A multi-object image segmentation C–V model based on region division and gradient guide

The Chan–Vese (C–V) model is an ineffective method for processing images in which the intensity is inhomogeneous. This is especially true for multi-object segmentation, in which the target may be missed or excessively segmented. In addition, for images with rich texture information, the processing speed of the C–V is slow. To overcome these problems, this paper proposes an effective multi-object C–V segmentation model based on region division and gradient guide. First, a rapid initial contour search is conducted using Otsu’s method. This contour line becomes the initial contour for our multi-object segmentation C–V model based on a gradient guide. To achieve the multi-object segmentation the image is then converted to a single level set whose evolution is controlled using an adaptive gradient. The feasibility of the proposed model is analyzed theoretically, and a number of simulation experiments are conducted to validate its effectiveness.     

A restoration–segmentation algorithm based on flexible Arnoldi–Tikhonov method and Curvelet denoising

In this paper, we illustrate a two-stage algorithm consisting of restoration and segmentation to reach binary segmentation from the noisy and blurry image. The results of our method can be applied in main fields of the image processing such as object extraction. In the first stage, we have a linear discrete ill-posed problem with a noise-contaminated right-hand side, arising from the image restoration. We consider problems in which the coefficient matrix is the sum of Kronecker products of matrices and present a global flexible Arnoldi–Tikhonov method coupled with the generalized cross-validation for the computation of the regularization parameter at each iteration. The proposed algorithm is based on the global Arnoldi method that allows using a more flexible solution subspace. In the second stage, we segment the restored image in order to reach a binary image in which the target object is emphasized. In our segmentation method, we use Gaussian scale-space technique to compute discrete gradients of the restored image for pre-segmenting. Also, in order to denoise, we use a tight frame of Curvelet transforms and thresholding which is based on the principle obtained by minimizing Stein’s unbiased risk estimate. This algorithm has an iterative part based on the iterative part of TFA (Cai et al. in SIAM J Imaging 6(1):464–486, 2013), but we use eigenvectors of Hessian matrix of image for improving this part. Theoretical properties of the method of both stages and numerical experiments are presented.     

SFFS–SVM based prostate carcinoma diagnosis in DCE-MRI via ACM segmentation

The prostate carcinoma is amongst the most commonly occurring cancers in Taiwanese males. Moreover, it is one of the chief reasons for cancer deaths among Taiwanese men, and early diagnosis of prostate cancer is vital for effective treatment. In this work, a diagnosis model for identifying the prostate carcinoma in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is proposed. The urologists utilize the DCE-MRI as a support mechanism for better diagnosis of the carcinoma development in the prostate. Gadolinium is utilized as the contrast agent for the DCE-MRI data, and it was injected once and the time series data were captured at distinct time intervals of 0, 20, 60, and 100 s correspondingly. Primarily, after pre-processing the DCE-MRI information, the prostate data is segmented by employing the active contour model. Subsequently, 136 features are extracted from the segmented prostrate expanse of the DCE-MRI data, and the relative intensity change curve is computed. Afterward, Fisher’s discriminant ratio and sequential forward floating selection is deployed for choosing ten highly discriminative features. Lastly, the segmented prostate regions are classified into two groups, namely: tumor and normal classes by employing the support vector machine classifier. The experimental results elucidate that the proposed system is superior on the subject of accuracy, sensitivity, and specificity when compared with specific existing methods. Additionally, the proposed system also demonstrates a 94.75% accuracy. Moreover, this signifies the fact that the proposed method for analyzing the DCE data has shown prodigious prospects in the prostate carcinoma diagnosis.

