is not completed golden standards of diagnosis therefore doctors diagnose through symptoms and signs of patients in clinic same as progress of treatments. We polled oriental gynecologic specialists and non-specialisst to find out cognitive differences on Sanhupung. Subjects : We surveyed 83 specialists and 87 non-speciailist from May 15 2005 to Oct 15. We analyzed the result of respondants, 39 (47%) specialists and 65 (75%) nono-specialits). Methods : We sorted all symptoms in previous studies then we categorized them into 4 fields. The results are analyzed by frequency, importance and impact(frequency percentage${\times}$average importance). Results : Except back pain, all pain symptoms were lower evaluated in non-specialist on frequency. Except inguinal region pain, pain of lower limbs and back pain, all pain symptoms were lower evaluated in non-specialist on importance. Except the numbness of limbs, all items of whole body were lower evaluated in non-specialist on frequency. Except edema, numbness of hand and foot and discharge from the uterus, all items were lower evaluated in non-specialist on importance. All items of neuropsychotic symptoms were lower evaluated in non-specialist on frequency and importance.

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Minimizing Security Hole and Improving Performance in Stateful Inspection for TCP Connections (TCP연결의 스테이트풀 인스펙션에 있어서의 보안 약점 최소화 및 성능 향상 방법)

  • Kim, Hyo-Gon;Kang, In-Hye
    • Journal of KIISE:Information Networking
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    • v.32 no.4
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    • pp.443-451
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    • 2005
  • Stateful inspection devices must maintain flow information. These devices create the flow information also for network attack packets, and it can fatally inflate the dynamic memory allocation on stateful inspection devices under network attacks. The memory inflation leads to memory overflow and subsequent performance degradation. In this paper, we present a guideline to set the flow entry timeout for a stateful inspection device to remove harmful embryonic entries created by network attacks. Considering Transmission Control Protocol (TCP) if utilized by most of these attacks as well as legitimate traffic, we propose a parsimonious memory management guideline based on the design of the TCP and the analysis of real-life Internet traces. In particular, we demonstrate that for all practical purposes one should not reserve memory for an embryonic TCP connection with more than (R+T) seconds of inactivity where R=0, 3, 9 and $1\leqq{T}\leqq{2}$ depending on the load level.

Manufacturing of molybdenum pin(CCFL) for electrode - convergency research on design and manufacturing of JIG and Fixture for molybdenum pin manufacturing and inspection (전극용 몰리브덴 핀 제조-몰리브덴 핀 제작 및 검사용 JIG and Fixture 설계 및 제작 융합연구)

  • Lee, Jeong-Ick
    • Journal of the Korea Convergence Society
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    • v.11 no.6
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    • pp.197-201
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    • 2020
  • The molybdenum cup and molybdenum pin, which are the main materials of the molybdenum electrode used for the LCD BLU CCFL electrode, did not been developed in Japan and all of them are imported and used from Japan, is giving a competitive burden. In this research, to develop the manufacturing technology of molybdenum pin used for CCFL electrode of LCD BLU, development of linear processing technology, development of molybdenum wire surface treatment technology, development of wire cutting technology, production of molybdenum pin, design and fabrication of JIG and Fixture for inspection, molybdenum pin prototyping and analysis, and development of 100% molybdenum pin inspection technology. In this paper, especially, research on design and manufacturing of JIG and Fixture for molybdenum pin manufacturing and inspection is treated.

Development of rotational pulse-echo ultrasonic propagation imaging system capable of inspecting cylindrical specimens

