Earticle

Ionization chambers often exhibit a stem effect, caused by interactions of radiation with air near the chamber end, or with dielectric in the chamber stem or cable. In this study measured stem effect correction factor for length of ionization chamber from medical linear accelerator recommend to with the use of stem correction method. For a model of the Farmer-type chamber, were used to calculate the beam quality correction factor. These interactions contribute to the apparent measured exposure. Additionally, it needs to consider ionization chamber use of small volume and stem effect of cable by a large field. Linear accelerator generated photons energy and increased dose repeatedly measured by using stem correction method. Stem effect was dependence of the energy and increases with photon energy conditions improved of beam quality. In conclusion, stem effect correction factor was measured within 0.4% calculated according to the exposures stem length and also supposed to determined below 1% of another stem correction method.

미세먼지를 측정하기 위하여 사용되고 있는 광산란법 장비를 보다 정확하게 운영하기 위하여 중량법 측정결과를 기준으로 보정계수를 산정하였다. 2013년 5월 제주도 애월읍에서 채취된 시료의 표본개수는 장비별로 각각 5개로, PM2.5 농도는 광산란법이 중량법과 베타선법에 비하여 약 2배 가량 높은 수준으로 나타났으며, 최소자승법을 이용한 중량법과 광산란법, 베타선흡수법과 광산란법의 선형회귀직선의 기울기를 보정계수로 산정한 결과 그 값은 각각 0.57, 0.61이었다. 계절과 장소에 따라 미세먼지의 밀도에 차이가 있음을 고려할 때 광산란법 측정결과는 중량법 또는 이와 동등한 측정방법을 기준으로 보완될 필요가 있으며, 이에 따른 보정계수 산정은 지속적으로 수행되어야 할 것으로 판단된다.

In order to more accurately operate the Dusttrak equipment of optic scattering measurement used for measurement ofthe fine particle (PM2.5), the correction factor of optic scattering was estimated based on the result of gravimetricmeasurement. The number of samples taken in the spring of 2013 was 5 days respectively, the average PM2.5 concentrationof optic scattering was shown to be about 2 times higher than that of gravimetric and β-ray method; and the result ofestimating the gradient of the linear regression line between the gravimetric and optic scattering, between the β-ray methodand optic scattering as the correction factor using ordinary least squares were shown to be 0.57 and 0.61 respectively. Considering that PM2.5 density varies depending on the season and place, it is presumed that the estimation of thecorrection factor is required to be conducted continuously.

선형가속기의 선량평가를 위한 멸균증류수를 사용 시 보존기간에 따른 불순물 유입 으로 탁도가 변화로 선량값의 오차가 발생하게 된다. 이에 탁도 측정을 통한 멸균증류 수 교체기준 및 교정계수를 획득하고자 한다. 물팬텀 내 멸균증류수를 2주 간격으로 8회에 걸쳐 탁도를 측정하고 10MV 광자선을 이용하여 선량을 측정하였다. 측정결과 탁도증가에 따른 선량오차는 비례관계를 보이며, 허용오차인 3%에 대치되는 탁도는 2.8 NTU로 나타났다. 이를 통해 선량측정 시 탁도를 측정하여 해당 교정계수에 적용 하여야 하며, 탁도가 2.8 NTU를 넘는 경우에는 멸균증류수를 교체하여야 할 것이다. 향후 이를 통해 선형가속기의 절대선량 평가가 별도로 이루어진 실험 및 탁도의 세분 화에 따른 교정계수 산출을 통한 연구의 기틀을 마련하고자 하였다.

전완부와 요추부의 골밀도 검사를 통해 얻은 골밀도 값, T-score 와 Z-score수치간의 상관관계 및 보정함수 를 구해 어느 한 부위의 결과로서 다른 부위의 결과를 유추하는데 목적이 있다. 환자 66명은 연령별로 11명씩 20대 에서 70대까지 환자들로 구성하였고 측정된 전완부와 요추부의 골밀도와 T-score와 Z-score를 조사하여 세가지 사항 들에 대해 각각 상관관계가 있는지 평가하고 그 상관관계를 구하여 보정계수를 찾는다. 골밀도의 상관계수는 R=0.769 이고 보정계수 식은 Y=1.541X + 0.133 이다. T-score의 상관계수는 R=0.768 이고 보정계수식은 Y=0.715X - 0.4 이다. Z-score의 상관계수는 R=0.635 보정계수식은 Y=0.751X - 0.162 이다. 상관관계와 보정계수식를 통해 어 느 한 부위의 결과로서 다른 부위의 결과를 유추할 수 있는 임상적 유용성이 있을 것으로 사료된다.

