esa-sceva/satcom-chunk-collection huggingface dataset:
# Thermal Control of CubeSat Electronics Using Thermoelectrics
## 4 Conclusions  
An assessment was presented on the viability of using thermoelectric cooling for the thermal management of on-board electronics on CubeSats. A simple thermoelectric architecture was devised and a set of four empirical models for how such a system would perform were constructed, consisting of linear fits for the total heat dissipated at the hot-side  
Figure 5: Required radiator size that would enable a given thermal resistance, as a function of radiator temperature. The legend shows the radiators’ surface temperature in \({}^{\circ}\)C.  
of the thermoelectric module and the temperature difference (\(\Delta T\)) across the module, as a function of the heat pumped at the cold-side. The model used manufacturers' performance data for a commercially available module. Models were used to calculate the temperature to which the system could cool a CPU, as a function of thermal resistance and heat rejection. As a baseline scenario, the temperature of the system without the thermoelectric module was compared and the benefit, or detriment, of using a thermoelectric module was deduced. Analysis showed that in some circumstances introducing a thermoelectric system would actually increase the temperature of the electronics being cooled. This is most common when the quantity of heat being removed, or the thermal resistance of the system, is high. Nevertheless, thermoelectric cooling is beneficial for a range of conditions, such as when cooling below ambient temperature. However, for the majority of CubeSat orbits, the initial CubeSat temperature is unlikely to be high enough to justify sub-ambient cooling, and the use of thermoelectric cooling for CubeSats may only be applicable in a small number of use cases. Even then, a radiator with low thermal resistance is required. This could undermine the thermoelectric device's potential benefit in many cases, due to imposing the need for an unrealistically large radiator of several square-meters.  
Future work should consider the feasibility of using thermoelectric systems for other space-based environments where the ability to cool below ambient would be of benefit, e.g., on the Moon or Mars, during the day time. Indeed, thermoelectric control has been demonstrated for such scenarios in the past, e.g., for the Mars Curiosity Rover, and further viability assessment of thermoelectric thermal management for rovers of various scales would be worthwhile.  
Conceptualization, N.S.B. and A.C.; methodology, N.S.B.; investigation, N.S.B. and A.H.; writing--original draft preparation, N.S.B.; writing--review and editing, N.S.B., A.H. and A.C. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
Data from the study is available from the corresponding author by request.  
NSB acknowledges the support of UTS's Faculty of Engineering and Information Technology by way of participation in its Professional Experience Program, which allowed the time to carry out this study.  
The authors declare no conflict of interest.
# Chaotic Orthogonal Composite Sequence for 5G NR Time Service Signal Capture Algorithm
## 3 5G NR Time Service Signal Acquisition Algorithm
### Performance Optimization Analysis of Chaotic Orthogonal Combination Sequence  
When comparing the chaotic orthogonal combination sequence with m-sequences, Walsh sequences, Skew Tent-Map chaotic sequences, etc., it is found that the chaotic orthogonal combination sequence has significant advantages in terms of security, correlation and applicability.  
In terms of security, m-sequences are less secure than Walsh sequences under the same number of chips. This is because Walsh sequences are generated from Hadamard matrices. For a register with N bits, m-sequences have \(2^{N}-1\) chips because the Nth bit of the register must be 1, resulting in \(2^{N}-1\) possible constructions. On the other hand, for Walsh sequences, when the number of chips is the same, the order of the Hadamard matrix is \(2^{N}\), and any row or column can generate a Walsh sequence, resulting in \(2^{N}\) possible constructions. Therefore, the security of Walsh sequences surpasses that of m-sequences. The security of the chaotic orthogonal combination sequence, being a combination of Walsh sequences and Skew Tent-Map chaotic sequences, also surpasses that of m-sequences.  
In terms of correlation, the auto-correlation of Walsh sequences is not as prominent as that of m-sequences and Skew Tent-Map chaotic sequences. As shown in Figure 7a-c, respectively, the main peak-to-side peak ratio of Walsh sequences is 2.05, while that for m-sequences it is 13.1, and that for Skew Tent-Map chaotic sequences it is 12.5. As shown in Figure 7d, the main peak-to-side peak ratio of the chaotic orthogonal combination sequence is 11.5, significantly higher than that of Walsh sequences but slightly lower than the main peak-to-side peak ratios of Skew Tent-Map chaotic sequences and m-sequences. This clearly improves the auto-correlation of Walsh sequences.  
