esa-sceva/satcom-chunk-collection huggingface dataset:
# Highly Sensitive SPAD-Based Receiver for Dimming Control in LiFi Networks +
## 4 Multi-Carrier Transmission Schemes with Dimming Control
### Dco-Ofdm
#### 4.1.2 Adaptive SPAD Receivers
Different from the distortion-induced noise where both the time-domain and the frequency-domain noise variances are equal, \(\sigma^{2}_{W_{\rm d}}=\sigma^{2}_{w_{\rm d}}\), the shot noise, \(w_{\rm a}[n]\), is signal dependent, and hence its frequency domain noise variance can be calculated as seen in ([49], Equation (46)). Due to the averaging effect of the FFT operation, the signal-dependent time-domain shot noise becomes signal-independent in the frequency-domain noise. Therefore, both noise terms in the received signal indicated in (44) are uncorrelated with the signal, making the channel model a conventional additive Gaussian noise channel. Note that, in contrast to the original OWC channel model, the equivalent additive Gaussian channel model for OFDM SPAD-based OWC system in (44) is not restricted by the non-negativity condition of the intensity modulation. Hence, the SNR of the received signal can be written as  
\[\Gamma_{\rm DCO}(\xi)=\frac{\eta^{2}_{\rm DCO}\frac{K}{K-2}}{\sigma^{2}_{W_{ \rm d}}+\sigma^{2}_{W_{\rm a}}}, \tag{45}\]  
where the term \((\eta^{2}_{\rm DCO}K)/(K-2)\) refers to the received electrical signal power with \(|\eta_{\rm DCO}|\) and can be used to measure the dimmed signal.The received symbols can be equalized using a single-tap equalizer. After equalization and parallel-to-serial (P/S) mapping, the received QAM signal can be achieved. The QAM demodulation can then be applied, which results in the recovered bit stream followed by BER calculation.
# Combined Optical Fiber Transmission System Based on QNSC and BER-LM
## 2 Integrated Architecture of QNSC and BER-LM
### Key Generation Based on BER-LM  
\[K(n)=\left\{\begin{array}{ll}1,&BER\geq Thr_{upper}\\ 0,&BER<Thr_{lower}\\ x,&others\end{array}\right\} \tag{1}\]  
The key distribution scheme was proposed in an article that obtained channel characteristics by measuring the SNR of the optical fiber channel and generating the consistent key by quantization coding [9]. As shown in Figure 2, [PERSON] and [PERSON] measure the BER of the loopback fiber channel from both ends of the fiber channel. At the same time, the BER of the loopback fiber channel remains unchanged, so [PERSON] and [PERSON] can obtain the same BER curve. Take the BER sampling points in a period of time, calculate the average (\(\delta\)) of the BER sampling value, and calculate the variance (\(\sigma\)) of the BER sampling value. Quantify the BER sampling values according to formula (1), where Thrupper = \(\sigma+\delta\) and Thrlower = \(\sigma-\delta\). When BER is higher than Thrupper, the quantization value is 1; when BER is lower than Thrlower, the quantization value is 0. When BER is between Thrupper and Thrlower, discard the BER sample value, which can improve the consistency of the quantization results.  
Figure 1: A 2 PSK signal encryption procedure with a PSK/QNSC scheme.
# SAM-PAY: A Location-Based Authentication Method for Mobile Environments +
## 2 Related Work
The exploitation of ground components for localization purposes has been explored extensively in the vehicular ad hoc networks (VANETS). For example, CARAVAN [54] describes a system aimed to locate and track a vehicle based on its transmissions during communication with other vehicles or with the road-side infrastructure, in particular with the Road-Side Units (RSU), which are connected to a location server by the wired network. The location server saves all the location information provided by the RSUs and processes the data together with the information from other sources, e.g., vehicle manufacturers, weather information centers, or traffic management centers. The location server also provides an interface for the location-based service providers, while a trusted Registration Authority provides authentication and authorization services to both vehicles and LBS providers. We see in the CARAVAN system some common points with our proposed system (exploitation of ground components for location services) and additional interesting features to be further analyzed for potential integration in SAM-PAY, like the possibility of achieving location privacy (unlinkability) (reviewed and discussed largely also in [55] in mobile environments) between two or more locations of a vehicle, and in our case, of a UT, in the presence of a global adversary. Finally, it is worth mentioning that several patents have been proposed for improving the security of user authentication on devices via multiple factors and location techniques, e.g., [56; 57; 58; 59].
