Showing papers by "University of Potsdam published in 1995"
TL;DR: Some complexity measures that are based on symbolic dynamics as well as a new measure, the renormalized entropy, detect some abnormalities in the HRV of several patients who have been classified in the low risk group by traditional methods.
Abstract: In the modern industrialized countries every year several hundred thousands of people die due to sudden cardiac death. The individual risk for this sudden cardiac death cannot be defined precisely by common available, noninvasive diagnostic tools like Holter monitoring, highly amplified ECG and traditional linear analysis of heart rate variability (HRV). Therefore, we apply some rather unconventional methods of nonlinear dynamics to analyze the HRV. Especially, some complexity measures that are based on symbolic dynamics as well as a new measure, the renormalized entropy, detect some abnormalities in the HRV of several patients who have been classified in the low risk group by traditional methods. A combination of these complexity measures with the parameters in the frequency domain seems to be a promising way to get a more precise definition of the individual risk. These findings have to be validated by a representative number of patients. (c) 1995 American Institute of Physics.
445 citations
TL;DR: A new scheme for built-in test that uses multiple-polynomial linear feedback shift registers (MP-LFSR's) and an implicit polynomial identification reduces the number of extra bits per seed to one bit is presented.
Abstract: We propose a new scheme for built-in test (BIT) that uses multiple-polynomial linear feedback shift registers (MP-LFSR's). The same MP-LFSR that generates random patterns to cover easy to test faults is loaded with seeds to generate deterministic vectors for difficult to test faults. The seeds are obtained by solving systems of linear equations involving the seed variables for the positions where the test cubes have specified values. We demonstrate that MP-LFSR's produce sequences with significantly reduced probability of linear dependence compared to single polynomial LFSR's. We present a general method to determine the probability of encoding as a function of the number of specified bits in the test cube, the length of the LFSR and the number of polynomials. Theoretical analysis and experiments show that the probability of encoding a test cube with s specified bits in an s-stage LFSR with 16 polynomials is 1-10/sup -6/. We then present the new BIT scheme that allows for an efficient encoding of the entire test set. Here the seeds are grouped according to the polynomial they use and an implicit polynomial identification reduces the number of extra bits per seed to one bit. The paper also shows methods of processing the entire test set consisting of test cubes with varied number of specified bits. Experimental results show the tradeoffs between test data storage and test application time while maintaining complete fault coverage. >
439 citations
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TL;DR: Modularity and structural determinism are stressed in the grammar and the parser as well as in the structure of the parser itself.
Abstract: Acknowledgments 1. Introduction 2. Properties of the grammar 3. Analyses of previous work 4. Properties of the parser 5. Modularity and structural determinism 6. Conclusion Reference Index.
180 citations
TL;DR: It is shown that phase sensitivity appears if there is a nonzero probability for positive local Lyapunov exponents to occur and a phase sensitivity exponent is calculated, that measures the sensitivity with respect to changes of the phase of the external force.
Abstract: Strange nonchaotic attractors typically appear in quasiperiodically driven nonlinear systems. Two methods of their characterization are proposed. The first one is based on the bifurcation analysis of the systems, resulting from periodic approximations of the quasiperiodic forcing. Second, we propose to characterize their strangeness by calculating a phase sensitivity exponent, that measures the sensitivity with respect to changes of the phase of the external force. It is shown that phase sensitivity appears if there is a nonzero probability for positive local Lyapunov exponents to occur.
163 citations
01 Dec 1995
TL;DR: Experiments show that the area required for synthesizing a BIST scheme that encodes these patterns is significantly less than the area needed for storing a compact test set.
Abstract: Recently a deterministic built-in self-test scheme has been presented based on reseeding of multiple-polynomial linear feedback shift registers. This scheme encodes deterministic test sets at distinctly lower costs than previously known approaches. In this paper it is shown how this scheme can be supported during test pattern generation. The presented ATPG algorithm generates test sets which can be encoded very efficiently. Experiments show that the area required for synthesizing a BIST scheme that encodes these patterns is significantly less than the area needed for storing a compact test set. Furthermore, it is demonstrated that the proposed approach of combining ATPG and BIST synthesis leads to a considerably reduced hardware overhead compared to encoding a conventionally generated test set.
