esa-sceva/satcom-chunk-collection huggingface dataset:
## 2 Theoretical Insight
### Qualitative Analysis  
From these observations, a negative stiffness system does not offer a stable operating regime. This is why a positive stiffness is introduced, which will have the role of sufficiently compensating this negative stiffness to ensure the stable operation of the system. The overall stiffness will then be quasi-zero but positive. The combination of these two stiffnesses of opposite signs gives the resonator great flexibility over the frequency range to be isolated, especially the low frequencies.  
As a preliminary qualitative analysis, a static perception may lead to the two following considerations. First, the mass is suspended by four identical folded beams providing the positive stiffness that is considered as four springs having individual stiffness \(k_{s}\). The equivalent positive stiffness \(k_{p}\) is evaluated from the dynamic balance as \(k_{p}=4k_{s}\). The bending stiffness of the folded beam is approximated by the equivalent stiffness of the cantilever beam as \(k_{s}=3E_{s}l_{s}/L_{s}^{3}\). This is later validated in Section 3.1. Second, since the supported-supported (S-S) and clamped-clamped (C-C) beam with load at midspan has an equivalent bending stiffness of \(k_{b}=48 EI/L^{3}\), respectively, \(k_{b}=129 EI/L^{3}\), the S-S or C-C beam with spring \(k_{p}\) at midspan has an equivalent stiffness of \(k_{cq}=k_{b}+k_{p}\). This qualitative analysis is used in the next sections to weight parameters and evaluate dynamic features.
# Field Tests on Eco-Friendly Railway Precast Concrete Slab
###### Abstract  
This study focuses on evaluating the field performance of a newly developed eco-friendly precast concrete slab track structure for railway/subway systems in Seoul, South Korea. Although Ballasted railway track structures are one of the most common track structures in the railway industry, they have some drawbacks including higher maintenance cost, un-uniform supports, and a high level of noise and vibration. However, a ballastless (slab-based) track structure system requires less maintenance and uniform support conditions, as well as several ballastless structure systems developed for high-speed trains. The Seoul Metro subway in South Korea has developed a ballastless reinforced concrete (RC) slab railway system using a type of conventional concrete. This study presents a ballastless precast concrete slab using a newly developed eco-friendly concrete, which can significantly improve structural performances and the manufacturability of a railway track structure system. This study evaluates the field performance of the eco-friendly concrete slab system deployed in one of the existing tunnel sections of the Seoul Metro subway system. A total of 10 m long slab sections including a 5 m long eco-friendly \"ballasted track to slab track (B2S)\" panels section and a 5 m long conventional B2S panels section are installed and monitored side by side. Field tests are performed to measure the level of noise, vibration, dynamic wheel load, rail displacement, and rail stress. The field measurements from the eco-friendly B2S section are compared to those of the conventional reinforced concrete slab track systems. The results show that the performance of the new B2S system using the eco-friendly concrete is comparable and/or superior to the conventional system.  
Eco-friendly concrete; ground granulated blast furnace (GGBF) slag; electric arc furnace (EAF) oxidizing slag; ballasted track to slab track (B2S) +
Footnote †: journal: Applied Sciences
# Design and Evaluation of IoT-Enabled Instrumentation for a Soil-Bentonite Slurry Trench Cutoff Wall
## 4 Data Transport
### XTP Extensions  
In the SB slurry wall deployment, we used XTP for point-to-point data transfer. The protocol is not limited to point-to-point data collection and could be used to transfer data from multiple data sources at a single receiver in a start topology. This would rely on the radio's underlying MAC protocol for collision avoidance. Typical MAC protocols are either scheduled or unscheduled. Unscheduled protocols use carrier sensing to detect other transmissions and use various algorithms to minimize collisions. Schedule protocols, such as TSMP [19], generate collision-free schedules for all nodes.  
Figure 9: Achieved data throughput transferring 1 MiB of random data between two XBee 802.15.4 series 1 radios with XTP and various chunk sizes over both good and poor quality links.  
XTP could be layered above both classes of MAC protocols to provide additional reliability when transferring large files. However, for best results, the MAC protocol should support the selection of both reliable and unreliable quality-of-service. XTP uses the MAC protocol's reliability mechanism for control messages and it's own reliability mechanism for data messages.  
For deployments over a larger distance, it might be necessary to construct a multi-hop network. A large number of ad-hoc network routing protocols exists that could be layered below XTP for network routing, such as RPL [20]. For a small number of hops, utilizing relay nodes could be another solution. In the simplest form, this would be a full node that first receives a file, buffers it, and then transmits the received file to the next host. This could be achieved without modification to XTP, however, this would increase the latency of the transfer. If this additional latency was unacceptable in the target application, the node could relay on a per-chunk or even per-fragment basis with minimal effort by developing an XTP-aware relay application.
