esa-sceva/satcom-chunk-collection huggingface dataset:
# Fast and Accurate Visual Tracking with Group Convolution and Pixel-Level Correlation
## 2 Related Work  
This section introduces the development of object tracking and some object trackers that have been reported in recent years. Object tracking algorithms can be divided into two categories: one is based on correlation filtering, and the other is based on deep learning. The methods based on correlation filtering include MOSSE [14], KCF [15], and DSST [16]. Correlation filtering introduces the convolution theorem from the signal domain to object tracking and transforms the template matching problem into a correlation operation in the frequency domain. This method is fast in operation but has average accuracy in complex scenarios. In recent years, with the development of deep learning technology and the establishment of large-scale datasets, object tracking algorithms based on convolutional neural networks have gradually emerged, among which Siamese network-based visual object trackers are particularly remarkable. A Siamese network consists of two sub-networks with the same structure and shared parameters, which are initially used for picture similarity analysis and metric learning. SINT [17] and SiamFC [1] first introduced Siamese networks to the visual object tracking field. SiamFC inputs the template picture and search sample, obtains the template feature map and search feature map, and then slides the template feature map over the search feature map as part of the correlation operation. The point with the largest response on the search feature map is considered the prediction target. SiamFC, as a fully convolutional network, has a simple structure and high tracking speed, and many subsequent works have been based on it. SiamRPN [2] introduced the RPN structure from object detection to the tracking field. One branch judges whether the object is in the foreground or background, and the other branch predicts the bounding box of the target. However, these algorithms only use shallow networks, and the tracking effect worsens for deep networks. Through the use of SiamRPN++ [3], it was found that the accuracy of deep networks is reduced because the strict translational invariance is broken, but allowing the target to be shifted in a certain range near the center point during training can alleviate the impact, enabling the successful application of deep networks in tracking algorithms. SiamFC++ [6] uses an anchor-free prediction head that does not set any anchor parameters, eliminating the effect of preset hyperparameters on the generalization ability of the algorithm. There are also some transformer structures used in visual object tracking that have achieved good results.  
Although these works achieved good results, the tracking accuracy decreases and the inference speed becomes slower in the face of occlusion, object scale changes, background clutter, and other situations. In this paper, we adopt feature fusion and some simplified methods for complex scenes to reduce the computational cost and improve accuracy at the same time, using pixel-level correlation to reduce the influence of background clutter and to refine the object bounding box.
# Unmanned Surface Vehicle Using a Leader-Follower Swarm Control Algorithm
## 3 Control Algorithm of the USV
### Swarm Control Algorithm
Assuming the formation that the follower USV is on the right side concerning the leader USV, the relationship between the turning radius of each USV and the formation control can be expressed in detail, as shown in Figure 8.  
As shown in Figure 7, to maintain the crossbar formation, the follower USV must move along a circle with radius \(r_{F}\). Furthermore, as the movement distance of the follower USV is larger, the movement speed of the follower USV should exceed that of the leader USV. Equation (15) shows the relationship between the turning radii of the leader and follower USVs. \[r_{L}=\left(d_{ref}\right)^{2}+\left(r_{F}\right)^{2}-2d_{ref}r_{F}\cos\left( \frac{\pi}{2}-\psi_{ref}\right) \tag{15}\]  
Here, \(d_{ref}\) is a straight line connecting any point within the turning radius of the leader USV and any other point within the turning radius of the follower USV. The \(\psi_{ref}\) represents the angle between \(d_{ref}\) and the turning radius of the follower USV. After Equation (15) is arranged for \(r_{F}\) and solved using the quadratic formula, it is expressed as Equation (16). \[r_{F}=d_{ref}\sin\left(\psi_{ref}\right)\ \pm\ \sqrt{d_{ref}{}^{2}\left(\sin \left(\psi_{ref}\right)\right)^{2}+r_{L}{}^{2}-d_{ref}{}^{2}} \tag{16}\]  
Both negative and positive values of the turning radius of the follower USV are shown in Figure 9.  
