后处理在数字抠像中的应用与解析

数字抠像是将一幅图像中的前景物体与背景进行分离的问题,它的关键在于Alpha通道的计算.以往通过采样方法求得的Alpha中,由于采用逐点计算的离散化方式,求解出的Alpha通常不连续,并且包含很多噪声,因而需要对Alpha进行后处理,这不仅会增强Alpha在视觉上的平滑性,而且能够进一步提高Alpha的精确度.在目前国际上,有关数字抠像后处理领域已经进行了许多研究,但缺少相关的综述性文献,并且对后处理后的Alpha如何进行定量的评价也仍未系统解决.本文首先将数字抠像中的后处理方法分为2类:与仿射类方法相结合的方式及自平滑方式,其次,对两类方法进行了全面的总结和梳理,并对方法的优缺点进行了分析,对将来研究方向提出了建议,最后,针对后处理后的Alpha结果进行了全面的量化比较,弥补了传统方法基本上仅在视觉层面上进行比较的缺陷.

Numerical Simulation of Dam Breaking Using Smoothed Particle Hydrodynamics and Viscosity Behavior

Smoothed particle hydrodynamics (SPH) is a Lagrangian meshless particle method. It is one of the best method for simulating violent free surface flows in fluids and solving large fluid deformations. Dam breaking is a typical example of these problems. The basis of SPH was reviewed, including some techniques for governing equation resolution, such as the stepping method and the boundary handling method. Then numerical results of a dam breaking simulation were discussed, and the benefits of concepts like artificial viscosity and position correction were analyzed in detail. When compared with dam breaking simulated by the volume of fluid (VOF) method, the wave profile generated by SPH had good agreement, but the pressure had only reasonable agreement. Improving pressure results is clearly an important next step for research.

A data-driven method to predict future bottlenecks in a remanufacturing system with multi-variant uncertainties

The remanufacturing system is remolding the manufacturing industry by bringing scrapped products back to such a condition that reintegrated performance is just as good as new.The remanufacturing environment is featured by a far deeper level of uncertainty than new manufacturing,such as probabilistic routing files,and highly variable processing time.The stochastic disturbances result in the production bottlenecks,which constrain the productivity of the job shop.The uncertainties in the remanufacturing process cause the bottlenecks to shift when the workshop is processing.Considering this outstanding problem,many researchers try to optimize the production process to mitigate dynamic bottlenecks toward a balanced state.This paper proposes a data-driven method to predict bottlenecks in the remanufacturing system with multi-variant uncertainties.Firstly,discrete event simulation technology is applied to establish a simulation model of the remanufacturing production line and calculate the bottleneck index to identify bottlenecks.Secondly,a data-driven method,auto-regressive moving average(ARMA)model is employed to predict the bottlenecks in the system based on real-time data captured by the Arena software.Finally,the proposed prediction method is verified on real data from the automobile engine remanufacturing production line.

Multi-objective optimization scheduling for new energy power system considering energy storage participation

For the low utilization rate of photovoltaic power generation,taking a new energy power system constisting of concentrating solar power(CSP),photovoltaic power(PP)and battery energy storage system as an example,a multi-objective optimization scheduling strategy considering energy storage participation is proposed.Firstly,the new energy power system model is established,and the PP scenario generation and reduction frame based on the autoregressive moving average model and Kantorovich-distance is proposed.Then,based on the optimization goal of the system operation cost minimization and the PP output power consumption maximization,the multi-objective optimization scheduling model is established.Finally,the simulation results show that introducing energy storage into the system can effectively reduce the system operation cost and improve the utilization efficiency of PP.

