Showing papers by "University of Paderborn published in 1988"
TL;DR: The Min Cut Linear Arrangement Problem is NP-complete for trees with polynomial size edge weights and this is used to show the NP-completeness of Search Number, Vertex Separation, Progressive Black/White Pebble Demand, and Topological Bandwidth for planar graphs with maximum vertex degree 3.
159 citations
TL;DR: From these experiments, the influence of biofilm diffusion limitation on reaction kinetics and criteria for stable biofilm formation on sand particles were obtained.
Abstract: Naphthalene-2-sulfonate was degraded by submerse growing Pseudomonads in a chemostat culture. The kinetic parameters for the Monod equation, including Pirts maintenance energy, were calculated from these experiments regarding naphthalene-2-sulfonate as substrate and oxygene as cosubstrate. By immobilizing the bacteria on sand particles, the degradation of naphthalene-2-sulfonate was carried out in a specialy designed three-phase airlift-loop reactor in a completely fluidized state. From these experiments, the influence of biofilm diffusion limitation on reaction kinetics and criteria for stable biofilm formation on sand particles were obtained.
66 citations
28 Jun 1988
TL;DR: This paper describes how to embed an arbitrary binary tree with dilation 3 and O(1) expansion into a hypercube and shows that all binary trees can be embedded into their optimal hypercube withdilation 3.
Abstract: We describe how to embed an arbitrary binary tree with dilation 3 and O(1) expansion into a hypercube. (In fact, we show that all binary trees can be embedded into their optimal hypercube with dilation 3, provided that all binary trees with no more than B vertices, for some fixed number B, can be embedded with dilation 3.) We also show how to embed all binary trees into their optimal hypercube with dilation 5.
56 citations
TL;DR: In this paper, the authors measured spontaneous polarisation P s and tilt angle θ of induced ferroelectric S* c phases in mixed systems as a function of the mole fraction χ G.
50 citations
TL;DR: In this article, a fine-positioning controller for a rotary-actuator-type magnetic-storage disk drive was designed using the LQG (linear quadratic Gaussian) methodology and implemented on a digital signal processor.
Abstract: A fast fine-positioning controller has been designed for a rotary-actuator-type magnetic-storage disk drive. The controller was designed using the LQG (linear quadratic Gaussian) methodology and has been implemented on a digital signal processor. It is shown that LQG design is a viable approach, and that various problems associated with the structural resonances of the actuator can be solved. >
46 citations
TL;DR: The structure of the primary rhodium defect in Rhodium-doped AgCl was determined by EPR and electron-nuclear double-resonance technique (ENDOR) spectroscopies.
Abstract: The structure of the primary rhodium defect in rhodium-doped AgCl was determined by EPR and electron-nuclear double-resonance technique (ENDOR) spectroscopies. The substitutional and orthorhombic ${\mathrm{Rh}}^{2+}$ complex, (${\mathrm{RhCl}}_{6}$${)}^{4\mathrm{\ensuremath{-}}}$, was elongated along a [100] axis with a silver ion vacancy in a next-nearest-neighbor position in the plane perpendicular to the elongation axis. The large superhyperfine interactions measured for the first-shell chloride ions and the fourth-shell silver ions along the elongation axis suggest that the complex was stabilized by covalent interactions. The structural model deduced from these experiments provided an explanation for the dynamic behavior of the complex which was observed above \ensuremath{\sim}80 K.
27 citations
29 Aug 1988
TL;DR: This work reviews results on embedding network and program structures into popular parallel computer structures and describes high level descriptions of efficient methods to simulate an algorithm designed for one type of architecture on a different network structure.
Abstract: We review results on embedding network and program structures into popular parallel computer structures. Such embeddings can be viewed as high level descriptions of efficient methods to simulate an algorithm designed for one type of architecture on a different network structure and/or techniques to distribute data/program variables to achieve optimum use of all available processors.
27 citations
TL;DR: An incremental attribute evaluation algorithm is proposed that allows multiple subtree replacement and cancels three auxiliary tables required by the previous version.
Abstract: Three improvements are suggested upon an incremental attribute evaluation algorithm proposed by the first author. The resulting algorithm allows multiple subtree replacement and cancels three auxiliary tables required by the previous version.
23 citations
TL;DR: Both the Monod equation, and an extended model regarding the interspecies transfer of 5AS, were found to be suitable to describe the relationship between biomass and substrate concentration, depending on the flow rate of continuous culture.
Abstract: The degradation of 6-aminonaphthalene-2-sulphonic acid (6A2NS) by mixed cultures via an interspecies transfer of 5-aminosalicylic acid (5AS) was investigated using a continuous chemostat culture. Two different bacterial communities were employed. Steady-state data were obtained from a multi-species culture only, but not from a defined two-species culture. Experimental data showed the conversion of 6A2NS into 5AS to be rate-determining for degradation. Both the Monod equation, and an extended model regarding the interspecies transfer of 5AS, were found to be suitable to describe the relationship between biomass and substrate concentration, depending on the flow rate of continuous culture. Substrate consumed for endogenous metabolism was considred according to Pirt (1975).
