esa-sceva/satcom-chunk-collection huggingface dataset:
# Grid-Friendly Active Demand Strategy on Air Conditioning Class Load
## 3 Harmonic Suppression Technology  
### Air Conditioning Group Load Operation Characteristics  
The air-conditioning group is nonlinear, so the rectifier circuit is composed of power electronic devices and the multi-motor combination is selected in the system to simulate the operation model. During the peak period of air conditioning working, multiple air conditioners start running at the same time. The load characteristics are shown as the top waveform in Figure 2b; load operation would bring harmonics to the grid, and the current distortion rate generated is very large, up to 14.12%. According to the standards proposed in IEEE Std 929-2000 and IEEE Std. P1547, the control parameters of each odd harmonics and Total Harmonic Distortion (THD) rate in the power system are shown in Table 1. The non-sinusoidal current generated from the air conditioning nonlinear group load is the harmonic source on the utility grid. The voltage drop is generated on the circuit impedance, which is superimposed on the sine wave voltage, resulting in waveform distortion of grid voltage that affects the power quality [18]. Therefore, it is important to monitor and improve the electrical energy characteristics of the air conditioning nonlinear load operation. As shown in Table 1, the 5 th, 7 th, and 11 th harmonic current components are larger, and the 5 th and 7 th harmonics account for 10.22% and 5.34%, respectively, which are less than 4%, meeting the requirements of \(n<\) 11, while harmonic current components of 11, 13 and 17 sum up to 19%, more than 2%, which does not meet the requirements. The total harmonic distortion rate is far beyond the requirements. Since the system only selects several motor models to simulate the nonlinear group load, there is still a large gap compared with the actual large-scale load. If the harmonics are not processed, the consequences are serious. Therefore, it is necessary to monitor the quality of the incoming grid current by THD, and it is necessary to take measures to suppress harmonics and provide high power quality. In Figure 2, FFT harmonic analysis results show that, after APF (active-passive filter) or PF (passive filter) processing, harmonics are suppressed to a certain extent. In the following, the operation principle of PF and APF are analyzed firstly.  
The harmonic current detection method is based on instantaneous reactive power [20], as shown in Figure 3. Three-phase current in the grid are \(i_{a},i_{b},i_{c}\), fundamental current are \(i_{af},i_{bf},i_{cf}\), harmonic current are \(i_{ac},i_{bc}^{*},i_{cc}^{*}\), power voltage is \(e_{a}\). \(C_{pq}\) is a power-current variation matrix, LPF is low-pass filtering, the three-phase grid voltage is converted by C3-2, and is filtered by LPF to obtain a harmonic signal followed by comparing with the fundamental wave.
## 5 Enhancement of Dental Imaging Protocols and Applications
### Imaging-Guided Diagnosis and Treatment Planning
#### 5.2.3 Orthodontics  
Orthodontic treatment planning utilizes CBCT not only for impacted tooth localization but also for analyzing airway dimensions and skeletal symmetry. This extends the technology's role beyond dental alignment into comprehensive craniofacial assessment [35]. Figure 4 shows airway dimensions and bone density, all of which are critical for predicting tooth movement, planning anchorage strategies, and optimizing clinical outcomes.  
Figure 4: CBCT images of a 14-year-old patient used for orthodontic assessment reveal an impacted tooth. (**A**) The panoramic reconstruction illustrates overall dental development and shows the abnormal positioning of the impacted tooth. (**B**) The sagittal view detects buccolingual orientation and proximity to adjacent roots, which may complicate eruption or require root protection during orthodontic movement. (**C**) The coronal slice displays the vertical impaction and spatial relationship with surrounding structures, informing both the anchoring strategy and surgical access. (**D**) The 3D reconstruction provides an integrated spatial assessment, enabling precise localization and facilitating interdisciplinary planning between the orthodontist and oral surgeon. Image courtesy of [PERSON].  
CBCT imaging also enables 3D modeling and treatment simulation, supporting precise planning for clear aligners, bracket placement, and wire adjustments. These tools help to detect issues such as root resorption or bone loss, and enable timely modifications to the treatment plan. In addition, AI-driven technologies improve diagnostic precision by automating measurements, identifying cephalometric landmarks, and generating personalized treatment strategies, streamlining the planning process and enhancing clinical outcomes [36].
