Showing papers by "Eindhoven University of Technology published in 1982"
01 Jan 1982
TL;DR: The problem of allocating area to modules at the highest level of a top-down decomposition is treated and a theorem of Schoenberg is applied to obtain a good embedding of the module space into the plane.
Abstract: The problem of allocating area to modules at the highest level of a top-down decomposition is treated in this paper. A theorem of Schoenberg is applied to obtain a good embedding of the module space into the plane. The dutch metric is introduced to transform netlist information - if available - into a distance matrix. This metric is flexible enough to enable the user to steer the design in an interactive environment, and rigorous enough to yield results satisfying optimality criterions. The embedding is used to derive the topology of the floorplan in the form of the structure tree of a slicing structure. To store the partial structure tree during the construction a concise and convenient data structure, the shorthand tree, is introduced. For any aspect ratio of the chip a minimum area floorplan can be generated. The paper also shows how wiring space predictions can be incorporated, how varying degrees of module flexibility can be accounted for, and how fixing bonding pad macros affects the procedure.
333 citations
TL;DR: This work investigates priority rules aimed at minimizing tardiness, emphasizing a “modified duedate rule” which functions effectively in conjunction with internally-set deadlines and which adapts to both tight and loose conditions in the due-dates.
213 citations
TL;DR: In this article, a correlation exists between the reducibility of oxidic MoO3γ-Al2O3 and WO3αγγα-Al 2O3 catalysts prepared by dry and wet impregnation, and the hydrodesulfurization activity of sulfided samples.
199 citations
TL;DR: In this paper, it was shown theoretically that for an isothermal analysis, the relationship of the retention time to the column diameter is determined by the column pressure drop and varies between z 1 for high plate number columns and z ǫ 2 for situations of low pressure drop.
115 citations
TL;DR: In this paper, the appropriateness of an approach based on information integration theory and functional measurement, as a means of predicting consumer response to changes in physical attributes of shopping centres, both from an empirical and methodological point of view, is considered.
Abstract: Timmermans H. (1982) Consumer choice of shopping centre: an information integration approach, Reg. Studies 16, 171–82. This paper is concerned with the relationships between the physical attributes of the retailing system, consumer decision-making and overt behaviour. The appropriateness of an approach, which is based on information integration theory and functional measurement, as a means of predicting consumer response to changes in physical attributes of shopping centres, is considered, both from an empirical and methodological point of view. The results of the empirical study tend to provide general support for the approach. Several methodological issues are raised which deserve further investigation in order to refine the approach.
107 citations
TL;DR: Abyaneh and Fleischmann as mentioned in this paper developed a method of analysis of the overlap of growth centers. But their method is capable of analysing the overlap even when nucleation is two-dimensional (formation of centres on a 2D plane) but growth is threedimensional.
92 citations
TL;DR: The e-tree can be seen as a data structure to guide parallel processing based on sparsity and the earliest and latest admissible time slot for the processing of every pivot may be derived, such that the critical path is not affected.
Abstract: Some new results are presented concerning the pivoting of large systems of linear equations with respect to parallel processing techniques. It will be assumed that the processing of a pivot takes one time slot. The pivoting problem is studied by means of an associated graph model. Given a triangulated graph a set of label classes is established. Class k contains all pivots which may be processed in parallel during the kth time slot. The label classes are used to establish the elimination-tree (e-tree). The e-tree is a spanning tree for the given graph. The critical path in the e-tree indicates the minimum number of time slots necessary to complete the L/U-decomposition. Furthermore, the earliest and latest admissible time slot for the processing of every pivot may be derived, such that the critical path is not affected. The e-tree can be seen as a data structure to guide parallel processing based on sparsity.
78 citations
TL;DR: In this article, a single peak on amine modified silica with acetonitrile was obtained, where the bonded amine groups catalyse the mutarotation in such a way that triethylamine added to eluent has not influence.
76 citations
TL;DR: In this article, the use of the condition number of a problem, as defined by Rice in 1966, is discussed and lower and upper bounds for condition numbers are derived for the eigenvalue, eigenvector, and linear least squares problems.
Abstract: In this paper the use of the condition number of a problem, as defined by Rice in 1966, is discussed. For the eigenvalue, eigenvector, and linear least squares problems either condition numbers according to various norms are determined or lower and upper bounds for them are derived.
75 citations
TL;DR: In this paper, it has been claimed that the addition of manganese oxide, MnO, to an iron catalyst gives a marked increase in the olefin selectivity of iron catalysts.
70 citations
TL;DR: In this paper, the amplitude and phase scintillation measurements at 30 GHz on an 8.2 km line-of-sight path in the Netherlands were presented, and compared favourably with those obtained from weak-scattering theory.
