• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.11
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• pp.779-789
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• 2014

Cognitive radio (CR) technology based on geo-location database access approach and/or wideband spectrum sensing approach is absolutely vital in order to recognize available frequency bands in white spaces (WSs), and efficiently utilize shared spectrums. This paper presents a new structure for the TVWS database access protocol implementation based on Internet Engineering Task Force (IETF) Protocol to Access WS database (PAWS). A wideband compressive spectrum sensing (WCSS) scheme using a modulated wideband converter is also proposed for the TVWS utilization. The developed database access protocol technology which is adopted in both the TV band device (TVBD) and the TVWS database operates well in the TV frequency bands. The proposed WCSS shows a stable performance in false alarm probability irrespective of noise variance estimation error as well as provides signal detection probabilities greater than 95%. This paper also investigates Federal Communications Commision (FCC) regulatory requirements of TVWS database as well as European Telecommunications Standards Institute (ETSI) policy related to TVWS database. A standardized protocol to achieve interoperability among multiple TVBDs and TVWS databases, which is currently prepared in the IETF, is discussed.

• Research in Community and Public Health Nursing
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• v.10 no.1
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• pp.93-105
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• 1999

Recently, Korean health care industry managers are paying more attention to customer oriented service, the rationalization of business administration, and quality control of service to adjust their business to outer environment since IMF bailout program. They are focusing on the cost reduction through remodeling the size and structure of man power, viz. labor flexibility. Nurses are not free from this juncture and contingent nurses are increasing fast. This article intends to verify the actual condition of two types of contingent nurses -part-time nurses and internship nurses-and to compare their job satisfaction to provide basic resource for efficient management of nurse man power. The concrete goals of this article are; Firstly, to verify the actual condition of their employment. Secondly, to compare their job satisfaction. And Thirdly, to the relation between employment condition and job satisfaction. To accomplish these research goals, a statistical survey was executed, in which 384 questionnaires - 66 for manager nurses, 318 for contingent nurses-were given to nurses working at 66 general hospitals-which have at least 100 beds-in Seoul. Among them, 121 questionnaires-of 28 general hospitals-were returned. Then, the data coded and submitted to mean, standard deviation, T-test, variance analysis (ANOVA), correlation analysis, multiple regression analysis with SAS program. The research results of the contingent nurses are followings: 1. Two types of contingent nurses shows similar age spans: they are mostly 21 - 30 years old and unmarried. But internship nurses have high level of educational career. Part - time nurses spread at general beds, out -patient part, intensive care part, operation part, etc, but internship nurses work mostly at general beds. 2. Two groups shows difference in actual employment condition: average employment career of part -time nurses is 7.0 months but internship nurses' is 2.0 months: average duty-on days per month of part - time nurses are 23.7 days but internship nurses' are 24.8 days. But there are little difference in average working time per day: 7.7 hours for part -time nurses and 0 hours for internship nurses. 3. The average wage per month for part -time nurses is 836,026 won but for internship nurses is 557,428 won-66.7% of part-time nurses'. Both groups are enjoying little additional pay. 4. Both groups are getting job not so much through advertisement of newspaper or hospitals as through acquainted person or college. 5. Both groups show very high level of job satisfaction: 3.2195 for part -time nurses and 3.2881 for internship nurses. But they show very low satisfaction on payment level compared with other categories and two groups show meaningful difference(P<.0001). 6. The multiple regression test reveals the factors related with job satisfaction: wage level, working part(OR or ICU), age, job career, and motive of contingent job-taking('because I can take care of family duties at the same time') influence positively: motive of contingent job-taking('because I can work regularly without alternation') influences negatively.

• Archives of design research
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• v.15 no.4
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• pp.33-46
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• 2002

The present times is rapidly growing and changing. As both an industry and a social legislation are running after a generality, relatively the number of people who are out of it is gradually increasing. Those people are getting skeptical about their positions as well as their existences, so that a social deviant phenomenon has been continuously arising by themselves in public and private area. It is the Vandalism . People are often exposed to this Vandalism which is occurring around their life. Accordingly this study analyzed cause-and-effect Vandalism. As a means of impediment against the progressing Vandalism in design process, the study as been developed by approaching to an ergonomics design, a simple shape design (minimalism), a semantic design, a re-useful design. As a result, it comes to the fact that the Vandalism from the view of design is caused by a lack of ergonomics and user-interface, a failure of simple structure, a complication of excessive functions. Furthermore, it comes to the conclusion that industrial design is playing an important role in the contribution of social development, to create a design obstructing the vandalism will bring development of sound society.

