esa-sceva/satcom-chunk-collection huggingface dataset:
# Optimization of Redundant Degrees of Freedom in Robotic Flat-End Milling Based on Dynamic Response
## 3 Milling Experimental Validation
### Posture Optimization Based on the Dynamic Response Index  
To enhance the quality of surface machining, the optimal redundant angle using the proposed modal for a slot along the y-axis direction is approximately 20\({}^{\circ}\), as shown in Figure 9. The chatter stability and dynamic characteristics of the robotic milling system are influenced not only by the redundant angle but also by the specific position. In this section, the feeding distance for each slot is kept short enough to approximate it as a consistent machining condition for verification.  
Figure 8: Acceleration power spectrogram with different redundant angles at point #2: (**a**) \(\gamma\) = 0\({}^{\circ}\) along \(x\)-axis direction, (**b**) \(\gamma\) = 0\({}^{\circ}\) along \(y\)-axis direction, (**c**) \(\gamma\) = 20\({}^{\circ}\) along \(x\)-axis direction, and (**d**) \(\gamma\) = 20\({}^{\circ}\) along \(y\)-axis direction.  
Instead of altering the tool position during the milling process, the aluminum workpiece is moved after each feeding to ensure that the robot follows the same path. For slot milling, various redundancy angles, such as \(-40^{\circ}\), \(-30^{\circ}\), \(-20^{\circ}\), \(-10^{\circ}\), \(0^{\circ}\), \(10^{\circ}\), \(20^{\circ}\), \(30^{\circ}\), and \(40^{\circ}\), are employed. The experiments are carried out with the same cutting parameters as shown in Table 1. When the posture of the robot changes during milling, the robot controller records the parameters of each joint angle for real-time monitoring, and the cutting force is measured using a Kistler 9255C dynamometer (see in Figure 10).  
The machined surface of the workpiece, as depicted in Figure 11, reveals significant insights. Figure 12 illustrates the measurement of the surface roughness of the workpiece using the Alicona optical 3D measuring instrument. A comparison of the measured values and the predicted results using the dynamic response index is presented in Figure 13 and summarized in Table 3.  
Figure 10: (**a**) Sampled trajectory of each robot joint with \(\gamma=0^{\circ}\), and (**b**) cutting force with \(\gamma=0^{\circ}\) (sampling frequency: 10 kHz).  
Figure 9: Milling experiments: (**a**) initial posture with \(\gamma=0^{\circ}\), and (**b**) optimized posture with \(\gamma=20^{\circ}\).  
Figure 11: Machined surface at different redundant angles.  
Figure 12: Optical surface roughness measurement instrument.  
Figure 13: Measured and predicted surface roughness of the robot slot milling at different redundant angles: (**a**) measured at \(\gamma=-40^{\circ}\), (**b**) predicted at \(\gamma=-40^{\circ}\), (**c**) measured at \(\gamma=0^{\circ}\), (**d**) predicted at \(\gamma=0^{\circ}\), (**e**) measured at \(\gamma=30^{\circ}\), and (**f**) predicted at \(\gamma=30^{\circ}\).
## 4 Results and Discussion
### Random Road Excitation
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Suspension Types**} & \multirow{2}{*}{**Body**} & \multirow{2}{*}{**Suspension**} & \multirow{2}{*}{**Tire**} & \multirow{2}{*}{**Control**} & \multirow{2}{*}{**ECcentricity**} \\  & **Accel-Ration** & **Deflection** & **Dynamic** & **Force (N)** & **Force (m)** \\ \hline Passive & 0.92 & 0.0046 & 647.7 & – & \(6.1\times 10^{-5}\) & 164.4 \\ Pra-dependent 0\% & 0.67 & 0.0045 & 819 & 103.3 & \(6.5\times 10^{-5}\) & 176 \\ Reliable robust 0\% & 0.61 & 0.0047 & 893.9 & 136.5 & \(6.9\times 10^{-5}\) & 187.5 \\ Pra-dependent 40\% & 0.77 & 0.0043 & 732.4 & 58.9 & \(6.1\times 10^{-5}\) & 166.1 \\ Reliable robust 40\% & 0.72 & 0.0043 & 761.4 & 74.6 & \(6.1\times 10^{-5}\) & 169.2 \\ Pra-dependent 80\% & 0.86 & 0.0044 & 671.1 & 19.5 & \(5.9\times 10^{-5}\) & 160.9 \\ Reliable robust 80\% & 0.85 & 0.0044 & 677.7 & 24.3 & \(5.9\times 10^{-5}\) & 161.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The RMS of EV dynamic responses with different actuator thrust losses and parameter variation. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Dynamics Response**} & \multirow{2}{*}{**Passive**} & \multicolumn{2}{c}{**Active Suspension**} \\ \cline{3-4}  & & **Kc** & **Kp** \\ \hline Sprung mass acceleration (m/s\({}^{2}\)) & 0.92 & 0.70 & 0.67 \\ Deflection of suspension (m) & 0.0046 & 0.0043 & 0.0045 \\ Dynamic force of tire (N) & 647.7 & 787 & 819 \\ Eccentricity (m) & \(6.1\times 10^{-5}\) & \(6.4\times 10^{-5}\) & \(6.5\times 10^{-5}\) \\ UEF (N) & 164.4 & 174.5 & 176 \\ Control force (N) & – & 90.97 & 103.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The root mean square (RMS) of electric vehicle (EV) responses. Figure 18: Body acceleration in electric vehicle: (**a**) under 0% actuator loss; (**b**) under 40% actuator loss.
