esa-sceva/satcom-chunk-collection huggingface dataset:
# Analysis and Applications of GlobeLand30: A Review
###### Abstract  
GlobeLand30, donated to the United Nations by China in September 2014, is the first wall-to-wall 30 m global land cover (GLC) data product. GlobeLand30 is widely used by scientists and users around the world. This paper provides a review of the analysis and applications of GlobeLand30 based on its data-downloading statistics and published studies. An average accuracy of 80% for full classes or one single class is achieved by third-party researchers from more than 10 countries through sample-based validation or comparison with existing data. GlobeLand30 has users from more than 120 countries on five continents, and from all five Social Benefit Areas. The significance of GlobeLand30 is demonstrated by a number of published papers dealing with land-cover status and change analysis, cause-and-consequence analysis, and the environmental parameterization of Earth system models. Accordingly, scientific data sharing in the field of geosciences and Earth observation is promoted, and fine-resolution GLC mapping and applications worldwide are stimulated. The future development of GlobeLand30, including comprehensive validation, continuous updating, and monitoring of sustainable development goals, is also discussed.  
global land cover; analysis; accuracy; status and change; cause and consequence; sustainable development goals
# A Method for Underwater Acoustic Target Recognition Based on the Delay-Doppler Joint Feature
## 4 Experiment
### Results and Analysis
#### 4.4.1 Joint Feature Recognition Experiment
of the joint feature (TF-DD) described in this research leads to an average increase in target identification accuracy of around 6-8% compared to employing a single feature alone. This gain is rather noticeable.
# An Experimental Study on Alkali Silica Reaction of Concrete Specim Using Steel Slag as Aggregate
## 3 Results and Discussion
### Evaluation Expansion Properties of Concrete with Steel Slag  
#### 3.3.1 Evaluation Change in Length Concrete Specim Due to ASR  
The relevant ASR evaluation criteria recommended the guidelines of ASTM C 1778 [31]. ASR expansion in concrete specimens using steel slag as coarse aggregate must be evaluated according to the ASTM C 1293 [24] test method. The recommended test duration using this method is more than a year, however, in this study, the experiment was stopped when the expansion exceeded the permitted limit or had converged to constant values.  
The test results of the ASR expansion of two kinds of concrete specimens, one with steel slag and the other with natural coarse aggregate, are shown in Figure 4. As shown, the expansion of concrete specimens with steel slag was significantly higher than that of concrete specimens with natural aggregate. In the concrete specimens with natural aggregate, there were no noticeable differences in expansion with the different types of binder.  
Figure 3: Results of ASR expansion test (mortar bars).  
In the concrete specimens using steel slag as coarse aggregate, the expansion rate gradually increased for a 7 days of the test period. However, after 12 days, the expansion rate slowed down considerably and proceeded at a gradual rate. In the specimens with OPC as the binder, the expansion exceeded the permitted limit of 0.04% after 7 days. Furthermore, in contrast to the test results obtained using the ASTM C 1260 standard [23], the addition of mineral admixtures did not significantly reduce expansion, which exceeded the permitted limit after 10 days. Remarkably, even blast furnace slag, with its high specific surface area, was unable to sufficiently reduce and control the expansion of concrete using steel slag aggregate. Thus, considering the ASTM C 1293 [24] test results, additional methods are required to decrease the expansion of the concrete specimens.
## 5 Conclusions  
A new wind shear extrapolation method based on theatmospheric stability was proposed in order to calculate the wind speed at the hub height and compared with the traditional PL method. Particularly, four methods for the classification of atmospheric stability were incorporated into the WSE method. Calculations were performed for flows in three different areas, namely SJB, GFC and HNH, to verify the suitability of the proposed methods. Conclusions can be drawn as follows:  
1. For SJB, the plateau where the surface is wasteland, the WSE-RG, WSE-WSR and WSE-MO methods can well calculate the wind speed at the hub height. When two-level temperature data is available, the WSE-RG and WSE-MO methods are more effective, of which MRE of WSE-MO is 0.22% (MRE of PL is \(-\)1.58%) and RMSE of WSE-RG is 0.3231 m/s (RMSE of PL is 0.3780 m/s). When there are not enough temperature data, the WSE-WSR method is most effective, of which MRE is \(-\)1.52% and RMSE is 0.3311 m/s.
