esa-sceva/satcom-chunk-collection huggingface dataset:
# Edge Server Deployment Strategy Based on Queueing Search Meta-Heuristic Algorithm
## 6 Discussion
### Comparison with Other Algorithms  
Compared with traditional heuristic algorithms, such as PSO, GA, and GWO, QSA exhibits faster convergence in fitness function optimization, leading to lower hop counts. However, the computational time of QSA is 1.2 to 6 times longer than that of other algorithms due to its multi-phase search process. While this increases computational cost, it ensures higher-quality solutions, making it particularly suitable for deployment scenarios where solution quality is prioritized over execution speed.
## 1 Introduction  
Presently, the widely used fourth-generation (4G) mobile network, known as long term evolution (LTE), is gradually giving way to the anticipated adoption of the fifth-generation (5G) mobile network, known as new radio (NR). The 3 GPP technical report 38.913 [1] outlines three primary 5G usage scenarios: enhanced mobile broadband (eMBB), ultra-reliable and low-latency communications (URLLC), and massive machine type communications (mMTC). These scenarios promise significant enhancements, including higher transmission speeds (up to 10 Gbps) and ultra-low latency (as low as 1 ms) [1]. These advancements are set to revolutionize mobile communication services and enable innovative applications [1].  
Building on lessons from operational networks like LTE, mobile operators have encountered user grievances related to signal degradation due to coverage issues or channel fading [2]. Thus, a thorough analysis of control channels across various positions of user equipment (UE) within base station coverage areas becomes crucial in devising strategies to mitigate communication losses. Such insights can optimize 5G base station deployment, improving coverage and user services.  
The mobility of UEs within coverage areas introduces dynamic changes in channel conditions, influenced by device movement and the stochastic nature of wireless channels [3]. Consequently, assessing the behavior of control channels, crucial for communication control, as UE positions change, becomes pivotal.  
With these motivations, this study employs MATLAB simulations to evaluate the performance of the physical downlink control channel (PDCCH) in the new 5G cellular communication network. The paper is structured as follows: Section 2 provides a concise overview of the 5G/NR architecture, followed by Section 3 describing the MATLAB system implementation. Simulation results are presented in Section 4, and finally, Section 5 outlines the conclusions.
## 5 Conclusions  
In this study, the effects of the cowl lip angle on the starting performance were investigated for a mixed-compression hypersonic inlet, and the main conclusions are as follows:  
1. Two starting processes exist depending on the cowl lip angle. During the first starting process, the inlet starts when the opened large-scale separation zone is swallowed; in the second type, the opened separation zone enters the internal contraction region to form a closed separation zone, which is then swallowed to realize the start. Inlets with a small lip angle undergo the first type of starting process, whereas those with a large lip angle undergo the second type.
2. For a given ICR, an excessively large or small cowl lip angle leads to a poor starting performance. In other words, there is an optimal lip angle that can minimize the starting Mach number. For the inlet with ICR = 1.9, the inlet with \(\delta=9^{\circ}\) starts at Ma = 4.57, showing the best starting ability.
3. With an increase in ICR, the optimal cowl lip angle gradually decreases, and the starting performance deteriorates. In this work, the effect of the cowl lip angle on the starting performance was numerically studied, the other aerodynamic parameters such as mass flow, total pressure recovery performance, and flow distortion should all be considered in the design of the cowl lip angle.  
Conceptualization, S.X.; investigation, Y.Z.; methodology, S.X.; validation, Y.W.; writing--original draft, Y.Z.; writing--review & editing, Y.W. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Hunan Provincial Innovation Foundation for Postgraduate, grant number CX20200082.  
Not applicable.  
The data that support the findings of this study are available from the corresponding author upon reasonable request.  
The authors declare no conflict of interest.
## 4 Qualitative Findings and Discussion
### Limitations and Future Research  
Firstly, among the five researchers, three focused on user experience research in the field of health design. During the qualitative data analysis, we have to acknowledge that three researchers were influenced by personal beliefs, and preconceived notions and positions, which thereby impacted their assumptions and biases regarding the attitudes of LSAD users to some extent. Their perspectives suggest that, even if LSAD are effective, negative wearing experiences for LSAD users may lead to abandonment, resulting in resource wastage and user frustration and dissatisfaction. The reason for these biases is that they were influenced by individuals in their surroundings who had previously used LSAD, and their evaluations were not favorable. We recognize that this perspective may have a certain bias. Therefore, throughout the entire research process, we introduced inductive coding in the initial stages of the reflexive thematic analysis to reduce the potential impact of this limitation on the research conclusions.  
