• Journal of Contemporary Eastern Asia
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• v.21 no.1
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• pp.72-76
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• 2022

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.10
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• pp.941-950
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• 2011

In this paper, we analysis the end-to-end performance of the incremental cooperative communication with relay selection. In the conventional cooperative scheme, the source(S) broadcasts the signal to the relay(R) and the destination(D) at 1st phase, and the R forwards the signal to the D at 2nd phase. Although this scheme can improve performance and provide diversity gain, it suffers from decreasing spectrum efficiency. In order to overcome this problem, the incremental cooperative model can be used. In this paper, we study two incremental cooperative method : the first uses ARQ with threshold SNR and the second uses HARQ with channel coding. we also evaluated performance of the incremental cooperative communication based on the R arrangement by using both methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5B
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• pp.539-548
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• 2011

We propose an efficient cooperative ARQ (Automatic Repeat reQuest) scheme for single-hop and multi-hop underwater acoustic communications, in which cooperative nodes are used to provide more reliable alternative paths for a specific source-to-destination connection. This alternative path has higher channel quality than that of the direct source-destination path. In addition, during a packet-relay through multiple hops, the typical acknowledgement (ACK) signal is replaced with overhearing data packet returned back from the next hop. The usage of overhearing as an ACK improves the system performance. In this paper, we evaluate the proposed scheme by comparing it with a conventional S&W ARQ in terms of throughput efficiency. Computer simulation results show that the proposed cooperative retransmission scheme can significantly improve the throughput by increasing the probability of successful retransmission.

• Journal of the Korea Society for Simulation
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• v.26 no.3
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• pp.35-46
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• 2017

Spare engine plays an important role for securing readiness of military strength during unexpected fault occurrences and field/depot planned maintenances. The purpose of this research is to present an approach towards the optimal number of spare engines/modules for diversity of aircraft types. We first reviewed two representative approaches, METRIC and meta model. We then investigated military aircrafts and categorized them into 5 types with regard to the engine type and number of engines/modules per aircraft. Through rigorous investigation of planned/non-planned maintenance of each type, we drew parameters and variables involved. As known, due to the complexity of the problem, it is impossible to develop a simple mathematical model with a closed form solution. Based on the airbase operation and maintenance logic with parameters/variable drawn, we developed a simulation model using ARENA well representing real field exercises. For the optimal solution, we applied OptQuest. It has shown that the program developed generates reliable results through a set of case examples.

• Journal of Korea Game Society
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• v.19 no.3
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• pp.43-52
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• 2019

Advances in technology are enhancing the player's visual satisfaction in games. Reflexively, narrative satisfaction has not been highlighted. This led to a player's critical view of the absence of original games. Especially in gameplay, quests require repeat and similar content and imperative tasks. It is overlooked that a quest can cause players to produce various meanings and effects. The concept of editing ability to reorganize the designed rules of the player beyond the performance and behavioral rules is conceptualized, and the four types of players that operate the characteristics can see that the player can intensify game play and immerse himself in play saw.

• The Journal of the Korea Contents Association
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• v.19 no.2
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• pp.88-98
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• 2019

As the 2015 revised curriculum is being implemented from 2018, efforts are being made to cultivate scientific literacy among students in the field of science. Scientific experiments help students to develop their interest in Science and their scientific attitudes. Learning through experimentation rather than learning scientific facts increases learners' understanding, and can be remembered longer. Therefore, experiments in Science subject are very important. However, in middle schools, scientific experiments are not performed due to the lack of time, budget and experimental material. In this research, we analyze middle school science textbooks, conduct questionnaires for students of science pre-service teachers, select the most important science experiments, and develop a mobile App to simulate and experience scientific experiments with the App. The proposed App is developed in a game format using quest-based learning methods to gain learning enhancement. It is also made using Unity. In this paper, after developing the app, we propose the direction of STEAM contents development through analyzing the difference from existing apps and the feedback from users.

