esa-sceva/satcom-chunk-collection huggingface dataset:
# Physical Layer Definition for a Long-Haul HF Antarctica to Spain Radio Link
## 5 Physical Layer Proposal
### Frame Structure
#### 5.3.1 Sounding Frame Structure  
The narrowband sounding frame (see Figure 12a) starts with a synchronization word, in this case, a PN m-sequence of 255 chips, as described in [30], with an upfactor of 6 samples/chip, as used in [8,10,18]. After that, 2 s of silence followed by 10 s of narrowband tone transmission, and followed by 2 s of silence again. The idle periods of silence are used to measure the noise, and obtain a good estimation of SNR.  
The wideband sounding frame (see Figure 12b) starts with the same synchronization word as the narrowband sounding, a PN m-sequence length 255 chips [30] with upfactor of 6 samples/chip. 5.1 s of wideband data is transmitted, using a PN m-sequence of 255 chips of type m [28,29] with an upfactor equal to 10 samples/chip, obtaining a total of 200 consecutive sequences with a bandwidth of 10 kHz. This amount of data allows the system to work with the channel response matrix and, afterwards, with the scattering function. From these two functions the delay spread and the Doppler spread of the channel will be obtained, as well as the SNR for wideband and the number of paths.  
Finally, the data frame structure will vary depending on if it is working in the daytime configuration or in nighttime configuration. Despite this, as seen in Figure 12c,d, the frame starts with a synchronization part, containing three m-sequences of 255 chips with an upfactor of 6 samples/chip, using a total time of 45.9 ms of synchronization time (see Section 4.3). No channel coding or interleaving will be applied to the data, as the retransmission is the used error control (see Section 4.2).
###### Abstract  
To improve the synchronization accuracy of dual motors under external disturbances, this paper proposes a cross-coupling control strategy based on an improved global fast terminal sliding mode control (GFTSMC) and disturbance observer (DOB). In practical applications, dual-motor systems are often affected by external disturbances, leading to synchronization errors between the motors, which in turn affect the system's stability and accuracy. First, for single-motor control, this paper uses the improved GFTSMC method to design a speed loop, enhancing the tracking accuracy and dynamic response of the individual motor by optimizing the sliding surface. Then, the improved GFTSMC is combined with a cross-coupling strategy to effectively solve the synchronization problem of dual motors. The cross-coupling strategy coordinates the operation of the two motors, reducing the speed deviation between them, thus improving synchronization accuracy and enhancing the system's disturbance rejection capability. Moreover, the DOB is used to precisely estimate the frictional torque, and compensating for these disturbances improves the system's robustness and stability. The results show that the proposed control method significantly improves the speed synchronization of the dual motors and exhibits excellent dynamic performance, effectively coping with complex external disturbances.  
Keywords:dual motors; cross-coupling control; speed synchronization; GFTSMC; disturbance observer; frictional torque +
Footnote †: journal: Applied sciences
# An Identity-Based Anti-Quantum Privacy-Preserving Blind Authentication in Wireless Sensor Networks
## 2 Preliminaries  
### The Applications for BS  
With the development of big data, which has the properties of volume, variety, velocity, value, veracity, variability, viscosity, and virality, organizations deploy their services such as e-payment and e-voting systems etc. to the cloud [16; 17; 18]. In e-payment and e-voting systems, BS scheme plays an important role for that BS scheme can protect user's anonymous instead of encrypting all the data and searching on the ciphertexts [19; 20; 21]. In addition, scholars proposed some methods to protect security in the cloud [22; 23; 24; 25], which can provide us with new methods to make our scheme in practice.  
Meanwhile, scholars proposed some methods to detect complex event analysis, which can be used to improve the security of these services and applications in the cloud [26; 27]. We will briefly describe e-payment and e-voting systems as follows:  
E-payment system: \(A\), \(B\), \(T\), and \(Ba\) are denoted as buyer, merchandiser, trusted third party, and bank respectively. Then the e-payment process is presented in Figure 1[4]. In the beginning, \(T\) will produce and deliver keys for all the \(Bas\), \(A\), \(B\) will open a new account from their \(Ba\) respectively. The details are as follows:  
\(A\) logins into his account, draws e-cash \(m\) from the \(Ba\)-\(A\), blinds \(m\) by using blind factor \(f\), and then obtains \(m^{{}^{\prime}}\). The \(Ba\)-\(A\) signs on \(m^{{}^{\prime}}\), and sends the signature \(\sigma^{{}^{\prime}}\) to \(A\)[28]. \(A\) unblinds the signature by using \(f\) and obtains \(\sigma\). \(A\) sends the tuple \(<m,\sigma>\) to \(B\). \(B\) verifies whether it is valid or not, if it is, he sends the tuple to \(Ba\)-\(B\). The \(Ba\)-\(B\) deposits the money on \(B\)'s account.  
