@inproceedings{18279,
  abstract     = {{For $c in REAL$, a $c$-spanner is a subgraph of a complete Euclidean graph satisfying that between any two vertices there exists a path of weighted length at most $c$ times their geometric distance. Based on this property to approximate a complete weighted graph, sparse spanners have found many applications, e.g., in FPTAS, geometric searching, and radio networks. For geometric searching, it turned out to suffice whether the radius rather than the length of some path between any two vertices is bounded relatively to their geometric distance; this is the defining property of weak spanners. Finally regarding radio network applications, a power spanner accounts for the total energy afforded for a wireless transmission with the requirement that the sum of the squares of the lengths of some path between any two planar vertices must be bounded relatively to the square of their geometric distance (or higher powers up to 6 or even 8).<br><br>While it is known that any $c$-spanner is also both a weak $C_1$-spanner and a $C_2$-power spanner (for appropriate $C_1,C_2$ depending only on $c$ but not on the graph under consideration), we show that the converse fails: There exists a family of $c_1$-power spanners that are no weak $C$-spanners and also a family of weak $c_2$-spanners that are no $C$-spanners for any fixed $C$ (and thus no uniform spanners, either). However the deepest result of the present work reveals that, surprisingly, any weak spanner is also a uniform power spanner. We further generalize the latter notion by considering $(c,delta)$-power spanners where the sum of the $delta$-th powers of the lengths has to be bounded; so $(cdot,2)$-power spanners coincide with the usual power spanners and $(cdot,1)$-power spanners are classical spanners. Interestingly, these $(cdot,delta)$-power spanners form a strict hierarchy where the above results still hold for any $deltageq2$; some even hold for $delta>1$ while counterexamples reveal others to fail for $delta<2$. In fact we show that in general every self-similar curve of fractal dimension $d>delta$ is no $(C,delta)$-power spanner for any fixed $C$. }},
  author       = {{Schindelhauer, Christian and Volbert, Klaus and Ziegler, Martin}},
  booktitle    = {{Proc. of 15th Annual International Symposium on Algorithms and Computation (ISAAC'04)}},
  isbn         = {{9783540241317}},
  issn         = {{0302-9743}},
  pages        = {{805--821}},
  publisher    = {{Springer }},
  title        = {{{Spanners, Weak Spanners, and Power Spanners for Wireless Networks}}},
  doi          = {{10.1007/978-3-540-30551-4_69}},
  volume       = {{3341}},
  year         = {{2004}},
}

@inproceedings{18364,
  abstract     = {{The visualisation of manufacturing-processes assists the user in understanding and analysis.
Typically he can move free and unguided in a virtual environment which visualizes the entire
process. Thus knowledge and conclusions are to some extend acquired on a random base.
This article describes the development of a tool, which enables the user to interactively improve
significant production processes in the simulation. He moves in a virtual 3D-environment
(walkthrough system) and is able to acquire automatically calculated indications for significant
processes. At the same time the simulation considers significant objects in a more detailed way. If
the viewer is interested in a significant process, he is automatically guided to the relevant location
where he can examine the critical situation by modification of the simulation model.}},
  author       = {{Mueck, Bengt and Dangelmaier, Wilhelm and Laroque, Christoph  and Fischer, Matthias and Kortenjan, Michael}},
  booktitle    = {{Simulation and Visualisation 2004}},
  pages        = {{73--83}},
  publisher    = {{SCS European Publishing House}},
  title        = {{{Guidance of Users in Interactive 3D-Visualisations of Material Flow Simulations}}},
  year         = {{2004}},
}

@article{18447,
  author       = {{Oesterdiekhoff, Brigitte}},
  journal      = {{Informatik Spektrum}},
  number       = {{5}},
  pages        = {{448--452}},
  title        = {{{Transcoding von Webinhalten}}},
  volume       = {{27}},
  year         = {{2004}},
}

@inproceedings{18448,
  author       = {{Oesterdiekhoff, Brigitte}},
  booktitle    = {{Proceedings of IFIP Working Conference on Distributed and Parallel Embedded Systems (DIPES'04)}},
  title        = {{{Internet Premium Services for Flexible Format Distributed Devices}}},
  year         = {{2004}},
}

