esa-sceva/satcom-chunk-collection huggingface dataset:
## 5 Conclusions  
Based on the traditional bowtie structure, two methods of introduction of the stubs have been presented to decrease the impedance of traditional bowtie antennas from hundreds to tens of ohms. A prepared JJ mixer with the \(R_{\text{n}}\) of 1 \(\Omega\) coupled with a pair of open-end stubs on the bowtie antenna has shown up to 88 harmonics with the conversion efficiency of \(-69.6\) dB. Coupled with traditional antennas, the JJ mixer with bowtie antenna pairing has achieved the highest harmonics. Moreover, the maximum harmonic number of 88 from the superconducting JJ mixer is more than four times higher than the harmonic number of 20 from the semiconducting Schottky diode mixer. The superconducting JJ mixer has the potential to be applied in an ultrasensitive THz receiver for future THz communications.  
As the series JJ structure has become another research interest to solve the problem of impedance mismatch between the mixer and the coupling antenna, the impedance of the mixer can be enhanced by cascading multiple JJs, so as to match the traditional antennas. Further work can focus on the integration of the bowtie traveling wave antenna and series JJ mixer. The work in this paper provides a reference and comparison for the future series JJ mixer coupled with the traditional bowtie antenna.  
Conceptualization, M.Y., C.L. and J.S.; data curation, M.Y., T.-L.L. and J.-X.S.; formal analysis, M.Y. and X.G.; funding acquisition, M.Y., C.L. and W.X.; investigation, M.Y., T.-L.L. and J.S.; methodology, M.Y. and Z.W.; project administration, M.Y., C.L. and W.X.; resources, M.Y. and W.X.; software, M.Y. and X.G.; supervision, M.Y. and W.X.; validation, M.Y. and W.X.; visualization, M.Y. and X.G.; writing--original draft, M.Y. and Z.W.; writing--review and editing, Z.W. and W.X. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China under grant numbers of 62001235 and 62104117, the Innovation Program for Quantum Science and Technology under the grant number of 2021 ZD0301701.  
Not applicable.  
The data presented in this study are available on request from the corresponding author.  
We thank [PERSON] and [PERSON] for their kind suggestions.  
The authors declare no conflict of interest.  
Figure 7: (**a**) Model of the actual mixer chip attached to a Si hyper-hemispherical lens in CST MWS. (**b**) Simulated input impedances where HTS JJs locate in (**a**) model.
## 3 SOM and WSN  
Self organizing maps (SOM), also known as Kohonen networks, are an unsupervised type of neural networks [32]. As in neural networks, the basic idea of SOM has origins in certain brain operations, specifically in projection of multidimensional inputs to one-dimensional or two-dimensional neuronal structures on cortex. For example, perception of color depends on three different light receptors (red, green and blue), plus the eyes capture information about the position, size or texture of objects. It has been demonstrated that this multidimensional signal is processed by the planar cortex structure. Further, it has been demonstrated that the areas of the brain responsible for different signals from the body preserve topology, e.g., the area responsible for the signals that come from the arms is close to the area responsible for the signals that come from the hand. These are precisely the basic ideas of SOM that consist in the following:  
1. Multidimensional data and their dependencies are presented and captured in a lower dimension SOM network (usually 2D).
2. The proximity of the nodes in SOM reflects similarity of the data mapped to the nodes.  
For these reasons, SOMs have been widely deployed for clustering and good visualization of the problem (Figure 1). They have been successfully deployed in different fields such as image processing [33], robotics [34] (for both visual and motor functions), network security [35], detection of outliers in data [36], etc.  
In this work we rely on SOM's ability for detecting outliers [36]. When compared with standard density estimation methods (as kernel density estimator), SOMs are relatively fast and inexpensive when the dimensionality of the data is large. Furthermore, SOMs do not significantly depend on the underlying data model and have no restrictions concerning data dimensionality. This is very important in our case, as we will see in the following text the dimensionality of our data model is variable and grow to be very high.
