esa-sceva/satcom-chunk-collection huggingface dataset:
# Q8S: Emulation of Heterogeneous Kubernetes Clusters Using QEMU
###### Abstract  
Kubernetes has emerged as the industry standard for container orchestration in cloud environments, with its scheduler dynamically placing container instances across cluster nodes based on predefined rules and algorithms. Various efforts have been made to extend and improve upon the Kubernetes scheduler. However, as the majority of Kubernetes clusters operate on homogeneous hardware, most scheduling algorithms are also only developed for homogeneous systems. Heterogeneous infrastructures, which include IoT devices or specialized hardware, have become more widespread and require specialized tuning to optimize workload assignment, for which researchers and developers working on scheduling systems require access to heterogeneous hardware for development and testing; such data may not be available. While simulations such as CloudSim or K8 sSim can provide insights, the level of detail they can offer to validate new schedulers is limited, as they are only simulations. To address this, we introduce Q8S, a tool for emulating heterogeneous Kubernetes clusters including x86_64 and ARM64 architectures on OpenStack using QEMU. Emulations created through Q8S provide a higher level of detail than simulations and can be used to train machine learning scheduling algorithms. By providing an environment capable of executing real workloads, Q8S enables researchers and developers to test and refine their scheduling algorithms, ultimately leading to more efficient and effective heterogeneous cluster management. We release our implementation of Q8S as open source.  
Kubernetes; emulation; heterogeneous; QEMU; OpenStack; scheduling +
Footnote †: journal: _Algorithms_  
0000-0001-5000-0001-5000][PERSON]
# Hierarchical Gradient Similarity Based Video Quality Assessment Metric
## 2 Hierarchical Video Quality Assessment
### Modeling of the Precortical Processing  
The precortical processing stage in the area LGN has a band-pass filtering characteristic for luminance stimuli [14]. This can be modeled by a denoising operation. A recent study [11] showed that perceptual distortion can be classified into content-dependent distortion and content-independent distortion. Content-independent distortion is mainly related to the additive noise. Thus, using the denoising operation, both the reference and distorted frames are decoupled into two parts: the _prediction part_ and the _noise part_. In this paper, block-matching and 3D filtering algorithm (VBM3D) [17] is employed for denoising. Furthermore, since MSE presents a good match with the additive noise [18], the MSE is adopted to evaluate the degradation of the noise part:  
\[S_{noi}(\mathbf{N}_{r},\mathbf{N}_{t})=1-\frac{\log_{10}(1+\text{MSE}(\mathbf{ N}_{r},\mathbf{N}_{t}))}{\log_{10}(255^{2})}, \tag{1}\]  
where \(\mathbf{N}_{r}\) and \(\mathbf{N}_{t}\) are the noise part of the reference and test videos, respectively; \(\text{MSE}(\mathbf{N}_{r},\mathbf{N}_{t})\) denotes the MSE between \(\mathbf{N}_{r}\) and \(\mathbf{N}_{t}\). The denominator \(\log_{10}(255^{2})\) is used to normalize the metric into the range [0,1]. In the numerator, adding 1 is to avoid to be smaller than 0. A \(S_{noi}\) approximately equal to 1 means the distortion is more weak.
## 3 WebAssembly and IoT
### WebAssembly and IoT Networking  
IoT systems are often characterized by networks of devices communicating with each other. Wasm's compact binary format can reduce the load on these networks and increase their efficiency. This section discusses the role of Wasm in IoT networking and how it can support efficient communication in IoT systems. With its cross-platform compatibility, security features, and performance efficiency, Wasm is well-positioned to support networking in IoT applications. This section discusses the role and implications of Wasm in IoT networking.  
* **Cross-platform Communication** One of the challenges in IoT networking is the heterogeneous nature of IoT devices. They can have different operating systems, architectures, and capabilities. Wasm, with its cross-platform nature, can help to bridge these differences. Regardless of the device's specific hardware or operating system, a Wasm module can run on any device with a compliant Wasm runtime. This provides a common platform that can facilitate communication and data exchange across diverse devices.
