esa-sceva/satcom-chunk-collection huggingface dataset:
## 6 Conclusions  
This paper presents the design and development of a GNSS passive radar for the classification of lands, based on the water content feature, and the detection of water surfaces' extent and scattering objects on the ground. Such GNSS passive radar is intended for small UAVs; therefore, size and weight constrained the design of the whole system from the beginning. The sensor features four synchronized RF channels, which are used to receive the direct and the reflected GNSS signals separately over RHCP and LHCP polarizations. The RF part is connected to a commercial embedded micro-processor, which hosts the software routines to control the flow of the digital samples of all channels. The sensor guarantees the storage of more than 30 min of data, if the sampling frequency of the signals is set to 13 MHz. Although the sensor has been integrated with low-cost COTS components, the design followed the software radio paradigm and, for this reason, allows for a significant level of flexibility of the system settings, e.g., the possibility to use only a subset of the four channels, custom frequency plan and variable bandwidths. The sensor has been intensively tested in-lab and validated through some flight tests. These served to assess the performance in a real environment, including the electromagnetic compatibility with other UAV devices, the sensor reliability to store data in an automatic fashion and the mechanical resistance of the sensor's case during take-off and landing stress. The sensor successfully demonstrated its ability to receive reflected signals, both LHC and RHC polarized. This result is comparable to others presented in the literature, but on the one hand, it allows the simultaneous grabbing of RHCP and LHCP reflections and, on the other hand, has been obtained with a prototype much lighter and smaller with respect to those used in other experiments.  
Among all of the results, it is important to underline the lesson learned from the analysis performed over some of the collected datasets. The cross-polarization isolation between the RHCP and LHCP channels of the antenna pointing at the nadir is critical for the system performance. In fact, if the cross-polarization rejection is lower than the minimum required, a portion of the LHCP power obscures the RHCP reflected signals, which cannot be correctly measured. This limits the fine computation of correct soil moisture parameters and identifies the nadir-pointing dual-polarization antenna as the most critical system element, as it requires very high cross-polarization isolation, typically unavailable as COTS.  
Furthermore, considering the extreme weakness of the reflected signals, another critical point is the accurate characterization, calibration and control of the electromagnetic environment during the tests and on-board the aircraft during the data collections: the effect of the electromagnetic interference from the surrounding electronic systems during the data collections, especially on-board unmanned vehicles, can be destructive for the GNSS-R processing and, therefore, must be carefully controlled.
## 1 Introduction
Thus, related work has also been continuing in more regional refined studies, such as the simplified ionospheric regional model (SIRM) [26] and its improved version [25] over Europe, the regional ionospheric model over Antarctica [27], the regional ionospheric model over India [28], the maps over northern China [24], as well as others [29]. The accuracy of the derived parameters in above-mentioned applications directly depends on the accuracy of \(f_{0}\)F\({}_{2}\)[4]. Therefore, the empirical ionospheric model has been continually improved and further developed by different groups in the public domain making use of the latest measured data [8; 19] or introducing advanced techniques, for instance, artificial neural networks [22] and EOF analyses [23; 30; 31]. A clear trend is evident in focusing on regional models, rather than global models during the past decades, because of their capability to produce a more accurate ionospheric representation over particular areas giving better results for both telecommunications and geophysical modeling [25; 32; 33]. The ionosphere over East Asia is an important region where the atmospheric dynamics within the high, middle, and low-latitude ionosphere, can be very complicated. Several studies have shown that there are relatively large discrepancies in the values of the ionospheric parameters predicted by the IRI model and the observational data in equatorial and low-latitude regions, especially in East Asia and areas of southern China [23; 34]. Therefore, this paper focuses on reconstructing a simplified regional long-term prediction model for \(f_{0}\)F\({}_{2}\) over East Asia. In addition, an important objective in this modeling is to simplify the algorithmic complexity and to improve model efficiency based on the basis of guaranteeing accuracy. In this paper, the proposed model is represented as a numerical mapping using the orthogonal temporal and spatial functions. Most importantly, the temporal numerical map functions are reconstructed through two solar activity parameters (F10.7 and sunspot number), and the spatial numerical map functions are reconstructed by the modified surface interpolation method based on the geomagnetic function instead of the simple geographic coordinates. In the following sections, we will describe the modeling approach in Section 2, and then the model reconstructed process in Section 3. In the end, the predicted values of the new model will be compared with the measured values and IRI model to validate its effectiveness.
