• Journal of Korean Society of Forest Science
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• v.11 no.1
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• pp.25-32
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• 1970

Site-index curves for Pinus densiflora Sieb. et Zucc. grown in the middle part of Korea were developed from stem analysis data by a procedure of guide curve equation $Yt=K-ab^t$ (t=0, 1, 2, ${\cdots}{\cdots}$) and shown in Fig. 2. The stand density expressed as size-number criteria was calculated and the relation of number of tree per hectare and average DBH was presented in Fig. 3, in which soil fertility showed little effect. When this is compared to Reineke's density standards, the Pinus densiflora stand ranks high level of stocking density (Fig. 5). As a measure for estimating timber volume, the angle-summation technique revealed to result wider variation. Constructing hypothetical populations for appraising angle-summation technique, the significance of its application in silvicultural and ecological research are discussed.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.708-712
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• 2008

Piles and pile foundations have been in common use since very early times. Usually function of piles is to carry load to a depth at which adequate support is available. Another important use of piles is to furnish lateral support and nowadays it is getting highlighted due to the wind load, lateral action of earthquake, and so on. After Broms (1964), many researchers have been suggested methods for estimating lateral capacity of pile. But each method assumes different earth pressure distribution and lateral earth pressure coefficient and it gives confusion to pile designers. Lateral earth pressure, essential in lateral capacity estimation, influenced by pile's behavior under lateral load. Prasad and Chari (1999) assumed the rotation point of pile and suggested an equation of ultimate lateral load capacity. In this study, we investigate the depth of rotation point in both homogeneous soil and multi layered soil, and compare to the estimation value by previous research. To model the pile set up in the sand, we use the chamber and small scale steel pile, and rain drop method. Test results show the rotation point is formed where the Prasad and Chari's estimation value, and they also show multi layered condition affects to location of rotation point to be scattered.

• Korea Journal of Hospital Management
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• v.25 no.1
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• pp.13-20
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• 2020

Purposes: This study has the purpose to the improvement of health promotion for local residents through delivery of high-quality medical service by improving imbalance of medical use and seeking an improvement plan for accessibility of effective medical service by understanding the pattern of medical use by region. Methodology: As for the method, this study derived results at the significance level of p<0.05 through chi square test(χ² test) and Generalized Estimating Equation(GEE) SAS 9.4 version by using the data of the 7th Korean Longitudinal Study of Ageing 2018. Findings: Study results show that local residents use medical service such as hospitalization care and outpatient visit more as compared to the residents in Gyeonggi-do/large or medium-sized cities. The more the number of chronic disease, the more they select hospitalization care rather than outpatient visit. Results also show that patients engaged in labour tend to select outpatient treatment rather than hospitalization treatment. Meanwhile, severity of disease turned out to be higher amongst medical care beneficiaries than that of national health insurance patients when comparing the types of medical security. Practical Implications: In stead of solving the problem of the difference in medical use by region from the aspect of income and economic level, an integrative solution shall be provided putting viewpoint on the social phenomenon suited to the changes of the times. This study suggests a plan for using a health and medical community care center that acts as a gate keeper of regional medical service.

• Genomics & Informatics
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• v.7 no.1
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• pp.20-25
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• 2009

Rheumatoid arthritis (RA) is a chronic autoimmune disorder that is characterized by inflammation of the synovial tissue and deterioration of the joint and bone. A recent study reported a potential gene-environment interaction between HLA-DR and smoking. The present study investigated whether a specific gene was related to the association between smoking and the severity of RA (rheumatoid factor levels > 20 IU/ml). We used the resources of the NARAC family collection of GAW 15 databases, and 1139 subjects with RF>20 IU/ml were included in the current analysis. The linkage panel contained 5858 SNP markers, and 5744 SNPs passed quality control criteria. Linear regression analyses, using PLINK software and generalized estimating equation regression models, were used to test for associations between the SNPs and the severity of RA according to smoking groups. Two major findings were established. First, the severity of RA in smokers was associated with rs703618 (p=$6{\times}10^{-5}$), which lies in the intronic region of the stabilin 2 (STAB2) gene on chromosome 12. Second, there were significant differences in the levels of RF between 'ever smokers' and 'never smokers' according to the rs703618 genotype (G/G, A/G, A/A). We investigated whether a specific gene acts as a mediator between smoking and the severity of RA and found that the STAB2 gene could affect this relationship. Our finding indicates that smoking may mediate RA severity by affecting the expression level of a specific gene.

