esa-sceva/satcom-chunk-collection huggingface dataset:
## 3 Results and Discussions
### Thermal Mechanical Properties  
Similar to the PCL-SMPUs, the maximum elongation at break (or the maximum strain) for the PEG-SMPUs varies significantly with \(\gamma\) as shown in Figure 5(a,b). The PCL-SMPUs show high maximum strains at break; it is about 930% for PCL-S1 with 100% MDI, gradually decreasing to about 192% as \(\gamma\) decreases from \(\gamma\) = 1 to 0.325. Compared with those of the PCL-SMPUs, the maximum strains of the PEG-SMPUs are less than half of those of the PCL samples with the same \(\gamma\). It is clear that the PCL-2000 polyol produces more flexible and elastic SMPUs than the PEG-6000 polyol does. These results are consistent with the observations from both the DSC and WAXD measurements, _i.e._, the PEG-SMPUs have high crystallinity and are stiff, and their stiffness increases with the IPDI concentration. Inter-molecular interaction at the soft segment sites is reduced as the molecular weight increases, and this may also be responsible for the early break of the PEG-SMPUs [27; 28]. Furthermore, PEG-6000 has N\({}_{\text{OH}}\) \(\sim\)18, much smaller than that of PCL-2000 (N\({}_{\text{OH}}\)\(\sim\)55), providing much less cross-link sites for reaction with the hard segments. Consequently, the PEG-SMPUs have much fewer cross-links, weaker mechanical strength and lower elongation at break. It is also clear from the results shown in Figure 6(a) that a higher molar ratio of MDI to IPDI is better for synthesizing both the sample series with larger maximum strains, consistent with our previous work [20].  
Figure 5: Stress _vs_. strain for PEG (**a**) and PCL-SMPUs (**b**) series at ambient temperature.  
Figure 6: Summary of elongation at break (**a**) and maximum stress (**b**) for PEG and PCL SMPUs, respectively, at ambient temperature.  
The maximum tensile strength, defined as the stress at which the sample breaks, for both PEG and PCL based SMPUs are summarized in Figure 6(b). The maximum strength of the PEG-SMPUs show a gradual increase with the IPDI content, whereas those of the PCL-SMPUs shows a decrease of the maximum strength with the IPDI content, in agreement with our previous work [20]. This remarkable difference clearly indicates that the chemistry of the polyols plays a vital role in the thermal mechanical behaviour of the SMPUs. This may be due to (a) the resistance of the IPDI to the movement of the soft segment chains, which will enhance the stiffness of the SMPU with a high IPDI concentration [29]; and (b) the high crystallinity of the high molecular weight polyols as discussed above. Stress _vs._ strain behavior for the PCL-SMPUs shows more elastic behavior, _i.e._, the stress rapidly increases with strain initially, and then is followed by a linear increase. Whereas, that of the PEG-series shows a clear plastic behavior, _i.e._, the stress increases with strain initially and then drastically decreases; a typical plastic behavior.
# Evaluation of Eco-Efficiency of Two Alternative Agricultural Biogas Plants
## Materials and Methods
### Levelized Cost of Electricity  
Calculation of costs was performed with the use of the Levelized Cost of Electricity (LCOE) method, taking into account the discount rate at a level of 6% according to EU recommendation [15]:  
\[\sum P_{MWh}*MWh*(1+r)^{-t}=\sum[(Capital_{t}+OM_{t}+F_{t}+C_{t}+D_{t})*(1+r)^{-t}] \tag{1}\]  
\[LCOE=P_{MWh}=\frac{\sum[(Capital+OM_{t}+F_{t}+C_{t}+D_{t})*(1+r)^{-t}]}{\sum MWh* (1+r)^{-t}} \tag{2}\]  
where:  
\(P_{MWh}\)--amount of compensation for electricity production fixed throughout the life cycle (determined level of support);  
_MWh_--quantity of electricity produced in \(t\)-year [MWh]; a fixed value was assumed;  
\((1+r)^{-t}\)--discount rate in \(t\)-year;  
_Capital_--total investment costs in \(t\)-year;  
_OM\({}_{\Gamma}\)_--operating and maintenance costs in \(t\)-year;  
\(F_{\Gamma}\)_--fuel costs in \(t\)-year;  
\(C_{t}\)_--CO\({}_{2}\) emission costs in \(t\)-year;  
\(D_{\Gamma}\)_--costs of plant liquidation and waste utilisation in \(t\)-year.  
