• 한국멀티미디어학회논문지
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• 제17권8호
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• pp.968-976
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• 2014

Authentication methods on smartphone are demanded to be implicit to users with minimum users' interaction. Existing authentication methods (e.g. PINs, passwords, visual patterns, etc.) are not effectively considering remembrance and privacy issues. Behavioral biometrics such as keystroke dynamics and gait biometrics can be acquired easily and implicitly by using integrated sensors on smartphone. We propose a biometric model involving keystroke dynamics for implicit authentication on smartphone. We first design a feature extraction method for keystroke dynamics. And then, we build a fusion model of keystroke dynamics and gait to improve the authentication performance of single behavioral biometric on smartphone. We operate the fusion at both feature extraction level and matching score level. Experiment using linear Support Vector Machines (SVM) classifier reveals that the best results are achieved with score fusion: a recognition rate approximately 97.86% under identification mode and an error rate approximately 1.11% under authentication mode.

• Asian Pacific Journal of Cancer Prevention
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• 제13권5호
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• pp.1851-1856
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• 2012

Immigration to a nation with a stronger anti-smoking environment has been hypothesized to make smoking less common. However, little is known about how environments influence risk of smoking across the lifecourse. Research suggested a linear decline in smoking over the lifecourse but these associations, in fact, might not be linear. This study assessed the possible nonlinear associations between age and smoking and examined how these associations differed by environment through comparing Koreans in Seoul, South Korea and Korean Americans in California, United States. Data were drawn from population based telephone surveys of Korean adults in Seoul (N=500) and California (N=2,830) from 2001-2002. Locally weighted scatterplot smoothing (lowess) was used to approximate the association between age and smoking with multivariable spline logistic regressions, including adjustment for confounds used to draw population inferences. Smoking differed across the lifecourse between Korean and Korean American men. The association between age and smoking peaked around 35 years among Korean and Korean American men. From 18 to 35 the probability of smoking was 57% higher (95%CI, 40 to 71) among Korean men versus 8% (95%CI, 3 to 19) higher among Korean American men. A similar difference in age after 35, from 40 to 57 years of age, was associated with a 2% (95%CI, 0 to 10) and 20% (95%CI, 16 to 25) lower probability of smoking among Korean and Korean American men. A nonlinear pattern was also observed among Korean American women. Social role transitions provide plausible explanations for the decline in smoking after 35. Investigators should be mindful of nonlinearities in age when attempting to understand tobacco use.

• 대한인간공학회지
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• 제32권1호
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• pp.9-16
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• 2013

Objective: The aim of this study is to investigate a trend of human error types observed in a series of verification and validation experiments for an Advanced Control Room(ACR) equipped with Lager Display Panel(LDP), Work Station Flat Panel Display(WS FPD), list type Alarm System(AS), Soft Control(SC) and Computerized Procedure System(CPS). Background: Operator behaviors in a fully computerized control room are quite different from those in a traditional hard-wired control room. Operators in an ACR all together monitor plant status and variables through their own interface system such as LDP and WS FPD, are notified of abnormal plant status through their own list type AS, control the plant through their own SC, and follow the structured procedure through their own CPS whereas operators in a traditional control room only separately do their duty directed by their supervisor. Especially the secondary task such as manipulating the user interface of ACR can be an extra burden to all the operators including the supervisor. Method: The Reason's human error classification method was applied to operators' behavioral data collected from a series of verification and validation experiments where operators showed their plant operational behaviors under a couple of harsh scenarios using the ACR simulator. Results: As operators accustomed to the new ACR system, knowledge or rule based mistakes appearing frequently in the early series of experiments decreased drastically in the latest stage of the series. Slip and lapse types of errors were observed throughout the series of experiments. Conclusion: Education and training can be one of the most important factors for the operators accustomed to the traditional control room to be adapted to the new system and to run the ACR successfully. Application: The results of this study implied that knowledge or rule based mistakes can be reduced by training and education but that lapse type errors might be reduced only through innovative improvement in human-system interface design or teamwork culture design including a new leadership style suitable for ACR.