Secondly, another limitation of this study is that the universal design improvement recommendations for LSAD that we ultimately proposed may be most applicable to the flexible and semi-rigid types. The applicability to rigid LSAD remains to be observed. This is mainly due to financial constraints and other objective reasons that prevented us from recruiting enough rigid LSAD users. Some rigid LSAD may differ in usage and materials from flexible and semi-rigid types, and this type of LSAD is typically employed in real-life situations for severe lower-back pain conditions. Therefore, it is recommended that future research supplement the user experience of rigid LSAD and formulate service policies related to LSAD.  
In order to drive subsequent improvements and developments in LSAD, it is essential to rely on collaborative efforts from researchers with diverse disciplinary backgrounds. Combining the results of our study, there may be insights that inspire professionals in medical engineering and designers in a related field.  
For researchers in fields such as medical engineering:  
Based on our research findings, tension tests for maximum and minimum effective wearing for different types or degrees of lower-back pain could be conducted. For example, researchers could visualize this intuitively on the LSAD through data visualization methods, as shown in Figure 7.  
For designers in related fields:  
The conceptual solutions we propose may not be perfect or the most suitable. Therefore, we suggest considering multiple rounds of design iteration based on these conceptual proposals to generate the optimal solution for mass production. Emphasis should be placed on our proposed LSAD design improvement recommendations, optimizing the LSAD design through concepts such as modular design, biomimicry, and adjustable features.
## 5 Proposed Predictive Maintenance (PdM) Structure Using Internet of Things (IoT)
### The Application  
The findings' report shall be transmitted to the maintenance team member for monitoring and to a remote database for storage and virtual access. Users may access the database from anywhere through computer or mobile application. Through monitoring, the generated reports from the streamed data will be processed and analyzed, the early detected faults shall be triggered, and the user may optimize and act on maintenance plan. The reports shall be in a graphic format for the ease of interpretation.  
When considering the nature of the maintenance works, maintainers keep moving from one place to another, due to different equipment in different locations, and may be out of network coverage. For them to obtain warning information in a timely manner, the proposed system may send a short notification message to their phones for their actions in the case of equipment component critical condition.
## 5 Numerical Results
### Internally Pressurized FGM Pipe under Cyclic Bending Moment
(**a**) Elastic shakedown under \(P_{in}=0.43P_{y}\) and \(T_{in}=1.75T_{y}\); (**b**) plastic shakedown under \(P_{in}=0.65P_{y}\) and \(T_{in}=2.35T_{y}\); (**c**) ratcheting under \(P_{in}=0.75P_{y}\) and \(T_{in}=1.95T_{y}\). Figure 3:4 Cont. The interaction diagram in Figure 13 indicates that using an FGM pipe with the inner surface made up of CS 1026 causes a shift of the curves determining the boundaries between the cyclic plasticity regimes to the lower thermal loading levels. However, the curve that determines the boundary between reversed plasticity and ratcheting domains, is at a higher or lower thermal loading level for the considered pressure range depending on the FGM pipe having the outer rather than the inner surface made up of CS 1026. Moreover, as can be seen from Figure 13, the FGM pipe with the inner surface made from CS 1026 reaches a plastic shakedown condition in correspondence of lower levels of thermal loading, over the whole region \(0<P_{\text{in}}/P_{y}<1\), than the FGM pipe made with the outer surface in pure CS1026. This means that the largest plastic shakedown limit is achieved for FGM pipe with the inner surface made from CS 1026. It is also found that, for FGM pipe with the inner surface made from CS 1026,  
Figure 3:5 Corresponding stress–plastic strain curves in the circumferential direction of FGM tubes with the inner surfaces made of CS 1026 under sustained internal pressure plus cyclic thermal loading for different types of elastic–plastic behaviors. (**a**) Elastic shakedown under \(P_{in}=0.43P_{y}\) and \(T_{in}=1.75T_{y}\); (**b**) plastic shakedown under \(P_{in}=0.65P_{y}\) and \(T_{in}=2.35T_{y}\); (**c**) ratcheting under \(P_{in}=0.75P_{y}\) and \(T_{in}=1.95T_{y}\). Figure 3:6 Bree’s diagram: interaction diagram for internally pressurized FGM cylindrical shell subjected cyclic temperature difference through-thickness for two FGM profiles including the inner and outer surfaces made of CS 1026.  
