@article{13663, author = {{Wippermann, S. and Schmidt, Wolf Gero}}, issn = {{0039-6028}}, journal = {{Surface Science}}, pages = {{247--250}}, title = {{{Optical anisotropy of the In/Si(111)(4×1)/(8×2) nanowire array}}}, doi = {{10.1016/j.susc.2008.11.013}}, volume = {{603}}, year = {{2008}}, } @inproceedings{63082, author = {{Fechner, Sabine and Sumfleth, Elke}}, booktitle = {{Concept Mapping: Connecting Educators. Proceedings of the Third International Conference on Concept Mapping, Tallinn, Estonia & Helsinki, Finland}}, editor = {{Canas, A. J. and Reiska, P. and Ahlberg, M. and Novak, J.}}, title = {{{Collaborative concept mapping in context-oriented chemistry learning}}}, year = {{2008}}, } @inproceedings{63081, author = {{Fechner, Sabine and Haugwitz, Marion and Sandmann, Angela and Sumfleth, Elke}}, booktitle = {{Proceedings of the NARST 2008 Annual Meeting, Baltimore, MD, USA}}, title = {{{Context-oriented learning and its effects on students' achievement levels in chemistry education}}}, year = {{2008}}, } @article{18564, abstract = {{In the context of photoelectron spectroscopy, the GW approach has developed into the method of choice for computing excitation spectra of weakly correlated bulk systems and their surfaces. To employ the established computational schemes that have been developed for three-dimensional crystals, two-dimensional systems are typically treated in the repeated-slab approach. In this work we critically examine this approach and identify three important aspects for which the treatment of long-range screening in two dimensions differs from the bulk: (1) anisotropy of the macroscopic screening, (2) k-point sampling parallel to the surface, (3) periodic repetition and slab-slab interaction. For prototypical semiconductor (silicon) and ionic (NaCl) thin films we quantify the individual contributions of points (1) to (3) and develop robust and efficient correction schemes derived from the classic theory of dielectric screening.}}, author = {{Freysoldt, Christoph and Eggert, Philipp and Rinke, Patrick and Schindlmayr, Arno and Scheffler, Matthias}}, issn = {{1550-235X}}, journal = {{Physical Review B}}, number = {{23}}, publisher = {{American Physical Society}}, title = {{{Screening in two dimensions: GW calculations for surfaces and thin films using the repeated-slab approach}}}, doi = {{10.1103/PhysRevB.77.235428}}, volume = {{77}}, year = {{2008}}, } @book{17566, author = {{Meyer auf der Heide, Friedhelm}}, isbn = {{ISBN 978-3-939350-41-5}}, publisher = {{Fakultät für Elektrotechnik, Informatik und Mathematik, Universität Paderborn}}, title = {{{The European Integrated Project "Dynamically Evolving, Large Scale Information Systems (DELIS)"}}}, volume = {{222}}, year = {{2008}}, } @book{24366, abstract = {{Dieses Buch beschäftigt sich mit Algorithmen und Methoden der Peer-to-Peer-Netzwerke und gibt einen Einblick in die aktuelle Forschung. Ursprünglich waren Peer-to-Peer-Netzwerke nur für File-Sharing konzipiert. Mittlerweile hat sich Peer-to-Peer zum Paradigma für Rechnernetzwerke entwickelt. Ziel dieses Buches ist es, dem Leser ein grundlegendes Verständnis der Techniken hinter den aktuellen Peer-to-Peer-Netzwerken aufzuzeigen und im nächsten Schritt Algorithmen vorzustellen, die vielleicht erst in einigen Jahren umgesetzt werden. Das Buch richtet sich in erster Linie an Informatiker (Studenten ab dem 5. Semester). Aber auch interessierte Nichtinformatiker können von diesem Buch profitieren, wobei grundlegende Kenntnisse aus den Bereichen der Mathematik und Informatik vorausgesetzt werden. Die Ziele, Kernaussagen und Ergebnisse sollten jedoch auch ohne akademischen Hintergrund klar werden.}}, author = {{Mahlmann, Peter and Schindelhauer, Christian}}, isbn = {{9783540339915}}, publisher = {{Springer}}, title = {{{Peer-to-Peer-Netzwerke}}}, doi = {{10.1007/978-3-540-33992-2}}, year = {{2007}}, } @inproceedings{3222, author = {{Derrick, John and Schellhorn, Gerhard and Wehrheim, Heike}}, booktitle = {{Integrated Formal Methods, 6th International Conference, {IFM} 2007, Oxford, UK, July 2-5, 2007, Proceedings}}, editor = {{Davies, Jim and Gibbons, Jeremy}}, pages = {{195----214}}, title = {{{Proving Linearizability Via Non-atomic Refinement}}}, doi = {{10.1007/978-3-540-73210-5_11}}, year = {{2007}}, } @article{27789, author = {{Buyken, Anette and von Eckardstein, Arnold and Schulte, Helmut and Cullen, Paul and Assmann, Gerd}}, issn = {{1741-8267}}, journal = {{European Journal of Cardiovascular Prevention & Rehabilitation}}, pages = {{230--236}}, title = {{{Type 2 diabetes mellitus and risk of coronary heart disease: results of the 10-year follow-up of the PROCAM study}}}, doi = {{10.1097/hjr.0b013e3280142037}}, year = {{2007}}, } @inproceedings{20434, abstract = {{Current