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Effects of Conductive Material on $LiCoO_2$ Cathode for the Lithium ion Battery (리튬이온전지용 $LiCoO_2$ 정극의 도전재료에 따른 특성)

  • Coh Chil Hoon;Moon Seong In;Hyung Yoo Eup;Yun Mun Soo;Park Chun Jun;Yun Duk Hyun;Yun Suong Kyu
    • Journal of the Korean Electrochemical Society
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    • v.2 no.2
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    • pp.88-92
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    • 1999
  • The apparent density. self-separation of the electrode composite from current collector in the electrolyte solution and specific resistance of electronic conduction of the electrode composite were examined by the variation of content of conductive material such as graphitic and black carbons in $LiCoO_2$ composite electrode for lithium ion battery. Increasing the content of conductive material, the apparent density of Lico02 composite electrode was decreased and that of $LiCoO_2$ in composite electrode was only rapidly decreased compared to that of composite. $LiCoO_2$ composite electrodes containing more than 4.1 weight percent of super s black as a conductive material were seU-separated by the immersion into 1 mol/I $LiPF_6$ in propylene carbonate and diethyl carbonate (1:1 volume ratio). Specific resistances related to the electronic conduction of composite electrode were decreased by the increasing the content i)f conductive material. Specific resistance of the composite electrode including $2\~3\%w/w$ of super s black as conductive material was similar to that of $12\%w/w$ of Lonza KS6. In the range of this study, super s black as conductive material is better than Lonza KS6 on battery capacity because of apparent density of $LiCoO_2$ in electrode composite including super s black is higher than that of Lonza KS6.

A Relationship among Facilitating Discourse, Students' Perceived Challenge, and Learning Outcomes in an Online Science Gifted Education (온라인 영재교육에서 담화촉진, 도전감, 학습결과간의 관계)

  • Choi, Kyoung Ae;Lee, Sunghye
    • Journal of Gifted/Talented Education
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    • v.26 no.3
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    • pp.541-559
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    • 2016
  • This study investigated a relationship among facilitating discourse, students' perceived challenge, and learning outcomes(persistent intention and learning achievement) in an online science gifted education program. Two hundreds and forty-two middle school students participated in the study. A survey questionnaire which was consisted of 6 items of facilitating discourse from teaching presence questionnaire(Shea, Swan, & Pickett, 2005) and 5 items of challenge from Student Perceptions of Classroom Quality(Gentry & Owen, 2004) was administered. First, the findings of this study showed that students' perceived facilitating discourse as a part of teaching presence was positively related to students' perceived challenge in an online course. Second, students' perceived facilitating discourse were positively related to persistent intention, but were negatively related to students' achievement. Third, students' perceived challenge was positively related to persistent intention and achievement. Finally, challenge mediated the relationship between students' perceived facilitating discourse and persistent intention, and the relationship between students' perceived facilitating discourse and students' achievement as well. This results suggested that online program should be designed to increase the levels of facilitating discourse.

A Method for Challenge Placement to Set the Level of Difficulty in a Car Driving Game (자동차 주행 게임에서의 난이도 설정을 위한 도전 배치 방법)

  • Kim, Sangchul;Park, Dosaeng
    • Journal of Korea Game Society
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    • v.15 no.4
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    • pp.169-178
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    • 2015
  • Providing various levels of difficulty of game play is one of important considerations in game development. In this paper, we propose a method for obtaining the challenges that will be placed on the track of an one-player car driving game. Herein challenges denote obstacles on the track, and the level of difficulty is represented by an estimated time needed for driving one lap of the track. In the proposed method, the problem for finding challenge placement is modeled as an IP(Integer Programming) one, and then LP relaxation and Simultaneous Annealing are employed to find a solution. To the experiment with the proposed method, we can obtain challenge placements to approximately meet given target driving times. Also, after practically driving on the track where those obtained challenges are being placed, it is seen that the average driving times approximate the target driving times of those challenge placements. Our method can allow game play with various levels of difficulty so that the users' interest and the level of immerse are expected to be raised.

