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1. The Use of Multi-Scale Fiducial Markers To Aid Takeoff and Landing Navigation by Rotorcraft

Author

Lee, Jongwon, Choi, Su Yeon, and Bretl, Timothy

Subjects
Computer Science - Computer Vision and Pattern Recognition, Computer Science - Robotics
Abstract

This paper quantifies the performance of visual SLAM that leverages multi-scale fiducial markers (i.e., artificial landmarks that can be detected at a wide range of distances) to show its potential for reliable takeoff and landing navigation in rotorcraft. Prior work has shown that square markers with a black-and-white pattern of grid cells can be used to improve the performance of visual SLAM with color cameras. We extend this prior work to allow nested marker layouts. We evaluate performance during semi-autonomous takeoff and landing operations in a variety of environmental conditions by a DJI Matrice 300 RTK rotorcraft with two FLIR Blackfly color cameras, using RTK GNSS to obtain ground truth pose estimates. Performance measures include absolute trajectory error and the fraction of the number of estimated poses to the total frame. We release all of our results -- our dataset and the code of the implementation of the visual SLAM with fiducial markers -- to the public as open-source., Comment: Accepted at the 2024 AIAA SciTech

Published
2023

2. Comparative Study of Visual SLAM-Based Mobile Robot Localization Using Fiducial Markers

Author

Lee, Jongwon, Choi, Su Yeon, Hanley, David, and Bretl, Timothy

Subjects
Computer Science - Robotics, Computer Science - Computer Vision and Pattern Recognition
Abstract

This paper presents a comparative study of three modes for mobile robot localization based on visual SLAM using fiducial markers (i.e., square-shaped artificial landmarks with a black-and-white grid pattern): SLAM, SLAM with a prior map, and localization with a prior map. The reason for comparing the SLAM-based approaches leveraging fiducial markers is because previous work has shown their superior performance over feature-only methods, with less computational burden compared to methods that use both feature and marker detection without compromising the localization performance. The evaluation is conducted using indoor image sequences captured with a hand-held camera containing multiple fiducial markers in the environment. The performance metrics include absolute trajectory error and runtime for the optimization process per frame. In particular, for the last two modes (SLAM and localization with a prior map), we evaluate their performances by perturbing the quality of prior map to study the extent to which each mode is tolerant to such perturbations. Hardware experiments show consistent trajectory error levels across the three modes, with the localization mode exhibiting the shortest runtime among them. Yet, with map perturbations, SLAM with a prior map maintains performance, while localization mode degrades in both aspects., Comment: IEEE 2023 IROS Workshop "Closing the Loop on Localization". For more information, see https://oravus.github.io/vpr-workshop/index

Published
2023

7. The Impacts of a Climate Change SSI-STEAM Program on Junior High School Students' Climate Literacy

Author

Choi, Su-Yeon, Won, A-Rang, Chu, Hye-Eun, Cha, Hyun-Jung, Shin, Hyeonjeong, and Kim, Chan-Jong

Abstract

This study aims to investigate climate literacy among junior high school students participating in an SSI-STEAM climate change education program and to examine the impacts of the program on the cultivation of climate literacy. Thirty-one eighth-grade students in Seoul, Korea, participated in this study. Data were collected using pre- and post-program surveys with a climate literacy questionnaire (CLQ), students' background survey questions, interviews with participants, and from the artifacts produced by students during the program. Participants' climate literacy was shown to improve substantially after attending the program, especially in the domains of perception and action. The four characteristics of climate literacy change were identified in the participants' responses: more concrete ideas, extension of the scope of thinking, positive responsibility, and relevance recognition. The climate literacy program developed showed potential for fostering young people's climate literacy along with their understanding of responsible national and global citizenship. The study discusses the implications of these findings and includes suggestions for future climate literacy program development and for both curricular and extra-curricular climate change education that can together nurture students' more profound understanding of climate change.

Published
2021
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8. A Teacher's Practical Knowledge in an SSI-STEAM Program Dealing with Climate Change

Author

Won, A-Rang, Choi, Su-Yeon, Chu, Hye-Eun, Cha, Hyun-Jung, Shin, Hyeonjeong, and Kim, Chan-Jong

Abstract

Teachers do not simply deliver a set curriculum, but carry out classes based on practical knowledge, including their values, beliefs, and experiences. Therefore, it is meaningful to investigate the practical knowledge of teaching among teachers in terms of orientation, structure, and content in order to understand the teacher's knowledge, conflicts, and trial and error experiences in the classroom. In this study, we explored the practical knowledge of a teacher conducting SSI-STEAM classes themed on climate change. In the specific context of SSI-STEAM classes, it was possible to understand how the teacher organized climate change classes and guided the actions of students in action-oriented classes. In addition, we expect that this study, which examines the practical knowledge of a novice teacher, will serve as the first step in narrowing the gap in SSI-STEAM education between pre-service teacher education and actual school classroom experience.

Published
2021
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28. Various Obesity Indices and Arterial Function Evaluated with CAVI – Is Waist Circumference Adequate to Define Metabolic Syndrome?

