Memory Trade-off Research Articles

Higher post-encoding cortisol benefits the selective consolidation of emotional aspects of memory

Emotional experiences create durable memory traces in the brain, especially when these memories are consolidated in the presence of stress hormones such as cortisol. Although some research suggests cortisol elevation can increase long-term memory for emotional relative to neutral content, the impact of stress and cortisol on the consolidation of emotional and neutral aspects of memories when they are part of the same experience remains unknown. Here, after encoding complex scenes consisting of negative or neutral objects placed on neutral backgrounds, participants were exposed to a psychosocial stressor (or matched control condition) in order to examine the impact of stress and cortisol on early consolidation processes. The next day, once cortisol levels had returned to baseline, specific and gist recognition memory were tested separately for objects and backgrounds. Results indicate that while there was a numerical increase in memory for negative objects in the stress group, higher endogenous cortisol concentrations were specifically associated with decreased memory for the neutral backgrounds originally paired with negative objects. Moreover, across all participants, cortisol levels were positively correlated with the magnitude of the emotional memory trade-off effect. Specifically, while memory for negative objects was preserved, elevated cortisol during early consolidation was associated with decreased memory for neutral backgrounds that were initially paired with negative objects. These memory effects were observed in both the stricter specific measure of memory and the less conservative measure of gist memory. Together, these findings suggest that rather than influencing all aspects of an experience similarly, elevated cortisol during early consolidation selectively preserves what is most emotionally salient and adaptive to remember while allowing the loss of memory for less important neutral information over time.

Approximate Voronoi cells for lattices, revisited

Abstract We revisit the approximate Voronoi cells approach for solving the closest vector problem with preprocessing (CVPP) on high-dimensional lattices, and settle the open problem of Doulgerakis–Laarhoven–De Weger [PQCrypto, 2019] of determining exact asymptotics on the volume of these Voronoi cells under the Gaussian heuristic. As a result, we obtain improved upper bounds on the time complexity of the randomized iterative slicer when using less than 2 0.076 d + o ( d ) $2^{0.076d + o(d)}$ memory, and we show how to obtain time–memory trade-offs even when using less than 2 0.048 d + o ( d ) $2^{0.048d + o(d)}$ memory. We also settle the open problem of obtaining a continuous trade-off between the size of the advice and the query time complexity, as the time complexity with subexponential advice in our approach scales as d d / 2 + o ( d ) $d^{d/2 + o(d)}$ matching worst-case enumeration bounds, and achieving the same asymptotic scaling as average-case enumeration algorithms for the closest vector problem.

The effects of post-stimulus elaboration, background valence, and item salience on the emotion-induced memory trade-off

ABSTRACT The effect of emotion on memory often leads to the trade-off: enhanced memory for emotional items comes at the cost of memory for background information. Although this effect is usually attributed to overt attention during encoding, Steinmetz and Kensinger (2013) proposed that such an effect might also be related to post-stimulus elaboration. Based on previous different viewpoints, we used the directed forgetting paradigm to further explore the effect of post-stimulus elaboration on the memory trade-off. In the meantime, we also tested the roles of background valence and item salience (high salient items were placed in the centre of backgrounds while low salient items were placed in the periphery of backgrounds) in modulating the memory trade-off. Our results showed that there was a memory trade-off when backgrounds were neutral, whereas this was no longer the case when backgrounds were negative. This indicated the memory trade-off might be affected by background valence. Meanwhile, we found post-stimulus elaboration contributed to selective memory enhancement for backgrounds, while item salience enhanced item memory performance in the memory trade-off. These findings suggest the emotion-induced memory trade-off may be a complex memory effect, which can be influenced by different factors to varying degrees.

Affect enhances object-background associations: evidence from behaviour and mathematical modelling

ABSTRACT In recognition memory paradigms, emotional details are often recognised better than neutral ones, but at the cost of memory for peripheral details. We previously provided evidence that, when peripheral details must be recalled using central details as cues, peripheral details from emotional scenes are at least as likely to be recalled as those from neutral scenes. Here we replicated and explicated this result by implementing a mathematical modelling approach to disambiguate the influence of target type, scene emotionality, scene valence, and their interactions. After incidentally encoding scenes that included neutral backgrounds with a positive, negative, or neutral foreground objects, participants showed equal or better cued recall of components from emotional scenes compared to neutral scenes. There was no evidence of emotion-based impairment in cued recall in either of two experiments, including one in which we replicated the emotion-induced memory trade-off in recognition. Mathematical model fits indicated that the emotionality of the encoded scene was the primary driver of improved cued-recall performance. Thus, even when emotion impairs recognition of peripheral components of scenes, it can preserve the ability to recall which scene components were studied together.

