scholarly journals A Practice of BLE RSSI Measurement for Indoor Positioning

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5181
Author(s):  
Ramiro Ramirez ◽  
Chien-Yi Huang ◽  
Che-An Liao ◽  
Po-Ting Lin ◽  
Hsin-Wei Lin ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Signal Strength ◽  
Propagation Distance ◽  
Signal Propagation ◽  
Propagation Model ◽  
Noisy Environment ◽  
Positioning Accuracy ◽  
Signal Stability ◽  
Wireless Signal ◽  
Three Dimensional Configuration

Bluetooth Low Energy (BLE) is one of the RF-based technologies that has been utilizing Received Signal Strength Indicators (RSSI) in indoor position location systems (IPS) for decades. Its recent signal stability and propagation distance improvement inspired us to conduct this project. Beacons and scanners used two Bluetooth specifications, BLE 5.0 and 4.2, for experimentations. The measurement paradigm consisted of three segments, RSSI–distance conversion, multi-beacon in-plane, and diverse directional measurement. The analysis methods applied to process the data for precise positioning included the Signal propagation model, Trilateration, Modification coefficient, and Kalman filter. As the experiment results showed, the positioning accuracy could reach 10 cm when the beacons and scanners were at the same horizontal plane in a less-noisy environment. Nevertheless, the positioning accuracy dropped to a meter-scale accuracy when the measurements were executed in a three-dimensional configuration and complex environment. According to the analysis results, the BLE wireless signal strength is susceptible to interference in the manufacturing environment but still workable on certain occasions. In addition, the Bluetooth 5.0 specifications seem more promising in bringing brightness to RTLS applications in the future, due to its higher signal stability and better performance in lower interference environments.

The Hybrid HMM for RSS-Based Localization in Wireless Sensor Networks

2013 ◽  
Vol 347-350 ◽  
pp. 796-802 ◽  
Author(s):  
Yan Hong Zang ◽  
Jin Song Wang ◽  
Lin Ling ◽  
Pei Zhong Lu
Keyword(s):  
Wireless Sensor Networks ◽  
Hidden Markov ◽  
Signal Strength ◽  
Threshold Value ◽  
Signal Propagation ◽  
Propagation Model ◽  
Wireless Sensor ◽  
Node Localization ◽  
Localization Accuracy ◽  
Signal Propagation Model

We proposea method of RSS-base localization in WSN (Wireless Sensor Network), called Hybrid HMM, to improve the stabilityof node localization basedon RSS(Received Signal Strength).This model utilizesHMM(Hidden Markov Model) to takeinto account the time factor when receiving the RSS sequence, andconverts the action of ranging into an operationof classification.For the received RSS used for localization,our Hybrid HMMwill compare it withthe preset RSS threshold value, and put the result into one of two categories for subsequent processing: If the received value is higher than the threshold value, the distance value will be drawn from the signal propagation model. If lower, the information will be obtained from a trained HMM. Experimental results show that the Hybrid HMM method can greatly improve the localization accuracy.

Research on Indoor 3D Location Technology Based on RSSI

2014 ◽  
Vol 696 ◽  
pp. 241-246 ◽  
Author(s):  
Bo Xin Mao ◽  
Shan Liu ◽  
Jian Ping Chai
Keyword(s):  
Real Time ◽  
Global Positioning System ◽  
Mobile Communication ◽  
Rapid Development ◽  
Three Dimensional ◽  
Propagation Model ◽  
Positioning System ◽  
Positioning Accuracy ◽  
Global Positioning ◽  
Positioning Method

With the rapid development of mobile communication, the GPS (Global Positioning System) which provides real-time global positioning system has not been able to meet the needs of the indoor accurate positioning. Through simulation, this paper implements the method of indoor three-dimensional positioning based on RSSI compared the positioning accuracy under several kinds of noise. We achieve the good indoor three-dimensional positioning method with the combination of cost, positioning accuracy and positioning precision through the filter and secondary positioning which establishes special propagation model for various different environments.

scholarly journals Improvement on Permeability of Cyclic Peptide/Peptidomimetic: Backbone N-Methylation as A Useful Tool