Author

Nagayama,Daiji, Sugiura,Tomonori, Choi,Su-Yeon, and Shirai,Kohji

Subjects
Vascular Health and Risk Management
Abstract

Daiji Nagayama,1,2 Tomonori Sugiura,3 Su-Yeon Choi,4 Kohji Shirai5 1Department of Internal Medicine, Nagayama Clinic, Tochigi, Japan; 2Center of Diabetes, Endocrinology and Metabolism, Toho University, Sakura Medical Center, Chiba, Japan; 3Department of Cardiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan; 4Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Hospital Healthcare System Gangnam Center, Seoul, Republic of Korea; 5Department of Internal Medicine, Mihama Hospital, Chiba, JapanCorrespondence: Daiji Nagayama, Nagayama Clinic, 2-12-22, Tenjin-Cho, Oyama-City, Tochigi, 323-0032, Japan, Tel/Fax +81-285-22-0219, Email deverlast96071@gmail.comAbstract: Obesity has been known to relate to various diseases and metabolic disorders. Since the implication of body shape has been mentioned, obesity can be divided into visceral obesity and subcutaneous obesity. The former is considered the upstream pathophysiology of metabolic syndrome (MetS), and has been emphasized worldwide for the prevention of cardiovascular diseases in the last quarter century. However, some prospective studies have shown that cardiovascular mortality and morbidity are not necessarily higher in patients with MetS compared to those without. Recently, cardio-ankle vascular index (CAVI) has been established as an indicator of arteriosclerosis. This parameter is independent of blood pressure at the measuring time, and reflects systemic arterial stiffness from the aortic origin to the ankle. However, since CAVI is not necessarily high in MetS patients, attempts have been made to clarify this unexpected phenomenon. In several studies, CAVI was found to correlate negatively with body mass index (BMI), and also with waist circumference (WC) which is a widely used representative visceral obesity index. On the other hand, a body shape index (ABSI) is also a visceral obesity index designed to be minimally associated with BMI, and is calculated by dividing WC by an allometric regression of weight and height. Replacing high WC with high ABSI in MetS diagnosis promoted the identification of MetS patients with increased CAVI in cross-sectional studies on Japanese and Korean populations. Additionally, the incidence of MetS diagnosed using high ABSI was associated with significant increase in CAVI after 1 year of observation. Enhanced predictive ability for renal function decline by replacing WC with ABSI in MetS diagnosis was also observed in a longitudinal study in Japanese urban residents. These findings suggest that MetS diagnosis using high ABSI instead of high WC as a visceral obesity index needs to be reconsidered. However, further research is desirable on Caucasian, whose body shape differs slightly from that of Asians.Keywords: CAVI, metabolic syndrome, waist circumference, a body shape index, renal function decline

Published
2022

30. Impact of a Telehealth Program With Voice Recognition Technology in Patients With Chronic Heart Failure: Feasibility Study

Author

Lee, Heesun, Park, Jun-Bean, Choi, Sae Won, Yoon, Yeonyee E, Park, Hyo Eun, Lee, Sang Eun, Lee, Seung-Pyo, Kim, Hyung-Kwan, Cho, Hyun-Jai, Choi, Su-Yeon, Lee, Hae-Young, Choi, Jonghyuk, Lee, Young-Joon, Kim, Yong-Jin, Cho, Goo-Yeong, Choi, Jinwook, and Sohn, Dae-Won

Subjects
Information technology, T58.5-58.64, Public aspects of medicine, RA1-1270
Abstract

BackgroundDespite the advances in the diagnosis and treatment of heart failure (HF), the current hospital-oriented framework for HF management does not appear to be sufficient to maintain the stability of HF patients in the long term. The importance of self-care management is increasingly being emphasized as a promising long-term treatment strategy for patients with chronic HF. ObjectiveThe objective of this study was to evaluate whether a new information communication technology (ICT)–based telehealth program with voice recognition technology could improve clinical or laboratory outcomes in HF patients. MethodsIn this prospective single-arm pilot study, we recruited 31 consecutive patients with chronic HF who were referred to our institute. An ICT-based telehealth program with voice recognition technology was developed and used by patients with HF for 12 weeks. Patients were educated on the use of this program via mobile phone, landline, or the Internet for the purpose of improving communication and data collection. Using these systems, we collected comprehensive data elements related to the risk of HF self-care management such as weight, diet, exercise, medication adherence, overall symptom change, and home blood pressure. The study endpoints were the changes observed in urine sodium concentration (uNa), Minnesota Living with Heart Failure (MLHFQ) scores, 6-min walk test, and N-terminal prohormone of brain natriuretic peptide (NT-proBNP) as surrogate markers for appropriate HF management. ResultsAmong the 31 enrolled patients, 27 (87%) patients completed the study, and 10 (10/27, 37%) showed good adherence to ICT-based telehealth program with voice recognition technology, which was defined as the use of the program for 100 times or more during the study period. Nearly three-fourths of the patients had been hospitalized at least once because of HF before the enrollment (20/27, 74%); 14 patients had 1, 2 patients had 2, and 4 patients had 3 or more previous HF hospitalizations. In the total study population, there was no significant interval change in laboratory and functional outcome variables after 12 weeks of ICT-based telehealth program. In patients with good adherence to ICT-based telehealth program, there was a significant improvement in the mean uNa (103.1 to 78.1; P=.01) but not in those without (85.4 to 96.9; P=.49). Similarly, a marginal improvement in MLHFQ scores was only observed in patients with good adherence (27.5 to 21.4; P=.08) but not in their counterparts (19.0 to 19.7; P=.73). The mean 6-min walk distance and NT-proBNP were not significantly increased in patients regardless of their adherence. ConclusionsShort-term application of ICT-based telehealth program with voice recognition technology showed the potential to improve uNa values and MLHFQ scores in HF patients, suggesting that better control of sodium intake and greater quality of life can be achieved by this program.

