Pme Pieter Van Gorp

Lifelong Personal Health Data and Application Software via Virtual Machines in the Cloud

Personal Health Records (PHRs) should remain the lifelong property of patients, who should be able to show them conveniently and securely to selected caregivers and institutions. In this paper, we present MyPHRMachines, a cloud-based PHR system taking a radically new architectural solution to health record portability. In MyPHRMachines, health-related data and the application software to view and/or analyze it are separately deployed in the PHR system. After uploading their medical data to MyPHRMachines, patients can access them again from remote virtual machines that contain the right software to visualize and analyze them without any need for conversion. Patients can share their remote virtual machine session with selected caregivers, who will need only a Web browser to access the pre-loaded fragments of their lifelong PHR. We discuss a prototype of MyPHRMachines applied to two use cases, i.e., radiology image sharing and personalized medicine.

A visual token-based formalization of BPMN 2.0 based on in-place transformations

Context: The Business Process Model and Notation (BPMN) standard informally defines a precise execution semantics. It defines how process instances should be updated in a model during execution. Existing formalizations of the standard are incomplete and rely on mappings to other languages. Objective: This paper provides a BPMN 2.0 semantics formalization that is more complete and intuitive than existing formalizations. Method: The formalization consists of in-place graph transformation rules that are documented visually using BPMN syntax. In-place transformations update models directly and do not require mappings to other languages. We have used a mature tool and test-suite to develop a reference implementation of all rules. Results: Our formalization is a promising complement to the standard, in particular because all rules have been extensively verified and because conceptual validation is facilitated (the informal semantics also describes in-place updates). Conclusion: Since our formalization has already revealed problems with the standard and since the BPMN is still evolving, the maintainers of the standard can benefit from our results. Moreover, tool vendors can use our formalization and reference implementation for verifying conformance to the standard.

Supporting the internet-based evaluation of research software with cloud infrastructure

Due to license restrictions and installation issues, it is often not feasible to experiment with software without making substantial investments. Especially in the case of legacy tools, it turns out that even free software is often too costly (i.e., time-consuming) to be installed for evaluating the quality of a research contribution. After organizing a series of events related to software modeling, we have constructed (and started to use) SHARE, a system for sharing practically any type of software artifact to reviewers and to other participants who have very limited time available. The system relies on cloud-computing technologies to provide online access to interactive environments containing all the tools, documentation, input and output models to reproduce alleged research results. The system also enables one to clone such an environment and add additional models or tools in order to extend a contribution or pinpoint a problem. In retrospect, we observe that the approach is not limited to software modeling and SHARE is in fact gaining acceptance in other fields already.

BPMN 2.0 execution semantics formalized as graph rewrite rules

The Business Process Model and Notation (BPMN) standard version 2.0 informally denes a precise execution semantics. This paper denes that execution semantics formally, by dening the execution rules as graph rewrite rules. The paper shows that the formal denition of execution rules in this manner is intuitive and simple, in particular because they can be specied graphically, using the BPMN symbols, while maintaining mathematical rigour. Using graph rewriting tools, the resulting formal execution semantics can be used to directly execute models that are created in the BPMN. Therefore, it can be used as a reference implementation of the execution semantics and to test BPMN 2.0 engines, in combination with a set of BPMN test models that we also provide.

Synthesizing object life cycles from business process models

Unified modeling language (UML) activity diagrams can model the flow of stateful business objects among activities, implicitly specifying the life cycles of those objects. The actual object life cycles are typically expressed in UML state machines. The implicit life cycles in UML activity diagrams need to be discovered in order to derive the actual object life cycles or to check the consistency with an existing life cycle. This paper presents an automated approach for synthesizing a UML state machine modeling the life cycle of an object that occurs in different states in a UML activity diagram. The generated state machines can contain parallelism, loops, and cross-synchronization. The approach makes life cycles that have been modeled implicitly in activity diagrams explicit. The synthesis approach has been implemented using a graph transformation tool and has been applied in several case studies.

