Performance Analysis of DCT and WDCT Algorithms in Image Steganography

Frequency domain techniques such as Discrete Cosine Transform (DCT) and Warped Discrete Cosine Transform (WDCT) ensures high accuracy when compared with the spatial domain techniques. Therefore, these image steganographic methods were evaluated using public datasets to compare the performance of DCT and WDCT. After performing different tests using the datasets in each of the algorithms, a comparative analysis is made in terms of the Peak Signal-to-Noise Ratio (PSNR) metrics. The results indicate that the stego image generated after embedding the secret acquires high imperceptibility and robustness. The performance of the WDCT algorithm is higher as compared to the DCT algorithm and the resultant images produced are very less prone to noise attacks. In DCT and WDCT algorithms, the cover image will be split based on 8×8 pixel blocks and 2D DCT is applied on each pixel. The secret will be embedded inside DCT coefficient and inverse 2D DCT is applied to recover the secret. Therefore, these image steganographic techniques can be adopted to transfer the confidential messages in different sectors. In the future, other data hiding methods using deep learning could be implemented to increase the robustness and imperceptibility of covert messages.

Dirlik and Tovo-Benasciutti Spectral Methods in Vibration Fatigue: A Review with a Historical Perspective

The frequency domain techniques (also known as “spectral methods”) prove significantly more efficient than the time domain fatigue life calculations, especially when they are used in conjunction with finite element analysis. Frequency domain methods are now well established, and suitable commercial software is commonly available. Among the existing techniques, the methods by Dirlik and by Tovo–Benasciutti (TB) have become the most used. This study presents the historical background and the motivation behind the development of these two spectral methods, by also emphasizing their application and possible limitations. It further presents a brief review of the other spectral methods available for cycle counting directly from the power spectral density of the random loading. Finally, some ideas for future work are suggested.

Discrete Cosine Transform-Domain Based Video Steganography using Multiple Object Tracking

In the current era, the need for transmission of confidential data is pivotal in all domains of technology. New methodologies are being proposed for this very purpose, each being developed on specific shortcomings of previously proposed methods. In this paper, one such method for embedding and communicating confidential information has been proposed which employs encryption and error correction algorithms to further improve the reliability and robustness of the system. First, the information is preprocessed by encrypting the text using RC4 algorithm. The encrypted text is processed using hamming codes (4,7) to improve its reliability. After the pre-processing stage, the video is processed to identify reliable motion regions using the MOT (Multiple Object Tracking) algorithm. The identified regions are used to embed the confidential text by calculating its DCT coefficients and manipulating its values to embed the information. The non-motion region is used to store the key used during the pre-processing stage. This completes the processes at the transmitter’s part. The inverse of the process-extraction and decoding is applied at the receiver’s side to retrieve the confidential piece of information being transferred. The proposed methodology further focusses on comparing the visual quality and hiding capacity achieved by adopting DCT and DWT algorithms, to determine the better of the two frequency domain techniques in steganographic applications.

Optimal Quantitative H_2 Controller Design for Twin Rotor MIMO System

In this paper, the control approach is used for achieving the desired performance and stability of the twin-rotor MIMO system. This system is considered one of the complex multiple inputs of multiple-output systems. The complexity because of the high nonlinearity, significant cross-coupling and parameter uncertainty makes the control of such systems is a very challenging task. The dynamic of the Twin Rotor MIMO System (TRMS) is the same as that in helicopters in many aspects. The Quantitative Feedback Theory (QFT) controller is added to the control to enhance the control algorithm and to satisfy a more desirable performance. QFT is one of the frequency domain techniques that is used to achieve a desirable robust control in presence of system parameters variation. Therefore, a combination between control and QFT is presented in this paper to give a new efficient control algorithm. On the other hand, to obtain the optimal values of the controller parameters, Particle Swarm Optimization (PSO) which is one of the powerful optimization methods is used. The results show that the proposed quantitative control can achieve more desirable performance in comparison to control especially in attenuating the cross-coupling and eliminating the steady-state error.

EEG Analysis during Music Perception

This review presents the most interesting results of electroencephalographic studies on musical perception performed with different analysis techniques. In first place, concepts on intra-musical characteristics such as tonality, rhythm, dissonance or musical syntax, which have been object of further investigation, are introduced. Most of the studies found use listening musical extracts, sequences of notes or chords as an experimental situation, with the participants in a resting situation. There are few works with participants performing or imagining musical performance. The reviewed works have been divided into two groups: a) those that analyze the EEGs recorded in different cortical areas separately using frequency domain techniques: spectral power, phase or time domain EEG procedures such as potentials event related (ERP); b) those that investigate the interdependence between different EEG channels to evaluate the functional connectivity between different cortical areas through different statistical or synchronization indices. Most of the aspects studied in music-brain interaction are those related to musical emotions, syntax of different musical styles, musical expectation, differences between pleasant and unpleasant music and effects of musical familiarity and musical experience. Most of the works try to know the topographic maps of the brain centers, pathways and functions involved in these aspects.

