• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.2
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• pp.49-55
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• 1982

The purpose of this study is to classify the factors influenced on the damages of head works suffered from the storm flood occurred on July 22 1980 in both Musim and Bochong rivers and to find out an integral counter measures against the causes influenced on the disaster of head works in the engineering aspect of planning, design, construction and maintenance. In this survey, number of samples was taken 25 head Works, and the counter measures against the causes of their disasters summarized was as follows, 1. In the aspect of planning a. As the flood water level after the establishment of head works is more increased than the level before setting of head works owing to having more gentle slope of river bed between the head works than nature slope of river bed. Number of head works should be reduced for the appropriate annexation of them b. In the place where head works is established on the curved point of levee, the destruction of levee becomes severe by the strong deflective current. Therefore the setting of head works on the curved point should be kept off as long as possible and in case of unavoidable circumstances the construction method such as reinforced concrete wall or stone wall filed with concrete and anchored bank revetments should be considered. 2. In the aspect of design a. As scoring phenomena at up stream is serious around the weir Where the concentration of strong current is present in such a place, up stream apron having impermeability should be designed to resist and prevent scoring. b. As the length of apron and protected bed is too short to prevent scoring as down stream bed, the design length should be taken somewhat more than the calculated value, but in the case the calculated length becomes too long to be profitable, a device of water cushion should be considered. c. The structure of protected river bed should be improved to make stone mesh bags fixed to apron and to have vinyl mattress laid on river bed together with the improvement for increasing the stability of stone mesh bags and preventing the sucked sand from the river bed. d. As the shortage of cut-off length, especialy in case of the cutoffs conneting both shore sides of river makes the cause of destruction of embankment and weir body, the culculation of cut-off length should be taken enough length based on seepage length. 3. In the aspect of design and constructions a. The overturing destruction of weir by piping action was based on the jet water through cracks at the construction and expansion joints. therefore the expansion joint should be designed and constructed with the insertion of water proof plate and asphalt filling, and the construction joint, with concaved shape structure and steel reinforcement. b. As the wrong design and construction of the weep holes on apron will cause water piping and weir destruction, the design and construction of filter based on the rule of filter should be kept for weep holes. c. The wrong design and construction of bank revetment caused the severe destruction of levee and weir body resulting from scoring and impulse by strong current and formation of water route behind the revetment. Therefore bank revetment should be designod and constructed with stone wall filled with concrete and anchored, or reinforced concrete wall to prevent the formation of water flow route behind the wall and to resist against the scoring and impulse of strong stream. 4. In the aspect of maintenance When the damaged parts occurred at head works the authorities and farmers concerned should find and mend them as soon as possible with mutual cooperation, and on the other hand public citizen should be guided for good use of public property.

• Research in Community and Public Health Nursing
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• v.12 no.3
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• pp.755-772
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• 2001

The specific purpose of this study was as follows: 1) To identify the level of sexual awareness and demand for sex education of teenagers, their parents and teachers. 2) To investigate the attitude toward and acceptance of heterosexual friendships by teenagers, their parents and teachers. 3) To identify the experience and direction of sex education of parents and teachers. For this purpose, this study selected 341 male and female teenagers at three high schools located in a city, 119 parents with high school students and 243 elementary/middle/high school teachers. The structured questionnaire was distributed to each of them and returned by them. This study was conducted over the period between June 1. 2001 and Aug 31. 2001. A total of 720 questionnaires were distributed to them and 703 were returned. Data analysis was conducted to obtain percentage and frequency using the SAS program. As a result, the following findings were obtained: Parents and teachers showed a similar attitude about sexual awareness, but teenagers showed a different attitude. In terms of the level of feeling of and interest in 'sex', teenagers, parents and teachers were comfortable in accepting it. As for sexual curiosity in puberty, 84.8% of the parents and 95.5% of the teachers responded that it was natural, whereas only 14.7% of teenagers responded that it was natural. But As for the item that 'sex is natural as one of human needs', 3.6% of the teenagers, 16.8% of the parents and only 1.2% of the teachers responded that it was not. As for the item that 'A man has a stronger sexual impulse than a woman', 6.1% of the teenagers, 16.8% of the parents and 17.3% of the teachers responded that it was not. 64.2% of the teenagers and 90.2% of the teachers responded that it was impossible to overcome the sexual impulse, whereas only 8.4% of the parents responded that it was possible. As for the item of masturbation, 64.5% of the teenagers responded that it was possible for male students and not possible for female students. 67.2% of the parents and 91.1% of the teachers responded that it was possible regardless of sex. As for the item of an attitude toward virginal purity, both the parents and teachers showed that virginal purity was important for both man and woman, but teenagers showed a weak awareness of virginal purity. As for the item, 'It is possible to have sexual intercourse with a lover during adolescence', 20.2% of the teenagers, 79% of the parents and 87.7% of the teachers responded that it was impossible. As for the item 'It is necessary to keep premarital virginal purity for a happy married life', 21.1% of the teenagers, 74.8% of the parents and 55.1% of the teachers responded that it was necessary, which shows that teenagers had a different opinion than parents and teachers. In case of pregnancy in adolescence, most of the responding teenagers, parents and teachers chose abortion. As for the item 'female refusal on male sexual approach', respondents accepted female refusal as they did for orders of teachers, parents and adolescents. As for item 'An assaulter is entirely to blame for sexual assault', all of three groups responded in the affirmative.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.5
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• pp.1525-1534
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• 2014

