esa-sceva/satcom-chunk-collection huggingface dataset:
# Food and Drinking Water as Sources of Pathogenic Protozoans: An Update
## 9 Cyclospora cayetanensis  
Cyclospora is an oocyst-forming protozoan belonging to the clade Sar Alveolata, phylum Apicomplexa, class Conoidasida, subclass Coccidia, family Eimeridae [2]. Currently, nineteen _Cyclospora_ species have been reported to cause disease in various animals, but only _C. cayetanensis_ was associated with human disease [6; 235]. However, a recent study on the genotyping of thousands of _Cyclospora_ isolates from the USA and one from China, based on sequencing of two mitochondrial and six nuclear genetic loci, reported that at least three genetic lineages of _C. cayetanensis_ were responsible for human cyclosporias--Lineages A and B, which caused outbreaks in North America, and Lineage C from Henan Province, China. The reclassification of Lineage A as C. _cayetanensis_, Lineage B as the novel species _C. askfordi_, and Lineage C as the novel species _C. henanensis_ was proposed [236].  
The _C. cayetanensis_ life cycle starts with the release of non-infectiveocysts with the feces of infected individuals. These populate in the environment and become infectious after days or weeks from release at 22 \({}^{\circ}\)C to 32 \({}^{\circ}\)C [237; 238]. The sporulatedocysts contain two ovoid sporocysts, each containing two sporozoites, which are released in the gastrointestinal tract when ingested and invade the epithelial cells of the small intestine [235; 239]. Asexual and sexual multiplication are analogous to those described for _Cryptosporidium_ species [235]. There is still little information on the infective dose, the environmental conditions that favor oocyst persistence and sporulation, and reservoir existence [235; 239].
# Implementation of a Topology Independent MAC (TiMAC) Policy on a Low-Cost IoT System
## 4 The Proposed System
### TDMA Parameters  
On the one hand, low-cost devices and the elements comprising them ensure a low price for the final system. On the other hand, several limitations regarding frame timing parameters have to be taken into account when implementing the TDMA protocol on the selected ISM Band (of 433.050-434.790 MHz) using low-cost devices. More specifically, such limitations are: (i) nodes' internal clock may deviate significantly [33]; (ii) the interference on the selected band may be high [34; 35]; and (iii) the low-cost transmitter's accuracy and receiver's sensitivity may be reduced.  
In order to tackle the effects and drawbacks of the above limitations, some countermeasures are taken. For avoiding collisions occurring due to the clock drifts, each time slot (ts\({}_{i}\)) of the TDMA frame is set to last for a considerably long period (i.e., 500 ms), whereas a 300 ms long guard time (t\({}_{g}\)) is introduced between them for the same reason. For achieving the synchronization needed, at the beginning of each frame, nodes are allowed to get synchronized during a time period of 2000 ms (st). At the end of the frame, one more guard period, the frame guard period, is considered lasting 500 ms (t\({}_{fg}\)), thus allowing for further node's operations (e.g., sensing, message processing) to take place. The complete TDMA frame of the implemented policy is depicted in Figure 4.  
Figure 3: The wiring between the Arduino and the RF modules that implements the device for both transmission (i.e., Tx-module data connected to pin 12) and reception (i.e., Rx-module data connected to pin 12). The antenna (ANT) along with the power supply pins (i.e., GND and VCC) are also depicted.
# O2O: An Underwater VLC Approach in Baltic and North Sea
## 2 System Model  
In this proposed system model, we consider the transceivers as a source node (\(s\)) that transmits the optical signal from the Baltic sea towards the North ocean-based destination (\(d\)) within strong channel conditions depicted in Figure 2. It is assumed that the communication system is modeled under IM/DD technique through the OOK modulation scheme. In the proposed system model the signal propagation depends on the physical parameters of the experimental setup, such as electrical to optical conversion efficiency (\(\eta\)) and photo-detector responsivity (\(R\)) of photo-diode at the receiver end. Therefore, the received signals at the destination are given as,  
\[\begin{split} y=R\eta(& I+I_{b})x+n\\ &=R\eta Ix+n,\end{split} \tag{1}\]  
where \(I\) and \(I_{b}\) are the received signal light intensity and ambient light intensity of the VLC link, respectively. Additionally, \(x\) is defined the information transmission symbol along with the AWGN noise \(n\) with zero mean and \(\sigma^{2}\) variance. It is noteworthy that the interference from \(I_{b}\) can be effectively filtered by the optical filters. Moreover, optical-to-electrical conversion efficiency can be written as follows [19],  
\[\eta=\eta_{q}T_{0}\frac{q\lambda}{h\
u}, \tag{2}\]  
where \(\eta_{q}\), \(q\), \(\lambda\), and \(h\) are denoted as the quantum efficiency of the photo-detector, electron charge, the signal wavelength, and [PERSON]'s constant. Furthermore, the bit interval \(T_{0}\) under the OOK modulation scheme and \(\
u\) is denoted the light speed. The instantaneous electrical SNR according to [14] could be defined as \(\gamma=R^{2}\eta^{2}|I|^{2}/\sigma^{2}\). Meanwhile, the average SNR (\(\mu\)) is stated as \(\mu=(R\eta\,\mathbb{E}\,|I|)^{2}/\,\mathbb{E}(\sigma)^{2}\). Taking for the normalization of \(I\) as \(\mathbb{E}[I]=1\), then, the average SNR could be written as \(\mu=\gamma\,/\,I^{2}\).  
