• Progress in Medical Physics
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• v.10 no.3
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• pp.151-157
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• 1999

The GafChromic film was used for the dosimetry of a balloon angio catheter filled with the radioisotope HO-166 for endovascular irradiation. The balloon angio catheter was 2 cm long and 3 mm in diameter when inflated. The isotope, Ho-166, was produced by the neutron bombardment using the research reactor in Korea Atomic Energy Research Insititute. Co-60 teletherapy beam was used for making H-D curve for the Gaf-Chromic film. The film dosimetry was measured with a videodensitometer. The radial dose distribution indicated that the absorbed dose dropped to about 20% of the surface dose at the 1 mm away from the balloon surface and at 5 mm position the dose decreased to below 1% of the surface dose. The result also shows that with the specific activity of Ho-l66, 250 mCi/ml it takes 230 seconds to deliver 1200 cGy to the region where is 1mm away from the balloon surface. The concentric isodose curves were also presented. The Ho-166 is an another alternative for endovascualr irradiation to prevent restenosis after PTCA (Percutaneous Trans Coronary Angioplasty)

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.1
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• pp.5-13
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• 2003

The purpose of this study is to determine the value of serum concentration of C-reactive protein(CRP) in comparison with ESR and leukocyte as the tools for diagnosis and follow-up study of infection. For this study, thirty-one patients with head and neck infection and thirty-two patients performed the orthognathic surgery were selected for experimental and control groups each other. we analyzed the blood sample daily to measure CRP, ESR and leukocytosis. The results of this study are as the following : 1. Serum C-Reactive Protein levels in the experimental group were higher than control group and the pattern of CRP changes continued to decline in both groups(P<0.001). 2. ESR changes in both groups were scattered without any special pattern. 3. Correlation between CRP and Leukocyte was higher than others(r=0.664, P<0.01). 4. In the Receiver Operating Characteristic(ROC) Curve of experimental group, rapid increase of CRP curve and Area under the curve(AUC) value, 0.774, indicate the high accuracy of estimation. 5. In experimental group, sensitivity of CRP, ESR, and Leukocytosis on recovery day were 83%, 17% and 71%. Based on the results of this study, we could conclude that determination of CRP is more useful method to diagnosis and follow-up study of infection than other commonly used variables in oral and maxillofacial region.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.44-44
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• 1999

저진공(1 kPa~ 100 kPa)은 대기압 측정, 비행고도, 기체의 온도 측정, 질량의 부력 보정, 레이저의 굴절률 측정등에 사용되는 영역으로 과학적 중요성을 갖고 있다. 또한 대기압 이상의 압력 측정과 고진공 측정의 경계적 역할도 수행하고 있어 압력 표준기의 국제 비교에 필수적으로 권장되는 역역이다. 이 영역에 주로 사용되는 압력 표준기는 수은 압력계(Mercury manometer)와 분동식 압력계(Deadweight piston gauge or Pressure)가 있다. 이들은 이동이 불편하거나 불가능하므로 표준기의 국제 비교에 사용되는 전달 표준기로는 보다 이동이 간편한 탄성 압력계인 CDG(Capacitance diaphragm Gauge)가 있다. 이 게이지는 반도체 산업의 공정 제어용으로도 많이 사용되고 있다. 그러나 게이지와 함께 사용되는 컨트롤러의 부피가 크고 무거우며 영점 이동이 커서 측정때 마다 재조정하여야 하는 단점이 있다. 본 논문에서는 이 같은 단점을 극복하기 위해 수정빔 진동형 진공 센서를 잔달 표준기로 사용하는 것에 대한 연구를 수행하였다. 수정빔 진동형 압력 센서는 수정빔으 공진주파수가 스트레인에 비례하는 것을 이용하여 제작된 센서로 주로 대기압 이상의 고압 측정에 많이 사용되고 있다. 먼저 수정빔의 압력과 주파수간의 관계를 측정하고 또한 내장된 수정 온도센서의 공진 주파수를 측정하여 온도 보상을 위한 자료로 사용하였다. 규격에 나와 있는 수정빔의 기하학적 형상으로부터 거동에 관한 이론 모델식을 구하고 압력교정 자료로부터 얻어진 데이터를 이 식과 비교 분석하여 적합한 특성식과 인자를 구하였으며 게이지의 불확도를 추정하였다.모델은 길이가 유한한 0-차원 실린더 모델로 가정하였고, 이에 대한 기하학적 성질 및 열역학적 성질은 유효계수를 고려하여 산출하였다. 진공용기 이중 벽 내부로 흐르는 질소가스의 유량과 온도의 계산은 진공용기 내벽과 외벽을 각각 독립적인 열전달 요소로 가정하여 구성한 모델을 이용하였다. 전체 해석에서 각 열전달 요소의 비열 값은 온도에 따라 변화하는 비열의 특성을 반영하였으며. 진공용기와 플라즈마 대향 부품의 방사율(emissivity)은 앞서 가정했던 각 온도 상승 곡선에 대해서 각각 0.1, 0.2, 1.3의 경우를 가정하여 계산하였다. 직선적으로 증가하는 온도 상승 곡선중 2$0^{\circ}C$/hr의 온도상승율을 갖는 경우가 다른 베이킹 시나리오 모델에 비해 효과적이라 생각되며 초대 필요 공급열량은 200kW 정도로 산출되었다. 실질적인 수치를 얻기 위해 보다 고차원 모델로의 해석이 필요하리라 생각된다. 끝으로 장기적인 관점에서 KSTAR 장치의 베이킹 계획도 살펴본다.습파라미터와 더불어, 본 연구에서 새롭게 제시된 주기분할층의 파라미터들이 모형의 학습성과를 높이기 위해 함께 고려된다. 한편, 이러한 학습과정에서 추가적으로 고려해야 할 파라미터 갯수가 증가함에 따라서, 본 모델의 학습성과가 local minimum에 빠지는 문제점이 발생될 수 있다. 즉, 웨이블릿분석과 인공신경망모형을 모두 전역적으로 최적화시켜야 하는 문제가 발생한다. 본 연구에서는 이 문제를 해결하기 위해서, 최근 local minimum의 가능성을 최소화하여 전역적인 학습성과를 높여 주는 인공지능기법으로서 유전자알고리즘기법을 본 연구이 통합모델에 반영하였다. 이에 대한 실

