esa-sceva/satcom-chunk-collection huggingface dataset:
## 2 RPL in the Literature
### RPL Improvements and New Metrics  
Several papers have proposed new improvements in RPL protocol to enhance the performance. In [22], [PERSON] et al. proposed new modifications to RPL based on Contiki: By changing the Contiki's behavior specially routing and neighbor table, they outperformed the original implemented Contiki's RPL performance in terms of Packet Delivery by 200%.  
In [23], authors proposed a permanent probing mechanism by changing the Trickle L2 algorithm to enable a faster DODAG construction by delaying the bootstrap process till a predefined link quality is reached. They showed that the Trickle L2 mechanism can achieve better network convergence while reducing the total communication overhead.  
In [24], they proposed a new mechanism to find and calculate link quality instead of considering a new neighbor with a bad link quality. They find that testing many neighbors can find the best one with the best link quality instead of sticking to only acceptable ones.  
In [25], a new evaluation study of RPL performance based on simulation for large-scale outdoor scenarios was performed. RPL works well concerning the level of control overhead and network delay and introduces a repair mechanism of the corrupted radio links and tuning of the trickle timer parameters to manage the control traffic overhead with respect to data traffic. Additionally, it can also make use of the local repair mechanisms for better and quicker repairing disruption of local connection than global repair mechanisms.  
In [26] RPL applicability in SG monitoring systems is investigated. Results showed that RPL makes rapid changes and adaptations to any new routing knowledge thus proving to be a good and smart choice for the SG applications. We are badly in need to study RPL behavior in realistic scenarios and different environments. Different RPL metrics were proposed in previous studies to evaluate the RPL performance and it was observed that a lot of enhancement and optimizations can be done with the RPL network.  
In this paper, we introduce a new RPL performance evaluation using two different scenarios of IOT-LAB testbed with 140 nodes as an experimental scenario and a simulated scenario of Cooja simulator with randomly distributed 1000 nodes. Two routing metrics will be investigated, the Objective Function 0 (OF0) that used the hop count to calculate the routes to destination and the Expected Transmission Count (ETX) that used the expected number of packet transmission to the destination. Both metrics were evaluated in terms of four performance metrics: Control Traffic Overhead, Packet Delivery Ratio, Network Latency, and Power consumption, to propose the most efficient Objective Function that appropriate the SG applications, especially AMI. Results show that ETX outperforms OF0 in large-scale scenarios and provides better routes selection and can be considered as the default objective function of RPL protocol in AMI applications based WSN.
## Nomenclature
  
\(\varphi\) & ball azimuth angle, rad \(\kappa\) & \(a/b\) \(\
u\) & Poisson's ratio \(K_{\rm e}\) & deflection coefficient at ball and outer raceway contact, N/mm\({}^{1.5}\) \(K_{\rm i}\) & deflection coefficient at ball and inner raceway contact, N/mm\({}^{1.5}\) \(r_{\rm i}\) & groove curvature radius of inner raceway, mm \(K\) & global stiffness matrix of the shaft \(K^{\rm e}\) & stiffness matrix of the beam element \(\delta\) & displacement vector of the shaft nodes, mm \(E\) & modulus of elasticity, GPa \(I\) & moment of inertia of the shaft section, mm\({}^{4}\) \(L\) & length of beam element, mm \(L_{\rm s}\) & total length of the shaft, mm \(k_{\rm b}\) & number of angular contact ball bearings supporting the shaft \(\varepsilon_{\rm b}\) & calculation error of ball spinning speed \(\varepsilon_{\rm c}\) & calculation error of ball orbit speed \(\varepsilon_{\rm\beta}\) & calculation error of ball pitch angle \(\delta_{\rm a}\) & axial displacement caused by constant-displacement preload or constant-force preload, mm \(\theta_{\rm s0}\) & angular misalignment of outer ring of ball bearing around \(x\)-axis of bearing local coordinate system, mrad \(\theta_{\rm y0}\) & angular misalignment of outer ring of ball bearing around \(y\)-axis of bearing local coordinate system, mrad \(L_{\rm 10r}\) & basic reference rating life of bearing, in million revolutions \(L_{\rm i}\) & basic reference rating life of inner ring, in million revolutions \(L_{\rm e}\) & basic reference rating life of outer ring, in million revolutions \(Q_{\rm ci}\) & basic dynamic load rating of inner ring, N \(Q_{\rm ce}\) & basic dynamic load rating of outer ring, N \(Q_{\rm ei}\) & equivalent dynamic load for rotating inner ring, N \(Q_{\rm ee}\) & equivalent dynamic load for fixed outer ring, N