In recent years, the passengers are likely to decide their route on impulse due to the development of the integrated public transport system, and real-time information system. Especially, public transport fare integration in Seoul Metropolitan area, 2004 makes them not to have resistance about changing the modes or routes and their route choice is most effected by the degree of congestion. Assignment model have limitations to describe route changes by congestion. In this study, the concept of a link cost function used in road assignment and Effective frequency is introduced to describe the passengers' behavior when the capacity of public transport is over and the waiting time variation. Two situations, new transit line operation and accident, are set up to validate the model, as a result of the transit assignment by this model, the traffic on networks is not over the capacity. It is expected that this study will be of help to reflect the various behaviors in transit assignments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.267-280
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• 2017

The purpose of this study is to provide cosmetic companies and research institutes with basic data regardingthe development of marketing by making out the influence and characteristics of consumption. A total of 506 questionnaires were used as analysis for the questionnaire survey of twenty female college students who purchased cosmetics within sixmonths in Seoul and the metropolitan area. Consumption propensity varied characteristics depending on the degree of makeup, average number of purchases, main reason for using cosmetics, and where to buy cosmetics. Motivation for purchasing cosmetics varied characteristics depending on the largest skin problem, the degree of usual makeup, the average number of times cosmetics were purchased, and the main reason forusing cosmetics. The results revealed thepropensities of saving resources, planned purchases, consciousness to others, and impulse buying have significant effects on the cosmetic purchase motives of product conversion, being others-oriented, economicsand pursuing beauty(P<0.05).Consequently, this study hopes to contribute to the development of cosmetics companies and research institutes by providingbasic data forfuture development of productsas well as formarketing strategiesusing customer psychology by referring to various perspectives ofconsumer direction and desired purchase behavior.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.4
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• pp.52-60
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• 2015

Operation area of corps was expanded under military reformation, and extending range of 155 mm howitzer became important issue. New approach is needed to extend range to 80 kim. Ramjet engine is air breathing engine, and it can provide specific impulse several times more than solid rocket motor so that range is extended using same weight of propellant. If the ramjet engine is gun-launched system, it does not require any other booster because muzzle velocity is near Mach 3. Especially solid fuel ramjet (SFRJ) does not have any moving part so that it is favorable for gun-launching system which is under high stress during launching. In this paper, we design air intake, combustion chamber, and nozzle of 155 mm gun launched ramjet propelled artillery shell with inviscid flow assumption. We conduct parameter study to have range more than 80 km, and maximum high explosive volume.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.352-360
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• 2008

Recently Task Group (TG) 4 of the Institute of Electrical and Electronics Engineers (IEEE) 802.15a has been recommended a system with ranging capability in existence of multiple Simultaneous operating piconets (SOPs) as well as low-cost, low-power. According to the ranging service, coherent and non-coherent based ranging schemes using ternary code have been adopted as a standard. However it is hard to estimate an accurate time of arrival (TOA) in case of using direct sequence based TOA estimation method because pulse repetition interval (PRI) offered by TG is more limited than the maximum excess delay (MED) of channel. To mitigate inter pulse interference (IPI) problem, this paper proposes a non-coherent TOA estimation scheme using non-periodic transmission (NPT) pattern. The proposed receiver is based on a non-coherent energy detection considering with motivation of low rate wireless personal area network (LR-WPAN). TOA information is estimated via proper comparison with a prescribed threshold after the sliding correlation and search back window (SBW) process for reducing TOA error. To verify the performance of proposed ranging scheme, two distinct channel models approved by IEEE 802.15.4a TG are considered. According to the simulation results, we could conclude that the proposed scheme have performed better performance than the conventional method on the existence of multiple SOPs.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.1
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• pp.62-67
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• 2011

