• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.50-56
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• 2017

The perimeter structure in high-rise buildings, which plays a major role in resisting lateral forces, is generally formed by the orthogonal placement of the beam and column, but currently various grid patterns are implemented. In a previous study, the adaptability of the $IsoTruss^{(R)}$ grid (ITG) as a perimeter structure was examined. In this study, a method of estimating the required cross sectional area of a member in a preliminary design is proposed. The members of the perimeter structure are placed in three planes, perpendicular (PPR), parallel (PPL) and oblique (POQ) to the lateral loading, and the stiffness of the members in the POQ was taken into account by projecting them onto the PPL or PPR. Three models are established for member size zoning through the height of the building, in order to investigate the effect of the shear and moment in the calculation of the required cross sectional area. To examine the effectiveness of this study, a 64-story building is designed and analyzed. The effect of the member size zoning was examined by comparing the maximum lateral displacement, required steel amount, and axial strength ratio of the columns. Judging from the maximum lateral displacement, which was 97.3% of the allowable limit, the proposed formula seems to be implemental in sizing the members of an ITG structure at the initial stage of member selection.

• Journal of Biomedical Engineering Research
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• v.24 no.4
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• pp.259-266
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• 2003

Non-rigid registration between different modality images with shape deformation can be used to diagnosis and study for inter-patient image registration, longitudinal intra-patient registration, and registration between a patient image and an atlas image. This paper proposes a hierarchical registration method using bodily tissue based segmentation for registration between color images and CT images of the Visible Human leg areas. The cross-sectional color images and the axial CT images are segmented into three distinctive bodily tissue regions, respectively: fat, muscle, and bone. Each region is separately registered hierarchically. Bounding boxes containing bodily tissue regions in different modalities are initially registered. Then, boundaries of the regions are globally registered within range of searching space. Local boundary segments of the regions are further registered for non-rigid registration of the sampled boundary points. Non-rigid registration parameters for the un-sampled points are interpolated linearly. Such hierarchical approach enables the method to register images efficiently. Moreover, registration of visibly distinct bodily tissue regions provides accurate and robust result in region boundaries and inside the regions.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.34-46
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• 2020

In order to supply stable natural gas in the future, it is necessary to forecast the demand in advance and secure the quantity of supply. In this paper, we propose a method of estimating the demand function of industrial natural gas, which is the core of the increase of domestic natural gas demand in the future. The cross-sectional data of 304 domestic industries were used to estimate the demand function of the industrial natural gas, and the effect of industry specific characteristics such as capital investment, manufacturing cost. Finally, the least absolute deviation estimation method which is robust to outliers and does not assume the homogeneity of the error term and the normality, And the results were derived. In addition, the economic value of industrial city gas was estimated using the price elasticity of industrial city gas. Therefore, it can be seen that the continuous expansion and supply of city gas to the industrial sector is beneficial at the national level, and the government needs to promote expansion through the industrial city gas support policy.

• Journal of the Korean Society of Physical Medicine
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• v.17 no.1
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• pp.93-108
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• 2022

PURPOSE: This review sought to confirm the correlation between dual-task gait and cognitive function in cognitively impaired and healthy older adults. METHOD: We used four databases (DBs), Pubmed, Cochrane library, Kmbase, and Koreamed. Searches were carried out according to the PICOS method, P (participants) were the elderly (above 65 years) with cognitive decline, I (intervention) was walking with dual tasks, C (control group) comprised the elderly without cognitive decline, O (outcome) was the correlation between gait and cognitive function and S (study) was the cross-sectional study. For the methodological quality assessment of each study, we used the Quality Assessment Tool for Observation Cohort and Cross-Sectional Studies provided by the National Institutes of Health (NIH). RESULTS: A total of 10 articles were included in this systematic review. For the components of gait, we used pace, rhythm, and variability and we observed that mild cognitive impairment mostly causes low gait performance while performing dual tasks. Among the 10 articles, 9 articles studied pace, of which 7 showed significant results. However, 2 were not significant. Also, 1 article that studied rhythm and 3 articles that studied variability showed significant results. The methodological quality of the 10 studies was fair. CONCLUSION: Gait pace was found to have a high correlation between memory, which is a cognitive ability, and overall cognitive function. It was observed that older adults with mild cognitive impairment have reduced gait pace in single-task walking, and further decrease in dual-task gait pace shows the correlation between memory and gait pace during walking.

