esa-sceva/satcom-chunk-collection huggingface dataset:
# SDN-Based Routing for Backhauling in Ultra-Dense Networks
###### Abstract  
Ultra-Dense Network (UDN) deployment is considered a key element to achieve the requested capacity in future fifth-generation (5G) mobile networks. Backhaul networks in UDNs are formed by heterogeneous links with multi-hop connections and must handle massive traffic. Backhauling in future 5G networks may represent the capacity bottleneck. Therefore, there is the need for efficient and flexible routing schemes able to handle the dynamism of the traffic load in capacity-limited networks. Toward this goal, the emerging Software-Defined Network (SDN) paradigm provides an efficient solution, transferring the routing operation from the data plane switches to a central controller, thus achieving more flexibility, efficiency, and faster convergence time in comparison to conventional networks. This paper proposes and investigates an SDN-approach for an efficient routing in a capacity-limited backhaul network that carries data and control traffic of a heterogeneous UDN. The routing algorithm is centralized in the SDN controller and two different types of traffic flow are considered: data and control plane coordination traffic. The goal is to reduce or even to avoid the amount of traffic that the backhaul network is not able to support, distributing in a fair way the eventual lack of bandwidth among different access points. Simulation results show that with the considered approach the performance significantly improves, especially when there is an excess of traffic load in the network. Moreover, thanks to the SDN-based design, the network can reconfigure the traffic routing depending on the changing conditions.  
5G; software-defined network; backhaul routing; ultra-dense networks +
Footnote †: journal: Sensors
## 6 Results
### Trust Threshold-Based Selection Mode
#### 6.1.1 Results Using Trust Threshold 30%
Thus, it is harder for routers to find various forwarding possibilities. Consequently, despite the routing scheme, the results will be the same. Epidemic shows that privacy-aware routing versions generate 40% with a small network size. It reaches 60% with medium size, then slows down with larger size. We explain this behavior by the large space and longer amount of time used by the working day model. Thus, it will be more difficult to find candidates' nodes able to fulfill the selection method for privacy preservation. Figure 3: The result of trust threshold 30% and random way movement model. The enhancement increases with medium-sized networks (65% for 160-sized networks), but when the number of hosts overpasses 160 nodes and a threshold (30%), intermediary routers select more hosts with low relation scores, which decreases privacy enhancement. This is also true for Prophet and Spray and Wait protocols. For all of them, the network efficiency is lightly affected.
# Data Compression with a Time Limit
## 2 Data Compression with a Time Limit  
The compression process, especially in the case of large databases, is characterized by a trade-off between time and space that the user must be aware of and on which they must make a decision. There are various compression algorithms that allow you to optimize the degree of compression, or the time needed for this process.  
Individual compression algorithms often also allow a more fine-grained choice by specifying a compression level, where a low level represents the desire for a minimum required time, while a high level represents the need for maximum compressibility of the supplied document.  
With the advent of cloud computing and the service-based and pay-per-use model widely used nowadays, one can easily imagine the need to be able to set a specific time budget for a certain activity such as data compression. As specific activities, one can imagine the creation of hourly or event-related dumps. A concrete case specific to cloud computing can be imagined by considering the _FaaS_ (\"Function as a Service\") model.  
The cost of this model is directly proportional to the number of calls performed and, in particular, to the duration of each.
# Seismic Performance Evaluation of Highway Bridges under Scour and Chloride Ion Corrosion
###### Abstract  
Cross-river bridges located in seismically active areas are exposed to two major natural hazards, namely earthquakes and flooding. As the scour depth increases, more parts of the bridge substructure will inevitably be exposed to unfavorable conditions such as chloride ion (Cl\({}^{-}\)) corrosion. To investigate the seismic performance of highway bridges under the action of scour and Cl\({}^{-}\) corrosion, a spatial finite element dynamic model of a continuous rigid bridge was established and a Cl\({}^{-}\)-accelerated electrochemical corrosion test and quasi-static test were carried out. The results showed that a reasonable scour depth and the combination sub-factors under the joint probability density of scour action and seismic action can be obtained to establish the combined expression of the action effect. Cl\({}^{-}\) corrosion can cause a reduction in displacement ductility, load-bearing, and energy dissipation capacity, and increase inequivalent viscous damping coefficient of the columns. Seismic damage of the columns grows linearly to twice the ultimate displacement under Cl\({}^{-}\) corrosion, which becomes more significant with the increase of the reinforcement ratio.  
