Agoraphilic navigation algorithm in dynamic environment with obstacles motion tracking and prediction

Robotica ◽  
2021 ◽  
pp. 1-19
Author(s):  
H. S. Hewawasam ◽  
M. Yousef Ibrahim ◽  
Gayan Kahandawa ◽  
T. A. Choudhury
Keyword(s):  
Free Space ◽  
Motion Tracking ◽  
Dynamic Environment ◽  
Experimental Tests ◽  
Cluttered Environments ◽  
Navigation Algorithm ◽  
Prediction Module ◽  
Future Space ◽  
Free Spaces ◽  
Advanced Development

Abstract This paper presents a new algorithm to navigate robots in dynamically cluttered environments. The proposed algorithm uses basic concepts of space attraction (hence the term Agoraphilic) to navigate robots through dynamic obstacles. The new algorithm in this paper is an advanced development of the original Agoraphilic navigation algorithm that was only able to navigate robots in static environments. The Agoraphilic algorithm does not look for obstacles (problems) to avoid but rather for a free space (solutions) to follow. Therefore, it is also described as an optimistic navigation algorithm. This algorithm uses only one attractive force created by the available free space. The free-space concept allows the Agoraphilic algorithm to overcome inherited challenges of general navigation algorithms. However, the original Agoraphilic algorithm has the limitation in navigating robots only in static, not in dynamic environments. The presented algorithm was developed to address this limitation of the original Agoraphilic algorithm. The new algorithm uses a developed object tracking module to identify the time-varying free spaces by tracking moving obstacles. The capacity of the algorithm was further strengthened by the new prediction module. Future space prediction allowed the algorithm to make decisions considering future growing/diminishing free spaces. This paper also includes a bench-marking study of the new algorithm compared with a recently published APF-based algorithm under a similar operating environment. Furthermore, the algorithm was validated based on experimental tests and simulation tests.

scholarly journals Lipschitz-free Spaces on Finite Metric Spaces

2019 ◽  
Vol 72 (3) ◽  
pp. 774-804 ◽  
Author(s):  
Stephen J. Dilworth ◽  
Denka Kutzarova ◽  
Mikhail I. Ostrovskii
Keyword(s):  
Metric Space ◽  
Free Space ◽  
Metric Spaces ◽  
Large Classes ◽  
Complemented Subspace ◽  
Finite Metric Space ◽  
Free Spaces ◽  
Finite Metric Spaces

AbstractMain results of the paper are as follows:(1) For any finite metric space $M$ the Lipschitz-free space on $M$ contains a large well-complemented subspace that is close to $\ell _{1}^{n}$.(2) Lipschitz-free spaces on large classes of recursively defined sequences of graphs are not uniformly isomorphic to $\ell _{1}^{n}$ of the corresponding dimensions. These classes contain well-known families of diamond graphs and Laakso graphs.Interesting features of our approach are: (a) We consider averages over groups of cycle-preserving bijections of edge sets of graphs that are not necessarily graph automorphisms. (b) In the case of such recursive families of graphs as Laakso graphs, we use the well-known approach of Grünbaum (1960) and Rudin (1962) for estimating projection constants in the case where invariant projections are not unique.

An Enhanced Multi-GNSS Navigation Algorithm by Utilising a Priori Inter-System Biases

2017 ◽  
Vol 71 (2) ◽  
pp. 339-351 ◽  
Author(s):  
Zhounan Dong ◽  
Changsheng Cai ◽  
Rock Santerre ◽  
Cuilin Kuang
Keyword(s):  
Moving Average ◽  
A Priori ◽  
Three Dimensional ◽  
Main Idea ◽  
Experimental Tests ◽  
Satellite Observation ◽  
Satellite System ◽  
Estimation Algorithms ◽  
Navigation Algorithm ◽  
Sky Conditions

The integration of multi-constellation Global Navigation Satellite System (GNSS) measurements can effectively improve the accuracy and reliability of navigation and positioning solutions, while the Inter-System Bias (ISB) is a key issue for compatibility. The ISB is traditionally estimated as an unknown parameter along with three-dimensional position coordinates and a receiver clock offset with respect to Global Positioning System (GPS) time. ISB estimation of this sort will sacrifice a satellite observation for each integrated GNSS system. These sacrificed observations could be vital in situations of limited satellite visibility. In this study, an enhanced multi-GNSS navigation algorithm is developed to avoid sacrificing observations under poor visibility conditions. The main idea of this algorithm is to employ a moving average filter to smooth the ISBs estimated at previous epochs. The filtered value is utilised as a priori information at the current epoch. Experimental tests were conducted to evaluate the enhanced algorithm under open and blocked sky conditions. The results show that the enhanced algorithm effectively improves the accuracy and availability of navigation solutions under the blocked sky condition, with performance being comparable to traditional ISB estimation algorithms in open sky conditions. The improvement rates of the three-dimensional position accuracy and availability reach up to 63% and 21% in the blocked sky environment. Even in the case of only four different GNSS satellites, a position solution can still be obtained using the enhanced algorithm.

