• Title/Summary/Keyword: V/F Control

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Low Complexity Gradient Magnitude Calculator Hardware Architecture Using Characteristic Analysis of Projection Vector and Hardware Resource Sharing (정사영 벡터의 특징 분석 및 하드웨어 자원 공유기법을 이용한 저면적 Gradient Magnitude 연산 하드웨어 구현)

  • Kim, WooSuk;Lee, Juseong;An, Ho-Myoung
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.9 no.4
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    • pp.414-418
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    • 2016
  • In this paper, a hardware architecture of low area gradient magnitude calculator is proposed. For the hardware complexity reduction, the characteristic of orthogonal projection vector and hardware resource sharing technique are applied. The proposed hardware architecture can be implemented without degradation of the gradient magnitude data quality since the proposed hardware is implemented with original algorithm. The FPGA implementation result shows the 15% of logic elements and 38% embedded multiplier savings compared with previous work using Altera Cyclone VI (EP4CE115F29C7N) FPGA and Quartus II v15.0 environment.

EMG Power Spectrum Analysis of Wearing Roller Shoes on Muscle Fatigue in the Lower Extremity during Walking (롤러 슈즈 착용 후 보행시 근피로 상태에서 하지근의 근전도 Power Spectrum 분석)

  • Kim, Youn-Joung;Yoon, Chang-Jin;Chae, Won-Sik;Lee, Min-Hyung;Kim, Hun-Soo;Jung, Mi-Ra
    • Korean Journal of Applied Biomechanics
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    • v.17 no.2
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    • pp.239-245
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    • 2007
  • The purpose of this study was to compare the electromyography signal's power spectrum mean and median tendencies appearing in the lower extremity during walking while wearing roller shoes. 9 male subjects volunteered who have no experience riding inline-skate or roller-skate, and have no record of musculoskeletal disorder. Subjects walked on treadmill twice for an hour (Once a week, one trial with the roller on and the other without roller, Walking velocity = 1.39 m/s). Electromyography was measured every 15 minute (0, 15, 30, 45, 60 minutes). Surface electrode sticked muscle at rectus femoris(R.F.), vastus lateralis(V.L.), vastus medialis(V.M.), biceps femoris(B.F.), tibialis anterior(T.A.), gastrocnemius lateralis(G.L.), gastrocnemius medialis(G.M.). At Rectus femoris, Vastus Lateralis, Vastus medialis, and Biceps femoris showed no statistically significant decrease of median frequency or mean edge frequency as time passes. Also, between two treatments (wearing the roller shoes vs not wearing the roller shoes), no statistically significant difference. After 60 minutes, mean edge frequency showed statistically significant decrease at tibalis anterior and after 45 minutes, mean edge frequency showed statistically significant decrease compared to wearing roller shoes without the wheels at gastrocnemius lateralis. At gastrocnemius medialis after 30 minutes, median frequency showed statistically significant decrease, and showed statistically significant difference compared to the control group. Wearing the roller shoes with wheels for a long time resulted in statistically significant decrease of mean edge frequency and median frequency in lower extremity, especially in shank muscles. Increase of wearing time of roller shoes and walking on a bumpy road wearing roller shoes with wheels result fatigue and thus, danger of injury.

The Output Characteristics of Low Repetition·High Power Nd:YAG Laser Using LLC Resonant Converter (LLC 공진형 컨버터를 활용한 저 반복·고출력 Nd:YAG 레이저의 출력특성)

  • Lee, Hee-Chang
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.3
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    • pp.286-291
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    • 2015
  • LLC resonant converter is used to control laser output power in Nd:YAG laser. Zero voltage switching (ZVS) is implemented to minimize the switching loss which is adopting the LLC resonant converter. In the spot welding processing of metal thin films, the processing quality is decided by the laser beam output energy of single pulse. We decide to the 50 [J] as the single pulse laser beam energy. Laser output power is investigated and experimented by changing the output current. That current is controled by the charging voltage of capacitor. From those results, we obtained the maximum laser output of 58.2 [J] and the conversion efficiency of 2.52% at the discharge voltage of 620V and the discharge current of 861 [A] and the pulse repetition rate of 1 [Hz] at the charging capacitor of 12,000 [${\mu}F$].

