548 results on '"Volatile memory"'
Search Results
2. A Comprehensive Literature Review on Volatile Memory Forensics.
- Author
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Hamid, Ishrag and Rahman, M. M. Hafizur
- Subjects
LITERATURE reviews ,DIGITAL forensics ,TECHNOLOGICAL innovations ,FORENSIC sciences ,CYBERTERRORISM - Abstract
Through a systematic literature review, which is considered the most comprehensive way to analyze the field of memory forensics, this paper investigates its development through past and current methodologies, as well as future trends. This paper systematically starts with an introduction to the key issues and a notable agenda of the research questions. Appropriate inclusion and exclusion criteria were then developed, and a deliberate search strategy was adopted to identify primary research studies aligned with the research question. The paper goes into specific details of six different memory categories, notably volatile memory, interpreting their advantages and the tactics used to retrieve the data. A detailed comparison with existing reviews and other relevant papers is made, forming a broader and wider picture of the research. The discussion summarizes the main findings, particularly the rise of more complex and advanced cyber threats and the necessity of more effective forensic methods for their investigation. This review pinpoints the possibilities for future study with the purpose of staying ahead in the evolving technological landscape. This overview is undoubtedly an essential resource for professionals and researchers working in digital forensics. It allows them to stay competent and provides enough insight into the current trends while marking the future direction in digital forensics methodology. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Memory
- Author
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LaMeres, Brock J. and LaMeres, Brock J.
- Published
- 2024
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- View/download PDF
4. Modeling Memory
- Author
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LaMeres, Brock J. and LaMeres, Brock J.
- Published
- 2024
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- View/download PDF
5. Biomembrane‐Based Memcapacitive Reservoir Computing System for Energy‐Efficient Temporal Data Processing.
- Author
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Hossain, Md Razuan, Mohamed, Ahmed Salah, Armendarez, Nicholas X., Najem, Joseph S., and Hasan, Md Sakib
- Subjects
ELECTRONIC data processing ,COMPUTER systems ,REAL-time computing ,PROCESS capability ,NONLINEAR regression ,ARTIFICIAL membranes - Abstract
Reservoir computing is a highly efficient machine learning framework for processing temporal data by extracting input features and mapping them into higher dimensional spaces. Physical reservoirs have been realized using spintronic oscillators, atomic switch networks, volatile memristors, etc. However, these devices are intrinsically energy‐dissipative due to their resistive nature, increasing their power consumption. Therefore, memcapacitive devices can provide a more energy‐efficient approach. Herein, volatile biomembrane‐based memcapacitors are leveraged as reservoirs to solve classification tasks and process time series in simulation and experimentally. This system achieves a 99.6% accuracy for spoken‐digit classification and a normalized mean square error of 7.81×10−4$7.81 \times \left(10\right)^{- 4}$ in a second‐order nonlinear regression task. Furthermore, to showcase the device's real‐time temporal data processing capability, a 100% accuracy for an epilepsy detection problem is achieved. Most importantly, it is demonstrated that each memcapacitor consumes an average of 41.5 fJ of energy per spike, regardless of the selected input voltage pulse width, while maintaining an average power of 415 fW for a pulse width of 100 ms, orders of magnitude lower than those achieved by state‐of‐the‐art devices. Lastly, it is believed that the biocompatible, soft nature of our memcapacitor renders it highly suitable for computing applications in biological environments. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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6. Proton‐Conducting Hierarchical Composite Hydrogels Producing First Soft Memcapacitors with Switchable Memory.
- Author
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Biswas, Arnab, Das, Bikash, Pal, Pulak, Ghosh, Aswini, and Chattopadhyay, Nitin
- Subjects
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PROTON conductivity , *CONGO red (Staining dye) , *COMPOSITE structures , *CLEAN energy , *STRUCTURAL models , *HYDROGELS , *MICELLES - Abstract
Perpetual exigency for environment friendly clean energy and powerful soft electronics has elevated the research on hydrogels in past two decades. Hydrogels are the amplifiers of material properties using manipulation in structure–property relationship via simple, economic yet effective routes. Herein, a set of composite and hybrid hydrogels are developed by hierarchical assembling of clay nanosheets and surfactant micelles those divulge the first example of memcapacitor gels and offer exceptional proton conductivity (1.66–4.34 × 10–2 S cm−1) as a gel material. Further, Congo red, Eosin Y, and Orange G are used to hybridize one of the composites to achieve three hybrid hydrogels. Such hybridization is found to regulate the memristive function selectively from the coupled effect of memcapacitance from the composite. The composite hydrogel highlights its volatile memory with encouraging robustness under environmental conditions, established through various current–voltage (I–V) experiments. The electrochemical behaviors including the high proton conductivity are realized from impedance measurements. Material characterizations, experimental results, and in silico optimized structures rationalize composite/hybrid network formation, capacitive/memristive responses, and enhanced proton conduction in the fabricated composite superstructures. Proposed structural models demonstrate two orthogonally oriented structural encryptions to be accountable for the expressed bifunctionality in the hierarchically designed superstructures. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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- View/download PDF
7. The Evolution of Volatile Memory Forensics
- Author
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Hannah Nyholm, Kristine Monteith, Seth Lyles, Micaela Gallegos, Mark DeSantis, John Donaldson, and Claire Taylor
- Subjects
memory dump ,memory acquisition ,memory forensics ,volatile memory ,cyber forensics ,malware identification ,Technology (General) ,T1-995 - Abstract
The collection and analysis of volatile memory is a vibrant area of research in the cybersecurity community. The ever-evolving and growing threat landscape is trending towards fileless malware, which avoids traditional detection but can be found by examining a system’s random access memory (RAM). Additionally, volatile memory analysis offers great insight into other malicious vectors. It contains fragments of encrypted files’ contents, as well as lists of running processes, imported modules, and network connections, all of which are difficult or impossible to extract from the file system. For these compelling reasons, recent research efforts have focused on the collection of memory snapshots and methods to analyze them for the presence of malware. However, to the best of our knowledge, no current reviews or surveys exist that systematize the research on both memory acquisition and analysis. We fill that gap with this novel survey by exploring the state-of-the-art tools and techniques for volatile memory acquisition and analysis for malware identification. For memory acquisition methods, we explore the trade-offs many techniques make between snapshot quality, performance overhead, and security. For memory analysis, we examined the traditional forensic methods used, including signature-based methods, dynamic methods performed in a sandbox environment, as well as machine learning-based approaches. We summarize the currently available tools, and suggest areas for more research.
- Published
- 2022
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8. TEA-RC: Thread Context-Aware Register Cache for GPUs
- Author
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Ipoom Jeong, Yunho Oh, Won Woo Ro, and Myung Kuk Yoon
- Subjects
Graphics processing units ,register file ,register cache ,volatile memory ,non-volatile memory ,hybrid register file ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Graphics processing units (GPUs) achieve high throughput by exploiting a high degree of thread-level parallelism (TLP). To support such high TLP, GPUs have a large-sized register file to store the context of all threads, consuming around 20% of total GPU energy. Several previous studies have attempted to minimize the energy consumption of the register file by implementing an emerging non-volatile memory (NVM), leveraging its higher density and lower leakage power over SRAMs. To amortize the cost of long access latency of NVM, prior work adopts a hierarchical register file consisting of an SRAM-based register cache and NVM-based registers where the register cache works as a write buffer. To get the register cache index, they use the partially selected bits of warp ID and register ID. This work observes that such an index calculation causes three types of contentions leading to the underutilization of the register cache: inter-warp, intra-warp, and false contentions. To minimize such contentions, this paper proposes a thread context-aware register cache (TEA-RC) in GPUs. In TEA-RC, the cache index is calculated considering the high correlation between the number of scheduled threads and the register usage of threads. The proposed design shows 28.5% higher performance and 9.1 percentage point lower energy consumption over the conventional register cache that concatenates three bits of warp ID and five bits of register ID to compute the cache index.
