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71.
72.
Mischa Schmidt Jan Seedorf Stefano Napolitano Rosario G. Garroppo Andrea Cavaliere Thilo Ewald Armin Jahanpanah Zbigniew Kopertowski Marcin Pilarski Pawel Grochocki 《Peer-to-Peer Networking and Applications》2013,6(2):134-154
Application Layer Traffic Optimization (ALTO) has recently gained attention in the research and standardisation community as a way for a network operator to guide the peer selection process of distributed applications by providing network layer topology information. In particular P2P applications are expected to gain from ALTO, due to the many connections peers form among each other, often without taking network layer topology information into account. In this paper, we present results of an extensive intra-ISP trial with an ALTO-enhanced P2P filesharing software. In summary, our results show that—depending on the concrete setting and on the distribution of upload capacity in the network—ALTO enables an ISP to save operational costs significantly while not degrading application layer performance noticeably. In addition, based on our experience we are able to give advice to operators on how to save costs with ALTO while not sacrificing application layer performance at all. 相似文献
73.
We report image blurring and energy broadening effects in energy-filtered XPEEM when illuminating the specimen with soft X-rays at high flux densities. With a flux of 2×1013 photons/s, the lateral resolution in XPEEM imaging with either core level or secondary electrons is degraded to more than 50 nm. Fermi level broadening up to several hundred meV and spectral shift to higher kinetic energies are also systematically observed. Simple considerations suggest that these artifacts result from Boersch and Loeffler effects, and that the electron-electron interactions are strongest in the initial part of the microscope optical path. Implications for aberration corrected instruments are discussed. 相似文献
74.
Julia Heidemann Mathias Klier Andrea Landherr Steffen Zimmermann 《Electronic Markets》2013,23(1):73-84
In light of the growing relevance of customer-oriented business strategies IT investments in the field of Customer Relationship Management have increased considerably. However, firms often could not realize sufficient returns on these IT investments. One major reason for this failure seems to be the lack of appropriate approaches to determine the economic impact of such investments ex ante. Therefore, we develop an economic model to determine the optimal level of Customer Relationship Management IT investments. Using this approach, firms can evaluate, to what extent investments in Customer Relationship Management IT are reasonable. One major result is that in most cases the “all or nothing strategy” pursued by many firms does not lead to the optimal level of investments. To illustrate the practical utility and applicability of the approach, we provide a real world example of a German financial services provider. 相似文献
75.
This paper addresses the design of low‐level controllers for leader–follower formations of nonholonomic vehicles in the presence of bounded measurement delays. The concept of input‐to‐state stability is extended to encompass the effect of bounded delays and restrictions on the input. A method is proposed to integrate a Smith predictor in a backstepping design on the basis of nested saturations and nonlinear small‐gain assignment, which allows for time delays in the feedback loop. Robustness analysis under uncertain bounded time delays is provided, and design tradeoffs resulting from the use of bounded controls are discussed. Illustrative simulations are shown to validate the design and robustness analysis in the context of a simple leader–follower trailing control problem. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
76.
Fabio Poiesi Riccardo Mazzon Andrea Cavallaro 《Computer Vision and Image Understanding》2013,117(10):1257-1272
We propose a generic online multi-target track-before-detect (MT-TBD) that is applicable on confidence maps used as observations. The proposed tracker is based on particle filtering and automatically initializes tracks. The main novelty is the inclusion of the target ID in the particle state, enabling the algorithm to deal with unknown and large number of targets. To overcome the problem of mixing IDs of targets close to each other, we propose a probabilistic model of target birth and death based on a Markov Random Field (MRF) applied to the particle IDs. Each particle ID is managed using the information carried by neighboring particles. The assignment of the IDs to the targets is performed using Mean-Shift clustering and supported by a Gaussian Mixture Model. We also show that the computational complexity of MT-TBD is proportional only to the number of particles. To compare our method with recent state-of-the-art works, we include a postprocessing stage suited for multi-person tracking. We validate the method on real-world and crowded scenarios, and demonstrate its robustness in scenes presenting different perspective views and targets very close to each other. 相似文献
77.
