The next generation of IGS ROTI Maps: an extension toward global coverage

2020 ◽  
Author(s):  
Andrzej Krankowski ◽  
Iurii Cherniak ◽  
Irina Zakharenkova ◽  
Adam Fron ◽  
Kacper Kotulak
Keyword(s):  
Northern Hemisphere ◽  
Space Weather ◽  
Ionospheric Irregularities ◽  
Next Generation ◽  
Dual Frequency ◽  
Case Scenario ◽  
Worst Case ◽  
Plasma Irregularities ◽  
Low Latitudes ◽  
Global Coverage

<p>The International GNSS Service (IGS) has accepted for official release a new ionospheric product for specification of ionospheric irregularities occurrence and intensity over the Northern Hemisphere as derived from multi-site ground-based GPS observations. Initially, we focused on the Northern Hemisphere auroral and midlatitude regions because of the highest concentration of the GNSS users and user supporting permanent networks located within the American, European, and Asian sectors. The IGS ROTI maps product is routinely generated by multi-step processing of carrier phase delays in dual-frequency GPS signals and transferred to the IGS CDDIS database. Now, ROTI maps allow regular monitoring of ionospheric irregularities over the Northern Hemisphere and provide information about past events when strong ionospheric irregularities developed here.</p><p>Obviously, the plasma irregularities that occur at high, middle, and low latitudes have different physical mechanisms of their origin and development. For study of the climatological features of ionospheric irregularities occurrence, investigation of the ionospheric responses for Space Weather drivers, processes derived from below, this actual ROTI Map product is required to cover low latitudes and the Southern hemisphere polar and midlatitudes.</p><p>During last decade, numerous ground-based permanent receivers were deployed within the global and regional networks and these observations are publicly available. These data can support our activity toward extending the current IGS ROTI maps product for a global coverage. In this paper, we present initial results of ROTI maps product performance to characterize ionospheric irregularities exited by different types of geophysical processes and space weather events. The next generation of the IGS ROTI maps product can be a valuable tool for global ionospheric irregularities monitoring and retrospective analysis of plasma irregularities impact on the GNSS positioning in the “worst case scenario” domain.</p><p>The research is supported by the National Science Centre, Poland, through grants 2017/25/B/ST10/00479 and 2017/27/B/ST10/02190 and <strong>t</strong>he National Centre for Research and Development, Poland, through grant DWM/PL-CHN/97/2019</p><p><strong> </strong></p><p>Keywords: GPS, ionosphere, ionospheric irregularities, ROTI, IGS</p>

scholarly journals The space weather station at the University of Alcala

2021 ◽  
Author(s):  
Antonio Guerrero ◽  
Consuelo Cid ◽  
Alberto García ◽  
Emilio Domínguez ◽  
Fernando Montoya ◽  
...  
Keyword(s):  
Undergraduate Students ◽  
Space Weather ◽  
Low Frequency ◽  
Decision Makers ◽  
Weather Station ◽  
Geomagnetic Disturbances ◽  
Case Scenario ◽  
Worst Case ◽  
The University ◽  
Low Frequency Waves

The Space Weather station at the University of Alcala (UAH-STA) is a place for instrumentation that is able to produce useful products and services in a worst case scenario, assuring decision-makers the access to the data and consequently, increasing the confidence to take actions. The current development consists of an antenna to monitor ionospheric disturbances through the reception of very low frequency waves and a magnetometer to indicate the geomagnetic disturbances caused by sources external to the Earth. This work shows the development of both instruments and some examples of ionospheric and geomagnetic events recorded by both of them. This project serves also as a successful story of using space weather as a teaching tool due to the involvement of undergraduate students at final stage of industrial and telecommunication engineering.