• Journal of Wetlands Research
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• v.12 no.1
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• pp.95-103
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• 2010

Discharge data examine the process of hydrologic cycle and used significantly in water resource planning and irrigation and flood control planning. However, it needs lots of time and money to get the discharge data. So discharge rating curve is usually used in converting discharge data. Therefore reliability of discharge rating curve absolutely depends on quality of discharge data. Many engineers who study hydrologic engineering make high quality discharge data to develop reliable discharge rating curve. And they carry out research on standard and method of discharge measurement, and equipment improvement. Now various flow meters are utilized to make discharge data in Korea. However, accuracy of equipment and experimental research data from measurement are not enough. In this paper, constant discharge flowed through standard concrete channel, and the velocity is measured using various flow meters. Also Discharge is calculated by measured data to compare and analyze. The equipment for the experiment is Price AA(USGS Type AA Current meter), flow meter, ADC, C2 small current meter, flow tracker, Electromagnetic current meter. The discharge got form various flow meters which are widely used for discharge measurement. The various depths of water were examined and compared such as 0.30 m, 0.35 m, 0.40 m, 0.45 m, 0.50 m, 0.55 m. The experiment progresses a round-measurement on 6-case. Wading measurement(one point method : the 60 % height in surface of the water) was applied to improve creditability and accuracy among measurement methods. USGS Type AA current Meter, Flow Meter, ADC, C2 Small Current meter got the certificate of quality guaranteed. So the results of experiment were used to compare discharge. The Results showed the difference based on USGS Type AA current Meter at average discharge and velocity. Electromagnetic current meter made differences over $\pm$ 10 % and Flow Meter made differences under $\pm$ 10 %. Also ADC, Flow Meter, C2 Small Current meter made differences under $\pm$ 5 %.

• Progress in Medical Physics
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• v.6 no.2
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• pp.35-40
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• 1995

Purpose: We have developed new film dosimetry algorithm for personal dosimetry and examined its characteristics. Materials and methods: Agfagaevart personal monitoring 2/10 films are used. Films which are in the film badges filtered with Cu 0.3mm, plastic 1.5mm, Aluminum 0.6mm and tin 0.8mm, were exposed by standard dosimetry laboratory. Irradiated energy categories are ANSI N13.1l Category III, and IV. Manual type film precessor and X-rite film densitometor was used. Filtered densities to energy relations and does to transformed densities relations can be obtained ofter transformation of H＆D curves to linear shape by polynomal fitting. Reults : Personal dose be determined within 25％ error for category m and 15％ for category IV. And we are able to evaluate the exposed energy. Conclusion : New algorithm developed in this study is good for personal dosimetry within 30％ error range for catergory III and IV. It is expectd to be complete personal dosimetry algorithm with further study for categrory, I, Dand II V.

