esa-sceva/satcom-chunk-collection huggingface dataset:
# Communication Architecture in Mixed-Reality Simulations of Unmanned Systems
## 4 Requirements for Communication Architecture  
A communication subsystem in MR simulations needs to provide the following features to enable interaction between all the entities in an MR simulation and sustain the high fidelity of testing and verification.  
* **Addressing--**Both SWEs and HWEs need to use unique addresses in a common address space to distinguish message receivers. In addition, messages need to have the option of being addressed selectively (not broadcast) so that (i) information is not given to entities that should not have it (e.g., when not covered by their sensors), (ii) the processing power of entities that are not receivers of the message is spared, and (iii), in some cases, wireless medium bandwidth is saved (e.g., when multiple wireless channels are used for communication or a directional information transfer methods are employed).
* **Transparent routing--**The system must provide the transparent routing of messages between SWEs and HWEs.
* **Identical message management--**Messages of HWEs and SWEs need to be managed similarly. Using different mechanisms for processing of HW and SW messages can bias tests regarding measurements of communication throughput, topology management, and team coordination.
* **Visibility model--**The system must be able to model communication visibility among all entities in the simulation (either based on their physical reachability or based on a signal propagation model) to provide high-fidelity simulations.
* **Network partitions--**In the case of two or more vehicles being out of communication range of the others and/or the simulation platform (i.e., GCS), the system should ensure that communication inside these newly created network partitions remain untouched.
* **Sharing single address--**When a communication bridge/relay between the networks of HWEs and SWEs is used, such entities need to be able to handle addressing using a single address of the bridge. It is necessary to determine the physical destination address of the messages that need to be relayed to other network types.  
These features are important for the correct function of the MR simulation framework, high fidelity validation, and testing, and it is mandatory to compose them within a single architecture of an MR communication system, which is proposed in the following section.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Type** & **Tools** & **Visibility** & **Method** \\ \hline HWE-HWE & modems & physical & direct (modems) \\ SWE-SWE & sockets & SW model & direct (sockets) \\ HWE-SWE & combined & SW models (limited by physical vis) & message relay \\ \hline \hline \end{tabular}
\end{table}
Table 1: Types of communication connection in MR simulation systems.
## 3 Possible Transport Evidence for Intermediate Phases and Wigner Crystal Melting  
Since the discovery of the RIPs at a lower magnetic field \(v>1\) implies a liquid to Wigner crystal transition in clean 2D systems with high \(r_{\rm s}\), then an important question arises: What type of phase transitions are experimentally observed for a 2D metallic liquid to insulator transition (whereas the insulator is either the zero-field insulator or the RIPs at a low magnetic fields). Given the well-known theoretical results that there is no long-range order in a 2D solid and the possible existence of various phases intermediate between a 2D WC and a liquid [20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33], is there any experimental evidence for intermediate phases when a WC melts into liquid?  
Evidence of intermediate phases has been presented by several groups [34; 35; 36]. [PERSON] et al. studied how the low field RIP is suppressed by either increasing the temperature or carrier density and found evidence for the 2D holes in p-GaAs transforming into a mixed state of an incipient RIP and a metallic liquid [34]. Other researchers took a different approach and used an increasing voltage (or electric field) applied to the sample to probe the breakdown of a presumed 2D WC deep in the insulating state where the resistivity is very high. In such a state where the WC is presumably well  
Figure 6: (**a**) Magnetoresistance of 2D holes in GaAs showing two RIPs at \(\
u>1\) (labeled as P1 and P2). (**b**) mechanism (thermal activation vs. variable-range-hopping) (**d**) The longitudinal resistivity \(\rho_{\rm xx}\) and inductive signal Y\({}_{\rm xx}\) vs. frequency at various magnetic fields, showing the clear inductive effect of the RIPs. Figure taken from Reference [12].  
formed, [PERSON] [35] and [PERSON] [36] found non-linear I-V curves at low temperatures, shown in Figures 7 and 8. Different threshold voltages were seen, suggesting a two-stage phase transition instead of a direct phase transition, although different explanations were given by the two groups. More experimental data and theoretical models are needed to further elucidate the situation.
# Inverse Solution Error Analysis and Correction of Beam Steering System Based on Risley Prisms
## 2 Error Model of Risley Prisms and Forward Solution Error Correction Method
### Error Model of Risley Prisms
Substituting the above vectors into Formula (1) in turn for calculation, the emitted light vector \(\overset{\rightarrow}{A}_{5}=(K^{\prime},L^{\prime},M^{\prime})\) can be derived. Figure 4: Diagram illustrating the assembly errors of the prisms and their notation.
