esa-sceva/satcom-chunk-collection huggingface dataset:
# On Finding Optimal (Dynamic) Arborescences
## 2 Optimal Arborescences
### Tarjan Algorithm  
The algorithm proposed by [PERSON] [11] is built on the [PERSON] algorithm, but it relies on advanced data structures to become more efficient, particularly in the contraction phase. The algorithm builds in this phase a subgraph \(H=(V,E^{\prime})\) of \(G=(V,E)\) such that \(H\) contains the selected edges. The optimum arborescence could then be extracted from \(H\) through a depth-first search, thereby taking into account Lemma 2 in the [PERSON] paper [11]. This lemma states that there is always a simple path in \(H\) from any vertex \(u\) in a root that is a strongly connected component \(S\) to any vertex \(v\) in the weakly connected component containing \(S\). [PERSON] et al. [12], however, provided a counterexample for this construction, and they proposed a correction that relies on an auxiliary forest \(F\), which we discuss below.  
The algorithm by [PERSON] keeps track of weakly and strongly connected components in \(G\), as well as nonexamined edges entering each strongly connected component. The  
Figure 5: Expansion phase and optimal arborescence. (**a**) Expansion subgraph \(H\) for iteration \(i=3\). (**b**) Expansion subgraph \(H\) for iteration \(i=2\). (**c**) Expansion subgraph \(H\) for iteration \(i=1\). (**d**) Expansion subgraph \(H\) for iteration \(i=0\).  
bookkeeping mechanism used the union-find data structure [23] to maintain disjoint sets. Let SFIND, SUNION, and SMAKE-SET denote operations on strongly connected components, and let WMAKE-SET, WFIND, and WUNION denote operations on weakly connected components. Find operations find the component where a given vertex lies in; union operations merge two components together, and make-set operations initialize the singleton components for each vertex. Nonexamined edges are kept through a collection of priority queues, which are implemented as mergeable heaps. Let MELD, EXTRACT-MIN, and INIT denote the operations on heaps, where the meld operation makes it possible to merge two heaps, the extract-min makes it possible to obtain and remove the minimum weight element, and the initialization operation makes it possible to initialize a heap from a list of elements. We also consider the SADD-WEIGHT operation, which adds a constant weight to all the edge incidents on a given strongly connected component in constant time. Note that edge incidents on a given strongly connected component are maintained in a priority queue, where they are compared taking into account its weight and the constant weight added to that strongly connected component.  
The correction proposed by [PERSON] et al. requires us then to maintain a forest \(F\) and a set rset that holds the roots of the optimal arborescence, i.e., it holds the vertices without incident edges. Each node of forest \(F\) has an associated edge of \(G\), a parent node, and a list of children.
# Energy-Efficient Power Scheduling Policy for Cloud-Assisted Distributed PV System: A TD3 Approach
## 4 Problem Solution  
### Constrained Markov Decision Process  
In this section, the above optimization problem (7) is modeled as a constrained MDP, which is a tuple \(\langle\mathcal{S},\phi,r\rangle\), and the details of each element are described as follows.  
* State: The state consists of two components \(\mathcal{S}=[SOC_{t},C_{t}^{all}]\), where \(SOC_{t}\) is the power state of the energy storage system and \(C_{t}^{all}\) represents the total cost of all parks at the current moment.  
Action: \(\phi\) is the action space that contains the charging or discharging power policy \(\varphi_{i}\in[\varphi_{1},\varphi_{2},\ldots,\varphi_{n}]\), which satisfies \(\varphi_{i}>0\) if the energy storage device chooses to charge, otherwise, \(\varphi_{i}<0\). And \(\varphi_{i}\) is a continuous variable.
