• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.592-597
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• 2020

Currently, river survey data is mainly performed by acquiring longitudinal and cross-sectional data of rivers using total stations or the GNSS(Global Navigation Satellite System). There is not much research that addresses the use of LiDAR(Light Detection and Ranging)systems for surveying rivers. This study evaluates the applicability of using LiDAR data for surveying rivers The Ministry of Land, Infrastructure and Transport recently launched a drone-based river fluctuation survey. Pilot survey projects were conducted in major rivers nationwide. Studies related to river surveying were performed using the ground LiDAR(Light Detection And Ranging)system.Accuracy was ensured by extracting the linearity of the object and comparing it with the total station survey performance. Data on trees and other features were extracted to generate three-dimensional geospatial information for the point-cloud data on the ground.Deviations were 0.008~0.048m. and compared with the results of surveying GNSS and the use of drone LiDAR data. Drone LiDAR provided accurate three-dimensional spatial information on the entire target area. It was able to reduce the shaded area caused by the lack of surveying results of the target area. Analyses such as those of area and slope of the target sites are possible. Uses of drones may therefore be anticipated for terrain analyses in the future.

• Journal of Korea Technology Innovation Society
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• v.20 no.1
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• pp.175-204
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• 2017

The existing innovation policies and strategies mainly focused on the influencing factors for improvement of innovation outcome. However, these strategies were not always successful in driving innovative activities that make technology innovation disseminated. In this regard, innovation ecosystems approach has recently been coming to the force to establish a successful innovation strategy. The innovation ecosystems concept describes that innovation processes are evolved through collaborative networks of economic actors. In an innovation ecosystem, different organizations collaborate for technology development and its use. They interact for value co-creation by sharing mutual resources. The organizational networks are re-organized by dynamic changes of actors' interactions, which drive innovation mechanism of the networks. Recent studies on innovation ecosystems mostly have paid attention on developing theoretical frameworks to describe dynamics of an innovation ecosystem. There have hardly been empirical tests on the theoretical ecosystem models. In this vein, we investigated dynamics of an innovation ecosystem by analyzing structural characteristics of a collaborative network among organizations which are involved in the use of innovative technologies. Particularly, we examined the longitudinal changes of the interaction patterns among the organizations. This test was performed by an analysis of structural equivalence on the network dataset transformed from the organizational interactions. This result provides a guideline for an organization in developing an innovation strategy under a systemic perspective.

• Korea journal of population studies
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• v.35 no.1
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• pp.211-238
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• 2012

Using data from Korean Longitudinal Study on Aging (KLoSA), this study examines how continuity and change of marital status is associated with health over time among older women, focusing on the moderating effects of age and parent-child relationships. KLoSA data set has two waves of interviews, and for this study, 2046 women aged 65 and over were selected. To analyze data, Structural Equation Modeling (SEM) was used. The major findings are as follows. First, there was no statistically significant difference in health between continuously married older women and continuously single older women. However, older women who had transition from being married to being single showed lower physical health than continuously married and continuously single older women. Second, there were statistically significant differences in the effect of marital status on mental health according to the age of older women. Older women who had transition from being married to being single showed lower mental health than continuously married elders when older women were younger. Third, contact with children moderated the effect of marital status on physical health. Older women who had transition from being married to being single showed lower physical health than continuously single and continuously married older women when older women had less contact with their children. The findings imply after the loss of marital role, older women's relationship with adult children plays a significant role in promoting health. In conclusion, the findings of this study show the different pathways through which marital status is associated with health for 3 different groups of older women, being continuously single, being continuously married, and making transition from being married to being single.

• Korea journal of population studies
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• v.33 no.1
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• pp.103-131
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• 2010

This study observes how the conjugal sharing of the roles such as breadwinning, housework/childcare, and leisure activities affects wives' marital satisfaction, and how the relationships among the considered variables are similar or different across age categories. Two dependent variables, the relationship satisfaction and the marital happiness, are measured and estimated as the concept of the marital satisfaction. Analysed is the Korean Longitudinal Survey of Women and Families 2008 collected by Korean Women's Development Institute. Among women in the ages of 30s-50s, full-time housewives with the breadwinning husbands feel happier with their marriage than the wives in dual career families, and those in dual career families are happier than the breadwinning women with the househusbands. Among the women in their 40s, the highest relationship satisfaction is reported by the those of the dual career families. Wives in their 30s prefer equal division of familywork in explaining the relationship satisfaction, while wives in the age of 40s and 50s show only the effect of reducing wives' portion. The co-spousal leisure activity is consistently significant in its positive relationship with the marital satisfaction across the age categories. There is a general tendency that the marital satisfaction is the highest in the youngest age bracket and the lowest in the oldest. For managing better marriages, individual efforts of both spouses as well as social support are required.

