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Egon Borger - One of the best experts on this subject based on the ideXlab platform.
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abstract state machines a method for high level system design and analysis
2003Co-Authors: Egon Borger, Robert F StarkAbstract:1 Introduction.- 1.1 Goals of the Book and Contours of its Method.- 1.1.1 Stepwise Refinable Abstract Operational Modeling.- 1.1.2 Abstract Virtual Machine Notation.- 1.1.3 Practical Benefits.- 1.1.4 Harness Pseudo-Code by Abstraction and Refinement.- 1.1.5 Adding Abstraction and Rigor to UML Models.- 1.2 Synopsis of the Book.- 2 ASM Design and Analysis Method.- 2.1 Principles of Hierarchical System Design.- 2.1.1 Ground Model Construction (Requirements Capture).- 2.1.2 Stepwise Refinement (Incremental Design).- 2.1.3 Integration into Software Practice.- 2.2 Working Definition.- 2.2.1 Basic ASMs.- 2.2.2 Definition.- 2.2.3 Classification of Locations and Updates.- 2.2.4 ASM Modules.- 2.2.5 Illustration by Small Examples.- 2.2.6 Control State ASMs.- 2.2.7 Exercises.- 2.3 Explanation by Example: Correct Lift Control.- 2.3.1 Exercises.- 2.4 Detailed Definition (Math. Foundation).- 2.4.1 Abstract States and Update Sets.- 2.4.2 Mathematical Logic.- 2.4.3 Transition Rules and Runs of ASMs.- 2.4.4 The Reserve of ASMs.- 2.4.5 Exercises.- 2.5 Notational Conventions.- 3 Basic ASMs.- 3.1 Requirements Capture by Ground Models.- 3.1.1 Fundamental Questions to be Asked.- 3.1.2 Illustration by Small Use Case Models.- 3.1.3 Exercises.- 3.2 Incremental Design by Refinements.- 3.2.1 Refinement Scheme and its Specializations.- 3.2.2 Two Refinement Verification Case Studies.- 3.2.3 Decomposing Refinement Verifications.- 3.2.4 Exercises.- 3.3 Microprocessor Design Case Study.- 3.3.1 Ground Model DLXseq.- 3.3.2 Parallel Model DLXpar Resolving Structural Hazards.- 3.3.3 Verifying Resolution of Structural Hazards (DLXpar).- 3.3.4 Resolving Data Hazards (Refinement DLXdata).- 3.3.5 Exercises.- 4 Structured ASMs (Composition Techniques).- 4.1 Turbo ASMs (seq, iterate, submachines, recursion).- 4.1.1 Seq and Iterate (Structured Programming).- 4.1.2 Submachines and Recursion (Encapsulation and Hiding).- 4.1.3 Analysis of Turbo ASM Steps.- 4.1.4 Exercises.- 4.2 Abstract State Processes (Interleaving).- 5 Synchronous Multi-Agent ASMs.- 5.1 Robot Controller Case Study.- 5.1.1 Production Cell Ground Model.- 5.1.2 Refinement of the Production Cell Component ASMs.- 5.1.3 Exercises.- 5.2 Real-Time Controller (Railroad Crossing Case Study).- 5.2.1 Real-TimeProcess Control Systems.- 5.2.2 Railroad Crossing Case Study.- 5.2.3 Exercises.- 6 Asynchronous Multi-Agent ASMs.- 6.1 Async ASMs: Definition and Network Examples.- 6.1.1 Mutual Exclusion.- 6.1.2 Master-Slave Agreement.- 6.1.3 Network Consensus.- 6.1.4 Load Balance.- 6.1.5 Leader Election and Shortest Path.- 6.1.6 Broadcast Acknowledgment (Echo).- 6.1.7 Phase Synchronization.- 6.1.8 Routing Layer Protocol for Mobile Ad Hoc Networks.- 6.1.9 Exercises.- 6.2 Embedded System Case Study.- 6.2.1 Light Control Ground Model.- 6.2.2 Signature (Agents and Their State).- 6.2.3 User Interaction (Manual Control).- 6.2.4 Automatic Control.- 6.2.5 Failure and Service.- 6.2.6 Component Structure.- 6.2.7 Exercises.- 6.3 Time-Constrained Async ASMs.