esa-sceva/satcom-chunk-collection huggingface dataset:
# Free-Space QKD with Modulating Retroreflectors Based on the B92 Protocol
###### Abstract  
Free-space quantum key distribution (QKD) has attracted considerable attention due to its lower channel loss and link flexibility. It allows two participants share theoretical unconditional secure keys, and can potentially be applied to air-to-ground quantum communication to establish a global quantum network. Free-space QKD using modulating retro-reflectors (MRR-QKD) significantly reduces the pointing requirement and simplifies the structure of the mobile terminal, therefore making it suitable for lightweight aircraft such as unmanned aerial vehicle and Cubesat, etc. Based on intensity modulation of two non-orthogonal states and the B92 protocol, we proposed a scheme to improve the previous work (_Optics Express_**2018**, _26_, 11331). Our scheme simplifies the optical structure and shows more robustness in equipment imperfection. The analysis and simulation show that the number of multiple quantum well modulators needed in our scheme decreases from eight to three with similar performance. Additionally, while the previous scheme cannot work due to low modulator extinction ratio or high optical misalignment, our scheme can still operate.  
quantum key distribution; free-space; modulating retroreflector; B92 protocol Article
# Performance and Evaluation of GNSS Receiver Vector Tracking Loop Based on Adaptive Cascade Filter
## 3 Experiment and Analysis
### Kinematic Test under Signal Blocking or Interference Occasions  
Considering extreme scenarios, when the satellite signal is weak or less than or equal to four satellites, this section performs an interrupt processing on GNSS IF signals and presents the positioning results of different methods under satellite interference conditions. The parameter settings are shown in Table 4.  
The signals with satellite numbers 16 and 28 are interrupted for different time periods. Figure 8 shows the signal mean square value of the prompt IQ branch. In the corresponding signal interruption interval, the value of the traditional method is obviously reduced, and the Doppler frequency shift is also abrupt in Figure 9. The proposed method corrects the code loop and the carrier tracking loop through the pseudo-range and pseudo-range rate fed back by the navigation solution module, and maintains the same accuracy as when the signal is visible. The C/N\({}_{0}\) values of different channels of satellite signals are presented in Figure 10. In the absence of a signal, the C/N\({}_{0}\) of the traditional tracking method drops rapidly, and cannot be restored when the signal returns to normal. The C/N\({}_{0}\) of the proposed method basically remains stable. This is precisely because the channels of the traditional method are independent of each other and cannot realize the sharing and assistance of information, which causes the signal to easily lose lock. The proposed method uses the navigation filter module to unify the code phase error and the carrier frequency error as the measurement, and performs the filter estimation, which can realize the complementarity between the channels and improve the stability and accuracy of the system navigation and positioning. This can also be observed in Figure 11. After 50 s, due to the influence of signal interruption, the positioning results calculated by traditional methods gradually diverge, or even cannot be completed. The proposed method can still  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Satellite PRN** & **Signal Interruption Time** \\ \hline
16 & 50s–70s, 80s–90s \\
28 & 80s–90s \\ \hline \hline \end{tabular}
\end{table}
Table 4: Signal interruption time and satellite Pseudo Random Noise(PRN) code setting.  
Figure 7: Comparison result of position error in the kinematic test.
## 1 Introduction
### Related Work
A DNN with multiple convolutional layers is utilized to represent the state, and features are extracted from a high-dimensional input containing CSI and cache states. The challenge lies in finding the optimal offloading and resource allocation decisions, often formulated as a mixed-integer non-linear programming (MINLP) problem, which is NP-hard, in general [24]. Different approaches have been proposed to solve this problem, such as differentiable optimization techniques, metaheuristic algorithms, and DRL methods. Differentiable optimization techniques use gradient-based methods to find the optimal solution. However, they require the objective function and constraints to be differentiable, which may not be the case for some MEC scenarios [25]. Metaheuristic algorithms are stochastic optimization methods that explore the search space using various operators, such as mutation, crossover, and selection. They can handle complex and non-linear problems but may suffer from slow convergence and high computational complexity [26; 27]. Most existing works mainly focus on dual-layer computation offloading. However, the demand for computation offloading is rapidly increasing in the connected IoT domain. Therefore, this paper evaluated the multi-layer computation offloading scheme in MECNs to fill the gap. Furthermore, to suppress the energy and delay, a state-of-the-art DRL-A3C multi-agent-based learning approach was exploited in this work. The A3C algorithm leverages a collaborative setup involving a global network and multiple agents, making it an advanced tool for real-time learning and complex problem-solving. Particularly in scenarios involving the non-convex MINLFP problem in dynamic and dense wireless environments, the A3C algorithm demonstrates its suitability and practicality [28].
