• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.12
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• pp.865-873
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• 2019

To improve the survivability of a missile, it needs to be lowered that the detection possibility by radars on the ground. The radar exposure of the target is given as a function of relative distance from the radar to the target and RCS (Radar Cross Section). The RCS of the missile is determined by the incidence angle of the target to electromagnetic radiation emitted from the radar. Under the assumption that the missile equips appropriate attitude control system, the attitude of the missile to minimize radar exposure at a high altitude is investigated in this paper. Two different types of performance cost are considered: the total sum of RCS and the total sum of SNR during the flight. Optimal solutions against multiple ground radars are found by using a SQP (Sequential Quadratic Programming)-based optimization technique.

• Korean Journal of Community Nutrition
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• v.9 no.4
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• pp.453-463
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• 2004

In order to investigate food purchase frequency of elementary school children and its related ecological factors, 431 4th, 5th and 6th grade elementary school children and their mothers, living in Seoul and Daejon, small city and rural area of Chungnam Province, were participated in this study. The subjects and their parents were surveyed by a self-recording questionnaire about food purchase frequency and some ecological factors. Average height and weight of the subjects by gender and grade were similar to or a little bit more than the 1998 Korean Growth Standard. According to relative body weight, 30.6% and 10.8% of the subjects belonged to under-weight and obesity categories, respectively. Of the subjects, 46.9% used PC telecommunication or internet, 53.8% of them used it for less than an hour per day, and 46.4% watched TV for 2 to 4 hours a day. About 42% of the subjects spent 500 Won or less daily to buy snacks. A half of the subjects took snacks once a day because of hunger. Mothers' nutrition knowledge score was averagely 8.16 out of 13 full score and the average attitude score was 43.22 out of 50 full score. Foods purchased more than once a week were milk and yoghurt, cookies, ice-cream, ramyun, and gum in order. Family income, parents' education level, mothers' nutrition knowledge and food attitude score, students' snacking frequency and TV watching time showed significant correlations with purchase frequencies of some individual food items. In conclusion, the elementary school children considered taste most important rather than nutrition in buying snacks and most frequently bought carbohydrate foods and concentrated sugars except milk. Ecological factors such as mothers' nutritional knowledge and food attitude, TV watching time and snacking frequency had influenced the children's food purchase frequency. Accordingly, it is necessary to educate both children and their mothers about good food purchase and the importance of snacking.

• Journal of Korean Public Health Nursing
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• v.3 no.1
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• pp.74-100
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• 1989