bridge engineering; earthquake; scour; chloride ion erosion; load combination; partial factor; damage mode +
Footnote †: journal: Applied sciences
## 5 Conclusions  
The purpose of this study was to determine whether data based on multiple relative azimuth angles can improve the accuracy of prediction models for soluble solids content and moisture content of jujube fruit. The results of this study indicate that data at different relative azimuth angles have different effects on model recognition accuracy and that using multispectral data at multiple relative azimuth angles as input yielded better predictions for the MC and SSC of jujube fruit compared to using multispectral data at a single relative azimuth angle as input. This study provides us with a way to improve model accuracy in UAV multispectral detection technology. The assessment of jujube fruit quality should not solely rely on MC and SSC. Future research should investigate the predictive capabilities of this method on additional indicators like hardness and vitamin C.  
Conceptualization, X.M. and H.L.; methodology, C.W.; software, C.W. and X.M.; validation, G.G. and H.L.; formal analysis, G.G.; investigation, X.M.; resources, H.L.; data curation, C.W.; writing--original draft preparation, C.W. and X.M.; writing--review and editing, X.M. and G.G.; visualization, X.M.; supervision, H.L. and C.W.; project administration, H.L. and X.M.; funding acquisition, X.M. and G.G. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was supported by the Open Project of Xinjiang Production & Construction Corps Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin (BRYB2303), the National Natural Science Foundation of China (11964030), Tarim University President's Fund Project (TDZKSS202306), and the Open Project of Key Laboratory of Modern Agricultural Engineering in Colleges and Universities of the Department of Education of the Autonomous Region (TDNG2021201).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data presented in this study are available on request from the corresponding author.  
**Acknowledgments:** The authors sincerely thank the anonymous reviewers for their critical comments and suggestions for improving the manuscript.  
**Conflicts of Interest:** The authors declare no conflicts of interest.
# Development and Research of a Medium Vertical Dipole Electromagnetic Pulse Simulator
## 3 Design and Construction  
Regardless of the form of the EMP simulator, it mainly consists of two parts: an antenna serving as an electromagnetic energy emission unit and a pulsed power driver serving as an energy supply unit. The working process of the entire device is as follows: the pulsed power driver compresses the slowly charged electric energy into a high-voltage fast pulse in the nanosecond range, which is then fed into the antenna through a connecting port. The antenna converts the electrical pulse into an electromagnetic wave and radiates it outward, forming an EMP environment for experiments.  
Taking into account the impact of the surrounding environment on the radiation field, the inverted cone antenna used in the dipole-type EMP simulator is usually built in open areas outdoors and requires a nonconductive support structure to hold it up. Due to environmental factors such as wind, rain, and snow, a wire grid structure, as shown in Figure 1b, is commonly used. When the electromagnetic waves propagate to the top of the inverted cone antenna, reflection occurs. To minimize the impact of reflected waves on the test environment, resistive loading is often applied to the antenna cable to dissipate excess energy.  
Based on the above principles, a medium-sized vertical polarized dipole EMP simulator was designed in this paper. The antenna structure is shown in Figure 2, which adopts an inverted cone structure, using the ground as the mirror plane, with a height of  
Figure 1: The structure of a dipole EMP simulator with the ground as the conductive plane. (**a**) Voltage feed-in over the ground. (**b**) Voltage feed-in under the ground.  
