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Three-dimensional (3-D) meshes are commonly used to represent virtual surfaces and volumes. Over the past decade, 3-D meshes have emerged in industrial, medical, and entertainment applications, being of large practical significance for 3-D mesh steganography and steganalysis. In this article, we provide a systematic survey of the literature on 3-D mesh steganography and steganalysis. Compared with an earlier survey (Girdhar et al., 2017), we propose a new taxonomy of steganographic algorithms with four categories: 1) two-state domain, 2) LSB domain, 3) permutation domain, and 4) transform domain. Regarding steganalysis algorithms, we divide them into two categories: 1) universal steganalysis and 2) specific steganalysis. For each category, the history of technical developments and the current technological level are introduced and discussed. Finally, we highlight some promising future research directions and challenges in improving the performance of 3-D mesh steganography and steganalysis. [ABSTRACT FROM AUTHOR]

Particulate matter has important influences on premature human mortality. Diesel particulate filter is one of the most effective means to reduce particulate matter in exhaust gas. In order to study the 3-D flow characteristics of diesel particulate filter porous structure, lattice Boltzmann method is used to study the flow and heat transfer characteristics of different structures. In some software, the spherical structure is used as diesel particulate filter porous structure. In paper, the spherical structure, the quartet structure generation set structure, and the computer tomography technique structure are constructed. The computer tomography technique structure is constructed by the serial sections of diesel particulate filter porous structure. The flow and heat transfer characteristics in different structures were simulated by lattice Boltzmann method. The 3-D computer tomography technique structure is constructed by superposing the serial section data of diesel particulate filter. The results show that the pressure gradient and temperature gradient of structures are greatly affected by the structure. The pressure gradient and temperature gradient of the spherical structure is the lowest. The spherical structure and the quartet structure generation set structure are different from the porous structure of diesel particulate filter in pressure gradient and temperature gradient. By comparing different structures, it can be seen that although the pressure gradients of the computer tomography technique structure and the quartet structure generation set structure are similar, the temperature gradient of the two structures are more different. [ABSTRACT FROM AUTHOR]

Image skeletonisation plays an important role in applications such as object identification, object's shape description, pattern recognition, computer vision, telemedicine, and image compression. In this paper, an architecture is developed for the extraction of a skeleton for the 3-D greyscale object. The algorithm used in this paper is an extension of the 2-D greyscale skeletonisation algorithm presented in the literature. The skeleton of a 3-D greyscale object is extracted by using the boundary peeling off method. The skeletonisation algorithms are computationally intensive and difficult to achieve requirements in real-time. Field Programmable Gate Arrays (FPGAs) are selected for implementation so the real-time requirements are met. The proposed architecture is implemented on Virtex-5 FPGA and tested for an 8 × 8 x 3 greyscale object. Resource utilisation of FPGA and timing performance are investigated and are encouraging. [ABSTRACT FROM AUTHOR]

The terms "3D" and "3-D" are two alternative acronyms for the term "three-dimensional" In the published literature both variants are commonly used but what is the derivation of the two forms and what are the drivers of usage? This paper surveys the published stereoscopic literature and examines publication-style policies to understand forces and trends. [ABSTRACT FROM AUTHOR]

We describe a novel 3-D ultrasound technology, the quantitative transmission ultrasound system and algorithm to image a pendent breast in a water bath. Quantitative accuracy is verified using phantoms. Morphological accuracy is verified using cadaveric breast and in vivo images, and spatial resolution is estimated. This paper generalizes an earlier 2-D algorithm to a full 3-D inversion algorithm and shows the importance of such a 3-D algorithm for artifact suppression as compared with the 2-D algorithm. The resultant high-resolution ultrasound images, along with quantitative information regarding tissue speed of sound/stiffness, provide a more accurate depiction of the breast anatomy and lesions, contributing to improved breast care. [ABSTRACT FROM PUBLISHER]

In this paper, the requirements of device cross section and aspect ratio (AR) are examined to facilitate steep switching in heavily doped 3-D multiple gate junctionless (JL) transistors. It is shown through well-calibrated simulations and physical insights that the sharp OFF-to- ON switching action is predominantly governed by the area of cross section (${A} _{\textsf {cross}}$) instead of the gate length. A 3-D JL architecture preferably oriented toward a planar topology, i.e., with wider fin and low AR, is conducive for steep switching as a greater bulk area is available for impact ionization. On the contrary, narrow vertical architectures with AR > 1 suppress ${A} _{\textsf {cross}}$ in the bulk and are less likely to support the steep current transition. Steep switching specific scaling methodology is showcased to attain a sharp increase in drain current with a sub-60 mV/decade swing in a tri-gate JL transistor along with an associated negative value of total gate capacitance. [ABSTRACT FROM AUTHOR]

A magnetohydrodynamic (MHD) thruster is a type of electric motor which does not have mechanical moving parts and directly converts electrical energy into mechanical energy. In this paper, a multiphysics numerical simulation has been performed to investigate the phenomena occurred in the channel of marine MHD thrusters. In this simulation, all electric, magnetic, and fluid flow fields have been considered 3-D. For this purpose, a marine MHD thruster model with saddle-shaped coils is selected, and its dimensions are determined. Then, this thruster is simulated numerically, and its electromagnetic and fluid flow parameters are studied. In this simulation, the effects of seawater electrolysis and end loss are taken into account. An experimental setup is established to validate the results obtained from the numerical simulation. The results reveal that the nonuniformities of the electric and magnetic fields along the channel have a great impact on the performance of the thruster. Unlike the results obtained in the previous studies, it is shown that the velocity near the electrodes is higher than that near the sidewalls arisen from the higher electromagnetic force close to the electrodes. [ABSTRACT FROM AUTHOR]

