esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Genetic Algorithm Optimization  
With the HMS synthesis method presented in the previous section, it is possible to fix the position of one or more main lobes. However, to achieve more precise control over both the intensity of these lobes and the position of the nulls, optimization techniques are implemented. These techniques allow for fine-tuning of the radiation pattern, ensuring that both the desired beam directions and null locations are accurately achieved, improving the overall performance of the antenna. The objective of this optimization is to configure the radiation pattern as closely as possible to the desired outcome. To achieve an optimal configuration, nulls are imposed at specific angles in the radiation pattern while keeping the main beam position fixed. Constraints are applied to maintain the desired directivity in both the null and main beam directions. The key advantage of using a GA lies in its ability to efficiently search for integer solutions, which narrows the configuration space and accelerates convergence. Once the GA determines the required phase shifts for each metasurface element to achieve the desired radiation pattern, the corresponding surface reactances are calculated to match these phase values. This ensures that the metasurface is precisely designed to deliver the desired radiation characteristics.  
The workflow presented in the diagram of Figure 2 outlines the optimization process for synthesizing a circular HMS structure. It begins with the modeling of a circular antenna array in MATLAB (version R2024b), where the radiating elements are designed to emulate the behavior of a HMS with zero phase shift and a unitary transmission coefficient. The initial step involves the synthesis of the circular array exploiting Equation (1), which provides directivity values for the main lobe. These preliminary directivity values are then enhanced through the implementation of GA optimization. Specifically, it is necessary to define input data, including the initial HMS structure derived from a circular array synthesis and the desired main beam direction and null positions. The GA optimization is employed to iteratively adjust the directivity and null values, targeting convergence based on predefined criteria such as tolerance thresholds and maximum iterations. The switching criterion ensures that the optimization loop continues until these conditions are satisfied, i.e., the optimization targets a +20 dB directivity for the main lobe and a \(-\)20 dB for the nulls at the specified angle. Once convergence is achieved, the output consists of the calculated reactance values for each HMS cell, which are then used to finalize the metasurface design. This workflow provides a systematic approach to achieving precise null-steering and optimal radiation characteristics using metasurface technology.
## 4 Discussion  
### Overview  
The findings in this study provide new insight about the duration to which the area near Bimini, The Bahamas, is used across ontogeny for tiger sharks and their dispersal in the western North Atlantic Ocean. All age classes, from young-of-year (YOY) to sexually mature, were captured, including several females being confirmed near-term or recently post-partum. Residency within the immediate area surrounding Bimini was predominately driven by size and water temperature, with small juvenile tiger sharks rarely recaptured and only detected over short durations. However, small juveniles were also infrequently detected by cooperative acoustic arrays in the region, potentially indicting limited regional dispersal of this age class or high natural mortality. Larger juveniles and mature tiger sharks were monitored around Bimini over longer durations, with increased residency during the cool water winter months. Large juvenile and mature tiger sharks were also tracked more frequently throughout the broader western North Atlantic region. Some larger tiger sharks also returned to Bimini after prolonged absences, including annual returns of up to five years, providing evidence for multi-year fidelity to this area. Taken together, these findings show the area is important for tiger sharks, including as a pupping ground.  
Figure 7: Utilization distribution comprising all tiger sharks, _Galeocardo curier_, tagged with SPOT transmitters near Bimini, The Bahamas. The Bahamas Exclusive Economic Zone (’EEZ’) is denoted by the teal line.
## 1 Introduction  
For several decades, the ability to generate tunable or switched multi-wavelength fiber lasers has been one of the focuses pursued by the fiber laser community. These lasers are associated with many reliable applications related to multi-wavelength spectra such as optical fiber sensors [1; 2; 3; 4; 5; 6; 7; 8; 9], spectroscopy systems [10], biomedical imaging [11], telecommunications [12], microwave photonics [13], and radio frequency optical domain systems [14]. These applications require achieving compact configuration, stable emission, narrow linewidth, and adequate spacing mode. All these features prevent crosstalk, error measurement, and low resolution. To this end, many methods have been proposed, most of them based on fiber interferometers (Fabry-Perot, Mach-Zehnder, Michelson, and Sagnac) [15; 16; 17; 18; 19], comb filters [20; 21], Raman effect [20], Brillion scattering [22; 23], nonlinear loop mirrors [24], saturable optical absorber elements [25; 26], and extrinsic interferometers [27].  
