{"title":"Improved Results for Guaranteeing Safety Despite Physical Errors in CPS's","authors":"J. Han, Chang-Gun Lee, Sanjoy Baruah","doi":"10.1109/RTSS55097.2022.00031","DOIUrl":"https://doi.org/10.1109/RTSS55097.2022.00031","url":null,"abstract":"A recent paper declares a ‘physical error’ to have occurred in an autonomous mobile CPS if it fails to pinpoint its location to within an acceptable degree of accuracy, and proposes an innovative approach for dealing with such physical errors without compromising safety properties. We further generalize the proposed approach to enhance its applicability to a wider range of conditions than is currently possible. We also show that some schedulability analysis that was derived in this recent paper for this approach is too optimistic, and present a fix to get rid of unwarranted optimism.","PeriodicalId":202402,"journal":{"name":"2022 IEEE Real-Time Systems Symposium (RTSS)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120905874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fixed-Parameter Analysis of Preemptive Uniprocessor Scheduling Problems","authors":"Sanjoy Baruah, Abhishek Singh","doi":"10.1109/RTSS55097.2022.00025","DOIUrl":"https://doi.org/10.1109/RTSS55097.2022.00025","url":null,"abstract":"The algorithmic technique of fixed-parameter analysis of computationally intractable problems seeks to obtain a deeper understanding of the underlying causes of the intractability, with a view to identifying conditions under which the problem becomes tractable. We apply fixed-parameter analysis to the fixed-priority and EDF scheduling of recurrent (periodic and sporadic) task systems upon preemptive uniprocessor platforms.","PeriodicalId":202402,"journal":{"name":"2022 IEEE Real-Time Systems Symposium (RTSS)","volume":"409 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116517938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wenyuan Shao, Bite Ye, Huachuan Wang, Gabriel Parmer, Yuxin Ren
{"title":"Edge-RT: OS Support for Controlled Latency in the Multi-Tenant, Real-Time Edge","authors":"Wenyuan Shao, Bite Ye, Huachuan Wang, Gabriel Parmer, Yuxin Ren","doi":"10.1109/RTSS55097.2022.00011","DOIUrl":"https://doi.org/10.1109/RTSS55097.2022.00011","url":null,"abstract":"Embedded and real-time devices in many domains are increasingly dependent on network connectivity. The ability to offload computations encourages Cost, Size, Weight and Power (C-SWaP) optimizations, while coordination over the network effectively enables systems to sense the environment beyond their own local sensors, and to collaborate globally. The promise is significant: Autonomous Vehicles (AVs) coordinating with each other through infrastructure, factories aggregating data for global optimization, and power-constrained devices leveraging offloaded inference tasks. Low-latency wireless (e.g., 5G) technologies paired with the edge cloud, are further enabling these trends. Unfortunately, computation at the edge poses significant challenges due to the challenging combination of limited resources, required high performance, security due to multi-tenancy, and real-time latency. This paper introduces Edge-RT, a set of OS extensions for the edge designed to meet the end-to-end (packet reception to transmission) deadlines across chains of computations. It supports strong security by executing a chain per-client device, thus isolating tenant and device computations. Despite a practical focus on deadlines and strong isolation, it maintains high system efficiency. To do so, Edge-RT focuses on per-packet deadlines inherited by the computations that operate on it. It introduces mechanisms to avoid per-packet system overheads, while trading only bounded impacts on predictable scheduling. Results show that compared to Linux and EdgeOS, Edge-RT can both maintain higher throughput and meet significantly more deadlines both for systems with bimodal workloads with utilization above 60%, in the presence of malicious tasks, and as the system scales up in clients.","PeriodicalId":202402,"journal":{"name":"2022 IEEE Real-Time Systems Symposium (RTSS)","volume":"275 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116556639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Andrea Nota, Selma Saidi, Dennis Overbeck, Fabian Kurtz, C. Wietfeld
