• Journal of Ocean Engineering and Technology
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• v.11 no.4
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• pp.180-188
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• 1997

This paper proposes a new efficient MAC(Media Access Control) protocol to establish the ultrasonic communication network for underwater vehicles, which ensures a certain level of maximum throughput regardless of the propagation delay of ultrasonic and allows fast data transmission through the multiple ultrasonic communication channel. A MAC protocol for underwater communication network that allows 'peer-to-peer' communication between a surface ship and multiple underwater systems is designed, and the proposed control protocol is implemented for its verification.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.3
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• pp.183-187
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• 2008

In this study, proposes development present condition of fishery information communication system and development direction of communication system by fishery environment change.

• Journal of Contemporary Eastern Asia
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• v.20 no.2
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• pp.35-39
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• 2021

This article discusses the importance of investigating risk and crisis communication in the context of Asian digital societies. It introduces the remaining articles in this special issue.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.3
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• pp.215-220
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• 2021

As the role of robots expands, flexible task planning methods are attracting attention from various domains. Many task planning frameworks are introduced to efficiently work in a wide range of areas. In order to work well in a broad region with multiple robots, various communication conditions should be controlled by task planning frameworks. However, few methods are proposed. In this paper, we propose mission planning methods according to the communication status of robots. The proposed method was verified through experiments assuming different communication states with a multi-robot system.

• Current Optics and Photonics
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• v.3 no.5
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• pp.365-373
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• 2019

This paper investigates the performance of a hybrid single input multiple output radio frequency/free-space optics (SIMO-RF/FSO) communication system. Each SIMO-RF link is modeled as an independent and identically distributed (i.i.d.) Rayleigh distribution, while the FSO link follows a generalized $M{\acute{a}}laga$ (M) distribution. Considering the fixed gain amplify-and-forward (AF) relay and misalignment errors, novel expressions for the outage probability (OP), average bit error rate (ABER) and average capacity are derived. Numerical results show that atmospheric turbulence and misalignment errors can seriously impair the system performance, and the hybrid RF/FSO communication system using SIMO-RF links can greatly improve system performance. We also analyze system performance under different types of modulation schemes. Numerical results are verified by Monte Carlo simulations.

• Journal of Korea Multimedia Society
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• v.23 no.7
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• pp.819-829
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• 2020

Underwater communication is necessarily useful for various application domains such as saving of human lives from underwater disasters, marine resource exploration, underwater military fields, underwater environment or ecosystem monitoring, fish farm monitoring and management, etc. Even though the acoustic wave has been the main underwater communication media until now, several media such as optical waves, VLF/ELF waves, magnetic fields, and infrared rays also began to be treated as possible media for underwater communication. If these underwater communicate-possible media are used mixing together, the underwater communication can be much more reliable and efficient through complementing the disadvantages of each communication media with advantages of other communication media. In fact, mixing and using multi-media for underwater communication requires the data flow control in the connection process of different media due to their communication speed gaps and bandwidth differences, and, specially, in the flow control, the appropriate message fragmentation technique is required inevitably. For this reason, this paper presents a fragmentation framework and technique necessary to the flow control in the underwater multi-media communication. In addition, through its implementation and experiments, this paper shows the feasibility on the realization of the multi-media based underwater communication.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9B
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• pp.1108-1116
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• 2011

The visible light communication system that transmits data by controlling light emission of LED and receives data through photo detecter is considered as one of the strong candidates of the next generation wireless communication systems. The visible light communication provides both lighting and wireless communication wherever the LED lamps are installed. Due to the feature of visible light communication system, the communication is possible within the area that LED light reaches, and the communication quality depends on the light intensity received at the receiver. In this paper, we analyze the effects of LED panel position and lighting angel on communication channel quality in visible light communication systems. Through computer simulations, we prove that position of LED panel and light angle have a great impact on illuminance and SNR of the visible light communication systems.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.31 no.4
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• pp.5-27
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• 2020

This study, as primary research that examines the communication characteristics of the library and the perception of librarians in order to make public libraries a communication space, surveyed the perception of librarians in public libraries and made an attempt to devise activation measures for the communication spaces of the library. As a result, the communication characteristics of the library were derived to be locality, community spirit, and interactivity. In addition, the perception survey found that librarians have positive remarks about the communication spaces of the library. As it shows a high degree of awareness, the library should focus on ways to revitalize communication. First, the direction of communication must be set in order to fulfill library's new role in communication and exchange. Second, it is desirable for the library to free itself from being a quiet space and recreate it as a space for communication. Third, the library needs to exchange and connect with organizations, groups, and gatherings of the community. Fourth, it seems necessary for the library to provide support for the users' independent and voluntary communication and operation of the community.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.3
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• pp.143-152
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• 2008

This thesis is what accident in sea have been produced as lost themselves life and property about 600~700times at every years. Therefore this was induced to experiment on a national basis that the role of communication of ship is to move from lose themselves life and property.

• Journal of Information Processing Systems
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• v.16 no.6
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• pp.1231-1237
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• 2020

In recent years, future information and communication technology (ICT) has influenced and changed our lives. Without various ICT-based applications, we would have difficulty in securely storing, efficiently processing, and conveniently communicating information. In the future, ICT will play a very important role in the convergence of computing, communication, and all other computational sciences and application. ICT will also influence various fields including communication, science, engineering, industry, business, law, politics, culture, and medicine. In this paper, we investigate the latest algorithms, processes, and services in future fields.