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Showing papers by "Karlsruhe Institute of Technology published in 1993"


Proceedings ArticleDOI
28 Mar 1993
TL;DR: A learning algorithm for multilayer feedforward networks, RPROP (resilient propagation), is proposed that performs a local adaptation of the weight-updates according to the behavior of the error function to overcome the inherent disadvantages of pure gradient-descent.
Abstract: A learning algorithm for multilayer feedforward networks, RPROP (resilient propagation), is proposed. To overcome the inherent disadvantages of pure gradient-descent, RPROP performs a local adaptation of the weight-updates according to the behavior of the error function. Contrary to other adaptive techniques, the effect of the RPROP adaptation process is not blurred by the unforeseeable influence of the size of the derivative, but only dependent on the temporal behavior of its sign. This leads to an efficient and transparent adaptation process. The capabilities of RPROP are shown in comparison to other adaptive techniques. >

4,319 citations



Journal ArticleDOI
TL;DR: An elaborate combination of various techniques has enabled us to track vehicles under complex illumination conditions and over long monocular image sequences, and open problems as well as future work are outlined.
Abstract: Moving vehicles are detected and tracked automatically in monocular image sequences from road traffic scenes recorded by a stationary camera. In order to exploit the a priori knowledge about shape and motion of vehicles in traffic scenes, a parameterized vehicle model is used for an intraframe matching process and a recursive estimator based on a motion model is used for motion estimation. An interpretation cycle supports the intraframe matching process with a state MAP-update step. Initial model hypotheses are generated using an image segmentation component which clusters coherently moving image features into candidate representations of images of a moving vehicle. The inclusion of an illumination model allows taking shadow edges of the vehicle into account during the matching process. Only such an elaborate combination of various techniques has enabled us to track vehicles under complex illumination conditions and over long (over 400 frames) monocular image sequences. Results on various real-world road traffic scenes are presented and open problems as well as future work are outlined.

742 citations


Journal ArticleDOI
TL;DR: The τ decay library TAUOLA as discussed by the authors has been enriched with more than twenty decay channels, including leptonic modes τ- → nνe-to nνμ-(γ), (b) one-meson modes: νπ-, νK-, (c) t wo-mesons modes: τπ-π- π0(ϱ-), νk0π- (K∗-), etc.

575 citations


Journal Article
TL;DR: The observation that CD44 variants containing a protein domain of CD44 that confers full metastatic potential to rat carcinoma and sarcoma cell lines is increasingly expressed during colorectal tumor progression indicates that this domain may have an important role in tumor progression and metastasis in humans.
Abstract: Specific CD44 variant glycoproteins are overexpressed at particular stages of colorectal tumor progression. Some variants of the CD44 glycoprotein without exon v6 sequences appear at the earliest stage of tumorigenesis, i.e., in early adenomas. Expression of variants containing exon v6 sequences is largely restricted to the advanced stages of tumor development and in addition is more prevalent and intense in metastatic (Dukes C/D) than in nonmetastatic (Dukes A/B) carcinomas. The observation that CD44 variants containing a protein domain of CD44 that confers full metastatic potential to rat carcinoma and sarcoma cell lines is increasingly expressed during colorectal tumor progression indicates that this domain may have an important role in tumor progression and metastasis in humans. Information on v6 expression, which can be obtained by routine immunohistochemistry, may prove of important prognostic value, particularly in carcinomas (Dukes A and B) that have not yet given rise to detectable metastases.

566 citations


Journal ArticleDOI
TL;DR: In this paper, the shape of the in vivo reflection spectra is interpreted taking into account (a) the formation of pigment-protein complexes, (b) the sieve effect and the detour effect, as well as the reflection, refraction and scattering of light inside the leaf tissue.
Abstract: In vivo reflection spectra of intact bean leaves (Phaseolus vulgaris) were measured between 400 and 800 nm under remote sensing conditions (illumination with white light, detection of a narrow angle of the reflected light) using the VIRAF spectrometer. The leaves with colours from yellow to green were chosen at different times during light-induced greening. The colours of the leaves were characterized by the chromaticity coordinates according to CIE 1931 calculated from the reflection spectra. The influence of the absorption of chlorophyll—the main pigment of green leaves—on the reflection spectrum of leaves is outlined. The shape of the in vivo reflection spectra is interpreted taking into account (a)the formation of pigment-protein complexes, (b) the sieve effect and the detour effect, as well as (c) the reflection, refraction and scattering of light inside the leaf tissue. Reflection signals at several distinct wavelengths and their ratios as well as the inflection point of the reflection ris...

