The Experts below are selected from a list of 18504 Experts worldwide ranked by ideXlab platform
Giovanna Di Marzo Serugendo - One of the best experts on this subject based on the ideXlab platform.
-
SASO - Towards a Spatial Language for Run-Time Assessments in Self-Organizing Systems
2015 IEEE 9th International Conference on Self-Adaptive and Self-Organizing Systems, 2015Co-Authors: Francesco Luca De Angelis, Giovanna Di Marzo SerugendoAbstract:In this paper we define a spatial language used to verify global properties of Self-Organizing Systems at run-time. The language can be used to assess spatial properties of system components to check desired global properties of the system against emergent global behaviors arising from local interactions among components. The spatial language extends a logic-chemical-based coordination model that we have recently proposed and the verification of spatial properties is performed in a distributed manner among the nodes of the system.
-
SASO Workshops - A Logic Language for Run Time Assessment of Spatial Properties in Self-Organizing Systems
2015 IEEE International Conference on Self-Adaptive and Self-Organizing Systems Workshops, 2015Co-Authors: Francesco Luca De Angelis, Giovanna Di Marzo SerugendoAbstract:The assessment of emergent global behaviors of Self-Organizing applications is an important task to accomplish before employing such Systems in real scenarios, yet their intrinsic complexity make this activity still challenging. In this paper we present a logic language used to verify graph-based global properties of Self-Organizing Systems at run-time. The logic language extends a chemical-based coordination model based on logic inference recently proposed. The logic formulae defined by using the language operators depict the intended global spatial properties arising from local interactions among components. Logic formulae are evaluated in a distributed manner by using an inference procedure which checks them against the current global state of the system, verifying whether the intended emergent global behavior actually appears in the system. As examples of spatial properties we consider color patterns: at first we show how to verify specified patterns of identified colors in sets of nodes directly connected, then we present other formulae verifying the appearance of global patterns of colors without specifying the colors themselves. We conclude the examples with the computation of mathematical functions, like the verification of the existence of a maximum value in a specific node of the system.
-
A method fragments approach to methodologies for engineering Self-Organizing Systems
ACM Transactions on Autonomous and Adaptive Systems, 2012Co-Authors: Mariachiara Puviani, Giovanna Di Marzo Serugendo, Regina Frei, Giacomo CabriAbstract:This article summarizes five relevant methods for developing Self-Organizing multiagent Systems. It identifies their most relevant aspects and provides a description of each one under the form of method fragments expressed using SPEM (Software and System Process Engineering Metamodel). The use of a “metamodel” to describe fragments facilitates the comparison of the methods and their respective fragments. These fragments can be combined and be part of a more general ad hoc methodology, created according to the needs of the designer. Self-Organizing traffic lights controllers and Self-Organizing displays are chosen as case studies to illustrate the methods and to underline which fragments are important for Self-Organizing Systems. Finally, we illustrate how to augment PASSI2, an agent-based methodology which does not consider Self-organization aspects, with some of the identified fragments for Self-organization.
-
robustness and dependability of Self Organizing Systems a safety engineering perspective
International Symposium on Stabilization Safety and Security of Distributed Systems, 2009Co-Authors: Giovanna Di Marzo SerugendoAbstract:This paper analyses the robustness of Self-Organizing (engineered) Systems to perturbations (faults or environmental changes). It considers that a Self-Organizing system is embedded into an environment, the main active building blocks are agents, one or more Self-Organizing mechanisms regulate the interaction among agents, and agents manipulate artifacts, i.e. passive entities maintained by the environment. Perturbations then need to be identified at the level of these four design elements. This paper discusses the boundaries of normal and abnormal behaviour in Self-Organizing Systems and provides guidelines for designers to determine which perturbation in which part of the system leads to a failure.
-
SSS - Robustness and Dependability of Self-Organizing Systems - A Safety Engineering Perspective
Lecture Notes in Computer Science, 2009Co-Authors: Giovanna Di Marzo SerugendoAbstract:This paper analyses the robustness of Self-Organizing (engineered) Systems to perturbations (faults or environmental changes). It considers that a Self-Organizing system is embedded into an environment, the main active building blocks are agents, one or more Self-Organizing mechanisms regulate the interaction among agents, and agents manipulate artifacts, i.e. passive entities maintained by the environment. Perturbations then need to be identified at the level of these four design elements. This paper discusses the boundaries of normal and abnormal behaviour in Self-Organizing Systems and provides guidelines for designers to determine which perturbation in which part of the system leads to a failure.
