esa-sceva/satcom-chunk-collection huggingface dataset:
# On the Analysis of Coverage Feedback in a Fuzzing Proprietary System
## 3 Materials and Methods
### Modification to libFuzzer for the Experiment  
We modify and prepare three versions of the Clang compiler for the experiment: (i) the no-coverage version, (ii) the partial coverage version, and (iii) the full coverage version (the original one). Modifying to totally exclude code coverage feedback in libFuzzer's implementation (for the no-coverage version) seems to be a simple task; however, there are a few things to consider. For example, simply ignoring the coverage feedback information for deciding whether to keep or discard the mutated input raises some problems. If we always choose to keep the mutated input by skipping the coverage feedback operations, the corpus set will continuously increase over time, thus quickly exhausting disk/memory space and slowing down the entire fuzzer's performance until it crashes due to an out-of-memory error. Thus, this decision is improper for our experiment design. Also, we need to be careful of compiler optimization erasing important instructions unrelated to coverage feedback. Our modified libFuzzer performs input mutation but always discards the test case after finishing each execution, which is a simple standard implementation in non-coverage feedback fuzzers. Figure 2 shows the relevant code patch (we mainly modified the RunOne() function of libFuzzer to only exclude the coverage feedback during the source code modification. We checked the recompiled fuzzer binary considering the possibility of compiler optimization erasing important features other than the feedback). And the result of the modified libFuzzer binary was used to ignore the feedback. Additionally, we note that the no-coverage version of our libFuzzer does not eliminate the existing code for measuring code coverage in the fuzzing round. Instead, the modified version ignores the inspected coverage information and processes every input as if it does not increase the overall coverage. Because of this, the execution time of a single fuzzing round for both the original fuzzer and the altered fuzzer would not exhibit a measurable difference in timing performance. However, when a fuzzer discovers new coverage, it stores the in-memory test data to external storage (disk), which involves a significant timing delay. Unfortunately, predicting the pattern and occurrence of such delays is challenging, so we use the execution counts of the fuzzer as a comparison metric in our evaluation.  
Figure 2: The key patch for libFuzzer to optionally discard coverage feedback. We modified RunOne and its dependent code appropriately, considering compiler optimization, and confirmed the resulting binary to double-check correctness.  
In case of partially excluding coverage feedback, we need to investigate the detailed implementation of the libFuzzer coverage feedback engine. In our customization, we gather partial coverage by changing the _granularity_ of the coverage measurement rather than selectively keeping/discarding the coverage information. To explain this in detail, we first need to discuss details of libFuzzer's coverage measuring system.
# Multi-Region OpenFOAM Solver Development for Compact Toroid Transport in Drift Tube
## 4 Numerical Simulation of CT Magnetohydrodynamics
### Geometric Structure and Simulation Parameter Settings
In Cases 3 and 4, the inner surface of the finite resistive wall is set to zero-gradient conditions for temperature and pressure and slip conditions for velocity, and the magnetic flux density uses the custom internal coupling boundary condition mentioned in Section 2. The outer surface of the finite conductive wall is set to fixed zero magnetic field. Moreover, since the CT satisfies toroidal symmetry, all four cases adopt OpenFOAM's built-in wedge boundary condition (for solving axisymmetric problems), reducing the 3D problem to 2D r-z plane simulation. The maximum grid size is 4 mm.
