THERRESTRIAL IMPACT CRATERING CHRONOLOGY: A PRELIMINARY ANALYSIS

Moon, Hong-Kyu,Mi, Byung-Hee,Fletcher, Andre-B.,Kim, Bong-Gyu The Korean Space Science Society 2001 Journal of Astronomy and Space Sciences Vol.18 No.3

We have recently compiled a database of the properties of 192 impact craters, which supercedes previous compilations. Using our database, the impact structures found in North America, Europe and Australia have been examined; these cratonic areas have been relatively stable for considerably long geological periods, and thus have been best preserved. It is confirmed that there is a close correlation between the geological epoch boundaries, the epochs of mass extinctions, antral the "timing" of impacts. In addition, the terrestrial cumulative flux of objects >20km is found to be $1.77{\times}10^{-15}km^{-2}yr^{-1}$, over the last 120 Myr, which is much smaller than the published values in McEwen et al. (1997) and Shoemaker (1998) ($5.6{\pm}2.8{\times}10^{-15}km^{-2}yr^{-1}$. For terrestrial impact structures with D> 50 km, the apparent cumulative flux over the last 2450 Myr is ~50 times smaller than the corresponding value for the Moon. If we assume that the Earth and the Moon suffered the same level of bombardment over this time, this would mean that the actual flux of impacting bodies, capable of making craters with D)50 km, was ~ 50 times larger than the apparent flux estimated from the currently known terrestrial records.

Korea Pathfinder Lunar Orbiter (KPLO) Operation: From Design to Initial Results

Moon-Jin Jeon,Young-Ho Cho,김은혁,Dong-Gyu Kim,Young-Joo Song,홍승범,Jonghee Bae,Jun Bang,Jo Ryeong Yim,Dae-Kwan Kim 한국우주과학회 2024 Journal of Astronomy and Space Sciences Vol.41 No.1

Korea Pathfinder Lunar Orbiter (KPLO) is South Korea’s first space exploration mission, developed by the Korea Aerospace Research Institute. It aims to develop technologies for lunar exploration, explore lunar science, and test new technologies. KPLO was launched on August 5, 2022, by a Falcon-9 launch vehicle from cape canaveral space force station (CCSFS) in the United States and placed on a ballistic lunar transfer (BLT) trajectory. A total of four trajectory correction maneuvers were performed during the approximately 4.5-month trans-lunar cruise phase to reach the Moon. Starting with the first lunar orbit insertion (LOI) maneuver on December 16, the spacecraft performed a total of three maneuvers before arriving at the lunar mission orbit, at an altitude of 100 kilometers, on December 27, 2022. After entering lunar orbit, the commissioning phase validated the operation of the mission mode, in which the payload is oriented toward the center of the Moon. After completing about one month of commissioning, normal mission operations began, and each payload successfully performed its planned mission. All of the spacecraft operations that KPLO performs from launch to normal operations were designed through the system operations design process. This includes operations that are automatically initiated post-separation from the launch vehicle, as well as those in lunar transfer orbit and lunar mission orbit. Key operational procedures such as the spacecraft’s initial checkout, trajectory correction maneuvers, LOI, and commissioning were developed during the early operation preparation phase. These procedures were executed effectively during both the early and normal operation phases. The successful execution of these operations confirms the robust verification of the system operation.

