Event Stream Processing with Multiple Threads

Current runtime verification tools seldom make use of multi-threading to speed up the evaluation of a property on a large event trace. In this paper, we present an extension to the BeepBeep 3 event stream engine that allows the use of multiple threads during the evaluation of a query. Various parallelization strategies are presented and described on simple examples. The implementation of these strategies is then evaluated empirically on a sample of problems. Compared to the previous, single-threaded version of the BeepBeep engine, the allocation of just a few threads to specific portions of a query provides dramatic improvement in terms of running time

Quality of Service Behavioral Model from Event Trace Analysis

Proc. of the 7th international Command and Control Research and Technology Symposium (CCRTS 2002), Quebec City, Canada, pp. 1-16.The distributed command & control environment includes limited computer resources and numerous mission critical applications competing for these scarce resources. Additionally the stringent constraints and considerable complexity of distributed command & control systems can create a condition that places extreme demands upon the allocated resources and invites a potential for program errors. Consistent quality of service distribution can be a critical element in ensuring effective overall program completion while avoiding potential errors and process failures. The potential for errors and process failures can be understood and addressed by performing a practical analysis of the resource deployment procedures utilized within this environment. However, analyzing resource-based quality of service within a distributed command & control environment is a demanding endeavor. This difficult task can be simplified by directly examining specific quality of service actions that take place during program execution. Therefore, topragmatically isolate these actions and develop a practical quality of service behavioral model, the research discussed in this paper has implemented an event trace approach to examine the exact quality of service execution path during program operation

A new model for designing uncertain enterprise architecture

C4ISR framework describes architecture in three views of information architecture and defines a set of products, which are main outputs of enterprise architecture design. Formats and templates, which are presented for C4ISR products, cannot describe uncertainty in process or data. Meanwhile, uncertainty in many information systems is unavoidable and using the concept of fuzzy numbers in architecture design helps architects handle uncertainty in process and data of organization. In this paper, we present a new template based on fuzzy-UML concept for some of C4ISR products such as Logical Data Model (OV-7), Operational Event/Trace Description (OV-6c) and Systems Event/Trace Description (SV-10c). To explain further, fictional Fast Pass system used at OilCo gas stations is used to demonstrate details of our proposed model

Hierarchical architecture design and simulation environment

The Hierarchical Architectural design and Simulation Environment (HASE)is intended as a flexible tool for computer architects who wish to experiment with alternative architectural configurations and design parameters. HASE is both a design environment and a simulator. Architecture components are described by a hierarchical library of objects defined in terms of an object oriented simulation language. HASE instantiates these objects to simulate and animate the execution of a computer architecture. An event trace generated by the simulator therefore describes the interaction between architecture components, for example, fetch stages, address and data buses, sequencers, instruction buffers and register files. The objects can model physical components at different abstraction levels, eg. PMS (processor memory switch), ISP (instruction set processor) and RTL (register transfer level). HASE applies the concepts of inheritance, encapsulation and polymorphism associated with object orientation, to simplify the design and implementation of an architecture simulation that models component operations at different abstraction levels. For example, HASE can probe the performance of a processor's floating point unit, executing a multiplication operation, at a lower level of abstraction, i.e. the RTL, whilst simulating remaining architecture components at a PMS level of abstraction. By adopting this approach, HASE returns a more meaningful and relevant event trace from an architecture simulation. Furthermore, an animator visualises the simulation's event trace to clarify the collaborations and interactions between architecture components. The prototype version of HASE is based on GSS (Graphical Support System), and DEMOS (Discrete Event Modelling On Simula)

Prognosing the Compliance of Declarative Business Processes Using Event Trace Robustness

Several proposals have studied the compliance of execution of business process traces in accordance with a set of compliance rules. Unfortunately, the detection of a compliance violation (diagnosis) means that the observed events have already violated the compliance rules that describe the model. In turn, the detection of a compliance violation before its actual occurrence would prevent misbehaviour of the business processes. This functionality is referred to as proactive management of compliance violations in literature. However, existing approaches focus on the detection of inconsistencies between the compliance rules or monitoring process instances that are in a violable state. The notion of robustness could help us to prognosticate the occurrence of these inconsistent states in a premature way, and to detect, depending on the current execution state of the process instance, how “close” the execution is to a possible violation. On top of being able to possibly avoid violations, a robust trace is not sensitive to small changes. In this paper we propose the way to determine whether a process instance is robust against a set of compliance rules during its execution at runtime. Thanks to the use of constraint programming and the capacities of super solutions, a robust trace can be guaranteed

Efficient Large-scale Trace Checking Using MapReduce

The problem of checking a logged event trace against a temporal logic specification arises in many practical cases. Unfortunately, known algorithms for an expressive logic like MTL (Metric Temporal Logic) do not scale with respect to two crucial dimensions: the length of the trace and the size of the time interval for which logged events must be buffered to check satisfaction of the specification. The former issue can be addressed by distributed and parallel trace checking algorithms that can take advantage of modern cloud computing and programming frameworks like MapReduce. Still, the latter issue remains open with current state-of-the-art approaches. In this paper we address this memory scalability issue by proposing a new semantics for MTL, called lazy semantics. This semantics can evaluate temporal formulae and boolean combinations of temporal-only formulae at any arbitrary time instant. We prove that lazy semantics is more expressive than standard point-based semantics and that it can be used as a basis for a correct parametric decomposition of any MTL formula into an equivalent one with smaller, bounded time intervals. We use lazy semantics to extend our previous distributed trace checking algorithm for MTL. We evaluate the proposed algorithm in terms of memory scalability and time/memory tradeoffs.Comment: 13 pages, 8 figure

An Event Structure Model for Probabilistic Concurrent Kleene Algebra

We give a new true-concurrent model for probabilistic concurrent Kleene algebra. The model is based on probabilistic event structures, which combines ideas from Katoen's work on probabilistic concurrency and Varacca's probabilistic prime event structures. The event structures are compared with a true-concurrent version of Segala's probabilistic simulation. Finally, the algebraic properties of the model are summarised to the extent that they can be used to derive techniques such as probabilistic rely/guarantee inference rules.Comment: Submitted and accepted for LPAR19 (2013

A Monitoring Language for Run Time and Post-Mortem Behavior Analysis and Visualization

UFO is a new implementation of FORMAN, a declarative monitoring language, in which rules are compiled into execution monitors that run on a virtual machine supported by the Alamo monitor architecture.Comment: In M. Ronsse, K. De Bosschere (eds), proceedings of the Fifth International Workshop on Automated Debugging (AADEBUG 2003), September 2003, Ghent. cs.SE/030902