• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.5
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• pp.390-395
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• 2016

In this paper, a sprint race of human and that of humanoid robot are compared. Sprint race is one of the most popular sports games of human. HuroCup organized by FIRA is the most representative sports event of humanoid robots. The rules of the sprint race in HuroCup are explained and the strategy for the sprint race that humanoid robots can play is proposed. A child-sized humanoid robot is designed and developed so that it can play to follow the rules of the sprint race. The algorithm of the game strategy is applied to the robot, and the robot's performance is tested. Eventually, in HuroCup, it is verified that the developed humanoid robot is suitable to perform the sprint race.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.4
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• pp.399-406
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• 2020

In this paper, we propose a time-varying proportional navigation guidance law that determines the proportional navigation gain in real-time according to the operating situation. When intercepting a target, an unidentified evasion strategy causes a loss of optimality. To compensate for this problem, proper proportional navigation gain is derived at every time step by solving an optimal control problem with the inferred evader's strategy. Recently, deep reinforcement learning algorithms are introduced to deal with complex optimal control problem efficiently. We adapt the actor-critic method to build a proportional navigation gain network and the network is trained by the Proximal Policy Optimization(PPO) algorithm to learn an evasion strategy of the target. Numerical experiments show the effectiveness and optimality of the proposed method.

• Journal of Multimedia Information System
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• v.6 no.3
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• pp.131-138
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• 2019

With the rapid evolution of communication technology, it became possible to overcome the spatial and temporal limitations faced by humans to some extent. Furthermore, the quality of personal life was revolutionized with the emergence of the personal communication device commonly known as the smart phone. In terms of defense networks, however, due to restrictions from the military and security perspectives, the use of smart phones has been prohibited and controlled in the army; thus, they are not being used for any defense strategy purposes as yet. Despite the current consideration of smart phones for military communication, due to the difficulties of network configuration and the high cost of the necessary communication devices, the main tools of communication between soldiers are limited to the use of flag, voice or hand signals, which are all very primitive. Although these primitive tools can be very effective in certain cases, they cannot overcome temporal and spatial limitations. Likewise, depending on the level of the communication skills of each individual, communication efficiency can vary significantly. As the term of military service continues to be shortened, however, types of communication of varying efficiency depending on the levels of skills of each individual newly added to the military is not desirable at all. To address this problem, it is essential to prepare an intuitive network configuration that facilitates use by soldiers in a short period of time by easily configuring the strategy network at a low cost while maintaining its security. Therefore, in this article, the author proposes a Zigbee-based local strategic network by using Opnet and performs a simulation accordingly.

• Asia pacific journal of information systems
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• v.20 no.2
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• pp.39-62
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• 2010

As an engineered product, a software package has multiple dimensions that must be designed judiciously to enhance its competitive viability. Functionality, reliability and price are three such common dimensions. However, many software products are sold as bundles of individual components and the competitive impact of bundling has received less attention in the research literature. In this paper, we examine the implications of software vendors using bundling as an element of competitive strategy. A game theoretic model of the actions of an incumbent and a new entrant is developed and the impact on vendor and consumer welfare is analyzed. Numerical experiments with the model show that (i) increasing bundle size is an effective strategy for the incumbent to increase its payoff at the cost of the entrant's payoff and consumer surplus, especially when the entrant's quality is low (ii) in the presence of bundling, the entrant can still increase its own payoff and consumer surplus at the cost of the incumbent's payoff, by increasing product quality up to the level that best segments market demand with the incumbent and (iii) an increase in bundle size by the incumbent, or an increase in quality by the entrant, can both result in an increase of total surplus. Similar results are observed in a related case where the entrant offers free software bundles. Our results provide insights into how software vendors may strategically use bundling and quality as additional product dimensions in order to stay competitive in the market. These results also inform the competing vendors of the impact of bundling related public policy actions on their respective payoffs.

• Journal of the Korean Operations Research and Management Science Society
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• v.34 no.3
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• pp.165-177
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• 2009

The purpose of this study is to investigate the impact of the Internet channel introduction on the channel composed of a monopoly manufacturer and an independent physical retailer. This study also examines what would be the best strategy for the Independent physical retailer to respond to the new internet channel entry. The game theoretic model consists of a monopolist manufacturer selling its product through a channel system including one independent physical store before the entry of an internet store. The audition of the internet store to this channel system results in a mixed channel comprised of two different types of channels. The new internet store is launched by the manufacturer. The results show that an Internet channel entry has the following impacts on the existing channel members. First, the manufacturer's internet channel introduction mitigates the double marginalization problem of the traditional channel. Second, the manufacturer could enhance Its channel power by introducing its own internet channel while it diminishes that of the incumbent independent physical retailer. Third, manufacturer's adding a new internet store leads to a higher demand. Finally, with its own internet direct channel, the manufacturer has an opportunity to practice price discrimination. The manufacture leaves only those with a strong preference for the physical store to be served by the Independent physical store. The results suggest that the independent physical store's best strategy to the entry of the manufacturer's Internet channel is to focus on the consumers who are highly loyal to the physical store while maintaining a high retail price.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.1
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• pp.64-69
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• 2016

