Tracing Mode Research Articles

Temporal factors for vibrotactile letter reading.

Using an apparent-motion mode, the psychophysical effect of apparent movement was introduced for tactile letter reading. This mode reduces time for the tracing mode. Five temporal parameters were examined for application to actual communication. 4 subjects recognized words composed of 3 to 7 Japanese letters in about 5 seconds.

書字モードと筆圧・筆速の関係について

Two experiments were conducted to investigate the relations between handwriting mode (tracing and copying) and handwriting pressure-velocity. In experiment I, kindergartners (N=20) and undergraduate students (N=20) were required to write a Kanji five times in each mode employing handwriting pressure device (TAKEI KIKI co. make). In experiment II, undergraduate students (N=20) were required to write a Hangul character (Korean), unfamiliar character to subjects, using the same procedure. The results showed that there was a significant difference in handwriting pressure-velocity between kindergartner and undergraduate groups with regard to the handwriting mode. Discussed on the basis of the model of information processing on handwriting behavior (Schmidt, 1982; Stelmach, 1982), the results of two experiments suggested that the tracing mode made the burden too heavy for the response execution stage in that model as compared with copying mode. It was concluded that handwriting in tracing mode was a more difficult task than the copying mode for kindergartners.

Direct imaging of ionic pathways in stratum corneum using scanning electrochemical microscopy

We have used a scanning electrochemical microscope (SECM) to identify the routes of iontophoretic flux of ionic species (Fe 2+ and Fe 3+) across excised hairless mouse skin. SECM has been used both in the imaging mode, where large two-dimensional areas (∼1 mm 2) are surveyed to identify regions of high ionic flux, and in the quantitative single trace mode, where flux profiles over a fixed feature are repeatedly measured along one dimension. SECM images indicate that a significant portion of ion flux occurs through shunt pathways in the skin. Images reveal that the spatial density of shunt pathways is greater than that of hair follicles, by up to an order of magnitude, indicating that hair follicles represent a minor contribution to shunt pathways in the skin. A quantitative comparison of the relative fluxes of Fe 2+ and Fe 3+ through a single pore indicates that Fe 2+ is transported at a significantly larger rate than Fe 3+. These data represent, to our knowledge, the first direct, chemical-specific identification of transport pathways in skin.

Interactive graphics simulation with multi-level collision algorithm

Abstract An interactive, realistic computer graphics simulation package for robotic manipulators has been developed. Three PUMA robot manipulators and two existing robotic workcells have been implemented as specific applications. Interaction with the program is possible through user-friendly pop-up menus, information-display fields, and a unique on-screen teach pendant simulation. An interpreter for the robotic programming language VALII has been incorporated to interface with the graphics interface. The interpreter features a program-line trace mode to ease detection of logical errors in the control program. A multilevel collision-detection algorithm has been developed and implemented. The response time of the algorithm is a function of the proximity of the modelled manipulator to obstacles in the work space. It corresponds to the actual operation of the real robotic workcell.

A FILTER, DELAY AND SPREAD TECHNIQUE FOR 3D DMO1

The calculation of dip moveout involves spreading the amplitudes of each input trace along the source-receiver axis followed by stacking the results into a 3D zero-offset data cube. The offset-traveltime (x–t) domain integral implementation of the DMO operator is very efficient in terms of computation time but suffers from operator aliasing. The log-stretch approach, using a logarithmic transformation of the time axis to force the DMO operator to be time invariant, can avoid operator aliasing by direct implementation in the frequency-wavenumber (f–k) domain. An alternative technique for log-stretch DMO corrections using the anti-aliasing filters of the f–k approach in the x-log t domain will be presented. Conventionally, the 2D filter representing the DMO operator is designed and applied in the f–k domain. The new technique uses a 2D convolution filter acting in single input/multiple output trace mode. Each single input trace is passed through several 1D filters to create the overall DMO response of that trace. The resulting traces can be stacked directly in the 3D data cube. The single trace filters are the result of a filter design technique reducing the 2D problem to several ID problems. These filters can be decomposed into a pure time-delay and a low-pass filter, representing the kinematic and dynamic behaviour of the DMO operator. The low-pass filters avoid any incidental operator aliasing. Different types of low-pass filters can be used to achieve different amplitude-versus-offset characteristics of the DMO operator.

