Showing papers in "Aeu-international Journal of Electronics and Communications in 2011"

Reversible data hiding based on multilevel histogram modification and sequential recovery

Abstract: This paper proposes a reversible data hiding method for natural images. Due to the similarity of neighbor pixels’ values, most differences between pairs of adjacent pixels are equal or close to zero. In this work, a histogram is constructed based on these difference statistics. In the data embedding stage, a multilevel histogram modification mechanism is employed. As more peak points are used for secret bits modulation, the hiding capacity is enhanced compared with those conventional methods based on one or two level histogram modification. Moreover, as the differences concentricity around zero is improved, the distortions on the host image introduced by secret content embedding is mitigated. In the data extraction and image recovery stage, the embedding level instead of the peak points and zero points is used. Accordingly the affiliated information is much smaller than in those methods of the kind. A sequential recovery strategy is exploited for each pixel is reconstructed with the aid of its previously recovered neighbor. Experimental results and comparisons with other methods demonstrate our method's effectiveness and superior performance.

A chaotic system based fragile watermarking scheme for image tamper detection

Abstract: In the past few years, various fragile watermarking techniques have been proposed for image authentication and tamper detection. In this paper, a novel chaos based watermarking scheme for image authentication and tamper detection is proposed. Tamper localization and detection accuracy are two important aspects of the authentication watermarking schemes. Our scheme can detect any modification made to the image and can also indicate the specific locations that have been modified. To improve the security of the proposed scheme two chaotic maps are employed. Since chaotic maps are sensitive to initial values, the corresponding position relation between pixels in the watermarked image and the watermark get disturbed, which helps the watermarking scheme to withstand counterfeiting attacks. Initial values of the chaotic maps are used as secret keys in our scheme. The effectiveness of the proposed scheme is checked through a series of attacks. Experimental results demonstrate that the proposed scheme is not only secure but also achieves superior tamper detection and localization accuracy under different attacks. For instance in copy-and-paste attack and collage attack.

Hybrid watermarking algorithm based on Singular Value Decomposition and Radon transform

Abstract: A hybrid robust digital watermarking algorithm based on finite Radon transform (FRAT) and Singular Value Decomposition (SVD) is proposed and simulated. The Discrete Wavelet Transform (DWT) is popularly used as it possesses properties similar to the human visual system (HVS). We will show that, the watermark embedding procedure comes to get better normalized correlation (NC) factor by modifying singular values. Trade off robustness and transparence of digital watermarking is done by using middle frequencies of HL3 and LH3. Experimental results demonstrate that this method is robust against several attacks such as: noise addition, filtering, histogram equalization, gamma correction, JPEG compression, scaling and rotation.

An information hiding algorithm based on intra-prediction modes and matrix coding for H.264/AVC video stream

Abstract: An information hiding algorithm based on intra-prediction modes and matrix coding is proposed for H.264/AVC video stream. It utilizes the block types and modes of intra-coded blocks to embed watermark. intra- 4 × 4 coded blocks (I4-blocks) are divided into groups and two watermark bits are mapped to every three I4-blocks by matrix coding to map between watermark bit and intra-prediction modes. Since only the mode of an I4-block is changed for every two watermark bits, it can guarantee a high PSNR and slight bitrate increase after watermark embedding. Moreover, embedding position template is utilized to select candidate I4-blocks for watermark embedding, which further enhances the security of watermark information. Experimental results on several test sequences demonstrate that the proposed approach can realize blind extraction with real-time performance.

On cooperative coding for narrow band PLC networks

Abstract: Low-frequency narrowband (LF NB) power line communications (PLC) is an old data-communication concept that has received renewed interest in industry, standardization, and academia for its potential to become an important element of the communication infrastructure supporting Smart Grid applications. In this paper, dedicated to Prof. Johannes Huber on the occasion of his 60th birthday, we review and discuss channel modeling and cooperative coding methods for LF NB PLC systems operating in low-voltage access networks.

