esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Results
### Performance Results  
Performance tests were executed on the suggested implementation, utilizing the Fabric default test network featuring CouchDB as the state database. The DPP blockchain nodes and the DPP REST API application were both deployed on a single machine equipped with an Intel(r) Core(tm) i7-8565U CPU @ 1.80 GHz \(\times\) 8, 16 GB RAM (equipment source: Asus, Cluj-Napoca, Romania), running Ubuntu 22.04.3 LTS. Apache JMeter 5.6.2 served as the tool for conducting these tests.  
The average response times (for 100 requests, 1 thread) for the primary operations supported by each entity within the data model (such as Manufacturer, Supplier, Product, etc.) are displayed in Table 1.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Pre-existent Number** & \multicolumn{2}{c}{**Get Record by**} & \multirow{2}{*}{**Get Record by**} & \multirow{2}{*}{**Update Record [ms]**} & \multirow{2}{*}{**Delete Record [ms]**} \\ \cline{1-1} \cline{5-5} of Records & & & & \\ \hline
1000 & 35 & 4 & 2052 & 2021 \\
5000 & 138 & 4 & 2072 & 2152 \\
10,000 & 298 & 4 & 2067 & 2073 \\
50,000 & 1394 & 4 & 2082 & 2065 \\
100,000 & 2752 & 4 & 2076 & 2084 \\
1,000,000 & 26,325 & 4 & 2125 & 2091 \\ \hline \hline \end{tabular}
\end{table}
Table 1: The temporal performances of the main operations.  
The findings indicate that the performance of basic CRUD operations remains unaffected by the quantity of existing blockchain records. Swift retrieval by ID is facilitated by the implicit indexing of assets. Create, update, and delete operations consistently consume approximately 2 s each due to necessary blockchain state modifications, involving communication and validation processes. Conversely, retrieving an asset by a different attribute (e.g., DID) experiences significant slowdown, correlating with the dataset's magnitude.  
The initial tests were performed without any additional indexes added to the state database. Finding an asset by DID can be conducted with a regular CouchDB selector, e.g., _[\"selector\": [\"docType\":\"product\",\"did\":\"44d0e672-1b4f436b-93c9 cabffbb9e27\"]_]  
docType serves as a custom attribute integrated into all records, aiding in their categorization by entity types, given the absence of SQL table concepts in CouchDB. Consequently, the index generated for 'get record by DID' encompasses both the DID and docType attributes. Following the index addition, the average response time consistently remained at 10 ms, irrespective of the quantity of records ([1000, 1,000,000]) stored in the database.  
The integration of the CouchDB index into the chaincode involves the placement of a JSON file within the chaincode's primary directory at the specified path: META-INF/statedb/couchdb/indexes. The content of the added index is presented below:  
_[\"index\": [\"fields\": [\"docType\", \"did\"
## 1 Introduction
On the other hand, HF transmission uses the reflection of radio waves in the ionosphere to achieve long range communications in the frequency range from 3 to 30 MHz. The solar radiation ionizes the upper part of the atmosphere and makes the index of refraction change as a function of height, leading to total reflection of the incident wave [15]. Thus, the ionosphere behaves as a communication channel with different layers being highly dependent on the hour, the season, and the solar activity. That means that the HF channel can be modeled as a slow fading multipath channel [16]. HF transmission can be seen as either an alternative to satellite or a complementary backup system in case of failure. In order to optimize the transmission scheme, the channel has to be previously sounded in order to know the variation of the impulse channel response. Second, the best transmission scheme for long haul HF links with extremely low SNR has to be found. The physical layer of 3G and 4G mobile communications has evolved from Direct-Sequence Spread Spectrum (DS-SS) to Multicarrier (MC) modulations. During this time, we have designed both DS-SS and MC proposals adapted to the characteristics of the HF channel. This paper is organized as follows. In Section 2, all the measured parameters are described. All the geomagnetic, ionospheric and communications hardware equipment of the Remote Geophysical Observatory is detailed in Section 3. The tested techniques for transmitting the data through a long-distance HF link are explained in Section 4. Finally, Section 5 contains the main conclusions derived from all the measures registered along the last decade.
