A compositional method for reliability analysis of workflows affected by multiple failure modes

We focus on reliability analysis for systems designed as workflow based compositions of components. Components are characterized by their failure profiles, which take into account possible multiple failure modes. A compositional calculus is provided to evaluate the failure profile of a composite system, given failure profiles of the components. The calculus is described as a syntax-driven procedure that synthesizes a workflows failure profile. The method is viewed as a design-time aid that can help software engineers reason about systems reliability in the early stage of development. A simple case study is presented to illustrate the proposed approach

Enterprise Modelling using Algebraic Graph Transformation - Extended Version

An analysis of today's situation at Credit Suisse has shown severe problems, because it is based on current best practices and ad-hoc modelling techniques to handle important aspects of security, risk and compliance. Based on this analysis we propose in this paper a new enterprise model which allows the construction, integration, transformation and evaluation of different organizational models in a big decentralized organization like Credit Suisse. The main idea of the new model framework is to provide small decentralized models and intra-model evaluation techniques to handle services, processes and rules separately for the business and IT universe on one hand and for human-centric and machine-centric concepts on the other hand. Furthermore, the new framework provides inter-modelling techniques based on algebraic graph transformation to establish the connection between different kinds of models and to allow integration of the decentralized models. In order to check for security, risk and compliance in a suitable way, our models and techniques are based on different kinds of formal methods. In this paper, we show that algebraic graph transformation techniques are useful not only for intra-modelling - using graph grammars for visual languages and graph constraints for requirements - but also for inter-modelling - using triple graph grammars for model transformation and integration. Altogether, we present the overall idea of our new model framework and show how to solve specific problems concerning intra- and inter-modelling as first steps. This should give evidence that our framework can also handle important other requirements for enterprise modelling in a big decentralized organization like Credit Suisse

A Language and Hardware Independent Approach to Quantum-Classical Computing

Heterogeneous high-performance computing (HPC) systems offer novel architectures which accelerate specific workloads through judicious use of specialized coprocessors. A promising architectural approach for future scientific computations is provided by heterogeneous HPC systems integrating quantum processing units (QPUs). To this end, we present XACC (eXtreme-scale ACCelerator) --- a programming model and software framework that enables quantum acceleration within standard or HPC software workflows. XACC follows a coprocessor machine model that is independent of the underlying quantum computing hardware, thereby enabling quantum programs to be defined and executed on a variety of QPUs types through a unified application programming interface. Moreover, XACC defines a polymorphic low-level intermediate representation, and an extensible compiler frontend that enables language independent quantum programming, thus promoting integration and interoperability across the quantum programming landscape. In this work we define the software architecture enabling our hardware and language independent approach, and demonstrate its usefulness across a range of quantum computing models through illustrative examples involving the compilation and execution of gate and annealing-based quantum programs

The Urban Toolkit: A Grammar-based Framework for Urban Visual Analytics

While cities around the world are looking for smart ways to use new advances in data collection, management, and analysis to address their problems, the complex nature of urban issues and the overwhelming amount of available data have posed significant challenges in translating these efforts into actionable insights. In the past few years, urban visual analytics tools have significantly helped tackle these challenges. When analyzing a feature of interest, an urban expert must transform, integrate, and visualize different thematic (e.g., sunlight access, demographic) and physical (e.g., buildings, street networks) data layers, oftentimes across multiple spatial and temporal scales. However, integrating and analyzing these layers require expertise in different fields, increasing development time and effort. This makes the entire visual data exploration and system implementation difficult for programmers and also sets a high entry barrier for urban experts outside of computer science. With this in mind, in this paper, we present the Urban Toolkit (UTK), a flexible and extensible visualization framework that enables the easy authoring of web-based visualizations through a new high-level grammar specifically built with common urban use cases in mind. In order to facilitate the integration and visualization of different urban data, we also propose the concept of knots to merge thematic and physical urban layers. We evaluate our approach through use cases and a series of interviews with experts and practitioners from different domains, including urban accessibility, urban planning, architecture, and climate science. UTK is available at urbantk.org.Comment: Accepted at IEEE VIS 2023. UTK is available at http://urbantk.or

RONs Revisited: General Approach to Model Reconfigurable Object Nets based on Algebraic High-Level Nets

Reconfigurable Object Nets (RONs) have been implemented in our group to support the visual specification of controlled rule-based transformations of marked place/transition (P/T) nets. RONs are high-level nets (system nets) with two types of tokens: object nets (P/T nets) and net transformation rules. System net transitions can be of different types to fire object net transitions, move object nets through the system net, or to apply a net transformation rule to an object net. The disadvantage of the RON approach and tool is the limitation of object nets to P/T nets and the limitation of the underlying semantics of RONs due to the fixed types for system net transitions. Often, a more general approach is preferred where the type of object nets and the behavior of reconfigurations may be defined in a more flexible way. In this paper, we propose to use Algebraic High-Level nets with individual tokens (AHLI nets) as system nets. In this more general approach, tokens may be any type of Petri nets, defined by the corresponding algebraic signature and algebra. To support this general approach, a development environment for AHLI nets is currently implemented which allows the user to edit and simulate AHLI nets. We present the formalization of RONs as special AHLI nets and describe the current state of the AHLI net tool environment

Web service composition: A survey of techniques and tools

Web services are a consolidated reality of the modern Web with tremendous, increasing impact on everyday computing tasks. They turned the Web into the largest, most accepted, and most vivid distributed computing platform ever. Yet, the use and integration of Web services into composite services or applications, which is a highly sensible and conceptually non-trivial task, is still not unleashing its full magnitude of power. A consolidated analysis framework that advances the fundamental understanding of Web service composition building blocks in terms of concepts, models, languages, productivity support techniques, and tools is required. This framework is necessary to enable effective exploration, understanding, assessing, comparing, and selecting service composition models, languages, techniques, platforms, and tools. This article establishes such a framework and reviews the state of the art in service composition from an unprecedented, holistic perspective

Automatic building information model query generation

Energy efficient building design and construction calls for extensive collaboration between different subfields of the Architecture, Engineering and Construction (AEC) community. Performing building design and construction engineering raises challenges on data integration and software interoperability. Using Building Information Modeling (BIM) data hub to host and integrate building models is a promising solution to address those challenges, which can ease building design information management. However, the partial model query mechanism of current BIM data hub collaboration model has several limitations, which prevents designers and engineers to take advantage of BIM. To address this problem, we propose a general and effective approach to generate query code based on a Model View Definition (MVD). This approach is demonstrated through a software prototype called QueryGenerator. By demonstrating a case study using multi-zone air flow analysis, we show how our approach and tool can help domain experts to use BIM to drive building design with less labour and lower overhead cost.published_or_final_versio