• 인터넷정보학회논문지
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• 제18권2호
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• pp.1-11
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• 2017

스마트 디바이스를 이용하여 특정 공간에서 미리 설정된 무선랜에 접속하는 방법은 개방형 방식과 사용자 인증 방식으로 나뉠 수 있다. 개방형 방식은 무선랜 접속을 위한 인증이 없이 접속하는 방법이다. 스마트 디바이스 사용자가 자신이 사용하려는 무선랜에 대한 정보를 SSID(Service Set IDentifier)를 통해 공공 무선랜 표기 형식에 따라 제공받아야 하지만, 모든 개방형 무선랜이 이러한 방식을 수동으로 입력하는 방식에는 무리가 있다. 반면에 사용자 인증 방식은 SSID와 PW(PassWord) 설정을 통해 사용자에게 무선랜 접속을 제공하는 방식이다. 따라서 SSID를 통해 공공 무선랜 표기 형식을 따를 수는 있지만, AP 접속을 위해서는 일일이 사용자가 수동으로 패스워드 입력을 통해 AP에 접속해야만 한다. 따라서 본 논문에서는 사용자 인증방식과 공공 무선랜 표기형식을 iBeacon 메시지 수신을 통해 자동적으로 AP에 접속할 수 있는 방안을 제안한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.233-234
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• 2004

The study for ubiquitous computing infra is proceeding actively, it make possible to use service and access network anywhere, anytime because of wire/wireless communication technology and progress of hardware. Domestically, study for the network mobility support technology which is the key technology for future ubiquitous computing realization have progressed, but that is Insufficient. Especially, there is no study for independent mobility support study about railway wireless network. So, this study propose network mobility management technology for mobile network infra in railway and proper network model in train.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.46-46
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• 2000

A quadruped monitoring robot is introduced. The robot has several features that poses arbitrary position thanks to a 4-wheel hive mechanism, transmits an image and command data via RF wireless communication, and moreover, the imaged date are transferred through a network communication. The robot plays a role in monitoring what is happening around the robot and covers wide range due to a moving camera operated by the 4-wheel mechanism. The robot system can be applied k versatile models based the distinguished techniques introduced in this paper

• 한국정보전자통신기술학회논문지
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• 제11권1호
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• pp.89-94
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• 2018

본 논문에서는 IoT (Internet of Things) 서비스 구현을 위한 스마트센서의 설계 방안을 연구하였다. 지속적인 데이터 수집을 위한 센서의 전원 공급부는 에너지 하베스팅 (Energy Harvesting) 기술을 적용하였으며, 주변 환경으로부터 영향을 줄일 수 있는 압전소자 (piezoelectric transducer)를 선택하여 전원 공급부를 설계하였다. 데이터 전송을 위한 무선통신 인터페이스는 BLE (Bluetooth Low Energy) 기술을 적용하여 설계하였다. BLE는 저전력 단거리 무선 통신에 적합하며, 주요 응용분야인 BLE 비콘 (beacon)은 O2O (Online to Offline) 서비스, 실내 측위 기반의 내비게이터, 도난/미아 방지 서비스에서 모바일 게임 등으로 활용 범위가 확대되고 있다. BLE 무선통신의 짧은 전송 거리를 보완하기 위해 무선 커버리지를 확대할 수 있는 방안을 연구하였으며, 네트워크 구축이 용이하고 무선 커버리지 확대할 수 있는 CATV 망을 활용한 BLE 센서 네트워크 구축 방안을 제안하였다.

• 한국전자통신학회논문지
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• 제9권3호
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• pp.387-392
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• 2014

최근에 전기자동차의 상용화가 머지않은 상황에서 운전자를 위한 다양한 전자적 기능들이 개발되어지고 있다. 특히, 뇌파(EEG)를 통하여 운전자의 상태를 모니터링하면서 졸음방지나 건강상태를 실시간으로 점검하는 기능들이 있다. 자동차 운전자의 뇌파를 의료기관 서버에 전송하여 관련 기능들을 제공할 수 있는데 이때 자동차간 또는 자동차와 노변장치간의 원활한 통신기능이 필수적이다. 따라서 본 논문에서는 도심의 교차로환경에서 원활한 EEG 통신기능을 제공하는 라우팅 프로토콜을 제시하기 위해 AODV, DSR, GRP, OLSR, TORA와 같은 5가지의 라우팅 프로토콜로 운영되는 무선통신망을 각각 설계하고 이를 OPnet 네트워크 시뮬레이션을 통하여 성능을 평가하고 결과를 제시하고자 한다.

