esa-sceva/satcom-chunk-collection huggingface dataset:
# Boating Tourism and Fishing Interactions: A Social Network Analysis Using AIS Data
## 5 Discussion
### Temporal Patterns  
The AIS data show that the patterns of recreational tourist activities occur during the day. There is greater incidence in the warmer seasons or when the holiday periods (e.g., Christmas and Easter) receive a greater abundance of visitors who are predisposed to participate in these types of activities.  
In the case of fishing, although there are fewer records in the winter months, the activity, regardless of the type of fishing gear, extends throughout the year. The limitations of the activity are limited to storm days when the inlets are closed or when certain fishing quotas have already been reached (essentially purse-seine vessels). There are still limitations if boats go to the shipyard for annual maintenance or repairs [59]. This type of break usually occurs in the months of December and January. Several records that corresponded to this type of situation were found. For this purpose, it was considered that the boats were in dry dock.  
In winter, there is apparently no potential conflict due to the lower activity of recreational boats. As can be seen from the Sankey diagrams (Figure 4), there is a slight prevalence of more records of recreational boats in the summer, but this is reversed for the winter season, where records related to fishing activities prevail. In the summer, the potential conflict increases slightly, and it may only be in the intermediate coastal areas where there may be some overlap in the areas of interest to exploit resources.  
All other activities are related to vessels that do not interact with each other if it is considered the same time period. However, it is important to note that AIS data have limitations and that it is not possible to infer what actually happens, but only what can be discerned from the processed data [60].
## 2 The Proposed RDHEI Method
### Room Reservation and Image Encryption
#### 2.1.2 The Quadtree Decomposition  
Quadtree is a hierarchical data structure that recursively subdivides an image into square blocks until a certain condition is met. Quadtree partitioning is widely used in various applications, including image processing, computer graphics, and computational geometry. Figure 7a,c demonstrate the MSBs of the mapped prediction errors for the Lena and Jetplane images, respectively. The significant bit planes exhibit multiple uniform regions. This can serve as an effective way to provide room for data hiding. Rather than dividing each bit plane into non-overlapping blocks of equal size (usually \(4\times 4\)) [8], we suggest employing quadtree decomposition to generate large, uniform blocks with minimal auxiliary information.  
Figure 8 shows the MSBs of the mapped prediction errors for the Lena and Jetplane images, and their corresponding quadtree decompositions. As observed from Figure 8b,d, extremely larger uniform blocks are found. A binary string is then used to represent the quadtree decomposition of each bit plane. Additional bit planes and their corresponding quadtree decompositions are shown in Figure 7.  
In the conventional implementation of the quadtree decomposition, an image is recursively divided into smaller sub-blocks until each block becomes homogeneous, indicating that all pixels in the block have the same intensity value, or until the size of the sub-blocks becomes less than a defined limit (\(2\times 2\) in our case). The quadtree decomposition can be seen as a depth-first traversal (DFS) of a tree structure, where it starts from the root node (i.e., the whole image) and recursively visits its child nodes until it reaches the leaf nodes (i.e., homogeneous sub-blocks, or sub-blocks with size \(2\times 2\)), meaning that it visits all child nodes of a parent node before moving to its siblings.  
The conventional implementation of the quadtree decomposition does not meet well with the requirements of our room reservation method. When using the quadtree decomposition based on the DFS approach, the algorithm tends to traverse very small, homogeneous, and non-homogeneous blocks first. However, reordering the homogenous blocks into the beginning of each embeddable bit plane is needed, and we propose a new implementation that prioritizes the traversal of the largest homogeneous blocks first. This allows us to gradually reorder each bit plane as the quadtree decomposition continues processing it. Algorithm 2 details the proposed quadtree decomposition method. For each embeddable bit plane, the algorithm outputs the binary string, corresponding to its quadtree decomposition, and the list of homogeneous blocks that will be used in the data hiding process.