The Forearm and the lumbar spine bone mineral density bone mineral density values obtained through, T-score and Z-score correlation between numerical and calibration function obtained as a result of any one part to another part of the results is intended to infer. Groups of 66 patients, 11 patients by age 20-70 were composed of patients measured with the forearm and lumbar spine bone mineral density T-score and Z-score of the survey for each of the three factors that correlated to assess the correlation Find the correction factor to obtain the relationship. Bone mineral density of the correlation coefficient R = 0.769 correction factor is Y = 1.541X + 0.133. T-score of correlation coefficient R = 0.768 and the correction factor Y = 0.715X - 0.4 is Z-score of the correlation coefficient R = 0.635 correction factor Y = 0.751X - 0.162 It is regarded that there will be a clinical availability which can analogize the result of a part by using the result of the other part.

혈압측정은 오랜 시간동안 외부압력을 이용하여 혈관 압력 대응값으로 계산해왔다. 최근 측정 장비의 소형화와 의료네트워크 기술의 발전으로 개인 건강관리시스템의 활성화로 인해 간단한 센서로 혈압을 연속적이며 실시간 측정이 가 능한 환경을 요구하고 있다. 본 연구에서는 광전용적맥파를 적용하고 맥파전달시간을 이용하여 혈압을 추정하고자 한다. 기존 방식은 신체 변수값 등으로 개인 오차를 줄여 측정하는 알고리즘을 사용하고 있으나, 광전용적맥파의 분석과 맥파전달 시간의 적용방법에 따라 정확도가 떨어진다. 본 연구에서는 기존 수축기 혈압을 이용하여 혈압을 유추하는 융합적인 방법을 선택하여 적용하였다. 그리고 광전용적맥파 자체로만 혈압 추정이 가능하게 구성하여 초소형 혈압측정시스템을 만드는데 필요한 융합알고리즘을 제공하고자 하였다. 그 결과 수축기혈압과 광전용적맥파의 최대, 최소 주기간격을 이용하여 혈압 추정 융합 알고리즘의 가능성을 상관관계로 분석하였다.

The blood pressure measurement is calculated as a value corresponding to the pressure of the blood vessel using the pressure from the outside for a long time. Due to the recent miniaturization of measurement equipment and the ICT combination of personal healthcare systems, a system that enables continuous and real-time measurement of blood pressure with a sensor is required. In this study, blood pressure was measured using pulse transit time using Photoplethysmography. In this study, blood pressure was estimated by using systolic blood pressure. And it is possible to make measurement only with PPG itself, which can contribute to making a micro blood pressure measuring device. As a result, systolic blood pressure and PPG's S1-P and P-S2 were used to analyze the possibility of blood pressure estimation.

고조파에 의한 전기설비 사고와 경제적 손실은 증가하고 있다. 고조파 수동 필터는 고조파를 억제하는데 효과적이고 경제적이지만, 많은 현장 엔지니어들은 고조파 증폭과 병렬 공진 발생 등의 문제점으로 인해 계통에 수동 고조파 필터를 설치하는 것을 꺼려한다. 본 논문에서는 이러한 문제점을 해결하기 위해 역률 보상을 기반으로 하는 고 조파 수동필터 제어기를 개발하였다. 개발된 시스템의 전압 및 전류 측정 정확도는 표준 전력 발생장비인 FLUKE 61000A를 이용하여 시험하였으며, 측정 정확도는 0.5% 이하로 나타났다.

Accidents of electric equipment and economical loss by harmonics show a rising tendency. A passive filter is economic and efficient in suppressing harmonics. But many engineers and designers are reluctant to install a passive filter to defect harmonics at their power system because of problems such as harmonic amplification and the probability of generating series or parallel resonance with the power system. This work have developed harmonic passive filter controller based on power factor correction that passive filters. The volated and current measurement accuracy of the developed system is tested by using electrical power standard devices FLUKE 61000A. The test results showed that accuracy of the developed system is less than 0.5 %

