• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.10
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• pp.80-86
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• 2014

A low-noise readout circuit is studied for 2-D capacitive microbolometer focal plane arrays (FPAs). In spite of the merits of the integration method, a simple and effective pixelwise readout circuit without integration is used for input circuit because of a small pixel size and narrow noise bandwidth. To reduce the power consumption and the kT/C noise, which is the dominant noise of the capacitive microbolometer FPAs with small capacitance, a new correlated double sampling (CDS) is used for columnwise circuit. The proposed circuit has been designed using a $0.35-{\mu}m$ 2-poly 4-metal CMOS process for a microbolometer array with a pixel size of $50{\mu}m{\times}50{\mu}m$. The proposed circuit effectively reduces the kT/C noise and the other low-frequency noise of microbolometer, and the noise characteristics of the fabricated chip have been verified by measurements. The rms noise voltage of the proposed circuit is reduced from 30 % to 55 % compared to that of the simple readout input circuit, and the noise equivalent temperature difference (NETD) of the proposed circuit is very low value of 21.5 mK.

• The Korean Journal of Community Living Science
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• v.13 no.2
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• pp.37-51
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• 2002

This study was performed to investigate the degree of different stresses and to search the influence of food habit and nutrient intakes at stress situation in university students and secondary school teachers. The data was collected by questionnaire method and searched nutrient intakes by 24 hours recall. The subjects were 282 students and 152 high school teacher in Kyunggi do. Physical status was no difference with two groups. Energy intake of teachers was lower than that of students, but the intakes of vitamin A and C were high in teachers' group. The university students had more stress situation than teachers in almost kind of stresses except overload stress. Self-diagnosed dietary habits were better in the group of teacher. Especially smoke and alcohol drink behavior were correlated with nutrient intakes in male teachers and students. The quantity of nutrient of nutrient intakes was correlated with different kind of stress. The stress of life event was correlated with the intakes of carbohydrate, minerals, thiamin and riboflavin, and the deprivation was with iron and vitamin A in teachers' group. The intake of almost nutrients was correlated with the stress of noise in students' group. By the analysis of stepwise multiple regression, although the $R^2$ values were very low, vitamin C intake was influenced in the factor at the stress of life events($R^2$=0.025), self-efface($R^2$=0.030) and noise($R^2$=0.020), thiamin was at food induced stress ($R^2$=0.021) and vitamin A was at the stress of type A behavior($R^2$=0.022) and anxiety response($R^2$=0.014). Therefore, we could concluded that different kind of stresses were influenced in dietary behavior and nutrient intakes. More research would be needed at the aspects of health promotion in the stressful situation of modern society.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.154-159
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• 1998

In this paper, BLDC spindle motor is designed using CAE/CAT to reduce structural vibration. Motor is modeled and analyzed using a finite element analysis (FEA) program and correlated to the results of modal test. Design sensitivity analysis (DSA) of frequency is carried out and validated by the modal test of modified motor manufactured. This study shows that simulation-based design can improve quality with reduced development time.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.439-443
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• 2001

The steering wheel vibrations such as shimmy, brake judder and shake are affected by the vibration characters of steering and suspension. For the analysis of shimmy, nonuniformities of tire can be considered the major sources. This study investigates unbalances and uniformities of tire in which the lateral force variation is highly correlated with shimmy. The hardness of suspension bushes can be modified to change the dynamic behavior of suspension that is effective to reduce the sensitivity of shimmy.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.1039-1042
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• 2002

SMD(Surface Mounting Device) which mounts electronic components as IC-Chips on PCB automatically, produces a large dynamic force and vibration. The unwanted vibrations in SMD degrade the performance of the precision device and it is the major obstacle to limit its speed for mounting. This study investigated the vibration analysis of a typical SMD to predict the natural frequencies and mode shapes. To validate the finite element analysis of SMD, the FE result was compared with that of ODS measurements. It was shown that the predicted results were well correlated with the experimental modal parameters.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.5
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• pp.455-463
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• 2003

Adaptive noise cancellation techniques are ideally suitable for reducing spatially varying noise due to the grain structure of material in ultrasonic nondestructive evaluation. Grain noises have an un-correlation property, while flaw echoes are correlated. Thus, adaptive filtering algorithms use the correlation properties of signals to enhance the signal-to-noise ratio (SNR) of the output signal. In this paper, a multi-stage adaptive noise cancellation (MANC) method using adaptive least mean square error (LMSE) filter for enhancing flaw detection in ultrasonic signals is proposed.

• Journal of Convergence for Information Technology
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• v.11 no.9
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• pp.1-7
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• 2021

Since recently only an auto-correlated superposition coding (SC) scheme for non-orthogonal multiple access(NOMA) has been investigated, this paper proposes a cross-correlated SC scheme for NOMA. First, we derive the closed-form expression of the sum rate of the proposed cross-correlated SC scheme. Then, numerical analyses demonstrate that the sum rate of the proposed cross-correlated SC scheme is larger than that of the conventional auto-correlated SC scheme. We also show that for the stronger channel gain user, the signal-to-noise ratio (SNR) gain of the proposed cross-correlated SC scheme is about 15, compared with the conventional auto-correlated SC scheme. As a result, the proposed cross-correlated SC scheme could be a promising technology for 6G ultra-reliable low-latency communications (URLLC).

• The Journal of the Acoustical Society of Korea
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• v.15 no.2E
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• pp.39-44
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• 1996

The performance of two-channel adaptive noise canceller is ofter degraded by the weights perturbation due to the speech signal. In this paper, an adaptive noise canceller employing a speech detector and two adaptation algorithms which are switched according to the speech detector is proposed. When highly correlated speech signal is detected, the tap weights of the adaptive filter are adapted by the sign algorithm. On the other hand, the weights are adapted by the NLMS algorithm when silence is detected or when the characteristics of the noise propagation channel is changed. The employed speech detector utilizes the power ratio of the input and the output of an adaptive linear prediction-error filter. According to the computer simulation, the proposed method yields better performance than conventional ones.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.8
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• pp.364-373
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• 2001

The gear whine noise of vehicle transmission is directly correlated tilth the gear transmission error of mating gear The object of this study is to build up the synthesized countermeasure for the reduction of gear whine noire of vehicle transmission by developing the program which can be used to analyze and predict the vibrational characteristics caused by gear transmission error of mating gears of vehicle transmission. The developed mathematical models on the elements of transmission, for example, helical gear pairs, bearings and shafts are used and the modeling of the excitation forces are developed by the gear transmission error of mating gear which is defined by the amount of the elastic deformation of gear tooth & shaft and gear profile & lead errors. The mathematical system model of vehicle transmission developed by the substructure synthesis method Is also verified by the experiments.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.12
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• pp.1241-1248
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• 2004

This paper presents an acoustic source localization technique on 2D cavity model in flow using a phased microphone array. Investigation was performed on cavity flows of open and closed types. The source distributions on 2D cavity flow were investigated in an anechoic open-jet wind tunnel. The array of microphones was placed outside the flow to measure the far field acoustic signals. The optimum sensor placement was decided by varying the relative location of the microphones to improve the spatial resolution. Pressure transducers were flush-mounted on the cavity surface to measure the near-filed pressures. It is shown that the propagated far field acoustic pressures are closely correlated to the near-field pressures and their spectral contents are affected by the cavity parameter L/D.