# A Comprehensive Review of In-Body Biomedical Antennas: Design, Challenges and Applications
###### Abstract
Furthermore, the fabrication and testing of such miniaturized in-body antennas inside the human body are extremely challenging due to the inadequately accredited animal laboratories, along with major health and safety related issues [22; 23]. The growing research in this area demands a comprehensive overview in order to acquaint the new researchers and antenna designers with the state of the art and current developments. This review work aims to describe the design specifications, implementation and testing techniques, challenges and different applications of in-body antennas. Following the Introduction, the paper is divided into six sections. Section 2 briefly highlights the design specifications of in-body antennas. Section 3 explains the in-body antenna design, manufacturing and testing process. Section 4 outlines the different challenges in the development of in-body antennas. Section 5 details the different antenna types being  
Figure 1: Types of BWCS. used in different IBBD applications and compares their performances critically. Section 6 briefly discusses the limitations of the current in-body antenna designs and indicates future research scopes. Finally, the conclusions are drawn in Section 7.
## 3 Results and Discussion
### Compressive and Flexural Strengths  
Figure 9 shows the compressive and flexural strengths of different mix designs based on ASTM C 39 [38] and ASTM C 78-2002 [39], for which two standard 15 \(\times\) 30 cm cylindrical and 10 \(\times\) 10 \(\times\) 50 cm prismatic specimens were cast, cured for 28-days, and averaged for the final result; Si100C shows the highest compressive and flexural strength while Ca100N shows the lowest. A comparison of mix designs containing silica sand reveals that specimens made of manufactured sand have higher compressive and flexural strengths than those made of natural sands; for the calcareous sand, the trend is the same. Hence, it can be concluded that mixing siliceous and calcareous sands will increase the compressive and flexural strengths, and the increase is much greater than that produced by each type of sand alone. The point worth noting in comparing the compressive strength variations of specimens containing mixed sands with those containing homogeneous sands is that when  
Figure 8: The bulk density of different mixes.  
Figure 7: Investigation of different RCCP micro/macro-textures by British pendulum test setup.  
several sand types are combined, the strength reduction is less, concluding that mixed-sand specimens are less dependent on the sands' crushing rate.
# Research and Design of the RF Cavity for an 11 MeV Superconducting Cyclotron
## 6 Conclusions  
The miniaturization of the resonator is achieved by introducing SIR into the RF cavity of a cyclotron, and the equivalent circuit method is used to simplify and equate the complex RF cavity so as to realize further analysis. The computational results show that the error of the equivalent circuit method and the numerical simulation calculation method can be up to 0.1% at the target frequency. In addition, multiple linear regression analysis can be used to predict the resonance frequency under multiple parameters, and the error of the results is basically kept within 1%. Therefore, a combination of the two methods can greatly simplify the design process and ease the design of the RF cavity of the cyclotron, save computational time, and be suitable for engineering applications.  
Conceptualization, W.-S.W. and Z.-F.H.; methodology, Y.W.; software, Y.W.; validation, Z.-F.H. and W.-S.W.; formal analysis, Z.-F.H., Y.W. and H.-F.Y.; investigation, P.-P.Z., Y.W. and Z.-F.H.; resources, Z.-F.H.; data curation, Y.W., H.-F.Y. and P.-P.Z.; writing--original draft preparation, Y.W.; writing--review and editing, Z.-F.H.; visualization, Y.W. and H.-F.Y.; supervision, W.-S.W. and Z.-F.H.; project administration, Z.-F.H.; funding acquisition, W.-S.W. and Z.-F.H. All authors have read and agreed to the published version of the manuscript.  
