• Polymer(Korea)
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• v.35 no.6
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• pp.543-547
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• 2011

A study has been done to enhance the mechanical properties and processability of electrically conductive polyaniline(PANI) without the polymer's structural alternation. Functionalized acid doped PANI (PANI-DBSA) was prepared by an emulsion polymerization, and dodecylbenzenesulfonic acid (DBSA) played both roles of surfactant and dopant. Also, PANI-DBSA was solution cast blended with high impact polystyrene (HIPS) to produce PANI-DBSA/HIPS blend film. The structure and electrical properties of the conducting polymer blends were observed through UV-vis and FTIR/ATR spectroscopy. A study of the blend was carried by focusing on observation of mechanical and electrical properties based on dispersibility and changes in polymer morphology. The conductivity of the blends was increased by increasing the content of PANI-DBSA, and the sudden increase of conductivity to $3.5{\times}10^{-4}$ S/cm was observed even under a low content of 9 wt%. There was a strong association of continuous network formation with percolation and conductivity in the conducting polymer blends.

• The Journal of the Acoustical Society of Korea
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• v.40 no.5
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• pp.466-472
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• 2021

Speaker Change Detection (SCD) refers to finding the moment when the main speaker changes from one person to the next in a speech conversation. In speaker change detection, difficulties arise due to overlapping speakers, inaccuracy in the information labeling, and data imbalance. To solve these problems, TIMIT corpus widely used in speech recognition have been concatenated artificially to obtain a sufficient amount of training data, and the detection of changing speaker has performed after identifying overlapping speakers. In this paper, we propose an speaker change detection system that considers the speaker overlapping. We evaluated and verified the performance using various approaches. As a result, a detection system similar to the X-Vector structure was proposed to remove the speaker overlapping region, while the Bi-LSTM method was selected to model the speaker change system. The experimental results show a relative performance improvement of 4.6 % and 13.8 % respectively, compared to the baseline system. Additionally, we determined that a robust speaker change detection system can be built by conducting related studies based on the experimental results, taking into consideration text and speaker information.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.2
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• pp.117-126
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• 2019

Legacy study for detecting arrhythmia have mostly used nonlinear method to increase classification accuracy. Most methods are complex to process and manipulate data and have difficulties in classifying various arrhythmias. Therefore it is necessary to classify various arrhythmia based on short-term data. In this study, we propose a feature extraction based on auto regressive modeling and an premature contraction arrhythmia classification method using SVM., For this purpose, the R-wave is detected in the ECG signal from which noise has been removed, QRS and RR interval segment is modelled. Also, we classified Normal, PVC, PAC through SVM in realtime by extracting four optimal segment length and AR order. The detection and classification rate of R wave and PVC is evaluated through MIT-BIH arrhythmia database. The performance results indicate the average of 99.77% in R wave detection and 99.23%, 97.28%, 96.62% in Normal, PVC, PAC classification.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.2
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• pp.63-68
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• 2021

This study was focused to investigate the effect of NbC-coated crucible on the quality of the SiC crystals. Then, the different properties between SiC crystals grown in a conventional graphite crucible and NbC-coated crucible were systematically compared. SiC crystals were grown using the Physical Vapor Transport (PVT) method at a temperature of 2300℃ and a pressure of 5 Torr in Ar atmosphere. After grinding and polishing, the polytype of the grown SiC crystal was analyzed using Raman spectroscopy, and crystallinity was confirmed by HR-XRD. Furthermore, the defect density and the concentration of impurities were analyzed by an optical microscope and a SIMS, respectively.

• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.248-255
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• 2020

In this study, we analyze the current state of domestic food waste (FW) recycling and propose a management plan for greenhouse gas (GHG) emissions. First, the composting potential of the GW demonstrates considerable promise. In particular, the GW (phytoplankton, periphyton, macrophyte, etc.) as a third-generation biomass shows strong performance as a functional additive that mitigates the disadvantages associated with composting FW and improves the quality of the final composted product. Alternatively, the final product (e.g., soil ameliorant) can be used to produce bio-filters that are effective pollutant buffers, with high applicability for green infrastructure. The proposed ecological approaches create new opportunities for FW as a resource for the reduction of GHG emissions, and are expected to contribute to the establishment of effective net-zero carbon systems in the future.

• Journal of the Korean institute of surface engineering
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• v.54 no.1
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• pp.25-29
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• 2021

The fabrication of nanopore membrane by deposition of Al2O3 film using electron-beam evaporation, which is fast, cost-effective, and negligible dependency on substance material, is investigated for potential applications in water purification and sensors. The decreased nanopore diameter owing to increased wall thickness is observed when Al2O3 film is deposited on anodic aluminum oxide membrane at higher deposition rate, although the evaporation process is generally known to induce a directional film deposition leading to the negligible change of pore diameter and wall thickness. This behavior can be attributed to the collision of evaporated Al2O3 particles by the decreased mean free path at higher deposition rate condition, resulting in the accumulation of Al2O3 materials on both the surface and the edge of the wall. The reduction of nanopore diameter by Al2O3 film deposition can be applied to the nanopore membrane fabrication with sub-100 nm pore diameter.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.75-75
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• 2020