In this work, the VLC link is impaired by the turbulence phenomena in two independent water channel mediums. It is also considered, the optical irradiance beams \(I\) is impaired by attenuation coefficient \(I_{l}\), which is deterministic in nature and depends on the extinction coefficient along with the distance between communication nodes. The extinction coefficient c(\(\lambda\)) is the sum of total absorption coefficient \(\alpha_{NB}(\lambda)\) and scattering coefficient \(\beta_{NB}(\lambda)\). The typical values of \(\alpha_{NB}(\lambda)\), \(\beta_{NB}(\lambda)\) and c(\(\lambda\)) are mentioned in Table 5 [20]. On the other hand, the atmospheric turbulence random variable affects the optical beam which is denoted by \(I_{t}\). The combined normalized attenuation channel fading coefficient for the VLC link is formulated as \(I=I_{l}I_{l}\).
# Fast Flow Reconstruction via Robust Invertible \(n\times n\) Convolution  
[PERSON]  
1 Computer Vision and Image Understanding Lab, Department of Computer Science and Computer Engineering, University of Arkansas, Fayetteville, AR 72501, USA; [EMAIL_ADDRESS] (N.L.); [EMAIL_ADDRESS] (K.L.)1 Computer Vision and Image Understanding Lab, Department of Computer Science and Computer Engineering, University of Arkansas, Fayetteville, AR 72501, USA; thile@uark.  
limited in flexibility. To overcome this limitation, coupling layers are alternated with less complex transformations that manipulate on all dimensions of the data. In RealNVP [32], the authors use a fixed channel permutation using fixed checkerboard and channel-wise masks. [PERSON] et al. [29] simplifies the architecture by replacing the reverse permutation operation on the channel ordering with invertible \(1\times 1\) convolutions.  
However, the \(1\times 1\) convolutions are not flexible enough in these scenarios. It is extremely hard to compute the inverse form of the standard \(n\times n\) convolutions, and this step usually produces high computational costs. There are prior approaches that design the invertible \(n\times n\) convolutions by using emerging convolution [35], periodic convolutions [35], autoregressive flow [36] or stochastic approximation [37; 38; 39]. In this paper, we propose an approach to generalize an invertible \(1\times 1\) convolution to a more general form of \(n\times n\) convolution. Firstly, we reformulate the standard convolution layer by shifting the inputs instead of the kernels. Then, we propose an invertible shift function that is a tractable form of Jacobian determinant. Through the experiments on CIFAR-10 [40], ImageNet [41] and Celeb-HQ [42] datasets, we prove that our proposals are significant and efficient for high-dimensional data. Figure 1 illustrates the advantages of our approach with high-resolution synthesized images.  
**Contributions:** This work generalizes the invertible \(1\times 1\) convolution to an invertible \(n\times n\) convolution by reformulating the convolution layer using our proposed invertible shift function. Our contributions can be summarized as follows:  
* Firstly, by analyzing the standard convolution layer, we reformulate its equation into a form such that, rather than shifting the kernels during the convolution process, shifting the input provides equivalent results.
* Secondly, we propose a novel invertible shift function that mathematically helps to reduce the computational cost of the standard convolution while keeping the range of the receptive fields. The determinant of the Jacobian matrix produced by this shift function can be computed efficiently.
* Thirdly, evaluations of several datasets on both objects and faces have shown the generalization of the proposed \(n\times n\) convolution using our proposed novel invertible shift function.
