Showing papers by "Technion – Israel Institute of Technology published in 1979"
TL;DR: In this article, a class of dynamical systems in the presence of uncertainty is formulated by contingent differential equations, and the uncertainty is deterministic; the only assumption is that its value belongs to a known compact set.
Abstract: A class of dynamical systems in the presence of uncertainty is formulated by contingent differential equations. Asymptotic stability (in the sense of Lyapunov) is then developed via generalized dynamical systems (GDS's). The uncertainty is deterministic; the only assumption is that its value belongs to a known compact set. Application to variable structure and model reference control systems are discussed.
594 citations
TL;DR: It is shown that theNonuniformity in the angular distribution of the fibers accounts for the observed anisotropic behavior of the tissue, and that the nonuniformities in the geometrical structure of the fiber accounts forThe nonlinear stress-strain relations.
383 citations
TL;DR: The algorithm can be employed in message as well as circuit switching networks, uses distributed computation, provides routing tables that are loop-free for each destination at all times, adapts to changes in network flows, and is completely failsafe.
Abstract: An algorithm for constructing and adaptively maintaining routing tables in communication networks is presented. The algorithm can be employed in message as well as circuit switching networks, uses distributed computation, provides routing tables that are loop-free for each destination at all times, adapts to changes in network flows, and is completely failsafe. The latter means that after arbitrary failures and additions, the network recovers in finite time in the sense of providing routing paths between all physically connected nodes. For each destination, the routes are independently updated by an update cycle triggered by the destination.
227 citations
TL;DR: Utilizing arterial travel time data from the Chicago area, both a regression and a statistical model are show to serve as efficient techniques in predicting reliability.
Abstract: This study is concerned with travel time and operational reliability on arterial routes. Reliability is viewed in terms of the consistency of operation of the route under investigation and defined in terms of the inverse of the standard deviation of the travel time distribution. Under certain assumptions, travel time behavior on an arterial route is seen to closely follow a gamma distribution; the reliability measure can be derived accordingly. Utilizing arterial travel time data from the Chicago area, both a regression and a statistical model are show to serve as efficient techniques in predicting reliability. The prediction models are evaluated.
175 citations
TL;DR: The theoretical background of experimentally observed polymorphic transformations occurring during comminution processes (e.g. dry grinding of minerals) is discussed in this paper, where both the specific surface energy and volumetric elastic strain energy terms in the overall Gibbs free energy equation for the system in question play a major role in these transformations.
173 citations
TL;DR: It is shown that, by incorporating pitch frequency information into a frequency-scaling process based on STFA, it is possible, to a good approximation, to perform this operation in the time domain with very few arithmetic operations.
Abstract: Frequency scaling of speech signals by methods based on short-time Fourier analysis (STFA), analytic rooting, and harmonic compression using a bank of filters, is a complex operation which requires a large amount of computation in a digital implementation. It is shown in this paper that, by incorporating pitch frequency information into a frequency-scaling process based on STFA, it is possible, to a good approximation, to perform this operation in the time domain with very few arithmetic operations (one multiplication and two additions per output sample, in most applications). The derivation of the time-domain harmonic scaling (TDHS) algorithms, selection of parameters, and, in particular, the determination of an appropriate weighting function used in the algorithms, as well as several potential applications, are detailed in the paper. Two proposed applications are discussed in greater detail. These are 1) a vocoder system which incorporates waveform coding of the frequency divided signal (by a factor of up to 3), and 2) a computer-based isolated-word recognition system in which all input utterances are compressed to the same duration at the preprocessing phase effecting an overall computation reduction by a factor of up to 3. Computer simulation results which demonstrate the TDHS algorithms' performance are included.
171 citations
TL;DR: In this paper, it was shown that if a Borel function f is such that T transforms a Sobolev space W1, p(Ω) (1 ⩽ p < ∞) into itself, then T is necessarily continuous.
157 citations
TL;DR: Results contradict the internal inhibition hypothesis, which proposes that hippocampal damage affects the motivation to perform spontaneousAlternation, and indicate that the spontaneous alternation deficit may be due to memory loss.
133 citations
TL;DR: A method for the determination of total Kjeldahl nitrogen in soil and water samples is presented in this article, where the sample is digested with a potassium persulphate solution in an autoclave and then reduced to ammonium with Devarda alloy and ammonium determined colorimetrically.
124 citations
TL;DR: Patients who had combat neuroses resulting from the 1973 Yom Kippur War and complained of sleep disturbances showed significantly longer sleep latencies, lower sleep efficiency indices, lower percentage of REM sleep, and longer REM latencies.
