Homa Alemzadeh

dblp:80/7769 · DBLP profile ↗
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29ranked-venue papers
4as first author
17since 2021 · last 2026
0000-0001-5279-842XORCID · corroborated

Domains — the database's venue-derived domains; a paper can count in several

Systems, architecture and hardware · 14 · 2 first-author · 8 since 2021Artificial intelligence and machine learning · 12 · 1 first-author · 7 since 2021Security and privacy · 12 · 2 first-author · 8 since 2021Graphics, computer vision, multimedia, augmented reality and games · 5 · 3 since 2021Computer networks · 2 · 1 since 2021Software engineering, systems software and programming languages · 2Human-computer interaction and ubiquitous computing · 1 · 1 first-authorApplied, interdisciplinary, general and emerging computing · 1 · 1 first-author
YearPublicationVenuePosition
2026 Expert-Guided Prompting and Retrieval-Augmented Generation for Emergency Medical Service Question Answering
abstract
Large language models (LLMs) have shown promise in medical question answering, yet they often overlook the domain-specific expertise that professionals depend on-such as the clinical subject areas (e.g., trauma, airway) and the certification level (e.g., EMT, Paramedic). Existing approaches typically apply general-purpose prompting or retrieval strategies without leveraging this structured context, limiting performance in high-stakes settings. We address this gap with EMSQA, an 24.3K-question multiple-choice dataset spanning 10 clinical subject areas and 4 certification levels, accompanied by curated, subject area-aligned knowledge bases (40K documents and 2M tokens). Building on EMSQA, we introduce (i) Expert-CoT, a prompting strategy that conditions chain-of-thought (CoT) reasoning on specific clinical subject area and certification level, and (ii) ExpertRAG, a retrieval-augmented generation pipeline that grounds responses in subject area-aligned documents and real-world patient data. Experiments on 4 LLMs show that Expert-CoT improves up to 2.05% over vanilla CoT prompting. Additionally, combining Expert-CoT with ExpertRAG yields up to a 4.59% accuracy gain over standard RAG baselines. Notably, the 32B expertise-augmented LLMs pass all the computer-adaptive EMS certification simulation exams.
Xueren Ge, Sahil Murtaza, Anthony Cortez, Homa Alemzadeh
AAAI4
2026 EgoEMS: A High-Fidelity Multimodal Egocentric Dataset for Cognitive Assistance in Emergency Medical Services
abstract
Emergency Medical Services (EMS) are critical to patient survival in emergencies, but first responders often face intense cognitive demands in high-stakes situations. AI cognitive assistants, acting as virtual partners, have the potential to ease this burden by supporting real-time data collection and decision making. In pursuit of this vision, we introduce EgoEMS, the first end-to-end, high-fidelity, multimodal, multiperson dataset capturing over 20 hours of realistic, procedural EMS activities from an egocentric view in 233 simulated emergency scenarios performed by 62 participants, including 46 EMS professionals. Developed in collaboration with EMS experts and aligned with national standards, EgoEMS is captured using an open-source, low-cost, and replicable data collection system and is annotated with keysteps, timestamped audio transcripts with speaker diarization, action quality metrics, and bounding boxes with segmentation masks. Emphasizing realism, the dataset includes responder-patient interactions reflecting real-world emergency dynamics. We also present a suite of benchmarks for real-time multimodal keystep recognition and action quality estimation, essential for developing AI support tools for EMS. We hope EgoEMS inspires the research community to push the boundaries of intelligent EMS systems and ultimately contribute to improved patient outcomes.