# Heuristic Routing Algorithms for Time-Sensitive Networks in Smart Factories
## 4 Improved Genetic Algorithm to Solve TT Flow Routing Problem
### Description of GATTRP
#### 4.3.3 Genetic Evolution Operator Design  
We combined simple operators, such as the _flip, slide, swap_ mutation, to design relatively complex operators, which improved the diversity of the mutation process, accelerated the evolution process, and, eventually, enhanced the efficiency of the GA.  
In existing mutation operators, the route length of each traveling salesman is constant, which is not enough to effectively improve the population diversity and it is detrimental to locally search for new possible solutions. Therefore, for the second segment of the chromosome, the operation of \(+n\), \(-n\) or \(+0\) was randomly applied to the breakpoint gene segments on the premise that the breakpoints were not equal to each other and were arranged in ascending order. The effect of the above operations was a change in the length of the salesmen's routes. The mutation process is depicted in Figure 6.
# Implementing Many-Lights Rendering with IES-Based Lights
## 2 State of the Art on Many-Lights Rendering Techniques
### Reflective Shadow Maps  
We provide here a description of the _Reflective Shadow Maps_[8] method, which we have extended in this paper.  
The technique is based on the consideration that all one-bounce indirect illumination for a light source is related to the surfaces \"visible\" via the light source during the generation of a standard shadow map. Thus, each pixel of a light source's shadow map can be considered a virtual light source for the rest of the scene, and it can simulate the bounce of light on that surface. On such a premise, virtual lights generation corresponds to rasterization from the point of view of the light source.  
A Reflective Shadow Map (RSM), as described in [8], stores for each pixel \(p\):  
* a depth value, \(d_{p}\), as in a standard shadow map;
* the world space position of the pixel \(\mathbf{x}_{p}\);
* the normal in world space \(\mathbf{n}_{p}\);
* the reflected radiant flux \(\Phi_{p}\), which corresponds to the amount of luminous power leaving a surface.  
The technique follows a standard deferred rendering approach, saving each of these data in different dedicated G-buffers in a first render step and finalizing the rendering process in a final second step.  
The following equation  
\[E_{p}(\mathbf{x},\mathbf{n})=\Phi_{p}\frac{\max(0,\mathbf{n}_{p}\cdot(\mathbf{ x}-\mathbf{x}_{p}))\max(0,\mathbf{n}\cdot(\mathbf{x}_{p}-\mathbf{x}))}{|| \mathbf{x}-\mathbf{x}_{p}||^{4}} \tag{3}\]  
describes how the virtual light source identified by the pixel \(p\) in the RSM illuminates the surface point \(\mathbf{x}\) having a normal \(\mathbf{n}\). Adding up the contributions of each pixel/virtual light allows the computation of the indirect lighting received by the point. However, the generated RSM is moderately large (\(512\times 512\) pixels/virtual lights), and its use would not be compatible with a real-time rendering context. To reduce the number of sums, an importance sampling_ approach is applied in order to concentrate the sampling of the RSM to a subset of relevant lights. The approach is based on the consideration that, the closer a virtual light source \(p\) is to the point \(\mathbf{x}\), the more it will contribute to its illumination. The distances between two points in image space can be considered a reasonable approximation for distances in world space; thus, the point \(\mathbf{x}\) is projected to the image space, and then the texture is sampled using Poisson disk sampling.  
The technique as presented in [8] considers only diffuse surfaces, and it is applied to directional lights and spotlights only, which can be treated using standard 2D texture images, due to the strong directionality of these kinds of light sources. The authors suggested that the technique could be extended to consider _omnidirectional_ lights like point lights. In our proposed approach, we present an extension of the RSM technique characterized by the use of cube maps to manage the multiple emission directions of a VPL.
