Physical Memory Research Articles

Efficiently Enlarging RDMA-Attached Memory with SSD

RDMA-based in-memory storage systems offer high performance but are restricted by the capacity of physical memory. In this paper, we propose TeRM to extend RDMA-attached memory with SSD. TeRM achieves fast remote access on the SSD-extended memory by eliminating page faults of RDMA NIC and CPU from the critical path. We also introduce a set of techniques to reduce the consumption of CPU and network resources. Evaluation shows that TeRM performs close to the performance of the ideal upper bound where all pages are pinned in the physical memory. Compared with existing approaches TeRM significantly improves the performance of unmodified RDMA-based storage systems, including a file system and a key-value system.

MIC: Memory analysis of IndexedDB data on Chromium-based applications

As Chromium-based applications continue to gain popularity, it is necessary for forensic investigators to obtain a comprehensive understanding of how they store and manage browsing artifacts from both filesystem and memory perspectives. In particular, the incognito mode developed in the current version of Chromium uses only physical memory to manage data related to active sessions. Therefore, handling physical memory is essential for tracking a user's browsing behaviour in incognito mode. This paper provides an in-depth examination of LevelDB, a lightweight key-value database utilized as Chromium's implementation for IndexedDB. In particular, we delve into the details of how IndexedDB data is managed through LevelDB, taking into account its low-level database file format. Furthermore, we thoroughly explore the possibility of residual data, both complete and incomplete, being retained as applications create and initialize IndexedDB-related data. Based on our research findings, we propose a systematic methodology for inspecting the internal structures of LevelDB-related C++ classes, carving these structures from binary streams, and interpreting the data for forensic analysis. In addition, we develop a proof-of-concept tool based on our approach and demonstrate its performance and effectiveness through case studies.

Volatile data acquisition and analysis by using Memory Forensics techniques

Memory forensics is a vital component of digital investigations, involving the analysis of volatile memory (RAM) in computer systems to gather evidence, identify malicious activities, and reconstruct cybercrime incidents. This paper provides an overview of memory forensics, highlighting its definition, importance, purpose, and scope. It explores the evolution and significance of memory forensics in response to increasingly complex cyber threats. The memory forensics process is discussed, covering memory acquisition and analysis. Legal and ethical considerations related to the admissibility of memory evidence and privacy protection are examined. The paper also discusses the types of memory, including physical and virtual memory, and their characteristics and significance in memory forensics. Furthermore, it explores the memory acquisition process, different methods, tools, and techniques used, as well as the importance of preserving evidence integrity. Finally, the paper introduces various tools for memory analysis, such as Volatility, Volatility Workbench, FTK Imager, Encase, Hibernation Recon, and Xplico, and highlights their role in extracting valuable evidence from memory dumps.

TRACking health behavior in people with multiple sclerosis: Effects of a randomized trial on physical activity and working memory.

Multiple sclerosis is associated with impairments in working memory functioning. Lifestyle physical activity interventions show promise in improving cognitive functioning; however, the evidence is limited. We examined the efficacy of a lifestyle physical activity intervention, involving step tracking and psychoeducational materials, on improving step counts, working memory functioning, and network strength in a whole-brain network of working memory. Participants (n = 75) were randomly assigned to a group tracking steps with a pedometer (step-track), or a group tracking water intake with a smart water bottle (water-track), for 6 months. At baseline, mid, and postintervention, we assessed weekly physical activity (GT3X+ accelerometer), weekly water intake (H20 Pal Smart Bottle), and working memory functioning. Additionally, the combined network strength of a validated working memory connectome was calculated. We ran random intercept linear mixed models to examine differences between the groups, over time. A significant Group × Time interaction effect with steps and water intake indicated that the step-track group increased their steps, and the water-track group increased their water intake, in comparison to each other, from baseline to postintervention (p < .05). Both groups improved in behavioral working memory over time (p < .05). No significant differences were found on the network strength. Our 6-month randomized controlled trial involving physical activity tracking showed increased step count in the intervention group. Behavioral working memory improved in both groups, potentially due to practice effects. Future studies should include both active and passive control groups to discern practice effects from intervention impact. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Experiential Avoidance Process Model: A Review of the Mechanism for the Generation and Maintenance of Avoidance Behavior.

