scholarly journals Fingerprinting/indoor positioning using complex planar splines

2021 ◽  
Vol 72 (6) ◽  
pp. 401-406
Author(s):  
Irina Strelkovskaya ◽  
Irina Solovskaya ◽  
Juliya Strelkovska
Keyword(s):  
Rapid Development ◽  
The Finite Element Method ◽  
High Concentration ◽  
Linear Complex ◽  
Positioning Accuracy ◽  
Location Determination ◽  
Current Location ◽  
Local Methods ◽  
Radio Signals ◽  
Improved Methods

Abstract The rapid development of various LBS-based applications and services that operate on the basis of the user’s current location, both global GPS and local LBS, today require the development of new and improved methods. This concerns, first of all, methods for determining the local location of LPS users in premises, if there is a high concentration of users and the presence of difficulties in the propagation of radio signals. the use of local methods of location determination based on the fingerprinting method is considered. It is shown that to improve the user positioning accuracy, it is expedient to use a combination of several methods. to determine the local location of the user, a method based on the finite element method and linear complex planar splines is proposed. the construction of linear complex planar splines is considered, their coefficients are found. finding the error in determining the coordinates of the user’s UE location is shown. The use of the proposed method will improve the accuracy of determining the coordinates of the user’s location and will ensure the provision of LBS services and applications to users in the premises under various conditions of their provision.

scholarly journals GPS AND GLONASS COMBINED STATIC PRECISE POINT POSITIONING (PPP)

2016 ◽  
Vol XLI-B1 ◽  
pp. 483-488 ◽  
Author(s):  
D. Pandey ◽  
R. Dwivedi ◽  
O. Dikshit ◽  
A. K. Singh
Keyword(s):  
Precise Point Positioning ◽  
Rapid Development ◽  
Three Dimensional ◽  
Global Navigation Satellite Systems ◽  
Open Pit ◽  
Positioning Accuracy ◽  
Dilution Of Precision ◽  
Satellite Visibility ◽  
Point Positioning ◽  
Gps Observations

With the rapid development of multi-constellation Global Navigation Satellite Systems (GNSSs), satellite navigation is undergoing drastic changes. Presently, more than 70 satellites are already available and nearly 120 more satellites will be available in the coming years after the achievement of complete constellation for all four systems- GPS, GLONASS, Galileo and BeiDou. The significant improvement in terms of satellite visibility, spatial geometry, dilution of precision and accuracy demands the utilization of combining multi-GNSS for Precise Point Positioning (PPP), especially in constrained environments. Currently, PPP is performed based on the processing of only GPS observations. Static and kinematic PPP solutions based on the processing of only GPS observations is limited by the satellite visibility, which is often insufficient for the mountainous and open pit mines areas. One of the easiest options available to enhance the positioning reliability is to integrate GPS and GLONASS observations. This research investigates the efficacy of combining GPS and GLONASS observations for achieving static PPP solution and its sensitivity to different processing methodology. Two static PPP solutions, namely standalone GPS and combined GPS-GLONASS solutions are compared. The datasets are processed using the open source GNSS processing environment <i>gLAB</i> 2.2.7 as well as <i>magicGNSS</i> software package. The results reveal that the addition of GLONASS observations improves the static positioning accuracy in comparison with the standalone GPS point positioning. Further, results show that there is an improvement in the three dimensional positioning accuracy. It is also shown that the addition of GLONASS constellation improves the total number of visible satellites by more than 60% which leads to the improvement of satellite geometry represented by Position Dilution of Precision (PDOP) by more than 30%.

scholarly journals Self-Assisted First-Fix Method for A-BDS Receivers with Medium- and Long-Term Ephemeris Extension

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Zilong Shen ◽  
Jing Peng ◽  
Wenxiang Liu ◽  
Feixue Wang ◽  
Shibing Zhu ◽  
...  
Keyword(s):  
Dynamic Models ◽  
Rapid Development ◽  
Real Data ◽  
Satellite System ◽  
Time Interval ◽  
Signal Acquisition ◽  
Positioning Accuracy ◽  
Broadcast Ephemeris ◽  
Intelligent Logistics