## 4 Analysis of Numerical Results
### Distilled Water Resonator
Moreover, the BW values for the LPA inverted and hollow inverted trapezoidal prisms are the highest and comparable to the patch antenna without a resonator, as presented in Table 4. Concerning the radiation pattern, depicted in Figure 7b and detailed in Table 4, the LPA hollow inverted and inverted trapezoidal prisms, followed by the VPA inverted trapezoidal prism and trapezoidal prism, exhibit significant improvements in terms of MLM. Note that all these geometries achieve reductions in terms of HPBW, with the LPA trapezoidal prism, hollow inverted, and inverted trapezoidal prisms achieving the highest reductions in this order. Most of the trapezoidal prism-based geometries also present reductions in SLL, particularly the LPA inverted trapezoidal prism. These characteristics lead to enhanced directionality and improved efficiency. Overall, the analysis of the different geometric shapes for the DW resonator reveals notable differences in performance. The cap-based and trapezoidal prism-based geometries are capable of achieving multiple resonant frequencies. Additionally, LPA half-cylinder shapes and trapezoidal prism-based geometries show potential for reducing the patch antenna size. Analyzing the results at the resonant frequency, Table 4, cone-based geometries exhibit the best performance. Regarding BW, the cylindrical hemisphere exhibits the highest value, followed by rectangular prism and cone. Regarding radiation pattern, the inverted cone achieves the most significant improvement in terms of MLM, along with substantial reductions in HPBW and SLL, which enhance the directionality of the patch antenna. Similarly, the LPA hollow inverted and inverted trapezoidal prism geometries exhibit comparable improvements, reinforcing their suitability for efficient and directional antenna designs. For consistency across the tables, 'w/o' is used to denote 'without', meaning that the parameter is either not applicable or was not detected in the evaluated scenarios.
# Design and Implementation of a Tether-Powered Hexacopter for Long Endurance Missions
## 2 Design and Analysis
### Hexacopter  
The hexacopter subsystem is built with off-the-shelf components listed in Table 2. Its airframe has 2000 g weight and it has the ability to carry a 1500 g payload because the heavy battery is omitted. The payload of the following experiments is an action camera (Hero3+, GoPro) with 170 g weight. Its mission is to periodically take videos/photos of the target site which will later be turned into a time-lapse video. The payload module can be changed to others according to mission needs.  
Instead of being powered by a large battery, the hexacopter is powered by a 600 W custom-built DC-DC converter (based on LTC3871, Analog Devices) which receives high voltage from the tether and delivers a controlled constant 24 V to every component on the hexacopter. The details of the DC-DC converter, including its topology, efficiency, and the feedback control circuit are supplemented in Appendix B.  
As shown in Figure 2a, an aluminum heatsink and two fans dissipate the heat generated by the DC-DC converter. Figure 2b is the thermal image of the DC-DC convertor providing 30 A at 24 V. The hottest region occurs at the location of high side MOSFETs at 86.8 \({}^{\circ}\)C, which is within their safe range.  
Figure 1: (a) System diagram of Tether-powered hexacopter; (b) Photos of hexacopter and ground station.  
A 36 Wh battery serves as a backup power which provides around 4 min of flight-time to land the hexacopter safely in case of emergency due the malfunction of the power supply chain. This backup battery is pre-charged to 24.1 V and then directly parallel-connected to the DC bus, which is internally controlled at 24 V. After turning on the system, the backup battery gradually discharges to 24 V and then always stays with the DC bus in the following. The experimental data show that the DC bus voltage runs between 23 to 24 V, which will not damage the battery.
## 4 Development of the Numerical Model
### Boundary Conditions and Burner Characteristics  
Regarding the domain boundary conditions, the lateral and upper surfaces were defined as \"Open boundaries\" using the simulation software's predefined function, as detailed in the user manual [44]. This approach allows for natural air circulation within the domain, preventing constraints imposed by physical boundaries and eliminating the need to expand the domain size. At the time of the experiment, wind speed was negligible; thus, it was set to 0 m/s in the simulation, representing calm atmospheric conditions. The open boundaries method is widely recognized and used in CFD research, effectively and accurately simulating the upper air volume. This approach aligns with methodologies employed in other studies [45; 46] and was validated by matching the environmental parameters to those of the real experiment. The simulation results demonstrated insensitivity to minor variations in these conditions, confirming the realism and robustness of the chosen settings.  
