• 한국멀티미디어학회논문지
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• 제25권2호
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• pp.280-286
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• 2022

In order to efficiently collect data, it is essential to locate the facilities and analyze the movement data. The current technology for location collection can collect data using a GPS sensor, but GPS has a strong straightness and low diffraction and reflectance, making it difficult for indoor positioning. In the case of indoor positioning, the location is determined by using wireless network technologies such as Wifi, but there is a problem with low accuracy as the error range reaches 20 to 30 m. In this paper, using BLE 4.2 built in Raspberry Pi, we implement Bluetooth Smart Ready. In detail, a beacon was produced for Advertise, and an experiment was conducted to support the serial port for data transmission/reception. In addition, advertise mode and connection mode were implemented at the same time, and a 3-count gradual algorithm and a quadrangular positioning algorithm were implemented for Bluetooth RSSI error correction. As a result of the experiment, the average error was improved compared to the first correction, and the error rate was also improved compared to before the correction, confirming that the error rate for position measurement was significantly improved.

• 제어로봇시스템학회논문지
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• 제19권2호
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• pp.119-124
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• 2013

Recent increasing demand on the indoor localization requires more advanced and hybrid technology. This paper proposes an application of the hybrid indoor localization method based on a position-coded pattern that can be used with other existing indoor localization techniques such as vision, beacon, or landmark technique. To reduce the pattern-recognition error rate, the error detection and correction algorithm was applied based on Hamming code. The indoor localization experiments based on the proposed algorithm were performed by using a QCIF-grade CMOS sensor and a position-coded pattern with an area of $1.7{\times}1.7mm^2$. The experiments have shown that the position recognition error ratio was less than 0.9 % with 0.4 mm localization accuracy. The results suggest that the proposed method could be feasibly applied for the localization of the indoor mobile service robots.

• 한국융합학회논문지
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• 제8권1호
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• pp.7-12
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• 2017

본 논문에서는 스마트폰의 BLE 광고 기술을 이용하여 별도의 BLE 디바이스 및 인프라 구축이 필요 없는 스마트폰을 이용한 전자출결시스템을 제안하였다. 기존의 BLE를 이용한 전자출결시스템은 서비스를 위해서는 BEL 디바이스를 각 강의실마다 부착해야 하며 강의실에 부착된 디바이스를 구분하기 위해서는 별도의 기술이 필요하였다. 또한 항시 동작하기 때문에 서로의 간섭으로 인하여 전자출결이 간혹 오류가 생기기도 하였다. 본 논문에서 제안한 전자출결시스템은 기존의 블루투스 비콘 방식의 전자출결시스템의 단점인 시스템 구축을 위한 비용적인 문제를 해결하고, 이동식 전자출결로서 활용이 가능하여 시간과 장소의 문제점을 해결할 수 있으며 별도의 BLE 디바이스 없이 본인이 사용 중인 스마트폰의 BLE(Bluetooth Low Energy) 광고 기능을 이용하여 전자출결을 위한 인프라 구축이 가능한 장점이 있다.

• 로봇학회논문지
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• 제2권1호
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• pp.40-47
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• 2007

Recently, with the development of service robots and with the new concept of ubiquitous world, the position estimation of mobile objects has been raised to an important problem. As pre-liminary research results, some of the localization schemes are introduced, which provide the absolute location of the moving objects subjected to large errors. To implement a precise and convenient localization system, a new absolute position estimation method for a mobile robot in indoor environment is proposed in this paper. Design and implementation of the localization system comes from the usage of active beacon systems (based upon RFID technology). The active beacon system is composed of an RFID receiver and an ultra-sonic transmitter: 1. The RFID receiver gets the synchronization signal from the mobile robot and 2. The ultra-sonic transmitter sends out the traveling signal to be used for measuring the distance. Position of a mobile robot in a three dimensional space can be calculated basically from the distance information from three beacons and the absolute position information of the beacons themselves. Since it is not easy to install the beacons at a specific position precisely, there exists a large localization error and the installation time takes long. To overcome these problems, and provide a precise and convenient localization system, a new auto calibration algorithm is developed in this paper. Also the extended Kalman filter has been adopted for improving the localization accuracy during the mobile robot navigation. The localization accuracy improvement through the proposed auto calibration algorithm and the extended Kalman filter has been demonstrated by the real experiments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권5호
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• pp.1317-1340
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• 2024

With the rapid development of information technology, people's demands on precise indoor positioning are increasing. Wireless sensor network, as the most commonly used indoor positioning sensor, performs a vital part for precise indoor positioning. However, in indoor positioning, obstacles and other uncontrollable factors make the localization precision not very accurate. Ultra-wide band (UWB) can achieve high precision centimeter-level positioning capability. Inertial navigation system (INS), which is a totally independent system of guidance, has high positioning accuracy. The combination of UWB and INS can not only decrease the impact of non-line-of-sight (NLOS) on localization, but also solve the accumulated error problem of inertial navigation system. In the paper, a fused UWB and INS positioning method is presented. The UWB data is firstly clustered using the Fuzzy C-means (FCM). And the Z hypothesis testing is proposed to determine whether there is a NLOS distance on a link where a beacon node is located. If there is, then the beacon node is removed, and conversely used to localize the mobile node using Least Squares localization. When the number of remaining beacon nodes is less than three, a robust extended Kalman filter with M-estimation would be utilized for localizing mobile nodes. The UWB is merged with the INS data by using the extended Kalman filter to acquire the final location estimate. Simulation and experimental results indicate that the proposed method has superior localization precision in comparison with the current algorithms.