- 6.3.1 Kermit Case Study (Alternating Bit/Sliding Window).- 6.3.2 Processor-Group-Membership Protocol Case Study.- 6.3.3 Exercises.- 6.4 Async ASMs with Durative Actions.- 6.4.1 Protocol Verification using Atomic Actions.- 6.4.2 Refining Atomic to Durative Actions.- 6.4.3 Exercises.- 6.5 Event-Driven ASMs.- 6.5.1 UML Diagrams for Dynamics.- 6.5.2 Exercises.- 7 Universal Design and Computation Model.- 7.1 Integrating Computation and Specification Models.- 7.1.1 Classical Computation Models.- 7.1.2 System Design Models.- 7.1.3 Exercises.- 7.2 Sequential ASM Thesis (A Proof from Postulates).- 7.2.1 Gurevich's Postulates for Sequential Algorithms.- 7.2.2 Bounded-Choice Non-Determinism.- 7.2.3 Critical Terms for ASMs.- 7.2.4 Exercises.- 8 Tool Support for ASMs.- 8.1 Verification of ASMs.- 8.1.1 Logic for ASMs.- 8.1.2 Formalizing the Consistency of ASMs.- 8.1.3 Basic Axioms and Proof Rules of the Logic.- 8.1.4 Why Deterministic Transition Rules?.- 8.1.5 Completeness for Hierarchical ASMs.- 8.1.6 The Henkin Model Construction.- 8.1.7 An Extension with Explicit Step Information.- 8.1.8 Exercises.- 8.2 Model Checking of ASMs.- 8.3 Execution of ASMs.- 9 History and Survey of ASM Research.- 9.1 The Idea of Sharpening Turing's Thesis.- 9.2 Recognizing the Practical Relevance of ASMs.- 9.3 Testing the Practicability of ASMs.- 9.3.1 Architecture Design and Virtual Machines.- 9.3.2 Protocols.- 9.3.3 Why use ASMs for Hw/Sw Engineering?.- 9.4 Making ASMs Fit for their Industrial Deployment.- 9.4.1 Practical Case Studies.- 9.4.2 Industrial Pilot Projects and Further Applications.- 9.4.3 Tool Integration.- 9.5 Conclusion and Outlook.- References.- List of Problems.- List of Figures.- List of Tables.
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abstract state machines a method for high level system design and analysis
2003Co-Authors: Egon Borger, Robert F StarkAbstract:1 Introduction.- 1.1 Goals of the Book and Contours of its Method.- 1.1.1 Stepwise Refinable Abstract Operational Modeling.- 1.1.2 Abstract Virtual Machine Notation.- 1.1.3 Practical Benefits.- 1.1.4 Harness Pseudo-Code by Abstraction and Refinement.- 1.1.5 Adding Abstraction and Rigor to UML Models.- 1.2 Synopsis of the Book.- 2 ASM Design and Analysis Method.- 2.1 Principles of Hierarchical System Design.- 2.1.1 Ground Model Construction (Requirements Capture).- 2.1.2 Stepwise Refinement (Incremental Design).- 2.1.3 Integration into Software Practice.- 2.2 Working Definition.- 2.2.1 Basic ASMs.- 2.2.2 Definition.- 2.2.3 Classification of Locations and Updates.- 2.2.4 ASM Modules.- 2.2.5 Illustration by Small Examples.- 2.2.6 Control State ASMs.- 2.2.7 Exercises.- 2.3 Explanation by Example: Correct Lift Control.- 2.3.1 Exercises.- 2.4 Detailed Definition (Math. Foundation).- 2.4.1 Abstract States and Update Sets.- 2.4.2 Mathematical Logic.- 2.4.3 Transition Rules and Runs of ASMs.- 2.4.4 The Reserve of ASMs.- 2.4.5 Exercises.- 2.5 Notational Conventions.- 3 Basic ASMs.- 3.1 Requirements Capture by Ground Models.- 3.1.1 Fundamental Questions to be Asked.- 3.1.2 Illustration by Small Use Case Models.- 3.1.3 Exercises.- 3.2 Incremental Design by Refinements.- 3.2.1 Refinement Scheme and its Specializations.- 3.2.2 Two Refinement Verification Case Studies.- 3.2.3 Decomposing Refinement Verifications.