Protecting informative messages over burst error channels in chain-based wireless sensor networks

Regardless of the application, the way that data and information are disseminated is an important aspect in Wireless Sensor Networks (WSNs). The wireless data dissemination protocol should often guarantee a minimum reliability requirement. In this regard and to well-balance the energy and reliability, the more important packets should be protected by more powerful error control codes than the less important ones. This information-aware capability allows a system to deliver critical information with high reliability but potentially at a higher resource cost. In this paper, we first find and evaluate the factors that may influence the importance level of a packet and then design an error control approach by adaptively selecting codes for each individual links which experience long-term-fading and for each individual packet at run-time instead of applying network-wide settings prior to deployment. Moreover, we target the poor-explored chain-based topology that is of interest for many applications (e.g. monitoring bridge, tunnel, etc.). Simulation results validate the superiority of our approach compared with a number of Reed-Solomon-based error control approaches

A trust-based probabilistic coverage algorithm for wireless sensor networks

Sensing coverage is a fundamental issue for many applications in wireless sensor networks. Due to sensors resource limitations, inherent uncertainties associated with their measurements, and the harsh and dynamic environment in which they are deployed, having a QoS-aware coverage scheme is a must. In this paper, we propose a Trust-based Probabilistic Coverage algorithm, which leverages the trust concept to tackle the uncertainties introduced by the nodes and the environment, in which they operate. We formulate this problem as an Integer Linear Programming (ILP) problem, which is able to always guarantee the required QoS despite uncertainties introduced by node and/or environment. In consideration of the limitation of ILP, we also put forward a greedy heuristic algorithm to achieve almost the same ILP results without suffering from complexities imposed by ILP. We examine our heuristic with different input parameters and compare it with the ILP approach. Simulation results are presented to verify our approaches

A reliable and real-time aggregation aware data dissemination in a chain-based wireless sensor network

Time-critical applications of Wireless Sensor Networks (WSNs) demand timely data delivery for fast identification of out-of-ordinary situations and fast and reliable delivery of notification and warning messages. Due to the low reliable links in WSNs, achieving real-time guarantees and providing reliable data is quite challenging. To ensure data reliability, traditionally various retransmission mechanisms have been used, which in turn introduce extra delay. In this paper, we propose READ, i.e., a reliable and realtime aggregation-aware data dissemination to ensure reliable and fast data delivery in a chain-based WSN. We also investigate the relatively unexplored topic of impact analysis of Time To Live (TTL) and link reliability parameters on network performance in terms of attained hit ratio for three different approaches, i.e., READ, QoS-ACA, and the stop-andwait (S-W) ARQ to assess the appropriateness of each method facing different conditions. The simulation results show READ performs better in terms of hit ratio compared with QoS-ACA and S-W ARQ when link reliability is low and packet's TTL is short. Although not being the primary goal of READ, energy consumption of the protocol is also much lower than the other two approaches

Use of wireless sensor networks for distributed event detection in disaster management applications

Recently, wireless sensor networks (WSNs) have become mature enough to go beyond being simple fine-grained continuous monitoring platforms and have become one of the enabling technologies for early-warning disaster systems. Event detection functionality of WSNs can be of great help and importance for (near) real-time detection of, for example, meteorological natural hazards and wild and residential fires. From the data-mining perspective, many real world events exhibit specific patterns, which can be detected by applying machine learning (ML) techniques. In this paper, we introduce ML techniques for distributed event detection in WSNs and evaluate their performance and applicability for early detection of disasters, specifically residential fires. To this end, we present a distributed event detection approach incorporating a novel reputation-based voting and the decision tree and evaluate its performance in terms of detection accuracy and time complexity

Quality-aware data gathering and disseminating in chain-based wireless sensor networks

