A multi-source information fusion method for ship target recognition based on bayesian inference and evidence theory

The ship target recognition (STR) is greatly related to the battlefield situation awareness, which has recently gained prominence in the military domains. With the diversification and complexity of military missions, ship targets are mostly performed in the form of formations. Therefore, using the formation information to improve the accuracy of the ship target type recognition is worth studying. To effectively identify ship target type, we in this paper jointly consider the ship dynamic, formation, and feature information to propose a STR method based on Bayesian inference and evidence theory. Specifically, we first calculate the ship position distance matrix and the directional distance matrix with the Dynamic Time Warping (DTW) and the difference-vector algorithm taken into account. Then, we use the two distance matrices to obtain the ship formation information at different distance thresholds by the hierarchical clustering method, based on which we can infer the ship type. Thirdly, formation information and other attribute information are as nodes of the Bayesian Network (BN) to infer the ship type. Afterward, we can convert the recognition results at different thresholds into body of evidences (BOEs) as multiple information sources. Finally, we fuse the BOEs to get the final recognition. The proposed method is verified in simulation battle scenario in this paper. The simulation results demonstrate that the proposed method achieves performance superiority as compared with other ship recognition methods in terms of recognition accuracy.

Efficacy of computational predictions of the functional effect of idiosyncratic pharmacogenetic variants

Background Pharmacogenetic variation is important to drug responses through diverse and complex mechanisms. Predictions of the functional impact of missense pharmacogenetic variants primarily rely on the degree of sequence conservation between species as a primary discriminator. However, idiosyncratic or off-target drug-variant interactions sometimes involve effects that are peripheral or accessory to the central systems in which a gene functions. Given the importance of sequence conservation to functional prediction tools—these idiosyncratic pharmacogenetic variants may violate the assumptions of predictive software commonly used to infer their effect. Methods Here we exhaustively assess the effectiveness of eleven missense mutation functional inference tools on all known pharmacogenetic missense variants contained in the Pharmacogenomics Knowledgebase (PharmGKB) repository. We categorize PharmGKB entries into sub-classes to catalog likely off-target interactions, such that we may compare predictions across different variant annotations. Results As previously demonstrated, functional inference tools perform variably across the complete set of PharmGKB variants, with large numbers of variants incorrectly classified as ‘benign’. However, we find substantial differences amongst PharmGKB variant sub-classes, particularly in variants known to cause off-target, type B adverse drug reactions, that are largely unrelated to the main pharmacological action of the drug. Specifically, variants associated with off-target effects (hence referred to as off-target variants) were most often incorrectly classified as ‘benign’. These results highlight the importance of understanding the underlying mechanism of pharmacogenetic variants and how variants associated with off-target effects will ultimately require new predictive algorithms. Conclusion In this work we demonstrate that functional inference tools perform poorly on pharmacogenetic variants, particularly on subsets enriched for variants causing off-target, type B adverse drug reactions. We describe how to identify variants associated with off-target effects within PharmGKB in order to generate a training set of variants that is needed to develop new algorithms specifically for this class of variant. Development of such tools will lead to more accurate functional predictions and pave the way for the increased wide-spread adoption of pharmacogenetics in clinical practice.

The development of foraging organization

In foraging tasks multiple targets must be found within a single display. The targets can be of one or more types, typically surrounded by numerous distractors. Visual attention has traditionally been studied with single target search tasks but adding more targets to the search display results in several additional measures of interest, such as how attention is oriented to different features and locations over time. We measured foraging among five age groups: Children in grades 1, 4, 7, and 10, as well as adults, using both simple feature foraging tasks and more challenging conjunction foraging tasks, with two target types per task. We assessed participants’ foraging organization, or systematicity when selecting all the targets within the foraging display, on four measures: Intertarget distance, number of intersections, best-r, and the percentage above optimal path length (PAO). We found that foraging organization increases with age, in both simple feature-based foraging and more complex foraging for targets defined by feature conjunctions, and that feature foraging was more organized than conjunction foraging. Separate analyses for different target types indicated that children’s, and to some extent adults’, conjunction foraging consisted of two relatively organized foraging paths through the display where one target type is exhaustively selected before the other target type is selected. Lastly, we found that the development of foraging organization is closely related to the development of other foraging measures. Our results suggest that measuring foraging organization is a promising avenue for further research into the development of visual orienting.

Visual foraging and executive functions: A developmental perspective

In the past few years, interest in visual foraging, where participants search for multiple targets at a time, has increased, as such tasks may provide a richer picture of visual attention than traditional single-target visual search tasks. Little is known about visual foraging in childhood, so we tested 67 6th grade Icelandic children (mean age = 11.80 years, SD = 0.30 years; 36 girls) on a foraging task involving multiple targets of different types, also measuring three subdomains of executive functioning: inhibition, attentional flexibility, and working memory. The foraging results were then compared to findings from a previous study on younger children (66 children aged 4-7 years). The results show that foraging ability improves dramatically between the preschool and middle school years, and that this improvement reflects greater ease with switching between target types. The older children showed foraging patterns previously seen for adults: randomly switching between target templates during feature foraging, but exhaustively foraging for a single target type before switching during conjunction foraging. Younger children, conversely, tended to stick with the same target type for long runs during feature foraging. Switch costs were also much lower for the older children, resulting in faster and more efficient foraging. Lastly, a connection was established between foraging ability and both working memory and attentional flexibility, but not inhibition. Our study shows that foraging is a promising field of study to further our knowledge of visual attention, how it changes throughout the lifespan, and how it is connected to other cognitive functions.