Color image compression algorithm based on the DCT transform combined to an adaptive block scanning

Abstract: This paper considers the design of a lossy image compression algorithm dedicated to color still images. After a preprocessing step (mean removing and RGB to YCbCr transformation), the DCT transform is applied and followed by an iterative phase (using the bisection method) including the thresholding, the quantization, dequantization, the inverse DCT, YCbCr to RGB transform and the mean recovering. This is done in order to guarantee that a desired quality (fixed in advance using the well known PSNR metric) is checked. For the aim to obtain the best possible compression ratio CR, the next step is the application of a proposed adaptive scanning providing, for each (n, n) DCT block a corresponding (n×n) vector containing the maximum possible run of zeros at its end. The last step is the application of a modified systematic lossless encoder. The efficiency of the proposed scheme is demonstrated by results, especially, when faced to the method presented in the recently published paper based on the block truncation coding using pattern fitting principle.

CMOS-based current-controlled DDCC and its applications to capacitance multiplier and universal filter

Abstract: This paper presents design of an active building block for analog signal processing, named as current-controlled differential difference current conveyor (CCDDCC). Its parasitic resistances at X-terminal can be controlled by an input bias current. The proposed element is realized in a CMOS technology. It displays usability of the new active element, where the maximum bandwidth of voltage and current followers are around 1 GHz, 100 MHz, respectively. The THD is obtained around 0.8% within 0.6 Vp–p input range. The power dissipation of a CCDDCC at 10 μ A biased current is obtained around 1.35 mW with ± 1.25 V power supplies. In addition, grounded capacitor-based floating capacitance multiplier and current-mode (CM) multiple-input single output (MISO) second-order universal analog filters are included as the applications. For realization of a grounded capacitor-based floating capacitance multiplier, it employs three CCDDCCs and one grounded capacitor without resistor connections. The capacitance can be tuned electronically through the bias current. The filter offers the simultaneous realization five type standard filter responses. The quality factor and the frequency response parameters can be independently tuned. The non-ideal effects of the developed structures are examined. SPICE simulation results of proposed CCDDCC and its applications are also presented.

Selective image encryption in fractional wavelet domain

Abstract: Fractional wavelet domain inherits the virtues of wavelet and fractional domain, to provide improved security. Non-consideration of data significance and emphasising on fractional order for the entire security consumes high computational resources without any proportional effect on the security. This article proposes an efficient selective encryption in fractional wavelet domain that encrypts only significant subbands using a chaotic stream cipher. Relationship between normalized information energy and perceptual information of a subband is utilized to select the significant subbands. Thorough performance and security analysis reflects better perceptual and cryptographic security with less computational time.

KHN-equivalent voltage-mode filters using universal voltage conveyors

Abstract: The analog circuit design is very often focused on the design of frequency filters employing different types of active elements. In this paper we present the universal voltage conveyor that is used for the design of the KHN-equivalent filters working in the voltage-mode. Auxiliary voltage inputs of the active elements are used to reduce the number of floating admittances in the structure. Both proposed structures are easily cascadable since the input and output impedances are in theory infinitely high and zero, respectively. The behavior of the filters has been verified through PSpice simulations and furthermore by experimental measurements.

A reconfigurable and adaptive routing method for fault-tolerant mesh-based networks-on-chip

Abstract: High reliability against undesirable effects is one of the key objectives in the design of on-chip networks. This paper presents a very low cost fault-tolerant routing method to tolerate faulty links and routers in mesh-based Networks-on-Chip. This new algorithm can be dynamically reconfigured to support irregular topologies caused by faulty components in a mesh network. In addition, it is a distributed, adaptive and congestion-aware routing algorithm where only two virtual channels are used for both adaptiveness and fault-tolerance. The proposed routing method has a multi-level fault-tolerance capability and therefore it is capable to tolerate more faulty components in more complicated faulty situations with additional hardware costs. The network performance, fault-tolerance capability and hardware overhead are evaluated through appropriate simulations and syntheses. The experimental results show that the overall reliability of a Network-on-Chip is significantly enhanced against multiple component failures with only a small hardware overhead.

