Secure and efficient digital rights management mechanisms with privacy protection

In the Internet or cloud computing environments, service providers provide more and more content services. Users can use these convenient content services in daily life. The major data of the user are maintained by the service providers except that some personal privacy data are stored at the client device. An attacker may try to invade the systems, and it will cause the damage of users and service providers. Also, users may lose their mobile devices and then it may cause the data disclosure problem. As a result, the data and privacy protection of users become an important issue in these environments. Besides, since many mobile devices are used in these environments, secure authentication and data protection methods must be efficient in these low resource environments. In this paper, we propose an efficient and privacy protection digital rights management （DRM） scheme that users can verify the valid service servers and the service servers can ensure the legal users. Since the key delegation center of the third party has the robust security protection, our proposed scheme stores the encrypted secret keys in the key delegation center. This approach not only can reduce the storage space of the user devices, but also can recover the encrypted secret keys in the key delegation center when a user loses her/his devices for solving the device losing problem.     

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主要讨论基于用户平衡原则的交通网络优化问题。这些问题大致上可以分为二大类:一类是涉及到确定性用户平衡原则；另一类是考虑随机性用户平衡原则。众所周知，运筹学中的双层规划模型能够完美地刻画这些问题，但是所建立的双层优化模型往拄属于不可微优化问题的范畴，这就给设计有效的算法带来了很大困难.此文首先从模型和算法的角度总结了有关这类问题已有的研究成果，接着介绍有关这方面的最新的研究进展，即如何把用户基于平衡原则下的交通网络优化问题的双层规划模型统一地转换为一个连续可微的单层最优化问题，并设计统一的算法。作为统一的算法方面的研究，我们可以看到增广的拉格朗日方法可以用来解上述的第一类问题，而基于灵敏度的分析的序列二次规划方法完全有能力解上述的第二类问题。     

基于多目标规划的公共交通调度算法与仿真

运用了多目标规划方法建立了公交车辆配置模型，并且生成了可实现计算机仿真的算法。在模型仿真中，力求达到经济效益和社会效益双赢。为了易于操作，在模型求解时，采取化多目标为单目标，最终实现总目标最大。文中通过充分利用公交公司客流调查数据，运用统计学、运筹学等科学方法以及计算机仿真，生成了公交调度表。该优化系统可有效提高公交运营管理水平，且易于实现。     

物流网络选址与路径优化问题的模型与启发式解法

以商品从供应商,经过物流中心(或配送中心),配送到最终用户的整个过程中所产生的费用最小化为目标函数,提出了求解供应商的最佳位置与数量、配送中心的最佳位置与数量以及从配送中心到最终用户的最佳配送路径优化问题,建立了问题的数学模型,利用传统启发式算法与模拟退火法开发了问题求解的混合启发式解法,并利用人工生成数据和实例进行了计算验证。对于小规模问题,通过与数理规划软件所求得的最优解进行比较可以看出,所提出的数学模型可以准确地描述此类问题,所提出的混合启发式解法能够在短时间内求解问题,并得到非常接近于最优解的近似解;对于大规模问题,虽然无法求得最优解进行比较,但从实例计算结果来看,所求解也是较好的,因此可以认为所提出的解法是有效和良好的,具有较高的实用价值。     

Geometrical design of blade＇s surface and boundary control of Navier-Stokes equations

In this article a new principle of geometric design for blade＇s surface of an impeller is provided. This is an optimal control problem for the boundary geometric shape of flow and the control variable is the surface of the blade. We give a minimal functional depending on the geometry of the blade＇s surface and such that the flow＇s loss achieves minimum. The existence of the solution of the optimal control problem is proved and the Euler-Lagrange equations for the surface of the blade are derived. In addition, under a new curvilinear coordinate system, the flow domain between the two blades becomes a fixed hexahedron, and the surface as a mapping from a bounded domain in R2 into R3 , is explicitly appearing in the objective functional. The Navier-Stokes equations, which include the mapping in their coefficients, can be computed by using operator splitting algorithm. Furthermore, derivatives of the solution of Navier- Stokes equations with respect to the mapping satisfy linearized Navier-Stokes equations which can be solved by using operator splitting algorithms too. Hence, a conjugate gradient method can be used to solve the optimal control problem.     

Strong key-insulated signature in the standard model

The only known construction of key-insulated signature (KIS) that can be proven secure in the standard model is based on the approach of using double signing. That is, the scheme requires two signatures: a signature with a master key and a signature with the signer’s secret key. This folklore construction method leads to an inefficient scheme. Therefore it is desirable to devise an efficient KIS scheme. We present the first scheme with such a construction. Our construction derives from some variations of the Waters’ signature scheme. It is computationally efficient and the signatures are short. The scheme is provably secure based on the difficulty of computational Diffie-Hellman (CDH) problem in the standard model.     

