• 한국전자통신학회논문지
• /
• 제5권4호
• /
• pp.391-398
• /
• 2010

모바일 센서 네트워크는 기존의 위치가 고정된 무선 센서 네트워크와는 다르게 비컨 노드와 일반 노드가 모두 움직일 수 있기 때문에 위치 측정 알고리즘이 일반적인 무선 센서 네트워크 환경의 알고리즘 보다 어렵다. 특히 모바일 센서 네트워크에서 노드의 움직임이 빠를 경우 기존의 위치 측정 알고리즘으로는 원하는 시간 내에 위치를 측정할 수 없다. 본 연구에서는 이러한 모바일 센서 네트워크에서의 위치 측정 알고리즘을 제안하고 성능을 향상시켜 실시간에 위치를 측정할 수 있는 기법을 연구하였다.

• 대한전자공학회논문지TE
• /
• 제42권2호
• /
• pp.15-22
• /
• 2005

본 논문에서는 이동 로봇 주행의 경로 탐색에 장해가 되는 환경 인식의 불확실성을 감소시키기 위한 센서 결합 방식을 제시하였다. 광학식엔코더, 초음파센서(SRF04)및, 적외선센서(GP2YA02YK)에서 수집된 데이터를 운동제어기(TMS320LF2407A)에서 처리하여 장애물을 감지하고, 안정적인 경로탐색을 계산할 수 있는 이동로봇 제어방식을 실험을 통하여 구현하였다.

• ETRI Journal
• /
• 제38권3호
• /
• pp.551-559
• /
• 2016

In this paper, we propose a hybrid sensor calibration scheme for mobile crowdsensing applications. As the number of newly produced mobile devices containing embedded sensors continues to rise, the potential to use mobile devices as a sensor data source increases. However, because mobile device sensors are generally of a lower performance and cost than dedicated sensors, sensor calibration is crucial. To enable more accurate measurements of natural phenomena through the use of mobile device sensors, we propose a hybrid sensor calibration scheme for such sensors; the scheme makes use of mobile device sensors and existing sensing infrastructure, such as weather stations, to obtain dense data. Simulation results show that the proposed scheme supports low mean square errors. As a practical application of our proposed scheme, we built a temperature map of a city using six mobile phone sensors and six reference sensors. Thanks to the mobility of the sensors and the proposed scheme, our map presents more detailed information than infrastructure-based measurements.

• 대한전자공학회논문지TC
• /
• 제45권5호
• /
• pp.1-11
• /
• 2008

무선 센서 네트워크(Wireless Sensor Network : WSN)는 U-City 같은 우리 삶의 편의성 향상을 위한 서비스에 활용은 물론이거니와 환경오염, 터널 및 건축물의 붕괴, 태풍, 지진 등의 재난 감시, 위험물 진단 시스템 등에 다양하게 적용되고 있다. 본 논문에서는 이러한 WSN을 다양한 형태의 휴대 단말 및 네트워크 카메라와 연동하여 보다 효율적이고 가치 있는 정보 서비스 제공을 위한 MUSNEMO(Multi-sensor centric Ubiquitous Smart sensor NEtwork using MObile devices) 시스템을 제안하였다. 제안된 시스템은 IEEE 802.15.4 표준을 기반으로 스마트 센서 네트워크를 구성하며, 또한 제안한 시스템 구조의 활용성 검증을 위하여 다섯가지 응용 센서(자기, 조도, 소리, 모션, 진동)를 가진 망을 구성하여 센싱 이벤트 요청 및 제공 테스트를 수행하였다.

• 한국멀티미디어학회논문지
• /
• 제12권12호
• /
• pp.1778-1786
• /
• 2009

Many sensor network applications have been developed for smart home, disaster management, and a wide range of other applications. These applications, however, generally assume a fixed base station as well as fixed sensor nodes. Previous research on sensor networks mainly focused on efficient transmission of data from sensors to fixed sink nodes. Recently there has been active research on mobile sink nodes, sink mobility is one of the most comprehensive trends for information gathering in sensor networks, but the research of an environment where both fixed sink nodes and mobile sinks are present at the same time is rather scarce. This paper proposes a scheme for context-aware by ubiquitous devices with the sink functionality added through fixed sinks under a previously-built, cluster-based multi-hop sensor network environment. To this end, clustering of mobile devices were done based on the fixed sinks of a previously-built sensor network, and by using appropriate fixed sinks, context gathering was made possible. By mathematical comparison with TTDD routing protocol, which was proposed for mobile sinks, it was confirmed that performance increases by average 50% in energy with the number of mobile sinks, and with the number of movements by mobile devices.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• 제10권4호
• /
• pp.281-286
• /
• 2010