## 2 Protocols for Synchrotron X-Ray Experiments  
Achieving high-quality experimental data in FC-BENTEN hinges on the implementation of standardized protocols that ensure consistency, reproducibility, and traceability across all stages of the synchrotron X-ray experiments, from sample preparation to data analysis. To meet these objectives, beamlines tailored to specific measurement techniques, such as XAFS, HAXPES, XRD, PDF, and SAXS, were strategically selected. For example, although BL08W offers higher detector sensitivity for PDF measurements, its frequent reconfigurations can lead to calibration variability; thus, BL04B2 emerges as the preferred choice because of its stable setup.  
To enhance reproducibility and minimize variability, critical protocol steps were meticulously documented as metadata. These metadata enable tracking and integration of experimental conditions and serve as the backbone for cross-disciplinary data utilization. Detailed online manuals in web-based format, developed using Markdown [6], provide standardized workflows that are accessible, user-friendly, and regularly updated. Robust authentication and authorization mechanisms ensure secure access, safeguard sensitive information, and promote responsible use.  
This approach reduces inconsistencies from individual practices and supports reliable generation of high-quality data. The protocols cover key aspects, such as sample preparation, measurement techniques, and data processing workflows, with details on metadata design, data registration, and database integration provided in subsequent sections.  
\begin{table}
\begin{tabular}{c c c c} \hline
**Measurement Technique** & **Beamlines** & **Instruments** & **Information Obtained** \\ \hline HAXPES & BL46 XU, BL09 XU & & Electronic state, d-band center \\ \hline XRD & BL19B2 & & Crystal structure, Degree of alloying \\ \hline PDF & BL04B2 & & Amorphous structure, Particle size \\ \hline SAXS & BL40B2 & & Average particle size, Distribution \\ \hline \end{tabular}
\end{table}
Table 1: _Cont._
#### Brief History of the BeSYC Software  
The idea to develop the BeSYC software started from a _simple_ attempt to create a MATLAB script to apply the numerical framework related to the BEPU methodology in the post-test numerical analysis of an experimental campaign carried out at KIT [8]. However, since the early stage of development, it was noted that most of the efforts to apply the BEPU methodology would have been needed while writing the input decks required for the several code runs (the so-called _sensitivity input decks_). The execution of such code runs was also found to be a task requiring a relevant effort because the manual starting of more than 100 runs would have meant the presence of dead times between a run and the following. Not only this, but these tasks are also prone to human errors, especially considering the typical iterative process of \"tuning and error fixing\" of the input decks based on the achieved results.  
For these reasons, the development of this simple script turned into the development of a much more complex tool capable of managing all these complex aspects. The development of the BeSYC software was grounded on three fundamental pillars: _independency_, _modularity_, and _multi-platform availability_:  
* _Independency_ because the tool is developed independently from any system code;
* _Modularity_ since it is developed following a modular approach capable to ease the maintenance of the code itself and the introduction of new features;
* _Multi-platform availability_ in view of the fact that the tool should run on each operative system for which the system code executables are available (Microsoft Windows(r) 7, 10, and 11 and Linux).  
