• International Journal of Aeronautical and Space Sciences
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• v.18 no.1
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• pp.56-62
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• 2017

Because adhesively bonded joints are used in many structural systems, it is important to predict accurate adhesive strengths. Composite aircraft with many joints are easily exposed to low temperatures and high relative humidity. This paper presents a humidity aging effect on the adhesive strength of a composite single-lap joint (SLJ). The adhesive strength of the SLJ is predicted using a finite element analysis with a cohesive zone model (CZM) technique. The humidity aging effect is evaluated based on the adhesive strength and CZM parameters. A lap joint test is carried out on the composite SLJ specimens, which are exposed for four months of 100% R.H. at $25^{\circ}C$. The predicted strengths are in good agreement with experimental data, and the actual crack propagation is satisfactorily simulated using the local CZM technique.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.116-120
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• 2007

KOSEN(KOrean Scientists and Engineers' Network) started Blog servece to encourage users' knowledge sharing and interaction between users. Since blog opened in April of 2007, 251 blogs have been made. We could collect diverse information from technical knowledge to private hobbies. We could find our blog's limitations and weakness, too. We analyze blog patterns and suggest strategies for service activation in this paper.

• Phonetics and Speech Sciences
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• v.7 no.1
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• pp.107-116
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• 2015

The present experiment investigated the effect of word length on the length of f0 intervals for North Kyungsang children. In order to find out the lengths of the f0 intervals, the f0 values at the midpoints of vowels in words were measured. F0 estimates were computed as intervals consistent with the logarithmic scale corresponding to the number of syllables in the words. The results indicated that the mean f0 intervals in words of different lengths showed a significant difference for the HH in HH vs. HHL and the LH in LH vs. LLH for North Kyungsang children. Adult speakers from the North Kyungsang region significantly differed only within the HH in HH vs. HHL. Adult speakers made a noticeable contribution in this characteristic from the children. The result of the adult study was presented to confirm whether the children used a North Kyungsang dialect. With respect to individual speaker differences, the North Kyungsang children showed more or less consistent patterns in quantile-quantile plots for the HH vs. HHL, but for the HL vs. LHL and LH vs. LLH, there were more variations than for the HH vs. HHL. The individual speakers' variation was the largest for the HL vs. LHL and the smallest for HH vs. HHL. Considering these results, the effect of word length on f0 intervals tended to show pitch accent-type-specific characteristics in the process of prosodic acquisition.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.7
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• pp.642-650
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• 2008

In this paper, structural behavior of Gasket and GDL of a PEMFC stack is studied to improve the performance and to secure the safety. In the Gasket analysis Mooney-Rivlin strain energy function is used to consider hyperelasticity of load and displacement. The material properties is determined by testing specimens of the gasket at uni-axial and equi-biaxial mode and compared with finite element analysis results. By measuring a thickness change, the material property of GDL is determined. The pressure drop of a unit cell is measured along the channel for the clamping force. A cross sectional change of channel base on the experimental data is obtained experimentally and compare with FEM analysis results.

• Phonetics and Speech Sciences
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• v.7 no.2
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• pp.103-109
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• 2015

This paper describes the development of the Korean corpus of spontaneous speech, also called the Seoul corpus. The corpus contains the audio recording of the interview-style spontaneous speech from the 40 native speakers of Seoul Korean. The talkers are divided into four age groups; talkers in their teens, twenties, thirties and forties. Each age group has ten talkers, five males and five females. The method used to elicit and record the speech is described. The corpus containing around 220,000 phrasal words was phonemically labeled along with information on the boundaries for Korean phrasal words and utterances, which were additionally romanized. According to the test result of labeling consistency, the inter-labeler agreement on phoneme identification was 98.1% and the mean deviation on boundary placement was 9.04 msec. The corpus will be made available for free to the research community in March, 2015.

• Journal of Aerospace System Engineering
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• v.7 no.2
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• pp.1-7
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• 2013

Recently, there are a number of studies over dynamic analysis for minimizing vibration of flexible structures such as solar panel for agility of high-agility satellite. The traditional studies perform dynamic analysis of a solar panel assumed as rigid structure since the stiffness of solar panel is higher than the stiffness of solar panel's hinge spring. However, there are vibrations that have modes of bending and torsion when high-agility satellite rotate speedily. This vibrations result in delaying safety time of satellite or degrading image quality. This paper presents dynamic analysis's technique of satellites including the spring hinge of solar panel and flexible structural solar panel's effects described as the linear equation of motion using Lagrange's theorem, and verifies the validity of an established dynamic analysis's technique of satellites by comparing the finite element method. In addition high-agility satellite's dynamic characteristics of a torque profile are analyzed from the established dynamic analysis's technique of satellites.

• Journal of Korean Society on Water Environment
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• v.34 no.5
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• pp.487-493
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• 2018

Urban stormwater runoff is the one of the most extensive causes of deterioration of water quality in streams in urban areas. Especially, in the Suyeong River watershed, non-point sources from urban-residential areas are the most common cause of water pollution. Also, it has been ascertained that BOD and COD as indexes of organic matter, have limitation on management of Suyeong River's water quality. In this study, changes of organic matter properties of Suyeong River from inflow of non-point source during rainfall were investigated. Fractions of organic matters were analyzed using water samples collected at two sites (Suyeong River and Oncheon Stream) during a rain event. Variations of dissolved organic carbon (DOC) concentration by rainfall were similar to flow rate change in the river. Distribution of organic matter fraction according to change of rain duration revealed that while hydrophilic component increased at initial rainfall, the hydrophobic component was similar to change in dissolved organic carbon (DOC) concentration. Also, the relative proportion of hydrophilic components in organic matter in river water increased, due to rainfall. Results of biodegradation of organic matters revealed that decomposition rate of organic matters during rainfall was higher than that of during a non-rainfall event.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2004.05a
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• pp.62-62
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• 2004

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.936-938
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• 2017

In this paper, the progressive failure analysis of a bolted composite joint which is used in combustion tubes of projectiles and weapon systems is performed. Hashin's failure criterion is considered as fiber tensile failure mode, fiber compressive failure mode, matrix tensile failure mode, and matrix compressive failure mode for this analysis. And this criterion is used to make user subroutine, UMAT. Through the progressive failure analysis we predicted failure strength and compared failure strength with specimen test result.

• Journal of the Speleological Society of Korea
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• no.86
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• pp.16-24
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• 2008

Many researcher contended that the tourism types of modern society has changed to 'experience tourism' from 'seeing tourism' recently. Therefore attempts to add edutainment factors in the original tour program has been introduced in cases of tourism cave. As we can see the Hwaam-cave in Jungsun-gun, by preparing with various pavilions which are well-matched with tourism cave. So, the purpose of this study is to the presentations of the activation programs that having on characteristics of edutainment tourism resources for tourism cave. Thus, first of all for establishing of this study, we examined the characteristics and values as tourism resources of cave and then observed the roles and examples of edutainment tourism cave, finally suggested the activation programs that can be shaped for edutainment tourism of cave.