After an introduction to 3-D technology, and through silicon via (TSV)- and stacking options, this paper provides an overview of failures that can be expected in 3-D technology and lists the potential failure analysis (FA) techniques that can be applied to find these failures and the related challenges. Various failure mechanisms and effects that can be expected in TSVs, such as Cu pumping, voids, liner/barrier breakdown, electromigration, mechanical stress impact, Cu diffusion, plasma-induced damage, and the keep-out-zone, are discussed. Also, failures due to backside processing (thinning-induced damage, charging, and Cu exposure) and stacking (misalignment, voids, solder squeeze-out, electrostatic discharge, stress-induced cracking, and delamination) are listed. The importance of mechanical stress and chip–package interaction as a main threat for failures in 3-D technology is highlighted. The FA techniques are not discussed in detail (references are provided). There is a clear need for techniques that can detect failures, such as small (micrometer and submicrometer range) cracks, voids, and delaminated regions (both planar and vertical). [ABSTRACT FROM PUBLISHER]

Benchmark solutions for the validation of magnetohydrodynamic (MHD) codes are of great importance in the development of MHD solver. Hunt’s case II is recommended as a benchmark case to validate MHD codes related to fusion applications. Hunt’s analytical solution is based on 2-D fully developed laminar flow assumption, which means that the velocity vector has only the flow direction component. In this paper, Hunt’s case II has been numerical simulated to investigate the transverse velocity effect using a 3-D MHD solver developed in OpenFOAM environment. A wide range of Hartmann numbers, Reynolds numbers, and wall conductance ratios is tested. Our results show that the 2-D assumption becomes invalid when the transverse velocity is over the order of 10−3. Therefore, the analytical solution is not suitable for the validation of MHD duct flow at high Reynolds numbers. [ABSTRACT FROM AUTHOR]

This paper investigates the total ionizing dose (TID) sensitivity of nanowire (NW) field-effect transistors (NWFETs). Both X-ray irradiations and self-consistent calculations of charge trapping in dielectrics are performed to study their TID response. First of all, the impact of the NW geometry is investigated. The NWFET TID behavior exhibits a strong dependence as a function of the NWs width while shortening the gate length does not significantly change the TID characteristics of optimized narrow NWFETs. Furthermore, the effect of the bias configuration used during irradiation is discussed to state if nMOS NWFETs could withstand significant amount of TID in several operation conditions. [ABSTRACT FROM PUBLISHER]

Poly-Si (p-Si) channel used in 3-D Flash memory devices is the main source of degraded performance, such as the high interface state density. Charge pumping (CP) signals in the 3-D nanoscale vertical device with p-Si channel are analyzed in this paper using the variable amplitude CP technique. For the first time, it has been demonstrated experimentally that the broad CP edge is due to the threshold voltage variation in the p-Si channel caused by both the trapping in interface states and the source/drain p-n junction diffusion, and their impacts can be separately evaluated. Hot carrier stress in the tunneling FET operation modes and statistical analysis are used to provide supporting evidence. [ABSTRACT FROM PUBLISHER]

An improved 3-D analytical model for axial-flux permanent-magnet eddy-current couplings is presented in this paper. As the problem is solved in a 3-D cylindrical coordinate system, the proposed model directly takes into account the radial edge effects and the curvature effects on the torque prediction without the need of any correction factor. It is shown that, the new analytical model is very accurate, even for the geometries where the curvature effects are very pronounced. Another advantage of the proposed model is the great reduction of computation time compared to 3-D finite-elements simulations and an easier adaptation for parametric studies and optimization. [ABSTRACT FROM PUBLISHER]

With the rapid development of mobile Internet and urban constructions, high-volume and dynamic indoor communications bring challenges to cellular systems. High penetration loss and deep shadowing channels of indoor users may substantially degrade the transmission efficiency and system throughput. To address this issue, this paper proposes a solution using Floating Relay (FR) given the mature technologies of unmanned aerial vehicle (UAV). We target the undesirable channel conditions of indoor users, introduce the FR into the cellular system to improve transmission efficiency and maximize system throughput. Considering the capacity limit of the FR's back-haul link and the maximum transmission power of each user, an optimization problem is formulated to maximize the system throughput. The optimal power allocation strategy is then obtained for each user, and two effective online 3-D placement algorithms are proposed for the FR to approach the optimal location in the unpredictable and predictable scenarios, respectively. Extensive simulations are conducted. The achieved maximum system throughput, convergence rate, and accumulated throughput are used to evaluate the proposed algorithms. According to the comparisons between the two proposed algorithms and with off-line schemes, they show superiorities in their targeted scenarios, respectively. [ABSTRACT FROM AUTHOR]

