• 한국경영과학회지
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• 제23권3호
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• pp.185-207
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• 1998

This research investigates computer generated hybrid second-order model of two numerically based approaches to risk classification : discriminant analysis and neural networks. The hybrid second-order models are derived by rule induction using the ID3 and tested in the several different kinds of data. This new hybrid approach is designed to combine the high prediction accuracy and robustness of DA or NN with perspicuity of ID3. The hybrid model also eliminates the problem of contradictory inputs of ID3. After doing empirical test for the validity of hybrid model using small and medium companies' bankrupt data, hybrid model shows high perspicuity, high prediction accuracy for bankrupt, and simplicity for rules. The hybrid model also shows high performance regardless the type of data such as numeric data, non-numeric data, and combined data.

• Journal of Welding and Joining
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• 제19권4호
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• pp.399-405
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• 2001

A dynamic force balance model is proposed in this work as an extension of the previous static force balance model to predict metal transfer in arc welding. Dynamics of a pendant drop is modeled as the second order system, which consists of the mass, spring and damper. The spring constant of a spherical drop at equilibrium is derived in the closed-form equation, and the inertia force caused by drop vibration is included in the drop detaching condition. While the inertia force is small in the low current range, it becomes larger than the gravitational force with current increase. The inertia force reaches half of the electromagnetic force at transition current, and has considerable effects on drop detachment. The proposed dynamic force balance model predicts the detaching drop size more accurately than the static force balance model.

• Water Engineering Research
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• 제3권1호
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• pp.23-30
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• 2002

A numerical model for the solution of two-dimensional dam break problems using fractional step method is developed on unstructured grid. The model is based on second-order Weighted Averaged Flux(WAF) scheme with HLLC approximate Riemann solver. To control the nonphysical oscillations associated with second-order accuracy, TVD scheme with SUPERBEE limiter is used. The developed model is verified by comparing the computational solutions with analytic solutions in idealized test cases. Very good agreements have been achieved in the verifications.

• 천문학회지
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• 제28권2호
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• pp.223-243
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• 1995

We describe the implementation of a multi-dimensional numerical code to solve the equations for idea! magnetohydrodynamics (MHD) in cylindrical geometry. It is based on an explicit finite difference scheme on an Eulerian grid, called the Total Variation Diminishing (TVD) scheme, which is a second-order-accurate extension of the Roe-type upwind scheme. Multiple spatial dimensions are treated through a Strang-type operator splitting. Curvature and source terms are included in a way to insure the formal accuracy of the code to be second order. The constraint of a divergence-free magnetic field is enforced exactly by adding a correction, which involves solving a Poisson equation. The Fourier Analysis and Cyclic Reduction (FACR) method is employed to solve it. Results from a set of tests show that the code handles flows in cylindrical geometry successfully and resolves strong shocks within two to four computational cells. The advantages and limitations of the code are discussed.

• Communications for Statistical Applications and Methods
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• 제28권5호
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• pp.563-582
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• 2021

This paper deals with developing a general class of accelerated sequential procedures and obtaining the associated second-order approximations for the expected sample size and 'regret' (difference between the risks of the proposed accelerated sequential procedure and the optimum fixed sample size procedure) function. We establish that the estimation problems based on various lifetime distributions can be tackled with the help of the proposed class of accelerated sequential procedures. Extensive simulation analysis is presented in support of the accuracy of our proposed methodology using the Pareto distribution and a real data set on carbon fibers is also analyzed to demonstrate the practical utility. We also provide the brief details of some other inferential problems which can be seen as the applications of the proposed class of accelerated sequential procedures.

• Journal of applied mathematics & informatics
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• 제41권3호
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• pp.487-510
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• 2023

We propose a mathematical model which describes the frictional contact between a piezoelectric body and an electrically conductive foundation. The behavior of the material is described with a linearly electro-viscoelastic constitutive law with long term memory. The mechanical process is dynamic and the electrical conductivity coefficient depends on the total slip rate, the friction is modeled with Tresca's law which the friction bound depends on the total slip rate with taking into account the electrical conductivity of the foundation both. The main results of this paper concern the existence and uniqueness of the weak solution of the model; the proof is based on results for second order evolution variational inequalities with a time-dependent hemivariational inequality in Banach spaces.

