esa-sceva/satcom-chunk-collection huggingface dataset:
# New Compact Wearable Metamaterials Circular Patch Antennas for IoT, Medical and 5G Applications
## 2 Compact Circular Microstrip Antenna with Split Ring Resonators  
A circular microstrip antenna with CSRRs is presented in this section. The antenna is printed on dielectric substrate with dielectric constant of 2.2, loss tangent of 0.002 and 1.6 mm thick. The radiating element consist of a circular patch with eighteen CSRRs, the maximum number of CSRR that can be inserted in the radiator area. The CSRRs improve the antenna effective area. The diameter of the circular antenna with CSRR, shown in Figure 2a, is 36 mm. The antenna center frequency is 2.6 GHz.  
Figure 1: Progress in development of small antennas. (**a**) Small Antennas Gain; (**b**) Small Antennas bandwidth.  
The resonant frequency of the dominant mode TM11 of the circular microstrip antenna is given by Equation (1), see [1], where c is the light velocity in vacuum. Where \(a_{e}\) is the radius of the circular microstrip antenna and it can be calculated by using Equation (2), [1]. \(\varepsilon_{e}\) is the effective dielectric constant. At 2.6 GHz the diameter of the circular microstrip antenna should be 46.6 mm. The CSRR outer diameter ring is 5.2 mm, as shown in Figure 2b. The width of the CSRR strip is 0.15 mm. The CSRR dimensions was optimized by using 3D full analysis end commercial electromagnetic software. All the antennas presented in this paper were analyzed by using 3D full wave software, see [41].  
\[f=\frac{1.8412c}{2\pi a_{e}\sqrt{\varepsilon_{e}}} \tag{1}\]  
\[a_{e}=\frac{1.8412c}{2\pi f\sqrt{\varepsilon_{e}}} \tag{2}\]  
The diameter of the circular antenna with CSRR is smaller by 23% than the diameter of the circular antenna without CSRR. The CSRRs design detail was presented in previous publications, see [2; 3; 4; 5; 16]. The CSRRs improve the effective area of the antenna. The maximum number of CSRRs is placed on the circular patch antenna. The circular antenna bandwidth is around 5% for S11 lower than \(-\)9 dB. The antenna bandwidth is around 8% for S11 lower than \(-\)6 dB as presented in Figure 3. The antenna beam width is around 82\({}^{\circ}\). The antenna gain is around 7.6 dBi as presented in Figure 4. The antenna efficiency is around 83%. The gain and directivity of the circular patch antenna with CSRR is higher around to 2.5 dB to 3 dB than the circular patch antenna without CSRR. The antenna bandwidth may be improved by adding a second radiating layer.  
Figure 2: (**a**) Circular microstrip antenna with Circular Split-Ring Resonators (CSRR); (**b**) Photo of a single CSRR.
# HI-Sky: Hash Index-Based Skyline Query Processing
## 1 Introduction
Specifically, we compare the index creation time and skyline query processing time with state-of-the-art skyline query methods including sort-filter skyline (SFS) [16, 17], BBS [6, 7], and Z-SKY [10, 11] in a single system environment. The results of our experiment demonstrate that HI-Sky can generate indices faster than other methods and perform faster skyline query processing at higher dimensions by effectively reducing the number of dominance tests. The remainder of this paper is organized as follows: In Section 2, we discuss existing work related to the proposed method. Section 3 describes the theoretical background of HashGrid and  
Figure 1: An example of skyline query. HI-Sky. Section 4 presents the results of a comparison with existing methods. Section 5 summarizes the conclusions of this study.
## 5 Discussion  
If there is an optimal power allocation scheme, the performance of the proposed scheme would be much better. The proposed scheme is a complicated resource allocation scheme, which consists of D2D underlaying uplink and D2D, and it is managed by units of zone. According to numerical results and simulation results, the transmit power of D2D and cellular link is the most important factor to determine the performance of the proposed scheme. It means that the proposed scheme is sensitive with a power allocation scheme. If an optimal power allocation scheme is adopted on the proposed scheme, it can be better than the case of the static power allocation. Furthermore, the sectorization can be optimized. It can adopt a more higher faction algorithm in a cell if the smart antenna scheme can support it. Depending on the average transmit power for each link, the optimal fraction algorithm can also vary. To optimize the proposed scheme, the fraction algorithm and power allocation for each device should be optimized at the same time. This is future work of the proposed scheme.