Figure 7: _Cont._  
In terms of applicability, Skew Tent-Map chaotic sequences have a fatal flaw: the parameter \(a\) cannot be set to 0.5. Otherwise, these sequence exhibit short-period characteristics, leading to poor auto-correlation, as shown in Figure 8.  
However, when combining Skew Tent-Map chaotic sequences with Walsh sequences to form the chaotic orthogonal combination sequence, even when \(a\) is set to 0.5, although the short-period characteristics of Skew Tent-Map chaotic sequence are retained, the auto-correlation of the chaotic orthogonal combination sequence is still good. As shown in Figure 9, its main peak-to-side peak ratio is 2.17, still slightly better than that of Walsh sequences.  
Figure 8: Short-Period Characteristics of Skew Tent-Map Chaotic Sequences.  
Figure 7: Auto-correlation Plot of Walsh Sequences, m-Sequences, Skew Tent-Map Chaotic Sequences and Chaotic Orthogonal Combination Sequence. (**a**) Walsh Sequences (**b**) m-Sequences (**c**) Skew Tent-Map Chaotic Sequences (**d**) Chaotic Orthogonal Combination Sequence.
# Numerical Modeling of Wave Disturbances in the Process of Ship Movement Control
## 3 Computing Experiments
The first trajectory was obtained at sea state 4 (\(h_{3\%}=1.5,\lambda=60\)) and for the wave angle \(\xi=-\pi/4[\mathrm{rad}]\) (diagonal waves); the second trajectory was produced at sea state 5 (\(h_{3\%}=3,\lambda=90\)) and for the wave angle \(\xi=5\pi/12[\mathrm{rad}]\) (diagonal waves); the third one was also obtained at sea state 5 (\(h_{3\%}=3,\lambda=90\)), but for the wave angle \(\xi=0[\mathrm{rad}]\) (head waves), whereas the fourth was obtained at sea state 6 (\(h_{3\%}=5,\lambda=130\)) and for the wave angle \(\xi=-\pi/5[\mathrm{rad}]\) (diagonal waves). In all four situations, the quality control is high (note the scale used due to the specificity of particular cases), although in the second case the ship is much more pushed to the left (port side, because \(\xi>0\)) than in the first case (to the right--straboard, because \(\xi<0\)), due to higher sea state. In the third case, despite sea state 5, the ship is drifting less than in the second situation, due to the zero angle of the head waves. In the fourth case, the ship has the strongest drift (to the right--straboard, because \(\xi<0\)), due to the highest sea state 6. This happens even if the wave angle in absolute terms is the smallest of all presented situations involving diagonal waves. Figure 5: The trajectory of ship movement and signal of angular speed disturbance \(r_{uv}\) for sea state 5 and the wave angle \(5\pi/12\). Figure 6: The trajectory of ship movement and signal of angular speed disturbance \(r_{uv}\) for sea state 5 and the wave angle 0. Figure 7: The trajectory of ship movement and signal of angular speed disturbance \(r_{uv}\) for sea state 6 and the wave angle \(-\pi/5\). In addition, Figures 4-7 illustrate disturbance signals added to the ship's angular velocity caused by rudder deflection. One can observe that, as expected, the absolute value of the signal increases with increasing sea state, whereas for the steady sea state it decreases for smaller absolute wave angles. The presented situations are typical of the research done. In all examined cases, the model correctly executed hull-affecting disturbances that corresponded to sea waves induced by wind.
# Integrated Optical Phased Arrays for Beam Forming and Steering
## 5 Material Platforms
### III-V/Si Hybrid Platforms  
The Si platform is commonly used to fabricate integrated OPAs. Up to now, the majority of the variable optical phase shifters used on the Si platform are based on TO effects [92]. TO phase shifter-based Si OPAs suffer from limited bandwidths (typically a few kHz) that decrease beam steering speed. High-power consumption and thermal crosstalk limit the integration densities of the OPAs [42]. EO Si phase shifters based on p-n junctions are capable of dense integrations with high operation speeds (tens of GHz) and low power consumption (<2 \(\upmu\)W) [42]. However, the efficiency of the EO Si phase shifters is inherently limited by the free carrier dispersion effect, resulting in high operation voltages or excessive lengths [42]. Modulation effects in III-V/Si phase shifters, such as the quantum-confined Stark effect, band filling, band shrinkage, and the Pockels effect, can be used to increase modulation efficiencies and decrease operating voltages [42; 85]. In addition, the III-V/Si phase shifter with higher electron mobility decreases carrier absorption loss and potentially allows for low residual amplitude modulations and high-speed operations [85]. Furthermore, the heterogeneous III-V/Si integration approaches can potentially realize fully integrated OPA systems [42].  
