esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Results and Discussion
### Overall Performance of Odd/Even Evaluations and Low Sample Rate Effects
Figure 12 shows the overall success rates in identifying the firing TDC. For the three load points up to 0.5 kW, 100% was ensured; over this threshold, the percentage quickly dropped, as the sample rate did not ensure accurate results. Attempts were made to change the combination of the 1 st and 2 nd reference points, but results did not improve significantly. Nonetheless, given the fact that calculating the slope ensured good results for three out of the five load points with a 5-fold lower sampling rate could be an important advantage compared to the rpm method. Actual optimization of the sample rate with respect to rpm would also be an interesting line of development for the new method. One other advantage of the spark duration method is that it can provide additional information with respect to rpm. A previous study demonstrated the capability of evaluating in-cylinder flow velocity based on spark duration measurements [44], and even if it  
Figure 11: Illustration of sample rate effects on the points read during spark events. Figure 12: Success rate of firing TDC identification for the spark duration method in odd/even mode with two different sample rates. can be applied only at a single point in the combustion chamber, it can ensure a valuable background for improving combustion control margins.
# A VHF Circularly Polarized Turnstile Antenna with Balun for Meteor Radar
## 6 Conclusions  
A turnstile VHF circular polarized antenna has been designed and employed for meteor radar, utilizing a transmission line power divider and balun. A 1:1 unbalance-to-balance transformer has been implemented to enhance the radiation characteristics of the designed antenna. Considering the difficulties in radiation and gain testing, after fabricating and improving the antenna feeding network, a receiving antenna array is utilized in the meteor radar system. Better performances, such as increased meteor counts and improved azimuthal distribution of meteors, are achieved.  
**Author Contributions:** Methodology and investigation, W.Q.; data curation and writing--original draft preparation, W.Q. and M.L.; writing--review and editing, C.Z.; W.Y.; funding acquisition, C.Z. and Z.Z. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by the National Natural Science Foundation of China (NSFC grant No. 41574146, 41774162, 42004130, 42204161, 42104150), the fellowship of China Postdoctoral Science Foundation (2022M710941), the Foundation of National Key Laboratory of Electromagnetic Environment (Grant No. 6142403180204, 6142403200303), Chinese Academy of Sciences, Key Laboratory of Geospace Environment, University of Science and Technology of China (GE2020-01), and the Fundamental Research Funds for the Central Universities (2042021k0020).  
**Data Availability Statement:** The data presented in this study are openly available in [[https://zenodo.org/record/7821683#.ZDaqj3](https://zenodo.org/record/7821683#.ZDaqj3) ZBzEY]([https://zenodo.org/record/7821683#.ZDaqj3](https://zenodo.org/record/7821683#.ZDaqj3) ZBzEY), accessed on 14 March 2023.  
**Acknowledgments:** We acknowledge the use meteor radar dataset provided by Beijing National Observatory of Space Environment, Institute of Geology and Geophysics Chinese.  
**Conflicts of Interest:** The authors declare no conflict of interest.
# Research on High-Performance Fourier Transform Algorithms Based on the NPU
## 4 Methods
### The Direct Matrix Multiplication-Based DFT Algorithm (MM-2 DFT)  
As analyzed in Section 3.2, directly solving Formula (5) incurs a computational complexity of \(O(N^{2})\), making it impractical for most heterogeneous acceleration hardware, such as GPUs and FPGAs. This approach, however, holds engineering significance for NPUs equipped with dedicated matrix multiplication hardware units.  
The direct matrix multiplication algorithm (MM-2 DFT) solves Formula (5) using the cube units of the NPU directly. When using NPU cube units for computation, \(N\times N\) matrices can be decomposed into multiple \(16\times 16\) low-order matrices, and the block matrix multiplication method can be used to obtain the transform result of \(N\times N\) matrix results. This is what the NPU excels at, and it can fully use the cube units' computing power. Fortunately, most NPU platforms provide high-order matrix multiplication primitives, such as the general matrix multiplication (gemm) operator provided by the Huawei NPU platform. These NPU platforms are commonly used as coprocessors to execute the gemm operator. During execution, the CPU transfers raw data to the NPU platform, which performs the operator calculation and returns the results to the CPU.  
When the cube unit of the NPU performs matrix multiplication, it does not directly calculate complex numbers. Therefore, the real and imaginary parts of the DFT matrix need to be used as inputs for the MM-2 DFT algorithm. Then, using the properties of complex multiplication, the complex results can be calculated to obtain the desired output. The specific algorithm for MM-2 DFT is shown in Algorithm 1.  