* **Efficient Data Transfer** Wasm's compact binary format facilitates efficient execution while contributing to efficient data transfer. Compared to traditional text-based code, Wasm's binary format is smaller and quicker to load, which can result in less network usage and faster transfer speeds. This is particularly important in IoT networks, which can involve the transfer of large amounts of data.
* **Secure Communication*
* Security is a paramount concern in IoT networks due to the potentially sensitive nature of the data being transferred. Wasm contributes to secure communication in number of ways:
* Wasm operates within a sandboxed environment, meaning that it is isolated from the rest of the system, helping to contain any potential security threats.
* Wasm is designed to be integrated with existing web platform security mechanisms, meaning that it can leverage features such as HTTPS for secure data transfer.
* **Real-time Communication** Many IoT applications require real-time or near-real-time communication. Whether a security system detecting an intruder or a health monitor tracking a patient's vitals, quick and responsive communication can be critical. Wasm's efficient execution and fast parsing can help to facilitate this kind of real-time communication.
* **WebAssembly Networking in Real-world IoT Applications** Wasm's networking features are being leveraged in various IoT applications. For instance, in the realm of smart home devices Wasm can facilitate efficient and secure communication between devices, including lighting systems, thermostats, and security cameras. In industrial IoT, Wasm can enable real-time monitoring and control of equipment across a network.
# Precoder and Decoder Co-Designs for Radar and Communication Spectrum Sharing +
## 5 Conclusions  
This paper considered the problem of interference management and alignment in radar and communication coexistence and spectrum sharing scenarios. A generalized multicarrier signal model for coexistence was proposed. The model provides an easy way to model, generate and analyze a multicarrier signal. A max-SINR joint precoder-decoder joint design based on IA theory was proposed. The design was formulated as a constrained optimization problem. By employing IA theory, the benefit of achieving the total DoF upper bound can be obtained. A distributed algorithm for finding the precoder and decoder was derived as a solution to a constrained optimization problem. This takes advantage of channel reciprocity.  
The proposed design allows for achieving better interference management between communication and radar nodes in comparison to the SSSVSP precoder design. The simulation results demonstrated that our algorithm significantly improved the total SINR for all radar and communication nodes and provided a significantly higher target-detection probability in a radar subsystem at a given constraint on a false alarm probability level while making the communication system almost interference free. The total SINR increased as a function of the SNR and the number of users while avoiding performance degradation.  
Conceptualization, Y.C. and V.K.; Formal analysis, Y.C.; Funding acquisition, X.J.; Methodology, Y.C. and V.K.; Project administration, Y.C. and X.J.; Resources, Y.C.; Software, Y.C.; Writing--review & editing, Y.C. and V.K. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Chinese Scholarship Council.
## 5 Computational Experiments  
Multiple sets of instances are found in the literature to test the algorithms designed to solve the LRP [74; 75; 76]. Nevertheless, these sets do not consider characteristics such as parameters uncertainty and flexible facility sizes, i.e., instances must be adapted to our problem's features. Therefore, we use Akca's [74] instances and introduce the following modifications:  
1. Traditional LRP instances consider that a single fixed size is available to assign to open depots. We extend this unit set to five alternative sizes, so that our algorithm selects one of them for each open depot. If \(s_{j}\) is the size proposed by the original instance for each potential depot \(j\in J\), and \(L\) is the set of available sizes, our approach' alternative sizes are \(s_{jl}\in\{(1-2r)s_{j},(1-r)s_{j},s_{j},(1+r)s_{j},(1+2r)s_{j}\}\), where \(l\in L\), \(0.0<r<0.5\), and \(r\) is the range of difference between available sizes. When \(r=0\), the case is the same as the traditional LRP. We consider that \(r=0.25\).
