Multiparty simultaneous quantum identity authentication with secret sharing

Two multiparty simultaneous quantum identity authentication (MSQIA) protocols based on secret sharing are presented. All the users can be authenticated by a trusted third party (TTP) simultaneously. In the first protocol, the TTP shares a random key K with all the users using quantum secret sharing. The ith share acts as the authentication key of the ith user. When it is necessary to perform MSQIA, the TTP generates a random number R secretly and sends a sequence of single photons encoded with K and R to all the users. According to his share, each user performs the corresponding unitary operations on the single photon sequence sequentially. At last, the TTP can judge whether the impersonator exists. The second protocol is a modified version with a circular structure. The two protocols can be efficiently used for MSQIA in a network. They are feasible with current technology. Supported by the National Basic Research Program of China (973 Program) (Grant No. 2007CB311100), the National High Technology Research and Development Program of China (Grant Nos. 2006AA01Z419 and 20060101Z4015), the Major Research Plan of the National Natural Science Foundation of China (Grant No. 90604023), the Scientific Research Common Program of Beijing Municipal Commission of Education (Grant No. KM200810005004), the Scientific Research Foundation for the Youth of Beijing University of Technology (Grant No. 97007016200701), the National Research Foundation for the Doctoral Program of Higher Education of China (Grant No. 20040013007), the National Laboratory for Modern Communications Science Foundation of China (Grant No. 9140C1101010601), and the Doctor Scientific Research Activation Foundation of Beijing University of Technology (Grant No. 52007016200702)     

延迟效应影响下的产学研协同创新知识共享研究

在高校和企业组成的产学研协同创新知识共享体系中,考虑成员的知识共享策略均存在延迟效应时的影响,构建了基于双延迟效应的动态微分模型。运用极大值原理,得到了协同创新主体在集中和分散两种决策下的最优知识共享策略、最优收益和体系的知识水平。研究发现:延迟时间的存在对高校和企业的知识共享策略具有负面效应,且均低于发生即时效应的情形;集中式决策并不总是优于分散式决策,两个延迟时间在满足一定的条件时,选择集中式决策为最优,否则双方企业将追求自身利益最大化而选择分散式决策;分散决策下,利润分配比例达到一定条件时,企业才愿意为高校提供补贴。且高校的知识共享延迟时间增加时,企业将提高该补贴比例。补贴比例越大,高校的知识共享水平越高,但对企业的知识共享策略没有影响。     

A New Approach for Visual Cryptography

Visual cryptography is to encrypt a secret image into some shares (transparencies) such that any qualified subset of the shares can recover the secret visually. The conventional definition requires that the revealed secret images are always darker than the backgrounds. We observed that this is not necessary, in particular, for the textual images.In this paper, we proposed an improved definition for visual cryptography based on our observation, in which the revealed images may be darker or lighter than the backgrounds. We studied properties and obtained bounds for visual cryptography schemes based on the new definition. We proposed methods to construct visual cryptography schemes based on the new definition. The experiments showed that visual cryptography schemes based on our definition indeed have better pixel expansion in average.     

强制减排规制下基于碳减排利润增量分享契约的供应链协调研究

碳减排会增加制造商的成本,导致批发价和零售价提高,从而抑制市场需求。以此为背景,本文针对由一个制造商和一个零售商组成的供应链,研究了强制减排规制下考虑消费者低碳偏好时的供应链决策与协调。通过设计碳减排利润增量分享契约协调制造商和零售商的决策,实现帕累托改进,利用Rubinstein讨价还价模型最终确定减排利润分享比例。研究发现,实施碳减排利润分享契约能有效提高零售商的订货量,并降低批发价格;制造商的利润随着消费者低碳意识提高而提高;当净化率较低时,零售商的利润随消费者低碳意识提高而提高;当净化率较高时,零售商的利润随消费者低碳意识提高而降低;最后,论文通过数值模拟验证了碳减排利润分享契约的有效性。     

