• Journal of Radiation Protection and Research
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• v.31 no.4
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• pp.165-171
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• 2006

In Korea, a real-time effective dose measurement system is in development. The system uses 32 high-sensitivity MOSFET dosimeters to measure radiation doses at various organ locations in an anthropomorphic physical phantom. The MOSFET dosimeters are, however, mainly made of silicon and shows some degree of energy and angular dependence especially for low energy photons. This study determines the correction factors to correct for these dependences of the MOSFET dosimeters for accurate measurement of radiation doses at organ locations in the phantom. For this, first, the dose correction factors of MOSFET dosimeters were determined for the energy spectrum in the steam generator channel of the Kori Nuclear Power Plant Unit #1 by Monte Carlo simulations. Then, the results were compared with the dose correction factors from 0.652 MeV and 1.25 MeV mono-energetic photons. The difference of the dose correction factors were found very negligible $(\leq1.5%)$, which in general shows that the dose corrections factors determined from 0.662 MeV and 1.25 MeV can be in a steam general channel head of a nuclear power plant. The measured effective dose was generally found to decrease bit $\sim7%$ when we apply the dose correction factors.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.11
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• pp.1134-1142
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• 2003

This paper presents a hardware implementation of the STS diversity system, utilizing FPGAs and introduces the function and the design method of each of the modules of the system. In order to improve the performance of the implemented STS system which is an open loop transmit diversity system under fading environment, the exact estimation of the communication channel is essential. Therefore, we propose the optimal forgetting factor to estimate pilot channel in this paper, It is shown in this paper that the pilot channel is estimated using the forgetting factor of 0.7 without increasing the integration range of the pilot channel even when the power of pilot channel is not sufficiently large in CDMA 2000 1x signal environment.

• Journal of Radiation Protection and Research
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• v.16 no.1
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• pp.15-24
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• 1991

Radon-222 exhalation rate from several domestic building materials were experimentally measured by using radon cup method, in which a CR-39 plastic is used as a passive radon detector. The radon detection factor of CR-39 detector determined in a series of calibration experiments was $0.164{\pm}0.005(tracks\;cm^{-2}/Bq\;d\;m^{-3})$, which is consistent with those reported by other investigators. The radon exhalation rates of several building materials (brick, red brick, concrete block, granite plate, concrete floor and wall) ranges from $6.8{\times}10^{-6}\;(granite plate)\;to\;75.0{\times}10^{-6}Bq/m^2-sec(brick)$ with the increasing order of granite plate, red brick, concrete wall, concrete block, concrete floor and brick. It showed that the CR39 radon cup can be efficiently utilized in measuring the radon-222 gas exhalation rate from building materials.

• The Science & Technology
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• s.526
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• pp.64-67
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• 2013

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.795-798
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• 2000

연속음 인식과 음성 합성을 위해서는 정밀한 음성학적 모델과 연속 음성에 적용 가능한 언어 모델의 개발이 중요하다. 이를 위해서는 음성 데이터 베이스에 대한 인식 단위, 혹은 합성 단위의 분할이 필요한데, 수동음성 분할은 일관성의 유지가 어렵고 긴 시간이 소요되므로 최근에는 자동 분할 기술이 많이 연구되고 있다. 자동 음성 분할 기법으로는 시간 영역이나 주파수 영역특징 벡터의 천이를 분석하는 방법과 특징 벡터간의 상관도를 구하여 경계를 추출하는 방법이 있다. LPC smoothed log amplitude spectra는 음성의 주파수 영역의 특징을 잘 나타내며, 동일 음소 내의 상관도가 서로 다른 음소의 상관도보다 더 크고, 음소의 경계구간에서 급격한 상관도의 변화를 보인다. 이 특성을 이용하여 이웃 프레임에 대한 상관도의 방향성이 특정조건을 만족하는가를 검사하여 음소의 경계를 구하는 방법을 찾았다. 또한 LPC. 이득 인자만으로 묵음 구간을 검출하는 방법을 제시한다. 이렇게 하면 묵음 구간검출과 음소 경계 검출의 일관성을 향상시키고 수행 시간을 단축시킬 수 있다. 제안한 기법으로 허용 오차 20ms 이내에서 연속음성에 대한 음소 경계 검출 실험을 수행한 결과, 수작업으로 행한 경계 검출 지점의 약 88%를 정확히 검출하였다.