# Application of Machine Learning Techniques to Predict a Patient's No-Show in the Healthcare Sector
###### Abstract
The open database is available on the Kaggle ([[https://www.kaggle.com/joniarroba/noshowappointments](https://www.kaggle.com/joniarroba/noshowappointments)]([https://www.kaggle.com/joniarroba/noshowappointments](https://www.kaggle.com/joniarroba/noshowappointments)), accessed on 25 November 2021) platform and refers to medical appointments scheduled in public hospitals in the city of Vitoria, in the state of Espirito Santo, Brazil. The downside of this dataset is the lack of information about how data was pre-processed and the huge class imbalance. Therefore, in our work, we have opted to collect the dataset on our own to obtain the most valuable information about the problem and help us to build more accurate classifiers. To help understand the problem of absenteeism in medical appointments, we analyse the reasons that leverage the decision of a patient not to attend their medical consultation. Starting from the initial dataset, we identify the main factors related to the patient's absence and propose a no-show classification model based on ML techniques. To compose the solution, algorithms that apply supervised ML techniques are used. As such, the present work brings to the current state-of-the-art a new contribution to elucidate the reasons for the no-show of healthcare patients. The main contribution of the proposed solution is to build a predictive model that can serve as a baseline model for public health centres linked to the Brazilian universal healthcare system (SUS). Furthermore, this work demonstrated how machine learning techniques have real value in predicting a patients' no-show and can help the public health sector in Brazil reduce costs and improve patient care and well-being. For that purpose, a new ML model is proposed and validated with real-life medical data, an essential tool for managing healthcare units. The remainder of this paper is organized as follows. Section 1 presents an approach to the context of the research. Section 4 describes the methodology applied in this study, including data analysis and the algorithms. Next, Section 5 discusses the results. Finally, Section 6 presents the final remarks.
# Optoelectronic Devices Based on Atomically Thin Transition Metal Dichalcogenides
## 7 Valleytronics  
Electron spin is probably the most studied quantum degree of freedom in condensed matter physics. Excitonic transitions in TMDs are not only associated with the spin degree of freedom but also with the valley degree of freedom [110]. Valley degree of freedom is a result of degenerate energy extrema in momentum space, as the \(K\) and \(K^{\prime}\) valleys in 2D materials are related to each other by time reversal. To uncover and manipulate the valley degree of freedom, all-optical methods were exploited by several groups, and it was found that the valley polarization is robust and preserved during hot-carrier relaxation, exciton formation and radiative recombination processes [27; 28; 111; 112; 113]. On the other hand, only a few studies on electro-optical valley-dependent devices have been published.  
Charge carriers in the \(K\) and \(K^{\prime}\) valleys experience effective magnetic fields with opposite signs, which allow for the generation of valley-polarization by circularly polarized optical pumping, due to the broken inversion symmetry in TMD monolayers [110]. Therefore, carriers in the according valleys experience opposite Lorentz-like forces and are deflected in opposite directions perpendicular to the current flow. In analogy to the spin Hall effect, this phenomenon is called the valley Hall effect. [PERSON] _et al._[114] measured the photovoltage, which was produced by circularly polarized light in a MoS\({}_{2}\) Hall bar device (Figure 9a). The sign of the Hall voltage could be controlled by the helicity of the light, whereas there was no effect detectable for linearly polarized light or (inversion-symmetric) bilayer devices. Other studies demonstrated a valley dependent photodetector in CVD grown MoS\({}_{2}\)[115] and the generation of spin-valley-coupled circular photogalvanic currents in WSe\({}_{2}\)[116].  
[PERSON] _et al._[65] fabricated a chiral light-emitting transistor by forming a multi-layer WSe\({}_{2}\) p-n junction using electric double layer gating. As a result of the high carrier density induced by ionic liquid gating, they were able to populate the direct gap \(K\) and \(K^{\prime}\) valleys and achieve light emission. The strong gate field breaks the inversion symmetry in the multi-layer TMD and recovers the valley circular dichroism that is otherwise only present in monolayers. The electroluminescence from their device was found to be circularly polarized, with the direction of the polarization depending on the direction of the current flow. If the device was operated in ambipolar mode and current was driven from right to left, the left-handed circular polarized light emission (\(\sigma^{-}\)) dominated over the right-handed emission (\(\sigma^{+}\)) as shown in the left panel in Figure 9b. On the other hand, by changing the direction of the current, the \(\sigma^{+}\) polarization dominated over \(\sigma^{-}\) polarization (right panel in Figure 9b). The degree of circular polarization reached values up to 45%, which is comparable to PL from TMD monolayers.
## 6 Discussion
### Disparate Impacts of Meteorological Information  
In this study, we quantified the traffic volume prediction with meteorological information. We expected that when we add the meteorological information, the models, especially the GCN, would perform better. Contrary to our expectations, the study showed that the models integrating meteorological data yielded results similar to those that did not integrate the meteorological data. These results imply that the influence of meteorological information spanning four years on traffic volume prediction is not as significant as expected compared to other external factors affecting the model. On the other hand, the counterfactual scenarios imply that when rainfall increases, traffic volume insignificantly drops. It implies a negative associations between rainfall and traffic volume. This observation can be supported by a previous study [23].