• Journal of the Semiconductor & Display Technology
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• v.9 no.4
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• pp.87-91
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• 2010

Charged micro-particles are widely used as the key components for many electrical applications such as an e-paper, a touch panel, a printer toner and an electronic ink. Among them, the e-paper is an emerging reflective type display using the charged particles that has the advantages of the extremely low power consumption and sunlight readability. To create images on the e-paper, we confine black positively-charged and white negatively-charged particles between bottom and top electrodes and selectively apply the electric field. When the Coulomb force by an applied electric field is greater than the adhesion force between the charged particle and the electrode, the particles' transition happens resulting in the change of color between black and white. Therefore, the adhesion force is a very important factor for designing and estimating e-paper's operation. In this study, we constructed a basic model for particle's transition and an adhesion force equation describing particle's transition with three different forces: electrostatic image force, Van der Waals force and gravitational force. The simulation results showed that the gravitational force is negligible for the interesting range for the charge and the radius, and the adhesion force can be strongly dependent on the particle's charge and radius.

• Journal of Korean Academy of Nursing
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• v.47 no.6
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• pp.828-841
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• 2017

Purpose: This study aimed to analyze the impact of increasing the supply of newly licensed nurses on improving the hospital nurse staffing grades for the period of 2009~2014. Methods: Using public administrative data, we analyzed the effect of newly licensed nurses on staffing in 1,594 hospitals using Generalized Estimating Equation (GEE) ordered logistic regression, and of supply variation on improving staffing grades in 1,042 hospitals using GEE logistic regression. Results: An increase of one newly licensed nurse per 100 beds in general units had significantly lower odds of improving staffing grades (grades 6~0 vs. 7) (odds ratio=0.95, p=.005). The supply of newly licensed nurses increased by 32% from 2009 to 2014, and proportion of hospitals whose staffing grade had improved, not changed, and worsened was 19.1%, 70.1%, and 10.8% respectively. Compared to 2009, the supply variation of newly licensed nurses in 2014 was not significantly related to the increased odds of improving staffing grades in the region (OR=1.02, p=.870). Conclusion: To achieve a balance in the regional supply and demand for hospital nurses, compliance with nurse staffing legislation and revisions in the nursing fee differentiation policy are needed. Rather than relying on increasing nurse supply, retention policies for new graduate nurses are required to build and sustain competent nurse workforce in the future.

• Journal of Ocean Engineering and Technology
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• v.32 no.5
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• pp.324-332
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• 2018

It is known that damages to the subsea cables used for electric power transmission between islands and countries, including renewable energy from offshore wind power, current, tides, etc., cost much to restore, which causes social and economic losses. Various types of fishing rigs and anchors have been reported to be the greatest hazards to subsea cables. It is possible to design and construct a suitable protection facility for a subsea cable by precisely estimating the underwater behavior of such hazardous apparatuses. In this study, numerical simulations of the underwater behaviors of various hazardous apparatuses were carried out using fluid-structure interaction (FSI) analysis as a basic study to simulate the actual behavior phenomena of hazardous apparatuses in relation to a subsea cable. In addition, the underwater drop characteristics according to the types of hazardous apparatuses were compared. In order to verify the accuracy of the FSI analysis method used in this study, we compared the test results for underwater drops of a steel ball bearing. Stock anchors, stockless anchors, and rocket piles, which were actually reported to be the cases of damage to subsea cables along the southwest coast of Korea, were considered as the hazardous apparatuses for the numerical simulations. Each hazardous apparatus was generated by a Lagrangian model and coupled with the fluid domain idealized by the Eulerian equation to construct the three-dimensional FSI analysis model. The accuracy of the numerical simulation results was verified by comparing them with the analytical solutions, and the underwater drop characteristics according to the types of hazard apparatuses were compared.