Many software engineering problems have been addressed with search algorithms. Search algorithms usually depend on several parameters (e.g., population size and crossover rate in genetic algorithms), and the choice of these parameters can have an impact on the performance of the algorithm. It has been formally proven in the No Free Lunch theorem that it is impossible to tune a search algorithm such that it will have optimal settings for all possible problems. So, how to properly set the parameters of a search algorithm for a given software engineering problem? In this paper, we carry out the largest empirical analysis so far on parameter tuning in search-based software engineering. More than one million experiments were carried out and statistically analyzed in the context of test data generation for object-oriented software using the EvoSuite tool. Results show that tuning does indeed have impact on the performance of a search algorithm. But, at least in the context of test data generation, it does not seem easy to find good settings that significantly outperform the “default” values suggested in the literature. This has very practical value for both researchers (e.g., when different techniques are compared) and practitioners. Using “default” values is a reasonable and justified choice, whereas parameter tuning is a long and expensive process that might or might not pay off in the end. 相似文献
78.
Elena Baralis Andrea Bianco Tania Cerquitelli Luca Chiaraviglio Marco Mellia 《Computer Networks》2013,57(17):3300-3315
Internet measured data collected via passive measurement are analyzed to obtain localization information on nodes by clustering (i.e., grouping together) nodes that exhibit similar network path properties. Since traditional clustering algorithms fail to correctly identify clusters of homogeneous nodes, we propose the NetCluster novel framework, suited to analyze Internet measurement datasets. We show that the proposed framework correctly analyzes synthetically generated traces. Finally, we apply it to real traces collected at the access link of Politecnico di Torino campus LAN and discuss the network characteristics as seen at the vantage point. 相似文献
79.
Andrea Caiti Vincenzo Calabrò Andrea Munafò Gianluca Dini Angelica Lo Duca 《野外机器人技术杂志》2013,30(2):237-253
The EU‐funded project UAN (Underwater Acoustic Network) was aimed at conceiving, developing, and testing at sea an innovative and operational concept for integrating underwater and above‐water sensors in a unique communication system to protect offshore and coastline critical infrastructures. This work gives details on the underwater part of the project. It introduces a set of original security features and gives details on the integration of autonomous underwater vehicles (AUVs) as mobile nodes of the network and as surveillance assets, acoustically controlled by the command and control center to respond against intrusions. Field results are given of the final UAN project sea trial, UAN11, held in May 2011 in Norway. During the experimental activities, a UAN composed of four fixed nodes, two AUVs, and one mobile node mounted on the supporting research vessel was operated continuously and integrated into a global protection system. In this article, the communication performance of the network is reported in terms of round‐trip time, packet loss, and average delivery ratio. The major results of the experiment can be thus summarized: the implemented network structure was successful in continuously operating over five days with nodes seamlessly entering and exiting the network; the performance of the network varied greatly with fluctuations in the acoustic channel; the addition of security features induced a minor degradation in network performance with respect to channel variation; the AUVs were successfully controlled from a remote station through acoustic signals routed by the network. © 2013 Wiley Periodicals, Inc. 相似文献
80.
This paper addresses the problem of fault detection and isolation for a particular class of discrete event dynamical systems
called hierarchical finite state machines (HFSMs). A new version of the property of diagnosability for discrete event systems
tailored to HFSMs is introduced. This notion, called L1-diagnosability, captures the possibility of detecting an unobservable fault event using only high level observations of the
behavior of an HFSM. Algorithms for testing L1-diagnosability are presented. In addition, new methodologies are presented for studying the diagnosability properties of
HFSMs that are not L1-diagnosable. These methodologies avoid the complete expansion of an HFSM into its corresponding flat automaton by focusing
the expansion on problematic indeterminate cycles only in the associated extended diagnoser.
