• The Journal of Korea Robotics Society
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• v.3 no.3
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• pp.212-218
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• 2008

Collision avoidance is a fundamental and important task of an autonomous mobile robot for safe navigation in real environments with high uncertainty. Obstacles are classified into static and dynamic obstacles. It is difficult to avoid dynamic obstacles because the positions of dynamic obstacles are likely to change at any time. This paper proposes a scheme for vision-based avoidance of dynamic obstacles. This approach extracts object candidates that can be considered moving objects based on the labeling algorithm using depth information. Then it detects moving objects among object candidates using motion vectors. In case the motion vectors are not extracted, it can still detect the moving objects stably through their color information. A robot avoids the dynamic obstacle using the dynamic window approach (DWA) with the object path estimated from the information of the detected obstacles. The DWA is a well known technique for reactive collision avoidance. This paper also proposes an algorithm which autonomously registers the obstacle color. Therefore, a robot can navigate more safely and efficiently with the proposed scheme.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.12
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• pp.679-688
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• 2003

In order to navigate the mobile robots safely in unknown environments, many researches have been studied to devise navigational algorithms for the mobile robots. In this paper, we propose a navigational algorithm that consists of an obstacle-avoidance behavior module, a goal-approach behavior module and a radial basis function network(RBFN) supervisor. In the obstacle-avoidance behavior module and goal-approach behavior module, the fuzzy-artificial immune networks are used to select a proper steering angle which makes the autonomous mobile robot(AMR) avoid obstacles and approach the given goal. The RBFN supervisor is employed to combine the obstacle-avoidance behavior and goal-approach behavior for reliable and smooth motion. The outputs of the RBFN are proper combinational weights for the behavior modules and velocity to steer the AMR appropriately. Some simulations and experiments have been conducted to confirm the validity of the proposed navigational algorithm.

• Asia-Pacific Journal of Business
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• v.13 no.1
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• pp.231-245
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• 2022

Purpose - The purpose of this study is to examine the effect of book-tax conformity on conforming tax avoidance and non-conforming tax avoidance. Design/methodology/approach - This study uses financial data from 1996 to 2019 of 34 countries. We regress conforming or non-conforming tax avoidance on book-tax conformity. We use the book-tax conformity measure developed by Atwood et al. (2010), the non-conforming tax avoidance measure developed by Desai and Dharmapala (2006), and the conforming tax avoidance measure developed by Badertscher et al. (2019). Findings - First, book-tax conformity has a significant positive relationship with non-conforming tax avoidance. Second, book-tax conformity is not statistically related to conforming tax avoidance. Research implications or Originality - While prior research focuses on the effect of book-tax conformity on earnings quality, we examine on the effect on tax avoidance. Furthermore, this study is expected to provide important policy implications regarding the types of tax avoidance strategies that tax authorities should pay attention to. Our results imply that tax authorities in countries with high book-tax conformity should pay more attention to non-conforming tax avoidance than to conforming tax avoidance.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.11
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• pp.1038-1043
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• 2010

In this paper, an adaptive sliding-mode formation control and collision avoidance are proposed for electrically driven nonholonomic mobile robots with model uncertainties and external disturbances. A sliding surface based on the leader-follower approach is developed to achieve the desired formation in the presence of model uncertainties and disturbances. Moreover, by using the collision avoidance function, the mobile robots can avoid the obstacles successfully. Finally, simulations illustrate the effectiveness of the proposed control system.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10a
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• pp.921-925
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• 1987

This paper presents the recent findings for collision avoidance of two manipulators in addition to the results shown in Lee [4]. The collision situation we assume here is that the prespecified final time $K_{f}$ and the prespecified path of one robot can be modified for the purpose of collision avoidance with the other robot. The collision avoidance problem is resolved into three independent categories for a systematic approach.h.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.11
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• pp.970-975
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• 2002

