REDFLAG: A Run-timE, Distributed, Flexible, Lightweight, And Generic fault detection service for data-driven wireless sensor applications

Increased interest in wireless sensor networks by scientists and engineers is forcing wireless sensor networking research to focus on application requirements. Data is available as never before in many fields of study; practitioners are now burdened with the challenge of doing data-rich research rather than being data-starved. However, in situ sensors can be prone to errors, links between nodes are often unreliable, and nodes may become unresponsive in harsh environments, leaving to researchers the onerous task of deciphering often anomalous data. Presented here is the REDFLAG fault detection service for wireless sensor applications, a Run-timE, Distributed, Flexible, detector of faults, that is also Lightweight And Generic. REDFLAG addresses the two most worrisome issues in data-driven wireless sensor applications: abnormal data and missing data. REDFLAG exposes faults as they occur by using distributed algorithms in order to conserve energy. Simulation results show that REDFLAG is lightweight both in terms of footprint and required power resources while ensuring satisfactory detection and diagnosis accuracy. Being unrestrictive, REDFLAG is generically available to a myriad of applications and scenarios. As a matter of fact, REDFLAG has been applied into a subsurface contaminant transport model to improve the model performance in the presence of erroneous sensor data.     

A photoluminescence-based quantum semiconductor biosensor for rapid in situ detection of Escherichia coli

This work describes a novel method of detecting Escherichia coli using photoluminescence (PL) emission from III–V quantum semiconductor (QS) devices functionalized with two different antibody-based architectures. The first approach employed self-assembled monolayers of biotinylated polyethylene glycol thiols to immobilize biotinylated antibody via neutravidin. In the second approach, we used QS microstructures coated with a thin layer of Si₃N₄ allowing direct functionalization with E. coli antibodies through hydrofluoric acid etching and glutaraldehyde-based reticulation. Atomic force, optical and fluorescence microscopy measurements were used to assess the immobilization process. Depending on the biosensing architecture, density of the immobilized bacteria was observed in the range of 0.5–0.7 bacteria/100 μm². The detection of E. coli at 10⁴ CFU/ml was achieved within less than 120 min of the bacteria exposure. It is expected that an even better sensitivity threshold could be achieved following further optimization of the method.     

A wireless sensor system for validation of real-time automatic calibration of groundwater transport models

In this paper, we present the use of a wireless sensor network in a lab for subsurface contaminant plume monitoring with the objective of automatic calibration of groundwater transport models. A tank configured to simulate an aquifer was used as a testbed, and a 2D model was created based on the setup. To simulate a contaminant plume, an ion tracer was injected into the tank. Sensor probes capable of detecting the plume were buried inside the tank, and wireless motes used to take readings from the sensors and relay data to a base station. More importantly, a run-time fault detection and diagnosis for abnormal sensor readings is designed and integrated into the data acquisition system. Further, an adaptive data collection technique is integrated that is able to provide evidence about the effectiveness of the groundwater transport model in use. Results from the tracer tests are presented, as well as lessons gained.     

A framework for use of wireless sensor networks in forest fire detection and monitoring

Forest fires are one of the main causes of environmental degradation nowadays. Current surveillance systems for forest fires lack in supporting real-time monitoring of every point of a region at all times and early detection of fire threats. Solutions using wireless sensor networks, on the other hand, can gather sensory data values, such as temperature and humidity, from all points of a field continuously, day and night, and, provide fresh and accurate data to the fire-fighting center quickly. However, sensor networks face serious obstacles like limited energy resources and high vulnerability to harsh environmental conditions, that have to be considered carefully. In this paper, we propose a comprehensive framework for the use of wireless sensor networks for forest fire detection and monitoring. Our framework includes proposals for the wireless sensor network architecture, sensor deployment scheme, and clustering and communication protocols. The aim of the framework is to detect a fire threat as early as possible and yet consider the energy consumption of the sensor nodes and the environmental conditions that may affect the required activity level of the network. We implemented a simulator to validate and evaluate our proposed framework. Through extensive simulation experiments, we show that our framework can provide fast reaction to forest fires while also consuming energy efficiently.     

Detection of Escherichia coli using CMOS array photo sensor-based enzyme biochip detection system

This work presents optical enzyme detection system based on the CMOS array photo sensor and 1 × 3 polymeric enzyme biochip for detecting Escherichia coli in a one-step procedure. This assay, using 4-methylumbelliferyl-β-d-glucuronide (MUG) as a fluorogenic substrate, had a detection limit of 0.1 U/ml for β-glucuronidase (GUD), which was approximately equal to a cell concentration of 10⁶ CFU/ml of E. coli. MUG was incorporated into lauryl tryptose broth at a final concentration of 100 μg/ml for immediate verification of the presence of E. coli in 1 × 3 polymeric enzyme biochip. The 40 strains of E. coli studied all produced GUD. Of another 36 strains of bacteria tested, one strain (Salmonella choleraesuis subsp. choleraesuis) yielded very small amounts of GUD after 24 h incubation. The optical enzyme detection system was sensitive and rapid.     

