The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform
Rahul Mangharam - One of the best experts on this subject based on the ideXlab platform.
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Closed-loop verification of medical devices with model abstraction and refinement
International Journal on Software Tools for Technology Transfer, 2014Co-Authors: Zhihao Jiang, Miroslav Pajic, Rajeev Alur, Rahul MangharamAbstract:The design and implementation of software for medical devices is challenging due to the closed-loop interaction with the patient, which is a stochastic physical environment. The safety-critical nature and the lack of existing industry standards for verification make this an ideal domain for exploring applications of formal modeling and closed-loop analysis. The biggest challenge is that the environment model(s) have to be both complex enough to express the physiological requirements and general enough to cover all possible inputs to the device. In this effort, we use a dual chamber implantable Pacemaker as a case study to demonstrate verification of software specifications of medical devices as timed-automata models in UPPAAL. The Pacemaker model is based on the specifications and algorithm descriptions from Boston Scientific. The heart is modeled using timed automata based on the physiology of heart. The model is gradually abstracted with timed simulation to preserve properties. A manual Counter-Example-Guided Abstraction and Refinement (CEGAR) framework has been adapted to refine the heart model when spurious counter-examples are found. To demonstrate the closed-loop nature of the problem and heart model refinement, we investigated two clinical cases of Pacemaker Mediated Tachycardia and verified their corresponding correction algorithms in the Pacemaker. Along with our tools for code generation from UPPAAL models, this effort enables model-driven design and certification of software for medical devices.
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modeling and verification of a dual chamber implantable Pacemaker
Tools and Algorithms for Construction and Analysis of Systems, 2012Co-Authors: Zhihao Jiang, Miroslav Pajic, Salar Moarref, Rajeev Alur, Rahul MangharamAbstract:The design and implementation of software for medical devices is challenging due to their rapidly increasing functionality and the tight coupling of computation, control, and communication. The safety-critical nature and the lack of existing industry standards for verification, make this an ideal domain for exploring applications of formal modeling and analysis. In this study, we use a dual chamber implantable Pacemaker as a case study for modeling and verification of control algorithms for medical devices in UPPAAL. We begin with detailed models of the Pacemaker, based on the specifications and algorithm descriptions from Boston Scientific. We then define the state space of the closed-loop system based on its heart rate and developed a heart model which can non-deterministically cover the whole state space. For verification, we first specify unsafe regions within the state space and verify the closed-loop system against corresponding safety requirements. As stronger assertions are attempted, the closed-loop unsafe state may result from healthy open-loop heart conditions. Such unsafe transitions are investigated with two clinical cases of Pacemaker Mediated Tachycardia and their corresponding correction algorithms in the Pacemaker. Along with emerging tools for code generation from UPPAAL models, this effort enables model-driven design and certification of software for medical devices.
