Similar Latency Research Articles

Self-adaptive smoothing model for cardinality estimation

Abstract Cardinality estimation is a crucial component in query optimizers. After decades of research, employing autoregressive models for cardinality estimation has demonstrated remarkable accuracy. However, when queries involve attributes with large domain sizes, autoregressive model-based estimators struggle to accurately capture the data distribution, leading to poor performance. Furthermore, these models often exhibit significant errors when handling queries with low-selectivity predicates. To address these challenges, we propose a self-adaptive cardinality estimator named AdaCard. Initially, we employ a self-adaptive smoothing factor selection strategy to variably adjust the original data, thereby mitigating the impact of large domain sizes. Secondly, to correct errors stemming from Monte Carlo sampling, we utilize resampling to refine the handling of low-selectivity predicates, thereby improving accuracy. Through evaluation using four real-world benchmarks, we compared AdaCard with mainstream baselines. The final results show that our estimator has the lowest tail estimation error and improves accuracy by nearly 10$\times $ over the second-best method, with similar latency and model size.

A Quadruple Gene-Deleted Live BoHV-1 Subunit RVFV Vaccine Vector Reactivates from Latency and Replicates in the TG Neurons of Calves but Is Not Transported to and Shed from Nasal Mucosa.

Bovine herpesvirus type 1 (BoHV-1) establishes lifelong latency in trigeminal ganglionic (TG) neurons following intranasal and ocular infection in cattle. Periodically, the latent virus reactivates in the TG due to stress and is transported anterogradely to nerve endings in the nasal epithelium, where the virus replicates and sheds. Consequently, BoHV-1 is transmitted to susceptible animals and maintained in the cattle population. Modified live BoHV-1 vaccine strains (BoHV-1 MLV) also have a similar latency reactivation. Therefore, they circulate and are maintained in cattle herds. Additionally, they can regain virulence and cause vaccine outbreaks because they mutate and recombine with other circulating field wild-type (wt) strains. Recently, we constructed a BoHV-1 quadruple mutant virus (BoHV-1qmv) that lacks immune evasive properties due to UL49.5 and glycoprotein G (gG) deletions. In addition, it also lacks the gE cytoplasmic tail (gE CT) and Us9 gene sequences designed to make it safe, increase its vaccine efficacy against BoHV-1, and restrict its anterograde neuronal transport noted above. Further, we engineered the BoHV-1qmv-vector to serve as a subunit vaccine against the Rift Valley fever virus (BoHV-1qmv Sub-RVFV) (doi: 10.3390/v15112183). In this study, we determined the latency reactivation and nasal virus shedding properties of BoHV-1qmv (vector) and BoHV-1qmv-vectored subunit RVFV (BoHV-1qmv sub-RVFV) vaccine virus in calves in comparison to the BoHV-1 wild-type (wt) following intranasal inoculation. The real-time PCR results showed that BoHV-1 wt- but not the BoHV-1qmv vector- and BoHV-1qmv Sub-RVFV-inoculated calves shed virus in the nose following dexamethasone-induced latency reactivation; however, like the BoHV-1 wt, both the BoHV-1qmv vector and BoHV-1qmv Sub-RVFV viruses established latency, were reactivated, and replicated in the TG neurons. These results are consistent with the anterograde neurotransport function of the gE CT and Us9 sequences, which are deleted in the BoHV-1qmv and BoHV-1qmv Sub-RVFV.

Primate superior colliculus is causally engaged in abstract higher-order cognition.

The superior colliculus is an evolutionarily conserved midbrain region that is thought to mediate spatial orienting, including saccadic eye movements and covert spatial attention. Here, we reveal a role for the superior colliculus in higher-order cognition, independent of its role in spatial orienting. We trained rhesus macaques to perform an abstract visual categorization task that involved neither instructed eye movements nor differences in covert attention. We compared neural activity in the superior colliculus and the posterior parietal cortex, a region previously shown to causally contribute to abstract category decisions. The superior colliculus exhibits robust encoding of learned visual categories, which is stronger than in the posterior parietal cortex and arises at a similar latency in the two areas. Moreover, inactivation of the superior colliculus markedly impaired animals' category decisions. These results demonstrate that the primate superior colliculus mediates abstract, higher-order cognitive processes that have traditionally been attributed to the neocortex.

