• Journal of the Korean Data and Information Science Society
• /
• v.25 no.5
• /
• pp.1117-1125
• /
• 2014

In a longitudinal study, subjects can experience same type of events repeatedly. Also, there may exist intermittent dropouts resulting in repeated observation gaps during which no recurrent events are observed. Furthermore, when such observation gaps have incomplete forms caused by the unknown termination times of observation gaps, ordinary approaches result in biased estimates. In this study, we investigate the effect of ignoring observation gaps and propose methods to overcome this problem. For estimating the distribution of unknown termination times, an interval-censored mechanism is applied and two cases are considered. Simulation studies are carried out to evaluate the performance of the proposed method. Conviction data of young drivers with several suspensions are analyzed to illustrate the suggested approach.

• Publications of The Korean Astronomical Society
• /
• v.19 no.1
• /
• pp.55-63
• /
• 2004

Observation environment of the Bohyunsan Optical Astronomy Observatory(BOAO) has been examined using various statistical data including real observation times versus allocated times and seeing statistics. The data have been collected from the observation logs of the 1.8m telescope in the period 1998 - 2004. New criteria have been set up to calculate a more realistic observation efficiency of the observatory. The new statistical analysis based on the new criteria gives the overall observation efficiency of BOAO as $38.6\%$, that is equivalent to 115.8 observable nights out of 300 allocatable nights. The seeing statistics shows that the mean seeing measured at the focal images is 2".3. The present study of the observation environment of BOAO suggests that differential photometry and spectroscopy should be preferred modes of observation to maximize the productivity of BOAO.

• Korean Institute of Interior Design Journal
• /
• v.23 no.2
• /
• pp.90-98
• /
• 2014

This study has analyzed the meaning of observation time in the course of acquiring the information of subjects who observed the space of hall in subway stations to figure out the process of spatial information excluded and the features of intensive searching. The followings are the results from the analysis of searching process with the interpretation of the process for information acquirement through the interpretation of observation area and time. First, based on the general definition of observation time, the reason for analyzing the features of acquiring spatial information according to the subjects' observation time has been established. The feature of decreased analysis data reflected that of observation time in the process of perceiving and recognizing spatial information, which showed that the observation was focused on the enter of the space during the time spent in the process of observing the space and the spent time with considerable exclusion of bottom end (in particular, right bottom end). Second, while the subjects were observing the space of hall in subway stations, they focused on the top of the left center and the signs on the right exit the most, which was followed by the focus on the both side horizontally and the clock on the top. Third, the analysis of consecutive observation frequency enabled the comparison of the changes to the observation concentration by area. The difference of time by area produced the data with which the change to the contents of spatial searching in the process of searching space could be known. Fourth, as the observation frequency in the area of I changed [three times -> six times -> 9 times], the observation time included in the area increased, which showed the process for the change from perception to recognition of information with the concentration of attention through visual information. It makes it possible to understand that more time was spent on the information to be acquired with the exclusion of the unnecessary information around.

• Korean Institute of Interior Design Journal
• /
• v.21 no.4
• /
• pp.87-95
• /
• 2012

This study is for the analysis to which element of space the users observing the lobby at a public space pay more attention for their visual perception. It is focused on the typology process of observation characters. The subjects, in the observation process, came to be interested in the circumstantial clues for space perception and the detailed characters drawing their interest. I could analyze the observation characters of the subjects observing the space by the comprehension and typology of their observation characters. First, from the viewpoint of successive 9 times of observations, each subject observed for 0.32 second to get the visual perception in the applied space, but spent another 0.39 second for the exploration of another observation object or the space roaming. The observation character of the subjects at the lobby of the public space selected for this experiment was that they spent more time on space exploration than on concentration on a point in the space. Second, I analyzed the typology process through the time range. Since the subjects' frequency varied depending on the way to set up the time range, the necessity was proposed that the time range for the analysis of observation characters should be set up more objectively. Third, in case of analyzing the observation characters by 10-second-unit time range, the concentration in the beginning and the middle was 25%, and that in the beginning and the final 41.7%, which showed that 75% of the subjects concentrated in the beginning of the observation time when the concentration in the beginning is added to it. Fourth, the type 3 categorized as "concentration in the beginning and the middle" is the group 47.1 percent of the subjects belong to, and each subject concentrated 1.1 times in the beginning and 2.1 times in the final, which showed that the concentration in the final was 1.75 times as high as that in the beginning.

• Journal of Ocean Engineering and Technology
• /
• v.33 no.6
• /
• pp.607-614
• /
• 2019

It has been an issue among researchers that the tsunamis that occurred on the west coast of Japan in 1983 and 1993 damaged the coastal cities on the east coast of Korea. In order to predict and reduce the damage to the Korean Peninsula effectively, it is necessary to install offshore tsunami observation instruments as part of the system for the early detection of tsunamis. The purpose of this study is to recommend the optimal deployment of tsunami observation instruments in terms of the higher probability of tsunami detection with the minimum equipment and the maximum evacuation and warning time according to the current situation in Korea. In order to propose the optimal location of the tsunami observation equipment, this study will analyze the tsunami propagation phenomena on the east sea by considering the potential tsunami scenario on the west coast of Japan through numerical modeling using the COrnell Multi-grid COupled Tsunami (COMCOT) model. Based on the results of the numerical model, this study suggested the optimal deployment of Korea's offshore tsunami observation instruments on the northeast side of Ulleung Island.