- 3.2.4 Exercises.- 3.3 Microprocessor Design Case Study.- 3.3.1 Ground Model DLXseq.- 3.3.2 Parallel Model DLXpar Resolving Structural Hazards.- 3.3.3 Verifying Resolution of Structural Hazards (DLXpar).- 3.3.4 Resolving Data Hazards (Refinement DLXdata).- 3.3.5 Exercises.- 4 Structured ASMs (Composition Techniques).- 4.1 Turbo ASMs (seq, iterate, submachines, recursion).- 4.1.1 Seq and Iterate (Structured Programming).- 4.1.2 Submachines and Recursion (Encapsulation and Hiding).- 4.1.3 Analysis of Turbo ASM Steps.- 4.1.4 Exercises.- 4.2 Abstract State Processes (Interleaving).- 5 Synchronous Multi-Agent ASMs.- 5.1 Robot Controller Case Study.- 5.1.1 Production Cell Ground Model.- 5.1.2 Refinement of the Production Cell Component ASMs.- 5.1.3 Exercises.- 5.2 Real-Time Controller (Railroad Crossing Case Study).- 5.2.1 Real-TimeProcess Control Systems.- 5.2.2 Railroad Crossing Case Study.- 5.2.3 Exercises.- 6 Asynchronous Multi-Agent ASMs.- 6.1 Async ASMs: Definition and Network Examples.- 6.1.1 Mutual Exclusion.- 6.1.2 Master-Slave Agreement.- 6.1.3 Network Consensus.- 6.1.4 Load Balance.- 6.1.5 Leader Election and Shortest Path.- 6.1.6 Broadcast Acknowledgment (Echo).- 6.1.7 Phase Synchronization.- 6.1.8 Routing Layer Protocol for Mobile Ad Hoc Networks.- 6.1.9 Exercises.- 6.2 Embedded System Case Study.- 6.2.1 Light Control Ground Model.- 6.2.2 Signature (Agents and Their State).- 6.2.3 User Interaction (Manual Control).- 6.2.4 Automatic Control.- 6.2.5 Failure and Service.- 6.2.6 Component Structure.- 6.2.7 Exercises.- 6.3 Time-Constrained Async ASMs.- 6.3.1 Kermit Case Study (Alternating Bit/Sliding Window).- 6.3.2 Processor-Group-Membership Protocol Case Study.- 6.3.3 Exercises.- 6.4 Async ASMs with Durative Actions.- 6.4.1 Protocol Verification using Atomic Actions.- 6.4.2 Refining Atomic to Durative Actions.- 6.4.3 Exercises.- 6.5 Event-Driven ASMs.- 6.5.1 UML Diagrams for Dynamics.- 6.5.2 Exercises.- 7 Universal Design and Computation Model.- 7.1 Integrating Computation and Specification Models.- 7.1.1 Classical Computation Models.- 7.1.2 System Design Models.- 7.1.3 Exercises.- 7.2 Sequential ASM Thesis (A Proof from Postulates).- 7.2.1 Gurevich's Postulates for Sequential Algorithms.- 7.2.2 Bounded-Choice Non-Determinism.- 7.2.3 Critical Terms for ASMs.- 7.2.4 Exercises.- 8 Tool Support for ASMs.- 8.1 Verification of ASMs.- 8.1.1 Logic for ASMs.- 8.1.2 Formalizing the Consistency of ASMs.- 8.1.3 Basic Axioms and Proof Rules of the Logic.- 8.1.4 Why Deterministic Transition Rules?.- 8.1.5 Completeness for Hierarchical ASMs.- 8.1.6 The Henkin Model Construction.- 8.1.7 An Extension with Explicit Step Information.- 8.1.8 Exercises.- 8.2 Model Checking of ASMs.- 8.3 Execution of ASMs.- 9 History and Survey of ASM Research.- 9.1 The Idea of Sharpening Turing's Thesis.- 9.2 Recognizing the Practical Relevance of ASMs.- 9.3 Testing the Practicability of ASMs.- 9.3.1 Architecture Design and Virtual Machines.- 9.3.2 Protocols.- 9.3.3 Why use ASMs for Hw/Sw Engineering?.- 9.4 Making ASMs Fit for their Industrial Deployment.- 9.4.1 Practical Case Studies.- 9.4.2 Industrial Pilot Projects and Further Applications.- 9.4.3 Tool Integration.- 9.5 Conclusion and Outlook.- References.- List of Problems.- List of Figures.- List of Tables.
