• 한국정밀공학회지
• /
• 제27권6호
• /
• pp.82-89
• /
• 2010

Ankle-foot orthosis with an artificial pneumatic muscle which is intended for the assistance of plantarfelxion torque was developed. In this study, power pattern of the device in the various pneumatics and the effectiveness of the system were investigated. The pneumatic power was provided by ankle-foot orthosis controlled by user‘s physiological signal, that is, muscular stiffness in soleus muscle. This pneumatic power can assist plantarflexion torque of ankle joint. The subjects performed maximal voluntary isokinetic plantarflexion motion on a biodexdynamometer in different pneumatics, and they completed three conditions: 1) without wearing the orthosis, 2) wearing the orthosis with artificial muscles turned off, 3) wearing the orthosis activated under muscular stiffness control. Through these experiments, we confirmed the effectiveness of the orthosis and muscular stiffness control using the analyzing isokinetic plantarflexion torque. The experimental results showed that isokinetic torques of plantarflexion motion of the ankle joints gradually increased in incremental pneumatic. The effectiveness of the orthosis was -7.26% and the effectiveness of the muscular stiffness control was 17.83% in normalized isokinetic plantarflexion torque. Subjects generated the less isokinetic torques of the ankle joints in wearing the orthosis with artificial muscles turned off, but isokinetic torques were appropriately reinforced in condition of wearing the orthosis activated under muscular stiffness control(17.83%) compared to wearing the orthosis(-7.26%). Therefore, we respect that developed powered orthosis is applied in the elderly that has weak muscular power as the rehabilitation equipment.

• 한국동물생명공학회지
• /
• 제36권2호
• /
• pp.82-90
• /
• 2021

In the present study, we examined if deep uterine artificial insemination (DUAI) can improve the pregnancy rate of artificial insemination (AI) using epididymal spermatozoa (ES) in Hanwoo cattle. The estrus cycles of 88 Hanwoo cows were synchronized, and 17 cows were artificially inseminated using the DUAI method with ES, 20 cows were artificially inseminated via the uterine body (BUAI) method with ES, and as a control, 51 cows were inseminated by using the BUAI method with ejaculated spermatozoa from 1 proven bull after frozen thawing. The pregnancy rate of the DUAI method (58.8%) was higher than that of the BUAI method (25.0%, p = 0.0498). The motility of ES was examined immediately after thawing and after 3 and 6 h of incubation. The rapid progressive sperm motility of the control group was significantly higher than that of the ES group immediately after thawing and after 3 and 6 h of incubation (p < 0.05). The straight line velocity and average path velocity of the ES group after 6 h of incubation were significantly lower than those in the control group (p < 0.05). The linearity and amplitude of lateral head of ES were lower than those at 6 h (p < 0.05). The flagellar beat cross frequency and hyperactivation of ES were lower than the control spermatozoa immediately after thawing and at 3 h (p < 0.05). These motility parameters suggested that ES had a low motility and fertilization ability compared to the control spermatozoa. After frozen-thawing and 3 h of incubation, the percentage of live spermatozoa with intact acrosomes in the ES was significantly lower than that in ejaculated spermatozoa (p < 0.05). Our findings suggested that the DUAI method can overcome the low pregnancy rate of ES, despite the low motility, viability, and fertilization ability of ES.

• Journal of Platform Technology
• /
• 제11권1호
• /
• pp.38-51
• /
• 2023

인공지능에 기반한 손 제스처 인식 정보를 활용한 지능형 인터페이스 알고리즘을 제안한다. 이 방법은 기능적으로 사용자 손 제스처의 추적 및 인식을 미디어파이프와 KNN, LSTM, CNN의 인공지능 기법을 사용해 다양한 동작을 빠르고 지능적으로 인식되는 인터페이스이다. 제안한 알고리즘 성능 평가를 위해 자체 제작한 2D 탑뷰 레이싱 게임과 로봇제어에 적용한다. 알고리즘 적용 결과 게임의 가상 객체의 다양한 움직임을 세밀하고 강건하게 제어할 수 있었으며, 실세계의 로봇 제어에 적용한 결과 이동과 정지, 좌회전, 우회전 등의 제어가 가능하였다. 또한 게임의 메인 캐릭터와 실세계 로봇을 동시에 제어하여 가상과 현실의 공존공간 상황 제어를 위한 지능형 인터페이스로 최적화된 동작도 구현하였다. 제안한 알고리즘은 신체를 활용한 자연스럽고 직관적 특성과 손가락의 미세한 움직임 인식에 따른 정교한 제어가 가능하며, 빠른 기간 내에 숙련되는 장점이 있어 지능형 사용자 인터페이스 개발을 위한 기본자료로 활용될 수 있다.

• 제어로봇시스템학회논문지
• /
• 제5권3호
• /
• pp.281-287
• /
• 1999

In this paper, a design method based on evolutionary programming for feedforward neural networks which have a single hidden layer is presented. By using an evolutionary programming, the network parameters such as the network structure, weight, slope of sigmoid functions and bias of nodes can be acquired simultaneously. To check the effectiveness of the suggested method, two numerical examples are examined. The performance of the identified network is demonstrated.