To prevent the intermediate results from overflowing during the calculation process of the MM-2 DFT algorithm, it is necessary to normalize the input values of \(X\) beforehand. Afterward, the Fourier Transform is computed on all the \"rows\" of \(X\), then the result is transposed, and the Fourier Transform is applied to all the \"rows\" of the transposed result. Note that the \"rows\" of the transposed result actually correspond to the \"cols\" of the original matrix. After completing those two transformations, transposing the result yields the final result of the 2D Fourier Transform. During the calculation process, data copy operations can be parallelized in single-operator calculations like gemm, optimizing the overall algorithm execution time.
# Robot Localisation Using UHF-RFID Tags: A Kalman Smoother Approach +
## 3 Materials and Methods
### Signal Model  
RFID-based localisation systems comprise a set of RFID tags deployed at known locations inside a certain environment and an RFID reader that is able to read the backscattered signal. The phase delay of the RFID signal with \(2\pi\)-radian period can be stated as  
\[\phi_{i}=\frac{4\pi d_{i}}{\lambda}+\delta_{i}^{\phi}=\phi_{i}^{\prime}+2\pi N +\delta_{i}^{\phi}, \tag{3}\]  
where \(\lambda\) is the wavelength, \(d_{i}\) is the actual distance between the tag and the reader, and \(\delta_{i}^{\phi}\) is an offset due mainly to cables, reader and antenna components and transponder backscattering [28]. Moreover, \(\phi_{i}^{\prime}=\text{mod}(\phi_{i},2\pi)\) where \(N\) is the integer number of half-wavelengths within the distance \(d_{i}\). In practice, the unwrapped absolute phase \(\phi_{i}\) cannot be measured directly. Therefore, \(N\) is unknowable and the phased-based measured distance \(d_{i}^{m}\) is inherently ambiguous, i.e.,\[d_{i}^{m}=d_{i}+\delta_{i}^{d}=\frac{\phi_{i}^{\prime}}{4\pi}\lambda+\delta_{i}^{d}, \tag{4}\]  
where the uncertainty term \(\delta_{i}^{d}=N\frac{\lambda}{2}+\frac{\lambda}{4\pi}\delta_{i}^{d}\) in general can be very large, but it is also approximately constant for distance variations smaller than half wavelength. Therefore, since \(\delta_{i}^{d}\approx 0\) the variation in time of the relative distance between the RFID reader and the \(i\)-th tag tends to be insensitive to phase ambiguity and offset, and it can be written as  
\[d_{i}\ =\ d_{i}^{m}\ \approx\ \frac{\lambda}{4\pi}\phi_{i}, \tag{5}\]  
We denote the actual distance of the \(i\)-th tag at time \(kT_{s}\), where \(T_{s}\) is the sampling period of the RFID reader, as \(d_{i,k}\), i.e.,  
\[d_{i,k}=\sqrt{(X_{i}-x_{k})^{2}+(Y_{i}-y_{k})^{2}}, \tag{6}\]  
where \((X_{i},Y_{i})\) are the Cartesian coordinates of the RFID tag. Thus, the time derivative of the distance function (6) and using (4) is  
\[\dot{d}_{i,k}=\dot{d}_{i,k}^{m}=v_{k}\bigg{[}\frac{(x_{k}-X_{i})\cos(\theta_{ k})+(y_{k}-Y_{i})\sin(\theta_{k})}{d_{i}}\bigg{]}, \tag{7}\]  
which is the instantaneous variation of the distance at time \(kT_{s}\). Albeit (7) is inherently robust to the phase ambiguity, its validity is useful for localisation only locally, i.e., for displacements taking place in a neighbourhood of a known initial location [36]. The adoption of the EKF-RTS smoother proposed in this paper alleviates this issue by incorporating two consecutive robot positions, i.e., \(s_{k}\) and \(s_{k-1}\), in the filter state, as better shown later. As a consequence of this choice, the output function adopted is a straightforward discrete approximation of (7), i.e., a finite difference of the measured distances (4). More precisely, by denoting with \(d_{i,k}^{m}\) and \(d_{i,k}\) the measured and actual distances at time \(kT_{s}\) from the \(i\)-th tag, respectively, we have that the adopted output function for the \(i\)-th tag is  
\[h_{i}(s_{k},s_{k-1})=d_{i,k}^{m}-d_{i,k-1}^{m}=d_{i,k}-d_{i,k-1}. \tag{8}\]
## 3 Results and Discussion  
### Effects of Sub-Lethal Concentrations of NP/Derivatives on AF Production: A. flavus  
To investigate the effects of sub-lethal concentrations (Supplementary Figure S2a,b) of NP or their structural derivatives on AF production by _A. flavus_, NPs/derivatives were applied to _A. flavus_ at 0.1 to 1.0 mM, depending on types of compounds (Table 1). Most compounds marginally affected the growth of _A. flavus_ at the test concentrations, except SLD, which prevented fungal growth at 1.0 mM. Then, the level of AF production (AFB1, AFB2) at each concentration point was compared to that of control (no treatment; defined as 100%). AF production with an SD value \(\pm\) 4% was considered equivalent to the control in this study.  