Cryptanalytic Time–Memory–Data Trade-offs for FX-Constructions and the Affine Equivalence Problem

The FX-construction was proposed in 1996 by Kilian and Rogaway as a generalization of the DESX scheme. The construction increases the security of an n-bit core block cipher with a $$\kappa $$ -bit key by using two additional n-bit masking keys. Recently, several concrete instances of the FX-construction were proposed, including PRINCE, PRIDE and MANTIS (presented at ASIACRYPT 2012, CRYPTO 2014 and CRYPTO 2016, respectively). In this paper, we devise new cryptanalytic time–memory–data trade-off attacks on FX-constructions. By fine-tuning the parameters to the recent FX-construction proposals, we show that the security margin of these ciphers against practical attacks is smaller than expected. Our techniques combine a special form of time–memory–data trade-offs, typically applied to stream ciphers, with a cryptanalytic technique by Fouque, Joux and Mavromati. In the final part of the paper, we show that the techniques we use in cryptanalysis of the FX-construction are applicable to additional schemes. In particular, we use related methods in order to devise new time–memory trade-offs for solving the affine equivalence problem. In this problem, the input consists of two functions $$F,G: \{0,1\}^n \rightarrow \{0,1\}^n$$ , and the goal is to determine whether there exist invertible affine transformations $$A_1,A_2$$ over $$GF(2)^n$$ such that $$G = A_2 \circ F \circ A_1$$ .

Age differences in the relationship between cortisol and emotional memory.

Research has shown that remembering emotional information can occur at the expense of surrounding neutral background information; this emotional memory trade-off occurs similarly in both younger and older adults. We investigated how levels of cortisol, a hormone that acts on the central nervous system, impact emotional memory with age. Younger and older adult participants incidentally encoded emotional (positive, negative, or neutral) items placed on neutral backgrounds and later completed recognition tests for both the items and the backgrounds. Cortisol was measured at multiple time points to assess basal cortisol. Results are reported for prelearning levels, as findings were comparable across time points. Results revealed that higher levels of cortisol predicted a lower memory trade-off effect for older adults compared to younger adults and that this age difference in the role of cortisol tended to be strongest for memory for negative items (rather than for backgrounds or neutral items). No such interaction emerged for the positive trade-off effect. These results suggest that cortisol levels play a different role in supporting emotional memory across the life span, with lower levels of cortisol potentially more adaptive for memory for negative emotional information and higher levels indicating potential impairment with age. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Coded Caching for Heterogeneous Systems: An Optimization Perspective

In cache-aided networks, the server populates the cache memories at the users during low-traffic periods in order to reduce the delivery load during peak-traffic hours. In turn, there exists a fundamental tradeoff between the delivery load on the server and the cache sizes at the users. In this paper, we study this tradeoff in a multicast network, where the server is connected to users with unequal cache sizes and the number of users is less than or equal to the number of library files. We propose centralized uncoded placement and linear delivery schemes which are optimized by solving a linear program. Additionally, we derive a lower bound on the delivery memory tradeoff with uncoded placement that accounts for the heterogeneity in cache sizes. We explicitly characterize this tradeoff for the case of three end-users, as well as an arbitrary number of end-users when the total memory size at the users is small, and when it is large. Next, we consider a system where the server is connected to the users via rate-limited links of different capacities and the server assigns the users’ cache sizes subject to a total cache budget. We characterize the optimal cache sizes that minimize the delivery completion time with uncoded placement and linear delivery. In particular, the optimal memory allocation balances between assigning larger cache sizes to users with low capacity links and uniform memory allocation.

Breaking High-Resolution CNN Bandwidth Barriers With Enhanced Depth-First Execution

Convolutional neural networks (CNNs) now also start to reach impressive performance on non-classification image processing tasks, such as denoising, demosaicing, super-resolution, and super slow motion. Consequently, CNNs are increasingly deployed on very high-resolution images. However, the resulting high-resolution feature maps pose unseen requirements on the memory system of neural network processing systems, as on-chip memories are too small to store high-resolution feature maps, while off-chip memories are very costly in terms of I/O bandwidth and power. This paper first shows that the classical layer-by-layer inference approaches are bounded in their external I/O bandwidth versus on-chip memory tradeoff space, making it infeasible to scale up to very high resolutions at a reasonable cost. Next, we demonstrate how an alternative depth-first network computation can reduce I/O bandwidth requirements up to ${>}200\times $ for a fixed on-chip memory size or, alternatively, reduce on-chip memory requirements up to ${>}10\,000\times $ for a fixed I/O bandwidth limitation. We further introduce an enhanced depth-first method, exploiting both line buffers and tiling, to further improve the external I/O bandwidth versus on-chip memory capacity tradeoff and quantify its improvements beyond the current state of the art.