research in Micro, Nano and Swarm Robots as results of the European projects Miniman, MiCRoN and I-SWARM will be presented. First, the design and the control of 5 to 10cm3 sized mobile micro robots with five degrees of freedom will be shown. They can handle miniaturized parts as for example an optical component or a biological cell with a size in the micrometre-area with an accuracy of 100nm under a microscope or a raster-electron microscope. Second, the design and the control of a 1cm3-sized mobile untethered micro robot will be demonstrated. Here, the robot consists of five parts: the Piezzo locomotion module, the micro control unit, the communication unit, the navigation system and the micro gripper. The mobile robot can be guided and positioned in an arena with an accuracy of 5 micrometre and can be programmed and controlled over the wireless communication unit. Third, the design and the control of 3 × 3 × 3 mm3 sized micro-/nanorobots with 2 degrees of freedom will be presented. The transmission of energy and the communication between the robots is realized via infrared. The robot controller is fully integrated and has limited functionalities. Via basic sensors communication functions and elementary rules and behaviours the micro robot can act in a swarm consisting of hundreds and thousands of robots. Future applications could be monitoring-, inspection-, exploring-tasks etc. of big areas or objects.}}, author = {{Hamann, Heiko and Szymanski, Marc and Wörn, Heinz and Estana, Ramon and Xie, Ming and Dubowsky, Steven}}, booktitle = {{Advances in Climbing and walking robots. Proceedings of 10th International Conference (CLAWAR'07), Singapore, July 16-18}}, pages = {{15----24}}, title = {{{From Micro to Nano and Swarm Robotics}}}, doi = {{10.1142/9789812770189_0003}}, year = {{2007}}, } @article{17980, author = {{Ziegler, Martin}}, issn = {{1571-0661}}, journal = {{Electronic Notes in Theoretical Computer Science}}, pages = {{255--274}}, title = {{{Revising Type-2 Computation and Degrees of Discontinuity}}}, doi = {{10.1016/j.entcs.2006.08.015}}, year = {{2007}}, } @inbook{18593, abstract = {{We present a quantitative parameter-free method for calculating defect states and charge-transition levels of point defects in semiconductors. It combines the strength of density-functional theory for ground-state total energies with quasiparticle corrections to the excitation spectrum obtained from many-body perturbation theory. The latter is implemented within the G0W0 approximation, in which the electronic self-energy is constructed non-self-consistently from the Green’s function of the underlying Kohn–Sham system. The method is general and applicable to arbitrary bulk or surface defects. As an example we consider anion vacancies at the (110) surfaces of III–V semiconductors. Relative to the Kohn–Sham eigenvalues in the local-density approximation, the quasiparticle corrections open the fundamental band gap and raise the position of defect states inside the gap. As a consequence, the charge-transition levels are also pushed to higher energies, leading to close agreement with the available experimental data.}}, author = {{Schindlmayr, Arno and Scheffler, Matthias}}, booktitle = {{Theory of Defects in Semiconductors}}, editor = {{Drabold, David A. and Estreicher, Stefan K.}}, isbn = {{978-3-540-33400-2}}, issn = {{1437-0859}}, pages = {{165--192}}, publisher = {{Springer}}, title = {{{Quasiparticle calculations for point defects at semiconductor surfaces}}}, doi = {{10.1007/11690320_8}}, volume = {{104}}, year = {{2007}}, } @inproceedings{18656, abstract = {{In the StrSort model [2], the input is given as a stream, e.g. a sequence of points, and an algorithm can perform (a) streaming and (b) sorting passes to process the stream. A streaming pass reads the input stream from left to right and writes an output stream, which is the input of the next pass. A sorting pass is a black box operation that sorts a stream according to some partial order. In this paper, we develop algorithms for two basic geometric problems in the StrSort model. At first, we propose a divide-and-conquer algorithm that computes the convex hull of a point set in 2D in O(log2 n) passes using O(1) memory. Then we give a StrSort algorithm to compute a (1+ε)-spanner for a point set in Rd for constant d and constant epsilon that uses O(logd-1 n) passes and O(log n) space. This result implies a (1+ε)-approximation of the Euclidean minimum spanning tree in Rd, for constant d and ε.