• International Journal of Naval Architecture and Ocean Engineering
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• 제2권3호
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• pp.171-176
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• 2010

This paper proposes the application of sensor technology to assemble ship blocks efficiently. A sensor-based monitoring system is designed and implemented to improve shipbuilding productivity by reducing the labor cost for the adjustment of adequate positioning between ship blocks during pre-erection or erection stage. For the real-time remote monitoring of relative distances between two ship blocks, sensor nodes are applied to measure the distances between corresponding target points on the blocks. Highly precise positioning data can be transferred to a monitoring server via wireless network, and analyzed to support the decision making which needs to determine the next construction process; further adjustment or seam welding between the ship blocks. The developed system is expected to put to practical use, and increase the productivity during ship blocks assembly.

• Journal of Electrical Engineering and Technology
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• 제4권1호
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• pp.131-134
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• 2009

We have proposed an indoor positioning system for moving objects and/for the blind or visually impaired to play various sports. [ for a blind or visually impaired playing various sports.] This system consists of a wireless heart rate monitor, wireless sensor network and / 4 ultrasound satellites [ configuration with four ultrasound satellite modules) at the corners of the room. This system provides / the real-time measurement of the location and heart rate of the person in the room[ non-invasive measurement method of the heart rate and the location of a person in real time ], and will help the [a] blind or visually impaired enjoy sports more easily.

• 한국산업융합학회 논문집
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• 제10권2호
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• pp.105-113
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• 2007

Accurate and low-cost sensor localization is a critical requirement for the deployment of wireless sensor networks in a wide variety of application. Sensor position is used for its data to be meaningful and for energy efficient data routing algorithm especially geographic routing. The previous works for sensor localization utilize global positioning system(GPS) or estimate unknown-location nodes position with help of some small reference nodes which know their position previously. However, the traditional localization techniques are not well suited in the senor network for the cost of sensors is too high. In this paper, we propose the sensor localization method with a mobile robot, which knows its position, moves through the sensing field along pre-scheduled path and gives position information to the unknown-location nodes through wireless channel to estimate their position. We suggest using the sensor position estimation method and an efficient mobility path model. To validate our method, we carried out a computer simulation, and observed that our technique achieved sensor localization more accurately and efficiently than the conventional one.

• 한국정보통신학회논문지
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• 제12권2호
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• pp.385-390
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• 2008

무선 센서 노드의 거대한 네트워크를 통해서 환경을 감시하려는 연구가 매우 활발히 진행되고 있다. 무선 센서 노드들은 매우 작고, 가볍고, 비용이 저렴하여야 한다. 네트워크 안에서 주어진 노드가 어디에 물리적으로 놓여져 있는지를 알아내는 위치인식은 무선 센서 네트워크에서 아주 중요한 문제들 중의 하나이다. 그러나 노드의 크기 제한, 비용 등의 제약조건에 의해 GPS사용을 배제한 간단한 위치인식 방법이 요구된다. 본 논문에서는 RF 통신을 사용하는 건물 밖의 환경에서 위치인식을 위한 아주 단순한 접속성를 이용한 방법을 제안한다. 제안된 방법은 모의실험을 통해 그 효용성을 입증한다.

• 한국항행학회논문지
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• 제10권3호
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• pp.268-275
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• 2006

가정과 사무실 정보 응용 및 서비스의 급격한 확산은 광대역 근거리 멀티미디어 통신을 가능하게 하는 새로운 무선 기술을 필요로 하고 있다. 고품질 미디어와 고속의 무선 연결을 위한 요구에 의하여 IEEE 표준화 그룹은 WPAN을 위한 고속 물리 계층을 고려하고 있다. 협대역의 펄스 전송을 기반으로 하는 UWB 다중 접속 기술은 고속의 서비스 제공, 낮은 전력 소모, 정확한 측위를 제공할 수 있는 응용 중의 하나이다. 본 논문에서는 전력 제어된 UWB 디바이스로 구성된 무선 센서 네트워크에서 페이딩 환경에 대한 UWB의 BER 성능을 평가하기 위한 방법론을 제시한다. 얻어진 결과는 주어진 네트워크 구조에 따른 성능 분석을 위하여 사용될 수 있으며 UWB 홈 센서 네트워크를 위한 유용한 디자인 아이디어를 제공할 수 있다.