# Online Phase Measurement Profilometry for a Fast-Moving Object
###### Abstract  
When the measured object is fast moving online, the captured deformed pattern may appear as motion blur, and some phase information will be lost. Therefore, the frame rate has to be improved by adjusting the image acquisition mode of the camera to adapt to a fast-moving object, but the resolution of the captured deformed pattern will be sacrificed. So a super-resolution image reconstruction method based on maximum a posteriori (MAP) estimation is adopted to obtain high-resolution deformed patterns, and in this way, the reconstructed high-resolution deformed patterns also have a good effect on noise suppression. Finally, all the reconstructed high-resolution equivalent phase shifting deformed patterns are used for online three-dimensional (3D) reconstruction. Experimental results prove the effectiveness of the proposed method. The proposed method has a good application prospect in high-precision and fast online 3D measurement.  
Keywords:phase measurement profilometry; super-resolution image reconstruction; online three-dimensional measurement; maximum a posteriori; random field +
Footnote †: journal: Applied sciences
# Concurrent Validity of the Inertial Measurement Unit _Vmaxpro_ in Vertical Jump Estimation
Once again, the presence of significant differences between the IMU and the criterion can be seen, indicating the presence of systematic error and highlighting the need for approach validation studies from different perspectives, not just the possible existence of correlation. It is worth noting that the validity of the _Vmaxpro_ has only been examined in studies that have assessed velocity in barbell-weighted jumps, and therefore the IMU is located in the barbell, further from the center of mass. In this sense, [PERSON] and [PERSON] [23] carried out a validation of _Vmaxpro_ against a linear position transducer using loads of 25, 50, and 75% of 1 RM (one-repetition maximum) in the squat to perform a loaded jump with a countermovement. They found strong correlations between the two devices (\(r=0.92\)-0.96) when studying the peak velocity from which the vertical height can be estimated. At the same time, all the data obtained were between the LoA in the Bland-Altman plots. However, a systematic error was shown in the plots (\(-0.12\) m/s), and significant differences were observed when performing a paired samples \(t\)-test (\(p<0.001\)). In a similar study performing countermovement jumps with a 50% 1 RM squat load, [PERSON] et al. [22] once again found strong correlation coefficients (\(r=0.92\)-0.99) and SEE values of 0.11 m/s when compared to MoCAP. Despite the manufacturer's claims that the _Vmaxpro_ can be used to estimate jump height [24], no validation studies have been identified that assess the accuracy of this device when used to measure countermovement jump (CMJ) or any other type of VJH using an accelerometer placed at the hip, as is common in sports science research. Additionally, no studies have examined the device's accuracy in measuring jumps performed without additional load, which is how most jumps related to technical actions in sports or daily life are performed. The lack of load in these jumps allows for a higher take-off velocity, making it suitable to validate the instrument within that speed range. Therefore, this study aimed to quantify the concurrent validity of the _Vmaxpro_ IMU compared to a 3D motion capture instrument considered a gold standard when estimating the VJH in CMJ execution.
# Reliable Internet of Things: Challenges and Future Trends
## 6 Future Opportunities and Challenges
### 6G Communications  
6G communications will be an important enabling technology for future IoT applications. By improving the communications in terms of achievable data rate, packet delivery ratio, and latency, reliable data dissemination between IoT nodes can be achieved. 6G will use terahertz communications, Reconfigurable Intelligent Surfaces (RIS), and massive computing to significantly improve the end-to-end communications between various IoT-enabled nodes.  
Terahertz communications can provide short-range high data rate connectivity between IoT nodes. Massive IoT applications will require increased data transmissions, and terahertz communications can be an ideal choice. However, challenges such as the connectivity range of terahertz for IoT need further investigation [145]. To further enhance the range of terahertz, techniques such as multi-hop communication can be used. Another potential technology to improve the range is reconfigurable intelligent surfaces that can intelligently reflect signals towards the destination [146]. Challenges such as RIS selection for an IoT transmitter-receiver pair and RIS phase shift optimization require further attention [147].  
Massive computing algorithms are also needed as part of 6G communications. In this regard, challenges such as placement of fog nodes, computational resource allocation, and task offloading ratios need to be designed. Moreover, other factors such as the energy of the fog nodes is a critical factor that needs to be considered.
