The effect of diotic and dichotic level-randomization on the binaural masking-level difference

Detection thresholds for tones in narrow-band noise were measured for two binaural configurations: N(o)S(o) and N(o)S(pi). The 30-Hz noise band had a mean overall level of 65 dB SPL and was centered on 250, 500, or 5000 Hz. Signals and noise were simultaneously gated for 500, 110, or 20 ms. Three conditions of level randomization were tested: (1) no randomization; (2) diotic randomization--the stimulus level (common to both ears) was randomly chosen from an uniformly distributed 40-dB range every presentation interval; and (3) dichotic randomization--the stimulus levels for each ear were each independently and randomly chosen from the 40-dB range. Regardless of binaural configuration, level randomization had small effects on thresholds at 500 and 110 ms, implying that binaural masking-level differences (BMLDs) do not depend on interaural level differences for individual stimuli. For 20-ms stimuli, both diotic and dichotic randomization led to markedly poorer performance than at 500- and 110-ms durations; BMLDs diminished with no randomization and dichotic randomization but not with diotic randomization. The loss of BMLDs at 20 ms, with degrees-of-freedom (2WT) approximately 1, implies that changes in intracranial parameters occurring during the course of the observation interval are necessary for BMLDs when mean-level and mean-intracranial-position cues have been made unhelpful.     

Effects of target-masker contextual similarity on the multimasker penalty in a three-talker diotic listening task

In many multitalker listening tasks, the degradation in performance that occurs when the number of interfering talkers increases from one to two is much larger than would be predicted from the corresponding decrease in the signal-to-noise ratio (SNR). In this experiment, a variety of contextually-relevant speech maskers, contextually-irrelevant speech maskers and non-speech maskers were used to examine the impact that the characteristics of the interfering sound sources have on the magnitude of this "multimasker penalty." The results show that a significant multimasker penalty only occurred in cases where two specific conditions were met: 1) the stimulus contained at least one contextually-relevant masker that could be confused with the target; and 2) the signal-to-noise ratio of the target relative to the combined masker stimulus was less than 0 dB. Remarkably, in cases where one masker was contextually relevant, the specific characteristics of the second masker had virtually no impact on the size of the multimasker penalty. Indeed, when the results were corrected for random guessing, there was essentially no difference in performance between conditions with three contextually-relevant talkers and those with two contextually-relevant talkers and one irrelevant talker. The results of a second experiment suggest that the listeners are generally able to hear keywords spoken by all three talkers even in situations where the multimasker penalty occurs, implying that the primary cause of the penalty is a degradation in the listener's ability to use prosodic cues and voice characteristics to link together words spoken at different points in the target phrase.     

Binaural processing of noisy stimuli: internal/external noise ratios for diotic and dichotic stimuli

A set of ten digitized statistically similar Gaussian maskers was used in one-internal tone-in-noise detection experiments under diotic (NoSo) and dichotic (NoS pi) interaural conditions. Stimulus/response matrices were generated for each masker in the presence or absence of a target 500-Hz tone. For both NoSo and NoS pi, nonparametric analyses show that response probabilities and sensitivities vary significantly across noise waveforms, indicating a considerable external noise component in subject response variability. A parametric model is developed that maps individual stimulus waveforms onto a decision axis, facilitating evaluation of internal/external noise variance ratios. For both NoSo and NoS pi, internal and external noise variance are of similar magnitude.     

Within-ear and across-ear interference in a dichotic cocktail party listening task: effects of masker uncertainty

Increases in masker variability have been shown to increase the effects of informational masking in non-speech listening tasks, but relatively little is known about the influence that masker uncertainty has on the informational components of speech-on-speech masking. In this experiment, listeners were asked to extract information from a target phrase that was presented in their right ear while ignoring masking phrases that were presented in the same ear as the target phrase and in the ear opposite the target phrase. The level of masker uncertainty was varied by holding constant or "freezing" the talkers speaking the masking phrases, the semantic content used in the masking phrases, or both the talkers and the semantic content in the masking phrases within each block of 120 trials. The results showed that freezing the semantic content of the masking phrase in the target ear was the only reduction in masker uncertainty that ever resulted in a significant improvement in performance. Providing feedback after each trial improved performance overall, but did not prevent the listeners from making incorrect responses that matched the content of the frozen target-ear masking phrase. However, removing the target-ear contents corresponding to the masking phrase from the response set resulted in a dramatic improvement in performance. This suggests that the listeners were generally able to understand both of the phrases presented to the target ear, and that their incorrect responses in the task were almost entirely a result of their inability to determine which words were spoken by the target talker.     

