Stray electric field energy harvesting technology using MEMS switch from insulated AC power lines

Park, Kyungjin,Choi, Dongkil,Kim, Hoseong,Gong, Sungmin Institution of Electrical Engineers 2014 Electronics letters Vol.50 No.17

Visualization Study on Microscale Wetting Dynamics of Water Droplets on Dry and Wet Hydrophilic Membranes

( Kyungjin Park ),( Seong Yeon Kim ),( Jiwoo Hong ),( Jong Hyun Kim ),( Geunbae Lim ) 한국화학공학회 2022 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.60 No.2

The wetting dynamics of water droplets dispensed on the surface of dry and wet hydrophilic membranes were investigated experimentally from a microscale point of view. By using a high-speed, white-beam x-ray microimaging (WXMI) synchrotron, consecutive images displaying the dynamic motions of the droplets were acquired. Through analyzing the characteristics observed, it was found that the dry hydrophilic membrane showed local hydrophobicity at a certain point during the absorption process with apparent contact angles greater than 90. While on the other hand, the apparent contact angles of a water droplet absorbing into the wet membrane remained less than 90 and showed total hydrophilicity. The observations and interpretation of characteristics that affect the contact, wetting, recoiling, and dynamic behaviors of droplets are significant for controlling liquid droplet impingement in a desired manner.

High-Speed X-Ray Projection Microscopy at Beamline 9D of the Pohang Light Source-II

Park Kyungjin,Kim Seob-Gu,Lee Ye Ji,Lim Jae-Hong,Kim Jong Hyun 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.9

We constructed a high-speed X-ray projection microscope at beamline 9D of the Pohang Light Source-II (PLS-II). The microscope was able to take X-ray projection micrographs with a submillisecond exposure time by using whitebeam X-rays from the PLS-II bending-magnet synchrotron radiation. It also takes advantage of edge enhancement in phase-contrast imaging, which significantly improves the visibility of soft materials and microfluids. Using the microscope, we captured the spreading of a water droplet on a hydrophilic and oleophilic nonwoven membrane at 1,264 frames per second. The computed tomography (CT), which visualized a three-dimensional wooden structure at a spatial resolution of 2.7 μm, took 2.5 s for scanning.

On-road Vehicle Tracking using Laser Scanner with Multiple Hypothesis Assumption

Kyungjin Ryu,Seongkeun Park,Jae Pil Hwang,Euntai Kim,Mignon Park 한국지능시스템학회 2009 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.9 No.3

Active safety vehicle devices are getting more attention recently. To prevent traffic accidents, the environment in front and even around the vehicle must be checked and monitored. In the present applications, mainly camera and radar based systems are used as sensing devices. Laser scanner, one of the sensing devices, has the advantage of obtaining accurate measurement of the distance and the geometric information about the objects in the field of view of the laser scanner. However. there is a problem that detecting object occluded by a foreground one is difficult. In this paper, criterions are proposed to manage this problem. Simulation is conducted by vehicle mounted the laser scanner and multiple-hypothesis algorithm tracks the candidate objects. We compare the running times as multi-hypothesis algorithm parameter varies.

Paper-Based Printed Circuit Boards

Kyungjin Kim,Hyangwon Jang,Chan Won Park,Hun-Kuk Park,Samjin Choi 제어로봇시스템학회 2015 제어로봇시스템학회 국제학술대회 논문집 Vol.2015 No.10

아동문학 텍스트 활용 리터러시 활동이 초등학생의 비판적 사고 성향 및 영어 발화에 미치는 효과

박경진(Park, Kyungjin) 학습자중심교과교육학회 2021 학습자중심교과교육연구 Vol.21 No.15

목적 본 연구에서는 아동문학 텍스트를 활용한 리터러시 활동이 초등학생의 비판적 사고 성향과 영어 발화 능력에 미치는 효과를 탐구하였다. 방법 이를 위하여 서울시 소재 초등학교 5학년 31명을 대상으로 1학기와 2학기에 걸쳐 아동문학 텍스트를 활용한 리터러시 수업을 진행하고 수업 활동지, 저널, 비판적 사고 성향 검사지, 소감문, 면담 등을 비롯한 다양한 자료를 수집하여 양적 및 질적으로 분석하였다. 결과 첫째, 비판적 사고 성향 측면에서 참여 아동들의 개방성, 독립성, 객관성, 탐구성의 긍정적인 변화를 볼 수 있었다. 비판적 사고 성향 검사 결과, 개방성이 가장 높았고 독립성은 낮은 편이었으나 상승 폭이 가장 크게 나타났다. 객관성 또한 높은 편이었으며 탐구성은 가장 낮은 점수를 보였다. 둘째, 비판적 사고 성향의 변화는 아동들의 영어 발화를 촉진하였다. 개방성은 의견을 공유하는 음성 언어 발화와 다른 관점이나 문화를 고려하는 태도를 반영한 문자 언어 발화에 도움이 되었다. 독립성은 텍스트의 문제점을 인식하여 비판하는 문자 언어 발화를 촉진하였으며 객관성을 통해서는 근거를 요청하는 음성 언어 발화와 자기 생각에 대한 이유나 근거를 적어보는 문자 언어 발화가 이루어졌다. 탐구성은 스스로 탐구한 내용을 적어보는 문자 언어 발화를 촉진하였다. 결론 아동문학 활용 리터러시 활동을 통한 언어와 사고 교수의 통합적 접근은 학습자의 목표어 발화 능력과 비판적 사고 성향을 동시에 길러줄 수 있다. 이 연구를 기반으로 심화된 연구들이 다양한 맥락에서 시도되기를 기대한다. Objectives The purpose of this study was to investigate the effects of literacy activities using children’s literature on primary English and critical thinking dispositions. Methods The researcher selected 31 fifth grade students and taught English throughout a school year. Data from diverse sources were analyzed mainly in a qualitative manner. Results First, the literacy activities using children’s literature had a positive influence on children’s critical thinking dispositions. As a result of the critical thinking dispositions test, positive changes in open-mindedness, independence, objectivity, and inquisitiveness were found. Open-mindedness was the highest among the four sub-areas of critical thinking dispositions. Independence was relatively low, but the rise was the largest among the four. Objectivity was second highest and inquisitiveness was the lowest. Second, the changes of critical thinking dispositions promoted children’s English productive skills. Open-mindedness helped with spoken language production by sharing each other’s opinions. In addition, understanding various viewpoints and respecting other cultures promoted children’s written language production. Independence mainly promoted writing that questioning or criticizing the text. Through objectivity, it promoted spoken language production that requests a reason or rationale. It also helped children’s written language production to write down sufficient reason and rationale for one’s thoughts. Inquisitiveness mainly affected children’s writing where they would write down the results of their exploring with a desire for learning. Conclusions The integrated approach of language and thinking instruction using literacy activities has a positive effect on the learners’ English productive skills and critical thinking dispositions. Based on the results, implications were provided.