MyPHRMachines: Lifelong Personal Health Records in the cloud

Personal Health Records (PHRs) should remain the lifelong property of patients and should be showable conveniently and securely to selected caregivers. Regarding interoperability, current solutions for PHRsfocus on standard data exchange formats and transformations to move data across health information systems. In this paper we propose MyPHRMachines, a patient-centric system that takes a radically new architectural solution to health record interoperability. We propose to deploy besides the medical data also the related software to the PHR system. After uploading their medical data to MyPHRMachines, patients can access them again from remote virtual machines that contain the right software to visualize and analyze them without any conversion. Patients can share their remote virtual machine session with a selected health provider, who will need only a Web browser to access the pre-loaded fragments of the lifelong PHR. We illustrate how our prototype already supports the use case of a real-world patient and discuss the research agenda required to translate this prototype into a viable solution for the international healthcare industry.

Transforming process models: executable rewrite rules versus a formalized java program

In the business process management community, transformations for process models are usually programmed using imperative languages (such as Java). The underlying mapping rules tend to be documented using informal visual rules whereas they tend to be formalized using mathematical set constructs. In the Graph and Model Transformation communities, special purpose languages and tools (such as GrGen) are being developed to support the direct execution of such mapping rules. As part of our ongoing effort to bridge these two communities, we have implemented a transformation from petri-nets to statecharts (PN2SC) using both approaches. By relying on technical comparison criteria and by making the solutions available for online replay, we illustrate that rule-based approaches require less specification effort due to their more declarative specification style and automatic performance optimizations. From a tool perspective, GrGen has better visualization and debugging support whereas Java tools support evolution better.

Synthesizing data-centric models from business process models

Data-centric business process models couple data and control flow to specify flexible business processes. However, it can be difficult to predict the actual behavior of a data-centric model, since the global process is typically distributed over several data elements and possibly specified in a declarative way. We therefore envision a data-centric process modeling approach in which the default behavior of the process is first specified in a classical, imperative process notation, which is then transformed to a declarative, data-centric process model that can be further refined into a complete model. To support this vision, we define a semi-automated approach to synthesize an object-centric design from a business process model that specifies the flow of multiple stateful objects between activities. The object-centric design specifies in an imperative way the life cycles of the objects and the object interactions. Next, we define a mapping from an object-centric design to a declarative Guard-Stage-Milestone schema, which can be refined into a complete specification of a data-centric BPM system. The synthesis approach has been implemented and tested using a graph transformation tool.

Addressing health information privacy with a novel cloud-based PHR system architecture

Patient Health Records (PHRs) shift the ownership of health data from health providers to patients. Such a shift poses important challenges from the data privacy point of view. Patients would like to be able to selectively reveal information to other stakeholders and, at the same time, be assured that their health information will not be used improperly once shared. Current PHR systems partially fail to satisfy these requirements. In this paper, we show that both requirements can be satisfied fully when adopting a novel cloud-based PHR system architecture.We expain the role of remote virtual machines in this architecture and use interaction models to reason about privacy implications. Finally, we evaluate MyPHRMachines, a prototypical implementation of the architecture: we demonstrate that the system enables the execution of third party genome analysis services on patientowned genome data while ensuring that (1) such services cannot maliciously store this data and (2) patients can show the analysis results to experts without sharing along their full genome.

Analyzing conformance to clinical protocols involving advanced synchronizations

Clinical protocols are a popular instrument to document how clinicians are expected to behave under specific conditions. Protocols are typically based on internationally peer reviewed clinical guidelines as well as on hospital-local agreements. Existing techniques for monitoring protocol adherence only support protocol descriptions involving simple sequences and local decision rules. As care and cure processes are becoming increasingly complex, the need for more advanced techniques naturally emerges. In this paper we present a novel approach to defining and monitoring complex clinical protocols. By using BPMN to document protocols we enable the concise specification of protocols that involve multiple stakeholders that operate in parallel and under uncertainty. Uncertainty relates to the fact that protocols may involve complex loops and choices. While this specification style was becoming increasingly popular in the literature and practice of hospital management and operations management in general, corresponding conformance analysis techniques were still lacking. This paper contributes the first such technique and evaluate it on a complex compliance pattern from the cardiology domain.