Redundant Target Research Articles

Scheduling for single agile satellite, redundant targets problem using complex networks theory

Scheduling for the Earth observation satellites (EOSs) imaging mission is a complicated combinatorial optimization problem, especially for the agile EOSs (AEOSs). The increasing observation requirements and orbiting satellites have exacerbated the scheduling complexity in recent years. In this paper, the single agile satellite, redundant observation targets scheduling problem is studied. We introduce the theory of complex networks and find similarities between AEOS redundant targets scheduling problem and the node centrality ranking problem. Then we model this problem as a complex network, regarding each node as a possible observation opportunity, and define two factors, node importance factor and target importance factor, to describe the node/target importance. Based on the two factors, we propose a fast approximate scheduling algorithm (FASA) to obtain the effective scheduling results. Simulation results indicate the FASA is quite efficient and with broad suitability. Our work is helpful in the EOSs and AEOSs scheduling problems by using complex network knowledge.

On the relative contributions of multisensory integration and crossmodal exogenous spatial attention to multisensory response enhancement

Two processes that can give rise to multisensory response enhancement (MRE) are multisensory integration (MSI) and crossmodal exogenous spatial attention. It is, however, currently unclear what the relative contribution of each of these is to MRE. We investigated this issue using two tasks that are generally assumed to measure MSI (a redundant target effect task) and crossmodal exogenous spatial attention (a spatial cueing task). One block of trials consisted of unimodal auditory and visual targets designed to provide a unimodal baseline. In two other blocks of trials, the participants were presented with spatially and temporally aligned and misaligned audiovisual (AV) targets (0, 50, 100, and 200ms SOA). In the integration block, the participants were instructed to respond to the onset of the first target stimulus that they detected (A or V). The instruction for the cueing block was to respond only to the onset of the visual targets. The targets could appear at one of three locations: left, center, and right. The participants were instructed to respond only to lateral targets. The results indicated that MRE was caused by MSI at 0ms SOA. At 50ms SOA, both crossmodal exogenous spatial attention and MSI contributed to the observed MRE, whereas the MRE observed at the 100 and 200ms SOAs was attributable to crossmodal exogenous spatial attention, alerting, and temporal preparation. These results therefore suggest that there may be a temporal window in which both MSI and exogenous crossmodal spatial attention can contribute to multisensory response enhancement.

Neuro-oscillatory phase alignment drives speeded multisensory response times: an electro-corticographic investigation.

Even simple tasks rely on information exchange between functionally distinct and often relatively distant neuronal ensembles. Considerable work indicates oscillatory synchronization through phase alignment is a major agent of inter-regional communication. In the brain, different oscillatory phases correspond to low- and high-excitability states. Optimally aligned phases (or high-excitability states) promote inter-regional communication. Studies have also shown that sensory stimulation can modulate or reset the phase of ongoing cortical oscillations. For example, auditory stimuli can reset the phase of oscillations in visual cortex, influencing processing of a simultaneous visual stimulus. Such cross-regional phase reset represents a candidate mechanism for aligning oscillatory phase for inter-regional communication. Here, we explored the role of local and inter-regional phase alignment in driving a well established behavioral correlate of multisensory integration: the redundant target effect (RTE), which refers to the fact that responses to multisensory inputs are substantially faster than to unisensory stimuli. In a speeded detection task, human epileptic patients (N = 3) responded to unisensory (auditory or visual) and multisensory (audiovisual) stimuli with a button press, while electrocorticography was recorded over auditory and motor regions. Visual stimulation significantly modulated auditory activity via phase reset in the delta and theta bands. During the period between stimulation and subsequent motor response, transient synchronization between auditory and motor regions was observed. Phase synchrony to multisensory inputs was faster than to unisensory stimulation. This sensorimotor phase alignment correlated with behavior such that stronger synchrony was associated with faster responses, linking the commonly observed RTE with phase alignment across a sensorimotor network.