Equatorial Ionospheric Irregularities Observed by COSMIC 2 and GOLD Missions

2021 ◽  
Author(s):  
Qian Wu ◽  
John Braun ◽  
William Schreiner ◽  
Sergey Sokolovskiy ◽  
Iurii Cherniak ◽  
...  
Keyword(s):  
Space Weather ◽  
Communication Systems ◽  
Back Propagation ◽  
Ionospheric Irregularities ◽  
Plasma Bubbles ◽  
Weather Phenomenon ◽  
Low Latitudes

<p>Equatorial ionospheric irregularities is an important space weather phenomenon, which can disrupt GNSS and communication systems. COSMIC 2 GNSS RO observations are affected via scintillations in signal amplitudes and phases. At the same time, we can use these scintillations to monitor and geolocate the ionospheric irregularities, which are of great value to the space weather services. Geolocation of the irregularities based on the RO signals is difficult, as any irregularities along the line between the GNSS and RO satellite can cause scintillation. Several geolocation methods are known. A back propagation (BP) method to geolocate the irregularities originally developed in 2001 and applied for GPS/MET RO data is being modified and applied for COSMIC 2 scintillation data. Because the equatorial irregularities are often associated with plasma bubbles, which are visible to the NASA UV imager GOLD, we have been using the GOLD images to validate the BP geolocation method.    In this presentation, we will show the progress of recent validation effort of the BP geolocation method by comparing the COSMIC 2 geolocated irregularities with plasma bubbles in GOLD UV observations. Though, GOLD observations are only available in the American sector, COSMIC 2 observations can be used geolocate ionospheric irregularities throughout the equatorial and low latitudes</p>

Design and investigation of N1-class next-generation passive optical network-2 (NG-PON2) coexistence architecture in the presence of Kerr effect and four-wave mixing (FWM) for fiber to the home (FTTX) access networks

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Rajendraprasad A. Pagare ◽  
Santosh Kumar ◽  
Abhilasha Mishra
Keyword(s):  
Wavelength Division Multiplexing ◽  
Phase Modulation ◽  
Optical Network ◽  
Single Mode ◽  
Four Wave Mixing ◽  
Passive Optical Network ◽  
Wave Mixing ◽  
Next Generation ◽  
Case Scenario ◽  
Worst Case

Abstract In this paper, we investigated N1-class Time and Wavelength Division Multiplexing (TWDM) Next-Generation Passive Optical Network-2 (NG-PON2) supporting symmetric and coexistence configuration in a worst-case scenario. The network is optimized in the presence of linear and nonlinear impairments such as chromatic dispersion (CD), self-phase modulation (SPM), cross-phase modulation (XPM), and four-wave mixing (FWM). On-off key (OOK) modulation technique incorporating hybrid optical distribution network (ODN) i.e., wavelength select (WS) and wavelength-routed (WR) ODN is used to connect downstream (D/S) and upstream (U/S) channels supporting symmetric 80 Gbps data rate operating at 2.5/2.5 and 10/10 Gbps, respectively. G.652 single-mode (SM) fiber channel is modeled for fiber launch power PTODN = 3 dBm and 4 dBm for D/S and U/S channels to implement N1-class network. The D/S and U/S receiver sensitivity (Rxs) demonstrated are −44.23/−37.46 dBm and −28.46/−35.32 dBm and inter-channel crosstalk (Cc) is −31.97/−31.39 dB accommodating 640 splitter configuration at 50 km in the presence of impairments at 10E-7 bit error rate (BER) and Quality (Q)-factor of 5 for 10 Gbps channel.

scholarly journals Climatology of GPS signal loss observed by Swarm satellites

2018 ◽  
Vol 36 (2) ◽  
pp. 679-693 ◽  
Author(s):  
Chao Xiong ◽  
Claudia Stolle ◽  
Jaeheung Park
Keyword(s):  
High Latitude ◽  
Ionospheric Plasma ◽  
Ionospheric Irregularities ◽  
Signal Loss ◽  
Radio Science ◽  
Plasma Irregularities ◽  
Gps Satellites ◽  
Swarm Satellites ◽  
Low Latitudes ◽  
December Solstice