## 2 Theory
### Smooth Inversion of Gravity Data Based on Conjugate Gradient Algorithm
Data fitting function and model constraint function are defined as:  
\[\phi_{d}=\|Sm-d\|^{2} \tag{7}\]  
\[\phi_{m}=\|m\|^{2} \tag{8}\]  
The data weighting matrix, \(W_{d}\) and the model weighting matrix, \(W_{m}\), used in this paper are diagonal square matrices, with the diagonal element defined as [26]:  
\[diag(W_{d})=diag\Big{(}SS^{T}\Big{)}^{\frac{1}{2}} \tag{9}\]  
\[diag(W_{m})=diag\Big{(}S^{T}S\Big{)}^{\frac{1}{2}} \tag{10}\]  
After incorporating the data weighting matrix and the model weighting matrix, Equation (6) can be re-expressed as:  
\[\phi=\|W_{d}(Sm-d)\|^{2}+\alpha\|W_{m}m\|^{2} \tag{11}\]We can solve the problem in Equation (11) using the reweighting algorithm proposed by [PERSON] [7], as described in the following formulas:  
\[\phi=\frac{1}{2}\times(\left\|S_{w}m_{w}-d_{w}\right\|^{2}+\alpha\left\|W_{m}^{- 1}m_{w}\right\|^{2}) \tag{12}\]  
\[d_{w}=W_{d}d \tag{13}\]  
\[m_{w}=W_{m}m \tag{14}\]  
\[\phi=\phi_{d}+\alpha\phi_{m} \tag{6}\]0  
In this paper, the conjugate gradient algorithm is used to find the optimal solution \(m_{w}\), which minimizes the objective function in (12). The iterative process of the conjugate gradient algorithm requires the calculation of the first derivative of the objective function \(\phi\) with respect to the weighted density parameter \(m_{w}\), and the formula for calculating the first derivative is given as follows:  
\[\phi=\phi_{d}+\alpha\phi_{m} \tag{6}\]1  
An adaptive method [7] is selected to select regularization parameters, where the convergence of the inversion results gradually decreases the contribution value of the model constraint function and the value of \(\alpha\) is selected through iteration is:  
\[\phi=\phi_{d}+\alpha\phi_{m} \tag{6}\]2  
In the next iteration, the decay value of \(\alpha\) is determined by Equation (18):  
\[\phi=\phi_{d}+\alpha\phi_{m} \tag{6}\]3  
Additionally, constrains on the upper and lower limits of the density parameter have been added to control the inversion results within a reasonable range, as expressed in the following formula:  
\[\phi=\phi_{d}+\alpha\phi_{m} \tag{6}\]4  
Based on the above considerations, the gravity data inversion algorithm based on the traditional conjugate gradient algorithm is presented as follows.
###### Abstract  
The cooling effect of turbine vane is of great importance for ensuring thermal protection and economic operation of gas turbines. This study aims to reveal the influence mechanism and performance of impingement cooling and heat transfer within a turbine guide vane cavity. Then, a turbine guide vane cavity with a complex pin fins structure is numerically investigated at a multi-hole impingement by comparison with experiment verification. The results show that the larger the Reynolds number is, the larger the average Nusselt number is on the upper and lower surfaces of the cavity. The average Nusselt number increased on the upper and lower surfaces as the impingement hole diameter increased. Comparing 1 impingement hole with 16 ones, the average Nusselt number of the lower surface of the latter is 553.9% larger than that of the former. Furthermore, the average Nusselt number of the lower surface for pin height of 3 mm is only improved by 11.2% for pin fin height of 24 mm. The heat transfer effect near the impingement holes is better than that far away from the impingement holes. In particular, it is recommended to have 14 impingement holes with a hole diameter of 7.2 mm, as well as circular pin fins with a height of 3 mm and spacing of 25.8 mm. In addition, the entropy generation distribution in impingement cooling is analyzed. This study can provide a reference to enhance the turbine vane cooling performance by optimization design.  
turbine vane cavity; impingement cooling; pin fin; multi-hole; heat transfer +
Footnote †: journal: Applied Sciences
# Improving IMES Localization Accuracy by Integrating Dead Reckoning Information
## 7 Experiment of the Interference of the Human Body
### Discussion  
In consideration of the experimental results mentioned above, it is clear that the human body influences the CNR. Unless its influence can be mitigated, IMEs trilateration cannot perform well. One possible solution is to model the influence of the human body and use it to correct the acquired CNR. However, there is a chicken-and-egg problem here; that is, the correct position and orientation of a pedestrian need to be known to correct the body-influenced CNR, but the corrected CNR is necessary to estimate proper position and orientation. In order to overcome this problem, an accurate human body model and a well-performed PDR system would be necessary.