## 6 Results and Discussion
### Training Costs of the Student Models  
The SKD and CEKD models differ significantly in terms of their training costs when considering the carbon emissions generated during the training process. We refer to the second-last columns of Tables 3 and 4 for the differences in carbon emissions between SKD and CEKD. Figure 7 further illustrates the CO\({}_{2}\) emissions plotted against the different confidence thresholds, providing a clear visualization of this trend. We found that the confidence-estimation based filtering method in a low-resource KD training task can reduce CO\({}_{2}\) emissions by up to 79.7% without any performance loss. Additionally, the last columns of Tables 3 and 4 show the time required to train the student models. It can be seen from the tables that the training time is significantly less when using the filtered data. We note that the same architecture was used for all of our student models; as a result, their inference speeds are identical.  
\begin{table}
\begin{tabular}{l l l l l l l l} \hline  & & **SacreBLEU** & **chrF** & **COMET** & **Train** & **CO\({}_{2}\)** & **TT** \\ \hline Baseline & IN22-Gen & 37.38 & 65.17 & 84.56 & - & - & - \\  & FLORES-200 & 31.05 & 60.62 & 83.72 & & & \\ \hline SDD+OPD & IN22-Gen & 38.70 & 66.10 & 84.90 & 376,260 & 1.08 & 4.5 \\  & FLORES-200 & 31.86 & 61.06 & 83.90 & & & \\ \hline FDD+OPD & IN22-Gen & 39.12 & 66.34 & 84.81 & 341,884 & 0.67 & 3.86 \\ (1 st Quartile) & FLORES-200 & 31.99 & 61.11 & 83.91 & & & \\ \hline FDD+OPD & IN22-Gen & 39.31 & 66.43 & 85.05 & 273,428 & 0.66 & 3.83 \\ (2 nd Quartile) & FLORES-200 & 32.19 & 61.31 & 84.01 & & & \\ \hline FDD+OPD & IN22-Gen & 39.19 & 66.40 & 85.09 & 237,647 & 0.61 & 3.5 \\ (3 rd Quartile) & FLORES-200 & 32.16 & 61.29 & 84.01 & & & \\ \hline \end{tabular}
\end{table}
Table 4: Performance of the fine-tuned NLLB-200-600M student model. SDD: Standard Distilled Data, FDD: Filtered Distilled Data, OPD: Original Parallel Data. CO\({}_{2}\) is calculated in KGs. TT is the training time calculated in hours. All student models used the same architecture and had identical size and memory usage.  
These findings are especially encouraging for TSPs, which often operate under resource constraints and are increasingly mindful of sustainability goals. By adopting confidence-guided knowledge distillation, TSPs can achieve high-quality translation models while substantially reducing the environmental impact of training.
# PerHelper: Helping Developers Make Better Decisions on Permission Uses in Android Apps
## 5 Evaluation
### Performance Overhead  
We also evaluated the execution performance of PerHelper. We selected six open-source apps with different sizes and measured the time cost of PerHelper to generate permission sets and detect unprotected API methods. When an app was just loaded into the IDE (cold start), it cost more time for PerHelper to run compared to when the app had been used in the IDE for a while (warm start). The reason was that the IDE would not load all the code when the app was first loaded. However, when the app was edited and viewed several times, the IDE would cache some snippets of code to gain better performances, which also made it faster for PerHelper to parse the code.  
The result is shown in Figure 4. The processing time of PerHelper was roughly proportional to the size of the app it attempted to analyze. For the cold start case, the time cost to complete all its tasks for an app with about 50K lines of code was about 6 s. As for the warm start case (which is a more common situation PerHelper), the performance was much better, with the cost for an app with about 10K lines of code requiring less than 1 s and the cost for an app with about 50K lines of code needing only less than 2 s. Compared to the time used to look up API documentation or search the Internet, PerHelper introduced acceptable overhead for developers.  
\begin{table}
\begin{tabular}{l l} \hline \hline
**Name** & **Unprotected API** \\ \hline RingsExtended & MediaPlayer\#setDataSource \\ \hline Android-SMSpopup & ActivityManager\#getRunningTasks \\ \hline Android-scripting & ActivityManager\#gerRunningServices \\ \hline Antiriplog & LocationManager.requestLocationUpdates \\ \hline Radar & LocationManager.requestLocationUpdates \\ \hline \hline \end{tabular}
\end{table}
Table 4: Examples of open-source apps with unprotected API methods.  
Figure 4: Execution time of PerHelper. The vertical axis denotes the time in milliseconds used to generate permission sets and detect unprotected API methods. The horizontal axis denotes the app name and lines of code.  
\begin{table}
\begin{tabular}{l c c c} \hline \hline
**Issue** & **\# of Apps** & **\# of Apps with the Issue** & **\% of Apps** \\ \hline Permission overprivilege & 97 & 22 & 22.7\% \\ \hline Permission underprivilege & 97 & 34 & 35.8\% \\ \hline Extra third-party permissions & 8 & 7 & 87.5\% \\ \hline Wrong permissions & 97 & 3 & 3.09\% \\ \hline Unprotected APIs & 97 & 21 & 21.6\% \\ \hline \hline \end{tabular}
\end{table}
Table 3: Permission-related issues detected in open source projects.
