金融控股集团内部风险传染研究

金融控股集团特有的经济关系形成集团内部错综复杂的经济网络,本文基于集团内部的股权结构和关联交易形成有向网络,构建金融控股集团内部风险传染的模型。研究结果表明:持股对手数量超过某一临界值时,风险被集团成员共同分担,成员仅需承担较小的破产成本,集团稳定;持股对手数量固定时,集团内部风险传染情况与持股比重之间不存在单调关系。集团在持股对手数量和持股比重之间存在权衡,以此减小集团内部风险传播的可能性。此外,当集团成员爆发危机后,关联交易将增大集团成员的损失,从而扩大风险以及风险传播范围。本文为金融控股集团股权分配和关联交易规模提供了理论指导。     

民办高校大学物理演示实验教学浅析

本文从教学实际出发,调查研究了我国民办高校大学物理演示实验的教学现状,分析了开设大学物理演示实验课程的重要性,并对民办高校大学物理演示实验的教学改革与创新提出了几点举措。     

公司权益价值波动率下股本权证的定价方法

传统的股本权证定价模型一般基于公司股票波动率或公司权益价值波动率进行研究。讨论了根据公司权益价值波动率所求得的权证定价模型的一些性质,比较了分别根据公司权益价值波动率和股票价值波动率计算权证价值所得的误差。针对长电权证的实际情况进行实证分析,通过比较传统定价模型与本文的考虑保底摊薄模型定价的结果说明采用公司权益价值波动率所得定价模型的准确性。     

Cryptanalysis and Improvement of Quantum Private Comparison Protocol Based on Bell Entangled States

Recently, Liu et al. [Commun. Theor. Phys. 57 (2012) 583] proposed a quantum private comparison protocol based on entanglement swapping of Bell states, which aims to securely compare the equality of two participants' information with the help of a semi-honest third party (TP). However, the present study points out there is a fatal loophole in Liu et al.'s protocol, and TP can make Bell-basis measurement to know all the participants' secret inputs without being detected. To fix the problem, a simple solution, which uses one-time eavesdropper checking with decoy photons instead of twice eavesdropper checking with Bell states, is demonstrated. Compared with the original protocol, it not only reduces the Bell states consumption but also simplifies the protocol steps.     

Twice-Hadamard-CNOT attack on Li et al.’s fault-tolerant quantum private comparison and the improved scheme

Recently, Li et al. presented a two-party quantum private comparison scheme using Greenberger–Horne–Zeilinger (GHZ) states and error-correcting code (ECC) [Int. J. Theor. Phys. 52, 2818 (2013)], claiming it is fault-tolerant and could be performed in a non-ideal scenario. However, there exists a fatal loophole in their private comparison scheme under a special attack, namely the twice-Hadamard-CNOT attack. Specifically, a malicious party may intercept the other party’s particles and execute Hadamard operations on the intercepted particles as well as on his or her own particles. Then, the malicious party could sequentially perform a controlled-NOT (CNOT) operation between intercepted particles and the auxiliary particles, as well as between his or her own particles and the auxiliary particles prepared in advance. By measuring the auxiliary particles, the secret input will be revealed to the malicious party without being detected. For resisting this special attack, a feasible improved scheme is proposed by introducing a permutation operator before the third party (TP) sends the particle sequences to each participant.     

基于PSM方法的民营企业权力变更R&D效应研究——来自中国上市民营企业的经验数据

本文以中国沪深A股市场实际控制人发生变更的民营企业为研究对象,基于PSM模型实证检验民营企业权力变更引发的企业R&D效应变化。研究结果表明:民营企业权力变更对企业R&D效应具有显著的积极影响,在企业高层领导权变更三年内,R&D投入强度平均增长24.04%;通过分别考察家族企业与非家族企业权力变更对企业R&D效应的影响,发现尽管家族企业R&D投入普遍低于非家族企业,但是家族企业权力变更的企业R&D升级效应明显优于非家族企业,意味着家族企业在代际传承时期的权力变更有利于增强企业创新能力。     

Multiple criteria linear programming model for portfolio selection

The portfolio selection problem is usually considered as a bicriteria optimization problem where a reasonable trade-off between expected rate of return and risk is sought. In the classical Markowitz model the risk is measured with variance, thus generating a quadratic programming model. The Markowitz model is frequently criticized as not consistent with axiomatic models of preferences for choice under risk. Models consistent with the preference axioms are based on the relation of stochastic dominance or on expected utility theory. The former is quite easy to implement for pairwise comparisons of given portfolios whereas it does not offer any computational tool to analyze the portfolio selection problem. The latter, when used for the portfolio selection problem, is restrictive in modeling preferences of investors. In this paper, a multiple criteria linear programming model of the portfolio selection problem is developed. The model is based on the preference axioms for choice under risk. Nevertheless, it allows one to employ the standard multiple criteria procedures to analyze the portfolio selection problem. It is shown that the classical mean-risk approaches resulting in linear programming models correspond to specific solution techniques applied to our multiple criteria model. This revised version was published online in June 2006 with corrections to the Cover Date.     

VRS网络差分系统数据通讯结构设计

为了满足虚拟参考站（VRS）网络差分系统数据传输高可靠、低时延的要求,解决多参考站、多移动站网络通讯带来的软件结构复杂性,提出采用虚拟专用网（VPN）及通用无线分组业务（GPRS）／互联网（Internet）无缝链接技术构建通讯链路,用自适配通信环境（ACE）设计可跨平台、复用性强的网络传输软件框架,基于通过互联网传送差分信息协议（Ntrip）组织规范差分数据传输格式。实验测试表明,该网络差分系统数据传输稳定可靠,延时在2s以内,实时定位精度达到了厘米级。     

Who succeeds in STEM? Elementary girls' attitudes and beliefs about self and STEM

With ongoing underrepresentation of women in STEM fields, it is necessary to explore ways to maintain girls' STEM interest throughout elementary and middle school. This study is situated within the context of Designs in STEM (pseudonym), an out-of-school program that engages urban youth in authentic STEM experiences. Participants were 30 girls attending Designs in STEM in grades four and five. Participants were interviewed about their STEM interest, out-of-school versus in-school STEM learning experiences, and how gender relates to STEM success. Several key findings emerged. First, although students' prior school experiences with mathematics resulted in less positive dispositions toward mathematics than other STEM disciplines, their experiences at Designs in STEM revealed that mathematics could be fun and valuable when used for real-world purposes. Second, students found Designs in STEM to be more engaging and inspiring due to the context and pedagogies employed by Designs in STEM instructors. Third, despite observing girls' behavior that was more aligned with academic success, participants still identified STEM advantages for boys. Finally, participants defined success and intelligence in STEM based on speed and tracking. Discussion focuses on the need to consider how school-based mathematics instruction may serve as a barrier to girls' STEM interest and involvement.