# Integrated Optical Phased Arrays for Beam Forming and Steering
## 9 Outlook  
More applications can be achieved based on integrated OPAs. Monolithically integrated OPAs take advantage of full integration and small chip sizes. EF OPAs can be used for 1D beam forming and steering. Wavelength-tuned 1D long-WGA-based OPAs with phase modulations decrease steering complexities in 2D steering. Problems of expensive precisely tunable laser sources [11, 45] and limited performance [64, 84] could be solved. Simplified high-performance on-chip tunable lasers are highly desirable. Large-scale sparse aperiodic 2D OPAs, which have wide FOVs and narrow beamwidths, are promising candidates for high-performance OPA-based applications. Design complexity of large-scale sparse aperiodic 2D OPAs need to be decreased for further applications. A two-chip integrated OPA with a sparse aperiodic aperture might be a promising solution [45].  
For applications based on precise beam forming and steering, WGAs with normal direction radiation [64, 113] as well as structures with plateau envelops [59, 113, 118] can be highly desirable Modulation speeds are greatly enhanced by EO phase shifters based on the carrier density changing function. Monolithically integrated LiNbO\({}_{3}\) EO phase shifters [105] and contact graphene heaters with high efficiencies and operation speeds, low power consumption [75] can be used for excellent EO modulations. To decrease optical losses of sharp waveguide bends, 45\({}^{\circ}\) angle placed antennas may be used to enable optical routing through two sides of the aperture [45]. Fabrication errors need to be carefully treated [142].
# A Novel Multipath Transmission Scheme for Information-Centric Networking
## 5 Performance Evaluation
### Throughput  
Throughput is among the most important indicators of data transmission performance. In this subsection, we simulate the throughput of the multipath transmission scheme under different numbers of relay nodes and different link bandwidths.  
Firstly, we set the number of relay nodes of GEANT2 to 5, 10, 15, 20, 25, and 30, respectively, to analyze the influence of the number of relay nodes on the throughput. The binding relationship between the MPSID and the NAs of these relay nodes has been registered on NRS. Then, we conducted five rounds of simulation. We let the data source node S continuously send data to a receiver node (C1 to C5), respectively, in each round and measured the steady-state throughput. As shown in Figure 4, it can be observed that when the number of relay nodes is ten, the average throughput can reach a maximum of about 169 Mbps. When the number of relay nodes is five, the average throughput is close to the maximum. This means that using only a few relay nodes can significantly improve the efficiency of multipath transmission. However, as the number of relay nodes increases, the average throughput decreases instead. The reason is that too many candidates increase the complexity of path selection and switching algorithms, so that it cannot quickly converge to the optimal relay. According to the experimental results, we set the number of relay nodes to ten in the following section.  
Secondly, we simulated the average throughput under different bandwidths by changing the link bandwidth between the backbone nodes of the topology to 50 Mbps, 100 Mbps, 150 Mbps, and 200 Mbps, respectively. The experimental results are shown in Figure 5. It can be seen that the average throughputs of the single path method under different bandwidths were roughly 47 Mbps, 91 Mbps, 134 Mbps, and 179 Mbps, which is the lowest among the three methods. This is because the single path method cannot take advantage of other paths other than the default shortest path. It can also be observed that under different bandwidths, ECMP can improve the average throughput to about 62 Mbps, 113 Mbps,  
Figure 3: Simulation topology (GEANT2).  
158 Mbps, and 201 Mbps, respectively, but the improvement is not obvious. The reason is that ECMP is not always effective, since it only works on symmetric links. The symmetric links generally exist in data center networks [49], such as Fat-tree topology and Clos topology, but rarely exist in carrier networks or WANs. Compared with the other two methods, our proposed multipath transmission scheme can achieve the highest steady-state throughput under different link bandwidths, which are about 88 Mbps, 169 Mbps, 247 Mbps, and 302 Mbps, respectively. This also shows that our proposed method can achieve a significant improvement in average throughput.
# A Method for Adapting Stereo Matching Algorithms to Real Environments
## 2 Related Work
### Stereo Matching Algorithms  
There is a large variety of stereo matching algorithms. Many of them are listed in the rankings of this kind of algorithm. The Middlebury Stereo Evaluation--Version 3 ranking contains 247 algorithms as of 23 August 2024 [3]. The KITTI Vision Benchmark Suite [4] includes 340 algorithms as of 23 August 2024.  
