Amjad Gawanmeh

A verification methodology for a wireless body sensor network functionality

Modern healthcare systems benefit from the phenomenal advances that continue to be made in ICT. These advances have resulted in the development of several technologies that have become fundamental parts of electronic healthcare systems such as wireless body sensor networks (WBSNs). WBSNs integrate wearable and implanted devices with wireless communication and information processing systems to monitor the well-being of an individual. Testing and verification of WBSNs are of paramount importance as faults in these critical systems may lead to loss of life. In this paper, we propose a framework to verify the functionality of WBSN healthcare system using formal methods. We adopted a practical WBSN design, and provided a model for its behavior, then defined several properties for its correct operation, and finally we used theorem proving method to show that the proposed design correctly implements the required properties.

Reliability analysis of healthcare information systems: State of the art and future directions

Testing and verification of healthcare information systems is a challenging and important issue since faults in these critical systems may lead to loss of lives, and in the best cases, loss of money and reputations. However, due to the complexity of these systems, and the increasing demand for new products and new technologies in this domain, there are several methods and technologies being used for testing these systems. In this paper, we review the state of the art on testing and verification of healthcare information systems, and then we identify several open issues and challenges in the area. We divide the exiting methods into three categories: simulation based methods, formal methods, and other techniques such as semi-formal methods. Then, we discuss challenging and open issues in the domain.

Formalizing electrocardiogram (ECG) signal behavior in event-B

Recording the electrical activity of the heart over a period of time as detected using electrical sensors is referred to as Electrocardiography (ECG). ECG is recorded as a collection of signal waves that has repetitive patterns. These patterns are usually used in the complex diagnosis process through which ECG may indicate certain problems related to the heart or other parts of the body. Despite the extensive studies conducted on the analysis of ECG signals and their thorough analysis, there is a lack of a formal model that validate their specifications, which results in several inconsistencies and problems in their interpretations and usage. This, on the other hand, may lead to ambiguities and incompleteness in the methods that are developed utilizing ECG specifications and their features. Therefore, in this paper we propose a method to formalize and validate the specifications of ECG signals in Event-B. We formally define the waves of ECG and their relation, and then formalize and validate several properties about their behavior.

Assertion based verification of PSL for SystemC designs

In this paper, we present an assertion based verification approach for SystemC designs, based on embedding the property specification language (PSL) using abstract state machines (ASM). Our approach utilizes an existing embedding of PSL in ASM in order to enable modeling of PSL assertions at the ASM level. Here, we propose to compile PSL assertions into C# code, and integrate them with the SystemC design. Assertions are then verified by simulating the new model that combines the original design and the integrated assertions. This enriches the SystemC language with a powerful and expressive assertion specification layer, and improves the verification of SystemC designs by targeting specific properties during simulation.

An axiomatic model for formal specification requirements of ubiquitous healthcare systems

Formal models are necessary to capture the semantics and behavior of processes of various systems. They characterize and provide insight into the behavior of real systems and thus identify their deterministic and non-deterministic features. The design and deployment of healthcare systems utilize the current technology development in order to improve healthcare services and accommodate the increasing demand on these services while maintaining high quality and error free service. However, healthcare systems lack a formal model that can precisely define specification requirements about their design and operation. This paper introduces a formal axiomatic model for ubiquitous healthcare systems. This formal model precisely defines the formal specification requirements for healthcare systems including functional and security related requirements.

Formal validation of QRS wave within ECG

Electrical sensors are used to detect and record the electrical activity of the heart over a period of time, this operation is referred to as Electrocardiography (ECG) in medical science. Hence ECG is composed of a set of signal waves that repeats themselves and are usually useful in medical diagnosis, where certain ECG patterns and the occupancy of specific waves, such as the QRS wave, may indicate certain heart problems. In this paper, we extend our previous results where we provided a high level model for ECG wave, with a more concrete model for QRS waves at several levels of abstraction in order to validate the specification of the QRS waves and several properties related to its behavior. We use formal method since medical applications still suffer from design and understanding problems when implemented in ICT context despite the use of thorough test through simulation techniques which may lead to ambiguities and incompleteness in the developed methods for using ECG specifications in medical diagnosis. We used the Event-B formal method to successfully formalize the QRS wave in the ECG of the heart system at several levels of abstraction, and then defined and validated several properties that are related to its wavelet shape and behavior.

Formal reliability analysis of a typical FHIR standard based e-Health system using PRISM

Fast Health Interoperable Resources (FHIR) is the recently proposed standard from HL7. Its distinguishing features include the user friendly implementation, support of built-in terminologies and for widely-used web standards. Given the safety-critical nature of FHIR, the rigorous analysis of e-health systems using the FHIR is a dire need since they are prone to failures. As a first step towards this direction, we propose to use probabilistic model checking, i.e., a formal probabilistic analysis approach, to assess the reliability of a typical e-health system used in hospitals based on the FHIR standard. In particular, we use the PRISM model checker to analyze the Markov Decision Process (MDP) and Continuous Time Markov Chain (CTMC) models to assess the failure probabilities of the overall system.

Interfacing ASM with the MDG tool

In this paper we describe an approach to interface Abstract State Machines (ASM) with Multiway Decision Graphs (MDG) to enable tool support for the formal verification of ASM descriptions. ASM is a specification method for software and hardware providing a powerful means of modeling various kinds of systems. MDGs are decision diagrams based on abstract representation of data and are used primarily for modeling hardware systems. The notions of ASM and MDG are hence closely related to each other, making it appealing to link these two concepts. The proposed interface between ASM and MDG uses two steps: first, the ASM model is transformed into a flat, simple transition system as an intermediate model. Second, this intermediate model is transformed into the syntax of the input language of the MDG tool, MDG-HDL. We have successfully applied this transformation scheme on a case study, the Island Tunnel Controller, where we automatically generated the corresponding MDG-HDL models from ASM specifications.

Formal verification of ASM designs using the MDG tool

In this paper, we present a formal hardware verification framework linking ASM with MDG. ASM (Abstract State Machine) is a state based language for describing transition systems. MDG (Multiway Decision Graphs) provides symbolic representation of transition systems with support of abstract sorts and functions. We implemented a transformation tool that automatically generates MDG models from ASM specifications, then formal verification techniques provided by the MDG tool, such as model checking or equivalence checking, can be applied on the generated models. We support this work with a case study of an Island Tunnel Controller, which behavior and structure were specified in ASM then using our ASM-MDG tool successfully verified within the MDG tool.

Embedding and Verification of PSL using ASM

This paper proposes a methodology to integrate the property specification language (PSL) in the verification process of systems designed using abstract states machines (ASMs). A specification of PSL in ASM was provided, which allows us to integrate PSL properties as part of the design. For the verification, a technique based on the AsmL tool was proposed that translates the ASM code (containing both the design and the properties) into a finite state machine (FSM) representation. The generated FSM was used to run model checking on an external tool, here SMV. The approach takes advantage from the ASM language capabilities to model designs at the system level as well as from the power of the AsmL tool in generating both a C# code and an FSM representation from an ASM model. The approach was applied on SystemC designs, which are translated into ASM models. Experimental results on a bus structure from the SystemC library showed a superiority of the approach to conventional verification