- Published
- 2022
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9. Volatile Memory Disk Forensics: Investigate the Criminal Activity of RAMDisk
- Author
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Mistry, Nilay, Christian, Annan, Bhavsar, Bansari, Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Tuba, Milan, editor, Akashe, Shyam, editor, and Joshi, Amit, editor
- Published
- 2021
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10. The Evolution of Volatile Memory Forensics.
- Author
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Nyholm, Hannah, Monteith, Kristine, Lyles, Seth, Gallegos, Micaela, DeSantis, Mark, Donaldson, John, and Taylor, Claire
- Subjects
INTERNET security ,MALWARE ,MACHINE learning ,RANDOM access memory ,SANDBOXES (Computer science) - Abstract
The collection and analysis of volatile memory is a vibrant area of research in the cybersecurity community. The ever-evolving and growing threat landscape is trending towards fileless malware, which avoids traditional detection but can be found by examining a system's random access memory (RAM). Additionally, volatile memory analysis offers great insight into other malicious vectors. It contains fragments of encrypted files' contents, as well as lists of running processes, imported modules, and network connections, all of which are difficult or impossible to extract from the file system. For these compelling reasons, recent research efforts have focused on the collection of memory snapshots and methods to analyze them for the presence of malware. However, to the best of our knowledge, no current reviews or surveys exist that systematize the research on both memory acquisition and analysis. We fill that gap with this novel survey by exploring the state-of-the-art tools and techniques for volatile memory acquisition and analysis for malware identification. For memory acquisition methods, we explore the trade-offs many techniques make between snapshot quality, performance overhead, and security. For memory analysis, we examined the traditional forensic methods used, including signature-based methods, dynamic methods performed in a sandbox environment, as well as machine learning-based approaches. We summarize the currently available tools, and suggest areas for more research. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
11. Process based volatile memory forensics for ransomware detection.
- Author
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Arfeen, Asad, Asim Khan, Muhammad, Zafar, Obad, and Ahsan, Usama
- Subjects
FEATURE extraction ,RANSOMWARE ,FORENSIC sciences ,BANKING industry ,MEMORY ,BEHAVIORAL assessment - Abstract
Ransomware is an emerging category of malware that locks computer data via powerful cryptographic algorithms. The global propagation of ransomware is a serious threat for individuals and organizations. The banking sector and financial institutions are the prime targets of such ransomware attacks. In case of such an attack, the field of digital forensics helps in estimation of the severity and data loss caused by the attack. Traditional digital forensics investigations make use of static or behavioral analysis to detect malware in infected systems. However, these procedures are challenged by malware obfuscation techniques. Malicious processes can stay inactive and undetected if only a single memory dump is analyzed. Thus, there is a need to collect numerous memory dumps of an individual program that can help with comprehensive and accurate analysis. In this article, we have developed a framework for volatile memory acquisition at regular time intervals to analyze the behavior of individual processes in memory. Through memory forensics, salient features are extracted from the infected memory dumps. These features can be utilized to classify malicious and benign processes efficiently through machine learning as compared to conventional techniques. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
12. Windows Physical Memory Analysis to Detect the Presence of Malicious Code
- Author
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Patil, Dinesh N., Meshram, Bandu B., Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Sa, Pankaj Kumar, editor, Bakshi, Sambit, editor, Hatzilygeroudis, Ioannis K., editor, and Sahoo, Manmath Narayan, editor
- Published
- 2019
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13. Forensics Data Recovery of Skype Communication from Physical Memory
- Author
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Ghafarian, Ahmad, Wood, Charlie, Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Arai, Kohei, editor, Kapoor, Supriya, editor, and Bhatia, Rahul, editor
- Published
- 2019
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- View/download PDF
14. An Organic Optoelectronic Synapse with Multilevel Memory Enabled by Gate Modulation.
- Author
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Guo H, Guo J, Wang Y, Wang H, Cheng S, Wang Z, Miao Q, and Xu X
- Abstract
Artificial synaptic devices are emerging as contenders for next-generation computing systems due to their combined advantages of self-adaptive learning mechanisms, high parallel computation capabilities, adjustable memory level, and energy efficiency. Optoelectronic devices are particularly notable for their responsiveness to both voltage inputs and light exposure, making them attractive for dynamic modulation. However, engineering devices with reconfigurable synaptic plasticity and multilevel memory within a singular configuration present a fundamental challenge. Here, we have established an organic transistor-based synaptic device that exhibits both volatile and nonvolatile memory characteristics, modulated through gate voltage together with light stimuli. Our device demonstrates a range of synaptic behaviors, including both short/long-term plasticity (STP and LTP) as well as STP-LTP transitions. Further, as an encoding unit, it delivers exceptional read current levels, achieving a program/erase current ratio exceeding 10
5 , with excellent repeatability. Additionally, a prototype 4 × 4 matrix demonstrates potential in practical neuromorphic systems, showing capabilities in the perception, processing, and memory retention of image inputs.- Published
- 2024
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15. An effective ransomware detection approach in a cloud environment using volatile memory features
- Author
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Prachi and Kumar, Sumit
- Published
- 2022
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16. Switching Dynamics of Ag-Based Filamentary Volatile Resistive Switching Devices—Part II: Mechanism and Modeling.
- Author
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Wang, Wei, Covi, Erika, Lin, Yu-Hsuan, Ambrosi, Elia, Milozzi, Alessandro, Sbandati, Caterina, Farronato, Matteo, and Ielmini, Daniele
- Subjects
- *
RANDOM access memory , *NONVOLATILE random-access memory , *IONIC mobility , *SHORT-term memory , *RF values (Chromatography) , *ELECTRIC fields - Abstract
Understanding the switching mechanism of the volatile resistive switching random access memory (RRAM) device is important to harness its characteristics and further enhance its performance. Accurate modeling of its dynamic behavior is also of deep value for its applications both as selector and as short-term memory synapse for future neuromorphic applications operating in temporal domain. In this work, we investigate the switching and retention (relaxation) processes of the Ag-based metallic filamentary volatile resistive switching devices. We find that the switching process can be modeled by the ionic drift under electric field, while the retention process can be modeled by the ionic diffusion along the filament surface driven by the gradient of surface atomic concentration. Through further theoretical analysis, we also find that the ionic drift and ionic diffusion can be unified within the general Einstein relation. To confirm this relation, we collect ionic mobility and diffusivity data from the literature using the switching and retention model. Finally, we show that the read voltage dependent retention time can be explained by the competition between the ionic drift and diffusion flux. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
17. Schematic Processing inWorking Memory TasksRelies on Learning and Long-Term Memory Resources
- Author
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Noori, Nader
- Subjects
Working Memory ,Symbolic Working Memory ,Volatile Memory ,Long-term Memory ,Concurrent-counting ,Schematic Access - Abstract
This paper presents an evidence for involvement of long-termmemory (LTM) resources along volatile memory (VM) resourcesin active management of information in a workingmemory (WM) task that features schematic processing ofWMcontent. It was observed that in rehearsing frequently changingWM items in a self-paced concurrent-counting task whensubjects learn and use a fixed rehearsing order across differentepisodes of the task they make significantly less error comparedto when they adopt different rehearsing order for differentepisodes. This finding suggests that while retaining informationin this task practically draws on volatile resourcessuch as the phonological loop (PL), access to the correspondingitem in WM relies on learning and retaining data structuresin LTM. It is discussed that in this role learning and LTMresources help render schematic access to episodic informationstored in less structured storage units such as PL. In thisrole LTM and learning plays a crucial role in execution ofWMtasks that employ complex process schemas.
