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1.
针对Web遭受跨站脚本攻击越来越严重的问题,设计了一个基于指令集随机化的服务器端XSS检测和防御模型,并在PhpBB网络论坛系统中进行了实现,通过对实验结果的分析可知,本系统可以很好地检测和防御反射型XSS攻击和存储型XSS攻击,同时能检测和防御因网络或操作系统层漏洞导致的网页篡改和网页挂马等恶意攻击行为。  相似文献   

2.
Web程序通常在页面中嵌入使用JavaScrip脚本来实现检测动态客户端行为。这些脚本在用户浏览器的上下文中被执行。为了防范恶意的JavaScript脚本,浏览器可以使用一套沙盒机制,使脚本只能访问到自己所在网站域的资源。如果用户被诱骗至一个中间的、受信任的网站,然后从该网站下载恶意脚本,那么此套安全机制就失效了。文章呈现了一套Web邮件跨站代码检测系统模型,该模型能满足高效率、优性能下的完整代码测试需求。根据设计需求,文章实现了Web邮件跨站脚本检测系统。最后,对系统的测试结果表明：系统具有一定的可行性与实用性。  相似文献   

3.
首先简要地介绍了虚拟仪器的概念及特点,然后讲述了虚拟仪器与Internet相结合构建网络化虚拟仪器的巨大应用前景.随后阐述了在进行虚拟仪器网络化的过程中需要用到的开发工具和技术,着重讲解了美国NI公司的DataSocket技术在进行虚拟仪器网络化中的优势.通过一个实例具体讲解了如何使用DataSocket技术进行虚拟仪器的Web页面构建.另外还涉及包括构建ActiveX控件、编写HTML文件等内容.  相似文献   

4.
为产生伪随机数字混沌序列,提出了一种新的混沌系统数字化实现方法,该方法采用HTML5技术实现连续混沌系统的离散和迭代运算;基于数字混沌序列和线性插值算法实现了混沌吸引子相图、时间序列的绘制。该方法具有跨平台使用特性、本地储存特性和渲染模式,为把混沌技术的应用植入浏览器提供了可能,该方法可应用于多平台共享的混沌信息加密、混沌演示、混沌性能测试等领域。  相似文献   

5.
    
Site diversity is an effective rain attenuation mitigation technique, especially in the tropical region where high rainfall rates are common. According to our previous study, site diversity gain is found to be dependent on the site separation distance and path elevation angle while it is independent of signal frequency, baseline angle and polarization angle. Therefore, using 28 months of radar data, a simple site diversity gain prediction model is proposed. The proposed model is compared with the existing ITU‐R models. The seasonal wind direction, another factor that might affect the site diversity gain prediction model, is shown to have negligible effect on site diversity gain. Triple‐site diversity is also investigated, and although it is found to provide gain improvement over dual‐site diversity, this gain improvement is too little to justify for the cost of setting up an additional site. This study is useful for the implementation of site diversity as a rain attenuation mitigation technique in the tropical region. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

6.
    
Efficient channel selection is essential in 802.11 mesh deployments, for minimising contention and interference among co‐channel devices and thereby supporting a plurality of quality of service (QoS)‐sensitive applications. A few protocols have been proposed for frequency allocation in such networks; however, they do not address the problem end‐to‐end. In this paper, we present a general formulation of the channel selection problem, taking into account the performance of both mesh access and mesh backhaul. Moreover, we propose a routing‐aware channel selection protocol for wireless mesh networks (ARACHNE). ARACHNE is distributed in nature and motivated by our measurements on a wireless testbed. The main novelty of our protocol comes from adopting a metric that captures the end‐to‐end link loads across different routes in the network. ARACHNE prioritises the assignment of low‐interference channels to links that (i) need to serve high‐load aggregate traffic and/or (ii) already suffer significant levels of contention and interference. Our protocol takes into account the number of potential interfaces (radios) per device and allocates these interfaces in a manner that efficiently utilises the available channel capacity. We evaluate ARACHNE through extensive, trace‐driven simulations, and we show the approaches to the optimal channel selection. We observe that our protocol improves the total network throughput, as compared to three other representative channel allocation approaches in literature. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

7.
    
