• Journal of Communications and Networks
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• v.18 no.4
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• pp.658-669
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• 2016

The tremendous increase in mobile data traffic coupled with fierce competition in wireless industry brings about spectrum scarcity and bandwidth fragmentation. This inevitably results in asymmetric-valued long term evolution (LTE) spectrum allocation that stems from different timing for twice improvement in capacity between competing operators, given spectrum allocations today. This motivates us to study the economic effects of asymmetric-valued LTE spectrum allocation. In this paper, we formulate the interactions between operators and users as a hierarchical dynamic game framework, where two spiteful operators simultaneously make spectrum acquisition decisions in the upper-level first-price sealed-bid auction game, and dynamic pricing decisions in the lower-level differential game, taking into account user subscription dynamics. Using backward induction, we derive the equilibrium of the entire game under mild conditions. Through analytical and numerical results, we verify our studies by comparing the latest result of LTE spectrum auction in South Korea, which serves as the benchmark of asymmetric-valued LTE spectrum auction designs.

• Journal of Korea Game Society
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• v.20 no.2
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• pp.123-138
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• 2020

The purpose of this study is to examine the probabilities and expenditures of game users' loot box purchases and to verify if there are differential effects on adults and teenagers. Results show that the purchasing probability of teenagers was significantly lower than that of adults, and the amount was also low or not significant. In addition, loot box purchasing has a positive correlation with the total expenditure on games, but teenage buyers have a lower game spending than adults do. This suggests the possibility that loot boxes are considered as cost-saving products for teenage gamers.

• Journal of the Korean Operations Research and Management Science Society
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• v.14 no.2
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• pp.97-104
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• 1989

This paper extends the existence proofs of a Nash equilibrium to a more general class of differentila game models with constraints on the control spaces. With the assumptions of continuity, convexity, and compactness, the existence is proved using Kakutani Theorem and via a path-following approach. Furthermore, the proof for a period-by-period optimization of multi-period problems provides an insight to a numerical solution algorithm to differential game models with constraints.

• Child Studies in Asia-Pacific Contexts
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• v.5 no.2
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• pp.63-81
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• 2015

The present study examined electrical brain activations in participants playing three different video games. Forty-five adolescents between the ages of 13-17 (M=14.3 years, SD=1.5) were randomly assigned to play either a violent game, non-violent game, or brain training game. Electroencephalography (EEG) was recorded during video game play. Following game play, participants completed a questionnaire measuring prosocial personality. Results show an association between prosocial personality factors and differential patterns of brain activation in game groups. Adolescents with higher empathy playing the brain training game were positively correlated with frontal asymmetry scores, while empathy scores for those in non-violent and violent game groups were negatively linked to frontal asymmetric activation scores. Those with higher scores in helpfulness in the non-violent game group showed a positive association to left hemisphere activation. Implications behind these findings are discussed in the manuscript.

• International Journal of Aeronautical and Space Sciences
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• v.11 no.2
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• pp.110-117
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• 2010

We propose guidance laws based on a pursuit-evasion game. The game solutions are obtained from a pursuit-evasion game solver developed by the authors. We introduce a direct method to solve planar pursuit-evasion games with control variable constraints in which the game solution is sought by iteration of the update and correction steps. The initial value of the game solution is used for guidance of the evader and the pursuer, and then the pursuit-evasion game is solved again at the next time step. In this respect, the proposed guidance laws are similar to the approach of model predictive control. The proposed guidance method is compared to proportional navigation guidance for a pursuit-evasion scenario in which the evader always tries to maximize the capture time. The capture sets of the two guidance methods are demonstrated.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.10
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• pp.861-866
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• 2013

This paper presents the development of a racing game by controlling multiple smartphones based on ad hoc communication. The proposed racing game by the smartphone-based control interface does not require any specific game console or remote controller. Thus, any multiple users who have smartphones are able to play the game in a monitor at the same time. In addition, the developed game is applicable to actual mobile robots in cases where the positions of all robots are measured, since its game unit is a mobile robot model with a differential drive. An experimental result shows that the racing game in a PC can be realized by the proposed communication interface through four iPhones based on acceleration sensors.

• Proceedings of the Korea Contents Association Conference
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• 2014.06a
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• pp.17-18
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• 2014

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1988.10a
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• pp.3-3
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• 1988

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.4
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• pp.1-9
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• 2013

We propose a heuristic algorithm for war-game model that is appropriate for warfare in which the maneuver of the attacker is relatively certain. Our model is based on a multi-weapon extention of the Lanchester's square law. However, instead of dealing with the differential equations, we use a multi-period linear approximation which not only facilitates a solution method but also reflects discrete natures of warfare. Then our game model turns out to be a continuous game known to have an ${\varepsilon}$-Nash equilibrium for all ${\varepsilon}{\geq}0$. Therefore, our model approximates an optimal warfare strategies for both players as well as an efficient reinforcement of area defense system that guarantees a peaceful equilibrium. Finally, we report the performance of a practical best-response type heuristic for finding an ${\varepsilon}$-Nash equilibrium for a real-scale problem.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.213-215
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• 1995

This paper is concerned with a coplanar pursuit-evasion game of one inertial evader and two identical noninertial pursuers. The terminal time is fired and the payoff is the distance between the evader and the nearest pursuer when tile game is terminated. The value functions and the strategies is constructed for all the game surface. To get a value function, we use the generalization of the Bellman-Isaacs fundamental equation.