• Title/Summary/Keyword: sensor density

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Partial Discharge Characteristics of n-butyl acrylate grafted Polyethylenes (n-butyl acrylate로 그라프트된 폴리에틸렌의 부분방전 특성)

  • 이정원;서광석;곽희로
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.11a
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    • pp.489-492
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    • 1997
  • Partial discharge characteristics of normal butyl acrylate grafted low density polyethylenes were investigated by an ultrasonic sensor made of ceramic piezoelectric material. It was found that the partial discharging activities in normal butyl acrylate grafted low density polyethylenes were considerably suppressed compared to those in plain low density polyethylene. It was found that acrylic acid grafted polyethylene was more effective than normal butyl acrylate grafted low density polyethylene.

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Estimation of the Sensing Ability of HH Smart Sensor According to Acceleration Value Changing (가속도 값 변화에 따른 HH 스마트센서의 센싱능력 평가)

  • Hwang, Seong-Youn;Hong, Dong-Pyo;Park, Jun-Hong
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.527-532
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    • 2001
  • In this paper, we will propose the new method that estimates the sensing ability of HH smart sensor. We have developed a new signal processing method that can distinguish among different materials relatively. The HH smart sensor was developed for recognition of materials. We made the HH smart sensor in our experiment. Then, we estimated the ability to recognize objects according to acceleration value. We estimated the sensing ability of HH smart sensor with the $R_{SAI}$ method. Experiments and analysis were executed to estimate the ability to recognize objects according to acceleration value changing. Dynamic characteristics of HH smart sensor were evaluated relatively through a new $R_{SAI}$ method that uses the power spectrum density. Applications of this method are for finding abnormal conditions of objects (auto-manufacturing), feeling of objects (medical product), robotics, safety diagnosis of structure, etc.

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Estimation of the Sensing Ability of HH Smart Sensor According to Acceleration Value Changing (가속도 값 변화에 따른 지능센서(HH)의 센싱능력 평가)

  • 황성연;홍동표;김홍건
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.1
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    • pp.22-27
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    • 2004
  • A new method that estimates the sensing ability of HH smart sensor is proposed. The new signal processing method have been developed that can distinguish among different materials relatively. The HH smart sensor was developed far recognition of materials. The HH smart sensor was made for experiment. Then, it was estimated the ability to recognize objects according to acceleration value. The sensing ability of HH smart sensor has been estimated with the $R_{SAI}$ method. Experiments and analysis were executed to estimate the ability to recognize objects according to acceleration value changing. Dynamic characteristics of HH smart sensor were evaluated relatively through a new $R_{SAI}$ method that uses the power spectrum density. Applications of this method are for finding abnormal conditions of objects (auto-manufacturing), feeling of objects (medical product), robotics, safety diagnosis of structure, etc.

Map Error Measuring Mechanism Design and Algorithm Robust to Lidar Sparsity (라이다 점군 밀도에 강인한 맵 오차 측정 기구 설계 및 알고리즘)

  • Jung, Sangwoo;Jung, Minwoo;Kim, Ayoung
    • The Journal of Korea Robotics Society
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    • v.16 no.3
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    • pp.189-198
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    • 2021
  • In this paper, we introduce the software/hardware system that can reliably calculate the distance from sensor to the model regardless of point cloud density. As the 3d point cloud map is widely adopted for SLAM and computer vision, the accuracy of point cloud map is of great importance. However, the 3D point cloud map obtained from Lidar may reveal different point cloud density depending on the choice of sensor, measurement distance and the object shape. Currently, when measuring map accuracy, high reflective bands are used to generate specific points in point cloud map where distances are measured manually. This manual process is time and labor consuming being highly affected by Lidar sparsity level. To overcome these problems, this paper presents a hardware design that leverage high intensity point from three planar surface. Furthermore, by calculating distance from sensor to the device, we verified that the automated method is much faster than the manual procedure and robust to sparsity by testing with RGB-D camera and Lidar. As will be shown, the system performance is not limited to indoor environment by progressing the experiment using Lidar sensor at outdoor environment.

Micropower energy harvesting using high-efficiency indoor organic photovoltaics for self-powered sensor systems

  • Biswas, Swarup;Lee, Yongju;Kim, Hyeok
    • Journal of Sensor Science and Technology
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    • v.30 no.6
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    • pp.364-368
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    • 2021
  • We developed a highly efficient organic photovoltaic (OPV) cell with a poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)]:[6,6]-phenyl-C71-butyric acid methyl ester active layer for harvesting lower-intensity indoor light energy to power various self-powered sensor systems that require power in the microwatt range. In order to achieve higher power conversion efficiency (PCE), we first optimized the thickness of the active layer of the OPV cell through optical simulations. Next, we fabricated an OPV cell with optimized active layer thickness. The device exhibited a PCE of 12.23%, open circuit voltage of 0.66 V, short-circuit current density of 97.7 ㎂/cm2, and fill factor of 60.53%. Furthermore, the device showed a maximum power density of 45 ㎼/cm2, which is suitable for powering a low-power (microwatt range) sensor system.