基于多中心车辆路径问题的收益分配优化研究

针对多中心车辆路径优化过程中配送中心间合作收益分配不均衡的问题,引进物流服务提供商作为协调者促成配送中心间形成合作联盟.首先,以多中心共同配送总成本最少为目标建立数学模型;其次,应用客户点聚类方法形成初始线路,并设计了GA-PSO混合算法进行线路优化;然后,运用MCRS(Minimum Cost-Remaining Saving)法、Shapley法、比例最小核心法、弱最小核心法和最小核心法分别求解多中心收益分配模型,并应用联盟稳定性方法选择最优收益分配策略;最后,应用严格单调路径方法,以物流服务提供商收益最大化为目标,研究联盟合作序列形成过程和多个联盟的存在形式,并进行了实例验证.结果表明,本文方法有利于促进配送中心间形成联盟,并可应用到以多中心车辆路径优化为基础的物流运输网络合作联盟形成、拆分及网络优化的过程中.     

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.     

Keyword search encryption scheme resistant against keyword-guessing attack by the untrusted server

The user data stored in an untrusted server, such as the centralized data center or cloud computing server, may be dangerous of eavesdropping if the data format is a plaintext. However, the general ciphertext is difficult to search and thus limited for practical usage. The keyword search encryption is a helpful mechanism that provides a searchable ciphertext for some predefined keywords. The previous studies failed to consider the attack from the data storage server to guess the keyword. This kind of attack may cause some critical information revealed to the untrusted server. This paper proposes a new keyword search encryption model that can effectively resist the keyword-guessing attack performed by the untrusted data storage （testing） server. The testing （query） secret is divided into multiple shares so that the security can be guaranteed if the servers cannot conspire with each other to retrieve all shares of the secret.     

Network lifetime global optimization for multi-source and single-sink topology in wireless sensor networks

The multi-source and single-sink (MSSS) topology in wireless sensor networks (WSNs) is defined as a network topology, where all of nodes can gather, receive and transmit data to the sink. In energy-constrained WSNs with such a topology, the joint optimal design in the physical, medium access control (MAC) and network layers is considered for network lifetime maximization (NLM). The problem of integrating multi-layer information to compute NLM, which involves routing flow, link schedule and transmission power, is formulated as a non-linear optimization problem. Specially under time division multiple access (TDMA) scheme, this problem can be transformed into a convex optimization problem. To solve it analytically we make use of the property that local optimization is global optimization in convex problem. This allows us to exploit the Karush-Kuhn-Tucker (KKT) optimality conditions to solve it and obtain analytical solution expression, i.e., the globally optimal network lifetime (NL). NL is derived as a function of number of nodes, their initial energy and data rate arrived at them.Based on the analysis of analytical approach, it takes the influence of data rates, link access and routing method over NLM into account. Moreover, the globally optimal transmission schemes are achieved by solution set during analytical approach and applied to algorithms in TDMA-based WSNs aiming at NLM on OMNeT<++> to compare with other suboptimal schemes.     

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建设现代物流系统要求有关决策部门必须充分考虑可持续发展的因素.基于这个原因，本文建立了可持续发展条件下的物流中心选址双层规划模型，其中上层规划是从系统规划者的角度出发使选址总费用最小，而下层规划为考虑各物流中心相互影响条件下的空间价格平衡的变分不等式模式，与此同时还考虑了污染附加费的征收标准，使其满足环境质量要求.最后设计了基于遗传算法的求解算法，并用一个算例说明了本文所提出的可持续发展条件下物流选址优化模型和算法的应用情况.     

Nonlinear Modeling and Neuro-Fuzzy Control of PEMFC

The proton exchange membrane generation technology is highly efficient, and clean and is considered as the most hopeful “green” power technology. The operating principles of proton exchange membrane fuel cell （PEMFC） system involve thermodynamics, electrochemistry, hydrodynamics and mass transfer theory, which comprise a complex nonlinear system, for which it is difficult to establish a mathematical model and control online. This paper analyzed the characters of the PEMFC; and used the approach and self-study ability of artificial neural networks to build the model of nonlinear system, and adopted the adaptive neural-networks fuzzy infer system to build the temperature model of PEMFC which is used as the reference model of the control system, and adjusted the model parameters to control online. The model and control were implemented in SIMULINK environment. The results of simulation show the test data and model have a good agreement. The model is useful for the optimal and real time control of PEMFC system.     

Focusing azimuth-invariant bistatic synthetic aperture radar data based on a polynomial model

In this paper, a focusing approach is presented to widen the use of efficient monostatic imaging algorithms for azimuth-invariant bistatic synthetic aperture radar (SAR) data. The bistatic range history is modeled by a polynomial of azimuth time. Using this model, an analytic form of the signal spectrum in the 2D frequency domain is derived, and a simple single-valued relation between the transmitter and receive ranges is established. In this way, a lot of monostatic image formation algorithms can be extended for the bistatic SAR data, and a bistatic chirp scaling algorithm is developed as an application of the new approach. This algorithm can be used to process the azimuth-invariant bistatic configuration where the transmitter and receiver platforms are moving on parallel tracks with the same velocity. In addition, some simulation results are given to demonstrate the validity of the proposed approach.     