Seedling Emergence of Direct Seeded Paddy Rice at Different Soil Moisture Regimes (벼 건답직파재배에서 토양수분이 출아에 미치는 영향)

  • 이석순;백준호;김태주;홍승범
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.38 no.3
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    • pp.228-234
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    • 1993
  • Seedling emergence of 15 rice varieties (Gayabyeo, Chilseongbyeo, Samgangbyeo, Yeongsanbyeo, Yeongdeugbyeo, Hwajinbyeo, Palgongbyeo, Seomjinbyeo, Tamjinbyeo, Milyang 95, M 101, M 202, Newbonnet, Tebonnet, and Lemont) were tested at different soil moisture regimes and seeding depths. Submergence for four days immediately after seeding did not reduce emergence rate in all varieties. Under the flooded condition, the percentage of emergence of all varieties at 1.5cm seeding depth ranged 0~40%, it is much lower compared to uncovered control, and percentage of seedling survival ranged 0~24% due to death of some emerged seedlings. Under the field condition, one time flooding up to 10cm above the soil surface after seeding did not reduce the percent emergence of seedlings. The pF value of soil was 0 for few days after flooding or raining and Eh of soil ranged 443-453m V.

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Composite Pressure Vessel for Natural Gas Vehicle by Filament Winding (필라멘트 와인딩 공정에 의한 천연가스 차량용 복합재료 압력용기)

  • 김병선;김병하;김진봉
    • Composites Research
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    • v.17 no.5
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    • pp.1-6
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    • 2004
  • Composite pressure vessels with HDPE (high density polyethlyne) liner with metal boss at each end were developed by Filament Winding Process. The vessel is composed of a dome-shaped part at each end and a cylinder-shaped part at the middle of the vessel. The environmental tests carried out for possible vessel materials such as High Density Polyethlyn (HDPE), resins and reinforcing fibers up to a year showed no significant damages. The boss was designed to minimize the gas leak which was verified by FEM analysis. Most ideal fiber tension was obtained by experimental method and the fiber volume fraction, $\textrm{V}_{f}$, obtained by image analyzer were 55.4 % in cylinder and 55.6 % in dome parts, respectively. Winding pattern is programmed to control the composite thickness in the dome areas such that the failure of the vessel may occur in the cylinder. During the cure, the vessel was rotated and a constant internal pressure of 0.62 bar was applied. From this, the vessel's burst pressure is improved by 28 %. The burst and fatigue tests for under-wound and fully wound vessel showed satisfactory results.

Electrochemical Properties of Activated Carbon Capacitor Adopting a Proton-conducting Hydrogel Polymer Electrolyte (수소이온전도성 고분자 겔전해질을 적용한 활성탄소계 전기이중층 캐패시터의 전기화학적 특성)

  • Latifatu, Mohammed;Kim, Kwang Man;Kim, Yong Joo;Ko, Jang Myoun
    • Elastomers and Composites
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    • v.47 no.4
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    • pp.292-296
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    • 2012
  • An electric double-layer capacitor (ELDC) of activated carbon electrode is prepared using a proton-conducting hydrogel polymer electrolyte, which is composed of poly(vinyl alcohol), silicotungstic acid, $H_3PO_4$, and deionized water. A solid film by evaporating the hydrogel polymer electrolyte is also prepared for comparison. The hydrogel polymer electrolyte also acts as a separator with the thickness of about $80{\mu}m$ and the room-temperature ionic conductivity of $10^{-2}S\;cm^{-1}$. The EDLC containing the symmetric electrodes of activated carbon shows the specific capacitance of $58F\;g^{-1}$ at $100mV\;s^{-1}$ with a good cycle life, implying that the hydrogel polymer electrolyte is very promising for use in EDLCs.

Gradient Magnitude Hardware Architecture based on Hardware Folding Design Method for Low Power Image Feature Extraction Hardware Design (저전력 영상 특징 추출 하드웨어 설계를 위한 하드웨어 폴딩 기법 기반 그라디언트 매그니튜드 연산기 구조)

  • Kim, WooSuk;Lee, Juseong;An, Ho-Myoung
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.10 no.2
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    • pp.141-146
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    • 2017
  • In this paper, a gradient magnitude hardware architecture based on hardware folding design method is proposed for low power image feature extraction. For the hardware complexity reduction, the projection vector chracteristic of gradient magnitude is applied. The proposed hardware architecture can be implemented with the small degradation of the gradient magnitude data quality. The FPGA implementation result shows the 41% of logic elements and 62% embedded multiplier savings compared with previous work using Altera Cyclone VI (EP4CE115F29C7N) FPGA and Quartus II v16.0 environment.

