Modified efficient importance sampling for partially non‐Gaussian state space models

The construction of an importance density for partially non‐Gaussian state space models is crucial when simulation methods are used for likelihood evaluation, signal extraction, and forecasting. The method of efficient importance sampling is successful in this respect, but we show that it can be implemented in a computationally more efficient manner using standard Kalman filter and smoothing methods. Efficient importance sampling is generally applicable for a wide range of models, but it is typically a custom‐built procedure. For the class of partially non‐Gaussian state space models, we present a general method for efficient importance sampling. Our novel method makes the efficient importance sampling methodology more accessible because it does not require the computation of a (possibly) complicated density kernel that needs to be tracked for each time period. The new method is illustrated for a stochastic volatility model with a Student's t distribution.     

机构投资者与个人投资者非理性行为差异研究

机构投资者与个人投资者是证券市场的重要组成部分,其非理性程度直接影响着市场的健康稳定。本文基于有情境元素的问卷调查,构建包含投资者类别为自变量,年龄和性别为控制变量,16种常见非理性行为为因变量的分析框架,实证检验机构投资者与个人投资者非理性行为差异。结果表明,中国机构投资者与个人投资者都存在严重的非理性行为;相比机构投资者,个人投资者非理性程度更为严重;机构投资者与个人投资者在偏好逆转、证实性偏差、沉没成本、模糊厌恶、处置效应和损失厌恶方面存在显著差异。本研究为投资者防范非理性行为提供建议,为市场稳定发展提供参考。     

白色酿酒葡萄品种制汁适性及稳定性研究

由于加工葡萄汁的品种要求出汁率高,风味独特,糖、酸、香味和涩味成分平衡,故品种选择对制汁质量十分重要。本实验根据不同白色酿酒品种的葡萄汁,分析其主要成分及特征指标,来评定该品种是否适合制汁以及其制成汁的稳定性。     

人工挖孔桩半桩支护方案可行性分析

本文以实际工程深基坑工程为研究对象,分别对桩基进行数值计算和数值模拟,通过对结果进行对比可以看出,人工挖孔桩采用半桩基是可行的。     

对国有企业党组织参与企业重大决策的认识和思考

随着以现代企业制度建设为主要途径的国企改革不断深入,国有企业党建工作的任务、环境、工作对象、党组织和党员自身都发生了深刻变化。本文就党组织参与国有企业重大决策问题展开论述,以进一步强调党组织在企业中的政治核心作用,为提升国企党建科学化水平奠定理论基础。     

矿井通风三维可视化系统及优化

系统建立了三维仿真框架,建立了三维空间属性模型和非空间属性模型,分别对空间数据和非空间数据进行储存和管理。并建立了Hardy-Cross迭代模型和离散反馈型神经网络模型优化通风网络模型。并以C#语言来实现系统的功能。     

Exploring the impact of the physical conditions of mannequin displays on mental simulation: An embodied cognition theory perspective

This study examines how mannequins' physical conditions of display height and distance are related to consumers’ shopping motivations in generating mental simulation resulting in purchase intention. A 2 × 2 x 2 between-subjects lab experiment (n = 249) was conducted to address this question. The results reveal a significant three-way interaction effect of display height, distance, and shopping motivation. Specifically, it is found that for those with a dominant hedonic shopping motivation, a mannequin displayed up high generates greater mental simulation than one displayed down low, but for those with a dominant utilitarian shopping motivation, a mannequin displayed high and close to consumers generates greater mental simulation than one displayed low and close to them. This study also reveals that mental simulation mediates the influence of the interaction effect of “display height x distance,” moderated by shopping motivation, on purchase intention. Important theoretical and practical implications for retail managers are discussed.     

投资者动机对众筹投资决策的影响

基于慈善理论,投资者动机分为内源动机、外源动机和提升声誉动机,这些动机既能影响众筹投资者的投资决策,也会相互影响。本文借助"众筹网"的投资数据,对投资者进行分类,考察投资者动机对众筹决策的影响。研究结果显示外源动机投资者、提升声誉动机投资者的投资金额更高;进一步探究内源动机与声誉动机的相互影响,结果显示二者负相关,内源动机投资者更关注内心满足,而对声誉需求较少。该研究可以辅助筹资者设置项目内容吸引不同动机投资者,并帮助众筹平台优化服务,从而提高项目融资效率和成功率。     

The consumption–investment decision of a prospect theory household: A two-period model

This study extends the literature on portfolio choice under prospect theory preferences by introducing a two-period life cycle model, where the sufficiently loss averse household decides on optimal consumption and investment in a portfolio with one risk-free and one risky asset. The optimal solution depends primarily on whether the household’s present value of the consumption reference levels is below, equal to, or above the present value of its endowment income. Reference levels below the endowment income are associated with the self-enhancement motive. In this case, the household avoids relative losses in consumption in any present or future state of nature (good or bad). As a result the degree of loss aversion does not directly affect optimal consumption and risk taking activity. Reference levels equal to the endowment income are associated with the belonging motive. An example would be a household comparing to others that belong to the same social class. In this case the household’s optimal consumption is the reference consumption and the household will not invest in the risky asset. Finally, reference levels above the endowment income are associated with the self-improvement motive (or high aspirations). For such high reference levels, households cannot avoid experiencing a relative loss in consumption, either now or in the future. As a result, loss aversion directly affects consumption and risky investment.     

A weighted max-min model for fuzzy multi-objective supplier selection in a supply chain

Supplier selection is one of the most important activities of purchasing departments. This importance is increased even more by new strategies in a supply chain. Supplier selection is a multi-criteria decision making problem in which criteria have different relative importance. In practice, for supplier selection problems, many input information are not known precisely. The fuzzy set theories can be employed due to the presence of vagueness and imprecision of information. A weighted max-min fuzzy model is developed to handle effectively the vagueness of input data and different weights of criteria in this problem. Due to this model, the achievement level of objective functions matches the relative importance of the objective functions. In this paper, an analytic hierarchy process (AHP) is used to determine the weights of criteria. The proposed model can help the decision maker (DM) to find out the appropriate order to each supplier, and allows the purchasing manager(s) to manage supply chain performance on cost, quality and service. The model is explained by an illustrative example.