洪水预报经验模型的混合蛙跳优化率定

API模型广泛应用于洪水预报和水资源管理等领域,但API模型定线往往采用人工方式进行绘制,在精度和效率上比较欠缺。江苏省洪水预警预报平台在研发过程中为提高API模型预报精度,采用混合蛙跳算法(SFLA)对API模型定线进行优化。分析混合蛙跳算法对API模型进行参数优化和智能定线的方法,并通过混合蛙跳算法、传统方法对71场洪水进行绘制,与传统定线方法相比,证实混合蛙跳法能有效提高API模型预报精度。     

混合蛙跳算法应用研究

混合蛙跳算法（SFLA）是一种模拟青蛙觅食行为的智能优化算法.算法具有设置参数少、简单易于理解、鲁棒性强等特点.由于该算法提出的时间不长,目前对此算法的研究成果并不多,该算法在理论和实践上还不够成熟,如该算法的鲁棒性、收敛性、稳定性等数学理论还未给出完整的数学证明,算法的适用范围目前还仅限于函数优化、组合优化、单目标优化、多目标优化等方面.本文重点分析研究了该算法的基本原理、应用前景、国内外的研究现状和主要研究内容,以及目前该算法研究过程中出现的问题.     

基于API模型的中小水库洪水预报理论研究与系统开发

入库洪水实时预报是中小水库管理单位共同面临的难题,本文运用API（前期雨量指数）产流模型配合谢尔曼单位线进行汇流计算,结合中小水库产汇流特点,合理概化并优选参数,提出了一种适用于中小水库入库洪水实时预报方案,进一步基于国产组态软件实现二次开发,设计了一款适用于中小水库入库洪水预报软件,适配国内主流水情自动测报系统。以重庆某水库2013-2022年实测入库流量为研究对象,结果表明本预报方案具有一定精度,可供无洪水预报系统中小水库管理技术人员参考使用。     

基于改进混合蛙跳算法的微电网优化配置方法研究

微电网内分布式电源波动较大,对并网产生了一些负面影响。将有功网损和静态电压结合建立多目标优化模型,采用改进的混合跳蛙算法求解含约束的多目标优化模型,并为微电网配置更好的运行模式。通过仿真进行对比分析,验证该方法的优越性。结果表明,该方法能较好地协调系统的多目标,虽然各子目标不是最优的,但可以很好地调整各子目标之间的关系,达到整体优化的效果。     

求解复杂函数优化问题的混合蛙跳算法*

针对基本混合蛙跳算法在处理复杂函数优化问题时容易陷入局部最优、收敛速度慢的缺点,提出了一种改进的混合蛙跳算法。该算法把生物学中的吸引排斥思想引入到混合蛙跳算法中,修正了其更新策略,从而维持了子群的多样性。实验仿真结果表明,改进的混合蛙跳算法提高了算法的收敛速度,有效地避免了SFLA的早熟收敛问题,从而改善了对复杂问题的搜索效率,数值实验结果验证了算法的有效性和鲁棒性。     

改进的混合蛙跳算法在传感器配置优化中的应用

传感器配置优化是可测性设计的重要研究内容,将混合蛙跳算法应用于传感器配置优化是一种新的尝试。针对传感器配置优化属于离散问题求解,提出离散的混合蛙跳算法,设计了一种离散化的更新方式。为克服蛙跳算法的早熟收敛问题,在改进的离散蛙跳算法中采用混沌优化算法以概率的形式对全局极值进行了优化。最后通过具体系统实例验证了该方法的正确性和有效性。     

自适应分组混沌云模型蛙跳算法求解连续空间优化问题

针对经典混合蛙跳优化算法寻优精度不高和易陷入局部收敛区域的缺点,结合云模型在定性与定量之间相互转换的优良特性,提出一种自适应分组混沌云模型蛙跳算法.通过反向学习机制初始化种群,应用云模型算法对优秀子群组的收敛区域进行局部搜索更优位置,应用混沌理论在收敛区域以外空间探索全局最优位置.典型复杂函数测试表明,所提出的算法能有效找出全局最优解,适用于多峰值函数寻优.     

求解多目标优化问题的自适应混沌混合蛙跳算法

针对多目标优化问题提出一种自适应混沌混合蛙跳算法MACSFLA(Adaptive chaos shuffled frog leaping algorithm for multiobjective optimization)。使用动态权重因子策略以提高混合蛙跳算法SFLA(Shuffled Frog Leaping Algorithm)收敛效率,引入基于Pareto支配能力的SFLA子族群划分策略,使得SFLA能够应用于多目标优化问题。在此基础上,MACSFLA首先利用SFLA快速寻优能力接近理论Pareto最优解,然后采用自适应网格密度机制动态维护外部存储器Pareto最优解规模,并使用自适应混沌优化技术改善Pareto最优解集样本多样性,最后利用Pareto最优解选择策略为青蛙种群选择最优更新粒子。多目标函数测试实验结果表明,与MOPSO和NSGA-Ⅱ相比,MACSFLA在Pareto最优解集均匀性和多样性上有明显优势。     

基于蚁群–混合蛙跳算法的贴片机贴装顺序优化

针对喂料器的位置确定的条件下,研究拱架式贴片机的元器件贴装顺序优化问题.建立了新的拱架式贴片机贴装顺序的数学模型.针对问题的路径寻优特点,把混合蛙跳算法与蚁群算法相融合,实现对贴片机的元件贴装顺序优化问题的求解.在算法中提出了适应于贴片机实际贴装情况的分段启发函数、分段信息素以及信息素的分段更新策略等多种改进方法.为验证算法有效性,以20块实际生产的PCB为实例进行了测试.实验结果表明,算法具有较好的求解精度和全局搜索能力,与文献中的单一混合蛙跳算法相比,平均效率提高了7.89%;与蚁群算法相比,平均效率提高了3.79%.     

