• Nuclear Engineering and Technology
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• 제49권3호
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• pp.504-516
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• 2017

The Jordan Research and Training Reactor (JRTR) is the first research reactor in Jordan, the commissioning of which is ongoing. The reactor is a 5-MWth, open-pool type, light-water-moderated, and cooled reactor with a heavy water reflector system. The neutron measurement system (NMS) applied to the JRTR employs a wide-range fission chamber that can cover from source range to power range. A high-sensitivity boron trifluoride counter was added to obtain more accurate measurements of the neutron signals and to calibrate the log power signals; the NMS has a major role in the entire commissioning stage. However, few case studies exist concerning the application of the NMS to a research reactor. This study introduces the features of the NMS and the boron trifluoride counter in the JRTR and shares valuable experiences from lessons learned from the system installation to its early commissioning. In particular, the background noise relative to the signal-to-noise ratio and the NMS signal interlock are elaborated. The results of the count rates with the neutron source and the effects of the discriminator threshold are summarized.

• 한국임상약학회지
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• 제28권3호
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• pp.167-173
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• 2018

Background: In July 2016, the Infectious diseases society of america and the american thoracic society (IDSA & ATS) published a guideline recommending piperacillin/tazobactam (Pip/Tazo) 18 g/day as the anti-pseudomonal dose for the treatment of pathogenic pneumonia. After the guideline was published, the Pip/Tazo dose used for the treatment of pathogenic pneumonia was changed from 13.5 g/day to 18 g/day in a superior general hospital intensive care unit (ICU). In this study, we analyzed the effectiveness and safety of the new dose. Methods: Adult patients aged ${\geq}19years$ who were diagnosed with pneumonia in ICU and who received Pip/Tazo for 7 days or more from September 1, 2015 to May 31, 2017 were included in the study. The electronic medical record (EMR) was retrospectively analyzed. Results: At baseline, there was a significant difference between 44 patients treated with 13.5 g/day and 31 patients treated with 18 g/day of Pip/Tazo. The 18 g/day-treatment group comprised more elderly patients than the 13.5 g/day-treatment group (p=0.028). The results of the treatment-effects analysis showed no significant difference between the two groups. In case of safety data, there were significant differences in two parameters related to blood count, namely hemoglobin (p=0.016) and platelet count (p=0.011). Conclusion: Based on the significant difference in baseline age, there is a possibility that high-dose Pip/Tazo showed improved therapeutic effect. However, when high-dose Pip/Tazo was used, the blood cell count was found to drop from the reference value more frequently. Therefore, blood cell count should be monitored carefully when high-dose Pip/Tazo is administered.

• Journal of Radiation Protection and Research
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• 제42권3호
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• pp.158-165
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• 2017

Background: Nuclear facilities in South Korea have generally adopted pressurized ion chambers to measure ambient gamma ray exposure rates for monitoring the impact of radiation on the surrounding environment. The rates assessed with pressurized ion chambers do not distinguish between natural and man-made radiation, so a further step is needed to identify the cause of abnormal variation. In contrast, using NaI(Tl) scintillation detectors to detect gamma energy rates can allow an immediate assessment of the cause of variation through an analysis of the energy spectra. Against this backdrop, this study was conducted to propose a more effective way to monitor ambient gamma exposure rates. Materials and Methods: The following methods were used to analyze gamma energy spectra measured from January to November 2016 with NaI detectors installed at the Korea Atomic Energy Research Institute (KAERI) dormitory and Hanbat University. 1) Correlations of the variation of rates measured at the two locations were determined. 2) The dates, intervals, duration, and weather conditions were identified when rates increased by $5nSv{\cdot}h^{-1}$ or more. 3) Differences in the NaI spectra on normal days and days where rates spiked by $5nSv{\cdot}h^{-1}$ or more were studied. 4) An algorithm was derived for automatically calculating the net variation of the rates. Results and Discussion: The rates measured at KAERI and Hanbat University, located 12 kilometers apart, did not show a strong correlation (coefficient of determination = 0.577). Time gaps between spikes in the rates and rainfall were factors that affected the correlation. The weather conditions on days where rates went up by $5nSv{\cdot}h^{-1}$ or more featured rainfall, snowfall, or overcast, as well as an increase in peaks of the gamma rays emitted from the radon decay products of $^{214}Pb$ and $^{214}Bi$ in the spectrum. This study assumed that $^{214}Pb$ and $^{214}Bi$ exist at a radioactive equilibrium, since both have relatively short half-lives of under 30 minutes. Provided that this assumption is true and that the gamma peaks of the 352 keV and 1,764 keV gamma rays emitted from the radionuclides have proportional count rates, no man-made radiation should be present between the two energy levels. This study proved that this assumption was true by demonstrating a linear correlation between the count rates of these two gamma peaks. In conclusion, if the count rates of these two peaks detected in the gamma energy spectrum at a certain time maintain the ratio measured at a normal time, such variation can be confirmed to be caused by natural radiation. Conclusion: This study confirmed that both $^{214}Pb$ and $^{214}Bi$ have relatively short half-lives of under 30 minutes, thereby existing in a radioactive equilibrium in the atmosphere. If the gamma peaks of the 352 keV and 1,764 keV gamma rays emitted from these radionuclides have proportional count rates, no man-made radiation should exist between the two energy levels.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1161-1166
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• 2011

A camera is mounted vertically downwards viewing the people heads from the top. This configuration is successful in people counting technique especially when only a few isolated people pass through a counting region in a non-crowded situation. Thus, this paper describes object counting which detects and count moving people using mixture of gaussian and motion vector. This method is intended to estimates the number of people in outdoor environment. This method use single gaussian background modeling which is more robust an noise and has adaptiveness. The experimental results that is based on mixture of gaussian and motion vector is also helpful to design intelligent surveillance.