• Journal of the Korean Society of Earth Science Education
• /
• v.4 no.1
• /
• pp.20-31
• /
• 2011

The purpose of this study is to examine the effect of PBL-based astronomical observation on the science process skills and scientific attitudes in elementary science-gifted students. To verify research problems, the subjects of this study were forth-grade students selected from one classes of an elementary science-gifted class in Busan National University of education : the research group is composed of twenty students who were participated in PBL-based astronomical observation program. During four weeks, the PBL-based astronomical observation program instruction was executed in the reasearch group. Post-test showed following results: First, the research group showed a significant improvement in the science process skill. We look into detailly this, the research group showed a significant improvement in the basis science skill. The sub-factor 'expectation' of the science process skill effects a significant improvement. Second, the research group showed a significant improvement in the scientific attitudes. In conclusion, PBL-based astronomical observation program was more effective on science process skill and scientific attitudes. However, since the study has a limit on an object of the study and the applied program, the additional studies need to be conducted with an extended comparative group and program.

• Journal of Science Education
• /
• v.35 no.2
• /
• pp.127-137
• /
• 2011

The purpose of this study is to develop the analysis frame of reporting observation results by high school students in biology experiments using microscopes and analyze their error types. For this study, five experiments were carried out by 12 high school students in B metropolitan city. Before these experiments, developed the analysis frame of reporting observation results. Tests for checking prior knowledge of students were done and results of each experiment were taken picture of. Using the developed framework, the real results and reported results submitted by students were analyzed. The result of this study shows how students report their observation results and they tend to have difficulty in doing observation activity itself. The ratio of factual reports is low because observation ways and recording ways have not been taught properly. Observation training is needed for observing real results objectively. The improvement in experiment environment is necessary for right observation, not observation for checking based on only results. In addition, the education of ethics in science research focusing on the integrity should be performed. The analysis data of reporting observation result by students can be used as basic data for teachers to plan observation strategies and to have right observation views and ways.

• 대한공업교육학회지
• /
• v.43 no.1
• /
• pp.114-133
• /
• 2018

The purpose of this study was to develop an observation and analysis instrument for invention educational activities for monitoring and improving the educational activities of inventions. For this study, a draft of observation and analysis instrument was developed through review of literatures. It was validated through opinion gathering from 10 experts of invention educational expert opinion convergence based on the content validity index (CVI) of Fehring (1987). The results of the study were as follows: First, the frame of observation and analysis of the invention education activity consists of three dimensions of observation object, observation phase and observation contents. Second, the instrument for observing and analyzing invention education activities are composed of analysts, observation subjects, observation class contents, teacher observation and analysis, student observation and analysis, educational environment and task observation and analysis. Third, the developed tools were designed to describe opinions and general opinions about individual observation factors besides the 5 - point Likert scale. Through this, it is expected that educational activities will be improved in addition to qualitative evaluation through monitoring of future invention education activities.

• Journal of Convergence for Information Technology
• /
• v.10 no.8
• /
• pp.229-238
• /
• 2020

This study was conducted to investigate the effect of gradually decreasing action observation training on the upper extremity function and Activities of daily living in chronic stroke patients. For patients with chronic stroke, the groups were divided into experimental group undergoing gradually decreasing action observation training(n=4), control group receiving existing action observation training(n=3) and the study was conducted 6 times a week, 30 minutes per session for a total of 2 weeks. The results of the comparison between the groups before and after intervention and the comparison between the two groups did not show statistically significant differences in BBT, FMA, K-MBI, and MAL, but the experimental group showed a greater difference in terms of average score than the control group. As a result, it was confirmed that gradually decreasing action observation training can have a more positive effect than the existing action observation training.

• Atmosphere
• /
• v.30 no.2
• /
• pp.169-181
• /
• 2020

We conducted a study on the impact of observation station density; this was done in order to enable the accurate estimation of spatial meteorological variables. The purpose of this study is to help operate an efficient observation network by examining distributions of temperature, relative humidity, and wind speed in a test area of a three-dimensional meteorological observation project in the Yeongdong region in 2019. For our analysis, we grouped the observation stations as follows: 41 stations (for Step 4), 34 stations (for Step 3), 17 stations (for Step 2), and 10 stations (for Step 1). Grid values were interpolated using the kriging method. We compared the spatial accuracy of the estimated meteorological grid by using station density. The effect of increased observation network density varied and was dependent on meteorological variables and weather conditions. The temperature is sufficient for the current weather observation network (featuring an average distance about 9.30 km between stations), and the relative humidity is sufficient when the average distance between stations is about 5.04 km. However, it is recommended that all observation networks, with an average distance of approximately 4.59 km between stations, be utilized for monitoring wind speed. In addition, this also enables the operation of an effective observation network through the classification of outliers.