Improving the performance of all-optical switching based on nonlinear photonic Crystal microring resonators

Abstract: Photonic crystal microring resonators are suitable devices for all-optical integrated circuits. Small size of the structure without radiation loss and topology of structure make these microrings more flexible in design. The light intensity can also be localized inside them, which is appropriate for nonlinear state. This localization and slow group velocity of light in photonic crystals lead to enhancement of nonlinearity within nonlinear photonic crystal microring resonators. So they can be used as active devices in all-optical integrated circuits which are under wide range of researches recently. In this paper, the nonlinear photonic crystal microring resonator is introduced and three different structures for all-optical switching based on them are proposed and their performances are simulated. Also the three structures are compared and the optimal structure is demonstrated. Required power for switching of optimal structure is 0.5655 W.

A fast and accurate calibration algorithm for real-time locating systems based on the received signal strength indication

Abstract: With the recent growth of IEEE 802.11 based Wireless Local Area Networks (WLANs), there has been new research attempts to use the WLAN technology for location estimation applications in deep indoor environments where traditional locating algorithms are not effective. The received signal strength indication (RSSI) fingerprinting that uses WLAN infrastructure is a compelling approach due to its fast online tracking capability and to its accurate location estimation. However, the RSSI requires an exhaustive calibration phase to build a fingerprint database. To mitigate the time consuming property of the calibration process, several studies have proposed a number of propagation prediction models that derive the distance of a target object from RSSI values at the expense of lower location accuracy. In this study, we propose a new locating algorithm that combines the calibration procedure with the fingerprint prediction model. Our simulation results show that our new approach not only reduces the calibration time, but it also provides comparable location accuracy to that of the conventional calibration-based locating algorithm.

Component reduced floating +/- L, +/- C and +/- R simulators with grounded passive components

Abstract: In this study, a novel immittance simulator circuit is proposed. The proposed circuit can simulate any one of the floating positive or negative inductor simulator (± L ), positive or negative capacitor simulator (± C ) and positive or negative resistor simulator (± R ). It uses only one current backward transconductance amplifier (CBTA) and two grounded passive components. The proposed simulator can be tuned electronically by changing the transconductance value of the CBTA. Moreover, the circuit does not require any conditions of component matching. It has a good sensitivity performance with respect to the tracking errors and the passive components. The performance of the proposed immittance simulator is demonstrated on the fourth-order voltage- and current-mode band-pass filters by using Pspice simulations based on the 0.25 μm TSMC level-7 CMOS technology parameters.

Compact coplanar waveguide fed ultra wideband antenna with a notch band characteristic

Abstract: A coplanar waveguide (CPW) fed ultra-wideband (UWB) antenna with a notch band characteristic is presented for 2.4 GHz and UWB applications. The bandwidth is broadened by embedding two inverted L-shaped slots in the CPW ground and the notch band is achieved by etching a rectangle slot in the CPW ground. The notched band can be controlled by adjusting the length of the rectangle slot and the two inverted L-shaped slots. Experimental and numerical results show that the proposed antenna with compact size of 28 × 21 mm 2 , has an impedance bandwidth range from 2.38 GHz to 12.0 GHz for voltage standing-wave ratio (VSWR) less than 2, expect the notch band frequency 5.0–6.0 GHz for HIPERLAN/2, IEEE 802.11a (5.1–5.9 GHz) and C-band (4.4–5 GHz) for satellite and military applications.

Simple current-mode analog multiplier, divider, square-rooter and squarer based on CDTAs

Abstract: In this paper, the design of simple analog current-mode multiplier, divider, square-rooter and squarer circuits using only two current differencing transconductance amplifiers (CDTAs) is proposed. With the selection of the applied input currents, the proposed circuit can perform four-quadrant current multiplication, division and current-controlled current amplification, without changing its configuration. Moreover, the current-mode square-rooter and squarer circuits can easily be obtained with the possibility of electronically transfer gain adjustment by slight modification of the proposed configuration. All the proposed circuits are insensitive to ambient temperature variations. Additionally, the CDTA non-ideality effects on the proposed circuits are also investigated and discussed. The performances of the realized circuits are examined by PSPICE simulations.

