• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.1
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• pp.47-55
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• 2017

This study evaluated critical factors influencing the success of regenerative endodontic treatment for necrotic immature permanent teeth. The study enrolled patients who had regenerative endodontic treatment in a necrotic immature permanent tooth through 1-year follow-up. Possible explanatory variables related to the success rates for 46 teeth were age, gender, dental stage at the initial appointment, etiology, treatment information, and clinical and radiographic outcomes. The dental stage at the time of regenerative endodontic treatment did not influence the success rate. The success rate was significantly related to the etiology of the necrotic immature tooth. The success rate according to etiology decreased in the following order: dens evaginatus, caries, and trauma. There was also a significant difference according to the type of antimicrobial. The success rate was influenced by appropriate disinfection of the root canal system, provision of a scaffold, and coronal sealing. Above all, careful case selection is necessary for treating a necrotic immature permanent tooth, especially in cases of trauma.

• Current Research on Agriculture and Life Sciences
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• v.7
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• pp.175-184
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• 1989

Kinetics of ascorbic acid and browning that may use on the optimization of food dehydration were evaluated. Banana was chosen for this as the representative test material. We have described the destruction of ascorbic acid and browning as first and zero order reactions. The temperature dependence between two reactions were conducted with Arrhenius equation. Finally we have operated SPSS computer programs reapeatedly that we found very dose value of the parameter between result of ascorbic acid and browning. The attained Kinetic models were well prepared for the value of result experiments and the models may use on optimization for dehydration progress. Destruction rate of ascorbic acid and browning rate were low at initiation of progress, increased to show maximum at the low moisture on mid-progress and then decreased gradually. Freeze drying showed the most constant quality of product in this case.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.6
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• pp.322-332
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• 2014

This paper proposes a robust lane detection algorithm for non-flat roads by combining a piecewise linear model and dynamic programming. Compared with other lane models, the piecewise linear model can represent 3D shapes of roads from the scenes acquired by monocular camera since it can form a curved surface through a set of planar road. To represent the real road, the planar roads are created by various angles and positions at each section. And dynamic programming determines an optimal combination of planar roads based on lane properties. Experiment results demonstrate the robustness of proposed algorithm against non-flat road, curved road, and camera vibration.

• Korean Journal of Environmental Biology
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• v.19 no.2
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• pp.153-157
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• 2001

The relationship between SPM (Suspended Particulate Matter) and fungal spore in the air was investigated in Seosan, a rural county of Korea, in spring of 2000. SPM concentrations in the air were $199.8\mu{g}\;m^{-3}$, in the 1st Yellow Sand Period (March, 23-24), $249.4\mu{g}\;m^{-3}$ in the 2nd Yellow Sand Period (April, 7-9) and $98.9\mu{g}\;m^{-3}$ in the Non Yellow Sand Period (May, 12-16), respectively. Although there was somewhat difference in total SPM concentration between the two Yellow Sand Periods, majority of the total SPM were composed of $5\mu{m}$ sized coarse particles over the two periods. However, fine particles sized about $1\mu{m}$and coarse particles sized about $5-6\mu{m}$ ultimately showed peaks, which was within typical bimodal pattern at the graph of SPM size distribution in the Non Yellow Sand Period. Four mold genera grown from airborne fungal spores were finally identified in full-grown colonies at the SPM samples during the Yellow Sand Periods. These genera were Fusarium, Aspergillus, Penicillium and Basipetospora.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.2
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• pp.101-109
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• 2002

The aluminum honeycomb sandwich panel (AHSP) structure not only have high flexural rigidity and strength per density but also excellence in vibration and noise properties. The AHSP structure are very useful for railway, airplane and high speed ship which need lighter-weighted and more strengthened elements. In this paper, from comparison the AHSP with the equivalent aluminum single plate (EASP) structure on the result of analysis, it was shown that the AHSP is S times lighter weight to the same stiffness than the EASP. And the AHSP structure have high bending rigidity and small shear rigidity in the direction of the thickness. Also, to the characteristics of vibration for the AHSP and EASP, which the stiffness is larger than the EASP, are higher than EASP.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.9
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• pp.46-54
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• 2003

The purpose of this study is to analyze the phenomena of the thermally-induced vibration for the flexible space structure due to abrupt change of radiation heating circumstance using the numerical analyze and experiment test. In order to verify this structure, numerical approaches on the simplified flexible tube were compared with experimental test results at the ground experimental facility. In this analyze, it was found that the thermal deformation occurs firstly due to fast radiation heating of flexible structure and then the thermally-induced vibration would be induced due to small periodic change of temperature. According to comparison of numerical and experimental results, in case of no tip mass, the first mode vibration by the numerical analyze was a.78Hz same as that of the experimental result. However in case of increase tip-masses of 8g, 16g, 50g and 100g, the first modes vibration theoretical analyze were 1.75Hz, I.3Hz, a.87Hz and 0.73Hz, in decrease trend respectively and those by experimental test were 2.34Hz, 1.5Hz, 0.78Hz and 0.78Hz in decrease trend respectively. Although using the simpled equation for the estimation, the estimation results were similar to experimental results.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.345-352
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• 2007