Na‐ion batteries have experienced rapid development over the past decade and received significant attention from the academic and industrial communities. Although a large amount of effort has been made on material innovations, accessible design strategies on peculiar structural chemistry remain elusive. An approach to in situ construction of new Na‐based cathode materials by substitution in alkali sites is proposed to realize long‐term cycling stability and high‐energy density in low‐cost Na‐ion cathodes. A new compound, [K0.444(1)Na1.414(1)][Mn3/4Fe5/4](CN)6, is obtained through a rational control of K+ content from electrochemical reaction. Results demonstrate that the remaining K+ (≈0.444 mol per unit) in the host matrix can stabilize the intrinsic K‐based structure during reversible Na+ extraction/insertion process without the structural evolution to the Na‐based structure after cycles. Thereby, the as‐prepared cathode shows the remarkably enhanced structural stability with the capacity retention of >78% after 1800 cycles, and a higher average operation voltage of ≈3.65 V versus Na+/Na, directly contrasting the non‐alkali‐site‐substitution cathode materials. This provides new insights into alkali‐site‐substitution constructing advanced Na‐ion cathode materials.  相似文献   

8.
    
We propose an opportunistic cross‐layer architecture for adaptive support of Voice over IP in multi‐hop wireless LANs. As opposed to providing high call quality, we target emergencies where it is important to communicate, even if at low quality, no matter the harshness of the network conditions. With the importance of delay on voice quality in mind, we select adaptation parameters that control the ratio of real‐time traffic load to available bandwidth. This is achieved in two ways: minimizing the load and maximizing the bandwidth. The PHY/MAC interaction improves the use of the spectral resources by opportunistically exploiting rate‐control and packet bursts, while the MAC/application interaction controls the demand per source through voice compression. The objective is to maximize the number of calls admitted that satisfy the end‐to‐end delay budget. The performance of the protocol is studied extensively in the ns‐2 network simulator. Results indicate that call quality degrades as load increases and overlonger paths, and a larger packet size improves performance. For long paths having low‐quality channels, forward error correction, header compression, and relaxing the delay budget of the system are required to maintain call admission and quality. The proposed adaptive protocol achieves high performance improvements over the traditional, non‐adaptive approach. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

9.
This paper presents a fast block‐matching algorithm based on the normalized cross‐correlation, where the elimination order is determined based on the gradient magnitudes of subblocks in the current macroblock. Multilevel Cauchy‐Schwartz inequality is derived to skip unnecessary block‐matching calculations in the proposed algorithm. Also, additional complexity reduction is achieved re‐using the normalized cross correlation values for the spatially neighboring macroblock because the search areas of adjacent macroblocks are overlapped. Simulation results show that the proposed algorithm can improve the speed‐up ratio up to about 3 times in comparison with the existing algorithm.  相似文献   

10.
    
This paper proposed an energy‐aware cross‐layer mobile cloud resource allocation approach. In this paper, a hybrid cloud architecture is adopted for provisioning mobile service to mobile device users, which include nearby local cloud and remote public cloud. The computation‐intensive tasks can be processed by the remote public cloud, while the delay‐sensitive computation can be processed by the nearby local cloud. On the basis of the system context and mobile user preferences, the energy‐aware cross‐layer mobile cloud resource allocation approach can optimize the consumption of cloud resource and system performance. The cooperation and collaboration among local cloud agent, public cloud supplier, and mobile cloud user are regulated through the economic approach. The energy‐aware cross‐layer mobile cloud resource allocation is performed on the local cloud level and the public cloud level, which comprehensively considers the benefits of all participants. The energy‐aware cross‐layer mobile cloud resource allocation algorithm is proposed, which is evaluated in the experiment environment, and comparison results and analysis are discussed.  相似文献   

11.
    
Most CDMA systems serve only finite number of active users. Therefore, using Gaussian approximation to evaluate its performance is inappropriate. In such finite CDMA systems, the selection of spreading codes is of great importance because its performance is very much spreading‐code‐dependent. In this paper, a new algorithm based on multiple variable Bernoulli process is introduced to evaluate bit error rate due to co‐channel interference and thus the capacity of a CDMA system. The algorithm can also be used for large‐sized CDMA systems. The results show that small Kasami and Gold‐like codes offer higher capacity than the others do. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

12.
    
