@inproceedings{19967, author = {{Wahby, Mostafa and Divband Soorati, Mohammad and von Mammen, Sebastian and Hamann, Heiko}}, booktitle = {{Proceedings. 25. Computational Intelligence Workshop}}, title = {{{Evolution of Controllers for Robot-Plant Bio-Hybdrids: A Simple Case Study Using a Model of Plant Growth and Motion}}}, year = {{2015}}, } @inproceedings{19980, abstract = {{Fitness function design is known to be a critical feature of the evolutionary-robotics approach. Potentially, the complexity of evolving a successful controller for a given task can be reduced by integrating a priori knowledge into the fitness function which complicates the comparability of studies in evolutionary robotics. Still, there are only few publications that study the actual effects of different fitness functions on the robot's performance. In this paper, we follow the fitness function classification of Nelson et al. (2009) and investigate a selection of four classes of fitness functions that require different degrees of a priori knowledge. The robot controllers are evolved in simulation using NEAT and we investigate different tasks including obstacle avoidance and (periodic) goal homing. The best evolved controllers were then post-evaluated by examining their potential for adaptation, determining their convergence rates, and using cross-comparisons based on the different fitness function classes. The results confirm that the integration of more a priori knowledge can simplify a task and show that more attention should be paid to fitness function classes when comparing different studies.}}, author = {{Hamann, Heiko and Divband Soorati, Mohammad}}, booktitle = {{Proceedings of the Genetic and Evolutionary Computation Conference (GECCO 2015)}}, pages = {{153--160}}, publisher = {{ACM}}, title = {{{The Effect of Fitness Function Design on Performance in Evolutionary Robotics: The Influence of a Priori Knowledge}}}, doi = {{10.1145/2739480.2754676}}, year = {{2015}}, } @inproceedings{19988, author = {{Hamann, Heiko and Schmickl, Thomas and Zahadat, Payam}}, booktitle = {{13th European Conference on Artificial Life (ECAL 2015)}}, pages = {{174}}, publisher = {{MIT Press}}, title = {{{Evolving Collective Behaviors With Diverse But Predictable Sensor States}}}, doi = {{10.7551/978-0-262-33027-5-ch036}}, year = {{2015}}, } @inbook{19989, author = {{Hamann, Heiko and Correll, Nikolaus and Kacprzyk, Janusz and Pedrycz, Witold}}, booktitle = {{Springer Handbook of Computational Intelligence}}, pages = {{1423--1431}}, publisher = {{Springer}}, title = {{{Probabilistic Modeling of Swarming Systems}}}, doi = {{10.1007/978-3-662-43505-2_74}}, year = {{2015}}, } @inproceedings{19990, author = {{Ding, Hongli and Hamann, Heiko}}, booktitle = {{First International Symposium on Swarm Behavior and Bio-Inspired Robotics (SWARM 2015)}}, title = {{{Dependability in Swarm Robotics: Error Detection and Correction}}}, year = {{2015}}, } @inproceedings{19991, author = {{Hamann, Heiko and Schmickl, Thomas and Kengyel, Daniela and Zahadat, Payam and Radspieler, Gerald and Wotawa, Franz}}, booktitle = {{Principles and Practice of Multi-Agent Systems (PRIMA 2015)}}, pages = {{201--217}}, title = {{{Potential of Heterogeneity in Collective Behaviors: A Case Study on Heterogeneous Swarms}}}, year = {{2015}}, } @article{19992, author = {{Valentini, Gabriele and Hamann, Heiko}}, issn = {{1935-3812}}, journal = {{Swarm Intelligence}}, pages = {{153--176}}, title = {{{Time-variant feedback processes in collective decision-making systems: influence and effect of dynamic neighborhood sizes}}}, doi = {{10.1007/s11721-015-0108-8}}, year = {{2015}}, } @inproceedings{20005, author = {{Dorigo, Marco and Hamann, Heiko and Valentini, Gabriele}}, booktitle = {{Proceedings of the 14th Int. Conf. on Autonomous Agents and Multiagent Systems (AAMAS 2015)}}, title = {{{Efficient Decision-Making in a Self-Organizing Robot Swarm: On the Speed Versus Accuracy Trade-Off}}}, year = {{2015}}, } @inproceedings{20006, author = {{Dorigo, Marco and Hamann, Heiko and Valentini, Gabriele}}, booktitle = {{AAAI-15 Video Proceedings}}, title = {{{Self-organized collective decisions in a robot swarm}}}, year = {{2015}}, } @inproceedings{280, abstract = {{The Collaborative Research Centre "On-The-Fly Computing" works on foundations and principles for the