This volume contains the papers presented at the Sixth ACM/IEEE International Conference on Cyber-Physical Systems (ICCPS 2015), which was held with the Cyber-Physical Systems Week in Seattle, Washington, USA, on 13--16 April 2015. ICCPS has been the flagship conference on Cyber-Physical Systems (CPS) that tightly couple the cyber aspects of computing and communications with the physical aspects of dynamics and engineering. ICCPS, as an integral part of CPS Week, is pleased to be co-located with its sister conferences that focus on various components of CPS including embedded systems, hybrid systems, real-time systems, and wireless sensor networks. ICCPS aims to showcase cutting-edge research that spans both the cyber and physical aspects of CPS. In the process, it will bring together engineers from various disciplines and computer scientists to create the scientific foundations, identify new principles, present novel architectures, demonstrate promising applications, and enable powerful capabilities of CPS. In addition to its traditional focus on the foundations, applications, and examples of CPS, this year ICCPS has absorbed the former High Confidence Networked Systems (HiCoNS) conference and includes its focus on secure and resilient infrastructure for CPS.
{"title":"Proceedings of the ACM/IEEE Sixth International Conference on Cyber-Physical Systems","authors":"A. Bayen, M. Branicky","doi":"10.1145/2735960","DOIUrl":"https://doi.org/10.1145/2735960","url":null,"abstract":"This volume contains the papers presented at the Sixth ACM/IEEE International Conference on Cyber-Physical Systems (ICCPS 2015), which was held with the Cyber-Physical Systems Week in Seattle, Washington, USA, on 13--16 April 2015. ICCPS has been the flagship conference on Cyber-Physical Systems (CPS) that tightly couple the cyber aspects of computing and communications with the physical aspects of dynamics and engineering. ICCPS, as an integral part of CPS Week, is pleased to be co-located with its sister conferences that focus on various components of CPS including embedded systems, hybrid systems, real-time systems, and wireless sensor networks. \u0000 \u0000ICCPS aims to showcase cutting-edge research that spans both the cyber and physical aspects of CPS. In the process, it will bring together engineers from various disciplines and computer scientists to create the scientific foundations, identify new principles, present novel architectures, demonstrate promising applications, and enable powerful capabilities of CPS. In addition to its traditional focus on the foundations, applications, and examples of CPS, this year ICCPS has absorbed the former High Confidence Networked Systems (HiCoNS) conference and includes its focus on secure and resilient infrastructure for CPS.","PeriodicalId":344612,"journal":{"name":"Proceedings of the ACM/IEEE Sixth International Conference on Cyber-Physical Systems","volume":"104 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121058580","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}
Tamara Bonaci, Junjie Yan, Jeffrey A. Herron, Tadayoshi Kohno, H. Chizeck
Applications of robotic systems have had an explosive growth in recent years. In 2008, more than eight million robots were deployed worldwide in factories, battlefields, and medical services. The number and the applications of robotic systems are expected to continue growing, and many future robots will be controlled by distant operators through wired and wireless communication networks. The open and uncontrollable nature of communication media between robots and operators renders these cyber-physical systems vulnerable to a variety of cyber-security threats, many of which cannot be prevented using traditional cryptographic methods. A question thus arises: what if teleoperated robots are attacked, compromised or taken over? In this paper, we systematically analyze cyber-security attacks against Raven II R, an advanced teleoperated robotic surgery system. We classify possible threats, and focus on denial-of-service (DoS) attacks, which cannot be prevented using available cryptographic solutions. Through a series of experiments involving human subjects, we analyze the impact of these attacks on teleoperated procedures. We use the Fitts' law as a way of quantifying the impact, and measure the increase in tasks' difficulty when under DoS attacks. We then consider possible steps to mitigate the identified DoS attacks, and evaluate the applicability of these solutions for teleoperated robotics. The broader goal of our paper is to raise awareness, and increase understanding of emerging cyber-security threats against teleoperated robotic systems.