• Computers and Concrete
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• 제17권5호
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• pp.579-596
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• 2016

This paper describes a method of the refined plastic hinge approach in the framework of the higher-order element formulation that can efficaciously evaluate the limit state capacity of a whole reinforced concrete structural system using least number of element(s), whereas the traditional design of a reinforced concrete structure (i.e. AS3600; Eurocode 2) is member-based approach. Hence, in regard to the material nonlinearities, the efficient and economical cross-section analysis is provided to evaluate the element section capacity of non-uniform and arbitrary concrete section subjected to the interaction effects, which is helpful to formulate the refined plastic hinge method. In regard to the geometric nonlinearities, this paper relies on the higher-order element formulation with element load effect. Eventually, the load redistribution can be considered and make full use of the strength reserved owing to the redundancy of an indeterminate structure. And it is particularly true for the performance-based design of a structure under the extreme loads, while the uncertainty of the extreme load is great that the true behaviour of a whole structural system is important for the economical design approach, which is great superiority over the conservative optimal strength of an individual and isolated member based on traditional design (i.e. AS3600; Eurocode 2).

• 한국정보시스템학회지:정보시스템연구
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• 제32권2호
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• pp.1-24
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• 2023

Purpose The aim of this study is to investigate how system quality, privacy concerns, and usefulness impact user satisfaction and word-of-mouth intention towards smart order services among Chinese consumers. The study also seeks to provide both theoretical and practical implications based on the findings. Design/methodology/approach This study conducted an empirical study on Chinese consumers through an online survey on 274 users of smart order service in China. To analyze the data, frequency analysis, reliability analysis, and confirmatory factor analysis were performed using SPSS 26.0 and AMOS 26.0 statistical programs, and structural equation model was used for hypothesis testing. Findings The study results are as follows. First, system quality was found to have a positive effect on usefulness and user satisfaction. Second, privacy concerns were found to have a positive effect on user satisfaction, but not on usefulness. Third, user satisfaction was found to have a positive effect on consumers' word-of-mouth intention of the smart order service. Finally, mediating effects were found between system quality and user satisfaction through usefulness, as well as between system quality, perceived privacy concern, and usefulness through user satisfaction.

• 대한가정학회지
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• 제34권4호
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• pp.86-101
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• 1996

The purpose of the study was to investigate whether there were differences between the Paternal child rearing Involvement and the Parental Satisfaction according to child's sex, father's age and the birth order of child. The subjects surveyed were 271 fathers 132 in their thiries and 139 in their forties who live in Kwang-ju. And the children considered are 128 boys and 143 girls. Among them, first-born children are 143 members, second-born are 103, and third-born are 25. Factor analysis, frequencies, mean, standard deviation, Cronbach's α, one way-ANOVA, Pearson's correlation coefficient, and step-wise regression are used for data-analysis. The main results were as follows : (1) There were some significant differences in the Paternal child rearing Involvement according to the child's sex, while there was no difference as related the father's age and the birth-order of child. (2) The were some significant differences in the father's Parental Satisfaction which is involved child's sex and the father's age, but there was no difference as to the birth-order of child. (3) There were some significant differences between the Paternal Child rearing Involvement and the Parental Satisfaction, and between its subfactor and the Parental Satisfaction, too. (4) The result of the step-wise regression, which analyses the Paternal child rearing Involvement and the background variables as to father's Parental Satisfaction, shows the Parent-child relationship variable (accounted for about32% of the general variation), spouse support, support of children, general satisfaction, and parent's role conflict at intensity in order. Of the above mentioned five fields, house-activities were the first factor in determining this order. And the personal interaction plays an important role in fulfilling general satisfaction and the support of children. The leisure-action factor was the second explanatory factor in establishing the parent-child relationship. Finally father's age was the fourth explanatory factor in assessing the parent-child relationship variable considering the background variables.

• Journal of Power Electronics
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• 제10권6호
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• pp.749-761
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• 2010

The switching frequency of a power device is a very important parameter in the design of a parallel active power filter (PAPF), but so far, very little discussion has been conducted on it in a quantitative manner in previous publications. In this paper, an extensive analysis on the effects of the switching frequency on the performance of a PAPF is made, and a specification of the switching frequency values with different compensation results is presented. A first-order inertia element and a second-order oscillation element are considered as approximate models of a PAPF, respectively. The compensation characteristic for each order of harmonic current is obtained at different switching frequencies. Then, the THDs of each model for the system loads of a rectifier with resistance and inductance loads are proposed. The compensation results of a PAPF controlled as a first-order inertia element are better than those of a PAPF controlled as a second-order oscillation element. With two types of system loads which are rectifier with resistance and inductance loads and rectifier with resistance, inductance and capacitance loads, the THDs of the source current after compensation are presented with different switching frequencies. The compensation characteristics for the most widely used digital control system are investigated. The situation with an analog control is the theoretical characteristic and it is the best situation. The compensation characteristic of the digital control is worse than the compensation characteristic of the theoretical characteristic. Based on these analyses, the specifications of compensation characteristics with different switching frequencies are quite straightforward. Finally, a practical design example is studied to verify the application.