esa-sceva/satcom-chunk-collection huggingface dataset:
## 2 Sensible Heat Storage (SHS) Method
### Sensible Heat Storage in Porous Media
As an example, the energy efficiency increased from 31% to 68.2% when the porosity increased from 0.6 to 0.8, respectively, for a given flow pulsation amplitude. The same shall apply to exergy efficiency, which goes from 32.4% (for \(\varepsilon=0.6\)) to 67% (for \(\varepsilon=0.8\)). [PERSON] et al. [44] achieved four physical models through numerical simulations to describe the thermal behavior of a packed bed for sensible heat storage. They particularly discussed the porosity influence on the packed bed during charging and discharging periods. They demonstrated that a decrease in porosity improves the thermal storage capacity of the packed bed and increases the interstitial heat transfer between the coolant and the solid particles. Furthermore, they noted that high porosity slows down the charging process. [PERSON] et al. [50] presented a review of numerous models to simulate nanofluid flow physics in a porous medium. They gathered details on the main features of a porous structure embedded in thermal systems such as heat exchangers and ducts. They stated that the use of a porous matrix extends the specific interface area between the porous  
Figure 7: Heating application: porous packed bed SHS system, reprinted/adapted with permission from Ref. [3], 2022, Springer Nature. structure and the working fluid, which results in a higher rate of heat transfer and, thereby, significantly improves the system thermal efficiency. [PERSON] et al. [51] conducted a numerical analysis of natural convection in a concentric horizontal annulus filled with a porous structure saturated by Cu-water nanofluid. It turned out that a low porosity (\(\epsilon<0.5\)) increases the thermal conductivity of the medium, and it has no effect on the flow of the fluid nor on the heat transfer. On the other hand, they found out that a large porosity (\(\epsilon>0.5\)) intensifies the convective flow. In 2015, [PERSON] et al. [52] numerically examined the thermal behavior of a square cavity composed of solid porous medium (_aluminum foam and glass beads_). They targeted the effects of pore morphological parameters such as porosity. The authors noted that the local and mean Nusselt numbers are minimum at high porosity, and the latter significantly affects the heat transfer rate. In 2014, [PERSON] et al. [53] proposed a porous unit designed to store sensible heat. They demonstrated that the use of a porous medium with high permeability and low thermophysical properties improves the performance of the considered TES unit and raises temperature and the stored sensible energy amount. [PERSON] et al. [54] discussed the influence of volcanic rock porosity and magma (SHSM). They indicated that an increase in porosity decreases the density and compressive strength of rocks while increasing their deformability. Thereby, they advised adopting a low porosity. [PERSON] et al. [55] conducted an experimental study of SHS performance of a vertical porous bed composed of glass beads and air which is heated with a constant heat flow.
## 3 Results
### Kopen-Geiger Biome Specific Analysis  
Global _p_-value significance maps were calculated for the ELV\(\rightarrow\)VPGC link. One exemplary _p_-value map is shown in Figure 2. Here, each of the five main biomes was analyzed to ascertain what fraction of the biome's area is susceptible to GC causality. These fractions are shown in Figure 4.  
SM\(\rightarrow\)LAI connections show a strong presence (>0.4) for arid, cold, and polar biomes. Moderate cover fractions describe other links, although SM \(\rightarrow\)NDVI causalities are relatively scarce (0.15) on polar biomes as compared to other VPs (>0.3). P, as expected, causes larger arid areas (>0.26) for all variables, with the largest cover fraction for P\(\rightarrow\)LAI (0.4). As compared to SM, P shows less effect on VPs over cold and polar climates, with all cover fractions being lower than 0.2. T shows low (\(\sim\)0.15-0.2), but constant, causal distribution amongst many VPs, with higher fractions for the NDVI in cold and temperate biomes (0.26 and 0.28). R-caused VPs cover nearly half of the cold and polar biomes, with moderate fractions over the other three climate zones. R\(\rightarrow\)NDVI appears to be less causal in polar regions, being merely half of the cover fraction, as suggested by other ELV\(\rightarrow\)VP links in the same setting.  