High Frequency Fatigue and Using Frequency Domain Techniques

In recent years API 579 has provided the analyst with a detailed outline of the Wang-Brown algorithm (WBCC) for the cycle counting. The WBCC algorithm has become the generally accepted core of cycle counting implementations whenever multi-axial non-proportional fatigue stress histories are encountered. However, for vibration based fatigue, in the absence of any time history at all; it is common in industry to assess fatigue using frequency domain techniques. This paper presents special considerations for determination of the spectral stress fatigue in the spirit of API 579. In the frequency domain the stress cycles are counted a priori as a set of complex vectors. These complex stress vectors may represent the full stress tensor of a reduced set in an appropriate sub-space. The phase relationship between the vectors represents the time delay between the stress components of the stress field. This paper presents some of the actions that are necessary in order to accurately capture the phase relationships. It is often the case that the physics of the driving loads are either unknown or too complex to practically model. This is the case for complex fluid and particle interactions with vessel shells, piping or other wetted surfaces. This paper presents some tools and techniques that can be applied in order to characterize the loading spectrum in a manner which is specifically designed to capture the important fatigue characteristics. Any fatigue estimation technique must convert the stress vector set into a singularly dimensioned scalar metric that represents the stress amplitude of a cycle. However, the maximum stress amplitude from the cycle is not immediately accessible from the complex stress vectors. While a number of papers present techniques that are intended to calculate the maximum stress amplitude in the case where the stress metric is the equivalent stress this paper provides a slightly more general relation for the phase of the maximum amplitude. Finally the analyst must compare their calculated fatigue stress amplitudes to the API 579 fatigue curves. Closed form expressions for mono-linear spectral fatigue have been extensively investigated in the literature but more complex fatigue curves do not have such simple solutions. To this end this paper investigates the smooth bar carbon steel fatigue curves of ASME VIII-2.

Cognitive Rehabilitation and EEG Analysis: A Review

Cognition is the capacity of the brain to register and decipher data dependent on information and experience. A portion of the subjective aptitudes are processing, memory and retention, logic and reasoning, attention and so forth. The subjective abilities begin to grow directly from the hour of birth of a person. There are situations where these advancements don't happen at the opportune time or in a proficient manner, which prompts scholarly disorders. The most commonly found intellectual disorders in children are attention deficit hyperactivity disorder (ADHD), epilepsy, encephalitis, autism spectrum disorder (ASD) and speech disorders. There are cognitive tasks and retraining intended for each sort of cognitive issue. These are planned so as to improve the cognitive degrees of the children who experience the ill effects of cognitive issues, for an improvement in their everyday lives. This paper gives an overview of some of the existing techniques for the improvement of cognitive levels along with the techniques of EEG analysis. The activities in the brain can be traced with the help of an electroencephalogram (EEG). Cognitive levels can also be studied with the help of EEG. The study that involves cognition requires careful pre-processing, feature extraction and appropriate analysis. The processed EEG information is analysed utilizing various techniques which can extensively be ordered into time domain, time frequency domain, frequency domain, non-linear methods and artificial neural network methods. Out of every one of these strategies, the frequency domain techniques and time-frequency strategies are most popularly used.

A Nondestructive Testing Method for the Determination of the Complex Refractive Index Using Ultra Wideband Radar in Industrial Applications

An ultra-wide band radar reflection measurement technique for industrial applications is introduced. A new method for determining the complex refractive index (or equivalently the relative permittivity) of objects with planar interfaces is presented. The object thickness can also be obtained experimentally. The method is a combination of time and frequency domain techniques. The objects can be finite in size and at a finite distance. The limits in size and distance for the method to be valid are experimentally investigated. The method is relatively insensitive to hardware impairments such as frequency dependence of antennas and analog front end. The method is designed for industrial in-line measurements on objects on conveyor belts. Results are presented for solid wood and wood chips; the complex refractive index is determined in the frequency range 0.5 to 2.0 GHz for the moisture content of 3.6–10% for solid wood and 30–50% for wood chips. Polarimetric measurements are used; wood and wood chips are anisotropic.