• Journal of Information Technology Applications and Management
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• v.9 no.4
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• pp.65-78
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• 2002

We propose a new application method of the datamining technique that might help building an efficient trade strategy in the stock market, where the analysis of the huge database is essential. The proposed method utilizes the association rules among the price changes of individual stock from the market basket analysis (a datamining technique typically used in the Marketing field) in building the strategy We also apply the proposed method to the daily stock prices in Korean stock market, from Jan. 2000 to Dec. 2001. The application results show that the proposed method gives an significantly higher yield rate than the actual stock chage rate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.283-285
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• 1997

We have obtained disordered carbon by pyrolyzing PPP in a nitrogen atmosphere for 8 hour at 700$^{\circ}C$. AC impedance property was measured with the PPP-based carbon/EC-DEC/Li cell. The impedance spectra of the cell were measured during the 1st discharge proceed. As the result of measurement the cell resistance decreased in intial discharge, but increase in final discharge.

• Journal of Chest Surgery
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• v.3 no.2
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• pp.153-157
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• 1970

The problembs of mitral reste'1osis following primary mitral comissurotomy for mitral stenosis have been increased gradually, and also its incidence of mitral restenosis has showed the increasing time by time. We report 3 cases operation.l of mitral restenosis among several cases which have followed primary operatioa for 254 cases of mitral stenosis from Jan. 1959 to Dec. 1969. at the department of thoracic and cardiovascuar surgery, Natioaal Medical Center, with a review of literatures.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1243-1251
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• 2017

When a Ship sails in the ocean, it is significant to find one's position for safe navigation. Most of ships have been using GPS navigation since its development after 1990's. The celestial navigation was used as the navigation method when sailing in the ocean, but time-consuming process such as complicated calculation and plotting the result on chart diminished its utilization. The thesis explains convenience and utilization of existing celestial navigation by resolving challenges it has. As a way of enhancing the celestial navigation, the author developed a software which incudes a numerical formula based on the previous calculation process. When a navigator inputs the altitude of sun, GHA and dec into computer while sailing, the position of the ship will be displayed as the coordinates. The improved method thus reaffirmed the usefulness of the celestial navigation and will greatly serve as means of navigation in the occurrence of distress. Abstract should be placed here.

• Geomechanics and Engineering
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• v.14 no.6
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• pp.545-552
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• 2018

Blast-induced ground vibrations by a significant amount of explosives may cause many problems for mining slope stability. Geological discontinuities have a significant influence on the transmission of dynamic pressure of detonation and according to their position relative to the slope face may have damaging or useful impacts on the slope stability. In this study, the effect of geological discontinuities was investigated by modelling a slope with geological discontinuities through applying the dynamic pressure in three-dimensional discrete element code (3DEC). The geological discontinuities in four states that generally apperceived in mine slopes are considered. Given the advantages of the pressure decay function defined by some researcher, this type of function was used to develop the pressure-time profile. The peak particle velocities (PPV) values were monitored along an axis by utilization of Fish programming language and the results were used as an indicator to measure the effects. As shown in the discontinuity-free model, PPV empirical models are reliable in rocks lacking discontinuities or tightly jointed rock masses. According to the other results, the empirical models cannot be used for the case where the rock mass contains discontinuities with any direction or dip. With regard to PPVs, when the direction of discontinuities is opposite to that of the slope face, the dynamic pressure of detonation is significantly damped toward the slope direction at the surface of discontinuities. On the other hand, when the discontinuities are horizontal, the dynamic pressure of detonation affects the rock mass to a large distance.

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.561-567
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• 2018

In this study, the electrochemical characteristics of Silicon/Carbon anode materials were analyzed to improve the cycle stability of silicon as an anode materials of lithium ion battery. Porous silicon was prepared from TEOS by the $st{\ddot{o}}ber$ method and the magnesiothermic reduction method. Silicon/Carbon anode materials were synthesized by varying the mass ratio between porous silicon and pitch. Physical properties of the prepared Silicon/Carbon anode materials were analyzed by XRD and TGA. Also the electrochemical performances of Silicon/Carbon anode materials were investigated by constant current charge/discharge, rate performance, cyclic voltammetry and electrochemical impedance tests in the electrolyte of $LiPF_6$ dissolved in organic solvents (EC : DEC = 1 : 1 vol%). The Silicon/Carbon anode composite (silicon : carbon = 5 : 95 in weight) has better capacity (453 mAh/g) than those of other composition cells. The cycle performance has an excellent capacity retention from 2nd cycle to 30th cycle.

• Journal of environmental and Sanitary engineering
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• v.8 no.1
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• pp.93-105
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• 1993

The major purpose of this study was to determine the effects of air pollution on respiratory diseases. From the analysis of $SO_2$, $NO_2$ and TSP levels measured at two air pollution monitoring stations(K & E area) of Seoul during Jan. 1988-Dec. 1990, pollution level of K area was higher than E area. Insurance out-patient records for the medical fee reimbusement submitted to the National Federation of Medical Insurance from Jan. to Dec. 1990 were used in order to assess the occurrence of respiratory disease. The results were as follows ; 1. The annual mean levels of $SO_2$, $NO_2$ and TSP in K area were 0.08lppm, O.03lppm and 173.4${\mu}g/m^3$, whereas those of E area were 0.044ppm, 0.02lppm and 146.0 ${\mu}g/m^3$ respectively. The mean levels of above three air pollutants between two areas showed difference about 1.2 times-1.8 times by air pollutant. 2. The monthly out-patient incidence rates of chronic obstructive pulmonary diseases, chronic bronchitis and asthma in K area were higher when compared with those of E area. The monthly out-patient incidence rates of above three chronic respiratory disease of two areas studied showed statistically significant difference about 1.3 times, 2.7 times, 1.4 times respectively. No difference were, however, shown in acute respiratory infections. 3. Highest incidence rates of out-patients could be observed among the group of children less than 10 years old, while adult out-patient incidence rates increased as age increased. 4. The relation between air pollution and chronic respiratory disease was obvious especially, the strongly significant correlation was observed between $NO_2$ and chronic bronchitis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.4
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• pp.587-593
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• 1994

