Feasibility study for image reconstruction in circular digital tomosynthesis (CDTS) from limited-scan angle data based on compressed-sensing theory

Park, Yeonok,Je, Uikyu,Cho, Hyosung,Hong, Daeki,Park, Chulkyu,Cho, Heemoon,Choi, Sungil,Woo, Taeho Elsevier 2015 Nuclear instruments & methods in physics research. Vol.777 No.-

<P><B>Abstract</B></P> <P>In this work, we performed a feasibility study for image reconstruction in a circular digital tomosynthesis (CDTS) from limited-scan angle data based on compressed-sensing (CS) theory. Here, the X-ray source moves along an arc within a limited-scan angle (≤ 180°) on a circular path set perpendicularly to the axial direction during the image acquisition. This geometry, compared to full-angle (360°) scan geometry, allows imaging system to be designed more compactly and gives better tomographic quality than conventional linear digital tomosynthesis (DTS). We implemented an efficient CS-based reconstruction algorithm for the proposed geometry and performed systematic simulations to investigate the image characteristics. We successfully reconstructed CDTS images with incomplete projections acquired at several selected limited-scan angles of 45°, 90°, 135°, and 180° for a given tomographic angle of 80° and evaluated the reconstruction quality. Our simulation results indicate that the proposed method can provide superior tomographic quality for axial view and even for the other views (<I>i.e.</I>, sagittal and coronal), as in computed tomography, to conventional DTS.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Image reconstruction is done in circular digital tomosynthesis (CDTS). </LI> <LI> The designed geometry allows imaging system to be the better image. </LI> <LI> An efficient compressed-sensing (CS)-based reconstruction algorithm is performed. </LI> <LI> Proposed method can provide superior tomographic quality for the axial view. </LI> </UL> </P>

일반국도 자산관리시스템 도입을 위한 기본체계 구축에 관한 연구

Hyosung Park,Soohyng Lee 한국재난정보학회 2014 한국재난정보학회 논문집 Vol.10 No.2

우리나라의 경우 그동안 도로부문의 투자는 신규건설 그 자체가 정부 정책의 핵심이었다. 그러나 최근 정부의 도로부문 예산이 2000년을 정점으로 신규건설은 감소하고 유지관리는 증가하는 추세이다. 이러한 추세에서 도로 유지관리 예산 증가에 대한 정당성을 입증하면 서 서비스수준에 대한 사용자 요구에 부응할 수 있는 새로운 도로정책 패러다임이 필요하 다. 1950~60년대에 사회기반시설을 집중적으로 건설하였던 선진국들이 최근 공공시설물의 노후화에 대처하기 위해 자산관리 개념을 도입하여 많은 성과를 거두고 있다. 본 연구에서 는 일반국도의 효율적인 유지관리를 위해 "한국형 도로 자산관리시스템"을 구축하는데 필 요한 기본체계를 제시하였다. 이 시스템의 특징은 장기적이며 예방적인 도로 유지관리 정 책을 수립할 수 있도록 기존의 포장관리시스템에 경제성 분석 과정을 포함시키는데 있다.

Precise nanoinjection delivery of plasmid DNA into a single fibroblast for direct conversion of astrocyte

Park, Hang-Soo,Kwon, Hyosung,Yu, Jewon,Bae, Yeonju,Park, Jae-Yong,Choi, Kyung-Ah,Choi, Yeonho,Hong, Sunghoi Informa UK (TaylorFrancis) 2018 Artificial cells, nanomedicine, and biotechnology Vol.46 No.suppl1

