Radio Characteristics Research Articles

Bridging simulations of kink instability in relativistic magnetized jets with radio emission and polarisation

Relativistic outflows emanating from active galactic nuclei can extend up to kiloparsec scales in length, displaying a variety of complex morphologies. This study explores the intricate morphologies of such relativistic jets, mainly focusing on creating a bridge between magnetic instabilities in jets with observational signatures from complex radio galaxies. In particular, we aim to study the role of dynamical instabilities in forming distinctive morphological features by employing 3D relativistic magnetohydrodynamic (RMHD) simulations of rotating jets. Our simulations have further used the hybrid Eulerian-Lagrangian framework of the PLUTO code and generated the synthetic synchrotron emission and polarisation maps to compare with the observed signatures. Our analysis based on simulations of a continuously injected jet suggests that current-driven instabilities, notably the |m|=1 mode, generate ribs-like structures that are seen in some of the recent radio galaxies using MeerKat, e.g. MysTail. In our contrasting simulations of the restarted jet, the kink-instability driven ribs-like structures were formed relatively near the nozzle. In both cases, the jet dissipates its pre-existing magnetic energy through these instabilities, transitioning to a more kinetic energy dominant state. The turbulent structures resulting from this dissipation phase are filamentary and resemble the tethers as observed for the case of MysTail. This pilot study essentially provides a plausible qualitative explanation by bridging simulations of kink instability to produce synthetic radio features resembling the observed complex radio morphology of MysTail.

How to Survive Sepsis: Patient Testimonial.

Leaving university I started working for the Belgian National Radio as a journalist. I used to travel a lot and produce radio features about life abroad and how people all over the world dealt with the different challenges in society. A privileged job that I enjoyed doing for many years. In the meantime, I got married and became a mother of two sons. Nothing to worry about, so it seemed, until January 30, 2009. I had been fighting the symptoms of flu for some days. Instead of recovering, I began to feel worse and worse: I had a high fever, was asleep most of the time, could barely eat or drink, and had to cough a lot. The general practitioner sent me to hospital. A few hours later, I had to be reanimated. It was a close call: I was infected by the Streptococcus pyogenes bacteria. My blood started thickening, my organs stopped functioning, and I went into a septic shock, followed by a cardiac arrest. I was successfully reanimated, but still not stable. For 10 days, I was fighting to survive at the intensive care unit (ICU), with several cardiac arrests and reanimations, some of which were long-lasting. The Head of the ICU informed my husband that there was less than 5% chance to survive and if so, he could not predict what kind of damage there would be: the amount of drugs that I had been given, including noradrenaline, was so extremely high, that it became very unclear how my body would respond to it. And if, as by miracle, I would survive: what kind of damage would there be? Physical? Mental? Physical and mental? No specialist could answer those questions. But both the health care professionals and my family fought to keep me alive.

Radio Signature of the Strong Compression between a Streamer and a Coronal Hole Boundary

We present evidence of the first detection of the radio signature at metric wavelengths of the strong compression between a helmet streamer (HS) and the boundary of a coronal hole (CH) using radio observations from the Callisto MEXICO-LANCE and ALASKA-HAARP systems and white-light observations obtained by the STEREO-A/COR1-COR2 coronagraphs. The event occurred very close to the Sun (∼3.4 solar radii) and produced an intense and unusually broad drifting radio feature at metric wavelengths after a downward-drifting band of emission related to a metric Type II radio burst. The compression is caused by the interaction between an expanding structure (coronal mass ejection/shock) and the HS against the CH boundary. Observations in white light show a sharp compressive feature that propagates radially outward, while STEREO-A/EUVI images show loop oscillations at the same position angle, indicating that the interaction occurs across a range of heights. The loop oscillations cease when the compressive front loses its sharp boundary. This transition indicates a reduction of the density compression at the front and the cessation of the radio emission.

Weak-lensing Analysis of the Complex Cluster Merger A746 with Subaru/Hyper Suprime-Cam

The galaxy cluster A746 (z = 0.214), featuring a double radio relic system, two isolated radio relics, a possible radio halo, disturbed V-shaped X-ray emission, and intricate galaxy distributions, is a unique and complex merging system. We present a weak-lensing analysis of A746 based on wide-field imaging data from Subaru/Hyper Suprime-Cam observations. The mass distribution is characterized by a main peak, which coincides with the center of the X-ray emission. At this main peak, we detect two extensions toward the north and west tracing the cluster galaxy and X-ray distributions. Despite the ongoing merger, our estimate of the A746 global mass M 500 = 4.4 ± 1.0 × 1014 M ⊙ is consistent with the previous results from Sunyaev-Zel'dovich and X-ray observations. We conclude that reconciling the distributions of mass, galaxies, and intracluster medium with the double radio relic system and other radio features remains challenging.