460 citations


Journal ArticleDOI
TL;DR: In this paper, mycobacterium sp. strain BB1 was isolated from a former coal gasification site and was able to utilize phenanthrene, pyrene, and fluoranthene as sole sources of carbon and energy and to degrade fluorene cometabolically.
Abstract: Mycobacterium sp. strain BB1 was isolated from a former coal gasification site. It was able to utilize phenanthrene, pyrene, and fluoranthene as sole sources of carbon and energy and to degrade fluorene cometabolically. Exponential growth with solid phenanthrene, pyrene, and fluoranthene was obtained in fermentor cultures. The growth rates were 0.069, 0.056, and 0.040 h-1, respectively. Several metabolites of phenanthrene and fluorene metabolism were identified.

358 citations


Proceedings ArticleDOI
24 May 1993
TL;DR: A formalism for expressing trust relations is presented along with an algorithm for deriving trust relations from recommendations, and the advantages of the approach are demonstrated by analyzing and comparing the trust relation requirements of a few known authentication protocols.
Abstract: The notion of trust is fundamental in inter-domain authentication protocols. The goal is to develop an effective formalism for explicit expressions of trust relations between entities involved in authentication protocols. Different relevant types of trust are identified and classified. A formalism for expressing trust relations is presented along with an algorithm for deriving trust relations from recommendations. The advantages of the approach are demonstrated by analyzing and comparing the trust relation requirements of a few known authentication protocols. >

294 citations


Journal ArticleDOI
TL;DR: Bacterial N oxide metabolism is related to cellular bioenergetics and processes of nitrogen assimilation, and the interest in nitric oxide (NO) centers around the dissimilatory transformation of nitrate, better known as the denitrification process.
Abstract: Bacterial N oxide metabolism is related to cellular bioenergetics and processes of nitrogen assimilation. The interest in nitric oxide (NO) centers around the dissimilatory transformation of nitrate, better known as the denitrification process. Denitrification [described as phenomenon more than 100 years ago (Gayon and Dupetit 1886)], is a distinctive mode of respiration that satisfies the bioenergetic needs of a great variety of bacteria by transforming oxyanions of nitrogen to Nz, mainly under conditions of reduced oxygen tension or strict anaerobiosis. The reaction reverses nitrogen fixation in the biogeochemical N cycle sustained by prokaryotes. Denitrification is controlled by the metalloenzymes nitrate reductase, nitrite reductase, nitric oxide reductase, and nitrous oxide (N20) reductase and involves the corresponding enzyme substrates. The same magnitude of nitrogen fixed yearly by biological and abiological processes [combined estimates vary between 254 to 406 million tons N (Jenkinson 1990)] has to be returned to N 2 by denitrification to close the N cycle. However, because of the large anthropogenic contribution, fixation and denitrification are not balanced anymore as evident from the steady increase of nitrate in the environment. A second concern focussing around NO and the conditions of its microbial formation, is the nitrosation of secondary amines in the etiology of certain types of cancer. Since the discovery of NO in 1987 as a vasodilatory messenger (Ignarro et al. 1987; Palmer et al. 1987), the biomedical community is astounded by the diverse roles of NO in cellular communication including the central and peripheral nervous system, and in host defense mechanisms of eukaryotes (for reviews see Marletta et al. 1990; Moncada 1992; Nathan 1992; Traylor and Sharma 1992: Edelman and Gally 1992). Yet NO is not an obscure chemical and certainly no newcomer to the life sciences, as often stated in hyperbole. Early in evolution NO took its role as a central player in bacterial bioenergetics and in the global N cycle vital to all organisms. The chemistry of NO in biological systems and that of the nitroxyl anion (NO-) and nitrosonium cation (NO +) has been reviewed briefly (Stamler et al. 1992c; see also comment by Bonner and Hughes 1993). Another remarkable finding is the formation of N20 from nitrite, sometimes accompanied by NO production, by the fungus impetfectus Fusarium oxysporum and telemorphic and anamorphic relatives (Shoun et al. 1992). These fungi synthesize a special cytochrome P-450 induced only in the presence of nitrite (Shoun and Tanimoto 1991), which has been shown to have NO reductase activity (Nakahara et al. 1993). The existence of such a hemoprotein is of interest in the context that the cytokine (interferon-7 and lipopolysaccharide)-inducible form of NO synthase from macrophages is a cytochrome P-450 (White and Marletta 1992); also hepatic cytochrome P-450 monooxygenases are able to convert the Na-hydroxy-activated form of L-arginine to NO (Boucher et al. 1992). In another fungus, the slime mold Dictyostelium discoideum, NO alters the cellular aggregation behavior via ADP-ribosylation of a cytoplasmic 41-kDa protein (Tao et al. 1992). Principles of bacterial NO metabolism were spelled out nearly 40 years ago. NO was found as a product of denitrification from a clay loam microcosm with 15N nitrate as tracer (Wijler and Delwiche 1954). The study of nitrite utilization with Thiobacillus denitr~'cans established that NO was consumed and produced by a defined axenic culture (Baalsrud and Baalsrud 1954). NO was given status of an intermediate in bacterial denitrification, first as the result of studies with intact cells (Iwasaki etal. 1956; Matsubara and Mori 1968) and later from recognition that cell-free extracts of \"Pseudomonas denitr~'cans\" reduce exogenous NO (Miyata et al. 1969). Around that time Pseudomonas stutzeri ZoBell (formerly P. perfectomarina) was introduced to denitrification research and a pathway identical to that of Mori and coworkers was formulated (Payne et al. 1971):

