esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Multi-Motor Power Distribution Control Strategy
### Motor Power Regulation Curve Design  
To ensure the synchronized operation of each motor, this study employs a neighbor coupling control strategy. During the control process, each motor's speed is regulated using the neighbor coupling control strategy. The speed difference between the previous motor and its own speed serves as a feedback input to the sliding film speed controller. The current inner loop adopts the vector control strategy based on \(i_{d}=0\), and the control algorithm adopts the PI algorithm.  
Under the vector control strategy, according to Equation (5), the output power of the motor power can be realized by controlling \(i_{q}\). Therefore, under steady-state operating conditions, the load power of the distributed permanent magnet direct drive belt conveyor can be obtained according to the output power of each motor. The sum of the total power of the running motor is calculated as follows:  
\[P_{\text{zwe}}=\frac{P_{sum}}{s^{\prime}} \tag{16}\]  
When the permanent magnet direct drive belt conveyor runs in a steady state, the optimal number of motors is calculated according to the fuzzy controller, which is recorded as the running motor. According to Equation (16), the total power of each operating motor is calculated, and the average distribution principle is used to calculate the q-axis current value feedback to the current loop.  
\[i_{q\;sum}=\sum_{i=0}^{s^{\prime}}i_{qi} \tag{17}\]  
To mitigate the impact on the system resulting from the adjustment of the number of motors, the output power of the motor is gradually increased or decreased based on the sine curve defined in Equations (18) and (19). The curve of speed and acceleration is shown in Figure 8.  
\[i_{q}(t)=\left\{\begin{array}{cc}i_{q\;0}+\frac{\Delta i_{q}}{2}(1-\cos\frac {gt}{t_{a}}),0<t\leq t_{a}\\ \frac{i_{sum}}{s^{\prime}},&t>t_{a}\end{array}\right. \tag{18}\]  
\[i_{q}(t)=\left\{\begin{array}{cc}i_{q\;0}+\frac{\Delta i_{q}}{2}(-1+\cos \frac{gt}{t_{a}}),0<t\leq t_{a}\\ 0,&t>t_{a}\end{array}\right. \tag{19}\]  
where \(i_{q\;0}\) is the initial speed; \(\Delta i_{q}\) is the speed change value; and \(t_{a}\) is the adjustment time.  
Figure 8: \(Cont\).  
The output power of the remaining motor is adjusted according to Equation (20):  
\[p^{\prime}_{\text{are}}=\frac{P_{sum}-\sum\limits_{i=1}^{|s^{\prime}-s_{0}|}P_{i} }{s^{\prime}-|s^{\prime}-s_{0}|} \tag{20}\]  
According to Equation (5), the error between the current of each motor and the actual current is fed back to the current loop to realize the power distribution adjustment of each motor. The specific process is shown in Figure 9.
## 2 Materials and Methods  
Figure 1 shows the schematic and photo image of the designed WAVE antenna with closed-loop devices. In a current WAVE antenna without a closed-loop device, the height of the antenna should be greater than 50 mm because of weak radiated beam patterns [12; 13]. Contrastingly, by introducing a closed-loop device, the height of the WAVE antenna can be lowered to 9.97 mm. As the distribution of the surface current flowing to the ground is widened by introducing closed-loop devices to the ground, the disadvantage of the finite ground of the monopole antenna can be compensated. Additionally, it is effective in obtaining omnidirectional characteristics because they also act as a reflector for the radiated beams from the monopole antenna. Moreover, null points, where the minimum gain is below \(-20\) dBi in a monopole-only WAVE antenna, can be alleviated by introducing closed-loop devices.  
The width, length, and height of closed-loop devices were designed to be of 3.04, 5.00, and 2.90 mm, respectively, as shown in Figure 1a,b. The dimensions of the closed-loop devices were determined by considering the resonance and omnidirectional beam patterns in the operating frequency range of 5.850 to 5.925 GHz, used in the WAVE antenna. The height of the monopole antenna was designed to be about 9.97 mm (approximately0.24 \(\lambda\)), and the total length of each closed loop device was determined to be 13.84 mm (approximately 0.34 \(\lambda\)). To form a resonance between 5.85 and 5.925 GHz of the WAVE antenna's operational frequency and implement an omnidirectional beam pattern, the distance between the signal and closed-loop devices must be larger than 0.24 \(\lambda\). This is slightly smaller compared to previous reports, where the distance between the signal and the parasitic elements ranges from 0.3 to 0.4 \(\lambda\)[14, 15]. The proposed antenna was realized on the FR4 with a substrate (\(\epsilon_{\mathrm{r}}\) = 4.3, \(tan\delta\) = 0.025) of 0.8 mm thickness and signal and closed loop devices of 0.1 mm metal thickness.  
