Temat: multipath - Prolib Integro

Skocz do pozycji: 1.

Autorzy:: Gawłowicz, Piotr
Kamisiński, Andrzej
Rząsa, Jacek
Rzym, Grzegorz
Wójcik, Robert
Stankiewicz, Rafał
Domżał, Jerzy
Jurkiewicz, Piotr
Wajda, Krzysztof
Duliński, Zbigniew
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

Artykuł

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Skocz do pozycji: 2.

Tytuł:: Effects of Multipath and Conventional NMES on Maximum Comfortable Stimulus and Torque Production
Autorzy:: Bremner, Cody B.
Holcomb, William R.
Tematy:: NMES
multipath
quadriceps; Pokaż więcej
Wydawca:: Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Powiązania:: https://bibliotekanauki.pl/articles/1030629.pdf Link otwiera się w nowym oknie
Opis:: A novel multipath NMES (m-NMES) device has shown improved outcomes relative to conventional NMES (c-NMES) during recent basic and training studies. However, the mechanisms by which m-NMES outperformed c-NMES remain unclear. This study aimed to better understand these mechanisms by comparing the effects of m-NMES and c-NMES on maximum comfortable stimulus intensity and the subsequent NMES-induced torque, as these variables ultimately impact NMES training intensity; which is considered to be the primary determinant of NMES effectiveness. We measured maximum comfortable stimulus intensity and the subsequent NMES-induced torque while participants performed NMES-induced contractions under two conditions (m-NMES and c-NMES). Maximum comfortable stimulus intensity was significantly greater under the m-NMES condition, but the subsequent NMES-induced torque was not significantly different across conditions. m-NMES does not appear to influence the outcomes in a clinically meaningful manner, since it performed similarly to c-NMES with respect to peak NMES-induced torque.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Intra- and inter-cell interference investigations for broadband radio access systems above 10 GHz
Autorzy:: Bose, R.
Hayn, A.
Jakoby, R.
Tematy:: multipath propagation
interchannel interference; Pokaż więcej
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/308404.pdf Link otwiera się w nowym oknie
Opis:: Local multipoint distribution systems (LMDS) operating above 10 GHz have a large bandwidth (2-3 GHz) but a very limited range. These systems can provide coverage to a few kilometers only. These systems can provide coverage to a few kilometers only. The size of the macro cells illuminated by the base stations, where line of sight (LOS) exists, is 1 to 6 km. To provide coverage to customers where LOS is not possible, repeaters or passive reflectors may be used. In this paper we present first results of reflection measurements at 42 GHz, and based on that, simple multipath studies, taking into account the beamwidth of the antennas of both, transmitter and receiver. Secondly, LOS cochannel and adjacent channel interference are assessed for cellular LMDS networks. As suggested in the CRABS report, the maximal spectral efficiency can be obtained with a dual frequency and polarization reuse plan. This frequency and polarization reuse leads to interference. In this paper we have first calculated the cochannel interference (CCI) and the adjacent channel interference (ACI) due to the frequency/polarization reuse schemes suggested in the CRABS report. The effects of the variation of the half power beam width (HPBW) of the receiver, the time precentage parameter p, and the cell radius on C/I are also reported. In the latter part of the paper we propose a simple interference reduction technique based on re-orientation of the receiver antennas. We have also explored the possibility of using trellis coded modulation (TCM) for reducing interference levels. Initial results have been found to be quite encouraging.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: A survey on methods to provide multipath transmission in wired packet networks
Autorzy:: Rząsa, Jacek
Wójcik, Robert
Stankiewicz, Rafał
Kantor, Mirosław
Domżał, Jerzy
Wajda, Krzysztof
Duliński, Zbigniew
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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na półce

Skocz do pozycji: 5.

Tytuł:: Edge decompositions of multigraphs into multi-2-paths
Autorzy:: Kratochvil, J.
Lonc, Z.
Meszka, M.
Skupień, Z.
Tematy:: edge decomposition
multigraph
multipath
path
time complexity; Pokaż więcej
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:: https://bibliotekanauki.pl/articles/2050185.pdf Link otwiera się w nowym oknie
Opis:: We establish the computational time complexity of the existence problem of a decomposition of an instance multigraph into isomorphic 3-vertex paths with multiple edges. If the two edge multiplicities are distinct, the problem is NPC; if mutually equal then polynomial.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Spectral analysis of multi-year GNSS code multipath time-series
Autorzy:: Kudrys, Jacek
Tematy:: GNSS
code multipath
spectral analysis
spectral index; Pokaż więcej
Wydawca:: Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Powiązania:: https://bibliotekanauki.pl/articles/390405.pdf Link otwiera się w nowym oknie
Opis:: In the presented study multi-year time series of changes in the L1 pseudo-range multipath are analysed. Data from 8 stations of the EUREF Permanent Network (EPN) were used in the study. Periodic components present in the signal and their stability over time were analysed. Also, the type of background noise was determined, based on the spectral index. In some cases, the presence of weak components with a 1/2 and 1/3 of the Chandler period has also been found. Time-frequency analysis shows that periodic signals are not stationary in most of the examined cases, and particular signal components occur only temporarily. The analysed signals were char-acterised by pink noise in the lower frequency range and by white noise for higher frequencies, which is also characteristic for time series of coordinates obtained from GNSS measurements.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Empirical Seasons Fadings in Radio Communication at 6 GHz Band
Autorzy:: Bogucki, J.
Wielowieyska, E.
Tematy:: line-of-sight radio links
multipath
propagation; Pokaż więcej
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/308892.pdf Link otwiera się w nowym oknie
Opis:: This paper covers unavailability of line-of-sight radio links due to multipath propagation. Multipath fading in the atmosphere is not permanent phenomenon. The five year investigation results of the received radio signal fading in the radio links and their season empirical distributions are presented.
Dostawca treści:: Biblioteka Nauki

Artykuł

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Skocz do pozycji: 8.