Abstract. By using 3-year global positioning system (GPS) measurements from December 2013 to November 2016, we provide in this study a detailed survey on the climatology of the GPS signal loss of Swarm onboard receivers. Our results show that the GPS signal losses prefer to occur at both low latitudes between ±5 and ±20∘ magnetic latitude (MLAT) and high latitudes above 60∘ MLAT in both hemispheres. These events at all latitudes are observed mainly during equinoxes and December solstice months, while totally absent during June solstice months. At low latitudes the GPS signal losses are caused by the equatorial plasma irregularities shortly after sunset, and at high latitude they are also highly related to the large density gradients associated with ionospheric irregularities. Additionally, the high-latitude events are more often observed in the Southern Hemisphere, occurring mainly at the cusp region and along nightside auroral latitudes. The signal losses mainly happen for those GPS rays with elevation angles less than 20∘, and more commonly occur when the line of sight between GPS and Swarm satellites is aligned with the shell structure of plasma irregularities. Our results also confirm that the capability of the Swarm receiver has been improved after the bandwidth of the phase-locked loop (PLL) widened, but the updates cannot radically avoid the interruption in tracking GPS satellites caused by the ionospheric plasma irregularities. Additionally, after the PLL bandwidth increased larger than 0.5 Hz, some unexpected signal losses are observed even at middle latitudes, which are not related to the ionospheric plasma irregularities. Our results suggest that rather than 1.0 Hz, a PLL bandwidth of 0.5 Hz is a more suitable value for the Swarm receiver. Keywords. Ionosphere (equatorial ionosphere; ionospheric irregularities) – radio science (radio wave propagation)

Reducing Probabilistic Weather Forecasts to the Worst Case Scenario: Anchoring Effects

2008 ◽  
Author(s):  
Sonia Savelli ◽  
Susan Joslyn ◽  
Limor Nadav-Greenberg ◽  
Queena Chen
Keyword(s):  
Case Scenario ◽  
Worst Case ◽  
Weather Forecasts ◽  
Worst Case Scenario ◽  
Anchoring Effects

EXPEDITION TO MALI, 2020

2020 ◽  
pp. 12-28
Author(s):  
D. V. Vaniukova ◽  
◽  
P. A. Kutsenkov ◽  
Keyword(s):  
Mass Murder ◽  
The State ◽  
Case Scenario ◽  
Worst Case ◽  
Traditional Art ◽  
Peter The Great ◽  
State Museum ◽  
Bobo Dioulasso ◽  
Oriental Studies ◽  
The Village

The research expedition of the Institute of Oriental studies of the Russian Academy of Sciences has been working in Mali since 2015. Since 2017, it has been attended by employees of the State Museum of the East. The task of the expedition is to study the transformation of traditional Dogon culture in the context of globalization, as well as to collect ethnographic information (life, customs, features of the traditional social and political structure); to collect oral historical legends; to study the history, existence, and transformation of artistic tradition in the villages of the Dogon Country in modern conditions; collecting items of Ethnography and art to add to the collection of the African collection of the. Peter the Great Museum (Kunstkamera, Saint Petersburg) and the State Museum of Oriental Arts (Moscow). The plan of the expedition in January 2020 included additional items, namely, the study of the functioning of the antique market in Mali (the “path” of things from villages to cities, which is important for attributing works of traditional art). The geography of our research was significantly expanded to the regions of Sikasso and Koulikoro in Mali, as well as to the city of Bobo-Dioulasso and its surroundings in Burkina Faso, which is related to the study of migrations to the Bandiagara Highlands. In addition, the plan of the expedition included organization of a photo exhibition in the Museum of the village of Endé and some educational projects. Unfortunately, after the mass murder in March 2019 in the village of Ogossogou-Pel, where more than one hundred and seventy people were killed, events in the Dogon Country began to develop in the worst-case scenario: The incessant provocations after that revived the old feud between the Pel (Fulbe) pastoralists and the Dogon farmers. So far, this hostility and mutual distrust has not yet developed into a full-scale ethnic conflict, but, unfortunately, such a development now seems quite likely.