Experiential avoidance refers to a phenomenon in which individuals exhibit an unwillingness to engage with certain personal experiences, including physical sensations, emotions, thoughts, memories, and behavioral tendencies. They employ cognition and emotions to avoid these experiences. Extensive research has linked experiential avoidance to various mental diseases, conduct disorder, and posttraumatic stress disorder. While the existing literature highlights the significance of understanding experiential avoidance as a central mechanism underlying psychological symptomatology development and maintenance, further investigation is required to comprehend its dimensions and mechanisms fully. Therefore, this article aims to provide a comprehensive review of the current theories and empirical evidence on experiential avoidance while elucidating its association with psychopathology. We propose a model of experiential avoidance processes based on an extensive review and critical analysis of the previous emotion regulation model that integrates expressive suppression and cognitive reappraisal during emotion regulation through experiential avoidance. This proposed model seeks to explain both the formation and maintenance aspects of experiential avoidance by offering valuable insights for future research. We also examined the association between experiential avoidance and various psychiatric disorders, including anxiety, depression, obsessive-compulsive disorder, and posttraumatic stress disorder. Elaborating on these mechanisms provides a roadmap for future research endeavors and clinical interventions.

The association between physical activity and memory interference.

Habitual physical activity has been shown to improve memory performance, yet investigations into its effects concerning memory interference remain limited. Additionally, minimal research has evaluated the association between habitual physical activity behaviors occurring in different contexts (e.g., walking, basketball, swimming) and memory. Based on these gaps in the literature, the present set of six experiments evaluated the association between contextually-different physical activity behaviors (e.g., individual physical activities, physical activities performed in social settings) and memory interference among young adult samples from America and Germany. Across six experiments, we reliably demonstrated that Germans exhibited greater memory performance than Americans. We also reliably demonstrated that contextually-different physical activities are not associated with memory performance or attenuated memory interference.

A study on the correlation between physical fitness index and executive function in Chinese adolescents

Objective To explore the relationship between physical fitness index and executive function in Chinese adolescents, and to provide a reference for improving the development of executive function in Chinese adolescents. Methods From September to December 2023, 5336 adolescents aged 13 to 18 years were selected by stratified whole cluster random sampling method in six regions of China for physical fitness and executive function tests. The relationship between adolescent physical fitness index and executive function was analyzed using t-test, ANOVA, Pearson’s correlation, and logistic regression. Results The correlation coefficients between adolescents’ physical fitness index and inhibitory control reaction time were all 0.00094, p > 0.05; the correlation coefficients between adolescents’ physical fitness index and working memory (1-back, 2-back) reaction time were −0.13 and −0.093, respectively, p < .05; the correlation coefficients between adolescents’ physical fitness index and cognitive flexibility reaction time were −0.17 and −0.18, p < .05. Logistic regression analyses showed that 1-back, 2-back, and cognitive flexibility were significantly and positively correlated with physical fitness index in Models 1, 2, and 3 (all p values less than.01). The coefficients of inhibitory control were not significant in all three models (p > .05), and there was no significant relationship with physical fitness index. Conclusion The physical fitness index of Chinese adolescents has a significant positive correlation with working memory and cognitive flexibility, but not with inhibitory control, i.e. the higher the physical fitness index, the better the working memory and cognitive flexibility.

An extreme multistable circuit based on a new memcapacitor and a new meminductor

Expanding the definition of memristor gets memcapacitor and meminductor. Because there are very few physical memory elements, it is very meaningful to apply its equivalent model to the study of physical circuits. In this paper, based on the definition of the memory element, a new memcapacitor and a new meminductor are proposed, and a chaotic oscillator circuit is constructed based on them. Whether the two memory elements have memory characteristics is analyzed. The range of equilibrium points of the chaotic oscillator circuit is determined. The dynamical behavior of this chaotic oscillator circuit is analyzed by the Lyapunov exponent spectrum (LEs), bifurcation diagram (BD) and spectral entropy complexity (SE). Finally, Multisim software is used to verify the correctness of the simulation, and the physical realizability of the system is verified by the DSP platform. The results of the research help to better utilize this chaotic oscillator circuit in the field of communication encryption.