• Journal of Cadastre & Land InformatiX
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• v.47 no.1
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• pp.143-160
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• 2017

Since officially assessed land price system was introduced, it has functioned as the criterion for establishing and implementing real estate policies. However, there is a controversial issue about the adequacy of the officially assessed land price system. The problem is that it is difficult to establish a statistical model due to too many land characteristics. Also, local economy, macroeconomic environments and development plans are not reflected in the land price evaluation model. Considering longitudinal and cross-sectional variables, a two-way error component panel model was used in this study. This analysis model includes variables reflecting land characteristics, macroeconomic volatility, and development project. The Paju LCD Industrial Complex was selected as a analysis area and an empirical analysis was performed. According to the analysis, the number of significant land characteristic variables were 14(31%) under 5% significance level. Macroeconomic volatility has had an influence on the land price and year variable reflecting development project has consistently been significant since the industrial complex was designated. Therefore, this study suggests that the land price evaluation model should be improved by simplifying land characteristic variables and including macroeconomic and regional economic variables.

• Steel and Composite Structures
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• v.6 no.6
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• pp.459-477
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• 2006

A theoretical research project is undertaken to develop integrated analysis and design tools for long span composite beams in modern high-rise buildings, and it aims to develop non-linear finite element models for practical design of composite beams. As the first paper in the series, this paper presents the development study as well as the calibration exercise of the proposed finite element models for simply supported composite beams. Other practical issues such as continuous composite beams, the provision of web openings for passage of building services, the partial continuity offered by the connections to columns as well as the behaviour of both unprotected and protected composite beams under fires will be reported separately. In this paper, details of the finite elements and the material models for both steel and reinforced concrete are first described, and finite element studies of composite beams with full details of test data are then presented. It should be noted that in the proposed finite element models, both steel beams and concrete slabs are modelled with two dimensional plane stress elements whose widths are assigned to be equal to the widths of concrete flanges, and the flange widths and the web thicknesses of steel beams as appropriate. Moreover, each shear connector is modelled with one horizontal spring and one vertical spring to simulate its longitudinal shear and pull-out actions based on measured load-slippage curves of push-out tests of shear connectors. The numerical results are then carefully analyzed and compared with the corresponding test results in terms of load mid-span deflection curves as well as load end-slippage curves. Other deformation characteristics of the composite beams such as stress and strain distributions across the composite cross-sections as well as distributions of shear forces and slippages in shear connectors along the beam spans are also examined in details. It is shown that the numerical results of the composite beams compare well with the test data in terms of various load-deformation characteristics along the entire deformation ranges. Hence, the proposed analysis and design tools are considered to be simple and yet effective for composite beams with practical geometrical dimensions and arrangements. Structural engineers are strongly encouraged to employ the models in their practical work to exploit the full advantages offered by composite construction.

• The Journal of Korean Academic Society of Nursing Education
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• v.15 no.1
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• pp.32-43
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• 2009

Purpose: The purpose of this study was to identify the trend of nursing research by analyzing the doctoral dissertations in one college of nursing in Korea. Method: The areas of research, the methodological characteristics, and theories used in the research were explored in all doctoral dissertations (n=120) published from 1989 to 2006. Result: Mainly "Nursing" has been studied (44.9%) among four meta-paradigms of nursing science. The "client" domain (46.7%) and the "practice" domain (41.7%) were most frequently studied in type of nursing knowledge. The main purpose of the thesis was to develop nursing interventions and examine the effectiveness of the practice (40.8%) in quantitative research. Almost all (94.7%) of the qualitative dissertation studies were to explore phenomena in the nursing field. Almost half of the dissertations (43.9%) were an experimental design, 34.7% were a model construction, and 15.8% were a qualitative design. The majority of dissertations (83.3%) were to apply the specific theory and almost half (43.8%) studied borrowed theories from other fields. Conclusion: It is necessary to develop more rigorous and various research designs such a longitudinal design, or randomized controlled trial and this will lead to expanding the body of nursing knowledge.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.1
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• pp.19-28
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• 2010

