The Impact of Multipath Information on Time-of-Arrival Estimation

The structural health monitoring (SHM) of critical structures is a complex task that involves the use of different sensors that are also aimed at the identification of the location of the impact point using ultrasonic sensors. For the evaluation of the impact position, reference is often made to the well-known triangulation method. This method requires the estimation of the differential time of arrival (DToA) and the group velocity of the Lamb waves propagating into a plate-like structure: the uncertainty of these two parameters is taken into consideration as main cause of localization error. The work proposes a simple laboratory procedure based on a set-up with a pair of sensors that are symmetrically placed with respect to the impact point, to estimate the uncertainty of the DToA and the propagation velocity estimates. According to a theoretical analysis of the error for the impact position, the experimental uncertainties of DToA and the propagation velocity are used to estimate the overall limit of the SHM system for the impact positioning. Because the error for the DToA estimate depends also on the adopted signal processing, three common methods are selected and compared: the threshold, the correlation method, and a likelihood algorithm. Finally, the analysis of the positioning error using multisensory configuration is reported as useful for the design of the SHM system.

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On the impact of time-of-departure knowledge on the accuracy of time-of-arrival localization

Computer Networks ◽

10.1016/j.comnet.2020.107285 ◽

2020 ◽

Vol 176 ◽

pp. 107285

Author(s):

Matija Rezar ◽

Fabio Ricciato

Keyword(s):

Time Of Arrival ◽

The Impact

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Influence of parameters and location of the tumble inlet porton air charging in the diesel cylinder

E3S Web of Conferences ◽

10.1051/e3sconf/201913501083 ◽

2019 ◽

Vol 135 ◽

pp. 01083 ◽

Cited By ~ 23

Author(s):

Besarion Meskhi ◽

Boris Golev ◽

Victor Efros ◽

Dmitriy Rudoy ◽

Anastasiya Olshevskaya ◽

...

Keyword(s):

Combustion Chamber ◽

Cross Section ◽

Individual Factors ◽

Time Of Arrival ◽

Intake Valve ◽

Working Cycle ◽

Dynamic Loadings ◽

Diesel Cylinder ◽

The Impact ◽

Fresh Charge

The calculation of the actual working cycle processes allows to determine with satisfactory accuracy the value of the main parameters of the newly developed engine for any given conditions of its operation, to assess the impact of individual factors on the processes and the performance of the cycle as a whole. Thus establish character of change of pressure and temperature in each process, define the sizes of the engine, and also solve questions of increase of its reliability taking into account the received settlement thermal and dynamic loadings. Pre-intake begins at the time of opening the inlet and ends at the time of arrival of the piston in the TDC. The mixture or air does not enter the cylinder during preheating, as the volume of the cylinder decreases. However, the pre-opening of the intake valve allows you to create a sufficient cross-section to the beginning of the receipt of fresh charge in the cylinder and, therefore, leads to an improvement in the filling of the cylinders. In addition, due to the delay in closing the exhaust valve, the purge of the combustion chamber from residual gases is improved.

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Exploring Passengers’ Travel Behaviors Based on Elaboration Likelihood Model under the Impact of Intelligent Bus Information

Journal of Advanced Transportation ◽

10.1155/2019/9095279 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Fan Wu ◽

Xiaowei Hu ◽

Shi An ◽

Duo Zhang

Keyword(s):

