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26 pages, 15828 KiB  
Article
Optimization of Offshore Saline Aquifer CO2 Storage in Smeaheia Using Surrogate Reservoir Models
by Behzad Amiri, Ashkan Jahanbani Ghahfarokhi, Vera Rocca and Cuthbert Shang Wui Ng
Algorithms 2024, 17(10), 452; https://doi.org/10.3390/a17100452 - 11 Oct 2024
Cited by 1 | Viewed by 1339
Abstract
Machine learning-based Surrogate Reservoir Models (SRMs) can replace/augment multi-physics numerical simulations by replicating the reservoir simulation results with reduced computational effort while maintaining accuracy compared with numerical simulations. This research will demonstrate SRMs’ potential in long-term simulations and optimization of geological carbon storage [...] Read more.
Machine learning-based Surrogate Reservoir Models (SRMs) can replace/augment multi-physics numerical simulations by replicating the reservoir simulation results with reduced computational effort while maintaining accuracy compared with numerical simulations. This research will demonstrate SRMs’ potential in long-term simulations and optimization of geological carbon storage in a real-world geological setting and address challenges in big data curation and model training. The present study focuses on CO2 storage in the Smeaheia saline aquifer. Two SRMs were created using Deep Neural Networks (DNNs) to predict CO2 saturation and pressure over all grid blocks for 50 years. 18 million samples and 31 features, including reservoir static and dynamic properties, build the input data. Models comprise 3–5 hidden layers with 128–512 units apiece. SRMs showed a runtime improvement of 300 times and an accuracy of 99% compared to the 3D numerical simulator. The genetic algorithm was then employed to determine the optimal rate and duration of CO2 injection, which maximizes the volume of injected CO2 while ensuring storage operations’ safety through constraints. The optimization continued for the reproduction of 100 generations, each containing 100 individuals, without any hyperparameter tuning. Finally, the optimization results confirm the significant potential of Smeaheia for storing 170 Mt CO2. Full article
(This article belongs to the Special Issue Nature-Inspired Algorithms in Machine Learning (2nd Edition))
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<p>ANN forward propagation algorithm for computing the next layer units from input data.</p>
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<p>Common activation functions and their derivatives, from left: ReLU, hyperbolic tangent, and sigmoid.</p>
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<p>The workflow implemented in this study.</p>
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<p>Smeaheia’s prospects location with respect to GN 101 survey [<a href="#B49-algorithms-17-00452" class="html-bibr">49</a>,<a href="#B64-algorithms-17-00452" class="html-bibr">64</a>].</p>
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<p>Gas saturation distribution in year 2300, after 25 years CO<sub>2</sub> injection with the rate of 5.872 × 10<sup>6</sup> sm<sup>3</sup>/day since 2022.</p>
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<p>Storage structure, consisting of top and bottom surfaces, and faults.</p>
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<p>Well location sensitivity analysis in zones Alpha, Beta, and Gamma.</p>
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<p>Saturation distribution in 2072. 35-year CO<sub>2</sub> injection in newly designed injection well Alpha.</p>
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<p>Proxy modeling workflow.</p>
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<p>Bottom hole pressure of numerical simulation cases used for SRM training.</p>
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<p>Pressure and CO<sub>2</sub> saturation distribution and error maps after 50 years injection with the rate of 1.79881 × 10<sup>6</sup> Sm<sup>3</sup>/day, 1st layer.</p>
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<p>Pressure and CO<sub>2</sub> saturation distribution and error maps after 50 years injection with the rate of 1.79881 × 10<sup>6</sup> Sm<sup>3</sup>/day, 1st layer.</p>
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<p>Pressure and CO<sub>2</sub> saturation distribution and error maps after 25 years injection with the rate of 7.61035 × 10<sup>6</sup> Sm<sup>3</sup>/day, 70th layer.</p>
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<p>Pressure and CO<sub>2</sub> saturation distribution and error maps after 25 years injection with the rate of 7.61035 × 10<sup>6</sup> Sm<sup>3</sup>/day, 70th layer.</p>
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<p>Pressure and CO<sub>2</sub> saturation distribution and error maps after 50 years injection with the rate of 3.45925 × 10<sup>6</sup> Sm<sup>3</sup>/day, 1st layer.</p>
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<p>CO<sub>2</sub> Saturation distribution in 2100, 28 years after stopping CO<sub>2</sub> injection at rate of 4.683495 × 10<sup>6</sup> Sm<sup>3</sup>/day for 50 years.</p>
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<p>Pressure and CO<sub>2</sub> saturation distribution and error maps after 50 years injection with the rate of 4.683495 × 10<sup>6</sup> Sm<sup>3</sup>/day (optimum case), 1st layer.</p>
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<p>Pressure and CO<sub>2</sub> saturation distribution and error maps after 50 years injection with the rate of 4.683495 × 10<sup>6</sup> Sm<sup>3</sup>/day (optimum case), 1st layer.</p>
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28 pages, 4809 KiB  
Article
Insurance Analytics with Clustering Techniques
by Charlotte Jamotton, Donatien Hainaut and Thomas Hames
Risks 2024, 12(9), 141; https://doi.org/10.3390/risks12090141 - 5 Sep 2024
Viewed by 1159
Abstract
The K-means algorithm and its variants are well-known clustering techniques. In actuarial applications, these partitioning methods can identify clusters of policies with similar attributes. The resulting partitions provide an actuarial framework for creating maps of dominant risks and unsupervised pricing grids. This research [...] Read more.
