• Title/Summary/Keyword: Field Observational Study

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Angles-Only Initial Orbit Determination of Low Earth Orbit (LEO) Satellites Using Real Observational Data

  • Hwang, Hyewon;Park, Sang-Young;Lee, Eunji
    • Journal of Astronomy and Space Sciences
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    • v.36 no.3
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    • pp.187-197
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    • 2019
  • The Optical Wide-field patroL-Network (OWL-Net) is a Korean optical space surveillance system used to track and monitor objects in space. In this study, the characteristics of four Initial Orbit Determination (IOD) methods were analyzed using artificial observational data from Low Earth Orbit satellites, and an appropriate IOD method was selected for use as the initial value of Precise Orbit Determination using OWL-Net data. Various simulations were performed according to the properties of observational data, such as noise level and observational time interval, to confirm the characteristics of the IOD methods. The IOD results produced via the OWL-Net observational data were then compared with Two Line Elements data to verify the accuracy of each IOD method. This paper, thus, suggests the best method for IOD, according to the properties of angles-only data, for use even when the ephemeris of a satellite is unknown.

Seismic vulnerability assessment of buildings based on damage data after a near field earthquake (7 September 1999 Athens - Greece)

  • Eleftheriadou, Anastasia K.;Karabinis, Athanasios I.
    • Earthquakes and Structures
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    • v.3 no.2
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    • pp.117-140
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    • 2012
  • The proposed research includes a comprehensive study on the seismic vulnerability assessment of typical building types, representative of the structural materials, the seismic codes and the construction techniques of Southern Europe. A damage database is created after the elaboration of the results of the observational data obtained from post-earthquake surveys carried out in the area struck by the September 7, 1999 Athens earthquake, a near field seismic event in an extended urban region. The observational database comprises 180.945 buildings which developed damage of varying degree, type and extent. The dataset is elaborated in order to gather useful information about the structural parameters influence on the seismic vulnerability and their correlation to the type and degree of building damages in near field earthquakes. The damage calibration of the observational data was based on label - damage provided by Earthquake Planning and Protection Organization (EPPO) in Greece and referred to the qualitative characterization for the recording of damage in post-earthquake surveys. Important conclusions are drawn on the parameters that influence the seismic response based on the wide homogeneous database which adds to the reliability of the collected information and reduces the scatter on the produced results.

Ground Behavior Analysis of Excavation near High Rising Building and Field Observation Control (도심지 굴착에서 지반의 거동예측과 계측관리)

  • 기홍석;박근수;오재화;이문수
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1998.10a
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    • pp.401-406
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    • 1998
  • This study aimed at the technique for the construction control in braced excavation works. Selecting a case of Kwangju subway works, field observational values were compared with prediction using Plaxis's. Maximum observational values relevant to both horizontal and vertical proved satisfactory in that they were within the criteria. Numerical results by used Plaxis were overestimated greater than observational values, which meant the prediction were safe tendency. .It must be emphasized that displacement measurement for neighboring important structures should be carried out in order to take countermeasure charge for construction methods, in case that the risk or failure was previewed.

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A Sensitivity Study of WRF Model Simulations to Nudging Methods for A Yeongdong Heavy Snowfall Event (영동 대설 사례를 대상으로 한 WRF Simulation의 Nudging 방법에 따른 민감도 연구)

  • Choi, Ji Won;Lee, Jae Gyoo
    • Atmosphere
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    • v.25 no.1
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    • pp.99-115
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    • 2015
  • To investigate the influences of the observational nudging and the analysis nudging on the WRF simulation for the heavy snowfall event in Yeongdong area on 26 February 2012, the sensitivity experiments in relation to nudging effects were conducted. We initially set the magnitude of nudging coefficient of $6.0{\times}10^{-4}s^{-1}$ to apply to the analysis nudging experiments and observational experiments. To select the optimized options for the observational nudging, the radius influence experiment was carried out with radii ranging from 10 to 25 km at 5 km intervals. Among the observational nudging experiments, the experiment, which was conducted with the option of the radius influence of 15 km and that of the nudging coefficient of $6.0{\times}10^{-4}s^{-1}$ (ONG exp.), showed a best result. As giving the nudging effect only directly on D1 and D2 brought about a better result for the analysis nudging, we set the analysis nudging experiment as above (ANG exp.). We compared and analyzed the results from the control experiment, ONG experiment, and ANG experiment to reveal nudging effects. It was found that the control experiment brought about a result that it overestimated its precipitation in comparison with the observation and failed to properly simulate the time zone of rainfall concentration. When either of the two nudging (observational and analysis nudging) was applied to the data assimilation, it brought about a better result than the control experiment. Especially the observational nudging led to a meaningful result for the wind field, while the analysis nudging had the best result for the precipitation distribution among the experiments.