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Modeling and Verification of a Dual Chamber Implantable Pacemaker. TACAS
2012Co-Authors: Zhihao Jiang, Miroslav Pajic, Salar Moarref, Rajeev Alur, Rahul MangharamAbstract:Abstract. The design and implementation of software for medical devices is challenging due to their rapidly increasing functionality and the tight coupling of computation, control, and communication. The safetycritical nature and the lack of existing industry standards for verification, make this an ideal domain for exploring applications of formal modeling and analysis. In this study, we use a dual chamber implantable Pacemaker as a case study for modeling and verification of control algorithms for medical devices in UPPAAL. We begin with detailed models of the Pacemaker, based on the specifications and algorithm descriptions from Boston Scientific. We then define the state space of the closed-loop system based on its heart rate and developed a heart model which can nondeterministically cover the whole state space. For verification, we first specify unsafe regions within the state space and verify the closed-loop system against corresponding safety requirements. As stronger assertions are attempted, the closed-loop unsafe state may result from healthy openloop heart conditions. Such unsafe transitions are investigated with two clinical cases of Pacemaker Mediated Tachycardia and their corresponding correction algorithms in the Pacemaker. Along with emerging tools for code generation from UPPAAL models, this effort enables modeldriven design and certification of software for medical devices
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Model-Based Closed-Loop Testing of Implantable Pacemakers
2011 IEEE/ACM Second International Conference on Cyber-Physical Systems, 2011Co-Authors: Zhihao Jiang, Miroslav Pajic, Rahul MangharamAbstract:The increasing complexity of software in implantable medical devices such as cardiac Pacemakers and defibrillators accounts for over 40% of device recalls. Testing remains the principal means of verification in the medical device certification regime. Traditional software test generation techniques, where the tests are generated independently of the operational environment, are not effective as the device must be tested within the context of the patient's condition and the current state of the heart. It is necessary for the testing system to observe the system state and conditionally generate the next input to advance the purpose of the test. To this effect, a set of general and patient condition-specific temporal requirements is specified for the closed-loop heart and Pacemaker system. Based on these requirements, we describe a closed-loop testing environment between a timed automata-based heart model and a Pacemaker. This allows for interactive and physiologically relevant model-based test generation for basic Pacemaker device operations such as maintaining the heart rate and a trial-ventricle synchrony. We also demonstrate the flexibility and efficacy of the testing environment for more complex common timing anomalies such as reentry circuits, Pacemaker mode switch operation and Pacemaker-Mediated Tachycardia. This system is a step toward a testing approach for medical cyber-physical systems with the patient-in-the-loop.
Zhihao Jiang - One of the best experts on this subject based on the ideXlab platform.
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Closed-loop verification of medical devices with model abstraction and refinement
International Journal on Software Tools for Technology Transfer, 2014Co-Authors: Zhihao Jiang, Miroslav Pajic, Rajeev Alur, Rahul MangharamAbstract:The design and implementation of software for medical devices is challenging due to the closed-loop interaction with the patient, which is a stochastic physical environment. The safety-critical nature and the lack of existing industry standards for verification make this an ideal domain for exploring applications of formal modeling and closed-loop analysis. The biggest challenge is that the environment model(s) have to be both complex enough to express the physiological requirements and general enough to cover all possible inputs to the device. In this effort, we use a dual chamber implantable Pacemaker as a case study to demonstrate verification of software specifications of medical devices as timed-automata models in UPPAAL. The Pacemaker model is based on the specifications and algorithm descriptions from Boston Scientific. The heart is modeled using timed automata based on the physiology of heart. The model is gradually abstracted with timed simulation to preserve properties. A manual Counter-Example-Guided Abstraction and Refinement (CEGAR) framework has been adapted to refine the heart model when spurious counter-examples are found. To demonstrate the closed-loop nature of the problem and heart model refinement, we investigated two clinical cases of Pacemaker Mediated Tachycardia and verified their corresponding correction algorithms in the Pacemaker. Along with our tools for code generation from UPPAAL models, this effort enables model-driven design and certification of software for medical devices.
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modeling and verification of a dual chamber implantable Pacemaker
Tools and Algorithms for Construction and Analysis of Systems, 2012Co-Authors: Zhihao Jiang, Miroslav Pajic, Salar Moarref, Rajeev Alur, Rahul MangharamAbstract:The design and implementation of software for medical devices is challenging due to their rapidly increasing functionality and the tight coupling of computation, control, and communication. The safety-critical nature and the lack of existing industry standards for verification, make this an ideal domain for exploring applications of formal modeling and analysis. In this study, we use a dual chamber implantable Pacemaker as a case study for modeling and verification of control algorithms for medical devices in UPPAAL. We begin with detailed models of the Pacemaker, based on the specifications and algorithm descriptions from Boston Scientific. We then define the state space of the closed-loop system based on its heart rate and developed a heart model which can non-deterministically cover the whole state space. For verification, we first specify unsafe regions within the state space and verify the closed-loop system against corresponding safety requirements. As stronger assertions are attempted, the closed-loop unsafe state may result from healthy open-loop heart conditions. Such unsafe transitions are investigated with two clinical cases of Pacemaker Mediated Tachycardia and their corresponding correction algorithms in the Pacemaker. Along with emerging tools for code generation from UPPAAL models, this effort enables model-driven design and certification of software for medical devices.