일반국도 자산관리시스템 도입을 위한 기본체계 구축에 관한 연구

Park, Hyosung,Lee, Soohyng 한국재난정보학회 2014 한국재난정보학회 논문집 Vol.10 No.2

우리나라의 경우 그동안 도로부문의 투자는 신규건설 그 자체가 정부 정책의 핵심이었다. 그러나 최근 정부의 도로부문 예산이 2000년을 정점으로 신규건설은 감소하고 유지관리는 증가하는 추세이다. 이러한 추세에서 도로 유지관리 예산 증가에 대한 정당성을 입증하면서 서비스수준에 대한 사용자 요구에 부응할 수 있는 새로운 도로정책 패러다임이 필요하다. 1950~60년대에 사회기반시설을 집중적으로 건설하였던 선진국들이 최근 공공시설물의 노후화에 대처하기 위해 자산관리 개념을 도입하여 많은 성과를 거두고 있다. 본 연구에서는 일반국도의 효율적인 유지관리를 위해 "한국형 도로 자산관리시스템"을 구축하는데 필요한 기본체계를 제시하였다. 이 시스템의 특징은 장기적이며 예방적인 도로 유지관리 정책을 수립할 수 있도록 기존의 포장관리시스템에 경제성 분석 과정을 포함시키는데 있다. The government policy had placed new construction as the kernel of the investment in the road department. This had been shifted, however, since the government's budget of the road department reached its peak in 2000, new construction had came to a downsizing phase while the maintenance increased gradually. Considering this recent trend, the necessity of a new paradigm in the road policy had came to a fore, in order to prove the justification of increase in the maintenance budget as well as successfully fulfill the user's needs in the service quality. The developed countries that had intensively constructed social infrastructure in 1950-60s are enjoying a great achievement by applying the asset management concept in coping with the deterioration of the public facilities. This research suggests the basic framework in establishing "Korean Road Asset Management System" designed to efficiently manage the national road. The main feature of this system is to absorb economic analysis course into the current pavement management system, in order to form not only long-lasting but also preventive road management policy.

Multipositional Silica-Coated Silver Nanoparticles for High-Performance Polymer Solar Cells

Choi, Hyosung,Lee, Jung-Pil,Ko, Seo-Jin,Jung, Jae-Woo,Park, Hyungmin,Yoo, Seungmin,Park, Okji,Jeong, Jong-Ryul,Park, Soojin,Kim, Jin Young American Chemical Society 2013 Nano letters Vol.13 No.5

<P>We demonstrate high-performance polymer solar cells using the plasmonic effect of multipositional silica-coated silver nanoparticles. The location of the nanoparticles is critical for increasing light absorption and scattering via enhanced electric field distribution. The device incorporating nanoparticles between the hole transport layer and the active layer achieves a power conversion efficiency of 8.92% with an external quantum efficiency of 81.5%. These device efficiencies are the highest values reported to date for plasmonic polymer solar cells using metal nanoparticles.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2013/nalefd.2013.13.issue-5/nl400730z/production/images/medium/nl-2013-00730z_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl400730z'>ACS Electronic Supporting Info</A></P>

COVID-19 상황 원격강의에서 대학생이 인식하는 학습실재감과 학습성과 관계 탐색

박효성 ( Hyosung Park ),소효정 ( Hyo-jeong So ) 한국교육정보미디어학회(구 한국교육정보방송학회) 2021 교육정보미디어연구 Vol.27 No.1

본 연구는 일반대학에서 코로나19의 대응차원으로 이루어진 원격강의에 대해 대학생이 인식하는 학습실재감(인지적, 감성적, 사회적)과 학습성과의 관계를 탐색하였다. 본 연구에서 검증한 구체적 연구 문제는 다음과 같다: (1) 학생들이 원격강의에서 인식한 학습실재감(인지적, 감성적, 사회적)은 학습만족도를 유의하게 예측하는가?, (2) 학생들이 원격강의에서 인식한 학습실재감(인지적, 감성적, 사회적)은 학습지속의향을 유의하게 예측하는가?, (3) 원격강의 유형(실시간, 비실시간, 혼합)에 따라 학생들이 인식하는 학습실재감(인지적, 감성적, 사회적)에 차이가 있는가? 본 연구문제의 검증을 위해 2020학년도 1학기에 원격강의를 경험한 일반대학 학부생 215명을 대상으로 설문조사를 실시하였다. 분석 결과, 학습실재감의 요인 중 인지적 실재감과 감성적 실재감은 학습만족도와 학습지속의향을 유의하게 예측하나, 사회적 실재감은 학습만족도와 학습지속의향을 예측하지 않는 것으로 나타났다. 또한 인지적 실재감은 원격강의 유형에 따라 유의한 차이가 있으며, 특히 혼합과 비실시간 유형의 차이가 통계적으로 유의한 것으로 나타났다. 본 연구는 코로나19라는 외부적 요인의 대응적 차원으로 일반대학에서 긴박하게 이루어진 원격강의 환경이라는 특수성에 주목하여 학습자의 학습실재감과 학습성과간의 관계를 규명하고 원격강의 유형별로 학습실재감의 차이를 검증했다는 점에서 의의를 가진다. This study explored the relationship between learning presence (cognitive, emotional, social) and learning performance perceived by university students for distance lectures in response to the Corona 19 pandemic in general universities. Specific research questions verified in this study are as follows: (1) Does the sense of learning presence (cognitive, emotional, social) perceived by students in distance lectures significantly predict learning satisfaction?; (2) Does the sense of learning presence (cognitive, emotional, social) perceived by students in distance lectures significantly predict their willingness to continue learning?; (3) Is there a difference in the sense of learning presence (cognitive, emotional, social) perceived by students according to the type of distance lectures (synchronous, asynchronous, mixed)? To verify the research questions, a questionnaire survey was conducted on 215 undergraduate students in general universities who experienced distance lectures in the first semester of 2020. The results indicate that cognitive presence and emotional presence among the factors of learning presence significantly predicted learning satisfaction and willingness to continue learning, but social presence did not predict learning satisfaction and willingness to continue learning. In addition, there was a significant difference in cognitive presence according to the type of distance lectures, and in particular, the difference between the mixed and asynchronous types was statistically significant. This study examines the relationship between the learner's learning presence and learning performance by paying attention to the peculiarity of the remote learning environment, which is urgently designed in general universities as a response to the external factor of Corona 19, and verifies the difference in learning presence by distance lecture types.