The results for causation links obtained in Section 3.1 were further analyzed by dividing the globe into different biomes and investigating the statistics of the _p_-values and F statistic GC cases. Each F statistic global map was masked and the corresponding biome of interest's statistical metrics were calculated accordingly. Figure 5 shows the biome-wise distribution of the GC F statistics for each ELV\(\rightarrow\)VP link. One important note to consider is the non-exclusivity of causality from different ELVs. In other words, one pixel can be caused by both, e.g., precipitation and temperature; these are further assessed by the F statistics, and the maps for the primary causal variables are shown in Figure 6. The main findings from the boxplot's statistical metrics are described as follows. Water availability exhibits the greatest influence on the LAI; SM\(\rightarrow\)LAI is a prominent causal link on arid, cold, and polar biomes, and P\(\rightarrow\)LAI is also a strong link on arid biomes, similar to those investigated in Figure 4. R poses a substantial causal effect for all VPs on cold and polar biomes, whereas it does not show such consistent driving forces on other biomes.  
Figure 3: Global distribution of F statistic for each ELV \(\rightarrow\)VP link.  
Figure 4: Fractions of G-Caused area of the given biome to the whole biome’s area.  
Figure 5: _Cont_.
## 2 Spectrum Sharing Processes
### Negotiation  
Spectrum access is subject to negotiations among competing groups. Negotiations can be carried out in a fully distributed and localized manner (e.g., among neighbor groups [18]), at regular intervals, or when the need to reallocate spectrum emerges. This is the case, e.g., when a new wireless Access Point (AP) is set up in an area where existing entities have already come to an agreed upon spectrum allocation scheme. Different forms of negotiations are possible. Simple mechanisms rely on the broadcast of fixed policies, while interactive mechanisms require bi-directional communication, but enrich possible features.  
Negotiation can take place in a centralized or decentralized fashion. Centralized mechanisms [19, 20] require significant bandwidth around the point of decision to bring in the information. Challenges arise in dealing with incomplete or outdated information. In decentralized approaches [21, 22], local and up-to-date information is usually available, but delays can defer global synchronization.  
Another issue pertains to the control channel [23]. In order to be robust against malicious behavior, the control channel must be out-of-band. In order to ensure the availability of such a channel, it can be exclusively assigned to a channel owner, who is in charge of the resource. A single control channel must be shared by multiple parties and can therefore be subject to attacks.  
Many frameworks for negotiation protocols have been proposed, also in other contexts (e.g., Web services). Such a protocol must also consider the trust relationships between the participants. Imported information from untrusted sources can enable an attacker to alter resource allocation.  
The resource allocation must cope with the physical limitations of the stations. Allocating resources is an optimization process which takes into account, among other things, parameters such as the capacity demands of the senders, the transmission distance and noise based on local knowledge about sources of interference. The signal-to-noise ratio at the receiver should be included in the decision making for resource allocations.
## 3 Experimental Analysis  
The experimental MLS point cloud data used for deformation analysis were collected during two key measurement sessions in 2023. The first session, conducted in March 2023, and the second session, held in September 2023, was conducted six months later, allowing for the monitoring of any significant deformation or structural changes over the intervening period.  
The direction of movement of the railcar sensor platform during both measurement sessions followed the orientation along the tunnel's length. Specifically, the railcar moved in the north-south direction of Guangzhou Metro Line 1, from East Railway Station (north) to Huadiwan Station (south), covering an underground distance of approximately 15.85 km. Guangzhou Metro Line 1 is a circular tunnel with an outer diameter of 7.13 m, an inner diameter of 5.4 m, a ring width of 1.2 m, and an absolute elevation of buried depth at the top of \(-9.90--10.45\) m. The scan range mileage covered 102 shield rings, spanning approximately 122 m, and represented our experimental area. A 2 km/h scanning speed, 100 lines/s, was used.