A further impulse to the development of BeSYC came when the number of options to run the BEPU methodology started to increase, i.e., when also the \(C_{\alpha\alpha}\) and \(C_{\alpha r}\) variance-covariance matrices started to be given as input data (see Section 2). This necessity pushed for the development of a Graphical User Interface (GUI) capable to guide the user into the creation of the BeSYC _input files_. In the same frame of time, the BeSYC software was also improved with the possibility to write and run a _best-estimate input deck_ (for the system code in use) after the application of the BEPU methodology.
## 2 Multi-Criteria Model of Temporary Facility Layout Planning in Construction
### Identification of Layout Factors and Objectives  
In order to formulate a generic temporary facility layout planning model, it is critical to identify and define all relevant planning objectives and criteria involved in the planning and decision process. Based on the previous research and studies, the critical factors that influence the main objectives can be identified. Table 1 presents the list of the related criteria and sub-criteria that significantly impact temporary facility layout planning, which can be summarized as follows:  
* safety criterion: including proper equipment operation (PEO), control of hazardous zones (CHZ), control of hazardous material (CHM), minimization of the total number of intersections (TNI) and safety of task execution (STE);
* productivity criterion: including effective space utilization (ESU), labor productivity and ergonomics (LPE), short construction duration (SCD), the ability to dynamically change the temporary facilities (ACT), facility closeness relationships (FCRs) and workspace conflicts (WSC);
* cost criterion: including facility setup cost (FSC), facility removal cost (FRC), resource travelling cost (RTC), resource handling cost (RHC) and worksite personnel visit cost (WPC).
# Hybrid VLC-RF Channel Estimation for GFDM Wireless Sensor Networks Using Tree-Based Regressor
## 5 Performance Metrics
### Bit Error Rate (BER)  
The Bit Error Rate (BER) indicates the ratio of incorrectly predicted bits (errors) to the total number of transmitted bits across the dataset. It is given by  
\[\text{BER}=\frac{\text{Number of Bit Errors}}{\text{Total Number of Transmitted Bits}}. \tag{24}\]
## 4 Discussion
The major assets of active buildings are renewable energy resources sustained by photovoltaic, wind turbines, heat pumps, feeding energy into batteries (static and mobile ones in electric vehicles), to name a few. All these devices are controlled by managerial systems that timely detect shifts in supply/demand to adapt power accordingly. We address here the cybersecurity components in place that are required to keep these active buildings as cyber-physical resilient as possible. Adversaries have a huge attack surface to consider when willing to compromise it where they may attack not only the physical infrastructure but also tweak the flexible controls in place. This could increase the chances of relying on the conventional power grid to meet electricity demand instead of the localised features offered by active buildings. In the ever-changing threat landscape and the ubiquitous use of cloud-based architectures in the SG, smart buildings, and almost any CPS with IoT, a few measures should be taken into account such as: \begin{tabular}{l p{284.5 pt}}
**Sharing issues** & organisations have reasons for not sharing CTI, i.e., privacy, confidentiality, data related issues and protection. There are clear advantages on sharing, however, and industry and academia must discuss advantages and propose new ways of promoting it, through incentives or showing that protective measures do enhance overall cyber-defences. \\
**Update obsolescence** & as the cyber-attack unfolds and gets reported, new venues are explored by adversaries, so older reporting may become outdated. \\
**Timeliness** & offer updated indicators of compromise given emergence of new threats and highly sophisticated cyber-attacks. \\
**Structured formats** & there is a need for standardised ways of communicating threats, vulnerabilities, and attacks, also on simplified reporting when depicting and learning about malicious incursions. \\
**Trustfulness** & peers exchanging newest attacks in standardised fashion. \\
**Model management** & cybersecurity officers already have a lot of work deterring cyber-attackers, and modelling should not hinder their activities or impact their productivity. Instead, it should help them and guide better analysis and quick responses. \\ \end{tabular}   
**Cognitive load**: the magnitude and breadth of data available for analysts could act as the cause for impairing better judgements, given the number of new variables to consider. CTI should offer a minimum set of data points so stakeholders are not overwhelmed by it. **Scalability**: concerns on emergence of new devices in the infrastructure and reporting. Active buildings pose special concerns to stakeholders addressing cybersecurity in power, telecommunications, and building management. For instance, active buildings could start as new buildings, where all necessary controls are already in the design. However, older building managers and customers will observe the gains of changing towards active propositions. The retrofitting task of converting buildings into active buildings will present new challenges for protecting and securing customers participating the network.
