Abstract: The authors discuss aliasing errors in signature analysis registers for self-testing networks and review analytical results. The results show that when p, the probability that an error will occur at a network output, is close to 1/2, there is a bound of the aliasing error. The analysis uses a graph to represent the probability of transition, the Markov process, and z-transforms to analyze the behavior of the signature analysis register. For very small p(p?0) and very large p(p?1), the aliasing error solution for primitive polynomials is a series of terms (1-?)n in magnitude (where n is the number of random patterns being applied to the network or the length of the network output sequence). As compared with nonprimitive polynomials, whose solution is n(1-?)n or n2(1-?)n, in general primitive polynomials are much better with respect to aliasing. Simulation results are shown for aliasing errors for these polynomials, which give insight as to how aliasing occurs.

Abstract: We compared discrimination and detection in the parafovea for oblique, cathode-ray-tube-generated, square-wave gratings. There is a band of frequencies between roughly 10 and 20 cycles/deg wherein such gratings are detected only in an apparently aliased form. The existence of aliasing is consistent with the cone density and optical quality of the parafoveal visual system, but the spatial frequency at which the aliasing is observed is only about half of what is suggested by cone density. The reason for this result is unclear, but one provocative possibility is that the site of the aliasing is neural rather than receptoral.

Abstract: The collection of data suitable for impedance imaging is a well defined task. Once the number of electrodes is chosen, it is possible to specify the number of independent measurements which must be made. Having done so, a data collection system can be designed; preferably with the view to both maximising the speed of data collection and minimising the noise on the measurements. The former is desirable to eliminate aliasing when taking measurements on regions in which the conductivity varies with time, the latter to ensure maximum image quality. When designing such a system many practical problems become apparent. Some are a result of the electrical components used. In principle these can be overcome, although in practice they will always be important. Other problems arise from the nature of the measurements and the way in which they must be taken. These problems do not depend on how the hardware is implemented. They impose fundamental constraints on the quality of the measurements. The problems in the design of a data collection system are considered here. The design is analysed at the functional rather than electronic level, so the results are of general use. Factors considered include the number of measurements, speed of data collection, noise, bandwidth, isolation, common mode feedback, dynamic range, and quantisation.

Abstract: A two-part experiment was conducted to investigate the effects of aliasing artifacts and screen resolution on a simple visual recognition task. The results indicate that in many cases far less realism may be necessary in synthetic computer-generated imagery than is often assumed. The first part of the experiment was a subjective rating of image quality. The second part measured the relationship between image quality and task effectiveness: Subjects were asked to discriminate between images of two types of objects similar to objects used in experiments involving mental rotation. At higher resolutions, the elimination of aliasing artifacts did not significantly improve subjects' performances. At intermediate and low resolutions, comparable to what might be used for iconic menus, the reduction in aliasing artifacts improved performance. The subjective ratings indicate that for both high and low resolution the elimination of aliasing artifacts does not improve quality, whereas images rendered at intermediate resolutions are significantly degraded by aliasing artifacts to the extent that antialiasing improves the subjective rating. These results are interpreted in the context of an ongoing research program aimed at identifying the parameters of real-time human performance for graphics workstations.

Abstract: We study instability caused by aliasing error with repect to both the viscous Burgers' equation and the incompressible magnetohydrodynamic equations. “Soft” and “hard” breakdowns are predicted to occur in tokamak simulations. Nonlinear stability criteria can be formulated, but it seems preferable to use numerical schemes that are not prone to these breakdowns, notably EPIC.

Abstract: Two issues concerning alias-free, parallel, quadrature mirror filter (QMF) banks are addressed in this correspondence. First, a property concerning alias-free analysis/synthesis systems is established; second, a scheme is proposed, by which a synthesis bank can be modified in order to take care of aliasing errors caused by linear channel-distortion in a simple manner. Applications of the stated results are outlined.

Abstract: FORTRAN VERIFIER (FORTVER) is a tool to assist the development, testing and maintenance of large FORTRAN-77 programs. FORTVER will check module interfaces, and produce various documentation and cross-references. It will compute interprocedural, flow-insensitive sideeffects with complete static and dynamic aliasing in order to diagnose unused, unevaluated, unassigned, or otherwise illegally used variables. An improvement of Banning's algorithm for REF-parameter aliases is also introduced.

Abstract: Both proposals have one important disadvantage, i.e. the use of domain defined attributes in RFC987 and the insertion of new country codes (and also PRMDs) in the DFN specifications. If possible, these solutions should not be used when interconnecting X.40 and RFC822 mail networks. The mapping solutions of both proposals are very similar and with a little extension of the RFC987 aliasing mechanism the DFN solution can be seen as a special case of RFC87. This is especially true for the encoding of X.400 O/R Names in RFC822; for the mapping of RFC822 addresses to X.400 a “gateway addressing” seems to be necessary.

Abstract: . We have shown that it is not always possible to embed a real-valued discrete parameter Gaussian AR(1) model in a real-valued continuous parameter Gaussian AR(1). The problem with general ARMA models is also discussed.