Parametric modeling of carbon nanotubes and estimating nonlocal constant using simulated vibration signals-ARMA and ANN based approach

Nonlocal continuum mechanics is a popular growing theory for investigating the dynamic behavior of Carbon nanotubes(CNTs).Estimating the nonlocal constant is a crucial step in mathematical modeling of CNTs vibration behavior based on this theory.Accordingly,in this study a vibration-based nonlocal parameter estimation technique,which can be competitive because of its lower instrumentation and data analysis costs,is proposed.To this end,the nonlocal models of the CNT by using the linear and nonlinear theories are established.Then,time response of the CNT to impulsive force is derived by solving the governing equations numerically.By using these time responses the parametric model of the CNT is constructed via the autoregressive moving average(ARMA)method.The appropriate ARMA parameters,which are chosen by an introduced feature reduction technique,are considered features to identify the value of the nonlocal constant.In this regard,a multi-layer perceptron(MLP)network has been trained to construct the complex relation between the ARMA parameters and the nonlocal constant.After training the MLP,based on the assumed linear and nonlinear models,the ability of the proposed method is evaluated and it is shown that the nonlocal parameter can be estimated with high accuracy in the presence/absence of nonlinearity.

Analytic Solution to Nonlinear Dynamical System of Dragon Washbasin

Based on phase-plane orbit analysis, the mathematical model of piecewise-smooth systems of multi-degree-of-freedom under the mode coordinate is established. Approximate analytical solution under the physical coordinate of multi-degree-of-freedom self-excited vibration induced by dry friction of piecewise-smooth nonlinear systems is derived by means of average method, the results of which agree with those of the numerical solution. An effective and reliable analytical method investigating piecewise-smooth nonlinear systems of multi-degree-of-freedom has been given. Furthermore, this paper qualitatively analyses the curves about stationary amplitude versus rubbing velocity of hands and versus natural frequency of hands, and about angular frequency versus rubbing velocity of hands. The results provide a theoretical basis for identifying parameters of the system and the analysis of steady region.

Integrated Statistical and Engineering Process Control Based on Smooth Transition Autoregressive Model

Traditional studies on integrated statistical process control and engineering process control (SPC-EPC) are based on linear autoregressive integrated moving average (ARIMA) time series models to describe the dynamic noise of the system.However,linear models sometimes are unable to model complex nonlinear autocorrelation.To solve this problem,this paper presents an integrated SPC-EPC method based on smooth transition autoregressive (STAR) time series model,and builds a minimum mean squared error (MMSE) controller as well as an integrated SPC-EPC control system.The performance of this method for checking the trend and sustained shift is analyzed.The simulation results indicate that this integrated SPC-EPC control method based on STAR model is effective in controlling complex nonlinear systems.

Computational Simulation of Hypervelocity Penetration Using Adaptive SPH Method

The normal hypervelocity impact of an Al-thin plate by an Al-sphere was numerically simulated by using the adaptive smoothed particle hydrodynamics (ASPH) method. In this method, the isotropic smoothing algorithm of standard SPH is replaced with anisotropic smoothing involving ellipsoidal kernels whose axes evolve automatically to follow the mean particle spacing as it varies in time, space, and direction around each particle. Using the ASPH, the anisotropic volume changes under strong shock condition are captured more accurately and clearly. The sophisticated features of meshless and Lagrangian nature inherent in the SPH method are kept for treating large deformations, large inhomogeneities and tracing free surfaces in the extremely transient impact process. A two-dimensional ASPH program is coded with C++. The developed hydrocode is examined for example problems of hypervelocity impacts of solid materials. The results obtained from the numerical simulation are compared with available experimental ones. Good agreement is observed.

The Study on Trade Policy and Openness of Mongolia： Influences on Trade Flows Between China-Mongolia-Russia （Past and Future）

This paper aimed to highlight the effects of conflict in Mongolia on trade policy and openness, by estimating the trade flows with neighbor countries （China and Russia）. Fourteen years＇ （2000-2013） data of Mongolian imports and exports were collected and gone through principal component analysis （PCA） and empirical analysis for grouping various trades with China and Russia. The empirical analysis identified the determining factors of Mongolian trade flow and openness with China and Russia. Empirical analysis evidenced that Mongolian trade and openness policy raised bilateral trade between China and Russia, leaving a great influence on economic size. Two main questions represented as empirically tested by each sample country. How did Mongolian trade policy and openness influence trade flows between China and Russia and economic growth of Mongolia？ Did Mongolian trade policy and the bilateral trade with China and Russia increase on trade openness？ Finally, the study focused on the forecasts from 2016 to 2018 to examine Mongolian trade flows with China and Russia using ordinary least squares method and autoregressive-moving-average （ARMA） model. China-Mongolia-Russia trade flows will continue to dominate during the forecasted period. As shown by the structure of export and import, goods with China and Russia influenced the mutual trade amount. Moreover, China and Russia traded to continue with Mongolia for goods in long run. Trade policy and openness, the major contributor in Mongolian economy, are significantly playing roles in trade and economy.