In the time loop: Data remanence in main memory of virtual machines

Data remanence in the physical memory of computers, i.e., the fact that data remains temporarily in memory even after power is cut, is a well-known issue which can be exploited for recovering cryptographic keys and other data in forensic investigations. Since virtual machines in many aspects mimic their physical counterparts, we investigate whether data remanence is also observable in virtual machines. Using KVM as an example of virtualization technology, we experimentally show that it is common for a substantial amount of volatile data to remain in the memory of virtual machines after a reboot. In digital forensic analysis scenarios such as malware analysis using virtual machines, our observations imply high risks of evidence contamination if no precautions are taken. So while the symptoms of data remanence in virtual machines are similar to physical machines, the implications for digital forensic analysis appear very different.

Enhancing Big Data Performance Through Graph Coloring-Based Locality of Reference

Efficiency is a crucial factor when handling the retrieval and storage of data from vast amounts of records in a Big Data repository. These systems require a subset of data that can be accommodated within the combined physical memory of a cluster of servers. It becomes impractical to analyze all of the data if its size exceeds the available memory capacity. Retrieving data from virtual storage, primarily hard disks, is significantly slower compared to accessing data from main memory, resulting in increased access time and diminished performance. To address this, a proposed model aims to enhance performance by identifying the most suitable data locality structure within a big data set and reorganizing the data schema accordingly; by locality, it has been referred to as a particular access pattern. This allows transactions to be executed on data residing in the fastest memory layer, such as cache, main memory, or disk cache

Supplementation with stigma maydis polysaccharide attenuates autism-like behaviors and improves gut function in valproic acid-induced autism model male rats.

Stigma maydis polysaccharide (SMPS) has regulatory effect on the intestinal microflora and promotes gastrointestinal peristalsis. Children with autism spectrum disorder (ASD) often experience gastrointestinal problems and dysbiosis in their gut microbiota. Our previous study revealed that SMPS interventions had an impact on the gut microbiota of valproic acid (VPA)-induced autism model rats. However, the effects of SMPS on the behavior and gut function of autism model rats remain poorly understood. Therefore, we gave different doses of SMPS intervention in the early stage of autism model rats to observe their developmental conditions and behavior performances. Through histological evaluation and real-time polymerase chain reaction (PCR), integrity of the intestinal structure and the expression of tight junction-related gene Zo-1 and Occludin were detected. The results indicated that SMPS intervention improved the physical development, learning and memory impairment, and social performance of autism model rats. Meanwhile, SMPS promoted intestinal peristalsis and restored the integrity of the intestinal structure, reduced the number of inflammatory cells, and increased the expression of the Zo-1 and Occludin genes. Furthermore, the expression levels of neurotransmitters (substance P, enkephalin, vasoactive intestinal peptide, and 5-hydroxytryptamine) in the hippocampal tissues were altered after SMPS treatment. In conclusion, SMPS could ameliorate ASD-like phenotypes and gut problems in autism model rats. Collectively, these results provide new evidence for the relationship between the gut-brain axis and ASD and suggest a novel therapeutic target for ASD treatment.

Reduction of long COVID symptoms after stellate ganglion block: A retrospective chart review study

The SARS-CoV-2 pandemic has left millions of individuals with a host of post-viral symptoms that can be debilitating and persist indefinitely. To date there are no definitive tests or treatments for the collection of symptoms known as “Long COVID” or Post-acute sequelae of COVID-19 (PASC). Following our initial case report detailing improvement of Long COVID symptoms after sequential bilateral stellate ganglion blockade (SGB), we performed a retrospective chart analysis study on individuals treated with the same protocol over the course of six months (2021−2022) in our clinic. Patients self-reported symptoms on a 10-point scale as part of optional patient follow-up using an online survey. After one month or more following treatment, patients reported striking reductions in Fatigue, Worsening of Symptoms following Mental and Physical Activity, Memory Problems, Problems Concentrating, Sleep Problems, Anxiety, and Depression. Loss of Taste and Loss of Smell in some individuals did not respond to treatment, likely indicating structural damage following infection. This study suggests that neuromodulation may provide relief of Long COVID symptoms for at least a subset of individuals, and provides support for prospective studies of this potential treatment.

