TY - GEN A1 - Ascher, Uri M. A1 - Chin, Hongsheng A1 - Reich, Sebastian T1 - Stabilization of DAEs and invariant manifolds N2 - Many methods have been proposed for the stabilization of higher index differential-algebraic equations (DAEs). Such methods often involve constraint differentiation and problem stabilization, thus obtaining a stabilized index reduction. A popular method is Baumgarte stabilization, but the choice of parameters to make it robust is unclear in practice. Here we explain why the Baumgarte method may run into trouble. We then show how to improve it. We further develop a unifying theory for stabilization methods which includes many of the various techniques proposed in the literature. Our approach is to (i) consider stabilization of ODEs with invariants, (ii) discretize the stabilizing term in a simple way, generally different from the ODE discretization, and (iii) use orthogonal projections whenever possible. The best methods thus obtained are related to methods of coordinate projection. We discuss them and make concrete algorithmic suggestions. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 030 Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-15625 ER - TY - GEN A1 - Leimkuhler, Benedict A1 - Reich, Sebastian T1 - Symplectic integration of constrained Hamiltonian systems N2 - A Hamiltonian system in potential form (formula in the original abstract) subject to smooth constraints on q can be viewed as a Hamiltonian system on a manifold, but numerical computations must be performed in Rn. In this paper methods which reduce "Hamiltonian differential algebraic equations" to ODEs in Euclidean space are examined. The authors study the construction of canonical parameterizations or local charts as well as methods based on the construction of ODE systems in the space in which the constraint manifold is embedded which preserve the constraint manifold as an invariant manifold. In each case, a Hamiltonian system of ordinary differential equations is produced. The stability of the constraint invariants and the behavior of the original Hamiltonian along solutions are investigated both numerically and analytically. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 032 KW - differential-algebraic equations KW - constrained Hamiltonian systems KW - canonical discretization schemes KW - symplectic methods Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-15653 ER - TY - GEN A1 - Ascher, Uri M. A1 - Chin, Hongsheng A1 - Petzold, Linda R. A1 - Reich, Sebastian T1 - Stabilization of constrained mechanical systems with DAEs and invariant manifolds N2 - Many methods have been proposed for the simulation of constrained mechanical systems. The most obvious of these have mild instabilities and drift problems. Consequently, stabilization techniques have been proposed A popular stabilization method is Baumgarte's technique, but the choice of parameters to make it robust has been unclear in practice. Some of the simulation methods that have been proposed and used in computations are reviewed here, from a stability point of view. This involves concepts of differential-algebraic equation (DAE) and ordinary differential equation (ODE) invariants. An explanation of the difficulties that may be encountered using Baumgarte's method is given, and a discussion of why a further quest for better parameter values for this method will always remain frustrating is presented. It is then shown how Baumgarte's method can be improved. An efficient stabilization technique is proposed, which may employ explicit ODE solvers in case of nonstiff or highly oscillatory problems and which relates to coordinate projection methods. Examples of a two-link planar robotic arm and a squeezing mechanism illustrate the effectiveness of this new stabilization method. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 033 Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-15698 ER - TY - GEN A1 - Köberle, Peter A1 - Laschewsky, André T1 - Hybrid materials from organic polymers and inorganic salts N2 - The prepaparation of amorphous, homogeneous blends of zwitterionic polymers and transition metal salts was investigated. Homogeneous miscibility was achieved in many cases up to equimolar amounts of salt, depending on the anion and cation chosen. Various analytical techniques point to a solid state solution of the inorganic ions in the polymer matrix. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 086 Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-26884 ER - TY - GEN A1 - Schrader, Lutz T1 - Deutschland und die europäische Sicherheitsagenda Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-28999 ER - TY - GEN A1 - Hopf, Diether T1 - Die Schule und die Ausländerkinder N2 - Inhalt: - Überblick und quantitative Verhältnisse - Die Situation in der DDR - Schul- und Unterrichtsprobleme - Ausländerfeindlichkeit - Rückwanderung T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 096 Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-36337 ER - TY - GEN A1 - Hopf, Diether T1 - Kindergarten, Vorschule und Grundschule N2 - Inhalt: - Der Elementarbereich - Die Grundschule - Schüler, Schulen, Klassen - Lehrerinnen und Lehrer - Zur Arbeitsweise der Grundschule - Einschulung, Zeugnisse, «Sitzenbleiben», Schulleistungen und Übergang zur Sekundärschule T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 097 Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-36346 ER - TY - GEN A1 - Selting, Margret T1 - Question intonation revisited : the intonation of conversational questions N2 - Content: 1. Introduction 2. Aim and approach of the present analysis 3. Non-restrictive 'open' conversational questions 4. More restrictive "narrower" questions 5. "Deviant