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the asm Ground Model method as a foundation of requirements engineering
Lecture Notes in Computer Science, 2003Co-Authors: Egon BorgerAbstract:Building Ground Models is one of the three constituents of the engineering method for computer-based systems which is known as Abstract State Machine (ASM) method [16]. In this note we characterize Ground Models, whose epistemological role for a foundation of system design resembles the one Aristotle assigned to axioms to Ground science in reality, avoiding infinite regress. We explain how ASM Ground Models help to resolve two major problems of requirements engineering, providing means a) to obtain for complex computer-based systems an adequate understanding by humans, and b) to cope with ever-changing requirements by faithfully capturing and tracing them via well-documented Modeling-for-change. We point out that via an appropriate refinement method one can relate Ground Models to executable code.1
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high level system design and analysis using abstract state machines
Lecture Notes in Computer Science, 1999Co-Authors: Egon BorgerAbstract:We provide an introduction to a practical method for rigorous system development which has been used successfully, under industrial constraints, for design and analysis of complex hardware/software systems. The method allows one to start system development with a trustworthy high level system specification and to link such a Ground Model in a well documented and inspectable way through intermediate design steps to its implementation. The method enhances traditional operational Modelling and analysis techniques by incorporating the most, general abstraction, decomposition and refinement mechanisms which have become available through Gurevich's Abstract State Machines. Through its versatility the ASM approach is non-monolithic and integratable at any development level into current design and analysis environments. We also collect experimental evidence for the ASM thesis, a generalization of Turing's thesis.
Sarah M Springman - One of the best experts on this subject based on the ideXlab platform.
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application of geotechnical and geophysical field measurements in an active alpine environment
Engineering Geology, 2017Co-Authors: Daisy Lucas, Kerstin Fankhauser, Sarah M SpringmanAbstract:Abstract A gravelly scree slope in the Meretschibach catchment, a location in the Swiss Alps in the vicinity of Agarn, canton Valais, has been observed to deform downslope at up to 0.5 m p.a. The potential instabilities at this site include surficial landslides, some of them originally thought to be triggered by an increase in pore water pressure with a subsequent loss of shear strength as a consequence of rainfall infiltration and rockfalls. A programme consisting of monitoring, laboratory testing and investigation was developed, to perform a thorough soil characterisation needed in order to produce a realistic Ground Model. The long-term geotechnical monitoring included in situ soil temperature, suction as well as volumetric water content measurements using dielectric permittivity and time domain reflectometry (TDR) sensors. This data was complemented by electrical resistivity tomography (ERT) to provide extensive knowledge on the depth to bedrock and to validate the volumetric water contents in specific locations. The datasets are completed by recordings from two nearby weather stations. Seasonal changes of precipitation and temperature were reflected in corresponding trends in all measurements. A comparison of volumetric water content records was obtained using capacitance and time domain reflectometry (TDR) sensors with ERT, yielding reasonable agreement. The resulting Ground Model, which integrates all currently available parameters, delivers the essential information and boundary conditions for predicting and validating slope instabilities in the future, using numerical and physical Modelling.
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amendments to interpretations of saaf inclinometer data from the furggwanghorn rock glacier turtmann valley switzerland results from 2010 to 2012
Vadose Zone Journal, 2016Co-Authors: Thomas Buchli, Jan Laue, Sarah M SpringmanAbstract:Raw data processing from a ShapeAccelArray field (SAAF) inclinometer were made using proprietary software from Measurand, the manufacturer of the SAAF inclinometer. When the inclinometer data obtained from the same borehole were reprocessed with an updated software version, the results were found to differ significantly from the values derived using the previous version of software. Neither the absolute displacements, nor the curve representing displacements with depth, agreed with the previous values, despite best attempts to compare data with alternative sparse field measurements of surface displacements. There was a change in inclination of the segments above the shear zone, and the strain rates in the shear zone were reduced significantly during the winter months. In contrast, there was no change in the depth of the shear zone. Therefore, the Ground Model presented in the original study is still considered to be the optimal Ground Model of the Furggwanghorn rock glacier. Finally, a simple trigonometrical approach was conducted to investigate the validity of both software versions. The simplified recalculations could confirm mostly the results of the updated software version.