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Modeling and Verification of a Dual Chamber Implantable Pacemaker. TACAS
2012Co-Authors: Zhihao Jiang, Miroslav Pajic, Salar Moarref, Rajeev Alur, Rahul MangharamAbstract:Abstract. The design and implementation of software for medical devices is challenging due to their rapidly increasing functionality and the tight coupling of computation, control, and communication. The safetycritical nature and the lack of existing industry standards for verification, make this an ideal domain for exploring applications of formal modeling and analysis. In this study, we use a dual chamber implantable Pacemaker as a case study for modeling and verification of control algorithms for medical devices in UPPAAL. We begin with detailed models of the Pacemaker, based on the specifications and algorithm descriptions from Boston Scientific. We then define the state space of the closed-loop system based on its heart rate and developed a heart model which can nondeterministically cover the whole state space. For verification, we first specify unsafe regions within the state space and verify the closed-loop system against corresponding safety requirements. As stronger assertions are attempted, the closed-loop unsafe state may result from healthy openloop heart conditions. Such unsafe transitions are investigated with two clinical cases of Pacemaker Mediated Tachycardia and their corresponding correction algorithms in the Pacemaker. Along with emerging tools for code generation from UPPAAL models, this effort enables modeldriven design and certification of software for medical devices
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Model-Based Closed-Loop Testing of Implantable Pacemakers
2011 IEEE/ACM Second International Conference on Cyber-Physical Systems, 2011Co-Authors: Zhihao Jiang, Miroslav Pajic, Rahul MangharamAbstract:The increasing complexity of software in implantable medical devices such as cardiac Pacemakers and defibrillators accounts for over 40% of device recalls. Testing remains the principal means of verification in the medical device certification regime. Traditional software test generation techniques, where the tests are generated independently of the operational environment, are not effective as the device must be tested within the context of the patient's condition and the current state of the heart. It is necessary for the testing system to observe the system state and conditionally generate the next input to advance the purpose of the test. To this effect, a set of general and patient condition-specific temporal requirements is specified for the closed-loop heart and Pacemaker system. Based on these requirements, we describe a closed-loop testing environment between a timed automata-based heart model and a Pacemaker. This allows for interactive and physiologically relevant model-based test generation for basic Pacemaker device operations such as maintaining the heart rate and a trial-ventricle synchrony. We also demonstrate the flexibility and efficacy of the testing environment for more complex common timing anomalies such as reentry circuits, Pacemaker mode switch operation and Pacemaker-Mediated Tachycardia. This system is a step toward a testing approach for medical cyber-physical systems with the patient-in-the-loop.
Miroslav Pajic - One of the best experts on this subject based on the ideXlab platform.
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Closed-loop verification of medical devices with model abstraction and refinement
International Journal on Software Tools for Technology Transfer, 2014Co-Authors: Zhihao Jiang, Miroslav Pajic, Rajeev Alur, Rahul MangharamAbstract:The design and implementation of software for medical devices is challenging due to the closed-loop interaction with the patient, which is a stochastic physical environment. The safety-critical nature and the lack of existing industry standards for verification make this an ideal domain for exploring applications of formal modeling and closed-loop analysis. The biggest challenge is that the environment model(s) have to be both complex enough to express the physiological requirements and general enough to cover all possible inputs to the device. In this effort, we use a dual chamber implantable Pacemaker as a case study to demonstrate verification of software specifications of medical devices as timed-automata models in UPPAAL. The Pacemaker model is based on the specifications and algorithm descriptions from Boston Scientific. The heart is modeled using timed automata based on the physiology of heart. The model is gradually abstracted with timed simulation to preserve properties. A manual Counter-Example-Guided Abstraction and Refinement (CEGAR) framework has been adapted to refine the heart model when spurious counter-examples are found. To demonstrate the closed-loop nature of the problem and heart model refinement, we investigated two clinical cases of Pacemaker Mediated Tachycardia and verified their corresponding correction algorithms in the Pacemaker. Along with our tools for code generation from UPPAAL models, this effort enables model-driven design and certification of software for medical devices.
