esa-sceva/satcom-chunk-collection huggingface dataset:
# Uncertainty in Automated Ontology Matching: Lessons from an Empirical Evaluation
## 5 Case Study: Spatio-Temporal Alignment of Indicators
### Experiment Description
The trimmed output alignment will only contain correspondences that have a confidence measure greater than or equal to the chosen threshold value. For alignment disambiguation, we apply an approach based on two major steps (Figure 2). First, we go through all the correspondences in the alignment, and we disambiguate each set of ambiguous correspondences having a source entity in common, as shown in Figure 1(a); then, we go through all the correspondences again, and we disambiguate each set of ambiguous correspondences having a target entity in common (coming from \(\mathcal{O}_{2}\)), as shown in Figure 1(b). In each step, disambiguation consists of keeping the strongest correspondence (i.e., the one with the highest similarity score) from the set of ambiguous correspondences and deleting the rest. If two ambiguous correspondences have exactly the same similarity score, we keep both of them. Finally, a reference alignment is manually provided by the authors for each target experiment for assessment purposes. Given an alignment to be evaluated and a reference alignment as input, the Alignment API [62] automatically returns the scores of the basic evaluation metrics (TP, TN, FP, and  
Figure 2: Alignment disambiguation—a simplified approach for the stable marriage model [63]. FN) as well as the scores of the advanced evaluation metrics (_Precision_, _Recall_, _F-measure_, _Overall_, _Noise_, and _Silence_), which reflect the quality of the input alignment. As for the ambiguity evaluation metric, we create a simple algorithm in Java that takes as input an alignment and returns the score of the _ambiguity degree_ metric, reflecting the ambiguity degree of that input alignment. Many applications that require the combination of multiple indicators are unlikely to be error-tolerant, meaning that the resulting alignment is expected to be entirely correct. Despite its relative simplicity, the case study proposed is relevant in different practical contexts and application domains. More concretely, the target case study is characterized by the need to compose indicators dynamically, and the resulting integration is expected to be precise and accurate. Practical examples may be identified, among others, in the areas of urban planning (e.g., [64]) and global sustainable development (e.g., [65]). Further requirements may characterize specific systems, such as real-time environments for disaster management [66].
## 8 Discussion
### Potential Regulatory Challenges  
Although the use of blockchain technology in agriculture has the potential to greatly improve supply chain traceability, efficacy, and trust, there may be regulatory obstacles. Decentralized systems provide a challenge to conventional hierarchies and structures, making it difficult for governments to create flexible and unambiguous regulatory frameworks. Important regulatory obstacles consist of:  
* _Data Access and Control:_ Regulators that tackle issues with data access and control may find it easier to impose laws. It becomes essential to strike a balance between promoting openness and safeguarding confidential information since agricultural data are sensitive. Finding this balance needs thought and attention in order to keep blockchain's benefits for traceability and trust intact.
* _Legitimacy of Smart Contracts:_ The use of smart contracts in agricultural operations presents a new regulatory obstacle. Legislative adaptation may be necessary to determine the legal validity and enforceability of smart contracts, particularly in areas with strict contract rules. To ensure that smart contracts are enforceable under the law, governments may need to set up frameworks that acknowledge the validity of contracts carried out via blockchain.
* _Interoperability Standards:_ As the use of blockchain technology spreads, interoperability may be hampered by the absence of uniform legal frameworks in many countries. The establishment of international standards that guarantee compliance with various regulatory contexts and enable the smooth integration of blockchain technology into the global agricultural supply chain may provide a challenge to governments.
* _Protection of consumers:_ Ensuring the security and legitimacy of agricultural goods is a major factor in the deployment of blockchain technology. Governments, nonetheless, need to create laws to protect the interests of consumers. In order to solve issues with misleading claims or misleading information, this entails establishing standards for labelling, certification, and quality assurance inside the blockchain.
* _Environmental Impact:_ Blockchain networks' energy usage, particularly for those that use proof-of-work consensus processes, has sparked worries about the environment. Governments may try to control how blockchain technology affects the environment in agriculture. This might have an influence on the consensus algorithms used and encourage the creation of blockchain solutions that are environmentally benign.  