Criterion for the elimination of overflow oscillations in fixed-point digital filters with saturation arithmetic and external disturbance

Abstract: In this paper, a new criterion for the H ∞ elimination of overflow oscillations in fixed-point digital filters with saturation arithmetic and external disturbance is presented. The criterion not only guarantees exponential stability but also reduces the effect of external disturbance to an H ∞ norm constraint. The criterion takes the form of linear matrix inequality (LMI) and, hence, is computationally tractable. An illustrative example is given to demonstrate the effectiveness of the proposed criterion.

Environmental-adaptive indoor radio path loss model for wireless sensor networks localization

Abstract: In the received signal strength indicator (RSSI) based indoor wireless sensor networks localization system, RSSI measurements are very susceptible to multipath fading, anisotropy of antenna, low supply voltage of node and so on, which will cause the system failure to achieve a high location accuracy. This paper presents an environmental-adaptive path loss model. In the process of localization, the calibrated coefficient LSV of low supply voltage, which can be determined by monitoring the supply voltage of the sender, is used to calibrate ranging errors caused by its low supply voltage. The blind node utilizes the absolute value of RSSI to generate the phase of the corresponding receiver's location so as to determine the correction coefficient of indoor multipath fading Ri. Furthermore, in order to improve the accuracy of RSSI measurements, we also take full consideration of the effect of antenna to accurately determine the corresponding path loss model of the two communication nodes. The proposed path loss model is suitable for the majority of wireless location systems that are on the basis of RSSI-based ranging techniques. Experiment results show that the estimation accuracy and adaptability of the proposed path loss model are significantly higher than that of the traditional one.

An energy-efficient multi-layer MAC (ML-MAC) protocol for wireless sensor networks

Abstract: The efficient use of energy is an important performance target to prolong the lifetime of wireless sensor networks (WSNs). As the idle listening of sensor nodes result in primary energy waste, many typical MAC protocols are designed to save power by placing the radio in the low-power sleep mode. In this paper a new energy-efficient multi-layer MAC (ML-MAC) protocol is proposed for wireless sensor networks. It is designed with two main features: low duty cycle and low number of collisions. Sensor nodes in ML-MAC have a very short listening time which would reduce the energy required to communicate with other nodes. Also, the number of collisions in cases where two or more nodes try to send at the same time is minimized in ML-MAC. This saves the energy required to re-send the corrupted packets. Simulation results show much better performance of the energy consumption compared with the existing MAC protocols.

Reliable routing protocol for Vehicular Ad Hoc Networks

Abstract: A critical issue in Vehicular Ad Hoc Networks (VANETs) is the design of reliable routing protocols that are resistant to frequent path disruptions caused by vehicle motion. Therefore, in this paper we propose a routing protocol to identify more reliable paths by predicting the existence of candidate relay nodes when the link expiration time (LET) passes. If the vehicle cannot identify a candidate relay node (that is, if it realizes that a routing hole occurred on the current link), then the data is rerouted to a different block. Simulation results show that the proposed routing protocol reduces the frequency of route failures and data loss while maintaining low routing overhead.

Distributed power control algorithm for multiple access systems based on Verhulst model

Abstract: In this paper the continuous Verhulst dynamic model is used to synthesize a new distributed power control algorithm (DPCA) for use in direct sequence code division multiple access (DS-CDMA) systems. The Verhulst model was initially designed to describe the population growth of biological species under food and physical space restrictions. The discretization of the corresponding differential equation is accomplished via the Euler numeric integration (ENI) method. Analytical convergence conditions for the proposed DPCA are also established. Several properties of the proposed recursive algorithm, such as Euclidean distance from optimum vector after convergence, convergence speed, normalized mean squared error (NSE), average power consumption per user, performance under dynamics channels, and implementation complexity aspects, are analyzed through simulations. The simulation results are compared with two other DPCAs: the classic algorithm derived by Foschini and Miljanic and the sigmoidal of Uykan and Koivo. Under estimated errors conditions, the proposed DPCA exhibits smaller discrepancy from the optimum power vector solution and better convergence (under fixed and adaptive convergence factor) than the classic and sigmoidal DPCAs.