270 citations


Journal ArticleDOI
TL;DR: The spin Berry phase can be observed in conductance experiments on rings of noncentrosymmetric materials and results in destructive interference and in the shift of the Aharonov-Bohm oscillations.
Abstract: The spin Berry phase can be observed in conductance experiments on rings of noncentrosymmetric materials. It results in destructive interference and in the shift of the Aharonov-Bohm oscillations. The spin-orbit interaction in vacuumlike Aharonov-Bohm experiments leads to the opposite sign of the magnetoresistance in comparison with the weak localization regime in disordered conductors. A time-dependent uniaxial strain results in current in a ring.

236 citations


Journal ArticleDOI
TL;DR: In this article, the epsilon budget of the k-epsilon model for fully developed channel flow is derived from direct numerical simulation (DNS) data for developed channel and boundary layer flow at two Reynolds numbers each.
Abstract: The constant C sub mu and the near-wall damping function f sub mu in the eddy-viscosity relation of the k-epsilon model are evaluated from direct numerical simulation (DNS) data for developed channel and boundary layer flow at two Reynolds numbers each. Various existing f sub mu model functions are compared with the DNS data, and a new function is fitted to the high-Reynolds-number channel flow data. The epsilon-budget is computed for the fully developed channel flow. The relative magnitude of the terms in the epsilon-equation is analyzed with the aid of scaling arguments, and the parameter governing this magnitude is established. Models for the sum of all source and sink terms in the epsilon-equation are tested against the DNS data, and an improved model is proposed.

Journal ArticleDOI
TL;DR: The results of a systematic study of the reactivity of 13 selected flavonoids (from the flavonol, flavone, flavanone and flavane families) with singlet oxygen (1O2(1 delta g)) in order to establish a structure-activity relationship were reported in this paper.
Abstract: Flavonoids, polyphenolic pigments widely present in plants, have been reported to act as scavengers of various oxidizing species. However, most often an overall antioxidant effect was measured. In this paper we report the results of a systematic study of the reactivity of 13 selected flavonoids (from the flavonol, flavone, flavanone and flavane families) with singlet oxygen (1O2(1 delta g)) in order to establish a structure-activity relationship. The rate constants of the chemical reaction of these flavonoids with 1O2(k r) and their rate constants of 1O2 physical quenching (kq) have been determined by kinetic measurements and near-IR singlet oxygen luminescence. The efficiency of the physical quenching is mainly controlled by the presence of a catechol moiety on ring B, whereas the structure of ring C (particularly the presence of a hydroxyl group activating the double bond) is the main factor determining the efficiency of the chemical reactivity of these compounds with 1O2. The total reactivity factor determining the efficiency of the chemical reactivity of these compounds with 1O2. The total reactivity scale is dominated by kq, which is in general higher than kr. (+)-Catechin is the most efficient quencher of the series.

