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Signal detection theory describes how an observer makes decisions about weak, uncertain, or ambiguous events or signals. It is widely applied in psychology, medicine, and other related fields. This book describes the theory, explains its mathematical basis, and shows how to separate the observer's sensitivity to a signal from his or her tendency to say “yes” or “no.” Both detection of an event and discrimination between two events are treated. Chapters 1-4 describe the basic form of the signal-detection model and how to use it; Chapters 5-7 extend the model to different procedures such as identification of a signal; Chapters 8-10 expand it to other methods and distributions; and Chapter 11 describes the statistical treatment of detection data.

This book shows you how to adopt data-driven techniques for the problem of radar detection, both per se and in combination with model-based approaches. In particular, the focus is on space-time adaptive target detection against a background of interference consisting of clutter, possible jammers, and noise. It is a handy, concise reference for many classic (model-based) adaptive radar detection schemes as well as the most popular machine learning techniques (including deep neural networks) and helps you identify suitable data-driven approaches for radar detection and the main related issues. You'll learn how data-driven tools relate to, and can be coupled or hybridized with, traditional adaptive detection statistics; understand fundamental concepts, schemes, and algorithms from statistical learning, classification, and neural networks domains. The book also walks you through how these concepts and schemes have been adapted for the problem of radar detection in the literature and provides you with a methodological guide for the design, illustrating different possible strategies. You'll be equipped to develop a unified view, under which you can exploit the new possibilities of the data-driven approach even using simulated data. This book is an excellent resource for Radar professionals and industrial researchers, postgraduate students in electrical engineering and the academic community.

What do inferring what a person is thinking or feeling, judging a defendant's guilt, and navigating a dimly lit room have in common? They involve perceptual uncertainty (e.g., a scowling face might indicate anger or concentration, for which different responses are appropriate) and behavioral risk (e.g., a cost to making the wrong response). Signal detection theory describes these types of decisions. In this tutorial, we show how incorporating the economic concept of utility allows signal detection theory to serve as a model of optimal decision making, going beyond its common use as an analytic method. This utility approach to signal detection theory clarifies otherwise enigmatic influences of perceptual uncertainty on measures of decision-making performance (accuracy and optimality) and on behavior (an inverse relationship between bias magnitude and sensitivity optimizes utility). A \"utilized\" signal detection theory offers the possibility of expanding the phenomena that can be understood within a decision-making framework.

The minimum mean square error (MMSE) signal detection algorithm is near-optimal for uplink multi-user large-scale multiple-input–multiple-output (MIMO) systems, but involves matrix inversion with high complexity. It is firstly proved that the MMSE filtering matrix for large-scale MIMO is symmetric positive definite, based on which a low-complexity near-optimal signal detection algorithm by exploiting the Richardson method to avoid the matrix inversion is proposed. The complexity can be reduced from 𝒪(K3) to 𝒪(K2), where K is the number of users. The convergence proof of the proposed algorithm is also provided. Simulation results show that the proposed signal detection algorithm converges fast, and achieves the near-optimal performance of the classical MMSE algorithm.

In studies of animal cognition, the influence of background masking noise on responses to any particular stimulus are often overlooked. In fish, there is little understanding of their response to targeted acoustic stimuli in the presence of high intensity (Sound Pressure Levels) environmental masking noise commonly experienced in the wild. In a controlled laboratory study, Signal Detection Theory was used to investigate coarse (startles) and fine-scale (swimming speed, group cohesion and alignment) responses of common carp ( Cyprinus carpio ) to pulsed tonal signals (170 Hz) differing in their signal-to-noise ratio (low, intermediate, or high) above either background ambient, or masking noise (fixed intensity Gaussian white noise: 120–3000 Hz). In comparison to independent control groups, fish exhibited a startle response, reduced their average swimming speed, increased group cohesion, and became more aligned at the onset of tonal stimuli under ambient noise. Signal discriminability was reduced under the masking noise conditions, with coarse-scale behavioural responses largely absent, and fine-scale responses suppressed but positively related to signal-to-noise ratio. This study enhances understanding of the potential ecological consequences of anthropogenically generated noise on the behaviour of fish and may help in the development of more effective environmental impact mitigation technologies, such as behavioural guidance systems, that use sound to induce avoidance.

According to signal detection theoretical analyses, visual signals occurring at a cued location are detected more accurately, whereas frequently occurring ones are reported more often but are not better distinguished from noise. However, conventional analyses that estimate sensitivity and bias by comparing true- and false-positive rates offer limited insights into the mechanisms responsible for these effects. Here, we reassessed the prior influences of signal probability and relevance on visual contrast detection using a reverse-correlation technique that quantifies how signal-like fluctuations in noise predict trial-to-trial variability in choice discarded by conventional analyses. This approach allowed us to estimate separately the sensitivity of true and false positives to parametric changes in signal energy. We found that signal probability and relevance both increased energy sensitivity, but in dissociable ways. Cues predicting the relevant location increased primarily the sensitivity of true positives by suppressing internal noise during signal processing, whereas cues predicting greater signal probability increased both the frequency and the sensitivity of false positives by biasing the baseline activity of signal-selective units. We interpret these findings in light of \"predictive-coding\" models of perception, which propose separable top-down influences of expectation (probability driven) and attention (relevance driven) on bottom-up sensory processing.

