esa-sceva/satcom-chunk-collection huggingface dataset:
# Solar Sail-Based Mars-Synchronous Displaced Orbits for Remote Sensing Applications
###### Abstract  
A solar sail is a propellantless propulsion system that allows a spacecraft to use solar radiation pressure as a propulsive source for planetary and deep space missions that would be difficult, or even unfeasible, to accomplish with more conventional thrusters, either chemical or electric. A challenging application for these fascinating propulsion systems is a heliocentric mission that requires a displaced non-Keplerian orbit (DNKO), that is, a solar sail-induced closed trajectory in which the orbital plane does not contain the Sun's center of mass. In fact, thanks to the pioneering work of [PERSON], it is known that a solar sail is able to reach and maintain a family of heliocentric DNKOs of given characteristics. The aim of this paper is to analyze the properties of Mars-synchronous circular DNKOs, which have an orbital period matching that of the planet for remote sensing applications. In fact, those specific displaced orbits allow a scientific probe to continuously observe the high-latitude regions of Mars from a quasi-stationary position relative to the planet. In this context, this paper also analyzes the optimal (i.e., the minimum-time) heliocentric transfer trajectory from the Earth to circular DNKOs in two special mission scenarios taken as a reference.  
solar sail; displaced non-Keplerian orbit; Mars exploration; optimal transfer trajectory; preliminary mission design +
Footnote †: journal: Applied Physics Letters
## 8 Conclusions  
The validity of the determination of the rock mass deformation modulus using the plate load tests conducted at the Bazoft dam project site was evaluated numerically. The 3D numerical simulation, using the Mohr-Coulomb constitutive model, was successfully used to simulate the in-situ PLT conducted at the Bazoft dam. The analysis showed that the optimum measurement depth for rock mass modulus calculation is approximately  
Figure 17: A Comparison of modulus values determined for Bazoft dam right abutment employing different methods.  
equal to the loading plate radius. The data determined from measurement depths beyond one plate diameter can be erroneously high and unrealistic. In practical applications of the plate load test, the diameter of the loading platen is reduced from the standard size to smaller values to ease the test. This affects the stress field provided by the loading plate and significantly influences the test data and leads to erroneous results in the calculation of rock mass modulus. The analysis results show that the plate diameter can have a significant effect on test results. As the measurement depth increases, the determined modulus values increase at a much more rapid pace when employing smaller loading plates as illustrated in Figure 17. By measuring plastic strains in each loading/unloading cycle, it was shown that by an increase in plate diameter, the amount of plastic strain, for a given measuring point, would increase leading to the reduction of the rock mass stiffness and consequently deformation modulus. Based on obtained results, it is concluded that the initial vertical parts of the load-displacement curves or consequently stress-strain curves (vertical slope) are due to a time lag between loading and unloading phases and also the distance between loading plates and measurement points. Therefore, the vertical parts should not be taken into account in the determination of rock mass modulus. Considering the fundamental shortcomings of the ISRM suggested method in the interpretation of test results, the best way for modulus calculation is the depiction of stress-strain curves and measuring the slope of these curves. With regard to the capabilities of sophisticated numerical methods, which enable the consideration of PLT governing boundary conditions, a combination of standard in-situ tests and 3D numerical modeling is recommended for the in-situ characterization of rock masses for important projects.  
This research received no external funding.  
Not Applicable.  
The study did not report any data.  
The author declares no conflict of interest.
# A Location-Aware Waypoint-Based Routing Protocol for Airborne DTNs in Search and Rescue Scenarios
## 5 Performance Evaluation
### Simulation Scenario  
The search and rescue scenario is a common and relevant context for UAV adoption. Trying to mimic a realistic mission objective, we took inspiration from Ref. [15] where UAVs are actively searching for a target which is located on the ground. Realistic scenarios embodying this _modus operandi_ are natural disaster events (earthquake, hurricane, tsunami, etc.), where victims in dangerous or inaccessible areas need to be tracked and time is of the essence. In this context, human operators might be not capable of entering certain areas, hence employ UAVs to inspect them or UAVs are employed anyways to assist and speed up the tracking process.  
Under these settings, whenever a UAV has some relevant information about the search, it has to transmit the information to the base/control station, which might be located outside the search area. It might happen that no direct communication link to the base station is available and the only means to deliver the information is by relying on other nearby UAVs. On their turn, these UAVs might have different operational objectives, not necessarily related to the search operation. As an example, their focus is on a much larger operational area, containing the search one. In Figure 3 is provided a graphical representation of discussed search and rescue scenario.  
