“Big Brother’s Bigger Brother”: The Visual Politics of (Counter) Surveillance in Baltimore

In 2016, without the knowledge of its citizens, Baltimore City Police deployed a military aerial surveillance technology called Wide Area Motion Imagery (WAMI), which can track the movements of every person in public view over the entire city. Though the trial of the “spy plane,” as the program was dubbed, quickly ended in scandal, organizers from Baltimore’s low-income minority neighborhoods successfully rebooted the program in 2020, this time framing WAMI partly as a tool of “sousveillance” (watching “from below”) that can track the movements of police officers. The paper shows how organizers “rebranded” WAMI around two conceptions of sousveillance—“citizen-centered” and “state-centered”—creating an unlikely coalition of supporters from both pro- and anti-policing sides of the criminal justice reform debate. But while the renewed program has vowed to be a “Big Brother” to the state, it will continue to be used for traditional surveillance, raising troubling questions about privacy. The article sheds light on the politics of watching and being watched in the era of technology-driven criminal justice reform.     

广义ATO下基于多种团购模型的供应链协调

针对由多个供应商、单个制造商和零售商所组成的广义按订单装配式供应链，在上游多个供应商不确定的零部件（或商品）供应以及下游客户不确定的需求的环境下，首先分析基本模型中团购前后的零售商和制造商的利润变化，然后提出了团购的标准模型和协调模型，并比较三种不同的团购模型对各成员以及全局供应链绩效的影响。通过数学推导证明和仿真数据算例分析，结果表明：零售商自发的团购基本模型总是对制造商有利，而对零售商的好处是有限的；由制造商主导的团购标准模型在满足一定条件时是优于团购基本模型的，但有使得零售商甚至制造商自身受到损失的可能；而集中决策下的团购协调模型能够提升全局供应链的期望利润，实现渠道的帕累托改善，但协调的效果会受到团购客户组成结构的限制。     

考虑消费者双重偏好的低碳供应链减排策略研究

为了削弱传统零售商在渠道博弈中的垄断地位，制造商尝试建立在线渠道与零售商展开竞争。本文在考虑消费者低碳偏好的基础上，又将消费者的渠道偏好进行区分，通过不同决策模式的对比及数值算例分析，寻求低碳供应链最优的减排边界。研究表明：1分散决策时，制造商的低碳决策会受消费者渠道偏好的影响；集中决策时，制造商的低碳决策保持不变。2不同决策模式的减排边界由渠道偏好决定，渠道偏好较大时，分散决策的减排边界更高；渠道偏好较低时，集中决策的减排边界更高；渠道偏好中立时，两者的减排边界相同。3制造商可以通过升级低碳技术、实行低碳化管理等方式降低减排成本，同时通过低碳产品认证、广告宣传等方式提高消费者对低碳产品的认可程度。     

三级装备制造业供应链质量管理行为研究

作为我国工业化建设和国民经济发展的根本保证，供应链环境下装备制造企业的产品质量问题受到了广泛关注。本文重点考虑产品质量对供应链收益的影响，运用微分对策理论研究由单一制造商、单一部件供应商和单一零件供应商构成的三级装备制造业供应链质量管理行为的协调问题。通过对比Nash非合作博弈和Stackelberg主从博弈两种分散式决策模式及集中式决策模式下协同合作博弈的均衡结果，得到相关结论，并利用算例进行验证。研究表明，①分散式决策下，制造商的质量管理行为相同，但相比于Nash非合作博弈，Stackelberg主从博弈能够改善部件供应商和零件供应商的质量管理行为，提升供应链成员的收益水平；②集中式决策下，供应链成员的质量管理行为达到最优，系统整体收益实现最大。研究结论为装备制造业供应链成员间质量管理战略联盟的构建提供了理论依据。     

信息不对称下价格随机的应急数量折扣契约研究

以市场需求和市场价格随机波动的二级供应链为研究对象，寻找其在信息不对称条件下绩效优化的路径。通过显示原理分别构建生产成本和销售成本信息不对称时应急供应链的数量折扣契约模型，得到最优订货量与最佳批发价策略。通过具体的算例加以验证，分析了信息不对称程度对供应链上成员及整个供应链绩效的影响。研究结果表明：当突发事件造成市场价格随机波动和市场需求变化时，供应链上的跟随者能从隐瞒私人信息中获利。但当市场需求增大时，整个供应链绩效受损，反之则反是。这与以往研究在市场需求随机、市场价格固定和信息不对称条件下的结论迥异。     