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application of geotechnical and geophysical field measurements in an active alpine environment
IOP Conference Series: Earth and Environmental Science, 2015Co-Authors: Daisy Lucas, Kerstin Fankhauser, Sarah M SpringmanAbstract:Rainfall can trigger landslides, rockfalls and debris flow events. When rainfall infiltrates into the soil, the suction (if there is any) is reduced, until positive water pressure can be developed, decreasing the effective stresses and leading to a potential failure. A challenging site for the study of mass movement is the Meretschibach catchment, a location in the Swiss Alps in the vicinity of Agarn, Canton of Valais. To study the effect of rainfall on slope stabilities, the soil characterization provides valuable insight on soil properties, necessary to establish a realistic Ground Model. This Model, together with an effective long term-field monitoring, deliver the essential information and boundary conditions for predicting and validating rainfall- induced slope instabilities using numerical and physical Modelling. Geotechnical monitoring, including soil temperature and volumetric water content measurements, has been performed on the study site together with geophysical measurements (ERT) to study the effect of rainfall on the (potential) triggering of landslides on a scree slope composed of a surficial layer of gravelly soil. These techniques were combined to provide information on the soil characteristics and depth to the bedrock. Seasonal changes of precipitation and temperature were reflected in corresponding trends in all measurements. A comparison of volumetric water content records was obtained from decagons, time domain reflectometry (TDR) and electrical resistivity tomography (ERT) conducted throughout the spring and summer months of 2014, yielding a reasonable agreement.
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volumetric water content determination by tdr sensors and decagons in gravelly soils
XVI European Conference on Soil Mechanics and Geotechnical Engineering (XVI ECSMGE 2015), 2015Co-Authors: Daisy Lucas, Amin Askarinejad, Ralf Herzog, Ernst Bleiker, Sarah M SpringmanAbstract:Rainfall can trigger landslides, rockfalls and debris flow events. When rainfall infiltrates into the soil, the suction (if there is any) is reduced, until positive water pressure can be developed, decreasing the effective stresses and leading to a potential failure. A challenging site for the study of mass movement is the Meretschibach catchment, a location in the Swiss Alps in the vicinity of Agarn, Canton of Valais. To study the effect of rainfall on slope stabilities, the soil characterization provides valuable insight on soil properties, necessary to establish a realistic Ground Model. This Model, together with an effective long term-field monitoring, deliver the essential information and boundary conditions for predicting and validating rainfall- induced slope instabilities using numerical and physical Modelling. Geotechnical monitoring, including soil temperature and volumetric water content measurements, has been performed on the study site together with geophysical measurements (ERT) to study the effect of rainfall on the (potential) triggering of landslides on a scree slope composed of a surficial layer of gravelly soil. These techniques were combined to provide information on the soil characteristics and depth to the bedrock. Seasonal changes of precipitation and temperature were reflected in corresponding trends in all measurements. A comparison of volumetric water content records was obtained from decagons, time domain reflectometry (TDR) and electrical resistivity tomography (ERT) conducted throughout the spring and summer months of 2014, yielding a reasonable agreement.
