Binary Detection Theory Research Articles

Tamper-Indicating Quantum Seal

Technical means for identifying when tampering occurs is a critical part of many containment and surveillance technologies. Conventional fiber optic seals provide methods for monitoring enclosed inventories, but they are vulnerable to spoofing attacks based on classical physics. We address these vulnerabilities with the development of a quantum seal that offers the ability to detect the intercept-resend attack using quantum integrity verification. Our approach represents an application of entanglement to provide guarantees in the authenticity of the seal state by verifying it was transmitted coherently. We implement these ideas using polarization-entangled photon pairs that are verified after passing through a fiber-optic channel testbed. Using binary detection theory, we find the probability of detecting inauthentic signals is greater than 0.9999 with a false alarm chance of $10^{-9}$ for a 10 second sampling interval. In addition, we show how the Hong-Ou-Mandel effect concurrently provides a tight bound on redirection attack, in which tampering modifies the shape of the seal. Our measurements limit the tolerable path length change to sub-millimeter disturbances. These tamper-indicating features of the quantum seal offer unprecedented security for unattended monitoring systems.

BER Analysis and Verification of EBPSK System in AWGN Channel

The extended binary phase shift keying (EBPSK) transmission system with ultra narrow bandwidth has excellent BER performance, which raises many doubts with the researchers. Therefore, on the premise of the existence of a special filter that can transform the modulated phase information into amplitude information, the theoretical BER formula of EBPSK system in Additive White Gaussian Noise (AWGN) channel has been deduced. This paper gives the theoretical values of the parameters in the above BER formula and discusses the effects of parameters on BER firstly. Then the paper shows that the special impacting filter satisfies the above assumption, therefore, in the frame of binary detection theory, the excellent performance of high-efficiency EBPSK system can be explained and the correction of the theoretical BER formula can be validated.

BIOLOGICALLY PLAUSIBLE BSDT RECOGNITION OF COMPLEX IMAGES: THE CASE OF HUMAN FACES

On the basis of recent binary signal detection theory (BSDT), optimal recognition algorithms for complex images are constructed and their optimal performance are calculated. A methodology for comparing BSDT predictions and measured human performance is developed and applied to explaining particular face recognition experiment. The BSDT makes possible computer codes with recognition performance better than that in humans, its fundamental discreteness is consistent with the experiment. Related neurobiological and behavioral effects are briefly discussed.

Classroom demonstration—Generating an ROC curve from the energy detection of signals in random noise

Students enrolled in “Underwater Acoustics and Sonar” at the Naval Academy benefit from a “hands‐on” demonstration of binary detection theory. The relationships between the respective probabilities of detection, miss, false alarm, and null [P(D), P(MISS), P(FA), P(NULL)] are examined for different thresholds. Two loudspeakers, driven respectively by random noise and a pure tone, simulate the acoustical environment. The output of a microphone is sent through an analog multiplier and a low‐pass filter, which act as the detector. An Apple IIe computer with a digital oscilloscope card displays the output and performs the probability density function on the processed signal. PDFs of (a) noise alone and (b) noise plus a signal are used to generate the receiver operating characteristic (ROC) curve. [Work supported by the Naval Academy Research Council.]

Photon counting and Laguerre detection (Corresp.)

In this correspondence maximum-likelihood binary detection theory is applied to an incoherent optical system model employing photodetectors governed by Laguerre counting statistics. It is shown that a maximum-likelihood Laguerre detector corresponds to a count comparison over each signaling interval. Laguerre error probabilities are presented and compared with those for Poisson counting.