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Detection of Apple Defects Using Machine Vision (컴퓨터 시각에 의한 사과 결점 검출)

  • 서상룡;성제훈
    • Journal of Biosystems Engineering
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    • v.22 no.2
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    • pp.217-226
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    • 1997
  • This study was to develop a machine vision system to detect and to discriminate 5 kinds of apple surface defectbruise, decay. fleck, worm hole and scar. To detect the defects from an image of apple, thresholding technique was applied to images on various frames (R, G, B, H, S and I) of the color machine vision and an image of near infrared (NIR). To discriminate the detected region of defect, various features of the 5 kind defect regions were extracted from the 4 kinds of images selected above. The features were size of area, roundness, axes length ratio, mean and valiance of pixel values, standard deviation of real part of amplitude spectrum in frequency domain obtained by Fourier transform of pixel data and mean and standard deviation of power spectrum obtained by the same transform of pixel data. Routines to discriminate the defects from the features of image were developed and tested to prove their validity. The test resulted that I-frame and NIR images were the most desirable. Accuracies of the two images to discriminate the defects were noted as 76% and 77%, respectively.

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Zn(II)porphyrin Helical Arrays: A Strategy to Overcome Conformational Heterogeneity by Host-Guest Chemistry

  • Yoon, Zin-Seok;Easwaramoorthi, Shanmugam;Kim, Dong-Ho
    • Bulletin of the Korean Chemical Society
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    • v.29 no.1
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    • pp.197-201
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    • 2008
  • Conformational heterogeneity of directly linked multiporphyrin arrays with larger molecular length retards their utilities in practical applications such as two-photon absorption and molecular photonic wire. In this regard, here we adopted a way to overcome the conformational heterogeneity through hydrogen bonding by selective binding of meso aryl substituents of porphyrins (host) with urea (guest) to form helical structure. Using steady-state and time-resolved spectroscopy, we observed the enhanced fluorescence quantum yield by ~1.8 to 2.4 times, enhanced anisotropy values and the disappearance of fast fluorescence decay component in the host-guest helical forms. In addition, the enhanced nonlinear optical responses of helical arrays infer the extended inter-porphyrin electronic coupling due to a significant change in dihedral angle between the neighboring porphyrin moieties. The current host-guest strategy will provide a guideline to improve the structural homogeneity of the photonic wire.

Diffusion of Cosmic Rays in a Multiphase Interstellar Medium Shocked by a Supernova Remnant Blast Wave

  • Roh, Soonyoung;Inutsuka, Shu-ichiro;Inoue, Tsuyoshi
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.2
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    • pp.38.1-38.1
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    • 2015
  • Supernova remnants (SNRs) are one of the most energetic astrophysical events and are thought to be the dominant source of Galactic cosmic rays (CRs). A recent report on observations of gamma rays from the vicinity of SNRs have shown strong evidence that Galactic CR protons are accelerated by the shock waves of the SNRs. The actual gamma-ray emission from pion decay should depend on the diffusion of CRs in the interstellar medium. In order to quantitatively analyze the diffusion of high-energy CRs from acceleration sites, we have performed test particle numerical simulations of CR protons using a three-dimensional magnetohydrodynamics (MHD) simulation of an interstellar medium swept-up by a blast wave. We analyse the CRs diffusion at a length scale of order a few pc, and show the Richtmeyer-Meshkov instability can provide enough turbulence downstream of the shock to make the diffusion coefficient close to the Bohm level for energy larger than 30 TeV for a realistic interstellar medium.

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A technique for the reduction of pulse pile-up effect in pulse-shape discrimination of organic scintillation detectors

  • Nakhostin, M.
    • Nuclear Engineering and Technology
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    • v.52 no.2
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    • pp.360-365
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    • 2020
  • A technique for the reduction of pulse pile-up effect in digital pulse-shape discrimination (PSD) of neutrons and gamma-rays with organic scintillation detectors is presented. The technique is based on an electronic reduction of the effective decay-time constant of scintillation pulses while retaining the PSD information of the pulses. The experimental results obtained with a NE213 liquid scintillation detector in a mixed radiation field of neutrons and gamma-rays are presented, demonstrating a figure of merit (FOM) of 1.20 ± 0.05 with an energy threshold of 350 keVee (electron equivalent energy) when the effective length of the pulses is reduced to 50 ns.

