• Journal of the Korean Society of Radiology
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• v.8 no.7
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• pp.423-428
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• 2014

Digital X-ray imaging devices using a TFT based flat panel array has been used in medical field. But, recently, lots of research on the photon counting sensor has been reported. In this study, we evaluated the physical properties of the photoconductor by suggesting the standard and testing method for quantitative performance evaluation of photon counting x-ray imaging sensor. First, we measured the leakage current and the sensitivity of photon counting x-ray imaging sensor and we evaluated the characteristic of rising time for determining the signal shaping time. In addition, the set-up study was conducted on the basis of the IEC 62220-1-2 recommendations to define the number of incident photons per unit area. And the efficiency of the charge collection was also evaluated. As a result, the characteristic was measured as $200pA/mm^2$ of the leakage current, $7{\mu}C/cm^2R $ of the X-ray sensitivity, and $0.765{\mu}s$ of the rising time.

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.299-303
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• 2001

Using ultrasound techniques, the Korea Atomic Energy Research Institute has measured chest wall thicknesses of a group of male workers at the Korea Atomic Energy Research Institute. A site-specific biometric equation has been developed for these workers. Chest wall thickness is an important modifier on lung counting efficiency. These data have been put into the perspective of the ICRP recommended dose limits for occupationally exposed workers: 100 mSv in a 5-year period with a maximum of 50 mSv in anyone year. For measured chest wall thicknesses of 1.9 cm to 4.1 cm and a 30 min counting time, the achievable MDAs for natural uranium in the KAERI lung counter vary from 5.75 mg to 11.28 mg. These values are close to, or even exceed, the predicted amounts of natural uranium that will remain in the lung (absorption type M and S) after an intake equal to the Annual Limit on Intake corresponding to a committed dose of 20 mSv. This paper shows that the KAERI lung counter probably cannot detect an intake of Type S natural uranium in a worker with a chest wall thickness equal to the average value (2.7 cm) under routine counting conditions.

• 보존과학연구
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• s.15
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• pp.21-32
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• 1994

Optimum conditions for benzene synthesis and liquid scintillation counting have been studied for the determination of radiocarbon age. In benzene synthesis the carbon dioxide converted to benzene with high efficiency of 91%. Yields of each step with 10L of carbon dioxide were $CO_2$ $\rightarrow$$C_2H_2$(94%), $C_2H_2$$\rightarrow$$C_6H_6$(96%) and$CO_2$$\rightarrow$$C_6H_6$(91%), respectively. Benzene synthesized from oxalate was measured with purity of 95% by GC /MS. $\delta^13$(C$^13$C/$^12$C) of oxalate was measured to $-24.7\{textperthousand}$ by massspectrometer. For liquid scintillation counting of benzene sample low background and highest FOM were measured in 0.5 ml cocktail and 3 ml standard solution with the range of 15.4∼74.9 KeV window setting. Oxalate and background samples weremeasured to $28.7\pm0.12$cpm and $3.92\pm0.04$ cpm in 15.4∼74.9 KeV

• Applied Biological Chemistry
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• v.18 no.2
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• pp.56-60
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• 1975

A rapid method for the measurement of the absolute activity of carbon-14 in cotyledons and root of etiolated pea seedlings has been developed. Fresh tissue was frozen in liquid air, ground and suspended in gel phosphor and subjected to measurement for its radioactivity by liquid scintillation counter. Apparent activity of the suspended tissue sample calculated by counting efficiency value obtained by internal standardisation, was found to be related to absolute activity of the tissue, determined by flask combustion technique, by a constant factor. Once this factor is determined experimentally, analysis of C-14 lebelled tissue involves only fairly simple suspension counting by liquid scintillation counter. Present method appears to be applicable to other tissues tagged with C-14.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.4
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• pp.332-339
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• 2014

Face classification has wide applications in security and surveillance. However, this technique presents various challenges caused by pose, illumination, and expression changes. Face recognition with long-distance images involves additional challenges, owing to focusing problems and motion blurring. Multiple frames under varying spatial or temporal settings can acquire additional information, which can be used to achieve improved classification performance. This study investigates the effectiveness of multi-frame decision-level fusion with photon-counting linear discriminant analysis. Multiple frames generate multiple scores for each class. The fusion process comprises three stages: score normalization, score validation, and score combination. Candidate scores are selected during the score validation process, after the scores are normalized. The score validation process removes bad scores that can degrade the final output. The selected candidate scores are combined using one of the following fusion rules: maximum, averaging, and majority voting. Degraded facial images are employed to demonstrate the robustness of multi-frame decision-level fusion in harsh environments. Out-of-focus and motion blurring point-spread functions are applied to the test images, to simulate long-distance acquisition. Experimental results with three facial data sets indicate the efficiency of the proposed decision-level fusion scheme.

• Journal of Information Processing Systems
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• v.18 no.3
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• pp.428-442
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• 2022

A reliable automatic passenger counting (APC) system is a key point in transportation related to the efficient scheduling and management of transport routes. In this study, we introduce a lightweight head detection network using deep learning applicable to an embedded system. Currently, object detection algorithms using deep learning have been found to be successful. However, these algorithms essentially need a graphics processing unit (GPU) to make them performable in real-time. So, we modify a Tiny-YOLOv3 network using certain techniques to speed up the proposed network and to make it more accurate in a non-GPU environment. Finally, we introduce an APC system, which is performable in real-time on embedded systems, using the proposed head detection algorithm. We implement and test the proposed APC system on a Samsung ARTIK 710 board. The experimental results on three public head datasets reflect the detection accuracy and efficiency of the proposed head detection network against Tiny-YOLOv3. Moreover, to test the proposed APC system, we measured the accuracy and recognition speed by repeating 50 instances of entering and 50 instances of exiting. These experimental results showed 99% accuracy and a 0.041-second recognition speed despite the fact that only the CPU was used.