5 m, a half-cone angle of 32\({}^{\circ}\), and an impedance of 75 \(\Omega\). The layout of the driving source also adopts two forms, as shown in Figure 1. In the following figure, Figure 2a shows the pulse-voltage top feed mode layout of the simulator, while Figure 2b shows the bottom feed mode layout. In the top feed mode, a one-stage compression circuit consisting of a Marx generator and a peak capacitor is used as the pulse source. For the bottom feed mode, the pulse source is composed of a Marx circuit based on an avalanche tube and a coaxial cable with an impedance of 50 \(\Omega\).
## 5 Methodology
### Metrics
#### 5.3.2 Spectral Efficiency  
The spectral efficiency, a measure of the performance of channel encoding to utilize bandwidth (\(BW\)) efficiently, was defined as the average number of bits per unit of time that could be transmitted per unit of bandwidth [bits/s/Hz]. The spectral efficiency (\(\eta\)) for the particular n-pulse modulation used was approximate as follows:  
\[\eta=\frac{R_{\text{b}}}{BW} \tag{6}\]  
where \(R_{\text{b}}\) is the bit rate, also expressed as \((1/T_{\text{b}})=(\log_{2}M/T_{\text{s}})\) and \(BW\) is the bandwidth that can be represented as \(M/(D\cdot T_{\text{s}})\). Therefore, the bandwidth efficiency is given by  
\[\eta=\text{min}(D,1-D)\cdot\frac{\log_{2}M}{M} \tag{7}\]
# Numerical Simulation Study on the Performance of Buried Pipelines under the Action of Faults
## 2 Finite Element Model of Pipe-Soil System  
In this study, the structural response of pipelines under fault movement is examined numerically using the finite element program ABAQUS [23]. Considering the nonlinear geometric shapes of soil and pipelines, the mechanical behavior of steel pipes, the surrounding soil, and their interactions is rigorously simulated by describing the large strain of the pipeline soil system and the inelastic material behavior of the pipeline and soil.
# Remote Sensing of Ecosystem Water Use Efficiency in Different Ecozones of the North China Plain
## 2 Data and Methods
### Methods
#### 2.3.4 Correlation Analysis  
The Pearson correlation coefficient between WUE and climatic factors is calculated as follows:  
\[Cor=\frac{\sum{(m-\overline{m})(n-\overline{n})}}{\sqrt{\sum{(m-\overline{m})^ {2}\sum{(n-\overline{n})^{2}}}}} \tag{5}\]  
where \(Cor\) icoefficient, m is the climate factor sequence (precipitation and temperature), and n is the ecosystem WUE sequence. The significance of WUE and climatic factors was tested using a t-test.  
\[\text{t}=\frac{Cor\sqrt{q-2}}{\sqrt{1-Cor^{2}}} \tag{6}\]  
The t-distribution of degrees of freedom q \(-\) 2 was followed, given a significance level \(\alpha\)1 (\(p<0.05\)). If t \(>\) t\({}_{\alpha 1}\), the original hypothesis is not valid, and the correlation coefficient is considered significant.  
Figure 2: Overall technical flowchart.
# Reverse Electrodialysis: Potential Reduction in Energy and Emissions of Desalination
## Appendix C SWRO Desalination Plants' Specifications  
The RED plant retrieves energy from the rejected brine of the high pressure (HP) RO pass (HC feed RED, Figure 11) paired with the optimal diluate feed stream of the RED stack. To estimate the concentration and flow rate of the HP RO pass' concentrate effluent (not directly disclosed in some scenarios), we set out mass balances for each SWRO plant considering the following reported data (i) the overall RO configuration, (ii) the water recovery rate RR and (iii) the salinity of final permeate and feed seawater.  
