Satellite Location Research Articles

Prediction of Soft Proton Intensities in the Near-Earth Space Using Machine Learning

Abstract The spatial distribution of energetic protons contributes to the understanding of magnetospheric dynamics. Based upon 17 yr of the Cluster/RAPID observations, we have derived machine-learning-based models to predict the proton intensities at energies from 28 to 962 keV in the 3D terrestrial magnetosphere at radial distances between 6 and 22 RE. We used the satellite location and indices for solar, solar wind, and geomagnetic activity as predictors. The results demonstrate that the neural network (multi-layer perceptron regressor) outperforms baseline models based on the k-nearest neighbors and historical binning on average by ∼80% and ∼33%, respectively. The average correlation between the observed and predicted data is about 56%, which is reasonable in light of the complex dynamics of fast-moving energetic protons in the magnetosphere. In addition to a quantitative analysis of the prediction results, we also investigate parameter importance in our model. The most decisive parameters for predicting proton intensities are related to the location—Z geocentric solar ecliptic direction—and the radial distance. Among the activity indices, the solar wind dynamic pressure is the most important. The results have a direct practical application, for instance, for assessing the contamination particle background in the X-ray telescopes for X-ray astronomy orbiting above the radiation belts. To foster reproducible research and to enable the community to build upon our work we publish our complete code, the data, and the weights of trained models. Further description can be found in the GitHub project at https://github.com/Tanveer81/deep_horizon.

The Organization of Pericentromeric Heterochromatin in Polytene Chromosome 3 of the Drosophilamelanogaster Line with the Rif11; SuURES Su(var)3-906 Mutations Suppressing Underreplication.

Although heterochromatin makes up 40% of the Drosophila melanogaster genome, its organization remains little explored, especially in polytene chromosomes, as it is virtually not represented in them due to underreplication. Two all-new approaches were used in this work: (i) with the use of a newly synthesized Drosophila line that carries three mutations, Rif11, SuURES and Su(var)3-906, suppressing the underreplication of heterochromatic regions, we obtained their fullest representation in polytene chromosomes and described their structure; (ii) 20 DNA fragments with known positions on the physical map as well as molecular genetic features of the genome (gene density, histone marks, heterochromatin proteins, origin recognition complex proteins, replication timing sites and satellite DNAs) were mapped in the newly polytenized heterochromatin using FISH and bioinformatics data. The borders of the heterochromatic regions and variations in their positions on arm 3L have been determined for the first time. The newly polytenized heterochromatic material exhibits two main types of morphology: a banding pattern (locations of genes and short satellites) and reticular chromatin (locations of large blocks of satellite DNA). The locations of the banding and reticular polytene heterochromatin was determined on the physical map.

A Location Management Strategy for Satellite Internet Constellation

Satellites are currently the most effective means to achieve seamless global coverage of the Internet. Due to the frequent beam switching caused by the high-speed movement of satellites, it is too expensive to directly apply the location management strategy in the terrestrial network to the satellite Internet constellation (SIC). To build a web browsing platform based on satellite Internet, it is necessary to display the location of satellites and terminals in real time. For this reason, this paper proposes the location management strategy of SIC. It uses the characteristics of large and periodic satellite beam coverage in a certain period of time, redesigns the location management database structure, location registration mechanism and call delivery mechanism, and analyses and simulates the bit cost of location management. The result proves that compared with the traditional strategy, this strategy greatly reduces the cost of SIC.

Euler's three-body problem

In physics and astronomy, Euler's three-body problem is to solve for the motion of a body that is acted upon by the gravitational field of two other bodies. This problem is named after Leonhard Euler (1707-1783), who discussed it in memoirs published in the 1760s. In these publications, Euler found that the parameter that controls the relative distances among three collinear bodies is given by a quintic equation. Later on, in 1772, Lagrange dealt with the same problem, and demonstrated that for any three masses with circular orbits, there are two special constant-pattern solutions, one where the three bodies remain collinear, and the other where the bodies occupy the vertices of two equilateral triangles. Because of their importance, these five points became known as Lagrange points. The quintic equation found by Euler for the relative distances among the collinear bodies was also found later by Lagrange, and because of that, Euler has also been given credit for the discovery of the three collinear Lagrange points. A practical application of the collinear points for satellite location is also presented.