Frequency resolution as a function of hearing threshold level and age

Frequency resolution ability was measured using a psychoacoustical tuning curve (PTC) or a notch-noise technique in two population samples. The first sample incorporated 1764 subjects with various degrees of sensorineural hearing impairment and ranging in age from 17-80 years. The second sample included 240 subjects aged between 50 and 75 years, carefully balanced in terms of impairment and age to avoid confounding between these two variables. In both samples, frequency resolution ability declined with increasing hearing threshold level (HTL), as measured by either method. In a subsample tested with both methods, the correlation between the two was only modest. After accounting for HTL, there was a minor dependence of frequency resolution on age, older subjects having poorer frequency resolution once HTL had been accounted for. No addition to the explained variance was achieved by taking sex, occupational group, or audiogram slope into account. Despite the documented reproducibility of the measures, much of the variance in the frequency resolution measurements remained unrelated to HTL or age.     

Numerical resolution of the modified Langevin equation using a differential expression: Application to the Jiles magnetostriction law of approach

The Langevin equation is classically used to model the anhysteretic magnetization curve. A modified version of this equation has been introduced by Jiles to take into account the effects of magnetostriction on the anhysteretic magnetization behavior when a ferromagnetic material undergoes mechanical stresses. The numerical resolution of the modified Langevin equation is usually performed with a root-finding algorithm. In this paper, a differential form of the modified Langevin equation is proposed, allowing a faster numerical resolution.     

How to measure the decoherence of a micromaser field under well controlled conditions

We discuss a possible realization of a quantum register with controllable decoherence in terms of /0> and /1> photon number states of a micromaser field. It is shown how to create in the Jaynes-Cummings model a superposition state of /0> and /1> photon number states inside a closed micromaser cavity. The loss of phase coherence between these two states can subsequently be measured by a second probe atom monitoring the decoherence of the field. A technique is proposed for forming the superposition of number states /0> and /1> using the time structure of the Rabi oscillation. The proposed method avoids problems with stray fields at the cavity holes, which disturb the coherence of the atomic superposition, and offers a way to study how the coupling strength to the environment influences the decoherence rate, displaying the robustness of physical qubits and the fidelity of quantum computations.     

Frequency resolution and amplitude accuracy of the coherent optical spectrum analyzer with a swept local oscillator

We present a model for coherent optical spectrum analysis that relates the key parameters of frequency resolution, power uncertainty, and sweep speed. The theoretical model is compared with experimental results obtained from spectral measurements of an external-cavity laser.     

Global structure of the superstring partition function and resolution of the supermoduli measure ambiguity

We investigate the global structure of the fermionic string partition function on the supermoduli space M_g^sup. In particular we show how the recently discovered moduli total-derivative ambiguity is due to a non-trivial cocycle on M_g^sup, present if an atlas of coordinates of M_g^sup can be found, whose transition functions contain even, nilpotent components. We find a correction to the usual Berezin measure on M_g^sup, given by the so-called Rothstein volume form, that eliminates the above boundary ambiguities of the supermoduli measure at any genus. We discuss also the so-called theorem of holomorphic factorization in this particular case and its relation to the physical requirement of modular invariance.     

First-principle proof of the modified collision boundary conditions for the hard-sphere system

A fundamental issue lying at the foundation of classical statistical mechanics is the determination of the collision boundary conditions that characterize the dynamical evolution of multi-particle probability density functions (PDF) and are applicable to systems of hard-spheres undergoing multiple elastic collisions. In this paper it is proved that, when the deterministic N-body PDF is included in the class of admissible solutions of the Liouville equation, the customary form of collision boundary conditions adopted in previous literature becomes physically inconsistent and must actually be replaced by suitably modified collision boundary conditions.     

使用CCD测量玻璃管内液体界面位置的灵巧测量头

本文介绍一种使用线阵ＣＣＤ进行玻璃管内液位测量的光电测量头。与其他ＣＣＤ尺寸测量的光学系统不同，本文依据不同的液体具有不同的折射率，提出利用柱形容器中液体的聚光特性，得到两种不同液体的分界面在线阵ＣＣＤ上清晰的像。     

Frequency bandwidth and potential resolution of optical modulators exploiting a multi-phonon light scattering in crystals

We consider physical conditions for realizing the Bragg regime of one-, two-, and three-phonon scattering of light in optically anisotropic crystalline materials. The exact and closed analytical models for describing these regimes are developed and solved. The performed analysis takes into account an opportunity of realizing 100% efficiency of light scattering in these regimes. Possible applications lie in the fields of creating large-aperture modulators of light. In connection with this, the problems of optimizing the frequency bandwidths and potential resolution of such modulators are studied. Reasonable attention is paid to the contribution of acoustic anisotropy to frequency bandwidth. The analytical results are illustrated by computer simulations and compared with proof-of-principle experimental data related to a multi-phonon light scattering in a tellurium dioxide crystal.     