Abstract: The letter summarises results of amplitude and phase scintillation measurements at 30 GHz on an 8.2 km line-of-sight path in the Netherlands. The measured results compare favourably with those obtained from weak-scattering theory.
TL;DR: Statistical multiple access is analysed for a number of independent transmitter-receiver pairs exchanging data packets over a shared mobile-radio channel, resulting in less packet contentions and higher traffic capacity than for the standard Aloha channel.
Abstract: Statistical multiple access is analysed for a number of independent transmitter-receiver pairs exchanging data packets over a shared mobile-radio channel. Rayleigh fading ‘softens’ the channel, resulting in less packet contentions and higher traffic capacity than for the standard Aloha channel.
TL;DR: In this article, the effects of temperature, electrolyte concentration, and electrode material on the maximum value of the electrical current density were studied for both electrodes, and the effect of the concentration of electrolyte was essential.
TL;DR: In this article, the applicability of Kelly's repertory grid methodology to identify the factors influencing consumer choice of shopping centres is discussed. But the main findings of an application of the Repertory Grid methodology are presented, and the implications of the measurement of the determinants of choice behavior and the construction of mathematical models of destination choice are discussed.
Abstract: A common problem of all cognitive-behavioural models of destination choice is that of the identification of factors influencing the behaviour of interest. This paper considers the applicability of Kelly's repertory grid methodology to identify the factors influencing consumer choice of shopping centres. Firstly, some methodological issues in the assessment of the relative importance people attach to certain variables in deciding where to shop are discussed. Secondly, the main findings of an application of the repertory grid methodology are presented. The paper concludes by discussing some implications of the measurement of the determinants of choice behaviour and the construction of mathematical models of destination choice.
01 Jan 1982
TL;DR: In this article, it was shown that the number of non-unique assignments that can be achieved after solving the linear programming relaxation of some types of mixed integer linear assignment problems is bounded.
Abstract: In this paper we will proof that rather tight upper bounds can be given for the number of non-unique assignments that are achieved after solving the linear programming relaxation of some types of mixed integer linear assignment problems. Since in these cases the number of splitted assignments is small a heuristic can be used to reach a practically good and feasible assignment. Moreover the type of proof can be exploited for related problems to investigate whether a linear programming relaxation will yield mainly integer assignments. Key words: mixed integer linear programming, assignment problems, location allocation problems, distribution problems.
TL;DR: In this article, the authors propose an extension of the generally accepted two-stage compaction process to a four-stage process for agglomerated materials, and describe the mechanisms of compaction for two different spray-dried ceramic powders, a wall-tile granulate and a ferrite granulate.
TL;DR: It is shown that singular value decomposition (s.v.d.) is an excellent tool for studying the limit properties of a feasible solution for the inverse problem in electrocardiography and leads to a noise filtering algorithm, which at the same time results in useful data reduction.
Abstract: In the paper it is shown that singular value decomposition (s.v.d.) is an excellent tool for studying the limit properties of a feasible solution for the inverse problem in electrocardiography. When s.v.d. is applied to the transfer matrix, relating equivalent heart sources to the skin potentials, it provides a measure of the observability. In an example presented, a series of orthonormal potential patterns on a pericardial surface are found in an order of decreasing observability. When s.v.d. is applied to a data matrix, consisting of skin potentials as a function of time and position, one finds the normalised principal components both in time and space. An appropriate use of the singular values leads to a noise filtering algorithm, which at the same time results in useful data reduction. Comparison of spatial potential patterns derived from both the transfer matrix and the data matrix may, finally, be used to evaluate the assumptions on the transfer.
TL;DR: In this paper, a simple proof of the pole assignment theorem for systems over a principal ideal domain (and other rings) is given, and an algorithm is presented to solve the problem.
TL;DR: This paper proposes to use an alternative matrix: the Page matrix and shows that this method is better suited for handling the noisy Markov parameters: order testing, noise filtering and realization.
TL;DR: It is shown that in using mathematical models of the standing person to obtained the stabilograms, the resulting statokinesigram is very different from the measured statokinese, and the quantity line-integral calculated from a statokinegram is much smaller when determined from astatokinesigsram corrected by means of the mathematical models.
TL;DR: In this article, it was shown that the best GC-MS interface appears to be no interface at all but rather direct insertion of the column end into the ion source, which can be seen as a form of full sample transfer, no catalysis or adsorption in an interface and increased speed of analysis.
TL;DR: In this article, a numerical analysis of the two-dimensional, time-dependent behavior of a cesium-seeded argon plasma in nonequilibrium MHD generators is presented.
