Other Computer Engineering Commons^™

Cyber-Physical Modeling Of Implantable Cardiac Medical Devices, Zhihao Jiang, Miroslav Pajic, Rahul Mangharam

Rahul Mangharam

The design of bug-free and safe medical device software is challenging, especially in complex implantable devices that control and actuate organs in unanticipated contexts. Safety recalls of pacemakers and implantable cardioverter defibrillators between 1990 and 2000 affected over 600,000 devices. Of these, 200,000 or 41%, were due to firmware issues and their effect continues to increase in frequency. There is currently no formal methodology or open experimental platform to test and verify the correct operation of medical device software within the closed-loop context of the patient. To this effect, a real-time Virtual Heart Model (VHM) has been developed to model …

From Verification To Implementation: A Model Translation Tool And A Pacemaker Case Study, Miroslav Pajic, Zhihao Jiang, Insup Lee, Oleg Sokolsky, Rahul Mangharam

Rahul Mangharam

Model-Driven Design (MDD) of cyber-physical systems advocates for design procedures that start with formal modeling of the real-time system, followed by the model’s verification at an early stage. The verified model must then be translated to a more detailed model for simulation-based testing and finally translated into executable code in a physical implementation. As later stages build on the same core model, it is essential that models used earlier in the pipeline are valid approximations of the more detailed models developed downstream. The focus of this effort is on the design and development of a model translation tool, UPP2SF, and …

Modeling Cardiac Pacemaker Malfunctions With The Virtual Heart Model, Zhihao Jiang, Rahul Mangharam

Rahul Mangharam

Implantable cardiac devices such as artificial pacemakers deliver therapies according to the timing information from the heart. Such devices work under the assumptions of perfect sensing, which are: (a) the pacemaker leads remain in place, and (b) the pacing therapy in one chamber (e.g. atrium) is insulated from the other chambers (e.g. ventricles). But there are common cases which violate these assumptions and the mechanisms for imperfect sensing cannot be captured by a simple signal generator. In this paper we use the Penn Virtual Heart Model (VHM) to investigate the spatial and temporal aspects of the electrical conduction system of …

Model-Based Closed-Loop Testing Of Implantable Pacemakers, Zhihao Jiang, Miroslav Pajic, Rahul Mangharam

Rahul Mangharam

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 …

Contextualized Mobile Support For Learning By Doing In The Real World, Ray Bareiss, Natalie Linnell, Martin L. Griss

Martin L Griss

This research addresses the use of mobile devices with both embedded and external sensors to provide contextualized help, advice, and remediation to learners engaged in real-world learn-by-doing tasks. This work is situated within the context of learning a complex procedure, in particular emergency responders learning to conduct urban search and rescue operations. Research issues include the design and delivery of contextualized performance support and the inferring of learner actions and intentions from sensor data to ensure that the right support is delivered just in time, as it is relevant to what the learner is doing.

A Critical Perfomance Analysis Of Thin Client Platforms, Faith J. Shimba, Renatus Michael

Faith Joel Shimba

The nature of operation of Thin Client computing makes their performance to be affected by both the quality of the network and the terminals. For the past few years, there are few analyses on the performance of Thin Clients that can produce reliable, valid, and up-to-date results collected in a well designed and evaluated experiment based research. This paper analyses the performance of Thin Clients through experiment based research. The approach is to use benchmark application which is designed specifically for measurement of desktop computers by inserting delays in the visual elements of such benchmark application. In this technique, packet’s …

Solving Problems Of Virus Definition Files - A Triz Perspective, Umakant Mishra

Umakant Mishra

Signature scanning is the most popular method of virus scanning and is adopted by all anti-virus programs. Signature scanning is capable of detecting more than 80% of viruses. It uses a simple logic and uses less memory and system resources. Although it has a lot of advantages, it has one big disadvantage. It requires the virus signature to be extracted by the experts and stored in a database called “virus signature database”. This virus signature database has to be updated by the anti-virus developers and the end users periodically in order to deal with the latest viruses.

A typical virus …