In this paper, a marathon of a humanoid robot is introduced, and its strategy is proposed. In order to develop humanoid robots for the purpose of cooperation and symbiosis with humans, the technologies such as increasing operating time and stability or recognizing surrounding environment are more important. One proper research model for the technologies is a human's marathon. In this paper, we introduce the human's marathon, and propose the humanoid robot's marathon. The marathon event of HuroCup has the most similar game rules to the human's marathon. The humanoid robot developed with the proper operating time, stability and ability to recognize the surrounding environment performed the marathon in HuroCup. The robot recognizes a marathon track using a computer vision, and builds the strategies for the race competition. By analyzing the experimental results, the humanoid robot performed in a real competition.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.4748-4765
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• 2016

We consider a virtualized cognitive radio (CR) network, where multiple virtual network operators (VNOs) who own different virtual cognitive base stations (VCBSs) share the same physical CBS (PCBS) which is owned by an infrastructure provider (InP), sharing the spectrum with the primary user (PU). The uplink scenario is considered where the secondary users (SUs) transmit to the VCBSs. The PU is protected by constraining the interference power from the SUs. Such constraint is applied by the InP through pricing the interference. A Stackelberg game is formulated to jointly maximize the revenue of the InP and the individual utilities of the VNOs, and then the Stackelberg equilibrium is investigated. Specifically, the optimal interference price and channel allocation for the VNOs to maximize the revenue of the InP and the optimal power allocation for the SUs to maximize the individual utilities of the VNOs are derived. In addition, a low‐complexity ±‐optimal solution is also proposed for obtaining the interference price and channel allocation for the VNOs. Simulations are provided to verify the proposed strategies. It is shown that the proposed strategies are effective in resource allocation and the ±‐optimal strategy achieves practically the same performance as the optimal strategy can achieve. It is also shown that the InP will not benefit from a large interference power limit, and selecting VNOs with higher unit rate utility gain to share the resources of the InP is beneficial to both the InP and the VNOs.

• The Journal of the Korea Contents Association
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• v.19 no.1
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• pp.266-277
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• 2019

This study is an exploratory study on the factors that affect the types of user's coping strategies in online game harassment situations. A survey(N=416) was conducted to investigate the experiences of harassment in online games, expectations on organizational response, and the frequencies of selecting each type of coping strategy. The result shows that the female users usually experience more harassment than the male users, especially in sexual harassment. Female users often choose gender masking, seeking help, avoidance, and mirroring strategies compared to males, while males choose self-blame. The effects of harassment experiences, expectation on organizational response, and gender on each type of coping strategy were analyzed using the structural equation model(SEM). Sexual harassment experiences significantly affect all types of strategies, and the higher the expectation on organizational response, the more likely users to seek help rather than to select gender masking. These results are expected to serve the basis for establishing harassment-related regulations in online games.

• School Mathematics
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• v.15 no.3
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• pp.619-632
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• 2013

One area where research is especially needed is their elaboration process and how they elaborate their idea as a group in a mathematical board game re-creation project. In this research, this process was named 'Mathematical Elaboration Process'. The purpose of this research is to understand how the gifted children elaborate their idea in a small group, and which idea can be chosen for a new board game when they are exposed to a project for making new mathematical board games using the what-if-not strategy. One of the gifted children's classes was chosen in which there were twenty students, and the class was composed of four groups in an elementary school in Korea. The researcher presented a series of re-creation game projects to them during the course of five weeks. To interpret their process of elaborating, the communication of the gifted students was recorded and transcribed. Students' elaboration processes were constructed through the interaction of both the mathematical route and the non-mathematical route. In the mathematical route, there were three routes; favorable thoughts, unfavorable thoughts and a neutral route. Favorable thoughts was concluded as 'Accepting', unfavorable thoughts resulted in 'Rejecting', and finally, the neutral route lead to a 'non-mathematical route'. Mainly, in a mathematical route, the reason of accepting the rule was mathematical thinking and logical reasons. The gifted children also show four categorized non-mathematical reactions when they re-created a mathematical board game; Inconsistency, Liking, Social Proof and Authority.

• Information Systems Review
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• v.23 no.3
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• pp.159-176
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• 2021

Obviating user churn is a prominent strategy to capitalize on online games, eluding the initial investments required for the development of another. Extant literature has examined factors that may induce user churn, mainly from perspectives of motives to play and game as a virtual society. However, such works largely dismiss the service aspects of online games. Dissatisfaction of user needs constitutes a crucial aspect for user churn, especially with online services where users expect a continuous improvement in service quality via software updates. Hence, we examine the relationship between a game's quality management and its user base. With text mining and survival analysis, we identify complaint factors that act as key predictors of user churn. Additionally, we find that enjoyment-related factors are greater threats to user base than usability-related ones. Furthermore, subsequent quasi-experiment shows that improvements in the complaint factors (i.e., via game patches) curb churn and foster user retention. Our results shed light on the responsive role of developers in retaining the user base of online games. Moreover, we provide practical insights for game operators, i.e., to identify and prioritize more perilous complaint factors in planning successive game patches.