Keshara Weerasinghe, Xueren Ge, Tessa Heick, Lahiru N. S. Wijayasingha, Anthony Cortez, Abhishek Satpathy, John A. Stankovic, Homa Alemzadeh
AAAI8
2025 Runtime Stealthy Perception Attacks against DNN-based Adaptive Cruise Control Systems
abstract
Adaptive Cruise Control (ACC) is a widely used driver assistance technology for maintaining desired speed and safe distance to the leading vehicle. This paper evaluates the security of the deep neural network (DNN) based ACC systems under runtime stealthy perception attacks that strategically inject perturbations into camera data to cause forward collisions. We present a context-aware strategy for the selection of the most critical times for triggering the attacks and a novel optimization-based method for the adaptive generation of image perturbations at runtime. We evaluate the effectiveness of the proposed attack using an actual vehicle, a publicly available driving dataset, and a realistic simulation platform with the control software from a production ACC system, a physical-world driving simulator, and interventions by the human driver and safety features such as Advanced Emergency Braking System (AEBS). Experimental results show that the proposed attack achieves 142.9 times higher success rate in causing hazards and 82.6% higher evasion rate than baselines, while being stealthy and robust to real-world factors and dynamic changes in the environment. This study highlights the role of human drivers and basic safety mechanisms in preventing attacks.
Xugui Zhou, Maxfield Kouzel, Haotian Ren, Morgan McCarty, Cristina Nita-Rotaru, Homa Alemzadeh
AsiaCCS7
2025 Safety Interventions against Adversarial Patches in an Open-Source Driver Assistance System
abstract
Drivers are becoming increasingly reliant on advanced driver assistance systems (ADAS) as autonomous driving technology becomes more popular and developed with advanced safety features to enhance road safety. However, the increasing complexity of the ADAS makes autonomous vehicles (AVs) more exposed to attacks and accidental faults. In this paper, we evaluate the resilience of a widely used ADAS against safety-critical attacks that target perception inputs. Various safety mechanisms are simulated to assess their impact on mitigating attacks and enhancing ADAS resilience. Experimental results highlight the importance of timely intervention by human drivers and automated safety mechanisms in preventing accidents in both driving and lateral directions and the need to resolve conflicts among safety interventions to enhance system resilience and reliability. [Code Available at https://doi.org/10.6084/m9.figshare.28691090]
Grant Xiao, Daehyun Lee, Lishan Yang 0001, Evgenia Smirni, Homa Alemzadeh, Xugui Zhou
DSN6
2025 KnowSafe: Combined Knowledge and Data Driven Hazard Mitigation in Artificial Pancreas Systems
abstract
Significant progress has been made in anomaly detection and run-time monitoring to improve the safety and security of cyber-physical systems (CPS). However, less attention has been paid to hazard mitigation. This paper proposes a combined knowledge and data driven approach,KnowSafe, for the design of safety engines that can predict and mitigate safety hazards resulting from safety-critical malicious attacks or accidental faults targeting a CPS controller. We integrate domain-specific knowledge of safety constraints and context-specific mitigation actions with machine learning (ML) techniques to estimate system trajectories in the far and near future, infer potential hazards, and generate optimal corrective actions to keep the system safe. Experimental evaluation on two realistic closed-loop testbeds for artificial pancreas systems (APS) and two real-world datasets for diabetes treatment demonstrates thatKnowSafeoutperforms the state-of-the-art by achieving higher accuracy in predicting system state trajectories and potential hazards, a low false positive rate, and no false negatives. It also maintains the safe operation of the simulated APS despite faults or attacks without introducing any new hazards, with a hazard mitigation success rate of 92.8%, which is at least 76% higher than solely rule-based (50.9%) and data-driven (52.7%) methods.
Xugui Zhou, Maxfield Kouzel, Chloe Smith, Homa Alemzadeh
IEEE Trans. Dependable Secur. Comput.4
2024 Test of Time Award; DSN 2024
abstract
The Test-of-Time Award recognizes two outstanding papers published 10 years ago at DSN, in the DSN proceedings (research track, practical experience report or tool papers), that have had a sustained and important impact on the theory and/or practice of dependable systems and networks computing research. DSN has several areas under its umbrella and with two awards there are conditions to recognize more than one area. In exceptional situations (not enough nominations), the time frame for awards can be extended to 10-12 years, and only one paper can be awarded, in this order.