## 1 Introduction
At the same time, the issue of comparing pieces on the basis of their graph representation has not been widely discussed so far. Unfortunately, none of the previously existing publications described calculating the similarity of the pieces, thus making it impossible to decide whether the considered music (e.g., generated arrangement) is innovative enough to be considered a separate piece, distinguishable from the original. In particular, no metrics have been defined to measure the distance of musical pieces based on their graph and network representation. Notwithstanding generating musical arrangements and attempts to compare them with the original pieces on the basis of their graph representation (e.g., [13; 14; 15]), no studies have been conducted dealing with this subject systematically. Using a critical analysis method, we point out why the current approach is insufficient. Therefore, we propose a new method of comparing musical pieces and analyze it quantitatively: by providing a series of experiments in order to verify its effectiveness. The aim of the article is to introduce a formal description and to study the operation of a new method for comparing musical pieces on the basis of their graph and network representation. The authors examine the results obtained for various scenarios of using the described method--it can be used to compare different musical pieces, classify them to a potential genre, compare different musical arrangements, and detect plagiarism. In particular, in the case of the latter two applications, the method achieves very good results, and this implies that it can be successfully used in the work of arrangers and anti-plagiarism control systems. The article introduces a novel and comprehensive method of checking if the compared pieces are similar to each other and to what extent they share the structure of connectionsbetween notes. In addition, by providing a single, numeric value of this similarity, this method remains untainted by the previous experience and \"musical proficiency\" of the human operator. Therefore, it may be used in a variety of applications: from purely musical (checking if the arrangement being created is still similar to the original piece) to legal (validating if the plagiarism was committed). The article comprises six sections. Section 1 is this introduction. In Section 2, the authors outline the background of the studies--they describe the field and the hitherto known approaches to solving the described issues. Section 3 contains a description of the authors' method of comparing graphs and networks and adapting it to the examined application. In Section 4, the authors describe the results obtained in a series of experiments. Section 5 summarizes the results obtained with the described method in the context of previous studies and potential applications. Section 6 sets out the final conclusions from the studies carried out.
# Genetic Engineering Approaches for the Microbial Production of Vanillin
## 4 Genetic Engineering Approaches
### Genetic Engineering in Model Microorganisms
#### 4.3.3 Engineering of Chassis
Thus, rapid strategies to increase vanillin resistance include vanillin recovery using adsorbent resins [133] or a solid-liquid two-phase partitioning bioreactor system [134]. In a recent study, [PERSON] et al. [135] screened aromatic compound transporter candidate genes from _P. putida_ to identify those whose were efficient substrate importers and product exporters in a _E. coli_ recombinant strain producing vanillin from ferulic acid. Then, based on the screening results, they constructed an autoregulatory bidirectional transport system by co-expressing the genes _todX_ (encoding a ferulic acid importer) and _pp_0179_ (encoding a vanillin transporter) under the control of the vanillin-inducible promoter _ADH7_ from _Saccharomyces paradoxus_[135]. This system significantly enhances the substrate uptake efficiency while alleviating the vanillin toxicity issue, thus allowing higher vanillin production.
