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Keywords = in-memory processing framework

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23 pages, 360 KB  
Article
In-Memory Shellcode Runner Detection in Internet of Things (IoT) Networks: A Lightweight Behavioral and Semantic Analysis Framework
by Jean Rosemond Dora, Ladislav Hluchý and Michal Staňo
Sensors 2025, 25(17), 5425; https://doi.org/10.3390/s25175425 - 2 Sep 2025
Cited by 1 | Viewed by 1211
Abstract
The widespread expansion of Internet of Things devices has ushered in an era of unprecedented connectivity. However, it has simultaneously exposed these resource-constrained systems to novel and advanced cyber threats. Among the most impressive and complex attacks are those leveraging in-memory shellcode runners [...] Read more.
The widespread expansion of Internet of Things devices has ushered in an era of unprecedented connectivity. However, it has simultaneously exposed these resource-constrained systems to novel and advanced cyber threats. Among the most impressive and complex attacks are those leveraging in-memory shellcode runners (malware), which perform malicious payloads directly in memory, circumventing conventional disk-based detection security mechanisms. This paper presents a comprehensive framework, both academic and technical, for detecting in-memory shellcode runners, particularly tailored to the unique characteristics of these networks. We analyze and review the limitations of existing security parameters in this area, highlight the different challenges posed by those constraints, and propose a multi-layered approach that combines entropy-based anomaly scoring, lightweight behavioral monitoring, and novel Graph Neural Network methods for System Call Semantic Graph Analysis. Our proposal focuses on runtime analysis of process memory, system call patterns (e.g., Syscall ID, Process ID, Hooking, Win32 application programming interface), and network behavior to identify the subtle indicators of compromise that portray in-memory attacks, even in the absence of conventional file-system artifacts. Through meticulous empirical evaluation against simulated and real-world Internet of Things attacks (red team engagements, penetration testing), we demonstrate the efficiency and a few challenges of our approach, providing a crucial step towards enhancing the security posture of these critical environments. Full article
(This article belongs to the Special Issue Internet of Things Cybersecurity)
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25 pages, 1615 KB  
Article
Efficient Parallel Processing of Big Data on Supercomputers for Industrial IoT Environments
by Isam Mashhour Al Jawarneh, Lorenzo Rosa, Riccardo Venanzi, Luca Foschini and Paolo Bellavista
Electronics 2025, 14(13), 2626; https://doi.org/10.3390/electronics14132626 - 29 Jun 2025
Cited by 3 | Viewed by 1584
Abstract
The integration of distributed big data analytics into modern industrial environments has become increasingly critical, particularly with the rise of data-intensive applications and the need for real-time processing at the edge. While High-Performance Computing (HPC) systems offer robust petabyte-scale capabilities for efficient big [...] Read more.
The integration of distributed big data analytics into modern industrial environments has become increasingly critical, particularly with the rise of data-intensive applications and the need for real-time processing at the edge. While High-Performance Computing (HPC) systems offer robust petabyte-scale capabilities for efficient big data analytics, the performance of big data frameworks, especially on ARM-based HPC systems, remains underexplored. This paper presents an extensive experimental study on deploying Apache Spark 3.0.2, the de facto standard in-memory processing system, on an ARM-based HPC system. This study conducts a comprehensive performance evaluation of Apache Spark through representative big data workloads, including K-means clustering, to assess the effects of latency variations, such as those induced by network delays, memory bottlenecks, or computational overheads, on application performance in industrial IoT and edge computing environments. Our findings contribute to an understanding of how big data frameworks like Apache Spark can be effectively deployed and optimized on ARM-based HPC systems, particularly when leveraging vectorized instruction sets such as SVE, contributing to the broader goal of enhancing the integration of cloud–edge computing paradigms in modern industrial environments. We also discuss potential improvements and strategies for leveraging ARM-based architectures to support scalable, efficient, and real-time data processing in Industry 4.0 and beyond. Full article
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43 pages, 2159 KB  
Systematic Review
A Systematic Review and Classification of HPC-Related Emerging Computing Technologies
by Ehsan Arianyan, Niloofar Gholipour, Davood Maleki, Neda Ghorbani, Abdolah Sepahvand and Pejman Goudarzi
Electronics 2025, 14(12), 2476; https://doi.org/10.3390/electronics14122476 - 18 Jun 2025
Viewed by 2440
Abstract
In recent decades, access to powerful computational resources has brought about a major transformation in science, with supercomputers drawing significant attention from academia, industry, and governments. Among these resources, high-performance computing (HPC) has emerged as one of the most critical processing infrastructures, providing [...] Read more.