Application of a perspective cursor as a 3D locator device

The functionality of a 3D cursor is described. It can be used as a 3D locator device in such applications as interactive path planning (robotics), motion specification in 3D computer animation design, and wireframe modelling. With respect to the last of these applications, it is important that the cursor can be used either in constructive mode, as a set of three mutually orthogonal rulers, or in trace mode to copy a 2D perspective view of an object while reconstruction its 3D shape. As a special feature, the cursor may be equipped with a mirror of locations in scenes that are (partially) symmetric, but also allows 3D symmetric objects to be entered from 2D (perspective) views, while making use of symmetry as a clue for reconstructing z-coordinates.

Growth factor- and phorbol ester-induced changes in cell morphology analyzed by digital image processing

We have developed the computer-aided image processing analysis to visualize and quantitate the cell motility and morphological changes in living cultured cells. The effect of growth factors on cell motility and morphology has been analyzed by this method. Insulin, insulin-like growth factor-I (IGF-I), and epidermal growth factor (EGF) elicited membrane rufflings in rat embryo fibroblast 3Y1 cells as well as in human epidermoid carcinoma KB cells. Insulin and IGF-I also induced ruffling membranes in Balb/c-3T3 cells. The quantitative analysis by the programmed trace mode of the AVEC system has shown that the motion of the membrane rufflings was observed within 2 min, reached the maximum level within 4–8 min, and rapidly decreased within 10–15 min after the addition of these growth factors. The analysis also revealed the temperature- and growth factor concentration-dependent changes in the motion of membrane rufflings elicited by these growth factors. 12- O-Tetradecanoylphorbol-13-acetate, one of the well-known tumor promoters, rapidly induced cell rounding in Balb/c-3T3 cells. This change of cell morphology could be also quantified by the trace mode analysis. The fluorescent phalloidin staining experiment indicated that these growth factor- or phorbol ester-induced morphological changes were accompanied by the reorganization of filamentous actin. Furthermore, we were able to visualize actin stress fibers in living EBTr cells by enhancing the video image and to follow the reduction of stress fibers induced by cytochalasin B without any fixation or fluorescent probes.

Temporal factors in the discrimination of tonal sequences.

Human observers were asked to judge whether or not two sequences of eight or more tones had the same serial pattern of frequencies. The temporal envelopes of the sequences were manipulated by randomly varying the tone durations or intertone gaps. In the correlated condition, the temporal envelopes of the sequences were varied across trials; the two sequences within each trial had the same temporal envelope. In the uncorrelated condition, the temporal envelopes were varied both across and within trials; every sequence had a unique temporal pattern. Performance in the uncorrelated condition decreased with increased variability in the temporal envelope. Performance in the correlated condition was independent of temporal variability, but decreased with increases in the time interval between the onsets of the two sequences. This pattern of results is consistent with an extension of a model of auditory discrimination developed by Durlach and Braida [J. Acoust. Soc. Am. 46, 372-383 (1969)], in which two processing modes are postulated: a trace mode and a context mode. When the tonal sequences had unique temporal patterns, context mode processing was dominant; when the sequences had identical temporal patterns, trace mode processing was preferred. The effect of variables such as the number of tones, the tone duration, the time gap between tones, and the time interval between sequences was consistent with the predictions of the discrimination model.

A dynamic very high-level debugger for low-level microprograms

Microcode debuggers may be classified according to the following three criteria: static or dynamic output, the level of debugging, and the type of debugging facilities provided. A very high level interactive debugger that supports dynamic debugging of microcode written for the Perkin-Elmer 3220 is described in this paper. The system allows the user to debug microcode at a very high level because the microarchitecture of the machine can be displayed in the format conceived by the user. The display is dynamic in that the user sees the flow of data as it occurs during the execution of microinstructions. The system supports the usual debugging facilities including setting breakpoints, executing in step or continuous modes, executing in trace mode, examining and changing the contents of memory locations and registers, and restarting the microprogram at an earlier location. But, these facilities are greatly enhanced because the output of the debugger is graphical and dynamic.

