• International Journal of Advanced Culture Technology
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• 제9권4호
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• pp.402-408
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• 2021

We are designed the delivery constitution technique that is to be measure the safe RFID statusof thewireless delivery system level (WDSL) on the delivery system tracking system. The delivery system level condition by the delivery system tracking system is organized with the RFID system. As to inspection a wireless network of the wireless network, we are found of the delivery value with wireless network by the upper take form. The concept of delivery system level is organized the reference of wireless level for delivery signal by the delivery RFID tracking system. Further, symbolizing a safe deliveryof the WDSL of the medium-minimum interval of the RFID tracking system, and the delivery wireless network RFID that was the delivery value of the far delivery of the DSTS-FA-_φMED-MIN with 5.80±1.20 units, that was the delivery value of the convenient delivery of the DSTS-CO-_φMED-MIN with 4.06±(-0.04) units, that was the delivery value of the flank delivery of the DSTS-_φMED-MIN with 0.91±0.07 units, that was the delivery value of the vicinage delivery of the DSTS-VI-_φMED-MIN with 0.18±(-0.03) units. The RFID will be to look into at the safe of the RFID tracking systemwith wireless network bythe delivery system level on the WDSL that is supply the wireless tracking system by the delivery system level system. We will be possible make to curb of a tracking system that to put the wireless signal and to use of the delivery data of RFID level by the delivery system.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.357-360
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• 2007

An asset tracking using wireless sensor network is concerned with geographical locations of sensor nodes. The limited size of sensor nodes makes them attractable for tracking service, at the same time their size causes power restrictions, limited computation power, and storage restrictions. Due to such constrained capabilities, the wireless sensor network basically assumes the failure of sensor nodes. This causes a set of concerns in designing asset tracking system on wireless sensor network and one of the most critical factors is location uncertainty of sensor nodes. In this paper, we classify the location uncertainty problem in asset tracking system into following cases. First, sensor node isn't read at all because of sensor node failure, leading to misunderstanding that asset is not present. Second, incorrect location is read due to interference of RSSI, providing unreliable location of asset. We implemented and installed our asset tracking system in a real environment and continuously monitored the status of asset and measured error rate of location of sensor nodes. We present experimental results that demonstrate the location uncertainty problem in asset tracking system using wireless sensor network.

• 항공우주시스템공학회지
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• 제3권4호
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• pp.35-40
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• 2009

The first purpose of this study is to develop a GCS(Ground Control System) by using RF(Radio Frequency) wireless communication equipments for UAV(Unmanned Aerial Vehicle). The second goal is to develop an antenna tracking system operating automatically. UAV receives flight data from a RF wireless system. So the role of antenna tracking system is very important to keep good communication state between UAV and GCS. GCS can check flight data and display a aviation state of UAV in real-time. The flight data displayed in real-time by GCS include the latitude, longitude, altitude, speed and so on. Experiments that measure a communication range and reliability are needed to develop a RF wireless communication system.

• Industrial Engineering and Management Systems
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• 제16권1호
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• pp.92-102
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• 2017

In this paper, we consider a typical health care system via the help of Wireless Sensor Network (WSN) for wireless patient tracking. The wireless patient tracking module of this system performs localization out of samples of Received Signal Strength (RSS) variations and tracking through a Particle Filter (PF) for WSN assisted by multiple transmit-power information. We propose a modified PF, Kullback-Leibler Distance (KLD)-resampling PF, to ameliorate the effect of RSS variations by generating a sample set near the high-likelihood region for improving the wireless patient tracking. The key idea of this method is to approximate a discrete distribution with an upper bound error on the KLD for reducing both location error and the number of particles used. To determine this bound error, an optimal algorithm is proposed based on the maximum gap error between the proposal and Sampling Important Resampling (SIR) algorithms. By setting up these values, a number of simulations using the health care system's data sets which contains the real RSSI measurements to evaluate the location error in term of various power levels and density nodes for all methods. Finally, we point out the effect of different power levels vs. different density nodes for the wireless patient tracking.

