Arbeiten des Institutes für Thermodynamik und Verbrennungskraftmaschinen an der Technischen und Montanistischen Hochschule Graz-Leoben in Graz

Ohne Zusammenfassung     

Neural networks, error-correcting codes, and polynomials over thebinary n-cube

Several ways of relating the concept of error-correcting codes to the concept of neural networks are presented. Performing maximum-likelihood decoding in a linear block error-correcting code is shown to be equivalent to finding a global maximum of the energy function of a certain neural network. Given a linear block code, a neural network can be constructed in such a way that every codeword corresponds to a local maximum. The connection between maximization of polynomials over the n-cube and error-correcting codes is also investigated; the results suggest that decoding techniques can be a useful tool for solving such maximization problems. The results are generalized to both nonbinary and nonlinear codes     

Vorgänge in Einspritzsystemen schnellaufender Dieselmotoren

Forschung im Ingenieurwesen - Die Schwingungsnatur der Vorgänge innerhalb des aus Einspritzpumpe, Druckleitung und Düse bestehenden Einspritzsystemes der kompressorlosen Dieselmaschine...     

Combinatorial Properties for Traceability Codes Using Error Correcting Codes

In this correspondence, the combinatorial properties of traceability codes constructed from error-correcting codes are studied. Necessary and sufficient conditions for traceability codes constructed from maximum-distance separable (MDS) codes are provided. The known sufficient conditions for a traceability code are proven to be also necessary for linear MDS codes     

A (16, 9, 6, 5, 4) error-correcting DC free block code

A (2n, k, l, c, d) DC free binary block code is a code of length 2n, constant weight n, 2^k codewords, maximum runlength of a symbol l , maximum accumulated charge c, and minimum distance d . The purpose of this code is to achieve DC freeness and error correction at the same time. The goal is to keep the rate k/2 n and d large and l and c small. Of course, these are conflicting goals. H.C. Ferreira (IEEE Trans. Magn., vol.MAG-20, no.5, p.881-3, 1984) presented a (16, 8, 8, 5, 4) DC free code. Here, a (16, 9, 6, 5, 4) DC free code is presented. Easy encoding and decoding algorithms are also given     

On lowest density MDS codes

Let F_q denote the finite field GF(q) and let h be a positive integer. MDS (maximum distance separable) codes over the symbol alphabet F_q^b are considered that are linear over F _q and have sparse (“low-density”) parity-check and generator matrices over F_q that are systematic over F_q^b. Lower bounds are presented on the number of nonzero elements in any systematic parity-check or generator matrix of an F_q-linear MDS code over F_q^b, along with upper bounds on the length of any MDS code that attains those lower bounds. A construction is presented that achieves those bounds for certain redundancy values. The building block of the construction is a set of sparse nonsingular matrices over F_q whose pairwise differences are also nonsingular. Bounds and constructions are presented also for the case where the systematic condition on the parity-check and generator matrices is relaxed to be over F_q, rather than over F_q^b     

Zur dynamik des katalytischen festbettreaktors bei katalysator-desaktivierung—I.

The influence of catalyst deactivation on the dynamic behaviour of a catalytic fixed-bed-reactor is investigated. Using the spatially one-dimensional two-phase-model and an additional differential equation for the activity, profiles of temperature and activity are shown and compared to experimental results. It turns out that, due to deactivation, moving reaction zones can occur even at constant inlet conditions and that, in case of rapid deactivation, serious overheating of the reactor may result.     

The Electron Capture ^{163}Ho Experiment ECHo

The determination of the absolute scale of the neutrino masses is one of the most challenging present questions in particle physics. The most stringent limit, \(m(\bar{\nu }_{\mathrm {e}})< 2\)  eV, was achieved for the electron anti-neutrino mass. Different approaches are followed to reach a sensitivity on neutrino masses in the sub-eV range. Among them, experiments exploring the beta decay or electron capture of suitable nuclides can provide information on the electron neutrino mass value. We present the electron capture \(^{163}\) Ho experiment ECHo, which aims to investigate the electron neutrino mass in the sub-eV range by means of the analysis of the calorimetrically measured energy spectrum following electron capture in \(^{163}\) Ho. A high precision and high statistics spectrum will be measured with arrays of metallic magnetic calorimeters. We discuss some of the essential aspects of ECHo to reach the proposed sensitivity: detector optimization and performance, multiplexed readout, \(^{163}\) Ho source production and purification, as well as a precise theoretical and experimental parameterization of the calorimetric EC spectrum including in particular the value of \(Q_{\mathrm {EC}}\) . We present preliminary results obtained with a first prototype of single channel detectors as well as a first 64-pixel chip with integrated micro-wave SQUID multiplexer, which will already allow to investigate \(m(\nu _{\mathrm {e}})\) in the eV range.