156 citations
TL;DR: In this article, a C-14 varve chronology of lake Holzmaar (Germany) is presented, which reaches back to ca. 13.8 ka cal. BP and compares favorably with the results from Soppensee (Switzerland).
130 citations
TL;DR: In this article, it was shown that in the quasiperiodically forced circle map strange non-chaotic attractors can appear for non-linearities far from the border of chaos.
105 citations
TL;DR: A cDNA encoding a receptor for the oxytocin‐related peptide isotocin has been identified by screening a lambda gt11 library constructed from poly(A)+ RNA of the hypothalamic region of the teleost Catostomus commersoni indicating that this receptor may mediate a variety of physiological functions.
75 citations
TL;DR: In this article, a bienzyme electrode based on the amplification of a signal has been developed which allows the determination of picoto nanomolar concentrations of p-aminophenol.
71 citations
TL;DR: The occurrence of regimes with singular continuous (fractal) Fourier spectra in autonomous dissipative dynamical systems, including an ODE system at the accumulation points of bifurcation sequences associated to the creation of complicated homoclinic orbits is demonstrated.
Abstract: We demonstrate the occurrence of regimes with singular continuous (fractal) Fourier spectra in autonomous dissipative dynamical systems. The particular example is an ordinary-differential-equation system at the accumulation points of bifurcation sequences associated with the creation of complicated homoclinic orbits. Two different mechanisms responsible for the appearance of such spectra are proposed. In the first case, when the geometry of the attractor is symbolically represented by the Thue-Morse sequence, both the continuous-time process and its discrete Poincar\'e map have singular power spectra. The other mechanism is due to the logarithmic divergence of the first return times near the saddle point; here the Poincar\'e map possesses the discrete spectrum, while the continuous-time process displays the singular one. A method is presented for computing the multifractal characteristics of the singular continuous spectra with the help of the usual Fourier analysis technique.
69 citations
01 Jan 1995
TL;DR: A structural approach is used, based on indirect implications derived by using Recursive Learning, to formulate a hybrid approach where this structural method is used to reduce the complexity of a subsequent functional method based on OBDDs.
Abstract: This paper presents a new methodology for formal logic verification for combinational circuits. Specifically, a structural approach is used, based on indirect implications derived by using Recursive Learning. This is extended to formulate a hybrid approach where this structural method is used to reduce the complexity of a subsequent functional method based on OBDDs. It is demonstrated how OBDD-based verification can take great advantage of structural preprocessing in a synthesis environment. The experimental results show the effective compromise achieved between memory-efficient structural methods and functional methods. One more advantage of these methods lies in the fact that resources that go into logic synthesis can effectively be reused for verification purposes.
TL;DR: In this article, a minerogenic layer was found in early postglacial organic sediments from five maar lakes (West Eifel Volcanic Field, Germany) with a mean radiocarbon age of 9 560 years BP.
Abstract: A minerogeniclayer occurs in early postglacial organic sediments from five maar lakes (West Eifel Volcanic Field, Germany). The mineralogy and stratigraphic position of this tephra suggests that it is related to the youngest German volcano, Ulmener Maar, nearby. Radiocarbon dating of wood from the base of the Ulmener Maar Tephra at two locations provide ages in agreement with an accelerator mass spectrometer 14C date for the minerogenic layer from sediments of Lake Holzmaar situated 13 km south-west of Ulmener Maar. The mean radiocarbon age is 9 560 years BP. Dating by varve chronology provides an age of 10017 years VT (varve time in years before 1950) or 10 895 years corrected VT. Based on palynology the Ulmener Maar Tephra was deposited at the end of the Preboreal. High values of natural remnant magnetization intensity, typical of pyroclastic material, confirm that this minerogenic layer differs in composition from other clastic deposits of the sedimentary record. Geochemical analyses reveal increased values of total trace elements for the Laacher See Tephra and Ulmener Maar Tephra. An isopach map based on thickness variations of the Ulmener Maar Tephra at five investigated maar lakes indicates that the tephra was mainly transported to the south west.
TL;DR: In this article, a renormalization group analysis for a quasiperiodically forced nonlinear system near the onset of a strange nonchaotic attractor is developed and verified numerically.
