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21.
This paper introduces an evolutionary algorithm, Shuffled Frog Leaping Algorithm (SFLA), to solve the optimization problem in designing the multi-pumped Raman Fibre Amplifier (RFA). SFLA is a powerful optimizer tool because of its efficient mathematical expressions and global search capability. We utilize SFLA to determine the optimal pump wavelengths and pump powers by minimizing the gain ripple of RFA. To accelerate calculations, a terminal value optimization strategy (TVOS) is incorporated into the evolution of SFLA. This proposed strategy takes the terminal power values of pumps as the decision variables in optimization. Then, the optimal original power values of the pumps are obtained by solving the Power Coupled Equations once, without using the traditional method of repetitive guesses.The combination of SFLA and TVOS enhances the efficiency of optimization and accelerates calculation, while satisfying the design requirements of RFA.The simulation results show that nearly 65% of computational time has been saved compared with the traditional average power analysis. The 4-pumped C+L band of backward multi-pumped RFA with the average net gain of 0 dB, 1 dB and 2 dB are designed individually, where the gain ripple is less than 0.64 dB. The combination of SFLA and TVOS enhance the optimization efficiency and improve the performance of RFA with good gain profile.  相似文献   
22.
湖南省郴州市饭垄堆北段锡钨多金属矿位于湘南钨锡钼铋多金属成矿带东坡矿田内,成矿地质条件优越,具有很好的找矿前景。根据该矿床地质特征以及已有的地质矿产勘查成果,系统总结了矿区101、102、103号主矿体特征。在此基础上,进一步讨论了该类裂隙充填细脉带型锡钨多金属矿床在勘查过程中探矿工程布置的优化方法:即:①探矿工程不宜按每个矿带单独控制,应对整个赋矿层位进行整体控制;②应对含有毒砂、锡、钨细脉的岩性段进行连续取样化验,既可避免漏矿,又可以为将来工业指标调整后重新圈定矿体提供直接依据。  相似文献   
23.
万冬 《石化技术》2020,(4):31-31,54
在埋地管道研究工作中,关于其腐蚀的防护一直是研究的焦点问题,但现阶段常用的防护手段多为防腐层与阴极防护。为此,在文中主要对二者的保护措施展开了相应地阐述,并重点分析了2种保护手段存在的问题,旨在为后续的管道防腐研究提供相应的参考。  相似文献   
24.
This paper presents a control design for the one‐phase Stefan problem under actuator delay via a backstepping method. The Stefan problem represents a liquid‐solid phase change phenomenon which describes the time evolution of a material's temperature profile and the interface position. The actuator delay is modeled by a first‐order hyperbolic partial differential equation (PDE), resulting in a cascaded transport‐diffusion PDE system defined on a time‐varying spatial domain described by an ordinary differential equation (ODE). Two nonlinear backstepping transformations are utilized for the control design. The setpoint restriction is given to guarantee a physical constraint on the proposed controller for the melting process. This constraint ensures the exponential convergence of the moving interface to a setpoint and the exponential stability of the temperature equilibrium profile and the delayed controller in the norm. Furthermore, robustness analysis with respect to the delay mismatch between the plant and the controller is studied, which provides analogous results to the exact compensation by restricting the control gain.  相似文献   
25.
针对多目标绿色可重入混合流水车间调度问题(RHFSP)的特点,在机器分配和工序排序的基础上引入分时电价机制,构建了以最小化最大完工时间、总能耗成本和碳排放为目标的绿色调度优化模型,提出了一种改进的多目标文化基因算法(MOMA)来求解该问题,通过数值实验验证了所设计的MOMA算法的可行性。实验结果表明MOMA算法在非劣解的收敛性、多样性和支配性指标方面都显著优于多目标蚁狮优化算法(MOALO)、多目标粒子群优化算法(MOPSO)和带精英策略的非支配排序遗传算法(NSGA-Ⅱ),四种算法的分布性指标无显著差异。所提出的模型能够使企业有效避开高电价时段作业,合理转移用电负荷,达到降低总用电成本和碳排放的目的。  相似文献   
26.
