• 한국해양학회지
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• v.18 no.1
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• pp.55-63
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• 1983

The study on the periodic and correlation analysis between water temperature and air temperature has beenconducted by oceanographic data obtained from 1923 to 1979 (For 16-51 years) in 6 ststions in the Korean Waters. The periodic and correlation analyses has been examined by method of he Schuster's and the quadratic formula of least squares method, respectively. The results pbtained from the study are as follows; 1. Periodic analysis 1) The yearly difference between max. and mini. fo surface water temperature was 12.77-17.99$^{\circ}C$ (computed value : 11.67-16.64$^{\circ}C$) in offshore waters, and was 15.72-26.33$^{\circ}C$ (computed value : 15.13-25.29$^{\circ}C$) in inshore waters, and that of air temperature was 21.71-28.60$^{\circ}C$ (computed value : 10.50-27.22$^{\circ}C$). 2) The yearly mean of water temperature by station was 11.25-18.78$^{\circ}C$, and that of air temperature was 11.39-16.16$^{\circ}C$. 3) The annual compnent amplitrde of water temperature was 5.72-12.54$^{\circ}C$, and that of air temperature was 10.04-13.49$^{\circ}C$. 4) The semi-annual component amplitude of water temperature was 0.83-1.30$^{\circ}C$, and that of air temperature was 0.72-1.26$^{\circ}C$. 5) The annual component phase of water temperature was 215-228$^{\circ}C$ (max. temperature shall be in the first and in the middle ten days of August) in inshore waters and 138-244$^{\circ}C$ (max. temperature shall be in the first and in the middle ten days of August) in offshore waters, and that of air temperarture was 212-221$^{\circ}C$ (max. temperature shall be in the first and in the middle ten days of July and in the first tin days of August). 6) The semi-annual component phase of water temperature was 87-110$^{\circ}C$ in offshore waters, and 167-212$^{\circ}C$ in inshore waters, and that of air temperature was 156-189$^{\circ}C$. 2. Correlation analyses of water temperature and air temperature before one month. 1) When the water temperature is in rising time, the quadratic constant of correlation formual was the gradual inreasing type ( constant; 0.010-0.026) in offshore waters, and the gradual decreasing or proportional type (constant; -0.020-0.001) in inshore waters. 2) when the water temperature is in descending time, the quadratic constant of correlation formula was the gradual increasing type (constant: 0.012-0.021) 3) the determination coefficient was 0.964-0.992 at rising time and 0.982-0.999 at descending time of water temperature.

• Asia pacific journal of information systems
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• v.17 no.2
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• pp.97-122
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• 2007