  • Ahmed, Hasan;Lee, Young-Jun;Lee, Jung-Ryul
    • Smart Structures and Systems
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    • v.26 no.5
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    • pp.657-666
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    • 2020
  • A rotational pulse-echo ultrasonic propagation imager that can inspect cylindrical specimens for material nondestructive evaluations is proposed herein. In this system, a laser-generated ultrasonic bulk wave is used for inspection, which enables a clear visualization of subsurface defects with a precise reproduction of the damage shape and size. The ultrasonic waves are generated by a Q-switched laser that impinges on the outer surface of the specimen walls. The generated waves travel through the walls and their echo is detected by a Laser Doppler Vibrometer (LDV) at the same point. To obtain the optimal Signal-to-Noise Ratio (SNR) of the measured signal, the LDV requires the sensed surface to be at a right angle to the laser beam and at a predefined constant standoff distance from the laser head. For flat specimens, these constraints can be easily satisfied by performing a raster scan using a dual-axis linear stage. However, this arrangement cannot be used for cylindrical specimens owing to their curved nature. To inspect the cylindrical specimens, a circular scan technology is newly proposed for pulse-echo laser ultrasound. A rotational stage is coupled with a single-axis linear stage to inspect the desired area of the specimen. This system arrangement ensures that the standoff distance and beam incidence angle are maintained while the cylindrical specimen is being inspected. This enables the inspection of a curved specimen while maintaining the optimal SNR. The measurement result is displayed in parallel with the on-going inspection. The inspection data used in scanning are mapped from rotational coordinates to linear coordinates for visualization and post-processing of results. A graphical user interface software is implemented in C++ using a QT framework and controls all the individual blocks of the system and implements the necessary image processing, scan calculations, data acquisition, signal processing and result visualization.

Suggestion of the Domestic CCTV Inspection Sewer Pipe Defect Codeby Sewer Defect Frequency Analysis (국내 하수관로 결함빈도 분석을 통한 CCTV 조사 결함항목 코드 제안)

  • Son, Jooyoung;Lee, Jaehyun;Kim, Jungryul;Oh, Jeill;Yoon, Sungsoo
    • Journal of Korean Society of Water and Wastewater
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    • v.30 no.6
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    • pp.623-634
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    • 2016
  • Sewer condition assessment involves the determination of defective points and status of aged sewers by a CCTV inspection according to the standard manual. Therefore, it is important to establish a reliable and effective standard manual for identifying the sewer defect. In this study, analytic reviews of the CCTV inspection manuals of the UK, New Zealand, Canada and South Korea were performed in order to compare the defect codes and the protocols of condition assessment. Through this, we also established the standardized method for defect code and revised the calculation method of assigning the condition grade. Analyses of the types and frequencies of sewer defects that obtained by CCTV inspection of 7000 case results, showed that the joint defect and lateral defect were the most frequent defects that occurred in Korea. Some defect codes are found to be modified because those did not occur at all. This study includes a proposed new sewer defect codes based on sewer characteristics.

Real-Time Textile Dimension Inspection System Using Zone-Crossing Method, Distortion Angle Classifier and Gray-Level Co-occurrence Matrix Features (영역교차법, 왜곡각 분류자 및 명암도 상관행렬 특징자를 이용한 실시간 섬유 성량 검사 시스템)

  • 이응주;이철희
    • Journal of Korea Multimedia Society
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    • v.3 no.2
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    • pp.112-120
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    • 2000
  • In this paper, we implement a real-time textile dimension inspection system. It can detect various types of real defects which determine the quality of fabric product, defect positions of textile, classify the distortion angel of moving textile and the density. In the implemented system, we measure the density of textile using zone-crossing method with optical lens to solve the noise and real-time problems. And we compensate distortion angel of textile with the classification of distortion types using gaussian gradient and mean gradient features. And also, it detecs real defects of textile and its positions using gray level co-occurrence matrix features. The implemented texile demension inspection systemcan inspect textile dimensions such as density, distortion angle, defect of textile and defect position at real-time. In the implemented proposed texitile dimension inspection system, It is possible to calculate density and detect default of textile at real-time dimension inspection system, it is possible to calculate density and detect default of textile at textile states throughout at all the significant working process such as dyeing, manufacturing, and other texitle processing.

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Development of Stochastic Decision Model for Estimation of Optimal In-depth Inspection Period of Harbor Structures (항만 구조물의 최적 정밀점검 시기 추정을 위한 추계학적 결정모형의 개발)