Composite faces are not processed holistically: evidence from the Garner and redundant target paradigms

Composite faces fuse the top half of one face with the bottom half of another. These stimuli inflict a strong illusion of a novel face on their viewers, and are often considered to be processed holistically. The current study challenges this holistic view. Here I present provocative evidence from various classic attention paradigms such as the Garner (1974) and the redundant target (Miller, Cognitive Psychology, 14, 247-279, 1982; Townsend & Nozawa, Journal of Mathematical Psychology, 39, 321-359, 1995) tasks showing that face parts are perceived and processed in an analytic rather than holistic fashion. In Experiment 1, composite faces failed to exhibit Garner interference, indicating perfect selective attention to the constituent parts. In Experiments 2 and 3, composite faces failed to exhibit super-capacity with same-identity composites, demonstrating limited or unlimited capacity. This pattern is consistent with analytic perception. Taken together, the results cast serious doubts on the validity of the holistic processing approach. In many respects, the study proposes disillusionment from the composite face illusion. In addition, the study highlights the importance of converging operations, model testability, and individual differences in the study of faces.

Multiplex PCR for Species-Level Identification ofBacillus anthracisand Detection of pXO1, pXO2, and Related Plasmids

The Bacillus anthracis virulence plasmids pXO1 and pXO2 have critical implications for biosafety and select agent status. The proper identification and characterization of B. anthracis and its plasmid profile is important to the biodefense research community. Multiplex PCR was used to simultaneously detect a B. anthracis-specific chromosomal mutation, 4 targets distributed across pXO1, 3 targets distributed across pXO2, and highly conserved regions of the 16S gene, allowing an internal positive control for each sample. The multiplex PCR can produce as many as 9 easily separable and distinguishable amplicons, ranging in size from 188 to 555 bp. The PCR results were used to characterize DNA samples extracted from B. anthracis, other Bacillus species, and other bacterial species from many different genera. With the exception of 2 novel putative plasmids discovered, testing against inclusion and extensive exclusion panels showed 100% correlation to previously published and expected results. Upon testing 29 previously unpublished B. anthracis strains, 10 (34.5%) were pXO1(+)/pXO2(+), 9 (31.0%) were pXO1(+)/pXO2(-), 7 (24.1%) were pXO1(-)/pXO2(+), and 3 (10.3%) were pXO1(-)/pXO2(-). The present work presents a novel 9-target multiplex PCR assay capable of species-level identification of B. anthracis via a unique chromosomal marker and the detection of pXO1 and pXO2 via multiply redundant targets on each.

Modeling violations of the race model inequality in bimodal paradigms: co-activation from decision and non-decision components.

The redundant-signals paradigm (RSP) is designed to investigate response behavior in perceptual tasks in which response-relevant targets are defined by either one or two features, or modalities. The common finding is that responses are speeded for redundantly compared to singly defined targets. This redundant-signals effect (RSE) can be accounted for by race models if the response times do not violate the race model inequality (RMI). When there are violations of the RMI, race models are effectively excluded as a viable account of the RSE. The common alternative is provided by co-activation accounts, which assume that redundant target signals are integrated at some processing stage. However, “co-activation” has mostly been only indirectly inferred and the accounts have only rarely been explicitly modeled; if they were modeled, the RSE has typically been assumed to have a decisional locus. Yet, there are also indications in the literature that the RSE might originate, at least in part, at a non-decisional or motor stage. In the present study, using a distribution analysis of sequential-sampling models (ex-Wald and Ratcliff Diffusion model), the locus of the RSE was investigated for two bimodal (audio-visual) detection tasks that strongly violated the RMI, indicative of substantial co-activation. Three model variants assuming different loci of the RSE were fitted to the quantile reaction time proportions: a decision, a non-decision, and a combined variant both to vincentized group as well as individual data. The results suggest that for the two bimodal detection tasks, co-activation has a shared decisional and non-decisional locus. These findings point to the possibility that the mechanisms underlying the RSE depend on the specifics (task, stimulus, conditions, etc.) of the experimental paradigm.