## 3 Results and Discussion
### Soil Enzyme Activity  
For the S-UE activity, no significant impact was found across all the CuO NP treatments in terms of use doses and particle sizes, except the 50 nm CuO NP treatments, where the S-UE activity was significantly reduced by 15.5% at 1 mg/kg and increased by 10.9% at 10 mg/kg, as compared to the control (Figure 5A). Soil urease can catalyze the hydrolysis of urea into NH\({}_{3}\) and CO\({}_{2}\) in the soil [44]; thus, the activity of S-UE determines the amount of NH\({}_{3}\) that can be taken up and utilized by plants [45]. The decreases in the S-UE activity in the CuO NP treatments might be the reason that the NO\({}_{3}\)\({}^{-}\)-N contents were reduced in roots. The pattern of the changes in the S-NP activities as a function of CuO NPs was similar to the NO\({}_{3}\)\({}^{-}\)-N content in roots (Figure 2B). At 10 mg/kg, the 20 nm CuO NP treatments reduced the S-NP activity by 54.4%, while the 50 nm CuO NP treatment with 1 mg/kg reduced the S-NP activity by 35% relative to the control (Figure 5B). S-NP activity was positively correlated with soil N content and can affect the availability of P in the soil directly [46].  
At both use doses, the 20 nm CuO NP treatments increased the S-PPO activity by 18.2% and 98%, while the 50 nm CuO NP treatments increased its activity by 103% and 100%, respectively, relative to the control (Figure 5C). Excess amounts of NO\({}_{3}\)\({}^{-}\) and NH\({}_{4}\)\({}^{+}\) in the soil could inhibit the activities of fungi, which secrete polyphenol oxidase [47]; thus, the increased S-PPO activities might be caused by the increased uptake of NO\({}_{3}\)\({}^{-}\) and NH\({}_{4}\)\({}^{+}\) by roots as a function of CuO NPs. The increase in S-PPO activities could provide more energy for soil microorganisms, which was conducive to the increase of microbial biomass carbon [48]. For the S-SC activity, no significant impact was found across all the CuO NP treatments in terms of use doses and particle sizes, except the 20 nm CuO NP treatments, where the S-SC activity was significantly reduced by 23% relative to the control (Figure 5D).  
Figure 4: Amino acid content (**A,B**) and protein content (**C,D**) in soybean shoots and roots in the 20 and 50 nm CuO NP treatments at 1 and 10 mg/kg for three weeks. Error bars represent the standard error of 5 replicates, and the different letters in each panel represent significantly different values at \(p<0.05\).
# Sigma Routing Metric for RPL Protocol
## 6 Results
### Energy Consumption  
In order to estimate the energy consumption with precision, the percentage of radius over time was used, since the radius depends on the current consumption in the sensor nodes.  
As shown in Figure 15, when the network is small, because of complex calculations, SIGMA-ETX can consume more energy, but when the network expands, SIGMA-ETX can maintain better connections than PH-ETX, making total consumption lower. Regarding energy consumption, results show OF0 reaches 51.11% of SIGMA-ETXs results, MRHOF reaches 74.19%, and PH-ETX reaches 85.19%.  
Figure 14: Packet delivery ratio.  
Figure 15: Energy consumption.
## 3 Secure FSO Link in GNU Radio Simulation
### Initialisation  
Before any communication can occur, the initial setup must take place; this includes setting variables in GNU Radio for system parameters, as illustrated in Figure 3. There are also QT graphical user interface (GUI) blocks that control the user interface (UI) elements of the flowgraph. The QT GUI Range blocks allow the user to change the value of certain aspects of the FSO link using a slider and the QT GUI Tab widgets allow the user to switch between tabs for different system performance views.  
Figure 2: System block diagram.  
At this stage, the encryption keys are generated: one pair for each transmitter and receiver. The Generate Keypair block uses a NaCl function called crypto_box_keypair to generate a 32-byte secret key and a corresponding 32-byte public key. These random keys are generated using the Curve25519 function in NaCl which is a high-speed key generation method resulting in smaller keys than other cryptography methods such as RSA. The function first generates a random 32-byte integer which is considered to be a private key, then computes a corresponding public key. The properties of elliptic curves are used to combine a base point with the random private key to produce the public key. Here, the curve used in Curve15519 is always defined as \(y^{2}=x^{3}+486662x^{2}+x\). This public key is created so that it is impossible to decipher the private key from the public key and base point without considerable computational effort.  