Performance evaluation of containers for low-latency packet processing in virtualized network environments

Packet processing in current network scenarios faces complex challenges due to the increasing prevalence of requirements such as low latency, high reliability, and resource sharing. Virtualization is a potential solution to mitigate these challenges by enabling resource sharing and on-demand provisioning; however, ensuring high reliability and ultra-low latency remains a key challenge. Since bare-metal systems are often impractical because of high cost and space usage, and the overhead of virtual machines (VMs) is substantial, we evaluate the utilization of containers as a potential lightweight solution for low-latency packet processing. Herein, we discuss the benefits and drawbacks and encourage container environments in low-latency packet processing when the degree of isolation of customer data is adequate and bare metal systems are unaffordable. Our results demonstrate that containers exhibit similar latency performance with more predictable tail-latency behavior than bare metal packet processing. Moreover, deciding which mainboard architecture to use, especially the cache division, is equally vital as containers are prone to higher latencies on more shared caches between cores especially when other optimizations cannot be used. We show that this has a higher impact on latencies within containers than on bare metal or VMs, resulting in the selection of hardware architectures following optimizations as a critical challenge. Furthermore, the results reveal that the virtualization overhead does not impact tail latencies.

Study of Visual Evoked Potentials in Schoolchildren: A Promising Aid to Pediatric Ophthalmology.

Background Visual evoked potential (VEP) is a noninvasive investigation conducted to identify abnormalities in the visual system. It is especially suitable for young children who are unable to express visual symptoms or participate in conventional vision tests. This study was undertaken to examine the VEP among schoolchildren to assess the functionality of their optic pathway. Methodology This short-term observational study was performed in the Clinical Neurophysiology Unit of the Physiology Department of a rural medical college. The study population consisted of 60 schoolchildren aged 7-12. Both eyes were examined for transient pattern reversal VEP recordingsusing a Recorders & Medicare Systems Electromyography-Evoked Potential recorder (RMS EMG-EP MARK-II Pvt. Ltd., Chandigarh, India). Results VEPs were analyzed for latency and amplitude of the main components, namely P100, N70, and N155. The results showedmarkedly extended P100 latency in33.33%, i.e., eight outof 24 eyes of standard (std.) III children. Similar latency prolongation was obtained in 36.36% (eight out of 22)eyes of std. IV, 30% (six of 20 eyes) of std. V, 13.63% (three of 22 eyes) of std. VI, and 50% (eight of 16 eyes) in std. VII and VIIIchildren. A markedly reduced P100 amplitude was observedin two of 20 eyes (10%) of std. V, two of 16 eyes (12.5%) in std. VII and VIIIchildren, amounting to a P100amplitude abnormality in5%eyesin toto. The interocular differences in all VEP parameters amongthe subjects were statistically insignificant. Conclusion In schoolchildren in whom normal latencies and amplitudes were obtained, the presence of reproducible VEPs indicated the normal functionalstatus of their visual pathway. On the other hand,in those children where alteredVEP findings were found, it hinted towardcomplementary informationthat they may have underlying ocular disordersthat were yet to be diagnosed. Hence, this study provides insight into the assessment of visual system function, which is primarily difficult in young children.

Chimpanzee gestural exchanges share temporal structure with human language

Humans regularly engage in efficient communicative conversations, which serve to socially align individuals1. In conversations, we take fast-paced turns using a human-universal structure of deploying and receiving signals which shows consistent timing across cultures2. We report here that chimpanzees also engage in rapid signal-to-signal turn-taking during face-to-face gestural exchanges with a similar average latency between turns to that of human conversation. This correspondence between human and chimpanzee face-to-face communication points to shared underlying rules in communication. These structures could be derived from shared ancestral mechanisms or convergent strategies that enhance coordinated interactions or manage competition for communicative 'space'.

Electric Auditory Brainstem Response Audiometry in Cochlear Implants: New Recording Paradigm.