As shown in Figure 2a, 20 out of 52 concentration points (marked as an upper arrow (\"\(\cdots\)\")) exhibited enhanced AF (B1, B2) production compared to the untreated control (9 to 129%). As mentioned earlier, _A. flavus_ produces AFB1 and AFB2 only, but not AFG1 and AFG2, whereas 2,4-D, 4I3M and 4-MOC did not enhance AF production at any concentrations examined. While CARV increased the AFB2 production at 0.2 mM (36% enhancement), both 4I3M and CARV at 0.4 mM showed the most potent anti-alfatoxigenic activity (81 to 97% inhibition), whereas the structural analog THY at 0.2 mM enhanced the AFB2 production at the highest level compared to other treatments (129% enhancement) (Order of AF inhibition (THY derivatives): 4I3M > CARV > THY; high to low).  
Noteworthy is that, although SLD and salicylic acid (SA) are very close structural analogs (viz., only one additional oxygen in SA structure compared to SLD), SLD at 1.0 mM completely prevented the growth of _A. flavus_, while SA allowed fungal growth along with AFB1 enhancement at the same concentration.  
Figure 2: Cont.
## 3 Results and Discussion
### Texture Analysis  
The phase symmetry results achieved from standard deviation of the magnetic RTP (RTP) (Figure 13A) were from the aeromagnetic survey. It illuminates the local structure, which allows detecting the ridges as well as valleys. Symmetry detection (RTP_STD_PS) (Figure 13B) classifies the parts of magnetic discontinuity such as lithological boundaries, faults, and dykes (positive and negative features), as well as thresholder (RTP_STD_PS_THRESH) and skeletonized (RTP_STD_PS_THRESH_SKEL) structures. The skeletal structures are investigated to crop a set of straight-line segments that will be fitted and computed. Figure 14A,B exemplify the structure contact density heat map (RTP_STD_PS_TRESH_SKEL_VEC_COD) and the orientation entropy map (RTP_STD_PS_TRESH_SKEL_VEC_OE) created by a set of intersections that include crossings, junctions, and corners of the spotted line segments [73]. The high prospective areas can be identified as the intercepted or deviated linear structure. The line segments are used to calculate the contact occurrence density (Figure 14A) and orientation entropy (Figure 14B).  
The lineaments which were extracted from the aborded approach presented in Figure 13A using the CET Grid Analysis tool of Geosoft Oasis Montaj are presented as extracted magnetic lineament overlaid on a standard deviation RTP map of the Bou Azzer inlier (Figure 13A). The rose diagram (Figure 15) of the obtained linear structures presents a dominant trend in the ENE-WSW direction, which agrees with previous work of [5; 13; 87; 88; 89; 90]. A less dense but significant lineament trend occurs in many directions with a region extending from 1 to 50 Km. The obtained results and inspection with magnetic RTP and geological map are summarized below:  
1. A good correlation between geological and magnetic structures was observed;
2. Contact between serpentine rocks and surrounding rocks could be considered as a prospective area for cobalt or associated mineralization;
3. The alignments of prospective areas had a dominant trend of NNE-SSW, NW-SE, NNW-SSE, E-W, and NE-SW directions;
4. The most prospective parts for cobalt, copper, and associated mineralizations are located on the zones with the high contact occurrence density and high orientation entropy in the Bou Azzer inlier and its surroundings.
## Communication protocol
### Mobile Network Infrastructure
#### 2.5.2 Radio Access Network  
LTE Base Station (4G): Evolved Node B  
The LTE base station Evolved Node B (eNB) provides all radio access functions via the air interface. The eNB manages the radio resources (Radio Resource Control (RRC), dynamic scheduling), takes care of the routing of user data to the SGW and operates the transmission of paging and broadcast messages via the air interface. Internet Protocol (IP) header compression and the encryption of user data are also functions that are covered by the base station. In addition, measurement reports on the channel quality are created. Furthermore, the eNB is responsible for selecting an MME for the User Equipment (UE) attachment, which is not specified by the terminal itself.  
