esa-sceva/satcom-chunk-collection huggingface dataset:
# A Study of Emergency Aircraft Control During Landing
###### Abstract  
This paper addresses the problem of loss of control during flight caused by failures of flight control surfaces. It presents a study of an emergency thrust control system based on linear-quadratic control with integral action. The research encompasses an analysis of thrust modulation control characteristics, a review of existing control systems, and a detailed description of the development process, including the research platform configuration, identification of the aircraft state-space model, control law design, integration of system components within the MATLAB and Simulink environment, and software-in-the-loop testing conducted in the X-Plane 11 flight simulator using a Boeing 757-200 model. The study also investigates the issue of control channel cross-coupling and its impact on simultaneous control of the aircraft's longitudinal and lateral dynamics. The simulation results demonstrate that the proposed emergency system provides adequate controllability, with settling times of approximately 12 s for achieving a flight path angle setpoint of +5\({}^{\circ}\), and 13 s for attaining a maximum (limited) roll angle of 20\({}^{\circ}\), achieved in separate manoeuvres. Furthermore, simulated landing attempts suggest that the system could potentially enable successful landings at approach speeds significantly higher than standard recommendations. However, further investigation is required to address decoupling of control channels, ensure system stability, and evaluate control performance across a broader range of aircraft configurations.  
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Azerbaijan Airlines' Embraer 190-100 IGW on 25 December 2024, where hydraulic controls were lost after the aircraft was struck by a surface-to-air missile and crashed on an attempted emergency landing at Aktau International Airport, Kazakhstan, an additional 38 fatalities were recorded [3].  
Such failure scenarios involve several critical factors:  
* Phugoid motion (long-term pitching oscillations).
* Slow aircraft response to thrust changes.
* High pilot workload.
* Significant difficulty in maintaining an approach path during landing.
* Lack of airspeed control in an event of total hydraulic failure.  
These considerations justify the development of a thrust-based control system that would enable safe flight and landing of an aircraft deprived of other control capabilities. Such a system should be simple to implement on existing machines, requiring only modifications to the flight control computer (FCC) software, without changes to engine control computers or cockpit instrumentation.  
This paper is structured as follows:  
* Section 2 presents a literature review;
* Section 3 describes the proposed solution;
* Section 4 outlines the research environment;
* Section 5 discusses the identification of the aircraft model;
* Section 6 details the design of the control system;
* Section 7 presents simulation test results of the emergency control system conducted in the X-Plane 11 flight simulator;
* Section 8 summarises the study;
* Section 9 outlines future development plans for the system.
## 6 Analysis and Results
### EMCR Evaluation
#### 6.2.1 EMCR over Different Cache Times  
We exploit our proposed EMCR protocol to investigate the impact of the SCF mechanism on the network performance in terms of packet delivery ratio (PDR), total throughput, normalized routing overhead (NRO), end-to-end delay, and energy consumption. We vary the cache time to hold the packets for 2 s, 5 s, or 10 s. Additionally, we vary the average vehicle speeds, from 15 to 75 Mph in the hybrid network of VANET-WSN.  
PDR is shown in Figure 6 and the throughput is shown in Figure 7. They are decreased by increasing the average vehicle speeds, but increasing the cache time increases the PDR and throughput. NRO is shown in Figure 8. Based on the definition of this metric, an  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Network area & 2000 m \(\times\) 2000 m \\ Mobility model & Manhattan \\ Mobility generator & SUMO \\ Traffic rate & CBR, 512 bytes \\ Simulation time & 100 s \\ \hline \hline \multicolumn{2}{c}{Wireless Sensors Network} \\ \hline Number of wireless sensors & 185 \\ Transmission range & 150 m \\ MAC specification & IEEE 802.11b \\ Physical rate & DSSS, 1 Mbps \\ Propagation model & Nakagami \\ Initial energy & Random [0, 1000] Joule \\ \hline \multicolumn{2}{c}{Vehicles} \\ \hline Number of vehicles & 15 up to 100 \\ Transmission range & 500 m \\ MAC specification & IEEE 802.11p \\ Physical rate & OFDM, 6 Mbps, 10 MHz \\ Propagation model & Nakagami \\ \hline \hline \end{tabular}
\end{table}
Table 1: Simulation settings in urban scenariosincrease in the PDR causes a decrease in the routing overhead. Therefore, NRO is increased with the increasing average vehicle speeds, but is decreased with the increased cache time.  
