다양한 산화물들이 리튬규산염 유리의 결정화에 미치는 영향

김철민,임형봉,김용수,김세훈,오경식,김철영,Kim, Chul-Min,Lim, Hyung-Bong,Kim, Youg-Su,Kim, Se-Hoon,Oh, Kyung-Sik,Kim, Cheol-Young 한국세라믹학회 2011 한국세라믹학회지 Vol.48 No.4

Glass-ceramics based on lithium disilicate($Li_2Si_2O_5$) are prepared by heat-treatment of glasses in a system of $SiO_2-Li_2O-K_2O-Al_2O_3$ with different compositions. The crystallization heat-treatment was conducted at the temperature range of $700{\sim}900^{\circ}C$ and samples were analyzed by XRD and SEM. Mechanical properties were determined by a Vicker's hardness and 4 point bending strength. When $SiO_2/Li_2O$ ratio increased, cristobalite and tridymite crystals showed more predominate than lithium disilicate crystals. Increase in $Al_2O_3$ contents in the glass suppressed crystallzation of lithium disilicate crystals. Increase in ZnO, $B_2O_3$ contents in the glass decreased crystallization temperature of lithium disilicate crystals, and increased mechanical properties because of the reduction of the lithium disilicate crystal size.

화물자동차 운송정보망 구축에 관한 탐색적 연구

김철민Chul-Min Kim) 한국국제상학회 2010 國際商學 Vol.25 No.2

Domestic cargo trucking transportation service industry has been suffering from too much excessive supply and one of the reasons was the unadequate government policy. 'This hard environment causes truck drivers' transportation veto from 2003 and serious danmge to the Korean economy. Recently, the proposition of a cargo trucking service transportation law which is submitted to the Korea national assembly in 2009 can be an effective alternative for the innovation of the old and inefficient cargo trucking transportation industry. According to the above law proposition, trucking company and trucking mediation agencies should use the cargo trucking information networking system which can be cargo trucking franchise companies or information systems certified by the Korean government. This research compared the needs for the trucking information networking system among truck drivers, trucking and service mediating agencies, and forwarders by the survey methodology. Research results suggest tllat the information networking system should be developed by the regional base, not the whole country base. Survey research also suggests tllat the various trucking transportation associations in Busan should participate in the developing and operating of the new system

원인 불명의 실신 환자의 진단에 있어서 Head - up tilt Test 의 유용성과 혈관미주신경성 실신 환자의 임상적 특징

윤호중(Ho Joong Youn),정욱성(Wook Sung Chung),백상홍(Sang Hong Baek),김철민(Chul Min Kim),박인수(In Soo Park),김재형(Jae Hyung Kim),최규보(Kyu Bo Choi),홍순조(Soon Jo Hong) 대한내과학회 1994 대한내과학회지 Vol.47 No.2

Background: Syncope, defined as a transient loss of consciousness, is a frequently encountered symptom, but despite thorough clinical and invasive diagnostic investigation, the cause of syncope remains unexplained. In recent years, head-up tilt test has been of increasing interest as a diagnostic aids in patients with unexplained syncope. We studied to define the usefulness of various diagnostic test in the evaluation of patients with recurrent syncope, to assess the usefulness of head-up tilt test in the working of syncope of unknown origin and to evaluate the clinical characteristics of subgroups of patients with syncope induced by head-up tilt test. Methods: Between June, 1991 and November, 1992 at St. Mary`s hospital, 21 patients with history of syncope and 24 control subjects without history of syncope underwent 60° head-up tild test for 60 min. Results: 1) The definite cause for recurrent syncope were diagnosed in 10 of patients (47,6%) after clinical and invasive tests. 2) During head-up tilt test, vasovagal responses were provoked in 5 of 21 patients (23.8%) with recurrent syncope and 1 of 24 patients (4.2%) without syncope (p<0,05). 3) The head-up tilt test induced symptomatic bradycardia or hypotension in 3 of 10 patients (30%.) with negative electrophysiologic results. 4) During tilt induced vasovagal response, a) mean heart rate decreased to 42±24 beat/min from supine control of 70±12 beat/min (p<0. 05), b) mean systolic blood pressure decreased to 95±12 mmHg from supine control of 120±S mmHg (p<0,05), c) mean diastolic blood pressure decreased to 60±21mmHg from supine control of 72±13 mmHg (p<0.05), d) the time interval to onset of vasovagal response was 22±12 min. Conclusions: 1) In a large proportion of patients with recurrent syncope, the diagnosis remains unexplained despite a neurologic and cardiologic investigation including an electrophysiologic study. 2) Vasovagal responses are frequent cause in patients with recurrent unexplained syncope. 3) The head-up tilt test may be a simple, safe and highly yielding provocative test in the investigation of syncope of unknown origin.

