esa-sceva/satcom-chunk-collection huggingface dataset:
# Volumetric Techniques for Product Routing and Loading Optimisation in Industry 4.0: A Review
## 4 Volumetrics
### Algorithmic Approaches
#### 4.5.1 Application of Greedy Algorithms  
Aiming to gain insights into the versatility and limitations of Greedy Algorithms, we delve into six distinct studies to examine how Greedy Algorithms are employed in resolving complex combinatorial problems.  
The study presented by [PERSON] et al. [PERSON] et al. (2018) primarily focuses on the application of Greedy Algorithms to tackle specific instances of the bin-packing problem, particularly for the Schwerin and Falkenauer U benchmark classes. Their study showcases the efficacy of Greedy Algorithms in providing efficient solutions for a substantial percentage of instances within these classes. Notably, the Greedy Algorithm achieves optimal solutions for all instances in the Schwerin class and approximately 91% of the instances in the Falkenauer U class. Additionally, their introduction of pre-processing procedures simplifies subsequent packing processes.  
Another study, primarily focused on solving the Container Loading Problem (CLP), proposes a heuristic algorithm that leverages a multiphase Greedy Strategy. It begins by assuming that items in a layer must share the same shape, employing a systematic approach of creating good layers out of high-quality stacks, and packing these stacks into containers. It exhibits versatility, with the potential for application in the Pallet Loading Problem and the 3D Bin Packing Problem (3D-BPP) [PERSON] et al. (2019).  
The Greedy Algorithm is also presented as a core component of solutions proposed by two studies [PERSON] et al. (2018); [PERSON] et al. (2018) to address a spectrum of packing problems, including the CLP, the Pallet Loading Problem, and the 3D-BPP. The main difference between the two solutions is that the authors of the 2014 study [PERSON] et al. (2018) propose a Heuristic Binary Tree Search Method (HBTS), which iteratively selects items to be loaded into the container, considering specific criteria, such as item dimensions and other constraints. A similar solution, although primarily focused on the solution of the CLP, presented in another 2014 study [PERSON] et al. (2018) proposes the use of a Greedy Algorithm, specifically the Deepest Bottom Left with Fill (DBLF), as part of its hybrid approach. The authors employ the DBLF to generate initial solutions for the CLP.  
The Greedy Randomised Adaptive Search Procedure (GRASP) is proposed by a recent study [PERSON] et al. (2018) to address the 3D-BPP and the Vehicle Routing Problem (VRP). The authors' GRASP algorithm plays a crucial role in creating initial solutions for these problems. By employing a constructive phase that forms clusters of customers based on their distances to the warehouse, the algorithm introduces randomness to the clustering process, enhancing the exploration of solution spaces. The paper does not explicitly discuss alignment with the Industry 4.0 framework, but the efficient packing and routing it entails hold relevance to Industry 4.0's goals.
## 4 Discussion
\begin{table}
\begin{tabular}{c p{284.5 pt}} \hline \hline
**Reference** & \multicolumn{1}{c}{**Description**} \\ \hline
[16] & Theoretical model and ray-tracing simulation for a near-ground channel at mmw band. \\  & Analysis of diffuse scattering in MIMO applied to near-ground channel. \\ \hline
[25] & Results of RSSI measurements with distance for a WSN in indoors, outdoors, different blocking conditions and antenna elevations. Only flat floors. Unknown frequency band used. _Not a model_. \\ \hline
[17] & Two-slope log-distance model for the path loss for a WSN at 868 MHz in an open area. \\ \hline
[24; 25; 26; 27; 28; 29; 30; 31; 32] & Software simulation of limited scalability only valid for certain environments. \\ \hline
[18] & Analysis of impact of foliage on near-ground radiowave propagation for battlefield sensor networks operating at 300 MHz and 1900 MHz. _Not a model_. \\ \hline
[28] & Measurement results for ground-based UHF band communicators in urban terrain for both line-of-sight (LOS) and non-line-of-sight (NLOS) links. _Not a model_. \\ \hline
[23; 29] & Numerical solver-based simulation for near-ground long range propagation; computational complexity limits a large number of nodes in the simulated network. _Not a model_. \\ \hline
[30] & Simple mathematical path loss model; overlooks the significant impact of terrain roughness and electrical properties on the channel transfer characteristics. \\ \hline
[23] & Theoretical two-slope path model based on the condition of 50% of obstruction for the first Fresnel zone. \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Description of models and experimental results reported for near-ground radio channels.