An integrated OPA with an on-chip laser, amplifiers, and phase modulators was fabricated on the III-V/Si hybrid platform [81]. The OPA with an FOV of 12\({}^{\circ}\) and a beamwidth of 1.8\({}^{\circ}\)\(\times\) 0.6\({}^{\circ}\) was achieved by phase modulations [81]. As illustrated in Figure 11d, an OPA consisted of a star coupler, III-V/Si phase shifters, and WGAs [126]. The 4-\(\upmu\)m-pitch heterogeneous phase shifters in the OPA enabled very low V\({}_{2\uppi}\) of only 0.35-1.4 V across 200 nm, low residual amplitude modulation of only 0.1-0.15 dB for a 2\(\uppi\) phase shift [126]. The first fully integrated 2D OPA on a III-V/Si hybrid platform consisted of 164 integrated components and two steering lasers with different tuning ranges. The OPA with a chip size of 6 \(\times\) 11.5 mm\({}^{2}\) enabled an FOV of 23\({}^{\circ}\)\(\times\) 3.6\({}^{\circ}\) and a beamwidth of 1\({}^{\circ}\)\(\times\) 0.6\({}^{\circ}\)[82]. Another high-performance III-V/Si phase shifter enabled a \(V\uppi\) of 0.45 V and residual amplitude modulation of 0.15 dB at 1.55 \(\upmu\)m. The OPA based on this III-V/Si phase shifter achieved a power consumption of less than 3 nW for a 2\(\uppi\) phase shift and a SMSR of 16 dB [85]. The 32-channel OPA with 4 \(\upmu\)m pitch enabled 2D beam steering with an FOV of 22\({}^{\circ}\)\(\times\) 28\({}^{\circ}\) and a beamwidth of 0.78\({}^{\circ}\)\(\times\) 0.02\({}^{\circ}\)[85]. Another 32-channel OPA with 2-\(\upmu\)m pitch determated an FOV of 51\({}^{\circ}\)\(\times\) 28\({}^{\circ}\)[42].
# Design and Research of Photonic Reservoir Computing for Optical Channel Equalization
## 2 Design of Photonic Reservoir Computing and Verification System
The BER is estimated using the following formula:  
\[BER=\frac{1}{2}[p_{0}\int\limits_{I_{D}}^{+\infty}g_{0}(x)dx+p_{1}\int\limits_{- \infty}^{I_{D}}g_{1}(x)dx] \tag{8}\]  
where \(p_{0}\) and \(p_{1}\) represent the probability of symbols \"0\" and \"1\", respectively. \(I_{D}\) is the judgment threshold. \(g_{0}(\cdot)\) and \(g_{1}(\cdot)\) represent probability density function of symbols \"0\" and \"1\".
## 4 Case-Study Building
### Modal-DBD Design Steps
#### 4.2.3 Definition of Equivalent Mass and Stiffness Matrices  
Through the analysis steps, the calculation procedure presented in [11; 12] was taken into account and applied to the Blockhaus system schematized in Figure 4 (see also Sections 4.2.4-4.2.6). As known, see [11; 12], the conventional modal-DBD procedure consists in the equivalent linearization of the reference non-linear MDOF system object of analysis, based on a reliable values for the story stiffness of a linear elastic MDOF. The latter must be estimated at the target inter-story drift, thus is expected to be strictly related the intrinsic features and flexibility of Blockhaus assemblies (i.e., Table 2). Given that the X- and Y-directions were analyzed separately in this paper, the natural frequencies \(\omega_{N}\) and mode shapes \(\varphi_{N}\) were determined by solving the traditional eigenvalue problem:  
\[\big{[}K-\omega_{N}^{2}M\big{]}\varphi_{jN}=0 \tag{6}\]  
with \(K\) and \(M\) the stiffness and mass matrices.  
Figure 5: Design acceleration response spectra for Eureka (CA, USA), in accordance with [5].  