오늘날 휴대폰은 20~30대의 젊은 사용자 층뿐 아니라, 고령사용자 및 아동사용자들로 확대되면서 다양한 사용자층을 포함하게 되었다. 이렇게 사용자층은 다양해지고 있으나, 휴대폰 제조사들은 다양한 사용자 계층의 인지능력과 요구사항을 반영하진 못한 채, 20~30대의 젊은 주 사용자 층을 기준으로 디자인하고 있다. 특히, 하드웨어적인 디자인 측면에서는 다각화가 이루어지고 있는 편이나, 소프트웨어 측면에서의 시도는 거의 미비하다. 따라서, 본 연구에서는 다양한 사용자 계층에 따른 유동적 인지능력 및 요구사항, 감성에 맞는 맞춤형 My메뉴(Menu)를 설정할 수 있는 휴대폰 UI 디자인을 제안하고자 한다. 특히, 주 사용자 층과는 다른 사용패턴을 보이는 어린이들을 위한 개인화된 My메뉴를 설정하는 인터랙션 UI 디자인 개발하여 제안하였다. 본 논문은 먼저, 문헌과 사례분석으로 통해 기존 휴대폰 제조사와 서비스 사업자들의 메뉴 개인화를 위한 다양한 시도를 조사하였다. 또한, 어린이들의 사용 패턴과 메뉴의 사용 빈도 등을 파악하기 위하여 사용자 조사 방법을 두가지 방법으로 진행하였다. 우선 2006년 7월말부터 8월 10일까지 2주에 걸쳐, 만 9세~12세의 초등학교 아동사용자 남여 10명을 대상으로 휴대폰 사용의 전반적인 특성과 사용행태을 파악하고, 환경설정 및 주 사용메뉴를 조사하기 위한 심층인터뷰를 시행하였다. 그리고 1차 인터뷰 내용을 바탕으로 설문지를 작성하였다. 이번 설문에서는 주 사용메뉴가 무엇이며 사용빈도는 어느 정도 되는지 선호하는 메뉴형식과 용어의 어려움은 없었는지를 파악했다. 또한 사용자가 자주 사용하는 메뉴를 대기화면에 가져다 놓고 싶은지를 물어 직접적인 휴대폰 대기화면의 사용여부를 파악하였다. 2006년 12월 일주일동안, 1차 인터뷰의 아동사용자와 동일한 연령대의 아동사용자 남여 총46명을 대상으로 설문조사를 실시하여 더욱 정량화된 데이터를 얻을 수 있었다. 이를 바탕으로 사용자 연령과 성별에 따라 기본 디폴트 My메뉴(Menu)를 제공하는 방법, My메뉴의 항목과 우선순위, 테마를 설정하여 개인화하는 UI 디자인을 도출하였다. 본 연구는 아동사용자를 대상으로 휴대폰의 소프트웨어 UI 중 메뉴를 사용자 맞춤형으로 설정할 수 있는 방법과 인터랙션을 디자인하여 제시하였다. 이러한 소프트웨어적인 UI 개인화 시도는 다양한 사용자 계층의 요구사항을 반영하는 보다 효율적인 방법으로써 사용자 만족과 사용성을 높이는 효과를 가져올 수 있을 것이다.

• Journal of Broadcast Engineering
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• v.17 no.5
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• pp.725-733
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• 2012

MPEG and VCEG have constituted a collaboration team called JCT-VC(Joint Collaborative Team on Video Coding) and have been developing the HEVC(High Efficiency Video Coding) standard. The next generation video coding standard HEVC shows higher compression rate compared with the H.264/AVC standard, but the encoder computational complexity of the HEVC encoder is significantly high. In order to reduce this computational complexity in the HEVC encoder, a fast prediction unit decision is proposed. The proposed fast prediction unit decision method reduces the encoder complexity by skipping the remaining prediction units if the current prediction unit does not have any non-zero quantized transform coefficient. The proposed method reduces the encoder computational complexity by 50.3% comparing with HM6.0 but it maintains the same level of coding efficiency.

• Education of Primary School Mathematics
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• v.15 no.3
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• pp.177-187
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• 2012

The purpose of this study was to analysis the gender differences in the academic achievement and the difference of academic achievement by the residential area in elementary school. Common phenomenon was observed in the result of the differences between male and female students' academic achievement and the ratio of achievement level. Female students' score was higher in 3rd grade elementary school but in 4th and 5the grade this phenomenon was gradually weakened. The following are the results of analysis of elementary school students' mathematics academic achievement in three areas(big city, small city and rural area). In the result was proved that the problem of the gap between the urban and rural areas has continued in the 21st century.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.751-756
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• 2010

Ultrasonic nonlinearity is very sensitive to changes in material properties. This paper describes the study of the correlation between heat treatment and ultrasonic nonlinearity by taking nonlinear factors into consideration. A modified formula was proposed for ultrasonic velocity. This formula indicated that the changes occurring in nonlinearity during heat treatments cause changes in the ultrasonic velocity. The experimental results show that the relative nonlinearity parameters calculated from the modified ultrasonic velocities and the ratio of amplitudes of the second harmonic and fundamental wave are in good agreement. The experimental results prove that heat treatment can result in changes in material nonlinearity. Moreover, the relative nonlinearity parameter calculated from the modified velocity formula is has a large value. Since this parameter has high sensitivity to changes in nonlinearity, it can be used to represent the relative nonlinearity change calculated in this study by using the modified formula for ultrasonic velocity.