• Nuclear Engineering and Technology
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• v.6 no.4
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• pp.219-230
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• 1974

The previous expression for the diffracted neutron intensity by a highly oriented polycrystalline is modified using the Kunitomi's formula of the crystal reflectivity The method of studying the preferred orientation in metals with white neutron is proposed utilizing the above formula and the fact that the real position of the diffraction of certain grain in the sample can be found by the comparison of the smaller angle part of the maxwellian curve of the calculated intensity of neutrons diffracted and the experimenal curves. The most probable wavelength of thermal neutrons from the reactor is found by the measurement of the neutron spectrum with the correction for the crystal about the multiple reflection and the absorption of neutrons and turned out to be 1.025 $\pm$ 0.001$\AA$. The preferred orientations of some electric steel sheets, mostly with the cube-on-face orientations, are investigated by the present method. The orientations of most grains relative to the rolling directions are found to be within 5 degrees. It is found the most of theories for large crystals may be extended to highly oriented polycrystalline materials without extensive modification.

• Journal of the Korean Institute of Gas
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• v.2 no.1
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• pp.1-6
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• 1998

A low power (below than 300 mW) catalytic bead combusible gas sensor is developed and utilized with a computer controlled sampling system for measuring heat content of natural gas. The heat content of gas is proportional to the change in the energy required to exposure to the sample of combustible gas. The heat content of natural gas samples ranging 36.30 - 39.88 $MJ/m^3$ is measured in the range of approximately $1\%$ error, which is comparable to its nominal heat content. Each gas represents a slightly different curve of sensitivity to sensor temperature. Thus all of the sensitivities are not equal to every temperature. In calibration process the choice of a optimum operating temperature is an important factor that influences the overall performance of the measurement system.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.3
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• pp.440-449
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• 1988

Small vibration displacements may be measured by optical interferometers, based on the Michelson method. The standard Michelson interferometer works well when the mirror displacements are relatively large compared to the optical wavelength. But it does not work for displacements less than approximately a quater of optical wavelength. Several multiple reflection laser interferometers, simply modified standard Michelson interferometer, have been developed to decrease the minimum detectable limits. Among these a relatively simple and easy multiple reflection system is used to measure the small vibration displacements. This multiple reflection system is constructed with a right angle prism and a convex lens. Therefore this system makes it possible to measure a vibration displacement of the small area on the vibrating structure. The fringe interpolation method and curve fitting method are used to determine accurately the small vibration displacements from the measured interference fringe patterns. Also computer simulation technique is used to check the accuracies of these method. According to the results of the computer simulation technique, the curve fitting method is more accurate than the fringe interpolation method. The optically measured results are in good agreement with those of the standard accelerometer with high accuracy and it is possible to measure the peak vibration displacement as small as 9.01nm using multiple reflection system and curve fitting method.

• Journal of Korean Society of Transportation
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• v.25 no.2 s.95
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• pp.7-15
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• 2007

The accuracy of a Video Image Detector (VID) is gradually reduced due to various environmental and mechanical factors. However, there has been no systematic research about the decrease of VID accuracy. To maintain a proper level of VID accuracy for advanced traffic management, a regular VID calibration process needs to be introduced. However, the calibration cannot be performed frequently because of the cost. In this study, the researchers collected field data for accuracy estimation and inferred an accuracy decreasing function by using regression and considering the heteroscedasticity problem. Using the invented data collection equipment which was used for checking adaptability, some data in the field were collected and analyzed. Although the data were limited, the results are promising. More data need to be investigated in the future and this study will help to maintain the data quality for broad utilization of the data in ITS centers.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.285-289
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• 2017

Laser-induced breakdown spesctroscopy (LIBS) is a technique that complements the disadvantages of conventional laser-based combustion diagnosis techniques such as weak signal strength, complex equipment configuration, and low accuracy. In this study, basic research was carried out to measure the combustion gas temperature of scramjet engines using LIBS. Spray flames were generated from Jet A-1 fuel used in scramjet engines and gas temperatures were measured at the top of the flames with a calibrated thermocouple. The LIBS signals were acquired at the same points as the temperature measurement positions of the thermocouple. The LIBS spectra were analyzed to obtained a calibration curve between the LIBS signal and the reference temperature measured at the thermocouple. Therefore, it was confirmed that the combustion gas temperature can be measured in-situ using LIBS.