• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1085-1088
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• 2003

In this work, we fabricated a gas-sensing device based on porous silicon(PS), and its I-V and C-V properties were investigated for sensing alcohol vapor. The structure of the sensor consists of thin Au/Oxidized porous silicon/porous silicon/Silicon/Al, where the silicon substrate is etched anisotropically to be prepared into a membrane shape. As the result, I-V curves showed typical tunneling property, and C-V curves were shaped like those of a MIS (metal-insulator- semiconductor) capacitor, where the capacitance in accumulation was increased with alcohol vapor concentration.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1224-1226
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• 2003

Dust-storm is one of the heaviest hazardous weather which frequently affects most part of northern China in spring. Satellite multi-spectral observations can provide significant information for detecting and quantitative determining the property of dust-storm . An algorithm to monitor dust-storm automatically was developed based on satellite observation. The algorithm utilizes split widows technique and spectral classification technique and also developed a new dust remote sensing product Infra -red Difference Dust Index (IDDI) proxy dust-loading dataset using GMS-5.

• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.159-164
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• 2021

As the attachable-type wearable devices have received considerable interests, the need for the development of high-performance electrode materials of fabric or textiles type is emerging. In this study, we demonstrated the electrochemical property of CNT fibers electrode as a flexible electrode material and its non-enzymatic glucose sensing performance. Surface morphology of CNT fibers was observed by SEM. And the electrochemical characteristics were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. The CNT fibers based sensor exhibited improved sensing performances such as high sensitivity, a wide linear range, and low detection limit due to improved electrochemical properties such as low capacitive current, good electrochemical activity by efficient direct electron transfer between the redox species and the electrode interface. Therefore, this study is expected to be used as a basic research for the development of high performance flexible electrode materials based on CNT fibers.

• Computers and Concrete
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• v.6 no.3
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• pp.225-234
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• 2009

Dredged silt from reservoirs in southern Taiwan was sintered to make lightweight aggregates (LWA), which were then used to produce lightweight aggregate concrete (LWAC).This study aimed to assess the compressive strength and homogeneity of LWAC using ultrasonic-echo sensing. Concrete specimens were prepared using aggregates of four different particle density, namely 800, 1100, 1300 and 2650 kg/$m^3$. The LWAC specimens were cylindrical and a square wall with core specimens drilled. Besides compressive strength test, ultrasonic-echo sensing was employed to examine the ultrasonic pulse velocity and homogeneity of the wall specimens and to explore the relationship between compressive strength and ultrasonic pulse velocity. Results show that LWA, due to its lower relative density, causes bloating, thus resulting in uneven distribution of aggregates and poor homogeneity. LWAC mixtures using LWA of particle density 1300 kg/$m^3$ show the most even distribution of aggregates and hence best homogeneity as well as highest compressive strength of 63.5 MPa. In addition, measurements obtained using ultrasonic-echo sensing and traditional ultrasonic method show little difference, supporting that ultrasonic-echo sensing can indeed perform non-destructive, fast and accurate assessment of LWAC homogeneity.

• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.63-68
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• 2014

This paper proposed a novel compressed sensing (CS) technique for an efficient video transmission of multi-copter. The proposed scheme is focused on reduction of the amount of data based on CS technology. First, we describe basic principle of Spectrum sensing. And then we compare AMP(Approximate Message Passing) with CoSaMP(Compressive Sampling Matched Pursuit) through mathematical analysis and simulation results. They are evaluated in terms of calculation time and complexity, then the promising algorithm is suggestd for multicopter operation. The result of experiment in this paper shows that AMP algorithm is more efficient than CoSaMP algorithm when it comes to calculation time and image error probability.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1278-1280
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• 1995

A probe type fiber-optic sensing techique for electric current measurement is applied in this paper. The technique is based on the Faraday effect which meaning is that polarization state of light is rotated by magnetic field. In experiment, test wire is located at inside and outside of the probe to be measured. The experimental results prove not only linear property, but also polarization rotation property according to the distance from outside of probe.

• Korean Journal of Materials Research
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• v.11 no.7
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• pp.599-602
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• 2001

In this study, we fabricated chemically polymerized PPy and PANi films with different selectivity by controlling dedoping time. And the sensing properties and mechanism of VOCs adsorption to conducting polymers were investigated. Thin sensor had higher sensitivity compared to thick one, and dedoped sensor for 1-minute highest sensitivity. Upon gas absorption, polypyrrole exhibited positive sensitivity while polyaniline had negative sensitivity. PPy film show hydrophilic property and PANi film show hydrophobic property. After the gas absorption, the sensitivity increased as a function of polarity of absorbed molecules. These behaviors are due to the polar molecules absorbed with the movable polaron or free carrier, and then it interrupt or generate the movement of polaron and carrier, and then it changes the conductivity of polymer. We found that conducting polymer sensors are very sensitive to the difference in polarity of gas molecules.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.4
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• pp.310-318
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• 2015

In this paper, dual-port eFuse OTP (one-time programmable) memory cells with smaller cell sizes are used, a single VREF (reference voltage) is used in the designed eFuse OTP IP (intellectual property), and a BL (bit-line) sensing circuit using a S/A (sense amplifier) based D F/F is proposed. With this proposed sensing technique, the read current can be reduced to 3.887mA from 6.399mA. In addition, the sensing resistances of a programmed eFuse cell in the program-verify-read and read mode are also reduced to $9k{\Omega}$ and $5k{\Omega}$ due to the analog sensing. The layout size of the designed 32-bit eFuse OTP memory is $187.845{\mu}m{\times}113.180{\mu}m$ ($=0.0213{\mu}m2$), which is confirmed to be a small-area implementation.

• Applied Chemistry for Engineering
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• v.25 no.2
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• pp.193-197
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• 2014

The electrode for gas sensor was prepared by using pitch-based activated carbon fibers and polyvinyl alcohol (PVA) to investigate the toxic gas sensing characteristics. The physicochemical properties of activated carbon fibers electrode for gas sensor were analyzed with SEM and BET. Toxic gases sensing property of the electrode was also identified by different toxic gases such as $NH_3$, NO and $CO_2$. The specific surface area of activated carbon fibers electrode for gas sensor was decreased by 33% owing to PVA used as a binder compared with the activated carbon fibers. However, its pore size distribution of the ACF electrode was not greatly influenced by PVA. The activated carbon fibers electrode for gas sensor responded to toxic gases by electron hopping unlike semiconductor based gas sensors. In this study, activated carbon fibers electrode was decreased to 7.5% in resistance for the NH3 gas of the 100 ppm concentration and its $NH_3$ gas sensing property was confirmed the most excellent compared with other toxic gases.

• Journal of Korea Multimedia Society
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• v.19 no.2
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• pp.200-208
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• 2016

Compressed sensing is a signal processing technique for efficiently acquiring and reconstructing in an under-sampled (i.e., under Nyquist rate) representation. A block compressed sensing with projected Landweber (BCS-SPL) framework is most widely known, but, it has high computational complexity at decoder side. In this paper, by introducing adaptive exit criteria instead of fixed exit criteria to SPL framework, an effective fast algorithm is designed in such a way that it can utilize efficiently the sparsity property in DCT coefficients during the iterative thresholding process. Experimental results show that the proposed algorithm results in the significant reduction of the decoding time, while providing better visual qualities than conventional algorithm.