esa-sceva/satcom-chunk-collection huggingface dataset:
# Impact Testing of 3D Re-Entrant Honeycomb Polyamide Structure Using Split Hopkinson Pressure Bar
###### Abstract  
In this study, a total of 30 3D re-entrant honeycomb specimens made of polyamide were fabricated with various configurations by using the additive manufacturing (AM) technique. Split Hopkinson Pressure Bar (SHPB) tests were conducted on the RH specimens at different impact velocities. The incident, reflected and transmitted waveforms can well explain the wave propagation and energy absorption characteristics of the specimens, which can help us to understand and analyse the process of impact loading. The stress-strain curves, energy absorption ability and failure modes of SHPB tests with different impact velocities and quasi-static compression tests were analysed and compared, and it was found that the flow stress and energy absorption ability of the specimens subjected to impact load were much improved. Among the tested specimens, specimen C2, with a smaller re-entrant angle \(\theta\), displayed the best energy absorption ability, which was 1.701 J/cm\({}^{3}\) at the impact velocity of 22 m/s and was 5.1 times that in the quasi-static test. Specim C5 had the longest horizontal length of the diagonal bar \(L_{0}\), and its energy absorption was 1.222 J/cm\({}^{3}\) at the impact velocity of 22 m/s and was 15.7 times that in the quasi-static test, reflecting the superiority of a structurally stable specimen in energy absorption under impact loading. The test results can provide a reference for the optimization of the design of the same or similar structures.  
SHPB impact test; 3D re-entrant honeycomb; additive manufacturing; dynamic response; energy absorption +
Footnote †: journal: Applied Sciences
# Flexible Convolver for Convolutional Neural Networks Deployment onto Hardware-Oriented Applications
## 1 Introduction
This paper describes the architecture of a systolic array-based general-purpose hardware convolver, whose main feature is the capability of adapting to any convolution hyperparameter. Unlike the state-of-the-art works, where the standard algorithm for convolution is modified to improve the performance, the proposed convolver can receive raw feature maps and weights to deliver an output whose precision is only limited by the number of bits in data representation. The convolution operation with systolic arrays is usually conducted as a matrices multiplication in related works [42], which requires a previous processing stage, and irregular data memory access [10]. Tiles-based data processing is often used too, but a data processing stage after the convolution computing is implied to compensate for the quantization error due to not being able to apply the filters on the edges of the tiles [37]. The proposed architecture design belongs to the second design strategy (SCE), which allows it to be used in classification, object recognition, or segmentation applications in digital images processing without any additional adaptation. Mobile on-chip data processing, not requiring cloud computing, avoiding internet potential security risks, is one of the potential applications [43]. The deployment of CNN with any configuration targeting limited-resources hardware is possible thanks to this new design strategy. The work described in this paper has the following differences from other reported ones:  
* State-of-the-art works typically modify the convolution algorithm, which involves tuning the hardware to a single CNN configuration. The proposed method allows processing any convolution layer configuration without customizing the standard algorithm. Hence, the convolver architecture can be adapted to different CNN structures. * The present work proposes an adaptive line buffer, where the convolution masks are dynamically generated; that is, the proposed buffer is programmable where the mask size can be defined through the external control. The need to reconfigure the design for each new CNN is avoided. * The proposed architecture flexibility is demonstrated by its implementation in different CNN layers. From the results, a potential competitive total processing time is achieved compared with recently reported architectures. The paper organization is as follows. Section 2 is divided into three parts: First, a brief description of CNN definitions is presented. Second, a general explanation of the proposed architecture is presented. Lastly, the detailed description of the proposed systolic architecture is depicted. The experimental results and discussion are presented in Sections 3 and 4, respectively.
# Backscatter Communications: Inception of the Battery-Free Era--A Comprehensive Survey
## 10 Conclusions  
In this survey, we presented BackCom as a solution to address energy problems in emerging wireless heterogeneous networks. First, we explored the limited battery life problem from a cellular perspective, in a disaster management scenario, and in the IoT context, since limited battery life is the primary cause of power interruption in wireless communications. Next, we suggested BackCom as a solution to the energy problem and elaborated the basics of signal backscattering, the evolution of BackCom, and BackCom tag's architecture in addition to various types of BackCom. We explained various signal processing aspects in BackCom such as channel coding, interference, decoding, and signal detection schemes including coherent and non-coherent detection techniques. Moreover, we discussed BackCom communication modes involving half-duplex and full-duplex modes followed by modulation techniques and multiple access schemes. Subsequently, we highlighted different power sources for BackCom in addition to efficient energy and data transfer approaches, while considering scheduling and resource allocations schemes for uninterrupted communications. The BackCom coverage problem was then explored with different solutions for range extension. Afterward, we illustrated security measures and reliability techniques for BackCom followed by BackCom applications. Finally, we concluded with current challenges and future directions for BackCom to address the high-technology needs of battery-free communication in next-generation 5G wireless communications.  
