一种针对约束问题改进的人工蜂群算法

人工蜂群算法是基于自然界蜂群行为的一种算法,该算法已被广泛应用在不同的约束类问题,它能有效解决0-1背包等约束问题。文中提出了基于可行规则和多目标优化问题的改进人工蜂群算法。针对人工蜂群算法存在收敛速度低的缺点,提出一种针对约束问题改进的人工蜂群算法,通过改变一些参数提高算法的收敛速度。对著名的13个约束问题进行试验验证,实验表明改进的人工蜂群算法的最优解和平均解都优于原始的人工蜂群算法。     

一种基于ABC的量子神经网络训练算法

传统的量子神经网络的训练方法容易使得算法陷入局部极小值,将Artificial Bee Colony(ABC)算法引入到原训练算法中,并且对人工蜂群算法进行改进.利用改进后的人工蜂群算法来优化传统量子神经网络,使优化后的量子神经网络具有结构简单、参数少、收敛速度快和可跳出局部极小值等优点.实验结果表明,相比原训练算法该优化算法提高了量子神经网络收敛解的精度.     

GWO与ABC的混合优化算法及其聚类优化

灰狼优化算法（Grey Wolf Optimizer,GWO）和人工蜂群算法（Artificial Bee Colony,ABC）是两种流行且高效的群智能优化算法.GWO具有局部搜索能力强等优势,但存在全局搜索能力弱等缺陷;而ABC具有全局搜索能力强等优点,但存在收敛速度慢等不足.为实现二者优势互补,提出了一种GWO与ABC的混合算法（Hybrid GWO with ABC,HGWOA）.首先,使用静态贪心算法替代ABC雇佣蜂阶段中的动态贪心算法来强化探索能力,同时为弥补其收敛速度降低的不足,提出一种新型的搜索蜜源方式;然后,去掉影响收敛速度的侦查蜂阶段,在雇佣蜂阶段再添加反向学习策略,以避免搜索陷入局部最优;最后,为了平衡以上雇佣蜂阶段的探索能力,在观察蜂阶段,自适应融合GWO,以便增强开采能力和提高优化效率.大量的函数优化和聚类优化的实验结果表明,与state-of-the-art方法相比,HGWOA具有更好的优化性能及更强的普适性,且能更好地解决聚类优化问题.     

基于改进人工蜂群算法的无人机的航迹规划

针对无人机飞行任务规划系统中的航迹规划问题,提出了一种改进的人工蜂群算法,将其应用于无人机的航迹规划。该算法将航迹规划问题转换成函数优化问题,以蜂群为搜索单位,通过群体之间的信息交流与优胜劣汰机制,使蜂群向更优方向进化。在雇佣蜂搜索阶段采用自适应搜索策略来加快算法收敛速度;在跟随蜂搜索阶段引入一种新的概率选择方式来保证种群的多样性;在侦察蜂搜索阶段利用混沌搜索算子提高算法的全局搜索能力。通过标准函数测试与航迹规划仿真对改进后的算法进行验证,结果表明,改进后的算法提高了全局收敛能力,在收敛速度和精度上优于传统的人工蜂群算法,可有效解决无人机的航迹规划问题。     

基于改进人工蜂群算法的认知抗干扰智能决策技术研究

在认知抗干扰系统中,智能决策是其核心,根据干扰环境,对系统的干扰抑制方式、频谱资源分配、调制编码方式和功率调整信息进行最优决策。人工蜂群算法（Artificial Bee Colony,ABC）相较于其他群体智能算法全局寻优速度更快,设置参数少、灵活,易与其他技术结合改进原算法,实用性更广泛,但ABC算法同样有其局限性,如局部搜索能力较弱、后期收敛速度慢等。针对复杂干扰环境下对离散参数的决策,本文设计了一种基于改进人工蜂群算法的认知抗干扰智能决策引擎,分析了引擎模型,根据系统效能设计了目标函数和染色体,阐述了决策实现步骤,优化了决策参数,提出了按基因组搜索的改进算法;通过对系统抗干扰性能的仿真,验证了与未采用智能决策的抗干扰系统相比,采用本文提出的智能决策引擎的认知抗干扰系统在干扰环境中不仅具有强抗干扰性能,而且在保证通信传输可靠性的前提下,具有较低的发射功率和高传输效率,与采用传统人工蜂群算法和遗传算法的决策引擎相比,基于改进人工蜂群算法的决策引擎平均收敛代数更少且最优解概率更高。      

