TY - CONF AU - Krauter, Stefan AU - Hanitsch, Rolf AU - Diwisch, R. AU - Diwisch, N. ID - 8087 TI - Measuring the Heat–Transfer Coefficient of PV-Modules ER - TY - CONF AU - Krauter, Stefan AU - Hanitsch, Rolf ID - 8088 T2 - Proceedings of the 11th European Photovoltaic Solar Energy Conference and Exhibition, Montreux (Schweiz), 12.–16. Oktober 1992, S. 1351–1354 TI - Performance of a Partly Structured Surface at a PV-Module ER - TY - GEN AU - Engels, Gregor ID - 8189 TI - Visual Specifications of Conceptual Database Schemata (Abstract) ER - TY - CONF AB - This experience report describes the development of the CASE environment CADDY Computer-Aided Design of non-traditional Databases 1 which oflers an integrated set of tools for specifying, analyzing, and prototyping a database application on a conceptual level. This environment was designed and implemented during the last four years at Braunschweig Technical University (Germany). The process of developing this environment consisted of a sequence of development steps, where each step corresponded to (at least) one of five main tasks. The intention of this report is to describe these five tasks. At the end, we will critically reflect on the achieved results and solved problems, but also on still open questions of the CADDY environment. AU - Engels, Gregor AU - Löhr-Richter, Perdita ID - 8260 T2 - Proceedings of the Fifth International Workshop on Computer-Aided Software Engineering (CASE 1992), Montreal (Canada) TI - CADDY: A Highly Integrated Environment to Support Conceptual Database Design ER - TY - CONF AU - Engels, Gregor AU - Groenewegen, Luuk ID - 8261 T2 - Proceedings of the Second European Workshop on Software Process Technology (EWSPT 92), Trondheim, Norway TI - Specification of Coordinated Behaviour in the Software Development Process VL - 635 ER - TY - JOUR AB - This paper presents the high-level query language SQL/EER for an extended Entity-Relationship model (EER model). SQL/EER directly supports all the concepts of the EER model and takes into account well-known features that are integral part of contemporary query languages, e.g. arithmetic and aggregate functions. In contrast to usual descriptions of query languages, we give SQL/EER a complete formal specification of syntax and sematics. This syntax is defined by using an attribute grammar which fixes the context-free structure and the context-sensitive rules. The operational semantics is defined by formally translating SQL/EER queries into queries of an existing, semantically well-defined calculus. The attribute grammar is extended to cover this translation, too. The query language SQL/EER is used in a database design environment. In this context, the formal specification of its syntax and the semantics has been used to implement a syntax-directed editor and a query interpreter for SQL/EER. AU - Hohenstein, Uwe AU - Engels, Gregor ID - 7408 IS - 3 JF - Information Systems TI - SQL/EER - Syntax and Semantics of an Entity-Relationship-Based Query Language VL - 17 ER - TY - JOUR AB - The conceptual modeling approach of the IPSEN (Integrated Project Support Environment) project for building highly integrated environments is based on using attributed graphs to model and implement arbitrary object structures, in particular all kinds of software documents and their relationships. A language based on graph grammars, called PROGRESS (Programmed Graph REwriting SyStems), and a suitable method for the application of this language, called graph grammar engineering, have been developed over the last ten years. This language and method are being extensively used for specifying the complex graph structures of internal document representations as well as for specifying the functionality of all tools (editors, browsers, analyzers, debuggers) working on these internal representations. This paper explains the language and the method for applying the language based on a pragmatic nontrivial example of a software production process and its corresponding documents. In particular, it is shown why and how a graph grammar-based strongly typed language is perfectly suitable to formally specify highly integrated software tools. In addition, it is shown that the implementation of these tools (i.e., an environment composed of these tools) is systematically being derived from the formal specifications. AU - Engels, Gregor AU - Lewerentz, Claus AU - Nagl, Manfred AU - Schäfer, Wilhelm AU - Schürr, Andy ID - 7409 IS - 2 JF - ACM Transactions on Software Engineering and Methodology (TOSEM) TI - Building Integrated Software Development Environments, Part I: Tool Specification VL - 1 ER - TY - JOUR AB - In this paper, we motivate and present