Travel Time ◽

Significant Influence ◽

Choice Behavior ◽

Elaboration Likelihood Model ◽

Elaboration Likelihood ◽

Time Of Arrival ◽

Road Congestion ◽

Likelihood Model ◽

Types Of Information ◽

The Impact

The ubiquitous intelligent transportation infrastructure in metropolitan cities has enabled bus passengers to access comprehensive (even real-time) bus information. However, the impact of different types of information on passenger behavior is still insufficiently understood. Combining with the theory of information processing path, this study partially fills this gap by adopting an elaboration likelihood model (ELM) suitable for explaining how the various types of intelligent bus information influence passengers’ choice behavior. Six types of intelligent bus information (information of bus lines, estimated travel time, estimated time of arrival, congestion inside bus, road congestion, and bus fare) are used as six independent variables, and passengers’ departure time, travel routes, and travel modes as dependent variables. Valid questionnaire assessments were collected from 285 participants at 4 bus stops equipped with intelligent bus system in Harbin, providing quantitative data to verify each hypothesis. The results show that six types of intelligent bus information to different degrees (significant influence, slight influence, and no significant influence) affect three types of passengers’ choice behaviors; the information of estimated travel time and that of road congestion are both significantly effective in all three types of choice behavior while bus fare has no significant influence. Meanwhile, other types of information have a significant or slight effect on certain behavior. The results of this study can be used to design more reasonable intelligent bus information provision strategies to meet passengers’ requirements.

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Scenario-based numerical modelling and the palaeo-historic record of tsunamis in Wallis and Futuna, Southwest Pacific

Natural Hazards and Earth System Sciences Discussions ◽

10.5194/nhessd-3-2283-2015 ◽

2015 ◽

Vol 3 (4) ◽

pp. 2283-2346 ◽

Cited By ~ 1

Author(s):

G. Lamarche ◽

S. Popinet ◽

B. Pelletier ◽

J. Mountjoy ◽

J. Goff ◽

...

Keyword(s):

Numerical Models ◽

Plate Boundary ◽

South Pacific ◽

Tsunami Hazard ◽

Time Of Arrival ◽

Barrier Reef ◽

Outer Reef ◽

Southwest Pacific ◽

The North ◽

The Impact

Abstract. We investigated the tsunami hazard in the remote French territory of Wallis and Futuna, Southwest Pacific, using the Gerris flow solver to produce numerical models of tsunami generation, propagation and inundation. Wallis consists of the inhabited volcanic island of Uvéa that is surrounded by a lagoon delimited by a barrier reef. Futuna and the island of Alofi forms the Horn Archipelago located ca. 240 km east of Wallis. They are surrounded by a narrow fringing reef. Futuna and Alofi emerge from the North Fiji Transform Fault that marks the seismically active Pacific-Australia plate boundary. We generated fifteen tsunami scenarios. For each, we calculated maximum wave elevation (MWE), inundation distance, and Expected Time of Arrival (ETA). The tsunami sources were local, regional and distant earthquake faults located along the Pacific Rim. In Wallis, the outer reef may experience 6.8 m-high MWE. Uvéa is protected by the barrier reef and the lagoon, but inundation depths of 2–3 m occur in several coastal areas. In Futuna, flow depths exceeding 2 m are modelled in several populated areas, and have been confirmed by a post-September 2009 South Pacific tsunami survey. The channel between the islands of Futuna and Alofi amplified the 2009 tsunami, which resulted in inundation distance of almost 100 m and MWE of 4.4 m. This first-ever tsunami hazard modelling study of Wallis and Futuna compares well with palaeotsunamis recognised on both islands and observation of the impact of the 2009 South Pacific tsunami. The study provides evidence for the mitigating effect of barrier and fringing reefs from tsunamis.

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Minimization of aircraft fuel consumption subjected to arrival time constraint

Aircraft Engineering and Aerospace Technology ◽

10.1108/aeat-01-2020-0023 ◽

2020 ◽

Vol 92 (7) ◽

pp. 1063-1072

Author(s):

Muhaned Gilani ◽

Durmuş Sinan Körpe

Keyword(s):

