• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.7
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• pp.665-673
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• 2011

Simplified formulae for axial and bending natural frequencies of a bellows are developed using an equivalent thin-walled pipe model. The axial and bending stiffness of bellows is determined using lumped transfer matrix method. Transfer matrix method which includes the rotary inertia is used to calculate the natural frequencies for axial and lateral vibration. The result from the simplified formula are verified by those from as experiment result and a finite element analysis. This comparisons show good agreement with the each other.

• Bulletin of the Korean Chemical Society
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• v.7 no.4
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• pp.299-304
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• 1986

Master formulas for overlap integrals and the dipole moments involving |4p > atomic orbitals have been derived by the expansion method for spherical harmonics. The radial integrals for the hyperfine interaction have also been derived for |4p > atomic orbitals. The calculated values of the overlap integrals and dipole moment matrix elements by the expansion method for spherical harmonics for a hypothetical NO molecule are exactly in agreement with those of Mulliken's method. The radial integrals for the hyperfine interaction may be used to calculate the chemical shift for |4p > atomic orbitals.

• Journal of Korean Society of Forest Science
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• v.99 no.5
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• pp.693-697
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• 2010

Biomass expansion factors that convert the timber volume (or dry weight) to biomass are used to estimate the forest biomass and account for the carbon budget on a national and regional scale. This study estimated the biomass conversion and expansion factors (BCEF), root to shoot ratio (R), biomass expansion factors (BEF) and ecosystem biomass expansion factor (EBEF) of Korean pine (Pinus koraiensis) forests based on direct field surveys and publications in Korea. The mean BCEF, BEF, and R was 0.6438 Mg $m^{-3}$ (n = 7, SD = 0.1286), 1.6380 (n = 27, SD = 0.1830), and 0.2653 (n = 14, SD = 0.0698), respectively. The mean EBEF, which is a simple method for estimating the understory biomass in Korean pine forest ecosystems, was 1.0218 (n = 6, SD = 0.0090). The values of the biomass expansion factors in this study estimated the Korean pine forest biomass with more precision than the default values given by the IPCC (2003, 2006).

• The korean journal of orthodontics
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• v.34 no.1 s.102
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• pp.23-31
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• 2004

As a research method that weighs and combines evidence, meta analysis produces evidence that is more powerful than the original studies. The purpose of this study was to compare the jntercanine/intermolar expansion and rapid/slow expansion in the maxillary expansion treatment using meta analysis. Medline was searched from 1979 to 2000 for all studies examining the stability of transverse expansion of the human maxilla, and 388 articles were found. Then these articles were reduced to 7 based on the defined inclusion and exclusion criteria, and a cumulative Meta evaluation score was computed for each study. The results were as follows; 1. The mean expansion in intermolar width was 6.0mm. of the 6.0mm, 4.8mm was retained and $20.0\%(1.2mm)$ was relapsed while wearing retainers. 2. In intercanines width, the mean expansion was 3.7mm. of the 3.7mm, 2.6mm was retained and $29.7\%(1.1mm)$ was relapsed while wearing retainers. 3. The differences In the amount of expansion and relapse between rapid expansion group and slow expansion group were less than $6\%(0.1-0.3mm)$. But, there might be differences in the skeletal/dental exapnsion ratios according to the expansion method.

• ETRI Journal
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• v.39 no.4
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• pp.455-466
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• 2017

This study focuses on a method for sequential data augmentation in order to alleviate data sparseness problems. Specifically, we present corpus expansion techniques for enhancing the coverage of a language model. Recent recurrent neural network studies show that a seq2seq model can be applied for addressing language generation issues; it has the ability to generate new sentences from given input sentences. We present a method of corpus expansion using a sentence-chain based seq2seq model. For training the seq2seq model, sentence chains are used as triples. The first two sentences in a triple are used for the encoder of the seq2seq model, while the last sentence becomes a target sequence for the decoder. Using only internal resources, evaluation results show an improvement of approximately 7.6% relative perplexity over a baseline language model of Korean text. Additionally, from a comparison with a previous study, the sentence chain approach reduces the size of the training data by 38.4% while generating 1.4-times the number of n-grams with superior performance for English text.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.4
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• pp.723-729
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• 2013

The contraction and expansion noise of a refrigerator are investigated, and some effective methods are proposed to reduce the level and occurrence frequency of noise. First, the noise of a refrigerator is measured to estimate the frequency spectrum and occurrence frequency of noise. Second, a sound visualization was conducted using an acoustic camera to determine the location of the noise source. From the results, it was observed that the internal part mainly producing noise was the third shelf in the freezer room. A method to estimate the acceleration on the location of the noise source is introduced to analyze the contraction and expansion noise precisely and accommodate experimental convenience. Noise reduction methods such as the replacement of the existing shelf with glass shelves, adoption of rail slides, and increase of roughness on the contact surface of the shelf are proposed and tested.

• Journal of Korea Multimedia Society
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• v.20 no.10
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• pp.1689-1696
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• 2017

The purpose of this study is to contribute to the development of a source of cultural contents by proposing extension possibility of cultural contents based on an original source. To this end, this article examined an aspect of Sherlock Holmes contents based on the novel "Sherlock Holmes" published in 1887. It has been produced as 217 different contents from 1899 to 2017 after publishing the novel Sherlock Holmes, and consequently, it has become the best material for the study of the expansion of contents. As a research method, we examined the concept of Transmedia with the change of media environment. Next, we examined the production method of "Sherlock Holmes" contents, analyzed the transformation factors according to each media, and presented the expansion of contents through "Sherlock Holmes" contents.

• The Journal of the Korea Contents Association
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• v.4 no.1
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• pp.76-82
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• 2004

In this paper, we used query evaluation method through thesaurus for retrieving Components having concept relation with any classes in a query. Queries are presented in boolean and expanded by similar table. Query expansion by thesaurus is the solution of the term mismatching and it enhanced precision and recall of the components retrieval. For efficiency evaluation of query expansion, we defined most critical value through a simulation and compared precision and recall each other.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.895-904
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• 2015

This paper presents a probabilistic approach of reliability evaluation and economic assessment for solving transmission network expansion planning problems. Three methods are proposed for TNEP, which are reorganizing the existing power system focused on the buses of interest, selecting candidates using modified system operating state method with healthy, marginal and at-risk states, and finally choosing the optimal alternative using cost-optimization method. TNEP candidates can be selected based on the state reliability such as sufficient and insufficient indices, as proposed in this paper. The process of economic assessment involves the costs of construction, maintenance and operation, congestion, and outage. The case studies are carried out with modified IEEE-24 bus system and Jeju island power system expansion plan in Korea, to verify the proposed methodology.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.5
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• pp.1373-1387
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• 2012

Contextual advertising is an important revenue source for major service providers on the Web. Ads classification is one of main tasks in contextual advertising, and it is used to retrieve semantically relevant ads with respect to the content of web pages. However, it is difficult for traditional text classification methods to achieve satisfactory performance in ads classification due to scarce term features in ads. In this paper, we propose a novel ads classification method that handles the lack of term features for classifying ads with short text. The proposed method utilizes a vocabulary expansion technique using semantic associations among terms learned from large-scale search query logs. The evaluation results show that our methodology achieves 4.0% ~ 9.7% improvements in terms of the hierarchical f-measure over the baseline classifiers without vocabulary expansion.