Juan-Carlos Ruiz-Garcia 0001, Homa Alemzadeh, Jean-Charles Fabre, Jiangshan Yu, Sy-Yen Kuo, Elias P. Duarte Jr.
DSN2
2024 DKEC: Domain Knowledge Enhanced Multi-Label Classification for Diagnosis Prediction
abstract
Multi-label text classification (MLTC) tasks in the medical domain often face the longtail label distribution problem.Prior works have explored hierarchical label structures to find relevant information for few-shot classes, but mostly neglected to incorporate external knowledge from medical guidelines.This paper presents DKEC, Domain Knowledge Enhanced Classification for diagnosis prediction with two innovations: (1) automated construction of heterogeneous knowledge graphs from external sources to capture semantic relations among diverse medical entities, (2) incorporating the heterogeneous knowledge graphs in few-shot classification using a label-wise attention mechanism.We construct DKEC using three online medical knowledge sources and evaluate it on a real-world Emergency Medical Services (EMS) dataset and a public electronic health record (EHR) dataset.Results show that DKEC outperforms the state-of-the-art labelwise attention networks and transformer models of different sizes, particularly for the fewshot classes.More importantly, it helps the smaller language models achieve comparable performance to large language models.
Xueren Ge, Abhishek Satpathy, Ronald D. Williams, John A. Stankovic, Homa Alemzadeh
EMNLP5
2024 Multimodal Transformers for Real-Time Surgical Activity Prediction
abstract
Real-time recognition and prediction of surgical activities are fundamental to advancing safety and autonomy in robot-assisted surgery. This paper presents a multimodal transformer architecture for real-time recognition and prediction of surgical gestures and trajectories based on short segments of kinematic and video data. We conduct an ablation study to evaluate the impact of fusing different input modalities and their representations on gesture recognition and prediction performance. We perform an end-to-end assessment of the proposed architecture using the JHU-ISI Gesture and Skill Assessment Working Set (JIGSAWS) dataset. Our model outperforms the state-of-the-art (SOTA) with 89.5% accuracy for gesture prediction through effective fusion of kinematic features with spatial and contextual video features. It achieves the real-time performance of 1.1-1.3ms for processing a 1-second input window by relying on a computationally efficient model.
Keshara Weerasinghe, Seyed Hamid Reza Roodabeh, Kay Hutchinson, Homa Alemzadeh
ICRA4
2024 Strategic Resilience Evaluation of Neural Networks Within Autonomous Vehicle Software
Anna Schmedding, Philip Schowitz, Xugui Zhou, Yiyang Lu 0001, Lishan Yang 0001, Homa Alemzadeh, Evgenia Smirni
SAFECOMP6
2024 Camera-Independent Single Image Depth Estimation from Defocus Blur
abstract
Monocular depth estimation is an important step in many downstream tasks in machine vision. We address the topic of estimating monocular depth from defocus blur which can yield more accurate results than the semantic based depth estimation methods. The existing monocular depth from defocus techniques are sensitive to the particular camera that the images are taken from. We show how several camera-related parameters affect the defocus blur using optical physics equations and how they make the defocus blur depend on these parameters. The simple correction procedure we propose can alleviate this problem which does not require any retraining of the original model. We created a synthetic dataset which can be used to test the camera independent performance of depth from defocus blur models. We evaluate our model on both synthetic and real datasets (DDFF12 and NYU depth V2) obtained with different cameras and show that our methods are significantly more robust to the changes of cameras. Code: https://github.com/sleekEagle/defocus_camind.git
Lahiru N. S. Wijayasingha, Homa Alemzadeh, John A. Stankovic
WACV2
2024 Hybrid Knowledge and Data Driven Synthesis of Runtime Monitors for Cyber-Physical Systems
abstract
Recent advances in sensing and computing technology have led to the proliferation of Cyber-Physical Systems (CPS) in safety-critical domains. However, the increasing device complexity, shrinking technology sizes, and shorter time to market have resulted in significant challenges in ensuring the reliability, safety, and security of CPS. This article presents a hybrid knowledge and data-driven approach for designing run-time context-aware safety monitors that can detect early signs of hazards and mitigate them in CPS. We propose a framework for formal specification of unsafe system context using Signal Temporal Logic (STL) combined with two optimization approaches for scenario-specific refinement and integration of STL specifications using data collected from closed-loop CPS simulations. We demonstrate the effectiveness of our approach in simulation using an autonomous driving system (ADS) and two closed-loop artificial pancreas systems (APS) as well as a publicly-available clinical trial dataset. The results show that a safety monitor developed with the proposed approaches demonstrates up to 4.7 times increase in average prediction accuracy (F1 score) over several well-designed baseline monitors while reducing both false-positive and false-negative rates in most scenarios.