Abstract: A renormalization group analysis is developed for a quasiperiodically forced nonlinear system near the onset of a strange nonchaotic attractor. The scaling properties for such an attractor are found and verified numerically.
TL;DR: A two-dimensional cellular automaton is introduced to model the flow and jamming of vehicular traffic in cities and the dependence of the average velocity of cars on the global traffic density is investigated.
Abstract: A two-dimensional cellular automaton is introduced to model the flow and jamming of vehicular traffic in cities. Each site of the automaton represents a crossing where a finite number of cars can wait approaching the crossing from each of the four directions. The flow of cars obeys realistic traffic rules. We investigate the dependence of the average velocity of cars on the global traffic density. At a critical threshold for the density the average velocity reduces drastically caused by jamming. For the low-density regime we provide analytical results which agree with the numerical results.
TL;DR: In this article, a non-lineaire equation differentielle nonlineaire is derived for des particles donné les surfaces ont une courbure arbitraire, which is resolue numeriquement dans le cas des particules spheriques.
Abstract: La theorie du contact elastique de deux corps developpee par Hertz [1] est generalisee tenant compte de la contribution des effects visqueux a la tension totale. Une equation differentielle nonlineaire est derivee pour des particles dont les surfaces ont une courbure arbitraire. Elle est resolue numeriquement dans le cas des particules spheriques. La dependence du coefficient de restitution normale de la vitesse d'impact est calculee et comparee avec des donnees experimentales obtenues pour la glace aux temperatures basses [2,3]. Un bon accord est trouve qui permet l'estimation des constantes du materiel dans certains cas. Une application astrophysique de nos resultats est discutee brevement dans un cas d'interet particulier : des particles de glace dans des anneaux planetaires.
TL;DR: In this and a subsequent paper, by means of an extension of the notion of fuzzy filter, a new approach to fuzzy topology is presented.
TL;DR: In this paper, the authors construct families of wavelets that minimize an uncertainty relation associated with square integrable representations of some canonical groups, and obtain a new interpretation of the Mexican hat function.
Abstract: In this paper, we construct families of wavelets that minimize an uncertainty relation associated with square integrable representations of some canonical groups. Especially, we obtain a new interpretation of the Mexican hat function.
TL;DR: In this paper, multilayers of quinoprotein glucose dehydrogenase were assembled onto modified gold electrodes, and the dependence of the electrode response on the number of enzyme layers showed that the transition from a kinetic to a diffusion-limited sensor is reached at 6−7 enzyme layers.
TL;DR: In this paper, the authors describe a solid-state master oscillator-amplifier-laser (MOPA) with a minimum number of elements for the double-pass single-rod amplifier.
Abstract: We describe a solid-state master oscillator-amplifier-laser (MOPA) with a minimum number of elements for the double-pass single-rod amplifier. It produces 100-W average output power of pulsed light with an almost diffraction limited beam. The Q-switched system works with an average repetition rate of about 3 kHz and the pulse width was 70 ns. As active material we used Nd:YALO (Nd:YAP) which has negligible depolarization. The strong thermal lens of the material with focal lengths of less than 15 cm at pump powers of 8 kW was compensated by a phase conjugating mirror based on stimulated Brillouin scattering (SBS). Therefore, the output power could be varied from 2 W up to 100 W without changing the transversal beam profile. The total efficiency of the amplifier including the phase conjugator is 1.25%. >
TL;DR: In situ hybridization revealed that rIRK3 mRNA is distributed throughout the brain and occurs predominantly in the piriform cortex, indusium griseum, supraoptic nucleus, facial nucleus and cerebellar Purkinje cells.
TL;DR: In this article, a new model for the description of complex granular particles and their interaction in molecular dynamics simulations of granular material in two dimensions is proposed, where the grains are composed of triangles which are connected by deformable beams.
Abstract: We propose a new model for the description of complex granular particles and their interaction in molecular dynamics simulations of granular material in two dimensions. The grains are composed of triangles which are connected by deformable beams. Particles are allowed to be convex or concave. We present first results of simulations using this particle model.