선물환시장을 이용한 환위험관리 : 이변량 ECT-ARCH(1)모형을 중심으로

문규현,-- 한국금융학회 2003 金融學會誌 Vol.8 No.2

본 연구에서는 국내선물환(Forwards)을 이용한 원·달러현물환율 변동위험에 대한 헤지성과를 분석하였으며 주요 연구결과는 다음과 같다. 첫째, 최적헤지비율 추정결과, 최소분산헤지비율 및 이변량 ECT-ARCH(1) 모형 모두 기간이 짧은 원·달러선물환율들의 헤지비율이 기간이 긴 원·달러선물환율을 이용한 헤지비율보다는 상대적으로 높은 것으로 나타났으며, 시간변동최적헤지모형이 최소분산 헤지모형이 헤지비율보다 상대적으로 높은 것으로 나타났다. 둘째, 헤지모형별 헤지성과 분석결과에 의하면, 내표본(within-sample) 및 외표본(out-of-sample)기간 모두 헤지비율이 시간이 경과함에 따라 변화하는 이변량 ECT-ARCH(1) 모형 및 이변량 ARCH(1)의 헤지성과가 단순헤지모형과 헤지비율이 일정한 것으로 가정하는 전통적 헤지모형인 최소분산헤지모형(minimum variance hedging model)보다 상대적으로 더 나은 것으로 나타났다. 셋째, 각 기간별 원·달러선물환의 헤지성과 분석 결과, 환율변동에 따른 원·달러 현물가격변동 위험을 헤지하기 위해서는 장기적인 원·달러선물환보다는 단기 선물환율을 이용한 헤지성과가 상대적으로 더 나은 것으로 나타났다. 따라서 우리나라 원·달러외환시장의 경우 단순헤지모형과 전통적인 최소분산헤지모형보다는 시간변동 최적헤지모형을 이용하는 것이 더 바람직한 헤지성과를 얻을 수 있으며, 장기보다는 3개월 미만의 단기선물환을 이용하는 것이 상대적으로 나은 결과를 보였다. This paper studies hedging strategies that use the Won-dollar forwards to hedge the price risk of the Won-dollar exchange rate. This study uses the minimum variance hedge model and bivariate ECT-ARCH (1,1) model as hedge models, and analyzes their hedge performances. The sample period covers from March 1, 2002 to March 31, 2003 with 7 sub-samples such as 1week, 1month, 3months, 6months, 9months, and 1year. The most important findings may be summarized as follows. First, the hedge ratios of short periods in 3months are relatively higher than those of long periods above 3months. Hedge ratios of the ECT-ARCH (1) tend to be higher than those of risk-minimization model. Second, for both the in-sample data and the out-sample, hedging effectiveness of ARCH (1) and ECT-ARCH (1) model is higher than that of the risk-minimization with constant hedge ratios. Third, the hedge effectiveness of short periods consistently tend to be higher than that of long periods. In conclusion, investors are encouraged to use the time varying hedge models like ARCH, ECT-ARCH model rather than simple risk-minimization model to hedge Won-dollar exchange rate with short periods forwards within 3months.

消化性潰瘍의 治法 및 運治方 活用에 對한 考察

文九,林圭庠,崔賢 圓光大學校 漢醫科大學 1989 圓光漢醫大論文集 Vol.- No.6

After finding out cure-all method by analyzing and synthesizing of Peon-Zheng-Shi-Chi(辨證施治) and clinical character of peptic ulcer, forming a cure-all prescription, attempting to conform the modificatory method of Kun(monarch). Shin(minister). Zhoa(assistant). Sha(guide) of forming drugs by Peon-Zheng(辨證) and modificatory drugs with Peon-Zheng-Shi-Chi(辨證施治) of Oriental medicine and pharmacologic effect of Western medicine, the author obtained conclusion as below. 1. The cure-all method based on the method of Peon-Zheng-Shi-Chi(辨證施治) are So-Kan-Hai-Wul (疏肝解鬱), Hoa-Wei (和胃), Hoal-Heol-Sang-ki (活血生肌), Hai-Keong-Zhin-Tong (解痙鎭痛), Jhei-San(制酸)(antacid). 2. The forming drugs of cure-all prescripiton are Radix paeoniae, Radix Glycyrrhizae, Rhizoma Cyperi, Radix Aucklandiae, Radix Linderae, Rhizoma Atracyodis, Pericarpium Citri Reticulatae, Cortex Magnoliae Officinalis, Os Sepiae, Rhizoma Corydalis, Resina Myrrhae, Radix Astragali, Radix Adenophorae, Ramulus Cinnamomi. 3. The main durgs of each Peon-Zheng(辨證) are Rhizoma Cyperi, Radix Paeoniae Alba, Pericarpium Citri Reticulatae, Radix Aucklandiae, Radix Linderae in the symptoms of Ki-Chei(氣滯) Caused by Kan-Ki-Hoing-Yeog(肝氣橫逆) ; Radix Astrageli, Ramulus Cinnamomi, Radix Paeoniae Alba in the symptoms of Ki-Chei(氣滯) of Mog-Pul-So-To (木不疏土) caused by Kan-Ki-Her (肝氣虛) ; Radix Astragali, Ramulus Cinnamomi, Radix Paeoniae Alba, Radix Glycyrrhizae, Rhizoma Atractylodis Macrocephalae in the symptoms of Her-Han(虛寒);Radix Adenophorae, Radix Paeoniae Alba in the symptoms of Wei-Yeum-Her(胃陰虛) and Wul-Yeol(鬱熱) ; Rhizoma Cyperi, Rhizoma cotydalis, Resina Myrrhae in the symptoms of Yer-Heol(瘀血) ; Rhizoma Atractylodis, Pericarpium Citri Reticulatae, Cortex Magnoliae Officinalis in the symptoms od Tam-Kuel(痰厥). On the other hand, classifying and using the modification and utility method by the character of drug in order to coinside with Peon-Zheng (辨證) and pharmacologic effect, and finding out the therapeutic methods and prescriptions to protect the sideaction, it is considered that the better therapeutic effect will gain.

