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international ieee/EMBS conference on Neural Engineering, CNE

作者： Federica Sibella Marta Parazzini Alessandro Pesatori Alessia Paglialonga Michele Norgia Paolo Ravazzani Gabriella Tognola CNR Institute of Biomedical Engineering Milan Italy Department of Electronics and Information CNR Institute of Biomedical Engineering CNR-IEITT Polytechnic University of Milan Milan Italy CNR Institute of Biomedical Engineering Department of Biomedical Engineering Polytechnic University of Milan Milan Italy Department of Electronics and Information CNR-IEIIT Polytechnic University of Milan Milan Italy

Electric potential field distribution induced in the physiological tissues by electrical stimulation through a cochlear implant electrode array, was calculated by modeling the electrical properties of both the human cochlea and the electrode array, using a finite element method. Simulations were done under different stimulation conditions: by considering different electrode configurations and by activating different electrodes along the stimulating array. These parameters were found to affect the resulting field potentials. Results of this study provide a deeper knowledge of the relationship between the stimulation parameters and the actually delivered electric field, which is crucial to develop more efficient and spatially focused excitations of cochlear neural tissues

关键词： Computational modeling distributed computing Electric potential Cochlear implants Electrodes Biomedical engineering Ear Acoustic pulses Frequency Humans

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Web-based information technologies and distributed systems (WITDS)

Proceedings - International Conference on Signal Image Techn...

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Proceedings - international conference on Signal Image Technologies and Internet Based systems, SITIS 2007 2007年 xxviii页

作者： Andres, Frederic Grosky, William National Institute of Informatics 2-1-2 Hitotsubashi Chiyoda-ku Tokyo 101-8430 Japan Department of Computer and Information Science University of Michigan-Dearborn 4901 Evergreen Road Dearborn MI 48128 United States

No abstract available

ISBN: (纸本)9780769531229

No abstract available

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Periodic Global Broadcast Time Synchronization (PGB-TS) for TDMA Based sensor Networks

Periodic Global Broadcast Time Synchronization (PGB-TS) for ...

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international conference on Recent Advances in Space Technologies (RAST)

作者： Ilker Bekmezci Fatih Alagoz M. Gokcen Arslan Turkish Air Force Academy Yesiyurt-Istanbul Turkey Boğaziçi University Istanbul Turkey

Wireless sensor networks become a new alternative for satellite systems to sense fine grained small size subjects. Time synchronization is an important aspect of distributed systems including wireless sensor networks (WSNs). Traditional time synchronization methods are mostly optimized for scalability and precision. We propose a Periodic Global Broadcast Time Synchronization (PGB-TS) mechanism for TDMA based WSNs to maximize energy efficiency. PGB-TS assumes that the sink can send periodic broadcast to all sensor nodes. sensor nodes receive the global reference broadcast and synchronize themselves to the sink PGB-TS estimates clock drift with linear regression and accepts receive error. Energy consumption of radio circuit of a sensor network is modeled analytically. Simulation results show that PGB-TS consumes significantly less energy at the expense of somewhat lowered precision. Unfortunately, because of its lower precision, energy consumption of a sensor network with PGB-TS increases with the increased number of children. To avoid the dependency in the number of children, we also propose to employ a new Data Indication Slot Mechanism (DISM) into PGB-TS. Beneficially, DISM prevents redundant checks at the expense of possible overhearing situations. Analytical model for the proposed PGB-TS with DISM is supported by the simulation results.

关键词： Time division multiple access Synchronization Wireless sensor networks Satellite broadcasting Radio broadcasting Energy consumption Analytical models Optimization methods Scalability Energy efficiency

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Wireless Microclimate sensor

Wireless Microclimate Sensor

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Intelligent sensors, sensor Networks and Information Processing conference (ISSNIP)

作者： David Grant Adnan Al-Anbuky Electrical & Electronics Engineering Auckland University of Technology Auckland New Zealand

The paper discusses the development of wireless microclimate sensor. The sensor forms the generic component of a microclimate wireless sensor network (WSN). The network is based on ieee 802.15.4 low power wireless protocol supported by ZigBee stack. The key objective of the network is to support remote monitoring and management of large orchards. The designed sensor together with a locally developed cell modem facilitate the main components for defining a microclimate wireless sensor network that could be accessed remotely. The developed sensor takes care of the critical environmental sensing for the horticultural application needs. It also takes care of energy management and self- replenishment. Preliminary results of the design sensor reflect good performance in coverage of large horticultural fields at a reasonably low cost. Five Sunlight hours a day would keep the sensor functional through its storage mechanism. The architecture allows for both power and location awareness. Identification of the field areas that require attention could be made through either light emission or embedded location awareness algorithm. Range of view for the frost alarm system would be in the region of 500 meters. Initial testing reflects promising results.

关键词： Wireless sensor networks Mobile radio mobility management Wireless application protocol Access protocols ZigBee Remote monitoring Modems Energy management Costs Alarm systems

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Continuous Assessment of Gait Velocity in Parkinson's Disease from Unobtrusive Measurements

Continuous Assessment of Gait Velocity in Parkinson's Diseas...