In recent decades, access to powerful computational resources has brought about a major transformation in science, with supercomputers drawing significant attention from academia, industry, and governments. Among these resources, high-performance computing (HPC) has emerged as one of the most critical processing infrastructures, providing a suitable platform for evaluating and implementing novel technologies. In this context, the development of emerging computing technologies has opened up new horizons in information processing and the delivery of computing services. In this regard, this paper systematically reviews and classifies emerging HPC-related computing technologies, including quantum computing, nanocomputing, in-memory architectures, neuromorphic systems, serverless paradigms, adiabatic technology, and biological solutions. Within the scope of this research, 142 studies which were mostly published between 2018 and 2025 are analyzed, and relevant hardware solutions, domain-specific programming languages, frameworks, development tools, and simulation platforms are examined. The primary objective of this study is to identify the software and hardware dimensions of these technologies and analyze their roles in improving the performance, scalability, and efficiency of HPC systems. To this end, in addition to a literature review, statistical analysis methods are employed to assess the practical applicability and impact of these technologies across various domains, including scientific simulation, artificial intelligence, big data analytics, and cloud computing. The findings of this study indicate that emerging HPC-related computing technologies can serve as complements or alternatives to classical computing architectures, driving substantial transformations in the design, implementation, and operation of high-performance computing infrastructures. This article concludes by identifying existing challenges and future research directions in this rapidly evolving field. Full article
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24 pages, 2877 KB  
Article
Memory-Efficient Batching for Time Series Transformer Training: A Systematic Evaluation
by Phanwadee Sinthong, Nam Nguyen, Vijay Ekambaram, Arindam Jati, Jayant Kalagnanam and Peeravit Koad
Algorithms 2025, 18(6), 350; https://doi.org/10.3390/a18060350 - 5 Jun 2025
Viewed by 3081
Abstract
Transformer-based time series models are being increasingly employed for time series data analysis. However, their training remains memory intensive, especially with high-dimensional data and extended look-back windows, while model-level memory optimizations are well studied, the batch formation process remains an underexplored factor to [...] Read more.
Transformer-based time series models are being increasingly employed for time series data analysis. However, their training remains memory intensive, especially with high-dimensional data and extended look-back windows, while model-level memory optimizations are well studied, the batch formation process remains an underexplored factor to performance inefficiency. This paper introduces a memory-efficient batching framework based on view-based sliding windows operating directly on GPU-resident tensors. This approach eliminates redundant data materialization caused by tensor stacking and reduces data transfer volumes without modifying model architectures. We present two variants of our solution: (1) per-batch optimization for datasets exceeding GPU memory, and (2) dataset-wise optimization for in-memory workloads. We evaluate our proposed batching framework systematically using peak GPU memory consumption and epoch runtime as efficiency metrics across varying batch sizes, sequence lengths, feature dimensions, and model architectures. Results show consistent memory savings, averaging 90% and runtime improvements of up to 33% across multiple transformer-based models (Informer, Autoformer, Transformer, and PatchTST) and a linear baseline (DLinear) without compromising model accuracy. We extensively validate our method using synthetic and standard real-world benchmarks, demonstrating accuracy preservation and practical scalability in distributed GPU environments. The proposed method highlights batch formation process as a critical component for improving training efficiency. Full article
(This article belongs to the Section Parallel and Distributed Algorithms)
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22 pages, 3570 KB  
Article
High-Performance Computing and Parallel Algorithms for Urban Water Demand Forecasting
by Georgios Myllis, Alkiviadis Tsimpiris, Stamatios Aggelopoulos and Vasiliki G. Vrana
Algorithms 2025, 18(4), 182; https://doi.org/10.3390/a18040182 - 22 Mar 2025
Cited by 4 | Viewed by 1991
Abstract
This paper explores the application of parallel algorithms and high-performance computing (HPC) in the processing and forecasting of large-scale water demand data. Building upon prior work, which identified the need for more robust and scalable forecasting models, this study integrates parallel computing frameworks [...] Read more.