Modeling this scenario, we employ the _Random Waypoint_ (RWP) mobility model for the delivery UAVs. It is clear that all the waypoints of the RWP model are already planned at the start of the simulation, in order to simulate a planned path for each UAV. Communication wise, we adopt the 802.11 g standard as, with respect to other technologies, it offers an excellent tradeoff between coverage and bandwidth; in our previous test [22; 23; 24], we were able to communicate without packet losses up to 1.5 km. Energy wise, the electromechanical part of the drone is the most consuming one, hence employing another communication technology does not have a great impact on the final  
Figure 3: The simulated search and rescue scenario. In the white rectangle area the searching UAVs perform the search task and are confined within that area. The other nodes (delivery UAVs) are involved in other tasks, covering the larger gray area. The base station (BS) is located outside the scanning area, but within the larger area.  
outcome. Nevertheless, one can always make use of the low power modes offered by the IEEE standard. In Table 1 are exhibited all the simulation parameters.
# Towards the Implementation Process of Accessible Virtual
## 4 Accessible Virtual Compuses
### Discussion of Results  
There is an increase in the efforts made by HEIs, such as implementing strategies to consider regulations in order to generate accessible environments, and adapting physical spaces and curricula; however, at the Latin American level it is possible to see that universities are behind in the implementation of strategies to contribute to the creation of accessible virtual campuses. Some factors that influence the lack of sufficient conditions are the inadequate economic resources, in addition to a lack of trained personnel, which represents a problem in terms of disparity. In other more developed countries, such as the United States, implementing accessible virtual campuses is done by following accessibility standards, such as those proposed by the W3C.  
Despite having standards that imply universal design focused on accessible elements, it generally requires time to achieve adaptations and reach the goal of covering the requirements that arise from students, or adapting characteristics that still require attention to achieve accessible physical spaces and virtual platforms that involve the processes of the institution. Unlike Latin America, in the European region there is a constant increase in implementing strategies that comply with regulations and technological aspects, which helps students function naturally in the physical spaces and digital platforms of HEIs.  
By satisfying requirements with the development of accessible virtual platforms, teaching classrooms have been installed that attempt to break down technological and pedagogical barriers within the HEI; however, the development requirements need to be evaluated through metrics, interviews, evaluation instruments or questionnaires that gather information, in order to improve the interaction on the virtual platforms based on their experience and activities within the virtual campus.  
The research findings focus on the technical evaluation of existing tools, while disregarding processes or methodologies for the development of an accessible virtual campus. As such, there is a need for a suitable process for the creation of a virtual campus. Such a process should have its steps rooted in accessibility principles, in order to achieve an accessible virtual campus of high quality.
## 5 Analysis of Parameters Influence
### Pile Embedded Depth  
The pile embedded depth in the original design scheme is 6 m. This study set the pile embedded depth as 4 m, 8 m, 10 m and 12 m, when other parameters remained unchanged and compared the maximum surface settlement and the maximum lateral deformation of the retaining structure to analyze the influence of the pile embedded depth on the support effect.  
From Figure 13a,b, with the increase in pile embedded depth, the support effect of the retaining structure is stronger. When the embedded depth increased from 4 m to 6 m, the maximum surface settlement and the maximum lateral deformation of the retaining structure decreased by 30% and 48%, respectively. When the embedded depth increased from 6 m to 8 m, the maximum surface settlement and the maximum lateral deformation of the retaining structure decreased by 25% and 10%, respectively. The increase in pile embedded depth has a more obvious control effect on the maximum surface settlement. When the embedded depth exceeds a certain length, the influence on the lateral deformation of the retaining structure reduces.
## 4 Discussion
### Sub-Max Physical Load  
Recently, endurance sports such as triathlons have become increasingly popular. Triathletes are advised to do exercise at sub-max physical load for a long time to avoid reaching the fatigue state (ACP stage) [8], which confers a high risk of myocardial injury [9]. Moreover, heart complications during long-duration exercise in the ACP stage have been identified [10]. As humans continue to exercise during ACP, ventricular tachycardia or fibrillation might affect myocardial injury; in addition, left ventricular dysfunction or right ventricular overload may occur after exercise. Methods of avoiding ACP have caused widespread concern; this is a key research topic in exercise health care [12]. Even if ACP can be identified according to physiological signals, few methods of identifying sub-max physical load and avoiding ACP have been developed. The assessment of sub-max physical load can be judged by measuring 90% VO\({}_{2}\) max; however, VO\({}_{2}\) max measurement is uncommon and inconvenient.  
To the best of our knowledge, this study is the first study to introduce SampEn SV and SampEn CO as measurement methods. The results for SampEn SV and SampEn CO in Table 2 and those for BB reveal that these indicators are effective for differentiating the sub-max stage from the rest and ACP stages. Current technology has made it possible to perform non-contact breath testing, which is a remote breath detection method via radar. This is a method that does not require any wearable sensors, making it more comfortable and convenient for users. The transmission signal can even go through walls [47]. These results could be applied to wearable devices for assessing the physical load of a person to alert them if the ACP stage is reached, enabling them to stop exercising to avoid injuries and increase training efficiency.