• 한국전기전자재료학회논문지
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• 제30권3호
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• pp.148-151
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• 2017

This research concerns field rings for 3.3kV planar gate power insulated-gate bipolar transistors (IGBTs). We design an optimal field ring for a 3.3kV power IGBT and analyze its electrical characteristics according to field ring parameters. Based on this background, we obtained 3.3kV high breakdown voltage and a 2.9V on state voltage drop. To obtain high breakdown voltage, we confirmed that the field ring count was 23, and we obtained optimal parameters. The gap distance between field rings $13{\mu}m$ and the field ring width was $5{\mu}m$. This design technology will be adapted to field stop IGBTs and super junction IGBTs. The thyristor device for a power conversion switch will be replaced with a super high voltage power IGBT.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.335-338
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• 2003

The recognition limit of brightness difference in the visual system of human has not been studied system-atically. In this paper, endeavor to calculate surround adapted Weber-Fechner fractions based on the crispening effect was added to the traditional Weber-Fechner fractions. It is found that surround adapted fractions have reduced to 1/3 of the traditional fractions. As compared with Breitmeyer's experiments, the presented result is a reasonable one. It can be used as some guide to design the digital display system when a designer needs to decide bit count of digital signal in considering of the limit of brightness level, and as the inspection tool of display manufacturing of brightness smear, defect, and so on.

• Tuberculosis and Respiratory Diseases
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• 제73권3호
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• pp.169-173
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• 2012

Background: Spontaneous pneumomediastinum is a rare and benign condition that generally occurs in young generations without any precipitating factor or underlying disease. The purpose of this study is to review our experience in dealing with this entity and detail a reasonable course of assessment and management. Methods: From December 1999 to May 2012, 32 spontaneous pneumomediastinum patients were managed in our hospital. We retrospectively reviewed the result of management. Results: Patients ranged in age from 10 to 38 years, with the mean age of $18.3{\pm}5.6$ years. Twenty-five patients were men and seven were women. Initial WBC count was $10,039{\pm}2,993/{\mu}L$ and thirty-one patients underwent computed tomography. Twenty-two patients underwent esophagography and results were shown to be normal. Twenty-five patients were admitted in the hospital and the mean duration of admission was $3.4{\pm}2.0$ days. All patients were managed conservatively and discharged without any complications. Conclusion: Spontaneous pneumomediastinum is a benign condition combined with mild inflammatory signs and secondary causes must to excluded to avoid unfavorable outcomes and select proper management modality.

• 전자공학회논문지S
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• 제35S권3호
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• pp.131-143
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• 1998

This paper presents a high performance disparity extraction algorithm that generate a dense and accurate disparity map using low-resolution disparity histogram. Disparity distribution of background and object areas can besegmented from low-resolution disparity histogram. These information can be used to reduce the search area and search range of the high-resolution image resulting reliable disparity information in high speed. The computationally efficient matching pixel count(MPC) similarity measure technique is useed extensively toremove the redundancies inherent in the area-based matching method, and also results robust matching at the boundary region. Resulting maches are further improved using iterative support algorithm and post processing. We have obtained good results on randomdot stereogram and real images obtained in our carmera system.

• 대한방사선기술학회지:방사선기술과학
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• 제8권2호
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• pp.77-81
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• 1985

In this experiments the operation of the Geiger-Mueller tube is investigated by measuring the relationship between the count rate and the applied voltages, The length and slope of the plateau are characteristic of the tube. In our experiments, the average plateau length of the tube is extend for about 100 [V] and the slope 0.017 [%/V]. For normal counting purposes the working voltage is usually selected at value about 50 volts larger than the threshold of the plateau. To investigate the absorption of beta particles by matter. We performed an absorption experiments by using the Al absorber and Sr-90 ($0.125{\mu}Ci$) beta source. The maximum range of the beta radiation can be determined by visual extrapolation of the curve after subtraction of the constant background-rate and the maximum beta energy 2.09 [MeV] can be calculated from the range using an experimental relation.

• 한국광학회:학술대회논문집
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• 한국광학회 2001년도 제12회 정기총회 및 01년도 동계학술발표회
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• pp.246-247
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• 2001

짧은 파장의 레이저 빔이 비선형 결정에 입사할 때 긴 파장의 두 광으로 자발적으로 변환하는 매개 하향변환(parametric down-convension; PDC)과정을 통해서 양자적 상관관계를 갖는 광원을 얻을 수 있다. PDC 과정은 에너지 보존 (w$_{p}$ = w$_{s}$ ＋ w$_{i}$)과 운동량 보존 (k$_{p}$ = k$_{s}$ ＋ k$_{i}$)에 해당하는, 위상조화 (phase matching) 조건이 잘 만족할 때 효과적으로 일어난다. PDC에서 광자들이 아주 짧은 시간에 쌍으로 발생한다는 것과 이러한 광자쌍을 동시에 측정하는(coincidence count; 동시계수) 방법을 이용하면 효과적으로 신호와 잡음을 분리해 낼수 있고, 배경(background)이나 잡음(noise)보다 미약한 신호를 통해서도 정보를 전달할 수 있는 가능성을 제공해준다. (중략)