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 311
Author(s):  
Yang Li ◽  
Wang Li ◽  
Zhengshuang Xu
Keyword(s):  
Cyclic Peptides ◽  
Cyclic Peptide ◽  
Three Dimensional ◽  
Conformational Space ◽  
Cell Permeability ◽  
Relative Importance ◽  
Intrinsic Properties ◽  
Surface Areas ◽  
Synthetic Methodologies ◽  
Three Dimensional Configuration

Peptides have a three-dimensional configuration that can adopt particular conformations for binding to proteins, which are well suited to interact with larger contact surface areas on target proteins. However, low cell permeability is a major challenge in the development of peptide-related drugs. In recent years, backbone N-methylation has been a useful tool for manipulating the permeability of cyclic peptides/peptidomimetics. Backbone N-methylation permits the adjustment of molecule’s conformational space. Several pathways are involved in the drug absorption pathway; the relative importance of each N-methylation to total permeation is likely to differ with intrinsic properties of cyclic peptide/peptidomimetic. Recent studies on the permeability of cyclic peptides/peptidomimetics using the backbone N-methylation strategy and synthetic methodologies will be presented in this review.

ACOUSTIC THREE-DIMENSIONAL EFFECTS AROUND THE TAIWAN STRAIT: COMPUTATIONAL RESULTS

1999 ◽  
Vol 07 (01) ◽  
pp. 15-26 ◽  
Author(s):  
CHI-FANG CHEN ◽  
JANG-JIA LIN ◽  
DING LEE
Keyword(s):  
Field Data ◽  
Bottom Topography ◽  
Three Dimensional ◽  
Propagation Model ◽  
Computational Results ◽  
Submarine Canyons ◽  
Offshore Area ◽  
Ocean Environment ◽  
The Taiwan Strait ◽  
Good Agreement

A set of experiments were performed in the offshore area off the coasts of Taiwan and three-dimensional (3-D) measurements recorded. The 3-D effect on underwater propagation due to azimuthal variation of bottom topography is studied for the offshore regions southwest of Taiwan, where submarine canyons exist. A 3-D acoustic propagation model, FOR3D, is used to detect the 3-D effect. Computational results show that the 3-D effect is more prominent along the axis of the canyon than across it. Calculations show a very good agreement with field data, which indicate that the 3-D effect exists in this realistic ocean environment.

Radio Propagation Models: A Performance Analysis based Impact of Sparse and Dense Deployment of Nodes under Different Propagation Models in Mobile Ad-hoc Networks (MANETs)

2021 ◽  
Author(s):  
Altaf Hussain ◽  
Muhammad Rafiq Khan
Keyword(s):  
Ad Hoc Networks ◽  
Ad Hoc ◽  
Mobile Ad Hoc Network ◽  
Signal Strength ◽  
Propagation Model ◽  
Strong Impact ◽  
Propagation Models ◽  
Mobile Ad Hoc ◽  
Hoc Networks ◽  
The Impact

Abstract Mobile Ad-hoc Network (MANET) is the most emerging and fast expanding technology since the last two decades. One of the major issue and challenging area in MANET is the process of routing due to dynamic topologies and high mobility of mobile nodes. The exchange of information from source to a destination is known as the process of routing. Spectacular amount of attention has been paid by researchers to reliable routing in ad-hoc networks. Efficiency and accuracy of a protocol depends on many parameters in these networks. In addition to other parameters node velocity and propagation models are among them. Calculating signal strength at receiver is the responsibility of a propagation model while mobility of nodes is responsible for topology of the network. A huge amount of loss in performance is occurred due to variation of signal strength at receiver and obstacles between transmissions. Simulation tools are developed to analyze the weakness and strength of protocols along with different parameters that may impact the performance. The choice of a propagation models have an abundant effect on performance on routing protocols in MANET. In this research, it has been analyzed to check the impact of different propagation models on the performance of Optimized Link State Routing (OLSR) in Sparse and Dense scenarios in MANET. The simulation has been carried out in NS-2 by using performance metrics as average Throughput, average packet drop and average latency. The results predicted that propagation models and mobility has a strong impact on the performance of OLSR in considered scenarios.

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