esa-sceva/satcom-chunk-collection huggingface dataset:
# PriSign, A Privacy-Preserving Single Sign-On System for Cloud Environments
## 7 Performance Analysis
### Theoretical Analysis  
In Tables 4 and 5, the proposed PriSign system is compared with state-of-the-art ASSO systems [8; 9] in terms of computation and storage overheads. Let \(|\mathbb{G}_{1}|\), \(|\mathbb{G}_{2}|\),\(|\mathbb{G}_{\mathbb{T}}|\) and \(|\mathbb{Z}_{p}|\) be the element sizes in group \(\mathbb{G}_{1}\), \(\mathbb{G}_{2}\), \(\mathbb{G}_{\mathbb{T}}\) and \(\mathbb{Z}_{p}\), respectively; here, \(t_{\varepsilon_{1}}\), \(t_{\varepsilon_{2}}\), \(t_{\varepsilon_{T}}\) and \(t_{p}\) represent the time cost for the exponential in group \(\mathbb{G}_{1}\), \(\mathbb{G}_{2}\), \(\mathbb{G}_{\mathbb{T}}\) and the pairing computations, respectively.  
Figure 12: Verify algorithm.  
Table 4 presents the storage cost of the algorithms in our PriSign system, including Setup, IssuerReg.1, IssuerReg.CA, IssPolKey, AggrPolKey, UserReg.U, UserReg.CA, ObtTkt.U, ObtTkt.1, SignOn, and Verify. Because the systems in [8; 9] do not support policy issuing with thresholds, the performance comparison does not include IssPolKey and AggrPolKey. As shown in Table 4, even though our scheme supports token-hiding and designating verifiers, it is nonetheless able to achieve constant complexity \(O(1)\) of service access (SignOn) and verification (Verify) under the selected parameter \(k\). In addition, it takes only a single exponentiation operation in \(\mathbb{G}_{2}\) for a policymaker to generate a policy key for a verifier (IssPolKey); while the computational complexity of the aggregate key is linear (\(O(t)\)) to the threshold value (AggrPolKey), \(t\) is fortunately small in actual deployments. Because the systems in [8; 9] do not support attribute-based fine-grained access control, the computational cost of obtaining tickets and sign-on in their systems is independent of \(q\). Obviously, when \(q=0\), \(J=1\), the computational cost of our system is close to that of the systems in [8; 9].  
Table 5 presents the computation cost of the algorithms in our PriSign system, including \(msk\), \(mpk\), \(isk\), \(ipk\), \(iced\), \(usk\), \(upk\), \(ucred\), \(pst\), \(tkt\), and \(tok\). As shown in Table 5, the user credential \(ucred\), ticket seller credential \(iced\), ticket \(tkt\), and access token \(tok\) all have constant size in the PriSign scheme. The storage overhead primarily consists of the mast public key \(mpk\), for which it is only necessary to store one copy for each user. In addition, when \(q=0\), \(J=1\) the storage cost of our system is close to that of the systems in [8; 9], even with our system's has additional support for token-hiding and policy issuing with thresholds.
