Some attacks against vehicles' passive entry security systems and their solutions

Recently, several companies have introduced passive entry systems for automotive applications. These systems are intended to increase user comfort by eliminating the requirement that the user has to reach for the customer identification device (CID), a credit card like tool, to gain access to the vehicle compartment. While this extra level of comfort is a desirable feature, especially in luxury vehicles, it introduces several key attacks against the system. This paper describes several techniques of potential attacks against the passive entry system and proposes solutions to protect the vehicle from such attacks.     

5G网络安全风险研究

基于5G网络架构逐层对5G网络存在的安全风险进行梳理与分析,总结出四大安全风险点,即用户标识的安全性、数据的机密性与完整性、终端的真实性以及网络功能的可用性,并提出对策与建议。     

Electrical systems for hybrid vehicles

This paper is a digest of the electrical system section of a report [8] on the feasibility of using a hybrid heat engine/electrical propulsion system as a means of reducing exhaust emissions from street-operated vehicles. The electrical system is composed of an electric traction motor, a generator, control system, and batteries. Batteries are not covered in this paper, but the remainder of the items will be treated here. First, the electrical system parameters or characteristics that have the greatest impact on the total system are considered; next, details of the advantages and disadvantages of various approaches are summarized; and, finally, development efforts are recommended.     

Window designs for DFT-based multicarrier systems

We consider window designs for discrete Fourier transform (DFT) based multicarrier transceivers without using extra cyclic prefix. As in previous works of window designs for DFT-based transceivers, a postprocessing matrix that is generally channel dependent, is needed to have a zero-forcing receiver. We show that postprocessing is channel independent if and only if the window itself has the cyclic-prefixed property. We design optimal windows with minimum spectral leakage subject to the cyclic-prefixed condition. Moreover, we analyze how postprocessing affects the signal-to-noise ratio (SNR) at the receiver, which is an aspect that is not considered in most of the earlier works. The resulting SNR can be given in a closed form. Join optimization of spectral leakage and SNR are also considered. Furthermore, examples demonstrate that we can have a significant reduction in spectral leakage at the cost of a small SNR loss. In addition to cyclic-prefixed systems, window designs for zero-padded DFT-based transceivers are considered. For the zero-padded transceivers, windows that minimize spectral leakage can also be designed.     

复杂网络攻击建模仿真与安全评估方法

互联网是复杂网络中重要的分支,其很多的性质、功能、特性都和复杂网络的性质相关。利用复杂网络的方式建模并利用MATLAB工具,对互联网的网络攻击开展仿真研究,是研究互联网安全特性的很好切入点。基于经典的加权无标度网络模型对复杂网络攻击,本研究选定复杂网络中鲁棒性及网络效率测度来评估网络的安全性,研究和分析了网络在不同的网络环境和攻击模式下的安全性。     

Advanced electronic control systems for electric vehicles

The characteristics and relative advantages of several types of electric vehicle control systems are discussed. An advanced electronic control system for a separately excited dc motor is described. Performance characteristics of an electric vehicle using this control are discussed and recommendations for future systems are given.     

Comparison of contact designs for improved stability of broad areasemiconductor lasers

Patterned electrode designs are used to control optical mode shape in high-power semiconductor lasers by localizing current injection. In this letter, we present comparison of current density profiles in the active layer achieved by different contact designs. Single-voltage digitated contact, distributed regular and random Gaussian contact configurations are studied using numerical solutions of semiconductor device equations that govern electrostatic potential and carrier concentrations in three spatial dimensions. The results of our calculations indicate that lateral current profile is influenced by the contact shape in the transverse direction and the thickness of the junction on the contact side     

Optimal authentication systems and combinatorial designs

In 1982, G.J. Simmons introduced a mathematical model of authentication theory. Recently, E.F. Brickell (1984) and D.R. Stinson (1988) have shown some combinatorial constructions for optimal authentication systems. In the present work, game-theoretical models are proposed for authentication systems that have multilevel costs on sources, and lower bounds of the game values are obtained. Some constructions of the optimal authentication systems that attain the bounds are shown     

智能电网信息安全现状分析及防护建议

在分析智能电网信息安全现状与风险的基础上,重点分析了身份认证、入侵检测、访问控制等智能电网信息安全关键技术的特点,结合电网信息安全风险分析与等级保护的基本要求,从数字水印、指纹识别、多网融合以及安全管理等角度提出了相应的信息安全防护建议,以增强智能电网中视频监控、身份认证、安全接入等环节的信息安全水平,提高智能电网信息安全防护与自主可控能力,确保智能电网业务系统的安稳运行,保障业务数据的安全。     

Considerations in the design of drive systems for on-the-road electric vehicles

The energy and power requirements of a class of on-the-road electric vehicles are developed, and acceleration and speed characteristics of such vehicles in urban traffic are discussed. Curves of average speed under different conditions of traffic are presented, as are curves of average power required during acceleration, average power required during cruising, and peak power required. A dc drive system for propulsion of such a vehicle and an ac drive system appropriate for such an application are described. The two kinds of system are then compared, on an economic as well as a technical basis. A procedure for designing an electric vehicle is outlined, pertinent fields in which research and development are needed are listed, and a reference list on electric vehicles is included.     