Growth and Decay of Alpha Tracks in a Large Scale Cloud Chamber after Injection of Radon

  • Wada, Shinichi;Kobayashi, Tsuneo;Katayama, Yoshiro;Iwami, Toshiaki;Kato, Tsuguhisa;Cameron, John R.
    • Proceedings of the Korean Society of Medical Physics Conference
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    • pp.275-278
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    • 2002
  • The recognition of the natural background radiation is important not only for radiological education but also for the promotion of people's scientific view about radiation. We made a "room" on the web showing natural background radiation as part of a VRM (Virtual Radiation Museum). The "room" shows the video images of the tracks of charged particles from natural background radiation, alpha and beta ray track from known sources using a Large Scale Diffusion Cloud Chamber. The purpose of this study is to make clear the origin of a kind of track (named A-track) which is thick and easy to recognize with the length less than several cm in the cloud chamber, and to make numerical explanation of its counting rate. The study was carried out using a Large Scale Diffusion Cloud Chamber (Phywe, Germany) installed in the Niigata Science Museum. The Model RNC (Pylon Electronics, Canada) was used as Rn-222 source. Ra-226 activity in RNC was 111.6 Bq calibrated with NIST protocol. Rn-222 gas was injected into the cloud chamber. Continuous video recording with use of Digital Handycam (SONY, Japan) was carried out for 360 min. after injection of Rn-222 gas. The number of alpha-ray track (alpha track) in the video images was analyzed. The growth and decay curve of the total activity of Rn-222 and its alpha emitting progeny were calculated and compared with the count of the alpha tracks. As a result the alpha tracks formed by Rn-222 injection resemble A-Tracks. The relationship between A-track in the cloud chamber and atmospheric Rn is discussed.

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Combustion Stability Test of LRE Thrust Chamber using Artificial Perturbation Method (강제교란 방법을 이용한 액체로켓엔진 연소기의 연소안정성 시험)

  • Lee, Kwang-Jin;Seo, Seong-Hyeon;Han, Yeoung-Min;Choi, Hwan-Seok;Ko, Young-Sung
    • Journal of the Korean Society of Propulsion Engineers
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    • v.14 no.3
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    • pp.52-60
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    • 2010
  • Combustion stability tests of 30 $ton_f$-class LRE thrust chamber with double swirl coaxial injector were carried out in domestic ground combustion test facility by means of artificial perturbation method. In these tests, thrust chambers with varying design factors like recess number of injector, baffle length, types of film cooling and chamber diameter were used and test results showed that these design factors are closely related with high frequency combustion stability. By using the oscillation decrement instead of the decay time in the combustion stability analysis of artificially perturbed LRE thrust chamber, it was confirmed that increment of damping factor results in the improvement of high frequency combustion stability of LRE thrust chamber.

Assessment of Levee Slope Reinforced with Bio-polymer by Image Analysis (영상분석을 통한 바이오폴리머로 보강된 제방사면 안정성 해석)

  • Ko, Dongwoo;Kang, Joongu
    • Ecology and Resilient Infrastructure
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    • v.6 no.4
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    • pp.258-266
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    • 2019
  • This study was conducted to apply natural river technologies to levees and examine the results. The new eco-friendly bio-polymer was applied, a combination of eco-friendly biopolymers and soil, to levee slope to enhance durability and eco-friendliness and to establish reinforcement measures against unstable levees due to overtopping. A semi-prototype levee of 1 m in height, 3 m in width, with a 1:2 slope and 5 m length, was constructed at the Andong River Experiment Center. The bio-soil mixed with the biopolymer and the soil at an appropriate ratio was treated with a 5 cm thickness on the surface of levee to perform the stability evaluation according to overtopping. Using the pixel-based analysis technique using the image analysis program, the breached area of levee slope was calculated over time. As a result, the time for complete decay occurs more than 12 times than that of ordinary soil levee. Therefore, when the new substance is applied to the surface of levee, the decay delay effect appears to be high.

