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Imitation Learning of Humanoid Locomotion Using the Direction of Landing Foot
양우성,정낙용 제어·로봇·시스템학회 2009 International Journal of Control, Automation, and Vol.7 No.4
Since it is quite difficult to create motions for humanoid robots having a fairly large number of degrees of freedom, it would be very convenient indeed if robots could observe and imitate what they want to create. To this end, this paper discusses how humanoid robots can learn through imitation taking into consideration the fact that demonstrator and imitator robots may have different kinematics and dynamics. As part of a wider interest in humanoid motion generation in general, this work mainly investigates how imitator robots adapt a reference locomotion gait copied from a demonstrator robot. Specifically, the self-adjusting adaptor is proposed, where the perceived locomotion pattern is modified to keep the direction of the lower leg contacting the ground identical between the demonstrator and the imitator, and to sustain dynamic stability by controlling the position of the center of mass. The validity of the proposed scheme is verified through simulations on OpenHRP and real experiments.
양우성,이재봉,허요원,권대현,최석관,정상덕,안두해 한국수산해양기술학회 2017 수산해양기술연구 Vol.53 No.4
This study aims to suggest the methodology to improve to estimate back-calculated fish growth parameters using weighted average. It is to contribute to correct errors in the calculation of back-calculated growth equation with unequal numbers of sample by age. If the numbers of sample were evenly collected by age, each back-calculated length at age was equal between arithmetic and weighted averages. However, most samples cannot be evenly collected by age in reality because of different catchability by fishing gear and limitation of environment condition. Therefore, the estimation of back-calculated length by weighted average method is essential to calculate growth parameters. There were some published growth equations from back-calculated length using a simple arithmetic average with different numbers of samples by age when searching for back-calculated growth equations from 91 relevant papers. In this study, the process of deriving growth equation was investigated and two different average calculations were applied to a fish growth equation, for example of Acheilognathus signifer. Growth parameters, such as ∞ , and , were estimated from two different back-calculated averages and the growth equations were compared with growth performance index. Based on the correction of back-calculated length using weighted average by age, the changes by female and male were -14.19% and -5.23% for ∞ , and 59.28% and 18.91% for , respectively. The corrected growth performance index by weighted average improved at 7.05% and 2.46% by female and male, respectively, compared to the arithmetic averages. 수산자원의 성장식 연구는 수산자원 연령구조를 파악하고 자원 상태를 평가하는데 있어 기초적이고 중요한 분야이다. 따라서 가장 적합한 방법과 모델을 선택하여 성장식을 추정하는 과정은 수산자원의 생물학적 특성을 알아내는 의미뿐만 아니라 자원량 산정 및 정도 높은 자원평가를 수행하는데 있어 오차를 줄이고 정확한 평가결과를 도출하기 위해 중요하다. 이에 본 연구에서는 가중평균을 활용하여 역계산체장 및 성장식에 오차를 줄이고 더 정확한 값을 산정함으로써, 과거 수행되어진 연구자료를 비판하기 위한 목적이 아니라, 앞으로의 정확한 수산자원평가 수행을 위해 보다 바람직하게 개선된 값을 입력자료로 제공하기 위한 방법론을 제시하고자, 산술평균이 적용되어 있는 묵납자루의 연령성장(Baek et al., 2002)의 연구결과 토대로 가중평균법을 적용하여 역계산 체장 또는 체중 성장식을 추정하였다. 산술평균이 적용된 연구에 가중평균이 적용되었을 때 성장계수 추정치는 암컷에서 L_(∞ )값은 -14.19%, K 값은 59.28%차이를 나타냈으며, 수컷에서는 L_(∞ )값은-5.23%, K 값은 18.91%로 차이를 보였다. 그리고 t_(0 )값은 암컷에서 46%, 수컷에서 36%로 차이가 확인되었다. 이를 토대로 성장률(GPI값)을 비교했을 때 암컷에서 7.05%, 수컷에서 2.46% 개선된 것을 확인할 수 있었다.