MOOC资源的有效利用 ——基于SPOC的无机及分析化学教学改革

In view of the increasing quantity of MOOC curriculum construction and the utilization of MOOC resources, this paper puts forward how to efficiently make use of MOOC resources through deepening curriculum teaching reform. In this paper, the problems in MOOC teaching are summarized, and then the SPOC course is introduced. Along with introducing SPOC course, taking the course of inorganic and analytical chemistry in Huazhong Agricultural University as an example, four main functions of SPOC are expounded emphatically which include solving the problem of cultivating students' autonomous learning ability, solving the problem of obtaining knowledge from MOOC in a piecemeal way, solving the concern about the effect of online learning and solving the low participation of MOOC. It is concluded that the course of SPOC is an important way to make good use of MOOC. It is suggested that the co-construction and sharing of MOOC should be strengthened to enhance the efficiency of MOOC.     

新工科背景下分析化学实验室开放共享新模式的探索*

通过分析实验室仪器设备开放共享管理现状,阐述了当前存在的主要问题,进而提出了“动静结合”“虚实结合”的开放共享新模式,并提出了完善管理制度、合理优化资源、加强实验人才队伍建设以及运用数字化平台等一系列管理对策。     

工科特色普通化学课程的多元一体化教学探索

基于卓越工程师的人才培养要求,提出了工科特色普通化学课程的多元一体化教学新模式。这一教学模式是将同济大学普通化学国家资源共享课与基于MOOC/SPOC等在线课程的学生自主学习与教师主导的课堂讨论以及相关专业前沿科学拓展相结合,提高了大学生的化学素质修养,开阔了学生认识科技前沿的眼界,培养了学生融会贯通地分析问题的能力。     

Strategy for Molecular Design of Photochromic Diarylethenes Having Thermal Functionality

Thermal reactivities of photochromic diarylethene closed‐ring isomers can be controlled by the introduction of substituents at the reactive positions. Diarylethenes having bulky alkyl groups undergo thermal cycloreversion reactions. When bulky alkoxy groups are introduced, the diarylethenes have both thermal cycloreversion reactivities and low photocycloreversion quantum yields. Such photochromic compounds can be applied to thermally reusable photoresponsive‐image recordings. The thermal cycloreversion reactivity of the closed‐ring isomers can be evaluated using specific steric substituent constants and be correlated with the parameters. By introduction of trimethylsilyl or methoxymethyl groups at the reactive positions, the diarylethene closed‐ring isomers undergo thermal irreversible reactions to produce by‐products at high temperatures. These diarylethenes may be useful for secret‐image recordings. Furthermore, thiophene‐S,S‐dioxidized diarylethenes having secondary alkyl groups at the reactive positions undergo thermal by‐product formation reactions, in addition to the photostability of the colored closed‐ring isomers. Such materials may be used for light‐starting thermosensors. The thermal by‐product formation reactivity can be evaluated by the specific substituent constants and theoretical calculations of quantum chemistry. These results supply the strategy for the molecular design of the photochromic diarylethenes having thermal functionality.

     

Mean sojourn times for phase-type discriminatory processor sharing systems

In a discriminatory processor sharing (DPS) queueing model, each job (or customer) belongs to one out of finitely many classes. The arrival processes are Poisson. Classes differ with respect to arrival rates and service time distributions. Moreover, classes have different priority levels. All jobs present are served simultaneously but the fraction of the server’s capacity allocated to each one of them is proportional to their class priority parameter (while the total capacity is of course fixed).     

收益共享的寄售契约下供应商生产成本谎报行为分析

在收益共享寄售契约下的两级供应链中,供应商向零售商报告其生产成本;零售商根据供应商报告的生产成本,决定零售商的收益分配比例;供应商决定零售价格和生产数量,并且保持产品的所有权.由于信息不对称,供应商可能谎报其生产成本.作者应用博弈论分析了供应商谎报行为对供应链及其成员决策及绩效的影响.利用解析的方法得出一些理论结果:零售价格在信息对称时小于生产成本信息不对称时;订货数量在信息对称时大于生产成本信息不对称时;零售商的利润分配比例在信息对称时大于生产成本信息不对称时.供应商的谎报行为使其自身利润增加,使零售商和供应链的利润减少.