Uniformly spaced field‐aligned ionization ducts

MF and HF radio wave signals transmitted from topside sounders can often become trapped in magnetic‐field‐aligned ionization ducts located approximately vertically below the satellite. The resulting traces observed on ionograms are called combination mode traces. A number of cases of combination mode traces observed with the ISIS topside sounders were studied for passes over mid‐ and low‐latitude regions which exhibited distinguishable, nearly uniformly spaced traces on the ionograms typical of this type of propagation in the frequency range above 1 MHz. Associated extraordinary vertical and ducted traces were also evident in all cases. The ducted trace is interpreted as due to propagation in a duct encompassing the satellite at the time of measurement, whereas the combination mode traces are interpreted as due to ducts located well below the satellite. The simultaneous presence of a ducted trace and combination mode traces suggests the presence of a parallel system of ducts that are field aligned. On interpreting the ionograms for events studied by ray tracing, it was found that the ducts are separated by as much as 70 km transverse to their field alignment. The data indicate that, at times, the ducts may exist down to the F peak and may extend into the conjugate region as well. A multiplicity of ducts with such large, relatively uniform separations was not previously appreciated, and the mechanism for creating them in this fashion is not clear. One possibility for the even spacing of these irregularities is that they result from acoustic gravity waves at lower altitudes. Possible relationships to other geophysical phenomena, particularly equatorial phenomena, are discussed.

Intensity perception. XIII. Perceptual anchor model of context-coding.

In our preliminary theory of intensity resolution [e.g., see N. I. Durlach and L. D. Braida, J. Acoust. Soc. Am. 46, 372-383 (1969)], two modes of memory operation are postulated: the trace mode and the context-coding mode. In this paper, we present a revised model of the context-coding mode which describes explicitly a process by which sensations are coded relative to the context and which predicts a resolution edge effect [L. D. Braida and N. I. Durlach, J. Acoust. Soc. Am. 51, 483-502 (1972); J. E. Berliner, L. D. Braida, and N. I. Durlach, J. Acoust. Soc. Am. 61, 1256-1267 (1977)]. The sensation arising from a given stimulus presentation is coded by determining its distance from internal references or perceptual anchors. The noise in this process, combined with the sensation noise, constitutes the limitation on resolution in the model. In the revised model the probability density functions of the decision variable are not precisely Gaussian (and cannot be expressed analytically in closed form). This paper outlines the predictions of the model for one-interval paradigms and for fixed-level two-interval paradigms and derives estimates of the values of model parameters.

Memory modes and perceptual anchors in categorical perception

A theory of intensity perception developed by Durlach and Braida [J. Acoust. Sac. Am. 46, 372–383 (1969), et seq.] is applied to data from categorical perception experiments. According to the theory, two memory modes are used in processing perceptual continua. In the trace mode, observers compare stimuli with the memory traces of other stimuli, and performance is limited by the inter‐stimulus interval. In the context mode, observers compare stimuli to perceptual anchors, and performance is limited by the stimulus range. Analysis of existing speech and nonspeech data reveals that stimulus domains differ in (a) the amount of trace variance, (b) the amount of context‐coding variance, and (c) the existence and location of anchors; but no single parameter captures the categorical/continuous distinction. Memory variances and anchor locations can be estimated from experiments in which fixed‐level discrimination, as well as identification and roving‐level discrimination, is measured. Among the few experiments with categorically perceived continua that have used the critical fixed‐level condition are some in which discrimination peaks arise from anchors, and others in which they reflect regions of high basic sensitivity. [Work supported by NIH.]

Discrimination of binary tone sequences

Subjects were presented with two sequences of tones, e.g., HLLHHHLL, HLHLHHLL. The tones were either 669 Hz or 1621 Hz. Subjects were instructed to respond “same” if the same serial pattern of high and low tones were repeated in the second sequence. They were to ignore any variation in the time between the tones. Performance was assessed in a variety of task conditions. The variables studied included: the number of tones, the mean time separation between tones, the magnitude of variability (jitter) in the time between tones, the correlation between the jitter pattern in the two sequences, the pattern variability in the sequences, and the serial position of pattern differences between the sequences. The results are interpreted using an extension of the auditory memory model developed by Durlach and Braida [J. Acoust. Soc. Am. 46, 372–383 (1969)]. This model postulates two independent memory modes, a trace (time‐dependent) mode, and a context coding (set‐size‐dependent) mode. The data provide general support for the extension of the dual mode model to this task. [Work supported by NSF.]

Control modes and task complexity in tracing and handwriting performance

Two common modes of handwriting control are tracing and free-hand writing. Two experiments were conducted to examine writing time and writing pressure in handwriting performance under the tracing mode and the free-hand mode of writing control. Experiment 1 investigated writing performance on six task configurations, viz., circles, unbroken straight lines and broken straight lines at 45°, 90° and 135° angles, and a straight line with movement reversal at halfway point, all in the tracing mode of control. Results showed no difference in writing time or writing pressure among the task configurations and were consistent with the complexity-independency hypothesis (Kao et al. 1982) proposed for the tracing mode of handwriting. Experiment 2 investigated writing performance in 26 Roman letters in the free-hand mode of writing control. Results showed both writing time and writing pressure to be a function of an increase of task complexity. A complexity-dependency hypothesis for the increase of writing pressure relative to task complexity in the free-hand mode of handwriting is suggested.