Figure 1c shows a photo image of the fabricated quadruple closed-loop devices introduced to the monopole WAVE antenna. The fabricated antenna was mounted on a shark-fin module for evaluation in the real environment. It comprised two LTE antennas and four designed antennas. Figure 1d shows a conventionally used monopole-only antenna without a closed-loop device, which was fabricated for comparison with the designed antenna.
## 4 The Phenomenon of Modal Coupling
### Top-Hysteresis Configuration (TC)
For intermediate intensities, the ratio approached the internal resonance condition 2:1, where the FRC around the first mode experienced a bifurcation and, instantaneously, the curve of the 2 DOFs system showed two peaks (\(I_{1}\) and \(I_{2}\)), in addition to the peak related to the second resonance (\(II\)), which was much  
Figure 5: TC2 oscillator close to a (2:1) internal resonance (\(\omega_{2A}/\omega_{1A}\cong 2.15\), \(\omega_{2B}/\omega_{1B}\cong 1.46\)): (**a**) FRCs of oscillation amplitudes of mass \(m_{1}\) for increasing intensity (\(a_{g}=[0.025\)–\(1.5\)]g), optimal excitation \(a_{g}=0.83g\) (red curve); (**b**) color map of the maximum response normalized to the excitation amplitude for different excitation frequencies and intensities (warm colors reveal peaks related to modes); (**c**) non-controlled (NC) and HVA responses at \(a_{g}=0.83g\); (**d**) Color map comparing the maximum displacements of NC and HVA oscillators (cold colors reveal amplitude reductions, warm colors relate to amplitude increments, and green is related to slight variations). smaller due to the distribution of excitation, the projection of which was limited on the second mode. In more detail, the \(I_{1}\) peak, corresponding to the first resonance frequency, doubled, following a trend that recalls the response of the VMTD and the previous TC1 system. However, unlike those cases, a typical bifurcation scenario of the nonlinear dynamic response was activated here. In fact, in the TC2 system, the rise of the \(I_{2}\) peak in the FRC is related to a novel superabundant mode generated by a bifurcation associated with an internal 2:1 resonance. An insight into this phenomenon is provided by the color map in Figure 5b, where, for different excitation amplitudes and frequencies, the resonance amplitudes of the \(m_{1}\) steady-state responses are evidenced. For small excitation amplitudes, two branches develop, starting from the two linear frequencies A. At the critical value of \(a_{g}=0.79g\), the novel mode related to \(I_{2}\) arises. For increasing excitation intensity, the value of peak \(I_{2}\) equals that of peak \(I_{1}\) at \(a_{g}=0.83g\) (red curve) and then prevails. Along the branch \(I_{1}\) the nonlinear modal shape evolves passing from the linear mode \(A\), for small excitation, to the linear mode \(B\), for high excitation, Figure 3c. Similarly, the nonlinear modal shape of the superabundant mode evolves reaching the linear mode \(B\), Figure 3c. At \(a_{g}=0.83g\), when the two peaks \(I_{1}\) and \(I_{2}\) are equivalent, the reduction in the vibration amplitude of the main structure reaches its maximum, about 80% with respect to the non-controlled case, Figure 5c. Then, the optimal excitation can be assumed as that which produces an extra peak \(I_{2}\), equal to the preexistent one \(I_{1}\) in the FRC of \(m_{1}\). For different forcing intensities, the hysteretic absorber mitigated the system vibrations as well: as shown in Figure 5d, the effectiveness of the HVA was maintained in a wide range of intensities and frequencies (blue regions).
# Miniaturized MIMO Antenna Array with High Isolation for 5G Metal-Frame Smartphone Application
## 3 Results and Discussion
### S-Parameters and Efficiency  
Thanks to the symmetrical arrangement of the MIMO antenna system, only the simulation and measurement results of the part of the antenna elements are analyzed and compared here.  
