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Signal detection theory

Haofeng Wang, Shudong Chen, Shuang Zhang, Zhiwen Yuan, Haiyang Zhang, Dong Fang, Jun Zhu
Portable transient electromagnetic (TEM) systems can be well adapted to various terrains, including mountainous, woodland, and other complex terrains. They are widely used for the detection of unexploded ordnance (UXO). As the core component of the portable TEM system, the sensor is constructed with a transmitting coil and a receiving coil. Based on the primary field of the transmitting coil and internal noise of the receiving coil, the design and testing of such a sensor is described in detail. Results indicate that the primary field of the transmitting coil depends on the diameter, mass, and power of the coil...
November 17, 2017: Sensors
Babak Sharif, Amir Homayoun Jafari
Biosignals are considered as important sources of data for diagnosing and detecting abnormalities, and modeling dynamics in the body. These signals are usually analyzed using features taken from time and frequency domain. In theory' these dynamics can also be analyzed utilizing Poincaré plane that intersects system's trajectory. However' selecting an appropriate Poincaré plane is a crucial part of extracting best Poincaré samples. There is no unique way to choose a Poincaré plane' because it is highly dependent to the system dynamics...
November 16, 2017: Australasian Physical & Engineering Sciences in Medicine
Julian Cruz-Borbolla, Esteban Garcia-Ochoa, Jayanthi Narayanan, Pablo Maldonado-Rivas, Thangarasu Pandiyan, José M Vásquez-Pérez
The capacity of 2,6-bis[((2-pyridylmethyl)oxy)methyl)]pyridine (BPMMP) to inhibit the corrosion of mild carbon steel in HCl was analyzed. In a polarization study, both the cathodic and anodic currents were appreciably decreased in the presence of BPMMP, suggesting that this ligand is effective at inhibiting corrosion at the metal surface. This conclusion is consistent with the results of impedance analysis, where only one time constant corresponding to one depressed capacitive loop was detected, and the diameter of the impedance plot was directly related to the concentration of BPMMP...
November 15, 2017: Journal of Molecular Modeling
Daeheum Cho, Jeremy R Rouxel, Markus Kowalewski, Jin Yong Lee, Shaul Mukamel
With the advancement of high quality X-ray sources, it is now possible to create a molecular movie by following the electronic dynamics in real-time and real-space through time resolved X-ray diffraction. Here, we employ real-time time-dependent density functional theory (RT-TDDFT) to simulate the electronic dynamics after an impulse core or valence ionization in the glycine-phenylalanine (GF) dipeptide. The simulation yields the time-evolving dipole moment, the charge density, and the time-resolved X-ray diffraction signals...
November 15, 2017: Journal of Chemical Theory and Computation
J Peter Leeds
The theory of cognitive acuity (TCA) treats the response options within items as signals to be detected and uses psychophysical methods to estimate the respondents' sensitivity to these signals. Such a framework offers new methods to construct and score situational judgment tests (SJT). Leeds (2012) defined cognitive acuity as the capacity to discern correctness and distinguish between correctness differences among simultaneously presented situation-specific response options. In this study, SJT response options were paired in order to offer the respondent a two-option choice...
November 9, 2017: Behavior Research Methods
Jakub Kaminský, Jakub Chalupský, Petr Štěpánek, Jan Kříž, Petr Bouř
Absorption and magnetic circular dichroism (MCD) spectroscopies are powerful and simple methods to discriminate among various compounds. Polycyclic aromatic hydrocarbons provide particularly strong signal, which, for example, facilitates their detection in the environment. However, interpretation of the spectra is often based on quantum-chemical simulations, providing a limited precision only. In the present work, we use time-dependent density functional theory and complete active space second-order perturbation theories to understand spectral features observed in a series of naphthalene, anthracene, phenanthrene, and three larger compounds...
November 17, 2017: Journal of Physical Chemistry. A
Koryna Lewandowska, Barbara Wachowicz, Tadeusz Marek, Halszka Oginska, Magdalena Fafrowicz
Across a wide range of tasks, cognitive functioning is affected by circadian fluctuations. In this study, we investigated diurnal variations of working memory performance, taking into account not only hits and errors rates, but also sensitivity (d') and response bias (c) indexes (established by signal detection theory). Fifty-two healthy volunteers performed four experimental tasks twice - in the morning and in the evening (approximately 1 and 10 h after awakening). All tasks were based on Deese-Roediger-McDermott paradigm version dedicated to study working/short-term memory distortions...
