esa-sceva/satcom-chunk-collection huggingface dataset:
# Design, Experiment, and Improvement of a Quasi-Zero-Stiffness Vibration Isolation System
###### Abstract  
This paper proposes a new kind of quasi-zero-stiffness (QZS) isolation system that has the property of low-dynamic but high-static stiffness. The negative stiffness was produced using two magnetic rings, the magnetization of which is axial. First, the force-displacement characteristic of the two coupled magnetic rings was developed and the relationship between the parameters of the magnetic rings and the stiffness of the system was investigated. Then, the dynamic response of the QZS was analyzed. The force transmissibility of the system was calculated and the effects of the damping ratio and excitation amplitude on the isolation performance were investigated. The prototype of the QZS system was developed to verify the isolation effects of the system based on a comparison with a linear vibration isolation platform. Lastly, the improvement of the QZS system was conducted based on changing the heights of the ring magnets and designing a proper non-linear spring. The analysis shows the QZS system after improvement shows better isolation effects than that of the non-improved system.  
Keywords: vibration isolation; quasi-zero-stiffness; magnetic rings spring; transmissibility; improvement of the load capacity +
Footnote †: journal: Applied Sciences
## 4 Numerical Analysis and Discussion
### Sensitivity Analysis  
Sensitivity is often used to evaluate the change of performance caused by a unit variable increment. The variable effects in Section 4.1 on the objective function can be quantified by the sensitivity. The sensitivity analysis of the lockable maximum load of the closing spring \(F_{\rm ml}\) and the permissible stroke of the locking tab [\(L\)] is carried out in this section. Figures 12 and 13 show the sensitivities of \(F_{\rm ml}\) and [\(L\)] with regard to the change rate of variables in the design space, respectively, with a sampling interval of 0.01% of the full range.  
Figure 11: The permissible stroke of the locking tab with (**a**) the effects of \(r_{1}\) and \(r_{3}\); (**b**) the effects of \(r_{2}\) and \(r_{3}\); (**c**) the effects of \(l\) and \(\alpha\).  
As shown in Figure 12, the absolute value of the sensitivities of \(F_{\rm ml}\) increases with the increase in \(r_{2}\), and decreases with the increase in \(l\), \(\alpha\) and \(r_{3}\). When the change rate ranges from 0% to 54.65%, \(l\) is the most sensitive variable and after that \(\alpha,r_{2},r_{3}\); when the change rate ranges from 54.65% to 90.48%, \(l\) is still the most sensitive one and after that \(r_{2}\), \(\alpha,r_{3}\); when the change rate ranges from 90.48% to 100%, the most sensitive variable is \(r_{2}\) and after that \(l\), \(\alpha,r_{3}\). The average variable sensitivities of \(F_{\rm ml}\) are listed in Table 4. In the design space, the most sensitive variable of \(F_{\rm ml}\) is \(l\) and after that \(\alpha,r_{2}\) and \(r_{3}\).  
Figure 12: The absolute value of the sensitivities of \(F_{\rm ml}\) with regard to the change rate of variables in the design space.  
Figure 13: The absolute value of the sensitivities of \([L]\) with regard to the change rate of variables in the design space.  
As shown in Figure 13, the absolute value of the sensitivities of \([L]\) increases with the increase in \(r_{3}\), and decreases with the increase in \(r_{2}\)\(l\), and \(\alpha\); the sensitivity of \([L]\) to \(r_{1}\) remains on the lowest level in the full range; \(\alpha\) is the most sensitive variable in the full range and after that \(l\); when the change rate ranges from 0% to 30.63%, \(r_{2}\) is the third most sensitive variable and \(r_{3}\) is the fourth. The average variable sensitivities of \([L]\) are listed in Table 5. In the design space, the most sensitive variable of \([L]\) is \(\alpha\) and after that \(l\), \(r_{3}\), \(r_{2}\) and \(r_{1}\).
# Predicting Decompensation Risk in Intensive Care Unit Patients Using Machine Learning
## 3 Results
### Model Performance  
Table 3 displays model performance results measured on the test set after calculating the optimal ROC's threshold. It can be seen that RF and CNN-LSTM yielded the best performance among the baseline ML and DL models, respectively. It is worth noting that the baseline ML and DL models are not directly comparable due to differences in the modelling tasks. The best set of hyperparameters for SVM and RF are shown in Table 4.  