The simulated and measured S-parameter (reflection coefficient) results are given in Figure 13a. Due to manufacturing tolerances, the measured bandwidth is slightly offset, but the overall measurement results are satisfying. The measured impedance bandwidth can reach 12.7% within the acceptable range and the center frequency shifted to 4.82 GHz. The transmission coefficients between some ports (1 and 2, 1 and 3, 1 and 4, 1 and 5, 1 and  
Figure 11: Photographs of the fabricated MIMO antenna system. (**a**): Front view, (**b**): back view, (**c**): long side view, and (**d**): short side view.  
Figure 12: Photographs of the test site where the MIMO antenna was tested. (**a**): Vector network measurement analyzer and (**b**): SATIMO anechoic chamber.  
6, 2 and 3, 2 and 4, and 3 and 4) with relatively strong coupling are shown in Figure 13b. It is worth noting that the isolation degree is 2 dB higher than the simulation result because it is very difficult to weld the metal frame and the ground plane of the mainboard when the MIMO antenna system is manufactured, which is some gap. Overall, the isolation level between components exceeds 22 dB in the simulated and measured frequency bands.  
In Figure 14, the measured radiation efficiency of Ant 1 and Ant 3 is lower than the simulated result in the frequency band, and the peak of the center frequency is also slightly lower than the simulated value. This is due to the fact that during the test, in addition to manufacturing tolerances, the placement of the antenna system can also cause the loss of tangent of the FR-4 substrate to be non-uniform. However overall, the measured efficiencies of the Ant 1 and Ant 3 range from 50-73% (\(-\)3 dB\(-\)\(-\)1.37 dB) in the desired frequency band.
## 3 The Proposed Recommendation System
### Content-Based Filtering  
To examine the similarity between items, we use tf-idf, which is defined as Equation (1) [28; 29].  
\[tf-idf(t,\ d)=tf(t,\ d)\times idf(t,d), \tag{1}\]  
where \(t\) is a term, \(d\) is a document, \(tf(t,d)\) is the number of occurrences of \(t\) in \(d\), and \(idf(t,d)\) is the inverse document frequency. Simply put, tf-idf is the product of the term frequency and the inverse document frequency. The idf(t, \(d\)) is defined as Equation (2).  
\[idf(t,d)=log\frac{n_{d}}{1+df(d,t)}, \tag{2}\]  
where \(n_{d}\) is the number of documents in the data set, and \(df(d,t)\) is the number of documents that contain \(t\).  
For example, we assume that there are three simple documents:  
1. [PERSON] likes drinking.
2. [PERSON] likes drinking warm juice.
3. [PERSON] and [PERSON] like drinking cold water.  
The total word frequency can be summarized in Table 1.  
\begin{table}
\begin{tabular}{l c c c c c c c c} \hline  & **And** & **Cold** & **Drinking** & **[PERSON]** & **Juice** & **[PERSON]** & **Like** & **Warm** & **Water** \\ \hline Document 1 & 0 & 0 & 1 & 0 & 0 & 1 & 1 & 0 & 0 \\ Document 2 & 0 & 0 & 1 & 1 & 1 & 0 & 1 & 1 & 0 \\ Document 3 & 1 & 1 & 1 & 1 & 0 & 1 & 1 & 0 & 1 \\ \hline \end{tabular}
\end{table}
Table 1: An example of tf.  
However, instead of using raw term frequencies, it is typical to normalize data, such as L2-normalization, to get a vector of length 1. The L2-normalization can be calculated as Equation (3) [57].  
\[v_{norm}=\frac{v}{||v||_{2}}=\frac{v}{\sqrt{v_{1}^{2}+v_{1}^{2}+\cdots+v_{n}^{2}} }=\frac{v}{\left(\sum_{i=1}^{n}v_{i}\right)^{1/2}} \tag{3}\]  
Next, we measure similarities between items. In the context of tf-idf, an item can be considered a document for our data sets as shown in Table 2. There are numerous similarity measures in the data science field. Among them, we use the cosine similarity measure, which is calculated as Equation (4) [58; 59].  
\[cosine\ similarity=\cos(\theta)=\frac{A\cdot B}{||A||||B||}=\frac{\sum_{i=1}^{n}A _{i}B_{i}}{\sqrt{\sum_{i=1}^{n}A_{i}^{2}}\sqrt{\sum_{i=1}^{n}B_{i}^{2}}}, \tag{4}\]  
where \(A\) and \(B\) are two separate documents. The result of cosine similarity for our example is listed in Table 3. Note that, unlike the Euclidean similarity measure, the cosine similarity measure is scale-insensitive, and thus, it can be used for general use cases.