(1) Background: Cochlear implants (CIs) are widely applied to recover audition for patients with severe degrees of or total hearing loss. Electrical stimulation using the electrically evoked ABR (E-ABR) can be recorded in CI recipients through the device. This work was designed to study E-ABR recorded individually from different channels located at the apical, middle, and basal cochlear regions in comparison to their simultaneous separated or adjacent combined recordings. (2) Methods: This study included 17 children fitted with unilateral cochlear implants. All children were subjected to impedance measurement, electrical compound action potentials (ECAP), and E-ABR recording of three channels located at the apical, middle, and basal cochlear regions. This was followed by simultaneous E-ABR recording of the three "separated" channels in comparison to E-ABR recording from three adjacent channels located at the middle cochlear region. (3) Results: Similar E-ABR latencies and amplitudes were found using either individual or simultaneously separated or adjacent combined recording. However, the mean amplitude measures of E-ABR for combined adjacent channels showed a positive correlation with the applied current level. (4) Conclusions: Combined E-ABR recording from adjacent channels is a faster and more reliable technique that can be used effectively without compromising the results of the recorded E-ABR.

Concurrent service auto-scaling for Knative resource quota-based serverless system

Serverless computing platforms currently provide application developers with two ways to control their services’ resource usage cost: resource usage-based and resource quota-based. In usage-based systems, resources are assigned to services based on the amount they consume. Meanwhile, a fixed resource amount is reserved and shared between services for quota-based systems. Several studies have been proposed to enhancing the default serverless auto- scaling algorithms to optimize resource usage and service quality. However, almost all previous works targeted usage-based systems and optimized auto-scaling performance for each separate service. In contrast, this work targets auto-scaling of concurrent services in serverless quota-based systems. In serverless quota-based systems, over-quota resource usage and latency Service Level Objective (SLO) violation may occur when auto-scaling new instances during burst traffic moments. Hence, we aim to find an optimal hybrid auto-scaling decision to minimize over-quota resource usage and latency SLO violation. To solve this problem, We applied deep reinforcement learning and traffic prediction techniques. Our solution is developed and implemented based on the characteristics of the most popular open-source serverless platform Knative. For evaluation, we compared our solution with the default Knative auto-scaler and our previously proposed usage-based hybrid Knative auto-scaler. We configured the default Knative auto-scaler with two different settings that can optimize the total resource usage of all services or minimize service latency. Compared to the optimized resource usage version, our solution traded a slightly higher resource usage for an 11.3% latency SLO violation duration reduction. Meanwhile, compared with the optimized latency version, our solution reduced the over-quota resource usage rate by 18.25% while achieving a similar latency SLO preservation performance. Compared to the usage-based hybrid auto-scaler, the latency SLO violation rate and over-quota resource usage were approximately reduced by half.

SCIPIS: Scalable and concurrent persistent indexing and search in high-end computing systems

While it is now routine to search for data on a personal computer or discover data online, there is no such equivalent method for discovering data on large parallel and distributed file systems commonly deployed on HPC systems. In contrast to web search, which has to deal with a larger number of relatively small files, in HPC applications there is a need to also support efficient indexing of large files. We propose SCIPIS, an indexing and search framework, that can exploit the properties of modern high-end computing systems, with many-core architectures, multiple NUMA nodes and multiple NVMe storage devices. SCIPIS supports building and searching TFIDF persistent indexes, and can deliver orders of magnitude better performance than state-of-the-art approaches. We achieve scalability and performance of indexing by decomposing the indexing process into separate components that can be optimized independently, by building disk-friendly data structures in-memory that can be persisted in long sequential writes, and by avoiding communication between indexing threads that collaboratively build an index over a collection of large files. We evaluated SCIPIS with three types of datasets (logs, scientific data, and metadata), on systems with configurations up to 192-cores, 768 GiB of RAM, 8 NUMA nodes, and up to 16 NVMe drives, and achieved up to 29x better indexing while maintaining similar search latency when compared to Apache Lucene.

Exploring the impact of tonal inventory on speech perception across languages: a study of MMN responses in tonal language speakers.

