esa-sceva/satcom-chunk-collection huggingface dataset:
## 1 Introduction
Data rate is increased because a greater number of bits are transmitted within the same symbol period. This translates to spectral efficiency because the same bandwidth is used for more bits per second. The data rate improvement is also necessary because the performance of LPWANs is limited by duty cycle regulations. The duty cycle percentage available for a sensor node can be more efficiently used if more data can be transmitted during that time. In case of LPWANs and sensor networks, active transmission is the most power intensive mode [21; 22]. Use of higher order modulations can also improve energy efficiency, because in higher order modulation, the same symbol energy is used to encapsulate more amount of information than a lower order modulation [23]. However, these improvements come at the cost of higher BER. This degradation in error performance can be overcome by selecting a higher sampling rate at receiver so that the signal can be received at large number of polarization angles and more choices for polarization selection are available to detect the message signal. Higher order modulations also add complexity to transmitter and receiver architecture. The structure of RPW transmitter is complex because two separate and non-identical PSK modulators are used [24] unlike PD that employs a single modulator. Secondly, as discussed above, channel models used for PD have limitations in terms of complexity and modeling inaccuracies. Therefore, the conventional models for PD systems must be avoided, as this will further increase the complexity in simulation and performance evaluation. The quaternion model can significantly reduce the complexity in performance analysis and simulation of RPW communication. Therefore, this paper has made the following contributions to improve RPW system:  
1. Rotating Polarization Multiple Phase Shift Keying (RP-MPSK) modulation is proposed. 2. Novel quaternion model for RPW communication (Q-RPW) is proposed. The complexity of channel model is halved as compared to classical PD model by using four real random numbers instead of eight for channel modeling. The model is applied to RP-MPSK modulation for BER performance evaluation over Rayleigh fading and interference. 3. Receiver sampling rates for higher order modulations are recommended to make their BER performance compatible with RP-BPSK. The remaining parts of this paper are organized as follows: Section 2 shows improvement of RPW from RP-BPSK to RP-QPSK and then generalization to RP-MPSK. Q-RPW is proposed in Section 3 and mathematical treatment is presented. BER performance of RP-MPSK is evaluated by simulating the proposed model in Section 4. RP-MPSK modulation is also compared with leading LPWAN modulations. The section also investigates the effect of increase in sampling rate on RP-MPSK to maintain the error performance. Section 5 concludes the contributions and findings of the paper.
## 1 Introduction  
The exponential growth of data traffic has created higher data rate requirements for electronic components [1]. To meet the increasing demand among computational blocks, communication links with data rates exceeding hundreds of Gb/s [2] are needed. Compared with telecommunication, multilane optical communication [3] has been widely used for its excellent capability [4].  
In previous research, several multilane optical receivers with high-speed data rates and noise optimization have been developed [5; 6; 7; 8; 9; 10; 11] in CMOS and SiGe BiCMOS technology. A multilane optical receiver with data rates exceeding hundreds of Gb/s was first functionally realized by [PERSON] [2] in 2015. In order to explore performance enhancement of the optical receivers, a wide-band design of the receivers was analyzed by [PERSON] [12] in 2019, a noise optimization method was proposed by [PERSON] [9] in 2016, and power and area reductions in advanced CMOS technology were made by [PERSON] [13] in 2019. However, there still exist some shortcomings which need to be improved in these receivers, such as bad compatibility with more than one specific operating mode; complicated trade-offs among stability [14], bandwidth, and noise [9] of the input transimpedance amplifier (TIA) stage; and high manufacturing costs due to the large chip area in SiGe BiCMOS technology, etc.  