The effect of fun factors on re-particitation intention to traditional play: Verification of the moderating effect of challenge spirit (전통놀이 참여자들의 재미요인이 재참여의사에 미치는 영향: 도전정신의 조절효과 검증)

  • Oh, Youngtaek
    • Journal of Convergence for Information Technology
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    • v.12 no.4
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    • pp.133-142
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    • 2022
  • The purpose of this study was to verify the moderating effect of the challenging spirit on the relationship between fun factors and re-participation intentions of participants in traditional play. The subjects of this study were 164 participants in the traditional play Hanmadang contest held in Jeju Special Self-Governing Province in 2021. They measured fun factors, challenging spirit, and re-particitation intention to participate. In order to analyze the collected measurement paper, the analysis was performed using SPSS18.0, PROCESS Macro(V.2.13), Interaction program. The major results were as follows. First, the interaction between promote health and challenge spirit was found to have a significant effect on re-particitation intention at high and medium levels. Second, it was found that the interaction between the foster of social and the challenge spirit did not have a significant effect on the re-particitation intention. Third, the interaction between sense of achievement and the challenge spirit was found to have a significant effect on the re-particitation intention at the high and medium levels.

RFID 산업의 비전과 도전

  • Korea Electronics Association
    • Journal of Korean Electronics
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    • v.27 no.5
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    • pp.6-11
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    • 2007
  • 유비쿼터스 시대를 대비하여 IT 강국으로서의 노하우를 핵심역양으로 하는 RFID의 산업화에 대한 한국의 비전과 도전을 점검해본다.

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도전성 고분자 전기재료

  • 윤문수
    • 전기의세계
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    • v.37 no.3
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    • pp.4-9
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    • 1988
  • 본 란에서는 이 도전성 고분자의 연구배경과 기본적 성질, 제법 및 몇가지 응용에 대해 간략하게 소개하고, 가장 실용화에 접근해 있는 이차전지 응용에 대해 언급하고자 한다.

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벤처인이여 혁신하라,도전하라,창조하라

  • Korea Venture Business Association
    • Venture DIGEST
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    • s.69
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    • pp.12-13
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    • 2005
  • 세계적인 석학 피터 드러커는 우리나라를 기업가정신이 가장 왕성한 나라라고 칭찬한 바 있다. 하지만 국민소득 2만달러의 목전에서 겪은 외환위기, 내수침체, 청년실업난 등으로 10여 년 간 제자리걸음하고 있는 지금, 그 말이 참 무색하게 다가온다. 이 악순환의 고리를 끊기 위해 우리 경제 활성화의 견인차로 다시 벤처가 나섰다. 지금이야말로 우리 벤처인들이 위험을 무릅쓰고 포착한 기회를 사업화하려는 모험과 도전의 기업가정신으로 재무장하여야 할 때이다. 기업가정신은 돈을 벌기 위한 정신이 아니다. 주위 사람과 공동체를 중시 여겨 자기희생을 감수하는 결단이고, 상상하기 어려운 힘든 역경 속에서도 좌절하지 않고 죽을 힘을 다하는 도전이며, 탄탄대로를 거부하고 비바람 부는 날 풀이 무성한 인적 드문 길을 선택하는 모험이다. ‘자본이 없어서, 기술이 없어서, 인재가 없어서’일을 못하겠다고 조건을 탓하거나 주저하지 말자. “신에게는 아직 12척의 배가 있사옵니다”라며 백의종군하여 병사도, 배도, 무기도, 군량미도 없이 홀몸으로 대함대와 맞서 찬란한 승리를 거둔 이순신 장군을 되새겨보라. 우리 벤처인에겐 아직 혁신과 도전과 모험정신이라는 기업가정신이 있지 않은가. 하늘에 온통 구름이 끼여있고 천둥번개가 내리쳐도 여전히 구름 뒤에는 밝은 태양이 빛나고 있다. 우리 벤처인이 기업가정신을 놓지않고 이상을 위해 도전한다면, 곧 구름 뒤 태양은 모습을 드러내고, 그대 벤처인을 향해 찬란히 빛날 것이다. 벤처인이여! 벤처 재도약의 동력이 될 기업가정신으로 재무장하고, 두 발로 땅을 박차고 일어나 구름 위 이상을 향해 힘차게 도약하자.

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UHF RFID Dipole Tag Antenna Design Using Flexible Electro-Thread (도전사를 이용한 UHF RFID 다이폴 태그 안테나 설계)

  • Kim, Yeon-Ho;Chung, You-Chung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.1
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    • pp.1-6
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    • 2008
  • A wearable T-matching dipole UHF RFID tag antenna has been designed using conductive electro-thread. The conductivity of the electro-thread has been measured depending on the number of twisted thread. The measured conductivity has been used for simulation to have accurate simulation results. The flexible electro-thread or fabric has been used for fabricating the antenna instead of using copper tape since the electro-thread is more flexible and wearable than copper tape. The return loss and reading range of the fabricated electro-thread UHF RFID tag antennas have been tested. The reading range is approximately 2.4 m.