Figure 11 depicts the simplified scheme of some RO configurations given in Table 11. In a single-pass two-stage RO configuration (1P and 2S Figure 12a), the concentrate effluent of the 1 st RO stage or pass is further treated in a 2 nd RO stage to enhance the overall water recovery rate and final permeate's quality. The permeate of the 1 st and 2 nd RO stages makes up the final permeate of the SWRO plant. In a partial two-pass RO system (P2P, Figure 12b), a portion of the 1 st RO pass' permeate is further treated in a 2 nd RO pass, while the remaining permeate effluent is directly blended with the permeate produced by the 2 nd RO pass. The 2 nd RO pass' concentrate effluent is returned to the 1 st pass feed to enhance the overall water recovery rate. In a four-stage cascade configuration (C, Figure 12c), the 1 st and 2 nd RO stages comprise the Split-Partial Second Pass stage (SP2P), which is an advance partial-two pass RO design. In an SP2P configuration, the permeate produced by the rear elements of the 1 st RO pass' pressure vessel is further polished in a 2 nd RO pass (the second pass treats a smaller, but more saline stream than a conventional partial two-pass system), and the permeate produced by the front elements of the 1 st RO pass' pressure vessel is directly blended with the 2 nd and 4 th RO stage permeate. The 3 rd and 4 th RO stages comprise the conventional full two-pass (F2P) RO stage that processes the 2 nd RO pass' concentrate effluent of the SP2P stage. The 3 rd RO permeate effluent is sent to the last stage (4 th RO stage) of the plant.  
Figure 12: Overall RO configuration of some SWRO desalination plants: (**a**) Single-pass (1P) with a two-stage configuration (2S); (**b**) Generic partial two-pass (P2P); (**c**) Split partial two-pass (SP2P) with a four-stage cascade configuration (C). High pressure RO pass (HP, **); Low pressure RO pass (LP, **). The RED plant recovers energy from HP RO pass’ concentrate effluent (HC feed RED).
## 5 Results
### Throughput  
Network throughput is an important metric to evaluate routing protocols. Throughput refers to the packets that are eventually transmitted to the base station in the network. In clustering protocols, ordinary nodes send the data they observe to the corresponding cluster-heads. The cluster-head fuses the received data and transmits the packets to the base station after a series of relay. As the network runs, the number of alive nodes in the network decreases, and the packets sent to the base station gradually decrease until the last node dies. The throughput then reaches its maximum value. The higher the throughput, the more effectively information is collected from the surrounding environment, and the better the performance of the protocols.  
Figure 7a-c show the performance of LEACH, K-LEACH, IEECHS-WSN, RCH-LEACH, and DCK-LEACH in terms of the throughput in all scenarios. In Scenario 1, as shown in Figure 7a, the throughput of DCK-LEACH algorithm is up to \(2.5\times 10^{5}\), and the throughput of the LEACH, K-LEACH, IEECHS-WSN, and RCH-LEACH algorithms are, respectively, \(0.9\times 10^{5}\), \(1.4\times 10^{5}\), \(2.3\times 10^{5}\), and \(1.25\times 10^{5}\). Compared with the other four algorithms, its throughput is improved by 170%, 79%, 8%, and 100%. In the other two scenarios, as shown in Figure 7b,c, DCK-LEACH is superior to LEACH, K-LEACH, IEECHS-WSN, and RCH-LEACH in terms of throughput. This indicates that the higher throughput among them is DCK-LEACH and IEECHS-WSN.  
Figure 6: Comparison residual energy of the network in three scenarios: (**a**) 100 nodes, (**b**) 200 nodes, (**c**) 300 nodes.  
This is because the two algorithms propose the double cluster-heads policies in routing. In addition, the DCK-LEACH algorithm also optimizes in terms of energy evenly distributed, so its network lifetime is longer than that of IEECHS-WSN, therefore, its throughput is slightly higher than that of the IEECHS-WSN algorithm. The cooperation mode of the dual cluster-heads can greatly prolong the survival time of a single cluster-head  
Figure 7: Comparison throughput of the network in three scenarios: (**a**) 100 nodes, (**b**) 200 nodes, (**c**) 300 nodes.  
in a cluster, so sensors can collect more packets and send them to the base station. As a result, its throughput has also been greatly improved.
# Scaling of Rain Attenuation Models: A Survey
## 5 Research Scopes and Challenges
### Synthetic Storm Approach-Based Elevation Angle Scaling  
In [24], the SSA-based time series generation scaling techniques were proposed. An improved version of the SSA method was proposed in [61], which improved the performance over the conventional SSA technique. The characteristics can be retrieved from additional sources using this improved SSA approach, including a discriminating mechanism for distinguishing between stratiform and convective rain episodes. Consequently, there are research scopes to apply this improved version of the SSA technique for elevation scaling through rain attenuation time series.