Tytuł:: Fading duration in line-of-sight radio links at 6 GHz
Autorzy:: Bogucki, J.
Wielowieyska, E.
Tematy:: fading
line-of-sight radio links
multipath
propagation; Pokaż więcej
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/308731.pdf Link otwiera się w nowym oknie
Opis:: Broadband fixed wireless access, local multipoint distribution service networks are promising wireless solutions to connect fixed users to the backbone network instead of wired copper or fiber optic networks, via point-to-multipoint cellular networks. Channel capacity is of primary importance in broadband fixed wireless access networks due to increasing demand for multimedia services and possibility of providing wireless internet. Modern radio transmission systems are specifically designed for meeting two main objectives: to provide a solution for long distance networks with high transmission capacity, and to guarantee the highest link quality. Availability of a radio-relay system is very important and dependent on many factors, particularly propagation conditions in the troposphere. The article describes wave propagation that determines the performance of a radio-relay path at 6 GHz. Attenuation of received signal level measured in this frequency range depends on propagation condition on terrestrial path. Examples of measured fading duration of are presented.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Impacts of forest spatial structure on variation of the multipath phenomenon of navigation satellite signals
Autorzy:: Brach, Michał
Stereńczak, Krzysztof
Bolibok, Leszek
Kwaśny, Łukasz
Krok, Grzegorz
Laszkowski, Michał
Tematy:: GNSS
multipath
random forest
Borut
forest structure
LiDAR; Pokaż więcej
Wydawca:: Instytut Badawczy Leśnictwa
Powiązania:: https://bibliotekanauki.pl/articles/2044153.pdf Link otwiera się w nowym oknie
Opis:: The GNSS (Global Navigation Satellite System) receivers are commonly used in forest management in order to determine objects coordinates, area or length assessment and many other tasks which need accurate positioning. Unfortunately, the forest structure strongly limits access to satellite signals, which makes the positioning accuracy much weak comparing to the open areas. The main reason for this issue is the multipath phenomenon of satellite signal. It causes radio waves reflections from surrounding obstacles so the signal do not reach directly to the GNSS receiver’s antenna. Around 50% of error in GNSS positioning in the forest is because of multipath effect. In this research study, an attempt was made to quantify the forest stand features that may influence the multipath variability. The ground truth data was collected in six Forest Districts located in different part of Poland. The total amount of data was processed for over 2,700 study inventory plots with performed GNSS measurements. On every plot over 25 forest metrics were calculated and over 25 minutes of raw GNSS observations (1500 epochs) were captured. The main goal of this study was to find the way of multipath quantification and search the relationship between multipath variability and forest structure. It was reported that forest stand merchantable volume is the most important factor which influence the multipath phenomenon. Even though the similar geodetic class GNSS receivers were used it was observed significant difference of multipath values in similar conditions.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 10.

Tytuł:: Impacts of forest spatial structure on variation of the multipath phenomenon of navigation satellite signals
Autorzy:: Brach, Michał
Laszkowski, Michał
Bolibok, Leszek
Stereńczak, Krzysztof
Kwaśny, Łukasz
Krok, Grzegorz
Wydawca:: The Committee on Forestry Sciences and Wood Technology of the Polish Academy of Sciences and the Forest Research Institute in Sekocin Stary
Cytata wydawnicza:: Brach, Michał & Stereńczak, Krzysztof & Bolibok, Leszek & Kwaśny, Łukasz & Krok, Grzegorz & Laszkowski, Michał. (2019). Impacts of forest spatial structure on variation of the multipath phenomenon of navigation satellite signals. Folia Forestalia Polonica, Series A. 51. 3-21. 10.2478/ffp-2019-0001.
Opis:: The GNSS (Global Navigation Satellite System) receivers are commonly used in forest management in order to determine objects coordinates, area or length assessment and many other tasks which need accurate positioning. Unfortunately, the forest structure strongly limits access to satellite signals, which makes the positioning accuracy much weak comparing to the open areas. The main reason for this issue is the multipath phenomenon of satellite signal. It causes radio waves reflections from surrounding obstacles so the signal do not reach directly to the GNSS receiver’s antenna. Around 50% of error in GNSS positioning in the forest is because of multipath effect. In this research study, an attempt was made to quantify the forest stand features that may influence the multipath variability. The ground truth data was collected in six Forest Districts located in different part of Poland. The total amount of data was processed for over 2,700 study inventory plots with performed GNSS measurements. On every plot over 25 forest metrics were calculated and over 25 minutes of raw GNSS observations (1500 epochs) were captured. The main goal of this study was to find the way of multipath quantification and search the relationship between multipath variability and forest structure. It was reported that forest stand merchantable volume is the most important factor which influence the multipath phenomenon. Even though the similar geodetic class GNSS receivers were used it was observed significant difference of multipath values in similar conditions.
Dostawca treści:: Repozytorium Centrum Otwartej Nauki

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