In this paper, we present an area-efficient noise-optimized programmable 4 x 25-to-28.9 Gb/s optical receiver for a multilane optical fiber system in 0.13 um SiGe BiCMOS. With a flexible power mode and received signal strength indication (RSSI) function, the proposed optical receiver works at 4 \(\times\) 25-to-28.9 Gb/s data rates and provides variable gain and output swing, etc. In order to avoid intersymbol interference (ISI) for instability of the input TIA stage, the stability of the input TIA stage is improved with the introduction of emitter degeneration. Meanwhile, a noise model of the input TIA stage with emitter degeneration is analyzed. Then, an improved noise optimization method based on the noise model and parameter scaling is proposed. As a result, complicated trade-offs among noise, bandwidth, stability, and S11 (scattering parameters) are avoided. To reduce the chip area, the capacitors in the lowpass filters of the DC offset cancellation (DCOC) loop are omitted due to parasitic capacitor utilization and capacitive emitter degeneration, rather than the commonly used large-sized passive inductors, applied to bandwidth extension in the variable-gain amplifier (VGA) stage. Additionally, the sink current source with emitter degeneration reduces the input-referred noise of the receiver which is introduced by the DCOC circuit.  
This paper is organized as follows. The chip architecture is introduced first in Section 2. Then, detailed circuit designs are presented in Section 3, followed by the measurement results in Section 4. Finally, conclusions are drawn in Section 5.
# Flexible Phased Antenna Arrays: A Review
## 2 Manufacturing Techniques  
Advancements in FPA systems are largely driven by the development of different manufacturing techniques with the aim of achieving lightweight, flexible, and high performance in the designs. In this section, a structured analysis of the different technologies used in the manufacturing of FPA is presented.
# Exploiting Blockchain Technology for Enhancing Digital Twins' Security and Transparency
## 4 Experimental Results
### Performance Benchmarks  
Although the provided tests for security requirements were essential to ensure the system's reliability, performance measurements were equally crucial in asserting the system's overall usability. The tests' main objective in this paragraph concerned the evaluation of multiple performance metrics regarding the blockchain backbone while providing a reproducible environment for the results shown.  
The provided tests leveraged the benchmarking capabilities of Hyperledger Caliper in order to provide accurate and extensive results on the deployed blockchain network. To achieve the following results, we proceeded by deploying in the digital twin system a self-hosted private blockchain network through docker configuration files as defined in Section 3.1. With the objective of registering performance metrics concerning transactions traveling through the network, we introduced the additional docker container of the Caliper image directly connected to the main network.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Tested Component** & **Possible Threat** & **Recorded Behavior** & **Tested Scenario** \\ \hline \multirow{8}{*}{Manager contract} & \(\bullet\) & Illegal operations & Transaction reverted from the & Updating admin list from an \\  & \(\bullet\) & Data leaks & manager contract & unauthorized address \\  & \(\bullet\) & Digital twin attack & & \\ \cline{2-5}  & \(\bullet\) & Illegal communications & Transaction reverted as not & Sending hash data from an \\  & \(\bullet\) & Digital twin invalidation & registered as a valid path & unauthorized address \\  & \(\bullet\) & System malfunction & & \\ \cline{2-5}  & \(\bullet\) & Information misuse & Authorized actors, but & Invalid communication direction \\  & \(\bullet\) & Data loss & communication reverted & from/to valid addresses \\  & \(\bullet\) & Coherence invalidation & & \\ \hline \multirow{3}{*}{Stub components} & \(\bullet\) & Unauthorized update & Discarded communications & Data sent directly to the digital \\  & \(\bullet\) & Data invalidation & without system interruptions & twin system bypassing \\ \cline{1-1}  & \(\bullet\) & System jamming & & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Summary of security analysis for different components, showcasing potential threats and system responses.  
The whole network was then deployed onto a suitable physical environment consisting of an IMac machine equipped with 10 cores of computational power and 32 GB of RAM and updated to the MacOS Monterey operating system. Full access to all the computational resources described was then granted to the docker network, and it was connected with the external environment through port binding on the host machine. Moreover, the communication network between containers was managed through a local connection on the specified machine to eliminate dependencies on the variable speed of the external network.