Single-input three-output electronically tunable universal current-mode filter using current follower transconductance amplifiers

Abstract: In this paper, an electronically tunable universal filter configuration with single input and three outputs (SITO) employing a recently introduced active device namely current follower transconductance amplifier (CFTA) is described. The proposed filter is composed of four CFTAs and two grounded capacitors, and is capable of realizing all the standard functions of the universal filter without requiring any component matching criterions and any extra active components. It exhibits low-input and high-output impedances, which is highly desirable for cascading in current-mode. It also offers the advantage feature of an independent electronic adjustment of the natural angular frequency ( ω o ) and the quality factor ( Q ) by means of tuning the external bias currents. Moreover, a high Q -value filter can be obtained by simply adjusting the appropriate ratio of bias currents. The analysis of active and passive sensitivities is shown to be low. In order to demonstrate the performance of the proposed circuit, PSPICE simulation results are provided.

Two novel very small monopole antennas having frequency band notch function using DGS for UWB application

Abstract: In this article, we describe two novel types of coplanar wave-guide (CPW) fed monopole and an asymmetric coplanar strip (ACS) fed half monopole UWB antennas to cover the ultra-wideband frequency operation. The proposed antennas consist of a hexagonal shaped patch with small volume ( 18.4 × 21.5 × 1 mm 3 ) and ( 11.4 × 21.5 × 1 mm 3 ), respectively. The band-rejection operation achieve at the WLAN (5.15–5.85 GHz) band by adding defected ground structure (DGS) or slit in the ground plane. The antennas are fabricated on FR4 substrate with a relative dielectric constant of 4.4 and thickness of 1 mm which are fed by a 50 Ω line. The antennas are investigated numerically and experimentally for their impedance matching properties, frequency notched characteristics, and radiation performances. The measured frequency response shows an impedance bandwidth of 13 GHz or 130% over 3–16 GHz for VSWR 2 .

Efficient impulse noise detection method with ANFIS for accurate image restoration

Abstract: This paper proposes a novel adaptive neuro-fuzzy inference system (ANFIS) based impulse detection method for the restoration of images corrupted by impulse noise (IN). After the corrupted pixels detected by proposed detector, the Median filtering is performed for only these pixels. The performance of the proposed neuro-fuzzy detector based median filter (NFDMF) is evaluated on different test images and compared with 14 different comparison filters from the literature. Experimental results show that the proposed filter shows better performance than the comparison filters in the cases of being effective in noise suppression and detail preservation, especially when the noise ratio is very high.

Design of low-pass filters using some defected ground structures

Abstract: We present characteristics of seven types of simple and complex defected ground structures (DGS) slot to realize the quasi-lumped inductance. A simple DGS follows the Butterworth type response; whereas a complex DGS has quasi-elliptic response. The response of DGS has strong influence on the performance of a 5-pole Chebyshev type low-pass filter (LPF). We present a systematic design process to realize the LPF using these DGS slots. The 5-pole open square (OS) DGS based LPF of cut-off frequency 2.5 GHz provides best measured performances-transition region bandwidth 0.53 GHz, 20 dB rejection band-width 14.7 GHz, insertion loss 1.29 dB. Theses performances are better than the reported results of the 5-pole DGS based LPF in literature.

A collaborative event detection scheme using fuzzy logic in clustered wireless sensor networks

Abstract: Event detection is a critical issue in wireless sensor networks In this letter, a novel collaborative event detection scheme using fuzzy logic in clustered wireless sensor networks is proposed Unlike previous research in which every sensor node or cluster is treated equally during the decision making process, in this letter we evaluate the credibility of clusters by using fuzzy logic and take them into account when the final decision is made at the fusion center Simulation results show that the proposed scheme can provide better accuracy than conventional approaches

Design of 3.1-10.6GHz ultra-wideband CMOS low noise amplifier with current reuse technique