# Photocatalytic Inactivation as a Method of Elimination of _E. coli_ from Drinking Water
## 3 Inactivation Process by Photocatalysts
### Metal Halides as Photocatalyst for the Inactivation of _E. coli_  
One of the metal halides that has been extensively studied for the inactivation of _E. coli_ is the silver halides. Silver iodide has been decorated on an organic framework made from 1,3,5-triformylphloroglucinol and 2,5-diaminopyridine precursors and was used for inactivating _E. coli_. The application of silver iodide as photocatalyst against bacteria was found to be a good option because of its stability after four consecutive runs without losing its photocatalytic performance [65]. To inactivate _E. coli_, silver iodide has also been used along with cerium oxide [66], copper ferrite [67], bismuth oxyiodide [68], zinc ferrite [69], bismuth stannate (Bi\({}_{2}\)Sn\({}_{2}\)O\({}_{7}\)) [70] and bismuth vanadate [70]. Silver bromide has also been an active photocatalyst against _E. coli_. [PERSON] et al. [70] utilized silver bromide decorated on graphitic carbon nitride to inactivate the bacteria in the presence of visible light. The effectiveness of silver bromide was obvious because 4.8 log of the bacteria was inactivated in the presence of silver bromide unlike 4.2 log that was inactivated when pure graphitic carbon nitride was utilized without silver bromide. More than 99% of the _E. coli_ was inactivated by silver bromide when it was used along with silver vanadate for bacteria inactivation in the presence of light in less than an hour [71]. In addition, the elimination of _E. coli_ by using silver bromide assisted with bismuth oxybromide has been reported [72]. The photocatalytic efficiency of silver bromide was boosted when it was used along with graphitic carbon nitride for eliminating _E. coli_[73]. [PERSON] et al. also reported the use of nanocomposite photocatalysts made from silver chlorides for the inactivation of _E. coli_. The photocatalyst was stabilized by amphopolycarboxyglycine, which is sodium-containing amphoteric surfactant [74].
## 1 Introduction
However, although the RD method results in smoother orbits of LEOs compared with the kinematic method [6], the a priori dynamic models (e.g., Earth's gravity, the ocean tide, solid tide, pole tide, and luni-solar gravitation) must be considered [11; 12; 13; 16]. In addition, the pseudo-stochastic parameters for the unknown dynamical parameters must be estimated. In this paper, a new RD orbit determination method (named the RD_STP method) is proposed. Based on [PERSON]'s equation of motion of the satellite, the second-order time-difference position (STP) only depends on the satellite's acceleration and the square of the sampling interval. Therefore, the STPs of LEOs can be integrated precisely with an a priori dynamic model (usually only the Earth's gravity field) and an a priori LEO orbit. Further, the integrated STPs are taken as additional dynamic \"pseudo-observations\" to constrain the GPS observations in the proposed RD_STP method. Different from the traditional dynamic/RD method, the unmodeled dynamic signals in the proposed method (e.g., luni-solar gravitation, tide forces, atmospheric drag, and the unknown dynamical parameters) are used as errors of the STPs to determine their stochastic model. Moreover, there are no pseudo-stochastic parameters to be estimated in the proposed method. The remainder of the manuscript is organized into four sections. Section 2 mainly focuses on the principle of the RD_STP method and its characteristics compared with the traditional dynamic/RD method. Section 3 presents the numerical results, including an accuracy analysis of the integrated STP pseudo-observations, and the POD results of the GOCE satellite based on the RD_STP method. Discussions and conclusions are presented in Section 4.
## 3 Results and Discussion
### Effects of Aspect Ratio of Elliptical Particle on the Effective Viscosity  
In this section, the relative viscosity contributed by a single particle with various aspect ratios and various distances from the walls is compared. Figure 8 shows the relative viscosity contributed by the elliptical particle with different aspect ratios for the various particle-wall distances. Note that the vertical axis scale is different for each figure for clarity.  
For all cases, contribution of the particle to the viscosity increases when particle flows near the wall. [PERSON] et al. [11] simulated the motion of confined circular particle in shear flow. They showed that the viscosity increases when the particle approaches the wall. Our results are consistent with their results. When the particle flows near the center line, the relative viscosity was almost independent of aspect ratio and confinement. For small particles, the relative viscosity was almost independent of aspect ratio. In a two-dimensional simulation, [PERSON] et al. [8] reported that the intrinsic viscosity of the elliptical particle is higher than that of the circular particle. Although some factors such as flow field conditions and particle concentration are different from theirs, a significant contribution to the viscosity due to particle shape was not confirmed in this study. In order to validate our numerical results, the intrinsic viscosity in three-dimensional conditions was calculated, and the results were compared with those from [PERSON] et al. [10]. Details of the simulation results are given in Appendix A.  
