• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.6
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• pp.485-492
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• 2014

In regards to natural disasters, vulnerability analysis is a component of the disaster risk analysis with one of its objectives as a basis for planning priority setting activities. The volcano eruption raises many casualties and property in the surrounding area, especially when the volcano located in densely populated areas. Volcanic eruptions cannot be prevented, but the risk and vulnerability can be reduced which involve careful planning and preparations that anticipate a future crisis. The social vulnerability as social inequalities with those social factors can influence the susceptibility of various groups to harm and govern their ability to respond. This study carried out the methods of Social Vulnerability Index (SoVI) to measure the socially created vulnerability of the people living in Merapi proximal hamlets in Central Java, Indonesia that refers to the socioeconomic and demographic factors that affect the resilience of communities in order to describe and understand the social burdens of risk. Social vulnerability captured here, using a qualitative survey based-data such as interviews to local people with random ages and background to capture the answer vary, also interviews to stakeholders to help define social vulnerability variables. The paper concludes that by constructing the vulnerability index for the hamlets, the study reveals information about the distribution and causes of social vulnerability. The analysis using SoVI confirms that this method works well in ensuring that positive values indicating high social vulnerability and vice versa.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.6
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• pp.529-538
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• 2016

The simplified plate theory is presented for static and free vibration analysis of power-law(P) and sigmoid(S) Functionally Graded Materials(FGM) plates. This theory considers the parabolic distribution of the transverse shear stress, and satisfies the condition that requires the transverse shear stress to be zero on the upper and lower surfaces of the plate, without the shear correction factor. The simplified plate theory uses only four unknown variables and shares strong similarities with classical plate theory(CPT) in many aspects such as stress-resultant expressions, equation of motion and boundary conditions. The material properties of the plate are assumed to vary according to the power-law and sigmoid distributions of the volume fractions of the constituents. The Hamilton's principle is used to derive the equations of motion and Winkler-Pasternak elastic foundation model is employed. The results of static and dynamic responses for a simply supported FGM plate are calculated and a comparative analysis is carried out. The results of the comparative analysis with the solutions of references show relevant and accurate results for static and free vibration problems of FGM plates. Analytical solutions for the static and free vibration problems are presented so as to reveal the effects of the power law index, elastic foundation parameter, and side-to-thickness ratio.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.2
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• pp.121-128
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• 2020

The purpose of this study is to investigate the distribution patterns of displacement and acceleration fields in a nonlinear soil ground based on the interaction of high-speed train, wheel, rail, and ground. For this purpose, a high-speed train in motion was modeled as the actual wheel, and the vertical contact of wheel and rail and the lateral contact, caused by meandering motion, were simulated; this simulation was based on the moving mass analysis. The soil ground part was given the nonlinear behavior of the upper ground part by using the modified the Drucker-Prager model, and the changes in displacement and acceleration were compared with the behavior of the elastic and inelastic grounds. Using this analysis, the displacement and acceleration ranges close to the actual ground behavior were addressed. Additionally, the von-Mises stress and equivalent plastic strain at the ground were examined. Further, the equivalent plastic and total volumetric strains at each failure surface were examined. The variation in stresses, such as vertical stress, transverse pressure, and longitudinal restraint pressure of wheel-rail contact, with the time history was investigated using moving mass. In the case of nonlinear ground model, the displacement difference obtained based on the train travel is not large when compared to that of the elastic ground model, while the acceleration is caused to generate a large decrease.

• Management & Information Systems Review
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• v.36 no.2
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• pp.207-221
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• 2017

The career management concept is changing rapidly in the career management field in recent years. It becomes very difficult to have a lifetime employment within the same firm. As there is career interruption that is pervasive phenomenon in the women's career management area, many academics and practitioners have been interested in it. The purpose of this study was to examine the influence of women's career-interruptions as the effective career strategy on career development actors and career success. To test the effects of the proactive career management of career-interrupted women, data were divided into two groups including proactive career management group and general career management group based on whether career-interruptions are voluntary or not. The results showed that the proactive development actors was significantly different depending on women's proactive career management and general career management group. First, proactive-career women were more self-directed to learn and have a significant impact on developing skills through training. Second, the career successes were not significantly different depending on and general career management group.

• Journal of dental hygiene science
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• v.6 no.1
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• pp.35-39
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• 2006

objective: The purpose of this study was to investigate job satisfaction of dental hygienist who were employed at the private dental clinic in Ulsan, Korea methods: The date obtained from some dental hygienists during 1 month. the survey was performed by face-by-face interview questionnaire consisting of 23 items and 6 point Likert type response format. The respondents were 77 from dental hygienists. The adjusted response rate was 88.5%(77/87). Data were analyzed using frequency distribution, independent T-test, ANOVA, chi-square and correlation. all statistical analyzed were conducted using Statistical Package for SPSS 11.5 result: In each factorial duty contentment, the level of the self-conceit from their own job was the highest. on contrary, the level of their monthly earnings was the lowest. In such a case as there was experience to move to another dental hospital, the job satisfaction was higher than nothing to move. conclusion: The dental hygienist who is in charge of protecting and hygiene of the teeth and the disease of oral has much influence of oral health. job satisfaction the dental hygienists have for their own job can influence themselves and even patients. So, making the job satisfaction higher is necessary to improve the quality of general dental hygiene.

