• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.281-291
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• 1999

Productivity of container cranes and gantry cranes is influenced by the performance of crane hardware and cycle time. Cycle time in container handling is influenced by the path of containers and relative positioning of containers. So we have to minimize the sway of containers and spreaders to minimize relative positioning time. And sway minimization is influenced by the skill of workers in manual gantry cranes. In this paper, we will develop anti-sway system using mechanical and electrical method. Proposed hybrid system uses the basic structure of general manual gantry crane. So, it is very useful and effective. Electrical methods are main methods and mechanical methods are auxiliary methods.

• Journal of Astronomy and Space Sciences
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• v.32 no.4
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• pp.387-393
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• 2015

This study presents a precise relative navigation algorithm using both laser and Global Positioning System (GPS) measurements in real time. The measurement model of the navigation algorithm between two spacecraft is comprised of relative distances measured by laser instruments and single differences of GPS pseudo-range measurements in spherical coordinates. Based on the measurement model, the Extended Kalman Filter (EKF) is applied to smooth the pseudo-range measurements and to obtain the relative navigation solution. While the navigation algorithm using only laser measurements might become inaccurate because of the limited accuracy of spacecraft attitude estimation when the distance between spacecraft is rather large, the proposed approach is able to provide an accurate solution even in such cases by employing the smoothed GPS pseudo-range measurements. Numerical simulations demonstrate that the errors of the proposed algorithm are reduced by more than about 12% compared to those of an algorithm using only laser measurements, as the accuracy of angular measurements is greater than $0.001^{\circ}$ at relative distances greater than 30 km.

• Journal of Environmental Science International
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• v.26 no.5
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• pp.585-590
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• 2017

The Diameter at Breast Height (DBH) provides information about the volume growth of a tree. In this study, we estimated the relative growth rates of Castanea crenata and Pinus rigida as 4.07% and 3.73%, respectively. Although the difference was low, we demonstrated that the growth rate of C. crenata is slightly faster than that of P. rigida. After calculating the relative growth rate for each section, we found that the relative growth of C. crenata decreased with time. However, the relative growth rate of P. rigida showed an overall increase. The gap widths of both species showed an increasing trend. However, the gradient of the two species was different. The gradient of C. crenata was approximately 12.0, but that of P. rigida was approximately 4.7. This means that the volume growth of C. crenata was faster than that of P. rigida during 4 years. However, this was relatively a short period for measuring the volume growth pattern, and we believe that additional useful information can be obtained by conducting long-term ecological monitoring. Results of canonical correspondence analysis showed that among the climate variables, temperature was significantly related to the gap widths for both species.

• Journal of Family Resource Management and Policy Review
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• v.21 no.2
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• pp.51-72
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• 2017

The purpose of this study was to identify perceived work-family conflict of married working women and men with children under 12 years. Specifically, This study attempts to examine the differences of relative influence between objective time variables and subjective satisfaction variables unlike previous research. For research, this study used the data of 1012 working men and women from the 3rd Nation survey of Korean Family in 2015. The main results of this study were as following. First, Business hours and cognition of enough leisure time had more relative effect of work${\rightarrow}$family conflict than any other variable. On the other hand, leisure time on weekdays had the effect of family${\rightarrow}$work conflict with women and men. Second, gender differences of work${\rightarrow}$family conflict and family${\rightarrow}$work conflict were identified. In work${\rightarrow}$family conflict, men were influenced cognition of enough leisure time, women were influenced couple conversation time and employment status unlike men. In family${\rightarrow}$work conflict, men were not influenced subjective satisfaction variables. But women were influenced satisfaction with division of child care. Third, in family${\rightarrow}$work conflict, the addition of objective time variables in Model of men resulted in an increased $R^2$-value, but in work${\rightarrow}$family conflict and family${\rightarrow}$work conflict, the addition of subjective satisfaction variables in Model of women resulted in an increased $R^2$-value.