The K-means algorithm and its variants are well-known clustering techniques. In actuarial applications, these partitioning methods can identify clusters of policies with similar attributes. The resulting partitions provide an actuarial framework for creating maps of dominant risks and unsupervised pricing grids. This research article aims to adapt well-established clustering methods to complex insurance datasets containing both categorical and numerical variables. To achieve this, we propose a novel approach based on Burt distance. We begin by reviewing the K-means algorithm to establish the foundation for our Burt distance-based framework. Next, we extend the scope of application of the mini-batch and fuzzy K-means variants to heterogeneous insurance data. Additionally, we adapt spectral clustering, a technique based on graph theory that accommodates non-convex cluster shapes. To mitigate the computational complexity associated with spectral clustering’s O(n3) runtime, we introduce a data reduction method for large-scale datasets using our Burt distance-based approach. Full article
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<p>Illustration of two policies in Burt space with three modalities.</p>
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<p>Illustration of the partitioning of the numeric data into 10 clusters with the K-means algorithm (using Euclidean distance).</p>
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<p>Illustration of the partitioning of the discretized numeric data (projected in Burt space) into 10 clusters with the Burt distance-based K-means algorithm.</p>
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<p>Clustering results obtained with the Burt distance-based K-means algorithm on a simulated dataset.</p>
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<p>Burt distance-based K-means metrics. (<b>Left</b>) plot: evolution of the total intra-class inertia. (<b>Right</b>) plot: evolution of the deviance.</p>
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<p>Partition quality (in solid lines, measured by the average deviance over 10 random seeds) and running time (dotted lines) with respect to the number of clusters.</p>
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<p>Illustration of the partition of non-convex data with the K-means and spectral clustering algorithms. Each cluster is identified by a color (black or green). The centroids are represented with a diamond shape.</p>
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<p>Vertices, edges, and weights of a graph.</p>
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<p>Ring representation of a period with <span class="html-italic">N</span> steps.</p>
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<p>Graph with <span class="html-italic">K</span> sub-graphs.</p>
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<p>Two weakly connected sub-graphs.</p>
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<p>(<b>Left</b>) Partition of a non-convex dataset with spectral clustering. (<b>Right</b>) Pairs of eigenvectors’ coordinates <math display="inline"><semantics> <msub> <mfenced separators="" open="(" close=")"> <msub> <mi>U</mi> <mrow> <mi>i</mi> <mo>,</mo> <mn>1</mn> </mrow> </msub> <mo>,</mo> <msub> <mi>U</mi> <mrow> <mi>i</mi> <mo>,</mo> <mn>2</mn> </mrow> </msub> </mfenced> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> <mo>,</mo> <mo>…</mo> <mo>,</mo> <mi>n</mi> </mrow> </msub> </semantics></math>.</p>
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<p>(<b>Left</b>) Spectral clustering partitioning of a non-convex dataset that has been preliminarily reduced with the K-means algorithm. (<b>Right</b>) Pairs of eigenvectors’ coordinates <math display="inline"><semantics> <msub> <mfenced separators="" open="(" close=")"> <msub> <mi>U</mi> <mrow> <mi>i</mi> <mo>,</mo> <mn>1</mn> </mrow> </msub> <mo>,</mo> <msub> <mi>U</mi> <mrow> <mi>i</mi> <mo>,</mo> <mn>2</mn> </mrow> </msub> </mfenced> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> <mo>,</mo> <mo>…</mo> <mo>,</mo> <mi>n</mi> </mrow> </msub> </semantics></math>.</p>
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16 pages, 888 KiB  
Article
Analyzing Docker Vulnerabilities through Static and Dynamic Methods and Enhancing IoT Security with AWS IoT Core, CloudWatch, and GuardDuty
by Vishnu Ajith, Tom Cyriac, Chetan Chavda, Anum Tanveer Kiyani, Vijay Chennareddy and Kamran Ali
IoT 2024, 5(3), 592-607; https://doi.org/10.3390/iot5030026 - 4 Sep 2024
Viewed by 1750
Abstract
In the age of fast digital transformation, Docker containers have become one of the central technologies for flexible and scalable application deployment. However, this has opened a new dimension of challenges in security, which are skyrocketing with increased technology adoption. This paper discerns [...] Read more.
In the age of fast digital transformation, Docker containers have become one of the central technologies for flexible and scalable application deployment. However, this has opened a new dimension of challenges in security, which are skyrocketing with increased technology adoption. This paper discerns these challenges through a manifold approach: first, comprehensive static analysis by Trivy, and second, real-time dynamic analysis by Falco in order to uncover vulnerabilities in Docker environments pre-deployment and during runtime. One can also find similar challenges in security within the Internet of Things (IoT) sector, due to the huge number of devices connected to WiFi networks, from simple data breaches such as brute force attacks and unauthorized access to large-scale cyber attacks against critical infrastructure, which represent only a portion of the problems. In connection with this, this paper is calling for the execution of robust AWS cloud security solutions: IoT Core, CloudWatch, and GuardDuty. IoT Core provides a secure channel of communication for IoT devices, and CloudWatch offers detailed monitoring and logging. Additional security is provided by GuardDuty’s automatized threat detection system, which continuously seeks out potential threats across network traffic. Armed with these technologies, we try to build a more resilient and privacy-oriented IoT while ensuring the security of our digital existence. The result is, therefore, an all-inclusive work on security in both Docker and IoT domains, which might be considered one of the most important efforts so far to strengthen the digital infrastructure against fast-evolving cyber threats, combining state-of-the-art methods of static and dynamic analyses for Docker security with advanced, cloud-based protection for IoT devices. Full article
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<p>Process flow—Trivy.</p>
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<p>The graphical representation of vulnerabilities detected in the Docker container image.</p>
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<p>Trivy scan command-line output showing detailed vulnerability information.</p>
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<p>Process flow—Falco.</p>
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<p>Terminal output showcasing anomalies detected in real time by Falco.</p>
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<p>Metrics loaded by Falco to Prometheus.</p>
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<p>Process flow—IoT brute force attack simulation.</p>
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<p>Error count and success rate with respect to the login attempts triggered by the brute force attack.</p>
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<p>Alarm generated indicating the failed login attempt.</p>
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<p>Email notification.</p>
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<p>Execution result.</p>
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20 pages, 3209 KiB  
Article
IPLog: An Efficient Log Parsing Method Based on Few-Shot Learning
by Shuxian Liu, Libo Yun, Shuaiqi Nie, Guiheng Zhang and Wei Li
Electronics 2024, 13(16), 3324; https://doi.org/10.3390/electronics13163324 - 21 Aug 2024
Viewed by 889
Abstract
Log messages from enterprise-level software systems contain crucial runtime details. Engineers can convert log messages into structured data through log parsing, laying the foundation for downstream tasks such as log anomaly detection. Existing log parsing schemes usually underperform in production environments for several [...] Read more.
Log messages from enterprise-level software systems contain crucial runtime details. Engineers can convert log messages into structured data through log parsing, laying the foundation for downstream tasks such as log anomaly detection. Existing log parsing schemes usually underperform in production environments for several reasons: first, they often ignore the semantics of log messages; second, they are often not adapted to different systems, and their performance varies greatly; and finally, they are difficult to adapt to the complexity and variety of log formats in the real environment. In response to the limitations of current approaches, we introduce IPLog (Intelligent Parse Log), a parsing method designed to address these issues. IPLog samples a limited set of log samples based on the distribution of templates in the system’s historical logs, and allows the model to make full use of the small number of log samples to recognize common patterns of keywords and parameters through few-shot learning, and thus can be easily adapted to different systems. In addition, IPLog can further improve the grouping accuracy of log templates through a novel manual feedback merge query strategy based on the longest common prefix, thus enhancing the model’s adaptability to handle complex log formats in production environments. We conducted experiments on four newly released public log datasets, and the experimental results show that IPLog can achieve an average grouping accuracy (GA) of 0.987 and parsing accuracy (PA) of 0.914 on the four public datasets, which are the best among the mainstream parsing schemes. These results demonstrate that IPLog is effective for log parsing tasks. Full article
(This article belongs to the Section Computer Science & Engineering)
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<p>Example of log parsing.</p>
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<p>Overview of IPLog (where the top gray box represents the steps in the offline training phase of IPLog, the blue box is the process of prompt tuning, the yellow box represents the steps of online parsing, and the bottom green box is the postprocessing process).</p>
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<p>Offline training phase (<b>left</b>) and online parsing phase (<b>right</b>) of IPLog, where the offline-trained model can be directly used for online parsing.</p>
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<p>Manual feedback merge query.</p>
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<p>Comparison of parsing results of different parsing methods for ten randomly selected log messages in HDFS (green log templates represent correct parsing).</p>
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<p>Comparison of parsing results of different parsing methods for ten randomly selected log messages in HDFS (green log templates represent correct parsing).</p>
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<p>Comparison of different sampling algorithms.</p>
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16 pages, 1123 KiB  
Article
Docker Performance Evaluation across Operating Systems
by Maciej Sobieraj and Daniel Kotyński
Appl. Sci. 2024, 14(15), 6672; https://doi.org/10.3390/app14156672 - 31 Jul 2024
Cited by 1 | Viewed by 1600
Abstract
Docker has gained significant popularity in recent years. With the introduction of Docker Desktop for Windows and macOS, there is a need to determine the impact of the operating system on the performance of the Docker platform. This paper aims to investigate the [...] Read more.
