• Progress in Medical Physics
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• v.10 no.3
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• pp.133-140
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• 1999

In this paper, as a preliminary study for developing a full 3D electron dose calculation algorithm, We developed 2.5D electron dose calculation algorithm by extending 2D pencil-beam model to consider three dimensional geometry such as air-gap and obliquity appropriately. The dose calculation algorithm was implemented using the IDL5.2(Research Systems Inc., USA), For calculation of the Hogstrom's pencil-beam algorithm, the measured data of the central-axis depth-dose for 12 MeV(Siemens M6740) and the linear stopping power and the linear scattering power of water and air from ICRU report 35 was used. To evaluate the accuracy of the implemented program, we compared the calculated dose distribution with the film measurements in the three situations; the normal incident beam, the 45$^{\circ}$ oblique incident beam, and the beam incident on the pit-shaped phantom. As results, about 120 seconds had been required on the PC (Pentium III 450MHz) to calculate dose distribution of a single beam. It needs some optimizing methods to speed up the dose calculation. For the accuracy of dose calculation, in the case of the normal incident beam of the regular and irregular shaped field, at the rapid dose gradient region of penumbra, the errors were within $\pm$3 mm and the dose profiles were agreed within 5%. However, the discrepancy between the calculation and the measurement were about 10% for the oblique incident beam and the beam incident on the pit-shaped phantom. In conclusions, we expended 2D pencil-beam algorithm to take into account the three dimensional geometry of the patient. And also, as well as the dose calculation of irregular field, the irregular shaped body contour and the air-gap could be considered appropriately in the implemented program. In the near future, the more accurate algorithm will be implemented considering inhomogeneity correction using CT, and at that time, the program can be used as a tool for educational and research purpose. This study was supported by a grant (＃HMP-98-G-1-016) of the HAN(Highly Advanced National) Project, Ministry of Health & Welfare, R.O.K.

• The Korean Journal of Applied Statistics
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• v.18 no.2
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• pp.271-280
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• 2005

Kriging methods as traditional spatial data analysis methods and geographical weighted regression models as statistical analysis methods are compared. In this paper, we apply data from the Ministry of Environment to spatial analysis for practical study. We compare these methods to performance with monthly carbon monoxide observations taken at 116 measuring area of air pollution in 1999.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.83-87
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• 2009

Ramjet engine is weak for low frequency combustion instability because of their long air flow passage. A model combustor which has fuel injector and V-gutter shaped flame holder was designed and fabricated in order to simulate a combustion mechanism of ramjet engine, and it could demonstrate combustion instability which might occur in ramjet combustor. The frequency of the instability was very similar to that of acoustic resonance frequency of combustor, and it proved that a typical combustion instability by thermo-acoustic coupling occurred.

• Journal of the Korean Society for Railway
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• v.11 no.5
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• pp.482-488
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• 2008

Seoul Metro Line 9 (SML9) will link Gimpo Airport to the Gangnam district opening in May 2009. SML9 has a new model in Korea constructed by metropolitan government and private company and operated by specialized public transportation service provider. SML9 is confronted with tough environment of stagnated public transportation and strong competitor, Olympic city expressway. Consequently SML9 must lead the maximum efficiency by using its material and human resource. Hereupon, I propose renovation plans from 3 viewpoints of operation field of SML9: Rapid-Local combination, close connection with other transportation and direct connecting service into Incheon Air-port Railroad(AREX).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.624-626
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• 2022

It is possible to manage individual exercise information using a smartphone application that may be attached to exercise equipment. We propose a service platform that provides effective exercise techniques and management information to athletes by establishing an AI module to analyze and present the current user's exercise volume and exercise intensity direction through analysis of exercise data. To this end, it can be effectively managed by establishing a system based on a cloud environment and builds a hybrid health model that utilizes air and magnetic technologies at the same time.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.139-139
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• 2019

