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  • Institute of Electrical and Electronics Engineers (IEEE)  (13,913)
  • 2015-2019  (13,913)
  • 1955-1959
  • 1945-1949
  • 2017  (13,913)
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  • 2015-2019  (13,913)
  • 1955-1959
  • 1945-1949
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  • 1
    Publication Date: 2017-03-21
    Description: This paper presents an adaptive droop-based power-sharing control strategy. The primary objective is to control the sharing of the active power transmitted by a multiterminal voltage-source converter based high voltage direct current network among a number of onshore ac grids or offshore loads based on the desired percentage shares. The shared power is generated by remote generation plants (e.g., offshore wind farms) or is provided as surplus from ac grids. The desired percentage shares of active power are optimized by the system operator in order to fulfil the active power requirements of the connected grids with respect to meeting goals such as supporting energy adequacy, increasing renewable energy penetration, and minimizing losses. The control strategy is based on two hierarchal levels: voltage-droop control as the primary controller and an optimal-power flow based secondary (supervisory) controller for selecting the optimal droop reference voltages. Based on the dc voltage transient and steady-state dynamics, a methodology for choosing the droop gains for droop controlled converters has been developed. The proposed control strategy has been validated through simulation on the CIGRE B4 dc grid test system. The results confirmed the flexibility and effectiveness of the power-sharing control provided by the new control strategy.
    Print ISSN: 1949-3029
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 2
    Publication Date: 2017-03-21
    Description: This paper presents a new nonlinear current control strategy based on backstepping control and high-order sliding mode differentiator in order to employ distributed generation (DG) unit interfacing converters to actively compensate harmonics/interharmonics of local loads. The converter-based DG unit is connected to a weak grid (with uncertain impedance) and local load (that can be parametrically uncertain and topologically unknown) through an LCL filter. The proposed strategy robustly regulates the inverter output currents and delivers pure sinusoidal, three-phase balanced currents to the grid. The new controller demonstrates the robust performance and robust stability of the DG unit system with respect to the filter parameters uncertainties, grid impedance, grid frequency, and grid voltage as well as the unknown load dynamics that include unbalanced loads and nonlinear loads with harmonic and interharmonic currents. We should remark that the local compensation of the loads with interharmonic current using a DG unit system is first proposed in this paper. When compared with the popular parallel proportional resonant control technique, the proposed controller offers smoother transient responses and a lower level of current distortion. The performance of the proposed control strategy is verified in MATLAB/SimPowerSystems toolbox.
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    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 3
    Publication Date: 2017-03-21
    Description: Optimally dispatching photovoltaic (PV) inverters is an efficient way to avoid overvoltage in active distribution networks, which may occur in the case of the PV generation surplus load demand. Typically, the dispatching optimization objective is to identify critical PV inverters that have the most significant impact on the network voltage level. Following, it ensures the optimal set-points of both active power and reactive power for the selected inverters, guaranteeing the entire system operating constraints (e.g., the network voltage magnitude) within reasonable ranges. However, the intermittent nature of solar PV energy may affect the selection of the critical PV inverters and also the final optimal objective value. In order to address this issue, a two-stage robust centralized-optimal dispatch model is proposed in this paper to achieve a robust PV inverter dispatch solution considering the PV output uncertainties. In addition, the conic relaxation-based branch flow formulation and the column-and-constraint generation algorithm are employed to deal with the proposed robust optimization model. Case studies on a 33-bus distribution network and comparisons with the deterministic optimization approach have demonstrated the effectiveness of the proposed method.
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    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 4
    Publication Date: 2017-03-21
    Description: The dynamic economic dispatching of power system connected with multiple wind farms is a typical stochastic programming problem. How to model the randomness of wind power and how to solve this complex stochastic optimization problem are the key points. In this paper, copula theory is used to formulate the correlation of multiwind farms generation. Then, the dynamic economic dispatching model is founded with the fuel consumption, gas pollution emission fees, and electricity purchase costs as the optimized objective. The two-stage compensation algorithm is then introduced to solve the dispatching problem. In this algorithm, the conventional (nonstochastic) decision variables and stochastic variables are decoupled, which separate the dynamic dispatching model into two stage modes. The optimal dispatching result is worked out by iteration between the two stage models. Case studies on IEEE118-bus system and an actual provincial power grid show that the proposed algorithm can drastically reduce computational burden, and satisfy the actual requirements of engineering practice.
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  • 5
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    Publication Date: 2017-03-21
    Description: A single-stage flyback PV inverter with maximum power point tracking (MPPT) high-speed capability is presented in this paper. The proposed stand-alone photovoltaic energy system (SAPES) incorporates the use of hybrid MPPT to ensure peak energy harvesting under all weather conditions. The proposed hybrid MPPT method combines the conventional short current pulse (SCP) MPPT method and the perturb and observe (P&O) methods. Measurement of the offline parameter [short-circuit current of PV module ( ${I}_{rm sc}$ )] for SCP is made on the basis of the difference between the offline parameter and the instantaneous current of PV module ( ${I}_{rm pv}$ ). Use of a single power conversion stage is achieved by employing a modified flyback inverter operating in a discontinuous-conduction mode. The control structure of the conventional flyback inverter is also modified to incorporate the hybrid MPPT algorithm. The proposed SAPES method is tested using computer-aided simulations and real-time hardware in the loop experimentation using the dSPACE DS1104 board. The results obtained using the proposed systems are better than those for the conventional algorithms under the environmental conditions tested.
    Print ISSN: 1949-3029
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 6
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: The large-scale integration of a grid-scale energy storage and the increasing penetration of renewable resources motivate the development of techniques for determining the optimal ratings and locations of storage devices. This paper proposes a method for identifying the sites where energy storage systems should be located to perform spatio-temporal energy arbitrage most effectively and the optimal size of these systems. This method takes a centralized perspective where the objective is to minimize the sum of the expected operating cost and the investment cost of energy storage. It has been tested on a realistic 240-bus 448-line model of the Western Electricity Coordinating Council (WECC) interconnection. The influence on the results of the following parameters is analyzed: Maximum number of storage locations, maximum size of storage systems, capital cost of deploying storage, value assigned to spillage of renewable energy, marginal cost of conventional generation, and renewable generation capacity. These numerical results are used to characterize the benefits that energy storage can provide in prospective large-scale power systems with renewable generation.
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  • 7
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    Publication Date: 2017-03-21
    Description: In this study, we propose a novel distributed secondary control scheme for both voltage and frequency in autonomous microgrids. By incorporating predictive mechanisms into distributed generations, the secondary voltage control is converted to a tracker consensus problem of distributed model predictive control, with the synchronous convergence procedure for voltage magnitudes to the reference value drastically accelerated at a low communication cost. A sufficient local stability condition with the parameter analysis is established. Thus, a distributed proportional integral method combined with a finite-time observer to estimate the global reference information is presented in the frequency restoration while maintaining accurate active power sharing. Our approach accommodates model uncertainty, plug-and-play capability, and especially robustness against information update intervals, which is essential when the conventional method probably yields toward a poor performance. Meanwhile, the distributed architecture implemented on the local and neighboring information allows for a sparse communication network and eliminates the requirement for a centralized controller. Simulation results are provided to verify the effectiveness of the proposed control methodology.
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  • 8
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: This paper proposes an $mathrm{H}_{infty}$ robust current controller for doubly-fed induction-generator (DFIG)-based wind turbines subject to grid voltage distortions. The controller is to mitigate the impact of the grid voltage distortions on rotor currents with DFIG parameter perturbation. The grid voltage distortions considered include asymmetric voltage dips and grid background harmonics. An uncertain DFIG model is developed with uncertain factors originating from distorted stator voltage, and changed generator parameters due to the flux saturation effect, the skin effect, etc. Weighting functions are designed to efficiently track the unbalanced current components and the fifth and seventh background harmonics. The robust stability and robust performance of the proposed controller are verified by the structured singular value μ. The performance of the $mathrm{H}_{infty}$ robust current controller was demonstrated with a 1.5-MW DFIG model, showing its harmonics suppression ability with DFIG parameter perturbation and improved robustness.
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  • 9
    Publication Date: 2017-03-21
    Description: This paper presents a comprehensive sensitivity analysis to identify the uncertain parameters which significantly influence the decision-making process in distributed generation (DG) investments and quantify their degree of influence. To perform the analysis, a DG investment planning model is formulated as a novel multistage and multiscenario optimization problem. Moreover, to ensure tractability and make use of exact solution methods, the entire problem is kept as a mixed-integer linear programming optimization. A real-world distribution network system is used to carry out the analysis. The results of the analysis generally show that uncertainty as well as operational variability of the considered parameters have meaningful impacts on investment decisions of DG. The degree of influence varies from one parameter to another. But, in general, ignoring or inadequately considering uncertainty and variability in model parameters has a quantifiable cost. Hence, the analysis made in this paper can be very useful to identify the most relevant model parameters that need special attention in planning practices.
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  • 10
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Print ISSN: 2168-6831
    Topics: Architecture, Civil Engineering, Surveying , Electrical Engineering, Measurement and Control Technology , Geosciences , Computer Science
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  • 11
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    Publication Date: 2017-03-21
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  • 12
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    Publication Date: 2017-03-21
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  • 13
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: Hyperspectral image classification has been a vibrant area of research in recent years. Given a set of observations, i.e., pixel vectors in a hyperspectral image, classification approaches try to allocate a unique label to each pixel vector. However, the classification of hyperspectral images is a challenging task for a number of reasons, such as the presence of redundant features, the imbalance among the limited number of available training samples, and the high dimensionality of the data.