# VTG-GPT: Tuning-Free Zero-Shot Video Temporal Grounding with GPT
## 5 Conclusions  
This paper proposes a tuning-free framework named VTG-GPT for zero-shot video temporal grounding. To minimize the bias from mismatched videos and queries, we employ Baichuan2 for refining human-annotated queries. Recognizing the inherent redundancy in video compared to text, we utilize MiniGPT-v2 to transform visual inputs into more exact descriptions. Moreover, we develop the proposal generator and post-processing to produce temporal segments from debiased queries and image descriptions. Comprehensive experiments validate that VTG-GPT significantly surpasses current SOTA methods in zero-shot settings. Remarkably, it achieves a level of performance on par with supervised approaches.
## 3 Results and Discussions
### Effect of the Laser Pulse Number on the Fabrication of Nanostructures on BiIn-Si  
Figure 6 depicts the laser pulse number effect on the ripple structures. The laser fluence of the femtosecond laser was maintained at 2.55 J/cm\({}^{2}\). At a laser pulse number of 100, ripple structures were formed (Figure 6a), and a depth of \(\approx\)200 nm was obtained from the AFM image (Figure 6d). With the laser pulse number increasing to 200, the ripple structures became distinct (Figure 6b), with the depth reaching \(\approx\)300 nm (Figure 6e). When the pulse number was \(N\) = 300 (Figure 6c), the periodic structures were distorted due to heat accumulation [38]. Figure 6d,e shows that the depth of the ripple structures increased when the laser pulse number increased from 100 to 200. Nevertheless, when the laser pulse number was increased to 300, the depth did not increase because the ripple structures were damaged. The results indicate that the depth could be modulated by changing the number of laser pulses. However, the accumulated thermal energy must be less than the damage threshold.  
Figure 5: SEM images of the surface morphologies with a scan speed of 20 \(\upmu\)m/s on BiIn-Si. (**d–f**) are the magnified versions of the areas within the red rectangles of (**a–c**), respectively. P is the period of the ripples.  
Figure 6: SEM images and AFM profiles of the surface morphologies fabricated on BiIn-Si at a fixed laser fluence of 2.55 J/cm\({}^{2}\). (**a–c**) correspond to SEM images and (**d–f**) correspond to AFM profiles with different scanning speeds. \(N\) is laser pulse number.
# Ocean Remote Sensing Techniques and Applications: A Review (Part II)
## 2 RS Applications in Ocean
### Sea Ice (SI)
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**RS System** & **RS System (Type)** & **Advantage** & **Disadvantage** \\ \hline \multirow{8}{*}{Passive} & \multirow{4}{*}{Optical} & Availability of different optical RS systems, long time data archive, straightforward data interpretation & Data missing in cloud covered areas, only daytime imagery, thin ice and ocean surface spectral similarity, similar reflectance of snow and ice \\  & & Good discrimination between ice and ocean surface, can provide temperature data & Data missing in cloud- covered areas, difficulty in discriminating melting ice or newly formed thin ice and water at the freezing \\  & & Not limited by cloud cover and daytime, contain physical properties, almost daily global coverage, long time data archive & Very low spatial resolution, mixed pixel (different ice types and coastal areas), low energy and little details \\  & & Very good revisit time can be achieved by deploying several receivers & Low spatial resolution, extra facilities required to be deployed \\  & & Not limited by cloud cover or daytime, contains physical properties, high spatial resolution, Different data acquisition modes are available, ability to detect small leads, penetration capability & Difficult data interpretation, speckle noise, different ice types might have similar scattering behavior, similarity of wind roughened water and ice \\  & & Not limited by cloud cover or daytime, daily global coverage & Cannot obtain small details, very low spatial resolution, unable to provide image data \\  & & Almost daily global coverage, accurate topography for SI thickness measurement, ability to map small leads & Error due to the roughened sea surface, no physical characteristics \\  & & Any accurate result, 3D data availability & High cost of data, low data availability, no physical properties Limited data availability, not frequent observations \\  & & Not limited by cloud cover and daytime, long time data archive & Unable to provide images, signal loss in propagation into dense ice, unable to detect SI presence constantly \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Different RS systems for SI studies along with their advantages and disadvantages.