Previous research on the perception of segmental features of languages has established a correlation between the phoneme inventory of a language and its speakers' perceptual abilities, as indexed by discrimination tasks and Mismatch Negativity (MMN). Building on this background, the current study elucidated the relationship between perceptual ability and tonal inventory by utilizing two tonal languages. Two groups of participants were included in the present experiment: Mandarin speakers and Hakka-Mandarin speakers. Onset latency analysis revealed a significant difference in the Mandarin syllable condition, with Hakka-Mandarin speakers demonstrating earlier MMN latency than Mandarin speakers. This suggests a more efficient auditory processing mechanism in Hakka-Mandarin speakers. Both groups, however, showed similar MMN latency in the Hakka syllable condition. The interaction between language background and syllable type indicates that other factors, such as syllable sonority, also influence MMN responses. These findings highlight the importance of considering multiple phonemic inventories and syllable characteristics in studies of tonal perception.

Relationship between schematic and dynamic expectations of melodic patterns in music perception

Prediction is fundamental in music listening. Two types of expectations have been proposed: schematic expectations, which arise from knowledge of tonal regularities (e.g., harmony and key) acquired through long-term plasticity and learning, and dynamic expectations, which arise from short-term regularity representations (e.g., rhythmic patterns and melodic contours) extracted from ongoing musical contexts. Although both expectations are indispensable in music listening, how they interact with each other in music prediction remains unclear. The present study examined the relationship between schematic and dynamic expectations in music processing using event-related potentials (ERPs). At the ending note of the melodies, the schematic expectation was violated by presenting a note with music-syntactic irregular (i.e., outof- key note), while the dynamic expectation was violated by presenting a contour deviant based on online statistical learning of melodic patterns. Schematic and dynamic expectations were manipulated to predict the same note. ERPs were recorded for the music-syntactic irregularity and the contour deviant, which occurred independently or simultaneously. The results showed that the music-syntactic irregularity elicited an early right anterior negativity (ERAN), reflecting the prediction error in the schematic expectation, while the contour deviant elicited a mismatch negativity (MMN), reflecting the prediction error in the dynamic expectation. Both components occurred within a similar latency range. Moreover, the ERP amplitude was multiplicatively increased when the irregularity and deviance occurred simultaneously. These findings suggest that schematic and dynamic expectations function concurrently in an interactive manner when both expectations predict the same note.

Clinical and Molecular Characterization of Patients with Therapy Related Myeloid Neoplasms (TRMN)

Acknowledgements Chemotherapy and/or radiotherapy in cancer patients compose a future risk of developing a therapy related myeloid neoplasm (TRMN). However, the presence of a germline landscape might contribute and modify the overall risk. It has been suggested that around 18.5% of TRMN patients have a germline cancer mutation. In particular, cancer predisposing genes or syndromes involving alterations in the DNA repair mechanism such as CHEK2, BRCA1, BRCA2, MLH1, MSH2, MSH6 or PMS2 might be enriched in patients who develop a primary tumor (PT) and a subsequent secondary myeloid neoplasm. The role of the alterations in cancer susceptibility genes in association with the treatment for the PT in the development of TRMN is still unclear. To evaluate the clinical and genetic landscape of TRMN patients to understand the role of different risk factors and provide tools for differential diagnosis and clinical management. Clinical evaluation of 96 patients with TRMN and 12 patients with a secondary myeloid neoplasm after a non-treated with chemotherapy primary tumor (nTMN) was performed. In addition, germline landscape and somatic alterations were studied in the TRMN series by tNGS (N=49) and WES (N=47). Tumoral sample was obtained from bone marrow. CD3+ T lymphocytes from peripheral blood (PB) were enriched by immunomagnetic selection and used as germline/control sample. A minimum of 98% purity in CD3+ was selected to prevent myeloid contamination. Variant frequency (VAF) <30% found in tumor but not in CD3+ sample was annotated as somatic alteration. Only pathogenic/likely pathogenic variants were considered. The median age of onset was 62.3 and 71.1 years for the PT and the TRMN, respectively. 32.5% had complex karyotype. Similar positive correlation was found between the age of onset of the PT and the age of onset of the TRMN and nTNM. A negative correlation was found between the age of onset of the PT and the latency until the TRMN and nTMN diagnosis, which suggests that elderly age condition is more relevant than the cytotoxic treatment (Fig.1). No differences in latencies were found between MN subtypes, despite ring sideroblasts and del(5q) myeloid subtypes correlated with shorter and higher latencies, respectively. Different latencies were neither found when the PT was solid or hematologic, but interestingly, TRMN patients with previous colorectal cancer had shorter latencies. On the other hand, 91.3% of the TRMN patients presented a molecular alteration (considering both genetic or cytogenetic alterations), including 60.9% and 75% of patients with germline and acquired alterations, respectively. Germline mutations included 52.2% and 47.8% annotated in cancer predisposition genes of the DNA repair mechanisms and myeloid genes, respectively. Only 39.1% of TRMN patients were found with pathogenic somatic variants in myeloid genes while 68.75% were found with an abnormal karyotype. Finally, higher number of germline and somatic mutations was found in TRMN patients with an abnormal karyotype. However, a higher percentage of germline mutations in myeloid genes was found in TRMN with a normal karyotype (Fig.2). Higher percentage of molecular alterations (both germline and somatic) in myeloid genes was found in TRMN patients with a previous solid PT. However, higher percentage of mutations in cancer predisposition genes was found when the PT was hematologic. Our results highlight the role of mutations in cancer predisposition genes in the development of TRMN. Similar latency associations were found for TRMN and nTMN patients, which suggest that other risk factors different than treatment might contribute to the TRMN development. Altered karyotypes in TRMN patients are associated with acquired mutations in myeloid genes but not with germline mutations, which suggests two different entities with different prognosis. Molecular alterations in myeloid genes are more relevant in TRMN patients with solid PT, while molecular alterations in cancer predisposition genes are associated with TRMN patients with hematologic PT. This work was supported in part by a grant from the Instituto de Salud Carlos III, Ministerio de Economia y Competitividad, Spain (PI 20/00531)(Co-funded by European Regional Development Fund. ERDF, a way to build Europe). 2021 SGR 00560 (GRC) Generalitat de Catalunya; economical support from CERCA Programme and Fundació Adey.