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  • 14
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
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  • 15
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
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  • 16
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: Land-cover mapping in remote sensing (RS) applications renders rich information for decision support and environmental monitoring systems. The derivation of such information increasingly relies on robust classification methods for identifying the complex land-cover area of different categories. Numerous classification techniques have been designed for the analysis of RS imagery. In this context, support vector machines (SVMs) have recently received increasing interest. However, the need for a small-size training set remains a bottleneck to design efficient supervised classifiers, while an adequate number of unlabeled data is readily available in RS images and can be exploited as a supplementary source of information. To fully leverage these precious unlabeled data, a number of promising advanced SVM-based methods, such as active SVMs, semisupervised SVMs (S3VMs), and SVMs combined with other algorithms, have been developed to analyze satellite imagery. In this literature review, we have surveyed these learning techniques to explore RS images. Moreover, we have provided the empirical evidences of SVMs and three representative techniques. It is our hope that this review will provide guidelines to future researchers to enhance further algorithmic developments in RS applications.
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  • 17
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
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  • 18
    Publication Date: 2017-03-21
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  • 19
    Publication Date: 2017-03-21
    Description: Since 2006, the Image Analysis and Data Fusion Technical Committee (IADF TC) of the IEEE Geoscience and Remote Sensing Society (GRSS) organizes a yearly Data Fusion Contest that aims to promote the use of new remote sensing data sources and stimulating new methodological developments [1]-[10].
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  • 20
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
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  • 21
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    Publication Date: 2017-03-21
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  • 22
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: Advertisement.
    Print ISSN: 1540-7977
    Electronic ISSN: 1558-4216
    Topics: Electrical Engineering, Measurement and Control Technology
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  • 23
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: In this letter, we focus on stub resonators embedded in plasmonic slot waveguides. The resonators have potential applications in optical interconnects and sensors. We fabricate the samples by electron beam lithography and lift-off. We use a scattering matrix-based model to quantify the optical power output from the samples. We measure the properties of the resonators by coupling light in and out of the slot waveguides by optical antennas, making use of a cross-polarization-based setup utilizing a supercontinuum source and a high numerical aperture objective lens operating in the telecom-wavelength range. Our model agrees well with the measured data. Furthermore, development on the stub resonators can be made by using the methods in this letter.
    Print ISSN: 1041-1135
    Electronic ISSN: 1941-0174
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  • 24
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: Advertisement.
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  • 25
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: Advertisement.
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  • 26
    Publication Date: 2017-03-21
    Description: The use of a fixed forward power as obtained during the calibration phase in a bulk current injection test, without monitoring the current, may cause damage on the equipment under test (EUT) with low impedances. In this paper, an accurate EUT model has been designed based on impedance investigation. This model can be used to predict the conducted susceptibility of a generic EUT. The model is first based on black-box approach; then, an interaction model is added to provide flexibility of several geometric parameters, which can be changed from one setup to another. This methodology leads to the combined approach, which shows a satisfactory agreement between simulations and measurements. According to the developed equations, the impedance matrix of the described model can be readily switched to modal one. Afterward, asymmetric dummy EUTs were investigated and the analytical equations used to predict differential mode due to common-mode voltage injection were validated.
    Print ISSN: 0018-9375
    Electronic ISSN: 1558-187X
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  • 27
    Publication Date: 2017-03-21
    Description: In this paper, we analyze the impact of characteristic impedance variations among standards on the accuracy of the thru-reflect-line (TRL) calibration technique. The impedance transformer method is adopted to derive the expressions of the calibration coefficient errors due to the manufacturing tolerances. It is found that three factors can affect the magnitude of the errors in the calibration coefficients (c/a and b terms), which are crucial to get the final calibrated results. The first factor is related to the original parameters of the error networks (test fixtures): the larger the insertion losses, the smaller the error in b ; the error in c/a may see an opposite trend if the error network is lossy instead of lossless. The second factor is denoted as the phase contribution (one of the three multipliers of the derived error expression): the magnitude of this error contributing item is approximately equal to the ratio of two hyperbolic sine functions, the variables of which are the length of Line and the length difference between Line and Thru, respectively. The third factor comes from the impedance differences between Thru and Line: the smaller the impedance variation, the smaller the error. The error analysis, presented here, can help engineers evaluate the calibration accuracy by analyzing the error contributing items. It also can be further used to guide test fixture designs to maximize TRL's error immunity to the transmission line characteristic impedance variations.
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  • 28
    Publication Date: 2017-03-21
    Description: This paper evaluates several techniques capable of mitigating the impact of low-power radio frequency jammers that interfere with ground-to-train communications. These radio communications are used for railway signaling, and interfering with these signals can have a negative impact on the train operation. Although the commercialization, detention, and use of radiofrequency jammers is strictly forbidden in most countries, they can be easily found on the internet at low cost and unexpectedly switched on by a passenger in a moving train. In this paper, we evaluate and compare the ground-to-train radio communication and intentional electromagnetic interference (IEMI) received signal powers delivered by roof train antennas to the train control command receiver. This comparison is used to deduce the potential zones of interference along the train trajectory and its consequences. Operating at the physical layer, we then propose and evaluate three mitigations techniques that can be used separately or combined to reduce the impact of this type of interference. We show that they can significantly reduce the jamming capability and help us in maintaining railway full operation.
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  • 29
    Publication Date: 2017-03-21
    Description: The evaluation of the ground admittance of an underground insulated conductor with a homogeneous nonmagnetic earth is of great significance when the electromagnetic compatibility is concerned. To evaluate the ground admittance efficiently, researchers proposed that the ground impedance of the conductor should be evaluated first and the ground admittance is related to the ground impedance through the wave number in the soil. There are several approximated analytical expressions for the evaluation of the ground impedance with a homogeneous earth and this fact makes the ground admittance easy to obtain. The characteristic of the approximated ground admittance evaluation approach is examined in this paper. Numerical examples illustrate that at frequencies with which the burial depth is much larger than the skin depth in the soil, the ground admittance and the ground impedance of the buried cable are well-related through the wave number in the soil. However, at other frequencies, the approximated approach fails to evaluate the ground admittance accurately. This paper also reveals that the discrepancy of the ground admittance will lead to a noticeable difference in the lightning induced voltage on buried cables.
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  • 30
    Publication Date: 2017-03-21
    Description: Cascade application of surge protective devices (SPDs) in low-voltage ac power circuits is intended to ensure proper equipment protection against surges as well as to provide surge energy distribution between SPDs. In order to evaluate equipment response and SPDs performance, concept of representative surges, which can be used for surge testing purposes, is introduced by international standards. Combination wave surge is defined both by IEEE C62.41.2 standard and IEC 61000-4-5 standard as one of the representative surges. However, these standards specify different tolerances regarding short-circuit current waveform's undershoot delivered by combination wave generator (CWG). The aim of this paper is to investigate the influences of different CWGs regarding short-circuit current undershoot in cascade two-stage protection system. It will be shown that differences that appear during surge testing with application of different CWGs can lead to inappropriate selection of SPDs regarding energy absorption capability and/or protection level.
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  • 31
    Publication Date: 2017-03-21
    Description: An inversion method for evaluating lightning current waveforms from measured electromagnetic field data based on time series neural network (TSNN) is presented in this paper. The back-propagation neural network (BPNN) is also adopted to evaluate the channel-base current using measured electromagnetic field data, and comparisons of inversion results between TSNN and BPNN are presented. The inversion results are in good agreement with corresponding measured channel-base currents. The proposed method can evaluate the channel-base current in areas with complex terrain, and it is useful for studies on lightning-protection in power systems and lightning characteristics
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  • 32
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    Publication Date: 2017-03-21
    Description: The Visible Infrared Imaging Radiometer Suite (VIIRS) instruments onboard both the Suomi National Polar-orbiting Partnership (S-NPP) and the first Joint Polar Satellite System (JPSS-1) spacecraft, with launch dates of October 2011 and late 2016, respectively, have polarization sensitivity, which affects the at-aperture radiometric calibration. This polarization sensitivity is caused by optics within VIIRS having different reflectance and transmission values as a function of at-aperture photon electric field orientation and is spectrally, spatially, and scan angle dependent. Characterization of the instrument’s polarization sensitivity for each visible near-infrared (VNIR) band and detector was performed prelaunch at multiple cross-track scan angles. The resultant characterization parameters are VIIRS polarization amplitude and phase that enable the at-aperture radiance to be adjusted based on its polarization characteristics. The sensor requirements are that the polarization amplitude for scan angles within ±45° of nadir be below 2.5%–3% depending on the band and have an uncertainty in both amplitude and phase of less than 0.5%. The S-NPP VIIRS passed these requirements with band M1 (412 nm) having the smallest margin (~8%). Modification to the VNIR bandpass filter designs on JPSS-1 was performed to reduce out-of-band response leaks observed prelaunch on S-NPP. An unintended consequence of the spectral bandpass modification was an increase in the polarization sensitivity by roughly a factor of 2 for some VNIR bands. The degree to which JPSS-1 VIIRS polarization sensitivity characterization results exceed the sensor specifications and comparisons with S-NPP will be discussed.
    Print ISSN: 0196-2892
    Electronic ISSN: 1558-0644
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  • 33
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  • 34
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
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  • 35
    Publication Date: 2017-03-21
    Description: Advanced interferometric synthetic aperture radar (InSAR) postprocessing, like persistent scatterer InSAR (PS-InSAR), offers the possibility to investigate slow moving landslides, where standard interferometry is problematic. These advanced algorithms involve the analysis of a series of SAR acquisitions in both time and space. One input that requires particular attention for landslide applications is the external digital elevation model (DEM) that is used to correct the interferograms for the topographic phase term. When multiple elevation data sets are available for a given study area, it is difficult to decide which one should be used. In this paper, we test the sensitivity of PS-InSAR/Small Baseline Subset (SBAS) results to different DEMs. The study area is located in the Northern Apennines of Italy, where chaotic clay shales and fine-grained flysch host slow-moving earth flows and ancient rock slides. $C$ -band (Envisat) and $X$ -band (Cosmo-SkyMed) data are processed with different DEMs. We describe a simple framework to statistically analyze the influence of these models on the final PS-InSAR/SBAS results. We find that individual interferograms do not vary much depending on the DEM, while the results from PS-InSAR and SBAS analysis do vary. This is likely caused by the way the DEM error is estimated. We find also that the quality of the DEM is more important than the resolution and that $X$ -band InSAR data are more sensitive to the choice of the DEM than $C$ -band. The significance of the results is discussed with reference to two landslide areas.