近年来，机器人系统的应用有了爆炸性的增长。2008年，全世界有超过800万个机器人被部署在工厂、战场和医疗服务中。机器人系统的数量和应用预计将继续增长，许多未来的机器人将由远程操作员通过有线和无线通信网络控制。机器人和操作员之间通信媒体的开放性和不可控性使得这些网络物理系统容易受到各种网络安全威胁，其中许多威胁无法使用传统的加密方法进行预防。这样就产生了一个问题:如果远程操作的机器人受到攻击、破坏或被接管怎么办?在本文中，我们系统地分析了针对Raven II R的网络安全攻击，这是一种先进的远程操作机器人手术系统。我们对可能的威胁进行分类，并重点关注拒绝服务(DoS)攻击，使用可用的加密解决方案无法阻止这种攻击。通过一系列涉及人类受试者的实验，我们分析了这些攻击对远程操作程序的影响。我们使用Fitts定律作为一种量化影响的方法，并测量在遭受DoS攻击时任务难度的增加。然后，我们考虑可能的步骤来减轻已识别的DoS攻击，并评估这些解决方案对远程操作机器人的适用性。我们的论文的更广泛的目标是提高意识，并增加对远程操作机器人系统的新兴网络安全威胁的理解。
{"title":"Experimental analysis of denial-of-service attacks on teleoperated robotic systems","authors":"Tamara Bonaci, Junjie Yan, Jeffrey A. Herron, Tadayoshi Kohno, H. Chizeck","doi":"10.1145/2735960.2735980","DOIUrl":"https://doi.org/10.1145/2735960.2735980","url":null,"abstract":"Applications of robotic systems have had an explosive growth in recent years. In 2008, more than eight million robots were deployed worldwide in factories, battlefields, and medical services. The number and the applications of robotic systems are expected to continue growing, and many future robots will be controlled by distant operators through wired and wireless communication networks. The open and uncontrollable nature of communication media between robots and operators renders these cyber-physical systems vulnerable to a variety of cyber-security threats, many of which cannot be prevented using traditional cryptographic methods. A question thus arises: what if teleoperated robots are attacked, compromised or taken over? In this paper, we systematically analyze cyber-security attacks against Raven II R, an advanced teleoperated robotic surgery system. We classify possible threats, and focus on denial-of-service (DoS) attacks, which cannot be prevented using available cryptographic solutions. Through a series of experiments involving human subjects, we analyze the impact of these attacks on teleoperated procedures. We use the Fitts' law as a way of quantifying the impact, and measure the increase in tasks' difficulty when under DoS attacks. We then consider possible steps to mitigate the identified DoS attacks, and evaluate the applicability of these solutions for teleoperated robotics. The broader goal of our paper is to raise awareness, and increase understanding of emerging cyber-security threats against teleoperated robotic systems.","PeriodicalId":344612,"journal":{"name":"Proceedings of the ACM/IEEE Sixth International Conference on Cyber-Physical Systems","volume":"108 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124808937","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}
N. Ahmed, M. Campbell, D. Casbeer, Yongcan Cao, Derek B. Kingston
This work considers the challenging problem of simultaneous modeling and fusion of 'soft data' generated by a network of 'human sensors' for spatial state estimation tasks, such as lost target search or large area surveillance. Human sensors can opportunistically provide useful information to constrain difficult state estimation problems, but are imperfect information sources whose reliability cannot be easily determined in advance. Formal observation likelihood models are derived for flexible sketch-based observations, but are found to lead to analytically intractable statistical dependencies between unknown sensor parameters and spatial states of interest that cannot adequately characterized by simple point estimates. Hierarchical Bayesian models and centralized inference strategies based on Gibbs sampling are proposed to address these issues, especially in cases of sparse, noisy, ambiguous and conflicting soft data. This leads to an automatic online calibration procedure for human sensor networks, as well as conservative spatial state posteriors that naturally account for model uncertainties. Experimental outdoor target search results with real spatial human sensor data (obtained via networked mobile graphical sketch interfaces) demonstrate the proposed methodology.