@inproceedings{16474,
  abstract     = {{Given n distinct points p1, p2, ... , pn in the plane, the map labeling
problem with four squares is to place n axis-parallel equi-sized squares Q1, ... ,Qn
of maximum possible size such that pi is a corner of Qi and no two squares overlap.
This problem is NP-hard and no algorithm with approximation ratio better
than 1/2 exists unless P = NP [10].
In this paper, we consider a scenario where we want to visualize the information
gathered by smart dust, i.e. by a large set of simple devices, each consisting of
a sensor and a sender that can gather sensor data and send it to a central station.
Our task is to label (the positions of) these sensors in a way described by the
labeling problem above. Since these devices are not positioned accurately (for
example, they might be dropped from an airplane), this gives rise to consider the
map labeling problem under the assumption, that the positions of the points are
not fixed precisely, but perturbed by random noise. In other words, we consider
the smoothed complexity of the map labeling problem. We present an algorithm
that, under such an assumption and Gaussian random noise with sufficiently large
variance, has linear smoothed complexity.}},
  author       = {{Bansal, Vikas and Meyer auf der Heide, Friedhelm and Sohler, Christian}},
  booktitle    = {{12th Annual European Symposium on Algorithms (ESA 2004)}},
  isbn         = {{9783540230250}},
  issn         = {{0302-9743}},
  title        = {{{Labeling Smart Dust}}},
  doi          = {{10.1007/978-3-540-30140-0_9}},
  volume       = {{3221}},
  year         = {{2004}},
}

@inproceedings{16475,
  author       = {{Bienkowski, Marcin and Korzeniowski, Miroslaw and Meyer auf der Heide, Friedhelm}},
  booktitle    = {{Proceedings of the sixteenth annual ACM symposium on Parallelism in algorithms and architectures  - SPAA '04}},
  isbn         = {{1581138407}},
  title        = {{{Fighting against two adversaries}}},
  doi          = {{10.1145/1007912.1007923}},
  year         = {{2004}},
}

@article{16477,
  author       = {{Meyer auf der Heide, Friedhelm and Schindelhauer, Christian and Volbert, Klaus and Grünewald, Matthias}},
  issn         = {{1432-4350}},
  journal      = {{Theory of Computing Systems}},
  pages        = {{343--370}},
  title        = {{{Congestion, Dilation, and Energy in Radio Networks}}},
  doi          = {{10.1007/s00224-004-1124-z}},
  year         = {{2004}},
}

@inproceedings{16480,
  author       = {{Leonardi, S. and Marchetti-Spaccamela, A. and Meyer auf der Heide, Friedhelm}},
  booktitle    = {{SPAA '04: Proceedings of the sixteenth annual ACM symposium on Parallelism in algorithms and architectures}},
  isbn         = {{1581138407}},
  title        = {{{Scheduling against an adversarial network}}},
  doi          = {{10.1145/1007912.1007936}},
  year         = {{2004}},
}

@article{16399,
  abstract     = {{We present a new data structure for rendering highly complex virtual environments of arbitrary topology. The special feature of our approach is that it allows an interactive navigation in very large scenes (30 GB/400 million polygons in our benchmark scenes) that cannot be stored in main memory, but only on a local or remote hard disk. Furthermore, it allows interactive rendering of substantially more complex scenes by instantiating objects.

The sampling process is done in the preprocessing. There, the polygons are randomly distributed in our hierarchical data structure, the randomized sample tree. This tree only uses space that is linear in the number of polygons. In order to produce an approximate image of the scene, the tree is traversed and polygons stored in the visited nodes are rendered. During the interactive walkthrough, parts of the sample tree are loaded from local or remote hard disk.