## 3 Analysis of Experimental Results
### Mass Loss Rate  
Figure 4 displays the mass loss rate of self-compacting concrete with various RCA replacement rates. The pattern persisted along all curves. RCASCC demonstrated a change in the law of initially increasing and then dropping as the number of wet and dry cycles increased. The mass loss rate of each set of test specimens varied after the initial 30 wet and dry cycles. Due to the reaction of SO4\({}^{2-}\) in the first solution with the hydrates in the concrete, which produced compounds such as calcium alumina, which caused it to plug some of the pores in the concrete and improve the compactness, RCASCC-50 showed the biggest increase in mass damage rate of 1.68%. Because the larger recycled aggregate replacement rate reflects a larger porosity of the concrete, allowing the products from sulfate attack to continue to be stored in the concrete, the mass loss rate continued to increase for RCASCC-75 and RCASCC-100 when the number of cycles reached 60 while decreasing for the other groups. The specimens' overall mass loss rate began to reduce after more than 60 wet and dry cycles. After a sudden increase, the rate of mass loss for the specimens in the RCASCC-50, RCASCC-75, and RCASCC-100 groups reduced to 2.98%, 3.05%, and 3.59%, respectively.  
Figure 4: Mass loss rate of self-compacting concrete with recycled aggregates.  
Figure 3: Appearance of prismatic specimens after erosion. (**a**) RCASCC-0. (**b**) RCASCC-25. (**c**) RCASCC-50. (**d**) RCASCC-75. (**e**) RCASCC-100.  
Different RCA replacement rates can significantly affect the sulfate attack resistance of self-compacting concrete, as shown in Figure 4. The specimen's total water content and porosity increased when excessive RCA was applied in place of NCA. Increased amounts of SO4\({}^{2-}\) were absorbed into the concrete. As a result, sulfate attack significantly increased, which was bad for the concrete's ability to resist sulfates [30,31].
## 5 Conclusions  
In this paper, the influence of backscattered light on the phase noise has been firstly analyzed through theoretical derivation. The analysis results have shown that when the point source transmittance (PST) of the optical system is less than \(4\times 10^{-10}\), the phase noise generated by the backscattered light is less than 1 pm, which has met the requirements of the Taiji telescope. Subsequently, we have carried out a detailed stray light analysis of the Taiji Telescope, and have come to the following conclusions:  
1. In the optical system of the Taiji telescope, the third and fourth mirrors were the main scattering sources, accounting for 31.02% and 67.22% of the total scattering energy, respectively. The primary mirror contributed the least to the backscattering energy, accounting for only 0.03%.
2. The optimal combination of the surface roughness was obtained by analyzing the backscattering caused by the surface roughness. The PST was \(3.89\times 10^{-10}\) when the surface roughness of M1, M2, M3, and M4 were 20 A, 4 A, 1 A, and 1 A, respectively.
3. Through the analysis of the backscattering caused by particle contamination, it was obtained that the cleanliness control level of the telescope was required to be better than 300, and the PST of the optical system was \(3.55\times 10^{-12}\) at this condition.
4. Although the primary mirror of the Taiji telescope should be damaged by the impact of micrometeoroids after entering orbit, the variation of the PST of the Taiji telescope can be neglected because the contribution of the primary mirror to the scattered energy was very small.  
In general, the backscattering of the Taiji telescope has a significant impact on the phase noise. The Taiji telescope is required to ensure good environmental cleanliness during installation and storage. For the surface roughness, the M3 and M4 need to be strictly limited. In the future study, we will ultra-smooth the optical surface and measure its BSDF, and finally complete the analysis of scattered light of the Taiji telescope based on the actual measurement data.  
Conceptualization, B.S.; methodology, B.S.; software, X.D.; validation, W.S. and W.T.; formal analysis, Y.D.; investigation, B.S.; resources, B.S.; data curation, X.D.; writing--original draft preparation, B.S.; writing--review and editing, W.S.; visualization, W.S.; supervision, W.S.; project administration, W.T.; funding acquisition, Y.D. All authors have read and agreed to the published version of the manuscript.  
This research was funded by National Key Research and Development Program of China, grant number 2020 YFC2201300.  
The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy.  
The authors declare no conflict of interest.
# Replicas Strategy and Cache Optimization of Video Surveillance Systems Based on Cloud Storage
## 1 Introduction  
With the arrival of the Big Data era, the amount of video data in modern society is growing at an unprecedented speed; especially in the field of video surveillance, there has been an explosion in the total amount of video data [1]. Data has been an essential resource, and how to better manage and use it has become crucial. The scale effect of Big Data brings extraordinary challenges to data storage and data analysis.  