vision of the Future Internet. It proposes the paradigm of On-The-Fly Computing, which tackles emerging worldwide service markets. In these markets, service providers trade software, platform, and infrastructure as a service. Service requesters state requirements on services. To satisfy these requirements, the new role of brokers, who are (human) actors building service compositions on the fly, is introduced. Brokers have to specify service compositions formally and comprehensively using a domain-specific language (DSL), and to use service matching for the discovery of the constituent services available in the market. The broker's choice of the DSL and matching approaches influences her success of building compositions as distinctive properties of different service markets play a significant role. In this paper, we propose a new approach of engineering a situation-specific DSL by customizing a comprehensive, modular DSL and its matching for given service market properties. This enables the broker to create market-specific composition specifications and to perform market-specific service matching. As a result, the broker builds service compositions satisfying the requester's requirements more accurately. We evaluated the presented concepts using case studies in service markets for tourism and university management.}}, author = {{Arifulina, Svetlana and Platenius, Marie Christin and Mohr, Felix and Engels, Gregor and Schäfer, Wilhelm}}, booktitle = {{Proceedings of the IEEE 11th World Congress on Services (SERVICES), Visionary Track: Service Composition for the Future Internet}}, pages = {{333----340}}, title = {{{Market-Specific Service Compositions: Specification and Matching}}}, doi = {{10.1109/SERVICES.2015.58}}, year = {{2015}}, } @inproceedings{283, abstract = {{Today, software verification is an established analysis method which can provide high guarantees for software safety. However, the resources (time and/or memory) for an exhaustive verification are not always available, and analysis then has to resort to other techniques, like testing. Most often, the already achieved partial verification results arediscarded in this case, and testing has to start from scratch.In this paper, we propose a method for combining verification and testing in which testing only needs to check the residual fraction of an uncompleted verification. To this end, the partial results of a verification run are used to construct a residual program (and residual assertions to be checked on it). The residual program can afterwards be fed into standardtesting tools. The proposed technique is sound modulo the soundness of the testing procedure. Experimental results show that this combinedusage of verification and testing can significantly reduce the effort for the subsequent testing.}}, author = {{Czech, Mike and Jakobs, Marie-Christine and Wehrheim, Heike}}, booktitle = {{Fundamental Approaches to Software Engineering}}, editor = {{Egyed, Alexander and Schaefer, Ina}}, pages = {{100--114}}, title = {{{Just test what you cannot verify!}}}, doi = {{10.1007/978-3-662-46675-9_7}}, year = {{2015}}, } @article{284, abstract = {{In this work, we present the first scalable distributed information system, that is, a system with low storage overhead, that is provably robust against denial-of-service (DoS) attacks by a current insider. We allow a current insider to have complete knowledge about the information system and to have the power to block any ϵ-fraction of its servers by a DoS attack, where ϵ can be chosen up to a constant. The task of the system is to serve any collection of lookup requests with at most one per nonblocked server in an efficient way despite this attack. Previously, scalable solutions were only known for DoS attacks of past insiders, where a past insider only has complete knowledge about some past time point t0 of the information system. Scheideler et al. [Awerbuch and Scheideler 2007; Baumgart et al. 2009] showed that in this case, it is possible to design an information system so that any information that was inserted or last updated after t0 is safe against a DoS attack. But their constructions would not work at all for a current insider. The key idea behind our IRIS system is to make extensive use of coding. More precisely, we present two alternative distributed coding strategies with an at most logarithmic storage overhead that can handle up to a constant fraction of blocked servers.