Then press enter: digital payment technology and the history of telephone interface

The internet and other digital networks in the U.S. (and beyond) remain essentially an upgrade of the national telephone network built by AT&T over the first half of the twentieth century, and digital payment remains tethered to telephony at the level of infrastructure. Telephone history also continues to inform digital payment at the level of interface. Debit card readers feature a keypad nearly identical to those introduced (also by AT&T) to the dialling public a half-century ago on touch-tone telephones. In this essay I highlight the development of the touch-tone keypad as a transformative payment technology. There have been three great leaps forward in the history of telephone interface: the dial, the keypad and the touch screen. Each corresponds to a period of technological transformation in the telephone industry and society more broadly: the rotary dial and automation, touch-tone keypads and digitization, and touch screens and computerization. The successful careers of the dial and the keypad, especially when read in tandem, suggest that touch screens will alter the everyday economics of retail payment even more radically than its predecessors. I also describe a broader trajectory of digital naturalization, whereby telephone numbers have proliferated into a personal identification number, passwords and a plethora of personalized information. Payments increasingly circulate today as subsets of personal information within the vast sea of big data. Payment apps are demonstrating a capacity to reorganize retail transactions on a scale as vast as any technology since the cash register. The history of retail payment finds the point of sale heading from the till into shoppers’ pockets. As a result, consumers are increasingly shouldering the costs of purchasing, maintaining, upgrading and securing the technology used for everyday transactions.     

On Hotelling’s T2 test in a special paired sample case

In a special paired sample case, Hotelling’s T² test based on the differences of the paired random vectors is the likelihood ratio test for testing the hypothesis that the paired random vectors have the same mean; with respect to a special group of affine linear transformations it is the uniformly most powerful invariant test for the general alternative of a difference in mean. We present an elementary straightforward proof of this result. The likelihood ratio test for testing the hypothesis that the covariance structure is of the assumed special form is derived and discussed. Applications to real data are given.     

Application of a non-homogeneous Markov chain with seasonal transition probabilities to ozone data

In this work, we assume that the sequence recording whether or not an ozone exceedance of an environmental threshold has occurred in a given day is ruled by a non-homogeneous Markov chain of order one. In order to account for the possible presence of cycles in the empirical transition probabilities, a parametric form incorporating seasonal components is considered. Results show that even though some covariates (namely, relative humidity and temperature) are not included explicitly in the model, their influence is captured in the behavior of the transition probabilities. Parameters are estimated using the Bayesian point of view via Markov chain Monte Carlo algorithms. The model is applied to ozone data obtained from the monitoring network of Mexico City, Mexico. An analysis of how the methodology could be used as an aid in the decision-making is also given.     

Independent attributes control chart for Markov-dependent processes

Statistical process monitoring (SPM) is a very efficient tool to maintain and to improve the quality of a product. In many industrial processes, end product has two or more attribute-type quality characteristics. Some of them are independent, but the observations are Markovian dependent. It is essential to develop a control chart for such situations. In this article, we develop an Independent Attributes Control Chart for Markov Dependent Processes based on error probabilities criterion under the assumption of one-step Markov dependency. Implementation of the chart is similar to that of Shewhart-type chart. Performance of the chart has been studied using probability of detecting shift criterion. A procedure to identify the attribute(s) responsible for out-of-control status of the process is given.     

网络视频实时在线评论用户认可度的影响因素

目前，网络视频实时在线评论激增带来的信息爆炸，使实时在线评论信息管理成为重要议题。以往对实时在线评论的研究多集中于个人行为结果方面，而缺乏对实时在线评论信息管理问题的关注；同时，现有视频网站对实时在线评论信息的管理也存在诸多局限。以爱奇艺视频网站热度榜中的电影为样本，基于信息质量维度框架并采用Tobit模型对实时在线评论用户认可度的影响因素进行研究，结果发现：实时在线评论的新颖性、相似性、情感倾向性和信息丰富性，均对实时在线评论的用户认可度存在显著影响，其中新颖性和相似性影响作用最大。视频网站可以据此进一步强化实时在线评论管理，改善用户的体验，保持用户的粘性。