# A DFT-Based Running Time Prediction Algorithm for Web Queries
## 5 Experimental Evaluation
### An Application Case for Query Running Time Prediction
#### 5.5.1 Accuracy Evaluation of the DFT-Based Algorithm under Multi-Thread Query Processing
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  & \multicolumn{8}{c}{**5 Neurons in the Hidden Layer**} \\ \hline
**Threads** & \multicolumn{2}{c}{**Real**} & \multicolumn{2}{c}{**Baseline**} & \multicolumn{2}{c}{**DFT-Based**} & \\
**QRT** & \multicolumn{2}{c}{_max_} & \multicolumn{2}{c}{**QRT**} & \multicolumn{2}{c}{_max_} & \multicolumn{2}{c}{**AAE**} & \multicolumn{2}{c}{_max_} & \multicolumn{2}{c}{**QRT**} & \multicolumn{2}{c}{_max_} & \multicolumn{2}{c}{**AAE**} & \multicolumn{2}{c}{_max_} \\ \hline
1T-L/S & 0.133 & 1.062 & 0.133 & 0.839 & **0.025** & 0.376 & 0.134 & 0.909 & **0.025** & **0.370** \\ \hline
2T-L & 0.091 & 0.668 & 0.091 & 0.506 & 0.016 & 0.283 & 0.091 & 0.492 & **0.014** & **0.256** \\
2T-S & 0.075 & 0.586 & 0.076 & 0.422 & 0.015 & 0.489 & 0.075 & 0.364 & **0.014** & **0.222** \\ \hline
4T-L & 0.062 & 0.424 & 0.062 & 0.356 & 0.009 & 0.191 & 0.061 & 0.353 & **0.008** & **0.148** \\
4T-S & 0.043 & 0.323 & 0.043 & 0.263 & **0.008** & 0.305 & 0.043 & 0.195 & **0.008** & **0.132** \\ \hline
8T-L & 0.057 & 0.406 & 0.056 & 0.403 & 0.007 & 0.204 & 0.056 & 0.296 & **0.006** & **0.196** \\
8T-S & 0.036 & 0.256 & 0.035 & 0.240 & **0.006** & 0.104 & 0.034 & 0.206 & **0.006** & **0.093** \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Results obtained under ClueWeb09-BM25 with the actual execution of the multi-threaded query solution algorithms LBM-WAND (L) and SBM-WAND (S), and the respective query running time predictions delivered by the proposed and baseline algorithms. On the other hand, as we increase the number of threads the Pearson correlation reported by both algorithms is slightly reduced. However, the lost in the correlation is very small, less than 5%.
# Global Power Dynamics in the Contemporary Space System
## 1 Introduction
If such a redistribution is occurring, what is the nature of the changes in the balance of power among the major space actors, and what new space power structure is emerging as a result of these changes? The primary objective of this research study is to address the following three significant systemic changes in the study of the space system: (i) to identify the main space powers in the current international system and explain how they are developing space capabilities; (ii) to describe new dynamics and the redistribution of power within the 21 st century space system; and (iii) to identify the new characteristics and trends of the new structure of power in the space system. The central hypothesis of this research work is that the space system is undergoing an intersystem transition from a unipolar, U.S.-dominant, post-Cold War space system to a new and more complex structure that includes new space powers and a redistribution and rebalancing of power dynamics. The unipolar structure that prevailed in the post-Cold War era has been replaced by a new space system, in which emerging space powers exhibit global ambitions and a willingness to compete with and challenge the United States' dominance. Despite its status as the preeminent space power, the United States has confronted the emergence of new competitors, including China, Japan, and India, in recent years [21]. Additionally, the space landscape has witnessed a proliferation of new coalitions and alliances, including the Artemis Accords, the International Lunar Research Station Cooperation Organization, and numerous regional processes. These shifts in the number of space actors, power dynamics, and the structure of the space system necessitate novel scientific approaches. This research posits the utilization of systems science as a means to enhance our comprehension of the rebalancing of power in the space system in recent decades. The systems approach provides a useful analytical framework to study the intersystem transition that the space system is currently experiencing. The result is a comprehensive study of the major space actors within the 21 st century space system, including an identification of the major and new space powers, as well as the analysis of the redistribution of power among them. The paper is structured as follows: Section 2 describes the systems approach used in this research. Section 3 explains the intersystem transition in the new space system, centering on the evolution from the 20 th century space system to a new space age in the 21 st century. Section 4 examines the relevance and variety of the current space powers, providing a detailed analysis of the major space powers, including the United States, China, Russia, India, the EU, and Japan. Section 5 discusses global space dynamics and the new distribution and polarization of powers in outer space. Section 6 describes the new structure and balance of power of the space system. Finally, Section 7 summarizes the main findings, scientific and academic discussions, and conclusions.
