In this paper we tackle the problem of allowing applications to request different data at different rates from different sensors of the same sensor network while still being able to run the sensor network in an effici...
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ISBN:
(纸本)9781424405060
In this paper we tackle the problem of allowing applications to request different data at different rates from different sensors of the same sensor network while still being able to run the sensor network in an efficient manner. Our approach is to merge an arbitrary number of user queries into a network query. By doing this, traffic is minimised and the sensors have better energy consumption behavior than if all user queries would have been directly sent to the network. In the paper we describe the algorithms for the transformation of queries and the resulting data streams. We also provide an extensive performance evaluation of the algorithms using sets of over hundred overlapping user queries executing on the same sensor network.
Besides the currently realized applications, Wireless sensor Networks can be put to use in logistics processes. However, current WSN software platforms cannot provide the flexibility and safety needed. This paper pres...
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ISBN:
(纸本)9781424414543
Besides the currently realized applications, Wireless sensor Networks can be put to use in logistics processes. However, current WSN software platforms cannot provide the flexibility and safety needed. This paper presents sensorScheme, a runtime environment based on semantics of the Scheme programming language, used to realize a logistics scenario. sensorScheme is a general purpose WSN platform, providing dynamic reprogramming, memory safety (sandboxing), blocking I/O, marshalled communication and compact code transport. We illustrate the use of our platform and provide experimental results that show its speed of operation and energy efficiency.
Efficiently moving sensor data from its collection to use points is both the fundamental and the most difficult challenge in wireless sensor networks, as any data movement incurs cost. In this work, we focus on routin...
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ISBN:
(纸本)9781424414543
Efficiently moving sensor data from its collection to use points is both the fundamental and the most difficult challenge in wireless sensor networks, as any data movement incurs cost. In this work, we focus on routing data to multiple, possibly mobile sinks. To deal with the dynamics of the environment arising from mobility and failures, we choose a reinforcement learning approach where neighboring nodes exchange small amounts of information allowing them to learn the next, best hop to reach all sinks. Preliminary evaluation demonstrates that our technique results in low cost routes with low overhead for the learning process.
We consider the problem of localizing random sensor networks by means of Time of Arrival capabilities. Interactions among sensors are modeled by a mass-spring system. Masses (sensors) initially have a random estimatio...
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ISBN:
(纸本)9781424414543
We consider the problem of localizing random sensor networks by means of Time of Arrival capabilities. Interactions among sensors are modeled by a mass-spring system. Masses (sensors) initially have a random estimation of their position. The knowledge of their distance from other masses is translated into connect masses with springs whose length should reach the estimated distances. This determines a set of forces to which masses are subject to. Starting from this configuration we propose several strategies reducing the overall time needed to reach the desired level of equilibrium.
Besides sensing the environment variables, the application of localization in wireless sensor networks has became an important research subject. Unlike the other range-free localization schemes which are not effective...
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This paper shows ieee 802.15.4a CSS-based localization system for wireless sensor networks. ieee 802.15.4a CSS technology can provide high accurate ranging functionality to a sensor node. However, as it measures a dis...
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ISBN:
(纸本)9781424414543
This paper shows ieee 802.15.4a CSS-based localization system for wireless sensor networks. ieee 802.15.4a CSS technology can provide high accurate ranging functionality to a sensor node. However, as it measures a distance based on Time-of-Flight(TOF) of RF signal, the system needs well designed ranging and report protocol. In this paper we show our ranging protocol and location calculation server architecture.
Context-aware applications sense, combine and reason about contextual information in order to determine and adapt to the current user's context. A very important problem associated with context is the inherent amb...
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ISBN:
(纸本)9781424414543
Context-aware applications sense, combine and reason about contextual information in order to determine and adapt to the current user's context. A very important problem associated with context is the inherent ambiguity and inaccuracy. Contextual information is typically pervaded with imperfect sensing (e.g., noise of sensor readings). A novel context fusion model that represents, determines and reasons about context based on the reliability on sensor readings is proposed. This model adopts Dynamic Bayesian Networks and Fuzzy-Set theory in order to deal with the reliability of contextual data at the context inference phase.
Wireless sensor networks are moving from academia to real world scenarios. This will involve, in the near future, the design and production of hardware platforms characterized by low-cost and small form factor As a co...
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ISBN:
(纸本)9781424414543
Wireless sensor networks are moving from academia to real world scenarios. This will involve, in the near future, the design and production of hardware platforms characterized by low-cost and small form factor As a consequence, the amount of resources available on a single node, i.e. computing power, storage, and energy, will be even more constrained than today. This paper faces the problem of storing and executing an application that exceeds the memory resources available on a single node. The proposed solution is based on the idea of partitioning the application code into a number of opportunistically cooperating modules. Each node contributes to the execution of the original application by running a subset of the application tasks and providing service to the neighboring nodes.
Existing ieee 802.11 spec. provides no error recovery mechanism (ARQ) for multicast traffic. ARQ absence in wireless networks unreliable by their nature leads to frequent packet losses, which is inappropriate for most...
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ISBN:
(纸本)9781424414543
Existing ieee 802.11 spec. provides no error recovery mechanism (ARQ) for multicast traffic. ARQ absence in wireless networks unreliable by their nature leads to frequent packet losses, which is inappropriate for most of multimedia applications. In the paper, we propose new reliable multicast mechanism supporting multimedia QoS (packet loss ratio, delay and throughput), in ieee 802.11 Wireless Local Area Networks (WLANs). This mechanism is based on the concept of multiple ACK-leaders, Le. multicast recipients responsible for data packets acknowledging. We develop an analytical model of the mechanism and use the model to study and to optimize the mechanism.
In a Wireless Mesh Network (WMN), Mesh Routers (MRs) are interconnected by wireless links and form a wireless backbone to provide ubiquitous high-speed Internet connectivity for mobile clients. The wireless backbone i...
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ISBN:
(纸本)9781424414543
In a Wireless Mesh Network (WMN), Mesh Routers (MRs) are interconnected by wireless links and form a wireless backbone to provide ubiquitous high-speed Internet connectivity for mobile clients. The wireless backbone is tightly integrated with the Internet by nodes called as Internet gateways (IGWs). In this paper, we address the IGW deployment problem which is shown to be NP-hard. We first formulate it as a linear program (LP) issue, then develop two heuristic algorithms for the purpose of cost-efficient IGW deployment. We further compare our algorithms with a leading approach by extensive simulations. Our analysis shows the effectiveness of the proposed algorithms.
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