• Journal of the Korean School Mathematics Society
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• v.9 no.1
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• pp.1-17
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• 2006

This thesis analyzed the effects of cooperative learning blended with TAI(Team Assisted Individualization) and STAD(Student Team Achievement Division) models on the students' ability of problem solving in mathematics in order to discover what kind of effects would give to their ability of that, and would promote their disposition and attitude to learn mathematics. The results of this study were as follows : First, the learning method blended with TAI and STAD models was more effective in the students' ability of problem solving in mathematics than traditional learning method because of the blended model's characteristics; positive interdependence, individual accountability, team recognition, curriculum materials. Second, the learning method blended with TAI and STAD models was more effective in sub-elements - self-confidence, adaptability, will, curiosity and value - of mathematical disposition than traditional learning method. And the learning method blended with TAI and STAD models was more effective in sub-elements - self-consciousness of mathematics and interests - of mathematical attitude than traditional learning method. In conclusion, the learning method blended with TAI and STAD models could affect to not only the students' ability of problem solving in mathematics but also the students' several affective factors.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.10
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• pp.2455-2472
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• 2012

Although underlay spectrum sharing has been shown as a promising technique to promote the spectrum utilization in cognitive radio networks (CRNs), it may suffer bad secondary performance due to the strict power constraints imposed at secondary systems and the interference from primary systems. In this paper, we propose a two-phase based cooperative transmission protocol with the interference cancellation (IC) and best-relay selection to improve the secondary performance in underlay models under stringent power constraints while ensuring the primary quality-of-service (QoS). In the proposed protocol, IC is employed at both the secondary relays and the secondary destination, where the IC-based best-relay selection and cooperative relaying schemes are well developed to reduce the interference from primary systems. The closed-form expression of secondary outage probability is derived for the proposed protocol over Rayleigh fading channels. Simulation results show that, with a guaranteed primary outage probability, the proposed protocol can achieve not only lower secondary outage probability but also higher secondary diversity order than the traditional underlay case.

• Journal of The Korean Association of Information Education
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• v.6 no.2
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• pp.154-162
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• 2002

In a small-scale class, children gradually lose interests in studying and develop negative and passive attitudes in class activities due to the uniform education. Although many cooperative instruction WBI models are studied and designed, there has not been any research on cooperative instruction model appropriate for a small-scale class. In this study, instructors participate in classes, each in connection with other small-scale classes, and WWW based cooperative instruction model, WIEZ, which can affect students' learning attitude on long-term basis, was designed and embodied. Currently, WIEZ is being under experimental test in three schools at Kyung-nam where instructors design classes, and students divided into groups participate in classes in this system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.53-58
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• 2011

Recently, MIMO technology, which can improve data rate, link reliability and diversity order, has been widely studied. However, due to the limitation of size, cost and complexity, it is difficult to equip multiple antennas in mobile devices. To overcome this problem, the cooperative communication scheme has been proposed. In this scheme, each terminal shares its single antenna to form a virtual MIMO environment. However, in conventional cooperative scheme, e.g, decode-and-forward, amplify and forward, the spectral efficiency is decreased if there are many terminals taking part in the cooperation. Therefore, the incremental relaying scheme has been proposed to solve this problem. In this paper, we consider various models using incremental relaying technique. In addition, the position of relay is investigated in order to obtain optimal performance.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.97-108
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• 2010

Recent patterns of diversification of a disaster, depending on the size of the larger trend, quick and efficient response to disaster prevention, to increase the importance and role of advanced equipment and technology of fire protection industry is becoming more, over market size 11 trillion won and 10 million workers in industries of national importance, but to exceed, As most SMEs compared to other industries are backwardness. Therefore, in this study closely the characteristics of the fire protection industry analysis, the systematization of theoretical models of the finance cooperative system considering the characteristics of fire protection industry and provider the fosterage, they will contribute to independent economic activity and industrial development for operators to use the finance cooperative system of fire protection industry.