# Hybrid ARQ Scheme with Autonomous Retransmission for Multicasting in Wireless Sensor Networks
## 7 Conclusions  
In this paper, a new HARQ scheme with autonomous retransmission was proposed for use in multicast service. By providing a suitable tradeoff between the HARQ gain and the feedback overhead reduction, the proposed algorithm exhibited greater spectral efficiency than the conventional HARQ scheme. As a means to optimize the number of autonomous retransmissions, we introduced a spectral efficiency metric considering both the downlink and uplink, and derived a practical algorithm to adjust the number of autonomous retransmissions. When the importance of the downlink resource is different from that of the uplink resource, the proposed algorithm can be employed with a slight modification of the spectral efficiency metric. The proposed algorithm can be applied to communication standards for wireless multicast services such as SC-PUM of 3 GPP and other future communication standards for WSN.  
This work was supported by the ICT R&D program of MSIP/IITP. [R0126-16-1005, Development of High Reliable Communications and Security SW for Various Unmanned Vehicles].  
[PERSON] designed the conceptual algorithm; [PERSON] developed the practical scheme and analyzed the performance gain; [PERSON] and [PERSON] developed the simulation results; [PERSON] and [PERSON] wrote and revised the paper.  
The authors declare no conflict of interest.
## 4 Implementation Details
### Parallelization
#### 4.2.2 Heterogeneous Parallelization  
The actual empirical Gramians result from \(N^{2}\) inner products. In case of the default Euclidean inner product, this amounts to a dense matrix-matrix-multiplication (Implemented as Generalized Matrix Multiplication (GEMM) \(R=AB+aC\)) by BLAS), which can be efficiently computed by General Purpose Graphics Processing Units (GPGPUs). In the case of an integrated GPU with zero-copy shared memory architecture, such as uniform memory model (UMM) or heterogeneous unified memory access (hUMA) [71], is used, the assembly of the Gramian matrices can be performed with practically no overhead, since the trajectories, which are usually computed and stored in CPU memory space, do not need to be copied between CPU and GPU memory spaces. The GPU can directly operate on the shared memory.
## 1 Introduction
They can also be used for diagnosis and imaging purposes [40, 41, 42]. By using nanocarriers, MTX can be delivered more selectively to the cancer cells, while sparing the healthy cells. This could reduce the dose and frequency of MTX administration and minimise its side effects. Nanotechnology could also help to overcome the resistance that some cancer cells develop to MTX over time. Drug delivery  
Figure 1: Molecular structure of mitoxantrone (MTX) is shown. is an important aspect of cancer therapy, as it can enhance the drug's concentration and activity in the tumour tissue [43]. MOFs have caught much attention recently for potential drug delivery applications [37; 40; 41; 44]. The main objective of this study was to explore the physicochemical aspects, especially the surface properties of UiO-66 and UiO-66-NH\({}_{2}\), as carriers for MTX, with the idea of revealing how the surface characteristics of the MOFs influence drug interactions. MTX loading and drug release profiles were investigated under biologically relevant conditions, elucidating their impact on breast cancer and normal cell toxicity. The results of this study demonstrate that UiO-66-NH\({}_{2}\) (despite presenting a lower loading capacity than UiO-66) presents a slower and more consistent MTX release for prolong duration (maintaining an effective concentration). The slow-release nature of UiO-66-NH\({}_{2}\) might contribute towards reduced cytotoxicity. All this suggests that the presence of amino groups may be responsible to enhance controlled drug release and has the potential to address key challenges related to MTX administration in cancer therapy. Further computational modelling was also conducted, which predicts the interaction between MTX and the MOFs and supports the trend in loading capacity and the slow release observed for UiO-66-NH\({}_{2}\).
# Horizontal Bending Angle Optimization Method for Scraper Conveyor Based on Improved Bat Algorithm
## 3 The Proposed Method
### Flowchart of Optimization Method for Horizontal Bending Angle  
Based on the above analysis, an innovative method based on the improved bat algorithm (MBA) to optimize the horizontal bending angle of the S-bending area of the scraper conveyor is proposed. The flowchart for optimizing horizontal bending angle of S-bending area based on MBA is shown in Figure 4. The optimization steps are summarized as follows:  
Step 2.1: Collect information. Extracting and processing parameter information of fully mechanized mining face.  
Step 2.2: Initialize the parameters of the MBA optimization algorithm and set the number of iterations for the population.  
Step 2.3: Population initialization. Each position of the bat is considered as a horizontal bending angle value, and the fitness value of each bat is the evaluation value of the working surface.  