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  • 36
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: A very compact and conformal launcher for single conductor transmission lines (SCTLs) at the HF-band is presented. Also the concept of using drill pipes as the conductor of SCTL is introduced for the first time to satisfy the need for cost-effective and real-time data communication in drilling process. It is shown that a TM surface wave can be launched effectively making use of the drilling mud around the drill pipe. Provision of TM surface wave launchers that can fit within the borehole at both ends makes it feasible to transmit data over the drill pipe from downhole to the surface and vice versa. The launcher is composed of an open ended helical conductor which concentrically surrounds the drill pipe with appropriate pitch and length forming a compact surface wave launcher. Keeping its dimension smaller than $0.005lambda times 0.005lambda times 0.03lambda $ , the proposed launcher provides 2% fractional bandwidth at low HF-band.
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  • 37
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: In this paper, we study self-taught learning for hyperspectral image (HSI) classification. Supervised deep learning methods are currently state of the art for many machine learning problems, but these methods require large quantities of labeled data to be effective. Unfortunately, existing labeled HSI benchmarks are too small to directly train a deep supervised network. Alternatively, we used self-taught learning, which is an unsupervised method to learn feature extracting frameworks from unlabeled hyperspectral imagery. These models learn how to extract generalizable features by training on sufficiently large quantities of unlabeled data that are distinct from the target data set. Once trained, these models can extract features from smaller labeled target data sets. We studied two self-taught learning frameworks for HSI classification. The first is a shallow approach that uses independent component analysis and the second is a three-layer stacked convolutional autoencoder. Our models are applied to the Indian Pines, Salinas Valley, and Pavia University data sets, which were captured by two separate sensors at different altitudes. Despite large variation in scene type, our algorithms achieve state-of-the-art results across all the three data sets.
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  • 38
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: The analysis and correction of the bias occurring in weather radar polarimetric measurements is a challenging problem. Polarization coupling due to the cross-polar radiation pattern of the radar’s antenna is known to be responsible for errors in the estimation of the polarimetric covariance matrix, and consequently in the hydrometeor classification and quantification, either when using the ATSR or the SHV method. An alternative method for Doppler and polarimetric measurements based on transmitting three different polarizations (3-PolD) has been proven to provide accurate polarimetric covariance matrix estimates without making any hypothesis about the target polarimetric response or its Doppler spectrum. This method does not reduce the Doppler capabilities or the unambiguous range of the radar despite alternately transmitting 3-PolD. These characteristics have encouraged evaluating the polarimetric parameter biases due to cross-polar radiation when this method is used. Biases are calculated considering reflector antenna systems as well as phased-array antenna systems. The results show that this method may guarantee a tolerable bias level even with a poor co- to cross-polar antenna pattern ratio.
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  • 39
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: In a borehole radar (BHR) survey, a steel cable or a metallic drill pipe attached to a BHR can act as a waveguide, and often gives measured radargrams with strong, obliquely striped events. These guided BHR wave events are commonly considered as interference noise for conventional BHR surveys and have not been fully investigated. To better understand these events, a 2-D cylindrical finite-difference time-domain method is used in this paper for simulation and investigation of the guided BHR wave propagation. Snapshots of wavefields and response profiles for different configurations are simulated and analyzed to understand the generation and interaction process of the guided waves with the borehole and the surrounding formation. The simulation results confirm that if a conventional BHR is attached with a conductive waveguide, the BHR wave can be coupled with the waveguide to generate guided BHR waves propagating along the borehole. The backward-looking or forward-looking guided BHR reflections from the strata discontinuities are recorded on BHR profiles. The generation of forward-looking events makes it feasible to image ahead of a drill bit in real time while drilling using a conventional BHR. A simple formula to estimate the location of the interface using the forward-looking events is given. Based on the synthetic data with a BHR 3–7 m away from the interface, it was demonstrated that the location of the interface can be accurately predicted with an error of about 1 cm. Finally, the effect of the length of the waveguide on the guided waves is also discussed.
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  • 40
    Publication Date: 2017-03-21
    Description: Various polarimetric decomposition techniques have been proposed and demonstrated for more than 20 years. However, they still have never been operational applications because of insufficient validations. The true composition ratio of scattering mechanisms within a radar backscatter has to be known. To achieve this, a novel comprehensive approach to accurately identify the contribution of each scattering mechanism by a multiincidence angle and multipolarimetric (MIMP) synthetic aperture radar (SAR) observation combined with a theoretical model simulation is introduced. Rice paddies in Niigata City in Japan having a simple vegetation structure without topography were observed by X-band polarimetric and interferometric SAR 2 (Pi-SAR2), by gradually varying the flight path in terms of incidence angle. In addition to the MIMP SAR observation, a dominant scattering mechanism is reliably isolated through the theoretical characterization of the data by a discrete scatterer model. In the case of the rice paddies at a late vegetative stage, a dominant scattering on HH gradually varies from the double-bounce scattering to the volume scattering of rice grains in terms of incidence angle, whereas VV is affected by various volume scatterings of grains, leaves, and stems at the small, medium, and large incidence angles, respectively. HV is simply affected by the volume scattering of grains at the small incidence angle, and then it gradually switches to the volume scattering of the stalks. This brand new approach by the MIMP SAR observation with the theoretical modeling for this specific stage could take forward the polarimetric decomposition studies.
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  • 41
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: Advanced Land Observing Satellite-2 (ALOS-2) is designed to routinely acquire both scanning synthetic aperture radar (ScanSAR) and stripmap data. In this paper, we present a special multiband bandpass filter (MBF) to remove azimuth nonoverlap spectra for the interferometric processing of ALOS-2 full-aperture ScanSAR product. As required by the MBF, we estimate the important ScanSAR system parameters and the start times of raw bursts using ALOS-2 full-aperture ScanSAR image. The resulting MBF can remove the nonoverlap spectra caused by both Doppler centroid frequency difference and burst misalignment. It can be used in ScanSAR–ScanSAR interferometry, as well as ScanSAR–stripmap interferometry. Based on the MBF, we propose a single processing workflow that is able to implement both ScanSAR–ScanSAR interferometry and ScanSAR–stripmap interferometry. Finally, we present example interferograms of the 2015 Gorkha earthquake in Nepal processed using the proposed processing workflow. The interferograms are greatly improved after applying the MBF to remove the significant amount of nonoverlap spectra in the data.
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  • 42
    Publication Date: 2017-03-21
    Description: Terrestrial laser scanning (TLS) data provide 3-D measurements of vegetation structure and have the potential to support the calibration and validation of satellite and airborne sensors. The increasing range of different commercial and scientific TLS instruments holds challenges for data and instrument interoperability. Using data from various TLS sources will be critical to upscale study areas or compare data. In this paper, we provide a general framework to compare the interoperability of TLS instruments. We compare three TLS instruments that are the same make and model, the RIEGL VZ-400. We compare the range accuracy and evaluate the manufacturer’s radiometric calibration for the uncalibrated return intensities. Our results show that the range accuracy between instruments is comparable and within the manufacturer’s specifications. This means that the spatial XYZ data of different instruments can be combined into a single data set. Our findings demonstrate that radiometric calibration is instrument specific and needs to be carried out for each instrument individually before including reflectance information in TLS analysis. We show that the residuals between the calibrated reflectance panels and the apparent reflectance measured by the instrument are greatest for highest reflectance panels (residuals ranging from 0.058 to 0.312).
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  • 43
    Publication Date: 2017-03-21
    Description: The fusion of hyperspectral imaging (HSI) sensor and airborne lidar scanner (ALS) data provides promising potential for applications in environmental sciences. Standard fusion approaches use reflectance information from the HSI and distance measurements from the ALS to increase data dimensionality and geometric accuracy. However, the potential for data fusion based on the respective intensity information of the complementary active and passive sensor systems is high and not yet fully exploited. Here, an approach for the rigorous illumination correction of HSI data, based on the radiometric cross-calibrated return intensity information of ALS data, is presented. The cross calibration utilizes a ray tracing-based fusion of both sensor measurements by intersecting their particular beam shapes. The developed method is capable of compensating for the drawbacks of passive HSI systems, such as cast and cloud shadowing effects, illumination changes over time, across track illumination, and partly anisotropy effects. During processing, spatial and temporal differences in illumination patterns are detected and corrected over the entire HSI wavelength domain. The improvement in the classification accuracy of urban and vegetation surfaces demonstrates the benefit and potential of the proposed HSI illumination correction. The presented approach is the first step toward the rigorous in-flight fusion of passive and active system characteristics, enabling new capabilities for a variety of applications.
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  • 44
    Publication Date: 2017-03-21
    Description: In this paper, the development of a polarimetric phased array weather radar, which consists of a dual-polarized antenna with 2-D circular planar phase-array elements, is discussed. The radar is capable of measuring the 3-D rainfall distribution in less than several tens of seconds. Digital beamforming (DBF) is an important component in the development process of the phased array radar. In this paper, precipitation radar signal simulations are performed taking into consideration radar concepts in order to discuss the estimation accuracy of polarimetric precipitation profiles (differential reflectivity, specific differential phase, and copolar correlation coefficient) with two DBF methods that are based on Fourier and minimum mean-square error (MMSE) methods. A comparison of the performance of the two methods indicates that MMSE is superior in accuracy because of the effect of a stable and a robust main lobe and adaptively suppressed side lobes. MMSE also provides precipitation measurements eliminating the directional dependence of a beam pattern for improving the accuracy of measurements. It is also shown that the estimated accuracies of the precipitation profiles are almost independent of the number of pulses.