the curve specifying the boundary between elastic and elastic shakedown, for a normalized internal pressure in the range 0: \(\approx\) 0.7 shows lower thermal loading compared to FGM with outer surface CS 1026, whereas the reverse happens for a normalized internal pressure between 0.7 and 1. It is important to point out that the above results regarding Figures 7 and 13 entail a future need to carry out a parametric study to investigate the effects of the compositional variations between constituent phases on cyclic responses of FGM pipes in order to achieve an optimum design.
# An Improved Single-Epoch Attitude Determination Method for Low-Cost Single-Frequency GNSS Receivers
## 3 CLAMBDA-Search Model  
Low-cost GNSS receivers have unstable and less-qualified pseudorange and carrier observations, in terms of less observation frequency, larger observation noise, and weak phase  
Figure 1: Baselines layout and body coordinate system definition.  
tracking capability. Therefore, the performance of low-cost receivers will face greater challenges when the signal is blocked. In urban environments, the signal block phenomenon occurs frequently, and the correspondent multipath errors are serious. Even if the signals are received by antennas that are very close to each other, and they may still have different observations, the ambiguity fixing success rate of multiple baselines is highly related to the environment. Therefore, this paper will combine the characteristics of vehicle attitude determination, taking into account geometric information, and improve the existing methods in the ambiguity domain and attitude domain, to obtain more reliable results.
# Study on the Improvement of a Collision Avoidance System for Curves
## 2 Curvilinear Coordinate Conversion
### Finding the Closest Point to an Equation of a Curve  
The essence of curvilinear coordinate conversion is to find the point on the curved road model closest to the vehicle. In this paper, this point is called the nearest point. That is, as shown in Figure 1, the closest point \((x_{0}\,y_{0}\ )\) is the point where the vehicle and the curved road model meet vertically.  
The closest point \((x_{0}\,y_{0}\ )\) is derived by using the distance D(x) between the target point \((x_{tr}\,\ y_{tr}\ )\) and the curve model. D(x) is calculated using Equation (2).  
\[\begin{array}{ll}\text{D(x)}&=\sqrt{(x-x_{tr})^{2}+(y-y_{tr})^{2}}\\ &=\sqrt{(x-x_{tr})^{2}+(ax^{3}+bx^{2}+cx+d-y_{tr})^{2}}\end{array} \tag{2}\]  
When D(x) has the lowest value, the vehicle and the curve road model are closest. The point where the derivative of D (x) is zero is calculated by Equation (3). At this time, D (x) has a maximum value or minimum value. In this paper, due to the geometrical characteristics of the road, there is always one minimum value, and the closest point \((x_{tr}\,\ y_{tr}\ )\) is calculated.  
\[D(x)^{\prime}=0 \tag{3}\]  
To find the root of Equation (3), existing studies employed various algorithms, such as the bisection method, the secant method, and [PERSON]'s method. This study used the bisection method, which is the most representative algorithm, to obtain the solution. The bisection method is based on the intermediate value theorem, which states that the root can only be definitely found if an approximate position is given. The algorithm is simple, since iteration is utilized. As an approximate position of the root can be obtained from the global positioning system (GPS) data of the target vehicle, the bisection method can find the root quickly and accurately [13].  
Figure 2 and Table 1 present the root-finding algorithm concept and pseudo code of the bisection method.  
Figure 1: Concept of curvilinear conversion.  
Figure 2: Algorithm of the bisection method.
