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The use and advancement of manufacturing technologies related to additive manufacturing significantly increased in the final decade of the 20th century. Technology progressions have led to the creation of methods for streamlining the printing process, emphasizing cutting down on manufacturing time, including the use of Genetic Algorithms (GA). The effect produced by changing the path pattern is interesting for two reasons: a) dimensional accuracy focused on preserving the component’s dimensions and b) the structural composition and strength that the printing process itself can produce. The objective of this article is to compare the effect of modifying the path (GA) versus the manufacturer algorithm (MA) of the 3d printed in two ways, one of them focused on the accuracy dimension of the geometries and the second from the structural point of view through the comparison by using Computed Tomography. Twenty-three geometrical pieces were employed in a template printed using FFF technology and PLA as the foundation material. The total process time needed to print the component was reduced by 11% due to the findings. Regarding the dimensional analysis, the average deviation produced by the GA path is less than that produced by the manufacturer’s suggestion. Regarding the porosity analysis, the GA shows a more significant void percentage but less void dispersion; ironically, the porosity concentrates based on the suggested materials. These results are crucial for product conceptualization and deposition printing planning.

In this article, we apply dimensional analysis to the optimization of radial magnetic torque couplers. Our goal is to find the design that maximizes the torque potential in a given package size. We consider two types of torque coupler: the permanent-magnet (a.k.a. synchronous) torque coupler, in which both the inner and outer rotors contain permanent magnets; and the variable-reluctance torque coupler, in which the inner rotor contains permanent magnets and the outer rotor contains soft-magnetic teeth. Both types of torque coupler are defined by the same set of independent geometric and material parameters. First, the Buckingham $\Pi $ theorem is used to find the minimal set of dimensionless parameters required for design optimization. Then, using a combination of 2-D and 3-D finite-element analysis, we find and characterize the optimal designs. We explicitly consider torque couplers with eight stable magnetic equilibria (i.e., 45° of rotation between stable equilibria), but the methodology can be repeated for other configurations. [ABSTRACT FROM AUTHOR]

Void fraction is one of the most important parameters in gas-liquid two-phase flow, which plays a crucial role in the pressure gradient calculation and the flow pattern analysis. In this paper, a new coaxial line phase sensor based on the electromagnetic wave propagation is designed and phase shift principle is proposed for the void fraction measurement, and the function relationship between the void fraction and phase difference is derived. By the theoretical analysis and 56 static calibration experiments, the measurement model is proposed in this paper. Air-water two-phase flow experiments have been conducted in a vertical tube at 48 flow conditions in a stainless-steel tubular test section which has an inside diameter of 50.0mm. The dimensionless quantities related to the void fraction, e.g. dynamic viscosity ratio, gas-liquid density ratio, gas-phase Froud number (Frg) and Lockhart-Martinelli parameter (${\mathrm {X}}_{{\mathrm {LM}}}$), are dimensional analyzed. According to the $\Pi $ theorem, a new void fraction correlation which could acceptably handle all the available data of different flow conditions (authors’ and literature) is proposed. Laboratory results indicate that the mean absolute error (MAE) of the correlation is 6.46% within an error band of ±10% and 8.03% (183 literature data points) within an error band of ±15%. The void fraction correlation has good prediction accuracy and a certain extrapolation for different flow regimes and fluid characteristic parameters. [ABSTRACT FROM AUTHOR]

Blind Interference Alignment (BIA) schemes create and exploit channel coherence patterns without the knowledge of channel realizations at transmitters, while beamforming schemes rely primarily on channel knowledge available to the transmitters without regard to channel coherence patterns. In order to explore the compatibility of these disparate ideas and the possibility of synergistic gains, this work studies the Degrees of Freedom (DoF) of the 2-user ${(M_{1}\times N_{1})(M_{2}\times N_{2})}$ Multiple-Input Multiple-Output (MIMO) Interference Channel (IC) where Transmitter 1 is equipped with reconfigurable antennas and has no channel knowledge, while Transmitter 2 has partial channel knowledge but no reconfigurable antennas. Taking a fundamental dimensional analysis perspective, the main question is to identify which antenna configurations allow synergistic DoF gains. The main results of this work are two-fold. The first result identifies antenna configurations where both reconfigurable antennas and partial channel knowledge are individually beneficial, as those where $M_{1}< N_{1}< \min (M_{2},N_{2})$. The second result shows that synergistic gains exist in each of these settings, over the best known solutions that rely on either reconfigurable antennas or partial channel knowledge alone. Coding schemes that jointly exploit partial channel knowledge and reconfigurable antennas emerge as a byproduct of the analysis. [ABSTRACT FROM AUTHOR]