Genotype to phenotype, the molecular and physiological dimensions of resistance in arthropods

The recent accumulation of molecular studies on mutations in insects, ticks and mites conferring resistance to insecticides, acaricides and biopesticides is reviewed. Resistance is traditionally classified by physiological and biochemical criteria, such as target-site insensitivity and metabolic resistance. However, mutations are discrete molecular changes that differ in their intrinsic frequency, effects on gene dosage and fitness consequences. These attributes in turn impact the population genetics of resistance and resistance management strategies, thus calling for a molecular genetic classification. Mutations in structural genes remain the most abundantly described, mostly in genes coding for target proteins. These provide the most compelling examples of parallel mutations in response to selection. Mutations causing upregulation and downregulation of genes, both in cis (in the gene itself) and in trans (in regulatory processes) remain difficult to characterize precisely. Gene duplications and gene disruption are increasingly reported. Gene disruption appears prevalent in the case of multiple, hetero-oligomeric or redundant targets.

Decomposition of Target Coverage Graph in Wireless Sensor Network

In order to reduce the algorithm complexity of the target coverage problem in Wireless Sensor Network, three kinds of approaches are designed to decrease the network scale, that is, one is deleting the redundant sensor nodes, another is removing the redundant targets, and the third is decomposing the target coverage graph into multiple independent sub graphs. This paper proves that the three approaches are correct, and presents the Construct Independent Sub Graph Algorithm( CISGA) to divide target coverage graph. Experiment results show that CISGA can reduce 30% of network scale and greatly reduce the algorithm complexity of target coverage problem.

Effects of aging and distractors on detection of redundant visual targets and capacity: do older adults integrate visual targets differently than younger adults?

In the redundant target effect, participants respond faster with two (redundant) targets. We compared the magnitude of this effect in younger and older adults, with and without distractors, in a simple visual-detection task. We employed additional measures that allow non-parametric assessment of performance (Townsend's capacity coefficient) and parametric estimates (Linear Ballistic Accumulator model). Older participants' latencies were slower, especially in the presence of distractors, and their calculated capacity indicators increased with distractors. Parametric estimates indicated that these increases were generated by the older adults' increased difficulty in inhibiting the distractors, and not the results of either improved detection of redundant-targets, or of a generalized slowing of processing.

Оптимизация алгебраической модели конструктивной логики

The authors proposed and evaluated options of optimization of the algebraic model of constructive logic, designed to construct multichannel non-linear mathematical model often used in Russia in the in-depth analysis in medicine and biology. In the basis of optimization of this model are procedures for finding duplicate cases (rows base), relevant to the achievement of goals, and excluding those resulting components that are duplicated other cases the resulting components.
 
 Procedures for reviewing the results of the components of a top-down or bottom-up and comparing the numbers corresponding to achievement of objectives are the basis of optimization. If all the numbers viewing the resulting component will be present in other watched the resulting components, then it is removed as redundant. As a result of identifying and eliminating redundant coatings target lines are reducing the number of resulting parts. Reduction of number of resulting components is achieved by identifying and eliminating redundant coatings target lines.
 
 The results of two variants of optimization of mathematical model are shown on the example of the mathematical model identification features of the method of oxygen therapy in the treatment of oncological pathology. The authors suggested the possibility of practical use of various optimization algorithms to choose model with a minimal number of components of the resulting/

Bilateral and two-item advantage in subitizing.

Subitizing refers to people's ability to enumerate small sets of items fast and accurately. The present study examined if the speed and scope of subitizing is improved when the items to be enumerated are presented bilaterally across hemifields rather than unilaterally in a single hemifield. Such an effect, known as the bilateral field advantage, has been observed in a number of other visual tasks. A second aim was to examine whether the speed of subitizing could be explained by the speed it takes to detect the items to be enumerated, as simple reaction times to multiple stimuli are known to be faster than responses to individual items (known as the redundant target effect, RTE). The results revealed a bilateral field advantage even for enumerating two items. Moreover, the two item condition was the optimal subitizing condition - even enumerating one single item took longer - but this effect was not due to the RTE. In fact, the RTE negatively correlated with the speed of enumerating the same stimuli.

The influence of cueing on attentional focus in perceptual decision making.