- Published
- 2015
18. The SymbolicWorking Memory:memory accommodations for schematic processing of symbolic information
- Author
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Noori, Nader
- Subjects
Symbolic Working Memory ,Volatile Memory ,StateRegistry System ,Working Memory ,Selective Access - Abstract
This paper describes an evolutionarily plausible description of ofa specialized working memory system involved in informationmanagement for high-order cognitive tasks through its capabilityfor controlled maintenance and schematic access to symbolic representations.Along a volatile serially accessible symbolic storagethat serves a basic maintenance function the system utilizesother accessory volatile memory systems along long-term memory(LTM) and learning systems for execution of schematic accessto its content. Accessory systems can help encode the episodicinformation including the current state of the task and more importantlyprovide a means for address-based access to the contentof symbolic storage. LTM and learning systems help map the currentstate of the task onto execution programs and thus help renderschematic access and process of the retained symbolic information.Implications of this feature of the model are examined forthe case if concurrent-counting task.
- Published
- 2015
19. Functional Applications of Future Data Storage Devices.
- Author
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Yang, Jia‐Qin, Zhou, Ye, and Han, Su‐Ting
- Subjects
DATA warehousing ,ARTIFICIAL intelligence ,PHASE change memory ,COMPLEMENTARY metal oxide semiconductors ,COMPUTER systems ,RANDOM access memory ,FLASH memory - Abstract
The development of artificial intelligence and big data analytics is driving a revolution in methods for data processing and storage. Confronting speed and energy consumption issues, these fields require new computing systems to parallelly retrieve, process, and store massive amounts of data. Beyond CMOS devices and technology, advances in data storage technology such as static random‐access memory, dynamic random‐access memory, flash memories, resistive memories, phase change memories, and magnetic memories have made functional computing possible. In this article, a broad overview of current memory systems and their development history spanning fundamental operating schemes, prevailing applications and required figure of merits for applications such as in‐memory computing and some critical issues that need to be addressed in the future development of this emerging technique are provided. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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20. Challenges in Android Forensics
- Author
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Hazra, Sudip, Mateti, Prabhaker, Barbosa, Simone Diniz Junqueira, Series editor, Chen, Phoebe, Series editor, Filipe, Joaquim, Series editor, Kotenko, Igor, Series editor, Sivalingam, Krishna M., Series editor, Washio, Takashi, Series editor, Yuan, Junsong, Series editor, Zhou, Lizhu, Series editor, Thampi, Sabu M., editor, Martínez Pérez, Gregorio, editor, Westphall, Carlos Becker, editor, Hu, Jiankun, editor, Fan, Chun I., editor, and Gómez Mármol, Félix, editor
- Published
- 2017
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21. Chain-of-Trust for Microcontrollers using SRAM PUFs: the Linux Case Study
- Author
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Amelino, Domenico, Barbareschi, Mario, Mazzeo, Antonino, Xhafa, Fatos, Series editor, Barolli, Leonard, editor, and Amato, Flora, editor
- Published
- 2017
- Full Text
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22. Thermochromic Color Switching to Temperature Controlled Volatile Memory and Counter Operations with Metal–Organic Complexes and Hybrid Gels.
- Author
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Nirmala, Anjali, Mukkatt, Indulekha, Shankar, Sreejith, and Ajayaghosh, Ayyappanpillai
- Subjects
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TEMPERATURE control , *COLOR temperature , *CHEMICAL systems , *MEMORY , *STIMULUS & response (Psychology) , *THERMORESPONSIVE polymers - Abstract
Temperature is often not considered as a precision stimulus for artificial chemical systems in contrast to the host–guest interactions related to many natural processes. Similarly, mimicking multi‐state volatile memory operations using a single molecular system with temperature as a precision stimulus is highly laborious. Here we demonstrate how a mixture of iron(II) chloride and bipyridine can be used as a reversible color‐to‐colorless thermochromic switch and logic operators. The generality of the approach was illustrated using CoII and NiII salts that resulted in color‐to‐color transitions. DMSO gels of these systems, exhibited reversible opaque‐transparency switching. More importantly, optically readable multi‐state volatile memory with temperature as a precision input has been demonstrated. The stored data is volatile and is lost instantaneously upon withdrawal or change of temperature. Simultaneous read‐out at multiple wavelengths results in single‐input/multi‐output sequential logic operations such as data accumulators (counters) leading to volatile memory states. The present system provides access to thermoresponsive materials wherein temperature can be used as a precision stimulus. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