Dignity enhanced through faith & family support in palliative care: a qualitative study

BackgroundDignity is integral to palliative care. Illness can diminish it, causing hopelessness and the wish to hasten death. Yet, dignity is a complex multidimensional phenomenon, influenced by values and context. Understanding its varying interpretations can inform practice and policy. The aim of the study is to explore the understanding of dignity in adult patients with palliative care needs from a Lebanese perspective and how it is preserved during illness and while receiving health services.DesignQualitative interview study underpinned with a social constructionist lens. Fourteen patients recruited from home-based hospice and outpatient clinics in Lebanon. Data analysed using reflexive thematic analysis.ResultsFour themes were developed across all the interviews: (a) Dignity anchored through faith in God and religious practices; (b) Family support in maintaining physical, psychological wellbeing, and social connectedness; (c) Physical fitness, mental acuity, and healthy appearance through which patients may escape the stigma of disease, (d) accessible, equitable, and compassionate healthcare.DiscussionDignity is elusive and difficult to define but faith and religious beliefs play a significant contribution in this study. For the participants, illness is seen as a natural part of life that does not necessarily diminish dignity, but it is the illness related changes that potentially affect dignity. Findings show the importance of family and children in preserving dignity during illness and how their active presence provide a sense of pride and identity. Participants aspired to restore physical, social, and mental well-being to reclaim their dignity and normalize their lives. Challenges related to physical appearance, memory loss, vitality, and social stigma associated with illness diminished dignity. Accessible, equitable and compassionate healthcare services are also crucial in preserving dignity. Participants valued clear communication, respect, and empathy from healthcare providers and identified affordability of care essential for maintaining dignity.ConclusionFaith in God, and strong family ties are dominant elements to maintaining dignity in the Lebanese context. Relational connectedness with family, children or God is also a need in maintaining dignity in other communal countries with variations in emphasis. The study indicates that religious and cultural context shapes the needs and perceptions of dignity during illness. These findings are likely to be transferable to many Middle Eastern countries but also countries with strong religious and family ties globally.

Blitzcrank: Fast Semantic Compression for In-Memory Online Transaction Processing

We present Blitzcrank, a high-speed semantic compressor designed for OLTP databases. Previous solutions are inadequate for compressing row-stores: they suffer from either low compression factor due to a coarse compression granularity or suboptimal performance due to the inefficiency in handling dynamic data sets. To solve these problems, we first propose novel semantic models that support fast inferences and dynamic value set for both discrete and continuous data types. We then introduce a new entropy encoding algorithm, called delayed coding, that achieves significant improvement in the decoding speed compared to modern arithmetic coding implementations. We evaluate Blitzcrank in both standalone microbenchmarks and a multicore in-memory row-store using the TPC-C benchmark. Our results show that Blitzcrank achieves a sub-microsecond latency for decompressing a random tuple while obtaining high compression factors. This leads to an 85% memory reduction in the TPC-C evaluation with a moderate (19%) throughput degradation. For data sets larger than the available physical memory, Blitzcrank help the database sustain a high throughput for more transactions before the I/O overhead dominates.

