共查询到20条相似文献,搜索用时 0 毫秒
1.
This paper introduces a novel approach for denoising the images corrupted by impulsive noise (IN) by using a new nonlinear IN suppression filter, entitled k-nearest neighborhood pixels-based Adaptive-Fuzzy Filter (k-AFF). The proposed filter is based on statistical impulse detection and nonlinear filtering which uses Adaptive-Network-Based Fuzzy Inference System (ANFIS) as a missed data interpolant over the k-nearest neighbor pixels of the corrupted pixels. The impulse detection is realized by using the well-known Kolmogorov–Smirnov-based goodness-of-fit test, which yields a decision about the impulsivity of each pixel. To demonstrate the capability of k-AFF, extensive simulations were realized revealing that the proposed filter achieves a better performance than the other filters mentioned in this paper in the cases of being effective in noise suppression and detail preservation, even when the images are highly corrupted by IN. 相似文献
2.
In this paper, we use both J-divergence and Bhattacharyya coefficient as distance measures to optimize a parallel distributed detection system consisting of N local detectors and a global decision maker. The optimization is obtained by allowing the thresholds of the local detectors to be functions of the global probability of false alarm. Numerical results for the case of four and six local detectors are obtained. These results indicate the superiority of our approach over those reported in the literature in which the local thresholds were specified without taking the level of global probability of false alarm into account. 相似文献
3.
C.R. Flüchter A. de Siervo D. Weier M. Schürmann U. Berges S. Dreiner M.F. Carazzolle R. Landers G.G. Kleiman C. Westphal 《Materials Science in Semiconductor Processing》2006,9(6):1049
Due to the ongoing miniaturization of semiconductor devices new gate dielectrics are required for future applications. In this work we investigated hafnium silicide as a pre-system for hafnium oxide, one of the most promising candidates. One of the major problems of HfO2-films on silicon is the formation of hafnium silicide at the HfO2/Si interface. Therefore, ultrathin films of the system HfSi on with a systematic varied thickness from 3 to 30 Å were prepared. Measurements were conducted by means of X-ray photoelectron spectroscopy and low energy electron diffraction (LEED). Also full 2π X-ray photoelectron diffraction (XPD) patterns with high spectral resolution were recorded. Against other reports related to thicker films, several heating cycles showed no phase transitions of the ultrathin films. However, above temperatures of an island formation is strongly indicated. The experimental XPD patterns are compared to simulated patterns of model structures. For the first time we present a modification of the C49 structure a possible structure for ultrathin HfSi2-films on bulk Si. As an outlook possibilities for preparing the system are introduced. 相似文献
4.
Dynamic establishment of restorable connections in WDM networks is an important problem that has received much study. We propose a dynamic restorable connection establishment scheme that uses p-cycles to protect a connection’s working lightpath. For a given connection request, our scheme first computes a working lightpath and then computes a set of p-cycles to protect the links on the working lightpath so that the connection can survive any single link failure. The key advantage of the proposed scheme is that it enables fast failure recovery while requiring very simple online computation at connection establishment time. Our scheme consists of three components for connection establishment: offline computation of primary cycles, online computation of the working lightpath, and online computation of p-cycles for working lightpath protection. Our scheme also includes a connection teardown procedure that computes and releases all p-cycles that are no longer needed. Simulation study shows that our scheme significantly outperforms an existing p-cycle-based dynamic restorable connection establishment scheme. 相似文献
5.
An increasing number of standards in wireless communications have encouraged to study programmable processors as platforms for flexible receivers. A multiple-input multiple-output (MIMO) antenna system combined with orthogonal frequency division multiplexing (OFDM) technique has been introduced in many wireless communications standards, such as in the third generation long term evolution (3G LTE). The MIMO-OFDM system requires an efficient detector and a platform support for parallel processing of multiple subcarriers. A K-best list sphere detector (LSD) provides for near optimal decoding performance and a fixed throughput making it an interesting algorithm from the point of view of practical implementations.In this paper, we compare the implementations of the K-best LSD on four processor platforms: a digital signal processor (DSP), software defined radio (SDR), application-specific processor (ASP) and application-specific instruction-set processor (ASIP). The DSP is a popular very long instruction word (VLIW) device (TMS320C6455), the SDR processor employs multithreading and multiple cores (SB3500 core processor), the ASP is based on transport triggered architecture (TTA), while the ASIP is the SDR processor enhanced with a special instruction-set extension for sorting.A 2×2 MIMO antenna system with 64-quadrature amplitude modulation (64-QAM) is assumed. The chosen list sizes K=8 and 16 are based on simulation results carried out in MATLAB environment with the third generation long term evolution (3G LTE) parameters. The proposed ASIP achieved a promising throughput of 32.0 Mbps, where the software defined radio (SDR) implementation on the SB3500 core processor suffers from an inefficient software sorter. The ASP, in which the minimized hardware complexity has been the goal, achieves a throughput of 7.6 Mbps. However, more essential examination is related to the symbol time, which sets strict parallel processing requirements to the programmable processors. 相似文献
6.