## 2 Materials and Methods
### Metrics  
To determine whether the SVM algorithm was able to find the optimal solution for binary classification of the data, the numerical values that determine the quality of such a prediction were calculated.  
Firstly, we define the outcomes of the model classification compared to their real labels. The technique that helps to represent the quality of classification is the confusion matrix. In binary classification, this matrix consists of four values: true positives (TPs), false positives (FPs), false negatives (FNs), and true negatives (TNs) [26]. Every observation is placed in the proper cell according to the real and predicted value. Then, the confusion matrix is analyzed to define the quality of the classification.  
For binary classification, the three metrics extracted from the confusion matrix are used often when a dataset is unbalanced [27]. The first is precision:  
\[\text{Precision}=\text{TP}/(\text{TP}+\text{FP}). \tag{1}\]  
Precision indicates how well the algorithm classifies a positive class out of a provided dataset.  
The second metric is recalled, which indicates the ability of the model to capture positive cases:  
\[\text{Recall}=\text{TP}/(\text{TP}+\text{FN}). \tag{2}\]  
Since the goal of the experiment was to maximize both metrics, the third, auxiliary metric is usually introduced, the F-score:  
\[\text{F-score}=2(\text{Precision}\cdot\text{Recall})/(\text{Precision}+ \text{Recall}). \tag{3}\]  
The F-score represents the harmonic mean of the above two metrics. Therefore, maximizing this metric will improve the overall quality of the classification and in the case where harmonic mean smaller values have a strong impact on the result. In our case, this was especially important because the dataset was unbalanced. Thus, using a simple accuracy metric would not be sufficient. A model that classifies everything as one class may obtain a high score depending on the level of unbalance of the set. In addition, the previously mentioned metrics can be used to maximize individual classification tasks. For example, maximizing precision will allow for a much better classification of positive cases, i.e., eggs from sick hens. Unfortunately, this action incurs a tradeoff, i.e., observations belonging to the negative class are more likely to be incorrectly classified. This phenomenon is called the precision-recall tradeoff.
###### Abstract  
The IQ motif-containing GTPase-activating protein (IQGAP) family composes of three highly-related and evolutionarily conserved paralogs (IQGAP1, IQGAP2 and IQGAP3), which fine tune as scaffolding proteins numerous fundamental cellular processes. IQGAP1 is described as an effector of CDC42, although its effector function yet re-amins unclear. Biophysical, biochemical and molecular dynamic simulation studies have proposed that IQGAP RASGAP-related domains (GRDs) bind to the switch regions and the insert helix of CDC42 in a GTP-dependent manner. Our kinetic and equilibrium studies have shown that IQGAP1 GRD binds, in contrast to its C-terminal 794 amino acids (called C794), CDC42 in a nucleotide-independent manner indicating a binding outside the switch regions. To resolve this discrepancy and move beyond the one-sided view of GRD, we carried out affinity measurements and a systematic mutational analysis of the interfacing residues between GRD and CDC42 based on the crystal structure of the IQGAP2 GRD-CDC42Q61L GTP complex. We determined a 100-fold lower affinity of the GRD1 of IQGAP1 and of GRD2 of IQGAP2 for CDC42 mGppNHp in comparison to C794/C795 proteins. Moreover, partial and major mutation of CDC42 switch regions substantially affected C794/C795 binding but only a little GRD1 and remarkably not at all the GRD2 binding. However, we clearly showed that GRD2 contributes to the overall affinity of C795 by using a 11 amino acid mutated GRD variant. Furthermore, the GRD1 binding to the CDC42 was abolished using specific point mutations within the insert helix of CDC42 clearly supporting the notion that CDC42 binding site(s) of IQGAP GRD lies outside the switch regions among others in the insert helix. Collectively, this study provides further evidence for a mechanistic framework model that is based on a multi-step binding process, in which IQGAP GRD might act as a'scaffolding domain' by binding CDC42 irrespective of its nucleotide-bound forms, followed by other IQGAP domains downstream of GRD that act as an effector domain and is in charge for a GTP-dependent interaction with CDC42.  