A 3-D multiple-stacked IC has been proposed to support energy efficiency for data center operations as dynamic RAM (DRAM) scaling improves annually. 3-D multiple-stacked IC is a single package containing multiple dies, stacked together, using through-silicon via (TSV) technology. Despite the advantages of 3-D design, fault occurrence rate increases with feature-size reduction of logic devices, which gets worse for 3-D stacked designs. TSV coupling is one of the main reliability issues for 3-D multiple-stacked IC data TSVs. It has large disruptive effects on signal integrity and transmission delay. In this paper, we first characterize the inductance parasitics in contemporary TSVs, and then we analyze and present a classification for inductive coupling cases. Next, we devise a coding algorithm to mitigate the TSV-to-TSV inductive coupling. The coding method controls the current flow direction in TSVs by adjusting the data bit streams at run time to minimize the inductive coupling effects. After performing formal analyses on the efficiency scalability of devised algorithm, an enhanced approach supporting larger bus sizes is proposed. Our experimental results show that the proposed coding algorithm yields significant improvements, while its hardware-implemented encoder results in tangible latency, power consumption, and area. [ABSTRACT FROM AUTHOR]

Multiple-input multiple-output (MIMO) radars have been shown to improve target detection for surveillance applications thanks to their proven high-performance properties. In this paper, the design, implementation, and results of a complete 3-D imaging frequency-modulated continuous-wave MIMO radar demonstrator are presented. The radar sensor working frequency range spans between 16 and 17 GHz, and the proposed solution is based on a 24-transmitter and 24-receiver MIMO radar architecture, implemented by time-division multiplexing of the transmit signals. A modular approach based on conventional low-cost printed circuit boards is used for the transmit and receive systems. Using digital beamforming algorithms and radar processing techniques on the received signals, a high-resolution 3-D sensing of the range, azimuth, and elevation can be calculated. With the current antenna configuration, an angular resolution of 2.9° can be reached. Furthermore, by taking advantage of the 1-GHz bandwidth of the system, a range resolution of 0.5 m is achieved. The radio-frequency front-end, digital system and radar signal processing units are here presented. The medium-range surveillance potential and the high-resolution capabilities of the MIMO radar are proved with results in the form of radar images captured from the field measurements. [ABSTRACT FROM AUTHOR]

This paper presents an efficient 3-D finite-difference time-domain (FDTD) subgridding scheme that is free of the Courant-Friedrichs-Lewy stability condition, for the modeling of ground-penetrating radar (GPR) scenarios in lossy dispersive media. Spatial filtering of FDTD fields within the subgrid is employed to render the time step independent of the cell size in the fine-cell subgrids. This process is applied with minimal modification of the original FDTD code, no implicit operations, and very modest computational overhead. Moreover, multiterm dispersion is included to model practical GPR scenarios involving the detection of realistic scatterers within dispersive soil. Several numerical examples are provided to demonstrate the potential of the proposed method as a powerful GPR modeling tool. [ABSTRACT FROM PUBLISHER]

A novel reconfigurable 3-D frequency selective surface (FSS) exhibiting bandstop response is proposed in this paper. The unit cell of the proposed 3-D FSS is constructed from concentric threaded cylinders. The proposed novel 3-D FSS achieves reconfigurability by sliding technique. It offers frequency tuning from 1.86 to 3.10 GHz by sliding the outer cylinder over the inner cylinder. The proposed FSS offers bandstop response in the L- and S-band microwave frequencies. In addition, the proposed 3-D FSS provides polarization- and angular-independent operation. The prototype of the 3-D FSS is fabricated, and the simulation results are validated using measurements. [ABSTRACT FROM PUBLISHER]

Keep-out-zone (KOZ) is a conservative way to prevent any devices/cells from being impacted by the through-silicon-via (TSV)-induced stress. In this paper, an effective approach was proposed of reducing the KOZ induced by coaxial TSV, by using the structure of coaxial-annular TSV, without decreasing the electrical performance of coaxial TSV. The analytical model was developed appropriate for the thermal stress induced by both coaxial and coaxial-annular TSVs, and was verified by the finite element method. The KOZs induced by coaxial and coaxial-annular TSVs were compared in detail, and the effects of Cu plasticity, TSV material, TSV size, and inner metal plating ratio of coaxial-annular TSV were also studied. The electrical characteristics of different TSVs were compared by employing ANSYS’ HFSS, and a feasible fabrication process for coaxial-annular TSV was suggested. It could be concluded that: 1) a 1.6- \(\mu \) m (22.2%) drop of KOZ for coaxial-annular TSV could be reached as compared with that of coaxial TSV; 2) coaxial-annular TSV was proved to offer the same superior signal integrity with coaxial TSV, improving S21 by about 93% at 5 GHz and 60% at 20 GHz compared with ordinary cylindrical and annular TSVs; and 3) the coaxial-annular TSV is realizable. [ABSTRACT FROM AUTHOR]

