• Smart Media Journal
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• v.8 no.4
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• pp.85-90
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• 2019

The Ultra-Wide Band sensor is widely used as a wireless indoor localization technology with frequency bands in the GHz range. Meanwhile, in museums, not only the real-time location of visitors but also information on visit route and duration time is required for patrons' behavior analysis. In this paper, the analysis system based Ultra-Wide Band radar for visitor's viewing behavior is introduced and experimented in the real environment. We built the system in National Museum of Korea, and its 22 Ultra-Wide Band radar sensors receive the real-time location of their visitors: this analyzes the visit route and visit time for patrons.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.1
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• pp.32-38
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• 2012

Each sensor node can know its location in several ways, if the node process the information based on its geographical position in sensor networks. In the localization scheme using GPS, there could be nodes that don't know their locations because the scheme requires line of sight to radio wave. Moreover, this scheme is high costly and consumes a lot of power. The localization scheme without GPS uses a sophisticated mathematical algorithm estimating location of sensor nodes that may be inaccurate. AHLoS(Ad Hoc Localization System) is a hybrid scheme using both GPS and location estimation algorithm. In AHLoS, the GPS node, which can receive its location from GPS, broadcasts its location to adjacent normal nodes which are not GPS devices. Normal nodes can estimate their location by using iterative triangulation algorithms if they receive at least three beacons which contain the position informations of neighbor nodes. But, there are some cases that a normal node receives less than two beacons by geographical conditions, network density, movements of nodes in sensor networks. We propose an indirect localization scheme for low-density sensor nodes which are difficult to receive directly at least three beacons from GPS nodes in wireless network.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.4
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• pp.223-228
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• 2011

In this paper, a novel range-free localization algorithm for anisotropic networks is proposed. In the proposed method, the characteristics of the given network are considered and each sensor node estimates the relation between the hop counts and the geographical distances. Unlike most of the previous localization algorithms, the proposed method performs well not only in the isotropic network but also in the anisotropic networks. The proposed method is applied to both isotropic and anisotropic network topologies and the simulation results demonstrate that the method exhibits excellent and robust performances.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1884-1885
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• 2011

In the wireless sensor network (WSN) environment, the approximate point-in-triangulation (APIT) is a kind of range-free localization algorithm. This algorithm provides high precision, however, the coverage rate is somewhat poor. In this paper, we propose an improved APIT algorithm for the localization of swarm robots, which is based on the received signal strength indicator (RSSI) and the center of gravity (COG) methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5A
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• pp.521-528
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• 2011

In sensor network environment, it is very important to localize sensor nodes. In order to know the position of nodes without GPS signals, the anchor robot approach is representatively used. Therefore, in this paper, we propose 4-Robot Localization Scheme (4RLS) that uses four mobile robots to efficiently localize sensor nodes for the fast time. Then, we show the improved performance of 4RLS in comparison with previously used three robot scheme through the real implementation and analysis.

• Journal of Communications and Networks
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• v.18 no.3
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• pp.397-410
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• 2016

This paper proposes a novel cooperative localization method for distributed wireless networks in 3-dimensional (3D) global positioning system (GPS) denied environments. The proposed method, which is referred to as hybrid ellipsoidal variational algorithm (HEVA), combines the use of non-parametric belief propagation (NBP) and variational Bayes (VB) to benefit from both the use of the rich information in NBP and compact communication size of a parametric form. InHEVA, two novel filters are also employed. The first one mitigates non-line-of-sight (NLoS) time-of-arrival (ToA) messages, permitting it to work well in high noise environments with NLoS bias while the second one decreases the number of calculations. Simulation results illustrate that HEVA significantly outperforms traditional NBP methods in localization while requires only 50% of their complexity. The superiority of VB over other clustering techniques is also shown.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.64-69
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• 2008

In order that a mobile robot can perform tasks in unknown environment localization of a mobile robot is essential task. In this paper, a new localization method for a mobile robot using an active landmark is proposed, which is very simple to implement. The landmark has a LED which can be controlled by a mobile robot via wireless communication. CCD camera gets two images of the landmark, one of which is with LED off and the other is with LED on. Because the landmark can be detected by using the difference image of the two images, detection time can be minimized. By using the characteristic points of the landmark, localization can be performed simply. A series of experiments are performed to evaluate the proposed method and the experimental results show that the proposed method can be applicable to the localization of a mobile robot.

• Journal of the Korea Society of Computer and Information
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• v.15 no.1
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• pp.111-118
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• 2010

The proposed algorithm to be explained in this paper is the localization technique using directional antenna. Here, it is assumed that anchor node has the ability to transfer the azimuth of each sector using GPS modules, sector antenna, and the digital compass. In the conventional sensor network, the majority of localization algorithms were capable of estimating the position information of the sensor node by knowing at least 3 position values of anchor nodes. However, this paper has proposed localization algorithm that estimates the position of nodes to continuously move with sensor nodes and traveling nodes. The proposed localization mechanisms have been simulated in the Matlab. The simulation results show that our scheme performed better than other mechanisms (e.g. MCL, DV-distance).

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.07a
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• pp.79-81
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• 2016

무선 센서 네트워크 환경에서 사건을 탐지하거나 정보를 추적하는 등의 업무를 수행하기 위해 센서 노드가 있는 곳의 위치를 측정하는 문제는 매우 중요한 문제이다. DV-Hop 알고리즘은 위치를 알 수 없는 미지 노드들이 비콘 노드가 전송한 비콘과 홉거리 정보를 이용하여 센서 노드의 위치를 찾는 방법으로 거리 오차가 크다고 할 수 있다. 본 논문에서는 비콘 노드와 미지 노드 사이의 통신 반경 측정을 통하여 DV-Hop 알고리즘을 개선하고, MATLAB을 이용하여 개선 알고리즘의 성능을 평가하였다.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.426-428
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• 2004

Sensor network supports data delivery from physical world to cyber space Sensors get physical events then wireless network transfers sensor data to service server. We use sensor network technology to manage location information of asset. In ubiquitous computing environment, user localization is basic context for intelligent service. A lot of research group make effort to develop low cost localization technology. In this paper, we propose asset monitoring system using wireless sensor network. It is implemented using ad hoc network technology which can be adopted to smart home and this system can monitor the asset location and movement.