• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.8
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• pp.79-85
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• 2009

In this paper, an accurate current reference using temperature and process compensation current mirror (TPC-CM) is proposed. The temperature independent reference current is generated by summing a proportional to absolute temperature (PTAT) current and a complementary to absolute temperature (CTAT) current. However, the temperature coefficient and magnitude of the reference current are influenced by the process variation. To calibrate the process variation, the proposed TPC-CM uses two binary weighted current mirrors which control the temperature coefficient and magnitude of the reference current. After the PTAT and CTAT current is measured, the switch codes of the TPC-CM is fixed in order that the magnitude of reference current is independent to temperature. And, the codes are stored in the non-volatile memory. In the simulation, the effect of the process variation is reduced to 0.52% from 19.7% after the calibration using a TPC-CM in chip-by-chip. A current reference chip is fabricated with a 3.3V 0.35um CMOS process. The measured calibrated reference current has 0.42% variation for $20^{\circ}$C${\sim}$100$^{\circ}$C.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.251-256
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• 2004

A stable reference voltage generator is necessary to the infrared image signal readout circuit(ROIC) to improve noise characteristics in comparison with signals originated from infrared devices, that is, to gain good images. In this study, bandgap reference circuit operating at cryogenic temperature of 77K for Infrared image ROIC(readout integrated circuit) was propose. Most of bandgap reference circuits which are presented so far operate at room temperature, and they are not suitable for infrared image ROIC operating at liquid nitrogen temperature, 77K. To design bandgap reference circuit operating at cryogenic temperature, the parameter characteristics of used devices as temperature change are seen, and then bandgap reference circuit is proposed with considering such characteristics. It demonstrates practical use possibility through taking measurements and estimations.

• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.215-218
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• 2009

In this paper, temperature stable current and voltage references using simple CMOS bias circuit are proposed. To obtain temperature stable characteristics of bias circuit a bandgap reference concept is used in a conventional circuit. The parasitic bipolar transistors or MOS transistors having different threshold voltage are required in a bandgap reference. Thereby the chip area increase or the extra CMOS process is required compared to a standard CMOS process. The proposed reference circuit can be integrated on a single chip by a standard CMOS process without the extra CMOS process. From the simulation results, the reference current variation is less than ${\pm}$0.44% over a temperature range from - $20^{\circ}C$ to $80^{\circ}C$. And the voltage variation is from - 0.02% to 0.1%.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.4
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• pp.97-103
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• 2006

A synthetic infrared image can be effectively utilized in various fields such as the recognition and tracking of targets as long as its quality is good enough to reflect the real situations. One way to improve its quality is to use the reference atmosphere which best describes atmospheric properties of regional areas. The east asian reference atmosphere has been developed to represent atmospheric properties of the east asia including Korean peninsula. However, few research has been conducted to examine the effects of this east asian reference atmosphere on the modeling and simulation. In this regard, this paper analyzes the effects of the east asian reference atmosphere on a synthetic infrared image. The research compares the atmospheric transmittance, the surface temperature, and the radiance obtained by using the east asian reference atmosphere with those of the midlatitude reference atmosphere which has been widely applied in the east asia. The results show that the differences of the atmospheric transmittance, the surface temperature, and the radiance between the east asian reference atmosphere and the midlatitude reference atmosphere are significant especially during the daytime. Therefore, it is recommended to apply the east asian reference atmosphere for generating a synthetic infrared image with targets in the east asia.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.6
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• pp.571-576
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• 2015

Temperature characteristics of supply oil in an ultra-precision hydrostatic table are largely influenced by parameter setting in an oil cooler such as the location of reference sensor and cooling temperature. In this paper, influences of the parameter setting on the temperature variation in the hydrostatic table are experimentally analyzed to suggest the guidelines for practical application. In case of using temperature of inlet oil as a reference sensor in the oil cooler, temperature rise of the supply oil is smaller and thermal settling time is faster than that of using temperature of outlet oil as a reference sensor. The experimental results also show that temperatures of table, rail and return oil can be made almost same, and thermal settling time can be decreased by setting cooling temperature in the oil cooler to be lower than atmospheric temperature.