• 디지털산업정보학회논문지
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• 제10권4호
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• pp.109-116
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• 2014

In recent, ISM (Industrial Scientific Medical) band that is 2.4GHz band authorized free of charge is being widely used for smart phone, notebook computer, printer and portable multimedia devices. Accordingly, studies have been continuously conducted on the possibility of coexistence among nodes using ISM band. In particular, the interference of IEEE 802.11b based Wi-Fi device using overlapping channel during communication among IEEE 802.15.4 based wireless sensor nodes suitable for low-power, low-speed communication using ISM band causes serious network performance deterioration of wireless sensor networks. This paper examined a method of identifying channel status to avoid interference among wireless communication devices using IEEE 802.11b (Wi-Fi) and other ISM bands during communication among IEEE 802.15.4 based wireless sensor network nodes in ISM band. To identify channels occupied by Wi-Fi traffic, various studies are being conducted that use the RSSI (Received Signal Strength Indicator) value of interference signal obtained through ED (Energy Detection) feature that is one of IEEE 802.15.4 transmitter characteristics. This paper examines an algorithm that identifies the possibility of using more accurate channel by mixing utilization of interference signal and RSSI mean value of interference signal by wireless sensor network nodes. In addition, it verifies such algorithm by using OPNET Network verification simulator.

• 한국철도학회논문집
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• 제9권3호
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• pp.257-263
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• 2006

This paper presents an optimization approach to the configuration of train radio communication network for CBTC. The target specifications of CBTC communication systems are derived from technical requirements for CBTC. The proposed communication system has a ring-topology backbone communication network between stations and a radio network based on IEEE 802.11b wireless tan between trains and wayside devices. The proposed method has been applied to the standardization of the signalling system of urban transits.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권9호
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• pp.2213-2231
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• 2013

Compressed sensing is a novel technology used in the field of wireless communication and sensor networks for channel estimation, signal detection, data gathering, network monitoring, and other applications. It plays a significant role in highly secure, real-time, well organized, and cost-effective data communication in smart-grid (SG) systems, which consist of multi-tier network standards that make it challenging to synchronize in power management communication. In this paper, we present a multi-layer communication model for SG systems and propose compressed-sensing based data transmission at every layer of the SG system to improve data transmission performance. Our approach is to utilize the compressed-sensing procedure at every layer in a controlled manner. Simulation results demonstrate that the proposed monitoring devices need less transmission power than conventional systems. Additionally, secure, reliable, and real-time data transmission is possible with the compressed-sensing technique.

• 한국통신학회논문지
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• 제32권5B호
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• pp.295-303
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• 2007

An algorithm is proposed to seek a local optimal solution of the network utility maximization problem in a wireless mesh network, where the architecture being considered is an infrastructure/backbone wireless mesh network. The objective is to achieve proportional fairness amongst the end-to-end flows in wireless mesh networks. In order to establish the communication constraints of the flow rates in the network utility maximization problem, we have presented necessary and sufficient conditions for the achievability of the flow rates. Since wireless mesh networks are generally considered as a type of ad hoc networks, similarly as in wireless multi-hop network, the network utility maximization problem in wireless mesh network is a nonlinear nonconvex programming problem. Besides, the gateway/bridge functionalities in mesh routers enable the integration of wireless mesh networks with various existing wireless networks. Thus, the rate optimization problem in wireless mesh networks is more complex than in wireless multi-hop networks.

• International Journal of Contents
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• 제7권1호
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• pp.8-13
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• 2011

For energy-efficiency in Wireless Sensor Networks (WSNs), when a sensor node detects events, the sensing period for collecting the detailed information is likely to be short. The lifetime of WSNs decreases because communication modules are used excessively on a specific sensor node. To solve this problem, the TARP decentralized network packets to neighbor nodes. It considered the average data transmission rate as well as the data distribution. However, since the existing scheme did not consider the energy consumption of a node in WSNs, its network lifetime is reduced. In this paper, we propose an energy awareness congestion control scheme based on genetic algorithms in WSNs. The proposed scheme considers the remaining amount of energy and the transmission rate on a single node in fitness evaluation. Since the proposed scheme performs an efficient congestion control, it extends the network lifetime. In order to show the superiority of the proposed scheme, we compare it with the existing scheme through performance evaluation. It is shown that the proposed scheme enhances the data fairness and improves the network lifetime by about 27% on average over the existing scheme.