E-voting system: the voter, registrar, administrator, tallier, nominators, and validator are denoted as \(vo\), \(re\), \(ad\), \(ta\), \(no\), and \(va\) respectively. The protocol is presented in Figure 2[4]:  
\(vo\) sends his id to a \(re\), the \(re\) checks whether the \(vo\) is valid. If he is, the \(vo\) can send two \(nos\) to \(ad\), the \(ad\) will check whether they are valid. If they are, the \(vo\) can choose a ballot \(m\), blind it by using blind factor \(f\), and then get the blinded message \(m^{\prime}\). \(m^{\prime}\) will be sent to a \(va\), the \(va\) signs on it and sends the signature \(\sigma^{\prime}\) to the \(vo\). The \(vo\) unblinds \(\sigma^{\prime}\) by using blind factor \(f\), and gets a signature \(\sigma\). The \(vo\) sends \(m,\sigma\) to a \(ta\), the \(ta\) will count all his ballots and store the results to a voting database.  
Figure 1: Blind authentication in e-payment system.
# Calibration of Camera and Flash LiDAR System with a Triangular Pyramid Target
## 4 Experiments
### Simulation
#### 4.1.5 Performance with Respect to Number of Frames  
As described in Section 3.2.2, our method can calibrate the extrinsic parameters through one single capture. However, more frames of the camera and LiDAR can provide more information of the target. In this experiment, we simulate 20 frames of the camera and LiDAR, and randomly select several frames to figure out the calibration result. The number of frames varied from 1 to 9, and for each number, we conduct 300 independent tests. The noise level of pixel noise is set to \(\sigma=0.5\) pixel, and the \(\sigma\) of point cloud noise is set from 10 mm to 50 mm separately. Figures 8 and 9 plot the average absolute errors of rotation and translation. It is shown that, as the number of frames increases, the rotation and translation errors decrease obviously. However, when there are more than six frames, the decrease in the measurement error is not obvious. So, it is wise to use a suitable number of frames to obtain a precise result.  
Figure 8: Average absolute error of rotation for different number of frames.  
Figure 7: The relation between absolute errors and pixel noise level after optimization: (**a**) absolute errors of rotation and (**b**) absolute errors of translation.
# Tourism Sentiment Chain Representation Model and Construction from Tourist Reviews
## 2 Related Works
### Methods for Recommending Tourist Routes  
Tourism route recommendation remains a central research focus in tourism behavior studies [26; 27]. Methodologically, existing approaches fall into two major categories: attraction attribute-driven [28; 29] and tourist behavior-driven [30; 31; 32] strategies. (i) Attraction attribute-driven methods focus exclusively on transit costs, such as road distances and transit times between attractions [33]. [PERSON] et al. applied impedance models to compute shortest-path routes based on geographic coordinates [34]. While effective in reducing spatial inefficiencies, these methods often neglect thematic dissimilarities that influence experiential coherence. (ii) Tourist behavior-driven methods leverage visitation frequency and sequential patterns to inform recommendations [35]. [PERSON] et al. introduced a travel sequence similarity measure by modeling tourist movement as event sequences, enabling the generation of novel itineraries through cross-city comparisons [36]. [PERSON] et al. enhanced ant colony optimization algorithms by incorporating user sentiment and sequence similarity into heuristic functions, thereby recommending highly visited routes [37]. However, these popularity-centric strategies tend to overemphasize mainstream attractions, overlooking both spatial efficiency and the latent experiential value of niche destinations.  