The LCOE method was chosen due to the fact that it is most widely used in EU countries using the feed-in tariff system. It allows the comparison of all energy generation costs from various sources, created by various technologies during their entire lifecycle. The normalised LCOE assessment methodology was developed by the U.S. Energy Information Administration (EIA) [16], one of the most important independent American institutions. The distributed cost of energy production represents the minimum price at which the sum of discounted revenues is equal to the sum of discounted costs, taking into account investment costs incurred on the construction, operating and financial costs, and the cost of equity incurred in a given period of installation life cycle. The LCOE method reflects the general technological and financial risk; it represents the real investment cost associated with the production of electricity on regulated monopoly electricity markets with regulated prices [15]. Equation (2) indicates the equality between the present value of the discounted income and the current value of the discounted costs, taking into account investment expenditures [15]. It should be emphasised that it is not the amount of energy produced that is discounted, but the income obtained from the sale of a certain amount of energy during a given year, i.e., the economic value of the energy produced.
## 2 Materials and Methods
### Drought Monitoring Analysis of SIF  
To validate the drought monitoring performances of our downscaled TSIF, we applied it to monitor the Henan drought event of July 2019. We explored the response of _SIF_ and EVI to the drought. We also used SPEI, the anomalies of precipitation, to characterize the spatial and temporal patterns of the drought. Due to the short period of TROPOMI, the anomalies of TSIF could not be calculated. We set 2018 as the reference year and calculated the relative difference defined in Equation (1) to monitor the drought event. The method is similar to that of [PERSON] et al. [14] who used the difference in _SIF_ between two years for drought monitoring. Our method shows the relative changes in _SIF_ between two years that may be caused by drought, which makes every pixel comparable.  
\[\text{Variable}-\text{Diff}= (\text{Variable}_{2019}-\text{Variable}_{2018})/\text{Variable}_{2018} \times 100 \tag{1}\]  
where Variable-Diff could be TSIF-Diff for TSIF, TROPOSIF-Diff for TROPOSIF, USIF-Diff for USIF, or EVI-Diff for EVI. Variable\({}_{2018}\) indicates that the variable is for 2018, while Variable\({}_{2019}\) is for 2019. Negative Variable-Diff means the occurrence of drought and positive Variable-Diff means no drought occurs. Of course, the drought is just relative to the reference year.
# Combined MvdXML and Semantic Technologies for Green Construction Code Checking
## 2 Research Background
### Code-Checking Approaches in Construction Industry  
There are four types of code-checking approaches, i.e., code checking based on existing BIM software, code checking based on object-oriented approach, code checking based on logical rules, and code checking approach based on semantic web. Their characteristics and limitations are summarized in this section.  
The code-checking approach based on existing BIM software and code checking based on an object-oriented approach are usually used for simple quantitative model checking, and they both have less scalability. The code-checking approach based on logical rules and the code-checking approach based on semantic web are both widely used. MvdXML technology is a code-checking approach based on logical rules. [PERSON] et al. compared mvdXML technology and semantic web technology to deal with abstract concepts or physical objects, and pointed out that each method has its pros and cons and can be used according to the requirements of the research project [14]. The mvdXML method is an appropriate choice for simple logical rules. In the implementation of mvdXML method, the BIM Collaboration Format (BCF) is used to report identified issues. BCF is an open standard originally proposed by buildingSMART to enable workflow communication between different applications. Unlike traditional text-based reports, mvdXML method links communication to model view, and it can also be easily implemented by visualization applications. The code-checking approach based on semantic web can perform complicated semantic inferences which cannot be conducted in the mvdXML approach; therefore, it is also widely used.  
Based on the particularity and requirements of green construction code checking, we combined mvdXML technology and semantic web technology to conduct green construction code checking. Therefore, we mainly introduce the latter two approaches here.