The blockchain community, agricultural stakeholders, and regulatory agencies must work together to address these possible regulatory obstacles. Achieving compliance with legal and ethical norms while realizing the full potential of blockchain technology in agriculture will need the establishment of clear, flexible, and internationally harmonized regulatory frameworks. Our paper's examination of these issues seeks to further the current conversation around blockchain regulation in the agricultural industry.
###### Abstract  
Today, concepts within the Global Geodetic Observing System (GGOS) aim a Terrestrial Reference System (TRS) with 1 mm accuracy and long-term stability of 0.1 mm/year. GETRIS (Geodesy and Time Reference In Space) is a concept that aims to realize a relativistic reference system based on satellites as an extension to the TRS. This helps with another goal of the GGOS, namely, the connection of different satellite layers with the TRS. For a valuable contribution to the GGOS's goals, we would expect to achieve precise determined satellite orbits at the level of 1-3 mm and satellite clocks with a picosecond accuracy. The use of increasingly precise links helps to improve the satellite precise orbit determination (POD) and is necessary to synchronize the clocks in the satellite/station network. We analyze a complementary use of high-precision optical dual one-way links at the level of 1 mm precision together with the L-band. In previous studies, we analyzed the benefit for satellite POD, achieving Medium Earth Orbit (MEO) as well as geosynchronous orbit (GSO) accuracies at the low-millimeter level. In this work, we analyze the capabilities for clock synchronization. We compare two different clock types for estimation and prediction. We analyze different satellite constellations and different combinations of measurement links.  
GEO; IGSO; MEO; clock estimation; optical two-way link; inter-satellite link Article Toward a Geodesy and Time Reference in Space A Study of Apparent Satellite Clocks of a Future GNSS Satellite Constellation
## 2 Experimental Program
### Test Setup, Instrumentation, and Loading Procedure  
The test setup is presented in Figure 4. Each specimen was tested under a constant axial load and a cyclic lateral load during the experiment. The axial load was executed by a 2000-kN-capacity jack to a rigid steel load beam. The reversed horizontal load was transferred from a 1000-kN-capacity hydraulic actuator, which was aligned with the centerline of the load beam. The applied vertical and lateral loads were measured by a pressure sensor and the MTS electrohydraulic testing system, respectively. The foundation beam was anchored to the laboratory floor by anchor bolts to prevent slide and uplift of the base. To avoid out-of-plane displacement of the specimens, two parallel lateral bracings were installed perpendicular to the specimens.  
Figure 4 shows the external instrumentation of the specimens. The key displacements of the test walls were measured with a set of linear variable differential transformers. L1 was arranged to monitor the slide of the foundation, L2-L6 were placed along each specimen's height to acquire the lateral deflection of the wall during the experiment, and L7 and L8 were utilized to control the uplift of the foundation beam.  
Figure 5 shows the internal instrumentation of the specimens. The strain gauges were attached to the horizontal and vertical rebar of each specimen, at different locations, to investigate the stress of the reinforcement during the tests.  
A mixed force and displacement-controlled loading was adopted for the loading procedure in the test. One-cycle force-controlled loading was utilized at the elastic stage of the test walls, and two-cycle displacement-controlled loading was conducted at the plastic stage of the specimens, to fully develop the damage propagation. To obtain the post-peak behavior of the PRMSW, the tests were not terminated until the lateral strength of each specimen decreased to at least 65% of the experimentally recorded maximum capacity.  
Figure 4: Test setup and instrumentation for cyclic test: (**a**) Test setup; and (**b**) schematic diagram.  
Figure 5: The internal instrumentation for cyclic test: (**a**) Strain gauges of PMW-1 and PMW-2; (**b**) strain gauges of PMW-3A/B and PMW-4.
## 3 Channel Estimation in Different Frequency Bands
### Channel Estimation for RIS Systems in High Frequency Bands
#### 3.1.1 Channel Estimation for Fully-Passive RIS
Due to the passive characteristic of the RIS, setting up active elements in the passive RIS is necessary to estimate the channels of the BS-RIS and RIS-UE separately. In the next part of this section, the fully passive hardware architecture of the RIS changes to a semi-passive structure, and the corresponding channel estimation methods change.