## 1 Introduction  
Colorectal cancer (CRC) is the third most common cancer and the second leading cause of death worldwide. Almost 20% of such patients will develop metastatic disease, about one-third of patients already present with liver metastases at the time of diagnosis [1,2]. Alongside traditional imaging (e.g., ultrasonography, CT, MRI), [18]FJDG PET/CT is routinely used as a tool for accurate staging and restaging after therapy in patients with colorectal metastatic disease, and it represents a valuable ally for risk assessment, prognosis evaluation, and treatment strategy decisions making.  
Radiomics is that part of artificial intelligence (AI) that aims to provide quantitative characteristics (features) from biomedical images of different nature that cannot be assessed by the human eye, assuming that any smallest image's constituent (i.e., voxel and/or pixel) may encompass features of tumor's phenotypes that may be potentially related to tumor's outcome and patients' response to therapy, reflecting the pathophysiological process and supporting medical decisions. The workflow of radiomics' processes can be simply resumed in five main steps starting with the acquisition of images, pre-processing tasks (registration, deconvolution, denoising, and so on) and VOI delineation, features extraction, reduction, and selection, and finally, the selection of the predictive model using AI-based classifiers [3]. In the last decade, the use of radiomics in the study of medical images has aroused increasing interest [4,5]. Several studies have demonstrated the correlation between the heterogeneity of the tissues and the radiomics features, which would allow obtaining relevant information through the analysis of the images alone [6].  
[18]FJDG PET/CT could be a useful modality for assessing tumor viability and differential diagnosis also for colorectal metastatic cancer and may provide important data regarding the appropriate treatment strategy [7,8]. The further integration of [18]FJDG PET/CT data with radiomics features could reach the provision of new insightful information also regarding tumor biology. In other words, the statistical analysis of the features using methods of increasing complexity (first order, second order, or higher) can be useful in the prognostic evaluation, in therapeutic management, and in characterizing tumor phenotypes [9]. Radiomics' literature in colorectal cancer is highly limited in PET imaging, but it nonetheless holds promise for genetic mutation status assessment [10,11] and the prediction of outcomes.  
The present study aimed to investigate the potential application of texture analysis on restaging [18]FJDG PET/CT images in metastatic colorectal patients, proposing a radiomics model able to select PET and CT imaging features for global disease status prediction, liver metastasis evaluation, and survival outcomes.
## 2 Framework Design of Gateway  
As a solution to the monitoring system problems described above, we designed an embedded gateway with an automatic back-up mechanism. The gateway gathers data from each sensor node in the monitored area and then transmits the data to the remote server as shown in Figure 2. As mentioned above, we define priority levels for communication channels. The highest level is \"USB\" communication. The second is communicating over \"Ethernet\". The lowest priority level is \"GSM/SMS\" live data communication. When the gateway receives sensor data from the Zigbee Coordinator, the data will be transmitted to the monitoring server according to the preset transmission priority level. In addition, the priority levels for communication channels can be adjusted from the monitoring server by the user, so as to adapt to different types of transmission application scenarios.
# A High-Efficiency Method of Mobile Positioning Based on Commercial Vehicle Operation Data
## 2 Cellular-Based Positioning Methods  
The 3 rd Generation Partnership Project (3 GPP) defined three classes of cellular-based positioning methods: the assisted global position system (A-GPS), mobile scan report (MSR)-based location methods, and database lookup methods [9].
