• Journal of Korean Society for Quality Management
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• v.16 no.1
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• pp.49-58
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• 1988

When a question in a sample survey is sensitive or highly personal, respondents may prefer not to give truthful answers. To eliminate the resulting evasive answer bias Warner suggested a randomized response model. In this paper, a modification of Warner's method is presented and compared with Warner's method. The relation between this modified method and an unrelated question method is also discussed.

• Journal of the Korean Data and Information Science Society
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• v.27 no.2
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• pp.315-325
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• 2016

Thanks to the advantages of low cost and quick results, public opinion polls on election in Korea have been generally conducted by telephone survey, even though it has critical disadvantage of low response rate. In public opinion polls on election in Korea, the general method to handle nonresponses is adjusting the survey weight to estimate parameters. This study first drives mathematical expression of estimator and its bias with variance estimators with/without nonresponses in election polls in Korea. We also investigates the nonresponse rate of telephone survey on 2012 Korea presidential election. The average response rate was barely about 14.4%. In addition, we conducted a survey in April 2014 on the respondents's attitude toward telephone surveys. In the survey, the first reason for which respondents do not answer on public opinion polls on election was "feel bothered". And the aged 20s group, the most low response group, also gave the same answer. We here suggest that survey researchers motivate survey respondents, specially younger group, to participate surveys and find methods boosting response rate such as giving incentive.

• Communications for Statistical Applications and Methods
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• v.2 no.2
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• pp.243-248
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• 1995

The problem of optimal design for a nonparametric regression with binary data is considered. The aim of the statistical analysis is the estimation of a quantal response surface in two dimensions. Bias, variance and IMSE of kernel estimates are derived. The optimal design density with respect to asymptotic IMSE is constructed.

• Science of Emotion and Sensibility
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• v.22 no.4
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• pp.75-84
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• 2019

Addicts pay more attention to addiction-related cues, such as substance or behavior. And increased attention to these cues is associated with craving. Methamphetamine is the most abused drug among domestic drug offenders, with continually increasing rates of recidivism. Of the total number of reported drug offenders in the last three years, 21.1 percent have been women. Even so, research on female drug offenders is inadequate, rendering policies and fundamental data for the development of psychotherapy programs insufficient. The present study intended to investigate whether female methamphetamine addicts displayed an attention bias towards drug cues. A dot probe task was conducted on 22 female methamphetamine addicts (addiction group) and 22 non-addicts (control group). The task allowed the correct response rates and correct reaction times of the participants to be calculated according to the positioning of the drug and neutral cues. The analysis results revealed that the control group displayed no difference in correct reaction rates and correct reaction times between the drug or neutral cues. While, the addiction group showed lower correct response rate and slower response time for drug cues in comparison to neutral cues. The results of this study are significant in that it identified the attention bias characteristics toward drug cues of female methamphetamine addicts who were disconnected from drugs.

• Phonetics and Speech Sciences
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• v.4 no.3
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• pp.25-30
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• 2012

This study investigated whether native Korean listeners could use visual cues for the identification of the English consonants /b/ and /v/. Both auditory and audiovisual tokens of word minimal pairs in which the target phonemes were located in word-initial or word-medial position were used. Participants were instructed to decide which consonant they heard in $2{\times}2$ conditions: cue (audio-only, audiovisual) and location (word-initial, word-medial). Mean identification scores were significantly higher for audiovisual than audio-only condition and for word-initial than word-medial condition. Also, according to signal detection theory, sensitivity, d', and response bias, c were calculated based on both hit rates and false alarm rates. The measures showed that the higher identification rate in the audiovisual condition was related with an increase in sensitivity. There were no significant differences in response bias measures across conditions. This result suggests that native Korean speakers can use visual cues while identifying confusing non-native phonemic contrasts. Visual cues can enhance non-native speech perception.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.1 no.1
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• pp.23-31
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• 1976

When Television signal of VHF and UHF channel is retransmitted at the relay system with 6MHz Bandwidth including video and aural signals, the image is often affected with the unnatural changes of output amplitude frequency response within ttle region of dual sideband near to the carrier frequency. These phenomena are caused by the unnecessary lower sideband due to the spurious emission at the local oscillator, the nonlinear distortion in the linear amplifier, the intermoudulation distortion with the components of neighboring signal, the AM-PM conversion, and the envelope delay distortion. From the output characteristics, considering above results, the chief cause is caused by nonlinear response and has an effect on the bias states. Finally, it is confirmed that the effects on neighboring signal appear high in case of Down conversion than Up conversion and obtained the method for reducing the effects on the system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.7
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• pp.583-590
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• 2002

