• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권2호
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• pp.217-222
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• 2004

A person does communication between each other using language. But, In the case of disabled person, cannot communicate own idea to use writing and gesture. We embodied communication system using the EEG so that disabled person can do communication. After feature extraction of the EEG included facial muscle signals, it is converted the facial muscle into control signal, and then did so that can select character and communicate idea.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권3호
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• pp.256-265
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• 2017

In this paper, an ascheme is proposed for multiuser underwater acoustic communication by using the multi-chirp rate signals. It differs from the well known TDMA (Time Division Multiple Access), FDMA (Frequency Division Multiple Access) or CDMA (Code Division Multiple Access), by assigning each users with different chirp-rate carriers instead of the time, frequency or PN code. Multi-chirp rate signals can be separated from each other by FrFT (Fractional Fourier Transform), which can be regarded as the chirp-based decomposing, and superior to the match filter in the underwater acoustic channel. VTRM (Virtual Time Reverse Mirror) is applied into the system to alleviate the ISI caused by the multipatch and make the equalization more simple. Results of computer simulations and pool experiments prove that the proposed multiuser underwater acoustic communication based on the multi-chirp rate exhibit well performance. Outfield experments carrie out in Xiamen Port show that using about 10 kHz bandwidth, four users could communicate at the same time with 425 bps with low BER and can match the UAC application.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.510-513
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• 2005

Due to the asymptotic property, deadbeat control can hardly be applied to the continuous time system control. But some delay element method can deal such a problem. Besides delay element method, well-known digital deadbeat control can be used by the aid of some smoothing elements. In this paper, 2nd order smoothing element is used for the smoothing of the digital deadbeat controller. And this element is argumented to the plant, and so control problem is to control the argumented system digitally. We simulated this control system using Matlab language and finally apply this algorithm to the rotary inverted pendulum system.

• 한국인터넷방송통신학회논문지
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• 제15권2호
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• pp.51-55
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• 2015

본 논문에서는 차량 통신에서 겪을 수 있는 페이딩의 영향을 완화하기위해 협력 통신을 적용하여 다이버시티 이득을 얻을 수 있는 방안을 제안하였다. 사용된 중계기는 버스와 같이 고정된 경로를 주행하는 이동 차량으로 설정하였으며 차량을 사용할 경우 전력 제약을 해결할 수 있다. 또한 도심 지역과 유사한 페이딩 환경에서 모의실험을 진행하기 위해 이중 레일리 페이딩 환경을 적용하였다. 따라서 제안된 기법을 일반적인 차량 통신 네트워크에 적용할 경우, 도심에 위치한 이동형 중계기로 인해 다이버시티 이득을 보장받을 수 있으므로 네트워크의 효율성이 증가한다. 마지막으로, 비트 오류율(Bit Error Rate)을 통해 시스템의 성능을 평가한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권3호
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• pp.1111-1130
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• 2016

Cooperative communications can significantly improve the wireless transmission performance with the help of relay nodes. In cooperative communication networks, relay selection and power allocation are two key issues. In this paper, we propose a relay selection and power allocation scheme RS-PA-PSACO (Relay Selection-Power Allocation-Particle Swarm Ant Colony Optimization) based on PSACO (Particle Swarm Ant Colony Optimization) algorithm. This scheme can effectively reduce the computational complexity and select the optimal relay nodes. As one of the swarm intelligence algorithms, PSACO which combined both PSO (Particle Swarm Optimization) and ACO (Ant Colony Optimization) algorithms is effective to solve non-linear optimization problems through a fast global search at a low cost. The proposed RS-PA-PSACO algorithm can simultaneously obtain the optimal solutions of relay selection and power allocation to minimize the SER (Symbol Error Rate) with a fixed total power constraint both in AF (Amplify and Forward) and DF (Decode and Forward) modes. Simulation results show that the proposed scheme improves the system performance significantly both in reliability and power efficiency at a low complexity.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권3호
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• pp.1212-1228
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• 2016

