• International Journal of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.104-110
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• 2020

In the 4th Industrial Revolution, the competitiveness of the software industry is important, and as a solution to fundamentally secure the competitiveness of the software industry, education classes should be provided to educate high quality software personnel in educational institutions. Despite this social situation, software-related classes in universities are largely composed of competitive or individual learning structures. Cooperative learning is a learning model that can complement the problems of competitive and individual learning. Cooperative learning is more effective in improving academic achievement than individual or competitive learning. In addition, most learners have the advantage of having a more desirable self-image by having a successful experience. In this paper, we apply a pair check model, which is a type of cooperative learning, in operating system classes. In addition, the class procedure and instruction plan are designed to apply the pair check model. We analyze the test results to analyze the performance of the cooperative learning model.

• International Journal of Aeronautical and Space Sciences
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• v.15 no.3
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• pp.281-292
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• 2014

We propose a novel cooperative guidance law design method based on the finite time disturbance observer (FTDO) for multiple near space interceptors (NSIs) with impact time control. Initially, we construct a cooperative guidance model with head pursuit, and employ the FTDO to estimate the system disturbance caused by target maneuvering. We subsequently separate the cooperative guidance process into two stages, and develop the normal acceleration command based on the super-twisting algorithm (STA) and disturbance estimated value, to ensure the convergence of the relative distance. Then, we also design the acceleration command along the line-of-sight (LOS), based on the nonsingular fast terminal sliding mode (NFTSM) control, to ensure that all the NSIs simultaneously hit the target. Furthermore, we prove the stability of the closed-loop guidance system, based on the Lyapunov theory. Finally, our simulation results of a three-to-one interception scenario show that the proposed cooperative guidance scheme makes all the NSIs hit the target at the same time.

• The Journal of the Korea Contents Association
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• v.8 no.10
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• pp.381-390
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• 2008

As computer technology is in progress and many educational methods have been emerged, web-based cooperative learning and educational games have gained a lot of interests. Some cooperative learning systems and game-based educational systems have been suggested, but few cooperative learning systems use games. This paper builds a new web-based cooperative learning system using games that enables learners to actively participate and have high interests in learning. In our system, cooperation study is performed in each group and a group member competes with other group members using games. A crossword puzzle game is adopted because of ease to use and fit with cooperative learning scenarios. Our suggested system is implemented and used by two classes of high school students to evaluate this system. The experimental results show that our system effectively improve students' learning interests and increase their academic achievement.

• The Journal of Korean Physical Therapy
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• v.16 no.3
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• pp.32-49
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• 2004

The primary purpose of this study was to provide the basic materials for C.V.A inpatients' actual use of medical service at the hospital with both the western and oriental medical department and the attitude on cooperative treatment. The results of this study were as follow: First, the subjects' general characteristics including job, monthly mean income and age made statistical differences to their pathological characteristics such as part of primary paralysis, detailed name of disease and cause of elicitation. Second, their general characteristics including religion and job produce statistical difference to their actual use of medical service, like medical institution form, term of treatment and type of medical institution at first-aid. Third, through the awareness of cooperative treatment system, the effect of C.V.A treatment and the shorten of the C.V.A treatment term were higher at oriental medical department inpatients and cooperative treatment serviced inpatients than western medical department inpatients and cooperative treatment non-serviced inpatients. Fourth, the biggest problem on current dual medical system is increase medical expenses and the biggest reason on not vitalized cooperative service is prejudice of both parts.

• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.75-77
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• 2012

In recent years, with the development of various transportation, railway evolved a lot. With advanced rail system, efficient communication system was required. for the delivery of accurate information of railway communications systems. Accordingly, railway communication system has evolved in a variety of ways. Cooperative communication method was proposed railway minimize the effects of fading in wireless communications and more efficient communication. In this paper, we present cooperative transmission techniques and channel characteristics and examples, and simulation results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.287-293
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• 2013

Cognitive radio has been recently proposed to dynamically access unused-spectrum. The CR users can share the same frequency band with the primary user without interference to each other. Usually each CR user needs to determine spectrum availability by itself depending only on its local observations. But uncertainty communication environment effects can be mitigated so that the detection probability is improved in a heavily shadowed environment. Soft detection is a primary user detection method of cooperative cognitive radio networks. In our research, we will improve system detection probability by using optimal cooperative node selection algorithm. New algorithm can find optimal number of cooperative sensing nodes for cooperative soft detection by using maximum ratio combining (MRC) method. Through analysis, proposed cooperative node selection algorithm can select optimal node for cooperative sensing according to the system requirement and improve the system detection probability.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.251-255
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• 2012

In recent years, according to improvement of various vehicle instruments, railway also has been developed in various fields. As a result, to transmit accurate information to each railway system, the efficient communication system is required. In railway communication system, mitigation of wireless fading is very important. So, in this paper we introduced the cooperative relay channel model and cooperative relay scheme. Also we analyzed and simulated the cooperative relay scheme which is suitable for railway communication systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11C
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• pp.889-895
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• 2010

MIMO system generally requires more than one antenna at the communication device. However, many wireless devices are limited by size, cost or hardware complexity to one antenna. To overcome such restrictions, we used a new technique, called cooperative communication. We propose a new cooperative transmission strategy system using cross-layer coding method base on H-ARQ for optimal communication. Proposed cooperative H-ARQ system that can improve the above problems and can get the better performance. In proposed cooperative system with H-ARQ method, if the received signal from source node is satisfied by the destination preferentially, the destination transmit ACK message to both relay node and source node, and then recovers the received signal. In addition, if ARQ message indicates NACK message, relay node operates selective retransmission. Based on the simulation results in aspect to BER performance and throughput, the proposed method which combined cooperative system with H-ARQ based on cross-layer coding can improve spectral efficiency reliability of system compared with that of general one by one system.

• Journal of Communications and Networks
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• v.14 no.5
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• pp.524-532
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• 2012

In this paper, we present the performance evaluation of the reliable cooperative media access control (RCO-MAC) protocol, which has been proposed in [1] by us in order to enhance system throughput in bad wireless channel environments. The performance of this protocol is evaluated with computer simulation as well as mathematical analysis in this paper. The system throughput, two types of average delays, average channel access delay, and average system delay, which includes the queuing delay in the buffer, are used as performance metrics. In addition, two different traffic models are used for performance evaluation: The saturated traffic model for computing system throughput and average channel access delay, and the exponential data generation model for calculating average system delay. The numerical results show that the RCO-MAC protocol proposed by us provides over 20% more system throughput than the relay distributed coordination function (rDCF) scheme. The numerical results show that the RCO-MAC protocol provides a slightly higher average channel access delay over a greater number of source nodes than the rDCF. This is because a greater number of source nodes provide more opportunities for cooperative request to send (CRTS) frame collisions and because the value of the related retransmission timer is greater in the RCO-MAC protocol than in the rDCF protocol. The numerical results also confirm that the RCO-MAC protocol provides better average system delay over the whole gamut of the number of source nodes than the rDCF protocol.

• Journal of the military operations research society of Korea
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• v.27 no.1
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• pp.114-127
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• 2001

To support cooperative work in various scenes by computer systems, functions of sharing personalization, observation and control are needed. Especially, in advanced cooperative work, people have various position so that sometimes one person needs to restrict behavior of another. In this paper, we describe representation of access restriction of hypermedia system, which is framework of CSCW(Computer-Supported Cooperative Works) system we developed and propose a way to go on working cooperatively with people, restricting others.