• 방송공학회논문지
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• 제22권6호
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• pp.702-712
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• 2017

본 논문에서는 신호 구조에 가중치 맵으로써 Laplacian을 이용한 언샤프 마스킹과 평균 밝기에 가중치 맵으로써 영상의 평균 밝기를 이용한 감마 변환 알고리듬을 제안하고자 한다. 패치를 기반으로 한 기존의 가중치 맵은 신호 구조 및 평균 밝기 영역에서 영상 내 밝기 값이 한쪽으로 치우쳐 세부 정보가 손실되는 단점이 있다. 본 논문에서는 패치 단위의 언샤프 마스킹을 이용하여 세부정보를 향상시켰고, 전역적 및 지역적 영상의 평균 밝기 값을 이용하여 감마 변환된 값을 선형 결합한 기법을 제안한다. 제안하는 알고리듬은 영상 내 윤곽선과 같은 세부 정보를 보존시키고 빛의 밝기 조절을 통해 주관적 화질을 향상시켰다. 실험 결과를 통해 기존 알고리듬에 비해 제안한 알고리듬이 우수한 성능을 나타내는 것을 확인하였다.

• Nuclear Engineering and Technology
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• 제52권8호
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• pp.1784-1791
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• 2020

The 14 MeV neutron generator facility is being developed by the Institute for Plasma Research India to conduct the lab scale experiments related to Indian breeding blanket system for ITER and DEMO. It will also be utilized for material testing, shielding experiments and development of fusion diagnostics. Occupational radiation exposure control is necessary for the all kind of nuclear facilities to get the operational licensing from governing authorities and nuclear regulatory bodies. In the same way, the radiation exposure for the 14 MeV neutron generator facility at the occupational worker area and accessible zones for general workers should be under the permissible limit of AERB India. The generator is designed for the yield of 10¹² n/s. The shielding assessment has been made to estimate the radiation dose during the operational time of the neutron generator. The facility has many utilities and constraints like ventilation ducts, accessible doors, accessibility of neutron generator components and to conduct the experiments which make the shielding assessment challenging to provide proper safety for occupational workers and the general public. The neutron and gamma dose rates have been estimated using the MCNP radiation transport code and ENDF -VII nuclear data libraries. The ICRP-74 fluence to dose conversion coefficients has been used for the assessment. The annual radiation exposure has been assessed by considering 500 h per year operational time. The provision of local shield near to neutron generator has been also evaluated to reduce the annual radiation doses. The comprehensive results of radiation shielding capability of neutron generator building and local shield design have been presented in the paper along with detailed maps of radiation field.

• 미생물학회지
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• 제24권3호
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• pp.243-250
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• 1986

Candida pseudotropicalis CBS 607에서의 야생형과 영양요구성 돌연변이 균주에 대한 원형질체 형성 및 재생과 상보적 영양요구성 균주간의 융합에 관해서 연구하였다. 야생형과 his tidine 혹은 adenine요구성 균주에서 원형질체 형성율은 96-100%이였으나 methionine과 tryptophan요구성 균주는 각각 52%와 72%였다. Myoinositol (0.5 mg/ml)을 첨가한 배지에서 전배양한 methionine과 tryptophan조 구성 균주는 원형질체 형성시 bovine serum albumin (BSA, 4 mg/ml)을 첨가하면 96-98%의 원형질체 형성율이 얻어졌다. 원형질체 재생 빈도는 18-20% 였으나. BSA와 myoinositol을 첨가하면 adenine요구성 균주(약 20%)을 제외한 나머지 영양요구성 균주에서는 재생율이 20% 이상 증가했다. 원형질체 융합에 대한 PEG와 $CaCl_2$,최적농도는 20%와 100mM이었고 최적 pH와 반 응시간은 각각 6.0과 30분이 있다. 상보적 영양요구성 균수의 융합빈도는 $1.5{\times}10^{-3}\;to\;8.8{\times}10^{-3}$ 였으며 원행점체의 재생 증진으로 인해 융합율이 현저히 증가했다. Histidine요구성 균주와 tryptophan 요구성 균주을 융합시켰을 때 몇개의 융합세포를 얻었는데 측정된 DNA양과 액상의 차이로 보아 aneuploid나 diploid상태임을 알 수 있었다.