2. For GFC, the mountain where the surface is shrubbery, the WSE-WDSD and WSE-WSR methods perform well and the WSE-WDSD method is most effective, of which MRE is \(-\)0.02% (MRE of PL is 0.33%) and RMSE is 0.5276 m/s (RMSE of PL is 0.5430 m/s).
3. For HNH, the plain where the surface is farmland, the WSE-WDSD and WSE-WSR methods are also suitable. MREs of the WSE-WDSD and WSE-WSR methods are \(-\)3.17% and \(-\)3.26%, respectively (MRE of PL is \(-\)7.38%) and RMSEs of the WSE-WDSD and WSE-WSR methods are 0.7931 m/s and 0.7035 m/s, respectively (RMSE of PL is 0.6005 m/s). The WSE-WSR method is recommended when the atmosphere is unstable in most of the time.
4. The new WSE model proposed in the present work has advantages over the traditional PL method. Besides, the WSE-WDSD method for extrapolating the wind speed at the hub height is more effective in plain terrain. WSE-WSR is suitable in complex terrain. Besides, the WSE-RG and WSE-MO methods have more advantages when \(Ri\) and \(L\) can be calculated.  
Methodology, C.X.; Writing-Original Draft Preparation, C.H. and L.L.; Writing-Review and Editing, X.H., F.X., M.S. and W.S.  
Authors are grateful to the support by the Jiangsu Science Foundation for Youths (Grant No. BK20180505), the China Postdoctoral Science Foundation (No. 2018M630502), the Fundamental Research Funds for the Central Universities (No. 2018B01614) and the International Cooperation of Science and Technology Special Project (No. 2014 DFG62530).  
The authors declare no conflict of interest.  
List of Symbols PL Power law WSE Wind speed extrapolation method WSE-RG Wind speed extrapolation method based on the Richardson gradient method WSE-WSR Wind speed extrapolation method based on the wind speed ratio method WSE-WDSD Wind speed extrapolation method based on the wind direction standard deviation method WSE-MO Wind speed extrapolation method based on the Monin-Obukhov method MRE Mean relative error RMSE Root-mean-square error, m/s
## 4 Experiments and Results
### Evaluation
At first, XGBoost is very slow with the performance while using all the features (60.24 s), but with the reduction of the features, it sees improvement in both the speed and the memory used. In FL, its performance stabilizes and recovers to improved performance in terms of execution time and moderate memory usage. Gradient Boosting, on the other hand, is the slowest model in all the scenarios analyzed for all the models, especially all features reduced to over 400 s after reducing the features. Memory usage does improve a little, but the time taken to run this model is still far behind that of other models and more especially in the FL case. Overall, the table demonstrates that diminished feature sets lead to more accurate machine-learning models while optimizing both speed and memory consumption. Federated Learning offers a bit slower operation but on reasonable resources, so it can demonstrate its usability in distributed environments. These insights give an articulation of the precise models appropriate for DDoS detection in IoV systems, bearing in mind the constraints of available resources and the urgency of response. Figure 7: Confusion matrices for Model (**a**), Model (**b**), Model (**c**), Model (**d**), and Model (**e**): (**a**) Confusion Matrix for Decision Tree Model. (**b**) Confusion Matrix for Random Forest Model. (**c**) Confusion Matrix for XGBoost Model. (**d**) Confusion Matrix for Gradient Boosting Model. (**e**) Confusion Matrix for K-Nearest Neighbors Model. In each confusion matrix, color intensity shows prediction frequency, with darker shades indicating higher values and lighter shades showing lower values, helping to spot misclassifications. Figure 8 highlights the running time of different models, with GradientBoostingClassifier being the most time-consuming, especially when using all features. As an ensemble model, it builds trees sequentially, which limits parallelization and increases computational cost. With more trees and a larger dataset, the training time grows significantly. In contrast, Decision Tree and KNN are more efficient. Reducing the feature set to 25 notably lowers the running time for all models, while federated learning models show similar performance to reduced-feature traditional models with minimal overhead. Figure 9 illustrates the memory usage of the same models under similar scenarios. Models utilizing all features exhibit the highest memory consumption, whereas reducing the features to 25 significantly lowers the memory usage. Federated learning models also demonstrate reduced memory requirements compared to models trained on all features, with only a slight increase compared to traditional machine learning models with 25 features.
