esa-sceva/satcom-chunk-collection huggingface dataset:
## 4 Discussion  
### Trends in the Spatial and Temporal Evolution of Vegetation GPP  
Precipitation changes across the Qinghai-Tibet Plateau display significant regional variation, with some areas exhibiting minimal or decreasing trends and most regions demonstrating an increasing precipitation trend. Precipitation changes in the northern and northwestern regions remain relatively minor, with slight decreases observed, potentially associated with regional climate characteristics, moisture sources, and other natural factors including prevailing wind patterns and topographic features, which are consistent with previous findings [46]. Overall, the annual mean temperature across most regions exhibits an increasing trend, potentially reflecting the long-term warming tendency of regional climate. Similarly, radiation levels in most regions have exhibited an increasing trend, suggesting that both local and large-scale factors have contributed to enhanced regional radiation during this period. This phenomenon likely reflects climate change impacts, including regional temperature rise and enhanced evaporation rates [47].  
Negative correlation areas account for 15.7% of the total, with limited regions demonstrating an inverse relationship between VPD changes and associated factors. This phenomenon may be attributed to increases in localized humidity or other regulatory mechanisms, leading to a decline in VPD in these specific areas. This trend likely indicates an intensification of water evaporation processes associated with temperature increases across the Qinghai-Tibet Plateau. Furthermore, concurrent with climate warming and enhanced monsoon influence, the spatial heterogeneity of ET has become increasingly pronounced across the region. Vegetation phenology on the Qinghai-Tibet Plateau is influenced not only by climate change but also regulated by elevation and geographic position. In high-elevation zones, vegetation growth is restricted by low temperatures and relatively limited precipitation, typically resulting in lower LAI values.  
The spatial distribution of interannual average GPP values for vegetation on the Qinghai-Tibet Plateau, simulated using the improved MODIS-PSN model from 2001 to 2022, shows a decreasing trend from southeast to northwest. The annual average spatial distribution and rate of change reflect the dynamic characteristics of ecosystem productivity, consistent with previous findings [48]. Overall, the changes in GPP exhibit significant spatial heterogeneity: The rate of change in the humid regions of the northeast and southeast is significantly positive, mainly distributed in wetland and forest ecosystems, with the maximum annual average rate of change reaching 12.40 gC/m\({}^{2}\)/year. In contrast, the central and southern regions show a decreasing trend, with the lowest rate of change at \(-1.61\) gC/m\({}^{2}\)/year, predominantly concentrated in alpine grasslands and desert regions.
# Free Vibrations and Flutter Analysis of Composite Plates Reinforced with Carbon Nanotubes
## 1 Introduction
[14] analyzed composites with high-volume fractions of CNTs, i.e., 11%, 14%, and 17%. [PERSON] et al. [19] investigated composite plates with CNT fractions of 11%, 14% and 17%. The current work was mainly inspired by the paper of [PERSON] et al. [8], where the composites with low CNT fractions, i.e., 0.5, 1, 2, and 3 wt%, but with the random distribution of the nanoreinforcement, were analyzed, and the paper of [PERSON] et al. [11], where the importance of the distribution (random or uniform) and the orientation of the nanoreinforcement and their influence on the properties of the nanocomposites were studied. The advantages of composites with uniform distribution of nanotubes are presented in many papers, for example [25; 26; 27; 28]. It has also been observed that the mechanical properties of nanocomposites deteriorate at higher carbon nanotube volume fractions due to the formation of CNT agglomerates, which act as stress concentrators [9]. Several issues, including eigenfrequencies, flutter, and divergence, are considered in the investigation of nano-reinforced composite structures subject to dynamic stability constraints. As mentioned above, it should be noted that a great number of studies have addressed the free vibration and flutter response of FG CNT/nanocomposite structures with a high-volume fraction of CNT; however, there are only a few studies on the flutter instability of classic CNT/nanocomposites with a low-volume fraction of CNT. To address the insufficient knowledge on dynamic instabilities of nanocomposite plates, the free vibration and flutter analysis on classical CNT/nanocomposite thin plates with uniformly distributed reinforcement and a low-volume fraction of CNT subjected to supersonic airflowis performed in this study. The present analysis considers the definition of the geometry and material properties of nanocomposite thin plates. The analytical approach used in the flutter investigation of composite panels is applied here to the supersonic analysis of nanocomposites. To demonstrate the rigor of the current research, the results are compared with those reported in the open literature. The influence of the aspect ratio, volume fraction, and boundary conditions on the CNT/nanocomposite behavior are presented.
