• The Journal of Korean Physical Therapy
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• v.23 no.4
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• pp.37-44
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• 2011

Purpose: The aim of this study was to investigate the effects of an exercise program using a virtual reality game and a gait exercise program using a treadmill on % maximum voluntary isometric contraction (%MVIC) and static and dynamic balancing capabilities. Methods: A total of 26 elderly women were included in the study. 13 women were assigned to an exercise program using a virtual reality game, and 13 to a gait exercise program using a treadmill. The subjects performed the exercise for 40 min per session, three sessions per week, for eight weeks. Results: The %MVIC of the vastus medialis was significantly increased from $28.91{\pm}2.03%$ to $32.98{\pm}2.6%$ in the virtual reality game exercise group (p<0.00). The %MVIC of the vastus lateralis was significantly increased from $27.17{\pm}1.93%$ to $31.50{\pm}2.18%$ (p<0.00) in the gait exercise program group. The whole path length with both feet on the floor and eyes open was significantly decreased from $1570.92{\pm}820.6mm$ to $1343.62{\pm}242.41mm$ (p<0.00). The whole path length with both feet on the floor and eyes closed was significantly decreased from $1819.85{\pm}361.14mm$ to $1581.05{\pm}285.11mm$ (p<0.00). The length of a functional reach was significantly increased from $25.2{\pm}4.23cm$ to $27.68{\pm}4.04cm$ (p<0.00). Conclusion: The exercise program using a virtual reality game is effective for improving the %MVIC and static and dynamic balancing capabilities in elderly women aged 65 years and more.

• Journal of Digital Contents Society
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• v.12 no.4
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• pp.559-565
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• 2011

In this paper, I propose a distributed game server system which has flexibility of enormous game character's processing in MMORPG using block scheme. I proposed game servers in distributed system grouped with zone which charge of each map, and the game servers in this zone divide game map into several unit blocks and process distributing blocks to game servers according to its performance. I proposed distributed game server system using block scheme can add/drop game map to/from easily through block process method in game and communication servers. Therefore, my proposed system can enormous character processing and add user created game map to existed game map easily in the future as well. Also, my scheme increases the system utilization and upgrades system stability by dynamic distribution of game map according to the number of characters and performance of servers.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.3
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• pp.23-40
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• 2014

This paper measures the operational efficiency of domestic online game companies and analyze its trends and patterns by using data envelopment analysis (DEA). DEA is a non-parametric approach to measuring the relative efficiency of decision-making units (DMUs) with multiple inputs and outputs. 14 online game companies are selected as DMUs and three inputs (number of employees, capital and asset) and three outputs (sales, operating profit and net profit) are selected as DEA variables. First, the output-oriented BCC model and super-efficiency model are employed to measure the static operational efficiency of the online game companies from 2003 to 2012. We also conduct the dynamic analysis with DEA window model to capture the trends of their operational efficiency influenced by internal and external environmental changes. The results are expected to provide fruitful implications for strategic decision making of online game companies and policy making for the online game industry.

• The Journal of the Convergence on Culture Technology
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• v.2 no.4
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• pp.49-54
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• 2016

Development of AR/VR has expanded computer games from indoor static contents to outdoor dynamic contents. The syndrome of 'Pokemon Go' which is a representative AR game was born, and Nintendo's stock price shot up a massive 120%. Although some people gained profits, new damages are emerging including illegal intrusion or road accidents because it is a type of game to visit real locations. There are reported about 114 thousand road accidents related to the game. This study aims to examine the trends of AR game in 2016 and analyze damages and positive cases to suggest a method for preventing accidents due to the AR game, and a business model.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.509-516
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• 2011

This paper studies a novel method to find the profit-maximizing Nash Equilibriums in allocating generation quantities with consideration of ramp-rates under competitive market environment. Each GenCo in a market participates in a game to maximize its profit through competitions and play a game with bidding strategies. In order to find the Nash equilibriums it is necessary to search the feasible combinations of GenCos' strategies which satisfy every participant's profit and no one wants various constraints. During the procedure to find Nash equilibriums, the payoff matrix can be simplified as eliminating the dominated strategies. in each time interval. Because of the ramp-rate, generator's physically or technically limits to increase or decrease outputs in its range, it can restrict the number of bidding strategies of each generator at the next stage. So in this paper, we found the Nash Equilibriums for multi-stage generation allocation game considering the ramp-rate limits of generators. In the case studies, we analyzed the generation allocation game for a 12-hour multi-stage and compared it with the results of dynamic economic dispatch. Both of the two cases were considered generator's ramp-rate effects.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.149.5-149
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• 2001

The robot soccer simulation game is a dynamic multi-agent environment. In this paper we suggest a new reinforcement learning approach to each agent´s dynamic positioning in such dynamic environment. Reinforcement learning is the machine learning in which an agent learns from indirect, delayed reward an optimal policy to choose sequences of actions that produce the greatest cumulative reward. Therefore the reinforcement learning is different from supervised learning in the sense that there is no presentation of input-output pairs as training examples. Furthermore, model-free reinforcement learning algorithms like Q-learning do not require defining or learning any models of the surrounding environment. Nevertheless ...