The recently reported inverse silver oxide phase of SiO2 possesses a high dielectric constant as well as lattice constant compatibility to Si. We explore the closely related oxides, GeO2, SnO2 with the same inverse silver oxide structure using ab initio density functional theory within the local density approximation (LDA). According to the phonon dispersion curves, both these structures are computed to be unstable. On the other hand, their alloys Si0.5Ge0.5O2, Si0.5Sn0.5O2, and Ge0.5Sn0.5O2 are stable with higher dielectric constants than that of SiO2 in the same phase. Their first-principles elastic constants, electronic band structures and phonon dispersion curves have been obtained with high precision. 相似文献
7.
Giulio Ferrari J.R. Watling S. Roy J.R. Barker P. Zeitzoff G. Bersuker A. Asenov 《Materials Science in Semiconductor Processing》2006,9(6):995
HfO2-based high-κ dielectrics are among the most likely candidates to replace SiO2 and the currently favoured oxinitride in the next generation of MOSFETs. High-κ materials allow the use of a thicker gate dielectric, maintaining the gate capacitance with reduced gate leakage. However, they lead to a fundamental mobility degradation due to the coupling of carriers to surface soft (low-energy) optical phonons. Comparing the vertical field dependence of the mobility for HfO2 and SiO2, the severe degradation in mobility in the presence of high-κ becomes evident. The introduction of a SiO2 interfacial layer between the channel and the HfO2 mitigates this degradation, by increasing the effective distance between the carriers and the SO phonons, thus decreasing the interaction strength, this does though lead to an increase in the equivalent oxide thickness (EOT) of the gate dielectric. The material of choice for the first commercial introduction of high-κ gate stacks is Hafnium Silicate (SixHf1-xO2). This alloy stands up better to the processing challenges and as a result suffers less from dielectric fluctuations. We show that as the fraction of Hf increases within the alloy, the inversion layer mobility is shown to decrease due to the corresponding decrease in the energy of the surface optical phonons and increase in the dielectric constant of the oxide. 相似文献
8.
9.
k 《Solid-state electronics》2008,52(6):849-856
We present the hole subband structure calculation in single and double p-type δ-doped quantum wells in Si based on the 4×4 Luttinger–Kohn Hamiltonian. The valence band bending and the Γ hole states are calculated within the lines of the Thomas–Fermi–Dirac approximation and the effective mass theory at the Brillouin zone center. The obtained zone center eigenstates are then used to diagonalize the k·p Hamiltonian for non-zero k. The hole subband structure is analyzed as a function of the impurity density and the distance between δ wells. It is shown that the application of a 4×4 model to describe the hole ground state in single p-type δ-doped in Si can be misleading. 相似文献
10.
This paper is concerned with the partially mode-dependent H∞ filtering problem for discrete-time Markovian jump systems with partly unknown transition probabilities via different techniques, where the unknown elements are estimated. New version of bounded real lemma for discrete-time Markovian jump systems with partly unknown transition probabilities is presented. Based on the obtained criterion and via a stochastic variable satisfying Bernoulli random binary distribution, new H∞ filter with partially mode-dependent characterization is established in terms of linear matrix inequalities (LMIs). Finally, numerical examples are given to show the effectiveness of the proposed design method. 相似文献
11.
12.
m 《AEUE-International Journal of Electronics and Communications》2008,62(9):715-716
An explicit expression is derived for the symbol error rate (SER) of the star MQAM system considered by Ioannis and Aris [Closed-form SER expressions for star MQAM in frequency non-selective Rician and Nakagami-m channels. Int J Electron Commun AEU 2005;59:417–20]. 相似文献
13.
Abdel-Ouahab Salem Jean-Christophe Thierry 《AEUE-International Journal of Electronics and Communications》2009,63(9):728-735
In this paper, some useful properties of cross-ΨB-energy operator, which measures the interaction between two signals, are provided. We show that ΨB is a generalization of some extensions of Teager–Kaiser operator to complex signals. Due to its bilinearity, ΨB satisfies the quadratic superposition principle. We point out the link between the ΨB and the Lie bracket, which measures the instantaneous differences in the relative change between two signals. We show how the ΨB operator can handle wideband signals using bandpass filtering. We also show how the quadratic superposition law can be used for detection purpose. 相似文献
14.