• 한국환경농학회:학술대회논문집
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• 2011.07a
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• pp.207-222
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• 2011

Relationships between soil saturated hydraulic conductivity ($K_s$) and porosity (${\phi}$) have been developed over many years; however, use of these relationships for evaluating rain-induced seals is limited mainly because of difficulties in estimating seal pore-size characteristics. The objectives of this study were to evaluate the $K_s$ of soil surface seals over a range of thicknesses, where seal thickness was determined using a High-Resolution-Computed-Tomography (HRCT) scanner, and to investigate relationships between $K_s$ and ${\phi}$ of developing seals in samples with equivalent diameters (e.d.) ${\geq}15\;{\mu}m$. A Mexico silt loam soil was packed to a bulk density (${\rho}_b$) of $1.1\;Mg\;m^{-3}$ in cylinders 160-mm i.d. by 160-mm long and subjected to $61-mm\;h^{-1}$ simulated rainfall having a kinetic energy (KE) of $25\;J\;m^{-2}\;min^{-1}$ for 7.5, 15, 30, and 60 min to create a range in seal development. Thicknesses of the seal layers were determined by analysis of HRCT images of seals. The $K_s$ values of the seals were estimated using an effective $K_s$ value ($K_{s-eff}$). The $K_s-{\phi}$ relationship was described by a Kozeny and Carmen equation, $K_s=B{\phi}^n$; where B and n are empirical constants and n = 31. This approach explained 86% of the variation between $K_s$ and ${\phi}$ within the soil seals. Knowledge of surface seal information and hydraulic conductivity can provide useful information to use in management of sites prone to sealing formation.

• Quality Improvement in Health Care
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• v.25 no.2
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• pp.44-55
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• 2019

Purpose: To investigate whether changes in Medical Aid (MA) status are associated with unmet need and catastrophic health expenditure (CHE). Methods: Data from the 2010 to 2014 Korea Health Panel (KHP) were used. The impact of changes in annual MA status ('MA to MA,' 'MA to MA Exit,' 'MA Exit to MA,' and 'MA Exit to MA Exit') on unmet need (all-cause and financial) and CHE (10% and 40% of household capacity to pay) were examined using the generalized estimating equation (GEE) model. Analysis was conducted separately for MA type I and II individuals. Results: In 1,164 Medical Aid type I individuals, compared to the 'MA to MA' group, the 'MA to MA Exit' group had increased likelihoods of all-cause and financial unmet need. This group also showed higher likelihoods of CHE at the 10% standard. The 'MA Exit to MA Exit' group showed increased likelihoods at the 10% and 40% CHE standards. In 852 type II recipients, the 'MA to MA Exit' group had higher likelihoods of CHE at the 10% standard. Conclusions: Type 1 MA exit beneficiaries had higher likelihoods of all-cause and financial unmet need, along CHE at the 10% standard. Type I 'MA Exit to MA Exit' beneficiaries also showed higher likelihoods of CHE at the 10% and 40% standards. In type II recipients, MA exit beneficiaries had higher likelihoods of CHE at the 10% standard. The results infer the importance of monitoring MA exit beneficiaries as they may be vulnerable to unmet need and CHE.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.5
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• pp.1070-1075
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• 2013

In this research, we describe a security robot system and ongoing research results to control human's wrong direction in order to forbid human to enter security zone. Proposed robot system surveils a security area with equipped laserscanner sensor usually. When it detect walking human who is for the area, robot calculates his velocity vector, plans own path to forestall and interrupts him who want to head restricted area and starts to move along the estimated trajectory. The walking human is assumed to be a point-object and projected onto an scanning plane to form a geometrical constraint equation that provides position data of the human based on the kinematics of the mobile robot. While moving the robot continues these processes for adapting change of situation. After arriving at an opposite position human's walking direction, the robot advises him not to be headed more and change his course. The experimental results of estimating and tracking of the human in the wrong direction with the mobile robot are presented.