     

Image segmentation based on the Poincaré map method

Active contour models (ACMs) integrated with various kinds of external force fields to pull the contours to the exact boundaries have shown their powerful abilities in object segmentation. However, local minimum problems still exist within these models, particularly the vector field's "equilibrium issues." Different from traditional ACMs, within this paper, the task of object segmentation is achieved in a novel manner by the Poincaré map method in a defined vector field in view of dynamical systems. An interpolated swirling and attracting flow (ISAF) vector field is first generated for the observed image. Then, the states on the limit cycles of the ISAF are located by the convergence of Newton-Raphson sequences on the given Poincaré sections. Meanwhile, the periods of limit cycles are determined. Consequently, the objects' boundaries are represented by integral equations with the corresponding converged states and periods. Experiments and comparisons with some traditional external force field methods are done to exhibit the superiority of the proposed method in cases of complex concave boundary segmentation, multiple-object segmentation, and initialization flexibility. In addition, it is more computationally efficient than traditional ACMs by solving the problem in some lower dimensional subspace without using level-set methods.     

Video frame deletion detection based on time–frequency analysis

With the emergence of diverse multimedia editing software, a great number of edited or tampered video resources appear on the Internet, some of which can mix with the genuine ones. Digital video authenticity is an important step to make the best use of these video resources. As a common video forgery operation, frame tampering can change the video content and confuse viewers by removing or inserting some specific frames. In this paper, we explore the traces created by compression process and propose a new method to detect frame tampering based on the high-frequency features of reconstructed DCT coefficients in the tampered sequences. Experimental results demonstrate that our proposed method can effectively detect frame tampering operation, and accurately locate the breakpoint of frame tampering in the streams.     

Image segmentation based on multi-region multi-scale local binary fitting and Kullback–Leibler divergence

The inhomogeneity of intensity and the noise of image are the two major obstacles to accurate image segmentation by region-based level set models. To provide a more general solution to these challenges and address the difficulty of image segmentation methods to handle an arbitrary number of regions, we propose a region-based multi-phase level set method, which is based on the multi-scale local binary fitting (MLBF) and the Kullback–Leibler (KL) divergence, called KL–MMLBF. We first apply the multi-scale theory and multi-phase level set framework to the local binary fitting model to build the multi-region multi-scale local binary fitting (MMLBF). Then the energy term measured by KL divergence between regions to be segmented is incorporated into the energy function of MMLBF. KL–MMLBF utilizes the between-cluster distance and the adaptive kernel function selection strategy to formulate the energy function. Being more robust to the initial location of the contour than the classical segmentation models, KL–MMLBF can deal with blurry boundaries and noise problems. The results of experiments on synthetic and medical images have shown that KL–MMLBF can improve the effectiveness of segmentation while ensuring the accuracy by accelerating this minimization of this energy function and the model has achieved better segmentation results in terms of both accuracy and efficiency to analyze the multi-region image.     

0.5 V bulk-driven ring amplifier based on master–slave technique

This paper presents a new non-clocked standalone bulk-driven ring amplifier based on master–slave technique that ensures stable operation under process, supply voltage and temperature variations. Unlike the conventional ring amplifier the proposed topology operates without the switched capacitor technique under extremely low supply voltage. The bulk-driven ring amplifier was designed using a triple-well 0.18 µm CMOS technology. The simulation results show a 91 dB gain with 13 μW power dissipation from a 0.5 V supply voltage and the total harmonic distortion was equal to 0.29 %.     

A transient enhanced DVS DC–DC converter based on state trajectory analysis

Dynamic voltage scaling (DVS) can effectively reduce energy consumption by dynamically varying the supply voltage of the system accordingly to the clock frequency. A new DVS-enabled DC–DC converter is presented in this paper. State trajectory is employed to analyze the transient features of PWM and PFM Buck converters. A novel transient enhancement circuit is designed to improve the transient response of the DVS-enabled Buck converter. To further expand the output voltage range of the converter, a current-starved voltage controlled delay line is proposed in the controller of DC–DC converter to obtain an ultra low voltage of 0.5 V. When the input voltage is 3.3 V, the output voltage of the converter can be dynamically regulated from 0.5 to 2.0 V. The output voltage tracking speed is less than 7.5 μs/V and the recovery speed is 33 μs/A for a load current step from 0.6 to 0.2 A at output voltage of 0.5 V. The chip area is 1.75 mm × 1.33 mm in a 0.18 μm standard CMOS process.     