Headache infusion centers: A survey on treatments provided, infusion center operations, and barriers to developing new infusion centers.

Infusion therapy refers to the intravenous administration of medicines and fluids for the treatment of status migrainosus, severe persistent headaches, or chronic headache. Headache practices and centers offer this treatment for patients as an alternative to the emergency department (ED) setting. However, little information is available in the literature on understanding the operations of an infusion center. We sought to survey the Inpatient Headache & Emergency Medicine specialty section and the Academic Program Directors listserv of the American Headache Society (AHS) to better understand current practices. A survey was advertised and distributed to the listservs of both the Inpatient Headache & Emergency Medicine specialty section and the Academic Program Directors, which combined included both academic and private practices. In addition, the survey was available on laptops at related events at an annual AHS meeting in Scottsdale. Of the 127members of the combined group of both listservs, 50 responded with an overall survey response rate of 39%. Ten out of fifty were from programs with more than one responder completing the survey, leaving 40 unique headache programs. Academic programs made up the majority of programs (85%, 34/40). The total of 40 participating programs is comparable with the 47 academic headache programs listed on the American Migraine Foundation website at the time of the survey. Of the academic programs surveyed, most were hospital based (n=23) compared with a satellite location (n=11). Of all programs surveyed, 68% (27/40) offered infusion therapy. Of those that did not have an infusion practice (n=13), the most common reason cited was insufficient staffing (n=8). Key highlights of the survey included the following: The majority of programs offering infusions obtain prior authorization before scheduling (70%, 19/27) and offer patient availability 5days/week (78%, 21/27) typically only during business hours (81%, 22/27). Programs reported that they typically give three to four medications during each infusion session (72%, 18/25). Treatment paradigms varied between programs. Programs surveyed were concentrated in the Northeast and Midwest regions of the United States. The limited number of headache infusion centers overall may contribute to the limited ability of headache infusion centers to prevent ED migraine visits. Headache patients can have unpredictable headache onset, and most of the infusion practices surveyed appeared to adapt to this by offering infusions most days during a work week. However, this need for multiple days per week may also explain the most common reason for not having an infusion practice, which is insufficient staffing. Various treatment paradigms are implemented by different practitioners, and future studies will have to focus on investigation of best practice.

Stochastic Geometry-Based Analysis of LEO Satellite Communication Systems

This letter studies the performance of a low-earth-orbit (LEO) satellite communication system where the locations of the LEO satellites are modeled as a binomial point process (BPP) on a spherical surface. In particular, we study the user coverage probability for a scenario where satellite gateways (GWs) are deployed on the ground to act as a relay between the users and the LEO satellites. We use tools from stochastic geometry to derive the coverage probability for the described setup assuming that LEO satellites are placed at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n$ </tex-math></inline-formula> different altitudes, given that the number of satellites at each altitude <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$a_{k}$ </tex-math></inline-formula> is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N_{k}$ </tex-math></inline-formula> where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\leq k\leq n$ </tex-math></inline-formula> . To resemble practical scenarios where satellite communication can play an important role in coverage enhancement, we compare the performance of the considered setup with a scenario where the users are solely covered by a fiber-connected base station (referred to as anchored base station or ABS in the rest of the letter) at a relatively far distance, which is a common challenge in rural and remote areas. Using numerical results, we show the performance gain, in terms of coverage probability, at rural and remote areas when LEO satellite communication systems are adopted. Finally, we draw multiple system-level insights regarding the density of GWs required to outperform the ABS, as well as the number of LEO satellites and their altitudes.