This paper explores the application of parallel algorithms and high-performance computing (HPC) in the processing and forecasting of large-scale water demand data. Building upon prior work, which identified the need for more robust and scalable forecasting models, this study integrates parallel computing frameworks such as Apache Spark for distributed data processing, Message Passing Interface (MPI) for fine-grained parallel execution, and CUDA-enabled GPUs for deep learning acceleration. These advancements significantly improve model training and deployment speed, enabling near-real-time data processing. Apache Spark’s in-memory computing and distributed data handling optimize data preprocessing and model execution, while MPI provides enhanced control over custom parallel algorithms, ensuring high performance in complex simulations. By leveraging these techniques, urban water utilities can implement scalable, efficient, and reliable forecasting solutions critical for sustainable water resource management in increasingly complex environments. Additionally, expanding these models to larger datasets and diverse regional contexts will be essential for validating their robustness and applicability in different urban settings. Addressing these challenges will help bridge the gap between theoretical advancements and practical implementation, ensuring that HPC-driven forecasting models provide actionable insights for real-world water management decision-making. Full article
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25 pages, 1936 KB  
Article
A Scalable Framework for Sensor Data Ingestion and Real-Time Processing in Cloud Manufacturing
by Massimo Pacella, Antonio Papa, Gabriele Papadia and Emiliano Fedeli
Algorithms 2025, 18(1), 22; https://doi.org/10.3390/a18010022 - 4 Jan 2025
Cited by 13 | Viewed by 4252
Abstract
Cloud Manufacturing enables the integration of geographically distributed manufacturing resources through advanced Cloud Computing and IoT technologies. This paradigm promotes the development of scalable and adaptable production systems. However, existing frameworks face challenges related to scalability, resource orchestration, and data security, particularly in [...] Read more.
Cloud Manufacturing enables the integration of geographically distributed manufacturing resources through advanced Cloud Computing and IoT technologies. This paradigm promotes the development of scalable and adaptable production systems. However, existing frameworks face challenges related to scalability, resource orchestration, and data security, particularly in rapidly evolving decentralized manufacturing settings. This study presents a novel nine-layer architecture designed specifically to address these issues. Central to this framework is the use of Apache Kafka for robust, high-throughput data ingestion, and Apache Spark Streaming to enhance real-time data processing. This framework is underpinned by a microservice-based architecture that ensures a high scalability and reduced latency. Experimental validation using sensor data from the UCI Machine Learning Repository demonstrated substantial improvements in processing efficiency and throughput compared with conventional frameworks. Key components, such as RabbitMQ, contribute to low-latency performance, whereas Kafka ensures data durability and supports real-time application. Additionally, the in-memory data processing of Spark Streaming enables rapid and dynamic data analysis, yielding actionable insights. The experimental results highlight the potential of the framework to enhance operational efficiency, resource utilization, and data security, offering a resilient solution suited to the demands of modern industrial applications. This study underscores the contribution of the framework to advancing Cloud Manufacturing by providing detailed insights into its performance, scalability, and applicability to contemporary manufacturing ecosystems. Full article
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20 pages, 740 KB  
Article
A Variation-Aware Binary Neural Network Framework for Process Resilient In-Memory Computations
by Minh-Son Le, Thi-Nhan Pham, Thanh-Dat Nguyen and Ik-Joon Chang
Electronics 2024, 13(19), 3847; https://doi.org/10.3390/electronics13193847 - 28 Sep 2024
Cited by 1 | Viewed by 2057
Abstract
Binary neural networks (BNNs) that use 1-bit weights and activations have garnered interest as extreme quantization provides low power dissipation. By implementing BNNs as computation-in-memory (CIM), which computes multiplication and accumulations on memory arrays in an analog fashion, namely, analog CIM, we can [...] Read more.