# Comparative Analytical Study of SCMA Detection Methods for PA Nonlinearity Mitigation
###### Abstract  
Non-orthogonal multiple access (NOMA) has emerged as a promising technology that allows for multiplexing several users over limited time-frequency resources. Among existing NOMA methods, sparse code multiple access (SCMA) is especially attractive; not only for its coding gain using suitable codebook design methodologies, but also for the guarantee of optimal detection using message passing algorithm (MPA). Despite SCMA's benefits, the bit error rate (BER) performance of SCMA systems is known to degrade due to nonlinear power amplifiers at the transmitter. To mitigate this degradation, two types of detectors have recently emerged, namely, the Bussgang-based approaches and the reproducing kernel Hilbert space (RKHS)-based approaches. This paper presents analytical results on the error-floor of the Bussgang-based MPA, and compares it with a universally optimal RKHS-based MPA using random Fourier features (RFF). Although the Bussgang-based MPA is computationally simpler, it attains a higher BER floor compared to its RKHS-based counterpart. This error floor and the BER's performance gap are quantified analytically and validated via computer simulations.  
PA nonlinearity; Bussgang-based approach; SCMA; RKHS +
Footnote †: journal: Sensors
## 5 Tomato Bioactives as Ingredients in Sun Oils for Skin Care
### Lycopene as a Bioactive Agent with Beneficial Effects in the Skin  
Lycopene is the main carotenoid found in tomatoes (_Solanum Lyopersicum_; SL). As an antioxidant agent, it can prevent oxidative damage to DNA and the possible conversion of normal cells to cancer cells through the quenching of simple oxygen and absorption of free radicals. Indeed, in a recent study (2023) on the incorporation of a lycopene extract in an attempt to synthesize a sunscreen with zinc oxide (ZnO) nanoparticles, it was found that lycopene is an excellent non-toxic antioxidant and can play multiple roles. In particular, lycopene could act as a solvent, but also as a reducing agent and a stabilizer, which facilitated the synthesis of ZnO nanoparticles (NPs) [22]. Furthermore, in an attempt to synthesize sunscreen lotion with a tomato extract in a concentration of 1.5% (2017), it was demonstrated that at the end of 28 days, the sunscreen lotion had retained its physical characteristics (unchanged), as observed by organoleptic observation, measurement of viscosity, pH, centrifugation, and freezing of the fluidization, while the SPF index of this lotion had a value of 22.24 [23].  
Lycopene is, as mentioned above, the main antioxidant in tomatoes. It is an anti-carcinogenic carotenoid, which neutralizes free radicals, especially those from oxygen, present under the lipid membrane and skin covering. In particular, it removes lipid radicals, reduces lipid peroxidation, and prevents erythema caused by UV radiation on the skin. It has the ability to remove ROS twice as good as beta-carotene and ten times better than alpha-tocopherol [20; 24]. In topical application, lycopene provides protection against acute damage caused by UVB radiation by inhibiting epidermal ornithine decarboxylase. Thus, it reduces inflammatory reactions and prevents further damage to DNA. Of particular interest is a study performed in human keratinocytes (HaCaT cell line), arguing that depending on the level of photodamage, lycopene may have a corrective function in irradiated cells [23; 25]. However, surprisingly, it enhances skin protection from both short-term effects (e.g., sunburn) and additive effects of sun exposure (e.g., skin cancer) [2; 20; 26; 27]. More specifically, skin protection mechanisms are enhanced in the presence of lycopene, since prostaglandamtions and phospholipids (which are components of the cell membrane) are synthesized. Therefore, the topical application of lycopene appears to be effective in reducing inflammatory infiltration. Studies conducted in mouse ears demonstrated that anthralin-induced swelling and erythema were significantly attenuated by the epidermal application of 0.05% lycopene, compared to a 1 mg/g betamethasone solution [25]. In addition to its moisturizing properties, lycopene antioxidants as nanoemulsion components promote skin suppressed and its ability to protect against UV rays [27].