• Journal of the Society of Disaster Information
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• v.19 no.3
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• pp.737-746
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• 2023

Purpose: Ground subsidence due to cavity can bring about various problems, such as casualties, decrease of the safety of the structures, and indirect social costs. Therefore, ground subsidence should be prevented through the exploration and recovery of the cavity under the pavements. Method: In this study, GPR exploration method was carried out on both actual roadway and mock-up site to compensate for the problems caused by excavation and restoration process. Result: This study compared the cavity scales obtained from GPR exploration results and the direct excavation of the identified cavity. It was confirmed that the predicted soil depth by GPR exploration was similar to the identified soil depth, but the predicted cavity scale by GPR exploration overestimated the longitudinal and cross-sectional widths compared to the identified cavity scale. Conclusion: Based on the correlation between the predicted cavity scales by GPR exploration, it is possible to qualitatively estimate the cavity scales using the empirical formula proposed in this study.

• Journal of Environmental Health Sciences
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• v.49 no.3
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• pp.134-148
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• 2023

Background: The conducting of health effect surveys (HESs) in environmentally contaminated vulnerable areas (ECVAs) by the central and local governments has been increasing apace with the increase in demand for HESs since the Environmental Health Act was enacted in South Korea in 2008. Objectives: This study aimed to review the HESs of residents in ECVAs conducted in South Korea. Methods: An analysis was performed on 125 reports obtained from the Environment Digital Library, PRISM, and local government websites after selecting from 803 projects obtained as ECVAs from the Korea ON-Line E-Procurement System (1997~2021), National Institute Environment Research (2000~2021), and Korea Environmental Industry and Technology Institute (2009~2021). The reports were classified by background (residents' demand, HES, and more), research design (cross-sectional study, cohort, ecological study, and panel), pollution source (abandoned metal mine (AMM), industrial complex (IC), and more), and assessment method of exposure and health effects. The survey area was converted into administrative district codes for geographical mapping. Results: There were 37, 34, 18, and 10 cases associated with AMM, IC, waste incinerators, and coal-fired power plants, respectively. Most of the studies conducted were cross-sectional studies and ecological studies. The proportion of epidemiological investigations by residents' demand showed an increase from 0.0% to 8.9% for the central government while decreasing from 16.7% to 14.3% for local governments after 2008 compared to before 2008. HESs increased at both the central and local government levels since 2014. For the evaluation method, 365 environmental hazards, 319 health outcomes, and 302 biological markers were investigated, with the most commonly investigated items being metals, cancer, and blood metals. Conclusions: HESs of residents in ECVAs in South Korea have been continuously developed both quantitatively and qualitatively. Future improvements are expected, and systematic review and classification of the HESs is warranted.

• Journal of Korean Association for Spatial Structures
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• v.20 no.2
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• pp.39-49
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• 2020

In this study, we will develop a hybrid cross-sectional shape of steel inserted type glued-laminated timber that can improve the strength of structural glued-laminated timber and maximize the ductility by using steel plate with excellent tensile and deformation ability. A total of three specimens were fabricated and the flexural performance test was carried out to evaluate the structural performance of the steel inserted type glued-laminated timber. In order to compare the effect of steel inserted glued-laminated timber, one structural glued-laminated timber test specimen composed of pure wood was manufactured. In addition, in order to evaluate the adhesion performance of the steel inserted, one each of a screw joint test specimen and a polyurethane joint test specimen was prepared. As a result, all the specimens showed the initial crack in the finger joint near the force point. This has been shown to be a cause of crack diffusion and strength degradation. The use of finger joints in the maximum moment section is considered to affect the strength and ductility of the glued-laminated timber beam. Polyurethane-adhesive steel inserted glued-laminated timber showed fully-composite behavior with little horizontal separation between the steel plate and glued-laminated timber until the maximum load was reached. This method has been shown to exhibit sufficient retention bending performance.