This research was supported by the Major Development Project of the Shanghai Institute of Applied Physics, Chinese Academy of Sciences under Grant Y951011031.  
Not applicable.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Method** & **RMSE** & **R2** & **Regression Equation** \\ \hline Numerical simulation & 0.040 & 0.998 & f = 57.573 + 0.3172 \(\times\)\(r_{\rm ic}-0.0174\)\(\times\)\(r_{\rm oc}-0.1005\)\(\times\)\(L\) \\ \hline Equivalent circuit & 0.052 & 0.998 & f = 56.856 + 0.3995 \(\times\)\(r_{\rm ic}-0.0183\)\(\times\)\(r_{\rm oc}-0.1054\)\(\times\)\(L\) \\ \hline \hline \end{tabular}
\end{table}
Table 2: Performance of the RF cavity resonant frequency prediction based on multiple linear regression models.  
Figure 13: Performance of the RF cavity resonant frequency prediction based on multiple linear regression models.  
Data Availability Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.  
The authors would like to thank colleagues [PERSON] of the Shanghai Institute of Applied Physics for their help with the article.  
The authors declare no conflicts of interest.
## 1 Introduction
### Interactive Technologies as a Valuable Tool to Implement Non-Pharmacological Approaches  
Over the past few decades, the role of technological approaches in health settings has been a matter of scientific research. [PERSON] and colleagues [18] described two possibilities of technology use in populations with cognitive impairment: (1) assistive technologies for cognition, such as \"low tech\" devices (e.g., written lists/checklists), \"mid tech\" devices (e.g., programmable wristwatches), and \"high tech\" devices (e.g., smartphones); and (2) rehabilitation technologies for cognition, such as \"low tech\" devices (e.g., paper-and-pencil worksheets), \"mid tech\" devices (e.g., Snoezelen), and \"high tech\" devices (e.g., serious games) [18].  
Concerning interactive technologies for cognitive stimulation, [PERSON] and colleagues [19] studied the interaction of IwD with different technologies, aiming to develop a serious game adapted to this clinical population. They concluded that although most IwD were able to perform the proposed tasks in the different technological devices (e.g., head-mounted display, leap motion), their performance and experience varied according to their profile (e.g., cognitive status, schooling, age), which suggested the need for customizing technology to IwD [19].  
Accordingly, [PERSON] and colleagues (2019) developed a platform--Musiquence--that is compatible with different technologies (such as computers, tablets, smartphones, and augmented reality) (cf. Figure 1,) and can be adapted to each patient's needs (e.g., motor difficulties, vision problems, tremble) and cognitive profile. In addition, Musiquence incorporates two key elements of CST--music, and reminiscence--in cognitive stimulation activities for IwD, since the content can be personalized to the user [17]. Caregivers can add text, images, and music when creating cognitive stimulation tasks, according to the IwD's personal preferences. Musiquence enables the gamification and personalization of the following six types of activities:  
* Reality Orientation--a quiz-like activity that includes date and time information.
* Creative Drawings--a puzzle-like game in which missing parts must be drawn using real paper and crayons.
* Activities of Daily Living (ADL)--a puzzle-like game in which real physical objects (e.g., toothpaste) must be used to answer.
* Search Objects--an exploration game where hidden images (e.g., cats) must be found using a magnifying glass.
* Knowledge Quiz--a quiz-like activity in which the correct answer must be selected.  
* Association--a categorizing activity where items must be organized according to the instructions (e.g., separate cars from motorcycles).  
Musquence includes an \"editor\" tool, in which the health professional can create, replicate, add, and eliminate different activities according to the defined goals. Then, activities are performed by IwD according to a pre-selected order. This allows systematic inclusion and presentation of multimodal stimuli that would not be easily implemented in paper-and-pencil cognitive stimulation activities [17].