Figure 50: Future directions.  
**Acknowledgments:** This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2016R1D1A1B03935633).  
**Conflicts of Interest:** The authors declare no conflict of interest.
## 1 Introduction
Moreover for efficient cloud access, this study implemented a scheduling approach through workflow optimization. Workflows are commonly used to model data flow and commands for each application deployed in the cloud. The workflow consists of tasks and data control between tasks. Ordinary workflows are described by a directed acyclic graph (DAC) that consists of tasks and controls, represented by nodes and edges, respectively. Users pay for cloud services based on executed workflows, where workflow execution must be in accordance with any time limits and quality of service agreed upon between users and cloud service providers. On the other hand, cloud service providers try to minimize the cost and execution time of workflows to obtain greater profits. Here, a scheduling algorithm which requires minimizing costs but not reducing the level of satisfaction of cloud user services was the main challenge [8]. Cloud computing can provide the opportunity to continue to take advantage of new developments in IT technologies at affordable costs [9]. Moreover, cloud intelligent system use for digital ecosystem general purpose activity, learning, school-from-home, work-from-home, and making a start-up business in relation to the pandemic situation is increasing. There are many uses of cloud intelligent system which have been addressed in this study. Digital ecosystems connect people across the globe where they are able to stay in contact and share their experiences. The various cloud intelligent system platforms have different features that are available for use by their subscribers. Cloud intelligent systems have also made easier for people to do business, due to the fact they open up the global market and make it cheaper to advertise. This paper is structured as follows: Firstly, in the literature review section the details for each of the terms used and the benefits of cloud intelligent systems, especially during the pandemic, are illustrated. Secondly, the methods used in the proposed the cloud apps intelligent system scheduling methods, gathering the data and what are the limitations are discussed. Thirdly, the key differences and similarities between the uses of the terms are shown and discussed with support from findings in the literature that is related to research in the cloud intelligent system area. In addition, the different views of the use of cloud intelligent systems are introduced using real-life examples since it is the foundation for understanding these terms. Finally, the results of the different views are discussed in the conclusions part where some recommendations are also given.
## 5 Discussion
### Comparison with Related Works  
In the dynamic field of network security, particularly concerning WLANs and their resilience against APTs, our study stands out for its comprehensive and multifaceted approach. This section contrasts our research with other recent works in the field, highlighting the unique aspects and depth of our analysis.  
Our research distinguishes itself by adopting a holistic approach, a criterion noticeably absent in all the discussed works [4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14]. This comprehensive perspective is crucial for understanding the multifaceted nature of WLAN security in the context of APTs. Unlike these studies, we do not isolate individual aspects of WLAN security but consider the entire ecosystem, providing a more thorough understanding of the vulnerabilities and resilience strategies.  
Another critical area where our research excels is in considering attack scaling. Studies like [6; 9; 12; 13] touch upon this aspect, but they do not explore it to the extent we have. Understanding how APTs scale their attacks is vital for developing robust defense mechanisms, a gap our research aims to fill.  
In the realm of ISP-side traffic analysis, our study is the first among the compared works to delve into this area. This analysis is crucial for identifying and mitigating APTs, as it offers insights into traffic patterns that could indicate a breach or an ongoing attack.  
Considering the resources of APTs is another area where our study stands out. All of the studies in the comparison do not take into account the significant resources at the disposal of APTs. Our research fills this gap by analyzing how the resourcefulness of APTs affects the efficacy of current WLAN security measures.  
Finally, the consideration of compromised insider nodes sets our study apart. While most studies like [5; 6; 8; 9; 10; 11; 12; 13; 14] acknowledge this aspect, they do not explore it in depth. Our research not only recognizes the role of insider threats in WLAN security but also provides insights into mitigating such risks.  
Table 11 vividly illustrates our research's comprehensive and unique approach in the field of WLAN security against APTs.
# Flow-Induced Vibration Analysis by Simulating a High-Speed Train Pantograph
## 6 Conclusions  
This article presents a novel method for establishing a full-flexible high-speed pantograph flow-induced vibration model using external aerodynamic loads and modal simulation data of the pantograph as inputs, combined with the modal superposition method. This method was utilized to analyze the dynamic response of high-speed pantographs under different speeds and knuckle-downstream and knuckle-upstream operating conditions. The following findings were obtained: Compared to before entering the tunnel (approximately 2 s prior), the displacement and contact force of the pantograph significantly increase after entering the tunnel. As the operating speed increases, the displacement and contact force of the pantograph also significantly increase. Compared to the knuckle-upstream operating condition, when running in the knuckle-downstream operating condition, the pantograph experiences upward aerodynamic forces, leading to an increase in the displacement of the pantograph and the maximum contact force, average contact force, and contact force standard deviation of the contact wire. This results in an increase in the offline rate, thereby affecting the stability of the current collection.  