High temperature superconductors have zero resistance under critical temperature and the HTS tapes have low thermal conductivity. The China Fusion Engineering Test Reactor(CFETR) project requires current leads with current carrying capacity up to 100 kA, making high temperature superconducting current leads the ideal choice. The main work of this paper is the theoretical analysis and optimization design of the 100 kA HTS current lead. Current leads are designed to minimize heat leakage to the cryogenic system and to reduce the mass flow of cooling gas. In this paper, some important design parameters are introduced firstly, and then one dimensional thermal analysis is carried out for the heat exchanger and high temperature superconductor parts. The LOFA time and overheating time of the current lead were calculated through simulation, and it was verified that the design meets the requirements of the project. Finally, the factors that have great influence on the performance of current leads are analyzed. In view of the four influencing factors, which are joint resistance, GHe inlet temperature, hPw and RRR, we respectively produced an optimized design. [ABSTRACT FROM AUTHOR]

The decibel is widely used in signal propagation. Yet, as commonly presented, it does not behave like normal units in formulas, calculations, or dimensional analysis, which hampers understanding and practical use. All issues are resolved by defining the decibel as just an elementary function in calculus, called the direct decibel, which reflects actual practice and is the simplest for a first introduction. Since students will certainly meet other variants, it is crucial they understand the wider picture and all definitional choices. Recognizing that units and scales are functions yields a unifying framework that explains the common conventions and eliminates unwanted effects. The standard decibel and the concept of level are explained rigorously and issues with the (in)famous “20 lg” rule are resolved. The use of the direct decibel in calculations is illustrated in examples from engineering in general, for propagation in cables and free space, noise, and satellite link budgets. [ABSTRACT FROM AUTHOR]

An efficient thin dielectric sheet (TDS) model is presented to compute the radome targets made from high contrast sandwich structure material. By applying the dimensional analysis, this communication has first ever identified the intrinsic stratified distribution of the diagonal entries in the TDS model. Two scaling schemes are accordingly proposed to recover the well-conditioning of the system matrix. The proposed method can improve the computational efficiency of the radome targets considerably, benefiting the fast simulation in practical engineering. [ABSTRACT FROM AUTHOR]

The article discusses dynamic requirements for designing ground manipulator platforms that can be utilized to verify the performance of controllers developed for space manipulators. Dimensional analysis is used to formalize the dynamic equivalence conditions and control scaling laws between a given space manipulator and the ground manipulator to be designed, such that the space manipulator and the designed ground manipulator are dynamically equivalent. Given that, unlike its space counterpart, the ground manipulator may not have the complete six degrees of freedom for its base and it must function under the gravity effects, as well as manufacturing imprecisions in building the ground manipulator, the sensitivity of dynamic equivalence conditions to the abovementioned factors is analyzed. Furthermore, an error compensation scheme based on the feedback linearization technique is developed to make the closed-loop ground manipulator have similar joint movements to those of the space manipulator under its controller. As a result, ground-based verification experiments can be performed for the controllers that will operate on the space manipulator. The design of a ground manipulator with the error compensation scheme for a specific space manipulator is illustrated through simulations, and it is shown how the performance of a PID controller for the space manipulator can be verified using the designed ground manipulator. [ABSTRACT FROM AUTHOR]

Traditional tensor decomposition methods, e.g., two dimensional principal component analysis and two dimensional singular value decomposition, that minimize mean square errors, are sensitive to outliers. To overcome this problem, in this paper we propose a new robust tensor decomposition method using generalized correntropy criterion (Corr-Tensor). A Lagrange multiplier method is used to effectively optimize the generalized correntropy objective function in an iterative manner. The Corr-Tensor can effectively improve the robustness of tensor decomposition with the existence of outliers without introducing any extra computational cost. Experimental results demonstrated that the proposed method significantly reduces the reconstruction error on face reconstruction and improves the accuracies on handwritten digit recognition and facial image clustering. [ABSTRACT FROM AUTHOR]

Automated controller synthesis methods for cyber–physical systems (CPSs) often require precise knowledge of the system’s state. Unfortunately, parts of the state may not be directly measurable, which limits the application of these methods. We present a design methodology for the co-design of software controllers and the required sensing capabilities. Our method leverages the knowledge of physical units in the model of a system to find ways of indirectly measuring parts of the system’s state which cannot be measured directly. The method contains a search procedure which uses dimensional analysis to explore the space of physically well-typed expressions and it generates as an intermediate result possible sensor combinations. The integration between the physical and software design for CPS that we present make automated controller synthesis techniques more widely applicable. We have implemented our method and applied it to the design of robotic manipulators. [ABSTRACT FROM AUTHOR]

Popular clustering algorithms based on usual distance functions (e.g., the Euclidean distance) often suffer in high dimension, low sample size (HDLSS) situations, where concentration of pairwise distances and violation of neighborhood structure have adverse effects on their performance. In this article, we use a new data-driven dissimilarity measure, called MADD, which takes care of these problems. MADD uses the distance concentration phenomenon to its advantage, and as a result, clustering algorithms based on MADD usually perform well for high dimensional data. We establish it using theoretical as well as numerical studies. We also address the problem of estimating the number of clusters. This is a challenging problem in cluster analysis, and several algorithms are available for it. We show that many of these existing algorithms have superior performance in high dimensions when they are constructed using MADD. We also construct a new estimator based on a penalized version of the Dunn index and prove its consistency in the HDLSS asymptotic regime. Several simulated and real data sets are analyzed to demonstrate the usefulness of MADD for cluster analysis of high dimensional data. [ABSTRACT FROM AUTHOR]