We implemented our algorithm in a prototypical walkthrough system. Analysis and experiments show that the quality of our images is comparable to images computed by the conventional z-buffer algorithm regardless of the scene topology.}},
  author       = {{Klein, Jan and Krokowski, Jens and Fischer, Matthias and Wand, Michael and Wanka, Rolf and Meyer auf der Heide, Friedhelm}},
  issn         = {{1054-7460}},
  journal      = {{Presence: Teleoperators and Virtual Environments}},
  pages        = {{617--637}},
  title        = {{{The Randomized Sample Tree: A Data Structure for Interactive Walk-Throughs in Externally Stored Virtual Environments}}},
  doi          = {{10.1162/1054746043280619}},
  year         = {{2004}},
}

@inproceedings{13071,
  author       = {{Liu Jing, Michelle and Ruehrup, Stefan and Schindelhauer, Christian and Volbert, Klaus and Dierkes, Martin and Bellgardt, Andreas and Ibers, Rüdiger and Hilleringmann, Ulrich}},
  booktitle    = {{{GOR/NGB Conference Tilburg 2004}}},
  title        = {{{Sensor Networks with More Features Using Less Hardware}}},
  year         = {{2004}},
}

@article{19726,
  abstract     = {{The Paderborn University BSP (PUB) library is a C communication library based on the BSP model. The basic library supports buffered as well as unbuffered non-blocking communication between any pair of processors and a mechanism for synchronizing the processors in a barrier style. In addition, PUB provides non-blocking collective communication operations on arbitrary subsets of processors, the ability to partition the processors into independent groups that execute asynchronously from each other, and a zero-cost synchronization mechanism. Furthermore, some techniques used in the implementation of the PUB library deviate significantly from the techniques used in other BSP libraries.}},
  author       = {{Bonorden, Olaf and Juurlink, Bernhardus and von Otte, Ingo and Rieping, Ingo}},
  issn         = {{0167-8191}},
  journal      = {{Parallel Computing}},
  pages        = {{187--207}},
  title        = {{{The Paderborn University BSP (PUB) library}}},
  doi          = {{10.1016/s0167-8191(02)00218-1}},
  year         = {{2003}},
}

@article{19785,
  author       = {{Salzwedel, Kay A.}},
  isbn         = {{9783540008835}},
  issn         = {{0302-9743}},
  journal      = {{Algorithms for Memory Hierarchies}},
  title        = {{{Algorithmic Approaches for Storage Networks}}},
  doi          = {{10.1007/3-540-36574-5_12}},
  volume       = {{2625}},
  year         = {{2003}},
}

@inproceedings{19790,
  abstract     = {{The advances in Internet technology have led to tremendous improvements in business, education, and science and have changed the way we think, live, and communicate. Information exchange has become ubiquitous by the possibilities offered through modern technologies. We are able to offer information 24 hours a day through our web sites and can leave messages every time and from anywhere in the world. This change in communication has led to new challenges. Enterprises have to deal with an information amount that doubles every year. The technological foundation to cope with this information explosion is given by Storage Area Networks (SANs), which are able to connect a great number of storage systems over a fast interconnection network. However, to be able to use the benefits of a SAN, an easy-to-use and efficient management support has to be given to the storage administrator. In this paper, we will suggest new storage management concepts and we will introduce a new management environment that is able to significantly reduce management costs and increases the performance and resource utilization of the given SAN infrastructure.}},
  author       = {{Scheideler, Christian and Salzwedel, Kay and Meyer auf der Heide, Friedhelm and Brinkmann, André and Vodisek, Mario and Rückert, Ulrich}},
  booktitle    = {{Proceedings of SSGRR 2003}},
  title        = {{{Storage Management as Means to cope with Exponential Information Growth}}},
  year         = {{2003}},
}

@inproceedings{19806,
  abstract     = {{We try to close the gap between theoretical investigations of wireless network topologies and realistic wireless environments. For point-to-point communication, we examine theoretically well-analyzed sparse graphs, i.e. the Yao-graph, the SparsY-graph, and the SymmY-graph.  We present distributed algorithms that can be used to build up these graphs in time $O(log n)$ per node without the use of any geo-graphical positioning system. Our algorithms are based only on local knowledge and local decisions and make use of power control to establish communication links with low energy-cost.  We compare these algorithms with respect to congestion, dilation, and energy. For congestion we introduce different measures that allow us to investigate the difference between real-world wireless networks and models for wireless communication at a high level of abstraction. For more realistic simulations we extend our simulation  environment SAHNE. We use a realistic transmission model for directed communication that uses sector subdivision.  Finally, our experimental results show that our topologies and algorithms work well in a distributed environment and we give some recommendations for the topology control based on our simulations.}},
  author       = {{Rührup, Stefan and Schindelhauer, Christian  and Volbert, Klaus and Grünewald, M.}},
  booktitle    = {{Proceedings of the International Parallel and Distributed Processing Symposium (IPDPS)}},
  isbn         = {{0769519261}},
  title        = {{{Performance of distributed algorithms for topology control in wireless networks}}},
  doi          = {{10.1109/ipdps.2003.1213107}},
  year         = {{2003}},
}