## 4 Results and Discussion
### Skin Friction Coefficient and the Nusselt Number
The results obtained are compared to existing solutions when there is no magnetic field and the fluid is taken as water only. An excellent agreement between the solutions is seen, as given in Tables 2 and 3.  
methods, namely VIM and RK-F. A comparison with existing solutions is also given to check the accuracy of our obtained results. The effects of the parameters on the skin friction coefficient and heat transfer at the wall are also plotted. The major outcomes of this study are as follows:  
* Angle opening and the Reynolds number have opposite effects on the velocity profile for convergent and divergent channels. * Stretching walls may result in backflow regimes for divergent channels, because this moves the particles near the wall away. An increase in the angle opening and Reynolds number may result in backflow and, thus, separation. This result might cause instabilities in the flow. * The Hartmann number gives a solution to the backflow regions. An increase in the Hartmann number removes the backflow for stretching divergent channels. This effect can be useful in several physical phenomena. * The nanoparticle volume fraction reduces the velocity of the fluid for both copper and silver nanoparticles in the case of a divergent channel. For a convergent channel, the increase in the volume fraction increases the velocity. * Stretching of the divergent channel increases the flow near the walls of the channel. Additionally, shrinking reduces the velocity of the fluid near the walls of the channel. Identical behavior is seen for the case of a convergent channel. * The almost identical behavior of the temperature profile for increasing channel opening is observed for both convergent and divergent channels, both for stretching and shrinking channels. * Temperature is seen to be decreasing for increasing values of the nanoparticle volume fraction. Both stretching and shrinking channels have an almost identical behavior. * Stretching of the walls results in lower temperature values for both convergent and divergent channels. Increasing values of temperature near the walls of the channel are observed for the shrinking case. * The Eckert number increases the temperature of the fluid for all of the cases. * The nanoparticle volume fraction reduces the skin friction coefficient for all of the cases. Stretching channels have lower skin friction values than shrinking channels. * The opposite behavior of the skin friction coefficient for increasing Re is observed for convergent and divergent channels. * The rate of heat transfer at the wall increases with a higher nanoparticle volume fraction and Eckert number. These two parameters have the same behavior for all of the cases.
# Cluster-Based Approaches toward Developing a Customer
## 4 Results
### Application of k-Means  
In this subsection, the data were first normalized using min-max normalization, as suggested by [PERSON] and [PERSON] [26]. The number of clusters was not fixed with the aim of evaluating them, which means that the number of clusters was determined automatically based on the result of the silhouette coefficient.  
The cluster results were derived from the k-means algorithm applied to variables generated from the managers' questionnaire responses, as shown in Table 7. The k-means application facilitates the identification of customer groups with similar behaviors. According to [PERSON] et al. [27], the choice of distance metric between points is a critical decision for achieving high-quality clustering results in this technique.  
This study employed the Euclidean distance metric. The number of clusters, K, was selected based on the results obtained through the silhouette coefficient combined with business experience. The result of the silhouette coefficient is shown in Figure 3.  
According to the result shown in Figure 3, the optimal number of K is 4, corresponding to a result of 0.757 for its silhouette coefficient. In addition to finding the optimal value of K, the current study also aimed to propose new clusters that can be managed more efficiently by the business. Table 8 presents the silhouette coefficient results for the largest K found.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**K Value** & **Silhouette Coefficient** \\ \hline
3 & 0.676 \\
4 & 0.757 \\
5 & 0.684 \\
6 & 0.655 \\ \hline \hline \end{tabular}
\end{table}
Table 8: Silhouette coefficient values for the 4 largest k values found (source: the authors).  
Figure 3: Result of the silhouette coefficient obtained through the implementation of k-means clustering (source: the authors).  
Also, the highest average scores of the silhouette coefficient were found for higher K values, such as K = 5 and K = 6. Although K = 3 showed a high value in the result of its silhouette coefficient, it divides into only three groups. As the objective of k-means clustering is also to propose scenarios of more valuable customer clusters which are manageable by the business, dividing the total customer base into only three groups can make this task more difficult. Therefore, K = 3 was not described and proposed to the business team.  
Figure 4 presents the distribution of the cluster results found for each K. As previously mentioned and corroborated with the result shown in the same figure, K = 3 has good clustering, but it will not be relevant to the business. The same happens with K = 4, K = 5, and K = 6, for which their clusters are well divided and defined within each of their groups.
