Showing papers by "Technion – Israel Institute of Technology published in 1978"
TL;DR: The proposed concept of compressibility is shown to play a role analogous to that of entropy in classical information theory where one deals with probabilistic ensembles of sequences rather than with individual sequences.
Abstract: Compressibility of individual sequences by the class of generalized finite-state information-lossless encoders is investigated. These encoders can operate in a variable-rate mode as well as a fixed-rate one, and they allow for any finite-state scheme of variable-length-to-variable-length coding. For every individual infinite sequence x a quantity \rho(x) is defined, called the compressibility of x , which is shown to be the asymptotically attainable lower bound on the compression ratio that can be achieved for x by any finite-state encoder. This is demonstrated by means of a constructive coding theorem and its converse that, apart from their asymptotic significance, also provide useful performance criteria for finite and practical data-compression tasks. The proposed concept of compressibility is also shown to play a role analogous to that of entropy in classical information theory where one deals with probabilistic ensembles of sequences rather than with individual sequences. While the definition of \rho(x) allows a different machine for each different sequence to be compressed, the constructive coding theorem leads to a universal algorithm that is asymptotically optimal for all sequences.
3,753 citations
TL;DR: In this paper, the authors consider an estimation problem when only the k largest observations of a sample of size n are available, and present estimators for the location and scale parameters and for p-quantiles of F, where p is of the form 1 − c/n (c fixed).
Abstract: We consider an estimation problem when only the k largest observations of a sample of size n are available. It is assumed that the underlying distribution function F belongs to the domain of attraction of a known extreme-value distribution and that k remains fixed as n → ∞. We present estimators for the location and scale parameters and for p-quantiles of F, where p is of the form 1 — c/n (c fixed). These estimators are either asymptotically maximum likelihood or minimum variance.
591 citations
TL;DR: In this paper, the degradation of denatured globin in reticulocyte lysates is markedly stimulated by ATP, and the system is now resolved into two components, designated fractions I and II, in the order of their elution from DEAE-cellulose.
544 citations
403 citations
TL;DR: In this paper, tax evasion behavior of 15 subjects was observed in a game-simulation context, and large fines were found to be more effective deterrents than frequent audits, while the decision to underreport income was influenced by different factors than the magnitude of underreporting.
386 citations
TL;DR: In this article, a parametric study of large amplitude oscillatory propulsion, with special emphasis on the effect of chordwise flexibility of the fin, is presented, which increases the propulsive efficiency by up to 2% while causing small decreases in the overall thrust.
Abstract: The hydrodynamic forces due to the motion of a flexible foil in a large amplitude curved path in an inviscid incompressible flow are analysed. A parametric study of large amplitude oscillatory propulsion, with special emphasis on the effect of chordwise flexibility of the fin, is presented. This flexibility was found to increase the propulsive efficiency by up to 2% while causing small decreases in the overall thrust, compared with similar motion with rigid foils.
241 citations
TL;DR: The finite-state complexity of a sequence plays a role similar to that of entropy in classical information theory (which deals with probabilistic ensembles of sequences rather than an individual sequence).
Abstract: A quantity called the {\em finite-state} complexity is assigned to every infinite sequence of elements drawn from a finite sot. This quantity characterizes the largest compression ratio that can be achieved in accurate transmission of the sequence by any finite-state encoder (and decoder). Coding theorems and converses are derived for an individual sequence without any probabilistic characterization, and universal data compression algorithms are introduced that are asymptotically optimal for all sequences over a given alphabet. The finite-state complexity of a sequence plays a role similar to that of entropy in classical information theory (which deals with probabilistic ensembles of sequences rather than an individual sequence). For a probabilistic source, the expectation of the finite state complexity of its sequences is equal to the source's entropy. The finite state complexity is of particular interest when the source statistics are unspecified.
202 citations
TL;DR: In this article, resistivity and dielectric constant of polyethylene/carbon black compounds were measured from room temperature to 140°C, and the PTC/NTC phenomenon was observed, whose intensity depends on the type of carbon black, its concentration and other parameters.
