• Journal of Life Science
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• v.12 no.4
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• pp.433-441
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• 2002

There has been an increasing public concern about environmental safety and human health of field crops while customer consumes more and more field crops, to which overdose and residual chemicals were applied. As a solution for the problems, construction of sustainable agroecosystem is spreading out to pursuit the economic value of agricultural management as well as to meet environment concern. Public has extended their understanding on the preservation of environment and safeness of agricultural products, and governmental policy toward sustainable agriculture drives rapid increase of the production of sustainable agricultural products. Under this circumstances, it is time to encourage more consumption and to activate market system for the sustainable agricultural products. This study was initiated to diagnose the problems and future direction of domestic sustainable agriculture by analyzing the overall opinions of consumer on the sustainable agriculture. The results are as follows: The pursuit of low input management is a prerequisite to creat high valued agricultural products, and serious consideration should be taken to produce clean crops using natural products. Consummers are willing to pay 10∼50% more prices if the products get certified by official eco-label programs. It is believed that practice of sustainable agriculture using biopesticide and natural pesticide would accelerate the rapid extension of this pro-environmental agricultural management. To activate production and consumption of sustainable agricultural products correct informations on safety should be addressed to customer, and confidence has to be brought about from customer. This could be done by obtaining various and efficient distribution route, product competency for quality, upgraded sales strategy, maximum utilization of certificate system, and practice of recall system, so on.

• Journal of Korean Public Health Nursing
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• v.13 no.2
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• pp.143-160
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• 1999

The purpose of this descriptive survey study was to examine the following items. 1) Score distribution of life satisfaction. powerlessness. perceived health status and self-esteem 2) Demographic characteristics and the affection of socioeconomic characterictics to life satisfaction. powerlessness. perceived health status and self-esteem 3) Correlationship between life satisfaction. powerlessness. perceived health status and self-esteem 4) Determining the factors affecting life satisfaction The subjects were 167 urban elderly people. Data were collected from May to July in 1998 using the questionaires. The data were analyzed by mean. ANOVA. Pearson correlation coefficient and stepwise multiple regression with SPSS win 7.5 program. The results were as follows : 1) The degree of life satisfaction and powerlessness were relatively low with the mean score of 42.4 and 39.79 respectively. and perceived health status and self-esteem were relatively high with the mean score of 3.15 out of 5 and 27.3 respectively. 2) There were no significant differences between demographic characteristics and life satisfaction. Education(F=2.91. p=0.02), previous employment(F=2.23. p=0.03) and marital status(F=3.85. p=0.04) showed significant differences in the relationship between demographic characteristics and powerlessness. Sex(F=6.40. p=0.0l). education(F=3.30. p=0.0l). marital status(F=7.13. p=0.008) and kinds of living togather(F=3.69. p=0.003) showed significant differences in the relationship between demographic characteristics and perceived health status. There were no significant differences between demographic characeristics and self-esteem. 3) Monthly allowance(F=3.68. p=0.007). participation in social activity(F=5.90. p=0.000) and number of social activities(F=5.27. p=0.000) showed significant differences in the relationship between socioeconomic characteristics and life satisfaction. Monthly allowance(F=3.13. p=0.01) and number of social activities(F=2.7. p=0.02) showed significant differences in the relationship between socioeconomic characteristics and powerlessness. There were no significant differences between socioeconomic characteristics and perceived health status. Montly allowance(F=4.82. p=0.001). particpation in social activity(F=2.90. p=0.02) and number of social activities(F=3.79. p=0.003) showed significant differences m the relationship between socioeconomic characteristics and self-esteem. 4) Powerlessness showed negative correltionship with perceived health staus(r=-0.295. p<0.001). self-esteem(r=-0.463. p<0.001) and life satisfaction(r=-0.514. p<0.001). Perceived health status showed positive correltionship with self-esteem(r=0.312. p<0.001) and life satisfaction (r=0.377. p<0.001). Self-esteem showed positive correlationship with life satisfaction(r=0.652. p(<0.001). 5) The predicting variances for life satisfaction m elderly people were self-esteem. powerlessness. participation in social activity and perceived health status. The most influencing factor among the variances was the self-esteem$(42.5\%)$ and powerlessness was the second. Both of self-esteem and powerlessness accounted for $48.2\%$ in life satisfaction. The addition of participation of social activity and perceived health status accounted for $52.9\%$ in life satisfaction.

• Journal of Energy Engineering
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• v.17 no.1
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• pp.15-22
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• 2008

This study was carried out to investigate physical and chemical characteristics of the distillates and residue of Athabasca oilsand bitumen obtained from Canada, using a vacuum distillation unit. The distillates and residue produced from the vacuum distillation were characterized through atomic analysis, SARA analysis, and measurement of boiling point distribution, molecular weight, and API gravity. The vacuum distillation equipment consisted of a 6-litter volume vessel, a glass-packed column, a condenser, a reflux device, a flask fer collecting distillates, and a temperature controller. The cutting of distillates was performed with four steps under the condition of full vacuum and maximum temperature of $320^{\circ}C$. The results showed that the sulfur amount and average molecular weight of the distillates were significantly reduced compared to those of oilsand bitumen. As the cutting temperature increased, the hydrogen amount decreased but the sulfur amount and average molecular weight increased in the distillates.