MEMS/MOSFET 하이브리드 스위치를 이용한 자가전원 무선센서

박경진(Kyungjin Park),강성묵(Sungmuk Kang),박재우(Jaewoo Park),백창욱(Changwook Baek),김호성(Hoseong Kim) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7

Energy Scavenging 기술을 이용한 자가전원 무선 센서용 전원분리 스위치로 초저누설, 초저전력 MEMS/MOSFET Hybrid 스위치를 제안한다. MEMS/MOSFET Hybrid 스위치는 컨트롤 신호 외에는 동작을 위한 전원이 필요 없으면서, 기계적으로 전원을 분리시켜 주는 MEMS 스위치의 장점과 다양한 크기의 전류를 제어할 수 있는 MOSFET 스위치의 장점을 모두 가지고 있다. 본 논문에서는 이러한 MEMS/MOSFET Hybrid 스위치를 사용하여 solar cell을 이용한 자가 전원 무선 온도 센서를 제작하고, 그 성능을 확인하기 위해 동일한 동작을 하는 MIT의 회로와 데이터 송신 비교 실험을 하였다. 그 결과, 일반 사무실 실내 조명(300 lux)에서 7.542초 마다 20m 거리까지 데이터를 보낼 수 있었고 이는 MIT 회로 보다 송신 주기가 37% 향상됨을 확인하였다.

흡착식 냉동기용 MOF 흡착제의 흡착 성능특성

배경진(Kyungjin Bae),진정(Ting Chen),박제성(Jeasung Park),박인(In Park),권오경(Ohkyung Kwon) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12

아동문학 활용 리터러시 활동이 초등영어 학습자의 비판적 사고 기능과 발화에 미치는 영향

박경진(Park, Kyungjin) 팬코리아영어교육학회(구 영남영어교육학회) 2021 영어교육연구 Vol.33 No.2

This study aims to explore the effects of literacy activities using children’s literature on critical thinking skills and language production in primary English lessons. The literacy activities were focused on critical literacy which reflects on text and the world to seek practical ways to create a better world. The researcher selected 31 fifth grade students and taught English throughout a school year. Data from diverse sources were analyzed mainly in a qualitative manner. The results of the study are as follows. First, the literacy instruction using children’s literature had a positive influence on students’ critical thinking skills. As a result of analyzing the students’ journals, they were able to develop critical thinking skills through inference, analysis, interpretation, and evaluation. Second, the improvement of critical thinking skills promoted students’ English productive skills. It was possible to promote students’ speaking and writing to draw a reasonable conclusion through the inference. Students could develop the analysis skill while analyzing characters and it mainly promoted their writing to reveal relationships. The interpretation skill promoted spoken language production about the hidden meaning of the object. Through the evaluation skill, it was possible to improve students’ English production reflecting the improved thinking. Based on the results, implications were provided. (199 words)

Distribution of medical status and medications in elderly patients treated with dental implant surgery covered by national healthcare insurance in Korea

Lee, Kyungjin,Dam, Chugeum,Huh, Jisun,Park, Kyeong-Mee,Kim, Seo-Yul,Park, Wonse The Korean Dental Society of Anesthsiology 2017 Journal of Dental Anesthesia and Pain Medicine Vol.17 No.2

Background: The purpose of this study was to investigate the distribution of systemic diseases and medications in patients older than 65 years of age who visited the hospital for implant treatment, as well as to investigate basic information about surgical complications that may occur after insured implant treatment. Method: A total of 126 patients over 65 years of age were treated for implant surgery from October 1, 2013 to October 30, 2016. Electronic chart review was conducted to obtain medical records, which included sex, age, systemic diseases, medication(s) being taken, and control of the medications. Five patients were excluded due to lack of medical records giving information about systemic disease. Results: Of the 126 patients, 112 (88.9%) were taking medication due to systemic disease and 9 patients (7.1%) were not. The sex distribution was 71 women and 55 men and the highest proportion of patients were between 65 and 69 years old. The most common diseases were, from most to least frequent, hypertension, cardiovascular disease, diabetes, and osteoporosis. The drug groups that can cause major complications after dental treatment were classified as hemorrhagic, osteoporotic, and immunosuppressive agents, and were taken by 45 (35.7%), 22 (17.5%) and 4 (3.2%) patients, respectively. Conclusion: Given that 88.9% of the elderly patients who were eligible for insurance implant treatment had systemic disease, it is necessary to carefully evaluate patients' medical histories and their general conditions in order to prevent emergencies during implant surgery.