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Wyszukujesz frazę "Arrival" wg kryterium: Temat


Tytuł:
Performance comparison of ToA and TDoA based tracking in underwater multipath environments using bernoulli filter
Autorzy:
Gunes, Ahmet
Powiązania:
https://bibliotekanauki.pl/articles/32917889.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
underwater target tracking
bernoulli filter
Time-of-Arrival
Time-Difference-of-Arrival
underwater multipath propagation
Opis:
Underwater localization and tracking is a challenging problem and Time-of-Arrival and Time-Difference-of-Arrival approaches are commonly used. However, the performance difference between these approaches is not well understood or analysed adequately. There are some analytical studies for terrestrial applications with the assumption that the signal arrival times are not correlated. However, this assumption is not valid for underwater propagation. To present the distinct nature of the problem under the water, a high-fidelity simulation is required. In this study, Time-of-Arrival and Time-Difference-of-Arrival approaches are compared using a ray tracing based propagation model. Moreover, basic methods to mitigate the multipath propagation problem are also implemented for Bernoulli filters. Since the Bernoulli filter is a joint detection and tracking filter, the detection performance is also analysed. Comparisons are done for all combinations of filter and measurement approaches. The results can help to design underwater localization systems better suited to the needs.
Źródło:
Polish Maritime Research; 2023, 1; 135-144
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Formulation of the simple Markovian model using fractional calculus approach and its application to analysis of queue behavior of severe patients
Autorzy:
Dhar, Soma
Mahanta, Lipi B.
Das, Kishore Kumar
Powiązania:
https://bibliotekanauki.pl/articles/1359228.pdf
Data publikacji:
2019-04-25
Wydawca:
Główny Urząd Statystyczny
Tematy:
fractional order
arrival rate
patients
fractional calculus
Opis:
In this paper, we introduce a fractional order of a simple Markovian model where the arrival rate of the patient is Poisson, i.e. independent of the patient size. Fraction is obtained by replacing the first order time derivative in the difference differential equations which govern the probability law of the process with the Mittag-Leffler function. We derive the probability distribution of the number N(t) of patients suffering from severe disease at an arbitrary time t. We also obtain the mean size (number) of the patients suffering from severe disease waiting for service at any given time t, in the form of E ν 0.5,0.5 (t), for different fractional values of server activity status, ν = 1,0.95,0.90 and for arrival rates α = β = 0.5. A numerical example is also evaluated and analysed by using the simple Markovian model with the help of simulation techniques.
Źródło:
Statistics in Transition new series; 2019, 20, 1; 117-129
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of the Azimuth Angle of the Arrival Direction for an Ultrasonic Signal by Using Indirect Determination of the Phase Shift
Autorzy:
Kreczmer, Bogdan
Powiązania:
https://bibliotekanauki.pl/articles/177127.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
ultrasonic range finder
sonar
direction of arrival
Opis:
The paper presents and discusses a method of azimuth determination of ultrasonic echo arrival in air. The basis of the presented approach is the assumption that the received signal is a narrowband one. In this way, the direction of the signal arrival can be determined based on its phase shift using two receivers. When the distance between the receivers exceeds half of the wavelength of the received signal, a problem of ambiguity in determining the angle of arrival arises. To solve this, a method using multiple pairs of receivers was used. Its robustness and temperature dependence is analysed. The most import ant advantages of the presented approach are simplified computations and low hardware requirements. Experimental data made it possible to show that for strong echoes, the accuracy is higher than 0.5°. In the case of weak echos, it is reduced to about 2°. Because the method is based on phase shift measurement, the ultrasonic sonar that uses this method can be compact in size. Moreover, owing to the theoretical analysis, certain properties of the mutual location of the receivers were found and formally proved. They are crucial for determining proper receivers’ inter-distances.
Źródło:
Archives of Acoustics; 2019, 44, 3; 585-601
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lorentzian Operator for Angular Source Localization with Large Array
Autorzy:
Khmou, Y.
Safi, S.
Frikel, M.
