esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Identification of Boundary Conditions
### Seawater Conditions  
The second parameter needed for the analysis was the temperature of the seawater at the surface and at a short depth (i.e., less than 5 m). Indeed, the refrigeration systems installed on-board exploit such a medium for waste heat rejection and therefore it is a crucial parameter in the definition of the performance of the refrigeration system, for the traditional one and the sorption one.  
Data from Moderate Resolution Imaging Spectroradiometer (MODIS) sea surface temperature, 8 km Infrared (IR) measurement, from a dataset from 2000 to 2014 [30] were used: the average monthly surface temperature of four areas was obtained, the Mediterranean Sea, the North Sea, the North African coast of the Atlantic Ocean, and the South East coast of the Indian Ocean. The data collected are reported in Figure 2, where it is possible to notice the wide variability of the temperature in the Mediterranean and North Sea, with a maximum difference between summer and winter of about 10 K for the former and almost 18 K for the latter. On the contrary, the temperature profile of the oceans is almost flat, with temperatures in the range 25-28 \({}^{\circ}\)C for the entire year. Starting from these values, for simplicity reasons, the dataset was reduced to the design conditions for the refrigeration system reported in Table 2.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Case** & **A** & **B** & **C** & **D** \\ \hline \(La\times B\times Dm\) & \(15\times 4.5\times 1.6\) & \(18\times 6.0\times 2.0\) & \(20\times 6.9\times 2.5\) & - \\ Fish hold capacity (m\({}^{3}\)) & 20 & 40 & 60 & 10 \\ Engine power (kW) & 250 & 425 & 500 & 190 \\ Fish stowing rate (kg/m\({}^{3}\)) & & & 500 & \\ Fish amount max (t) & 10 & 20 & 30 & 5 \\ Days of operation & 20 & 20 & 25 & 10 \\ Fish caught daily (kg/d) & 500 & 1000 & 1200 & 500 \\ Displacement & 400 & 800 & 1000 & 300 \\ Incidence of refrigeration on engine consumption & 6\% & 7\% & 9\% & 7\% \\ \hline \hline \end{tabular}
\end{table}
Table 1: Main features of the fishing vessels considered.  
Figure 2: Temperature of seawater temperature in the chosen locations.
## 2 Beam-to-Column Connections
### BCC-2: Curved-Slotted Hole System  
The second device analyzed is endowed with curved slotted holes and achieves the upper connection to the column by means of a T-stub, which is expected to develop a plastic hinge in correspondence to its weakest cross-section characterized by two 20 mm diameter holes (Figure 2a). This solution has five M18 preloaded bolts of class 10.9; the internal lever arm is \(z_{2}=380\) mm, and the angle \(\alpha_{2}=68^{\circ}\). The FE types used in this model are first-order tetrahedra (C3D4) for the steel elements of the connection, with the exception of the C-profile used for connecting the upper T-stub to the column. This C-profile is modeled with linear hexahedra (C3D8R), as well as the concrete column. Moreover, two-node linear beam elements are used for modelling the HSTCB reinforcement (longitudinal and diagonal rebars, and vertical and inclined stirrups). The FE model developed is more detailed because it takes into account the nonlinear behavior of the materials [17]. The main  
Figure 1: Solution BCC-1: (**a**) detail of the system; (**b**) cyclic response; and (**c**) stress state at peak.  
mechanical parameters of concrete are: f\({}_{\text{c}}\) = 25 MPa (compressive strength), E\({}_{0}\) = 28,960 MPa (elastic modulus), f\({}_{\text{t}}\) = 2.56 MPa (tensile strength), and G\({}_{\text{F}}\) = 0.13 N/mm (fracture energy). The modelled steel is class B450C for rebars embedded in concrete and S355 for plates, with elastic modulus E\({}_{\text{s}}\) = 210,000 MPa. The constitutive model of steel considers an elastic perfectly plastic behavior. Moreover, the FE model considers a perfect bond between the concrete core and the steel truss and reinforcement of the beam. The other main contact properties are assumed as follows: frictionless sliding between the bottom plate of the beam and the concrete core; frictional behaviour between the sliding steel plates, with a friction coefficient equal to 0.4; and ideal rigid contacts in all normal local directions. The results of a cyclic analysis with imposed displacement of \(\pm\)100 mm are reported in Figure 2b; it can be noted that this device does not present the negative sliding effect previously due to the clearance in the top hinge; here, the center of rotation develops near the weakest cross-section of the T-stub (Figure 1c), allowing a major dissipation capacity, even though a slight shifting of the rotation center is noticed during the analysis. The responses for the positive and negative bending moments are almost symmetric, and limited damage is experienced during the loading-unloading cycles.