* Reward: For each step in the iteration process, the agent will get a reward in a certain state \(\mathcal{S}\) after every possible action in \(\phi\), which should be related to the objective function. Since the objective of our optimization problem is to obtain the minimal sum cost and the purpose of the RL is to obtain the maximum reward, the value of the reward function should be negatively correlated to the total cost. At the same time, to unify the order of magnitude, the immediate reward can be given by \[reward=-\sum_{i=1}^{n}C_{i,t}-punish\] (12) \[punish=\alpha E_{i,t}^{\rm{ess-over}}+\beta E_{i,t}^{\rm{ess-over}}\] (13) where \(\alpha\) and \(\beta\) are the penalty factors, \(E_{i,t}^{\rm{ess-over}}\) and \(E_{i,t}^{\rm{ess-over}}\) are the overcharge and overdischarge of energy storage device, respectively.
# Design of a Spin Test System for Burst Phenomen Considering Nonlinear Rotordynamic Effects
## 1 Introduction
Bearing stiffness values were selected considering the loads in the supports due to permissible unbalance, and thus, non-linear rotor dynamic effects were also included in the calculations. It was also assumed that there was no axis misalignment in the system, and inspections were carried out only for the first engine order. Additionally, since the system is tested under vacuum, there is no aerodynamic damping. In this context, it is only possible to talk about damping of the system. This damping ratio is below 3% and is considered to be negligible in the calculation of the natural frequency. This system damping was used as input data in alternating stress calculations, and an HCF evaluation was made. This study, unlike examples found in the literature, presents a preliminary design for rotordynamics using a discrete model. In this way, the bearing support regions are optimally determined based on the results obtained from DM, which is the first step in the overall system design. Furthermore, instead of assuming constant bearing stiffness values, our study incorporates nonlinearity based on the unbalance force. By selecting bearing stiffnesses depending on the load rather than using constant values in rotordynamic calculations, more accurate computational results consistent with the hummer test can be achieved. As mentioned, the first stage of our study is to build a DM in Matlab Simulink and to calculate the natural frequencies of the system. Following this, a general axisymmetric finite element model was established, and the accuracy of the results obtained from DM was examined in detail using a two-dimensional approach. While the results obtained from DM and the general axisymmetric finite element model are consistent, a three-dimensional finite element model was also created to consider the geometry deviating from axial symmetry and to perform harmonic response analysis. The aim of two-dimensional analysis is the fast verification of DM results because of the low mesh element number. However, harmonic response and related alternating stresses cannot be calculated with this axisymmetric two-dimensional model. As a consequence of this a three-dimensional model was needed. In spin test systems, since the test specimen is tested under vacuum, the absence of aerodynamic damping is assumed, and the damping ratio corresponding to the relevant mode obtained from impact tests has been directly used as input data. The harmonic force generated from the unbalance was given as input data to the 3D finite element model to find the system response. By performing detailed rotodynamic calculations, the test specimen can be brought to the desired rotational speeds while avoiding vibration effects, thus preventing damage to the drive shaft and related components.
# Object-Based Approach for Adaptive Source Coding of Surveillance Video
## 1 Introduction
Many such methods use the mean absolute difference (MAD) of predictive residuals to measure texture coding complexity [8; 9]. Low-level metrics predict frame bitrate allocation recursively by calculating QPs and rate-distortion optimization (RDO). However, such low-level metrics are not robust and are very susceptible to interference due to noisy motion, such as scene changes. High-level metrics use object dynamics (content-driven) to acquire more frame information to calculate frame complexity. To reduce the extra computational complexity of High Efficiency Video Coding (HEVC) intra encoding, a previous study [10] proposed a content-driven adaptive scheme that depends on frame texture and  
Figure 1: Degraded video quality with respect to object and network conditions: (**a**) moving objects with different speeds and (**b**) moving objects with different sizes. combines smaller prediction units into larger units to reduce time complexity. That method can decrease RDO encoding complexity; however, it can only be applied to a single type of partitioning structure. Traditional bitrate control methods are designed with the only goal to fit the network throughput constraint by CBR or VBR, but not with the goal to give constant and reliable video quality for intelligent applications [11; 12]. Considering the video quality degradation with respect to the dynamics of picture complexity, moving objects and wireless networks, constant quality control becomes a more challenging goal. In this paper, a constant quality control method is proposed for surveillance video streaming over wireless networks. We propose an object-based source coding method that adapts the bitrate according to object dynamics relative to size and speed. The relationship between video quality degradation and object dynamics is first analyzed and modeled by a linear system. A set of linear models that correspond to different bitrates is then developed to predict quality reduction relative to bitrate increments. When a moving object is detected, this model predicts the encoding bitrate increment to enhance video quality. A robust estimator is applied to estimate the parameters of the linear regression because of the outliers in the statistical modeling. The remainder of this paper is organized as follows. Section 2 reviews related source coding schemes. The adapted object-based coding method is presented in Section 3. Experimental results are provided in Section 4, and conclusions and suggestions for future work are presented in Section 5.
