esa-sceva/satcom-chunk-collection huggingface dataset:
# Denoising Directional Room Impulse Responses with Spatially Anisotropic Late Reverberation Tails
###### Abstract  
Directional room impulse responses (DRIR) measured with spherical microphone arrays (SMA) enable the reproduction of room reverberation effects on three-dimensional surround-sound systems (e.g., Higher-Order Ambisonics) through multichannel convolution. However, such measurements inevitably contain a nondecaying noise floor that may produce an audible \"infinite reverberation effect\" upon convolution. If the late reverberation tail can be considered a diffuse field before reaching the noise floor, the latter may be removed and replaced with an extension of the exponentially-decaying tail synthesized as a zero-mean Gaussian noise. This has previously been shown to preserve the diffuse-field properties of the late reverberation tail when performed in the spherical harmonic domain (SHD). In this paper, we show that in the case of highly anisotropic yet incoherent late fields, the spatial symmetry of the spherical harmonics is not conducive to preserving the energy distribution of the reverberation tail. To remedy this, we propose denoising in an optimized spatial domain obtained by plane-wave decomposition (PWD), and demonstrate that this method equally preserves the incoherence of the late reverberation field.  
DRIR; SMA; reverberation; HOA; denoising; SHD; PWD
## 9 Conclusions  
This paper discusses UWSNs, underwater localization, localization techniques, and current challenges in the underwater environment. The main subject of the paper was the recent methods for underwater localization. The crucial topic of localization for the UWSN is one of considerable interest for scientists researching underwater localization. This paper provides detailed explanations of the specific underwater localization characteristics. The paper also looked at the localization's foundational ideas, structure, and methods for underwater localization. The effectiveness of several underwater localization techniques is explored and contrasted. A range-based localization technique that uses TDoA, ToA, AoA, and RSSI is also covered. This paper's conclusion discussed the difficulties and problems surrounding underwater audio communication and localization. Because each localization approach has unique benefits, drawbacks, and consistencies for a particular context, it is hard to declare that one is better than all others. This review's primary objective is to advance young researchers in the field by setting the framework for the previously proposed underwater localization. Even if the arena of USNs, in addition to localization, is expanding rapidly, numerous issues still call for additional study.  
K.S.; Conceptualization, Data curation, Formal Analysis, Methodology, Software, Writing--original draft; R.C.V.; Supervision, Writing--review & editing, Project administration, Visualization; R.A.; Visualization, Investigation, Formal Analysis, Software; G.P.; Data curation, Investigation, Resources, Software, Writing--original draft, Methodology. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research received no external funding.  
\begin{table}
\begin{tabular}{p{56.9 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Literature Study** & **Year** & **Main Role** & **Scope** & **Limitation** \\ \hline \multirow{4}{*}{**[PERSON] et al. [75]**} & \multirow{4}{*}{2019} & As a result, channel utilization could be improved. ALOHA-Q was upgraded in the new model (UW-ALOHA-Q) & Improvements to UW-ALOHA-Q & Due to heavy weight and environment \\  & & & They also examined a few additional categories, including MAC, routing protocols, natural elements, restriction, and channel association & Rising channel usage, media, and directing receive structured control protocols & The underwater acoustic channel places significant restrictions on localization systems due to its unique characteristics of high bandwidth, substantial delay, and high error rates \\ \hline \multirow{4}{*}{**[PERSON]
# Development of a Power and Communication Bus Using HIL and Computational Intelligence
## 3 Motivation  
Regarding multiple of the same devices on the line, for example, 25 lighting/sensor/ actuator modules which are in one element in the car, for example, door side/cockpit/ middle console, the possibility of auto-addressing can radically reduce cost, materials and time for production. Nowadays, a 4-line solution is commonly used in the case of auto-addressing, one pair of power supplies, and one pair of LIN_in, and LIN_out signals [16]. In this paper, the authors propose a solution for how to use only two wires, for power, transmitting data and auto-addressing. While auto-addressing is the ability to give a unique ID to each slave node on the line, ID defines the position on the line. Data transmission was designed and tuned using engineering methods with promising results, nevertheless tuning the auto-addressing features required to use artificial intelligence algorithms such as genetic algorithms [22] and particle swarm optimization, due to the number of possible combinations.  
\[\beta=\sum_{i=0}^{7}\Big{(}\max(p_{h_{i}})-\min(p_{h_{i}}))+(\max(p_{s_{i}})- \min(p_{s_{i}})\Big{)}=5.58\times 10^{13}. \tag{1}\]  
Due to the goal of finding a global optimum and a nonlinear function with discrete values, gradient methods cannot be used, mainly due to the stochastic nature of the objectives and because there are continuous and discrete decision variables in the vector \(\mathbf{p}\) (more details can be seen in Section 3). The authors decided to use an experiment planning method, genetic algorithm and particle swarm optimization to compare results and check if given results can be treated as a global optimum.  