Wilfried Elmenreich - One of the best experts on this subject based on the ideXlab platform.
-
Evolution as a Tool to Design Self-Organizing Systems
2013Co-Authors: István Fehérvári, Wilfried ElmenreichAbstract:Self-Organizing Systems exhibit numerous advantages such as robustness, adaptivity and scalability, and thus provide a solution for the increasing complexity we face within technical Systems. While they are attractive solutions, due to their nature, designing Self-Organizing Systems is not a straightforward task. Artificial evolution has been proposed as a possible way to build Self-Organizing Systems, but there are still many open questions on how an engineer should apply this method for this purpose. In this paper we propose a design methodology for evolving Self-Organizing Systems, that marks the major cornerstones and decisions the designer has to face, thus providing a practical set of guidelines.
-
IWSOS - Evolution as a Tool to Design Self-Organizing Systems
Self-Organizing Systems, 2013Co-Authors: István Fehérvári, Wilfried ElmenreichAbstract:Self-Organizing Systems exhibit numerous advantages such as robustness, adaptivity and scalability, and thus provide a solution for the increasing complexity we face within technical Systems. While they are attractive solutions, due to their nature, designing Self-Organizing Systems is not a straightforward task. Artificial evolution has been proposed as a possible way to build Self-Organizing Systems, but there are still many open questions on how an engineer should apply this method for this purpose. In this paper we propose a design methodology for evolving Self-Organizing Systems, that marks the major cornerstones and decisions the designer has to face, thus providing a practical set of guidelines.
-
frevo a tool for evolving and evaluating Self Organizing Systems
Self-Adaptive and Self-Organizing Systems, 2012Co-Authors: Anita Sobe, István Fehérvári, Wilfried ElmenreichAbstract:Typically, Self-Organizing Systems comprise of a large number of individual agents whose behavior needs to be controlled by a set of parameters so that their interactions lead to the creation of the desired system. To be Self-Organizing, the system must mimic the evolutionary process. One way to do this is by use of an evolutionary algorithm. This mimics naturally-occurring genetic variation (mutation and recombination of genes). To fulfill this purpose, we have created a tool named FREVO (FRamework for EVOlutionary design), which separates the input needed into the following components: target problem evaluation, controller representation and the optimization method. FREVO provides well-defined interfaces for these components and supports a graphical user interface to simulate the evolutionary process. After obtaining the outcome for a simulation, it is possible to validate and evaluate the results within FREVO. FREVO has been successfully applied to various problems, from cooperative robotics to economics, pattern generation and wireless sensor networks. In this paper, we give an overview of the architecture of FREVO and introduce a case study involving smart grid networks.
-
How to Design Self-Organizing Systems?
2009Co-Authors: Wilfried Elmenreich, Gerhard FriedrichAbstract:The behavior of a Self-Organizing system (SOS) is typically defined by the local interaction rules of the components. While this emergent behavior typically is very flexible, i.e., working at different scales being robust against disturbances and failures, there exists no straight-forward way for the design of these rules so that the overall system shows the desired properties. The try and error methods, even when being improved using notions such as the ”friction” between two components often suffer from counter-intuitive interrelationships between local rules and emergent behavior. Imitation approaches, such as the bio-inspired methods or the programming of the local behavior by analyzing an example using perfect knowledge are limited to the cases where an appropriate example model is available. Therefore, we investigate on novel generic approaches for designing SelfOrganizing Systems. E. g., promising methods could be genetic algorithms or particle swarm optimization methods. A possible approach to model the local interaction in a way that can be evolved is given by neural networks. In the long term, we aim at a generic optimization tool for designing and exploring rulesets for SOS designs.
-
Self Organizing networked Systems for technical applications a discussion on open issues
International Workshop on Self-Organizing Systems, 2008Co-Authors: Wilfried Elmenreich, Hermann De MeerAbstract:The concept of Self-organization has been examined oftentimes for several domains such as physics, chemistry, mathematics, etc. However, the current technical development opens a new field of Self-Organizing applications by creating Systems of networked and massively distributed hardware with Self-organized control. Having this view in mind, this papers reviews the questions: What is a Self-Organizing system?, What is it not?, Should there be a separate field of science for Self-Organizing Systems? , and What are possible approaches to engineer a Self-Organizing control system? . The presented ideas have been elaborated at the Lakeside Research Days'08 (University of Klagenfurt, Austria), a workshop that featured guided discussions between invited experts working in the field of Self-Organizing Systems.
