• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.1
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• pp.41-48
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• 2014

This paper analyzes the Monte Carlo localization (MCL) method, which estimates the pose of an indoor mobile robot. A mobile robot must know where it is to navigate in an indoor environment. The MCL technique is one of the most influential and popular techniques for estimation of robot position and orientation using a particle filter. For the analysis, we perform experiments in an indoor environment with a differential drive robot and ultrasonic range sensor system. The analysis uses MATLAB for implementation of the MCL and investigates the effects of the control parameters on the MCL performance. The control parameters are the uncertainty of the motion model of the mobile robot and the noise level of the measurement model of the range sensor.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.127-133
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• 2001

The flexibility of long reach manipulators presents a difficult control problem when accurate end-point position is required. Input shaping by convolving system commands with impulse sequences has been shown to be an effective method of reducing residual vibrations in flexible systems. However, existing shapers has been considered robustness for only frequency uncertainty. However, this paper presents new multi-hump convolution(CV) input shaper that could accommodate with the simultaneous variation of natural frequency and damping ratio. Comparisons with previously proposed input shapers are presented to illustrate the qualities of the new input shaper. These new shapers will be shown to have better robustness for the variation of frequency and damping ratio.

• Journal of the Semiconductor & Display Technology
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• v.10 no.1
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• pp.83-89
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• 2011

In the case of the tracking system with an active camera, it is very difficult to guarantee real-time processing due to the attribute of vision system which handles large amounts of data at once and has time delay to process. The reliability of the processed result is also badly influenced by the slow sampling time and uncertainty caused by the image processing. In this paper, we figure out dynamic characteristics of pixels reflected on the image plane and derive the mathematical model of the vision tracking system which includes the actuating part and the image processing part. Based on this model, we find a controller that stabilizes the system and enhances the tracking performance to track a target rapidly. The centroid is used as the position index of moving object and the DC motor in the actuating part is controlled to keep the identified centroid at the center point of the image plane.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.445-450
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• 1998

In this paper, a robust nonlinear prediction-type controller (RNPC) is developed for the continuous time nonlinear system whose control objective is composed of system output and its desired value. The basic control law of RNPC is derived such that the future response of the system is first predicted by appropriate functional expansions and the control law minimizing the difference between the predicted and desired responses is then calculated. RNPC which involves two controls, i.e., the auxiliary and robust controls into the basic control, shows the stable closed loop dynamics of nonlinear system of any relative degree and provides the robustness to the nonlinear system with parameter/modeling uncertainty. Simulation tests for the position control of a two-link rigid body manipulator confirm the performance improvement and the robustness of RNPC.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.11
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• pp.905-912
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• 1989

An adaptive control scheme is presented for uncertain systems whose uncertainties are upper-bounded by a linear combination of unknown constants and known continuous functions. The state of the closed-loop system is proven to be ultimately bounded. The proposed method modifies the method of Corless and Leitmann in the following two respects. First, the linear region of the saturation function in controller is fixed. Second, the intergration from in parameter estimator is replaced by a low pass filter form. These modifications prevent performance degradation and destabilization of the control system more effectively. The norm of the system states can be made sufficiently small by an appropriate choice of design parameters in the control law. The applicability of the proposed scheme is demonstrated in the position control of a simple pendulum via simulation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.08a
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• pp.119-123
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• 2000

In this paper, authors introduce about Wide Range Vessel Traffic Service (VTS) system using Automatic Identification System (AIS). In order to develop the prototype of Wide Range VIS system, Korean satellite is used for data communication system for AIS. In this system, ship position obtained by using GPS is reported automatically to VTS center through Korean satellite. By using this system, VTS center can cover more wide area than the case using radar only. And the uncertainty of information is decrease. The results of test show the good possibility of VTS using satellite and AIS.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.36.5-36
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• 2001

Localization is one of the key problems in the navigation of autonomous mobile robots. The probabilistic Markov localization approaches offer a good mathematical framework to deal with the uncertainty of environment and sensor readings but their use for realtime applications is limited by their computational complexity. This paper aims to reduce the high computational cost associated with the probabilistic Markov localization algorithm. We propose a hybrid landmark-based localization method combining triangulation and probabilistic approaches, which can efficiently update position probability grid, while the probabilistic framework allows to make use of any available sensor data to refine robot´s belief about its current location. The simulation results show the effectiveness and robustness of the method.

• Journal of Plant Biology
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• v.29 no.3
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• pp.207-231
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• 1986

To clarify the species of genus Deutzia (Saxifragaceae, s. l.) in Korea, the taxonomic description was undertaken and interspecific relationships was discussed based on the external morphology with the light and scanning electron microscopes and the distributional pattern with specimens deposited in the herbaria. The presence or absence, number of rays, position and frequency of the stellate trichome, inflorescence and the morphology and venation pattern of petal were approved as the good characters to classify the Korean Deutzias. Although 17 kinds of Deutzia were reported in Korea hitherto, 9 kinds were excluded owing to the taxonomic treatment based on the comparative external morphology and the distributional uncertainty. Thus genus Deutzia in Korea could be rearranged as 2 sections, 3 subsection, 7 species and 1 variety. Among them, 4 species were considered as the endemic species in Korea.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.5
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• pp.303-309
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• 2011

In this paper, an intelligent force control technique is applied to an autonomous helicopter. Although most research on the autonomous helicopter system is about navigation and control, force control of an autonomous helicopter system is quite new and not presented yet. After controlling the position of the helicopter by the LQR method, force control is applied. The adaptive impedance force control algorithm is introduced and tested to regulate the desired force under unknown location and stiffness of the environment. To compensate for uncertainty from outer disturbance, a neural network is added to form an intelligent force control framework. Simulation studies show that the proposed force control algorithm works well.

• Asia Marketing Journal
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• v.18 no.1
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• pp.75-97
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• 2016

Globalization and the emergence of new markets has placed increased emphasis on cross-cultural sales and marketing research. Despite considerable advances in the personal selling literature, little is known about the cross-cultural transferability of key constructs. Given the degree to which well-accepted relational sales behaviors such as ASB and customer oriented selling reflect Western values such as individualism and low uncertainty avoidance, the relative efficacy of such practices in alternative cultural context is less clear. Using a Korean sample, our results confirm the beneficial direct effects of these relational selling practices upon performance. However, we also find strong workgroup interdependence diminishes the effects of ASB and that performance fully mediates the relationship between both sales behaviors and job satisfaction. In contrast to prior results, we find female salespeople and those newer to their position demonstrate stronger ASB.