• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.239-243
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• 2008

The fluctuation of inlet flow to a water treatment plant makes a serious problem that it can change the outlet flow-rate from each process abruptly, and ultimately occur the detachment of the attached particles inside each unit process. Also, since it takes very short time for the surface wave occurred from the fluctuation of inlet flow to reach the latter processes, it is impossible for operators to cope with that stably. Therefore this study was conducted to suggest the methodology for accurately predicting the travel time of surface wave occurred from the fluctuation of inlet flow to reach the latter process. Through the experiment, which was carried out for the full-scale water treatment plants(capacity : 2,000m3/d), it could be confirmed that the flow rate fluctuation from equalization tank produce the surface wave. And the wave transfer velocity is a function of the hydraulic radius and the length of each open type tanks which are comprised in the latter processes.

• Journal of Wetlands Research
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• v.3 no.2
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• pp.119-131
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• 2001

This study uses HEC-RAS for the quantitative aspects and the QUAL2E model for the qualitative aspects of the flow of urban streams, where the natural recovery system is applied. The instream flow of the small streams is estimated using the numerical model by verifying the existing data with the acquired data. The characteristics of the model reach place more weight on the drought discharge around the ordinary discharge, and this is caused by the natural recovery system that maintains the existing bank. The data of direct discharge to the sewage treatment plant through the inception pipe, BOD, DO, temperature, and so forth, are the official data from the department of environment. Considering the characteristics of small streams, the factors for the QUAL2E model are estimated with the focus on the hydraulic conditions and the stream view. This study proposes the future improvements for the natural recovery system by investigating the practical use of the waterfront and the application of the proper instream flow. Also, the hydraulic and hydrological investigation of the covering rate by the natural vegetation and the meandering by the varying river way is performed.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.2
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• pp.280-288
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• 2003

We need refrigeration system which can maintain the freshness of agricultural products, because of being distance from a tiller to a consumer. Vacuum Pre-cooling system has an advantage in quality maintenance through vapid cooling down by using latent heat of evaporation of stored products. A number or thawing methods in current use have also several disadvantages in thawing time. discoloration mass loss caused by drying, capital costs and running cost. These damages are, it is claimed, either eliminated or improved by the vacuum thawing system. An experimental study on the pre-cooling for the bean sprouts and cabbage, and thawing for hairtail and croaker by the low temperature vacuum system were carried out. The cabbage cooling time with this Pre-cooling vacuum system took about 60 minutes to reach from $23.2^{circ}C to 4.5^{\circ}C$ at 5 mmHg abs. ($6.66\times10^{-4}$ MPa). The croaker thawing time with this low temperature vacuum thawing system took about 170 minutes to reach from $-10.3^{circ}C to -0.8^{\circ}C$ at 20 mmHg abs ($2.67\tiems10^{-3}$MPa). The vacuum Pre-cooling and thawing system have merits compared with present systems in their short intervals to cool down and to thaw without any quality losses.

• Education of Primary School Mathematics
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• v.4 no.2
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• pp.139-150
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• 2000

The objectives of the current study are first, to compare and analyze the two different teaching methods of elementary mathematics in the traditional method and in the constructivists view, and, second, thereby to reveal possible problems of the present teaching practice and to suggest some guidelines to solve those problems.The results of this research are as follows: First, longer time was spent to reach the target pont of class because the class was a little bit disturbed and noisy due to a large amount of student activities in the beginning of the class in the constructive view. Second, in the class in the constructive view, the teacher should be able to respond appropriately to the situation where the students were cognitively. And the teachers sufficient preparation for the class was found essential to have the students reach the target point by themselves through identifying children`s minds. Third, the class in the constructivists view provide the teaching environment were the teacher could evaluate each students ability accurately and study progress of the class. And fourth, finally, it was not easy for the teacher to pay attention individually to each student in the current situation of large class, The effort to have more concern for students seems to contribute to opening student`s closed minds and to forming positive attitudes toward mathematics.

• Journal of the Korean Institute of Landscape Architecture
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• v.24 no.3
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• pp.79-95
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• 1996

The traditional gardens of China were constructed on the basis of the common aesthetic consciousness between designers and users. As designers and users communicated each other through the medium of garden, they give suggestions to our design and appreciation of modern landscape architecture. The traditional gardens of China pursued to reach the state of Yi Jing(意境), and this state formed the keynote of the whole field of Chinese culture. Yi Jing is the aesthetic theory originated in Pre-Qin Era, and established in Tang-Dynasty. After this, this theory become the very important aesthetic category of Chinese aesthetics. Yi Jing is the process from conception to appreciation, and requires the three parts of designer, a work of art, and appreciator. To reach Yi Jing, designers must be well grounded and persevere in their efforts. They also had to have the ability of corresponding the inner order of environment and landscape, and expressing their own feelings and emotions into gardens. So ultimately, they were in pursuit of constructing the gardens as if something naturally created. The garden itself is the meeting place of designers and users. The space in which users can think of life, nature, history, and cosmos. In order to do this, designers design the real landscape and non-visual landscape. This design can give appreciators more fertile imagination. Appreciation perfects the Yi Jing of gardens. Yi Jing is created by co-work of artist and appreciator with common aesthetic consciousness and sense. Therefore, it is subjective, and it may be vary with man and time.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2S
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• pp.608-620
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• 2000

