esa-sceva/satcom-chunk-collection huggingface dataset:
## 2 Recent Application of Hyperspectral in Food Authentication
### Fruits and Vegetables  
The use of HSI analysis has been expanded to the analysis of fruits and horticultural products [16; 17; 18; 19; 20]. To increase the classification accuracy and the stability of the prediction model, an approach to evaluate the quality of samples' HSI is needed, accordingly to these authors [16; 17; 18; 19; 20]. The spectral correlation analysis of each pixel is used to determine the quality of the samples analysed using the hyperspectral image system [16]. For example, apple samples (\(n\) = 400) (waxed and non-waxed) were analysed using hyperspectral images where LS--support vector machine (LS-SVM) model was applied to establish the classification model between the hyperspectral image and the fruit treatment (waxed vs non-waxed) [16]. The prediction result showed that the classification accuracy rates were 94% and 86% when the low-quality sample data for training were filtered by spectral correlation analysis [16]. By evaluating the quality of the hyperspectral images measured, more reliable prediction results can be obtained, which can make the non-invasive discrimination of foods according to quality and safety come to the practice application sooner [16].  
The texture of the grain/seeds is a major quality parameter for the acceptability of canned whole beans [17]. Prior knowledge of this quality trait before processing would be useful to guide variety development by bean breeders and to optimize handling protocols by processors [17]. The use of HSI was used to predict texture of canned black beans from intact dry seeds [17]. Spectral pre-processing methods (i.e., smoothing, first and second derivatives, continuous wavelet transform, and two-band ratios) were used to optimize the prediction accuracy of the PLS models developed [17]. The authors showed the great potential that hyperspectral imaging has for predicting the texture of canned beans [17]. In addition, the robustness of the models was influenced by variety, planting year, and phenotypic variability [17]. The authors stated that for canned bean texture robust models can be built based on data sets with high phenotypic diversity in textural properties, and periodically maintained and updated with new data [17].
## 7 Feature Extraction Approaches
### Comparative Analysis
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & & **Strengths** & **Weakness** \\ \hline \multirow{3}{*}{Line-based methods} & These methods demonstrate the ability to acquire data-driven representations and exhibit strong discriminative abilities. & It is essential that the training data represent the classes under consideration comprehensively and accurately. \\ \cline{3-6}  & & High descriptive capabilities coupled with a low computational cost & The sensitivity to the size of the subspace is a significant challenge that requires careful consideration in its application. \\ \hline \multirow{3}{*}{Local direction encoding-based methods} & These methods have a high discriminatory capability and stable characteristics. & They require significant computing resources and contribute to high computational costs. \\ \hline \multirow{3}{*}{Texture based-methods} & Characteristics can be extracted from lower-resolution images, and these techniques exhibit consistent and stable characteristics. & They are highly susceptible to noise interference. \\ \cline{3-6}  & & These methods demonstrate exceptional robustness when applied to large and complex datasets. & They require a significant amount of training data and incur high computational costs. \\ \cline{3-6}  & & & \\ \cline{3-6}  & & & \\ \cline{3-6}  & & & & \\ \cline{3-6}  & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 8: A comparative summary among various palmprint recognition approaches. In summary, there is a compelling opportunity to develop novel and real-time models specifically tailored to unconstrained palmprint recognition. Such advancements are essential to enhance overall performance, achieve a certain level of maturity in the field, and facilitate widespread commercial deployment.
## 6 Protocol Comparison and Security Analysis
### Replay Attacks  
BAPC uses timestamp to defend against replay attacks. During the registration stage, users need to pay legal tender to obtain the corresponding amount of cryptocurrency, and attackers cannot benefit from replaying such messages. During the initial authentication stage and switching authentication stage, the user initiates a transaction to obtain the  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Operation Type** & **Fast-Access** & **Handover** & **BAPC** \\ \hline Hash Operation & \(1/1\) & -/-/2 & -/- \\ Asymmetric Enc/Dec & \(1/1\) & -/-/1 & \(1/1\) \\ Signing Operation & \(1/1\) & \(1/1/1\) & \(1/1\) \\ Signature Verification & \(1/1\) & \(1/\)-/2 & \(1/1\) \\ Communication Times & 2 & 4 & 2 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Calculation comparison of the authentication stage.  