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  • 45
    Publication Date: 2017-03-21
    Description: Future weather radar systems will need to provide rapid updates within a flexible multifunctional overall radar network. This naturally leads to the use of electronically scanned phased array antennas. However, the traditional multifaced planar antenna approaches suffer from having radiation patterns that are variant in both beam shape and polarization as a function of electronic scan angle; even with practically challenging angle-dependent polarization correction, this places limitations on how accurately weather can be measured. A cylindrical array with commutated beams, on the other hand, can theoretically provide patterns that are invariant with respect to azimuth scanning with very pure polarizations. This paper summarizes recent measurements of the cylindrical polarimetric phased array radar demonstrator, a system designed to explore the benefits and limitations of a cylindrical array approach to these future weather radar applications.
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  • 46
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: We analyze the methods for measuring azimuth deformation with the L-band Advanced Land Observing Satellite-2 (ALOS-2) scanning synthetic aperture radar (ScanSAR) interferometry. To implement the methods, we extract focused bursts from the ALOS-2 full-aperture product, which is the only product available for ScanSAR interferometry at present. The extracted bursts are properly processed to measure azimuth deformation using interferometric phase. We apply the range split-spectrum method to ScanSAR to estimate the differential ionospheric phase of the interferogram, and take the azimuth derivative of the differential ionospheric phase to mitigate the relative azimuth shift caused by ionosphere. For the first time, azimuth deformation of a large earthquake (April 25, 2015 Nepal earthquake) is nearly completely measured by the L-band ScanSAR interferometry with moderate precision. The result is validated by the azimuth deformation measured by incoherent cross correlation using a pair of high-resolution RADARSAT-2 images. In addition to the final azimuth deformation, we show the possibility of processing full-aperture ScanSAR product using a burst-by-burst approach to form regular interferograms. We also show the recent strong large-scale ionospheric effects on the L-band ALOS-2 ScanSAR interferograms. Other possible applications of this paper include measuring the movement of glaciers.
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  • 47
    Publication Date: 2017-03-21
    Description: Ice flow velocity is used to estimate ice mass changes in glaciers and is a significant indicator of the stability of the Antarctica ice sheet in global change studies. The existing regional Antarctica ice flow speed maps are usually derived from radar or optical satellite observations of modern satellites since the 1970s. This paper presents a new analytical photogrammetric method for estimating Antarctica ice flow velocity fields by using film-based stereo ARGON photographs collected in the 1960s. The key of the proposed innovative method is a parallax decomposition that separates the effect of the terrain relief from the ice flow motion. An innovative implementation strategy is developed by using a framework that involves key techniques of hierarchical stereo image matching, ice flow direction determination, parallax decomposition, and ice flow speed estimation. This method is applied in the Rayner glacier in eastern Antarctica by using two sets of ARGON images with a two-month interval in 1963. The produced digital terrain model and speed map achieved a ground position accuracy of 61 m and a speed accuracy of 70 m $text{a}^{-1}$ . A comparison with recent products from 2000 to 2010 shows no significant topographic changes in the study area. Furthermore, the speed around the grounding line remained at the same level, while the speed in the ice shelf front decreased by 73 m $text{a}^{-1}$ . The ice shelf front advanced by approximately 7 km over more than 40 years. Overall, the observation results indicate favorable conditions for the stability of the Rayner glacier-ice shelf system.
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  • 48
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: We present a new framework, called multisensor coupled spectral unmixing (MuCSUn), that solves unmixing problems involving a set of multisensor time-series spectral images in order to understand dynamic changes of the surface at a subpixel scale. The proposed methodology couples multiple unmixing problems based on regularization on graphs between the time-series data to obtain robust and stable unmixing solutions beyond data modalities due to different sensor characteristics and the effects of nonoptimal atmospheric correction. Atmospheric normalization and cross calibration of spectral response functions are integrated into the framework as a preprocessing step. The proposed methodology is quantitatively validated using a synthetic data set that includes seasonal and trend changes on the surface and the residuals of nonoptimal atmospheric correction. The experiments on the synthetic data set clearly demonstrate the efficacy of MuCSUn and the importance of the preprocessing step. We further apply our methodology to a real time-series data set composed of 11 Hyperion and 22 Landsat-8 images taken over Fukushima, Japan, from 2011 to 2015. The proposed methodology successfully obtains robust and stable unmixing results and clearly visualizes class-specific changes at a subpixel scale in the considered study area.
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  • 49
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Print ISSN: 1057-7149
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  • 50
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Print ISSN: 1057-7149
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  • 51
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Print ISSN: 1057-7149
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  • 52
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: This paper provides an overview of the surface waves investigation and monitoring (SWIM) instrument which will be one of the two payload instruments carried by China France Oceanography SATellite (CFOSAT) with a planned launch date in mid-2018. SWIM is a real aperture wave scatterometer operated at near-nadir incidence angles and dedicated to the measurement of directional spectra of ocean waves. The SWIM flight model is currently being assembled and tested, its performance is being assessed and its prototype data processing algorithm is being developed. The aim of this paper is to provide a complete overview on the motivations and scientific requirements of this mission, together with a description of the design and characteristics of the SWIM instrument, and the analysis of its expected performances based on a prelaunch study. An end-to-end simulator has been developed to evaluate the quality of the data products, thus allowing the overall performance of the instrument to be assessed. Simulations run with two subsets of full orbit subsets show that the performances of the instrument and the inversion algorithms will meet the scientific requirements for the mission.
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  • 53
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
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  • 54
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
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  • 55
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: A rigorous self-contained formulation for analyzing electromagnetic scattering by a grating of plasmonic nanorods (Ag) coupled to a magneto-optical slab is presented. Bi-substituted gadolinium iron garnet is considered as the magneto-optical material. We measured the dielectric permittivity of the iron garnet and utilized the experimental data in our analyses. The method uses the Lattice Sums technique combined with the generalized reflection matrix approach. Using the method, the spectral response in reflectance as well as near-field distributions at resonance wavelengths have been numerical studied. Special attention has been paid to the coupling mechanism between the plasmonic grating and the magneto-optical slab. Physical insight is given to the strong field enhancement inside the magneto-optical material due to coupling with the plasmonic grating. Generalization of the method to the multilayered sandwiched structures, where the metal layer supporting surface plasmons is in contact with a layer possessing magnetically induced anisotropy, is straightforward. Such a combination enables one to achieve a multifold increase in sensitivity when compared with a system having just one nonmagnetic metal layer.
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  • 56
    Publication Date: 2017-03-21
    Description: To obtain a more accurate hysteresis curve for large Nd-Fe–B sintered magnets with high coercivity ( $H_{{mathrm {cJ}}}$ ), we employed a superconducting magnet-based vibrating sample magnetometer (SCM-VSM), which is independent of the drift. The demagnetization curves around $H_{{mathrm {cJ}}}$ resulting from the SCM-VSM, the hysteresis graph (HG), and the pulsed-field (PF) magnetometer were compared. Attention was paid to the accurate correction of the demagnetizing field ( $H_{d}$ ) for the cylindrical samples using a magnetometric demagnetizing factor dependent on the aspect ratio ( $L/D$ ) and differential coefficient of the measured curve ( $dJ/dH_{{mathrm {ex}}}$ ), where $L$ , $D$ , $J$ , and $H_{{mathrm {ex}}}$ are the length and diameter of sample, magnetization, and applied field, respectively. The cylindrical samples used were kept at a $D$ of 10 mm and an $L$ of 7 and 14 mm. The hysteresis curves and magnetic properties obtained from the SCM-VSM method agreed very well with one another, except for the differential susceptibility ( $dJ/dH_{{mathrm {eff}}}$ ) near $H_{{mathrm {cJ}}}$ using different shapes (cylinders and sphere) and sizes of magnets, where $H_{{mathrm {eff}}}$ is the effective field. The squareness ratio ( $H_{k}$ / $H_{{mathrm {cJ}}}$ ) and $dJ/dH_{{mathrm {eff}}}$ near $H_{{mathrm {cJ}}}$ obtained from the SCM-VSM method were found to be superior to those obtained from the PF method, where $H_{k}$ is the knee field. For the sample with a higher $H_{{mathrm {cJ}}}$ ( $geq 2$ MA/m), the abnormality of $J$ on the demagnetization curve had direct effects upon $dJ/dH_{{mathrm {eff}}}$ near $H_{{mathrm {cJ}}}$ and $H_{k}$ / $H_{{mathrm {cJ}}}$ in the HG method. However, a larger $L/D$ has an effect on improving these values as has been previously found in this paper. For large magnets, the values of $dJ/dH_{{mathrm {eff}}}$ near $H_{{mathr
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  • 57
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: Force density calculus in permanent magnets and other nonlinear magnetic media is still a challenge despite two hundred years of electromagnetic theory. While generally accepted formulas to compute the total electromagnetic force on a domain exist in the literature, calculating the local distribution of forces that are needed, for instance, to couple electromagnetic and mechanical finite-element method simulations is a more open subject. In particular, it is widely believed that the contact force between magnetic materials touching each other cannot be properly estimated and the insertion of thin virtual air gaps is required. In this paper, first, the formulas existing in the bibliography to compute the resultant electromagnetic force and torque on a bounded domain are revisited and extended. The new formulas can be applied to cases where the boundary of the domain is a discontinuity surface for the magnetic field. In particular, they allow computing the force and torque on a magnet totally or partially embedded in a ferromagnetic material without using any artificial air layer between them. Then, these formulas are checked by using numerical simulation of suitable experiments.