Journal ArticleDOI
TL;DR: Wave interactions, like diffraction and scattering, over the propagation path are described by the uniform theory of diffraction (UTD) and physical optics (PO) and models for rural and urban areas are presented for 2-D and 3-D ray tracing.
Abstract: Mobile communication links are severely influenced by propagation effects. Wave propagation in the VHF/UHF frequency range over natural and man-made terrain is strongly dependent on topography and morphography. Propagation modeling is based on a ray-optical approach. Wave interactions, like diffraction and scattering, over the propagation path are described by the uniform theory of diffraction (UTD) and physical optics (PO). Propagation models for rural and urban areas are presented for 2-D and 3-D ray tracing. Near-range models apply to the corresponding areas in forest and urban sites. The field-strength delay spectrum describes ray contributions with deterministic amplitudes but statistical phases are used to derive time-and frequency-domain channel characteristics. Comparisons between measured and predicted data are presented. >

Journal ArticleDOI
01 Aug 1993
TL;DR: In this paper, a 3D Kirchhoff-type prestack migration approach is proposed where the primary reflections of the wavefields to be imaged are a priori described by the zero-order ray approximation.
Abstract: Compressional primary nonzero offset reflections can be imaged into three‐dimensional (3-D) time or depth‐migrated reflections so that the migrated wavefield amplitudes are a measure of angle‐dependent reflection coefficients. Various migration/inversion algorithms involving weighted diffraction stacks recently proposed are based on Born or Kirchhoff approximations. Here a 3-D Kirchhoff‐type prestack migration approach is proposed where the primary reflections of the wavefields to be imaged are a priori described by the zero‐order ray approximation. As a result, the principal issue in the attempt to recover angle‐dependent reflection coefficients becomes the removal of the geometrical spreading factor of the primary reflections. The weight function that achieves this aim is independent of the unknown reflector and correctly accounts for the recovery of the source pulse in the migrated image irrespective of the source‐receiver configurations employed and the caustics occurring in the wavefield. Our weight ...

Journal ArticleDOI
TL;DR: This work describes an algorithm which will produce, from a formula in monadic second order logic and an integer k such that the class defined by the formula is of treewidth ≤ k, a set of rewrite rules that reduces any member of the class to one of finitely many graphs, in a number of steps bounded by the size of the graph.
Abstract: We show how membership in classes of graphs definable in monadic second order logic and of bounded treewidth can be decided by finite sets of terminating reduction rules. The method is constructive in the sense that we describe an algorithm which will produce, from a formula in monadic second order logic and an integer k such that the class defined by the formula is of treewidth ≤ k, a set of rewrite rules that reduces any member of the class to one of finitely many graphs, in a number of steps bounded by the size of the graph. This reduction system corresponds to an algorithm that runs in time linear in the size of the graph.