This paper proposes a new approximation of the theoretical signal to interference plus noise ratio (SINR) loss of the low-rank (LR) adaptive filter built on the eigenvalue decomposition of the sample covariance matrix. This new result is based on an analysis in the large dimensional regime, i.e., when the size and the number of data tend to infinity at the same rate. Compared to previous works, this new derivation allows us to measure the quality of the adaptive filter near the LR contribution. Moreover, we propose a new LR adaptive filter and we also derive its SINR loss approximation in a large dimensional regime. We validate these results on a jamming application and test their robustness in a multiple input multiple output space time adaptive processing application where the data size is large. [ABSTRACT FROM AUTHOR]

Intrinsic dimensional analysis and differential entropy estimation are closely related to the point that they can be jointly estimated as two complementary outputs of a single approach. In this brief letter, it is shown that, given a noisy signal, intrinsic dimension and differential entropy, jointly analyzed through visual approach, can be used to estimate noise variance directly from noisy signal samples. Preliminary results corroborating this idea are presented through experiments with chaotic (Lorenz chaotic model) and almost periodic (human vocalization) signals, including comparisons with results from methods in the concerned literature. [ABSTRACT FROM AUTHOR]

In this paper, a large dimensional performance analysis of kernel least squares support vector machines (LS-SVMs) is provided under the assumption of a two-class Gaussian mixture model for the input data. Building upon recent advances in a random matrix theory, we show, when the dimension of data $p$ and their number $n$ are both large, that the LS-SVM decision function can be well approximated by a normally distributed random variable, the mean and variance of which depend explicitly on a local behavior of the kernel function. This theoretical result is then applied to the MNIST and Fashion-MNIST datasets which, despite their non-Gaussianity, exhibit a convincingly close behavior. Most importantly, our analysis provides a deeper understanding of the mechanism into play in SVM-type methods and in particular of the impact on the choice of the kernel function as well as some of their theoretical limits in separating high-dimensional Gaussian vectors. [ABSTRACT FROM AUTHOR]

Over the last decade, empirical mode decomposition (EMD) has developed into a versatile tool for adaptive, scale-based modal decomposition. EMD has proven to be capable of decomposing multivariate signals with cross-channel mode alignment. However, the algorithms for envelope identification in multivariate EMD come with a computational burden rendering it unsuitable for the large computational demands of multidimensional signal processing. The current work introduces an alternative approach to multivariate EMD, and by combining it with existing fast and adaptive algorithms, paves the way for performing multivariate EMD on multidimensional signals. [ABSTRACT FROM AUTHOR]

Oil-flow distribution in the winding has a direct impact on cooling performance. In addition, static pressure drop over the winding determines oil split among windings connected hydraulically in parallel. In this paper, experimental verifications are provided to support computational fluid dynamics (CFD) simulations for disc-type windings in oil-forced and directed (OD) cooling modes. Oil-flow distribution in and pressure drop over disc-type winding models are measured using a particle image velocimetry system and a differential pressure instrument, respectively. Dimensional analysis is adopted to analyze the relationship between flow distribution, or pressure drop, and the controlling parameters. CFD parametric sweeps of the dimensionless parameters obtained from the dimensional analysis are conducted and the CFD results are then correlated with the dimensionless parameters. The comparisons between measured results and corresponding results obtained from the correlations demonstrate constant consistency, proving the validity of both the method of dimensional analysis and the correlations. Finally, comparisons of experimental results from isothermal and nonisothermal conditions in OD cooling modes are executed, which show that the isothermal conclusions can be extended to nonisothermal cases because the effects of buoyancy force and hot-streak dynamics prove to be negligible. [ABSTRACT FROM PUBLISHER]

The image of secondary arc, which is a common phenomenon in ultrahigh voltage power system, contains a wealthy of information. To determine its geometrical characteristics, the secondary arc image is systematically processed involving gray scale, noise filtering, and image segmentation. To overcome the discontinuous and false edge caused by conventional operators, an improved algorithm is employed; the unrelated edges are fully removed, and the interrupted endpoints are dilated. Based on the results, the component and evolution of secondary arc are discussed; the correlation of the arc luminance and arc current is revealed. Occasionally, the arc roots and arc column have irregular motion behavior. Using the edge-detection technique, the detailed jumping location and velocity of anode arc root are tracked; the life expectancy and stability of coexistence of multicathode arc roots are determined; the morphology of short circuit of arc column is ascertained. Furthermore, the secondary arc dimension is estimated in this paper, including the arc radius and arc length. A number of formulas have been presented to predict the dimension. The obtained results are more accuracy than previous works. [ABSTRACT FROM AUTHOR]