# Additive Manufacturing of Variable Density Lenses for Radio Frequency Communications in X-Band
## 3 Horn Antenna and Gradient Index Lens Design
### Mechanical Design  
The feeding horn antenna and the lens were assembled using a mechanical support. The support was required to provide structural resistance without affecting electromagnetic performance of the antenna, promote the modularity of the system, as well as allow for the exchange of the three types of lenses. The dimensions of the support are outlined in Figure 8c and their values are given in Table 3. A four-piece design was chosen, with the pieces connected by pegs, allowing for easy assembly and disassembly. Additionally, to reduce the weight of the support while maintaining its structural resistance, it was designed as a series of rods connected by St. Andrew's crosses, as shown in Figure 10. The mechanical support was designed using Solidworks v.2025 software.
## 3 Case Study
### Calculation of Diesel Engine without Shock Absorbers in Impact Condition
#### 3.4.2 Crankshaft Stress of Diesel Engine without Shock Absorbers in Impact Condition  
As shown in Figure 21, the crankshaft stress at the first crank pin at 0.359048 s has reached 865 MPa, which has exceeded the yield limit of the crankshaft material (650 MPa). Therefore, the diesel engine without the shock absorbers will not work normally due to irreversible plastic crankshaft deformation under external impact.  
Combining the calculation results of the main bearing lubrication and the crankshaft stress, the diesel engine without shock absorbers will not work normally under the external impact.  
This calculation result is consistent with the facts observed by [PERSON] [62] in a underwater explosion experiment of a real ship: \"The test results show that under the same test environment, rigidly mounted diesel engines (without the shock absorber) are more likely to be damaged than elastically mounted diesel engines (with the shock absorber). Most of the impact energy was absorbed by shock protection device\".  
Therefore, in order to improve the survivability of naval diesel engines on the battlefield, it is strongly recommended to install shock absorbers or other anti-shock protection devices.
## 5 Discussion
However, the models with all configurations added consistently resulted in higher performance. This improvement was particularly striking for the ResNet 34 encoder, which showed an increase in the DSC from 0.9541 (ResNet34 only) to 0.9612 (ResNet34 with self-attention layer, blurring and bottleneck). However, adding to the complexity of the model comes with an increased computational cost, especially when adding the self-attention layer. For example, the inference time for the entire DCE image sequence is 114.2 s for ResNet34 only, but this increases by 6.3 s when adding the self-attention layer, while adding the bottleneck connection causes an increase of only 2.1 s (Table 5). The best performing model before post-processing is the ResNet34 featuring all proposed additions. The considerable improvement in segmentation accuracy over a standard ResNet encoder may justify the additional computational cost. ResNet50 configurations performed worse than the smaller ResNet34 architectures. This is likely due to underfitting, and having access to more data would be extremely beneficial and most likely would lead to better performance than ResNet34 on larger training datasets. The difference between the worst performing architecture (ResNet18 with bottleneck connection) and the best performing architecture (ResNet34 with all proposed additions) can be seen in Figure 7 below. In cases of limited computational resources, both at training time and at inference time, the ResNet18 configurations would be the recommendation. Figure 7: Comparison of results. The input images to the algorithms (**a**); the results from the worst performing algorithm (ResNet18 with bottleneck connection) (**b**); the results from the best performing architecture (**c**). The generated masks are purple, while the yellow coloring represents the areas of disagreement with the manual labeling. Abbreviations: BC—bottleneck connection, BL—blurring mechanism, SA—self-attention layer. As the refinement algorithm is applied, improvements can be uniformly observed across all model configurations. By removing the bottom boundaries of the generated masks, the mean JSC is increased by 0.098, and the average DSC is increased by 0.026. The low variance of both similarity coefficients corroborates the observation that aggressive data augmentation is one of the main causes of irregularities in the generated masks (Table 4).
# Two Scenario-Based Heuristics for Stochastic Shift Design Problem with Task-Based Demand
## 3 Solution Approach
### Two-Stage Heuristic
#### 3.4.2 The Second Phase of TSH  
Use \(H^{d}\) to denote the d-th shift plan in the set \(H^{D}\). Since in the set \(H^{D}\) derived in the first stage, the later the shift plan is designed, the more scenarios can be covered, i.e., the coverage of each shift plan in \(H^{D}\) increases as d increases. Therefore, we can use the bisection method to search for a shift plan from \(H^{D}\) that both satisfy the probability constraint (A9) and perform well in terms of cost.  
