Jinzhu Chen, R. Tan, G. Xing, Xiaorui Wang, Xing Fu
{"title":"Fidelity-Aware Utilization Control for Cyber-Physical Surveillance Systems","authors":"Jinzhu Chen, R. Tan, G. Xing, Xiaorui Wang, Xing Fu","doi":"10.1109/RTSS.2010.40","DOIUrl":"https://doi.org/10.1109/RTSS.2010.40","url":null,"abstract":"Recent years have seen the growing deployments of Cyber-Physical Systems (CPSs) in many mission-critical applications such as security, civil infrastructure, and transportation. These applications often impose stringent requirements on system sensing fidelity and timeliness. However, existing approaches treat these two concerns in isolation and hence are not suitable for CPSs where system fidelity and timeliness are dependent of each other because of the tight integration of computational and physical resources. In this paper, we propose a holistic approach called Fidelity-Aware Utilization Controller (FAUC) for Wireless Cyber-physical Surveillance (WCS) systems that combine low-end sensors with cameras for large-scale ad hoc surveillance in unplanned environments. By integrating data fusion with feedback control, FAUC can enforce a CPU utilization upper bound to ensure the system's real-time schedulability although CPU workloads vary significantly at runtime because of stochastic detection results. At the same time, FAUC optimizes system fidelity and adjusts the control objective of CPU utilization adaptively in the presence of variations of target/noise characteristics. We have implemented FAUC on a small-scale WCS testbed consisting of TelosB/Iris motes and cameras. Our extensive experiments on light and acoustic target detection show that FAUC can achieve robust fidelity and real-time guarantees in dynamic environments.","PeriodicalId":202891,"journal":{"name":"2010 31st IEEE Real-Time Systems Symposium","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122404341","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":"Memory-Aware Optimal Scheduling with Communication Overhead Minimization for Streaming Applications on Chip Multiprocessors","authors":"Yi Wang, Duo Liu, Zhiwei Qin, Z. Shao","doi":"10.1109/RTSS.2010.16","DOIUrl":"https://doi.org/10.1109/RTSS.2010.16","url":null,"abstract":"In this paper, we focus on solving the problem of removing inter-core communication overhead for streaming applications on chip multiprocessors. The objective is to totally remove inter-core communication overhead while minimizing the overall memory usage. By totally removing inter-core communication overhead, a shorter period can be applied and system throughput can be improved. Our basic idea is to let tasks with intra-period data dependencies transform to inter-period data dependencies so as to overlap the execution of computation and inter-core communication tasks. To solve the problem, we first perform analysis and obtain the bounds of the times needed to reschedule each task. Then we formulate the scheduling problem as an integer linear programming (ILP) model and obtain an optimal schedule. We perform simulations on a set of benchmarks from both real-life streaming applications and synthetic task graphs. The simulation results show that the proposed approach can achieve significant reduction in schedule length and improve the memory usage compared with the previous work.","PeriodicalId":202891,"journal":{"name":"2010 31st IEEE Real-Time Systems Symposium","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115938942","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}
Yuan He, Xingfa Shen, Yunhao Liu, Lufeng Mo, Guojun Dai
{"title":"LISTEN: Non-interactive Localization in Wireless Camera Sensor Networks","authors":"Yuan He, Xingfa Shen, Yunhao Liu, Lufeng Mo, Guojun Dai","doi":"10.1109/RTSS.2010.15","DOIUrl":"https://doi.org/10.1109/RTSS.2010.15","url":null,"abstract":"Recent advances in the application field increasingly demand the use of wireless camera sensor networks (WCSNs), for which localization is a crucial task to enable various location-based services. Most of the existing localization approaches for WCSNs are essentially interactive, i.e. require the interaction among the nodes throughout the localization process. As a result, they are costly to realize in practice, vulnerable to sniffer attacks, inefficient in energy consumption and computation. In this paper we propose LISTEN, a non-interactive localization approach. Using LISTEN, every camera sensor node only needs to silently listen to the beacon signals from a mobile beacon node and capture a few images until determining its own location. We design the movement trajectory of the mobile beacon node, which guarantees to locate all the nodes successfully. We have implemented LISTEN and evaluated it through extensive experiments. The experimental results demonstrate that it is accurate, efficient, and suitable for WCSNs that consist of low-end camera sensors.","PeriodicalId":202891,"journal":{"name":"2010 31st IEEE Real-Time Systems Symposium","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114169207","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":"Overloading an IEEE 802.15.4 Point-to-Point Connection with Real-Time Messages","authors":"Marc