As a sensor for standalone position and velocity determination, the BeiDou Navigation Satellite System (BDS) receiver is becoming an important part of the intelligent logistics systems under rapid development in China. The applications in the mass market urgently require the BDS receivers to improve the performance of such functions, that is, shorter Time to First Fix (TTFF) and faster navigation signal acquisition speed with Ephemeris Extension (EE) in standalone mode. As a practical way to improve such functions of the Assisted BDS (A-BDS) receivers without the need for specialized hardware support, a Self-Assisted First-Fix (SAFF) method with medium- and long-term EE is proposed in this paper. In this SAFF method, the dynamic Medium- and Long-Term Orbit Prediction (MLTOP) method, which uses the historical broadcast ephemeris data with the optimal configuration of the dynamic models and orbit fitting time interval, is utilized to generate the extended ephemeris. To demonstrate the performance of the MLTOP method used in the SAFF method, a suit of tests, which were based on the real data of broadcast ephemeris and precise ephemeris, were carried out. In terms of the positioning accuracy, the overall performance of the SAFF method is illustrated. Based on the characteristics of the medium- and long-term EE, the simulation tests for the SAFF method were conducted. Results show that, for the SAFF method with medium- and long-term EE of the BeiDou MEO/IGSO satellites, the horizontal positioning accuracy is about 12 meters, and the overall positioning accuracy is about 25 meters. The results also indicate that, for the BeiDou satellites with different orbit types, the optimal configurations of the MLTOP method are different.

A User Profile Awareness Service Collaborative Recommendation Algorithm Under LBSN Environment

2019 ◽  
Vol 28 (03) ◽  
pp. 1950008
Author(s):  
Mingjun Xin ◽  
Lijun Wu ◽  
Shunxian Li
Keyword(s):  
Social Influence ◽  
Rapid Development ◽  
User Profile ◽  
Mobile Internet ◽  
Superior Performance ◽  
Mobile Service ◽  
Data Sparsity ◽  
Collaborative Recommendation ◽  
Current Location ◽  
Sparsity Problem

Nowadays, location-based social network (LBSN) has become one of the most popular applications with the rapid development of mobile Internet. However, due to the spatial and real-time properties, mobile service recommendation under LBSN environment faces too many challenges especially data sparsity problem. To tackle these challenges, a recommendation framework is proposed in this paper which has four layers defined as data collection layer, user profile modeling layer, information processing layer and recommendation feedback layer, respectively. Furthermore, the ISC-CF algorithm is implemented to integrate users’ interest profile, social influence and current location context to effectively overcome the data sparsity problem. Thus, the social influence is quantified by a modified measure way. Finally, a dynamic and personalized adjustment algorithm is built by using the users’ profile tracking and the current location context. The experiment results show that the algorithm proposed in this paper has significantly superior performance compared with the other baseline recommendation methods in both hometown area and out-of-town area.

RFID-Enabled Location Determination Within Indoor Environments

2009 ◽  
Vol 1 (4) ◽  
pp. 63-86 ◽  
Author(s):  
Kevin Curran ◽  
Stephen Norrby
Keyword(s):  
Supply Chain ◽  
Radio Frequency ◽  
Radio Frequency Identification ◽  
Automatic Identification ◽  
Indoor Environments ◽  
Location Determination ◽  
Asset Tracking ◽  
Current Location ◽  
Toll Collection ◽  
Main Components

The ability to track the real-time location and movement of items or people offers a broad range of useful applications in areas such as safety, security and the supply chain. Current location determination technologies, however, have limitations that heavily restrict how and where these applications are implemented, including the cost, accuracy of the location calculation and the inherent properties of the system. The Global Positioning System (GPS), for example, cannot function indoors and is useful only over large-scaled areas such as an entire city. Radio Frequency Identification (RFID) is an automatic identification technology which has seen increasingly prominent use over the last few decades. The technology uses modulated Radio Frequency signals to transfer data between its two main components, the reader and the transponder. Its many applications include supply chain management, asset tracking, security clearance and automatic toll collection. In recent years, advancements in the technology have allowed the location of transponders to be calculated while interfacing with the reader. This article documents an investigation into using an active RFID based solution for tracking.

