esa-sceva/satcom-chunk-collection huggingface dataset:
## 1 Introduction  
The air/aqueous tear interface is stabilized by a viscoelastic tear film lipid layer (TFLL). The TFLL consists of a 2.5-3 nm thin monolayer of amphiphilic polar lipids (PL; mainly (O-acyl)-\(\omega\)-hydroxy fatty acids) at the aqueous interface, overlaid by a thick (>70 nm) stratum of non-polar lipids (NPL; wax and sterol esters, triacylglycerlycerides) facing the air. Both PL and NPL are delivered primarily by the Meibomian gland secretion (MGS or meibum) and therefore Meibomian gland disease (MGD) results in a deficient or dysfunctional TFLL [1; 2; 3; 4; 5; 6]. Currently MGD is considered to be the main reason for dry eye syndrome (DES), which affects the vast majority of dry eye sufferers across the globe [7; 8].  
Thus, it is important to study how the surface properties of \"normal\" Meibomian gland secretion (nMGS) collected from healthy individuals, and meibum from patients with Meibomian gland dysfunction (dMGS) differ between each other. Multiple in vitro and in vivo reports have found that dMGS displays deteriorated interfacial and viscoelastic properties compared to nMGS, and one goal of this study was to further deepen this knowledge via detailed biophysical characterization of the samples [1; 2; 3]. Langmuir surface balance measurements have proven to be an effective approach for assessing the interfacial properties of MGS films during blink-like area changes that are relevant to physiological conditions [2]. These measurements have also been successfully applied in the development and characterization of ophthalmic formulations [9; 10; 11; 12]. The reorganization of the layers upon blink-like cycling and their dilatational elasticity were investigated using surface pressure (\(\pi\))-area (A) isocycles and stress relaxations, respectively. Additionally, Brewster angle microscopy (BAM) was employed to access the structure of the films. Furthermore, the brittleness of healthy and diseased MGS films, i.e., their capability to maintain constant surface area at a fixed surface pressure, was also probed.  
Another goal was to see whether the supplementation of dMGS with Rohto Dry Aid (RDA), a novel ophthalmic nanoemulsion that uses TEARSHIELD TECHNOLOGYTM to simulate normal tears and restore moistness, can recover the structure and functionality of the diseased Meibomian films, since the formulation was recently shown to facilitate the performance of \"healthy\" Meibomian lipids [12]. Sesame oil (SO) is implemented in the RDA oil phase as an NPL substitute, while a mixture of polyoxyethylene castor oil 10 (CO-10), polyoxyl 40 stearate (MYS-40), and menthol was chosen to emulate the PL. Sesame oil's composition of monounsaturated, polyunsaturated, and saturated fats has been previously shown to properly supplement the NPL stratum of human meibum layers [9].
# A Context-Aware Edge-Based VANET Communication Scheme for ITS +
## 3 Propose Scheme
### Criteria for Edge Node Selection  
The proposed scheme selects the edge nodes using a distributed approach. The vehicle velocity, the vehicle distribution, and the channel conditions (link qualities) between the edge nodes and ordinary nodes are taken into account for the edge node selection. The consideration of vehicle velocity is to select slower vehicles as possible in order to avoid the overhead that could possibly occur due to the frequent change of edge nodes. The vehicle distribution is considered using the number of  
Figure 1: Edge-based forwarding.  
neighbors moving to the same direction which can reflect the long-term vehicle movement (in a two-way road, the edge nodes should be selected from the vehicles that have more vehicles moving toward the same direction). The link quality is also an important metric because a node that has better connections (for example, higher antenna height) with other non-edge nodes is preferred. A fuzzy logic-based approach is used to integrate these three metrics in the evaluation of the fitness for being an edge node.  