# Application of Virtual Reality in Learning Quantum Mechanics
## 5 Conclusions and Suggestions
### Conclusions  
In this study, virtual reality technology was used to develop teaching modules related to quantum mechanics, leading students to further understand the implementation process of famous experiments and increase their learning motivation about physics. Through this research, students' learning effectiveness was investigated by the teaching experiment to understand their performances and views on the virtual teaching modules. The following findings are obtained from the teaching experiment:  
_(1)_ _The virtual teaching modules can improve learning effectiveness._  
The ANCOVA results show that the experimental group using the virtual teaching modules performed better than the control group learned with the traditional teaching method, indicating virtual reality can enhance the learning effectiveness of quantum mechanics. Students can also become more familiar with the experimental process of quantum mechanics after using the virtual teaching modules.  
_(2)_ _The virtual teaching modules incur low cognitive load and high learning motivation._  
The statistical results show that the average score of students' learning motivation is 3.97, approximating the score of \"agree = 4\"; the average score of students' cognitive load is 1.85, lower than the score of \"disagree = 2.\" It is speculated that the immersive and interactive virtual teaching modules can visualize the particles and wave phenomena of electrons and photons to reduce the cognitive load and increase the learning motivation of students in learning the concepts of wave-particle duality.  
_Users were mostly satisfied with virtual teaching modules._  
The questionnaire results on system satisfaction indicate that students had positive feedback about the virtual teaching modules, including learning content, interface design, and system operation. The average score of the questionnaire is 4.39, revealing that students were satisfied with the virtual teaching modules. Most students could understand the relevant knowledge and principles of quantum mechanics and become familiar with the experimental process after using the virtual teaching modules.  
The virtual teaching modules can also be used to solve the calculative tasks in the field of quantum mechanics. For example, in the virtual oil drop experiment, we can calculate the greatest common factor from the charges of different oil drops to determine the basic charge carried by an electron. A similar application can also be found in learning the concepts of special relativity using virtual reality [23], where calculative tasks were performed by adjusting the spacecraft speed to observe the phenomena of time dilation and length contraction and determine the mass-energy equivalence.
## 2 Graph Based Critical Sensor Assessment  
In this section, we show how graph theory can be used to offer a rapid assessment of the critical locations for placing sensors that will provide the high-value information during an emergency evacuation. The two algorithms that we propose rank locations by degree of criticality and use only _a priori_ knowledge solely based on a graph theoretic analysis of the connectivity in a building.  
Note that consistently with our objective of using realistic graph representations of existing buildings, we test both algorithms using a graph modelling the three first floors of the EEE building on the Imperial College London campus. Each floor in this building has a surface area of approximately 1000 m\({}^{2}\).
## 5 Conclusions  
In summary, the use of LIBS together with chemometric methods such as PCA was investigated to demonstrate the viability of the quick analysis of various _Peganum harmala_ seed samples. The various ingredients, including minor, major, and trace elements including Na, H, Li, C, Mg, Ca, Si, Fe, K, Cu, Sr, and Pb, are identified in the seed samples using the LIBS technique. For quantitative study, the CF-LIBS technique subject to optically thin plasma and following LTE was implemented. The laser-stimulated plasma was precisely characterized using the plasma excitation-temperature including the electron number den  
Figure 11: Chemical composition (\(\mu\)g/g) of the _P. harmala_ seed sample-(\(\alpha\)) using the CF-LIBS, XRF, and EDX.  
sity. The elemental analysis using CF-LIBS showed that the C, Mg, and Ca are major, while Na, Li, Si, Fe, K, and Sr are minor elements exist in the samples. In particular, the results presented significant evidence of the relatively lower concentration (\(\upmu\)g/g) of heavy-metals such as Pb and Cu, found in all the samples. Furthermore, PCA was applied to the spectral data achieved by using LIBS to differentiate different _Peganum harmala_ seed samples. The LIBS spectral data variance covered by PC1, PC2, and PC3 was observed as \(\sim\)94.7% of the entire variance. In addition, CF-LIBS results were incorporated with other analytical techniques such as XRF and EDX. The comparative study showed that the elements Mg, K, Si, Ca, Cu, and Fe are identified as major constituent of the _Peganum harmala_ seed samples. Therefore, the results indicates that LIBS in combination with PCA, XRF, and EDX is a fast-growing tool for the identification and discrimination of seed samples compared with other techniques based on chemical methods.  
Methodology, T.A.A. and A.F.; Formal analysis, T.A.A., A.F. and J.I.; Investigation, T.A.A., H.A. and J.I.; Resources, H.A. and A.K.; Writing--original draft, A.F. and H.A.; Writing--review & editing, N.K.P.; Supervision, H.A. All authors have read and agreed to the published version of the manuscript.  
The authors extend their appreciation to the Deputyship for Research & Innovation, Ministry of Education in Saudi Arabia for funding this work through the project number RI-44-0129.  
Not applicable.  
The data is available on request.  
The authors declare no conflict of interest.