service, and the timestamp is stored in the transaction information. When an attacker replays such messages, it cannot sign them properly or change the timestamp. When the satellite node receives multiple transactions with the same timestamp, it will judge the later one as an invalid transaction and reject the request from the attacker. If the attacker intercepts the request by the user and then replays the request to obtain the service, the session key returned by the satellite is encrypted with the user's public key, and only the user's private key can be decrypted to obtain the session key. Without the private key, the attacker cannot obtain the service. As to resisting replay attacks, BAPC is similar to the method used by traditional encryption protocols and our protocol can also resist such attacks.
## 3 Results and Discussions
### Pozzolanic Reactivity  
#### 3.3.1 Isothermal Calorimetry  
Heat evolution was monitored to determine how blended cements influenced the kinetics of cement hydration using isothermal calorimetry. Figure 5a shows the heat flow of the blended cement pastes up to 60 h, and the amount of heat released throughout the period of hydration is shown in Figure 5b. In comparison to the control paste, calorimetry patterns for the blended cement pastes are anticipated to show higher peaks and acceleration during the hydration reaction. The results showed that the addition of the pozzolans clearly had an impact on the calorimetric properties of the blended cement pastes, especially on the primary peak. The incorporation of calcined clay and silica fume caused an increase in exothermic peak values and a decrease in peak times [35]. It can be seen that ternary mixed cements have substantially longer induction periods than the reference cement does, and that these periods lengthen as replacement levels rise. The long induction period is due to the low kaolinite content of the calcined clay which slowed down the initial hydration process. However, the presence of Al\({}_{2}\)O\({}_{3}\) and SiO\({}_{2}\), especially in the silica fume, hastens the reaction between Ca(OH)\({}_{2}\) from the cement to release heat and eventually enhance the hydration process [36]. Hydration in silica fume-rich pastes were found to be release lower amounts of heat as compared to pastes containing calcined clay. This impact becomes increasingly apparent as the pozzolan content rises, as evidenced in the compressive strength results reported in Section 3.5. Once more, it can be seen that the reference cement peak displays a bump, which often denotes the transformation of afwillite to monosulphate. This peak bump vanished in pastes containing pozzolans, caused by the effectiveness of pozzolanic reactivity [37]. This is in line with previous studies on the  
Figure 4: XRD pattern of hydrated blended cement mortars.  
hydration of ternary mixed cements with various pozzolan contents. It is also observed that, in comparison to the control, pastes containing calcined clay and silica fume reported lower exothermic peak values with shorter corresponding peak periods [21; 38; 39].
## 3 Results and Discussion
### Fatty Acid Analysis  
The extent of fat hydrolysis and the composition of fatty acids are key factors influencing both the flavor and nutritional quality of fermented meat products. In fermented meat matrices, _D. hansenii_ secretes lipase to catalyze fat hydrolysis, producing free fatty acids (FFAs), which are important flavor precursors [2]. In preliminary tests, the strain used in this study also exhibited notable lipolytic activity. Based on these findings, this section explores the effects of exogenous carbon and nitrogen sources on the fatty acid profile in a sausage model. The free fatty acid content in each group after 5 days of fermentation is presented in Table 2. The total FFA content in the FCC group (1251.13 mg/100 g) and the FNP group (1342.92 mg/100 g) was significantly lower than that in the control group (1772.35 mg/100 g), corresponding to decreases of 29.4% and 24.2%, respectively (_p_ < 0.05). Despite the reduction in total FFAs, the carbon and nitrogen source treatments retained sufficient levels of flavor precursors (>1000 mg/100 g). The fatty acid composition in all three groups was similar, with major components including oleic acid (cis) (30%), palmitic acid (25-26%), linoleic acid (16-17%), and stearic acid (13-14%), all of which are important precursors for aldehyde formation, such as nonanal and hexanal. Since there was no significant difference in lipase activity among the three groups, it suggests that the accumulation of free fatty acids may be influenced by factors such as raw material composition, lipid metabolism mechanisms, and the strain's energy supply strategy.