In the entire simulation domain, the following environmental parameters were defined as follows:  
* Initial oxygen concentration was set to 20.8%;
* Indoor temperature in the building was set to 20 \({}^{\circ}\)C;
* Initial carbon dioxide concentration was set to 0.04%;
* Initial visibility, at all points, was set to 30 m;
* Atmospheric pressure was set to 101,325 Pa.  
Inside the experimental stand, thermocouples were added at the same coordinates as shown in Figures 3 and 4. In addition to temperature, the HRR value of the entire fire source was monitored. Numerical values of temperatures and HRR will be compared with experimentally obtained data for the purpose of calibrating the numerical model.  
The composition of the fire source, the maximum HRR value per unit area, and the simplified HRR evolution curve were derived using the same two methods specified in the references [27; 47], providing detailed guidelines for these procedures [24].  
The combustion reaction in FDS requires that the combustible material be represented by a predefined and widely recognized chemical model consisting of four elements, with proportions C 3.4, H 6.2, O 2.5, and N 0 [30]. This model is well-established in the literature and has been validated using the PyroSim software developer's calculator [42]. It focuses on simulating a single material and is known for accurately replicating real combustion reactions, particularly for wood, ensuring precise and feasible results while enhancing computational efficiency. This approach has been supported by various references [48; 49; 50; 51; 52].
# Transmission Reduction for UV and IR Radiation with Dyed Lyocell Knitted Textiles
## Materials and Methods
### Dyes and Dye Processes  
#### 2.2.1 Preparation of Dye Solution  
Dye solutions of Remazol Brilliant Red F3B (Dystar, Raunheim, Germany) (monoazo, vinyl sulfone) (reactive dye), Drimaren Yellow HF-CD (Achroma, Wiesbaden, Germany) (monoazo, trifluorpyrimidine+vinyl sulfone) (reactive dye), Sirius Orange (Dystar, Germany) (disazo) (direct dye) and Solophenyl Bordeaux 3 BLE (Huntsman, Deggendorf, Germany) (disazo) (direct dye) were prepared in different concentrations with distilled water. The mentioned dyes were selected mainly for two reasons. First, the used Lyocell fibers exhibit a cellulosic chemical structure. Typical for dyeing of cellulose fibers are direct dyes and reactive dyes, because with these dyes the fiber dye interaction is strong to lead to sufficient washing and rubbing fastness. Direct dyes are used, because of simple application. Reactive dyes are known for the best washing stability after application on cellulosic fibers. For this, it is reasonable to evaluate both direct and reactive dyes. Second, the optical properties of used dyes are checked on their aqueous solutions by transmission measurements. If for them a decrease in transmission for near-infrared light is determined, these dyes are selected for further dyeing experiments. The dyestuffs are used as received from the supplier without further purification. For each dyestuff, two different concentrations are chosen for application on the textile fabric to present a sufficient proof-of-concept that by application of these dyes, the transmission of UV and infrared radiation can be reduced.
# Optimisation of Segregation Distances between Electric Cable Bundles Embedded in a Structure
## 5 Application to a Realistic Test-Case
### Description of the Use-Case under Study  
We considered in the article the reference test-case schemed in Figure 3. It has the following EM characteristics:  
* Bundle \(A\) is made of \(n_{A}=12\) elementary conductors and bundle B of \(n_{B}=24\) elementary conductors;
* The two bundles were parallel with each other and had the same length;
* All conductors of both bundles were loaded by a 9 \(\Omega\) common mode resistance at both extremities;
* A 115 V voltage generator, constant over the frequency range \(F=[f_{min},f_{max}]\), was applied on all elementary conductors of bundle \(A\);
* The susceptibility level of all conductors of bundle \(B\) was adjusted in \(F\) to obtain an optimised segregation distance \(d_{opt}\) between both bundles of about 15 cm.  
This use-case is reasonably balanced in terms of the representativity of real industrial cases and the computing resources needed to calculate the G function defined in Equation (1).  
Figure 3: Analysis of the EMC between bundle \(A\) and bundle \(B\).  
Figure 2: Implementation of the COBYLA/Kriging algorithm.  
Consequently, the objective is to compute \(d_{opt}\), for heights of bundles varying between 1.5 cm and 20 cm and a bundle length varying between 6 m and 15 m. This optimum distance should ensure that the probability to be susceptible is lower than \(\alpha=0.05\).  