Acute sleep deprivation and the selective consolidation of emotional memories.

Research suggests that sleep preferentially consolidates the negative aspects of memories at the expense of the neutral aspects. However, the mechanisms by which sleep facilitates this emotional memory trade-off remain unknown. Although active processes associated with sleep-dependent memory consolidation have been proposed to underlie this effect, this trade-off may also be modulated by non-sleep-related processes, such as the circadian factors, stress-related factors, and/or mood congruent context effects involved in sleep deprivation. We sought to examine the potential role of these factors by randomizing 39 young adults into either a total sleep deprivation condition (26 consecutive hours awake) or a sleep condition (8 h sleep opportunity). Replicating the emotional memory trade-off effect, negative objects were better remembered than neutral objects or background images. However, in spite of generally worse memory performance (for neutral and background information), sleep-deprived participants showed similar recognition rates for negative emotional memories relative to participants who were given a full night of sleep.

Memory facilitation for emotional faces: Visual working memory trade-offs resulting from attentional preference for emotional facial expressions.

Visual working memory (VWM) for faces is facilitated when they display negative facial expressions. The present study manipulated the emotional heterogeneity of the encoding display in a change detection task to examine whether VWM is enhanced by having a separate memory store or by a bias in the allocation of limited attentional resource. When the encoding display was emotionally heterogeneous, regardless of whether happy or fearful facial expressions were presented, memory for emotional faces increased while memory for neutral faces decreased, indicating a memory trade-off. To investigate whether this occurred as a result of preferential allocation of attentional resource towards emotional expressions over neutral ones, faces were shown sequentially in different quadrants of the display. The memory trade-off between happy and neutral faces disappeared but persisted between fearful and neutral faces at trailing serial positions. When blank intervals were inserted between faces to prevent fearful faces from having prolonged processing that consumes attentional resource that should be shared with neutral faces, the memory trade-off disappeared. Findings support the argument that emotional expressions facilitate VWM due to their bias in obtaining attentional resource but the exact mechanisms through which limited resource is allocated between happy and fearful expressions may differ.

Cryptanalytic time–memory trade-off for password hashing schemes

Increasing threat of password leakage from compromised password hashes demands a resource consuming password-hashing algorithm to prevent the precomputation of the password hashes. A class of password-hashing schemes (PHS) provides such a defense by making the design Memory hard. This ensures that any reduction in the memory consumed by the algorithm leads to an exponential increase in its runtime. The security offered by a memory-hard PHS design is measured in terms of its time–memory trade-off (TMTO) defense. Another important measure for a good PHS is its efficiency in utilizing all the available memory as quickly as possible, and fast running time when more than the required memory is available. In this work, we present a simple technique to analyze TMTO for a password-hashing scheme which can be represented as a directed acyclic graph (DAG). The nodes of the DAG correspond to the storage required by the algorithm and the edges correspond to the flow of the execution. Our proposed technique provides expected runtimes at varied levels of available storage utilizing the DAG representation of the algorithm. We show the effectiveness of our proposed technique by applying it on three designs from the “Password Hashing Competition" (PHC)—Argon2-Version 1.2.1 (the PHC winner), Catena-Version 3.2 and Rig-Version 2. Our analysis shows that Argon2i is not providing expected memory hardness which is also highlighted in a recent work by Corrigan-Gibbs et al. We analyze these PHS for performance under various settings of time and memory complexities. Our experimental results show (i) simple DAGs for PHS are efficient but not memory hard, (ii) complex DAGs for PHS are memory hard but less efficient, and (iii) combination of two simple graphs in the representation of a DAG for PHS achieves both memory hardness and efficiency.

Preferential consolidation of emotionally salient information during a nap is preserved in middle age.