The idea for solving the auto-addressing task was to inject by master a disruption which will be reflected and modified by the client, and at the end the master signal will be sampled. Such a solution is very difficult to test in a virtual environment. The authors decided to connect the whole system to hardware-in-the-loop instead of trying to build a mathematical model according to the Jaguar Land Rover approach, which connects the windscreen wiper for the hardware-in-the-loop setup [23] and other non-automotive researchers who optimized the buck converter [22], and validated PID using HIL [24].
## 6 Overview of Existing AI Techniques for NTN-Based IIoT
### Practical Limitations and Open Issues
Based on the review of the research results in this section, one can conclude that the forceful DL represents the most popular and widely used AI-based technique, enabling not only data classification but also feature extraction as soon as a large amount of training measured data is available and the computation capabilities are sufficient. Nevertheless, the limited processing capabilities and power resources of spaceborne and airborne platforms may discourage the application of DL. One may ideally move more computing power to space and air in the future, but current practical constraints enjoin the design and implementation of low-power and efficient DL solutions. To overcome the limitations of resources, cloud-centric DL schemes can be used that require data transmission from the satellites and the aerial platforms to a centralized server. To avoid network overhead during transmissions to centralized entities and collaboratively and locally train DL-based learning models on IoT devices, employing federated DL (FDL) is proposed [128]. Besides the above, computationally simpler AI methods, e.g., RL, which can be implemented in a distributed manner and in resource-constrained devices, seem promising. As many critical applications require rapid learning procedures to obtain URLLC, introducing specific constraints into the optimization procedure and/or confidence scores to predictions can dramatically decrease the computation time. To further improve the performance of SAGINs and satisfy the requirements of quality of experience (QoE), jointly optimizing the communication, caching, energy, and computing resources is also suggested. Finally, experimental testing of the proposed learning frameworks through measurements in realistic testbed environments is required in order to validate the hitherto theoretical results. In this regard, non-identical spaceborne and airborne types with variant orbits, velocities, altitudes, and antenna designs can be employed while conducting similar experiments.
## 6 Conclusions
In Proceedings of the 2003 IEEE Wireless Communications and Networking, New Orleans, LA, USA, 16-20 March 2003; Volume 2, pp. 1124-1130. [CrossRef]
* [PERSON] (2016) [PERSON] Distributed Databases Synchronization in Named Data Delay Tolerant Networks. Master's Thesis, Department of Informatics, University of MINHO, Braga, Portugal, October 2016. * [PERSON] and [PERSON] (2007) [PERSON]; [PERSON] [PERSON] Distance aware collision avoidance protocol for ad-hoc underwater acoustic sensor networks. _IEEE Commun. Lett._**2007**, _11_, 1025-1027. [CrossRef]
* [PERSON] et al. (2008) [PERSON]; [PERSON]; [PERSON] [PERSON] A comparative performance evaluation of MAC protocols for underwater sensor networks. In Proceedings of the OCEANS 2008, Quebec City, QC, Canada, 15-18 September 2008; pp. 1-10. [CrossRef]
* [PERSON] and [PERSON] (2008) [PERSON]; [PERSON]; [PERSON] [PERSON] T-Lohi: A New Class of MAC Protocols for Underwater Acoustic Sensor Networks. In Proceedings of the IEEE INFOCOM 2008--The 27 th Conference on Computer Communications, Phoenix, AZ, USA, 13-18 April 2008; pp. 231-235. [CrossRef]
* [PERSON] and [PERSON] (2008) [PERSON]; [PERSON]; [PERSON] Comparison and Evaluation of the T-Lohi MAC for Underwater Acoustic Sensor Networks. _IEEE J. Sel. Areas Commun._**2008**, _26_, 1731-1743. [CrossRef]* _[PERSON]_ _et al._ (2019) [PERSON]; [PERSON] Avoiding and Isolating Flooding Attack by Enhancing AODV MANET Protocol (AIF_AODV). _Secur. Commun. Netw._**2019**, _2019_, 8249108. [CrossRef]
* [PERSON] (2007) [PERSON] Information-Carrying Based Routing Protocol for Underwater Acoustic Sensor Network. In Proceedings of the 2007 International Conference on Mechatronics and Automation, Harbin, China, 5-8 August 2007; pp. 729-734. [CrossRef]
* _[PERSON]_ _et al._ (2012) [PERSON]; [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON]; [PERSON] [PERSON] DESERT Underwater: An NSMiraclebased framework to DESign, Simulate, Emulate and Realize Testbeds for Underwater network protocols. In Proceedings of the IEEE/OES Oceans, Yeosu, Republic of Korea, 21-24 May 2012. [CrossRef]
* _[PERSON]_ _et al._ (2015) [PERSON]; [PERSON]; [PERSON] EviNS: Framework for development of underwater acoustic sensor networks and positioning systems. In Proceedings of the OCEANS 2015, Genova, Italy, 18-21 May 2015. [CrossRef]
* _[PERSON]_ _et al._ (2018) [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] An Underwater Digital Network on Acoustic Modems with EviNS Framework: A Case Study. _Gyroscopy Navig._**2018**, \(9\), 325-333. [CrossRef]

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## 3 Results
### Impact of CNCORS on BDS Single-System POD
#### 3.2.3. SLR Assessment  
The SLR test results of strategies 3 and 4 are shown in Table 10. The table shows that the BeiDou single-system and BDS/GPS joint orbit determinations present consistent features: the CNCORS have the greatest impact on IGSO satellites, followed by MEO satellites, and the least impact on GEO satellites.
