44 research outputs found
Non-elitist Evolutionary Multi-objective Optimizers Revisited
Since around 2000, it has been considered that elitist evolutionary
multi-objective optimization algorithms (EMOAs) always outperform non-elitist
EMOAs. This paper revisits the performance of non-elitist EMOAs for
bi-objective continuous optimization when using an unbounded external archive.
This paper examines the performance of EMOAs with two elitist and one
non-elitist environmental selections. The performance of EMOAs is evaluated on
the bi-objective BBOB problem suite provided by the COCO platform. In contrast
to conventional wisdom, results show that non-elitist EMOAs with particular
crossover methods perform significantly well on the bi-objective BBOB problems
with many decision variables when using the unbounded external archive. This
paper also analyzes the properties of the non-elitist selection.Comment: This is an accepted version of a paper published in the proceedings
of GECCO 201
Structural characterization and sorption of zinc ions on natural and modified zeolite - clinoptilolite.
Development and validation of a laboratory aging method for the accelerated simulation of reclaimed asphalt
The paper presents first results elaborated during the European Research Project Re-road which aims at the development of techniques for increasing the recycling rates of reclaimed asphalt. During service life surface asphalt courses are subjected to aging due to oxidation effects which causes the hardening of the binder and thereby a change in the chemical, physical and mechanical properties of the material. Surface courses often contain highly modified binders as well as special additives for improving the performance characteristics. As these layers inhibit the shortest service lives compared to other road construction layers every year high amounts of reclaimed surface asphalt are available for recycling. The question is raised how the reclaimed asphalt consisting of high quality and costly material components can be recycled for optimal added value. To analyze the asphalt mix service life performance and its recyclability during mix design a laboratory method is developed to simulate the real in-situ aging. First the effects of site aging on the binder and asphalt characteristics are presented. Three laboratory aging methods are discussed which aim the accelerated aging which meets similar property changes as site aging. At last the effects of two different laboratory aging methods on the same SMA mixture are compared
Anomalous scattering in structural chemistry and biology
The uses of X-ray anomalous scattering in crystal structure analysis have undergone a major expansion due to the refinement and ease of availability of the necessary X-ray instrumentation and methods. The structural chemistry and biology fields span a similar suite of technical needs but with widely differing molecular systems. The innate synergies between the two research fields brought two of the authors (JRH and VK) together at an Erice Summer School on Synchrotron Radiation in Crystallography in 1985 and took them into a collaboration spanning already 20 years. The authors’ wide perspectives are therefore, if not unique, perhaps rather rare. Thus the breadth of coverage of this review is unusual. However, there are two excellent books on anomalous scattering and its uses that have been published covering the periods up to 1975 and 1994 [S. Ramaseshan, S.C. Abrahams (Eds). Anomalous Scattering, Munksgaard, Copenhagen (1975); G. Materlik, C.J. Sparks, K. Fischer (Eds). Resonant Anomalous X-ray Scattering: Theory and Applications, North Holland, Amsterdam (1994)]. As the number of examples of applications in structural biology are now so many it has only been possible to select some illustrative examples but with surveys of trends. In addition though, the develop- ment of the methodologies is described in more detail. The structural chemistry applications in, for example, microporous materials, superconductors and magnetic materials is expanding fast but still at a stage where we could attempt to provide a detailed coverage of results, which we have done. Anomalous scattering results on locating metal atoms can also be compared with other technique results and so sections on X-ray Absorption Spectroscopy (XAS), Diffraction Anomalous Fine Structure (DAFS), neutron diffraction and Nuclear Magnetic Resonance (NMR) applications are described where they relate to metal atom location and local structure. Finally anomalous scattering has also been very useful to help develop the modern synchrotron Laue method for quantitative crystal structure analysis, which is also briefly described