• 자동차안전학회지
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• 제14권4호
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• pp.35-42
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• 2022

This paper presents a stochastic model predictive control (SMPC) for stop maneuver of autonomous vehicles considering perception uncertainty of stopped vehicle. The vehicle longitudinal motion should achieve both driving comfortability and safety. The comfortable stop maneuver can be performed by mimicking acceleration profile of human driving pattern. In order to implement human-like stop motion, we propose a reference safe inter-distance and velocity model for the longitudinal control system. The SMPC is used to track the reference model which contains the position uncertainty of preceding vehicle as a chance constraint. We conduct simulation studies of deceleration scenarios against stopped vehicle in urban environment. The test results show that proposed SMPC can execute comfortable stop maneuver and guarantee safety simultaneously.

• 음성과학
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• 제14권4호
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• pp.25-39
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• 2007

The present study investigated some perceptual phonetic attributes of two Korean stop types, aspirated and lax, in medial position of an accentual phrase. The intonational pattern across syllables (Jun, 1993) is argued to depend on the type of stop (aspirated vs. lax) only in the initial position of an accentual phrase. In Kang & Dilley (2007), we showed that significant differences between aspirated and lax stops in medial position of an accentual phrase exist in closure duration, voice-onset time, and fundamental frequency (F0) values for post-stop vowels. In the present perception experiment, we investigated whether these phonetic attributes contribute to the perception of these two types of stops: The closure durations and/or F0's of post-stop vowels on accentual-phrase medial words were altered and twenty native Korean speakers then judged these words as beginning with an aspirated or lax stop. Both closure duration and F0 significantly affected judgments of stop identity. These results indicate that a wider range of acoustic cues that distinguish aspirated and lax Korean stops in production also plays a role in perception. To account for these results we suggest some phonetic and phonological models of consonant-tone interactions for Korean.

• 한국도로학회논문집
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• 제16권1호
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• pp.111-118
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• 2014

PURPOSES : This study performs fundamental research on ramp-metering design criteria. METHODS : We carefully review previous studies in terms of ramp-metering design criteria and then consider applicability in Korea. For this, traffic simulation model is employed to analyze actual effect according to specific location of stop-line when implementing ramp-metering. RESULTS : When a stop-line moving forward with a 50m interval, travel speed at mainline relative to current stop-line location tends to decrease. However, traveling speed at approach roads increase about 5~18% under the same condition. When a stop-line location moving backward with a 50m interval, mainline travel speed increase approximately 17~32% whereas traveling speed at approach roads decrease. All cases are compared with the current stop-line location. CONCLUSIONS : We believe that both cases are useful with respect to freeway management. For example, moving forward a stop-line case can be used management for queuing area at ramp section and approach roads. Moving backward a stop-line case can be used for traffic control, focusing on mainline of freeways.

• The Journal of Korean Physical Therapy
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• 제23권3호
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• pp.65-70
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• 2011

Purpose: We investigated the changes in the stop-signal reaction time (SSRT) and the no-signal reaction time (NSRT) following motor sequential learning in the stop-signal task (SST). This study also determined which of the reduction0s of spatial processing time was better between blocked- and random-SST. Methods: Thirty right-handed healthy subjects without a history of neurological dysfunction were recruited. In all subjects, both the SSRT and the NSRT were measured for the SST. Tasks were classified into two categories based on the stop-signal patterns, the blocked-SST practice group and random-SST practice group. All subjects gave written informed consent. Results: In the blocked-SST group, both the SSRT and the NSRT was significantly decreased (p<0.05) but not significantly changed in the random-SST group. In the SSRT and the NSRT, the blocked-SST group was faster than the random-SST group (p<0.05). In the post-test SST after practice of each group, the SSRT was significantly decreased in the random-SST group (p<0.05), but the NSRT showed no significant changes in either group. Conclusion: These findings demonstrate that random-SST practice resulted in a decrease in internal processing times needed for a rapid stop to visual signals, indicating motor skill learning is acquired through improved response selection and inhibition.

• 대한토목학회논문집
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• 제7권4호
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• pp.115-124
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• 1987

본 연구는 피로균열이 발생한 부재의 응급적인 보수, 보강방법으로 예로부터 실제로 이용되어 온 stop-hole에 대하여 그 보수, 보강효과를 잔존수명의 관점에서 정량적인 평가를 시도한 것이다. 이를 위하여 대상 시험편에 대한 피로시험을 실시하여 그 피로거동을 검토한 결과, 피로균열에 대한 응급조치로서 stop-hole을 이용할 경우, 균열이 탄소성 거동을 하는 영역에 이르기 전에 처리하는 것이 바람직함을 알 수 있었다.