Abstract: A new low complexity ultra-wideband 3.1–10.6 GHz low noise amplifier (LNA), designed in a chartered 0.18 μm RFCMOS technology, is presented in this paper. The ultra-wideband LNA only consists of two simple amplifiers with an inter-stage inductor connected. The first stage utilizing a resistive current reuse and dual inductive degeneration techniques is used to attain a wideband input matching and low noise figure. A common source amplifier with inductive peaking technique as the second stage achieves high flat gain and wide the −3 dB bandwidth of the overall amplifier simultaneously. The implemented ultra-wideband LNA presents a maximum power gain of 15.6 dB, a high reverse isolation of −45 dB and a good input/output return losses are better than −10 dB in the frequency range of 3.1–10.6 GHz. An excellent noise figure (NF) of 2.8–4.7 dB was obtained in the required band with a power dissipation of 14.1 mW under a supply voltage of 1.5 V. An input-referred third-order intercept point (IIP3) is −7.1 dBm at 6 GHz. The chip area including testing pads is only 0.8 mm × 0.9 mm.

Automatic classification of radar targets with micro-motions using entropy segmentation and time-frequency features

Abstract: Micro-Doppler (mD) signatures have great potential in the radar micro-dynamic target classification. An automatic classification method for radar targets with micro-motions is proposed based on the idea of entropy and feature extraction from the spectrogram. In this method, the measurement of entropy is firstly conducted over the time-frequency distribution associated with the minimum filtering operation, the threshold discrimination and the region focusing to obtain the region of interest corresponding to mD signatures in the original spectrogram. It helps acquire the valid region in the time-frequency domain and reduce the computational burden in the following processing. Next, invariant moments and geometric characteristics of time-frequency distribution of mD signatures are extracted from the segmented spectrogram to construct mD feature vectors. A support vector machine (SVM) with decision-tree architecture is then used for multiclass micro-dynamic target classification from radar echoes. Finally, some experimental tests with simulated mD data are carried out to confirm the effectiveness of the proposed method and evaluate the performance under different conditions of signal-to-noise ratio (SNR), training set and feature vector. In addition, issues related to the improvement of classification performance are also discussed.

Characteristic region based watermark embedding with RST invariance and high capacity

Abstract: This paper presents a novel feature point based image watermarking scheme to achieve high capacity information hiding and generalized watermark robustness. The key idea is to embed a binary watermark image into multi-scale feature point based local characteristic regions in transform domain. Watermark synchronization is first achieved by the characteristic regions, which can be extracted using the scale-invariant feature transform and image normalization. Then the watermark image is embedded in a content-based manner by modifying the wavelet transform coefficients. In the detector, the watermark can be extracted from the distorted image directly. Experimental results on Stirmark benchmark 4.0 show that the proposed scheme can resist both traditional signal processing attacks and geometric attacks. Comparisons also demonstrate the advantages of the scheme.

Efficient and robust fragments-based multiple kernels tracking

Abstract: Representing an object with multiple image fragments or patches for target tracking in a video has proved to be able to maintain the spatial information. The major challenges in visual tracking are effectiveness and robustness. In this paper, we propose an efficient and robust fragments-based multiple kernels tracking algorithm. Fusing the log-likelihood ratio image and morphological operation divides the object into some fragments, which can maintain the spatial information. By assigning each fragment to different weight, more robust target and candidate models are built. Applying adaptive scale selection and updating schema for the target model and the weighting factors of each fragment can improve tracking robustness. Upon these advantages, the novel tracking algorithm can provide more accurate performance and can be directly extended to a multiple object tracking system.

Second-order statistics of SC macrodiversity system operating over Gamma shadowed Nakagami-m fading channels

Abstract: This paper derives the second-order statistics of SC (selection combining) macrodiversity operating over the Gamma shadowed Nakagami- m fading channels. Macrodiversity system of SC type consists of two microdiversity systems and selection (switching) is based on their output signal power values. Each microdiversity system is of MRC (maximal ratio combining) type with arbitrary number of branches in the presence of correlative Nakagami- m fading. We have derived the infinite-series expressions for LCR (level crossing rate) and AFD (average fading duration) at the output of this system. Numerical results are also presented in order to show the influence of various parameters such as number of the diversity branches at the microcmbiners, fading severity and level of correlation between those branches on the system's statistics, and then compared to the previously published results from this area.