233 research outputs found
Cellular automaton for the fracture of disordered media
We study numerically the growth of a crack in an elastic medium under the
influence of a travelling shockwave. We describe the implementation of a fast
algorithm which is perfectly suited for a data parallel computer. Using large
scale simulations on the Connection Machine we generate cracks with more than
10000 sites on a lattice. We show that the
resulting patterns are fractal with a fractal dimension that depends on the
chosen breaking criterion and varies between and
Comment: 9 pages, 6 figures (3 included), plain TeX (using vanilla.sty,
epsf.tex), HLRZ-preprint 46/9
Power law tail in the radial growth probability distribution for DLA
Using both analytic and numerical methods, we study the radial growth
probability distribution for large scale off lattice diffusion limited
aggregation (DLA) clusters. If the form of is a Gaussian, we show
analytically that the width of the distribution {\it can not} scale as
the radius of gyration of the cluster. We generate about clusters
of masses up to particles, and calculate the distribution by
sending further random walkers for each cluster. We give strong support
that the calculated distribution has a power law tail in the interior () of the cluster, and can be described by a scaling Ansatz , where denotes
some scaling function which is centered around zero and has a width of order
unity. The exponent is determined to be , which is now
substantially smaller than values measured earlier. We show, by including the
power-law tail, that the width {\it can} scale as , if .Comment: 11 pages, LaTeX, 5 figures not included, HLRZ preprint-29/9
Improving Informational Bases of Performance Measurement with Grey Relation Analysis
Performance measurement (PM) needs objective empirical data with causal relevance in order to steer and control financial performance generation. In business practice, there is often a lack of such objective data. A surrogate might be collected subjectively based on data generated by questioning corporate experts. Such an involvement of subjects can rapidly lead to an immense extent of data that (partially) imply incomplete information. To handle this imperfection of data, the Grey systems theory (GST) and especially its element, the Grey relation analysis (GRA), seem to be methodologies able to improve informational bases for PM purposes. Therefore, GRA is able to reveal those performance indicators that considerably influence the corporate financial performance, the key performance indicators. GRA is able to supply valid results with only four data points of a time series. Hence, the GST provides an improvement of the PM framework in situations of incomplete information, which is demonstrated in the following
Performance Management by Causal Mapping: An Application Field of Knowledge Management
As implied by the performance management (PM) concept, modern corporate management has to focus on cause-and-effect relationships underlying a firm´s financial performance generation. To determine the causes of financially desirable effects, subject-bound experiences and knowledge of employees, called tacit knowledge, should be realised. For this, knowledge management (KM) offers various elicitation techniques to reveal corporate-specific success factors (SFs) of financial performance generation from the corporate experts´ implicit knowledge. The identified factors have to be organised within a network of cause-and-effect relationships. In this framework, PM can apply the instrument of mapping to structure the individually revealed knowledge, to aggregate and visualise it for the entire company. For a valid representation of the causal relationships, the subjective bias arising within the mentioned process has to be minimised. In the literature, a variety of mapping methods can be found that differ in their approaches and their level of significance. As such a method, causal mapping will be presented in this paper. For providing intersubjectivity, the decision-making trail and evaluation laboratory (DEMATEL) as a multi-criteria approach will be debated in the context of mapping as a research field
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