21 citations
TL;DR: An economic model capable of simulating the 4 main historical stages of civilization: hunting, agricultural, industrial, and postindustrial is proposed, able to capture the salient features of economic development in the very long run.
21 citations
11 Apr 1988
TL;DR: In this article, it was shown that wave digital lattice filters with a bireciprocal characteristic function can be designed to have a linear phase in the pass band and a numerical example is given.
Abstract: It is shown that wave digital lattice filters can easily be designed to have a linear phase in the pass band. A numerical example is given, which shows that, in particular for wave digital lattice filters with a bireciprocal characteristic function, efficient linear phase realizations can be obtained. >
TL;DR: In the first part of the paper a set M ′ is constructed, the so-called set of events which is endowed with a causal structure and an atlas of coordinates.
TL;DR: In this article, a new definition based on the first moment with respect to space of the free-carrier distribution is proposed and a comparison between the theoretical and Monte Carlo results for the different approaches is made.
Abstract: Within the context of the multiple-trapping model, we discuss different theoretical ways of defining a transit time in the time-of-flight experiment. A new definition based on the first moment with respect to space of the free-carrier distribution is proposed. At the same time various experimentally used definitions of transit time are identified and the corresponding operational values are extracted from Monte Carlo simulated time-of-flight current traces for different field strengths and temperatures, with either an exponential or a linear density of tail states. A comparison between the theoretical and Monte Carlo results for the different approaches is made. Our calculations show that definitions of transit time that emphasize the fastest of the drifting carriers exhibit a larger electric field dependence and a smaller apparent activation energy than definitions which are based on the totality of excess charge carriers. Consequently we conclude that, if one analyses drift-mobility data in the...
TL;DR: Pentachlorobenzene and octachlorostyrene were decomposed in a vertically constructed combustion furnace applying different combustion temperatures (400°C, 600°C), 800°C and 1000°C).
TL;DR: In this article, the authors considered the problem of finding a solution of (1) that is differentiable with u′ Bochner integrable over a Banach space such that u(t) =X0 + ∫0 t u′(s)ds on J and u′∊F(t,u(t)) a.e.
Abstract: Let X be a Banach space, 2x\⊘ the nonempty subsets of X,J = [o,a]⊂R and F:J×X→2x\⊘ a multivalued map. We consider U′ ∊ F(t,u) a.e. on J, u(o) = Xp ∊ X. A solution of (1) is understood to be a.e. differentiable with u′ Bochner integrable over J such that u(t) =X0 + ∫0 t u′(s)ds on J and u′(t)∊F(t,u(t)) a.e. Under appropriate conditions on F the set S of solutions to (1) is compact ≠ ⊘ in CX (J), the space of continuous v : J → X with ∣v∣0 = max∣v(t)∣. We concentrate on maps F with F(t,.) upper semicontinuous andshow that S is connected or even a compact Rδ in the sense of Borsuk. This is interesting in itself, but also in connection with the multivalued Poincare map in case F is periodic in time.
TL;DR: In this paper, seven substituted 1,5-diphenylformazans were investigated as liquid-liquid extractants for extracting traces of silver in copper, ores and concentrates.
TL;DR: An effective method is presented for automatic construction of incremental LR( 1) parsers that allow multiple modifications of the original input as well as epsilon productions in the underlying LR(1) grammar.
Abstract: An effective method is presented for automatic construction of incremental LR(1) parsers. The resulting parsers allow multiple modifications of the original input as well as epsilon productions in the underlying LR(1) grammar. For parsing a modified input, their space require ment depends linear on the length of the input and their runtime is proportional to the total size of the modifications. The method has been implemented for experimental purposes.
TL;DR: In this paper, several chemically modified polystyrene-divinylbenzene packings for the separation of nitroarenes, polycyclic aromatic hydrocarbons and aminosubstituted aromatic molecules were investigated.
Abstract: One possible method of characterizing chemicall-modified stationary phases is to describe their chromatographic properties. In this study we investigated several chemically-modifiedpolystyrene-divinylbenzene packings for the separation of nitroarenes, polycyclic aromatic hydrocarbons and aminosubstituted aromatic hydrocarbons. Chromatography was carried out on commercially available polymer stationary phases, for example C-18 or vinylpyridine modified polystyrene. In addition, a chemically-immobilized polymer packing was prepared by introducing nitrogroups, which were established by elemental analysis and infrared spectroscopy.
TL;DR: In this paper, a model is proposed to explain the Grandjean-Cano lines occurring in wedge-shaped samples of liquid-crystalline blue phases I and II, where stretched and compressed areas of the cubic BP lattice edge dislocations occur which give rise to the observed Cano lines.
Abstract: A model is proposed to explain the Grandjean-Cano lines occurring in wedge-shaped samples of liquid-crystalline blue phases I and II. Between stretched and compressed areas of the cubic BP lattice edge dislocations occur which give rise to the observed Cano lines. The results for the BP I are in agreement with a b.c.c. lattice in (110) orientation parallel to the surface whereas for the BP II a s.c. lattice in (100) orientation was derived.