A simple approach to estimate coastal soil salinity using digital camera images

Soil Research ◽  
2020 ◽  
Vol 58 (8) ◽  
pp. 737
Author(s):  
Lu Xu ◽  
Raphael A. Viscarra Rossel ◽  
Juhwan Lee ◽  
Zhichun Wang ◽  
Hongyuan Ma
Keyword(s):  
Soil Salinity ◽  
Precision Agriculture ◽  
Mean Squared Error ◽  
Rapid Development ◽  
Salt Content ◽  
Digital Camera ◽  
Soil Surface ◽  
Coefficient Of Determination ◽  
Least Squares Regression ◽  
High Concentration

Soil salinisation is a global problem that hinders the sustainable development of ecosystems and agricultural production. Remote and proximal sensing technologies have been used to effectively evaluate soil salinity over large scales, but research on digital camera images is still lacking. In this study, we propose to relate the pixel brightness of soil surface digital images to the soil salinity information. We photographed the surface of 93 soils in the field at different times and weather conditions, and sampled the corresponding soils for laboratory analyses of soil salinity information. Results showed that the pixel digital numbers were related to soil salinity, especially at the intermediate and higher brightness levels. Based on this relationship, we employed random forest (RF) and partial least-squares regression (PLSR) to model soil salt content and ion concentrations, and applied root mean squared error, coefficient of determination and Lin’s concordance correlation coefficient to evaluate the accuracy of models. We found that ions with high concentration were estimated more accurately than ions with low concentrations, and RF models performed overall better than PLSR models. However, the method is only suitable for bare land of coastal soil, and verification is needed for other conditions. In conclusion, a new approach of using digital camera images has good potential to predict and manage soil salinity in the context of precision agriculture with the rapid development of unmanned aerial vehicles.

Performances of HSK Spindle/Toolholder Interface for HSM

2006 ◽  
Vol 532-533 ◽  
pp. 269-272
Author(s):  
Song Zhang ◽  
Xing Ai ◽  
Jian Feng Li ◽  
Xiu Li Fu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Distribution ◽  
Contact Stress ◽  
High Speed ◽  
Rapid Development ◽  
High Speed Machining ◽  
The Finite Element Method ◽  
Axial Movement ◽  
Contact Stress Distribution

With the rapid development of high-speed machining technology, more and more machining centers have been equipped with the HSK toolholders. In this paper, the performances of the HSK spindle/toolholder interface, such as the axial movement, the radial deflection and the contact stress distribution, were simulated by means of the finite element method and compared with the traditional BT interface. From the simulated results, it was pointed out that the performances of the HSK interface were obviously superior to that of the BT interface, and the HSK interface was much more suitable for high-speed machining.

Preparation of cell populations with stabilized erythropoietic potential from the primitive streak chick blastodisc: Some implications for control of gastrulation

1978 ◽  
Vol 56 (6) ◽  
pp. 430-439 ◽  
Author(s):  
S. D. Wainwright ◽  
Lillian K. Wainwright
Keyword(s):  
Egg Yolk ◽  
Primitive Streak ◽  
Cell Suspensions ◽  
Erythroid Cells ◽  
High Concentration ◽  
Differentiated Cells ◽  
Viable Cells ◽  
Large Numbers ◽  
Cell Dispersion ◽  
Improved Methods

Improved methods for preparation from primitive streak chick blastodiscs of cell suspensions capable of forming erythroid cells in culture have been developed. When blastodiscs were preincubated with hyaluronidase in the absence of collagenase before cell dispersion and a high concentration of methyl-α-mannoside was present in all media, the yields of cells were some 10-fold higher than those obtained by former procedures. Cell suspensions obtained consisted almost entirely of viable cells, yielded large numbers of free mature erythrocytes in liquid culture, and formed erythroid colonies and bursts in solidified medium. The capacity to form differentiated cells after re sedimentation through Ficoll density gradients was partly stabilized.Addition of egg yolk homogenate to the blastodiscs immediately following treatment with hyaluronidase and to all media used thereafter largely stabilized the capacity to form erythroid cells during re sedimentation through Ficoll density gradients.Possible relevance of observations made during development of the procedures to the control of onset of cell migration in the process of gastrulation is indicated.

scholarly journals A New Approach for Wi-Fi-Based People Localization in a Long Narrow Space

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Longshi Gao ◽  
Shuangxia Tang ◽  
Yuntian Brian Bai
Keyword(s):  
Promising Result ◽  
Rapid Development ◽  
Shopping Malls ◽  
Positioning Accuracy ◽  
New Approach ◽  
Straight Line ◽  
Effective Technology ◽  
Public Areas ◽  
Narrow Space ◽  
Dual Connection

