• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.557-564
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• 2002

Discharge capacity test is carried out to find out influencing factors on discharge capacity of prefabricated horizontal drains to improve weak dredged clay. Four representative prefabricated horizontal drains are selected based on the size of drain as well as the shape of core. Test is carried out for 10 days at each three level of confining pressure for all drains. Effects of elapsed time, confining pressure, hydraulic gradient and strength of filter and core on discharge capacities are examined. It is found that discharge capacity of drain, which has deformable core or has a possibility of squeezing filter into core, decreases more with time due to its low strength. As confining pressure increases, discharge capacity decreases due to the squeezing of filter into core.

• Proceedings of the Korean Reliability Society Conference
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• 2005.06a
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• pp.121-129
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• 2005

In this paper, we consider a periodic preventive maintenance(PM) policy in which each PM reduces the hazard rate of amount proportional to the failure intensity, which increases since the last PM and slows down the wear-out speed to that of new one. And the proportion of reduction in hazard rate decreases with the number of PMs. Our model is similar to $ARI_1$ proposed by Doyen and Gaudoin(2004) in the sense of reduction of hazard rate. Our model has totally different wear-out pattern of hazard rate after PM's, however, and the proportion of reduction depends on the number of PM's. Assuming that the system undergoes only minimal repairs at failures between PM's, the expected cost rate per unit time is obtained. The optimal number N of PM and the optimal period x, which minimize the expected cost rate per unit time are discussed. Explicit solutions for the optimal periodic PM are given for the Weibull distribution case.

• Korean journal of food and cookery science
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• v.19 no.5
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• pp.546-554
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• 2003

This study was designed to identify the take-out food usage of university students in Seoul and Gyeonggi-do. Questionnaires were used to analyze these habits among 500 respondents. 1. The Frequency of Take-Out Food use: the greatest proportion of students used take-out foods once or twice a week (33.8%). 2. The reasons for Take-Out Food use: fastness was the major reason (47.8%). 3. The day of the week for Take-Out Food use: the majority of the students used Take-Out foods regardless of the day (54.4%). 4. The time of day for Take-Out Food use: 6∼8 p.m. for 31.6%. 5. The cost spent in each meal: 51.6% spent 3,000 to under 5,000 won. 6. The menus of Take-Out Food used: coffee was the most popular of all the take-out foods (43.6%). 7. Points considered when buying Take-Out Food: the majority of the college students thought tastes and quality of the foods were the most important considerations (51.0%). 8. The source of information about Take-Out Food: 43.4% of the students obtained information from their friends.

• Journal of the Korea Safety Management & Science
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• v.6 no.2
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• pp.211-229
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• 2004

The basis of cyber trading has been sufficiently developed with innovative advancement of Internet Technology and the tendency of stock market investment has changed from long-term investment, which estimates the value of enterprises, to short-term investment, which focuses on getting short-term stock trading margin. Hence, this research shows a Short-term Stock Price Forecasting System on Learning Agent System using DTA(Decision Tree Algorithm) ; it collects real-time information of interest and favorite issues using Agent Technology through the Internet, and forms a decision tree, and creates a Rule-Base Database. Through this procedure the Short-term Stock Price Forecasting System provides customers with the prediction of the fluctuation of stock prices for each issue in near future and a point of sales and purchases. A Human being has the limitation of analytic ability and so through taking a look into and analyzing the fluctuation of stock prices, the Agent enables man to trace out the external factors of fluctuation of stock market on real-time. Therefore, we can check out the ups and downs of several issues at the same time and figure out the relationship and interrelation among many issues using the Agent. The SPFA (Stock Price Forecasting System) has such basic four phases as Data Collection, Data Processing, Learning, and Forecasting and Feedback.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.1
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• pp.79-95
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• 2016

In order to improve the Quality-of-Service (QoS) of latency sensitive applications in next-generation cellular networks, multi-path is adopted to transmit packet stream in real-time to achieve high-quality video transmission in heterogeneous wireless networks. However, multi-path also introduces two important challenges: out-of-order issue and reordering delay. In this paper, we propose a new architecture based on Software Defined Network (SDN) for flow aggregation and flow splitting, and then design a Multiple Access Radio Scheduling (MARS) scheme based on relative Round-Trip Time (RTT) measurement. The QoS metrics including end-to-end delay, throughput and the packet out-of-order problem at the receiver have been investigated using the extensive simulation experiments. The performance results show that this SDN architecture coupled with the proposed MARS scheme can reduce the end-to-end delay and the reordering delay time caused by packet out-of-order as well as achieve a better throughput than the existing SMOS and Round-Robin algorithms.