Application of the nonthermal plasma (NTP) technology for NOX removal from diesel engine exhaust has already been experimentally proved to be an efficient method at laboratory level. The NOX removal efficiency depends on various electrical and physical parameters, and very few studies have been carried out to predict it with the variation in those parameters. In this paper, an approach has been made using dimensional analysis to predict the NOX concentration with the NTP treatment, based on its dependence on various operating parameters. A relation has been obtained between NOX concentration and 11 numbers of parameters affecting NOX removal so as to form dimensionless groups. A mathematical model has been established using the experimental data and nonlinear regression technique. Experiments are conducted to validate this model with variations in the parameters voltage, flow rate, temperature, discharge gap width, and initial NOX concentration. The predicted NOX concentration values have been found to be well matched with the experimental results. The rms errors for the test data are found to be 4.64%, and in ppm, it is 9.58. [ABSTRACT FROM AUTHOR]

The hot-spot factor (H) is a crucial component of the thermal diagram in IEC 60076-2 to derive the hot-spot temperature from the test data. In this paper, H is expressed as the sum of two separable components, one relating to convection in the fluid domain and the other relating to conduction in the solid domain. Dimensional analyses on fluid flow and heat transfer show that both components are functions of dimensionless winding geometry, loss distribution, Re and Pr. The relationship between H and Re and Pr for a fixed winding geometry with uniform loss distribution is obtained by conducting computational fluid dynamics (CFD) parametric sweeps and multilayer least-square-based correlation. The correlation obtained is verified by the consistency between H from new CFD simulations and those from the correlation. For nonuniform loss distribution, when the hotspot is at the location of the highest power loss, H is in a linear relationship with Q and this linear relationship is coupled with a nonlinear relationship between H and Re and Pr. [ABSTRACT FROM AUTHOR]

The study aims at investigating the influences of the elastoplastic behaviors of the micrometer-thick Ni3Sn4 intermetallic compound (IMC) observed in the Cu/Ni/Sn3.5Ag solder joints of 3-D chip stacking package on the solder joint reliability under accelerated thermal cycling (ATC). The IMC’s elastoplastic properties are characterized through the developed forward-reverse analysis algorithm, which integrates parametric finite element analysis (FEA) of instrumented indentation, dimensional analysis, and an experimental instrumented indentation test. The algorithm is first applied to characterize the elastoplastic behaviors of an electrodeposited Cu thin film, the results of which are compared with the known data, followed by a test on the thin Ni3Sn4IMC. The predicted elastoplastic properties are input to the ATC FEA model of the package to simulate the solder joint mechanical response, by which the corresponding fatigue life is assessed using a Coffin–Manson model. The simulation is validated against the experimental data. Besides, the prediction is compared with that without the plastic effect. Results show that despite bulk IMCs being normally elastic, brittle, and hard, the thin Ni3Sn4 IMC possesses a highly ductile (plastic) and strain-hardening behavior. Moreover, taking the plastic behavior of the thin Ni3Sn4 IMC into account helps improve the prediction of the solder joint fatigue life of the package. [ABSTRACT FROM PUBLISHER]

In this paper, a method for predicting pressure drop and flow distribution in disc-type transformer windings in an oil-forced and directed cooling mode is proposed. First, dimensional analyses are conducted to identify the independent dimensionless variables that affect pressure drop over and flow distribution in the winding. Next, parametric sweeps are performed with computational fluid dynamics simulations under isothermal flow conditions. Finally, pressure drop and flow distribution results obtained from the simulations are correlated with the previously identified dimensionless variables to derive correlation equations. These equations have been verified over a range of different isothermal and non-isothermal flow cases and applied to identify the criteria for the occurrence of reverse flow resulting from a combination of pass inlet flow rate and winding geometry. In addition, the method provides an insight into the controlling parameters to determine the minimum oil velocity in horizontal cooling ducts. [ABSTRACT FROM AUTHOR]

A normal rational curve of the (k-1) -dimensional projective space over {\mathbb F}_{q} is an arc of size q+1$ , since any k$ points of the curve span the whole space. In this paper, we will prove that if q$ is odd, then a subset of size 3k-6$ of a normal rational curve cannot be extended to an arc of size q+2$ . In fact, we prove something slightly stronger. Suppose that q$ is odd and E$ is a (2k-3)$ -subset of an arc G$ of size 3k-6$ . If G$ projects to a subset of a conic from every (k-3)$ -subset of E of odd characteristic, which can be extended to a Reed–Solomon code of length $q+1$ , cannot be extended to a linear maximum distance separable code of length $q+2$ . [ABSTRACT FROM AUTHOR]