Figure 8: Relationship of the rotation radius and formation control. The two roots are divided according to the formation made by the leader USV and the follower USV. Therefore, the rotation radius \(r_{F}\) of the follower USV, considering whether the position of the follower USV is located on the left side or the right side of the leader USV, is arranged as shown in Equation (17). \[ \begin{array}{l}r_{F}=d_{ref}\sin\Big{(}\psi_{ref}\Big{)}\ \pm\ \alpha\sqrt{d_{ ref}{}^{2}}\Big{(}\sin\Big{(}\psi_{ref}\Big{)}\Big{)}^{2}+{r_{L}}^{2}-{d_{ ref}}^{2}\\ \alpha=1\ \text{if}\ r_{L}\ \geq\ r_{F}\\ \alpha=-1\ \text{if}\ r_{L}\ \leq\ r_{F}\end{array}  \tag{17}\]  
Here, \(r_{L}=v_{L}/w_{L}\) and \(r_{F}=v_{F}/w_{F}\) are the turning radii of the leader and follower USVs, and \(w_{L}=w_{F}\) to maintain formation. The speed adjustment of the follower USV is expressed as Equation (18). \[v_{F}=v_{L}+(r_{F}-r_{L})w_{L} \tag{18}\]  
Therefore, if the speed adjustment derived from Equation (18) is used to obtain the error value of the follower USV controller, formation control between the leader USV and the follower USV is possible even upon rotation. Detailed definitions of the variables and conditions of the rotation algorithm used in this study can be found in [24].
## 4 Results and Discussion
### Methane Desorption
The total amount of methane extracted at 50 \({}^{\circ}\)C from all three samples of the southern field in the Ptolemaida basin, considering the amount of CH\({}_{4}\) found in the 1.6 L of Ar gas channeled during the degassing process, was found to be 0.82 m\({}^{3}\)/kg. Taking into account the total lignite deposits (1.9 billion tons deposits) in the Region of Western Macedonia, Greece, the exploitable LCBM could reach comparable levels to those that have been reported for the region of Europe (7.7 \(\times\) 10\({}^{12}\) m\({}^{3}\) CH\({}_{4}\), [3]), showing a high potential for the sustainable exploitation of Greece's LCBM reservoirs. Considering that 1 m\({}^{3}\) of CH\({}_{4}\) can produce 4 kWh\({}_{\rm{el}}\)[43], the amount of methane stored in the area corresponds to a significant percentage of needs of the electric power production estimated for Greece [25]. Figure 7 shows the composition analysis of the produced gas at desorption conditions of 50 \({}^{\circ}\)C for the three tested samples. It was observed that the CO\({}_{2}\) content by volume dominates in a higher extent to the gas content of the South 53 (84%) and of the South Submerged (47%) samples, as compared to the gas content of the South T5 sample (24%). The South T5 sample was proved to have a higher CH\({}_{4}\) content by volume (2%) as compared to the South  
Figure 6: Methane quantity in ppm desorbed from 3 g sample during desorption experiments at (a) 25 \({}^{\circ}\)C, (b) 50 \({}^{\circ}\)C, (c) 100 \({}^{\circ}\)C, and (d) 150 \({}^{\circ}\)C.  
53 and the South Submerged samples. Moreover, the volume percentage of heavier hydrocarbons (propane and propene) of the South T5 sample was about 38%, which is higher than the 7.5% and the 26% in the South Submerged and South 53 samples, respectively. The knowledge of the exact gas composition of the gas inside deposits could empower the LCBM market to become technologically developed to preferentially extract the gases from deposits that have a higher content of heavier hydrocarbons (such as propane and propene), due to their higher calorific value than CH4 and their higher market value [44]. On the other hand, the CO2 that could be extracted in high quantities reduces the gas's market price and requires the use of expensive removal technologies such as water scrubbing, amino and alkaline solutions, membrane separation, cryogenic separation, or conversion to high added-value products [45]. Therefore, the LCBM extraction operation could be properly designed considering the economic benefits and the environmental impact of the process, based on the information about the identified components (CO2, CH4, and heavier hydrocarbons) of the adsorbed gas from the lignite deposits.
