Hashing technique based on SHA-3 using chaotic maps1

New hashing technique based on SHA-3 (Secure Hash Algorithm-3) is introduced. Chaotic maps are used in this technique to enhance performance without losing security. Introduced algorithm was tested for resistance against collisions, statistical analysis of output sequences was performed, hashing performance was evaluated. The testing showed a low collision probability. The testing corresponds the standards of National Institute of Standards and Technology and showed that output sequences are close to random. Performance testing showed 60 % enhancement in comparison with plain SHA-3.

Validity of the RSA-RANDOM Test for Young Soccer Players

The present study aimed to examine the reliability, usefulness, responsiveness, age-related differences and construct validity of a novel decision-making RSA test (RSA-RANDOM test) in young soccer players. Twenty-five young male soccer players performed the RSA-RANDOM test on 2 occasions separated by 5–7 days to assess test-retest reliability and determine a priori usefulness. Furthermore, the same players executed the RSA-RANDOM test 4 times throughout the season to analyse responsiveness. Forty-five players (U–13 to U–17) were evaluated in such test to examine age-related differences. Finally, 9 players were used to determine the construct validity of the test. Reliability scores showed a high intraclass correlation coefficient (ICC=0.88 to 0.90) and low coefficient of variation (CV=1.0–1.2%). The responsiveness of the RSA-RANDOM test was good, as the typical short- (1.2–1.9%), mid- (1.4–2.4%) and long-term (2.3–3.2%) changes in RSA-RANDOM performance were higher than the CV. Age-related differences analysis showed better RSA-RANDOM performance as age increased in young soccer players. Low (r=−0.50) to moderate (r=−0.75) relationships were found between the RSA-RANDOM test variables (RSA best and mean times) with high-intensity and total distance covered, respectively. A novel decision-making RSA test (RSA-RANDOM) has shown to be reliable and valid in young soccer players.

The Effect of Orientation on Alignment Performance

It has been found that the 3-Gabor alignment task is performed equally well whether the orientations of the patches are collinear, parallel, or orthogonal. But does the orientation of the individual micropatterns have any effect on performance? The ability (threshold) of subjects to determine whether the middle Gabor patch of a 3-patch display was displaced to the right or the left was measured in a variety of conditions. When the orientation of the Gabors was random, performance was poorer than in the three standard conditions mentioned above. If the outer Gabors had orientations of 45° and 135° and the centre patch was vertical, then thresholds were even higher, and the point of subjective equality for the task was displaced from centroid alignment towards a position where the patches form a head-to-tail contour. However, phase randomisation did not affect performance appreciably compared to the standard conditions, and, if Gaussian patches with normally distributed standard deviations were employed, the uncertainty on the Gaussian patch size did not impoverish the ability of observers to do the task. The implication of these results is that orientational factors can affect performance, and that the visual system attempts to form contours out of plausibly located oriented segments, thus masking centroid cues. In the absence of orientational disruption it does indeed appear that centroid-like cues are used, as the randomisation of bar positions or Gaussian blob size did not degrade thresholds. The universal result that orientation does not improve performance indicates that its role in this task is that of a mask rather than a cue.

Participant structure and the on-line production of discourse context

This paper presents the micro-analysis of one interrupted and unfinished Dutch 'sentence' that was heard in a popular Dutch Talk Show called 'Sonja op Zaterdag'.1 It contains a self-correction that is produced as a change in 'footing' (Goffman 1979). The issue is raised whether the abandonment of the sentence-under-construction should be considered a random, 'performance' type phenomenon or whether it can be accounted for systematically in terms of discourse-level constraints on the interruptability of sentences (cf. Schegloff 1979). I will argue that the latter seems to be the case. Analyses of the data and hypothetical alternatives to it reveal that observed differences can be articulated in a dynamic discourse model in which utterances may themselves produce contextual updates (Polanyi and Scha 1983; Polanyi 1988; applied to classroom data by van Dam van Isselt 1993). It is suggested that the model should be extended to acknowledge 'defective' sentences.