Docker has gained significant popularity in recent years. With the introduction of Docker Desktop for Windows and macOS, there is a need to determine the impact of the operating system on the performance of the Docker platform. This paper aims to investigate the performance of Docker containers based on the operating system. One of the fundamental goals of this study is to conduct a comprehensive analysis of the Docker architecture. This technology utilizes Linux kernel virtualization mechanisms such as namespaces and cgroups. Upon analyzing the distribution of Docker Desktop for Windows and Docker Desktop for macOS, it was discovered that running the Docker environment on these requires a lightweight virtual machine that emulates the Linux system. This information suggests that the additional virtualization layer may hinder the performance of non-Linux operating systems hosting Docker containers. The paper presents a performance test of the Docker runtime on Linux, Microsoft Windows, and macOS. The test evaluated specific aspects of operating system performance on a MacBook computer with an ×86/64 processor architecture. The experiment carried out examined the performance in terms of CPU speed, I/O speed, and network throughput. This test measured the efficiency of software that utilizes various system resources. Full article
(This article belongs to the Section Electrical, Electronics and Communications Engineering)
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<p>Linux PID namespace visualization.</p>
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<p>Leibnitz method <math display="inline"><semantics> <mi>π</mi> </semantics></math> calculation in C.</p>
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<p>Sysbench CPU test.</p>
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<p>Sysbench I/O test of sequential/random read.</p>
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<p>Sysbench I/O test of sequential/random write.</p>
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<p>Sysbench I/O test of combined random write/read.</p>
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<p>Throughput test between two containers using TCP protocol.</p>
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<p>Throughput test between two containers using UDP protocol.</p>
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<p>Packet loss test between two containers using UDP protocol.</p>
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<p>Throughput test between host system and container using TCP protocol.</p>
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<p>7zip built-in benchmark score—using 1/4/8 hardware threads.</p>
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<p>pgbench score for a database with the scale factor of 5.</p>
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<p>Response time of Apache server before and during a Slowlorris attack.</p>
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20 pages, 2100 KiB  
Article
Parallel Algorithm on Multicore Processor and Graphics Processing Unit for the Optimization of Electric Vehicle Recharge Scheduling
by Vincent Roberge, Katerina Brooks and Mohammed Tarbouchi
Electronics 2024, 13(9), 1783; https://doi.org/10.3390/electronics13091783 - 5 May 2024
Viewed by 1761
Abstract
Electric vehicles (EVs) are becoming more and more popular as they provide significant environmental benefits compared to fossil-fuel vehicles. However, they represent substantial loads on the power grid, and the scheduling of EV charging can be a challenge, especially in large parking lots. [...] Read more.
Electric vehicles (EVs) are becoming more and more popular as they provide significant environmental benefits compared to fossil-fuel vehicles. However, they represent substantial loads on the power grid, and the scheduling of EV charging can be a challenge, especially in large parking lots. This paper presents a metaheuristic-based approach parallelized on multicore processors (CPU) and graphics processing units (GPU) to optimize the scheduling of EV charging in a single smart parking lot. The proposed method uses a particle swarm optimization algorithm that takes as input the arrival time, the departure time, and the power demand of the vehicles and produces an optimized charging schedule for all vehicles in the parking lot, which minimizes the overall charging cost while respecting the chargers’ capacity and the parking lot feeder capacity. The algorithm exploits task-level parallelism for the multicore CPU implementation and data-level parallelism for the GPU implementation. The proposed algorithm is tested in simulation on parking lots containing 20 to 500 EVs. The parallel implementation on CPUs provides a speedup of 7.1x, while the implementation on a GPU provides a speedup of up to 247.6x. The parallel implementation on a GPU is able to optimize the charging schedule for a 20-EV parking lot in 0.87 s and a 500-EV lot in just under 30 s. These runtimes allow for real-time computation when a vehicle arrives at the parking lot or when the electricity cost profile changes. Full article
(This article belongs to the Special Issue Vehicle Technologies for Sustainable Smart Cities and Societies)
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<p>Generic architecture of an NVIDIA GPU.</p>
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<p>Execution model of the GPU.</p>
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<p>Flowchart of the multi-run PSO.</p>
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<p>Flowchart of the parallel multi-run PSO using OpenMP.</p>
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<p>Parallel map primitive squaring each value of the input vector.</p>
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<p>Parallel reduction primitive to find the maximum value.</p>
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<p>Flowchart of the parallel multi-run PSO on GPU using CUDA.</p>
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<p>Runtime and speedup of the parallel implementation on multicore CPU using OpenMP.</p>
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<p>Runtime and speedup of the parallel implementation on GPU.</p>
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22 pages, 1237 KiB  
Article
On the Search for Potentially Anomalous Traces of Cosmic Ray Particles in Images Acquired by Cmos Detectors for a Continuous Stream of Emerging Observational Data
by Marcin Piekarczyk and Tomasz Hachaj
Sensors 2024, 24(6), 1835; https://doi.org/10.3390/s24061835 - 13 Mar 2024
Cited by 1 | Viewed by 1110
Abstract
In this paper we propose the method for detecting potential anomalous cosmic ray particle tracks in big data image dataset acquired by Complementary Metal-Oxide-Semiconductors (CMOS). Those sensors are part of scientific infrastructure of Cosmic Ray Extremely Distributed Observatory (CREDO). The use of Incremental [...] Read more.