• Korean Journal of Community Nutrition
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• v.9 no.5
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• pp.654-662
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• 2004

The purpose of this study was to assess the structure of the decision and the importance of the attributes in choosing food-related tour program. Questionnaires were developed in three languages- Japanese, Chinese, and English- given to 300 foreign tourists who have visited Korea in 2002. Statistical data analysis was completed using SPSS Win (ver 11.0) for descriptive analysis and conjoint analysis. The results of this study showed that the 'price' was the most important attribute (35.62%) in choosing a hypothetical food tourism program, followed by 'place' (27.35%), 'time' (26.01 %), and 'type of program' (10.22%). With respect to the relative importance values for each attribute by different groups, English- and Chinese-speaking tourists considered 'price' more than other factors, while 'time' was regarded as the most important factor for Japanese tourists. Therefore, it indicated the need to recognize the different needs among tourists and put these factors into consideration in developing the programs.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.3_4
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• pp.34-47
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• 1995

It is experienced fact as a regular annual event that the structure to he designed on unreasonable flood for the agricultural structures including reservoirs have been brought not only loss of lives, but also enormous property damage. For the solution of this problem at issue, this study was conducted to develop an optimal runoff hydrograph model by comparison of the peak flows and time to peak between observed and simulated flows derived by linear time-invariant and linear time-variant models under the condition of having a short duration of heavy rainfall with uniform rainfall intensity at nine small watersheds which are within the range of 55.9 to 140.7 square kilometers in area in Han, Geum, Nagdong and Yeongsan Rivers. The results obtained through this study can be summarized as follows. 1. Storage constants and Gamma function arguments were calculated within the range of 1.2 to 6.42 and of 1.28 to 8.05 respectively by the moment method as the parameters for the analysis of runoff hydrograph based on linear time-invariant model. 2. Parameters for both linear time-invariant and linear time-variant models were calibrated with nine gaged watershed data, using a trial and error method. The resulting parameters including Gamma function argument, N and storage constant, K for linear time-invariant model were related statistically to watershed characteristic variables such as area, slope, length of main stream and the centroid length of the basin. 3. Average relative errors of the simulated peak discharge of calibrated runoff hydrographs by using linear time-variant and linear time-invariant models were shown to be 0.75 and 5.42 percent respectively to the peak of observed runoff hydrographs. Correlation coefficients for the statistical analysis in the same condition were shown to be 0.999 and 0.978 with a high significance respectively. Therefore, it can be concluded that the accuracy of a linear time-variant model is approaching more closely to the observed runoff hydrograph than that of a linear time-invariant model in the applied watersheds. 4. Average relative errors of the time to peak of calibrated runoff hydrographs by using linear time-variant and linear time-invariant models were shown to be 16.44 and 19.89 percent respectively to the time to peak of observed runoff hydrographs. Correlation coefficients in the same condition were also shown to be 0.999 and 0.886 with a high significance respectively. 5. It can be seen that the shape of simulated hydrograph based on a linear time- variant model is getting closer to the observed runoff hydrograph than that of a linear time-invariant model in the applied watersheds. 6. Two different models were verified with different rainfall-runoff events from data for the calibration by relative error and correlation analysis. Consequently, it can be generally concluded that verification results for the peak discharge and time to peak of simulated runoff hydrographs were in good agreement with those of calibrated runoff hydrographs.

• Journal of The Korean Association For Science Education
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• v.2 no.1
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• pp.31-51
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• 1980