This paper presents a prototype human motion tracking system for wearable sports applications. It can be particularly applicable for tracking human motion during executing certain strength training exercises, such as the barbell squat, where an inappropriate technique could result in an injury. The key novelty of the proposed system is twofold. Firstly, it is an inside-out, multimodal, motion tracker that incorporates two complementary sensor modalities, i.e. a camera and an inertial motion sensor, as well as two externally-mounted points of reference. Secondly, it incorporates a novel multimodal sensor fusion algorithm which uses the complementary nature of vision and inertial sensor modalities to perform a computationally efficient 3-Dimensional (3-D) pose detection of the wearable device. The 3-D pose is determined by fusing information about the two external reference points captured by the camera together with the orientation angles captured by the inertial motion sensor. The accuracy of the prototype was experimentally validated in laboratory conditions. The main findings are as follows. The Root Mean Square Error (RMSE) in 3-D position calculation was 36.7 mm and 13.6 mm in the static and mobile cases, respectively. Whereas the static case was aimed at determining the system’s performance at all 3-D poses within the work envelope, the mobile case was used to determine the error in tracking human motion that is involved in the barbell squat, i.e. a mainly repeated vertical motion pattern. [ABSTRACT FROM AUTHOR]

This paper investigates the three-dimensional (3-D) path following control problem for an under-actuated robotic dolphin. With a comprehensive consideration of the mechanical constraint and swimming principle of the robotic dolphin, a decoupling motion strategy is proposed to produce yaw and pitch maneuvers simultaneously. Then, kinematics and dynamics models for 3-D dolphin-like swimming are established, followed by simulations of the path following control. Furthermore, a novel lookahead based 3-D line-of-sight (LOS) guidance law is developed and implemented to obtain desired attitude angles with its simplicity, intuitiveness, and small computational footprint. Finally, simulation results illustrate the feasibility and effectiveness of the proposed path following control methods. [ABSTRACT FROM AUTHOR]

A dual-band dual-circularly polarized (CP) all-metal antenna is proposed in this paper for vehicular communications to realize large signal coverage and high isolation over two bands. On the one hand, by combining two rings of three-dimensional (3-D) L-shaped stubs and a circular patch, opposite CP radiations, i.e., right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP), can be achieved in lower and higher working frequency bands respectively, thus ensuring the isolation between different channels. On the other hand, both radiation patterns of two bands are conical-beam, i.e., omnidirectional, so as to realize large signal coverage, which is beneficial for vehicular communication especially when the car is moving or located on nonplanar plane. Besides, the proposed antenna is all-metal and can be easily manufactured by computer numerical control (CNC) machining technology. As such, it is expected to have higher power capacity than the conventional printed circuit board (PCB) structure. A prototype operating at 2.6 and 2.98 GHz is fabricated and measured, indicating that small frequency ratio between two operating bands can be realized. The proposed antenna is promisingly useful for application on vehicle to ensure simultaneous communications between different links without crosstalk, such as vehicle-to-satellite and vehicle-to-basestation communications. [ABSTRACT FROM AUTHOR]

Computer-generated models of the human body generally do not adequately model the complex human morphology. These models, therefore, do not reflect the anthropometric realities and are not specific enough for commercial use. This paper presents an approach to adjust virtual models through the use of body measurements, as obtained from an anthropometric data set. In this approach, the measurements are used in grouping 3-D body scans, which are obtained using precise optoelectronic measurement devices, into clusters. The virtual mannequins are then adjusted by using the measurements of the nearest cluster member. In this way, realistic accurate virtual mannequins are created. [ABSTRACT FROM AUTHOR]

Extensive growth in functional brain imaging, perfusion-weighted imaging, diffusion-weighted imaging, brain mapping and brain scanning techniques has led tremendously to the importance of the cerebral cortical segmentation, both in 2-D and 3-D, from volumetric brain magnetic resonance imaging data sets. Besides that, recent growth in deformable brain segmentation techniques in 2-D and 3-D has brought the engineering community, such as the areas of computer vision, image processing, pattern recognition and graphics, closer to the medical community, such as to neuro-surgeons, psychiatrists, oncologists, neuro-radiologists and internists. This paper is an attempt to review the state-of-the-art 2-D and 3-D cerebral cortical segmentation techniques from brain magnetic resonance imaging based on three main classes: region-based, boundary/surface-based and fusion of boundary/surface-based with region-based techniques. In the first class, region-based techniques, we demonstrated more than 18 different techniques for segmenting the cerebral cortex from brain slices acquired in orthogonal directions. In the second class, boundary/surface-based, we showed more than ten different techniques to segment the cerebral cortex from magnetic resonance brain volumes. Particular emphasis will be placed by presenting four state-of-the-art systems in the third class, based on the fusion of boundary/surface-based with region-based techniques outlined in Part II of the paper, also called regional-geometric deformation models, which take the paradigm of partial differential equations in the level set framework. We also discuss the pros and cons of various techniques, besides giving the mathematical foundations for each sub-class in the cortical taxonomy. [ABSTRACT FROM AUTHOR]

We have developed a two-way multi-view 2-D/3-D display combining a liquid crystal lens and horizontally and vertically x times-density pixels (HVxDP) arrangement. The two-way multi-view display features the same display resolution in 2-D and 3-D modes and a quite small color moiré for landscape and portrait, respectively, when using the HVxDP arrangement. In this paper, we realized suitable 3-D properties for achieving a good balance between 3-D moiré and 3-D crosstalk for landscape and portrait by a two-way liquid crystal lens with two kinds of focal lengths for the edge part and the center part of the lens. [ABSTRACT FROM AUTHOR]