## 4 Methods  
### Q Estimation  
#### 4.1.1 Spectral Ratio  
In this study, Q was estimated using a spectral ratio method proposed by [28]. Using this method, a frequency independent quality factor is estimated on the signal recorded by at least two receivers placed on different depths. The quality factor between the two receivers can be estimated using the formula proposed by [29]:  
\[ln\left|\frac{A_{1}(f)}{A_{2}(f)}\right|=const+\pi\frac{\Delta t}{\text{Q}}f \tag{1}\]  
After the transformation, Q can be calculated as:  
\[\text{Q}=\pi\frac{\Delta t}{m} \tag{2}\]  
where \(\Delta t\) is the difference of the time first arrivals of the downgoing P-waves between the shallower referenced receiver and the receiver placed below the referenced one; m is the linear regression coefficient calculated in the defined frequency range on the logarithmic plot of the ratio of spectrums of the analyzed signals (\(A_{1}\) (\(f\)) and \(A_{2}\) (\(f\))). The spectral ratio technique is one of the most popular methods to calculate the Quality factor, hence, here, we only refer to several studies that used this technique [29; 30; 31; 32]. The most crucial element in the Q calculation is source repeatability [33]. Typically, the VSP measurements are performed in a manner to which the source is fired numerous times as the survey is being moved along the borehole. To overcome the problem of non-repeatability of the seismic source and selecting a proper reference receiver, we used the statistical approach, where we selected several shallowest receivers as the reference and performed a spectral ratio measurement between all receivers that were below the reference one. The final Q distribution was calculated as the median value from all iterations and was filtered using a median filter.  
Figure 3: Example of the frequency content of the direct arrival of the downgoing p-wave. Red is the spectrum of the signal recorded at depth 230 m, black is the spectrum of the signal recorded by the receiver at depth 360 m.
# Real-Time, Content-Based Communication Load Reduction in the Internet of Multimedia Things
## 4 Results
### Video Quality Metrics  
Video quality and accuracy of information is measured for all test videos. For the purpose of justifying results in a more elaborative way, two major video quality metrics were used in this study namely, SSIM and PSNR. The results obtained are presented next.
###### Abstract  
In order to describe resistivity variation regularities during the process of damage evolution of loading coal mass more comprehensively and accurately, electrical resistivity and acoustic emission (AE) characteristics of coal mass were tested by 3532-50 LCR tester and _AMS_Y-6 AE data acquisition system under the condition of multi-stage loading, and resistivity variation characteristics were analyzed with stress changing. The damage evolution process of coal mass was studied by the measurement of the AE parameters, and the resistivity curve was obtained in the damage conditions based on the relationship between the AE damage variable and the resistivity. The results show that resistivity and stress curves of coal mass have a good correspondence during the multi-stage loading, and the resistivity shows a trend of fluctuating downward with the increasing of stress. The resistivity increases sharply to the maximum value when the load increases to the ultimate compressive strength of specimens. AE information can reveal effectively damage evolution process of microcracks formation, expansion and fracture in coal mass under external force, and during multi-stage loading, the cumulative AE ringing counts curve of coal mass have three different types of growth trends: stable stage, sudden change stage, gradual increasing stage. Meanwhile, the relationship between resistivity and AE damage variable is established based on the formula of damage variable under uniaxial compression and combined with continuous damage mechanics, and its rationality is verified.  
coal mass; multi-stage loading; electrical resistivity; acoustic emission; damage evolution +
Footnote †: journal: Applied Sciences
## 3 Results and Discussion
### 3.2. Mechanical Analysis  
#### 3.2.1. Tensile Strength of Oriented Specimens  
PA6-cellulose pulp composites with cellulose composition of 5, 10, 15, 20, and 25% were prepared, and shown in Figure 6. These pellets were manufactured into test specimens using injection molding. The samples turned light brown with respect to the increasing order of pulp cellulose composition.  
Figure 5: TGA curve, and DTG for the current cellulose pulp fibers.  