As mentioned in the introduction, in the case of most of these algorithms, their source codes are not provided by the authors; this makes it hard to verify their functionality. However, there are also algorithms that are usable in real environments. One such algorithm, for example, is the well-known Semi-Global Block Matching (StereoSGBM) algorithm, which has been implemented in the OpenCV library [6]. The algorithm was derived from the work of [PERSON] [34].  
Stereo cameras also have some limitations. In particular, they make obtaining data for objects with transparent or reflective surfaces problematic. Flat surfaces of the same color are also problematic because it is hard to match parts of objects that are visible in one image with the corresponding visible parts in other images when using a stereo camera.
## 2 Minimally Invasive Therapies for HCC and Their Tissular Effects
### Thermal Ablative Therapies
#### 2.1.1 Radiofrequency Ablation  
Radiofrequency ablation (RFA) is commonly reserved for patients with HCC nodules smaller than 5 cm and several randomized trials have shown it to yield a 94% or higher complete response rate as well as a 54% or higher 5-year survival [22; 23; 24; 25; 26]. RFA essentially relies on tumor destruction through extreme heat obtained through high-frequency radiowaves between 460 and 480 kHz, but the range may be extended in some cases to 375-500 kHz or beyond [27]. The alternating electrical current travels through the path of least resistance and produces frictional heat (\"electrical sink\" effect) through ion agitation, which is focused inside the tumor nodule, inducing cellular damage [28]. When temperatures in the tissue reach 60 \({}^{\circ}\)C, instant coagulation of proteins and destruction of cellular components is obtained; however, exceeding 100 \({}^{\circ}\)C causes fluids to boil with vaporization that implies gas release in the area of ablation; this insulates the tissue and hampers the procedure [28; 29]. Moreover, blood vessels can carry away the electrical current from the vicinity of the electrode, thereby decreasing the overall temperature in the region (\"heat sink\" effect), diminishing the effectiveness of the procedure and allowing for the possibility for some tumor cells to survive [22].  
After several seconds of application, RFA induces an ellipsoid volume of coagulation necrosis in the targeted area around the electrode. Animal studies have shown that the histopathological changes induced by RFA are heterogeneous, with a central area of carbonization along the trajectory of the electrode surrounded by an area of necrosis and a peripheric hemorrhagic hemorrhagic rim [30]. Moreover, the hemorrhagic rim appears to be surrounded by a fibrovascular halo that thickens over time [31]. There are reports that suggest that cell proliferation is stimulated within the hemorrhagic area and this mechanism could be responsible for the appearance of tumor recurrence [32]. Liver capsule retraction may be observed in the ablation of superficial tumors [33] (Figure 2).  
Figure 1: Overview of the thermal ablative therapies and their effects. RFA = radiofrequency ablation, MWA = microwave ablation, LA = laser ablation, HIFU = high-intensity focused ultrasound; CA = cryoablation.  
In order to perform a successful procedure and ensure all viable tumor cells are destroyed, a tumor-free margin of at least 1 cm thickness should be obtained around the tumor nodule [28].
# Hybrid Renewable Systems for Small Energy Communities: What Is the Best Solution?
## 3 Case Study
### Results and Discussion  
A total of four solutions were assembled, two stand-alone and two grid-connected solutions, which combine different renewable energy sources and energy storage mechanisms. The following section presents their technical capabilities and assesses their economic comparison, obtained by the defined optimization method, that minimizes the total installed capacity of the small energy community.  
The stand-alone setup examines a microgrid solution. It is entirely independent from the external electric grid, through two similar configurations, with the corresponding designations: **SA1--**PV + Wind + PSH and **SA2--**PV + Wind + PSH + BESS. The grid-connected (GC) setups (i.e., **GC1--**PV + PSH + Grid and **GC2--**Wind + PSH + Grid) explore the small energy community solution that maintains synchronization with the national electric grid. Nevertheless, to prevent the grid from unduly influencing the system's operation and deviating it from the intended purpose of a microgrid, it is essential to establish two validation criteria. The solution must be at least 80% independent from it and have more energy export than import.