Inspite of the lots of studies on the harmfulness of cigarette smoking to the body published by many researchers since 1950, cigarette smoking people are increasing in number especially, cigarette smoking by young and women causes a serious problem. Examining the physiological motives of youth shows that, impulse which the youth want to immitate the adults, alluring curiousity, and defiant physiology of escaping from the norm of traditional groups which has been banned are cooperated well compoundly. As the period of the youth is the one which they accumulate knowledge and charactor by learning as well as the period of growth mentally, and physically they should be rightly educated about smoking before they addicted to smoking and it is desirable for us to make the youth to understand how harmfully the smoking is to effect to their growth and mental soundness simply not as a social norm which they should not smoke. The main motive of this study on the attitude of smoking by the youth is to give basic materials related on this field. For this study, 647 questionnaires were used as studying material which were able to analyze among 720 questionnaires of 2 classes of each grade of 3 high schools among the high schools of boys, girls and co-educated in Seoul from Oct. 21, 1988 through Oct. 26, 1988. Study Instrument are graded in Likert's 5 point from 40 questions which are 20 questions m affirmations and 20 questions in negations after analyzing the factors on 60 simple sentence questions which the students showed in preliminary studies. And these are systemized to be measured from 1 point which means they think smoking IS very bad to 5points which means they think smoking is really good. In these collected materials, technical statistics of frequency. percentage, average, standard deviation are used for general character and smoking attitude, $X^2-test$ for examinning Independant variables of physical. emotional, ethical and other areas pearson's coefficient of correlation for related direction and degree" and step­regression analysis for the degree of relative contribution of all variables which effect smoking attitude. The results of this study are as follows; 1. The smoking attitude of high school boys and girls showed average of 1.78 in physical area, 2.63 in emotional area, 2.61 in ethical area, 2.29 in other area respectively in a negative attitude generally also the negative attitude are expressed most strongly in physical area. I've can also say by this results that smoking is harmful to their health and further more it can be judged that this proves the youth in the period of preparation be adults have a strong curiousity in the emotional, ethical and other areas. 2. The most influential variables in each field as related factors effecting smoking attitude of the student can be explained from 13.2 in physical area the lowest experienced variables to 25.2 in emotional area the highest of degree of smoking experience. The fact that the more the smoking experienced students are increasing in number the higher tendency which accept the' smoking tells as the importance of health education about the population of latest student's smoking as important variables shown equally in each area. Those of grade, age, numbers of smoking people in house are showed meaningful in pure interrelation. Those related to the acceptance of teacher's smoking, sex, mothors education are shown meaningful in opposite interrelations. This means that the' increasing number' of smoking people in grade age, the number of smoker in family have a affirmative attitude. And people who are not interested in teacher's smoking wants to quit it, and whose mother's education is higher have a negative attitude. 3. The most negatively answered questions of the smoking attitude In physical, emotional, ethical and other areas are as belows; Firstly too much smoking is harmful to our health is 1.12 point. Secondly smoking have a ill-effect on pregnancy and embryo is 1.13 point. Thirdly smoking is harmful· to our health is 1.27 point. Fourthly smoking in crowed area with the people such as In a bus or subway should be prohibited is 1.27point. Fifthly smoking can ruin lungs is 1.31 point. And the most affirmatively answered questions are also as below; Firstly we showed smoke depending on time and place is 3.96 points. Secondly smoking is just habit is 3.83 points. Thirdly smoking people seem to be unable and deplorable is 3.69 point. Fourthly smoking should be prohibited by law is 3.56 points. Fifthly high school student's smoking is immitation of adults is 3.52 points.

• The Journal of the Korea Contents Association
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• v.15 no.5
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• pp.639-650
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• 2015

The purpose of this study was firstly, to explore the acceptability and acceptance intention of parents for smart animal toys and secondly, investigate whether there is a difference by sex and age. For this purpose, the questionnaire survey was conducted with 344 parents of younger children in Seoul and Gyeonggi Province. As a result, there were significant positive correlations among the relative advantage, aesthetics, social image of smart animal toys, the attitude of the new technology and the parents' acceptability. Whereas there were significant negative correlations among the acceptance risk and the parents' acceptability. The parents' acceptability showed differences in the relative advantages and social image according to the age of the parents and no significant difference according to purchasing experience of smart animal toys. These results indicated that the parents' acceptability and acceptance intention of smart animal toys were similar with the adoption process of innovative products or smart devices. And it was also informed that the most impact factors on parents' acceptance for smart toy were the relative advantage, social image, and the attitude of the new technology. This research will be useful in understanding parents purchasing intention of smart toys and provide valuable implication for smart toy companies, manufacturers, and developers.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.6
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• pp.637-643
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• 2010

In this study, we developed a Portable Multi-sensor System, which consists of a video camera, a GPS/MEMS IMU and a UMPC to acquire video images and position/attitude data. We performed image georeferencing based on the bundle adjustment without ground control points using the acquired data and then evaluated the effectiveness of our system through the accuracy verification. The experimental results showed that the RMSE of relative coordinates on the ground point coordinates obtained from our system was several centimeters. Our system can be efficiently utilized to obtain the 3D model of object and their relative coordinates. In future, we plan to improve the accuracy of absolute coordinates through the rigorous calibration of the system and camera.

• Journal of Astronomy and Space Sciences
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• v.11 no.2
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• pp.308-319
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• 1994

We can launch satellites only at a certain time which satisfies special conditions, since the current techniques cannot overcome these constraints. Launch window constraints are the eclipse duration, solar aspect angle, attitude control, launch site and the launch vehicle constraints, etc. In this paper, launch window is calculated that satisfies all these constraints. In calculating launch window, the basic concepts are relative locations of the sun-satellite-earth system and relative velocities of these, and these requires geometric consideration for each satellite. Launch window calculation was applied to Kitsat 2(low earth orbit) and Koreasat(geostationary orbit). The result is shown in the form of a graph that has dates on the X-axis and the corresponding times of the given day on the Y-axis.