}}, author = {{Eikel, Martina and Scheideler, Christian}}, journal = {{Transactions on Parallel Computing}}, number = {{3}}, pages = {{18:1----18:33}}, publisher = {{ACM}}, title = {{{IRIS: A Robust Information System Against Insider DoS Attacks}}}, doi = {{10.1145/2809806}}, year = {{2015}}, } @inproceedings{285, abstract = {{We propose an incremental workflow for the verification of parameterized systems modeled as symmetric networks of timed automata. Starting with a small number of timed automata in the network, a safety property is verified using IC3, a state-of-the-art algorithm based on induction.The result of the verification, an inductive strengthening, is reused proposing a candidate inductive strengthening for a larger network.If the candidate is valid, our main theorem states that the safety property holds for all sizes of the network of timed automata. Otherwise the number of automata is increased and the next iteration is started with a new run of IC3.We propose and thoroughly examine optimizations to our workflow, e.g. Feedback mechanisms to speed up the run of IC3.}}, author = {{Isenberg, Tobias}}, booktitle = {{Proceedings of the 15th International Conference on Application of Concurrency to System Design (ACSD)}}, pages = {{1--9 }}, title = {{{Incremental Inductive Verification of Parameterized Timed Systems}}}, doi = {{10.1109/ACSD.2015.13}}, year = {{2015}}, } @misc{286, author = {{Kalde, Benedikt}}, publisher = {{Universität Paderborn}}, title = {{{Implementierung eines hybriden Verschlüsselungsverfahrens nach Cramer und Shoup}}}, year = {{2015}}, } @misc{2865, author = {{Strotmann, Daniela}}, title = {{{Singulärwertzerlegung für μ-ähnliche Bregman-Divergenzen}}}, year = {{2015}}, } @inproceedings{287, abstract = {{The size of modern data centers is constantly increasing. As it is not economic to interconnect all machines in the data center using a full-bisection-bandwidth network, techniques have to be developed to increase the efficiency of data-center networks. The Software-Defined Network paradigm opened the door for centralized traffic engineering (TE) in such environments. Up to now, there were already a number of TE proposals for SDN-controlled data centers that all work very well. However, these techniques either use a high amount of flow table entries or a high flow installation rate that overwhelms available switching hardware, or they require custom or very expensive end-of-line equipment to be usable in practice. We present HybridTE, a TE technique that uses (uncertain) information about large flows. Using this extra information, our technique has very low hardware requirements while maintaining better performance than existing TE techniques. This enables us to build very low-cost, high performance data-center networks.}}, author = {{Wette, Philip and Karl, Holger}}, booktitle = {{Proceedings of the 4th European Workshop on Software Defined Networks (EWSDN 2015)}}, pages = {{1----7}}, title = {{{HybridTE: Traffic Engineering for Very Low-Cost Software-Defined Data-Center Networks}}}, doi = {{10.1109/EWSDN.2015.57}}, year = {{2015}}, } @inproceedings{241, abstract = {{Distributed applications are commonly based on overlay networks interconnecting their sites so that they can exchange information. For these overlay networks to preserve their functionality, they should be able to recover from various problems like membership changes or faults. Various self-stabilizing overlay networks have already been proposed in recent years, which have the advantage of being able to recover from any illegal state, but none of these networks can give any guarantees on its functionality while the recovery process is going on. We initiate research on overlay networks that are not only self-stabilizing but that also ensure that searchability is maintained while the recovery process is going on, as long as there are no corrupted messages in the system. More precisely, once a search message from node u to another node v is successfully delivered, all future search messages from u to v succeed as well. We call this property monotonic searchability. We show that in general it is impossible to provide monotonic searchability if corrupted messages are present in the system, which justifies the restriction to system states without corrupted messages. Furthermore, we provide a self-stabilizing protocol for the line for which we can also show monotonic searchability. It turns out that even for the line it is non-trivial to achieve this property. Additionally, we extend our protocol to deal with node departures in terms of the Finite Departure Problem of Foreback et. al (SSS 2014). This makes our protocol even capable of handling node dynamics.