## 3 Results and Analysis of Influencing Factors
### The Impact of Drill String Properties on Signal Attenuation
#### 3.5.3 The Impact of Drill String Dimensions on Signal Attenuation  
Under different drilling conditions, the dimensions of drill pipes vary. Common diameters of drill pipes are 60 mm, 73 mm, and 89 mm, among others. With the drill pipe wall thickness and casing size kept constant, it has been observed that as the diameter of the drill pipe increases, the attenuation of the electromagnetic wave signal correspondingly intensifies. According to Figure 9. Taking the transmission of 100 m as an example, the signal attenuation is 118.2 dB for a drill pipe with an outer diameter of 60 mm, 128.96 dB for 73 mm, and reaches 141 dB for 89 mm. However, within a transmission range of 20 m, the received signal gradually strengthens with the increase in drill pipe diameter. But beyond 20 m, an increase in drill pipe diameter actually leads to a weakening of the received signal. Therefore, in short-distance transmission, choosing a drill pipe with a larger diameter may have advantages, while for long-distance transmission, thinner drill pipes may be more conducive to the propagation of electromagnetic waves.
## 2 Experimental Setup
### Test Arrangement  
To generate the equivalent horizontal oscillatory flow derived from wave action, the semi-submerged cylinder is forced to oscillate in harmonic motions in the IL direction ([PERSON] 1987) [21]. The instantaneous displacement \(X(t)\) and corresponding velocity of the forced motion \(U(t)\) can be respectively indicated as what follows:  
\[X(t)=A_{m}\sin\biggl{(}\frac{2\pi}{T}t\biggr{)} \tag{2}\]  
\[U(t)=A_{m}\frac{2\pi}{T}\cos\biggl{(}\frac{2\pi}{T}t\biggr{)} \tag{3}\]  
where \(A_{m}\) and \(T\) are respectively oscillation amplitude and period.  
To describe the hydrodynamic features of the semi-submerged cylinder, the key parameters including KC number, Reynolds number (Re) and Stokes number (\(\beta\)) [3; 7; 18; 22] should be considered, which can be respectively expressed as,  
\[KC=\frac{2\pi A_{m}}{D} \tag{4}\]  
\[\text{Re}=\frac{2\pi A_{m}D}{T\cdot v} \tag{5}\]  
\[\beta=\frac{\text{Re}}{KC}=\frac{D^{2}}{vT} \tag{6}\]  
where \(v=1.0\times 10^{-6}\) m\({}^{2}\) s\({}^{-1}\) is the kinematic viscosity coefficient of water.  
However, the free surface effects are the distinctive characteristics for flow past a semi-submerged cylinder. The Froude number (\(Fr\)) is also an important parameter for this hydrodynamic load on the cylinder [19] and can be defined as,  
\[Fr=\frac{U_{m}}{\sqrt{gh}} \tag{7}\]  
where \(U_{m}=A_{m}\cdot(2\pi/T)\), \(h=0.5\)D, \(h\) is the submerged depth.  
From the definition of the four parameters in Equations (4)-(7), conflicts are clear between the Froude number and Stokes number. In order to investigate the hydrodynamic force on semi- submerged cylinder in an oscillatory flow, the test cases were divided into four groups according to their KC numbers, as summarized in Table 1. Each test group maintained the same KC number with different Stokes number ranging from 5435 to 11,364. We should note that the test cases are designed to reveal preliminary hydrodynamic force features and the cases at larger KC number will be a promising direction for the future work.
# Energy-Efficient Partial LDPC Decoding for NAND Flash-Based Storage Systems
## 6 Hardware Architecture
### Decoding Architecture  
A block diagram of the proposed decoding architecture is shown in Figure 7. Except for the dedicated syndrome checking (SYN) unit, the decoding architecture is identical to the conventional layered min-sum decoder [18]. Each decoding function unit (DFU) performs the independent check node operation in parallel, and the corresponding LLR values and the intermediate C2V values are stored in LMEM and C2V memories, respectively. The detailed architecture of the DFU is shown in Figure 8. Through the shuffle network, the appropriate LLR and C2V values are obtained, followed by number system conversion, addition and subtraction operations. For a fair evaluation of the implementation, the most efficient method among the existing approaches has been applied for the Minimum search logic [19; 20].  