Myocarditis is a significant public health concern because of its potential to cause heart failure and sudden death. The standard invasive diagnostic method, endomyocardial biopsy, is typically reserved for cases with severe complications, limiting its widespread use. Conversely, non‐invasive cardiac magnetic resonance (CMR) imaging presents a promising alternative for detecting and monitoring myocarditis, because of its high signal contrast that reveals myocardial involvement. To assist medical professionals via artificial intelligence, the authors introduce generative adversarial networks ‐ multi discriminator (GAN‐MD), a deep learning model that uses binary classification to diagnose myocarditis from CMR images. Their approach employs a series of convolutional neural networks (CNNs) that extract and combine feature vectors for accurate diagnosis. The authors suggest a novel technique for improving the classification precision of CNNs. Using generative adversarial networks (GANs) to create synthetic images for data augmentation, the authors address challenges such as mode collapse and unstable training. Incorporating a reconstruction loss into the GAN loss function requires the generator to produce images reflecting the discriminator features, thus enhancing the generated images' quality to more accurately replicate authentic data patterns. Moreover, combining this loss function with other regularisation methods, such as gradient penalty, has proven to further improve the performance of diverse GAN models. A significant challenge in myocarditis diagnosis is the imbalance of classification, where one class dominates over the other. To mitigate this, the authors introduce a focal loss‐based training method that effectively trains the model on the minority class samples. The GAN‐MD approach, evaluated on the Z‐Alizadeh Sani myocarditis dataset, achieves superior results (F‐measure 86.2%; geometric mean 91.0%) compared with other deep learning models and traditional machine learning methods. [ABSTRACT FROM AUTHOR]

Cancer is one of the leading causes of death in the world, with radiotherapy as one of the treatment options. Radiotherapy planning starts with delineating the affected area from healthy organs, called organs at risk (OAR). A new approach to automatic OAR segmentation in the chest cavity in Computed Tomography (CT) images is presented. The proposed approach is based on the modified U‐Net architecture with the ResNet‐34 encoder, which is the baseline adopted in this work. The new two‐branch CS‐SA U‐Net architecture is proposed, which consists of two parallel U‐Net models in which self‐attention blocks with cosine similarity as query‐key similarity function (CS‐SA) blocks are inserted between the encoder and decoder, which enabled the use of consistency regularisation. The proposed solution demonstrates state‐of‐the‐art performance for the problem of OAR segmentation in CT images on the publicly available SegTHOR benchmark dataset in terms of a Dice coefficient (oesophagus—0.8714, heart—0.9516, trachea—0.9286, aorta—0.9510) and Hausdorff distance (oesophagus—0.2541, heart—0.1514, trachea—0.1722, aorta—0.1114) and significantly outperforms the baseline. The current approach is demonstrated to be viable for improving the quality of OAR segmentation for radiotherapy planning. [ABSTRACT FROM AUTHOR]

Position and orientation of indoor mobile robots must be obtained real timely during operation in structured industrial environment, so as to ensure the security and efficiency of cargo transportation and assembly precision. But for such a large-scale space, only 2-D coordinates and heading angle of the mobile robot can be measured with a relatively low precision in current major methods. This paper presents a novel method for 3-D position and orientation measurement of indoor mobile robot. In this method, a rotary-laser transmitter is utilized, which is mounted on the indoor mobile robot measuring the scanning angles relative to photoelectric artificial landmarks and obtaining its own 3-D space location information. The landmarks whose coordinates in navigation frame should be precalibrated are distributed at the most appropriate positions of the structured industrial environment. On the basis of that, an algorithm of multiangle intersection was established and in-depth discussed to solve transmitter’s spatial position and orientation. Experimental results show that, in an 8~ m\times 6~m\times 2.5 m working volume, transmitter’s position, and orientation measurement accuracy of proposed method were higher than 3.8 mm and 0.104°, respectively. It demonstrates that the proposed method is reliable and flexible for indoor mobile robot navigation tasks and the measurement accuracy can be further improved by increasing layout density of landmarks. [ABSTRACT FROM PUBLISHER]

Synthetic aperture radar (SAR) tomography has been strongly developed in the last years for the analysis at fine scale of data acquired by high-resolution interferometric SAR sensors as a technique alternative to classical persistent scatterer interferometry and able to resolve also multiple scatterers. SqueeSAR is a recently proposed solution which, in the context of SAR interferometry at the coarse scale analysis stage, allows taking advantage of the multilook operation to filter interferometic stacks by extracting, pixel by pixel, equivalent scattering mechanisms from the set of all available interferometric measurement collected in the data covariance matrix. In this paper, we investigate the possibilities to extend SqueeSAR by allowing the identification of multiple scattering mechanisms from the analysis of the covariance matrix. In particular, we present a new approach, named “Component extrAction and sElection SAR” algorithm, that allows taking advantage of the principal component analysis to filter interferograms relevant to the decorrelating scatterer, i.e., scatterers that may exhibit coherence losses depending on the spatial and temporal baseline distributions, and to detect and separate scattering mechanisms possibly interfering in the same pixel due to layover directly at the interferogram generation stage. The proposed module allows providing options useful for classical interferometric processing to monitor ground deformations at lower resolution (coarse scale), as well as for possibly aiding the data calibration preliminary for the subsequent full-resolution interferometric/tomographic (fine scale) analysis. Results achieved by processing high-resolution Cosmo-SkyMed data, characterized by the favorable features of a large baseline span, are presented to explain the advantages and validate this new interferometric processing solution. [ABSTRACT FROM PUBLISHER]

