• Title/Summary/Keyword: Electronic devices

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Design and Implementation of Electromyographic Sensor System for Wearable Computing (웨어러블 컴퓨팅을 위한 근전도 센서 시스템의 설계 및 구현)

  • Lee, Young-Seok
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.11 no.1
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    • pp.114-120
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    • 2018
  • In this paper we implemented an EMG sensor system for wearable devices to obtain and analyze of EMG signals. The performance of the implemented sensor system is evaluated by the correlation analysis of muscle fatigue and muscle activation to clinical EMG system and compared with power consumption of the measured power of our system and commercial systems. In experiments with biceps and triceps brachii of 5 objects, The correlation values of muscle fatigue and muscle activation between our system and the clinical EMG system is 1.1~1.4 and about 1.0, respectively. And also the power consumption of our system is 25~50% less than that of some commercial EMG sensor systems.

Point Cloud Data Driven Level of detail Generation in Low Level GPU Devices (Low Level GPU에서 Point Cloud를 이용한 Level of detail 생성에 대한 연구)

  • Kam, JungWon;Gu, BonWoo;Jin, KyoHong
    • Journal of the Korea Institute of Military Science and Technology
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    • v.23 no.6
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    • pp.542-553
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    • 2020
  • Virtual world and simulation need large scale map rendering. However, rendering too many vertices is a computationally complex and time-consuming process. Some game development companies have developed 3D LOD objects for high-speed rendering based on distance between camera and 3D object. Terrain physics simulation researchers need a way to recognize the original object shape from 3D LOD objects. In this paper, we proposed simply automatic LOD framework using point cloud data (PCD). This PCD was created using a 6-direct orthographic ray. Various experiments are performed to validate the effectiveness of the proposed method. We hope the proposed automatic LOD generation framework can play an important role in game development and terrain physic simulation.

Development of High Performance Photoelectrode Paste Doped Glass Powder for Dye-sensitized Solar Cells (염료감응형 태양전지용 유리분말이 함유된 고효율 광전극 페이스트 개발)

  • Zhao, Xing Guan;Jin, En Mei;Gua, Hal-Bon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.5
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    • pp.427-431
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    • 2011
  • Hybrid $SiO_2-TiO_2$ photoelectrode with different type of layers was investigated in dye-sensitized solar cells (DSSC). Use of a thin layer of nanocrystalline $TiO_2$ would imply reduction in the amount of dye coverage, however, lower amount of dye in the thin films would imply fewer electron generation upon illumination. So, thus, it becomes necessary to include a $SiO_2-TiO_2$ layer for increase light harvesting effect such that the lower photon conversion due to thin layer could be compensated. In this paper reports the use of transparent high surface area $TiO_2$ layer and an additional $SiO_2-TiO_2$ layer, thus ensuring adequate light harvesting in these devices. The best solar conversion efficiency 6.6% under AM 1.5 was attained with a multi-layer structure using $TiO_2$ layer/$SiO_2-TiO_2$ layer/$TiO_2$ layer for the light harvesting and this had resulted to about 44% increase in photocurrent density of dye-sensitized solar cells.

Analysis on Current Limiting Characteristics of Flux-Lock Type SFCL Using a Transformer Winding (변압기 권선을 이용한 자속구속형 초전도 전류제한기의 전류제한 특성 분석)

  • Han, Tae-Hee;Lim, Sung-Hun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.2
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    • pp.136-140
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    • 2011
  • The fault current limiting characteristics of the flux-lock type superconducting fault current limiter (SFCL) using a transformer winding were investigated. The suggested flux-lock type SFCL consists of two parallel connected coils on an iron core and the transformer winding connected in series with one of two coils. In this SFCL, the high-TC superconducting (HTSC) element was connected with the secondary side of the transformer. The short-circuit experimental devices to analyze the fault current limiting characteristics of the flux-lock type SFCL using the transformer winding were constructed. Through the short-circuit tests, the flux-lock type SFCL using transformer winding was shown to perform more effective fault current limiting operation compared to the previous flux-lock type SFCL without the transformer winding from the viewpoint of the quench occurrence and the recovery time of the HTSC element.

Efficiency Improvement of OLEDs depending on the Hole-size of Crucible Boat (Crucible Boat의 홀 크기에 따른 유기발광소자의 효율 개선)

  • Kim, Weon-Jong;Hong, Jin-Woong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.6
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    • pp.569-574
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    • 2008
  • In the device structure of ITO/tris(8-hydroxyquinoline) aluminum ($Alq_3$)/Al device, we investigated the efficiency improvement of organic light-emitting diodes (OLEDs) depending on the hole-size of crucible boat. The device was manufactured using a thermal evaporation under the base pressure of $5{\times}10^{-6}\;Torr$. The $Alq_3$ organics were evaporated to be 100 nm thick at a deposition rate of $1.5\AA/s$, and in order to investigate the optimal surface roughness of $Alq_3$, the $Alq_3$ was thermally evaporated to be 0.8 mm, 1.0 mm, and 1.5 mm as a hole-size of the boat, respectively. We found that luminance and external quantum efficiency are superior when the hole-size of the boat is 1.0 mm. The external quantum efficiency of the device made with the hole-size of 1.0 mm boat were improved by a factor of ten compared to the devices made with the hole-size of non boat.