Sensors_**2015**, _15_, 17621-17648; doi:10.3390/s150717621  
_Sensors_  
**ISSN 1424-8220**  
www.mdpi.com/journal/sensors  
_Article_  
**Cross-Layer Service Discovery Mechanism for OLSRv2 Mobile _Ad Hoc_ Networks  
**[PERSON]. [PERSON] and [PERSON] ***  
Department of Telematic Engineering, University Carlos III of Madrid, Avda. de la Universidad 30, 28911 Leganes, Madrid, Spain; E-Mail: [EMAIL_ADDRESS]  
* Author to whom correspondence should be addressed; E-Mail: [EMAIL_ADDRESS];  
Tel.: +34-91-624-8439; Fax: +34-91-624-8748.  
Academic Editor: [PERSON]  
_Received: 3 June 2015 / Accepted: 14 July 2015 / Published: 20 July 2015_  
**Abstract:** Service discovery plays an important role in mobile _ad hoc_ networks (MANETs). The lack of central infrastructure, limited resources and high mobility make service discovery a challenging issue for this kind of network. This article proposes a new service discovery mechanism for discovering and advertising services integrated into the Optimized Link State Routing Protocol Version 2 (OLSRv2). In previous studies, we demonstrated the validity of a similar service discovery mechanism integrated into the previous version of OLSR (OLSRv1). In order to advertise services, we have added a new type-length-value structure (TLV) to the OLSRv2 protocol, called service discovery message (SDM), according to the Generalized MANET Packet/Message Format defined in Request For Comments (RFC) 5444. Each node in the _ad hoc_ network only advertises its own services. The advertisement frequency is a user-configurable parameter, so that it can be modified depending on the user requirements. Each node maintains two service tables, one to store information about its own services and another one to store information about the services it discovers in the network. We present simulation results, that compare our service discovery integrated into OLSRv2 with the one defined for OLSRv1 and with the integration of service discovery in _Ad hoc_ On-demand Distance Vector (AODV) protocol, in terms of service discovery ratio, service latency and network overhead.  
**Keywords:** service discovery; OLSRv2; MANET
# Competition with the Industrial IoT: A Service-Dominant Logic Approach
## 1 Introduction
### IIoT Challenges and Potential Solutions for Coopetition Enabling  
Digitization involves transforming analogue information into digital format, facilitating data processing, storage, and transmission across digital platforms [19]. Building upon this foundation, digitalization expands the scope by integrating Information and Communication Technologies (ICTs) throughout the value chain. This integration challenges enterprises to evolve, adopting digital networks that revolutionize traditional concepts of workspace and resource distribution [20; 21].  
Within digitalization, the term \"Internet of Things\" (IoT) was introduced by [PERSON], initially at Procter & Gamble and subsequently at MIT's Auto-ID Center in 1998 [22]. [PERSON] envisioned a world where \"every object is part of the Internet\", irrespective of the business proposition behind the IoT [23]. This vision has materialized over two decades, with advancements in wireless communication, sensors, and computing power. Today, the IoT encompasses uniquely identifiable objects capable of transmitting data over the Internet autonomously, minimizing or eliminating the need for human intervention [24; 25]. The evolution of the IoT has facilitated the creation of interconnected networks, ushering in innovative service offerings such as remote monitoring and predictive maintenance [15]. These developments underscore the profound impact of digitization and digitalization on shaping the future of technology, enabling businesses to harness the power of the IoT for enhanced efficiency and novel solutions [26].  
The IIoT, an extension of the IoT focusing on industrial applications, aims at elevating manufacturing SMEs to new efficiency levels through innovative, interconnected industrial systems [5; 27]. These systems facilitate global connectivity and ensure meaningful communication between devices, paving the way for intelligent artefacts that respond to user interactions and contribute to complex value creation processes [28].  
