@inbook {18024, title = {Modeling Responsiveness of Decentralized Service Discovery in Wireless Mesh Networks}, booktitle = {MMB \& DFT}, series = {Lecture Notes in Computer Science}, volume = {8376}, year = {2014}, pages = {88-102}, publisher = {Springer International Publishing Switzerland}, organization = {Springer International Publishing Switzerland}, abstract = {In modern service networks, discovery plays a crucial role as a layer where providing instances of a given service can be published and enumerated. Since successful discovery is mandatory for service usage, comprehensive service dependability assessment needs to incorporate the dependability of the discovery layer. This work focuses on the responsiveness of the discovery layer, the probability to operate successfully within a deadline, even in the presence of faults. It proposes a hierarchy of stochastic models for decentralized discovery and uses it to describe the discovery of a single service using three well-known discovery protocols: domain name system based service discovery (DNS-SD), simple service discovery protocol (SSDP) and service location protocol (SLP). Further, a methodology to use the model hierarchy in wireless mesh networks is introduced. Given a pair service requester and provider, a discovery protocol and a deadline, it estimates packet loss probabilities and transmission time distributions for each link on the communication paths between the pair, generates specific model instances and calculates the expected responsiveness. Finally, the paper introduces a new metric, the expected responsiveness distance d_er to estimate the maximum distance from a provider where requesters are still able to discover it with a required responsiveness. The models and their methodology are demonstrated using monitoring data from the distributed embedded systems (DES) testbed at Freie Universit{\"a}t Berlin. It is shown how the responsiveness and d_er of the protocols change depending on the position of requester and provider and the overall link quality in the network.}, keywords = {fault tolerance, Markov Models, Real time systems, Responsiveness, Service Discovery, Wireless mesh networks}, isbn = {978-3-319-05358-5}, issn = {0302-9743}, doi = {10.1007/978-3-319-05359-2_7}, url = {http://andreas-dittrich.eu/2013/12/modeling-responsiveness-of-decentralized-service-discovery-in-wireless-mesh-networks}, author = {Dittrich, Andreas and Lichtblau, Bj{\"o}rn and Rezende, Rafael and Malek, Miroslaw}, editor = {Fischbach, K. and Krieger, U. R.} } @conference {17729, title = {A Model for the Evaluation of User-Perceived Service Properties}, booktitle = {International Symposium on Parallel Distributed Processing, Workshops and Phd Forum (IPDPSW)}, year = {2013}, month = {May}, publisher = {IEEE Computer Society}, organization = {IEEE Computer Society}, address = {Boston, Massachusetts, USA}, abstract = {An ever-increasing number of both functional and non-functional requirements has resulted in growing system complexity which demands new solutions in system modeling and evaluation. As a remedy, service-oriented architecture (SOA) offers services as basic building elements of system design. Service dependability is highly dependent on the properties of the underlying information and communications technology (ICT) infrastructure. This is especially true for the user-perceived dependability of a specific pair service client and provider as every pair may utilize different ICT components. We provide a model for the description of ICT components and their non-functional properties based on the Unified Modeling Language (UML). Given a service description, a network topology model and a pair service client and provider, we propose a methodology to automatically identify relevant ICT components and generate a user-perceived service infrastructure model (UPSIM). We demonstrate the feasibility of the methodology by applying it to parts of the service network infrastructure at Universit{\`a} della Svizzera italiana, Switzerland. We then show how this methodology can be used to facilitate user-perceived service dependability analysis.}, keywords = {availability, design engineering, metamodeling, modeling, object oriented modeling, quality of service (QoS), service dependability, service network management, service networks}, isbn = {978-0-7695-4979-8}, doi = {10.1109/IPDPSW.2013.163}, url = {http://andreas-dittrich.eu/2013/03/a-model-for-the-evaluation-of-user-perceived-service-properties}, author = {Dittrich, Andreas and Kaitovi{\'c}, Igor and Murillo, Cristina and Rezende, Rafael} } @inbook {17731, title = {Model-Driven Evaluation of User-Perceived Service Availability}, booktitle = {Dependable Computing}, series = {Lecture Notes in Computer Science}, volume = {7869}, year = {2013}, month = {May}, pages = {39-53}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, abstract = {Service-oriented architecture (SOA), which proposes services as basic building elements of system design, has emerged as an approach to master growing system complexity. However, it remains difficult to evaluate dependability of such distributed and heterogeneous functionality as it depends highly on the properties of the enabling information and communications technology (ICT) infrastructure. Moreover, every specific pair service client and provider can utilize different ICT components, constituting for the user-perceived view of a service. We provide a model-driven methodology to automatically create reliability block diagrams of such views. Given a service description, a network topology model and a pair service client and provider, it identifies relevant ICT components and generates a user-perceived service availability model (UPSAM). We then use this UPSAM to calculate the steady-state availability of different views on an examplary mail service deployed in the network infrastructure of University of Lugano.}, keywords = {availability, design engineering, modeling, object oriented modeling, quality of service (QoS), service dependability, service network management, service networks}, issn = {978-3-642-38788-3}, doi = {10.1007/978-3-642-38789-0_4}, url = {http://andreas-dittrich.eu/2013/04/model-driven-evaluation-of-user-perceived-service-availability}, author = {Dittrich, Andreas and Rezende, Rafael}, editor = {Vieira, Marco and Cunha, Jo{\~a}o Carlos} }