Downscaling of AMSR-E soil moisture with MODIS products using machine learning approaches

Im, Jungho,Park, Seonyoung,Rhee, Jinyoung,Baik, Jongjin,Choi, Minha Springer-Verlag 2016 Environmental Earth Sciences Vol.75 No.15

<P>Passive microwave remotely sensed soil moisture products, such as Advanced Microwave Scanning Radiometer on the Earth Observing System (AMSR-E) data, have been routinely used to monitor global soil moisture patterns. However, they are often limited in their ability to provide reliable spatial distribution data for soil moisture due to their coarse spatial resolutions. In this study, three machine learning approaches-random forest, boosted regression trees, and Cubist-were examined for the downscaling of AMSR-E soil moisture (25 9 25 km) data over two regions (South Korea and Australia) with different climatic characteristics using moderate resolution imaging spectroradiometer products (1 km), including surface albedo, land surface temperature (LST), Normalized Difference Vegetation Index, Enhanced Vegetation Index, Leaf Area Index, and evapotranspiration (ET). Results showed that the random forest approach was superior to the other machine learning models for downscaling AMSR-E soil moisture data in terms of the correlation coefficient [r = 0.71/0.84 (South Korea/Australia) for random forest, 0.75/0.77 for boosted regression trees, and 0.70/0.61 for Cubist] and root-mean-square error (RMSE = 0.049/0.057, 0.052/0.078, and 0.051/0.063, respectively) through cross-validation. The ET and LST were identified as the most influential among the six input parameters when estimating AMSR-E soil moisture for South Korea, while ET, albedo, and LST were very useful for Australia. In overall, the downscaled soil moisture with 1 km resolution yielded a higher correlation with in situ observations than the original AMSR-E soil moisture data. The latter appeared higher than the downscaled data in forested areas, possibly due to the overestimation of soil moisture by passive microwave sensors over forests, which implies that downscaling can mitigate such overestimation of soil moisture.</P>

항공라이다를 활용한 개체목 수관추출 방법 개발

임정호(Im, Jungho),Tao Liu,Fang Fang,이정희(Lee, Junghee),김경민(Kim, Kyungmin),김은숙(Kim, Eunsook) 한국측량학회 2013 한국측량학회 학술대회자료집 Vol.2013 No.4

전천에서의 위성-모델 융합 에어로졸 광학두께 추정

임정호(Jungho Im),이정희(Junghee Lee),박서희(Seohui Park),신민소(Minso Shin),김미애(Miae Kim) 대한공간정보학회 2018 한국지형공간정보학회 학술대회 Vol.2018 No.11

A robust transparent protective hard-coating material using physicochemically-incorporated silica nanoparticles and organosiloxanes

Im, Hyeon-Gyun,Park, Go Un,Park, Hoy Yul,Jin, Jungho,Kang, Dong Jun Elsevier 2017 Progress in organic coatings Vol.105 No.-

<P><B>Abstract</B></P> <P>Here, we report on the synthesis of a silica nanoparticle (NP)-reinforced oligosiloxane nanohybrid material (SM-nanocomposite) and demonstrate its properties as a robust transparent hard coating material for various applications. The oligosiloxane (MMO) resin as a matrix was synthesized using methyl and methacryl silanes <I>via</I> a hydrolytic sol-gel condensation. The silica NPs with various sizes (12, 20 and 60nm) as nanofillers were also synthesized through a hydrolytic sol-gel condensation, and the surface of NPs was organically modified with methyl and methacryl functions, which allowed stable dispersion and chemical cross-linking of the NPs with MMO matrix. In this work, we introduce synthetic steps of the nanocomposite and discuss the optical, morphological, thermal and mechanical properties of the composite.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Synthesis of a silica nanoparticle (SNP)-embedded oligosiloxane nanohybrid material. </LI> <LI> Demonstration of high performance transparent protective hard-coating materials. </LI> <LI> Chemical modification of SNP redered homogeneous dispersion. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Public Officials’ Trust in Other Agencies and Citizens

Jungho Park(박정호),Seyeong Cha(차세영),Tobin Im(임도빈) 서울행정학회 2014 한국사회와 행정연구 Vol.24 No.4