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  • 58
    Publication Date: 2017-03-21
    Description: The literature discussing pulse-shape discrimination (PSD) in organic scintillators dates back several decades. However, little has been written about PSD techniques that are optimized for neutron spectrum unfolding. Variation in $n$ - $gamma $ misclassification rates and in $gamma /n$ ratio of incident fields can distort the neutron pulse-height response of scintillators and these distortions can in turn cause large errors in unfolded spectra. New applications in arms-control verification call for detection of lower-energy neutrons, for which PSD is particularly problematic. In this article, we propose techniques for removing distortions on pulse-height response that result from the merging of PSD distributions in the low-pulse-height region. These techniques take advantage of the repeatable shapes of PSD distributions that are governed by the counting statistics of scintillation-photon populations. We validate the proposed techniques using accelerator-based time-of-flight measurements and then demonstrate them by unfolding the Watt spectrum from measurement with a 252 Cf neutron source.
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  • 59
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    Publication Date: 2017-03-21
    Description: Axial flux resolvers (AFRs) are used in motion control of electrical machines. In this paper, the effects of physical parameters on the accuracy of detected position are studied. The examined parameters are width of slot opening and slot width, number of poles, number of slots per pole and per phase, and skewing of rotor slots. An analytical model based on the winding function method is proposed for the first time in to estimate the error of position signal. The results of the analytical method are verified with 3-D time stepping finite-element method. Finally, the prototype of the studied AFR is constructed and tested. Good agreement between simulation and experimental results confirms the effectiveness of the proposed analytical model.
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  • 60
    Publication Date: 2017-03-21
    Description: A discretized positioning circuit (DPC) based on a resistive network has been developed to reduce the size of a gamma-ray detection system using multi-anode photomultiplier tubes (MA-PMT) in an array, because it can drastically decrease the number of output channels. The output signal from the gamma-ray detection system is a current pulse generated in each tube that contains information about the gamma-ray energy and detecting position in the array. The output current pulse is distributed to four outputs according to the resistance ratio of the resistive network in the DPC, and the detected position is estimated using the height values of the four distributed current pulses. However, owing to parasitic capacitors of MA-PMT connected in parallel to resistors in the resistive network, the four output pulses are affected by the RC time constants. In particular, when the duration of the input signal is not long enough, the height values of the distributed pulses are reduced, and thereby the position error increases significantly. In this paper, we present a new distortion correction method that considers the pulse duration and the RC time constant. In order to correct the position error, we employed homography, which is a coordinate transformation method. The ideal grid was mapped to a new grid for the distorted position. Using this method, error correction was completely achieved, even for short current pulses.
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  • 61
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    Publication Date: 2017-03-21
    Description: There has been increased interest in organic semiconductors over the last decade because of their unique properties. Of these, 5, 6, 11, 12-tetraphenylnaphthacene (rubrene) has generated the most interest because of its high charge carrier mobility. In this work, large single crystals with a volume of ~1 cm 3 were grown from solution by a temperature reduction technique. The faceted crystals had flat surfaces and cm-scale, visually defect-free areas suitable for physical characterization. X-ray diffraction analysis indicates that solvent does not incorporate into the crystals and photoluminescence spectra are consistent with pristine, high-crystallinity rubrene. Furthermore, the response curve to pulsed optical illumination indicates that the solution grown crystals are of similar quality to those grown by physical vapor transport, albeit larger. The good quality of these crystals in combination with the improvement of electrical contacts by application of conductive polymer on the graphite electrodes have led to the clear observation of alpha particles with these rubrene detectors. Preliminary results with a 252 Cf source generate a small signal with the rubrene detector and may demonstrate that rubrene can also be used for detecting high-energy neutrons.
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  • 62
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: The conventional front-end electronics for PET imaging consist of an energy circuit and a timing circuit. A single channel in front-end electronics typically requires several amplifiers, an ADC and a TDC. In this paper, we present a novel front-end electronic design using 1-bit sigma-delta ( $boldsymbol {Sigma }$ - $boldsymbol {Delta }$ ) modulation and an FPGA. The new design requires only one analog amplifier per channel. The output of the analog amplifier is read directly by the FPGA. Both the energy and timing calculation are implemented in FPGA firmware. The scope of this paper is to introduce the novel design in detail and to evaluate its performance in energy and dark current measurements. Simulink simulations were performed to validate the design with ideal components. A one-channel prototype circuit was built to assess the design with real components. The prototype circuit was tested with different input signals, including test pulses, pulse signals from a PMT detector, DC current signals and dark current signals from an SiPM sensor. Both the simulation and experimental results show that the method is inherently stable and has excellent accuracy and linearity in energy and dark current measurements. The prototype analog board was built with discrete components cost about $ 0.5 in total. The power consumption was about 20 mW. We conclude that the new method provides a cost-efficient and power-efficient way to accurately measure the energies of analog pulses and dark currents from detectors. The timing performance of this method is currently under evaluation.
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  • 63
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-03-21
    Description: This paper presents a new power systems simulation environment suitable for the swift calculation of the periodic steady-state response of large power networks with large wind parks. In order to achieve the greatest computational efficiency and solution reliability, the wind generator model uses the state-of-the-art voltage-behind-reactance model of the induction generator; in this first part of the paper, the fixed-speed wind generator model is presented. The overall solving environment for the nonlinear system of differential equations representing the power system is the so-called Poincaré map method. A rather useful feature to reduce further the calculation times is the availability of an equivalent wind farm model based on multiple wakes. The Poincaré acceleration yields a vastly improved numerical solution compared to existing models of fixed-speed wind parks. The application of equivalent wind farm models yields a staggering reduction in the elapsed time to only 1.16% of the time demanded by the detailed model, while retaining a good approximation of the response of the wind farm. Full comparisons of the detailed and equivalent wind park models with PSCAD/EMTDC, are carried out and the agreement of the results is excellent. In this paper the emphasis is on harmonic generation.
    Print ISSN: 1949-3029
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  • 64
    Publication Date: 2017-03-21
    Description: In wind farms (WF), the most popular and commonly implemented active power control method is the maximum power point tracking (MPPT). Due to the wake effect, the upstream wind turbine (WT) in WFs has more active power generation than the downstream WT at the wind directions and wind speeds that the WF has wake loss. In the case that WTs support the voltage control by reactive power, the upstream WT's power converter may have shorter lifetime even below the industrial standard. In this paper, based on the analysis of the wake effect, the reactive power capability of the doubly fed induction generator (DFIG) WT, and the lifetime of the DFIG WT's power converter, a reactive power dispatch method is proposed in the WF with DFIG WTs to improve the lifetime of the upstream WT's power converter. The proposed reactive power dispatch method is analyzed and demonstrated by the simulation on a WF with 80 DFIG WTs. It can be concluded that, compared with the traditional reactive power dispatch method, the proposed method can increase the lifetime of the upstream WT's power converter.
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    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 65
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    Publication Date: 2017-03-21
    Description: Many countries have set challenging wind power targets to achieve by 2020. This paper implements a realistic analysis of curtailment and constraint of wind energy at a nodal level using a unit commitment and economic dispatch model of the Irish Single Electricity Market in 2020. The key findings show that significant reduction in curtailment can be achieved when the system nonsynchronous penetration limit increases from 65% to 75%. For the period analyzed, this results in a decreased total generation cost and a reduction in the dispatch-down of wind. However, some nodes experience significant dispatch-down of wind, which can be in the order of 40%. This work illustrates the importance of implementing analysis at the nodal level for the purpose of power system planning.
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    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 66
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    Publication Date: 2017-02-11
    Description: Numerical and experimental sensitivity analyses in this paper indicate that the accuracy of a silicon multi-element piezoresistive (PR) stress sensor can be dramatically influenced by the microfabrication non-uniformity and the uncertainties in the values of the PR coefficients and the thermal coefficient of resistance (TCR). The results showed that errors as large as 70% FS or more, in the extracted stress values, may be obtained due to uncertainty of about 2.5% in the values of PR coefficients. This paper aims to evaluate the capabilities of the artificial neural network (ANN) to eliminate the error in stress measurement, due to the fabrication non-uniformity within wafer, wafer-to-wafer, and batch-to-batch, for multi-element PR sensing rosettes. In this paper, sensing chips from two different batches were integrated in building the ANN and testing its performance. The proposed calibration technique employs the neural network fitting Toolbox in MATLAB to generate a two-layer feed-forward network, with sigmoid hidden neurons and linear output neurons. Three different configurations of calibration were designed to test the generalization abilities of the ANN in capturing the in-plane stress components exerted on the silicon chip. The results showed that ANN is capable of accurately predicting the stresses applied to the sensing chip with maximum stress error of 1.5% FS with no need for individual, expensive, and time-consuming calibration process for each sensor.
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  • 67
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-02-11
    Description: The search for a mobile target is a dynamic spatial and temporal problem. Information gathered during the search, regarding the potential whereabouts of the target, can be used to influence significantly the search strategy employed. In this paper, thus, a novel (wireless) static-sensor network deployment strategy is presented to detect efficiently and effectively a mobile target in an unbounded environment. The proposed strategy deploys the static sensors optimally and in a time-phased manner while adapting in real-time to the availability of new information during the search. An optimal network-deployment plan, herein, refers to a set of optimal sensor-deployment times and locations. The optimal sensor-deployment instances aim to achieve a uniform deployment of search effort over time. Optimal sensor-deployment locations, in turn, are determined according to the highest possible likelihood of detection of the mobile target. The proposed deployment strategy contains two novel contributions: it makes use of a non-parametric approach to estimate effectively the target location likelihood, and it performs an optimization of sensor-placement times to maximize the adaptive characteristic of the deployment plan. Several detailed experiments (in virtual and physical environments) of the proposed strategy for static-sensor network deployment in wilderness search and rescue applications are presented. Furthermore, a comparative study is included to highlight the advantages of our approach versus traditional methods that deploy sensors simultaneously for uniform coverage.