• 한국정보통신학회논문지
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• 제14권9호
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• pp.2120-2126
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• 2010

본 논문은 무선 센서네트워크에서 Zigbee를 적용한 위치추정시스템을 구현 하고자 하였다. 무선 센서네트워크는 유비쿼터스 환경에서 사용자기반의 위치인식 서비스를 제공한다. 위치인식 서비스는 사물이나 사람의 위치를 추정하고 이를 표현하여 제공한다. 본 논문에서 구현된 위치추정시스템은 실내 및 실외를 음영지역 없이 이동노드의 추정이 가능하도록 구현하였다. 실내추정의 경우 RSSI신호를 이용하며 실외추정의 경우 GPS를 연동하여 위치를 추정하였다. 또한 Zigbee를 적용하여 무선 센서네트워크 환경을 구축하고 이동노드의 위치를 제공받아 실시간 위치추정이 가능하도록 하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권5호
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• pp.998-1013
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• 2013

Wireless wearable sensor networks have emerged as a promising technique for human motion tracking due to the flexibility and scalability. In such system several wireless sensor nodes being attached to human limb construct a wearable sensor network, where each sensor node including MEMS sensors (such as 3-axis accelerometer, 3-axis magnetometer and 3-axis gyroscope) monitors the limb orientation and transmits these information to the base station for reconstruction via low-power wireless communication technique. Due to the energy constraint, the high fidelity requirement for real time rendering of human motion and tiny operating system embedded in each sensor node adds more challenges for the system implementation. In this paper, we discuss such challenges and experiences in detail during the implementation of such system with wireless wearable sensor network which includes COTS wireless sensor nodes (Imote 2) and uses TinyOS 1.x in each sensor node. Since our system uses the COTS sensor nodes and popular tiny operating system, it might be helpful for further exploration in such field.

• 전력전자학회논문지
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• 제25권5호
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• pp.404-411
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• 2020

Inductive power transfer (IPT) systems for electric vehicles generally require zero phase angle (ZPA) frequency tracking control to achieve high efficiency. Current sensors are used for ZPA frequency tracking control. However, the use of current sensors causes several problems, such as switching noise, degrading control performance, and control complexity. To solve these problems, this study proposes ZPA frequency tracking control without current sensors. Such control enables ZPA frequency tracking without real-time control and achieves stable zero voltage switching operation closed to ZPA frequency within all coupling coefficient and load ranges. The validity of the proposed control algorithm is verified on LCCL-S topology with a 3.3 kW rating IPT experimental test bed. Simulation verification is also performed.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.742-745
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• 2009

This paper proposes a wireless LAN antenna system that tracks an object automatically by using image-based tracking. The proposed system consists of a camera and a pan-tilt unit in addition to a directional wireless LAN antenna. The camera and the directional antenna are set in same direction and they are set on the pan-tilt unit. A target object which has a wireless LAN receiver is tracked by using images captured by the camera. And the directional antenna faces in same direction as the camera by the pan-tilt unit. Therefore, the directional antenna keeps pointing the receiver, and a transmitting efficiency is improved. A result of a fundamental experiment shows that a receiver attached to a flying airship was tracked by a prototype of the proposed antenna system. The airship flied about, and the proposed antenna system was set on a roof of a building. The experimental result indicates an effectiveness of the proposed system compared to the conventional directional LAN antenna.

• 한국컴퓨터정보학회논문지
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• 제13권7호
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• pp.67-73
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• 2008

본 논문에서는 무선 센서 노드의 실내 위치 추적 시스템을 제안한다. 위치 추정에 사용하는 센서 값으로 RF 인터페이스의 수신 신호 강도 (RSSI)를 사용한다. 이동 노드를 부착한 사용자와 실내에 고정된 다수의 고정 노드의 신호 강도를 수신하여 사용자의 위치를 결정한다. 제안한 시스템은 측정에 의한 2.4GHz log-normal path loss 모델의 수신강도와 유클리드 거리 계산 방법과 신호 강도를 결합한다. 실험결과를 통해서 1.3m 이내의 오차로 위치를 추정함을 확인하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1680-1684
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• 2010

CBTC(Communication-Based Train Control) system which is based on wireless communication can provide high density operation of the train using location tracking between ground and onboard train. It can also reduces maintenance expense because it does not require the ground equipment for tracking circuit and signal flag and so on. Recently, research and interest have been done on CBTC system. The high-speed trains up to 300km/h experience multi-path fading channel which bring about the performance degradation of wireless CBTC system. In this paper, we consider MIMO (Multi-Input Multi-Output) antenna-based CBTC system for trains with Alamoutip-type space-time diversity transmission for reliable communication. Also we model a channel considering practical environment and evaluate performance improvement of proposed CBTC system.