• Archives of design research
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• v.11 no.2
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• pp.203-213
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• 1998

The forthcoming twenty-first century is at the mercy of information and culture. A quality of humanlife is under the control of a cultural level. A nation's creative culture and a cultural level represent all things about the nation; and a national image, as a whole result of culture, is enormously influential. This new era of culturalism gives us a significant responsibility for getting ready for the late industrial society by practically harmonizing rationality of modem culture with conception of traditional culture. Industrializing culture and culturalizing industry will be the most important strategy for existence in these days of borderless international competitiveness. Cultural products which is containing a nation's own culture can not only enhance the national image, but also become high value-added industry. While general products are developed for the purpose of convenient and practical use, cultural products are created with the intention of informing international society about a nation or a region. In order to confront with a global market system and a change of cultural environment, it is necessary to create a proper design with cultural inheritance for modem likes and senses, to produce the design on a commercial scale, and to strengthen its competitiveness on international markets. In order that a commodity is born, distributed throughout markets, and delivered to a final consumer, it is essential to understand complicated process such as development, distribution and marketing of products and to systematize each part. Although we should not neglect any part, a political and systemical plan or a distributional and marketing idea will be beside the point in this article. This article presents importance of traditional patterns as a Korean cultural image, and it shows the process of designing and developing products in order for traditional patterns to be utilized for products effectively. I expect that concrete activation and systematization for those works can be carried out successively.

• Communications of Mathematical Education
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• v.33 no.4
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• pp.471-488
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• 2019

This paper aims to examine how mathematical history is used in $ textbooks according to the 2015-Revised Curriculum. We analyze the distribution and characteristics of making use of the mathematical history in the nine textbooks, using the framework suggested by Jankvist (2009) on the whys and hows of using historical tasks. First, the tasks related to mathematical history in the textbooks are mostly used as an affective tool, while few tasks are used as a cognitive tool. Second, most of the historical tasks of the type of an affective tool are introducing the anecdotes of mathematicians or in the history of mathematics, and only one case is trying to show human nature of mathematics by illuminating the difficulties mathematicians were faced with. Third, all the mathematical history tasks used as affective tools and goals are illumination materials, while only two out of the ten tasks in the category of a cognitive tool are illumination materials, yet eight others are modular ones. Considering the importance and value of using mathematical history in the math education, this paper recommends that more modular materials on mathematical history tasks in the category of cognitive tools and goals should be developed and their deployment in the textbooks or courses should be promoted. $

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.1
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• pp.31-37
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• 1993

To analyze and classify the varietal variation of alkali digestibility in detail, which is closely connected with the gelatinization temperature and physical characteristics of cooked rice, the patterns of alkali decomposition changed along the alkali concentration were investigated for thirty three Korean leading rice cultivars and new breeding lines(japonica : 25, Tongil-type:8) including five glutinous rice. Principal component analysis was used to condense the information and to classify rice materials according to decomposed reaction pattern at several levels of potassium hydroxide(KOH) concentration. Thirty three rice varieties were classified largely into four groups by the distribution on the plane of upper two principal component scores which contained above 92% of total informations. Group I was consisted of one variety, Dobongbyeo, which owned almost same strong resistance to alkali digestion at the range of 0.8% to 1.6% KOH solutions. Group II included three japonica and Tongil-type glutinous rice varieties, which revealed medium alkali digestion value(ADV) at 1.4% KOH solution and intermediate change in ADV from 0.8% to 1.6% KOH solutions. Most of Tongil-type and early-maturity japonica rice, which exhibited medium-high ADV at 1.4% of KOH concentration and large ADV difference between low and high alkali solutions, were contained in Group III. Group N included most of medium or medium-late-maturity japonica, which showed high ADV at 1.4% KOH and medium or intermediate-high ADV change between low and high alkali solutions. The 1st principal component indicated the average index of ADV through 0.8-1.6% KOH solutions and the 2nd principal component pointed out the factor related with ADV difference between low and high alkali solutions or regression coefficients of ADV change along with the KOH concentrations.