신뢰는 사회과학 분야에서 엄청난 관심을 받고 있는 개념이면서 동시에 너무 많은 정의와 용례들로 그 이해에 혼란을 겪기도 한다. 많은 행위자가 참여하는 네트워크 형태로 공공서비스가 전달되는 현대사회에서 신뢰(trust)는 중요한 사회적 자본이자 도구로 인식되고 있으나, 공무원들이 다른 행위자들에게 갖는 신뢰는 그 개념이나 선행요인 등에 대한 관심은 부족하다고 할 수 있다. 본 연구는 공무원들이 다른 행위자들, 특히 상위기관의 공무원들과 일반 시민들에 대해 갖는 신뢰가 어떻게 형성되는지에 관심을 가지고 이에 영향을 미치는 선행요인으로써의 커뮤니케이션의 효과를 살펴보고자 하였다. 2012년 지방공무원들을 대상으로 한 서베이 결과를 분석한 결과, 커뮤니케이션을 많이 할수록 상위기관의 공무원들과 일반 시민들에 대한 신뢰가 높아지는 것을 확인할 수 있었다. 상위 정부기관과 지방정부 공무원들 간의 신뢰가 커뮤니케이션에 의해 향상될 수 있다는 점은 다음과 같은 함의를 갖는다. 첫째, 상위기관과의 동등하지 않은 관계에 민감한 지방정부 공무원들이, 상위기관과의 접촉을 통해서 지방 정부 수준의 어려움들을 이해받고 있다고 여기면서 신뢰가 높아지는 것으로 보인다. 둘째, 또한 이러한 커뮤니케이션을 통한 신뢰 향상으로 중앙정부 시각에서 보는 지방정부의 역할과 책임에 대한 이해도가 높아지는 것을 기대할 수 있다. 또한 공무원들은 시민들의 능력에 대해 회의적이라는 기존의 연구결과를 고려할 때, 시민들과 접하는 빈도가 높아질수록 이들을 신뢰하게 되면서 시민 참여의 폭을 넓히는 데 일조할 수 있을 것이라는 함의도 도출할 수 있을 것으로 보인다. As the concept of trust becomes a full-fledged theme in various social sciences, confusion regarding its definition, dimensions, and usages has also surged. Despite the increasing attention paid to the importance of trust in public organizations for effective public-service delivery in the context of complex interplay of multiple agencies, relatively little attention has been paid to the conceptual components and antecedents of trust at the level of the public official. Bearing this point in mind, this research begins from a question about how public officials’ interactions with citizens and other agencies affect the level of trust at the individual level. Specifically, this research primarily aims to examine the effects of public officials’ communication with various type of actors and organizations on trust. For this purpose, this study employs ordinary least squares and random effect models in order to control unobserved effects resulting from the characteristics of 213 different offices at the local government level. The analysis indicates that the more opportunities that public officials have to communicate with citizens and other agencies, the more they are able to build trust. Specifically, enhanced communication, both between the various layers of government agencies, and between government and citizens tends to play a positive role in building of constructive interactions between central and local government and between local governments. Moreover, public officials’ interactions with citizens, as an antecedent of trust, can affect public officials’ general attitudes toward citizen participation in various areas of public administration based on mutual trust.

Mass Flow Analysis of Radionuclide Management Process Scenarios

Jungho Hur,Hun Suk Im,Hong Jang,Won Il Ko 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2

Nuclear power generation is expected to be enlarged for domestic electricity supply based on the 10th Basic Plan of Long-Term Electricity Supply and Demand. However, the issues on the disposal of spent nuclear fuel or high-level radioactive waste has not been solved. KBS-3 concept of the deep geological disposal and pyroprocessing has been investigated as options for disposal and treatment way of spent nuclear fuel. In other way, the radionuclide management process with 6 scenarios are devised combining chlorination treatment and alternative disposal methods for the efficient disposal of spent nuclear fuel. Various scenarios will be considered and comprehensively optimized by evaluation on many aspects, such as waste quantity, radiotoxicity, economy and so on. Level 0 to 4 were identified with the specialized nuclide groups: Level 0 (NFBC, Hull), Level 1 (Long-lived, volatile nuclides), Level 2 (High heat emitting nuclides), Level 3 (TRU/RE), Level 4 (U). The 6 options (Op.1 to 6) were proposed with the differences between scenarios, for examples, phase types of wastes, the isolated nuclide groups, chlorination process sequences. Op.1 adopts Level 0 and 1 to separate I, Tc, Se, C, Cs nuclides which are major concerns for long-term disposal through heat treatment. The rest of spent nuclear fuel will be disposed as oxide form itself. Op.2 contains Sr separation process using chlorination by MgCl2 and precipitation by K2CO3to alleviate the burden of heat after heat treatment process. U/TRU/RE will be remained and disposed in oxide form. Op.3 is set to pyroprocessing as reference method, but residual TRU/RE chlroides after electrorefining will be recovered as precipitates by K3PO4. Op.4 introduces NH4Cl to chlorinate TRU/RE from oxides after Op.2 applied and precipitates them. TRU/RE/Sr will be simultaneously chlorinated by NH4Cl without MgCl2 in Op.5. Then, chlorinated Sr and TRU/RE groups will be separated by post-chlorination process for disposal. But, chlorinated Sr and TRU/RE are designed not to be divided in disposal steps in Op.6. In this study, the mass flow analysis of radionuclide management process scenarios with updated process variables are performed. The amount and composition of wastes by types will be addressed in detail.

