• Journal of Astronomy and Space Sciences
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• v.25 no.1
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• pp.43-52
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• 2008

As the next generation of global satellite navigation system, the Galileo project is about to witness an initial orbit validation stage as the successful test of navigation message transmission from Giove-A in 2007. The Space Geodesy division ana the Radio Astronomy division of the Korea Astronomy & Space Science Institute had collaborated on the field survey for the Galileo Sensor Station (GSS) RF environment of the proposed site near Jeju Tamla University from August 3rd to August 5th, 2006. The power spectrums were measured in full-band $(800{\sim}2000MHz)$ and in-band (E5, E6 and L1 band) in frequency domain for 24 hours respectively. Finally, we performed a time domain analysis to characterize strong in-band interference source based on the result of the previous step.

• Korean Journal of Construction Engineering and Management
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• v.18 no.6
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• pp.57-64
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• 2017

Recently, the disaster situation has been diversified and compounded worldwide as well as in Korea. And the damage scale of each disasters have increased, and following economic loss is also increasing immensely. In Korea, especially the out break frequency of large-scale disasters has increased. Disasters caused by earthquakes are also very likely to occur. When a major accident such as Mauna resort collapse accident, Ferry sewol sinking accident occurred, systematic emergency medical care at the site at the time of disaster occurred in order to operate an emergency medical facility corresponding to the site, which is not systematic. The need for this service is urgent. If highly reliable emergency medical system function at appropriate times in the disaster site, secondary damage can be reduced and the whole situation would be back to normal shortly. Therefore, it is necessary to provide an emergency medical system capable of quickly and safely responding to disaster sites in relation to various damage scale. For the purpose, thorough analysis on mobile medical units of inside and outside the country was accomplished. As a result, Mobile Medical Unit of outside the country are trailer type, tent type, container type etc. At home, these types have been studied and will be proposed early next year as a temporary solution. Here we introduce suitable types for our country.

• Journal of the Korean Society of School Health
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• v.11 no.1
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• pp.63-74
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• 1998

The purposes of this study are to show in interpersonal relations what factors male students are stressed from, how they experience stress, how they cope With it in each situation, and what this results in It attempt to gam basic materials to promote male student health and positive coping methods, The subject of this study was 15 male students of C University located in Seoul and Kyeonggui-Do They were composed of 5 sophomores, 5 Juniors and 5 seniors The period for collecting materials was October 1997 to January 1998, and the interview time ranged from 50 minutes to two hours The interview frequency was one to three times as occasion demanded, The materials were analyzed by the methods and theory suggested by Strauss & Corbin (1990) The results were 130 categories grouped into 33 divisions by similarity Finally, they were united into 9 higher categories In interpersonal relations the core category of male student stress is "affliction", and it follows the course of generation-coping-resolution The types showed in the course of material analysis are as follows, (1) When the subject student is on good terms with the other and the stress is repeated- "affliction" is strong and continuous-and his ability sense is strong, he copes with "affliction" With his own will and solves It affirmatively, (2) When the subject student is on good terms with the other and the stress is repeated-so "affliction" is strong and continuous-and his ability sense is weak, he copes with "affliction" with an emotional bias and solves it negatively (3) When the subject student is on good terms with the other and the stress is temporary-"affliction" is strong and temporary-and his ability sense is strong, he copes with "affliction" with his own will and solves it affirmatively (4) When the subject student becomes estranged from the other and the stress is temporary-"affliction" is weak and temporary-and his ability sense is weak, he copes with "affliction" with an emotional bias and solves it negatively, (5) When the subject student becomes estranged from the other and the stress is repeated-"affliction" is strong-and continuous and his ability sense is strong, he copes with "affliction" with his own will and solves it affirmatively (6) When the subject student becomes estranged from the other and the stress is repeated-"affliction" is strong and continuous-and his ability sense is weak, he copes with "affliction" with an emotional bias and solves it negatively. According to the above results, the conditions of cause and effect for male students to generate "affliction" should be understood in order to help cope with stress caused by interpersonal relations A program for education and counseling should be developed for male students to strengthen their 'ability sense' in choosing coping strategies In addition, the individual estimation for ability sense should be performed when education and counseling them.