• Journal of dental hygiene science
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• v.17 no.2
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• pp.175-182
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• 2017

From March 1, 2016 to August 31, 2016, 375 dental implant patients between the ages of 30 and 70 years to evaluate their subjective symptoms and satisfaction according to prosthesis methods. The collected data were analyzed using the chi-square distribution test, t-test, one-way analysis of variance, and multiple logistic regression. Of the patients with subjective symptoms of peri-implantitis, 40.5% reported food impaction, 49.1% reported bleeding, 61.1% reported pain, 61.9% reported halitosis, and the overall satisfaction level with the implants was 3.95 points. In the prosthesis methods, implant-teeth connective group showed the lowest level of the food impaction (21.3%), the pain (35.5%), and the halitosis (36.6%) (p<0.001), and the lowest bleeding was the implant single (33.8%) (p<0.05). Patient satisfaction was higher in the implant-teeth connective group (4.06 points) and the group without bone grafting (4.03 points) (p<0.01). Factor analysis showed that implant satisfaction was 0.43 times lower in the single implant group and 0.44 times lower in the implant-implant connective group than in the implant-teeth connective group. As a result of the study, it is expected that the method of extending the life of adjacent teeth and restoring the function of the tooth defect region is an implant-teeth connection method, so that it can be utilized positively through various clinical studies.

• Geophysics and Geophysical Exploration
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• v.13 no.4
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• pp.323-329
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• 2010

Three deconvolution methods were applied to stacked seismic data obtained to investigate gas-hydrates in the Ulleung Basin, East Sea: (1) minimum-phase spiking deconvolution, (2) minimum-phase spiking deconvolution using an averaged wavelet from all traces, and (3) deterministic deconvolution using a wavelet with phases computed from well-logs. We analyzed the resolving property of these methods for lithological boundaries. The first deconvolution method increases temporal resolution but decreases lateral continuity. The second method shows, in an overall sense, similar results to the spiking deconvolution using a minimum phase wavelet for each trace; however, it results in a more consistent and continuous bottom-simulating reflector (BSR) and better resolved sub-BSR reflectors. The results from the third method reveal more detailed internal structures of debris-flow deposits and increased continuity of reflectors; in addition, the seafloor reflection and the BSR appear to have changed to a zero-phase waveform. These properties help more precisely estimate the distribution and reserves of gas hydrates in the exploration area by improving analysis of facies and amplitude of the BSR.

• Journal of the Korean Magnetics Society
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• v.18 no.1
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• pp.19-23
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• 2008

The mixed ferrite $V_xFe_{3-x}O_4$(x=0.0, 0.15, 0.5, 1.0) thin films were prepared by sol-gel method. Their crystallographic and magnetic hyperfine properties have been studied using X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and conversion electron $M\"{o}ssbauer$ spectroscopy(CEMS). The crystal structure is found to be cubic spinel throughout the series($x{\leq}1.0$), and the lattice parameter $a_0$ increases linearly with increasing V content. XRD, XSP and CEMS indicate that $V^{3+}$ substitution for $Fe^{3+}$ in B-site is superior to $V^{2+}$ substitution for $Fe^{2+}$ in B-site. It is noticeable that both quadrupole shift and hyperfine field decreases with increasing V composition, suggesting the change of local symmetry and accompanying line-broadening. The line-broadening on CEMS spectra can be explained by the distribution of magnetic hyperfine fields.

• Korean Journal of Plant Taxonomy
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• v.40 no.1
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• pp.50-58
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• 2010

The nutlet morphology and pericarp structure of 14 taxa (4 taxa of the genus Glechoma and related taxa) were studied by light and scanning electron microscopy, and a detailed description of nutlet morphological features for all examined taxa is provided. The shape of the nutlet is ovate to elliptic. Its size is 1.36-3.83 mm in length and 0.80-2.65 mm in width. The largest one was found in Marmoritis rotundifolia, while the smallest one was in Agastache nepetoides. Three different surface types were recognized in the studied taxa based on differences in cell outline and cell boundary relief (rectangular, pitted, and ridged negative reticulate-cell). Three types of trichome (uni-cellular non-glandular trichome, multi-cellular non-glandular trichome, and peltate glandular trichome) were distributed in the nutlets. The pericarp is formed in three layers (i.e., exocarp, mesocarp, and endocarp including sclenchyma tissue), and the pericarp in the studied species is $39.0-237.5{\mu}m$ thick. The morphological and anatomical features (the nutlet shape, surface type, and trichome distribution) in the genus Glechoma and related taxa are described and discussed.

• Journal of the Korean Society for Railway
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• v.20 no.5
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• pp.569-576
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• 2017

The electromagnetic valve of pneumatic doors of EMUs has a high failure rate due to air leakage because it supplies air on and off to operate the doors repeatedly. The electromagnetic valve is a very important safety component for which a very high reliability is required because failure makes it impossible to operate the passenger cars. However, domestic urban railway operators maintain electronic valves of the EMU door under a fixed cycle with a spare period according to the full overhaul cycle of the EMU. An improvement of the current maintenance cycle was suggested based on the reliability function and mission reliability. Using the statistical program MINITAB for the operational data of EMU line 6, we analyzed the characteristics of the fault distribution and derived the shape and scale parameters of the reliability function. If we limit the specific reliability probability to under a certain failure rate and calculate its statistical parameters, we can calculate the allowable inspection period with mission reliability. Through this study, we suggested a maintenance period based on RCM (reliability centered-maintenance) to improve the reliability of electromagnetic valves from 68% to 95%.