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  • 1
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    Energy-efficient chain-based data gathering applied to communicating concrete (2020)
    Sage Publications
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    Publikationsdatum: 2020-08-01
    Beschreibung: Wireless Sensor Networks are very convenient to monitor structures or even materials, as in McBIM project (Materials communicating with the Building Information Modeling). This project aims to develop the concept of “communicating concretes,” which are concrete elements embedding wireless sensor networks, for applications dedicated to Structure Health Monitoring in the construction industry. Due to applicative constraints, the topology of the wireless sensor network follows a chain-based structure. Node batteries cannot be replaced or easily recharged, it is crucial to evaluate the energy consumed by each node during the monitoring process. This area has been extensively studied leading to different energy models to evaluate energy consumption for chain-based structures. However, no simple, practical, and analytical network energy models have yet been proposed. Energy evaluation models of periodic data collection for chain-based structures are proposed. These models are compared and evaluated with an Arduino XBee–based platform. Experimental results show the mean prediction error of our models is 5%. Realizing aggregation at nodes significantly reduces energy consumption and avoids hot-spot problem with homogeneous consumptions along the chain. Models give an approximate lifetime of the wireless sensor network and communicating concretes services. They can also be used online by nodes for a self-assessment of their energy consumptions.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
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  • 2
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    Performance Analysis of Ti-Doped In2O3 Thin Films Prepared by Various Doping Concentrations Using RF Magnetron Sputtering for Light-Emitting Device (2020)
    Hindawi
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    Publikationsdatum: 2020-08-28
    Beschreibung: The influences of doping amounts of TiO2 on the structure and electrical properties of In2O3 films were experimentally studied. In this study, titanium-doped indium oxide (ITiO) conductions were deposited on glass substrate by the dual-target-type radio frequency magnetron sputtering (RFS) system under different conditions of Ti-doped In2O3 targets, from Ti-0.5 wt% to Ti-5.0 wt%, along with 10 mTorr and 300 W pressure of RF power control that was used as a cost-effective transparent electrochemiluminescence (ECL) cell. From this process, the correlation between structural, optical, and electrical properties is reported. It was found that the best 1.14×10−4 Ω cm of resistivity was from Ti-2.5 wt% with the highest carrier concentration (1.15 × 1021 cm-3), Hall mobility (46.03 cm2/V·s), relatively transmittance (82%), and ECL efficiency (0.43 lm·W-1) with well crystalline structured and smooth morphology. As a result, researchers can be responsible for preparing ITiO thin films with significantly improved microstructure and light intensity performance for the effectiveness of the display devices, as well as its simple process and high performance.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Energietechnik
    Publiziert von Hindawi
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  • 3
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    Experimental investigation of concrete strength curve based on pull-out post-insert method (2020)
    Sage Publications
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    Publikationsdatum: 2020-07-01
    Beschreibung: As concrete is a building material that is widely used in the field of infrastructure construction, and its quality is related to the quality and service life in infrastructure engineering, concrete strength is an important reference index that reflects the concrete quality. Based on this, two commercial concretes A and B are selected in Henan Province, China, to perform the concrete strength test under same condition curing and standard condition curing in the pull-out post-insert method, cubic compression, rebound method, and drilling core method. The relationships between the different curing conditions, cubic compressive strength, core sample strength, rebound strength, and pull-out force of different commercial concretes are compared and analyzed. Through a comparative analysis and while considering the convenience and accuracy requirements, the strength curves of the two different concretes based on the pull-out post-insert method were fitted and analyzed, and the local strength curve test in Henan based on the pull-out post-insert method was established. The research results provide technical support for evaluating the strength of concrete structures using the pull-out post-insert method, which has important engineering significance for improving the popularize and application of the pull-out post-insert method.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
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  • 4
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    New Design of Solar Photovoltaic and Thermal Hybrid System for Performance Improvement of Solar Photovoltaic (2020)
    Hindawi
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    Publikationsdatum: 2020-07-15
    Beschreibung: Solar photovoltaic (PV) and solar thermal systems are most widely used renewable energy technologies. Theoretical study indicates that the energy conversion efficiency of solar photovoltaic gets reduced about 0.3% when its temperature increases by 1°C. In this regard, solar PV and thermal (PVT) hybrid systems could be a solution to draw extra heat from the solar PV panel to improve its performance by reducing its temperature. Here, we have designed a new type of heat exchanger for solar PV and thermal (PVT) hybrid systems and have studied the performance of the system. The PVT system has been investigated in comparison with an identical solar PV panel at outdoor condition at Dhaka, Bangladesh. The experiments show that the average improvement of open circuit voltage (Voc) is 0.97 V and the highest improvement of Voc is 1.3 V. In addition, the overall improvement of output power of solar PV panel is 2.5 W.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Energietechnik
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  • 5
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    Jointly designed quasi-cyclic LDPC-coded cooperation with diversity combining at receiver (2020)
    Sage Publications
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    Publikationsdatum: 2020-07-01
    Beschreibung: This correspondence proposes a jointly-designed quasi-cyclic (QC) low-density parity-check (LDPC)-coded multi-relay cooperation with a destination node realized by multiple receive antennas. First, a deterministic approach is utilized to construct different classes of binary QC-LDPC codes with no length-4 cycles. Existing methods put some limitations in terms of code length and rate in order to provide high error-correction performance. Therefore, this article gives three classes of QC-LDPC codes based on a combinatoric design approach, known as cyclic difference packing (CDP), with flexibility in terms of code-length and rate selection. Second, the proposed CDP-based construction is utilized to jointly-design QC-LDPC codes for coded-relay cooperation. At the receiver, the destination node is realized by multiple receive antennas, where maximal-ratio combining (MRC) and sum-product algorithm (SPA)-based joint iterative decoding are utilized to decode the corrupted sequences coming from the source and relay nodes. Simulation results show that the proposed QC-LDPC coded-relay cooperations outperform their counterparts with a coding gain of about 0.25 dB at bit-error rate (BER) [Formula: see text] over a Rayleigh fading channel in the presence of additive white Gaussian noise. Furthermore, the extrinsic-information transfer (EXIT) chart analysis has been used to detect the convergence threshold of proposed jointly-designed QC-LDPC codes. Numerical analysis shows that the proposed jointly-designed QC-LDPC codes provide a better convergence as compared to their counterparts under the same conditions.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
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  • 6
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    Photovoltaic Module with Uniform Water Flow on Top Surface (2020)
    Hindawi
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    Publikationsdatum: 2020-07-10
    Beschreibung: Though the solar photovoltaic (PV) module is used for power production, it usually works at high temperatures, decreasing its efficiency and therefore its output. So if an effective cooling method is to be implemented, it would reduce the heat from the solar PV module and increase its power production. Significant research in water cooling on both top and bottom surfaces of the PV module widen the scope for uniform cooling with constant module temperature throughout at any instant. In this work, uniform flow is maintained by means of overflow water from a tank fitted on the top of the PV module. Experiments were carried out with and without cooling. Performance parameters in terms of power output and efficiency have been presented for the PV module without cooling and cooling with three different mass flow rates. The results show that there is a significant rise in efficiency of the PV module by reducing its temperature. An accelerated output power of 23 W has been observed for a higher mass flow rate of 5.3 kg/min which is 15% higher than the photovoltaic module operating without cooling. Results were compared with previous researchers’ work and found to be a good enhancement. Theoretical results agree well with experiments.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Energietechnik
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  • 7
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    A hybrid dual-mode trust management scheme for vehicular networks (2020)
    Sage Publications
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    Publikationsdatum: 2020-07-01
    Beschreibung: Vehicular ad-hoc networks allow vehicles to exchange messages pertaining to safety and road efficiency. Building trust between nodes can, therefore, protect vehicular ad-hoc networks from malicious nodes and eliminate fake messages. Although there are several trust models already exist, many schemes suffer from varied limitations. For example, many schemes rely on information provided by other peers or central authorities, for example, roadside units and reputation management centers to ensure message reliability and build nodes’ reputation. Also, none of the proposed schemes operate in different environments, for example, urban and rural. To overcome these limitations, we propose a novel trust management scheme for self-organized vehicular ad-hoc networks. The scheme is based on a crediting technique and does not rely on other peers or central authorities which distinguishes it as an economical solution. Moreover, it is hybrid, in the sense it is data-based and entity-based which makes it capable of revoking malicious nodes and discarding fake messages. Furthermore, it operates in a dual-mode (urban and rural). The simulation has been performed utilizing Veins, an open-source framework along with OMNeT++, a network simulator, and SUMO, a traffic simulator. The scheme has been tested with two trust models (urban and rural). The simulation results prove the performance and security efficacy of the proposed scheme.
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  • 8
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    Mobile target localization based on iterative tracing for underwater wireless sensor networks (2020)
    Sage Publications
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    Publikationsdatum: 2020-07-01
    Beschreibung: In underwater wireless sensor networks, sensor position information has important value in network protocols and collaborative detection. However, many challenges were introduced in positioning sensor nodes due to the complexity of the underwater environment. Aiming at the problem of the stratification effect of underwater acoustic waves, the long propagation delay of messages, as well as the mobility of sensor nodes, a mobile target localization scheme for underwater wireless sensor network is proposed based on iterative tracing. Four modules are established in the mobile target localization based on iterative tracing: the data collection and rough position estimation, the estimation and compensation of propagation delay, the node localization, and the iteration. The deviation of distance estimation due to the assumption that acoustic waves propagate along straight lines in an underwater environment is compensated by the mobile target localization based on iterative tracing, and weighted least squares estimation method is used to perform linear regression. Moreover, an interacting multiple model algorithm is put forward to reduce the positioning error caused by the mobility of sensor nodes, and the two services of node time synchronization and localization assist each other during the iteration to improve the accuracy of both parties. The simulation results show that the proposed scheme can achieve higher localization accuracy than the similar schemes, and the positioning errors caused by the above three problems can be reduced effectively.
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  • 9
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    Oxygen Vacancy-Mediated Interfacial Charge Transfer of Au/ZnO Schottky Heterojunctions for Enhanced UV Photodegradation (2020)
    Hindawi
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    Publikationsdatum: 2020-07-07
    Beschreibung: We intend to report an interesting phenomenon related to the different interfacial transfer processes between ellipsoidal-like ZnO (E-ZnO) and rod-like ZnO (R-ZnO) nanoheterojunctions witness by the nanosecond time-resolved transient photoluminescence (NTRT-PL) spectra. Fristly, E-ZnO and R-ZnO nanoarchitectures were fabricated via facilitating the electrochemical route; and then, they decorated it with dispersed Au nanoparticles (NPs) by the methods of ion-sputtering deposition, constituting Au/E-ZnO and Au/R-ZnO Schottky-heterojunction nanocomplex, which is characterized by SEM, XRD, Raman analysis, and UV-vis absorption spectra. Steady-state photoluminescence and NTRT-PL spectra of as-fabricated Au/E-ZnO and Au/R-ZnO nanocomposites were probed for interfacial charge transfer process under 266 nm femtosecond (fs) light irradiation. Simultaneously, a distinct diversification for the NTRT-PL spectra is observed, closely associating with oxygen vacancies (Vo), which is confirmed by X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) spectra. Furthermore, Au NPs act as an “annular bridge” and “transit depot” for interfacial charge transfer through local surface plasmon resonance (LSPR) effect and Schottky barrier, respectively, which is identified by NTRT-PL and time-resolved PL (TRPL) decay spectrum. Moreover, this mechanism is responsible for the enhanced photoelectrochemical (PEC) performances of methyl orange (MO) photodegradation under UV light irradiation.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Energietechnik
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  • 10
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    Distributed Fault-Tolerant Event Region Detection of Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-09-10
    Beschreibung: This work provides a distributed fault-tolerant event region detection algorithm for wireless sensor networks. The proposed algorithm can identify faulty and fault-free sensors and ignore the abnormal readings to avoid false alarm. Moreover, every event region can also be detected and identified. Simulation results show that fault detection accuracy (FDA) is greater than 92%, false alarm rate (FAR) is near 0%, and event detection accuracy (EDA) is greater than 99% under uniform distribution. FDA is greater than 92%, FAR is less than 1.2%, and EDA is greater than 88% under random distribution when sensor fault probability is less than 0.3.