## 2 Description of the Models
### Dynamic Model of HGRS  
The research in this paper is aimed at cumulative pitch deviations, which have long periods, and the motivation is to study the influence mechanism of cumulative pitch deviations on the mesh excitations and vibration spectrum characteristics of HGRS. Thus, it is unnecessary to select complex gear transmission device, and a single stage gear system can satisfy the requirement. In the published researches, a single-stage gear transmission device with transmission ratio of 1:1 is used for several times [23; 24; 27; 28; 29]. In order to avoid too large s computational effort, according to those published works, a HGRS with transmission ratio of 1:1 is selected as the research object. Figure 5 shows the structure diagram of a HGRS. Shaft 1 and shaft 2 are solid shafts where the driving and driven gear are located. Both shafts are composed of several shaft segments with different diameters and lengths. The parameters of the helical gear pair are given in Table 1. Each shaft is composed of 5 shaft segments. The outer diameters of shaft segments of the two shafts from left to right are 70 mm, 90 mm, 110 mm, 90 mm, and 70 mm, respectively. For shaft 1, the length of shaft segments from left to right is 100 mm, 110 mm, 220 mm, 110 mm, and 60 mm, respectively. For shaft 2, the length of shaft segments from left to right is 60 mm, 110 mm, 220 mm, 110 mm, and 100 mm, respectively. Considering shaft structure, gear and bearing positions, each shaft is divided into 13 elements, as shown in Figure 5. Three basic elements (gear mesh element, shaft element, and bearing element) are used to build the dynamic model of HGRS.  
Figure 5: Schematic diagram of HGRS.
# Development of a Spatial Heterodyne Terahertz Raman Spectrometer with Echelle Gratings
## 3 Experiment
### Food Additives Measurement Results  
Figure 4 shows the test results from terahertz Raman spectroscopy of a variety of food additives obtained in this work. Leucine is the basic unit for protein synthesis [15], and DL-leucine is often used as a nutritional additive [16]. Figure 4a shows the terahertz Raman spectrum of DL-leucine, in which the characteristic peaks of the samples can be identified clearly at 48.67 cm\({}^{-1}\) (1.46 THz), 56.67 cm\({}^{-1}\) (1.7 THz), 72.33 cm\({}^{-1}\) (2.17 THz), and 86.7 cm\({}^{-1}\) (2.6 THz). The two characteristic peaks at 72.33 cm\({}^{-1}\) (2.17 THz) and 86.7 cm\({}^{-1}\) (2.6 THz) mainly represent the rotation and vibration of the hydrogen bonds in the molecular structure [17]. Figure 4b shows the terahertz Raman spectrum of DL-tartaric acid, which is commonly used as a food acid flavor agent. The characteristic peak at 40 cm\({}^{-1}\) (1.2 THz) was generated by the interactions between the molecules, and the characteristic  
Figure 3: (**a**) Comparison of terahertz Raman spectra of salicylic acid; (**b**) comparison of terahertz Raman spectra of benzoic acid; (**c**) terahertz Raman spectrum of gallic acid; (**d**) terahertz Raman spectrum of p-aminobenzoic acid.  
peak at 60.3 cm\({}^{-1}\) (1.81 THz) represents the collective vibration of the C-C bonds and the carboxyl torsional vibration [18]. DI-threonine is an essential amino acid used in nutritional supplements, and its terahertz Raman response is shown in Figure 4c. L-malic acid is an essential organic acid for the human body that can be obtained by extraction from fruit and represents a new generation of food souring agents. During the red wine fermentation process, the transformation from L-malic acid into L-lactic acid also determines the quality of the red wine [19]. Figure 4d shows the terahertz Raman spectrum of L-malic acid. As an unsaturated binary carboxylic acid, fumaric acid is widely used as an acidity regulator in meat processing. Figure 4e shows the terahertz Raman spectrum of fumaric acid. Glycine is one of the simplest amino acids, with chemical properties that allow it to be used in food flavorings and food preservatives. Figure 4f shows the terahertz Raman spectrum of glycine, where the characteristic peaks observed at 80 cm\({}^{-1}\) (2.4 THz) and 84.3 cm\({}^{-1}\) (2.53 THz) correspond to molecular vibrations [20].  