The IIoT represents a non-stop state-of-the-art updating, incorporating new improvements continuously and increasingly embedding the capability to take collaborative actions without humans [22], leading to a hyper-connected society and an increasingly global economy [29]. These collaborative capabilities [25] make IIoT technologies crucial to linking the shop floor directly with customers, enabling modern networks [30]. In technology-enabled networks, these collaborative actions happen not only among machines but also between providers and customers [5] and among rivals (coopetitors), from which value creation is created by multiple actors and determined by the beneficiary, thus converging to S-D Logic foundations [31].
## 3 Energy Efficient Routing  
### Principles  
EOLSR, is the energy efficient extension of OLSR. Like OLSR, it consists of two main functionalities: neighborhood discovery achieved by exchanging _Hello_ messages between one-hop nodes and topology dissemination achieved by broadcasting _TC_ messages advertising preferred links throughout the network. EOLSR maximizes the network lifetime by:  
* Minimizing the energy consumed by a packet transmission from its source to its destination. The transmission and reception is a source of energy consumption, and optimizing their number could optimize the energy consumption.
* Balancing load between nodes and avoiding nodes with a low residual energy. Using the same nodes to route messages exhausts the batteries of these nodes. As a consequence, they will fail more quickly than others. This could lead to network partitioning or some application functionalities are no longer assured (e.g. a zone is no more monitored).
* Reducing the overhead.  
EOLSR uses an energy consumption model to take its routing decision. As MPRs (MultiPoint Relays) are the intermediate nodes on routes, the selection of MPRs must take energy into account as well as the selection of routes. To save energy, network broadcasts should be optimized. That is why, EOLSR consists of the four following modules [3]:
## 3 Results and Discussion  
### Effects of Different Extraction Conditions on the Yield of PSP  
#### 3.1.1 Extraction Time  
As shown in Figure 1a, the effect of time (ranging from 20 to 60 min) on the extraction yield was investigated when other parameters were as follows: Enzyme concentration 2.5%, temperature 60 \({}^{\circ}\)C, and pH 6.0. Result indicated that the yield of PSP reached the maximum when extraction time was 40 min. It is reported that under a long extraction time and high temperature, the hydrolysis of polysaccharides would happen [20]. Therefore, 40 min was a suitable extraction time for the EAE.
# Investigation of Electro-Elastic Properties for LN Single Crystals at Low Temperature
## 3 Results and Discussion  
### Temperature Dependence of Dielectric Permittivity  
The variation of relative dielectric permittivities \(\left(\Delta E_{\mathrm{ii}}^{T}/\varepsilon_{0}\right)/\left(\varepsilon_{ \mathrm{ii}}^{T_{0}}/\varepsilon_{0}\right)\) (\(\Delta E_{\mathrm{ii}}^{T}/\varepsilon_{0}=\varepsilon_{\mathrm{ii}}^{T}/ \varepsilon_{0}-\varepsilon_{\mathrm{ii}}^{T_{0}}/\varepsilon_{0}\), \(i=1\), \(3\), and \(T_{0}=150\)\({}^{\circ}\)C) as a function of temperature from \(-150\)\({}^{\circ}\)C to \(150\)\({}^{\circ}\)C were studied for LN crystals, as illustrated in Figure 2. The relative dielectric permittivities \(\varepsilon_{\mathrm{1}}^{T}/\varepsilon_{0}\) and \(\varepsilon_{\mathrm{3}}^{T}/\varepsilon_{0}\) were \(83.2\) and \(29.4\) at room temperature, respectively. The \(\varepsilon_{\mathrm{1}}^{T}/\varepsilon_{0}\) and \(\varepsilon_{\mathrm{3}}^{T}/\varepsilon_{0}\) were \(78.0\) and \(26.3\) at \(-150\)\({}^{\circ}\)C, and then increased to \(88.1\) and \(33.2\) at \(150\)\({}^{\circ}\)C, showing positive temperature variations. The dielectric losses for LN crystals along the X- and Z-axes were lower, and the variations were smaller over the measured temperature range.  
