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1.
Predicting consumption behavior is very important for adjusting supplier production plans and enterprise marketing activities. Conventional statistical methods are unable to accurately predict green consumption behavior because it is characterized by multivariate nonlinear interactions. The paper proposes an optimized fruit fly algorithm (FOA) and extreme learning machine (ELM) model for consumption behavior prediction. First, to address the problem of uneven search direction of FOA leading to insufficient search ability and low efficiency, the paper proposes a sector search mechanism instead of a random search mechanism to improve the global search ability and convergence speed of FOA. Second, to address the issue that the initial weights and hidden layer bias values of the ELM are randomly generated, which affects the learning efficiency and generalization of the ELM, the paper uses an improved FOA to optimize the weights and bias values of ELM for improving the prediction accuracy. Taking the green vegetable consumption behavior of Beijing residents as an example, the results show the optimization of the initial weight and threshold of ELM by the GA, PSO, FOA, and SFOA, the prediction accuracy of the GA-ELM, PSO-ELM, FOA-ELM, and SFOA-ELM models all surpass those of ELM. Compared with BPNN, GRNN, ELM, GA-ELM, PSO-ELM, and FOA-ELM models, the RMSE value of SFOA-ELM was decreased by 9.45%, 8.40%, 11.89%, 5.84%, 2.22%, and 2.69%, respectively. These findings demonstrate the effectiveness of the SFOA-ELM model in green consumption behavior prediction and provide new ideas for the accurate prediction of consumption behaviors of other green products with similar characteristics.  相似文献   
2.
[目的]探析开都河流域在未利用地开发过程中生态风险指数的变化特征,为西北干旱区内陆河流域土地利用结构调整与生态保护修复协调发展提供建议。[方法]文章采用PSR模型构建基于14个指标框架的流域未利用地开发生态风险评价指标体系;通过测度综合生态风险指数法进行时空视角的特征变化与格局划分评价;并运用灰色预测模型前瞻性模糊预测该区域未来4年的生态风险变化态势。[结果]2009—2016年开都河流域未利用地开发生态风险整体呈波动上升趋势,生态风险程度由较低下降至低生态风险水平,随后上升至一般程度。这是因为土地开发利用对生态环境造成压力,但在政府相应生态保护政策的出台落实下又逐步缓解,生态系统结构和功能好转明显,抵御风险能力得以提升。预测结果显示2017—2020年开都河流域生态风险将由一般生态风险程度上升至较高程度,因此需要采取适当的管理措施来消减生态风险发生的可能性。[结论]开都河流域作为沙漠中典型的绿洲生态系统,生态环境较为脆弱,通过未利用地的差别化开发、鼓励零星分散的开发模式以及细分不同地类开发的生态补偿设置等方式路径,以期缓解降低干旱区内陆河流域未利用地开发带来的生态风险。  相似文献   
3.
Are the forecast errors of election-eve polls themselves forecastable? We present evidence from the 2008 Democratic Party nomination race between Barack Obama and Hillary Clinton showing that the answer is yes. Both cross-sectional and time series evidence suggests that market prices contain information about election outcomes that polls taken shortly before the contests do not. Conversely, election surprises relative to polls too Granger cause subsequent price movements. We then investigate whether the additional information in prices could come from the media coverage of these campaigns, and uncover a set of complex relationships between pollster’s surprise, price movements, and various aspects of media coverage. Prices anticipate the balance and content of media coverage, but not the volume. On the other hand, it is the volume of media coverage, not the balance or content, that anticipates the surprise element in election outcomes. Moreover, Granger causality between prices and election surprises barely changes after controlling for media coverage, and causality from media volume to surprises persists too after controlling for price movements. Taken together, the results suggest that both prices and the volume of media coverage contain independent election-relevant information that is not captured in polls.  相似文献   
4.
We study the behaviours of the Betfair betting market and the sterling/dollar exchange rate (futures price) during 24 June 2016, the night of the EU referendum. We investigate how the two markets responded to the announcement of the voting results by employing a Bayesian updating methodology to update prior opinion about the likelihood of the final outcome of the vote. We then relate the voting model to the real-time evolution of the market-determined prices as the results were announced. We find that, although both markets appear to be inefficient in absorbing the new information contained in the vote outcomes, the betting market seems less inefficient than the FX market. The different rates of convergence to the fundamental value between the two markets lead to highly profitable arbitrage opportunities.  相似文献   
5.