Xugui Zhou, Bulbul Ahmed, James H. Aylor, Philip Asare, Homa Alemzadeh
IEEE Trans. Dependable Secur. Comput.5
2023 Towards Surgical Context Inference and Translation to Gestures
abstract
Manual labeling of gestures in robot-assisted surgery is labor intensive, prone to errors, and requires expertise or training. We propose a method for automated and explainable generation of gesture transcripts that leverages the abundance of data for image segmentation. Surgical context is detected using segmentation masks by examining the distances and intersections between the tools and objects. Next, context labels are translated into gesture transcripts using knowledge-based Finite State Machine (FSM) and data-driven Long Short Term Memory (LSTM) models. We evaluate the performance of each stage of our method by comparing the results with the ground truth segmentation masks, the consensus context labels, and the gesture labels in the JIGSAWS dataset. Our results show that our segmentation models achieve state-of-the-art performance in recognizing needle and thread in Suturing and we can automatically detect important surgical states with high agreement with crowd-sourced labels (e.g., contact between graspers and objects in Suturing). We also find that the FSM models are more robust to poor segmentation and labeling performance than LSTMs. Our proposed method can significantly shorten the gesture labeling process (~2.8 times).
Kay Hutchinson, Zongyu Li, Ian Reyes, Homa Alemzadeh
ICRA4
2023 Poster Abstract: SenseEMS - Towards A Hand Activity Recognition and Monitoring System for Emergency Medical Services
abstract
Emergency Medical Services (EMS) providers use their hands extensively for the rescue operation and providing care to the patients in an EMS scene. Using smartwatch based sensor data, i.e., accelerometer, gyroscope, and magnetometer, we are developing SenseEMS, a system for hand operated EMS intervention detection and real-time monitoring. SenseEMS will use a hybrid deep neural network with appropriate real-time algorithms on the sensor data to detect multiple hand operated activities, i.e. CPR compressions, attaching defibrillation pads and breathing bags, and to provide quality assessment on different metrics of the activity, i.e., the rate and depth of CPR compressions. Our initial results for this ongoing research show promising accuracy. Preliminary survey with 31 anonymous EMS responders suggests that this automated system will be highly beneficial for real-scene application and EMS training.
M. Arif Imtiazur Rahman, Keshara Weerasinghe, Lahiru N. S. Wijayasingha, Homa Alemzadeh, Ronald D. Williams, John A. Stankovic
IPSN4
2023 Robotic Scene Segmentation with Memory Network for Runtime Surgical Context Inference
abstract
Surgical context inference has recently garnered significant attention in robot-assisted surgery as it can facilitate workflow analysis, skill assessment, and error detection. However, runtime context inference is challenging since it requires timely and accurate detection of the interactions among the tools and objects in the surgical scene based on the segmentation of video data. On the other hand, existing state-of-the-art video segmentation methods are often biased against infrequent classes and fail to provide temporal consistency for segmented masks. This can negatively impact the context inference and accurate detection of critical states. In this study, we propose a solution to these challenges using a Space-Time Correspondence Network (STCN). STCN is a memory network that performs binary segmentation and minimizes the effects of class imbalance. The use of a memory bank in STCN allows for the utilization of past image and segmentation information, thereby ensuring consistency of the masks. Our experiments using the publicly-available JIGSAWS dataset demonstrate that STCN achieves superior segmentation performance for objects that are difficult to segment, such as needle and thread, and improves context inference compared to the state-of-the-art. We also demonstrate that segmentation and context inference can be performed at runtime without compromising performance.
