• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.11
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• pp.771-778
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• 2014

We propose Femto-cell power control scheme in HeNet with Game Theory. The Femto-cell which provide high quality with low power is issued by many benefits, however there is a bunch of interferences when many Femto-cells use overlapped bandwidth with Macro-cell. We defined base station of cellular networks and mobile users as players of Game Theory, and configured interference effect among each other as power utility function. Futhermore, we showed enhanced overall system performance, lower power usage and interference decrease by using optimal power.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1440-1442
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• 2016

As long term evolution (LTE) is the most widely deployed broadband communication technology so far, efforts are being made to develop LTE-based mission critical public safety (PS) communication systems. In this paper, we propose a device-to-device (D2D) discovery-based radio resource acquisition scheme to support the LTE D2D communication to PS systems and the realization of resource forwarding for user equipments in emergency area.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1374-1379
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• 2016

In almost all schemes of cooperative cognitive radio networks (CCRN), the users transmit and receive signals in half-duplex mode. In this paper, a design of CCRN adopting the full-duplex (FD) technique is addressed. In order to enable FD communication among users in the CCRN, simultaneous transmitting and receiving antennas are employed for the secondary users. Preliminary results from analysis and numerical evaluation indicate that the proposed FD multiple-input-multiple-output CCRN framework can provide a performance gain over the conventional CCRN frameworks.

• Journal of the Korean Society of Systems Engineering
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• v.13 no.2
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• pp.9-17
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• 2017

Concept development of a real-time Field Programmable Gate Array (FPGA)-based switched Ethernet data communication network for the Man-Machine Interface System (MMIS) is presented in this paper. The proposed design discussed in this research is based on the systems engineering (SE) approach. The design methodology is effectively developed by defining the concept development stage of the life-cycle model consisting of three successive phases, which are developed and discussed: needs analysis; concept exploration; and concept definition. This life-cycle model is used to develop an FPGA-based time-triggered Ethernet (TTE) switched data communication network for the non-safety division of MMIS system to provide real-time data transfer from the safety control systems to the non-safety division of MMIS and between the non-safety systems including control, monitoring, and information display systems. The original IEEE standard 802.3 Ethernet networks were not typically designed or implemented for providing real-time data transmission, however implementing a network that provides both real-time and on-demand data transmission is achievable using the real-time Ethernet technology. To develop the design effectively, context diagrams are implied. Conformance to the stakeholders needs, system requirements, and relevant codes and standards together with utilizing the TTE technology are used to analyze, synthesize, and develop the MMIS non-safety data communication network of the APR1400 nuclear power plant.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.8 no.1
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• pp.82-86
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• 2008

The article presents ARTMAP and Fuzzy BK-Product approach underwater obstacle avoidance for the Autonomous underwater Vehicles (AUV). The AUV moves an unstructured area of underwater and could be met with obstacles in its way. The AUVs are equipped with complex sensorial systems like camera, aquatic sonar system, and transducers. A Neural integrated Fuzzy BK-Product controller, which integrates Fuzzy logic representation of the human thinking procedure with the learning capabilities of neural-networks (ARTMAP), is developed for obstacle avoidance in the case of unstructured areas. In this paper, ARTMAP-Fuzzy BK-Product controller architecture comprises of two distinct elements, are 1) Fuzzy Logic Membership Function and 2) Feed-Forward ART component. Feed-Forward ART component is used to understanding the unstructured underwater environment and Fuzzy BK-Product interpolates the Fuzzy rule set and after the defuzzyfication, the output is used to take the decision for safety direction to go for avoiding the obstacle collision with the AUV. An on-line reinforcement learning method is introduced which adapts the performance of the fuzzy units continuously to any changes in the environment and make decision for the optimal path from source to destination.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.3
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• pp.387-392
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• 2014

Now a days, there are various application functions to transmit from vehicles to the Internet and vice versa. And the communication can be operated through a roadside infrastructure including with possible use of routing protocols. Specifically, autonomous vehicles for remote driving and monitoring requires transmitting of high depth of multimedia such as video. Especially in a populated urban area, an efficient network is vital because of handling a great amount of the data. Therefore, in this paper, efficient network topology for a crossroad in urban area is suggested by performance evaluation of vehicular networks using a wireless LAN and a routing protocol. For the performance evaluation, various vehicular network topologies are designed and simulated in OPNet simulator.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.4
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• pp.993-999
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• 2011

In WSN, at the initial stage, sensor nodes are randomly deployed over the region of interest, and self-configure the clustered networks by grouping a bunch of sensor nodes and selecting a cluster header among them. Specially, in WSN environment, in which the administrator's intervention is restricted, the self-configuration capability is essential to establish a power-conservative WSN which provides broad sensing coverage and communication coverage. In this paper, we propose a communication coverage-aware cluster head election algorithm for Herearchical WSNs which consists of communication coverage-aware of the Base station is the cluster head node is elected and a clustering.