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international ieee/EMBS conference on Neural Engineering, CNE

作者： Misha Pavel Tamara Hayes Ishan Tsay Deniz Erdogmus Anindya Paul Nicole Larimer Holly Jimison John Nutt Biomedical Engineering and Medical Informatics Oregon Health and Sciences University USA Biomedical Engineering OHSU USA OHSU USA Biomedical Engineering and Computer Science and Electrical Engineering OHSU USA Medical Informatics and Biomedical Engineering OHSU USA Neurology OHSU USA Biomedical Engineering at OHSU

The ability to assess the neurological state of patients with neurodegenerative diseases on a continuous basis is an important component of future care for these chronically ill patients. In this paper we describe a set of algorithms to infer gait velocity and its variability using data from an unobtrusive sensor network by incorporating a simple dynamic description of a patient's movements within his or her residence. The sensors include a combination of passive motion detectors and active radio frequency identification tags. The dynamic model is a simple 4 state hidden Markov model. We investigated the ability of this model to assess gait velocity and its variability using data from a six month pilot study of several patients with early stage Parkinson's disease

关键词： Parkinson's disease Velocity measurement Testing sensor systems Hidden Markov models Neural engineering Informatics Dementia USA Councils Medical treatment

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Efficient Detection of distributed Constraint Violations

Efficient Detection of Distributed Constraint Violations

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international conference on Data Engineering

作者： Shipra Agrawal Supratim Deb K. V. M. Naidu Rajeev Rastogi Stanford University Stanford CA USA Bell Labs Research Bangalore INDIA

ISBN: (纸本)1424408024

In many distributed environments, the primary function of monitoring software is to detect anomalies, i.e., instances when system behavior deviates substantially from the norm. In this paper, we propose communication-efficient schemes for the anomaly detection problem, which we model as one of detecting the violation of global constraints defined over distributed system variables. Our approach eliminates the need to continuously track the global system state by decomposing global constraints into local constraints that can be checked efficiently at each site. Only in the occasional event that a local constraint is violated, do we resort to more expensive global constraint checking. We show that the problem of selecting the local constraints, based on frequency distribution of individual system variables, so as to minimize the communication cost is NP-hard. We propose approximation algorithms for computing provably near-optimal (in terms of the number of messages) local constraints. Experimental results with real-life network traffic data sets demonstrate that our technique can reduce message communication overhead by as much as 70% compared to existing data distribution-agnostic approaches.

关键词： Monitoring Frequency Costs Approximation algorithms Telecommunication traffic IP networks sensor systems TCPIP Computer crime Detection algorithms

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Fleck - A platform for real-world outdoor sensor networks

Fleck - A platform for real-world outdoor sensor networks

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Intelligent sensors, sensor Networks and Information Processing conference (ISSNIP)

作者： P. Sikka P. Corke L. Overs P. Valencia T. Wark Autonomous Systems Laboratory CSIRO Brisbane Australia CSIRO ICT Centre Autonomous Systems Laboratory Brisbane Australia

This paper presents the design of the Fleck platform for building real-world outdoor sensor networks. Fleck1 and Fleck2 have been successfully deployed in several long-term outdoor sensor networks. The Fleck3 is the latest member of the platform. The power input stage of the Fleck3 has been simplified and now provides the ability to compute both the energy coming in and the energy being consumed. This makes possible the implementation of sophisticated distributed energy-aware applications. Both rechargeable batteries (with over-charge protection) and super-capacitors can be used as the primary source of power. The Fleck3 incorporates a real-time clock. At the expense of a small current drain, the real-time clock provides several advantages. It allows the Fleck3 to be placed into very deep sleep, reducing the overall energy consumption down to 30 micro-Amps. It also allows the network as a whole to maintain a better sense of time and reduces the time-keeping overhead on the micro-controller. The Fleck3 incorporates a packet-based radio from Nordic. This radio is more energy efficient than earlier generations and significantly reduces the communications overhead on the micro-controller. It also provides a better radio front-end, with a range of about 1 km with normal, zero-gain quarter-wavelength antennas in the 915 MHz band. The Fleck platform supports a large variety of sensor interface boards, including a companion board incorporating a TPM chip from Atmel for applications where security is important. These features make the Fleck platform a very strong candidate for outdoor sensor networks.