# Experimental Study on the Desalination of Waste Leachate Using the Combined Freezing Method
## 3 Results and Discussion
### The Desalination Effect of Different Desalination Methods on Waste Leachate
#### 3.2.3 Research on the Desalination Effect of the FBM on Waste Leachate
With the prolongation of the blowing time, the salt rejection slowly increases, and when the blowing time is 2, 3, 4, and 5 min, respectively, the ice production rate decreases from 56.15% to 25.8%, and a large amount of ice melts to soak and rinse the crushed ice from the top to the bottom, which then achieves a higher rate of salt rejection, which is 24.33% higher, reaching 78.62%, 84.52%, 89.92%, and 93.86%, respectively. At low temperatures, water molecules are arranged in an orderly manner and gradually deposited on the surface of ice crystals [33]. The broken ice will be fused due to the physical properties of solidification and crystallization, and when the fine ice crystals are in contact with each other, they will interact with each other. The deposited water molecules expand to other ice crystals to form broken ice with a larger surface area and more pore space, which results in a more stable rate of salt discharge and a steady increase in salt rejection. Extending the blowing time causes the ice crystals to continuously melt and discharge the concentrated solution carrying salt ions, which increases the quality of the concentrated solution obtained, while the quality of the ice meltwater decreases, reflecting the effluent situation of the leachate wastewater treatment (Figure 11). When blowing for 5 min, the lowest salinity of the ice meltwater is 0.25%, and the salt rejection is 93.86%. The obtained  
Figure 9: Desalination parameters of the FGBM on waste leachate (gravity action for 100 min). concentrated solution and ice meltwater have masses of 767.46 g and 269.63 g, respectively, and the effluent is only 26%. The experimental results indicate that the desalination effect of the FCBM on waste leachate wastewater increases with the increase in the blowing time, which solves the problems of large ice thickness and low salt rejection. However, the increase in the processing time leads to a decrease in the water yield, which is also the reason why the blowing time cannot be set too long.
# A Survey on Optimal Channel Estimation Methods for RIS-Aided Communication Systems
## 2 System Models for RIS-Assisted Systems
### MISO Systems
#### 2.1.1 System Model
On the contrary, \(\widetilde{h_{\text{k},0}}=a_{BS}\left(\varphi^{(BS)}_{k},\psi^{(BS)}_{k} \right)\), where \(\varphi^{(BS)}_{k}\) and \(\psi^{(BS)}_{k}\) are the azimuth and elevation AoD from the BS in the direction of the \(k\)-th UE [74]. Furthermore, there is no spatial correlation among the antennas and the distribution of the non-line-of-sight (NLoS) component of the channels \(\widetilde{h_{\text{k},2}}\), \(\widetilde{h_{\text{k},0}}\) and \(\widetilde{H_{1}}\) are independently and identically distributed complex Gaussian random variables with zero-mean and unit-variance [74]. Finally, the obtained signal for the \(k\)-th UE \(y_{k}\in\mathbb{C}\) is equal to  
\[y_{k}=\sum_{k=1}^{K}\sqrt{P_{k}}h_{\text{k}}^{\text{T}}f_{k}x_{\text{k}}+n_{ \text{k}}, \tag{5}\]  
where \(P_{k}\) denotes the allocated power and \(x_{\text{k}}\) is the signal for \(k\)-th UE, \(f_{k}\) is the beamforming vector for the \(k\)-th UE, \(n_{k}\in\mathbb{C}\) represents a circularly symmetric complex additive Gaussian noise with \(\mathbb{E}\left[n_{k}n_{k}^{H}\right]=\sigma^{2}\)[74].
# Long-Range Multispectral Thermal Imager for Simultaneous Measurement of Distance and Temperature
## 3 Experiments
### Simulation Experiment  
In the simulation experiment, the static images at normal temperature at different distances are measured by the multi-spectral thermal imager. In the measurement process, the long exposure and wide band mode of the multi-spectral thermal imager are used to increase the light input. We shot the tin structure at ten different distances. Ten sets of data cover the measured distance from 50 m to 300 m, and the center of the house is kept in the center of the image during the measurement process. The original image taken is shown in Figure 4a. The distance value calculated by the multispectral thermal imager  
Figure 3: Calibration curve and fitting results of multispectral thermal imager.  
