• Journal of Digital Convergence
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• v.15 no.6
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• pp.259-271
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• 2017

The present study was designed to examine the impact of socioeconomic, health-related, and health behavioral factors on the health-related quality of life (HRQoL) of the Korean elderly by gender. The subjects comprised 688 men and 898 women aged 65 or more who had participated in the Sixth Korea National Health and Nutrition Examination Survey conducted in 2014. The associations of factors with the HRQoL as measured with the European Quality of Life 5 Dimensions (EQ-5D) Index were examined in a general linear model. The most influential factor on the HRQoL was depression in both men and women. The perceived health status and walking activity were also associated with the HRQoL in both men and women. The living arrangement and educational status were associated with the HRQoL in women, while the body mass index was associated with the HRQOL in men. Depression management and the promotion of walking activity are essential to the HRQoL of the Korean elderly. Particular attention must be paid to the HRQoL of older women who live alone and have a lower level of education.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.337-343
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• 2014

This paper presents a continuum-based shape design sensitivity analysis(DSA) method for crack propagation problems using a reproducing kernel method(RKM), which facilitates the remeshing problem required for finite element analysis(FEA) and provides the higher order shape functions by increasing the continuity of the kernel functions. A linear elasticity is considered to obtain the required stress field around the crack tip for the evaluation of J-integral. The sensitivity of displacement field and stress intensity factor(SIF) with respect to shape design variables are derived using a material derivative approach. For efficient computation of design sensitivity, an adjoint variable method is employed tather than the direct differentiation method. Through numerical examples, The mesh-free and the DSA methods show excellent agreement with finite difference results. The DSA results are further extended to a shape optimization of crack propagation problems to control the propagation path.

• Journal of Korean Society of Steel Construction
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• v.20 no.2
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• pp.237-246
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• 2008

The cross-sections of continuous multi-span beams sometimes suddenly increase, or become stepped, at the interior supports of continuous beams to resist high negative moments. The three-dimensional finite-element program ABAQUS (2006) was used to analytically investigate the inelastic lateral-torsional buckling behavior of stepped beams subjected to pure bending moment and resulted in the development of design equations. The flanges of the smaller cross-section were fixed at 30.48 by 2.54 cm, whereas the width and/or thickness of the flanges of the larger cross-section varied. The web thickness and height of beam was kept at 1.65 cm and 88.9 cm, respectively. The ratios of the flange thickness, flange width, and stepped length of beams are considered analytical parameters. Two groups of 27 cases and 35 cases, respectively, were analyzed for double and single stepped beams. The combined effects of residual stresses and geometrical imperfection on inelastic lateral-torsional buckling of beams are considered. First, the distributions of residual stress of the cross-section is same as shown in Pi, etc (1995), and the initial geometric imperfection of the beam is set by central displacement equal to 0.1% of the unbraced length of beam. The new proposed equations definitely improve current design methods for the inelastic LTB problem and increase efficiency in building and bridge design. The proposed solutions can be easily used to develop new design equation for inelastic LTB resistance of stepped beams subjected to general loading condition such as a concentrated load, a series of concentrated loads or uniformly distributed load.

• Journal of the Korean Geographical Society
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• v.39 no.4
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• pp.562-584
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• 2004

This paper intends to identify the structure of homogeneous regions and functional regions in Seoul based on B.J.L. Berry's ‘general field theory of spatial behavior’. The structure of homogeneous regions by using socio-economic variables can explain how the structural elements of the city are arranged. It can be ssid that Seoul has shifted towards more complicated and differentiated features in terms of homogeneous regions. The different patterns are found between the northern part to Han River where old torn areas are located and the southern part to Han River where newly urbanized areas are located. Usually, the concentric pattern and the sectoral pattern coexist, which is enhanced moving from CBD to the outskirt area. The distribution of different social classes shows irregular pattern similar to the variation of living environment. The social gap is expected to be more widening between new towns and old towns. The analysis of spatial movement pattern shows no clear hierarchical order because of current shifts towards both multi-nuclear pattern and spatial dispersion. The functional regions show duplicated structure overlapping their boundaries each other. The ‘general field theory of spatial behavior’ strongly suggests that spatial interactions among sub-areas in the city are differentiated from the basic characteristics and function of each sub-area. The attributes of homogeneous regions and functional regions are interrelated in the characteristics of isomorphic nature.

• Journal of Radiation Protection and Research
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• v.29 no.1
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• pp.65-71
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• 2004

A multi-attribute utility analysis was investigated as a tool for the decision support of countermeasures in early phase of a nuclear accident. The utility function of attributes was assumed to be the second order polynomial expressions, and the weighting constant of attributes was determined using a swing weighting method. Because the main objective of this study focuses on the applicability of a multi-attribute utility analysis as a tool for the decision support of countermeasures in early phase of a nuclear accident, less quantifiable attributes were not included due to lack of information. In postulated accidental scenarios for the application of the designed methodology, the variation of the numerical values of total utility for the considered actions, e.g. sheltering, evacuation and no action, was investigated according to the variation of attributes. As a result, it was shown that the numerical values of total utility for the actions are distinctly different depending on the exposure dose and monetary value of dose. As increasing in both attributes, the rank of the numerical values of total utility increased for evacuation, which is more extreme action than for sheltering, while that of no action decreased. As expected probability of high dose is higher, the break-even values for the monetary value of dose, which are the monetary value of dose when the ranking of actions is changed, were lower. In audition, as aversion psychology for dose is higher, the break-even values for dose were lower.

