• Journal of KIISE:Software and Applications
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• v.31 no.2
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• pp.101-110
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• 2004

In dynamic systems, such as social and economic systems, complex interactions emerge among its members. In that case, their behaviors become adaptive according to Changing environment. In many cases, an individual's behaviors can be modeled by a stimulus-response system in a dynamic environment. In this paper, we use the Iterated Prisoner's Dilemma (IPD) game, which is simple yet capable of dealing with complex problems, to model the dynamic systems. We propose strategic coalition consisting of many agents and simulate their emergence in a co-evolutionary learning environment. Also we introduce the concept of confidence for agents in a coalition and show how such confidences help to improve the generalization ability of the whole coalition. Experimental results are presented to demonstrate that co-evolutionary learning with coalitions and confidence allows better performing strategies that generalize well.

• Journal of Internet Computing and Services
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• v.7 no.2
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• pp.137-149
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• 2006

In this paper, we suggest a message-based communication protocol and a dynamic role assignment mechanism for efficient cooperation and teamwork of agents in computer game environments. This role assignment mechanism is a new one different from both existing static and dynamic mechanisms, in which all decisions related with role assignment are made at once in design phase or execution phase. According to our mechanism, all possible role sets are determined in design phase. Detail decisions regarding which agent takes what role, however, are made in execution phase. This mechanism for role assignment can minimize the negotiation effort in execution phase. Therefore, this mechanism is quite effective especially in real-time multiagent environments. Through experiments, we show the superiority of the new dynamic role assignment mechanism.

• Journal of the Korea Society for Simulation
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• v.19 no.1
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• pp.33-39
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• 2010

As future warfare becomes network-centric, war-game simulators require high interoperability between networked forces and dynamic reconfiguration in accordance with war events. In this paper, we propose an event-driven methodology to develop dynamic war-game simulations. Federates are developed by event-driven web services. The event-driven web services consistently sense war events and response them only if they are interested. By the sense-and-response mechanism and asynchronous event processing, we are able to save simulation time. An Anti-Surface-Warfare simulator is constructed to demonstrate the methodology and suggests that event-driven web services are efficient to model and simulate warfare where numerous events are generated from hardware systems and people dispersed on the network.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.556-559
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• 2007

The notion of linearity is fundamental in science and engineering. Much of system and control theory is based on the analysis of linear system, which does not care whether it is nonlinear and complex. The dynamic programming is one of concerned technology when users are interested in choosing best choice from system operation for nonlinear or dynamic system‘s performance and control problem. In this paper, we will introduce the dynamic programming which is based on discrete system. When the discrete system is constructed with discrete state, transfer between states, and the event to induct transfer, the discrete system can describe the system operation as dynamic situation or symbolically at the logical point of view. We will introduce technologies which are related with controllable of Controlled Markov Chain as shown example of simple game. The dynamic programming will be able to apply to optimal control part which has adaptable performance in the discrete system.

• The Journal of the Korea Contents Association
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• v.12 no.8
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• pp.274-282
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• 2012

This study conducted the following experiment to examine change of physicopsychological function on lumbar stabilization exercise(LSE) and virtual reality game training(Nintendo Wii Sport-NWS) to stroke patients subject for fall prevention. Psychological function was measured by falls efficacy with stroke patients and physical function was measured by static and dynamic balance on comparative analysis of pre, post exercise and each groups in 30 stroke patient subject. Static balance was measured by BBS, FRT, dynamic were measured by TUG, 10m walking test and falls efficacy with stroke patients was measured index of falls efficacy. These result lead us to the conclusion that each group were statistically improved at all physicopsychological test, but BBS, FRT, 10m walking test were more statistically improved at LSE group and falls efficacy with stroke patients were more improved at virtual reality game training group. Consequently, virtual reality game training would be lead to positive increment of physicopsychological function on stroke patient.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.9
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• pp.327-336
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• 2015

Mobile game servers usually execute frequent dynamic memory allocation for generating the buffers that deal with clients requests. It causes to deteriorate the performance of game servers since it increases system workload and memory fragmentation. In this paper, we propose fixed-sized memory pool management method. Memory pool for the proposed method has a sequential memory structure based on circular linked list data structure. It solves memory fragmentation problem and saves time for searching the memory blocks which are required for memory allocation and deallocation. We showed the efficiency of the proposed method by evaluating the performance of dynamic memory allocation, through the proposed method and the memory pool management method based on boost open source library.