{"title":"Fully bayesian learning and spatial reasoning with flexible human sensor networks","authors":"N. Ahmed, M. Campbell, D. Casbeer, Yongcan Cao, Derek B. Kingston","doi":"10.1145/2735960.2735970","DOIUrl":"https://doi.org/10.1145/2735960.2735970","url":null,"abstract":"This work considers the challenging problem of simultaneous modeling and fusion of 'soft data' generated by a network of 'human sensors' for spatial state estimation tasks, such as lost target search or large area surveillance. Human sensors can opportunistically provide useful information to constrain difficult state estimation problems, but are imperfect information sources whose reliability cannot be easily determined in advance. Formal observation likelihood models are derived for flexible sketch-based observations, but are found to lead to analytically intractable statistical dependencies between unknown sensor parameters and spatial states of interest that cannot adequately characterized by simple point estimates. Hierarchical Bayesian models and centralized inference strategies based on Gibbs sampling are proposed to address these issues, especially in cases of sparse, noisy, ambiguous and conflicting soft data. This leads to an automatic online calibration procedure for human sensor networks, as well as conservative spatial state posteriors that naturally account for model uncertainties. Experimental outdoor target search results with real spatial human sensor data (obtained via networked mobile graphical sketch interfaces) demonstrate the proposed methodology.","PeriodicalId":344612,"journal":{"name":"Proceedings of the ACM/IEEE Sixth International Conference on Cyber-Physical Systems","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126817414","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}
Lu Feng, Clemens Wiltsche, Laura R. Humphrey, U. Topcu
We propose an approach to synthesize control protocols for autonomous systems that account for uncertainties and imperfections in interactions with human operators. As an illustrative example, we consider a scenario involving road network surveillance by an unmanned aerial vehicle (UAV) that is controlled remotely by a human operator but also has a certain degree of autonomy. Depending on the type (i.e., probabilistic and/or nondeterministic) of knowledge about the uncertainties and imperfections in the operator-autonomy interactions, we use abstractions based on Markov decision processes and augment these models to stochastic two-player games. Our approach enables the synthesis of operator-dependent optimal mission plans for the UAV, highlighting the effects of operator characteristics (e.g., workload, proficiency, and fatigue) on UAV mission performance; it can also provide informative feedback (e.g., Pareto curves showing the trade-offs between multiple mission objectives), potentially assisting the operator in decision-making.
{"title":"Controller synthesis for autonomous systems interacting with human operators","authors":"Lu Feng, Clemens Wiltsche, Laura R. Humphrey, U. Topcu","doi":"10.1145/2735960.2735973","DOIUrl":"https://doi.org/10.1145/2735960.2735973","url":null,"abstract":"We propose an approach to synthesize control protocols for autonomous systems that account for uncertainties and imperfections in interactions with human operators. As an illustrative example, we consider a scenario involving road network surveillance by an unmanned aerial vehicle (UAV) that is controlled remotely by a human operator but also has a certain degree of autonomy. Depending on the type (i.e., probabilistic and/or nondeterministic) of knowledge about the uncertainties and imperfections in the operator-autonomy interactions, we use abstractions based on Markov decision processes and augment these models to stochastic two-player games. Our approach enables the synthesis of operator-dependent optimal mission plans for the UAV, highlighting the effects of operator characteristics (e.g., workload, proficiency, and fatigue) on UAV mission performance; it can also provide informative feedback (e.g., Pareto curves showing the trade-offs between multiple mission objectives), potentially assisting the operator in decision-making.","PeriodicalId":344612,"journal":{"name":"Proceedings of the ACM/IEEE Sixth International Conference on Cyber-Physical Systems","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127754961","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}
Recently there is an increasing interest in smart city. Smart city differs from digital city mostly due to the ingredients of data analytics. In such context, computer science is nowadays jointly working with physical domains; and we make the physical domains smarter by providing adding values or cost reduction; for example, there are studies on smart buildings, smart transport, smart grid, etc. Most of these studies show a joint of computer science with a single physical domain. In this work, we study a connection of two physical domains, the built environment and transport.