본 연구는 승인 국가온실가스 배출계수를 활용한 미시적 수준의 수송부문 온실가스 배출량 산정을 목적으로 종단경사 보정계수 개발 및 적용 방안을 제시하였다. 배출량 보정계수 개발에 는 미국 환경청에서 사용중인 MOVES-Matrix가 활용되었으며, 국내/외 차/유종 분류체계 간 매 칭을 통해 총 16종의 차/유종에 대한 보정계수 산정이 이뤄졌다. 다만 시나리오 분석에 있어, 현재 활용가능한 데이터가 국내 교통정보 수집시스템 내 일반 차종 3종(승용차, 버스, 트럭)이기 에, 일반차종기준 보정계수를 추가로 개발하였다. 종단경사의 경우 링크와 격자단위로 산출된 데이터의 장단점이 존재하여, 이를 각각 활용하였다. 분석 결과 종단경사가 증가할수록 온실가 스 단위배출량이 증가하였으며, 링크 대비 격자단위 종단경사가 고려되었을 때 온실가스 배출 량 차이가 크게 나타났다. 보정계수 적용 비교 시나리오별로 약 12~15%의 온실가스 배출량의 차이가 발생하였으며, 종단경사가 배출량에 유의한 영향을 미침을 확인할 수 있다. 수송부문 온실가스 배출 중 도로발생 비중이 높은만큼, 종단경사 보정계수에 대한 고려가 향후 지자체 중심의 온실가스 감축전략 수립 및 평가분석 시 유용한 지표로써 활용될 것으로 판단된다.

While ongoing efforts and studies have been made to reduce greenhouse gas (GHG) emissions, less attention has been placed on calibrating discrepancies between calculated emissions and real-world emissions. However, since over 90% of emissions in the transportation system originate from roads, applying a precise model to calculate emissions and assess reduction policies is essential. As advanced form of calculating emissions, this study introduces correction factor application method designed to be adaptable to Korea’s official emission model, referred to as the GIR Basic Model. In the process of adaptation, correction factors were initially developed for 16 vehicle/fuel types in Korea, aligned with the U.S. vehicle/fuel classification system. Later, based on available data, these 16 categories were aggregated into three main vehicle categories: Passenger Car, Bus, and Truck. Moreover, since high variability in the length of road segments within the dataset could lead to inconsistencies with gradient values, potentially affecting the accuracy of the results, we also considered methods to minimize the length dependency in gradient calculation. Regarding the results from both link-based and grid-based gradients, we chose to use both datasets and conducted comparison scenarios. Scenarios reveal that GHG emission increased with road gradients, with grid-based gradients showing more significant emission differences compared to link-based gradients. Quantitatively, applying road gradients resulted in a 12-15% change in MAPE bewteen models, and considering gradients led to a reduction in overall emissions. Due to the frequent variations in terrain, including uphills and downhills, across Korea, it is essential to consider road gradients not only for accurate emission assessments at the local government level but also for informing policies aimed at mitigating emissions through gradient modifications.

This paper proposes fluorescent electronic ballast with high power factor and low line input current harmonics. The system performance can be improved by a charged pump circuit. Details of design and circuit operation are described. The proposed electronic ballast is modified from single - stage half bridge class D electronic ballast by adding capacitor parallel with each power switch and setting the circuit parameter to operate under class DE inverter condition. By using this proposed method the DC bus voltage can be reduced around by 50% compare with conventional class D inverter circuit. Because the power switches are operated at zero voltage switching condition and low dv/dt of class DE switching. The experimental results show that the proper frequency of the prototype is around 50 kHz with input power factor of 0.982, THDi 10.2% at full load and efficiency of more than 90%.

In this paper, the proposed system is to improve power factor of switched reluctance drive and also battery charging capability in regenerative mode of a two-stage power converter based on current source rectifier (CSR). At the CSR stage in the input of SRM converter, eliminate dc link's capacitors and the charging capability of energy saving in regenerative operation mode of SRM drive. And also it controls the speed and current. This paper describes the design of new converter, consisting of half-bridge IGBT modules and Current source rectifiers with battery charging capability of SRM for closed loop control of switched reluctance drive are proposed. The validity and effectiveness of the proposed approach is shown by MATLAB /simulation.

HPGe 검출기를 이용하여 밀도가 다양한 환경시료에 대한 정밀 분석시 정확한 분석을 위해서는 밀도보정인자가 필요하다. 밀도에 대한 보정인자를 구하기 위해서 본 연구에서는 몬테카를로 코드인 MCNPX 코드를 사용하여 크리스털의 높이, 지름및 코어의 크기와 같은 특성이 다른 세 대의 p-type HPGe 검출기를 모사하고 밀도 1 g/cm3의 교정용 표준시료를 이용하여 모델링을 검증하였다. 검증을 통하여 모델링을 확정한 후 0.3, 0.6, 0.9, 1.0, 1.2, 1.5 g/cm3 밀도를 가진 샘플에 대한 효율을 시뮬레이션하고 밀도보정인자를 도출하였다. 도출된 각 검출기에 대한 밀도보정인자를 비교하였을 때 전 에너지 범위에서 그차이가 거의 없음을 확인하였으며 이는 검출기의 크리스털과 같은 주요 특성에 대해 밀도보정인자가 독립적임을 의미한다.