Andrea Paoli received the master degree in Computer Science Engineering and the Ph.D. in Automatic Control and Operational Research from the University of Bologna in 2000 and 2003 respectively. He currently holds a Post Doc position at the Department of Electronics, Computer Science and Systems (DEIS) at the University of Bologna, Italy. He is a member of the Center for Research on Complex Automated Systems (CASY) Giuseppe Evangelisti. From August to January 2002, and in March 2005 he held visiting positions at the Department of Electrical Engineering and Computer Science at The University of Michigan, Ann Arbor. In July 2005 he won the prize IFAC Outstanding AUTOMATICA application paper award for years 2002-2005 for the article by Claudio Bonivento, Alberto Isidori, Lorenzo Marconi, Andrea Paoli titled Implicit fault-tolerant control: application to induction motors appeared on AUTOMATICA issue 30(4). Since 2006 he is a member of the IFAC Technical Committee on Fault Detection, Supervision and Safety of Technical Processes (IFAC SAFEPROCESS TC). His current research interests focus on Fault Tolerant Control and Fault Diagnosis in distributed systems and in discrete event systems and on industrial automation software architectures following an agent based approach. His theoretical background includes also nonlinear control and output regulation using geometric approach. Stéphane Lafortune received the B. Eng degree from Ecole Polytechnique de Montréal in 1980, the M. Eng. degree from McGill University in 1982, and the Ph.D. degree from the University of California at Berkeley in 1986, all in electrical engineering. Since September 1986, he has been with the University of Michigan, Ann Arbor, where he is a Professor of Electrical Engineering and Computer Science. Dr. Lafortune is a Fellow of the IEEE (1999). He received the Presidential Young Investigator Award from the National Science Foundation in 1990 and the George S. Axelby Outstanding Paper Award from the Control Systems Society of the IEEE in 1994 (for a paper co-authored with S. L. Chung and F. Lin) and in 2001 (for a paper co-authored with G. Barrett). At the University of Michigan, he received the EECS Department Research Excellence Award in 1994–1995, the EECS Department Teaching Excellence Award in 1997–1998, and the EECS Outstanding Achievement Award in 2003–2004. Dr. Lafortune is a member of the editorial boards of the Journal of Discrete Event Dynamic Systems: Theory and Applications and of the International Journal of Control. His research interests are in discrete event systems modeling, diagnosis, control, and optimization. He is co-developer of the software packages DESUMA and UMDES. He co-authored, with C. Cassandras, the textbook Introduction to Discrete Event Systems—Second Edition (Springer, 2007). Recent publications and software tools are available at the Web site . 相似文献
Stéphane LafortuneEmail: |
Andrea Paoli received the master degree in Computer Science Engineering and the Ph.D. in Automatic Control and Operational Research from the University of Bologna in 2000 and 2003 respectively. He currently holds a Post Doc position at the Department of Electronics, Computer Science and Systems (DEIS) at the University of Bologna, Italy. He is a member of the Center for Research on Complex Automated Systems (CASY) Giuseppe Evangelisti. From August to January 2002, and in March 2005 he held visiting positions at the Department of Electrical Engineering and Computer Science at The University of Michigan, Ann Arbor. In July 2005 he won the prize IFAC Outstanding AUTOMATICA application paper award for years 2002-2005 for the article by Claudio Bonivento, Alberto Isidori, Lorenzo Marconi, Andrea Paoli titled Implicit fault-tolerant control: application to induction motors appeared on AUTOMATICA issue 30(4). Since 2006 he is a member of the IFAC Technical Committee on Fault Detection, Supervision and Safety of Technical Processes (IFAC SAFEPROCESS TC). His current research interests focus on Fault Tolerant Control and Fault Diagnosis in distributed systems and in discrete event systems and on industrial automation software architectures following an agent based approach. His theoretical background includes also nonlinear control and output regulation using geometric approach. Stéphane Lafortune received the B. Eng degree from Ecole Polytechnique de Montréal in 1980, the M. Eng. degree from McGill University in 1982, and the Ph.D. degree from the University of California at Berkeley in 1986, all in electrical engineering. Since September 1986, he has been with the University of Michigan, Ann Arbor, where he is a Professor of Electrical Engineering and Computer Science. Dr. Lafortune is a Fellow of the IEEE (1999). He received the Presidential Young Investigator Award from the National Science Foundation in 1990 and the George S. Axelby Outstanding Paper Award from the Control Systems Society of the IEEE in 1994 (for a paper co-authored with S. L. Chung and F. Lin) and in 2001 (for a paper co-authored with G. Barrett). At the University of Michigan, he received the EECS Department Research Excellence Award in 1994–1995, the EECS Department Teaching Excellence Award in 1997–1998, and the EECS Outstanding Achievement Award in 2003–2004. Dr. Lafortune is a member of the editorial boards of the Journal of Discrete Event Dynamic Systems: Theory and Applications and of the International Journal of Control. His research interests are in discrete event systems modeling, diagnosis, control, and optimization. He is co-developer of the software packages DESUMA and UMDES. He co-authored, with C. Cassandras, the textbook Introduction to Discrete Event Systems—Second Edition (Springer, 2007). Recent publications and software tools are available at the Web site . 相似文献