• 제목/요약/키워드: Donghak

검색결과 86건 처리시간 0.028초

Depth Resolution Analysis of Axially Distributed Stereo Camera Systems under Fixed Constrained Resources

  • Cho, Myungjin;Shin, Donghak
    • Journal of the Optical Society of Korea
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    • 제17권6호
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    • pp.500-505
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    • 2013
  • In this paper, we propose a novel framework to evaluate the depth resolution of axially distributed stereo sensing (ADSS) under fixed resource constraints. The proposed framework can evaluate the performance of ADSS systems based on various sensing parameters such as the number of cameras, the number of total pixels, pixel size and so on. The Monte Carlo simulations for the proposed framework are performed and the evaluation results are presented.

Cancer Activation and Polymorphisms of Human Cytochrome P450 1B1

  • Chun, Young-Jin;Kim, Donghak
    • Toxicological Research
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    • 제32권2호
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    • pp.89-93
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    • 2016
  • Human cytochrome P450 enzymes (P450s, CYPs) are major oxidative catalysts that metabolize various xenobiotic and endogenous compounds. Many carcinogens induce cancer only after metabolic activation and P450 enzymes play an important role in this phenomenon. P450 1B1 mediates bioactivation of many procarcinogenic chemicals and carcinogenic estrogen. It catalyzes the oxidation reaction of polycyclic aromatic carbons, heterocyclic and aromatic amines, and the 4-hydroxylation reaction of $17{\beta}$-estradiol. Enhanced expression of P450 1B1 promotes cancer cell proliferation and metastasis. There are at least 25 polymorphic variants of P450 1B1 and some of these have been reported to be associated with eye diseases. In addition, P450 1B1 polymorphisms can greatly affect the metabolic activation of many procarcinogenic compounds. It is necessary to understand the relationship between metabolic activation of such substances and P450 1B1 polymorphisms in order to develop rational strategies for the prevention of its toxic effect on human health.

Improvement of delayed hydride cracking assessment of PWR spent fuel during dry storage

  • Hong, Jong-Dae;Yang, Yong-Sik;Kook, Donghak
    • Nuclear Engineering and Technology
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    • 제52권3호
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    • pp.614-620
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    • 2020
  • In a previous study, delayed hydride cracking (DHC) assessment of pressurized water reactor (PWR) spent fuel during dry storage using the threshold stress intensity factor (KIH) was performed. However, there were a few limitations in the analysis of the cladding properties, such as oxide thickness and mechanical properties. In this study, those models were modified to include test data for irradiated materials, and the cladding creep model was introduced to improve the reliability of the DHC assessment. In this study, DHC susceptibility of PWR spent fuel during dry storage depending on the axial elevation was evaluated with the improved assessment methodology. In addition, the sensitivity of affecting parameters such as fuel burnup, hydride thickness, and crack aspect ratio are presented.

Position Detection of a Scattering 3D Object by Use of the Axially Distributed Image Sensing Technique

  • Cho, Myungjin;Shin, Donghak;Lee, Joon-Jae
    • Journal of the Optical Society of Korea
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    • 제18권4호
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    • pp.414-418
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    • 2014
  • In this paper, we present a method to detect the position of a 3D object in scattering media by using the axially distributed sensing (ADS) method. Due to the scattering noise of the elemental images recorded by the ADS method, we apply a statistical image processing algorithm where the scattering elemental images are converted into scatter-reduced ones. With the scatter-reduced elemental images, we reconstruct the 3D images using the digital reconstruction algorithm based on ray back-projection. The reconstructed images are used for the position detection of a 3D object in the scattering medium. We perform the preliminary experiments and present experimental results.

렌즈릿 모델에 기초한 컴퓨터 변환을 통한 Orthoscopic 집적 영상 디스플레이 (Orthoscopic Integral Imaging Display by Use of Computational Method Based on Lenslet Model)

  • 신동학;홍석민;이병국
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2012년도 추계학술대회
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    • pp.1015-1018
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    • 2012
  • 본 논문에서는 집적 영상 기술에서 오쏘스코픽 3D 영상을 복원할 수 있는 렌즈 모델에 기초한 컴퓨터 깊이 반전 방법을 제안한다. 제안하는 방법은 임의의 거리에 대해서 깊이 반전된 요소 영상을 생성할 수 있으며, 깊이 반전에 필요한 추가적인 과정이 없다. 렌즈 모델에 기초한 깊이 반전 방법의 유용함을 보이기 위한 기초적인 실험을 수행하고 그 결과를 보고한다.