Hybrid crystalline-ITO/metal nanowire mesh transparent electrodes and their application for highly flexible perovskite solar cells

Im, Hyeon-Gyun,Jeong, Seonju,Jin, Jungho,Lee, Jaemin,Youn, Doo-Young,Koo, Won-Tae,Kang, Sin-Bi,Kim, Hyo-Joong,Jang, Junho,Lee, Daewon,Kim, Han-Ki,Kim, Il-Doo,Lee, Jung-Yong,Bae, Byeong-Soo Nature Publishing Group 2016 NPG Asia Materials Vol.8 No.-

<P>Here, we propose crystalline indium tin oxide/metal nanowire composite electrode (c-ITO/metal NW-GFRHybrimer) films as a robust platform for flexible optoelectronic devices. A very thin c-ITO overcoating layer was introduced to the surface-embedded metal nanowire (NW) network. The c-ITO/metal NW-GFRHybrimer films exhibited outstanding mechanical flexibility, excellent optoelectrical properties and thermal/chemical robustness. Highly flexible and efficient metal halide perovskite solar cells were fabricated on the films. The devices on the c-ITO/AgNW- and c-ITO/CuNW-GFRHybrimer films exhibited power conversion efficiency values of 14.15% and 12.95%, respectively. A synergetic combination of the thin c-ITO layer and the metal NW mesh transparent conducting electrode will be beneficial for use in flexible optoelectronic applications.</P>

다단연소사이클 엔진의 추진제 공급시스템 특성 및 운용

이정호(Jungho Lee),서대반(Daeban Seo),임지혁(Jihyuk Im),황창환(Changhwan Hwang),김채형(Chaehyoung Kim),우성필(Seongphil Woo),이광진(Kwangjin Lee),유병일(Byungil Yoo),조남경(Namkyung Cho),한영민(Yeoungmin Han) 한국추진공학회 2018 한국추진공학회 학술대회논문집 Vol.2018 No.12

Certificateless based Public Key Infrastructure using a DNSSEC

Hyungjin Im,Jungho Kang,Jong Hyuk Park 한국정보기술융합학회 2015 JoC Vol.6 No.3

With the continuous development of the internet, there has been increasing research on reliability of data shared through the network. In particular, the focus on the public key infrastructure (PKI) that performs functions including verifying the sender’s identity and preventing forgery based on digital certificates has been intensifying rapidly. However, existing certificate-based PKI gives rise to various problems in terms of the Certificate Authority (CA), user, and domain name system (DNS). Moreover, certificate-PKI involves cost, an authentication environment, and security, and the existing PKI system uses CA, a hierarchical structure, to process certificates. This paper aims to devise a reliable address using the DNS security extension (DNSSEC) that applies security to the existing DNS, and proposes a certificate less-based PKI that uses DNSSEC. The proposed PKI can reduce the cost of the existing certificate and address existing vulnerabilities.

세계 정부의 2014년 우주개발 투자 현황

임종빈(Im, Jongbin),이준(Lee, Joon),임창호(Lim changho),정서영(Chung, Soyoung),박정호(Park, Jungho),김은정(Kim, Eunjeong),최남미(Choi, Nammi) 한국항공우주연구원 2015 항공우주산업기술동향 Vol.13 No.2

세계적으로 우주개발에 대한 필요성이 증가하고 있으며, 이에 따른 많은 국가들이 새롭게 우주개발에 참여하고 있다. 천만 달러 이상을 우주개발에 투자하고 있는 나라는 2014년 60개국으로 이는 2004년에 비해 두 배 증가한 수치이다. 하지만 2013년도 세계 정부의 우주개발 예산이 약 20년 만에 처음으로 줄어들었는데, 이러한 현상이 2014년도에 이어졌다. 이는 미국의 예산 감소와 환율의 영향이 큰 것으로 보인다. 그럼에도 불구하고 향후 10년간 세계 정부의 우주개발 예산은 다시 증가할 것으로 예측되고 있다. 본 연구에서는 이러한 세계정부의 우주개발 투자 현황을 자세히 살펴보고자 한다. The number of countries involving in space development increases. In 2014, 60 countries invested more than 10 million dollars in space applications and technologies, twice as countries as in 2004. In 2013, for the first time in almost 20 years, government worldwide reduce spending on their space programs. This downward trend was confirmed in 2014. The main factors to reduce expenditures for space programs are U.S. military space expenditures dropping, exchange-rate fluctuation and pressures on government spending. However, a new growth cycle is expected to start with anticipated growth of government space spending over the next ten years worldwide. In this report, detailed information for government worldwide expenditures in 2014 are presented.