基于区域计算机联锁的CTC系统研究

区域计算机联锁实现了车站联锁、区间闭塞和调度指挥一体化控制,在我国铁路有广阔的应用前景,本文对基于区域计算机联锁的调度集中(CTC)系统进行研究,有实际意义。本文给出一种基于区域计算机联锁的CTC车站系统的结构和方案。系统采用智能化分散自律设计原则,依据列车运行调整计划来自动控制区域范围内车站的列车进路,同时,在列车运行调整计划的基础上,解决了区域范围内车站的列车作业与调车作业在时间与空间上的冲突,实现了列车和调车作业的统一控制。以大秦线的王岭线路所、秦皇岛北站为例,讨论了区域控制后运输组织的变化,详细分析CTC功能的改变,并研究了CTC车站自律机、车务终端、电务终端的相应处理。该方案结构简单、可节省投资;系统运行稳定,可提高运输指挥效率。     

An efficient threshold key-insulated signature scheme

To tackle the key-exposure problem in signature settings, this paper introduces a new cryptographic primitive named threshold key-insulated signature (TKIS) and proposes a concrete TKIS scheme. For a TKIS system, at least k out of n helpers are needed to update a user’s temporary private key. On the one hand, even if up to k−1 helpers are compromised in addition to the exposure of any of temporary private keys, security of the non-exposed periods is still assured. On the other hand, even if all the n helpers are compromised, we can still ensure the security of all periods as long as none of temporary private keys is exposed. Compared with traditional key-insulated signature (KIS) schemes, the proposed TKIS scheme not only greatly enhances the security of the system, but also provides flexibility and efficiency.     

基于粒子群优化反步法的船舶航向控制器设计

考虑到反步法在随机干扰下具有较优的控制效果,利用反步法设计基于Nomoto模型的船舶航向控制器;设计一种基于粒子群优化(Particle Swarm Optimization,PSO)反步法的航向控制器,其能通过优化不确定增益参数来消除部分冗余控制。通过仿真试验比较不同航向控制器的性能。仿真结果表明:粒子群优化反步法航向控制器具有更高的控制精度和更强的鲁棒性。     

粉煤灰在城乡道路水泥混凝土路面中的应用

结合工程实例,阐述了粉煤灰的技术性能,在城乡水泥混凝土路面工程中的实用效果,取得的社会经济效益,同时指出了施工中存在的问题和解决办法。     

Efficient and provably-secure certificateless proxy re-encryption scheme for secure cloud data sharing

In current cloud computing system, large amounts of sensitive data are shared to other cloud users. To keep these data confidentiality, data owners should encrypt their data before outsourcing. We choose proxy reencryption （PRE） as the cloud data encryption technique. In a PRE system, a semi-trusted proxy can transform a ciphertext under one public key into a ciphertext of the same message under another public key, but the proxy cannot gain any information about the message. In this paper, we propose a certificateless PRE （CL-PRE） scheme without pairings. The security of the proposed scheme can be proved to be equivalent to the computational Dire- Hellman （CDH） problem in the random oracle model. Compared with other existing CL-PRE schemes, our scheme requires less computation cost and is significantly more efficient. The new scheme does not need the public key certificates to guarantee validity of public keys and solves the key escrow problem in identity-based public key cryptography.     

发动机冷测试技术在汽车生产中的应用

针对目前应用越来越广泛的发动机装配过程中的在线检测冷测试技术。对发动机冷测试项目及相关流程进行了介绍,同时介绍了与冷测试相配套设施的要求及相关使用情况。     

基于最优滑移率的车辆轨迹跟踪控制研究

为了实现智能车辆最优的轨迹跟踪控制,最大程度的利用滑移率和地面附着系数实现智能车辆的动力学控制,文章提出了考虑滑移率的轨迹跟踪控制方法。根据车辆行驶特性,建立动力学方程,计算运动过程中的轮速和横摆角,并结合滑移率对车辆动力学的影响,基于最优滑移率设计了控制系统,以制动工况为例,实现制动车速工况下的最优控制。基于车辆二自由度模型,运用Matlab建立二维空间整车运动轨迹模型,得到车辆运动仿真轨迹。仿真结果验证了数学模型的准确性和正确性。考虑滑移率和车辆动力学的轨迹跟踪控制更具真实准确,文中数学模型及设计的控制系统对车辆跟踪控制有参考价值。     

航标智能化管理系统研究与设计

航标智能化管理系统研究是推进智慧化航海保障服务体系的重要举措。在系统发展趋势与业务需求分析基础上,整合现有软硬件平台,设计了面向内部管理、海上监控、对外服务三大服务领域的航标智能化管理系统,并探讨了业务数据平台与应用功能平台的实现方法。文中研究成果对于构建与推广智能化、标准化、一体化的航标智能化管理系统,具有重要的参考价值。     

Identity-based key-insulated proxy signature without random oracles

In an identity based proxy signature (IBPS) scheme, a designated proxy signer can generate the signature on behalf of an original signer. Traditional IBPS schemes normally rely on the assumption that private keys are kept perfectly secure. However, due to viruses, worms or other break-ins allowed by operating-system holes, key exposure seems inevitable. To minimize the damage caused by key exposure in IBPS, we propose an identity-based key-insulated proxy signature (IBKIPS) scheme in the standard model, i.e. without random oracles.     

“桑吉”轮油污损害赔偿法律适用问题探析

“桑吉”轮所载货物凝析油,不属于《1992年责任公约》所调整的“持久性油类”范畴,此外其还装载有1900余吨船用燃料油。该案作为世界上首例“凝析油”油船海难事故,因此导致油污损害赔偿法律适用问题并不明朗,适用不同法律可能导致相关方赔偿责任限制差异巨大。探究“桑吉”轮案油污损害赔偿法律适用问题,不仅有助于满足我国现实司法需要,更可为我国乃至世界处理此类油污损害问题提供有益借鉴。文中将从国际公约及国内法角度,对“桑吉”轮油污损害赔偿问题可能涉及的法律适用问题进行探析。