Conventional networking and telecommunications infrastructure characterized by wires, fixed location, and inflexibility is giving way to mobile technologies. Numerous research reports point to the ultimate domination of wireless communication. With the increasing prevalence of advanced cell-phones, various mobile data services (hereafter MDS) are gaining popularity. Although cellular networks were originally introduced for voice communications, statistics indicate that data services are replacing the matured voice service as the growth engine for telecom service providers. For example, SK Telecom, the Korea's largest mobile service provider, reported that 25.6% of revenue and 28.5% of profit came from MDS in 2006 and the share is growing. Statistics also indicate that, in 2006, the average revenue per user (ARPU) for voice didn't change but MDS grew seven percents from the previous year, further highlighting its growth potential. MDS is defined "as an assortment of digital data services that can be accessed using a mobile device over a wide geographic area." A variety of MDS have been deployed, with a few reaching the status of killer applications. Many of them need to access the Internet through the cellular-phone infrastructure. In the past, when the cellular network didn't have acceptable bandwidth for data services, SMS (short messaging service) dominated MDS. Now, Internet-ready, next-generation cell-phones are driving rich digital data services into the fabric of everyday life, These include news on various topics, Internet search, mapping and location-based information, mobile banking and gaming, downloading (i.e., screen savers), multimedia streaming, and various communication services (i.e., email, short messaging, messenger, and chaffing). The huge economic stake MDS has on its stakeholders warrants focused research to understand associated dynamics behind its adoption. Lyytinen and Yoo(2002) pointed out the limitation of traditional adoption models in explaining the rapid diffusion of innovations such as P2P or mobile services. Also, despite the increasing popularity of MDS, unexpected drop in its usage is observed among some people. Intrigued by these observations, an exploratory study was conducted to examine decision factors of MDS usage. Data analysis revealed that the increase and decrease of MDS use was influenced by different forces. The findings of the exploratory study triggered our confirmatory research effort to validate the uni-directionality of studied factors in affecting MDS usage. This differs from extant studies of IS/IT adoption that are largely grounded on the assumption of bi-directionality of explanatory variables in determining the level of dependent variables (i.e., user satisfaction, service usage). The research goal is, therefore, to examine if increase and decrease in the usage of MDS are explained by two separate groups of variables pertaining to information quality and system quality. For this, we investigate following research questions: (1) Does the information quality of MDS increase service usage?; (2) Does the system quality of MDS decrease service usage?; and (3) Does user motivation for subscribing MDS moderate the effect information and system quality have on service usage? The research questions and subsequent analysis are grounded on the two factor theory pioneered by Hertzberg et al(1959). To answer the research questions, in the first, an exploratory study based on 378 survey responses was conducted to learn about important decision factors of MDS usage. It revealed discrepancy between the influencing forces of usage increase and those of usage decrease. Based on the findings from the exploratory study and the two-factor theory, we postulated information quality as the motivator and system quality as the de-motivator (or hygiene) of MDS. Then, a confirmative study was undertaken on their respective role in encouraging and discouraging the usage of mobile data service.

• Journal of Chest Surgery
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• v.40 no.3 s.272
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• pp.159-167
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• 2007

Background: Vocabularies originating from Chinese characters constitute an important common factor in the medical terminologies used 3 eastern Asian countries; Korea, China and Japan. This study was performed to comparatively analyze the medical terminologies of these 3 countries in the field of cardiopulmonary bypass (CPB) and; thereby, facilitate further understanding among the 3 medical societies. Material and Method: A total of 129 English terms (core 85 and related 44) in the field of CPB were selected and translated into each country's official terminology, with help from Seoul National University Hospital (Korea), Tokyo Michi Memorial Hospital(Japan), and Yanbian Welfare Hospital and Harbin Children Hospital (China). Dictionaries and CPB textbooks were also cited. In addition to the official terminology used in each country, the frequency of use of English terms in a clinical setting was also analyzed. Result and Conclusion: Among the 129 terms, 28 (21.7%) were identical between the 3 countries, as based on the Chinese characters. 86 terms were identical between only two countries, mostly between Korea and Japan. As a result, the identity rate in CPB terminology between Korea and Japan was 86.8%; whereas, between Korea and China and between Japan and China the rates were both 24.8%. The frequency of use of English terms in clinical practices was much higher in Korea and Japan than in China. Despite some inherent limitations involved in the analysis, this study can be a meaningful foundation in facilitating mutual understanding between the medical societies of these 3 eastern Asian countries.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1897-1904
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• 2010

