esa-sceva/satcom-chunk-collection huggingface dataset:
# Performance of Molasses Waste as a Cement Replacement to Study Concrete Compressive Strength
## 2 Materials and Methods  
In this study, six different dosages of molasses waste were incorporated in a concrete mix by replacing the cement content to cast the specimens to study their effect on the concrete compressive strength. These dosages were included to obtain a definite trend of the molasses effect on concrete compressive strength in terms of cement replacement and to obtain an optimum value of the molasses replacement ratio yielding maximum compressive strength. The DG Khan ordinary Portland cement was used in the research. It was finely grounded to ensure better workability and to increase the surface area for an effective hydration process. Lawrencepur sand was chosen as the fine-grained material, capable of passing through a 4.75 mm sieve. The specific gravity of the sand used in the study ranged from 2.5 to 2.64, determined as per ASTM C 128 [46]. Carefully selected and properly graded fine aggregates were utilized to ensure optimal performance. Margalla Crush is a crushed aggregate widely used in the Margalla Hills region of Pakistan. Margalla Crush was used as a coarse aggregate in this study. The size range of the coarse aggregate was 12.5 mm to 19 mm and its specific gravity was 2.7, determined as per ASTM C 127 [47]. Tap water was used for the concrete and the curing of concrete samples as per the guidelines of ACI code 211.1 [48]. Molasses waste is the residue, by-, or co-product left over after the extraction of sugar. It is a thick, dark syrup obtained from the processing of sugar cane or sugar beet. The molasses waste used in this study was obtained from Sillanwali Sugar Mills. The pH of the molasses waste was 5.1, and the water content ranged from 19 to 24%. The percentage of sucrose in the molasses waste ranged from 32 to 38%. The water/cement  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Type of Concrete** & **Slump (mm)** & \multicolumn{3}{c}{**Compressive Strength (MPa)**} \\ \hline  & & 7-day & 28-day & 56-day \\ \hline O.P.C. & 140 & 18.40 & 30.50 & 33.35 \\ Fly Ash Concrete & 130 & 16.10 & 29.30 & 31.00 \\
0.25\% Molasses & 115 & 17.50 & 29.00 & 30.00 \\
0.20\% Molasses & 105 & 22.00 & 33.40 & 40.00 \\
0.15\% Molasses & 95 & 20.93 & 42.10 & 44.16 \\
0.10\% Molasses & 85 & 22.45 & 39.60 & 40.50 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Slump and compressive strength results. O.P.C. = ordinary Portland cement. Reproduced from [43].  
ratio was the same for all concrete mixtures at 0.505. The mix design ratio of 1:1.9:2.3 was used, determined using ACI code 211.1:1991 [48]. The concrete was mixed in a drum mixer. The molasses waste for six dosages of 0.25% wt. of cement (28.85 g), 0.5% wt. of cement (57.7 g), 0.6% wt. of cement (68.7 g), 0.75% wt. of cement (86.55 g), 1% wt. of cement (113.6 g), and 2% wt. of cement (230.8 g) was obtained by weight of cement according to the percentage of cement replaced in that specific dosage. Table 2 shows the mix proportions used in this research.
# Effects of Grout Compactness on the Tensile Behavior of Ground Splice Sleeve Connectors
## 2 Tensile Tests on GSS Connectors with Different Compactness
### Test Setup and Loading Process  
To determine the material property, nine 40 mm \(\times\) 40 mm \(\times\) 160 mm prismatic specimens in three groups were fabricated. They were cured under the same condition as the GSS in line with Grouting Material for Steel Sleeve Connection [2] and Strength Testing Method for Cement Mortar [27]. After curing, the average compressive strength of the grout was measured at a loading rate of 2400 \(\pm\) 200 N/s, and the compressive strength is 88.5 MPa, and more details were shown in Table 2. The strength grade of the spliced rebar is HRB400 [28]. The material properties of the four types of rebar, with three specimens each, were obtained in accordance with Tensile Testing of Metallic Materials-Part 1: Test Methods at Room Temperature [29], and the average mechanical properties are shown in Table 3.  
Compared with the criterion of the Chinese core [26], the strength and fluidity of the grout meet the specification requirements.  