In order to demonstrate the mathematical challenge of this use-case, the current induced on one elementary conductor of bundle B and computed by the CRIPTE computer code [4] is plotted versus frequency in Figure 4 for two very close installation configurations:  
* \(d=0.49\) m, \(h_{A}=9.2\) cm, \(h_{B}=4.5\) cm, \(l=53\) m;
* \(d=0.49\) m, \(h_{A}=8.7\) cm, \(h_{B}=4.0\) cm, \(l=52.8\) m.  
Figure 4 clearly illustrates the fact that below the resonance frequencies, the current response varies slowly with the installation parameters (distance, heights, and length), and the strategy of optimisation, including the surrogate model, will easily converge. On the contrary, in the domain of the resonance frequencies, we can expect a slow convergence and the need to switch from the surrogate model to the standard Monte Carlo method.
## 4 Industry Perception Study
### Feedback about Ability of DePaaS to Address SDP Challenges
#### 4.3.2 Solving SDP Problems Related to Datasets  
The sample pool was briefed about SDP problems related to datasets used in SDP and was asked whether DePaaS could help solve those problems.  
According to responses of software practitioners, DePaaS promotes use of industry datasets (53% positive, \(\chi^{2}\) = 9.80, CV = 3.84, \(\alpha\) = 0.05, \(p\) = 0.0017) since it would serve as a unified platform or a single place where commercial datasets could be shared for the common good of software defect prediction and prevention. About 69% of practitioners indicated that DePaaS could enforce and ensure data cleanliness as well (\(\chi^{2}\) = 7.54, CV = 3.84, \(\alpha\) = 0.05, \(p\) = 0.0060). This can be achieved by introducing data cleanliness as an entry criterion for the dataset being uploaded to DePaaS. About 57% software practitioners indicated that DePaaS could help enforcing a uniform or a standardized way of documenting defect data--however, this belief was not found to be statistically significant (\(\chi^{2}\) = 1.20, CV = 3.84, \(\alpha\) = 0.05, \(p\) = 0.2733). Most of the software practitioners (68%) were inconclusive about whether DePaaS would help addressing the problem of imbalanced datasets (\(\chi^{2}\) = 5.44, CV = 3.84, \(\alpha\) = 0.05, \(p\) = 0.0.19).
## 7 Discussion  
Microwave and millimeter-wave links continue to support the mobile anyhaul networks both for the legacy and the new 5G radio access points. Site densification and new fiber-optical aggregation points result in shorter hop lengths for the \(\mu\)/mmW links. In the coming years, a mesh topology composed of fiber-optical, FSO, and \(\mu\)/mmW radio links will be used with load sharing and route diversity techniques. In the radio hops adaptive modulation, ATPC and channel aggregation techniques support higher bit rates. New millimeter-wave frequency bands will receive emphasis thanks to the wide spectrum available. In the millimetric E and V bands, multi-Gbps links can support 5G deployments with high bit rates and low latency.  
In this paper, hop-length recommendations were given for the digital \(\mu\)/mmW radio links. Using the ITU recommendations for rain and atmospheric attenuation, a detailed fade margin and availability calculation method was presented. The presented calculation method takes antenna size, link frequency, polarization, and modulation mode into account. Example radio link calculations were shown with typical system gain and antenna size values. During the numerical calculations, rainfall rate statistics were considered that are typical in Central and Eastern European countries. Recommended hop length was plotted as a function of rainfall rate for the different frequency bands, link polarizations, and dish sizes. The calculated charts provide useful help in the planning, optimization and monitoring of \(\mu\)/mmW links.  
Finally, it was shown with rain-rate maps that, even in medium- or small-size countries, there may be significant rainfall rate differences in Europe. For more accurate availability and optimal hop-length calculations, locally collected meteorological data should be utilized in the radio link planning tools. As a result, the new links can be planned with the required availability targets, and the existing access network can be optimized to support the increased capacity demands of 5G deployments.  