This paper studies the problem of recovering the authentic samples that lie on a union of multiple subspaces from their corrupted observations. Due to the high-dimensional and massive nature of today’s data-driven community, it is arguable that the target matrix (i.e., authentic sample matrix) to recover is often low-rank. In this case, the recently established Robust Principal Component Analysis (RPCA) method already provides us a convenient way to solve the problem of recovering mixture data. However, in general, RPCA is not good enough because the incoherent condition assumed by RPCA is not so consistent with the mixture structure of multiple subspaces. Namely, when the subspace number grows, the row-coherence of data keeps heightening and, accordingly, RPCA degrades. To overcome the challenges arising from mixture data, we suggest to consider LRR in this paper. We elucidate that LRR can well handle mixture data, as long as its dictionary is configured appropriately. More precisely, we mathematically prove that LRR can weaken the dependence on the row-coherence, provided that the dictionary is well-conditioned and has a rank of not too high. In particular, if the dictionary itself is sufficiently low-rank, then the dependence on the row-coherence can be completely removed. These provide some elementary principles for dictionary learning and naturally lead to a practical algorithm for recovering mixture data. Our experiments on randomly generated matrices and real motion sequences show promising results. [ABSTRACT FROM AUTHOR]

A compact linearly polarized dual-band patch antenna with low cross-polarization and independent band control is presented. Miniaturization was achieved through a combination of shorting, subsequently folding, and by replacing the standard slot loading with a slot that is featured by a meander line. By replacing the standard straight slot with an interdigitated slot loading, the resonance condition was shifted to the lower operating band, facilitating significant antenna miniaturization and resulting in an element size equal to or smaller than 0.1\lambda {0} in all three dimensions. The antenna design procedure is outlined and a prototype for WiFi applications was fabricated and measured for impedance matching, radiation pattern, and broadside gain. A simulated parametric analysis was performed on the interdigitated slot geometry to determine how the antenna performance is controlled. Then, based on the parametric analysis, it was further demonstrated that the two operational bands of the antenna element could be independently controlled by changing only the geometrical dimensions of the interdigitated slot, leaving the base of the antenna entirely unaltered. As a result, the lower operating band could be fixed while the upper operating band could be shifted by up to 10%. Lastly, the effect of utilizing a small ground plane, in an effort to achieve a small antenna footprint, is discussed. [ABSTRACT FROM AUTHOR]

In this paper, we consider the use of dimensional analysis for modeling electromagnetic levitation and braking problems, which are described by the Lorentz force law. Based on Maxwell’s equations, to illustrate the underlying field problem, we formulate a complete mathematical model of a simple academic example, where a permanent magnet is moving over an infinite plate at constant velocity. The step-by-step procedure employed for dimensional analysis is described in detail for the given problem. A dimensionless model with a reduced number of parameters is obtained, which highlights the dominant dependences, and it is invariant to the dimensional system employed. Using the dimensionless model, a concise parametric study is conducted to illustrate the advantages of the dimensionless representation for displaying complex data in an efficient manner. We provide an exhaustive study of the dependences of the Lorentz force on the dimensionless parameters to complete the analysis, and we give results for a generalized representation of the problem. Finally, scaling laws are derived and illustrated based on practical examples. [ABSTRACT FROM PUBLISHER]

This article presents the dimensional analysis conceptual modeling (DACM) framework, intended as a conceptual modeling mechanism for lifecycle systems engineering. DACM is a novel computer-aided method originally developed for military projects, but it's now available for other applications, too. The DACM framework is a powerful approach for specifying, discovering, validating, and reusing building blocks as well as analyzing system behavior in early development stages. This framework is based on dimensional analysis combined with causal graphs to represent the interactions and interdependencies among system variables. The framework's algorithms are codified into software applications to facilitate its use. This article provides a practical presentation of the steps that encompass the transformation from problem to solution space, key system variables extraction, causal ordering, clustering of variables, and qualitative analyses. The authors provide two examples that cover in detail the DACM's mathematic machinery for deriving a system's behavioral laws from a causal graph. The entire DACM approach is supported by a computer-based application that integrates all the steps of the framework presented in this article. [ABSTRACT FROM PUBLISHER]

The presentation and visualization of tradeoff solutions in many-objective optimization problems are difficult due to the large number of solutions in a hyperdimensional objective space. A recently proposed tool, known as aggregation tree (AT), can be used to analyze the degree of conflict between groups of objectives in a many-objective problem. In this paper, we present a case study on the internal permanent magnet motor design with seven objectives. The results show that the AT provides useful information about objective relationships (in accordance with the common knowledge of physics) as well as guidance in the reduction of objectives. [ABSTRACT FROM AUTHOR]

A 3-dimensional Built-In Self-Repair (3D BISR) scheme is proposed for 3-dimensional (3D) memories. The proposed 3D BISR scheme consists of two phases: a parallel test-repair phase, and a serial test-repair phase. After all memory dice are simultaneously tested, only the faulty memory dice are serially tested and repaired using one Built-In Redundancy Analysis (BIRA) module. Thus, it is a faster test-repair with low area overhead. The proposed BIRA algorithm with a post-share redundancy scheme performs exhaustive searches for all combinations of spare rows and columns. Experimental results show that the proposed 3D BISR is up to two times faster than the 3D serial test-serial repair BISR when seven 2048 \times 2048 bit memory dice are stacked. The proposed 3D BISR requires 44.55% of the area in comparison to a 3D parallel test-parallel repair BISR for four stacked memory dice (one 128 K RAM, two 256 K RAMs, and 512 K RAM). The yield of 3D memories is the highest due to the exhaustive search BIRA algorithm with the post-share redundancy scheme as shown in various experimental results. [ABSTRACT FROM AUTHOR]