• Journal of the Korean Society for information Management
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• v.33 no.1
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• pp.111-137
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• 2016

The roles of public libraries have been diverse not only provision of information but also provision of cultural programs. According to this trend, the spatial composition of public libraries have been also changed to reflect the diverse roles. This study is conducted to explore the spatial characteristics in public libraries with two objectives: 1) to suggest spatial types in public libraries based on their physical characteristics, and 2) to explore the relationships between the spatial types and users' perception. To accomplish these objectives, we adopted observation and questionnaire survey as research methods. Consequently, three spatial types of public libraries are identified based on an investigation of several public libraries: divided, partially integrated, and integrated. Then, several statistical analyses, including one-way analysis of variance (ANOVA), are conducted with the questionnaire survey data. The results from the statical analyses show that there are significant differences in users' perceptions and behaviors between the spatial types. That is, the spatial type influences user's perceptions. This study is meaningful in terms of its first attempt to explore the relationships between spatial factors in libraries and users' perceptions. Based on this, it is suggested that libraries should consider their spatial structures for developing user's positive perception on the libraries.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.503-512
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• 2017

The perceived stress of pregnant women is a potential contributor to adverse birth outcomes. Although the importance of the psychosocial well-being of pregnant women has been emphasized, there are fewreliable and valid instruments to measure the stress level of pregnant women in Korea. This study evaluated the psychometric properties of Ahn's pregnancy related stress scale (PSS) that was originally developed in 1984. Two hundred pregnant women completed the survey questionnaire, which was comprised of the PSS, depression scale, and demographic information. Principal component analysis and confirmatory factor analysis was used to test the construct validity. The concurrent validity was evaluated using the correlation with depression scores. Based on exploratory factor analysis and a consideration of conceptual meaning, a five-factor structure was extracted, explaining 57.25% of the variance: physical discomfort, fetus, parenting, spouse relationship, and housework. The goodness-of-fit indices showed an acceptable fit overall with the full model and acceptable internal consistency (Cronbach's alpha =.89). The concurrent validity was confirmed by a comparing with the depression score (r=.48, p <.001). The shortened PSS, as a valid and reliable scale, is recommended to be used to assess pregnancy-related stress and to develop stress managing interventions for pregnant women in clinical settings.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2707-2711
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• 2014

Introduction: Smoking prevalence among the medical students is high in China. Therefore, understanding the smoking motivations of medical students is crucial for smoking control, but currently there are no scales questionnaires customized for probing the smoking motivations of medical students. This aim of study was to test and modify a questionnaire for investigating smoking motivations among medical students. Methods: A cross-sectional survey was conducted among 1,125 medical students at Xuzhou Medical College in China in 2012.The model fit and validity was assessed by confirmatory factor analysis (CFA) and the reliability was tested by single-item reliability, composite reliability, and item-total correlation. Results: The prevalence of smoking was 9.84 % among study population. In the modified scales, the global fit indices identified a CFI value of 0.96, TLI was 0.96, and the RMSEA was 0.063. CFA supported the two dimensional structure of the instrument. The average variance extracted ranged from 0.45 to 0.62. All single-item reliability scores were greater than 0.20, and the composite reliability ranged from 0.74 to 0.91. Conclusion: Modified scales could be the preliminary instrument used in evaluating the smoking motivations of medical students. However, it should be further assessed using other forms and methods of validity and reliability, additional motivations of smoking, and the survey of other medical colleges in China.

