• Title/Summary/Keyword: Cooperative control

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Energy-Efficient Cooperative Medium Access Control (MAC) Protocol for Wireless Sensor Networks

  • Ahmed, Mohammad Helal Uddin;Hong, Choong-Seon
    • Proceedings of the Korean Information Science Society Conference
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    • 2011.06d
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    • pp.267-268
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    • 2011
  • Recent research activities in cooperative communication focus on achieving energy efficiency and reliability. Relay selection strategy for cooperative communication improves the performance significantly. However, due to imbalance consumption of power, network might die earlier and more than 90% energy remains unused. In this paper, we provide a framework of an energy-efficient medium access control protocol that minimizes these problems and improves energy efficiency.

The Effect of Cooperative Skill Training on Elementary School Students생 Learning in Science (협동기술 훈련이 초등학생의 과학 학습에 미치는 효과)

  • 한영욱;박수경;김대홍
    • Journal of Korean Elementary Science Education
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    • v.19 no.1
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    • pp.29-39
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    • 2000
  • The purpose of this study was to investigate the effect of cooperative skill training on elementary school students' science achievement and self-esteem. Three different groups were used in this study. For the two treatment groups, cooperative loaming strategies were used and the one control group, traditional instruction was used. One of the treatment group was trained cooperative skills before the instruction. A total of 120 children sampled from 5th graders of a elementary school. All groups were taught about the change of the weather and structure of the plants. After the instruction a researcher made science achievement test and questionnaire of self-esteem were administered. The data analysis consisted of a 3(instructional strategies)×3(learning ability level) ANCOVA on the score of the achievement and self-esteem. The ANCOVA results revealed that there were significant main effect in the scores of achievement and also significant interaction effect between the instructional strategies and learning ability. The performance of high-level students in two treatment groups was higher than that of students in the control group, but the performance of high-level students with cooperative skill training was not higher than that of students without cooperative skill training. However, the performance of medium and low-level students with cooperative skill training was higher than that of students without cooperative skill training. The significant main effect was also found in the self-esteem but there were no significant interactions between the instructional strategies and learning ability. The academic self and social self of students with cooperative skill training was higher than that of students without cooperative skill training.

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CMS: Application Layer Cooperative Congestion Control for Safety Messages in Vehicular Networks

  • Lee, Kyu-haeng
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.3
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    • pp.1152-1167
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    • 2018
  • In this paper, I propose an application layer cooperative congestion control scheme for safety message broadcast in vehicular networks, called CMS, that adaptively controls a vehicle's safety message rate and transmit timing based on the channel congestion state. Motivated by the fact that all vehicles should transmit and receive an application layer safety message in a periodic manner, I directly exploit the message itself as a means of estimating the channel congestion state. In particular, vehicles can determine wider network conditions by appending their local channel estimation result onto safety message transmissions and sharing them with each other. In result CMS realizes cooperative congestion control without any modification of the existing MAC protocol. I present extensive NS-3 simulation results which show that CMS outperforms conventional congestion control schemes in terms of the packet collision rate and throughput, especially in a high-density traffic environment.

BOXES-based Cooperative Fuzzy Control for Cartpole System

  • Kwon, Sung-Gyu
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.7 no.1
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    • pp.22-29
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    • 2007
  • Two fuzzy controllers defined by 2 input variables cooperate to control a cartpole system in terms of balancing as well as centering. The cooperation is due to the BOXES scheme that selects one of the fuzzy controllers for each time step according to the content of box that is established through the critic of the control action by the fuzzy controllers. It is found that the control scheme is good at controlling the cartpole system so that the system is stabilized fast while the BOXES develops its ability to select proper fuzzy controller through experience.

Consensus-based Cooperative Control for multiple leaders and single follower with interaction nonlinearities (상호작용 비선형성이 있는 다중 리더와 단일 추종자를 위한 일치 기반의 협력 제어)

  • Tack, Han-Ho;Lim, Young-Hun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.25 no.11
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    • pp.1663-1669
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    • 2021
  • This paper considers the cooperative control problem for multiple leaders and a single follower with interactions. The leaders are controllable, and the follower has interactions with all leaders and is controlled by the interactions. Then, we study the cooperative control problem that achieves the consensus by controlling the leaders. The leaders and the follower are modeled by the single-integrator and the double-integrator, respectively, and it is assumed that the interactions have the nonlinearities. The leaders can estimate the interaction between the follower and exchange the estimated information with neighbors. Then, this paper proposes the consensus-based cooperative control algorithm using the information exchange of the estimated interactions and the virtual velocity variables to achieve the velocity consensus. We analyze the convergence of the agents to the common state based on the Lasalle's Invaraince Principle. Finally, we provide the numerical example to validate the theoretical results.