A nutrition survey of 152 children , in the kindergarten attached to a proivate elimentary school of Pusan, was undertaken between Dec. 1 and Dec.14, 1993, to investigate dietary intake and nutrition status. The results are summarized as follows. 1) Compared with the Korean child development standard, their development conditions showed 113.1% , 102.2% , 103.3%, 101.75 in weight, height, head and chest, respectively. 2) By the standard of WLI(Weight Length Index) , proper to the children between age 4 and 6 , there proved to be 25% overweight and 4% obesity, 25% overweight and 19% obesity , 28 overweight and 26% obesity in 4-year-old, 5 year-old, and 6 -year-old children, respectively. 3) The children between age 4 and 6 averaged 37.6% in hematocrit and 12.4-12.8 5 in hemoglobin. these values were higher than those of the Korea child development standard. but the numbers of erythocyte, leucocyte and platelets were normal . Only a single child was considered suffering from aenmia . The 8% of them were over 200mg/이 in cholesterol, dangerously approaching the atherosclerosis. The 31% averaged 120mg/이 in triglyceride . And the 6% proved 100mg/이 in blood glucose when hung교. So it came out that not a few children had some factors dangers to diabetes, atherosclerosis and heart diseases : complications arising from obesity. 4) The intake of nutrients , except the 4-year-old children , ranged 108.4% to 2665 from the recommended value. The rates of carbohydrate, fat and protein to be much correlation among total intake of nutrients, development , results of blood test and WLI. The degree of obesity was proportionate to the intake of nutrients.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.29 no.1
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• pp.1-10
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• 1993

In order to investigate the environmental properties of set net grounds located in the coastal waters of Yeosu, oceanographic observations on the fishing grounds were carried out by the training ship of Yeosu Fisheries University from Jun. 1988 to Dec. 1990. The resultes obtained are summarized as follows; 1) The water mass in the fishing grounds were divided into the inner water (29.50-31.00$\textperthousand$), the mixed water (31.10-32.70$\textperthousand$) and the offshore water (32.70-34.30$\textperthousand$) according to the distribution of salinity from T-S diagram plotted all salinity data observed from Jun. 1988 to Dec. 1990. In spring the mixing water prevailed and in summer the inner and mixing water. But in autumn and winter the mixing and offshore waters prevailed. 2) The inner water which was formed by land water from the river of Somjin and the precipitation in the Yeosu district flowed southerly along the coast of Dolsando and spread south-easterly in the vicinity of Kumodo. The inner water and offshore water which supplied from the vicinity of Sorido and Yokchido formed the thermal front and halofront. 3) As the mixing water flowing from the western sea of Cheju to the southern coast of korea was low in temperature, the water mass of low temperature which appeared at the offshore bottom of Sorido in summer was considered not to be the Tsushima warm current. 4) As vertical mixing was made frequently in spring, autumn and winter, the differences in temperature and salinity between surface and bottom was respectively small. In summer, however, the mixing was not made because of the inner water expanded offshore through the space between surface and 10m layer and so a thermocline of $2.0^{\circ}C$/10m and halocline of 4.0$\textperthousand$/10m respectively in vertical gradient was formed. 5) In the vicinity of Dolsando and Kum a water low in salinity prevailed, but in the vicinity of Namhaedo and YoKchido the reverse took place. The inner and mixing waters formed at these arease was limited to the observation area not to spread widely.

• Journal of the Korea Fashion and Costume Design Association
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• v.14 no.3
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• pp.111-122
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• 2012

This study analyzed the differences in value perception and purchasing intention for natural cosmetics by LOHAS class and investigated what influences people's value perception for natural cosmetics had on their purchasing intention. Total 450 questionnaires were distributed to adults of over 20s to 50s for the period from Dec. 1, 2011 to Dec. 14 and 410 questionnaires were used as analysis data. As for collected data, the statistical package SPSS 18.0 Version was used for factor analysis, frequency analysis, reliability test, one-way ANOVA, Chi-Square test, Scheffe-test, correlations analysis and multiple regression analysis. LOHAS class was divided into three groups (higher, middle and lower) based on LOHAS index. Through factor analysis, the value perception for natural cosmetics were divided into three factors (social value, emotional and functional value perception). The results of this study were obtained as below. First, in case of the value perception for natural cosmetics by LOHAS class, it was demonstrated that the higher LOHAS classes they were, the higher value perception for natural cosmetics (social, emotional and functional value perception) they had. Second, in case of the effects of the value perception for natural cosmetics by LOHAS class on their purchasing intention (intention to use and recommendation of usage), it was found that their value perception influenced their purchasing intention. Social value perception and functional value perception, especially social value perception largely affected the purchasing intention of all LOHAS classes, while emotional value perception didn't affected the purchasing intention.