• 생태와환경
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• 제43권3호
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• pp.409-417
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• 2010

본 연구는 Pb의 농도와 노출 기간이 붕어(Carassius auratus) 조직의 미세구조와 생리적 변화에 미치는 영향을 조사하였다. 아가미, 뼈와 근육 조직에서 Pb의 축적 농도는 노출 40일에 증가하였다. 아가미 조직 내 Pb의 축적량은 다른 조직에 비하여 높았으며, 아가미, 뼈 및 근육 조직에서 노출기간이 길어질수록 증가하였다. Pb에 노출된 아가미, 뼈와 근육 조직의 항산화효소 활성은 아가미와 근육 조직에서 높았으며, 신장 조직에서 가장 낮은 활성을 보였다. 또한 항산화효소 중 superoxide dismutase의 활성은 대조군에 비해 2배 정도 증가하였으나, glutathion peroxidas의 활성은 매우 낮았다. Pb에 노출된 아가미 조직에서 점액세포는 수가 증가하였으며, 곤봉화와 부종이 이차새변에서 나타났다. 또한 40일간 Pb에 노출된 아가미 조직 내 미토콘드리아와 핵에서는 막의 손상이 관찰되었으며, 신장 조직 내 사구체는 수축되어 보우만 주머니의 공간이 넓게 관찰되었다. 이러한 결과로 보아 붕어 조직 이 장기간 고농도의 Pb에 노출이 되면 비정상적인 형태로 변형되며, 이에 따라 매우 유해한 영향을 받을 수 있을 것으로 생각된다.

• Environmental Engineering Research
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• 제15권4호
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• pp.225-230
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• 2010

In order to treat soil contaminated with high percentages of water and petroleum, the combined microwave and thermal desorption process was studied, which was composed of the consecutive connection of two pre-treatment processes. For the thickness of the contaminated soil layer on the transfer conveyor belt, the optimal total petroleum hydrocarbon (TPH) removal rate was studied with respect to the duration of microwave exposure in the consecutive process combined with thermal desorption. The TPH removal rate when the contaminated soil layer thickness was 1 cm at 6 kW of microwave power was 80%. The removals rates for 2 and 3 cm soil layer thicknesses were both 70%. Under identical experimental conditions, the TPH removal rate for the microwave pre-treatment, when considering the soil particle size, was over 70%. The lowest TPH removal rate was achieved with a particle diameter of 2.35 mm. For contaminated soil with 30% water content, 6 kW and a thermal desorption temperature of $600^{\circ}C$ were the optimal operational conditions for the removal of THP. However, considering the fuel consumption cost, 4 kW and a thermal desorption temperature of $300^{\circ}C$ would be the most economic conditions.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.465-469
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• 2006

In recent years there has been considerable interest in the construction of super high-rise buildings. From the prior art, various procedures and devices for surveys during and after the phase of erection of a high-rise building are known. High-rise buildings are subject to strong external tilt effects caused, for instance, by wind pressures, unilateral thermal effects by exposure to sunlight, and unilateral loads. Such effects are a particular challenge in the phase of construction of a high-rise building, in as much as the high-rise building under construction is also subject to tilt effects, and will at least temporarily lose its - as a rule exactly vertical - alignment. Yet construction should progress in such a way that the building is aligned as planned, and particularly so in the vertical, when returning into an un-tilted basic state.It is essential that a straight element be constructed that theoretically, even when moving around its design centre point due to varying loads, would have an exactly vertical alignment when all biasing conditions are neutralised. Because of differential raft settlement, differential concrete shortening, and construction tolerances, this ideal situation will rarely be achieved. This paper describes a procedure developed by the authors using GPS observations combined with a network of precision inclination sensor to provide reliable coordinated points at the top of the worldwide highest-rise building under construction in Dubai.