21 世纪是海洋的世纪, 海洋强国作为国家重要发展战略, 海洋经济也成为学术研究热点。 把握海洋经济发展态势, 预测海洋经济发展趋势对于科学管理海洋经济发展具有重要意义, 同时也是海洋经济研究的热点问题。 本文基于可视化的角度利用SATI、 Netdraw、 Ucinet 等软件绘制灰色系统理论以及海洋经济灰色研究的知识图谱,基于图谱比较,阐述灰色系统理论的成熟性以及拓宽海洋经济研究方向的重要性,并分析灰色系统理论应用于海洋经济研究的适用性, 进而拓宽海洋经济研究新方法, 更好地把握海洋产业关联度以及预测海洋经济发展趋势, 科学指导海洋经济发展。  相似文献   
6.
基于利益相关者理论,通过文献研究与实地调研,梳理了影响国家级新区绿色增长能力建设的主要因素,并应用Grey DEMATEL方法进行影响因素因果关系分析,在此基础上进一步剖析国家级新区绿色增长能力建设内在机理。研究结果表明:法律法规完善性是影响国家级新区绿色增长能力建设的根本性动力因素,同时,也是新区绿色增长能力建设内在机理的重要外在驱动力。此外,当地居民环境意识也是影响国家级新区绿色增长能力建设的重要结果性因素,而企业绿色管理实践、绿色技术进步与创新能力作为重要的关键性因素,对国家级新区绿色增长能力作用显著,是国家级新区绿色增长能力建设的重要内在驱动力。  相似文献   
7.
[目的]探讨“生态环境—经济发展—城镇化”三维系统(以下简称“EEU”系统)协调发展关系,以期为推动三者全面协调发展提供参考。[方法]文章以西北5省区为例,在构建EEU系统评价指标体系的基础上,运用熵权法、耦合协调模型、GIS工具和灰色预测模型对西北各省区EEU系统耦合协调发展进行分析。[结果]2003—2017年西北5省区EEU系统评价值呈上升趋势,经济发展和城镇化系统评价值呈波动上升态势,明显高于生态环境系统评价值; 耦合度水平较高,协调度整体由过度发展大类向协调发展大类演变; 各省区协调度上升等级不同且未能达到优质协调等级,协调发展的制约因素有经济发展滞后型和生态环境滞后型两大类; 未来5年各省区协调度将稳步提升,但演进差异明显。[结论]提出要遵循科学方法,补齐生态环境短板;突破薄弱环节,推进系统协调发展;重点关注甘肃,实现区域协同发展的对策建议。  相似文献   
8.
借鉴改进的DSIR模型思想,从政府-企业-个人3个层次出发,将制度环境作为一个外生子系统,引入创新驱动战略评价系统,形成制度环境-驱动力-状态-影响-响应5个立体层面的子系统,同时,采用混合型中心点三角白化权函数进行灰色评估分析,对中西部地区6个省市创新驱动发展状况进行实证研究。分析结果表明,在创新驱动发展方面,四川处于同类地区“领跑”地位,河南、湖北、湖南处于“并跑”地位,而陕西和重庆处于落后地位,针对各地区发展短板提出对策建议。  相似文献   
9.
Many regions on earth face daily limitations in the quantity and quality of the water resources available. As a result, it is necessary to implement reliable methodologies for water consumption forecasting that will enable the better management and planning of water resources. This research analyses, for the first time, a large database containing data from 2 million water meters in 274 unique postal codes, in one of the most densely populated areas of Europe, which faces issues of droughts and overconsumption in the hot summer months. Using the R programming language, we built and tested three alternative forecasting methodologies, employing univariate forecasting techniques including a machine-learning algorithm, with very promising results.  相似文献   
10.
We investigate market selection and bet pricing in a repeated prediction market model. We derive the conditions for long-run survival of more than one agent (the crowd) and quantify the information content of prevailing prices in the case of fractional Kelly traders with heterogeneous beliefs. It turns out that, apart some non-generic situations, prices do not converge, neither almost surely nor on average, to true probabilities, nor are they always nearer to the truth than the beliefs of all surviving agents. This implies that, in general, prediction market prices are not maximum likelihood estimators of the true probabilities. However, when more than one agent survives, the average price emerging from a prediction market approximates the true probability with lower information loss than any individual belief.  相似文献   
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