Figure 2: Field experiment. (**a**) Field experiment diagram of multispectral thermal imager. (**b**) Original image taken by multispectral thermal imager.  
is compared with the distance value obtained by the laser rangefinder, and the result is shown in Figure 4b. Because the error of the laser rangefinder can be ignored in the normal temperature and static environment, the measuring accuracy of the multispectral thermal imager is verified as the true value.  
As shown in Figure 4, with the increase in the actual distance, the error also increases gradually. As can be seen from the curve in Figure 3, with the increase in the distance, the offset of the pixel decreases, while there are errors in the image matching of the temperature field at different wavelengths, thus increasing the error of the distance.
# Multi-Authority Revocable Access Control Method Based on CP-ABE in NDN
## 2 Related Works
The first reason is that because of the content caching mechanism of the NDN, even after the content is successfully forwarded, it cannot be reused by other users, and the cached content in the content store in the NDN can be reused. The second reason is that since multiple users may share each attribute, the revocation of any one attribute may have an essential impact on other users in the attribute group. The third reason is that many solutions do not support attribute revocation and flexible user in a multi-authority NDN cache system. Therefore, this paper proposes a multi-authority revocable access control method based on CP-ABE in NDN. This method realizes data access control and user revocation and attribute revocation of rights in NDN cache system through proxy decryption, and can resist collusion attack. Forward security and backward security are also achieved. Compared with single-privileged CP-ABE scheme and multi-authority CP-ABE scheme, the attributes of the multi- authority CP-ABE scheme come from different attribute domains and are authorized by different authorization centers. Therefore, the multi- authority CP-ABE scheme is more appropriate for content access control of the NDN cache system.
## 5 Real World Experiment  
The SO-DRL was well validated in a simulation scenario where the training weights were obtained, and the weights were then deployed in a real air-ground unmanned system with no adjustments. We conducted real UGV and UAV path planning and obstacle avoidance experiments in the real world. Experiments were performed using a customized air-ground unmanned system. This section introduces our platform and validates the SO-DRL on a real hardware system.  
In the real-world experiment, the construction of the hardware for the air-ground unmanned system was completed. The experiments focused on two aspects. On the one hand, the real-world experiments verified the feasibility of SO-DRL to complete obstacle avoidance and reach the destination in the real world. On the other hand, SO-DRL was able to complete the task in the real world without parameter modification, and the end-to-end algorithm could only be implemented in the real world with weights trained on the computer.  
We designed a UGV and a UAV for SO-DRL for the flight experiments (in Figure 12). The UGV (in Figure 12a) was built equipped with McNamee wheels. The UAV (in Figure 12b) consisted of a flight controller Pixhawk V4 on a custom carbon fiber board with a 410 mm diagonal wheelbase. Both the UGV and the UAV mounted DJI Manifold 2-C on-board computer and used a Hokuyo UST-10L laser scanning survey with 270 degrees for sensing.  
Figure 11: **(a–d)** Four sets of translational velocity and rotational velocity distribution of successful path planning in the test, which is the output value of the actor network.  
We conducted obstacle avoidance experiments indoors, as shown in Figure 13. The scene was an indoor environment of 4 m \(\times\) 4 m, and the Vicon indoor positioning system was deployed. Obstacles could be set arbitrarily in the scene. Our experiments had excellent safety and we could choose between manual or automatic mode using a one-to-one pairing remote control. In automatic mode, the controller received a signal from Manifold and used the DRL algorithm for guiding and avoiding obstacles, which made the UGV/UAV fully autonomous. In any case, the manual mode enjoyed the highest control priority ensuring that the entire experiment could be carried out safely.  
The experimental environment of UGV is shown in Figure 13a: UGV experiments with the weights trained by A* optimized SO-DRL. The two experiments of the UGV were from the start point (2, 0) to the goal point (\(-\)2, 0) and from the start point (1.5, 1.5) to the goal point (\(-\)2, 0). The experimental environment of UAV is shown in Figure 13b. UAV is using the weights trained by EGO-Planner optimized SO-DRL. The two experiments of the UAV were from (0,\(-\)1.5, 1) to (\(-\)2, 2, 1) and from (\(-\)1.5, \(-\)1.5, 1) to (\(-\)2, 2, 1). The results show that SO-DRL was able to act with the laser perception only during the driving process to reach the goal point from the start point while avoiding collision with obstacles.