A wireless magnetoelastic-sensing device for in situ evaluation of Pseudomonas aeruginosa biofilm formation

A wireless, passive magnetoelastic-sensing device is presented for the in situ, continuous, and real-time evaluation of the formation of Pseudomonas aeruginosa biofilms. The sensor, a polyurethane-coated magnetostrictive ribbon, is placed in a flowing system, and both the resonance frequency and amplitude of the sensor are wirelessly monitored through magnetic field telemetry. The sensor platform appears to be of great utility for the in situ evaluation of biofilms formation.     

CrimeSPOT: A language and runtime for developing active wireless sensor network applications

Advances in wireless sensing and actuation technology allow embedding significant amounts of application logic inside wireless sensor networks. Such active WSN applications are more autonomous, but are significantly more complex to implement. Event-based middleware lends itself to implementing these applications. It offers developers fine-grained control over how an individual node interacts with the other nodes of the network. However, this control comes at the cost of event handlers which lack composability and violate software engineering principles such as separation of concerns. In this paper, we present CrimeSPOT as a domain-specific language for programming WSN applications on top of event-driven middleware. Its node-centric features enable programming a node’s interactions through declarative rules rather than event handlers. Its network-centric features support reusing code within and among WSN applications. Unique to CrimeSPOT is its support for associating application-specific semantics with events that carry sensor readings. These preclude transposing existing approaches that address the shortcomings of event-based middleware to the domain of wireless sensor networks. We provide a comprehensive overview of the language and the implementation of its accompanying runtime. The latter comprises several extensions to the Rete forward chaining algorithm. We evaluate the expressiveness of the language and the overhead of its runtime using small, but representative active WSN applications.     

检测大肠杆菌O157:H7的电化学阻抗谱生物传感器的研究

我们提出了用掺锡的三氧化二铟(ITO)作为工作电极,通过硅烷化固定化技术,将抗大肠杆菌O157:H7单克隆抗体固定在ITO电极表面,利用电化学阻抗谱技术来构建一种新型的免疫传感器.该新型的免疫传感器的检测限为 4×103CFU/mL,检测线性范围为4×103-4×106CFU/mL.实验研究表明,该传感器具有灵敏度较高,检测时间短,操作简单等优点,在临床医学和环境监测中具有应用价值.     

On the anonymity of two-factor authentication schemes for wireless sensor networks: Attacks,principle and solutions

Anonymity is among the important properties of two-factor authentication schemes for wireless sensor networks (WSNs) to preserve user privacy. Though impressive efforts have been devoted to designing schemes with user anonymity by only using lightweight symmetric-key primitives such as hash functions and block ciphers, to the best of our knowledge none has succeeded so far. In this work, we take an initial step to shed light on the rationale underlying this prominent issue. Firstly, we scrutinize two previously-thought sound schemes, namely Fan et al.’s scheme and Xue et al.’s scheme, and demonstrate the major challenges in designing a scheme with user anonymity.Secondly, using these two foremost schemes as case studies and on the basis of the work of Halevi–Krawczyk (1999) [44] and Impagliazzo–Rudich (1989) [43], we put forward a general principle: Public-key techniques are intrinsically indispensable to construct a two-factor authentication scheme that can support user anonymity. Furthermore, we discuss the practical solutions to realize user anonymity. Remarkably, our principle can be applied to two-factor schemes for universal environments besides WSNs, such as the Internet, global mobility networks and mobile clouds. We believe that our work contributes to a better understanding of the inherent complexity in achieving user privacy, and will establish a groundwork for developing more secure and efficient privacy-preserving two-factor authentication schemes.     

CMAC, CCM and GCM/GMAC: Advanced modes of operation of symmetric block ciphers in wireless sensor networks

Symmetric block ciphers are usually used in WSN for security services. This paper puts forward the idea of using advanced modes of operation of symmetric block ciphers to achieve confidentiality and authentication in one cryptographic operation. The modes of operation approved by NIST that is CMAC, CCM, GCM/GMAC are applied here. The benchmarks of these approaches in the terms of efficiency of nodes in WSN are presented.     

A PDMS microfluidic impedance immunosensor for E. coli O157:H7 and Staphylococcus aureus detection via antibody-immobilized nanoporous membrane

In this article, a PDMS microfluidic immunosensor integrated with specific antibody immobilized alumina nanoporous membrane was developed for rapid detection of foodborne pathogens Escherichia coli O157:H7 and Staphylococcus aureus with electrochemical impedance spectrum. Firstly, antibodies to the targeted bacteria were covalently immobilized on the nanoporous alumina membranes via self assembled (3-glycidoxypropyl)trimethoxysilane (GPMS) silane. Then, the impedance spectrum was recorded for bacteria detection ranging from 1 Hz to 100 kHz. The maximum impedance amplitude change for these two food pathogens was around 100 Hz. This microfluidic immunosensor based on nanoporous membrane impedance spectrum could achieve rapid bacteria detection within 2 h with a high sensitivity of 10² CFU/ml. Cross-bacteria experiments for E. coli O157:H7 and S. aureus were also explored to testify the specificity. The results showed that impedance amplitude at 100 Hz had a significant reduction in binding of bacteria when the membrane was exposed to non-specific bacteria.