• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2004년도 춘계학술발표대회
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• pp.1529-1532
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• 2004

A Mobile Ad Hoc NETwork (MANET) is a collection of wireless mobile nodes that forms a temporary network without the need for any existing network infrastructure or centralized administration. Therefore, such a network is designed to operate in a highly dynamic environment due to node mobility. In mobile ad hoc network, frequent topological changes cause routing a challenging problem and without the complete view of the network topology, establishing the shortest path from the source node to the destination node is difficult. In this paper, we suggest a routing approach which utilizes location information to setup the shortest possible path between the source node and the destination node. Location information is obtained through Global Positioning System (GPS) and this geographical coordinate information of the destination node is used by the source node and intermediate nodes receiving route request messages to determine the shortest path to the destination from current node.

• Journal of electromagnetic engineering and science
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• 제17권4호
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• pp.181-185
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• 2017

In this paper, we propose an angle-of-arrival (AoA)-based local positioning system using a time-modulated array (TMA). The proposed system can determine a two-dimensional position using only two TMAs without any synchronization between the two receivers. The hardware for the proposed system consists of two commercial monopole antennas, a self-designed switch, and a well-known software-defined radio receiver. Furthermore, the location can be simply estimated in real time without the need for complicated positioning algorithms such as the MUSIC and ESPRIT algorithms. In order to evaluate the performance of our system, we estimated the position of the wireless node in an office environment. The position was estimated with a mean error of less than 0.1 m. We therefore believe that our system is appropriate for various wireless local positioning applications.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권2호
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• pp.405-423
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• 2022

The distance vector-hop (DV-Hop) is one of the emblematic algorithms that use node connectivity for locating, which often accompanies by a large positioning error. To reduce positioning error, the bio-inspired algorithm and weight optimization model are introduced to address positioning. Most scholars argue that the weight value decreases as the hop counts increases. However, this point of view ignores the intrinsic relationship between the error and weight. To address this issue, this paper constructs the relationship model between error and hop counts based on actual communication characteristics of sensor nodes in wireless sensor network. Additionally, we prove that the error converges to 1/6CR when the hop count increase and tendency to infinity. Finally, this paper presents a modified error-oriented weight positioning model, and implements it with genetic algorithm. The experimental results demonstrate excellent robustness and error removal.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.227-230
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• 2011

본 논문에서는 ALPS(Ad hoc network Localized Positioning System)알고리즘에 의해 위치 정보를 받아 새로운 헤드 노드를 에너지 효율성을 고려하여 선출하는 ECOPS(Energy Conserving optimal Path Schedule)알고리즘을 제안한다. 제안된 알고리즘은 계층적 클러스터 구조인 상황인식 기반의 RODMRP(Resilient Ontology-based Dynamic Multicast Routing Protocol) 추론망 구조를 따르며, 노드의 위치 정보를 이용하여 에너지 효율적인 클러스터를 생성 및 유지하고, 전체 라우팅 구조의 라이프 타임을 증가시키는 방법이다.

• 한국멀티미디어학회논문지
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• 제22권9호
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• pp.1011-1019
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• 2019

In this paper, we propose a system that can more precisely identify and monitor the position of the tool used in the assembling workplace such as automobile production. The proposed positioning monitoring system is a combination of UWB communication module and MEMS IMU sensor. Since UWB does not need modulation and demodulation function and has low power density, UWB is widely used in indoor positioning field. However, it may cause positioning error due to errors in RF transmission and reception process, which may cause positioning accuracy. Therefore, in this paper, we propose an algorithm that uses IMU as an auxiliary means to compensate for errors that may occur in positioning using only UWB. The tag and anchor of UWB module measure the transmission / reception time by transmitting signals to each other and then estimate the distance between tag and anchor. The MEMS IMU sensor serves to provide positioning calibration information. The tag, which is a mobile node and attached to a moving tool, measures the three-dimensional position of the tool and transfers the coordinate data to the anchor. Thus, it is possible to confirm whether or not the specific tool is properly used according to the prescribed regulations.

• Journal of Positioning, Navigation, and Timing
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• 제8권4호
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• pp.193-200
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• 2019

The auto-encoder network which is a good candidate to handle the modeling of the signal strength attenuation is designed for denoising and compensating the distortion of the received data. It provides a non-linear mapping function by iteratively learning the encoder and the decoder. The encoder is the non-linear mapping function, and the decoder demands accurate data reconstruction from the representation generated by the encoder. In addition, the adaptive network width which supports the automatic generation of new hidden nodes and pruning of inconsequential nodes is also implemented in the proposed algorithm for increasing the efficiency of the algorithm. Simulation results show that the proposed method can improve the neural network training surface to achieve the highest possible accuracy of the signal modeling compared with the conventional modeling method.