Advanced Fabrication and Characterization of Hydrothermal Responsive Fabric from Microcrystalline Cellulose-Reinforced Shape Memory Polyurethane Filament

Demands for smart textiles have recently increased quickly in terms of functionality and responsiveness to wearers and environmental changes. This paper explores the development of hydrothermal responsive shape memory woven fabric from Microcrystalline Cellulose Reinforced Shape Memory Polyurethane Microcomposite Filament. The concentration of microcrystalline cellulose and drawing ratio of the filaments were first optimized according to the tensile strength and shape recovery ratio and taken as 15 wt% and 2.0 respectively. Hydrothermal responsive shape memory micro-composite filaments were then produced from shape memory polyurethane (SMPU) and microcrystalline cellulose (MCC) with optimized concentration and draw ratio by wet spinning process. The physical, mechanical, thermal and shape memory performances of the filaments were studied. The optimized filament was found to have a tensile strength of 0.91 cN/dtex and elongation of 385.2% in which the strength is much more improved when compared to a pure SMPU filament of strength 0.72 cN/dtex. The shape fixity and shape recovery results of the micro-composite filament were found to be 71.2% and 93.6% respectively. A woven fabric was manufactured from pure polyester, cotton as warp and SMPU-MCC filaments as weft and its breathability and shape memory properties were investigated. The air permeability of SMPU-PE fabrics was found to be 172.9 mm/s and 155.1 mm/s in its fixed temporary shape and recovered shape respectively. The water vapour permeability of SMPU-CT fabric was found to be 612.01 g/m2.h and 540.28 g/m2.h in its fixed temporary and recovered shape respectively which shows smart breathable fabrics can be made and adopted with enhanced properties.

EPO‐R: An efficient garbage collection scheme for long‐term transactions

SummaryThis article proposes EPO‐R, which is an efficient garbage collection scheme designed for multi‐version concurrency control (MVCC) protocols. MVCC generates a version for each update operation, and it can exhaust physical memory for dynamically changing environments such as IoT payments. Eager pruning of obsolete versions (EPO) is a novel garbage collection technique for long‐term transactions. We found room for improvement in EPO, which triggers reclamation invocation. EPO is triggered for each write operation, and it wastes CPU resources. The proposed method EPO‐R is triggered on a read operation to address this issue. The result of experiments with 64 CPU cores and workloads with the combination of short‐term and long‐term transactions demonstrated that EPO‐R exhibited 6.3 times higher throughput than that of EPO. The reason for this can be explained by analyzing the number of unreclaimable versions.

Interactions between physical exercise, associative memory, and genetic risk for Alzheimer's disease.

The ε4 allele of the APOE gene heightens the risk of late onset Alzheimer's disease. ε4 carriers, may exhibit cognitive and neural changes early on. Given the known memory-enhancing effects of physical exercise, particularly through hippocampal plasticity via endocannabinoid signaling, here we aimed to test whether a single session of physical exercise may benefit memory and underlying neurophysiological processes in young ε3 carriers (ε3/ε4 heterozygotes, risk group) compared with a matched control group (homozygotes for ε3). Participants underwent fMRI while learning picture sequences, followed by cycling or rest before a memory test. Blood samples measured endocannabinoid levels. At the behavioral level, the risk group exhibited poorer associative memory performance, regardless of the exercising condition. At the brain level, the risk group showed increased medial temporal lobe activity during memory retrieval irrespective of exercise (suggesting neural compensatory effects even at baseline), whereas, in the control group, such increase was only detectable after physical exercise. Critically, an exercise-related endocannabinoid increase correlated with task-related hippocampal activation in the control group only. In conclusion, healthy young individuals carrying the ε4 allele may present suboptimal associative memory performance (when compared with homozygote ε3 carriers), together with reduced plasticity (and functional over-compensation) within medial temporal structures.

COMPREHENSIVE PRE-DISCHARGE SYMPTOMS ASSESSMENT IN HYPERTENSIVE PATIENTS HOSPITALIZED FOR COVID-19 ALLOWS TO PREDICT PERSISTENCE OF SYMPTOMS AT 3 MONTHS

