esa-sceva/satcom-chunk-collection huggingface dataset:
# Risk-Aware Wireless Positioning in
###### Abstract  
The evolution of wireless communications systems has promoted various applications that require user positions in various environments including indoor, maritime and aerial environments. This progress has also brought advanced wireless location tracking (i.e., positioning) schemes for many purposes such as military, accident prevention and facility management. In this paper, we propose a risk-aware wireless positioning scheme, where the position information is required for safety. Especially for the maritime environment, we model the risk of the user at each position as a function of location accuracy, geometry, ocean current speed and so forth. Considering the power budget of each user, we optimize the user's wireless positioning signal frequency (i.e., the positioning signal broadcasting rate) at each position so that our positioning scheme can minimize the average risk for each user.  
wireless positioning; maritime safety; risk; power budget Article
## 3 Results and Discussion
### Identification of Microorganisms, Phylogeny, and Predominance
cultures modulated the presence of the species, _Hansenispora uvarum_ C1 was present only in the fermentation of the P2 variety when _K. lactis_ B10 was used as the starter culture. The same behavior was observed for _P.luyveri_ C5, identified only in the CP variety and in the yeast inoculated treatments. Despite the phylogenetic proximity of the identified _P.luyveri_ strains, the C4 and C6 strains were present only at the beginning and end of fermentation, respectively, and in the coffee varieties CA62 and P2. Regarding the presence of the genus _Torulspora_, strain C13 was present throughout the fermentation process of treatments N and _K. lactis_ B10 and only in varieties A and CP, while strains C16, C14, and C15 were only present at 24 and 48 h and the beginning of fermentation, respectively. _Rhodosporidiobolus ruminae_ strain C8 was identified only during the initial fermentation of the CP and A varieties, along with microorganisms of the genus _Rhodotorula_. These yeasts have already been reported to be involved in wet coffee fermentation and may improve sensory properties by producing volatile compounds and inhibiting the growth of ochratoxigenic filamentous fungi [10; 11; 14] (Figure 3). Analysis of the presence of bacteria revealed that _Bacillus_ (C18, C20, C22, and C23), _Staphylococcus_ (C19 and C17), and _Lactococcus_ (C24) were present in the fermentation process of the coffee varieties. On the other hand, _Weissela_ sp. (C25) was present only in the inoculated treatments and in the CP variety. In the _S. cerevisiae_ CA11 inoculation, it appeared only at 24 and 48 h. The opposite behavior occurred for the inoculation with _K. lactis_ B10, where it appeared only at the beginning of fermentation. This behavior suggested that inoculation may have favored the growth of this bacterium in the presence of yeasts. In addition, the presence of this genus in coffee fermentation has already been reported in the literature; in addition to contributing to the quality of the fermentation process through the production of lactic acid, it also contributes to the inhibition of the growth of filamentous fungi [11; 14].
# YOLOv5-Sewer: Lightweight Sewer Defect Detection Model
## 2 YOLOv5-Sewer Network Design  
### Related Works  
YOLOv5s is a lightweight model within the YOLOv5 framework. Many studies on sewer defect detection are based on YOLOv5 [2; 17; 20; 21; 22]. This paper introduces a novel and lightweight sewer defect detection model named YOLOv5-Sewer, based on the improved YOLOv5s, specifically designed for the recognition of eight types of defects commonly found in sewer systems. These defects encompass cracks, utility intrusion, obstacles, joint offset, debris, holes, buckling, and roots. The proposed model adopts MobileNetV3 block [23] stacking as the backbone network, aiming to reduce the model size and associated detection equipment costs. To further enhance the speed and accuracy in pipeline defect detection, the paper introduces the C3-Faster module, based on Point Convolution (PConv) and a FasterNet block [24; 25], replacing the original C3 module in YOLOv5s.  
Addressing the challenge of dark sewer backgrounds, the paper incorporates a convolutional block attention module (CBAM) [26] and channel attention (CA) [27] to mitigate their impact on the model. Moreover, the Efficient Intersection over Union (EIOU) localization loss function [28] is employed to enable the network to adapt effectively to multi-scale sewer defects. The experimental results validate the effectiveness of the proposed YOLOv5-Sewer model, demonstrating its capability to achieve lightweighting with high accuracy in sewer defect detection tasks.
## 2 Operation and Control
### Communications and Automation
#### 2.2.1 Advanced Metering Infrastructures  
Basically, bidirectional communication between the utility and the \(SM\) is due to the presence of the AMI. The main objective of AMI is to provide data in real time, as well as decision-making by consumers. The first step towards the achievement of an effective AMI is the substitution of the classic energy meters by the SMs. However, the presence of AMI implies a new risk for the SG.  
