• International Journal of Control, Automation, and Systems
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• 제6권2호
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• pp.282-287
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• 2008

In distributed mobile robot systems, autonomous robots accomplish complicated tasks through intelligent cooperation with each other. This paper presents behavior learning and online distributed evolution for cooperative behavior of a group of autonomous robots. Learning and evolution capabilities are essential for a group of autonomous robots to adapt to unstructured environments. Behavior learning finds an optimal state-action mapping of a robot for a given operating condition. In behavior learning, a Q-learning algorithm is modified to handle delayed rewards in the distributed robot systems. A group of robots implements cooperative behaviors through communication with other robots. Individual robots improve the state-action mapping through online evolution with the crossover operator based on the Q-values and their update frequencies. A cooperative material search problem demonstrated the effectiveness of the proposed behavior learning and online distributed evolution method for implementing cooperative behavior of a group of autonomous mobile robots.

• Journal of Information Processing Systems
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• 제4권4호
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• pp.159-168
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• 2008

Human-Robot Interaction (HRI), based on already well-researched Human-Computer Interaction (HCI), has been under vigorous scrutiny since recent developments in robot technology. Robots may be more successful in establishing common ground in project-based education or foreign language learning for children than in traditional media. Backed by its strong IT environment and advances in robot technology, Korea has developed the world's first available e-Learning home robot. This has demonstrated the potential for robots to be used as a new educational media - robot-learning, referred to as 'r-Learning'. Robot technology is expected to become more interactive and user-friendly than computers. Also, robots can exhibit various forms of communication such as gestures, motions and facial expressions. This study compared the effects of non-computer based (NCB) media (using a book with audiotape) and Web-Based Instruction (WBI), with the effects of Home Robot-Assisted Learning (HRL) for children. The robot gestured and spoke in English, and children could touch its monitor if it did not recognize their voice command. Compared to other learning programs, the HRL was superior in promoting and improving children's concentration, interest, and academic achievement. In addition, the children felt that a home robot was friendlier than other types of instructional media. The HRL group had longer concentration spans than the other groups, and the p-value demonstrated a significant difference in concentration among the groups. In regard to the children's interest in learning, the HRL group showed the highest level of interest, the NCB group and the WBI group came next in order. Also, academic achievement was the highest in the HRL group, followed by the WBI group and the NCB group respectively. However, a significant difference was also found in the children's academic achievement among the groups. These results suggest that home robots are more effective as regards children's learning concentration, learning interest and academic achievement than other types of instructional media (such as: books with audiotape and WBI) for English as a foreign language.

• 대한정형도수물리치료학회지
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• 제28권1호
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• pp.71-80
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• 2022

Background: This study investigated the effect of robot-assisted arm training on muscle activity of arm and weight bearing in stroke patients. Methods: The study subjects were selected 20 stroke patients who met the selection criteria. 10 people in the robot-assisted arm training group and 10 people in the task-oriented arm training group were randomly assigned. The experimental group performed robot-assisted arm training, and the control group performed task-oriented arm training for 6 weeks, 5 days a week, 30 minutes a day. The measurement tools included surface electromyography and smart insole system. Data were analyzed using independent sample t-test and the paired sample t-test. Results: Comparing the muscle activity of arm within the group, the experimental group and the control group showed significant differences in muscle activity in the biceps brachii, triceps brachii, anterior deltoid, upper trapezius, middle trapezius, and lower trapezius. Comparing the muscle activity of arms between the groups, the experimental group showed significant difference in all muscle activity of arm compared to the control group. Comparing the weight bearing within the groups, the experimental group showed significant difference in the affected side and non-affected side weight bearings and there were significant differences in anterior and posterior weight bearing. The control group showed significant difference only in the non-affected side weight bearing. Comparing the weight bearings between groups, the experimental group showed significant difference in the affected side and non-affected side weight bearings compared to the control group. Conclusion: This study confirmed that robot-assisted arm training applied to stroke patients for 6 weeks significantly improved muscle activity of arm and weight bearing. Based on these results, it is considered that robot-assisted arm training can be a useful treatment in clinical practice to improve the kinematic variables in chronic stroke patients.

• 로봇학회논문지
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• 제15권4호
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• pp.330-340
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• 2020

The purpose of this study was to develop Dementia-Care-Robot integrated program based on group customization and to identify effects on IADL, depression, and attitudes toward robot. This study was nonequivalent control group pre-post test design. The subjects were 40 elders diagnosed with mild dementia participating in the dementia center daily program (20 in the experimental group and 20 in the control group). Each session lasted for 30 minutes, twice a week during 6 weeks. Data were collected from July 16 to November 7, 2019, and were analyzed using SPSS WIN 22.0 program to identify differences between groups for variables. After the program, the experimental group improved in IADL, depression, but there were no significant differences between the two groups. In attitude toward robot, the experimental group showed positive change to the robot, but the control group showed negative change to it, also there was a significant difference between the two groups. Findings indicate that integrated program using Dementia-Care-Robot has potential as a strategy to improve the symptoms of dementia and to delay the progression. It needs to be applied in the medical field through convergent approach of engineering.