The minimum cost flow problem (MCFP) is the most generic variation of the network flow problem which aims to transfer a commodity throughout the network to satisfy demands. The problem size (in terms of the number of nodes and arcs) and the shape of the cost function are the most critical factors when considering MCFPs. Existing mathematical programming techniques often assume the cost functions to be linear or convex. Unfortunately, the linearity and convexity assumptions are too restrictive for modelling many real-world scenarios. In addition, many real-world MCFPs are large-scale, with networks having a large number of nodes and arcs. In this paper, we propose a probabilistic tree-based genetic algorithm (PTbGA) for solving large-scale minimum cost integer flow problems with nonlinear non-convex cost functions. We first compare this probabilistic tree-based representation scheme with the priority-based representation scheme, which is the most commonly-used representation for solving MCFPs. We then compare the performance of PTbGA with that of the priority-based genetic algorithm (PrGA), and two state-of-the-art mathematical solvers on a set of MCFP instances. Our experimental results demonstrate the superiority and efficiency of PTbGA in dealing with large-sized MCFPs, as compared to the PrGA method and the mathematical solvers.  相似文献   
27.
BIM技术以三维设计为基础,以数字信息为载体,将建筑信息贯穿于建筑的全生命周期中。然而由于地下工程的内部结构较为复杂,受地质条件影响较大,BIM技术在地下工程中的应用并不多见。叙述了BIM技术在隧道、地铁和矿井建设几种地下工程中应用的现状,并对几个典型案例进行分析,指出了BIM技术在地上工程和地下工程中应用的异同。最后,提出了目前BIM技术在地下工程中应用的问题以及对未来发展的建议。为推动BIM在我国地下工程中更广泛深入的应用提供重要参考价值。  相似文献   
28.
栖霞—大柳行地区位于胶东中部栖霞—蓬莱金矿成矿带内,是胶东重要的金成矿区,成矿条件优越。为了对圈定靶区进行优选分类,通过对该区地质背景、找矿靶区评价、找矿靶区优选方面展开综合研究,并结合勘查工作程度和矿业权设置情况,划分出3类预测区,选定了5个靶区为今后优先部署勘查工作的方向。  相似文献   
29.
我国煤矿生产事故频发,顶板垮落、瓦斯爆炸、机电事故、突水、矿井火灾、放炮等隐患时刻影响着煤矿安全生产,当前矿井开采以井下开采为主,井下开采存在技术要求高、开采难度大的问题,导致煤矿事故发生数和死亡人数相对其他行业居于首位。因此,为了深入研究煤矿事故发生原因和规律,统计了近10 a我国煤矿事故数据,找出当前矿山开采存在的各种安全问题,针对存在的问题提出解决措施,对预防及应对煤矿安全问题具有重要意义。  相似文献   
30.
To deal with uncertainty of the spectral distribution, we consider minimax interpolation and extrapolation problems in Lp for stationary processes. The interpolation and extrapolation problems can be regarded as a linear approximation problem on the unit disk in the complex plane. Although the robust one-step-ahead predictor and interpolator has already been considered separately in the previous literature, we give two conditions for the uncertainty class to find the minimax interpolator and extrapolator in the general framework from both the point of view of the observation set and the point of view of evaluation on the interpolation and extrapolation error under the Lp-norm. We show that there exists a minimax interpolator and extrapolator for the class of spectral densities ε-contaminated by unknown spectral densities under our conditions. When the uncertainty class contains spectral distribution functions which are not absolutely continuous to the Lebesgue measure, we show that there exists an approximate interpolator and extrapolator in Lp such that its maximal interpolation and extrapolation error is arbitrarily close to the minimax error when the spectral distributions have densities. Our results are applicable to the stationary harmonizable stable processes.  相似文献   
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