{"title":"Context-based Latency Guarantees Considering Channel Degradation in 5G Network Slicing","authors":"Andrea Nota, Selma Saidi, Dennis Overbeck, Fabian Kurtz, C. Wietfeld","doi":"10.1109/RTSS55097.2022.00030","DOIUrl":"https://doi.org/10.1109/RTSS55097.2022.00030","url":null,"abstract":"Mission critical applications in domains such as Industry 4.0, autonomous vehicles or smart grids are increasingly dependent on flexible, yet highly reliable communication systems. The Fifth Generation of mobile Communication Networks (5G) promises to support critical communications on a single unified physical communication network through a novel approach known as network slicing. We focus in this work on context-based hard performance guarantees by formalizing an analytical method for bounding response times in critical systems. This approach allows to consider different contexts based on models of degradation of channel quality, and avoids a global highly pessimistic worst-case bound computed for worst possible channel conditions. We demonstrate that the proposed method for computing context-based response times guarantees successfully bounds results obtained in realistic mobility scenarios using a machine-learning based 5G simulation framework.","PeriodicalId":202402,"journal":{"name":"2022 IEEE Real-Time Systems Symposium (RTSS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127448768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Half Title Page","authors":"","doi":"10.1109/rtss55097.2022.00001","DOIUrl":"https://doi.org/10.1109/rtss55097.2022.00001","url":null,"abstract":"","PeriodicalId":202402,"journal":{"name":"2022 IEEE Real-Time Systems Symposium (RTSS)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130421322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mengyu Liu, Lin Zhang, Pengyuan Lu, Kaustubh Sridhar, Fanxin Kong, O. Sokolsky, Insup Lee
{"title":"Fail-Safe: Securing Cyber-Physical Systems against Hidden Sensor Attacks","authors":"Mengyu Liu, Lin Zhang, Pengyuan Lu, Kaustubh Sridhar, Fanxin Kong, O. Sokolsky, Insup Lee","doi":"10.1109/RTSS55097.2022.00029","DOIUrl":"https://doi.org/10.1109/RTSS55097.2022.00029","url":null,"abstract":"In Cyber-Physical Systems (CPS), integrating new technologies that interact with and control physical systems raises new security risks beyond the classical cyber security domain. These risks motivated many attack detectors that focus on the binary outcome. However, one pressing risk in CPS is hidden sensor attacks that are well-designed by powerful attackers who gained full knowledge of our systems and detector. The hidden attacks inject such a small malicious signal into sensor measurement that they can stay undetected but eventually lead to a significant deviation. Thus, to secure the CPS, we propose a detection framework to identify these sensor attacks that can drive the system's physical states to an unsafe state within a given period, even if they are not detected. First, we solve optimization problems to find the optimal hidden sensor attack that leads to the minimal distance to a pre-defined unsafe state region within an observation window for a given system and detector. Then, based on this algorithm, we perform offline profiling to search for a conditionally safe region, where the system states are guaranteed to be safe within the observation window as long as the detector does not raise any alerts. Finally, the framework can online discover potential hidden sensor attacks that endanger the system by checking if the current system state moves out of the region and raising a yellow alert. The evaluation shows that the optimal hidden sensor attack results in the minimum distance to unsafe, within a given observation window among existing hidden sensor attacks. We implemented our method on four linear simulators to show the effectiveness of our method. Additionally, we provided a discussion on the challenges of applying the proposed method to non-linear systems.","PeriodicalId":202402,"journal":{"name":"2022 IEEE Real-Time Systems Symposium (RTSS)","volume":"186 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126955983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Srijeeta Maity, Rudrajyoti Roy, A. Majumder, Soumyajit Dey, A. Hota
{"title":"Future aware Dynamic Thermal Management in CPU-GPU Embedded Platforms","authors":"Srijeeta Maity, Rudrajyoti Roy, A. Majumder, Soumyajit Dey, A. Hota","doi":"10.1109/RTSS55097.2022.00041","DOIUrl":"https://doi.org/10.1109/RTSS55097.2022.00041","url":null,"abstract":"Modern data intensive Cyber-physical Systems ubiquitously employ heterogeneous multiprocessor systems-on chips (MPSoCs) for real-time sensing, computation, and actuation. The low foot-print of such SoCs often leads to high operating temperatures beyond acceptable limits. In this context, conventional thermal management techniques such as Operating System (OS) governed frequency scaling result in drastic degradation of the quality of experience and violation of real-time requirements. In