A 5G multi-gNodeB simulator for ultra-reliable 0.5–100 GHz communication in indoor Industry 4.0 environments

Industry 4.0 is evolving towards new challenging applications with tight reliability constraints. While simulation tools for the characterization of the physical and radio features of production environments would be very useful, there is a lack of awareness about radio propagation in the presence of 5G technologies. In this context, this paper presents a simulator, based on the 3rd Generation Partnership Project (3GPP) TR 38.901 report, able to describe the physical layer, channel model, and channel modulation applied in 5G. The simulator takes as input the physical characteristics of the considered area and the objects inside of it and provides, with a two-layered approach, the time series of Block Error Rate (BLER) values according to the simulated propagation paths in the presence of moving objects followed by a reliability analysis of the gNodeBs with respect to the user position computed through statistical and geometrical calculations. Through our simulator, we have discovered that the current 5G technology systems may not be sufficient to meet the high reliability demands in safety applications in Industry 4.0 systems. This finding emphasizes the need for additional solutions to enhance the reliability of 5G technology in industrial settings.

The Signature of the Northern Galactic Center Region in Low-velocity UV Absorption

The Galactic Center (GC) is surrounded by plasma lobes that extend up to ∼14 kpc above and below the plane. Until now, UV absorption studies of these lobes have only focused on high-velocity components (∣v LSR∣ > 100 km s−1) because low- and intermediate-velocity (LIV) components (∣v LSR∣ < 100 km s−1) are blended with foreground interstellar medium. To overcome this difficulty, we present a differential experiment to compare the LIV absorption between different structures within the GC region, including the Fermi Bubbles (FBs; seen in gamma rays), the eROSITA Bubbles (eBs; seen in X-rays), and the Loop I North Polar Spur (LNPS) association, an X-ray and radio feature within the northern eB. We use far-UV spectra from Hubble Space Telescope to measure LIV Si iv absorption in 61 active galactic nuclei sight lines, of which 21 pass through the FBs, 53 pass through the eBs, and 18 pass through the LNPS. We also compare our measurements to those in the literature from sight lines covering the disk–halo interface and circumgalactic medium (CGM). We find that the FBs and eBs have enhancements in measured columns of 0.22–0.29 dex in log. We also remove the contribution of a modeled disk and CGM component from the measured Si iv columns and find that the northern eB still retains a Si iv enhancement of 0.62 dex in log. A similar enhancement is not seen in the southern eB. Since a notable difference between the northern and southern eBs is the presence of the LNPS association in the nothern bubble, the northern eB enhancement may be caused by the LNPS.

Exploiting Radio Fingerprints for Simultaneous Localization and Mapping

Simultaneous localization and mapping (SLAM) is paramount for unmanned systems to achieve self-localization and navigation. It is challenging to perform SLAM in large environments, due to sensor limitations, complexity of the environment, and computational resources. We propose a novel approach for localization and mapping of autonomous vehicles using radio fingerprints, for example wireless fidelity or long term evolution radio features, which are widely available in the existing infrastructure. In particular, we present two solutions to exploit the radio fingerprints for SLAM. In the first solution—namely Radio SLAM, the output is a radio fingerprint map generated using SLAM technique. In the second solution—namely Radio+LiDAR SLAM, we use radio fingerprint to assist conventional LiDAR-based SLAM to improve accuracy and speed, while generating the occupancy map. We demonstrate the effectiveness of our system in three different environments, namely outdoor, indoor building, and semi-indoor environment .