For encryption to occur, the sender must have the recipient's public key and vice versa. Therefore, the system becomes more secure as an attacker needs to know both the sender and recipient's public keys, which means the public keys can be exchanged across an insecure channel. In the case of this simulation, it is important to point out that this key exchange is assumed to have already taken place because the keys are stored on the same local drive. In the real world, the keys would have to be generated and then the public keys need to be exchanged for any secure communication to occur.
## 1 Introduction
There are two primary means of estimating the effective average dielectric properties:  
* estimating from signals that have propagated through the imaging domain;
* and via parameter search based on properties of the reconstructed images. Estimation from time-of-flight assumes that the properties of the chosen paths are representative of the volume as a whole. In contrast, parameter search algorithms assume that the properties of images with incorrectly estimated effective average dielectric properties are different to those of correctly focused images. Algorithms based on parameter search are useful because they are largely independent of the imaging hardware and configuration, and are not susceptible to multipath propagation within the imaging domain. Two main metrics for parameter search have been proposed for microwave imaging for both stroke and breast cancer detection based on  
* maximising the response in a 4 cm\({}^{2}\) area while minimising the energy outside this region [38; 39];
* or rewarding images with one strong response and penalising other large or strong responses [14; 40]. Based on the properties of incorrectly estimated images observed from point spread functions (PSFs), focal quality metrics (FQMs) are proposed as suitable and effective fitness functions that can be used in parameter search algorithms for estimating the average dielectric properties. Twenty-three commonly used FQMs are investigated. FQMs are commonly used in microscopy and digital photography for focal length optimisation [41]. FQMs have been identified as potential fitness functions for parameter search algorithms in simplified, numerical simulations using ideal artefact removal algorithms [42; 43; 44]. This work analyses FQMs in more realistic experimental test cases, using a practical artefact removal algorithm and diverse heterogeneous phantom set with between 10 and 40% fibroglandular structures by volume. This allows the parameter search algorithm to be tested in the presence of experimental noise and hardware artefacts. Additionally, a parameter search algorithm is applied to the full three-dimensional images, unlike the two-dimensional images analysed in [44]. The rest of this paper is structured as follows: Section 2 describes the parameter search algorithm in detail and how the properties of high quality images are determined; Section 3 describes common FQMs used in focusing and analysed in detail in this work and Section 4 describes the experimental setup used to validate the algorithms. Section 5 shows the results of the theoretical analysis and experimental validation; and Section 6 concludes the paper, identifying suitable FQMs for the estimation of average dielectric properties.
# Analysis of New Orthogonal Transforms for Digital Watermarking
## 4 Experimental Results
### Transform Preprocessing  
In order to provide satisfactory results as far as both high imperceptibility and low error rate in the recovery phase are concerned, each matrix applied for forward and inverse transform operations had to be initially preprocessed. Upon creation of the matrix according to the standard procedure described in Section 4.2, all its elements are divided by the sum of all elements from the first row of the matrix. This results in all matrix elements belonging to the range: \(<-1,1>\). In this way, when calculating the spectrum of an image, all the spectral coefficients will not reach high values, which will prevent the embedded bits from being lost while saving the image upon inverse transform operation. This transform preprocessing is mainly focused on the assurance that the whole message hidden in an image will be fully recoverable.
# Towards the Development of Agenda 2063 Geo-Portal to Support Sustainable Development in Africa
## 3 Geoportal Implementation Framework
### Hardware Infrastructure  
The pilot geoportal application was deployed on a development server with 300 GB storage capacity, 32 GB memory, 2 processor sockets, each with 16 cores. A storage server with over 30 TB of storage space was mounted on the deployed server for storing the large continental base layer datasets.
