A fuzzy comprehensive evaluation algorithm for analyzing electronic word-of-mouth

This study evaluates tourism experiences shared through electronic word-of-mouth (eWOM) across four Chinese attractions. The objective is to develop a framework for evaluating eWOM by constructing an indicator system and implementing an analytic hierarchy process with the use of a fuzzy comprehensive evaluation algorithm. This framework is achieved by mapping more than 6000 websites related to Chinese tourism attractions and filtering over 200,000 useful reviews to measure service performance. Results indicate that ecological–biological attractions failed to make tourists feel “very satisfied” in various aspects, such as overall evaluation, infrastructure, traffic, natural environment, and social environment. Overall, the study contributes by presenting a framework that can be adopted by tourism researchers and industry practitioners to understand tourist preferences and evaluate service performance to improve service quality.     

基于IK-MD-SA聚类算法的电力数据审计疑点研究

为解决电力行业海量非结构化数据导致审计疑点数据效率、准确性低的难题,本文提出了一种基于迭代IK-MD-SA聚类电力大数据审计疑点算法。首先运用相异性度量算法通过构造相异性矩阵和计算均值相异性改进K-means聚类算法选择初始聚类中心,并将簇均值替换为簇中位数完成后续聚类中心迭代,以消离群点影响聚类结果的准确性。然后利用改进的蜂群算法对聚类结果进行优化,使其保证高运行效率的前提下聚类结果仍具有较高准确性。最后,通过离散性电力数据进行识别潜在疑点试验,验证了所提算法的可行性和有效性。     

CEV模型下两值期权的数值解

假设标的股价服从不变方差弹性（CEV）模型下，推导出两值期权的定价公式。利用有限差分格式，给出具体的数值算法，并将其应用于实例中，通过对此算例做的一系列数值实验，验证了算法的有效性。     

一种动态加权的LDPC译码方法

为了加快低密度奇偶校验（LDPC）码的译码速度,有效改善LDPC码的译码性能,针对校验节点更新过程中的对数似然比（LLR）值的大小,设计了一种LDPC码的动态加权译码方法。以IEEE 802.16e标准的奇偶校验矩阵为例,根据LLR值的变化规律,利用增长因子和抑制因子对和积译码算法和最小和译码算法进行动态加权。仿真结果显示,基于动态加权的译码方法相对于传统译码方法误码率都有明显改进,译码复杂度也有所降低。     

基于遗传算法的供应链分销网络模型及其求解

本文研究了由多个厂商、多个分销中心和零售商组成的供应链分销网络,建立了综合考虑库存成本、订货成本和运输成本的分销网络优化模型。该模型是一个整数规划问题,采用遗传算法,并建立一个有效的编码方式来进行快速求解。最后通过一个实例验证了该模型的有效性和实用性。     

基于YOLOv3的H型钢表面缺陷检测系统

为了提升H型钢的表面质量和安全系数,设计了一种基于YOLOv3算法的型钢表面缺陷检测系统.设计的检测系统由硬件系统和软件系统组成:硬件系统包括八角架式图像采集装置、电动控制系统和通信系统;软件系统采用YOLOv3目标检测算法.现场测试结果表明:1)检测系统可实时采集图像,并根据H型钢的规格型号能够自动调节图像采集装置结...     

A network approach to modeling the multi-echelon spare-part inventory system with backorders and interval-valued demand

A multi-echelon inventory system implies the existence of a hierarchy of stocking locations, and the dependence and interaction between them. We consider a multi-echelon, spare-part inventory management problem with outsourcing and backordering. The problem is characterized by deterministic repair time/cost, and supply and demand that lie within prescribed intervals and that vary over time. The objective is to minimize the total inventory and transportation costs. We develop a network model for problem analysis and present a network flow algorithm for solving the problem. We prove that the Wagner-Whitin property, known for the lot-sizing problem, can be extended to the spare-part inventory management problem under study.     

基于两层架构协调的应急物资分配与车辆调度集成优化方法

针对突发事件下的应急物资调运问题，考虑了多个地区同时受灾以及多个出救点需要对其进行救灾并且各出救点的运力有限的情况，以最小化总的车辆运输费用，最大化救灾效率、各受灾点的救灾满意度，以及各受灾点得到救助的公平性为目标，建立了该问题的多目标混合整数非线性规划模型，并提出了一个基于两层架构协调的迭代式遗传算法进行求解。基于仿真数据的实验结果证明了所提出的模型和算法的有效性。     

Multivariate Cox Hidden Markov models with an application to operational risk

ABSTRACT

Modeling multivariate time-series aggregate losses is an important actuarial topic that is very challenging due to the fact that losses can be serially dependent with heterogeneous dependence structures across loss types and business lines. In this paper, we investigate a flexible class of multivariate Cox Hidden Markov Models for the joint arrival process of loss events. Some of the nice properties possessed by this class of models, such as closed-form expressions, thinning properties and model versatility are discussed in details. We provide the expectation-maximization (EM) algorithm for efficient model calibration. Applying the proposed model to an operational risk dataset, we demonstrate that the model offers sufficient flexibility to capture most characteristics of the observed loss frequencies. By modeling the log-transformed loss severities through mixture of Erlang distributions, we can model the aggregate losses. Finally, out-of-sample testing shows that the proposed model is adequate to predict short-term future operational risk losses.     

公开密钥算法RSA策略及程序实现

随着通信的飞速发展，信息安全显得越来越重要，计算机密码体制的基本思想就是将要保护的信息变成伪装信息，在公开密钥算法提出之前，所有密码系统的解密密钥和加密密钥彼此有着直接的联系，这也是秘密密钥的缺陷所在。为此公开密钥算法RSA算法就顺应而生。这种叫加密算法可用VB程序编程实现。