23. Brain-Inspired Reservoir Computing Using Memristors with Tunable Dynamics and Short-Term Plasticity.
- Author
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Armendarez NX, Mohamed AS, Dhungel A, Hossain MR, Hasan MS, and Najem JS
- Abstract
Recent advancements in reservoir computing (RC) research have created a demand for analogue devices with dynamics that can facilitate the physical implementation of reservoirs, promising faster information processing while consuming less energy and occupying a smaller area footprint. Studies have demonstrated that dynamic memristors, with nonlinear and short-term memory dynamics, are excellent candidates as information-processing devices or reservoirs for temporal classification and prediction tasks. Previous implementations relied on nominally identical memristors that applied the same nonlinear transformation to the input data, which is not enough to achieve a rich state space. To address this limitation, researchers either diversified the data encoding across multiple memristors or harnessed the stochastic device-to-device variability among the memristors. However, this approach requires additional preprocessing steps and leads to synchronization issues. Instead, it is preferable to encode the data once and pass them through a reservoir layer consisting of memristors with distinct dynamics. Here, we demonstrate that ion-channel-based memristors with voltage-dependent dynamics can be controllably and predictively tuned through the voltage or adjustment of the ion channel concentration to exhibit diverse dynamic properties. We show, through experiments and simulations, that reservoir layers constructed with a small number of distinct memristors exhibit significantly higher predictive and classification accuracies with a single data encoding. We found that for a second-order nonlinear dynamical system prediction task, the varied memristor reservoir experimentally achieved an impressive normalized mean square error of 1.5 × 10
-3 , using only five distinct memristors. Moreover, in a neural activity classification task, a reservoir of just three distinct memristors experimentally attained an accuracy of 96.5%. This work lays the foundation for next-generation physical RC systems that can exploit the complex dynamics of their diverse building blocks to achieve increased signal processing capabilities.- Published
- 2024
- Full Text
- View/download PDF
24. Light Memory Operation Based on a Double Pin SiC Device
- Author
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Silva, V., Barata, M., Vieira, M. A., Louro, P., Vieira, M., Rannenberg, Kai, Editor-in-chief, Sakarovitch, Jacques, Series editor, Goedicke, Michael, Series editor, Tatnall, Arthur, Series editor, Neuhold, Erich J., Series editor, Pras, Aiko, Series editor, Tröltzsch, Fredi, Series editor, Pries-Heje, Jan, Series editor, Whitehouse, Diane, Series editor, Reis, Ricardo, Series editor, Murayama, Yuko, Series editor, Dillon, Tharam, Series editor, Gulliksen, Jan, Series editor, Rauterberg, Matthias, Series editor, Camarinha-Matos, Luis M., editor, Baldissera, Thais A., editor, Di Orio, Giovanni, editor, and Marques, Francisco, editor
- Published
- 2015
- Full Text
- View/download PDF
25. Frugal discrete memristive device based on potassium permanganate solution
- Author
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Chetan C Revadekar, Ashkan Vakilipour Takaloo, Sandeep P Shinde, Swapnil R Patil, Somnath S Kundale, Deok-kee Kim, and Tukaram D Dongale
- Subjects
memristor ,memristive switching ,discrete device ,volatile memory ,electrochemistry ,electrochemical impendence spectroscopy ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Chemical technology ,TP1-1185 - Abstract
Many thin film-based devices with solid electrolytes have been studied for memristive applications. Herein, we report a simple and facile way to fabricate solution-based, low-cost, and discrete two-terminal memristive devices using the KMnO _4 solution. The water and methanol were used as a solvent to prepare different concentrations of KMnO _4 to carry out the optimization study. Furthermore, the effect of KMnO _4 concentration with aqueous and methanol solvents was studied with the help of current-voltage, device charge, charge-flux, and cyclic endurance properties. Interestingly, all developed devices show the asymmetric time-domain charge and double valued charge-flux properties, suggesting that aqueous KMnO _4 and methanol-KMnO _4 based devices are non-ideal memristors or memristive devices. The statistical measures such as cumulative probability and coefficient of variation are reported for the memristive devices. The possible switching mechanism of the discrete memristive was tried to explain with the UV-visible spectrum and theoretical framework. The optimized device was further studied using the cyclic voltammogram, Bode plot, and Nyquist plot. An equivalent circuit was derived for the optimized discrete memristive device using electrochemical impendence spectroscopy results. The results of the present investigation are beneficial to develop programmable analog circuits, volatile memory, and synaptic devices using discrete memristive devices.
- Published
- 2021
- Full Text
- View/download PDF
26. Nonvolatile and Volatile Memory Characteristics of a Silicon Nanowire Feedback Field-Effect Transistor With a Nitride Charge-Storage Layer.
- Author
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Kang, Hyungu, Cho, Jinsun, Kim, Yoonjoong, Lim, Doohyeok, Woo, Sola, Cho, Kyoungah, and Kim, Sangsig
- Subjects
- *
NONVOLATILE memory , *FIELD-effect transistors , *SILICON nanowires , *NITRIDES , *ELECTRONIC feedback , *THRESHOLD voltage - Abstract
We demonstrate the nonvolatile and volatile memory characteristics of a gate-all-around silicon nanowire feedback field-effect transistor (FBFET) with a nitride charge-storage layer analyzed by a commercial TCAD simulator. Our FBFET exhibits a threshold voltage window of 0.76 V with a programming/erasing time of ${1}~\mu \text{s}$ in the nonvolatile memory mode. We investigated the delay of read operations with accumulated charges in the intrinsic channel region in this memory mode. Moreover, the FBFET exhibits a sensing margin of 6.3 $\mu \text{A}$ and a read/write speed of 10 ns with an outstanding retention time, as well as nondestructive read characteristics in the volatile memory mode, allowing this device to operate without any refresh operation. In addition, we describe the operating principle of our device and demonstrate its potential as integrated memory for 3-D integrations. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
27. Study of an interesting physical mechanism of memory effect in nematic liquid crystal dispersed with quantum dots.
- Author
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Rastogi, Ayushi, Agrahari, Kaushlendra, Pathak, Govind, Srivastava, Atul, Herman, Jakub, and Manohar, Rajiv
- Subjects
- *
NEMATIC liquid crystals , *QUANTUM dot synthesis , *QUANTUM dots , *LIQUID crystals , *ION traps , *MEMORY - Abstract
The present study is based on effect of dispersing Cd1−xZnxS/ZnS core/shell quantum dots (QDs) on the memory behaviour of nematic liquid crystal 2020 with the variation of dopant concentration and applied voltage. Around 26% and 45% memory storage in QDs dispersed nematic matrix (MIX 1 and MIX 2) has been the core finding. The presence of ionic charges at low-frequency regime along with their reduction in QDs dispersed nematic matrix has been confirmed from tan δ curve. Pure nematic LC as well as nematic/QD mixtures depict volatile memory effect that depends upon concentration of QDs. The existence of memory due to storage of charge on QDs has been further confirmed from the dielectric, polarising optical micrographs and electro optical study under the influence of bias voltage. The observation of memory effect is attributed to the ion capturing and ion releasing phenomenon. The dispersion of QDs in nematic material plays an important role to enhance memory parameter by capturing and releasing the ionic charges under the application of bias voltage which has been confirmed from capacitance-voltage curve. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
28. Thorough Understanding of Retention Time of Z2FET Memory Operation.
- Author
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Duan, M., Navarro, C., Cheng, B., Adamu-Lema, F., Wang, X., Georgiev, V. P., Gamiz, F., Millar, C., and Asenov, A.