Step 2.4: Movement speed and position update. The update of the speed and position of each generation of bat population can be obtained according to Equations (8) and (9).  
Step 2.5: Termination condition. When the iteration number t reaches the maximum N, the iteration is stopped, and then the highest score and its corresponding optimal \(\alpha^{\prime}\) value are output; otherwise, Steps 2.2-2.4 are repeated.
# SDN Based Collaborative Scheme for Mitigation of DDoS Attacks
## 1 Introduction
These schemes add functionality in each router to detect and filter attack traffic and also to notify the upstream routers to drop such traffic [13]. As a result, they require more resources at various levels and the push-back mechanism must be deployed in all the participating network components (routers and switches). The complexity and overhead because of the coordination and communication among distributed components adds serious management challenges. SDN based deployments on the other hand ease the management challenges, where a single controller can manage the coordination among all the network components at the AS level. The proposed C-to-C communication protocol is flexible and it can be easily appended with the best known DDoS detection engines. Further, the protocol itself can use different approaches for deployment. It can be deployed in linear order, peer-to-peer or via centralized scheme to collaboratively disseminate DDoS filtering information. In order to assess our proposed collaborative DDoS mitigation scheme, we deploy prototype testbeds in our laboratory. We also introduce three different deployment approaches i.e., linear, central and mesh in our testbed. Scalability and efficiency pose the main challenges because of the number of ASes in the routing systems globally. Our evaluation results are quite promising and demonstrate the effectiveness, flexibility and scalability of the proposed approach. An early version of this work appeared as a workshop paper [14]. In this paper, we have added significant new results with different hop levels. We also demonstrated performance of global dissemination of attack definition with the central deployment approach along with CPU and memory utilization. The rest of the paper is organized as follows. Section 2 describes the state of the art. Section 3 gives the in depth architectural details of our work. In Section 4, we discuss the testbed deployment and evaluations. Finally we conclude the paper in Section 5.
# Optimization of Coverage and Capacity Using Smart Antennae
## 4 Evaluation  
### Experimental Setup  
This research conducted experiments in the parking lot of National Central University, Taiwan, as shown in Figure 6. The area of the parking lot is 250 m by 200 m. The experiment involved 31 base stations (BS) and 39 user equipment (UE) items distributed in the parking lot, as illustrated in Figure 6a,b, respectively.  
The experimental parameters were set as shown in Table 2. The experiment involved placing \(K=39\) signal receivers to simulate users within the NCU parking lot, and conducting trials with \(n=31\) base stations. Each base station comprised \(j=5\) directional antennas. Based on current commercial base station capabilities, the transmission power ranged from \(-19\) dBm to 30 dBm, with an average data transmission rate of 20 Megabits per second.  
The antenna configurations (\(X_{j}^{i}\)) for each direction of \(S_{i}\) and the number of covered UEs are listed in Table 3. This study conducted a small-scale algorithm verification within the experimental environment of the NCU parking lot. For broader areas and a larger user base, experiments were simulated to demonstrate the feasibility of extending the research methodology to other remote mountainous regions.  