More in detail, the diagonal mass matrix:  
\[M=m\left[\begin{array}{ccc}1&0&0\\ 0&\beta_{m2}&0\\ 0&0&\beta_{m3}\end{array}\right] \tag{7}\]  
depends on the total lumped mass \(m\) of the first floor and the \(j\)-th floor mass ratios \(\beta_{mj}\) for the upper levels (relative to the first one). The required mass parameters were calculated from the nominal geometries in Figure 4, thus including the inter-story or roof features and the log-walls components. Preliminary calculations resulted in seismic masses of 60 kN, 54.9 kN and 32.0 kN respectively.  
At the same time, the diagonal stiffness matrix in Equation (6) is given by:  
\[K=k\left[\begin{array}{ccc}1+\beta_{k2}&-\beta_{k2}&0\\ -\beta_{k2}&\beta_{k2}+\beta_{k3}&-\beta_{k3}\\ 0&-\beta_{k3}&\beta_{k3}\end{array}\right] \tag{8}\]  
with \(k\) denoting the unknown first-floor stiffness and \(\beta_{kn}\) the relative stiffness values.  
According to the elevation views of Figure 4, the required input stiffness values for the examined Blockhaus building were considered proportional to each log-wall length, net to possible door/window openings (if any). Major calculation outcomes are reported in Section 4.2.10.  
Once estimated \(m\) and \(k\), the natural frequencies \(\omega_{N}\) (rad/sec) and periods \(T_{N}\) (s) for the \(N\)-th mode of vibration were thus calculated as:  
\[\omega_{N}=\alpha_{N}\sqrt{\frac{k}{m}} \tag{9}\]  
Additionally  
\[T_{N}=\frac{2\pi}{\alpha_{N}\sqrt{\frac{k}{m}}}=\frac{\overline{T}}{\alpha_{N}} \tag{10}\]  
respectively, with \(\alpha_{N}\) the corresponding natural frequency parameter.
## 2 Problem Formulation and Preliminaries
: _The state of the system \(x\) is considered available for measurement._  
\[\dot{V}(t) =\frac{T(\delta_{T},V)\cos a(t)-D(a,V)}{m}-g\sin\gamma(t)-\cos \left(\gamma(t)\right)\dot{w}_{x}(t)-\sin\left(\gamma(t)\right)\dot{w}_{h}(t)\]2 Coordinate systems and reference frames for a small fixed-wing UAV. **Assumption 2**. : _The desired trajectory \(y_{d}\) as well as the signal \(\dot{h}_{d}(t)\) are known bounded functions of time._  
**Assumption 3**. : _The external disturbances \(d(t)\) are unknown bounded and piecewise continuous functions of time._  
_Preliminaries on PPC_  
In the PPC framework, the focus is on achieving a specific behavior in terms of the output tracking error performance. This involves ensuring that the error converges to a predetermined residual set with a predefined minimum convergence rate. In the context of the approximation-free approach proposed in [29], the tracking error \(e(t)\) is defined as the difference between the measured output \(y(t)\) and the desired reference trajectory \(y_{d}(t)\). To quantify the desired performance, a performance function \(p(t)\) is chosen, which is expressed as a decaying exponential function with parameters \(p(0)\), \(p_{\infty}\), and \(\lambda\). In particular, \(p_{\infty}\) represents the maximum allowable absolute error at steady state and \(\lambda\) determines the rate of convergence. Thus, the prescribed performance requirement is met if the tracking error \(e(t)\) remains within the performance envelope defined by performance functions \(p(t)\) and \(-p(t)\), respectively, for all \(t\geq 0\) (i.e., \(-p(t)<e(t)<p(t)\), \(\forall t\geq 0\)). Finally, it is important to note that the initial tracking error \(e(0)\) should be accounted for in the performance envelope, satisfying the condition \(p(0)>|e(0)|\) at \(t=0\).
# Evaluation of Three Auditory-Sculptural Qualities Created by an Icosahedral Loudspeaker
## 1 Introduction
In a performance situation, a quarter-circle arrangement of reflectors is often employed to support a robust and detailed spatialization throughout the audience area [27], cf. Figure 1.  