Figure 9 shows the average end-to-end delay, including the total amount of average buffering delay (Store/Carry-Forward delay), and the average transmission delay (forwarding delay) of all successfully delivered packets. Therefore, the average end-to-end delay is increased by the increased average vehicle speeds and increased cache time. As  
Figure 8: Normalized routing overhead vs. 2 s, 5 s, 10 s Cache Time and Average Vehicle Speed (Mph).  
Figure 6: Packet delivery ratio vs. 2 s, 5 s, 10 s Cache Time and Average Vehicle Speed (Mph).  
Figure 7: Throughput vs. 2 s, 5 s, 10 s Cache Time and Average Vehicle Speed (Mph).
## 3 Results  
### Dynamics of Vegetation Greenness and Productivity  
Vegetation greenness showed an upward trend in the three agglomerations from 2001 to 2020 (Figure 2). Specifically, the PRD experienced a remarkable 32.22% increase in vegetation greenness, while BTH experienced a 27.71% growth. In contrast, the YRD displayed a more modest growth rate of 6.90%, with its average LAI increasing from 1.27 to 1.34. There was also an obvious spatial heterogeneity in vegetation greenness changes within each agglomeration (Figure 2). Notably, the proportion of regions experiencing significant greenness growth exceeded 50% in both BTH and PRD, while in the YRD, this proportion was 37.26%. Conversely, regions experiencing significant greenness decline were relatively limited, accounting for 5.00% and 3.61% of the total area in the PRD and BTH, respectively, but reaching 15.72% in the YRD. Overall, the extent of regions experiencing significant greenness growth outweighed those with insignificant growth, and there were fewer regions with significant decline than those with insignificant decline across three agglomerations.  
Vegetation productivity showed an upward trend in the three agglomerations from 2001 to 2020 (Figure 3). Specifically, BTH experienced a remarkable 51.46% increase over this period. In the PRD, productivity showed an 18.30% increase. And productivity increased by 10.82% in the YRD. Spatial heterogeneity was also evident in the changes in productivity within each agglomeration (Figure 3). Notably, the proportion of regions experiencing significant productivity growth exceeded 50% in all agglomerations. Conversely, the proportion of regions with a significant productivity decline was relatively small, at 0.79%, 2.70%, and 7.01% in BTH, PRD, and YRD, respectively. Overall, the regions experiencing significant growth in productivity outweighed those with insignificant growth, while there were fewer regions with a significant decline than those with insignificant decreases across three agglomerations.  
Figure 2: Dynamics of vegetation greenness from 2001 to 2020.
## 4 Experimental Results
### Implementation Details  
This study considers the Northeastern University (NEU) [10] surface defect detection dataset. This dataset is a collection of defects on hot-rolled steel strips, consisting of the following six defects: pitted surface, inclusion, patches, rolled-in scale, crazing and scratches. This dataset includes 360 image samples for each defect, respectively.  
The parameters were set for various models used in the experiment. The RetinaNet model used a pre-trained model with weights, with the number of anchor boxes as nine, the learning rate \(10^{-5}\). The backbone used in RetinaNet is ResNet50, and the model is executed for 50 epochs. In the UNet model, the learning rate parameter is set to a \(10^{-2}\) value, and the model is executed for 300 epochs. The XGBoost classifier is supported by stochastic gradient boosting. It has a parallel computing environment. The classifier has two types of boosters, gbtree and linear. The classifier in this study uses a gbtree booster. The total number of trees in this booster is 100, and each level of tree size is 6. These trees are constructed parallelly, which is supported by the block structure feature of the algorithm. The classifier performs multi-classification, with multi-softmax probability as the optimization objective.  