Cytogenetics of wild species of the Alstroemeriaceae family (Liliales)

Studies on cytogenetic diversity within the Alstroemeriaceae family along its intercontinental distribution are scarce when comparing species of their four genera. This study aimed at exploring the cytogenetic diversity of the family along their geographical distribution, including species that inhabit Oceania and South America. Using quantitative and qualitative methods, we analysed 50 species of the four genera (24% of the species of the family), comparing cytogenetic characters such as chromosome number, karyotype morphology and asymmetry, location of chromosome satellites, total haploid length, meiotic behaviour, C and FISH banding, and DNA C-values. We concur with other authors in that generic delimitation based on chromosome number is clear among Alstroemeria (2n = 16) and Bomarea (2n = 18), both belonging to Alstroemerioideae. Moreover, these two genera have different chromosome numbers compared to those of Luzuriaga and Drymophila (both 2n = 20) belonging to Luzuriagoideae. The above observations were also supported by the phylogeny reconstructed here. In addition, analyses on karyotype morphology and asymmetry have determined gradual differences in nuclear architecture among genera and species. We concluded that the cytogenetic diversity described within Alstroemeriaceae is concentrated mainly in South America, which is to be expected given the higher species diversity that has been described for that continent. Although the presence of three chromosome numbers within Alstroemeriaceae has no relation with their wide geographical distribution in two continents, an appreciable variation was observed in karyotype morphology and asymmetry, total haploid length and cytomolecular features when the species were compared along their geographical range.

Laser Intersatellite Links in a Starlink Constellation: A Classification and Analysis

Laser intersatellite links (LISLs) are envisioned between satellites in upcoming satellite constellations, such as the one in phase I of SpaceX's Starlink. Within a constellation, satellites can establish LISLs with other satellites in the same orbital plane (OP) or in different OPs. We present a classification of LISLs based on the location of satellites within a constellation and of LISLs' duration. Then, using the satellite constellation for phase I of Starlink, we study the effect that varying a satellite's LISL range has on the number of different types of LISLs it can establish with other satellites. In addition to permanent LISLs, we observe a significant number of temporary LISLs between satellites in crossing OPs. Such LISLs can play a vital role in achieving low-latency paths within next-generation optical wireless satellite networks.

Improved Analysis of STEVE Photographs

AbstractWe present a new approach for the analysis of high‐resolution digital camera photographs taken by photographers who have fortuitous been able to capture rare events, such as the glowing sky phenomenon known as strong thermal emission velocity enhancement (STEVE). This method is especially effective with a time lapse series of images of the night sky taken under constant camera settings with a steady pointing. Stars, planets, and satellites seen in such images can be used to determine the precise and accurate registration of camera pixels to coordinates of angular altitude and azimuth. The location of satellites in the image enables precise and accurate synchronization of the images. We apply these techniques to the series of photographs of STEVE taken on July 25, 2016. We confirm the altitude structure previously found for STEVE. We find it most likely that the green picket fence features often seen during STEVE events are produced by auroral electron precipitation. With the precipitation assumption, we are able to extract novel information about the energy spectrum of the particles responsible for the production of STEVE luminosity in this particular event. Similarly, analyses of archived digital photographs may constitute a treasure trove of important data for improved understanding of rare and transient events, such as STEVE.

Ku-Band Low Noise Block Converter (LNB) Sync Application Design Using Android Based Solid Dish

Mobile phone users, especially the Android version of the smartphone, are increasingly spoiling their users. It is undeniable that users do not know their age, even many children have an Android version of the smartphone to play with. Meanwhile, in the satellite tracking world, the satellite tracking is still using TV when tracking the satellite so that it feels difficult. ApplicationLow Noise Block Converter is a video view application from a receiver to an Android smartphone that was built to make it easier for tracking satellites to track one of the satellites that you want to lock. This application also includes satellite tracking information facilities such as tracking guides, frequency updates, and satellite location. ApplicationLow Noise Block Converterbuilt with the Android Studio application using the Java programming language. With the creation of the applicationLow Noise Block Converter seas a new alternative to replace TV as a satellite tracking device or monitoring tool.