• Korean Management Science Review
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• v.19 no.1
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• pp.197-224
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• 2002

Our study focuses on the implementation of IS development methodology as the innovation of IS organization. We have two main research objectives. We Intend to understand the critical factors affecting the implementation process of IS methodology. We also intend to deeply analyze the relationship among the implementation processes of methodology. The whole innovation process is divided into detailed four levels tilth dynamic and evolving Point of clew a cognition level, an adoption level, an acceptance level and an usage level. The results of our study are as follows. The main factors affecting initiation level of the IS methodology are the innovativeness of IS members, the existence of champion manager, training, the existence of IS performance gap, executive supports for IS organization, and the relative advantage of IS development methodology At the Implementation level, It is understood that the existence of champion manager executive supports, training and the relative advantage of innovation are the main factors. However, the complexity of Innovation is a megative factor about the quality of accepting and using the methodology In Innovation process. In performing the Innovation process, the Previous level gives very notable affection to the continuous next level. However it's also understood that positive attitude of adoption level does not directly affect the quality of using Innovation. Therefore, IS managers must pay attention to manacle each level of the Innovation Process to successfully accomplish the Implementation of IS methodology.

• The Journal of Information Systems
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• v.27 no.2
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• pp.53-75
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• 2018

Purpose The purpose of this study is to provide implications by examining the factors affecting the consumers' innovation resistance and intention to use FIDO technology based on the innovation resistance model. In addition, we investigate the difference between FIDO group using biometric authentication technology and those using knowledge / possessive authentication technology. Design/methodology/approach This study investigated the factors influencing innovation resistance and intention to use based on the innovation resistance model. And the structural equation model was applied to analyze the effect of innovation resistance and intention to use. Findings According to empirical results, this study found that perceived relative advantage (+), perceived risk (+), perceived complexity (+), and existing product attitude(+) influenced innovation resistance, and perceived relative advantage (+), self efficacy(+), and innovation resistance(-) influenced intention to use. In addition, this study found that there is a significant difference between the group using the bio-based authentication technology and the group using the knowledge / possessive based authentication technology.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.2
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• pp.165-170
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• 2002

For the inaccessible area where the field verification is unable, it is difficult to obtain the ground control points (GCPs) or the acquired GCPs may be inaccurate. In general systematic geometric correction is achieved by utilizing orbit ephemeris and three axis attitude data of the satellite. however, this method results to poor accuracy of the imagery's absolute coordinates. To improve the absolute accuracy as well as the relative accuracy, we added the accessible region into the inaccessible area. We obtained GCPs in the accessible region by the fast static GPS survey and made geometric corrections with these biased GCPs. Because the biased GCPs show a pattern of coordinate errors, we analyzed this tendency to track the estimated errors in the inaccessible area.

• Journal of Families and Better Life
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• v.34 no.3
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• pp.65-84
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• 2016

This study examined the factors that were associated with longitudinal changes for ten years from 2004 to 2014 in time spent on housework by married couples who had a preschooler as their first-born child. It also sought to figure out how much of such temporal changes were attributable to differences in the means on associated factors as well as to differences in the influence or slope of such factors. A total of 9,668 time diaries from the Korean Time Use Survey were used to analyze the influence of couple's weekly work hours, wife's relative income, couple's education and gender role attitudes on the time spent on housework of husbands and wives. Results from descriptive statistics, regression and decomposition analysis were as follows. First, women decreased, while men increased their time doing housework. Second, weekly work hours of husband and wife were related to their time doing housework in every year surveyed. Third, wife's relative earnings and couple's gender role attitudes affected wife's time doing housework more than husbands', whereas couple's education had stronger effects on husbands than wives. However, such influence was apparent on a certain survey year, and then disappeared in another, or became stronger or weaker longitudinally. Fourth, the temporal decrease in wife's housework time and increase in husband's housework time were attributable to social and cultural changes such as reduced working hours, rising female income, higher educational background, and prevalence of egalitarian gender role attitudes. Findings suggest that the trend in spending time on housework is expected to continue, and provide a timely policy implications to facilitate the change.