• 공학교육연구
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• 제15권5호
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• pp.93-97
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• 2012

Most of ubiquitous computing devices such as stereo camera, ultrasonic sensor based MIT cricket system and other wireless sensor network devices are widely applied to the 2 Dimensional(2D) localization system in today. Because stereo camera cannot estimate the optimal location between moving node and beacon node in Wireless Personal Area Network(WPAN) under Non Line Of Sight(NLOS) environment, it is a great weakness point to the design of the 2D localization system in indoor environment. But the conventional 2D triangulation scheme that is adapted to the MIT cricket system cannot estimate the 3 Dimensional(3D) coordinate values for estimation of the optimal location of the moving node generally. Therefore, the 3D triangulation scheme based on the space segmentation in WPAN is suggested in this paper. The measuring data in the suggested scheme by computer simulation is compared with that of the geographic measuring data in the AutoCAD software system. The average error of coordinates values(x,y,z) of the moving node is calculated to 0.008m by the suggested scheme. From the results, it can be seen that the location correctness of the suggested scheme is very excellent for using the localization system in WPAN.

• 제어로봇시스템학회논문지
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• 제14권11호
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• pp.1139-1145
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• 2008

A robust position sensing system is proposed in this paper for a ubiquitous mobile robot which moves indoors as well as outdoors. The Differential GPS (DGPS) which has a position estimation error of less than 5 m is a general solution when the mobile robot is moving outdoor, while an active beacon system (ABS) with embedded ultrasonic sensors is reliable as an indoor positioning system. The switching from the outdoor to indoor or vice versa causes unstable measurements on account of the reference coordinates and algorithm changes. To minimize the switching time in the position estimation and to stabilize the measurement, a robust position sensing system is proposed. In the system, to minimize the switching delay, the door positions are stored and updated in a database. Using the database, the approaching status of the mobile robot from indoor to outdoor or vice versa has been checked and the switching conditions are prepared before the mobile robot actually moves out or moves into the door. The reliability and accuracy of the robust positioning system based on DGPS and ABS are verified and demonstrated through the real experiments using a mobile robot prepared for this research.

• 전기학회논문지
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• 제57권2호
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• pp.286-293
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• 2008

The design and implementation of a personal navigation system including activity monitoring function is given in this paper. The system consists of a 3 dimensional MEMS accelerometer, digital compasses and ZigBee communication. An accelerometer and digital compasses are used to compute the position and activity. The obtained position and activity information is transmitted to a fixed beacon via ZigBee. At the same time, activity information is stored in the personal navigation system to a batch analysis program. The step detection algorithm which is robust to attaching location is proposed. Also two digital compass error compensation algorithms are proposed to find more precise headings. The experiments with a real system show that the activities of users and continuous locations less than 1.5m errors are obtained after 80m walking.

• 한국컴퓨터정보학회논문지
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• 제24권5호
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• pp.41-47
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• 2019

A BIS(Bus Information System) collects, processes and analyzes information such as real-time location and operation status during bus operation. And It is a system that provides valid information to citizens, drivers, traffic centers and bus companies. Transport information system sent by an each bus is collected through GPS(Global Positioning System), DSRC(Dedicated Short Range Communications), Beacon and passed to transport information center. BIS data by collected is handled and analyzed. Next, it is transmitted to citizen, drivers and bus companies in real time. The result of 5 times simulation satisfied the test criteria(error range ${\pm}10m$) with an average error range of 3.306m, and the reliability is increased. In this paper, we propose a improved location transfer component that can provide users to quicker and more accurate location information than existing BIS using GPS of smart phone. It can be seen that reliability is improved by securing improved bus position data.

• 한국컴퓨터정보학회논문지
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• 제12권4호
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• pp.269-277
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• 2007

진보된 하드웨어 개발 기술 및 다양한 응용 가능성으로 인하여 무선 센서 네트워크 시스템이 현재 또는 미래에 주목받을 것으로 기대된다. 최근 다양한 응용 중에서 해안 및 수중 센서 네트워크 시스템에 대한 관심이 증대되고 있다. 센서 네크워크 시스템을 해양 및 수중에 적용하여 해양 자원 샘플링, 환경 모니터링, 재해 예방, 항로 유도 등 다양한 이점을 얻을 수 있다. 그러나 이러한 응용을 위해서 센서 노드의 위치 정보가 제공되어야 한다. 따라서 해양 및 수중 환경에서 센서 노드들의 위치 정보를 얻기 위해 순차적인 위치 파악(Sequential Localization) 알고리즘을 제안한다. 순차적 위치 파악은 해안가에 적은 수의 비콘 노드를 설치하여 센서 노드의 위치를 파악한다. 순차적인 위치 파악(Sequential Localization) 방법은 위치 에러 누적 현상을 완화하고 최대한 센서 노드들의 위치 파악을 위해 센서 노드들의 위치 파악 순서를 제어하여 위치 정보를 얻는다. 순차적 위치 파악은 센서 노드들의 레퍼런스 노드의 개수에 대한 정보를 가지고 각 센서 노드의 위치 파악 순서를 지정한다. 가장 많은 레퍼런스 노드를 가지는 센서 노드가 위치 파악 시 가장 높은 우선순위를 갖는다. 순차적 위치 파악 알고리즘은 위치 에러 성능뿐만 아니라 최대한의 센서 노드의 위치 좌표를 구하여 센서 네트워크의 커버리지 또한 증대시킨다.