# Design and Development of a Flexible 3D-Printed Endoscopic Grasping Instrument
###### Abstract  
(1) Background: Interventional endoscopic procedures are growing more popular, requiring innovative instruments and novel techniques. Three-dimensional printing has demonstrated great potential for the rapid development of prototypes that can be used for the early assessment of various concepts. In this work, we present the development of a flexible endoscopic instrument and explore its potential benefits. (2) Methods: The properties of the instrument, such as its maneuverability, flexibility, and bending force, were evaluated in a series of bench tests. Additionally, the effectiveness of the instrument was evaluated in an ex vivo porcine model by medical experts, who graded its properties and performance. Furthermore, the time necessary to complete various interventional endoscopic tasks was recorded. (3) Results: The instrument achieved bending angles of \(\pm\)216\({}^{\circ}\) while achieving a bending force of 7.85 (\(\pm\)0.53) Newtons. The time needed to reach the operating region was 120 s median, while it took 70 s median to insert an object in a cavity. Furthermore, it took 220 s median to insert the instrument and remove an object from the cavity. (4) Conclusions: This study presents the development of a flexible endoscopic instrument using three-dimensional printing technology and its evaluation. The instrument demonstrated high bending angles and forces, and superior properties compared to the current state of the art. Furthermore, it was able to complete various interventional endoscopic tasks in minimal time, thus potentially leading to the improved safety and effectiveness of interventional endoscopic procedures in the future.  
Keywords:endoscopy; endoscopic intervention; 3D printing; endoscopic instruments; minimally invasive surgery; rapid prototyping +
Footnote †: journal: Applied
## Model for Estimating the Modulus of Elasticity of Asphalt Layers Using Machine Learning  
[PERSON] 1, [PERSON] 2,* and [PERSON] 2  
The management of roads, as well as their maintenance, calls for an adequate assessment of the load-bearing capacity of the pavement structure. This serves as the basis on which future maintenance requirements are planned and plays a significant role in determining whether the rehabilitation or reconstruction of the pavement structure is required. The stability of the pavement structure depends on a large number of parameters, and it is not possible to fully assess all of them when making an estimation. One of the most significant parameters is the modulus of elasticity of asphalt layers (E\({}_{\text{AC}}\)). The goal of this study is to use models based on machine learning to perform a quick and efficient assessment of the modulus of elasticity of asphalt layers, as well as to compare the formed models. The paper defines models for E\({}_{\text{AC}}\) estimation using machine learning, in which the input data include the measured deflections and the temperature of the upper surface of the asphalt layer. Analyses of modeling using artificial neural networks (ANNs), support vector machines (SVMs) and boosted regression trees (BRT) were compared. The SVM method showed a higher accuracy in estimating the E\({}_{\text{AC}}\) modulus, with a mean absolute percentage error (MAPE) of 7.64%, while the ANN method and the BRT achieved accuracies of 9.13% and 8.84%, respectively. Models formed in this way can be practically implemented in the management and maintenance of roads. They enable an adequate assessment of the remaining load-bearing capacity and the level of reliability of the pavement structure using non-destructive methods, at the same time reducing the financial costs.