# Enhancing Cybersecurity Through Comprehensive Investigation of Data Flow-Based Attack Scenarios
## 3 Proposed Approach
### Methodology
#### 3.2.2 Attack Profile Generator  
In our proposed approach, the creation of an attack profile is a fundamental step for understanding and mitigating potential threats to a system. An attack profile encapsulates the characteristics, origins, and potential impact of each attack scenario that an adversary might employ to exploit vulnerabilities within the system. By systematically identifying these possible threats, we can prepare valuable inputs for the next steps. This section outlines our methodology for generating the attack profile.
## 5 Conclusions  
On the basis of the research, it can be concluded that the non-standard push-pull topology may be successfully implemented in the power supply to conduct GADs. In addition, it should be said that the use of parasitic parameters in the form of leakage inductance allows an effective generation of ignition overvoltages. This, in turn, allows a 60% increase in voltage for GAD ignition.  
It is also necessary to indicate some restrictions related to the selected topology of the power supply. If commutation overvoltages are used to improve ignition, use IGBTs with high maximum collector-emitter voltage. In this case, U\({}_{\text{CE}}\) = 1.2 kV keys were used. This is a high voltage, especially when compared to the full bridge topology, where it could be almost twice lower.  
Figure 6: Electrical waveforms in the \(\upmu\)GAD reactor observed during a random plasma cycle under air conditions, voltage (**a**), and current (**b**).  
The main pulse frequency band should be defined before the design stage. For the power supply described, it would not be possible to lower the frequency to 9 kHz, in the full pulse-width modulation (PWM) control range, because the core material and the winding do not allow it. The system has similar limitations at frequencies above 26 kHz. Changing the primary winding requires precise tuning of RC surge bands so that they only eliminate overvoltages that are dangerous to IGBT keys and at the same time allow the formation of ignition overvoltages. The use of microprocessor controllers, sensitive to radiated interference and conducted from the micro-gliding arc plasma reactor, also causes many difficulties [10]. These difficulties determined the use in the prototype of the power supply driver based on the analog, integrated PWM pulse width modulator.  
The experience described in the article shows that appropriate modifications of push-pull topology, known for years, allow for the implementation of this atypical solution. Moreover, the main disadvantages of topology are used here as advantages. The power supply shows good characteristics and there is no need to use any additional ignition sources. This is very important especially in conditions of air as a plasma gas.  
The designed and constructed power supply has the desired utility features required from the power electronic source of the plasma reactor. It also has numerous features that are its advantage over devices in which energy is transformed using a transformer with a network frequency, such as: good control parameters, power to volume ratio of the power supply, and high susceptibility to modifications.
# Climate-Smart Agro-Hydroological Model for a Large Scale Rice Irrigation Scheme in Malaysia
## Materials and Methods
### Flow Analysis for Storage Pond  
Because of the water shortage in the scheme, particularly during the dry season period, a storage pond was built along the main canal. Its main function is to store water during the period of low water demand in the scheme and release it in the period of high demand. The pond (reservoir) has an area of 88.41 ha with a storage pool area of 65 ha and pond water storage capacity of 1.5 million m\({}^{3}\). The initial (critical) and full (maximum) storage were considered as 0.3 and 1.5 million m\({}^{3}\), respectively. In order to analyze the reservoir release patterns in the study area, the following components were assessed: the daily supply into the storage pond, the release from the storage pond, the spill, and the total storage. The inflow into the reservoir is when the amount at the reservoir intake in the main canal is higher than the required amount downstream (at ISAs III and IV) and does not exceed maximum storage. Similarly, the release from the reservoir is when the amount at the reservoir intake in the main canal is less than the required amount downstream and the amount is not more than the critical storage.  
