• 한국의학물리학회지:의학물리
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• 제31권4호
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• pp.145-152
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• 2020

Purpose: In ionization-chamber dosimetry for high-dose-rate electron beams-above 20 mGy/pulse-the ion-recombination correction methods recommended by the International Atomic Energy Agency (IAEA) and the American Association of Physicists in Medicine (AAPM) are not appropriate, because they overestimate the correction factor. In this study, we suggest a practical ion-recombination correction method, based on Boag's improved model, and apply it to reference dosimetry for electron beams of about 100 mGy/pulse generated from an electron linear accelerator (LINAC). Methods: This study employed a theoretical model of the ion-collection efficiency developed by Boag and physical parameters used by Laitano et al. We recalculated the ion-recombination correction factors using two-voltage analysis and obtained an empirical fitting formula to represent the results. Next, we compared the calculated correction factors with published results for the same calculation conditions. Additionally, we performed dosimetry for electron beams from a 6 MeV electron LINAC using an Advanced Markus^® ionization chamber to determine the reference dose in water at the source-to-surface distance (SSD)=100 cm, using the correction factors obtained in this study. Results: The values of the correction factors obtained in this work are in good agreement with the published data. The measured dose-per-pulse for electron beams at the depth of maximum dose for SSD=100 cm was 115 mGy/pulse, with a standard uncertainty of 2.4%. In contrast, the k_s values determined using the IAEA and AAPM methods are, respectively, 8.9% and 8.2% higher than our results. Conclusions: The new method based on Boag's improved model provides a practical method of determining the ion-recombination correction factors for high dose-per-pulse radiation beams up to about 120 mGy/pulse. This method can be applied to electron beams with even higher dose-per-pulse, subject to independent verification.

• 융합신호처리학회논문지
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• 제22권4호
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• pp.213-219
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• 2021

잠수함의 방수펄스탐지는 적 수상함 및 잠수함, 어뢰 등에서 방사하는 펄스를 탐지하여 자함의 기동 및 생존성을 제공하는 중요한 기능을 수행한다. 방수펄스탐지 여부는 수신한 펄스의 크기와 운용자가 설정한 문턱값의 비교를 통해 결정된다. 방수펄스는 다양한 해양 환경요인의 영향으로 펄스의 세기가 작아지는 경우가 빈번하게 발생한다. 이런 상황에서 고정 문턱값으로 탐지를 수행할 경우 미탐지 문제가 발생되며 운용자가 낮은 문턱값을 설정하기 전까지 지속된다. 본 논문은 고정 문턱값으로 발생하는 미탐지 문제를 줄이기 위한 문턱값 자동 조절 방법을 제안하였다. 펄스 레벨 변동 폭이 다른 4가지 케이스로 시뮬레이션을 수행하였고 모든 케이스에서 문턱값 자동 조절 방법을 적용했을 때 탐지 개수가 증가하여 탐지 성능이 향상됨을 확인하였다. 제안한 방법을 통해 향후 펄스 레벨의 변동이 큰 해양환경에서 방수펄스탐지 성능 향상을 기대해본다.

• 한국의사학회지
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• 제26권2호
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• pp.63-74
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• 2013

Objective : In Donguibogam(東醫寶鑑), like a slow pulse with irregular intervals(結脈), an abrupt pulse(促脈) and a slow and weak pulse with regular intervals(代脈), an uneven pulse is written as a kind of arrhythmia. Such a recognition differs from the present one. In this study, I try to seize the meaning and deliberate whether those expressions are appropriate. Method : 1. Collect and compare the materials of the above four pulses among documentary records of feeling the pulse for diagnosis. 2. Grasp the aspect and trend of changes. 3. Reason whether records in Donguibogam(東醫寶鑑) are proper or not. Result & Conclusions : Donguibogam(東醫寶鑑) written "like a slow pulse with irregular intervals(結脈), an abrupt pulse(促脈) and a slow and weak pulse with regular intervals(代脈), an uneven pulse is written as a kind of arrhythmia". It is not 'an uneven pulse' is written about irregularity of pulse, but 'an uneven pulse' is written about irregularity of the sense able to be felt on the fingertip.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(5)
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• pp.17-20
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• 2000

Usually, in many applications, high frequency resonant inverters are used, and the PAM(Pulse Amplitude Modulation), PFM(Pulse Frequency Modulation) or PWM(Pulse Width Modulation) techniques are used to control the output power of resonant inverters. In this paper, a new switching scheme is proposed as a PWM control method. With the proposed method, it can be obtained that unity output displacement factor under the variable resonant frequency. The detail algorithm of the proposed PWM switching scheme and its charicteristics are discussed. And the validity of the proposed method is confirmed with the experimental results.