Skilled welders can estimate and control the weld joint penetration, which is primarily measured by the backside bead width, based on weld pool observation. This suggests that an advanced control system could be developed to control the weld joint penetration by emulating the estimation and decisionmaking process of the human welder. In this paper an innovative 3-D vision sensing system is used to measure the characteristic parameters of the weld pool in real-time in gas tungsten arc welding. The measured characteristic parameters are used to estimate the backside bead width, using an adaptive neuro-fuzzy inference system (ANFIS) as an emulation of skilled welder. Dynamic experiments are conducted to establish the model that relates the backside bead width to the welding current and speed. The dynamic linear model is first constructed and the modeling result is analyzed. The linear model is then improved by incorporating a nonlinear operating point modeled by an ANFIS. Because the weld pool needs to gradually change, being controlled by a skilled welder, a model predictive control is used to follow a trajectory to reach the desired backside bead width and the control increment is penalized. Because the weld pool is not supposed to change in an extremely large range, the resultant model predictive control is actually linear and an analytical solution is derived. Welding experiments confirm that the developed control system is effective in achieving the desired weld joint penetration under various disturbances and initial conditions. [ABSTRACT FROM AUTHOR]

In this paper, we develop pixels with concentric-photogates for applications in time-of-flight 3-D image sensors with single-tap architecture. The pixel uses a buried-channel device and features a reduced effective electron transit length, for the rapid transfer of a signal electron. A reduction in the interpixel irregularity of signal levels and a consequent increase in the demodulation signal amplitude are observed in the single-tap operation mode as opposed to the multitap operation mode. Specifically, we are able to achieve a demodulation contrast higher than 50% from 20 MHz modulation of an 850 nm light-emitting diode illumination. Finally, we construct a sensor composed of 198\,\times\,108 concentric photogate pixels, each with a pitch of 28 \mum, and use it to generate a 3-D image conveying gross distance information and detailed object features with a distance error of less than 1% over a range of 1 to 7 m. [ABSTRACT FROM PUBLISHER]

This paper presents the face-based gradient smoothing point interpolation method (FS-PIM), a numerical method derived from the PIM that solves 3-D boundary value problems. FS-PIM is supported by the theory of G-space, weakened-weak formulations and the gradient smoothing operation. The method is applied in the analysis of electrostatic problems. The obtained results show that both convergence rate and accuracy of the approximation generated by FS-PIM are better than the ones presented by the finite element method, indicating that the technique is suitable for electromagnetic applications. [ABSTRACT FROM AUTHOR]

3-D integration using through-silicon-vias (TSVs) is emerging as one of the key technology options for continued miniaturization. However, because of increased device and current density, the reliability of the 3-D power grid and its integrity must be studied and analyzed. Due to the geometry of TSVs and connections to the global power grid, significant current crowding can occur. Current densities at these connections can be much higher than the expected average values, so extra care is required for accurate analysis. In prior work, TSVs are modeled as single resistors along with power grid wire segments. Such models do not capture detailed current density distribution and may miss hotspots associated with current crowding. This paper studies current crowding and its impact on 3-D power grid integrity. First, we explore the current density distribution within a TSV and its connections to the global chip power grid. Second, we implement simple TSV models to obtain current density distributions within a TSV and its local environment. These models are checked for accuracy by comparing with models simulated using finite element modeling methods. Finally, the simple TSV models are integrated with the global power grid for detailed chip-scale power analysis. [ABSTRACT FROM PUBLISHER]

To facilitate the broadband modeling of integrated electronic and photonic systems from static to electrodynamic frequencies, we propose an analytical approach to study the rank of the integral operator for electromagnetic analysis, which is valid for an arbitrarily shaped object with an arbitrary electric size. With this analytical approach, we theoretically prove that for a prescribed error bound, the minimal rank of the interaction between two separated geometry blocks in an integral operator, asymptotically, is a constant for 1-D distributions of source and observation points, grows very slowly with electric size as square root of the logarithm for 2-D distributions, and scales linearly with the electric size of the block diameter for 3-D distributions. We thus prove the existence of an error-bounded low-rank representation of both surface- and volume-based integral operators for electromagnetic analysis, irrespective of electric size and object shape. Numerical experiments validated the proposed analytical approach and the resultant findings on the rank of integral operators. This paper provides a theoretical basis for employing and further developing low-rank matrix algebra for accelerating the integral-equation-based electromagnetic analysis from static to electrodynamic frequencies. [ABSTRACT FROM PUBLISHER]

Scaling challenges with NAND flash have forced manufacturers to consider monolithic 3-D process and device architectures as potential successor technologies. Those that involve a vertical cylindrical channel are regarded as favorites. These include bit-cost scalable (BiCS) NAND, pipe-shaped bit-cost scalable (p-BiCS) NAND, and terabit cell array transistor (TCAT) NAND. It has been assumed that their manufacturing costs decrease monotonically with the number of additional device layers. This paper presents a rigorous analysis of this assumption based on recently reported challenges associated with the construction of these architectures. It is shown that there is a minimum in die cost after which costs increase with increasing device layers. Also, achievable die sizes using these approaches may not even reach existing production NAND Flash. An important consequence is that monolithic 3-D approaches that involve more lithography-intensive steps may actually result in lower total cost provided that these scale appropriately [ABSTRACT FROM AUTHOR]