An evaluation metric is a standard for measuring or evaluating the performance and efficiency of ML and deep learning models. There are various evaluation metrics accessible according to the models and the conditions to be satisfied. Among all the available metrics, we adopted confusion matrix (CM), AP and mAP [50]. The CM is a matrix of form MxM. This evaluation metric is introduced in the classification phase of the proposed approach, where the defects are classified into one of the six classes of defects. So, the CM is of 6 \(\times\) 6 size in this study and depicts six classes of defects. The general representation of the CM is shown in Figure 4.  
In this study, the AP and mAP for evaluation of the steel surface defect detection are used [51]. The AP is calculated from the graph plotted between precision and recall values. We can obtain the AP using Equation (1), which is as follows:  
\[\text{AP}=\sum_{k=0}^{k=n-1}[R(k)-R(k+1)]*P(k) \tag{1}\]  
where \(n\) is the number of thresholds, \(R\) is recalls and \(P\) is precisions.  
The precision and recall are computed by the Equations of (2) and (3), respectively.  
\[\text{Precision}=\frac{\text{TP}}{\text{TP}+\text{FP}} \tag{2}\]  
\[\text{Recall}=\frac{\text{TP}}{\text{TP}+\text{FN}} \tag{3}\]  
Figure 4: Confusion matrix representation. TP = true positive, FP = false positive, FN = false negative and TN = true negative.  
The mAP is the mean of all the AP calculated for the individual classes.  
\[\text{mAP}=\frac{1}{c}\sum_{k=1}^{k=c}\text{AP}_{k} \tag{4}\]  
where \(\text{AP}_{k}\) is the average precision of class \(k\) and \(c\) is the number of classes.
## 1 Introduction
### Organization of This Manuscript  
In the next section, we present a brief state of the art and discuss relevant approaches in the field. Next, Section 3 presents our approach, including the underlying mathematical model and the data set employed for training and evaluation. Section 4 details the process for estimating the model parameters. Section 5 presents the performance evaluation. Finally, the conclusion is stated in Section 6.
## 7 Estimating the Confusion Matrices of GEVA and GEFA
### GEFA Confusion Matrices  
As previously explained, GEFA is formed by two third-party software packages: SHORE and CERT. As already said, using the recorded visual information obtained from the experiments, the confusion matrices for both packages are calculated and shown in Table 2.  
Again, it can be observed that SHORE is quite precise at detecting the happiness (100%) and the surprise (80%) emotions. On the contrary, it does not work so well when detecting the neutral (66%) and sad (55.55%) ones, although these values are not really poor. In this case, _the calculated average success rate for SHORE is 75.55%._  
In relation to CERT, as can be observed, this package is very accurate at recognizing happiness (100%) and the neutral (85.71%) emotions and not so precise when detecting sadness (28.57%) and surprise (36.36%). Finally, _the calculated average success rate for CERT is 62.66%._  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Happy** & **Neutral** & **Sad** & **Surprise** \\ \hline
**SHORE** & **Happy** & 100 & 0 & 0 \\
**Neutral** & 0 & 66.66 & 16.66 & 16.66 \\
**Sad** & 0 & 22.22 & 55.55 & 22.22 \\
**Surprise** & 0 & 10 & 10 & 80 \\ \hline \hline \end{tabular}
\begin{tabular}{c c c c c} \hline \hline  & **Happy** & **Neutral** & **Sad** & **Surprise** \\ \hline
**Happy** & 100 & 0 & 0 & 0 \\
**Neutral** & 0 & 85.71 & 14.28 & 0 \\
**Sad** & 0 & 71.42 & 28.57 & 0 \\
**Surprise** & 9.09 & 54.54 & 0 & 36.36 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Confusion matrices for Gender and Emotion Facial Analysis (rows: real emotions; columns: detected emotions).  
As mentioned in Section 6.1, during the experiments, we observed that the considered software packages are not reliable when the user is speaking. When this happens, the outputs of these packages fluctuate between different emotions.
## 6 Conclusions  
1. The proposed S-L analysis method improved the traditional static frequency characteristic of the analysis method and it can qualitatively and quantitatively analyze the frequency regulation process (including primary frequency regulation and secondary frequency regulation) of input/output bidirectional devices and complex multi-power supply systems under different control strategy regardless of the operation mode (generator mode or motor mode).