}}, author = {{Sohler, Christian and Lammersen, Christiane}}, booktitle = {{Proceedings of the 23rd European Workshop on Computational Geometry (EWCG)}}, pages = {{69--72}}, title = {{{StrSort Algorithms for Geometric Problems}}}, year = {{2007}}, } @inproceedings{22330, author = {{Frank, Ursula and Gausemeier, Jürgen and Schmidt, Alexander and Zimmer, Detmar}}, booktitle = {{Internationales Forum Mechatronik. Intelligente Systeme und Module}}, isbn = {{978-3-033-01192-2}}, publisher = {{Züricher Hochschule für Angewandte Wissenschaften Institut für Mechatronische Systeme}}, title = {{{Von der Mechatronik zur Selbstoptimierung}}}, year = {{2007}}, } @inproceedings{9562, abstract = {{Penetration tests (Magness-Taylor, force/deformation, Kramer multiblade shear) applied directly over the peel of the fruit are the most acceptable methods for measuring firmness and turgidity of fruits and vegetables [1, 2]. To replace these destructive and mechanical penetration methods by non-destructive ultrasonic measurements implies a great advance in order to obtain fast studies about the state of the fruit at the time of harvest, during storage, and in the distribution points. Moreover, there are other advantages since this technique can be fast, non-destructive, fully automated, and performed on-line [1]. Within this context, the objective of this study was to examine the relationship between physico-mechanical characteristics (oil-gland break stress, thickness and dehydration) and ultrasonic characteristics in the ``Salustiana'' orange peel during the complete dehydration process of the orange at ambient conditions. After a description of the measurement system [3], the fruit selection procedure and the measurement protocol, we analyze the results of the change of physico-mechanical and ultrasonic properties in the orange peel and their change with storage time.}}, author = {{Camarena Gandia, Francisco and Hemsel, Tobias and Espinosa, Victor and Twiefel, Jens and Ardid, Miquel and Martinez-Mora, Joan and Gandia, Joan Babtiste}}, booktitle = {{Proceedings of 19th international congress on Acoustics, Madrid}}, title = {{{Non-destructive ultrasonic test of orange dehydration}}}, year = {{2007}}, } @inproceedings{4495, author = {{Sporer, Thomas and Jenert, Tobias and Reinmann, Gabi}}, booktitle = {{4. Konferenz Professionelles Wissensmanagement - Erfahrungen und Visionen}}, location = {{Potsdam}}, pages = {{269--276}}, title = {{{Learning about innovation and knowledge creation in higher education.}}}, volume = {{2}}, year = {{2007}}, } @article{7597, author = {{Tönnies, Merle}}, journal = {{Spatial Practices 2}}, pages = {{305--324}}, publisher = {{Rodopi}}, title = {{{Constructing an Emblematic Northern Space. The New Brighton Photographs of Martin Parr and Tom Wood}}}, year = {{2007}}, } @inproceedings{8416, author = {{Ryndina, Ksenia and Küster, Jochen and Gall, Harald}}, booktitle = {{Models in Software Engineering (1st Workshop on Quality in Modeling at MoDELS 2006, Genoa (Italy))}}, pages = {{80--90}}, publisher = {{Springer}}, title = {{{Consistency of Business Process Models and Object Life Cycles}}}, doi = {{http://dx.doi.org/10.1007/978-3-540-69489-2}}, volume = {{4364/2007}}, year = {{2007}}, } @article{5658, abstract = {{Email communication is encumbered with a mass of email messages which their recipients have neither requested nor require. Even worse, the impacts of these messages are far from being simply an annoyance, as they also involve economic damage. This manuscript examines the resource ?email addresses?, which is vital for any potential bulk mailer and spammer. Both a methodology and a honeypot conceptualization for implementing an empirical analysis of the usage of email addresses placed on the Internet are proposed here. Their objective is to assess, on a quantitative basis, the extent of the current harassment and its development over time. This ?framework? is intended to be extensible to measuring the effectiveness of address-obscuring techniques. The implementation of a pilot honeypot is described, which led to key findings, some of them being: (1) Web placements attract more than two-thirds (70\%) of all honeypot spam emails, followed by newsgroup placements (28.6\%) and newsletter subscriptions (1.4\%), (2) the proportions of spam relating to the email addresses? top-level domain can be statistically assumed to be uniformly distributed, (3) More than 43\% of addresses on the web have been abused, whereas about 27\% was the case for addresses on newsgroups and only about 4\% was the case for addresses used for a newsletter subscription, (4) Regarding the development of email addresses? attractiveness for spammers over time, the service ?web sites? features a negative linear relationship, whereas the service ?Usenet? hows a negative exponential relationship. (5) Only 1.54\% of the spam emails showed an interrelation between the topic of the spam email and that of the location where the recipient?s address was placed, so that spammers are assumed to send their emails in a ?context insensitive? manner. The results of the empirical analysis motivate the need for the protection of email addresses through obscuration. We analyze this need by formulating requirements for address obscuring techniques and we reveal to which extent today?s most relevant approaches fulfill these requirements.