• Title/Summary/Keyword: Light control device

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A study on liquid crystal-based electrical polarization control technology for polarized image monitoring device (편광 영상감시 장치를 위한 액정 기반 전기적 편광 조절 기술 연구)

  • Ahn, Hyeon-Sik;Lim, Seong-Min;Jang, Eun-Jeong;Choi, Yoonseuk
    • Journal of IKEEE
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    • v.26 no.3
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    • pp.416-421
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    • 2022
  • In this study, we present a fully automated system that combines camera technology with liquid crystal technology to create a polarization camera capable of detecting the partial linear polarization of light reflected from an object. The use of twisted nematic (TN) liquid crystals that electro-optically modulate the polarization plane of light eliminates the need to mechanically rotate the polarizing filter in front of the camera lens. Images obtained using these techniques are imaged by computer software. In addition, liquid crystal panels have been produced in a square shape, but many camera lenses are usually round, and lighting or other driving units are installed around the lens, so space is optimized through the application of a circular liquid crystal display. Through the development of this technology, an electrically switchable and space-optimized liquid crystal polarizer is developed.

Control of Size and Morphology of Particles Using CO2 Laser in a Flame (화염증 CO2 Laser를 이용한 입자의 크기 및 형상 제어)

  • Lee, Donggeun;Lee, Seonjae;Choi, Mansoo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.11
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    • pp.1379-1389
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    • 1999
  • A new technique for control of size and shape of flame-made particles is Introduced. The characteristic sintering time can be controlled Independently of collision time by heating the particles with irradiation of laser because the sintering time strongly depends on temperature. A coflow oxy-hydrogen diffusion flame burner was used for $SiCl_4$ conversion to silica particle. Nanometer sized aggregates irradiated by a high power CW $CO_2$ laser beam were rapidly heated up to high temperatures and then were sintered to approach volume-equivalent spheres. The sphere collides much slower than the aggregate, which results in reduction of sizes of particles maintaining spherical shape. Light scattering of Ar ion laser and TEM observation using a local sampling device were used to confirm the above effects. When the $CO_2$ laser was irradiated at low position from the burner surface, particle generation due to gas absorption of laser beam occurred and thus scattering intensity increased with $CO_2$ laser power. At high irradiation position, scattering intensity decreased with $CO_2$ laser power and TEM image showed a clear mark of evaporation and recondensation of particles for high $CO_2$ laser power. When the laser was irradiated between the above two positions where small aggregates exist, average size of spherical particles obviously decreased to 58% of those without $CO_2$ laser irradiation with the spherical shape. Even for increased carrier gas flow rate by a factor of three, TEM photograph also revealed considerable reduction of particle size.

The Performance Improvement of a Linear CCD Sensor Using an Automatic Threshold Control Algorithm for Displacement Measurement

  • Shin, Myung-Kwan;Choi, Kyo-Soon;Park, Kyi-Hwan
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.1417-1422
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    • 2005
  • Among the sensors mainly used for displacement measurement, there are a linear CCD(Charge Coupled Device) and a PSD(Position Sensitive Detector) as a non-contact type. Their structures are different very much, which means that the signal processing of both sensors should be applied in the different ways. Most of the displacement measurement systems to get the 3-D shape profile of an object using a linear CCD are a computer-based system. It means that all of algorithms and mathematical operations are performed through a computer program to measure the displacement. However, in this paper, the developed system has microprocessor and other digital components that make the system measure the displacement of an object without a computer. The thing different from the previous system is that AVR microprocessor and FPGA(Field Programmable Gate Array) technology, and a comparator is used to play the role of an A/D(Analog to Digital) converter. Furthermore, an ATC(Automatic Threshold Control) algorithm is applied to find the highest pixel data that has the real displacement information. According to the size of the light circle incident on the surface of the CCD, the threshold value to remove the noise and useless data is changed by the operation of AVR microprocessor. The total system consists of FPGA, AVR microprocessor, and the comparator. The developed system has the improvement and shows the better performance than the system not using the ATC algorithm for displacement measurement.