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characterization and monitoring of the furggwanghorn rock glacier turtmann valley switzerland results from 2010 to 2012
Vadose Zone Journal, 2013Co-Authors: Thomas Buchli, Kaspar Merz, Xiaohai Zhou, Wolfgang Kinzelbach, Sarah M SpringmanAbstract:Climate effects relating to air temperature, radiation, snow cover, and rainfall combine with thaw and infiltration processes to cause changes in the thermal response and associated creep deformations in rock glaciers, which are the geomorphological expression of Alpine permafrost. The annual surface creep of some rock glaciers has accelerated recently by an order of magnitude. A multidisciplinary field study links characterization, monitoring, and Modeling for such a rock glacier in the Turtmann valley in Switzerland. The first phase consisted of characterization using seismic refraction and Ground-penetrating radar (GPR), as well as borehole information and monitoring of meteorological, hydrothermal, and geotechnical variables over 2 yr. The Ground Model confirmed the heterogeneity of the internal structure, with rock glacier topography affecting the thermal distribution in boreholes and seepage flows from tracer tests at between 10 and 40 m h−1. Temperatures were generally warmer than −0.25°C in the permafrost zone, with some variability in terms of thermal degradation of some layers to 0°C and an active layer of about 3 to 5 m depth. Unique internal shear movements were measured by an automatic inclinometer, which indicated downslope creep rates in the shear zone and at the surface of about 2.4 and 3.2 m yr−1 respectively, which could not be directly linked to temperature at the same depth. These rock glaciers have potential for future instability, which could damage infrastructure in the valley below. It is essential to understand why they have accelerated over the past decade through the complex interactions that have controlled the thermo-hydromechanical response.
Hiroshi Sakai - One of the best experts on this subject based on the ideXlab platform.
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The weakly compact reflection principle need not imply a high order of weak compactness
Archive for Mathematical Logic, 2019Co-Authors: Brent Cody, Hiroshi SakaiAbstract:The weakly compact reflection principle\({\mathrm{Refl}}_{{\mathrm{wc}}}(\kappa )\) states that \(\kappa \) is a weakly compact cardinal and every weakly compact subset of \(\kappa \) has a weakly compact proper initial segment. The weakly compact reflection principle at \(\kappa \) implies that \(\kappa \) is an \(\omega \)-weakly compact cardinal. In this article we show that the weakly compact reflection principle does not imply that \(\kappa \) is \((\omega +1)\)-weakly compact. Moreover, we show that if the weakly compact reflection principle holds at \(\kappa \) then there is a forcing extension preserving this in which \(\kappa \) is the least \(\omega \)-weakly compact cardinal. Along the way we generalize the well-known result which states that if \(\kappa \) is a regular cardinal then in any forcing extension by \(\kappa \)-c.c. forcing the nonstationary ideal equals the ideal generated by the Ground Model nonstationary ideal; our generalization states that if \(\kappa \) is a weakly compact cardinal then after forcing with a ‘typical’ Easton-support iteration of length \(\kappa \) the weakly compact ideal equals the ideal generated by the Ground Model weakly compact ideal.
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on the set generic multiverse
arXiv: Logic, 2018Co-Authors: Sydavid Friedman, Sakae Fuchino, Hiroshi SakaiAbstract:The forcing method is a powerful tool to prove the consistency of set-theoretic assertions relative to the consistency of the axioms of set theory. Laver’s theorem and Bukovský’s theorem assert that set-generic extensions of a given Ground Model constitute a quite reasonable and sufficiently general class of standard Models of set-theory.
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the weakly compact reflection principle need not imply a high order of weak compactness
arXiv e-prints, 2017Co-Authors: Brent Cody, Hiroshi SakaiAbstract:The weakly compact reflection principle $\text{Refl}_{\text{wc}}(\kappa)$ states that $\kappa$ is a weakly compact cardinal and every weakly compact subset of $\kappa$ has a weakly compact proper initial segment. The weakly compact reflection principle at $\kappa$ implies that $\kappa$ is an $\omega$-weakly compact cardinal. In this article we show that the weakly compact reflection principle does not imply that $\kappa$ is $(\omega+1)$-weakly compact. Moreover, we show that if the weakly compact reflection principle holds at $\kappa$ then there is a forcing extension preserving this in which $\kappa$ is the least $\omega$-weakly compact cardinal. Along the way we generalize the well-known result which states that if $\kappa$ is a regular cardinal then in any forcing extension by $\kappa$-c.c. forcing the nonstationary ideal equals the ideal generated by the Ground Model nonstationary ideal; our generalization states that if $\kappa$ is a weakly compact cardinal then after forcing with a `typical' Easton-support iteration of length $\kappa$ the weakly compact ideal equals the ideal generated by the Ground Model weakly compact ideal.
Klausdieter Schewe - One of the best experts on this subject based on the ideXlab platform.