## 4 Related Works  
This section provides a detailed analysis of recent the state of the art (SOTA), as presented in Table 4.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  
The work of [PERSON], [PERSON] et al. [17] explores key challenges and advancements in integrating 5G cellular networks with the IoT, particularly in the context of UDNs. It highlights the role of AI-driven optimization techniques, ML models, and big data analytics in enhancing network efficiency, resource allocation, and security. This study reviews existing approaches to energy-efficient communication, intelligent traffic management, and real-time data processing while addressing critical concerns such as latency, scalability, and interoperability. In addition, it examines the impact of wireless power transfer and cooperative energy-sharing methods in terms of sustaining network operations. Despite significant progress, unresolved issues such as security vulnerabilities, high computational costs, and limited training data for AI models remain. This paper contributes to this evolving field by proposing a framework that balances network performance, energy efficiency, and security, paving the way for more resilient and adaptive UDN architectures in future wireless communication systems. [PERSON] et al. [5] analyzed the role of UDNs in addressing the growing demand for high-capacity and low-latency wireless communication. Their work highlights the significance of small-cell types, including femtocells, picocells, and microcells, in enhancing network coverage, spectral efficiency, and user experience. By deploying a dense network of small cells, UDNs effectively mitigate congestion but introduce challenges such as interference management, resource allocation, and energy efficiency. This paper reviews various techniques, including coordinated multipoint transmission, interference cancelation, and ML-based optimization, to overcome these challenges. Furthermore, it discusses the distinct advantages of different small-cell types in network densification, considering factors such as coverage area, power consumption, and user capacity. Recent advancements in hybrid network architectures and self-organizing capabilities have also been explored to improve the scalability and adaptability of UDNs. The findings contribute to ongoing research on optimizing small-cell deployments for future wireless networks. [PERSON] et al. [18] examined the evolution of UDNs as a pivotal solution for enhancing wireless communication efficiency. It explores the integration of small-cell types, such as femtocells, picocells, and microcells, to improve the network capacity, coverage, and spectral efficiency. This study highlights the primary challenges associated with UDNs,
## 4 Proposed Model of SACFIR and SAMCFIR  
In this section, we propose two routing protocols called SDN-based Application-aware Centralized adaptive Iterative Flow Reconfiguring (SACFIR) and its extended version, SAMCFIR. The proposed models are designed for centralized intelligent path selection for OpenFlow-enabled sensor nodes assisted by the SDN central controller residing at BS. The proposed model's route computation at the SDN controller is periodic. This enables resource-awareness and application-sensitivity, allowing us to obtain feasible flow reconfiguration solutions. Flow reconfigurations take time and cause small disturbances that affect the QoS. The proposed protocols compute a feasible solution in every iteration, but the optimal path selection solution is reinstalled every 10 th round to avoid redundant reconfiguration operational cost. The SDN controller sets the computational formula of the default reconfiguration threshold for the current period, which is calculated as:  
\[RT_{q}=\left\{\begin{array}{ll}\frac{T_{v}}{(1-T_{v}\times(qmod\frac{1}{T_{ v}})},&\text{if }rE>0\\ 0,&\text{otherwise}\end{array}\right. \tag{11}\]  
where \(RT_{q}\) is the threshold value, \(T_{v}\) is the desired percentage of the threshold value, with the default value of \(T_{v}=0.1\), while qis the current period and \(rE>0\) indicates the residual energy of alive nodes. This method achieves the major objective of the proposed protocols, which is to implement re-installation of the configurations with minimum cost by holding back the re-computed paths for a certain period. However, in certain situations when networks face a drastic performance decline and if the current period \(Min-cost^{OPT}_{q}\) is much lower than previous period \(Min-cost^{OPT}_{q-1}\), then the proposed models reset the current period value \(q=9\). In this case, the SDN central controller considers the current iteration as the 10 th period and performs an abrupt reconfiguration execution. The periodic route computation of the SDN controller executes the SACFIR and SAMCFIR routing algorithms,in which every round consists of three phases called the Network Topology Management Phase (NTMP), the Network Settling Phase (NSP) and the Network Forwarding Phase (NFP). The SACFIR and SAMCFIR routing algorithms share a similar procedure to NTMP and NSP, while the major differences are seen with respect to NFS. The details of the next three sub-sections provide the technical depth of the proposed models.
# ULYSSES: Automated FreqUentLY ASked QueStions for KnowlEdge GraphS
###### Abstract  
The exponential growth of Knowledge Graphs necessitates effective and efficient methods for their exploration and understanding. Frequently Asked Questions (FAQ) is a service that typically presents a list of questions and answers related to a specific topic, and which is intended to help people understand that topic. Although FAQ has already shown its value on large websites and is widely used, to the best of our knowledge it has not yet been exploited for Knowledge Graphs. In this paper, we present ULYSSES, the first system for automatically constructing FAQ lists for large Knowledge Graphs. Our method consists of three key steps. First, we select the most frequent queries by exploiting the available query logs. Next, we answer the selected queries, using the original graph. Finally, we construct textual descriptions of both the queries and the corresponding answers, exploring state-of-the-art transformer models, i.e., ChatGPT 3.5 and Gemini 1.5 Pro. We evaluate the results of each model, using a human-constructed FAQ list, contributing a unique dataset to the domain and showing the benefits of our approach.  