## 4 Discussion and Conclusions
### Conclusions  
While demonstrated multiple times by DARPA/NASA and the USN, a UA that has achieved Initial Operational Capability (IOC), capable of conducting A3R, does not exist as of time of this publication. Extensive research has been conducted on different aspects of the missions, such as DGPS for close formation flying and CV for object detection within the domain. As technologies advance, new sensors bring additional capabilities that were not available during previous demonstrations. In this paper, a discussion of the sensors required to complete the different phases of A3R was covered, and they are shown in Figure 14. These sensors, and a summary of their purpose, the phase in which they are used, and the frequency band they utilize, are also summarized in Table 1 below. The phases listed in Table 1 correlate with the phases shown in Figure 14.  
As discussed in Section 3, the sensor requirements (e.g., transmit and receive (T&R) capability or receive (R) capability) and the anticipated frequency band of the sensor will provide valuable insight into the SWaP-C required to implement that capability. Many of the sensors listed in Table 1 overlap in frequency band, such as the airborne data link between UA to UA and the GNSS receiver. In these cases, resource simulations will be required to determine if the receiver system (aperture, radio, etc.) has the required resources to manage multiple requirements.  
In conclusion, all sensors required to complete A3R are available as of the date of this publication. There are numerous benefits from A3R, and the future of military and commercial aviation will necessitate that UAs become capable of completing A3R. This paper introduces and reviews the sensors required for a UA to complete A3R. Suggested future research to support A3R includes the deployment of scaled models, demonstrations of the application of sensors to accomplish the tasks and phases required for A3R, and the investigation of new sensor technologies to support A3R requirements.  
Figure 14: Review of the sensor requirements by phase of flight.  
**Author Contributions:** Conceptualization, S.H. and J.P.; writing--original draft preparation and revisions, J.P.; and writing--review, revisions, and editing, S.H. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This paper was supported by research that received funding from the Department of Defense, Award N00014-22-1-2526.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Not applicable.  
**Acknowledgments:** The authors would like to thank [PERSON] for her assistance in providing the aircraft silhouettes used in many of the figures. Additionally, the authors would like to thank (in alphabetical order) [PERSON], [PERSON], and [PERSON] for their review of and recommendations for this paper. [PERSON] would like to thank his loving wife for her continued support.  
**Conflicts of Interest:** The authors declare no conflict of interest.
# An Active-Clamp Forward Inverter Featuring Soft Switching and Electrical Isolation
###### Abstract  
Traditional photovoltaic (PV) grid-connection inverters with sinusoidal pulse-width modulation (SPWM) control suffer the problem of buck-typed conversion. Additional line-frequency transformers or boost converters are required to step-up output voltage, leading to low system efficiency and high circuit complexity. Therefore, many flyback inverters with electrical isolation have been proposed by adopting a flyback converter to generate a rectified sine wave, and then connecting with a bridge unfolder to control polarity. However, all energy of a flyback inverter must be temporarily stored in the magnetizing inductor of transformer so that the efficiency and the out power are limited. This paper presents a high-efficiency active-clamp forward inverter with the features of zero-voltage switching (ZVS) and electrical isolation. The proposed inverter circuit is formed by adopting a forward converter to generate a rectified sine wave, and combining with the active-clamp circuit to reset the residual magnetic flux of the transformer. Due to the boost capability of the transformer, this inverter is suitable for the PV grid-connection power systems with wide input-voltage variation. The operation principles at steady-state are analyzed, and the mathematical equations for circuit design are conducted. Finally, a laboratory prototype is built as an illustration example according to proper analysis and design. Based on the experimental results, the feasibility and satisfactory performance of the proposed inverter circuit are verified.  
photovoltaic (PV); inverter; active-clamp; zero voltage switching (ZVS); grid-connection +
Footnote †: journal: Applied Sciences