These proposed schemes offer compactness, high power stability, minimal wavelength drift, and adequate signal-to-noise ratio, long operation time, and low threshold. Furthermore, some research groups have demonstrated the capability of tunable multi-wavelength [28; 29; 30; 31; 32; 33]. The most common techniques to overcome modal competition and achieve multi-wavelength spectra are Four-Wave Mixing (FWM) and Stimulated Brillouin Scattering (SBS). However, these techniques require several meters of highly nonlinear fiber optics, and polarization plays an important role; this entails complex configurations and costly implementation. Moreover, in some arrangements, the multi-wavelength tuning effect undergoes lasing power disparity, small side mode suppression ratio, and power dependence. One of the most common setups used to overcome the undesired effect is the recognized ring fiber laser cavity based on modal fiber interferometers [26; 27; 28; 29; 30; 31; 32; 33].  
In this work, a cost-effective modal interferometer and simple ring laser cavity are used to demonstrate the multi-wavelength effect. The laser arrangement was governed by a modal fiber structure operated in reflection mode; the structure was set into an erbium fiber ring laser cavity, resulting in a quad-wavelength laser. This initial laser spectrum had a wavelength drift of around 0.008 nm and power variations of 0.46 dB. The refractive index and thermal variations around the modal interferometers were assessed to provide a simple method for tuning multi-wavelength spectra. The spectrum was analyzed when refractive index changes were applied around the fiber filter; here, two dual-wavelength spectra were tuned with a resolution of 0.05 nm. Minimal power and wavelength variations were observed through the tuned range. To assess the thermal effect, a temperature exceeding 90 \({}^{\circ}\)C was applied over the fiber filter, tuning dual and triple wavelength spectra. Most of the spectra achieved had an adequate side mode suppression ratio, high peak level, lower wavelength drift, and minimal power variation.
## 5 Simulation and Analysis of Positioning Strategy of Constellation Station
### Simulation Scheme and Result Analysis of Absolute Station-Holding Strategy
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Control Time/d**} & \
\begin{tabular}{c} **Interval from Last** \\ **Control Moment/d** \\ \end{tabular} &
\begin{tabular}{c} **Maximum Adjustment of** \\ **Semi-Major Axis/m** \\ \end{tabular} \\ \hline
1 & 13.22 & 13.14 & 59.12 \\
2 & 26.36 & 13.40 & 60.3 \\
3 & 39.76 & 13.24 & 59.58 \\
4 & 53.00 & 13.33 & 59.98 \\
5 & 66.33 & 13.21 & 59.44 \\
6 & 79.54 & 13.17 & 59.26 \\
7 & 92.71 & 13.53 & 60.88 \\ Average & / & 13.29 & 59.79 \\ Total & 92.71 & / & 418.56 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Orbital maneuver time interval and semi-major axis change. Figure 6: Phase–maintenance period and semi–major axis change of satellite 1. Figure 7: Phase–maintenance period and phase difference change of satellite 1.  
orbital maneuvering was within 5%. Therefore, the absolute station position autonomous phase-holding method could complete the satellite phase-holding task. This method can be extended to the absolute station position holding of the constellation phase, which has significant advantages in large\(-\)scale constellation station holding.
# Vision-Aided Localization and Mapping in Forested Environments Using Stereo Images
## 3 Localization and Mapping
### Local Refinement  
Given the globally aligned state vector \(\hat{\mathbf{s}}\), we will now optimize for a refined state vector by taking into account observations of tree stems. There are three main steps in local refinement: (1) We transform each tree stem observation to the world coordinate frame according to the globally aligned state vector we optimized in the previous section. (2) We associate the observations corresponding to an individual tree stem position in the global map. (3) We optimize for a new configuration of the state that minimizes both the error functions from the previous section and an additional error function representing the discrepancy between observations of tree stems and their associated global position.