Figure 2 shows the optimised LSTM model after hyperparameter tuning. The optimal architecture consisted of two LSTM layers of 64 units each followed by a hidden dense layer of 100 and an output dense layer of 24 units, one for each hour. ReLU and sigmoid activation functions were used in the hidden and output dense layers, respectively. A dropout layer with a drop rate of 0.5 was added after the hidden dense layer.  
\begin{table}
\begin{tabular}{l r r r r} \hline \hline
**Variable** & **Statistics** & **Min, Max** & **\% Missing Values** & **Imputed Value** \\ \hline Age [years] & 67 [55; 77] & 18, 89 & 0 & - \\ Height [cm] & 170 [162.8, 177.9] & 53.2, 231.1 & 55.23 & 170 \\ Weight [kg] & 80.4 [67.6, 96.5] & 32.5, 296.8 & 2.17 & 81 \\ Temperature [\({}^{\circ}\)C] & 36.8 [36.6, 37.2] & 23.1, 43.1 & 0.2 & 36.6 \\ Heart Rate [beats per min] & 84.8 [73; 97] & 15, 295 & 0.001 & 86 \\ Respiratory Rate [breaths per min] & 19.5 [16; 23.5] & 53, 280 & 0.02 & 19 \\ Fraction Inspired Oxygen [\%] & 40 [40; 50] & 20, 100 & 24.44 & 0.21 \\ Oxygen Saturation [\%] & 97 [95; 99] & 42, 100 & 0.004 & - \\ GCS Eye Response & 4 [3; 4] & 1, 4 & 0.02 & 4 \\ GCS Motor Response & 6 [5; 6] & 1, 6 & 0.02 & 6 \\ GCS Verbal Response & 4 [1; 5] & 1, 5 & 0.02 & 5 \\ GCS Total Response & 14 [10; 15] & 3, 15 & 0.02 & 15 \\ Glucose [mg/dL] & 128 [107; 159] & 33, 1884 & 0.1 & 128 \\ Haemoglobin [g/dL] & 9.7 [8.5, 11.2] & 4.8, 21.1 & 0.20 & - \\ Platelet count [k/uL] & 190 [128; 270] & 54, 1475 & 0.19 & - \\ Diastolic Blood Pressure [mmHg] & 61 [53; 72] & 34, 338 & 0.01 & 59 \\ Mean Blood Pressure [mmHg] & 77 [68.0, 88] & 14, 330 & 0.01 & 77 \\ Systolic Blood Pressure [mmHg] & 118 [104.5, 134] & 46, 365 & 0.01 & 118 \\ Blood pH Level & 7.41 [7.36, 7.45] & 6.68, 7.93 & 27.54 & 7.4 \\ Capillary Refill [yes] & 4.26\% & 0, 1 & 6.95 & 0 \\ Prothrombin Time [sec] & 13.7 [12.4, 16] & 7.1, 100 & 4.90 & 11 \\ Magnesium [mg/dL] & 2.1 [1.9, 2.3] & 1.0, 14.2 & 0.70 & 1.9 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Description of the variables used in this study. For numeric variables, the median and 1 st and 3 rd quartile are presented, whilst for binary variables, we present the prevalence (as a percentage). The last two columns display the level of missing values (as a percentage) and the imputed value used, respectively. GCS stands for Glasgow Coma Scale.
## 3 Experiment
### Data Processing
#### 3.2.3 HI Build  
In the RUL prediction problem of rolling bearings, the accurate construction of bearing Health indicators (HIs) is the key to improving the accuracy of RUL predictions. However, most of the existing HI construction methods select the indicators that can reflect the degradation of the bearing as HIs from the time or frequency domain of the vibration signal, and such methods are overly dependent on the experience of experts and also require a certain degree of understanding of the degradation mechanism of the equipment, which has greater limitations [36]. To this end, We propose a new HI construction method, which firstly reduces the noise of the bearing vibration signal by discrete wavelet transform, then normalizes the data to 0-1 by maximum-minimum normalization, and then takes the noise-reduced and normalized vibration signal as the HI of the bearing. This method not only makes full use of the vibration signal, but also improves the stability of the model training, reduces the variability of features, and improves the generalizability of the model.
# The Effectiveness of Unimodal and Multimodal Warnings on Drivers' Response Time: A Meta-Analysis
## 4 Discussion
### MIE of Driving Warnings Reveals a Positive Trend with the Number of Modalities  
The relationship between MIE and the number of applied modalities in a driving warning system was explored by comparing unimodal, bimodal, and trimodal warnings against each other. Results from the comparisons between unimodal and bimodal warnings showed that auditory-tactile bimodal warnings outperformed unimodal warnings. Furthermore, comparisons between bimodal and trimodal warnings revealed a non-significant shorter response time under trimodal warning conditions.