시뮬레이션을 통한 압전형 초음파 스케일러 개발 및 평가

김철민,이영진,백종후,정영훈,강국진,이정배,이승대,Kim, Chul-Min,Lee, Young-Jin,Paik, Jong-Hoo,Jeong, Young-Hun,Kang, Kook-Jin,Lee, Jeong-Bae,Lee, Seung-Dae 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.10

A piezoelectric ultrasonic scaler, usually used to remove the tartar out of teeth and to amputate the pubis, is a recently popular instrument for dental treatment due to its several merits such as small size, low-electric power, precision and low-cost. It has typically two parts of a tip and vibration system, which is also composed of head, piezoelectric elements and tail-mass. The scaler concentrates its displacement on tip and has commonly a resonance frequency at 25~30 kHz, and in order to improve the performance of the scaler, it is important to standardize the size of the vibration system without tip for high performance because scaler in quality differs according to several tips. In this study, a Finite Element Analysis (FEA) was utilized to optimize the structure of ultrasonic scaler in the vibration system. Consequently, this study revealed that influence of several tips on property were minimized and scaler showed good property at the resonance frequency of 28 kHz.

MPEG-2 비디오 디코더 적합성 검사용 비트열의 제작

김철민,이병욱,박래홍,Kim, Chul-Min,Lee, Byung-Uk,Park, Rae-Hong 대한전자공학회 1999 電子工學會論文誌, S Vol.s36 No.10

MPEG-2 비디오 표준에서는 다양성을 보장하기 위하여 많은 변수들을 조절할 수 있다. MPEG-2 비트열을 통하여 전송되는 이러한 변수들이 MPEG 비디오 디코더에서 올바르게 해석되어, 전송한 것과 동일한 영상이 수신기에서 재생되는지 확인하여야 한다. 본 논문에서는 검사할 디코더의 최정화면을 관측하여 MPEG 비디오 디코더의 정상 동작 여부를 간편하게 확인할 수 있도록 검사용 비트열을 설계하는 방식을 제안하였다. 제작된 비트열의 내부는 두 부분으로 구성된다. 하나는 검사할 변수를 변화시키며 검사 패턴을 만드는 부분이고, 다른 하나는 MPEG의 움직임 보상과 discrete cosine transform(DCT) 계수를 이용하여 이전 프레임에서 만들어진 검사 패턴을 상쇄시키는 부분이다. 이러한 원리를 적용하여 검사용 비트열을 제작하였고 스프트웨어 디코더로 분석한 결과를 제시하였다. In MPEG-2 video standard, there are many parameters to support profiles and levels. It is necessary to verify that a decoder is compliant with the MPEG-2 standard. This paper proposes a design principle of the test bitstreams which confirms that an MPEG video decoder is correct by observing the final image of the decoder under test. The presented test bitstream is composed of two parts. The first part generates a test pattern by varying a selected test parameter. And the following predictive coded picture generates a complementary pattern to the previous image by motion compensation and DCT coefficients. Then it will result in a uniform pattern. We present several bitstreams following the proposed principle. Also we analyze and compare the characteristics of the test bitstreams presented in the MPEG conformance test and the proposed test bistreams.

제2차 세계대전과 유고슬라비아

김철민,Kim, Chul Min 한국외국어대학교 외국학종합연구센터 동유럽·발칸연구소 2000 동유럽발칸연구 Vol.8 No.-

한국전쟁에서 유고슬라비아의 역할과 그 의미 (1)