• Journal of information and communication convergence engineering
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• v.8 no.1
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• pp.40-44
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• 2010

opportunistic spectrum access (OSA) allows unlicensed users to share licensed spectrum in space and time with no or little interference to primary users, with bring new research challenges in MAC design. We propose a cognitive MAC protocol using statistical channel information and selecting appropriate idle channel for transmission. The protocol based on the CSMA/CA, exploits statistics of spectrum usage for decision making on channel access. Idle channel availability, spectrum hole sufficiency and available channel condition will be included in algorithm statistical information. The model include the control channel and data channel, the transmitter negotiates with receiver on transmission parameters through control channel, statistical decision results (successful rate of transmission) from exchanged transmission parameters of control channel should pass the threshold and decide the data transmission with spectrum hole on data channel. A dynamical sensing range as a important parameter introduced to maintain the our protocol performance. The proposed protocol's simulation will show that proposed protocol does improve the throughput performance via traditional opportunistic spectrum access MAC protocol.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.308-310
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• 2012

최근 무선 센서 네트워크 환경에서 대용량 멀티미디어 데이터에 대한 요구가 증가하면서 통신 대역폭 및 한정적인 에너지의 한계를 극복하기 위한 대안으로 데이터 분할 및 다중 경로 기법들이 제안되었다. 기존 기법들은 데이터 전송 시에 발생하는 부하의 분산을 통해 네트워크의 성능을 향상시킬 수 있다는 것을 증명하였지만, 데이터의 효율적인 분할과 악의적인 공격에 의한 보안성 문제에 대해서 고려하지 않았다. 이러한 문제점을 해결하기 위해 본 논문에서는 비트평면 분할 기반의 보안성 있는 비-중첩 다중경로 라우팅 기법을 제안한다. 제안하는 기법은 멀티미디어 데이터를 비트평면 단위로 분할하여 다중 경로로 전송함으로써 기존의 키 기반의 암호화 기법을 사용하지 않고도 전체 네트워크에 대한 보안성을 향상 시켰다. 또한 경로 상 노드들의 잔여 에너지를 고려하여 데이터 전송을 수행함으로써 전체 네트워크의 에너지 효율성을 향상시켰다. 성능평가 결과, 제안하는 기법은 기존 기법에 비해 노드의 생존율이 평균 50% 이상 향상되었고, 데이터가 노출되더라도 해당 패킷을 가지고 본래 이미지를 복구하는 것이 불가능하기 때문에 높은 보안성을 제공한다.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.199-201
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• 2012

무선 멀티미디어 센서 네트워크를 활용하기 위한 응용에서는 대용량 멀티미디어 데이터 저장 및 처리 기술, 데이터 전송 기술 등과 같은 다양한 기반 기술들이 요구된다. 특히, 응용을 실제 환경에 적용하기 위해서는 대용량 데이터에 대한 데이터 보안 기술은 필수적이다. 본 논문은 여러 해킹 기술 중 하나인 스니핑 공격으로부터 원천적인 방어를 위해, 데이터 전송 경로를 위험 요소로부터 물리적으로 회피시키기 위한 다중 경로 라우팅 기법을 제안한다. 제안하는 기법은 위험 요소의 감지 반경과 움직임을 토대로 위험 요소의 인근에 위치한 센서 노드에 준비태세 단계를 설정한다. 이를 기반으로 데이터의 우선 순위를 설정하여 데이터 라우팅 과정에서 준비태세 단계와 데이터의 우선 순위를 고려하여 우선순위에 맞는 안전한 경로를 통해 위험요소 우회 다중 경로 라우팅을 수행한다. 시뮬레이션을 통해 제안하는 기법의 구현 가능성을 제시하였으며, 준비태세를 기반으로 효과적인 위험요소 우회 다중 경로 라우팅을 보였다.