Zongyu Li, Ian Reyes, Homa Alemzadeh
IROS3
2022 Strategic Safety-Critical Attacks Against an Advanced Driver Assistance System
abstract
A growing number of vehicles are being transformed into semi-autonomous vehicles (Level 2 autonomy) by relying on advanced driver assistance systems (ADAS) to improve the driving experience. However, the increasing complexity and connectivity of ADAS expose the vehicles to safety-critical faults and attacks. This paper investigates the resilience of a widely-used ADAS against safety-critical attacks that target the control system at opportune times during different driving scenarios and cause accidents. Experimental results show that our proposed Context-Aware attacks can achieve an 83.4% success rate in causing hazards, 99.7% of which occur without any warnings. These results highlight the intolerance of ADAS to safety-critical attacks and the importance of timely interventions by human drivers or automated recovery mechanisms to prevent accidents.
Xugui Zhou, Anna Schmedding, Haotian Ren, Lishan Yang 0001, Philip Schowitz, Evgenia Smirni, Homa Alemzadeh
DSN7
2022 Runtime Detection of Executional Errors in Robot-Assisted Surgery
abstract
Despite significant developments in the design of surgical robots and automated techniques for objective evaluation of surgical skills, there are still challenges in ensuring safety in robot-assisted minimally-invasive surgery (RMIS). This paper presents a runtime monitoring system for the detection of executional errors during surgical tasks through the analysis of kinematic data. The proposed system incorporates dual Siamese neural networks and knowledge of surgical context, including surgical tasks and gestures, their distributional similarities, and common error modes, to learn the differences between normal and erroneous surgical trajectories from small training datasets. We evaluate the performance of the error detection using Siamese networks compared to single CNN and LSTM networks trained with different levels of contextual knowledge and training data, using the dry-lab demonstrations of the Suturing and Needle Passing tasks from the JIGSAWS dataset. Our results show that gesture specific task nonspecific Siamese networks obtain micro F1 scores of 0.94 (Siamese-CNN) and 0.95 (Siamese-LSTM), and perform better than single CNN (0.86) and LSTM (0.87) networks. These Siamese networks also outperform gesture nonspecific task specific Siamese-CNN and Siamese-LSTM models for Suturing and Needle Passing.
Zongyu Li, Kay Hutchinson, Homa Alemzadeh
ICRA3
2021 Data-driven Design of Context-aware Monitors for Hazard Prediction in Artificial Pancreas Systems
abstract
Medical Cyber-physical Systems (MCPS) are vulnerable to accidental or malicious faults that can target their controllers and cause safety hazards and harm to patients. This paper proposes a combined model and data-driven approach for designing context-aware monitors that can detect early signs of hazards and mitigate them in MCPS. We present a framework for formal specification of unsafe system context using Signal Temporal Logic (STL) combined with an optimization method for patient-specific refinement of STL formulas based on real or simulated faulty data from the closed-loop system for the generation of monitor logic. We evaluate our approach in simulation using two state-of-the-art closed-loop Artificial Pancreas Systems (APS). The results show the context-aware monitor achieves up to 1.4 times increase in average hazard prediction accuracy (F1score) over several baseline monitors, reduces false-positive and false-negative rates, and enables hazard mitigation with a 54% success rate while decreasing the average risk for patients.