## 2 Methodology
### Correlation between \(\Delta V_{RMS}\) and the Cell Capacity Fade \(\Delta C\)  
As explained, due to the impossibility of a direct measurement of the capacity fade \(\Delta C\) in practical charge-discharge cycles, this paper proposes an indirect measurement based on the indicator \(\Delta V_{RMS}\).  
Since the values of \(\Delta C\) and \(\Delta V_{RMS}\) are on different scales, they have to be normalized for a fair comparison. The min-max normalization is used for this purpose because it is one of the most commonly used methods to normalize data, which can be calculated as [32],  
\[x_{norm}=\frac{x-x_{\text{min}}}{x_{\text{max}}-x_{\text{min}}} \tag{7}\]  
where \(x\) is \(\Delta C\) or \(\Delta V_{RMS}\), and \(x_{\text{min}}\) and \(x_{\text{max}}\) are the minimum and maximum values of \(x\), respectively.  
\[\Delta C_{norm}=\frac{\Delta C_{n}-0}{0.3C_{rated}-0} \tag{8}\]  
\[\Delta V_{RMS,norm}=\frac{\Delta V_{RMS,n}-0}{(\Delta V_{RMS,n}-\Delta V_{ RMS,cut-off})-0} \tag{9}\]  
In this paper, the cell is considered to reach its end of life when \(C\) = 0.7 \(C_{rated}\); so, \(\Delta C_{end-of-life}\) = 0.3 \(C_{rated}\)[31]. \(\Delta V_{RMS,cut-off}\) is obtained from the manufacturer datasheet.  
However, the behavior and accuracy of \(\Delta V_{RMS}\) in quantifying the capacity fade needs to be evaluated. The Pearson correlation \(R\) is a useful statistic for this purpose. Figure 2 compares the behavior of the two indicators \(\Delta C\) and \(\Delta V_{RMS}\) for one of the cells analyzed, where a strong correlation is seen with \(R\) = 0.99. More details can be found in Section 4.  
Figure 1: Instantaneous terminal cell voltage [V] vs. SOC [p.u.] during the first discharge cycle (reference cycle) and the \(n\)-th cycle. Calculation of the \(\Delta V_{RMS}\) indicator between the first discharge cycle and the \(n\)-th (generic) cycle.
## 4 Conclusions  
In this study, an analytical modeling method was proposed to predict the molten pool dimensions in laser powder bed fusion additive manufacturing, with the consideration of process conditions-dependent absorptivity. The absorptivity under different process conditions were calculated by an empirical model of laser absorptivity. The temperature profiles in single tracks were calculated by a point moving heat source model with the laser absorptivity, material thermal properties, and process conditions as inputs. After comparing the predicted temperature distribution and melting temperature of the material, the molten pool dimensions were obtained. Ti6 Al4V was used as the material to validate the presented analytical method. The predictions of molten pool width and depth were compared to the experimental measurements of Ti6 Al4V. The predicted results show good agreement with the experimental data, which indicates the acceptable prediction accuracy of the presented model. In addition, the predicted results were compared against the predictions with constant absorptivity, which indicates that the consideration of different absorptivity can enhance the accuracy in the molten pool predictions. The computational time of the proposed method is less than 200 s, which is much less than that of FEM-based numerical methods. The sensitivity analysis shows that the molten pool with and depth have a nearly linear relationship with normalized enthalpy. The presented analytical method can predict acceptable results and save many computational resources, which makes it a potential tool for the study of molten pools and defects in LPBF.  
Conceptualization, W.W.; Data curation, W.W. and J.N.; Formal analysis, W.W.; Funding acquisition, H.G. and S.Y.L.; Investigation, W.W.; Methodology, W.W.; Project administration, H.G. and S.Y.L.; Resources, H.G. and S.Y.L.; Software, W.W. and J.N.; Supervision, H.G. and S.Y.L.; Validation, W.W.; Visualization, W.W. and J.N.; Writing--original draft, W.W.; Writing--review & editing, W.W., J.N., H.G. and S.Y.L. All authors have read and agreed to the published version of the manuscript. This research received no external funding.  
Not applicable.  
The authors declare no conflict of interest.