November 7, 2017: Chronobiology International
Courtney Weston, Jonathan Smuts, James X Mao, Kevin A Schug
Stable-isotopically-labeled internal standards are commonly incorporated in methods for trace analysis that utilize mass spectrometric detection. They closely mimic the physicochemical properties of the analyte, but their signal is easily differentiable based on a change in molecular mass. To investigate the potential to transfer methods incorporating such internal standards for analysis by vacuum ultraviolet detection, a study was conducted to compare the spectral shape (from 125 to 240nm) of stable-isotopically-labeled compounds with their non-labeled counterparts...
January 15, 2018: Talanta
Jiabo Di, Hong Yang, Beihai Jiang, Zaozao Wang, Jiafu Ji, Xiangqian Su
Sporadic synchronous colorectal cancer (CRC) refers to more than one primary tumor detected in a single patient at the time of the first diagnosis without predisposition of cancer development. Given the same genetic and microenvironment they raise, sporadic synchronous CRC is a unique model to study CRC tumorigenesis. We performed whole exome sequencing in 32 fresh frozen tumor lesions from 15 patients with sporadic synchronous CRC to compare their genetic alterations. This approach identified ubiquitously mutated genes in the range from 0...
November 6, 2017: International Journal of Cancer. Journal International du Cancer
Jefferson G Filgueiras, Uilson B da Silva, Giovanni Paro, Marcel N d'Eurydice, Márcio F Cobo, Eduardo R deAzevedo
We present a simple (1)H NMR approach for characterizing intermediate to fast regime molecular motions using (1)H time-domain NMR at low magnetic field. The method is based on a Goldmann Shen dipolar filter (DF) followed by a Mixed Magic Sandwich Echo (MSE). The dipolar filter suppresses the signals arising from molecular segments presenting sub kHz mobility, so only signals from mobile segments are detected. Thus, the temperature dependence of the signal intensities directly evidences the onset of molecular motions with rates higher than kHz...
October 20, 2017: Journal of Magnetic Resonance
Elisabet Aguiló, Artur J Moro, Raquel Gavara, Ignacio Alfonso, Yolanda Pérez, Francesco Zaccaria, Célia Fonseca Guerra, Marc Malfois, Clara Baucells, Montserrat Ferrer, João Carlos Lima, Laura Rodríguez
The reaction of the gold polymers containing bipyridyl and terpyridyl units, [Au(C≡CC15H10N3)]n and [Au(C≡CC10H7N2)]n, with the water-soluble phosphines 1,3,5-triaza-7-phosphatricyclo[]decane and 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane gives rise to the formation of four gold(I) alkynyl complexes that self-assemble in water (H2O) and dimethyl sulfoxide (DMSO), through different intermolecular interactions, with an impact on the observed luminescence displayed by the supramolecular assemblies...
October 28, 2017: Inorganic Chemistry
Lukas Burkhardt, Michael Holzwarth, Bernd Plietker, Matthias Bauer
Two hydride catalysts [Fe(CO)(dppp)H(NO)] (dppp = 1,3-bis(diphenylphosphino)propane) and [Fe(CO)H(NO)(PPh3)2] in comparison with nonhydride analogues [Fe(dppe)(NO)2] (dppe = 1,3-bis(diphenylphosphino)ethane) and [Fe(NO)2(PPh3)2] are investigated with a combination of valence-to-core X-ray emission spectroscopy (VtC-XES) and high-energy resolution fluorescence detected X-ray absorption near-edge structure (HERFD-XANES). To fully understand the experiments and to obtain precise information about molecular levels being involved in the spectral signals, time-dependent density functional theory (TD-DFT) calculations and ground state density functional theory (DFT) calculations are necessary...
November 6, 2017: Inorganic Chemistry
P Johnson, J Moriarty, G Peskir
The real-time detection of changes in a noisily observed signal is an important problem in applied science and engineering. The study of parametric optimal detection theory began in the 1930s, motivated by applications in production and defence. Today this theory, which aims to minimize a given measure of detection delay under accuracy constraints, finds applications in domains including radar, sonar, seismic activity, global positioning, psychological testing, quality control, communications and power systems engineering...