Yield Loss of Spring Chinese Cabbage as Affected by Infection Time of Clubroot Disease in Fields (봄배추 무사마귀병의 포장 감염시기와 피해)

  • 김충회;조원대;김홍모
    • Research in Plant Disease
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    • v.6 no.1
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    • pp.23-26
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    • 2000
  • Effects of infection time of the clubroot pathogen, Plasmodiophora brassicae, on yield loss of Spring-sown Chinese cabbage plants were examined in field experiments. Yield loss of Chinese cabbage plants increased as the infection time becomes early. Plants infected at 20 days after transplanting or earlier were completely killed before harvest, and those infected at 30 days after transplanting were healthy in appearance but their head weights were reduced to 59% with poor commodity value. The plants infected 40 days after transplanting were not affected in yield. Development of root hairs in diseased plants was greatly reduced as the infection progressed, and root length was reduced to 1/2 to 1/3 of that of healthy plants. root galls were first developed 20 days after inoculation and rapidly enlarged to reach the peak in size 20 days from initial development, and decayed thereafter. Development and decay of root galls tended to be faster at later season as air temperature became high, regardless of the infection time. Diseased plants started to wilt approximately 10 days after root gall development. Root galls began to decay 10 days after initial plant wilting, and then were completely rotten within following 10 days. Based on the results, root gall development stages on spring-sown Chinese cabbage plants could be grouped into 20 days of root gall enlargement period, and 10 days of root gall decay period, followed by survival period in soil.

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An Improved Concept of Deep Geological Disposal System Considering Arising Characteristics of Spent Fuels From Domestic Nuclear Power Plants (국내 원자력발전소에서의 사용후핵연료 발생 특성을 고려한 심층 처분시스템 개선)

  • Lee, Jongyoul;Kim, Inyoung;Choi, Heuijoo;Cho, Dongkeun
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.17 no.4
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    • pp.405-418
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    • 2019
  • Based on spent fuels characteristics from domestic nuclear power plants and a disposal scenario from the current basic plan for high-level radioactive waste management, an improved disposal system has been proposed that enhances disposal efficiency and economic effectiveness compared to the existing disposal system. For this purpose, two disposal canisters concepts were derived from the length of the spent fuel generated from the nuclear power plants. In the disposal scenario, the acceptable amount of decay heat for each disposal container was determined, taking into account the discharge and disposal times of spent fuels in accordance with the current basic plan. Based on the determined decay heat of the two types of disposal canisters and the associated disposal system, thermal stability analyses were performed to confirm their suitability to the proposed disposal system design requirement and disposal efficiency assessment. The results of this study confirm 20% reduction in the disposal area and 20% increase in disposal density for the proposed disposal system compared to the existing system. These results can be used to establish a spent fuel management policy and to design a viable commercial disposal system.

Radial Variation in Selected Wood Properties of Indonesian Merkusii Pine

  • Darmawan, Wayan;Nandika, Dodi;Afaf, Britty Datin Hasna;Rahayu, Istie;Lumongga, Dumasari
    • Journal of the Korean Wood Science and Technology
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    • v.46 no.4
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    • pp.323-337
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    • 2018
  • Merkusii pine wood (Pinus merkusii) was extensively planted throughout Indonesia, where it is only indigenous in northern Sumatera, by the Dutch during colonial times. The demand for this wood species, especially in the domestic market, has increased notably, despite its limited durability regarding decay resistance. The purpose of this study was to investigate the occurrence of juvenile and mature wood on merkusii pine and to analyze its radial features from pith to bark based on density, shrinkage, static bending in modulus of rupture and modulus of elasticity, fiber length, microfibril angle, and durability. A segmented modeling approach was used to find the juvenile-mature transition. The graveyard test was performed to characterize the termite resistance from pith to bark of merkusii pine. The maturations were estimated to start at radial increments of 15 cm from the pith by fiber length and of 12 cm from the pith by microfibril angle. The projected figures for the proportion of juvenile wood at breast height were around 65%. The results also indicate that the pine wood was $0.52g/cm^3$ in density, 1.45 in coefficient of anisotropy, which indicates its good stability, 7597 MPa in modulus of elasticity, and 63 MPa in modulus of rupture. Natural durability against subterranean termite of the merkusii pine wood was rated to be grade 4 to 0 from pith to bark. However, after being treated by Entiblu and Enborer preservatives, its rating increased to grade 10 to 9.