• 한국컴퓨터정보학회논문지
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• 제20권8호
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• pp.121-128
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• 2015

This study aimed to investigate the effects of an unplugged robot education system capable of computerless coding education. Specifically, this study compared this education system with PicoCricket, an educational robot that can also be used with elementary students in lower grades, using assessment tools on perceived usefulness and ease. Using random sampling and randomized assignment for more objective validation, 30 participants were assigned to the unplugged robot education system group (experimental group) and 30 participants were assigned to the PicoCricket group (control group), for a total of 60 study participants. The research procedure included verification of the equivalence of the two groups by conducting a pretest after a 2-hour basic training session on algorithms and programming. The experimental and control groups learned the same content using different educational tools in accordance with software training guidelines for a total of 12 hours. Then, the difference in perceived usefulness and ease between the two groups was examined using a post-treatment test. The study results showed that scores on both dependent variables, perceived usefulness and perceived ease, were significantly higher in the experimental group than the control group. Moreover, scores on all sub-variables of the dependent variables were significantly higher in the experimental group than the control group. These results suggest that learners using the unplugged robot education system found it more useful and easier to use than learners using the existing educational robot, PicoCricket. This study's findings are significant, as according to the technology acceptance model, the perceived usefulness and ease of an educational tool are important variables that determine the acceptance of the tool (i.e., persistence of learning).

• Journal of Communications and Networks
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• 제9권3호
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• pp.296-311
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• 2007

Mobile multi-robot teams are useful in many critical applications such as search and rescue. Explicit communication among robots in such mobile multi-robot teams is useful for the coordination of such teams as well as exchanging data. Since many applications for mobile robots involve scenarios in which communication infrastructure may be damaged or unavailable, mobile robot teams frequently need to communicate with each other via ad hoc networking. In such scenarios, low-overhead and energy-efficient routing protocols for delivering messages among robots are a key requirement. Two important primitives for communication are essential for enabling a wide variety of mobile robot applications. First, unicast communication (between two robots) needs to be provided to enable coordination and data exchange. Second, in many applications, group communication is required for flexible control, organization, and management of the mobile robots. Multicast provides a bandwidth-efficient communication method between a source and a group of robots. In this paper, we first propose and evaluate two unicast routing protocols tailored for use in ad hoc networks formed by mobile multi-robot teams: Mobile robot distance vector (MRDV) and mobile robot source routing (MRSR). Both protocols exploit the unique mobility characteristics of mobile robot networks to perform efficient routing. Our simulation study show that both MRDV and MRSR incur lower overhead while operating in mobile robot networks when compared to traditional mobile ad hoc network routing protocols such as DSR and AODV. We then propose and evaluate an efficient multicast protocol mobile robot mesh multicast (MRMM) for deployment in mobile robot networks. MRMM exploits the fact that mobile robots know what velocity they are instructed to move at and for what distance in building a long lifetime sparse mesh for group communication that is more efficient. Our results show that MRMM provides an efficient group communication mechanism that can potentially be used in many mobile robot application scenarios.

• International Journal of Control, Automation, and Systems
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• 제5권6호
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• pp.681-690
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• 2007

This article presents the kinematic analysis and implementation of an interface and control of two robots-an exoskeleton master robot and a human-like slave robot with two arms. Two robots are designed and built to be used for motion-following tasks. The operator wears the exoskeleton master robot to generate motions, and the slave robot is required to follow after the motion of the master robot. To synchronize the motions of two robots, kinematic analysis is performed to correct the kinematic mismatch between two robots. Hardware implementation of interface and control is done to test motion-following tasks. Experiments are performed to confirm the feasibility of the motion-following tasks by two robots.

• Journal of Electrical Engineering and Technology
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• 제11권5호
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• pp.1433-1440
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• 2016

• International Journal of Control, Automation, and Systems
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• 제6권5호
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• pp.722-730
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• 2008

This paper proposes two novel algorithms enabling mobile robots to cooperate with each other in a reliability-based system and a time-critical system. In the reliability-based cooperative system, the concepts of a mobile ad hoc network (MANET) and an object entropy are adopted in order to coordinate a specific task. A logical robot group is created based on the exchange of request and reply messages in a robot communication group whose organization depends on transmission range. In the time-critical cooperative system, relational entropy is used to define the relationship between mobile robots. A group leader is selected based on optimizing power consumption. The proposed algorithm has been verified based on the computer-based simulation and soccer robot experiment. The performance metrics are defined. The metrics include the number of messages needed to make a logical robot group and to obtain the relationship of robots and the power consumption to select a group leader. They are verified by simulation and experiment.

• 전자공학회논문지SC
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• 제47권3호
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• pp.5-12
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• 2010

천장의 반복 무늬를 이용하여 로봇의 방향과 위치를 계산하는 새로운 알고리즘을 제안하였다. 방향 계산을 위해서 천장 영상으로부터 검출한 직선과 로봇의 현재 방향 간의 상대 각도를 계산한 후, 천장무늬에 포함된 여러 기준 직선의 방향들에 상기 상대각도를 더하여 로봇의 절대방향 후보 집합을 구성한다. 로봇 방향은 이 절대방향 후보 집합 중, 이전의 로봇 방향과 가장 가까운 방향으로 결정한다. 로봇의 위치도, 영상에서의 격자점의 화소 위치를 이용하여 로봇의 격자점과 로봇 간의 상대위치를 계산 한 후, 이전 로봇 주변의 격자점들에 상기 상대위치 벡터를 더하여 절대 위치 후보 집합을 구성하며, 이들 중 이전 로봇의 위치와 가장 가까운 위치를 현재 로봇 위치로 결정한다. 제안한 알고리즘을 이용하여 구한 위치 및 방향의 정확성을 검증하기 위한 실험을 수행하였다.