Werner Hansmann

Mechanical design in spines of diadematoid echinoids (Echinodermata, Echinoidea)

SummaryThe long and slender spines of Diadema are highly flexible, although their skeleton consists mainly of CaCO3 and behaves optically like a single monocrystal of calcite. The flexibility is due to the shape of the spine skeleton as well as to the material properties of the echinoderm calcite.The spine skeletons are hollow beams consisting of radial wedges or septs. The shape of the septs shows a broad base situated at the periphery of the cross section, producing a high load-bearing capacity with minimum weight. Furthermore, material is concentrated at the base of the spine in such a way that the strain of the structure is kept constant along the axis. The septs are connected with one another by a few transverse bars positioned as closely as possible to the axis. The load-bearing parts of the septs are free. They have small diameters similar to flexible glass fibres. The stiff spines of other echinoids are also mainly built by radial wedges, but the spaces in between are closely filled with transverse bars. On the surface of stiff spines there are low grooves between the septs. The echinoid spines are covered with an epithelium which shows a basiepithelial nerve plexus. In the stiff spines this plexus forms cords which lie protected within the superficial grooves mentioned. In the flexible spines of Diadema the cords are deeply sunken in the spaces between the septs. In this manner the nerve cords are largely free from the tensile stresses to which the spines surface is exposed.The flexible spines were used to determine the material properties of echinoderm calcite. Youngs modulus was determined for fresh (live) spines, dry spines, and cleaned spine skeletons. Fresh spines show the highest elasticity, and their Youngs modulus is significantly below the Youngs modulus of the other test groups. The echinoderm calcite does not show the cleavage planes of mineral calcite, and probably this feature contributes to the high flexibility of echinoderm calcite.

The beginning computer graphics course in computer science

A report from the working group on computer graphics in computer science 2004 SIGGRAPH/Eurographics Computer Graphics Education workshop, Zhejiang University, Hangzhou, China, June 2-6, 2004.

Computer graphics curricula for a wide range of disciplines

Abstract The present paper discusses the position of computer graphics education within the framework of computer science education at Hamburg University. Starting from a survey of the current situation, where education in advanced areas of computer graphics has been influenced mainly by the scientific backgrounds of the persons who happen to be teaching computer graphics, a new set of curricula is being suggested which aims individually at the different possible target groups of computer graphics education at Hamburg University.

A survey of computer graphics education at german universities

Abstract To obtain an insight into the current state of the education in computer graphics at institutions of academic education in Germany, a survey was carried out in the spring of 1996. The target group for this survey involved teachers of computer graphics at German universities (including technical universities). The present contribution sets forth the topics on which information was sought, and summarizes the resulting information obtained from the persons addressed by this inquiry.

A survey of computer graphics in art education in germany

Abstract Computer graphics has become a well established discipline and a subject of academic education in most computer science curricula. Does this fact already show any impact on the curricula of other disciplines? Art education for instance could involve a considerable amount of computer graphics. A survey was conducted in the spring of 1996 in order to obtain a first insight into the current state of computer graphics related education at art schools and art departments of universities in Germany. The present contribution sets forth the topics on which information was sought, and summarizes the resulting information obtained from the persons addressed by this inquiry.

Editorial for the ISC’09 Scientific Day Proceedings

The International Supercomputing Conference started in 1986 as the “Supercomputer Seminar” organized by Prof. Hans Meuer, then director of the computer center and professor for computer science at the University of Mannheim (Germany). Since these early days the annual conference became a major international event in the HPC community. As the conference grew bigger, it moved from Mannheim over Heidelberg and Dresden to Hamburg. In 2009 we expect more than 1,500 participants who will attend the exhibition and the various scientific and technical sessions. Over the years we decided to strengthen the scientific part of the conference and present selected talks on relevant research results in the field of HPC. These scientific sessions started in 2007 and preceded the conference. Slides and accompanying papers were made available via the conference web site. For 2009 we changed this concept and give the scientific part of the conference a higher ranking and visibility. The scientific sessions now merge into the Scientific Day, which is an integral part of the conference. The Scientific Day is scheduled in the afternoon of the first day of the conference. The call for participation was issued in winter 2008 and invited researchers and developers to submit latest results of their work as full research papers to the program committee of the Scientific Day. We solicited contributions in the fields of applications, system architecture, and large-scale system

Auswertung von Testbolusdaten

Bei der Kontrastmittel-Computertomographie erhalt die Untersuchungsplanung durch das Problem der zeitlichen Abstimmung von Injektion und Aufnahmezeitraum eine verstarkte Bedeutung. Zur Planungsunterstutzung wurde ein Verfahren implementiert, das anhand einer Testbol us -Sequenz die zu erwartenden Dichte-Werte einer Region fur beliebige Injektionseinstellungen und Scanintervalle simuliert. Die zur Planung erzeugten Testmessungen entsprechen einer dynamischen Untersuchung. Daher wurde ein Verfahren entwickelt, mit dem Herzfunktionsparameter aus der erzeugten Testbolus -Sequenz abgeleitet werden konnen. Die vorgestellten Verfahren wurden jeweils anhand der Auswertung aus Testbolus -Sequenz und CT-Untersuchung bestehender Datensatze getestet. Der Vergleich der simulierten mit den gemessenen Zeit-Dichte-Kurven und die Gegenuberstellung der aus Testbolus Sequenz und Untersuchungsdaten ermittelten Herzfunktionsparameter zeigen vielversprechende Ergebnisse.

Germany: computer graphics in computer science and art education

The vitality of computer graphics education in Germany persists. The last general inquiry on computer graphics education was made in 1993 by the Special Interest Group on Computer Graphics within the German Society of Computer Science (Gesellschaft für Informatik (GI)) [2, 3, 4]. Since then, the number of institutions at German universities that offer an education in computer graphics (generally professors appointed for teaching and research in the field) has risen considerably. While the 1993 survey came up with 29 individuals at 26 universities, the current situation shows 40 at 33 universities.In general, the fundamental education in computer graphics at an academic level (i.e. discursive dealing with methods of both computer graphics and various related fields) is carried out at universities, usually as part of the curricula in Computer Science Departments. Education in computer graphics, which is primarily application oriented, can be obtained in Engineering and Art Departments of universities, at technical schools (Fachhochschulen) and art schools (Hochschulen für Kunst). The previously mentioned investigation of 1993 focused on computer graphics education at universities and technical schools. The recent surveys were conducted to determine the current situation of computer graphics as a subject of academic education per se, as well as a means and tool for art education.