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排序方式: 共有1354条查询结果,搜索用时 15 毫秒
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.
Models of cities based on conventional spatial market theory are unable to replicate a realistic size distribution. The stochastic process approach to size distribution, which assumes proportionate growth, does not provide an economic foundation for spatial trades. There is an apparent irreconcilability. We propose that since there is a continuum of equilibria in models of spatial markets with endogenous location, proportionate growth can work as equilibrium selection. We present computations for an urban configuration that has not been presented in the literature before. A small city locates inside a larger city's agricultural supply zone. This generates a larger variation in city size that may include a realistic size distribution.  相似文献   
3.
We examine differences in information content between order submission sizes and trade sizes by U.S. equity traders. Increasing (decreasing) order submission (trade) size is reflective of information. The result suggests that better-informed traders want to trade in a large size, but that they engage in stealth trading practices or break larger orders into smaller sizes in order to conceal information. While prior studies tend to narrowly focus on trade executions at the market-centre level, our findings indicate that order submission size varies significantly from trade size and that both sizes are informative about future prices, albeit in an inverse manner.  相似文献   
4.
Using China as the research setting, this paper investigates the relationship between economic policy uncertainty and corporate precautionary cash holdings. Empirical results show a U-shaped relation between economic policy uncertainty and corporate precautionary cash holdings. Empirical analysis, in terms of ownership structure, firm size, corporate competitiveness and geographical location, further shows that (i) the effects for economic policy uncertainty in both state-owned and non-state-owned enterprises are significant, but the effect is stronger for state-owned enterprises; (ii) such significant effect is also found more strongly in small and medium-sized enterprises and highly competitive enterprises; and (iii) the effects for eastern, central and western China are all statistically significant, but the effect is strongest for eastern China.  相似文献   
5.
This study examines whether signing auditors from rice planting regions affect audit quality. Using a sample of 12,223 firm-year observations from the Chinese stock market over the period of 2004–2015, our findings reveal that signing auditors from rice regions are significantly negatively associated with the likelihood of unclean audit opinions, suggesting that signing auditors with rice culture are more likely to succumb to the managers and hamper independence, and thus are more inclined to issue favorable audit opinions, and eventually impair audit quality. Furthermore, audit firm size and industry expertise attenuate the negative relation between signing auditors with rice culture and audit quality. In addition, above findings are robust to a variety of sensitivity tests using different measures of audit quality and signing auditors from rice cultivating areas and our conclusions still stand after using the Heckman two-step approach, placebo test and differences-in-differences method to address the potential endogeneity problem.  相似文献   
6.
This paper examines how the level of democracy in a country affects the relationship between fiscal decentralization and government size. We argue that political regimes, proxied by their democracy levels, are important for different decentralization theories to predict the impact of fiscal decentralization on government size. We test this argument using panel data from 76 developed and developing countries during 1972–2013. We find strong and robust evidence that fiscal decentralization is negatively associated with government size and that a higher level of democracy tends to mitigate the negative impact of fiscal decentralization. Therefore, our study contributes to the literature by offering a novel insight on mixed results regarding the relationship between fiscal decentralization and government size in the literature.  相似文献   
7.
陈媛  王伟华  王福颖 《科技和产业》2023,23(16):154-159
选取2021年度数据,采用数据包络分析(DEA)方法对中国东部地区10个省份规模以上工业企业的研发投入绩效进行评价,并采用灰关联分析方法分析确定各项研发投入产出指标相对于DEA效率的灰色关联度。研究结果表明,80%的省份规上工业企业研发投入产出处于非DEA有效状态,存在不同程度的投入冗余或产出不足;规上工业企业发明专利申请数与研发投入产出效率的关联度最高,其次是新产品销售收入和R&D经费内部支出。  相似文献   
8.
BEYOND THE STARS     
It is frequent to hear in economic seminars or read in academic papers that an effect is economically significant or economically important. Yet, the economic literature is vague on what economic importance means and how it should be measured. In this paper, I show that existing measures of economic importance are flawed and misused. I derive a new metric that measures, in percentage terms, the contribution of each explanatory variable to deviations in the dependent variable, ceteris paribus. As an illustration, the method is applied to study the determinants of migration and the determinants of fertility.  相似文献   
9.
Using a rolling cross-sectional sample of over 40,000 U.S. snack food consumers during 2004–2010, we build a three-dimensional model to study how portion sizes, consumption context, and package characteristics jointly affect the amount of food consumed. As with prior research, we find that consumption does increase with larger portions. However, this effect diminishes significantly when accounting for the consumption context and packaging characteristics as consumption drivers. Most important is how the snack is presented to consumers at the point of consumption (type, size, and quantity of packages). We also find that snacking on impulse, alone, with a beverage, or while watching television increases the amount consumed, whereas socializing or snacking at home decrease consumption. We test our model over seven snack types (potato chips, crackers, cheese puffs, nuts and seeds, tortilla chips, pretzels, popcorn), and find that our results hold even for products with different cross-category granularity, palatability, and satiety.  相似文献   
10.
This article aims to improve the predictive ability of KMV model by distinguishing firm size. The evidence suggests that default point would vary with firm size. Using the method of particle swarm optimization, we obtain the optimal default point separately for large firms and small firms. Several statistical tests such as the model confidence set methodology show that our relatively tractable model is more likely to have the strongest predictive ability.  相似文献   
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