## 3 Experimental Results and Discussion  
To verify the effectiveness of the proposed method, we used C/C++, OpenSceneGraph (OSG), and a point cloud library (PCL) to carry out the experiments. The original oblique photography data had a large number of building models, and a certain building model was selected in this study for the experiment.  
The edge line of the selected building was restored to verify the effect of the edge line restoration method proposed in this paper. As shown in Figure 11, the comparison before and after restoration can realize the edge line restoration of the original model without pretreatment of the model, which has a good restoration effect, highlights the characteristics of the building edge line, and shows a better visual effect.  
Figure 11: Comparative diagram of before and after edge restoration.  
Figure 10: Rendering of local triangulation after edge line restoration. Green line is the edge line of the building model, and the white lines are TINs of the building model.  
Compared with the method mentioned in the introduction of this paper [25], for the test data with a range of only 500 m \(\times\) 500 m, it took 5-6 min to select a specific building and extract its edge feature line. The calculation time will be extended for a larger range of city-level aerial photos. This method adopted interactive feature line drawing, which can improve the rendering effect and operation efficiency of the existing amount of data, and is also the most cost-effective method. It can avoid excessive operation and performance consumption when extracting edge feature lines or possible errors, and can avoid the self-intersection problems of direct straightening and flattening of continuous triangulation. This method improved the operation efficiency while ensuring the same restoration effect.  
Compared with the simplex method of triangulation [26], for the test data with a photographing range of 500 m \(\times\) 500 m, on the premise of the interactive drawing of feature lines, a comparison between the time consumption and memory occupation of the two methods is shown in Table 1. This method was able to reduce the time cost and performance consumption of continuous triangulation topology reconstruction by two to three times; it improved the calculation speed and reduced the time required for restoration. According to the comparison between before and after the restoration of the building edge area, this method used the projection first, and then used the triangular patch cutting algorithm to restore the model, which was simple to operate, had low requirements for computer performance, and effectively improved the operation efficiency on the premise of ensuring the rendering effect.
# Investigating the Electro-Optic Response of Steroid Doped Liquid Crystal Devices
###### Abstract  
Nature is highly efficient at producing chiral compounds that are enantiomerically pure. The inherent chirality of naturally occurring biomolecules means that many have the potential to be used as chiral dopants for cholesteric liquid crystal (CLC) systems. Though many biomolecules have been identified as chiral dopants, many remain yet to be probed for their ability to function as chiral dopants. Here, 10 naturally occurring biomolecules comprised of steroids and bile acids were tested as chiral dopants for CLCs. Progesterone was identified as having high miscibility with nematic liquid crystals and was used in responsive liquid crystal devices. Progesterone-doped CLC devices were fabricated to exhibit either normal mode or reverse mode switchable behavior. Polymer stabilized CLCs (PSCLC) devices exhibiting dynamic electro-optic red- and blue-tuning behaviors were also fabricated. Furthermore, immiscible lithocholic acid was synthetically modified to afford two derivatives that were miscible at 10 wt. % in nematic liquid crystals. The two lithocholic acid derivatives were used as chiral dopants and incorporated into polymer stabilized CLCs which exhibited blue tuning behavior.  
cholesteric liquid crystals; chiral dopants; electro-optics; steroids; synthetic modification Article
# Adaptive QoS-Aware Multi-Metrics Gateway Selection Scheme for Heterogenous Vehicular Network +
## 3 Adaptive QoS-Aware Multi-Metrics Gateway Selection Scheme  
The proposed AQAGS scheme is used when the interest vehicles (IVs) located inside the LTE coverage area wish to communicate with the LTE network and no offloading media sources, such as Wi-Fi, Femtocell, or WiMAX are available to offload the LTE traffic. The primary focus is to prevent all IVs to directly communicate with the LTE-eNB due to the overload problem experienced by the LTE infrastructure network. Figure 1 shows the proposed system model used. The system model was based on HVN architecture, where VANET is integrated with an LTE infrastructure network. The LTE network is comprised of LTE base stations, called LTE-eNBs, connected to an evolved Packet Core (LTE-EPC). The LTE-EPC is responsible for communicating with the Internet. Each vehicle was assumed to be equipped with an OBU, which contains two network interfaces. One interface is dedicated to intervehicle communication in a pure ad hoc architecture using IEEE 802.11p technology. The second interface is for LTE-eNB communication. These two interfaces were assumed to be always active and can work simultaneously. This is possible due to their use of different, non-overlapping channels. We also assumed that each vehicle was equipped with a global positioning system (GPS), which allows it to decide its location and direction. The objective of this study was to select the IVs using the best method to connect to the LTE network. The IVs can define MGWs to communicate with the LTE-eNB, or they can directly connect to the LTE infrastructure network. This depends upon the residual load capacity of the LTE-eNB and the QoS requirement of the desired application.