Where \(d_{b}\) is the diameter of rebar, \(f_{y}\) and \(f_{u}\) are the yield strength and the ultimate strength of rebar, respectively, \(\varepsilon_{y}\) is the yield strain of rebar, \(E_{s}\) is the modulus of elasticity, \(\
u\) is the Poisson's ratio, and \(A\) is the elongation ratio, which is the elongation of the length as a percentage of the original length.  
The tensile tests of the GSS connectors were carried out with a 600 kN capacity electro-hydraulic servo universal testing machine. Figure 5 shows the test setup. Two linear variable differential transducers (LDVT) were arranged at both side of the grout sleeve to monitor the vertical deformation. Strain gauge 1 and 2 were set in the bar outside the pipe sleeve to measure the bar strain. Strain gauge 3 was set on the pipe wall along the longitudinal direction to measure the strain distribution of the sleeve during tensile loading. Strain gauge 2 was set on the pipe wall along the transverse direction to measure the hoop strain. The loading process was divided into two stages. The first stage adopted force loading until the spliced rebar yielded, and the loading rate was 0.5 MPa/s. The second stage adopted displacement control loading. The separation rate of the two chucks was no more than 20-35 mm/min.  
In order to observe the strain change of the rebars and sleeves under tensile load, the strain data of the most critical cross section of the rebars and the sleeves were collected. The strain gauge placement and the measuring point arrangement on rebars and sleeve surface are shown in Figure 5.
## 1 Introduction
### Decoupling of Active and Reactive Powers
This paper is organized as follows: the next section presents the modeling of the VSCs with an LCL filter in a dq reference frame; in Section 3, the proposed current controller is explained as well as an estimation of LCL filter-state variables and explanation of DC-link voltage and reactive power control loops; in Section 4, a phase margin determination scheme is presented, which provides a systematic method for tuning the proposed current control parameters; performance of the final controlled system in different situations is evaluated through different case studies in Section 5; finally, Section 6 concludes the paper. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \begin{tabular}{c} **AD Method** \\ **Proposed Method** \\ \end{tabular} & \begin{tabular}{c} **Single Loop** \\ **Methods** [6–8] \\ \end{tabular} & \begin{tabular}{c} **Multi Loop Methods** \\ **(Capactor or Inverter** \\ **Currents Are Fed back** \\ **as Inner Loop)** \\ \end{tabular} & \begin{tabular}{c} **Multi Loop Method** \\ **(Capactor Volages Are** \\ **Ref back as Inner** \\ **Loop)** \\ \end{tabular} & \begin{tabular}{c} **Predictive, Adaptive,** \\ **and Robust Methods** \\ **Loop)** \\ \end{tabular} \\ \hline \begin{tabular}{c} Stability margin and \\ resonance damping capability \\ \end{tabular} & high & low & high & medium & high \\ \hline \begin{tabular}{c} Number of sensors \\ (Except to Vg) \\ \end{tabular} & 3 current sensors & 3 current sensors & 6 current sensors & 3 current sensors & 6 current sensor and \\ \begin{tabular}{c} (Except to Vg) \\ \end{tabular} & 3 current sensors & 3 current sensors & 6 current sensors & 3 voltage sensors & \begin{tabular}{c} 6 current sensor and \\ may be 3 \\ voltage sensors \\ \end{tabular} \\ \hline \begin{tabular}{c} Decoupled control of active \\ and reactive currents \\ \end{tabular} & \
\begin{tabular}{c} Completely \\ decoupled \\ \end{tabular} & no & no & no \\ \hline
\begin{tabular}{c} Complexity and order \\ of controller \\ \end{tabular} & medium & medium & medium or low & medium or low & high \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Different active damping control schemes for a grid-connected inverter with LCL-filter.
# Secure Watermarking Schemes and Their Approaches in the IoT Technology: An Overview
## 2 The Concept of Watermarking
### Embedding Domain  
In the embedding phase, the watermarking techniques can be categorised into spatial domain (time) or transform domain (frequency). Therefore, the aim of hiding information is to preserve the availability of the secret message, which is usually being undetermined by an unauthorised access [35]. Various hidden algorithms are used in embedding watermarks that range from as simple as Least Significant Bit (LSB) to sophisticated transformation techniques, such as DWT, Discrete Fourier Transform (DFT), SVD and Discrete Cosine Transform (DCT) (see Figure 3).  