\begin{table}
\begin{tabular}{c c} \hline \hline _Area_ & **250 m \(\times\) 200 m** \\ \hline \(n\) & 31 \\ \(j\) & 5 \\ \(P_{max}\) & 19 dBm \\ \(P_{min}\) & \(-30\) dBm \\ \(B\) & 20 Mbps \\ \(K\) & 39 \\ \(\gamma\) & 2 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Parameter settings for simulation.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{\(S_{i}\)} & \multicolumn{4}{c}{\(X_{j}^{i}\)=**1**, _Antenna on:\(X_{j}^{i}\)=0**, _Antenna off_ & **Covered** \\ \cline{2-6}  & \(X_{1}^{i}\) & \(X_{2}^{i}\) & \(X_{3}^{i}\) & \(X_{4}^{i}\) & \(X_{5}^{i}\) & Users \\ \hline \(S_{1}\) & 0 & 0 & 0 & 0 & 0 \\ \(S_{2}\) & 0 & 0 & 0 & 0 & 0 \\ \(S_{3}\) & 0 & 0 & 1 & 1 & 0 & 4 \\ \(S_{4}\) & 0 & 1 & 0 & 0 & 0 & 4 \\ \(S_{5}\) &
## 2 Materials and Methods
### Control System and Experimental Set-Up
#### 2.3.1 Control System  
The control system of the wind-turbine-tower-climbing robot's hardware is shown in Figure 10. The main microcontroller is the Arduino MEGA 2560, which incorporates all the up-down movement controls and carries out the tasks of other electronic modules to harmonize the movement process with the various speeds. This microcontroller controls the four driving wheel motors of the robot, one step motor for the winding mechanism, distance sensor, motor encoder, current sensor, and other support electronic components. It is also considered that, due to its small size, inexpensive cost, reliability, and availability in the market, this microcontroller is good enough for the development of the wind-turbine-tower-climbing robot as it requires a straightforward control procedure and minimum programing code. This study utilized an open-source programming tool called Integrated Development Environment (IDE) to program Arduino boards [26], which supports C-programming code of the wind-turbine-tower-climbing robot, as shown in Figure 11, and then moved to the Arduino board using a USB cable. Its programmable input/output (I/O) pins are configured using C++ programming software, which includes pulse width modulation (PWM) pins and analogue pins. PWM pins can be used to control four DC motors and one step motor, while analogue pins have analogue-to-digital converter (ADC), which can be used to read signals from the distance sensor. The ultrasonic distance sensor--HCSR04 automatically provides feedback signal measurement ranging 200 mm to reach mock-up tower height of 1200 mm to the Arduino microcontroller to attain the precise adhesion in the wind turbine tower mock-up without slipping to the ground. After the distance sensor was able to detect signal the winding mechanism was the next process. With the help of one step motor-42 HS03 with twin pulley attached to its shaft, the Bowden cable, in terms of winding and unwinding, achieves the precise adhesion between the two-body frame in the tower. The step motor slowly winds or rolls-in its cable as it climbs to the tower in an upward movement or unwinds or rolls-out in a downward movement. The support electronics module is needed to run the other devices, such as encoders, while some were required for acquiring data during the entire movement process. A regulated 5 V DC voltage source was needed to power up the Arduino microcontroller and other boards. Once everything was in the right position, the four driving wheels GP-BLDC3650 will push the entire robot in a straight upward and downward movement along the wind turbine tower mock-up. A 12 V DC power supply to the four motors are needed to drive the whole robot.
# Medium Access Control Protocols for Cognitive Radio Ad Hoc Networks: A Survey
## 2 Cognitive Radio Networks
### Cognitive Radio Functions  
Four of the most important CR functions for spectrum control are: spectrum mobility, spectrum sensing, spectrum sharing and spectrum decision [17]. Figure 1 shows the cognitive cycle, and Figure 2 shows the spectrum management process with the functionalities that are discussed in this paper.  
Figure 1: The cognitive cycle.
# Fast Real-Time Data Process Analysis Based on NoSQL for IoT Pavement Quality Management Platform
## 2 Related Works
### IoT Sensing Device  
IoT equipment and devices that can be used for construction site management vary according to their characteristics and purposes. For example, in the case of an image sensor, the image data acquired by the device can be used to monitor the status of the application of a concrete curing agent and to identify defective parts for construction quality management. For asphalt construction management, equipment based on a ground-penetrating radar (GPR) sensor can be utilized for the measurement of asphalt front compaction. For the construction management of cement concrete pavements, smart temperature and humidity sensors are used to manage the condition in real time. Additionally, information necessary for construction site management can be acquired using various IoT sensors such as global navigation satellite system (GNSS) sensors, integrated climate sensors, infrared cameras, acceleration sensors, and gyro sensors.  
Through the use of these IoT sensors, it is possible to automatically manage resources and take immediate action in unexpected situations. Another advantage is that data acquisition and analysis can be performed quickly and accurately. However, there remain disadvantages in that some initial investment costs may be required and that problems with information security and compatibility will have to be addressed.