cases" 6. Conclusions T3 - Zweitveröffentlichungen der Universität Potsdam : Philosophische Reihe - 66 Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-43179 ER - TY - JOUR A1 - Lompscher, Joachim T1 - 5. Europäische Konferenz für Lehr- und Lernforschung JF - LLF-Berichte / Universität Potsdam, Zentrum für Lehrerbildung Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-4472 SN - 0945-294X VL - 7 ER - TY - JOUR A1 - Lompscher, Joachim T1 - Learning strategies BT - an essential component of learning activity JF - LLF-Berichte / Universität Potsdam, Zentrum für Lehrerbildung Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-4506 SN - 0945-294X VL - 7 ER - TY - JOUR A1 - Holzkamp, Klaus T1 - Lernen. Subjektwissenschaftliche Grundlegung - Einführung in die Hauptanliegen des Buches JF - LLF-Berichte / Universität Potsdam, Zentrum für Lehrerbildung Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-4525 SN - 0945-294X VL - 8 ER - TY - JOUR A1 - Weinert, Franz E. A1 - Helmke, Andrea T1 - Wie bereichsspezifisch verläuft eine kognitive Entwicklung JF - LLF-Berichte / Universität Potsdam, Zentrum für Lehrerbildung Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-4568 SN - 0945-294X VL - 9 ER - TY - JOUR A1 - Giest, Hartmut T1 - Rinderherdenaufgaben - ein Beispiel für Problemlöseanforderungen in der Grundschule JF - LLF-Berichte / Universität Potsdam, Zentrum für Lehrerbildung Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-4588 SN - 0945-294X VL - 9 ER - TY - JOUR A1 - Lompscher, Joachim T1 - Lernstrategien BT - Zugänge auf der Reflexions- und Handlungsebene JF - LLF-Berichte / Universität Potsdam, Zentrum für Lehrerbildung Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-4597 SN - 0945-294X VL - 9 ER - TY - JOUR A1 - Lompscher, Joachim T1 - 23. Internationaler Kongreß für Angewandte Psychologie JF - LLF-Berichte / Universität Potsdam, Zentrum für Lehrerbildung Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-4605 SN - 0945-294X VL - 9 ER - TY - GEN A1 - Tomassini, Luciano T1 - Eine postmoderne Sicht der internationalen Beziehungen N2 - The dramatic changes in international relations characterized by the terms "Complex Interdependence" and "Segmentary Globalization" call for new explanation. The author considers the post-modern approaches, a critical analysis of which he presents, to be one possibility to do that. In studies of international policy, these post-modern influences are gaining ground in disputes with realistic and neo-realistic approaches, and they can also clearly be felt in Latin America. Tomassini, based on the historic experiences of Latin America, forcefully calls for an active and constructive incorporation of the region into international developments. For that, Latin-American societies have to establish modern, and open political as well as economic systems which are able to meet those challenges. Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10985 ER - TY - GEN A1 - Krüger, Joachim T1 - Zu Gast in Peking : die DDR und die VR China in den 80er Jahren T1 - Visiting Peking : the relationship between the GDR and the People's Republic of China in the 1980s N2 - Taking the visit of Erich Honecker to China as an example, the author analyses the bilateral GDR-Chinese relations in the 1980s. Based on extensive original research, the objectives as well as disappointed hopes are presented. The author reveals that not Honecker played the "Chinese Card", but he himself became part of Chinese politics. At the same time, the contradictory reaction to that visit in Moscow are documented when, with the election of Gorbachev, first signs of a change in Soviet policy toward China were indicated. Jahresabo: 40,00 € (ermäßigt: 25,00 €) Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10999 ER - TY - GEN A1 - Elsenhans, Hartmut T1 - Staat - Wirtschaft - Macht und die Zukunft des internationalen Systems T1 - State, economy, power and the future of the international system N2 - Underlying the importance of revenue the author discusses the future of the international order from the perspective of political economy. The international system will not be a capitalist one. Political conflicts will not be removed by nonviolent market regulations. Weakness of labour force and a dominant role of revenue will further more result in political interventions by nation states. The struggle for revenue to maintain comparative advantages in high-tech-development strengthens state intervention in order to protect domestic market. The failure of the "development state" in the third world and the rising of fundamentalistic tendencies supported by a market-oriented middle class will increase conflicts in those regions. Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-11019 ER - TY - GEN A1 - Derichs, Claudia T1 - Japans Neue Linke : die selbsternannte Avantgarde T1 - Japan’s New Left N2 - Although without providing a systematical comparison, it has become clear that the sects or party-factions of Japan’s New Left movement are by no means merely copies of their counterparts in the West. On the other hand their conduct may not be judged as to be a unique Japanese phenomenon. What they embody is, on the whole, a complex symbiosis of universal and particularly Japanese features, which can be observed in the fields of social behavior, organizational structure, and group dynamics. The particularity of the New Left factions is mostly revealed through the higher intensity of specific features rather than through pecularities found only in Japan. Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-11029 ER - TY - GEN A1 - Jacobsen, Hans-Adolf T1 - Geopolitik im Denken und Handeln Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-11035 ER -