In the proposed scheme, the vehicle velocity and the number of neighbor vehicles driving to the same direction are exchanged by hello messages. Each node calculates a competency value (as being an edge) for itself and each neighbor vehicle. If the node has the largest competency value in its vicinity (\(\frac{R}{2}\) where \(R\) is the average transmission range), the node claims itself as an edge node in the next hello message. Edge node selection is conducted on a road segment basis which is defined in [23]. This ensures the connectivity between the selected edge nodes.
## 2 Study Area and Data
### Sentinel-1 Data  
The SAR data used in the study are C-band Sentinel-1 data. Sentinel-1 is an important constellation system in the Copernicus Program of the European Space Agency (ESA) ([[https://browser.dataspace.copernicus.eu/](https://browser.dataspace.copernicus.eu/)]([https://browser.dataspace.copernicus.eu/](https://browser.dataspace.copernicus.eu/)), accessed on 8 May 2024), comprising the Sentinel-1A and Sentinel-1B satellite, and the satellite data are available for free. Sentinel-1A was launched on 3 April 2014, and Sentinel-1B on 25 April 2016. Positioned 180\({}^{\circ}\) apart in the same orbit plane, they conduct the same site observations every 6 days. Regrettably, Sentinel-1B ceased data acquisition due to a malfunction by December 2021.  
The Sentinel-1 data are acquired in interferometric wide swath (IW) mode with a spatial resolution of 20 m. In this study, the Level-1 Ground Range Detected (GRD) product was collected on the Google Earth Engine (GEE) platform. The specific data processing workflow are explained in the Section 3.  
Based on existing studies [17; 31], only VV polarization data were used in this study because they are more suitable for identifying the ROD. Due to the rapid changes in snow cover, the revisit cycle of Sentinel-1 images directly determines the accuracy of ROD identification. We conduct an annual count of the number of Sentinel-1 images corresponding to the snowmelt period (set from 1 February to 31 July in the study) for each station within the study area since 2014 (Section 2.3). The results indicate that the number of images in the melting period of the stations from 2014 to 2016 is generally less than 20, which can hardly meet monitoring requirements. Therefore, we collect the Sentinel-1 data from 2017 to 2023 in this study (with the dataset containing only Sentinel-1A data after December 2021), and explore its accuracy in extracting the ROD under different land cover types.
# Impact Characteristics of a Bidirectional Pneumatic DTH Hammer for Unconsolidated Formations
###### Abstract  
With advantages of high efficiency and low cost, DTH hammer drilling has been highly applied in various drilling projects. When drilling in unconsolidated formations, it is prone to drilling accidents such as drilling tools sticking or burying. Thus, a bidirectional pneumatic DTH hammer is designed to drill boreholes using forward impact and release sticking drilling tools using backward impact. With a floating gas distribution mechanism, impact strokes of the DTH hammer piston can be changed when flat keys are in a different position of the key grooves on the gas distribution shaft. In drilling mode, the piston has a larger impact stroke and can impact the anvil at high speeds to drive the bit breaking rocks. When drilling tools become stuck, by changing to a smaller impact stroke, the piston can impact backward on the gas distribution valve to break rocks above the DTH hammer so sticking drilling tools can be released. According to the structure and working principle of the bidirectional pneumatic DTH hammer, a physical model based on the pneumatic transmission circuit is established; then, a simulation model is built with pneumatic transmission module components in software of SimulationX 4.1 student version. Piston velocities, displacements, and impact energy are analyzed, with main factors including piston mass, total weight of the DTH hammer, compressed air pressure, and backward impact stroke being considered. Analysis results show that working characteristics of the DTH hammer are fairly affected by piston mass and compressed air pressure. Based on the changing laws of the impact frequency, peak of impact velocity, and impact energy, a piston mass of 18 kg, total weight of 125 kg, gas source pressure of 2.2 MPa, and lifting distance of 60 mm for backward impact were recommended. To verify the performance of the bidirectional pneumatic DTH hammer, field experiments were carried out in the gravel stratums. The bidirectional DTH hammer was in good working condition and the maximum drilling rate can reach up to 1.5 m/min. By lifting the DTH hammer away from the bottom of the borehole and pumping compressed air, the DTH hammer piston could achieve a high frequency backward impact. There are no drilling tools' sticking or burying accidents in the drilling experiments. The bidirectional pneumatic DTH hammer can effectively drill boreholes in loose formations and deal with drilling tools' sticking or burying accidents.  
