Towards a real-time prediction of waiting times in emergency departments: A comparative analysis of machine learning techniques

Emergency Departments (EDs) can better manage activities and resources and anticipate overcrowding through accurate estimations of waiting times. However, the complex nature of EDs imposes a challenge on waiting time prediction. In this paper, we test various machine learning techniques, using predictive analytics, applied to two large datasets from real EDs. We evaluate the predictive ability of Lasso, Random Forest, Support Vector Regression, Artificial Neural Network, and the Ensemble Method, using different error metrics and computational times. To improve the prediction accuracy, new queue-based variables, that capture the current state of the ED, are defined as additional predictors. The results show that the Ensemble Method is the most effective at predicting waiting times. In terms of both accuracy and computational efficiency, Random Forest is a reasonable trade-off. The results have significant practical implications for EDs and hospitals, suggesting that a real-time performance monitoring system that supports operational decision-making is possible.     

货币时间价值在投资决策中的应用

货币时间价值的客观存在不仅在理论界得到了公认,而且其产生的作用时刻影响着人们的日常经济生活。不管是企业的项目投资,还是个人的理财投资,都不可忽视货币时间价值。在进行方案抉择的时候,要优先选用包含货币时间价值的动态指标(净现值、获利指数和内涵报酬率)进行评价,选择最优方案,做出科学的投资决策。企业和个人要牢固树立货币时间价值观念,利用它为企业和个人决策服务,促进企业和个人合理利用有限资金,创造更高的效益。     

黄河流域城市群综合承载力评价及时空分异演进

选取2008—2018年黄河流域七大城市群的面板数据,通过熵权法、Moran系数、核密度估计建立城市群综合承载力评价指标体系,并从时间和空间的维度对黄河流域城市群的综合承载力状况进行时空分异演进分析。研究结论如下:黄河流域城市群综合承载力呈现显著空间自相关,城市之间承载力发展不均衡,黄河流域城市群综合承载力现出向中高水平的路径依赖发展趋势。研究认为,提升黄河流域城市群的综合承载力应积极探索富有地域特色的发展战略,以中心城市为核心加强城市群内各城市协同发展,创新机制促进高质量发展。     

渐进式还是突变式？城镇居民食品 消费结构转变规律研究

本文在总结国内外文献的基础上,利用一个嵌入时间路径的LA/AIDS模型,探索了城镇居民食品消费结构的转变规律。结果显示,城镇居民主要食品的消费结构发生了渐进式转变,其转变期为1994-1995年。从需求弹性值变化来看,肉类从奢侈品转变为必需品,发生了本质变化,其消费量逐年上升。粮食和禽蛋类一直是必需品,其弹性值变化不大,消费量逐年下降。而水产品仍是富于弹性的奢侈品,但其弹性值逐渐下降,并趋于必需品。     

Prediction of the next hypercalcemia free period: application of random effect models with selection on first event

The length of repeated hypercalcemia free periods of patients with bone metastasis of breast cancer with at least one hypercalcemic event was modelled according to a generalized linear mixed model formulated in terms of transition probabilities and according to a latent variable model. In the former case the periods were assumed to be lognormally distributed with two variance components (patients and residue). In the latter case the conditional intensity given a patient was assumed to be the intensity of the Weibull distribution, while the random patient effect (frailty) was assumed to be drawn from a gamma distribution. In both cases the selection of only patients with at least one hypercalcemic event was taken into consideration. In both models the variance of the patient effect turned out to be negligible. For the second and later periods the Weibull appeared to fit better than the lognormal model. For the first period there was almost no information available.     

保费收入随机化条件下的保险公司破产概率模型研究

保费收入是保险公司破产概率的重要影响因素。传统的保险公司破产概率模型常将保费收入过程看作连续的确定性过程,然而在现实中,保费收入过程却是一个离散的随机过程。本文用复合泊松过程描述保费收入,从而将确定性保费收入条件下的破产概率模型拓展到随机化保费收入条件下的破产概率模型,在此基础上模拟计算了保险公司破产概率,并比较分析了不同的保险资金投资模式对破产概率的影响。     

Product innovation and sustainable marketing: effects on consumer innovativeness

Based on the theory of sustainable marketing and time cognition, this study constructed a theoretical model among product innovation, sustainable marketing, time perspectives, and customer innovativeness. Using a sample of 290 consumers in China respond to a new energy vehicle, this paper examines the influence of firm's product innovation on customer innovativeness through the paths of sustainable marketing and time perspectives. The results showed that product innovation positively affected three dimensions of sustainable marketing, which then had different effects on present and future time perspectives. Time perspectives positively affected consumer innovativeness. According to the findings, this study discussed implications for theory, practice, and future work.     

生产劳动力的劳动时间的探讨

传统经济学的劳动力价值理论只有生产劳动力的生产费用(物化劳动),没有生产劳动力的劳动时间(活劳动)的耗费。劳动力的生产也有劳动时间的耗费。劳动力的自然再生产时间不形成劳动力的价值,劳动力的社会再生产时间、即学习劳动的时间形成劳动力的价值。劳动力价值包括两个部分:一是生产劳动力的物化劳动,如生活费用和学习费用等;二是生产劳动力的活劳动即学习劳动。     

旅游形象认知的时间顺序对旅游目的地形象认知的影响研究--以银川沙湖与榆林红碱淖为例

旅游者对旅游目的地的形象认知是影响旅游活动的重要因素,对旅游目的地形象定位和市场营销策略的选择都具有重要的参考价值。许多因素对旅游目的地形象认知都产生影响,其中认知的时间特征对旅游目的地形象认知的影响是一个值得关注的新课题:旅游者对不同旅游目的地形象认知的先后顺序对旅游目的地形象认知是否产生影响以及这种影响的程度如何。文章以银川沙湖与榆林红碱淖为例,对旅游者对旅游目的地形象认知中的“先入为主”与“既成事实”效应进行了分析,初步证明旅游者对不同旅游目的地形象感知的先后顺序对旅游目的地形象认知产生影响,并针对案例景区的情况,强调了旅游形象定位与市场营销中的先发优势,提出了自己的观点。