# Signal Quality Assessment for Transdermal Optical Wireless Communications under Pointing Errors +
###### Abstract  
In this paper, we assess the signal quality of the out-body to in-body optical communication link, which can be used as a fundamental enabler of novel biomedical appliances, such as medical implants, as well as biological and chemical components monitoring. In particular, we present a mathematical understanding of the transdermal system, which takes into account the optical channel characteristics, the integrated area limitations of the in-body unit, the transceivers' pointing errors and the particularities of the optical units. Moreover, to accommodate the propagation characteristics, we present a novel simplified, but accurate, transdermal path-gain model. Finally, we extract low-complexity closed-form expressions for the instantaneous and average signal to noise ratio of the transdermal optical link (TOL). Numerical and simulation results are provided for several insightful scenarios and reveal that pointing errors can significantly affect the reliability and effectiveness of the TOL; hence, it should be taken into account in the analysis and design of such systems.  
Keywords:optical wireless communications; pointing errors; transdermal optical wireless links +
Footnote †: _Technologies_**2018**, 6, 109; doi:10.3390/technologies6040109
## 2 Materials and Methods
### Capacitive Sensor  
Capacitive proximity sensors are devices that, without the need for contact, allow the detection of the presence or absence of practically any object regardless of the material (glass, paper, metal, plastic, biological, etc.). They use the electrical property called \"capacitance\", where by means of a change in the electric field produced by the object under observation (\"dielectric\"), it generates a change in the value of the resulting capacitance, thereby facilitating the detection of an object and the possibility of identifying the type of material that composes it [8]. Figure 1 shows the appearance of the capacitive sensor.  
When an object is located within the sensitive zone, an alteration of the electric field is produced, varying the resulting capacitance and therefore the frequency of the oscillator. There are two categories of targets that capacitive sensors can detect: the first is conductive and the second is non-conductive. Conductive targets include metal, water, blood, acids, bases, and salt water, among other similar materials. These targets have a higher capacitance and the dielectric strength of the targets is irrelevant [19]. When it comes to metallic elements, the electric field decreases since a phenomenon equivalent to series capacitances occurs.  
On the other hand, when dealing with a non-conductive target, it acts as an insulator for the electrode of the sensors. A target dielectric constant, also sometimes called a dielectric constant, is the measure of insulation properties used to determine the sensing distance reduction factor. For non-metallic objects, there is an increase in the electric field due to the increase in the dielectric constant. Capacitive sensors are normally used for the detection of non-metallic materials such as glass, oil, water, cardboard, ceramics, plastic, wood, and paper, among others [20].  
Although there are several very high-precision methods for measuring parameters related to magnetic permeability, electrical permittivity, and conductivity of a material, among which microwave measurement methods stand out, these are usually very expensive to implement in materials and equipment, which is why they are not considered suitable for the solution required for the problems associated with the identification of materials for the classification of waste at the source. Given this situation, it is considered feasible to carry out the classification process alternately, using a low-cost sensor, articulated with classification techniques-based machine learning algorithms.
# Drill Hole Orientation: Its Role and Importance on the Compression Response of Pure Magnesium
## 3 Results and Discussions
### Simulation Results
#### 3.1.2 Development of Plastic Zones
As the compressive load increases, the behaviour of vertical drill hole orientation is almost identical to the monolithic condition (no drill) albeit with a slightly larger plastic zone as shown in Figure 6. The horizontal and angular drill hole orientations also follow a remarkably similar plastic zone development pattern but also observe significantly higher plastic zone volumes at all loads when compared to vertical and monolithic (no drill) conditions. While angular drill hole orientation observes the highest plastic zone volume above critical strain till about 12,700 N, beyond that load, the horizontal drill hole orientation starts to observe higher plastic zone volume above critical strain. While this is counter-intuitive, an element to remember is that the development of these plastic zone volumes occurs in cylinders with different drill hole lengths. As detailed earlier in Section 2.1, the length of the drill hole in the angular drill hole orientation is approximately 9.94 mm, while that of the horizontal and vertical drill hole orientations is 8 mm. This detail is important as the plastic zone develops around the drill hole as these holes act as stress concentration regions. Hence, the plastic zone development can be better represented as a normalized plastic zone area by calculating the value of the plastic zone volume divided by the length of the drill hole. This is demonstrated in Figure 7a. A clear distinction can now be inferred on the load-bearing capacities of three drill hole orientations. From simulations, the first inference is that, at various loads, the vertical drill hole orientation provides better structural stability in compression when compared to angular and horizontal drill hole orientations, as it observes lower plastic zone volume above critical strain (Figure 6) as well as a smaller normalized plastic zone area over critical strain (Figure 7a). Figure 7b further illustrates this inference by showing how different the normalized plastic zone areas around the drill hole are at a 15,000 N compressive load. It is understood that the presence of larger plastic zone volumes above critical strain implies faster crack initiation/propagation around the drill hole leading to premature failure.