信号控制模型中利益分配问题的研究

设计了一个平衡约束条件下信号控制与平衡网络设计组合问题的多目标规划模型，然后使用效用函数法将有双目标的上层优化问题转化为一个单目标优化问题．在这种情况下，该模型变成一个标准的双层规划模型。并利用全局优化方法模拟退火算法和惩罚函数法相结合求解．     

大型主题活动客流组织仿真评价及优化研究

为定量化评价大型主题活动期间行人交通系统规划、设计与管理的合理性,从实际工程应用出发,构建以Legion行人交通仿真软件为基础的客流组织评价及优化方法。该方法以设施服务水平为主要评价指标,包含基础数据调查与分析、模型构建与参数标定、仿真结果输出与分析、整体及局部优化等关键步骤。将其应用于第九届中国(北京)国际园林博览会客流组织方案的评价与优化,通过采取优化措施使园区高密度区域的客流比例从13%降至5%。该方法对于定量评价行人设施规划、设计及不同客流组织方案的实施效果具有良好的适用性。     

考虑公平与效率目标的城乡配送中心排队选址模型

为解决随机需求下的城乡配送中心选址问题,实现物流服务的效率与公平,结合排队论构建了需求转移规则下的排队选址模型.为体现城乡客户需求特征差异,构建时 间满意度函数作为服务水平的衡量指标.将客户与配送中心看作M/M/p 排队系统,采用需求可转移的排队规则,运用超立方模型计算配送中心的可用概率.目标函数包括嫉妒最小、基尼系数最小及字典序最大等3 类公平目标,以及覆盖需求量最大、满意度最大两类 效率目标.设计禁忌搜索算法求解,通过算例对模型和算法进行验证.结果表明,P 中位模 型下效率最优,最小嫉妒目标下公平最优,而最大字典序目标可以兼顾公平与效率.     

Bit stream oriented enumeration tree pruning algorithm

Packet analysis is very important in our digital life. But what protocol analyzers can do is limited because they can only process data in determined format. This paper puts forward a solution to decode raw data in an unknown format. It is certain that data can be cut into packets because there are usually characteristic bit sequences in packet headers. The key to solve the problem is how to find out those characteristic sequences. We present an efficient way of bit sequence enumeration. Both Aho-Corasick (AC) algorithm and data mining method are used to reduce the cost of the process.     

A Practical Approach of Developing Mathematical Model for All Speed Governors

The paper introduced a special approach for diesel‘s all-speed-governor modeling, which, in some cases,could solve the knotty problem frequently met in computer simulation of diesel propulsion system or diesel generating set. Suppose that it is hard to get a control-oriented governor mathematical model when the general approaches, the analytical approach or the experimental approach, are applied, and that an open-loop step response of the diesel engine and its system is available by means of computer simulation, the critical three parameters of a governor mathematical model, the proportional gain Kp, integral time constant Ki, and derivative time constant Kd, can be determined by use of PID tuning method which are widely applied in industrial process control. This paper discussed the train of thought of the approach, precondition, procedure, several modifications of the classical PID model, and some points for attention. A couple of case studies were given to demonstrate the effectiveness of this approach.     

基于支持向量机的桁架桥可靠度评估

针对桁架桥结构极限状态方程一般难以显式表达的特点,提出基于支持向量机的桁架桥可靠度评估方法。通过抽样,采用桁架桥有限元计算,利用支持向量机的非线性映射和泛化能力,建立随机变量与结构响应之间的函数关系,模拟结构极限状态方程,采用优化算法计算桁架桥可靠指标。研究表明:该方法对于评估桁架桥可靠度具有较高的计算精度,但随车辆荷载随机变量的离散性增加,桁架桥的失效概率显著增大。     

面向地震应急的救援路径规划模型

地震灾害场景下,面向应急的救援路径规划需要兼顾救援效率和交通抢通对救援的影响,以支撑有限交通资源的高效利用,避免交通拥堵或瘫痪耽误应急救援行动.通过定义面向应急需求的交通网络、交通路线的通行成本和交通线的通过性等,对救援与抢通路径规划问题进行了描述;将最优救援路径和最优交通抢通方案作为该问题的约束条件,基于双层优化方法建立了双层路径规划模型以实现集成优化并构建了模型求解方法.经案例仿真分析,本文提出的救援路径规划模型可以生成准确、高效的应急救援与交通抢通集成方案,可以为具有针对性的交通管制措施的拟定提供科学依据,助力地震应急救援行动的顺利实施.