Figure 4: _Cont_.  
Analysis of the samples' test results, described above, verifies that the system demonstrates a high spectral resolution performance; the samples' test results are more accurate, almost all the characteristic peaks of the samples in the terahertz Raman band can be measured, and the results can provide some theoretical support for the detection and screening of food additives.
## Abbreviations  
* NIB-IoT Narrowband Internet of things
* LEO Low Earth Orbit
* CE Coverage Enhancement
* RACH Random Access Channel
* NGSA-II Non-dominated Sorting Genetic Algorithms-II
* ISL Inter-Satellite Link
* D2D Direct to Device
* NTN Non-terrestrial Network
* MAC Medium Access Control
* RLC Radio Link Control
* PDCP Packet Data Convergence Protocol
* RRC Radio Resource Control
* DMRS Demodulation Reference Signal
* GNSSs Global Navigation Satellite Systems
* HARQ Hybrid Automatic Repeat Request
* SINR Signal-to-Interference-plus-Noise Ratio
* TA Time Advance
* RSRP Reference Singal Receiving Power
* PDF Probability Distribution Function
* LOS Line of Sight
* NLOS Non-line of Sight
* RAR Random Access Response
* Round Trip Delay
* PSO Particle Swarm Optimization
* 3 GPP 3 rd Generation Partnership Project
# Reducing Video Coding Complexity Based on CNN-CBAM in HEVC
## 4 Conclusions and Feature Works
**Abbreviations**  
**Full Name**  
CNN & Convolution neural network  
CU & Coding unit  
HEVC & High-efficiency video coding  
CBAM & Convolution block attention module  
CNN-CBAM & Convolution neural network convolution block attention module  
BD-PSNR & Bjontegaard delta PSNR(Peak Signal-to-Noise Ratio)  
BD-BR & Bjontegaard delta bitrate  
VVC & Versatile video coding  
QTMT & Quad tree-based merge and transform  
RDO & Rate-distortion optimization  
GPU & Graphics processing unit  
HM & High-efficiency video coding test model  
CTU & Coding tree unit  
QP & Quantization parameter  
RD & Rate-distortion  
PU & Prediction unit  
LCU & Large coding unit  
ML & Machine learning  
SVMs & Support vector machines  
RFs & Random forests  
FCon & Full convolution  
Con & Convolution  
MP & Maximum pooling  
S & Stride  
2D & Two [PERSON]  
MLP & Multi-layer perceptron  
CPH & Coding unit partition of high efficiency video coding  
UHD & Ultra-high definition  
JCT-VC & Joint collaborative team on video coding  
FoM & Figures of merit.