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  • 68
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-02-11
    Description: This paper introduces a novel multi-classification technique, which improves two conflicting main objectives of classification problems, i.e., classification accuracy and worst case sensitivity. Global performance measures such as overall accuracy might not be enough to evaluate classifiers and alternative measurements are essentially required. This paper addresses a new model selection problem to construct a tree-based hierarchical classification model based on ensemble of six different classifiers. In our proposed approach, the model selection is tackled as a multi-objective optimization, which not only considers the accuracy of the classification, but also tries to maximize the worst case sensitivity of the multi-class problem. The proposed technique is applied on nine different classes corresponding to various breathing disorders for designing a wearable remote monitoring system. This model correctly classified the respiratory patterns of ten subjects with an accuracy of 99.25% and a sensitivity of 97.78% with detecting the changes in the anterior-posterior diameter of the chest wall during breathing function by means of two accelerometer sensors worn on subject’s rib cage and abdomen. The effects of the number of sensors, sensor placement, as well as feature selection on the classification performance are also discussed.
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  • 69
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    Publication Date: 2017-02-11
    Description: Activity recognition through ambient sensors in a smart home can efficiently monitor residents’ abnormal behaviors in daily life, while not adding extra burdens caused by wearable sensors. Monitoring and separating the activities of a specific individual in a multi-residential home is still, however, a significant challenge for these smart home applications. This paper proposes a new human identification sensor, which can efficiently differentiate multiple residents in a home environment to detect their height as a unique bio-feature. This sensor includes three sensing/communication modules: pyroelectric infrared (PIR) occupancy, ultrasound array, and bluetooth low energy (BLE) communication modules. The PIR occupancy module is used to detect the moving direction, while the ultrasound array module detects the moving residents’ height. The combination of these two sensing technologies can be used to then detect the moving velocity. The BLE advertising mode is then used to communicate these data to the data server. A new embedded algorithm increased the energy efficiency of this identification technology. A comprehensive modeling and experiments are done to assess the performance of this sensor and the results are provided.
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  • 70
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    Publication Date: 2017-02-11
    Description: Deadline constrained packet scheduling and transmission are important in real-time multimedia applications. This is because packets missing their deadlines would become useless and are frequently dropped, which seriously degrade the quality of service (QoS). As the utilization of Internet of Things has become mature, multimedia data transmission is a key component to promote the QoS of citizens. To fulfill the QoS requirement in wireless sensor networks (WSNs) with multimedia content, the combination of multiple transmission methods is encouraged for packet forwarding, including conventional network coding, analog network coding, plain routing, and direct transmission (i.e., no-relaying, NR). The diversity of transmission method is helpful to lower packet dropping probability, while complicating the packet transmitting and scheduling process instead. Therefore, we first introduce an exhaustive search method to obtain the optimal scheduling sequence and corresponding transmission method for deadline constrained multimedia transmissions in WSNs. With the objective of promoting computing efficiency for the formulated problem, we then propose two heuristic methods based on the Markov chain approximation and the dynamic graph, respectively. Simulation results illustrate that our methods can effectively reduce packet dropping probability and simulation time, so that QoS of individuals can be promoted.
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  • 71
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    Publication Date: 2017-02-11
    Description: This paper presents a study in order to identify the value range of the main parameters within carrier sense multiple access (CSMA) defined in IEEE 802.15.4 that guarantees a satisfactory wireless sensor network (WSN) performance for a volcano monitoring application. Moreover, this study performs the comparison among several test-beds in outdoor scenarios with the purpose of distinguishing the optimal number of nodes for each gateway according the main constraints given by an existing sensor network for real-time (RT) volcano monitoring system such as sampling time, packet loss, and delay. We used a mathematical model that works with Markovian techniques and involves some parameters of CSMA mechanism within the model, such as the minimum value of the backoff exponent (BEmin), the contention window length (W), and the number of slots (L). We obtained the approximate values of these parameters by the interpolation of the normalized throughput curves from the deployment, and thus, we could obtain a mathematical model with the specifications required for the RT volcano monitoring. After validating the model with test-bed outdoor deployments we found that BEmin, W and L are key factors for determining the performance of a WSN, these parameters guarantee the range in which the WSN works according to the constraints imposed for this particular volcano monitoring application.
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  • 72
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    Publication Date: 2017-02-11
    Description: In this paper, we propose a joint throughput and time-resource allocation scheme for the virtualization of IEEE 802.15.4-based wireless sensor networks (WSNs). Virtualization is realized through utilization of the guaranteed time slot (GTS) mechanism of cluster-tree topology to schedule resources on a media access control (MAC) layer. We develop a scheduler that is located in the personal area network (PAN) coordinator and that virtualizes the network into an aggregate of independent profiles, assigning the available resources to each profile with end-to-end (ETE) delay guarantees. The scheduler solves the problem of managing resources available in the network in an optimization framework, taking into consideration the individual profile and sensor requirements. Moreover, it uses the proposed heuristic fair resource allocation (FRA) algorithm to derive the solution in polynomial time. We validate the scheduling performance via discrete event simulation (DES) and compare the proposed FRA algorithm with round robin (RR) and proportionally fair (PF) scheduling algorithms in several scenarios. The proposed scheme demonstrates efficient resource management while maintaining profile isolation in all cases, whereas other algorithms lead to increased latency and lower throughput in the network.
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  • 73
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-02-11
    Description: Radiometer calibration using a compensation method based on temperature drift under a variety of environmental conditions can be used for airborne applications because of limitations on weight and power. Accordingly, the observation of the variation of the system states via analysis of the obtained response with temperature data is necessary to compensate the fluctuation of physical temperature for accurate calibration of the radiometer. However, the accuracy of the previous method (which uses one or more temperature probe) can rarely obtain an accurate estimated result; its accuracy is insufficient for high-precision measurement applications. Additionally, previous methods may cause unpredictable estimation errors when using regression methods with fewer measurable sensors. Therefore, more advanced compensation methods, which can compensate for the drift in radiometer output using temperature sensors (based on the analysis of the distinctive features of the temperature), are required to estimate the brightness temperature. In this paper, an optimized thermal compensation method using a selection of the optimal point for gain and offset probing to control the coefficients is analyzed using both the correlation-matrix-based hierarchical clustering and a comparison with the response stability for the training period. Then, the clustered temperature sensors of the radiometer system are used in the predictor variable to achieve optimum compensation of radiometer response variation. Next, the regression model of the multiple linear clustering method is compared the estimation accuracy for the selected training period and temperature sensors. Improved results relative to the reference method are achieved using the proposed model in experiments.
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  • 74
    Publication Date: 2017-02-11
    Description: The key issue in image fusion is the process of defining evaluation indices for the output image and for multi-scale image data set. This paper attempted to develop a fusion model for plantar pressure distribution images, which is expected to contribute to feature points construction based on shoe-last surface generation and modification. First, the time series plantar pressure distribution image was preprocessed, including back removing and Laplacian of Gaussian (LoG) filter. Then, discrete wavelet transform and a multi-scale pixel conversion fusion operating using a parameter estimation optimized Gaussian mixture model (PEO-GMM) were performed. The output image was used in a fuzzy weighted evaluation system, that included the following evaluation indices: mean, standard deviation, entropy, average gradient, and spatial frequency; the difference with the reference image, including the root mean square error, signal to noise ratio (SNR), and the peak SNR; and the difference with source image including the cross entropy, joint entropy, mutual information, deviation index, correlation coefficient, and the degree of distortion. These parameters were used to evaluate the results of the comprehensive evaluation value for the synthesized image. The image reflected the fusion of plantar pressure distribution using the proposed method compared with other fusion methods, such as up-down, mean-mean, and max-min fusion. The experimental results showed that the proposed LoG filtering with PEO-GMM fusion operator outperformed other methods.
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  • 75
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    Publication Date: 2017-02-11
    Description: Presents the guidelines for the IEEE Sensors Journal Frontpiece competition.
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  • 76
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    Publication Date: 2017-02-11
    Description: Monitoring physiological signs in animal testing is crucial for the development of new therapeutic strategies and better understanding of diseases. This paper exploits Doppler radar and nonlinear phase demodulation effect to achieve noncontact measurement of both displacements and frequencies of a laboratory rat’s cardiorespiratory activities. The implementation of displacement acquisition method relying on demodulation-generated harmonics is described, and this paper provides a guideline of implementing the acquisition method. Demodulation-generated harmonics are analyzed, and the effect of vibration-generated harmonics is studied. To demonstrate the effectiveness, a 60-GHz radar is used that shows good correlation with the instrument-recorded data. Average errors of respiration rate and heart rate (HR) are 0.057% and 0.33%, respectively, using three test subjects. In addition, two drug tests are performed to verify the monitoring function with controlled raised/dropped HR. By observing the time periods before, during, and after drug injection, results of rat’s physiological response to drugs reveal the drug efficacy and body reaction over time. The measured cardiorespiratory variations can provide useful information without using implant devices, and the implementation could be an improvement over current invasive methods. The result presented in this paper is believed to be the first reported simultaneous measurements of both frequencies and displacements of both respiration and heartbeat movements of a laboratory animal using microwave radar.