Objective: To study the prognostic value of survey-based respiratory, physical, emotional, and cognitive symptoms assessment in hypertensive patients hospitalized for COVID-19 in prediction of symptoms persistence at 3 months after discharge. Design and method: 88 hospitalized patients with COVID-19 and a history of hypertension (mean age 57.8+-11.8 years, 53% female) underwent a comprehensive survey-based symptoms assessment 1-2 days prior to discharge that included MRC Dyspnea scale, CAT and CCQ questionnaires, HADS, the physical symptoms subscale of the EFTER-COVID questionnaire, and the Memory, Thinking, and Communication subscale of the SBQ-LC questionnaire. Marginal effects in logistic regression analysis were used to gauge the predictive value of resulting scores and separate symptoms. 500 SANN-based classification models were subsequently trained for various combinations of significant predictors, with an automatic ranging of obtained models by their predictive accuracy. Results: 77% of participants have reported an incomplete ecovery at 3 month after hospital discharge. In the order of decreasing predictive value for persistence of symptoms, significant (p &lt; 0,05) risk factors included EFTER-COVID physical symptoms score (Somers’ D-statistic = 0,63), HADS depression subscale (D = 0,58), SBQ-LC Memory, Thinking, and Communication score (D = 0,52), MRC dyspnea class (D = 0,45), and CAT score (D = 0,30); among the specific symptoms, significant predictors included dyspnea (D = 0,42), dizziness (D = 0,38), muscles and joints pain (D = 0,38), and difficulties in remembering things (D = 0,40). Out of the derived machine-learning based classification models, the optimal performance was observed for the one using gender, pre-discharge MRC dyspnea class, and summary scores on EFTER-COVID physical symptoms and SBQ-LC Memory, Thinking, and Communication subscales. The model exhibited a 100% predictive acccuracy in classifying the pre-specified test/validation subset of the study group into those who would subsequently report persistence of symptoms or complete recovery. Conclusions: Survey-based pre-discharge assessment of symptoms in hypertensive patients hospitalized for acute COVID-19 yields a high prognostic value. The combination of gender and survey-based measures of dyspnea, physical and cognitive symptoms may be used in this setting to predict the persistence of symptoms at 3 months after hospital discharge.

Volatile Data Acquisition and Analysis by Using Memory Forensics Techniques

Memory forensics is a vital component of digital investigations, involving the analysis of volatile memory (RAM) in computer systems to gather evidence, identify malicious activities, and reconstruct cybercrime incidents. This paper provides an overview of memory forensics, highlighting its defini-tion, importance, purpose, and scope. It explores the evolution and significance of memory forensics in response to increasingly complex cyber threats. The memory forensics process is discussed, cover-ing memory acquisition and analysis. Legal and ethical considerations related to the admissibility of memory evidence and privacy protection are examined. The paper also discusses the types of memory, including physical and virtual memory, and their characteristics and significance in memory forensics. Furthermore, it explores the memory acquisition process, different methods, tools, and techniques used, as well as the importance of preserving evidence integrity. Finally, the paper introduces various tools for memory analysis, such as Volatility, Volatility Workbench, FTK Imager, Encase, Hibernation Recon, and Xplico, and highlights their role in extracting valuable evidence from memory dumps.

NSimplex Zen : A Novel Dimensionality Reduction for Euclidean and Hilbert Spaces

Dimensionality reduction techniques map values from a high dimensional space to one with a lower dimension. The result is a space which requires less physical memory and has a faster distance calculation. These techniques are widely used where required properties of the reduced-dimension space give an acceptable accuracy with respect to the original space. Many such transforms have been described. They have been classified in two main groups: linear and topological . Linear methods such as Principal Component Analysis (PCA) and Random Projection (RP) define matrix-based transforms into a lower dimension of Euclidean space. Topological methods such as Multidimensional Scaling (MDS) attempt to preserve higher-level aspects such as the nearest-neighbour relation, and some may be applied to non-Euclidean spaces. Here, we introduce nSimplex Zen , a novel topological method of reducing dimensionality. Like MDS, it relies only upon pairwise distances measured in the original space. The use of distances, rather than coordinates, allows the technique to be applied to both Euclidean and other Hilbert spaces, including those governed by Cosine, Jensen–Shannon and Quadratic Form distances. We show that in almost all cases, due to geometric properties of high-dimensional spaces, our new technique gives better properties than others, especially with reduction to very low dimensions.