• 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.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.635-636
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• 2006

A self-biased CMOS current reference is described which provides supply and temperature independent bias current. The supply independency is obtained by subtracting two bias currents which have the same supply dependency. Unlike the conventional self-bias CMOS current reference, excellent supply independency can be obtained even with the minimum channel length devices and thus smaller area implementation becomes possible. The supply independent bias current is then applied to a temperature compensating circuit and as a result supply and temperature independent bias current is obtained. The current reference has been implemented in a $0.25{\mu}m$ standard CMOS technology. The active silicon area is only $45{\mu}m{\times}45{\mu}m$. The simulated temperature coefficient is 64ppm/$^{\circ}C$ in temperature range between $0^{\circ}C$ and $120^{\circ}C$. Supply voltage can be as low as 1.3V and the supply dependency of the current reference is measured to be smaller than 4500ppm/V. While providing $10.25{\mu}A$ output current, the current reference consumes $160{\mu}W$.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.1077-1080
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• 1998

In this paper, a simple low-power current-mode CMOS wotage reference circuit is proposed. The reference circuit of enhancement-mode MOS transistors and resistors. Temperature compensation is made by adding a current component proportional to a thermal voltage to a current component proportional to a threshold voltage. The designed circuit has been simulated using a $0.65\mu\textrm{m}$ n-well CMOS process parameters. The simulation results show that the reference circuit has a temperature coefficient less than $7.8ppm/^{\circ}C$ and a power-supply(VDD) coefficient less than 0.079%/V for a temperature range from $-30^{\circ}C$ to $130^{\circ}C$ and a VDD range from 4.0V to 12V. The power consumption is 105㎼ for VDD=5V and $T=30^{\circ}C.$ The proposed reference circuit can be designed to generate a wide range of reference voltages owing to its current-mode operation.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.1
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• pp.95-105
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• 2019

Evapotranpiration (ET) is one of the important factor in Hydrological cycle and irrigation planning. In this study, temperature-based artificial neural network (ANN) model for daily reference crop ET estimation was developed and compared with reference crop evapotranpiration ($ET_0$) from FAO-56 Penman-Monteith method (FAO-56 PM) and parameter regionalized Hargreaves method. The ANN model was trained and tested for 10 weather stations (5 inland stations and 5 costal stations) and two input climate factors, maximum temperature ($T_{max}$), minimum temperature ($T_{min}$), and extraterrestrial radiation (RA) were used for training and validation of temperature-based ANN model. Monthly reference ET by the ANN model also compared with parameter regionalized Hargreaves method for ANN model applicability evaluation. The ANN model evapotranspiration demonstrated more accordance to FAO-56 PM evapotranspiration than the $ET_0$ from parameter regionalized Hargreaves method(R-Hargreaves). The results of this study proposed that daily reference crop ET estimated by the ANN model could be used in the condition of no sufficient climate data.

• Korean Journal of Clinical Laboratory Science
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• v.36 no.1
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• pp.33-37
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• 2004

In order to study the effect of temperature of denaturation, annealing and extension and cycles on amplification of DNA by PCR method, We isolated the hepatitis B virus DNA from hepatitis B patient blood and compared the density of DNA amplified by Reference PCR Program (denaturation at $94^{\circ}C$ for 30 sec., annealing at $60^{\circ}C$ for 1 min., extension at $72^{\circ}C$ for 1 min., holding at $72^{\circ}C$ for 5min., 30 cycles) that is usually used in laboratory to the density of DNA amplified by PCR program changed only the denaturation temperature or annealing temperature or extension temperature. We amplified about 341bp of hepatitis B virus DNA by Reference PCR Program from hepatitis patient blood, but the DNAs denatured at $72^{\circ}C$ or $60^{\circ}C$ were not detectable on photoradiography film. The DNA amplified at $37^{\circ}C$ of annealing temperature was not detectable, but the DNA annealed at $72^{\circ}C$ was detectable the lower density of DNA than the DNA amplified by Reference PCR Program. Each DNA amplified by PCR program changed only the extension temperature to $37^{\circ}C$ or $60^{\circ}C$ was almost same density as DNA amplified by Reference PCR Program. We compared the density of hepatitis B virus DNA amplified by Reference PCR Program for 30 cycles, 20 cycles, 10 cycles, and 5 cycles. The DNA cycled for 20 cycles was not amplified well as cycled for 30 cycles, but the DNA was detectable on the photoradiography film. The DNAs amplified for 10 cycles or 5 cycles were not detectable on photoradiorgaphy film. The concentration of hepatitis B virus DNA amplified in Reference PCR condition for 30 cycles, 20 cycles, 10 cycles, and 5 cycles were $72{\mu}g/m{\ell}$, $83{\times}10^{-3}{\mu}g/m{\ell}$, $27{\times}10^{-6}{\mu}g/m{\ell}$, and nondetectable, respectively.