• Structural Engineering and Mechanics
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• v.74 no.5
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• pp.635-655
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• 2020

The sag effect of long stay cables is one of the key factors restricting further increase in the span of cable-stayed bridges. Based on the formerly proposed concept of long stay cables lifted by an auxiliary suspension cable in cross-strait cable-stayed bridges, corresponding static approximate calculations and analytical theory based on catenary and parabolic cable configurations are established. Taking a main span 1400 m cable-stayed bridge as the research object, three typical lifting conditions and the whole process of auxiliary cable lifting are analyzed and discussed. The results show that the sag effect is effectively reduced. The support efficiency is only improved when the cables are lifted above the original cable chord. Reduction of the horizontal component force of the cable is limited. The equivalent elastic modulus and the vertical support stiffness of the lifted cables are significantly increased with increased horizontal projection length and not sensitive to the change of the lifting point position. The scheme of lifting the cable to the chord midpoint is more economical because of the less steel required for the auxiliary suspension cable, but its effect on improving the vertical support efficiency is limited. The support efficiency is better when the cable is lifted to the cable end tangential to the original cable chord, but the lifting force and the cross-sectional area of the auxiliary suspension cable are doubled. The approximate calculation results of the lifted cables are very close to the numerical analysis results, which verifies the applicability of the approximation method proposed in this study. The results of parabolic approximation calculations are approximately equal to that of catenary cable geometry. As the parabolic approximation analysis theory of lifted cables is more convenient in mathematical processing, it is feasible to use parabolic approximation analysis theory as the analytical method for the conceptual design of lifted cables of super-long span cable-stayed bridges.

• Research in Community and Public Health Nursing
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• v.13 no.3
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• pp.423-432
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• 2002

This study was conducted to test the validity of characteristics of family nursing phenomena in Korea identified in a previous study by Yoon, S. Y, et al. (1999). Data for this study were collected from 355 (first measurement 186, second measurement 169) nurses whose family nursing careers were more than one year using a cross sectional survey method. The distribution per one characteristic ranged between 0 to 5. The phenomena that had two or more characteristics and had a score of 3.0 points or more included disturbance in marital role', 'disturbance in family communication', 'inappropriate family coping', 'lack of family intimacy', 'unhealthy life style', 'deficit of financial management skill and support', 'inadequate care management sick member', and' inadequate home-making'. The essential characteristics of the 8 phenomena presented above included 27 items. Further studies on family nursing phenomena in Korea are needed to support the evidence through surveys of families in the field. A reconfirmation study, as well as qualitative research on the low validity of the characteristics, needs to be more performed in the future.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.3
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• pp.66-73
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• 2019

Recently, FDM-type 3D printer technology has been developed, and efforts have been made to improve the output formability and characteristics further. Through this, 3D printers are used in various fields, and printer technologies are suggested according to usage, such as FDM, SLA, DLP, and SLM. In particular, the FDM method is the most widely used, and the FDM method technology is being developed further. The characteristics of the output are produced by the FDM-type 3D printer, which is determined by various factors, and particularly the perspective of the Inter-Layer Fill Factor, which is the volume ratio of the laminated material that exerts a direct influence. In this study, the Inter-Layer Fill Factor is theoretically obtained by presenting the internal space between each layer according to the laminate thickness as a cross-sectional shape model, and the cross section of the actual laminated sample is compared with the theoretical model through experiments. Then, the equation for the theoretical model is defined, and the strength change according to each condition (tensile strength of material, reduction slope, strength reduction rate, and output strength) is confirmed. In addition, we investigated the influence on the correlation and strength between laminate thickness and the Inter-Layer Fill Factor.