# Entropy Wavelet-Based Method to Increase Efficiency in Highway Bridge Damage Identification
## 3 Damage Identification Methodology and Their Fundamentals
### Entropy-Wavelet Based Method (EWM)
Therefore, damage identification becomes faster and more efficient with the EWM and without sacrificing the precision in damage detection/localization, as will be demonstrated in the next section of this article.
## 4 Robustness of the CATN
### Influence of Structure on CTAN Robustness
In order to investigate the network's robustness following attacks on multiple airports, the attack parameters were adjusted to target multiple nodes simultaneously. Specifically, the authors examined the effects of attacking 5 and 10 nodes at once, evaluating their performance based on the proportion of the maximum connected subgraph and network efficiency. The experimental findings, depicted in Figure 14, reveal that, when multiple airports are targeted, the CATN demonstrates substantial resilience against random attacks but exhibits weaker resistance against betweenness and closeness attacks. Consequently, the network's robustness against attack strategies remains comparable to that observed when targeting a single node. Nevertheless, it is notable that both network connectivity and efficiency deteriorate more rapidly. Figure 13: Temporal changes in network efficiency of four specific time intervals: (**a**) the relationship between weighted network efficiency and the proportion of node removal at 6:00, (**b**) the relationship between weighted network efficiency and the proportion of node removal at 12:00, (**c**) the relationship between weighted network efficiency and the proportion of node removal at 18:00, and (**d**) the relationship between weighted network efficiency and the proportion of node removal at 24:00.
# Paneth Cell, Gut Microbiota Dysbiosis and Diabetes Mellitus
## 5 Limitations  
Some of the limitations of this manuscript include that it is a narrative review and the search was limited to articles that were available through PUBMED and only focused on articles published in English. Unlike in systemic review and/or meta-analysis, there is no standardised way of searching for articles to be included in a narrative review. A narrative review is therefore susceptible to bias during selection of suitable publications. Furthermore, the quality of the studies is not relevant in narrative review. The majority of the studies and publications on Paneth cells and the influence of dysbiosis on DM have been published in the last 10 years. The authors performed an extensive search, and 74% of the articles cited were published within the last 5 years. The inherent weakness of a narrative review is that it is only meant to increase awareness and knowledge of a particular topic and not to support or refute a finding or management approach.  
\begin{table}
\begin{tabular}{c c} \hline
**Derangement** & **Treatment Option** \\ \hline Insulin deficiency & Insulin. \\ Islets cell transplant [213]. \\ Pancreas transplantation [214]. \\ Mesenchymal stem cell [218]. \\ \hline \multirow{4}{*}{In insulin resistance} & Exercise [192,219]. \\  & Lifestyle modification [219]. \\ Oral hypoglyacemics. \\ Insulin. \\ Artificial pancreas [216]. \\ Bariatric surgery [200,220]. \\ \hline \multirow{4}{*}{Dysbiosis} & High-fibre diet [199]. \\  & Low-fat diet [221]. \\  & Low-calorie diet [221]. \\  & Ketogenic diet [198]. \\  & Exercise [52,192,219]. \\  & Dietary supplements [221]. \\  & Probiotics [32,194,195]. \\  & Prebiotics [32,200]. \\  & Metformin [200,222]. \\  & Synbiotics [223]. \\  & Faecal transplantation [115,210]. \\  & Synthetic HD-5 [224]. \\  & Bariatric surgery [225,226,227,228]. \\ \hline \multirow{4}{*}{Increased gut permeability} & Diet [229]. \\  & Glutamine [230]. \\ \cline{1-1}  & Herbal medicines [221,231,231]. \\ \cline{1-1}  & Synthetic HD-5 [226]. \\ \hline \multirow{4}{*}{Inflammation} & Exercise [52]. \\ \cline{1-1}  & Cannabinoids receptor agonists [212]. \\ \cline{1-1}  & Faeces transplant [200,208,209,210]. \\ \hline \multirow{4}{*}{Oxidative stress} & Exercise [219]. \\ \cline{1-1}  & Vitamin C [232]. \\ \cline{1-1}  & Metformin [222]. \\ \cline{1-1}  & Herbal medicines [231]. \\ \cline{1-1}  & Ketogenic diet [205]. \\ \hline \multirow{4}{*}{Pancreatic \(\beta\)-cell dysfunction} & Mesenchymal stem cells [218]. \\ \cline{1-1}  & Islet cell transplant [213]. \\ \cline{1-1}  & Pancreas transplant [214].Stem cell therapy [233]. \\ \hline \end{tabular}
\end{table}
Table 2: List of derangements associated with diabetes mellitus and targeted treatment options.