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  • 11
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    Numerical Analysis of Copper-Indium-Gallium-Diselenide-Based Solar Cells by SCAPS-1D (2013)
    Hindawi
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    Publikationsdatum: 2013-09-11
    Beschreibung: We used a one-dimensional simulation program Solar Cell Capacitance Simulator in 1 Dimension (SCAPS-1D) to investigate Copper-Indium-Gallium-Diselenide- (CIGS-) based solar cells properties. Starting with a conventional ZnO-B/i-ZnO/CdS/CIGS structure, we simulated the parameters of current-voltage characteristics and showed how the absorber layer thickness, hole density, and band gap influence the short-circuit current density (), open-circuit voltage (), fill factor (FF), and efficiency of solar cell. Our simulation results showed that all electrical parameters are greatly affected by the absorber thickness (w) below 1000 nm, due to the increase of back-contact recombination and very poor absorption. Increasing hole density (p) or absorber band gap () improves and leads to high efficiency, which equals value of 16.1% when p = 1016 cm−3 and  eV. In order to reduce back-contact recombination, the effect of a very thin layer with high band gap inserted near the back contact and acting as electrons reflector, the so-called back-electron reflector (EBR), has been investigated. The performances of the solar cells are significantly improved, when ultrathin absorbers (w 〈 500 nm) are used; the corresponding gain of due to the EBR is 3 mA/cm2. Our results are in good agreement with those reported in the literature from experiments.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Energietechnik
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  • 12
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    Solar Power Generation (2013)
    Hindawi
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    Publikationsdatum: 2013-09-11
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Energietechnik
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  • 13
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    Effect of UV Irradiation on Interactions of -Lipoic Acid with Free Radicals (2013)
    Hindawi
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    Publikationsdatum: 2013-09-12
    Beschreibung: Changes of antioxidant properties of -lipoic acid (LA) after UV irradiation were studied. LA is the typical drug used in diabetic neuropathy. Quenching of free radicals is an important factor of therapy by using this substance. -Lipoic acid is exposed to UV irradiation during the storage. The aim of our studies was to examine the effect of UV irradiation on the interactions of LA with free radicals. The -lipoic acid was irradiated by UVA 315–400 nm light during 10 to 110 minutes by intervals of 10 minutes. The electron paramagnetic resonance spectroscopy was used as the experimental technique. The antioxidant properties of LA were spectroscopically confirmed. The strong effect of UV irradiation on interactions of -lipoic acid with free radicals was observed. It was pointed out that interactions of LA with free radicals decrease after its exposition on UV. The interactions of LA with free radicals were higher after the sample irradiation during 10 minutes than for the samples irradiated longer (20–110 minutes). The results are important for problems connected with photomedicine; they pointed out that -lipoic acid should not be stored on UV exposition. Application of electron paramagnetic resonance spectroscopy to characterize interactions of pharmacological substance with free radicals was confirmed.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Energietechnik
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  • 14
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    Enhanced Photoelectrochemical Response from Copper Antimony Zinc Sulfide Thin Films on Transparent Conducting Electrode (2013)
    Hindawi
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    Publikationsdatum: 2013-09-12
    Beschreibung: Copper antimony sulfide (CAS) is a relatively new class of sustainable absorber material, utilizing cost effective and abundant elements. Band gap engineered, modified CAS thin films were synthesized using electrodeposition and elevated temperature sulfurization approach. A testing analog of copper zinc antimony sulfide (CZAS) film-electrolyte interface was created in order to evaluate photoelectrochemical performance of the thin film of absorber materials. Eu3+/Eu2+ redox couple was selected for this purpose, based on its relative band offset with copper antimony sulfide. It was observed that zinc has a significant effect on CAS film properties. An enhanced photocurrent was observed for CAS film, modified with zinc addition. A detailed investigation has been carried out by changing stoichiometry, and corresponding surface and optical characterization results have been evaluated. A summary of favorable processing parameters of the films showing enhanced photoelectrochemical response is presented.
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  • 15
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    - Calculations in CdS/CdTe Thin Films Solar Cells with a Interlayer (2013)
    Hindawi
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    Publikationsdatum: 2013-09-12
    Beschreibung: In CdS/CdTe solar cells, chemical interdiffusion at the interface gives rise to the formation of an interlayer of the ternary compound . In this work, we evaluate the effects of this interlayer in CdS/CdTe photovoltaic cells in order to improve theoretical results describing experimental - (capacitance versus voltage) characteristics. We extended our previous theoretical methodology developed on the basis of three cardinal equations (Castillo-Alvarado et al., 2010). The present results provide a better fit to experimental data obtained from CdS/CdTe solar cells grown in our laboratory by the chemical bath deposition (for CdS film) and the close-spaced vapor transport (for CdTe film) techniques.
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  • 16
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    A Quantitative Analysis of Photovoltaic Modules Using Halved Cells (2013)
    Hindawi
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    Publikationsdatum: 2013-09-12
    Beschreibung: In a silicon wafer-based photovoltaic (PV) module, significant power is lost due to current transport through the ribbons interconnecting neighbour cells. Using halved cells in PV modules is an effective method to reduce the resistive power loss which has already been applied by some major PV manufacturers (Mitsubishi, BP Solar) in their commercial available PV modules. As a consequence, quantitative analysis of PV modules using halved cells is needed. In this paper we investigate theoretically and experimentally the difference between modules made with halved and full-size solar cells. Theoretically, we find an improvement in fill factor of 1.8% absolute and output power of 90 mW for the halved cell minimodule. Experimentally, we find an improvement in fill factor of 1.3% absolute and output power of 60 mW for the halved cell module. Also, we investigate theoretically how this effect confers to the case of large-size modules. It is found that the performance increment of halved cell PV modules is even higher for high-efficiency solar cells. After that, the resistive loss of large-size modules with different interconnection schemes is analysed. Finally, factors influencing the performance and cost of industrial halved cell PV modules are discussed.
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  • 17
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    Research on the Comparison Analyses of Three-Phase Discrete and Integrated LC Filters in Three-Phase PV Inverter (2013)
    Hindawi
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    Publikationsdatum: 2013-09-12
    Beschreibung: In three-phase photovoltaic (PV) system, three-phase filter inductors are important part for the output electrical power quality. The comparison analyses of three-phase discrete filter inductors and two kinds of three-phase integrated filter inductors in three-phase PV inverter are proposed. Firstly, the three-phase PV inverter operation with discrete filter inductors is analyzed, and the design of discrete filter inductors is given; then operation of the three-phase PV inverter with three-phase integrated five-limb magnetic core filter inductors is analyzed, the design of integrated filter inductors with five-limb magnetic core is given, then the operation of three-phase PV inverter with three-phase integrated three-limb magnetic core filter inductors is analyzed, and the design of integrated filter inductors with three limbs magnetic core is given. The conclusion of comparison between three-phase discrete filter inductors and two kinds of three-phase integrated filter inductors is done; it means that the three-phase discrete filter inductors can achieve better output electrical power quality with lower power density and three-phase integrated filter inductors can achieve higher power density with lower output electrical power quality. Finally, the experiment results are given to compare the volume and filter effect of three kinds of filter inductors in three-phase PV inverter.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Energietechnik
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  • 18
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    Field Measurement of Wind Effects of Roof Accessory Structures on Gable-Roofed Low-Rise Building (2013)
    Hindawi
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    Publikationsdatum: 2013-09-13
    Beschreibung: The components and claddings of low-rise buildings are usually destroyed first during typhoon disasters in coastal areas. Roof accessory structures can change the flow pattern on the roof, thus effectively reducing the wind load on the roof surface and the damage to the low-rise buildings. Three types of aerodynamic mitigation plates, that is, (1) 0.3 m high full-length roof-edge plate, (2) 0.3 m high and 0.5 m + 0.5 m long roof-corner plate, and (3) discrete roof-edge plates with different spaces (which can be used as advertisement boards), are studied on the basis of the field measurement results under roof pitches of 10° and 18.4°. By comparing the results of the roof with and without constructed plates, it is implied that the three types of plates can affect the formation of conical vortexes and can significantly reduce the mean and fluctuating pressure coefficients in the windward corner. Compared with the constructed plate, the roof ridge has a larger influence on the wind loads on leeward roof.
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  • 19
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    Effectively Improved SiO2-TiO2 Composite Films Applied in Commercial Multicrystalline Silicon Solar Cells (2013)
    Hindawi
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    Publikationsdatum: 2013-09-13
    Beschreibung: Composite silicon dioxide-titanium dioxide (SiO2-TiO2) films are deposited on a large area of 15.6 × 15.6 cm2 textured multicrystalline silicon solar cells to increase the incident light trapped within the device. For further improvement of the antireflective coatings (ARCs) quality, dimethylformamide (DMF) solution is added to the original SiO2-TiO2 solutions. DMF solution solves the cracking problem, thus effectively decreasing reflectance as well as surface recombination. The ARCs prepared by sol-gel process and plasma-enhanced chemical vapor deposition (PECVD) on multicrystalline silicon substrate are compared. The average efficiency of the devices with improved sol-gel ARCs is 16.3%, only 0.5% lower than that of devices with PECVD ARCs (16.8%). However, from equipment depreciation point of view (the expiration date of equipment is generally considered as 5 years), the running cost (USD/watt) of sol-gel technique is 80% lower than that of PECVD method for the first five years and 66% lower than that of PECVD method from the start of the sixth year. This result proves that sol-gel-deposited ARCs process has potential applications in manufacturing low-cost, large-area solar cells.
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    Throughput-Optimal Scheduling for Cooperative Communications in Wireless Ad Hoc Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-09-15
    Beschreibung: Cooperative communications that take advantage of the broadcasting nature of wireless environments can help to increase system throughput in wireless ad hoc networks. However, the promised throughput might be lost in presence of the error transmission and the interference caused by relay transmission in cooperative communication. In this paper, we introduced the relay selection schemes that can control the interference at the relay to prevent the relay that may harm other pairs. Then, we proposed the throughput-optimal scheduling that takes into account error probability in decision and maximizes throughput, that is, the amount of packets transmitted without error in network. In addition, we derive a simple and lightweight framework to implement the proposed policy in distributed manner. The simulation results show that the proposed scheduling policy outperforms the noncooperative policy and multihop relay policy.
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    A Novel PROMSIS Vertical Handoff Decision Algorithm for Heterogeneous Wireless Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-09-19
    Beschreibung: A novel preference ranking organization method by similarity to ideal solution (PROMSIS) vertical handoff algorithm is proposed for heterogeneous wireless networks, and its essential idea includes the preference structure of the PROMETHEE and the concept of Euclid distance of the TOPSIS. Four 3GPP defined traffic classes are considered in performance evaluation. An attribute matrix is constructed considering some major attributes. Handoff decision meeting multiattribute QoS requirement is made according to the traffic features. The weight relation of decision elements is determined with the least square (LS) approach. The final decision is made using the proposed PROMSIS algorithm based on the attribute matrix and weight vector. The simulation results have manifested that the proposed PROMSIS algorithm can provide satisfactory vertical handoff performance, and the LS-PROMSIS algorithm can be fit to the characteristics of the traffic.
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    Enhanced Solar Photoelectrochemical Conversion Efficiency of ZnO:Cu Electrodes for Water-Splitting Application (2013)
    Hindawi
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    Publikationsdatum: 2013-09-20
    Beschreibung: n-type ZnO:Cu photoanodes were fabricated by simple spray pyrolysis deposition technique. Influence of low concentration (range ~10−4–10−1%) of Cu doping in hexagonal ZnO lattice on its photoelectrochemical performance has been investigated. The doped photoanodes displayed 7-time enhanced conversion efficiencies with respect to their undoped counterpart, as estimated from the photocurrents generated under simulated solar radiation. This is the highest enhancement in the solar conversion efficiency reported so far for the Cu-doped ZnO. This performance is attributed to the red shift in the band gap of the Cu-doped films and is in accordance with the incident-photon-current-conversion efficiency (IPCE) measurements. Electrochemical studies reveal an n-type nature of these photoanodes. Thus, the study indicates a high potential of doped ZnO films for solar energy applications, in purview of the development of simple nanostructuring methodologies.