Abstract: Eleven patients who had combat neuroses resulting from the 1973 Yom Kippur War and complained of sleep disturbances were studied in a sleep laboratory. Sleep-onset insomniacs, dream-interruption insomniacs, and pseudoinsomniacs were differentiated on the basis of electrophysiologic recordings. Compared with normal controls who actively participated in the Yom Kippur War, patients showed significantly longer sleep latencies, lower sleep efficiency indices, lower percentage of REM sleep, and longer REM latencies.
123 citations
TL;DR: In this paper, a vibration based diagnostic method aimed at detecting localized defects developing in roller/ball bearings is described, which is shown to be applicable for cases where spectral analysis fails to give results.
Abstract: Described is a vibration based diagnostic method aimed at detecting localized defects developing in roller/ball bearings. The signature is decomposed into generalized periodic functions and a search strategy for the various components developed and implemented. The method is shown to be applicable for cases where spectral analysis fails to give results.
01 Jan 1979
TL;DR: In this paper, the two basic approaches to the study of nonnegative matrices are geometrical and combinatorial, using the elementwise structure in which the zero-nonzero pattern plays an important role.
Abstract: Publisher Summary
This chapter discusses square nonnegative matrices, that is, square matrices all of whose elements are nonnegative. The matrices A that satisfy A > 0 are called positive matrices. The two basic approaches to the study of nonnegative matrices are geometrical and combinatorial. The chapter describes the combinatorial matrices, using the elementwise structure in which the zero–nonzero pattern plays an important role. It also discusses the irreducible matrices and the reducible case. An irreducible matrix is primitive if its trace is positive. The order of cyclicity of a matrix can be computed by inspection of its directed graph. If there are n possible states of a certain process and the probability of the process moving from state si to state sj is time independent, such a process is called a finite homogeneous Markov chain. The maximal eigenvalue of a stochastic matrix is one. A nonnegative matrix T is stochastic if and only if e is an eigenvector of T corresponding to the eigenvalue one.
TL;DR: In this article, the authors examined the effect of type and amount of organic substrate on denitrification efficiency and found that when the organic matter was expressed as BOD, a critical ratio of (mg BOD/mg ΣNO x -N) = 2.3 ensured 100% denitification.
TL;DR: In this paper, a flexible mirror constructed from plates of glass and lead zirconium titanate (PZT) piezoelectric ceramic glued together is described, which is activated by a series of electrodes on the reverse side.
Abstract: We describe a flexible mirror constructed from plates of glass and lead zirconium titanate (PZT) piezoelectric ceramic glued together. It is activated by a series of electrodes on the reverse side. An equation of state is derived, giving the surface profile as a function of the electrode voltages, and the experimental behavior of the mirror is illustrated.
TL;DR: This paper focuses on the design and analysis of a language for the expression of nondeterministic, concurrent, and communicating programs, and one recent attempt to design such a language was done by Hoare.
TL;DR: The "topology" of a protocol is defined, and protocols that are intended to work in a variety of configurations, as well as configurations which may change in time (i.e. "evolving topologies").
Abstract: Complex protocols are used to coordinate remote activities in computer networks. To insure proper operation, formal techniques of protocol definition and validation have been proposed, and developed to the point that they can be applied to actual protocols. However, much work remains to be done in order to cope with protocols of ever-increasing complexity; in particular, those coordinating the activities of many interacting entities. The characteristics that determine the applicability of the different specification and validation techniques to a protocol will be discussed. We will define the "topology" of a protocol, and treat also protocols that are intended to work in a variety of configurations, as well as configurations which may change in time (i.e. "evolving topologies"). Finally, based on this new general point of view, a short survey of specification and validation techniques will be presented, and the extensions needed to handle complex protocol characteristics will be discussed.
TL;DR: In this paper, a typical Israeli water heating system in thermosyphonic flow was tested and the results show relatively linear temperature distributions both along the collectors and in the storage tank when no water consumption was allowed.
15 Oct 1979
TL;DR: In this article, a simple model for computing the stability ratio of primary minimum coagulation (PMC) and SMC was proposed, which is based on the kinetic theory and enables us to compute the stability ratios of combined PMC and SMC, a possibility excluded by the assumptions underlying previous models.
Abstract: A simple model for computing the stability ratio of primary minimum coagulation (PMC) and secondary minimum coagulation (SMC) is suggested. It is based on the kinetic theory and enables us to compute the stability ratio of combined PMC and SMC, a possibility excluded by the assumptions underlying previous models. The model simulates well, for the first time, experimental data concerning particle size dependence of the stability ratio. This agreement supports the suggestion that the weak dependence of the stability ratio on particle size and possibly on other parameters is due to the combination of the two modes of coagulation.
TL;DR: In this paper, a combined analytical and experimental study was performed on the ballistic resistance of layered targets, in particular of flat, relatively thin beams with clamped ends in spaced and laminated (i.e. in contact without bonding) conditions.
TL;DR: Evidence is presented which suggests that post-translational modifications of proteins are the main cause of enzyme inactivation in old animals.