Published
2017
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38. Association Among Local Hemodynamic Parameters Derived From CT Angiography and Their Comparable Implications in Development of Acute Coronary Syndrome

Author

Yang, Seokhun, primary, Choi, Gilwoo, additional, Zhang, Jinlong, additional, Lee, Joo Myung, additional, Hwang, Doyeon, additional, Doh, Joon-Hyung, additional, Nam, Chang-Wook, additional, Shin, Eun-Seok, additional, Cho, Young-Seok, additional, Choi, Su-Yeon, additional, Chun, Eun Ju, additional, Nørgaard, Bjarne L., additional, Nieman, Koen, additional, Otake, Hiromasa, additional, Penicka, Martin, additional, Bruyne, Bernard De, additional, Kubo, Takashi, additional, Akasaka, Takashi, additional, Taylor, Charles A., additional, and Koo, Bon-Kwon, additional

Published
2021
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41. Effect of Moderately but Persistently Elevated Lipid Levels on Risks of Stroke and Myocardial Infarction in Young Korean Adults

Author

Park, Jun‐Bean, primary, Kim, Da Hye, additional, Lee, Heesun, additional, Lee, Hyun‐Jung, additional, Hwang, In‐Chang, additional, Yoon, Yeonyee E., additional, Park, Hyo Eun, additional, Lee, Seung‐Pyo, additional, Choi, Su‐Yeon, additional, Kim, Yong‐Jin, additional, Cho, Goo‐Yeong, additional, Han, Kyungdo, additional, and Kim, Hyung‐Kwan, additional

Published
2021
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44. Additional file of Concurrent smoking and alcohol consumers had higher triglyceride glucose indices than either only smokers or alcohol consumers: a cross-sectional study in Korea

Author

Wonhee Baek, Lee, Ji-Won, Lee, Hye Sun, Donghee Han, Choi, Su-Yeon, Chun, Eun Ju, Hae-Won Han, Park, Sung Hak, Jidong Sung, Jung, Hae Ok, Lee, Hyangkyu, and Hyuk-Jae Chang

Abstract

Additional file of Concurrent smoking and alcohol consumers had higher triglyceride glucose indices than either only smokers or alcohol consumers: a cross-sectional study in Korea

Published
2021
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45. Sex differences in coronary artery calcium progression: The Korea Initiatives on Coronary Artery Calcification (KOICA) registry

Author

Lee, Wonjae, primary, Yoon, Yeonyee E., additional, Cho, Sang-Young, additional, Hwang, In-Chang, additional, Kim, Sun-Hwa, additional, Lee, Heesun, additional, Park, Hyo Eun, additional, Chun, Eun Ju, additional, Kim, Hyung-Kwan, additional, Choi, Su-Yeon, additional, Park, Sung Hak, additional, Han, Hae-Won, additional, Sung, Jidong, additional, Jung, Hae Ok, additional, Cho, Goo-Yeong, additional, and Chang, Hyuk-Jae, additional

Published
2021
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47. Additional file 2 of Triglyceride glucose index is an independent predictor for the progression of coronary artery calcification in the absence of heavy coronary artery calcification at baseline

Author

Ki-Bum Won, Park, Eun Ji, Donghee Han, Lee, Ji Hyun, Choi, Su-Yeon, Chun, Eun Ju, Park, Sung Hak, Hae-Won Han, Jidong Sung, Jung, Hae Ok, and Chang, Hyuk-Jae

Abstract

Additional file 2: Table S2. TyG index (per 1-unit increase) and the risk of CAC progression according to baseline CACS 100.

Published
2020
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48. Additional file 1 of Triglyceride glucose index is an independent predictor for the progression of coronary artery calcification in the absence of heavy coronary artery calcification at baseline

Author

Ki-Bum Won, Park, Eun Ji, Donghee Han, Lee, Ji Hyun, Choi, Su-Yeon, Chun, Eun Ju, Park, Sung Hak, Hae-Won Han, Jidong Sung, Jung, Hae Ok, and Chang, Hyuk-Jae

Subjects
endocrine system diseases, cardiovascular system, population characteristics, nutritional and metabolic diseases, cardiovascular diseases
Abstract

Additional file 1: Table S1. Association between clinical variables and CAC progression.

Published
2020
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