# Entropy Weighted TOPSIS Based Cluster Head Selection in Wireless Sensor Networks under Uncertainty
## 6 Concluding Remarks  
The MCDM method for cluster head selection in WSNs under uncertainty has been examined in this paper. TOPSIS, an entropy-based technique, is used to choose the CHs in WSNs. The number of clusters/cluster heads is optimized by considering six parameters: reliability, residual energy, the number of neighbor nodes, the distance from the sink (BS), the average distance of non-cluster nodes, and the distance ratio. We employed Triangular Fuzzy Numbers to express all the characteristics, including initial node energy, the distance between sensor nodes and base stations, the size of data packets, voltage, and transmission energy measurements, and other matters about sensor nodes (TFNs). For the context of this research, we segregated the entire network into 14 clusters, with a cluster head in each cluster, based on our hypotheses. For this experiment, we used the NSG2.1 simulator and tool command language. We also used the AODV protocol for simulation. The nodes in this network topology were generated using a uniform distribution, and a technique for choosing cluster heads was also proposed. The lifespan achieved by the LEACH protocol was compared to the lifetime achieved by the simulated network. Simulation results show that our suggested approach, based on the entropy-weighted TOPSIS method, significantly extends network lifetime and saves energy compared to the LEACH protocol. Finally, the overall strategy used in this work will serve well enough for the selection of cluster heads as well as other network design aspects associated with WSNs, including uncertain parameters.  
[PERSON], [PERSON], [PERSON] and [PERSON] formulated and studied the problem. [PERSON], [PERSON], [PERSON] and [PERSON] wrote the first draft of the manuscript. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The authors are grateful to anonymous referees for their constructive as well as helpful suggestions and comments to revise the paper in the present form.  
The authors declare no conflict of interest.
## 3 Results
### Hip  
#### 3.1.1 Microstructure  
The metallographic preparation of the samples was divided into the following steps: grinding with SiC abrasive paper of various grit sizes, polishing with diamond paste of various grit sizes, and recording of the microstructural images using a Leica DM6M microscope. The pure Al was etched four times for 30 s with Barker after polishing, and then the microstructure was recorded with polarised light. The unetched microstructure of the Al-particle composite was visualised using bright field microscopy. A nearly homogeneous, globular grain structure could be created in the pure Al by HIP, see Figure 6a. The magnetic particles Co, Ni, and Fe could be implemented homogeneously into the Al matrix, see Figure 6b, where the formation of intermetallic phases occurred. The reaction between Al and Co resulted in an intermetallic phase seam around the pure particles, see Figure 6c, for Ni, and two phase seams appeared, see Figure 6d. Compared with Co and Ni, Fe has a stronger tendency to form an intermetallic phase with Al because the whole particle is changed, see Figure 6e,f. Ni and Co develop the same phase seams for 10 mass-% and 30 mass-%, while Fe develops different phases. For the characterisation of the respective intermetallic phases, an EDX mapping analysis with a Helios Nanolab 600 was carried out to analyse the distribution of the elements in the Al and particle transition area. The investigations were conducted under a high vacuum, and an accelerating voltage of 15.0 kV and a beam current of 1.4 nA were used. A working distance of 5.1 mm was selected for Al with Co particles, 4.7 mm for Fe, and 6.0 mm for Ni. The findings for the Co particle, for example, are shown in Figure 7. As a result of the measured components, an intermetallic phase with the composition Al\({}_{3}\)Co\({}_{2}\) was formed around the pure Co particle. Ni forms Al\({}_{3}\)Ni on the outside and Al\({}_{3}\)Ni\({}_{2}\) on the inside around the pure Ni particle. The 10 mass-% Fe led to the formation of Al\({}_{13}\)Fe\({}_{4}\) phases. Further investigations are currently being conducted for the phase determination of the 30 mass-%, but the microstructural images in Figure 6f indicate that a different phase was formed.
