System monitors need oracles to determine whether observed traces are acceptable. One method is to compare the observed traces to a formal model of the system. Unfortunately, such models are not always available - sof...
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ISBN:
(纸本)9781612081687
System monitors need oracles to determine whether observed traces are acceptable. One method is to compare the observed traces to a formal model of the system. Unfortunately, such models are not always available - software may be developed without generating a formal model, or the implementation deviates from the original specification. In previous work, we have proposed a learning algorithm to construct a formal model of the software from its test cases, thereby providing a means to transform test cases for offline testing into an oracle for monitoring. In this paper, we refine our learning algorithm with a set of state-merging rules that help to exploit the test cases for additional information. Using the additional information mined from the test cases, models can be learned from smaller test suites.
The gUSE (Grid User Support Environment) framework allows to create, store and distribute application workflows. This workflow architecture includes a wide variety of payload execution operations, such as loops, condi...
The gUSE (Grid User Support Environment) framework allows to create, store and distribute application workflows. This workflow architecture includes a wide variety of payload execution operations, such as loops, conditional execution of jobs and combination of output. These complex multi-job workflows can easily be created and modified by application developers through the WS-PGRADE portal. The portal also allows end users to download and use existing workflows, as well as executing them. The DIRAC framework for distributed computing, a complete Grid solution for a community of users needing access to distributed computing resources, has been integrated into the gUSE/WS-PGRADE system. This integration allows the execution of gUSE workflows in a distributed computing environment, thus greatly expanding the capability of the portal to several Grids and Cloud Computing facilities. The main features and possibilities of the gUSE/WS-PGRADE-DIRAC system, as well as the benefits for users, will be outlined and discussed.
In this paper, we present an approach for identity and access management (IAM) in the context of (cross-organizational) serviceoriented architectures (SOA). In particular, we defined a domainspecific language (DSL) fo...
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The project MoSGrid (Molecular Simulation Grid) has been developing a web-based science gateway supporting the community with various services for quantum chemistry, molecular modeling, and docking. Users gain access ...
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Next to traditional communication systems like servers or routers at the backbone and personal computers or laptops acting as clients, the Future Internet will additionally comprise many so-called smart objects. Most ...
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Next to traditional communication systems like servers or routers at the backbone and personal computers or laptops acting as clients, the Future Internet will additionally comprise many so-called smart objects. Most of everyday devices like coffee machines, fridges, or light switches will participate in this Internet of Things (IoT).Small-sized computers will connect these devices to the network by establishing low power wireless links. To achieve this vision various kinds of wireless multi-hop networks (WMHNs) play an important role. During the last years, it has become clear that test bed-based research is mandatory in order to develop suitable protocol implementations and metrics for these networks. In this article, we review network configurations for wireless networks for the IoT. We describe the DES-Test bed at the Freie Universitat Berlin as an experimental facility to study these network configurations. In addition to the infrastructure and software provided by the test bed, we introduce μkleos as a micro kernel based operating system for embedded devices. We designed μkleos with a special focus on Wireless Sensor Networks (WSNs) to complement our approach to study WMHNs. μkleos provides an implementation of 6LoWPAN to interconnect WSNs to IP-based networks.
Among several techniques proposed for indoor positioning using IEEE 802.11 Wireless Fidelity (Wi-Fi) based networks, those that rely on fingerprinting have been demonstrated to outperform those based on lateration, an...
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Motivated by our experience from previous testbed-based studies, we discuss the performance of flooding based route discovery schemes. Based on an empirical case study, the limits of routing in IEEE 802.11 wireless mu...
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Motivated by our experience from previous testbed-based studies, we discuss the performance of flooding based route discovery schemes. Based on an empirical case study, the limits of routing in IEEE 802.11 wireless multi-hop networks are highlighted. We show that the route discovery itself can already lead to problems even when there are no or few data flows.
The complexity of pairwise RNA structure alignment depends on the structural restrictions assumed for both the input structures and the computed consensus structure. For arbitrarily crossing input and consensus struct...
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In this paper we present the DES-Chan framework for experimentally-driven research on distributed channel assignment algorithms in wireless mesh networks. The implementation process of channel assignment algorithms is...
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In this paper we present the DES-Chan framework for experimentally-driven research on distributed channel assignment algorithms in wireless mesh networks. The implementation process of channel assignment algorithms is a difficult task for the researcher since common operating systems do not support channel assignment algorithms out of the box. DES-Chan provides a set of common services required by distributed channel assignment algorithms. The modular architecture of DES-Chan allows the extensions with further modules or the modifications of existing ones. As a proof of concept, we present a reference implementation of a distributed greedy channel assignment algorithm. We evaluate its performance in the DES-Testbed, a multi-transceiver wireless mesh network (WMN) with 100 nodes at the Freie Universität Berlin.
The MANIAC Challenge is a competition for cooperation strategies in wireless ad-hoc networks with the focus on experimental evaluation. We present the results of the MANIAC Challenge and discuss characteristics of rea...
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The MANIAC Challenge is a competition for cooperation strategies in wireless ad-hoc networks with the focus on experimental evaluation. We present the results of the MANIAC Challenge and discuss characteristics of real networks such as link instability and mobility, which are often simplified in common network simulators. We introduce our strategy Friendly Clustering that won the Performance Award. Friendly Clustering is based on monitoring the neighbors' forwarding behavior and assessing their willingness to relay future data packets. Further on, we describe the challenges in implementing the strategy for real networks, such as the DES-Testbed at the Freie Universität Berlin and the ad-hoc network of the MANIAC Challenge.
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