Spatial distribution of mangrove using a geographic information system in Aceh Besar

The mangrove forest ecosystem is unique, both because of the subtract of siltation which results in less soil abrasion, high soil salinity, and experiencing a cycle of inundation by tides. Only a few plant species survive in such a place, and most of these species are unique to mangroves because they have undergone a process of adaptation and evolution. It is not widely known how far the mangrove areas are spread in Aceh. Therefore, research needs to be carried out with the aim of knowing the extent of the sustainability of mangrove management in terms of sediment characteristics. Information about the distribution, area and change of mangrove land cover can be determined by spatial analysis using a Geographical Information System (GIS) using ArcGIS. The method used in this research is the transect method and analysed based on the identification of mangrove species. Based on the analysis of the results of the study, it was identified that the mangrove species found in the research location of Peukan Bada sub-district (West Aceh Besar) consit of Rhizopora mucronata and Sonneratia alba, while the mangrove species found in Baitussalam (north Aceh Besar) were Rhizopora mucronata and Sonneratia alba. Meanwhile, based on observations with satellite imagery and location surveys, it was found that the mangroves in Baitussalam sub-district were denser and spread evenly than in the Peukan Bada area.

Космічна інфраструктура інтернету речей. Стан та перспективи розвитку

We present an overview of possibilities for existing Satellite Communication Systems utilization to provide Internet of Things Services. It is shown that existing Satellite Communication Systems provide traffic transmission for IoT Systems with Cloud Architecture. The proposals are explicated on the possibility of using Fog and Edge Computing for Satellite Communication Systems. The implementation of Fog and Edge computing in IoT Systems requires the modernization of the Low-Earth Orbit (LEO) and Geostationary Orbit (GEO) Satellite Communication Systems, and we show the ways of their enhancement. To increase the efficiency of IoT data processing and the reliability of IoT Data Storage, we propose to construct an Orbital Cloud Data Storage in GEO, which consists of several GEO Satellites - Cloud Computing Data Centers. Such a structure would require the development of methods of access providing to the Orbital Cloud Data Storage. For these purposes, our propositions include using GEO High-Throughput Satellites and satellites from the structure of LEO Satellite Communication. The issues of interaction between Orbital Cloud Data Storage and ground-based Cloud Data Processing and Storage Infrastructure are briefly considered. The orbital slots in GEO are proposed for the location of GEO Satellites - Cloud Computing Data Centers.

Moving the emergency department of a big tertiary center to a satellite lo-cation, during the COVID-19 crisis period: Operational risks and their mitigation

Moving the emergency department of a big tertiary center to a satellite lo-cation, during the COVID-19 crisis period: Operational risks and their mitigation

MMS Observations of Narrow-Band Quasi-Parallel Whistler Waves in the Flow Braking Region in Near-Earth Magnetotail

This paper presents an analysis of wave activity recorded by the MMS satellites during a prolonged dipolarization in the near magnetotail (XGSM ~ –17 RE). It was found that multiple narrow-band, quasi-parallel whistler wave bursts were observed behind the leading front of dipolarization, during the phase of growth of the magnetic field’s BZ component. The durations of wave bursts were ~1–15 s, and the characteristic frequencies ranged from ~0.1 to 0.8 fc (fc is the electron gyrofrequency). Based on a detailed analysis of a single wave burst, it was found that the frequency corresponding to the maximum value of a linear increment of quasi-parallel whistler waves was close in magnitude to the observed frequency, which indicates the possibility of satellite location close to the source of waves. We also demonstrated that, in the case under discussion, the electrons with pitch angles of 125°–135° and energies of ~3–12 keV made a largest contribution to the increment of whistler waves. These observations have shown that, during dipolarizations, the thermal and suprathermal electron populations are most effectively involved in resonant interaction with whistler waves.