Imaging of electrical trees has been an important tool for studying the phenomenon. The authors have previously shown that electrical trees can be three-dimensionally (3D) imaged and virtual replicas generated using X-ray Computed Tomography (XCT) or Serial Block-Face Scanning Electron Microscopy (SBFSEM). Here these techniques are evaluated and compared for 3D analysis of electrical trees along with conventional optical methods. A number of types of laboratory created trees showing range of morphologies were grown and examined to delineate the capabilities of each technique. Cross-sectional images and virtual replicas of the electrical trees from XCT and SBFSEM techniques were compared both qualitatively and quantitatively. SBFSEM provides greater detail than XCT, evidenced by imaging smaller sub-branches and when comparing parameters such as the number of tree channels, tree length or tree volume captured. On average, SBFSEM captures almost double the number of tree channels per slice than XCT, and virtual replicas in most of the cases have larger volumes. However, SBFSEM is a destructive technique, which makes the imaging process less reliable than XCT and not suitable for multi-stage of tree growth experiments. For full analysis, a combination of imaging techniques is proposed. Optical methods are used first to monitor tree growth. Then, micro-XCT which provides pixel size down to ~0.4 μm with a field of view of around 1 mm x 1 mm, can be used to reveal the overall 3D structure of a normal/mature electrical tree. Nano-XCT can be used to explore in more detail regions of interest, with a pixel size of ~65 nm, but a limited field of view of 65 ?m. Finally, sections of the tree can be analyzed in even greater detail using SBFSEM, which can provide resolutions below 50 nm. Using this approach, a deeper and more complete analysis of the structure of electrical trees can be achieved. [ABSTRACT FROM AUTHOR]

Recently, diagnostic on Medium Voltage Cables using tan δ measurement that measures dissipation factor with 0.1Hz VLF (Very Low Frequency) high voltage source has emerged as an efficient way to assess water tree aging of MV (Medium Voltage) cables. This study verified the validity diagnostic evaluation criteria defined by IEEE400.2-2013 and it?s pervious drafts of DTD (Delta tan δ) and STDEV (Standard Deviation) - indicating voltage-stability and time-stability of tan δ respectively - by applying tan δ measurement to KEPCO (Korea Electric Power Corporation)'s power distribution system and suggested a new assessment factor being defined as Skirt, and its new formula in order to identify the precursor of insulation breakdown with patterns of tan δ. By visualizing complex correlations between various assessment factors and proposing a 3-dimensional assessment standard that can normalize the deterioration condition of a cable into a uniform value, this study has established a foundation to calculate the remaining life time of a cable through VLF tan δ diagnostic. [ABSTRACT FROM AUTHOR]

Three-dimensional movie acquisition and corresponding depth data is commonly generated from multiple cameras and multiple views. This technology has high cost and large size which are limitations for current consumer products, such as small camcorders and cell phone movie cameras. This research result shows that a single imager, equipped with a fast-focus microfluidic lens, produces a highly accurate depth map. On test material, the depth is found to be an average Root Mean Squared Error (RMSE) of 4.67 gray level steps (1.8%) accuracy compared to ranging data. The depth is inferred using a new Extended Depth from Defocus (EDfD), and defocus is achieved at movie speeds with a microfluidic lens. In addition, early indications show that real-time HDTV 3D movie frame rates are feasible. [ABSTRACT FROM PUBLISHER]

High-dimensional data arise naturally in many domains, and have regularly presented a great challenge for traditional data mining techniques, both in terms of effectiveness and efficiency. Clustering becomes difficult due to the increasing sparsity of such data, as well as the increasing difficulty in distinguishing distances between data points. In this paper, we take a novel perspective on the problem of clustering high-dimensional data. Instead of attempting to avoid the curse of dimensionality by observing a lower dimensional feature subspace, we embrace dimensionality by taking advantage of inherently high-dimensional phenomena. More specifically, we show that hubness, i.e., the tendency of high-dimensional data to contain points (hubs) that frequently occur in $(k)$-nearest-neighbor lists of other points, can be successfully exploited in clustering. We validate our hypothesis by demonstrating that hubness is a good measure of point centrality within a high-dimensional data cluster, and by proposing several hubness-based clustering algorithms, showing that major hubs can be used effectively as cluster prototypes or as guides during the search for centroid-based cluster configurations. Experimental results demonstrate good performance of our algorithms in multiple settings, particularly in the presence of large quantities of noise. The proposed methods are tailored mostly for detecting approximately hyperspherical clusters and need to be extended to properly handle clusters of arbitrary shapes. [ABSTRACT FROM PUBLISHER]