# New Materials and Effects in Molecular Nanomagnets
## 2 Single-Ion Anisotropies  
Single-molecule magnets can be prepared, amongst others, from lanthanides and actinides, such as the lanthanide ion Dy\({}^{3+}\), with some lanthanide elements being known to be part of the strongest recently known magnets [31]. SMMs based on such f-elements can show very high anisotropy barriers, blocking magnetization reversal, and have hysteretic behavior at significantly higher temperatures than other SMMs.  
In these SMMs, a strong magnetic anisotropy of the metal center plays the most important role for their magnetic properties. Necessary prerequisites for this are a doubly-degenerate ground state--to reach bistability of the ground state--and a high quantum number \(\pm m_{j}\)--leading to a high magnetic moment when the ground state is mostly populated [31]. This is generally the case for Dy(III) ions and, in a strictly axial crystal field symmetry, also for Tb(III) ions. Furthermore, a large separation between this bistable ground state \(\pm m_{j}\) and the first excited state is necessary, as the energy required for relaxation is often correlated with this separation.  
Calculating the 4f electronic structures for lanthanide ions and the corresponding optimum crystal fields, [PERSON] and [PERSON] theoretically explained the most often used axially-coordinated ligand environment that is optimum for Dy(III), and also suggested using Tm(III) and Yb(III) ions as part of SMMs [31].  
Design strategies based on crystal-field theory were suggested by [PERSON] et al., who suggested high-performance Ln-based SMMs with very slow magnetization relaxation, and discussed some representative Ln-SMMs with special local symmetries [32]. However, the authors also mentioned the challenges to realize the practical magnetic characterization of these high-performance SMMs.  
The role of the single-ion anisotropy is discussed in the literature by many other authors, e.g., as part of a synergic effect with magnetic exchange interactions [33; 34; 35].  
It should be mentioned that the aforementioned relaxation processes are less well understood in lanthanide-based SMMs than in SMMs containing transition-metal complexes. For Ln-SMMs, multiple relaxation pathways are mentioned, such as the reversal of thermally activated spins at high temperatures and tunnel relaxation at low temperatures, as well as spin-lattice relaxation or field-induced multiple relaxations, with a general tendency to show multiple relaxation processes, as is visible in two-step or even more complicated relaxation processes [36].
# Integrating a Path Planner and an Adaptive Motion Controller for Navigation in Dynamic Environments
###### Abstract  
Since an individual approach can hardly navigate robots through complex environments, we present a novel two-level hierarchical framework called JPS-IA3C (Jump Point Search improved Asynchronous Advantage Actor-Critic) in this paper for robot navigation in dynamic environments through continuous controlling signals. Its global planner JPS+ (P) is a variant of JPS (Jump Point Search), which efficiently computes an abstract path of neighboring jump points. These nodes, which are seen as subgoals, completely rid Deep Reinforcement Learning (DRL)-based controllers of notorious local minima. To satisfy the kinetic constraints and be adaptive to changing environments, we propose an improved A3C (IA3C) algorithm to learn the control policies of the robots' local motion. Moreover, the combination of modified curriculum learning and reward shaping helps IA3C build a novel reward function framework to avoid learning inefficiency because of sparse reward. We additionally strengthen the robots' temporal reasoning of the environments by a memory-based network. These improvements make the IA3C controller converge faster and become more adaptive to incomplete, noisy information caused by partial observability. Simulated experiments show that compared with existing methods, this JPS-IA3C hierarchy successfully outputs continuous commands to accomplish large-range navigation tasks at shorter paths and less time through reasonable subgoal selection and rational motions.  
autonomous navigation; dynamic environments; Deep Reinforcement Learning; geometrical path planner +
Footnote †: journal: Applied Sciences
# A Rapid Verification System for Automatic Emergency Braking Control Algorithm of Passenger Car
## 4 Verification of Passenger Car AEB Control Algorithm  
An AEB algorithm verification system for the passenger car was established, which is suitable for the rapid development and verification of the AEB control algorithm. To prove the practicability of the verification system, an AEB hierarchical control algorithm was used as a test example, and virtual AEB test scenarios under various test conditions were established according to the standard. The proposed verification system is used in SIL testing and HIL testing to verify and analyze the AEB hierarchical control algorithm.