Nanoparticles-coated and impact-damaged carbon-fiber reinforced plastics(CFRP) laminates were tested under compression-after-impact(CAI) mode and the propagation of damage due to compressive loading has been monitored by acoustic emission(AE). The impact damage was induced not by mechanical loading but by a simulated lightning strike. CFRP laminates were made of carbon prepregs prepared by coating of conductive nano-particles directly on the fibers and the coupons were subjected to simulated lightning strikes with a high voltage/current impulse of 10~40 kA within a few microseconds. The effects of nano-particles coating and the degree of damage induced by the simulated lightning strikes on the AE activities were examined, and the relationship between the compressive residual strength and AE behavior has been evaluated in terms of AE event counts and the onset of AE activity with the compressive loading. The degree of impact damage was also measured in terms of damage area by using ultrasonic C-scan images. From the results assessed during the CAI tests of damaged CFRP showed that AE monitoring appeared to be very useful to differentiate the degree of damage hence the mechanical integrity of composite structures damaged by lightning strikes.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.4
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• pp.281-288
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• 2014

As a gas explosion is the most fatal accident in shipbuilding and offshore plant industries, all safety critical elements on the topside of offshore platforms should retain their integrity against blast pressure. Even though many efforts have been devoted to develop blast-resistant design methods in the offshore engineering field, there still remain several issues needed to be carefully investigated. From a procedure for calculation of explosion design pressure, impulse of a design pressure model having completely positive side only is determined by the absolute area of each obtained transient pressure response through the CFD analysis. The negative pressure phase in a general gas explosion, however, is often quite considerable unlike gaseous detonation or TNT explosion. The main objective of this study is to thoroughly examine the effect of the negative pressure phase on structural behavior. A blast wall for specific FPSO topside is selected to analyze structural response under the blast pressure. Because the blast wall is considered an essential structure for blast-resistant design. Pressure time history data were obtained by explosion simulations using FLACS, and the nonlinear transient finite element analyses were performed using LS-DYNA.

• The Korean Nurse
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• v.36 no.5
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• pp.91-100
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• 1998

This study aims to investigate smoking patterns in high school student and to give student smoker effective information. The sample of 250 male highschool students out of two different schools in Tae-Jon was questioned from July 10th to 15th. 1995. In analyzing these date. the statistics shows the realities by means of number of students. The results are summarized into 17 items as follows. Regarding the level of smoking. 140 students out of 250 admit that they have ever smoked. 52.1% of smoking students say that the motivation of beginning smoking is mainly curiosity. The survey shows that 22.9% of smoking students feel very good when smoking. It also shows that 30.0% of smoking students began smoking in the first grade of high school. With regard to the volume of smoking per day. 41.4% of smoking students smoke variably. 42.1% drink when smoking. 15.0% spend more than W 70.000 a month. About the question who knows the fact of their smoking. 51.5% answer that their friends know the fact of their smoking. In regard to the resaltionship between smoking and school per-formance. 18.2% of non smoking students make poor grades as compared with 40% of smoking students. 9.3% of smoking students say that they are satisfied with the school life. but 35.7% of them are not satisfied. Regarding the attitude to smoking teachers. 35% of smoking students state that they are affected by them. 69.3% of smoking students say that they will stop smoking. while the remaining 30.7% say that they will keep smoking. The reason of 63.9% to stop smoking is that smoking is bad for the health. The reason of 46. 5% to keep smoking is the acquired habit of smoking. 97.2% know the fact that the major element of cigarettes is nicotine and it is very harmful to the health. 40.8% recognize the harmful effect of smoking by TV and radio programs. 97.2% know that smoking could cause lung cancer. From the above results. I propose as follows We should make specific plan to keep smoking by simple curiosity from being developed into habitual smoking. We should teach them how harmful smoking is and make them stop smoking by themselves. It is very essential for family members and teachers to give continuous interest since childhood. As the teacher affect the students very much, they should give up smoking first. The incidence of smoking should be identified in each of the middle and high schools. smoking prohibition programs relevant to each school should be developed and implemented. The local community should ban cigarette vending machines. Cigarettes should not be sold to adolescents. By setting every place where adolescents gather including schools nonsmoking area. we should decrease their impulse to smoke. then smoking opportunities. and harmful effects to them caused by passive smoking.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.3
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• pp.141-147
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• 2019

Recently, the biggest issue in the electricity industry is the increase in renewable energy, and various technologies are being developed to ensure the capacity of the power system. In addition, super-grids linking power systems are being pushed to utilize eco-friendly energy between countries and regions worldwide. The HVDC transmission technology is required to link the power network between regions with different characteristics of the power system such as frequency and voltage. Until now, Korea has applied HVDC transmission technology that connects mainland and Jeju Island with submarine cables. But, the HVDC transmission technology is still developing for long-distance high-capacity power transmission from power parks on the east coast to load-tight areas near the metropolitan area. Considering the high population density and mountainous domestic environment, it is pushing for commercialization of the design technology of the ${\pm}500kV$ Double Bipole with metallic return wire transmission line to transmit large-scale power of 8 GW using minimal right of ways. In this paper, the insulation characteristics were studied for the design of double-bipole transmission tower with metallic return wire, which is the first time in the world. And the air insulation characteristics resistant to the various overvoltage phenomena occurring on transmission lines were verified through a full-scale impulse voltage test.