Results 1 - 10
of
22
Bounding the Lifetime of Sensor Networks Via Optimal Role Assignments
, 2002
"... A key challenge in ad-hoc, data-gathering wireless sensor networks is achieving a lifetime of several years using nodes that carry merely hundreds of joules of stored energy. In this paper, we explore the fundamental limits of energy-efficient collaborative data-gathering by deriving upper bounds on ..."
Abstract
-
Cited by 215 (0 self)
- Add to MetaCart
A key challenge in ad-hoc, data-gathering wireless sensor networks is achieving a lifetime of several years using nodes that carry merely hundreds of joules of stored energy. In this paper, we explore the fundamental limits of energy-efficient collaborative data-gathering by deriving upper bounds on the lifetime of increasingly sophisticated sensor networks.
Real-Time Video Analysis on an Embedded Smart Camera for Traffic Surveillance
- In Proceedings of the 10th IEEE Real-Time and Embedded Technology and Applications Symposium
, 2004
"... A smart camera combines video sensing, high-level video processing and communication within a single embedded device. Such cameras are key components in novel surveillance systems. This paper reports on a prototyping development of a smart camera for traffic surveillance. We present its scalable arc ..."
Abstract
-
Cited by 40 (19 self)
- Add to MetaCart
(Show Context)
A smart camera combines video sensing, high-level video processing and communication within a single embedded device. Such cameras are key components in novel surveillance systems. This paper reports on a prototyping development of a smart camera for traffic surveillance. We present its scalable architecture comprised of a CMOS sensor, digital signal processors (DSP), and a network processor. We further discuss the mapping of high-level video processing algorithms to embedded DSP-based platforms and identify typical pitfalls for the porting of software from desktops to embedded platforms. Our mapping strategies are demonstrated on an algorithm for automatic detection of stationary vehicles. This algorithm is migrated from a Matlabbased prototyping implementation to an embedded DSP implementation in our smart camera. Our implemented smart camera prototype streams the video data over an IP-network to a central monitoring station and is able to detect stationary vehicles and blocking cargo on highways within the required real-time constraints of six seconds.
Architectural and Compiler Strategies for Dynamic Power Management in the COPPER Project
- in the COPPER project. International Workshop on Innovative Architecture
, 2001
"... For a range of embedded system applications in mission critical and energy constrained scenarios it is important to be able to dynamically control power consumption in response to changing power availability. In this paper, we present our approach to dynamic adaptation of system power consumption an ..."
Abstract
-
Cited by 16 (6 self)
- Add to MetaCart
(Show Context)
For a range of embedded system applications in mission critical and energy constrained scenarios it is important to be able to dynamically control power consumption in response to changing power availability. In this paper, we present our approach to dynamic adaptation of system power consumption and application performance through microarchitectural and software strategies. In particular, we discuss our techniques for compiler controlled dynamic register file reconfiguration and profile-driven dynamic clock frequency and voltage scaling. We evaluate the effectiveness of power scheduling heuristics based on these techniques in complying with desired power and performance constraints for a given application.
Energy-Aware Implementation of Hard-Real-Time Systems Upon Multiprocessor Platforms
- In Proceedings of the ISCA 16th International Conference on Parallel and Distributed Computing Systems
, 2002
"... Multiprocessor implementations of real-time systems tend to be more energy-ecient than uniprocessor implementations: since the power consumed by a CMOS processor is approximately proportional to the cube of the speed or computing capacity at which the processor executes, the total power consumed ..."
Abstract
-
Cited by 8 (1 self)
- Add to MetaCart
(Show Context)
Multiprocessor implementations of real-time systems tend to be more energy-ecient than uniprocessor implementations: since the power consumed by a CMOS processor is approximately proportional to the cube of the speed or computing capacity at which the processor executes, the total power consumed by an m-processor multiprocessor platform is approximately (1=m ) times the power consumed by a uniprocessor platform of the same computing capacity. However several factors, including the non-existence of optimal multiprocessor scheduling algorithms, combine to prevent all the computing capacity of a multiprocessor platform from being guaranteed available for executing the real-time workload. In this paper, this tradeo | that while increasing the number of processors results in lower energy consumption for a given computing capacity, the fraction of the capacity of a multiprocessor platform that is guaranteed available for executing real-time work decreases as the number of processors increases | is explored in detail.
A framework for spatio-temporal query processing over wireless sensor networks
- In DMSN ’04: Proceeedings of the 1st international workshop on Data management for sensor networks
, 2004
"... Wireless sensor networks consist of nodes with the ability to measure, store, and process data, as well as to communicate wirelessly with nodes located in their wireless range. Users can issue queries over the network, e.g., retrieve information from nodes within a specified region, in applications ..."