Decisive factors for realizing atomic-column resolution using STEM and EELS

We demonstrate atomic-column imaging by scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS). The silicon atomic-columns of a beta-Si3N4 (0 0 1) specimen are clearly resolved. The atomic-site dependence and the energy-loss dependence of the spatial resolution are elucidated on the basis of the experimental results and multislice calculations. We describe two decisive factors for realizing atomic-column imaging in terms of localization in elastic and inelastic scattering. One is the channeling of the incident probe due to dynamical diffraction, which has atomic-site dependence. The other is the localization in inelastic scattering; in addition to the energy-loss dependence of delocalization, we point out its dependence on the offset energy from the ionization energy, i.e., an additional localization factor concerning the Bethe surface. The present atomic-column observation of the Si-L core-loss image indicates that the local approximation, which can be interpreted intuitively, is achievable under appropriate experimental conditions, such as high-energy-loss, a small convergence angle and a large collection angle (e.g., 400 eV, 15 and 30 mrad, respectively).     

Decisive factors for realizing atomic-column resolution using STEM and EELS

We demonstrate atomic-column imaging by scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS). The silicon atomic-columns of a β-Si₃N₄ (0 0 1) specimen are clearly resolved. The atomic-site dependence and the energy-loss dependence of the spatial resolution are elucidated on the basis of the experimental results and multislice calculations. We describe two decisive factors for realizing atomic-column imaging in terms of localization in elastic and inelastic scattering. One is the channeling of the incident probe due to dynamical diffraction, which has atomic-site dependence. The other is the localization in inelastic scattering; in addition to the energy-loss dependence of delocalization, we point out its dependence on the offset energy from the ionization energy, i.e., an additional localization factor concerning the Bethe surface. The present atomic-column observation of the Si-L core-loss image indicates that the local approximation, which can be interpreted intuitively, is achievable under appropriate experimental conditions, such as high-energy-loss, a small convergence angle and a large collection angle (e.g., 400 eV, 15 and 30 mrad, respectively).     

An extremely narrow UV pulse generation using a micro- and nano-ring system for pico-lithographic resolution

We propose a new technique of an extremely narrow ultraviolet (UV) pulse width generation for pico-lithography technology using a nonlinear ring resonator system. A system consists of three micro- and a nano-optical ring resonators, which can be used to generate the 50 pm (10⁻¹² m) optical spectral width at the ultraviolet wavelength. By using a soliton pulse with a pulse width of 50 ns, 1 W peak power, center wavelength at 1550 nm, after the soliton pulse is launched into a first ring device, the chaotic pulses are generated within the first ring. The chaotic filtering behaviors are performed by using the second and third ring devices, whereas the extremely short pulse, i.e. narrow spectral width, can be generated by using the extended nano-ring device. The broad spectrum of the harmonic waves is generated and filtered, especially the generation of third harmonic wave, which is known as the ultraviolet wavelength, is achieved, which is capable of forming pico-lithographic resolution. Results obtained have shown that the generation of the spectral width of 50 pm at a wavelength of 511.125 nm, with peak power at 35 mW is achieved.     

Parametric characterisation of a chaotic attractor using the two scale Cantor measure

A chaotic attractor is usually characterised by its multifractal spectrum which gives a geometric measure of its complexity. Here we present a characterisation using a minimal set of independent parameters which is uniquely determined by the underlying process that generates the attractor. The method maps the f(α) spectrum of a chaotic attractor on to that of a general two scale Cantor measure. We show that the mapping can be done in practice with reasonable accuracy for many of the standard chaotic attractors. In order to implement this procedure, we also propose a generalisation of the standard equations for the two scale Cantor set in one dimension to that in higher dimensions. Another interesting result we have obtained both theoretically and numerically is that, the f(α) characterisation gives information only up to two scales, even when the underlying process generating the multifractal involves more than two scales.     

Studies on the drift properties and spatial resolution using a microMEGAS-equipped time projection chamber

R&D studies on the performance as well as on the gas properties of the microMEGAS-based time projection chamber with standard readout were carried out in June 2005 using 4 GeV/c pion beam in a magnetic field from 0 to 1 T at the proton synchrotron beam line at KEK, Japan. Analysis of the electron drift velocity, diffusion constant and point resolution of padrow measurement for MicroMEGAS TPC filled with 95% argon and 5% isobutane gas are presented. The underlying physical mechanism which determines the optimal TPC performance are briefly discussed. Preliminary measurements of gas properties and spatial resolution in close agreement with the analytical calculation and MAGBOLTZ simulation are summarized and presented in this paper.