Wolfgang Reif - One of the best experts on this subject based on the ideXlab platform.
-
runtime model based safety analysis of Self Organizing Systems with s
Self-Adaptive and Self-Organizing Systems, 2015Co-Authors: Axel Habermaier, Benedikt Eberhardinger, Hella Seebach, Johannes Leupolz, Wolfgang ReifAbstract:Self-Organizing Systems present a challenge for model-based safety analysis techniques: At design time, the potential system configurations are unknown, making it necessary to postpone the safety analyses to runtime. At runtime, however, model checking based safety analysis techniques are often too time-consuming because of the large state spaces that have to be analyzed. Based on the S# framework's support for runtime model adaptation, we modularize runtime safety analyses by splitting them into two parts, modeling and analyzing the Self-Organizing and non-Self-Organizing parts separately. With some additional heuristics, the resulting state space reduction facilitates the use of model checking based safety analysis techniques to analyze the safety of Self-Organizing Systems. We outline this approach on a Self-Organizing production cell, assessing the Self-organization's impact on the overall safety of the system.
-
SASO Workshops - Runtime Model-Based Safety Analysis of Self-Organizing Systems with S#
2015 IEEE International Conference on Self-Adaptive and Self-Organizing Systems Workshops, 2015Co-Authors: Axel Habermaier, Benedikt Eberhardinger, Hella Seebach, Johannes Leupolz, Wolfgang ReifAbstract:Self-Organizing Systems present a challenge for model-based safety analysis techniques: At design time, the potential system configurations are unknown, making it necessary to postpone the safety analyses to runtime. At runtime, however, model checking based safety analysis techniques are often too time-consuming because of the large state spaces that have to be analyzed. Based on the S# framework's support for runtime model adaptation, we modularize runtime safety analyses by splitting them into two parts, modeling and analyzing the Self-Organizing and non-Self-Organizing parts separately. With some additional heuristics, the resulting state space reduction facilitates the use of model checking based safety analysis techniques to analyze the safety of Self-Organizing Systems. We outline this approach on a Self-Organizing production cell, assessing the Self-organization's impact on the overall safety of the system.
-
Trust-Based Scenarios – Predicting Future Agent Behavior in Open Self-Organizing Systems
2013Co-Authors: Gerrit Anders, Florian Siefert, Jan-philipp Steghöfer, Wolfgang ReifAbstract:Agents in open Self-Organizing Systems have to cope with a variety of uncertainties. In order to increase their utility and to ensure stable operation of the overall system, they have to capture and adapt to these uncertainties at runtime. This can be achieved by formulating an expectancy of the behavior of others and the environment. Trust has been proposed as a concept for this purpose.In this paper, we present trust-based scenarios as an enhancement of current trust models. Trust-based scenarios represent stochastic models that allow agents to take different possible developments of the environment’s or other agents’ behavior into account. We demonstrate that trust-based scenarios significantly improve the agents’ capability to predict future behavior with a distributed power management application.
Sajeev John - One of the best experts on this subject based on the ideXlab platform.
-
photonic bandgap formation and tunability in certain Self Organizing Systems
Journal of Lightwave Technology, 1999Co-Authors: Sajeev John, Kurt BuschAbstract:We describe the microfabrication and band structure of large scale three-dimensional (3D) photonic bandgap (PBG) materials based on Self-Organizing templates. The simplest of these templates is an fcc lattice of close-packed, weakly sintered spheres. Other templates include hcp and hexagonal AB/sub 2/ Self-Organizing photonic crystals. These photonic crystals may be converted into PEG materials by partially infiltrating the template with high refractive index semiconductors such as Si, Ge, or GaP and subsequently removing the template. The resulting "inverse opal" structure exhibits both a photonic pseudogap and a complete (3D) PBG in the near visible spectrum, spanning up to 15% of the gap center frequency. The local density of states (LDOS) for photons exhibits considerable variation from point to point in coordinate space and reveals large spectral gaps even in the absence of a PEG in the total density of states. These gaps in the LDOS may lead to novel effects in quantum and nonlinear optics when active atoms or molecules are placed within the PBG material. These effects include anomalous, low threshold nonlinear response, collective atomic switching, and low-threshold all-optical transistor action. When an optically birefringent nematic liquid crystal is infiltrated into the void regions of the "inverse" opal PBG material, the resulting composite material exhibits a completely tunable PBG. In particular, the 3D PBG can be completely opened or closed by applying an electric field which rotates the axis of the nematic molecules relative to the inverse opal backbone.