{"title":"Developing associations between building occupancy and traffic congestion","authors":"Yi Yuan, C. Fan, Dan Wang, Linda Fu Xiao","doi":"10.1145/2735960.2735990","DOIUrl":"https://doi.org/10.1145/2735960.2735990","url":null,"abstract":"Recently there is an increasing interest in smart city. Smart city differs from digital city mostly due to the ingredients of data analytics. In such context, computer science is nowadays jointly working with physical domains; and we make the physical domains smarter by providing adding values or cost reduction; for example, there are studies on smart buildings, smart transport, smart grid, etc. Most of these studies show a joint of computer science with a single physical domain. In this work, we study a connection of two physical domains, the built environment and transport.","PeriodicalId":344612,"journal":{"name":"Proceedings of the ACM/IEEE Sixth International Conference on Cyber-Physical Systems","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125948630","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}
Estimating the number of people within a room is important for a wide variety of applications including: HVAC load management, scheduling room allocations and guiding first responders to areas with trapped people. In this paper, we present an active sensing technique that uses changes in a room's acoustic properties to estimate the number of occupants. Frequency dependent models of reverberation and room capacity are often used when designing auditoriums and concert halls. We leverage this property by using measured changes in the ultrasonic spectrum reflected back from a wide-band transmitter to estimate occupancy. A centrally located beacon transmits an ultrasonic chirp and then records how the signal dissipates over time. By analyzing the frequency response over the chirp's bandwidth at a few known occupancy levels, we are able to extrapolate the response as the number of people in the room changes. We explore the design of an excitation signal that best senses the environment with the fewest number of training samples. Through experimentation, we show that our approach is able to capture the number of people in a wide-variety of room configurations with people counting accuracy below 10% of the maximum room capacity count with as few as two training points. Finally, we provide a simple mechanism that allows our system to recalibrate when we know the room is empty so that it can adapt dynamically over time.
{"title":"Occupancy estimation using ultrasonic chirps","authors":"Oliver Shih, Anthony G. Rowe","doi":"10.1145/2735960.2735969","DOIUrl":"https://doi.org/10.1145/2735960.2735969","url":null,"abstract":"Estimating the number of people within a room is important for a wide variety of applications including: HVAC load management, scheduling room allocations and guiding first responders to areas with trapped people. In this paper, we present an active sensing technique that uses changes in a room's acoustic properties to estimate the number of occupants. Frequency dependent models of reverberation and room capacity are often used when designing auditoriums and concert halls. We leverage this property by using measured changes in the ultrasonic spectrum reflected back from a wide-band transmitter to estimate occupancy. A centrally located beacon transmits an ultrasonic chirp and then records how the signal dissipates over time. By analyzing the frequency response over the chirp's bandwidth at a few known occupancy levels, we are able to extrapolate the response as the number of people in the room changes. We explore the design of an excitation signal that best senses the environment with the fewest number of training samples. Through experimentation, we show that our approach is able to capture the number of people in a wide-variety of room configurations with people counting accuracy below 10% of the maximum room capacity count with as few as two training points. Finally, we provide a simple mechanism that allows our system to recalibrate when we know the room is empty so that it can adapt dynamically over time.","PeriodicalId":344612,"journal":{"name":"Proceedings of the ACM/IEEE Sixth International Conference on Cyber-Physical Systems","volume":"70 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131748388","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}
Junkil Park, Radoslav Ivanov, James Weimer, M. Pajic, Insup Lee
This paper addresses the problem of detection and identification of sensor attacks in the presence of transient faults. We consider a system with multiple sensors measuring the same physical variable, where some sensors might be under attack and provide malicious values. We consider a setup, in which each sensor provides the controller with an interval of possible values for the true value. While approaches exist for detecting malicious sensor attacks, they are conservative in that they treat attacks and faults in the same way, thus neglecting the fact that sensors may provide faulty measurements at times due to temporary disturbances (e.g., a tunnel for GPS). To address this problem, we propose a transient fault model for each sensor and an algorithm designed to detect and identify attacks in the presence of transient faults. The fault model consists of three aspects: the size of the sensor's interval (1) and an upper bound on the number of errors (2) allowed in a given window size (3). Given such a model for each sensor, the algorithm uses pairwise inconsistencies between sensors to detect and identify attacks. In addition to the algorithm, we provide a framework for selecting a fault model for each sensor based on training data. Finally, we validate the algorithm's performance on real measurement data obtained from an unmanned ground vehicle.
