• Korean Journal of Materials Research
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• v.16 no.2
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• pp.129-136
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• 2006

In order to get basic information on the reference electrode material for the long life Al concentration sensor in zinc galvanizing melt, the workability and stability of fluorine potential cell with $CaF_2$ single crystal electrolyte were examined carefully at constant temperature for six kinds of reference materials (Zn, Sn, Cd, Bi, Pb, Al-Sn alloy + fluorides). Good workability and stability of the sensor were found in sensor with $Bi+BiF_3$ reference electrode. The Al sensor with $Bi+BiF_3$ reference electrode was assembled and was tested in Zn-Al melt with different Al concentration. The EMF was changed rapidly with the change of Al concentration and was stabilized in a short time. Thus the response of EMF was satisfactory for $CaF_2$ sensor. The correlationship between EMF from the sensor and logarithm of Al concentration has been derived from the least square regression method. E/mV=57.515log[wt% Al]+1883.3 R=0.9717 ($0.013{\leq}[wt% Al]{\leq}0.984$) The EMF from Al sensor was increased linearly against logarithm of [wt% Al]. The fluorine potential of Zn-Al melt was also calculated to be in the range of $10^{-60}{\sim}10^{-61}$ Pa for the present experiemental condition.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.9
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• pp.13-19
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• 2008

Time synchronization of nodes in sensor network synchronizes sensor nodes to one time clock. This is very essential in sensor networks so that the information collected and reported from the sensor nodes becomes meaningful. If sensor nodes are not synchronized, disaster report with time information can be wrong analyzed and this may lead to big calamity. With the limitation of battery and computing power, time synchronization algorithm imported in sensor nodes has to be as simple as it doesn't need big complexity, nor generates many synchronization messages. To reduce the synchronization error, hop count should be kept small between reference node to initiate synchronization and sensor nodes to be synchronized. Therefore, multiple reference nodes are used instead of single reference node. The use of multiple reference nodes introduce the requirement of synchronization among reference nodes in the network. Several algorithms have been proposed till now, but the synchronization among reference nodes are not well considered. This paper proposes improved time synchronization for sensor networks by synchronizing multiple reference nodes inside the network. Through simulation, we validated the effects of new algorithm.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.8 no.3
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• pp.152-156
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• 2009

This paper designs and implements wake up module for WBAN/USN sensor node which is using dynamic reference voltage demodulation circuit. When a comparator is used in a system for detecting received voltage level, comparator must have a reference voltage. However, the reference voltage is fixed, the system can communicate only a few range because received voltage level is changing widely due to distance of the wireless sensor nodes. Therefore, the proposed wake up module employs a dynamic reference voltage demodulation circuit for increasing communication range.

• Journal of Sensor Science and Technology
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• v.19 no.6
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• pp.483-489
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• 2010

Display quality depends on panel temperatures. To compensate it, temperature sensor was integrated on the panel. The conventional temperature sensor integrated on the panel needs external reference resistor. Since the resistance of external resistor can vary according to the variation of the environment temperature, the conventional temperature sensor can make error in temperature sensing. The environmental temperatures can change by the back light unit, driving circuits or chips. In this paper, we proposed a integrated temperature sensor on display panel which does not need external reference resister. Instead of external reference resistor, we used two materials which have different temperature coefficient in resistivity. They are connected serially and the output voltage was measured at the point of connection with the applied voltage to both ends. The proposed sensor was fabricated with indium tin oxide(ITO), and Mo metal electrode temperature sensor which were connected serially. We verified the temperature senor by the measurements of sensitivity, lineality, hysteresis, repeatability, stability, and accuracy.

• Journal of Sensor Science and Technology
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• v.26 no.1
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• pp.28-34
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• 2017

An NIR grism Si optical area sensor spectrometer with in-band reference wavelength is designed and fabricated. It is composed of a transmission type diffraction grating (spatial density 300 line/mm), a rectangular N-BK7 prism (apex angle 30 degree), NIR filter(cutoff wavelength 720 nm), an imaging convex lens(focal length 50 mm F1.8) and an IR modified DSLR camera (Canon EOS40D) of Si optical area sensor ($3,888{\times}2,592$ pixels, pixel size $5.710{\mu}m$). "In-band reference wavelength function" is implemented using non-dispersive 0th diffraction order optical beam. The NIR grism spectrometer is tested in a laboratory using a halogen lamp and a Neon lamp. And the spectrometer is used in an astronomy field for obtaining the planet Jupiter NIR spectrum. In-band reference wavelength i.e. un-deviation wavelength is 846 nm, an wavelength resolution is 0.3027 nm/pixel, an wavelength resolving power is 2,794 and an wavelength range is 650~1,000 nm.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.12
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• pp.550-557
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• 2006