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modeling and verification of a dual chamber implantable Pacemaker
Tools and Algorithms for Construction and Analysis of Systems, 2012Co-Authors: Zhihao Jiang, Miroslav Pajic, Salar Moarref, Rajeev Alur, Rahul MangharamAbstract:The design and implementation of software for medical devices is challenging due to their rapidly increasing functionality and the tight coupling of computation, control, and communication. The safety-critical nature and the lack of existing industry standards for verification, make this an ideal domain for exploring applications of formal modeling and analysis. In this study, we use a dual chamber implantable Pacemaker as a case study for modeling and verification of control algorithms for medical devices in UPPAAL. We begin with detailed models of the Pacemaker, based on the specifications and algorithm descriptions from Boston Scientific. We then define the state space of the closed-loop system based on its heart rate and developed a heart model which can non-deterministically cover the whole state space. For verification, we first specify unsafe regions within the state space and verify the closed-loop system against corresponding safety requirements. As stronger assertions are attempted, the closed-loop unsafe state may result from healthy open-loop heart conditions. Such unsafe transitions are investigated with two clinical cases of Pacemaker Mediated Tachycardia and their corresponding correction algorithms in the Pacemaker. Along with emerging tools for code generation from UPPAAL models, this effort enables model-driven design and certification of software for medical devices.
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Modeling and Verification of a Dual Chamber Implantable Pacemaker. TACAS
2012Co-Authors: Zhihao Jiang, Miroslav Pajic, Salar Moarref, Rajeev Alur, Rahul MangharamAbstract:Abstract. The design and implementation of software for medical devices is challenging due to their rapidly increasing functionality and the tight coupling of computation, control, and communication. The safetycritical nature and the lack of existing industry standards for verification, make this an ideal domain for exploring applications of formal modeling and analysis. In this study, we use a dual chamber implantable Pacemaker as a case study for modeling and verification of control algorithms for medical devices in UPPAAL. We begin with detailed models of the Pacemaker, based on the specifications and algorithm descriptions from Boston Scientific. We then define the state space of the closed-loop system based on its heart rate and developed a heart model which can nondeterministically cover the whole state space. For verification, we first specify unsafe regions within the state space and verify the closed-loop system against corresponding safety requirements. As stronger assertions are attempted, the closed-loop unsafe state may result from healthy openloop heart conditions. Such unsafe transitions are investigated with two clinical cases of Pacemaker Mediated Tachycardia and their corresponding correction algorithms in the Pacemaker. Along with emerging tools for code generation from UPPAAL models, this effort enables modeldriven design and certification of software for medical devices
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Model-Based Closed-Loop Testing of Implantable Pacemakers
2011 IEEE/ACM Second International Conference on Cyber-Physical Systems, 2011Co-Authors: Zhihao Jiang, Miroslav Pajic, Rahul MangharamAbstract:The increasing complexity of software in implantable medical devices such as cardiac Pacemakers and defibrillators accounts for over 40% of device recalls. Testing remains the principal means of verification in the medical device certification regime. Traditional software test generation techniques, where the tests are generated independently of the operational environment, are not effective as the device must be tested within the context of the patient's condition and the current state of the heart. It is necessary for the testing system to observe the system state and conditionally generate the next input to advance the purpose of the test. To this effect, a set of general and patient condition-specific temporal requirements is specified for the closed-loop heart and Pacemaker system. Based on these requirements, we describe a closed-loop testing environment between a timed automata-based heart model and a Pacemaker. This allows for interactive and physiologically relevant model-based test generation for basic Pacemaker device operations such as maintaining the heart rate and a trial-ventricle synchrony. We also demonstrate the flexibility and efficacy of the testing environment for more complex common timing anomalies such as reentry circuits, Pacemaker mode switch operation and Pacemaker-Mediated Tachycardia. This system is a step toward a testing approach for medical cyber-physical systems with the patient-in-the-loop.