Sleep preferentially preserves aspects of memory that are most salient and valuable to remember at the expense of memory for less relevant details. Daytime naps and nocturnal sleep enhance this emotional memory trade-off effect, with memory for emotional components correlated with slow-wave sleep during the day and rapid eye movement sleep overnight. However, these studies have primarily sampled from young adult populations. Sleep and memory are altered by middle age, and the aim of the present study was to examine how age affects sleep-based mechanisms of emotional memory prioritization, using a daytime nap protocol to compare young to middle-aged adults. In both age groups, a nap soon after encoding scenes that contained a negative or neutral object on a neutral background led to superior retention of emotional object memory at the expense of memory for the related backgrounds. Sleep spindle activity during slow-wave sleep was related to memory for this emotionally salient information across the age range.

Experimenting with runtime and energy tradeoffs in high-performance computing

In a given organisation or society, energy dependence increases rapidly due to shipping, transportation, and even food production. This dependency generally results in high costs and pollution, which threatens to disrupt our ecosystem. At this time, the earth is rapidly approaching a point of no return that requires international cooperation. In the following decade, reliance on effective energy-computing designs will become imperative, as power and cooling begin to cause restrictions on microchip clock speeds. Therefore, personal computer organisations are fast expanding on-chip parallelism to expedite execution. Combined operations are the most fundamental part of a transmission in shared and distributed parallel applications. In this paper, the tradeoffs between energy, memory, and runtime of various algorithms that accomplish such operations are investigated. The influence of aggregate transmissions on the execution of parallel calculation, specifically, is shown. A nondirect association with execution seen in the energy required is also presented. The best streamlining between runtime, energy, and memory tradeoff is demonstrated and a better result in the energy-effective execution of calculations is displayed.

Experimenting with runtime and energy tradeoffs in high-performance computing

In a given organisation or society, energy dependence increases rapidly due to shipping, transportation, and even food production. This dependency generally results in high costs and pollution, which threatens to disrupt our ecosystem. At this time, the earth is rapidly approaching a point of no return that requires international cooperation. In the following decade, reliance on effective energy-computing designs will become imperative, as power and cooling begin to cause restrictions on microchip clock speeds. Therefore, personal computer organisations are fast expanding on-chip parallelism to expedite execution. Combined operations are the most fundamental part of a transmission in shared and distributed parallel applications. In this paper, the tradeoffs between energy, memory, and runtime of various algorithms that accomplish such operations are investigated. The influence of aggregate transmissions on the execution of parallel calculation, specifically, is shown. A nondirect association with execution seen in the energy required is also presented. The best streamlining between runtime, energy, and memory tradeoff is demonstrated and a better result in the energy-effective execution of calculations is displayed.

Very Efficient Tone Reservation PAPR Reduction Fully Compatible With ATSC 3.0 Standard: Performance and Practical Implementation Analysis

A common issue in any multicarrier communication system such as the American digital video broadcasting (ATSC 3.0) standard is the high peaks of the transmitted signal. This disadvantage constrains the high power amplifiers to be deployed in their linear region which lowers their power efficiency. To overcome this issue, various techniques aiming at reducing the signal fluctuations have been investigated. Recently, Tone Reservation (TR)-based algorithms have been studied and proposed for the second generation of digital video broadcasting (DVB-T2) and ATSC 3.0 standards. The algorithm is essentially based on an iterative gradient approach to cancel one peak of the time-domain signal at each iteration. In this paper, we propose a novel TR-based algorithm implementable and compatible with the ATSC 3.0 standard and named as grouped carrier peak windowing (GCPW). This algorithm is based on a new kernel definition targeting the cancellation of multiple signal peaks at a time which highly reduces the total number of iterations, therefore reducing the system global latency and being more suited for implementation in today’s ATSC 3.0 transmitters. Taking into account hardware resources requirements, we propose a new method to select the highest signal peaks to be considered in the PAPR reduction process. Hence, the system latency, complexity, and memory resources are reduced and better performance than the ATSC 3.0 gradient-based algorithm can be offered. The implementation of the GCPW algorithm in fixed-point architectures is also studied and optimized in this paper. We demonstrate through simulation results that the proposed algorithm offers very good performance/latency/complexity/memory tradeoff in both floating and fixed point implementations.