• The Korean Journal of Applied Statistics
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• v.7 no.2
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• pp.201-211
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• 1994

Ignoring interaction effects has been pointed out to be one of serious drawbacks in analysis of the parameter designs which are constructed by using orthogonal arrays. In this paper a detecting procedure of influential 2-factor inteactions with minimum expeimental runs is described, when each contrl factor has two levels. The presented method is based on the near orthogonal arrays which are very similar to orthogonal arrays in the statistical structure. And those arrarys are the same as trace-optimal balanced saturated two-level fractional factorial designs of resolution V.

• Journal of Advanced Navigation Technology
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• v.15 no.3
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• pp.471-477
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• 2011

A wide distribution of CCTV cameras in many public areas can be used not only for video surveillance systems but also for preserving fire occurrence. A proposed approach is based on visual information through a static camera. Video sequences are analyzed to find fire candidates and then spatial analyses procedure for detected fire-like color foreground is carried out. If spatial and temporal variances changes rapidly and close to fire motion, fire candidate is considered as fire.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.545-550
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• 2004

An Image processing algorithm was developed and tested to detect abnormal parts, such as esophagitis, with the information on the color and the texture in a digital clinic endoscopic image by using discriminal analysis. In order to develope the algorithm, the critical parameters from many parameters were found to distinguish between normal and abnormal part in the various images. The Inflammation and ulceration which are very important diagnostic indexes were detected by the algorithm. The algorithm proved to a reliable program for detecting abnormal parts with 20 images. A success rate was 92.8% and 92.4% in the calibration stage and the validation stage by using the algorithm with discriminal analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.1-8
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• 2016

We propose an adaptive histogram stretching algorithm for application to a car's personal recorder. The algorithm was used for pre-processing to detect the license plate region in an image from a personal recorder. The algorithm employs a Probability Density Function (PDF) and Cumulative Distribution Function (CDF) to analyze the distribution diagram of the images. These two functions are calculated using an image obtained by sampling at a certain pixel interval. The images were subjected to different levels of stretching, and experiments were done on the images to extract their characteristics. The results show that the proposed algorithm provides less deterioration than conventional algorithms. Moreover, contrast is enhanced according to the characteristics of the image. The algorithm could provide better performance than existing algorithms in applications for detecting search regions for license plates.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.503-510
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• 2020

Concrete is one of the most widely used materials as the shielding structures of a nuclear facilities. It is also the most generated radioactive waste in quantity while dismantling facilities. Since the concrete captures neutrons and generates various radionuclides, radiation measurement and analysis of the sample was fulfilled prior to dismantle facilities. An HPGe detector is used in general for the radiation measurement, and effective correction factors such as geometrical correction factor, self-absorption correction, and absolute detector efficiency have to be applied to the measured data to decide exact radioactivity of the sample. Correction factors are obtained by measuring data using a standard source with the same geometry and chemical states as the sample under the same measurement conditions. However, it is very difficult to prepare standard concrete sources because concrete is limited in pretreatment due to various constituent materials and high density. In addition, the concrete sample obtained by core drill is a volumetric source, which requires geometric correction for sample diameter and self absorption correction for sample density. Therefore in recent years, many researchers are working on the calculation of effective correction factors using Monte carlo simulation instead of measuring them using a standard source. In this study we calculated, using Geant4, one of the Monte carlo codes, the correction factors for the various diameter and density of the concrete core sample at the gamma ray energy emitted from the nuclides ¹⁵²Eu and ⁶⁰Co, which are the most generated in radioactive concrete.