• Journal of Korea Multimedia Society
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• v.13 no.5
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• pp.641-650
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• 2010

Color image sensors (CIS) output color images through image sensors and image signal processing. Image sensors that convert light to electrical signal are divided into CMOS image sensor and CCD image sensor according to transferring method of signal charge. In general, a CIS has RGB output signals from tri-stimulus XYZ of the scene through image signal processing. This paper presents an adaptive colorimetric analysis method to obtain chromaticity and luminance using CIS under various environments. An image sensor for the use of colorimeter is characterized based on the CIE standard colorimetric observer. We use the method of least squares to derive a colorimetric characterization matrix between camera RGB output signals and CIE XYZ tristimulus values. We first survey the camera characterization in the standard environment then derive a SGL(shutter-gain-level) function which is relationship between luminance and auto exposure (AE) characteristic of CIS, and read the status of an AWB(auto white balance) function. Then we can apply CIS to measure luminance and chromaticity from camera outputs and AE resister values without any preprocessing. Camera RGB outputs, register values, and camera photoelectric characteristic are used to analyze the colorimetric results for real scenes such as chromaticity and luminance. Experimental results show that the proposed method is valid in the measuring performance. The proposed method can apply to various fields like surveillant systems of the display or security systems.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.4
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• pp.338-347
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• 2021

In this paper, the beta-ray sensor circuit used in the true random number generator was designed using DB HiTek's 0.18㎛ CMOS process. The CSA circuit proposed a circuit having a function of selecting a PMOS feedback resistor and an NMOS feedback resistor, and a function of selecting a feedback capacitor of 50fF and 100fF. And for the pulse shaper circuit, a CR-RC2 pulse shaper circuit using a non-inverting amplifier was used. Since the OPAMP circuit used in this paper uses single power instead of dual power, we proposed a circuit in which the resistor of the CR circuit and one node of the capacitor of the RC circuit are connected to VCOM instead of GND. And since the output signal of the pulse shaper does not increase monotonically, even if the output signal of the comparator circuit generates multiple consecutive pulses, the monostable multivibrator circuit is used to prevent signal distortion. In addition, the CSA input terminal, VIN, and the beta-ray sensor output terminal are placed on the top and bottom of the silicon chip to reduce capacitive coupling noise between PCB traces.

• Smart Structures and Systems
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• v.16 no.5
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• pp.759-780
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• 2015

Based on the theory of piezoelasticity, the static performance of a piezoelectric bilayer cantilever fully covered with electrodes on the upper and lower surfaces is studied. Three models are considered, i.e., the sensor model, the driving displacement model and the blocking force model. By establishing suitable boundary conditions and proposing an appropriate Airy stress function, the exact solutions for piezoelectric bilayer cantilevers are obtained, and the effect of ambient thermal excitation is taken into account. Since the layer thicknesses and material parameters are distinguished in different layers, this paper gives unified solutions for composite piezoelectric bilayer cantilevers including piezoelectric bimorph and piezoelectric heterogeneous bimorph, etc. For some special cases, the simplifications of the present results are compared with other solutions given by other researches based on one-dimensional constitutive equations, and some amendments have been found. The present investigation shows: (1) for a PZT-4 piezoelectric bimorph, the amendments of tip deflections induced by an end shear force, an end moment or an external voltage are about 19.59%, 23.72% and 7.21%, respectively; (2) for a PZT-4-Al piezoelectric heterogeneous bimorph with constant layer thicknesses, the amendments of tip deflections induced by an end shear force, an end moment or an external voltage are 9.85%, 11.78% and 4.07%, respectively, and the amendments of the electrode charges induced by an end shear force or an end moment are both 1.04%; (3) for a PZT-4-Al piezoelectric heterogeneous bimorph with different layer thicknesses, the maximum amendment of tip deflection approaches 23.72%, and the maximum amendment of electrode charge approaches 31.09%. The present solutions can be used to optimize bilayer devices, and the Airy stress function can be used to study other piezoelectric cantilevers including multi-layered piezoelectric cantilevers under corresponding loads.

• Journal of Sensor Science and Technology
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• v.27 no.2
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• pp.93-98
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• 2018

In this paper, an energy-efficient 11.49-bit successive approximation register (SAR) capacitance-to-digital converter (CDC) for capacitive sensors with a figure of merit (FoM) of 31.6 pJ/conversion-step is presented. The CDC employs a SAR algorithm to obtain low power consumption and a simplified structure. The proposed circuit uses a capacitive sensing amplifier (CSA) and a dynamic latch comparator to achieve parasitic capacitance-insensitive operation. The CSA adopts a correlated double sampling (CDS) technique to reduce flicker (1/f) noise to achieve low-noise characteristics. The SAR algorithm is implemented in dual operating mode, using an 8-bit coarse programmable capacitor array in the capacitance-domain and an 8-bit R-2R digital-to-analog converter (DAC) in the charge-domain. The proposed CDC achieves a wide input capacitance range of 29.4 pF and a high resolution of 0.449 fF. The CDC is fabricated in a $0.18-{\mu}m$ 1P6M complementary metal-oxide-semiconductor (CMOS) process with an active area of 0.55 mm2. The total power consumption of the CDC is $86.4{\mu}W$ with a 1.8-V supply. The SAR CDC achieves a measured 11.49-bit resolution within a conversion time of 1.025 ms and an energy-efficiency FoM of 31.6 pJ/step.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.1
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• pp.1-9
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• 2007