The administration data of the national health insurance and health insurance bills were utilized in this study. The data of 432,915 patients who were at the age of 30 and up and used the out-patient departments of every medical institution located in some regions involving two southern and northern provinces once or more during a 184-day period from July to December. As a result of analyzing their prescription compliance and factors affecting it, the following findings were given: The average rate of the prescription compliance of the patients stood at 61.5 percent. It denoted that they were prescribed to take medicine for approximately 113 days during the six-month(184 days) period of time, and the rate of the patients who complied with the prescriptions just stood at 13.0 percent. They used out-patient department for 4.3 days on the average due to hypertension and they visited 1.1 medical institutions on the average. 94.9 percent just used a medical institution. The largest group (11.6%) suffered from diabetes as co-morbidity, and 23.3 percent of the hypertensives had co-morbidity. Concerning the relationship between their characteristics and prescription compliance, those who were male, who were beneficiaries of the national health insurance, who mainly used general hospitals and who suffered from co-morbidity complied better with the prescription they got. Their prescription compliance got better at the age of 65 to 74 and got worse afterwards. As for factors affecting their prescription compliance, the patients who were male, who were aged between 55 and 64 and who were beneficiaries of the national health insurance, who mainly used specialized general hospitals, general hospitals and public health centers and who had heart diseases and diabetes as co-morbidity complied better with the prescriptions. The above-mentioned findings of the study suggested that it's needed to make a factor analysis of the poor prescription compliance of patients from diverse angles, and that existing hypertension care plans should carefully be reviewed to improve the prescription compliance of patients and to find a feasible alternative. As hypertensives are easily likely to develop co-morbidity like diabetes, systematic health education should be provided for them to get into the right life habits such as taking low-salt meals or quitting smoking. In addition, the development of health care programs is required.

• Journal of Elementary Mathematics Education in Korea
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• v.19 no.4
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• pp.501-525
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• 2015

This study analyzes arithmetic word problem of multiplication and division in the mathematics textbooks and workbooks of 3rd grade in elementary school according to 2009 revised curriculum. And we analyzes type of the problem solving ability which 4th graders prefer in the course of arithmetic word problem solving and the problem solving ability as per the type in order to seek efficient teaching methods on arithmetic word problem solving of students. First, in the mathematics textbook and workbook of 3rd grade, arithmetic word problem of multiplication and division suggested various things such as thought opening, activities, finish, and let's check. As per the semantic element, multiplication was classified into 5 types of cumulated addition of same number, rate, comparison, arrayal and combination while division was classified into 2 types of division into equal parts and division by equal part. According to result of analysis, the type of cumulated addition of same number was the most one for multiplication while 2 types of division into equal parts and division by equal part were evenly spread in division. Second, according to 1st test result of arithmetic word problem solving ability in the element of arithmetic operation meaning, 4th grade showed type of cumulated addition of same number as the highest correct answer ratio for multiplication. As for division, 4th grade showed 90% correct answer ratio in 4 questionnaires out of 5 questionnaires. And 2nd test showed arithmetic word problem solving ability in the element of arithmetic operation construction, as for multiplication and division, correct answer ratio was higher in the case that 4th grade students did not know the result than the case they did not know changed amount or initial amount. This was because the case of asking the result was suggested in the mathematics textbook and workbook and therefore, it was difficult for students to understand such questions as changed amount or initial amount which they did not see frequently. Therefore, it is required for students to experience more varied types of problems so that they can more easily recognize problems seen from a textbook and then, improve their understanding of problems and problem solving ability.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.1
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• pp.1-12
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• 2018

This study sought to analyze changes in the vegetation structure and species diversity indices in the Abies koreana forest in the Yeongsil area of Hallasan Mountain and establish basic data for Long-Term Ecological Research (LTER). The results show that the number of woody plants per 1ha has increased by 804 (45.1%) from 1,781 to 2,585 individual plants, whereas the number of live A. koreana did not change much with 796 individual plants. The number of dead tree plants, however, jumped by 807 (82.2%) from 982 to 1,789 plants. With other tree species, the number of live individual plants increased by 807 (82.2%) from 982 to 1,789 plants, whereas the number of dead plants increased by 31 from 10 to 41 individual plants. Results of the average importance index analysis show that the number of A. koreana decreased, while the number of Weigela subsessilis, Rhododendron yedoense for. poukhanense, and Magnolia sieboldii increased. The species diversity index increased by 6.7% as per the maximum level in the upper layer and by 7.2% in the lower layer, respectively. Results of the stem morphology analysis show that the number of AS type was highest with 700 individual plants among A. koreana, while their distribution by type shifted from AS>AL>DS>DB to AS>DS>AL>DB. As for other species, the AS type was most abundant with 1,580 individual plants, while their distribution by type shifted from AL>AS>AF>AB to AS>AL>AB>AD. The number of newly sprouted tree plants has increased from 420 in 2014 to 453 in 2016. Of the individual plants that were alive in 2014, 23 were found dead and 33 individual plants younger than 3 years old have been newly added to the group. The number of deaths after 2014 was highest among the 2 years olds, whereas the number of 2 years olds that sprouted in 2014 was highest among the newly sprouted tree plant group. In the A. koreana forest in Yeongsil, the density of other species was rising rapidly with the exception of the dead and live A. koreana. The occurrence of new tree plants is decreasing rapidly, thereby confirming the rapid change in the area's vegetation structure. Therefore, there is a need for continuous long-term ecological research to monitor vegetation change. It can also be used as a basic data for efficient restoration research.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.305-310
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• 2001