The shuffle and de-shuffle networks align the LLR and C2V values. In the conventional architecture, all syndromes are checked in each DFU operation since the conventional decoding algorithm always uses the full H-matrix. However, the proposed partial LDPC decoding uses the partial H-matrices instead of the full H-matrix when the channel is reliable. Since decoding with the partial H-matrices does not compute all check node equations and syndromes, the dedicated SYN unit, which checks remaining syndromes, is additionally applied. As a result, proposed partial LDPC decoding can be applied by adding a simple SYN unit to any existing structure with ease.  
\begin{table}
\begin{tabular}{l c c c} \hline \hline  & **Code 1**[12] & **Code 2**[18] & **Code 3** \\ \hline Target system & SSD & SSD & IEEE 802.11 ac \\ Code type & Array & EG-LDPC & PEG \\ Cyclic & QC & Cyclic or QC & QC \\ User-message size & 4 KB & 8 KB & 1944 bits \\ Code rate & 0.9 & 0.96 & 0.5 \\ Target frequency (MHz) & 250 & 250 & 500 \\ Area (Equation gate count) & 22.1 k & 38.4 k & 6.6 k \\ \hline \hline \end{tabular}
\end{table}
Table 1: Areas of the Syndrome Checking Logic for Various Sizes of LDPC Codes in 65 nm CMOS.  
Figure 7: The prototype decoder for the proposed energy-efficient partial LDPC decoding algorithm for the (607, 60, 6) array LDPC code.
## 3 Proposed Scheme: FRBP
### Real-Time Broadcast Tree Construction
```
1:\(Dist(i,j)\): distance between node \(i\) and \(j\)
2:\(SingleHopDelay(i,j)\): single hop delay during data transmission from \(i\) to \(j\)
3:\(DDS\): desired delivery speed
4:\(N_{S}\): neighbors' set of node \(i\)
5:\(PCS_{i}\leftarrow\{n\in NS_{i}|Dist(src,i)-Dist(src,n)>0\}\)\(\triangleright\) parent candidate set closer to a source than node \(i\)
6:\(PCSRB_{i}\leftarrow\{j\in PCS_{i}|\frac{Dist(i,j)}{SingleHopDelay(i,j)}\geq DDS\}\)\(\triangleright\) parent candidate set for real-time broadcasting
7:if\(PCSRB_{i}==\)then\(\triangleright\) if node \(i\) has no candidate satisfying a desired speed
8:\(parentNode_{i}\leftarrow\underset{j\in PCS_{i}}{\operatorname*{arg\,max}}\{ \frac{Dist(i,j)}{SingleHopDelay(i,j)}\}\)\(\triangleright\) designate a parent node having the maximum delivery speed
9:endif
10:\(T\leftarrow\{t\in PCSRB_{i}|min(HopCount(t))\}\)
11:\(parentNode_{i}\leftarrow\underset{t\in T}{\operatorname*{arg\,max}}\{Dist(src,t)\}\)
```  
**Algorithm 1** Real-time broadcasting tree construction  
Note i's neighbor table  
Figure 2: An example of parent election through Desired Delivery Speed (DDS).
# Differential Characteristics Based Iterative Multiuser Detection for Wireless Sensor Networks
## 4 Simulation Results and Discussions
### BER Performances of Different \(E_{b}\)/\(N_{0}\)  
In this subsection, we consider the 20 and 50 user conditions. The number of iterations for the proposed multiuser detection algorithm is 5. The performance of MF, DEC, MMSE and OMUD are compared.  
Assuming all users have the same power at the receiver, simulation results are illustrated in Figure 6. From the figure it is clear that the BER performance of the proposed iterative multiuser detection method is superior compared with MF, DEC, and MMSE. In 20 user conditions, it even coincides with OMUD. In 50 user conditions, there still exists a considerable gap between the proposed multiuser detection algorithm and OMUD. Besides, it can be seen that for the AWGN channel and the multipath IEEE 802.15.4a channel we can get similar results.  
Figure 5: The BER performance with different number of iterations (50 users). (**a**) AWGN; (**b**) IEEE 802.15.4a CM1.  
Figure 6: The BER performance with different \(E_{b}/N_{0}\). (**a**) AWGN, 20 users; (**b**) AWGN, 50 users; (**c**) IEEE 802.15.4a CM1, 50 users.