###### Abstract  
The continuous growth of interconnected devices in the Internet of Things (IoT) presents a challenge in terms of network resources. Cognitive radio (CR) is a promising technology that can address the IoT spectral demands by enabling an opportunistic spectrum access (OSA) scheme. The application of full duplex (FD) radios in spectrum sensing enables secondary users (SUs) to perform sensing and transmission simultaneously, and improves the utilization of the spectrum. However, random and dense distributions of FD-enabled SU transmitters (FD-SU TXs) with sensing capabilities in small-cell CR-IoT environments poses new challenges, and creates heterogeneous environments with different spectral opportunities. In this paper, we propose a spatial and temporal spectral-hole sensing framework for FD-SU TXs deployed in CR-IoT spectrum-heterogeneous environment. Incorporating the proposed sensing model, we present the analytical formulation and an evaluation of a utilization of spectrum (UoS) scheme for FD-SU TXs present at different spatial positions. The numerical results are evaluated under different network and sensing parameters to examine the sensitivities of different parameters. It is demonstrated that self-interference, primary user activity level, and the sensing outcomes in spatial and temporal domains have a significant influence on the utilization performance of spectrum.  
c 2019 19 1441 19 March 2019 23 March 2019
## 2 Wear Prediction Model of DPRSs Considering Ambient Temperature
### Rough Surface Contact Analysis of DPRSs
#### 2.1.1 Characterization of Rough Surfaces  
To study the temperature rise, thermal deformation, and wear of DPRSs, the Majumdar-Bhushan (M-B) fractal function is used to characterize the two-dimensional profile of the rough surface of the DPRS:  
\[z(x)=G^{F-1}(2r)^{2-F}\cos(\frac{\pi x}{2r}),(-r<x<r), \tag{1}\]  
where \(r\) is the contact radius, \(F\) is the two-dimensional fractal dimension (\(1<F<2\)), and its relationship to roughness \(R\) can be obtained from the following empirical formula:  
\[F=\frac{1.528}{R^{0.042}}. \tag{2}\]  
\(G\) is fractal roughness, and its approximate exponential relationship to roughness \(R\) is as follows:  
\[G=10^{-(5.26/R^{0.042})}. \tag{3}\]
## 1 Introduction
* The integration of glycerin-made resonators into patch antennas yields distinct effects on the scattering parameter \(S_{11}\) and radiation patterns, depending on the geometry shape. Some geometries show potential for reducing the size of patch antennas because they downshift the resonant frequency, while others enhance radiation efficiency or improve the scattering parameter \(S_{11}\). Other geometries provide a balance between enhanced scattering parameter \(S_{11}\) and radiation patterns. These variations in the results demonstrate the versatility of glycerin resonators in improving patch antenna performance, particularly for size reduction and improved efficiency. * The combination of graphite-made resonators with patch antennas results in significant changes in scattering parameters \(S_{11}\) and the radiation pattern. These resonators typically cause shifts in resonant frequency, with certain configurations exhibiting more pronounced shifts. The radiation pattern is also improved, with specific geometries offering high effective gain and enhanced directionality compared to a patch antenna without a resonator. Overall, graphite resonators present substantial potential for improving patch antenna performance concerning BW, radiation efficiency, and radiation directionality, making patch antennas more compact and efficient for a broader range of applications. The remainder of the paper is organized as follows. Section 2 formulates the investigated problem. Section 3 describes the materials and geometries used in the resonators. Section 4 analyzes the numerical results. Lastly, Section 5 presents the concluding remarks.