  • Lee, Cheol-Eung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.28 no.2
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    • pp.63-72
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    • 2016
  • An expected-discounted cost model based on RRP(Renewal Reward Process), referred to as a stochastic decision model, has been developed to estimate the optimal period of in-depth inspection which is one of critical issues in the life-cycle maintenance management of harbor structures such as rubble-mound breakwaters. A mathematical model, which is a function of the probability distribution of the service-life, has been formulated by simultaneously adopting PIM(Periodic Inspection and Maintenance) and CBIM(Condition-Based Inspection and Maintenance) policies so as to resolve limitations of other models, also all the costs in the model associated with monitoring and repair have been discounted with time. From both an analytical solution derived in this paper under the condition in which a failure rate function is a constant and the sensitivity analyses for the variety of different distribution functions and conditions, it has been confirmed that the present solution is more versatile than the existing solution suggested in a very simplified setting. Additionally, even in that case which the probability distribution of the service-life is estimated through the stochastic process, the present model is of course also well suited to interpret the nonlinearity of deterioration process. In particular, a MCS(Monte-Carlo Simulation)-based sample path method has been used to evaluate the parameters of a damage intensity function in stochastic process. Finally, the present stochastic decision model can satisfactorily be applied to armor units of rubble mound breakwaters. The optimal periods of in-depth inspection of rubble-mound breakwaters can be determined by minimizing the expected total cost rate with respect to the behavioral feature of damage process, the level of serviceability limit, and the consequence of that structure.

Seroprevalence of Paratuberculosis in Pure-bred Breeding Cattle in Korea (국가 종축우에 대한 요네병 항체 양성률 조사)

  • Kim, Ha-Young;Byun, Jae-Won;Jeon, Albert Byung-Yun;Park, Bum-Soo;Jung, Ji-A;Park, Mi-Hak;Lim, Yeon-Su;Jung, Byeong-Yeal
    • Journal of Life Science
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    • v.22 no.6
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    • pp.794-798
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    • 2012
  • Paratuberculosis (Johne's disease), a chronic wasting disease caused by Mycobacterium avium subspecies paratuberculosis (MAP), is a major cause of economic loss in the cattle industry. In Korea, national monitoring of breeding stock for MAP has been implemented. In this study, we report the results of serological testing to determine the prevalence of MAP in breeding stock of Korean native and dairy cattle during 2008 and 2009. A total of 3,927 serum samples were submitted (3,692 Korean native cattle and 235 dairy cattle) to Animal Disease Diagnostic Division, Animal, Plant and Fisheries Quarantine and Inspection Agency. The samples were classified into four different age groups for MAP; group 1 (${\leq}2$ year, n = 1,509), group 2 (>2 years to ${\leq}3$ years, n = 486), group 3 (>3 years to ${\leq}4$ years, n = 441), and group 4 (>4 years, n = 1,491). Overall seroprevalence of MAP in this study was 0.5% (21/3,927), which was much lower than that of conventional cattle (1.2-16.4%) in Korea. Also, the seroprevalence was determined by age groups: three of group 1 (0.2%), two of group 2 (0.4%), three of group 3 (0.7%), and 13 of group 4 (0.9%) were seropositive for MAP, respectively. Although seropositive samples were found in all age groups, the seroprevalence tended to increase with age. Our study showed that the seroprevalence of MAP in pure-bred breeding dairy cattle (0%) was lower than that in pure-bred breeding Korean native cattle (0.6%).

Residue analysis and risk assessment of ethoxyquin and ethoxyquin dimer in farmed fish (양식어류 중 Ethoxyquin과 Ethoxyquin dimer의 잔류분석 및 위해평가)

  • Choi, Young-Hee;Ko, Suk-Kyung;Ryu, Seung-Hee;Jin, Young-Hee;Kwak, Jae-Eun;Lee, Myung-Sook;Kim, Bog-Soon;Hang, In-Sook
    • Korean Journal of Food Science and Technology
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    • v.53 no.3
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    • pp.239-244
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    • 2021
  • In the present study, liquid chromatography tandem-mass spectrometry was used to conduct a risk assessment of ethoxyquin and ethoxyquin dimer residues in 288 farmed fish sold in wholesale and traditional markets in Seoul. The detection range (detection rate) of ethoxyquin and ethoxyquin dimer was 0.005~0.309 mg/kg (4.9%) and 0.001~2.828 mg/kg (69.8%), respectively. Ethoxyquin was detected only in freshwater eels, loaches, catfish, and flatfish, whereas ethoxyquin dimer was present in all fish species. To estimate the dietary exposure levels of ethoxyquin and ethoxyquin dimer, the hazard index, calculated using the acceptable daily intake and estimated daily intake, ranged from 0.001 to 0.300%. Our results indicate that there is no significant exposure risk to humans from these farmed fish despite 10 farmed fish samples exceeding the maximum residue level (1.0 mg/kg as the sum of ethoxyquin and ethoxyquin dimer).