Generation of Klobuchar Ionospheric Error Model Coefficients Using Fourier Series and Accuracy Analysis

이창문,박관동 한국우주과학회 2011 Journal of Astronomy and Space Sciences Vol.28 No.1

Ionospheric error modeling is necessary to create reliable global navigation satellite system (GNSS) signals using a GNSS simulator. In this paper we developed algorithms to generate Klobuchar coefficients α_n, β_n (n = 1, 2, 3, 4) for a GNSS simulator and verified accuracy of the algorithm. The eight Klobuchar coefficients were extracted from three years of global positioning system broadcast (BRDC) messages provided by International GNSS service from 2006 through 2008and were fitted with Fourier series. The generated coefficients from our developed algorithms are referred to as Fourier Klobuchar model (FOKM) coefficients, while those coefficients from BRDC massages are named as BRDC coefficients. The correlation coefficient values between FOKM and BRDC were higher than 0.97. We estimated total electron content using the Klobuchar model with FOKM coefficients and compared the result with that from the BRDC model. As a result,the maximum root mean square was 1.6 total electron content unit.

DCB 적용 한반도 전리층 격자 모델 개발

이창문,김지혜,박관동 한국우주과학회 2011 한국우주과학회보 Vol.20 No.1

이 연구에서는 한반도 상공의 전리층 총전자수를 격자 형태로 나타냈다. 이를 위해 국토해양부 GPS 상시관측소에서 제공 중인 코드와 위상 측정값을 선형조합하였으며 그 결과물을 이용하여 시선방향 총전자수를 산출하였다. 이때 전리층 총전자수 산출 결과의 정확도를 향상시키기 위해 가중최소자승법을 이용하여 위성과 수신기의 하드웨어 오차인 DCB(Differencial Code Bias)를 추정하였으며 추정된 DCB값은 IGS에서 제공 중인 DCB값과 비교하여 정확도를 확인하였다. 산출된 시선방향 총전자수를 연직방향 총전자수로 변환하기 위해 사상함수를 적용하였으며, 이를 다시 각 격자점에서의 연직방향 총전자수로 변환하기 위해 기존 연직방향 총전자수에 역거리 가중 보간법을 적용하였다. 각 격자점에서의 총전자수는 IGS(International GNSS Service)에서 제공 중인 GIM(Global Ionosphere Map) 모델의 총전자수와 비교하여 정확도를 확인하였다. 산출된 총전자수는 2시간 간격으로 나타내어 한반도 상공 전리층 총전자수의 변화 경향을 확인하였다.

외부교육 환경변화에 따른 대학자산 활용의 효율적 제안

이창문,박태원 한국지역개발학회 2019 한국지역개발학회 학술대회 Vol.2019 No.5

The purpose of this study is to analyze the development cases of basic property for education and basic property for profit in order to expand the finances of increasingly poor private universities and to present policy implications for profit models. A decade-long freeze on tuition fees, phased abolition of admission fees, a decline in enrollment quota, and donations driven by several specific universities and poor state subsidies are making many private universities" finances even worse. Due to the decrease in enrollment quota, the basic property for education exceeding the standard of securing will continue to increase, and universities are developing or selling the basic property for excess education by converting it into basic property for profit, or introducing commercial facilities into basic property for education. In addition, universities that dispose of low-return basic property, acquire high-return basic property alternatively, or own land and buildings in central commercial areas purchase additional land adjacent to the existing site and develop it in scale. To this end, the management"s firm will and execution, the recruitment of professionals to strengthen expertise should precede them first, and the development of basic assets for education and profits will likely further expand for such universities to expand their finances.

1LC-6 Melanin-based therapeutic agents for photothermal therapy

이창문,김민아,윤순도 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

Photothermal therapeutic agents (PTAs) are used to help convert light to heat because of the low conversion efficiency of light energy into heat in living tissues. Melanin absorbs a large range of light from ultraviolet to near infrared (NIR) wavelengths. This presentation will discuss our recent approaches to melanin as a PTA for photothermal cancer therapy. First, we have prepared thermohydrogels containing melanin, showing sol-gel transition at body temperature. Secondly, we have prepared melanin-loaded liposomes for systemic injection. After irradiation of 808 nm NIR laser at 1.5 W/㎠ for 3 min, heat generation was enough to kill cancer cells in vitro and in vivo. The tumor growth of mice bearing CT26 tumors treated with the thermohydrogel or the liposomes is suppressed completely after laser irradiation. These results indicate that melanin can become an attractive PTA for photothermal cancer therapy.