Powiązania:
https://bibliotekanauki.pl/articles/308330.pdf
Data publikacji:
2015
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
array processing
Direction of Arrival
narrowband
operator
Opis:
Source localization problem consists of an ensemble of techniques that are used to obtain spatial information of present radiation in given medium of propagation, with a constraint of the antenna geometry and the characteristics of radiating sources. This condition gives multitude of cases to study, hence several methods were proposed in the literature. In this paper, a new algorithm for estimating the Direction of Arrival (DoA) of narrowband and far eld punctual sources is introduced. By exploiting the spectrum of covariance matrix of received data, the Lorentzian function on spectral matrix to lter the eigenvalues is applied. This ltering process eliminates the eigenvalues belonging to signal subspace. Parameters of Lorentz function are adjusted using rst and second statistics of eigenvalues. The algorithm requires the knowledge of minimum eigenvalue and is performing when the dimension of antenna is relatively large which is conrmed by several Monte Carlo simulations.
Źródło:
Journal of Telecommunications and Information Technology; 2015, 4; 98-105
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The synchrosqueezing method in bearing estimation of stationary signals for passive sonar with towed array
Autorzy:
Czarnecki, K.
Leśniak, W.
Powiązania:
https://bibliotekanauki.pl/articles/332264.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
reassignment method
time-frequency analysis
direction of arrival
Opis:
In this paper a novel method of the bearing estimation in a passive sonar system with a towed array is introduced. The classical approach of the bearing estimation based on the spatial spectrum is extended by using the synchrosqeezing method that is a part of the reassignment method introduced by Kodera et al. The usage of this method leads to the precise bearing estimation. The proposed method requires a relatively small amount of computation, because of possibility of using the FFT algorithm. Moreover, method immunity against AWGN is tested for a selected sonar array having regard to the direction of arrival and the signal frequency.
Źródło:
Hydroacoustics; 2015, 18; 41-46
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Passive hydroacoustic method of detection and tracking object moving on the sea surface and floating in the depth
Autorzy:
Szymczak, W.
Buszman, K.
Powiązania:
https://bibliotekanauki.pl/articles/332439.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
passive hydroacoustic
hydrophone array
direction of arrival calculation
Opis:
The main goal of the paper is to present passive, autonomous system to observe objects moving on the sea surface and floating in the depth prepared to work in very shallow water. Complete system will be described starting from hardware realization finalizing on configuration of sensors and presentation of algorithms implemented in prepared to this project software ( alarm types, setting parameters responsible for alarm generation etc.). Finally example of object detection will be presented concentrating on remotely operate vehicles ROV – seabotix and combustion motorboat. At a given point of discussion, stability of algorithms eliminating the occurrence of false alarms will be presented.
Źródło:
Hydroacoustics; 2017, 20; 173-178
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Accuracy evaluation of Ro-Ro and Ro-Pax ships arrival to the ports
Autorzy:
Paulauskas, V.
Paulauskas, D.
Powiązania:
https://bibliotekanauki.pl/articles/116347.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
port practices
Ro-Ro Ships
Ro-Pax Ships
ship arrival
accuracy evaluation
shipping lines
shipping companies
arrival to the ports
Opis:
Ro-Ro and Ro-Pax ships works on basis of regular schedule and try keep this schedule as accurate as possible. In same time difficulties during Ro-Ro and Ro-Pax ships voyages like bad weather conditions, waiting time to entry in to port, ship's failures and others, sometime request more time as it was planned initially. Ro-Ro and Ro-Pax ships arrivals in to port evaluation is important not only just for the Ro-Ro and Ro-Pax shipping lines planning but as well it is very important for passengers, transport units (trucks) and port terminals. In this Article are analyzed delay times of Ro-Ro and Ro-Pax ships arrival to port on basis of statistical data and used mathematical models for calculation of the arrival time pass.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2020, 14, 2; 397-399
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Azimuth angle determination for the arrival direction for an ultrasonic echo signal
Autorzy:
Kreczmer, B.