Transmitter with quantum cascade laser for free space optics communication system

2011 ◽  
Vol 59 (4) ◽  
pp. 419-423 ◽  
Author(s):  
M. Gutowska ◽  
D. Pierścińska ◽  
M. Nowakowski ◽  
K. Pierściński ◽  
D. Szabra ◽  
...  
Keyword(s):  
Quantum Cascade Laser ◽  
Communication System ◽  
Free Space ◽  
Open Space ◽  
Spectral Characteristics ◽  
Average Power ◽  
Experimental Tests ◽  
Free Space Optics ◽  
Quantum Cascade ◽  
Space Optics

Transmitter with quantum cascade laser for free space optics communication system The paper presents results of experimental tests of the quantum cascade laser from Alpes Lasers company in terms of its application in the optic communication system in an open space. The measurements involved the current - voltage characteristics while measuring also the average power of emitted radiation, and spectral characteristics for different temperatures and different laser pulse durations. The duration of laser pulses was matched to parameters used in telecommunication interfaces. The construction of the transmitter module which uses the tested laser is also presented.

scholarly journals SLA-Based Sharing Economy Service with Smart Contract for Resource Integrity in the Internet of Things

2019 ◽  
Vol 9 (17) ◽  
pp. 3602 ◽  
Author(s):  
Lei Hang ◽  
Do-Hyeun Kim
Keyword(s):  
Performance Metrics ◽  
Service Level Agreement ◽  
Dynamic Environment ◽  
Experimental Tests ◽  
Service Level ◽  
Sharing Economy ◽  
Third Party ◽  
Blockchain Technology ◽  
Smart Contract ◽  
Trading Partners

Recently, technology startups have leveraged the potential of blockchain-based technologies to govern institutions or interpersonal trust by enforcing signed treaties among different individuals in a decentralized environment. However, it is going to be hard enough convincing that the blockchain technology could completely replace the trust among trading partners in the sharing economy as sharing services always operate in a highly dynamic environment. With the rapid expanding of the rental market, the sharing economy faces more and more severe challenges in the form of regulatory uncertainty and concerns about abuses. This paper proposes an enhanced decentralized sharing economy service using the service level agreement (SLA), which documents the services the provider will furnish and defines the service standards the provider is obligated to meet. The SLA specifications are defined as the smart contract, which facilitates multi-user collaboration and automates the process with no involvement of the third party. To demonstrate the usability of the proposed solution in the sharing economy, a notebook sharing case study is implemented using the Hyperledger Fabric. The functionalities of the smart contract are tested using the Hyperledger Composer. Moreover, the efficiency of the designed approach is demonstrated through a series of experimental tests using different performance metrics.

Research on Rotating Modulated Strap-Down Inertial Navigation System Based on Micro-Electro-Mechanical Systems (MEMS) Sensors (RMSINS)

2011 ◽  
Vol 148-149 ◽  
pp. 192-197 ◽  
Author(s):  
Tao Xu ◽  
Bin Wang ◽  
Xue Yun Wang
Keyword(s):  
Navigation System ◽  
Inertial Navigation System ◽  
Mechanical Systems ◽  
Inertial Navigation ◽  
Mems Sensors ◽  
Micro Electro Mechanical Systems ◽  
Navigation Algorithm ◽  
Improving Accuracy ◽  
Performance Results ◽  
Advanced Development

Advanced development of an Inertial Navigation System (INS) using rotating modulated technique based on Micro-Electro-Mechanical Systems (MEMS) sensors is described. The system architecture and the mechanical structure are detailed. Alignment and navigation algorithms apposite to the RMSINS system are derived. Preliminary system static navigation experiment results are presented. Performance results show that rotating modulated technology, with appropriate navigation algorithm, makes it possible to use the MEMS sensors in SINS system, with the benefit of reducing system costs as well as improving accuracy.

scholarly journals FREE SPACE AS AN ELEMENT OF OPEN-AIR MUSEUMS’ EXHIBITION

2021 ◽  
pp. 23-35
Author(s):  
Mariia Brych
Keyword(s):  
Urban Planning ◽  
Free Space ◽  
Cultural Landscapes ◽  
Spatial Configuration ◽  
Material Structure ◽  
Heritage Preservation ◽  
Space Organization ◽  
Free Spaces ◽  
Characteristic Features ◽  
Industrial Landscapes

In the area of architectural heritage preservation, the leveling of monument objects’ environment is an important problem. The essence of the monuments is laid not only in their material structure but also in a historically formed environment and spatial configuration that exhibits their historical and cultural content, enriches artistic properties. Open-air museums are specific institutions that are characterized by the use of not only monumental volumes and structures but also the free space between them. Cultural landscapes - lands of estates and residences, parks in palace ensembles, territories of monastic complexes, industrial landscapes, memorial places, and archaeological complexes become elements of the exhibition. Features of exhibition space organization in open-air museums are not sufficiently highlighted in scientific literature. Depending on the selected exhibition concept, a set of activities of the museum is determined and the museum zoning occurs. The use of free spaces is divided into two levels depending on the scale – urban planning and architectural. The urban planning level is responsible for the environmental design of the overall space of the ensemble or the complex of monuments. The architectural level of open-air museum formation envisages the organization of existing buildings, structures, and areas between them. On the urban-planning level, it is important to ensure the convenience of the visual perception of the complex: to reveal the most interesting fragments of the environment and visual connections, to emphasize the basic aesthetic, associative, symbolic, and practical properties of cultural landscapes within the open-air museum. On the architectural level of organization, free spaces become the basis for many activities - various educational, cultural, and entertainment events. Free space in museums serves as an exhibit, an element of activity processes and various events, and also serves as a basic tool for detecting and emphasizing the characteristic features of exhibited complexes and ensembles.  

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