여주(Momordica charantia L.)는 인도 동부와 남중국 등 열대 아시아 지역이 원산지로, 열대 및 아열대를 비롯하여 온대 지역까지 널리 재배되며, 열매를 식용으로 하여 주로 채소로 재배되고 있는데, 쓴맛 때문에 '쓴오이' 라고도 부르지만 당뇨와 고혈압 등 성인병과 장 기능 개선 성분을 함유하고 있다고 알려지는 등 건강기능성 작물로 국내에서도 전국적으로 재배가 되고 있어서, 국내 재배현황과 재배농가의 실태를 조사하여 재배 애로사항 및 발전과제를 도출코져 하였다. 여주의 국내 재배는 2012년 재배면적이 10ha에서 빠르게 증가하여 2017년 606농가 107.9ha로 정점을 이루고, 점차 감소하여 2019년 232농가 59.9ha에서 재배 하였으며, 2019년 재배면적이 많았던 시군은 함양, 강진, 양주, 천안 등 이었다. 여주의 재배작형은 보통재배(육묘후 노지재배) 농가가 가장 많고, 노지재배(직파), 반촉성재배(조숙재배), 촉성재배 형태의 농가가 있는데, 보통재배(육묘후 노지재배)는 3월 하순~4월 상순에 파종 및 육묘한 후 5월상순 노지에 정식하여, 6월 하순부터 가을에 서리가 내리기 전까지 수확한다. 농가의 재배품종은 일본 등 외국도입종의 종자를 종자회사로 부터 구입하여 재배하고 있으며, 재식방법, 시비관리, 줄기유인 등 표준재배법이 정립되지 못하여 농가별로 다양한 방법으로 재배하고 있는 실정이다. 수확은 열매가 완전히 익기전에 생여주 상태에서 수확하고 있으며, 일반 재배농가는 생여주 판매가 10~20%, 건여주 판매가 80~90% 비율이며, 생여주로 100% 건조업체에 판매하기도 하고, 건여주로 100% 건조하여 판매하는 농가도 있다. 국내재배 안전성 향상을 위하여 필요시 되는 기술개발 과제는 용도별 품종육성 및 종자생산 보급, 고품질 여주 생산을 위한 재배관리 기술, 지역별 생산 여주과실의 성분 품질관리 및 건조 가공기술, 여주의 건강기능성 식품 지정 고시 방안 등으로 전문기관에서의 연구개발이 필요하다.

• The Korean Journal of Pesticide Science
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• v.16 no.1
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• pp.28-34
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• 2012

We analysed 149 samples of Korean traditional herbal tea materials. The 156 pesticides were analyzed by GC/ECD and NPD, detected pesticides were confirmed by GC-TOF/MS. Sample preparation was performed bv multi-residue analysis method of multiclass pesticides of the Korea Food Code. The residual pesticides were detected in 22 samples(14.8%), the highest detection frequency samples are lycium and jujube. Detected pesticides in Korean traditional herbal tea materials were chlorpyrifos (5 samples), chlorothalonil (3 samples), cypermethrin (3 samples), hexaconazol (3 samples) and cyhalothrin(3 samples). The pesticide types detected in Korean traditional herbal tea materials were organophosphorus(29.2%), pyrethroids(16.7%), organochlorines (12.5%) and triazoles(12.5%). The 5 samples(lycium, jujube, chrysanthemum, balloon-flower, milk vetch root) were detected pesticides below MRLs, 2 samples(cornus fruit, cnidium) were detected pesticides unnotificated MRLs.

• Journal of Korean Society of Steel Construction
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• v.22 no.5
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• pp.399-409
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• 2010

Steel structures are threatened to reduce load-carrying capacity as the cross section is decreased by corrosion. However, there has been no method in definitely evaluating residual load-carrying capacity and the effect of corrosion to the load-carrying capacity of steel. This study evaluated tensile residual load-carrying capacity of corroded steel plates by using tensile tests of specimens, which were selected from the web of temporary structure's main beam. After the surface shapes were measured and tensile tests were examined, the rust of 21 corroded specimens was, first of all, removed using a chemical method. From the tensile test result, which of reference specimens that was picked off at the flange of the same main 13-mm-thick beam and corroded specimens were based, surface geometry and correlation with the reduction of corroded thickness and strain, yield strength or tensile strength was established as constant numbers. Effective thickness of corroded steel with irregular cross sections could be calculated using average residual thickness and standard deviation. The irregular cross sections could be the evaluated tensile strength that is equalized to non-corroded uniform steel's regardless of corrosion. Also, reasonable measuring intervals of residual thickness could be proposed by using this result to apply for executive work.

• Journal of the Korean Vacuum Society
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• v.10 no.3
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• pp.380-386
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• 2001

A nuclear microprobe system with adjustable precision object slits and a magnetic quadrupole doublet was designed by the beam optics simulation using a first order matrix formalism, and installed in a $30^{\circ}$ beam line connected with KIGAM 1.7 MV Tandem VDG Accelerator. Demagnification factors for x and y axis are calculated to be 25 and 4.9, respectively, and a minimum beam spot side is expected to be about 5 $\mu\textrm{m}$ for 3 MeV proton beams with a current of about 1 nA. A multi-purpose octagonal target chamber has been built to facilitate MeV ion-beam analytical techniques of PIXE, RBS, ERDA, and ion beam micro-machining. It contains X-ray and particle detectors, a zoom microscope, a Faraday cup, a 4-axis sample manipulator and a high vacuum pumping system. The system performance of the nuclear microprobe is now being tested, and automatic manipulator control and data acquisition system will be installed for routine applications of micro ion-beam analytical techniques.