Depth image-based rendering is an important technique for virtual view synthesis with limited 3-D data. However, occluded areas result in disocclusions in synthesized images. Filling of the disocclusions in a plausible manner is a critical task in virtual view synthesis. In addition to spatial consistency, temporal consistency of the filled regions also affects the visual quality. In this paper, we propose a novel codebook method called sprite cell for filling the disocclusions with high spatial and temporal consistency. Each codeword consists of a color vector, depth value, frame log, and the confidence score of the corresponding pixel. In contrast with the existing methods that reuse the filling results of previous frames without considering their accuracy, the proposed method estimates the confidence scores of the filling results to prevent temporal continuation of filling errors. Moreover, we introduce a method to correct the luminance of filled disocclusions that compensates for the change of scenes. The experimental results show that the proposed method achieves both objective and subjective improvements over the state-of-the-art methods. The sequences synthesized with the proposed method have higher spatio-temporal consistency. [ABSTRACT FROM PUBLISHER]

The technology of through silicon via (TSV) is one of the most promising enablers for 3-D integrated circuit (IC) integration. The embedded TSVs in silicon chips would, however, cause the problem of carrier mobility changes in surrounding devices. There are two objectives in this paper. The first objective is to numerically and experimentally investigate the effect of via-middle Cu TSV on the mobility change of metal–oxide–semiconductor transistors in the wafer-level silicon chips for this 3-D IC integration. The second objective is to further determine the keep-out zone (KOZ) in terms of the key parameters such as the SiO2 layer effect, the zero-stress temperature, the single and array vias, the through and blind vias, silicon material properties, as well as the diameter and pitch of vias. KOZs based on the >10\% change in carrier mobility are identified by finite element numerical calculations associated with the corresponding piezoresistance coefficients. The numerical results of the changes in saturated current are experimentally validated with good agreements. With the results of detailed analyzes using this validated model, the key parameters affecting the KOZs are presented and further discussed in detail. [ABSTRACT FROM PUBLISHER]

Optical networks-on-chip (ONoCs) are emerging communication architectures that can potentially offer ultrahigh communication bandwidth and low latency to multiprocessor systems-on-chip (MPSoCs). In addition to ONoC architectures, 3-D integrated technologies offer an opportunity to continue performance improvements with higher integration densities. In this paper, we present a 3-D mesh-based ONoC for MPSoCs, and new low-cost nonblocking 4\,\times\,4, 5\,\times\,5, 6\,\times\,6, and 7\,\times\,7 optical routers for dimension-order routing in the 3-D mesh-based ONoC. Besides, we propose an optimized floorplan for the 3-D mesh-based ONoC. The floorplan follows the regular 3-D mesh topology but implements all optical routers in a single optical layer. The floorplan is optimized to minimize the number of extra waveguide crossings caused when merging the 3-D ONoC to one optical layer. Based on a set of real applications and uniform traffic pattern, we develop a SystemC-based cycle-accurate NoC simulator and compare the 3-D mesh-based ONoC with the matched 2-D mesh-based ONoC and 2-D electronic NoC for performance and energy efficiency. Additionally, we quantitatively analyze thermal effects on the 3-D 8\,\times\,8\,\times\,2 mesh-based ONoC. [ABSTRACT FROM AUTHOR]

A novel 3-D structure for Superjunction (SJ) VDMOS which results in high avalanche energy (EAS) under unclamped inductive switching condition without degrading the ON-state current capability is reported in this paper. The proposed structure fabricated in deep trench technology has segmented n+ source region and strip gate. The novel structure can suppress the hole current path beneath the n+ source region under avalanche breakdown condition because of the p+ region which is located between the segmented n+ source regions. In order to verify the mechanism, numerous 3-D simulations are performed using Sentaurus TCAD. As a result, the measurement shows that the robust deep trench SJ-VDMOS improved the EAS by more than six times compared with the conventional structure. [ABSTRACT FROM AUTHOR]

In this paper, we present a new compact drain-current model for double-gate or triple-gate silicon on insulator (SOI) metal–oxide–semiconductor field-effect transistors, which is based on a physics-based 3-D analysis. Explicit analytical model equations for the height of the potential barrier are derived in closed form from a 3-D model for the channel electrostatics without the need to introduce any fitting parameter. The device current is described by a superposition of a surface-channel current above threshold and a center current in the subthreshold region, accounting for the movement of the most leaky path in the device cross section. Comparison with Technology Computer Aided Design (TCAD) shows a good scalability of the model down to a gate length of 30 nm. Furthermore, the I–V characteristics are compared with measurements and obtain accurate results down to an effective channel length of 53 nm. [ABSTRACT FROM AUTHOR]

The ionized field under HVDC transmission lines is actually a 3-D field with considering the influence of wires sag, towers, up-and-downs on the ground, surrounding buildings and other situations and little of its calculation method has been reported. In this paper, a method to calculate the 3-D ionized field under HVDC transmission lines is proposed based on Deutsch's assumption which is simple, fast, and easy to use and the computation cost of which is low. After the validity of the method is testified, some examples are analyzed and some conclusion are given. [ABSTRACT FROM PUBLISHER]