Time-domain analysis of lossy multiconductor transmission lines based on the Lax–Wendroff technique

Taking advantage of the hyperbolic characteristics of the telegrapher equations, this paper applies the Lax–Wendroff technique, usually used in fluid dynamics, to transmission line analysis. A second-order-accurate Lax–Wendroff difference scheme for the telegrapher equations for both uniform and nonuniform transmission lines is derived. Based on this scheme, a new method for analyzing lossy multiconductor transmission lines which do not need to be decoupled is presented by combining with matrix operations. Using numerical experiments, the proposed method is compared with the characteristic method, the fast Fourier transform (FFT) approach, and the Lax–Friedrichs technique. With the presented method, a circuit including lossy multiconductor transmission lines is analyzed and the results are consistent with those of PSPICE. The nonlinear circuit including nonuniform lossy multiconductor transmission lines is also computed and the results are verified by HSPICE. The proposed method can be conveniently applied to either linear or nonlinear circuits which include general transmission lines, and is proved to be efficient.     

Two-peak capacitance–voltage behavior in devices based on electron transport materials

Two peaks are observed in the capacitance–voltage (C–V) characteristics of electron-transport fullerene (C₆₀ or C₇₀)/Bphen based devices. The experimental results suggest that the mobile carriers generated from unintentional doping and trapped carriers are the origins of these two peaks, just the same as those of hole-transport devices. In addition, the polarity of one C–V peak voltage (the voltage corresponding to the peak capacitance) reverses as the Bphen layer thickness increases. The transient photo-voltage (TPV) signals show a polarity reversal of the internal electric field, confirming the related phenomenon.     

Design and analysis of firewall-penetrated scheme based on trusted host

On the basis of various firewall-penetrated technologies, a novel firewall-penetrated technology based on trusted host, which can realize the communication between penetrating host and protected host, is proposed in this paper. Meanwhile, the firewall-penetrated evaluating model and its formalized statement is also proposed by quantizing penetrated level, penetrated quality, and penetrated hiding. Finally, the firewall-penetrated technology based on trusted host is analyzed under the firewall-penetrated evaluating model, and the experimental results show that this technology has obvious penetrating effect and high penetrating quality.     

Interfaces analysis by impedance spectroscopy and transient current spectroscopy on semiconducting polymers based metal–insulator–semiconductor capacitors

Impedance and transient current measurements on metal–insulator–semiconductor (MIS) capacitors are used as tools to thoroughly investigate the bulk and interface electronic transport properties of semiconducting polymers, i.e. poly(3-hexylthiophene) (P3HT). Distinct features were observed at both interfaces, i.e. metal–semiconductor and semiconductor–insulator. The results revealed a dispersive transport in the bulk due to the band tail of the localized states, presence of interface states at the interface between the insulator and the semiconductor and formation of a less conductive small layer at the interface semiconductor–metal contact due to intrusions of sputtered Au particles. Effects of self-assembled monolayers (SAMs) treatments of the gate insulating dielectric were investigated showing that treating the gate dielectric with either ozone or hexamethyldisilazane (HMDS) or octyltrichlorosilane (OTS) alter not only the interface semiconductor–insulator but the bulk properties as well. An exponential density of states with a width parameter of 38–58 meV depending on the surface treatment was found to be representative of the band tail of P3HT. Though both OTS and HMDS treatments slightly increase the density of interface states, only OTS treated samples showed a decrease in disorder parameter of the bulk. The latter fact can be attributed to an increase of the grain size due to a favored π-π stacking film growth. An outcome explaining the already reported increase of the lateral mobility and decrease of the vertical mobility observed upon OTS treatment of the gate insulating dielectric in poly(3-hexylthiophene) based devices.     