The mean values of tensile strengths of the oriented specimens are shown in the Figure 7a for dry samples and in Figure 7b for 48-h conditioned samples, conditioned at temperature (\(23\pm 2\)\({}^{\circ}\)C) and relative humidity (\(50\pm 5\%\)). The control sample of dry PA6 had a tensile strength of 53.30 MPa. For all formulations, the properties were in accordance to the cellulose fiber orientation inside the composite. It is worth mentioning that 25 wt % of cellulose fiber was the maximum amount of fiber reinforcement affordable for the PA6 matrix. Higher amounts of cellulose fibers were not allowed as the PA6 matrix did not show proper fiber distribution and fiber wrapping along the composite material.  
Parallel oriented specimens (0\({}^{\circ}\)) displayed the best results substantiating the wood pulp fiber composites with high orientation in longitudinal alignment have higher mechanical properties [42]. The tensile strength increased gradually with respect to increase in pulp cellulose composition. The maximum value of 66.17 MPa was obtained for 20% composition followed by 64.76 MPa for 25% composition for dry samples. These tensile strength value corresponds to a 24% higher than the values of the control sample. For 45\({}^{\circ}\) oriented samples, the values of tensile strength values were  
Figure 6: Cellulose pulp composites pellets indicating their respective cellulose composition prepared from Gelimat mixer and later pelletized prior to injection.  
Figure 7: Tensile strength of oriented samples, (a) dry samples and (b) 48-h conditioned samples.  
intermediate between 0\({}^{\circ}\) and 90\({}^{\circ}\) oriented samples with the highest value being 60.44 MPa for dry sample of 25% composition. The 90\({}^{\circ}\) oriented samples exhibited the least values as the elongation took place perpendicular to the fibers alignment, this is because of the anisotropic properties defined by morphology of composites [44]. All the tensile strength values for 48-h conditioned samples showed lower values than the dry ones since the samples absorb moisture during the 48-h conditioning in the climatic chamber and water molecules behave as plasticizer in the course of tensile testing. Here, the maximum tensile strength values were found at 15 wt % cellulose content, with an increment from 48.8 to 59.4 MPa in value with respect to the neat PA6 conditioned. For perpendicular oriented fibers, the strength tends to decrease with the fiber content due to the increase amount of transverse fibers with very low cross section strength that tends to behave as defects along the measurement direction.
# Name-Based Security for Information-Centric Networking Architectures
## 5 Implementation and Evaluation
### DID Performance Evaluation
#### 5.1.2 DID Cryptographic Operations Overhead  
In our DID registry implementation, only DID document owners are allowed to modify a DID document. In order to achieve this, a DID registry must authenticate a users based on the key included in the DID document.  
W3C's (draft) DID specification defines that the keys used for user authentication must be compliant with the authentication cryptographic suites included in the \"Linked Data Cryptographic Suite Registry\" [22]. Currently, this registry includes four suites, and for our implementation, we have selected the \"Ed25519 Signature 2018\" suite [23]. This suite uses keys derived from the curve25519 elliptic curve and defines that authentication should be implemented using Ed25519 signatures. The size of the public key is 32 bytes and the size of a signature is 64 bytes.  
User authentication is implemented using a simple challenge-response protocol, where the registry generates a random number and the user responds with the digital signature of that number (All messages are exchanged over TLS hence man-in-the-middle attacks are prevented).  
DIDs require the following cryptographic operations: key-pair generation, signature creation, and signature verification. We have implemented all these cryptographic using the TweetNaCl cryptographic library [24]. Table 2 measures the execution speed of each operation in a high-end PC (3.4 GHz intel-i7 CPU, 16 GB of RAM, running Ubuntu 16.04 Server ), a first-generation Raspberry Pi (700 MHz BCM2835 CPU, 512 MB of RAM, running Raspbian GNU/Linux 9 distribution), and the Safari browser of an iPhone 7s (Running iOS 12.3.1) (For this measurement we used the JavaScript port of the library available here: [[https://tweetnacl.js.org](https://tweetnacl.js.org)]([https://tweetnacl.js.org](https://tweetnacl.js.org))).  
As it can be observed, all cryptographic operations are executed very fast even by the constrained devices.