In this paper key design issues and considerations of a low-cost 3-D Cu-TSV technology are investigated. The impact of TSV on BEOL interconnect reliability is limited, no failures have been observed. The impact of TSV stress on MOS devices causes Vth shifts, further analysis is required to understand their importance. Thermal hot spots in 3-D chip stacks cause temperature increases three times higher than in 2-D chips, necessitating a careful thermal floorplanning to avoid thermal failures. We have monitored for ESD during 3-D processing and have found no events take place, however careful further monitoring is required. The noise coupling between two tiers in a 3-D chip-stack is 20 dB lower than in a 2-D SoC, opening opportunities for increased mixed signal system performance. The impact on digital circuit performance of TSVs is accurately modeled with the presented RC model and digital gates can directly drive signals through TSVs at high speed and low power. Experimental results of a 3-D Network-on-Chip implementation demonstrate that the NoC concept can be extended from 2-D SoC to 3-D SoCs at low area (0.018 \ mm^2) and power (3%) overhead. [ABSTRACT FROM AUTHOR]

Closed-form expressions of the resistance, capacitance, and inductance for interplane 3-D vias are presented in this paper. The closed-form expressions account for the 3-D via length, diameter, dielectric thickness, and spacing to ground. A 3-D numerical simulation is used to extract electromagnetic solutions of the resistance, capacitance, and inductance for comparison with the closed-form expressions, revealing good agreement between simulation and the physical models. The maximum error for the resistance, capacitance, and inductance is less than 8%. [ABSTRACT FROM AUTHOR]

Imminent lateral scaling issues with NAND Flash are forcing manufacturers to consider 3-D process integration to keep single chip memory capacities rising while keeping costs down. In this way, several layers of memory cells are stacked on top of a silicon substrate using a single series of process steps with no material bonding used. This paper presents a general and practical cost model showing the advantages of 3-D process integration together with the main parameters determining the total cost. This model suggests that a mini revolution will soon be upon us consisting of multiprogrammable stacked nonvolatile memory cells in a monolithic chip. [ABSTRACT FROM AUTHOR]

This paper reports the development of a fully 3-D finite-element (FE) design tool for the design of electron guns and collectors called the electron optics simulator (EOS). It is a module of the microwave tube simulator suite (MTSS) developed by the University of Electronic Science and Technology of China. EOS specifically targets problem classes including axisymmetric gun, gridded gun, multibeam gun, and multistage depressed collector. EOS is a steady-state trajectory code, which is a solver of electrostatic field and trajectory that takes into account secondary electrons, space-charge effects, and the external magnetic field. The simulator is dependent on the following two front-end features in MTSS: preprocessing that includes a solid modeling tool and a fully 3-D tetrahedral FE mesh automatic generator, and post-processing for analysis and display of the results. A friendly interface is provided to design, test, optimize, and validate the electron optics systems. The aforementioned theoretical models are discussed in detail in this paper. In the end, some comparisons between simulation and experiment are presented. [ABSTRACT FROM AUTHOR]

This paper describes our use of the ADDIE protocol to design and develop an interactive tutorial for students learning molecular symmetry operations and point groups. The tutorial provides a 3-D environment where students can examine molecules, structures, and symmetry elements. Most such tutorials are connected to courses or instructors in ways that make them difficult for others to use. Our goal was to create a freely available tutorial that would be independent of course, textbook, or instructor but would scaffold student learning of these abstract concepts. A usability study was also conducted in order to assist the designers in creating or improving key features of the tutorial and to determine whether the tutorial would be viewed as valuable to students. We found that students appreciated the features, especially mouse-overs and applets that afforded the opportunity to freely rotate accurate images of molecules. [ABSTRACT FROM AUTHOR]

Extensive growth in functional brain imaging, perfusion-weighted imaging, diffusion-weighted imaging, brain mapping and brain scanning techniques has led tremendously to the importance of cerebral cortical segmentation both in 2-D and 3-D from volumetric brain magnetic resonance imaging data sets. Besides that, recent growth in deformable brain segmentation techniques in 2-D and 3-D has brought the engineering community, such as the areas of computer vision, image processing, pattern recognition and graphics, closer to the medical community, such as to neuro-surgeons, psychiatrists, oncologists, neuro-radiologists and internists. In Part I of this research (see Suri et al [1]), an attempt was made to review the state-of-the-art in 2-D and 3-D cerebral cortical segmentation techniques from brain magnetic resonance imaging based on two main classes: region- and boundary/surface-based. More than 18 different techniques for segmenting the cerebral cortex from brain slices acquired in orthogonal directions were shown using region-based techniques. We also showed more than ten different techniques to segment the cerebral cortex from magnetic resonance brain volumes using boundary/surface-based techniques. This paper (Part II) focuses on presenting state-of-the-art systems based on the fusion of boundary/surface-based with region-based techniques, also called regional-geometric deformation models, which takes the paradigm of partial differential equations in the level set framework. We also discuss the pros and cons of these various techniques, besides giving the mathematical foundations for each sub-class in the cortical taxonomy. Special emphasis is placed on discussing the advantages, validation, challenges and neuro-science/clinical applications of cortical segmentation. [ABSTRACT FROM AUTHOR]