## 3 Satellite Selection Algorithm  
Currently, the major global satellite navigation systems include the United States' GPS, China's BDS, Russia's GLONASS, and Europe's Galileo, making up the four major systems. With the development of multi-constellation and multi-frequency satellite navigation systems, integrated navigation systems can obtain more pseudo-range and pseudo-range rate observations during the measurement update period. If all observation signals are directly input into the filter without any screening, the correlation matrix will be large, leading to significant computational and memory consumption issues. Furthermore, incorrect observation inputs would cause deviations in the filtering results. Therefore, in order to achieve real-time and precise tightly integrated navigation results, it is necessary to both consider the number of satellite observation inputs and ensure the accuracy of the observations. This chapter provides a detailed introduction to the evaluation indicators of satellite positioning accuracy, as well as the satellite selection algorithm used in the integrated navigation system designed in this paper.
## 1 Introduction
In this work, we present an innovative comparative analysis of the performance of four cation exchange materials: two commercially available resins based on poly-styrene-divinylbenzene (PS--DVB) and polyacrylic-divinylbenzene (PA--DVB), and two materials not conventionally used for this application, consisting of a sulfonated tetra-fluoroethylene-based material (TFSA) derived from recovered Nafion and Organosolv lignin (OGL), recognized as a sustainable and naturally sourced material. The analysis focuses on metal removal efficiency, selectivity, and adsorption kinetic parameters, providing a detailed overview of the potential and limitations of these materials for the purification of water contaminated with heavy metals of interest, such as Cu\({}^{2+}\), Pb\({}^{2+}\), Co\({}^{2+}\), and Ni\({}^{2+}\) (additional results on Ag\({}^{+}\) are reported in the Supplementary Materials). The ion exchange capacities of the different metal-resin pairs were evaluated through batch experiments, quantifying the metal sequestration via ICP-OES analysis and correlating the results with an analysis of the kinetic parameters. This experimental study serves as a fundamental starting point for understanding the actual potential of the tested materials. The findings suggest ample opportunities for optimization, paving the way for their application in both industrial and environmental contexts, with a particular focus on the recovery of critical resources in alignment with circular economy principles.
## 7 Numerical Analysis  
To validate the proposed model, the IEEE 14-bus system is applied [29]. A wind farm with 100 2-MW DFIGs is connected to bus 7 through the VSC-HVDC. The rated frequency is 50 Hz. The parameters related to the frequency regulation of the SG and DFIG may be found in [26]. Other parameters are given by, \(k_{\rm der}\) = 20%, \(\upsilon_{\rm Im}\) = 8.79 m/s, \(\upsilon_{\rm Im}\) = 11.09 m/s, \(C_{\rm DC}\) = 3.75 mF, \(N\) = 2, \(S_{\rm VSC}\) = 100 MW, \(U_{\rm DC}\)= 100 kV. The adopted scenario of the load disturbance is the increase of active load at bus 13 (30 MW) and bus 14 (20 MW).
# Mixed-Integer-Based Path and Morphing Planning for a Tensegrity Drone
## 3 Problem Statement
### Path Planning as a Mixed-Integer Convex Program  
Assume a drone is required to find a path from point \(\mathbf{r}_{s}\) to point \(\mathbf{r}_{f}\) in \(K\) steps while remaining inside obstacle-free space. This implies that for any step \(k=1,\...\ K\), the robot needs to be inside at least one of the polytopes \(\mathcal{A}_{t}\). Problems of this class can be solved using the mixed-integer formulation, and the big-M method in particular [47].  
Given binary variables \(s_{k,t}\in\{0,\ 1\}\), the region-fit constraint in the optimization problem described above can be written as follows:  
\[\begin{cases}\mathbf{A}_{t}(\mathbf{r}_{i}+\mathbf{x}_{k})\leq\mathbf{b}_{t} +\mathbf{1}\cdot M(1-s_{k,t}),\ \forall i,t\\ \sum\limits_{t=1}^{T}s_{k,t}=1\end{cases} \tag{6}\]  
where \(\mathbf{x}_{k}\) is the position of the center of mass of the structure on the \(k\)-th step, \(T\) is the number of polytopes \(\mathcal{A}_{t}\), and \(M\) is a large scalar constant, chosen such that \(\mathbf{A}_{t}(\mathbf{r}_{i}+\mathbf{x}_{k})\leq\mathbf{b}_{t}+\mathbf{1} \cdot M\) holds for all \(\mathbf{x}_{k}\) in the admissible range.  