Keywords:RDF knowledge graphs; large language models; frequently asked questions +
Footnote †: journal: Applied Sciences
# Advancing C-V2X for Level 5 Autonomous Driving from the Perspective of 3 GPP Standards
## 5 SA-Based 5G V2X Services
### Network Support
#### 5.2.2 Access Network  
The 3 GPP standardization has considered 5G radio frequencies as enablers for 5G-V2X communication. In this connection, various standard documents are reported and specified providing 5G-enabled access network support for V2X services. Including other network supports, two important RAN supports are reported for NR support and UE radio transmission and reception.  
The 5G new radio (5G-NR) is expected to provide support for the current aV2X use cases (as detailed in (_TR 22.186 Rel-15 and Rel-16_)) and new aV2X services. In this regard, the 3 GPP technical report (_TR 38.885 Rel-16_) investigates the 5G RAN aspects for advanced V2X services, including 5G sidelink (PC5) aspects, i.e., NR sidelink design, synchronization, resource allocation, and protocols; Uplink and downlink (Uu) aspects, i.e., aV2X use cases over Uu interfaces, and resource allocation/configuration; QoS management, i.e., model, profile, and parameters; RAT and interface selection, i.e., 4G and/or 5G RAT, UE upper layers select the radio interface; coexistence, i.e., between 4G and 5G V2X; networkaspects, i.e., authorization, slicing aspects, and resource coordination; and evaluations and measurement results.  
The core and access network part of 5 GS has been contributing to the realization of advanced V2X use cases available in _Rel-15_ and _Rel-16_. Though the UE policies in 5 GS cover the core network part, the UE radio transmission and reception for 5G-based V2X services are reported in the technical document (_TR 38.886 Rel-16_) for covering the 5G access network part. The reported radio solutions provide further 5G network support to the described aV2X services in the document (_TR 38.885 Rel-16_) [21]. Hence, the 3 GPP reported supports for V2X service are: 5G sidelink operations and QoS management; operating bands and channel arrangements; transmitter and receiver characteristics; and evaluation of channel and in-device coexistence. The available specifications and recommendations will help NR V2X operations and allow new radio frequency-based solutions from the relevant research community. The researchers are also encouraged to make use of radio frequency core requirements for 5G V2X operating scenarios and plan futuristic procedures for realizing 5G V2X services.
###### Abstract  
This work presented a comparison between two Voltage Controlled Oscillators (VCOs) designed in 65 nm CMOS technology. The first architecture based on a Ring Oscillator (RO) was designed using three Current Mode Logic (CML) stages connected in a loop, while the second one was based on an LC-tank resonator. This analysis aimed to choose a VCO architecture able to be integrated into a rad-hard Phase Locked Loop. It had to meet the requirements of the SpaceFibre protocol, which supports frequencies up to 6.25 GHz, for space applications. The full custom schematic and layout designs are shown, and Single Event Effect simulations results, performed with a double exponential current pulses generator, are presented in detail for both VCOs. Although the RO-VCO performances in terms of technology scaling and high-integration density were attractive, the simulations on the process variations demonstrated its inability to generate the target frequency in harsh operating conditions. Instead, the LC-VCO highlighted a lower influence through Process-Voltage-Temperature simulations on the oscillation frequency. Both architectures were biased with a supply voltage of 1.2 V. The achieved results for the second architecture analyzed were attractive to address the requirements of the new SpaceFibre aerospace standard.  
ring oscillator; LC-tank oscillator; SpaceFibre; rad-hard circuits; radiation effects; high-speed data transfer 2020