## 2 Related Work
### Attack Model  
Existing work focuses on how to deal with attacks in different scenarios. In [26], the authors proposed reciprocity of \(k\)-clusters to achieve strong \(k\)-anonymity. In this method, \(k\) users remain unchanged in several queries in a short time so that an attacker cannot identify users by intersecting several \(k\)-clusters of different queries. In [27], the authors studied the scenario in which different users sent query requests in the same location and proposed L2P2. The L2P2 adopted a distributed architecture and introduced location labels to classify locations of mobile users to sensitive and ordinary locations. When users' locations in the anonymous group were the same and were all located in sensitive locations, they exchanged ID with each other to achieve the anonymous effect. The method in [13] pointed out that, for long-term cumulative sporadic queries and continuous queries, attackers could deduce users' privacy by collecting and analyzing users' historical data, called LSA and RSA attacks. The method in [20] proposed MNAME and SNAME to resist LSA attacks and raised REGP to resist the RSA attack. In these methods, refs. [13; 20; 26] mainly focused on scenarios where a user sent a query in different locations, and [27] mainly focused on scenarios where the user sent queries in the same locations without considering short-time continuous query and difficult to resist LSA and RSA attacks. However, for continuous queries in the same location in a long time, the users in the anonymous group are not always identical, causing the real user to be able to be inferred by comparing multiple queries. Hence, in this paper, we mainly study the attack (I2 LC) which a user might suffer and how to resist it in the scenario of this paper.  
There are also several works related to the HSA and meshing methods to divide a city area. The method in [32] pointed out that privacy-related attributes have a hierarchical structure, and studied achieving \(k\)-anonymity by clustering in attribute hierarchical structures. The method in [33] pointed out that the level of location privacy relied on the HSA and location privacy protection needed to consider the HSA. For example, for \(k-1\) dummy locations and a real location, which all locate in BUPT, although an attacker cannot distinguish the real location, he knows that the user is in BUPT. In addition, the method in [27] divided an area based on sensitive locations and ordinary locations. The method in [13] divided an area based on the probability of locations. While they do not consider the HSA. In our paper, we consider the HSA and divide an area into different grids with the two-level structure based on the organization.
# Sand and Dust Storms: Impact Mitigation
## 5 Policy Measures for SDS Impact Mitigation
### Policy Lessons, Failures and Inadvertent Impacts
In the broadest sense, social capital refers to the interconnectedness among individuals in a society and considers relationships as a type of asset, and there is some evidence to suggest that social capital can both create incentives and remove barriers to the adoption of soil conservation practices ([PERSON] and [PERSON], 2016). Government support for social capital has been identified as an element in the success of Landcare in Australia, for example ([PERSON] and [PERSON], 2016). Whatever approaches are adopted to facilitate the achievement of SDS policies aimed at source mitigation, knowledge of local circumstances is always likely to be critical. One interesting illustration of this axiom is provided in a study of subsistence farmers in Niger (Niger, 2012). The researchers concluded that, although wind erosion rates were very high, local farmers had to balance this realization with \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Initiative** & **Year Established** & **Jurisdiction** & **Authority** & **Purpose/Mission** \\ \hline Alberta No-Till & & Alberta & Nonprofit & Promote use of tillage practices to reduce soil erosion \\ Farmer’s Association & & & & \\ \hline Manitoba-North & & & & \\ Dakota Zero Tillage & 1982 & & & \\ Farmer’s Association & & & & \\ (MNDZTFA) & & & & \\ \hline Alberta Conservation & & & & \\ Tillage Society & & & & \\ \hline Saskatchewan Soil & & & & \\ Conservation & 1987 & & & \\ Association & & & & \\ \hline Soil Conservation & 1987 & & & \\ Council of Canada & 1987 & & & \\ \hline Alberta Soil & 1988 & Alberta & Provincial & \begin{tabular}{c} Impose duty on landholders to protect soil resources \\ \end{tabular} \\ Conservation Act & & & & & \\ \hline Pembina Valley & & & & \\ Conservation District & & & & \\ \hline No-Till on the Prairies & 1991 & North America & Nonprofit & \
\begin{tabular}{c} Provide information to farmers \\ on adopting zero-tillage \\ \end{tabular} \\ \hline Zero Tillage & & & & & \\ Production Manual & 1991 & General & MNDZTFA &
\begin{tabular}{c} Provide answers to questions \\ about zero-tillage farming \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Wind erosion control initiatives on the Canadian Prairies in and around the 1980s (after (2017)). much more pressing agricultural issues such as poor soil quality, unreliable rainfall and uncertain political and economic environments. Another facet of source mitigation that should be kept in mind is the possibility that some policy measures may not have the consequences intended. [PERSON] et al. (2016) cite an example from wind erosion control policies in Europe where an incentive to set aside former farmland did not reduce the wind erosion risk because insufficient vegetation cover developed on the poor sandy soils.