• Journal of Korean Neurosurgical Society
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• 제30권7호
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• pp.870-875
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• 2001

Objectives : Anterior tunnelling technique consist of anterior cervical fractional interspace decompression without fusion. This method provides sufficient space for adequate neuroforaminal decompression but avoids the need for fusion or fixation. We report early clinical results of 32 cases that underwent anterior tunnelling operation for treatment of cervical radiculopathy. Methods : This method is identical to conventional approach until the exposure of anterior cervical body and bilateral retraction of longus colli is made. A vertical window is then made at the vertebral bodies and disc space lateral to the insertion site of the longus colli. The window is deepened with drilling that follows a tunnelling fashion down to the compressive lesion. We analyzed clinical results from 32 patients who treated between December 1998 and August 2000. Results : Satisfactory results were obtained in 87% of the patients. Two patients required revision surgery. None revealed surgical spinal instability on last follow-up. Conclusion : Anterior tunnelling operation is an acceptable surgical option for the treatment of cervical radiculopathy. Its advantages are short hospitalization, minimal postoperative discomfort, and technical feasibility.

• ETRI Journal
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• 제46권1호
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• pp.22-34
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• 2024

Exposure to varied noisy environments impairs the recognition performance of artificial intelligence-based speech recognition technologies. Degraded-performance services can be utilized as limited systems that assure good performance in certain environments, but impair the general quality of speech recognition services. This study introduces an audiovisual speech recognition (AVSR) model robust to various noise settings, mimicking human dialogue recognition elements. The model converts word embeddings and log-Mel spectrograms into feature vectors for audio recognition. A dense spatial-temporal convolutional neural network model extracts features from log-Mel spectrograms, transformed for visual-based recognition. This approach exhibits improved aural and visual recognition capabilities. We assess the signal-to-noise ratio in nine synthesized noise environments, with the proposed model exhibiting lower average error rates. The error rate for the AVSR model using a three-feature multi-fusion method is 1.711%, compared to the general 3.939% rate. This model is applicable in noise-affected environments owing to its enhanced stability and recognition rate.

• Nuclear Engineering and Technology
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• 제56권4호
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• pp.1490-1500
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• 2024

Helium-induced defect nucleation and accumulation in polycrystalline W and W0.5 wt%ZrC (W0.5ZrC) were studied in-situ using the transmission electron microscopy (TEM) combined with 40 keV He⁺ irradiation at 800 and 1000℃ at the maximum damage level of 1 dpa. Radiation-induced dislocation loops were not observed in the current study. W0.5ZrC was found to be less susceptible to irradiation damage in terms of helium bubble formation and growth, especially at lower temperature (800 ℃) when vacancies were less mobile. The ZrC particles present in the W matrix pin the forming helium bubbles via interaction between C atom and neighbouring W atom at vacancies. This reduces the capability of helium to trap a vacancy which is required to form the bubble core and, as a consequence, delays, the bubble nucleation. At 1000 ℃, significant bubble growth occurred in both materials and all the present bubbles transitioned from spherical to faceted shape, whereas at 800 ℃, the faceted helium bubble population was dominated in W.

• 전자공학회논문지SC
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• 제44권6호
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• pp.42-48
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• 2007

X-ray 영상 시스템에서는, 크게 2 종류의 noise 성분이 함유되어있다. 먼저 x-ray 방사선이 조사되어질 때, 검출기에서의 방사선의 상호작용으로부터 발생되어지는 것으로서 랜덤하게 발생되어지는 Poisson noise 성분이다. 다음으로 noise 성분은 readout electronics noise, pixel pattern noise 그리고 off-set noise 등으로부터 발생되어지는 Gaussian noise 성분이다. 그러나, x-ray 영상에서는 Gaussian noise가 아닌, Poisson noise로 모델링 되어진다. Gaussian noise에 의해서 발생되어지는 noise 성분은 위너필터 혹은 웨이브렛을 사용하여 쉽게 제거가 가능하지만, Poisson noise와 같은 랜덤 noise를 제거하기 위해서는 복잡한 분석기법이 필요하게 한다. 이 논문에서는 웨이브렛 영역에서 x-ray 영상의 Poisson noise를 제거하고자 하였으며, 적용된 분석 기법은 최적화된 웨이브렛 분석기법인 IBS(Improved BayesShrink)을 사용하였다. 적용된 IBS 기법은 cone-beam CT의 x-ray 영상에서의 기존의 방법에 비해 향상된 결과를 보여주었다.