# Infrared Dim and Small Target Detection Based on Local-Global Feature Fusion
## 1 Introduction
We are inspired by the convolutional block attention module (CBAM) ([PERSON] et al., 2018), which enhances target features in both spatial and channel dimensions. Specifically, we design a multi-scale module that integrates global and local features, establishing a fusion mechanism by leveraging dual information. The magnification of the focus area enhances target features, improves target saliency, and achieves accurate positioning by fusing with global feature information. In summary, the main contributions of this work are as follows:  
1. To address the challenge of limited feature information in infrared dim and small targets, we propose a novel module that zooms in on the focus area. This focus area is initially randomly determined and then dynamically updated to match the target area based on the output of the algorithmic model. By enhancing the detailed information in this area while maintaining the overall characteristics of the background, our approach improves detection performance for these challenging targets. 2. To tackle the low contrast between infrared dim and small targets and their background, this study optimizes the multi-scale fusion structure within a dual-path feature extraction network, which captures positional and semantic information at different stages, enabling precise detection.
# Adaptive Energy Management in 5G Network Slicing: Requirements, Architecture, and Strategies
## 5 Evaluation
### Numerical Results
#### 5.3.3 Results and Discussion  
The simulation results in Figure 8 confirm the effectiveness of OptTsNS to improve power consumption, as reported in values of metrics \(AR\), \(E_{A_{U}}\), and \(P_{LACK}\) in Figure 8a-c, respectively. As the time shifting value increases (from 0 to 4) and as the quality degradation level decrease (from 1 to 0.5), OptTsNS has the ability to distribute the services in time and minimize the power consumption, which consequently leads to efficient use all \(P_{A}\). In this regard, the algorithmic strategy enables reducing the peak loads (i.e., the peaks of power consumption) and obtain a flat consumption profile, which can be better adapted to energy generation. Thus, the use of management strategies enables the processing of services that, in normal conditions (i.e., without a management mechanism) would be inevitably rejected. For instance, in Figure 7, only services \(S_{3,1}^{2}\) and \(S_{5,1}^{3}\) could be processed, which corresponds to an \(AR=25\%\), in this case the most of the energy produced could not be used and would be wasted. In addition, the simulation of OptTsNS shows that, when this algorithmic solution is deployed at  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Parameter** & \(L\) & \(M\) & \(N\) & \(W\) & \(t_{k,j}^{i}\) & \(d_{k,j}^{i}\) & \(max\{u_{k,j}^{i}\}\) & \(p_{k,j}^{i}\) & \(Q\) & \(q_{k,j}^{i}\) \\ \hline
**Value** & 4 & 4 & 8 & 10 & 4 \(\forall k\) & 2 \(\forall k\) & 4, see Figure 7 & [1–4], see Figure 7 & 3 & [1, 0.75, 0.5], see Figure 7 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Parameters of OptTsNS and values regarding the case study.  
Figure 7: Energy provisioning and consumption profiles of the case study, and optimal energy allocation obtained with OptTsNS. **Parameters**: According to Table 6.  
the mobile network MANO entities, as shown in Figure 2, it can offer efficient and adaptive energy management for 5G systems, considering the context of network slicing and with the ability to manage and exploit renewable energy generation.  
For the analyzed use case, the improvements obtained with the algorithmic strategy are given in terms of energy utilization (as shown in Figure 8b), increased service processing (from \(AR=25\%\) until reaching an \(AR=100\%\), as shown in Figure 8a), and in reducing the use of energy from non-renewable sources to meet the complete energy demand (Figure 8c). The latter is of utmost importance in modern energy management systems that aim to achieve a reduction in OPEX and with minimal environmental impact.