# In-Memory Caching for Enhancing Subgraph Accessibility
## 1 Introduction
Furthermore, since the existing studies replaced a large amount of graphs at once, it even cached subgraphs that were unlikely to be accessed. The existing studies did not consider neighbor vertices employed together when subgraphs were used during graph data processing. In general, frequently used subgraphs are likely to be used again. Thus, a high-usage subgraph should have a higher survival rate in the memory than that of a low-usage subgraph. Moreover, when graph data were cached in the memory, the neighbor vertices were all cached. For example, for a famous person on Facebook who has tens of millions of friends, the neighbor friend information must be stored in memory. If access to the vertex with many neighbor neighbors occurs frequently, memory can be overloaded or many input/outputs (I/Os) may occur in the memory. In this paper, we propose a two-level caching strategy that stores subgraphs that are likely to be accessed in consideration of the usage pattern of subgraphs to prevent the caching of low-usage subgraphs and frequent subgraph replacement in the in-memory. A cache level is divided into two levels: a used cache that stores a subgraph by assigning a weight according to the frequently used subgraph pattern and a prefetched cache that stores the neighbor subgraph of a recently used subgraph. Subgraph usage patterns are extracted by means of the query management table and Frequent Pattern-tree (FP-tree) to extract and manage subgraph usage patterns by utilizing the usage history information of subgraphs. The neighbors connected to edges with a high history information value among neighbor vertices during the current query are loaded in the prefetched cache utilizing the history information of the edges. We also propose a strategy that manages the cached subgraph in each cache and replaces the cached subgraph that is unlikely to be used with a new subgraph when the memory is full. The subgraph of the used cache is managed through a time-to-live (TTL) value that is assigned when the subgraph is assigned to the memory. It uses a strategy that replaces the subgraph with a low TTL value with the newly loaded subgraph. The subgraph in the prefetched cache is managed by the \"first-in, first-out\" (FIFO) strategy. When the memory is full, the first-in subgraph is replaced with a newly cached subgraph. Once a hit occurs at the prefetched cache, the subgraph is migrated to the used cache and managed after assigning the TTL value. This paper is organized as follows. Section 2 describes the existing in-memory graph data cache management schemes. Section 3 introduces the in-memory caching and management scheme using subgraph patterns and graph usage history information. Section 4 verifies the performance of the proposed scheme through experiments. Finally, Section 5 presents the conclusion and future study direction of this paper.
# Economic Superiority of PIP Slip Joint Compared to Conventional Tubular Joints
## 2 Methodology
### Performance Advantage  
The bar chart presented in Figure 9 illustrates the percentage differences in payback period, NPV, and LCOE, which are the three major parameters for comparing the PIP slip joint compared to the bolted flange joint and grout joint. This data highlights the superior financial performance of the PIP slip joint in offshore wind applications.  
The PIP slip joint has a payback period that is 5.34% shorter than that of the bolted flange joint and 5.72% shorter than the grout joint, indicating faster investment recovery at 2.916 years, which helps minimize financial risk. Additionally, its NPV, at EUR 39.559 M, is 1.30% higher than that of the bolted flange joint and 1.40% higher than the grout joint. This suggests enhanced long-term profitability, driven by reduced operational costs and improved structural reliability.  
Furthermore, the LCOE of the PIP slip joint, at 0.014, is 1.63% lower than that of the bolted flange joint and 1.76% lower than the grout joint, underscoring its cost efficiency in energy production--a critical factor for the competitiveness of offshore wind energy.  
These findings support the PIP slip joint's leadership in IRR, BCR, and ROI, positioning it as the optimal joint type for maximizing economic returns and sustainability in offshore wind projects. This provides a compelling case for its adoption in future developments.  
The findings of this study regarding the economic and operational benefits of PIP slip joints are consistent with conclusions drawn from existing technical reports and the peer-reviewed literature. For instance, a prior study demonstrated the practical viability of slip-joint systems, highlighting their advantages in terms of simplified installation and decommissioning processes, as well as reduced environmental footprint [21]. Similarly, another study identified the growing interest in alternative connection technologies, such as PIP joints, within the offshore wind sector as part of broader trends towards cost reduction and structural efficiency [22]. However, despite their promising attributes, PIP slip joints still face several limitations. These include a lack of long-term fatigue data under combined loading conditions, limited design standardization within current regulatory frameworks (e.g., DNV-ST-0126 and IEC 61400-3-1), and potential challenges related to manufacturing tolerances and installation alignment [4; 49]. These limitations underscore the need for  
Figure 9: Performance advantage for different joint types.  
further field validation, industry-specific guidelines, and full-scale demonstration projects to support widespread adoption. Nonetheless, the present analysis demonstrates that, when evaluated through a lifecycle cost perspective, PIP slip joints offer a technically and economically viable alternative for offshore wind foundation connections.