• Journal of Institute of Convergence Technology
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• v.2 no.2
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• pp.13-19
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• 2012

This Design research is a design of rescue equipment combined with beach garbage can for prompt rescue at the time of the accident in water. As a usual, it is used as garbage can hanging a garbage bag on the holders located in both sides, and it can be used to rescue drowning men promptly taking out a rescue tube located inside of the equipment at the time of the accident in water. Support is consisted of beach one, wall-hanging one and pipe one, and it could be installed to match the situation because it can be combined with all main frames. As a usual, it is used as garbage can in seaside, but it can be used to rescue drowning men promptly taking out a rescue tube after pulling the handle located in front of main frame at the time of the accident in water, and it can be used to pull drowning men out of the water because rope is kept in rescue tube.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.1
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• pp.10-15
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• 2000

Evaluation of long term stability of the Brinell standard hardness tester was carried out to secure its application as a national standard in Brinell hardness. Accuracy and repeatability in load application were tested through evaluating errors in hardness measurement of certified reference blocks. All of those requirements in KS as well as ISO specifications were satisfied by this standard hardness tester. In addition to this, long term stability test of automatic indentation measurement system was carried out. The scattering range was almost the same with its error range. To figure out an optimum test condition for better repeatability and long term stability, the effect of load variation, load application speed and time have been studied using orthogonal array experimental plan. It was found that the best combination is $30{\mu}m/s$ of load application speed and 25 seconds of load application time.

• Textile Coloration and Finishing
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• v.16 no.1
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• pp.40-47
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• 2004

Alkaline treatment gives Sea-Island type yam to produce microfiber and silk-like touch. But this treatment have some problems in dyeing and finishing process. To solve some problem occurred in dyeing and finishing of polyester fabric, the ultrasonic treatment technique was used recently. This study was carried out to confirm the effect of the ultrasonic treatment on alkaline weight loss finishing of polyester fiber under general alkaline treatment conditions; NaOH concentration 2, 3, 4, and 5％, treatment time 5, 10, 15, and 20 minutes, treatment temperature 70, 80, 90, and 99'E, respectively. On the other hand, the three way lay out method was used to test of significant obtained data from alkaline treatment. It was found that weight loss increased with increasing the NaOH concentration, temperature, and time. Also, in case of PET/Co-PET fabrics by ultrasonic, weight loss and dissolution of microfiber were superior to PET/Co-PET fabrics without ultrasonic. Tensile strength and modulus decreased with increasing NaOH concentrations and hydrolysis time. Therefore, the effect of alkali hydrolysis by ultrasonic application was better than that of the conventional method.

• Journal of Environmental Health Sciences
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• v.30 no.2
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• pp.65-70
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• 2004

Hair is based upon the skin which enroll the body of high living animals and have multiple membrane structure. This study were used rats and carried out to find out the effects of commercial permanent wave products to skin which are composed of thioglycolic acid and bases. Results were as follows. Permanent wave penetrated to 3 hours later with steady state in skins and was not significant changeable after 20hr later. In case of neutralizer with thioglycolic acid lag time and permeability coefficient in healthy skin were 3.38hr and 0.96$\mu\textrm{g}$/$\textrm{cm}^2$/hr, in old skin were 3.14hr and 0.l28$\mu\textrm{g}$/$\textrm{cm}^2$/hr, and in wounded skin were 3.08hr and 0.157$\mu\textrm{g}$/$\textrm{cm}^2$/hr. In conclusion, lag time and permeability coefficient in old skin and wounded skin were faster than healthy skin. In vivo which was studied by general time and method of permanent wave. We found out that fine rinkle and rash of skin were changeable in the case of treating with permanent wave drugs than normal skin. Also, permanent wave drugs could induced rash and eruption at the skin by the naked eye.

• Korean Institute of Interior Design Journal
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• no.34
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• pp.61-68
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• 2002

It aims to understand how the time can be expressed in architecture from viewpoints of Oriental and Western philosophy. We just have done sporadic studies such as historical time, physical time, specific time, time as the space-time continuum and appreciation time. It`s impossible to find out that time exactly is since `time` is ambiguous. Because the meaning is formed newly by relational changes between visible and invisible existing thing. In such point of view, this study attempts at analyzing the inter-relationship between the art, music, architecture and time-concept in oriental and western philosophy. A comparative study follows : Time can be classified into the linear concept of time & the cyclic concept of time in an agricultural civilization and oriental philosophy. Linear concept of time can be divided into 1)the inevitable concept of time and 2)the 4-dimensional concept of time and 3) the indefinite concept of time.