# A Staring Tracking Measurement Method of Resident Space Objects Based on the Star Tacker
## 1 Introduction
The satellite stares at the same target by adjusting the attitude when performing staring imaging, which increases the observation time compared with traditional push-broom imaging [29]. Obviously, this staring imaging model can significantly extend the measurement arc length of RSOs in one observation, which is very suitable for solving the TSA problem in accurate RSO position determination. Therefore, a staring-tracking measurement (STM) method is proposed in this paper to obtain a sufficiently long arc RSO observation by star trackers. The proposed STM method completes both the tracking and the observation of the RSO. Firstly, the expected attitude of the satellite is calculated for staring at the RSO and collecting long-arc measurement data. Additionally, a position vector measurement method based on the principle of angular distance invariance and the imaging mapping function of the star tracker is then proposed in the process of staring-tracking for RSOs. This paper is organized as follows: the attitude planning model of the satellite for staring-tracking, and the measurement method of the RSO position vector are introduced in Section 2. The simulations and experiments of the proposed method were carried out in Section 3. The discussions based on the results in Section 3 are given in Section 4, and the conclusions are given in Section 5.
# A Miniaturized and Fast System for Thin Film Thickness Measurement
## 5 Experiments and Discussion  
To verify the correctness and effectiveness of the proposed algorithm, this paper built a miniaturized thin film thickness measurement system as shown in Figure 9. The experimental system consists of a three-axis translation stage, a commercial fiber spectrometer, and a self-developed small achromatic microscope probe. The probe is mounted on the Z-axis guide rail and the Z-axis guide rail is fixed on the XY table. The \(X\), \(Y\), and \(Z\)-axis guide rails drive the translation and lifting of the probe, to realize the rapid and high-precision scanning measurement of the film sample.  
To ensure the measurement accuracy of the system, the experiment performs wavelength calibration on the spectrometer and eliminate high-order diffraction by measuring the spectral line of a mercury-argon standard light source in the range of 300-1000 nm. The standard wavelength values of the characteristic spectral line of the light source are provided by the National Institute of Standards and Technology (NIST) [23]. The corresponding relationship between the wavelength and the index of each CCD pixel is obtained by the second-order fitting.  
Figure 8: The influence of local Gaussian noise on the calculated thickness deviation. (**a**) Reflection spectrum signal including local Gaussian noise of 9 \(\upmu\)m thickness film. (**b**) Power spectral density and power spectrum calculated using Lomb-Scargle periodogram (LSP) and cubic spline interpolation combined fast Fourier transform (CIFFT) respectively membrane thickness.  
Figure 9: Experimental measurement system setup.
# Oceania's 5G Multi-Tier Fixed Wireless Access Link's Long-Term Resilience and Feasibility Analysis
## 3 5G Base Coverage Network Layout
### Enhancing 5G Wireless Communication's SNR and Channel Capacity Using Antenna Arrays  
A wireless communication system's objective is to provide the most users with the highest data rate feasible while adhering to limitations like the radiation power limit and operating budget. Signal-to-noise ratio (SNR) improvement is crucial for increasing data rates. Reusing resources is essential for providing services to more people. Numerous techniques have been used over the past few decades to increase SNR and reuse time, frequency, and coding space resources [57]. This illustration demonstrates how using antenna arrays can increase a wireless link's SNR and capacity.  