pneumatic DTH hammer; unconsolidated stratum; bidirectional impact; piston speed; impact energy +
Footnote †: journal: Applied Sciences
# OpenCare5G: O-RAN in Private Network for Digital Health Applications
## 4 Experimental Evaluation
### Results and Discussion  
The tests carried out for the use cases of data received and sent from exams, images, voice and text to evaluate the data transmission capacity of 5G connectivity demonstrated the effectiveness of our methodology.  
PoC-1 evaluated the connectivity of the 5G network in terms of transmitting USG images in a product already commercially available that benefits from a dedicated communication platform, Reacts. Hence, with a specific product that offers the opportunity for collaboration, the project team can have answers to questions that are still unanswered. In fact, the project aims to cover a large number of portable USG equipment to perform USG exams in remote locations. In view of the above, the scenario proposed for the examination follows the expected scope, and we collectively chose to consider the PoC satisfactory, due to the limitations found.  
Figure 20 presents the results of the second phase of the 5G private network test for PoC-2-1, which are also reported and discussed in Table 2.  
Figure 20: Boxplot of tests in the second phase of the 5G private network for PoC-2-1. (**a**) Test 1: VNC; (**b**) Test 2-1: VNC; (**c**) Test 2-2: PACS; (**d**) Test 3-1: VNC; (**e**) Test 3-2: PACS; (**f**) Test 4-1: VNC; (**g**) Test 4-2: PACS. BCD: Bandwidth Consumption in Download; BCU: Bandwidth Consumption in Upload; L: Latency.
# Analytical Modeling of the Maximum Power Point with Series Resistance
###### Abstract  
This paper presents new analytical expressions for the maximum power point voltage, current, and power that have an explicit dependence on the series resistance. An explicit expression that relates the series resistance to well-known solar cell parameters was also derived. The range of the validity of the model, as well as the mathematical assumptions taken to derive it are explained and discussed. To test the accuracy of the derived model, a numerical single-diode model with solar cell parameters whose values can be found in the latest installment of the solar cell efficiency tables was used. The accuracy of the derived model was found to increase with increasing bandgap and to decrease with increasing series resistance. An experimental validation of the analytical model is provided and its practical limitations addressed. The new expressions predicted the maximum power obtainable by the studied cells with estimated errors below 0.1% compared to the numerical model, for typical values of the series resistance.  
maximum power point; series resistance; Lambert's W function; analytical expressions 1
# A Road Truncation-Based Location Privacy-Preserving Method against Side-Weight Inference Attack
## 4 Problem Formulation and Proposed Scheme
### Cost Model  
In this section, we discuss the cost model for LBS. This cost model will be used to evaluate the efficiency of the privacy preserving algorithm. Take the POI as an example, the cost is calculated in detail. A typical example of POI is to find the \(k\) nearest objects, namely k-nearest-neighbor (k-NN) query. In order to protect location privacy, the location information is an anonymous area containing the user. The user is either in the internal area or on the border of the anonymous set. Base on this, we divide the query cost into two parts. The cost of the inner search is the size of the anonymous set. The outer search is to find the objects closest to the marginal nodes. We define the query execution cost of a private query as:  
\[Cost(S,n)=E(S)+V_{o}(S)\times n, \tag{5}\]  
where \(E(S)\) stands for the number of edges in anonymity set \(S\), \(V_{o}(S)\) stands for the number of marginal nodes and \(n\) stands for the number of query objects required by the user.  