Figure 1: Schematic configuration for the evaluation of electro-elastic constants: (**a**) X-square plate; (**b**) Z-square plate; (**c**) Z bar; (**d**) YX plate; (**e**) ZY plate; (**f**) ZX plate; (**g**) YZI/\(\theta\) (\(\theta=30^{\circ}\), \(45^{\circ}\) and \(60^{\circ}\)); (**h**) XYt/\(\theta\) (\(\theta=60^{\circ}\)); and (**i**) ZXt/\(\theta\) (\(\theta=70^{\circ}\) and \(80^{\circ}\)).  
Figure 2: Variation of relative dielectric permittivity and dielectric loss for LN crystals.
## 1 Introduction
Along this line, our proposal aims to increase the capacity of SSB by compensating ISI in uncodec and codec system using turbo codes, given that turbo code is considered as a potential channel coding scheme for 5G radio specification within Verizon's 5G Technology Forum (V5 GTF) [15]. Overall, in this paper, we propose a new modulation communication scheme using 4-SSB over modulated techniques including OFDM and MIMO to improve the channel capacity and data rate of the communication systems towards 5G. To achieve this goal, we develop a shadow minimum mean square error (MMSE) equalizer for the 4-SSB modulated systems to diminish the system complexity. We then verify the system design under both uncoded and coded environments using turbo codes following the 5G specification document as a practical contribution toward feasible massive MIMO (m-MIMO) system implementation. Typically, we investigate and propose an enhanced mobile broadband scheme by addressing the challenging requirements in 5G through potential architectural design including the application in m-MIMO and new modulation spectrum for highly efficient communications with low cost and low complexity at the same time.
## 4 Results and Discussion
### Influence of Azimuth Radial Angle and Tangential Angle on Tracking Performance of an SDC System  
In this section, taking a typical day (the summer solstice) in a typical area (Dunhuang) as an example, the influence of the radial and tangential angles of the azimuth axis on the tracking performance of an SDC system is studied. Figure 5 shows the variation of effective tracking factor of an SDC system with the azimuth axis radial angle \(\theta_{1}=0.05^{\circ}\), \(0.1^{\circ}\), \(0.15^{\circ}\), \(0.2^{\circ}\), and \(0.25^{\circ}\) and the tangential angle \(\phi_{1}=[0^{\circ},\,360^{\circ}]\). When the tangential angle of azimuth axis is constant, with the increase of the radial angle of azimuth axis, the effective tracking factor decreases, that is, the tracking performance of the SDC system decreases. When the radial angle of azimuth axis is constant, with the tangential angle of azimuth axis changing from \(\phi_{1}=0^{\circ}\) (due south) to \(\phi_{1}=180^{\circ}\) (due north), the effective tracking factor first decreases and then increases. When the azimuth tangential angle of azimuth axis is \(\phi_{1}=0^{\circ}\) and \(\phi_{1}=90^{\circ}\), the effective tracking factor reaches the maximum and minimum, respectively. That is, when the azimuth axis's tangential angle is \(\phi_{1}=0^{\circ}\) or \(180^{\circ}\), the tilt error of the azimuth axis has the least influence on the tracking performance of the SDC system. At the same time, we find that the change of the azimuth axis radial angle has the same trend for the tracking performance of the SDC system. Two azimuth axis tangential angles symmetrical about the origin have the same tracking performance. For example, when the azimuth axis tangential angles are \(\phi_{1}=0^{\circ}\) and \(\phi_{1}=180^{\circ}\), the tracking performance is the same. In the subsequent study, in order to reduce the amount of calculation, we used the radial angle \(\theta_{1}=0.1^{\circ}\) and the tangential angle \(\phi_{1}=[0^{\circ},360^{\circ}]\) of azimuth axis.