Xugui Zhou, Bulbul Ahmed, James H. Aylor, Philip Asare, Homa Alemzadeh
DSN5
2020 EMSContExt: EMS Protocol-Driven Concept Extraction for Cognitive Assistance in Emergency Response
abstract
This paper presents a technique for automated curation of a domain-specific knowledge base or lexicon for resource-constrained domains, such as Emergency Medical Services (EMS) and its application to real-time concept extraction and cognitive assistance in emergency response. The EMS responders often verbalize critical information describing the situations at an incident scene, including patients' physical condition and medical history. Automated extraction of EMS protocol-specific concepts from responders' speech data can facilitate cognitive support through the selection and execution of the proper EMS protocols for patient treatment. Although this task is similar to the traditional NLP task of concept extraction, the underlying application domain poses major challenges, including low training resources availability (e.g., no existing EMS ontology, lexicon, or annotated EMS corpus) and domain mismatch. Hence, we develop EMSContExt, a weakly-supervised concept extraction approach for EMS concepts. It utilizes different knowledge bases and a semantic concept model based on a corpus of over 9400 EMS narratives for lexicon expansion. The expanded EMS lexicon is then used to automatically extract critical EMS protocol-specific concepts from real-time EMS speech narratives. Our experimental results show that EMSContExt achieves 0.85 recall and 0.82 F1-score for EMS concept extraction and significantly outperforms MetaMap, a state-of-the-art medical concept extraction tool. We also demonstrate the application of EMSContExt to EMS protocol selection and execution and real-time recommendation of protocol-specific interventions to the EMS responders. Here, EMSContExt outperforms MetaMap with a 6% increase and six times speedup in weighted recall and execution time, respectively.
Sarah Masud Preum, Sile Shu, Homa Alemzadeh, John A. Stankovic
AAAI3
2020 GRACE: Generating Summary Reports Automatically for Cognitive Assistance in Emergency Response
abstract
EMS (emergency medical service) plays an important role in saving lives in emergency and accident situations. When first responders, including EMS providers and firefighters, arrive at an incident, they communicate with the patients (if conscious), family members and other witnesses, other first responders, and the command center. The first responders utilize a microphone and headset to support these communications. After the incident, the first responders are required to document the incident by filling out a form. Today, this is performed manually. Manual documentation of patient summary report is time-consuming, tedious, and error-prone. We have addressed these form filling problems by transcribing the audio from the scene, identifying the relevant information from all the conversations, and automatically filling out the form. Informal survey of first responders indicate that this application would be exceedingly helpful to them. Results show that we can fill out a model summary report form with an F1 score as high as 94%, 78%, 96%, and 83% when the data is noise-free audio, noisy audio, noise-free textual narratives, and noisy textual narratives, respectively.
M. Arif Imtiazur Rahman, Sarah Masud Preum, Ronald D. Williams, Homa Alemzadeh, John A. Stankovic
AAAI4
2020 Real-Time Context-Aware Detection of Unsafe Events in Robot-Assisted Surgery
abstract
Cyber-physical systems for robotic surgery have enabled minimally invasive procedures with increased precision and shorter hospitalization. However, with increasing complexity and connectivity of software and major involvement of human operators in the supervision of surgical robots, there remain significant challenges in ensuring patient safety. This paper presents a safety monitoring system that, given the knowledge of the surgical task being performed by the surgeon, can detect safety-critical events in real-time. Our approach integrates a surgical gesture classifier that infers the operational context from the time-series kinematics data of the robot with a library of erroneous gesture classifiers that given a surgical gesture can detect unsafe events. Our experiments using data from two surgical platforms show that the proposed system can detect unsafe events caused by accidental or malicious faults within an average reaction time window of 1,693 milliseconds and F1 score of 0.88 and human errors within an average reaction time window of 57 milliseconds and F1 score of 0.76.