{"title":"Sensor attack detection in the presence of transient faults","authors":"Junkil Park, Radoslav Ivanov, James Weimer, M. Pajic, Insup Lee","doi":"10.1145/2735960.2735984","DOIUrl":"https://doi.org/10.1145/2735960.2735984","url":null,"abstract":"This paper addresses the problem of detection and identification of sensor attacks in the presence of transient faults. We consider a system with multiple sensors measuring the same physical variable, where some sensors might be under attack and provide malicious values. We consider a setup, in which each sensor provides the controller with an interval of possible values for the true value. While approaches exist for detecting malicious sensor attacks, they are conservative in that they treat attacks and faults in the same way, thus neglecting the fact that sensors may provide faulty measurements at times due to temporary disturbances (e.g., a tunnel for GPS). To address this problem, we propose a transient fault model for each sensor and an algorithm designed to detect and identify attacks in the presence of transient faults. The fault model consists of three aspects: the size of the sensor's interval (1) and an upper bound on the number of errors (2) allowed in a given window size (3). Given such a model for each sensor, the algorithm uses pairwise inconsistencies between sensors to detect and identify attacks. In addition to the algorithm, we provide a framework for selecting a fault model for each sensor based on training data. Finally, we validate the algorithm's performance on real measurement data obtained from an unmanned ground vehicle.","PeriodicalId":344612,"journal":{"name":"Proceedings of the ACM/IEEE Sixth International Conference on Cyber-Physical Systems","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123538078","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}
Xiaodong Zhang, M. Clark, K. Rattan, Jonathan A. Muse
With the increasing levels of adaptation and autonomy in complex cyber-physical systems (CPS), the traditional notion that such systems can be fully tested and validated offline is becoming an impossible task. It is virtually impossible to analyze or test ahead of time all the possible parameter values resulting from the uncertainty in system operational and environmental conditions. This paper considers the problem of online controller verification in a class of first-order nonlinear uncertain systems incorporating neural network based learning algorithms. Based on several critical assumptions, an on-line neural network model is employed to ensure robustness and fault-tolerance to certain modeling uncertainty and physical faults under consideration. However, these assumptions may be violated in the presence of software faults or unanticipated physical faults in the closed-loop system, leading to unstable learning behaviors and controller malfunctions. Based on Lyapunov stability theory, a online controller verification scheme is developed to detect such unstable learning behaviors by continuously monitoring the decrease of Lyapunov functions. Adaptive thresholds for detecting malfunctions of the adaptive learning controller are derived, ensuring the robustness with respect to modeling uncertainty and neural network approximation error. Additionally, the detectability conditions are investigated, characterizing the class of detectable software faults and unanticipated hardware faults. An upper bound on the detection time of controller malfunction is also derived. Some simulation results using a two-tank system are shown to illustrate the effectiveness of the controller verification method.
{"title":"Controller verification in adaptive learning systems towards trusted autonomy","authors":"Xiaodong Zhang, M. Clark, K. Rattan, Jonathan A. Muse","doi":"10.1145/2735960.2735971","DOIUrl":"https://doi.org/10.1145/2735960.2735971","url":null,"abstract":"With the increasing levels of adaptation and autonomy in complex cyber-physical systems (CPS), the traditional notion that such systems can be fully tested and validated offline is becoming an impossible task. It is virtually impossible to analyze or test ahead of time all the possible parameter values resulting from the uncertainty in system operational and environmental conditions. This paper considers the problem of online controller verification in a class of first-order nonlinear uncertain systems incorporating neural network based learning algorithms. Based on several critical assumptions, an on-line neural network model is employed to ensure robustness and fault-tolerance to certain modeling uncertainty and physical faults under consideration. However, these assumptions may be violated in the presence of software faults or unanticipated physical faults in the closed-loop system, leading to unstable learning behaviors and controller malfunctions. Based on Lyapunov stability theory, a online controller verification scheme is developed to detect such unstable learning behaviors by continuously monitoring the decrease of Lyapunov functions. Adaptive thresholds for detecting malfunctions of the adaptive learning controller are derived, ensuring the robustness with respect to modeling uncertainty and neural network approximation error. Additionally, the detectability conditions are investigated, characterizing the class of detectable software faults and unanticipated hardware faults. An upper bound on the detection time of controller malfunction is also derived. Some simulation results using a two-tank system are shown to illustrate the effectiveness of the controller verification method.","PeriodicalId":344612,"journal":{"name":"Proceedings of the ACM/IEEE Sixth International Conference on Cyber-Physical Systems","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126023104","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}
Engine control systems include computational activities that are triggered at predetermined angular values of the crankshaft, and therefore generate a workload that tends to increase with the engine speed. To cope with overload conditions, a common practice adopted by the automotive industry is to design such angular tasks with a set of modes that switch at given rotation speeds to adapt the computational demand. For this reason, these tasks are referred to as adaptive variable-rate (AVR). This paper presents an exact response time analysis for engine control applications consisting of periodic and AVR tasks scheduled by fixed priority. The proposed analysis is first presented for task sets with a single AVR task, and then extended to consider multiple AVR tasks related to a common rotation source. A number of experimental results are reported to validate the proposed approach and compare it against an existing sufficient test.