Does Sentence-Level Coarticulation Affect Speech Recognition in Noise or a Speech Masker?

Purpose Three experiments were conducted to better understand the role of between-word coarticulation in masked speech recognition. Specifically, we explored whether naturally coarticulated sentences supported better masked speech recognition as compared to sentences derived from individually spoken concatenated words. We hypothesized that sentence recognition thresholds (SRTs) would be similar for coarticulated and concatenated sentences in a noise masker but would be better for coarticulated sentences in a speech masker. Method Sixty young adults participated ( n = 20 per experiment). An adaptive tracking procedure was used to estimate SRTs in the presence of noise or two-talker speech maskers. Targets in Experiments 1 and 2 were matrix-style sentences, while targets in Experiment 3 were semantically meaningful sentences. All experiments included coarticulated and concatenated targets; Experiments 2 and 3 included a third target type, concatenated keyword-intensity–matched (KIM) sentences, in which the words were concatenated but individually scaled to replicate the intensity contours of the coarticulated sentences. Results Regression analyses evaluated the main effects of target type, masker type, and their interaction. Across all three experiments, effects of target type were small (< 2 dB). In Experiment 1, SRTs were slightly poorer for coarticulated than concatenated sentences. In Experiment 2, coarticulation facilitated speech recognition compared to the concatenated KIM condition. When listeners had access to semantic context (Experiment 3), a coarticulation benefit was observed in noise but not in the speech masker. Conclusions Overall, differences between SRTs for sentences with and without between-word coarticulation were small. Beneficial effects of coarticulation were only observed relative to the concatenated KIM targets; for unscaled concatenated targets, it appeared that consistent audibility across the sentence offsets any benefit of coarticulation. Contrary to our hypothesis, effects of coarticulation generally were not more pronounced in speech maskers than in noise maskers.

Axiomatic Results for Weighted Allocation Rules under Multiattribute Situations

In many interactive environments, operators may have to deal with different work objectives at the same time. In a realistic context, such as differences in the target type to be addressed, or changes in the behavior of other operators, operators may therefore have to cope with by adopting different work levels (strategies) at any given time. On the other hand, the importance or influence brought by operators may vary depending on many subjective and objective factors, such as the size of the constituency represented by a congressman, and the bargaining power of a business personnel which may vary. Therefore, it is reasonable that weights are apportioned to operators and arbitrary usability should be distributed according to these weights under various working levels and multiattribute situations. In pre-existing results for allocation rules, weights might be always apportioned to the “operators” or the “levels” to modify the differences among the operators or its working levels respectively. By applying weights to the operators and its working levels (strategies) simultaneously, we adopt the maximal marginal variations among working level (strategy) vectors to propose an allocation rule under multiattribute situations. Furthermore, we introduce some axiomatic outcomes to display the rationality for this weighted allocation rule. By replacing weights to be maximal marginal variations, a generalized index is also introduced.

The efficiency of visual search for a frequently changed target is preserved in older adults

Visual search is a psychological function integral to most people’s daily lives. The extent to which visual search efficiency, and in particular the ability to use top-down attention in visual search, changes across the lifespan has been the focus of ongoing research. Here we sought to understand how the ability to frequently and dynamically change the target in a conjunction search task was affected by ageing. To do this, we compared visual search performance of a group of younger and older adults under conditions in which the target type was determined by a cue and could change on trial-to-trial basis (Intermixed), versus when the target type was fixed for a block of trials (Blocked). Although older adults were overall slower at the conjunction visual search task, and both groups were slower in the Intermixed compared with the Blocked Condition, older adults were not disproportionately affected by the Intermixed relative to the Blocked conditions. These results indicate that the ability to frequently change the target of visual search is preserved in older adults. This conclusion is consistent with an emerging consensus that many aspects of visual search and top-down contributions to it are preserved across the lifespan. It is also consistent with a growing body of work which challenges the neurocognitive theories of ageing that predict sweeping deficits in complex top-down components of cognition.

Guidance-Based Motion Planning of Autonomous Systems

Motion planning is a significant stage in the control of autonomous systems. As an alternative method, guidance approach is proposed for the motion planning of those systems. In guided munitions, guidance laws determine the success of the guidance systems designed to steer systems such as missiles and guided bombs towards predefined targets. The guidance laws designated according to determinative agents such as the firing position of the munition, target type, and operational requirements try to provide the munition with arriving at the target point even under the disturbing effects. In this study, the applicability of the guidance laws to autonomous systems is investigated in a manner similar to the approach for the guided munitions. For this purpose, the motion planning of the selected robotic arm, tracked land vehicle, and quadrotor is tried to be performed in order to move them to predefined target points. Having designed the control systems compatible to the selected guidance laws for the considered systems, the corresponding guidance scheme is constructed. Eventually, after conducting the relevant computer simulations, it is observed that the desired target chase can be made in a successive manner for all cases.