• Journal of Korea Game Society
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• v.10 no.2
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• pp.67-80
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• 2010

Investigating the trend of online gamers plays an important role in forecasting, marketing and making policy decision in gaming industry. In this regards, various studies on gamers' trend and characteristics have been conducted. However, these precedent studies show limitation that they're static analysis since they are usually based on the surveys at a certain point. Therefore, this paper aims to identify some implications on forthcoming directions of gaming industry by analyzing dynamic trend of gamers based on the 8 years(from 2002 to 2009) of data from White Paper on Korean Games. Major implications found in this paper are as follows. Negative perception of games increases as the number of gamers increases. Among juveniles, games became a substitute for TV and the amount of time they play games depends on the existence and type of popular games of that time. Also, most item trading is intensively done by a small number of gamers.

• Journal of Communications and Networks
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• v.16 no.6
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• pp.627-638
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• 2014

In this paper, we study the joint price and power allocation in spectrum sharing macro-femtocell networks. The proposed game theoretic framework is based on bi-level Stackelberg game where macro base station (MBS) works as a leader and underlaid femto base stations (FBSs) work as followers. MBS has fixed data rate and imposes interference price on FBSs for maintaining its data rate and earns revenue while FBSs jointly adjust their power for maximizing their data rates and utility functions. Since the interference from FBSs to macro user equipment is kept under a given threshold and FBSs compete against each other for power allocation, there is a need to determine a power allocation strategy which converges to Stackelberg equilibrium. We consider two cases for MBS power allocation, i.e., fixed and dynamic power. MBS can adjust its power in case of dynamic power allocation according to its minimum data rate requirement and number of FBSs willing to share the spectrum. For both cases we consider uniform and non-uniform pricing where MBS charges same price to all FBSs for uniform pricing and different price to each FBS for non-uniform pricing according to its induced interference. We obtain unique closed form solution for each case if the co-interference at FBSs is assumed fixed. And an iterative algorithm which converges rapidly is also proposed to take into account the effect of co-tier interference on interference price and power allocation strategy. The results are explained with numerical simulation examples which validate the effectiveness of our proposed solutions.

• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.4
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• pp.71-80
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• 1997

In this paper, we consider with a market pioneering game among symmetric firms in highly competitive situation. To describe the puzzling situation of timing competition, we construct a dynamic game model and explore the equilibrium solution. As a result, we find a subgame perfect mixed strategy Nash equilibrium conceptually defined by 't$_{0}$ + .elsilon. equilibrium'. Our major finding s include : i) market entry will be occurred in sequential manner even though the condition of each firm is symmetric ii) the optimal timing of market pioneering will be advanced until almost all of the monopolist's profit is dissipated, iii) as the market position of the pioneer is stronger, the timings of the pioneer and the follower are separated, iv) and as the slope of the profit flow is steeper, the entry timing of the two players will be pooled together.

• Korean System Dynamics Review
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• v.1 no.2
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• pp.61-89
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• 2000

The purpose of this study is first, to find out what factors affect the cooperation and trust within the functions in the policy implementation network and in what mechanism these factors interact, second to investigate the whys to manage trust and cooperation successfully in the dynamic situation such as the network setting. For these purpose, this study reviews the concept and characteristics of policy implementation organizations, second, extracts the various factors affecting trust and cooperation in the network situation, third applies and analyzes the relationship among factors to system dynamics model based on the game theory. The results of this study could be summarized as follows: It was found that the utility change within the participants by persuasion ＆ mutual understanding and change of rule would be leading to success in policy implementation network. Also bureaucratic management such as power enforcement does not have any good impact in the managing network. In this study, system simulation method tried to analyze the hypothesis. Quantitative and case analyses were not accompanied and analysis was limited to two-person game theory. So there is some doubt this results could be generalized to actual situation which is N-person game.