异构无线融合网络统一接入认证研究

不同网络同时维护多套认证设施会大幅降低异构融合网络的接入效率,多套认证机制中的短板效应也会降低融合网络中的安全性能。为此,提出基于用户、位置、寻址的信息分离技术,从移动通信系统对安全的需求出发,分析并借鉴3G网络认证与密钥分配协议,在异构无线网络环境中建立基于统一用户标识的的认证方案。仿真测试结果表明,该方案实现了异构网络和移动终端的统一接入及安全 认证。     

An observer-based approach for the projection onto a 2d-curve under movement

Standard path control laws of autonomous vehicles use the shortest distance between the vehicle’s position and the path as a control error. In order to determine this distance, the projection point onto the path needs to be determined continuously. This requires fast algorithms that feature high numerical reliability in the field of vehicle application.This paper presents two different observer-based approaches for the projection problem. The identity observer reconstructs all states of interest for path control. The second one, a reduced observer, only possesses the curve parameter as a state and calculates the other values by algebraic formulas. Both algorithms consider the continuous movement of the vehicle, the run of the curve, and work without any approximation of the curve. Furthermore, they are applicable for arbitrary parameterized smooth curves, guarantee the required numerical stability, have short calculating time, and show good statistical properties. The performance is shown in several simulations as well as under real conditions.     

发动机嵌入式传感器自主供电装置

通过热电形式,发动机内部的废热可以为嵌入式传感器提供工作所需要的电能。根据温差发电原理设计了一种能够利用发动机内部存在的温度差为嵌入式传感器供电的装置。它由集热板、隔热层、散热装置以及相应的电源管理电路组成。在负载与发电器件内阻匹配和最低温度差为10℃的条件下,电源管理电路能够将发电器件输出的0.52 V电压转化为5.06 V、4.57 mA的稳定输出。建立了实验模型,且通过实验进行了性能验证。     

非线性积分滑模控制方法

针对一类不确定非线性系统的滑模控制,提出了一类具有"小误差放大,大误差饱和"功能的光滑非线性饱和函数来改进传统的积分滑模控制,以形成非线性积分滑模控制.在保持传统积分滑模控制跟踪精度的同时获得更好的暂态性能.应用Lyapunov稳定性理论和LaSalle不变性原理证明了对最终常值干扰可以完全抑制.考虑控制受限时,所设计...     

一类不确定非线性系统的全局鲁棒有限时间镇定

对一类不确定非线性系统提出了一种连续的全局鲁棒有限时间控制律．首先,针对标称系统设计出了一种状态反馈控制律,应用Lyapunov直接稳定性理论和Lasalle不变性原理证明了闭环标称系统的全局渐近稳定性,同时具有负的齐次度;其次,引入辅助变量和采用有限时间收敛的二阶滑模Super—twisting算法,设计出了对不确定性和干扰进行抑制的补偿控制项,并根据有限时间Lyapunov函数给出了补偿控制项参数的取值范围;最后,综合得到一种连续的使实际闭环系统有限时间收敛到平衡点的鲁棒镇定控制律．仿真结果表明了所提控制律的有效性．     

模糊相关机会规划的蚁群优化算法及收敛性分析

模糊相关机会规划(Fuzzy dependent-chance programming, FDCP)因其非线性、非凸性及模糊性,对经典的优化理论提出了极大的挑战. 本文为解决复杂的模糊相关机会规划问题设计了一种基于模糊模拟的蚁群优化算法, 证明了该算法的收敛性,并通过估算期望收敛时间以分析蚁群优化算法的收敛速度. 数值案例研究验证了该算法的有效性、稳定性及准确性.     

Asynchronous double-precision windows based unmanned aerial vehicle real-time path planning

A real-time path planning approach based on asynchronous double-precision windows is proposed for unmanned aerial vehicles (UAVs). In this proposed method, cursory paths and elaborate paths are planned respectively in the global and local windows. Specifically, global cursory path planner and local elaborate path planner are integrated by rolling two windows on different frequencies with different modes. Simulation results demonstrate that the proposed approach is effective for realizing a balance between t...     

Hiding message delivery latency using Direct-to-Cache-Transfer techniques in message passing environments

Communication overhead is the key obstacle to reaching hardware performance limits. The majority is associated with software overhead, a significant portion of which is attributed to message copying. To reduce this copying overhead, we have devised techniques that do not require to copy a received message in order for it to be bound to its final destination. Rather, a late-binding mechanism, which involves address translation and a dedicated cache, facilitates fast access to received messages by the consuming process/thread.We have introduced two policies namely Direct to Cache Transfer (DTCT) and lazy DTCT that determine whether a message after it is bound needs to be transferred into the data cache. We have studied the proposed methods in simulation and have shown their effectiveness in reducing access times to message payloads by the consuming process.     

A new autonomous celestial navigation method for the lunar rover

A secure and autonomous navigation system is needed for the lunar rover in future lunar missions in case of emergencies. Celestial navigation is a very attractive solution for long distance navigation on the Moon without the need of ground navigation aids. It only uses star altitudes, which are measured by a high accuracy star sensor and inertial measurement unit (IMU) to estimate the position of the rover. The navigational accuracy of this method depends largely on the accuracy of measurements, so the measurement errors have a great impact on the navigational performance. A new autonomous celestial navigation method for the lunar rover is presented in this paper, which uses the augmented state unscented particle filter (ASUPF) to deal with the systematic error and random error in the measurements. The validity and feasibility of this new method is tested and examined by the hardware-in-loop test. A position estimation error within 60 m is obtained. Compared to the conventional method, this method shows better navigation performance and higher adaptability to these measurement errors.     

Fuzzy axiomatic design extension for managing model selection paradigm in decision science

The model selection paradigm is one of the focused themes within decision science. This paper addresses the consistent solution of model selection issue on the basis of the fuzzy axiomatic design (FAD) methodology. Moreover, the developed FAD–based model selection interface (FAD–MSI) is performed over the critical ship management processes in order to assign suitable (multiple criteria decision-making) MCDM techniques even if commonly utilized hybrid approaches. The outcomes of this study encourage the maritime practitioners for the further researches towards analytical modelling of ship management processes.