We propose a space and time based sensor fusion method and a robust landmark detecting algorithm based on sensor fusion for mobile robot navigation. To fully utilize the information from the sensors, first, this paper proposes a new sensor-fusion technique where the data sets for the previous moments are properly transformed and fused into the current data sets to enable an accurate measurement. Exploration of an unknown environment is an important task for the new generation of mobile robots. The mobile robots may navigate by means of a number of monitoring systems such as the sonar-sensing system or the visual-sensing system. The newly proposed, STSF (Space and Time Sensor Fusion) scheme is applied to landmark recognition for mobile robot navigation in an unstructured environment as well as structured environment, and the experimental results demonstrate the performances of the landmark recognition.

• 한국항행학회논문지
• /
• 제19권6호
• /
• pp.643-647
• /
• 2015

최근 센서와 네트워크 기술을 접목한 유비쿼터스 기술이 부각되고 있으며 이를 USN (ubiquitous sensor network)라 한다. 본 논문에서는 이러한 USN 기술을 기반으로 영유아의 건강과 안전을 관리하기 위해 스마트 센서를 이용한 Baby care 모바일 어플리케이션을 제안하고 개발하였다. 개발한 모바일 어플리케이션은 영유아의 낙상 감지, 울음 감지, 발열 감지 등의 정보를 개발한 모바일 어플리케이션의 화면에 나타내었다. 개발된 모바일 어플리케이션은 모의 실험을 통하여 확인하였다.

• 제어로봇시스템학회논문지
• /
• 제14권8호
• /
• pp.800-808
• /
• 2008

This paper presents a localization algorithm of the outdoor wheeled mobile robot using the sensor fusion method based on indirect Kalman filter(IKF). The wheeled mobile robot considered with in this paper is approximated to the two wheeled mobile robot. The mobile robot has the IMU and encoder sensor for inertia positioning system and GPS. Because the IMU and encoder sensor have bias errors, divergence of the estimated position from the measured data can occur when the mobile robot moves for a long time. Because of many natural and artificial conditions (i.e. atmosphere or GPS body itself), GPS has the maximum error about $10{\sim}20m$ when the mobile robot moves for a short time. Thus, the fusion algorithm of IMU, encoder sensor and GPS is needed. For the sensor fusion algorithm, we use IKF that estimates the errors of the position of the mobile robot. IKF proposed in this paper can be used other autonomous agents (i.e. UAV, UGV) because IKF in this paper use the position errors of the mobile robot. We can show the stability of the proposed sensor fusion method, using the fact that the covariance of error state of the IKF is bounded. To evaluate the performance of proposed algorithm, simulation and experimental results of IKF for the position(x-axis position, y-axis position, and yaw angle) of the outdoor wheeled mobile robot are presented.

• 전기학회논문지
• /
• 제59권9호
• /
• pp.1692-1698
• /
• 2010

In this paper we use wireless sensor network and ultrasonic sensors to estimate local position of mobile robots, and to navigate it. Ultra sonic sensor is simple and accurate so it is good to use in local estimation and navigation of mobile robots. But to obtain accurate distance of two sensors they need to face each others as possible as they can. To solve this problem we rotate ultra sonic sensor which is attached to robot in 360 degrees and obtain accurate distance. We can estimate precise position of mobile robot by triangulation using obtained distance information. A mobile robot navigates using embedded encoder and compensates its coordinates by ultrasonic sensors. Results of Experiments show proposed method obtains accurate distance between sensors and coordinates of position of robot. And mobile robots can navigate designated path well.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제7권9호
• /
• pp.2173-2193
• /
• 2013

In order to reduce the distribution cost of sensor nodes, a mobile sensor deployment has been proposed. The mobile sensor deployment can be solved by finding the optimal layout and planning the movement of sensor nodes with minimum energy consumption. However, previous studies have not sufficiently addressed these issues with an efficient way. Therefore, we propose a new deployment approach satisfying these features, namely a tree-based approach. In the tree-based approach, we propose three matching schemes. These matching schemes match each sensor node to a vertex in a rake tree, which can be trivially transformed to the target layout. In our experiments, the tree-based approach successfully deploys the sensor nodes in the optimal layout and consumes less energy than previous works.