Experimental Evidence of a Haldane Gap in an S = 2 Quasi-linear Chain Antiferromagnet

The magnetic susceptibility of the $S = 2$ quasi-linear chain Heisenberg antiferromagnet (2,$2'$-bipyridine)trichloromanganese(III), MnCl_{3}(bipy), has been measured from 1.8 to 300 K with the magnetic field, H, parallel and perpendicular to the chains. The analyzed data yield $g\approx 2$ and $J\approx 35$ K. The magnetization, M, has been studied at 30 mK and 1.4 K in H up to 16 T. No evidence of long-range order is observed. Depending on crystal orientation, $M\approx 0$ at 30 mK until a critical field is achieved ($H_{c\|} = 1.2\pm 0.2 T$ and $H_{c\bot} = 1.8\pm 0.2 T), where M increases continuously as H is increased. These results are interpreted as evidence of a Haldane gap.Comment: 11 pages, 4 figure

Intelligent Parking Management System Based on Wireless Sensor Network Technology

Wireless Sensor Networks can be considered as one of the most challenging and emerging technologies empowering the provision of enhanced services to miscellaneous application domains. The objective of this paper is to examine and present an implementation of a real-time parking management system. This system adapts efficiently into a contemporary urban environment, and eventually provides to users the ability to find and navigate easily to a free curb space. The system is comprised of a deployed sensor network based on two collaborative vehicle detection schemes supported by an event-driven processing algorithm and a web based application. The evaluation of the system is performed by conducting a number of experiments in order to select the optimal sensing modality and confirm the feasibility of the proposed application system in actual running conditions. Results demonstrate that the proposed system is capable of effectively detecting overlying automobiles and robustly distinguishing false positive indications. © 2013 IFSA

A framework for secure data delivery in wireless sensor networks

Typical sensor nodes are resource constrained devices containing user level applications, operating system components, and device drivers in a single address space, with no form of memory protection. A malicious user could easily capture a node and tamper the applications running on it, in order to perform different types of attacks. In this paper, we propose a 3-layer Security Framework composed by physical security schemes, cryptography of communication channels and live forensics protection techniques that allows for secure WSN deployments. Each of the abovementioned techniques maximizes the security levels leading to a tamper proof sensor node. By applying the proposed security framework, secure communication between nodes is guaranteed, identified captured nodes are silenced and their destructive effect on the rest of the network infrastructure is minimized due to the early measures applied. Our main concern is to propose a framework that balances its attributes between robustness, as long as security is concerned and cost effective implementation as far as resources (energy consumption) are concerned. © 2012 IFSA

PLATO - Intelligent middleware platform for the collection, analysis, processing of data from multiple heterogeneous sensor systems and application development for business intelligence

The "Internet of Things" along with the "Internet ofServices" is expected to undertake a significant role in our lives for the years to come. The versatility of its components and the ability to harvest, as well as consume, ubiquitous services in addition to information from different providers, are among the main challenges for the expansion. Main information producers will consist of networks of small smart objects. These interconnected smart nodes are equipped with different micro controllers, use different network protocols and have different operational requirements. In this paper we propose a framework that confronts all types of heterogeneities in order to manage smart nodes and their data in business intelligence applications. © 2012 IEEE

Wireless sensor network for precision agriculture

Sensors are very useful in agriculture. Irregular or insufficient rainfall can be a serious limitation to the final yield, causing low yields and even crop failure. Moreover the total amount of water cannot be assessed during the growing stages of the plants. It is possible, however, to find out how much soil moisture is present. This can help farmers in decision making about the suitable amount of irrigation water in each growing season. Furthermore the combination of soil moisture sensors with management zones may lead to increase of the final yield. The aim of this research was to calibrate and install the WATERMARK sensors in a commercial vineyard according to the Precision Agriculture practices. The results of the research proved that the WATERMARK sensors can assess the soil moisture with high accuracy (R2 = 0.85). © 2011 IEEE

i-Protect: An open source emergency management framework

Emergency management is an essential capability in modern society. As disasters can happen at any time and can differ from each other considerably, it is necessary to develop a supple framework which can comply with each situation. The aim of this paper is to provide an overview of the i-Protect Emergency Management Framework and analyze in details each of its components. As a proof of concept, we also present two case studies: an urban chemical explosion and a wildland fire simulation engine. © 2011 IEEE

An In-Air Passive Acoustic Surveillance System for Urban Threats Detection and Classification

Recent military operations in urban environments are changing the requirements imposed on sensing technologies. The final goal remains threat mapping within the area of operation, but the environmental constraints and the intrinsic nature of urban threats are radically novel. AUDIS (Acoustic Urban Threat Detector for Improved Surveillance Capabilities) consists of a novel cognitive sensor that offers flexibility and adaptivity to the encountered scenarios, while also ensuring an improvement in recognition and characterization of such ground threats. AUDIS specifically aims to increase the state-of-the-art capabilities in threat detection, localization, classification and identification, supporting urban situational awareness. To achieve this goal, the novelty also resides in the sensor concept and proposed logical architecture. AUDIS exploits the conceived sparse/arrayed antenna configuration by means of an innovative ensemble of digital processing stages that support a learning-based, fully adaptive approach to urban threat recognition and characterization. The “knowledge” on the scenario and the expected/actual threats will be collected, stored and managed, exploited and grown by AUDIS to form the “base” on which the expected capability improvements can be found