• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권7호
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• pp.2231-2245
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• 2014

Cognitive Radio (CR) has very promising potential to improve spectrum utilization by allowing unlicensed Secondary Users (SUs) to access the spectrum dynamically without disturbing licensed Primary Users (PUs). Mitigating interference is a fundamental problem in CR scenarios. This is particularly problematic for deploying CR in cellular networks, when users are located at the cell edge, as the inter-cell interference mitigation and frequency reuse are critical requirements for both PUs and SUs. Further cellular networks require higher cell edge performance, then SUs will meet more challenges than PUs. To solve the performance decrease for SUs at the cell edge, a novel Dynamic Spectrum Allocation (DSA) scheme based on Game Theory is proposed in this paper. Full frequency reuse can be realized as well as inter-cell interference mitigated according to SUs' sensing, measurement and interaction in this scheme. A joint power/channel allocation algorithm is proposed to improve both cell-edge user experience and network performance through distributed pricing calculation and exchange based on game theory. Analytical proof is presented and simulation results show that the proposed scheme achieves high efficiency of spectrum usage and improvement of cell edge SUs' performance.

• 한국멀티미디어학회논문지
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• 제17권4호
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• pp.526-534
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• 2014

Most of the multiplayer games available online are based on a client-server architecture because this architecture gives better administration control to the game providers than peer-to-peer architecture. In this architecture, the server is responsible for all the communication between the connected clients. The weakness of this architecture is its bandwidth requirement and scalability. Peer-to-peer architectures have then been proposed to solve these issues. In this paper, we propose a hybrid client-server architecture in which the game state is partially shared by the mobile terminal to achieve consistency among different players. Like a peer-to-peer architecture, this architecture uses client-side capacities to reduce bandwidth requirements for the server and improves consistency in wireless networks. Client events have different timeliness and consistency requirements according to their nature in the game world. These requirements lead to tasks with different priorities on CPU processing. In the proposed architecture, either the server or the client applies consistency mechanism according to the priority level. Simulation experiments show that the bandwidth of the server in this architecture is smaller than that of the client-server architecture. As a result, the server in the proposed architecture can accommodate more clients with enhancing the scalability.

• 정보과학회 논문지
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• 제42권11호
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• pp.1423-1429
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• 2015

최근, 인터넷이 확장됨에 따라 새로운 가치를 생산하는 활용성이 증가되고 있다. 사물인터넷(Internet of Things)은 미래인터넷의 새로운 개념으로, 네트워크 물리적 객체들의 상호연결을 강조하여 최근 크게 주목받고 있으나, 사물인터넷상에서 서로 다른 서비스품질 요구를 만족시키기란 상당히 어렵다. 본 논문에서는, 사물인터넷 시스템의 다양한 서비스품질요구를 만족시킬 수 있는 효율적인 자원할당 방법을 제시한다. 제안된 방법은 마르코프 게임 모델에 기초하여 시스템 성능을 최대화할 수 있도록 효율적으로 사물인터넷 자원들을 할당한다. 시뮬레이션 결과, 제안된 방법은 현재의 사물인터넷 상황에서 기존의 방식에 비해 뛰어난 성능을 보여준다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권6호
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• pp.1926-1945
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• 2014

In this paper, we propose a distributed signal subspace interference alignment algorithm for single beam K-user ($3K{\geq}$) MIMO interference channel based on sum rate maximization and game theory. A framework of game theory is provided to study relationship between interference signal subspace and altruistic-egoistic bayesian game cost function. We demonstrate that the asymptotic interference alignment under proposed scheme can be realized through a numerical algorithm using local channel state information at transmitters and receivers. Simulation results show that the proposed scheme can achieve the total degrees of freedom that is equivalent to the Cadambe-Jafar interference alignment algorithms with perfect channel state information. Furthermore, proposed scheme can effectively minimize leakage interference in desired signal subspace at each receiver and obtain a moderate average sum rate performance compared with several existing interference alignment schemes.

• 한국게임학회 논문지
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• 제17권6호
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• pp.165-172
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• 2017

다양한 플랫폼에 따라 게임을 개발하는 데에는 중복되는 작업들이 있는 것 같다. 각 플랫폼에 따라 데이터를 관리하고 처리하는 유사한 작업이 포함되는데, 이는 개발기간에도 영향을 미친다. 본 논문은 최근 유행하고 있는 전투 시뮬레이션 게임을 멀티 플랫폼 기반으로 서버를 설계 하고 제작하여 플랫폼 형태와 상관없이 동일한 서버와 같은 전투 시뮬레이션의 결과를 볼 수 있는 서버 프레임 워크를 제안한다. JSON 데이터 포맷을 사용하여 속성-값 쌍으로 이루어진 프로토콜을 사용하여 디버깅하기 편하게 설계 하였다. 프로그래밍 언어에 독립적이기 때문에 다양한 언어와 통신을 할 수 있는 장점도 가지고 있다. 서버는 아마존 서버를 이용하여 쉽게 서버 구조를 확장하거나 서버 스펙을 업그레이드 할 수 있는 모델을 제안한다.