An electromagnetic (EM) cell is demonstrated to create the uniform electric field with 3-D polarization dynamic control for the EM compatibility/interference (EMC/EMI) testing. We utilize 3-D orthogonal slotline structures to build the walls of the EM cell and produce uniform electric field inside the cell by feeding the slotlines in phase and terminating them with matching loads. The uniform electric field is similar to a standing wave produced by the slotline modes propagating in opposite directions. Microwave switches are integrated into the slotlines so that we can choose the operating slotline dynamically and change its orientation in a 3-D manner by adjusting the ON/OFF state of the appropriate switches, which will consequently change orthogonally the polarization of the EM field generated by the operating slotline in 3-D. Both simulation and experiment show that a polarization controllable uniform field can be achieved in the center region of the EM cell from dc frequency to its first EM resonant frequency, enabling EMC/EMI testing more flexible without rotating the device under test. [ABSTRACT FROM PUBLISHER]

This paper presents, through an illustrative example, a 3-D modeling approach to predict the electromagnetic interference (EMI) between complex electronic devices and interconnections placed in the near-field region. Three different analytic coupling formulations have been investigated along with a 3-D-emission model to evaluate the induced voltages in transmission line (TL) extremities in the case of both matched and mismatched TL configurations. The proposed modeling method is successfully validated by comparison with numerical results using electromagnetic (EM) simulation tools and experimental results using near-field measurement. The obtained EM coupling results are more accurate than other traditional 2-D models. [ABSTRACT FROM PUBLISHER]

It is a nontrivial task to build an accurate emerging pattern (EP) classifier from high-dimensional data because we inevitably face two challenges 1) how to efficiently extract a minimal set of strongly predictive EPs from an explosive number of candidate patterns, and 2) how to handle the highly sensitive choice of the minimal support threshold. To address these two challenges, we bridge causal relevance and EP discriminability (the predictive ability of emerging patterns) to facilitate EP mining and propose a new framework of mining EPs from high-dimensional data. In this framework, we study the relationships between causal relevance in a causal Bayesian network and EP discriminability in EP mining, and then reduce the pattern space of EP mining to direct causes and direct effects, or the Markov blanket (MB) of the class attribute in a causal Bayesian network. The proposed framework is instantiated by two EPs-based classifiers, CE-EP and MB-EP, where CE stands for direct Causes and direct Effects, and MB for Markov Blanket. Extensive experiments on a broad range of data sets validate the effectiveness of the CE-EP and MB-EP classifiers against other well-established methods, in terms of predictive accuracy, pattern numbers, running time, and sensitivity analysis. [ABSTRACT FROM PUBLISHER]

In dealing with post-sale warranties, considering only operating time may not be sufficient because products often deteriorate through usage and over time, which both influence product reliability. A two-dimensional warranty is thus more reasonable in practice for both manufacturers and customers. Periodic preventive maintenance within the warranty term seems more prevalent in practice due to its convenience and operability for manufacturers and consumers. However, increases in product deterioration may cause breakdowns to occur more often, even after periodic preventive maintenance has just been performed. In this study, a two-dimensional warranty policy is examined with consideration of non-periodic preventive maintenance to determine the optimal two-dimensional warranty term with a constraint that the product reliability should be above a certain threshold. A numerical application is provided to demonstrate the effectiveness of the proposed approach, with sensitivity analyses being conducted to investigate the robustness of the derived optimal warranty policy. [ABSTRACT FROM AUTHOR]

When designing transient suppression circuits housed on interface assemblies to protect internal circuits from power surges, there exists a need to accurately determine the minimum printed circuit board (PCB) trace width required to tolerate given transients without fusing due to overheating. This paper presents four different PCB trace models that may be used for this purpose. The predicted trace widths are compared with each other for validation by comparison. In addition, selected results are tested to further validate the accuracy of the models. [ABSTRACT FROM PUBLISHER]

The work presented here is concerned with performance analysis for data association, in a target tracking environment. Effects of misassociation are considered in a simple (linear) multiscan framework so as to provide closed-form expressions of the probability of correct association. We focus here on the development of explicit approximations of this probability. Via rigorous calculations the effect of dimensioning parameters (number of scans, false measurement positions or densities) is analyzed, for various modelings of the false measurements. Remarkably, it is possible to derive very simple expressions of the probability of correct association which are independent of the scenario kinematic parameters. [ABSTRACT FROM AUTHOR]

In this paper, a nonorthogonal locally 1-D finite difference time-domain (LOD-NFDTD) method is presented for electromagnetic (EM) scattering involving curvilinear coordinate system. Formulations of scattered field and convolutional perfectly matched layer absorbing boundary condition in generalized nonorthogonal grids for LOD-NFDTD are also presented. The nonorthogonal grids are used to fully mesh the computational domain which leads to efficient computation. Moreover, the proposed technique requires fewer arithmetic operations than the alternating direction implicit NFDTD method leading to a reduction of CPU time. The numerical dispersion of the proposed method as a function of Courant-friedrich-lewy number (CFLN) is also presented. Computational results for EM scattering from 2-D conducting, dielectric, and coated cylinders as well as overfilled dielectric and bent cavity structures are presented. [ABSTRACT FROM PUBLISHER]