## 3 Results and Discussion
### 1/f (Low-Frequency) Noise
These measurements were conducted at 10 Hz and for devices with an \(L_{g}\) of 50 nm. The determined values of \(S_{Vfb}\) were 2.2 \(\times\) 10\({}^{-12}\) and 3.1 \(\times\) 10\({}^{-12}\) V\({}^{2}\cdot\)Hz\({}^{-1}\) for LM-HEMTs and MHEMT, respectively. Correspondingly, the calculated \(N_{t}\) values were 3.27 \(\times\) 10\({}^{16}\) eV\({}^{-1}\cdot\)cm\({}^{-3}\) for LM-HEMTs, while for the MHEMT, it was 3.56 \(\times\) 10\({}^{17}\) eV\({}^{-1}\cdot\)cm\({}^{-3}\). MHEMT has a trap density one order higher than LM-HEMTs.
###### Abstract  
Multi-layer graphene (2-10 layers), also called graphene nanoplatelets (GNPs), is a carbon-based nanomaterial (CBN) type with excellent properties desirable for many biomedical applications. Despite the promising advantages reported of GNPs, nanoscale materials may also present a potential hazard to humans. Therefore, in this study, the in vivo toxicity of these nanomaterials at a wide range of concentrations from 12.5 to 500 \(\mu\)g/mL was evaluated in the _Caenorhabditis elegans_ model for 24 h (acute toxicity) and 72 h (chronic toxicity). Furthermore, their in vitro toxicity (from 0 to 10 \(\mu\)g/mL for 12 and 24 h), proliferative activity at 72 and 96 h, and their effect on the expression of thirteen genes in human keratinocytes HaCaT cells were studied. The physico-chemical and morphological aspects of the GNPs used in this study were analyzed by Raman scattering spectroscopy, electron microscopy, zeta potential as a function of pH, and particle size measurements by dynamic light scattering. The results of this study showed that GNPs showed in vivo non-toxic concentrations of 25 and 12.5 \(\mu\)g/mL for 24 h, and at 12.5 \(\mu\)g/mL for 72 h. Moreover, GNPs present time-dependent cytotoxicity (EC\({}_{50}\) of 1.142 \(\mu\)g/mL and 0.760 \(\mu\)g/mL at 12 h and 24 h, respectively) and significant proliferative activity at the non-toxic concentrations of 0.005 and 0.01 \(\mu\)g/mL in the HaCaT cell line. The gene expression study showed that this multi-layer-graphene is capable of up-regulating six of the thirteen genes of human keratinocytes (_SODI_, _CAT_, _TGFB1_, _FN1_, _CDH1_, and _FBN_), two more genes than other CBNs in their oxidized form such as multi-layer graphene oxide. Therefore, all these results reinforce the promising use of these CBNs in biomedical fields such as wound healing and skin tissue engineering.  
graphene nanoplatelets; human keratinocytes; toxicity; proliferative activity; gene expression; _Caenorhabditis elegans_
## 4 Case Studies
### Discussion  
#### 4.3.1 Comparison of Different Cases  
In order to better analysis the effect of the active power dispatch of ESSs and the reactive power regulation of DGs and ESSs, four cases are used for comparative analysis as follows.  
Case 1: Both the active power dispatch of ESSs and the reactive power regulation of DGs and ESSs are not considered;  
Case 2: Only active power dispatch of ESSs is considered;  
Case 3: Only the reactive power regulation of DGs and ESSs is considered;  
Case 4: Both the active power dispatch of ESSs and the reactive power regulation of DGs and ESSs are considered.  
The comparison of optimization results under different cases are shown in Table 5.  