a data model for conceptual design of structural and behavioural aspects of databases. We follow an object centered design paradigm in the spirit of semantic data models. The specification of structural aspects is divided into modelling of object structures and modelling of data types used for describing object properties. The specification of object structures is based on an Extended Entity--Relationship (EER) model. The specification of behavioural aspects is divided into the modelling of admissible database state evolutions by means of temporal integrity constraints and the formulation of database (trans)actions. The central link for integrating these design components is a descriptive logic--based query language for the EER model. The logic part of this language is the basis for static constraints and descriptive action specifications by means of pre- and postconditions. A temporal extension of this logic is the specification language for temporal integrity constraints. We emphasize that the various aspects of a database application are specified using several appropriate, but yet compatible formalisms, which are integrated by a unifying common semantic. AU - Engels, Gregor AU - Gogolla, Martin AU - Hohenstein, Uwe AU - Hülsmann, Klaus AU - Löhr-Richter, Perdita AU - Saake, Gunter AU - Ehrich, Hans-Dietrich ID - 7410 IS - 2 JF - Data & Knowledge Engineering TI - Conceptual Modelling of Database Applications Using an Extended ER Model VL - 9 ER - TY - JOUR AU - Krimphove, Dieter ID - 1650 IS - Juni-Heft JF - Recht der Landwirtschaft TI - Die Bedeutung des Produkthaftungsrechtes für die Landwirtschaft ER - TY - JOUR AU - Krimphove, Dieter ID - 1651 IS - Oktober-Heft JF - Recht der Landwirtschaft TI - Die eingetragene Genossenschaft als Gesellschafts- und Unternehmensform ER - TY - JOUR AU - Krimphove, Dieter ID - 1652 IS - 11 JF - Sächsisches Genossenschaftsblatt TI - Arbeitsrechtliche Aspekte der Verschmelzung von Genossenschaften ER - TY - JOUR AU - Krimphove, Dieter ID - 1653 IS - 12 JF - Europäisches Wirtschafts- & Steuerrrecht TI - Der Begriff des "Europäischen Marktes" im Lichte der Rechtssprechung des Europäischen Gerichtshofes und der Entscheidungspraxis der Kommission der Europäischen Gemeinschaft ER - TY - CHAP AU - Dellnitz, Michael AU - Golubitsky, Martin AU - Melbourne, Ian ID - 16546 SN - 9783034875387 T2 - Bifurcation and Symmetry TI - Mechanisms of Symmetry Creation ER - TY - CHAP AU - Dellnitz, Michael AU - Marsden, Jerrold E. AU - Melbourne, Ian AU - Scheurle, Jürgen ID - 16547 SN - 9783034875387 T2 - Bifurcation and Symmetry TI - Generic Bifurcations of Pendula ER - TY - JOUR AU - Dellnitz, M AU - Melbourne, I AU - Marsden, J E ID - 16548 JF - Nonlinearity SN - 0951-7715 TI - Generic bifurcation of Hamiltonian vector fields with symmetry ER - TY - CHAP AU - Dietzfelbinger, Martin AU - Meyer auf der Heide, Friedhelm ID - 16733 SN - 0302-9743 T2 - Data structures and efficient algorithms TI - High performance universal hashing, with applications to shared memory simulations ER - TY - CHAP AU - Meyer auf der Heide, Friedhelm ID - 16734 SN - 0302-9743 T2 - Lecture Notes in Computer Science TI - Hashing strategies for simulating shared memory on distributed memory machines ER - TY - CHAP AU - Meyer auf der Heide, Friedhelm AU - Pham, Hieu Thien ID - 16735 SN - 0302-9743 T2 - STACS 92 TI - On the performance of networks with multiple busses ER - TY - CONF AU - Karp, Richard M. AU - Luby, Michael AU - Meyer auf der Heide, Friedhelm ID - 16736 SN - 0897915119 T2 - Proceedings of the twenty-fourth annual ACM symposium on Theory of computing - STOC '92 TI - Efficient PRAM simulation on a distributed memory machine ER - TY - CHAP AU - Dietzfelbinger, Martin AU - Meyer auf der Heide, Friedhelm ID - 16737 SN - 1615-4584 T2 - TEUBNER-TEXTE zur Informatik TI - Dynamic Hashing in Real Time ER - TY - JOUR AU - Dellnitz, Michael ID - 17012 IS - 3 JF - IMA Journal of Numerical Analysis TI - Computational bifurcation of periodic solutions in systems with symmetry VL - 12 ER - TY - CHAP AU - Krimphove, Dieter ED - Ohlmeyer, Dietrich ED - Philipowski, Rüdiger ID - 1717 T2 - Die Verschmelzung von Genossenschaften - insbesondere von Kreditgenossenschaften TI - Die Auswirkungen des Betriebsüberganges nach § 613 a BGB auf die Rechte der Arbeitnehmer ER - TY - CHAP AU - Oevel, Gudrun AU - Wagner, M. ID - 17177 T2 - Frauen in natur- und ingenieurwissenschaftlichen Berufen TI - Förderung von Studentinnen im Grundstudium VL - 17 ER - TY - CONF AU - Aubert, Xavier L. AU - Ney, Hermann AU - Haeb-Umbach, Reinhold ID - 11719 T2 - DRAPA Speech Workshop TI - The Philips Research System for Continuous-Speech Recognition: Overview and