열수처리에 의해 석출된 HA 결정이 Ti-6Al-7Nb 합금의 생체활성에 미치는 영향

권오성,최석규,문장원,이민호,배태성,이오연,Kwon O. S.,Choi S. K.,Moon J. W.,Lee M. H.,Bae T. S.,Lee O. Y. 한국재료학회 2004 한국재료학회지 Vol.14 No.9

This study was to investigate the surface properties of electrochemically oxidized Ti-6Al-7Nb alloy by anodic spark discharge technique. Anodizing was performed at current density 30 $mA/cm^2$ up to 300 V in electrolyte solutions containing $DL-{\alpha}$-glycerophosphate disodium salt hydrate($DL-{\alpha}$-GP) and calcium acetate (CA). Hydrothermal treatment was done at $300^{\circ}C$ for 2 hrs to produce a thin outermost layer of hydroxyapatite (HA). The bioactivity was evaluated from HA formation on the surfaces in a Hanks' solution with pH 7.4 at $36.5^{\circ}C$ for 30 days. The size of micropores and the thickness of oxide film increased and complicated multilayer by increasing the spark forming voltage. Needle-like HA crystals were observed on anodic oxide film after the hydrothermal treatment at $300^{\circ}C$ for 2 hrs. When increasing $DL-{\alpha}$-GP in electrolyte composition, the precipitated HA crystals showed the shape of thick and shorter rod. However, when increasing CA, the more fine needle shape HA crystals were appeared. The bioactivity in Hanks' solution was accelerated when the oxide films composed with strong anatase peak with presence of rutile peak. The increase of amount of Ca and P was observed in groups having bioactivity in Hanks' solution. The Ca/P ratio of the precipitated HA layer was equivalent to that of HA crystal and it was closer to 1.67 as increasing the immersion time in Hanks' solution.

열수처리 시간에 따른 Ti-6Al-7Nh 합금의 생체활성 평가

권오성,최석규,박광범,이민호,배태성,이오연,Kwon O. S.,Choi S. K.,Park K. B.,Lee M. H.,Bae T. S.,Lee O. Y. 한국재료학회 2004 한국재료학회지 Vol.14 No.12

This study was to investigate whether the bioactivity of the anodized and hydrothermally treated Ti-6Al-7Nb alloy were affected by the time of hydrothermal treatment. Anodizing was performed at current density 30 $mA/cm^2$ up to 300 V in electrolyte solutions containing $DL-{\alpha}-glycerophosphate$ disodium salt hydrate $(DL-{\alpha}-GP)$ and calcium acetate (CA). Hydrothermal treatment was done at $300^{\circ}C$ for 30 min, 1 hr, 2 hrs, and 4 hrs to produce a thin film layer of hydroxyapatite (HA). The bioactivity was evaluated from HA formation on the surfaces in a Hanks' solution with pH 7.4 at $36.5^{\circ}C$ for 10, 20, and 30 days. Anodic oxide films were porous with pore size of $1\sim4{\mu}m\;and\;3\sim4{\mu}m$ thickness. The anodic oxide films composed with strong anatase peak with presence of rutile peak, and showed the increase in intensity of anatase peak after hydrothermal treatment. It was shown that the intensity of anatase peak increased with increasing the time of hydrothermal treatment but was no difference in rutile peak. The corrosion voltage was the highest in the group of hydrothermal treatment for 2 hrs (Ecorr: -338.6 mV). The bioactivity in Hank's solution was accelerated with increasing the time of hydrothermal treatment.

로봇용 연료전지 이차전지 하이브리드 시스템 연구

권오성,이상철,이상우,이동하,Kwon, O-Sung,Lee, Sang-Cheol,Lee, Sang-Woo,Lee, Dong-Ha 한국태양에너지학회 2012 한국태양에너지학회 논문집 Vol.32 No.suppl3

Proton exchange membrane fuel cell (PEMFC) is the most promising energy source for the robot applications because it has unique advantages such as high energy density, no power drop during operating, and easy to make compact size. However, PEMFC has intrinsic disadvantages which are delay to start up and difficulty to correspond drastic load changes. These disadvantages can be compensated by hybrid operating with a Li-poly battery. This study is focus to build and understand the hybrid system for the robot system. In this study, we build the PEMFC hybrid system using EOS-320 PEMFC stack, Li-poly battery and G-Philos FDX1-250BU dc-dc converter. The hybrid system is accurately monitored by CAN and RS485. The system was studied under two conditions such as non-loaded and loaded operating conditions. The results show that the system has delay to start up without hybrid operating and it can be compensated with the hybrid operating.