# Bit Rate Adaptation Using Linear Quadratic Optimization for Mobile Video Streaming
## 4 Approach
### Extending LQ for Improving QoE in Mobile Streaming
#### 4.2.4 Download Abandonment  
A sudden bandwidth drop in the mobile environments can cause buffer depletion while a player retrieves a chunk with a selected bit rate. To resolve this problem, if LQE  
\begin{table}
\begin{tabular}{c c c} \hline \hline \(\mathbf{L}\) **(s)** & \(\mathbf{C_{0}}\) **(Mbps)** & \(\mathbf{(K_{P},K_{I})}\) \\ \hline  & 0.5 & 0.0297, 0.0010 \\
5 & 1.0 & 0.0219, 0.0009 \\  & 1.5 & 0.0185, 0.0009 \\... &... &... \\ \hline \hline \end{tabular}
\end{table}
Table 2: Control Gain Table (\(\rho=10^{4}\)).  
Figure 2: LQE Adaptive Bit Rate Selection.  
detects the possibility of buffer depletion while downloading a chunk, LQE abandons the current chunk download and chooses a new bit rate that can finish downloading before a buffer depletion, i.e., a download abandonment is triggered if the buffer level falls below a threshold while the expected remaining download time is longer than the buffer length. For the threshold in our implementation, we use \(\frac{2}{3}B_{K}\) where \(B_{K}\) is the playback buffer level at the beginning of \(k\)-th chunk download.
# A Survey on Massive MIMO Systems in Presence of Channel and Hardware Impairments
## 2 Basic Concepts  
In typical massive MIMO systems, each cell has a BS with large number of antennas, which allows the simultaneous utilization of resources (i.e., frequency band and/or time slots) by different users in the cell. In the following we will introduce the system model and explain the basic concepts of massive MIMO systems in the uplink and the downlink. For simplicity, we consider a single cell scenario with flat fading channels. The extension to frequency selective channels will be straightforward when modulations like OFDM and SC-FDP are employed. Without loss of generality, we assume a BS with \(M\) antennas and \(K\) single atenna users.
## 4 Location Estimation-Based Congestion-Aware Routing Protocol (LECAR)--Detailed Proposal
### Routing Decision Process
#### 4.3.6 Selecting a Custodian  
As stated, the custodian can be the sender or any one-hop neighbor. The sender UAV calculates the \(FC\) value for itself and all pairs of one- and two-hop neighbors. Among the sender and one-hop neighbor of pairs, whichever has the lowest \(FC\) value becomes the custodian.  
In Figure 10, we present a simplified 2D representation of the concept of the \(FC\) calculation. We consider that sender \(S\) is connected to three one-hop neighbors \(n_{1}\), \(n_{2}\), and \(n_{3}\). The two-hop neighbor \(n_{11}\) is connected via \(n_{1}\), \(n_{21}\) and \(n_{22}\) are connected via \(n_{2}\), and \(n_{32}\) is connected via \(n_{3}\). Thus, there are four two-hop neighbors. Considering the one- and two-hop neighbors and the sender, five \(FC\) values are calculated. If the sender has the lowest \(FC\), then the sender is the custodian. Conversely, if the \(FC\) value of any pair is the lowest, then the one-hop neighbor from that pair is the custodian.
## 4 Metal Forging Tools and Moulds Recondition Case Studies
### Case Study 1--Forging Mould Repair
#### 4.1.2 Analysis of Mould Repair Processes (Conventional vs. Hybrid)  
Mould repairs are classified based on the extent of damage: routine maintenance is conducted within the mould's wear limits and comprehensive repairs address significant damage. Comprehensive repairs typically involve two approaches: conventional methods utilising manual welding and mechanical machining or hybrid processes combining metal powder deposition with subsequent mechanical machining.  
