• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2003년도 제27회 추계학술대회
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• pp.64-64
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• 2003

Objectives: Patient dose verification is clinically the most important parts in the treatment delivery of radiation therapy. The three dimensional(3D) reconstruction of dose distribution delivered to target volume helps to verify patient dose and determine the physical characteristics of beams used in intensity modulated radiation therapy(IMRT). We present Beam Intensity Scanner(BInS) system for the pre treatment dosimetric verification of two dimensional photon intensity. The BInS is a radiation detector with a custom made software for relative dose conversion of fluorescence signals from scintillator. Methods: This scintillator is fabricated by phosphor Gadolinium Oxysulphide and is used to produce fluorescence from the irradiation of 6MV photons on a Varian Clinac 21EX. The digitized fluoroscopic signals obtained by digital video camera will be processed by our custom made software to reproduce 3D relative dose distribution. For the intensity modulated beam(IMB), the BInS calculates absorbed dose in absolute beam fluence, which are used for the patient dose distribution. Results: Using BInS, we performed various measurements related to IMRT and found the followings: (1) The 3D dose profiles of the IMBs measured by the BInS demonstrate good agreement with radiographic film, pin type ionization chamber and Monte Carlo simulation. (2) The delivered beam intensity is altered by the mechanical and dosimetric properties of the collimating of dynamic and/or static MLC system. This is mostly due to leaf transmission, leaf penumbra, scattered photons from the round edges of leaves, and geometry of leaf. (3) The delivered dose depends on the operational detail of how to make multileaf opening. Conclusions: These phenomena result in a fluence distribution that can be substantially different from the initial and calculative intensity modulation and therefore, should be taken into account by the treatment planing for accurate dose calculations delivered to the target volume in IMRT.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 추계학술대회 논문집
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• pp.357-362
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• 1993

In this study low priced laser measurement system was made, so its reliability was investigated Intensity distribution of laser beam measured by devised system and FFT analyzer and their results were examined for proving reliability of devised system. Transmitted laser beam intensity on photodiode changed by eccentrically rotating of disk cam and motor speed. To get results, photodiode and devised amplifier were used for changing voltage. After that, response signal was calculated by signal analysis program. It was found that the vibration of disk cam could be measured by the intensity distribution of laser beam and the same tendency was obtained by FFT. Change of motor speed effected the distribution of laser beam,which was obtained by devised system. Also linear distribution was got by sensitive balancing switch on amplifier according to the transmission of laser beam on photodide.

• Journal of the Korean Data and Information Science Society
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• 제9권2호
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• pp.305-310
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• 1998

In this paper, we introduce the conditions that the P-process has the intensity function which it is a standard form of gamma distribution. And we show that the transformed geometric Poisson process which the intensity function is a standard form of gamma distribution is a alternative sign P-process

• 조명전기설비학회논문지
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• 제13권3호
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• pp.1-6
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• 1999

형광등용 조명기구에 사용되는 경명 반사판의 광학 설계 프로그램을 개발하였다. 이 프로그램은 조명기구 설계시간을 단축시킨다. SpeROD(Specular Reflector Optical Designer)는 2차원적인 조건들을 가지고 계산한다. 반사판 설계를 위해 고려되는 조건들은 목표배광, 반사판 그리고 Tangent Spiral Design 방법등이 있다. 본 논문에서는 SpeROD를 이용하여 지름 26mm(T8)의 형광램프와 폭 150mm의 반사판을 가지는 균일 배광 형태와 Bat-wing 배광형태의 반사판을 설계해보았다. 설계된 반사판의 형태에 대하여 배광에측 프로그램인 FIELD를 통하여 배광을 시뮬레이션 해 본 결과, 배광과 효율 면에서 만족스러운 결과를 얻었다.

• 조명전기설비학회논문지
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• 제25권12호
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• pp.60-66
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• 2011

There are several technological problems have to be resolved for LEDs to be used as a general purpose light source. In addition, there are several differences between existing luminaires and the general planer LED luminaire for the intensity distribution. Therefore, the optical engineer then faces the challenging a problem of designing for a spatially extended and non-uniform light source. In the previous studies on the optical design of luminaires, a lot of studies on reflectors and light source have been conducted but the ones on prisms and lenses are insufficient at present. This study developed the numerical model of planar prism LED luminaire to control luminous intensity distribution of LED luminaires. And this study presents an optical calculation process for the prism optical design of a planar prism LED luminaire and a comparison of the simulation results between the developed numerical model and Photopia 2.0 to verify the accuracy of the numerical model. In addition, this study showed a method for the control of various luminous intensity distribution from the developed numerical model.