Obscuring Environment and X-Ray Variability of Compact Symmetric Objects Unveiled with XMM-Newton and NuSTAR

Compact symmetric objects (CSOs) show radio features such as jets, lobes, and hot spots, which are contained within their host galaxies, and likely represent a recent radio activity. A subpopulation of CSOs with high intrinsic X-ray column densities has been inferred from shallow, soft X-ray band exposures, and observed to cluster in the linear radio size versus 5 GHz radio power plane, which suggests that a dense circumnuclear medium may dramatically influence the growth of compact radio structures. Here, we report on the first detection of two CSOs, 2021+614 and J1511+0518, at energies above 10 keV with NuSTAR. We model the NuSTAR data jointly with the new XMM-Newton data of J1511+0518, and with the archival XMM-Newton data of 2021+614. A toroidal reprocessor model fits the data well and allows us to robustly confirm the X-ray properties of the CSO absorbers and continuum. In both sources, we find intrinsic X-ray absorbing column densities in excess of 1023 cm−2, hard photon indices of the primary emission, Γ ∼ 1.4–1.7, Fe Kα line emission, and variability of the intrinsic X-ray flux density on the timescale of years. The studied X-ray continua are dominated by the primary power-law emission at energies above 3 keV, and by the scattered component at energies below 3 keV. An additional soft X-ray component, modeled with a hot, collisionally ionized plasma with temperature kT ∼ 1 keV, is required by the XMM-Newton data in J1511+0518, which is corroborated by the tentative evidence for the extension in the archival Chandra image of the source.

Efficient Convolutional Networks for Robust Automatic Modulation Classification in OFDM-Based Wireless Systems

Orthogonal frequency-division multiplexing (OFDM) is commonly deployed in Internet of Things (IoT) systems to achieve high data rates with reasonable complexity, where noncooperative protocols encode signals with different modulations for multiple users. However, conventional modulation recognition is limited to single-carrier communication systems, and there is an urgent need to design an effective method to blindly identify the unknown modulation format of received signals. In this article, we propose an automatic modulation classification method for the OFDM systems with the presence of channel deterioration. Our method first leverages a data reconstruction mechanism to arrange signals into high-dimensional data arrays and then exploits an efficient convolutional network, namely OFDMsym-Net, to learn underlying radio characteristics. OFDMsym-Net is designed by two kinds of processing modules, which manipulate one-dimensional asymmetric convolution filters to extract the intracorrelation within an OFDM symbol and the intercorrelation between different symbols. Moreover, a sophisticated structure with addition and concatenation layers is developed inside every module to improve learning efficiency. Based on simulation results achieved on a synthetic dataset of OFDM signals, our proposed method shows the classification robustness under various channel impairments. It reveals to have an overall accuracy of 95.41% at 10-dB signal-to-noise ratio, being superior to several state-of-the-art approaches.

A Survey on DRX Mechanism: Device Power Saving From LTE and 5G New Radio to 6G Communication Systems

The Discontinuous Reception (DRX) is the most effective timer-based mechanism for User Equipment (UE) power saving. In Long Term Evolution (LTE) systems, the development of the DRX mechanism enormously extends the UE battery life. With the DRX mechanism, a UE is allowed to enter a dormant state. Given a DRX cycle, the UE needs to wake up periodically during the dormancy to check whether it receives new downlink packets or not. The UE can achieve a high sleeping ratio by skipping most channel monitoring occasions. As the mobile network evolved to 5G, the battery life requirement increased to support various new services. 3rd Generation Partnership Project (3GPP) also enhances the DRX mechanism and adds new DRX-related features in the New Radio (NR) Release 16 standard. In addition to the time-based design, 3GPP proposed two signaling-based mechanisms: power saving signal and UE assistance information. This survey paper introduces the latest DRX mechanism in the 3GPP NR standard and summarizes the state-of-the-art research. Researchers have investigated the DRX mechanism in various use cases, such as Web browsing services and heterogeneous networks. They focus on the UE sleep ratio and packet delay and propose corresponding analytical models. New DRX architectures are also discussed to conquer the power-saving problem in specific schemes, especially in the 5G NR networks. This paper categorizes and presents the papers according to the target services and the network scenarios in detail. We also survey the work focusing on the new challenges (such as beamforming and thermal issue) in the NR network and introduce the future research directions in the 6G era.

RadioSES: mmWave-Based Audioradio Speech Enhancement and Separation System

Speech enhancement and separation have been a long-standing problem, especially with the recent advances using a single microphone. Although microphones perform well in constrained settings, their performance for speech separation decreases in noisy conditions. In this work, we propose <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RadioSES</small> , an audioradio speech enhancement and separation system that overcomes inherent problems in audio-only systems. By fusing a complementary radio modality, <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RadioSES</small> can estimate the number of speakers, solve the source association problem, separate and enhance noisy mixture speeches, and improve both intelligibility and perceptual quality. We perform millimeter-wave sensing to detect and localize speakers and introduce an audioradio deep learning framework to fuse the separate radio features with the mixed audio features. Extensive experiments using commercial off-the-shelf devices show that <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RadioSES</small> outperforms a variety of state-of-the-art baselines, with consistent performance gains in different environmental settings. Similar to the audiovisual methods, <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RadioSES</small> provides significant performance improvements 3 dB gains in SiSDR, when compared with the corresponding audio-only method, along with the benefits of lower computational complexity and better privacy preservation.