Although there is no single solution, the research projects propose numerous architecture solutions for SG, and all of them supported by AMI, as shown by [PERSON] et al. [24]. It is possible to ensure that AMI is the key piece for the development of the SG.  
The existence of millions of SM processing information in the AMI, makes this a typological example of a cyber-physical system (CPS). Confidentiality and integrity require a robust encryption system in the keys.  
With respect to AMI, [PERSON] et al. [25] introduce AMI technology and its current status and its connection with advanced distribution operations (ADO), advanced transmission operations (ATO) and advanced asset management (AAM). [PERSON] et al. [26] present AMI, monitoring and automation of substations, power network monitoring, home automation networks (HANs), DR and integration of DG, which have been identified as \"Critical Applications\". These types of applications are essential for optimal management and control of the infrastructure.
# Human Factor Issues in Remote Ship Operations: Lesson Learned by Studying Different Domains
## 4 Results
### Cultural and Linguistic Problems  
Communication challenges and misunderstandings during the interaction between autonomous and unmanned vessels with manned vessels might occur due to bad communications [7] and the organizational climate. This issue was highlighted by [PERSON] et al. [31] as a working atmosphere which comprises structure, policies and culture within the organization. The organizational climate, which refers to the atmosphere of the organization which encompasses relationships, cultures, policies, and command and control structures. Past research suggests that problems with organizational values and culture have led to UAV accidents [16; 64].  
Making and protecting a human-centric culture is the way to create a peaceful atmosphere in an organization [16; 64]. The study of the Nogales UAS accident showed that a culture of _\"working around\"_ previous failures was a factor. This culture led to the poor documentation of maintenance procedures, which created a lack of adequate information about the corrective process [32]. In relation to UAV operation, [38] a _\"model aircraft culture\"_ was identified, in which radio control hobbyists usually perform operating and maintenance processes without formal checklists or procedures. They conclude that this culture must be changed if hobbyists are to join the UAV industry through the provision of training to change their habits and work culture.  
The research suggests that cultivating an effective culture and sufficient linguistic skills among the teams that operate in SCCs is vital for the safety of remote ship operation. Whereas onboard crews travel based on the voyage-plan and are more familiar with differ ent cultures and languages, remote ship operations will confront cultural and linguistic challenges that are not present in onboard operations.
# Trace Elements and Mineralogy of Upper Permian (Zechstein)
## 3 Previous Geochemical Studies of Zechstein Potash-Bearing Deposits in Poland
### K-Mg Salts of PZ2 (Stassfurt) and PZ3 (Leine) Cyclothems from SALT Domes in Central Poland  
The potash-bearing deposits of PZ2 and PZ3 cyclothems (Table 1) formed the stock parts of many salt domes in the central Poland area (Figure 1).  
Early studies of the Zechstein salts in the Klodawa salt dome (Figure 1) determined boron and bromine content of 0.01-0.092% and 0.2%, respectively [76], in the potash-bearing deposits.  
Subsequent studies of salt reserves for this dome showed varied content values of such trace elements as Br, B, Mn, Cs, Li, and Sr in the K-Mg salts of PZ2 cyclothem [33; 34; 77]. In the potash-bearing complex of PZ3 cyclothem, Br content was reported from 160-1050 mg/kg [34] to 1232 mg/kg [77], B--75.6-438 mg/kg, lithium (Li)--5.6 mg/kg, rubidium (Rb)--8.1 mg/kg, and strontium--16.1 mg/kg [77]. Analyses of potash-bearing deposits of PZ2 cyclothem in 2005-2007 documented a Br content of 77-1840 mg/kg and in the analogous complex of PZ3 cyclothem of 273-376 mg/kg (see: [50; 78]). Selected geochemical analyses of the Younger Potash (K3) deposits showed Br content of 110-4500 ppm and of Rb--0.9-5915 ppm [39; 40].  
Bromine analyses of both potash-bearing complexes in the Gora salt dome (Figure 1) documented its content of 59-651 mg/kg for Transitional beds Na2+K2 of PZ2 cyclothem and 234-649 mg/kg for PZ3 cyclothem [79].  