Selective attention has been known to play an important role in decision making. In the present study, we combined a cueing paradigm with a redundant-target detection task to examine how attention affects the decision process when detecting the redundant targets. Cue validity was manipulated in two experiments. The results showed that when the cue was 50 % valid in one experiment, the participants adopted a parallel self-terminating processing strategy, indicative of a diffuse attentional focus on both target locations. When the cue was 100 % valid in the second experiment, all of the participants switched to a serial self-terminating processing strategy, which in our study indicated focused attention to a single target location. This study demonstrates the flexibility of the decision mechanism and highlights the importance of top-down control in selecting a decision strategy.

Rare genetic diseases with human lean and/or starvation phenotype open new avenues for obesity and type II diabetes treatment.

Treatments of obesity and type II diabetes target often gene functions involved in appetite-satiety, fat and carbohydrate metabolism or thermogenesis. None of these, have provided efficient drug therapy due to a large number of genes involved in weight and energy management, the redundancy of biochemical pathways and the environmental factors. Here I discuss a new approach based on studies of genes/proteins that are associated with human "lean or starvation" phenotype that became very rare in the course of evolution. This approach has led to the identification of the congenital enteropeptidase deficiency gene and the Anderson's Disease gene as a potential targets for obesity and type II diabetes treatment. The advantages of these targets are: 1) they are expressed exclusively in the intestine; 2) they are peripheral targets as opposed to systemic targets; 3) they are not redundant targets. These targets open new hopes for the development of novel drugs for the treatment of common metabolic syndrome.

Unlike in Clinical Blindsight Patients, Unconscious Processing of Chromatic Information Depends on Early Visual Cortex in Healthy Humans

Large amount of data concerning the neural mechanisms that mediate unconscious vision come from cortically blind patients who can process stimuli presented in their blind visual field. How well the findings generalize to neurologically healthy humans remains open. Using transcranial magnetic stimulation (TMS), we studied whether chromatic processing depends on the early visual cortex in healthy participants. We employed a phenomenon called the redundant target effect (RTE): simple reaction times to two stimuli are faster than to one stimulus, even when one of the stimuli is presented outside consciousness. The RTE produced by chromatically defined stimuli disappeared when the contralateral stimulus of two bilateral stimuli was suppressed from consciousness. In contrast to studies on blindsight patients, the results imply that the early visual cortex is necessary for the processing of chromatic information in neurologically healthy humans.

Multisensory Integration and Attention in Developmental Dyslexia

Developmental dyslexia affects 5%-10% of the population, resulting in poor spelling and reading skills. While there are well-documented differences in the way dyslexics process low-level visual and auditory stimuli, it is mostly unknown whether there are similar differences in audiovisual multisensory processes. Here, we investigated audiovisual integration using the redundant target effect (RTE) paradigm. Some conditions demonstrating audiovisual integration appear to depend upon magnocellular pathways, and dyslexia has been associated with deficits in this pathway; so, we postulated that developmental dyslexics ("dyslexics" hereafter) would show differences in audiovisual integration compared with controls. Reaction times (RTs) to multisensory stimuli were compared with predictions from Miller's race model. Dyslexics showed difficulty shifting their attention between modalities; but such "sluggish attention shifting" (SAS) appeared only when dyslexics shifted their attention from the visual to the auditory modality. These results suggest that dyslexics distribute their crossmodal attention resources differently from controls, causing different patterns in multisensory responses compared to controls. From this, we propose that dyslexia training programs should take into account the asymmetric shifts of crossmodal attention.

Redundancy gain in semantic categorisation

Redundancy gain refers to the performance enhancements often associated with the presentation of redundant versus single targets (for example, faster, more accurate, or more forceful responses). Though predominantly observed in relatively simple tasks (e.g., stimulus detection), there have been some efforts to investigate similar phenomena in tasks involving higher level processing. We conducted three experiments aimed at determining (a) whether a redundancy gain would be evident in a task unambiguously requiring higher level processing (the semantic categorisation of visually-presented lexical stimuli), and (b) if so, what accounts might be appropriate to explain such findings. We found that redundancy gains are observed in such tasks, and we conclude that both coactivation and race models can account for these gains.

Interactions between Identity and Emotional Expression in Face Processing across the Lifespan: Evidence from Redundancy Gains.