Evaluation on the DRAPA RM Task ER - TY - CONF AU - Geller, Dieter AU - Haeb-Umbach, Reinhold AU - Ney, Hermann ID - 11769 T2 - ESCA Workshop on Speech Recognition in Adverse Conditions, Cannes-Mandelieu TI - Improvements in Speech Recognition for Voice Dialling in the Car Environment ER - TY - JOUR AB - The problem of trellis coding for multilevel baseband transmission over partial response channels with transfer polynomials of the form (1+or-D/sup N/) is addressed. The novel method presented here accounts for the channel memory by using multidimensional signal sets and partitioning the signal set present at the noiseless channel output. It is shown that this coding technique can be viewed as a generalization of a well-known procedure for binary signaling: the concatenation of convolutional codes and inner block codes that are tuned to the channel polynomial. It results in high coding gains with moderate complexity if some bandwidth expansion is accepted. AU - Haeb-Umbach, Reinhold ID - 11782 JF - IEEE Transactions on Communications TI - A modified trellis coding technique for partial response channels ER - TY - JOUR AB - The authors present conditions on the error sequences between channel input sequences which guarantee certain lower bounds on the free Euclidian distance at the output of a partial-response (PR) class I or II channel. From these expressions, trellis codes are derived which improve performance of binary signaling over noisy PR channels with reduced complexity maximum-likelihood sequence detection. They are shown to be compatible with the input restriction caused by the magnetooptical resonant coil direct overwrite recording scheme. The codes achieve high signal-to-noise ratio coding gains of 3 dB (on PR class I) and 2.2 dB (on PR class II) with rates as close to, but strictly less than, the capacity of the initial input restriction as desired. The performance of these codes is analyzed with an optical channel simulation system which shows that one code has the rare but highly desirable property that its maximum-likelihood sequence detector (MLSD) is less complex than the MLSD of the reference system and still achieves an error rate performance gain of 1.8 dB AU - Haeb-Umbach, Reinhold AU - Lynch, Robert ID - 11792 JF - IEEE Journal on Selected Areas in Communications TI - Trellis codes for partial-response magnetooptical direct overwrite recording ER - TY - CONF AB - The interaction of linear discriminant analysis (LDA) and a modeling approach using continuous Laplacian mixture density HMM is studied experimentally. The largest improvements in speech recognition could be obtained when the classes for the LDA transform were defined to be sub-phone units. On a 12000 word German recognition task with small overlap between training and test vocabulary a reduction in error rate by one-fifth was achieved compared to the case without LDA. On the development set of the DARPA RM1 task the error rate was reduced by one-third. For the DARPA speaker-dependent no-grammar case, the error rate averaged over 12 speakers was 9.9%. This was achieved with a recognizer using LDA and a set of only 47 Viterbi-trained context-independent phonemes. AU - Haeb-Umbach, Reinhold AU - Ney, Hermann ID - 11797 T2 - ICASSP, San Francisco TI - Linear Discriminant Analysis for Improved Large Vocabulary Continuous Speech Recognition ER - TY - CONF AB - This paper describes the improvements in a time synchronous beam search strategy for a 10000-word continuous speech recognition task. The improvements are based on two measures: a tree-organization of the pronunciation lexicon and a novel look-ahead technique at the phoneme level, both of which interact directly with the detailed search at the state levels of the phoneme models. Experimental tests were performed for four speakers on a 12306-word task. As a result of the above measures, the overall search effort was reduced by a factor of 17 without a loss in recognition accuracy. AU - Ney, Hermann AU - Haeb-Umbach, Reinhold AU - Tran, B. H. AU - Oerder, Martin ID - 11877 T2 - ICASSP, San Francisco TI - Improvements in Beam Search for 10,000-Word-Continuous Speech Recognition ER - TY - GEN AU - Hellebrand, Sybille AU - Tarnick, Steffen AU - Rajski, Janusz AU - Courtois, Bernard ID - 13023 TI - Generation of Vector Patterns through Reseeding of Multiple-Polynomial LFSRs ER - TY - CONF AU - Domik, Gitta O AU - Mickus-Miceli, Kristina D ED - Worrall, D.M. ED - Biemesderfer, Ch. ID - 14997 T2 - Astronomical Data Analysis Software and Systems I TI - Software design and development in a scientific environment: lessons learned during the development of STAR, an astrophysical analysis and visualization