Bruce B. Lerman - One of the best experts on this subject based on the ideXlab platform.
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Validation of device algorithm to differentiate Pacemaker-Mediated Tachycardia from Tachycardia due to atrial tracking
Heart rhythm, 2016Co-Authors: Bruce B. LermanAbstract:Background Current cardiac devices cannot always differentiate between Pacemaker-Mediated Tachycardia (PMT) and tracking of sinus or atrial Tachycardia. We previously derived a novel algorithm for distinguishing the 2 mechanisms based on the specific termination response to postventricular atrial refractory period extension, atrial rates, and changes in atrial electrogram morphology. Objective The purpose of this study was to evaluate how this algorithm would have performed in a clinical setting based on previously recorded PMT events. Methods We applied our algorithm to a database of 122 de-identified stored electrograms that were classified as PMT by 43 remotely monitored devices. Results Of the 122 events stored as "PMT," 3 episodes were excluded because the device recording was consistent with atrial fibrillation. Of the remaining 119 episodes, our algorithm was able to correctly reclassify 92 events (77%) as tracking of sinus or atrial Tachycardia rather than true PMT. The VAV response following postventricular atrial refractory period extension, which is specific to tracking of atrial or sinus Tachycardia, was seen in 72% of these cases. Changes in atrial rate and atrial electrogram morphology were able to reclassify the remainder of episodes. Finally, we observed that 12 of 83 episodes (14%) misclassified as PMT in cardiac resynchronization devices resulted in loss of cardiac biventricular pacing. Conclusion Applying a novel diagnostic algorithm to current cardiac devices improves the proper diagnosis of true PMT rather than tracking of atrial or sinus Tachycardia. Enhanced accuracy of diagnosis reduces the likelihood of inappropriate clinical decisions.
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Differentiating Pacemaker-Mediated Tachycardia from Tachycardia due to atrial tracking: Utility of V-A-A-V versus V-A-V response after postventricular atrial refractory period extension
Heart rhythm, 2011Co-Authors: Steven M. Markowitz, Christopher F. Liu, Jim W. Cheung, George Thomas, Bruce B. LermanAbstract:Background Dual-chamber Pacemaker systems can lead to two forms of Pacemaker-facilitated Tachycardia: Pacemaker-Mediated Tachycardia (PMT) and tracking of sinus or atrial Tachycardia. Current Pacemaker algorithms cannot always differentiate between these two Tachycardias. Objective The purpose of this study was to investigate a novel algorithm for distinguishing the two mechanisms of Pacemaker-facilitated Tachycardia, which is based on the specific termination response to postventricular atrial refractory period (PVARP) extension. Methods We prospectively tested our algorithm using the Medtronic Virtual Interactive patient (VIP) II simulator (version 1.53) and a Medtronic Adapta ADDR01 dual-chamber Pacemaker. Results Thirty-five scenarios that triggered "PMT detection" by the device were evaluated. All 12 scenarios of atrial Tachycardias with intact AV conduction terminated with a Vp-Ar-Vs (V-A-V) response as a result of PVARP extension. Of the 11 scenarios of atrial Tachycardia with complete heart block, all terminated with a Vp-Ar-As-Vp response. All four episodes of PMT with intact AV conduction terminated with a Vp-Ar-As-Vs (V-A-A-Vs) response. Of the eight episodes of PMT with complete heart block, all terminated with a Vp-Ar-As-Vp response. Conclusion In the presence of intact AV conduction, the V-A-V response to PVARP extension is specific to atrial (or sinus) Tachycardia, whereas the V-A-A-Vs response is specific to PMT. Recognizing the difference between the two forms of Pacemaker-facilitated Tachycardias has important implications for Pacemaker programming.
Rajeev Alur - One of the best experts on this subject based on the ideXlab platform.