Secure communication is an important aspect of today's interconnected environments and it can be achieved by the use of cryptographic algorithms and protocols. However, many existing cryptographic mechanisms are tightly integrated into communication protocols. Issues emerge when security vulnerabilities are discovered in cryptographic mechanisms because their replacement would eventually require replacing deployed protocols. The concept of cryptographic agility is the solution to these issues because it allows dynamic switching of cryptographic algorithms and keys prior to and during the communication. Most of today's secure protocols implement cryptographic agility (IPsec, SSL/TLS, SSH), but cryptographic agility mechanisms cannot be used in a standalone manner. In order to deal with the aforementioned limitations, we propose a lightweight cryptographically agile agreement model, which is formally verified. We also present a solution in the Agile Cryptographic Agreement Protocol (ACAP) that can be adapted on various network layers, architectures and devices. The proposed solution is able to provide existing and new communication protocols with secure communication prerequisites in a straightforward way without adding substantial communication overhead. Furthermore, it can be used between previously unknown parties in an opportunistic environment. The proposed model is formally verified, followed by a comprehensive discussion about security considerations. A prototype implementation of the proposed model is demonstrated and evaluated.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.659-665
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• 2003

This paper presents a Train Communication Network simulator (TCNS) that can be used to evaluate the performance of TCN. TCN was accepted as the standard of the protocol for the communication network in trains. We carry out some simulation tests using the TCNS to show practical uses of the simulator. Results of some simulation tests are also reported. This paper presents a Train Communication Network simulator(TCNS) that can be used to evaluate the performance of TCN. TCN was accepted as the standard of the protocol for the communication network in trains. TCN of fieldbus was adopted as international standardization IEC 61375 in 1999. It has been operating on G7 train in korea. This paper developed TCNS(Train Communication Network simulator) as a simulator for performance evaluation. We can verify TCNS for preventing many kinds of occurring problems between the devices in data-communication. This study was developed TCNS as a simulator for the performance evaluation. We analyzed correlation between token, transmission data per paket and transmission speed of bus, through the TCNS, also analyzed result according to error rate of TCN. We carry out some simulation tests using the TCNS to show practical uses of the simulator. Results of some simulation tests are also reported.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.229-232
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• 2005

Many kinds of communication systems will be co-existed in the next generation communication environment. Location management will be one of the most important strategies in the future communication network. Whether the user gets the service in any kind of communication system, it is required to know the location of the user properly and manages this location information efficiently. In this paper, mobile IP and WCDMA systems are considered as next generation communication systems. We improve the performance of communication in heterogeneous networks adjusting the conventional region-based location management strategy in homogeneous network. This strategy can be adjusted dynamically to the communication system on the basis of packet-to-mobility ratio (PMR) in mobile IP system or call-to-mobility ratio (CMR) in WCDMA system, lots of different system parameters, and movement pattern of the user. This can be also based on the performance analysis with considering signaling cost and database access cost.

• Journal of Multimedia Information System
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• 제3권4호
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• pp.135-140
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• 2016

To improve the throughput of Device-to-Device (D2D) communication, we focus on the scenario where D2D pair can reuse multi-channel of cellular communication. However, as sharing same channel with cellular communication can cause interference between D2D communication and cellular communication, a proper interference management is needed. In this paper, we propose interference-based channel allocation to select the channels to be used by D2D communication and a solution from game theory perspective to optimize the D2D communication throughput under multi-channel as well as guarantee the interference from it to cellular network. The simulation results verify the stability of the proposed method.

• Journal of information and communication convergence engineering
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• 제18권1호
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• pp.8-15
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• 2020

Internet-of-Things (IoT) technologies are used everywhere, and communication is one of its core and essential aspect. To solve the networking and communication of small IoT terminals, in this paper, a communication scheme based on low-cost WiFi is proposed, which also has the advantages of good compatibility and low power consumption. At the same time, it has a convenient one-key configuration mode, which reduces the technical requirements for operators. In this study, a communication protocol is designed that mainly aims at up to dozens of domestic IoT terminals, in which the amount of data is not large, data exchange is not high, and network is unstable. According to the alarm data, update data, and equipment or network fault, the protocol can respectively transmit in real time, regularly and repeatedly. This protocol is open and easy to integrate, and after cooperating with tiny encryption algorithm, information can be safely transmitted.