TL;DR: The intensity of binding of each lectin to the pigment epithelium plasma membrane was similar to its binding to the rod outer segment plasma membrane, and no differences were observed in the binding of ferritin-lectin complexes to rod outer segments from dark or light adapted frogs.
01 Jan 1979
TL;DR: In this article, the authors discuss the algebraic theory of semigroups of nonnegative matrices, and the most important applications of the material in the chapter involve the solvability of certain nonnegative matrix equations arising in the areas of mathematical economics and mathematical programming.
Abstract: This chapter discusses the semigroups of nonnegative matrices. The matrix multiplication is associative, and the product of two non-negative matrices is again a nonnegative matrix. The most important applications of the material in the chapter involve the solvability of certain nonnegative matrix equations arising in the areas of mathematical economics and mathematical programming. A subgroup G of a semigroup T is called a maximal subgroup of T if it is not properly contained in any other subgroup of T . This chapter discusses the algebraic theory of semigroups of nonnegative matrices. Idempotent elements play a fundamental role in algebraic semigroup theory. Every matrix in the semigroup N n of nonnegative matrices is not regular. The tool to be used to characterize Green's relations for regular elements in N n would be that of rank. However, this tool is more of a vector space notion and is too sophiscated to characterize Green's relations on the entire semigroup N n .
TL;DR: In this article, Elastic-viscoplastic constitutive equations based on two internal state variables are utilized to determine material response for uniaxial cyclic loading conditions, such as softening upon stress reversal, cyclic hardening or softening, tendency towards a stable limit cycle and cyclic relaxation.
Abstract: : Elastic-viscoplastic constitutive equations based on two internal state variables are utilized to determine material response for uniaxial cyclic loading conditions. These equations are capable of representing the principal features of cyclic loading behavior including softening upon stress reversal, cyclic hardening or softening, tendency towards a stable limit cycle, cyclic relaxation, and cyclic creep. Calculations were performed for various stress and strain controlled conditions using material constants intended to represent commercially pure titanium and aluminum and OFHC copper. Capabilities and limitations of the analytical formulations are discussed in relation to computed results and corresponding test data. (Author)
TL;DR: This work is intended to convey to the reader the phase of transition that public cryptology is in at the present time and the evolving state of the art.
Abstract: This work is intended to convey to the reader the phase of transition that public cryptology is in at the present time and the evolving state of the art. The transition is multifaceted: In scope of relevancy it has evolved from a government monopoly dealing with military and diplomatic communications to a major concern of business in general, the banking industry in particular, and, more recently, the public at large. Its technology has expanded from paper-andpencil and various mechanical devices to large, high-speed, electronic computers. Its security emphasis has changed from statistical uncertainty to computational complexity. And last, but not least, in concept it has developed from conventional, private-key schemes to public-key cryptosystems providing instant privacy and twoway authentication. This latest transition also reflects the rapidly evolving state of the \"art\" of cryptology. Since its recent adoption by the
TL;DR: In this paper, it was proved that balanced 3-designs B3[k, λ, v] exist for k = 5, k λ = 30 and every v ⩾ 5.
TL;DR: The need for periodic bone scintigraphy, even when the clinical state does not seem to warrant it, is discussed, and the association between bone metastases and pain is discussed.
Abstract: One hundred ninety patients with breast cancer were prospectively evaluated for bone pain and had technetium Tc 99m-methylene diphosphonate bone scintigraphy for bone metastases. Of the 66 patients showing evidence for bone metastases, 21 (32%) did not have bone pain. There were 155 sites of skeletal metastases, but pain was found only in 50 sites. The age of the patient or involvement of weight-bearing bones did not seem to affect the association between bone metastases and pain. We discuss the need for periodic bone scintigraphy, even when the clinical state does not seem to warrant it. ( JAMA 242:1747-1748, 1979)
TL;DR: By using the “savings method” proposed by Clarke and Wright, and extended by Gaskell, each one of the above problems is defined as a series of assignment problems, and it is possible to obtain the optimal solution in a finite number of steps.
TL;DR: In this paper, the effect of inertia, diffusion and interception on dust deposition was analyzed and a single solution for the filtration efficiency accounting for all these effects was proposed. But the results of the analysis were limited to the case of an electrically neutral filter bed.
TL;DR: In this paper, conditions under which a the sum of forecasts of sales in market segments is preferred to a forecast of the whole market and b the forecast of an individual market segment is preferable to the forecast obtained through proration of a forecast for the entire market were determined.
Abstract: Conditions are determined under which a the sum of forecasts of sales in market segments is preferred to a forecast of the whole market and b a forecast of an individual market segment is preferred to a forecast obtained through proration of a forecast of the whole market. The comparisons in a and b are also applied to the problem of forecasting for several time periods into the future.