In this paper, a new Silicon on Insulator (SOI)-based photodetector was proposed, and its basic operation principle was explained. Fabrication steps of the detector are compatible with those of conventional SOI CMOS technology. With the proposed structure, RGB (Read, Green, Blue) which are three primary colors of light can be realized without using any organic color filters. It was shown that the characteristics of the SOI-based detector are better than those of bulk-based detector. To see the response characteristics to the green (G) among RGB, SOI and bulk NMOSFETS were fabricated using $1.5\mu m$ CMOS technology and characterized. We obtained optimum optical response characteristics at $V_{GS}=0.35 V$ in NMOSFET with threshold voltage of 0.72 V. Drain bias should be less than about 1.5 V to avoid any problem from floating body effect, since the body of the SOI NMOSFET was floated. The SOI and the bulk NMOSFETS shown maximum drain currents at the wavelengths of incident light around 550 nm and 750 nm, respectively. Therefore the SOI detector is more suitable for the G color detector.

• Communications for Statistical Applications and Methods
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• v.28 no.5
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• pp.411-424
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• 2021

Inference following two-stage adaptive designs (also known as two-stage randomization designs) with survival endpoints usually focuses on estimating and comparing survival distributions for the different treatment strategies. The aim is to identify the treatment strategy(ies) that leads to better survival of the patients. The objectives of this study were to assess the performance three commonly cited methods for estimating survival distributions in two-stage randomization designs. We review three non-parametric methods for estimating survival distributions in two-stage adaptive designs and compare their performance using simulation studies. The simulation studies show that the method based on the marginal mean model is badly affected by high censoring rates and response rate. The other two methods which are natural extensions of the Nelson-Aalen estimator and the Kaplan-Meier estimator have similar performance. These two methods yield survival estimates which have less bias and more precise than the marginal mean model even in cases of small sample sizes. The weighted versions of the Nelson-Aalen and the Kaplan-Meier estimators are less affected by high censoring rates and low response rates. The bias of the method based on the marginal mean model increases rapidly with increase in censoring rate compared to the other two methods. We apply the three methods to a leukemia clinical trial dataset and also compare the results.

• Journal of the Korea Convergence Society
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• v.8 no.4
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• pp.111-122
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• 2017

The purpose of this study was to develop a computer-based cognitive bias modification program (CBM-I) and to test the efficacy of CBM-I for college students with social anxiety. Forty socially anxious individuals were randomly assigned to the CBM-I(n=21) or a waiting list condition(n=19). Both groups were assessed at the beginning and the end of the program with interpretation bias and social anxiety symptoms(e.g. B=FNE=Brief-Fear of Negative Evaluation Scale, LSAS=Liebowitz Social Anxiety Scale). The CBM-I modified interpretation by providing positive feedback when participants made benign interpretations and negative feedback in response to threat interpretations. Participants in CBM-I completed three computer sessions over three weeks. The CBM-I successfully decreased social anxiety symptoms compared to the control condition(t=2.35, p<.05; t=4.70, p<.001). This result suggests that interpretation modification may have clinical utility when applied as a multi-session intervention.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.4
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• pp.11-17
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• 2015

While most switching devices are based on PN junctions, a single layer can realize a switching device in the case of vanadium dioxide($VO_2$) thin films. In this paper, bidirectional current triggering(switching) is demonstrated in a two-terminal planar device based on a $VO_2$ thin film by illuminating the film with an infrared laser at 1550nm. To begin with, a two-terminal planar device, which had a $30{\mu}m$-wide $VO_2$ conducting layer and an electrode separation of $10{\mu}m$, was fabricated. A specific bias voltage range for stable bidirectional laser triggering was experimentally obtained by measuring the current-voltage characteristics of the fabricated device in a current-controlled mode. Then, by constructing a test circuit composed of the device, a standard resistor, and a DC voltage source, connected in series, the transient response of laser-triggered current and its response time were investigated with a DC bias voltage, included in the above specific bias voltage range, applied to the device. In the test circuit with a DC voltage source of 3.35V and a $10{\Omega}$ resistor, bidirectional laser triggering could be realized with a maximum on-state current of 15mA and a switching contrast of ~78.95.