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    Ontology-Based Methodology for Managing Heterogeneous Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-09-22
    Beschreibung: With the growing interest in ubiquitous technologies recently, many studies have been conducted in order to manage wireless sensor network, which is the central component in ubiquitous environment. To manage a certain wireless sensor network, a variety of techniques can be applied and thereby the network can be managed. However, it is very complicated and time-consuming to incorporate and manage more than a heterogeneous wireless sensor network since each network has different data, meanings, and terms. Instead of conducting verification through examining the detailed technology or simulation in order to manage a variety of wireless sensor networks, we suggest a methodology which manages data coming from the various sensors mentioned above, a technique by which those data from various sensor networks are managed in each different network, and a methodology which manages sensor networks where management languages exist. This paper defined the network-related terminology using Protégé for the tools and definitions necessary for ontology-based methodology, thereby defined OWL and the related rules, and suggested a methodology for incorporated management. In addition, this study showed that the methodology presented in this study has expandability and it can incorporate and manage a variety of wireless sensor networks.
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    A Framework for Robust Address Assignment in WSNs Whispering to Avoid Intruders (2013)
    Hindawi
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    Publikationsdatum: 2013-09-26
    Beschreibung: Wireless sensor networks (WSNs) are becoming bigger, and with this growth comes the need for new automatic mechanisms for initializations done by hand. One of those mechanisms is the assignment of addresses to nodes. Several solutions were already proposed for mobile ad hoc networks but they either (i) do not scale well for WSN; (ii) have no energy constraints; (iii) have no security considerations; (iv) or have no mechanisms to handle fusion of network partitions. We proposed an address self-assignment protocol which uses negative acknowledgements and an improved version of a flood control mechanism to minimize the energy spent; uses a technique named whispering to achieve robustness against malicious nodes; is able to detect dynamic network re-joint and dynamic node addition without exchanging specific messages; and handles both dynamic events without compromising routing tables.
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    Hardware Design of Seismic Sensors in Wireless Sensor Network (2013)
    Hindawi
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    Publikationsdatum: 2013-09-27
    Beschreibung: Seismic sensors are invaluable for intruder detection and perimeter security. In a typical wireless sensor network application of seismic sensors, the units are battery powered and low power consumption becomes critical while fulfilling system requirements. Although many systems utilize 24-bit ADC for seismic signal processing, we employed 12-bit ADC for low power consumption. Because of this relatively low resolution ADC, preamplifier and filters require careful hardware design. We employ bidirectional T-type filtering, noise reduction, and distributed filtering between gain stages before the signal is input to ADC. The proposed design was verified with measurements. Seismic data signals due to footsteps at varying distances were successfully measured.
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    Robust Detection of Malicious Nodes in Mobile Sensor Networks Using Software Attestation (2013)
    Hindawi
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    Publikationsdatum: 2013-09-27
    Beschreibung: In ad hoc and sensor networks, reputation-based trust management schemes have been widely used to identify the malicious nodes. These schemes leverage each node’s behaviors for malicious node detection and thus require a certain amount of time to observe the behaviors of nodes. In mobile sensor networks, however, malicious nodes frequently move to different locations, and thus it is likely difficult to collect enough evidence for them. Moreover, when reputation-based schemes are employed, it is not easy to revoke the malicious nodes due to the risk of false positives. To mitigate these limitations of reputation-based schemes, we propose mobile malicious node detection schemes based on software attestation technique, which virtually fulfills zero false positives. In particular, we propose a probabilistic detection scheme in which each node attests its neighboring node with a certain probability. In order to reduce the attestation overhead of the probabilistic detection scheme, we also propose the SPRT (Sequential Probability Ratio Test) based detection scheme that uses the SPRT to determine when to perform the attestations. Through analysis and simulation, we show that our proposed schemes detect mobile malicious nodes through software attestations in robust and efficient manner.
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    Hybrid Ant Algorithm Based Query Processing with Multiagents in Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-10-01
    Beschreibung: The wireless sensor networks are usually deployed in various application-specific contexts, which can be treated as distributed databases with big data. The event-involved query responses can be obtained by issuing query requests to this kind of database. However, the constraints of the energy and delay have had a great impact on the operation of wireless sensor networks. How to design the query-involved network model and the corresponding query processing algorithms is extremely challenging. This work investigates query processing problem in resource-constrained wireless sensor networks with the two-tier architecture and multiple query agents, where the multiple nodes of query agents are configured in the networks and the corresponding source cluster-heads send collected events to only one optimum query agent. To reduce the energy consumption and shorten the delivery delay, an efficient query processing algorithm inspired by the swarm intelligence of ants is proposed, which takes advantage of the beneficial clustering and routing emerging in a hybrid self-organized way from the positive interaction of ants. The experimental results demonstrated that the proposed algorithm can deliver collected events to the optimum query agents efficiently. Not only is the energy cost reduced but also the delivery delay is shortened significantly when transmitting the named events to the appropriate query agents.
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    The Nonuniform Node Configuration of Wireless Sensor Networks for Long-Span Bridge Health Monitoring (2013)
    Hindawi
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    Publikationsdatum: 2013-10-01
    Beschreibung: This paper presents a nonuniform node configuration of wireless sensor networks (WSNs) for long-span bridge health monitoring. The methodology and strategy of two-phase node arrangement for nonuniform WSN configuration are firstly presented, and then numerical examples are carried out by a long-span suspension bridge. Three cases, which are four sensor nodes distributed on one side of the girder, ten sensor nodes distributed on one side of the girder, and eight sensor nodes distributed averagely on two sides of the girder, are employed. In case I and case II, three schemes that are the nonuniform node configuration arranged by the two-phase node arrangement method, the uniform nodes configuration, and the independent sensor nodes configuration are used for comparison. And in case III, two schemes that are nonuniform nodes configuration and the independent sensor nodes configuration are adopted. The results indicate that the nonuniform node configuration can balance energy consumption, eliminate “energy hole,” and maximize network performance effectively, which shows the most outstanding performance when compared with other conventional node configurations. So, the efficiency of the two-phase node arrangement method is validated.
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    Photovoltaic System Modeling with Fuzzy Logic Based Maximum Power Point Tracking Algorithm (2013)
    Hindawi
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    Publikationsdatum: 2013-10-01
    Beschreibung: This paper represents a novel modeling technique of PV module with a fuzzy logic based MPPT algorithm and boost converter in Simulink environment. The prime contributions of this work are simplification of PV modeling technique and implementation of fuzzy based MPPT system to track maximum power efficiently. The main highlighted points of this paper are to demonstrate the precise control of the duty cycle with respect to various atmospheric conditions, illustration of PV characteristic curves, and operation analysis of the converter. The proposed system has been applied for three different PV modules SOLKAR 36 W, BP MSX 60 W, and KC85T 87 W. Finally the resultant data has been compared with the theoretical prediction and company specified value to ensure the validity of the system.
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    Spectrum Sensing for Cognitive Coexistent Heterogeneous Networks (2013)
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    Publikationsdatum: 2013-10-02
    Beschreibung: This paper proposes a noncoherent spectrum sensing scheme for the cognitive coexistent heterogeneous networks with the assistance of geolocation information of primary and secondary nodes. Different from the conventional networks with single secondary network, the spectrum sensing scheme in the coexistence scenario should not only detect the primary signal but also detect the secondary signals to avoid the interference with both the primary network and the operating coexistent secondary networks. Therefore, the sensing scheme in this case should be able to differentiate the primary signal from each kind of the secondary signals. However, in the coexistent heterogeneous scenarios, the secondary signals may exploit different PHY modes (some of them may be the same as the primary PHY mode), which imposes difficulties in the coherent signal detection schemes. Aiming to tackle this problem, the parallel detection of both primary signal and each kind of secondary signals is implemented through a proposed noncoherent power decomposition scheme. In this scheme, the power decomposition is formulated into a problem of solving a nonhomogeneous linear equation matrix. During the signal detection, the characteristics of both primary and secondary signals are not required. Both the analysis and the simulation results show the feasibility and efficiency of the proposed scheme.
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    A Smart Electronic Tagging System Based on Context Awareness and Machine-to-Machine Interworking (2013)
    Hindawi
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    Publikationsdatum: 2013-10-02
    Beschreibung: The existing electronic tagging system traces the location of a sex offender using triangulation by communicating with Global Positioning System (GPS) satellites and mobile phone base stations. The acquired location information is used to prevent the offenders from perpetrating repeat crimes. However, the battery resources of such a system are inadequate as it has to trace the location of the moving target in real time and consumes a large amount of battery power while communicating with GPS satellites and mobile phone base stations. In addition, the systems cannot infer the mental state of the targets or detect their alcohol consumption levels, which may be necessary for the prevention of a repeat crime. The purpose of this study is to connect the Ubiquitous System Network (USN), which consumes little electricity, and Android mobile platforms, which are commonly used for machine-to-machine communication. Thus, this system will legally facilitate the protection of minors by providing information only about the target’s approach to certain facilities. In addition, the system uses an Android platform to process data measured by the USN’s sensors, which can also detect alcohol intake and infer the mental state of the target, and then initiates the corresponding real-time context-awareness services.
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    Reconfigurable Antenna Assisted Intrusion Detection in Wireless Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-10-03
    Beschreibung: Intrusion detection is a challenging problem in wireless networks due to the broadcast nature of the wireless medium. Physical layer information is increasingly used to protect these vulnerable networks. Meanwhile, reconfigurable antennas are gradually finding their way into wireless devices due to their ability to improve data throughput. In this paper, the capabilities of reconfigurable antennas are used to devise an intrusion detection scheme that operates at the physical layer. The detection problem is posed as a GLRT problem that operates on the channels corresponding to the different modes of a reconfigurable antenna. The performance of the scheme is quantified through field measurements taken in an indoor environment at the 802.11 frequency band. Based on the measured data, we study the achievable performance and the effect of the different control parameters on the performance of the intrusion detection scheme. The effect of pattern correlation between the different modes on the scheme’s performance is also analyzed, based on which general guidelines on how to design the different antenna modes are provided. The results show that the proposed scheme can add an additional layer of security that can significantly alleviate many vulnerabilities and threats in current fixed wireless networks.
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    Joint Relay Ordering and Linear Finite Field Network Coding for Multiple-Source Multiple-Relay Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-10-03
    Beschreibung: Network coding (NC) is significant for the spectral efficiency promotion of the multiple-source multiple-relay wireless sensor networks (WSNs). However, the existing scheme ignored further exploitation of the communications between relays. To address this issue, a relay ordering algorithm based on finite field NC (FFNC) is proposed in this paper. In the scheme, the relays who initially fail to decode from sources are kept listening and searching for the opportunity to decode the signals from other relays, so as to recover the failure links. The outage probability of the scheme and the corresponding lower bound are theoretically deduced under two-source two-relay assumption. Moreover, the scheme is proved to own the merit of diffusion effect, which makes the diversity improvement more efficient by simply increasing the relay number in the network. Simulation results correspond well with the analysis and demonstrate that the proposed scheme always outperforms FFNC in outage behavior and attains more opportunities to supply full diversity for the network. Moreover, it shows that the diffusion effect enables this scheme to be very suitable for the multiple-relay WSN.
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    Preparation and Characterization of Chitosan Binder-Based Electrode for Dye-Sensitized Solar Cells (2013)
    Hindawi
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    Publikationsdatum: 2013-10-03
    Beschreibung: A chitosan binder-based TiO2 photoelectrode is used in dye-sensitized solar cells (DSSCs). Field-emission scanning electron microscope (FE-SEM) images revealed that the grain size, thickness, and distribution of TiO2 films are affected by the chitosan content. With addition of 2.0 wt% chitosan to the TiO2 film (D2), the surface pore size became the smallest, and the pores were fairly evenly distributed. The electron transit time, electron recombination lifetime, diffusion coefficient, and diffusion length were analyzed by IMVS and IMPS. The best DSSC, with 2.0 wt% chitosan addition to the TiO2 film, had a shorter electron transit time, longer electron recombination lifetime, and larger diffusion coefficient and diffusion length than the other samples. The results of 2.0 wt% chitosan-added TiO2 DSSCs are an electron transit time of  s, electron recombination lifetime of  s, diffusion coefficient of  cm2 s−1, diffusion length of 14.81 μm, and a solar conversion efficiency of 4.18%.