# Longitudinal Structure in the Altitude of the Sporadic E Observed by COSMIC in Low-Latitudes
## 4 Discussion
Additionally, the chemical process of the metal ions, together with the meteoric ablation and the molecular ions (e.g., NO+ and O\({}_{2}\)+), which will control the density of the metal ions [54], may also have an influence on the formation and the variation of the WN4 structure. These factors will be studied in the future through numerical simulation analysis. It has been reported in some papers that the Es layers do not always occur at the wind shear convergence null [55,56]. [PERSON] et al. [57] showed that Es layers could also be formed by homogeneous horizontal winds (with no vertical shear). This process is determined by the horizontal wind direction and velocity, geomagnetic field, and ion-neutral  
Figure 9: The distributions of the amplitudes for the DE3 tide in the zonal wind during (**a**) March, (**b**) June, (**c**) September, and (**d**) December. collision frequency and its vertical changes, which can be easily understood according to Equation (1) if we set \(\frac{d\Omega}{dz}=\frac{dV}{dz}=0\). However, this process will not influence the results of climatology in this study. The altitude of the Es layers is treated as a combination of different wave components. The WN4 structure is not the real altitude for Es layers, but is actually the variation of the Es height. Therefore, the dominant role of the DE3 tide is acceptable for the formation of the WN4 structure even though some of Es layers are not formed at the wind shear convergence null. The WN4 structure is also reported in the occurrence rate of the Es layer by [PERSON] et al. (2019). The structure presented the similar seasonal and latitudinal variations in that work. The WN4 for the occurrence rate in that work aligned with the geomagnetic latitude, while this feature is not evident in this work. This implies that the geomagnetic field has a greater impact on the Es occurrence rate than the Es height. Similarly, the connection was also found between the WN4 of the occurrence rate and the DE3 tide in the zonal wind. However, the process in which the DE3 tide imposes its effect is not the same. The zonal propagation of the DE3 tide is enough for the interpretation of the WN4 in the Es occurrence rate, while the vertical propagation should also be considered when it comes to the WN4 in the Es altitude. This work provides more proof for the correlation between the DE3 tide and the Es layer and demonstrates more comprehensively the effect of the DE3 tide on the Es layer.
## Correlation between Earthqu and AE Monitoring of Historical Buildings in Seismic Areas +  
Footnote †: footnotemark:  
**[PERSON] *, [PERSON], [PERSON], [PERSON] and [PERSON]**  
Department of Structural, Geotechnical and Building Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy; E-Mails: [EMAIL_ADDRESS] (P.C.); [PERSON](G.N.); [EMAIL_ADDRESS] (S.I.); [PERSON].C.)  
This paper is an extended version of paper published in the 6 th International Conference on Emerging Technologies in Non-destructive Testing (ETNDT6), Brussels, Belgium, 27-29 May 2015.  
* Author to whom correspondence should be addressed; E-Mail: [EMAIL_ADDRESS]; Tel.: +39-011-090-4871; Fax: +39-011-090-4899.  
Academic Editors: [PERSON] and [PERSON]  
_Received: 5 November 2015 / Accepted: 26 November 2015 / Published: 8 December 2015_  
**Abstract:** In this contribution a new method for evaluating seismic risk in regional areas based on the acoustic emission (AE) technique is proposed. Most earthquakes have precursors, _i.e._, phenomena of changes in the Earth's physical-chemical properties that take place prior to an earthquake. Acoustic emissions in materials and earthquakes in the Earth's crust, despite the fact that they take place on very different scales, are very similar phenomena; both are caused by a release of elastic energy from a source located in a medium. For the AE monitoring, two important constructions of Italian cultural heritage are considered: the chapel of the \"Sacred Mountain of Varallo\" and the \"Asinelli Tower\" of Bologna. They were monitored during earthquake sequences in their relative areas. By using the Grassberger-Procaccia algorithm, a statistical method of analysis was developed that detects AEs as earthquake precursors or aftershocks. Under certain conditions it was observed that AEs precede earthquakes. These considerations reinforce the idea that the AE monitoring can be considered an effective tool for earthquake risk evaluation.  