Both potash-bearing deposits in the Mogilno dome (Figure 1) were analysed for content of Br [52; 53; 80] and Al, Fe, Zn, Ni, As, Li, I, and Cd [53]. Bromine content in core samples from the M-24 borehole [80] showed in the Transitional beds Na2+K2 at 70-232 mg/kg (average: 139 mg/kg), in the Older Potash (K2)--at 69-238 mg/kg (average: 164 mg/kg), and in the Younger Potash (K3)--at 146-308 mg/kg (average: 226 mg/kg). Other bromine data from the Older Potash (K2) unit in the M-29 borehole were 69.4-148.7 mg/kg [52].  
The Younger Potash (K3) rocks in the Lanieta dome (Figure 1) contained the following elements: Rb--17-33.7 ppm, Br--181-210 ppm, I, Li and vanadium (V); 0.1-1.2 mg/kg, manganese (Mn), chromium (Cr) and copper (Cu); 2.5-7.2 mg/kg, B, Sr, caesium (Cs), cobalt (Co) and nickel (Ni); and 25-60 mg/kg and iron (Fe): >100 mg/kg [39; 40].
## Materials and Sensor Fabrication
### Fabrication of Fabric-Based Strain Sensor  
Although the rGO-coated fabric can be produced by coating GO followed by reduction, the toxicity of most reducing agent lowers the wearing safety of the obtained fabric. Therefore, we directly coated the fabric with rGO. To avoid the agglomeration in high-concentration rGO dispersion, \(N\),\(N^{\prime}\)-(cyclohex-2,5-diene-1,4-diylidene) bis (2-hydroxy-\(N\)-(2-hydroxy-3-(4-(trihydroxysilyl)butoxy)propyl)-3-(4-(trihydroxysilyl)butoxy)propan-1 -ami-num) (TSiPD) dispersant synthesized according to the procedures in [35; 36] was used. Meanwhile, since ample amounts of silanol groups were introduced by TsiPD, the dehydration condensation between the silanol groups and hydroxyl groups of the cotton fibers made rGO strongly adhere to the fiber surfaces.  
A 5 mg/mL graphene oxide solution was prepared by adding graphene oxide into deionized water. After homogeneously dispersing GO under a 40 kHz ultrasound environment, hydrazine hydrate solution was added to the graphene oxide solution via a dropper. Then, the mixed solution was placed in a water bath and heated at 90 \({}^{\circ}\)C for 2 h for hydrothermal reduction. Finally, mixing the GO solution and the TsiPD solution followed by sonication produced a homogeneous mixture of TsiPD and rGO. Similarly, the mixture of TsiPD and MWCNTs dispersion was obtained by adding MWCNTs into the TsiPD solution, sonicating for 10 min, and standing for 1 h.  
After pretreating the nylon spandex fabric by alternate sonications in ethanol and deionized water, the conductive fabric was fabricated through three dip-coating steps which are schematically shown in Figure 1. During the first dip-coating, the nylon spandex fabric was immersed in the MWCNTs-TsiPD mixture under ultrasonic environment. After 10 min immersion, the fabric coated with MWCNTs networks was taken out and dried in a 70 \({}^{\circ}\)C blast oven for 30 min. For the second dip-coating, immersing the fabric in the rGO-TSiPD mixture was performed in the same manner as the first dip-coating. In order to create microfolded rGOs structures, we stretched the obtained rGO/MWCNTs fabric up to the strain of 50%, and fixed two ends of the stretched fabric on a glassware with transparent tape. Successively, the second rGO film was generated by immersing the stretched fabric in the RGO-TSiPD mixture again. Finally, the conductive fabric was obtained by releasing it to its original state. Based on the obtained conductive fabric, a MWCNTs/rGO/rGO strain sensor can be obtained by coating conductive silver paste, leading out the wires.  
In general, the greater the pre-stretch, the more micro-folded rGO structures in the conductive fabric. However, when the stretching range is too large, the violent deformation, resulting to a long recovery time during releasing the fabric, reduces the dynamic response of the sensor. Through many trial experiments, it was found that the strain sensor obtained with the pre-tensile strain of 50% achieves a good compromise between the dynamic and the static performances.