Aoun, P. V. D. Stok","doi":"10.1109/RTSS.2010.34","DOIUrl":"https://doi.org/10.1109/RTSS.2010.34","url":null,"abstract":"The paper investigates the scheduling of packets under overload in the context of wireless building control networks. We focus on the transmission specification of the IEEE 802.15.4 standard to provide actual transmission estimates. The paper analyses the optimal conditions for sending periodic packets with 1 or 2 transmission times and fixed deadlines. Simulations provide the transceiver usage values under the calculated optimal scheduling conditions. The simulations extend the results by looking at 8 transmission times and an exponential distribution of packet release times. A counterintuitive result is the occurrence of a performance decrease with increasing deadline, other conditions remaining constant.","PeriodicalId":202891,"journal":{"name":"2010 31st IEEE Real-Time Systems Symposium","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127162255","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":"The Non-cyclic Recurring Real-Time Task Model","authors":"Sanjoy Baruah","doi":"10.1109/RTSS.2010.19","DOIUrl":"https://doi.org/10.1109/RTSS.2010.19","url":null,"abstract":"Formal models used for representing recurrent real-time processes have traditionally been characterized with a period parameter that specifies the minimum amount of time that may elapse between successive invocations of the process. However a recently proposed model called the non-cyclic GMF model has the distinctive feature that there need be no single period parameter characterizing the recurrent behavior of the task. This paper studies the implications of removing the restriction of requiring a unique period parameter to other previously-proposed models for representing recurrent processes. It is shown that removing this restriction represents a significant generalization to these prior models. Despite the added generality, however, feasibility analysis on preemptive uniprocessors remains tractable.","PeriodicalId":202891,"journal":{"name":"2010 31st IEEE Real-Time Systems Symposium","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124693241","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":"Adaptive Voice Stream Multicast Over Low-Power Wireless Networks","authors":"Liqun Li, G. Xing, Qi Han, Limin Sun","doi":"10.1109/RTSS.2010.27","DOIUrl":"https://doi.org/10.1109/RTSS.2010.27","url":null,"abstract":"Low-power Wireless Networks (LWNs) have become increasingly available for mission-critical applications such as security surveillance and disaster response. In particular, emerging low-power wireless audio platforms provide an economical solution for ad hoc voice communication in emergency scenarios. In this paper, we develop a system called Adaptive Stream Multicast (ASM) for voice communication over multi-hop LWNs. ASM is composed of several novel components specially designed to deliver robust voice quality for multiple sinks in dynamic environments: 1) an empirical model to automatically evaluate the voice quality perceived at sinks based on current network condition, 2) a feedback-based Forward Error Correction scheme where the source can adapt its coding redundancy ratio dynamically in response to the voice quality variation at sinks, 3) a Tree-based Opportunistic Routing (TOR) protocol that fully exploits the broadcast opportunities on a tree based on novel forwarder selection and coordination rules, and 4) a distributed admission control algorithm that ensures the voice quality guarantees when admitting new voice streams. ASM has been implemented on a low-power hardware platform and extensively evaluated through experiments on a testbed of 18 nodes.","PeriodicalId":202891,"journal":{"name":"2010 31st IEEE Real-Time Systems Symposium","volume":"525 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127628020","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":"Lightweight Extraction of Frequent Spatio-Temporal Activities from GPS Traces","authors":"Athanasios Bamis, A. Savvides","doi":"10.1109/RTSS.2010.33","DOIUrl":"https://doi.org/10.1109/RTSS.2010.33","url":null,"abstract":"In this paper we present a classification of human movement in physical space into spatio-temporal activities (STAs) and classes thereof. Drawing from our experiences with real human data from GPS traces we define a clustering approach for STA extraction based on the amount of motion of the user in space and time. Our solution captures these properties in a lightweight online algorithm that can run inside mobile devices. We then cluster the discovered STAs into classes based on a similarity metric that aims to identify which activities (STAs) are consistent in time. In contrast to previous approaches of discovering important places, this work also utilizes the temporal properties of the data to extract more realistic STAs and STA classes. Our work is evaluated through simulations and real GPS traces.","PeriodicalId":202891,"journal":{"name":"2010 31st IEEE Real-Time Systems Symposium","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129625488","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":"A Framework for Hierarchical Scheduling on Multiprocessors: From Application Requirements to Run-Time Allocation","authors":"G. Lipari, Enrico Bini","doi":"10.1109/RTSS.2010.12","DOIUrl":"https://doi.org/10.1109/RTSS.2010.12","url":null,"abstract":"Hierarchical scheduling is a promising methodology for designing and deploying real-time applications, since it enables component-based design and analysis, and supports temporal isolation among competing applications. In hierarchical scheduling an application is described by means of a temporal interface. The designer faces the problem of how to derive the interface parameters so to make the application schedulable, at the same time minimizing the waste of computational resources. The problem is particularly relevant in multiprocessor systems, where it is not clear yet how the interface parameters influence the schedulability of the application and allocation on the physical platform. In this paper we present three novel contributions to hierarchical scheduling for multiprocessor systems. First, we propose the Bounded-Delay Multipartition (BDM), a new interface specification model that allows the designer to balance resource usage versus flexibility in selecting the virtual platform parameters. Second, we explore the schedulability region of a real-time application on top of a generic virtual platform, and derive the interface parameter. Finally, we propose Fluid Best-Fit, an algorithm that takes advantage of the extra degree of flexibility provided by the BDM to compute the virtual platform parameters and allocate it on the physical platform. The performance of the algorithm is evaluated by simulations.","PeriodicalId":202891,"journal":{"name":"2010 31st IEEE Real-Time Systems Symposium","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133981216","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":"An Evaluation of SMT-Based Schedule Synthesis for Time-Triggered Multi-hop Networks","authors":"W. Steiner","doi":"10.1109/RTSS.2010.25","DOIUrl":"https://doi.org/10.1109/RTSS.2010.25","url":null,"abstract":"Networks for real-time systems have stringent end-to-end latency and jitter requirements. One cost-efficient way to meet these requirements is the time-triggered communication paradigm which plans the transmission points in time of the frames off-line. This plan prevents contentions of frames on the network and is called a time-triggered schedule (tt-schedule). In general the tt-scheduling is a bin-packing problem, known to be NP-complete, where the complexity is mostly driven by the freedom in topology of the network, its associated hardware restrictions, and application-imposed constraints. Multi-hop networks, in particular, require the synthesis of path-dependent tt-schedules to maintain full determinism of time-triggered communication from sender to receiver. Our experiments using the YICES SMT solver show that the scheduling problem can be solved by YICES out-of-the-box for a few hundred random frame instances on the network. A customized tt-scheduler using YICES as a back-end solver allows to increase this number of frame instances up to tens of thousands. In terms of scheduling quality, the synthesis produces up to ninety percent maximum utilization on a communication link with schedule synthesis times of about half an hour for the biggest examples we have studied. As a nice side-effect the YICES out-of-the-box approach is immediately applicable for the verification of existing (even large-scale) tt-schedules and for debugging more sophisticated tt-schedulers.","PeriodicalId":202891,"journal":{"name":"2010 31st IEEE Real-Time Systems Symposium","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116665166","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}
Soheil Samii, P. Eles, Zebo Peng, P. Tabuada, A. Cervin
{"title":"Dynamic Scheduling and Control-Quality Optimization of Self-Triggered Control Applications","authors":"Soheil Samii, P. Eles, Zebo Peng, P. Tabuada, A. Cervin","doi":"10.1109/RTSS.2010.10","DOIUrl":"https://doi.org/10.1109/RTSS.2010.10","url":null,"abstract":"Time-triggered periodic control implementations are over provisioned for many execution scenarios in which the states of the controlled plants are close to equilibrium. To address this inefficient use of computation resources, researchers have proposed self-triggered control approaches in which the control task computes its execution deadline at runtime based on the state and dynamical properties of the controlled plant. The potential advantages of this control approach cannot, however, be achieved without adequate online resource-management policies. This paper addresses scheduling of multiple self-triggered control tasks that execute on a uniprocessor platform, where the optimization objective is to find trade-offs between the control performance and CPU usage of all control tasks. Our experimental results show that efficiency in terms of control performance and reduced CPU usage can be achieved with the heuristic proposed in this paper.","PeriodicalId":202891,"journal":{"name":"2010 31st IEEE Real-Time Systems Symposium","volume":"3 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121002229","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}