- Subjects
- *
RF values (Chromatography) , *DYNAMIC random access memory , *IMPACT ionization , *BIOELECTROCHEMISTRY , *ELECTRON sources - Abstract
A recently reported zero impact ionization and zero subthreshold swing device Z2FET is a promising candidate for capacitor-less dynamic random access memory (DRAM) memory cell. In the memory operation, data retention time determines refresh frequency and is one of the most important memory merits. In this paper, we have systematically investigated the Z2FET retention time based on a newly proposed characterization methodology. It is found that the degradation of HOLD “0” retention time originates from the gated-silicon on insulator (SOI) portion rather than the intrinsic-SOI region of the Z2FET. Electrons accumulate under front gate and finally collapse the potential barrier turning logic “0”–“1.” It appears that Shockley–Read–Hall (SRH) generation is the main source for electrons accumulation. Z2FET scalability has been investigated in terms of retention time. As the Z2FET is downscaled, the mechanism dominating electrons accumulation switches from SRH to parasitic injection of electrons from the cathode. The results show that the downscaling of Lg has little effect on data “0” retention, but Lin is limited to ~125 nm. An optimization method of the fabrication process is proposed based on this new understanding, and Lin can be further scaled down to 75 nm. We have demonstrated by 2-D TCAD simulation that Z2FET is a promising DRAM cells’ candidate particularly for Internet-of-Things applications. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
29. HEART: <u>H</u> ybrid Memory and <u>E</u> nergy- <u>A</u> ware <u>R</u> eal- <u>T</u> ime Scheduling for Multi-Processor Systems
- Author
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Christian Hakert, Jian-Jia Chen, Mario Günzel, and Kuan-Hsun Chen
- Subjects
business.industry ,Computer science ,Hibernation (computing) ,Energy consumption ,Scheduling (computing) ,Idle ,Shared memory ,Hardware and Architecture ,Embedded system ,State (computer science) ,business ,Software ,Volatile memory ,Efficient energy use - Abstract
Dynamic power management (DPM) reduces the power consumption of a computing system when it idles, by switching the system into a low power state for hibernation. When all processors in the system share the same component, e.g., a shared memory, powering off this component during hibernation is only possible when all processors idle at the same time. For a real-time system, the schedulability property has to be guaranteed on every processor, especially if idle intervals are considered to be actively introduced. In this work, we consider real-time systems with hybrid shared-memory architectures, which consist of shared volatile memory (VM) and non-volatile memory (NVM). Energy-efficient execution is achieved by applying DPM to turn off all memories during the hibernation mode. Towards this, we first explore the hybrid memory architectures and suggest a task model, which features configurable hibernation overheads. We propose a multi-processor procrastination algorithm (HEART), based on partitioned earliest-deadline-first (pEDF) scheduling. Our algorithm facilitates reducing the energy consumption by actively enlarging the hibernation time. It enforces all processors to idle simultaneously without violating the schedulability condition, such that the system can enter the hibernation state, where shared memories are turned off. Throughout extensive evaluation of HEART, we demonstrate (1) the increase in potential hibernation time, respectively the decrease in energy consumption, and (2) that our algorithm is not only more general but also has better performance than the state of the art with respect to energy efficiency in most cases.
- Published
- 2021
30. Malware: The Never-Ending Arm Race
- Author
-
Héctor D. Menéndez
- Subjects
Cover (telecommunications) ,Computer science ,business.industry ,Compromise ,media_common.quotation_subject ,Representation (arts) ,computer.software_genre ,Computer security ,Race (biology) ,Software ,Malware ,business ,computer ,Vice president ,Volatile memory ,media_common - Abstract
"Antivirus is death"' and probably every detection system that focuses on a single strategy for indicators of compromise. This famous quote that Brian Dye --Symantec's senior vice president-- stated in 2014 is the best representation of the current situation with malware detection and mitigation. Concealment strategies evolved significantly during the last years, not just like the classical ones based on polimorphic and metamorphic methodologies, which killed the signature-based detection that antiviruses use, but also the capabilities to fileless malware, i.e. malware only resident in volatile memory that makes every disk analysis senseless. This review provides a historical background of different concealment strategies introduced to protect malicious --and not necessarily malicious-- software from different detection or analysis techniques. It will cover binary, static and dynamic analysis, and also new strategies based on machine learning from both perspectives, the attackers and the defenders.
- Published
- 2021
31. Switching Dynamics of Ag-Based Filamentary Volatile Resistive Switching Devices—Part II: Mechanism and Modeling
- Author
-
Matteo Farronato, Elia Ambrosi, Daniele Ielmini, Caterina Sbandati, Alessandro Milozzi, Yu-Hsuan Lin, Wei Wang, and Erika Covi
- Subjects
Threshold voltage ,Materials science ,Ionic bonding ,02 engineering and technology ,01 natural sciences ,Ion ,Mathematical model ,Electric field ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,Electrodes ,Ions ,010302 applied physics ,Surface diffusion ,Data models ,020206 networking & telecommunications ,surface diffusion ,Electronic, Optical and Magnetic Materials ,Resistive random-access memory ,Chemical physics ,Voltage control ,Einstein relation ,ionic drift ,volatile memory ,Switches ,Voltage ,Volatile memory - Abstract
Understanding the switching mechanism of the volatile resistive switching random access memory (RRAM) device is important to harness its characteristics and further enhance its performance. Accurate modeling of its dynamic behavior is also of deep value for its applications both as selector and as short-term memory synapse for future neuromorphic applications operating in temporal domain. In this work, we investigate the switching and retention (relaxation) processes of the Ag-based metallic filamentary volatile resistive switching devices. We find that the switching process can be modeled by the ionic drift under electric field, while the retention process can be modeled by the ionic diffusion along the filament surface driven by the gradient of surface atomic concentration. Through further theoretical analysis, we also find that the ionic drift and ionic diffusion can be unified within the general Einstein relation. To confirm this relation, we collect ionic mobility and diffusivity data from the literature using the switching and retention model. Finally, we show that the read voltage dependent retention time can be explained by the competition between the ionic drift and diffusion flux.
- Published
- 2021
32. Persistent software transactional memory in Haskell
- Author
-
Nicolas Krauter, Sebastian Erdweg, Peter J. Braam, André Brinkmann, Reza Salkhordeh, and Patrick Raaf
- Subjects
Computer science ,Programming language ,computer.software_genre ,Runtime system ,Software portability ,Memory management ,Software transactional memory ,Haskell ,Persistent data structure ,Safety, Risk, Reliability and Quality ,computer ,Software ,Garbage collection ,computer.programming_language ,Volatile memory - Abstract
Emerging persistent memory in commodity hardware allows byte-granular accesses to persistent state at memory speeds. However, to prevent inconsistent state in persistent memory due to unexpected system failures, different write-semantics are required compared to volatile memory. Transaction-based library solutions for persistent memory facilitate the atomic modification of persistent data in languages where memory is explicitly managed by the programmer, such as C/C++. For languages that provide extended capabilities like automatic memory management, a more native integration into the language is needed to maintain the high level of memory abstraction. It is shown in this paper how persistent software transactional memory (PSTM) can be tightly integrated into the runtime system of Haskell to atomically manage values of persistent transactional data types. PSTM has a clear interface and semantics extending that of software transactional memory (STM). Its integration with the language’s memory management retains features like garbage collection and allocation strategies, and is fully compatible with Haskell's lazy execution model. Our PSTM implementation demonstrates competitive performance with low level libraries and trivial portability of existing STM libraries to PSTM. The implementation allows further interesting use cases, such as persistent memoization and persistent Haskell expressions.
- Published
- 2021
33. RRAM for Compute-in-Memory: From Inference to Training
- Author
-
Yandong Luo, Shimeng Yu, Xiaochen Peng, and Wonbo Shim
- Subjects
Computer science ,020208 electrical & electronic engineering ,Inference ,02 engineering and technology ,Resistive random-access memory ,Computer architecture ,Scalability ,0202 electrical engineering, electronic engineering, information engineering ,Benchmark (computing) ,Hardware acceleration ,Electrical and Electronic Engineering ,Inference engine ,Throughput (business) ,Volatile memory - Abstract
To efficiently deploy machine learning applications to the edge, compute-in-memory (CIM) based hardware accelerator is a promising solution with improved throughput and energy efficiency. Instant-on inference is further enabled by emerging non-volatile memory technologies such as resistive random access memory (RRAM). This paper reviews the recent progresses of the RRAM based CIM accelerator design. First, the multilevel states RRAM characteristics are measured from a test vehicle to examine the key device properties for inference. Second, a benchmark is performed to study the scalability of the RRAM CIM inference engine and the feasibility towards monolithic 3D integration that stacks RRAM arrays on top of advanced logic process node. Third, grand challenges associated with in-situ training are presented. To support accurate and fast in-situ training and enable subsequent inference in an integrated platform, a hybrid precision synapse that combines RRAM with volatile memory (e.g. capacitor) is designed and evaluated at system-level. Prospects and future research needs are discussed.