We suggests an effective method to construct time-varying C-obstacles in the 3-dimensional configuration space (C-space) using free arc. The concept of free arc was defined mathematically and the procedure to find free arc in the case off-dimensional C-space was derived in [1]. We showed that time-varying C-obstacles can be constructed efficiently using this concept, and presented simulation results for two SCARA robot manipulators to verify the efficacy of the proposed approach. In this paper, extensions of this approach to the 3-dimensional C-space is introduced since nearly all industrial manipulators are reasonably treated ill the too or three dimensional C-space f3r collision avoidance problem The free arc concept is summarized briefly and the method to find lice arc in the 3-dimensional f-space is explained. To show that this approach enables us to solve a practical collision avoidance problem simulation results f3r two PUMA robot manipulators are presented.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.8
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• pp.893-898
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• 1988

This paper presents the recent findings for collision avoidance of two manipulators in terms of motion level modifications. The collision situation we assume here is that the prespecified final time Kf and the prespecified path of one robot can be modified for the purpose of collision avoidance with the other robot. The collision avoidance problem is resolved into three independent categories for a systematic approach.

• Korean Journal of Child Studies
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• v.26 no.5
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• pp.263-279
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• 2005

This study explored the participant roles and the cross-sectional and longitudinal relationships between interpersonal behavior characteristics and bullying/victimization. The subjects were 4th and 5th grade children and instruments were the Participant Roles Scale, Self-Report Coping Scale, Teenage Inventory of Social Skills, and Social Anxiety/Avoidance. They were contacted again one year later. In the distribution of participant roles at Time 1, defender of the victim was highest, then outsider; at Time 2 outsider was the highest and then defender. There was a tendency of gender difference in distribution of participant roles only at Time 1. Males were more in the group of reinforcer; females were more in the group of defender and victim. There were high positive correlations among bully/reinforcer/assistant scores. In the concurrent view, children who used approach coping strategies and showed higher social skills were more likely to be defender. Children who had lower social skills and higher social anxiety and social avoidance were more likely to be victim. In the longitudinal view, children who had developed higher social skills were more likely to be defender. Children who had employed less approach coping strategies and had showed lower social skills and higher social avoidance were more likely to be victim.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.6
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• pp.470-476
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• 2001

This paper presents a new algorithm of path planning and obstacle avoidance for autonomous mobile robots with vision system that is working in unknown environments. Distance variation technique is used in path planning to approach the target and avoid obstacles in work space as well . In this approach, the Sobel operator is employed to detect edges of obstacles and the distances between the mobile robot and the obstacles are measured. Fuzzy rules are used for trajectory planning and obstacle avoidance to improve the autonomy of mobile robots. It is shown by computer simulation that the proposed algorithm is superior to the vector field approach which sometimes traps the mobile robot into some local obstacles. An autonomous mobile robot with single vision is developed for experiments. We also show that the developed mobile robot with the proposed algorithm is navigating very well in complex unknown environments.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.13 no.2
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• pp.91-99
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• 2013

An autonomous unmanned underwater vehicle is a type of marine self-propelled robot that executes some specific mission and returns to base on completion of the task. In order to successfully execute the requested operations, the vehicle must be guided by an effective navigation algorithm that enables it to avoid obstacles and follow the best path. Architectures and principles for intelligent dynamic systems are being developed, not only in the underwater arena but also in related areas where the work does not fully justify the name. The problem of increasing the capacity of systems management is highly relevant based on the development of new methods for dynamic analysis, pattern recognition, artificial intelligence, and adaptation. Among the large variety of navigation methods that presently exist, the dynamic window approach is worth noting. It was originally presented by Fox et al. and has been implemented in indoor office robots. In this paper, the dynamic window approach is applied to the marine world by developing and extending it to manipulate vehicles in 3D marine environments. This algorithm is provided to enable efficient avoidance of obstacles and attainment of targets. Experiments conducted using the algorithm in MATLAB indicate that it is an effective obstacle avoidance approach for marine vehicles.