# Systematic Mapping Study on Remote Sensing in Agriculture
## 2 Research Methodology
### Formulation of the Mapping Questions  
After analyzing the most interesting aspects to extract from the papers, a total of eight mapping questions (MQs) were defined. These questions help to perform the subsequent search and analysis processes. The first four questions (MQ1-4) extract general information about the publication channels, the frequency of the approaches, the research types and the empirical validation of the RSA studies. The rest of the questions (MQ5-8) are related to more specific aspects of RSA, such as the techniques used, the devices for image capturing, the problems addressed, and the type of spectral information considered. All these MQs were formulated to cover the key factors that comprise the field of RSA. Table 1 presents these MQs with the rationale that motivate their importance.  
\begin{table}
\begin{tabular}{l l l} \hline \hline
**ID** & **Mapping Question** & **Rationale** \\ \hline \multirow{3}{*}{MQ1} & What publication channels are the main targets for & Identifying where RSA research can be \\  & RSA? & found, and the most adequate publication \\  & & channels for future works \\ \multirow{3}{*}{MQ2} & How has the frequency of approaches related to & Identifying publication trends over time \\  & RSA changed over time? & related to RSA \\ \multirow{3}{*}{MQ3} & What are the main research types of RSA studies? & Exploring different types of research \\  & & existing in the literature about RSA \\ \multirow{3}{*}{MQ4} & \multirow{3}{*}{Are RSA studies empirically validated?} & Discovering if research works on RSA has \\  & & been validated with empirical methods \\ \multirow{3}{*}{MQ5} & \multirow{3}{*}{What types of techniques were reported in RSA } & Detecting the most important types of \\  & & computer vision and machine learning \\ \multirow{3}{*}{MQ6} & \multirow{3}{*}{What are the platforms used to capture the images} & techniques reported in the existing RSA \\  & & literature \\ \multirow{3}{*}{MQ7} & \multirow{3}{*}{What are the research topics addressed by RSA?} & Exposing the main types of devices \\  & & employed to obtain the images in RSA \\ \multirow{3}{*}{MQ8} & \multirow{3}{*}{What are the different types of spectral} & Studying what are the most prominent \\  & & topics currently tackled in RSA research \\ \multirow{3}{*}{MQ9} & \multirow{3}{*}{What are the different types of spectral} & Analyzing what types of images are \\  & information used? & the most frequently used in RSA research \\ \hline \hline \end{tabular}
\end{table}
Table 1: Mapping questions defined in the present review.
# HVdc Circuit Breakers: Prospects and Challenges
## 7 Available HVdc Breakers from Tech Giants
### Alstom's Hybrid HVdc Breaker  
A hybrid dc breaker from Alstom Grid is a combination of a semiconductor breaker and a mechanical HVdc switch. Figure 10 depicts the structure of this circuit breaker [102]. Besides mechanical contact, the core branch also includes a low voltage switch. Alstom dc breaker has two extra branches: (i) energy absorption and (ii) commutation branch (or arming branch). The control strategy for fault current interruption of this kind of hybrid breaker is shown in Figure 11.  
Figure 10: Hybrid HVdc breaker, proposed by Alstom grid [102].  
Figure 9: Control strategy for fault current interruption of hybrid HVdc Breaker, proposed by ABB [137].  
During steady-state and normal operation, the current will pass through the main branch. The low voltage switch produces low power losses and the contact voltage is also zero. Several components are connected in parallel for current rating and series for voltage rating. In the event of a fault, a huge amount of fault current will flow through the main branch. As soon as the fault is detected, the commutation branch will be closed, and the low voltage switch will be opened. Most of the fault current will commutate through the commutation branch at this moment. The mechanical switch may open without any arcing across its terminals until the fault current flow through the main branch is mitigated to nearly zero. When the commutation branch is turned off, the fault current is forced to pass in the energy absorption unit. The voltage developed across the energy absorption unit must be larger than the source voltage to decrease the fault current and reduce the breakdown voltage of the mechanical switch. The total time to current extinction and the rate of fault current is determined by the difference of voltage developed across the energy absorption unit and the source in an inductive circuit [102].