• Journal of Venture Innovation
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• v.3 no.1
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• pp.101-115
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• 2020

In the era of the 4th Industrial Revolution customers living began to come out, not inside the purchase funnel. Due to the diversity of product selection and the increase in digital channels, the way customers search for information and purchase it is changing innovatively. So, the customer journey in the digital age is much more complicated than the traditional funnel model suggests. Unlike many previous studies, this study was conducted for 1,200 customers in four product groups of fashion, automobile, cosmetics, and online shopping malls. As a result of the study, we investigated how digital self-efficacy plays a role in purchasing in a series of processes in which digital experience affects customer satisfaction and finally affects purchase. As a theoretical implication, as a result of introducing and testing digital self efficacy as moderated mediation effect. the digital self-efficacy between customer satisfaction and customer loyalty were determined to play a moderated mediation effect role. As a practical implication, it was necessary to actively utilize digital marketing for customers with high digital self-efficacy, but it was suggested that customers with low digital self-efficacy need to be careful about digital marketing fatigue.

• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.934-941
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• 2002

It is important to consider the effect of member size when estimating the ultimate strength of a concrete flexural member because the strength always decreases with an increase of member size. In this study, the size effect of a reinforced concrete (RC) beam was experimentally investigated. For this purpose, a series of beam specimens subjected to four-point loading were tested. More specifically, three different effective depth (d$\approx$15, 30, and 60 cm) reinforced concrete beams were tested to investigate the size effect. The shear-span to depth ratio (a/d=3) and thickness (20 cm) of the specimens were kept constant where the size effect in out-of-plane direction is not considered. The test results are curve fitted using least square method (LSM) to obtain parameters for the modified size effect law (MSEL). The analysis results show that the flexural compressive strength and the ultimate strain decrease as the specimen size increases. In the future study, since $\beta_1$ value suggested by design code and ultimate strain change with specimen size variation, a more detailed analysis should be performed. Finally, parameters for MSEL are also suggested.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.486-491
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• 2008

This paper describes a model identification method that has been applied to a commercial 12-inch RTP (rapid thermal processing) equipment with an ultimate aim to develop a high-performance advanced controller. Seven thermocouples are attached on the wafer surface and twelve tungsten-halogen lamp groups are used to heat up the wafer. To obtain a MIMO balanced state space model, multiple SIMO (single-input multiple-output) identification with highorder ARX models have been conducted and the resulting models have been combined, transformed and reduced to a MIMO balanced state space model through a balanced truncation technique. The identification experiments were designed to minimize the wafer warpage and an output linearization block has been proposed for compensation of the nonlinearity from the radiation-dominant heat transfer. As a result from the identification at around 600, 700, and $800^{\circ}C$, respectively, it was found that $y=T(K)^2$ and the state dimension of 80-100 are most desirable. With this choice the root-mean-square value of the one-step-ahead temperature prediction error was found to be in the range of 0.125-0.135 K.

• Journal of the Korean Data and Information Science Society
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• v.27 no.3
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• pp.677-687
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• 2016

Among lots of sabermetric statistics for baseball batters' ability, the wins above replacement (WAR) is the most popular statistic in MLB. However, there exists a difficulty applying WAR to KBO, since KBO data do not have position adjustment, league adjustment and park factor which are essential in calculating WAR. In this paper, using five statistics for both KBO and MLB qualified batters, we propose hitting ability index (HAI), an alternative sabermetric indices to represent batters' ability. Comparing HAI with WAR of MLB batters, we evaluate the validity of HAI and then applied HAI to 2015 KBO data in which HAI is analyzed statistically with respect to different teams, ages, and positions. Moreover, the linear relationship between KBO batter's HAI and their annual salary is discussed. Grouping 46 KBO batters based on confidence region of the regression model for annual salary, we also statistically investigate batter's annual salary in these groups with respect to several factors.

• Journal of the Korea Concrete Institute
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• v.14 no.2
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• pp.216-222
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• 2002

With deterioration of the nation's infrastructure comes the growing, need for effective means of rehabilitating structures. Possibly one for the most challenging tasks is to upgrade the overall capacity of concrete structure. Therefore, considerable efforts are still being made to develop new construction materials. Rehabilitation of damaged RC structures occasionally requires the removal and replacement of concrete in the tension zone of the structural members. Typical situation where the tension zone repair is necessary is when the concrete in the tension zone in beams or slabs has spalled off as a result of corrosion in the bottom reinforcing bars or due to extensive fire. The rehabilitation of such conditions normally involves the removal of the concrete beyond the reinforcement bars, cleaning or replacing the tensile bars and reinstatement of concrete to cover the steel bars the original shape and size. This study focused on the flexural behavior of reinforced concrete beams strengthened by steel strand and carbon fiber sheet in the tension zone. The properties of beams are 15$\times$25 cm rectangular and over a 200cm span. Test parameters in this experimental study were strengthening methods, jacking volume, the number of sheet. We investigated the flexural behavior of simply supported RC beams which are strengthened with the carbon fiber sheet, monotonic loads. Attention is concentrated upon overall bending capacity, deflection, ductility index, failure mode and crack development of repaired and rehabilitated beams.