The ability of a modified bow-tie dipole antenna, which has an asymmetric-feed structure to operate at UHF-band (470-862 MHz) and dual ISM-band (2.4 GHz and 5.8 GHz) is demonstrated. Experimental results indicate that the VSWR 2:1 bandwidths achieved were 125.7%, 8.2% and 23.6% at 660 MHz, 2.45 GHz and 5.5 GHz. The proposed modified bow-tie dipole exhibits a nearly omni-directional radiation pattern with very easy to fabricate structure, and so is suitable for various commercial wideband applications.

Much recent research concentrates on designing an Intrusion Detection System (IDS) to detect the misbehaviors of the malicious node in MANET with ad-hoc and mobility natures. However, without rapid and appropriate IDS response mechanisms performing follow-up management services, even the best IDS cannot achieve the desired primary goal of the incident response. A competent containment strategy is needed to limit the extent of an attack in the Incident Response Life Cycle. Inspired by the T-cell mechanisms in the human immune system, we propose an efficient MANET IDS response protocol (T-SecAODV) that can rapidly and accurately disseminate alerts of the malicious node attacks to other nodes so as to modify their AODV routing tables to isolate the malicious nodes. Simulations are conducted by the network simulator (Qualnet), and the experiment results indicate that T-SecAODV is able to spread alerts steadily while greatly reduce faulty rumors under simultaneous multiple malicious node attacks.

Free probability theory, which has become a main branch of random matrix theory, is a valuable tool for describing the asymptotic behavior of multiple systems, especially for large matrices. In this paper, using asymptotic free probability theory, a new cooperative scheme for spectrum sensing is proposed, which shows how the asymptotic free behavior of random matrices and the property of Wishart distribution can be used to assist spectrum sensing for cognitive radio. Simulations over Rayleigh fading and AWGN channels demonstrate the proposed scheme has better detection performance than the energy detection techniques and the Maximum-minimum eigenvalue (MME) scheme even for the case of a small sample of observations.

Web application second-order vulnerabilities first inject malicious code into the persistent data stores of the web server and then execute it at later sensitive operations, causing severe impact. Nevertheless, the dynamic features, the complex data propagation, and the inter-state dependencies bring many challenges in discovering such vulnerabilities. To address these challenges, we propose DISOV, a web application property graph (WAPG) based method to discover second-order vulnerabilities. Specifically, DISOV first constructs WAPG to represent data propagation and inter-state dependencies of the web application, which can be further leveraged to find the potential second-order vulnerabilities paths. Then, it leverages fuzz testing to verify the potential vulnerabilities paths. To verify the effectiveness of DISOV, we tested it in 13 popular web applications in real-world and compared with Black Widow, the state-of-the-art web vulnerability scanner. DISOV discovered 43 second-order vulnerabilities, including 23 second-order XSS vulnerabilities, 3 second-order SQL injection vulnerabilities, and 17 second-order RCE vulnerabilities. While Black Widow only discovered 18 second-order XSS vulnerabilities, with none second-order SQL injection vulnerability and second-order RCE vulnerability. In addition, DISOV has found 12 0-day second-order vulnerabilities, demonstrating its effectiveness in practice.

An on-package dual-mode square-loop band pass filter is studied by applying a non-uniform finite difference time domain (NU-FDTD) method. The filter is integrated on a package containing a transceiver, and it is designed to operate in dual-modes, i.e., and , to ensure a good electric performance around the center frequency at 5.25 GHz, which is commonly allocated in wireless local area network (WLAN). This filter is also referred as a dual-mode integrated-circuit package filter (DM-ICPF) based on its operational mode and integration onto an IC-package. The frequency characteristics in terms of the scattering parameters are studied, and the results are validated against the computed results using commercial software, the high frequency structure simulator (HFSS). Results show an excellent agreement between the numerical data, and the proposed DM-ICPF structure can be applied in the area of the highly integrated wireless transceivers.

In this letter, we propose an appealing class of nonbinary quasi-cyclic low-density parity-check (QC-LDPC) cycle codes. The parity-check matrix is carefully designed such that the corresponding generator matrix has some nice properties: 1) systematic, 2) quasi-cyclic, and 3) sparse, which allows a parallel encoding with low complexity. Simulation results show that the performance of the proposed encoding-aware LDPC codes is comparable to that of the progressive-edge-growth (PEG) constructed nonbinary LDPC cycle codes.

Based on Free Probability Theory (FPT), which has become an important branch of Random Matrix Theory (RMT), a new scheme of frequency band sensing for Cognitive Radio (CR) in Direct-Sequence Code-Division Multiple-Access (DS-CDMA) multiuser network is proposed. Unlike previous studies in the field, the new scheme does not require the knowledge of the spreading sequences of users and is related to the behavior of the asymptotic free behavior of random matrices. Simulation results show that the asymptotic claims hold true even for a small number of observations (which makes it convenient for time-varying topologies) outperforming classical energy detection scheme and another scheme based on random matrix theory.

Quasi-cyclic (QC) low-density parity-check (LDPC) codes have several appealing properties regarding decoding, storage requirements and encoding aspects. In this paper, we focus on the QC LDPC codes over GF(q) whose parity-check matrices have fixed column weight j = 2. By investigating two subgraphs in the Tanner graphs of the corresponding base matrices, we derive two upper bounds on the minimum Hamming distance for this class of codes. In addition, a method is proposed to construct QC LDPC codes over GF(q), which have good Hamming distance distributions. Simulations show that our designed codes have good performance.

Particle filter algorithm is an important algorithm in the field of target tracking. however, this algorithm faces the problem of sample impoverishment which is caused by the introduction of re-sampling and easily affected by illumination variation. This problem seriously affects the tracking performance of a particle filter algorithm. To solve this problem, we introduce a particle filter target tracking algorithm based on a dynamic niche genetic algorithm. The application of this dynamic niche genetic algorithm to re-sampling ensures particle diversity and dynamically fuses the color and profile features of the target in order to increase the algorithm accuracy under the illumination variation. According to the test results, the proposed algorithm accurately tracks the target, significantly increases the number of particles, enhances the particle diversity, and exhibits better robustness and better accuracy.

With quick topology changes due to mobile node movement or signal fading in MANET environments, conventional routing restoration processes are costly to implement and may incur high flooding of network traffic overhead and long routing path latency. Adopting the traditional shortest path tree (SPT) recomputation and restoration schemes used in Internet routing protocols will not work effectively for MANET. An object of the next generation SPT restoration system is to provide a cost-effective solution using an adaptive learning control system, wherein the SPT restoration engine is able to skip over the heavy SPT computation. We proposed a novel SPT restoration scheme, called Cognitive Shortest Path Tree Restoration (CSPTR). CSPTR is designed based on the Network Simplex Method (NSM) and Sensitivity Analysis (SA) techniques to provide a comprehensive and low-cost link failure healing process. NSM is used to derive the shortest paths for each node, while the use of SA can greatly reduce the effort of unnecessary recomputation of the SPT when network topology changes. In practice, a SA range table is used to enable the learning capability of CSPTR. The performance of computing and communication overheads are compared with other two well-known schemes, such as Dijstra's algorithm and incremental OSPF. Results show that CSPTR can greatly eliminate unnecessary SPT recomputation and reduce large amounts of the flooding overheads.