In order to protect location privacy, many users and edges are added to the anonymous set \(S\), which will increase the query cost. Therefore, the algorithm should reduce the cost as much as possible on the premise of privacy protection. Based on the discussion above, we formulate the problem as,  
\[\min_{\{a_{i}\}} Cost(S,n)\] (6a) s.t. \[k\geq k_{0}, \tag{6b}\] \[l\geq l_{0},\] (6c) \[\lambda\leq\lambda_{0}, \tag{6d}\]  
where constraint Equations (6b) and (6c) are integers, and Equation (6d) is fractional. Thus, the problem is a mixed integer program problem. We give a heuristic algorithm in the next section, as the problem is a non-convex optimization problem.
# Antenna Design for Microwave and Millimeter Wave Applications: Latest Advances and Prospects
## 9 Quasi-Yagi Slotted Array Antenna with Fan-Beam Characteristics for 28 GHz 5G Mobile Terminals  
[PERSON] et al. [8] proposed a quasi-Yagi slotted array antenna with fan-beam characteristics for 28 GHz 5G mobile terminals. The antenna was composed of a 1 \(\times\) 8 slot antenna array with directors to enhance the half-power beamwidth (HPBW). The proposed antenna had a fan-beam radiation pattern with a simulated HPBW of 256.72\({}^{\circ}\) and a peak gain of 11.16 dBi. In addition, the proposed antenna covered \(\pm\)48\({}^{\circ}\) using a beam steering mechanism. Mutual coupling reduction was achieved by inserting slits between the adjacent slot radiators on the ground plane. The simulated \(-\)10 dB reflection coefficient bandwidth of the proposed antenna was 1.79 GHz (27.03-28.82 GHz), and the mutual coupling between each of the slot radiators was lower than \(-\)25.02 dB over the 28 GHz target band (27.5-28.35 GHz). To investigate the effect of a human body in a practical environment, the power density was considered to estimate the electromagnetic exposure with a simplified skin model. The measured results were in good agreement with the simulated ones and demonstrated that the proposed antenna could be used for 5G mobile terminals.  
Low-Profile Spidron Fractal Dipole Antenna with a Ferrite-Loaded Artificial Magnetic Conductor for Manpack Applications  
[PERSON] et al. [9] presented a Spidron fractal dipole antenna with a ferrite-loaded artificial magnetic conductor (AMC). By applying ferrite composed of nickel-zinc with a high permeability value, a compact AMC operating in the broadband frequency range within the high-frequency/very-high-frequency/ultra-high-frequency (HF/VHF/UHF) bands was designed. A Spidron fractal-shaped dipole antenna with a quasi-self-complementary structure was designed and combined with a miniaturized ferrite-loaded AMC. This allowed the designed AMC-integrated dipole antenna to operate in a wide frequency band, covering the HF/VHF/UHF bands, with low-profile characteristics. A prototype of the proposed Spidron fractal dipole antenna with the AMC was manufactured and measured and found to meet low voltage standing wave radios (VSWR) specifications of \(<\)3.5 within the 20-500 MHz bandwidth range. The simulated and measured results were in good agreement.  
The size of the Spidron fractal dipole antenna with the AMC was 0.03 \(\times\) 0.026 \(\times\) 0.001 \(\lambda^{3}\) relative to the wavelength of the lowest operating frequency. The received power of the Spidron fractal dipole antenna with the AMC was also measured when it was applied to relatively small applications, such as a manpack in this case.
## 5 Discussion
### Research Limitations  
Despite its contributions, this study has some limitations that should be considered for a comprehensive understanding of the results:  
* Sampling Method: This study employed a convenience sampling method, which presents certain disadvantages compared to random sampling [34]. While this approach allowed for the collection of data from a sizable group of Costa Rican university students, it does not ensure that the findings are fully generalizable to the entire population. Convenience sampling may introduce selection bias, as participants who voluntarily engage in the study might differ in meaningful ways from those who do not. This could result in estimates of the relationships between the UTAUT2 model variables that are not entirely reflective of the broader student population. Future research should aim to replicate this study using random or stratified sampling techniques to enhance the representativeness of the sample. Additionally, weighting techniques could be applied in data analysis to adjust for potential sampling imbalances.