• Korean Journal of Optics and Photonics
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• v.21 no.6
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• pp.247-253
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• 2010

A dual-layer light guide plate (DLGP) was designed and a simulation was done to optimize the structure of the light guide plates used at backlight units while maintaining the luminance, uniformity and viewing angle by reducing the optical sheet. The characteristic of DLGP with prism pattern with curvature on the top surface is simulated and the luminance and uniformity are obtained. In order to improve the uniformity, the V groove prism pattern on the bottom surface was turned by an angle of $90^{\circ}$. In particular, we used the pitch calculation program to select the value of the ratio (Max : Min) between the pitch at the extreme outside and the pitch at the middle, the number of V groove lines and the variance at the bottom pattern of DLGP. After that, the optimum distance between V grooves was determined. For optimizing the DLGP, we examined the uniformity again by changing the number of pattern grooves on the bottom surface of DLGP. As a result of the simulation, we find that the BLU with DLGP has a uniformity of 90.6% and viewing angle $145^{\circ}$.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.2
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• pp.227-238
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• 2006

Line density index(LDI) was developed to quantify a densely isothermal line rate as standard index in the ocean environment. Theoretical background on the LDI development process restricting index range 0 to 100 was described. And validation test was done for the LDI application condition that total line length is not greater than 1/10 of unit area. NOAA SST(Sea Surface Temperature) data were used for the experimental application of LDI in the South Sea of Korea. Using GIS, $0.1^{\circ}C$ isothermal lines were linearized as vector data form SST raster data, and unit area were built as polygon data. For the LDI calculation, spatial overlapping(line in polygon) was implemented. To analyze the effect of unit area size for the LDI distribution, two cases of unit area size were designed and descriptive statistics was calculated including performing normality test. The results showed no change of LDI's essential characteristics such as mean and normality except for the range of value, variance and standard deviation. Accordingly, it was found that complex structure of thermal front and even smaller scale of front width than unit area size could influence on the LDI distribution. Also, correlation analysis performed between LDI and difference of temperature(${\Delta}T^{\circ}C$), and horizontal thermal gradient(${\Delta}T^{\circ}C/km$) on the front was obtained from linear regression model. This obtained value was compared with the results from previous researches. Newly developed LDI can be used to compare the thermal front regions changing spatio-temporally in the ocean environment using absolute index value. It is considered to be significant to analyze the relationship between thermal front and marine environment or front and marine organisms in a quantitative approach described in this study.

• Journal of dental hygiene science
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• v.9 no.1
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• pp.53-59
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• 2009

Infection control is now recognized as an important quality indicator in dental health service setting. The purpose of this study was to develop and validate Dental Hygienist's Infection Control Practice Scale for quality management of dental health service in Korea. The data of 254 dental hygienists was subjected to exploratory factor analysis using SPSS 16.0 and confirmatory factor analysis using AMOS 16.0. The total items of preliminary scale were 21 items and 5 subscale. Principal component analysis was completed with Varimax rotation. The results show a change in factor structure from 5 factor solution to 4 factor solution. The confirmatory factor analysis confirmed the four subscales(Immunization and periodic tests, Clinical procedure, Handwashing, Personal protection) which have a total of 12 items. After the item deleted because factor loading was low, measured model was tested. The results of the measurement model indicated fit indices: $x^2$= 79.593(df = 38, 0 = 0.000), RMR = 0.045, GFI = 0.940, CFI = 0.904, AGFI = 0.896, NFI = 0.837, TLI = 0.861, RMSEA = 0.67. The squared correlation between four constructs were less than the average variance extracted(AVE) of four constructs. Multiple regression analysis was completed. Dependent variable was the perceived infection control practice by dental hygienist. Independent variables were four summated subscales(R = 0.552, $R^2$= 0.304, Adjusted $R^2$= 0.431, F = 25.813, p = 0.000). Unstandardized coefficients of three independent variables were statistically significant.

• Journal of Korean Society of Forest Science
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• v.107 no.2
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• pp.151-157
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• 2018

This study was to analyze the genetic diversity of Quercus gilva Blume growing in Jeju Island for developing a preservation strategy. We examined the genetic diversity and structure using 6 ISSR primers and investigated 67 polymorphic ISSR amplicons in 80 trees distributed among five populations. The average of proportion of polymorphic loci were 93%, the average level of Shannon's information index was 0.237, and Nei's genetic diversity was 0.156. According to the analysis of the molecular variance (AMOVA), $F_{st}$ was 0.169 indicating there was a genetic variation among five populations. 17% of the total variation was allocated among the five populations, while the other 83% of the total variation was in individual trees in each population. The result could be due to the uneven number of trees among the five populations. Based on these results, the preservation strategy could be developed, for examples, considering for designation as "forest genetic resources conservation area" about the habitat, monitoring continuously, fostering the growth of seedling, ex situ preservation of genetic resources, and comparing the differences of environmental and genetic characteristic with population in ex situ.