## 3 System Model and Problem Statement
### Problem Statement  
Many traditional routing protocols can improve the performance of energy efficiency and network lifetime by introducing intelligent clustering methods or considering residual energy, _etc._ However, most of these energy efficient routing protocols do not consider the energy consumption under various traffic models, which is an important factor that influences the hotspot problem.  
Figure 3 shows the distribution of hotspot nodes with circles under our previous work in [5], where BS is placed inside at (150, 150) in Figure 3(a) and outside at (150, 400) in Figure 3(b). The hotspot nodes are close to the BS since multi-hop routing is favorable in most cases. Even though our HEAR algorithm in [5] can largely reduce energy consumption and prolong network lifetime to certain degree, it cannot avoid the hotspot problem due to its intrinsic nature of minimizing the total energy consumption during certain route. In other words, if we aim to prolong and maximize the network lifetime, the final objective function should be let each sensor consume their energy at similar rate (\(E_{I}\approx E_{2}\approx\cdots\approx E_{n}\)) rather than to \(Min\underset{i=1}{\overset{n}{\sum}}E_{i}\)) for the \(n\)-hop route.  
**Figure 3.** Hop spot nodes under HEAR algorithm **(a)** when BS is inside; **(b)** when BS is outside.
## 3 The Proposed Architecture
### Physical Sensing Layer  
The physical sensing layer contains physical devices such as sensors, a wireless sensor network (WSN), a wireless body area network (WBAN), QRCode and RFID components. The security threats related to the physical layer are eavesdropping, cyber-physical attacks, jamming, RFID and spoofing. Authentication, Faraday cage and PRESENT are the effective security solution to preserve IIoT networks from physical sensing threats.  
In the proposed architecture, we have classified the common attacks (in the right side) in the IIoT network according to the corresponding layer. For example, the spoofing attack could target a sensor in the physical layer. On the other hand, the security solutions are classified according to the corresponding layer. For instance, the authentication mechanism is a solution against a spoofing attack.
# Coupled Spatiotemporal Characterization of Monsoon Cloud Cover and Vegetation Phenology
## Materials and Methods
### Data and Preprocessing  
17 years of MODIS collection 6 near-daily surface reflectance imagery were acquired free of charge from the NASA REVERB data hub ([[https://reverb.echo.nasa.gov/](https://reverb.echo.nasa.gov/)]([https://reverb.echo.nasa.gov/](https://reverb.echo.nasa.gov/))). Data drop outs were excluded by flagging acquisitions with only partial coverage (swath edges) and those with large areas of missing data, yielding a total of 4236 images. Data corruption, indicated by anomalous reflectance values, was particularly obvious in three years (2002, 2011, and 2016). These years were excluded from the calculation of the covariance matrices on which the EOF analysis was based. NDVI was computed at 250 m resolution and all of the images were stacked into one data cube.
# Shared eHMI: Bridging Human-Machine Understanding in Autonomous Wheelchair Navigation
## 4 Results and Discussion
### Discussion  
#### 4.3.1 Enhancing Understanding and Safety through Transparent Communication  
The complexity of wheelchair scenarios presents significant challenges for autonomous driving. Emotional concerns about potential risks, such as the shadow of disability, pedestrian collision and machine malfunction experiences, and machine malfunctions, may decrease users' sense of safety, trust, and acceptance of autonomous driving. Research indicates that promoting transparent communication can increase user trust, safety, and acceptance of autonomous driving systems [63].  
The shared eHMI enhances system transparency by projecting the user interface, showing the anticipated path and interpreting the world, thereby informing users about the immediate driving statuses and intentions of the autonomous wheelchair. This approach allows users to observe, feel, and understand the behaviors of the autonomous mechanism more intuitively compared to relying on memory or mobile navigation.  
Some participants reported that the user interface's information exceeded expectations, enhancing the sense of intelligence and helping build trust. Specifically, clear navigation path helped alleviate concerns about getting lost, real-time feedback on speed and destination proximity were very helpful, and obstacle avoidance and yield behavior reduced risks of falls and collisions with obstacles or pedestrians. Most participants appreciated its innovation, but the UEQ-S results showed a higher hedonic than pragmatic quality, likely due to limited simulated scenarios and absence of real-world testing.