# Ship's Digital Twin--A Review of Modelling Challenges and Applications
## 4 Applications
### Various Applications  
Modelling a ship's power system to increase the overall efficiency was studied in [18], demonstrating an improvement in response time and false blackout detection. Operating costs were reduced by the proposed long- and short-term generator load distribution optimisation, which resulted in 6% to 8% fuel savings and lower maintenance costs. The propulsion system was optimised to reduce its impact on the bus-bar frequency by predicting disturbancesand thus power fluctuations via the proposed quasi-static load limiting controller based on real-time measurements. Power redistribution control was proposed to mitigate voltage and frequency fluctuations that dynamically affect thrusters and other large consumers, drastically improving grid stability without affecting the response of the ship.  
In [10], a novel approach was proposed to develop a DT model for voyage performance evaluation by predicting ship speed and fuel consumption of a bulk carrier where AIS data and noon reports were expanded with weather hindcast data. The developed model was validated, thus consequently enabling the basis for GHG (greenhouse gas) emissions reduction as the ship speed, fuel consumption, and GHG emissions are correlated. As the proposed modelling approach did not include sensor-collected data, it can be applicable on various ships and, in the case of a fitted sensor network on-board, could be further expanded.  
When designing a DT, as in any modelling, a compromise must be made between the complexity and real-time performance. The paper [15] proposed a modelling approach of a marine diesel engine that satisfies that compromise. The proposed model outperformed the differential equation model based on the Runge-Kutta method in terms of calculation speed, while acquiring low relative error values during HIL experiments in the validation procedure on a marine diesel engine test-bed, thus making it a basis for anomaly detection, failure mode management problems, tracking thermal efficiency, and emissions prediction.  
In addition to the aforementioned purposes, ref. [21] proposed a DT concept for the purpose of real-time sensor data reconstruction and error detection and correction, thus validating and correcting data acquired from the heat exchanger system. The method proposed in [21] offers a wide range of applications and is not limited to heat exchanger systems.  
In [27], a DT model of a boost converter as part of a shipboard power system was proposed. The paper dealt with problems in grey-box parameter identification methods rather than focusing on the application purpose, thus comparing two algorithms for minimising the error between the predicted and measured values. As a result, further work was been proposed to investigate the best global optimisation algorithm used for parameter fitting.
# Infrared Dim and Small Target Detection Based on the Improved Tensor Nuclear Norm
## 7 Summary  
To reduce the interference caused by the strong edge contour background and the high level of noise present in the process of infrared dim and small target detection, the model presented in this paper further processed the structure tensor information based on the IPT model, combining local features with global features. This was done by establishing a new anisotropic background feature weight function to describe the background feature information, achieving the suppression of strong edge contours in the structure tensor. Secondly, an improved high-order cumulative target local saliency region discrimination model was proposed to perform energy enhancement on the saliency targets in the structure tensor; finally, energy enhanced structure tensor information was introduced into the PSTNN model as a weight matrix for decomposition to obtain the final target signal. Through experimental verification, the signal-to-noise ratio and background suppression factor of the algorithm in this paper are above 14 and 424, respectively, in different scenes; it is known by the ROC curve that the detection rate of the algorithm in  
Figure 15: (**a–f**) represents the ROC curves for the ten algorithms under six scenarios.  
this paper reaches \(1\) after the false alarm rate of 0.3 in six scenes. Compared with other advanced algorithms, the algorithm in this paper outperforms other algorithms in all three evaluation indexes, so the algorithm in this paper is effective.  
Conceptualization, A.W. and X.F.; methodology, A.W., X.F. and Q.H.; software, A.W., X.F. and Q.H.; validation, A.W.; formal analysis, A.W., H.C., X.F. and Q.H.; investigation, A.W., X.F. and Q.H.; resources, X.F. and Q.H.; data curation, A.W.; writing--original draft preparation, A.W. and X.F.; writing--review and editing, A.W., X.F., H.C., Q.H. and Z.X. All authors have read and agreed to the published version of the manuscript.  
This work was partially supported by the National Natural Science Foundation of China under grant 62001129, the Guangxi Natural Science Foundation (2021 GXNSFBA075029), the National Natural Science Foundation of China under grant 12174076, and the Guangxi Natural Science Foundation (2021 GXNSFDA196001).  
Infrared raw images from [[https://doi.org/10.11922/sciencedb.902](https://doi.org/10.11922/sciencedb.902)]([https://doi.org/10.11922/sciencedb.902](https://doi.org/10.11922/sciencedb.902)), accessed on 26 April 2022.  
The authors declare no conflict of interest.  