The QARMAv2 Family of Tweakable Block Ciphers

We introduce the QARMAv2 family of tweakable block ciphers. It is a redesign of QARMA (from FSE 2017) to improve its security bounds and allow for longer tweaks, while keeping similar latency and area. The wider tweak input caters to both specific use cases and the design of modes of operation with higher security bounds. This is achieved through new key and tweak schedules, revised S-Box and linear layer choices, and a more comprehensive security analysis. QARMAv2 offers competitive latency and area in fully unrolled hardware implementations.Some of our results may be of independent interest. These include: new MILP models of certain classes of diffusion matrices; the comparative analysis of a full reflection cipher against an iterative half-cipher; our boomerang attack framework; and an improved approach to doubling the width of a block cipher.

A motor plan is accessible for voluntary initiation and involuntary triggering at similar short latencies.

Movement goals are an essential component of motor planning, altering voluntary and involuntary motor actions. While there have been many studies of motor planning, it is unclear if motor goals influence voluntary and involuntary movements at similar latencies. The objectives of this study were to determine how long it takes to prepare a motor action and to compare this time for voluntary and involuntary movements. We hypothesized a prepared motor action would influence voluntarily and involuntarily initiated movements at the same latency. We trained subjects to reach with a forced reaction time paradigm and used a startling acoustic stimulus (SAS) to trigger involuntary initiation of the same reaches. The time available to prepare was controlled by varying when one of four reach targets was presented. Reach direction was used to evaluate accuracy. We quantified the time between target presentation and the cue or trigger for movement initiation. We found that reaches were accurately initiated when the target was presented 48ms before the SAS and 162ms before the cue to voluntarily initiate movement. While the SAS precisely controlled the latency of movement onset, voluntary reach onset was more variable. We, therefore, quantified the time between target presentation and movement onset and found no significant difference in the time required to plan reaches initiated voluntarily or involuntarily (∆ = 8ms, p = 0.2). These results demonstrate that the time required to plan accurate reaches is similar regardless of if they are initiated voluntarily or triggered involuntarily. This finding may inform the understanding of neural pathways governing storage and access of motor plans.