The purpose of this study is to calculate delay damages for contractors. The study has been performed by investigation of delay cost occurrence status and the analysis of subway construction cases. The results of this study are as follows: 1. Delay cost( 1day) equivalent to $0.005\%$ of total construction cost by analysis case studies. 2. Including bank interest, dealy cost is analysed as the following; $1.1\~9.2\%$ of total construction cost in part extension period, $3.3\~11.0\%$ of total construction cost in total extension period. 3. In comparison between liquidated damages and delay cost, liquidated damages account for average 20.1 times of delay costs. 4. Acceleration cost will be calculate on the basis of delay cost calculation method. In the result of this method, acceleration cost is equal to delay cost at least or must be large than delay cost

• KDI Journal of Economic Policy
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• v.31 no.1
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• pp.105-138
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• 2009

Although the decline in fertility rate is generally observed along the history of economic development throughout the world, the continuing decline hitting below the replacement level in Korea over the recent years gathered serious social concerns on the ground that it accelerates the process of population aging. The total fertility rate in Koreareached 2.08 in 1983, and gradually fell to the levels of 1.08 in 2005 and 1.26 in 2007. The policy debate over the role of the government has been focused mainly on the level of theoretical discussion without substantial basis on firm empirical evidence and the determinants of fertility. The objective of the paper is to empirically investigate the fertility effect of the female wage, which is understood as one of the most important determinants of fertility in Koreasince 1980 focusing on one aspect of fertility, namely birth spacing. Using the Korean National Fertility Survey conducted in 2006, I estimate a duration model of first and second births taking into account individual heterogeneity, which turned out to be an important factor to control for. Compared with previous studies in the literature on the Korean fertility, the study has an advantage of using the complete pregnancy history of women in a more representative sample. Unlike the previous studies, the analysis also deals with the endogeneity of marriage by treating a certain age, rather than age at marriage, as the time in which a woman becomes exposed to the risk of pregnancy. The study shares the common problem in the literature on birth spacing of lacking relevant wage information for respondents in a retrospective survey. I estimate the wage series as a function of the basic characteristics using the annual Wage Structure Survey from 1980 to 2005, which is considered as a nationally representative sample for wage information of employees. The results suggest that the increase in female wage by 10 percent leads to a decrease in second birth hazard by 0.56~0.92 percentage points and that the increase in spouse's wage by the equal amount is accompanied by the increase in second birth hazard by 0.36~1.13 percentage points. These estimates are more precisely estimated and of smaller magnitude than those presented by the previous studies. The results are robust to the different specifications of the wage equation. The simulation analysis based on the predicted values shows that about 17% of the change in the second birth hazard over the period 1980 to 2005 was due to the change in the female wage. Although there is some limitation in data, the results can be viewed as one estimate of the role of female wage on the recent fertility decline in Korea. The question raised by the paper is not a normative one of whether a government should promote childbearing but a positive one thatexplains fertility decline. Therefore, if there is a wide consensus on promoting childbearing, the finding suggests that the policies designed to reduce the opportunity cost of women in the labor market would be effective. The recent movement of implementing a wide range of family-friendly policies including child care support, maternity leave, parental leave and tax benefit in developed countries should be understood in this context.