Recent efforts in tourism route recommendation have explored the integration of multi-modal information through techniques such as graph modeling, path search algorithms, and intelligent optimization strategies. For instance, [PERSON] et al. proposed a weighted scoring framework that incorporates user-specific preferences and attraction attributes to generate personalized itineraries [30]. [PERSON] et al. further developed a tourism route graph model integrated with a random walk mechanism to simulate transitions between attractions, employing an enhanced ant colony optimization algorithm for route planning [38]. Additionally, Simulated Annealing (SA), due to its robust global search properties, has been applied to combinatorial optimization in tourism routing; for example, [PERSON] et al. utilized an Adaptive Neighborhood Simulated Annealing (ANSA) algorithm to recommend sightseeing locations and activity suggestions tailored to individual tourist preferences [39].  
Despite their contributions to multi-criteria modeling, these approaches suffer from three major limitations. First, they lack effective quantification of semantic-emotional associations--such as thematic coherence and affective alignment--between attractions. Second, their weighting schemes tend to be static and insufficiently responsive to the heterogeneous and evolving preferences of diverse tourists. Third, most optimization strategies are confined to local search paradigms, limiting their capacity to identify globally optimal paths within the solution space.
## 5 Evaluation Measures
### Usability
#### 5.2.1 Satisfaction
In addition to multiple-item scales, qualitative methods such as thinking aloud or interviews are also recommended [119]. This would allow for a profound understanding of context and the extent to which satisfaction resulted from the explanation design or other contextual factors. In addition, conducting expert case studies could be an alternative approach as experts, in contrast to laypersons, possess extensive knowledge of the system's domain, enabling them to provide more thorough and insightful evaluations [120]. Moreover, additional objective measures, such as eye movement, heart rate variability, skin conductance, and jaw electromyography showing positive emotions, have also been used in research to measure user satisfaction [121; 122].
# Performance Evaluation of GPS Auto-Surveying Techniques
## 2 Materials and Methods  
### GPS Observables  
In this paper, the only GPS observables used are the pseudorange and carrier phase as given by a GPS receiver capable of raw data output.
## 3 Stratum-Foundation Pit-Station-Track Interaction Model
### Model Calculation Parameters and Construction Simulation Process
#### 3.2.2 Structural Parameters  
After collecting and consulting the structural design data of new projects and built subway stations, it was determined that the concrete strength of the enclosure structure, temporary concrete column pile foundation of the foundation pit, concrete internal support, subway entrance and exit and other structures is C30, and the main structure of the station, tunnel and track slab is made of C40 strength concrete. Anchor rods and steel lattice columns are made of steel. The structural parameters are shown in Table 6.  
The new foundation pit is divided into five stages of excavation, and the depth and earthwork of each stage are shown in Table 7.  
The construction simulation steps include initial in situ stress, foundation pit enclosure structure and temporary column construction, five-layer soil excavation and support and  
Figure 21: Schematic diagram of internal station simulation.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Serial** & **Name** & **Thickness (m)** & **Density** (g/cm\({}^{3}\))** & **Internal Friction** & **Force of** & **Poisson** & **Elastic** \\
**Number** & **Name** & **Thickness (m)** & **Angle (\({}^{\circ}\))** & **Angle (\({}^{\circ}\))** & **Cohesion** & **Ratio** & **Modulus** \\ \hline
1 & Miscellaneous & & & & & & \\ soil filling & 2.0 & 1.70 & 5 & 10 & 0.3 & 12.0 \\
2 & Silty clay & 5.0 & 1.96 & 15 & 35 & 0.3 & 40.0 \\
3 & Fine Sand & 8.0 & 1.95 & 28 & – & 0.3 & 75.0 \\
4 & Pebble\(\copyright\) & 15.0 & 2.10 & 35 & – & 0.25 & 135.0 \\
5 & Pebble\(\copyright\) & 32.0 & 2.15 & 40 & – & 0.25 & 180.0 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Finite element model to simulate soil parameters.  
anchor rod erection, with a total of 42 steps. The construction simulation process is shown in Table 8.
## 4 Discussion
### Effect of Land Use Change on Net Ecosystem Production  
The relatively high NEP in the ES sites was related to lower heterotrophic respiration coupled with a relatively high belowground NPP (Table 4). We estimated the carbon losses from peat forest conversion to early seal may reach an estimated 4259 Mg CO\({}_{2}\) e ha\({}^{-1}\) over 25 years, which includes incidences of numerous peat fires [4]. Combining these data, early seal sites are significant net sources of greenhouse gasses (120 Mg CO\({}_{2}\) e ha\({}^{-1}\) yr\({}^{-1}\)).  