关键词： Batteries Clocks Monitoring Narrowband sensor systems Hardware Agriculture Microcontrollers Wideband Voltage

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Near optimal sensor selection in the Columbia river (CORIE) observation network for data assimilation using genetic algorithms 07

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Proceedings of the 3rd ieee international conference on distributed computing in sensor systems

作者： Thanh Dang Sergey Frolov Nirupama Bulusu António Baptista Wu-Chi Feng Portland State University Portland OR Oregon Health and Science University Beaverton OR

ISBN: (纸本)9783540730897

CORIE is a pilot environmental observation and forecasting system (EOFS) for the Columbia River. The goal of CORIE is to characterize and predict complex circulation and mixing processes in a system encompassing the lower river, the estuary, and the near-ocean using a multi-scale data assimilation *** challenge for scientists is to maintain the accuracy of their modeling system while minimizing resource usage. In this paper, we first propose a metric for characterizing the error in the CORIE data assimilation model and study the impact of the number of sensors on the error reduction. Second, we propose a genetic algorithm to compute the optimal configuration of sensors that reduces the number of sensors to the minimum required while maintaining a similar level of error in the data assimilation model. We verify the results of our algorithm with 30 runs of the data assimilation model. Each run uses data collected and estimated over a two-day period. We can reduce the sensing resource usage by 26.5% while achieving comparable error in data assimilation. As a result, we can potentially save 40 thousand dollars in initial expenses and 10 thousand dollars in maintenance expense per *** algorithm can be used to guide operation of the existing observation network, as well as to guide deployment of future sensor stations. The novelty of our approach is that our problem formulation of network configuration is influenced by the data assimilation framework which is more meaningful to domain scientists, rather than using abstract sensing models.

关键词： genetic algorithm network configuration coastal monitoring data assimilation sensor selection

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A Quadratic Optimization Method for Connectivity and Coverage Control in Backbone-Based Wireless Networks

A Quadratic Optimization Method for Connectivity and Coverag...

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Intelligent sensors, sensor Networks and Information Processing conference (ISSNIP)

作者： Jaime Llorca Mehdi Kalantari Stuart D. Milner Christopher C. Davis Electrical and Computer Engineering Department University of Maryland College Park MD USA

The use of directional wireless communications to form flexible mesh backbone networks, which provide broadband connectivity to capacity-limited wireless networks or hosts, promises to circumvent the scalability limitations of traditional homogeneous wireless networks. The main challenge in the design of directional wireless backbone (DWB) networks is to assure backbone network requirements such as coverage and connectivity in a dynamic wireless environment. This paper considers the use of mobility control, as the dynamic reposition of backbone nodes, to provide assured coverage-connectivity in dynamic environments. This paper presents a novel approach to the joint coverage-connectivity optimization problem by formulating it as a quadratic minimization problem. Quadratic cost functions for network coverage and backbone connectivity are defined in terms of the square distance between neighbor nodes, which are related to the actual energy usage of the network system. Our formulation allows the design of self-organized network systems which autonomously achieve energy minimizing configurations driven by local forces exerted on network nodes. The net force on a backbone node is defined as the negative energy gradient at the location of the backbone node. A completely distributed algorithm is presented that allows backbone nodes to adjust their positions based on information about neighbors' position only. We present initial simulation results that show the effectiveness of our force-based mobility control algorithm to provide network configurations that optimize both network coverage and backbone connectivity in different scenarios. Our algorithm is shown to be adaptive, scalable and self-organized.

关键词： Optimization methods Wireless networks Spine Wireless mesh networks Communication system control Wireless communication Scalability Cost function distributed algorithms Force control

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sensor Relevance Establishment Problem in SharedInformation Gathering sensor Networks

Sensor Relevance Establishment Problem in SharedInformation ...

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ieee international conference on Networking, Sensing and Control

作者： Tauseef Gulrez Manolya Kavakli Interactive Systems and Virtual Reality Research Group Department of Computing and Division of ICS Macquarie University Sydney NSW Australia

In a city area network hundreds of video cameras, infrared and laser sensors are deployed for online monitoring of physical phenomenon over a geographical area. This is a popular application of sensor networks. Next generation intelligent sensing systems and networks are divided into two categories, an always-on mode -where every sensor information is piped to a base station (for resolution of a problem), and a snapshot mode -where a user queries the network for an instantaneous summary of the observed environment. Snapshot mode sensor networks are highly dependent on relevant sensing due to the accuracy required in a short time and the sensitive nature of the problem (query). This paper summarises the sensor relevance establishment problem in data acquisition. We describe its use in a framework that models the observed environment at each sensor node as a function of time, and uses an adaptive learning method to sample data with the corresponding relevance metric. We take the sensor network towards the problem by considering the relevance metric at given time step. The sensor relevance establishment problem has been split into two steps. In step one, the relevant sensor type is discovered based upon the ieee 1451.4 Transducers Electronic Data Sheets (TEDS). TEDS description model can be used to discover the sensor type and their geographical locations and other important information such as uncertainty measurement functions and information fusion rules necessary to fuse multi-sensor data. In step two, the most useful sensor selection is determined using the relevant information data metric. This step is modelled using the Kullback-Leibler Divergence (KLD) method to measure the information relevance distance between the TEDS modelled relevant sensors determined in step one. As proof of our concept we have simulated the 3D environment using a real-time distributed robotics software Player/Stage/Gazebo. The preliminary results have been demonstrated on a simple autono

关键词： Intelligent sensors sensor phenomena and characterization Infrared sensors Robot sensing systems Cities and towns Video sharing Cameras Infrared surveillance Laser modes Laser theory

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