• 마케팅과학연구
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• 제17권2호
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• pp.55-73
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• 2007

문화관광축제는 전국의 지역축제 가운데 광역시 도에서 추천한 축제 가운데 관광상품성이 크고, 경쟁력 있는 우수한 축제를 선정하여 지원하는 사업이다. 문화관광축제 종합평가계획(문화관광부, 2006)에 의하면 방문객의 만족도 평가, 전문위원 평가, 그리고 축제 개선실적 등을 감안하여 최우수축제, 우수축제, 유망축제, 예비축제로 선정되고 있다. 특히 예비축제를 제외한 문화관광축제는 공공부문의 사업비 지원을 받기 때문에 1,000여 개가 넘는 지역축제의 방문객 만족도 평가는 상호비교가 가능한 평가척도를 이용하여 종합평가분석이 이루어진고 있다. 이러한 견지에서 본 연구에서는 문화관광축제 공통평가속성이 방문객 만족과 사후행동의도에 미치는 영향관계를 파악하여, 향후 축제기획 시 방문객 만족도 제고와 지속가능한 문화관광축제로 선정되기 위한 시사점을 제시하였다. 본 연구에서는 이론연구를 통하여 문화관광축제 평가속성, 만족, 그리고 행위의도에 관한 변수를 도출하였으며, 2006 광주김치대축제 방문객을 대상으로 실증분석을 수행하였다. 문화관광축제 평가속성에 대한 요인분석을 통하여 홍보안내, 행사내용, 기념품 음식, 편의시설 요인을 도출하였으며, 축제방문객 만족과 행동의도와의 관계를 분석하였다. 연구모형을 통해 수립한 연구가설은 차이분석, 회귀분석, 공분산 구조분석 등을 통해 검증하였으며, 연구결과 모든 가설은 채택되었다. 향후 본 연구결과를 바탕으로 본 축제와 성격이 유사한 축제방문객 분석을 통한 비교연구를 기대한다.

• Journal of information and communication convergence engineering
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• 제18권2호
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• pp.132-146
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• 2020

Biometric technologies have become widely available in many different fields. However, biometric technologies using existing physical features such as fingerprints, facial features, irises, and veins must consider forgery and alterations targeting them through fraudulent physical characteristics such as fake fingerprints. Thus, a trend toward next-generation biometric technologies using behavioral biometrics of a living person, such as bio-signals and walking characteristics, has emerged. Accordingly, in this study, we developed a bio-signal authentication algorithm using electrocardiogram (ECG) signals, which are the most uniquely identifiable form of bio-signal available. When using ECG signals with our system, the personal identification and authentication accuracy are approximately 90% during a state of rest. When using fingerprints alone, the equal error rate (EER) is 0.243%; however, when fusing the scores of both the ECG signal and fingerprints, the EER decreases to 0.113% on average. In addition, as a function of detecting a presentation attack on a mobile phone, a method for rejecting a transaction when a fake fingerprint is applied was successfully implemented.

• 한국안전학회지
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• 제9권2호
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• pp.26-32
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• 1994

It is quite similar in the current automated works likewise in the past manual works that single trivial human error and/or unsafe acts may lead to serious industrial accidents. Though the traditional approach for accident prevention focused on the serious injuries or losses, that was misleaded by failure of accident perception. As Heinrich pointed out, there are still enormous numbers of unsafe acts or near-misses before a real accident happen. Thus, for industrial accident prevention, a research on unsafe acts was committed. With accident data occurred during the last decade, statistics were analyzed for extracting behavioral characteristics. After that, a practical method Integrating AHP and statistics which shows possible accident factors and their priority at an individual factory was suggested. A computer program was developed also.