-
photonic band gap formation in certain Self Organizing Systems
Physical Review E, 1998Co-Authors: Kurt Busch, Sajeev JohnAbstract:We present a detailed study of photonic band structure in certain Self-Organizing Systems that Self-assemble into large-scale photonic crystals with photonic band gaps (PBGs) or pseudogaps in the near-visible frequency regime. These include colloidal suspensions, inverted opals, and macroporous silicon. We show that complete three-dimensional PBGs spanning roughly 10% and 15% of the gap center frequency are attainable by incomplete infiltration of an opal with silicon and germanium, respectively. The photonic band structure of both face center cubic and hexagonal close packed photonic crystals are evaluated. We delineate how the PBG is modified by sintering the opal prior to infiltration and by applying strain along various crystallographic directions. We evaluate the total photon density of states as well as the local density of states (LDOS) projected onto various points within the photonic crystal. It is shown that the LDOS may exhibit considerable pseudogap structure even for Systems that do not exhibit a complete PBG. These results are directly relevant to quantum optical experiments in which atoms, dye molecules, or other active materials are inserted into specific locations within the photonic crystal. When the resonant optical transition of these dopants is tuned close to a pseudogap or other abrupt structure in the LDOS, novel effects in radiative dynamics associated with a ``colored vacuum'' may be realized.
Kurt Busch - One of the best experts on this subject based on the ideXlab platform.
-
photonic bandgap formation and tunability in certain Self Organizing Systems
Journal of Lightwave Technology, 1999Co-Authors: Sajeev John, Kurt BuschAbstract:We describe the microfabrication and band structure of large scale three-dimensional (3D) photonic bandgap (PBG) materials based on Self-Organizing templates. The simplest of these templates is an fcc lattice of close-packed, weakly sintered spheres. Other templates include hcp and hexagonal AB/sub 2/ Self-Organizing photonic crystals. These photonic crystals may be converted into PEG materials by partially infiltrating the template with high refractive index semiconductors such as Si, Ge, or GaP and subsequently removing the template. The resulting "inverse opal" structure exhibits both a photonic pseudogap and a complete (3D) PBG in the near visible spectrum, spanning up to 15% of the gap center frequency. The local density of states (LDOS) for photons exhibits considerable variation from point to point in coordinate space and reveals large spectral gaps even in the absence of a PEG in the total density of states. These gaps in the LDOS may lead to novel effects in quantum and nonlinear optics when active atoms or molecules are placed within the PBG material. These effects include anomalous, low threshold nonlinear response, collective atomic switching, and low-threshold all-optical transistor action. When an optically birefringent nematic liquid crystal is infiltrated into the void regions of the "inverse" opal PBG material, the resulting composite material exhibits a completely tunable PBG. In particular, the 3D PBG can be completely opened or closed by applying an electric field which rotates the axis of the nematic molecules relative to the inverse opal backbone.
-
photonic band gap formation in certain Self Organizing Systems
Physical Review E, 1998Co-Authors: Kurt Busch, Sajeev JohnAbstract:We present a detailed study of photonic band structure in certain Self-Organizing Systems that Self-assemble into large-scale photonic crystals with photonic band gaps (PBGs) or pseudogaps in the near-visible frequency regime. These include colloidal suspensions, inverted opals, and macroporous silicon. We show that complete three-dimensional PBGs spanning roughly 10% and 15% of the gap center frequency are attainable by incomplete infiltration of an opal with silicon and germanium, respectively. The photonic band structure of both face center cubic and hexagonal close packed photonic crystals are evaluated. We delineate how the PBG is modified by sintering the opal prior to infiltration and by applying strain along various crystallographic directions. We evaluate the total photon density of states as well as the local density of states (LDOS) projected onto various points within the photonic crystal. It is shown that the LDOS may exhibit considerable pseudogap structure even for Systems that do not exhibit a complete PBG. These results are directly relevant to quantum optical experiments in which atoms, dye molecules, or other active materials are inserted into specific locations within the photonic crystal. When the resonant optical transition of these dopants is tuned close to a pseudogap or other abrupt structure in the LDOS, novel effects in radiative dynamics associated with a ``colored vacuum'' may be realized.