• Composites Research
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• v.18 no.4
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• pp.8-13
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• 2005

Rotating circular disks are widely used in data storage devices as well as in traditional industrial machines. Faster rotating speed is required in data storage devices for higher data transfer rate. In this Paper an application of composite materials to CD is proposed to increase critical speeds and the strength analysis was performed. A differential equation of displacement is derived for the analytic stress distribution of rotating polar orthotropic disk. The stress distributions for typical GFRP and CFRP disks and the maximum allowable speeds subjected to a constraint of tensile strength are presented in addition to polycarbonate disk. The results show that the application of CFRP to rotating disk can increase the maximum allowable rotating speed but this may not be applicable to GFRP disk.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.60-65
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• 2004

Kim et al. described and compared other methods of measuring stress triaxiality using the displacements near the side necking, proved the validities of these models and explored the effect of location where the displacements are measured using three-dimensional finite element analysis for a standard CT specimen with 20% side-grooves. In this paper, the applicability of these models to various specimen and materials are examined in detail. To consider the effects of side groove, thickness of specimen, crack length, specimen geometry and strain hardening exponents, three-dimensional finite element simulation has been performed for various specimen geometries. For a case without a side groove, in the whole the difference between the stress triaxilaity analytically evaluated and directly determined is similar. For a case with a 20% side groove the stress triaxiality is measured at the area where ${\theta}$ is smaller than $60^{\circ}$, which excludes a side grooved area.

• Korean Journal of Clinical Pharmacy
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• v.27 no.1
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• pp.44-54
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• 2017

Background: Mental health issues such as stress and depression have been regarded as major social problems in Korea. We investigated the relationship between stress and depression with unmet medical needs (UMN). Methods: Using the nationwide database of 2010 Korea National Health and Nutritional Examination Survey (K-NHANES), subjects aged 19 years or above were selected (n=6,055). In the K-NHANES questionnaire, subjects were asked about their UMN experience, severity of stress, and perceived depression lasting at least 2 weeks over the past year. The effects of stress and depression on UMN were analyzed in 4 models established by adding predisposing, enabling and need factors in a step-wise fashion. The risks for UMN were also assessed according to the causes of UMN. Results: Individuals who felt stress 'very often' (odds ratio (OR) 3.28, 95% CI=2.23-4.86) and 'often' (OR 2.53, 95% CI=1.93-3.31) and who experienced depression (OR 1.68, 95% CI=1.35-2.10) reported significantly elevated UMN rates, and these effects were substantial especially for the individuals who had UMN due to economic constraint. Females, lower education level, lower income, unemployed status, and negative perceptions about health status were found to be additional risk factors for UMN. Conclusion: Our results confirmed the risks of stress and depression on UMN. It is strongly advisable to create initiatives to improve mental health, particularly stress and depression, and to fulfill individuals' medical utilization needs.

• Journal of Korean Society for Quality Management
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• v.18 no.2
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• pp.43-53
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• 1990

Mechanical components and structures are a major part of complex systems and the conseguences of their failure can be extremely costly. The ultimate goal of design engineers is to optimize these mechanical and structural design from the point of view of cost, reliability, weight, volume, maintainability and safety. An essential requirement of design optimization is to develop mathematical models for reliability at design stage. This paper is to minimize the cost of resources subject to the constraint that the reliability of the system must meet a specified level. The lagrange multiplier method is used to optimize the lognormal stress-lognormal strength problem. This optimization problem can be reduced to a search problem in one variable. A numerical example is presented to illustrate the optimization problem.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.40
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• pp.179-186
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• 1996

Previous researches on optimum ALT plans have shown how to find optimum allocation, lowest stress and sample size subject to minimizing the variance of mean life estimate. Those researches have assumed the censoring time constant. But under certain circumstances such assumptions may not be reasonable. In this paper the constraint on constant censoring time is relaxed, and censoring time is considered variable. If all other test parameters remain unvaried, the variance of the mean life estimate reciprocally increases of the censoring time. This idea in this paper extends to the optimum censoring time. Thus, this paper presents the optimal censoring time in such situations, and finds the optimal lowest stress and allocation based on that optimal censoring time.

• Proceedings of the KSPS conference
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• 2004.05a
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• pp.161-163
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• 2004

This study concerns the constraints of English Poetic Fixed Meter. In English poems, the metrical pattern doesn't always match the linguistic stress on the lines. These mismatches are found differently among the poets. For the lexical stress mismatched with the weak metrical position, ${\ast}W{\Rightarrow}$ Strength is established by the concept of the strong syllable. The peaked monosyllabic word mismatched with weak metrical position is divided according to which side of the boundary of a phonological domain it is adjacent to. In most poets, ${\ast}$Peak] is ranked higher than ${\ast}$[Peak. In Shakespeare, Adjacency Constraint is ranked higher than ${\ast}$Peak].

• Journal of Welding and Joining
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• v.19 no.5
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• pp.548-554
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• 2001

The restraint force is required an accurate measurement and analysis to protect weldment from residual stress. Also, this residual stress caused by clacks in weldments are often observed in the weldments of large size nozzles or radial tanks after welding. This paper is preformed on the study of evaluation of welding restraint forces using load cell with STS thin plate which are using pressure vessel steel in the industry field. As a result of this study, as the welding currents are higher and the welding speeds are more slowly, the magnitude of restraint force in process of the flat plate welding hows to be more large. Also, the temperature in process of melting is increasingly rising, then the restraint forces exhibit the compressive forces, whereas the restraint forces during cooling represent extensional force.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.11
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• pp.1685-1696
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• 2001

A novel indentation theory is proposed by examining the data from the incremental plasticity theory based finite element analyses. First the optimal data acquisition location is selected, where the strain gradient is the least and the effect of friction is negligible. This data acquisition point increases the strain range by a factor of five. Numerical regressions of obtained data exhibit that strain hardening exponent and yield strain are the two main parameters which govern the subindenter deformation characteristics. The new indentation theory successfully provides the stress-strain curve with an average error less than 5%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.4
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• pp.396-400
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• 2009

The demand of JIB crane to handle a container or a bulk in a vessel is increasingly because of the growth of the scale of trade through the sea. This deck crane such as JIB crane is required the weight reduction design because it is installed in the deck of a vessel due to the environment regulation. In this study first we carry out the structural analysis of JIB with respect to the luffing angle of it to calculate the maximum equivalent stress of JIB, and next the optimum design for the weight reduction design of JIB. The thickness in a cross section of JIB is adopted as the design variable, the weight of JIB as the objective function, and the von mises stress as the constraint condition for the optimum design of JIB using the ANSYS 10.0.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.12
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• pp.3003-3009
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• 2000

In this paper, we propose a new efficient hybrid-mixed C(sup)0 curved beam element with the optimal interpolation functions determined from numerical tests, which gives very accurate locking-free two-node curved beam element. In the element level, the stress parameters are eliminated from the stationary condition and the nodeless degrees of freedom are also removed by static condensation so that a standard six-by-six stiffness matrix is finally obtained. The numeri cal benchmark problems show that the element with cubic displacement functions and quadratic stress functions is the most efficient.