In order to research into the devel of the concept of movement and speed in our own way and compare with the Piaget's method, and then find out the formative period of such development, we have put the 192 primary school children as the model and obtained the following results. 1. As their grade upyards, all the experimental subjects showed the gradual progress generally regardless of sex or regions, while only the relative speed showed irregular progress. 2. There was no experimental subject which showed any remarkable sexual characteristics. But in the relative movement, the lower grade boys and higher grade girls made progress. In the subjects of circulation movement, intuition of speed, relative speed and speed of simultaneous movement, the boys marked better progress, whilst the girls were advanced a little in the speed of continuous movement with, different distance and time. 3. There was no conspicuous difference between the urban and rural areas, except a slight tendency that the urban children made better progress in the change of progressing direction, native continuous procedure of periodical movement, travelling road, and the speed of continuous movement with different distance and time whereas the rural children were more advanced in the relative movement, relative speed and intuition of speed. But it should be 'taken into consideration that the rural regions in our case were relatively developed in comparison with the traditional rural communities, which may explain about little regional difference. 4. Comparing our research results with the Piaget's theory, we have reached below results. Our research reports that the formative period of the conception of the problems of diverse progressing direction and a native continuous procedure of periodical movement was simultaneous, at the Piagetian level(at the fourth grade) which coincides with Piagetian theory. The travelling road should be made up a little lower at 2A/2B according' to Piagetian Level, whereas it was formed at the 4th grade as shown in our previous research. Intuition of speed should belong to the prior stage to concrete operation, but our research shows it was formed late at the 4th grade. Composition of displacement was made at the 6th grade, and it was almost equal to the first stage of formal operation(3A). But in the subjects of relative movement relative speed, the speed of continuous movement with different distance and time, relation and preservation of invariable speed, and accelerated motion, even 6th grade children marked a poor record. Summed up, the procedure conception as a basic movement conception coincides with the Piagetion level. But as for speed intuition, relative speed and speed fixation, it was Jar behind Piagetian level. Therefore it is required that we have to concentrate on the systematic training in these parts on the spot.

• Health Policy and Management
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• v.11 no.2
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• pp.58-84
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• 2001

This study was conducted to explore the relationship between the efficiency and its organizational determinants of tile Community Mental Health Centers(CMHCs). Data are obtained from 81 personnel of 27 CMHCs from Sept. to Oct. in 1999(19 in Kyunggi province, 7 in Seoul City and 1 in Chunchon, Kangwon province). Major findings of this study are as follows. 1. DEA is a mathematical programming technique that optimizes the relative efficiency ratio of inputs over outputs for each decision-making unit(DMU). It produces a summary scalar efficiency ratio for each DMU of CMHCs. It assessed multiple inputs and multiple outputs simultaneously, and compared to specific peer group of CMHCs. 2. Organizational determinants of DEA efficiency of CMHCs we proved as advertisement(＋), location of CMHCs(in public facility)(＋), area of facility(＋), period of operation(＋), job satisfaction(＋), clarity of work-role(vague), cohesion(－), rate of certified personnel(＋), number of referral(＋), and voluntary service time(－).

• Journal of Korea Society of Industrial Information Systems
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• v.26 no.5
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• pp.37-54
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• 2021

In this study, a customized model (CM) for the efficient operation of cold chain logistics considering the hypergeometric distribution is proposed. The CM focuses on the segmentation market of ready-to-eat foods and juices made from fresh materials. Companies should determine the amount of production by predicting consumer preferences and quantity to ensure high-efficiency production. The CM is represented as a mathematical formulation and implemented using the genetic algorithm (GA). Addition, the relative weights of CM are calculated. Further, the calculated weights are applied to the GA. In the numerical experiment, hypergeometric distribution is used to calculate the relative weights between the range of production quantities and the customized amount. Experiment results are the values of relative weights and the comparison results by average values of handling cost, total cost and CPU time. Finally, the significance of this study is summarized and a future research direction is remarked in conclusion.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.47-48
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• 2015

VTSO make a decision which one will be danger and what to expect ship's actions due to each encountering situation with CPA(Closest Point of Approach) and TCPA(Time to Closest Point of Approach) by monitoring ship's vectors(Course & Speeds) in real-time through the VTS system. This study is the fundamental research for developing algorithm and system that does not decide the collision risk in one's own ship's viewpoints, but it identifies the related ships into danger through the third party(VTS ) in real time.