Investigations of Ferroelectric Polarization Switching in Potassium Nitrate Composite Films

  • Kumar, Neeraj;Nath, Rabinder
    • Transactions on Electrical and Electronic Materials
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    • v.15 no.2
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    • pp.60-65
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    • 2014
  • This article explains the experimental results of ferroelectric polarization switching (FPS) of potassium nitrate ($KNO_3$) with different polymers such as polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF) using simple melt-press techniques. To analyze the ferroelectric polarization switching in potassium nitrate ($KNO_3$) composite films at room temperature, we applied the Ishibashi and Takagi theory (based on Avrami model) to the switching current transient. To investigate the dimensionality of domain growth, the ferroelectric polarization switching current (FPS current) was observed from the square - wave bipolar signals across a resistance of $0.1k{\Omega}$ in series with the composite films. The existence of a switching current transient pulse confirmed the ferroelectricity and indicated the stability of the ferroelectric phase (phase III) of $KNO_3$ at room temperature. Polarization hysteresis (P-E) characteristics supported the prominent features of ferroelectric polarization switching in the composite films at room temperature.

Study on Industrial Inverters for Driving High-efficiency High-voltage Field-stop IGBT Optimization Design (산업용 인버터 구동을 위한 고효율 고내압 Field-stop IGBT 최적화 설계에 관한 연구)

  • Lee, Myung Hwan;Kim, Bum June;Jung, Eun Sik;Jung, Hun Suk;Kang, Ey Goo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.4
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    • pp.257-263
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    • 2013
  • In this paper, Solar, Wind, fuel cell used in a Power conversion devices and industrial inverter motor to increase the efficiency of energy consumption, which is a core part of high-efficiency, high-voltage Trench Gate Field Stop IGBT was studied. For this purpose Planar type NPT IGBT and Planar type Field Stop IGBT have designed a basic structure designed to Trench Gate Field Stop IGBT based on the completed structure by analyzing the energy consumption of electrical characteristics, efficiency is a key part, high-efficiency and high-voltage inverter for industry regarding the optimization design for Trench Gate Field Stop IGBT.

Optimization of Bismuth-Based Inorganic Thin Films for Eco-Friend, Pb-Free Perovskite Solar Cells (친환경 Pb-Free 페로브스카이트 태양전지를 위한 비스무스 기반의 무기 박막 최적화 연구)

  • Seo, Ye Jin;Kang, Dong-Won
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.31 no.2
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    • pp.117-121
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    • 2018
  • Perovskite solar cells have received increasing attention in recent years because of their outstanding power conversion efficiency (exceeding 22%). However, they typically contain toxic Pb, which is a limiting factor for industrialization. We focused on preparing Pb-free perovskite films of Ag-Bi-I trivalent compounds. Perovskite thin films with improved optical properties were obtained by applying an anti-solvent (toluene) washing technique during the spin coating of perovskites. In addition, the surface condition of the perovskite film was optimized using a multi-step thermal annealing treatment. Using the optimized process parameters, $AgBi_2I_7$ perovskite films with good absorption and improved planar surface topography (root mean square roughness decreased from 80 to 26 nm) were obtained. This study is expected to open up new possibilities for the development of high performance $AgBi_2I_7$ perovskite solar cells for applications in Pb-free energy conversion devices.

A Comparison Study Between International Standard and Statistical Analysis on LED Package Life (국제표준과 통계적 분석을 통한 LED Package 수명 비교 연구)

  • Park, Se Il;Kim, Gun So;Kim, Chung Hyeok
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.31 no.2
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    • pp.122-127
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    • 2018
  • In an attempt to estimate the life projection of LED packages, IESNA published a paper regarding an LED package measurement test method in 2008, and a life projection technical document in 2011, to be used for LED life estimation. IESNA's publications regarding LED package measurement methods were functional, but they were not internationally standardized before 2017. In order to develop a standardized method, the International Standard chose to use the LM-80 as a measurement method for LED life projection in their publication in 2017. Many projection methods have been discussed by the IEC Technical Committee 34 working group, including the method using an exponential function, which reflects lumen degradation characteristics well. This study is designed to explore alternative LED package life estimation methods using an exponential function with statistical analysis, other than the one suggested by the International Standard.

Characteristic of Transient Response in Nonuniform Instability with Optically Controlled Fiber (광학적으로 제어된 섬유를 가진 비균일 불안정성의 과도 응답의 특성)

  • Han, Pan-Lin;Park, Kwang-Chea
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.9 no.5
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    • pp.445-450
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    • 2016
  • In this paper we study the effect of chaos in nonuniform instability with optical fiber based IoT networks. The transient response of optically controlled fiber has also described. Nonlinear optical fiber effects especially fiber scattering in networks has emerged as the essential means active optical devices. The paradigm instability in fiber Internet serves as a test for fundamental study of chaos and its suppression and exploitation in practical application in optical communication. This paper attempts to present a survey and some of our research findings on the nature of chaotic effect on Internet based optical communication. The transient response in optical fiber has been evaluated theoretically by calculating the variation of the scattering function. The lines has used under open ended termination containing optically induced region. The scattered optical waves in a fiber used in optic communications are temporally unstable above certain threshold intensity.