Abstract
-
Cited by 7 (1 self)
- Add to MetaCart
(Show Context)
Wireless sensor networks consist of nodes with the ability to measure, store, and process data, as well as to communicate wirelessly with nodes located in their wireless range. Users can issue queries over the network, e.g., retrieve information from nodes within a specified region, in applications such as environmental monitoring. Since the sensors have typically only a limited power supply, energy-efficient processing of the queries over the network is an important issue. In this paper, we introduce a general framework for distributed processing of spatio-temporal queries in a sensor network that has two main phases: (1) routing the query to the spatial area specified in the query; (2) collecting and processing the information from the nodes relevant to the query. Within this framework, different algorithms can be designed independently for each of the two phases. We also propose novel algorithms for this framework, one for the first phase and two for the second phase. In an extensive experimental evaluation we study the performance of these algorithms in terms of energy consumption, under varying conditions. The results allow us to recommend the most energy efficient solution, given a network and a spatiotemporal query. 1
An analysis of spatio-temporal query processing in sensor networks
- In International Conference on Data Engineering Workshops
, 2005
"... Sensor networks are an emerging technology that provide new means to monitor and understand various phenomena. Nodes in a sensor network typically have a limited power supply, thus energy-efficient processing of the queries over the network is a critical issue. We propose analytical models to evalua ..."
Abstract
-
Cited by 4 (0 self)
- Add to MetaCart
(Show Context)
Sensor networks are an emerging technology that provide new means to monitor and understand various phenomena. Nodes in a sensor network typically have a limited power supply, thus energy-efficient processing of the queries over the network is a critical issue. We propose analytical models to evaluate the performance of three methods for processing historical spatio-temporal queries in sensor networks. The models allow us to better understand the tradeoffs of the investigated method, as well as to recommend the most energy efficient one at query time. 1.
Intelligent Antenna Sharing and User Cooperation
- Media Laboratory, Massachusetts Institute of Technology, Spring
, 2005
"... This thesis will study the issue of user cooperation and antenna sharing to improve wireless communication, network (autonomous) time keeping and network (autonomous) topology estimation. Practical schemes are proposed, analyzed and implemented using low cost embedded radios. This thesis tests the f ..."
Abstract
-
Cited by 4 (2 self)
- Add to MetaCart
This thesis will study the issue of user cooperation and antenna sharing to improve wireless communication, network (autonomous) time keeping and network (autonomous) topology estimation. Practical schemes are proposed, analyzed and implemented using low cost embedded radios. This thesis tests the following hypothesis: cooperative communication provides for more reliable communication under certain conditions, requires less transmission power and decreases interference to neigboring communications, when compared to point-to-point, non-cooperative communication. Therefore, cooperation can improve the
Efficient power management in real-time embedded systems
- in Emerging Technologies and Factory Automation, EFTA ’03
, 2003
"... Abstract — Power consumption became a crucial problem in the development of mobile devices, especially those that are communication intensive. In these devices, it is imperative to reduce the power consumption devoted to maintaining a communication link during data transmission/reception. The applic ..."
Abstract
-
Cited by 3 (0 self)
- Add to MetaCart
(Show Context)
Abstract — Power consumption became a crucial problem in the development of mobile devices, especially those that are communication intensive. In these devices, it is imperative to reduce the power consumption devoted to maintaining a communication link during data transmission/reception. The application of dynamic power management methodologies has contributed to the reduction of power consumption in general purpose computer systems. However, to further reduce power consumption in communication intensive real-time embedded devices we have to consider the state of the computation and external events in addition to power management policies. In this paper we propose a model of an Extended Power State Machine (EPSM), where we adapt a Power State Machine to include the state of an embedded program in the power state machine formulation. This EPSM model is used to adapt the Quality of Service (QoS) in communication intensive devices to ensure low power consumption. In such development, a middleware layer fits in the system’s architecture, being responsible for intercepting the data communication and implementing the EPSM. Also, a software tool was developed, allowing the Middleware Code to be generated based on the State Machine. A case study demonstrates the application of the proposed model to a real situation. I.
An Efficient Algorithm for Nonpreemptive Periodic Task Scheduling under Energy Constraints
"... In this paper, we address the energy-aware DVS scheduling problems for non-preemptive periodic task sets in real-time systems. Based on Greedy method, we propose a novel heuristic, Average Power Directed (APD), to maximize the system value under energy constraints, as well as keep the system functio ..."
Abstract
-
Cited by 2 (0 self)
- Add to MetaCart
(Show Context)
In this paper, we address the energy-aware DVS scheduling problems for non-preemptive periodic task sets in real-time systems. Based on Greedy method, we propose a novel heuristic, Average Power Directed (APD), to maximize the system value under energy constraints, as well as keep the system functional during the whole mission period. Under the energy constrained situation given in this paper, experiments on large number of task sets demonstrate that compared with Greedy method, APD method increased the system value by average 35.1%. Even compared with Genetic Algorithm (GA), the APD method achieves improvement by 7.3%.When the system becomes tighter energy constrained, the energy efficiency of APD increases rapidly within large scope, which proves the energy awareness of this method. APD method has high performance and linear complexity, which facilitate it an efficient energy-aware task scheduling algorithm.