Risk-Based Robust Bidding Strategies for EVs’ Aggregators in Day-ahead Markets with Uncertainty

2020 ◽  
Author(s):  
Ahmed Abdelmoaty ◽  
Wessam Mesbah ◽  
Mohammad A. M. Abdel-Aal ◽  
Ali T. Alawami
Keyword(s):  
Robust Optimization ◽  
Electricity Market ◽  
Real Life ◽  
Optimization Approach ◽  
Case Scenario ◽  
Worst Case ◽  
Bidding Strategies ◽  
Wind Generators ◽  
Proposed Model ◽  
Optimal Bidding

In the recent electricity market framework, the profit of the generation companies depends on the decision of the operator on the schedule of its units, the energy price, and the optimal bidding strategies. Due to the expanded integration of uncertain renewable generators which is highly intermittent such as wind plants, the coordination with other facilities to mitigate the risks of imbalances is mandatory. Accordingly, coordination of wind generators with the evolutionary Electric Vehicles (EVs) is expected to boost the performance of the grid. In this paper, we propose a robust optimization approach for the coordination between the wind-thermal generators and the EVs in a virtual<br>power plant (VPP) environment. The objective of maximizing the profit of the VPP Operator (VPPO) is studied. The optimal bidding strategy of the VPPO in the day-ahead market under uncertainties of wind power, energy<br>prices, imbalance prices, and demand is obtained for the worst case scenario. A case study is conducted to assess the e?effectiveness of the proposed model in terms of the VPPO's profit. A comparison between the proposed model and the scenario-based optimization was introduced. Our results confirmed that, although the conservative behavior of the worst-case robust optimization model, it helps the decision maker from the fluctuations of the uncertain parameters involved in the production and bidding processes. In addition, robust optimization is a more tractable problem and does not suffer from<br>the high computation burden associated with scenario-based stochastic programming. This makes it more practical for real-life scenarios.<br>

scholarly journals A Thermally Conductive Pt/AAO Catalyst for Hydrogen Passive Autocatalytic Recombination

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 491
Author(s):  
Alina E. Kozhukhova ◽  
Stephanus P. du Preez ◽  
Aleksander A. Malakhov ◽  
Dmitri G. Bessarabov
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Combustion Temperature ◽  
Volume Fraction ◽  
Morphological Characteristics ◽  
Al Alloy ◽  
Impregnation Method ◽  
Case Scenario ◽  
Worst Case ◽  
Thermal Distribution

In this study, a Pt/anodized aluminum oxide (AAO) catalyst was prepared by the anodization of an Al alloy (Al6082, 97.5% Al), followed by the incorporation of Pt via an incipient wet impregnation method. Then, the Pt/AAO catalyst was evaluated for autocatalytic hydrogen recombination. The Pt/AAO catalyst’s morphological characteristics were determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The average Pt particle size was determined to be 3.0 ± 0.6 nm. This Pt/AAO catalyst was tested for the combustion of lean hydrogen (0.5–4 vol% H2 in the air) in a recombiner section testing station. The thermal distribution throughout the catalytic surface was investigated at 3 vol% hydrogen (H2) using an infrared camera. The Al/AAO system had a high thermal conductivity, which prevents the formation of hotspots (areas where localized surface temperature is higher than an average temperature across the entire catalyst surface). In turn, the Pt stability was enhanced during catalytic hydrogen combustion (CHC). A temperature gradient over 70 mm of the Pt/AAO catalyst was 23 °C and 42 °C for catalysts with uniform and nonuniform (worst-case scenario) Pt distributions. The commercial computational fluid dynamics (CFD) code STAR-CCM+ was used to compare the experimentally observed and numerically simulated thermal distribution of the Pt/AAO catalyst. The effect of the initial H2 volume fraction on the combustion temperature and conversion of H2 was investigated. The activation energy for CHC on the Pt/AAO catalyst was 19.2 kJ/mol. Prolonged CHC was performed to assess the durability (reactive metal stability and catalytic activity) of the Pt/AAO catalyst. A stable combustion temperature of 162.8 ± 8.0 °C was maintained over 530 h of CHC. To confirm that Pt aggregation was avoided, the Pt particle size and distribution were determined by TEM before and after prolonged CHC.