An application of pruning in the design of neural networks for real time flood forecasting

We propose the application of pruning in the design of neural networks for hydrological prediction. The basic idea of pruning algorithms, which have not been used in water resources problems yet, is to start from a network which is larger than necessary, and then remove the parameters that are less influential one at a time, designing a much more parameter-parsimonious model. We compare pruned and complete predictors on two quite different Italian catchments. Remarkably, pruned models may provide better generalization than fully connected ones, thus improving the quality of the forecast. Besides the performance issues, pruning is useful to provide evidence of inputs relevance, removing measuring stations identified as redundant (30–40% in our case studies) from the input set. This is a desirable property in the system exercise since data may not be available in extreme situations such as floods; the smaller the set of measuring stations the model depends on, the lower the probability of system downtimes due to missing data. Furthermore, the Authority in charge of the forecast system may decide for real-time operations just to link the gauges of the pruned predictor, thus saving costs considerably, a critical issue in developing countries.

Parameter optimization of software reliability growth model with S-shaped testing-effort function using improved swarm intelligent optimization

Software reliability growth model (SRGM) with testing-effort function (TEF) is very helpful for software developers and has been widely accepted and applied. However, each SRGM with TEF (SRGMTEF) contains some undetermined parameters. Optimization of these parameters is a necessary task. Generally, these parameters are estimated by the Least Square Estimation (LSE) or the Maximum Likelihood Estimation (MLE). We found that the MLE can be used only when the software failure data to satisfy some assumptions such as to satisfy a certain distribution. However, the software failure data may not satisfy such a distribution. In this paper, we investigate the improvement and application of a swarm intelligent optimization algorithm, namely quantum particle swarm optimization (QPSO) algorithm, to optimize these parameters of SRGMTEF. The performance of the proposed SRGMTEF model with optimized parameters is also compared with other existing models. The experiment results show that the proposed parameter optimization approach using QPSO is very effective and flexible, and the better software reliability growth performance can be obtained based on SRGMTEF on the different software failure datasets.     

An empirical study of intelligent expert systems on forecasting of fashion color trend

Forecasting future color trend is a crucially important and challenging task in the fashion industry including design, production and sales. In particular, the trend of fashion color is highly volatile. Without advanced methods, it is very hard to make fashion color trend forecasting with reasonably high accuracy, and it is a handicap for development of the intelligent expert systems in fashion industry. As a result, many prior works have employed traditional regression models like ARIMA or intelligent models such as artificial neural network (ANN) and grey model (GM) for conducting color trend forecasting. However, the reported accuracies of these forecasting methods vary a lot, and there are controversies in the literature on these models’ performances. As a result, in this paper, we systematically compare the performances of ARIMA, ANN and GM models and their extended family methods. With real data analysis, our results show that the ANN family models, especially for Extreme Learning Machine (ELM) with Grey Relational Analysis (GRA), outperform the other models for forecasting fashion color trend.     

A novel axle temperature forecasting method based on decomposition,reinforcement learning optimization and neural network

Axle temperature forecasting technology is important for monitoring the status of the train bogie and preventing the hot axle and other dangerous accidents. In order to achieve high-precision forecasting of axle temperature, a hybrid axle temperature time series forecasting model based on decomposition preprocessing method, parameter optimization method, and the Back Propagation (BP) neural network is proposed in this study. The modeling process consists of three phases. In stage I, the empirical wavelet transform (EWT) method is used to preprocess the original axle temperature series by decomposing them into several subseries. In stage II, the Q-learning algorithm is used to optimize the initial weights and thresholds of the BP neural network. In stage III, the Q-BPNN network is used to build the forecasting model and complete predicting all subseries. And the final forecasting results are generated by combining all prediction results of subseries. By comparing all results over three case predictions, it can be concluded that: (a) the proposed Q-learning based parameter optimization method is effective in improving the accuracy of the BP neural network and works better than the traditional population-based optimization methods; (b) the proposed hybrid axle temperature forecasting model can get accurate prediction results in all cases and provides the best accuracy among eight general models.     