- Published
- 2021
34. Online Social Snapshots of a Generic Facebook Session Based on Digital Insight Data for a Secure Future IT Environment
- Author
-
Hai-Cheng Chu and Jong Hyuk Park
- Subjects
online social networking (OSN) ,Facebook ,social networking site (SNS) ,cyberspace security forensics ,volatile memory ,Mathematics ,QA1-939 - Abstract
Physical memory acquisition has been an import facet for digital forensics (DF) specialists due to its volatile characteristics. Nowadays, thousands of millions of global participants utilize online social networking (OSN) mechanisms to expand their social lives, ranging from business-oriented purposes to leisure motivations. Facebook (FB) is one of the most dominant social networking sites (SNS) available today. Unfortunately, it has been a major avenue for cybercriminals to commit illegal activities. Therefore, the digital traces of previous sessions of an FB user play an essential role as the first step for DF experts to pursue the disclosure of the identity of the suspect who was exploiting FB. In this research work, we provide a systematic methodology to reveal a previous session of an FB identity, as well as his/her partial social circle via collecting, analyzing, preserving and presenting the associated digital traces to obtain the online social snapshots of a specific FB user who was utilizing a computing device with Internet Explorer (IE) 10 without turning off the power of the gadget. This novel approach can be a paradigm for how DF specialists ponder the crime scene to conduct the first response in order to avoid the permanent loss of the precious digital evidence in previous FB sessions. The hash values of the image files of the random access memory (RAM) of the computing device have proven to be identical before and after forensics operations, which could be probative evidence in a court of law.
- Published
- 2015
- Full Text
- View/download PDF
35. Improving Message Logging Protocols Scalability through Distributed Event Logging
- Author
-
Ropars, Thomas, Morin, Christine, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, D’Ambra, Pasqua, editor, Guarracino, Mario, editor, and Talia, Domenico, editor
- Published
- 2010
- Full Text
- View/download PDF
36. Trusted system-calls analysis methodology aimed at detection of compromised virtual machines using sequential mining.
- Author
-
Nissim, Nir, Lapidot, Yuval, Cohen, Aviad, and Elovici, Yuval
- Subjects
- *
CLOUD computing , *VIRTUAL machine systems , *SEQUENTIAL analysis , *CYBERTERRORISM , *ANTIVIRUS software - Abstract
Most organizations today employ cloud-computing environments and virtualization technology; Due to their prevalence and importance in providing services to the entire organization, virtual-servers are constantly targeted by cyber-attacks, and specifically by malware. Existing solutions, consisting of the widely-used antivirus (AV) software, fail to detect newly created and unknown-malware; moreover, by the time the AV is updated, the organization has already been attacked. In this paper, we present a during run-time analysis methodology for a trusted detection of unknown malware on virtual machines (VMs). We conducted trusted analysis of volatile memory dumps taken from a VM and focused on analyzing their system-calls using a sequential-mining-method. We leveraged the most informative system-calls by machine-learning algorithms for the efficient detection of malware in widely used VMs within organizations (i.e. IIS and Email server). We evaluated our methodology in a comprehensive set of experiments over a collections of real-world, advanced, and notorious malware (both ransomware and RAT), and legitimate programs. The results show that our suggested methodology is able to detect the presence of unknown malware, in an average of 97.9% TPR and 0% FPR. Such results and capabilities can form the ground for the development of practical detection-tools for both corporates and companies. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
37. Nanostructured Fused Pyrrole Thin Films: Encoding Nano “Bits” with Temporary Remanence.
- Author
-
Canjeevaram Balasubramanyam, Ram Kumar, Kandjani, Ahmad E., Jones, Lathe A., Periasamy, Selvakannan R., Wong, Sherman, Narayan, Ramanuj, Bhargava, Suresh K., Ippolito, Samuel J., and Basak, Pratyay
- Subjects
THIN films ,PYRROLE derivatives ,ATOMIC force microscopes ,CHARGE transfer ,NANOSTRUCTURED materials - Abstract
Abstract: A comprehensive understanding of resistive switching phenomenon and its dependence on molecular structure is imperative for enhancing the consistency and reliability of organic resistive memory (ORM) devices. Here, the efforts are directed to establish a premise for providing detailed insights into the molecular property, thin film assembly, and digital memory performance of a 1,4‐dihydropyrrolo[3,2‐b]pyrrole (DHPP) derivative. The fabricated devices display switching characteristics with an I
ON/OFF ratio of ≈105 , howbeit, with a “temporary remanence” of ≈2 min. The ON state can be sustained under a constant electrical duress of −1 V and can be repeatedly reprogrammed for >110 cycles. Conductive atomic force microscope (C‐AFM) studies demonstrate that the thin film can be electrically written to a “0” or “1” state under extremely low compliance currents of ±250 pA with an appreciable ON/OFF ratio of 102 . Conservative estimates for the switching area of ≈150 nm2 with energy as low as 15 fJ to induce a switching event underscore the possibility of nanoscale data storage with high areal density. The role of charge transfer interactions during the OFF to ON transitions and the origin of volatile memory behaviour are further elucidated in conjunction with electrochemical impedance studies (EIS) and theoretical simulations. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
38. Trusted detection of ransomware in a private cloud using machine learning methods leveraging meta-features from volatile memory.
- Author
-
Cohen, Aviad and Nissim, Nir
- Subjects
- *
RANSOMWARE , *CLOUD computing , *MACHINE learning , *INFORMATION technology , *INFRASTRUCTURE (Economics) - Abstract
Cloud computing is one of today's most popular and important IT trends. Currently, most organizations use cloud computing services (public or private) as part of their computer infrastructure. Virtualization technology is at the core of cloud computing, and virtual resources, such as virtual servers, are commonly used to provide services to the entire organization. Due to their importance and prevalence, virtual servers in an organizational cloud are constantly targeted by cyber-attackers who try to inject malicious code or malware into the server (e.g., ransomware). Many times, server administrators are not aware that the server has been compromised, despite the presence of detection solutions on the server (e.g., antivirus engine). In other cases, the breach is detected after a long period of time when significant damage has already occurred. Thus, detecting that a virtual server has been compromised is extremely important for organizational security. Existing security solutions that are installed on the server (e.g., antivirus) are considered untrusted, since malware (particularly sophisticated ones) can evade them. Moreover, these tools are largely incapable of detecting new unknown malware. Machine learning (ML) methods have been shown to be effective at detecting malware in various domains. In this paper, we present a novel methodology for trusted detection of ransomware in virtual servers on an organization's private cloud. We conducted trusted analysis of volatile memory dumps taken from a virtual machine (memory forensics), using the Volatility framework, and created general descriptive meta-features. We leveraged these meta-features, using machine learning algorithms, for the detection of unknown ransomware in virtual servers. We evaluated our methodology extensively in five comprehensive experiments of increasing difficulty, on two different popular servers (IIS server and an email server). We used a collection of real-world, professional, and notorious ransomware and a collection of legitimate programs. The results show that our methodology is able to detect anomalous states of a virtual machine, as well as the presence of both known and unknown ransomware, obtaining the following results: TPR = 1, FPR = 0.052, F-measure = 0.976, and AUC = 0.966, using the Random Forest classifier. Finally, we showed that our proposed methodology is also capable of detecting an additional type of malware known as a remote access Trojan (RAT), which is used to attack organizational VMs. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
39. On Using the Volatile Mem-Capacitive Effect of TiO Resistive Random Access Memory to Mimic the Synaptic Forgetting Process.