# The Euler-Type Universal Numerical Integrator (E-TUNI) with Backward Integration
## 6 Analysis of the Numerical Accuracy of E-TUNI Using Landau Symbols
### Numerical Accuracy of the Conventional Euler Method  
The explicit Euler method is a numerical integration technique for solving ordinary differential equations of the form:  
\[\frac{dy}{dt}=f(t,y),\quad y(t_{0})=y_{0}. \tag{22}\]  
The formula for the method is:  
\[y_{n+1}=y_{n}+hf(t_{n},y_{n}), \tag{23}\]  
where \(h\) is the integration step; \(y_{n}\) is the approximation of the exact solution \(y(t_{n})\); \(f(t_{n},y_{n})\) is the instantaneous derivative of the solution at the point \((t_{n},y_{n})\). Therefore, it is a well-known result that the difference between the exact solution and the Euler approximation is given by:  
\[y(t_{n+1})-y_{n+1}=\frac{h^{2}}{2}y^{\prime\prime}(t_{n})+O(h^{3}). \tag{24}\]  
Therefore, the accuracy of the method is evaluated by two errors: (i) The local truncation error \(E_{\text{local}}=O(h^{2})\) and (ii) the global truncation error \(E_{\text{global}}=O(h)\). Understanding the global error is quite simple; since the Euler method performs \(N=\frac{T}{h}\) steps to integrate up to a time \(T\), the global error is obtained by adding the local errors over this interval. Finally, the accuracy of the Euler method is first order since the global error is \(O(h)\). This result shows that the Euler method is accurate only for small steps, and higher-order methods such as Runge-Kutta are preferable to obtain greater accuracy.
## Numerical Simulation and Parametric Analysis
### Discussions
#### 4.4.4 Effect of Thickness of Steel Plate  
Figure 17 shows the influence of the thickness of the steel face plates on compressive resistance and ductility of SDC walls with two types of thicknesses of rubber layers (2 mm and 5 mm). It is found that the thickness of the steel face plate significantly influences the ultimate compressive resistance of the SDC wall. Increasing the thickness of the steel plate from 3 mm to 4 mm and 5 mm, the ultimate compressive resistance of the SDC walls with 2 (5) mm rubber layers was increased by 14.2% (10.5%) and 27.8% (24%), respectively. This is because increasing the thickness of the steel face plates would contribute to (i) rising confinement on the concrete core, and (ii) increasing the buckling resistance and larger out-of-plane buckling stiffness of the steel plate [7].  
Increasing the thickness of the steel face plate also resulted in a significant enhancement of the ductility of the SDC walls. As the thickness of the steel face plates increases from 3 mm to 4 mm and 5 mm, the DI ratios of the SDC walls with the 2 mm (5 mm) rubber layer increase by 23.2% (55.3%) and 116.7% (130.8%). The increases are caused by the increased steel content of the cross-section. One interesting observation is that the influence of the plate thickness on the ductility of the SDC wall is more significant for the specimens with 5 mm rubber layers than the specimens with 2 mm rubber layers. This can be explained by that the concrete core with thicker steel plates can be more insensitive to the weakening effect of the rubber layer. Although the concrete core and steel plates are separated by the damping interlayer, the thicker steel plates still can provide relative effective lateral confinement on the concrete core.
## 3 Results and Discussion
### AC Conductivity of the PLC Nanocomposite  
The frequency-dependent conductivity of the PLC nanocomposite with the influence of EB irradiation's dose and temperature is shown in Figure 12. At low frequencies, as well as temperatures, the conductivity exhibited similar patterns; there was no maximum change at all doses. The total conductivity in the polymer matrix is the sum of the microscopic conductivity depending on the dopants and the macroscopic conductivity depending on the molecular orientations in the polymeric materials [44]. The increase in conductivity depends on the number of conduction paths established within the polymer nanocomposite. The width of the potential barriers decreased in the bulk regions as a result of the electrical path (i.e., network) developed in the polymer matrix. Consequently, the charge carriers are able to move freely via a hopping mechanism from one site to another, thereby increasing conductivity. The conductivity further increases with an increase in the EB irradiation dose, because the EB energy is able to change the polymer chemical bonding by the chain scission process in such a way that the polymer structure converts as hydrogen depleted carbon network and hence this network makes the polymer more conductive [45]. The ac conductivity (\(\sigma_{\text{ac}}\)) was calculated by the equation,  
\[\sigma_{\text{ac}}=\omega c_{\text{p}}d\tan\!\delta/A \tag{8}\]  
where \(d\) is the thickness of the sample, \(A\) is the electrode area, \(\omega\) is the angular frequency, and \(\tan\delta\) is a loss tangent [46]. An increase in the ac conductivity with an increase in the EB dose was observed, which was mainly due to the release of trapped charges activated at higher frequencies. This is attributed to the formation of single- and/or double-helical bonds due to the large electronic energy loss along their trajectories by an inter-chain  
Figure 11: Variation in the dielectric constant (\(\varepsilon^{\prime}\)) with (**a**) temperature and (**b**) EB irradiation doses.  