• Journal of Communications and Networks
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• 제16권2호
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• pp.183-192
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• 2014

This paper proposes a payment-based power control scheme using non-cooperative game with a novel pricing function in cognitive radio networks (CRNs). The proposed algorithm considers the fairness of power control among second users (SUs) where the value of per SU' signal to noise ratio (SINR) or distance between SU and SU station is used as reference for punishment price setting. Due to the effect of uncertainty fading environment, the system is unable to get the link gain coefficient to control SUs' transmission power accurately, so the quality of service (QoS) requirements of SUs may not be guaranteed, and the existence of Nash equilibrium (NE) is not ensured. Therefore, an alternative iterative scheme with sliding model is presented for the non-cooperative power control game algorithm. Simulation results show that the pricing policy using SUs' SINR as price punishment reference can improve total throughput, ensure fairness and reduce total transmission power in CRNs.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2000년도 춘계학술대회 학술발표 논문집
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• pp.292-297
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• 2000

본 논문은 10개 교차로를 연동제어를 할 수 있는 새로운 교통체제 개념을 제안한다. 예를 들어서 오늘 야구경기가 8시경에 열린다고 하면 야구경기가 열리기전 1시간 흑은 1시간 30분전에 교통량이 증가할 것이다. 이럴때에는 아무리 우수한 전자 신호등 시스템도 최적녹색시간을 예측 할 수 없다. 그러므로, 본 논문에서는 평균 승용차 대기시간을 최소화하고 평균 주행속도를 향상하기 위해서 퍼지규칙 및 신경망을 이용한다. 모의실험결과 제안된 연동 녹색시간이 연동 녹색시간을 고려하지 않은 전자신호등보다 평균 승용차 대기시간을 줄일 수 있음을 입증했다.

• ETRI Journal
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• 제34권3호
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• pp.341-351
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• 2012

We deal with a resource allocation problem for multimedia service discrimination in wireless networks. We assume that a service provider allocates network resources to users who can choose and access one of the discriminated services. To express the rational service selection of users, the utility function of users is devised to reflect both service quality and cost. Regarding the utility function of a service provider, total profit and efficiency of resource usage have been considered. The proposed service discrimination framework is composed of two game models. An outer model is a repeated Stackelberg game between a service provider and a user group, while an inner model is a service selection game among users, which is solved by adopting the Kalai-Smorodinsky bargaining solution. Through simulation experiments, we compare the proposed framework with existing resource allocation methods according to user cost sensitivity. The proposed framework performed better than existing frameworks in terms of total profit and fairness.

• 한국군사과학기술학회지
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• 제23권4호
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• pp.337-345
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• 2020

The Weapon-Target Assignment(WTA) problem can be formulated as an optimization problem that minimize the threat of targets. Existing methods consider the trade-off between optimality and execution time to meet the various mission objectives. We propose a multi-agent reinforcement learning algorithm for WTA based on mean field game to solve the problem in real-time with nearly optimal accuracy. Mean field game is a recent method introduced to relieve the curse of dimensionality in multi-agent learning algorithm. In addition, previous reinforcement learning models for WTA generally do not consider weapon interference, which may be critical in real world operations. Therefore, we modify the reward function to discourage the crossing of weapon trajectories. The feasibility of the proposed method was verified through simulation of a WTA problem with multiple targets in realtime and the proposed algorithm can assign the weapons to all targets without crossing trajectories of weapons.

• 대한산업공학회지
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• 제41권5호
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• pp.414-424
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• 2015

In this research, we consider a smart grid network of electricity with multiple consumers connected to a monopolistic provider. Each consumer can be informed the real time price changes through the smart meter and updates his consumption schedule to minimize the energy consumption expenditures by which the required power demand should be satisfied under the given real time pricing scheme. This real-time decision making problem has been recently studied through game-theoretic approach. The present paper contributes to the existing literature by incorporating storage appliance into the set of available household appliances which has somewhat distinctive functions compared to other types of appliances and would be regarded to play a significant role in energy consumption scheduling for the future smart grid. We propose a game-theoretic algorithm which could draw the optimal energy consumption scheduling for each household appliances including storage. Results on simulation data showed that the storage contributed to increase the efficiency of energy consumption pattern in the viewpoint of not only individual consumer but also whole system.