Analysis of flow-induced vibration of high-speed pantograph structures under the condition of 400 km/h operating speed reveals significant vibration reduction potential in the stiffness of the pneumatic cushion equivalent spring and the density of the pantograph head. Effective reduction of the contact force between the pantograph and the contact wire during high-speed operation can be achieved by adjusting the stiffness of the pneumatic cushion equivalent spring and the density of the pantograph head. These findings provide support for the design optimization of new pantograph structures.  
Conceptualization, X.L.; methodology, D.W. and X.L.; software, C.S.; formal analysis, D.W., Z.W. and C.S.; writing--original draft preparation, D.W., R.L. and C.S.; writing review and editing, D.W., Z.W., C.S. and X.L.; supervision, X.L.; funding acquisition, X.L. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Shandong Province Major Science and Technology Innovation Project Funding (grant number: 2021 ZDPT02). Fundamental Research Funds for the Central Universities of Central South University, grant number 1053320232705.  
Not applicable.  
Data Availability Statement: Data is contained within the article.  
Figure 31: Response diagram of pantograph head density/stiffness to pantograph mesh contact force.  
Conflicts of Interest: Author [PERSON] was employed by the company CRRC Academy (Qingdao) Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
# Toward Integrated Satellite Operations and Network Management: A Review and Novel Framework
## 3 Integrated Management Framework
### Plan Executor Module Technical Implementation
#### 3.1.2 Telemetry Integration and Feedback Loop  
The module implements a telemetry feedback mechanism that continuously monitors satellite resource levels (memory, energy) and task completion status. When deviations from predicted states are detected, the Plan Executor automatically triggers rescheduling to accommodate these changes. This closed-loop approach enables the system to react to scenario uncertainties and maintain optimal performance despite dynamic conditions.  
Figure 2: Sequence diagram of the Plan Executor’s dynamic execution.  
The module maintains databases for schedule history, resource predictions, and telemetry data to support this adaptive capability.
## 3 Results and Discussion
### Partial Least Square Discrimination Analysis of Volatile Compounds  
Multivariate analysis has been used successfully to distinguish varieties of apricot [40]. In the present study, partial least square discrimination analysis (PLS-DA) was applied to graphically classify sample groups based on similarity and/or dissimilarity of volatile compounds in the four apricot cultivars [41]. As indicated in Figure 3, the total cumulative variance of 59.6% was contributed to by the two principal components (PC1 and PC2) from volatile compounds, and they accounted for 35.0% and 24.6% of the total variance, respectively. Furthermore, it was obvious that the four apricot varieties were well separated. The result suggested that there were clear differences among the four different apricot cultivars. The loading graph (Figure S2) provided the distribution of volatile compounds of four apricots. XB apricot was characterized by 1-octanol, nonanol, salicaldehyde and eucalypt. There was a positive correlation between XB apricots and these four volatiles. Furthermore, the DBY apricot was separated from the other three apricot varieties along PC2 (Figure 3). The characteristics of the PLS-DA model strongly corresponded to the above results for compounds. In conclusion, the obvious difference in volatile compounds among the different apricot varieties provided a great basis for identifying the biomarkers for the four apricot cultivars.  
Figure 3: Partial least square discrimination analysis (PLS-DA) of volatile compounds in four different apricot cultivars. DBY, Dabaiyou apricot; LPH, Luopuhongdaike apricot; YOU, You apricot; XB, Xiaobai apricot.
# Wireless Strain Gauge for Monitoring Bituminous Pavements
## 6 Conclusions  
This article introduced the method and feasibility of a deformation measurement device implemented in a core of materials identical to the pavement and re-established by gluing. The device can measure the longitudinal and transverse deformations in a pavement layer. The implementation of the sensor can be carried out after the construction of the asphalt concrete layer. Installation after construction work simplifies the electronic design and the problems of destruction during compaction or high temperatures. The lifespan of sensors installed in roadways is also often limited by the wires. This wireless data transmission technique will therefore increase the lifespan of instrumented structures. The supercapacitor and wireless charger allow the device to be implemented entirely inside the core and remain perfectly autonomous. The electronic part of the wireless sensor is nevertheless more difficult to design than simple wired sensors. Energy storage can, however, increase the size of the circuit and the transceiver can sometimes make noise in the measured signal.  
The measurement results were validated using measurements on a conventional gauge system as well as using the results from a reliable numerical model. These main innovations open the way to building long-life real-time pavement monitoring systems. With this system, a sampling frequency of \(1\) kHz can be achieved, which allows us to capture the dynamic behavior of the pavement (as can be found with higher vehicle speed or a traffic simulator and the falling weight deflectometer test). This high frequency can provide more detailed information about the pavement response to loading, and can help identify critical points within the pavement structure. Finally, we plan for future tests on an instrumented roadway with further testing of this new sensor in different loading, position, and temperature configurations.  