• Asia pacific journal of information systems
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• v.17 no.4
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• pp.97-112
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• 2007

Most traditional newspaper publishers provide online editions to counter the competition of online news providers. However, the relationship between the online and print editions of the same newspaper has not been clearly defined. Some see the online newspaper as a substitute, while others consider it a complement. A 2002 NAA online newspaper consumer survey indicated that one-third of its respondents said they were now using the print newspaper less. Others have argued that the online edition will not wipe out print consumption, and may even complement it. While the print edition offers particular advantages such as portability, less eye strain, and the tactile experience of a printed page, the online edition also offers specific advantages such as access to breaking news, continually updated information, access to old archives, etc. All these factors would tend to lower the degree of interchangeability between the products. However, recent empirical studies show that the online edition is a substitute for rather than a complement of the print edition. Still, to some print readers, the online edition provides additional value. In this paper, by capturing the two different aspects of online editions the substitute aspect and the additional value added aspect as well as other available online alternatives, we develop an analytical model to derive the optimal production and distribution strategies of both online and print editions. Confronting the "free versus fee" issue, we show that it is optimal to provide an online version of the print newspaper for free to non-print subscribers. However, the amount of free news content that the publishers need to put on the Web depends on the available alternatives on the online market. The "fee" and "free" options both have merits and demerits as well. If the publisher charges for the online version of the print newspaper, she can generate revenue from the fee charged to online readers. However, doing so will limit the size of the online audience and further reduce online advertising revenue. At the same time, by providing a high-quality online version and charging for it, the price of the print newspaper must stay low in order to lure high valued readers. On the contrary, if the publisher provides an online version of the print newspaper for free, she can obtain a larger audience for the online version. At the same time, by providing a low-quality online newspaper, the publisher can increase the print newspaper price to get more revenue from high valued offline readers, although no revenue is incoming from online version readers. Through systematic measuring of all the pros and cons, our analysis shows that the optimal option is not "fee" but "free."

• Journal of the Korean earth science society
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• v.35 no.1
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• pp.29-40
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• 2014

A DC resistivity survey was performed to detect anomalies beneath concrete pavement. A set of high conductive media and planar electrodes were used to lessen the effect's a high contact resistance of concrete. Results of the resistivity survey were analyzed and compared with those of other geophysical surveys such as Ground Penetration Radar (GPR), Impulse Response (IR), and Multi-channel Analysis of Surface Waves (MASW), which were carried out in the same location. The results of resistivity survey showed a high resistive distribution in the section of sink and pavement where a pattern of reinforcement was observed through the GPR survey. Also, a comparison of results between the IR and resistivity surveys indicated that the high resistivity was produced by the high dynamic stiffness in the reinforced section. The co-Kriging of both the results of DC resistivity and MASW surveys at the same location showed that an integrated geostatistical analysis is able to give more accurate description on the anomalous subsurface region than can a separate analysis of each geophysical approach. This study suggests that the integrated geostatistical approaches were used for a decision-making process based on the geophysical surveys.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.8-13
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• 2018

Nitrogen oxides (NOx) have recently been very influential in the generation of ultrafine dust, which is of great social interest in terms of improving the atmospheric environment. Nitrogen oxides are generated mainly by the reaction of nitrogen and oxygen in air in a combustion gas atmosphere of high temperature in a combustion apparatus such as thermal power generation. Recently, research has been conducted on the combustion that recirculates the exhaust gas to the cylindrical burner by using a piping using a Coanda nozzle. In this study, three types of burners were carried out through computational fluid analysis. Case 1 burner with the outlet of the combustion gas to the right, Case 2 burner with both sides as gas exit, Case 3 burner with left side gas exit. The pressure, flow, temperature, combustion reaction rate and distribution characteristics of nitrogen oxides were compared and analyzed. The combustion reaction occurred in Case 1 and Case 2 burner in the right direction with combustion gas recirculation inlet and Case 3 burner in the vicinity of mixed gas inlet. The temperature at the outlet was about $100^{\circ}C$ lower than that of the other burners as the Case 2 burner was exhausted to both sides. The NOx concentration of Case 1 burner at the exit was about 20 times larger than that of the other burners. From the present study, it could be seen that it is effective for the NOx reduction to exhaust the exhaust gas to both side gas exits or to exhaust the exhaust gas to the opposite direction of inlet of recirculation gas.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.262-272
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• 2005

This study was undertaken to obtain design concentrations for the natural system treating stream water flowing into estuarine lake(Sapgyo). This lake has three major, so called, national-class streams: one is Gokgyo flowing through two medium-size municipal areas and the others are Muhan and Sapgyo placed in mostly rural area nested with some small towns. The results of three year's investigation showed big changes in water quality during the period between dry and wet seasons. Nitrogen concentration usually decreases as the flow rate increases. The change of phosphorus concentration in Gokgyo was the same pattern as nitrogen, but in other two streams it was inversely related with flow rates. This is probably due to the chemical property of the particles washed out from the different stream basins during wet season. It was found that about 40 to 60% of the total nitrogen are in soluble form and on average, 35% of the total phosphorus consists of dissolved-P. Representative concentration of these streams has to be separately determined based on dry and wet season. TDS and SS could be indicating parameters useful to depict and characterize a change of water quality with respect to flow rate because their measurement is easy and also includes a small analytical error. TDS values measured during dry season are related with high nitrogen concentration while during wet season, SS values effectively reflect a high concentration of phosphorus. For design purpose, cumulative concentration distribution graph presented in this paper can be directly or indirectly applied to other streams through a brief comparative and verificative study.