Figure 5: Graphical User Interface (GUI) of the implemented reference application ATCAPp for the experimental UTM environment. A UAV (green dot with red outline) with callsign _us1_ is waiting at the reporting point _WHISKEY_ for ATC clearance to enter the controlled airspace _UniBv CTR_ (red area) and to continue its flight. White triangles indicate the next waypoints while the dashed line represents the route according to the filed flight plan.  
NR Base Station (5G): Next Generation Node B  
The Next Generation Node B (gNB) performs essentially identical functions as the eNB. However, it also offers new functionalities on the air interface such as Beamforming which increase data rates compared to the eNB. According to the standard, besides the Frequency Range 1 (FR1) below 6 GHz, the so-called millimeter waves above 20 GHz in the Frequency Range 2 (FR2) are also used. Due to the much larger bandwidth in FR2, higher data rates are possible compared to FR1.
# A Thermal Discomfort Index for Demand Response Control in Residential Water Heaters
## 4 The Proposed Approach for Defining a Discomfort Index
### Water Temperature Model
#### 4.3.2 Formulation  
The linear temperature model is applied to determine the values of coefficients \(c_{cool}\), \(c_{heat}\), and \(c_{use}\). The input data for the temperature model are the values of \(T_{min}\) and \(T_{max}\) and the information about on blocks and water utilization.  
The coefficients of the model are calculated as follows:  
* _Coefficient_\(c_{cool}\). First, two consecutive temperature recoveries are identified. Then, \(\Delta_{rec}\) is calculated as the time between the the end of the first recovery and the beginning of the next recovery. Finally, \(c_{cool}\) is calculated by Equation (1). The procedure is described in the left box of Figure 6. From the graphic, \(c_{cool}<0\). \[c_{cool}=\left(T_{min}-T_{max}\right)/\Delta_{rec}\] (1)
* _Coefficient_\(c_{heat}\). First, a recovery is identified and \(dur_{rec}\) is defined as its duration. Then, \(c_{heat}\) is computed by Equation (2). The procedure is described in the middle box of Figure 6. From the graphic, it is clear that \(c_{heat}>0\). \[c_{heat}=\left(T_{max}-T_{min}\right)/dur_{rec}\] (2)
* _Coefficient_\(c_{use}\). The first step is identifying a temperature recovery followed by a water utilization event. Then, \(T_{init}^{use}\) and \(T_{end}^{use}\) are defined as the temperature at the beginning and end of the utilization, respectively. To compute \(T_{init}^{use}\), the value of \(c_{cool}\) (already computed) is used as the slope to draw the line that passes through \(T_{max}\) at the end of the recovery, and intersects with the start of the utilization. Similarly, to compute \(T_{end}^{use}\), the value of \(c_{heat}\) (already computed) is used as the slope to draw the line that passes through the end of the on block associated with the utilization and intersects with the end of the utilization. \(dur_{use}\) is defined as the duration of the utilization. Finally, \(c_{use}\) is calculated by Equation (3). The procedure is described in the right box of Figure 6. \[c_{use}=\left(T_{end}^{use}-T_{init}^{use}\right)/dur_{use}\] (3)  
Figure 5: Linear temperature model.
## 3 Results and Discussion
### Chemical Properties of Dust and Soil Samples
Notably, sites such as S1, S3, and S18 exhibited high EC values, which reflect the accumulation of soluble salts. While the overall EC for most sites was within the normal range (below 2.00 dS m\({}^{-1}\)), as reported by [PERSON] and [PERSON] and [PERSON] (2018), several sites exhibited EC values that exceeded this threshold. For example, sites S1 (10.67 dS m\({}^{-1}\)), S3 (4.44 dS m\({}^{-1}\)), S13 (2.53 dS m\({}^{-1}\)), and S18 (7.78 dS m\({}^{-1}\)) showed signs of mild-to-severe soil salinity, indicating compromised soil quality. These high EC levels are likely due to factors such as anthropogenic (human) activities and water flow, as noted by [PERSON] and [PERSON] [PERSON] and [PERSON] (2018). Human activities such as intensive agriculture, industrial discharges, and urban development contribute significantly to soil salinization. Practices such as over-irrigation and the use of saline water for irrigation can lead to the accumulation of salts in the soil. The EC values in these sites surpass the acceptable limit of 2 dS m\({}^{-1}\) for most soil types, suggesting potential adverse effects on soil quality and fertility (Table 3). The wide range of EC values indicates varying levels of salinization across the sites. We have discussed the implications of high EC levels on soil quality and crop productivity, particularly in sites such as S1, S3, and S18. The concentrations of cations and anions have been examined to highlight their roles in soil fertility and potential environmental risks, particularly in relation toodicity. The concentration of sodium (Na\({}^{+}\)) was particularly high in sites S1, S18, and S3, indicating highodicity and poor soil structure in these areas. These findings align with the classification of many study sites as sodic soils, characterized by high concentrations of Na\({}^{+}\) ions. The presence of high sodium levels further corroborates the issues of soil permeability and fertility in these areas. High sodium content is commonly linked to reduced soil permeability and fertility, a relationship also emphasized by [PERSON] (2018). In soils with elevated sodium levels, such as those observed in this study, these effects can hinder water infiltration and root growth, ultimately compromising soil health and agricultural productivity. Additionally, chloride (Cl\({}^{-}\)) concentrations showed significant variability across the sites, with S1 exhibiting the highest levels. This suggests severe contamination that could negatively impact soil quality and agricultural productivity.