Taxonomies of attacks and vulnerabilities in computer systems

Security assessment of a system is a difficult problem. Most of the current efforts in security assessment involve searching for known vulnerabilities. Finding unknown vulnerabilities still largely remains a subjective process. The process can be improved by understanding the characteristics and nature of known vulnerabilities. The knowledge thus gained can be organized into a suitable taxonomy, which can then be used as a framework for systematically examining new systems for similar but as yet unknown vulnerabilities. There have been many attempts at producing such taxonomies. This article provides a comprehensive survey of the important work done on developing taxonomies of attacks and vulnerabilities in computer systems. This survey covers work done in security related taxonomies from 1974 until 2006. Apart from providing a state-of-the-art survey of taxonomies, we also analyze their effectiveness for use in a security assessment process. Finally, we summarize the important properties of various taxonomies to provide a framework for organizing information about known attacks and vulnerabilities into a taxonomy that would benefit the security assessment process.     

汽车内部噪声智能控制系统的设计

噪声主动控制基本思想是由德国物理学家Paul Lueg于1936年发明“电子消声器”时首次提出的。噪声主动控制技术相对传统的被动控制,具有对中、低频段噪声控制效果明显、系统轻巧、实时性强等优点,具有潜在的工程应用价值。     

A partitioning algorithm for technoiogy-mapped designs onsingle-chip emulation systems

Reconfigurable single-chip emulation systems were proposed as an alternative to multichip emulation systems. Because they cannot be emulated on a single chip at once, large designs are sliced into partitions that are downloaded and executed sequentially on the same reconfigurable emulation chip. In this paper, we address the problem of partitioning a design on a reconfigurable single-chip emulator under resource constraints. First, we extract an acyclic flow graph of the design to be emulated. Then, we model the problem as an integer linear programming problem (IP) based on the acyclic flow graph of the design where the structure of the assignment and precedence constraints produce a tight formulation. To partition a design, our algorithm uses two distinct steps with different objectives. In the first step, we minimize the number of cycles needed to schedule every look-up table (LUT) in the circuit. Then flip-flops (FFs) are inserted into the appropriate cycles of the schedule in the second step. Experiments are conducted on small- and medium-size circuits from the MCNC Partitioning93 benchmark suite. The obtained results show that our algorithm produces optimal partitioning schedules     

改进的Floyd算法在套牌车辨别中的应用

针对套牌车辨别中用传统Floyd算法计算最短路径距离存在效率低和速度慢等问题,文中提出了一种改进的Floyd算法,减少了矩阵迭代过程中任意两点之间的最短路径计算量,提高了算法效率。在MATLAB中用同一矩阵对改进前后的Floyd算法进行仿真和比较,结果表明,改进后的算法在效率上高于传统算法。运用某市交通数据集辨别套牌车时,改进的Floyd算法效率比传统Floyd算法的效率提升了近30%,说明了改进的Floyd算法的高效性和实用性。     

基层社区安全的计算机网络入侵检测改进

改进了异常点检测算法的复杂度和收敛速度慢的缺陷,采用加入动量项的改进BP神经网络算法,建立了算法的理论模型和学习过程。对随机抽样的145条记录测试试验中得到:算法大大缩短了训练时间,提高了训练速度,并且准确率也取得了令人比较满意的效果。算法应用实验表明BP具备一定的数据特征筛选的能力,并且能很好地实现异常点区分。上述结果表明改进的BP算法检测对数据集合分类具有可行性,设计成果对于社区安全技术的发展有着明显实际意义。     

Defense against Sybil attacks and authentication for anonymous location-based routing in MANET

In MANET, providing authentication and security to location-based routing is a big task. To overcome this problem, in this paper, we proposed a defense against Sybil attacks and authentication for anonymous location-based routing in MANET. Each random forwarder has a table of RSS values estimated from the previous message exchanges across a zone to detect the Sybil attack. The difference in RSS values of two neighboring nodes is estimated based on which the node’s arrival angle into the zone is detected. Depending on the arrival angle, the nodes can be categorized as safety zone and caution zone. The messages exchanged between the RFs and senders can be protected by means of group signature. Finally, misrouting packet drop attack is detected and eliminated by using ant colony optimization technique. By simulation results, we show the proposed technique reduces the packet drop due to attacks, thereby increasing the delivery ratio.     

改进的网络控制系统安全保障技术方案

安全可靠性是网络控制系统所面临的主要问题之一。本文针对该问题,设计了一种新的网络控制方案。该方案利用工业现场主控台的网络隔离及内核网卡NDIS中间层过滤技术,实现控制系统的网络隐蔽保护。实验结果表明,这不仅减轻了控制器的通讯负担,提高了系统的控制实时性,而且有力保障了整个系统的安全和可靠性。