• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.3
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• pp.323-334
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• 2008

According to the delivery condition, the breakage of a product occurs when it is delivered to the customers. Therefore product's makers evaluate the durability under the delivery process by accelerated life testing. In order to conduct this accelerated life testing accurately, it is very important to identify the acceleration-factor exactly between on-road and accelerated life test condition. In this paper, the acceleration-factor is identified by applying linear damage summation law, rain-flow cycle counting and Dirlik theory under the conditions of the random vibration. And approximated FEM model of the connecting-pipe to the compressor is developed for fatigue analysis. This model is finally verified by comparing the experiment results to the numerical analysis results.

• Journal of Korean Library and Information Science Society
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• v.43 no.4
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• pp.183-199
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• 2012

This study is to develop an operating model of Conspectus for online resources by using mechanistic quality factor. Based on some empirical statistics about resource use behaviour such as collection rate, use rate, search rate, the mechanistic quality factor was calculated and applied to each subject by adjusting its acquisition level of Conspectus. according to the result of this study, Acqusition levels of the subject such as technical science which shows higher in use rate, and those such as history and social science which show higher in search rate, should be adjusted to a higher acquisition level, and those of others to the same or a lower level.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1369-1379
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• 2018

In this paper, a model predictive torque control (MPTC) without the use of a weighting factor for surface mounted permanent-magnet synchronous machine (SPMSM) drive systems is presented. Firstly, the desired voltage vector is predicted in real time according to the principles of deadbeat torque and flux control. Then the sector of this desired voltage vector is determined. The complete enumeration for testing all of the feasible voltage vectors is avoided by testing only the candidate vectors contained in the sector. This means that only two voltage vectors in the sector need to be tested for selecting the optimal voltage vector in each control period. Thus, the calculation time can be reduced when compared with the conventional enumeration method. On the other hand, a novel cost function that only includes the dq-axis voltage errors between the desired voltage and candidate voltage is designed to eliminate the weighting factor used in the conventional MPTC. Thus, the control complexity caused by the tuning of the weighting factor is effectively decreased when compared with the conventional MPTC. Simulation and experimental investigation have been carried out to verify the proposed method.

• Structural Engineering and Mechanics
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• v.46 no.3
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• pp.353-370
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• 2013

This paper presents a new method to study the impact factor of an old bridge based on the model updating technique. Using the genetic algorithm (GA) by minimizing an objective function of the residuals between the measured and predicted responses, the bridge and vehicle coupled vibration models were updated. Based on the displacement relationship and the interaction force relationship at the contact patches, the vehicle-bridge coupled system can be established by combining the equations of motion of both the bridge and vehicles. The simulated results show that the present method can simulate precisely the response of the tested bridge; compared with the other bridge codes, the impact factor specified by the bridge code of AASHTO (LRFD) is the most conservative one, and the value of Chinese highway bridge design code (CHBDC) is the lowest; for the large majority of old bridges whose road surface conditions have deteriorated, calculating the impact factor with the bridge codes cannot ensure the reliable results.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.3
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• pp.140-148
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• 2009

Capillary tubes are widely used as expansion device in small refrigeration systems. The refrigerant flowing in the capillary tube experiences frictional and accelerational head losses and flashing simultaneously. In this paper flow characteristics of adiabatic capillary tubes were simulated with various friction factor models, two-phase viscosity models, and two-phase frictional multiplier models. The predicted pressure distribution and mass flow rate are compared with experimental data reported in literature. It is confirmed that the predicting accuracy with homogeneous model can be improved by employing suitable correlations of friction factor, two-phase viscosity and two-phase frictional multiplier.

• The Research Journal of the Costume Culture
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• v.23 no.5
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• pp.876-893
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• 2015

The purpose of this study is to identify the influences of psychological variables and fashion-related psychological variables on purchasing fashion items on the Internet. Boredom proneness and public self-consciousness were selected as psychological variables, and dressing style was selected as a fashion-related psychological variable. It was hypothesized that boredom proneness and public self-consciousness not only influence the purchasing frequency of fashion items on the Internet directly, but also indirectly through dressing style. Data were gathered by surveying university students in Seoul using convenience sampling. Two hundred and eighty-six questionnaires were used in the statistical analysis. SPSS was used for exploratory factor analysis, and AMOS was used for hypothesized relationship testing. The factor analysis of boredom proneness revealed five dimensions, "helplessness," "affective response," "lack of internal stimulation," "lack of external stimulation," and "perception of time." The factor analysis of public self-consciousness revealed two dimensions, "appearance-consciousness" and "style-consciousness," and the factor analysis of dressing style revealed one dimension. The overall fit of the hypothesized model suggests that the model fits the data well. The hypothesized relationship test proved that boredom proneness and public self-consciousness influence the purchasing frequency of fashion items on the Internet indirectly through dressing style. The results implicate effective strategies for Internet shopping malls and suggestions for future study.