In this paper we propose the method for detecting potential anomalous cosmic ray particle tracks in big data image dataset acquired by Complementary Metal-Oxide-Semiconductors (CMOS). Those sensors are part of scientific infrastructure of Cosmic Ray Extremely Distributed Observatory (CREDO). The use of Incremental PCA (Principal Components Analysis) allowed approximation of loadings which might be updated at runtime. Incremental PCA with Sequential Karhunen-Loeve Transform results with almost identical embedding as basic PCA. Depending on image preprocessing method the weighted distance between coordinate frame and its approximation was at the level from 0.01 to 0.02 radian for batches with size of 10,000 images. This significantly reduces the necessary calculations in terms of memory complexity so that our method can be used for big data. The use of intuitive parameters of the potential anomalies detection algorithm based on object density in embedding space makes our method intuitive to use. The sets of anomalies returned by our proposed algorithm do not contain any typical morphologies of particle tracks shapes. Thus, one can conclude that our proposed method effectively filter-off typical (in terms of analysis of variance) shapes of particle tracks by searching for those that can be treated as significantly different from the others in the dataset. We also proposed method that can be used to find similar objects, which gives it the potential, for example, to be used in minimal distance-based classification and CREDO image database querying. The proposed algorithm was tested on more than half a million (570,000+) images that contains various morphologies of cosmic particle tracks. To our knowledge, this is the first study of this kind based on data collected using a distributed network of CMOS sensors embedded in the cell phones of participants collaborating within the citizen science paradigm. Full article
(This article belongs to the Special Issue Multi-Sensor Systems for Object Tracking—2nd Edition)
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<p>Comparison of results of potential anomalies detection with (<a href="#FD4-sensors-24-01835" class="html-disp-formula">4</a>) evaluated with Jaccard index (<a href="#FD8-sensors-24-01835" class="html-disp-formula">8</a>). Types of preprocessing and values of <math display="inline"><semantics> <mi>ϵ</mi> </semantics></math> are in <a href="#sensors-24-01835-t003" class="html-table">Table 3</a>. The <span class="html-italic">k</span> parameter in (<a href="#FD4-sensors-24-01835" class="html-disp-formula">4</a>) was arbitrarily set to 3.</p>
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<p>Comparison of results of potential anomalies detection with (<a href="#FD4-sensors-24-01835" class="html-disp-formula">4</a>) evaluated with Overlap coefficient (<a href="#FD9-sensors-24-01835" class="html-disp-formula">9</a>). Types of preprocessing and values of <math display="inline"><semantics> <mi>ϵ</mi> </semantics></math> are in <a href="#sensors-24-01835-t003" class="html-table">Table 3</a>. The <span class="html-italic">k</span> parameter in (<a href="#FD4-sensors-24-01835" class="html-disp-formula">4</a>) was arbitrarily set to 3.</p>
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<p>The first sixteen potential anomalies for each of the four preprocessing methods calculated for basic PCA with <math display="inline"><semantics> <mrow> <mo>(</mo> <mi>α</mi> <mo>=</mo> <mn>2.4</mn> <mo>,</mo> <mi>k</mi> <mo>=</mo> <mn>3</mn> <mo>)</mo> </mrow> </semantics></math> in (<a href="#FD4-sensors-24-01835" class="html-disp-formula">4</a>).</p>
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<p>Comparison of coordinate frames obtained with basic PCA to coordinate frames obtained with Incremental PCA for a different number of data used when approximating PCA with Algorithm 2. Each point on the plot shows the cfd value (<a href="#FD7-sensors-24-01835" class="html-disp-formula">7</a>) for the PCA coordinate axes calculated on the whole data and the coordinate axes calculated by Incremental PCA on a certain percentage of the whole data, that is, for example, the PCA axes calculated on the whole set with B. Replicate preprocessing and the axes calculated with Incremental PCA with B. Replicate preprocessing calculated on 10%, 20%, 30% of the data etc.</p>
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<p>A comparison of Jaccard Index and Overlap Coefficient for the method of finding potential anomalies (<a href="#FD4-sensors-24-01835" class="html-disp-formula">4</a>) with the parameters <math display="inline"><semantics> <mrow> <mo>(</mo> <mi>α</mi> <mo>=</mo> <mn>2.4</mn> <mo>,</mo> <mspace width="0.166667em"/> <mi>k</mi> <mo>=</mo> <mn>3</mn> <mo>)</mo> </mrow> </semantics></math> for PCA and Incremental PCA counted on increasing numbers of data. We performed embedding and potential anomalies detection on the entire dataset.</p>
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<p>Test of the effectiveness of the method that detects similar objects according to Equation (<a href="#FD6-sensors-24-01835" class="html-disp-formula">6</a>). For this purpose, we used the preprocessing algorithm B. Reflect and we generated features using basic PCA. The first column contains image <math display="inline"><semantics> <msub> <mi>I</mi> <mi>j</mi> </msub> </semantics></math> (see Equation (<a href="#FD6-sensors-24-01835" class="html-disp-formula">6</a>)). Each subsequent column contain the most similar images, the further to the left the Euclidean distance between embedding <math display="inline"><semantics> <msub> <mi>E</mi> <mi>i</mi> </msub> </semantics></math> and <math display="inline"><semantics> <msub> <mi>E</mi> <mi>j</mi> </msub> </semantics></math> is higher (second from left is most similar to first, first from right is the least similar from all seven).</p>
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<p>Examples of anomalies detected by the proposed method with parameters <math display="inline"><semantics> <mrow> <mo>(</mo> <mi>α</mi> <mo>=</mo> <mn>2.3</mn> <mo>,</mo> <mspace width="0.166667em"/> <mi>k</mi> <mo>=</mo> <mn>5</mn> <mo>)</mo> </mrow> </semantics></math>, B. Replicate preprocessing, basic PCA. We chose them because they represent a variety of deviations from the typical shapes of expected most typical trajectories: (<b>a</b>) two separated signals, (<b>b</b>) energy deposit wit colored halo effect, (<b>c</b>) worm-like signal with unexpected right angle, (<b>d</b>) untypical closed loop trajectory, (<b>e</b>) wide band with low energy deposit, (<b>f</b>) probably corrupted image file, (<b>g</b>) colored energy deposit with tail, (<b>h</b>) dot-like signal with too large energy deposit.</p>
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27 pages, 1086 KiB  
Article
Implementing Internet of Things Service Platforms with Network Function Virtualization Serverless Technologies
by Mauro Femminella and Gianluca Reali
Future Internet 2024, 16(3), 91; https://doi.org/10.3390/fi16030091 - 8 Mar 2024
Cited by 1 | Viewed by 2102
Abstract
The need for adaptivity and scalability in telecommunication systems has led to the introduction of a software-based approach to networking, in which network functions are virtualized and implemented in software modules, based on network function virtualization (NFV) technologies. The growing demand for low [...] Read more.
The need for adaptivity and scalability in telecommunication systems has led to the introduction of a software-based approach to networking, in which network functions are virtualized and implemented in software modules, based on network function virtualization (NFV) technologies. The growing demand for low latency, efficiency, flexibility and security has placed some limitations on the adoption of these technologies, due to some problems of traditional virtualization solutions. However, the introduction of lightweight virtualization approaches is paving the way for new and better infrastructures for implementing network functions. This article discusses these new virtualization solutions and shows a proposal, based on serverless computing, that uses them to implement container-based virtualized network functions for the delivery of advanced Internet of Things (IoT) services. It includes open source software components to implement both the virtualization layer, implemented through Firecracker, and the runtime environment, based on Kata containers. A set of experiments shows that the proposed approach is fast, in order to boost new network functions, and more efficient than some baseline solutions, with minimal resource footprint. Therefore, it is an excellent candidate to implement NFV functions in the edge deployment of serverless services for the IoT. Full article
(This article belongs to the Special Issue Applications of Wireless Sensor Networks and Internet of Things)
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<p>General scheme for serverless computing.</p>
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<p>IoT mMTC services belonging to different scenarios can be deployed in a flexible and dynamic way by leveraging NFV features. The proposed lightweight architecture is shown as the NFV infrastructure block, compliant with the ETSI NFV standard.</p>
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<p>New entities in NFV control plane (CISM, CCM, CIR) introduced to manage CIS cluster in NFVI as envisioned in Ref. [<a href="#B30-futureinternet-16-00091" class="html-bibr">30</a>]. Solid lines indicate NFV interfaces, dashed lines indicate other additional interfaces. Reference points names are omitted to improve readability.</p>
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<p>NFV infrastructure as envisioned in Ref. [<a href="#B35-futureinternet-16-00091" class="html-bibr">35</a>], providing containers on bare metal (right side of NFVI) and VMs (left side of NFVI).</p>
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<p>NetBricks defines an NF connecting blocks from five different programming abstraction.</p>
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<p>Kata container nests a pod, encapsulating containers’ processes and namespaces, in a microVM for enhanced isolation.</p>
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<p>Firecracker enables the deployment of lightweight microVMs through a minimal virtual machine monitor.</p>
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<p>RAM usage and boot time during NetBricks Kata container deployment using QEMU and Firecracker hypervisors. Red lines refer to Firecracker RAM usage, and blue lines refer to QEMU RAM usage. Dotted lines indicate memory consumption for simple container deployment, whereas continuous lines represent RAM usage overhead required by container deployment followed by a VNF call. The two dash–dotted vertical lines show the average container boot time for Firecracker (red) and QEMU (blue).</p>
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<p>Message delivery ratio of a Kafka broker VNF running in a Kata container on a (blue) QEMU hypervisor, and a (red) Firecracker hypervisor.</p>
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<p>Percentage CPU consumption of a Kafka broker VNF running in a Kata container on a (blue) QEMU hypervisor, and a (red) Firecracker hypervisor.</p>
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<p>Batch write latency (in ms) for a Kafka broker VNF running in a Kata container on (blue) a QEMU hypervisor, and (red) a Firecracker hypervisor.</p>
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26 pages, 2375 KiB  
Article
Dynamic Knowledge Management in an Agent-Based Extended Green Cloud Simulator
by Zofia Wrona, Maria Ganzha, Marcin Paprzycki and Stanisław Krzyżanowski
Energies 2024, 17(4), 780; https://doi.org/10.3390/en17040780 - 6 Feb 2024
Cited by 1 | Viewed by 1157
Abstract
Cloud infrastructures operate in highly dynamic environments, and today, energy-focused optimization become crucial. Moreover, the concept of extended cloud infrastructure, which, among others, uses green energy, started to gain traction. This introduces a new level of dynamicity to the ecosystem, as “processing components” [...] Read more.