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A Study on DC Traction Power Supply System Using PWM Converter (PWM컨버터를 적용한 경전철 전력공급시스템에 관한 연구)

  • Kim, Joorak;Park, Chang-Reung;Park, Kijun;Kim, Joo-Uk
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.4
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    • pp.250-254
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    • 2016
  • Currently, power conversion system which converts AC to DC Power is applied in domestic urban railway. The diode rectifier is used in most of them. However the diode rectifier can not control the output voltage and can not regenerate power as well. On the other hand, PWM (pulse width modulation) converter using IGBT (isolated gate bipolar transistor) can control output voltage, allowing it to reduce the output voltage drop. Moreover the Bi-directional conduction regenerates power which does not require additional device for power regeneration control. This paper compared the simulation results for the DC power supply system on both the diode rectifier and the PWM converter. Under the same load condition, simulation circuit for each power supply system was constructed with the PSIM (performance simulation and modeling tool) software. The load condition was set according to the resistance value of the currently operating impedance of light rail line, and the line impedance was set according to the distance of each substations. The train was set using a passive resistor. PI (proportional integral) controller was applied to regulate the output voltage. PSIM simulation was conducted to verify that the PWM Converter was more efficient than the diode rectifier in DC Traction power supply system.

Development of a Monitoring Equipment of Current and Potential on Power Transmission Line for 66kV

  • Nisiyama, Eiji;Kuwanami, Kenshi;Kawano, Mitsunori;Matsuda, Toyonori;Oota, I.
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.41-44
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    • 2003
  • We propose portable equipment that monitors current and voltage of high-potential power transmission lines. In the equipment, a current and voltage sensor are attached to an insulator that supports a power transmission line: A clamped to the power line and the detected current signal is transmitted to the ground station by a wireless optical link using transmission line is detected by a high resistance element, zinc oxide (ZnO). That acts as a potential divider between the power line and ground. We make an experimental device for 66kV power line and demonstrate that it can monitor currents proposed equipment is small-sized, light, and inexpensive in comparison with the conventional CT (current transformer) and PT (potential transformer) since it does not require high potential insulators and magnetic cores, further, the equipment is easily installed owing to its small size and its simple structure.

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Characterization of Nanoscale Electroactive Polymers via Piezoelectric Force Microscopy

  • Lee, Su-Bong;Ji, Seungmuk;Yeo, Jong-Souk
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.232.2-232.2
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    • 2015
  • Piezoelectric force microscopy (PFM) is a powerful method to characterize inversed piezoelectric effects directly using conductive atomic force microscopy (AFM) tips. Piezoelectric domains respond to an applied AC voltage with a characteristic strain via a contact between the tip and the surface of piezoelectric material. Electroactive piezoelectric polymers are widely investigated due to their advantages such as flexibility, light weight, and microactuation enabling various device features. Although piezoelectric polymers are promising materials for wide applications, they have the primary issue that the piezoelectric coefficient is much lower than that of piezoelectric ceramics. Researchers are studying widely to enhance the piezoelectric coefficient of the materials including nanoscale fabrication and copolymerization with some materials. In this report, nanoscale electroactive polymers are prepared by the electrospinning method that provides advantages of direct poling, scalability, and easy control. The main parameters of the electrospinning process such as distance, bias voltage, viscosity of the solution, and elasticity affects the piezoelectric coefficient and the nanoscale structures which are related to the phase of piezoelectric polymers. The characterization of such electroactive polymers are conducted using piezoelectric force microscopy (PFM). Their morphologies are characterized by field emission-scanning electron microscope (FE-SEM) and the crystallinity of the polymer is determined by X-ray diffractometer.