Trends in referral patterns to presurgical evaluation at a European reference center

PurposeTo determine if growing evidence for epilepsy surgery as an early treatment option is reflected in the decrease of latencies between epilepsy onset and referral for presurgical evaluation MethodsRetrospective analysis of latencies in 1646 patients (children and adults) from the time of epilepsy diagnosis to first presurgical workup in the period from 1999 to 2019 based on electronic patient charts at a tertiary epilepsy center. Time spans 1999–2009 and 2010–2019, prior to and following the ILAE definition of pharmacoresistance, and the role of etiological factors were assessed. ResultsOver the whole period, the mean latency between diagnosis and a presurgical workup was 15.3 y. There was a significant reduction in the latencies between the periods 1999–2009 (16.9 y) and 2010–2019 (13.4 y), (p < 0.0001). In a linear regression analysis, the latency decreased by 2.6 months/year from 17.4 in 1999 to 13.1 y in 2019 (p < 0.001). Subgroup analyses showed significant decreases in latency to presurgical evaluation in patients with hippocampal sclerosis from 24.4 to 19.5 y, in malformations of cortical development from 16.4 to 13.2 y, and in nonlesional patients from 18.1 to 12.8 y, in contrast to patients with MR evidence for brain tumors with similar latencies across time (10.5 vs. 9.5 y, n.s.). ConclusionThe reduction of the time span to a first presurgical evaluation was highly significant over time, yet moderate in its degree. Overall, the aim of early diagnostic evaluation for epilepsy surgery options after established pharmacoresistance was only achieved for a minority of patients.

Single opsin driven white noise ERGs in mice.

Electroretinograms elicited by photopigment isolating white noise stimuli (wnERGs) in mice were measured. The dependency of rod- and cone-opsin-driven wnERGs on mean luminance was studied. Temporal white noise stimuli (containing all frequencies up to 20 Hz, equal amplitudes, random phases) that modulated either rhodopsin, S-opsin or L*-opsin, using the double silent substitution technique, were used to record wnERGs in mice expressing a human L*-opsin instead of the native murine M-opsin. Responses were recorded at 4 mean luminances (MLs).Impulse response functions (IRFs) were obtained by cross-correlating the wnERG recordings with the corresponding modulation of the photopigment excitation elicited by the stimulus. So-called modulation transfer functions (MTFs) were obtained by performing a Fourier transform on the IRFs.Potentials of two repeated wnERG recordings at corresponding time points were plotted against each other. The correlation coefficient (r2repr) of the linear regression through these data was used to quantify reproducibility. Another correlation coefficient (r2ML) was used to quantify the correlations of the wnERGs obtained at different MLs with those at the highest (for cone isolating stimuli) or lowest (for rod isolating stimuli) ML. IRFs showed an initial negative (a-wave like) trough N1 and a subsequent positive (b-wave like) peak P1. No oscillatory potential-like components were observed. At 0.4 and 1.0 log cd/m2 ML robust L*- and S-opsin-driven IRFs were obtained that displayed similar latencies and dependencies on ML. L*-opsin-driven IRFs were 2.5-3 times larger than S-opsin-driven IRFs. Rhodopsin-driven IRFs were observed at -0.8 and - 0.2 log cd/m2 and decreased in amplitude with increasing ML. They displayed an additional pronounced late negativity (N2), which may be a correlate of retinal ganglion cell activity.R2repr and r2ML values increased for cones with increasing ML whereas they decreased for rods. For rhodopsin-driven MTFs at low MLs and L*-opsin-driven MTFs at high MLs amplitudes decreased with increasing frequency, with much faster decreasing amplitudes for rhodopsin. A delay was calculated from MTF phases showing larger delays for rhodopsin- vs. low delays for L*-opsin-driven responses. Opsin-isolating wnERGs in mice show characteristics of different retinal cell types and their connected pathways.

Maze design: size and number of choices impact fish performance in cognitive assays.