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    Synthesis of Nitrogen-Doped ZnS with Camellia Brushfield Yellow Nanostructures for Enhanced Photocatalytic Activity under Visible Light Irradiation (2013)
    Hindawi
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    Publikationsdatum: 2013-10-03
    Beschreibung: Nitrogen modified zinc sulfide photocatalysts were successfully prepared and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and surface area analysis. Thermal decomposition of the semisolid was carried out under nitrogen conditions at 500°C for 2 hours, and a series of nitrogen-doped ZnS photocatalysts were produced by controlling inflow flow rate of nitrogen at 15–140 mL/min. Optical characterizations of the synthesized N-doping ZnS substantially show the shifted photoabsorption properties from ultraviolet (UV) region to visible light. The band gaps of nitrogen-doped ZnS composite catalysts were calculated to be in the range of 2.58~2.74 eV from the absorptions edge position. The 15N/ZnS catalyst shows the highest photocatalytic activity, which results in 75.7% degradation of Orange II dye in 5 hrs by visible light irradiation, compared with pristine ZnS and higher percentage N-doping ZnS photocatalysts.
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    A Faster Convergence Artificial Bee Colony Algorithm in Sensor Deployment for Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-10-04
    Beschreibung: In wireless sensor networks (WSN), sensor deployment is one of the main topics for enhancing the sensor’s coverage rate. In this paper, by modifying updating equation of onlooker bee and scout bee of original artificial bee colony (ABC) algorithm, a sensor deployment algorithm based on the modified ABC algorithm is proposed. Some new parameters such as forgetting and neighbor factor for accelerating the convergence speed and probability of mutant for maximizing the coverage rate are introduced. Simulation results showed that comparing with the deployment method based on original ABC and particle swarm optimization (PSO) algorithm, the proposed approach can achieve a better performance in coverage rate and convergence speed while needing a less total moving distance of sensors.
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    Localization in Wireless Sensor Network (2013)
    Hindawi
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    Publikationsdatum: 2013-10-04
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    An Efficient WSN Simulator for GPU-Based Node Performance (2013)
    Hindawi
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    Publikationsdatum: 2013-10-04
    Beschreibung: In wireless sensor network, when these sensors are wrongly placed in an observation region, they can quickly run out of batteries or be disconnected. These incidents may result in huge losses in terms of sensing data from numerous sensors and their costs. For this reason, a number of simulators have been developed as tools for effective design and verification before the actual arrangement of sensors. While a number of simulators have been developed, simulation results can be fairly limited and the execution speed can be markedly slow depending on the function of each simulator. In this regard, to improve the performance of existing simulators, this research aimed to develop a parallel calculation simulator for independent sensor (PCSIS) that enables users to selectively use the GPU mode and, based on this mode, enables parallel and independent operations by matching GPU with many cores in order to resolve the slowdown of the execution speed when numerous sensor nodes are used for simulations. The PCSIS supports the GPU mode in an environment that allows the operation of compute unified device architecture (CUDA) and performs the parallel simulation calculation of multiple sensors using the mode within a short period of time.
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    Development of the Prediction System of Condensation Based on Wireless Communications (2013)
    Hindawi
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    Publikationsdatum: 2013-09-12
    Beschreibung: Due to advances in microelectromechanical system (MEMS), many smart sensors have been developed. A large number of sensors build a wireless sensor network and can communicate with each other. Wireless sensor networks help monitor objects in our environment, and many researches about this technology are in progress. Condensation is a phenomenon that water vapor contained in the air condenses and makes water droplets. This is caused by the complex action of a variety of factors, including the temperature difference between indoor and outdoor and excessive indoor moisture, so it is never easy to identify the cause and establish measures for the actual building. In this paper, a system is presented to predict and alert condensation promptly and accurately, considering the causes and prevention of condensation. In this paper, a system will be developed to collect and monitor environmental information causing condensation, in real time using a wireless sensor network in order to build a system to prevent condensation. The users are expected to use this system to easily identify the cause of condensation and take actions based on the cause-specific alarm messages in order to alleviate aesthetics and hygiene problems due to condensation.
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    DFT/TDDFT and Experimental Studies of Natural Pigments Extracted from Black Tea Waste for DSSC Application (2013)
    Hindawi
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    Publikationsdatum: 2013-09-12
    Beschreibung: We report results of combined experimental and theoretical studies of black tea waste extract (BTE) as a potential sensitizer for TiO2-dye-sensitized solar cells (DSSCs). UV-vis absorption data revealed that BTE contains theaflavin. DSSC sensitized with pigment complexes of BTE showed a photon-energy conversion efficiency of %, while a significant increase (%) is observed when pH of the pigment solution was lowered. The HOMO and LUMO energy levels were calculated using experimental data of UV-vis absorption and cyclic voltammetry. These calculations revealed a reduction of the band gap by 0.17 eV and more negativity of HOMO level of acidified pigment, compared to that of original pigment. Combined effect of these developments caused the enhanced efficiency of DSSC. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) computational calculations were carried out to study the four theaflavin analogues which are responsible for the dark colour of BTE. According to the calculations, two theaflavin analogues, theaflavin and theaflavin digallate, are the most probable sensitizers in this dye-sensitized solar cell system.
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    Coverage Optimization Algorithm Based on Sampling for 3D Underwater Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-09-13
    Beschreibung: We discuss the problem of maximizing the sensor field coverage for a specific number of sensors while minimizing the distance traveled by the sensor nodes. Thus, we define the movement task as an optimization problem that involves the adjustment of sensor node positions in a coverage optimization mission. We propose a coverage optimization algorithm based on sampling to enhance the coverage of 3D underwater sensor networks. The proposed coverage optimization algorithm is inspired by the simple random sampling in probability theory. The main objective of this study is to lessen computation complexity by dimension reduction, which is composed of two detailed steps. First, the coverage problem in 3D space is converted into a 2D plane for heterogeneous networks via sampling plane in the target 3D space. Second, the optimization in the 2D plane is converted into an optimization in a line segment by using the line sampling method in the sample plane. We establish a quadratic programming mathematical model to optimize the line segment coverage according to the intersection between sensing circles and line segments while minimizing the moving distance of the nodes. The intersection among sensors is decreased to increase the coverage rate, while the effective sensor positions are identified. Simulation results show the effectiveness of the proposed approach.
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    Exergy, Energy, and Dynamic Parameter Analysis of Indigenously Developed Low-Concentration Photovoltaic System (2013)
    Hindawi
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    Publikationsdatum: 2013-09-13
    Beschreibung: Piecewise linear parabolic trough collector (PLPTC) is designed and developed to concentrate solar radiation on monocrystalline silicon based photovoltaic module. A theoretical model is used to perform electrical energy and exergy analysis of low-concentration photovoltaic (LCPV) system working under actual test conditions (ATC). The exergy efficiency of LCPV system is in the range from 5.1% to 4.82% with increasing rate of input exergy rate from 30.81 W to 96.12 W, when concentration ratio changes from 1.85 to 5.17 Sun. Short-circuit current shows increasing trend with increasing input exergy rate of ≈0.011 A/W. Power conversion efficiency decreases from 7.07 to 5.66%, and open-circuit voltage decreases from 9.86 to 8.24 V with temperature coefficient of voltage  V/K under ATC. The results confirm that the commercially available silicon solar PV module performs satisfactorily under low concentration.
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    QoS-Aware Fault Detection in Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-09-13
    Beschreibung: Wireless sensor networks (WSNs) are a fundamental building block of many pervasive applications. Nevertheless the use of such technology raises new challenges regarding the development of reliable and fault-tolerant systems. One of the most critical issues is the detection of corrupted readings amidst the huge amount of gathered sensory data. Indeed, such readings could significantly affect the quality of service (QoS) of the WSN, and thus it is highly desirable to automatically discard them. This issue is usually addressed through “fault detection” algorithms that classify readings by exploiting temporal and spatial correlations. Generally, these algorithms do not take into account QoS requirements other than the classification accuracy. This paper proposes a fully distributed algorithm for detecting data faults, taking into account the response time besides the classification accuracy. We adopt the Bayesian networks to perform classification of readings and the Pareto optimization to allow QoS requirements to be simultaneously satisfied. Our approach has been tested on a synthetic dataset in order to evaluate its behavior with respect to different values of QoS constraints. The experimental evaluation produced good results, showing that our algorithm is able to greatly reduce the response time at the cost of a small reduction in classification accuracy.
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    Wireless Sensor Networks for the Internet of Things (2013)
    Hindawi
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    Publikationsdatum: 2013-09-17
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    Optical and Electrical Properties of Thin Films of CuS Nanodisks Ensembles Annealed in a Vacuum and Their Photocatalytic Activity (2013)
    Hindawi
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    Publikationsdatum: 2013-09-18
    Beschreibung: Effects on the optical, electrical, and photocatalytic properties of undoped CuS thin films nanodisks vacuum annealed at different temperatures were investigated. The chemical bath prepared CuS thin films were obtained at 40°C on glass substrates. The grain size of  nm was computed directly from high-resolution transmission electron microscopy (HRTEM) images. The electrical properties were measured by means of both Hall effect at room temperature and dark resistivity as a function of the absolute temperature 100–330 K. The activation energy values were calculated as 0.007, 0.013, and 0.013 eV for 100, 150, and 200°C, respectively. The energy band gap of the films varied in the range of 1.98 up to 2.34 eV. The photocatalytic activity of the CuS thin film was evaluated by employing the degradation of aqueous methylene blue solution in the presence of hydrogen peroxide. The CuS sample thin film annealed in vacuum at 150°C exhibited the highest photocatalytic activity in presence of hydrogen peroxide.
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    W-LEACH Based Dynamic Adaptive Data Aggregation Algorithm for Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-09-19
    Beschreibung: We consider the problem of data aggregation for nonuniform and evolving wireless sensor networks. We introduce a new data aggregation algorithm that is able to run on uniform, non-uniform, and evolving networks while maintaining the data accuracy. In addition, the algorithm is able to handle sudden bursts in the underlying data by recording the data in the area of interest for the whole event duration. Experimental results on real and synthetic data show that the algorithm performs well in terms of extending the lifetime of the network, maintaining the original distribution of the sensors as long as possible, maintaining the accuracy of the sensed data, and being able to detect and handle sudden bursts of data.
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    Congestion Control Based on Consensus in the Wireless Sensor Network (2013)
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    Publikationsdatum: 2013-09-19
    Beschreibung: The congestion control algorithm based on the weighted directed graph is designed for the network congestion over the wireless sensor network. The congestion problem is modeled as a distributed dynamic system with time-varying delay, and it can be proven that the sent rate for all nodes converges to the available bandwidth of the sink by the proposed congestion control algorithm. Via Lyapunov function, the validity of the proposed algorithm is shown under the varying network topologies. Ns simulation results indicate that the proposed algorithm restrains the congestion over the wireless sensor network, maintains a high throughput and a low delay time, and also improves the quality of service for the whole network.
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    Radiation Effects in Solar Cells and Optoelectronic Devices (2013)
    Hindawi
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    Publikationsdatum: 2013-09-20
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    Skyline-Based Aggregator Node Selection in Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-09-24
    Beschreibung: In order to achieve the equal usage of limited resources in the wireless sensor networks (WSNs), we must aggregate the sensor data before passing it to the base station. In WSNs, the aggregator nodes perform a data aggregation process. Careful selection of the aggregator nodes in the data aggregation process results in reducing large amounts of communication traffic in the WSNs. However, network conditions change frequently due to sharing of resources, computation load, and congestion on network nodes and links, which makes the selection of the aggregator nodes difficult. In this paper, we study an aggregator node selection method in the WSNs. We formulate the selection process as a top-k query problem, where we efficiently solve the problem by using a modified Sort-Filter-Skyline (SFS) algorithm. The main idea of our approach is to immediately perform a skyline query on the sensor nodes in the WSNs, which enables to extract a set of sensor nodes that are potential candidates to become an aggregator node. The experiments show that our method is several times faster compared to the existing approaches.