Development and Application of Virtual Geological Field Trip Program using 3D Panorama Virtual Reality Technique (3D 파노라마 가상 현실 기술을 이용한 지질 답사 학습 자료의 개발과 적용)

  • Kim, Hee-Soo
    • Journal of the Korean earth science society
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    • v.35 no.3
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    • pp.180-191
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    • 2014
  • In this study, a geological field trip learning program using 3 Dpanorama virtual reality (PVR) techniques is developed to learn about the Chaeseokgang area located in a national park near Byeonsan-bando, Jeonbuk, Korea. The developed $360^{\circ}{\times}180^{\circ}$ PVR program can show every face of observational points and interact as zoom-in, zoom-out and image rotation. For the educational effects of the materials, it is provided with a compass, a protractor for measuring the dip of strata and observation of specimen of observational points. It also assists students to learn by providing enlarged images, pop-up windows, and expert explanation main observational points. The program is applied to the class of 35 gifted students in middle school to investigate the effectiveness of the program. The results showed that positive responses of the students were 85% or more. It is suggests that this program be used as indirect situated learning material and a solution to geological field trip problems like cost, safety, distance, and so on geological learning of middle school science.

Korean Domestic Trends of Clinical Research and Direction of Intervention for Fibromyalgia (섬유근통에 대한 국내 임상 연구 동향 및 중재 방향)

  • Lee, Jung-Han;Geum, Ji-Hye;Woo, Hyeon-Jun;Lee, Chang-Hoon;Chung, Chong-Hyuk;Lee, Myeung-Su
    • The Journal of Churna Manual Medicine for Spine and Nerves
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    • v.15 no.2
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    • pp.43-54
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    • 2020
  • Objectives The purpose of this review was to analyze the trend of clinical research related to fibromyalgia and to suggest the direction of intervention Methods We reviewed the clinical research by searching seven Korean web databases and classified the studies by the year of publication, academic field, and study design. Results A total of 75 clinical studies were selected. Except for 2002, more than one study was annually published; however, the number was below 10. In the academic field, there were 34 in the medical field, 21 in the Korean medicine field, and 15 in the nursing science field. By study design, there were 62 observational studies, mostly case reports and case-control studies. There were 13 experimental studies, including non-random control studies and one group pre and post-test design studies. Conclusions Fibromyalgia-related clinical research requires a greater number of studies, and a study design with a high level of evidence should be conducted along with various observational and intervention studies. Additionally, multidisciplinary and integrated intervention plans and research are needed.

Development of Gap Acceptance Models for Permitted Left Turn Intersections (비보호좌회전에서의 간격수락 행태모형 개발)

  • Lee, Chung Won;Lee, Dong Min;Hwang, Soon Cheon
    • International Journal of Highway Engineering
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    • v.18 no.5
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    • pp.95-103
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    • 2016
  • PURPOSES : Permitted left turn is a turning maneuver in which a vehicle turns left using a gap between oncoming vehicles, called gap acceptance, and it enables for more efficient traffic operation at intersections. In Korea, the permitted left turn has not been a common maneuver at signalized or un-signalized intersections. However, many experts and the Police Agency tried to apply this effective turning maneuver at intersections in Korea since 2010. Though the investigation of gap acceptance is significantly important in understanding a driver's behavior at intersections, there have not been many studies about this topic, specifically a study to develop probability models of gap acceptance behavior. METHODS : In this study, the probability model of gap acceptance behavior for a permitted left turn was developed based on observational field studies. To develop the model, seven variables were analyzed including gap, waiting time, traffic volume, conflict-flow vehicle type, left-turning vehicle type, the number of lane, and time. RESULTS : In the final model, gap and left-turning vehicle type were found to be significant influencing factors. CONCLUSIONS : Through this model development, it was concluded that as the gap size increased, the probability of gap acceptance was higher. Moreover, when a left-turning vehicle was a passenger car, the probability of gap acceptance was higher than compared to large size buses or freight cars.