• 한국통신학회논문지
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• 제34권12A호
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• pp.982-990
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• 2009

IEEE 802.15.4 무선 센서 네트워크는 물리적 또는 환경적 조건을 모니터링하고 수집 하기 위해 센서를 사용하는 독자적인 디바이스로 구성된 무선 네트워크 이다. 최근 센서기술과 정보통신 인프라의 발전으로 환경 모니터링 기술의 하나인 위치추적 기술에 대한 관심이 증가되고 있다. 센서네트워크에서의 일반적인 수신신호 세기 RSSI(Received Signal Strength Indication)를 활용한 위치인식 시스템은 장애물이나 RF의 전파지연 및 멀티패스에 의해 정확한 위치 추적이 어렵다. 따라서 본 논문에서는 RSSI 기반의 위치 추적 시스템이 가지고 있는 이러한 문제를 해결하기 위해 Gaussian Filter algorithm을 적용하여 위치 인식 성능을 개선한다. 이에 RSSI 값에 따른 전파 감쇠 특성을 논의한 후, 노드마다 개별 RSSI 값에 따른 확률적 거리 테이블을 작성한 후 생성된 모델을 통해, 센서 노드로부터 추출된 데이터를 본 논문에서 제안한 Gaussian Filter Algorithm을 적용하여 오차개선을 하였다.

• 제어로봇시스템학회논문지
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• 제10권6호
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• pp.566-573
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• 2004

This paper describes the ubiquitous home network (uHome-net) testbed and LonRF intelligent devices based on LonWorks technology. These devices consist of Neuron Chip, RF transceiver, sensor, and other peripheral components. Using LonRF devices, a home control network can be simplified and most devices can be operated on LonWorks control network. Also, Indoor Positioning System (IPS) that can serve various location based services was implemented in uHome-net. Smart Badge of IPS, that is a special LonRF device, can measure the 3D location of objects in the indoor environment. In the uHome-net testbed, remote control service, cooking help service, wireless remote metering service, baby monitoring service and security ＆ fire prevention service were realized. This research shows the vision of the ubiquitous home network that will be emerged in the near future.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제1권1호
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• pp.1-17
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• 2007

This paper proposes and analyzes a scalable and an efficient cluster based group key management protocol by introducing identity based infrastructure for secure communication in mobile wireless sensor networks. To ensure scalability and dynamic re-configurability, the system employs a cluster based approach by which group members are separated into clusters and the leaders of clusters securely communicate with each other to agree on a group key in response to changes in membership and member movements. Through analysis we have demonstrated that our protocol has a high probability of being resilient for secure communication among mobile nodes. Finally, it is established that the proposed scheme is efficient for secure positioning in wireless sensor networks.

• Journal of Advanced Marine Engineering and Technology
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• 제39권2호
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• pp.187-194
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• 2015

Accurate relative location estimation is a key requirement in indoor localization systems based on wireless sensor networks (WSNs). However, although these systems have applied not only various optimization algorithms but also fusion with sensors to achieve high accuracy in position determination, they are difficult to provide accurate relative azimuth and locations to users because of cumulative errors in inertial sensors with time and the influence of external magnetic fields. This paper based on ultra-wideband positioning system, which is relatively suitable for indoor localization compared to other wireless communications, presents an indoor localization system for estimating relative azimuth and location of location-unaware nodes, referred to as target nodes without applying any algorithms with complex variable and constraints to achieve high accuracy. In the proposed method, the target nodes comprising three mobile nodes estimate the relative distance and azimuth from two reference nodes that can be installed by users. In addition, in the process of estimating the relative localization information acquired from the reference nodes, positioning errors are minimized through a novel modified rounding estimation technique in which Kalman filter is applied without any time consumption algorithms. Experimental results show the feasibility and validity of the proposed system.

• Journal of information and communication convergence engineering
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• 제6권2호
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• pp.140-145
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• 2008

We recently developed new offshore observation system using USN buoy, widely used to measure the directional properties of ocean wave, seawater temperature, UV light, longitude and latitude of the buoy using GPS module. This paper also documents the development and implementation of a buoy network for acquisition of data of base station with buoys. The major phases of the project include specification of the network, physical construction of network nodes, software development for control of nodes, and testing of network performance. We described some of the practical issues involved in designing, building and deploying a buoy network for oceanographic monitoring. The paper explains some of the design decisions and their consequences, and some of the lessons learned from a first lesson network trial at sea.