김철민(Chul-Min Kim) 아시아·중동부유럽학회 2001 동유럽발칸학 Vol.3 No.1

In this study, such as basis for study about “Yugoslavia's role and meaning in Korean War”, at first I will analyze about “Yugoslavia's Understanding and Action about Korean Problem before Korean War in UN”. After Cominform dispute(1948), in the political situation which has been enlarged Soviet and its bloc's open military hostilities, Yugoslavia tried to maintain its independence and territory. At that time, dispute about Korean problem in UN for Korea's future has been received as good chance to Yugoslavia. Yugoslavia tried to show its will and intension for sovereignty-protection and foreign policy (which will not participate in any block.) to the members in UN with participation in dispute of Korean problem. Yugoslavia sometimes applied Korean problem in UN with its foreign strategy. Yugoslavia was always afraid of Soviet and its bloc's invasion by military power after Cominform conflict. So, Korean War has received as very important international occasion to Yugoslavia. Yugoslavia conceived Korean War as a collision between the West and the East, and started to analyze why occurred this collision in Korean peninsula instead of Balkan (Yugoslavia) which has been understood as peak of the Cold War. In this study, for understanding about background of Korean War, I will explain process of division Korean peninsula and about a failure of Moscow's agreement(Chapter II). In Chapter III, I will analyze how Yugoslavia understood about Korea and Korean problem, and how acted about Korean problem in UN with which foreign strategy before Korean War. Finally as a conclusion (Chapter IV), I will summarize about background of Yugoslavia's interest about Korean problem, and will explain about meaning of Korean War in Yugoslavia.

체육진로 교육자의 ‘경기꿈의대학’ 비대면 수업 운영에 관한 자문화기술지

김철민(Chul-Min Kim),최덕묵(Duk Mook Choi) 한국홀리스틱융합교육학회 2022 홀리스틱융합교육연구 Vol.26 No.2

본 연구는 경기꿈의대학 체육관련 강좌를 운영하는 진로교육자가 비대면 수업운영의 어려움과 개선해나가는 변화의 과정을 연구자의 관점에서 탐색하는데 목적이 있다. 이에 본 연구의 참여자는 수업을 운영하는 교수자인 ‘나’이다. 이를 위해 자문화기술지 연구 방법으로 수업 현장을 생생하게 들여다보며 교수자와 학생들이 보여주는 다양한 상황에서 교육적 의미를 찾기 위해 노력하였다. 연구자료는 교수자가 수업을 운영하고 개선방안을 모색하기 위해 작성한 수업일지와 자기회상일지를 사용하였다. 자료분석은 Spradley(1979)의 영역분석과 분류분석 방법을 활용하였다. 연구결과, 첫째, 학생들은 수업 중 카메라를 켜지 않고, 소극적인 행동을 보이고, 다른 무엇인가에 집중하고, 학생부 기록을 위해 참여하며 수업에 관심이 없었다. 둘째, 학생들의 수업 참여를 이끌기 위하여 수업에 변화를 주었다. 구체적으로, 학생들의 의견을 반영하여 학습주제 선정하기, 텍스트와 보이스를 활용하며 자유롭게 소통하기, 인터넷을 활용한 흥미로운 학습활동 제시하기, 그리고 학생들의 유능감 높여주기를 실시하였다. 이로 인해 셋째, 학생들은 닫혀있던 마음을 열고 수업에 참여하며 체육에 대한 지식을 습득하고 진로에 대한 안목을 형성할 수 있었다. 이에 따라 경기꿈의대학 체육진로 교육의 발전을 위한 제도 및 실천력 강화, 교수자의 비대면 교육 역량 높이기, 다양한 체육진로교육 연구의 필요성을 제안하였다. The purpose of this study is to explore the difficulties and improvement process of teachers who operate non-face-to-face physical education classes at Gyeonggi Dream University. The participant in this study is 'I', the instructor. I used the autoethnography methodology to discover educational meaning in the class.. For the research, self-recovery diary and reflective journal collected. Data analysis were used Spradley(1979)'s area and classification analysis method. As a result of the study, first, students did not turn on the camera during class, showed passive behavior, focused on something else, participated in the class for student record, and were not interested in the class. Second, the class was changed to lead students to participate in the class. It was ducted to select a learning topic by reflecting students' opinions, to communicate freely using text and voice, to present interesting learning activities using the Internet, and to increase students' competence. Third, students opened their closed minds and participated in classes to acquire knowledge of physical education and learn about their careers. Accordingly, the necessity of strengthening the physical career education system and practical ability of Gyeonggi Dream University, enhancing the non-face-to-face education competency of instructors, and research on physical education was proposed.

육상화물운송산업의 e-마켓플레이스 도입실태

김철민(Kim, Chul-Min),정석찬(Jeong, Seok-Chan) 국제e-비즈니스학회 2005 e-비즈니스 연구 Vol.6 No.2

가상 해저 시뮬레이션의 현실감 향상을 위한 다감각 효과 재현 시스템 개발 및 평가

김철민(Cheol-Min Kim),윤재홍(Jae-Hong Youn),강임철(Im-Chul Kang),김병기(Byung-Ki Kim) 한국멀티미디어학회 2014 멀티미디어학회논문지 Vol.17 No.1