polymer cross-linking process, thus the number of free charge carriers increased in the polymer matrix after irradiation [4].
### Contributions and Scope  
The main contributions of this research can be summarized as follows:  
* The reformulation of the classical backward-forward power-flow method for application to distribution networks with the ability to handle radial and meshed configurations by rewriting the branch variables into nodal variables using the branch-to-node incidence matrix.
* The parametric independence of the power-flow formulation, as no assumptions about relations reactance/resistance, are required in the proposed matricial formulation.
* The possibility of guaranteeing convergence under well-defined voltage conditions by applying the Banach fixed-point theorem to the recursive solution, which only requires that the short-circuit current be more significant to the load current in all the nodes to ensure the convergence of the algorithm.  
* The presentation of the proposed matricial formulation in an intuitive manner to introduce students of electrical engineering to power-flow analysis by providing the MATLAB/OCTAVE algorithm for solving a small test feeder as a numerical example comprising radial and meshed structures.  
It is important to mention that a similar approach was previously proposed in [13] that combined branch-to-nodal matrices with triangular matrices; moreover, its convergences were also proved. However, the authors of [13] did not present the behavior of the \(\theta-\)coefficient as a function of the load current and the short-circuit current relations per node. In addition, a simulation case is presented herein, where the power system contains a voltage-controlled node (VC node) in a small transmission network, which demonstrates that the proposed matricial approach is extensible to power system applications with multiple meshes and VC nodes.
# MIMO Channel Estimation in an SDR Platform for Evaluation of D&F Relay Nodes
###### Abstract  
Relay Nodes (RNs) have received special attention as a radio access technology which can overcome channel fading and improve the channel capacity in high-speed and dense vehicle environments. RNs have been the object of standardization by the 3 GPP; however, this process has not been accompanied by the development of hardware that allows for evaluation of the advantages of RNs. Software Defined Radio (SDR) has emerged as a promising technology to implement the concept of RNs at low cost. In this paper, a detailed study of the MIMO wireless channel between an evolved Node-B (eNB) and an RN is carried out. The developed algorithms are implemented in an SDR platform for Decode-and-Forward (D&F) relay node evaluation, resulting in significant improvements of its capabilities on the MIMO channel. A pilot symbol-assisted channel estimation algorithm based on combinations of the Least-Squares (LS) technique and Bi-Cubic (BCI), Bi-Linear (BLI), and Bi-Nearest Neighbors (BNNI) interpolation methods is considered. Furthermore, the Minimum Mean Square Error (MMSE) and Zero-Forcing (ZF) equalization schemes are studied. In the tests conducted, Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) scenarios are considered, demonstrating the capabilities of the developed platform. The performance measurements using different modulation schemes are compared under the same conditions. The simulation results show that the LS technique together with the BCI and MMSE methods performed the best among all evaluated channel estimation and equalization algorithms, in terms of the Error Vector Magnitude (EVM) performance of the received Resource Grid (RG). Furthermore, we show that the Bit Error Rate (BER) and throughput of the core network increase when using the 2 \(\times\) 2 MIMO technique.  
MIMO; channel estimation; interpolation; equalization; BER; throughput; SDR platform; relay node; decode-and-forward +
Footnote †: journal: Electronics Electronics