# Research on Seismic Wave Quality Factor of Marble Jointed Rock Mass under SHPB Impact
###### Abstract  
In order to quantitatively describe the energy dissipation law of jointed rock mass, we obtained the jointed cores in laboratory conditions using marble from the roof and floor of Jinchanghe Lead-zinc mine in Baoshan. The dissipative degree of stress wave in marble jointed rock mass is measured by introducing quality factor \(Qs\) parameter. Based on the experimental principle of Split Hopkinson Pressure rod loading device (SHPB), we proposed a three-wave energy method of incident wave, reflected wave and projected wave for calculating jointed rock samples' quality factor \(Qs\) based on stress wave energy. Using the SHPB test system for multiple specimens taken from the same piece of rock mass shock compression experiment, the three groups of specimens under different loading conditions gained incident wave and reflected wave and transmission wave experimental data, using the method of stress wave energy to deal with stress wave data, and calculate the joint sample maximum storage energy, dissipation energy and \(Qs\) quality factors. The results show that: 1 The non-destructive breaking time-history strain of Dali rock mass under impact load is obtained by SHPB dynamic test system; combined with the deformation energy and dissipation energy calculation principle of quality factor, six groups of \(Qs\) experimental values are obtained. Although the \(Qs\) experimental values are discrete, the overall deviation is small with an average of 43.07. 2 AUTODYN-Code was used to simulate the damage and fracture characteristics of rock mass with different quality factors under explosive dynamic load. The results showed that the radius of rock mass compression shear damage area gradually increased with the increase in porosity, but it was not obvious.  
energy dissipation; quality factor \(Q_{i}\); SHPB impact test; numerical simulation 2022
# Integrated Optical Phased Arrays for Beam Forming and Steering
## 6 Wavelengths  
In terms of steering wavelengths, OPAs can be sorted into visible-spectral-range OPAs [41; 65], NIR OPAs [10; 12; 62; 93], and MIR OPAs [72; 102]. As summarized in Tables 1 and 2, the majority of the OPAs work at a center wavelength of 1.55 um.  
OPAs in the visible spectral range (from 400 to 700 nm) are required for a wide range of emerging applications, such as augmented and virtual reality displays, biological sensors, and imaging [55; 56]. Si\({}_{3}\)N\({}_{4}\) is transparent in the visible spectral range [65; 119]. The first large-aperture visible (635 nm) OPA with a sharp beamwidth of 0.064\({}^{\circ}\)\(\times\) 0.074\({}^{\circ}\) was demonstrated based on Si\({}_{3}\)N\({}_{4}\) WGAs. The aperture size was 0.5 \(\times\) 0.5 mm\({}^{2}\)[65]. The first chip-scale blue light (488 nm) OPA using a Si\({}_{3}\)N\({}_{4}\) platform achieved an FOV of 50\({}^{\circ}\) and a beamwidth of 0.17\({}^{\circ}\)[41].  
Demonstrated OPAs are mainly working in the NIR communication spectral range [6; 7; 8; 9; 10; 11; 12; 15; 16; 17; 13; 45; 46; 45] due to the transparency windows, high refractive index contrast of materials, convenient availability of sources, and CMOS compatibility. A Si\({}_{3}\)N\({}_{4}\) OPA achieved 2D beam steering with an FOV of 3\({}^{\circ}\)\(\times\) 17.6\({}^{\circ}\) at a fixed wavelength of 905 nm [62]. Another 16-channel Si\({}_{3}\)N\({}_{4}\) OPA showed an FOV of \(\sim\)12\({}^{\circ}\) and a beamwidth of \(\sim\)1.1\({}^{\circ}\) at 1.064 um [93].  
Additionally, MIR OPAs are attractive to chemical and biological sensing, spectroscopy, thermal LiDAR, and free-space optical communications overcoming some atmospheric turbulence and scintillation [72; 124]. OPAs based on Ge/Si\({}_{3}\)N\({}_{4}\) WGAs achieved 2D beam forming and steering at 4.6 um [72; 102]. A fabricated OPA was capable of 2D beam steering with an FOV of 12.7\({}^{\circ}\)\(\times\) 12\({}^{\circ}\) and a beamwidth of 3.08\({}^{\circ}\)\(\times\) 0.18\({}^{\circ}\)[72]. Another MIR OPA achieved the same FOV and a different beamwidth of 2.86\({}^{\circ}\)\(\times\) 0.47\({}^{\circ}\)[102].