TL;DR: In this article, the authors investigated the performance of selenium and tellurium in silicon in the temperature range 1000°C to 1310°C by sheet conductivity, and the surface concentrations for both dopants were of the order of 5 × 1013 to 6×1016cm−3.
Abstract: Diffusion of selenium and tellurium in silicon has been investigated in the temperature range 1000°C to 1310°C by sheet conductivity. For Si∶SeD0= 0.3±0.1 cm2/s andh=2.6±0.1 eV, and for Si∶TeD0=0.9±0.3 cm2/s and h=3.3±0.1eV have been obtained. The surface concentrations for both dopants were of the order of 5 × 1013 to 6×1016cm−3. The Hall coefficient leads to an energy level of 300±15meV for selenium and 200±20meV for tellurium.
TL;DR: In this article, a thermodynamic field theory is given for media in thin, curved regions (interfaces with finite thickness), which separates two media with different physical properties, and a generalized transport equation and specific balance equations are derived.
Abstract: The nonequilibrium behavior for mixtures of fluids in interfaces is discussed. In particular, a thermodynamic field theory is given for media in thin, curved regions (interfaces with finite thickness), which separates two media with different physical properties. The moving interface is considered as semipermeable and a generalized transport equation and specific balance equations are derived. A systematic investigation of constitutive equations is made and in the limit as the thickness of the interface goes to zero it is shown that all relevant interfacial relations can be found.
TL;DR: In this article, the axial superhyperfine interaction with six neighbor fluorine ions has also been observed with axial spin Hamiltonians with an effective spin S = 1 2 and gz.370.
01 May 1988
01 Jan 1988
TL;DR: In this article, a finite element procedure has been constructed for the simulation of a quasistatic crack propagation along the prospective crack path known from a cooling experiment, and the stress intensity factors at the tips of propagating matrix cracks were determined.
Abstract: Branched thermal crack systems consisting of a combination of curvilinear matrix cracks and interface cracks, respectively, arising in self-stressed models of fibrous composites due to a steady cooling process are investigated by numerical as well as experimental methods of fracture mechanics. Further, by implementation of a maximum strain energy release rate criterion as well as by using the substructure technique a finite element procedure has been constructed for the simulation of a quasistatic crack propagation along the prospective crack path known from a cooling experiment. Finally, by using the method of caustics in transmission and reflection, respectively, stress intensity factors K, at the tips of propagating matrix cracks were determined. A comparison of those fracture mechanical quantities obtained experimentally with associated finite element calculations using a modified crack closure integral showed a very good agreement in the region of stable crack propagation.
TL;DR: In this article, the relationship between the total energy release rate G and the complex stress intensity factors K j (j= 1,2), respectively, was studied existing at the crack tip of a semi-infinite curvilinear interface crack.
TL;DR: In this paper, a new water-soluble bisbenzenesulfonic acid tetrazolium salt T32 was prepared and its reduction by corticosteroids and ascorbic acid was investigated and utilized for spectrophotometric determinations.
TL;DR: Pieranski and Cladis as mentioned in this paper pointed out that the blue phase space groups derived in our Invited Article [2] are not consistent with the growth forms observed for our BP single crystals.
Abstract: In the preceding Comment [1] Pieranski and Cladis assert that the blue phase space groups derived in our Invited Article [2] are not consistent with the growth forms observed for our BP single crystals (cf. table 3 of [2]). We wish to reply as follows.
TL;DR: Digital implementation of position or path control using high-resolution encoders may require high resolution for control algorithm computations too if the controller state variables carry high-precision absolute position information.
Abstract: Digital implementation of position or path control using high-resolution encoders may require high resolution for control algorithm computations too if the controller state variables carry high-precision absolute position information. If the control algorithm is reformulated in a form in which the controller state is continuously offset according to the possibly nonconstant setpoint, then much less arithmetic wordlength may be sufficient. >
TL;DR: An automated, two-column HPLC-method that can be used routinely to quantify the catecholamines norepinephrine and epinephrine in body fluids is developed.
Abstract: We developed an automated, two-column HPLC-method that can be used routinely to quantify the catecholamines norepinephrine and epinephrine in body fluids. The method is based on a new, laboratory-prepared SEC-HPAC column material, on the application of a microprocessor-controlled column-switching technique, and on the use of an integrated reaction system for postcolumn derivatization and trihydroxyindol-fluorescence monitoring. It allows the direct injection (upto 500 μl) of an appropriate biological fluid and distinguishes on its integrated sample-processing mode, its practicability, its chemoselectivity and-specivity, its detection limit (2 pg), its within- and between-run precision and its speed of analysis.
01 Jan 1988
TL;DR: In this paper, the authors prove a conjecture of the author (1985) for the important case that the space of the possible states of nature is a compact Hausdorff space, thus generalizing a result of Heath and Sudderth (1978) to the countably additive setting.
Abstract: In the present paper we prove a conjecture of the author (1985) for the important case that the space of the possible states of nature is a compact Hausdorff space thus generalizing a result of Heath and Sudderth (1978) to the countably additive setting. No topological assumption is made on the space of observations. We observe that posteriors need not always exist and discuss conditions ensuring the existence of a posterior.