As illustrated in Figure 3, the original object represents the input, and the hidden algorithm is applied through the process of embedding the watermark. Following that, the output represents the watermarked object. The hidden algorithms are discussed in detail as follows:
## 3 Results and Discussion
### Effect of Rubber Fibers on Pore Size Distribution
As shown in Figure 12a, the pore diameters of the ESR were less than 0.5 \(\upmu\)m. This reflected the tight pore structure inside the sample. After the addition of an appropriate amount of rubber fiber (5-10%), Amplifying the ESR pore size distribution curve, it was found that with the increase of rubber content, the ESR pore size distribution curve shifted to the left, and the proportion of peak pore size distribution decreased first and then increased. This indicated that the porosity of expansive soil could be reduced by adding rubber fiber. The pore content curves of the ESR with different rubber fiber contents are shown in Figure 12b. From Figure 12b, the ESR micropores accounted for the largest percentage of the number of pores. It was followed by the ultra-micropores, and the fewest number of small pores. The pore size inside the ESR was mainly distributed between 0.01 \(\upmu\)m and 0.2 \(\upmu\)m. The pore size of approximately 0.02 \(\upmu\)m accounted for the largest proportion (approximately 4.2% of all the pores in the ESR). The addition of an appropriate amount  
Figure 11: \(T_{2}\) spectrum for different rubber fiber contents. \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{2}{c}{**Beginning and Ending Relaxation Times of Spectrum Peaks**} \\  & **(ms) (Peak Percentage)** \\ \cline{2-3}  & **Primary Peak** & **Secondary Peak** \\ \hline ESR-8 & 0.561–9.011 (97.6\%) & 9.659–36.123 (2.4\%) \\ ESR-9 & 0.455–7.843 (97.6\%) & 8.407–33.701 (2.4\%) \\ ESR-10 & 0.488–8.407 (97.4\%) & 9.011–31.440 (2.6\%) \\ ESR-11 & 0.644–9.011 (97.3\%) & 9.659–36.123 (2.7\%) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: \(T_{2}\) spectrum distribution of the ESR for different rubber fiber content. of fiber (5-10%) decreased the proportion of small pores and micropores and increased the proportion of ultra-micropores. However, the addition of more rubber fibers (15%) increased the percentage of small pores and micropores. This weakened the internal structure of the sample.
## 3 Dynamic Prediction of Servo Valve Performance Degradation
### Servo Valve Erosion and Wear Test
#### 3.1.2 Design of Experimental Conditions  
1. Oil contamination level According to GJB 420B-2015 \"Classification of solid contamination in aviation working fluids\" [28], the classification was based on the size, particle number, and distribution of solid contaminants in the fluid, as well as the content of solid contaminants per unit volume of working fluid. The standard denotes specific particle size ranges by the letters A, B, C, D, E, and F. The solid contamination is classified into 15 classes according to the maximum limiting number of particles in these six size ranges contained in 100 mL of working fluid.  
In this test, the physical failure model was simplified and the diameter of the maximum number of solid particles in the fluid was used to reflect the different fluid contamination levels. Considering the actual application environment of DDV, four different contamination levels of hydraulic fluid were proposed in this test: GJB420B-6, GJB420B-7, GJB420B-8, and GJB420B-9.  
2. Opening degree The simulation data showed four different openings of 0.1 mm, 0.2 mm, 0.3 mm, and 0.4 mm, which were selected.  
3. Differential pressure As the opening and differential pressure together affect the flow rate of the valve and the flow rate of the inlet, the differential pressure also needs to be taken into account. In view of the limitations of the experimental conditions, four different differential pressure conditions of 14 MPa, 16 MPa, 18 MPa, and 20 MPa were selected.  