Conventional repair techniques involve an initial measurement of the damaged area, followed by manual filling using welding material and CNC-based re-machining. However, for this scenario, the mould's extensive damage necessitated a hybrid repair approach, ensuring improved reliability for high-stress mass production. This hybrid method fuses directed energy deposition (DED) with CNC machining. Beginning with a precise measurement of the damaged area, the process involves depositing metal powder onto the affected region and utilising CNC technology to restore the mould to its original dimensions and shape.
# Development of Patient Specific Conformal 3D-Printed Devices for Dose Verification in Radiotherapy
## 2 Materials and Methods
### Physical Characterization of 3D-Printed Objects  
The tissue equivalency and the geometric accuracy of both the 3D phantom and 3D bolus were evaluated by comparing the CT scanned objects with the original CT scans of the cancer patient. It is known that tissue equivalency of different materials depends on how the density of material correlates with the density of the biological tissue; however, density of material is also one of the most important factors defining X-ray attenuation properties of a material. Using the X-ray visualization technique, the tissue equivalency of material can be derived comparing Hounsfield units, HU (gray scale values at a certain points/regions of the image) for different organs, obtained from CT scans of real patients and CT scans taken of 3D-printed phantom and boluses.  
The geometric accuracy and reproducibility of the 3D phantom was determined in terms of the Dice similarity coefficient (DSC), also referred to as overlap measure, between the CT images of the patient and phantom [26, 27]. Reliable evaluation of DSC has been achieved by properly aligning selected CT scans obtained for both patient and phantom and manually adjusting areas of interest on both images. A DSC value of 1 indicates a perfect overlap between two analyzed volumes. In such case, the 3D-printed phantom would accurately reproduce the contours of patient surface and/or organs. In this work, the similarity coefficient was calculated using the open access software DSCImageCalc (Bradford, UK) [28]. In addition to the Dice similarity coefficient, five additional metrics (Jaccard Coefficient, Proportional Agreement, Cohen's Kappa, Goodman 'I&' Kruskal's Gamma, Rogot-Goldberg Agreement) used in image segmentation analysis (i.e., analysis of shapes and areas) were calculated.
## 4 Numerical Results
### Deck Unseating Damage  
The maximum roller bearing (B2) displacement in negative tangential direction has been established as the damage index to evaluate the potential possibility of deck unseating, as shown in Figure 9. A limit of 0.35 m has been considered to indicate high unseating probability for the viaduct, with narrow steel pier caps that provide short seat widths.  
Absolute values in all cases are less than the limit value, as shown in Figure 10. Maximum bearing (B2) displacement for negative direction presents nearly the same value with the stopper value, except the case of D2000. The stiffness and resistance force of viscous damper are insufficiently large to resist the structure movements. Thus, the stopper prevents the superstructure movements. As the stopper value increases, maximum bearing (B2) displacement for negative direction increases. Maximum bearing (B2) displacement in the case of D2000 also presents a least value. The resistance force and stiffness of D2000 are the largest amongst all the selected viscous dampers. Thus, the movement of roller bearing (B2) is relatively hard compared with other viscous dampers, which leads to the least displacement.  
Figure 8: Acceleration response spectra (\(\xi\) = 0.02). (**a**) Longitudinal direction. (**b**) Transverse direction.  
Figure 9: Schematic of deck unseating.
## 2 VR Applications
### Multiple Players VR Games over Proposed System  
For better illustration of the operation of the cloudlet and other higher layer edge-cloud units, an example of multi-player VR games is considered. In multiple players VR games, players use their VR supported devices to play an intended game, however these games run over the remote application server. In order to reduce the latency and efficient use of energy and computing resources of users' VR devices, the proposed system is introduced. Figure 1 presents the multi-player VR game system runs over the proposed system.  