Feasibility Study for Improving the Image Characteristics in Digital Tomosynthesis (DTS) Using a Compressed-Sensing (Cs)-Based Pre-Deblurring Scheme

Kim, Kyuseok,Park, Soyoung,Kim, Guna,Cho, Hyosung,Je, Uikyu,Park, Chulkyu,Lim, Hyunwoo,Lee, Dongyeon,Lee, Hunwoo,Park, Yeonok,Woo, Taeho SPRINGER VERLAG KG 2018 RESEARCH IN NONDESTRUCTIVE EVALUATION Vol.29 No.2

<P>Digital tomosynthesis (DTS) has been widely used in both industrial nondestructive testing and medical x-ray imaging as a popular multiplanar imaging modality. However, although it provides some of the tomographic benefits of computed tomography (CT) at reduced dose and imaging time, the image characteristics are relatively poor due to blur artifacts originated from incomplete data sampling for a limited angular range and also aspects inherent to imaging system, including finite focal spot size of the x-ray source, detector resolution, etc. In this work, in order to overcome these difficulties, we propose an intuitive method in which a compressed-sensing (CS)-based deblurring scheme is applied to the projection images before common DTS reconstruction. We implemented the proposed deblurring algorithm and performed a systematic experiment to demonstrate its viability for improving the image characteristics in DTS. According to our results, the proposed method appears to be effective for the blurring problems in DTS and seems to be promising to our ongoing application to x-ray nondestructive testing.</P>

Industrial x-ray inspection system with improved image characterization using blind deblurring based on compressed-sensing scheme

Kim, Kyuseok,Park, Soyoung,Kim, Guna,Cho, Hyosung,Je, Uikyu,Park, Chulkyu,Lim, Hyunwoo,Lee, Hunwoo,Lee, Dongyeon,Park, Yeonok,Woo, Taeho Taylor Francis 2017 Instrumentation science & technology Vol.45 No.3

RTV 도포부 가스패스 제거공정 연구

박용수(Yongsoo Park),이상진(Sangjin Lee),김성수(Sungsoo Kim),탁효성(Hyosung Tak),백기봉(Kibong Baek),박민수(Minsoo Park),노영희(Younghee Roh) 한국추진공학회 2022 한국추진공학회 학술대회논문집 Vol.2022 No.11

A New Voxelization Strategy in Compressed-Sensing (CS)-Based Iterative CT Reconstruction for Reducing Computational Cost: Simulation and Experimental Studies

Kim, Guna,Park, Soyoung,Je, Uikyu,Cho, Hyosung,Park, Chulkyu,Kim, Kyuseok,Lim, Hyunwoo,Lee, Dongyeon,Lee, Hunwoo,Park, Yeonok,Woo, Taeho Springer-Verlag 2018 Journal of medical and biological engineering Vol.38 No.1

<P>In recent computed tomography (CT) reconstruction, iterative methods have been often used owing to the potential to provide three-dimensional (3D) images of superior reconstruction quality to common filtered-back-projection (FBP)-based methods. However, these methods require enormous computational cost in the iterative process, which has still been an obstacle to put them to practical use. In this work, to overcome these difficulties, we propose a new cone-beam CT reconstruction with a dual-resolution voxelization strategy for a small region-of-interest (ROI) reconstruction in which the voxels outside the target ROI are binned by, for example, 2 x 2 x 2, 4 x 4 x 4, 8 x 8 x 8, etc., while the other voxels remain unbinned. We considered a compressed-sensing (CS)based algorithm with a dual regularization strategy, rather than common FBP-based methods, for more accurate CT reconstruction. We implemented the proposed CS-based algorithm and performed a systematic simulation and experiment. Our results indicate that the proposed method seems to be effective for reducing computational cost considerably in iterative CT reconstruction, keeping the reconstruction quality inside the target ROI not much degraded.</P>