Binary neural networks (BNNs) that use 1-bit weights and activations have garnered interest as extreme quantization provides low power dissipation. By implementing BNNs as computation-in-memory (CIM), which computes multiplication and accumulations on memory arrays in an analog fashion, namely, analog CIM, we can further improve the energy efficiency to process neural networks. However, analog CIMs are susceptible to process variation, which refers to the variability in manufacturing that causes fluctuations in the electrical properties of transistors, resulting in significant degradation in BNN accuracy. Our Monte Carlo simulations demonstrate that in an SRAM-based analog CIM implementing the VGG-9 BNN model, the classification accuracy on the CIFAR-10 image dataset is degraded to below 50% under process variations in a 28 nm FD-SOI technology. To overcome this problem, we present a variation-aware BNN framework. The proposed framework is developed for SRAM-based BNN CIMs since SRAM is most widely used as on-chip memory; however, it is easily extensible to BNN CIMs based on other memories. Our extensive experimental results demonstrate that under process variation of 28 nm FD-SOI, with an SRAM array size of 128×128, our framework significantly enhances classification accuracies on both the MNIST hand-written digit dataset and the CIFAR-10 image dataset. Specifically, for the CONVNET BNN model on MNIST, accuracy improves from 60.24% to 92.33%, while for the VGG-9 BNN model on CIFAR-10, accuracy increases from 45.23% to 78.22%. Full article
(This article belongs to the Special Issue Research on Key Technologies for Hardware Acceleration)
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44 pages, 8494 KB  
Review
Survey of Deep Learning Accelerators for Edge and Emerging Computing
by Shahanur Alam, Chris Yakopcic, Qing Wu, Mark Barnell, Simon Khan and Tarek M. Taha
Electronics 2024, 13(15), 2988; https://doi.org/10.3390/electronics13152988 - 29 Jul 2024
Cited by 14 | Viewed by 19706
Abstract
The unprecedented progress in artificial intelligence (AI), particularly in deep learning algorithms with ubiquitous internet connected smart devices, has created a high demand for AI computing on the edge devices. This review studied commercially available edge processors, and the processors that are still [...] Read more.
The unprecedented progress in artificial intelligence (AI), particularly in deep learning algorithms with ubiquitous internet connected smart devices, has created a high demand for AI computing on the edge devices. This review studied commercially available edge processors, and the processors that are still in industrial research stages. We categorized state-of-the-art edge processors based on the underlying architecture, such as dataflow, neuromorphic, and processing in-memory (PIM) architecture. The processors are analyzed based on their performance, chip area, energy efficiency, and application domains. The supported programming frameworks, model compression, data precision, and the CMOS fabrication process technology are discussed. Currently, most commercial edge processors utilize dataflow architectures. However, emerging non-von Neumann computing architectures have attracted the attention of the industry in recent years. Neuromorphic processors are highly efficient for performing computation with fewer synaptic operations, and several neuromorphic processors offer online training for secured and personalized AI applications. This review found that the PIM processors show significant energy efficiency and consume less power compared to dataflow and neuromorphic processors. A future direction of the industry could be to implement state-of-the-art deep learning algorithms in emerging non-von Neumann computing paradigms for low-power computing on edge devices. Full article
(This article belongs to the Special Issue AI for Edge Computing)
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20 pages, 1280 KB  
Article
A Novel Algorithm for Multi-Criteria Ontology Merging through Iterative Update of RDF Graph
by Mohammed Suleiman Mohammed Rudwan and Jean Vincent Fonou-Dombeu
Big Data Cogn. Comput. 2024, 8(3), 19; https://doi.org/10.3390/bdcc8030019 - 21 Feb 2024
Cited by 1 | Viewed by 2913
Abstract
Ontology merging is an important task in ontology engineering to date. However, despite the efforts devoted to ontology merging, the incorporation of relevant features of ontologies such as axioms, individuals and annotations in the output ontologies remains challenging. Consequently, existing ontology-merging solutions produce [...] Read more.