The precise determination of the activity for each radionuclide in environmental samples requires the self-absorption correction factor. In this research, we derived the self-absorption correction factor for three p-type high purity germanium detectors using the Monte Carlo code MCNPX. These detectors have different characteristics such as crystal diameter, height and size of the core. We compared the calculated full-energy peak efficiency with the experimental value using a standard sample with 1 g/cm3 density and verified the modeling. We simulated the dependency of the full-energy peak efficiency on the 0.3, 0.6, 0.9, 1.0, 1.2 and 1.5 g/cm3 samples and obtained the corresponding self-absorption correction factor. The self-absorption correction factors calculated for the three detectors differ by less than 1% over most of the energy range and sample densities considered. This indicates that the self-absorption correction factors are independent of the crystal characteristics of HPGe detector.

본 논문에서는 SMPS(Switch-Mode Power Supply)의 역률을 개선할 수 있는 power factor correction(PFC) IC를 설계하였다. 설계된 PFC IC에는 전원장치의 power MOSFET을 구동할 수 있는 기능 이외에도 과전압, 과전류 및 단락보호 기능이 포함되어 있다. 또한 시스템이 대기상태에 있는 경우, 전압 및 전류 feedback 제어에 의해 효과적으로 대기전력을 절감할 수 있도록 설계하였다. 설계된 PFC IC는 시스템이 대기상태에서 일정시간동안 부하변동이 없을 경우 이를 감지하여 자동으로 시스템을 off 시켜 대기전력 소모를 최소화 하는 기능을 포함하고 있다.

In this paper, we design and implement the monolithic power factor correction IC for system power modules using a high voltage(50V) CMOS process. The power factor correction IC is designed for power applications, such as refrigerator, air-conditioner, etc. It includes low voltage logic, 5V regulator, analog control circuit, high-voltage high current output drivers, and several protection circuits. And also, the designed IC has standby detection function which detects the output power of the converter stage and generates system down signal when load device is under the standby condition. The simulation and experimental results show that the designed IC acts properly as power factor correction IC with efficient protective functions.

In this paper, we design and implement the monolithic zero crossing detection power factor correction IC using a high voltage 30V BCD process. The ZCD PFC IC is designed for power applications, such as notebook, LCD monitor, etc. It includes power factor correction function and several protection circuit, regulator, high-voltage high current output drivers. And also, the designed IC has restart timer function which the output pulse is generated if the output signal of IC is not in a 200us. The simulation results show that the designed IC acts properly as power factor correction IC with efficient protective functions.

Previously, many researchers assessed nearshore wave energy in two ways. The first is a simulation with respect to the offshore wave time series to validate the wave buoy data and the wave model results, and the other is to simulate the representative waves of typical seasonal wave conditions. The former requires enormous computational time and effort. The latter yields inspection on the patterns for the spatial and temporal distribution of nearshore wave energy but tends to underestimates the amount of wave energy in the nearshore region owing to the correlation between the significant wave height and wave period. $\ddot{O}$zger et al. (2004) derived the stochastic wave energy formulation by introducing a correction factor explicitly in terms of the covariance of the wave energy and significant wave height. In this study, a correction factor was applied for the assessment of nearshore wave energy obtained by numerical simulation of wave transformation with respect to representative waves.

<P>Ratio correction factor and phase displacement of instrument transformers vary with the values of the external burden connected to the secondary of the transformers. Using the values measured at two burdens of the instrument transformers, the ratio correction factor and phase displacement at arbitrary burdens are theoretically obtained without any additional measurement. This is based on a theoretical analysis of the equivalent circuits of the instrument transformers. The validity of the methods was verified by comparing the theoretical value with measured value for several instrument transformers with different accuracy.</P>

Monitoring sunspots consistently is the most basic step required to study various aspects of solar activity. To achieve this goal, the observers must regularly calculate their own correction factor $k$ and keep it stable. Relatively recently, two observing teams in South Korea have presented interesting papers which claim that revisions that take the yearly-basis $k$ into account lead to a better agreement with the international relative sunspot number $R_i$, and that yearly $k$ apparently varies with the solar cycle. In this paper, using artificial data sets we have modeled the sunspot numbers as a superposition of random noise and a slowly varying background function, and attempted to investigate whether the variation in the correction factor is coupled with the solar cycle. Regardless of the statistical distributions of the random noise, we have found the correction factor increases as sunspot numbers increase, as claimed in the reports mentioned above. The degree of dependence of correction factor $k$ on the sunspot number is subject to the signal-to-noise ratio. Therefore, we conclude that apparent dependence of the value of the correction factor $k$ on the phase of the solar cycle is not due to a physical property, but a statistical property of the data.