## 2 Theory and Calculation Model
### PIC Simulation Model
The particles that hit the wall are removed but their charge will be accumulated on the wall surface [19], and the wall potential can be calculated using the IFE method based on the charge density on the wall. [PERSON]'s equation is not solved in the _Oz_ direction. When particles run out of the boundary along the _Oz_ direction, they will be re-injected from the opposite side while keeping the position and velocity in the (_Ox-Oy_) plane unchanged. However, to prevent particles from being infinitely accelerated along the _Oz_ direction, the velocities of the re-injected electrons need to be redistributed with the initial temperature \(T_{e}\), and the ion velocities need to be reset as 0 because they are considered to be cold. In order to maintain stability and reduce numerical heating, the PIC simulations require a time step that satisfies [20]:  
\[\Delta t<\frac{0.2}{\omega_{pe}} \tag{3}\]  
where \(\omega_{pe}=\sqrt{(e^{2}n_{e})/(\varepsilon_{0}m)}\) is the electron plasma frequency. At the same time, the grid spacing also needs to be limited as follows [20]:  
\[\Delta x<\lambda_{De} \tag{4}\]  
where \(\lambda_{De}=\sqrt{(\varepsilon_{0}T_{e})/(|e|n_{e})}\) is the Debye length with \(T_{e}\) the electron temperature. In order to reduce numerical heating and statistical noise, PIC simulations usually require approximately 100 particles per cell. The parameters involved in this paper are given in Table 1. The reliability and accuracy of the model used in this paper have been verified in Ref. [21].
# Color Brightness Recognition of Extremely Severe Amblyopia Children in an Indoor Environment
###### Abstract  
This study aims to investigate how indoor lighting (natural and artificial) and distances (3 m and 5 m) affect color recognition in visually impaired children. Ten participants from a special education school were selected to identify the brightness of five colors at varying lighting and distance circumstances. Each color was presented at six different brightness levels, classified into the low-brightness, the standard-color, and the high-brightness groups. Participants were directed to assess the top three brightness levels they considered most attractive, and each rating was assigned a weighted score. The findings revealed that: (1) Visually impaired children can recognize color brightness in both natural and artificial lighting situations. In indoor conditions, the low-brightness group exhibited greater recognition ability compared to the high-brightness group. Purple did not exhibit a clear pattern, as colors from the high-brightness, the low-brightness, and the standard-color groups were all preferred. (2) Significant differences were observed in the brightness recognition among visually impaired children at distances of 3 m and 5 m. Recognition for low-brightness colors improved with distance, contrasting high-brightness scores that declined. However, there was no significant variation in the perception of green with distance changes.  
Keywords:visually impaired children; special education schools; color brightness; lighting distance +
Footnote †: journal: Applied Sciences
# Retrospective Study on Seismic Ionospheric Anomalies Based on Five-Year Observations from CSES
## 2 Data Introduction and Processing Methods  
CSES-01 mainly aims to obtain dynamic information on the geomagnetic field and ionospheric environment to support applications in the fields of geophysical exploration, EQ prediction science, as well as the global geomagnetic field and ionosphere modeling, etc. [20]. A large number of EQ case studies based on CSES-01 observations help understand the EQ preparation and occurrence processes and provide support for exploring the mechanisms of the LAIC [24]. The CSES satellite adopts a three-axis stable sun-synchronous orbit with an altitude of 507 km. The local times of the ascending and descending nodes are 02:00 a.m. (nightside) and 2:00 p.m. (dayside), respectively, and the revisiting period is 5 days. The special altitude and local times provide specific and long-term stable observations for exploring ionospheric characteristics, seismic ionospheric anomalies, and their mechanisms [15].
## 2 Materials and Methods
### Cell Cytotoxicity and Proliferation Assay  
For the evaluation of the effects of the LLP on cell metabolic activity and proliferation, the MTT assay and bromo-deoxyuridine (BrdU) incorporation assays were performed. The MTT test is a colorimetric assay based on the ability of mitochondrial oxidoreductase enzymes to convert MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolzolium bromide), a soluble, colorless reagent, into purple formazan crystals, whose formation can be quantified by spectrophotometric techniques. The production of insoluble salts derived from MTT is proportional to mitochondrial metabolic activity. The MTT assay is widely used to study cell viability, proliferation, and cytotoxicity. However, since the treatment can alter cell metabolic activity without altering cell replication, the MTT assay was associated with bromo-deoxyuridine (BrdU) incorporation assay, a more specific test for the quantification of cell replication. A direct cell count was also performed to evaluate cell replication in the presence of LLP.