We analyze the conduction bands of the one dimensional noble-metal chains that contain a Co magnetic impurity by means of ab initio calculations. We compare the results obtained for Cu and Ag pure chains, as well as O doped Cu, Ag and Au chains with those previously found for Au pure chains. We find similar results in the case of Cu and Au hosts, whereas for Ag chains a different behavior is obtained. Differences and similarities among the different systems are analyzed by comparing the electronic structure of the three noble-metal hosts. The d orbitals of Cu chains at the Fermi level have the same symmetry as in the case of Au chains. These orbitals hybridize with the corresponding ones of the Co impurity, giving rise to the possibility of exhibiting a two-channel Kondo physics. [ABSTRACT FROM PUBLISHER]

Laser and heavy-ion data reveal the areas and shapes of single-event latchup (SEL)-sensitive regions in CMOS test structures and their positions relative to the affected \p-n-p-n paths. Contrary to previous two-dimensional studies, this three-dimensional study shows that the position of maximum SEL sensitivity in these structures is not centered on a \p-n-p-n region, but between two neighboring \p-n-p-n regions, suggesting that synergistic triggering increases SEL sensitivity. [ABSTRACT FROM AUTHOR]

This paper presents a procedure for synthesizing high-quality grasps for objects that need to be held and manipulated in a specific way, characterized by a prespecified set of contact constraints to be satisfied. Due to the multimodal nature of typical grasp quality measures, approaches that resort to local optimization methods are likely to get trapped into local extrema on such a problem. An additional difficulty is that the set of feasible grasps is a highly dimensional manifold, implicitly defined by a system of nonlinear equations. The proposed procedure finds a way around these issues by focusing the exploration on a relevant subset of grasps of lower dimension and tracing this subset exhaustively using a higher-dimensional continuation technique. A detailed atlas of the subset is obtained as a result, on which the highest quality grasp, according to any desired criterion, or a combination of criteria, can be readily identified. Examples are included that illustrate the application of the method to a three-fingered planar hand and to the Schunk anthropomorphic hand grasping different objects, using several quality indices. [ABSTRACT FROM AUTHOR]

A concept of simultaneous electric (E) and magnetic (H) 2-D tuning is presented, demonstrated, and applied for the first time through the theoretical and experimental studies of parameter-agile substrated integrated waveguide (SIW) devices. First of all, a two-dimensionally tuned SIW cavity is introduced as a building block. Considering only electric tuning with varactor diodes, no more than 1.3% of total tuning range is accomplished, while for simultaneous electric and magnetic tuning, it is extended to 7.9% with an unloaded Q factor of better than 130. Using 0.05–0.1-pF surface mount capacitors, a total tuning range of as much as 20% is experimentally achieved at 12 GHz. Another characteristic of significant interest is that the proposed 2-D tuning not only allows changing frequency, but also simultaneously optimizing other key parameters such as the return loss or unloaded Q factor. Second, the dual-tuned SIW cavity resonator is further accommodated to demonstrate parameter agile two-dimensionally tuned bandpass filter at 12 GHz. The proposed concept of 2-D tuning theoretically and experimentally demonstrates a simultaneous frequency and bandwidth tuning of bandpass filter. This filter can perform both frequency-tunable constant bandwidth, and constant-frequency variable-bandwidth operations. Third, a cavity backed slot antenna using the proposed dual tuning is demonstrated. The tuning not only achieves a higher frequency range, but the antenna return loss is optimized to improve the overall efficiency. [ABSTRACT FROM PUBLISHER]

Prior velocity and acceleration distributions are often applied in one point initialization, where the track state is initialized based on a single measurement. This distribution is often approximated by a (first two moments preserving) Gaussian distribution. These parameters are derived as a function of the problem dimensionality and target trajectory assumptions. [ABSTRACT FROM PUBLISHER]

This paper presents a real-time control framework for a snake robot with hyper-kinematic redundancy under dynamic active constraints for minimally invasive surgery. A proximity query (PQ) formulation is proposed to compute the deviation of the robot motion from predefined anatomical constraints. The proposed method is generic and can be applied to any snake robot represented as a set of control vertices. The proposed PQ formulation is implemented on a graphic processing unit, allowing for fast updates over 1 kHz. We also demonstrate that the robot joint space can be characterized into lower dimensional space for smooth articulation. A novel motion parameterization scheme in polar coordinates is proposed to describe the transition of motion, thus allowing for direct manual control of the robot using standard interface devices with limited degrees of freedom. Under the proposed framework, the correct alignment between the visual and motor axes is ensured, and haptic guidance is provided to prevent excessive force applied to the tissue by the robot body. A resistance force is further incorporated to enhance smooth pursuit movement matched to the dynamic response and actuation limit of the robot. To demonstrate the practical value of the proposed platform with enhanced ergonomic control, detailed quantitative performance evaluation was conducted on a group of subjects performing simulated intraluminal and intracavity endoscopic tasks. [ABSTRACT FROM AUTHOR]