The NuSTAR and Chandra View of CL 0217+70 and Its Tell-tale Radio Halo

Mergers of galaxy clusters are the most energetic events in the universe, driving shock and cold fronts, generating turbulence, and accelerating particles that create radio halos and relics. The galaxy cluster CL 0217+70 is a remarkable late-stage merger, with a double peripheral radio relic and a giant radio halo. Chandra detects surface brightness (SB) edges that correspond to radio features within the halo. In this work, we present a study of this cluster with Nuclear Spectroscopic Telescope Array and Chandra data using spectro-imaging methods. The global temperature is found to be kT = 9.1 keV. We set an upper limit for the inverse Compton (IC) flux of ∼2.7 × 10−12 erg s−1 cm−2, and a lower limit to the magnetic field of 0.08 μG. Our local IC search revealed a possibility that IC emission may have a significant contribution at the outskirts of the radio halo emission and on/near shock regions within ∼0.6 r 500 of clusters. We detected a “hot spot” feature in our temperature map coincident with an SB edge, but our investigation on its origin is inconclusive. If the “hot spot” is the downstream of a shock, we set a lower limit of kT > 21 keV to the plasma that corresponds to ∼2. We found three shock fronts within 0.5 r 500. Multiple weak shocks within the cluster center hint at an ongoing merger activity and continued feeding of the giant radio halo. CL 0217+70 is the only example hosting these secondary shocks in multiple form.

5G New Radio for Public Safety Mission Critical Communications

Driven by increasing demands on connectivity to improve safety, situational awareness and operational effectiveness for first responders, more and more public safety agencies are realizing the need of modernization of their existing non-3GPP networks. 3GPP based cellular networks offer the unique opportunity of providing fast, reliable, and prioritized communications for first responders in a shared network. In this article, we give an overview of service requirements of public safety mission critical communications. We identify key technical challenges and explain how 5G new radio (NR) features are being evolved to meet the emerging safety critical requirements, including enabling connectivity everywhere, supporting efficient group communications, prioritizing mission critical traffic, and providing accurate positioning for first responders.

A Study of Radio Knots within Supernova Remnant Cassiopeia A

The study on the dynamic evolution of young supernova remnants (SNRs) is an important way to understand the density structure of the progenitor’s circumstellar medium. We have reported the acceleration or deceleration, proper motion, and brightness changes of 260 compact radio features in the second-youngest known SNR Cas A at 5 GHz based on the Very Large Array data of five epochs from 1987 to 2004. The radio expansion center is located at α(1950) = 23h21m9.ˢ7 ± 0.ˢ29, δ(1950) = +58°32′25.″2 ± 2.″2. Three-quarters of the compact knots are decelerating; this suggests that there are significant density fluctuations in the stellar winds of the remnant’s progenitor. We have verified that the acceleration or deceleration of compact knots is not related with the distribution of brightness. The brightening, fading, disappearing, or new appearing of compact radio features in Cas A suggests that the magnetic field in the remnant is changing rapidly.

THE DIRECTOR'S STRATEGY IN BUILDING A THEATER OF MIND ON THE P.O.V. EPISODES OF RADIO FEATURE PROGRAM MINIMAL-IS-ME

Background: The production of this radio feature work focuses on providing options for young people to overcome financial problems that have an impact on psychology by applying a lifestyle of minimalism, in addition to the history of minimalism and the direct story of people who apply minimalism in everyday life. minimalism lifestyle is one way to overcome the overconsumption lifestyle that exists in society.&#x0D; &#x0D; Objective: The purpose of creating this production work was to produce a radio feature work with the title "P.O.V." episode of "Minimal-is-me" through the application of Theater of Mind as a director's strategy by maximizing the three elements of radio, namely voice, music and sound effect.&#x0D; &#x0D; Methods: Creation of production works using the methods of stages of creation, pre-production, production, and post-production.&#x0D; &#x0D; Results: The application of fragments in this production can maximize the three elements of radio namely voice, music and sound effects to bring the listener's Theater of Mind to life. so that the listener can feel the characteristics of the radio and can receive the message conveyed well.&#x0D; &#x0D; Conslusion: Feature radio is an excellent program to provide information to listeners because it can be packed with several sub-formats so that the work can be more interesting to listen to. In the Feature program, there are some surprises for the listener because the listener can't guess what will happen next. Featured radio "P.O.V". The episode "Minimal-is-me" discusses the lifestyle of minimalism in society through real cases contained in fragments as well as problem solving through various aspects such as psychology, economics, and how minimalism is beneficial to a person's life