제43차 대한핵의학회 추계학술대회 : 일반연제 ; 방사화학 : 쥐 염증 모델에서의 Tc-99m 표지 mannosylated PEG-liposome과 mannan-coated PEG-liposome의 감염병소에서 섭취비교

이창문,허영준,송호천,박지현,박정은,민정준,범희승,이기영 대한핵의학회 2004 핵의학 분자영상 Vol.38 No.5

Temperature-Induced Release of All-trans-Retinoic Acid Loaded in Solid Lipid Nanoparticles for Topical Delivery

이창문,정환정,박지원,김진,이기영 한국고분자학회 2008 Macromolecular Research Vol.16 No.8

The aim of this work was to develop and evaluate solid lipid nanoparticles (SLN) containing all-transretinoic acid (ATRA) for topical delivery. SLN composed of coconut oil and curdlan improved the suspension instability of ATRA in aqueous solution. The photodegradation of ATRA by light was reduced by incorporation in SLN. The loading efficiency of ATRA in SLN was higher than 95% (w/w). The amounts of ATRA released from SLN at 4 oC and at 37 oC were less than 15% and more than 60% (w/w) for 96 h, respectively. The ATRA-loaded SLN can be used as a potential carrier for topical delivery.

Generation of Klobuchar Coefficients for Ionospheric Error Simulation

이창문,박관동,이상욱,하지현 한국우주과학회 2010 Journal of Astronomy and Space Sciences Vol.27 No.2

An ionospheric error simulation is needed for creating precise Global Positioning System (GPS) signal using GPS simulator. In this paper we developed Klobuchar coefficients n α and n β (n = 1, 2, 3, 4) generation algorithms for simulator and verified accuracy of the algorithm. The algorithm extract those Klobuchar coefficients from broadcast (BRDC) messages provided by International GNSS Service during three years from 2006 through 2008 and curve-fit them with sinusoidal and linear functions or constant. The generated coefficients from our developed algorithms are referred to as MODL coefficients, while those coefficients from BRDC messages are named as BRDC coefficients. The maximum correlation coefficient between MODL and BRDC coefficients was found for α 2 and the value was 0.94. On the other hand, the minimum correlation was 0.64 for the case of 1 α. We estimated vertical total electron content using the Klobuchar model with MODL coefficients, and compared the result with those from the BRDC model and global ionosphere maps. As a result, the maximum RMS was 3.92 and 7.90 TECU, respectively.

매체환경과 청소년 사이버비행과의 관계에 대한 연구 : 성인매체몰입을 중심으로

이창문,문진영,박주원 한국디지털정책학회 2019 디지털융복합연구 Vol.17 No.4

The purpose of this study is to investigate what factors affect cyber-delinquency after examining the previous research focusing on the general strain theory and the delinquency opportunity theory in the existing studies. And as adolescents move from middle school to high school, this study is intended to analyze what factors affect cyber-delinquency from a longitudinal perspective using KCYPS(Korea Child and Youth Panel Survey) elementary 4th grade fourth and seventh data. The adolescence cyber-delinquency probability of occurrence were analyzed through the panel logit fixed-effect model using STATA. And then the cyber-delinquency frequency of adolescents were analyzed through the panel tobit random-effect model. As a result of analyzing the factors affecting cyber-delinquency frequency, Adult media commitment, computer use time, and cell phone dependency increased cyber-delinquency frequency. On the other hand, among the parenting attitudes, the attitude of supervising attentively and adolescents’ age-increasing decreased cyber-delinquency frequency. 본 연구는 사이버 비행에 영향을 미치는 요인은 무엇인지를 살펴보기 위해 기존의 여러 연구에서 검토된 일반긴장 이론, 비행기회 이론을 중심으로 선행연구를 고찰한 이후 한국 아동·청소년 패널 초등학교 4학년을 대상으로 한 패널 4차 자료와 7차 자료를 이용하여 청소년이 중학교에서 고등학교로 이행하는 과정에서 사이버 비행에 영향을 주는 요인을 종단적 측면에서 분석하고자 하였다. 연구방법은 STATA 프로그램을 이용하여 사이버 비행을 저지르는 결정요인을 패널 로짓분석을 통해 살펴본 다음 이후 패널 토빗확률효과 모형을 통하여 청소년의 사이버 비행횟수에 영향을 주는 요인들에 대해 분석하였다. 분석결과, 사이버 비행횟수와 관련해서는 성인매체몰입, 컴퓨터 사용시간, 휴대폰 의존 정도는 사이버 비행횟수를 증가시켰으며, 연령증가, 부모의 양육태도 중 관심적 감독은 청소년의 사이버 비행횟수를 감소시키는 것으로 나타났다

In vivo VEGF receptor 2-targeted imaging using TTAC-combined SPIO nanocrystals

이창문,김세림,김은미,정수진,유진산,김동욱,정환정,임석태,손명희 대한핵의학회 2007 핵의학 분자영상 Vol.41 No.5

Synthesis and Characterization of Iron Oxide Nanoparticles Decorated with Carboxymethyl Curdlan

이창문,김은미,정수진,박은혜,김동욱,임석태,손명희,정환정 한국고분자학회 2009 Macromolecular Research Vol.17 No.2