## 3 Experimental Study
### Experimental Setup
#### 3.1.5 Change-Point-Detection-Based Target Label Construction  
Several labeling methods were used for the target RUL labeling because there was no given information in the dataset for RUL labeling. One of the most used models for target RUL labeling is the PwL degradation model proposed by [17]. In PwL-based RUL labeling, target RUL is considered constant due to normal operating conditions for the initial period and linearly decreases after the system begins to degrade. Generally, most studies use around 120-130 cycles as the maximum RUL for any cycle of the constant part of the PwL function [12; 17; 28]. Although a single constant maximum RUL value for all engines seems convenient for generalization, each engine has a different life-cycle length and degradation process. We used the Python library pwl to fit continuous PwL functions to one-dimensional time series data for change point detection [55].  
To find the earliest change point in the sensor data of each engine, we increased the desired number of line segments until there was no meaningful difference for the subsequent segmentation.  
Figure 9 shows this process for a randomly selected engine. Blue lines represent extracted sensor signals, red lines represent fitted linear lines, and dashed yellow lines represent the first breakpoint. The last point of the first line segment gives the first change point of the sensor data. In Figure 9, the line segments are increased stepwise from two to five. It is obvious that when there are two segments, the detection of the first change point becomes late. The number of desired line segment parameters was set to \"5\" because there was no significant improvement in detecting the first change point. When this process was applied to all engines for two PwL segments, the target RUL labels of these engines are observable in Figure 10.  
Figure 8: Illustration of sliding time window.
# Direct Measurement of Aerosol Liquid Water Content: A Case Study in Summer in Nanjing, China
## 2 Sampling Site and Instrumentation  
The field campaign was conducted inside the campus of Nanjing University of Information Science and Technology (NUIST) (32\({}^{\circ}\)12\({}^{\prime}\)20.82\({}^{\prime\prime}\) N, 118\({}^{\circ}\)42\({}^{\prime}\)25.46\({}^{\prime\prime}\) E), located in Nanjing, Jiangsu Province, China (Figure 1). The measurement period was from 30 July 2023 to 1 September 2023 (34 days). Two identical aerosol monitors (Thermo Scientific(tm) (Waltham, MA, USA) Personal DataRAM(tm) pDR-1500) (a type of nephelometric monitor, referred to as PDR hereafter) and one Thermo Scientific(tm) (Waltham, MA, USA) Model 5030i SHARP (Synchronized Hybrid Ambient Real-time Particulate Monitor, referred to as 5030i hereafter) were used. The sampling site is located west of an expressway (Jiangbei Expressway) and an industrial area (including Nanjing Iron & Steel United Co., Ltd. (Nanjing, China), Yangtze Petrochemical Co., Ltd. (Nanjing, China), and a number of other chemical and petrochemical engineering companies as well as power plants). The site is also surrounded by a residential area, and it is representative of the typical suburban environment with intense anthropogenic emissions.  
The 5030i monitor combines the light-scattering nephelometry and beta attenuation technique and provides accurate, fast, and real-time PM\({}_{2.5}\) mass concentrations with low detection limits. It reports the dried PM\({}_{2.5}\) mass concentration, denoted as 5030i_PM. The two PDRs were placed parallel to one another and share a sampling line with a PM\({}_{2.5}\) cyclone placed about 10 m above the ground. The sample air was dried (typically to an RH under 20%) and fed into a PDR, which measured the PM\({}_{2.5}\) mass concentration, denoted as PDR_dry. We used a dryer filled with silica gel to remove the moisture from the air before entering into the PDR_dry. In order to keep the dryer operating effectively, we changed the silica gel at least every 2 days (sometimes more frequently according to the weather conditions). Another PDR was directly connected with the ambient air flow without the removal of moisture. Thus, the determined PM\({}_{2.5}\) mass concentration was denoted as PDR_wet_original, and this PDR also recorded the temperature and RH of the ambient air. For consistency, the time resolution was set to 1 min for both the PDRs and 5030i. Other instrumental details about the PDR can be found in previous works [34; 38; 39].  
The concentrations of common gaseous pollutants (NO\({}_{2}\), SO\({}_{2}\), O\({}_{3}\), CO) were acquired simultaneously using a series of Thermo Scientific monitors. Meteorological parameters such as the wind speed (WS) and wind direction (WD) were obtained from an automated weather station (Vaisala WXT520) located at the same sampling site. Visibility data were obtained from a nearby national environmental monitoring station. Note all the data reported here are shown in Beijing time (UTC + 8).