# Low-Cost Software Evaluation of Communication Delays in Networked Industrial Systems
## 3 Measurement System Architecture
### Base Architecture  
Figure 1 depicts the system architecture, where \(TM\) is the test manager acting as sender \(S\) and receiver \(R\). \(TM\) runs suitable software tools to generate the needed traffic, send it through port \(n_{S}\), and then analyze packets received through port \(n_{R}\).  
Figure 1: Architecture of the measurement system.  
For example, in the case of the testbed implemented in our laboratory, all ports belong to the same PCI Express StarTech(r) ST4000 SPEXI 4-Port Gigabit Ethernet Network Card, [29] based on theIntel Corporation(r), Santa Clara (CA), USA, I350 quad-port Ethernet controller [30]. The card is manufactured by StarTech.com Ltd., London (ON), Canada. As detailed in Section 4.1, the I350 is able to accurately timestamp incoming and, with some limitations, outgoing packets. Moreover, our _TM_ is based on an Intel Pentium CPU G870 @3.10 Ghz and runs Linux Ubuntu 20.04.3 LTS as operating system.  
All ports are isolated from each other by means of the Linux Namespace functionality to ensure that each port is managed by its own logical instance of the TCP/IP protocol stack. In turn, this guarantees that packets flow from one port to another in the intended way, preventing any route optimization that might be put into effect, when all ports are managed by the same protocol stack instance.  
In Figure 1, _TAP_ is a network tap which duplicates packets outgoing from \(n_{S}\) in order to return them back to _TM_ through the monitoring port \(n_{M}\). The purpose of _TAP_ is addressed in more detail in Section 4.2, which discusses common shortcomings in packet timestamping and how to manage them.  
The _SW_ configuration determines the actual path of packets from \(n_{S}\) to \(n_{R}\). These connection paths can be easily configured and changed with the aid of two port-based VLANs. \(DUT_{1}\) and \(DUT_{2}\) in Figure 1 are the devices under test.
## 3 Multi-View Modeling
### Model Implementation
When the overlap satisfies \(O_{\text{threshold}}\), the index \(j\) of the current bounding box is appended to the suppressed bounding box set \(S\). Then, it must be determined whether the overlap is larger than \(O_{\text{max}}\). When the overlap is larger, \(O_{\text{max}}\) is updated, and the area \(A[j]\) of the current bounding box \(B[j]\) is compared with the area \(A[i]\) of the bounding box \(B[i]\). When \(A[i]\leq A[j]\), the last index \(i\) in \(P\) is removed, and the index \(j\) is appended to \(P\). At the end of the current iteration, \(S\) is removed from \(I\). Then, the next iteration begins. This process is repeated until \(I\) is empty. Finally, the final object index set \(P\) is obtained after the region merging operation. Then, according to the mapping relationship between \(P\) and \(B\), the set \(B_{\text{RM}}\) of the selected object boxes after region merging is fetched from \(B\). The details of the entire process are shown in Algorithm 1. ```
1:Input: Candidate bounding box set \(B\) from stage one
2:Output: Region-merged object box set \(B_{\text{RM}}\)
3: Initialize the region-merged object box set \(B_{\text{RM}}\), the index set \(P\) of \(B_{\text{RM}}\), overlap threshold \(O_{\text{threshold}}\), overlap maximum \(O_{\text{max}}\), \(P=\varnothing\), \(B_{\text{RM}}=\varnothing\), \(O_{\text{threshold}}=t(t<1)\), \(O_{\text{max}}=0\)
4: Obtain the set of the indexes \(I\) according to the order of candidate bounding boxes sorted by the coordinate \(y_{2}\)
5:While \(I\) is not null do
6: Obtain the last index \(i\) of \(I\): \(i=I[last]\)
7: Set the suppressing bounding box set \(S=[last]\)
8: Append the last index \(i\) to \(P\): \(P=P\cup i\)
