• Journal of Communications and Networks
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• v.10 no.2
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• pp.163-174
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• 2008

Performance of downlink transmission strategies exploiting cooperative transmit diversity is investigated for distributed multiple-input single-output (MISO) systems, for which geographically distributed remote antennas (RA) in a cell can either communicate with distinct mobile stations (MS) or cooperate for a common MS. Statistical characteristics in terms of the signal-to-interference-plus-noise ratio (SINR) and the achievable capacity are analyzed for both cooperative and non-cooperative transmission schemes, and the preferred mode of operation for given channel conditions is presented using the analysis result. In particular, we determine an exact amount of the maximum achievable gain in capacity when RAs for signal transmission are selected based on the instantaneous channel condition, by deriving a general expression for the SINR of such antenna selection based transmission. For important special cases of selecting a single RA for non-cooperative transmission and selecting two RAs for cooperative transmission among three RAs surrounding the MS, closed-form formulas are presented for the SINR and capacity distributions.

• International Journal of Control, Automation, and Systems
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• v.6 no.3
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• pp.401-412
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• 2008

This paper discusses a design methodology of cooperative path planning for dynamical multi-agent systems with spatial and temporal constraints. The cooperative behavior of the multi-agent systems is specified in terms of the objective function in an optimization formulation. The path of achieving cooperative tasks is then generated by the optimization formulation constructed based on a differential flatness approach. Three scenarios of multi-agent tasking are proposed at the cooperative task planning framework. Given agent dynamics, both spatial and temporal constraints are considered in the path planning. The path planning algorithm first finds trajectory curves in a lower-dimensional space and then parameterizes the curves by a set of B-spline representations. The coefficients of the B-spline curves are further solved by a sequential quadratic programming solver to achieve the optimization objective and satisfy these constraints. Finally, several illustrative examples of cooperative path/task planning are presented.

• The Pure and Applied Mathematics
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• v.24 no.4
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• pp.201-209
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• 2017

We prove convergence properties of the global solutions to the cooperative cross-diffusion system with the intra-specific cooperative pressures dominated by the inter-specific competition pressures and the inter-specific cooperative pressures dominated by intra-specific competition pressures. Under these conditions the $W^1_2-bound$ and the time global existence of the solution for the cooperative cross-diffusion system have been obtained in [10]. In the present paper the convergence of the global solution is established for the cooperative cross-diffusion system with large diffusion coefficients.

• Journal of Korean Elementary Science Education
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• v.20 no.2
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• pp.165-175
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• 2001

The study aimed to examine the effects of cooperative learning in science teaching on scientific knowledge, inquiry ability, and science - related attitudes. This study has carried out LT strategy. The cooperative learning was applied to the experimental group for 8 weeks with worksheets developed for this study, The results were statistically analyzed by SPSS. The results are as follows: Students of cooperative learning made significant progress in scientific knowledge(p<.05), inquiry ability(p<.01), and science - related attitudes(p<.05). The students in the cooperative classes have shown that the cooperative learning was good for causing interest. inducing active participation, and helping students' learning. and students showed strong wish for the continuous cooperative loaming.

• International journal of advanced smart convergence
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• v.7 no.1
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• pp.15-23
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• 2018

Spectrum allocation is a key operation in cognitive radio networks (CRNs), where secondary users (SUs) are usually selfish - to achieve itself utility maximization. In view of this context, much prior lit literature proposed spectrum allocation base on non-cooperative game models. However, the most of them proposed non-cooperative game models based on complete information of CRNs. In practical, primary users (PUs) in a dynamic wireless environment with noise uncertainty, shadowing, and fading is difficult to attain a complete information about them. In this paper, we propose a non-cooperative game joint hidden markov model scheme for spectrum allocation in CRNs. Firstly, we propose a new hidden markov model for SUs to predict the sensing results of competitors. Then, we introduce the proposed hidden markov model into the non-cooperative game. That is, it predicts the sensing results of competitors before the non-cooperative game. The simulation results show that the proposed scheme improves the energy efficiency of networks and utilization of SUs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.956-958
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• 2010

The paper considers MIMO two-way scheme to optimize the end to end capacity in local wireless mesh network. The basic idea is to perform data transmission via intermediate cooperative nodes and cooperative relay therefore higher throughput can be achieved. Each node is equipped with multiple antennas, and has two time slots one for transmission (Tx) and the other is reception (Rx), which are arranged alternatively in the network. In the conventional SISO network, it takes at least four time slots to accomplish the function of two-way relay. Moreover, cooperative technique is used in order to enhance multiplexing of forward and backward streams.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.19 no.1
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• pp.89-111
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• 2008

This study intends to research model to nation-wide Library Cooperative System in Korea and to make legal and institutional devices. For this purpose, it analyzes and investigate theories, types and model of Library Cooperation; and current status and problems in operations of major Cooperative System in all library types. The results developed new model of national wide Cooperative System on the basis of region Cooperative System.

• ETRI Journal
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• v.36 no.2
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• pp.280-285
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• 2014

In this paper, the optimal power control problem in a cooperative relay network is investigated and a new power control scheme is proposed based on a non-cooperative differential game. Optimal power allocated to each node for a relay is formulated using the Nash equilibrium in this paper, considering both the throughput and energy efficiency together. It is proved that the non-cooperative differential game algorithm is applicable and the optimal power level can be achieved.

• Korean Management Science Review
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• v.11 no.3
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• pp.169-183
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• 1994

Government provides for special considerations to technology transfer and cooperative R&D between Government-Supported Research Institutes(GSRI) and Private sector. Nevertheless, the results of many cooperative R&D stagnates in the innovation. This paper examines the reasons for the current low level of the effectiveness of cooperative R&D between GSRIs and small & medium firms. Recommendation are made to enhance the effectiveness of cooperative R & D.

• Korean Journal of Mathematics
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• v.20 no.4
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• pp.463-475
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• 2012

Cooperation is an essential element in mathematics education with independence. We observe cooperative learning and apply it to the education spot. We conducted cooperative learning experiment with students who were not ready for the prerequisite learning of college mathematics. We try to make up the prerequisite learning through collaborative learning to them. We discuss how cooperative learning affects the students who were not ready for the prerequisite learning of college mathematics.