體育科 學習의 指導意欲과 能率의 極大化 方案에 關한 調査 分析 : 國民學校 敎師를 對象으로 Researching on the elementary School teachers

文圭鎭 釜山敎育大學 1981 부산교육대학 논문집 Vol.17 No.1

1. The purpose of this study The desiarable school education factors are considered as the qualities of teachers, teaching methods, techniques, student's needs and abilities, facilities, and curriculum etc. In order to improve physical education effects, I investigated about school environments, facilities, teaching aids, teachers' believes and qualities, teaching skills, physical education curricular, and their problems. 2. The research methods. I made 47 questionnaires, which were distributed to the 400 elementory school teachers (Men 103, Women 297 in Busan City) After correction from 385 teachers, I did analyze about A) the physical education facilities(9 questionnaires) B) the curriculum and its administration (23 questionnaires) C) the qualities of teachers and the other problems. 3. The Results 1) In refered to facilities, the criterion of the Ministry of Education must be reestablished from 49 classes to 85 classes 2) The physical education was put in practice three times each week, but one of them was bound to two classes. (group teaching) 3) The ball game was taught too frequently compare to other sports activities. 4) It was estimated that the present level of achievement was so high that the student couldn't reach there. 5) The swimming teaching was difficult without swimming pool, sea training, and special one-day swimming class. 6) The reason why physical education teaching was difficult were analyzed as follows; The teacher himself hasn't enough ability.(27.0%) The teachers' qualities(43.6%), the lack of facilities (29.1%), the interest and ability of students (15.3%), the difficulty of achievement level (11.9%) 7) They wanted the exclusive teaching system about all subjects (29.1%), but others wanted that this system must be used in Mucic, Fine Art, and Physical Education class (41.3%), 8) After executing the exculusive teaching system, Most of teachers (81.4%) showed positive response, but they reported that this had many difficulties. Concludly, I summarized as follows; First, the application of the exclusive teaching system, second, the extension and practical using of facilities, third, teachers' reeducating, fourth, the reinforcement of physical education in college, fifth, the modification of the present curricular in elememtary school physical education.

運動選手의 神經症的인 傾向에 關한 考察

文圭鎭 釜山敎育大學 1985 부산교육대학 논문집 Vol.21 No.1

The aim of this study is the comparative consideration about neurotic tendency, especially in obsessive-compulsive symptoms, between atheletes and general students. The subject of study are 704 general high school students and 471 athletes of both sexes who were participated in the 64th National Athletes Meeting of 27 items, held in 1984. The results obtained from this study were as follows: 1. Athletes are liable to behave obhave obsessive-compulsively in comparison with general students and general students are liable to think obsessive-compulsively in Comparison with athletes. 2. Athletes feel more anxiety than general students. 3. Athletes have more positive self-consciousness, which acknowledges themselves truly, than general students. 4. General male students feel more anticipation of their parents than male athletes, and female athletes feel more anticipation of their parents than general female students. 5. Athletes have the tendency to feel that it's painful to fall asleep, general female students are apt to suffer from headaches. 6. Male athletes have more ideas of reference than general male students and female general students have more ideas of reference than female athletes.

마이크로 프로세서를 이용한 CW송신 자동화 시스템

文建,金圭煥 군산대학교 1985 群山水産專門大學 硏究報告 Vol.19 No.3

In this paper, we described as to automatization on CW-transmission being mainly used in the maritime communication nowadays. The experimental results by using the edited programs and the developed interface hardware showed the excellent effectivity and accuracy. The CPU-6502 micro-processor was used in this system. It was proved that CW can be transmitted with good stability on the high speed more than 500CPM (characters per minute). We found that this system is very useful and effective and also save the the educational time of the students who are training the CW-morse code on keying and receiving skill.

구기종목형 학습과제 실기수업에서 교수행동 분석

문성철,이규하 인하대학교 스포츠과학연구소 2000 論文集 Vol.12 No.-

The purpose of this study was to investigate the teaching behavior in learning items of ballgame styles. The subjects of this study were 11 physical education teachers. For this study, time(one unit: five seconds) and 26 teaching behavior styles(atmosphere of class: class management, body exercise, audio-video learning activities, waiting activities, teacher's class behavior : class introduction, question activities, answer activities, listening activities, superintendence activities, negligence activities, class operation, body touch, encouragement activities, discipline activities, setting an example of teacher, setting an example of student, positive behavior feedback, negative behavior feedback, intimidation activities, positive technical feedback, negative technical feedback, correction feedback for technique, joining activities with students, interaction activities: personal interaction activities, group interaction activities, class interaction activities) were measured as frequencies. The inference and statistical verification of the research assumptions were made with the SPSS program(t-test, p<.05), and the following conclusions have been reached after a comparative study between the verification result and antecedent study results: In the sector of class atmosphere, the teaching behavior in learning items of ballgame styles, it was no good because the audio-video learning activities(71.9%) was more than the body exercise(20.3%). And the superintendence activities(43.7%) was more than the variety feedback, body touch, and question-answer. Thus, the presentation frequencies for cue about error peformance of learner lacked. It was good because the interaction activities of teacher has no difference among three elements(personal interaction activities, group interaction activities, class interaction activities).