Journal ArticleDOI
TL;DR: This article discusses the following recommendations: nightwork should be reduced as much as possible, quickly rotating shift systems are preferable to slowly rotating ones, and flexible working time arrangements are realizable.
Abstract: All shift systems have advantages and drawbacks. There is no single 'optimum shift system' which can be used in industry or commerce at all work places. However, there are shift systems which are more favourable, and others which are less favourable, in the context of physiological, psychological, and social recommendations for the design of shift systems. This article discusses the following recommendations: (1) Nightwork should be reduced as much as possible. If this is not possible, quickly rotating shift systems are preferable to slowly rotating ones. Permanent nightwork does not seem to be advisable for the majority of shiftworkers. (2) Extended workdays (9-12 h) should only be contemplated, if the nature of work and the workload are suitable; the shift system is designed to minimize the accumulation of fatigue; there are adequate arrangements for cover of absentees; overtime will not be added; toxic exposure is limited; and if it is likely that a complete recovery after work and a high acceptance of the working time arrangement are possible. (3) An early start for the morning shift should be avoided. In all shiftsystems flexible working time arrangements are realizable. The highest flexibility is possible in 'time autonomous groups'. (4) Quick changeovers (e.g., from night to afternoon shift at the same day or from afternoon to morning shift) must be avoided. The number of consecutive working days should be limited to 5-7 days. Every shift system should include some free weekends with at least two successive full days off. (5) The forward rotation of shifts (phase delay, clockwise rotation) would seem to be recommendable at least in continuous shift systems. Besides the design of a shift system, implementation strategy is of particular importance for the acceptance of the shift system.

Journal ArticleDOI
TL;DR: In this article, the authors simplify the light-cone gauge description of a relativistic membrane moving in Minkowski space by performing a field-dependent change of variables which allows the explicit solution of all constraints and a Hamiltonian reduction to a SO(1, 3) invariant 2 + 1-dimensional theory of isentropic gas dynamics, where the pressure is inversely proportional to (minus) the mass density.

Journal ArticleDOI
TL;DR: A semidirect implementation of the closed‐shell MP2 gradient for efficient use on workstation computers is presented, based on the algorithm proposed by Frisch and coworkers but includes several modifications to reduce disk storage requirements and exploits nonabelian point group symmetry.
Abstract: A semidirect implementation of the closed-shell MP2 gradient for efficient use on workstation computers is presented. The approach is based on the algorithm proposed by Frisch and coworkers but includes several modifications to reduce disk storage requirements and exploits nonabelian point group symmetry. The performance of the resulting program MPGRAD (BIOSYM Corp., San Diego, CA) is demonstrated in applications to the molecules [AlSi(CH3)3]4 and ferrocene. The largest calculation involved 492 basis functions and was carried out on IBM RS/6000 workstations with memory sizes of 32 and 128 Mb. The ratio of CPU to wallclock time exceeds 90% in all typical applications. © 1993 John Wiley & Sons, Inc.

Book ChapterDOI
01 Jan 1993
TL;DR: In this paper, the vortex shedding flow past a square cylinder at Re = 22.000 was calculated with various turbulence models and the 2D periodic shedding motion was resolved in an unsteady calculation, and the superimposed stochastic turbulent fluctuations were simulated both with the k-eddy-viscocity model and with a Reynolds-stress equation model.
Abstract: The vortex-shedding flow past a square cylinder at Re = 22.000 was calculated with various turbulence models. The 2D periodic shedding motion was resolved in an unsteady calculation, and the superimposed stochastic turbulent fluctuations were simulated both with the k — e eddy-viscocity model and with a Reynolds-stress equation model. For both models, the viscosity-affected near-wall region was either bridged by wall functions or was resolved with a simpler one-equation model using a prescribed length-scale distribution. The k — e model with wall functions does not yield unsteady vortex motion while the other model variants do. The two-layer k —e model underpredicts severely the periodic fluctuations and also the Strouhal number and drag coefficient. The Reynoldsstress-equation models yield considerably better agreement with experiments, but tend to overpredict the periodic fluctuating motion and also miss some other details of the flow behaviour.

Book
01 Mar 1993
TL;DR: In this paper, the authors present a set of tools for manufacturing systems in the CAM area, including communication nets and protocol standards, process planning and scheduling, and flexible manufacturing and assembly equipment.
Abstract: 1. The Manufacturing System. 2. CIM Models and Concepts. 3. Analysis Tools for Manufacturing. 4. Flexible Manufacturing and Assembly Equipment. 5. Control Structures for Manufacturing Systems in the CAM Area. 6. Communication Nets and Protocol Standards. 7. CAD: Its Role in Manufacturing. 8. Process Planning and Manufacturing Scheduling. 9. Robotics. 11. City Assurance. 12. References and Further Reading. Index.