# Junction Temperature Optical Sensing Techniques for Power Switching Semiconductors: A Review
## 4 Method of Calibration
### IRC Sensing Technique  
The calibration setup for thermal imaging consists of a lens with a predetermined working distance to focus the thermal radiation on the camera's detector [37]. In the literature, the reported distance is between 15 and 25 cm. An adjustable emissivity setting is required to calibrate the detection based on the orientation of the targeted object and ambient conditions for each setup.  
As illustrated earlier in Figure 5, the infrared thermal imager should be positioned at a distance and to the front of the IGBT, as a direct line of sight is required; the focal length is firstly set, after which the camera is fixed with a gripper once the infrared thermal imager is correctly displayed on the screen [111]. For commercial IGBT, the dielectric gel on the chip surface may be removed and painted for uniform emissivity across the chip surface for accurate measurements. Also, the paint may be filtered to attain a uniform particle size whose thickness ranges from 5 to 16 \(\upmu\)m, as suggested in [70], to improve the accuracy.
# River Discharge and Saltwater Intrusion Level Study of Yangtze River Estuary, China
## 4 Discussion  
### Salinity Levels in the North Branch (NB) and South Branch (SB)  
The NB is crucial for the saltwater intrusions into the YRE. The high salinity not only affects the freshwater usage on Chongming Island along the NB of Jiangsu Province, but also affects the water withdrawn of the SB (Dongfeng Xisha Reservoir). During the dry seasons, the salinity of the NB still remains above 20% even though the tide levels are low [30; 31]. However, the data were found to be lacking regarding these limits. In addition, strong salt intrusions may also occur during the flood seasons. From 18 to 19 September of 2001, the freshwater discharges from the Yangtze River were observed to be high (38,000 m\({}^{3}\)/s) at Datong station. However, the saltwater intrusions into the NB remained strong, and were even recorded to have affected the water intake levels on the southern coast of Shanghai at the Chenhang Reservoir [32]. This situation had never occurred before. The saltwater intrusions had two ways into the SB. One way was affected by the sea tides, and the other was the result of spill-over conditions. The salinity levels in the SB were distributed from upstream to downstream as \"high-low-high\". The \"high\" point was located at the north and south junction at Chongming Island, and the \"low\" point was located near the central Wusongkou. The excess salinity areas (salinity \(>\) 0.45%) were in the upper reaches of the SB, in which the downstream part of the area continuously increased and expanded toward the middle reach area (Figures 9 and 10).
# Implementing and Testing a U-Space System: Lessons Learnt
## 3 The U-Space Services
### Conflict Management
One particular tactical deconfiction situation appears when the operator needs to abort and change the current flight plan. This capability was fundamental for missions like those of the first responders, who must adapt their support to the development of the events. In those situations, the chosen procedure was the following. First, the pilot requested a cancellation of the current flight. The UAV should then be kept hovering until the end of the procedure. Automatically after the cancellation request, a safety dynamic geo-fence was created around the UAV and any traffic affected was deviated. In the case of fixed-wings, the geo-fence size was tailored to give room to the holding loop pattern required by the aircraft. Pilots could then design and submit the new plan. After a successful approval process (i.e., no conflicts found), and before starting to execute it, they had to send a start-of-flight message. When doing it, the geo-fence was removed and they could start the new plan. With little practice, the aircrew became used to this procedure and executed it rapidly. If they forgot to send the start-of-flight message, they received a warning when the safety geo-cage was left, so they could immediately solve it. A similar procedure was provided for those cases wherein the need was to stop and fly manually in the area without a predefined trajectory. Here, after canceling the ongoing plan, operators would ask for a geo-cage, broadcast as a new geo-fence to the rest of the traffic. When the area was segregated (other drones of the same operator were allowed), the operator could start flying freely inside it; within it, the separation was a responsibility of the pilot.