Compared to other wetlands, the NEP of peat forests in this study was lower than that of tropical mangroves [50; 51; 52; 53] but higher than the Siberian peat forests [54] (Figure 6). The high NEP of mangrove ecosystems has been attributed to its high NPP due to its nutrient-rich ecosystem and low heterotrophic respiration due to saturated soil within a tidal environment [17; 53]. The low NEP of Siberian peat forests has been attributed to a limited growing season [55]. These findings are similar to our conclusion that the rate of NPP is the primary driver of NEP and that the changes in land use affect NPP to a greater extent than respiration.  
In contrast with the NEP reported for peat oil palm estates in Malaysia [56], we found that oil palm estates of our study sites are significant sources of greenhouse gases NEP = \(-\)25.1 Mg CO\({}_{2}\) e ha\({}^{-1}\) yr\({}^{-1}\)). The palm estates of our study had a lower annual NPP (13.6 Mg CO\({}_{2}\) e ha\({}^{-1}\) yr\({}^{-1}\)) than that reported in [56] (44 Mg CO\({}_{2}\) e ha\({}^{-1}\) yr\({}^{-1}\)). This difference may be due to methodological differences.  
We estimated that land cover change in peat forest landscapes to logged forests, early seal sites, and oil palm estates result in net emissions of about 10.9, 1.7, and 35.9 Mg CO\({}_{2}\) e ha\({}^{-1}\) yr\({}^{-1}\), respectively. These results are lower than current IPCC default values for emission from drained peat on forest land, grassland, and oil palm estate (19.4, 35.2, and 36.7 Mg CO\({}_{2}\) ha\({}^{-1}\) yr\({}^{-1}\)) [57]. However, these differences are likely related to different methodologies since our NEP includes peat decomposition (respiration) and NPP. The IPCC values represent either historical (peat subsidence approach) or present (CO\({}_{2}\) fluxes) sources, excluding peat fires' impacts [57].
# 4D Printing of Multicomponent Shape-Memory Polymer Formulations
## 4 Vat-Photopolymerization Based 4D Printing
### Multi-Photon Polymerization (MPP) of SMPs  
Multi-photon polymerization (MPP) is a direct laser writing technology that uses an ultrafast pulsed laser to generate a very high flux of photons in a small volume over a very short period of time [132]. Typical systems use green light (\(\lambda\sim\) 515 nm or 532 nm), near-infrared light (\(\lambda\sim\) 780 nm, 1064 nm, or 1080 nm), or a combination of these wavelengths. MPP techniques allow for the voxel-by-voxel writing of complex structures with critical dimensions of micro/nano scale size (with sub-micrometer resolution) into a liquid resin by scanning a tightly focused femtosecond-pulse laser beam. Unlike other stereolithographictechniques, MPP can freely cure solid polymer in the resin vat, eliminating the need for material deposition in a layer-by-layer manner [132; 133].  
[PERSON] et al. demonstrated the 4D printing of trSMPs at sub-micron length-scales using two-photon lithography [134]. They showed a remarkable relationship between color transmittance and the nanostructure of 4D printed trSMPs. The SMP photoresist based on VeroClear (Stratasys Inc., Edina, MN, USA) was used to 4D print submicron-scale grids. The grids transmitted only a limited range of wavelengths when illuminated by white light. When the structure was programmed by heating and deforming above its \(T_{g}\) of 80 \({}^{\circ}\)C, it achieved an \"invisible\" state capable of transmitting visible light of all wavelengths. After reheating above \(T_{g}\), the nanostructure recovered it original state and again permitted only a certain range of wavelengths to pass through, as the spectrum of wavelengths was scattered differentially by the grid. By varying the printing parameters during additive manufacturing (laser power, write speed, nominal grid height), different colors could be easily realized in the parts and switched by the programming process (Figure 14).  