The issue of massive video data processing is a common problem in Big Data technology; especially with the deepening of the construction of the city, video surveillance technology has received more and more attention from the community. It is of great theoretical and practical significance to study how to realize the storage and retrieval of video data effectively. Storage technology [2; 3; 4] is a vital issue in video surveillance systems. The cloud storage of video surveillance is a research hotspot. Researchers have done a lot of work and achieved some results. However, there are still some challenges. The number of replicas of video files in the distributed system is a man-made definition [5; 6]. Hadoop Distributed File System (HDFS) has a default number of copies. If we save the data according to the default number, we need massive storage space. This mechanism can effectively guarantee the security of video data. However, it cannot accurately reflect the security level of the video file in many application environments, and the redundant data always waste storage resource. The deduplication checks (i.e., the corresponding essential message exchange) create a side channel, exposing the privacy of file existence status to the attacker. The random response (RARE) approach achieves stronger privacy. Both deduplication benefit and privacy of RARE can be preserved [7].  
Besides, when users play back video data to track a target's action path, how to predict the target's action path and add the video data to the cache in advance is a significant question.  
For this reason, the purpose of this paper is to optimize replicas strategy and data cache strategy in cloud-based video surveillance systems. Firstly, we propose a dynamic redundant replicas mechanism based on security levels, which dynamically adjusts the number of redundant replicas. Secondly, we design a more realistic cache mechanism according to the position and time correlation of the front camera. The following sections have detailed descriptions of two improvements and validate in the actual applications.  
The rest of this paper is organized as follows: Section 2 describes several studies closely related to our research. Section 3 introduces the architecture of the cloud-based video surveillance system. Sections 4 and 5 describe the dynamic redundant replicas mechanism based on security levels and data caching strategy based on location correlation in details. Experimental verification and analysis can be found in Section 6. Finally, Section 7 concludes this paper and states future research options.
## 3 Results and Discussion
Figure 8: Comparisons of our determined \(b_{ext}\) with AOD (Aerosol Optical Depth) from Aerosol Robotic Network (AERONET) (Seoul-SNU station, 37.458 N, 126.951 E) during the sampling period for a GSD = 1.5 and for (**a**) dg = 0.1 \(\upmu\)m, (**b**) dg = 0.5 \(\upmu\)m, and (**c**) dg = 1.0 \(\upmu\)m.
# Fluctuation-Enhanced Sensing (FES): A Promising Sensing Technique
## 6 Reducing Errors and Enhancing the Sensory Information Channel Capacity
### Temperature Variation Techniques  
Instead of photons, the dormant states can often be activated by proper temperature changes provided that the temperature change required for the given activation energy is feasible. It should also be noted here that Dutta-Horn analysis on some Taguchi sensors showed that if the measured fluctuations were thermally activated, the potential barriers were also strongly temperature dependent [52].
## 4 Study 2: A Case Study
### Methodology
#### 4.1.5 Procedures  
The study took place in Q2 of 2019. At the start of the study, participants were introduced to the cube and explained how to access the narratives. No specific instructions were given other than to freely select the audio narratives in the order they wanted. They were allowed to walk anywhere within the site. Participants were either given a smartphone and noise cancelling earphones, or they used their own devices to access the audio narratives. Since the site was not close to a main road and has generally not many passing visitors during the week, background noise was not considered an issue [43]. During their explorations, participants were shadowed and observed. A map of the test site was used to annotate navigation, touch points, and behavioural insights. Participants decided when they finished by reporting back to the observer. At the end of study, they were invited to answer a short version of the MEC-SPQ (Measurements, Effects, Conditions Spatial Presence Questionnaire) to measure engagement [44]. The MEC-SPQ was designed for immediate assignment after media exposure, and the short version consists of 28 question items representing seven constructs including process  
Figure 2: Each participant used a cube with images and QR codes on the various sides to access the text and audio information for each target. On one side of the cube, questions were shown to trigger visitors thoughts when roaming around.  