Supply into the storage pond (Q\({}_{\rm s}\)sp):  
\[{\rm Q_{s}sp}=0,\mbox{ for the first day}\]  
For other days:  
\[{\rm Q_{s}sp}=\left\{\begin{array}{ll}{\rm Q_{mcR}-Q_{mc/ds}},&if\;{\rm QmcR }>\,{\rm Qmc/ds};\;({\rm QmcR-Qmc/ds})<({\rm Sfsp}-{\rm St})\\ 0,&otherwise\end{array}\right. \tag{16}\]  
Release from the storage pond (Q\({}_{\rm t}\)sp):  
\[{\rm Q_{s}sp}=0,\mbox{ for the first day}\]  
\[{\rm Q_{s}sp}=\left\{\begin{array}{ll}{\rm S_{t}-\,S_{i}sp},&if\;{\rm St}> \,{\rm Sigp};\;({\rm Qmc/ds}-\,{\rm QmcR})>({\rm St}-\,{\rm Sigp})\\ 0,&otherwise\end{array}\right. \tag{17}\]  
\[{\rm Q_{s}sp}=0,\mbox{ for the first day};\]For other days:  
\[\text{Q}_{\text{o}}\text{sp}=\left\{\begin{array}{ll}(\text{S}_{\text{t}}+ \text{Q}_{\text{i}}\text{sp})-\text{S}_{\text{f}}\text{sp},&\\ 0,&\text{otherwise}\end{array}\right.\;\;if\;\text{St}>\text{S}\text{isp};\;( \text{Qmc}/\text{ds}-\;\text{QmcR})>(\text{St}-\;\text{S}\text{isp}) \tag{18}\]  
where QmcR is the available discharge at reservoir point along main canal; Qmc/ds is the water demand at downstream from reservoir point along main canal; fSsp is the full storage in the storage pond; St is the reservoir storage in the previous day; and Sisp is the critical storage in the storage pond. Finally, the total storage St+1 in the reservoir at a given day is computed as:  
\[\text{S}_{\text{t+1}}=\text{S}_{\text{t}}+\text{Q}_{\text{i}}\text{sp}+\text{ ER}-\text{EPsp}-\text{Q}_{\text{r}}\text{sp}-\text{Q}_{\text{o}}\text{sp} \tag{19}\]  
EPsp is the evaporation from the storage pond expressed as:  
\[\text{EPsp}=\frac{\text{ETo}}{\text{Kp}} \tag{20}\]  
where ER is the effective rainfall into the reservoir and Kp is the pan coefficient, 0.75.
## 1 Introduction  
Supplier selection under various conditions and selection criteria has been an important issue in supply chains since procurement costs are the dominating cost factor in many sectors. Many criteria can be considered in supplier selection such as quality, price, delivery performance, and distance to the buyer. In this study, we consider a case in which the buyer needs to optimally choose a set of suppliers and order quantities from these selected suppliers to fulfill the demand for multiple items in multiple time periods. This case is common when suppliers sell standard components with identical features and compete solely on pricing policies and closeness to potential buyers. In this problem, buyers have to make three basic decisions: (1) selection of suppliers to satisfy demand; (2) order lot sizes from each supplier; (3) routes to collect orders by multiple vehicles. In making these decisions, buyers will consider price discounts, transportation, and inventory holding costs.  
We develop a mixed-integer programming model to select the best set of suppliers and to determine the proper allocation of order quantities while minimizing the total cost which consists of the ordering, inventory holding, transportation (routing), and purchasing costs under suppliers' capacity and price discount constraints. The purpose of this study is to construct a supplier selection and lot-sizing model with price discounts in a multi-supplier, multi-component, multi-period, and multi-vehicle environment in order to minimize total cost over a planning horizon. The model permits price discounts offered by different suppliers for different components. Multiple sourcing and multiple components are considered in the model to represent a more general situation.  
The paper is organized as follows. In Section 2, literature on supplier selection, order allocation problems, and traveling purchaser problems are briefly reviewed. In Section 3, problem formulation and a mathematical model are described in detail. Section 4 is devoted to a numerical example and its solution. In Section 5, scenario analysis is provided to analyze the effects of the basic cost factors of the model on the optimal solution. Finally, the findings and conclusions of this study are presented in Section 6.
## 1 Introduction
While the aforementioned studies on AID tags provide efficient and low-cost solutions, their limited information density and the size constraints of dual-sphere configurations (e.g., radius 0.05 m, spacing 0.25 m) [14] may render them unsuitable for AUVs. Furthermore, the multilayer shell design proposed by [PERSON] et al. [15] necessitates precise control over layer thicknesses and material properties (e.g., impedance matching between acrylic and water). Nonuniform interlayer water gaps could lead to encoding distortions. Current studies reveal that dual-sphere configurations suffer from low information density, while multilayer shells exhibit encoding distortion due to nonuniform water gaps, highlighting critical limitations in existing acoustic tagging systems. This paper proposes an AID tag design method for multilayer elastic cylindrical shell structures, integrable onto AUV hull surfaces, based on the Normal Mode Series (NMS) [21]. By developing an analytical model for acoustic scattering in multilayer shells and validating it via finite element method (FEM) simulations, we quantitatively analyze the impact of material stratification strategies on far-field Target Strength (TS). Additionally, a coding generation and recognition methodology is introduced, leveraging the specificity of time-domain echo characteristics. The contributions of this paper can be summarized as follows:First theoretical framework linking layered cylindrical shell geometry to acoustic coding mechanisms. 2 Development of a hybrid NMS-FEM validation framework for systematic design optimization. 3 99% detection success rate at 3 dB SNR via impedance contrast optimization. 4 Combinatorial encoding capacity scaling (210 codes for three layers, 2520 codes for five layers).