Search results for "Wireless Sensor Network"

Optimization of Linearized Belief Propagation for Distributed Detection

2020

In this paper, we investigate distributed inference schemes, over binary-valued Markov random fields, which are realized by the belief propagation (BP) algorithm. We first show that a decision variable obtained by the BP algorithm in a network of distributed agents can be approximated by a linear fusion of all the local log-likelihood ratios. The proposed approach clarifies how the BP algorithm works, simplifies the statistical analysis of its behavior, and enables us to develop a performance optimization framework for the BP-based distributed inference systems. Next, we propose a blind learning-adaptation scheme to optimize the system performance when there is no information available a pr…

Modeling and Mitigating Errors in Belief Propagation for Distributed Detection

2021

We study the behavior of the belief-propagation (BP) algorithm affected by erroneous data exchange in a wireless sensor network (WSN). The WSN conducts a distributed multidimensional hypothesis test over binary random variables. The joint statistical behavior of the sensor observations is modeled by a Markov random field whose parameters are used to build the BP messages exchanged between the sensing nodes. Through linearization of the BP message-update rule, we analyze the behavior of the resulting erroneous decision variables and derive closed-form relationships that describe the impact of stochastic errors on the performance of the BP algorithm. We then develop a decentralized distribute…

Anomaly detection in wireless sensor networks

2016

Wireless Sensor Network can be defined as a network of integrated sensors responsible for environmental sensing, data processing and communication with other sensors and the base station while consuming low power. Today, WSNs are being used in almost every part of life. The cost effective nature of WSNs is beneficial for environmental monitoring, production facilities and security monitoring. At the same time WSNs are vulnerable to security breaches, attacks and information leakage. Anomaly detection techniques are used to detect such activities over the network that do not conform to the normal behavior of the network communication. Supervised Machine learning approach is one way to detect…

Ambulatory Treatment and Telemonitoring of Patients with Parkinson’s Disease

2011

Body sensor networks (BSN) promise to enhance quality of life in common human habitats. The very next and natural step towards the improvement of the already valuable applications based on BSN is the incorporation of body actuator devices which adapt its actuation dynamically based on the information provided by the body sensors, thus forming Body Sensor and actuator Networks (BS&AN). This paper shows how BS&AN can be exploited to create an innovative system to support the treatment of patients affected by Parkinson’s Disease (PD). The combination of clinical and technological knowledge in BS&AN allows to significantly improve the quality of life of patients suffering from PD.

A Framework to Facilitate Wireless Sensor Network Application Development

2013

Elektroniskā versija nesatur pielikumus

Hydrogeologinen WSN-ympäristömonitorointi : tapaustutkimus Kaitforsin patoalueen pohjavesien korkeusseurannan pilottijärjestelmästä

2017

Tämän pro gradu -tutkielman tavoitteena on selvittää Kaitforsin patoalueelle toteutetun pohjavesien monitorointiin Kokkolan yliopistokeskus Chydeniuksessa kehitetyn pilottijärjestelmän näkökulmasta, millaisin menetelmin vedenkorkeuksien ja veden laadun monitorointia voidaan IoT:n ja langattomien sensoriverkkojen asettamista lähtökohdista automatisoidusti suorittaa. Tämän lisäksi tutkimuksen tavoitteena on selvittää automatisoidun ympäristömonitoroinnin nykytilaa ja siihen kytkeytyviä kehityssuuntauksia. Tutkimuksessa perehdytään myös Kaitforsin patoalueelle asennetun pilottijärjestelmän IEEE 802.15.4 -standardiin perustuvaan langattoman sensoriverkon toimintaan ja siihen kytkeytyneiden sens…

Wireless Strain Gauge Network : Best-Hall Measurement Case

2014

Wireless sensor networks can be used to perform structural monitoring. Strain gauges, which can be glued on or integrated to the observed material, are the most common nondestructive sensing elements for measuring surface strain. Wireless strain gauge measurement system makes strain measurements more flexible while opening new targets of application in addition to those that traditional wired strain measuring systems can offer. We have implemented a long term strain measurement in a PVC-covered hall using wireless sensor network. In this paper we evaluate the functionality and suitability of the developed wireless system for this kind of monitoring. The paper discusses the experiences gaine…

Adaptive range-based localization algorithm based on trilateration and reference node selection for outdoor wireless sensor networks

2022

Locating the nodes of outdoor wireless sensor networks (WSNs) using (tri)lateration with a low-cost ranging technique, such as the received signal strength indicator (RSSI), often results in inaccurate location estimates. This can mostly be explained by the combined effect of distance estimate errors and localization geometry, both of which are subject to the reference nodes used. To develop techniques for reducing localization error, the distance estimate errors and localization geometry must be analyzed and taken into account. To address these challenges, this paper aims to seek ways to improve the quality of range-based trilateration localization for WSN nodes in varying outdoor conditio…

Enhancing innovation capability and business opportunities : cases of SME-oriented applied research

2012

Effects of Temperature and Humidity on Radio Signal Strength in Outdoor Wireless Sensor Networks

2015

Many wireless sensor networks operating outdoors are exposed to changing weather conditions, which may cause severe degradation in system performance. Therefore, it is essential to explore the factors affecting radio link quality in order to mitigate their impact and to adapt to varying conditions. In this paper, we study the effects of temperature and humidity on radio signal strength in outdoor wireless sensor networks. Experimental measurements were performed using Atmel ZigBit 2.4GHz wireless modules, both in summer and wintertime. We employed all the radio channels specified by IEEE 802.15.4 for 2.4GHz ISM frequency band with two transmit power levels. The results show that changes in …