신경 진동자와 IPMC 구동기를 결합한 생체 모방형 시스템
양우성(Woosung Yang),최수호(Suho Choi),이승엽(Seung-Yop Lee) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
We propose a control scheme of the IPMC actuator exploiting neural oscillators to achieve biologically inspired motion generation and control. In general, humans or animals show novel adaptive behaviors regardless of their kinematic configurations against unexpected disturbances or environmental changes. This is because that the entrainment property of the neural oscillator plays a key role to adapt their nervous system to the natural frequency of the interacted environments. Thus we apply the biomimetic approach to a novel control of the IPMC actuator, since the IPMC has many difficulties in control such as nonlinearities, flexibility, and unexpected motion, etc. In order to demonstrate the excellence of its entrainment, we implement experimentally the proposed control approach to the IPMC actuator. The coupled IPMC actuator successfully exhibits the motion excited by the neural oscillator. Experimental results confirm biologically inspired, selfadaptive behaviors that enable the IPMC actuator to make adaptive changes corresponding to unexpected disturbances in phase.
제우성(Woo-Seong Che),이동수(Dong-Soo Lee),김정현(Jung Hyun Kim),손을호(Eul-Ho Son),양승용(Seung-Young Yang) 한국자동차공학회 2010 한국자동차공학회 지부 학술대회 논문집 Vol.2010 No.12
External gear pumps are the most widely employed source of power in hydraulic applications, allowing good performance and low manufacturing cost Generally, pumps with involute external gears are most commonly used. The undesired large pressure overshoots or spikes could be excited by virtue of the sudden volumetric change of meshing pockets. In practice, the spikes cause the gear machines to be noisy, inefficient, and have fatigue problems. In order to improve above issue, relief grooves are adopted practically. In this paper, the effects of relief groove configurations are considered by using analysis.
Smart Phone VoIP 서비스에 대한 공격과 도청 연구
천우성,박대우,양종한,Chun, Woo-Sung,Park, Dea-Woo,Yang, Jong-Han 한국정보통신학회 2011 한국정보통신학회논문지 Vol.15 No.6
VoIP 서비스는 현재 PSTN망과 인터넷망을 활용하여 기존 전화망보다 저렴한 가격에 음성통화를 할 수 있게 해주는 서비스로 확대되고 있다. 하지만 공공의 보안이 유지 되어야 할 Smart Phone VoIP의 경우 보안취약성에 대한 문제들이 발생하고, 해커의 공격을 받을 가능성이 높다. 본 논문은 유.무선 인터넷을 이용하여 Smart Phone VoIP 서비스 이용 시 발생할 수 있는 침해사고 유형을 분석하고 도청 공격을 실시하여 취약점을 분석한다. Smart Phone VoIP 취약점을 분석을 위하여 OmniPeek와 AirPcap 장비가 설치되어 있는 실험실 환경에서 도청 공격을 실시한다. 도청 공격에 따르는 Packet을 분석하고, IP을 확인하여 공격에 의한 침해사고로 도청이 이루어짐을 시험으로 증명한다. 본 논문은 Smart Phone VoIP 사용자 뿐만 아니라, 현재 행정기관에서 도입하고 있는 Smart Phone 서비스와 VoIP 서비스 보안성 강화에 기초자료로 제공 될 것이다. VoIP service by taking advantage of the current PSTN network and internet over the existing telephone network at an affordable price allows you to make voice calls to the service is being expanded. However, the security of public must be maintained for security vulnerabilities in Smart Phone VoIP case problems arise, and is likely to be attacked by hackers. In this paper, the Internet, using wired and Smart Phone VoIP services may occur during analysis of the type of incident and vulnerability analysis, the eavesdropping should conduct an attack. Smart Phone VoIP with institutional administration to analyze the vulnerability OmniPeek, AirPcap the equipment is installed in a lab environment to conduct eavesdropping attack. Packet according to the analysis and eavesdropping attacks, IP confirmed that the incident as an attack by the eavesdropping as to become the test proves. In this paper, as well as Smart Phone VoIP users, the current administration and the introduction of Smart Phone service and VoIP service as a basis for enhanced security will be provided.