The entire orthogonal experimental working conditions are shown in Table 1 below. According to GJB3370-1998 \"aircraft electro-hydraulic flow servo valve general specifications\" [29], the total life of the servo valve needed to have 600 Fh for its high pollution test, so for each sample test for 500 h, every 50 h between the disassembly of the spool valve sleeve, there was cleaning and debridement treatment. Because the liquid oil temperature is difficult to control during the experiment, the oil temperature was not used as one of the experimental conditions for the time being. The initial oil temperature was set at 35 \({}^{\circ}\)C, which is commonly used in the industry.
# A Joint Dual-Frequency GNSS/SINS Deep-Coupled Navigation System for Polar Navigation
## 3 Deep-Coupled Navigation System Design
### Joint Vector-Tracking-Based System Structure  
The GNSS/SINS deep-coupled system has several kinds of deep-coupled structures which have been discussed in [19; 21; 22]. In this paper, a federated filtering architecture with a coherent prefilter algorithm will be designed in the following subsections.  
Figure 2 shows a block diagram of the combined L1 C/A and L2 CM vector-tracking-based GNSS/grid SINS deep-coupled navigation system structure, including two main function designs for vector-tracking prefilters and the integrated navigation filter. The system works as follows:Firstly, the sampled IF GNSS signals are passed through a bank of correlators to produce early, prompt, and late \(I\) and \(Q\) outputs for each frequency band of satellites. Then, the joint coherent prefilters directly use these I and Q correlator outputs as the measurements to estimate the phase and frequency error states of the tracking at a relatively high rate. The outputs from these prefilters are next converted to pseudorange and pseudorange rate residuals and used in the integrated navigation filter to implement the deep-coupling at a relatively low data rate. The integrated navigation filter enables the interaction between channels and also uses the grid SINS information to update the navigation states. Finally, the system utilizes the predicted position, velocity, and frequency changes to generate NCO feedback commands to the local signal generator for both L1 C/A and L2 CM signal generation. Meanwhile, the SINS correction information is also fed back to correct the errors of the grid SINS.
###### Abstract  
Improvements in immersive technology are opening up new opportunities for land management and urban planning, enabling the creation of detailed virtual models for examining and simulating real-world short-, medium-, and long-term scenarios. The goal of this research is to present the creation of an urban digital twin based on a virtual reality city replica, that models and visualizes the urban environment in three dimensions using advanced geomatics techniques and IoT technologies. The methodology focuses on two case studies that utilize environmental analysis and virtual simulation: assessing hydrogeological risk and evaluating public light pollution. The Cesium platform was employed to build high-precision 3D models based on topographic, meteorological, and infrastructure data. The proposed methodology calculated a correlation between light pollution and CO\({}_{2}\) equal to 0.51 and a correlation between precipitation, slope, and risk area higher than 0.80. The most critical and high-risk classes are as follows: Dense Discontinuous Urban Fabric, Roads and Associated Lands, Pastures, and Forests. Results show how an urban digital twin can be a powerful tool for monitoring and territorial planning, with concrete applications in the public and risk management fields. This study also highlights the importance of geomatics technologies in the creation of realistic and functional virtual environments for the assessment and sustainable management of urban resources.  
urban digital twin; cesium; IoT; remote sensing; GIS; simulation Article
# A Secure and Efficient Three-Factor Authentication Protocol in Global Mobility Networks
## 6 Security Analysis
### Informal Security Analysis
#### 6.1.4 Session Key Disclosure Attack  
In our protocol, a \(MU_{a}\) cannot compute \(\{M_{1},M_{2},Q_{M}\}\) because a legitimate mobile user \(MU\) generates an authentication request message by using the dynamic random nonce \(R_{MU}\) and secret parameter \(X_{i}\). Consequently, the proposed protocol protects against session key disclosure attacks.
# Cybersecurity and Medical Imaging: A Simulation-Based Approach to DICOM Communication
## 2 Background
### Application Entities (AEs)  
The AE concept [42] is fundamental to Digital Imaging and DICOM standards. It represents a node or device in a network that communicates using DICOM protocols. An AE can be a piece of medical imaging equipment, such as a CT scanner, MRI machine, or PACS server. In the context of DICOM, an AE is identified by a unique AE title, which serves as its network address. The AE title is used to establish connections and enable communication between different entities in a DICOM network. Each AE is responsible for sending and receiving DICOM objects, including medical images, patient information, and related metadata.  