package VL - 25 ER - TY - CONF AU - Domik, Gitta ID - 15042 T2 - European Southern Observatory Conference and Workshop Proceedings TI - Visualization of Multi-dimensional Arrays in Astronomy VL - 43 ER - TY - CONF AU - Mickus-Miceli, KD AU - Domik, G ID - 15252 T2 - Symposium on Intelligent Scientific Computation, American Association for Artificial Intelligence (AAAI), Fall 1992 Symposium Series, Cambridge MA, October TI - An Enriched Framework for Multidisciplinary Data Analysis ER - TY - BOOK AU - Krimphove, Dieter ID - 1600 TI - Europäische Fusionskontrolle ER - TY - BOOK AU - Krimphove, Dieter ID - 1601 TI - Anlageberatung Das System der zivilrechtlichen Haftung von Kreditinstituten ER - TY - GEN AU - Hellebrand, Sybille AU - Tarnick, Steffen AU - Rajski, Janusz AU - Courtois, Bernard ID - 13076 KW - WORKSHOP TI - Generation of Vector Patterns through Reseeding of Multiple-Polynomial LFSRs ER - TY - GEN AU - Hellebrand, Sybille AU - Tarnick, Steffen AU - Rajski, Janusz AU - Courtois, Bernard ID - 13080 KW - WORKSHOP TI - Generation of Vector Patterns through Reseeding of Multiple-Polynomial LFSRs ER - TY - CONF AU - Steffen, Eckhard ED - Börger, E. ID - 10201 T2 - Computer Science Logic TI - Complexity results for the default- and autoepistemic logic VL - 626 ER - TY - CONF AU - Ginthör, Robert AU - Platzner, Marco AU - Weiss, Reinhold ID - 13465 T2 - Proceedings of the 1st Austrian-Hungarian Workshop on Transputer Applications TI - Experimental Results to Interprocessor Communication in Distributed Transputer-Systems ER - TY - CONF AU - Fröhleke, Norbert AU - Kunze, Jürgen AU - Fiedler, A. AU - Grotstollen, Horst ID - 30013 T2 - APEC '92 Seventh Annual Applied Power Electronics Conference and Exposition TI - Contribution to the AC-analysis of resonant converters; analysis of the series-parallel resonant converter including effects of parasitics and lossless snubbers for optimized design ER - TY - CONF AU - Kunze, Jürgen AU - Fröhleke, Norbert AU - Grotstollen, Horst AU - Margaritis, Basile AU - Locken, F. ID - 30014 T2 - Conference Record of the 1992 IEEE Industry Applications Society Annual Meeting TI - Resonant power supply for barrier discharge UV-excimer sources ER - TY - JOUR AB - Rezensionen: MR 93d:01046 (Charles F. Kielkopf); Zbl. Math. 756.01034 (I. Grattan-Guinness). AU - Peckhaus, Volker ID - 17474 JF - Berichte zur Wissenschaftsgeschichte TI - Hilbert, Zermelo und die Institutionalisierung der mathematischen Logik in Deutschland VL - 15 ER - TY - GEN AU - Peckhaus, Volker ED - Binder, Christa ID - 17828 T2 - III. Österreichisches Symposion zur Geschichte der Mathematik. Neuhofen an der Ybbs, 8. bis 14. November 1992. Umwege, Abschneider und Sackgassen ... über Abweichungen vom „normalen“ Gang der Entwicklung. Kurzfassungen der Vorträge TI - Wozu Algebra der Logik? Zum Lebenswerk von Ernst Schröder [Abstract] ER - TY - GEN AU - Peckhaus, Volker ID - 17826 T2 - Deutsche Mathematiker-Vereinigung. Jahrestagung 13.–18.9.1992 in Berlin. Vortragsauszüge TI - Arithmetik — Logik — absolute Algebra. E. Schröders Suche nach einer universalen Theorie der Verknüpfungen [Abstract] ER - TY - THES AU - Fröhleke, Norbert ID - 30017 SN - 978-3-86111-142-9 TI - Topologien und Schalterkonzepte für Schaltnetzteile hoher Leistung bei geringer Ausgangsspannung ER - TY - THES AU - Wang, Yongfan ID - 30018 SN - 978-3-86111-155-9 TI - Pulswechselrichtergespeiste Drehstromantriebe unter Berücksichtigung des Stromlückens ER - TY - JOUR AU - Wunderlich, Hans-Joachim AU - Hellebrand, Sybille ID - 13017 IS - 1 JF - IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems (TCAD) TI - The Pseudoexhaustive Test of Sequential Circuits VL - 11 ER - TY - CONF AU - Hellebrand, Sybille AU - Tarnick, Steffen AU - Rajski, Janusz AU - Courtois, Bernard ID - 13016 T2 - IEEE International Test Conference (ITC'92) TI - Generation of Vector Patterns through Reseeding of Multiple-Polynomial Linear Feedback Shift Registers ER - TY - GEN AU - Buhl, Engelbert AU - Buhl, Heike M. ID - 32459 TI - Die Aktualgenese von Raummodellen und ihr Einfluß auf die Linearisierung ER - TY - JOUR AU - Bigga, Regine ID - 37467 JF - Lehrplanrevision in Schleswig-Holstein TI - Forschungsergebnisse zur Geschlechterfrage - Konsequenzen für die Gestaltung von Unterricht sowie für die Aus- und Weiterbildung von Lehrkräften ER - TY - CONF AU - Müller, Wolfgang AU - Kleinjohann, Bernd ID - 39582 T2 - Proceedings of the 2nd EXPRESS User's Group Conference TI - The EXPRESS Information Modeling Workbench - A New Approach to Graphical Design Environments ER - TY - JOUR AU - MEISSNER, E AU - Noé, Reinhold AU - BORCHERT, B AU - RODLER, H ID - 38499 IS - 25 JF - ELECTRONICS LETTERS SN - 