基于混沌鲶鱼效应的人工蜂群算法及应用

针对目前人工蜂群算法的早熟收敛、陷入局部极值等问题,提出一种基于混沌鲶鱼效应的改进人工蜂群算法.首先,采用随机性更高的混沌序列初始化蜂群以扩大其遍布范围;其次,集成了鲶鱼效应和混沌理论提出了混沌鲶鱼蜂,并引入了它与跌入局部极值的蜂群之间的有效竞争协调机制,从而增进蜜蜂群体跳出局部最优解、加速收敛的能力.支持向量机的学习能力主要取决于其惩罚因子C和核函数参数的合理选择,对其参数的优化可以提升其学习效果,然而现行算法均存在一定局限性.基于我们提出的改进人工蜂群算法,对支持向量机的参数进行了优化.最后,在UCI（加州大学欧文分校）数据集和行为识别真实数据集上进行了测试,验证基于改进人工蜂群算法的支持向量机具有更强的分类性能.     

基于差分变异算子的改进人工蜂群算法

文章针对传统人工蜂群算法收敛速度慢、精度不高的问题,基于差分进化算法中的变异算子,对人工蜂群算法搜索方程进行改进,在种群更新过程中引入当前种群最优个体信息,以提升算法的收敛速度和局部优化能力。     

基于改进人工蜂群算法的认知无线电频谱分配

各类无线电业务的兴起和发展使得频谱资源处于拥挤的状态,然而当前的静态频谱分配机制导致频谱资源存在着部分频段紧缺和频谱利用不平衡的矛盾。认知无线电是一种提高频谱利用率的新技术。认知无线电系统中，动态频谱分配技术在利用闲置频谱资源上发挥关键作用。本文介绍了频谱分配的图论着色模型，提出一种改进的蜂群算法。基本人工蜂群算法存在搜索精度不高和收敛速度较慢的问题，本文改进的人工蜂群算法引入了基于差分进化算法的搜索策略和高斯变异的侦察策略，并且对选择策略进行改进，提高了种群的多样性。将改进的蜂群算法应用于频谱分配模型中，实验结果表明：改进的人工蜂群算法可以得到更好的系统收益，加快了收敛速度。     

基于混合人工蜂群策略的改进DV-Hop定位算法

为了减小DV-Hop算法在无线传感器网络节点定位中的误差,提出了一种基于混合人工蜂群算法的改进算法。该算法结合了粒子群算法收敛速度快和蜂群算法搜索能力强的特性,首先通过DV-Hop算法估计锚节点与未知节点之间的距离,然后采用粒子群算法计算未知节点的初始位置,最后利用蜂群算法进行迭代求精,从而实现基于不同距离测量方法的总体优化。仿真结果表明,改进算法的定位精度较DV-Hop算法和基于粒子群的定位算法有明显改善。     

一种基于人工蜂群的高维非线性优化算法

针对传统优化算法在求解高维非线性优化问题时,存在收敛速率慢和求解精度不高等问题.提出一种改进的人工蜂群优化算法.正交试验设计算法被用于初始化蜂群和侦察蜂探索新蜜源.采蜜蜂利用高斯分布估计优化算法在蜜源附近搜索,跟随蜂采用自适应差分算法进行搜索.最后,通过4个标准的高维Benchmark函数测试表明,本文算法在收敛速度、求解精度和稳定性方面有一定优势.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

Call for Papers

正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its