## 7 Conclusions
The small-scale fading distribution mean value in the range of [\(-\)0.4; \(-\)0.2], standard deviation in [1.5; 2.2] for NB channel and, respectively, [\(-\)0.3; \(-\)0.2] and [0.7; 1.7] for UWB channel, should be considered for radio link designing. A statistical analysis of the model parameters was also carried out and its good fit to the empirical data was demonstrated. Future work will focus on determining the system loss model dependency on frequency. The behavior of channel impulse response, especially in the UWB channel, in accordance to the MN placement on the human body will be investigated. All authors contributed to developing the measurement equipment, designing and performing measurements, data analysis, scientific discussions, and writing the paper. This work was developed within framework of the COST Action CA15104 \"Inclusive Radio Communication Networks for 5G and beyond\" (IRACON) and with financial support of the Faculty of Electronics, Telecommunications and Informatics of Gdansk University of Technology. The authors declare no conflict of interest.
# Matheuristics for the Design of a Multi-Step, Multi-Product Supply Chain with Multimodal Transport
## 4 MILP Model and Matheuristics
### Mixed-Integer Linear Programming Model (MILP)
#### 4.1.2 Objective Function  
The objective function (1) is to minimize the sum of all the costs that we are taking into account in the model. The first term adds the fixed costs of opening a factory, the second, the fixed costs of opening a warehouse, the third the purchase and transportation costs from the supplier to the factories of the materials, the fourth, the cost of manufacturing and transportation from the factories to the warehouses and the fifth the transportation from the warehouses to the customers.  
\[Min\sum_{f\in F}\sum_{q\in Q}Fc_{fq}z_{fq}+\sum_{w\in W}\sum_{q\in Q }Fc_{wq}z_{wq}+\sum_{r\in R}\sum_{s\in S^{r}}\sum_{f\in F}\sum_{t\in T_{sf}}( PC^{r}_{s}+TC^{rt}_{sf})x^{rt}_{sf}+\] \[\sum_{p\in P}\sum_{f\in F^{p}}\sum_{w\in W^{p}}\sum_{t\in T_{sf}} (MC^{p}_{f}+TC^{pt}_{fw})x^{pt}_{fw}+ \tag{1}\] \[\sum_{p\in P}\sum_{c\in C^{r}}\sum_{w\in W^{p}}\sum_{t\in T_{wc} }DEM^{p}_{c}TC^{pt}_{wc}u^{t}_{wc}\]
## 4 Experimental Settings and Results
### Evaluation Methodology  
Accuracy and correctness are the two standard metrics used by researchers to evaluate the effectiveness of the proposed approach. Accuracy (Equation (1)) is a measure indicating correctly recognized words. A word is considered correct if all its characters are true. If one of the characters of a word is wrong, it is considered a wrong word. There are three types of wrong words: wrongly inserted words that are not in the real dataset, deleted words which are in the real dataset but are deleted wrongly, sub-words which are substitutions of the true word. Punctuations like \"\(\alpha\)\" or \"?\" are considered as a single character.  
Correctness (Equation (2)) also indicates correctly recognized words but it does not consider inserted words.  
\[Accuracy=\frac{\#AllWrds-(\#InsWrd+\#DelWrd+\#SubWrd)}{\#AllWrd}*100\,. \tag{1}\]  
\[Correctness=\frac{\#AllWrds-(\#DelWrd+\#SubWrd)}{\#AllWrd}*100\,. \tag{2}\]  
In Equations (1) and (2), \(AllWrds\) is the number of all words in the text, \(InsWrd\) is the number of wrongly added words to the text. \(DelWrd\) is the number of wrongly deleted words from the text, and \(SubWrd\) is the number of wrongly replaced words in the text. We have used (Equation (1)) for accuracy of character recognition, while characters are considered instead of words.
## 4 Results
### Hydrodynamic Response
#### 4.1.2 Static Response  
The maximum hydrodynamic forces in the transverse and vertical directions calculated from Equation (6) or (7) were applied as equivalent static nodal forces in the static analysis. The intensities of these forces in the transverse (\(\gamma\)) and vertical (\(Z\)) directions were 4.875 kN/m and 4.858 kN/m, respectively. The static analysis of the SFT is useful for assessing the performance of the SFT for the preliminary design.  