}}, author = {{Schryen, Guido}}, journal = {{Computers & Security}}, keywords = {{Address-obfuscating techniques, email, empirical analysis, honeypot, security by design, security by obscurity, spam}}, number = {{5}}, pages = {{361--372}}, publisher = {{Elsevier}}, title = {{{The Impact that Placing Email Addresses on the Internet has on the Receipt of Spam ? An Empirical Analysis}}}, volume = {{2}}, year = {{2007}}, } @inproceedings{15339, abstract = {{Continuous and reliable concentration measurement of liquids still is a great challenge as the sensor systems have to meet high industrial requirements. Apart from chemical sensors there are a couple of acoustic systems [1] that are well suited for a lot of industrial applications. Most of them determine the amplitude ratio of deflected ultrasound bursts at different boundaries as well as the sound velocity of the liquid in order to calculate its acoustic impedance and therewith its density. The advantages of acoustic sensors are their robustness and their fast response. Their disadvantages are sensitivity against variations of the reference material properties as well as abrasion or soiling of the boundaries. This contribution is about a new model-based method that uses the whole surface of an acoustic waveguide as reference boundary: It has turned out that the principal components of a signal at the end of the waveguide can be assigned to the different propagative acoustic modes (Fig. 1). Therefore it is necessary to use different simulation tools, e.g. FEM and modal analysis (Fig. 2). With this it is possible to determine the amplitudes of each mode by means of one measured signal at the end of the waveguide and Gauss Algorithm even if the transducer is of very simple kind [2]. Therewith it is possible to get redundant information -- one amplitude for each mode -- for the liquid impedance. In addition to that it is possible to generate an acoustic reference signal without information about the liquid impedance but dissipation if we use the fundamental mode. The different signal amplitudes and a model of acoustic wave propagation [2, 3] offer the possibility to distinguish between dissipation in the liquid and attenuation due to the impedance relations. Moreover, if there are enough analysable amplitudes available, variations of the reference material properties can be determined.}}, author = {{Rautenberg, Jens and Henning, Bernd}}, isbn = {{978-3-9810993-2-4}}, location = {{Nürnberg}}, pages = {{87--92}}, title = {{{New approach for the reliable measurement of acoustic impedance of liquids in an acoustic waveguide}}}, volume = {{II}}, year = {{2007}}, } @inproceedings{15344, abstract = {{In many applications ultrasonic transducers are used for transmitting and receiving ultrasonic waves. Ultrasonic sensor systems meet the practical requirements of industrial applications quite well. Typical sensor applications are for example the measurement of distance and thickness. Especially if only one ultrasonic transceiver and the well-known pulse-echo-method are used, the sensor electronics has to switch from transmitting to receiving mode. This is one of the most limiting properties because the probe can not receive echoes from nearby obstacles or thin material layers. This contribution deals with the development of an electronic interface circuit for ultrasonic sensors allowing transmitting and receiving of acoustic signals simultaneously. There are already several methods to separate the transmitted from the received signal for instance the well-known circulator in the telephone, the differential transformer mentioned by Bradfield [1] or a directional coupler [2]. The directional coupler consists of two broadband transformers linked with each other in such a way that it equally distributes the input power at port one to the third and fourth port, while port two is isolated. This circuit is also known as 3 dB directional coupler and makes it possible to get reference echoes directly from the interface between the sensor and the medium of interest. Several reflectors or multiple sound paths such as used in ultrasonic density measurement systems are unnecessary [3].}}, author = {{Vössing, Torsten and Rautenberg, Jens and Kehl, Romina and Henning, Bernd}}, isbn = {{978-3-9810993-2-4}}, location = {{Nuremberg}}, title = {{{Simultaneous transmitting and receiving with ultrasonic sensors}}}, year = {{2007}}, }