• 한국항공우주학회지
• /
• 제49권9호
• /
• pp.729-738
• /
• 2021

본 연구에서는 실속 받음각 근처에 발생하는 익형 위의 유동박리를 억제하기 위하여 인공신경망 기반의 피드백 유동제어를 NACA0015 익형에 수치적으로 적용하였다. 익형 위 박리영역 크기의 축소화라는 제어 목표를 달성하기 위해 익형의 박리 지점 근처에 인위적 외란(Blowing & Suction) 제어 신호를 적용하였다. 유동의 운동을 나타내는 시스템 모델링 단계에서 압력데이터에 적합직교분해(Proper Orthogonal Decomposition)를 적용하여 유동제어에 필요한 운동 모드를 추출하고 유동의 특성을 분석하였다. 분해된 모드를 기반으로 NARX(Nonlinear AutoRegressive Exogenous) 구조의 인공 신경망을 학습하여 유동의 운동을 나타내도록 하였으며, 최종적으로 피드백 제어루프에 작동시켰다. 예측된 제어신호를 CFD 해석에 적용하였으며 제어 유/무에 따른 공력특성을 분석하고 익형 주변의 고유 공간모드의 변화를 비교하여 제어 효과를 분석하였다. 본 연구에서 진행된 피드백 제어는 약 29%의 압력항력 감소효과를 보여주었으며, 이는 익형 뒷전의 큰 압력회복으로 인해 나타나는 것을 확인하였다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.353-354
• /
• 2014

An active vibration control technique of a time-varying cantilever beam is proposed in this study. A simple in-house coil sensor instead of expensive commercial sensors was used to measure the vibrational displacement of the beam. Active band pass filters and artificial neutral net works detect the frequencies, amplitudes, and phases of the main vibration mode. The time constants of the low pass filter representing the positive position feedback controller are updated in real-time, which generates the control voltage input to actuate the piezoelectric actuator and suppress the vibration. An experiment was successfully performed to verify the algorithm for a cantilever beam, which fundamental natural frequency arbitrarily varies between 9 Hz ~ 18 Hz. The present active vibration suppression technique can be applied to variety of structures which undergoes large variation of dynamic characteristics while operating.

• Smart Structures and Systems
• /
• 제15권1호
• /
• pp.227-244
• /
• 2015

This study develops a two stage procedure to identify the structural damage based on the optimized artificial neural networks. Initially, the modal strain energy index (MSEI) is established to extract the damaged elements and to reduce the computational time. Then the genetic algorithm (GA) and artificial neural networks (ANNs) are combined to detect the damage severity. The input of the network is modal strain energy index and the output is the flexural stiffness of the beam elements. The principal component analysis (PCA) is utilized to reduce the input variants of the neural network. By using the genetic algorithm to optimize the parameters, the ANNs can significantly improve the accuracy and convergence of the damage identification. The influence of noise on damage identification results is also studied. The simulation and experiment on beam structures shows that the adaptive parameter selection neural network can identify the damage location and severity of beam structures with high accuracy.

• 대한건축학회논문집:구조계
• /
• 제35권2호
• /
• pp.45-52
• /
• 2019

BEMS(Building Energy Management Systems) have been applied to office buildings and collect relevant building energy data, e.g. temperatures, mass flow rates and energy consumptions of building mechanical systems and indoor spaces. The aforementioned measured data can be beneficially utilized for developing data-driven machine learning models which can be then used as part of MPC(Model Predictive Control) and/or optimal control strategies. In this study, the authors developed ANN(Artificial Neural Network) models of an AHU (Air Handling Unit) and a chiller for a real-life office building using BEMS data. Based on the ANN models, the authors developed optimal control strategies, e.g. daily operation schedule with regard to optimal start and stop of the AHU and the chiller (500 RT). It was found that due to the optimal start and stop of the AHU and the chiller, 4.5% and 16.4% of operation hours of the AHU and the chiller could be saved, compared to an existing operation.

• 문화기술의 융합
• /
• 제10권2호
• /
• pp.447-452
• /
• 2024

생성형 인공지능 기술의 놀라운 성과가 점차 가시화됨에 따라, 기계의 인간 지배 가능성 등 잠재적인 실존 위협이 제기되는 현시점에서 인공지능에 대한 '통제 가능성'이 첨예한 글로벌 키워드로 주목받고 있다. 이에 따라 이 연구는 인공지능 기술을 중심으로 펼쳐질 미래 사회의 혁신적 변화에 대응하기 위하여 인공지능에 대한 통제 개념과 현주소, 글로벌 현황을 면밀하게 탐색함으로써 사회적 공론장 형성의 토대를 마련하고자 하는 데 목적이 있다. 이를 통해 인공지능 기술 진화에 따라 야기될 사회문제와 예측 불가능한 변수에 대해 대응책을 마련하기 위한 시사점을 모색하고, 정부 규제 수립에 대한 가이드라인과 전략적 통찰력을 제시하는 한편, 사회적 공개 담론 형성을 위한 함의를 찾아 보고자 한다.

• Journal of Power Electronics
• /
• 제12권3호
• /
• pp.468-476
• /
• 2012

The interior permanent magnet synchronous motor (IPMSM) has been widely used in electric vehicle applications due to its excellent power to weigh ratio. This paper proposes the maximum torque control of an IPMSM drive using an adaptive learning (AL) fuzzy neural network (FNN) and an artificial neural network (ANN). This control method is applicable over the entire speed range while taking into consideration the limits of the inverter's rated current and voltage. This maximum torque control is an executed control through an optimal d-axis current that is calculated according to the operating conditions. This paper proposes a novel technique for the high performance speed control of an IPMSM using AL-FNN and ANN. The AL-FNN is a control algorithm that is a combination of adaptive control and a FNN. This control algorithm has a powerful numerical processing capability and a high adaptability. In addition, this paper proposes the speed control of an IPMSM using an AL-FNN, the estimation of speed using an ANN and a maximum torque control using the optimal d-axis current according to the operating conditions. The proposed control algorithm is applied to an IPMSM drive system. This paper demonstrates the validity of the proposed algorithms through result analysis based on experiments under various operating conditions.