Ontology merging is an important task in ontology engineering to date. However, despite the efforts devoted to ontology merging, the incorporation of relevant features of ontologies such as axioms, individuals and annotations in the output ontologies remains challenging. Consequently, existing ontology-merging solutions produce new ontologies that do not include all the relevant semantic features from the candidate ontologies. To address these limitations, this paper proposes a novel algorithm for multi-criteria ontology merging that automatically builds a new ontology from candidate ontologies by iteratively updating an RDF graph in the memory. The proposed algorithm leverages state-of-the-art Natural Language Processing tools as well as a Machine Learning-based framework to assess the similarities and merge various criteria into the resulting output ontology. The key contribution of the proposed algorithm lies in its ability to merge relevant features from the candidate ontologies to build a more accurate, integrated and cohesive output ontology. The proposed algorithm is tested with five ontologies of different computing domains and evaluated in terms of its asymptotic behavior, quality and computational performance. The experimental results indicate that the proposed algorithm produces output ontologies that meet the integrity, accuracy and cohesion quality criteria better than related studies. This performance demonstrates the effectiveness and superior capabilities of the proposed algorithm. Furthermore, the proposed algorithm enables iterative in-memory update and building of the RDF graph of the resulting output ontology, which enhances the processing speed and improves the computational efficiency, making it an ideal solution for big data applications. Full article
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24 pages, 7483 KB  
Article
An Approach to Implementing High-Performance Computing for Problem Solving in Workflow-Based Energy Infrastructure Resilience Studies
by Alexander Feoktistov, Alexei Edelev, Andrei Tchernykh, Sergey Gorsky, Olga Basharina and Evgeniy Fereferov
Computation 2023, 11(12), 243; https://doi.org/10.3390/computation11120243 - 4 Dec 2023
Cited by 5 | Viewed by 3048
Abstract
Implementing high-performance computing (HPC) to solve problems in energy infrastructure resilience research in a heterogeneous environment based on an in-memory data grid (IMDG) presents a challenge to workflow management systems. Large-scale energy infrastructure research needs multi-variant planning and tools to allocate and dispatch [...] Read more.
Implementing high-performance computing (HPC) to solve problems in energy infrastructure resilience research in a heterogeneous environment based on an in-memory data grid (IMDG) presents a challenge to workflow management systems. Large-scale energy infrastructure research needs multi-variant planning and tools to allocate and dispatch distributed computing resources that pool together to let applications share data, taking into account the subject domain specificity, resource characteristics, and quotas for resource use. To that end, we propose an approach to implement HPC-based resilience analysis using our Orlando Tools (OT) framework. To dynamically scale computing resources, we provide their integration with the relevant software, identifying key application parameters that can have a significant impact on the amount of data processed and the amount of resources required. We automate the startup of the IMDG cluster to execute workflows. To demonstrate the advantage of our solution, we apply it to evaluate the resilience of the existing energy infrastructure model. Compared to similar approaches, our solution allows us to investigate large infrastructures by modeling multiple simultaneous failures of different types of elements down to the number of network elements. In terms of task and resource utilization efficiency, we achieve almost linear speedup as the number of nodes of each resource increases. Full article
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23 pages, 6014 KB  
Article
Improving NoSQL Spatial-Query Processing with Server-Side In-Memory R*-Tree Indexes for Spatial Vector Data
by Lele Sun and Baoxuan Jin
Sustainability 2023, 15(3), 2442; https://doi.org/10.3390/su15032442 - 30 Jan 2023
Cited by 3 | Viewed by 4603
Abstract
Geospatial databases are basic tools to collect, index, and manage georeferenced data indicators in sustainability research for efficient, long-term analysis. NoSQL databases are increasingly applied to manage the ever-growing massive spatial vector data (SVD) with their changeable data schemas, agile scalability, and fast [...] Read more.