• Radiation Oncology Journal
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• v.23 no.1
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• pp.51-60
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• 2005

Purpose : Selective inhibition of multiple molecular targets may improve the antitumor activity of radiation. Two specific inhibitors of selective cyclooxygenase-2 (COX-2) and epidermal growth factor receptor (EGFR) were combined with radiation on the HeLa cell line. To investigate cooperative mechanism with selective COX-2 inhibitor and EGFR blocker, in vitro experiments were done. Materials and Methods : Antitumor effect was obtained by growth inhibition and apoptosis analysis by annexin V-Flous method. Radiation modulation effects were determined by the clonogenic cell survival assay. Surviving fractions at 2 Gy ($SF_2$) and dose enhancement ratio at a surviving fraction of 0.25 were evaluated. To investigate the mechanism of the modulation of radiosensitivity, the cell cycle analyses were done by flow cytometry. The bcl-2 and bax expressions were analyzed by western blot. Results : A cooperative effect were observed on the apoptosis of the HeLa ceil line when combination of the two drugs, AG 1478 and NS 398 with radiation at the lowest doses, apoptosis of $22.70\%$ compare with combination of the one drug with radiation, apoptosis of $8.49\%$. In cell cycle analysis, accumulation of cell on $G_0/G_l$ phase and decrement of S phase fraction was observed from 24 hours to 72 hours after treatment with radiation, AG 1478 and NS 398. The combination of NS 398 and AG 1478 enhanced radiosensitivity on a concentration-dependent manner in HeLa cells with dose enhancement ratios of 3.00 and $SF_2$ of 0.12 but the combination of one drug with radiation was not enhanced radlosensitivity with dose enhancement ratios of 1.12 and SF2 of 0.68 (p=0.005). The expression levels of bcl-2 and bax were reduced when combined with AG 1478 and NS 398. Conclusion : Our results indicate that the selective COX-2 inhibitor and EGFR blocker combined with radiation have potential additive or cooperative effects on radiation treatment and may act through various mechanisms including direct inhibition of tumor cell proliferation, suppression of tumor cell cycle progression and inhibition of anti-apoptotic proteins.

• Applied Biological Chemistry
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• v.50 no.2
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• pp.95-100
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• 2007

The cellulase gene of Bacillus licheniformis K11 which has plant growth-promoting activity by auxin and antagonistic ability by siderophore was cloned in pUC18 using PCR employing heterologous primers. The 1.6kb PCR fragment contained the full sequence of the cellulase gene, denoted celW which has been reported to encode a 499 amino acid protein. Similarity search in protein data base revealed that the cellulase from B. licheniformis K11 was more than 97% identical in amino acid sequence to those of various Bacillus spp. The cellulase protein from B. licheniformis K11, overproduced in E. coli DH5${\alpha}$ by the lac promoter on the vector, had apparent molecular weight of 55 kDa upon CMC-SDS-PAGE analysis. The protein not only had enzymatic activity toward carboxymethyl-cellulose (CMC), but also was able to degrade insoluble cellulose, such as Avicel and filter paper (Whatman$^{\circledR}$ No. 1). In addition, the cellulase could degrade a fungal cell wall of Phytophthora capsici. Consequently B. licheniformis K11 was able to suppress the peperblight causing P. capsici by its cellulase. Biochemical analysis showed that the enzyme had a maximum activity at 60$^{\circ}C$ and pH 6.0. Also, the enzyme activity was activated by Co$^{2+}$ of Mn$^{2+}$ but inhibited by Fe$^{3+}$ or Hg$^{2+}$. Moreover, enzyme activity was not inhibited by SDS or sodium azide.