Fuel Consumption ◽

Operating Cost ◽

Time Constraints ◽

Programming Algorithm ◽

Time Of Arrival ◽

Content Type ◽

Design Variables ◽

Aircraft Fuel ◽

Optimum Speed ◽

The Impact

Purpose This paper aims to minimize aircraft fuel consumption during the cruise phase when the flight is subjected to a specific time of arrival for different weights and distances. Design/methodology/approach The approach adopted herein uses sequential quadratic programming algorithm from MATLAB optimization toolbox, which includes a mathematical model of a jet airliner based on the Base of Aircraft Data as a function evaluator, to find out the impact of meet-time of arrival constraints on fuel consumption. The cruising speeds at predefined segments and the altitude are defined as the design variables. Findings The algorithm determines the optimum cruise altitudes and speeds for minimum fuel consumption in the case of no time constraints, also, for different time constraints where the flight time shall be reduced by increasing speed and lowering the altitude in most of the investigated cases. Practical implications The algorithm computes the optimum speed and the altitude according to different flight scenarios with the meet-time of arrival constraints for minimum fuel consumption which affects the direct operating cost of the flight. The algorithm might greatly help in decision-making for the meet-time of arrival operations. Originality/value Developing an algorithm to optimize the speed and the altitude of an aircraft based on weight and range for minimization of fuel consumption. It is a pioneer study in the literature that deals with the effect of meet-time constraints on fuel consumption.

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Spatial and Temporal Variation of Wideband Indoor Channels

International Journal of Antennas and Propagation ◽

10.1155/2010/735434 ◽

2010 ◽

Vol 2010 ◽

pp. 1-11 ◽

Cited By ~ 6

Author(s):

David L. Ndzi ◽

Nick Savage ◽

Boris Gremont

Keyword(s):

Impulse Response ◽

Transfer Functions ◽

Temporal Variations ◽

Spatial And Temporal Variation ◽

Small Scale ◽

Time Of Arrival ◽

Prony Algorithm ◽

Detailed Assessment ◽

Value Decomposition ◽

The Impact

Extensive studies of the impact of temporal variations induced by people on the characteristics of indoor wideband channels are reported. Singular Value Decomposition Prony algorithm has been used to compute the impulse response from measured channel transfer functions. The high multipath resolution of the algorithm has allowed a detailed assessment of the shapes of individual multipath clusters and their variation in time and space in indoor channels. Large- and small-scale analyses show that there is a significant dependency of the channel response on room size. The presence of people in the channel has been found to induce both signal enhancements and fading with short-term dynamic variations of up to 30 dB, depending on the number of people and their positions within the room. A joint amplitude and time of arrival model has been used to successfully model measured impulse response clusters.

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Robust Identification of Strain Waves due to Low-Velocity Impact with Different Impactor Stiffness

Sensors ◽

10.3390/s19061283 ◽

2019 ◽

Vol 19 (6) ◽

pp. 1283 ◽

Cited By ~ 1

Author(s):

Alessio Beligni ◽

Claudio Sbarufatti ◽

Andrea Gilioli ◽

Francesco Cadini ◽

Marco Giglio

Keyword(s):

Sensor Networks ◽

Low Velocity Impact ◽

Time Of Arrival ◽

Low Velocity ◽

Metallic Structures ◽

Robust Identification ◽

Impact Monitoring ◽

Multiple Impact ◽

Processing Techniques ◽

The Impact

Low-velocity impacts represent a major concern for aeronautical structures, sometimes producing barely detectable damage that could severely hamper the aircraft safety, even with regards to metallic structures. For this reason, the development of an automated impact monitoring system is desired. From a passive monitoring perspective, any impact generates a strain wave that can be acquired using sensor networks; signal processing techniques allow for extracting features useful for impact identification, possibly in an automatic way. However, impact wave characteristics are related to the impactor stiffness; this presents a problem for the evaluation of an impact-related feature and for the development of an automatic approach to impact identification. This work discusses the problem of reducing the influence of the impactor stiffness on one of the features typically characterizing the impact event, i.e., the time of arrival (TOA). Two passive sensor networks composed of accelerometers and piezoelectric sensors are installed on two metallic specimens, consisting of an aluminum skin and a sandwich panel, with aluminum skins and NOMEXTM honeycomb core. The effect of different impactor stiffnesses is investigated by resorting to an impact hammer, equipped with different tips. Subsequently, a method for data processing is defined to obtain a feature insensitive to the impactor stiffness, and this method is applied to multiple impact signals for feature uncertainty evaluation.

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