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    High Reliable Relay Selection Approach for QoS Provisioning in Wireless Distributed Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-09-24
    Beschreibung: In wireless distributed sensor networks, one open problem is how to guarantee the reliable relay selection based on the quality of services diversity. To address this problem, we focus on the reliable adaptive relay selection approach and adaptive QoS supported algorithm, based on which we present a Markov chain model, in consideration of different packet states and error control algorithm assignment. The mathematical analyses and NS-2 simulation results show that the proposed relay selection approach could perform better in terms of saturation throughput, reliability, and energy efficiency, compared with the traditional approaches. More importantly, the quality of real-time multimedia streaming is improved significantly, in terms of decodable frame ratio and delay.
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    Wireless Ad Hoc Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-09-24
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    Deployment Support for Sensor Networks in Indoor Climate Monitoring (2013)
    Hindawi
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    Publikationsdatum: 2013-09-24
    Beschreibung: Automatic recognition of personal comfort is critical in realizing autonomous control of building utilities. We can infer human comfort level based on indoor environmental conditions, such as temperature and humidity, collected through sensor networks. However, the majority of methods for optimally deploying sensor networks in indoor climate monitoring mainly focused on achieving accurate measurements such as temperature distribution map with the minimum cost. Indeed, for automatic recognition of comfort using machine learning, we need to collect datasets preserving as much of the discriminatory information for inferring personal comfort with the minimum cost. In this paper, we present a novel method of placing and minimizing sensor nodes for sensor networks in smart energy systems. We have developed ZigBee-based sensor nodes and collected temperature, humidity, and illumination dataset from 13 nodes for a week. Using the dataset, we group the sensor nodes into coherent clusters, and then select a representative node which has the maximum value of RSSI for each cluster and remove the other redundant sensors, reducing the number of sensor nodes deployed. To show the feasibility of the proposed method, we perform a classification analysis of building environment. The recognition accuracy decreased by 13 percent with 6 selected sensor nodes, compared to the result with all 13 sensor nodes.
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    On the Security of Data Collection and Transmission from Wireless Sensor Networks in the Context of Internet of Things (2013)
    Hindawi
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    Publikationsdatum: 2013-09-25
    Beschreibung: In the context of Internet of Things (IoT), multiple cooperative nodes in wireless sensor networks (WSNs) can be used to monitor an event, jointly generate a report and then send it to one or more Internet nodes for further processing. A primary security requirement in such applications is that every event data report be authenticated to intended Internet users and effectively filtered on its way to the Internet users to realize the security of data collection and transmission from the WSN. However, most present schemes developed for WSNs don’t consider the Internet scenario while traditional mechanisms developed for the Internet are not suitable due to the resource constraint of sensor nodes. In this paper, we propose a scheme, which we refer to as Data Authentication and En-route Filtering (DAEF), for WSNs in the context of IoT. In DAEF, signature shares are generated and distributed based on verifiable secret sharing cryptography and an efficient ID-based signature algorithm. Our security analysis shows that DAEF can defend against node compromise attacks as well as denial of service (DoS) attacks in the form of report disruption and selective forwarding. We also analyze energy consumption to show the advantages of DAEF over some comparable schemes.
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    A Utility-Based Rate Allocation of M2M Service in Heterogeneous Wireless Environments (2013)
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    Publikationsdatum: 2013-09-25
    Beschreibung: This paper presents a dynamic adaptive machine-to-machine (M2M) service rate allocation scheme for optimum traffic distribution in heterogeneous wireless environments (HWEs). According to the M2M service characteristics, it proposes the utility function, which forms a convex optimization problem that maximizes the utility of M2M service and can be solved by the Lagrange multiplier. The simulation results show the proposed method convergence, and it can achieve load balance with maximized throughput and minimized cost.
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    A Coding and Postprocessing Framework of Multiview Distributed Video for Wireless Video Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-09-25
    Beschreibung: In many surveillance application scenarios of wireless video sensor networks (WVSNs), a number of video sensors are deployed, and multidimension monitored the visual information in a region of interest, forming multiview videos. Since the power, computing capability, and bandwidth are very limited in WVSNs, the conventional multiview video coding method is no longer applicable. So multiview distributed video coding (MDVC) emerged and developed rapidly. In this paper, we propose a new multiview video coding and postprocessing framework for multiview videos. First, in coding scheme, motion intense regions (MIRs) and nonmotion intense regions (NMIRs) based on sum of absolute difference (SAD) criteria are distinguished. For the MIR, the side information (SI) is generated by fusion temporal SI and interview spatial SI at the pixel level. But for the NMIR, the temporal SI is directly use as the ultimate SI. Then, to further improve the quality of the decoded image, an image postprocessing scheme is designed by using deblocking and deringing artifact filters on decoded image. Finally, a set of experimental results show that the proposed fusion SI approach can bring improvements up to 0.2–0.5 dB when compares with only temporal SI used. The subsequent decoded videos postprocessing simulation proves that the proposed postprocessing scheme can provide an additional improvement of about 0.1 dB to the decoded video sequences.
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    Delay-Driven Routing for Low-Duty-Cycle Sensor Networks (2013)
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    Publikationsdatum: 2013-09-25
    Beschreibung: Duty-cycled operation has been introduced as an efficient way to preserve nodes energy and prolong network lifetime for wireless sensor networks. However, such networks are often logically disconnected since there is a limited number of active nodes within a period of time. Traditional routing algorithms, which have been designed for always-awake wireless networks, suffer excessive waiting time incurred by asynchronous schedule of nodes and cannot be applied to these time-dependent sensor networks. In this work, we study the optimization of delivery delay for low-duty-cycle sensor networks. Specially, we theoretically analyze the sleep latency in low-duty-cycle networks and present a new routing metric, which takes both lossy link and asynchronous schedule of nodes into consideration. Based on the metric, we propose delay-driven routing algorithms to find optimal forwarder in order to reduce delivery delay for source-to-sink communication. We compare our design against state-of-the-art routing algorithms derived in wireless networks through large-scale simulations and testbed experiments, which show that our algorithms can achieve a significant reduction in delivery delay.
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    Fisher Information of Mine Collapse Hole Detection Based on Sensor Nodes Connectivity (2013)
    Hindawi
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    Publikationsdatum: 2013-09-25
    Beschreibung: It is very important to detect a collapse hole for coal mine workers. The possibility of detecting the collapse hole using WSN is presented because the tunnel in coal mine is narrow and has poor working condition. Comparing three types of the hole detection methods, it is seen that the connectivity-based methods are used to detect coal mine collapse better than other methods. By establishing a 2D model of the collapse hole in coal mine, a class of algorithms for detecting the collapse hole in coal mine is described. Based on log-normal shadowing channel model, the accuracy of detecting the collapse hole in coal mine using Fisher information is analyzed. Numerical calculation shows that connectivity-based localization schemes are better to detect collapse hole of coal mine.
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    Distributional Fractal Creating Algorithm in Parallel Environment (2013)
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    Publikationsdatum: 2013-09-27
    Beschreibung: Nowadays, the fractal is used widely everywhere. Then, its creating time becomes an important study area for complex iteration functions because the escape-time algorithm (ETA), which is the most used algorithm in fractal creating, performs not so well in this condition. In this paper, in order to solve this problem, we improve ETA into the parallel environment and reach well performance. At first, we provide a separation method of ETA to reform it into a SIMC-MC2 grid. Secondly, we prove its correctness and compute the complexity of this novel parallel algorithm. Meantime, we separate an improved ETA which we have presented into the same parallel environment and compute its complexity. Additionally, theoretical and experimental results show the characteristics of this novel algorithm. Finally, the computational result shows that a novel environment is needed to decrease large manual allocation strategies, which block the improved benefit.
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    A+MAC: A Streamlined Variable Duty-Cycle MAC Protocol for Wireless Sensor Networks (2013)
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    Publikationsdatum: 2013-09-27
    Beschreibung: To improve the energy efficiency and the transmission performance of a sensor network MAC protocol under time varying traffic conditions, recent researches have adopted a variable duty cycle operation that makes each node dynamically adjust its own wakeup and sleep schedule according to a predefined trigger condition. However, most of the existing protocols still waste energy on a long preamble packet for waking up a receiver or long idle listening for checking potential communications. To address the energy waste problem, this paper introduces a hybrid MAC protocol called A+MAC that exploits a complementary cooperation between CSMA/CA and preamble sampling. In A+MAC CSMA/CA is used for carrying out communication processes, and preamble sampling is used for checking potential communications. Therefore, A+MAC minimizes both idle listening and the length of a preamble packet by exploiting a short preamble that makes nodes check only the event occurrence. A+MAC also optimizes control packet formats and eliminates both virtual carrier sensing and a separate clock synchronization period from conventional CSMA/CA based MAC protocols. We evaluated both the energy and the network performance of the protocol by using both NS-2 and MICA2 platforms. Our experimentation results show that A+MAC can achieve an order of magnitude energy savings while providing near optimal latency compared to the existing solutions.
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    Design and Analysis of High-Performance Smart Card with HF/UHF Dual-Band RFID Tag and Memory Functions (2013)
    Hindawi
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    Publikationsdatum: 2013-09-30
    Beschreibung: In this paper, we introduce a novel design of high-performance smart card with HF/UHF dual-band RFID tag to overcome frequency interference problem. Firstly, we have designed and tested a UHF RFID tag using a simulation software system. In the smart card hardware design stage, we connect a HF antenna and a UHF antenna and place them in one inlay sheet. Using a spectrum analyzer, we systematically adjust the antenna pattern to detect the optimal patterns that fit the impedance of the RFID chip. We evaluate the performance of the resulting smart card with standard RFID testers. The experiments show that our proposed RFID tag outperforms other dual-band RFID tags and maintains itself in a reasonable size. Moreover, we increase IC chip's memory capacity to resolve security-related problems when RFID tags are used in a financial transaction. We firstly exploit an IC contact protruded from the card to add an additional memory, and we integrate functions of the RFID tag to use the equipped memory through the induced current of the contact. The implemented prototype of our proposal can accommodate an extended memory ranging from one gigabyte up to four gigabytes.
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    Handing Optimization Energy Consumption in Heterogeneous Wireless Sensor Networks (2013)
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    Publikationsdatum: 2013-09-30
    Beschreibung: This paper presents an integer linear programming model devoted to optimize the energy consumption efficiency in heterogeneous wireless sensor networks. This model is based upon a schedule of sensor allocation plans in multiple time intervals subject to coverage and connectivity constraints. By turning off specifics sets of redundant sensors in each time interval, it is possible to reduce the total energy consumption in the network and, at the same time, avoid partitioning the whole network by losing some strategic sensors too prematurely. Since the network is heterogeneous, sensors can sense different phenomena from different demand points, with different sample rates. By resorting to this model, it is possible to provide extra lifetime to heterogeneous wireless sensor networks, reducing their setup and maintenance costs. This is an important issue to be considered when deploying sensor devices in hostile and inaccessible environments.
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    Dye-Sensitized Solar Cell Based on Polyaniline/Multiwalled Carbon Nanotubes Counter Electrode (2013)
    Hindawi
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    Publikationsdatum: 2013-09-30
    Beschreibung: This work presented the successful fabrication of dye-sensitized solar cell using polyaniline base (EB), multiwalled carbon nanotubes (MWCNTs), organic dye (rhodamine B or riboflavin), zinc oxide (ZnO), and indium tin oxide (ITO). The electrical properties of the resultant devices were investigated by measuring the current density voltage (-), capacitance voltage (-), and impedance measurements under both dark and illuminated conditions. The photovoltaic cell characteristics, that is, open circuit voltage (), short circuit current density (), and energy conversion efficiency (), were evaluated under illumination and were found to be 0.48 mA/cm2, 400 mV, and 0.224%, respectively, for ITO/EB-MWCNTs/ZnO-rhodamine B/ITO heterostructure. Using impedance spectra, it was found that the series resistances of this type of solar cell are 62 and 60 Ω under darkness and illumination, respectively.