Cloud infrastructures operate in highly dynamic environments, and today, energy-focused optimization become crucial. Moreover, the concept of extended cloud infrastructure, which, among others, uses green energy, started to gain traction. This introduces a new level of dynamicity to the ecosystem, as “processing components” may “disappear” and “come back”, specifically in scenarios where the lack/return of green energy leads to shutting down/booting back servers at a given location. Considered use cases may involve introducing new types of resources (e.g., adding containers with server racks with “next-generation processors”). All such situations require the dynamic adaptation of “system knowledge”, i.e., runtime system adaptation. In this context, an agent-based digital twin of the extended green cloud infrastructure is proposed. Here, knowledge management is facilitated with an explainable Rule-Based Expert System, combined with Expression Languages. The tests were run using Extended Green Cloud Simulator, which allows the modelling of cloud infrastructures powered (partially) by renewable energy sources. Specifically, the work describes scenarios in which: (1) a new hardware resource is introduced in the system; (2) the system component changes its resource; and (3) system user changes energy-related preferences. The case study demonstrates how rules can facilitate control of energy efficiency with an example of an adaptable compromise between pricing and energy consumption. Full article
(This article belongs to the Special Issue Smart Energy Systems: Learning Methods for Control and Optimization)
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<p>Architecture of the agent system in EGCS.</p>
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<p>Process of allocating the resource for the job execution.</p>
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<p>Model of resource and resource characteristic representation.</p>
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<p>Alternation of Cloud Network Agent knowledge base in response to adding new Server Agent in a given region.</p>
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<p>Process of the adaptation of rule set in the agent knowledge map.</p>
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<p>Architecture of EGCS agents.</p>
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<p>Topology of the system used in Scenario 1.</p>
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<p>System logs presenting the recognition of Server 4 in CNA 2.</p>
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<p>Before and after of the CNA 2 knowledge adaptation.</p>
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<p>Allocation of Server 4 for the execution of GPU-Client job.</p>
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<p>Topology of the system used in Scenario 2.</p>
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<p>Runtime modification of <span class="html-italic">Server2</span> processor.</p>
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<p>EL handlers specified for managing new Server 2 knowledge.</p>
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<p>Results of modification of <span class="html-italic">Server2</span> resources.</p>
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<p>Results of the adaptation of <span class="html-italic">CNA</span> knowledge.</p>
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<p>Button allowing to generate weather deterioration event.</p>
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<p>System logs reflecting the successful exchange of Server 1 and Server 2 behaviors.</p>
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<p>System logs reflecting that CNA 1 rejects the jobs for which execution is too long.</p>
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<p>Adaptation of the system illustrated on the cloud infrastructure graph.</p>
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<p>System logs indicating successful adaptation of pricing criteria for Server 1 and Server 2.</p>
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<p>Specification of individual client pricing preference.</p>
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<p>System logs presenting application of custom offer comparator for GreenClient.</p>
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<p>Information about GreenClient job being assigned for execution using Server 3.</p>
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21 pages, 7974 KiB  
Article
ProvGRP: A Context-Aware Provenance Graph Reduction and Partition Approach for Facilitating Attack Investigation
by Jiawei Li, Ru Zhang and Jianyi Liu
Electronics 2024, 13(1), 100; https://doi.org/10.3390/electronics13010100 - 25 Dec 2023
Viewed by 1481
Abstract
Attack investigation is a crucial technique in proactively defending against sophisticated attacks. Its purpose is to identify attack entry points and previously unknown attack traces through comprehensive analysis of audit data. However, a major challenge arises from the vast and redundant nature of [...] Read more.
Attack investigation is a crucial technique in proactively defending against sophisticated attacks. Its purpose is to identify attack entry points and previously unknown attack traces through comprehensive analysis of audit data. However, a major challenge arises from the vast and redundant nature of audit logs, making attack investigation difficult and prohibitively expensive. To address this challenge, various technologies have been proposed to reduce audit data, facilitating efficient analysis. However, most of these techniques rely on defined templates without considering the rich context information of events. Moreover, these methods fail to remove false dependencies caused by the coarse-grained nature of logs. To address these limitations, this paper proposes a context-aware provenance graph reduction and partition approach for facilitating attack investigation named ProvGRP. Specifically, three features are proposed to determine whether system events are the same behavior from multiple dimensions. Based on the insight that information paths belonging to the same high-level behavior share similar information flow patterns, ProvGRP generates information paths containing context, and identifies and merges paths that share similar flow patterns. Experimental results show that ProvGRP can efficiently reduce provenance graphs with minimal loss of crucial information, thereby facilitating attack investigation in terms of runtime and results. Full article
(This article belongs to the Special Issue Data Security and Privacy: Challenges and Techniques)
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<p>Cases are used to compare and illustrate our approach ProvGRP and existing reduction techniques. The gray nodes and edges in Case 1 represent events that are actually unrelated to the black nodes. CPR/PCAR [<a href="#B13-electronics-13-00100" class="html-bibr">13</a>], NodeMerge [<a href="#B12-electronics-13-00100" class="html-bibr">12</a>], and LogApprox [<a href="#B15-electronics-13-00100" class="html-bibr">15</a>] fail to reduce Case 2 effectively.</p>
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<p>The provenance graph of the Kimsuky attack scenario. The gray boxes and directed edges represent attack events. The simplified provenance graph describes several behaviors, which are associated together by long-running process chrome.exe. <b>Limitation.</b> The complete provenance graph depicted in <a href="#electronics-13-00100-f002" class="html-fig">Figure 2</a> is huge and complex, and contains 19,306 nodes and 116,732 edges. It is difficult and time-consuming to conduct attack investigation in this graph. Moreover, the above graph is only constructed from audit logs collected on a single host within 12 h. We combine the above attack scenario to provide a more intuitive analysis of the two main limitations of existing reduction techniques.</p>
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<p>The black box indicates the overall workflow of ProvGRP. ProvGRP’s input is audit logs collected from different operating systems (left of the black box). ProvGRP outputs reduced provenance graphs for facilitating attack investigation.</p>
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<p>Different behaviors are divided into different subgraphs by partitioning long-running processes into execution partitions.</p>
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<p>The process of merging paths based on similarity. Nodes and edges in the dotted box represent the merged path. (<b>A</b>) represents the segmented subgraph, (<b>B</b>) represents the intermediate result in the iteration, and (<b>C</b>) represents the final result of the provenance subgraph.</p>
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<p>Statistical analysis results of Time Density of two publicly available datasets (<b>A</b>) ATLAS and (<b>B</b>) DAPRA CADETS. The blue line indicates the analysis result of all events, and the dotted green line indicates the statistics result of attack events.</p>
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<p>Statistical analysis results of Similarity Value of two publicly available datasets (<b>A</b>) ATLAS and (<b>B</b>) DAPRA CADETS.</p>
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<p>Statistical analysis results of operation distribution of two publicly available datasets (<b>A</b>) ATLAS and (<b>B</b>) DAPRA CADETS. The base 10 logarithm is performed on the number of events.</p>
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<p>The three metrics value for ProvGRP in different attack scenarios.</p>
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<p>Comparison of reduction performance of different reduction methods on the two datasets CADETS (<b>A</b>) and ATLAS (<b>B</b>).</p>
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<p>Comparison of metrics of different methods.</p>
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11 pages, 979 KiB  
Proceeding Paper
Container Security in Cloud Environments: A Comprehensive Analysis and Future Directions for DevSecOps
by Santosh Ugale and Amol Potgantwar
Eng. Proc. 2023, 59(1), 57; https://doi.org/10.3390/engproc2023059057 - 18 Dec 2023
Cited by 2 | Viewed by 2337
Abstract
In recent years, the security of containers has become a crucial aspect of modern software applications’ security and integrity. Containers are extensively used due to their lightweight and portable nature, allowing swift and agile deployment across different environments. However, the increasing popularity of [...] Read more.