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Closed-loop verification of medical devices with model abstraction and refinement
International Journal on Software Tools for Technology Transfer, 2014Co-Authors: Zhihao Jiang, Miroslav Pajic, Rajeev Alur, Rahul MangharamAbstract:The design and implementation of software for medical devices is challenging due to the closed-loop interaction with the patient, which is a stochastic physical environment. The safety-critical nature and the lack of existing industry standards for verification make this an ideal domain for exploring applications of formal modeling and closed-loop analysis. The biggest challenge is that the environment model(s) have to be both complex enough to express the physiological requirements and general enough to cover all possible inputs to the device. In this effort, we use a dual chamber implantable Pacemaker as a case study to demonstrate verification of software specifications of medical devices as timed-automata models in UPPAAL. The Pacemaker model is based on the specifications and algorithm descriptions from Boston Scientific. The heart is modeled using timed automata based on the physiology of heart. The model is gradually abstracted with timed simulation to preserve properties. A manual Counter-Example-Guided Abstraction and Refinement (CEGAR) framework has been adapted to refine the heart model when spurious counter-examples are found. To demonstrate the closed-loop nature of the problem and heart model refinement, we investigated two clinical cases of Pacemaker Mediated Tachycardia and verified their corresponding correction algorithms in the Pacemaker. Along with our tools for code generation from UPPAAL models, this effort enables model-driven design and certification of software for medical devices.
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modeling and verification of a dual chamber implantable Pacemaker
Tools and Algorithms for Construction and Analysis of Systems, 2012Co-Authors: Zhihao Jiang, Miroslav Pajic, Salar Moarref, Rajeev Alur, Rahul MangharamAbstract:The design and implementation of software for medical devices is challenging due to their rapidly increasing functionality and the tight coupling of computation, control, and communication. The safety-critical nature and the lack of existing industry standards for verification, make this an ideal domain for exploring applications of formal modeling and analysis. In this study, we use a dual chamber implantable Pacemaker as a case study for modeling and verification of control algorithms for medical devices in UPPAAL. We begin with detailed models of the Pacemaker, based on the specifications and algorithm descriptions from Boston Scientific. We then define the state space of the closed-loop system based on its heart rate and developed a heart model which can non-deterministically cover the whole state space. For verification, we first specify unsafe regions within the state space and verify the closed-loop system against corresponding safety requirements. As stronger assertions are attempted, the closed-loop unsafe state may result from healthy open-loop heart conditions. Such unsafe transitions are investigated with two clinical cases of Pacemaker Mediated Tachycardia and their corresponding correction algorithms in the Pacemaker. Along with emerging tools for code generation from UPPAAL models, this effort enables model-driven design and certification of software for medical devices.
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Modeling and Verification of a Dual Chamber Implantable Pacemaker. TACAS
2012Co-Authors: Zhihao Jiang, Miroslav Pajic, Salar Moarref, Rajeev Alur, Rahul MangharamAbstract:Abstract. The design and implementation of software for medical devices is challenging due to their rapidly increasing functionality and the tight coupling of computation, control, and communication. The safetycritical nature and the lack of existing industry standards for verification, make this an ideal domain for exploring applications of formal modeling and analysis. In this study, we use a dual chamber implantable Pacemaker as a case study for modeling and verification of control algorithms for medical devices in UPPAAL. We begin with detailed models of the Pacemaker, based on the specifications and algorithm descriptions from Boston Scientific. We then define the state space of the closed-loop system based on its heart rate and developed a heart model which can nondeterministically cover the whole state space. For verification, we first specify unsafe regions within the state space and verify the closed-loop system against corresponding safety requirements. As stronger assertions are attempted, the closed-loop unsafe state may result from healthy openloop heart conditions. Such unsafe transitions are investigated with two clinical cases of Pacemaker Mediated Tachycardia and their corresponding correction algorithms in the Pacemaker. Along with emerging tools for code generation from UPPAAL models, this effort enables modeldriven design and certification of software for medical devices