• 한국정보통신학회논문지
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• 제9권7호
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• pp.1601-1606
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• 2005

본 연구에서는 자동차가 정지하면 지정된 수초이내에 자동차의 공회전 상태를 자동적으로 정지시키고, 운전자가 출발하고자 할 때는 약속된 전기신호로 엔진의 시동을 거는 차량용 공회전 자동정지 제어시스템을 개발하였다. 이 장치는 다수의 선별된 엔진제어유닛과 변속기제어유닛의 전기신호를 입력신호로 하는 마이크로프로세서와 기타 주변 전자회로로 구성되어 있으며 자동차의 운전상태를 인식할 뿐 아니라 냉각수 온도에 따라 그 작동을 조정하고 재시동시 연료분사스킵 기법을 적용하여 자동차의 연료절약 및 유해배출가스를 저감하는 효과를 가지고 있다. 국내의 자동차 연비 및 유해배출가스측정 공인기관에서 ECE15+EUDC모드에서 본 제어시스템 장착차량의 주행시험을 실시하여 그 효과를 확인하였고 실차 적용가능성을 확보하였다.

• International Journal of Computer Science & Network Security
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• 제24권3호
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• pp.142-150
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• 2024

A conceptual model represents an understanding of a system that is going to be developed, which in this research, a driving simulation software to study driver behavior at signalised intersections. Therefore, video observation was conducted to study driver compliance behaviour within the dilemma zone at signalised intersection, with regards to driver's distance from the stop line during yellow light interval. The video was analysed using Thematic Analysis and the data extracted from it was analysed using Chi-Square Independent Test. The Thematic Analysis revealed two major themes which were traffic situation and driver compliance behaviour. Traffic situation is defined as traffic surrounding the driver, such as no car in front and behind, car in front, and car behind. Meanwhile, the Chi-Square Test result indicates that within the dilemma zone, there was a significant relationship between driver compliance behaviour and driver's distance from the stop line during yellow light interval. The closer the drivers were to the stop line, the more likely they were going to comply. In contrast, drivers showed higher non-compliant behavior when further away from stop line. This finding could help in the development of conceptual model of driving simulation with purpose in studying driver behavior.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1664-1667
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• 2005

The main function of Ball-Stop part is to operate power shift for vehicle with more than 5 ton when a driver changes gear using suitable force. This paper presents the implementation of a DFSS(Design For Six Sigma) for robust design of Ball-Stop part of power shift. The factors influencing Ball-Stop part performance is derived to find control factor. Based on this factor, contact force between head and detent pin analysis is performed to get optimal factor is analyzed and compared with contact force test result to verify reliability of design. This makes clear the reason why the proposed one is necessary and the role of DFSS.

• 대한기계학회논문집B
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• 제33권10호
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• pp.748-756
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• 2009

The effect of idling stop on $CO_2$ reduction was estimated, especially in the area of in-use vehicles. In order to know the fuel saving for each class of vehicles, a methodology to calculate the fuel saving was used along with a standard test using NIER-07 mode. Idling stop execution rate was estimated by analyzing the driving pattern of the in-use city buses, which shows about 75% at maximum. And this corresponds to about 5.4% reduction of the daily total fuel consumption. Finally, $CO_2$ reduction in the automotive sector was estimated, which concludes that, when idling stop device is used, about 480 thousand and 450 thousand tons of $CO_2$ could be reduced with in-use city buses and taxis, respectively. This amount corresponds to about 1.2% of $CO_2$ reduction in the automotive sector.

• 자동차안전학회지
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• 제12권2호
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• pp.33-39
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• 2020

This paper presents an Around View Monitoring (AVM) stop-line detection based longitudinal position correction algorithm for automated driving on urban roads. Poor positioning accuracy of low-cost GPS has many problems for precise path tracking. Therefore, this study aims to improve the longitudinal positioning accuracy of low-cost GPS. The algorithm has three main processes. The first process is a stop-line detection. In this process, the stop-line is detected using Hough Transform from the AVM camera. The second process is a map matching. In the map matching process, to find the corrected vehicle position, the detected line is matched to the stop-line of the HD map using the Iterative Closest Point (ICP) method. Third, longitudinal position of low-cost GPS is updated using a corrected vehicle position with Kalman Filter. The proposed algorithm is implemented in the Robot Operating System (ROS) environment and verified on the actual urban road driving data. Compared to low-cost GPS only, Test results show the longitudinal localization performance was improved.