this work, we propose an analytical thermal model for heterogeneous CPU-GPU embedded platforms and demonstrate a Model Predictive Control (MPC) based scheduling strategy with a novel heuristics-based optimization technique that leverages information about future kernels to judiciously choose suitable task mapping options for minimization of the platform's peak (or maximum) temperature to prolong chip's life span while adhering to real-time performance requirements. To the best of our knowledge, this is the first work that considers future awareness along with a variety of online task mapping control actions such as partitioning, migration, and frequency tuning in the context of thermal management in heterogeneous CPU-GPU embedded platforms. We evaluate the proposed heterogeneous framework on an Odroid-XU4 board using OpenCL based workloads and demonstrate its effectiveness in reducing the platform peak temperature.","PeriodicalId":202402,"journal":{"name":"2022 IEEE Real-Time Systems Symposium (RTSS)","volume":"110 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113985752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Worst-Case Time Disparity Analysis of Message Synchronization in ROS","authors":"Ruoxiang Li, Nan Guan, Xu Jiang, Zhishan Guo, Zheng Dong, Mingsong Lv","doi":"10.1109/RTSS55097.2022.00014","DOIUrl":"https://doi.org/10.1109/RTSS55097.2022.00014","url":null,"abstract":"Multi-sensor data fusion is essential in autonomous systems to support accurate perception and intelligent decisions. To perform meaningful data fusion, input data from different sensors must be sampled at time points in close propinquity to each other, otherwise the result cannot accurately reflect the status of the physical environment. ROS (Robotic Operating System), a popular software framework for autonomous systems, provides message synchronization mechanisms to address the above problem, by buffering messages carrying data from different sensors and grouping those with similar timestamps. Although message synchronization is widely used in applications developed based on ROS, little knowledge is known about its actual behavior and performance, so it is hard to guarantee the quality of data fusion. In this paper, we model the message synchronization policy in ROS and formally analyze its worst-case time disparity (maximal difference among the timestamps of the messages grouped into the same output set). We conduct experiments to evaluate the precision of the proposed time disparity upper bound against the maximal observed time disparity in real execution, and compare it with the synchronization policy in Apollo Cyber RT, another popular software framework for autonomous driving systems. Experiment results show that our analysis has good precision and ROS outperforms Apollo Cyber RT in terms of both observed worst-case time disparity and the theoretical bound.","PeriodicalId":202402,"journal":{"name":"2022 IEEE Real-Time Systems Symposium (RTSS)","volume":"1147 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127044694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Response Time Analysis for Real-Time Global Gang Scheduling","authors":"S. Lee, Seunghoon Lee, Jinkyu Lee","doi":"10.1109/RTSS55097.2022.00018","DOIUrl":"https://doi.org/10.1109/RTSS55097.2022.00018","url":null,"abstract":"This paper aims at developing a tight schedulability analysis for real-time global gang scheduling, in which threads of each task subject to timing requirements are assigned to multiple processors in parallel (i.e., following the rigid gang task model). Focusing on the RTA (Response Time Analysis) framework known to exhibit high schedulability performance for other task models, we address two following issues: i) how to generalize the existing RTA framework to gang scheduling and utilize existing RTA components of other task models for the generalized framework, and ii) how to incorporate important characteristics of gang scheduling into the RTA framework in a systematic way to minimize the framework's pessimism in judging schedulability. By addressing the issues, our RTA framework enables to derive tight schedulability analysis for EDF, FP and potentially more scheduling algorithms for real-time global gang scheduling. Also, our simulation results demonstrate that the proposed RTA framework outperforms/complements existing studies for real-time global/non-global gang scheduling, in terms of schedulability performance.","PeriodicalId":202402,"journal":{"name":"2022 IEEE Real-Time Systems Symposium (RTSS)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125559556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}