• Korea Information Processing Society Review
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• v.22 no.6
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• pp.8-14
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• 2015

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.529-531
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• 2004

For localization, it is very important for an autonomous mobile robot to be able to recognize indoor environment and match an object it detect to an object within a map developed either online or offline. Given the map defining the locations of geometric beacons like wall and comer existing in the robot operation environment, this paper presents a stereo ultrasonic sensor based method that can be conveniently used in recognizing the geometric beacons. The stereo ultrasonic sensor used in the experiment consists of an ultrasonic transmitter and two ultrasonic receivers placed symmetrically about the transmitter. Experiment shows that the proposed method is more efficient in recognizing wall and coner than the conventional method of using multiple number of transmitter-receiver pairs.

• Journal of the Korean Institute of Navigation
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• v.12 no.1
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• pp.45-53
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• 1988

In this paper, the equations calculating GDOP are induced in Hyperboic, and Spherical Navigation System, respectively, The GDOP diagram shows that the DGOP in the inner region of Beacons is similar each other, but the GDOP of Hyperboic Navigation System is much larger than that of Spherical Navigation System due to GDOP in the outer region of Beacons. The authors propose the algorithm estimating the pulse starting time using the Hyperboic Navigation System, and prove that if Navigation use the Spherical Navigation System by adopting the proposed Algorithm -in this case, "Pseudo Sperical Navigation System" - in the outer region where GDOP is becoming large, the position errors can be reduced.e reduced.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.9
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• pp.925-930
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• 2008

Many sensor network applications require that each node's sensor data stream be annotated with its physical location in some coordinate system. Equipping GPS on every sensor node is often expensive and does not work in indoor deployments. Recently, cricket-based localization system is often used for indoor localization system. It is very important to know the exact position of beacons in cricket-based localization system for identifying moving sensor node's position. In this paper, a new method, Mobile Listener Detect Algorithm (MLD) which can automatically calculate the unknown newly installed beacons is proposed. For the verification of the feasibility of the proposed scheme, we have conducted several experiments.

• International Journal of Control, Automation, and Systems
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• v.6 no.4
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• pp.544-550
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• 2008

In this paper, an efficient positioning algorithm is proposed for a local positioning system using ultrasound and RF in WSN. The proposed positioning algorithm is the modified Savarese method where measurement noise characteristics are included as a weighting. Furthermore the ill-conditioned and the singularity problem occurred when all beacons are installed at the same height are removed. And the method is applicable to 2D positioning with 2 beacons only. The experiments with implemented system show the accurate seamless positioning less than 2cm error both static and dynamic experiments while the original Savarese method can not provide positions.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.6
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• pp.366-371
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• 2005

For an autonomous mobile robot localization, it is very important for the robot to be able to recognize indoor environment and match a detected object to an object defined within a map developed either online or of offline. Given the map defining the locations of geometric beacons like wall and corner existing in the robot operation environment, this paper presents a stereo ultrasonic sensor based method practically applicable in recognizing the geometric beacons in real-time. The stereo ultrasonic sensor used in the experiment consists of an ultrasonic transmitter and two ultrasonic receivers placed symmetrically about the transmitter Experimental results are provided to demonstrate that the proposed method is more efficient in recognizing wall and coner than the conventional method of using multiple number of transmitter-receiver pairs.

• Journal of information and communication convergence engineering
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• v.19 no.3
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• pp.161-165
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• 2021

Since the first commercialization of beacon-based services in 2011, various services have been provided to improve Bluetooth performance, and research has been conducted to accurately recognize user locations using beacons. The various measurement methods of indoor positioning systems (IPS) include methods using receiver signal strength indicator (RSSI) the strength of which varies greatly in accuracy depending on whether there are obstacles such as cement walls or doors. In this paper, we present a method to provide accurate positioning services even in the presence of obstacles in indoor spaces. To this end, we connect the HM-10 module supporting the beacon with Arduino Uno, to place beacons in three directions in real-world indoor space, and derive an optimal trilateration equation. Based on the derivation, we select the optimal expression for calculating the distance between the beacon and the moving station and use it to verify the coordinate determination for the moving station.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.6
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• pp.1-8
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• 2018

In this paper, we implement the signboard voice guidance service for visually impaired person using virtual beacon. The new location to provide a location-based service can be added easily by using virtual beacons, which are locating by Wi-fi, GPS, and so on, instead of physical beacons, which are locating by physical devices. We provide the voice service for guiding information of the captured signboard for the visually impaired when he arrived at the location registered through the virtual beacon.

• Journal of the Korea Society of Computer and Information
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• v.24 no.1
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• pp.159-166
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• 2019

Recently, the advanced development of smart devices has increased the interest in health-care, and many people are paying more attentions to disease prevention than disease treatment. Among these prevention methods, the bare body movement has received much attention, and especially walking exercise is attracting much attention because it is enjoyable without any restrictions on place and time. Walking exercise is generally divided into two types: walking on the ground and climbing the stairs. Walking up the stairs consumes much more calories compared to walking on the ground. These walking exercises have the advantage that they can be easily performed by male and female without special equipments or economic considerations. However, there is a lack of applications and systems that accurately determine such walking and stair walking and measure momentum according to stair walking. In this paper, we designed and implemented a real-time walking status analysis system using smartwatch's, pedometer, smartphone's barometer and beacons.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.707-708
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• 2009

In this paper, we provide a tradeoff solution to two conflicting requirements in VANET; Privacy and Aggregation. The information about traffic density is an important factor of aggregation in VANET. In our proposed scheme, densely located Road-Side Units (RSU) perform traffic density calculation and then aggregate the traffic information extracted from beacons received from the vehicles. RSUs then disseminate the aggregated traffic information to all the vehicles and neighbor RSUs. We use identityless beaconing thereby providing privacy and we do not consider the content security of beacons. We show that our scheme provides privacy in the case of aggregation, which has not been considered in previous schemes.