Excessive Volatility is Also a Feature of Individual Level Forecasts

The excessive volatility of prices in financial markets is one of the most pressing puzzles in social science. It has led many to question economic theory, which attributes beneficial effects to markets in the allocation of risks and the aggregation of information. In exploring its causes, we investigated to what extent excessive volatility can be observed at the individual level. Economists claim that securities prices are forecasts of future outcomes. Here, we report on a simple experiment in which participants were rewarded to make the most accurate possible forecast of a canonical financial time series. We discovered excessive volatility in individual-level forecasts, paralleling the finding at the market level. Assuming that participants updated their beliefs based on reinforcement learning, we show that excess volatility emerged because of a combination of three factors. First, we found that submitted forecasts were noisy perturbations of participants’ revealed beliefs. Second, beliefs were updated using a prediction error based on submitted forecast rather than revealed past beliefs. Third, in updating beliefs, participants maladaptively decreased learning speed with prediction risk. Our results reveal formerly undocumented features in individual-level forecasting that may be critical to understand the inherent instability of financial markets and inform regulatory policy.     

河南省耕地与粮食变化分析及预测

河南省是我国重要的粮食生产基地,其稳定的耕地资源对粮食生产具有重要意义.本文利用河南省29年耕地资源和粮食产量数据进行分析,研究了粮食生产和耕地资源的变化特征.结果表明,随着河南省人口的不断增长,耕地资源在不断减少,其人均耕地面积也在不断下降;河南省粮食总产量和单产极不稳定,给社会经济发展和粮食安全带来了隐患.最后,建立GM(1,1)预测模型,对2010年、2015年和2020年粮食产量、人均耕地等分别进行了预测.针对预测结果,提出了稳定、提高耕地资源和粮食生产的具体建议与对策,为政府正确决策提供了科学依据.     

水价对中国北方城市居民用水需求影响分析

介绍城市居民用水需求变化的背景,对北方城市居民用水需求进行了预测。得出结论：水价对于减少城市居民用水需求的作用非常显著;城市化的高速发展会对城市居民用水造成巨大压力,对城市居民用水价格、用水管理手段和农业节水制度的积极改革,为解决城市居民用水供需缺口提供可能。     

黑龙江森工林区林业产业结构演变趋势及优势产业选择

采用灰色预测方法对黑龙江森工林区2018—2027年林业三次产业产值进行预测,并在此基础上利用动态偏离-份额分析方法对此阶段黑龙江森工林区的林业优势产业进行选择。结果表明:2019年黑龙江森工林区林业产业结构将演变为"三、一、二"模式;林业第一产业中的林木育种和育苗、经济林产品的种植和采集业可作为优势产业进行重点发展和管理。因此,提出优化黑龙江森工林区林业产业结构的相关建议:继续巩固发展林木育种和育苗、经济林产品的种植和采集这两个优势产业;推动加工制造业向深加工、精加工的方向转变;加强林业旅游与休闲服务业的竞争力。     

Forecasting of electricity costs based on an enhanced gray-based learning model: A case study of renewable energy in Taiwan

This work presents a novel gray-based cost efficiency (GCE) model that integrates the gray forecasting model into a two-factor cost efficiency curve model for renewable energy (RE) technologies and identifies the optimal forecasting model for power generation cost of RE technologies. The analytical framework of proposed GCE model improves short-term prediction of power generation cost, and can be applied during the early developmental stages for RE technologies. Empirical analysis is based on wind power data for Taiwan. Time lag of knowledge stock was simulated to represent the actual relationship between R&D expenditures and cost reductions in power generation by knowledge stock. Analytical results demonstrate the GCE model is a useful tool to quantify the influences of cost reductions in power generation. The implications of analytical results are that institutional policy instruments play an important role in RE technologies achieving cost reductions and market adoption. The proposed GCE model can be applied to all high-technology cases, and particularly to RE technologies. The study concludes by outlining the limitations of the proposed GCE model and directions for further research.     

建立河北省农业生态安全预警机制的理论探讨

目前,河北省农业生态系统整体呈不断恶化趋势,已成为影响建立农业强省的重要问题。为此,建立生态安全预警机制是必要而紧迫的。本文依据农业生态学原理、环境库兹涅兹曲线与生态安全耦合原理建立了农业生态安全的理论基础,并从观念、技术、政府作用与公众参与以及生态产权和资金投入方面进行了障碍性因素分析,最后提出了相应的对策措施。     

ARIMA计量技术下河南省农民增收的预测模型研究

笔者根据河南省1978年～2005年的农民人均纯收入统计数据,将这些数据进行平稳化、零均值化处理,并利用时间序列的自相关函数,偏自相关函数的性质,确认数据所适合的模型.通过对样本数据所做的回归拟合模型定量分析,从而为河南省"十一·五"规划提供量化指标依据.     

战时装备维修备件品种确定步骤与方法研究

着眼于战时特点,阐述准确确定战时装备维修备件需求的重要性,对我军在确定战时装备维修备件需求方面存在的不足进行了分析。针对现代战争“精确化”保障的特殊要求,结合我军现有的理论成果和实践经验,探讨系统科学地确定战时装备维修备件品种的程序和方法。     

基于CatBoost的护士离职预测研究

针对传统的离职预测算法应用于现实中高维度小样本不平衡数据集时存在准确度低、易过拟合、鲁棒性差等问题,应用梯度增强集成分类器CatBoost算法,进行类别型特征处理,利用BOHB(Bayesian Optimization and Hyperband)寻找最优参数,结合交叉验证对模型分类性能进行评估,建立分类模型并对护士离职情况进行预测。该算法采用高维小样本不平衡特征的上海部分公立医院的护士离职数据集,并与XGBoost、随机森林、支持向量机进行对比。实验结果表明,该算法准确度高,鲁棒性强,能够有效地对护士离职进行预测。     

城市水资源承载力与城市规模研究——以玉州—福绵—北流一体化概念规划方案为例

水资源承载能力对于一个国家、地区、城市的综合发展及发展规模至关重要,社会经济发展必须控制在水资源承载能力之内,才能通过以水资源的可持续利用实现社会经济的可持续发展。在玉州-福绵-北流一体化概念规划中,通过引入水资源承载力、生态需水量等概念,重点探讨研究了以水资源约束为特征的资源环境承载力,并以之为前提确定合理的城市规模。