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NEW SELECTIVE AND POTENT INHIBITORS OF HUMAN CYTOCHROM P450 1A FAMILY ENZYMES

  • F. Peter Guengerich;Chun, Young-Jin;Kim, Sanghee;Kim, Donghak;Lee, Sang-Kwang;Dong, Mi-Sook;Ueng, Yune-Fang
    • 한국독성학회:학술대회논문집
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    • 한국독성학회 2001년도 International Symposium on Dietary and Medicinal Antimutgens and Anticarcinogens
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    • pp.37-38
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    • 2001
  • The cytochrome P450 (P450) 1 family (1A1, 1A2, 1B1) is involved in the activation of many pro-carcinogens. Previously we characterized a number of synthetic bi- and polycyclic hydrocarbon acetylenes as selective-mechanism-based inhibitors of recombinent P450s 1A1, 1A2, 1B1 (Shimada et al., Chem. Res. Toxicol., 11, 1048-1056, 1998). We reported that the drug oltipraz is a mechanism-based indicator of P450 1A2 (Lagouet et al. Chem. Res. Toxicol., 13, 245-252, 2000).(omitted)

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Uterine leiomyosarcoma in a cat

  • Na, Hyemin;Choi, Donghak;Son, Woo-Chan;Lee, Kija
    • 대한수의학회지
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    • 제60권3호
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    • pp.179-182
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    • 2020
  • A 16-year-old cat presented with a 2-week history of anorexia and lethargy. Radiography revealed a soft-tissue opacity, heart-shaped mass between the descending colon and urinary bladder. Ultrasonography showed a large uterine body with a heterogeneously hypoechoic, thickened wall and hypoechoic intraluminal fluid. Computed tomography revealed a large, fluid-filled uterine mass with contrast enhancement, without evidence of regional lymph node or pulmonary metastasis. Ovariohysterectomy was performed and leiomyosarcoma was confirmed by histology. No notable abnormalities were observed during the 1-year postoperative follow-up periods. This report describes the diagnostic imaging and treatment of a rare case of feline uterine leiomyosarcoma.

Resolution Analysis of Axially Distributed Image Sensing Systems under Equally Constrained Resources

  • Cho, Myungjin;Shin, Donghak
    • Journal of the Optical Society of Korea
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    • 제17권5호
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    • pp.405-409
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    • 2013
  • In this paper, a unifying framework to evaluate the depth resolution of axially distributed image sensing (ADS) systems under fixed resource constraints is proposed. The proposed framework enables one to evaluate the system performance as a function of system parameters such as the number of cameras, the number of pixels, pixel size, and so on. The Monte Carlo simulations are carried out to evaluate ADS system performance as a function of system parameters. To the best of our knowledge, this is the first report on quantitative analysis of ADS systems under fixed resource constraints.

3D Integral Imaging Display using Axially Recorded Multiple Images

  • Cho, Myungjin;Shin, Donghak
    • Journal of the Optical Society of Korea
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    • 제17권5호
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    • pp.410-414
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    • 2013
  • In this paper, we propose a 3D display method combining a pickup process using axially recorded multiple images and an integral imaging display process. First, we extract the color and depth information of 3D objects for displaying 3D images from axially recorded multiple 2D images. Next, using the extracted depth map and color images, elemental images are computationally synthesized based on a ray mapping model between 3D space and an elemental image plane. Finally, we display 3D images optically by an integral imaging system with a lenslet array. To show the usefulness of the proposed system, we carry out optical experiments for 3D objects and present the experimental results.

Successful Treatment of Ulna Fracture in a Small Raptor

  • Kim, Taeil;Jeong, Hyo-Hoon;Choi, Donghak;Yun, Sungho;Kwon, Young-Sam
    • 한국임상수의학회지
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    • 제35권6호
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    • pp.266-268
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    • 2018
  • A wild Falco tinnunculus, which is a small raptor, was rescued and presented due to immobilization. On physical examination, a left ulnar fracture was detected, which was reduced with an intramedullary (IM) pin and soft bandaging. Passive range of motion (PROM) exercises were then conducted to prevent complications such as ankylosis. The raptor was released into the wild four weeks postoperatively. We suggest that IM pinning with bandaging and appropriate PROM exercises may effectively treat ulnar fractures in small raptors.