• International Journal of Advanced Culture Technology
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• v.5 no.1
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• pp.1-8
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• 2017

The purpose of the present study is to examine the effect of civic cooperation with the police on the number of crime that the police must solve by conducting simulation based on system dynamics. The study sets police oriented-policing model and police-citizen cooperative model to investigate the effect of civic cooperation with the police. As a result of the simulation, the police oriented-policing model shows that the number of crime that police must solve is increasing over time, while the police-citizen cooperative model shows that the number of crime that must be solved by the police is keeping it stable in the increase of crimes. Comparing both models, civic cooperation with the police is more effective in reducing or deterring crime than police oriented-policing activity. The study proves that building cooperative relationship between citizens and the police can become a strategic method for controlling crime effectively without a rapid increase in police finance. It is meaningful in terms of presenting a dynamic change of interaction for reducing crimes between civic cooperation with the police and policing activity of the police over time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.2838-2858
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• 2019

Traditional channel models for vehicle-to-vehicle (V2V) communication usually assume fixed velocity in static scattering environment. In the realistic scenarios, however, time-variant velocity for V2V results in non-stationary statistical properties of wireless channels. Dynamic scatterers with random velocities and directions have been always utilized to depict the non-stationary statistical properties of the channel. In this paper, a non-stationary geometry-based cooperative scattering channel model is proposed for multiple-input multiple-output (MIMO) V2V communication systems, where a birth-death process is used to capture the appearance and disappearance dynamic properties of moving scatterers that reflect the time-variant time correlation and Doppler spectrum characteristics. Moreover, our model has more straight and concise to study the impact of the vehicular traffic density on channel characteristics and thus avoid complicated procedure in deriving the analytical expressions of the channel parameters and functions. The numerical results validate our analysis and demonstrate that setting important parameters of our model can appropriately build up more purposeful measurement campaigns in the future.

• 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.

• The Korean Journal of Franchise Management
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• v.3 no.2
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• pp.1-19
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• 2012

This study intends to suggest the cooperative, win-win collaboration, as methods for settling disputes with the existing self-employed people over back-street business areas and disputes and conflicts between a franchiser and franchisees. In addition, it intends to analyze the Dunkin' Donuts purchasing cooperative in the US, where the franchising industry has been well developed; and to find the implications of cooperation strategies between Dunkin' Donuts and its franchisees that may be helpful for the South Korea's franchising industry. This study tries to discover a new model of the Korean-style franchise cooperative out of the basic principles and practice guidelines of cooperatives ranging from an early American franchise cooperative in 1955 to ARCOP, KFC, and Dunkin' Doughnuts in the late 1970s. Further, it looks into successful programs of a purchasing cooperative at Dunkin' Donuts such as TDP (Total Distribution Program), SFP (Shortening Futures Program) and DCP (Distribution Commitment Program). The case of the US Dunkin' Donuts, which operates the purchasing cooperative, suggests the following for the improvement of franchisees' profitability. First, relations of cooperation rather than of power are necessary between a franchiser and franchisees. Second, mutual solidarity of franchisees is necessary. Third, problems proper to the Korean franchise system should be improved. Fourth, an entrepreneurial spirit of going together rather than going fast is required. Fifth, complete satisfaction management is required. Considering different system environments between the two countries such as quantitative expansion within a short franchising history of 30 years or so and franchise profit models, there is a limit to generalizing down to a successful model of the win-win partnership cooperative. It is hoped that the sustainable management of the domestic franchising industry will be promoted in the future through the in-depth analysis of successful cooperatives.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.44-49
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• 2006

In this study, the resolution capabilities of electrical resistivity tomography (ERT) in the monitoring of $CO_2$ injection are investigated. The pole-pole and bipole-bipole electrode configuration types are used between two uncased boreholes straddling the $CO_2$ plume. Forward responses for an initial pre-injection model and three models for subsequent stages of $CO_2$ injection are calculated for the two different electrode configuration types, noise is added and the theoretical data are inverted with both L1- and L2-norm optimisation. The results show that $CO_2$ volumes over a certain threshold can be detected with confidence. The L1-norm proved superior to the L2-norm in most instances. Normalisation of the inverted models with the pre-injection inverse model gives good images of the regions of changing resistivity, and an integrated measure of the total change in resistivity proves to be a valid measure of the total injected volume.