• Korean Journal of School Psychology
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• v.16 no.2
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• pp.207-230
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• 2019

This study examined the effect of Attention Feedback Awareness and Control Training(A-FACT) on attention bias and generalized anxiety symptoms in college students. A total of 31 college students with at least 10 points on the Generalized Anxiety Disorder 7-item (GAD-7) scale or at least 56 points on the Korean version of the Penn State Worry Questionnaire (K-PSWQ) with attention bias were randomly assigned to one of three groups: A-FACT( n = 11), Attention Bias Modification (ABM)(n = 10) and Active Placebo Control (APC)(n = 10). Participants in A-FACT group received real-time feedback on attention bias based on their Baseline Neutral Response time(BNR) during A-FACT using a dot probe task. Participants in the ABM group received standard ABM, and those in the APC performed a dot probe task that they were informed was a program to reduce attention bias, but feedback was not provided. A total of eight sessions was conducted twice a week over a 4-week period. After every two sessions, GAD-7, K-PSWQ and K-STAI were rated. The effect of attention bias modification training was rated by changes in the Attention Bias Score(ABS), and in GAD-7, K-PSWQ and K-STAI scores. The results of repeated measure ANOVA indicated that the A-FACT group showed a significant decrease in ABS as well as in GAD-7, K-PSWQ and K-STAI scores compared to the other groups. Current results suggest that self-regulatory control of attention, that is, recognition of bias through feedback in A-FACT, may be effective in alleviating attention bias and generalized anxiety symptoms by recognizing bias through feedback on bias in attention bias modification training.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.7
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• pp.978-983
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• 2015

This paper presents Frequency Bias setting for the adequate AGC(Automatic Generator Control) operation based on the frequency response of power system in Korea. AGC frequency control recovers the frequency up to 60Hz following a primary control when the frequency suddenly drops due to a fault in power system. AGC can compensate an appropriate amount of generation by calculating ACE(Are Control Error) from the frequency deviation with the AGC frequency bias set from the actual frequency response in power systems. An appropriateness of the proposed AGC bias setting is verified through case studies employing the simulation model.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.317-320
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• 2000

In this paper, a 0.5W, 2GHz high-efficiency class A power amplifier using the dynamic bias control is proposed. First of all, the drain bias control amplifier is analyzed theoretically and designed with commercial devices. Simulation results show that the proposed amplifier has a significant improved efficiency, compared to fixed bias power amplifier.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.4
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• pp.254-260
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• 2000

This paper deals with the development of fault tolerant control for a nonlinear boiler system with noise and disturbance. The MCMBPC(Multivariable Constrained Model Based Predictive Control) is adopted for the control of the specific boiler turbin model. The fault detection and diagnosis are accomplished with the Kalman filter and two bias estimators. Once a fault is detected, two Bias estimators are driven to estimate the fault and to discriminate Process fault and sensor fault. In this paper, a fault tolerant control scheme combining MCMBPC with a fault compensation method based on the bias estimator is proposed. The proposed scheme has been applied to the nonlinear boiler system and shown a satisfactory performance through some simulations.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.5
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• pp.198-201
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• 2005

Carbon nanofibers were formed on silicon substrate which was applied by negative direct current (DC) bias voltage using microwave plasma-enhanced chemical vapor deposition method. Formation of carbon nanofibers were varied according to the variation of the applied bias voltage. At -250 V, we found that the growth direction of carbon nanofibers followed the applied direction of the bias voltage. Based on these results, we suggest one of the possible techniques to control the growth direction of the carbon nanofibers.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.43-46
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• 2012

In this paper, high efficiency power amplifier is implemented with high gain amplifier. Two-stage amplifier using adaptive bias control circuit improve efficiency at low input power. Fixed bias circuit and adaptive bias circuit both have about 76 % efficiency at maximum power level. However amplifier using an adaptive bias control circuit has 70 % at 6 dBm input power level when the amplifier using fixed bias circuit has 50%. The proposed power amplifier using the adaptive bias control circuit can have high efficiency at lower power level.

• Journal of the Korean Data and Information Science Society
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• v.25 no.5
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• pp.1127-1135
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• 2014

Genome-wide association studies (GWAS) are designed to discover genetic variants such as single nucleotide polymorphisms (SNPs) that are associated with human complex traits. Although there is an increasing interest in the application of GWAS methodologies to population-based cohorts, many published GWAS have adopted a case-control design, which raise an issue related to a sampling bias of both case and control samples. Because of unequal selection probabilities between cases and controls, the samples are not representative of the population that they are purported to represent. Therefore, non-random sampling in case-control study can potentially lead to inconsistent and biased estimates of SNP-trait associations. In this paper, we proposed inverse-probability of sampling weights based on disease prevalence to eliminate a case-control sampling bias in estimation and testing for association between SNPs and quantitative traits. We apply the proposed method to a data from the Korea Association Resource project and show that the standard estimators applied to the weighted data yield unbiased estimates.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.963-966
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• 1999

This Paper describes the design of high speed and low power comparator based on the feed forward bias control. Major building blocks of this comparator are composed of input offset canceling circuit and feed forward bias control circuit. The usual offset canceling circuit cancels the offset voltages by storing them in capacitors using MOS switches, The comparator of this paper employs the bias control circuit which generates bias signal from the input signal. The bias signal is applied to the capacitors and keeps the transfer of chares in the capacitors in the minimal amount, therefore making the comparator operate in stable condition and reduce decision time. The comparator in this form has very samll area and power dissipation. Maximum sampling rate is 200 Ms/sec. The comparator is designed in 0.65${\mu}{\textrm}{m}$ technology and the offset is less than 0.5㎷.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.3
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• pp.326-333
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• 2015

This paper reports an adaptive positive feedback bias control technique for operational transconductance amplifiers to adjust the bias current based on the output current monitored by a current replica circuit. This technique enables operational transconductance amplifiers to quickly adapt their power consumption to various analog workloads when they are configured with negative feedback. To prove the concept, a test voltage follower is fabricated in $0.5-{\mu}m$ CMOS technology. Measurement result shows that the power consumption of the test voltage follower is approximately linearly proportional to the load capacitance, the signal frequency, and the signal amplitude for sinusoidal inputs as well as square pulses.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.11
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• pp.1053-1059
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• 2013

Heading bias effects in PNS using IMUs attached to shoes are analyzed in this paper. The navigation algorithms of a single foot PNS where one IMU is attached to a foot and dual foot PNSs where two IMUs are attached to each foot are derived. Two navigation algorithms are proposed for the dual foot PNS: 1) the positions from the independent right and left foot PNSs are averaged to provide the final position, 2) the right and left foot PNSs are correlated and it provides positions of each foot. Furthermore, it is proven that two methods are equal. Using the derived navigation algorithms the effect of heading bias caused by a misalignment of the moving direction and IMU is analyzed. The analysis explains the position error of a single foot PNS is diverged while the heading bias is effectively compensated in dual foot PNSs because of the symmetry of heading biases. The experimental results confirm the analysis.