Conceptualization, P.R. and C.P.; methodology, C.G.; software, D.C.d.S.; validation, B.P, N.R.-R. and C.P.; formal analysis and investigation, C.G.; data curation, C.G.; writing--original draft preparation, B.P. and C.G.; writing--review and editing, B.P. and N.F.; supervision, C.P. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy.  
The authors would like to acknowledge the company Spie Batignolles Malet (Toulouse, France) and [PERSON], for building the pavement layers used for these tests and for his support in developing the test program.  
The authors declare no conflicts of interest.
## 4 Campi Alto di Norcia: Description of the Historical City Centre
### Damage Survey and Assessment through EMS98 Procedure  
The seismic event of August and October 2016 required the deep in-situ surveys of the structural damages undergone by the buildings constituting the historical city centre of Campi Alto di Norcia. Inspections were performed in the immediate post-emergency phase, by expert technicians following the indications of the AEDES forms [28] for the detection of the partial and local collapses, cracking scenarios, structural failures, resulting deficiencies, etc. The European Macroseismic Scale (EMS)98 [29] was then adopted and applied to the different constructions with the aim of assigning a 'damage class' to each SU of Campi Alto di Norcia. The EMS98 scale provides graphical illustrations and descriptions of six different increasing damage levels--DL (i.e., D0, D1, D2, D3, D4 and D5--corresponding, respectively, to the lack of damage, negligible to slight, moderate, substantial to heavy and very heavy damage, and full destruction). With the aim of reducing the variability related to the personal expertise of the surveyor [28], three different independent judgements were used, applying then the average to the performed estimations. Table 4 and Figure 6 show the distribution of the damage level for SUs, in terms of percentage of buildings and volume of construction. Most SUs shows a DL equal to D2-D3 and D4-D5, but most of the volume turns out to be in the range D2-D3, since many SUs, used as storage areas and cellars with a low volume, are nowadays fully collapsed. Storage areas and cellars were not further considered in the assessment procedure, therefore reducing the number of analysed SUs to (only) 67.  
Figure 7 shows a comparison performed, in a GIS environment, between the DL of the SUs and the retrofit interventions carried out after the seismic events of 1979 and 1997. Most of the SUs, where the timber roofs and timber floors were replaced with concrete slabs (\"storey stiffening\" intervention marked in red), show a damage level D4-D5. The SUs
# An Improved YOLOv5 Algorithm for Drowning Detection in the Indoor Swimming Pool
## 6 Conclusions
The model's fast inference speed of 3.7 ms allows rapid screening of real-time images. The combination of high accuracy and rapid inference speed positions the model as a valuable asset for real-time drowning detection at swimming pools, ensuring timely identification of incidents and contributing significantly to drowning prevention efforts. In this paper, we present an improved YOLOv5 algorithm designed for the timely detection of drowning incidents in indoor swimming pools. 1. Two key improvements were implemented to augment the original YOLOv5 algorithm. Firstly, the ReLU activation function in the coordinated attention (CA) module was replaced with the SiLU activation function, resulting in a refined coordinated attention module (ICA). Additionally, the PAN module was substituted with the bi-directional feature pyramid network (BiFPN). 2. To evaluate the accuracy of the improved YOLOv5 algorithm, a self-made dataset was generated. Four college students simulated drowning scenarios and various water poses under drone surveillance, with relevant images extracted to form a dataset comprising 8572 images. 3. The improved YOLOv5 algorithm exhibited a noteworthy 1.3% improvement in precision compared to the original YOLOv5 algorithm. It achieved a recall rate of 98.0% and mean average precision (_mAP_) values of 98.5% and 73.3% at 0.5 to 0.9 IOU thresholds, respectively, meeting the stringent accuracy requirements for drowning detection. Consequently, the use of a self-made dataset in conjunction with the improved YOLOv5 algorithm for drowning recognition proves to be a viable approach. Moreover, the effect of accurately detecting individuals drowning on the water surface is satisfactory. And the model's capability to accurately detect individuals drowning on the water surface, with a precision of 98.1%, underscores its high value in drowning detection and rescue operations. Conceptualization, R.Y. ; methodology, R.Y. and K.W. ; software, K.W. and L.Y. ; validation, K.W. ; formal analysis, R.Y., K.W. and L.Y. ; investigation, R.Y. and L.Y. ; resources, K.W. and L.Y. ; data curation, K.W. ; writing--original draft preparation, K.W. ; writing--review and editing, K.W. and L.Y. ; visualization, K.W. ; supervision, R.Y. ; project administration, R.Y. ; funding acquisition, R.Y. and L.Y. All authors have read and agreed to the published version of the manuscript. This research received no external funding.