2. Traditional LRP instances consider a fixed cost (\(f_{j}\)) incurred whenever a depot \(j\in J\) is open. We keep this parameter unaltered. Additionally, we introduce a variable cost (\(o_{jl}\)) depending on \(f_{j}\) and \(s_{jl}\), namely: \(o_{jl}=\dfrac{(s_{jl}-s_{j})}{2s_{j}}\dfrac{\sum_{j}f_{j}}{|J|}\). This formula preserves \(o_{jl}\) in the same order as \(f_{j}\) for each depot \(j\in J\). Besides, it yields negative costs whenever \(s_{jl}<s_{j}\), positive costs whenever \(s_{jl}>s_{j}\), and a null cost when \(s_{jl}=s_{j}\). Thus our results can be compared with those found in the LRP literature.
3. An uncertain demand \(D_{i}\) for each customer \(i\in I\) is considered. The demand of half of the customers is assumed to follow a log-normal probability distribution. If \(\phi_{i}\) is the deterministic demand in the Akca's set, then \(E[D_{i}]=\phi_{i}\). In addition, three different values of variance are considered: low, medium and high, i.e., for \(\lambda\in\{0.05,0.10,0.20\}\)\(Var[D_{i}]=\lambda\phi_{i}\). These variability values are preserved identical to the ones used by [PERSON] et al. (2013), in order to perform a suitable results comparison. The demand of the other half of the customers is considered to be fuzzy. In this case, \(D_{i}\) can be estimated as low (DL), medium (DM) or high (DH). The demand in each of these fuzzy sets is represented by a triangular fuzzy number \(D_{i}=(d_{1i},d_{2i},d_{3i})\). If \(q\) is the vehicle total load capacity, all fuzzy demand values are expressed as a proportion of \(q\) in order to perform an appropriate comparison between the demand and the vehicle available capacity, i.e., \(0\leq D_{i}\leq 1\). The membership function of these fuzzy sets are displayed in Figure 2.
## 7 Conclusions and Future Work  
In this work, we pointed out the advantage of using S-transform to access to the frequency content of the ECG signals and localize the existent pace pulses, as well as the benefit of using Shannon energy to correctly detect even low-amplitude pace pulses. The performance of the designed algorithm is high (Se-100% and PPV-98%), when evaluated over a large database that includes various combinations of ECG arrhythmias and pace pulses with different amplitudes, rising edge and total pulse durations, as well as timing that corresponds to different pacemaker modes.  
Future work would be related to further investigations of the frequency range in which the Shannon energy is calculated (selected to be between 1000 and 2000 Hz in this study), and application of the designed algorithm over real ECG signals with pace artifacts.  
Conceptualization, I.J., I.I. and S.T.; methodology, I.J.; software, I.J.; validation, I.J., I.I. and S.T.; formal analysis, I.J., I.I. and S.T.; investigation, I.J., I.I. and S.T.; resources, I.J., I.I. and S.T.; data curation, I.J. and I.I.; writing--original draft preparation, I.J.; writing--review and editing, I.I. and S.T.; visualization, I.J.; supervision, I.I.; project administration, S.T.; funding acquisition, I.I. and S.T. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Bulgarian Scientific Research Fund, grant number JIH17/19.  
**Conflicts of Interest:** The authors declare no conflict of interest.  
\begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & \multicolumn{2}{c}{**This Study**} & \multicolumn{2}{c}{**Previous Study [22]**} & \multicolumn{2}{c}{**[PERSON] et al. [18]**} \\ \hline
**Test Dataset** & **Se (\%)** & **PPV (\%)** & **Se (\%)** & **PPV (\%)** & **Se (\%)** & **PPV (\%)** \\ \hline ECG+EMG & 100 & 98.0 & 99.4 & 89.3 & 99.5 & 97.5 \\ Clean ECGs & 99.9 & 98.3 & 99.3 & 99.0 & 98.9 & 100 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Accuracy of the designed threshold-based algorithm for pace pulses detection over the test dataset (390 clean ECGs, 312 ECG+EMG) for K = 10. Se and PPV achieved in our previous study over the same datasets [22], as well as Se and PPV reported by [PERSON] et al. [18].