0013-5194 TI - DIRECT MODULATION 565 MBIT/S OPTICAL PSK HETERODYNE SYSTEM WITH SOLITARY SL-QW-DFB LASERS USING NOVEL SUPPRESSION OF PHASE-TRANSITION PERIODS IN CARRIER RECOVERY VL - 28 ER - TY - JOUR AU - Noé, Reinhold AU - RODLER, H AU - EBBERG, A AU - MEISSNER, E AU - BODLAJ, V AU - DROGEMULLER, K AU - WITTMANN, J ID - 38495 IS - 1 JF - ELECTRONICS LETTERS SN - 0013-5194 TI - FULLY ENGINEERED COHERENT MULTICHANNEL TRANSMITTERS AND RECEIVERS WITH LOW-COST POTENTIAL VL - 28 ER - TY - JOUR AU - Noé, Reinhold AU - DROGEMULLER, K ID - 38492 IS - 5 JF - IEEE PHOTONICS TECHNOLOGY LETTERS SN - 1041-1135 TI - ACCURATE AND SIMPLE OPTICAL FREQUENCY STABILIZATION FOR A COHERENT MULTICHANNEL SYSTEM VL - 4 ER - TY - JOUR AU - Kitzerow, Heinz-Siegfried AU - Crooker, P. P. AU - Heppke, G. ID - 40009 IS - 1 JF - Liquid Crystals KW - Condensed Matter Physics KW - General Materials Science KW - General Chemistry SN - 0267-8292 TI - Chromaticity of polymer-dispersed cholesteric liquid crystals VL - 12 ER - TY - JOUR AU - Kitzerow, Heinz-Siegfried AU - Crooker, P. P. ID - 40013 IS - 4 JF - Liquid Crystals KW - Condensed Matter Physics KW - General Materials Science KW - General Chemistry SN - 0267-8292 TI - Behaviour of polymer dispersed cholesteric droplets with negative dielectric anisotropy in electric fields VL - 11 ER - TY - JOUR AU - Kitzerow, Heinz-Siegfried AU - Xu, F. AU - Crooker, P. P. ID - 40008 IS - 6 JF - Liquid Crystals KW - Condensed Matter Physics KW - General Materials Science KW - General Chemistry SN - 0267-8292 TI - Microscopic observations of axial and radial nematic droplets for a dual-frequency addressable liquid crystal VL - 12 ER - TY - JOUR AU - Noé, Reinhold AU - MEISSNER, E AU - BORCHERT, B AU - RODLER, H ID - 38493 IS - 10 JF - IEEE PHOTONICS TECHNOLOGY LETTERS SN - 1041-1135 TI - DIRECT MODULATION 565 MB/S DPSK EXPERIMENT WITH 62.3 DB LOSS SPAN AND ENDLESS POLARIZATION CONTROL VL - 4 ER - TY - JOUR AU - Kitzerow, Heinz-Siegfried AU - Crooker, P. P. AU - Rand, J. AU - Xu, J. AU - Heppke, G. ID - 40075 IS - 3 JF - Journal de Physique II KW - Physics and Astronomy (miscellaneous) KW - General Engineering KW - Atomic and Molecular Physics KW - and Optics SN - 1155-4312 TI - Electrostriction dynamics of blue phase II crystallites VL - 2 ER - TY - JOUR AU - Dolganov, V. K. AU - Heppke, G. AU - Kitzerow, Heinz-Siegfried ID - 40077 IS - 10 JF - Journal de Physique II KW - Physics and Astronomy (miscellaneous) KW - General Engineering KW - Atomic and Molecular Physics KW - and Optics SN - 1155-4312 TI - Dynamic response of a blue phase to an applied field VL - 2 ER - TY - JOUR AU - Kitzerow, Heinz-Siegfried AU - Rand, J. AU - Crooker, P. P. ID - 40078 IS - 2 JF - Journal de Physique II KW - Physics and Astronomy (miscellaneous) KW - General Engineering KW - Atomic and Molecular Physics KW - and Optics SN - 1155-4312 TI - Dynamics of polymer-dispersed cholesteric liquid crystals VL - 2 ER - TY - JOUR AU - Xu, F. AU - Kitzerow, Heinz-Siegfried AU - Crooker, P. P. ID - 40331 IS - 10 JF - Physical Review A KW - Atomic and Molecular Physics KW - and Optics SN - 1050-2947 TI - Electric-field effects on nematic droplets with negative dielectric anisotropy VL - 46 ER - TY - JOUR AU - Kitzerow, Heinz-Siegfried AU - Molsen, Henning AU - Heppke, Gerd ID - 40329 IS - 25 JF - Applied Physics Letters KW - Physics and Astronomy (miscellaneous) SN - 0003-6951 TI - Linear electro‐optic effects in polymer‐dispersed ferroelectric liquid crystals VL - 60 ER - TY - JOUR AU - Kitzerow, Heinz-Siegfried AU - Molsen, Henning AU - Heppke, Gerd ID - 40330 IS - 5 JF - Polymers for Advanced Technologies KW - Polymers and Plastics SN - 1042-7147 TI - Helical unwinding in polymer-dispersed ferroelectric liquid crystals VL - 3 ER - TY - JOUR AB - We investigated the switching behavior of the well-known antiferroelectric liquid crystal (R)-4-(1-methylheptyloxycarbonyl)phenyl-4'-octyloxybiphenyl-4-carboxylate (MHPOBC), embedded in a polymer matrix. The alignment of the liquid crystal in the UV-cured adhesive was controlled by mechanical shear during the polymerization-induced phase separation. Multistable switching with time constants down to 150 µs indicates that antiferroelectric PDLC devices are promissing for electrooptic application as flexible displays. AU - Molsen, Henning AU - Kitzerow, Heinz-Siegfried AU - Heppke, Gerd ID - 40328 IS - 8A JF - Japanese Journal of Applied Physics KW - General Physics and Astronomy KW - General Engineering SN - 0021-4922 TI - Antiferroelectric Switching in Polymer-Dispersed Liquid Crystals VL - 31 ER - TY - JOUR AU - Molsen, H. AU - Kitzerow, Heinz-Siegfried AU - Heppke, G. ID - 40515 JF - SID Digest of Technical