Keywords:CDC42; GAP; GAP-related domain; GRD; GTPase activating protein; IQGAP; nucleotide-independent binding; RASGAP; RHO GTPases; scaffold protein; scaffolding protein; switch regions +
Footnote †: journal: Molecular Sciences
## 1 Introduction
Moreover, the underlying physical mechanisms of the latent variables remain unclear, and achieving accuracy and success in design remains challenging throughout the entire process, from matrix encoding to decoding and electromagnetic response prediction networks [23; 24]. A fundamental limitation of these deep learning (DL)-based methods is their pixel-like representation of metasurface structures, which restricts the generation of novel geometric structures. The resulting isolated pixel points also create significant challenges in terms of manufacturability. In this paper, we propose a new method for designing metasurface unit cells. Instead of relying on pixel-based representations, we model unit cells using ten continuous parameters for a greater variety of shapes and more flexible phase control. Additionally, by ensuring the rotational symmetry of the cells, we achieve polarization insensitivity. The continuous variable form is also more advantageous for optimization algorithms compared to discrete matrices. By combining the simulated annealing algorithm to optimize the parameters, a chessboard metasurface is constructed, achieving a wideband 10 dB RCS reduction from 7.6 to 15.5 GHz. This method provides a new paradigm for designing novel foundational structures in metasurfaces, enabling greater design flexibility and performance. Section 2 details the design theory and methodology, including the parameterized rotational symmetry strategy and the SA optimization framework. Section 3 presents the numerical and experimental results, validating the broadband RCS reduction performance and angular stability of the proposed metasurface. Section 4 concludes the work.
# Shear Strength of Trapezoidal Corrugated Steel Webs for Horizontally Curved Girder Bridges
## 5 Conclusions  
In this paper, the shear capacity of CSWs for HCGs is theoretically, numerically and experimentally studied, and the following main conclusions can be drawn:  
1. The CSW in HCGs is treated as an orthotropic cylindrical shallow shell, and the analytical formula for the elastic global shear buckling stress is deduced by the Galerkin method. Simplified formulas for the global shear buckling coefficient \(k_{g}\) for a four-edge simple support, for a four-edge fixed support, and for the two edges constrained by flanges fixed and the other two edges simply supported are proposed.
2. A parametric study based on a linear buckling analysis is performed to analyze the effect of the curvature radius and girder span on the shear buckling stress. Analytical and numerical results show that the difference of shear buckling stress of CSWs between curved girders and straight girders is small, so the shear design formulas for straight girders can be applied for curved girders.
3. Loading tests were performed on three curved box girders with CSWs. Similar to CSWs in straight girders, the shear strain distributions of CSWs in HCGs are almost uniform along the direction of the web height and the principal strain direction angles are close to 45\({}^{\circ}\). For the three specimens, CSWs carry about 76% of the shear force. In the destructive test, shear buckling after yielding occurred in all specimens which is in good agreement with the theoretical prediction,  
Figure 17: Load-deflection curves of test girders at mid-span section: (**a**) S1-t1d2; (**b**) S2-t2d2; (**c**) S3-t2d3.  
which means that the analytical formulas provide good predictions for the shear buckling stress of CSWs in HCGs and can be applied for design purposes.  
[PERSON] did the derivation of the global shear buckling stress of CSWs for HCGs and performed the finite element analysis and writing. [PERSON] and [PERSON] designed and performed the experiment. [PERSON], L.T. and [PERSON] did the review and editing.  
This research was funded by the National Natural Science Foundation of China, grant number 51378106 and the China Scholarship Council. The financial support is gratefully acknowledged.  
The authors declare no conflict of interest.