    Print ISSN: 0018-9480
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  • 77
    Publication Date: 2017-02-11
    Description: Noncontact physiological monitoring using Doppler radar has been studied extensively. Most commonly, continuous-wave (CW) quadrature Doppler radar is used to measure cardiopulmonary rates. Accurate displacement measurement can provide physiological waveform recovery, which may enable tidal volume and pulse pressure estimation. In this paper, we propose a calibration technique that enables high-accuracy millimeter-order periodic displacement measurements using CW quadrature Doppler radar. Theoretical analysis of center estimation error and its propagation effect are presented. Simulations are performed to show how noise and limited arc length affect error and affect the accuracy of center estimation, as well as improvements after calibration. A high-precision linear stage was employed to create periodic motion for evaluating the performance of calibration technique. Experimental results demonstrate that the proposed calibration technique enables displacement measurement with accuracy within tens of micrometers.
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  • 78
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    Publication Date: 2017-02-11
    Description: Spatial diversity cross-polar approach to fast electromagnetic imaging of millimeter-wave chipless radio-frequency identification (RFID) tags is proposed. Slow imaging in the synthetic aperture radar (SAR) technique due to the moving reader antenna is replaced by a stationary multiple-input multiple-output (MIMO) array antenna. The proposed MIMO technique requires a large number of antenna elements, which impedes practical implementation of the reader. An optimized MIMO system through a genetic algorithm halves the number of antenna elements and successfully replaces the conventional SAR. The optimized antenna system combines with the original spatial diversity approach to provide a low-cost solution for chipless RFID tagging with enhanced content capacity. The system successfully decodes a 60-GHz 17-b chipless tag in an area that is one fifth of a credit card. The tag can be printed with a low-resolution printer and read on metal and liquid containers.
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  • 79
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    Publication Date: 2017-02-11
    Description: Manifold learning and dimensionality reduction techniques are ubiquitous in science and engineering, but can be computationally expensive procedures when applied to large datasets or when similarities are expensive to compute. To date, little work has been done to investigate the tradeoff between computational resources and the quality of learned representations. We present both theoretical and experimental explorations of this question. In particular, we consider Laplacian eigenmaps embeddings based on a kernel matrix, and explore how the embeddings behave when this kernel matrix is corrupted by occlusion and noise. Our main theoretical result shows that under modest noise and occlusion assumptions, we can (with high probability) recover a good approximation to the Laplacian eigenmaps embedding based on the uncorrupted kernel matrix. Our results also show how regularization can aid this approximation. Experimentally, we explore the effects of noise and occlusion on Laplacian eigenmaps embeddings of two real-world datasets, one from speech processing and one from neuroscience, as well as a synthetic dataset.
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  • 80
    Publication Date: 2017-02-11
    Description: A novel method to generate frequency-multiplied and phase-coded microwave signals based on a polarization division multiplexing (PDM) dual-arm Mach–Zehnder modulator (DMZM) or a PDM dual-parallel MZM (DPMZM) is proposed. In the proposed scheme, the PDM-DMZM or PDM-DPMZM is employed to produce two orthogonally polarized wavelengths with a wavelength spacing that is two, four, or eight times of the driving frequency. Then the signal is sent into a polarization modulator-based microwave photonic phase coder for phase coding. A theoretical analysis and an experiment are carried out. Phase-coded signals with frequency multiplication factors of two, four and eight are successfully generated. The bandwidth of the system is discussed, and the impact of the polarization extinction ratio is also analyzed.
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  • 81
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    Publication Date: 2017-02-11
    Description: This paper is concerned with the problem of low-rank plus sparse matrix decomposition for big data. Conventional algorithms for matrix decomposition use the entire data to extract the low-rank and sparse components, and are based on optimization problems with complexity that scales with the dimension of the data, which limits their scalability. Furthermore, existing randomized approaches mostly rely on uniform random sampling, which is quite inefficient for many real world data matrices that exhibit additional structures (e.g., clustering). In this paper, a scalable subspace-pursuit approach that transforms the decomposition problem to a subspace learning problem is proposed. The decomposition is carried out by using a small data sketch formed from sampled columns/rows. Even when the data are sampled uniformly at random, it is shown that the sufficient number of sampled columns/rows is roughly $mathcal {O}(r mu)$ , where $mu$ is the coherency parameter and $r$ is the rank of the low-rank component. In addition, adaptive sampling algorithms are proposed to address the problem of columns/rows sampling from structured data. We provide an analysis of the proposed method with adaptive sampling and show that adaptive sampling makes the required number of sampled columns/rows invariant to the distribution of the data. The proposed approach is amenable to online implementation and an online scheme is proposed.
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  • 82
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    Publication Date: 2017-02-11
    Description: Numerous applied problems of two-dimensional (2-D) and 3-D imaging are formulated in continuous domain. They place great emphasis on obtaining and manipulating the Fourier transform in polar and spherical coordinates. However, the translation of continuum ideas with the discrete sampled data on a Cartesian grid is problematic. There exists no exact and fast solution to the problem of obtaining discrete Fourier transform for polar and spherical grids in the literature. In this paper, we develop exact algorithms to the above problem for 2-D and 3-D, which involve only 1-D equispaced fast Fourier transform with no interpolation or approximation at any stage. The result of the proposed approach leads to a fast solution with very high accuracy. We describe the computational procedure to obtain the solution in both 2-D and 3-D, which includes fast forward and inverse transforms. We find the nested multilevel matrix structure of the inverse process, and we propose a hybrid grid and use a preconditioned conjugate gradient method that exhibits a drastic improvement in the condition number.
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  • 83
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    Publication Date: 2017-02-11
    Description: Sparse recovery aims to reconstruct sparse signals from compressed linear measurements. In this paper, we propose a sparse recovery algorithm called multiple orthogonal least squares (MOLS), which extends the well-known orthogonal least squares (OLS) algorithm by allowing multiple $L$ indices to be selected per iteration. Owing to its ability to catch multiple support indices in each selection, MOLS often converges in fewer iterations and hence improves the computational efficiency over the conventional OLS algorithm. Theoretical analysis shows that MOLS ( $L > 1$ ) performs exact recovery of $K$ -sparse signals ( $K > 1$ ) in at most $K$ iterations, provided that the sensing matrix obeys the restricted isometry property with isometry constant $delta _{LK} 〈 {sqrt{L}}/({sqrt{K} + 2 sqrt{L}}).$ When $L = 1,$ MOLS reduces to the conventional OLS algorithm and our analysis shows that exact recovery is guaranteed under $delta_{K +1} 〈 1 / (sqrt{K} + 2)$ . This condition is nearly optimal with respect to $delta _{K+1}$ in the sense that, even with a small relaxation (e.g., $delta_{K + 1} = 1 / sqrt{K}$ ), exact recovery with OLS may not be guaranteed. The recovery performance of MOLS in the noisy sce- ario is also studied. It is shown that stable recovery of sparse signals can be achieved with the MOLS algorithm when the signal-to-noise ratio scales linearly with the sparsity level of input signals.
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  • 84
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    Publication Date: 2017-02-11
    Description: Many applications collect a large number of time series, for example, the financial data of companies quoted in a stock exchange, the health care data of all patients that visit the emergency room of a hospital, or the temperature sequences continuously measured by weather stations across the US. These data are often referred to as un structured. The first task in its analytics is to derive a low dimensional representation, a graph or discrete manifold, that describes well the inter relations among the time series and their intra relations across time. This paper presents a computationally tractable algorithm for estimating this graph that structures the data. The resulting graph is directed and weighted, possibly capturing causal relations, not just reciprocal correlations as in many existing approaches in the literature. A convergence analysis is carried out. The algorithm is demonstrated on random graph datasets and real network time series datasets, and its performance is compared to that of related methods. The adjacency matrices estimated with the new method are close to the true graph in the simulated data and consistent with prior physical knowledge in the real dataset tested.
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    Publication Date: 2017-02-11
    Description: In this paper, we present a novel technique for the retrieval of the modes of a multicomponent signal using a time-frequency (TF) representation of the signal. Our approach is based on a novel ridge extraction method that takes into account the fact that the TF representation is both discrete in time and frequency, followed by a demodulation procedure. Numerical results show the benefits of the proposed approach for mode reconstruction in comparison to similar techniques that do not make use of demodulation. Furthermore, numerical investigations show that the proposed approach sharpens the TF representation on which it is built.
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    Publication Date: 2017-02-11
    Description: A novel approach termed stochastic truncated amplitude flow (STAF) is developed to reconstruct an unknown $n$ -dimensional real-/complex-valued signal $boldsymbol {x}$ from $m$ “phaseless” quadratic equations of the form $psi _i=|langle boldsymbol {a}_i,boldsymbol {x}rangle |$ . This problem, also known as phase retrieval from magnitude-only information, is NP-hard in general. Adopting an amplitude-based nonconvex formulation, STAF leads to an iterative solver comprising two stages: s1) Orthogonality-promoting initialization through a stochastic variance reduced gradient algorithm; and, s2) a series of iterative refinements of the initialization using stochastic truncated gradient iterations. Both stages involve a single equation per iteration, thus rendering STAF a simple, scalable, and fast approach amenable to large-scale implementations that are useful when $n$ is large. When $lbrace boldsymbol {a}_irbrace _{i=1}^m$ are independent Gaussian, STAF provably recovers exactly any $boldsymbol {x}in mathbb{R}^n$ exponentially fast based on order of $n$ quadratic equations. STAF is also robust in the presence of additive noise of bounded support. Simulated tests involving real Gaussian $lbrace boldsymbol {a}_irbrace$ vectors demonstrate th- t STAF empirically reconstructs any $boldsymbol {x}in mathbb{R}^n$ exactly from about $2.3n$ magnitude-only measurements, outperforming state-of-the-art approaches and narrowing the gap from the information-theoretic number of equations $m=2n-1$ . Extensive experiments using synthetic data and real images corroborate markedly improved performance of STAF over existing alternatives.