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    Application of Baro-Altimeter Sensor in Emergency Positioning and Navigation Based on Compass GEO Satellites (2013)
    Hindawi
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    Publikationsdatum: 2013-09-30
    Beschreibung: Frame synchronization time of geostationary Earth orbit (GEO) satellites is faster than that of incline geosynchronous satellite orbit and medium Earth orbit satellites in Beidou navigation satellite system (BDS). So time to first fix can be reduced greatly with GEO satellites (GEOs) to provide emergency positioning service during the cold start process. Meanwhile, GEOs can also be utilized to provide radio determination satellite services. Therefore, it is meaningful to research the emergency positioning algorithm based on GEOs. However, due to the poor geometry of the GEOs, the availability and accuracy degrade distinctly. To solve this problem, a low-cost high resolution MS5534B barometric (baro-) module is applied to BDS. Firstly, the principle of emergency positioning based on a baro-altimeter sensor and its performance such as the accuracy are elaborated. Then the effects of baro-altimeter sensor measurement error on positioning are analyzed. Finally, after analyzing the limitation of the conventional algorithms, a new high-accuracy emergency positioning algorithm with baro-altimeter sensor aiding is proposed, which is not limited by the integration and user’s altitude. In comparison to the conventional algorithms, the stimulant and experimental results validate the effectiveness, robustness, and higher performance of the proposed algorithms incorporated with sensors.
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    A Betweenness Calibration Topology Optimal Control Algorithm for Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-10-01
    Beschreibung: In self-organized wireless sensor networks (WSNs), any two sensor nodes can connect if they are placed in each other's communication range. Therefore, the physical topology of WSNs is usually a strongly connected topology. Sensor nodes should frequently receive and process data from their large number of neighbors, which will consume great amounts of energy. Shocking wireless channel collision also causes low throughput and high loss packets ratio during data transmission. To improve the transmission performance and save scarce energy, a logical topology generating from the physical one is necessary for the self-organized WSNs. Based on the complex network theory, this paper proposed a novel betweenness addition edges expansion algorithm (BAEE). With betweenness calibration, BAEE algorithm expanded the minimum-cost edges to optimize the network topology. Two performance metrics-connectivity functions, robustness function and efficiency function , were utilized to evaluate the network capability of the robustness and invulnerability. is the parameter to measure the topology connectivity, and is the parameter to evaluate the network exchanging information capability. Based on the simulation under various random failures and intentional attack scenarios, BAEE can effectively optimize WSNs' topology and improve the network's robust connectivity and extremely efficient exchanging information capability.
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    MFT-MAC: A Duty-Cycle MAC Protocol Using Multiframe Transmission for Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-10-01
    Beschreibung: In many sensor network applications, energy efficiency and latency are major design criteria because battery-operated sensor nodes limit network lifetime. In this paper, we propose a new contention-based duty-cycle MAC protocol using a synchronized approach for use in wireless sensor networks. In the proposed MFT-MAC protocol, we use a control frame that considers the number of DATA frames to be transmitted to the next node in order to improve the energy efficiency and reduce the end-to-end delay. During the SLEEP period, each node transmits multiple DATA frames to the next node through the use of the control frame. The performance of the proposed MAC protocol is confirmed through the use of NS-2 simulator.
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    Security Analysis of Scalable Block Cipher PP-1 Applicable to Distributed Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-10-02
    Beschreibung: PP-1 is a scalable block cipher which can be implemented on a platform with limited resource. In this paper, we analyze the security of PP-1 by using truncated differential cryptanalysis. As concrete examples, we consider four versions of PP-1, PP-1/64, PP-1/128, PP-1/192, and PP-1/256. Our attack is applicable to full-round versions of them, respectively. The proposed attacks can recover a secret key of PP-1 with the computational complexity which is faster than the exhaustive search. These are the first known cryptanalytic results on PP-1.
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    A Microseismic/Acoustic Emission Source Location Method Using Arrival Times of PS Waves for Unknown Velocity System (2013)
    Hindawi
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    Publikationsdatum: 2013-10-04
    Beschreibung: To eliminate the location error of MS/AE (microseismic/acoustic emission) monitoring systems caused by the measurement deviations of the wave velocity, a MS/AE source location method using P-wave and S-wave arrivals for unknown velocity system (PSAFUVS) was developed. Arrival times of P-wave and S-wave were used to calculate and fit the MS/AE source location. The proposed method was validated by numerical experimentations. Results show that the proposed method without the need for a premeasured wave velocity has a reasonable and reliable precision. Effects of arrival errors on location accuracy were investigated, and it shows location errors enlarged rapidity with the increase of arrival errors. It is demonstrated the proposed method can not only locate the MS/AE source for unknown velocity system but also determine the real time PS waves velocities for each event in rockmass.
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    Low Mismatch Key Agreement Based on Wavelet-Transform Trend and Fuzzy Vault in Body Area Network (2013)
    Hindawi
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    Publikationsdatum: 2013-06-07
    Beschreibung: Body area network (BAN) is an emerging branch of wireless sensor networks for personalized applications in many fields, such as health monitoring. The services in BAN usually have a high requirement on security, especially for the medical diagnosis, which involves private information. With limitations of power and computation capabilities, one of the main challenges to ensure security in BAN is how to generate or distribute a shared key between nodes for lightweight symmetric cryptography. The current research almost exploits the randomness and distinctiveness (characteristics) of physiological signals to solve the key generation problem. However, it needs the help of additional hardware support and has the constraint on positions deployment, to acquire vital signals, which will bring the high cost and hardness to implementation of real system. To avoid the above problems, this paper presents a novel key generation scheme and a key distribution protocol, both of which are only based on wireless modules equipped on sensors. By exploiting the high correlation of received signal strength index (RSSI) between peer-to-peer communications, our scheme can provide a shared symmetric cryptographic key under the presence of an eavesdropper. We conduct experiments on the real Telosb nodes, and the results demonstrate that our proposed methods have a good performance on security.
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    How Much Delay Has to Be Tolerated in a Mobile Social Network? (2013)
    Hindawi
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    Publikationsdatum: 2013-06-10
    Beschreibung: Message delivery in a mobile social network (MSN) is difficult due to the fact that the topology of such network is sparse and unstable. Various routing schemes for MSNs were proposed to make the message delivery robust and efficient. However, little research has been conducted to explore how much delay has to be tolerated for the message delivery from the source to the destination. Since the social relationships among nodes are stable during a certain period of time, it is expected that the delay of message delivery in MSNs could be modeled with a probability model. In this paper, we take the first step to address this issue. We firstly extract three routing models from the existing routing schemes for MSNs and then develop the probability models of the message transmission delay for each abstract routing model. The simulation results show that the theoretical models match very well the simulation trace statistics.
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    Characterization of Natural Dye Extracted from Wormwood and Purple Cabbage for Dye-Sensitized Solar Cells (2013)
    Hindawi
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    Publikationsdatum: 2013-06-10
    Beschreibung: This study used natural dyes as sensitizers of dye-sensitized solar cells (DSSCs) to replace expensive chemical synthetic dyes. We prepared two natural dyes, chlorophyll dye and anthocyanin dye, by extracting them from wormwood and purple cabbage, respectively. Moreover, we mixed the prepared chlorophyll dye and anthocyanin dye at 5 different volume ratios to form cocktail dyes. For preparation of photoelectrode, P25 TiO2 nanoparticles were used to prepare paste, which was coated on fluorine-doped tin oxide (FTO) conductive glass by the spin coating method at different spin coating speeds in order to form TiO2 thin films with different thicknesses. The DSSC prepared by the cocktail dye achieves photoelectric conversion efficiency (η) of 1.95%, open-circuit voltage () of 0.765 V, and short-circuit current density () of 5.83 mA/cm2. Moreover, the prepared DSSC sensitized solely by chlorophyll extract of wormwood achieved a photoelectric conversion efficiency (η) of 0.9%, whereas the DSSC sensitized solely by anthocyanin extract of purple cabbage achieved a photoelectric conversion efficiency of 1.47%, achieving the longest lifetime of electrons amongst these three dyes.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Energietechnik
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    Hilbert-Curve Based Data Aggregation Scheme to Enforce Data Privacy and Data Integrity for Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-06-13
    Beschreibung: Data aggregation techniques have been proposed for wireless sensor networks (WSNs) to address the problems presented by the limited resources of sensor nodes. The provision of efficient data aggregation to preserve data privacy is a challenging issue in WSNs. Some existing data aggregation methods for preserving data privacy are CPDA, SMART, the Twin-Key based method, and GP2S. These methods, however, have two limitations. First, the communication cost for network construction is considerably high. Second, they do not support data integrity. There are two methods for supporting data integrity, iCPDA and iPDA. But they have high communication cost due to additional integrity checking messages. To resolve this problem, we propose a novel Hilbert-curve based data aggregation scheme that enforces data privacy and data integrity for WSNs. To minimize communication cost, we utilize a tree-based network structure for constructing networks and aggregating data. To preserve data privacy, we make use of both a seed exchange algorithm and Hilbert-curve based data encryption. To support data integrity, we use an integrity checking algorithm based on the PIR technique by directly communicating between parent and child nodes. Finally, through a performance analysis, we show that our scheme outperforms the existing methods in terms of both energy efficiency and privacy preservation.
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    Wireless Sensor Networks and the Internet of Things (2013)
    Hindawi
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    Publikationsdatum: 2013-06-11
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    A Secret Sharing-Based Key Management in Hierarchical Wireless Sensor Network (2013)
    Hindawi
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    Publikationsdatum: 2013-06-07
    Beschreibung: Wireless sensor networks (WSNs) are subject to various attacks because of the vulnerable environment, limited recourse, and open communication channel. To protect WSNs, in this paper, we present a Secret sharing-based key management (SSKM). SSKM utilizes the advantages of hierarchical architecture and adopts two-level key management and authentication mechanism, which can efficiently protect the allover network communication security and survivability. Different from previous works, the SSKM distributes keys based on secret sharing mechanism by the clustered architecture, which not only localizes the key things but also keeps scalability. The SSKM provides various session keys, the network key for base station (BS) and cluster heads (CHs); the cluster key between the cluster head and member nodes. The SSKM dynamically generates different keys based on different polynomials from BS in different periods which can protect the network from the compromised nodes and reduce the high probability of the common keys. The security analysis shows that the SSKM can prevent several attacks effectively and reduce the energy consumption.
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    APP: An Ultralightweight Scheme to Authenticate ONS and Protect EPC Privacy without Cryptography in EPCglobal Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-06-10
    Beschreibung: EPCglobal network is used to share product data between trading partners, which was proposed by EPCglobal. Object Name Service (ONS) in EPCglobal framework raises two critical security risks: the authenticity of IP addresses for Physical Markup Language (PML) servers and the privacy of Electronic Product Codes (EPCs). Existing work considers either the IP address authentication or the EPC privacy. In addition, that work mainly relies on cryptographic tools, in which key distribution is not a trivial task and also causes a large amount of computation overhead. In this paper, we make the first attempt to solve those two security risks together without relying cryptography. We propose a scheme, namely, APP (authenticate ONS and protect EPC privacy), to guarantee the authenticity of IP addresses for PML servers as well as EPC privacy and to maintain ultralightweight computation cost. Moreover, we give formal definition of the authenticity and the privacy in ONS context. The security achievements are strictly analyzed and proved. The extensive analysis results justify the applicability of the proposed scheme.
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    On the Security of Certificateless Signature Schemes (2013)
    Hindawi
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    Publikationsdatum: 2013-06-10
    Beschreibung: Wireless Sensor Network (WSN) has proved its presence in various real time applications and hence the security of such embedded devices is a vital issue. Certificateless cryptography is one of the recent paradigms to provide security. Certificateless public key cryptography (CL-PKC) deals effectively with the twin issues of certificate management in traditional public key cryptography and key escrow problem in identity-based cryptography. CL-PKC has attracted special attention in the field of information security as it has opened new avenues for improvement in the present security architecture. Recently, Tsai et al. proposed an improved certificateless signature scheme without pairing and claimed that their new construction is secure against different kinds of attacks. In this paper, we present a security analysis of their scheme and our results show that scheme does not have resistance against malicious-KGC attack. In addition, we have found some security flaws in the certificateless signature scheme of Fan et al. and proved the scheme vulnerable to Strong Type I attack.