Mobile Phone Security Based New Strong Genetic Stream Cipher Design

Mobile phones are considered to be the most common communication devices in history. Recently, mobile phones are not only used for communication but also to send and receive important data such as social security numbers, bank account details and passwords. Mobile phone communication uses the encryption algorithms collectively called as A5 family which corresponds to symmetric-key Stream ciphers that generate pseudo-random binary sequences used to encrypt the message signals on bit-by-bit basis. Unfortunately all these algorithms that ensure the security of mobile communications are cryptanalyzed and suffer from several attacks. In this paper, a new genetic pseudo random bit generator (PRBG) based on genetic algorithm is proposed to make mobile phone encryption algorithm A5 robust and resistive to the attacks such as time memory trade off, divide and conquer. A basic security analysis shows that the proposed algorithm is more resistant for cryptanalysis with a good quality of bits stream produced by our generator called genetic A5.

Older adults encode more, not less: evidence for age-related attentional broadening

ABSTRACTPrevious work has shown that older adults attend to and implicitly remember more distracting information than young adults; however, it is unknown whether they show a corresponding decrease in implicit memory for targets in the presence of distracters. Using implicit memory tests, we asked whether older adults show a tradeoff in memory between targets and distracters. Here, young and older adults performed a selective attention task in which they were instructed to attend to target pictures and ignore superimposed distracter words. We measured priming for distracter words using fragment completion and for target pictures using naming time. Older adults showed greater priming for distracting words compared to young adults, but equivalent priming for target pictures. These results suggest that older adults have a broader attentional scope than young adults, encompassing both relevant and irrelevant information.

Arousal amplifies biased competition between high and low priority memories more in women than in men: The role of elevated noradrenergic activity

Recent findings indicate that emotional arousal can enhance memory consolidation of goal-relevant stimuli while impairing it for irrelevant stimuli. According to one recent model, these goal-dependent memory tradeoffs are driven by arousal-induced release of norepinephrine (NE), which amplifies neural gain in target sensory and memory processing brain regions. Past work also shows that ovarian hormones modulate activity in the same regions thought to support NE’s effects on memory, such as the amygdala, suggesting that men and women may be differentially susceptible to arousal’s dual effects on episodic memory. Here, we aimed to determine the neurohormonal mechanisms that mediate arousal-biased competition processes in memory. In a competitive visuo-attention task, participants viewed images of a transparent object overlaid on a background scene and explicitly memorized one of these stimuli while ignoring the other. Participants then heard emotional or neutral audio-clips and provided a subjective arousal rating. Hierarchical generalized linear modeling (HGLM) analyses revealed that greater pre-to-post task increases in salivary alpha-amylase (sAA), a biomarker of noradrenergic activity, was associated with significantly greater arousal-enhanced memory tradeoffs in women than in men. These sex-dependent effects appeared to result from phasic and background noradrenergic activity interacting to suppress task-irrelevant representations in women but enhancing them in men. Additionally, in naturally cycling women, low ovarian hormone levels interacted with increased noradrenergic activity to amplify memory selectivity independently of emotion-induced arousal. Together these findings suggest that increased noradrenergic transmission enhances preferential consolidation of goal-relevant memory traces according to phasic arousal and ovarian hormone levels in women.

A Proposed Lower Computational Complexity Secret Key Mirroring System on GSM

Global system for mobile communication is a wireless radio technology used mostly on network communication. It is designed to overcome the challenges of analog communication. GSM evolved from generation 1G to 4G LTE and uses protocols to protect transmissions, which have shown to be susceptible to attacks. This fact has been proven based on several attacks ranging from narrow pipe attack, guess, and determine attacks, side channel attacks, time memory tradeoff attacks and correlation attacks which have high computational complexities. The proposed system called GSM Traffic Monitoring System (GTMS) attempts to proffer a lower computational complexity attack. It uses a key retrieval and passive attack module to handle the mirroring of the secret key authentication procedure given a chosen random challenge on a SIM card through the injection of a malware. This research aims at drawing the attention of network providers- SIM configuration; an area that requires protection from attackers.

Automatic Search of Threshold Implementations of 4‐Bit S‐Boxes Resisting DPA

The threshold implementation method of Substitution box (S-box) has been proposed by Nikova et al. for resisting first-order Differential power attacks with glitches. To lower the time complexity for a threshold implementation of a specific non-linear function, one needs to decompose the function first and then search possible share methods for it. However, the time complexity for this search process is still non-trivial. In this paper, an effective method of searching threshold implementations of 4-bit S-boxes is proposed. It mainly consists of two stages. For the decomposing stage, an efficient way of decomposing an S-box is introduced. For the sharing stage, the search complexity is lowered by the technique of time memory trade-off. As a result, threshold implementations of various lightweight block ciphers’ S-boxes are given. Moreover, our method is applied to each 4-bit involutive S-box and some candidates of threshold implementations are presented.