In recent years, the security of containers has become a crucial aspect of modern software applications’ security and integrity. Containers are extensively used due to their lightweight and portable nature, allowing swift and agile deployment across different environments. However, the increasing popularity of containers has led to unique security risks, including vulnerabilities in container images, misconfigured containers, and insecure runtime environments. Containers are often built using public repository images and base image vulnerability is inherited by containers. Container images may contain outdated components or services, including system libraries and dependencies and known vulnerabilities from these components can be exploited. Images downloaded from untrusted sources may include malicious code that compromises other containers running in the same network or the host system. Base images may include unnecessary software or services that increase the attack surface and potential vulnerabilities. Several security measures have been implemented to address these risks, such as container image scanning, container orchestration security, and runtime security monitoring. Implementing a solid security policy and updating containers with the latest patches can significantly improve container security. Given the increasing adoption of containers, organizations must prioritize container security to protect their applications and data. This work presents automated, robust security techniques for continuous integration and continuous development pipelines, and the added overhead is empirically analyzed. Then, we nail down specific research and technological problems the DevSecOps community encounters and appropriate initial fixes. Our results will make it possible to make judgments that are enforced when using DevSecOps techniques in enterprise security and cloud-native applications. Full article
(This article belongs to the Proceedings of Eng. Proc., 2023, RAiSE-2023)
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<p>Container deployment architecture.</p>
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<p>Proposed container security framework flowchart.</p>
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<p>Proposed container security framework.</p>
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<p>Test result graph using GRYPE.</p>
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<p>Test result graph using Trivy.</p>
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16 pages, 768 KiB  
Article
Impact of Secure Container Runtimes on File I/O Performance in Edge Computing
by Kyungwoon Lee, Jeongsu Kim, Ik-Hyeon Kwon, Hyunchan Park and Cheol-Ho Hong
Appl. Sci. 2023, 13(24), 13329; https://doi.org/10.3390/app132413329 - 18 Dec 2023
Cited by 1 | Viewed by 1677
Abstract
Containers enable high performance and easy deployment due to their lightweight architecture, thus facilitating resource utilization in edge computing nodes. Secure container runtimes have attracted significant attention because of the necessity for overcoming the security vulnerabilities of containers. As the runtimes adopt an [...] Read more.
Containers enable high performance and easy deployment due to their lightweight architecture, thus facilitating resource utilization in edge computing nodes. Secure container runtimes have attracted significant attention because of the necessity for overcoming the security vulnerabilities of containers. As the runtimes adopt an additional layer such as virtual machines and user-space kernels to enforce isolation, the container performance can be degraded. Even though previous studies presented experimental results on performance evaluations of secure container runtimes, they lack a detailed analysis of the root causes that affect the performance of the runtimes. This paper explores the architecture of three secure container runtimes in detail: Kata containers, gVisor, and Firecracker. We focus on file I/O, which is one of the key aspects of container performance. In addition, we present the results of the user- and kernel-level profiling and reveal the major factors that impact the file I/O performance of the runtimes. As a result, we observe three key findings: (1) Firecracker shows the highest file I/O performance as it allows for utilizing the page cache inside VMs, and (2) Kata containers offer the lowest file I/O performance by consuming the largest amount of CPU resources. Also, we observe that gVisor scales well as the block size increases because the file I/O requests are mainly handled by the host OS similar to native applications. Full article
(This article belongs to the Special Issue Advances in Edge Computing for Internet of Things)
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<p>Different architectures of representative secure container runtimes: Kata containers, gVisor, and Firecracker. (<b>a</b>) Kata containers, (<b>b</b>) gVisor, and (<b>c</b>) Firecracker.</p>
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<p>File operations of Kata containers. (<b>a</b>) Overview, and (<b>b</b>) symbol-level analysis of the file I/O stack.</p>
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<p>File operations of gVisor. (<b>a</b>) Overview, and (<b>b</b>) symbol-level analysis of the file I/O stack.</p>
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<p>File operations of Firecracker. (<b>a</b>) Overview, and (<b>b</b>) symbol-level analysis of the file I/O stack.</p>
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<p>Sequential file I/O performance of runc, Kata containers (Kata), gVisor, and Firecracker (FC) with different block sizes. (<b>a</b>) Sequential read, and (<b>b</b>) sequential write.</p>
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<p>CPU usage in processing sequential file I/O operations under runc (R), Kata containers (K), gVisor (G), and Firecracker (F). (<b>a</b>) Sequential read, and (<b>b</b>) sequential write.</p>
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<p>Random file I/O performance of runc, Kata containers (Kata), gVisor, and Firecracker (FC) with different block sizes. (<b>a</b>) Random read, and (<b>b</b>) random write.</p>
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<p>CPU usage in processing random file I/O operations under runc (R), Kata containers (K), gVisor (G), and Firecracker (F). (<b>a</b>) Random read, and (<b>b</b>) random write.</p>
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<p>Symbol-level profiling of I/O processing in Kata containers.</p>
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<p>Symbol-level profiling of I/O processing in gVisor.</p>
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<p>Symbol-level profiling of I/O processing in Firecracker.</p>
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20 pages, 1475 KiB  
Article
CanaryExp: A Canary-Sensitive Automatic Exploitability Evaluation Solution for Vulnerabilities in Binary Programs
by Hui Huang, Yuliang Lu, Kailong Zhu and Jun Zhao
Appl. Sci. 2023, 13(23), 12556; https://doi.org/10.3390/app132312556 - 21 Nov 2023
Cited by 1 | Viewed by 1474
Abstract
We propose CanaryExp, an exploitability evaluation solution for vulnerabilities among binary programs protected by StackGuard. CanaryExp devises three novel techniques, namely canary leakage proof of concept generation, canary leaking analysis time exploitation, and dynamic canary-relocation-based exploitability evaluation. The canary leakage proof of concept [...] Read more.