This paper proposes a dry-type surface myoelectric sensor for the myoelectric hand prosthesis. The designed surface myoelectric sensor is composed of skin interface and processing circuits. The skin interface has one reference and two input electrodes, and the reference electrode is located in the center of two input electrodes. In this paper is proposed two types of sensors with the circle- and bar-shaped reference electrode, but all input electrodes are the bar-shaped. The metal material of the electrodes is the stainless steel (SUS440) that endures sweat and wet conditions. Considering the conduction velocity and the median frequency of the myoelectric signal, the inter-electrode distance (IED) between two input electrodes as 18mm, 20mm, and 22mm is selected. The signal processing circuit consists of a differential amplifier with a band pass filter, a band rejection filter for rejecting 60Hz power-line noise, amplifiers, and a mean absolute value(MAV) circuit. Using SUS440, six prototype skin interface with different reference electrode shape and IED is fabricated, and their output characteristics are evaluated by output signal obtained from the forearm of a healthy subject. The experimental results show that the skin interface with parallel bar shape and the 18mm IED has a good output characteristics. The fabricated dry-type surface myoelectric sensor is evaluated for the upper-limb amputee.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.2
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• pp.119-122
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• 2009

As infrared light radiates, the CMOS Readout IC (ROIC) for the microbolometer typed infrared sensor detects voltage or current which is caused by the variation of resistance in the bolometer sensor. A serious problem we may have in designing the ROIC is the value of bolometer and reference resistors will be changed due to process variation. Since each pixel does not have the same value of resistance, fixed pattern noise problems happen during the sensor operations. In this paper, we propose a novel technique to compensate the fluctuation of reference resistance with taking account of process variation. By using a comparator and a cross coupled latch, we will make the value of reference resistor same as the bolometer's.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1268-1271
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• 2005

This paper proposes a compact-sized surface myoelectric sensor for myoelectric hand prosthesis. To fit the surface myoelectric sensor in the socket of the myoelectric hand prosthesis, the sensor should be a compact size. The surface myoelectric sensor is composed of a skin interface and a single processing circuit that are mounted on a single package. Since the skin interface has one reference and two input electrodes, and the reference electrode is located in middle of two input electrodes, we propose two types of sensors with the circle- and bar-shaped reference electrode, but all input electrodes are the bar-shaped. The metal material used for the electrodes is the stainless steel (SUS440) that endures sweat and wet conditions. Considering conduction velocity and median frequency of the myoelectric signal, we select the inter-electrode distance (IED) between two input electrodes as 18mm, 20mm, and 22 mm. The signal processing circuit consists of a differential amplifier with band pass filter, a band rejection filter for rejecting 60Hz power-line noise, amplifiers, and a mean absolute value circuit. We evaluate the proposed sensor from the output characteristics according to the IED and the shape of the reference electrode. From the experimental results we show the surface myoelectric sensor with the 18mm IED and the bar-shaped reference electrode is suitable for the myoelectric hand prosthesis.

• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.1131-1142
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• 2018

The autonomous vehicles are being developed and operated widely because of the advantages of reducing the traffic accident and saving time and cost for driving. The vehicle localization is an essential component for autonomous vehicle operation. In this paper, localization algorithm based on sensor fusion is developed for cost-effective localization using in-vehicle sensors, GNSS, an image sensor and reference images that made in advance. Information of the reference images can overcome the limitation of the low positioning accuracy that occurs when only the sensor information is used. And it also can acquire estimated result of stable position even if the car is located in the satellite signal blockage area. The particle filter is used for sensor fusion that can reflect various probability density distributions of individual sensors. For evaluating the performance of the algorithm, a data acquisition system was built and the driving data and the reference image data were acquired. Finally, we can verify that the vehicle positioning can be performed with an accuracy of about 0.7 m when the route image and the reference image information are integrated with the route path having a relatively large error by the satellite sensor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.148-149
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• 2008

As infrared light is radiated, the CMOS Readout IC (ROIC) for the microbolometer type infrared sensor detects voltage or current when the resistance value in the bolometer sensor varies. One of the serious problems in designing the ROIC is that resistances in the bolometer and reference resistor have process variation. This means that each pixel does not have the same resistance, causing serious fixed pattern noise problems in sensor operations. In this paper, Reference resistor compensation technique was proposed. This technique is to compensate the reference resistance considering the process variation, and it has the same reference resistance value as a bolometer cell resistance by using a comparator and a cross coupled latch.