Powiązania:
https://bibliotekanauki.pl/articles/384597.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
ultrasonic range finder
sonar
direction of arrival
azimuth angle
Opis:
In the paper, an idea of a method of signal arrival direction estimation is presented. The influence of time error measurements on the usage of the method is described. An approach to the problem of an increase in the robustness of the method is proposed. The results of experiments are presented and discussed.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2017, 11, 2; 31-41
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-resolution Direction of Arrival Estimation Method Based on Sparse Arrays with Minimum Number of Elements
Autorzy:
Mohammed, Jafar Ramadhan
Powiązania:
https://bibliotekanauki.pl/articles/1839475.pdf
Data publikacji:
2021
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
compressed sensing
direction of arrival
DOA
estimation
sparse array
Opis:
Regular fully filled antenna arrays have been widely used in direction of arrival (DOA) estimation. However, practical implementation of these arrays is rather complex and their resolutions are limited to the beamwidth of the array pattern. Therefore, higher resolution and simpler methods are desirable. In this paper, the compressed sensing method is first applied to an initial fully filled array to randomly select the most prominent and effective elements which are used to form the sparse array. To keep the dimension of the sparse array equal to that of the fully filled array, the first and the last elements were excluded from the sparseness process. In addition, some constraints on the sparse spectrum are applied to increase estimation accuracy. The optimization problem is then solved iteratively using the iterative reweighted l1 norm. Finally, a simple searching algorithm is used to detect peaks in the spectrum solution that correspond to the directions of the arriving signals. Compared with the existing scanned beam methods, such as the minimum variance distortionless response (MVDR) technique, and with subspace approaches, such as multiple signal classification (MUSIC) and ESPIRT algorithms, the proposed sparse array method offers better performance even with a lower number of array elements and in severely noisy environments. Effectiveness of the proposed sparse array method is verified via computer simulations.
Źródło:
Journal of Telecommunications and Information Technology; 2021, 1; 8-14
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-resolution Direction of Arrival Estimation Method Based on Sparse Arrays with Minimum Number of Elements
Autorzy:
Mohammed, Jafar Ramadhan
Powiązania:
https://bibliotekanauki.pl/articles/1839489.pdf
Data publikacji:
2021
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
compressed sensing
direction of arrival
DOA
estimation
sparse array
Opis:
Regular fully filled antenna arrays have been widely used in direction of arrival (DOA) estimation. However, practical implementation of these arrays is rather complex and their resolutions are limited to the beamwidth of the array pattern. Therefore, higher resolution and simpler methods are desirable. In this paper, the compressed sensing method is first applied to an initial fully filled array to randomly select the most prominent and effective elements which are used to form the sparse array. To keep the dimension of the sparse array equal to that of the fully filled array, the first and the last elements were excluded from the sparseness process. In addition, some constraints on the sparse spectrum are applied to increase estimation accuracy. The optimization problem is then solved iteratively using the iterative reweighted l1 norm. Finally, a simple searching algorithm is used to detect peaks in the spectrum solution that correspond to the directions of the arriving signals. Compared with the existing scanned beam methods, such as the minimum variance distortionless response (MVDR) technique, and with subspace approaches, such as multiple signal classification (MUSIC) and ESPIRT algorithms, the proposed sparse array method offers better performance even with a lower number of array elements and in severely noisy environments. Effectiveness of the proposed sparse array method is verified via computer simulations.
Źródło:
Journal of Telecommunications and Information Technology; 2021, 1; 8-14
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DOA Estimation of Ultrasonic Signal by Indirect Phase Shift Determination
Autorzy:
Kreczmer, Bogdan
Powiązania:
https://bibliotekanauki.pl/articles/31339749.pdf
Data publikacji:
2024
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
direction of arrival
signal phase
sonar
ultrasonic range finder
Opis:
The paper presents the concept of the method of determining the direction of ultrasonic signal arrival, i.e., the azimuth and elevation angles. This method is an extension of the previous approach which was proposed to determine only the azimuth angle. The approach is based on the indirect phase determination. This makes it possible to tolerate spacing of receivers greater than half the wavelength of the received signal. At the same time, it provides increased measurement accuracy and reduced hardware requirements. To check the robustness of the method, simulations were carried out for the geometric arrangement of the receivers of the sonar module, for which the method was then implemented. This sonar module was used in the conducted experiments. The results of these simulations and experiments are included in the paper and discussed.