{"title":"Response-time analysis for real-time tasks in engine control applications","authors":"Alessandro Biondi, M. Natale, G. Buttazzo","doi":"10.1145/2735960.2735963","DOIUrl":"https://doi.org/10.1145/2735960.2735963","url":null,"abstract":"Engine control systems include computational activities that are triggered at predetermined angular values of the crankshaft, and therefore generate a workload that tends to increase with the engine speed. To cope with overload conditions, a common practice adopted by the automotive industry is to design such angular tasks with a set of modes that switch at given rotation speeds to adapt the computational demand. For this reason, these tasks are referred to as adaptive variable-rate (AVR). This paper presents an exact response time analysis for engine control applications consisting of periodic and AVR tasks scheduled by fixed priority. The proposed analysis is first presented for task sets with a single AVR task, and then extended to consider multiple AVR tasks related to a common rotation source. A number of experimental results are reported to validate the proposed approach and compare it against an existing sufficient test.","PeriodicalId":344612,"journal":{"name":"Proceedings of the ACM/IEEE Sixth International Conference on Cyber-Physical Systems","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127010327","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}
Unbalanced battery cells are known to significantly degrade the performance and reliability of a large-scale battery system. In this paper, we exploit emerging reconfigurable battery packs to mitigate the cell imbalance via the joint consideration of system reconfigurability and State-of-Health (SoH) of cells. Via empirical measurements and validation, we observe that a significantly larger amount of capacity can be delivered when cells with similar SoH levels are connected in series during discharging, which in turn extends the system operation time. Based on this observation, we propose two SoH-aware reconfiguration algorithms focusing on fully and partially reconfigurable battery packs, and prove their (near) optimality. We evaluate the proposed SoH-aware reconfiguration algorithms using both experiments and simulations. The algorithms are shown to deliver about 10--30% more capacity than SoH-oblivious configuration approaches.
{"title":"SHARE: SoH-aware reconfiguration to enhance deliverable capacity of large-scale battery packs","authors":"Liang He, Y. Gu, Ting Zhu, Cong Liu, K. Shin","doi":"10.1145/2735960.2735967","DOIUrl":"https://doi.org/10.1145/2735960.2735967","url":null,"abstract":"Unbalanced battery cells are known to significantly degrade the performance and reliability of a large-scale battery system. In this paper, we exploit emerging reconfigurable battery packs to mitigate the cell imbalance via the joint consideration of system reconfigurability and State-of-Health (SoH) of cells. Via empirical measurements and validation, we observe that a significantly larger amount of capacity can be delivered when cells with similar SoH levels are connected in series during discharging, which in turn extends the system operation time. Based on this observation, we propose two SoH-aware reconfiguration algorithms focusing on fully and partially reconfigurable battery packs, and prove their (near) optimality. We evaluate the proposed SoH-aware reconfiguration algorithms using both experiments and simulations. The algorithms are shown to deliver about 10--30% more capacity than SoH-oblivious configuration approaches.","PeriodicalId":344612,"journal":{"name":"Proceedings of the ACM/IEEE Sixth International Conference on Cyber-Physical Systems","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121863712","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}
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