**Keywords:** acoustic emission; structural monitoring; cultural heritage; earthquakes; seismic precursors
# Topic-Specific Emotion Mining Model for Online Comments
## 3 Proposed Model
### Topic-Specific Emotion Mining Model
The generative process of TSEM is described as follows: \begin{table}
\begin{tabular}{c c} \hline \hline
**Notation** & **Description** \\ \hline T & Number of time-spans, e.g., quarter, in this paper \\ D & Number of comment documents \\ N & Number of words \\ E & Number of emotions \\ V & Size of vocabulary \\ \(\alpha\) & A K-dimensional dirichlet prior vector for \(\theta\) \\ \(\beta\) & A V-dimensional dirichlet prior vector for \(\varphi\) \\ \(\gamma\) & A E-dimensional dirichlet prior vector for \(\Pi\) \\ \(\theta_{t}\) & A K-dimensional topic distribution of \(t\)th time-span \\ \(\varphi_{lk}\) & A V-dimensional word pair distribution of the \(k\)th topic for \(t\)th sentiment \\ \(\Pi_{kk}\) & A E-dimensional sentiment distribution of the \(k\)th topic for \(t\)th time-span \\ \(t_{d}\) & The time tag of the \(d\)th document \\ \(z_{dt}\) & A topic assignment of the \(n\)th word in the \(d\)th document \\ \(s_{dt}\) & A sentiment assignment of the \(n\)th word in the \(d\)th document \\ \(wp_{dtn}\) & The observed \(n\)th aspect-opinion word pair in the \(d\)th document \\ \(s_{-i}\) & A vector of sentiment assignment for all word pairs except the \(i\)th word pair \\ \(z_{-i}\) & A vector of topic assignment for all words except the \(i\)th word pair \\ \(t_{-i}\) & A vector of observed time-spans for all words except the \(i\)th word pair \\ \(wp_{-i}\) & A vector of observed word pairs except the \(i\)th word pair \\ \(N_{ke}\) & The number of the \(v\)th unique words that are assigned to eth sentiment and the \(k\)th topic \\ \(N_{ke}\) & The number of words that are assigned to eth sentiment and the \(k\)th topic, within \(t\)th time-span \\ \(N_{ik}\) & The number of words that are assigned to \(k\)th topic, within \(t\)th time-span \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Description of notation used in this paper. Figure 4: The graphical model of the Topic-Specific Emotion Mining (TSEM) model: unlike existing emotion topic models, emotion relies on topic rather than the opposite, and observable data ‘timestamps’ are added in our model. 1. Draw topic distribution for each time span: \(\theta_{t}\)-Dirichlet (\(\alpha\));
2. Draw sentiment distribution for each pair of topic and time-span: \(\Pi_{tk}\)-Dirichlet (\(\gamma\));
3. Draw aspect-opinion pair distribution for each pair of sentiment and topic: \(\varphi_{ke}\)-Dirichlet (\(\beta\));
4. For each comment document \(d\): 1. Choose a topic z\(\sim\)multinomial (\(\theta_{td}\)); 2. Choose a sentiment e\(\sim\)multinomial (\(\Pi_{tk}\)); 3. Generate an aspect-opinion pair \(wp\)-multinomial (\(\varphi_{ke}\)). After generating the comment text set through the above steps, the parameters \(\theta\), \(\Pi\), and \(\varphi\) are used to analyze emotions of the review texts.