• Tribology and Lubricants
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• v.17 no.3
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• pp.236-243
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• 2001

In this study, flow factors are evaluated in terms of kurtosis using random rough surface generated numerically. As h/$\sigma$become large ø$\sub$x/, ø$\sub$y/, ø$\sub$fp/, approach to 1 and ø$\sub$s/, ø$\sub$fs/ to 0 asymptotically regardless of kurtosis. ø$\sub$x/, ø$\sub$y/, ø$\sub$fp/ increase with increasing kurtosis in the mixed lubrication regime. ø$\sub$s/, ø$\sub$fs/ is associated with an additional flow transport due to the combined effect of sliding and roughness. As h/$\sigma$ decreases ø$\sub$s/, ø$\sub$fs/ increase up to a certain point, and then decrease toward zero. This behavior can be attributed to the increasing number of contacts in the mixed lubrication regime. ø$\sub$x/ in the presence of elastic deformation on the surface is larger than ø$\sub$x/ in the absence of it because local film thickness(h$\sub$T/) increases by elastic deformation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.2
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• pp.55-65
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• 2009

Purpose: We determined the therapeutic effects of blockade of epidermal growth factor(EGF) and vascular endothelial growth factor(VEGF) receptor tyrosine kinases on the growth of oral squamous cell carcinoma(OSCC) xenografted in athymic nude mice. Experimental Design: We investigated the in vivo antitumor effects of a tyrosine kinase inhibitor for EGFR and VEGFR-2, AEE788 in a mouth floor(orthotopic) tumor model. Nude mice with orthotopic tumors were randomized to receive AEE788, paclitaxel, a combination of AEE788 and paclitaxel, or control. Antitumor mechanisms of AEE788 were determined by immunohistochemical/immunofluorescent and apoptosis assays. Results: Tumors of mice treated with AEE788 demonstrated down-regulation of phosphorylated EGFR, phosphorylated VEGFR and their downstream mediators(pMAPK and pAkt), decreased proliferative index, decreased microvessel density(MVD). As a result, growth of the primary tumor and nodal metastatic potentials were inhibited by AEE788. Conclusion: These data show that EGFR and VEGFR can be molecular targets for the treatment of OSCC.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.2
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• pp.185-191
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• 2008

Optimal damping layout of the constrained viscoelastic damping layer on beam is identified with temperatures by using a gradient-based numerical search algorithm. An optimal design problem is defined in order to determine the constrained damping layer configuration. A finite element formulation is introduced to model the constrained layer damping beam. The four-parameter fractional derivative model and the Arrhenius shift factor are used to describe dynamic characteristics of viscoelastic material with respect to frequency and temperature. Frequency-dependent complex-valued eigenvalue problems are solved by using a simple re-substitution algorithm in order to obtain the loss factor of each mode and responses of the structure. The results of the numerical example show that the proposed method can reduce frequency responses of beam at peaks only by reconfiguring the layout of constrained damping layer within a limited weight constraint.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.1
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• pp.58-70
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• 1989

The paper compared the Bishop methed to the Fellenius method in the analysis of slope stability. Laboratory model test was carried out in the case of seepage flow considered. The results obtained from this study were summarized as follows; 1. The slice pieces of 10 were enough to analysis the slope stability. 2. The safety factor. by the Fellenius method was lower than the Bishop method by the 96 to 97% in the case of no seepage flow and by the 95 to 96% in the case of seepage flow considered. 3. Besides the parameter of soil and slope, the safety factor of slope was influenced by the height of slope. This phenomena was distinct in the height of height less than 10 meters. 4. In the case of clay, there was no difference in the safety factor of slope between Fellenius and Bishop rnethod. The safety factors of slope with the seepage flow considered were lower than those with no see-page flow. 5. The influence of cohesion on the safety factor was more significant in the Bishop method than in the Fellenius method. 6. The slope failure of model test of A and B soil samples with high permeability coefficient was taken place slightly in vicinity of toe by the concentration of stress and gradually increased 7. Under condition of same slope height, the shapper the slope, the shorter the radius and the center of critical circle appered downward and finally failure of slope occured inside the slope.