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    Publication Date: 2017-02-11
    Description: We consider a distributed parameter estimation problem, in which multiple terminals send messages related to their local observations using limited rates to a fusion center which obtains an estimate of a parameter related to the observations of all terminals. It is well known that if the transmission rates are in the Slepian–Wolf region, the fusion center can fully recover all observations and hence can construct an estimator having the same performance as that of the centralized case. One natural question is whether Slepian–Wolf rates are necessary to achieve the same estimation performance as that of the centralized case. In this paper, we show that the answer to this question is negative. We establish our result by explicitly constructing an asymptotically minimum variance unbiased estimator that has the same performance as that of the optimal estimator in the centralized case while using information rates less than the conditions required in the Slepian–Wolf rate region. The key idea is that, instead of aiming to recover the observations at the fusion center, we design universal schemes enabling the fusion center to compute a sufficient statistic using rates outside of the Selpian–Wolf region.
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  • 88
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    Publication Date: 2017-02-11
    Description: We propose two computationally efficient residual Doppler shift estimation methods for underwater acoustic multicarrier communication. The first method is based on computing the phase of the root of a low order polynomial. The second method is a closed-form least squares estimate given the unwrapped phases of the minimal eigenvector of a small data matrix. The complexities of both estimates are significantly lower compared to the methods commonly used in underwater acoustic multicarrier communication, which result in nonlinear least squares estimators and thus require a fine grid search in the frequency domain. Numerical simulations show that the mean square errors of the proposed methods have similar performance as the common estimation techniques, achieve the Cramer–Rao lower bounds at low noise levels, and agree with their theoretically derived variances. Pool experiments and sea trial results further demonstrate that the suggested estimates yield similar results as the common nonlinear least squares estimates but at a lower complexity.
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-02-11
    Description: When the noise affecting time series is colored with unknown statistics, a difficulty for sinusoid detection is to control the true significance level of the test outcome. This paper investigates the possibility of using training datasets of the noise to improve this control. Specifically, we analyze the performances of various detectors applied to periodograms standardized using training datasets. Emphasis is put on sparse detection in the Fourier domain and on the limitation posed by the necessarily finite size of the training sets available in practice. We study the resulting false alarm and detection rates and show that standardization leads, in some cases, to powerful constant false alarm rate tests. The study is both analytical and numerical. Although analytical results are derived in an asymptotic regime, numerical results show that theory accurately describes the tests’ behavior for moderately large sample sizes. Throughout the paper, an application of the considered periodogram standardization is presented for exoplanet detection in radial velocity data.
    Print ISSN: 1053-587X
    Electronic ISSN: 1941-0476
    Topics: Electrical Engineering, Measurement and Control Technology
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  • 90
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-08-12
    Description: High-speed photodiodes are a key element of numerous photonic systems. With the development of potential applications in the THz range such as sensing, spectroscopy, and wireless transmission, devices with integrated antenna covering the frequency range from 0.1 to 3 THz will become essential. In this paper, we discuss the development of uni-traveling carrier photodiodes with integrated antennas to address that need. In particular we develop the key elements to present a simple design tool for the efficient integration of the device with an antenna. We also present fabricated device results that show the highest figure of merit to date for photonic THz emitters. When integrated with well-matched antennas the devices have achieved record level of power up to 1 THz compared to other published photomixers. We also show that these devices can be used as receivers at frequencies up to 560 GHz with conversion losses of the order of 30 dB.
    Print ISSN: 1077-260X
    Electronic ISSN: 1558-4542
    Topics: Electrical Engineering, Measurement and Control Technology
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  • 91
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-08-12
    Description: Presents the table of contents for this issue of the publication.
    Print ISSN: 1527-3342
    Electronic ISSN: 1557-9581
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  • 92
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-08-12
    Description: Presents the introductory editorial for this issue of the publication.
    Print ISSN: 1527-3342
    Electronic ISSN: 1557-9581
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  • 93
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-08-12
    Description: This paper describes an implementation of a preprocessor with a perceptron for applications in amperometry. The perceptron operates in the current mode, in the weak-inversion area and makes it possible to process analog current signals with values below 1 nA. This paper presents an axon structure consisting of six transistors and a programmable dendrite with a fully digital interface implementing weights with an accuracy of 0.13%. The perceptron implemented in the 65-nm CMOS technology is characterized by a power consumption of 2.5 nW per channel. The data processing frequency of the perceptron equals 1k samples/s. The structure of the preprocessor makes it possible to implement it using a standard digital CMOS technology. The operation of the preprocessor was discussed using an example of a current signal monitor recognizing specified events. This paper discusses the perceptron sensitivity to the dispersion of the supply voltage and operating temperature.
    Print ISSN: 1530-437X
    Electronic ISSN: 1558-1748
    Topics: Electrical Engineering, Measurement and Control Technology
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  • 94
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-08-12
    Description: Despite decades of research, the study into the application of ultrasonic sensors in process tomography continues to be a subject of significant scientific interest. In this paper, we present a contemporary review of ultrasonic tomography (UT) systems for the application of liquid–gas multiphase flow. The evolution of this topic over the years and an overview of the UT system, measurement strategies, data acquisition, and image reconstruction techniques are described.
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  • 95
    Publication Date: 2017-08-12
    Description: A concentration of acetone in blood and urine can be used as a potential biomarker for clinical diagnosis such as diabetes mellitus type 1. In this paper, a fiber-optic biosensor exploiting consumption of nicotinamide adenine dinucleotide (NADH) was developed for determination of acetone concentration in an aqueous solution. An optical system for the biosensor was constructed with an ultraviolet-light emitting diode excitation system, a photomultiplier tube and an optical fiber probe. The biosensor was fabricated by attaching a membrane, where NADH-dependent secondary alcohol dehydrogenase (S-ADH) was immobilized to the fiber probe. Measurement of the acetone concentration was carried out by immersing the sensor probe in phosphate buffer solution, which contained a coenzyme, NADH. NADH was consumed by the enzymatic reaction with S-ADH, and the consumption was proportional to the acetone concentration. Fluorescence light emitted from NADH was then guided to the photomultiplier tube. Effect of the buffer pH and NADH concentration to the sensor performance, and the selectivity to acetone were also evaluated. As a result, the fluorescence intensity decreased as the acetone concentration increased. A relation between the change of fluorescence intensity and the acetone concentration was found from 0.2 to $50~\mu $ mol/L using decrease phenomena of NADH fluorescence for determination of the acetone concentration. The highly sensitive and selective acetone biosensor is the potential tool for diagnosis of diabetes in near future.
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  • 96
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-08-12
    Description: A novel low-cost technique for refractive index (RI) measurement is proposed and experimentally demonstrated based on the concept of deep frequency modulation (DFM). By omitting electro-optic modulator from conventional DFM, the frequency modulation is realized by direct current modulation of a laser diode which leads to cost reduction. The flicker noise effect on the DFM performance, which is considered as a major obstacle of homodyne detection, has been considered in our numerical analysis; hence, a realistic analysis of the results is presented. Hereby, a modification in the DFM signal processing has been suggested to mitigate the flicker noise effect. Through proper selection of higher harmonics of the wideband detected DFM signal, the normalized error can be reduced more than 10 dB. We have implemented this method for a Michelson interferometer to measure RI of an aqueous solution. An interference signal is formed on the photodetector, which is then processed to measure RI by estimating the optical path length difference between the two interferometer arms. It is shown that this setup provides a resolution of better than $2.1 \times {10^{-5}}$ in RI unit. The proposed cost-effective measurement technique can be readily integrated in applications, where high precision real-time measurements over a wide measurement range are required.
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  • 97
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-08-12
    Description: A voltammetric sensor for the determination of chloride ions is proposed. At trace level, Hg(II) ions (ca. $15 \times 10^{-12}$ mol or only approximately 3 Hg 2+ cations per carbon nanoparticle) are adsorbed at the surface of amine-functionalized carbon nanoparticles in a film supported on a glassy carbon electrode. With this redox-active film, voltammetric chloride determination is possible without loss of mercury/signal in repeatable measurements and over a very wide chloride concentration range. The sensor mechanism is based on the shift of the voltammetric peak potential for the Hg/Hg 2 Cl 2 redox transformation in the presence of chloride anions. Only trace-level mercury is employed, so that problems associated with traditional bulk mercury electrodes are not encountered. Differential pulse voltammograms were recorded over a wide range of chloride concentrations resulting in two regimes (from $5 \times 10^{-5}$ to 1 M and from 1 to 3 M) with linear peak potential shift with a chloride concentration of −63.2 ± 0.09 mV/pCl and −109.1 ± 0.4 mV/pCl, respectively (at 25 °C). The sensor performance is promising in real samples, such as lake water, sea water, and table salt.
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  • 98
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-08-12
    Description: Inductorless wide-band low-noise amplifiers (LNAs) usually suffer from poor noise performance, mainly due to the high noise contribution of the matching device. Noise canceling (NC) is a technique used in wide-band LNAs [1]-[13] to nullify the noise contribution of the matching device at the output. NC techniques are often explained with the help of the block diagram shown in Figure 1(a), where the input signal from a source of internal impedance Rs is simultaneously fed to a matching amplifier and a voltage sensing amplifier.
    Print ISSN: 1527-3342
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  • 99
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-08-12
    Description: This book offers a comprehensive guide to the subject of microwave backhaul. Design information on this subject is sparse, and it is not easy to collect and interpret. This fact was the driving force behind the creation of this book, which focuses on the electronics of backhaul and describes in detail all the subsystems responsible for transforming the information signal that comes from baseband processing into an electromagnetic wave traveling through the air. Electronics for Microwave Backhaul presents an overview of the evolution of the electronics for microwave radios, from their initial development to present implementations and future trends. The authors have stayed abreast of current real-world industry products and present many real-world solutions to the design issues.
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  • 100
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    Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2017-08-12
    Description: Presents information on the First IEEE MTT-S Latin America Microwave Conference.
    Print ISSN: 1527-3342
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    Topics: Electrical Engineering, Measurement and Control Technology
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