# Privacy-Preserving Authentication Based on PUF for VANETs
## 3 Preliminaries
### Vehicle Registration  
CA generates an identity \(ID_{v}\), selects a random number \(r_{v}\in Z_{q}^{*}\) for a vehicle, and generates the pseudonym \(AID_{v}\) for the vehicle, where \(AID_{v}=H(sk_{c}||r_{v})\oplus ID_{v}\). Then, select a random number \(y_{v}\in Z_{q}^{*}\), calculate \(S_{v}=y_{v}P\) and \(T_{v}=y_{v}S_{v}\), CA sends \(\{AID_{v},ID_{v},S_{v}\}\) to the vehicle via a secure method. In addition, the vehicle generates an initial CRP \((C_{v},R_{v})\) using PUF chips employed on the vehicle, where \(R_{v}=PUF(C_{v})\). Calculate \((P_{Fv},R_{Fv})=Gen(R_{v})\). Then, the vehicle sends the \(R_{Fv}\) to CA via a secure method. Last, \(\{ID_{v},AID_{v},r_{v},y_{v},T_{v},R_{Fv}\}\) is stored in CA's database, \(\{AID_{v},C_{v},P_{Fv},S_{v}\}\) is held by the vehicle.
## 4 Problem Statement and Formulation
### MILP Formulation
#### 4.2.1 Objective  
The main objective of our problem's formulation is to minimize Data Delivery Time (DDT) for each sensor-node as illustrated in the following.  
\[DDT(i)=N_{T}(i,j)+W_{T}(i,j), \tag{7}\]  
\[N_{T}(i,j)=N_{h}(i,j)\times T_{h}. \tag{8}\]where \(i=1,...,n\) and \(j=1,...,m\). \(N_{T}\) stands for the required time for the sensor-node \(i\) to deliver its data to the related RP \(j\) based on number of hops that can be obtained by Equation (9) in which \(N_{h}\) represents the number of hops and \(T_{h}\) is the required time for each hop to process the related information and transfer the data to the next sensor-node. We consider a constant value in \(T_{h}\) for the sensor-nodes since this value is small and roughly same for all of the sensor-nodes. And at last \(W_{T}\) indicates the waiting time for the buffered data which is being sent by the sensor-node \(i\) to the RP \(j\) for delivering to the mobile-sink.  
Compared to the approaches which assume a constant velocity for the mobile-sink to move in the environment [41], we suppose a flexible velocity for the mobile-sink. More precisely, between two consecutive sojourn locations, the mobile-sink can move faster and decrease waiting time or physical obstacles can increase waiting time. We believe considering a constant velocity or predictable velocity for the mobile-sink is suitable for typical WSNs for the purpose of continuous environmental monitoring. Because the sensor-nodes can be informed about the time that the mobile-sink arrives to the sojourn location and adjust data transformation time. However, in EWSNs there is not any pre-information that when an event may occur. Therefore, the movement of mobile-sink might not follow a pre-determined manner and due to some emergency happenings the movement fashion should be changed to decrease the waiting time for improving reliability of the network.  
In addition, the number of sojourn locations has direct influence on reliability and energy-consumption in the network which is hidden in our objective function. Obviously, the ideal scenario for decreasing the waiting time is to specify just one sojourn location in the network. However, this assumption will increase the energy-consumption by communication overhead among the sensor-nodes. Extremely increasing the number of sojourn locations will decrease energy-consumption but it will increase the waiting time. Therefore, our main objective is to find a balanced combination between energy-consumption and reliability in the network by minimizing the data delivery time in Equation (7).
###### Abstract
In this paper, we propose two PA operation schemes: increasing the effective TX power (ITXP) and reducing the PA power consumption (RPC), for the EE improvement in a LS-MIMO-OFDM system with a PAPR reduction technique. Unlike the resource allocation and/or optimization schemes for TX power, we focus on PA operation and connect its operation with TX power. Assuming that the PAPR reduction technique is applied in an appropriate way, depending on the situation, we can choose between two different PA operating modes to effectively improve the EE. The ITXP is the scheme that increases the TX power by maintaining the total power consumption as a constant, while the RPC is a scheme maintains the TX power as a constant by reducing the total power consumption. The closed-form expressions of relative EE for two schemes are derived, and the relative EE of the ITXP scheme is shown to depend on the performance of the precoding method which applied to reduce the inter-user interference (IUI), while that of the RPC scheme is independent of the precoding method. The result of a theoretical analysis and simulation show that the EE performance for both schemes is heavily dependent on the occupation ratio of the PA power consumption over the total power consumption. In what follows, the system model and the proposed schemes are described in Section 2, and the closed-form expression of EE is derived in Section 3. An analysis of the performance and the results of simulation are presented in Section 4, and concluding remarks are given in Section 5.