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    Energy-Efficiency of Cooperative Communication with Guaranteed E2E Reliability in WSNs (2013)
    Hindawi
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    Publikationsdatum: 2013-04-10
    Beschreibung: This paper addresses the energy efficiency of cooperative communication in WSN. We first establish the energy model of single-hop WSN. It is found that the cooperative communication is more suitable for harsh transmission environment with long-haul distance. The energy consumption per bit is numerically minimized by finding the optimal broadcasting BER and the number of cooperative nodes. Then, we expand the conclusion to the multihop scenario where “energy hole” dominates the longevity of WSN. To mitigate the energy consumption in the hotspots, as well as to keep the promised reliability, we adjust the transmission BER of the clusters according to the hops between the sink and cluster. On one hand, the statistical reliability is met. On the other hand, the energy consumed is converted from the nearer cluster (from the sink) to the farther ones. The network lifetime is thus optimized.
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    Traffic Priority and Load Adaptive MAC Protocol for QoS Provisioning in Body Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-03-22
    Beschreibung: Body sensor networks (BSNs) carry heterogeneous traffic types having diverse QoS requirements, such as delay, reliability and throughput. In this paper, we design a priority-based traffic load adaptive medium access control (MAC) protocol for BSNs, namely, PLA-MAC, which addresses the aforementioned requirements and maintains efficiency in power consumption. In PLA-MAC, we classify sensed data packets according to their QoS requirements and accordingly calculate their priorities. The transmission schedules of the packets are determined based on their priorities. Also, the superframe structure of the proposed protocol varies depending on the amount of traffic load and thereby ensures minimal power consumption. Our performance evaluation shows that the PLA-MAC achieves significant improvements over the state-of-the-art protocols.
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    Synthesis of Nanostructured Anatase Mesoporous Membranes with Photocatalytic and Separation Capabilities for Water Ultrafiltration Process (2013)
    Hindawi
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    Publikationsdatum: 2013-03-22
    Beschreibung: In this work, the nanostructured anatase mesoporous membranes were prepared for water ultrafiltration (UF) process with photocatalytic and physical separation capabilities. A macroporous substrate was synthesized from α-Al2O3, then a colloidal titania sol was used for the preparation of the intermediate layer. Also, the membrane top layer was synthesized by deposition and calcination of titania polymeric sol on the intermediate layer. The characterization was performed by DLS, TG-DTA, XRD, BET, FESEM, TEM, and AFM techniques. Also, the filtration experiments were carried out based on separation of methyl orange from aqueous solution by a membrane setup with a dead-end filtration cell. Photocatalytic activity of the membranes was evaluated by methyl orange photodegradation using UV-visible spectrophotometer. The mean particle size of the colloidal and polymeric sols was 14 and 1.5 nm, respectively. The anatase membranes exhibited homogeneity, with the surface area of 32.8 m2/g, the mean pore size of 8.17 nm, and the crystallite size of 9.6 nm. The methyl orange removal efficiency by the mesoporous membrane based on physical separation was determined to be 52% that was improved up to 83% by a coupling photocatalytic technique. Thus, the UF membrane showed a high potential due to its multifunctional capability for water purification applications.
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    OPCPP: An Online Plug-Configure-Play Experiment Platform for WSN (2013)
    Hindawi
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    Publikationsdatum: 2013-04-03
    Beschreibung: Wireless sensor network (WSN) experiment platforms are used for teaching, research, and development of WSN. However, existing WSN experiment platforms generally have the following disadvantages: tedious manual operations, invasive measurement method, poor sensor self-awareness, and low resource utilization rate. To address the above problems, this paper proposes OPCPP, an online Plug-Configure-Play experiment platform for WSN. It has four prominent strongpoints: in-application programming in batch, noninvasive measurement method, sensor self-awareness, and remote operation. OPCPP has been used in eight colleges in China for teaching course of “internet of things” till now. We also develop a sensor-aware ZigBee-based smart home system prototype based on OPCPP.
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    Novel MAC Protocol and Middleware Designs for Wearable Sensor-Based Systems for Health Monitoring (2013)
    Hindawi
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    Publikationsdatum: 2013-04-10
    Beschreibung: We propose a middleware platform built on wireless USB (WUSB) over wireless body area networks (WBAN) hierarchical protocol for wearable health-monitoring systems (WHMS). The proposed middleware platform is composed of time-synchronization and localization solutions. It is executed on the basis of WUSB over WBAN protocol at each wearable sensor node comprising the WHMS. In the platform, firstly, the time-synchronization middleware is executed. After that, a WHMS host calculates the location of a receiving sensor node by using the difference between the times at which the sensor node received different WBAN beacon frames sent from the WHMS host. The WHMS host interprets the status and motion of the wearable body-sensor objects.
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    Selected Papers from “The 6th China Conference of Wireless Sensor Networks” (2013)
    Hindawi
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    Publikationsdatum: 2013-04-08
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    Ultrasonic Sensor-Based Personalized Multichannel Audio Rendering for Multiview Broadcasting Services (2013)
    Hindawi
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    Publikationsdatum: 2013-04-09
    Beschreibung: An ultrasonic sensor-based personalized multichannel audio rendering method is proposed for multiview broadcasting services. Multiview broadcasting, a representative next-generation broadcasting technique, renders video image sequences captured by several stereoscopic cameras from different viewpoints. To achieve realistic multiview broadcasting, multichannel audio that is synchronized with a user’s viewpoint should be rendered in real time. For this reason, both a real-time person-tracking technique for estimating the user’s position and a multichannel audio rendering technique for virtual sound localization are necessary in order to provide realistic audio. Therefore, the proposed method is composed of two parts: a person-tracking method using ultrasonic sensors and a multichannel audio rendering method using MPEG Surround parameters. In order to evaluate the perceptual quality and localization performance of the proposed method, a MUSHRA listening test is conducted, and the directivity patterns are investigated. It is shown from these experiments that the proposed method provides better perceptual quality and localization performance than a conventional multichannel audio rendering method that also uses MPEG Surround parameters.
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    A Multipopulation Firefly Algorithm for Correlated Data Routing in Underwater Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-04-01
    Beschreibung: Low data delivery efficiency and high energy consumption are the inherent problems in Underwater Wireless Sensor Networks (UWSNs) characterized by the acoustic channels. Existing energy-efficient routing algorithms have been shown to reduce energy consumption of UWSNs to some extent, but still neglect the correlation existing in the local data of sensor nodes. In this paper, we present a Multi-population Firefly Algorithm (MFA) for correlated data routing in UWSNs. We design three kinds of fireflies and their coordination rules in order to improve the adaptability of building, selecting, and optimization of routing path considering the data correlation and their sampling rate in various sensor nodes. Different groups of fireflies conduct their optimization in the evolution in order to improve the convergence speed and solution precision of the algorithm. Moreover, after the data packets are merged during the process of routing path finding, MFA can also eliminate redundant information before they are sent to the sink node, which in turn saves energy and bandwidth. Simulation results have shown that MFA achieves better performance than existing protocols in metrics of packet delivery ratio, energy consumption, and network throughput.
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    A Counterattack-Detection Scheme in Transmission Time-Based Wormhole Detection Methods (2013)
    Hindawi
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    Publikationsdatum: 2013-04-01
    Beschreibung: In recent years, the Mobile Ad hoc Network (MANET) is getting more important and is being utilized in various fields. However, routing-disruption attacks have become a serious problem for MANET. In various routing-disruption attack detection methods, transmission time-based methods can detect wormhole attacks efficiently. Attackers might fabricate a time stamp for a Route Request Packet (RREQ) or Route Reply Packet (RREP) to evade wormhole detection methods. To resolve this weakness, we propose a counterattack-detection scheme in transmission time-based wormhole detection methods. In this paper, we show that it is possible for an attacker to find an effective counterattack against wormhole detection methods, so we provide a counterattack-detection scheme. In the first phase, our proposed method uses the transmission time per hop extracted from a RREQ. If the attackers fabricate the RREQ’s starting time to evade our proposed method, we can detect this counterattack using the RREQ’s transmission time in the second phase, because the fabricated starting time makes the transmission time shorter than the original transmission time. The simulation shows that our proposed method has high reliability for detecting both wormhole attacks and the attacker’s counterattack.
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    A Hybrid Cluster-Based Target Tracking Protocol for Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-04-01
    Beschreibung: Target tracking is a typical and important application of wireless sensor networks (WSNs). In consideration of the network scalability and energy efficiency for target tracking in large-scale WSNs, it has been employed as an effective solution by organizing the WSNs into clusters. However, tracking a moving target in cluster-based WSNs suffers a boundary problem when the target moves across or along the boundaries of clusters, as the static cluster membership prevents sensors in different clusters from sharing information. In this paper, we propose a novel mobility management protocol, called hybrid cluster-based target tracking (HCTT), which integrates on-demand dynamic clustering into a cluster-based WSN for target tracking. By constructing on-demand dynamic clusters at boundary regions, nodes from different static clusters that detect the target can temporarily share information, and the tracking task can be handed over smoothly from one static cluster to another. As the target moves, static clusters and on-demand dynamic clusters alternately manage the target tracking task. Simulation results show that the proposed protocol performs better in tracking the moving target when compared with other typical target tracking protocols.
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    A Fuzzy Collaborative Sensor Network for Semiconductor Manufacturing Cycle Time Forecasting (2013)
    Hindawi
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    Publikationsdatum: 2013-04-01
    Beschreibung: Network based sensing has become an important field of research, and it is expected that new applications of remote sensing will be developed. A fuzzy collaborative sensor network is developed in this study to predict the cycle time of a job in a semiconductor manufacturing factory, which is an important task for the factory. In the fuzzy collaborative sensor network, each sensor detects the status of a particular job as well as various environmental conditions present in the factory and uses a fuzzy neural network to analyze the received information. Each sensor communicates its settings and forecasting results to other sensors with the aid of a central control unit. According to the experimental results, the aggregate forecasting performance was considerably improved through the sensors’ collaboration.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Publiziert von Hindawi
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    The Novel Authentication Scheme Based on Theory of Quadratic Residues for Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-04-01
    Beschreibung: Being one of the main technologies for Internet of Things (IoT), wireless sensor network is absolutely critical and plays an increasingly important role in the development of Internet of Things. Wireless sensor network is mobile network composed of sensor nodes with limited resources, like computation capability, energy, memory storage, and communication capability. Its characteristic results in that the security of wireless sensor network faces a great challenge. Hence, the security of wireless sensor network is an important issue for the development of IoT and shall be focused on. In this paper, a novel authentication scheme is proposed for wireless sensor networks based on theory of quadratic residues. It is making the use of master key to achieve simple symmetric cryptographic primitives and authentication operation and reach the aims of great resistance against the attacks and low energy consumption. Then the proposed scheme is compared with other network-wide key management schemes, obtaining better results in the aspects of security, efficiency, and scalability.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
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  • 88
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    A Self-Adaptive Regression-Based Multivariate Data Compression Scheme with Error Bound in Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-04-01
    Beschreibung: Wireless sensor networks (WSNs) have limited energy and transmission capacity, so data compression techniques have extensive applications. A sensor node with multiple sensing units is called a multimodal or multivariate node. For multivariate stream on a sensor node, some data streams are elected as the base functions according to the correlation coefficient matrix, and the other streams from the same node can be expressed in relation to one of these base functions using linear regression. By designing an incremental algorithm for computing regression coefficients, a multivariate data compression scheme based on self-adaptive regression with infinite norm error bound for WSNs is proposed. According to error bounds and compression incomes, the self-adaption means that the proposed algorithms make decisions automatically to transmit raw data or regression coefficients, and to select the number of data involved in regression. The algorithms in the scheme can simultaneously explore the temporal and multivariate correlations among the sensory data. Theoretically and experimentally, it is concluded that the proposed algorithms can effectively exploit the correlations on the same sensor node and achieve significant reduction in data transmission. Furthermore, the algorithms perform consistently well even when multivariate stream data correlations are less obvious or non-stationary.