Cooperative Control of Mobile Robot for Carrying Object (물체 운반을 위한 다수 로봇의 협조제어)

  • Jeong, Hee-In;Hoang, Nhat-Minh;Woo, Chang-Jun;Lee, Jangmyung
    • The Journal of Korea Robotics Society
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    • v.10 no.3
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    • pp.139-145
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    • 2015
  • This paper proposed a method of cooperative control of three mobile robots for carrying an object placed on a floor together. Each robot moves to the object independently from its location to a pre-designated location for grasping the object stably. After grasping the common object, the coordination among the robots has been achieved by a master-slave mode. That is, a trajectory planning has been done for the master robot and the distances form the master robot to the two slave robots have been kept constant during the carrying operation. The localization for mobile robots has been implemented using the encoder data and inverse kinematics since the whole system does not have the slippage as much as a single mobile robot. Before the carrying operation, the lifting operations are implemented using the manipulators attached on the top of the mobile robots cooperatively. The real cooperative lifting and carrying operations are implanted to show the feasibility of the master-slave mode control based on the kinematics using the mobile manipulators developed for this research.

Operating Number Control of Compressors Based on Cooperative Logic for a High Efficiency Centrifugal Water Chiller (터보냉동기의 고효율 운전을 위한 협조 방식 기반의 압축기 대수제어)

  • Jeong, Seok-Kwon;Lim, Seung-Kwan;Ryu, Keon-Su
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.5
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    • pp.233-240
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    • 2015
  • This paper discusses compressors operating number control strategy using cooperative logic to cope with variable partial load for high efficiency of a centrifugal water chiller. The cooperative logic is composed of a speed-up and speed-down controller, enabling smooth operation of compressors and equivalent distribution of thermal load in each compressor. This centrifugal water chiller design can be operated with high efficiency without incurring excessive energy waste and large transient phenomena at partial load states. Simulations in MATLAB and experiments in a real chiller system were conducted and verified the high efficiency control of a centrifugal water chiller achieved by the suggested strategy.

Collaborative Sub-channel Allocation with Power Control in Small Cell Networks

  • Yang, Guang;Cao, Yewen;Wang, Deqiang;Xu, Jian;Wu, Changlei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.2
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    • pp.611-627
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    • 2017
  • For enhancing the coverage of wireless networks and increasing the spectrum efficiency, small cell networks (SCNs) are considered to be one of the most prospective schemes. Most of the existing literature on resource allocation among non-cooperative small cell base stations (SBSs) has widely drawn close attention and there are only a small number of the cooperative ideas in SCNs. Based on the motivation, we further investigate the cooperative approach, which is formulated as a coalition formation game with power control algorithm (CFG-PC). First, we formulate the downlink sub-channel resource allocation problem in an SCN as a coalition formation game. Pareto order and utilitarian order are applied to form coalitions respectively. Second, to achieve more availability and efficiency power assignment, we expand and solve the power control using particle swarm optimization (PSO). Finally, with our proposed algorithm, each SBS can cooperatively work and eventually converge to a stable SBS partition. As far as the transmit rate of per SBS and the system rate are concerned respectively, simulation results indicate that our proposed CFG-PC has a significant advantage, relative to a classical coalition formation algorithm and the non-cooperative case.

Effects of a Structure-centered Cooperative Learning Safety Education Program based on Blended Learning for Elementary School Students (초등학생의 블랜디드 러닝 기반 구조중심협동학습을 적용한 안전교육 프로그램 개발 및 효과)

  • Seong, Jeong Hye
    • Research in Community and Public Health Nursing
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    • v.30 no.1
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    • pp.57-68
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    • 2019
  • Purpose: This study was performed to determine effects of a structure-centered cooperative learning safety education program based on blended learning for elementary school students. Methods: The study is developed in nonequivalent control group non-synchronized design. The subjects included 24 sixth grade students in the experimental group and 23 sixth grade students in the control group, respectively. To prevent diffusion of the experiment, it was carried out from May 20th to June 24th in 2015 with the control group and the other from August 26th to September 30th in 2015 with the experimental group. It was performed on experimental group after the structure-centered cooperative learning safety education program based on blended learning once a week for 6weeks. Data were analyzed by using descriptive statistics, paired t-test and independent t-test. Results: After the intervention, the experimental group showed significant increases in the self-directed learning attitudes and safety behavior compared to the control group except for the academic self-efficacy. Conclusion: The results indicate that the structure-centered cooperative learning safety education program based on blended learning program is effective in safety education for 6th graders.

Experimental Analysis on Influences of Kinesthetic and Visual Sensations in a Human-Machine Cooperative System Considering Machine Dynamics

  • Tomonori, Yamamoto;Yoshiki, Matsuo;Takeshi, Inaba
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.1553-1558
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    • 2003
  • The authors investigate influences of manipulator dynamics on and roles of kinesthetic sensation and visual sensation in a Human-Machine Cooperative System (HMCS). At first, the general structure and essential transfer functions of HMCSs are described based on the previous work. Then, after showing theoretical treatment of manipulator dynamics, this paper analyzes the influences on HMCSs in two cases: one is the control design focusing on tool dynamics and reaction force transfer function, and the other is that specifies maneuver transfer function and transfer function for object dynamics variation. In addition to conventional experiments only employing kinesthetic sensation, other experiments with both kinesthetic and visual sensations are performed to examine difference in the roles of these sensations and the validity of the design without the visual sensation.

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