* Self-Reported Data: The data collection instrument relied on self-reports, which have inherent limitations [35]. Self-reported measures are susceptible to social desirability bias and recall bias, which may affect the accuracy of responses. For instance, students may overestimate or underestimate their use of ChatGPT due to perceived expectations or memory constraints. However, as [PERSON], [PERSON], and [PERSON] [36] point out, obtaining objective measures of technology acceptance is challenging, unless the technology is used consistently.
* Lack of Qualitative Insights: This study relied exclusively on quantitative data collected through structured questionnaires, which limits the ability to capture students' nuanced perceptions, motivations, and challenges in adopting ChatGPT. While the UTAUT2 model provides a strong framework for measuring technology acceptance, qualitative methods, such as interviews, focus groups, or open-ended survey questions, could provide a deeper contextual understanding of the observed statistical relationships.
* Ex Post Facto Design: The ex post facto methodological design prevents the establishment of causal relationships between the analyzed variables. Although structural equation modeling (PLS-SEM) was used to infer relationships between constructs,this approach does not replace experimental or longitudinal designs in terms of causal inference.
# Bridge Model Updating Based on Wavelet Neural Network and Wind-Driven Optimization
## 5 Finite Element Model Updating of Ningbo Bund Bridge  
In this section, the proposed is implemented on the model updating of Ningbo Bund Bridge, updating parameters are selected based on sensitivity analysis, WNN is established, and model updating is then carried out based on static and dynamic responses of the structure.
# MAC Protocols for mmWave Communication: A Comparative Survey +
## 4 Centralized Protocols
### D2 dmac  
Dense deployment of small cells in the 60 GHz mmWave networks is gaining popularity with the deployment of 5G networks. The device-to-device MAC (D2D-MAC) protocol [45] is a frame-based protocol which is suited perfectly for dense mmWave small cells, and it can perform radio access and backhaul operations simultaneously. In this protocol, a frame can be divided into two stages: scheduling and transmission phases. In the first stage, the nodes of the system steer their antennas to their respective AP. Subsequently, according to the traffic demand of each node, each AP node relays the traffic demand status to the central controller with the help of a backhaul link. The controller node manages and schedules the traffic of all the established links in the network.  
Later, on the second stage, based on the allocated schedule instructions, the nodes and the APs exchange data packets and establish the traffic flow with each other. This stage is called the transmission stage. At this stage, nodes can establish multiple simultaneous links. Moreover, finding these possible and optimal transmission paths among the nodes and APs are also controlled by the central controller. The protocol highly emphasizes the direct transmission links between two nodes. In order to achieve the near-optimal performance of indirect transmission path planning, the protocol always considers a path containing high channel quality.  
Meanwhile, [PERSON] et al. [46] also proposed another D2 DMAC for the mmWave with a combination of 4G system architecture with a TDMA-based MAC structure as a possibility for 5G cellular networks, with the 4G system performing the control operations. Due to the large capacity of mmWave communications, traffic can be offloaded from macrocells and improved services can be provided for traffic with high throughput needs. Concurrently, handovers between the macrocells and AP BS in the mmWave band, on the other hand, can deal with issues such as blockage, mobility management, and load balancing.  
* Advantages: The D2D-MAC is primarily focused on its optimal application in the mobile access network, making it an appropriate candidate for small cell cellular networks. It has an optimal path selection criterion between the multiple small cells. It reduces the number of time slots required to facilitate all traffic flows. In addition, the small cells have the features to provide high speed data linking at high frequencies within a small coverage.  
Disadvantages: In D2D communication, setting up a direct LoS link requires users to discover each other. Inter-inference between devices poses a significant challenge in neighbor discovery. In addition, mode selection and synchronization is still an issue which remains in D2D protocols and communication.