A web based E-mail system consists of serves which supply mail accounts and service, and clients which take part of interfacing with users. The web browsers such as Netscape Navigator and Internet Explorer are the popular clients. Users who cannot afford to get an E-mail id in general mail servers are, therefore, able to reach a e-mailing service in the web environment by using client programs in connection with a mail server. Although the quality of service has been upgraded a lot in recent days, it doesn't provide with satisfactory services anymore. In this paper, we intend to design a mail agent system based on the web environment. Through this system we could reach a convenient user interface based on Internet Explorer and could easily access administratory environment on the basis of NT Server 4.0. Using the service engine dominent in mail agent system, it could provide with convenient user interfacing tools like responding the absence of users, mail filtering and refusing messages, etc. And it would ultimately make possible a constant system security, by preventing system failure phenomena caused by extraordinary uses beyond its capability.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.22 no.2
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• pp.76-88
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• 1996

The facial color is affected by age increase, health condition, internal and/or external environment factors and so on. Especially, the external environment factors in accordance with the influence of environment pollution that is air pollution, exert a bad influence of skin. The object of this study shall be quantified the facial color change in accordance with age increase, external environment factors. Therefore we have make the measurement about the facial color change of Korean women by regional groups. We've quantified through correlation equation, the rate of the many external environment factors which influence the facial color change (air pollution, climate condition, season etc.) As the result of the study, we have reach to know that CO, $O_3$, $NO_2$ has high relation with hue, value, chrome change. The facial color change is proved to be influenced atmospheric environment condition. Besides in hue and value in relation with meteorology demonstrates its link with the temperature, the evaporation quantity, the duration of sunshine of each region. Therefore we have instill cognition of the environmental pollution in accordance with external environment factor that was quantified. And we have reach to know this study affects cosmetics development of new concept.

• Journal of the Korea Safety Management & Science
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• v.11 no.1
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• pp.43-49
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• 2009

This study set three kinds of situation and observed the various states such as carbonization by experimenting damages by fire of electric iron. The results of this study are as follows: The fire did not occurred when the unpowered iron over mattress and cotton shirts was com busted completely by external flame because the temperature of surface of soleplate and mattress did not reach the minimum ignition energy and when the powered electric iron over mattress and cotton shirts was left for an hour with its temperature dial set to high because the temperature of combustibles did not reach the minimum ignition energy. The fire occurred when the electric iron in which the outer box, bi-metal switch, and temperature fuse were removed over mattress and cotton shirts was powered by through heater terminal, and then the electric iron, mattress, and cotton shirts were combusted by the fallen combustibles because the temperature of combustibles reached to the minimum ignition energy with the help of active transfer of heat.

• Journal of International Academy of Physical Therapy Research
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• v.8 no.2
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• pp.1182-1189
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• 2017

The purpose of this study was conducted with senior women of ages 65 in Community Center to identify effective exercise methods for preventing falling accidents by enhancing balancing skills through aerobic and foam roller exercise programs. There were 24 subjects : 11 aerobics group and 13 foam roller group. 30 minute exercise programs were conducted against both groups 12 times 6 weeks. Various tests, including Time up and go test, Forward reach test, One-leg standing with eyes open/closed and Y-Balance were conducted prior to commencing the exercise program. Wilcoxon's Signed-ranks test was executed to analyze the changes in balance of the aerobic and foam roller exercise group prior to and after the experiment, and Mann-Whitney test was executed to compare the difference between the two groups. The Y-Balance(post. medial) show statistically significant differences in the amount of change before and after exercise between the two groups, except for Timed up and go test, Forward reach test, Y-Balance(ant.), and Y-Balance(post. lateral), which did not showed statistically significant difference (p<0.05). Foam roller exercises are effective methods to enhance the balancing skills in senior women to prevent falling accidents.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.5
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• pp.471-478
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• 2011

This UGV (Unmanned Ground Vehicle) is not only widely used in various practical applications but is also currently being researched in many disciplines. In particular, obstacle avoidance is considered one of the most important technologies in the navigation of an unmanned vehicle. In this paper, we introduce a simple algorithm for path planning in order to reach a destination while avoiding a polygonal-shaped static obstacle. To effectively avoid such an obstacle, a path planned near the obstacle is much shorter than a path planned far from the obstacle, on the condition that both paths guarantee that the robot will not collide with the obstacle. So, to generate a path near the obstacle, we have developed an algorithm that combines an edge detection method and a limit-cycle navigation method. The edge detection method, based on Hough Transform and IR sensors, finds an obstacle's edge, and the limit-cycle navigation method generates a path that is smooth enough to reach a detected obstacle's edge. And we proposed novel algorithm to solve local minima using the virtual wall in the local vision. Finally, we verify performances of the proposed algorithm through simulations and experiments.