# Exploring Prior Knowledge from Human Mobility Patterns for POI Recommendation
## 5 Conclusions  
At present, the existing research work on POI recommendation algorithms focuses on the mining of the interaction history between users and POIs and the research on users' social relations, ignoring the urban scene where POI recommendation is located and the objective existence of the prior knowledge of human mobility patterns. To this end, this  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Model Algorithm** & **ACC** & **AUC (ROC)** & **AUC (PR)** \\ \hline
**HMRec** & 0.8103 & 0.7331 & 0.3558 \\
**Wide\&Deep** & 0.7978 & 0.7271 & 0.3499 \\
**DeepFM** & 0.8095 & 0.7253 & 0.3610 \\
**NeuralCF** & 0.7810 & 0.7078 & 0.3097 \\
**Twin Towers** & 0.6922 & 0.6097 & 0.1781 \\
**EmbeddingMLP** & 0.7966 & 0.7103 & 0.3302 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Comparison of experimental results of the POI recommendation model.  
Figure 3: ROC and PR curve visualization of experimental results of recommendation algorithms. The left figure depicts draws the ROC curve of each model. The right figure depicts the PR curve of each model.  
paper proposes a human mobility pattern extraction framework, HMPE, and designs an end-to-end pre-training process using graph neural networks and attention mechanisms. This paper proposes the HMRec POI recommendation algorithm to incorporate prior knowledge of human mobility patterns into POI recommendation. Experiments verify the effectiveness of human mobility patterns in POI recommendation.  
In the future, we will attempt to mitigate the issue of data sparsity by employing data imputation techniques, and we will explore the design of multiple related downstream tasks to simultaneously obtain spatio-temporal prior knowledge from multiple tasks, aiming to comprehensively improve the effectiveness of POI recommendation.  
Conceptualization and methodology, J.S.; data curation and formal analysis, J.S. and Q.Y.; experiments and analysis, J.S., Q.Y., H.G. and B.W.; investigation, H.G.; validation and visualization, Q.Y., H.G. and B.W.; writing--original draft preparation, J.S., Q.Y. and H.G.; writing--review and editing, X.K. and Q.Y.; resources and supervision, X.K.; funding acquisition, X.K. and B.W. All authors have read and agreed to the published version of the manuscript.  
This research was partially supported by the National Natural Science Foundation of China (62072409), Zhejiang Provincial Natural Science Foundation (LR21F020003), Program, for improving the Scientific Research Ability of Youth Teachers of Inner Mongolia Agricultural University (RZ2200001860) and Major Science and Technology Projects of Inner Mongolia Autonomous Region (2020 ZD0004).  
Not applicable.  
The authors declare no conflict of interest.
# A Distributed Autonomous Mission Planning Method for the Low-Orbit Imaging Constellation
## 2 Problem Description
### Notations  
\(S=\left\{s_{1},\ s_{2},...,\ s_{|S|}\right\}\), the set of satellites, \(|S|\) represents the number of satellites. \(M_{i}\) represents the maximum storage capacity of satellite \(s_{i}\) during the planning period.  
Figure 3: Communication topology of the Walker-\(\delta\) (20/2/1, 600 km, 60\({}^{\circ}\)) constellation.  
Figure 2: Walker-\(\delta\) (30/3/1, 600 km, 60\({}^{\circ}\)) constellation [21]. (**a**) Three-dimensional graph of satellite constellations; (**b**) communication topology among satellites, a line indicates that an inter-satellite link can be established between two satellites for communication.  
\(T=\left\{t_{1},\,t_{2},...t_{|T|}\right\}\), the set of missions, \(|T|\) denotes the number of missions. \(m_{j}\) denotes the estimated consumption of storage for the execution of task \(t_{j}\). \(d_{j}\) is the required observing duration of task \(t_{j}\). \(t_{sj}\) denotes the start time of the execution of task \(t_{j}\), \(te_{j}\) denotes the end time of the execution of task \(t_{j}\). \(tr_{jj}\) represents the required attitude transition time for the satellite to perform two adjacent tasks between \(t_{j}\) and \(t_{j}\). \(p_{j}\) denotes the priority of the task \(t_{j}\). \(r_{j}\) represents the benefit of task \(t_{j}\). Considering the urgency and timeliness of observing tasks, this article introduces a mechanism for task benefits to decay over time. On the basis of the priority \(p_{j}\), the benefit \(r_{j}\) decays with the delay of its execution start time \(ts_{j}\). The calculation formula is shown in Equation (1), \(\lambda\) is the attenuation factor.  