Abstract: Resistivity and dielectric constant of polyethylene/carbon black compounds were measured from room temperature to 140°C. Within the polyethylene melting region a PTC/NTC (positive followed by negative temperature coefficients) phenomenon is observed, whose intensity depends on the type of carbon black, its concentration and other parameters. Reproducibility of the PTC phenomenon in polyethylene compounds containing a single type of carbon black is rather low. However, by using mixtures of carbon blacks differing appreciably in their particle size, remarkable reproducibility improvements can be achieved. Several other aspects are also discussed in the present paper covering current-voltage relationships in these materials, comparison of PTC curves with DSC thermograms upon heating and cooling, and dielectric constant-temperature relations. The carbon black concentration giving the optimum PTC intensity can be predicted approximately from room temperature data.
183 citations
TL;DR: The findings suggest that the evoked response to noxious heat reflects not a mere transduction of the physical parameters of the stimulus, but rather a complex interpretative action at the cerebral level.
Abstract: The relationships between different parameters of the evoked cerebral response to noxious thermal stimulation, stimulus intensity, and subjective pain were investigated in seven normal human volunteers. The evoked response was characterized by late events: a small negative peak at 164–180 ms, followed by a high amplitude positive peak at 372–391 ms. The only correlation found in this study was between the amplitude of the positive component and the qualitative and quantitative aspects of the verbal report of pain. This was manifested by a linear trend of association: an increase in the evoked response amplitude was accompanied by an increase in the magnitude of the subjective sensation. The findings suggest that the evoked response to noxious heat reflects not a mere transduction of the physical parameters of the stimulus, but rather a complex interpretative action at the cerebral level.
179 citations
TL;DR: In this paper, a note on the inverse problem for nonnegative matrices is given for linear and multilinear matrices, where the inverse is a nonnegative matrix inverse problem.
Abstract: (1978). A note on an inverse problem for nonnegative matrices. Linear and Multilinear Algebra: Vol. 6, No. 1, pp. 83-90.
174 citations
TL;DR: This inexpensive, easy to perform, and highly informative technique can be of great value in the routine clinical work-up and in research studies and the average sperm speed may become a new index in any routine semen analysis.
TL;DR: In this article, the authors determined the lead-lag natural frequencies and mode shapes of a radial beam mounted on a rotating disc at a 90° setting angle by means of the finite element technique, a high precision beam element based on a fifth degree polynomial being used as displacement function, with deflection and slope at the ends as common nodal degrees of freedom.
TL;DR: The morphology of the VEP changed for sets above short-terms span, and latency changes in P270 and P350 no longer predicted RT changes, since subject's strategy was not controlled for supra-span sets, no definite conclusions were offered.
TL;DR: In this article, the authors derived closed equations for the velocity correlation tensor and for the mean-squared displacement of a particle suspended in a stationary homogeneous turbulent flow, with an arbitrary linear law of fluid-particle interaction.
Abstract: The closed equations for the velocity correlation tensor and for the mean-squared displacement of a particle suspended in a stationary homogeneous turbulent flow, with an arbitrary linear law of fluid-particle interaction, are obtained using two assumptions suggested previously for the problem of turbulent self-diffusion: the ‘independence approximation’ and the Gaussian property of the functional distribution of particle velocities. The numerical solution of the derived equations is given for an isotropic system with a model turbulence spectrum. The following characteristics of the particle motion are obtained: ( a ) the mean kinetic energy, ( b ) diffusivity, ( c ) rate of energy dissipation, ( d ) velocity correlation function, and ( e ) the correlation function of the relative fluid-particle velocity. The impact of various spectral modes on the characteristics of the particle motion is discussed.
TL;DR: Right ear superiority was found for two groups of 24 subjects on a dichotic listening test of melodies each differing only in rhythm, and for one test the reverse was true: the left hemisphere was superior to the right for melody recognition based on a rhythm cue.