factors (attention allocation, spatial situation model, self location, and possible actions), variables referring to states and actions (higher cognitive involvement and suspension of disbelief), and variables addressing enduring personality factors (i.e., domain-specific interest). Each construct contains 4 questions that can be answered on a 5-point Likert scale ranging from 1 (\"I do not agree at all\") to 5 (\"I fully agree\"). Here, a short description of each constructs follows:  
* attention allocation, i.e., to understand which media was more effective in communicating, written text, images, or audio;
* spatial situation model, i.e., to understand the users' ability to describe to what extent it was possible to link the content to their physical surroundings;
* self-location, i.e., to understand how grounded the users felt in relation with the mixed-media environment;
* possible actions, i.e., the sensation of being able to take action in the mediated environment;
* higher cognitive involvement, i.e., to understand how the content activated the thinking of the users;
* suspension of disbelief, i.e., to understand if the users were able to spot errors in the content or were biased toward the user-generated content; and
* domain-specific interest, i.e., to understand how much the users were interested in the topics related to the study.  
The group of participants who had the option to listen to both the curator narrative and the user-curated narrative was asked to comment on and to explain their preferences. Demographics were also collected at the end.
# Estimating Position from Millisecond Samples of GPS Signals (the \"FastFix\" Algorithm)
## 2 Satellite Signal Acquisition
### Relative Fractional Codephase  
The relative fractional codephase, \(\delta_{\phi}^{ij}\) is the difference (modulo \(\tau\)) between the fractional codephases \(\delta_{\phi}^{i}\) and \(\delta_{\phi}^{j}\) from satellite \(i\) and satellite \(j\). From Equation (4),  
\[\delta_{\phi}^{i}\tau-\delta_{\phi}^{j}\tau = (M^{i}-M^{j})\tau+\left(\frac{\Delta_{r}^{i}}{c}-\frac{\Delta_{r }^{j}}{c}\right)\] \[\delta_{\phi}^{i}-\delta_{\phi}^{j} = \left[(M^{i}-M^{j})+\left(\frac{\Delta_{r}^{i}-\Delta_{r}^{j}}{c \tau}\right)\right]\] \[\delta_{\phi}^{i}-\delta_{\phi}^{j} = N^{ij}+\delta_{\phi}^{ij},\]  
where \(N^{ij}=M^{i}-M^{j}\) is the integer part of the expression, and the relative codephase \(\delta_{\phi}^{ij}\) is the fractional part of the expression. For example,  
\[\delta_{\phi}^{ij}(t,\mathbf{r}_{0}) = \text{frac}\left(\frac{\Delta_{r}^{i}-\Delta_{r}^{j}}{c\tau} \right). \tag{5}\]  
This relative fractional-codephase does not depend sensitively on accurate knowledge of the local time offset \(t_{u}\); however, range errors due to incorrect time estimates will have an effect. Errors of 50 km or more will still lead to relatively small changes in \(\delta_{\phi}^{ij}\). At typical satellite velocities of \(\sim\)3 km s\({}^{-1}\), an uncertainty of ten seconds in \(t_{u}\) would lead to a typical \(\delta_{\phi}^{ij}(t,\mathbf{r}_{0})\) uncertainty of approximately 0.1. Contrast this with the codephase \(\delta_{\phi}^{i}\), for which this level of uncertainty would be caused by a \(\sim\)100 \(\upmu\)s uncertainty in \(t_{u}\).
###### Abstract  
Presently, the Earth Observation community is demanding applications that provide low latency and high downlink capabilities. An increase in downlink contacts becomes essential to meet these new requirements. The Federated Satellite Systems concept addresses this demand by promoting satellite collaborations to share unused downlink opportunities. These collaborations are established opportunistically and temporarily, posing multiple technology challenges to be implemented in-orbit. This work contributes to the definition of the Federation Deployment Control Protocol which formalizes a mechanism to fairly establish and manage these collaborations by employing a negotiation process between the satellites. Moreover, this manuscript presents the results of a validation campaign of this protocol with three stratospheric balloons. In summary, more than 27 federations with 63.0% of throughput were established during the field campaign. Some of these federations were used to download data to the ground, and others were established to balance data storage between balloons. These federations allowed also the extension of the coverage of a ground station with a federation that relayed data through a balloon, and the achievement of a hybrid scenario with one balloon forwarding data from a ground device. The results demonstrate that the proposed protocol is functional and ready to be embedded in a CubeSat mission.  
Federated Satellite Systems; satellite networks; Internet of Satellites; Earth Observation; non-terrestrial-network Article  
Towards Federated Satellite Systems and Internet of Satellites: The Federation Deployment Control Protocol  
15 January 2021  
1224 February 2021  
Submitted: 5 March 2021