The VR user with limited computing or energy resources searches, the surrounding, for devices with available computing and energy resources capable of hosting computing tasks associated with the VR game user. These devices are referred to as cloudlet and it may be represented by a powerful smartphone, notebook or tablet. Computing tasks are offloaded from the VR user to the cloudlet over D2D communication interface. WiFi Direct represents an efficient interface and it can be deployed with the method proposed in [6]. The offloading process is held based on the developed algorithm that is introduced in Section 4.4.  
If the VR game user can not find a nearby cloudlet, it turns to offload its computing tasks to the next level of edge-cloud units, which is the micro-cloud edge servers connected to cellular base stations. Micro-cloud edge servers are small edge units that have limited computing and energy resources. These servers are deployed to provide the computing and energy resources at the edge of the RAN and thus, achieve higher latency efficiency and reduce the traffic passed to the core network. Micro-cloud edge servers receive and handle computing tasks from VR users or from corresponding cloudlets that have not sufficient computing or energy resources.  
Based on the available resources and the considered offloading algorithm, micro-cloud edge servers handle the received computing tasks or offload them to the higher edge-cloud units,  
Figure 1: Intelligent core network based on mobile edge computing (MEC) servers with multiple users.  
i.e., mini-cloud units. Each group of micro-cloud units are connected physically with a higher computing and energy capability edge-cloud unit; referred to as mini-cloud. All distributed mini-cloud edge units are connected directly to the core network cloud that represents the interface to the application server.
###### Abstract  
Maritime wireless sensor networks are considered to be the primary means of monitoring methods in the marine environment. The transmission between sensor node and sink node in maritime wireless sensor networks is usually unreliable due to the harsh propagation environment. To extend the transmission range or to enhance the transmission reliability between sensor nodes and sink node, we propose a macrodiversity reception scheme in the sink node equipped with distributed multiple hard-decision receivers. Multiple receivers are divided into several clusters and placed at different locations to receive different signal copies suffering from different fadings. Furthermore, a cascaded combining strategy based on hard-decision information is used to reduce the overall complexity of receiving side. The experimental results in the ocean scenarios show that the macrodiversity reception scheme with two antenna clusters has a transmission gain of 3-4 dB compared with the single antenna reception when the package loss rate is \(10^{-2}\). The study casts a new method for reliable transmission in maritime wireless sensor networks using commercial transceivers which can only output hard-decision results.  
Keywords:wireless sensor networks; macrodiversity; equal gain combining; hard-decision +
Footnote †: journal: Sensors
# A Method for Managing ADS-B Data Based on a 4D Airspace-Temporal Grid (GeoSOT-AS)
## 7 Conclusions  
The focus of this study was to address the needs of ADS-B data organization management and actual airspace management by utilizing the multi-level dissection methods of the GeoSOT grid model. We redesigned and developed a set of grids in GeoSOT-AS specifically for airspace management. The framework was designed to keep the flight space deformation rate low, with a maximum deformation rate of only 16% in China's airworthy airspace. This framework is suitable for current ADS-B data organization, which represents air traffic control. Furthermore, we designed the mapping relationship of the ATC information data structure based on this framework and proposed an information management method with the GeoSOT-AS grid code as the primary key. The primary key management based on airspace grid code is more effective in extraction performance under the task requirement of regional ATC information extraction. We designed two typical experiments: point source information extraction at a global time and fixed time period, as well as airspace information extraction in different scale regions. The results confirmed that the information extraction speed efficiency in the framework of ATC region was improved by about 81%.  
Our future work will concentrate on specific ATC tasks that utilize the airspace grid, including the implementation of airspace use deployment functions based on the GeoSOT-AS framework, and the development of space flight plan anti-collision functions using the airspace grid management concept to integrate additional ATC data. Our goal is to establish a comprehensive ATC database, also referred to as the ATC digital map model, which can be used to support a wide range of algorithmic functions for ATC calculation tasks.  
Conceptualization, C.D. and B.C.; methodology, C.D. and B.C.; experiment, C.D.; writing--original draft preparation, C.D.; writing--review and editing, B.C., T.Q. and S.L.; supervision, C.C. and T.Q. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
The data presented in this study are available on request from the corresponding author.  
The authors declare no conflict of interest.