TL;DR: In this article, the state as an actor that can create, rearrange or even destroy established structures of interest representation is discussed, through small, often almost overlooked, and sometimes even failed interventions, governmental policies create a legacy that can serve as a springboard for further political action.
Abstract: The focus of this article is on the state as an actor that can create, rearrange or even destroy established structures of interest representation. Through small, often almost overlooked, and sometimes even failed interventions, governmental policies create a legacy that can serve as a springboard for further political action. This policy dynamic is triggered by “architectural” activities of the state, aiming at the structure of the interest group system. This kind of policy bears the potential not only to manipulate the structure, but also the preferences and strategies of interest groups so as to overcome their veto-power. The case of German health care reform policies since the late 1970s is used to illustrate how suck a kind of governmental “design” has exerted a decisive impact on the structure of the policy field, culminating in an unexpected legislative success for the federal government.1
TL;DR: In this article, the authors investigate the flow of granular material in a rotating cylinder numerically using molecular dynamics in two dimensions, and describe the particles by a new model which allows to simulate geometrically complicated shaped grains.
Abstract: We investigate the flow of granular material in a rotating cylinder numerically using molecular dynamics in two dimensions. The particles are described by a new model which allows to simulate geometrically complicated shaped grains. The results of the simulation agree significantly better with experiments than the results which are based on circular particles.
TL;DR: In this article, the authors characterize the topological space whose points are the 3-dimensional oriented homogeneous Riemannian manifolds; locally isometric manifolds are considered as identical.
Abstract: Space-times which allow a slicing into homogeneous spatial hypersurfaces generalize the usual Bianchi models. One knows already that in these models the Bianchi type may change with time. Here we show which of the changes really appear. To this end we characterize the topological space whose points are the 3-dimensional oriented homogeneous Riemannian manifolds; locally isometric manifolds are considered as identical.
TL;DR: In this article, the double orthogonality bases in the Cauchy problem for systems with injective symbols are derived and a solvability condition and a Carleman formula for the solution of the problem are given.
Abstract: Principles for applications of double orthogonality bases in the Cauchy problem for systems with injective symbols are derived. We obtain a solvability condition and a Carleman formula for the solution of the problem.
TL;DR: In this paper, the authors characterize the topological space whose points are the 3-dimensional oriented homogeneous Riemannian manifolds; locally isometric manifolds are considered as same.
Abstract: Space-times which allow a slicing into homogeneous spatial hypersurfaces generalize the usual Bianchi models. One knows already that in these models the Bianchi type may change with time. Here we show which of the changes really appear. To this end we characterize the topological space whose points are the 3-dimensional oriented homogeneous Riemannian manifolds; locally isometric manifolds are considered as same.
TL;DR: In this paper, side-group liquid-crystalline polymers with fluorine-containing mesogens were synthesized and characterized by size exclusion chromatography (SEC) and differential scanning calorimetry (DSC).
TL;DR: In this article, a model of mantle convection, including the volatile exchange between mantle and surface reservoirs, is used to study the thermal history of the Earth and the influence of dissolved volatiles on mantle rheology is reformulated.
TL;DR: In a human small-cell lung carcinoma cell line with endogenous VP gene expression, glucocorticoid administration results in elevated rather than diminished VP messenger RNA (mRNA) levels, suggesting an interaction of different transcription factors.
Abstract: Publisher Summary This chapter describes the vasopressin (VP) and oxytocin (OT) gene expression and regulation. The nonapeptides VP and OT, the major secretory products of magnocellular neurons of the hypothalamo–neurohypophysial system, are synthesized as parts of larger precursor proteins in different subsets of hypothalamic cells. They consist of a hydrophobic signal peptide at their N-terminal ends and the hormone moiety followed by the sequence Gly-Lys-Arg, the signal for hormone modification and precursor processing, respectively. Their major part is contributed by the carrier proteins, the neurophysins. The VP precursor only contains an additional component, the glycopeptide (GP). In a human small-cell lung carcinoma cell line with endogenous VP gene expression, glucocorticoid administration results in elevated rather than diminished VP messenger RNA (mRNA) levels. The effect was seen only upon costimulation with analogs of cAMP, pointing toward an interaction of different transcription factors. The somatic recombination between the VP and OT genes in hypothalamic neuron are also elaborated in the chapter.