# A Visual Fault Detection Algorithm of Substation Equipment Based on Improved YOLOv5
## 2 Framework  
### YOLOv5 Algorithm Improvements  
In light of the complex nature, varying defect morphologies, and significant differences in equipment scenes at substations, this paper proposes an improved YOLOv5 object detection algorithm to enhance semantic distinguishability and alleviate global class confusion. The overall network structure is illustrated in Figure 2.  
The main improvements include the backbone network, feature layers, and prediction layers. Firstly, we introduce deformable convolution in the backbone network section to better adapt to changes in target shape by deforming the input feature map. Secondly, instead of PANet, we use a simple and effective BiFPN structure in the neck of the network to fuse multi-level features from the backbone with weighted fusion. The BiFPN structure fully utilizes multi-scale information while having less computational cost and better performance. Finally, we improve the structure of the model's prediction layer by adding a prediction head to handle large-scale variations in targets. These improvements enhance performance in recognizing small targets and improve the adaptability of object detection algorithms for complex scenes and diverse device configurations in substation equipment images. Figure 3 shows the overall algorithm flowchart.
# Towards the Internet of Smart Trains:
## 2 Communication Systems in Railway Scenarios
### Intra-Car Communication Networks
It offers high-speed, low latency, a throughput of up to 7 Gbps with a transmission distance of up to ten meters, and protected connectivity between nearby devices. Its Medium Access Control (MAC) layer is extended and it provides backward compatibility with the IEEE 802.11 standard. When operating in the mmWave domain, beamforming techniques are needed to overcome the path loss from transmitter to receiver, what was not an issue for IEEE 802.11 a/b/g/n due to the use of omnidirectional antennas. On the other hand, Li-Fi (IEEE 802.15) is a 5G Visible Light Communication (VLC) system that makes use of light form diodes to deliver mobile and high-speed communications. For instance, Li-Fi uses amplitude modulation of light sources in accordance to an standardized protocol. Its main drawbacks are that communications require to switch on a light during transmissions and that mobility is not possible. For example, the France's national state-owned company _Societe Nationale des Chemins de Fer_ (SNCF) has been interested in Li-Fi during the last years. For instance, recent applications involving mass-market devices only have DL communications implemented. A project between Lucioum Company and Leti have developed a bidirectional Li-Fi modem that allows for providing wireless Internet access of up to 20 Mbps [27]. Furthermore, Oledcomm provides Internet access via Li-Fi [28]. On-board Internet transmitting via individual lights of the passengers is a topic under research. IIoT can harness the surplus capacity offered by mobile operators in order to provide novel services. In this way, 4G and 5G broadband can help smart railways to attract users from other competing transport means thanks to their coverage and the possibility of offering services like live-video streaming or mobile ticketing. Moreover, safety in railways can be improved through driver advisory systems (i.e., on-board Closed-Circuit Television (CCTV) recordings transferred to a Train Control Center (TCC)), train diagnostics, and driver vigilance detection (for instance, the driver's health can be monitored by using a wireless wearable EEG [29]). Nevertheless, quite a few companies have established a quota limit on throughputs. For example, Amtrak (Washington, DC, USA) blocks the access to streaming media and limits file downloads to 10 MB [30]. Such a quota limit is also employed in the NS Dutch railways, which provide a speed of 150 kbps per user. Most developments were first rolled out in the 2000s, and they have been upgraded with the first deployments of 4G technologies and the usage of the Ka band for satellite communications. Nevertheless, although 5G systems are currently discussed in 3 GPP, commercial devices will not be available until 2020. A recent document that sets out requirements and guidance for Internet provision is presented in [31].