scholarly journals A Comparison of Match Demands Using Ball-in-Play versus Whole Match Data in Professional Soccer Players of the English Championship

Sports ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 76
Author(s):  
Dylan Mernagh ◽  
Anthony Weldon ◽  
Josh Wass ◽  
John Phillips ◽  
Nimai Parmar ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Soccer Players ◽  
Training Methods ◽  
Case Scenario ◽  
Worst Case ◽  
Repeated Measures Design ◽  
Worst Case Scenario ◽  
Professional Soccer ◽  
Peak Match ◽  
Playing Time

This is the first study to report the whole match, ball-in-play (BiP), ball-out-of-play (BoP), and Max BiP (worst case scenario phases of play) demands of professional soccer players competing in the English Championship. Effective playing time per soccer game is typically <60 min. When the ball is out of play, players spend time repositioning themselves, which is likely less physically demanding. Consequently, reporting whole match demands may under-report the physical requirements of soccer players. Twenty professional soccer players, categorized by position (defenders, midfielders, and forwards), participated in this study. A repeated measures design was used to collect Global Positioning System (GPS) data over eight professional soccer matches in the English Championship. Data were divided into whole match and BiP data, and BiP data were further sub-divided into different time points (30–60 s, 60–90 s, and >90 s), providing peak match demands. Whole match demands recorded were compared to BiP and Max BiP, with BiP data excluding all match stoppages, providing a more precise analysis of match demands. Whole match metrics were significantly lower than BiP metrics (p < 0.05), and Max BiP for 30–60 s was significantly higher than periods between 60–90 s and >90 s. No significant differences were found between positions. BiP analysis allows for a more accurate representation of the game and physical demands imposed on professional soccer players. Through having a clearer understanding of maximum game demands in professional soccer, practitioners can design more specific training methods to better prepare players for worst case scenario passages of play.

scholarly journals Trissolcus japonicus (Hymenoptera: Scelionidae) Causes Low Levels of Parasitism in Three North American Pentatomids Under Field Conditions

2019 ◽  
Vol 19 (4) ◽  
Author(s):  
Joshua M Milnes ◽  
Elizabeth H Beers
Keyword(s):  
North American ◽  
Native Species ◽  
Classical Biological Control ◽  
The United States ◽  
Host Finding ◽  
Pest Species ◽  
Case Scenario ◽  
Worst Case ◽  
Egg Masses ◽  
Trissolcus Japonicus

Abstract Trissolcus japonicus (Ashmead), an Asian parasitoid of Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), was first detected in North America in 2014. Although testing in quarantine facilities as a candidate for classical biological control is ongoing, adventive populations have appeared in multiple sites in the United States, Canada, and Europe. Extensive laboratory testing of T. japonicus against other North American pentatomids and H. halys has revealed a higher rate of parasitism of H. halys, but not complete host specificity. However, laboratory tests are necessarily artificial, in which many host finding and acceptance cues may be circumvented. We offered sentinel egg masses of three native pentatomid (Hemiptera: Pentatomidae) pest species (Chinavia hilaris (Say), Euschistus conspersus Uhler, and Chlorochroa ligata (Say)) in a field paired-host assay in an area with a well-established adventive population of T. japonicus near Vancouver, WA. Overall, 67% of the H. halys egg masses were parasitized by T. japonicus during the 2-yr study. Despite the ‘worst case’ scenario for a field test (close proximity of the paired egg masses), the rate of parasitism (% eggs producing adult wasps) on all three native species was significantly less (0.4–8%) than that on H. halys eggs (77%). The levels of successful parasitism of T. japonicus of the three species are C. hilaris > E. conspersus > C. ligata. The potential impact of T. japonicus on these pentatomids is probably minimal.

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