# Local Stiffness Assessment of Geogrid-Stabilized Unbound Aggregates in a Large-Scale Testbed
## 3 Experimental Setup
### Dynamic Cone Penetration (DCP) and Light-Weight Deflectometer (LWD) Testing  
DCP tests were conducted to measure the differences in resistance to penetrating the aggregate layer stabilized with a geogrid and no geogrid. The DCP has a metal cone driven into the aggregate layer by repeatedly striking it with a weight of 8 kg (17.6 lb.) from a drop height of 575 mm (2.26-ft). The penetration after each blow was recorded, and the results were correlated to CBR using an empirical relationship.  
Meanwhile, the composite surface moduli on top of the aggregate base course were measured using an LWD. Six LWD drops, including three seating drops, were used at each measurement point. A Zorn LWD with a falling weight of 5 kg (11 lbs.) and a drop height of 0.375 m (14.8 in.) was utilized. The LWD device placed on top of the testbed is shown in Figure 5a.  
The DCP tests were conducted at three measurement points in the testbed, i.e., Points A to C shown in Figure 5b, while LWD tests were conducted at five measurement points, i.e., Points A to E shown in Figure 5b. The LWD tests were conducted ahead of the DCP tests to avoid any penetration-induced disturbance to the aggregate layer.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**No.** & \begin{tabular}{c} **Confining Pressure** \\ **[kPa]** \\ \end{tabular} & \begin{tabular}{c} **Deviator Stress** \\ **[kPa]** \\ \end{tabular} & \
\begin{tabular}{c} **Bulk Stress** \\ **[kPa]** \\ \end{tabular} &
\begin{tabular}{c} **No. of Load** \\ **Cycles** \\ \end{tabular} \\ \hline Cond. & 103.4 & 103.4 & 413.6 & 1000 \\
1 & 20.7 & 20.7 & 82.8 & 100 \\
2 & 20.7 & 41.4 & 103.5 & 100 \\
3 & 20.7 & 62.1 & 124.2 & 100 \\
4 & 34.5 & 34.5 & 138
## 2 Fatigue Life Prediction
### Total Energy Density-Life Method  
In energy-based methods, the dissipated strain energy per cycle, \(\Delta W_{p}\), is assumed to be the main contribution to the material fatigue damage process. \(\Delta W_{p}\) refers to the area within the hysteresis loop and may be related to the number of reversals to failure, \(2N_{f}\), such that [18]  
\[\Delta W_{p}=\kappa_{p}\Big{(}2N_{f}\Big{)}^{\alpha_{p}}, \tag{4}\]  
where \(\kappa_{p}\) and \(\alpha_{p}\) are two unknowns determined from the experimental data using the least squares method. The model in Equation (4) may provide good predictions for fatigue in high-strength steels. Furthermore, this model becomes advantageous, since the parameter \(\Delta W_{p}\) remains almost constant throughout their lifetime, even for a large range of tempering temperatures, and increasing and decreasing slightly for lower and higher strain amplitude levels, respectively [18; 19; 20].  
In spite of the applicability of the \(\Delta W_{p}\) parameter, this damage parameter is not suitable for longer fatigue lifetimes. To overcome this limitation, the total strain energy, \(\Delta W_{t+}\), is usually considered as the damage parameter instead. \(\Delta W_{t}\), written as  
\[\Delta W_{t+}=\Delta W_{p}+\Delta W_{e+}, \tag{5}\]  
is suitable for both fully-reversed and non-null mean stress conditions. Thus, \(\Delta W_{t+}\) is defined as a sum of the hysteresis energy \(\Delta W_{p}\) and the elastic energy associated with the tensile stress per cycle, \(\Delta W_{e+}\)[21]. The model presented in Equation (5) can be further improved considering the residual fatigue resistance given by parameter \(\Delta W_{0t}\). \(\Delta W_{0t}\) denotes the tensile elastic energy at the material fatigue limit, and then \(\Delta W_{0t}\) becomes the parameter \(\Delta W_{t}\) more sensitive to the mean stress [18; 21; 22]. Equation (5) is now rewritten as  
\[\Delta W_{t+}=\kappa_{t}\Big{(}2N_{f}\Big{)}^{\alpha_{t}}+\Delta W_{0t}. \tag{6}\]  
The parameter \(\Delta W_{t+}\) is almost independent of the strain ratio at a constant strain amplitude [22; 23]. These observations make this approach very desirable for fatigue life analysis in low-cycle fatigue, for both smooth and notched components, because we only need to determine the value of \(\Delta W_{p}\) for the stabilized cycle for a given value of \(\Delta\varepsilon^{t}\)[24; 25; 26; 27].