The Akaike information criterion, AIC, and its corrected version, AICc are two methods for selecting normal linear regression models. Both criteria were designed as estimators of the expected Kullback–Leibler information between the model generating the data and the approximating candidate model. In this paper, two new corrected variants of AIC are derived for the purpose of small sample linear regression model selection. The proposed variants of AIC are based on asymptotic approximation of bootstrap type estimates of Kullback–Leibler information. These new variants are of particular interest when the use of bootstrap is not really justified in terms of the required calculations. As its the case for AICc, these new variants are asymptotically equivalent to AIC. Simulation results which illustrate better performance of the proposed AIC corrections when applied to polynomial regression in comparison to AIC, AICc and other criteria are presented. Asymptotic justifications for the proposed criteria are provided in the Appendix. 相似文献
15.
Laser ablation of a high purity (99.7%) iron target was used to accomplish the depositions of iron nanoparticles on the (0 0 0 1) face of single crystal sapphire wafers. The nanoparticles were characterized in situ by means of X-ray photoelectron spectroscopy (XPS). The growth mechanism was determined by applying the QUASES-Tougaard methodology to the extended part of the background intensity of the Fe KMM peak in XPS spectra. The heights of nanoparticles obtained are between 3.5 and 6.5 nm. In the first 150 laser pulses, the height of the nanoparticles remained constant while the coverage was increased. 相似文献
16.
We have performed a theoretical study of electronic states and the parallel Landé g-factor in a quantum dot (QD), assumed to be in the form of a pillbox, in the presence of an uniform magnetic field applied parallel to the pillbox axis. The quantum pillbox is assumed to consist of a finite length cylinder of GaAs material surrounded by Ga1-xAlxAs which describe the realistic finite potential confinement. The calculations have been performed by using the Kummer confluent hypergeometric functions. This study is performed for different radii and lengths of the cylindrical GaAs pillbox and the limit cases have been studied to prove the validity of the model. Our results are in good agreement with the previous theoretical results [F.E. López, B.A. Rodríguez, E. Reyes-Gómez, L.E. Oliveira, in press] in the limit geometry of a quantum well wire (QWW). 相似文献
17.
In this work crossed Andreev reflection (CAR) and elastic cotunneling (EC) are studied for junctions (N1ISIN2), where N1 and N2 are normal metals, S is a high Tc superconductor and I is an insulator. This study is carried out based on the analytical solutions of Bogoliubov de Gennes equations for anisotropic superconductors. The influence of different pair potential symmetries on the CAR and crossed conductance is analyzed. We show that CAR and EC are higher in dx2-y2 symmetry than in s symmetry. In the case of normal electrodes without magnetization, EC is the predominantly process for dx2-y2 symmetry, while in s symmetry, both processes decay with the same amplitude. 相似文献
18.
The magnetic and structural properties of the Fe0,70Si0,30 alloy are analyzed by using X-ray diffraction and Mössbauer spectrometry. The samples were prepared by mechanical alloying in a planetary ball mill pulverisette 5 during 1, 5, 9, 15, 75 and 100 h milling, with a ball mass to powder mass relation of 10:1. The X-ray diffraction patterns showed a coexistence of BCC, DO3 and FeSi structural phases; however, for 1-5 h process, we observed additional peaks which correspond to iron and silicon elements. These results indicate us that the alloy is still a non-fully consolidated sample. The grain size decreases drastically from 1 to 5 h, then slowly up to 15 h, and finally it remains nearly constant. The lattice parameter for each phase remains nearly constant (2838 A for the BCC structure). The shape of hyperfine field distributions used to describe the Mössbauer spectra is discussed. 相似文献
19.
The energy loss of hydrogen and helium ions in the low energy range in single crystal gold targets is investigated experimentally. We found that the stopping power for helium ions shows a deviation from the proportionality with ion velocity predicted theoretically. This behavior has been also observed for protons in previous experiments. Additionally, we found that for a small range of velocity the energy loss for helium ions has the same magnitude as for protons for the same velocity. This last finding is in agreement with early theoretical prediction for the ion energy loss interacting with low electron densities, beyond of metallic densities, in the frame of the free electron gas model and the density functional theory. Both effects are explained due to two particular phenomena: particle channeling in monocrystalline targets, where the inhomogeneity of the spatial electron density distribution plays a fundamental role and the well-known threshold effect in the stopping power which is explained considering the electronic band structure properties of metallic targets. 相似文献
20.
The importance of fully coupled and semi-coupled piezoelectric models for quantum dots are compared. Differences in the strain of around 30% and in the electron energies of up to 30 meV were found possible for GaN/AlN dots. 相似文献