• Journal of Applied Reliability
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• v.11 no.3
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• pp.281-291
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• 2011

This paper presents an accelerated life test of booster pump for home water purifier. The failure analysis shows that decreased flux due to the plastic deformation of bypass spring adjusting pressure is the predominant failure mechanism. An accelerated life test is designed and implemented to estimate the lifetime of the booster pump. Temperature, water pressure and voltage are selected as accelerating variables through the technical review about failure mechanism. It is assumed that the lifetimes of booster pumps follow lognormal distribution and the combination model of temperature and non-thermal stresses holds. The life-stress relationship, acceleration factor, and $B_{10}$ life at design condition are estimated by analyzing the accelerated life test data.

• The Journal of the Acoustical Society of Korea
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• v.20 no.2
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• pp.21-26
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• 2001

An expectation-maximization (EM) based Bayesian adaptation method for the mean of noise is proposed for noise-robust speech recognition. In the algorithm, the on-line testing utterances are used for the unsupervised Bayesian adaptation and the prior distribution of the noise mean is estimated using the off-line training data. For the noisy speech modeling, the parallel model combination (PMC) method is employed. The proposed method has shown to be effective compared with the conventional PMC method for the speech recognition experiments in a car-noise condition.

• Journal of Information Processing Systems
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• v.13 no.4
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• pp.928-940
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• 2017

State-of-the-art speaker recognition systems may work better for the English language. However, if the same system is used for recognizing those who speak different languages, the systems may yield a poor performance. In this work, the decisions of a Gaussian mixture model-universal background model (GMM-UBM) and a learning vector quantization (LVQ) are combined to improve the recognition performance of a multilingual speaker identification system. The difference between these classifiers is in their modeling techniques. The former one is based on probabilistic approach and the latter one is based on the fine-tuning of neurons. Since the approaches are different, each modeling technique identifies different sets of speakers for the same database set. Therefore, the decisions of the classifiers may be used to improve the performance. In this study, multitaper mel-frequency cepstral coefficients (MFCCs) are used as the features and the monolingual and cross-lingual speaker identification studies are conducted using NIST-2003 and our own database. The experimental results show that the combined system improves the performance by nearly 10% compared with that of the individual classifier.

• Journal of Electrochemical Science and Technology
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• v.14 no.1
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• pp.38-50
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• 2023

Proton exchange membrane fuel cell (PEMFC) is a portable and clean power generation device. The structural arrangement of the flow field has a significant influence on the delivery efficiency of PEMFC. In this article, a new bionic flow channel is designed based on the inspiration of a spider shape. The branch channel width and branch corner are studied as the focus, and its simulation is carried out by the method of computational fluid dynamics (CFD). The results show that when channel width/rib width and corner of the branch are 1.5 and 130° , respectively, it is the best numerical combination and the cell comprehensive performance is excellent. The final model using this numerical combination is compared with the traditional flow channel model to verify the advancement of this scheme.

• Journal of Korea Multimedia Society
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• v.8 no.6
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• pp.836-843
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• 2005

The Wireless Internet services widely spread out with the developments of CDMA(Code Division Multiple Access) networks and wireless units. In contrast to the telecommunication network, WPAN (Wireless Personal Area Network) enables to transmit data and voice in personal area. Although WPAN technologies are commercially utilized, the combined services with COMA network are not so poplar up to now. Various services can be provided using the combination between COMA and WPAN. This paper presents the practical and united model between COMA and WPAN. Specially, the main focus of this research lies on the design of the Middle-ware system of a handset which could be managing both COMA and WPAN. This system used Bluethooth by WPAN. For the devices with the proposed WPAN Middle-ware, service areas of the COMA network can be expanded to WPAN, various services can be realized by the transmission of data and voice, and consequently, the user computing environment could be improved.

• Communications for Statistical Applications and Methods
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• v.19 no.6
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• pp.799-808
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• 2012

It is known that human disease and the economic traits of livestock are significantly affected by a gene combination effect rather than a single gene effect. Existing methods to study this gene combination effect have disadvantages such as heavy computing, cost and time; therefore, to overcome those drawbacks, the SNPHarvester was developed to find the main gene combinations. In this paper, we looked for gene combinations using an adjusted linear regression model. This research finds that superior gene combinations which are related to the quality of the Korean beef cattle among sets of SNPs using SNPHarvester. We also identify the superior genotypes using a decision tree that can enhance the various qualities of Korean beef among selected a SNP combination.

• Journal of Industrial Technology
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• v.14
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• pp.101-107
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• 1994

This study is to investigate harbor oscillation phenomenon according to combination of the wall structures by model experiment in a three dimensional wave basin. Six different types of wall combination were chosen through combination of erect wall, erect dissipation block, and sand beach, wave height at selected points in the harbor were measured by electronic wave gage. Test results show that the wall structure composed solely of erect walls showed generally highest harbor oscillation. Since natural beach shows lower reflection than erect dissipation block do, we thought it would be more efficient to use natural beach for improved harbor oscillation. The result showed, however, that the erect dissipation block are more efficient than natural beach to attain less harbor oscillation. The reason seens that the erect dissipation blocks have better capability to control breaking wave on the surface of the structure.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.11
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• pp.957-965
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• 2013

This paper deals with analytical methods for low frequency and high frequency brake squeal noise on brake-rear caliper. In order to improve low frequency and high frequency squeal noise, we take survey caliper bracket shape parameters and housing shape parameters. Besides, using the combination of bracket and housing parameter were surveyed. Thus, using the combination of bracket Alt_05 and housing Alt_45 specifications, instability analysis and brake dynamo test were carried out. Based upon the two models, low and high frequency squeal noise of base model were improved. But, for 6.0 kHz frequency noise, which is not improved, it needs to additionally study on instability analysis and combination of the other brake components.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.69-70
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• 2022

The domestic process planning generally relies on calculations based on the construction-standard-production-rate. This method requires trial and error practice during the construction phase to deduce the optimized equipment combination for time and cost. Trial and error during construction can lead to cost overruns and schedule delays. Accordingly, this paper suggests an advanced method for establishing a productivity database based on combinations of equipment and also considering site conditions in order to reduce the timely effort for deducing the optimized equipment combination. For this purpose DES (Discrete Event Simulation) model was developed based on the information provided in the construction-standard-production-rate.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.342-343
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• 2021

The color combination effect is greatly influenced by individual experiences and preferences. In this paper, we will look at the associative words of color. And the combination of color and language is accompanied by a symbol of human experience. In this way, the psychological treatment effect resulting from the color combination effect is also examined.