In this paper, we address the data management aspect of large-scale pervasive computingsystems. We aim at building an infrastructure that simultaneously supports many kinds of context-aware applications, ranging from...
详细信息
ISBN:
(纸本)0769522998
In this paper, we address the data management aspect of large-scale pervasive computingsystems. We aim at building an infrastructure that simultaneously supports many kinds of context-aware applications, ranging from room level up to nation level. This all-embracing approach gives rise to synergetic benefits like data reuse and sensor sharing. We identify major classes of context data and detail on their characteristics relevant for efficiently managing large amounts of it. Based on that, we argue that for large scale systems it is beneficial to have special-purpose servers that are optimized for managing a certain class of context data. In the Nexus project we have implemented five servers for different classes of context data and a very flexible federation middleware integrating all these servers. For each of them, we highlight in which way the requirements of the targeted class of data are tackled and discuss our experiences.
Over the past few years, the development of technology has allowed new advances in sensor networks that monitor the physical world The data streams produced by sensor networks have different characteristics from the d...
详细信息
ISBN:
(纸本)9780780387355
Over the past few years, the development of technology has allowed new advances in sensor networks that monitor the physical world The data streams produced by sensor networks have different characteristics from the data of traditional data processing, thus requiring new paradigms of data processing systems. Recently, a lot of research has been reported on data stream processing systems. However, there are many underlying assumptions about these systems that have not been explicitly specified In this paper, our attempt is to provide a general model and architecture for data stream processing in sensor networks. This can serve as a reference architecture to better understand and categorize research in this area.
This paper discusses prospects of commercial application of IEC61499 standard based on past experiences and the future research & development plans of TCS (NZ) Ltd. The global trends in distributed control are ana...
详细信息
ISBN:
(纸本)0780390946
This paper discusses prospects of commercial application of IEC61499 standard based on past experiences and the future research & development plans of TCS (NZ) Ltd. The global trends in distributed control are analysed along with specific requirements of industries in New Zealand. A collaborative approach is considered to be the best path to industrial incubation and adoption of the technology, thereby turning the vision of distributed control into reality and it is possible to do within the next two years.
A distributed transport service in a global Quality of Service (QoS) framework over IP based protocols is presented in this paper. A distributed strategy of dynamic transport agents located along the end-to-end path i...
详细信息
ISBN:
(纸本)9780780387355
A distributed transport service in a global Quality of Service (QoS) framework over IP based protocols is presented in this paper. A distributed strategy of dynamic transport agents located along the end-to-end path is suggested. QoS management focused on transport layer based QoS adaptation for tolerant multimedia traffic is provided by the designed mechanisms. Tradeoffs between traffic QoS requirements and network operation conditions are studied in order to improve application level QoS parameters. It is in the context of Heterogeneous Long Fat Pipe Networks(1) (HLFNs) that we show important improvements both on application QoS parameters and network resources utilization.
Most of the problems for data management in today's wireless sensor networks were already dealt with during the past thirty years of the artificial neural-networks tradition and that kind of algorithms can be easi...
详细信息
ISBN:
(纸本)9780780394452
Most of the problems for data management in today's wireless sensor networks were already dealt with during the past thirty years of the artificial neural-networks tradition and that kind of algorithms can be easily implemented to wireless sensor network platforms. These problems include the need for simple parallel distributed computation, possibility for distributed storage, fault-tolerance and in some cases the possibility of auto-classification of sensor readings. We will present data acquisition through hierarchical two-level architecture with algorithms which will use wavelets for initial data-processing of the sensory inputs and neural-networks which use unsupervised learning for categorization of the sensory inputs. They are tested on a data obtained from a set of 4 motes, equipped with seven sensors each.
Recently, the demand for real-time data services has been increasing. Many e-commerce applications and information services are requiring sophisticated real-time data support. A database is a core component for such r...
详细信息
ISBN:
(纸本)9780780387355
Recently, the demand for real-time data services has been increasing. Many e-commerce applications and information services are requiring sophisticated real-time data support. A database is a core component for such real-time applications. Important to the functionality of real-time databases is data replication, which is used to meet critical time requirements. These requirements vary with different workloads;therefore, different methods of replication control are better suited for different workloads. We examine several methods of replication control and present two new methods for distributed real-time database systems. Our methods are more ideally suited for systems with non-static periodic transaction arrival patterns and systems with random transaction arrival patterns.
The main contribution of this work is to investigate the energy expended per sensor for routing in massively-deployed sensor networks, assuming an arbitrary power decay factor a with 2 <= alpha. We also show how to...
详细信息
ISBN:
(纸本)0769523005
The main contribution of this work is to investigate the energy expended per sensor for routing in massively-deployed sensor networks, assuming an arbitrary power decay factor a with 2 <= alpha. We also show how to design coronas to optimize the per-routing-path energy expenditure.
This paper considers the problem of maintaining the coverage degree of a wireless sensor network at an application specific level while keeping the sensing units of only a subset of sensor nodes active at any time to ...
详细信息
ISBN:
(纸本)0769523005
This paper considers the problem of maintaining the coverage degree of a wireless sensor network at an application specific level while keeping the sensing units of only a subset of sensor nodes active at any time to save energy. Two distributed coverage service protocols are proposed, namely, NCP (Neighbor-Based Coverage Protocol) and GCP (Grid-Based Coverage Protocol), which identify redundant sensor nodes for the desired degree of coverage to turn off their sensing units. NCP introduces a novel method for evaluation of the coverage degree of a node's sensing region by its neighbors to determine its redundancy. GCP explores the idea of dividing the target area using a virtual hexagonal-grid during which all but one sensor node with the highest residual energy are identified as redundant for the coverage of the corresponding grid unit. Performance evaluations show that both protocols result in significant energy savings while providing differentiable coverage service in the wireless sensor network with low message and computational overhead.
In wireless sensor networks, localization systems use data from sensors which receive signals from moving targets, measure RSSI, and translate RSSI into the distance between sensor and target. We consider a localizati...
详细信息
ISBN:
(纸本)0769523005
In wireless sensor networks, localization systems use data from sensors which receive signals from moving targets, measure RSSI, and translate RSSI into the distance between sensor and target. We consider a localization system that gives an error measurement model of distance and introduce a relationship between the number of data and accuracy. Extending the lifetime of a system is needed to save the energy of sensors and collect the necessary data. In this paper we propose an efficient data collecting technique to get the accuracy required for the applications while saving energy. We verify that our proposal can efficiently collect necessary data to get accuracy in cases of random sensor placement.
One fundamental issue in wireless sensor networks is the coverage problem. In heterogeneous sensor networks composed of different types of sensors, the difference of the sensing radius of nodes augments the computatio...
详细信息
ISBN:
(纸本)3540281029
One fundamental issue in wireless sensor networks is the coverage problem. In heterogeneous sensor networks composed of different types of sensors, the difference of the sensing radius of nodes augments the computation difficulty of coverage degree. In this paper, we analyze the features of heterogeneous sensor networks and discuss the approaches to guarantee and calculate the coverage degree of the region deployed by heterogeneous sensor networks. Based on our analysis, a distributed Coverage Optimization Algorithm by which each node in the network can determine whether it should be turn active/inactive is proposed. Simulation shows that our algorithm can make the extraneous nodes inactive and minimize the number of nodes need to remain active.
暂无评论