• ETRI Journal
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• 제39권2호
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• pp.264-274
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• 2017

Recently, mobile positioning enhancement has attracted much attention in the 3rd generation partnership project long-term evolution system. In particular, for urban canyon environments, the need for three-dimensional (3D) positioning has increased to enable the altitude of users to be measured. For several decades, several time difference of arrival (TDOA-) based 3D positioning methods have been studied; however, they are only available when at least four evolved Node Bs (eNBs) exist nearby or when all eNBs have the same height. Therefore, in this paper, we propose a new 3D positioning method that estimates the 3D coordinates of a user using three types of two-dimensional (2D) TDOAs. However, the give inaccurate results owing to the undefined axis of the 2D coordinate plane. Therefore, we propose a novel derivation of the hyperbola equation, which includes the undefined axis coordinate in the 2D hyperbola equation. Then, we propose an interaction algorithm that mutually supplies the undefined axis coordinate of users among 2D TDOAs. By performing extensive simulations, we verify that the proposed method is the only solution applicable by using three eNBs with different heights.

• Journal of Information Processing Systems
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• 제19권3호
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• pp.377-384
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• 2023

The existence of abnormal breakpoint data leads to poor channel balance in wireless sensor networks (WSN). To enhance the communication quality of WSNs, a method for positioning abnormal breakpoint data in WSNs on the basis of signal reconstruction is studied. The WSN signal is collected using compressed sensing theory; the common part of the associated data set is mined by exchanging common information among the cluster head nodes, and the independent parts are updated within each cluster head node. To solve the non-convergence problem in the distributed computing, the approximate term is introduced into the optimization objective function to make the sub-optimization problem strictly convex. And the decompressed sensing signal reconstruction problem is addressed by the alternating direction multiplier method to realize the distributed signal reconstruction of WSNs. Based on the reconstructed WSN signal, the abnormal breakpoint data is located according to the characteristic information of the cross-power spectrum. The proposed method can accurately acquire and reconstruct the signal, reduce the bit error rate during signal transmission, and enhance the communication quality of the experimental object.

• 한국통신학회논문지
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• 제35권12A호
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• pp.1128-1135
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• 2010

실내 무선 측위를 위한 UWB (Ultra Wide Band) 무선 측위 시스템에서는 정확한 위치 정보를 추정하기 위해 거리 인지 정보를 사용한다. 거리 인지를 위해서는 TOA (Time of Arrival), TDOA (Time Difference of Arrival)와 같은 시간 정보를 기반으로 하는 기법을 사용하는 것이 일반적이며, 시간 정보를 측정하기 위해서는 흔히 클럭 정보를 사용하는데, 이 때 가장 기본적으로 고려해야할 요소가 클럭 동기를 맞추는 것과 클럭 오프셋에 의한 오차를 보상하는 것이다. 본 논문에서는 이를 해결하기 위해 공통 클럭을 이용한 거리 인지 및 무선 측위 기술을 제안한다. 제안하는 무선 측위 기술의 성능 검증을 위하여 IEEE 802.15.4a TG에서 제시한 채널 환경에서 공통 클럭을 이용한 측위 시스템의 거리 인지 및 우선 측위 결과를 확인하기 위한 실험을 진행하였으며, 모의실험 결과를 통하여 클럭 오프셋에 영향을 받지 않는 우선 측위 결과를 얻을 수 있음을 확인하였다.

• 전기전자학회논문지
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• 제11권4호
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• pp.297-306
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• 2007

A sensor network is composed of a large number of sensor nodes that are densely deployed in a field. Each sensor performs a sensing task for detection specific events. After detecting this event, location information of the sensor node is very important. Range-based scheme of the proposed approaches typically achieve high accuracy on either node-to-node distances or angles, but this scheme have a drawback because all sensor nodes have the special hardware. On the other hand, range-free scheme provides economic advantage because of no needed hardware even if that leads to coarse positioning accuracy. In this paper, we propose a range-free localization algorithm without range information in wireless sensor networks. This is a range-free approach and uses a small number of anchor nodes and known sensor nodes. This paper develops a localization mechanism using the geometry conjecture (perpendicular bisector of a chord). The conjecture states that a perpendicular bisector of a chord passes through the center of the circle.