Wi-Fi-based positioning technology has been recognized as an effective technology for indoor positioning along with the rapid development and application of smartphones. One of its typical applications is localizing people in large public areas such as shopping malls, schools, and airports. A common and critical task from such applications is localizing people in long narrow spaces such as a long corridor which is considered as the most frequent place where people activities take place. Generally, the geographical distribution of Wi-Fi access points (APs) in long spaces is poor for localizing people since normally less than 3 APs are connected to a smartphone. In addition, all these APs are normally mounted along a straight line; hence, it is difficult to track people using traditional positioning algorithms such as trilateration and fingerprinting. To address this issue, a new approach called same-line-dual-connection (SLDC) was developed to estimate user locations with a good positioning accuracy, particularly for long narrow spaces where only limited Wi-Fi connections are available. The SLDC approach integrates geometry principle with positioning theories and machine learning ideas. The test outcome has shown that the SLDC approach produced a promising result, and a mean positioning accuracy of 1.60 m was achieved.

IGTP: A Next Point-of-Interest Recommendation Method that Integrates Geospatial and Temporal Preferences

2021 ◽  
Author(s):  
Xu Jiao ◽  
Yingyuan Xiao ◽  
Wenguang Zheng ◽  
Ke Zhu
Keyword(s):  
Rapid Development ◽  
Geographic Distance ◽  
Decision Making Process ◽  
Point Of Interest ◽  
Current Location ◽  
Poi Recommendation ◽  
Target User ◽  
Location Based Social Networks ◽  
The Individual ◽  
Temporal Preferences

Abstract With the rapid development of location-based social networks(LBSNs), point-of-interest(POI) recommendation has become an important way to meet the personalized needs of users. The purpose of POI recommendation is to provide personalized POI recommendation services for users. However, general POI recommendations cannot meet the individual needs of users. This is mainly because the decision-making process for users to choose POIs is very complicated and will be affected by various user contexts such as time, location, etc. This paper proposes a next POI recommendation method that integrates geospatial and temporal preferences, called IGTP. Compared with general POI recommendation, IGTP can provide more personalized recommendations for users according to their context information. First, IGTP uses users' preferences information to model users' check-in histories to effectively overcome the challenge of extremely sparse check-in data. Secondly, IGTP takes into account the geographic distance and density factors that affect people's choice of POIs, and limits POIs to be recommended to the potential activitive area centered on the current location of the target user. Finally, IGTP integrates geospatial and users' temporal preferences information into a unified recommendation process. Compared with six advanced baseline methods, the experimental results demonstrate that IGTP achieves much better performance.

scholarly journals Enzyme stabilization via computationally guided protein stapling

2017 ◽  
Vol 114 (47) ◽  
pp. 12472-12477 ◽  
Author(s):  
Eric J. Moore ◽  
Dmitri Zorine ◽  
William A. Hansen ◽  
Sagar D. Khare ◽  
Rudi Fasan
Keyword(s):  
Rapid Development ◽  
Catalytic Efficiency ◽  
Computational Design ◽  
Protein Stabilization ◽  
Superior Performance ◽  
Enzyme Stabilization ◽  
High Concentration ◽  
Chemical Denaturation ◽  
Organic Cosolvents ◽  
Catalytic Function

Thermostabilization represents a critical and often obligatory step toward enhancing the robustness of enzymes for organic synthesis and other applications. While directed evolution methods have provided valuable tools for this purpose, these protocols are laborious and time-consuming and typically require the accumulation of several mutations, potentially at the expense of catalytic function. Here, we report a minimally invasive strategy for enzyme stabilization that relies on the installation of genetically encoded, nonreducible covalent staples in a target protein scaffold using computational design. This methodology enables the rapid development of myoglobin-based cyclopropanation biocatalysts featuring dramatically enhanced thermostability (ΔTm = +18.0 °C and ΔT50 = +16.0 °C) as well as increased stability against chemical denaturation [ΔCm (GndHCl) = 0.53 M], without altering their catalytic efficiency and stereoselectivity properties. In addition, the stabilized variants offer superior performance and selectivity compared with the parent enzyme in the presence of a high concentration of organic cosolvents, enabling the more efficient cyclopropanation of a water-insoluble substrate. This work introduces and validates an approach for protein stabilization which should be applicable to a variety of other proteins and enzymes.

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