Nonparametric Bayesian inference for ergodic diffusions

The problem of nonparametric drift estimation for ergodic diffusions is studied from a Bayesian perspective. In particular, Gaussian process priors are exhibited that yield optimal contraction rates if the drift function belongs to a smoothness class.     

基于复杂网络演化博弈的绿色消费者对新能源汽车扩散的影响研究

绿色消费行为是绿色产业发展的主要推动力。以市场需求侧与供给侧协调为思路,基于复杂网络演化博弈理论,构建新能源汽车扩散模型,研究绿色消费者对制造商微观决策与宏观新能源汽车扩散的影响。在小世界网络情境下进行仿真分析,结果表明：宏观上,绿色消费者溢价和绿色消费者比例的增加都能够促进新能源汽车扩散,但是二者的微观影响机制不同。绿色消费者溢价的增加总是使得演化稳定状态下所有制造商的平均收益都增加,而绿色消费者比例的增加可能导致所有制造商的平均收益都减少。在产业层面,绿色消费行为对新能源汽车扩散具有积极的促进作用,而在企业层面,绿色消费行为的作用并非总是积极的。因此,一方面,促进新能源汽车扩散需要加强对需求侧的重视。从扩大绿色消费者规模和提高绿色消费者溢价两方面考虑,政府应该通过制定激励机制或加大环保宣传等财税或非财税方式促使消费者环保意识的觉醒。另一方面,新能源汽车制造商应该制定恰当的营销策略促使绿色消费者对新能源汽车产生更多溢价;燃油汽车制造商能够从新能源汽车制造商的营销策略中搭便车,应避免与新能源汽车制造商进行恶性竞争。论文从影响因素和扩散机制两方面拓展了新能源汽车扩散理论研究体系,研究结论...     

股票价格运行的幂律特征及幂律跳跃扩散模型

在Merton提出的跳跃扩散模型的逻辑框架之下,完成了两方面的修正工作:将计数过程由Poisson过程修正为带有幂律性质的更新过程,同时,赋予股票价格运动过程发生跳跃的时间和幅度以幂律分布特征.通过实证研究表明,修正后可以更加准确地描述股票价格的运动过程,同时得到具有尖峰胖尾的收益率分布和波动聚集性.以此为基础可以更加准确地为期权等金融衍生品进行定价,同时也为金融风险管理提供了有效工具.     

Modeling the dynamism of HIV information diffusion in multiplex networks of homeless youth

Cascade and threshold models are widely used to predict information diffusion in social networks, yet their characterization of networks as static and monoplex limit their ability to accurately predict how information propagates in dynamic, multiplex social environments. Using data from a peer-led HIV prevention intervention for homeless youth, we determine whether manipulating the baseline social network by (1) adding ties observed at later time points, and (2) accounting for alternative relational contexts improves each model’s predictive accuracy. Results show that the addition of new ties improves the performance of both models, while substituting the context of interaction yields only minor improvements.     

How to Describe It? Why the Term Coming Out Means Different Things in the United States and France

Drawing on 30 in‐depth interviews with U.S. and French lesbians, gay men, and bisexuals, we find important similarities in how U.S. and French respondents strategically managed the visibility of their sexual identities but differences in the vocabulary used to discuss those experiences. Specifically, all of the Americans used the expression coming out spontaneously while only five French respondents did so. Instead, French respondents typically rejected coming out in favor of other words or expressions. Rather than simple effects of speaking different languages, these differences stemmed from distinct connotations given to the same—widely diffused—expressions within each local context. Unlike their American peers, who saw the expression's origin in their own history and used in everyday lives, most French respondents resisted what they perceived to be an American cultural object imported by the French media. We also find evidence that the meaning of coming out is changing in both contexts such that in the future, the French and Americans may perceive and use it more similarly. This research contributes to our understanding of the intersection between language, meaning, and political context, within a cross‐national setting.     

A Strategy for Opening a New Market and Encroaching on the Lower End of the Existing Market

We identify and analyze a scenario where a firm first opens up what we call a “detached” market, by offering a new product that meets a customer need that is very different from (i.e., detached from) the need met by the old established product. Our analysis builds on the previous studies that describe alternate ways in which a new product might open a new market and ultimately encroach on an existing market. Consider the example of cell phones: They opened up a new detached market by meeting the customer need for mobility, a need very different from the traditional attribute of reception quality. By meeting an important detached need, a new product can sell at a high price, even though it might be woefully deficient with regard to the traditional performance dimension (the reception/coverage of early cell phones was sorely lacking). A person who is a high‐end customer for the old product initially despises the new product as a replacement for the old one but might simultaneously be one of the first customers for the new product because it fills the detached‐market need. Over time, the new product improves along the traditional dimension (e.g., cell phone reception/coverage has dramatically improved), and eventually it becomes a replacement for the old product, encroaching from the lower end upward (the first customers to drop their landlines have been lower‐end customers such as students and apartment dwellers, whereas higher‐end business customers still have landlines in their offices). We call this the detached‐market form of low‐end encroachment and show how it helps explain the conundrum of an expensive “disruptive” innovation. We go on to relate our results to the finding that “willingness to cannibalize” is a key factor in an incumbent firm's growth and survival, and to the “blue ocean strategy.”     

一类(2+1)维非线性扩散方程的对称及不变解

本文首先讨论了一类(2+1)维非线性扩散方程的一般形式并对其进行对称分类,然后利用对称约化得到了(2+1)维非线性扩散方程相应于这些单参数不变群的群不变解.     

Challenges Facing Public Sector Management in an Era of Downsizing,Devolution, Dispersion and Empowerment—and Accountability?

Agencies at all levels of government are facing strong ideological pressures to downsize, devolve, dispense, and empower both employees and recipients of services. These ideological pressures provide many performance advantages, but collectively they threaten historic notions of achieving economy, efficiency, and effectiveness, along with accountability. It has been widely assumed in recent years that advancements in information technology and performance measurement provide adequate replacements for the historic notion that accountability flows up-the-hierarchy to elected officials and the sovereignty. These technologies, however, are not yet able to ensure responsible administration or accountability in many areas of domestic government services. Today's public managers can play leading roles in developing alternative approaches for achieving accountability if they are supported by forward-looking human resources management (HRM) agencies.     

关于气固相催化反应中扩散控制对反应选择性影响的探讨

从定量角度描述气固相催化反应中内外扩散过程对反应选择性（S）的影响,并以两个独立并存的反应类型的内外扩散过程对S的影响为例进行定理讨论。结果表明,采用上述定量的方法,直观明了,更具有说明力,学生易于理解。