• Journal of Korean Medicine Rehabilitation
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• v.21 no.2
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• pp.227-238
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• 2011

Objectives : This study was to investigate the effects on using Virtual reality exercise program($Wii-Fit^{TM}$) for dynamic balance and walking ability in patients with stroke. Methods : The 22 subjects were randomly selected from the patients of the S hospital who met the study conditions. They were divided into a $Wii-Fit^{TM}$ balance game group of 12 patients and a conventional physical therapy group of 10 patients. The $Wii-Fit^{TM}$ balance game group received $Wii-Fit^{TM}$ balance game group general physiotherapy for 5 days a weeks, 30 minutes a day, for a 4 weeks and the conventional physical therapy group received general physiotherapy for the same period. The subjects were measured and compared for Brunel balance assessment, functional gait assessment, 6 minute walk test, GAITRite system before and after the program. Results : The experimental group tend to improve more than control group in shifting the weight to the affected side(p=0.040) and tap test(p<0.001). The experimental group tend to improve more than control group in FGA(p=0.016). The experimental group improved significantly more than control group in 6MWT(p=0.008). The experimental group improved significantly more than control group in gait speed, cadence, stride length. Conclusions : Virtual Reality program($Wii-Fit^{TM}$) with conventional physical therapy shows the benefits on dynamic balance and gait parameters in patients with stroke.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.10
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• pp.5260-5275
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• 2019

In the process of constructing the traditional offensive and defensive game theory model, these are some shortages for considering the dynamic change of security risk problem. By analysing the critical indicators of the incomplete information game theory model, incomplete information attack and defense game theory model and the mathematical engineering method for solving Bayes-Nash equilibrium, the risk-averse income function for information assets is summarized as the problem of maximising the return of the equilibrium point. To obtain the functional relationship between the optimal strategy combination of the offense and defense and the information asset security probability and risk probability. At the same time, the offensive and defensive examples are used to visually analyse and demonstrate the incomplete information game and the Harsanyi conversion method. First, the incomplete information game and the Harsanyi conversion problem is discussed through the attack and defense examples and using the game tree. Then the strategy expression of incomplete information static game and the engineering mathematics method of Bayes-Nash equilibrium are given. After that, it focuses on the offensive and defensive game problem of unsafe information network based on risk aversion. The problem of attack and defense is obtained by the issue of maximizing utility, and then the Bayes-Nash equilibrium of offense and defense game is carried out around the security risk of assets. Finally, the application model in network security penetration and defense is analyzed by designing a simulation example of attack and defense penetration. The analysis results show that the constructed income function model is feasible and practical.

• Journal of Korea Entertainment Industry Association
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• v.14 no.5
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• pp.49-57
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• 2020

This paper analyzed maximized the tension not by functional restriction but by psychological response inducement to form the tension of the horror game from the point of space time view. In order that, We arranged three major situations inducing the tension in the horror game and prepared space time analysis base. Pure fiction time of game itself is applied on game time excluding the time creating the cut-scene and the game space is organized with various combination of three space types. This analysis result can help horror game design by discovering the relationship between space time structure and tension forming of the horror game. These analysis results allow us to find guidelines for the time and space design of horror games that can be flexibly linked to game events and contexts by controlling the player's dynamic/static tension and temporary/continuous tension.

• Journal of Communications and Networks
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• v.17 no.1
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• pp.75-83
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• 2015

In mobile ad-hoc networks (MANETs), nodes are mobile in nature. Collaboration between mobile nodes is more significant in MANETs, which have as their greatest challenges vulnerabilities to various security attacks and an inability to operate securely while preserving its resources and performing secure routing among nodes. Therefore, it is essential to develop an effective secure routing protocol to protect the nodes from anonymous behaviors. Currently, game theory is a tool that analyzes, formulates and solves selfishness issues. It is seldom applied to detect malicious behavior in networks. It deals, instead, with the strategic and rational behavior of each node. In our study,we used the dynamic Bayesian signaling game to analyze the strategy profile for regular and malicious nodes. This game also revealed the best actions of individual strategies for each node. Perfect Bayesian equilibrium (PBE) provides a prominent solution for signaling games to solve incomplete information by combining strategies and payoff of players that constitute equilibrium. Using PBE strategies of nodes are private information of regular and malicious nodes. Regular nodes should be cooperative during routing and update their payoff, while malicious nodes take sophisticated risks by evaluating their risk of being identified to decide when to decline. This approach minimizes the utility of malicious nodes and it motivates better cooperation between nodes by using the reputation system. Regular nodes monitor continuously to evaluate their neighbors using belief updating systems of the Bayes rule.