@misc{19828,
  author       = {{Mahlmann, Peter}},
  title        = {{{Implementierung und Vergleich von Verfahren zum Information Retrieval im World Wide Web}}},
  year         = {{2003}},
}

@inproceedings{19833,
  abstract     = {{Communication facilities are important in Robotics if several robots have to work together. In this paper, we describe problems and solutions encountered while designing an infrared-based communication device for the mini robot Khepera. In contrast to traditional omnidirectional systems, it features directed, power-variable transmission in eight directions at unit[23.4]kbps up to a range of unit[1m]. It can differentiate incoming data signals from interference from adjacent sectors and can estimate their direction-of-arrival. We model the transmission over the infrared channel and show how interference influences the reception of the data signals. We also describe methods how to reduce these effects. We have tested the performance of the resulted signal processing in a worst case scenario by simulations and in experiments with a prototype implementation. The resulted module is  especially suited for experimental evaluation of ad hoc network protocols and for position estimation.}},
  author       = {{Volbert, Klaus and Grünewald, Matthias and Schindelhauer, Christian and Rückert, Ulrich}},
  booktitle    = {{Proceedings of the 2nd International Conference on Autonomous Minirobots for Research and Edutainment}},
  pages        = {{113--122}},
  title        = {{{Directed power-variable infrared communication for the mini robot Khepera}}},
  year         = {{2003}},
}

@inproceedings{19874,
  abstract     = {{We present a novel framework for hierarchical collision detection that can be applied to virtually all bounding volume (BV) hierarchies. It allows an application to trade quality for speed. Our algorithm yields an estimation of the quality, so that applications can specify the desired quality. In a timecritical system, applications can specify the maximum time budget instead, and quantitatively assess the quality of the results returned by the collision detection afterwards.}},
  author       = {{Klein, Jan and Zachmann, Gabriel}},
  booktitle    = {{Proc. 8th International Fall Workshop Vision, Modeling, and Visualization (VMV 2003)}},
  pages        = {{37--45}},
  title        = {{{ADB-Trees: Controlling the Error of Time-Critical Collision Detection}}},
  year         = {{2003}},
}

@inproceedings{19900,
  author       = {{Klein, Jan and  Zachmann, Gabriel}},
  booktitle    = {{ Proc. ACM Symposium on Virtual Reality Software and Technology (VRST 2003)}},
  pages        = {{22--31}},
  title        = {{{Time-Critical Collision Detection Using an Average-Case Approach}}},
  doi          = {{10.1145/1008653.1008660}},
  year         = {{2003}},
}

@inproceedings{19952,
  abstract     = {{Graph minors theory, developed by Robertson & Seymour, provides a list of powerful theoretical results and tools. However, the wide spread opinion in Graph Algorithms community about this theory is that it is mainly of theoretical importance. The main purpose of this paper is to show how very deep min-max and duality theorems from Graph Minors can be used to obtain essential speed-up to many known algorithms on different domination problems.}},
  author       = {{Fomin, Fedor V. and Thilikos, Dimitrios M.}},
  booktitle    = {{Proceedings of the 14th ACM-SIAM Symposium on Discrete Algorithms (SODA 2003)}},
  issn         = {{0097-5397}},
  title        = {{{Dominating Sets in Planar Graphs: Branch-Width and Exponential Speed-Up}}},
  doi          = {{10.1137/s0097539702419649}},
  year         = {{2003}},
}

@inproceedings{24273,
  author       = {{Terbahl, Martina and Krokowski, Jens}},
  booktitle    = {{Proceedings of 5. GI-Informatiktage 2003}},
  title        = {{{Verteiltes Rendern durch dynamische Bildaufteilung}}},
  year         = {{2003}},
}