This study was designed to investigate the effect of increased blood and tibia lead on the change of bone mineral density in retired male lead workers. One hundred nine retired male lead workers who worked in 4 different lead industries and 51 nonoccupationally lead exposed male subjects were recruited from March 2004 to October 2004. Bone mineral density(BMD) was measured by broadband ultrasound attenuation(BUA) at left calcaneous bone area with broadband ultrasound attenuation method of QUS-2(Metra Biosystems Inc, USA). Tibia bone lead was measured for skeletal bone lead with K-xray fluorescence(K-XRF) and blood lead was analyzed with flameless atomic spectrophotometer. Hemoglobin, hematocrit, serum calcium and iron were also analyzed. In addition, information for smoking and drinking status and basic personal data such as age and lead exposure were also collected using questionnaire inquiry. Blood lead was correlated with tibia lead (r=0.711) and these two variables were negatively correlated with BUA in bivariate analysis. BUA and tibia lead showed significant main effects on the change of blood lead after adjusting covariates. The effect modification by the level of BMD (low: lower than the median of BUA and high: higher than the median of BUA) was observed between the association of tibia lead and blood lead after adjustment of covariates. The subjects who had higher BMD seemed to have lower blood lead by the increase of tibia lead than those of lower BMD. In the multiple regression analysis of blood lead and tibia lead on BUA after adjustment of covariates, only blood lead showed statistically significant effect on BUA. This study confirmed that BMD and blood lead were significantly associated. To verify the causal association of BMD on blood lead and vice versa, further longitudinal studies are needed.

• Journal of the Korean Geographical Society
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• v.42 no.4
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• pp.506-525
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• 2007

Incision into bedrock channel is the primary control of landform evolution, but research into bedrock incision process stagnated for long time. Due to the scaling problem of the application of results from flume studies to bedrock channel, there is a strong need to simulate the bedrock incision process with more realistic models. As a part of investigation into controls of bedrock channel incision, three-dimensional changes of rock surface with abrasion was investigated with physical modelling. 18 rock plates were abraded with various sediment particle size and sediment load and abraded surfaces of the plates were scanned with high resolution 3-D scanner. To identify the spatial pattern of erosion of the rock plates, various methods were used. There was no synthetic or holistic method that showed all features of bedrock plate produced by abrasion, so each plate was analyzed using some available methods. Contour maps, shaded relief maps and profiles show that abrasion concentrated on the centre of plate (cross profile) and upstream and downstream edges (longitudinal profile) and eroded area extended inwards. It also found that the cracks and boundaries of forming materials easily eroded than other parts. Changing patterns of surface roughness were investigated with profiles, regression analysis and spectral analysis. Majority of plates showed decrease in small-scale roughness, but it depends on microstructures of the plates rather than general hardness or other factors. SEM inspection results supported this idea.

• Korean Journal of Biological Psychiatry
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• v.24 no.2
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• pp.75-81
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• 2017

Objectives Obsessive-compulsive disorder (OCD) is a chronic and disabling psychiatric disorder. The duration of untreated illness (DUI) has been suggested as one of the predictors of clinical course and outcome in various psychiatric disorders. There is increasing evidence that cognitive dysfunction is associated with the prognosis of OCD. The aim of this study was to investigate the influence of DUI on the neurocognitive functions in patients with OCD. Methods Sixty-two patients with a DSM-IV diagnosis of OCD from the outpatient clinic were included in this study. We defined the short DUI if the DUI was 2-year or less and the long DUI if it was longer than 2-year. Neurocognitive functions were assessed by visuospatial memory function test and 4 subsets of K-WAIS such as vocabulary, arithmetic, block design and picture arrangement. Differences in neurocognitive functions as well as clinical variables between OCD patients with short DUI and those with long DUI were investigated. Correlation analyses were also performed to determine the correlation between DUI and neurocognitive functions. Results Compared with the short DUI group, the long DUI group performed worse in the block design test, which measures executive function. The long DUI group also had a higher level of compulsive symptom severity than the short DUI group. However, the DUI was not correlated with neurocognitive functions. Conclusions Findings in this preliminary study suggest that the long DUI in patients with OCD is associated with more severe executive dysfunction. Studies with larger samples and longitudinal design are needed to further confirm the prognostic role of the DUI in OCD.