• Journal of Korea Water Resources Association
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• v.51 no.8
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• pp.703-711
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• 2018

Water distribution system (WDS) pipe bursts are caused from excessive pressure, pipe aging, and ground shift from temperature change and earthquake. Prompt detection of and response to the failure event help prevent large-scale service interruption and catastrophic sinkhole generation. To that end, this study proposes a improved Western Electric Company (WECO) method to improve the detection effectiveness and efficiency of the original WECO method. The original WECO method is an univariate Statistical Process Control (SPC) technique used for identifying any non-random patterns in system output data. The improved WECO method multiples a threshold modifier (w) to each threshold of WECO sub-rules in order to control the sensitivity of anomaly detection in a water distribution network of interest. The Austin network was used to demonstrated the proposed method in which normal random and abnormal pipe flow data were generated. The best w value was identified from a sensitivity analysis, and the impact of measurement frequency (dt = 5, 10, 15 min etc.) was also investigated. The proposed method was compared to the original WECO method with respect to detection probability, false alarm rate, and averaged detection time. Finally, this study provides a set of guidelines on the use of the WECO method for real-life WDS pipe burst detection.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.5
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• pp.88-96
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• 2014

In modern electronic warfare systems, the necessity of a more accurate estimation method based on non-AOA (arrival of angle) measurement, such as TDOA and FDOA, have been increased. The previous researches using single TDOA have been carried out in terms of not only the development of emitter location algorithms but also the enhancement of measurement accuracy. Recently, however, the combined TDOA/FDOA method is of considerable interest because it is able to estimate the velocity vector of a moving emitter and acquire a pair of TDOA and FDOA measurements from a single sensor pair. In this circumstance, it is needed to derive the required FDOA measurement accuracy in order that the TDOA/FDOA combined localization system outperforms the previous single TDOA localization systems. Therefore, we analyze the contribution of FDOA measurement accuracy to emitter location, then propose the criterion based on CRLB (Cramer-Rao lower bound). Simulations are included to examine the validity of the proposed criterion by using the Gauss-Newton algorithm.

• Publications of The Korean Astronomical Society
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• v.30 no.3
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• pp.821-832
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• 2015

As a part of the short-period variability survey (SPVS) at Bohyunsan Optical Astronomy Observatory, we obtained time-series BV CCD images in the region of the open cluster NGC 1039 (M34). The observations were performed for 22 nights from July 29, 2008 to September 26, 2010. We also made LOAO observations for 10 days from September 18, 2009 to October 30, 2010 to confirm the small variabilties of ${\delta}$ Scuti-type variable stars. In this paper we presented the observational properties of 28 variable stars found in the region. They are seven ${\delta}$ Scuti-type variable stars, two ${\gamma}$ Doradus-type variable stars, four-teen eclipsing binary stars and five semi-long periodic or slow irregular variables, respectively. Only three variables were listed in the GCVS and the rest are newly discovered ones. We have performed multiple-frequency analysis to determine pulsation frequencies of the ${\delta}$ Scuti-type and ${\gamma}$ Doradus-type variable stars, using the discrete Fourier transform and linear least-square fitting methods. We also have derived the periods and amplitudes of 12 eclipsing binaries from the phase fitting method, and presented the light curves of all variable stars.

• Journal of The Korean Association of Information Education
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• v.10 no.1
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• pp.47-57
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• 2006

As teenagers' Internet use increases and Internet takes an important part in their everyday lives, many people become concerned with Internet addiction. In this study, I attempt to analyze the current status of teenagers' Internet addiction using an evaluation tool developed for students, and to compare elementary students' Internet addiction level with secondary students. Also I analyze factors affecting Internet addiction. For the analysis, 18 variables are selected from the areas such as demographic background, the experience of Internet use, family-related traits and social activities. A survey was conducted to 1,155 elementary students and 1,822 secondary students selected from nationwide schools. The main finding of this study is that among the elementary students 5.0% of the sample students are in the stage of serious addiction, and 19.7% in the stage of early addiction. In addition, the level of elementary students' Internet addiction is significantly higher than the level of secondary students. Also, the degree of elementary students' Internet addiction is significantly affected by some factors such as gender, surfing time, surfing purpose, satisfaction with parental relationship, parents' interference in Internet use, conversation frequency among family members, and satisfaction with school life.