• 산업기술연구
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• 제27권B호
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• pp.15-20
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• 2007

This paper presents the new design method for the gate driver circuit of the floating MOSFET by using the pulse transformer. Each parameters of the proposed circuit are delivered by the numerical calculation method. By considering inner characteristics of MOSFET, the gate driver makes to increase the efficiency of the power conversion and decrease operating heat. Computer simulations and to experimental results for a Buck Converter are presented in order to validate the proposed method.

• Journal of Acupuncture Research
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• 제19권5호
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• pp.1-9
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• 2002

Objective : The study of relations between twelve meridians and pulse diagnosis Method : The possiblity of pulse diagnosis on the pulse points(脈動處) of each meridian through the scription of $\ll$Maek beop(脈法)$\gg$ $\ll$Nae kyeong(內經)$\gg$ and $\ll$Nan kyeong(難經$\gg$ Result : The comparative pulse diagnosis method(比較脈診法) in the scription of $\ll$Mack beop$\gg$ progressed to the five Jang bu maek(五臟脈) in the scription of $\ll$Young chu : Sa gi jang bu byeong hyeong(靈樞 邪氣臟腑病形)$\gg$ in accordance with the progress of pulse diagnosis and the theory of medicine. Conclusions : The comparative pulse diagnosis method in the scription of $\ll$Mack beop)$\gg$ progressed to the five Jang bu maek(五臟脈) in the scription of $\ll$Young chu : Sa gi jang bu byeong hyeong$\gg$ and the moxibustion and Pyum bup(貶法) in the scription of $\ll$Mack beop$\gg$ altered to acupuncture therapy on the five shu points(五輸穴)

• 한국전자파학회논문지
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• 제22권4호
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• pp.440-446
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• 2011

본 논문에서는 레이더 시스템에 적용이 가능한 50 W 출력을 가지는 X-대역 pulsed SSPA(Solid State Power Amplifier)를 설계 및 제작하였다. SSPA를 펄스 모드로 동작시키는 방법으로 펄스 변조 방법과 전원 스위칭 방법을 혼용한 방법을 제안하였다. SSPA는 구동 증폭기, 고출력 증폭기, 펄스 변조기로 구성되며, 충분한 이득과 출력 크기를 얻기 위해 25 W GaAs FET 4개를 병렬 구조로 구성하였다. 측정 결과 1.12 GHz 대역폭에서 출력 50 W, 이득 44.2 dB의 성능을 가졌다. 또한, pulse droop은 1 dB 이하로 설계 목표를 만족하였으며, 12.45 ns 이하의 상승/하강 시간을 가졌다. 제작된 X-대역 pulsed SSPA 크기는 $150{\times}105{\times}30\;mm^3$로 매우 작은 크기를 가졌다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.659-662
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• 1999

Ultrasonic pulse velocity method is employed for evaluation of crack depth in concrete structures. Due to the heterogeneous nature of concrete and the indirect transmission arrangement for the transit time measurement through the surface-opening cracks in concrete structures, ultrasonic pulse velocity has so many variations as crack depths and transmission lengths vary. In this study, ultrasonic pulse velocity method is investigated to evaluate the surface-opening crack depth of concrete slabs, reinforced concrete slabs, reinforced concrete flexural members. the resent study gives a modified method for deminishing errors in transit time measurements and show limitations to the evaluation of crack depth in reinforced concrete structures.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.683-685
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• 1999

As a method of obtaining pulse transfer function. transfer function of discrete-time from input-output data, there are method of obtaining unknown parameter of pulse transfer function from estimated impulse response before(1-3). There is no need to approximate to several meanings because of not being established algebraical relations between impulse response for estimation error and parameter of transfer function exactly. In this paper, I inquire the method[4] of obtaining the optimal pulse transfer function as a meaning of Hankel norm approximation from impulse response data and examine estimated property as computer simulation from this method.

• 대한전자공학회논문지
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• 제24권4호
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• pp.658-666
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• 1987

In this paper, a new mehtod of reducing harmonics that involved in input AC line currents or in output DC voltage of the converter system is presented. which is due mainly to the quipment of 2-3 switching taps on interphase reactor. In case that the 3 tap method is applicable to conventional 12 pulse converter, it could not bring to an effect of reducing harmonics under firing angle 15\ulcorner To solve these problems, 24 pulse or 36 pulse converter is controlled by microprocessor. The former is performed in 2 tap method when \ulcorneris less than 15\ulcorner the latter in 3 tap method when it is more then 15\ulcorner Therefore the originality of this paper liea in microprocessor based equipment of the 2-3 switching taps on interphase reactor. I applied this method to the 12 pulse converter, and proved validity of that theoretically and experimentally.