Changes of Ca^2+ activated potassium channels and cellular proliferation in autogenous vein grafts

Objective: To investigate changes of Ca2+ activated potassium channels (KCa) in autogenous vein grafts. Methods: Contraction of venous ring was measured by means of perfusion in vitro. The intimal rabbits proliferation of vascular and proliferation of cultured smooth muscle cells(vascular smooth muscle cells, VSMCs)were observed by the means of computerised image analysis and MTT method respectively. Furthermore, whole cell mode of patch clamp was used to record KCa of VSMCs isolated from autogenous vein grafts. Results: One week after transplantation there were no significant differences of contraction and intimal relative thickness between autogenous vein grafts and control. Contraction and intimal relative thickness of autogenous vein graft were significantly increased 2 weeks after transplantation (P<0.05, n=8 vs control), and they was more enhanced 4 weeks after vein transplantation (P<0.01, n=8 vs control).TEA(blocker of Ca2+ activated potassium channels)increased MTT A490 nm value of VSMCs from femoral vein in a dose dependent manner(P<0.05, n=8). KCa current density was significantly attenuated in VSMCs from autogenous vein grafts (1-4) week after transplantation(P<0.05, n=5).Conclusion: KCa is inhibited in autogenous vein graft, which account for vasospasm and intimal proliferation.

Effects of extravascular trestle model coated phosphorus radioisotope on intimal hyperplasia in autologous vein grafts

Objective: To design an extravascular trestle model coated phosphorus-32, an isotope radiating beta rays, and investigate its effects on intimal hyperplasia of autologous vein grafts. Methods: ETA cDNA was used as a gene probe specific to vascular SMCs on the basis of in situ hybridization. The femoral veins were transplanted reversely into colateral femoral arteries in rabbits, and the animals were divided into control, chemical agents and phosphorus-32 groups. The morphometry was applied to calculate the ETA cDNA expression and intimal thickness. Spearman correlation method was utilized to investigate their relationship. Results: Intimal thickness in grafts of phosphorus-32 group was markedly reduced. Additionally, intimal ETA gene expression was also decreased in beta rays group. The values increased at a slower rate significantly different from that of control and aspirin groups (P<0.01). The correlation of ETA cDNA expression and intimal thickness exhibited a strongly positive relation. Conclusion: Beta rays in extravascular model could remarkably inhibit intimal thickening and SMC proliferation. The correlation is an indirect evidence indicating that intimal hyperplasia composed of SMCs proliferation. It suggests that ETA cDNA expression could be a quantitative estimation of vascular SMC because of its specifics.

Adaptive preprocessing algorithms of corneal topography in polar coordinate system

New adaptive preprocessing algorithms based on the polar coordinate system were put forward to get high-precision corneal topography calculation results. Adaptive locating algorithms of concentric circle center were created to accurately capture the circle center of original Placido-based image, expand the image into matrix centered around the circle center, and convert the matrix into the polar coordinate system with the circle center as pole. Adaptive image smoothing treatment was followed and the characteristics of useful circles were extracted via horizontal edge detection, based on useful circles presenting approximate horizontal lines while noise signals presenting vertical lines or different angles. Effective combination of different operators of morphology were designed to remedy data loss caused by noise disturbances, get complete image about circle edge detection to satisfy the requests of precise calculation on follow-up parameters. The experimental data show that the algorithms meet the requirements of practical detection with characteristics of less data loss, higher data accuracy and easier availability.