Progressive motion variability in handwriting tasks

Preliminary experiments on repeated handwriting and other motor tasks have disclosed a general phenomenon: intra-task pressure varies as a function of task progression, the variability enlarging progressively to a peak shortly before the task termination. This finding was referred to tentatively as the progressive motion variability (PMV). The present experiment was designed firstly to test this PMV hypothesis and secondly to determine the exact location of the peak pressure variability of the PMV curve. Twelve subjects traced 25 times each of 5 task configurations all with an identical task length. The configurations were circle, straight line, and lines with 45°, 90° and 135° downward angles. Results showed a significant difference in intra-task pressure variability for all the task configurations and for task segments within each configuration. Results also showed not only that pressure variability increased as a function of task progression, but also that the peak variability occurred uniformly at the 9th segment of the task progression for all configurations. These results confirmed PMV in the repeated performance of continuous writing tasks in the tracing mode of control. Implications of the PMV phenomenon and some theoretical interpretations of the PMV curve are discussed.

Temporal effect on tactile letter recognition by a tracing mode.

Two experiments examined the temporal effect on tactile letter recognition of sequentially tracing a stimulus in the order of making the necessary strokes. The effect of time interval between letter-strokes was examined in Exp. 1, with the three measures, recognition accuracy, latency, and readability. Accuracy of recognition did not differ by change in time intervals, but latency showed a downward trend, and readability showed an upward trend with an increase in the time interval. The effect of duration of exposure (number of pulses which activates each vibratory stimulator defining a letter) was examined in Exp. II with two measures, accuracy of recognition and latency. Both accuracy of recognition and latency reached optimum with 8 pulses per stimulator. The time interval between letter-strokes contributed strongly at the shorter exposure. The minimum was about 80 msec. for the interval between letter-strokes, and 4 pulses per stimulator considering the practical demands of fast exposure and easy identification.

Semiclassical bound-state methods in four-dimensional field theory: Trace identities, mode sums, and renormalization for scalar theories

Semiclassical and inverse scattering methods, previously restricted to two-dimensional models, are extended to four-dimensional scalar field theories. The necessary trace identities are derived, mode sums are carried out, and renormalization is explicitly demonstrated. The four-dimensional $\mathrm{O}(N)$ model is used to illustrate these techniques. A renormalized expression for bound-state energies of this model, parametrized by the scattering data of a three-dimensional Schr\"odinger equation, is obtained. This expression contains nontrivial quantum fluctuation effects, and corresponds to the leading-order term of a $\frac{1}{N}$ expansion. In this model, stable $n$-body bound states do not seem to appear, even though a two-body bound state has been found in a $\frac{1}{N}$ expansion of the Green's functions. Possible reasons for this failure to bind are discussed.

Comparison of models with theoretical examples

Our confidence that computer medals are correctly programmed is greatly enhanced when we are able to test them against special theoretical examples which exert them to the (usually unrealistic) limits of their capabilities. Agreement of models with experimental data and agreement with other models are important but totally separate matters where disagreements are often “explained away.” The most useful theoretical examples, and the rarest, are the few known exact solutions of the reduced wave equation for media without boundaries. Some of these yield exact solutions for bounded media by using a slight generalization of the classical method of images. For testing ray tracing programs for nonlayered media, some theoretical examples can be found in three recent papers invoking analytic function theory. For some special layered media, there are well-known analytic evaluations of the ray tracing and normal mode expressions. Finally, for a few special media, there is a new technique which directly generates caustic curves.

Off-Axis Excitation of the Coupled Cavity Spherical Laser Interferometer

The excitation of a concave optical resonator with one planar mirror by a laser source incident normally on the planar mirror is described. The problem is analyzed by describing the resonator fields by both ray tracing and normal mode analysis. The latter is more general, but it is shown that in the appropriate limit the two methods of analysis yield nearly identical solutions. Main emphasis in the analysis is placed on determination of the reflection coefficient, relative mode amplitudes, and field patterns. These are the parameters that are of interest to users of the scanning interferometer and the coupled cavity laser interferometer. The latter is commonly used to diagnose gaseous plasmas.