Previous quality‐of‐service (QoS) routing protocols in mobile ad hoc networks (MANETs) determined bandwidth‐satisfied routes for QoS applications. Since the multi‐rate enhancements have been implemented in MANETs, QoS routing protocols should be adapted to exploit them fully. However, existing works suffer from one bandwidth‐violation problem, named the hidden route problem (HRP), which may arise when a new flow is permitted and only the bandwidth consumption of the hosts in the neighborhood of the route is computed. Without considering the bandwidth consumption to ongoing flows is the reason the problem is introduced. This work proposes a routing protocol that can avoid HRP for data rate selection and bandwidth‐satisfied route determination with an efficient cross‐layer design based on the integration of PHY and MAC layers into the network layer. To use bandwidth efficiently, we aim to select the combination of data rates and a route with minimal bandwidth consumption to the network, instead of the strategy adopted in the most previous works by selecting the combination with the shortest total transmission time. Using bandwidth efficiently can increase the number of flows supported by a network. Copyright 2010 John Wiley & Sons, Ltd.  相似文献   

13.
    
Photovoltaic performance of cross‐linkable Ru(2,2′‐bipyridine‐4,4′‐bicarboxylic acid)(4,4′‐bis((4‐vinyl benzyloxy)methyl)‐2,2′‐bipyridine)(NCS)2 (denoted as RuS dye) adsorbing on TiO2 mesoporous film was enhanced by polymerizing with either ionic liquid monomer, 1‐(2‐acryloyloxy‐ethyl)‐3‐methyl‐imidazol‐1‐ium iodide (AMImI), to form RuS‐cross‐AMImI or di‐functional acrylic monomer with ether linkage, triethyleneglycodimethacrylate (TGDMA), to form RuS‐cross‐TGDMA. Their cross‐linking properties were investigated by UV–vis spectroscopy by rinsing with 0.1 N NaOH aqueous solution. The power conversion efficiencies (PCEs) of dye‐sensitized solar cells (DSSCs) with RuS‐cross‐AMImI and RuS‐cross‐TGDMA both reached over 8% under standard global air mass 1.5 full sunlight. The increased PCE for DSSCs with RuS‐cross‐AMImI comparing with cross‐linked RuS was attributed to the I− counterion of AMImI increasing the charge regeneration rate of RuS dye, whereas that with RuS‐cross‐TGDMA was attributed to the Li+ coordination property of TGDMA. The photovoltaic performance of RuS‐cross‐TGDMA was also slightly better than that of RuS‐cross‐AMImI because of higher open‐circuit photovoltage (Voc) and short‐circuit photocurrent (Jsc). Its higher Voc was supported by the Bode plot of impedance under illumination and Nyquist plots at dark, whereas higher Jsc was supported by the incident monochromatic photon‐to‐current conversion efficiency spectra and charge extraction experiments. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

14.
    
Programming language concepts have inspired some networking design decisions. For example, concepts such as object encapsulation and interface invocation have been borrowed, at the time of their adoption, from an already well established object oriented programming paradigm. The authors suggest in this paper that it may be time again to revisit emerging software engineering programming paradigms to learn from them. More specifically, this paper discusses the practical tangling problem, embedded in conventional layer‐coupling (linking) network software design and highlighted by recent research proposals for cross layer design. The adopted solution is based on the aspect‐oriented programming paradigm. We show its programming efficiency, limitations and role in the seamless enforcement of multiple policy scenarios while emphasizing little design changes. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

15.
    
Reproducible low‐voltage bipolar resistive switching is reported in bilayer structures of p‐type SnO films. Specifically, a bilayer homojunction comprising SnOx (oxygen‐rich) and SnOy (oxygen‐deficient) in nanoscale cross‐point (300 × 300 nm2) architecture with self‐compliance effect is demonstrated. By using two layers of SnO film, a good memory performance is obtained as compared to the individual oxide films. The memory devices show resistance ratio of 103 between the high resistance and low resistance states, and this difference can be maintained for up to 180 cycles. The devices also show good retention characteristics, where no significant degradation is observed for more than 103 s. Different charge transport mechanisms are found in both resistance states, depending on the applied voltage range and its polarity. The resistive switching is shown to originate from the oxygen ion migration and subsequent formation/rupture of conducting filaments.  相似文献   

16.
    
In this paper, we propose, verify, and evaluate a method combining cross‐layer method and bandwidth allocation to overcome the difficulty of flow control in a network with large bandwidth delay product. When the bandwidth delay product is large, there are problems with the convergence time, efficiency and stability of bandwidth utilization, and fairness among traffics of different round‐trip time. As a result of examining the conventional methods, we propose a novel method that can be realized as a functional addition to the existing transmission control protocol (TCP) flow control with improvement in utilization efficiency, fairness, stability, and convergence time. The method is compared with TCP Reno, FAST TCP, CUBIC, Explicit Congestion Notification, and eXplicit Control Protocol by simulation, and is confirmed as having good characteristics.  相似文献   

17.
    