# Direct Solar Thermal Water-Splitting Using Iron and Iron Oxides at High Temperatures: A Review
## 2 Theoretical Background
#### Kinetic Model  
The mechanisms by which a pure metal or alloy is oxidized at high temperatures require a series of successive steps [27; 41]. The steps are as follows:  
Step (a) adsorption of a gaseous component,  
Step (b) dissociation of the gaseous molecule and transfer of electrons,  
Step (c) nucleation and growth of crystals,  
Step (d) diffusion and transport of cations, anions, and electrons through the oxide layer. Nevertheless, the reaction between a solid (Fe) and a gas (H\({}_{2}\)O\({}_{(\mathrm{g})}\)) corresponds to a heterogeneous reaction wherein the kinetics are totally or partially controlled for the mass-transport process. The product species, generated by convection and diffusion, can be gaseous or insoluble solids [42]. Diffusion and heat transfer intertwine with the chemical kinetics of non-catalytic heterogeneous reactions, with their respective diffusion equations extending to fluidized solids [43]. The reduction of iron oxide with hydrogen or the oxidation of iron with steam are two typical examples of such reactions. These reactions occur under conditions of a highly compacted unreacted solid with limited porosity, where the chemical reaction progresses rapidly while diffusion proceeds relatively slowly [44]. [PERSON] et al. [44] consider that a superficial non-catalytic heterogeneous reaction consists of the following steps (Figure 2):  
Step (a) diffusion of fluid reactants through the fluid film surrounding the solid. Step (b) diffusion of the fluid reagents through the porous solid layer,  
Step (c) adsorption of the fluid reagents on the surface of the solid reagent,  
Step (d) chemical reaction with the solid surface,  
Step (e) desorption of the fluid products from the solid reaction surface,  
Step (f) diffusion of the product far from the reaction surface through the porous surface, the solid media, and the fluid film surrounding the solid. A study by [PERSON] et al. [45]. involved the oxidation of pure Fe at 500 \({}^{\circ}\)C using hydrogen, water vapour, or various mixtures of the two. The oxidation kinetics were compared with models of chemical diffusion and solid-state reactions. The diffusion of volatile iron in the form of Fe(OH)\({}_{2}\) was identified as the rate-controlling step. This diffusion occurred from the metal-oxide interface through the porous oxide of the inner layer and ended with the deposition of Fe\({}_{3}\)O\({}_{4}\) on the crystals of the outer layer, which acted as sinks. The oxidation kinetics occur according to the parabolic law. The expression of the parabolic rate constant (K\({}_{\mathrm{w}}\)) is represented by the following expression:  
\[K_{w}=4.8\cdot 10^{4}\cdot F_{p}\cdot T^{1/2}\cdot\left(\frac{P_{H_{2}O}}{P_{H_{ 2}O}}\right)\cdot e^{-38,900/RT} \tag{8}\]
# Thrust and Pressure Control in a Solid Propulsion System via Reinforcement Learning
## 2 Model and Algorithm
### Reward Function  
#### 2.4.1 Pressure Control Agent's Reward  
The pressure control agent utilizes a reward function to manage the total nozzle opening and stabilize chamber pressure near the command, considering three key aspects, as follows:  
1. Deviation Penalty: When the chamber pressure significantly deviates from the command, a penalty term is applied to promptly correct the pressure. \[R_{Pc\_depiation}=-|P_{ccmd}(t_{n})-P_{c}(t_{n})|\] (9)  
Figure 6: Comparison of output between actual system and identification system.  
2. Synchronization Reward: As the chamber pressure approaches the command, a synchronization reward stabilizes the pressure, preventing rapid oscillations. \[R_{Pc\_synchronization}=-|(P_{c}(t_{n})-P_{c}(t_{n-1}))-(P_{cmd}(t_{n})-P_{cmd}(t_{ n-1}))|\] (10) 3. Steady-State Reward: When the chamber pressure consistently tracks the command, a small reward encourages maintaining this state. \[R_{Pc\_bonus}=1\;if|R_{Pc\_deviation}|<\epsilon_{1}\;and\;\Big{|}R_{Pc\_ synchronization}\Big{|}<\epsilon_{2}\;\;else\;0\] (11)
4. Dynamic Weights: When the pressure deviation is large, the deviation penalty is intensified; when the pressure deviation is small, the synchronization reward is intensified. We aim for the deviation penalty to have at least half of the weight to ensure tracking accuracy. \[K_{Pc}=0.5 tanh(|P_{cmd}(t_{n})-P_{c}(t_{n})|)+0.5\] (12)  
Finally, the pressure control agent's reward function is shown in Equation (13).  
\[R_{Pc}=K_{Pc}R_{Pc\_deviation}+(1-K_{Pc})R_{Pc\_synchronization}+R_{Pc\_bonus} \tag{13}\]