중·고등학생들의 보건교육 요구도 조사연구

문기내,남철현,김귀희,위광복,박경옥,이미경,심규범,장영진 慶山大學校 保健福祉硏究所 2003 保健福祉硏究 Vol.8 No.-

This study was conducted to examine middleㆍhigh school 720 students in seven regions of middleㆍsmall city and town, Myon for 2 months from March 2 through April 30, 2002 in order to realize a side of school health education in middleㆍhigh school and health education need as well as health education specialist in school in the future. The results of this study can be summarized as follows. 1. Health condition is now 'normal' is 51.0%, 'good' is 45.0%, 'not good' is 4.1% and health condition of children is good as much as education level of mother is higher. 2. Experience to learn health education in school for one year recently is 'no' is 39.6%, 'don't know' is 32.6%, 'yes' is 27.8% and it represents health education in school doesn't work well and experience to learn health education is lower and lower in town and Myon. 3. Health education ways to work in school now are 'Movie, Video, Slide' is 40.7%, 'education as groups of nurse-teacher' is 38.6%, 'to distribute health education material and book' is 7.7%, 'education by setting an example' is 3.4%, 'the others' is 9.7%. 4. Time of appropriate health education for one time is 'about a hour' is 56.7%, 'about 30 minute' is 33.8%, 'about two hour' is 7.6%, it represents this situation is because of what students' time is lack and burden about a curriculum in an education administratin and school classed of a focused school score. 5. The average score of satisfaction of health education in school is 16.99±0.58, 'men' is 1.79±0.60, 'women' is 1.61±0.55 as the distinction of sex, satisfaction level of men is higher than women. 6. Learning route about health information is 'through mass media' is 59.9%. 'through family, friend' is 15.0% 'health education lecture' is 7.2%, 'printing media' is 6.1%, 'medical institution' is 5.6%, 'the others' is 5.1%, 'public health center' is 1.0%, 'through mass media' is the highest percent as each 59.1% and 60.6% in all of men and women. 7. The most efficient education way of health education is 'movie, video, slide' is 32.6%, 'health education specialist who works school' is 21.9%, 'school health education by nurse-teacher' is 16.0%, 'way through mass communication' is 11.6%. 8. The appropriate health education specialist in the future is 'health education specialist who has qualifications' is the highest as 64.5%, 'nurse-teacher' is 12.4%, 'medical personnel(doctor, a physician of oriental medicine etc.,)' is 11.0%, 'staff in public health center' is 7.2%, people in other regions(health and medical professor etc.,) is 7.0%, it represents school health education is not actual and is formal now in second hand. 9. The most necessary health education program is 'program of stress solution' is the highest as 24.9%, 'program of no smoking' is 22.7%, 'sexual education program' is 19.8%, 'school violence program' is 8.8%, 'isolate from their friends prevention program' is 8.0%, solution program of stress which gives student by school score was very necessary. Therefore, school health education is formal and inefficient because school education focuses on an entrance exam, so middleㆍhigh school students decrease concern and interest about health education. Furthermore, reliance is gotten down about nurse-teacher who takes charge of school health, a charged person of school health education wants more chargeable health education staff. And a solution program of stress that gives students by school score was very necessary. According to active concern and planned, systematic school health education is necessary to give right health knowledge, health maintenanceㆍpromotion and setting of appropriate health education specialist is very urgent.

SC를 利用한 逋續近似 A/D-D/A 變換器의 變換特性에 관한 硏究

文建,金圭煥 군산대학교 1989 群山水産專門大學 硏究報告 Vol.19 No.3

Recently, the demand of A/D-D/A Converter has been increased as an I/O of analog data communication systems. But, as the most of A/D-D/A converter was built in complex circuit with many resistors, capacitors, and switches, there are necessity to reduce the cost and the number of required elements. In this paper, the operation and conversion character of simple and economic A/D-D/A converter of successive approximation type designed by using switched capacitor were studied analytically and its conversion deviation was considered experimentally. The results were as follows: 1.A/D converter of more than 6 bits could be realized by varying the time chart without the increase of logic circuit. 2.The conversion of high accuracy with linearity could be realized since it was conformed that the experimental values of conversion deviation were less than 1/2 LSB. 3.A part of the A/D converter could be used as D/A converter without changing the elements of circuit.