}}, author = {{Scheideler, Christian and Setzer, Alexander and Strothmann, Thim Frederik}}, booktitle = {{Proceedings of the 19th International Conference on Principles of Distributed Systems (OPODIS)}}, title = {{{Towards Establishing Monotonic Searchability in Self-Stabilizing Data Structures}}}, doi = {{10.4230/LIPIcs.OPODIS.2015.24}}, year = {{2015}}, } @inproceedings{242, abstract = {{A fundamental problem for overlay networks is to safely exclude leaving nodes, i.e., the nodes requesting to leave the overlay network are excluded from it without affecting its connectivity. There are a number of studies for safe node exclusion if the overlay is in a well-defined state, but almost no formal results are known for the case in which the overlay network is in an arbitrary initial state, i.e., when looking for a self-stabilizing solution for excluding leaving nodes. We study this problem in two variants: the Finite Departure Problem (FDP) and the Finite Sleep Problem (FSP). In the FDP the leaving nodes have to irrevocably decide when it is safe to leave the network, whereas in the FSP, this leaving decision does not have to be final: the nodes may resume computation when woken up by an incoming message. We are the first to present a self-stabilizing protocol for the FDP and the FSP that can be combined with a large class of overlay maintenance protocols so that these are then guaranteed to safely exclude leaving nodes from the system from any initial state while operating as specified for the staying nodes. In order to formally define the properties these overlay maintenance protocols have to satisfy, we identify four basic primitives for manipulating edges in an overlay network that might be of independent interest.}}, author = {{Koutsopoulos, Andreas and Scheideler, Christian and Strothmann, Thim Frederik}}, booktitle = {{Proceedings of the 17th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS)}}, pages = {{201--216}}, title = {{{Towards a Universal Approach for the Finite Departure Problem in Overlay Networks}}}, doi = {{10.1007/978-3-319-21741-3_14}}, year = {{2015}}, } @inproceedings{243, abstract = {{This paper introduces the problem of communication pattern adaption for a distributed self-adjusting binary search tree. We propose a simple local algorithm, which is closely related to the nearly thirty-year-old idea of splay trees and evaluate its adaption performance in the distributed scenario if different communication patterns are provided.To do so, the process of self-adjustment is modeled similarly to a basic network creation game, in which the nodes want to communicate with only a certain subset of all nodes. We show that, in general, the game (i.e., the process of local adjustments) does not converge, and convergence is related to certain structures of the communication interests, which we call conflicts.We classify conflicts and show that for two communication scenarios in which convergence is guaranteed, the self-adjusting tree performs well.Furthermore, we investigate the different classes of conflicts separately and show that, for a certain class of conflicts, the performance of the tree network is asymptotically as good as the performance for converging instances. However, for the other conflict classes, a distributed self-adjusting binary search tree adapts poorly.}}, author = {{Strothmann, Thim Frederik}}, booktitle = {{Proceedings of the 9th International Workshop on Algorithms and Computation (WALCOM)}}, pages = {{175----186}}, title = {{{The impact of communication patterns on distributed locally self-adjusting binary search trees}}}, doi = {{10.1007/978-3-319-15612-5_16}}, year = {{2015}}, } @phdthesis{246, author = {{Besova, Galina}}, publisher = {{Universität Paderborn}}, title = {{{Systematic Development and Re-Use of Model Tranformations}}}, year = {{2015}}, }