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The effect of infrared rays diode irradiation on collagen formation (적외선 레이저 다이오드가 콜라겐 형성에 미치는 영향)

  • Kim, Tae-Gon;Kim, Toung-Pyo;Lee, Ho-Sic;Park, Yong-Pil;Cheon, Min-Woo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.411-411
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    • 2009
  • Low level laser therapy has various therapy effects. This paper performed the basic study for developing the Low Level Laser Therapy Equipment for medical treatment. The apparatus has been fabricated using the laser diode and microprocessor unit. This equipment was fabricated using a micro-controller and a laser diode, and designed to enable us to control light irradiation time, frequency and so on. In this study, the designed device was used to find out how infrared laser diode affected the collagen formation. For in-vivo test, a round wound 1cm in diameter was cut from the test animal whose epidermal and dermal layers were removed. Test animals were relieved for 24 hours after wounds had been excised and then the infrared laser irradiation group was given irradiation therapy over 9 days one 20 min per day. As a result, More collagenosis occurred in the order of infrared laser irradiation and non-irradiation group. Collagenosis is closely related to wound repair and it was found that infrared laser irradiation groups had more collagenosis and was quicker to recover from wound than non-irradiation group.

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Implementation of a Spring Backboned Soft Arm Emulating Human Gestures (인간 동작 표현용 스프링 백본 구조 소프트 암의 구현)

  • Yoon, Hyun-Soo;Choi, Jae-Yeon;Oh, Se-Min;Lee, Byeong-Ju;Yoon, Ho-Sup;Cho, Young-Jo
    • The Journal of Korea Robotics Society
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    • v.7 no.2
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    • pp.65-75
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    • 2012
  • This study deals with the design of a spring backboned soft arm, which will be employed for generation of human gesture as an effective means of Human Robot interaction. The special features of the proposed mechanism are the light weight and the flexibility of the whole mechanism by using a spring backbone. Thus, even in the case of collision with human, this device is able to absorb the impact structurally. The kinematics and the design for the soft arm are introduced. The performance of this mechanism was shown through experiment emulating several human gestures expressing human emotion and some service contents. Finally, this soft arm was implemented as the wing mechanism of a penguin robot.

Study of plasma induced charging damage and febrication of$0.18\mu\textrm{m}$dual polysilicon gate using dry etch (건식각을 이용한 $0.18\mu\textrm{m}$ dual polysilicon gate 형성 및 plasma damage 특성 평가)

  • 채수두;유경진;김동석;한석빈;하재희;박진원
    • Journal of the Korean Vacuum Society
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    • v.8 no.4A
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    • pp.490-495
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    • 1999
  • In 0.18 $\mu \textrm m$ LOGIC device, the etch rate of NMOS polysilicons is different from that of PMOS polysilicons due to the state of polysilicon to manufacture gate line. To control the etch profile, we tested the ratio of $Cl_2$/HBr gas and the total chamber pressure, and also we reduced Back He pressure to get the vertical profile. In the case of manufacturing the gate photoresist line, we used Bottom Anti-Reflective Coating (BARC) to protect refrection of light. As a result we found that $CF_4O_2$ gas is good to etch BARC, because of high selectivity and good photoresist line profile after etching BARC. in the results of the characterization of plasma damage to the antenna effect of gate oxide, NO type thin film(growing gate oxide in 0, ambient followed by an NO anneal) is better than wet type thin film(growing gate oxide in $0_2+H_2$ ambient).

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Development of Data Fusion Human Identification System Based on Finger-Vein Pattern-Matching Method and photoplethysmography Identification

  • Ko, Kuk Won;Lee, Jiyeon;Moon, Hongsuk;Lee, Sangjoon
    • International Journal of Internet, Broadcasting and Communication
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    • v.7 no.2
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    • pp.149-154
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    • 2015
  • Biometric techniques for authentication using body parts such as a fingerprint, face, iris, voice, finger-vein and also photoplethysmography have become increasingly important in the personal security field, including door access control, finance security, electronic passport, and mobile device. Finger-vein images are now used to human identification, however, difficulties in recognizing finger-vein images are caused by capturing under various conditions, such as different temperatures and illumination, and noise in the acquisition camera. The human photoplethysmography is also important signal for human identification. In this paper To increase the recognition rate, we develop camera based identification method by combining finger vein image and photoplethysmography signal. We use a compact CMOS camera with a penetrating infrared LED light source to acquire images of finger vein and photoplethysmography signal. In addition, we suggest a simple pattern matching method to reduce the calculation time for embedded environments. The experimental results show that our simple system has good results in terms of speed and accuracy for personal identification compared to the result of only finger vein images.