Stopping Rules for Audiological Ascending Test Procedures: Computer Simulation Evaluation

1986 ◽  
Author(s):  
Lynne Marshall ◽  
Thomas E. Hanna
Keyword(s):  
Computer Simulation ◽  
Stopping Rules ◽  
Test Procedures ◽  
Simulation Evaluation

Evaluation of Stopping Rules for Audiological Ascending Test Procedures Using Computer Simulations

1989 ◽  
Vol 32 (2) ◽  
pp. 265-273 ◽  
Author(s):  
Lynne Marshall ◽  
Thomas E. Hanna
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Psychometric Function ◽  
Computer Simulations ◽  
Stopping Rules ◽  
Response Criterion ◽  
Small Decrease ◽  
Test Procedures ◽  
Minimum Number ◽  
Audiological Test

Stopping rules for ascending audiological test procedures were evaluated by Monte Carlo simulation. The stopping rules differed in the minimum number of responses required at a level, whether these responses occurred on half or a majority of the ascending series, and whether all or only the most recent ascending series were considered. For all procedures, shallow psychometric function slopes yielded estimated thresholds closer to the level giving 50% detection than did steeper slopes, which yielded estimated thresholds roughly 2.5 dB above the level corresponding to 50% on the psychometric function. Shallow slopes also resulted in decreased reliability across threshold measurements, an increased number of trials required for threshold estimates, and a higher proportion of measurements that had to be repeated. Stopping rules using a two-response criterion were faster than those using a three-response criterion, with only a small decrease in reliability. Among stopping rules using the same number of responses for criterion, differences were seen primarily in efficiency for shallow slopes, particularly for procedures using a three-response rather than a two-response criterion for stopping. Results from these simulations should be useful to standards groups.

Characterization of Modulated Structure Through Structure Images and their Computer Simulation

1990 ◽  
Vol 48 (1) ◽  
pp. 70-71
Author(s):  
Kiyomichi Nakai ◽  
Yusuke Isobe ◽  
Chiken Kinoshita ◽  
Kazutoshi Shinohara
Keyword(s):  
Computer Simulation ◽  
High Resolution ◽  
Spherical Aberration ◽  
High Resolution Electron Microscopy ◽  
Basic Mechanism ◽  
Objective Lens ◽  
Specimen Thickness ◽  
Transmitted Beam ◽  
Modulated Structure ◽  
Resolution Electron

Induced spinodal decomposition under electron irradiation in a Ni-Au alloy has been investigated with respect to its basic mechanism and confirmed to be caused by the relaxation of coherent strain associated with modulated structure. Modulation of white-dots on structure images of modulated structure due to high-resolution electron microscopy is reduced with irradiation. In this paper the atom arrangement of the modulated structure is confirmed with computer simulation on the structure images, and the relaxation of the coherent strain is concluded to be due to the reduction of phase-modulation.Structure images of three-dimensional modulated structure along <100> were taken with the JEM-4000EX high-resolution electron microscope at the HVEM Laboratory, Kyushu University. The transmitted beam and four 200 reflections with their satellites from the modulated structure in an fee Ni-30.0at%Au alloy under illumination of 400keV electrons were used for the structure images under a condition of the spherical aberration constant of the objective lens, Cs = 1mm, the divergence of the beam, α = 3 × 10-4 rad, underfocus, Δf ≃ -50nm and specimen thickness, t ≃ 15nm. The CIHRTEM code was used for the simulation of the structure image.

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