Currently, antenna arrays are part of the standard configuration for 5G wireless communication networks. The notion of massive MIMO, which, as the name suggests, involves the deployment of MIMO technology on a much larger scale for higher network coverage and capacity, is introduced by 5G New Radio, taking it to the next level. To boost transmission gain and spectral efficiency, massive MIMO employs numerous additional broadcast and receive antennas. There must be simultaneous downlink traffic generation from several UEs to achieve massive MIMO capacity gain. The actual gain that massive MIMO provides is affected by several factors [58]. Massive MIMO applications do not have a set minimum number of antennas needed; however, most experts agree that a system needs more than eight broadcast and eight receive antennas. Additional systems with tens  
Figure 11: 5G network coverage and SINR map for 16-by-16 antenna array assigned for each cell transmitter and applied down-tilt at Samabula Campus of Fiji National University, Fiji.  
or even hundreds of antennas are possible; thus, the number can be significantly higher. It is possible for the system to reuse its geographic data to provide more coverage. For the sake of this example, let us assume that the system is placed at 30 GHz, a band that is currently being considered for the 5G network.
###### Abstract  
This work presents a novel approach to detecting stress differences between experts and novices in Situation Awareness (SA) tasks during maritime navigation using one type of wearable sensor, Empatica E4 Wristband. We propose that for a given workload state, the values of biosignal data collected from wearable sensor vary in experts and novices. We describe methods to conduct a designed SA task experiment, and collected the biosignal data on subjects sailing on a 240\({}^{\circ}\) view simulator. The biosignal data were analysed by using a machine learning algorithm, a Convolutional Neural Network. The proposed algorithm showed that the biosignal data associated with the experts can be categorized as different from that of the novices, which is in line with the results of NASA Task Load Index (NASA-TLX) rating scores. This study can contribute to the development of a self-training system in maritime navigation in further studies.  
biosignal; maritime navigation; classification; situation awareness (SA); neural network; maritime training +
Footnote †: journal: Medical  
attributed to SA-related problems. Therefore, training maritime students to improve their SA is one of the most important tasks in maritime education.  
In maritime navigation, an experienced navigator can keep track of multiple tasks and deal with more complex situations without losing SA as compared to a novice. For a novice, managing multiple tasks required for navigation can be quite challenging [4]. As navigating a ship can be stressful, managing this stress can bring different results. In this study, we aim to investigate whether there are differences in the biosignals between the experts and novices for a given sailing task.
## 3 Test Details
### Enabling Load TH Test Legs
#### 3.1.5 Failure Analysis and Root Cause Failure  
X-sections showed that all contacts remained on pads (even for the open failure chain), as shown in Figure 11. Scanning electron microscope (SEM) showed that, for the pad from failing chains, there was the presence of nickel oxides. For functional chains, there were mostly no signs of other elements besides Au, as shown in Figure 12. Even during the appearance of other elements for good chains, the contact forces were believed to be strong enough to penetrate through the foreign materials in order to make good contact with the pads.  
Figure 11: X-section of a failed chain.  
Figure 12: Scanning electron microscope (SEM)of pad from failing chain and good chain.  
Figure 10: Contact force distribution under step load only.  
TH FM: The metallurgical surface finish for the package and the contacts was typically electrolens nickel and immersion gold plating (ENIG). A typical industry process for ENIG [2] is such that the immersion gold (IG) is deposited on top of electroless Ni (EN), which is on top of the Cu layer. EN serves as a diffusion barrier for copper metallization, whereas IG acts as a protective overcoat to protect Ni from oxidation. Since a gold atom is much larger than a nickel atom, the room between nickel atoms may not be fully filled in by gold atoms, thus small voids are formed during the displacement reaction. The presence of gold pores exposed the nickel underneath, and under high relative humidity environment, diffusion brings nickel ions to the surface, resulting in the formation of nickel oxidation, as shown in Figure 13. At time zero, it was expected that even though the entire contact surface was not all gas tight, the contacting spots could be considered gas tight [3]. Therefore, good LLCR was always established at T0. With time passing, corrosion was accelerated under high relative humidity and stress relaxation occurred. The mating locations could change due to stress relaxation, and this was how corrosion products got between the original contacting spots. In hot humid environments, the high temperature also adversely impacted electrical performance. It not only sped up corrosion, but also caused more severe stress relaxation. In extreme severity, oxidation in TH could lead to electrical failures, such as high resistances or electrical opens.  
Note that, besides the nickel oxidation type of corrosion, there were some other commonly seen TH FMs, such as fretting, that caused the wear of the coating material on the contact surface, then exposed the EN layer, or even exposed the base material of the Cu layer, resulting in the decrease of the electrical contact performance, such as wiping, dust, industrial corrosive gases, etc.