The specific algorithm is as follows:  
1. Initialize the parameters \(\mathrm{s}=1\), \(\mathrm{t}=\big{|}H^{\mathrm{D}}\big{|}\), \(\mathrm{d}=\mathrm{t},\mathrm{q}=0,q^{*}=0,H^{*}=\varnothing,C^{*}=0\). Use \(H^{d}\) to denote the \(\mathrm{d}\)-th shift plan in the shift plan set \(H^{D}\) and go to step 2.
2. Generate \(\mathrm{M}\) scenarios by perturbing the start time of tasks in task set \(\mathrm{K}\). Take \(H^{d}\) and each of these \(\mathrm{M}\) scenarios as the input of TAA, respectively, and denote the number of occurrences \(K^{u}=\varnothing\) by \(\mathrm{Q}\). Let \(\mathrm{q}=\mathrm{Q}/\mathrm{M}_{d}q^{*}=q\),\(H^{*}=H^{d}\), and calculate the inherent cost \(c^{H^{d}}\) and the expected cost \(C^{*}\) of the shift plan \(H^{d}\), where \(c^{H^{d}}=\alpha\sum_{h_{t}^{d}\in H^{d}}w_{h_{t}^{d}}\Big{(}e_{h_{t}^{d}}-s_{h _{t}^{d}}\Big{)}\), \(C^{*}=c^{H^{d}}+\mathrm{E}(\delta_{H^{d}})\). If \(\mathrm{q}\geq\eta\), then go to Step 3; otherwise go to Step 6.
3. Let \(\mathrm{d}=(s+t)/2\). If \(\mathrm{t}-\mathrm{d}\leq 0\), then go to Step 6, otherwise go to Step 4
4. Generate \(\mathrm{M}\) scenarios by perturbing the start time of tasks in task set \(\mathrm{K}\). Take \(H^{d}\) and each of these \(\mathrm{M}\) scenarios as the input of TAA, respectively, denote the number of occurrences \(K^{u}=\varnothing\) by \(\mathrm{Q}\), and let \(\mathrm{q}=\mathrm{Q}/\mathrm{M}\). If \(\mathrm{q}\geq\eta\), then go to Step 5; otherwise, let \(\mathrm{s}=\mathrm{d}\) and go to Step 3.
5. If \(C^{*}\geq c^{H^{d}}+\mathrm{E}(\delta_{H^{d}})\), then let \(H^{*}=H^{d},C^{*}=c^{H^{d}}+\mathrm{E}(\delta_{H^{d}})\), \(q^{*}=q\), \(\mathrm{t}=\mathrm{d}\) and go to Step 3; otherwise, let \(\mathrm{t}=\mathrm{d}\) and go to Step 3.
6. Output \(H^{*},C^{*}\) and \(q^{*}\).  
\(H^{*}\) is a shift plan that satisfies the probability constraint (A9) while performs well in terms of the expected cost (the expected cost of this plan is \(C^{*}\)), and the probability that this shift plan can provide a sufficient workforce for all tasks in \(\mathrm{K}\) on the operation day via TAA is \(q^{*}\).
# Revolutionizing Urban Pest Management with Sensor Fusion and Precision Fumigation Robotics
## 3 Mapping and Hotspot Identification  
### Autonomous Exploration of the Robot  
The fumigation robot developed aims to find mosquito hotspots. In the proposed approach, the robot explores the environment, identifies the hotspots, and saves the position of those hotspots. Before identifying hotspots, a map of the environment is needed for the robot to navigate through it. The proposed system opted for an occupancy grid-based 2D map. Different occupancy grid mapping techniques exist, such as hector slams, gmapping, and cartography. The map produced consists of cells. Each cell has cost values associated with it, signifying the presence and absence of the object. If the object is present, then a high-cost value is given to the cell. Usually, black spots are considered obstacles, and grey areas are considered accessible areas, as shown in Figure 4. The occupancy grid map was made using a SICK TIM351 LiDAR. The ROS package used for this was gmapping. This package takes in laser-scan data from the sick_tim package and converts the data into an occupancy grid map. The map of the environment generated from the 2D and 3D LiDARs is illustrated in Figure 4.  