치료적 마사지와 근재교육 훈련이 안면신경마비 환자의 회복에 미치는 영향

권오성,김선엽,오덕원,김진섭,Kwon, Oh-Sung,Kim, Suhn-Yeop,Oh, Duck-Won,Kim, Jin-Seop 대한물리치료과학회 2009 대한물리치료과학회지 Vol.16 No.1

Background: The purpose of this study was to determine the effect of massage and muscle reeducation training with conventional treatment in patients with facial paralysis. Methods: Twenty-five patients with facial nerve paralysis were randomly allocated to 3 groups: massage, muscle reeducation training, and control groups. Therapeutic intervention for the massage (n=8) and muscle reeducation training (n=8) groups consisted of conventional therapy such as application of hot pack and electrical stimulation plus massage therapy and muscle reeducation training, respectively. The control group (n=9) received only conventional therapy. Therapeutic intervention for each group was performed 6 times per week for 4 weeks. The patients were assessed by using the House-Brackmann Grading System (H-B grade) and Yanagihara Unweighted Grading System (Y grade) once every week. Results: The H-B and Y grades improved significantly in all 3 groups after a 4-week intervention (p<.01). At 3 and 4 weeks, the H-B and Y grades of the massage group improved significantly when compared with those of the control group (p<.01). Muscle reeducation training group showed significant improvements in the scores of the two grades with time when compared with the massage and control groups (p<.01). The rate of change in the H-B grade was significantly different between the control and muscle reeducation training groups (p<.01), and that of change in the Y grade was significantly different between the control and muscle reeducation training groups (p<.01) and between the control and massage groups (p<.01). Conclusion: These findings suggest that massage and muscle reeducation training are more effective in improving the condition of patients with facial nerve paralysis than conventional therapy. In particular, the results of this study indicate that muscle reeducation training can be recommended by clinicians since it provides more benefits.

지식 축적과 AI 기술을 기반으로 한 인류 역사 모형

권오성,Kwon, Oh-Sung 한국정보교육학회 2021 정보교육학회논문지 Vol.25 No.5

21세기 인류는 AI 실용 시대를 열어 가고 있다. 이제껏 인류는 산업 구조가 고도화 되어도 지식 생산의 추상화 작업 만큼은 자신의 고유 영역이라 보았는 데 그 믿음에 의구심을 갖게 되었고, 이에 현대인은 인간과 기계 지능을 구분하고 자신의 정체성을 새롭게 구축해야 하는 상황에 놓이게 되었다. 이에 본 논문은 현대 인류의 정체성을 과거로부터 축적한 지식의 결과라는 관점에서 살피고자 하였다. 이러한 논의를 지구와 인류 출현으로부터 시작하는 "단계별 지식 축적 방식의 변화" 라는 역사 모형으로 요약하여 제시하였다. 이 분석 모형의 1 단계는 지구 상에 인간 지능 출현까지의 "DNA 지식 축적" 이다. 2단계는 스스로 지식을 생산할 수 있게 된 인간의 생물학적 지능에 의한 "문명 지식 축적" 과정이다. 현재는 3단계로 분류되며 AI 기술을 이용한 "기계적 지식 축적"단계로 진입하고 있다고 보았다. 본 논문은 인류 역사를 이러한 단계별 지식 축적 모형으로 제안하며 관련한 논의를 기술하였다. Humanity in the 21st century is ushering in an era of practical use of AI. Until now, even though the industrial structure has been advanced, mankind has seen that the abstraction of knowledge production is only their own domain, but they have doubts about that belief. Therefore, this paper tried to examine the identity of modern humanity from the perspective of the result of knowledge accumulated from the past. These discussions were summarized and presented in a historical model called "Changes in the way of accumulating knowledge step by step" starting from the emergence of the earth and mankind. The first stage of this analytical model is the "accumulation of DNA knowledge" until the emergence of human intelligence on Earth. The second stage is the process of "accumulating civilized knowledge" by human biological intelligence, which has become capable of producing knowledge on its own. It is currently classified into three stages and it is considered that it is entering the stage of "accumulating mechanical knowledge" using AI technology. This paper proposes human history as such a step-by-step knowledge accumulation model and describes related discussions.

ASEAN 진출대상국의 IT 정책과 인프라 분석

권오성,Kwon, Oh-Sung 한국정보기술전략혁신학회 2003 情報學硏究 Vol.6 No.4

In the era of so-called knowledge-based economy, the creation and utilization of IT and new knowledge are recognized as core factors to enforce IT industry and to increase national competitiveness. Advanced countries, therefore, have heavily invested their resources on IT sector and introduced competition into the telecommunication market. ASEAN countries are trying to make themselves informationized society through IT market liberalization and industry development. They are investing lots of resources to construct IT infrastructure such as wired and wireless network and consider informationized society promotion as top national agenda. In this effort, Korea is a benchmarking model for them. Successful entering into ASEAN market requires close analysis and correct understanding of its IT policy and infrastructure. In this paper, therefore, tried to analyse IT policy and infrastructure of three ASEAN countries, which have high potential of economic cooperation in IT with Korea. And based on the analysis, tried to find out ways to enter into ASEAN.