###### Abstract  
Drip irrigation under plastic mulch is widely used and leads to periodic drying-rewetting (DW) cycles in Xinjiang, Northwest China. However, the effect of different wet and dry alternation types on soil inorganic nitrogen transformation is not clear. Studying these issues not only provides reference for the formulation of fertilization and irrigation systems but is also of great significance for reducing non-point source pollution. An incubation experiment was conducted in 2018 in Baotou Lake farm in Korla City, Xinjiang, with drip-irrigated cotton (_Gossypium hirsutum_ L.). The treatments were designed comprising three parts: (1) DW intensity (Q100, Q90, Q80, Q70, Q60); (2) DW frequency (P3d, P5d, P7d, P9d, P11d); and (3) soil wetting time (P1m, P3m, P5m). The results revealed that the contents of the NH\({}_{4}\)\({}^{+}\) and NO\({}_{3}\)\({}^{-}\) decreased with the increase in the DW intensity and were highest in the Q100 treatment. The rate of net N mineralization decreased with the increase in the DW intensity. The highest rate (P.02 mg kg\({}^{-1}\) d\({}^{-1}\)) was found in the Q70 treatment in the wet to dry process and 3.03 mg kg\({}^{-1}\) d\({}^{-1}\) in the Q60 treatment in the dry to wet process, respectively. The contents of the NH\({}_{4}\)\({}^{+}\) and NO\({}_{3}\)\({}^{-}\) were higher with the higher DW frequency (P3d). The rate of net N mineralization decreased with the increase in the DW frequency and was highest in the P3d treatment in the wet to dry process, respectively. The soil wetting time was longer with the content of NH\({}_{4}\)\({}^{+}\), NO\({}_{3}\)\({}^{-}\), and N mineralization (P5m). The rate of net N mineralization was higher with the longer soil wetting time in the wet to dry process and the shorter soil wetting time from the dry to wet process. These results demonstrate that a reasonable DW intensity, DW frequency, and soil wetting time could not only effectively promote nitrogen transformation and the absorption of nitrogen but also reduce the nitrogen losses under drip irrigation.  
frequency; intensity; mineralization; transformation; wetting time +
Footnote †: journal: Applied Sciences
# Mapping Server Collaboration Architecture Design with OpenVSLAM for Mobile Devices
## 1 Introduction
In this paper, we propose a design method for an AR system that can be used in mobile devices or augmented reality headsets through a markerless-based SLAM algorithm. For the implementation of the mobile SLAM system, OpenVSLAM, which can save and load the generated maps among various open-source SLAMs and provides web visualization functions, was chosen. In consideration of real-time performance and scalability, the stand-alone type, which independently performs SLAM on a mobile device, and the mapping server type, which receives the result of SLAM from the server and processes only the visualization for the purpose of not adding to the SLAM operation overhead on the mobile device, were designed at the same time. Through the dualization of SLAM performance, users can continuously track their location along with a map generated in advance for the indoor/outdoor environment they are looking at and are able to build a service that can provide AR contents based on a more accurate location. To enable the development of visual-slam-based AR applications in a mobile environment, Unity, which is widely used as a visualization engine for Android apps, was applied to evaluate the performance of the slam system. To verify the function and the performance of the mobile SLAM system proposed in this paper, comparisons between the stand-alone type and mapping server type were made on desktops and mobile devices using the EuRoC datasets, and the abilities for each type to generate maps in real environments were evaluated. The remainder of this paper is organized as follows. In the following section, we describe the related works on various SLAM methods. In Section 3, the OpenVSLAM-based mobile SLAM system structure and main functions are described. In Section 4, we evaluate the results of map creation and visualization and localization accuracy using real mobile devices. Finally, we provide our conclusions in Section 5.
# Maximizing the Capacity of Edge Networks with Multicasting
## 7 Multicast Network Capacity  
### Content Caching Algorithm  
The aforementioned confirms that an efficient content caching algorithm is also important for improving the system's performance. This is mainly because this study adopts the multicast transmission scheme and the collaborative distance between the SBS transferring the requested caching content to the SBS that received the request plays a key role in system capacity. An intuition is to place one copy in each subarea of the network to minimize the transmission distance. This is the proportional regional caching (PRC) algorithm. Specifically, first divide the SBS in the entire network into \(C_{i}\) subareas (lines 3-5), and then store each copy in the \(C_{i}\) subareas (lines 6-11). After that, the number of copies for the \(i\)-th content is reduced (line 12) as shown in Algorithm 1. When one copy is cached in one subarea, random caching is performed for the remaining copies.  