# Rectangular Microstrip Array Feed Antenna for C-Band Satellite Communications: Preliminary Results
## 1 Introduction
Meanwhile, the parabolic reflector for collimating the radiation from the feeder antenna increases the gain performance. The fabricated 2 \(\times\) 2 microstrip array antenna has a 3.8-4.4 GHz bandwidth and a gain of 12.1 dBi at a frequency of 4.148 GHz. Moreover, we believe that combining the microstrip array antenna with a parabolic reflector results in an improved gain and maintains the reasonable dimension of the antenna system. In this work, using simulation, we assess the effect of the reflector on the designed microstrip antenna and discover a gain improvement of about 21 dB. Therefore, our designed antenna system meets the gain requirement for satellite communications. Furthermore, the proposed antenna system is competitive because of its low cost, low profile, and compactness due to the combination of a low-cost feeding antenna and the widely used parabolic reflector. The rest of this paper is organized as follows. The design of the microstrip antenna, including the fabricated antenna and the results of simulation and measurement, is covered in Section 2. The simulation results of the combination of the proposed microstrip antenna and the parabolic reflector are shown in Section 3. Finally, Section 4 concludes this paper.
## 2 Materials and Methods
### Rheological Properties  
The rheological properties of the control suspensions prepared using flours from raw (G, T, S and TT) or germinated grains (gG, gT, gS and gTT) and of the corresponding sourdough samples (G_SD, T_SD, S_SD and TT_SD prepared out of G, T, S and TT flours, and gG_SD, gT_SD, gS_SD and gTT_SD prepared out of gG, gT, gS and gTT flours) were measured using a controlled-stress rheometer (AR2000 ex, TA Instruments, Ltd, New Castle, DE, USA) equipped with a Peltier temperature control system, and a plate-plate geometry (diameter of 40 mm). The closing gap was set to 2 mm and a solvent trap was used to avoid moisture loss during rheological tests.  
For each sample the linear viscoelastic region (LVR) yield point was first identified through running stress sweep tests under oscillatory flow in small amplitude conditions, by increasing the stress values from 0.01 to 100 Pa, at an oscillation frequency of 1 Hz. The obtained data were used to determine the stress domain where the structure of the sample remained unaffected, known as the LVR. The intersection of the storage and loss moduli (G\({}^{\prime}\) and G\({}^{\prime\prime}\)), corresponding to the minimal stress value required for the proper beginning of flow, was also estimated [17]. Further dynamic frequency sweep tests were performed within LVR, at a constant oscillatory stress of 0.1 Pa. The working temperature was set at 20 \({}^{\circ}\)C for the stress and frequency sweep tests.  
In order to study the structure changes induced by heating in the suspensions and sourdoughs, temperature ramp tests were carried out in quasi-static conditions (frequency of 1 Hz, oscillatory stress of 0.1 Pa) by increasing the temperature from 20 to 90 \({}^{\circ}\)C by 1.5 \({}^{\circ}\)C/min. The samples were further maintained at 90 \({}^{\circ}\)C for 10 min. The temperature-induced gelatinization of the studied samples was estimated using the procedure proposed by [PERSON] et al. [18]. The gelatinization temperature range was determined by calculating the first derivative of the third order equation used to fit the G\({}^{\prime}\) vs. temperature values, in the area where inflection was observed. Only equations with r\({}^{2}\) approaching unity were considered proper for estimating the gelatinization temperature domain.
## 3 System Design Overview
### Technology and Method Selection
#### 3.6.1 Blockchain Framework Selection  
The platform employs Hyperledger Besu, an Ethereum-compatible permissioned blockchain, to balance decentralization with governance control. Hyperledger Besu is chosen over fully public blockchains like Ethereum due to its lower transaction costs, enterprise-grade security, and flexibility in defining access control policies. The permissioned nature of the blockchain ensures that only verified participants (innovators, mentors, and stakeholders) can validate transactions, reducing the risk of spam and fraudulent activity.  
Additionally, InterPlanetary file system (IPFS) is used for decentralized storage of intellectual property, business proposals, and NDAs, ensuring data availability while maintaining privacy. IPFS is selected over traditional cloud storage due to its tamper-proof nature and cryptographic content address, which prevent unauthorized data manipulation. Blockchain stores cryptographic hashes of IPFS files, ensuring data integrity while keeping large files off-chain to maintain efficiency.
# Propulsion Performance of the Full-Active Flapping Foil in Time-Varying Freestream
## 3 Results and Discussions
### The Mechanism of the Time Varying Freestream
Referring to Figure 11, the pressure distribution of the flapping foil at \(\tau=0\), 0.2 and 0.8 is shown in Figure 12. We note that the pressure distributions on the upper surface of the foil for different oscillating frequencies are almost the same. However, there is a clear difference in the pressure distributions on the lower surface of the foil for different oscillating frequencies. Figure 10: The evolution of the instantaneous thrust coefficient and freestream velocity over three periods for \(\hat{f^{*}}=0.68\), \(\theta_{0}=60\). The instantaneous velocity of the lower surface of the foil for \(\tau=0.8\) is more significant than \(\tau=0\) and \(\tau=0.2\), as shown in Figure 11. The strength of the corresponding negative pressure region on the lower surface of the foil for \(\tau=0.8\) is greater than \(\tau=0\) and \(\tau=0.2\), which increases the resistance of the flapping foil, as shown in Figure 10.  