# Real-Time, Content-Based Communication Load Reduction in the Internet of Multimedia Things
## 4 Results
### Video Quality Metrics
#### 4.3.2 Peak Signal-to-Noise Ratio (PSNR)  
PSNR is an objective video quality metric [73] based on second order statistics across all the pixels of the video frames compared. Therefore, it is an objective measure that does not directly reflect the human visual system. Nevertheless, it has been and remains in widespread use. A lower PSNR shows that noise, for example, errors in the video representation, has disrupted the signal strength, for example, the frame representation at the receiver. This study analyzes PSNR to find the accuracy of information. It is computed for the test videos using random sample of 260 frames from each video. Their average values are shown in Table 3 for the Y, U and V channels separately. Results show a desirable quality of image, indicating a limited distortion, considering the use of a lossy compression that is, JPEG, used in this study. Of course, when natural images are involved, that is, those from a Markov field of order one, the human viewer is usually unable to tell that a scene has been affected by (say) compression distortion, unless the original scene is available.  
Figure 11: Average Structural Similarity (SSIM) between original frames at the sender and reconstructed frames at the receiver for five video sequences.
## 3 Conclusions  
In this work, a frequency reconfigurable Hilbert fractal antenna has been designed and its electromagnetic performance has been numerically studied. The different switching states were responsible for achieving the desired operating characteristics. One of the features of our proposed antenna design is that it makes use of the Hilbert fractal antenna's length reduction to produce a medium to large discrete frequency shift. The designed proposed fractal antenna can generate a 0 to >17% continuous frequency shift within the operating frequency band. Moreover, the one segment fractal antenna shows a very high gain of 4.29 dBi. In addition, the two segment smaller electrical length fractal antenna achieved a significant amount gain of 2.42 dBi. The proposed antenna has numerous advantages, including its small size, low cost, ease of fabrication, and ease of integration. The designed antenna can be utilized in satellite communications, military applications, and modern communication devices (i.e., laptops and tablets), as well as in RTD devices.  
Figure 9: **The 3D and polar plot of the farfield gain of different electrical length two segment Hilbert fractal reconfigurable antenna in ordinary polarization in the PDLC. (a,b) Two segments with no cut (at 0.558 THz), (c,d) two segments with cut (large electrical length) left shift (at 0.555 THz), and (e,f) with cut (small electrical length) right shift (at 0.579 THz) of the fractal geometry.**  
**Author Contributions:** Conceptualization, W.-C.W. and P.G.; methodology, W.-C.W. and P.G.; software, P.G.; validation, W.-C.W. and P.G.; formal analysis, W.-C.W. and P.G.; investigation, W.-C.W. and P.G.; resources, W.-C.W.; data curation, W.-C.W., and P.G.; writing--original draft preparation, W.-C.W. and P.G.; writing--review and editing, W.-C.W. and P.G.; visualization, W.-C.W.; supervision, W.-C.W.; project administration, W.-C.W.; funding acquisition, W.-C.W. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This study was funded by the Ministry of Science and Technology, Taiwan (MOST 107-2221-E-007-054-MY3, 109-2221-E-007-110 and MOST 110-2221-E-007-069).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data presented in this study are available on request from the corresponding author. The data are not publicly available due to patent pending issues.  
**Conflicts of Interest:** The authors declare no conflict of interest.
# Dual-Polarization Conversion and Coding Metasurface for Wideband Radar Cross-Section Reduction
## 3 Angular Stability  
The metasurface response is rigorously evaluated through its angular stability performance. In practically every application, the metasurfaces' response must be independent of the electromagnetic wave's incidence angle. Our metasurface has been evaluated and optimized for various incidence angles. Figure 4 illustrates an evaluation of a metasurface's polarization conversion efficiency and AR under an oblique incident EM wave. The angular stability for linear polarization operation can be observed using the polarization conversion ratio, as illustrated in Figure 4a. Within two frequency ranges, the PCR shows a stable response up to an incidence angle of 40\({}^{\circ}\).  
