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2.
本文在[1]文的基础上进一步分析了循环码的周期分布的性质,给出了新的计算方法和公式,并且确定了一些熟知的循环码的周期分布。 相似文献
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本文重点分析了现代家居智能化系统的需要实现的基本功能,探讨了于Zigbee技术的家居智能控制系统的整个设计思路,从硬软件的角度解析了家居智能控制系统具体设计细节等。 相似文献
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对PVK在电场调制下的光致发光现象进行了研究,发现在高场下光致发光强度会减弱,且存在一个阈值,在阈值以下发光强度随电增加缓慢减弱,在域值以上则在出发光强度迅速减弱的趋势。 相似文献
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软件测试是确保软件质量的可靠手段,是软件开发过程中必不可少的重要环节。随着软件项目中各类干系人对软件质量的要求不断提高,软件测试作为保证软件质量的主要途径之一,其重要性越来越受重视。随着软件复杂性提高,软件测试的复杂性也不断提高,测试成本不断增加,同时软件复用技术也在不断发展,软件测试成本的提高和软件复用技术的发展,促使了软件测试复用技术的不断发展。测试复用技术在软件领域得到了广泛的应用,在某些行业软件中得到了很好的应用,比如证券行业。 相似文献
7.
细胞的内质网呈网状遍布于细胞质内,所以也可称之为内质网膜系统。内质网是细胞的内膜系统的重要成分,在蛋白质合成,脂类合成和糖原代谢等方面起着重要作用。研究证明细胞内的许多膜性结构均来源于内质网,因而它在细胞的内膜系统中占有中心地位。内质网的微细结构的观察与研究对了解细胞的正常生理和病理改变具有重要意义。我们对培训的非洲绿猴肾上皮细胞(CV-1),人早幼粒白血病细胞(HL-60)、活检的人体胃粘膜细胞和胃癌细胞以及手术切除的人体结肠细胞和结肠癌细胞等数种细胞的内质网,应用电镜技术和光镜技术进行了观察与分析。 相似文献
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事实上,很多物品的灵感来自于自然,专业一些的说法叫仿生。不过这种黎法似乎显得太过严肃和学术,对于那些生活中和身边的物品,称它们是向自然讨教得来的一种“比喻”更形象。 相似文献
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现场总线以数字信号取代模拟信号,在3C技术即计算机(Computer)、控制(Control)、通信(Communication)的基础上,大量现场检测与控制的信息就地采集、就地处理、就地使用, 相似文献
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随着PC技术的发展,硬盘的容量和性能越来越高了,但是,该买什么样的硬盘,这是很多囊中羞涩的用户所困惑的,下面笔者就结合自己的经验跟大家介绍一下,如何选择一块合适自己的硬盘. 相似文献
11.
如今,无线传感器网络是一种新的和有前途的下一代实时无线监控应用的解决方案。如果在考虑部署传感器网络之前没有适当的安全考虑,可以成为一个威胁。但是,如果有任何安全漏洞,即可能向攻击者敞开了大门并且危害应用。因此,用户身份验证的核心要求之一,以防止未经授权的无线传感器网络的数据访问用户。在这方面提出一个有效的双重身份验证的无线传感器网络,它是基于密码和智能卡(双重)。计划提供了相互认证,使用户能够选择和频繁地改变自己密码。再者,通过合理计算成本,提供强大的保护防止不同类型的攻击。 相似文献
12.
Since wireless sensor networks (WSN) are often deployed in an unattended environment and sensor nodes are equipped with limited computing power modules, user authentication is a critical issue when a user wants to access data from sensor nodes. Recently, M.L. Das proposed a two-factor user authentication scheme in WSN and claimed that his scheme is secure against different kinds of attack. Later, Khan and Alghathbar (K-A) pointed out that Das’ scheme has some security pitfalls and showed several improvements to overcome these weaknesses. However, we demonstrate that in the K-A-scheme, there is no provision of non-repudiation, it is susceptible to the attack due to a lost smart card, and mutual authentication between the user and the GW-node does not attained. Moreover, the GW-node cannot prove that the first message comes from the user. To overcome these security weaknesses of the K-A-scheme, we propose security patches and prove our scheme. 相似文献
13.
针对无线传感器网络(WSN)用户远程安全认证问题,分析现有方案的不足,提出一种新颖的基于智能卡的WSN远程用户认证方案。通过用户、网关节点和传感器节点之间的相互认证来验证用户和节点的合法性,并结合动态身份标识来抵抗假冒攻击、智能卡被盗攻击、服务拒绝攻击、字典攻击和重放攻击。同时对用户信息进行匿名保护,且用户能够任意修改密码。性能比较结果表明,该方案具有较高的安全性能,且具有较小的计算开销。 相似文献
14.
In wireless sensor networks (WSNs), there are many critical applications (for example, healthcare, vehicle tracking, and battlefield), where the online streaming data generated from different sensor nodes need to be analyzed with respect to quick control decisions. However, as the data generated by these sensor nodes usually flow through open channel, so there are higher chances of various types of attacks either on the nodes or on to the data captured by these nodes. In this paper, we aim to design a new elliptic curve cryptography–based user authenticated key agreement protocol in a hierarchical WSN so that a legal user can only access the streaming data from generated from different sensor nodes. The proposed scheme is based upon 3‐factor authentication, as it applies smart card, password, and personal biometrics of a user (for ticket generation). The proposed scheme maintains low computation cost for resource‐constrained sensor nodes, as it uses efficient 1‐way cryptographic hash function and bitwise exclusive‐OR operations for secure key establishment between different sensor nodes. The security analysis using the broadly accepted Burrows‐Abadi‐Needham logic, formal security verification using the popular simulation tool (automated validation of Internet security protocols and applications), and informal security show that the proposed scheme is resilient against several well‐known attacks needed for a user authentication scheme in WSNs. The comparison of security and functionality requirements, communication and computation costs of the proposed scheme, and other related existing user authentication schemes shows the superior performance of the proposed scheme. 相似文献
15.