The following abbreviations are used in this manuscript:  
\begin{tabular}{l l} Aadcdd & absolute average difference weighted by cumulative directional derivatives \\ GST & Generalized-structure-tensor \\ VNTRF & via non-convex tensor fibered rank \\ FKRW & facet kernel and random walker \\ MPCM & multiscale patch-based contrast measure \\ SRWS & self-regularized weighted sparse \\ PSTNN & partial sum of the tensor nuclear norm \\ \end{tabular}
## 4 Experimental Setup
### Research Questions  
* RQ1: How much can HS-based parameter optimization improve SDP performance in maritime domain software?
* RQ2: By how much can HS-based parameter optimization method reduce cost?
* RQ3: Which parameters are important for improving SDP performance?
* RQ4: How does the proposed technique perform in Open Source Software (OSS)?
## 4 Simulation and Performance Evaluation
### Pre-distributed keys  
We evaluated the performance of the proposed framework for the pre-distributed keys mechanism. The key distribution time, memory usage, energy consumption, and scalability of the framework were evaluated for different numbers of sensor nodes in the network. The results of the evaluation are shown in Figure 5.  
As shown above the key distribution time, memory usage, and energy consumption increase with an increase in the number of sensor nodes in the network. However, the proposed framework exhibits good scalability for up to 150 sensor nodes in the network.
## 2 Materials and Methods
### The Remediation Process of Different Methods  
To evaluate the effects of various Pb remediation methods on ARGs in soil, each method was applied for 45 days across all control and experimental groups (Figure 1). \"Invite\" referred to PS2.5 treated with montmorillonite. \"MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\)\" denoted PS2.5 remediated with a composite of MgO and Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\). \"Invite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\)\" indicated PS2.5 remediated with a composite of montmorillonite, MgO, and Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\). \"BES\" expressed PS2.5 remediated with Bess. \"BES-Invite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\)\" represented PS2.5 treated with a combination of these composite agents and BES. To assess the impact of initial Pb concentration and pH on ARGs during synergistic remediation with BES and composite agents, four additional experimental groups were established. \"BES5-Imvite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\)\" and \"BES10-Invite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\)\" represented PS5 and PS10, respectively, after synergistic remediation. pH adjustments were made using 1 mol/L HNO\({}_{3}\) and 1 mol/L NaOH. \"BES-pH5-Imvite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\)\" and \"BES-pH9-Imvite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\)\" denoted PS2.5 with initial pH adjusted to 5 and 9, respectively. All remediation systems involved treating Pb-contaminated soil with a remediation agent at 10% of the soil mass, with composite agents mixed in a 1: 1 mass ratio. The BES reactor, detailed in Figure 2, consists of three identical plexiglass cubes (6 cm \(\times\) 6 cm \(\times\) 6 cm) with a total height of 19 cm and a width and length of 6 cm. The reactor was divided into upper, middle, and lower layers. Carbon brushes served as anodes throughout all layers, while the cathode comprises graphite felt-activated carbon, including a catalytic layer, graphite felt collector, and PTFE diffusion layer [24].  
Figure 2: Configuration diagram of the BES reactor.
# Synthesis and Structural Confirmation of the Thiazole Alkaloids Derived from _Peganum harmala_ L.
## 3 Results and Discussion  
As shown in Scheme 1, the syntheses of **1** and **2** commenced with decarboxylative aldol condensation between syringealdehyde **4** and diethyl malonate to yield ethyl cinnamate **5**. Hydrogenation of **5**, using palladium on activated carbon as a catalyst, quantitatively afforded ethyl propionate **6**, which was subjected to benzyl protection to provide benzyloxyphenylpropamate **7**. With **7** in hand, several sets of synthetic routes were investigated for the synthesis of \(\alpha\)-bromoaldehyde **3**, a key intermediate in Hantzsch thiazole synthesis. When propane **7** was fully reduced to propanol **8** using lithium aluminum hydride (LAH), followed by oxidation using Dess-Martin periodinane (DMP), propanal **9** was readily obtained in high yield. The \(\alpha\)-Bromination of slightly unstable propanal **9** using 5,5-dibromomeldrum's acid and concentrated HCl, afforded \(\alpha\)-bromoaldehyde **3** in the best yield (60%). The Hantzsch thiazole synthesis of \(\alpha\)-bromoaldehyde **3** using thioformamide or thioacetamide, provided 2\(H\)-thiazole **10** and 2-methylthiazol **11**, respectively, in moderate yields. The debenzylation of benzyloxybenzenes (**10** and **11**) using titanium tetrachloride readily afforded the desired 2,6-dimethoxyphenols (**1** and **2**) in moderate yields (60% and 69%, respectively). The spectral data of synthesized **1** and **2** (see Tables S1 and S2 in the Supporting Information) were identical to those previously reported for peganumal A and B, respectively.