# Assessment of Drought Severity and Vulnerability in the Lam Phaniang River Basin, Thailand
## 2 Materials and Methods
### Climate Models for Climate Scenarios  
#### 2.3.1 Applicability of GCM Dataset  
The analysis of future climate change was carried out based on future changes in rainfall and maximum and minimum temperatures. The detailed assessment of likely future climate change was then used for sensitivity analysis conducted by the Water Evaluation and Planning System (WEAP model), and an analysis on exposure to the future climate.  
Regarding the analysis of future climate change from 2021-2100, the projections were generated by downscaling the simulations of three Global Climate Models (GCMs), i.e., CNRM-CM5, EC-EARTH, and NorESM1-M, which were obtained from the Coordinated Regional Climate Downscaling Experiment (CORDEX) initiative covering continental Asia at a horizontal resolution of 50 km \(\times\) 50 km. The chosen reference period was 1989-2005, whereas the projections were carried out for 2021-2040, 2041-2060, 2061-2080, and 2081-2100 using two Representative Concentration Pathways (RCPs 4.5 and 8.5) (note: the 20 years projection interval was considered to get a realistic picture of each 20-year future period due to natural variations and anthropogenic increases in greenhouse gas emissions that may cause climate change).
# Estimation and Evaluation of Zenith Tropospheric Delay from Single and Multiple GNSS Observations
## 3 Data Collection  
### GNSS Data  
The IGS established the MGEX to track, collect, and analyze multi-system signals. Nowadays, the MGEX network has developed to over 400 stations with dense distribution, and most stations have the ability to receive signals from multiple GNSS systems. Finally, 55 GNSS stations, as shown in Figure 1, are used in this study, which can track four GNSS systems' signals. The observation data from each station are filtered, and each station is equipped with the capability to track signals from the GPS, BDS, Galileo, and GLONASS. The feasibility of parameters estimation for the single-system is ensured by the fact that each station has more than 80% data integrity and that more than six satellites can be observed for each navigation system. The estimation of tropospheric delay parameters by multi-GNSS is guaranteed to be accurate because of more than 20 observable satellites at each epoch. The redundancy of visible satellites can greatly improve the availability and reliability of estimated parameters.