3D data are in great demand for pedestrian navigation recently. For pedestrian navigation, we needs to reconstruct 3D model in detail from people's eye. In order to present spatial features in detail for pedestrian navigation, it is indispensable to develop 3D model not only in outdoor environment but also in indoor environment such as underground shopping complex. However, it is very difficult to acquire 3D data efficiently by mobile mapping without GPS. In this research, 3D shape was acquired by Laser scanner, and texture by CCD(Charge Coupled Device) sensor. Continuous changes position and attitude of sensors were measured by IMU(Inertial Measurement Unit). Moreover, IMU was corrected by relative orientation of CCD images without GPS(Global Positioning System). In conclusion, Reliable, quick, and handy method for acquiring 3D data for indoor environment is proposed by a combination of a digital camera and a laser scanner with IMU.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.1
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• pp.114-122
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• 2018

In this paper, we propose new water pressure measurement system to measure the water pressure of water pipe laid underground beneath the manhole efficiently. For this purpose, we installed water pressure sensor(IoT) which has built-in bluetooth module at valve of water pipe. The proposed system can be managed through collected data which measured at sensor and then transmitted to smart phone through bluetooth connectivity and re-transmitted to server on this system. By checking out water pressure data stored in server from remote location, the persons in charge can confirm the leakage of water pipe or propriety of water pressure in management area. By this procedure, they can detect the existence of condition of water pipe and manage water pressure of water pipe efficiently.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.577-583
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• 2014

A ship-to-ship (STS) lightering operation takes place in order to transfer cargo (e.g. crude oil or petroleum products) between an ocean-going ship and a service ship alongside it. Instrumental measurements to accurately determine the relative speeds and distances during the approach between the vessels would benefit the operational safety and efficiency. A velocity information GPS (VI-GPS) system, which uses the instantaneous velocity measures from carrier-phase Doppler measurement, has been applied in a field observation onboard a service ship (Aframax tanker) approaching a ship-to-be-lightered (VLCC) in open waters. This article proposes to apply VI-GPS as the input sensor to a guidance and decision-support system aiming to provide accurate velocity information to the officer in charge of an STS operation. A method for precise velocity measurement using VI-GPS was described and the measurement results were compared each other with the results of Voyage Data Recorder (VDR) and VI-GPS that showed the concept of a guidance and decision-support system applying VI-GPS with the field test results during STS operations. Also, it turned out that VI-GPS has sufficient accuracy to serve as an input sensor from the field test results.

• Journal of Sensor Science and Technology
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• v.12 no.4
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• pp.191-197
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• 2003

Due to explosive increase of internet usage, broadband data transmission using optical fibers is broadly used. In order to decrease distortion during long distance transmission, the optical signal need to be restored, typically, by converting the optical signal into the electrical signal. The optical signal is converted into the electrical signal using a photo-diode, and then a clock-and-recovery (CDR) circuit is used to recover the clock and retime the data. In this study, a clock-and-data recovery circuit has been designed using a standard 1.8 V $0.18\;{\mu}m$ CMOS process. With this CDR circuit, the improved phase detector and charge pump have been utilized. Also, by using a ring oscillator, the CDR circuit can recover clock and data from broadband multi-rate data ranging between 750 Mb/s and 2.85 Gb/s.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.920-926
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• 2011

In this paper, a solar power emotional LED lightening street lamps with multi control sun tracker is presented. The proposed system has a multiple control sun tracking function and high quality emotional LED lamps. The system is designed to absorb maximum sun lights by temperature sensor and humidity sensor of control circuits. A battery charge-discharge controller is developed for high efficient usage of battery charger for utilization of new and renewal energy. An interface circuit for remote monitoring and controlling is included in the developed system. The proposed multi tracking solar power emotional LED street lamps is better than conventional systems in aspect of tracking operation and energy efficiency, and expected to be a leading model for next generation solar power street lamp system, because it is a new technology combining sun tracking solar power system and emotional lightening system.

• Applied Chemistry for Engineering
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• v.30 no.2
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• pp.186-189
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• 2019

Polypyrrole is a typical electrical conducting polymer, which has an excellent charge transport property. Cyclodextrins are a group of toxic-free and cyclic oligosaccharide molecules, capable of capturing low molecular weight chemicals. Considering these advantages, hybrid materials of polypyrrole and cyclodextrin can be used to detect hazardous compounds. Cyclodextrin molecules can accommodate toxic chemicals by the formation of host-guest complexes and generate electric signals, which are effectively delivered by polypyrrole backbone. In this study, the polypyrrole/cyclodextrin hybrid material was prepared using a facile wet method and included into a hydrogel. Subsequently, it was applied to a simple sensor system with a gold-patterned electrode for the detection of potentially hazardous material, methyl paraben. Compared with pristine polypyrrole, it was found that the polypyrrole/cyclodextrin hybrid showed an improved performance. This study can be an example of using environmentally benign conducting polymer/cyclodextrin hybrids as sensing media.