Although studies on fish cognition are increasing, consideration of how methodological details influence the ability to detect and measure performance is lagging. Here, in two separate experiments the authors compared latency to leave the start position, latency to make a decision, levels of participation and success rates (whether fish entered the rewarded chamber as first choice) across different physical designs. Experiments compared fish performance across (a) two sizes of T-mazes, large and standard, and a plus-maze, and (b) open choice arenas with either two or four doors. Fish in T-mazes with longer arms took longer to leave the start chamber and were less likely to participate in a trial than fish in T-mazes with shorter arms. The number of options, or complexity, in a maze significantly impacted success but did not necessarily impact behavioural measures, and did not impact the number of fish that reached a chamber. Fish in the plus-maze had similar latencies to leave the start box and time to reach any chamber as fish in the same-sized T-maze but exhibited lower overall success. Similarly, in an open choice arena, increasing the number of options - doors to potential reward chambers - resulted in lower probability of success. There was an influence of reward position in the choice arena, with rewarded chambers closest to the sides of the arena resulting in lower latencies to enter and higher probability of decision success. Together the results allow the authors to offer practical suggestions towards optimal maze design for studies of fish cognition.

Boldness is not associated with dynamic performance capacity in hermit crabs

Boldness, the way an individual reacts to risk, is a commonly studied personality trait in animals. Consistent among-individual differences in startle response durations (latency to recover from a startling stimulus) are frequently assumed to reflect variation in boldness. An alternative explanation is that these latencies are not directly driven by variation in responses to information on risk, but by underlying differences in dynamic performance capacities. Here we investigate this possibility by analysing relationships between locomotory speed, a measure of whole-body dynamic performance capacity in hermit crabs, and startle response duration, a repeatable latency measure used as an index of boldness. Individuals differed in mean startle response duration, in the consistency of their startle responses, in their reaction norms across repeated observations, and mean startle responses increased with crab mass. However, there were no relationships between startle responses and locomotory speed. This indicates that startle responses do not reflect underlying performance capacities and suggests that they provide insight into differences in how individuals respond to risky situations. Since similar latencies are used as measures of boldness in other animals, we suggest that potential relationships between apparent boldness and performance capacity should be tested.

Objects sharpen visual scene representations: evidence from MEG decoding.

Real-world scenes consist of objects, defined by local information, and scene background, defined by global information. Although objects and scenes are processed in separate pathways in visual cortex, their processing interacts. Specifically, previous studies have shown that scene context makes blurry objects look sharper, an effect that can be observed as a sharpening of object representations in visual cortex from around 300 ms after stimulus onset. Here, we use MEG to show that objects can also sharpen scene representations, with the same temporal profile. Photographs of indoor (closed) and outdoor (open) scenes were blurred such that they were difficult to categorize on their own but easily disambiguated by the inclusion of an object. Classifiers were trained to distinguish MEG response patterns to intact indoor and outdoor scenes, presented in an independent run, and tested on degraded scenes in the main experiment. Results revealed better decoding of scenes with objects than scenes alone and objects alone from 300 ms after stimulus onset. This effect was strongest over left posterior sensors. These findings show that the influence of objects on scene representations occurs at similar latencies as the influence of scenes on object representations, in line with a common predictive processing mechanism.

Latency minimization for multiuser computation offloading in fog-radio access networks

Recently, the Fog-Radio Access Network (F-RAN) has gained considerable attention, because of its flexible architecture that allows rapid response to user requirements. In this paper, computational offloading in F-RAN is considered, where multiple User Equipments (UEs) offload their computational tasks to the F-RAN through fog nodes. Each UE can select one of the fog nodes to offload its task, and each fog node may serve multiple UEs. The tasks is computed by the fog nodes or further offloaded to the cloud via a capacity-limited fronhaul link. In order to compute all UEs' tasks quickly, joint optimization of UE-Fog association, radio and computation resources of F-RAN is proposed to minimize the maximum latency of all UEs. This min-max problem is formulated as a Mixed Integer Nonlinear Program (MINP). To tackle it, first, MINP is reformulated as a continuous optimization problem, and then the Majorization Minimization (MM) method is used to find a solution. The MM approach that we develop is unconventional in that each MM subproblem is solved inexactly with the same provable convergence guarantee as the exact MM, thereby reducing the complexity of MM iteration. In addition, a cooperative offloading model is considered, where the fog nodes compress-and-forward their received signals to the cloud. Under this model, a similar min-max latency optimization problem is formulated and tackled by the inexact MM. Simulation results show that the proposed algorithms outperform some offloading strategies, and that the cooperative offloading can exploit transmission diversity better than noncooperative offloading to achieve better latency performance.