• Journal of Advanced Marine Engineering and Technology
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• v.28 no.8
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• pp.1291-1298
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• 2004

In development of monitoring and control systems, one of the most important points is to consider a redundancy so that the system can be operated normally although hardware faults are partly occurred. The purpose of this paper is to introduce a monitoring and control system with a redundancy function for I/O servers and communication networks. I/O servers composed with an active server and a standby server. Each server also has 3 communication ports, 2 ports of them were connected to field units and the other 1 port was connected to the other server. Field units have to be constructed to 2 communication ports connected I/O servers through communication lines. Also, server communication module was implemented for analyzing and handling fault elements. and was submodularized for linking easily with a monitoring and control module. An experiment with 2 servers and 2 field units was constructed to demonstrate its effectiveness.

• Journal of Korea Multimedia Society
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• v.17 no.12
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• pp.1473-1483
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• 2014

A public restroom is different from a household toilet in terms of location and a large number of sharing users. In addition, public restroom is usually messy and filthy. Recently, public toilet tends to be clearly managed than before, but it still has hygienic and clear problems. In this paper, we propose a machine-to-machine (M2M)-based public restroom management system to solve these problems, in which the system with a wireless communication device sends the status information of the toilet, such as blockage or trouble detected by a sensor, to the manager of the restroom at a remote location. In particular, we have developed a prototype management system for public restroom taking into account several system requirements, and verified the basic operations and performance of the management system. With the application of the system to public facilities, it will furnish users with more pleasant environments by restroom administrators who can respond effectively to the troubled toilet.

• Journal of Industrial Convergence
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• v.22 no.2
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• pp.55-62
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• 2024

Visible light communication, which transmits information using visible light, has advantages such as ultra-high speed, ultra-delay, and ultra-connectivity, so research is being conducted as a way to complement 6G communication. In this paper, a study was conducted to overcome the performance degradation caused by the RGB mixing ratio in visible light communication. In a visible light communication system using LED lighting, the role of lighting is an important function, and when used for communication, the performance difference according to the RGB mixing ratio inevitably occurs. In particular, if the intensity of light is below a certain standard, the problem of deteriorating the performance of the entire system occurs. In this study, when a certain performance or less occurs in the communication system caused by the difference in the mixing ratio among the three RGB channels, the remaining two signals except the LED with the best performance are transmitted to STBC (Space-Time Block Coding) to ensure the quality of communication. A computer simulation was performed to verify the performance of the proposed system, and it can be seen that the performance of the proposed system is improved compared to the existing system.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.41.6-41
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• 2002

In this paper, we present a remote control strategy for vehicles moving in an intelligent Vehicle Highway System(IVHS). We study a method for optimal off-line scheduling of a limited communication channel that is used for lead vehicle control in a platoon. The deviated distance from the desired trajectory is used for defining a cost functional that measures the performance of the system with communication constraints in relation to the desired system without communication constraints. The optimal communication sequence is obtained by simulations.

• 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 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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.4
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• pp.46-52
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• 2022

In the existing wired communication network, wired communication is frequently interrupted by lightning, which accompanies rain, and remote management cannot be performed when it is actually necessary. In the case of communication interruption, field data stored in the database are lost, and data at an important point in time may go missing; this causes a decrease in the reliability of the stored data. Therefore, in this study, wireless communication using the Internet of Things (IoT) communication network of the 4^th industrial technology is installed in the prototype to reduce wired communication construction costs, prevent resource waste and environmental damage due to communication facility construction, and prepare for communication loss.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.747-754
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• 2017

Chaos-based secure communication systems are alternative of standard spread-spectrum systems that enable spreading the spectrum of the information signals and encrypting information signals with simple and inexpensive chaotic circuitry. In secure communication area, like Lorenz, Chua, Rossler, Duffing etc, classical systems are widely used. Malasoma chaotic system is topologically simple but their dynamical behaviors are non-linear synchronization and secure communication applications has not seen in paper. This paper aims for introducing a new chaotic system which is able to use as alternative to classical chaotic systems into secure communication fields. In addition, this new model simulates a synchronous communication system using P-C (Pecora-Carroll) method by verifying security with chaos signal through simulation. Modelling, synchronization and secure communication applications of Malasoma are realized respectively in MATLAB-Simulink environment. Retrieved results show that this novel chaotic system is able to use in secure communication fields.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.79-85
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• 2016

Recently, visible light communication(VLC) is being actively researched as green wireless communication services are drawing attention. Currently, VLC mostly uses LED for transmission and PD(Photo Diode) for receiving. However, this kind of system has limited applications. Therefore, we design and propose in this paper, a LED-to-LED two way VLC system that doesn't use PD(Photo Diode). This system has the following features and contributions. First, this system uses just LED at both transmitter and receiver with analog switch, Second, this system support both one-way communication and two way communication together. One way communication can support multi-hop communication. The performance evaluation of the proposed system is conducted at a place with standard light. We test the success or failure of one way communication by changing distance and baud rate while test the success and failure of two way communication by changing distance. We expect that the proposed LED-to-LED system in this paper can be applied for various application fields.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.6 no.1
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• pp.51-56
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• 2013

In this paper, we had design the module of the LED-based media transmission mechanics visible light communication system. To implement the media transmission system through visible light communication transmitter, receiver module the using high brightness, we proposed visible light communication system to implement communication distance of up to a maximum transmitter-receiver distance using a variable PD sensor to the receiver and 1~12 the LED light-emitting device to the transmitter. It was increased efficiency of approximately 20% by measuring the performance during lens wearing or not wearing on the LED module to improve the efficiency of the media transmission system.