## 3 Results
### Electrochemical Characterizations  
The depolarisation of the rebar was monitored on each prism (by checking that the steel/concrete system was in equilibrium with its environment) for the purpose of ensuring the validity of the electrochemical measurements.  
Following the depolarisation of the RC prisms submitted to the accelerated corrosion test, the half-cell potential (\(E_{corr}\)) was measured, and the corrosion current density was calculated. Rebar depolarization was observed to occur between 49 and 77 days after the end of the accelerated corrosion test.  
The results presented in Figure 8 indicate a decrease in half-cell potential with an increase in the duration of the accelerated corrosion test. Based on the probability of corrosion [48], as marked by the red dotted lines on the graphs, the rebars are likely to corrode in all the prisms regardless of the exposure time and the impressed current density. Conversely, the current density increases (from 1 to 10 \(\upmu\)A/cm\({}^{2}\)) with the duration of the accelerated corrosion test. In accordance with the corrosion levels (negligible, moderate and high) as recommended by [50], and indicated with red dotted lines in the graphs, all the corrosion current densities are indicative of a high corrosion level. From the literature, it is established that the appearance of concrete cracking is considered to occur at corrosion current densities exceeding 1 \(\upmu\)A/cm\({}^{2}\)[53].  
In conclusion, the presented graphs highlight that potential decreases and corrosion current density increase with total charge. Furthermore, these non-destructive electrochemical analysis results reveal corrosion and cracking in all the RC prisms, thus attaining the goal of the accelerated corrosion test. The remaining question to be addressed is whether the efficiency of the accelerated corrosion test allows for the generation of controlled cracks.
# Accurate Constant Phase Elements Dedicated for Audio Signal Processing
###### Abstract  
This review paper introduces real-valued two-terminal fully passive RC ladder structures of the so-called constant phase elements (CPEs). These lumped electronic circuits can be understood as two-terminal elements described by fractional-order (FO) dynamics, i.e., current-voltage relation described by non-integer-order integration or derivation. Since CPEs that behave almost ideally are still not available as off-the-shelf components, the correct behavior must be approximated in the frequency domain and is valid only in the predefined operational frequency interval. In this study, an audio frequency range starting with 20 Hz and ending with 20 kHz has been chosen. CPEs are designed and values tabularized for predefined phase shifts that are commonly used in practice. If constructed carefully, a maximum phase error less than 0.5\({}^{\circ}\) can be achieved. Several examples of direct utilization of designed CPEs in signal processing applications are provided.  
admittance function synthesis; audio effect; circuit synthesis; constant phase element; fractional-order; frequency response; ladder network; passive filter; zeroes and poles +
Footnote †: journal: Applied
## 4 Discussion
### DTPA-Extractable Soil Elements  
The critical levels of Fe, Zn, Cu and Mn found using the DTPA extraction method can vary between crops, but in different experiments described in [43], they were found to be close to 5, 1, 0.5, and 5 mg kg\({}^{-1}\), respectively. These critical levels are surpassed in all treatments (Figure 1). However, the MIN treatment with 1.9 mg Zn kg\({}^{-1}\) is approaching to the DTPA-Zn limit of 1.8 mg Zn kg\({}^{-1}\) for soils with a pH of 8, which was established in a more detailed experiment by [44]. Zinc figures justify the introduction of sewage sludges to prevent potential Zn deficiencies.  