## 2 Main Components of the OxPhos Pathway in _M. tb_
### Menaquinone (MK) Biosynthesis  
As the sole lipoquinone in mycobacteria, MK has a central and essential role in OxPhos [44; 45]. Its biosynthetic pathway is a highly attractive drug target space as it is absent in humans, and has been demonstrated to be critical for maintaining mycobacterial survival under aerobic and anaerobic conditions [46]. In _M. tb_, the biosynthesis of MK mirrors that of _Escherichia coli_, in which the pathway has been better characterised [45]. Eight enzymes (MenF, MenD, MenH, MenC, MenE, MenB, MenA and MenG) are involved in the pathway, with MenF catalysing the first committed step of the conversion of chorismate [14]. Not all of the genes encoding for the MK synthesis pathway seem to be essential. Through initial transposon studies and confirmation by high-resolution phenotypic profiling experiments, most MK biosynthesis enzymes have been reported to be essential via transposon mutagenesis in H37 Rv for _M. tb_ growth, except for MenF, whose deletion resulted in a growth defect in _M. tb_[31; 32; 33].  
Small molecules inhibiting MenD, MenE, MenB, MenA and MenG, and have been reported [47; 48; 49; 50; 51]. MenD is a thiamine diphosphate-dependent enzyme which catalyses the second step of MK biosynthesis. It uses 2-oxoglutate and isochorismate for the synthesis of 2-Succinyl-5-enolpyruvateyl-6-hydroxy-3-cyclohexene-1-carboxylate (SEPHCHC). MenE encodes for an o-succinylbenzene-CoA ligase that converts o-succinylbenzene (OSB) to OSB-CoA, and is the fifth step of MK biosynthesis in _M. tb_. It is responsible for the addition of a CoA group via an OSB-AMP intermediate [50]. MenB encodes for a 1_A_-dihydroxy-2-naphthoyl-CoA (DHINA-CoA) synthase that catalyses the formation of DHINA-CoA from o-succinylbenzene-CoA and is the sixth step of the MK biosynthesis [52]. MenA encodes for a DHINA-octaphenyltransferase, which is involved in the seventh step of the MK biosynthesis. It catalyses the conversion of 1_A_-dihydroxy-2-naphthoate (DHNA) to demethyllmenquinone (DMK), and uses a variety of allylic isoprenyl diphosphates as substrates, requiring at least three isoprene units [46; 49]. Bacterial MenA was reported to be homologous to the eukaryotic UbiA [53]. Additionally known as UbiE, MenG (rv0558) catalyses the methylation of DMK-9 using S-adenosylmethionine to form MK [54]. This reaction is the last step of MK biosynthesis in _M. tb_. That these enzymes of the MK biosynthesis pathway can be pharmacologically inhibited demonstrate their essentiality and highlight their potential as drug targets.
# Research Progress in the Flight Characteristics of Flyers Driven by Different Technologies
## 3 Research Progress in Flyer Velocity
### Factors Affecting Flyer Velocity
#### 3.2.5 Laser-Driven Flyer  
The main parameters of the laser include wavelength, pulse width, the diameter of the focused spot, and laser power density. There is a noticeable shortage in wavelength [73] and pulse width [74] studies. Other parameters are essentially the distribution of laser energy in time and space. [PERSON] et al. put forward that \"the maximum attainable flyer speed with the larger laser varied from glass substrate to substrate\" [75]. However, there is currently no convincing explanation for this phenomenon.  
The parameters of the metal film and transparent substrate cannot be ignored. In terms of metal film materials, it is generally believed that a flyer with a lower thickness, lower density, and smaller diameter has a faster speed under the condition without affecting the integrity and flatness of the flyer; this has been verified both experimentally and theoretically [76]. The metal film used to launch high-speed flyers requires high density, good thickness uniformity, and high adhesion between the film and the substrate. The flyer target prepared by magnetron sputtering and ion beam sputtering has better quality than electron beam evaporation and field-assisted thermal diffusion. The experimental results show that the flyer target prepared by magnetron sputtering and ion beam sputtering can obtain higher flyer speeds [77]. Moreover, the amount of laser energy allowed to penetrate the transparent substrate is limited. The substrate material may be damaged if the laser energy is too large, thus leading to a reduction in driving capacity. The thickness and strength of the substrate material directly affect the plasma confinement and the shock wave loss, which clearly limits the flyer speed. However, there are few literature reports on the effect of substrate materials on flyer speed [78].  