• 한국통신학회논문지
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• 제37권8A호
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• pp.698-705
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• 2012

무안경 방식 스테레오스코픽 입체 디스플레이 시스템에서 시역간 크로스토크는 입체시를 저해하는 주요 문제이다. 기존 크로스토크에 대한 연구는 관찰자면에서 수평 방향으로 인접한 시역간 겹침비를 정량적으로 분석하는 것이 대부분이었으나, 본 연구에서는 이를 포함, 깊이 방향으로 형성되는 해당시점영상의 밝기분포를 정량화하여 수평, 깊이방향에 따른 유효 관찰영역을 제시함으로서 효과적인 입체시 시청 범위를 제공하는데 목적을 두었다. 본 논문에서는 무안경방식의 스테레오스코픽 입체 디스플레이 환경에서 유발되는 크로스토크의 주요 인자들을 디스플레이 환경 및 관찰환경에서 도출하고 이들의 관계를 정성적으로 분석할 수 있는 알고리듬 개발 및 이를 가시화 할 수 있는 시뮬레이션 툴을 제작하였다. 더불어 시뮬레이션 결과를 응용하여 관찰자를 최적의 입체시 시청영역으로 유도 할 수 있는 최적입체시 가이드 시스템을 제안하였다.

• 유통과학연구
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• 제13권6호
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• pp.35-44
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• 2015

Purpose - To accelerate economic cooperation, this study investigates trade structures of Korea and the United States and identifies trade discrepancies. Such discoveries can lead to increases in trade volume by improving policies, eventually uncovering ways for trade expansion. Research design, data, and methodology - The Index of trade intensity, from trade intensity theory, is used to analyze the trade decision factors. Even though specific factors should materialize in the analysis, realistically, concrete explanations are difficult as there are so many unsolved factors and diversifications. Results - First, the Index of A value/ B value positions Korean against the United States in terms of market share and Korea against world market share, which thereby reveals comparative market intensity. Second, Korea is taking comparative advantage of export specialization. Third, real comparative advantage indices are considerably improved since early 2000. Conclusions - This study uses quantitative measurements and trade intensity theory and trade specialization to come up with a comparative advantage index to see how inter-trade relations between Korea and the United States have changed over the past 10 years.

• Wind and Structures
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• 제38권4호
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• pp.309-323
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• 2024

The gust factor and turbulence intensity are two crucial parameters that characterize the properties of turbulence. In tropical cyclones (TCs), these parameters exhibit significant variability, yet there is a lack of established formulas to account for their probabilistic characteristics with consideration of their inherent connection. On this condition, a probabilistic analysis of gust factors and turbulence intensities of TCs is conducted based on fourteen sets of wind data collected at the Sutong Cable-stayed Bridge site. Initially, the turbulence intensities and gust factors of recorded data are computed, followed by an analysis of their probability densities across different ranges categorized by mean wind speed. The Gaussian, lognormal, and generalized extreme value (GEV) distributions are employed to fit the measured probability densities, with subsequent evaluation of their effectiveness. The Gumbel distribution, which is a specific instance of the GEV distribution, has been identified as an optimal choice for probabilistic characterizations of turbulence intensity and gust factor in TCs. The corresponding empirical models are then established through curve fitting. By utilizing the Gumbel distribution as a template, the nexus between the probability density functions of turbulence intensity and gust factor is built, leading to the development of a generalized probabilistic model that statistically describe turbulence intensity and gust factor in TCs. Finally, these empirical models are validated using measured data and compared with suggestions recommended by specifications.

• 한국생산제조학회지
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• 제23권6호
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• pp.609-617
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• 2014

We have studied a chip-on-board LED lighting optical system for various luminous-intensity-distribution angles of the LED. An optical system that can accept different LEDs was made to reduce the systems's weight and size as we selected the chip-on-board LED, which is easy to apply to optical systems, unlike existing package-on-board LEDs. The luminous-intensity-distribution angles were $45^{\circ}$, $60^{\circ}$, $90^{\circ}$, and $120^{\circ}$. We researched these four types of optical systems. The $45^{\circ}$ and $60^{\circ}$ units were developed into reflectors, and the $90^{\circ}$ and $120^{\circ}$ units, into lenses. We checked the performance of the designed optical system through simulation and made a mock-up. Then we made a prototype of the chip-on-board LED high bay for use with the mock-up. After measuring its performance, we tested the luminous-intensity-distribution angles and compared them with simulation data. The resulting prototype was developed considering brightness, light uniformity, age, and economics which are suitable for a factory environment.

• 대한기계학회논문집A
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• 제22권4호
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• pp.953-959
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• 1998

To investigate accuracy of intensity method for measurement of the fiber orientation distribution, fiber orientation function is calculated by drawing simulation figures for the fiber orientation as varying fiber aspect ratio, fiber area ratio, and fiber orientation state, respectively. The values of fiber orientation function measured by intensity method are compared with the calculated values of fiber orientation function. The results show that measurement accuracy of the fiber orientation angle distribution by intensity method is affected by the fiber aspect ratio when the total length of oriented fiber is same. The average gradient of fiber orientation function is 0.94 for 1000mm of the total fiber length and is 0.93 for 2000 mm when the fiber aspect ratio is over 50. Measurement accuracy by intensity method is about 94% and the reliable data can be obtained by intensity method.