TL;DR: A simple hydrodynamic model which relates the slip-speed and lift-off speed of fish and benthic organisms in flowing water to the physical forces acting on the fish has been verified experimentally using freshly killed fish and a rigid model.
Abstract: Plaice resting on the bottom of a flume respond to the current with a clearly defined pattern of behaviour. A simple hydrodynamic model which relates the slip-speed ( U s ) and lift-off speed ( U L ) to the physical forces acting on the fish has been verified experimentally using freshly killed fish and a rigid model. With an asymmetric semi-ellipsoid shape and a fineness ratio of 14 the plaice appears to be morphologically adapted to have minimum drag when heading into the current. As a result of this streamlined shape the lift force experienced by the fish is 10-20 times greater than the drag force, and the rheotactic behaviour therefore appears to be principally adapted to counteract hydrodynamic lift. Values of U s and U L , above which live fish must expend energy against the current, are exceeded for much of each tidal cycle in the southern North Sea. The model is of general application to benthic organisms in flowing water for Reynolds numbers between 10 4 and 10 6 ; outside these limits some modification of the constants is required.
TL;DR: It is shown that on the average log logN file accesses are required to retrieve a key, assuming that the N keys are uniformly distributed, and the number of extra accesses is estimated and shown to be very low.
Abstract: Interpolation search is a method of retrieving a desired record by key in an ordered file by using the value of the key and the statistical distribution of the keys. It is shown that on the average log logN file accesses are required to retrieve a key, assuming that the N keys are uniformly distributed. The number of extra accesses is also estimated and shown to be very low. The same holds if the cumulative distribution function of the keys is known. Computational experiments confirm these results.
TL;DR: In this paper, the authors present an experimental study of the turbulent structure on the centre line of a two-dimensional impinging jet, where the mean velocity, turbulent stresses, triple velocity products and temporal derivatives were measured and the energy balances for the three fluctuating components were calculated.
Abstract: This paper presents an experimental study of the turbulent structure on the centre-line of a two-dimensional impinging jet. The mean velocity, turbulent stresses, triple velocity products and temporal derivatives were measured and the energy balances for the three fluctuating components were calculated. The results indicate a selective stretching of vortices in the direction in which the streamlines spread near the wall, causing anisotropy in this region. The distribution of energy among various frequencies was found from spectral measurements. These measurements revealed the existence of a neutral frequency above which the energy was attenuated by viscous dissipation and below which it was augmented by a vortex-stretching mechanism.
TL;DR: An efficient algorithm for finding all perfect matchmgs is presented and it requires O(e) time per matching and a total of O( e) space to calculate the permanent of a matrix.
Abstract: Certam apphcatlons require finding a perfect matching in a bipartite graph that satisfies some additional properties For one such type of restncUon the problem is proven to be NP-complete. If for a single subset of edges no more than r edges may be included m the matching then an O(ne) algorithm is given An efficient algorithm for finding all perfect matchmgs is presented It requires O(e) time per matching and a total of O(e) space This algorithm may be used to calculate the permanent of a matrix Finally, the algorithm ts generahzed to find all maximum matchmgs
TL;DR: In vitro studies demonstrated that (-)deprenyl in comparison to d, l-tranylcypromine, clorgyline and harmaline is by far the most potent inhibitor of human brain MAO, and long-term treatment with more than 1 mg/10 kg body weight could result in an accumulation of (-)DeprenylIn the brain.