The author thanks his current and former colleagues for the fruitful discussions and for the valuable support: [PERSON], [PERSON], [PERSON], and [PERSON] (Nokia Software and Nokia Mobile  
Figure 19: Rainfall maps of Norway measured over a long period. (**a**) Rainfall rates in mm/h, exceeded 0.001% of the time. (**b**) Rainfall rates in mm/h, exceeded 0.01% of the time. (**c**) Rainfall rates in mm/h, exceeded 0.1% of the time. Reproduced with permission from the Norwegian Meteorological Institute [54].  
Networks), [PERSON], [PERSON], [PERSON], and [PERSON] (BME, the Budapest University of Technology and Economics), [PERSON] (HIF, the Hungarian Communications Authority and TKI, the Research Institute for Telecommunications), [PERSON] (TKI and Ericsson), and [PERSON] (T2-Com Ltd.). All personal communications and valuable comments given by [PERSON], TMC Global, Australia and [PERSON], Southampton University, UK are highly appreciated. The author acknowledges ETSI, ITU, MetNo and RACOM for providing approvals and for their quick support.  
The authors declare no conflicts of interest.
# An Experimental Study on D2D Route Selection Mechanism in 5G Scenarios
## 2 Background
#### 2.1.5g  
5G networks consist of heterogeneous network cells (i.e., MC and \(fc\)) and nodes with different kinds of characteristics and capabilities, including transmission power and use of frequency bands.  
In Figure 1, a 5G network with control and data planes is shown. The MC BS in the control plane receives network-wide information, including changes of the routes and node availability [4; 17], from the CC. The MC BS communicates with a higher transmission power in lower frequency bands, and so it covers a larger area with more \(fc\) BSs and nodes, including the source node in the _data plane_. On the contrary, the \(fc\) BSs and nodes in the data plane communicates with a lower transmission power in higher frequency bands since they are in close proximity. Nodes can communicate via D2D [18], and so a \(fc\) source node \(fc_{s}\) can communicate with a \(fc\) destination node \(fc_{d}\), which is located out of its transmission range, in multiple hops.  
Although there are similarities between our 5G-based testbed and traditional networks, such as wireless sensor networks (WSN), particularly in the use of D2D routes, there are four main differences. Firstly, a source node must switch its route when PUs' activitiesreappear in the operating route in our testbed, while there is lack of PUs' activities in WSNs [19]. Secondly, the source node sends a single video stream to a destination node in our testbed, while sensor nodes send many packets to the sink node whenever an event is detected in WSNs [20]. Thirdly, there are heterogeneous routes, including D2D routes and the backbone route, and the D2D routes offload traffic from the backbone route in our testbed. However, there are homogeneous routes (i.e., D2D routes) only in WSNs. In other words, a source node can choose either next-hop node or the MC BS in our testbed, but a source node must choose a next-hop sensor node in WSNs [21]. Fourthly, our investigation focuses network performance, such as end-to-end delay and packet delivery ratio measurements, with a minimal focus on energy efficiency, which is the key performance measure in WSNs [22].
# Combined Optimization of Maintenance Works and Crews in Railway Networks
## 3 Methodological Framework and Problem Formulation
### Decision Variables  
* \(X_{alt}\)--indicates whether activity \(a\in A\) on link \(l\in L\) is assigned to time \(t\in T\), or not;
* \(M_{ll}\)--denotes whether period \(t\in T\) is used for preventive maintenance work, or not;
* \(Y_{kpl}\)--indicates whether the execution of project \(p\in PA\) starts at time \(t\in T\) on link \(l\in L\) if option \(k\in K\) is chosen, or not;
* \(B_{kpl}\)--indicates whether the execution of project \(p\in PA\) on link \(l\in L\) is conducted according to option \(k\in K\), or not.  
A decision variable \(h_{ealt}\) was added to our enhanced model for a scheduled task to be performed by a crew. The decision variable is binary and is a prerequisite for the improvement of decisions in the implementation of a task by a particular work crew. If a decision is made not to carry out a task on a particular link by a crew at a given time, the decision variable will be denoted as 0. Conversely, if the value is set to 1, it signifies that the crew is required to execute the task on that link. The decision variable added to the enhanced formulation problem is given below:  
* \(h_{ealt}\)--binary, indicating whether work crew \(e\in E\) serves link \(l\in LL\) at time \(t\in T\) for task \(a\in A\), or not.