Wireless Sensor Networks (WSNs) are growing in popularity for various applications and a key factor for the proliferation of this revolutionary technology is designing effective protocols to meet the quality of service requirements of the application considering deployment properties and characteristics. In the WSNs domain, so far, little focus has been given to quality of service aware data dissemination protocols for low-power wireless communications over chain-based topology. On the other hand, there is increasing interest in using WSNs in monitoring and managing risks of many long-span structural/area which features a linear sensor arrangement and thus its topology resembles a chain. The network topology of these applications has special features, such as multi-hop, long delay, long distance and low reliability. To cope with these issues, the main research focus of this thesis is to study the solutions which can ensure a combination of four important quality of services, i.e. long lifetime, coverage, reliability and timeliness, for data traffic in a chain-based topology. To this end, first we ensure quality of service to some extent at the topology level. In this regard, our contributions were mostly on topological aspects or node-level constraints, and we assigned proper role and proper activity scheduling to each node based on the amount of utility the given node offers. However, quality-aware topology control alone is not sufficient to ensure quality of services for disseminating data of many applications whose packets may convey different types or amount of information. Therefore, we concentrate on using dynamic error control schemes which are allocating the correctional power in an on-demand manner based on both the packet-level constraints and channel state. In this way and for the sake of efficiency, we put the amount of information a packet carries or the time-constrained a sensory data imposes and the state in which the channel is in, into perspective with the amount of effort (in terms of energy expenditure) that is required to reliably transmit the given packets.\ud \ud This thesis has contributed to the existing data dissemination literatures by providing new insights into the process of quality-aware collecting and disseminating data in a poorly-explored chain-based topology which is of interest for many applications especially those with linear deployment. The solutions presented throughout the chapters have the potential to quality-aware collect and disseminate data related to a wide range of WSN applications whose topology resembles a chain such as monitoring operational performance and health of bridge, tunnel, highway, railway and pipeline, thereby assisting better management and increasing safety, efficiency and comfort to the users

Breakthrough innovations: The impact of foreign acquisition of knowledge

Treballs Finals del Màster d'Economia, Facultat d'Economia i Empresa, Universitat de Barcelona, Curs: 2014-2015, Tutor: Rosina Moreno SerranoBased on the Spanish Technological Innovation Panel, this paper explores the role of R&D off shoring on innovation performance from 2004 to 2012. Specifically, we focus our attention on the impact of different types of off shoring governance models into the profitability of developing a breakthrough innovation. Our study provides evidence that forms developing a breakthrough innovation tend to beneffit more from the external acquisition of knowledge than those engaged on incremental innovations. We also find evidence that acquiring knowledge from forms outside the group is more profitable than in case they do it with forms within the group. Finally, the external acquisition of knowledge tends to present a higher return on breakthrough innovation in the case of taking such knowledge from the business sector and not from universities or research institutions

On QoS guarantees of error control schemes for data dissemination in a chain-based wireless sensor networks

Time-critical applications of Wireless Sensor Networks (WSNs) demand timely data delivery for fast identification of out-of-ordinary situations and fast and reliable delivery of notification and warning messages. Due to the low reliable links in WSNs, achieving real-time guarantees and providing reliable data is quite challenging. Reliable data dissemination is traditionally performed by applying error control mechanisms. However, these mechanisms are not always suitable for time critical applications of WSNs, in which packet burst loss occurs. In this paper, we compare different error control schemes in terms of their reliability, energy efficiency and real-timeness guarantees to assess the appropriateness of each method facing different conditions. Additionally, we introduce and evaluate an enhanced version of a real-time error control scheme, called READ-MN, in terms of its Quality of Service (QoS) guarantees

Aportaciones de la prospección geofísica al estudio del subsuelo del Berguedà y Solsonés, (pre-pirineo Catalán, N.E. de la Península Ibérica)

En este trabajo se presenta la interpretaciónpor métodos geofísicos combinados de un sector del contacto entre el Pre-Pirineo y la La zona objeto del presente estudio se halla a Depresión Central Catalana..

Energy-efficient Trust-based Aggregation in Wireless Sensor Networks

Wireless sensor networks (WSNs) are often deployed in unattended and noise-prone environments and suffer from\ud energy constraints that limit the quality and quantity of data transmission. Every decision made based on the low quality and low quantity data may have drastic consequence. Therefore, ensuring high quality of sensor data and preserving energy resources of the sensor nodes go hand in hand. In this paper, we propose ETA that is an Energy-efficient Trust based data aggregation aims to achieve reliable and energy-efficient data transmission and aggregation. We use the concept of functional reputation and trust as a means to reach reliability. Functional\ud reputation is used to select nodes that best satisfy the criteria to be an aggregator on the basis of the quality of the node. To find out the best path from every sensor node to the aggregator we take into account the link availability and residual energy of the nodes over the path. Simulation results show that even though ETA introduces some delays, overall it outperforms the other approaches in terms of reliability and lifetime