On the contrary, for larger particles, when the particle flowed near the wall, effects of particle shape on the relative viscosity became significant. The contribution of particles with high aspect ratio to the viscosity is minor when the particle flows near the walls. One of the reasons is that particles are oriented in the flow direction for a long time. In previous research, [PERSON] [27] investigated particle orientation under shear flow and reported that the effective viscosity decreases with higher aspect ratio. Our results are consistent with these results.  
Figure 7: Comparison of equilibrium position as a function of confinement with three different definitions.
# The Application of Spectral Entropy to P-Wave Detection in Continuous Seismogram Analysis
## 2 Materials and Methods  
### Dataset Collection from the IRIS  
This study is based on a seismic event dataset obtained from the IRIS (Incorporated Research Institutions for Seismology) database [16; 17; 18; 19]. The selected geographical region is located in Almaty, Kazakhstan (43.22\({}^{\circ}\) N, 76.92\({}^{\circ}\) E), with a coverage radius of 3.0\({}^{\circ}\) (333 km). This radius encompasses the city of Almaty, the Almaty region, and parts of neighboring countries, including Kyrgyzstan and China. The relative locations of the seismic stations were illustrated in our previous work [15]. The dataset includes records from seven seismic stations (TARG, ARLS, BAET, JNK, BTLS, SHLS, and TLG) spanning the period from The primary objective of this study is the detection of isolated P-wave arrivals using local entropy dynamics recorded independently at each seismic station. Given the spatial distribution of the network, each station captures seismic events based on its unique geographic position, local site conditions, and relative distance to the hypocenter.  
While the full operational durations and temporal coverage may vary across stations, entropy-based detection is applied uniformly within fixed-length windows centered on selected seismic events. This approach ensures that the analysis remains focused on the local signal dynamics rather than on long-term seismicity trends.  
Consequently, potential biases due to uneven coverage are not expected to impact the primary results of this study. Future work may incorporate additional normalization or weighting strategies for a large-scale consistency analysis, but such extensions are beyond the scope of the present event-specific detection framework.
# Energy-Efficient Hybrid Routing Protocol for IoT Communication Systems in 5G and Beyond
## 4 Proposed Methodology
### Route Maintenance  
In intra-cluster multi-hop topology, adjacent nodes can check out each other using short noticing messages. If a node does not respond, the adjacent node considers it to be dead. The adjacent node will exceed the dead node and transmit data to the next sensor node which has been listed on the received matrix from the central station. Considering the inter-cluster multi-hop topology, our proposed technique guarantees the delivery of data between the cluster head members even if one of the communication links fails (see Figure 5). This is due to the sub-optimal technique in the proposed technique.
## 1 Introduction
For these reasons, it would be very interesting to analyze the social thinking and local search abilities of PSO and CS in quadrotor control. The main contribution of our paper lies on using PSO and CS to improve results concerning the quadrotor full control. However, the CS algorithm suffers from a low convergence speed, since it uses a fixed step size over generations. To overcome this problem, [PERSON] et al. [28] proposed an adaptive cuckoo search algorithm (ACS) with adaptive step size. The ACS converges to a near optimum solution faster than CS algorithm. However, the problem of ACS algorithm is that it does not achieve better solutions compared to CS in most cases. In our work, we propose the cooperative PSO-CS algorithm that combines the ability of social thinking in PSO with the local search capability of CS. Such a cooperative process is likely to offer proper guidance for cuckoos to the global best positions and to ensure a balance between exploitation and exploration of the search space. Consequently, we are interested in examining if it is possible for us to improve results of quadrotor control by effectively integrating these two algorithms with complementary strengths. Our work treats position and attitude control in order to cover all topics in quadrotor control. For this objective, the control design includes six PID controllers: Three for angles (\(\phi\), \(\theta\), \(\psi\)) and three for positions (\(x\), \(y\), \(z\)). These controllers are optimally tuned using the heuristics PSO and CS, the cooperative PSO-CS and the classical method of Reference Model (RM). A comparative study is done to highlight the efficiency of the proposed intelligent controllers of PSO and PSO-CS. Indeed, their robustness is demonstrated in presence of wind disturbance. The rest of this paper is organized as follows. In Section 2, Newton-Euler formalism is used to establish the quadrotor dynamic model. In Section 3, the proposed algorithms of PSO, CS, the cooperative PSO-CS and RM are presented. In Section 4, the quadrotor full control is treated using PID controllers optimally tuned with the proposed methods. In the last section, our conclusions are given.