Static displacements and internal forces envelope curves of the SFT are shown in Figure 5. The transverse response of the SFT, i.e., rotations (\(\theta_{Z}\)), displacements (\(q_{Y}\)), bending moments (M\({}_{Z}\)) and shear forces (SF\({}_{Y}\)) decreased when the mooring cable configuration was changed from C1 to C3. However, the vertical response, i.e., the rotations (\(\theta_{Y}\)), displacements (\(q_{Z}\)), bending moments (M\({}_{Y}\)) and shear forces (SF\({}_{Z}\)), have different trends, where the response for configuration C2 is the greatest, followed by configuration C3, and configuration C1 has the minimum response. Comparisons of static displacements and internal forces of the SFT for three mooring configurations at Sections A, B and C (Figure 2a) are summarized in Table 3 to clearly show the trends described above.  
The shape of bending moment gives direct insight into the cable configurations and performances of mooring systems and reflects the uniqueness of the adopted mooring cable configurations, as can be seen in Figure 5c. From these results, it can be concluded that the static response provides an important benchmark for decision-making regarding mooring cable arrangements and configuration selection for the preliminary design of SFT. However, the static response is very small and could not be used for the practical design of SFT, as shown in Figure 4, as will be demonstrated further in the following sections.  
Figure 4: Comparison of absolute displacements with ABAQUS/Aqua [8]: (a) absolute static displacement and (b) absolute dynamic displacement.  
Figure 5: _Cont._
## 4 Results
### Cyclist Mobility  
In the RMSC, there is much room for improvement in cycling infrastructure. In urban areas, in the great majority of municipalities there is no infrastructure, and cyclists have to share the road with other vehicles. The graph (Figure 13) shows the analyses of the frequency of cycling and the motivation for its use in the RMSC. It can be clearly seen that the rates are negative, as there is hardly any use of this means of transport. A total of 54% of users do not use bicycles; those who use them occasionally account for 25% of those surveyed, and only 6% of those surveyed use this means of transport on a daily basis.  
The citizens surveyed who use bicycles occasionally, several times a month or daily, the frequent users of bicycles, use this means of transport for sport and not for work or educational purposes, accounting for about 70% of the population surveyed.  
In the figure above, we can see how citizens rate the facilities for cycling in their municipalities. In general terms, the assessment of cycling is relatively positive, with 59% of those surveyed considering it to be excellent (6%), good (20%) or acceptable (33%). However, a high percentage of those surveyed considered that there were no facilities available for cycling as a means of transport, with 41% of those surveyed describing them as deficient or very deficient in their municipalities. As shown in the graph above, the main problem faced by the RMSC's inhabitants when using bicycles was the fear of sharing public space with motor vehicle traffic, accounting for 35% of the responses. Other problems reported by respondents to the survey include the excessive physical effort required (29%) and the longer journey time (13%). Other problematic factors to be taken into account are the unfavourable climate (13%) and the unavailability of adequate and safe parking areas at the destination (10%).  
Figure 13: Cycling mobility situation in the RMSC. (**a**) Cycling frequency; (**b**) Reasons for cycling; (**c**) Cycling facilities; (**d**) Cycling difficulties.  
Surveys were carried out to obtain citizens' evaluations of the situation of cycling mobility infrastructure, but also to determine how well citizens accept the improvement and incorporation in their municipalities of infrastructure that promotes the use of this means of transport. Figure 14 shows the level of acceptance of two proposals that could improve cycling mobility in these municipalities: on the one hand, the creation of bicycle rental stations, and on the other, the construction of urban and inter-urban cycle lanes.  
The evaluation of the survey proposals was very positive, with 62% of respondents agreeing or strongly agreeing with the installation of bicycle rental points and 73% agreeing with the creation of bicycle lanes. On the other hand, 8% of respondents disagreed or strongly disagreed with the creation of bicycle rental points and 10% on the issue of bicycle lanes; however, this figure is not very representative.
# Evolution of V2X Communication and Integration of Blockchain for Security Enhancements
## 5 Issues and Challenges in 5G and Edge-Based V2X
### Data Integrity  
In vehicular networks, data integrity is a critical issue and inconsiderate verification generates biased data integrity outcomes. In the cloud or at the edge, 5G data storage and analysis creates concerns regarding data integrity. The data outsourced and stored on the edge server gives rise to concerns related to data breaches, data modifications, deletion, or misuse without the user's knowledge. A careful and periodical data verification is required to protect the data integrity from malicious vehicles.