AEs provide services such as querying/retrieval, storage, and printing of DICOM objects. They can act as a Service Class Provider (SCP), which receives requests for services, or a Service Class User (SCU) [42], which initiates requests and interacts with other endpoints. The roles of SCPs and SCUs can be performed by the same AE or by different endpoints depending on the system architecture and requirements. An Application Entity represents a DICOM node or device in the network. In the DICOM simulator, an AE is created using the AE class from _Pynetdicom_. The AE title is set to _\"MODALITY\"_, which identifies the simulated modality in the network.
# Cross-Layer Optimization for Heterogeneous MU-MIMO/OFDMA Networks
## 3 Network Model and Assumptions
A single spatial stream is allocated to flow 2 on link \(0\to 2\), while two spatial streams are allocated to flow 3. In this case, the sum-rate becomes 12 (\(=4+8\)), which is larger than that for OFDMA. Figure 1c shows the case of joint use of MU-MIMO and OFDMA. In this case, each OFDMA transmission can have multiple spatial streams. For example, over subchannel 1, node 0 transmits two types of data to node 1: the data for flow 1 with one spatial stream, and the data for flow 2 with two spatial streams. In this case, the sum-rate is 12 (\(=3+3+6\)). Since the maximum bandwidth is 80 MHz (i.e., four subchannels) and the number of antennas for the transmitter is three, the maximum achievable capacity of the network in this example is 12, which is obtained both using MU-MIMO (Figure 1b) and OFDMA and MU-MIMO jointly (Figure 1c). Although this result suggests that the joint use of OFDMA and MU-MIMO does not give any advantage in terms of increasing the network capacity, and does not seem to be of much benefit, it enables a more flexible resource allocation than when only one of the two technologies is used, thereby helping increase the overall performance, as will be discussed later in Section 5.2.
## 2 Literature Review  
### Barrel End Milling Technology  
Barrel end-milling, also known as Parabolic Performance Cutting (PPC) or tangential milling, represents a significant evolution in the field of machining, being a further development of ball-nosed end milling [1,2]. This relatively new technique involves the use of cutters with specific geometries, such as circular segment end mills and conical cutters, commercially known as turbine cutters, designed to optimize the machining of complex surfaces [3]. The complex geometries of these cutters allow for more efficient machining of 3D surfaces, reducing machining time compared to traditional methods [4,5].  
Unlike traditional ball-nosed end mills, which have almost point-like contact with the workpiece, barrel tools have a larger contact area, which allows for the use of larger cutting depths and, consequently, increased productivity [6]. This characteristic makes them particularly effective in applications such as die and mold machining, aerospace component machining, and the machining of other complex 3D parts [7].  
Research has also explored in detail aspects such as surface topography, cutting forces, and tool runout in barrel milling to further optimize the process. This characteristic makes them particularly effective in applications such as die and mold machining, aerospace component machining, and the machining of other complex 3D parts [8; 9; 10; 11; 12].  
The efficient implementation of PPC milling typically requires the use of a modern 5-axis CNC machine tool and advanced CAM software [13]. While CAM software allows for complex tool geometries to be processed as data models, thus ensuring precise toolpath control and optimization, the physical limitations of 3-axis machines still pose a challenge for certain applications like high-speed finishing of complex geometries [14]. Barrel end-milling (PPC) is commonly used with 5-axis CNC machine tools. 5-axis machines offer the freedom to orient the tool relative to the workpiece in multiple directions, which is essential to fully exploit the advantages of barrel tools and to machine complex surfaces with high efficiency [15; 16]. This ability to control tool orientation allows for maintaining optimal contact between the tool and the workpiece, maximizing the material removal rate and surface quality [17; 18].  
However, barrel end-milling on 3-axis CNC machine tools presents a significant challenge. 3-axis machines have limitations in tool orientation, which makes it difficult to maintain the optimal orientation of the barrel tool relative to the workpiece. To overcome these limitations, specific workpiece positioning relative to the cutter is necessary, so that during the tool's movement, the position of its axis respects the programming angle. This is often achieved by using specialized fixtures that orient the workpiece at the correct angle. The design and implementation of these fixtures are an essential aspect of adapting barrel end-milling to 3-axis machines.