• Journal of Radiation Protection and Research
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• v.42 no.2
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• pp.83-90
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• 2017

Background: Different cases exist in the measurement of thyroid radiobioassays owing to the individual characteristics of the subjects, especially the potential variation in the counting efficiency. An In situ Object Counting System (ISOCS) was developed to perform an efficiency calibration based on the Monte Carlo calculation, as an alternative to conventional calibration methods. The purpose of this study is to evaluate the applicability of ISOCS to thyroid radiobioassays by comparison with a conventional thyroid monitoring system. Materials and Methods: The efficiency calibration of a portable high-purity germanium (HPGe) detector was performed using ISOCS software. In contrast, the conventional efficiency calibration, which needed a radioactive material, was applied to a scintillator-based thyroid monitor. Four radioiodine samples that contained $^{125}I$ and $^{131}I$ in both aqueous solution and gel forms were measured to evaluate radioactivity in the thyroid. ANSI/HPS N13.30 performance criteria, which included the relative bias, relative precision, and root-mean-squared error, were applied to evaluate the performance of the measurement system. Results and Discussion: The portable HPGe detector could measure both radioiodines with ISOCS but the thyroid monitor could not measure $^{125}I$ because of the limited energy resolution of the NaI(Tl) scintillator. The $^{131}I$ results from both detectors agreed to within 5% with the certified results. Moreover, the $^{125}I$ results from the portable HPGe detector agreed to within 10% with the certified results. All measurement results complied with the ANSI/HPS N13.30 performance criteria. Conclusion: The results of the intercomparison program indicated the feasibility of applying ISOCS software to direct thyroid radiobioassays. The portable HPGe detector with ISOCS software can provide the convenience of efficiency calibration and higher energy resolution for identifying photopeaks, compared with a conventional thyroid monitor with a NaI(Tl) scintillator. The application of ISOCS software in a radiation emergency can improve the response in terms of internal contamination monitoring.

• Journal of Environmental Science International
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• v.14 no.12
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• pp.1163-1170
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• 2005

The microbial adsorption characteristics of two different media for biological treatment were studied using attached diverse microbes onto activated carbon and ceramic. The results in the experiments of the characteristics of physical adhesion on two different media with addition of high and low concentrated substrate in the culture were observed that the efficient of adhesion onto F-400 activated carbon was higher over that of ceramic due to the surface area of media. The irradiation treatment by ultrasonication with 400 W power and 3 min retention time on the media without addition substrate conditions and subsequent mixing throughly the culture showed the highest efficiency of cell detachment on the media. Three different microbes, P. ovalis, A calcoaceticus, and B. subtillis were used for the study of the characteristics of microbial adhesion on the media. p ovalis showed the highest adhesion capability while B. subtillis showed the lowest capability adhesion onto media either addition of substrate in the culture. The mixed bacterial culture showed $10\%$ lower removal efficiency of DOC in the low concentrated substrate culture compared to the single pure culture. Whileas, it did not show significant difference between two cultures at high concentrated substrate. It was also observed same population density of microorganism by counting of microbes adhered to microbial media with an ultrasound treatment.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1259-1265
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• 2020

A beta ray scanner was proposed for in-situ discrimination of beta and gamma ray radioactivity. This scanner is based on the principle that gamma and beta rays experience different changes in detection efficiency in scintillators with different geometries, especially with regard to the scintillator thickness. The ratios of the counting rates of gamma rays (R_gamma), beta rays (R_beta), and sample measurements (R_total) in a thick scintillator to those in a thin one are reported. The parameter X_thick, which represents the counting rate contributed by beta rays to the total counting rate in the thick scintillator, was derived as a function of those ratios. The values of R_gamma and R_beta for ⁶⁰Co and ⁹⁰Sr sources were estimated as 3.2 ± 0.057 and 0.99 ± 0.0049, respectively. The estimated beta ray contributions had relative standard deviations of 2.05-4.96%. The estimated range of the beta rays emitted from ⁹⁰Sr was 19 mm as per the Monte Carlo N-Particle simulation, and this value was experimentally verified. Homogeneous and surface contaminations of ⁶⁰Co and ⁹⁰Sr-⁹⁰Y were simulated for application of the proposed method. The counting rate contributed by the beta rays was derived and found to be proportional to the concentration of ⁹⁰Sr-⁹⁰Y contamination.

• Journal of the Korea Furniture Society
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• v.24 no.2
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• pp.131-139
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• 2013

The efficiency of internet lectures has been proved in many areas, and its significance and role theory has been consistently mentioned in the fields of furniture design education that demand a large amount of educational contents and practice in visual education. However, it reveals weaknesses without satisfying the demand owing to various realistic issues. In this study, the significance and developmental process of internet lecture as well as its effect after the development in terms of the education on furniture design were analyzed by counting some development cases of internet educational program in relation with AutoCAD educational course, a computer design program for furniture design. Also through such analysis, it intended to promote the development of design education by assessing the merits and problems, assignments to be supplemented, and utilization of the educational course development.