Geospatial databases are basic tools to collect, index, and manage georeferenced data indicators in sustainability research for efficient, long-term analysis. NoSQL databases are increasingly applied to manage the ever-growing massive spatial vector data (SVD) with their changeable data schemas, agile scalability, and fast query response time. Spatial queries are basic operations in geospatial databases. According to Green information technology, an efficient spatial index can accelerate query processing and save power consumption for ubiquitous spatial applications. Current solutions tend to pursue it by indexing spatial objects with space-filling curves or geohash on NoSQL databases. As for the performance-wise R-tree family, they are mainly used in slow disk-based spatial access methods on NoSQL databases that incur high loading and searching costs. Therefore, performing spatial queries efficiently with the R-tree family on NoSQL databases remains a challenge. In this paper, an in-memory balanced and distributed R*-tree index named the BDRST index is proposed and implemented on HBase for efficient spatial-query processing of massive SVD. The BDRST index stores and distributes serialized R*-trees to HBase regions in association with SVD partitions in the same table. Moreover, an efficient optimized server-side parallel processing framework is presented for real-time R*-tree instantiation and query processing. Through extensive experiments on real-world land-use data sets, the performance of our method is tested, including index building, index quality, spatial queries, and applications. Our proposed method outperforms other state-of-the-art solutions, saving between 27.36% and 95.94% on average execution time for the above operations. Experimental results show the capability of the BDRST index to support spatial queries over large-scale SVD, and our method provides a solution for efficient sustainability research that involves massive georeferenced data. Full article
(This article belongs to the Special Issue Geographic Information Science for the Sustainable Development)
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11 pages, 2132 KB  
Brief Report
Brief Report on the Advanced Use of Prolog for Data Warehouses
by François Pinet
Appl. Sci. 2022, 12(21), 11223; https://doi.org/10.3390/app122111223 - 5 Nov 2022
Viewed by 2639
Abstract
Data warehouses have demonstrated their applicability in numerous application fields such as agriculture, the environment and health. This paper proposes a general framework for defining a data warehouse and its aggregations using logic programming. The objective is to show that data managers can [...] Read more.
Data warehouses have demonstrated their applicability in numerous application fields such as agriculture, the environment and health. This paper proposes a general framework for defining a data warehouse and its aggregations using logic programming. The objective is to show that data managers can easily express, in Prolog, traditional data warehouse queries and combine data aggregation operations with other advanced Prolog features. It is shown that this language provides advanced features to aggregate information in an in-memory database. This paper targets data managers; it shows them the direct writing of data warehouse queries in Prolog using an easily understandable syntax. The queries are not necessarily in an optimal form from a processing point of view, but a data manager can easily use or write them. Full article
(This article belongs to the Section Computing and Artificial Intelligence)
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21 pages, 3080 KB  
Article
RISC-Vlim, a RISC-V Framework for Logic-in-Memory Architectures
by Andrea Coluccio, Antonia Ieva, Fabrizio Riente, Massimo Ruo Roch, Marco Ottavi and Marco Vacca
Electronics 2022, 11(19), 2990; https://doi.org/10.3390/electronics11192990 - 21 Sep 2022
Cited by 5 | Viewed by 22122
Abstract
Most modern CPU architectures are based on the von Neumann principle, where memory and processing units are separate entities. Although processing unit performance has improved over the years, memory capacity has not followed the same trend, creating a performance gap between them. This [...] Read more.
Most modern CPU architectures are based on the von Neumann principle, where memory and processing units are separate entities. Although processing unit performance has improved over the years, memory capacity has not followed the same trend, creating a performance gap between them. This problem is known as the "memory wall" and severely limits the performance of a microprocessor. One of the most promising solutions is the "logic-in-memory" approach. It consists of merging memory and logic units, enabling data to be processed directly inside the memory itself. Here we propose an RISC-V framework that supports logic-in-memory operations. We substitute data memory with a circuit capable of storing data and of performing in-memory computation. The framework is based on a standard memory interface, so different logic-in-memory architectures can be inserted inside the microprocessor, based both on CMOS and emerging technologies. The main advantage of this framework is the possibility of comparing the performance of different logic-in-memory solutions on code execution. We demonstrate the effectiveness of the framework using a CMOS volatile memory and a memory based on a new emerging technology, racetrack logic. The results demonstrate an improvement in algorithm execution speed and a reduction in energy consumption. Full article
(This article belongs to the Special Issue Feature Papers in Computer Science & Engineering)
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16 pages, 5816 KB  
Article
Structural Assessment of Interfaces in Projected Phase-Change Memory
by Valeria Bragaglia, Vara Prasad Jonnalagadda, Marilyne Sousa, Syed Ghazi Sarwat, Benedikt Kersting and Abu Sebastian
Nanomaterials 2022, 12(10), 1702; https://doi.org/10.3390/nano12101702 - 17 May 2022
Cited by 2 | Viewed by 2859
Abstract
Non-volatile memories based on phase-change materials have gained ground for applications in analog in-memory computing. Nonetheless, non-idealities inherent to the material result in device resistance variations that impair the achievable numerical precision. Projected-type phase-change memory devices reduce these non-idealities. In a projected phase-change [...] Read more.