We propose CanaryExp, an exploitability evaluation solution for vulnerabilities among binary programs protected by StackGuard. CanaryExp devises three novel techniques, namely canary leakage proof of concept generation, canary leaking analysis time exploitation, and dynamic canary-relocation-based exploitability evaluation. The canary leakage proof of concept input generation mechanism first traces the target program’s execution, transforming the execution state into some canary leaking state, from which some canary leaking input is derived. This input can be deemed as proof that some vulnerability that can lead to canary leakage exists. The canary leaking analysis time exploit generation then performs incremental analysis based on the canary leaking input, crafting analysis time exploit that can complete vulnerability exploitation in the analysis time environment. Based on the analysis time exploit, the dynamic canary-relocation-based exploitability evaluation component collects the necessary metadata, on which an exploitation session is automatically constructed that can not only leak the runtime canary and relocate it in the input stream but also evaluate the exploitability of the desired vulnerability. Using a benchmark containing six test programs, eight challenges from some network challenging events and four real-world applications, we demonstrate that CanaryExp can generate canary leaking samples more effectively than existing test case generation methods and automatically evaluate the exploitability for vulnerabilities among programs where the StackGuard protection mechanism is deployed. Full article
(This article belongs to the Special Issue Cyber Security Systems: Emerging Technologies for a Secure Future)
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<p>An example of exploitation of vulnerability in a StackGuard-protected program. (<b>a</b>) Source code of the example. (<b>b</b>) Disassembly view of function <span class="html-italic">func</span> in this example. This view is generated by the well-known interactive disassembler IDA Pro. (<b>c</b>) Stack frame of <span class="html-italic">func</span>. (<b>d</b>) Steps we believe AEG systems should take to handle this case.</p>
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<p>Overview of CanaryExp.</p>
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<p>Patched function snippet. The red frame demonstrates the patched part.</p>
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<p>Canary-leakage-sensitive fuzzing.</p>
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40 pages, 8198 KiB  
Article
The Semantic Adjacency Criterion in Time Intervals Mining
by Alexander Shknevsky, Yuval Shahar and Robert Moskovitch
Big Data Cogn. Comput. 2023, 7(4), 173; https://doi.org/10.3390/bdcc7040173 - 9 Nov 2023
Viewed by 1904
Abstract
We propose a new pruning constraint when mining frequent temporal patterns to be used as classification and prediction features, the Semantic Adjacency Criterion [SAC], which filters out temporal patterns that contain potentially semantically contradictory components, exploiting each medical domain’s knowledge. We have [...] Read more.
We propose a new pruning constraint when mining frequent temporal patterns to be used as classification and prediction features, the Semantic Adjacency Criterion [SAC], which filters out temporal patterns that contain potentially semantically contradictory components, exploiting each medical domain’s knowledge. We have defined three SAC versions and tested them within three medical domains (oncology, hepatitis, diabetes) and a frequent-temporal-pattern discovery framework. Previously, we had shown that using SAC enhances the repeatability of discovering the same temporal patterns in similar proportions in different patient groups within the same clinical domain. Here, we focused on SAC’s computational implications for pattern discovery, and for classification and prediction, using the discovered patterns as features, by four different machine-learning methods: Random Forests, Naïve Bayes, SVM, and Logistic Regression. Using SAC resulted in a significant reduction, across all medical domains and classification methods, of up to 97% in the number of discovered temporal patterns, and in the runtime of the discovery process, of up to 98%. Nevertheless, the highly reduced set of only semantically transparent patterns, when used as features, resulted in classification and prediction models whose performance was at least as good as the models resulting from using the complete temporal-pattern set. Full article
(This article belongs to the Special Issue Data Science in Health Care)
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<p>An example of our new Semantic Adjacent Constraint. Three syntactically equal instances of the same interval-based temporal pattern, which includes the symbolic intervals, “&lt;Medication-dose-level = High&gt; Before &lt;Hemoglobin [HGB]-level = Low&gt;” are shown. Instance No. 1 describes a situation in which the two intervals are adjacent, and no contradicting value exists between them, and thus preserves semantic transparency. Instance No. 2a describes a situation in which the two intervals are <span class="html-italic">not</span> semantically adjacent, since there is an unexpected (from the point of view of the domain expert) High hemoglobin-level value between them that contradicts the pattern’s expected semantics. Instance No. 2b, similarly, contains an unexpected medication-dose level (Low) between the two symbolic intervals. Both of the instances of the non-SAC obeying patterns will be pruned out.</p>
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<p>An example of a TIRP representation, containing five instances of symbolic time intervals of three types, A, B, and C, and all of their pair-wise temporal relations.</p>
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<p>Example of possible contradicting instances within a two-sized TIRP, when considering additional symbolic intervals that might exist in the same database, and the full range of temporal relations possible between two intervals. Cases 1, 2, 3, 6, 8, and 10 contradict the semantics of the TIRP defined above. Cases 4, 5, 7, and 9 appear outside the temporal relation gap within the TIRP and do not contradict it according to our current SAC definition.</p>
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<p>An example of the difference between the sequential version of SAC and other possible versions that do not consider only successive symbolic time intervals.</p>
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<p>A possible TIRP that might be discovered by using the SSAC; the first three symbols represent a “Symbolic Gradient” temporal pattern of decreasing values of the Hemoglobin State abstractions, while the last two symbols present a “Counting” temporal pattern of two successive low hemoglobin tests.</p>
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<p>The runtime of the KarmaLego algorithm for different minimal vertical support [MVS] thresholds on data mined using seven temporal relations in the oncology data set. Each graph represents one temporal abstraction method and displays all of the SAC versions (if any) used (the legend appears on the <b>upper right</b>).</p>
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<p>The runtime of the KarmaLego algorithm for different minimal vertical support [MVS] thresholds on data mined using three temporal relations in the oncology data set. Each graph represents one temporal abstraction method and displays all of the SAC versions (if any) used (the legend appears on the <b>upper right</b>).</p>
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<p>The number of discovered TIRPs using seven temporal relations in the oncology data set for different minimal vertical support [MVS] thresholds. Each graph represents one temporal abstraction method and displays all of the SAC versions (if any) used (the legend appears on the <b>upper right</b>).</p>
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<p>The number of discovered TIRPs for different minimal vertical support [MVS] thresholds using three temporal relations in the oncology data set. Each graph represents one temporal abstraction method and displays all of the SAC versions (if any) used (the legend appears on the <b>upper right</b>).</p>
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<p>The runtime of the KarmaLego algorithm for different minimal vertical support [MVS] thresholds on data mined using seven temporal relations in the hepatitis data set. Each graph represents one temporal abstraction method and displays all of the SAC versions (if any) used (the legend appears on the <b>upper right</b>).</p>
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<p>The runtime of the KarmaLego algorithm for different minimal vertical support [MVS] thresholds on data mined using three temporal relations in the hepatitis data set. Each graph represents one temporal abstraction method and displays all of the SAC versions (if any) used (the legend appears on the <b>upper right</b>).</p>
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<p>The number of discovered TIRPs for different minimal vertical support [MVS] thresholds using seven temporal relations in the hepatitis data set. Each graph represents one temporal abstraction method and displays for each method all of the SAC versions (if any) used (the legend appears on the <b>upper right</b>).</p>
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<p>The number of discovered TIRPs for different minimal vertical support [MVS] thresholds using three temporal relations in the hepatitis data set. Each graph represents one temporal abstraction method and displays all of the SAC versions (if any) used (the legend appears on the <b>upper right</b>).</p>
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<p>The runtime of the KarmaLego algorithm for different minimal vertical support [MVS] thresholds on data mined using seven temporal relations in the diabetes data set. Each graph represents one temporal abstraction method and displays all of the SAC versions (if any) used (the legend appears on the <b>upper right</b>).</p>