Abstract: It has been shown that 5 or 10 mg (-)deprenyl after i.v. application inhibited platelet MAO within 30 min. This effect correlated with the improvement of parkinsonian patients disability. Platelet MAO is purely of type B, thus resembling the human brain enzyme, which is 80% of type B. In other organs of the human MAO-A is of higher activity, thus it can oxidatively deaminate 5-HT, noradrenaline and tyramine in the periphery. The rather low peripheral side effects of (-)deprenyl can be explained by this fact. In vitro studies demonstrated that (-)deprenyl in comparison to d, l-tranylcypromine, clorgyline and harmaline is by far the most potent inhibitor of human brain MAO. Post-mortem studies in different human brain areas showed that there are differences in the behaviour of (-)deprenyl (10 mg) between short- and long-term treatment. Both show sufficient inhibition of DA-sensitive MAO (85–90%). However, when 5-HT is used as a substrate short-term treatment inhibits by about 40–50% whereas long-term treatment inhibits by about 65% which is higher than that mentioned before but not sufficient to increase brain 5-HT or decrease 5-HIAA. Therefore, long-term treatment with more than 1 mg/10 kg body weight could result in an accumulation of (-)deprenyl in the brain. Evidence for this derives from one parkinsonian patient, who was treated with 100 mg (-)deprenyl in which case both forms of the enzyme were inhibited sufficiently to increase DA and 5-HT in several brain regions.
TL;DR: Easy performance, rapid sperm counts, and improvement of motility estimation make this chamber a useful tool where sperm analysis is carried out.
TL;DR: In this paper, a discrete dynamical system whose evolution is governed by rules similar to those of Conway's game of Life is studied, where a stochastic element is also included.
Abstract: We study a discrete dynamical system whose evolution is governed by rules similar to those of Conway's game of Life but also include a stochastic element (parametrized by a “temperature”). Statistical properties that are examined are density as a function of temperature and entropy (suitably defined). A phase transition and a certain “thermodynamic” constant of the motion are observed.
TL;DR: In this article, a Poisson-Boltzmann equation with hydration forces acting on the ions in an interface is derived with the main differences from the Gouy-Chapman theory are the following: lowering of the surface ion concentrations; breaking of the linear connection between the surface charge and the surface electrical field; bending of the differential capacity curves of the double layer; separating in adsorptions of the ion species of the univalent polyelectrolyte.
TL;DR: In this article, the problem of non-null ranking has been studied and a measure of concordance has been proposed to measure the degree to which judges act concordantly or homogeneously with respect to a particular ranking which is not assumed known beforehand.
Abstract: CONSIDER a number n of judges, each of whom ranks the same set of k objects according to some particular criterion. Assume that each judge ranks (stochastically) independently of the other judges so that we regard the situation as that of n rankings (Daniels, 1950; Kendall, 1970) or of n related samples (Conover, 1971, p. 246). We wish to say something about whether and to what degree the judges act concordantly (or homogeneously) with respect to a particular ranking which is not assumed known beforehand. More particularly we wish to estimate this underlying ranking and also consider a model for the proposed measure of concordance. In so doing we address ourselves to the problem of non-null modelling referred to in Kendall (1970, p. V). To place the suggested model in its proper setting it is appropriate to review briefly the relevant literature on modelling non-null distributions for rankings. These models may be, broadly speaking, divided into three classes: (I) parametric; (II) paired comparison; and (III) sampling. The parametric approach may be further subdivided into the categories: (Ia) multivariate; and (Ib) independent deviations. They may be described as follows:
TL;DR: It is shown that regardless of the ω-recognition model considered, non-deterministic τ-Turing acceptors are strictly more powerful than their deterministic counterparts.
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TL;DR: It is shown that finding maximum two-commodity flow m a dwected graph is much more dffficuh, and the problem of finding feasible flow m an undirected graph with lower and upper bounds on the edges is shown to be NP-complete even for a single commodity.
Abstract: An algorithm is given to fmd maxtmum two-commodity flow m an undirected graph The algorithm is an improvement on Hu's two-commodity flow algorithm using the methods of Dmlc's single-commodity flow algorithm Karzanov's Improvement of Dmlc's algorithm can be applied to yield an O(I V ) 3) algorithm. It is shown that finding maximum two-commodity flow m a dwected graph is much more dffficuh, in fact it Is as difficult as hnear programming FmaUy, the problem of finding feasible flow m an undirected graph with lower and upper bounds on the edges is shown to be NP-complete even for a single commodity