# Intelligent TCP Congestion Control Policy Optimization
## 4 Experiment
### Latency Sensitivity  
RTT represents the time it takes for a packet to be sent from sent to receive to acknowledged, reflecting the current network latency. Figure 5 shows a comparison of latency sensitivity, with the link bandwidth set to 700 Mbps, a queue of 1000 packets, and 0% random loss in our Mininet. When the link delay is less than 50 ms, the system latency of the traditional congestion control protocol is much higher than that of the intelligent congestion control strategy, indicating that TCP-PPO\({}_{2}\) can adapt to today's low-latency networks, thereby ensuring more efficient data transmission. When the link delay is higher than 90 ms, the delay of both is greatly reduced, but the delay of the intelligent system is still lower than the system delay of the TCP-CUBIC protocol.
## 2 Materials and Methods
### Create an Osteoclast Specific Dataset
#### 2.1.1 Culture of Human Monocytes and Osteoclasts  
Human monocytes were isolated from human buffy coats by density gradient centrifugation and subsequent magnetic cell sorting. Briefly, buffy coats diluted with PBS/EDTA/BSA (1:1) were centrifuged in leukocyte tubes containing Ficoll-Paque PREMIUM 1.073 g/L (GE Healthcare, Munich, Germany) to obtain the PBMC fraction. PBMCs were collected and further purified using an additional density gradient of 1.063 g/mL (PAN-Biotech, Aidenbach, Germany) to remove platelets. Finally, the mononuclear cells were washed with PBS/EDTA/BSA, and the non-monocytes were magnetically labelled using negative selection with a monocyte isolation kit II according to the manufacturer's instructions (Miltenyi, Bergisch Gladbach, Germany). The monocytes obtained were collected and seeded at a density of 250,000 monocytes/cm\({}^{2}\). Alpha mem with 7.5% heat-inactivated fetal calf serum (FCS) and 7.5% human serum, as well as 1% penicillin/streptomycin and 1% L-glutamine, were used in the basic medium. In addition, 25 ng/mL M-CSF (bio-techne, Minneapolis, MN, USA) and 25 ng/mL RANKL (bio-techne, Minneapolis, MN, USA) were added to the basic medium to induce osteoclast differentiation. The medium was changed every 2-3 days.
# Simulation and Design of Three 5G Antennas
## 4 Metal Frame Mobile Terminal Dual-Element \"Loop-Groove\" MIMO Antenna Design
### The Dual-Element \"Loop-Groove\" MIMO Antenna Design Process
#### 4.2.1 Design and Simulation of the Loop Antenna  
First, we designed a loop antenna operating at 3.5 GHz. We created a rectangular slot on the ground plane to form the circular architecture of the loop antenna. To mitigate the interference of the metal frame with the antenna's performance, we chose to design a slot in the metal frame and treat the metal boundary as part of the antenna's feeding structure [26]. Additionally, we designed a rectangular feeding branch, with its ends connected to the rectangular slot on the ground plane and the metal frame to effectively excite the loop antenna. Figure 28 illustrates the schematic diagram of the loop antenna structure.  
Figure 27: Signal strength with the installation of a metal phone case.  
In balanced mode, the ground currents between antennas can be effectively suppressed, leading to improved MIMO antenna isolation [27]. For this reason, the loop antenna's perimeter is chosen to be approximately \(\lambda\) and, given that width W = 0.012\(\lambda_{3.5\text{GHz}}\) = 1 mm, the length L of the loop antenna can be calculated as L \(\approx\lambda/2-\text{W}\approx\) 40.6 mm.  
The gap width in the metal frame is another critical factor affecting antenna performance. As shown in Figure 29, the curve illustrates the change in the loop antenna's S parameters as the gap width in the metal frame increases from 0.5 mm to 1.5 mm.  
From Figure 29, it can be observed that, as the gap width in the metal frame gradually increases, the isolation of the loop antenna remains around \(-10\) dB. However, the resonance frequency of the antenna tends to shift to the right, resulting in improved impedance matching and an expanded operating bandwidth. This is because, as the metal frame widens, the radiation of electric field energy becomes more convenient, optimizing antenna performance. Nevertheless, considering the aesthetics of mobile terminals, the gap width should not be excessively large. After considering various factors, a gap width of 1 mm was ultimately chosen, achieving high isolation for the loop antenna while integrating the metal frame as part of the antenna.