2. A distributed PV storage virtual synchronous generator system was established through the design and control of bidirectional DC-DC (chopper) and bidirectional converter. This kind of system can operate in a stable way in generator/motor dual mode with the bidirectional frequency regulation capability and the inertia characteristic of the synchronous generator, which satisfies the requests of State Grid Corporation of China (SGCC) and the autonomous power system.
3. In order to mimic the actual microgrid characteristics accurately, a Synchronous Machine Grid Equivalent Model was designed. Additionally, for the purpose of realizing the compatibility between devices with inertia such as synchronous generators and virtual synchronous generators, an inertia matching method was proposed, which contributed to the stable operation of microgrid.
4. The feasibility and correctness of the proposed PV storage virtual synchronous generator system, the S-L analysis method and the inertia matching method were verified through simulation experiments.  
This paper was supported by National Key R&D Program of China (2016 YFB0900400); Natural Science Fundings of Hebei Province (E201502046); State Grid Corporation of Science and Technology Project (PD71-17-008), Liaoning Power Grid Corporation's 2018 Science and Technology Project \"Research on the Reactive Power and Voltage Optimization Strategy and Evaluation Index Considering Source and Load Fluctuation Characteristics\".  
[PERSON] proposed the research direction and the idea of S-L analysis method. [PERSON] completed the S-L analysis method. [PERSON] proposed and designed the Synchronous Machine Grid Equivalent Model. [PERSON] and [PERSON] established the mathematical model of PV storage virtual synchronous generator system. [PERSON] studied the matching method of inertia. [PERSON], [PERSON] and [PERSON] performed the verification. [PERSON], [PERSON] and [PERSON] analyzed the result together. [PERSON] wrote the paper.  
The authors declare no conflict of interest.
# Recoil Control of Deepwater-Drilling Riser with Optimal Guaranteed Cost \(H_{\infty}\) Control
###### Abstract  
In deepwater-drilling engineering, it is necessary to disconnect the bottom equipment of the lower marine-riser package from the blowout preventer when encountering multi-hazard environmental factors. In order to reduce the impact of recoil on the drilling platform after the sudden disconnection of the riser, in this paper, an optimal guaranteed cost \(H_{\infty}\) recoil control problem is considered for the drilling riser. First, a three-element mass-damper-spring deepwater-drilling riser model subject to fluid discharge and heave motion of offshore platform is given. Then, an optimal guaranteed cost \(H_{\infty}\) controller (OGCHC) is designed to suppress the recoil response of the drilling riser, and the sufficient conditions for the asymptotic stability of the closed-loop system are derived. Third, it is found through simulation results that the designed OGCHC can reduce the recoil response effectively. In order to further analyze the advantages of the OGCHC, the performance indices of the riser without active-recoil control and with optimal control (OC) and OGCHC are compared. It is shown that the average response amplitudes of three mass blocks of the riser are almost the same, while the control cost by the OGCHC is less than that by the OC. Further, under the designed recoil control, no riser compression occurs, thereby ensuring the safety of the riser system.  
multi-hazard; drilling riser; mud discharge; recoil control; guaranteed cost control; vibration control +
Footnote †: journal: Applied  
Acticle  
Recoil Control of Deepwater-Drilling Riser with Optimal Guaranteed Cost \(H_{\infty}\) Control  
[PERSON]  
1 College of Automation and Electronic Engineering, Qingdao University of Science & Technology, Qingdao 266061, China; [EMAIL_ADDRESS] (Y.-T.S.); [EMAIL_ADDRESS] (Y.-D.Z.); [EMAIL_ADDRESS] (W.Z.)
# Design and Evaluation of Flooding-Based Location Service in Vehicular Ad Hoc Networks+
## 2 Related Work
### Density-Aware-Map-Based Location Service (DMBLS)  
The DMBLS [14] is a location service protocol where the network zone is divided into a hierarchy of regions. A region is a network zone with high traffic density, and all the location servers are chosen in this region. In this protocol, queries from vehicles are forwarded to the higher levels until the required information is found and sent back to the client. The performance of this protocol is highly dependent on the choice of region, especially when considering the changing characteristics of traffic during different periods of the day.