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towards a workflow engine by stepwise refinement
2014Co-Authors: Felix Kossak, Christa Illibauer, Verena Geist, Jan Kubovy, Christine Natschlager, Thomas Ziebermayr, Theodorich Kopetzky, Bernhard Freudenthaler, Klausdieter ScheweAbstract:In this chapter we propose an approach for stepwise refinement of the rigorous semantics for Business Process Model and Notation (BPMN) Process Diagrams presented in Chap. 4. The suggested approach hence fills the gap between an Abstract State Machine (ASM) Ground Model and a common workflow engine, such as Red Hat JBoss [109], Activiti [5], Bonita Execution Engine [16], Route [77] or Enhydra Shark [135]. We base the refinement approach on the definition of a specific notification concept. This concept implements the event flow by allowing notifications to be passed through a context tree in a similar way as tokens are passed through sequence flows. This also enables communication with a process from the outside world by putting notifications on the top of the context tree.
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using abstract state machines for distributed data warehouse design
Asia-Pacific Conference on Conceptual Modelling, 2004Co-Authors: Jane Zaho, Klausdieter ScheweAbstract:Data Warehouses are data-intensive systems that are used for analytical tasks. As these tasks do not depend on the latest updates by transactions, data warehouses can be set up in a way that input of data from operational databases and output to dialogue interfaces for on-line analytical processes (OLAP) can be separated. In the paper we describe how abstract state machines (ASMs) can be used to design distributed data warehouses. We formalise the Ground idea of data warehouses by a Ground Model ASM and discuss refinement steps, which can be applied in a step-by-step design methodology. Distribution will appear as such a refinement step.
Brent Cody - One of the best experts on this subject based on the ideXlab platform.
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The weakly compact reflection principle need not imply a high order of weak compactness
Archive for Mathematical Logic, 2019Co-Authors: Brent Cody, Hiroshi SakaiAbstract:The weakly compact reflection principle\({\mathrm{Refl}}_{{\mathrm{wc}}}(\kappa )\) states that \(\kappa \) is a weakly compact cardinal and every weakly compact subset of \(\kappa \) has a weakly compact proper initial segment. The weakly compact reflection principle at \(\kappa \) implies that \(\kappa \) is an \(\omega \)-weakly compact cardinal. In this article we show that the weakly compact reflection principle does not imply that \(\kappa \) is \((\omega +1)\)-weakly compact. Moreover, we show that if the weakly compact reflection principle holds at \(\kappa \) then there is a forcing extension preserving this in which \(\kappa \) is the least \(\omega \)-weakly compact cardinal. Along the way we generalize the well-known result which states that if \(\kappa \) is a regular cardinal then in any forcing extension by \(\kappa \)-c.c. forcing the nonstationary ideal equals the ideal generated by the Ground Model nonstationary ideal; our generalization states that if \(\kappa \) is a weakly compact cardinal then after forcing with a ‘typical’ Easton-support iteration of length \(\kappa \) the weakly compact ideal equals the ideal generated by the Ground Model weakly compact ideal.
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the weakly compact reflection principle need not imply a high order of weak compactness
arXiv e-prints, 2017Co-Authors: Brent Cody, Hiroshi SakaiAbstract:The weakly compact reflection principle $\text{Refl}_{\text{wc}}(\kappa)$ states that $\kappa$ is a weakly compact cardinal and every weakly compact subset of $\kappa$ has a weakly compact proper initial segment. The weakly compact reflection principle at $\kappa$ implies that $\kappa$ is an $\omega$-weakly compact cardinal. In this article we show that the weakly compact reflection principle does not imply that $\kappa$ is $(\omega+1)$-weakly compact. Moreover, we show that if the weakly compact reflection principle holds at $\kappa$ then there is a forcing extension preserving this in which $\kappa$ is the least $\omega$-weakly compact cardinal. Along the way we generalize the well-known result which states that if $\kappa$ is a regular cardinal then in any forcing extension by $\kappa$-c.c. forcing the nonstationary ideal equals the ideal generated by the Ground Model nonstationary ideal; our generalization states that if $\kappa$ is a weakly compact cardinal then after forcing with a `typical' Easton-support iteration of length $\kappa$ the weakly compact ideal equals the ideal generated by the Ground Model weakly compact ideal.
