• Smart Structures and Systems
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• 제5권4호
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• pp.369-379
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• 2009

The sudden collapse of Interstate 35 Bridge in Minneapolis gave a wake-up call to US municipalities to re-evaluate aging bridges. In this situation, structural health monitoring (SHM) technology can provide the essential help needed for monitoring and maintaining the nation's infrastructure. Monitoring long span bridges such as cable-stayed bridges effectively requires the use of a large number of sensors. In this article, we introduce a probabilistic approach to identify optimal locations of sensors to enhance damage detection. Probability distribution functions are established using an artificial neural network trained using a priori knowledge of damage locations. The optimal number of sensors is identified using multi-objective optimization that simultaneously considers information entropy and sensor cost-objective functions. Luling Bridge, a cable-stayed bridge over the Mississippi River, is selected as a case study to demonstrate the efficiency of the proposed approach.

• 제어로봇시스템학회논문지
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• 제16권1호
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• pp.33-39
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• 2010

The interaction of emotion is an important factor in Human-Robot Interaction(HRI). This requires a contextual appraisal of emotion extracting the emotional information according to the events happened from past to present. In this paper an emotion appraisal system based on the cognitive context is presented. Firstly, a conventional emotion appraisal model is simplified to model a contextual emotion appraisal which defines the types of emotion appraisal, the target of the emotion induced from analyzing emotional verbs, and the transition of emotions in the context. We employ a language based cognitive system and its sentential memory and object descriptor to define the type and target of emotion and to evaluate the emotion varying with the process of time with the a priori emotional evaluation of targets. In a experimentation, we simulate the proposed emotion appraisal system with a scenario and show the feasibility of the system to HRI.

• 한국음향학회지
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• 제21권4호
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• pp.146-146
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• 2002

We present a new technique for achieving source separation when given only a single channel recording. The main idea is based on exploiting the inherent time structure of sound sources by learning a priori sets of time-domain basis functions that encode the sources in a statistically efficient manner. We derive a learning algorithm using a maximum likelihood approach given the observed single channel data and sets of basis functions. For each time point we infer the source parameters and their contribution factors. This inference is possible due to the prior knowledge of the basis functions and the associated coefficient densities. A flexible model for density estimation allows accurate modeling of the observation, and our experimental results exhibit a high level of separation performance for simulated mixtures as well as real environment recordings employing mixtures of two different sources. We show separation results of two music signals as well as the separation of two voice signals.

• 대한전기학회논문지
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• 제37권9호
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• pp.646-654
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• 1988

In this paper, a speed controller using a microcomputer is implemented and applied to a DC Servo Motor. Adaptive control is applied to a system for which a priori knowledge to its mathematical model is insufficient, on the basis of input and output data an apropriate controller is constructed through which the system input is synthesized. The pole-placement PID self tuning control algorithms as a control algorithm is used to compare the performance of the controller with that of the classical PID controller through computer simulations and experiments.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1402-1407
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• 2004

Moving a fragile object from an initial point to a goal location in minimum time without damage is pursued in this paper. In order to achieve the goal, first of all, the range of maximum acceleration and velocity are specified, which the manipulator can generate dynamically on the path that is planned a priori considering the geometrical constraints. Later, considering the impulsive force constraint of the object, the range of maximum acceleration and velocity are going to be obtained to keep the object safe while the manipulator is carrying it along the curved path. Finally, a time-optimal trajectory is planned within the maximum allowable range of the acceleration and velocity. This time optimal trajectory planning can be applied for real applications and is suitable for not only a continuous path but also a discrete path.

• 전자공학회논문지B
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• 제33B권4호
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• pp.11-16
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• 1996

This paper proposes a deadzone estimator for robust system identification. In order to cope with the drift phenomena occurred in where system inputs are not sufficiently excited in adaptive control, we introduce a novel and flexible bound condition against a fixed constant. It is derived from a forgetting factor and a rational value of the traces of the covariance matrices between step k and k-1. The key feature of this is that it does not require a priori for the bound. Also, the calculation of it is more simple than the one of literatures. The simulation results are examined for showing the practical performance of this algorithm.

• 대한한의학원전학회지
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• 제26권4호
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• pp.155-179
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• 2013

Is the history of surgery an independent field of research into Chinese medicine? The historical sources are fragmentary, scattered, and riddled with fantastical descriptions. To unlock the references made in sixteenth-century texts to the use of silk thread to stitch up damaged tracheas, which are taken to be factual, the author of this article proposes a research method he calls "investigating precedents." Every independent reference to this kind of surgery must be dealt with separately. We cannot assume, a priori, that a reference to what must have been a very sophisticated procedure is either a far-fetched interpretation or a fabrication, nor should we evaluate it according to modern surgical criteria. Apart from extraordinary cases, we have no records of other types of surgery in the history of Chinese medicine, therefore we must find a method that allows us to investigate these records on their own terms.

• International Journal of Control, Automation, and Systems
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• 제1권2호
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• pp.163-170
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• 2003

The optimal Bayesian filter for a single target is known to provide the best tracking performance in a cluttered environment. However, its main drawback is the increase in memory size and computation quantity over time. In this paper, the inevitable predicament of the optimal Bayesian filter is resolved in a suboptimal fashion through the use of a receding horizon strategy. As a result, the problems of memory and computational requirements are diminished. As a priori information, the horizon initial state is estimated from the validated measurements on the receding horizon. Consequently, the suboptimal algorithm proposed allows for real time implementation.

• 제어로봇시스템학회논문지
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• 제20권9호
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• pp.895-899
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• 2014

This paper presents the balancing control of a unicycle robot using air power. Since the robot has one wheel to move forward and backward, the balancing control is quite challenging. To control the balancing angle, the accurate angle estimation by a tilt and a gyro sensor is required a priori. A complementary filter is implemented to eliminate the defects of two sensors and to fuse together to estimate an accurate balancing angle. The optimal design of air ducts is found empirically. Experimental studies of the balancing control of a unicycle robot confirm that the robot is well regulated without falling down.

• Journal of Mechanical Science and Technology
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• 제15권2호
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• pp.217-224
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• 2001

In this paper, the relocation of a mobile robot is considered such that it enables the robot to determine its position with respect to a global reference frame without any $\alpha$ priori position information. The robot acquires sonar range data from a two-dimensional model composed of planes, corners, edges, and cylinders. Considering individual range as data features, the robot searches the best position where the data features of a position matches the environmental model using a constraint-based search method. To increase the search efficiency, a hypothesize and-verify technique is employed in which the position of the robot is calculated from all possible combinations of two range returns that satisfy the sonar sensing model. Accurate relocation is demonstrated with the results from sets of experiments using sparse sonar data in the presence of unmodeled objects.