Figure 3: YOLOv8 architecture for detecting hotspots.
## 2 Methodology  
### Geopolymer Composite Preparation  
A metakaolin-based (MK) potassium geopolymer matrix (KGP) was prepared by the addition of MetaMAX \(\copyright\) from BASF and potassium metasilicate solution, also known as waterglass (KWG). MetaMAX \(\copyright\) is an aluminosilicate kaolin clay that has been heated to approximately 750 \({}^{\circ}\)C and has an average particle size of 1.3 \(\upmu\)m [39; 40]. A potassium metasilicate solution was synthesized by dissolving 85% assay potassium hydroxide flake and fumed silica, from ChemSupply Australia, into deionized water. The mixture was stirred at 300 rpm for 24 h using a magnetic stir bar, ensuring the total dissolution of the fumed silica. Metakaolin clay was then high-sheared into the KWG solution for 5 min at 2000 rpm using an IKA\(\copyright\) RW 20 high-shear mixer and dissolver attachment to produce a homogenous KGP slurry. The KGP slurry was de-aerated for 5 min using a vibration table. Equation (1) and Equation (2) show the formation of KWG and KGP.  
\[2\text{KOH}+2\text{SiO}_{2}+10\text{H}_{2}\text{O}\ \rightarrow\text{K}_{2} \text{O}\bullet 2\text{SiO}_{2}\bullet 1\text{H}_{2}\text{O} \tag{1}\]  
Equation (1): Formation of potassium metasilicate solution from SiO\({}_{2}\), deionized water, and KOH  
\[[\text{K}_{2}\text{O}+2\text{SiO}_{2}+11\text{H}_{2}\text{O}]+[\text{Al}_{2} \text{O}_{3}\bullet 2\text{SiO}_{2}]\rightarrow[\text{K}_{2}\text{O} \bullet\text{Al}_{2}\text{O}_{3}\bullet 4\text{SiO}_{2}\bullet 1\text{H}_{2}\text{O}] \tag{2}\]  
Equation (2): Formation of potassium geopolymer from metakaolin clay and potassium metasilicate solution  
Fifty-micron alumina platelets from Micro Abrasives were then added to the KGP slurry and high-sheared for 5 min followed by 2 min on a vibration table to remove entrapped air. System 96\(\copyright\) glass frit powder of particle size 10-250 \(\upmu\)m from Oceanside Glass and Tile was then added to the mixture, high-sheared for 5 min, and de-aerated for another 5 min. The homogenous mixtures were then poured into plastic molds and placed in a 100% relative humidity curing chamber for five days. Plastic molds were made from modified PVC plumbing pipe and caps, as well as PVC rod. Weight percents, both reference and measured densities, and calculated volume percents of each phase are presented in Table 1. The elemental composition of glass frit powder was measured using EDS and is presented in Table 2. The glass frit powder is most similar to sodalime glass with the minor addition of impurities, which are used to prevent crystallization upon melting and cooling among other properties [41].
## 1 Introduction
For instance, the THz-ARTE project between Italian teams, the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) in Frascati and the \"Nello Carrara\" Institute of Applied Physics of the National Research Council (IFAC-CNR) in Florence, and the Japanese teams, Institute for Information and Communications Technology (NICT) in Tokyo and the Nara National Institute for Cultural Properties (NNRICP) in Nara, was focused on extending the imaging techniques mentioned above to the use of CW sources in the 20 GHz-0.3 THz range and to develop new ones, in order to provide additional information on the optical properties, not only of the sample surface, but also of the underlying materials, thus supplying information regarding the internal structure of the samples.
# Review of GaN Thin Film and Nanorod Growth Using Magnetron Sputter Epitaxy
## 3 MSE Growth of GaN Thin Films Using Liquid Ga Target
### Pulsed DC Sputtering and High-Power Impulse Magnetron Sputtering (HiPIMS)  
Pulsed DC sputtering, also known as pulsed sputter deposition (PSD), is a technique where the sputtering target is biased with a pulsed DC voltage, usually in the range of hundreds of volts [54]. During the pulse on period, the target is biased with negative voltage, initiating the sputtering process by the ions. During the off period, the target is typically biased with low positive voltage in order to clear up any charge buildup. Pulsed sputtering enables the supply of high-energy precursors onto large-area substrates, enabling low-temperature growth and significant reduction in threading dislocations. DC pulsed sputtering has been used extensively for the growth of III-nitrides [11; 12; 13; 14; 37; 55; 56; 57; 58; 59; 60; 61; 62; 63; 64] resulting in various III-nitride based devices, which is discussed in Section 3.4.  