Papers TI - Deformed-Helix Ferroelectric Effect in Polymer-Dispersed Ferroelectric Liquid Crystals VL - XXIII ER - TY - JOUR AU - Crooker, P. P. AU - Kitzerow, Heinz-Siegfried ID - 40514 JF - Condensed Matter News TI - Blue Phases VL - 1 ER - TY - JOUR AB - The authors present a detailed study of coherent tunneling oscillations of an optically excited electronic wavepacket in a semiconductor double quantum-well structure. The oscillation of the wavepacket between the two wells is traced by time-resolved pump-probe spectroscopy as well as time-resolved degenerate four-wave mixing. The experimental observations are compared with a simple theoretical model. The motion of the wave packet is studied as a function of both an external electric field and the lattice temperature. While the oscillation frequency shows the expected dependence on electric field, it increases with temperature at fixed electric field when perfectly delocalized electronic states exist at low temperature. AU - Meier, Torsten AU - Leo, K. AU - Shah, J. AU - Damen, T.C. AU - Schulze, A. AU - Schmitt-Rink, S. AU - Thomas, P. AU - Göbel, E.O. AU - Chuang, S.L. AU - Luo, M.S.C. AU - Schäfer, W. AU - Köhler, K. AU - Ganser, P. ID - 43444 IS - 10 JF - IEEE journal of quantum electronics SN - 0018-9197 TI - Dissipative Dynamics of an Electronic Wavepacket in a Semiconductor Double Well Potential VL - 28 ER - TY - JOUR AB - We report the study of optical dephazing of Wannier-Stark ladder excitations in a semiconductor superlattice by means of transient degenerate four-wave mixing. We observe pronounced modulations of the signal with a time period varying linearly with the electric field. The time period is found to equal the temporal periodicity of Bloch oscillations, in agreement with theory. In addition, we find that the dephazing time decreases with increasing localization of the Wannier-Stark states, which is attributed to carrier escape out of the lowest miniband. AU - Meier, Torsten AU - Feldmann, J. AU - Leo, K. AU - Shah, J. AU - Miller, D.A.B. AU - Cunningham, J.E. AU - von Plessen, G. AU - Schulze, A. AU - Thomas, P. AU - Schmitt-Rink, S. ID - 43443 IS - 11 JF - Physical Review B TI - Optical investigation of Bloch oscillations in a semiconductor superlattice VL - 46 ER - TY - JOUR AB - Femtosecond nonlinear laser spectroscopy is applied to study the dynamics of coherent optical excitations in semiconductors. In particular, excitonic excitations in quantum wells and superlattice structures are considered. Two examples demonstrate that four-wave mixing experiments with time-resolved detection of the nonlinear signal are able to distinguish between quantum beats and polarization interference.v AU - Meier, Torsten AU - Göbel, E.O. AU - Koch, M. AU - Feldmann, J. AU - von Plessen, G. AU - Schulze, A. AU - Thomas, P. AU - Schmitt-Rink, S. AU - Köhler, K. AU - Ploog, K. ID - 43445 IS - 1 JF - physica status solidi (b) TI - Time Resolved Four Wave Mixing in GaAs/AlAs Quantum Well Structures VL - 173 ER - TY - CONF AU - Hilleringmann, Ulrich AU - Adams, S AU - Goser, K ID - 39917 T2 - Proceedings ISSSE’92 TI - A Silicon Technology for Monolithic Integration of Optical Waveguides, Photodetectors and VLSI CMOS Circuits ER - TY - CONF AU - Adams, S AU - Hilleringmann, Ulrich AU - Goser, K ID - 39918 T2 - EFOC LAN TI - Electrooptical coupling of waveguides and VLSI circuits integrated on one silicon chip ER - TY - JOUR AU - Schroeter-Wittke, Harald ID - 43483 JF - Der Evangelische Erzieher TI - Michel plays Petrucciani. Oder: "So wenig sind wir auf uns selbst gestellt." Oder: Praktisch-theologische Wahr-Nehmungen in dem "Spielraum von Schnitten" VL - 44 ER - TY - CONF AB - Summary form only given. The numerical investigations are based on a microscopic many-body theory which allows one to compute the linear and nonlinear optical properties of semiconductor superlattices in the presence of homogeneous electric fields applied in the growth direction. The THz-emission due to the field-driven dynamics of photoexcited carriers is investigated for the combined action of static and alternating fields. For a driving field it was shown within a simple model that the equations governing the intraband dynamics in the field-driven superlattice should be analogous to the ones describing the superconducting Josephson junction. The transport properties in this regime can be described by the picture of multi-photon-assisted tunneling between Wannier-Stark states. AU - Meier, Torsten AU - Thomas, P. AU - Koch, S.W. ID - 44291 SN - 1-55752-576-X T2 - Technical Digest. Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference TI - THz-emission from photoexcited semiconductor superlattices with applied ac and dc electric fields ER - TY - CONF AB - Summary form only given. Partly non-degenerate four-wave mixing is able to detect coherent coupling between excitonic resonances like e.g. light-hole and heavy-hole excitons or between an exciton and its continuum states. We apply an extension of this method, which we call selective coherent spectroscopy (SCS), to symmetrically strained (GaIn)As/Ga(PAs) multiple quantum-wells. The samples are excited simultaneously by a picosecond pulse with wavevector k/sub 1/ and a 100 fs pulse with wavevector k/sub 2/. The central wavelength of the picosecond pulse is scanned over the entire spectrum of the 100 fs pulse and the four-wave mixing signal in the direction 2k/sub 2/-k/sub 1/ is detected at a fixed energy. This scan provides an SCS spectrum. AU - Meier, Torsten AU - Euteneuer, A. AU - Finger, E. AU - Hofmann, M. AU - Stolz, W. AU - Thomas, P. AU - Koch, S.W. AU - Ruhle, W.W. ID - 44292 T2 - Technical Digest. Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference TI - Distribution of exciton binding-energies in disordered semiconductor quantum-wells ER - TY - CONF AB - Summary form only given. For a proper understanding of nonlinear optical experiments in semiconductors even the low-density limit Coulomb-induced many body correlations beyond the Hartree-Fock decoupling scheme need to be considered. In the coherent X(3) limit these correlations manifest themselves in the contributions of bound and unbound two-exciton states to the optical response. The understanding of nonlinear excitonic effects in the Stark effect of semiconductors including carrier-correlations is still of fundamental interest. AU - Meier, Torsten AU - Sieh, C. AU - Koch, S.W. AU - Brick, P. AU - Hubner, M. AU - Ell, C. AU - Prineas, J. AU - Khitrova, G. AU - Gibbs, H.M. ID - 44290 SN - 1-55752-576-X T2 - Technical Digest. Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference TI - Influence of carrier-correlations on the optical Stark effect of semiconductors ER - TY - CONF AB - Recent experiments by Roskos et al. in ultrashort optical pulse excitation of biased coupled quantum wells have shown remarkable generation of terahertz electromagnetic radiation. Two different effects were identified: (i) an oscillatory field of frequency corresponding to the separation between the coupled levels in the quantum-well pair (~ 1.5 THz); and (ii) an “instantaneous” electromagnetic field pulse that appears to follow the time evolution of the exciting laser pulse. The oscillatory field is understood to be caused by the coherent oscillation of optically created electrons from one well to the other.[1] The “instantaneous” part we believe is caused by a new mechanism proposed in Ref. 2. The essence of this “instantaneous” mechanism is that electron-hole pairs are created in a biased semiconductor with a net polarization. The density of these pairs follows the light field, as does the induced polarization, hence, generating an electromagnetic source that follows the light pulse. Such mechanisms have been discussed before for photon energies below the optical bandgap energy,[3] although they have so far been difficult to observe. In our work, we have generalized and extended such effects to photon energies above the handgap energy. In this paper we will discuss both of these mechanisms as well as the fourwave-mixing (FWM) signal,[4] and show how they can be understood within one unified formalism. We will also show that the calculations agree well with the experimental results. AU - Meier, Torsten AU - Schulze, A. AU - Scmittrink, S. AU - Thomas, P. AU - Chuang, S.L. ID - 44289 T2 - International Quantum Electronics Conference TI - Terahertz Electromagnetic Pulse Generation and Four-Wave Mixing in Coupled Quantum Wells ER - TY - CONF AB - In the presence of a homogeneous electric field, 𝐹→, each Bloch state in a crystal changes quasimomentum according to the so-called acceleration theorem Thus, in the absence of interband tunneling and scattering processes, each Bloch state moves at a constant velocity in k-space and executes a periodic motion in the reduced zone scheme by undergoing a Bragg reflection between each two traversals of the Brillouin zone. AU - Meier, Torsten AU - von Plessen, G. AU - Schulze, A. AU - Thomas, P. ID - 44288 T2 - International Quantum Electronics Conference TI - On the Observability of Bloch Oscillations in Time-Resolved Four-Wave-Mixing ER - TY - GEN AU - Herzig, Bardo ID - 45259 TI - Entwurf einer Benutzeroberfläche für die Analyse von kontextfreien und DCG - Grammatiken und ihre didaktische Verwendung. Erste Staatsarbeit im Fach Informatik ER - TY - CONF AU - Jonas-Ahrend, Gabriela ID - 47608 TI - Physics Education in East and West Germany ER - TY - CHAP AU - Eke, Norbert Otto ED - Schöwerling, Rainer ED - Steinecke, Hartmut ED - Eke, Norbert Otto ED - Tiggesbäumker, Günter ID - 19432 T2 - Die Fürstliche Bibliothek Corvey. Ihre Bedeutung für eine neue Sicht der Literatur des frühen 19. Jahrhunderts. Beiträge des 1. Internationalen Corvey-Symposions. 