\[r_{j}=p_{j}e^{-\lambda ts_{j}}, \tag{1}\]  
\(W_{ij}=\left\{w_{ij1},\,w_{ij2},\,\ldots,\,w_{ij|W_{ij}|}\right\}\), the set of O-VTWs of satellite \(s_{i}\) for task \(t_{j}\), \(|W_{ij}|\) denotes the total number of O-VTWs of satellite \(s_{i}\) for task \(t_{j}\). \(w_{ijk}\) denotes the kth O-VTW of satellite \(s_{i}\) for task \(t_{j}\). \(ws_{ijk}\) indicates the start time of \(w_{ijk}\), \(ue_{ijk}\) indicates the end time of \(w_{ijk}\).  
\(x_{ijk}\), decision variable. \(x_{ijk}=1\) if task \(t_{j}\) is executed in \(w_{ijk}\), \(x_{ijk}=0\) otherwise.
# A Novel Optimization Framework to Replicate the Vibro-Acoustics Response of an Aircraft Fuselage
## 3 CAD/FEM Modeling
### Boundary Conditions  
Apart from the previously described boundary conditions, all the remaining settings were corresponding for both RC and SCs. In particular, a fully clamped condition (Figure 8a) was imposed at the two ends of the barrel (no translations neither rotations were allowed for such nodes). The two fuselage ending surfaces were considered as acoustically fully reflecting, thus assuming that no interaction between internal and external fluids was allowed. Moreover, the six faces of the cube volume, representative of the external fluid, were modeled as anechoic walls, thus assuming that no reflection was allowed (Acoustically Matched Layer; Figure 8b) [9]. Finally, a strong coupling condition between fluids and structural nodes was set up to allow for a bidirectional interaction between structure and surrounding fluid [9].  
Figure 8: Boundary conditions: (**a**) clamped structural nodes, (**b**) non-reflecting boundary conditions.  
Figure 7: Simulated Cases overview: (**a**) Simplified Case \(1\) (SC1), (**b**) SC2; red dots representing the monopoles and dotted black lines representing the rings along which microphones are positioned.  
Initial sound power amplitudes and phases were assigned for each monopole source and, step-by-step, adjusted by the optimization procedure.  
At this stage, the goal of the work was not an accurate reproduction of the real fuselage response to the sound pressure coming from the engines, but only the implementation and validation by comparison between RC and SCs of a general MDO procedure to solve a complex optimization problem such as the one here proposed. It is worth noting that the MDO procedure here proposed required many FEM solutions of the current model to provide a stable solution; therefore, some simplifications were considered as a trade-off between a sufficiently accurate physical replication of the vibro-acoustic fuselage behavior and an acceptable computational burden.  
A comparison between the cross sections of the so created FEM models built up for RC and SC is shown in Figure 9.
## 7 Conclusions and Future Development Paths  
The hybrid MTS-MTO models can reduce the inventory costs of the MTS while maintaining similar levels of other performance measures, such as tardiness, average time in the system, and stability of the average time in the system. Most hybrid models proposed are characterized by the determination of a static decoupling point or rely on mathematical models that may limit their application in more complex real-world industrial settings. The research presented in this paper proposes a dynamic decoupling point that adapts to changing conditions. The proposed models are characterized by lower computational complexity, allowing their implementation in more complex manufacturing systems.  
Simulation models were developed to test the proposed models under various conditions, comparing the results with pure MTO and MTS systems. The numerical results highlighted that the proposed models can effectively reduce inventory costs (WIP) with minimal performance reduction compared to the MTS system. Specifically, the periodic review approach performed better, while the continuous review, despite being more complex, did not offer significant additional benefits. The proposed models performed better in conditions of higher manufacturing system congestion (lower inter-arrival parameter).  
The managerial implications of this research provide decision-makers with support in selecting the optimal dynamic policy that balances the reduction of work in process with the potential degradation of manufacturing performance. This balance depends on the cost evaluation of the specific industrial case.  
Future research extensions could include considering multi-product customer demand and evaluating batch sizes of customer orders. Additionally, further studies could investigate the costs associated with the degradation of manufacturing performance and inventory level costs.  
This research received no external funding.  
Not applicable.  
The raw data supporting the conclusions of this article will be made available by the authors on request.  
The author declares no conflicts of interest.