August 13, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Junghyun Wee, Drew Hackney, Philip Bradford, Kara Peters
Fiber Bragg grating (FBG) sensors are typically spot-bonded onto the surface of a structure to detect ultrasonic waves in laboratory demonstrations. However, to protect the rest of the optical fiber from any environmental damage during real applications, bonding the entire length of fiber, called continuous bonding, is commonly done. In this paper, we investigate the impact of continuously bonding FBGs on the measured Lamb wave signal. In theory, the ultrasonic wave signal can bi-directionally transfer between the optical fiber and the plate at any adhered location, which could potentially produce output signal distortion for the continuous bonding case...
September 1, 2017: Applied Optics
Xiuyan Zhang, Wanying Gu, Chunlei Jiang, Bingkun Gao, Peng Chen
This study proposes a novel algorithm based on the multiple self-mixing interference (MSMI) theory to measure the velocity of a remote target without contact. The principle of MSMI is presented and the corresponding formulas for velocity measurement are derived. Fast Fourier transform is applied to detect signal frequency and calculate velocity values. A low-cost, compact, and easy-to-operate experimental setup is also constructed. Experiments are conducted to validate the correctness of our algorithm. This algorithm can improve resolution more easily than conventional self-mixing interference methods...
August 10, 2017: Applied Optics
Pete C Trimmer, Sean M Ehlman, John M McNamara, Andrew Sih
Signal detection theory has influenced the behavioural sciences for over 50 years. The theory provides a simple equation that indicates numerous 'intuitive' results; e.g. prey should be more prone to take evasive action (in response to an ambiguous cue) if predators are more common. Here, we use analytical and computational models to show that, in numerous biological scenarios, the standard results of signal detection theory do not apply; more predators can result in prey being less responsive to such cues...
October 25, 2017: Proceedings. Biological Sciences
Manuel Rausch, Sebastian Hellmann, Michael Zehetleitner
How do human observers determine their degree of belief that they are correct in a decision about a visual stimulus-that is, their confidence? According to prominent theories of confidence, the quality of stimulation should be positively related to confidence in correct decisions, and negatively to confidence in incorrect decisions. However, in a backward-masked orientation task with a varying stimulus onset asynchrony (SOA), we observed that confidence in incorrect decisions also increased with stimulus quality...
October 17, 2017: Attention, Perception & Psychophysics
Chonghui Li, Aihua Liu, Chao Zhang, Minghong Wang, Zhen Li, Shicai Xu, Shouzhen Jiang, Jing Yu, Cheng Yang, Baoyuan Man
The physical phenomenon, surface-enhanced Raman scattering (SERS), is mainly based on the local electromagnetic fields enhancement located at the nano-gaps between metal nanostructures attributed to localized surface plasmon resonance. Therefore, nano-gaps are very important for obtaining high-density hot spots and optimal and uniform SERS signals. However, it remains a challenge to form the three-dimensional ultra-narrow nano-gaps. Here, a gyrus-inspired Gyrus-SERS substrate was fabricated with the nanostructure of Ag gyrus/graphene/Au film using an extremely simple method...
August 21, 2017: Optics Express
Lan Luo, Xiaodong Qiu, Linguo Xie, Xiong Liu, Zhaoxue Li, Zhiyou Zhang, Jinglei Du
In this paper, a method to improve the precision of prism-coupler-based surface plasmon resonance (SPR) sensors using weak-value amplification (WVA) is presented. A general theory model to describe the post-selected SPR sensing system is established and the polarization-dependent amplitude and phase evolutions induced by the SPR are regarded as the weak interactions in the WVA formalism. As a consequence of WVA, the detected signal can be enhanced with respect to the technical noise which is dependent on the post-selected light intensity...
September 4, 2017: Optics Express
Casey Inez Canfield, Baruch Fischhoff
Phishing risk is a growing area of concern for corporations, governments, and individuals. Given the evidence that users vary widely in their vulnerability to phishing attacks, we demonstrate an approach for assessing the benefits and costs of interventions that target the most vulnerable users. Our approach uses Monte Carlo simulation to (1) identify which users were most vulnerable, in signal detection theory terms; (2) assess the proportion of system-level risk attributable to the most vulnerable users; (3) estimate the monetary benefit and cost of behavioral interventions targeting different vulnerability levels; and (4) evaluate the sensitivity of these results to whether the attacks involve random or spear phishing...
October 11, 2017: Risk Analysis: An Official Publication of the Society for Risk Analysis
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