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  • 89
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    A Fault-Tolerant Method for Enhancing Reliability of Services Composition Application in WSNs Based on BPEL (2013)
    Hindawi
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    Publikationsdatum: 2013-04-01
    Beschreibung: In recent years, some approaches have been presented for the seamless integration of WSNs with the existing, widely deployed SOA technologies such as XML, Web services, and the Business Process Execution Language (BPEL) to build a wireless sensor networks service application. However, there a great challenge on fault tolerant in WSNs. In this paper, we present our framework and approach to enhance the reliability of service composition applications in WSNs through modeling and analyzing a wireless sensor networks service application based on BPEL with exception handler and compensation mechanism. At first, we analyze all possible states during the execution of BPEL instance in WSNs. Then, we present a state framework for modeling execution context in BPEL instance in WSNs. Based on this framework, we analyze state transition and operational semantics in the case of both correct execution and exceptional execution of BPEL instance in WSNs. Furthermore, we propose the state transition models for three types of activities in BPEL instance. In the end, we present a formal approach to model the execution context in BPEL for WSNs. Using this formal model, one can describe and analyze the control flow result from the exception handler and compensation mechanism in BPEL instance for WSNs.
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  • 90
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    Energy-Efficient Self-Organized Clustering with Splitting and Merging for Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-04-01
    Beschreibung: Energy efficiency is one of the most important issues for WSNs, because the battery of each wireless sensor node cannot be recharged or replaced. Therefore, all batteries have to be well managed, in order to provide a long network lifetime, as well as to reduce energy consumption for WSNs, particularly in clustering and routing. In this paper, we propose an energy-efficient self-organized clustering model with splitting and merging (EECSM), which performs clustering and then splits and merges clusters for energy-efficient cluster-based routing. EECSM uses information of the energy state of sensor nodes, in order to reduce energy consumption and maintain load balance. We show the validity of splitting and merging of clusters and then compare the performance of the proposed EECSM with that of a well-known cluster-based self-organization routing protocol for WSNs. The results of our experiment show good performance of EECSM, in terms of network lifetime, residual energies, scalability, and robustness.
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  • 91
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    A Multichannel Cross-Layer Architecture for Multimedia Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-04-01
    Beschreibung: Depending upon the technological developments, the same fast evolution has occurred in the structures of sensor networks, their composing devices which are sensor nodes, and their application areas. Those tiny, energy-constrained, mostly non-real-time data transmitting sensor nodes have evolved to more energy-containing, camera-adapted, real-time multimedia-data-transmitting devices. Developments in the usage areas and the capabilities have revealed some other problems such as time limited data transmission. In this paper, we propose a multichannel cross-layer architecture for Quality of Service (QoS) constrained multimedia sensor networks. The proposed architecture considers both the time and energy efficiency concepts. Energy efficiency is succeeded by ensuring the fair load distribution among the nodes during a real-time multimedia packet stream transmission. Besides ensuring the fair load distribution, on-time packet transmission is also assured by constructing the paths with a hard reservation technique depending on the predetermined QoS constraints. Simulations show that the proposed architecture provides higher performance than the Greedy approach and the LEERA scheme.
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  • 92
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    Optical and Electrical Properties of the Different Magnetron Sputter Power 300°C Deposited -ZnO Thin Films and Applications in p-i-n -Si:H Thin-Film Solar Cells (2013)
    Hindawi
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    Publikationsdatum: 2013-04-01
    Beschreibung: A compound of ZnO with 3 wt% Ga2O3 (ZnO : Ga2O3 = 97 : 3 in wt%, GZO) was sintered at C as a target. The GZO thin films were deposited on glass using a radio frequency magnetron sputtering system at C by changing the deposition power from 50 W to 150 W. The effects of deposition power on the crystallization size, lattice constant (c), resistivity, carrier concentration, carrier mobility, and optical transmission rate of the GZO thin films were studied. The blue shift in the transmission spectrum of the GZO thin films was found to change with the variations of the carrier concentration because of the Burstein-Moss shifting effect. The variations in the optical band gap () value of the GZO thin films were evaluated from the plots of , revealing that the measured value decreased with increasing deposition power. As compared with the results deposited at room temperature by Gong et al., (2010) the C deposited GZO thin films had apparent blue shift in the transmission spectrum and larger value. For the deposited GZO thin films, both the carrier concentration and mobility linearly decreased and the resistivity linearly increased with increasing deposition power. The prepared GZO thin films were also used as transparent electrodes to fabricate the amorphous silicon thin-film solar cells, and their properties were also measured.
    Print ISSN: 1110-662X
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Energietechnik
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  • 93
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    Moving Target Oriented Opportunistic Routing Algorithm in Vehicular Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-04-04
    Beschreibung: In vehicular networks, the multihop message delivery from information source to moving vehicles presents a challenging task due to many factors, including high mobility, frequent disconnection, and real-time requirement for applications. In this paper, we propose a moving target oriented opportunistic routing algorithm in vehicular networks for message delivery from information source to a moving target vehicle. In order to adapt the constantly changing topology of networks, the forwarding decisions are made locally by each intermediate vehicle based on the trajectory information of the target vehicle. The simulation and real trace experiment show that our design provides an efficient message delivery with a higher success ratio, shorter success time, and lower transmission overhead compared with other reference approaches.
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    Design and Implementation of the Prevention System of Molds Growth Using Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-09-06
    Beschreibung: Due to the advances in memory and processing capacity of embedded systems, wireless communications, and size of the devices, many researchers are growing more and more interested in wireless sensor networks (WSN). WSN have a large number of nodes with a sensor board, and wireless communication board, and have been applied to many fields. Summer is the season when much personal and property damage arises from various natural disasters such as the heat being reminiscent of subtropical climate and flooding from heavy rain due to global warming. This unusual temperature affects our lives much besides causing natural disasters. Recently, many problems have occurred with respect to hygiene and beauty of view especially due to growing of various molds in the residential environment. In the heat of summer, the damages from molds become serious due to the effect of temperature and humidity according to seasonal characteristics. In this paper, we build a wireless sensor network with some sensors such as temperature and humidity. And then we design and implement the prevention system of molds growth which can predict and prevent molds production in indoor environment.
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    Design and Manufacturing of a High-Precision Sun Tracking System Based on Image Processing (2013)
    Hindawi
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    Publikationsdatum: 2013-09-06
    Beschreibung: Concentration solar arrays require greater solar tracking precision than conventional photovoltaic arrays. This paper presents a high precision low cost dual axis sun tracking system based on image processing for concentration photovoltaic applications. An imaging device is designed according to the principle of pinhole imaging, making sun rays to be received on a screen through pinhole and to be a sun spot. The location of the spot is used to adjust the orientation of the solar panel. A fuzzy logic controller is developed to achieve this goal. A prototype was built, and experimental results have proven the good performance of the proposed system and low error of tracking. The operation of this system is independent of geographical location, initial calibration, and periodical regulations.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Energietechnik
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    Cooperative Processing Model for Wireless Sensor Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-09-09
    Beschreibung: Wireless sensor networks offer a distributed processing environment. Many sensor nodes are deployed in fields that have limited resources such as computing power, network bandwidth, and electric power. The sensor nodes construct their own networks automatically, and the collected data are sent to the sink node. In these traditional wireless sensor networks, network congestion due to packet flooding through the networks shortens the network life time. Clustering or in-network technologies help reduce packet flooding in the networks. Many studies have focused on saving energy in the sensor nodes because the limited available power leads to an important problem of extending the operation of sensor networks as long as possible. However, we focus on the execution time because clustering and local distributed processing already contribute to saving energy by local decision making. In this paper, we present a cooperative processing model based on the processing timeline. Our processing model includes validation of the processing, prediction of the total execution time, and determination of the optimal number of processing nodes for distributed processing in wireless sensor networks. The experiments demonstrate the accuracy of the proposed model, and a case study shows that our model can be used for the distributed application.
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  • 97
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    Photostabilization of Phenoxyacetic Acid Herbicides MCPA and Mecoprop by Hydroxypropyl-β-cyclodextrin (2013)
    Hindawi
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    Publikationsdatum: 2013-09-09
    Beschreibung: New strategies to reduce the environmental and economic costs of pesticides use are currently under study. Microencapsulation has been used as a versatile tool for the production of controlled release agricultural formulations. In this study, the photochemical degradation of the herbicides MCPA and mecoprop has been investigated in different aqueous media such as ultrapure and river water under simulated solar irradiation. To explore the possibility of introducing cyclodextrins in the herbicide formulations, the photodegradation study of the inclusion complexes of MCPA and mecoprop with (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD) was also performed. The half-lives of MCPA and mecoprop inclusion complexes were increased approximately by a factor of three related to the free molecules. Additionally, it has been shown that the photodegradation of MCPA and mecoprop is influenced by their structural features. The additional methyl group existing in mecoprop molecular structure has a positive influence on the stabilization of the radical intermediate formed in the first stage of photodegradation of both herbicides. The results found indicated that MCPA and mecoprop form inclusion complexes with HP-β-CD showing higher photostability compared to free herbicides indicating that HP-β-CD may serve as ingredient in these herbicide formulations.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Energietechnik
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    A Genetic QoS-Aware Routing Protocol for the Smart Electricity Networks (2013)
    Hindawi
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    Publikationsdatum: 2013-09-10
    Beschreibung: This paper presents a QoS-aware routing protocol suitable for distribution of smart electricity grids based on heterogeneous machine to machine communications. The distribution Smart Grid needs high performance communication networks capable of handling QoS, an issue that is addressed by the present paper. The proposed algorithm is a merger between a genetic algorithm (GA) and Ticket-Based Routing (TBR), which is an on-demand routing protocol for ad hoc networks that provide quality of service. A suitable parameterization of the GA parameters is needed in order to use this protocol in the coming Smart Grid networks. The resulting routing protocol, named genetic algorithm with TBR algorithm for Smart Grids (GATAS), is an adapted intelligent evolution of the TBR. The performance of TBR has been improved by reducing the overhead of routing packets in the network and by minimizing the communication latency due to its on-demand behavior. Experimental evidence indicates that the likelihood of finding the optimum route using multiobjective dynamic metrics increases when the genetic algorithm is applied. In this paper, the main simulation results on the parameterization carried out are discussed, and the proposed attributes of the GA are described.
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    Forecasting the Cell Temperature of PV Modules with an Adaptive System (2013)
    Hindawi
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    Publikationsdatum: 2013-09-10
    Beschreibung: The need to reduce energy consumptions and to optimize the processes of energy production has pushed the technology towards the implementation of hybrid systems for combined production of electric and thermal energies. In particular, recent researches look with interest at the installation of hybrid system PV/T. To improve the energy performance of these systems, it is necessary to know the operating temperature of the photovoltaic modules. The determination of the operating temperature is a key parameter for the assessment of the actual performance of photovoltaic panels. In the literature, it is possible to find different correlations that evaluate the referring to standard test conditions and/or applying some theoretical simplifications/assumptions. Nevertheless, the application of these different correlations, for the same conditions, does not lead to unequivocal results. In this work an alternative method, based on the employment of artificial neural networks (ANNs), was proposed to predict the operating temperature of a PV module. This methodology does not require any simplification or physical assumptions. In the paper is described the ANN that obtained the best performance: a multilayer perception network. The results have been compared with experimental monitored data and with some of the most cited empirical correlations proposed by different authors.
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    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Energietechnik
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    Effect of Hydrogen Content in Intrinsic a-Si:H on Performances of Heterojunction Solar Cells (2013)
    Hindawi
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    Publikationsdatum: 2013-09-10
    Beschreibung: Influences of hydrogen content in intrinsic hydrogenated amorphous silicon (i-a-Si:H) on performances of heterojunction (HJ) solar cells are investigated. The simulation result shows that in the range of 0–18% of the i-layer hydrogen content, solar cells with higher i-layer hydrogen content can have higher degree of dangling bond passivation on single crystalline silicon (c-Si) surface. In addition, the experimental result shows that HJ solar cells with a low hydrogen content have a poor a-Si:H/c-Si interface. The deteriorate interface is assumed to be attributed to (i) voids created by insufficiently passivated c-Si surface dangling bonds, (ii) voids formed by SiH2 clusters, and (iii) Si particles caused by gas phase particle formation in silane plasma. The proposed assumption is well supported and explained from the plasma point of view using optical emission spectroscopy.
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