Fault-tolerant estimation of satellite orbital states

This paper is devoted to global positioning system (GPS)-based fault-tolerant satellite orbital states estimation which is used for the pseudo-ranging model. GPS is widely used by many researchers to determine the orbit state vectors of satellites, but errors in GPS measurements can cause major errors in satellite location detection. Therefore, there is a need for an architecture that will resist possible measurement errors and GPS malfunctions. This study aims to present the novel approaches to tolerate the errors that may take place in GPS measurements. The satellite localisation has been detected via a pseudo-ranging model between four GPS satellites and the target satellite. The Keplerian equations and orbit elements are used for the satellite dynamic model with orbital J2 perturbation which is due to the flattened shape of the earth is taken into account via the extended Kalman filter (EKF) algorithms. The reconfigurable and the adaptive version of fault-tolerant localisation architecture eliminate the GPS measurement errors during estimating satellite position vectors. The comparison of the prediction architectures of the fault tolerant satellite state vectors originally proposed. At the same time, it is possible to use fault tolerant architectures designed to detect whether GPS satellites are malfunctioning or not.

PRINCIPLES OF GNSS

The most direct method for obtaining spatial information in digital form is the use of data from Polish geodetic measurements obtained from the global satellite location identification system. Global location systems GNSS belong to non-photographic recording systems of the group of remote methods for Earth measurements. The most popular system is GPS (Global Positioning System), designed and controlled by the US Department of Defense.

The “INNOVARE” Project: Innovative Plants for Distributed Poly-Generation by Residual Biomass

The valorization of residual biomass plays today a decisive role in the concept of “circular economy”, according to which each waste material must be reused to its maximum extent. The collection and energy valorization at the local level of biomass from forest management practices and wildfire prevention cutting can be settled in protected areas to contribute to local decarbonization, by removing power generation from fossil fuels. Despite the evident advantages of bioenergy systems, several problems still hinder their diffusion, such as the need to assure their reliability by extending the operating range with materials of different origin. The Italian project “INNOVARE—Innovative plants for distributed poly-generation by residual biomass”, funded by the Italian Ministry of Economic Development (MISE), has the main scope of improving micro-cogeneration technologies fueled by biomass. A micro-combined heat and power (mCHP) unit was chosen as a case study to discuss pros and cons of biomass-powered cogeneration within a national park, especially due to its flexibility of use. The availability of local biomasses (woodchips, olive milling residuals) was established by studying the agro-industrial production and by identifying forest areas to be properly managed through an approach using a satellite location system based on the microwave technology. A detailed synergic numerical and experimental characterization of the selected cogeneration system was performed in order to identify its main inefficiencies. Improvements of its operation were optimized by acting on the engine control strategy and by also adding a post-treatment system on the engine exhaust gas line. Overall, the electrical output was increased by up to 6% using the correct spark timing, and pollutant emissions were reduced well below the limits allowed by legislation by working with a lean mixture and by adopting an oxidizing catalyst. Finally, the global efficiency of the system increased from 45.8% to 63.2%. The right blending of different biomasses led to an important improvement of the reliability of the entire plant despite using an agrifood residual, such as olive pomace. It was demonstrated that the use of this biomass is feasible if its maximum mass percentage in a wood matrix mixture does not exceed 25%. The project was concluded with a real operation demonstration within a national park in Southern Italy by replacing a diesel genset with the analyzed and improved biomass-powered plant and by proving a decisive improvement of air quality in the real environment during exercise.