# An Efficient Routing Scheme Based on Node Attributes for Opportunistic Networks in Oceans
## 2 Related Works
### Copy-Based Routing  
The copy-based routing strategy generates a certain number of message copies in opportunistic networks to improve the success delivery ratio of the destination. Direct transmission [10] utilizes the single-copy strategy to deliver directly the packets from source to its destination, not relying on any additional intermediate nodes. In this algorithm, all packets are delivered only once, and thus have minimal network overhead. However, it has a higher delay and great risks of packet loss. Epidemic routing [11] produces several copies of the information among all the neighbors in each hop, and copies action continues until the information delivers to the destination, and the process is successfully delivered with lower latency. However, too many copies can cause broadcast traffic, which in turn significantly degrades network performance. Compared to Epidemic routing, SprayandWait routing [12] distributes a few message copies into the network, and then routes each copy independently toward the destination, which performs significantly fewer transmissions and lower average delivery delays.
## 3 DCPSO with Cooperation  
As addressed above, cooperative path-planning for multi-UAV formation rendezvous is mostly a complicated multi-objective optimization problem with many coupled constraints. The solutions of the problem are a collection of UAV paths and each UAV path is part of the solution set. The relationship between these two is similar to that between population and subpopulation in the co-evolutionary theory [32]. Inspired by the co-evolutionary theory, cooperative co-evolutionary genetic algorithms (CCGA) have been applied in path-planning for multiple robots or UAVs [33; 34]. However, the conventional CCGA has low search efficiency and may easily trap local optimum. The existing cooperative particle swarm optimization (CPSO) [35; 36] can easily jump out of local optimum, but they lack effective cooperation between subpopulations and cannot be directly used for path-planning for multiple UAVs. To take full advantage of CPSO, a distributed cooperative particle swarm optimization (DCPSO) algorithm with cooperation is proposed.
## 1 Introduction
### Benchmark Against State-of-the-Art Techniques  
On reversible spectral speech watermarking, there are essential benchmarks against state-of-the-art techniques in terms of perceptual quality, robustness, and anti-steganalysis capabilities.  
1. **Perceptual quality**: We specified variable embedding locations to embed the watermark to maintain high perceptual quality. Using adaptive embedding strategies, distortion is kept imperceptible to human listeners. Furthermore, the proposed adaptive hiding method enhances the traditional spread spectrum technique to ensure that the watermark remains inaudible while maintaining the integrity of the speech signal.
2. **Robustness**: This refers to the system's ability to maintain the integrity and retrievability of embedded watermarks under various signal processing or attack scenarios while ensuring that the original speech signal can be perfectly reconstructed. Typically, watermarking methods are designed to be robust against various signal processing attacks, such as compression, filtering, and time-frequency manipulations. This robustness is crucial for ensuring the watermark's integrity even after the signal undergoes these common transformations. However, the proposed method in this context focuses solely on tampering detection, not watermarking. Therefore, robustness against these attacks is not a primary concern. The rationale is that any data loss or bit error within a specific frame will be immediately flagged as a potential tampering event, and that frame will be subsequently discarded.
3. **Anti-steganalysis**: This focuses on resisting steganalytic attacks by concealing the watermark's presence within the speech signal. These methods often involve complex algorithms to ensure that the watermark is not easily detectable. MP3 stego, CNN-based steganalysis, and time-domain and spectral-domain steganalysis approaches are popular in audio steganalysis. Table 1 lists the survey of audio steganalysis methods. Since the proposed method is based on spectrum expansion, being different from work [29] to calculate the features in DeepResNet, the proposed method calculates the likelihood of the spectrum coefficients to achieve a fast and lightweight approach to detect watermarks.