9:Foreach index \(n\) in \(I\)do
10:\(j=I[n]\)
11: Calculate the overlap \(O(B[i],B[j])\) using the theory of IoU
12:If \(O(B[i],B[j])>O_{\text{threshold}}\)do
13: Append the index n to the set \(S\): \(S=S\cup n\)
14:If \(O(B[i],B[j])>O_{\text{max}}\)do
15:\(O_{\text{max}}=O(B[i],B[j])\)
16: Calculate the area \(A[i]\) of \(B[i]\) and the area \(A[j]\) of \(B[j]\)
17:If \(A[i]\leq A[j]\) do
18: Remove the last index \(p_{last}\) in \(P\): \(P=P\backslash p_{last}\)
19: Append the index \(j\) to \(P\): \(P=P\cup j\)
20: Remove the suppressing bounding box set \(S\) in \(I\): \(I=I\backslash S\)
21:Foreach \(p\) in \(P\)do
22: Extract the object bounding boxes \(B_{\text{RM}}\): \(B_{\text{RM}}=B_{\text{RM}}\cup B[p]\)
```  
**Algorithm 1** RM (Region merging)
## 6 Conclusions  
The research objective to reveal the effect of the Daubechies wavelet basis function (DWBF) and the decomposition level has been achieved. The details of the experiment results can be seen in Section 3. The results show that choosing the right decomposition level is very important in order to get the optimal performance of atrial fibrillation detection. On the other hand, the selection of the DWBF order has less impact on AF detection performance. Furthermore, the highest accuracy result is achieved in DB\({}_{2}\)DL\({}_{4}\), which is 94.17%, while the highest sensitivity and specificity are obtained in DB\({}_{6}\)DL\({}_{2}\) and DB\({}_{2}\)DL\({}_{4}\), i.e., 97.57% and 96.75%, respectively.
## 3 Minimum Transmission Range to \(2\)-Cover a Path on a Polygonal Region
### Decision Problem
Deciding if a \(2\)-path between points \(p\) and \(q\) exists takes \(\mathcal{O}(k\times nM)\) time if \(\mathrm{VD}_{2}(S)\) has been previously built._  
**Proof**: Decomposing region \(R\) with \(m\) vertices in convex pieces by adding a set \(L\) of \(k\) rays takes \(\mathcal{O}(m+k^{2}\log(\frac{m}{k}))\) time [16]. Consequently, \(R\) is decomposed in \(k+1\) convex pieces. Supposing each convex piece \(R_{i}\) has \(m_{i}\) vertices, let \(M=\max\{m_{1},\ldots,m_{k+1}\}\). According to Theorem 2, constructing \(G_{i}\) for each convex piece takes \(\mathcal{O}(nm_{i})\) time, so constructing a first version of \(G\) takes \(\mathcal{O}(k\times nM)\) time. For the same reason, constructing arrangement \(A\) also takes \(\mathcal{O}(k\times nM)\) time. Studying the vertices of every face of \(A\) on a convex piece takes \(\mathcal{O}(nM)\) time. Consequently, finding the sets of faces which have an edge on the same ray of \(L\) takes \(\mathcal{O}(k\times nM)\) time. Computing the lens that contains a face of \(A\) can be done in constant time. Every ray of \(L\) can intersect \(n\) Voronoi regions and so \(n\) faces of \(A\). Therefore, each set of faces \(F_{i}\) has cardinality at most \(n\). The vertices of the rays of \(L\) can have degree \(3\) at most [16], so the number of nodes of \(G\) to be merged at a time is at most \(3\), which can be done in constant time. Consequently, the construction of \(G\) is concluded in \(\mathcal{O}(kn)\) time. Locating \(p\) and \(q\) on \(A\) can be done in \(\mathcal{O}(nM)\) time. In the worst case, the Depth-First Search algorithm has to visit every node of \(G\) twice [18]. Therefore, traversing \(G\) to decide if there is a \(2\)-path between points \(p\) and \(q\) takes \(\mathcal{O}(kn)\) time. Overall, this decision problem can be solved in \(\mathcal{O}(k\times nM)\) time. Note that if \(R\) is a convex polygonal region with \(m\) vertices, then deciding if a \(2\)-path between points \(p\) and \(q\) exists takes \(\mathcal{O}(nm)\) time if \(\mathrm{VD}_{2}(S)\) has been previously built (Theorem 2). It suffices to compute the arrangement and the corresponding graph just for one convex piece.