Hong-Ou-Mandel 간섭계를 이용한 Bell 상태

권오성,김헌오,박구동,김태수,Kwon, O-Sung,Kim, Heon-Oh,Park, Gu-Dong,Kim, Tae-Soo 한국광학회 2007 한국광학회지 Vol.18 No.1

제 1형의 매개하향변환에서 발생하는 광자쌍과 Hong-Ou-Mandel 간섭계를 이용하여 편광-얽힘 상태의 광자쌍을 선택적으로 발생시키고, 반파장판과 4분파장판을 조합하여 4개의 Bell 상태 $|{\Psi}^{\pm}>,|{\Phi}^{\pm}>$를 구현하였다. 동시계수 측정에 의한 각 상태의 평균 선명도는 77%이다. Bell states have been investigated in a Hong-Ou-Mandel interferometer using photon pairs from a type-1 SPDC. The four kinds of the Bell states, $|{\Psi}^+>,|{\Psi}^->,|{\Phi}^+>,|{\Phi}^->$ are created by placing 2 HWPs, 2 QWPs at outputs of the interferometer. They show an average visibility of 77% in the coincidence measurement.

플라즈마 중합 처리된 중공사 막의 혈액 적합성

권오성,이삼철,Kwon O. S.,Lee S. C. 한국재료학회 2005 한국재료학회지 Vol.15 No.8

Surface modification of polypropylene hollow fiber membranes was peformed in order to develop blood-compatible biomaterials for use in the blood contacting and oxygenation membranes of a lung-assist device(LAD). Blood compatibility was determined by using anticoagulation blood and evaluating formation of blood clots on their surfaces as well as activation of plasma coagulation cascade, platelet adhesion, and aggregation. It was verified that the number of platelets on the silicone coated fibers was significantly lower than those on polypropylene. It was also found that the polypropylene hollow fiber membranes using plasma treatment exhibited suppression of complement activation in blood compatibility test.

한글 자소의 필기 특징 분석

권오성,Kwon, Oh-Sung 한국정보교육학회 2001 정보교육학회논문지 Vol.4 No.2

For the efficient teaching of Korean characters(Hangul) handwriting method, it needs to the collection of Hangul handwriting samples and the study of analysis methods. For the collection of Hangul handwriting samples, the students of teacher's university take part in this survey. The analysis is performed according to the characters and graphemes in Hangul. The analysis features include the number of strokes, the direction of handwriting, the relational position of graphemes, the height and width of characters, and so on. The results of this analysis will be used for the reference data for the teaching of Hangul handwritings, the study of Hangul fonts, and the research of Hangul information engineering.

온도하중에 의한 버팀보 축력증가 대책사례

권오성,이종성,Kwon, Oh-Sung,Lee, Jong-Sung (사)한국토질및기초기술사회 2006 기술발표회 Vol.2006 No.-

서울지하철 0호선 000 공구 000 정거장 구간은 버팀보 7단, 어스앵커 2단, 그리고 록볼트 3단의 개착식 가시설로 설계되어 있다. 버팀보 및 앵커 축력 계측을 위해 변형률계 및 하중계를 설치하고 연속계측 중, 4~6단 버팀보 수 개소에서 5월부터 하중이 급격히 증가하엿다. 따라서 굴착작업을 즉시 중단하고 관리기준치를 초과하는 하중이 계측된 STA.9k+750~800 구간의 5, 6단 버팀보 위치에 격간으로 총 20본(10본${\times}$2단), 그리고 STA.9k+900~920 구간의 7단 버팀보 위치에 격간으로 총 9본(9본${\times}$1단)의 버팀보를 추가적으로 설치 완료하였다. 이 때, 추가 버팀보는 선행하중잭을 이용하여 10ton의 선행하중을 재하하였으며, 향후 추가 보강 필요시 재하하중 증가가 가능하도록 조치하였다. 또한, 추가 설치된 버팀보, 그리고 이상하중이 발생된 버팀보에 계측기를 추가 설치하여 지속적으로 계측중이며, 띠장의 변위발생 구간은 스티프너 및 앵글 등을 응급조치하였다. 본 사례 연구에서는 보강 전.후의 계측결과 및 수치해석적 분석을 이용하여 가시설 굴착시 버팀보의 하중증가 원인 및 보강 효과를 규명하고, 향후 추가 굴착시의 안정성 여부를 검토해 보고자 하였다. 계측값 분석 결과, 추가버팀보 보강 후의 기존버팀보 축력 계측 결과 보강 직후 기존버팀보의 축력이 어느정도 감소하였으며, 이후 시간이 지남에 따라 축력이 더 이상 증가하지 않고 일정한 값에 수렴하는 경향을 보였다. 또한 수치해석 결과 온도 증가가 버팀보 축력증가에 미치는 영향은 버팀보 위치의 지반강성이 클수록 크며, 축력증가는 온도증가에 대체적으로 비례하였고, 추가버팀보의 보강 효과는 선행하중의 크기에 비례하는 것으로 나타났으며, 잔여굴착은 전반적으로 기존 버팀보의 축력 증가에 영향을 미치는 것으로 나타났다. 따라서 추가굴착시 지속적인 계측을 수행하며, 급격한 축력증가가 관찰될 경우 현재 보강된 버팀보의 선행하중 추가 재하, 굴착에 가장 큰 영향을 받는 최하단 버팀보의 추가보강 등의 대책방안을 제시하였다.