Abstract: A numerical calculation has been developed to describe the two-dimensional, time-dependent behavior of an inhomogeneous plasma in nonequilibrium MHD generators. The development of 'streamers' as typical discharge structures is simulated. A cesium-seeded argon plasma is considered. The numerical conditions used in the calculations are set equal to the experimental conditions used in the Eindhoven shock-tube facility. The elliptic part of the equations is solved by the finite-element method and the hyperbolic part by integration along the characteristic lines. It is found that the current concentrations on each electrode edge grow within microseconds into discharge structures which are concentrated in nonstationary streamers transverse to the gas flow. After they are formed, these streamers are frozen in the gas and are convected downstream at the gas velocity. Inside the streamers the cesium is fully ionized and the electron temperature is in range of 4000-6000 K, and outside the streamers the electron density is about 10 to the 19th and the electron temperature is about 2500 K. These calculated results agree quite well with the experimental ones observed in the Eindhoven shock-tube facility.
TL;DR: In this article, a correlation was established between the intensity of the ESR signal from Mo 3+ and W 3+, in interaction with nickel or cobalt promoter ions at the surface of MoS 2 or WS 2 crystallites, and the catalytic activity for thiophene hydrodesulfurization.
TL;DR: In this article, a model was set up based on the mechanism proposed by Burwell with the active sites being binary Cr 3+ complexes, and the active complex was identified by its ESR signal (δ-signal).
TL;DR: In this article, the authors investigated the properties of reflection and transmission of internal gravity waves incident upon a shear layer containing a critical level and showed that the reflection coefficient is strongly dependent on the place of the critical level in the shear flow.
Abstract: The properties of reflection and transmission of internal gravity waves incident upon a shear layer containing a critical level are investigated. The shear layer is modelled by a hyperbolic tangent profile. In the Boussinesq approximation, the differential equation governing the propagation of these waves can then be transformed into Heun's equation. For large Richardson numbers this equation can be approximated by an equation that has solutions in terms of hypergeometric functions. For these values of the Richardson number the reflection coefficient proves to be strongly dependent on the place of the critical level in the shear flow. If the Doppler-shifted frequency is an odd function of the height difference with respect to the critical level, the reflection and transmission coefficients can be evaluated in closed form.Over-reflection is possible for sufficiently small wavenumbers and Richardson numbers. It is pointed out that over-reflection and over-transmission cannot occur in a stable flow and that resonant over-reflection is not possible in our model.
TL;DR: Comparison of prosthetic valve behaviour with that of the natural aortic valve revealed that the mechanical prostheses mainly close due to the back flow in the early phase of diastole; they close only for 5% of their cross-sectional area during systolic ejection.
TL;DR: In this article, the electric resistance of the bubble containing electrolyte around a small circular electrode was measured as a function of current density, electrode diameter, pressure, temperature and KOH concentration, during both hydrogen and oxygen evolution.
TL;DR: In this paper, a volume-coupling device for isotachophoretic analyses is described in which pre-separation columns with different inner diameters can simply be exchanged (so-called volume coupling).
TL;DR: In this paper, an exact analytical expression for the impact ionisation probability for the main ionisation process in a semiconductor with a Kane-type bandstructure is derived, in a parabolic approximation the integrals involved can be evaluated and the result reduces to the simple relationv====== i�� �(E)=C(E−E�I�� )2Θ(E −E====== i )2
Abstract: An exact analytical expression for the impact ionisation probability for the main ionisation process in a semiconductor with a Kane-type bandstructure is derived. In a parabolic approximation the integrals involved can be evaluated and the result reduces to the simple relationv
i
(E)=C(E−E
i
)2Θ(E−E
i
) whereC is a material constant related to the transition matrix elements. From experimental results on the photo-quantum efficiency we can estimate the value ofC for InSb near 77 K, i.e.ħC ≈ 0.012 eV−1. It is concluded that the impact ionisation probability cannot be described with a unit step function at the threshold energy as was done in many theories on the avalanche effect. The (effective) threshold is smooth and a more detailed description, as derived here, is necessary.
TL;DR: In this paper, the initial stages of the electrocrystallization of zinc from an alkaline electrolyte onto a polycrystalline silver substrate were investigated using the potential step method.
Abstract: The initial stages of the electrocrystallization of zinc from an alkaline electrolyte onto a polycrystalline silver substrate are investigated using the potential step method. In the overpotential region where the reaction is predominantly controlled by charge transfer, computer analysis of the experimental current‐time transients with detailed models of nucleation and growth is possible. This gives information about the kinetics of the reaction and the morphology of the crystal growth. It is concluded that the electrocrystallization of zinc proceeds via nucleation and growth, first of a thin layer of primary centers, having low angle of contact at low overpotentials, and subsequently by a layer, which starts to grow via secondary centers, formed at the sites where the primary centers coalesce.