On the other hand, as the oblique angle increases, a slight forward frequency shift is observed in both frequency bands. While the oblique incidence (35\({}^{\circ}\) and 40\({}^{\circ}\)) in the upper-frequency band only had an offset effect on the frequency bands, it had slight effects on the bandwidth of 12.37-13.03 GHz and had no impact on the circular polarization conversion at 11.80-12.29 GHz in terms of linear-to-circular polarization conversion, as shown in Figure 4b. Moreover, the AR response shows stability up to an incidence angle of  
Figure 4: Simulated results at oblique incidences: (**a**) PCR and (**b**) axial ratio (AR \(\leq\) 3 dB).  
Figure 3: (**a**) Calculated results of phase difference (deg) and amplitude ratio (\(r_{xy}/r_{yy}\)); (**b**) axial ratio (AR \(\leq\) 3 dB).  
30\({}^{\circ}\). Thus, under oblique incidence, the LP-CP conversion could maintain the multi-band function and remain stable in the higher frequency range.
# Application of Riemannian Seismic Ray Path Tracing in Salt Dome Prospecting
## 3 Development
### Seismic Ray Tracing Algorithmics  
In summary, the steps to determine the trajectories of seismic rays in this formalism are:  
1. Determine the velocity model \(v=v(q^{i})\) of the region under study, and with it, the refractive index \(n\) associated (see Equation (10)).
2. Construct the seismic space \(\big{(}\mathbb{M}^{d},\mathbf{g};n\big{)}\), by constructing its metric tensor \(\mathbf{g}\) induced by \(n\).
3. Obtain the Christoffel symbols associated with said metric tensor.
4. Determine the geodesic (differential) equations that would correspond to the seismic rays in said means (Equations (6) and (12)).
5. Establish the conditions of the seismic source (initial conditions for the geodesic equations).
6. Resolution of the geodesic equations.  
Regarding the last point, the geodesic equations (Equation (6)) yield the parametric geodesic trajectories (i.e., \(q^{i}=q^{i}(\lambda)\)), and these are usually a set of (if \(i=1,2,3\)) coupled second-order differential equations, which usually do not have analytic solution for cases where the velocity model is realistic. Thus, they are usually solved via numerical methods.
## 2 Materials and Methods
### Antioxidant Analysis  
Salicylic acid reacts with hydroxyl radicals (-OH) in the reaction system to produce 2,3-dihydroxybenzoic acid, which has maximum absorption peak at 510 nm. The -OH scavenging rate is calculated based on this absorbance [26]. The free radical scavenging rates of DPPH and ABTS were measured using a test kit. After being oxidized, ABTS was able to generate the blue-green cationic radical ABTS+, which exhibited a maximum absorption at 734 nm. The DPPH radical, which possessed a single electron, exhibited a purple color in its alcoholic solution and demonstrated strong absorption at 515 nm. In the presence of antioxidants, the DPPH radical was scavenged, resulting in a lighter colored solution. The change in absorbance at 515 nm was directly proportional to the degree of radical scavenging that had occurred. The antioxidant property was measured using the spectrophotometer (MAPADA, Shanghai, China).  
Determination of the Gallic Acid and Catechin Levels Using High Performance Liquid Chromatography (HPLC)  
The catechin level was determined using an HPLC system (Agilent 1260, Agilent Corporation, Santa Clara, CA, USA) equipped with an Agilent C18 (4.6 mm \(\times\) 150 mm \(\times\) 5 \(\upmu\)m) column. The sample volume was 10 \(\upmu\)L, the flow rate used was 1 mL/min, the detector used was a UV detector, the wavelength was set to 270 nm, the mobile phase A was a 1% acetic acid aqueous solution, and the mobile phase B was methanol. The initial composition of the mobile phase was 5% phase B. From 0 to 28 min, it linearly increased to 17% phase B. The mobile phase remained at 17% phase B until 38 min. Between 38 and 40 min, it linearly decreased back to 5% phase B. Finally, the composition maintained at 5% phase B until the end of the experiment at 45 min. The gallic acid and catechin contents were calculated according to the peak area [27; 28].