# Investigation of In Situ and Ex Situ Passivation of Pyrophoric Uranium-Niobium Alloy Powder
## 3 Results and Discussion
### TEM and Oxide Thickness  
To further investigate the oxide layers of the powders, spherical particles were sectioned with FIB milling to prepare a thin lamella suitable for TEM. Micrographs (Figure 4a,b,d,e) and elemental composition maps (Figure 4c,f) were obtained by STEM/EDX analysis, confirming the presence of the oxide layer on both the ex situ and in situ-passivated powder.  
The oxide layer thickness on six ex situ-passivated particles was measured to range between 20 and 30 nm over a 3 \(\upmu\)m length of the lamella, with a few localized spots as thin as 12 nm (Figure 4a-c). In contrast, the oxide layers on four in situ-passivated particles (5 SLPM of passivation gas) all exhibited localized regions with thicknesses in the hundreds of nanometers, interspersed with significantly thinner regions measuring as thin as 5 nm. Some particles had a maximum observed thickness of approximately 100 nm, while others had thicknesses over 200 nm, corroborating a wide disparity in oxide thickness from particle to particle.  
The large range of oxide thicknesses on any given in situ-passivated sphere likely arose from rapid oxide nucleation and growth initiated at high temperatures, resulting in uneven surface coverage. After cooling, surfaces not already covered by thick oxide formed at high temperatures continued to be exposed to the passivating gas at lower temperatures until collection, which would explain why the regions in between the thicker areas have oxide thicknesses similar to or even thinner than the ex situ powder. The somewhat bimodal distribution of oxide thicknesses, with some areas heavily oxidized and others not, leaves parts of the particle surface highly reactive. This explains why in situ passivation with lower levels of passivating gas was not consistently effective, despite causing a bulk color change in the powder.  
Moreover, because some particles received less overall passivation than others, there must be enough passivation gas to ensure the least passivated particles are sufficiently passivated. Because any small fraction of a sample that is reactive enough to undergo autoignition will cause the whole sample to ignite, there must be a relatively large excess of oxygen introduced during in situ passivation to ensure that even the thinnest regions have a sufficiently thick oxide layer.  
In contrast, ex situ-passivated powders demonstrated more consistent and uniform oxide layer thickness, effectively mitigating pyrophoricity despite having thinner oxide layers. This indicates that the uniformity and continuity of oxide coverage are more critical to passivation effectiveness than simply achieving thicker average oxide layers. This uniformity ensures that no regions of the powder remain under-passivated. Consequently, assessments of powder passivation effectiveness should not rely solely on bulk oxide thickness measurements; rather, localized characterization of oxide uniformity is necessary.
## 4 Description of the System
### The Vehicle Positioning System (VPS)  
The system uses a GPS receptor. The data obtained are the vehicle's position (latitude, longitude and elevation), velocity, the quality of readings, which is a function of the satellite coverage, and the instant in time at which the universal time coordinates (UTC) were measured. It is important to note that GPS units are commercially available and provide geographical position readings with an error that is a function of different factors: climate conditions at the time of data acquisition, terrestrial curvature radius and the presence of random selective error. In general, assuming there is no random selective error, the maximum positioning error for GPS is 100 m. The connection with the OBC is made through an asynchronous interphase with the following communication parameters:  
* Baud rate: 9,600.
* Data Bits: 8.
* Stop Bits: 1.
* Handshake: no.
* Parity: no.  
The protocol used for communication between the GPS and the OBC uses a data packet with the following structure:  
\(>\)ABB{C}[;ID=DDDD][;*FF]\(<\),  
where:  
\begin{table}
\begin{tabular}{l l} \hline \hline
**Field Name and (Source Field in LNM Message)** & **Type and Size** \\ \hline Universal Time Coordinated (C1) & Integer 4 bytes \\ Latitude (C2) & Float 4 bytes \\ Longitude (C3) & Float 4 bytes \\ Elevation (C4) & Float 4 bytes \\ Vertical velocity (C5) & Float 4 bytes \\ Horizontal velocity (C6) & Float 4 bytes \\ Source of the reading (C12) & Char 1 byte \\ Age of reading (C13) & Char 1 byte \\ Vehicle (On Board system parameter) & Integer 2 byte \\ \hline \hline \end{tabular}
\end{table}
Table 1: PR structure.