• Title/Summary/Keyword: Science and engineering

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Optical Method to Determine Gait Parameters Using Position Sensitive Detector

  • Jung, Gu-In;Kim, Ji-Sun;Lee, Tae-Hee;Choi, Ju-Hyeon;Oh, Han-Byeol;Kim, A-Hee;Goh, Bong-Jun;Kim, Jun-Sik;Lee, Eun-Suk;Jun, Jae-Hoon
    • Journal of Electrical Engineering and Technology
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    • v.10 no.5
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    • pp.2155-2161
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    • 2015
  • This study suggests an optical method to measure cardinal of gait (step width, step length, and stride length) with position sensitive detector (PSD). The effect of reflector’s shape (flat and cylinder) on the PSD output voltage was examined for the application of the suggested system to real situations with a curved shape reflector (e.g. shoes). Various mathematical models were evaluated to find the optimal equation for the distance measurement. Considering the effect of shape on detected signal, the inverse polynomial model was developed. The suggested method is simple to operate, low in cost, small in size, and can evaluate gait parameters in real time. This method is expected to be useful in the field of rehabilitation and sport science

Issues with the electrical characterization of graphene devices

  • Lee, Byoung-Hun;Lee, Young-Gon;Jung, Uk-Jin;Kim, Yong-Hun;Hwang, Hyeon-Jun;Kim, Jin-Ju;Kang, Chang-Goo
    • Carbon letters
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    • v.13 no.1
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    • pp.23-28
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    • 2012
  • Graphene is an attractive material for device applications, but device characteristics are very unstable because the graphene is very sensitive to environmental factors such as charges nearby the graphene, metal contacts, defects, contaminants and other adsorbates. Since the interactions between graphene and environmental factors affect the electrical characteristics of graphene devices, the interpretation of electrical characteristics as simple as current-voltage curves is non-trivial, despite the common practice of using well known electrical characterization methods that have been used in silicon MOSFET. This paper addresses major obstacles in the electrical characterization of graphene devices and offers countermeasures to improve the accuracy of electrical characterization methods.

The Effect of Cooling Rate on the Structure and Mechanical Properties of Fe-3%Mn-(Cr)-(Mo)-C PM Steels

  • Sulowski, Maciej;Cias, Andrzej;Frydrych, Hanna;Frydrych, Jerzy;Olszewska, Irena;Golen, Ryszard;Sowa, Marek
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.563-564
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    • 2006
  • The effect of different cooling rate on the structure and mechanical properties of Fe-3%Mn-(Cr)-(Mo)-0.3%C steels is described. Pre-alloyed Astaloy CrM and CrL, ferromanganese and graphite were used as the starting powders. Following pressing in a rigid die, compacts were sintered at $1120^{\circ}C$ and $1250^{\circ}C$ in $H_2/N_2$ atmospheres and cooled with cooling rates $1.4^{\circ}C/min$ and $6.5^{\circ}C/min$. Convective cooled specimens were subsequently tempered at $200^{\circ}C$ for 60 and 240 minutes.

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Recent Approaches to Dialog Management for Spoken Dialog Systems

  • Lee, Cheong-Jae;Jung, Sang-Keun;Kim, Kyung-Duk;Lee, Dong-Hyeon;Lee, Gary Geun-Bae
    • Journal of Computing Science and Engineering
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    • v.4 no.1
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    • pp.1-22
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    • 2010
  • A field of spoken dialog systems is a rapidly growing research area because the performance improvement of speech technologies motivates the possibility of building systems that a human can easily operate in order to access useful information via spoken languages. Among the components in a spoken dialog system, the dialog management plays major roles such as discourse analysis, database access, error handling, and system action prediction. This survey covers design issues and recent approaches to the dialog management techniques for modeling the dialogs. We also explain the user simulation techniques for automatic evaluation of spoken dialog systems.

Angle-sensitive Pixels Based on Subwavelength Compound Gratings

  • Meng, Yunlong;Hu, Xuemei;Yang, Cheng;Shen, Xinyu;Cao, Xueyun;Lin, Lankun;Yan, Feng;Yue, Tao
    • Current Optics and Photonics
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    • v.6 no.4
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    • pp.359-366
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    • 2022
  • In this paper, we present a new design for angle-sensitive pixels (ASPs). The proposed ASPs take advantage of subwavelength compound gratings to capture the light angle, which enables pixel size to reach the wavelength scale of 0.7 ㎛ × 0.7 ㎛. The subwavelength compound gratings are implemented by the wires of the readout circuit inherent to the standard complementary metal-oxide-semiconductor manufacturing process, thus avoiding additional off-chip optics or post-processing. This technique allows the use of two pixels for horizontal or vertical angle detection, and can determine the light's angle in the range from -45° to +45°. The proposed sensor enables surface-profile reconstruction of microscale samples using a lensless imaging system.