Because of the broadcast and overhearing capability of wireless networks, network coding can greatly improve throughput in wireless networks. However, our investigation of existing inter‐session network coding protocols found that the short‐term unfairness that existed in 802.11‐based medium access control (MAC) protocols actually decreases the coding opportunity, which in turn compromises the throughput gain of network coding. To alleviate the negative impact of this unfairness, we propose a coding‐aware cross‐layer heuristic approach to optimize the coordination of network coding and MAC layer protocol, named FairCoding, which can significantly increase coding opportunities for inter‐session network coding through a fair short‐term traffic allocation for different coding flows. Experiment evaluation shows that the proposed mechanism can bring more coding opportunities and improve the total throughput of wireless mesh networks by up to 20%, compared with the coding mechanism, without considering the negative impact of the short‐term unfairness. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

18.
    
In multiwire cables, high‐frequency signals can, and do, propagate not only by direct conduction over a pair of wires the signal was inserted to but also by electromagnetic coupling between adjacent transmission lines formed out of multiple wire pairs, too. Thus, it is useful to be able to measure relevant parameters, dependent of cable geometry and isolation material, that would enable modeling of cross‐talk propagation. In this article, signal propagation between ports of two coupled lines is first theoretically analyzed using z‐parameters. Then, the physical quantities needed for calculation of z‐parameters in systems with electrically long cable sections were defined and measured, and the results were verified against measurements performed on real cables. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

19.
    
In this paper, we consider a cross‐layer design aimed to enhance performance for uplink transmission in an orthogonal frequency division multiple‐access (OFDMA)‐based cellular network with fixed relay stations. Because mobile stations (MSs) spend most of the power on the uplink transmission, power efficiency resource allocation becomes very important to MSs. We develop a cross‐layer optimisation framework for two types of uplink flows (inelastic and elastic flows) that have different quality‐of‐service requirements. For inelastic flows with fixed‐rate requirement, we formulate the cross‐layer optimisation problem as the minimisation of the sum transmission power of MSs under the constraints of flow conservation law, subcarrier assignment, relaying path selection and power allocation. For elastic flows with flexible‐service‐rate requirement, we consider the cross‐layer trade‐off between uplink service rate and power consumption of MSs and pose the optimisation problem as the maximisation of a linear combination of utility (of service rates) and power consumption (of MSs). Different trade‐offs can be achieved by varying the weighting parameters. Dual decomposition and subgradient methods are used to solve the problems optimally with reduced computational complexity. The simulation results show that, through the proposed cross‐layer resource optimisation framework and algorithms, significant benefits of deployment of multiple fixed relays in an OFDMA cellular network can be fully obtained such as reduction in power consumption, increase in service rate and energy savings in the uplink transmission of MSs. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

20.
    
In this paper, we propose a cross‐layer optimized geographic node‐disjoint multipath routing algorithm, that is, two‐phase geographic greedy forwarding plus. To optimize the system as a whole, our algorithm is designed on the basis of multiple layers' interactions, taking into account the following. First is the physical layer, where sensor nodes are developed to scavenge the energy from environment, that is, node rechargeable operation (a kind of idle charging process to nodes). Each node can adjust its transmission power depending on its current energy level (the main object for nodes with energy harvesting is to avoid the routing hole when implementing the routing algorithm). Second is the sleep scheduling layer, where an energy‐balanced sleep scheduling scheme, that is, duty cycle (a kind of node sleep schedule that aims at putting the idle listening nodes in the network into sleep state such that the nodes will be awake only when they are needed), and energy‐consumption‐based connected k‐neighborhood is applied to allow sensor nodes to have enough time to recharge energy, which takes nodes' current energy level as the parameter to dynamically schedule nodes to be active or asleep. Third is the routing layer, in which a forwarding node chooses the next‐hop node based on 2‐hop neighbor information rather than 1‐hop. Performance of two‐phase geographic greedy forwarding plus algorithm is evaluated under three different forwarding policies, to meet different application requirements. Our extensive simulations show that by cross‐layer optimization, more shorter paths are found, resulting in shorter average path length, yet without causing much energy consumption. On top of these, a considerable increase of the network sleep rate is achieved. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

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