The presence of ubiquitous connectivity provided by wireless communications and mobile computing has changed the way humans interact with information. At the same time, it has made communication security and privacy a hot-button issue. In this article we address the security and privacy concerns in wireless access networks. We first discuss the general cryptographic means to design privacy-preserving security protocols, where the dilemma of attaining both security and privacy goals, especially user accountability vs. user privacy, is highlighted. We then present a novel authentication framework that integrates a new key management scheme based on the principle of separation of powers and an adapted construction of Boneh and Shacham's group signature scheme, as an enhanced resort to simultaneously achieve security, privacy, and accountability in wireless access networks. 相似文献
16.
Wireless sensor networks (WSNs) are used for many real‐time applications. User authentication is an important security service for WSNs to ensure only legitimate users can access the sensor data within the network. In 2012, Yoo and others proposed a security‐performance‐balanced user authentication scheme for WSNs, which is an enhancement of existing schemes. In this paper, we show that Yoo and others' scheme has security flaws, and it is not efficient for real WSNs. In addition, this paper proposes a new strong authentication scheme with user privacy for WSNs. The proposed scheme not only achieves end‐party mutual authentication (that is, between the user and the sensor node) but also establishes a dynamic session key. The proposed scheme preserves the security features of Yoo and others' scheme and other existing schemes and provides more practical security services. Additionally, the efficiency of the proposed scheme is more appropriate for real‐world WSNs applications. 相似文献
17.
In global mobility networks, anonymous user authentication is an essential task for enabling roaming service. In a recent paper, Jiang et al. proposed a smart card based anonymous user authentication scheme for roaming service in global mobility networks. This scheme can protect user privacy and is believed to have many abilities to resist a range of network attacks, even if the secret information stored in the smart card is compromised. In this paper, we analyze the security of Jiang et al.’s scheme, and show that the scheme is in fact insecure against the stolen-verifier attack and replay attack. Then, we also propose a new smart card based anonymous user authentication scheme for roaming service. Compared with the existing schemes, our protocol uses a different user authentication mechanism, which does not require the home agent to share a static secret key with the foreign agent, and hence, it is more practical and realistic. We show that our proposed scheme can provide stronger security than previous protocols. 相似文献
18.
The Internet of Things (IoT) is one of the most up-to-date and newest technologies that allows remote control of heterogeneous networks and has a good outlook for industrial applications. Wireless sensor networks (or in brief WSNs) have a key role on the Internet of industrial objects. Due to the limited resources of the sensor nodes, designing a balanced authentication scheme to provide security in reasonable performance in wireless sensor networks is a major challenge in these applications. So far, several security schemes have been presented in this context, but unfortunately, none of these schemes have provided desired security in reasonable cost. In 2017, Khemissa et al. proposed a security protocol for mutual authentication between sensor node and user in WSNs, however, in this paper we show that this protocol is not safe enough in the confrontation of desynchronization, user impersonation and gateway impersonation attacks. The proposed attacks succeed with the probability of one and to be realized only require an execution of the protocol. Given merits of the Khemissa et al.’s protocol, we also improved their protocol in such a way that provides suitable level of security, and also we prove its security using two formal ways, i.e. BAN logic and also the Scyther tool. We also argue informally about the improved protocol’s security. 相似文献
19.
User authentication is a prominent security requirement in wireless sensor networks (WSNs) for accessing the real‐time data from the sensors directly by a legitimate user (external party). Several user authentication schemes are proposed in the literature. However, most of them are either vulnerable to different known attacks or they are inefficient. Recently, Althobaiti et al. presented a biometric‐based user authentication scheme for WSNs. Although their scheme is efficient in computation, in this paper, we first show that their scheme has several security pitfalls such as (i) it is not resilient against node capture attack; (ii) it is insecure against impersonation attack; and (iii) it is insecure against man‐in‐the‐middle attack. We then aim to propose a novel biometric‐based user authentication scheme suitable for WSNs in order to withstand the security pitfalls found in Althobaiti et al. scheme. We show through the rigorous security analysis that our scheme is secure and satisfies the desirable security requirements. Furthermore, the simulation results for the formal security verification using the most widely used and accepted Automated Validation of Internet Security Protocols and Applications tool indicate that our scheme is secure. Our scheme is also efficient compared with existing related schemes. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
20.
In modern, wireless sensor networks (WSNs) stand for the next evolutionary and innovative development step in utilities, industrial, building, home, shipboard, and transportation systems automation. The feature of WSNs is easy to deploy and has wide range of applications. Therefore, in distributed and unattended locations, WSNs are deployed to allow a legitimated user to login to the network and access data. Consequently, the authentication between users and sensor nodes has become one of the important security issues. In 2009, M. L. Das proposed a two-factor authentication for WSNs. Based on one-way hash function and exclusive-OR operation, the scheme is well-suited for resource constrained environments. Later, Khan and Algahathbar pointed out the flaws and vulnerabilities of Das’s scheme and proposed an alternative scheme. However, Vaidya et al. found that both Das’s and Khan–Algahathbar’s schemes are vulnerable to various attacks including stolen smart card attacks. Further, Vaidya et al. proposed an improved two-factor user authentication to overcome the security weakness of both schemes. In this paper, we show that Vaidya et al.’s scheme still exposes to a malicious insider attack that seriously threatens the security of WSNs. Furthermore, we propose an improve scheme that mends those vulnerabilities. 相似文献
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