Mohammad Samin Yasar, Homa Alemzadeh
DSN2
2020 IMACS - an interactive cognitive assistant module for cardiac arrest cases in emergency medical service: demo abstract
abstract
IMACS is an intelligent, interactive cognitive assistant dedicated to cardiac arrest cases in Emergency Medical Service (EMS). EMS providers deal with many cardiac cases. IMACS interacts with EMS providers in real-time and collects vital information from the providers' conversation, including names of interventions, timestamps of interventions, and dosage amount. Throughout the process, IMACS provides necessary reminders and creates a summary report afterward. Using the dynamic behavioral model of two different cardiac arrest recovery protocols, we have developed a critical risk-index based approach to provide time-sensitive feedback and suggest alternatives to the providers in real-time. Our experiments reveal an F1-score of 83% with 300 test cases. A qualitative study also reflects that seven out of ten of the EMS providers rate the system as very helpful in correctly executing cardiac arrest EMS protocols.
M. Arif Imtiazur Rahman, Sarah Masud Preum, John A. Stankovic, Leon Jia, Eimara Mirza, Ronald D. Williams, Homa Alemzadeh
SenSys7
2019 A Behavior Tree Cognitive Assistant System for Emergency Medical Services
abstract
This paper presents a cognitive assistant system for emergency medical services (EMS) that can serve as a rescue robot or virtual assistant, helping with improving situational awareness of the first responders through automated collection and analysis of data from the incident scene and providing suggestions to them. The proposed system relies on a Behavior Tree (BT) framework that combines the knowledge of EMS protocol guidelines with speech recognition, natural language processing, and machine learning methods to (i) extract critical information from responders' conversations and verbalized observations, (ii) infer the incident context, and (iii) decide on safe and effective response interventions to perform. We use a data-set of 8302 real EMS call records from an urban, high volume regional ambulance agency in the U.S. to evaluate the responsiveness and cognitive ability of the system and assess the safety of the suggestions provided to the responders. The experimental results show that the developed cognitive assistant achieves an average top-3 accuracy of 89% in selecting the correct EMS protocols and an average F1-score of 71% in suggesting the protocol specific interventions while providing transparency and evidence for the suggestions.
Sile Shu, Sarah Masud Preum, Haydon M. Pitchford, Ronald D. Williams, John A. Stankovic, Homa Alemzadeh
IROS6
2018 Experimental Resilience Assessment of an Open-Source Driving Agent
abstract
Autonomous vehicles (AV) depend on the sensors like RADAR and camera for the perception of the environment, path planning, and control. With the increasing autonomy and interactions with the complex environment, there have been growing concerns regarding the safety and reliability of AVs. This paper presents a Systems-Theoretic Process Analysis (STPA) based fault injection framework to assess the resilience of an open-source driving agent, called openpilot, under different environmental conditions and faults affecting sensor data. To increase the coverage of unsafe scenarios during testing, we use a strategic software fault-injection approach where the triggers for injecting the faults are derived from the unsafe scenarios identified during the high-level hazard analysis of the system. The experimental results show that the proposed strategic fault injection approach increases the hazard coverage compared to random fault injection and, thus, can help with more effective simulation of safety-critical faults and testing of AVs. In addition, the paper provides insights on the performance of openpilot safety mechanisms and its ability in timely detection and recovery from faulty inputs.
Abu Hasnat Mohammad Rubaiyat, Yongming Qin, Homa Alemzadeh
PRDC3
2016 Targeted Attacks on Teleoperated Surgical Robots: Dynamic Model-Based Detection and Mitigation
abstract
This paper demonstrates targeted cyber-physical attacks on teleoperated surgical robots. These attacks exploit vulnerabilities in the robot's control system to infer a critical time during surgery to drive injection of malicious control commands to the robot. We show that these attacks can evade the safety checks of the robot, lead to catastrophic consequences in the physical system (e.g., sudden jumps of robotic arms or system's transition to an unwanted halt state), and cause patient injury, robot damage, or system unavailability in the middle of a surgery. We present a model-based analysis framework that can estimate the consequences of control commands through real-time computation of robot's dynamics. Our experiments on the RAVEN II robot demonstrate that this framework can detect and mitigate the malicious commands before they manifest in the physical system with an average accuracy of 90%.
