价值共创引导乡村旅游价值链重构

［目的］通过充分发挥移动互联时代消费者对于价值链、创新链、产业链构建的作用，实现价值共创视角下乡村旅游价值链的重构，解决乡村旅游产业中消费者需求和产业供给不平衡不充分之间的矛盾，推动乡村旅游高效、有序、协调、综合发展。［方法］基于价值共创理论，通过文献研究法和系统论方法，探索性重构乡村旅游价值链。［结果］（1）价值共创引导下的乡村旅游价值链是由基本价值活动、辅助价值活动和价值共创活动共同组成，通过虚拟价值链和传统价值链的互动与融合，实现乡村旅游价值链的新价值创造。（2）价值共创活动是以虚拟价值链为基本特征，以“产消者”创新社区为表现形式，依托移动互联网时代的先进技术，创新性赋予旅游者产品生产者和旅游消费者的“产消者”双重属性，通过将消费者从传统价值链的幕后拉向幕前，实现乡村旅游价值链重构和价值增值。［结论］价值共创引导的乡村旅游价值链需要依托平台思维、共享思维和创新思维进行建设，以消费者需求为导向形成的价值链的开放和互动对于实现乡村旅游供给侧结构性改革具有重大意义。     

农产品供应链重构风险传导SIR建模与仿真研究

[目的]利用动力学SIR模型模拟农产品供应链重构内生风险传导过程,以期在有效把握核心重构风险传导规律基础上为整体管控重构进程风险提出前瞻性思路。[方法]基于农产品供应链重构风险整体构架和重构进程风险传导复杂网络,以湖北省243家大型连锁超市生鲜农产品供应链2007—2017年重构样本数据为研究对象,建立重构进程内生风险传导SIR模型和规划演化模式,利用Matlab软件对模型仿真得到有效管控状态下演化趋势。[结果]在以战术性重构为主导组织结构战略性重构中进程风险传导安全边际X1s超过50%,决定了其净风险阈α0(i)、β0(i),相应的业务单元和功能模块重构进程风险预警和风险恢复能力提高值是主控指标,对进程风险传导感染率x1(i)和恢复率x2(i)起主导作用。[结论]近年来土地流转驱动农产品供应链重构中组织结构重构整体具有战略性,在以战术性重构为主导风险传导管控中重点应加强业务单元和功能模块重构进程在重构易感状态(S)、感染传播状态(I)管控能力,能有效降低波动幅度。     

刑事涉财产执行中的案外人权益救济——以案外人权益救济程序的当事人构造为视角

刑事涉财产执行程序因采取移送执行模式而被误认为不存在申请执行人，使得刑事涉财产执行程序及其衍生的案外人权益救济程序过分依赖执行法院的职权主义。在刑事附带民事诉讼裁判、追缴或责令退赔违法所得并返还被害人判项、责令被免予刑事处罚的被告人赔偿被害人损失判项的执行程序中，案外人权益救济程序原则上应以被害人为申请执行人，并参照适用民事强制执行程序中的案外人权益救济制度。其他刑事涉财产执行程序应以检察机关为申请执行人。除非出现被执行人逃避执行或者案外人对执行标的提出排除执行请求等特殊情形，作为申请执行人的检察机关通常无须现实参加执行程序。     

Error analysis of finite difference and Markov chain approximations for option pricing

Mijatovi? and Pistorius proposed an efficient Markov chain approximation method for pricing European and barrier options in general one‐dimensional Markovian models. However, sharp convergence rates of this method for realistic financial payoffs, which are nonsmooth, are rarely available. In this paper, we solve this problem for general one‐dimensional diffusion models, which play a fundamental role in financial applications. For such models, the Markov chain approximation method is equivalent to the method of lines using the central difference. Our analysis is based on the spectral representation of the exact solution and the approximate solution. By establishing the convergence rate for the eigenvalues and the eigenfunctions, we obtain sharp convergence rates for the transition density and the price of options with nonsmooth payoffs. In particular, we show that for call‐/put‐type payoffs, convergence is second order, while for digital‐type payoffs, convergence is generally only first order. Furthermore, we provide theoretical justification for two well‐known smoothing techniques that can restore second‐order convergence for digital‐type payoffs and explain oscillations observed in the convergence for options with nonsmooth payoffs. As an extension, we also establish sharp convergence rates for European options for a rich class of Markovian jump models constructed from diffusions via subordination. The theoretical estimates are confirmed using numerical examples.     