- Author
-
Sarkar, Biplab, Mills, Steven, Lee, Bongmook, Pitts, W., Misra, Veena, and Franzon, Paul
- Subjects
TITANIUM oxides ,METAL oxide semiconductors ,NONVOLATILE random-access memory ,DIELECTRICS ,CAPACITORS - Abstract
In this work, we report on mimicking the synaptic forgetting process using the volatile mem-capacitive effect of a resistive random access memory (RRAM). TiO dielectric, which is known to show volatile memory operations due to migration of inherent oxygen vacancies, was used to achieve the volatile mem-capacitive effect. By placing the volatile RRAM candidate along with SiO at the gate of a MOS capacitor, a volatile capacitance change resembling the forgetting nature of a human brain is demonstrated. Furthermore, the memory operation in the MOS capacitor does not require a current flow through the gate dielectric indicating the feasibility of obtaining low power memory operations. Thus, the mem-capacitive effect of volatile RRAM candidates can be attractive to the future neuromorphic systems for implementing the forgetting process of a human brain. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
40. Enhancement of Transient Two-States Characteristics in Metal-Insulator-Semiconductor Structure by Thinning Metal Thickness.
- Author
-
Tseng, Kuan-Hao, Liao, Chien-Shun, and Hwu, Jenn-Gwo
- Abstract
In this work, the Al/SiO2/p-Si metal-insulator-semiconductor structures with various metal thicknesses were fabricated. The charging/discharging transient current behaviors during sweeping or switching the voltages have been studied. By thinning down partial portion of the gate metal to 10 nm, the steady state leakage current was found decreased because the high resistivity of the ultrathin metal causing lower fringing field effect. Also, the transient currents were found enhanced. The reasons were that there were minority carriers under the ultrathin metal contributing to the transient currents. The above properties make the device having better volatile memory characteristics. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
- View/download PDF
41. Flexible multi-level quasi-volatile memory based on organic vertical transistor
- Author
-
Huipeng Chen, Qian Yang, Lihua He, Tailiang Guo, Xiaomin Wu, Changsong Gao, Huihuang Yang, Liuting Shan, and Xianghong Zhang
- Subjects
Dynamic random-access memory ,Hardware_MEMORYSTRUCTURES ,business.industry ,Computer science ,Bandwidth (signal processing) ,Transistor ,Electrical engineering ,Cloud computing ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,law.invention ,Power (physics) ,law ,Universal memory ,General Materials Science ,Electrical and Electronic Engineering ,Data retention ,0210 nano-technology ,business ,Volatile memory - Abstract
Driven by important megatrends such as cloud computing, artificial intelligence, and the Internet of Things, as a device used to store programs and data in computing systems, memory is struggling to catch up with the explosive growth of data and bandwidth requirements in the system. However, the “storage wall” between non-volatile memory and volatile memory retards the further improvement of modern memory computing systems. Herein, a quasi-volatile transistor memory based on organic polymer/perovskite quantum dot blend was fabricated using the vertical transistor configuration. Contributing to vertical structure and appropriate doping ratio of blend film, the quasi-volatile memory device displayed 1,560 times longer data retention time (> 100 s) with respect to the dynamic random access memory and fast data programming speed (20 µs) in which was far more quickly than that of other organic non-volatile memories to fill the gap between volatile and non-volatile memories. Moreover, the device retention characteristics could be further promoted under the photoelectric synergistic stimulation, which also provided the possibility to reduce electric writing condition. Furthermore, the quasi-volatile memory device showed good electrical performance under bending conditions. This work provides a simple solution to fabricate multi-level quasi-volatile memory, which opens up a whole new avenue of “universal memory” and lays a solid foundation for low power and flexible random access memory devices.
- Published
- 2021
42. Volatile and Nonvolatile Memory Operations Implemented in a Pt/HfO₂/Ti Memristor
- Author
-
Lei Wu, Hongxia Liu, Shulong Wang, and Jinfu Lin
- Subjects
010302 applied physics ,Materials science ,business.industry ,Memristor ,Trapping ,Plasticity ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,law.invention ,Non-volatile memory ,Rectification ,law ,0103 physical sciences ,Electrode ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Volatile memory ,Voltage - Abstract
Both nonvolatile and volatile characteristics are realized in the same Pt/HfO2/Ti memristor by specific electrical operations. The resistance states of nonvolatile memory hardly change for over 105 s, whereas the low resistance state of volatile memory is unstable, and degenerates gradually into the high resistance state in hundreds of seconds. The volatile device was forming-free and realized only in clockwise voltage sweeping. Compared to the nonvolatile device, the operating current of volatile device was lower and showed obviously rectification characteristics. Emulations of synaptic plasticity including short-term plasticity, long-term plasticity, and spike-time-dependent-plasticity were achieved. Finally, the resistive switching mechanism of the volatile device was analyzed and assumed to be the trapping and detrapping of electrons by traps near the interface of Pt/HfO2.
- Published
- 2021
43. Noble gas incorporation into silicate glasses: implications for planetary volatile storage
- Author
-
Arianna Gleason, Sergey N. Tkachev, Wendy L. Mao, R. Jeanloz, B. Chen, and H. Yang
- Subjects
Materials science ,Chemical engineering ,Geochemistry and Petrology ,Environmental Chemistry ,Geology ,Noble gas (data page) ,Silicate glass ,Volatile memory - Published
