• Journal of information and communication convergence engineering
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• v.20 no.4
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• pp.250-258
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• 2022

The emerging scope of the Internet-of-Things (IoT) has piqued the interest of industry and academia in recent times. Therefore, security becomes the main issue to prevent the possibility of cyberattacks. Jamming attacks are threads that can affect performance and cause significant problems for IoT device. This study explores a smart jamming attack (coalition attack) in which the attackers were previously a part of the legitimate network and are now back to attack it based on the gained knowledge. These attackers regroup into a coalition and begin exchanging information about the legitimate network to launch attacks based on the gained knowledge. Our system enables jammer nodes to select the optimal transmission rates for attacks based on the attack probability table, which contains the most probable link transmission rate between nodes in the legitimate network. The table is updated constantly throughout the life cycle of the coalition. The simulation results show that a coalition of jammers can cause highly successful attacks.

• The KIPS Transactions:PartC
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• v.17C no.4
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• pp.385-390
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• 2010

Fair and efficient bandwidth allocation methods using the coalition game theory and the bargaining game theory following the axiomatic approach have been proposed when sending nodes with different traffic input rate try to share the bandwidth. These methods satisfy the axiomatic fairness provided by the mathematical ground of the game theories. However, since the axioms of the two game models are different from one another, the allocated bandwidths to each sending nodes become different even in the same communication environments. Thus, in this paper, we model the bandwidth allocation problem with these game theories, and quantitatively compare and analyze the allocated bandwidth and loss rate of each sending nodes in various communication environments. The results show that the bargaining game allocates relatively less bandwidth to a node with a higher sending rate than that with a lower sending rate while coalition game allocates bandwidth according to the sending rate of each node.

• Journal of KIISE:Software and Applications
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• v.27 no.3
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• pp.257-265
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• 2000

There is much selective confliction in nature where selfish and rational individuals exists. Iterated Prisoner's Dilemma (IPD) game deals with this problem, and has been used to study on the evolution of cooperation in social, economic and biological systems. So far, there has been much work about the relationship of the number of players and cooperation, strategy learning as a machine learning and the effect of payoff functions to cooperation. In this paper, We attempt to investigate the cooperative coalition size according to payoff functions, and observe the relationship of localization and the evolution of cooperation in NIPD (N-player IPD) game. Experimental results indicate that cooperative coalition size increases as the gradient of the payoff function for cooperation becomes steeper than that of defector's payoff function, or as the minimum coalition size gets smaller, Moreover, the smaller the neighborhood of interaction is, the higher the cooperative coalition emerges through the evolution of population.

• The Journal of Information Systems
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• v.22 no.1
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• pp.165-180
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• 2013

Using long-term panel data of OKCashbag, this study analyzes whether learning effect influencing in effectiveness of coalition loyalty program exists. We found that there is learning effect in the behavior of loyalty program customers, and discovered that learning effect appears more greatly in using (redeeming) behavior than accumulating behavior. The authors also found a long-lasting structural changes in the pattern of point redemption after a major marketing activities associated with the act of using points. The results of this research can contribute to suggest direction to the future researches to examine differences of learning effect according to demographic (gender, age, region, ect.) and transactional (frequency or scale in point accumulation and redemption etc.) characteristics.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.370-374
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• 2004

This comparative study means the case studies about not only coalition and partnership but also competition between high speed rail and other transportation modes. Therefore, I reviewed the each case about some countries and tried to develop for making some measurement. However, in this study, some bounds and limits exists owing to the descriptive reviews but not detailed analyses. Hereafter, I am planning to consider the management plan for efficient railway coalition with other transportation at the rail station and other terminal facilities.

• Journal of Contemporary Eastern Asia
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• v.3 no.2
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• pp.1-6
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• 2004

On 27 June 2004, some one million voters went to the polls in Mongolia to elect 76 members of the Great State Hural, Mongolia's parliament. It was the fourth election held in Mongolia under the 1992 constitution. In the previous election, the former communist MPRP won a landslide, ousting the government of former democracy activists. Under the MPRP, Mongolia's economy performed extraordinary well. Surprisingly, the ruling Mongolian People's Revolutionary Party (MPRP) lost its two-thirds majority and half its parliamentarians in the 2004 election. But the Motherland Democracy Coalition (MDC), a coalition of Mongolia's most influential opposition parties, fell short of achieving a majority of its own. After the election, a grand coalition government was formed, paving the way for profound legal, social, and economic reforms.

• Journal of the Society of Disaster Information
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• v.10 no.4
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• pp.528-535
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• 2014

The objectives of this study is applied to the process of established fire scientific research organization and to be equipped capabilities to develop fire organization, so finally to offer promising fire organization in the future.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.7
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• pp.3413-3430
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• 2017

With the fast increasing popularity of mobile services, ubiquitous mobile devices with enhanced sensing capabilities collect and share local information towards a common goal. The recent Mobile Crowd Sensing (MCS) paradigm enables a broad range of mobile applications and undoubtedly revolutionizes many sectors of our life. A critical challenge for the MCS paradigm is to induce mobile devices to be workers providing sensing services. In this study, we examine the problem of sensing task assignment to maximize the overall performance in MCS system while ensuring reciprocal advantages among mobile devices. Based on the overlapping coalition game model, we propose a novel workload determination scheme for each individual device. The proposed scheme can effectively decompose the complex optimization problem and obtains an effective solution using the interactive learning process. Finally, we have conducted extensive simulations, and the results demonstrate that the proposed scheme achieves a fair tradeoff solution between the MCS performance and the profit of individual devices.

• Journal of Information Technology Services
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• v.15 no.1
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• pp.299-319
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• 2016

This study first introduces platform services and their business models. On the basis of the concepts of business ecosystem, we present a framework for distinguishing types of the platform service business models. Two key characteristics of business ecosystems-ecosystem configuration and value production process-are employed as fundamental dimensions for constructing typology. In particular, we also present the notion of value ecosystem, where not a single platform provider but a federation of platforms constitutes a virtual platform and completes a service system. The value ecosystem represents two distinct types of platform service business models : meta-platform ecosystem and platform coalition ecosystem. They show different governance structure in the platform federation and service flows across the ecosystem. We present detailed analyses of these two value ecosystems focusing on relevant cases of e-payment FinTech : Apple Pay as an example of meta-platform and Kakao Pay for platform coalition. Our conceptual typology contributes to platforms' proper strategy formulation and presents policy implications to, for example, platform neutrality.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1415-1423
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• 2016

Interference in device-to-device (D2D) communication underlaying cellular network needs to be elaborately investigated because of channel sharing. The objective is to improve the quality of D2D communications while maintaining high performance for cellular users. In this paper, we solve the above problem by jointly considering channel allocation and power control using coalition formation game. Our cooperative game theoric approach allows to enhance network-wide performance. We design a merge-and-split algorithm to deal with the complexity of the combinatorial structure in coalition formation problem. The analytical and numerical results show that our algorithm converges to a stable point which achieves high network performance.