Comparing Case 1 with Case 2 and Case 3 with Case 4 of the two distribution networks, we can find that active power dispatch of ESSs helps reduce the operation cost while there is little difference in the network losses. It implies that ESSs mainly reduce the operation cost by shifting load from high electricity price hours to low electricity price periods. Comparing Case 1 with Case 3 and Case 2 with Case 4, it can be seen that the network losses are further decreased by taking the reactive power regulation of DGs and ESSs into consideration. Therefore, the total operation cost is reduced as well. In addition, the voltage deviation is better improved. According to Case 4, the active power losses, the operation cost, and voltage deviation are all lowest when co  
Figure 11: Bus voltage amplitude of 69-bus distribution network.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Case**} & \multicolumn{2}{c}{**33-bus Distribution Network**} & \multicolumn{2}{c}{**69-bus Distribution Network**} \\ \cline{2-7}  & \(P_{\text{loss }}\)**(kW)** & \(C_{\text{cost }}\)**(\(\mathbf{\mathsf{\hat{V}}}\)) & \(\Delta\mathbf{U}\)**(pu)** & \(P_{\text{loss }}\)**(kW)** & \(C_{\text{cost }}\)**(\(\mathbf{\mathsf{0}}\))** & \(\Delta\mathbf{U}\)**(pu)** \\ \hline Case 1 & 1388.95 & 48,819.63 & 17.08 & 2303.60 & 50,892.86 & 41.47 \\ Case 2 & 1383.71 & 48,001.09 & 16.20 & 2313.05 & 50,095.00 & 39.87 \\ Case 3 & 1173.97 & 48,635.31 & 15.29 & 1681.35 & 50,383.46 & 35.83 \\ Case 4 & 1144.56 & 47,798.40 & 13.94 & 1564.78 & 49,479.71 & 33.08 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Optimization results of the two distribution networks under different cases.  
active/reactive power is conducted. Therefore, as information and communication technologies advance, coordinated optimization is a better choice for distribution system operators.
# Investigation of the Effect of Capillary Barrier on Water-Oil Movement in Water Flooding
###### Abstract  
Water flooding technology is widely used to improve oil recovery efficiency in oilfields. The capillary barrier effect induced by the complex pore structures in the reservoir rocks is a crucial reason for the trapping of a great deal of residual oil in oil reservoirs after water flooding. However, the formation condition along with the effect on the recovery rate of the capillary barrier under different wettability conditions should be investigated further. To bridge the gap between the microscopic mechanism of the capillary barrier effect and the macroscopic mechanism of oil displacement efficiency, a simple conceptual capillary model is constructed to obtain the formation conditions of the capillary barrier using the analysis method, and its influence on macroscopic oil displacement efficiency in the porous media model with an opening angle of 45\({}^{\circ}\) is systematically investigated in this study using direct numerical simulations (DNS) coupled with the volume of fluid method. The results showed that the capillary barrier effect plays a significant role in the formation of the residual oil in the reservoir rock and the contact angle and the opening angle are the primary factors for the formation of the capillary barrier. The capillary force is the driving force when the oil-water interface advances in the throat channel under water-wet conditions, while the capillary force hinders the movement of oil-water movement when the liquid flows out of the throat channel and when \(\theta+\beta>90^{\circ}\). Furthermore, the highest oil displacement efficiency is achieved at the intermediate capillary number and in the case that the minimum conditions of occurrence of the capillary barrier phenomenon are satisfied. This is of great significance for controlling the optimized contact angle to further enhance the oil recovery rate of current oil reservoirs using waterflooding technology.  
capillary barrier; flow in porous media; pore-scale simulation; enhanced oil recovery; wettability Article
## 3 Proposed Algorithms  
As already mentioned above, in the research work presented in this article two different optimization algorithms were developed, i.e., a GA and a PSO algorithm. Basic prerequisite for the proper function of each of these two algorithms is the knowledge of the characteristics of the search space, where the wireless sensor network will be placed, as well as the population and the behavior of the sensor nodes which comprise it. It is assumed that the search space is squared, two-dimensional, and without any obstacles. Therefore, the sensor nodes are not affected as far as the position they can occupy is concerned, since they remain within the search space limits, and the sensing range is not affected by extrinsic factors. A significant parameter that has an effect on the final positions of the sensor nodes is the existence of points of interest (POI) which require k- coverage. The sensor nodes' function is based on the binary-disc sensing model, according to which they have 100% detection ability within the sensing range. The algorithms that have been designed entail two basic aims:  
* The maximization of the coverage area with the use of a certain number of sensor nodes.
* The attainment of k-coverage in predefined points in the area.  
Basic points towards finding the solution to such kind of problems with the use of CI methods are the input information encoding and the creation of an apt function that describes the problem.