In another report, [PERSON] et al. demonstrated the 4D printing of trSMP-based microstructured stents with minimum features of 5 \(\upmu\)m by using the MPP technique referred to as direct laser writing (DLW) [135]. The limitation associated with printing trSMPs at the microscale were overcome by using an indirect 4D printing approach. In the first step, high-resolution micromolds were produced by DLW of a photoresist. These micromolds were then infused with a photo-sensitive trSMP resin, which was cured by UV irradiation, followed by dissolution of the photoresist-based micromold to yield a microstructured part. Following programmed deformation, the stent-shaped trSMP microstructures recovered their initial shape when the temperature was raised. The printing of microstructured parts could be helpful in the fabrication of soft microrobots to solve medical issues.
# A Psychoacoustic-Based Multiple Audio Object Coding Approach via Intra-Object Sparsity
## 2 Proposed Compression Framework
### Downmix Processing  
After extracting the dominant TF instants \(\hat{\mathbf{S}}_{q}\), source \(1\) to source \(Q\) only contains the perception significantly MDCT coefficients of all active audio objects. However, each source include a number of zero entries, hence, the downmix processing must be exploited which aims to redistributing the nonzero entries of the extracted TF instants from \(1\) to \(L\) in the frequency axis to generate the mono downmix signal.  
For each active source \(q\), a \(k\)-sparse (\(k=NPTF_{q}\)) approximation signal of \(S_{q}(n,l)\) can be attained by rearrange \(\hat{S}_{q}\) in the original position, expressed as:  
\[\widetilde{S}_{q}(n,l)=\begin{cases}S_{q}(n,l),&\text{if }l\in\mathbf{I}_{q}\\ 0,&\text{otherwise}\end{cases} \tag{9}\]  
The downmix matrix is denoted as \(\mathbf{D}_{n}\equiv\left[\widetilde{\mathbf{S}}_{1},\widetilde{\mathbf{S}}_{2},\cdots, \widetilde{\mathbf{S}}_{Q}\right]^{\mathsf{T}}\), where \(\widetilde{\mathbf{S}}_{q}\equiv\left[\widetilde{S}_{q}(n,1),\widetilde{S}_{q}( n,2),\ldots,\widetilde{S}_{q}(n,L)\right]\) and \({}^{\mathsf{T}}\) is the transpose operation. This matrix is sparse matrix containing \(M\times L\) entries. Through a column-wise scanning of \(\mathbf{D}_{n}\) and sequencing the nonzero entries onto the frequency axis according to the scanning order, the mono downmix signal and side information can be obtained via Algorithm 2.  
Figure 2 indicates the demixing procedure in accordance with an example of eight simultaneously occurring audio objects. Each square represents a time-frequency instant. The preserved TF components for each sound source (a total of 8 audio objects in this example) are represented by various color-block and shading.  
Furthermore, the above-presented downlink processing guarantees the redistributed TF components locating in the nearby frequency position as their original position, which is prerequisite for subsequent Scalar Quantized Vector Huffman Coding (SQVH). Consequently, the downlink signal \(\mathbf{d}_{n}\) can be further encoded by SQVH technique. Meanwhile, the side information compressed via the Run Length Coding (RLC) and the Golomb-Rice coding [19] at about 90 kbps.
## 4 Results
### Ground Deformation
The time series at TS2 (orange line in Figure 8a) shows that the deformation was approximately 0 mm before September 2020, but deformation tended to appear afterward. According to the definition of reactivated landslides, this deformation pattern accords with a reactivation phenomenon. The maximum annual deformation velocity in the study area appeared at TS1 and the accumulated deformation reached approximately 167.1 mm at the end of the observation period (Figure 8a). The deformations at MPs TS1, TS3, TS5, TS6, and TS7 increased linearly with time (Figure 8a), suggesting that these slopes are in the secondary creep stage and the index of instability is in a limit equilibrium stage [31]. According to the inverse-velocity failure model, these slopes are not expected to fail as long as there is no strong impact such as intense rainfall and earthquake [62; 69]. The deformation time series at TS2, TS6, TS7, TS8, and TS9 obtained from the descending data set (Figure 8b) show similar trends as those from the ascending data set (Figure 8a). However, the displacement at TS2 before September 2020 fluctuated between 0 and \(-\)40 mm with the descending data set (Figure 8b) rather than around 0 mm with the ascending data set (Figure 8a). This might suggest the heterogeneous displacement on the slope as the MPs in different data sets are not located exactly at the same point because of the variable satellite-slope geometric relationships.