Endothelin-1, an important mitogen of smooth muscle cells of spontaneously hypertensive rats

OBJECTIVE: To study the features of vascular smooth muscle cell (VSMC) proliferation induced by endothelin-1 (ET-1). METHODS: VSMCs of spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats were cultured and treated with ET-1. Basic fibroblast growth factor (bFGF) gene expression was measured using both Northern blot and an enzyme-linked immunoassay. RESULTS: ET-1 resulted in an increase in bFGF transcripts at 8 - 24 h; bFGF levels were significantly higher in VSMCs treated with ET-1 than in those not treated. However, VSMCs growth responses in SHR and WKY were different. Smooth muscle cells of SHR were hyper-responsive to ET-1. Maximal bFGF mRNA levels were elevated 3.5-fold at 4 h of stimulation in WKY and 8-fold at 8h in SHR4. Moreover, the proliferation of VSMCs induced by ET-1 was inhibited by antisense phosphorothioate oligodeoxynucleotides (10 micromol/L AS-bFGF) but not sense bFGF oligomers at the same concentrations, being reduced by 80% in SHR and 40% in WKY vs control, respectively. Furthermore, the effect of AS-bFGF oligomers on SHR SMC proliferation is significantly greater than on WKY SMC proliferation. CONCLUSION: ET-1 may be required for exaggerated vascular growth responses in SHR and bFGF may be involved.

Quasi-equilibrium glide adaptive guidance for hypersonic vehicles

The entry-glide guidance strategy for hypersonic vehicles that can satisfy both terminal and path constraints is investigated in this paper.We propose a quasi-equilibrium glide adaptive guidance methodology based on the quasi-equilibrium glide condition(QEGC),which innovatively utilizes the quasi-equilibrium glide phenomenon in lifting entry.With the aid of QEGC,both range and terminal velocity can be predicted analytically with high precision.The path constraints are converted into angle of attack constraints,which has been difficult to realize by using traditional predictive guidance methods.The algorithm is independent of the standard trajectory.All the guidance commands,including the bank angle and the angle of attack,are calculated analytically in real time,which endows the algorithm with sufficient adapbility.The results of a CAV-H vehicle guidance test show that the algorithm leads the vehicle along a quasi-equilibrium glide trajectory satisfying both the terminal and path constraints and has sufficient flexibility for occasional mission changes.Furthermore,the robustness of the guidance algorithm under disturbances is validated through a Monte Carlo simulation.

Traces of weighted function spaces: Dyadic norms and Whitney extensions

The trace spaces of Sobolev spaces and related fractional smoothness spaces have been an active area of research since the work of Nikolskii, Aronszajn, Slobodetskii, Babich and Gagliardo among others in the 1950's. In this paper, we review the literature concerning such results for a variety of weighted smoothness spaces. For this purpose, we present a characterization of the trace spaces(of fractional order of smoothness),based on integral averages on dyadic cubes, which is well-adapted to extending functions using the Whitney extension operator.

Enabling topical and long-term anti-radical properties for percutaneous coronary intervention-related complications by incorporating TEMPOL into electrospun nanofibers

Scavenging reactive oxygen species(ROS)by antioxidants has been demonstrated as the most effective strategy for preventing percutaneous coronary intervention(PCI)-related complications.However,topical and long-term delivery of ROS antioxidants to a specific vascular tissue is proven to be a great challenge.Herein,an ROS scavenger of 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl(TEMPOL)is incorporated into electrospun nanofibers with a tunable loading amount to achieve its topical applicability and long-term antiradical capability.Biological functions of such TEMPOL-loaded electrospun membranes are evaluated by cell proliferation,ROS-scavenging capability,monocyte adhesion,cell migration,inflammatory molecule secretion and mRNA expression in vitro.After optimizing the loading amount of TEMPOL,such an electrospun membrane presents a superior ROS-scavenging and anti-inflammation performance for both endothelial cells and macrophages.The expression of endothelial prothrombogenic molecules and the migration of vascular smooth muscle cells(VSMCs)are also effectively inhibited.Thus,it is bravely predicted that the topical use of such a TEMPOL-loaded electrospun system will be a promising pathway for the anti-restenosis therapy,especially when used as a novel coating on stent for long-term and topical delivery of antioxidant drugs.