The optimal constraint and shear effect of the barrel will be formed when its diameter is basically the same as that of the ablation hole produced by the laser. Therefore, the effect of the barrel diameter on the flyer velocity is inconspicuous [79]. Furthermore, the flyer velocity evidently decreases with the increase in the barrel length. Some studies suggest that the shock wave generated at the front of the flyer due to the presence of air will absorb the flyer's energy, thus causing a drop in the flyer speed [80].  
In summary, research on the laws of various factors affecting laser-driven single-layer flyers has achieved certain results, but many of their aspects remain ambiguous or contentious, necessitating more study in both theoretical models and experimental designs. The main factors affecting the flyer speed are summarized in Table 3.
# GPS/BDS RTK Positioning Based on Equivalence Principle Using Multiple Reference Stations
## 4 Discussion  
The results of Section 3 indicate that the reference coordinates of rover receiver (TBR9) are calculated by Waypoint IE software 8.60 for a forward-reverse model with three reference receivers. However, the forward Kalman filter is applied to obtain the positioning results in MBRTK algorithm. The differences of model in the data processing would lead to a systematic positioning error, as shown in Table 6.  
In addition, the positioning results of the forward-reverse model of IE software 8.60 still have the positioning error compared to the true position of rover receiver. Thus, to study the above differences, three additional schemes with different single reference receiver are conducted using the forward-reverse model by IE software 8.60. The statistics are listed in Table 7.  
As can be seen, both the RMS and STD values of SDWA-TBR9 for IE software 8.60 can achieve the mm level and the positioning results are approximately equal to the reference coordinates of rover  
\begin{table}
\begin{tabular}{l c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Schemes**} & \multirow{2}{*}{**Model**} & \multicolumn{3}{c}{**RMS/cm**} & \multicolumn{3}{c}{**Mean/cm**} & \multicolumn{3}{c}{**Number of**} & \multicolumn{1}{c}{**Number of**} \\ \cline{3-10}  & & **N** & **E** & **U** & **N** & **E** & **U** & **Epochs** & **Success** & **Success Rate** \\ \hline IE:SDWA-TBR9 & SBRTK & 0.5 & 0.8 & 0.8 & 0.0 & \(-\)0.1 & 0.1 & 4621 & 4027 & 91.0\% \\ IE:SDWB-TBR9 & SBRTK & 2.7 & 3.6 & 4.2 & 2.1 & 1.6 & \(-\)2.8 & 4621 & 3588 & 77.6\% \\ IE:SOTH-TBR9 & SBRTK & 1.6 & 3.0 & 3.1 & 1.6 & 2.2 & \(-\)2.3 & 4621 & 4106 & 88.9\% \\ MBRTK:Five & MBRTK & 3.0 & 1.5 & 4.6 & \(-\)2.7 & \(-\)0.6 & \(-\)2.5 & 4621 & 4363 & 94.4\% \\ MBRTK:Six & MBRTK & 3.0 & 1.5 & 4.5 & \(-\)2.7 & \(-\)0.5 & \(-\)2.3 & 4621 & 4471 & 96.8\% \\ \hline \hline \end{tabular}
\end{table}
Table 7: Statistics of IE and MBRTK for kinematic experiment.  
Figure 13: L1/B1 carrier residuals for four schemes with different reference receivers.  
receiver by IE software 8.60. However, for the RMS and STD values of SDWB-TBR9 and SOTH-TBR9 using IE software 8.60, there is an obvious systematic error with cm level. That is to say, the reference coordinates by IE software 8.60 with three reference receivers are probably weighted average values based on the positioning results of SDWA-TBR9, SDWB-TBR9, and SOTH-TBR9, and the weight of SDWA-TBR9 is largest among the three single baselines. In other words, the reference coordinates of TBR9 are only relatively precise, but not absolutely accurate. It is worth noting that although the scheme-five and scheme-six still have a systematic error with cm level, the model of MBRTK is rigorous and reliable, which also have a higher success rate than those of three additional schemes by IE software 8.60.