# An Abstraction Technique for Verifying Shared-Memory Concurrency +
## 3 Formalisation
### Programs
#### 3.3.5 Permission Heaps
\begin{cases}\mathsf{valid_{hc}}(hc_ {2})&\text{if }\ hc_{1}=\mathsf{free}\\ \mathsf{valid_{hc}}(hc_{1})&\text{if }\ hc_{2}=\mathsf{free}\\ \pi_{1}\perp_{\mathbb{Q}}\pi_{2}\wedge v_{1}=v_{2}&\text{if }\ hc_{1}= \langle v_{1}\rangle_{\mathsf{std}}^{\pi_{1}}\wedge hc_{2}=\langle v_{2} \rangle_{\mathsf{std}}^{\pi_{2}}\\ \pi_{1}\perp_{\mathbb{Q}}\pi_{2}\wedge v_{1}=v_{2}&\text{if }\ hc_{1}= \langle v_{1}\rangle_{\mathsf{proc}}^{\pi_{1}}\wedge hc_{2}=\langle v_{2} \rangle_{\mathsf{proc}}^{\pi_{2}}\\ \mathsf{false}&\text{otherwise}\end{cases} \]  
**Disjoint union. ** The following operation defines the disjoint union (i.e., the composition) of two permission heaps. **Definition 21** (Disjoint union of permission heaps). : _The disjoint union \(ph_{1}\uplus ph_{2}\) of any two permission heaps \(ph_{1},ph_{2}\) is defined to be the permission heap \(\lambda v\in\mathit{Val}\,.\,ph_{1}(v)\uplus_{\mathsf{hc}}ph_{2}(v)\), with \(\uplus_{\mathsf{hc}}\) defined as follows._  
\[hc_{1}\uplus_{\mathsf{hc}}hc_{2}\triangleq \begin{cases}hc_{1}&\text{if }\ hc_{2}= \mathsf{free}\\ hc_{2}&\text{if }\ hc_{1}=\mathsf{free}\\ \langle v_{1}\rangle_{\mathsf{std}}^{\pi_{1}+\pi_{2}}&\text{if }\ hc_{1}= \langle v_{1}\rangle_{\mathsf{std}}^{\pi_{1}}\wedge hc_{2}=\langle v_{2} \rangle_{\mathsf{std}}^{\pi_{2}}\wedge v_{1}=v_{2}\\ \langle v_{1}\rangle_{\mathsf{proc}}^{\pi_{1}+\pi_{2}}&\text{if }\ hc_{1}= \langle v_{1}\rangle_{\mathsf{proc}}^{\pi_{1}}\wedge hc_{2}=\langle v_{2} \rangle_{\mathsf{proc}}^{\pi_{2}}\wedge v_{1}=v_{2}\\ \langle v_{1},v_{1}^{\prime}\rangle_{\mathsf{act}}^{\pi_{1}+\pi_{2}}&\text{if }\ hc_{1}= \langle v_{1},v_{1}^{\prime}\rangle_{\mathsf{act}}^{\pi_{1}}\wedge hc_{2}= \langle v_{2},v_{2}^{\prime}\rangle_{\mathsf{act}}^{\pi_{2}}\wedge v_{1}=v_{2 }\wedge v_{1}^{\prime}=v_{2}^{\prime}\\ \mathsf{inv}&\text{otherwise}\end{cases} \]  
Note that \(\uplus_{\mathsf{hc}}\) only gives a non-corrupted entry when applied to two compatible heap cells. Furthermore, free is neutral with respect to \(\uplus_{\mathsf{hc}}\) while inv is absorbing. Below are the most important properties of validity, disjointness and disjoint union. **Lemma 5**. : _(The analogous operations on permission heap cells have the exact same properties. )_  
1. \(ph_{1}\uplus_{\mathsf{ph}}(ph_{2}\uplus_{\mathsf{ph}}ph_{3})=(ph_{1}\uplus_{ \mathsf{ph}}ph_{2})\uplus_{\mathsf{ph}}ph_{3}\)_._
2. \(ph_{1}\uplus_{\mathsf{ph}}ph_{2}=ph_{2}\uplus_{\mathsf{ph}}ph_{1}\)_._
3. _If_ \(ph\uplus_{\mathsf{ph}}1_{\mathsf{ph}}=ph\)_._
4. _If_ \(ph_{1}\uplus_{\mathsf{ph}}ph_{2}\)_, then_ \(\mathsf{valid_{ph}}(ph_{1}\uplus_{\mathsf{ph}}ph_{2})\)_._
5. _If_ \(ph_{1}\perp_{\mathsf{ph}}ph_{2}\) _and_ \((ph_{1}\uplus_{\mathsf{ph}}ph_{2})\perp_{\mathsf{ph}}ph_{3}\)_, then also_ 1. \(ph_{2}\perp_{\mathsf{ph}}ph_{3}\) _and_ 2. \(ph_{1}\perp_{\mathsf{ph}}ph_{2}\) _and_ 2. \(ph_{1}\perp_{\mathsf{ph}}(ph_{2}\uplus_{\mathsf{ph}}ph_{3})\)_._