• Journal of the Korea Society for Simulation
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• v.28 no.1
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• pp.57-65
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• 2019

Air refueling is expected to increase the efficiency of the air force operations. This follows from the introduction of air refueling aircraft, which should to increase operational time by increasing the range and duration of fighter jets. Despite the effectiveness of the air refueling air crafts, the astronomical costs of adapting the air tankers call for careful discussions on whether to acquire any air craft and if so, how many. However there is no academic study on the subject to our knowledge. Thus, we use the ABM(Agent Based Modeling) technique to calculate the optimal number of air tankers during patrol operation. We have enhanced the reliability of the simulation by entering the specifications of the current aircraft operated by the Korean Air Force. As an optimization tool for determining the optimal number of counts, we use OptQuest built into the simulation tools and show that the optimal number of air tanker is 4.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.1
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• pp.213-218
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• 2023

In order to use the VR HMD, operation through separate controllers in both hands is required. Methods for text input in VR include a method of selecting virtual keyboard keys on the screen one by one using a controller, a method of inputting through a keyboard that is a resource of a computer by connecting a computer and VR, or a method of inputting through a keyboard that is a resource of a computer by purchasing a wireless keyboard in VR and wireless keyboard connection method. As such, the text input method in current VR equipment causes inconvenience and additional costs to users. For these reasons, most of the VR-related contents are limited to simple functions such as games or viewers, and there is a risk that VR equipment will be recognized as a simple game machine. Therefore, in this study, a multi-input interface using hand tracking provided by the Oculus Quest2 device is designed and partially implemented. Through this, it is expected that various tasks such as document work and business processing as well as games can be conveniently used using VR equipment.

• Science of Emotion and Sensibility
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• v.7 no.3
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• pp.37-50
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• 2004

This study attempted to explore how online game is endowed new meaning and function and changed into totally different product in result by recognition and consuming behavior(game activity) of game users. The subjects of this study are famous Internet based online games called 'Lineage' and 'EverQuest'. These two online games are physically similar games. Both are MMORPG and community-based games. While Lineage became a cyber world as a part of the real world, EverQuest was a game product. This study explored the recognition of garners about game world and different consuming behavior pattern(game activity pattern) in game world made by different recognition of online game. The result from exploring the differences in the recognition of game world showed Lineage garners regarded Lineage world as another living space or a part of real world they can explore and express psychological need and self-identity or self-image and live through diverse activities. But EverQuest garners regarded EverQuest as a product for experience of fantasy world. The result from comparing the game consuming behaviors showed that different recognition of game world made the differences in the game consuming behavior. The results of the present study supported that the recognition of consumers about digital images or content poducts like online game can be different by the value and experience of consumer, and the different recognition make the different consuming behavior of similar or same products. The results supported that the meaning and value of digital images or digital content are endowed by consumers.

• The Journal of the Korea Contents Association
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• v.9 no.9
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• pp.114-124
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• 2009

73 percent of online games in Korea hold perspectives of medieval times in them. So far in history, about a millennium in medieval times is said to be a period of darkness and savagery, but it is newly revived in the digital virtual world. Such phenomenon is paradoxical and meaningful to often bring out 'medieval times' as a theme for online games, which are revealed by up-to-date technologies in present days. This research examines the background of views of medieval times appeared in online games and how they are realized. Medieval fantasy games have appeared because people dream about escaping from pre-modem times and have fantasy about medieval times. Moreover, perspectives of medieval times have enormously influenced background epics, quest stories, creation of characters in a game scenario. The dual structure having coexistence of nature and super naturalness acts an important role to set up the epic for medieval fantasy games. And medieval romance literature, which has a three-step quest narrative of 'targeting - adventure and fight - achievement' is reflected in a quest story of medieval fantasy games. The strict pyramid system represented by feudalism forms a meaningful metaphor for designing characters, and players organize communities for online games through horizontal collective consciousness in such vertical system of history at the same time.