Journal ArticleDOI
TL;DR: A novel formulation of MP2 theory is presented which starts from the Laplace transform MP2 ansatz, and subsequently moves from a molecular orbital (MO) representation to an atomic orbital (AO) representation, and the new formulation is denoted AO-MP2.
Abstract: A novel formulation of MP2 theory is presented which starts from the Laplace transform MP2 ansatz, and subsequently moves from a molecular orbital (MO) representation to an atomic orbital (AO) representation. Consequently, the new formulation is denoted AO-MP2. As in traditional MP2 approaches electron repulsion integrals still need to be transformed. Strict bounds on the individual MP2 energy contribution of each intermediate four-index quantity allow to screen off numerically insignificant integrals with a single threshold parameter. Implicit in our formulation is a bound to two-particle density matrix elements. For small molecules the computational cost for AO-MP2 calculations is about a factor of 100 higher than for traditional MO-based approaches, but due to screening the computational effort in larger systems will only grow with the fourth power of the size of the system (or less) as is demonstrated both in theory and in application. MP2 calculations on (non-metallic) crystalline systems seem to be a feasible extension of the Laplace transform approach. In large molecules the AO-MP2 ansatz allows massively parallel MP2 calculations without input/output of four-index quantities provided that each processor has in-core memory for a limited number of two-index quantities. Energy gradient formulas for the AO-MP2 approach are derived.

Journal ArticleDOI
TL;DR: A function-based communication model that allows applications to request individually tailored services from the communication subsystem is presented, and the concept of layering is abandoned for both flexibility and efficiency reasons.
Abstract: A function-based communication model that allows applications to request individually tailored services from the communication subsystem is presented. Based on service requirements and available resources, suitable protocol machines are configured to serve the application. This configuration is done using a proper combination of functional modules. The concept of layering is therefore abandoned for both flexibility and efficiency reasons. >

Journal ArticleDOI
TL;DR: In this article, the operating characteristics of a new aerosol generator for the production of "soot-like" particles have been investigated and the size distribution of the primary particles was measured for different operating parameters using a differential mobility analyser and an aerosol electrometer.

Journal ArticleDOI
14 Oct 1993-Nature
TL;DR: In this article, the authors report estimates of the magnitude of in situstresses to 6 km depth in the KTB borehole in southern Germany, and suggest that plate-driving forces in the continental lithosphere in this part of western Europe are transmitted principally through the upper crust.
Abstract: IT has been suggested1–6that in many cases the average strength of the continental crust is quite low (tens of megapascals), so that the crust has little effect on the large-scale deformation of the lithosphere. But laboratory friction studies7,8, combined with simple faulting theory9,10 (as well as extrapolation ofin situ stress measurements from the upper 3 km of the crust11), imply that if pore pressure is approximately hydrostatic at mid-crustal depth, crustal strength is appreciable (hundreds of megapascals) and would markedly constrain the nature of lithospheric deformation12–15. Here we report estimates of the magnitude of in situstresses to 6 km depth in the KTB borehole in southern Germany. Our results indicate a high-strength upper crust, in which the state of stress is in equilibrium with its frictional strength. We suggest that plate-driving forces in the continental lithosphere in this part of western Europe are transmitted principally through the upper crust, and that this may also be the case in other continental areas of moderate to elevated heat flow.

Journal ArticleDOI
TL;DR: In this article, a CCSD and TCSD investigation of carbonyl oxide (1) and its cyclic isomer dioxirane (2) has been carried out employing DZ + P and TZ + 2P basis sets.

Book ChapterDOI
30 Aug 1993
TL;DR: This paper contains the first (to the authors' knowledge) proposal to optimize nested queries in the object-oriented context and translates queries to nested algebraic expressions to allow for more efficient evaluation.
Abstract: Many declarative query languages for object-oriented databases allow nested subqueries This paper contains the first (to our knowledge) proposal to optimize them A two-phase approach is used to optimize nested queries in the object-oriented context The first phase—called dependency-based optimization—transforms queries at the query language level in order to treat common subexpressions and independent subqueries more efficiently The transformed queries are translated to nested algebraic expressions These entail nested loop evaluation which may be very inefficient Hence, the second phase unnests nested algebraic expres­sions to allow for more efficient evaluation