Fault diagnosis technology based on Wigner–Ville distribution in power electronics circuit

Based on Wigner–Ville distribution similarity, a method of fault diagnosis is proposed for power electronics circuits. After setting up the module time–frequency matrices of Wigner–Ville distribution for all fault signals, the similarities between the module time–frequency matrices of the fault signal and the former standard are then calculated, thus arriving at the diagnosis according to the principle of maximum similarity. The simulation result of fault diagnosis of a thyristor in a three-phase full-bridge-controlled rectifier shows that the method can accurately identify the fault types as well as the location of the fault elements for power electronics circuits, and it has an excellent performance for noise robustness and calculation complexity. Therefore, it is quite practically valuable in the solution to the fault problems for power electronics circuits.     

Microstrip antenna–generator based on gallium arsenide

A design of the microstrip antenna with an epitaxial structure used as a dielectric substrate is developed. The epitaxial structure contains a thin layer of n-type gallium arsenide of on a GaAs semi-insulating substrate. The layer thickness is selected with consideration for the carrier depletion region that appears at the interface between the metal layer, which forms the antenna, and the doped semiconductor layer. We demonstrated experimentally the possibility of application of this design as a FET antenna–generator in a frequency range of 10–15 GHz.     

DVFS-aware motion estimation design scheme based on bandwidth–rate–distortion optimization in application processor systems

In this paper, a novel dynamic voltage–frequency scaling-aware (DVFS-aware) bandwidth- efficient motion estimation (ME) scheme is presented for mobile application processor (AP) systems. Under volatile operating performance conditions due to the power management mechanism, we model the coding bandwidth (BW) and coding performance for the video processor as a convex function of the working frequency. In this paper, we present a bandwidth–rate–distortion (B–R–D) optimized framework that will guarantee the smallest possible rate–distortion cost among coding BW constraints applied in video coding design. By formulating the coding bandwidth-constrained ME problem as an optimization problem, known convex optimization theory can be applied to yield optimal resource-constrained compression. Using varied CIF (352×288)- and HP (1280×720)-sized video sequences with different motion activities over our proposed DVFS-aware video coding approach, the excellent results in terms of coding performance and coding bandwidth savings are obtained. With negligible quality loss, the proposed scheme under coding BW constraints achieves 45–65% coding BW usage reduction over HD-sized 30 frame/s video coding.     

An optimized content delivery approach based on demand–supply theory in disruption-tolerant networks

Telecommunication Systems - Disruption-tolerance networks (DTNs) are suitable for applications that may lack continuous network connectivity. Examples of such applications include coupon...     

Investigation on the mechanism of charge generation in organic heterojunctions: Analysis of I–V and C–V characteristics

The charge generation mechanism of organic heterojunction (OHJ) consisted of 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN) and different hole transporting materials (HTMs) are studied systematically by current-voltage (I–V) and capacitance-voltage measurements. The analysis of I–V characteristics of the devices based on OHJs at forward and reverse voltages by comparing the thickness of HTM layers finds that a forward and reverse symmetrical I–V curve is observed at thin HTM layers and the forward current becomes larger than the reverse current with the increase of HTM thickness, fully illustrating the effectiveness of OHJ charge generation. Moreover, the I–V characteristics at different temperatures indicate that the efficient charge generation is originated from electron tunneling rather than diffusion. And the C–V and capacitance-frequency (C–F)characteristics further illustrate the highly efficient charge generation ability of OHJs so that the charge density is as high as 4.5 × 10¹⁷ cm⁻³, guaranteeing the high conductivity of OHJs, which is very beneficial to developing highly efficient OLEDs using OHJs as charge injector and generator.     

Modeling and analysis of self-similar traffic source based on fractal-binomial-noise-driven Poisson process

~~Modeling and analysis of self-similar traffic source based on fractal-binomial-noise-driven Poisson process1. Will E L, Murad S T, Walter W, et al. On the self-similarity nature of Ethernet traffic (extended version). IEEE/ACM Transactions on Networking…     

Heterostructures in III–V optoelectronic devices

Heterojunctions are used in most III–V optoelectronic devices. Through their use a number of additional degrees of freedom are introduced as compared with homojunction devices. Moreover, new effects, not possible with homojunctions, appear and are applied in many new devices. A classification of heterojunctions is made and their advantages are discussed. The application of heterojunctions in laser diodes is described in some detail.