재도전 소상공인의 역량모델링에 관한 연구

  • Im, Jin-Hyeok;Park, Seong-Hui;Chae, Yeon-Hui
    • 한국벤처창업학회:학술대회논문집
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    • 2022.11a
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    • pp.59-65
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    • 2022
  • 본 연구는 코로나 팬데믹과 같은 외부 환경의 영향뿐만 아니라 경쟁 환경 및 시장변화에 적절하게 대응하지 못하는 등 역량부족의 문제로 사업 실패률이 높아진 소상공인들의 성공적인 재기를 돕고자 이들에게 요구되는 역량을 모델링하는데 목적이 있다. 이를 위해 1977년부터 2022년까지 발행된 관련 문헌을 분석하였고 7인의 재도전 소상공인을 대상으로 행동사건인터뷰(BEI)를 진행하였으며, 역량개발 및 HRD 전문가를 섭외하여 세 차례에 걸처 초점집단인터뷰(FGI)를 실시하는 과정을 통해 역량초안을 도출하였다. 이를 바탕으로 12명의 관련분야(창업, 소상공인, 심리/역량) 전문가를 섭외하여 3회에 걸친 델파이기법(Delphi Analysis)을 통해 재도전 소상공인의 성공적인 재기에 도움이 되는 역량을 2개의 역량군(소상공인, 실패회복), 8개의 세부역량(사업기회포착, 사업기획, 사업차별화, 운영관리, 판로개척, 제품과 서비스 연구개발, 긍정적 자기조절, 실패경험 극복 및 대처), 22개의 역량요소, 72개의 지식·기술·태도(KSA)가 표시된 행동지표로 도출하였다. 이와 같이 진행된 본 연구는 국내 최초로 재도전 소상공인에게 요구되는 역량을 구체화했다는데 학술적 의미가 있다. 또한 본 연구 결과는 재도전 소상공인 대상 역량기반 교육프로그램을 개발하거나 지원 프로그램에 적합한 대상자 선별하는 등에서 활용될 수 있으며 소상공인 스스로 사업 성공을 위해 역량을 진단하며 자기개발을 촉진하는데 활용할 수 있을 것으로 보인다.

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Quantitative Conductivity Estimation Error due to Statistical Noise in Complex $B_1{^+}$ Map (정량적 도전율측정의 오차와 $B_1{^+}$ map의 노이즈에 관한 분석)

  • Shin, Jaewook;Lee, Joonsung;Kim, Min-Oh;Choi, Narae;Seo, Jin Keun;Kim, Dong-Hyun
    • Investigative Magnetic Resonance Imaging
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    • v.18 no.4
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    • pp.303-313
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    • 2014
  • Purpose : In-vivo conductivity reconstruction using transmit field ($B_1{^+}$) information of MRI was proposed. We assessed the accuracy of conductivity reconstruction in the presence of statistical noise in complex $B_1{^+}$ map and provided a parametric model of the conductivity-to-noise ratio value. Materials and Methods: The $B_1{^+}$ distribution was simulated for a cylindrical phantom model. By adding complex Gaussian noise to the simulated $B_1{^+}$ map, quantitative conductivity estimation error was evaluated. The quantitative evaluation process was repeated over several different parameters such as Larmor frequency, object radius and SNR of $B_1{^+}$ map. A parametric model for the conductivity-to-noise ratio was developed according to these various parameters. Results: According to the simulation results, conductivity estimation is more sensitive to statistical noise in $B_1{^+}$ phase than to noise in $B_1{^+}$ magnitude. The conductivity estimate of the object of interest does not depend on the external object surrounding it. The conductivity-to-noise ratio is proportional to the signal-to-noise ratio of the $B_1{^+}$ map, Larmor frequency, the conductivity value itself and the number of averaged pixels. To estimate accurate conductivity value of the targeted tissue, SNR of $B_1{^+}$ map and adequate filtering size have to be taken into account for conductivity reconstruction process. In addition, the simulation result was verified at 3T conventional MRI scanner. Conclusion: Through all these relationships, quantitative conductivity estimation error due to statistical noise in $B_1{^+}$ map is modeled. By using this model, further issues regarding filtering and reconstruction algorithms can be investigated for MREPT.