## 4 Factors Influencing the Phytochemical Compounds of _Brassica_ Vegetables
### Environmental and Agricultural Factors
#### 4.2.1 Cultivation System and Soil Composition  
The cultivation system influences the quality of vegetable product, in particular the concentration of primary and secondary metabolites in _Brassica_ vegetables.  
Some authors reported a higher antioxidant (phenolic compounds, in particular flavonoids) and GLS concentration in _Brassica_ growth in organic cultivation system than in conventional systems [128], as demonstrated in early harvested trenchuda cabbage [129]. This result could be linked to the fact that, under organic cultivation, crops are subjected to more biotic and abiotic stress; these stressing conditions lead to an increase in the production of secondary metabolites as a defence mechanism, and consequently obtaining vegetables with higher nutritional and antioxidant potential than in a conventional system.  
Several studies described an opposite situation and contrasting evidence about phytochemical enhancement in organic vegetables [130; 131]. In fact, [PERSON] et al. [132] reported that the choice of cultivation systems does not modify the antioxidant properties of raw and processed products, but differences can be found in the chlorophyll and carotenoid contents of organic \"cima di rapa\" landraces. The lipophilic antioxidant content was improved in organic product while the hydrophilic component, which constituted 99% of the total antioxidant capacity, was not affected by the different crop management in \"cima di rapa\". However, the organic system influenced the quality of products during storage: after 7 days of storage at 5 \"C, the organic \"cima di rapa\" maintained the best colour with high chlorophyll levels, probably due to a higher availability of nitrogen in organic management; on the contrary, the quality declined with a higher production of strong off-odour after 14 days of storage, in comparison to the conventional products.  
Regarding the soil composition effect on _Brassica_ quality, it was reported that the highest GLS and phenolic compounds content were detected in locations with the highest soil pH and available potassium; the content can be also influenced by nitrogen and sulphur applications in turnip [104]. On the contrary, in _B. rapa L. Subsp. Sylvestris_, flavonoids (kaempfer and quercetin derivatives) were reduced by sulphur availability [113].
# Study on the Increase of the Supporting Capacity of a Cement Milk Pile with Expansive Additives
## 3 Results and Discussion
### Economic Feasibility  
To examine economic feasibility, it was assumed that 100 round steel pipe piles (10 m long, design load of 123 ton/each) were constructed using the bored pile method with DH508 drilling equipment, a T4 mounting auger (18.5 m long) and casing (6.5 m long) in strata composed of a buried layer (1.5 m thick), sedentary deposit (6.5 m thick), and weathered layer (5 m thick). In KS F 4306 standard, the material and labor costs, cost required for the construction of 10 m long piles and buried piles among 5-15 m round steel pipe piles produced for piles, and the input construction cost were calculated. Construction costs included processes such as drilling, hydraulic driving, floating soil treatment, head clearance, and remnant crushing. The required material cost was set as low as possible by comparing price data, price information, and transaction prices from the Ministry of Strategy and Finance of Korea. Equipment and operating costs were set on the basis of the standard estimating from Korea Institute of Civil Engineering and Building Technology.  
Figure 6: Porosity and total pore area.  
Figure 7: Comparison of incremental intrusion vs. pore size in specimens according to the W/B ratio and expansive addition content.  
Figure 8 shows the pile reduction/mixing ratios and total construction costs for 100 10 m steel pipe piles. Considering the 66-97% share of the skin friction force to the total bearing capacity of the pile (as noted in previous studies), expansive additives can be expected to reduce the number of piles required for foundation design due to increased frictional resistance [13]. In particular, the W/B of 83% showed a large increase in frictional resistance, and when 5% expansive additive was mixed in, the number of required piles was reduced by 4.25% to 6.24%; when 10% expansive additive was mixed in, the required number was reduced further to \(\sim\)23.70-34.84%. When costed out, the 10% expansive additive mix provided a greater cost reduction effect than the 5% mix (i.e., the former mix could reduce total construction costs by up to 33.24%), demonstrating the greatest economic feasibility.