Note that the use of big-M relaxation increases the number of constraints for each step from \(n\) to \(n\cdot T+1\), where \(n\) is the number of nodes in the structure.
# Data Hiding and Authentication Scheme for Medical Images Using Double POB
## 3 The Proposed Scheme  
This part proposes a new scheme based on double POB system for medical image hiding and authentication. In the use of medical images, users are more concerned with the information in the brighter areas, which is called the ROS (region of significance), and the information in the darker areas is redundant in most cases. Therefore, in order to minimize the degradation of medical image quality, the image owner performs image preprocessing on the ROS for operation in the first place and then inserts secret data and authentication bits to generate two shares, which are then transmitted to the receiver. After the receiver authenticates the image, they extract the ciphertext information and complete the lossless recovery. The work of the image owner is shown in Figure 1.  
Figure 1: The work of the image owner.
## 1 Introduction
At present, existing motor reliability test standards conduct accelerated tests under rated and peak conditions, such as GB/T 29,307 and ISO 19,453.4, but they do not consider the coupling of multiple failure modes. This approach is insufficient to reproduce the simultaneous occurrence of multiple failure modes of rotor bridges in the actual operation of users. Developing accelerated test load cycles that cover multiple failure modes and consider lifetime targets during actual user operation is crucial for product reliability evaluation. Therefore, this paper establishes a physical model of magnetic bridge failure based on the actual physical model of the magnetic bridge and its operating conditions. The paper carries out a simulation analysis from electromagnetic, thermal, and thermomechanical coupling fields to determine the location of the rotor danger point. By analyzing the magnetic bridge damage contribution under multi-physical field loading, the dominant failure loads and failure modes are identified. Fatigue tests on the rotor materials are carried out, and life models for the magnetic bridges are established at different temperatures and under alternating speed conditions. Reliability test cycles are constructed from user data to match the actual user loads and determine the damage targets, which contain fatigue aging coupled damage and alternating loads fatigue damage. Finally, an accelerated reliability test load spectrum is developed. The research presented in this paper offers a clear and reliable approach for compiling acceleration test load spectra, which can effectively support the durability assessment of electric motor rotors. This approach is beneficial for improving the efficiency of product development and validation, thereby providing support for the high-quality development of electric motor rotors. Figure 1 illustrates the main technical route in this paper.
# Experimental Study of Compression Behavior on Monolayer FFF Samples
## 1 Introduction
It should be noted that one of the great advantages of the parts obtained with additive manufacturing is the possibility of configuring their deposition trajectories and therefore defining parts with mechanical properties adapted to their requirements in service. In this way, the anisotropy of the parts becomes an advantage. However, this anisotropy can cause problems if it is not controlled, so there are studies that attempt to analyze the behavior of parts obtained with different layer orientations, leading to parts with orthotropic behavior [17,18]. On the other hand, a part where the best compression behavior is required would be one in which the layers are deposited perpendicular to the load [18]. In this way, each of the layers would be oriented in this way and therefore, if the volume of material were the same, the same mechanical strength would be generated. However, it has been seen that there are aspects that affect such as manufacturing parameters or, in another order, geometric parameters. Thus, a part generated with a single layer and oriented in the most favorable way can change its behavior in terms of mechanical resistance. Therefore, studying how geometry affects a single layer of material can help to understand the anisotropic behavior of a part obtained by FDM. In this context, this article addresses properties of great interest that have not been fully studied, as evidenced by the novelty of recently published studies focused on analyzing a single layer of material. At this form, this paper explores the possibility of designing AM monolayer specimens for compression testing for Fused Layer Modeling (FFF) of polylactic acid (PLA). FFF is one of the oldest AM processes and is still very popular both for industrial and hobbyist use. FFF in its basic form produces specimens with a relatively high layer thickness; those of about 0.2-1 mm are common [2, 3, 4, 14, 19]. The high layer thickness facilitates the qualitative and quantitative analysis of the specimen macro-geometrical quality after manufacturing as well as the post-test inspection of the failure mode. In this paper, the compression behavior of single-layer structures is analyzed and confronted with multilayer data obtained from the literature.