Learning from R&D outsourcing vs. learning by R&D outsourcing

We analyze how research and development (R&D) outsourcing influences product innovation. We propose a separation between learning from R&D outsourcing, whereby the firm improves its ability to innovate by using outsourced R&D directly in new products, from learning by R&D outsourcing, whereby the firm indirectly uses outsourced R&D by integrating it with internal R&D to create new products. Building on the knowledge-based view, we argue that learning from R&D outsourcing is likely to have an inverse U-shaped relationship with product innovation, because the initial benefits of using outsourced component R&D knowledge to innovate products is eventually outweighed by the hollowing out of the firm's ability to innovate. In contrast, we propose that learning by R&D outsourcing is likely to have a U-shaped relationship with product innovation, because the initial challenges of integrating internal and external R&D are eventually overcome, resulting in more innovations. Finally, we distinguish between domestic and foreign R&D outsourcing and propose a liability of foreignness in R&D outsourcing as it has a lower impact on new products than domestic R&D outsourcing. The empirical analysis shows that outsourced R&D has an inverted U-shaped relationship with the number of new products, while the interaction between outsourced R&D and internal R&D has a U-shaped relationship with the number of new products. It also shows that domestic outsourced R&D has a higher positive impact on the number of new products than foreign outsourced R&D.     

一种混合多边缘型LDPC码密度进化算法

在二进制输入加性高斯白噪声信道下，研究了基于多边缘型低密度奇偶校验码（Multi-edge Low Density Parity Check，MET-LDPC）的密度进化算法。针对高斯近似算法在前期迭代中的不准确问题，提出了一种改进算法。在分析MET-LDPC码的密度进化的基础上，将全密度进化与高斯近似算法结合，通过设置切换限制条件，弥补早期迭代的不准确，提高编码阈值估计的准确性。仿真结果表明,与MET-LDPC全密度进化算法相比，所提算法可以有效提高编码阈值估计的准确性，对LDPC编码的设计有一定的参考价值。     

“Going natural”: Black women’s identity project shifts in hair care practices

Hair care, a seemingly mundane consumption practice, is packed with sociocultural meanings and constitutes an important realm of identity work for consumers. Drawing upon existing literature on consumer identity projects, this paper investigates the experiences of urban, Black women in Kenya as they disengage from the normative practice of altering their natural hair texture using chemical straighteners (a practice that conforms to Eurocentric beauty ideals of straight, flowing hair), and adopt the non-normative hair care practice of “going natural,” in which they embrace their natural hair texture and hairstyles. This paper traces the historical, sociocultural, and political events that underpin the normative ideology associated with the identity marker of natural Black hair, and how this ideology influences the women’s “going natural” experience. Findings reveal tensions that emerge in the women’s identity project disengagement and reconstruction process, and how the women navigate their position as they reimagine their embodied identity quest.     

美国金融危机压力的来源及其对中国防范金融风险的启示——基于MIMIC模型的实证分析

党的十九大报告指出：“要坚决打好防范化解重大风险攻坚战，其关键又是防范金融风险，包括防范中国系统性金融风险的发生和抵御国际性金融危机传导所带来的外部冲击。”2007年由美国次贷危机演变成的全球性金融危机，至今还在持续影响着部分国家的经济和金融发展。2015年底开始的美国第六轮加息周期和2018年3月中美贸易战的爆发，使得中国的经济发展面临更大的机遇和挑战。本文以次贷危机为背景，基于MIMIC模型对2005—2016年的美国金融危机压力进行了测度，找到压力的来源为外汇储备增长率、出口增长率和实际有效汇率高估三个方面，进而分析其产生的根本原因，最后从三方面提出中国防范化解重大风险的对策和启示。     

Spatial statistical modelling of insurance risk: a spatial epidemiological approach to car insurance

Spatial models, such as the Besag, York and Mollie (BYM) model, have long been used in epidemiology and disease mapping. A common research question in these subjects is modelling the number of disease events per region; here the BYM models provides a holistic framework for both covariates and dependencies between regions. We use these tools to assess the relative insurance risk associated with the policyholders geographical location. A Bayesian modelling approach is presented and an elastic net is used to reduce the large number of possible geographic covariates. The final inference is performed using Integrated Nested Laplace Approximation. The model is applied to car insurance data from If P&C Insurance together with spatially referenced covariate data of high resolution, provided by Insightone. The entire analysis is performed using freely available R-packages. Including spatial dependence when modelling the number of claims significantly improves on the result obtained using ordinary generalised linear models. However, the support for adding a spatial component to the model for claims cost is weaker.