An Analysis of Observations and Hypotheses of Elementary School Students on Sedimentary Rocks and Geological Structures in Field Courses (야외 지질 학습장의 퇴적암과 지질 구조에 관한 초등학생들의 관찰 및 가설 분석)

  • Seo, Dong-Wook
    • Journal of the Korean earth science society
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    • v.25 no.7
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    • pp.586-594
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    • 2004
  • This study is the qualitative study in order to discover a direction of field courses by analyzing what elementary school students observe or hypothesis in field courses. The purpose of it is to find any relevancy between the observations and hypotheses generated. The result of the study were as follows; First, most participants have observed mostly based on their vision due to the characteristic of field courses, and the observations of sedimentary layers were mainly generated on the rocks while most hypotheses were on geological structures. Secondly, according to observational descriptions the frequency of the comparative observation was high as well as the cases when two different types of observations were joined together. The last conclusion from this investigation is, according to the standard of observational types, the hypotheses combined with the interpretive observation and comparative observation had the greatest percentage. This shows that many participants tried to rationalize their thoughts by interpreting geological structures and comparing them with other people's cases as well. Scientific explanatory hypotheses were mainly found according to the standard of hypothetical types, which can be constructed that those participants tried to explain and apply established knowledge and preconception.

The Visual Art Teachers' Perceptions on the Observational Evaluation System for the Artistic Giftedness in Elementary and Middle School (미술영재 판별을 위한 관찰 평가 도구에 관한 초·중학교 미술교사들의 인식 조사 연구)

  • Kang, Byoungjik;Maeng, HeeJu
    • Journal of Gifted/Talented Education
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    • v.26 no.1
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    • pp.123-140
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    • 2016
  • This study searched the perception of observational evaluation system in visual art which elementary and middle school teachers have in mind. As results, observational evaluation system in visual art is widely accepted as important and efficient to diagnose the artistic giftedness. At the same time, subjectiveness of the system might be advantageous for student for whom teacher get favor and in-service program related to observational evaluation system is insufficient comparing to the demand from field. In spite of this, the scale for behavioral characteristics of the gifted in visual art and the test for artistic task performance are recognized as the most important and needed tools for evaluating artistic giftedness. Following the results, in order to raise up the validity and reliability of evaluation in visual art, the scales for behavioral characteristics of the gifted in visual art and the test for artistic task performance should be developed first and foremost.

Effects of Sweet Bee Venom on the Central Nervous System in Rats -using the Functional Observational Battery- (Sweet BV 시술이 Rat의 중추신경계에 미치는 영향 - 기능관찰 종합평가를 이용하여-)

  • An, Joong-Chul;Kwon, Ki-Rok
    • Journal of Pharmacopuncture
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    • v.14 no.3
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    • pp.19-45
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    • 2011
  • Objectives: This study was performed to analyse the effects of Sweet Bee Venom(Sweet BV-pure melittin, the major component of honey bee venom) on the central nervous system in rats. Methods: All experiments were conducted at Biotoxtech Company, a non-clinical studies authorized institution, under the regulations of Good Laboratory Practice (GLP). Male rats of 5 weeks old were chosen for this study and after confirming condition of rats was stable, Sweet BV was administered in thigh muscle of rats. And checked the effects of Sweet BV on the central nervous system using the functional observational battery (FOB), which is a neuro-toxicity screening assay composed of 30 descriptive, scalar, binary, and continuous endpoints. And home cage observations, home cage removal and handling, open field activity, sensorimotor reflex test/physiological measurements were conducted. Results: 1. In the home cage observation, there was not observed any abnormal signs in rats. 2. In the observation of open field activity, the reduction of number of unit areas crossed and rearing count was observed caused by Sweet BV treatment. 3. In the observation of handling reactivity, there was not observed any abnormal signs in rats. 4. In the observation of sensorimotor reflex tests/physiological measurements, there was not observed any neurotoxic signs in rats. 5. In the measurement of rectal temperature, treatment of Sweet BV did not showed great influences in the body temperature of rats. Conclusions: Above findings suggest that Sweet BV is relatively safe treatment in the central nervous system. But in the using of over dose, Sweet BV may the cause of local pain and disturbance of movement. Further studies on the subject should be conducted to yield more concrete evidences.