Non-volatile memories based on phase-change materials have gained ground for applications in analog in-memory computing. Nonetheless, non-idealities inherent to the material result in device resistance variations that impair the achievable numerical precision. Projected-type phase-change memory devices reduce these non-idealities. In a projected phase-change memory, the phase-change storage mechanism is decoupled from the information retrieval process by using projection of the phase-change material’s phase configuration onto a projection liner. It has been suggested that the interface resistance between the phase-change material and the projection liner is an important parameter that dictates the efficacy of the projection. In this work, we establish a metrology framework to assess and understand the relevant structural properties of the interfaces in thin films contained in projected memory devices. Using X-ray reflectivity, X-ray diffraction and transmission electron microscopy, we investigate the quality of the interfaces and the layers’ properties. Using demonstrator examples of Sb and Sb2Te3 phase-change materials, new deposition routes as well as stack designs are proposed to enhance the phase-change material to a projection-liner interface and the robustness of material stacks in the devices. Full article
(This article belongs to the Special Issue Synthesis, Properties and Applications of Germanium Chalcogenides)
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22 pages, 6057 KB  
Article
An Efficient Spark-Based Hybrid Frequent Itemset Mining Algorithm for Big Data
by Mohamed Reda Al-Bana, Marwa Salah Farhan and Nermin Abdelhakim Othman
Data 2022, 7(1), 11; https://doi.org/10.3390/data7010011 - 14 Jan 2022
Cited by 20 | Viewed by 8389
Abstract
Frequent itemset mining (FIM) is a common approach for discovering hidden frequent patterns from transactional databases used in prediction, association rules, classification, etc. Apriori is an FIM elementary algorithm with iterative nature used to find the frequent itemsets. Apriori is used to scan [...] Read more.
Frequent itemset mining (FIM) is a common approach for discovering hidden frequent patterns from transactional databases used in prediction, association rules, classification, etc. Apriori is an FIM elementary algorithm with iterative nature used to find the frequent itemsets. Apriori is used to scan the dataset multiple times to generate big frequent itemsets with different cardinalities. Apriori performance descends when data gets bigger due to the multiple dataset scan to extract the frequent itemsets. Eclat is a scalable version of the Apriori algorithm that utilizes a vertical layout. The vertical layout has many advantages; it helps to solve the problem of multiple datasets scanning and has information that helps to find each itemset support. In a vertical layout, itemset support can be achieved by intersecting transaction ids (tidset/tids) and pruning irrelevant itemsets. However, when tids become too big for memory, it affects algorithms efficiency. In this paper, we introduce SHFIM (spark-based hybrid frequent itemset mining), which is a three-phase algorithm that utilizes both horizontal and vertical layout diffset instead of tidset to keep track of the differences between transaction ids rather than the intersections. Moreover, some improvements are developed to decrease the number of candidate itemsets. SHFIM is implemented and tested over the Spark framework, which utilizes the RDD (resilient distributed datasets) concept and in-memory processing that tackles MapReduce framework problem. We compared the SHFIM performance with Spark-based Eclat and dEclat algorithms for the four benchmark datasets. Experimental results proved that SHFIM outperforms Eclat and dEclat Spark-based algorithms in both dense and sparse datasets in terms of execution time. Full article
(This article belongs to the Special Issue Knowledge Extraction from Data Using Machine Learning)
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