基于微粒群算法和网格模型的参数优化方法

针对在半导体制造工艺参数优化过程中缺乏直观参考的问题,在微粒群优化算法(PSO)和等值线理论分析的基础上,将PSO与等值线矩形网格模型相结合,提出一种全新的工艺参数窗口选择方法,在二维标准多峰函数上验证了所提出方法的有效性,同时对所提出的方法进行了实际生产验证,对于双输入参数问题,该方法可以直接输出所有满足工艺要求的二维区域,从而为参数优化和范围选取提供直观参考,仿真测试结果和生产验证数据均表明了所提出的算法是一种有效的参数优化方法。     

PeRSIVA: An empirical evaluation method of a student model of an intelligent e-learning environment for computer programming

In this paper an evaluation method for assessing the effectiveness, accuracy and validity of a student model was presented. Our method is called PeRSIVA and is a combination of the well-known evaluation method of Kirkpatrick and the layered evaluation framework. These well-known and commonly used evaluation techniques have been selected in order to design an accurate and correct evaluation methodology, since there are no clear guidelines in the literature for the evaluation of the student model of an adaptive tutoring system. Furthermore, PeRSIVA method was used to evaluate the hybrid student model, which combines an overlay model with stereotypes and fuzzy logic techniques, of an e-learning system. Particularly, PeRSIVA assesses the results of student modeling in students' satisfaction, performance, progress, behavior and state, as well as the validity of the conclusions drawn by the student model and the validity of the adaptation decision making. The e-learning system was used by the students of a postgraduate program in the field of informatics in the University of Piraeus and the evaluation results demonstrated learning improvements in students and adaptation success to students' needs.     

An intelligent information sharing strategy within a swarm for unconstrained and constrained optimization problems

 In this paper we present a new multilevel information sharing strategy within a swarm to handle single objective, constrained and unconstrained optimization problems. A swarm is a collection of individuals having a common goal to reach the best value (minimum or maximum) of a function. Among the individuals in a swarm, there are some better performers (leaders) those that set the direction of search for the rest of the individuals. An individual that is not in the better performer list (BPL) improves its performance by deriving information from its closest neighbor in BPL. In an unconstrained problem, the objective values are the performance measures used to generate the BPL while a multilevel Pareto ranking scheme is implemented to generate the BPL for constrained problems. The information sharing strategy also ensures that all the individuals in the swarm are unique as in a real swarm, where at a given time instant two individuals cannot share the same location. The uniqueness among the individuals result in a set of near optimal individuals at the final stage that is useful for sensitivity analysis. The benefits of the information sharing strategy within a swarm are illustrated by solving two unconstrained problems with multiple equal and unequal optimum, a constrained optimization problem dealing with a test function and a well studied welded beam design problem.     

A hybrid approach for portfolio construction: Combing two-stage ensemble forecasting model with portfolio optimization

Combining the stock prediction with portfolio optimization can improve the performance of the portfolio construction. In this article, we propose a novel portfolio construction approach by utilizing a two-stage ensemble model to forecast stock prices and combining the forecasting results with the portfolio optimization. To be specific, there are two phases in the approach: stock prediction and portfolio optimization. The stock prediction has two stages. In the first stage, three neural networks, that is, multilayer perceptron (MLP), gated recurrent unit (GRU), and long short-term memory (LSTM) are used to integrate the forecasting results of four individual models, that is, LSTM, GRU, deep multilayer perceptron (DMLP), and random forest (RF). In the second stage, the time-varying weight ordinary least square model (OLS) is utilized to combine the first-stage forecasting results to obtain the ultimate forecasting results, and then the stocks having a better potential return on investment are chosen. In the portfolio optimization, a diversified mean-variance with forecasting model named DMVF is proposed, in which an average predictive error term is considered to obtain excess returns, and a 2-norm cost function is introduced to diversify the portfolio. Using the historical data from the Shanghai stock exchange as the study sample, the results of the experiments indicate the DMVF model with two-stage ensemble prediction outperforms benchmarks in terms of return and return-risk characteristics.     

An evolutionary method for complex-process optimization

In this paper we present a new evolutionary method for complex-process optimization. It is partially based on the principles of the scatter search methodology, but it makes use of innovative strategies to be more effective in the context of complex-process optimization using a small number of tuning parameters. In particular, we introduce a new combination method based on path relinking, which considers a broader area around the population members than previous combination methods. We also use a population-update method which improves the balance between intensification and diversification. New strategies to intensify the search and to escape from suboptimal solutions are also presented. The application of the proposed evolutionary algorithm to different sets of both state-of-the-art continuous global optimization and complex-process optimization problems reveals that it is robust and efficient for the type of problems intended to solve, outperforming the results obtained with other methods found in the literature.     

基于经验模态分解的混合软件可靠性预测模型

基于经验模态分解结合支持向量回归算法与灰色系统理论提出一种混合软件可靠性预测模型,通过对原始软件失效数据使用经验模态分解方法进行预处理,将失效数据分解得到不同频段的本征模态分量和剩余分量,用支持向量回归算法对本征模态分量进行预测,用灰色系统模型GM（1,1）对剩余分量进行预测,然后将预测结果进行重构,得到最终软件可靠性预测值。为了验证所提混合预测模型的有效性,利用两组真实软件失效数据,与SVR可靠性预测模型和GM（1,1）可靠性预测模型进行实验对比分析,实验结果表明,所提混合预测模型较这两种可靠性预测模型具有更精确的预测精度。