Formal Modelling of Complex Event Processing and its Application to a Manufacturing Line

Identifying the significant and most needed information in huge enterprises at the right time not only helps in decision making, but also plays an important role in overall performance and profit making of enterprises. Complex Event Processing (CEP) is a developing method of processing different events from multiple sources and filtering them to produce complex events. This thesis provides a methodology to model CEP using Timed Net Condition Event System (TNCES), a Petri Nets derived formalism. Petri Nets is a graphical, mathematical modelling language used to analyze and describe discrete-event dynamic systems. The biggest advantage of representing CEP in TNCES is that it opens paths to the validation of the events filtering and decision making in different level of enterprise. /Kir1

Automatic Generation of C from Event-B

Abstract. Event-B [15] is a formal modeling method intended to support refinement, an initial system description at a high level of abstraction with detail added in successive understandable steps. The refinement process may be carried to its logical conclusion, specification of all detail needed to define an executable in a high-level language, and automatic generation of source code from the model via a suitable tool. The introduction of the RODIN [20] tool-set allows such extensions to be provided by third-party developers [3], and translation of Event-B to the C [12] programming language has always been intended [2]. This paper discusses the requirements of such a tool, introduces the B2C extension to RODIN that has been developed to meet these needs, and describes its use on a practical example. 1

Efficient hardware for low latency applications

The design and development of application specific hardware structures has a high degree of complexity. Logic resources are nowadays often not the limit anymore, but the development time. The first part presents a generator which allows defining control and status structures for hardware designs using an abstract high level language. A novel method to inform host systems very efficiently about changes in the register files is presented in the second part. It makes use of a microcode programmable hardware unit. In the third part a fully pipelined address translation mechanism for remote memory access in HPC interconnection networks is presented, which features a new concept to resolve dependency problems. The last part of this thesis addresses the problem of sending TCP messages for a low latency trading application using a hybrid TCP stack implementation that consists of hardware and software components. Furthermore, a simulation environment for the TCP stack is presented

A Design Framework for Reactive and Time-triggered Embedded Systems via the UML-SystemC bridge

Ph.DDOCTOR OF PHILOSOPH

Scheduling of guarded command based models

Formal methods provide a means of reasoning about computer programs in order to prove correctness criteria. One subtype of formal methods is based on the weakest precondition predicate transformer semantics and uses guarded commands as the basic modelling construct. Examples of such formalisms are Action Systems and Event-B. Guarded commands can intuitively be understood as actions that may be triggered when an associated guard condition holds. Guarded commands whose guards hold are nondeterministically chosen for execution, but no further control flow is present by default. Such a modelling approach is convenient for proving correctness, and the Refinement Calculus allows for a stepwise development method. It also has a parallel interpretation facilitating development of concurrent software, and it is suitable for describing event-driven scenarios. However, for many application areas, the execution paradigm traditionally used comprises more explicit control flow, which constitutes an obstacle for using the above mentioned formal methods. In this thesis, we study how guarded command based modelling approaches can be conveniently and efficiently scheduled in different scenarios. We first focus on the modelling of trust for transactions in a social networking setting. Due to the event-based nature of the scenario, the use of guarded commands turns out to be relatively straightforward. We continue by studying modelling of concurrent software, with particular focus on compute-intensive scenarios. We go from theoretical considerations to the feasibility of implementation by evaluating the performance and scalability of executing a case study model in parallel using automatic scheduling performed by a dedicated scheduler. Finally, we propose a more explicit and non-centralised approach in which the flow of each task is controlled by a schedule of its own. The schedules are expressed in a dedicated scheduling language, and patterns assist the developer in proving correctness of the scheduled model with respect to the original one

Designing Data-Driven Virtual Patients for Health Sciences Education

Electronic virtual patients (VPs) are interactive screen-based computer simulations of real-life clinical scenarios that are widely used for the purposes of health sciences education. Advances in computational modeling and availability of large patient cohort datasets from Electronic Medical Record (EMR) systems have created an opportunity to develop a new type of VPs, where cases are based on and simulate real patient clinical treatment processes and outcomes. Traditional VP cases are static narrative representations of clinical scenarios that are presented to health sciences students in order to teach a clinical topic of interest. This research investigates the feasibility of authoring and presenting virtual patient cases that leverage Bayesian network (BN) models learned from EMR data to present clinical scenarios and control outcomes of learners' decisions within the context of a presented VP. Because the underlying models are based on real patient data, each decision made by a learner would affect the probability of each outcome occurring in the same way as with real patients. Additionally, this dissertation explores the challenges related to using BN models in the context of VP case authoring and presentation, and experimentally compares a VP case based on a BN model to one created using a traditional narrative-branched VP system across multiple categories, including meeting learning objectives, accuracy in depicting the chosen clinical scenario, introducing/reinforcing relevant clinical skills, providing formative feedback, scenario realism, and learner engagement. Furthermore, this work investigates the extent to which the use of annotated BN models in VP cases facilitates modifying an existing VP case by allowing case authors to manipulate the underlying model in such a way that the modified VP case meets alternate learning objectives. Last, but not least, this research provides practical and methodological contributions to the body of work in the areas of health sciences education, problem-based learning, and clinical simulation design and evaluation. More specifically, this work (1) defines criteria and guidelines for designing VP cases based on BN models, (2) identifies and describes shortcomings and challenges associated with different BN modeling approaches for different types of clinical scenarios, (3) and presents a framework for evaluating VP cases