- 2021
44. FORENSICS ANALYSIS OF PRIVACY OF PORTABLE WEB BROWSERS.
- Author
-
Ghafarian, Ahmad
- Abstract
Web browser vendors offer a portable web browser option which is considered as one of the features that provides user privacy. Portable web browser is a browser that can be launched from a USB flash drive without the need for its installation on the host machine. Most popular web browsers have portable versions of their browsers as well. Portable web browsing poses a great challenge to computer forensic investigators who try to reconstruct the past browsing history, in case of any computer incidence. This research examines various sources in the host machine such as physical memory, temporary, recent, event files, Windows Registry, and Cache.dll files for the evidential information regarding portable browsing session. The portable browsers under this study include Firefox, Chrome, Safari, and Opera. Results of this experiment show that portable web browsers do not provide user-privacy as they are expected to do. [ABSTRACT FROM AUTHOR]
- Published
- 2016
45. Strain Analysis in Submicron Electron Devices by Convergent Beam Electron Diffraction
- Author
-
Armigliato, A., Balboni, R., Frabboni, S., Benedetti, A., Cullis, A. G., Beig, R., editor, Englert, B. -G., editor, Frisch, U., editor, Hänggi, P., editor, Hepp, K., editor, Hillebrandt, W., editor, Imboden, D., editor, Jaffe, R. L., editor, Lipowsky, R., editor, v. Löhneysen, H., editor, Ojima, I., editor, Sornette, D., editor, Theisen, S., editor, Weise, W., editor, Wess, J., editor, Zittartz, J., editor, Watanabe, Yoshio, editor, Salviati, Giancarlo, editor, Heun, Stefan, editor, and Yamamoto, Naoki, editor
- Published
- 2002
- Full Text
- View/download PDF
46. Spray-Coated, Volatile and Nonvolatile, Two-Terminal, Resistive Switching Memory Devices Comprising Liquid-Exfoliated Black Phosphorus and Graphene Layers
- Author
-
Christos D. Dimitrakopoulos and Yooyeon Jo
- Subjects
010302 applied physics ,Hardware_MEMORYSTRUCTURES ,Materials science ,business.industry ,Reading (computer) ,01 natural sciences ,Flash memory ,Electronic, Optical and Magnetic Materials ,Resistive random-access memory ,Non-volatile memory ,0103 physical sciences ,Electrode ,Optoelectronics ,Static random-access memory ,Electrical and Electronic Engineering ,Thin film ,business ,Volatile memory - Abstract
Resistive switching memory devices fabricated with black phosphorus inks showed volatile memory device characteristics, specifically static random access memory (SRAM) and bipolar resistive switching. A high ON-/OFF -current ratio of $6.5\times 10^{{7}}$ was obtained at a reading voltage of 0.5 V with good retention stability (over 104 s). Multilevel data storage performance under different compliance currents was demonstrated. Importantly, a nonvolatile memory device was also fabricated, using an ink that comprised thinner, on average, black phosphorus flakes with a narrower thickness distribution than the ink used in the above described devices. The nonvolatile memory device showed good write/erase operation, like flash memory, during 100 endurance cycles, and good retention stability with $1.9\times 10^{{3}}$ of on/off ratio at 0.5 V. According to these results, we suggest that thin films of liquid-exfoliated black phosphorus deposited by spray coating are suitable for low-cost, solution-processed, two-terminal resistive memory devices, either volatile or nonvolatile ones, the memory device type being controlled by the details of the ink preparation process, and the resulting flake thickness distributions.
- Published
- 2020
47. Thermochromic Color Switching to Temperature Controlled Volatile Memory and Counter Operations with Metal–Organic Complexes and Hybrid Gels
- Author
-
Ayyappanpillai Ajayaghosh, Indulekha Mukkatt, Sreejith Shankar, and Anjali Nirmala
- Subjects
Thermochromism ,Materials science ,Sequential logic ,010405 organic chemistry ,General Medicine ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Chloride ,Catalysis ,0104 chemical sciences ,Metal ,Bipyridine ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Natural processes ,visual_art ,medicine ,visual_art.visual_art_medium ,AND gate ,Volatile memory ,medicine.drug - Abstract
Temperature is often not considered as a precision stimulus for artificial chemical systems in contrast to the host-guest interactions related to many natural processes. Similarly, mimicking multi-state volatile memory operations using a single molecular system with temperature as a precision stimulus is highly laborious. Here we demonstrate how a mixture of iron(II) chloride and bipyridine can be used as a reversible color-to-colorless thermochromic switch and logic operators. The generality of the approach was illustrated using CoII and NiII salts that resulted in color-to-color transitions. DMSO gels of these systems, exhibited reversible opaque-transparency switching. More importantly, optically readable multi-state volatile memory with temperature as a precision input has been demonstrated. The stored data is volatile and is lost instantaneously upon withdrawal or change of temperature. Simultaneous read-out at multiple wavelengths results in single-input/multi-output sequential logic operations such as data accumulators (counters) leading to volatile memory states. The present system provides access to thermoresponsive materials wherein temperature can be used as a precision stimulus.
- Published
- 2020
48. Obtaining forensic value from the cbWndExtra structures as used by Windows Common Controls, specifically for the Editbox control.
- Author
-
Bridge, Adam
- Subjects
COMPUTER crimes ,CRIMINAL investigation ,COMPUTER storage devices ,GRAPHICAL user interfaces ,WINDOWS (Graphical user interfaces) - Abstract
The Windows Common Controls is a library which facilitates the construction of GUI controls commonly used by Windows applications. Each control is an extension of the basic ‘window’ class. The difference in the extension results in one control over another; for example, an Edit control as opposed to a Button control. The basic window class is documented by Microsoft and the generic information about a Window can be extracted, but this is of very limited use. There is no documentation and very little research into how these extensions are laid out in memory. This paper demonstrates how the extension bytes for the Edit control can be parsed leading to identification of previously unobtainable data which reveal information about the state of the control at runtime. Most notably, the undo buffer, that is, text that was previously present in the control can be recovered – an aspect which traditional disk forensics would simply not provide. The paper explains why previous attempts to achieve similar goals have failed, and how the technique could be applied to any control from the Windows Common Controls library. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
49. Pirate Card Rejection
- Author
-
Goldschlag, David M., Kravitz, David W., Goos, Gerhard, editor, Hartmanis, Juris, editor, van Leeuwen, Jan, editor, Quisquater, Jean-Jacques, editor, and Schneier, Bruce, editor
- Published
- 2000
- Full Text
- View/download PDF
50. Crab-tree
- Author
-
Gunavaran Brihadiswarn, Chundong Wang, and Sudipta Chattopadhyay
- Subjects
010302 applied physics ,CPU cache ,Computer science ,Copy-on-write ,02 engineering and technology ,Parallel computing ,01 natural sciences ,020202 computer hardware & architecture ,B-tree ,Non-volatile memory ,Tree (data structure) ,Hardware and Architecture ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Overhead (computing) ,Cache ,Software ,Volatile memory - Abstract
In recent years, the next-generation non-volatile memory (NVM) technologies have emerged with DRAM-like byte addressability and disk-like durability. Computer architects have proposed to use them to build persistent memory that blurs the conventional boundary between volatile memory and non-volatile storage. However, ARM processors, ones that are widely used in embedded computing systems, start providing architectural supports to utilize NVM since ARMv8. In this article, we consider tailoring B+-tree for NVM operated by a 64-bit ARMv8 processor. We first conduct an empirical study of performance overhead in writing and reading data for a B+-tree with an ARMv8 processor, including the time cost of cache line flushes and memory fences for crash consistency as well as the execution time of binary search compared to that of linear search. We hence identify the key weaknesses in the design of B+-tree with ARMv8 architecture. Accordingly, we develop a new B+-tree variant, namely, c rash r ecoverable A RMv8-oriented B +-tree (Crab-tree). To insert and delete data at runtime, Crab-tree selectively chooses one of two strategies, i.e., copy on write and shifting in place, depending on which one causes less consistency cost. Crab-tree regulates a strict execution order in both strategies and recovers the tree structure in case of crashes. To further improve the performance of Crab-tree, we employ three methods to reduce software overhead, cache misses, and consistency cost, respectively. We have implemented and evaluated Crab-tree in Raspberry Pi 3 Model B+ with emulated NVM. Experiments show that Crab-tree significantly outperforms state-of-the-art B+-trees designed for persistent memory by up to 2.2× and 3.7× in write and read performances, respectively, with both consistency and scalability achieved.
- Published
- 2020
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