Transition in Optical and Radio Features During the Early Development of Negative Intracloud Leader

AbstractWhat happens when the upward in‐cloud (IC) breakdown transitions into horizontally expanding extension? Optical observations of this transition in IC lightning have not previously been reported. We identify the radio and optical signatures of this transition in low‐frequency (LF) magnetic, very high frequency interferometric and space‐borne optical measurements. For initial IC development in stratiform clouds, the ratio of 337/777.4 nm radiance is above unity prior to the transition but is almost always below unity after the transition. In particular, the 337 nm radiance drops significantly while the 777.4 nm radiance remains almost invariant after the transition, suggesting when the dominant illumination process of IC leaders changes from cold streamer discharges to a likely stepped leader. Furthermore, this transition in the LF and optical measurements resembles the reported changes in the cloud‐to‐ground measurements from initial leader to stepped leader, indicating that the initial leader may be physically different from the stepped leader.

Implementasi Critical Path Method dalam Produksi Feature Radio “Sudut Pandang” Episode “Mengenal Stunting”

The production of radio feature “Sudut Pandang” Episode of “Mengenal Stunting” imlements the Critical Path Method to map out all the steps need to be taken in order to complete and identify activities based on the priority; and also to identify the sequence of activities to complete first or need to be completed at the same time. It begins by determining the amount of time required to critically complete the priority work path, and analyzing the relationship between program requirements and available human resources, as well as the time required to complete production.The result of the Critical Path Method implementation is network analysis schedule that has succeeded in optimizing the total cost of production by reducing or accelerating the completion time of production activities in the creation of radio feature production works.

Transition in Optical and Radio Features during the Early Development of Negative Intracloud Leader

Transition in Optical and Radio Features during the Early Development of Negative Intracloud Leader

X-Ray Jets in the High-redshift Quasars J1405+0415 and J1610+1811

We investigate Chandra X-ray observations of the radio-loud quasars J1405+0415 and J1610+1811 at redshifts z = 3.215 and z = 3.122, respectively, for evidence of extended X-ray emission. Observations totalling 95 ks per target are combined, and X-ray jets that are spatially coincident with known radio features are detected at a greater than 4σ significance. Hardness ratios and emission spectra are determined for all X-ray features, and X-ray fluxes and luminosities are measured. Jet-to-core X-ray flux ratios are estimated for each system, and the ratios are consistent with those observed for nearby and more distant jet systems, although the spread in the parameter is large. These results suggest that to first order the X-ray jet emission mechanisms are redshift invariant. In addition to the extended emission analysis, incorporating also archival data from Swift, we examined the properties of a decline in the Chandra flux from the active galactic nucleus (AGN) of J1610+1811 observed between 2018 and 2021. We conclude that the variability is most likely due to a flaring event that occurred between the years 2017 and 2018 and originated from either the AGN or the inner jet region.

Radio: The Indigenous Peoples Media Construction of the Concept of Na-tion

This study explored whether radio had an impact on the indigenous peoples or Bihug of Camarines Norte, Philippines in developing their concept of nation. Descriptive and exploratory research designs were used. Through a multi-level approach, the intensive qualitative component of the research procedure was addressed, the construction of the indigenous peoples’ concept of nation through radio listening. Thematic analysis was used to process the data gathered. The study employed Anderson’s theory on imagined communities as a social construction and Crisell’s characteristics of radio. Radio in the community of the indigenous peoples did not appear to play a primary role in the construction of their concept of nation; rather their actual encounters with people in various activities, their knowledge of places, the recognition given to their benefactors and stories from ancestors which helped in the realization of the extent of their assimilation with the lowlanders, their being Filipino, and their membership of a minority group were the main contributory factors. Although radio was not the main source, it contributed to the formation of their concept of nation as events, places, sense of belongingness, and benefactors. This study, which dealt with the role of radio in the formation of the indigenous peoples’ concept of nation in Camarines Norte, Philippines also considered other factors which may influence the construction of a concept of nation aside from radio like other mass media, and their social encounters with members of NGOs, other agencies and institutions, barangay officials and the constituents of the community where they stay.