HiPIMS is a pulsed sputtering method characterized by very high peak power (\(>\)10 MW) in short pulse on period in the range of 50 to 200 \(\upmu\)s. Research in HiPIMS gained traction after the publication of the seminal paper by [PERSON] in 1999 [65]. HiPIMS has the advantage of producing film with better adhesion, high density, low roughness, and no droplet formation. The high-density plasma produced in HiPIMS results in the ionization of the sputtered metal atom, up to 90% depending on the metal and applied power per pulse. Using metal ions is more advantageous compared to using inert gas ions for enhancing adatom mobility. Inert gas ions can reside at the interstitial sites of the film, resulting in residual compressive stress, whereas in the case of metal ions, the metal is incorporated into the lattice of the growing film [66].  
The growth of GaN using a HiPIMS system was first demonstrated by [PERSON] et al. [10], who grew a GaN(0001) film directly on \(c\)-plane sapphire. The growth was performed using a liquid Ga target under a mixture of N\({}_{2}\)/Ar gas. TEM results show that the thin film is composed of two domains with different strains, referred to as the less strained (A) and more strained (B) domains, shown in Figure 5. The less strained domain is almost fully relaxed, with superior structural and optical properties, with a rocking curve FWHM of 885 arcsec and low temperature band edge luminescence at 3.37 eV with an FWHM of 10 meV. On the other hand, the more strained domain has \(\sim\)14 times higher isotropic strain components, caused by the higher number of point defects density caused by ion bombardment during growth. The more strained domain shows a band edge luminescence at 3.48 eV with a broader FWHM of \(\sim\)14 meV due to the lower material quality. Based on these results, a good control of stable HiPIMS growth condition is necessary in order to produce high-quality GaN film. For example, a substrate bias can be used to slow down the incoming ions, or by adjusting timing of the bias pulse to filter out which ions are allowed to reach the substrate.
# A Survey of Vehicular VLC Methodologies
## 6 Vehicular VLC Channel Modeling and Propagation Characteristics
### Key Parameters of Vehicular VLC
Moreover, to solve the mobility issue, one must first thoroughly comprehend the many motions the vehicular VLC system could experience, both in magnitude and type. The movement of vehicles is characterized by a model representing the relative placement along all three spatial dimensions of two cars (the transmitter and the receiver). The following identifies the motion model as a vector [34; 37; 38]:  
\[M=\left[\delta u\;\delta v\;\delta w\;n\right] \tag{5}\]  
where \(\delta u\) represents the relative movement along the horizontal axis (\(X\)), \(\delta\)v represents the relative movement along the vertical axis (\(Y\)), \(\delta\)w denotes the relative motion within the length of the driving path (\(Z\)), and n indicates the value of the flag, which represents the type of vehicle behavior class. This section describes the motion model for specific time slots. The values of relative movement illustrate the movement that occurred during a specific period. The vehicle action category describes the type of movement experienced by the vehicle during that particular time window. In addition, the influences and ability of the V2V VLC approach must be considered within the several output applications, which leads to a significant deterioration in the completion of the communication link. The transformation needs to consider the fact that there is a substantial increase in environmental noise. There must be a lateral separation of the vehicle and a longitudinal separation between the two connected cars, which must be considered since there are parked or moving vehicles near the two connected cars. Moreover, since the LED for the VLC is mainly used with low-range communications, the longitudinal separation method significantly impacts the connection of the two vehicles to each other, affecting the system's ability to work effectively [37; 38; 124].
## 5 Discussion
### Limitations and Future Prospects of the Study
In the future, with further exploration of the relationship between SIF and GPP, as well as optimization of the remote sensing ecosystem respiration model, this method is expected to become one of the effective means for estimating forest carbon sinks in areas lacking flux observation data. To address the issues discussed in this paper, future studies could utilize alternative remote sensing products for estimation, selecting the most accurate ones; incorporate new factors such as radiation intensity, temperature, evaporative components, and soil moisture to refine calculations; and explore the applicability of the method with respect to different time periods and tree species. Continuous improvements in research topics and methodologies can enhance the feasibility, applicability, and accuracy of using SIF remote sensing to estimate forest carbon sinks, leading to a deeper understanding of global carbon cycles and climate change.