```
1:The nodes are distributed according to the Poisson point process and the intensity is \(\lambda_{e}\). The users are distributed according to the Poisson point process and the intensity is \(\lambda_{u}\).
2:for\(i=1\) to \(m\)do
3: All SBSs are divided into \(C_{i}\) subareas
4: Select \(C_{i}-1\) cell randomly, and the number of SBSs in these cells is \(ceil\)\((n/C_{i})\)
5: Divide the remaining SBSs into the last cell
6:for\(t=1\) to \(C_{i}\)do
7: Randomly select an SBS \(j\) from cell \(t\)
8:while the cache size \(s_{j}\) is equal to 0 do
9: Select another SBS randomly from the cell node
10:endwhile
11: Store content \(i\) into \(SBS_{j}\)
12:\(c_{i}\gets c_{i}-1\)
13:endfor
14:endfor
```  
**Algorithm 1** The proportional regional caching algorithm
# Fourier Transform (FT) Analysis of the Stress as a Tool to Follow the Fatigue Behavior of Metals
## 4 Fourier Spectrum  
To investigate the mechanical nonlinear behavior of metallic specimens, cyclic tests were performed at a given strain amplitude and the force response was analyzed via FT. Figure 2 presents the FT spectra of the materials at \(\varepsilon_{0}=0.4\%\) (\(R=0.1\), \(\varepsilon_{max}=0.89\%\)) and \(\omega_{1}/2\pi=5\) Hz. The spectra show a good signal to noise ratio in the range of 10\({}^{4}\):1, so that the measured higher harmonics can be seen as quantification of a nonlinear material response. Beside the fundamental harmonic at 5 Hz, the FT spectra show also higher harmonics at 10 Hz, 15 Hz, etc., clearly indicating nonlinear material behavior. It is interesting to note that the even higher harmonics, such as \(I_{2/1}\), \(I_{4/1}\), etc. (at 10 Hz, 20 Hz, etc.), have lower intensities as the odd ones \(I_{3/1}\), \(I_{5/1}\), etc. (15 Hz, 25 Hz, etc.), so the nonlinear symmetric contribution in the material response exceeds the nonlinear asymmetric one.  
Figure 1: Tensile stress-strain curve (3 mm/min) for CRS, AL and brass showing a nonlinear material behavior (deviation from [PERSON]’s law) above \(\varepsilon=0.5\%\).
## 3 An Efficient Speech CBSS Algorithm in Multipath Channels
### Fast IVA Algorithm
The symmetric decorrelation is calculated as:  
\[w_{i}^{(k)}\leftarrow\biggl{(}w_{i}^{(k)}\Bigl{(}w_{i}^{(k)}\Bigr{)}^{\mathrm{ H}}\biggr{)}^{-1/2}w_{i}^{(k)}. \tag{12}\]In the algorithm, in order to avoid local optimal solutions, we use the unit matrix as the initial demixing matrix in all frequency points. It can be seen from the derivation process of the algorithm that demixing matrix has no orthogonality constraints and does not produce separation error accumulation, which ingeniously solves the permutation ambiguity in the frequency-domain algorithm. We introduce a Taylor series to optimize the contrast function in the optimization algorithm, which makes it possible to obtain the optimal solution quickly in the iterative update of the separation matrix, simplify the iterative update process and reduce the computational complexity of the algorithm. The specific implementation steps of the core algorithm in this paper are as follows in Algorithm 1. ```
Step 1: Transform the time-domain convolutional mixed signal by STFT into a complex-valued signal at each frequency point in the complex frequency domain; Step 2: Centralize and pre-process the mixed signal at each frequency point; Step 3: Initialize the demixing matrix \(w_{0}^{(k)}\) for each frequency point; Step 4: Estimate the separated signal \(y_{i}^{(k)}\) according to Equation (6); Step 5: Calculate and optimize the contrast function and nonlinear function based on the estimated source signal; Step 6: Update the demixing matrix \(w_{i}^{(k)}\) according to Equation (11); Step 7: Decorrelation of the demixing matrix according to Equation (12); Step 8: Normalize the separation matrix to resolve the amplitude uncertainty of the separated sub-signals; Step 9: Determine whether the separation matrix converges, and if it converges, execute step 11; Step 10: If the maximum number of iterations is reached, output the final separated signal at each frequency point, otherwise return to step 4; Step 11: Restore the separated signal of each frequency point into a time-domain separated signal by ISTFT; that is, extract the source speech signal. ```  
**Algorithm 1**CBSS based on Fast IVA algorithm