Defender–Attacker Games with Asymmetric Player Utilities

The presence of strategic attackers has become an important factor in the security and protection of systems, especially since the 9/11/2001 attacks, and considerable efforts have been dedicated to its study. When defending against the strategic attacker, many existing studies assume that the attacker would seek to minimize the defender's utility, which implies that the defender and attacker have symmetric utilities. However, the attacker's objective is determined by its own valuation of the system and target of the attack, which is not necessarily consistent with the defender's utility. If the attacker unexpectedly targets a different utility, then the defense strategy might no longer be optimal. In particular, the defense strategy could be inferior if the attacker's utility is not known to the defender. This study considers a situation where the defender's utility is the system survivability and the attacker's utility is the expected number of destroyed elements in the system. We investigate possible attack strategies under these two different utilities and compare (a) the conservative defense strategy when the attack utility is unknown to the defender with (b) the optimal defense strategy when the attack utility is known to the defender. We show that the conservative protection strategy is still optimal under asymmetric utilities when the contest intensity is smaller than one.     

Get Full Text Research and the Search for Appropriate Copies

Abstract

A group of the largest academic publishers has launched a new service to simplify access to full-text research for users of discovery services and scholarly collaboration platforms. While this service aims to provide easy access to full-text articles using article-level entitlement information linked to institutions through Seamlessaccess.org, it also introduces ambiguity. The service allows for publishers to direct users to alternative versions when a full-text entitlement is not found for the user, though users may already be entitled to full text through providers that do not participate in the service. Depending on specific implementations, this could lead to further confusion and make it more difficult for users to find an appropriate copy.     

网络爬虫技术的研究

随着信息技术的发展,特别是互联网技术的不断普及,网上信息数量成指数级增长。如何准确有效地从海量信息中检索出所需的信息,成为一个重要而迫切的研究课题。本文对网络爬虫的搜索策略进行了简要分析,比较各算法的优缺点,总结提升搜索效率的因素,提出了新一代搜索引擎的期望,以便更快获取自己需要的信息。     

Improving OpenURL Menus: User Testing of Revisions to SFX® Menus

Twenty-one volunteers tested the usability of revisions to the Texas A&M University Libraries' SFX® OpenURL link resolver menus, including the addition of Ex Libris' new bX™ recommendation service and a plug-in which pulls additional information about the journal into the menu. The volunteers also evaluated the quality and desirability of the bX recommendations and discussed their preferences for help options and full-text format. Results of the usability testing are reported along with the resultant menu changes. This study will be of interest to librarians implementing or redesigning OpenURL menus as well as those interested in the user experience.     

Variable selection for multivariate generalized linear models

Generalized linear models (GLMs) are widely studied to deal with complex response variables. For the analysis of categorical dependent variables with more than two response categories, multivariate GLMs are presented to build the relationship between this polytomous response and a set of regressors. Traditional variable selection approaches have been proposed for the multivariate GLM with a canonical link function when the number of parameters is fixed in the literature. However, in many model selection problems, the number of parameters may be large and grow with the sample size. In this paper, we present a new selection criterion to the model with a diverging number of parameters. Under suitable conditions, the criterion is shown to be model selection consistent. A simulation study and a real data analysis are conducted to support theoretical findings.     

社会主义社会的基本矛盾与构建和谐社会

社会主义生产关系与生产力的基本适应、社会主义上层建筑与社会主义经济基础的基本适应,是社会主义制度具有优越性、生命力的内在根据,为构建和谐社会奠定了经济、政治基础。社会主义制度具有解决自身矛盾的本质力量,是和谐社会能有生机活力的源泉。社会主义社会中,生产关系与生产力、上层建筑与经济基础之间还有不适应、不和谐的相互矛盾的方面,总体来看,这种矛盾是非对抗性的。构建和谐社会的科学概念是党的最高纲领与最低纲领的动态结合点,发挥构建和谐社会的政治驱动作用会推动社会主义事业朝着共产主义方向稳步前进。     

乡村振兴背景下农业产业化对农民收入的影响研究 ——基于S省M县调研数据

乡村振兴战略的提出为顺利解决农业经济发展问题、促进农业产业化进程和解决农民收入问题提供了政策参考的蓝本,也促使农业产业化成为解决农民增收问题的主要落脚点。该研究从农业产业化前、中、后期三阶段出发,综合考虑农民个人禀赋、政府政策、是否参加合作社及产后重点项目等维度,构建了农业产业化改善农民增收问题的理论框架,利用调研数据和二元logistic模型进行实证研究。结果表明：农业产业化能显著改善农民收入问题。作为农业产业化的典型代表,合作社在增加农民收入方面发挥着显著的积极作用,尤其是参与合作社产后重点项目这一农业产业化深化行为,更会促使农民增收。相对而言,文化程度较高、有技能、风险承受能力较强的农民收入增加的可能性较高。     

纵向差异下的连接外部性和网络结构分析

在寡头竞争的市场环境里,相互竞争的企业通常会与竞争对手建立连接,从而影响他们在产品市场上竞争的方式。本文我们建立两阶段博弈模型研究企业建立连接的激励以及由此而形成的网络结构形态。在博弈的第一期,具有纵向差异化的企业决定是否与其竞争对手建立连接;企业观察到连接结果后在第二期进行价格竞争。本文的分析显示均衡网络结构与连接效应、连接成本和消费者偏好有关,均衡网络可能仅是一个企业与其它所有企业建立连接的星型网络结构,也可能是没有任何企业建立连接的空网络结构。本文还分析了均衡网络和社会有效网络之间的关系,发现均衡网络和社会有效网络并不总是一致的,从社会计划者的角度看,企业建立连接可能存在激励不足,因此公共政策应该鼓励企业建立连接。     

城市路网运输性能退化成本评估模型

路网的运行受到诸多因素的影响而使得路网运输性能发生退化,分析了路网运输性能退化的影响因素和作用机理,给出了路网运输性能退化及退化的极端情况路段失效的成本分析过程框架.基于BPR路阻函数和用户均衡分配理论分析路网运输性能退化的成本函数,建立了拥堵情况下城市路网路段失效的成本评估模型.最后,通过实例分析了路网运输性能退化对出行成本影响的变化规律,给出了路网运输性能退化的极端情况路段失效成本评估的具体过程,研究表明路网运输性能退化对出行成本具有很大的影响,二者成显著的正相关关系.