Źródło:
Archives of Acoustics; 2024, 49, 1; 107-120
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling customers’ impatience with discouraged arrival and retention of reneging
Autorzy:
Medhi, Pallabi
Powiązania:
https://bibliotekanauki.pl/articles/2100339.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
baulking
impatience
queuing
reneging
discouraged arrival
retention of reneging
Opis:
The paper presents stochastic modelling of a single server, finite buffer Markovian queueing system with discouraged arrivals, baulking, reneging, and retention of reneged customers. The Markov process is used to derive the steady-state solution of the model. Closed-form expressions using probability generating functions (PGFs) are derived and presented for both classical and novel performance measures. In addition, a sensitivity analysis is carried out to study the effect of the system parameters on performance measures. A numerical problem is also presented to demonstrate the derived results and some design aspects.
Źródło:
Operations Research and Decisions; 2021, 31, 3; 67--88
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Minimum Array Elements for Resolution of Several Direction of Arrival Estimation Methods in Various Noise-Level Environments
Autorzy:
El Ouargui, I.
Safi, S.
Frikel, M.
Powiązania:
https://bibliotekanauki.pl/articles/956990.pdf
Data publikacji:
2018
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
covariance matrix
direction of arrival
geolocation
resolution
noise
smart antenna
Opis:
The resolution of a Direction of Arrival (DOA) estimation algorithm is determined based on its capability to resolve two closely spaced signals. In this paper, authors present and discuss the minimum number of array elements needed for the resolution of nearby sources in several DOA estimation methods. In the real world, the informative signals are corrupted by Additive White Gaussian Noise (AWGN). Thus, a higher signal-to-noise ratio (SNR) offers a better resolution. Therefore, we show the performance of each method by applying the algorithms in different noise level environments.
Źródło:
Journal of Telecommunications and Information Technology; 2018, 2; 87-94
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative Study between Several Direction of Arrival Estimation Methods
Autorzy:
Khmou, Y.
Safi, S.
Frikel, M.
Powiązania:
https://bibliotekanauki.pl/articles/308017.pdf
Data publikacji:
2014
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
array processing
Direction of Arrival
geolocalization
propagation
smart antenna
spectral analysis
Opis:
In this paper a comparative study, restricted to one-dimensional stationary case, between several Direction of Arrival (DOA) estimation algorithms of narrowband signals is presented. The informative signals are corrupted by an Additive White Gaussian Noise (AWGN), to show the performance of each method by applying directly the algorithms without pre-processing techniques such as forward-backward averaging or spatial smoothing.
Źródło:
Journal of Telecommunications and Information Technology; 2014, 1; 41-48
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparative analysis of (s, Q) and (s, S) ordering policies in a queuing-inventory system with stock-dependent arrival and queue-dependent service process
Autorzy:
Sugapriya, Chandrasekaran
Nithya, Murugesan
Jeganathan, Kathirvel
Selvakumar, Subramanian
Harikrishnan, Thanushkodi
Powiązania:
https://bibliotekanauki.pl/articles/27315339.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
stock-dependent arrival
queue-dependent service
infinite waiting hall
ordering principles
Opis:
This article deals with a Markovian queuing-inventory system (MQIS) under the stochastic modeling technique. The arrival stream of this system is dependent on the present stock level at an instant. Meanwhile, the system focuses on reducing the waiting time of a unit by assuming a queue-dependent service policy (QDSP). The system consists of an infinite waiting hall to receive an arriving unit. The MQIS assumes that no unit of arrival is allowed when the stock level of the system is empty. The discussion of this MQIS runs over the two types of ordering principles named 1) (s, Q) 2) (s, S). According to both ordering principles, the assumed arrival and service patterns have been considered separately and classified as Model-I (M-I) and Model-II (M-II) respectively. The steady state of the system for both M-I and M-II is analysed and resolved under the Neuts matrix-geometric technique. The system performance measures of the system are also computed. The expected cost function of both M-I and M-II are constructed as well. Further, the necessary numerical illustrations are provided and distinguished for M-I and M-II to explore the proposed model. This paper finds the optimum ordering policy to execute the stock-dependent arrival and queue-dependent service strategies.
Źródło:
Operations Research and Decisions; 2023, 33, 2; 121--153
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł

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