We tested how aging affects the integration of visual information from faces. Three groups of participants aged 20–30, 40–50, and 60–70 performed a divided attention task in which they had to detect the presence of a target facial identity or a target facial expression. Three target stimuli were used: (1) with the target identity but not the target expression, (2) with the target expression but not the target identity, and (3) with both the target identity and target expression (the redundant target condition). On nontarget trials the faces contained neither the target identity nor expression. All groups were faster in responding to a face containing both the target identity and emotion compared to faces containing either single target. Furthermore the redundancy gains for combined targets exceeded performance limits predicted by the independent processing of facial identity and emotion. These results are held across the age range. The results suggest that there is interactive processing of facial identity and emotion which is independent of the effects of cognitive aging. Older participants demonstrated reliably larger size of the redundancy gains compared to the young group that reflect a greater experience with faces. Alternative explanations are discussed.

Comparison by Simulation of Energy Consumption and WSN Lifetime for LEACH and LEACH-SM

Extending the period of operation (lifetime) of wireless sensor networks (WSNs) is one of the most critical issues. Lifetime limitations are due to limited energy resources. Available research results reveal that significant improvement in WSN lifetime can be achieved by using spares (spare nodes). At the moment of WSN deployment, the minimum required coverage of WSN targets is assured by primaries (primary nodes). Spares, if activated, would provide an above-threshold (more than required), redundant target coverage, so they can be switched off initially. They are ready to be switched on when any primary exhausts its energy. The spares must be properly managed. Mismanagement includes redundant and above-threshold coverage, which increase transmission of redundant data to cluster heads (collecting information from regular nodes, that is, primary nodes that are not cluster heads). Therefore, mismanaged spares can shorten WSN lifetime instead of extending it. We measured WSN lifetime by simulating the behavior of a single node. This paper presents the impact of spares and duration of the Nap interval of cluster heads on the WSN lifetime. We generate results based on different executions representing different scenarios.

The electrophysiological locus of the redundant target effect on visual discrimination in a dual singleton search task

Task performance can be enhanced by the addition of extra information to a visual environment in which observers search for a target stimulus. One example of such information is the repetition of the searched-for stimulus; a form of target redundancy. In the present study, the electrophysiological correlates of such target redundancy were investigated in a visual discrimination task. Observers were asked to look for targets in displays that always contained two salient singletons (tilted lines; targets and/or nontargets) against a background of vertical distractor lines. Displays contained either two redundant targets, two nontargets, or a single target and nontarget, at opposite sides of the visual field. Search was most efficient when two targets were shown, and effects of target redundancy were observed on the event-related potential as well. Target redundancy modulated the anterior N2, and the P3 in both an early and a late window. The results are compatible with models of visual attention that support a relatively late (i.e., central or decisional) locus of redundancy processing.

Fiber tract-driven topographical mapping (FTTM) reveals microstructural relevance for interhemispheric visuomotor function in the aging brain.

We present a novel approach - DTI-based fiber tract-driven topographical mapping (FTTM) - to map and measure the influence of age on the integrity of interhemispheric fibers and challenge their selective functions with measures of interhemispheric integration of lateralized information. This approach enabled identification of spatially specific topographical maps of scalar diffusion measures and their relation to measures of visuomotor performance. Relative to younger adults, older adults showed lower fiber integrity indices in anterior than posterior callosal fibers. FTTM analysis identified a dissociation in the microstructural-function associates between age groups: in younger adults, genu fiber integrity correlated with interhemispheric transfer time, whereas in older adults, body fiber integrity was correlated with interhemispheric transfer time with topographical specificity along left-lateralized callosal fiber trajectories. Neural co-activation from redundant targets was evidenced by fMRI-derived bilateral extrastriate cortex activation in both groups, and a group difference emerged for a pontine activation cluster that was differently modulated by response hand in older than younger adults. Bilateral processing advantages in older but not younger adults further correlated with fiber integrity in transverse pontine fibers that branch into the right cerebellar cortex, thereby supporting a role for the pons in interhemispheric facilitation. In conclusion, in the face of compromised anterior callosal fibers, older adults appear to use alternative pathways to accomplish visuomotor interhemispheric information transfer and integration for lateralized processing. This shift from youthful associations may indicate recruitment of compensatory mechanisms involving medial corpus callosum fibers and subcortical pathways.