• Journal of the Korea Convergence Society
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• v.9 no.1
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• pp.387-392
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• 2018

The aim of this study was to determine the statistical significance of heart rate variability(HRV) between sleep stages, Apnea-hypopnea index(AHI) and age in patients with obstructive sleep apnea(OSA). This study evaluated the main parameters of HRV over time domain and frequency domain in 40 patients with sleep apnea. The non-REM(sleep stage) was statistically validated by comparing the AHI degree of the three groups(mild, moderate, severe) of sleep apnea patients. The NN50(p=0.043), pNN50(p=0.044), VLF peak(p=0.022), LF/HF(p=0.028) were statistically significant in the R-R interval of patients with sleep apnea from the control group (p<0.05). The LF / HF (p = 0.045) and HF power (p = 0.0395) parameters between the non-RAM sleep (sleep 2 phase) and REM sleep in patients with sleep apnea were statistically significant in the control group(p<0.05). We may be able to provide a basis for understanding the correlation among AHI, sleep stage and age and heart rate variability in patients with obstructive sleep apnea.

• Spatial Information Research
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• v.20 no.1
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• pp.9-18
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• 2012

South Korea has many landslides caused by heavy rains during summer time recently and the landslides continue to cause damages in many places. These landslides occur repeatedly each year, and the frequency of landslides is expected to increase in the coming future due to dramatic global climate change. In Korea, 81.5% of the population is living in urban areas and about 1,055 million people are living in Seoul. In 2011, the landslide that occurred in Seocho-dong killed 18 people and about 9% of Seoul's area is under the same land conditions as Seocho-dong. Even the size of landslide occurred in a city is small, but it is more likely to cause a big disaster because of a greater population density in the city. So far, the effort has been made to identify landslide vulnerability and causes, but now, the new dem and arises for the prediction study about the areal extent of disaster area in case of landslides. In this study, the diffusion model of the landslide disaster area was established based on Cellular Automata(CA) to analyze the physical diffusion forms of landslide. This study compared the accuracy with the Seocho-dong landslide case, which occurred in July 2011, applying the SCIDDICA model and the CAESAR model. The SCIDDICA model involves the following variables, such as the movement rules and the topographical obstacles, and the CAESAR model is also applied to this process to simulate the changes of deposition and erosion.

• The Korean Journal of Community Living Science
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• v.18 no.2
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• pp.323-334
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• 2007

This study was made to analyze the condition and the needs of nutrition education considering the different stage of nutrition education recognized by the dietitian in industrial area. 165 female dietitian were surveyed by questionnaire and they were divided into 4 groups according to the different recognition stages of nutrition education: Pre-contemplation(PC) 4.8%, Contemplation(CO) 46.7%, Preparation(PR) 22.4%, Action & Maintenance phase(AM) 26.1%. For statistical analysis, SAS(Ver.8.1. for Window) was used to find out the distribution related with nutrition education and to calculate the scores of mean and standard deviation. General characteristics of the subjects are about 20 years old(71.5%), single(69.7%), careers over 5 years(40%) and university graduates(73.9%). The number of meals(p<0.05) and the employment status(p<0.05) were significantly different according to the recognized stage of nutrition education. The practice of nutrition education was different depending on the dietitian in the industry. Many of the factory dietitian were in pre-contemplation stage(87.5%), however, those in the office and service area were more in Action & Maintenance stage(27.9%). In the industrial area, just 26.1% of dietitian operated the nutrition education and most did not due to the work overload and insufficient support of staff(73.3%). The frequency for the most effective nutrition education was once a month(61.2%). The contents for desirable nutrition education were in the order of 'eating habits'(36.1%), 'relation with the daily life'(23.5%), 'food hygiene' (21.7%), 'nutrition knowledge'(9.7%), and 'disease prevention'(9%). In operating nutrition education, dietitian had concerns about 'insufficient support of staff', 'shortage of teaching materials' and 'lack of time'. And, the dietitian who were with lower recognition stage of nutrition education(P<0.05) concerned more about the insufficient educational contents. In conclusion, dietitian in the industry highly recognized the need of nutrition education, but it was so difficult to practice. For more programs and various materials should be developed, and the staff's perception, the view of dietitian and the meal service should be changed, too. For the health improvement of industrial workers, it would be necessary to proclaim the importance of nutrition education nationwide.