• 대한인간공학회지
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• 제24권1호
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• pp.19-26
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• 2005

Mobile internet access using such devices as PDAs and cellular phones becomes popular as mobile technologies grow. However, the characteristics of small screen devices such as small screen size and pen-based input cause many usability problems. In this study, a human factors experiment was conducted to identify the factors affecting the usability of information search on a PDA. Factors manipulated in the experiment included use of wheel equipment, scroll dimension, and screen orientation. Task completion time, error frequency, and subjective satisfaction level were measured. In addition, various users' behavioral patterns such as scanning routes and mainly used scrolling methods were analyzed. Scroll dimension has a significant effect on task completion time. Scroll equipment and screen orientation affect subjective satisfaction level. The results could be applied to designing information structure of web sites for mobile use by providing vertical scroll and using external scroll equipments.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.521-522
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• 2006

This paper presents behavioral models using SIMULINK and Verilog-a for a PLL based fractional-N frequency synthesizer. The SIMULINK modeling was built in the frequency-time mixed domain whereas the Verilog-a modeling was built purely in the time domain. The simulated results of the two models were verified to show the same performance within the error tolerance. This top-down design method can provide the readiness for the transistor-level design.

• 한국전자파학회논문지
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• 제21권11호
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• pp.1220-1228
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• 2010

본 논문에서는 비선형 RF 전력 증폭기의 효율적인 다항식 기반의 이산 신호 모델링 방법을 제시하였다. 비선형 RF 증폭기의 입, 출력 신호의 샘플링 과정을 통하여 이산 비선형 모델을 추출하는 과정을 기술하고, 테일러 급수와 메모리 다항식 구조를 이용한 다항식 기반의 비선형 이산 모델에서 모델 인자인 샘플률, 비선형 차수, 최대 메모리 깊이의 변화에 따른 모델의 오차를 분석하였다. 다항식 기반의 비선형 모델에서 오차는 샘플률, 비선형 차수, 최대 메모리 깊이에 대하여 특정 값 이후부터 일반적으로 수렴하는 특성을 보인다. 이에 모델 인자값에 따른 시스템의 복잡성을 고려하는 효율적인 이산 신호 모델링 기법을 제시하였다. 모델링 효율 지수를 정의하고, 이를 활용하여 최적의 모델 인자 값을 추출하는 방법을 제시하였다. 제시한 방법을 WiBro, WCDMA 등의 다양한 신호를 가지는 RF 전력 증폭기의 모델링에 적용하고, 제시한 방법의 효율성을 검증하였다. 제안된 기법은 빠른 속도의 모델링과 저렴한 가격의 디지털부를 사용할 수 있게 하여 차후 광대역 송신기에서의 빠른 속도와 낮은 가격의 디지털 전치 왜곡기 구성 등에 활용될 수 있을 것으로 사료된다.

• 융합신호처리학회논문지
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• 제8권2호
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• pp.113-118
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• 2007

본 논문은 Pspice의 Subcircuit을 이용한 새로운 DC-DC 컨버터시스템의 피드백 제어루프 설계 방법을 제안하였다. 제안한 피드백 제어루프 설계 방식의 절차는 DC-DC 컨버터의 소신호 모델링을 기반으로 하여 Pspice의 Subcircuit으로 프로그램 하였다. 이를 위해 ABM(Analog Behavioral Modeling)을 사용하였다. ABM은 시뮬레이터에서 프로그래밍 언어로 사용 될 수 있고 수식을 전기적 회로로 나타낼 수 있으므로 방정식의 모든 변수를 전압으로 변환 할 수 있었다. Subcircuit을 사용하여 Pspice의 DC 해석으로 오차보상기의 회로 소자 값을 쉽게 얻을 수 있었다. 개발 방법을 자세히 기술하였으며 응용 예제로 제안한 DC-DC 컨버터 피드백 설계 방법의 효과를 입증하였다. PWM기법을 이용한 컨버터회로는 인덕터 전류가 연속인 연속전류모드를 적용하여 평균화 및 선형화 전류기법을 사용하여 Buck 컨버터의 제어신호를 구하였다. 극점과 영점을 선정하는 방법으로 K-계수법을 적용하였으며, 이와 같은 설계절차는 일반적으로 안정한 성능을 얻을 수 있었다.