Two-Echelon Dispatching Problem With Mobile Satellites in City Logistics

At present, city logistics mostly adopts a two-echelon dispatching model which combines distribution centers located in suburbs and fixed satellites located in urban areas for distribution. However, both expensive rental fees and daily changes of customer demand in metropolitan areas make dispatching route generated by fixed satellites inefficient. Moreover, the existing mobile depot model needs a large investment for facilities. In this paper, we propose a two-echelon city dispatching model with mobile satellites (2ECD-MS) which locations of mobile satellites change according to demands of customers to ensure the efficiency of delivery routes in every day. A cluster-based variable neighborhood search scheduling algorithm is proposed to determine locations of mobile satellites and dispatching routes of trucks and tricycles. Then, the 2ECD-MS is extended to 2ECD-MS-TDD to allow trucks dispatching directly (TDD) for further cost reduction. Experimental results show that the 2ECD-MS significantly reduces the total cost against the model using fixed satellites mode by 3.5&#x0025; while the 2ECD-MS-TDD further reduces the total cost against the 2ECD-MS significantly by 3.25&#x0025; in 54 cases with different customer scales, geographical scopes, and distribution types. These show the superiority of the proposed methods in cost reduction for city logistics in comparison to the traditional fixed model.

Star formation in outer rings of S0 galaxies

Aims. Even though S0 galaxies are usually thought to be ‘red and dead’, they often demonstrate star formation organised in ring structures. We try to clarify the nature of this phenomenon and the difference between this occurrence and star formation in spiral galaxies. The luminous S0 galaxy with a large ring, UGC 5936, is studied in this work. Methods. We measured gas and star kinematics by applying long-slit spectroscopy along the major axis of UGC 5936, as well as Lick indices for the main body of the galaxy and strong emission-line flux ratios in the ring. After inspecting the gas excitation in the ring using line ratio diagnostic diagrams and having ensured that it is ionised mostly by young stars, we determined the gas oxygen abundance with popular strong-line methods. We also proved the spatial proximity of the south-eastern dwarf satellite to UGC 5936 and measured its gas metallicity. Results. The ionised gas of the ring is excited by young stars and has solar metallicity. Star formation in the ring is rather prolonged and its intensity corresponds to the current HI content of UGC 5936 (to the Kennicutt-Schmidt relation). The whole morphology of the HI distribution implies current accretion of the cold gas from the satellite onto the outer disc of UGC 5936. The accretion being smooth and laminar provides a favourable condition for star formation ignition; this is a consequence of the satellite location and rotation in the plane of the stellar disc of the host galaxy.

Identifying Predictors of Physical Abuse Evaluation of Injured Infants: Opportunities to Improve Recognition.

To identify predictors of physical abuse evaluation in infants younger than 6 months with visible injury and to determine the prevalence of occult fracture and intracranial hemorrhage in those evaluated. Infants 6.0 months or younger who presented with visible injury to a pediatric hospital-affiliated emergency department or urgent care between July 2013 and January 2017 were included. Potential predictors included sociodemographics, treatment site, provider, injury characteristics, and history. Outcome variables included completion of a radiographic skeletal survey and identification of fracture (suspected or occult) and intracranial hemorrhage. Visible injury was identified in 378 infants, 47% of whom did not receive a skeletal survey. Of those with bruising, burns, or intraoral injuries, skeletal survey was less likely in patients 3 months or older, of black race, presenting to an urgent care or satellite location, evaluated by a non-pediatric emergency medicine-trained physician or nurse practitioner, or with a burn. Of these, 25% had an occult fracture, and 24% had intracranial hemorrhage. Occult fractures were also found in infants with apparently isolated abrasion/laceration (14%), subconjunctival hemorrhage (33%), and scalp hematoma/swelling (13%). About half of preambulatory infants with visible injury were not evaluated for physical abuse. Targeted education is recommended as provider experience and training influenced the likelihood of physical abuse evaluation. Occult fractures and intracranial hemorrhage were often found in infants presenting with seemingly isolated "minor" injuries. Physical abuse should be considered when any injury is identified in an infant younger than 6 months.