Refine
Has Fulltext
- yes (13121) (remove)
Year of publication
Document Type
- Article (3990)
- Postprint (3216)
- Doctoral Thesis (2501)
- Monograph/Edited Volume (966)
- Review (558)
- Preprint (446)
- Part of Periodical (417)
- Master's Thesis (260)
- Conference Proceeding (245)
- Working Paper (241)
Language
- German (6943)
- English (5878)
- Spanish (80)
- French (75)
- Multiple languages (62)
- Russian (62)
- Hebrew (9)
- Italian (6)
- Portuguese (2)
- Hungarian (1)
Keywords
- Germany (118)
- Deutschland (105)
- Sprachtherapie (77)
- climate change (77)
- Patholinguistik (73)
- patholinguistics (73)
- Nachhaltigkeit (61)
- European Union (59)
- Europäische Union (58)
- Klimawandel (57)
Institute
- Extern (1365)
- MenschenRechtsZentrum (942)
- Institut für Physik und Astronomie (710)
- Institut für Biochemie und Biologie (700)
- Wirtschaftswissenschaften (578)
- Institut für Chemie (551)
- Institut für Mathematik (518)
- Institut für Romanistik (508)
- Institut für Geowissenschaften (505)
- Mathematisch-Naturwissenschaftliche Fakultät (489)
An existence and uniqueness theory is developed for general nonlinear and nonautonomous differential-algebraic equations (DAEs) by exploiting their underlying differential-geometric structure. A DAE is called regular if there is a unique nonautonomous vector field such that the solutions of the DAE and the solutions of the vector field are in one-to-one correspondence. Sufficient conditions for regularity of a DAE are derived in terms of constrained manifolds. Based on this differential-geometric characterization, existence and uniqueness results are stated for regular DAEs. Furthermore, our not ons are compared with techniques frequently used in the literature such as index and solvability. The results are illustrated in detail by means of a simple circuit example.
Executive responsibility for EU policies is by tradition delegated to the member states and their internal administrative bodies. It is therefore of outmost importance that the new Central and East European members have the capacity to administer the acquis communitaire once they are full members of the EU. Based on a survey among current and former top-level decision-makers (ministers), this article argues that although there are significant implementation problems, efficiency gains can be made through administrative reform and not the least education aimed at changing the worldview and knowledge of the individual civil servant. However, there seem to be significant differences in how these countries tackle implementation problems and administrative reform.
Mit dem Ende des Kalten Krieges und der Auflösung der bipolaren Konfrontation trat die Diskussion um eine neue internationale Ordnung auf die politische Agenda. Staaten haben verschiedene Szenarien eingebracht, um für Akzeptanz in der neu geordneten Weltgemeinschaft zu werben. Zu Beginn des 21. Jahrhunderts, insbesondere nach den Anschlägen vom 11. September 2001, hat sich die internationale Lage sehr verändert. Die Etablierung einer neuen Weltordnung ist dringlicher denn je geworden. Aber wie soll diese neue Ordnung aussehen, und wie kann sie Frieden und Entwicklung wirksam voranbringen?
The subject of this paper is the relation of differential-algebraic equations (DAEs) to vector fields on manifolds. For that reason, we introduce the notion of a regular DAE as a DAE to which a vector field uniquely corresponds. Furthermore, a technique is described which yields a family of manifolds for a given DAE. This socalled family of constraint manifolds allows in turn the formulation of sufficient conditions for the regularity of a DAE. and the definition of the index of a regular DAE. We also state a method for the reduction of higher-index DAEs to lowsr-index ones that can be solved without introducing additional constants of integration. Finally, the notion of realizability of a given vector field by a regular DAE is introduced, and it is shown that any vector field can be realized by a regular DAE. Throughout this paper the problem of path-tracing is discussed as an illustration of the mathematical phenomena.
From the Russian perspective, the author describes the danger of a hegemonic US, dominating the world’s fate, weakening the UN and endangering peace. A counterweight to the US domination could be stronger ties between Western Europe and Russia. The rise of the Franco-German-Russian troika has been the only positive effect of the Iraq war. But not all members of the EU seem to recognise the necessity of a „Great Europe” from Reykjavik to Wladiwostok. Especially the new members of NATO and EU are vassals of the US and exhibit strong anti-Russian resentments.
The international community criticises the unilateral actions of the US in Iraq. As a reaction, the United States tries to extend their sphere of influence in other regions. The Brazilian author warns that Brazil in particular could be exposed to this increasing pressure. Therefore Brazil has to take the following five measures: strengthening of Mercosur, a Free Trade Area between the Andean Community and Mercosur, a cooperation agreement with the EU, cooperation with other NICs, and lobbying inside the US.
Technical and physical systems, especially electronic circuits, are frequently modeled as a system of differential and nonlinear implicit equations. In the literature such systems of equations are called differentialalgebraic equations (DAEs). It turns out that the numerical and analytical properties of a DAE depend on an integer called the index of the problem. For example, the well-known BDF method of Gear can be applied, in general, to a DAE only if the index does not exceed one. In this paper we give a geometric interpretation of higherindex DAEs and indicate problems arising in connection with such DAEs by means of several examples.
Poverty, ethnicity and religious fundamentalism are the most pressing problems of the 21st century. According to this Indian author, democratisation on the national and international level is the only way to overcome these problems. One reason for the failing of the international institutions is the insufficient representation of the world community, especially in the UN Security Council. A reform of the United Nations seems indispensable. The war against international terrorism is essential but has to be waged without the differentiation between good and bad terrorists.