Journal ArticleDOI
TL;DR: Future studies should investigate why utilization of dry diets depends on presence of the stomach; define more precisely the quantitative feed requirements of larvae; and search those diet-induced qualitative differences of larval metabolism which affect growth performance.
Abstract: Studies on the nutritional physiology of larval fish should provide the basis for defining the length of the larval period and for understanding the quantitative and the qualitative feed requirements of the larvae. For these purposes, it is necessary to perform both descriptive investigations on the ontogenesis of structures and functions as well as experimental investigations on adaptive strategies of the larvae under changing feeding regimes. In the present communication, examples of both approaches are discussed comparing three species: African catfish Clarias gariepinus, whitefish Coregonus lavaretus, and turbot Scophthalmus maximus. At the onset of exogenous feeding, the digestive system of all three species is sufficiently developed to ensure efficient utilization of live food, but not of dry food. A major event during the subsequent development is the differentiation of the stomach. Evidence exists that for turbot and catfish, a functional stomach is necessary to utilize dry feeds as efficiently as live feeds. Therefore, from a nutritional point of view, in those two species the larval period, during which a special larval diet has to be given, ends with the completion of stomach differentiation. The capacity of the larvae to acclimate physiologically to different nutritional conditions seems to be limited. Using general nutritional indices such as protease activity, RNA/DNA ratio, midgut cell height or nuclear diameter of hepatocytes, larvae of the three species show partly starvation symptoms when reared on dry food. This effect can be explained to some extent by quantitative considerations, i.e., lower food consumption and digestibility is less for dry diets than for live diets. The contribution of the qualitative factors involved in the different performance of larvae reared on dry or live food is presently not well understood. Future studies should: 1) investigate why utilization of dry diets depends on presence of the stomach; 2) define more precisely the quantitative feed requirements of larvae; and 3) search those diet-induced qualitative differences of larval metabolism which affect growth performance.

Proceedings ArticleDOI
27 Apr 1993
TL;DR: The authors show how recognition performance in automated speech perception can be significantly improved by additional lipreading, so called speech-reading, on an extension of a state-of-the-art speech recognition system, a modular multistage time delay neural network architecture (MS-TDNN).
Abstract: The authors show how recognition performance in automated speech perception can be significantly improved by additional lipreading, so called speech-reading. They show this on an extension of a state-of-the-art speech recognition system, a modular multistage time delay neural network architecture (MS-TDNN). The acoustic and visual speech data are preclassified in two separate front-end phoneme TDNNs and combined with acoustic-visual hypotheses for the dynamic time warping algorithm. This is shown on a connected word recognition problem, the notoriously difficult letter spelling task. With speech-reading, the error rate could be reduced by up to half of the error rate of the pure acoustic recognition. >

Journal ArticleDOI
TL;DR: In this paper, a numerical simulation of patterns of shear bands in biaxial compression tests using an elasto-plastic Cosserat constitutive equation is presented.
Abstract: Numerical simulation of patterns of shear bands in biaxial compression tests using an elasto-plastic Cosserat constitutive equation is presented. Random distribution of the material properties acts as a trigger for the localized deformation. Two types of stress-strain curves, namely strain softening and strain softening followed by strain hardening, are investigated. It is shown that the characteristic of the stress-strain curve is crucial for the patterning of shear bands. While calculations with the stress-strain curve with solely softening yield only one single shear band, a flock of shear bands can be obtained with the stress-strain curve with softening followed by hardening. Benefited from the characteristic length provided by the Cosserat elasto-plastic constitutive equation, the dependence of the calculation on the mesh-size is avoided.

Journal ArticleDOI
TL;DR: This work evaluated the interference effect on the transport through an NS tunnel junction and proposed the layouts to observe drastic Aharonov-Bohm and Josephson effects.
Abstract: The subgap conductivity of a normal-superconductor (NS) tunnel junction is thought to be due to tunneling of two electrons. There is a strong interference between these two electrons, originating from the spatial phase coherence in the normal metal at a mesoscopic length scale and the intrinsic coherence of the superconductor. We evaluated the interference effect on the transport through an NS tunnel junction. We propose the layouts to observe drastic Aharonov-Bohm and Josephson effects