# Systematic Mapping Study on Remote Sensing in Agriculture
## 2 Research Methodology
### Definition of the Search Strategy  
After analysing different bibliographic databases, the search was done in Scopus ([[https://www.scopus.com/](https://www.scopus.com/)]([https://www.scopus.com/](https://www.scopus.com/))). This database indexes an important number of journals and conferences with a certain level of rigor [86], many of them coinciding with those of the other databases. The search was done in December 2019.  
Another key factor in the bibliographic search is the definition of the search string used in the database. Scopus allows to define a complex search string with Boolean operators and wildcards. This string takes a form similar to a sentence with subject-adjective-verb-complement, where all the main possibilities are considered for each component. Thus, it was formulated as follows.  
_TITLE_ ( (_sensing OR sensor\({}^{\star}\) OR imaging OR imagery OR image\({}^{\star}\)_) _AND_ (_remote OR satellite\({}^{\star}\) OR SAR_ **OR**_UAV_**OR**_airborne_**OR**_hyperspectral_**OR**_thermal_**OR**_infrared_**OR**_\"hyperspectral\"_)_**AND**_(detect\({}^{\star}\) OR management OR monitor\({}^{\star}\) OR estimat\({}^{\star}\) OR classification OR recognition OR diagnosis OR identify\({}^{\star}\)) _AND_ (_agricultur\({}^{\star}\) OR plant OR crop\({}^{\star}\) OR cultivar\({}^{\star}\) OR plague OR canopy OR leaves OR infestation_)_ ).  
Observe that this string is applied on the title of the paper rather than the abstract or the content, as this is more specific and produces less false-positives. The combination of the four groups of words with an _AND_ requires that at least one word of each group appears in the title. The first group corresponds to the _subject_, including terms related to the scope of images and capture devices: sensing, sensor, imaging, imagery, and image. The second group is the _adjective_, and it is used to refine the previous set introducing the property of being remote. It contains the words remote, satellite, SAR, UAV, airborne, hyperspectral, thermal, infrared, and hyperspectral. Although the last four terms do not necessarily involve \"remote\", these types of spectral information are more common in remote sensing applications. The third group is the _verb_, so the terms correspond to the actions being performed with the images. These terms are the main tasks of RSA applications: detection, management, monitoring, estimation, classification, recognition, diagnosis, and identification. Finally, the fourth group is the _complement_, which indicates some property of the task. This allows to remove research works in remote sensing that are not related to agriculture. The terms in this group are agriculture, plant, crop, cultivar, plague, canopy, leaves, and infestation. The final search string was refined in a trial-and-error process, observing that the papers found are in the area of RSA, and no relevant papers are lost. For example, the terms \"plague\" and \"infestation\" were included after observing that some papers did not include other terms in the complement.
# Assessing Cyber Challenges of Maritime Navigation
###### Abstract  
This paper provides a close investigation into the landscape of both cyber threats and actual incidents in the maritime sector, identifying the cyber trends and challenges as they relate to safe navigation and marine shipping. As an important subset of cyber threats that impact many maritime systems, the vulnerabilities of satellite navigation systems, in particular the Global Positioning System (GPS), receive special attention. For this article, a systematic literature review was conducted, complemented by the research and analysis of a specific spoofing event. Analyzing available resources, we might summarize that a shift in mind-set is essential to direct more attention and resources toward cybersecurity as well as the necessity for manufacturers to improve the cybersecurity of their products, as shipping systems currently remain vulnerable to cybercriminals. There is a need for multiple positioning, navigation, and timing (PNT) systems onboard maritime vessels to complement GPS-only navigation. The use of multiple satellite navigation constellations, public as well as private, in combination with the terrestrial components of an enhanced LOng-RAnge Navigation (eLoran) system and ports' laser-based aid system for berthing and docking should provide the shipping industry with the direly needed increased protection from cyber-attackers for the foreseeable future.  
m aritime cyber; cybersecurity; the safety of navigation; shipboard systems; GPS jamming and spoofing +
Footnote †: journal: Marine Science and Engineering  
_Article_