# Visible Light Communication System Technology Review: Devices, Architectures, and Applications
## 6 VLC Application
### Vehicle to Vehicle Communication  
Front-end collision warning, pre-collision sensing, emergency stop lights, lane change warning, parking movement assistance, left turn assist, signal violation warning, and corner speed limit warning are among the most important vehicle safety communication initiatives [129]. A Li-Fi high-speed visible light communication system can be employed for these, since all high-priority applications require extremely low latency reachability and the permissible delay of vehicle safety communication is ultra-low.
# Efficient Secure Routing Mechanisms for the Low-Powered IoT Network: A Literature Review
## Security Issues and Challenges in WSN-IoT  
### Data Confidentiality  
In the field of WSN-IoT and network protection, data secrecy is a critical concern. The client has access to the details and the system management in WSN-IoT frameworks. The IoT device should check that the user or machine has been granted access to the system [50]. Approval determines whether a person or device can receive assistance after presenting distinguishing evidence. Access management restricts property access by granting or refusing permission based on a series of laws. Creating a secure connection between devices and services necessitates approval and access control. The main point is creating a specific relationship between other devices and administrations, which requires  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Sr. No**} & **Security Objectives of WSN-IoT** & **Definition** & **Layers** \\ \hline
1 & Availability & Accessibility is the nature of keeping the service & \\  & & accessible for clients. & Perception Layer \\ \hline
2 & Accountability & Accountability is one of the IoT frameworks’ & \\  & & basic properties, but it cannot preempt network & Network Layer \\  & & attacks and IoT vulnerabilities. & \\ \hline
3 & Confidentiality and Privacy & Confidentiality is otherwise known as as secrecy; & \\  & & to fulfill the security requirements, it is & \\  & & implemented to prevent unauthorized clients & Network Layer \\  & & from getting information. & \\ \hline
4 & Auditing & This is an essential component; without it, the & \\  & & framework’s criteria for meeting security & \\  & & requirements will not be accomplished. It is used & \\  & & to recognize the security shortcomings of the IoT. & \\ \hline
5 & Integrity & It enables legitimate and authorized access to & \\  & & modify data following requirements, but only & \\  & & under certain conditions. & \\ \hline
6 & Access Control & It gives clients/users explicit roles or verified & \\  & & admittance to utilize network assets to view, & \\  & & alter, or modify data. & Application Layer \\ \hline
7 & Authentication and & Authentication is the user’s verification, which is & \\  & & the primary security necessity as it recognizes & \\  & & users as validated clients utilizing security & \\  & & frameworks such as cryptography algorithms. & \\ \hline \hline \end{tabular}
\end{table}
Table 2: Security objectives of WSN-IoT.  
support and access control. The most critical problem in this situation is making access management regulations easy to develop and understand. This is a vital issue in the Internet of Things; many clients, objects, and devices must verify each other through trustworthy administrations to gain system access. The problem is to find a solution for safely dealing with the client's personality, items, and gadgets [51; 52].
## 5 Methodology
### Feature Extraction
#### 5.1.2 Laser Reflectance Data  
In this study, laser reflectance features were used to detect changes on the surfaces of the fish. For this purpose, reflectance information from nine laser channels directed at the fish body during each measurement was recorded as histograms with 128 time bins. These histograms represent the ToF distribution of photons reflected from the fish surface. Each value obtained from the histograms shows an instantaneous measurement of the interaction of the laser light with the fish tissue.  
The laser sensor was fixed at a 3 cm distance from the fish surface, meaning that the earliest bins in the histogram contained reflections directly from the fish skin. In contrast, later bins predominantly capture delayed, scattered, or weak signals that often carry minimal or noisy information. An analysis of the data showed that these later bins contained high sparsity and near-zero intensity in most cases. Therefore, only the first fifteen bins from each of the nine channels were used as features, resulting in 135 laser-based descriptors per sample. This approach reduces the dimensionality while retaining the most physically and biologically relevant information for freshness assessment.