25.-27. Oktober 1990 in Paderborn TI - „Wie wird künftig Meusel die hungrige Nachwelt hetzen und peinigen“. Deutsche Romane 1815-1830 in der Fürstlichen Bibliothek Corvey. Vorläufiges zum Forschungsprojekt „Der deutsche Roman 1815-1830" ER - TY - CHAP AB - Angaben zur Herausgeberschaft: Hg. von Rainer Schöwerling und Hartmut Steinecke unter Mitarbeit von Norbert Otto Eke und Günter Tiggesbäumker AU - Eke, Norbert Otto ED - Schöwerling, Rainer ED - Steinecke, Hartmut ED - Eke, Norbert Otto ED - Tiggesbäumker, Günter ID - 19488 T2 - Die Fürstliche Bibliothek Corvey. Ihre Bedeutung für eine neue Sicht der Literatur des frühen 19. Jahrhunderts. Beiträge des 1. Internationalen Corvey-Symposions. 25.-27. Oktober 1990 in Paderborn TI - Diskussionsberichte zu den Sektionen 2 („Roman“) und 3 („Dramen“) sowie der Abschlußdiskussion des 1. Internationalen Corvey-Symposions ER - TY - BOOK AB - Präzisierung der Herausgeberschaft: Hg. von Rainer Schöwerling und Hartmut Steinecke unter Mitarbeit von Norbert Otto Eke und Günter Tiggesbäumker ED - Schöwerling, Rainer ED - Steinecke, Hartmut ED - Eke, Norbert Otto ED - Tiggesbäumker, Günter ID - 19091 TI - Die Fürstliche Bibliothek Corvey. Ihre Bedeutung für eine neue Sicht der Literatur des frühen 19. Jahrhunderts. Beiträge des 1. Internationalen Corvey-Symposions. 25.-27. Oktober 1990 in Paderborn ER - TY - GEN AU - Hilgert, Joachim ID - 51585 T2 - JBer. DMV TI - Fomenko, A.T. Symplectic Geometry (Gordon and Breach, 1988) VL - 94 ER - TY - JOUR AU - Hilgert, Joachim AU - Ólafsson, G. ID - 51442 JF - Japan. J. Math. TI - Analytic Extensions of Representations, the Solvable Case VL - 18 ER - TY - JOUR AU - Hilgert, Joachim ID - 51443 JF - Math. Zeitschrift TI - Controllability on Real Reductive Groups VL - 209 ER - TY - JOUR AU - Flögel, A. AU - Kleine Büning, H. AU - Lettmann, Theodor ID - 19814 JF - RAIRO - Theoretical Informatics and Applications SN - 0988-3754 TI - On the restricted equivalence for subclasses of propositional logic ER - TY - GEN AU - Simon, Jens ID - 2453 TI - Benutzung virtueller Topologien unter PARIX ER - TY - GEN AU - Röttger, Markus AU - Simon, Jens AU - Schroeder, Ulf-Peter ID - 2454 TI - Virtual Topology Library for PARIX ER - TY - GEN AU - Diekmann, Ralf AU - Lüling, Reinhard AU - Simon, Jens ID - 2455 TI - Problem Independent Distributed Simulated Annealing and its Applications ER - TY - CHAP AU - Diekmann, Ralf AU - Simon, Jens ID - 2456 SN - 978-3-642-46787-5 T2 - Applied Simulated Annealing TI - Problem Independent Distributed Simulated Annealing and its Applications VL - 396 ER - TY - GEN AU - Blömer, Johannes ID - 3045 TI - On Kummer theory and the number of roots of unity in radical extensions of Q ER - TY - JOUR AU - Gries, Thomas AU - Wigger, B. ID - 3069 IS - 4 JF - Economia Internationale TI - The Dynamics of Upgrading or how to catch-up VL - 46 ER - TY - BOOK AU - Fuchssteiner, Benno AU - Wiwianka, W. AU - Gottheil, K. AU - Kemper, A. AU - Kluge, O. AU - Morisse, K. AU - Naundorf, H. AU - Oevel, Gudrun AU - Schulze, T. ID - 17302 TI - MuPAD: Multi Processing Algebra Data Tool; Benutzerhandbuch; MuPAD Version 1.1 ER - TY - CONF AU - Peckhaus, Volker ED - Stelzner, Werner ID - 17476 T2 - Philosophie und Logik. Frege-Kolloquien Jena 1989/1991 TI - Ernst Schröder und der Logizismus VL - 3 ER - TY - BOOK ED - Meyer auf der Heide, Friedhelm ED - Monien, B. ED - Rosenberg, A. L. ID - 17477 SN - 0302-9743 TI - Parallel Architectures and Their Efficient Use ER - TY - CHAP AU - Peckhaus, Volker ED - Haller, Rudolf ED - Stadler, Friedrich ID - 17478 T2 - Wien—Berlin—Prag. Der Aufstieg der wissenschaftlichen Philosophie. Zentenarien Rudolf Carnap–Hans Reichenbach–Edgar Zilsel TI - Kurt Grelling und der Logische Empirismus VL - 2 ER - TY - CONF AU - Kastens, Uwe AU - Meyer auf der Heide, Friedhelm AU - Wachsmann, Alf AU - Wichmann, Friedrich ID - 17479 T2 - Proc. 3rd PASA Workshop, PARS Mitteilungen TI - OCCAM-light: A Language Combining Shared Memory and Message Passing (A First Report) ER - TY - JOUR AB - Page 4 AU - Peckhaus, Volker ID - 19046 IS - 4 JF - The Mathematical Intelligencer TI - Fotografie: Ivor Grattan-Guinness (Erlangen, 21.2.1989) VL - 15 ER - TY - BOOK ED - Eke, Norbert Otto ED - Helmes, Günter ID - 19090 TI - Richard Beer-Hofmann (1866-1945). Studien zu seinem Werk ER -