Layers of different, gesturally moving sound beams using a set of signals help overcoming the problem that precise auditory object localization can be specific to the listening position, as experimentally shown for the IKO [25; 27]. This kind of spatialization results in constellations of auditory objects, for which we have found and confirmed distinguishable auditory sculpture categories [25]. In the literature, [PERSON] ([28], p. 145) and [PERSON] [29] describe sound sculptures as physical sculptures processd by the ability to produce sound. In contrast, [PERSON] [30] and [PERSON] [31] describe sound sculptures that use sound as integral element, detached from physical sculpture. We focus on the latter concept by considering auditory sculptures that are arranged by beam-formed air-borne sound and its wall reflections. Moreover, listening experiments with the IKO indicate that sculptural relations are inter-subjectively recognized [25]. In the composition and performance practice using the IKO as an electroacoustic instrument [31], sculptural qualities turned out to more efficiently characterize the various spatial impressions of a listener than the mere knowledge about localization directions and distances would offer. Figure 1: The IKO in a typical concert situation with reflector panels (Studiobünne MUMUTH, Graz). We adopt three qualities from scholarly writings on sculpture, namely, directionality, contour, plasticity [32; 33; 34; 35]. These expressions and definitions for physical solids do not automatically apply to auditory sculptures, but they lead to notions that we adopted for our purposes here by defining  
* _Directionality_ describes the potential of auditory objects in the auditory sculpture to dynamically guide the listeners attention through a room. * _Contour_ describes the degree of dependency of the auditory sculpture's outline (_silhouette_) on the listening position taken and imagined from temporal evolution. * _Plasticity_ describes the degree of depth grading of the spatially layered auditory objects of the auditory sculpture in the room. This paper presents multiple listening experiments that support the three proposed sculptural quality attributes. Section 2 introduces the experimental setups, as well as the sound material and its spatialization on the IKO. The subsequent sections describe the conditions of each experiment and discuss their results. Finally, the concluding Section 6 summarizes the findings.
## 2 Broadband System
### Fixed-Line Broadband System
#### 2.1.4 Fiber Technologies
In the FTTB solution, there is further optical fiber penetration and ONU can be deployed nearer to the users. Then, LANs, cables, or ADSL broadband communication technologies can be used to connect the ONU to the users' homes. Compared with the FTTC solution, FTTB deployment requires more optical fiber. Consequently, the offered additional optical fiber penetration makes it more suitable for integration services. Moreover, in the FTTH solution, ONUs can be deployed right inside the subscribers' offices or homes. This network implementation enables a fully transparent network in which the ONUs are independent of the bandwidth, wavelength, transmission mode, and transmission technology. The advantages aid the FTTH scheme to be an ideal solution for the access networks [143; 144]. Furthermore, the broadband service diffusion study in [145; 146] shows that FTTH subscribers are significantly increasing. Moreover, since 2002, DSL was a widely adopted solution. However, after a peak around 2006, DSL subscribers are decreasing. Subsequently, DSL subscribers were surpassed by FTTH subscribers in 2009. Besides, it has been observed in a similar study on global market outlook report that, DSL is fast losing its importance as the main broadband technology. This is mainly owing to the offered advantages such as better performance, upgradeability for higher-bit rates (scalability), and the passive nature  
Figure 4: A typical FTTx architecture. of the PON system in which there is no need for power supply. It is also due in part to the aggressive manners in which the FTTx scheme is being deployed. Consequently, it is envisaged that the FTTH scheme will become the widely deployed broadband technology for supporting different services [147]. A broad overview of optical access system development is comprehensively presented in [148,149]. The wireless counterparts of the fixed-line broadband system are presented in Section 2.2.
## 3 Numerical Study
### Mesh Discretization and Boundary Conditions  
To model the concrete elements, a 3-dimensional, 8-noded hexahedral element with 3 degrees of freedom in each node (C3D8R) was used. The reinforcements were modelled using a truss element (T3D2) with 3 degrees of freedom in each node. The model geometry was divided into several parts, with simple shapes and less complex geometry to create uniform meshes. Different mesh algorithms were used to try to improve the meshing. The medial axis algorithm was used to produce the swept mesh, as shown in Figure 10. This figure shows the assembly of all of the concrete beam models meshed with a 25 mm element and a 12.5 mm steel plate, bolt, and nut assembly.  
Figure 10 shows the rebar and bolts that were embedded in the concrete in the interactive model while assigning the concrete as the host. Thus, the rotations and translations of the reinforcing bar and bolt elements were equal to those of the host elements surrounding them (i.e., a perfect bond) [46; 47; 48; 49]. The bond between the steel plate and concrete surface was modelled using the two materials' cohesive behavior. The node coupled method was used to model the bolts, whereas the nodes of the steel reinforcing bar and the steel plate were coupled (Figure 2 details this reinforcement). Figure 1 shows the boundary conditions of the simply-supported beam. All beams were subjected to flexural loading after the modelling was completed, and the results of the entire analysis were investigated.