###### Abstract  
We propose and demonstrate a compact all-fiber laser generating cylindrical vector beam (CVB) using carbon nanotubes as the saturable absorber for mode-locking and a two-mode fiber Bragg grating (TM-FBG) as the mode discriminator. Both radially and azimuthally polarized beams with a polarization purity of 90% were obtained by simply adjusting the polarization controllers. The CVB mode-locked fiber laser operates at 1552.9 nm with a 3-dB line width of less than 0.02 nm, generating ns CVB pulses. The all-fiber CVB laser may have potential applications from fundamental research to practical applications, such as particle capture, high-resolution measurement and material processing.  
cylindrical vector beam; two-mode fiber Bragg grating; mode-locked fiber laser; carbon nanotube +
Footnote †: journal: Applied Sciences
## 5 Conclusions  
In this study, we fabricated and assessed the degradation of biomechanically comparable PLLGA 85:15 scaffolds in a simulated physiological degradation for 56 days and performed an in vitro study to assess the effect of degradation on cell viability for 28 days. Furthermore, an accelerated degradation was also incorporated to understand the suitability of the scaffolds for cartilage tissue engineering. The results revealed that PLLGA 85:15 scaffolds exhibited a stable degradation for 56 days in physiological conditions via surface degradation. The scaffold retained its structural and mechanical features over clinically relevant periods required for cartilage to regenerate in vivo. Additionally, the scaffolds supported cell proliferation and cell migration within the pores, which are critical parameters for tissue regeneration in vivo. Accelerated degradation performed on the scaffolds demonstrated a stable degradation in the scaffolds for 28 days without significant changes in the properties. This demonstrates the suitability of the PLLGA 85:15 scaffolds for cartilage tissue engineering. Future research will focus on long-term degradation effects on cell viability, characterising cellular differentiating capabilities on the PLLGA 85:15 scaffolds for cartilage tissue engineering applications in animal models, as well as tailoring a composite with a hydrogel to improve the formation of the extracellular matrix.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/polym15183714/s1](https://www.mdpi.com/article/10.3390/polym15183714/s1)]([https://www.mdpi.com/article/10.3390/polym15183714/s1](https://www.mdpi.com/article/10.3390/polym15183714/s1)), Table S1: Strand thickness changes with degradation at 37 \({}^{\circ}\)C; Table S2: Molecular weight of scaffolds during degradation at 47 \({}^{\circ}\)C; Table S3: Strand thickness changes with degradation at 47 \({}^{\circ}\)C; Table S4: Molecular weight of scaffolds during degradation at 47 \({}^{\circ}\)C.  
Conceptualization, K.M. and S.A.C.; methodology, investigation, writing--original draft preparation, A.G.D.; writing--review and editing, K.M., S.A.C. and E.L.; resources, E.L. and F.B. All authors have read and agreed to the published version of the manuscript.  
This work has been funded by the Engineering and Physical Sciences Research Council (EPSRC) via a Ph.D. Studentship (S3809 ASA+D9103 URO) and the Wellcome Trust (UNS40040).  
Ethical approval for cell collection was provided by the Office for Research Ethics Committees Northern Ireland (ORECNI ref: 18/NI/0174), and approval for continued use was given by the University's Faculty Research Ethics Committee.  
Data Availability Statement: Data is available from the corresponding author on request.  
Acknowledgments: Corbion Biomaterials, The Netherlands, is acknowledged for providing Poly(L-lactide-co-glycolide). The authors would like to thank [PERSON] for his assistance with the GPC measurements in this study.  
The authors declare no conflict of interest.