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<p>The runtime of the KarmaLego algorithm for different minimal vertical support [MVS] thresholds on data mined using three temporal relations in the diabetes data set. Each graph represents one temporal abstraction method and displays all of the SAC versions (if any) used (the legend appears on the <b>upper right</b>).</p>
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<p>The number of discovered TIRPs for different minimal vertical support [MVS] thresholds using seven temporal relations in the diabetes data set. Each graph represents one temporal abstraction method and displays all of the SAC versions (if any) used (the legend appears on the <b>upper right</b>).</p>
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<p>The number of discovered TIRPs for different minimal vertical support [MVS] thresholds using three temporal relations in the diabetes data set. Each graph represents one temporal abstraction method and displays all of the SAC versions (if any) used (the legend appears on the <b>upper right</b>).</p>
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<p>The mean AUC of using the four classifier-induction methods in all three domains when using any of the three SAC versions during the TIRP discovery process compared to not using any SAC version during that process. RF = Random Forest; NB = Naïve Bayes; SMO = Support Vector Machine; LR = Logistic Regression.</p>
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<p>The classification performance results when using the different SAC versions in the oncology data set partitioned by TIRP representation methods.</p>
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<p>The classification performance results when using the different SAC versions in the oncology data set partitioned by the temporal abstraction methods.</p>
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<p>The classification performance results when using the different SAC versions in the hepatitis data set partitioned by TIRP representation methods.</p>
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<p>The classification performance results when using the different SAC versions in the hepatitis data set partitioned by the temporal abstraction methods.</p>
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<p>The prediction performance results when using the different SAC versions in the diabetes data set partitioned by TIRP representation methods.</p>
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<p>The prediction performance results when using the different SAC versions in the diabetes data set partitioned by the temporal abstraction methods.</p>
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27 pages, 7589 KiB  
Article
Ship Target Detection Method in Synthetic Aperture Radar Images Based on Block Thumbnail Particle Swarm Optimization Clustering
by Shiqi Huang, Ouya Zhang and Qilong Chen
Remote Sens. 2023, 15(20), 4972; https://doi.org/10.3390/rs15204972 - 15 Oct 2023
Viewed by 1489
Abstract
Ship target detection is an important application of synthetic aperture radar (SAR) imaging remote sensing in ocean monitoring and management. However, SAR imaging is a form of coherence imaging, meaning that there is a large amount of speckle noise in each SAR image. [...] Read more.
Ship target detection is an important application of synthetic aperture radar (SAR) imaging remote sensing in ocean monitoring and management. However, SAR imaging is a form of coherence imaging, meaning that there is a large amount of speckle noise in each SAR image. This seriously affects the detection of an SAR image ship target when the fuzzy C-means (FCM) clustering method is used, resulting in numerous errors and incomplete detection. It is also associated with a slow detection speed, which easily falls into the local minima. To overcome these issues, a new method based on block thumbnail particle swarm optimization clustering (BTPSOC) was proposed for SAR image ship target detection. The BTPSOC algorithm uses block thumbnails to segment the main pixels, which improves the resistance to noise interference and segmentation accuracy, enhances the ability to process different types of SAR images, and reduces the runtime. When particle swarm optimization (PSO) technology is used to optimize the FCM clustering center, global optimization is achieved, the clustering performance is improved, the risk of falling into the local minima is overcome, and the stability is improved. The SAR images from two datasets containing ship targets were used in verification experiments. The experimental results show that the BTPSOC algorithm can effectively detect the ship target in SAR images and that it maintains good integrity with regard to the detailed information from the target region. At the same time, experiments comparing the deep convolution neural network (CNN) and constant false alarm rate (CFAR) were conducted. Full article
(This article belongs to the Special Issue Microwave Remote Sensing for Object Detection)
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Graphical abstract

Graphical abstract
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<p>Block diagram of the BTPSOC algorithm.</p>
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<p>Generation process of feature-similar pixel groups (Different colors represent different pixels or groups of pixels).</p>
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<p>Original SAR image and its thumbnail.</p>
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<p>Representation of particles and clustering centers (* is the position of a particle).</p>
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<p>Original SAR ship images used for the experiments ((<b>a1</b>–<b>a5</b>) and (<b>b1</b>–<b>b5</b>) represent SAR images of different scenes, respectively).</p>
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<p>Influence curve of different pixel block sizes <math display="inline"><semantics> <mi>L</mi> </semantics></math> on the BTPSOC algorithm ((<b>a</b>) is the segmentation accuracy, (<b>b</b>) is the running time).</p>
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<p>The effect of different histogram groups <math display="inline"><semantics> <mi>G</mi> </semantics></math> on the performance of the BTPSOC algorithm ((<b>a</b>) is the segmentation accuracy, (<b>b</b>) is the running time, (<b>c</b>) is the percentage of remaining pixels (PRP)).</p>
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<p>Segmentation results of the SAR ship images in the SSDD dataset obtained using different algorithms. ((<b>A</b>–<b>E</b>) is original SAR images, (<b>b1</b>–<b>b5</b>) is ground truth of (<b>a</b>), (<b>c1</b>–<b>c5</b>) is the results of FCM algorithm, (<b>d1</b>–<b>d5</b>) is the results of PSO algorithm, (<b>e1</b>–<b>e5</b>) is the results of FKPFCM algorithm, (<b>f1</b>–<b>f5</b>) is the results of BTPSOC algorithm).</p>
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<p>Comparison of the <span class="html-italic">REC</span> values of different methods. (c1–c5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(c1–c5), d1–d5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(d1–d5), e1–e5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(e1–e5), f1–f5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(f1–f5)).</p>
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<p>Comparison of the <span class="html-italic">PRE</span> values of different methods. (c1–c5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(c1–c5), d1–d5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(d1–d5), e1–e5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(e1–e5), f1–f5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(f1–f5)).</p>
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<p>Comparison of the <span class="html-italic">FM</span> values of different methods. (c1–c5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(c1–c5), d1–d5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(d1–d5), e1–e5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(e1–e5), f1–f5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(f1–f5)).</p>
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<p>Comparison of the <span class="html-italic">ACC</span> values of different methods. (c1–c5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(c1–c5), d1–d5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(d1–d5), e1–e5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(e1–e5), f1–f5 is <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>(f1–f5)).</p>
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<p>Comparison of the <span class="html-italic">ROC</span> curves obtained using different algorithms. ((<b>a</b>) is results of <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>A, (<b>b</b>) is results of <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>B, (<b>c</b>) is results of <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>C, (<b>d</b>) is results of <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>D, (<b>e</b>) is results of <a href="#remotesensing-15-04972-f008" class="html-fig">Figure 8</a>E).</p>
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<p>Comparison of the average runtime of different algorithms.</p>
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<p>Experiment result comparison of the FCN, U-Net, and BTPSOC algorithms.</p>
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<p>Experiment result comparison of the CA-CFAR and BTPSOC algorithms.</p>
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<p>Experiment results of the SAR images in the SSSD dataset obtained using different algorithms. ((<b>A</b>–<b>E</b>) is original SAR images, (<b>b1</b>–<b>b5</b>) is ground truth of (<b>a</b>), (<b>c1</b>–<b>c5</b>) is the results of PSO algorithm, (<b>d1</b>–<b>d5</b>) is the results of FCM algorithm, (<b>e1</b>–<b>e5</b>) is the results of FKPFCM algorithm, (<b>f1</b>–<b>f5</b>) is the results of BTPSOC algorithm).</p>
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