Synthesis, Spectral, Characterization, DFT and Biological Studies of New 3-[(3-Chlorophenyl)-hydrazono]-pentane-2,4-dione Metal Complexes

  • Sadeek, Sadeek A.;Zordok, Wael A.;El-Farargy, Ahmed F.;El-Desoky, Sameh I.
    • Journal of the Korean Chemical Society
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    • v.58 no.2
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    • pp.169-178
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    • 2014
  • A new series of metal complexes of V(IV), Pd(II), Pt(IV), Ce(IV) and U(VI) with 3-[(3-chlorophenyl)-hydrazono]-pentane-2,4-dione (Cphpd) were synthesized and characterized by elemental analysis, molar conductivity, magnetic moment measurements, UV-vis, FT-IR and $^1H$ NMR as well as TG-DTG techniques. The data indicated that the Cphpd acts as a bidentate ligand through the hydrazono nitrogen and one keto oxygen. The kinetic parameters have been evaluated by using Coats Redfern (CR) and Horowitz-Metzeger (HM) methods. The thermodynamic data reflected the thermal stability for all complexes. The calculated bond length and the bond stretching force constant, F(U=O), values for $UO_2$ bond are $0.775{\AA}$ and $286.95Nm^{-1}$. The bond lengths, bond angles, dipole moment and the lowest energy model structure of the complexes have been determined with DFT calculations. The antimicrobial activity of the synthesized ligand and its complexes were screened.

A Study on the Visual Evaluation According to Changes in Width of Hem Line and Waistline Position of Flare Pants (플레어 팬츠의 바지부리 폭과 허리선 위치의 변화에 따른 시각적 평가)

  • Lee, Jung-Soon
    • Journal of the Korea Fashion and Costume Design Association
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    • v.14 no.4
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    • pp.127-137
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    • 2012
  • The purpose of this study is to recognize the differences of visual evaluation by variations in width of hem line and waistline position of the flare pants. The stimuli are 9 samples: One control group, 3 variations of the width of hem line and 3 variations of the waistline position. The data has been obtained from 44 fashion students. The data has been analyzed by Factor Analysis, Anova, Scheffe's Test and the MCA method. The results of the study are as follows: The visual evaluation by the width of hem line and waistline position of flare pants are composed of 5 factors : physical characteristics, elegance, originality, comfort, and stiffness. Among these factors, the physical characteristic is evaluated to be the most important factor. As a v isual evaluation result o f changes in the width o f hern l ine, 8 4 cm in width (the narrowest width) was highly evaluated in physical characteristics, elegance, and originality factors. For the result of changes in the waistline position, high-waisted flare pants were highly effective in physical characteristics, and also evaluated well in elegance, originality and stiffness factors. The flare pants did not show any interaction between the width of hem line and waistline position. The waistline position had more influence on visual evaluation in physical characteristics, originality and comfort factors while elegance and stiffness factors were affected by the width of hem line.

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Grading of Harvested 'Mihwang' Peach Maturity with Convolutional Neural Network (합성곱 신경망을 이용한 '미황' 복숭아 과실의 성숙도 분류)

  • Shin, Mi Hee;Jang, Kyeong Eun;Lee, Seul Ki;Cho, Jung Gun;Song, Sang Jun;Kim, Jin Gook
    • Journal of Bio-Environment Control
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    • v.31 no.4
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    • pp.270-278
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    • 2022
  • This study was conducted using deep learning technology to classify for 'Mihwang' peach maturity with RGB images and fruit quality attributes during fruit development and maturation periods. The 730 images of peach were used in the training data set and validation data set at a ratio of 8:2. The remains of 170 images were used to test the deep learning models. In this study, among the fruit quality attributes, firmness, Hue value, and a* value were adapted to the index with maturity classification, such as immature, mature, and over mature fruit. This study used the CNN (Convolutional Neural Networks) models for image classification; VGG16 and InceptionV3 of GoogLeNet. The performance results show 87.1% and 83.6% with Hue left value in VGG16 and InceptionV3, respectively. In contrast, the performance results show 72.2% and 76.9% with firmness in VGG16 and InceptionV3, respectively. The loss rate shows 54.3% and 62.1% with firmness in VGG16 and InceptionV3, respectively. It considers increasing for adapting a field utilization with firmness index in peach.