# Investigation of Segmented Halbach Array Design for Passive Magnetorheological Brake System
## 3 Segmented Halbach Array Design  
### Configuration Variations  
The proposed Halbach array design utilizes a strategic arrangement of Nd-Fe-B permanent magnets, aligned to create a concentrated magnetic flux adaptable to cylindrical configurations. This permanent-magnet segmented Halbach structure consists of a magnet array divided into discrete sections, each comprising a specific number of magnets. One segment can be stationary, contributing to maintaining a stable magnetic field, and the other is an adjustable segment that can move or change positions relative to the stationary magnets to dynamically alter the magnetic flux density. In the cylindrical configuration of a segmented Halbach array, '\(r\)', the inner radius, refers to the distance from the center to the inner edge of the magnets, as shown in Figure 4, that determines the location of the magnets relative to the axis of the cylinder and influences the distribution and strength of the magnetic field produced by the array. In this arrangement, the stationary segment consists of larger magnets 20 mm in length each. The adjustable segment consists of a magnet array configured with specific dimensions, and their positions can be altered to create a unidirectional magnetic field, as shown in Figure 5.  
The configuration of a Halbach array can be fine-tuned using three main parameters, as shown in Table 2. The length of the smaller magnets (\(L\)) defines the size of the smaller magnets relative to the larger ones in the array. Adjusting \(L\) impacts the strength and uniformity of the generated magnetic field, influencing braking torque. The gap width  
Figure 4: Proposed design of segmented Halbach array in cylindrical configuration.  
Figure 3: Conventional permanent-magnet Halbach array in a cylindrical configuration.  
between magnets (\(W\)), the distance between adjacent magnets in the array, determines the interaction strength between the magnetic segments. A larger gap reduces magnetic coupling, while a smaller gap enhances it, directly affecting the field intensity and flux linkage. The position of smaller magnets (\(P_{1}\) and \(P_{2}\)) relative to the center of the larger magnet axis describes the relative positioning of the smaller magnets along the axis of the larger magnets. Adjusting this parameter can modulate the overall symmetry and field distribution to target specific operational requirements. Effective design relies on precise magnet placement, alignment with the magnetorheological fluid (MRF) gap, and advantage in the array design, ensuring that the adjustable track complements the stationary track's field. Adjusting these parameters allows for a highly customizable Halbach array design that is adaptable to varied applications where the available space is restricted.
## 4 NMPC Formulation
### Warm-Start Initialization  
To improve computational efficiency and solver convergence, a warm-start initialization strategy is employed for selected NMPC configurations (CW, PW, IW). At each control interval at time \(t\), the optimal solution from the previous time step \(t-1\) is used as the initial guess for the current optimization problem. The solution horizon shifted forward by one step, and the last value was duplicated to maintain horizon length.  
Formally, if the previous solution was:  
\[U_{t-1}^{*}=\left[u^{*}(t-1),\ldots,u^{*}\big{(}t-1+N_{p}-1\big{)}\right] \tag{10}\]  
then the warm start at time \(t\) is constructed as, denoted with a superscript (0):  
\[U_{t}^{(0)}=\left[u^{*}(t),\ldots,u^{*}\big{(}t+N_{p}-2\big{)},u^{*}\big{(}t+N _{p}-2\big{)}\right] \tag{11}\]  
This warm-start mechanism preserves the temporal structure of the control sequence and has been shown to substantially reduce solver iterations and computation time, particularly in scenarios with slow system dynamics or small setpoint changes. In this study, both cold-start and warm-start options are systematically compared across all disturbance-handling strategies to assess their impacts on computational and control performance.
# Analysis of Satellite Compass Error's Spectrum
## 2 Materials and Methods
### Conducted Experiments  
In this paper, two kinds of experiments are reported: stationary and dynamic. During the stationary part of experiments, all the antennas were situated on a building roof or bench in a suburban area. The second part of tests was conducted using an automotive vehicle driven directly out of the urban area; however, the horizon was partially by trees. In addition, we used the part of our previous experiments conducted in Gdansk on tramway routes and published in [22] when the surprisingly low accuracy of the Furuno compass was observed. We intended to verify how significant the influence of the surroundings was on the observed errors in that investigation.