지구 온난화 및 기후변화로 인해 비롯된 전 지구적인 기온 상승은 가뭄, 폭염, 한파 등의 이상 기후 현상을 야기하여 인류의 생존을 위협하는 환경 문제로 대두되고 있다. 이와 같은 기후변화 및 이상기후 현상을 이해하고 파악하기 위해서는 정확하고 상세한 기온 정보가 필수적이다. 우리나라는 기상청에서 전국 590개소의 기상관측장비로 기온 정보를 생산하고 있지만 산림이 약 70%를 차지하는 복잡한 지형을 가지고 있어 지상관측밀도의 공간적 제약이 발생해 상세하고 균일한 기온 정보 생산에 제약이 있다. 이러한 단점을 극복하기 위해 본 연구에서는 위성으로 측정한 지표면 온도(Land Surface Temperature, LST) 자료와 다중선형회귀모형(Multiple Linear Regression Model)을 활용해 두 자료간의 상관관계를 파악하고 지상기온을 예측하고자 한다. 위성자료로 Terra 및 Aqua MODIS 위성의 1000m 공간해상도를 가진 일별 LST자료 MOD11A1, MYD11A1의 Daytime 자료를 각각 2000년부터 2018년까지 총 19년의 기간에 대해 구축하였으며, 전국 92개의 기상청 관측소로부터 최고, 최저 기온 자료를 동 기간에 대해 구축하였다. LST를 이용한 이상기온 예측 알고리즘은 python을 이용해 구현하였으며 예측 결과는 실제 기온 자료를 통해 검증하였다. 또한, 예측 기온 자료의 연대별, 순별(상, 중, 하순) 분석을 실시하고, 2018년 극한 폭염 및 한파(2017년 12월~2018년 2월)의 예측 가능성을 검토하여 연구 결과에 대한 다양한 활용방안을 제시하고자 한다.

• Clean Technology
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• v.17 no.1
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• pp.69-77
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• 2011

The intrinsic $CO_2$ separation and hydrogen production system is a novel concept using oxidation and reduction reactions of oxygen carrier for both $CO_2$ capture and high purity hydrogen production. The process consists of a fuel reactor (FR), a steam reactor (SR) and an air reactor (AR). The natural gas ($CH_4$) is oxidized to $CO_2$ and steam by the oxygen carrier in FR, whereas the steam is reduced to hydrogen by oxidation of the reduced oxygen carrier in SR. The oxygen carrier is fully oxidized by air in AR. In the present study, the chemical looping moving bed reactor having 200 L/h hydrogen production capacity is designed and the hydrodynamic properties were determined. Compared with other reactors, two moving bed reactors (FR, SR) were used to obtain high conversion and selectivity of the oxygen carrier. The desirable solid circulation rates are calculated to be in the range of $20{\sim}100kg/m^2s$ from the conceptual design. The solid circulation rate can be controlled by aeration in a loop-seal. To maintain the gas velocity in the moving beds (FR, SR) at the minimum fluidization velocity is found to be suitable for the stable operation. The solid holdup in moving beds decrease with increasing gas velocity and solid circulation rate.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.1
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• pp.213-220
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• 1993

The problem of disposing of huge quantities of used tires is of growing concern to every country. As an economical solid waste management, a gasification followed by incineration process was applied to scrap tires to recover heat and to reduce waste volume for final landfill disposal. The gasification temperature, combustible and non-combustible gasified products and possibly produced air pollutants were predicted by changing equivalent mole ratios of carbon to oxygen by a chemical equilibrium model. For a risk assessment of ash toxic pollutants including heavy metals and toxic organics were thoroughly analyzed. Gasification bottom ash contained much more toxic organic compounds than fly ash, whereas fly ash contained higher concentration of heavy metals such as Pb and Cd. Pretreatment or secure landfill technology is suggested for a safe management of ash produced from the gasification incinerators.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.6
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• pp.15-25
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• 2011

One dimensional combustion modeling of aluminum combustion behavior is proposed. Combustion model is assumed that region consists as follows ; preheat, reaction, post reaction region. Flame speed as a function of particle size, equivalence ratio for unitary particles and fraction ratio of micro to nano particle size for binary particles were investigated for lean burn condition at 1 atm. Results were compared with experimental data. For unitary particles, flame speed increase as particle size decreases, but opposite trend with equivalence ratio. For binary particles, flame speed increases proportionally as nano particle fraction increases. For flame structure, separated or overlapping flames are observed, depending on the fraction of nano sized particles.

• Korean Institute of Interior Design Journal
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• v.15 no.3 s.56
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• pp.48-55
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• 2006

A sustainable building must produce an interior environment that is safe, healthy, comfortable and supportive of human performance and well-being. The medical human comfort: performance and productivity cost of unhealthy environment may cause much cost for healing. Research that buildings with daylight, fresh air, eco-materials and sustainable interior design are consistently rated as more comfortable and occupants performance, satisfaction and health. This study is to categorize systematically interior environmental design elements for improving sustainability with a view to developing an evaluation model of super high-rise apartment unit plans. With a literature survey and design guide lines concerning sustainable design elements, three hierarchical categorization levels of human, environment, energy and resources systems that consists of upper, middle, low design elements have been proposed. A total of 6 items have been suggested for middle level of categorization and 24 items for lower level. Finally a total of 107 design elements concerning the 24 items and their relationahips have been revealed. The needs for a systematic approach to interior environmental design for sustainability have been discussed.