Homa Alemzadeh, Daniel Chen 0001, Thenkurussi Kesavadas, Zbigniew T. Kalbarczyk, Ravishankar K. Iyer
DSN1
2016 A hardware-in-the-loop simulator for safety training in robotic surgery
abstract
This paper presents a simulation-based safety training simulator for robot assisted surgery. While adverse events occur rarely during training, they could be fatal to the patients if they happen during real surgical procedures and are not handled properly by the surgical team. In this work we propose a hardware-in-the-loop robotic surgery simulator with high fidelity of the robot motion in a simulated environment, which is capable of reproducing adverse events during surgery. The proposed simulator is built upon the Raven-II open source surgical robot, integrated with a simulated surgeon console and a safety hazard injection engine, which automatically injects faults into modules of the robot control software. We simulate representative safety hazards seen in the adverse events, related to da Vinci™ robot, reported to the FDA MAUDE database. A novel haptic feedback strategy is provided to the operator when the underlying dynamics differ from the real robot states.
Homa Alemzadeh, Daniel Chen 0001, Zbigniew T. Kalbarczyk, Ravishankar K. Iyer, Thenkurussi Kesavadas
IROS2
2015 Systems-Theoretic Safety Assessment of Robotic Telesurgical Systems
Homa Alemzadeh, Daniel Chen 0001, Zbigniew T. Kalbarczyk, Jaishankar Raman, Nancy G. Leveson, Ravishankar K. Iyer
SAFECOMP1
2014 Automated Classification of Computer-Based Medical Device Recalls: An Application of Natural Language Processing and Statistical Learning
abstract
This paper presents MedSafe, a framework for automated classification of computer-based medical device recalls. The data is collected from the U.S. Food and Drug Administration (FDA) recalls database. We combined techniques in natural language processing and statistical learning to automatically identify the computer-related recalls, by interpreting the natural language semantics of recall descriptions. We evaluated MedSafe on over 16K recall records submitted to the FDA between years 2007-2013.
Homa Alemzadeh, Raymond Hoagland, Zbigniew T. Kalbarczyk, Ravishankar K. Iyer
CBMS1
2008 Reliability in Application Specific Mesh-Based NoC Architectures
abstract
Networks on chips (NoCs) provide a mechanism for handling complex communications in the next generation of integrated circuits. At the same time, lower yield in nano-technology, makes self repair communication channels a necessity in design of digital systems. This paper proposes a reliable NoC architecture based on specific application mapped onto an NoC. This architecture is capable of recovering from permanent switch failures via replacing them by neighboring switches. This method has hardware and power consumption overhead, but significantly improves reliability and has a very little effect on the performance of the system. We suggest a reliability analysis method based on the combinatorial reliability models and use it to evaluate our proposed fault-tolerant NoC architecture.
Fatemeh Refan, Homa Alemzadeh, Saeed Safari, Paolo Prinetto, Zainalabedin Navabi
IOLTS2
2008 "Plug & Test" at System Level via Testable TLM Primitives
abstract
With the evolution of Electronic System Level (ESL) design methodologies, we are experiencing an extensive use of Transaction-Level Modeling (TLM). TLM is a high-level approach to modeling digital systems where details of the communication among modules are separated from the those of the implementation of functional units. This paper represents a first step toward the automatic insertion of testing capabilities at the transaction level by definition of testable TLM primitives. The use of testable TLM primitives should help designers to easily get testable transaction level descriptions implementing what we call a "Plug & Test" design methodology. The proposed approach is intended to work both with hardware and software implementations. In particular, in this paper we will focus on the design of a testable FIFO communication channel to show how designers are given the freedom of trading-off complexity, testability levels, and cost.
Homa Alemzadeh, Stefano Di Carlo, Fatemeh Refan, Paolo Prinetto, Zainalabedin Navabi
ITC1