An Estimation Methodology of Empirical Flow-density Diagram Using Vision Sensor-based Probe Vehicles' Time Headway Data (개별 차량의 비전 센서 기반 차두 시간 데이터를 활용한 경험적 교통류 모형 추정 방법론)

  • Kim, Dong Min;Shim, Jisup
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.21 no.2
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    • pp.17-32
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    • 2022
  • This study explored an approach to estimate a flow-density diagram(FD) on a link in highway traffic environment by utilizing probe vehicles' time headway records. To study empirical flow-density diagram(EFD), the probe vehicles with vision sensors were recruited for collecting driving records for nine months and the vision sensor data pre-processing and GIS-based map matching were implemented. Then, we examined the new EFDs to evaluate validity with reference diagrams which is derived from loop detection traffic data. The probability distributions of time headway and distance headway as well as standard deviation of flow and density were utilized in examination. As a result, it turned out that the main factors for estimation errors are the limited number of probe vehicles and bias of flow status. We finally suggest a method to improve the accuracy of EFD model.

Design of a Magnet Assembly for an NMR Based Sensor Using Finite Element Analysis

  • Cho, S.I.;Chung, C.H.;Kim, S.C.
    • Agricultural and Biosystems Engineering
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    • v.1 no.1
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    • pp.49-53
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    • 2000
  • A magnet assembly is a critical element of a nuclear magnetic resonance(NMR) based sensor. Magnetic flux density and homogeneity are essential to its optimum performance. Geometry and magnet material properties determine the magnetic flux density and homogeneity of the assembly. This study was carried out to develop the design for a magnet assembly. A 2-D finite element model for the magnetic assembly was developed using ANSYS and evaluated the effects of adding shimming frames and steel bars in the corners of the rectangular steel cover which surrounded the magnet. The assembly was manufactured and evaluated. According to the ANSYS model, modified pole frames increased magnetic flux density by 8.3% and increased homogeneity by 83%. Addition of steel bars in the corners increased the magnetic flux density by 1%, and improved homogeneity up to three times. The difference between simulated and measured magnetic flux densities at the center point of the air gap was within 2.4%.

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Modelling of a Ring-type Multi-pole Inductive Position Sensor Using Magnetic Circuit Theory (자기회로 이론을 이용한 링형 다극 유도형 변위센서의 모델링)

  • 김지미;노명규
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.207-211
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    • 2004
  • The performance of an inductive position sensor has approved by previous research papers. In this paper, magnetic circuit model of a ring-type multi-pole insuctive position sensor is described. The magnetic circuit model is required to design in ductive position sensor as well as draw a fault tolerance algorithm. Using the magnetic circuit theory, we derived the relationship between voltage applied and flux density in the normal air-gap. By idealizing the modulation/demodulation processes of signal processing circuit, sensor gain with respect to change of displacement is theoretically calculation using the magnetic circuit model, which validate the theoretical derivation.

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Effects of Impulsive Noise on the Performance of Uniform Distributed Multi-hop Wireless Sensor Networks

  • Rob, Jae-Sung
    • Journal of information and communication convergence engineering
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    • v.5 no.4
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    • pp.300-304
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    • 2007
  • Wireless sensor networks represent a new and exciting communication paradigm which could have multiple applications in future wireless communication. Therefore, performance analysis of such a wireless sensor network paradigm is needed in complex wireless channel. Wireless networks could be an important means of providing ubiquitous communication in the future. In this paper, the BER performance of uniform distributed wireless sensor networks is evaluated in non-Gaussian noise channel. Using an analytical approach, the impact of Av. BER performance relating the coherent BPSK system at the end of a multi-hop route versus the spatial density of sensor nodes and impulsive noise parameters A and $\Gamma$ is evaluated.

Fabrication of a SOI hall sensor using Si-wafer direct bonding technology and its characteristics (실리콘기판 직접접합기술을 이용한 SOI 홀 센서의 제작과 그 특성)

  • 정귀상
    • Electrical & Electronic Materials
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    • v.8 no.2
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    • pp.165-170
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    • 1995
  • This paper describes the fabrication and characteristics of a Si Hall sensor fabricated on a SOI (Si-on-insulator) structure. The SOI structure was formed by SDB(Si-wafer direct bonding) technology and the insulator of the SOI structure was used as the dielectrical isolation layer of a Hall sensor. The Hall voltage and sensitivity of the implemented SDB SOI Hall sensors showed good linearity with respect to the applied magnetic flux density and supplied current. The product sensitivity of the SDB SOI Hall sensor was average 600V/A.T and its value has been increased up to 3 times compared to that of bulk Si with buried layer of 10.mu.m. Moreover, this sensor can be used at high-temperature, high-radiation and in corrosive environments.

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