Zylberberg et al. [Zylberberg, Barttfeld, & Sigman (Frontiers in Integrative Neuroscience, 6; 79, 2012 ), Frontiers in Integrative Neuroscience 6 :79] found that confidence decisions, but not perceptual decisions, are insensitive to evidence against a selected perceptual choice. We present a signal detection theoretic model to formalize this insight, which gave rise to a counter-intuitive empirical prediction: that depending on the observer’s perceptual choice, increasing task performance can be associated with decreasing metacognitive sensitivity (i.e., the trial-by-trial correspondence between confidence and accuracy). The model also provides an explanation as to why metacognitive sensitivity tends to be less than optimal in actual subjects. These predictions were confirmed robustly in a psychophysics experiment. In a second experiment we found that, in at least some subjects, the effects were replicated even under performance feedback designed to encourage optimal behavior. However, some subjects did show improvement under feedback, suggesting the tendency to ignore evidence against a selected perceptual choice may be a heuristic adopted by the perceptual decision-making system, rather than reflecting inherent biological limitations. We present a Bayesian modeling framework that explains why this heuristic strategy may be advantageous in real-world contexts.

The perceived replication crisis and the reforms designed to address it are grounded in the notion that science is a binary signal detection problem. However, contrary to null hypothesis significance testing (NHST) logic, the magnitude of the underlying effect size for a given experiment is best conceptualized as a random draw from a continuous distribution, not as a random draw from a dichotomous distribution (null vs. alternative). Moreover, because continuously distributed effects selected using a P < 0.05 filter must be inflated, the fact that they are smaller when replicated (reflecting regression to the mean) is no reason to sound the alarm. Considered from this perspective, recent replication efforts suggest that most published P < 0.05 scientific findings are “true” (i.e., in the correct direction), with observed effect sizes that are inflated to varying degrees. We propose that original science is a screening process, one that adopts NHST logic as a useful fiction for selecting true effects that are potentially large enough to be of interest to other scientists. Unlike original science, replication science seeks to precisely measure the underlying effect size associated with an experimental protocol via large-N direct replication, without regard for statistical significance. Registered reports are well suited to (often resource-intensive) direct replications, which should focus on influential findings and be published regardless of outcome. Conceptual replications play an important but separate role in validating theories. However, because they are part of NHST-based original science, conceptual replications cannot serve as the field’s self-correction mechanism. Only direct replications can do that.

Bearing fault is the most likely to occur in mechanical fault, and stochastic resonance (SR), as a noise enhanced signal processing tool, can find mechanical faults as early as possible, so as to avoid larger problems. However, most of the existing research methods are based on the first-order Langevin equation. According to the previous studies of many scholars, the weak signal detection ability of the second-order system is better than that of the first-order system, and the coupled system also has better performance due to the addition of the control system. So, in order to detect the fault signal more easily, a second-order coupled tristable stochastic resonance system (SCTSR) based on the adaptive genetic algorithm (AGA) is proposed, it is an improvement on improving the first-order coupled tristable stochastic resonance system (FCTSR). First, based on the fourth-order Runge–Kutta algorithm (F-RK), the performances of monostable, bistable and tristable control systems to SCTSR are compared, it is verified that the monostable system has the best performance as SCTSR’s control system. Secondly, the equivalent potential function of SCTSR is derived, and the influences of each system parameters on it are researched. The output signal-to-noise ratio gain ( SNRG ) is chosen as a measure to verify that SCTSR’s performance is better than that of FCTSR, and the influences of parameters on SNRG are discussed. SCTSR and FCTSR are used to detect low-, high- and multi-frequency cosine signals combined with AGA. The simulation results are compared with the wavelet transform method, which proves the performance superiority of SR, and also prove that SCTSR is easier to detect weak signals and has a stronger de-noising ability. Finally, SCTSR and FCTSR are applied in bearing fault detection under Gaussian white noise and trichotomous noise. The results also prove that SCTSR can get larger peaks and SNRG , and it is easier to detect fault signals. This proves that SCTSR’s performance is superior that of other methods in bearing fault detection, and has better engineering application value.

Researchers dispute the cause of errors in high Go, low No Go target detection tasks, like the Sustained Attention to Response Task (SART). Some researchers propose errors in the SART are due to perceptual decoupling, where a participant is unaware of stimulus identity. This lack of external awareness causes an erroneous response. Other researchers suggest the majority of the errors in the SART are instead due to response leniency, not perceptual decoupling. Response delays may enable a participant who is initially unaware of stimulus identity, perceptually decoupled, to become aware of stimulus identity, or perceptually recoupled. If, however, the stimulus presentation time is shortened to the minimum necessary for stimulus recognition and the stimulus is disrupted with a structured mask, then there should be no time to enable perception to recouple even with a response delay. From the perceptual decoupling perspective, there should be no impact of a response delay on performance in this case. Alternatively if response bias is critical, then even in this case a response delay may impact performance. In this study, we shortened stimulus presentation time and added a structured mask. We examined whether a response delay impacted performance in the SART and tasks where the SART’s response format was reversed. We expected a response delay would only impact signal detection theory bias, c, in the SART, where response leniency is an issue. In the reverse formatted SART, since bias was not expected to be lenient, we expected no impact or minimal impact of a response delay on response bias. These predictions were verified. Response bias is more critical in understanding SART performance, than perceptual decoupling, which is rare if it occurs at all in the SART.