Sewage sludge increased DTPA soil-extractable Cd, Cu and Zn and decreased Mn (Figure 1, Table A1), similar to the results obtained by [16] in calcareous soils. We disagree with [16] concerning the extractable Pb, as in our case, no differences were found between treatments (Figure 1, Table A1), although the maximum values were similar. The lack of Pb differences might be attributed to its adsorption onto the soil organic matter [8; 45]. In SNC and SPC treatments, higher soil-extractable Cd, Cu, and Zn than in the MIN treatment were observed. In fact, [PERSON] et al. [6] stated that SSs increased Cd availability (although they applied much higher N rates (from 382 to 1328 kg N ha\({}^{-1}\)), and in our experiment, it was observed despite the expected absorption in carbonates forms) [46].  
The increase in the DTPA extractability of Fe with SS treatments was followed by an inverse trend with extractable Mn. In iron, and in calcareous soils, extractable Fe is positively correlated with organic matter [47], and organic matter showed the highest values in the SPC and SNC treatments (Table 1). For the manganese, it has been described that its presence in SSs is highly bioavailable [5], but when applied, it is distributed and bound to carbonates [48]. Our data on extractable Mn (from 6 to 8 Mn kg\({}^{-1}\), Figure 1) approach the average obtained by [47] (9 mg Mn kg\({}^{-1}\)) in calcareous soils. Also, data from [47] match Zn values for MIN, although our figures for SNC and SPC were close to their upper limit of 5.6 mg Zn kg\({}^{-1}\). When comparing for iron, the SS treatments lead to available Fe concentrations above the maximum threshold of 12 mg Fe kg\({}^{-1}\) from [47], which is advantageous for soils of high pH, where Fe availability is always a constraint [49].
## 2 Related Work
### Modeling of Measurement Errors  
Traditionally, the localization measurement errors are modeled as Gaussian distribution random variables. However, several proposals in the literature addressed the problem of modeling localization error to provide better models in order to capture the measurement error behavior. Most of the work addressing this problem can be categorized into two categories: theoretical, as in the proposal in [18], which models the localization error by a uniform random variable distribution; and empirical, as in [19], which uses Received Signal Strength Indicators (RSSI) to build a Time of Arrival ranging error model. Simulation studies have also been used to analyze localization error in [20]. The aforementioned schemes focus on modeling the measurement error. However, no proposals addressed if the measurement errors in successive measurements over time are correlated or not, and the time correlation among the measurement error time series has not been modeled.
## 4 Discussion
Of the 330 patients included in the study, only 21 (6.36%) had implant failure, and of those, only 9 required revision surgery. This fact demonstrates that most patients, even those with mechanical failure, did not need revision surgery due to the absence of clinical complaints or neurological dysfunction. The ability to ambulate is a protective factor against material failure (RR, 0.27), and patients with neuromuscular scoliosis, excluding cerebral palsy as an etiology, are 3.33 times more likely to have mechanical failure than patients with idiopathic scoliosis (example,  
Figure 1: Lateral X-ray showing pedicle screw breakage at L5. Figure 2). This fact agrees with previous findings in the literature, in which patients with neuromuscular scoliosis or who do not ambate have higher rates of complications than those with idiopathic or congenital scoliosis [21; 22; 23]. Possible explanations for this fact are greater curve severity, poorer bone quality and nutrition, lower muscle mass, less subcutaneous and skin coverage, and more unfavorable clinical aspects, such as poor ventilatory function and recurrent infections, among other factors [24]. Among the limitations of the study, there was a high percentage of patients lost to follow-up according to the exclusion criteria, especially regarding correct and complete data in medical records and sufficient postoperative follow-up. The peculiarity of dealing with a heterogeneous sample population may make it impossible to fully generalize the findings. Another limitation is the fact that patients were operated on by different surgeons within the same institution. We cannot fail to mention the fact that the manufacturers of the implants used in the studied patients are unknown as a possible limiting factor in the study. It is possible that different materials have different technical and mechanical properties, although the overall number of implant-related failures is relatively low. Figure 2: Anteroposterior X-ray showing rod breakage on the right.