Figure 11: The snapshots of the vorticity contours and velocity contours for \(f^{*}=0.68\), \(\theta_{0}=60^{\lx@math@degree}\), \(t=15.15T\), (**a**) \(\tau=0\), (**b**) \(\tau=0.2\), (**c**) \(\tau=0.8\). Figure 12: The pressure distribution of the flapping foil at different oscillating frequency coefficient for \(f^{*}=0.68\), \(\theta_{0}=60^{\lx@math@degree}\), \(t=15.15T\)  
According to Equation (3), we note that the oscillating frequency coefficient of the time-varying flow determines the fluctuation of the instantaneous velocity. When \(\tau=0.2\), the instantaneous velocity for \(t=15.35T\), \(16.35T\) and \(17.35T\) are \(2.79\) m/s, \(2.41\) m/s and \(2.39\) m/s, respectively, as shown in Figure 10. The three snapshots of the vorticity contours and the corresponding velocity contours for \(\tau=0.2\) at different simulation times are shown in Figure 9:0 The corresponding pressure distribution of the flapping foil is shown in Figure 9:1 Due to the little fluctuation range of the time-varying flow, the vortex topology of the flapping foil at a different time is slightly different. However, the velocity distribution near the foil can also be observed. The velocity of the leading edge of the flapping foil at \(t=16.35T\) is slightly greater than \(t=15.35T\) and \(17.35T\), as shown in Figure 9:2 According to the Bernoulli equation, the intensity of the negative pressure region generated by the leading edge of the lower surface of the flapping foil at \(t=16.35T\) is greater than \(t=15.35T\) and \(17.35T\), as shown in Figure 9:3 The strong negative pressure region at the leading edge of the flapping foil increases the thrust. Referring to Figure 10, we note that the maximum value of the instantaneous thrust coefficient at \(t=16.35T\). We can conclude that the time-varying flow affects the pressure distribution of the flapping foil. However, its impact on the propulsion performance of the flapping foil is also related to the relative position between the negative pressure area and the foil.
## 5 Analysis of Numerical Results  
### Comparison of Simulation Results  
Figure 6 shows the measurements and simulations of the temperature at the temperature measurement holes, focusing on soil layers at depths of 3 m (fine sand layer) and 11 m (medium sand layer). When comparing the measurement results between the T1 and T3 temperature measurement holes with the numerical calculation results, a consistent temperature change trend could be observed, with an error of \(\pm 2~{}^{\circ}\)C. Based on these findings, it is reasonable to conclude that the numerical simulation results of the temperature field were in good agreement with the field measurements. Utilizing a 3D numerical calculation model is feasible for studying the temperature-field evolution in frozen open-excavation sections of inclined shafts.
# Broadband DOA Estimation by Exploiting DFT Extrapolation
## 4 Discussion  
This study proposes a broadband DOA estimation method exploiting DFT extrapolation. We applied this method to the lower band to reduce the beam width in the spectral domain and improved the high-resolution property and accuracy of the estimated DOA. The received signal from randomly chosen DOAs was extended to the signal detected using the virtual 36-element array. To verify the effectiveness of the proposed algorithm, we compared the RMSEs of the DOA estimated from a 12-element array, a 12-element array extrapolated to 36-element array, and a 36-element real array at frequencies ranging from 500 MHz to 3 GHz. It was demonstrated that DFT extrapolation improved the estimation accuracy by lowering the RMSE throughout the frequency band and enabled the estimation of the DOA in the lower frequency band, which will broaden the frequency band at which an array with a relatively small number of elements can accurately estimate the DOA of a small number of sources.  
Conceptualization, E.S., Y.-s.C., S.K., C.P. and J.O.; methodology, E.S., Y.-s.C., S.K., C.P. and J.O.; software, E.S., Y.-s.C., S.K., C.P. and J.O.; writing--original draft preparation, E.S., Y.-s.C., S.K., C.P. and J.O.; writing--review and editing, E.S., Y.-s.C., S.K., C.P. and J.O. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the Agency for Defense Development by the Korean government (UD200042 ED).  
Not applicable.  
The authors declare no conflict of interest.