Electronic states of PrCoO3_3: X-ray photoemission spectroscopy and LDA+U density of states studies

Electronic states of PrCoO$_3$ are studied using x-ray photoemission spectroscopy. Pr 3d$_{5/2}$ core level and valence band (VB) were recorded using Mg K$_\beta$ source. The core level spectrum shows that the 3d$_{5/2}$ level is split into two components of multiplicity 4 and 2, respectively due to coupling of the spin states of the hole in 3d$_{5/2}$ with Pr 4f holes spin state. The observed splitting is 4.5 eV. The VB spectrum is interpreted using density of states (DOS) calculations under LDA and LDA+U. It is noted that LDA is not sufficient to explain the observed VB spectrum. Inclusion of on-site Coulomb correlation for Co 3d electrons in LDA+U calculations gives DOS which is useful in qualitative explanation of the ground state. However, it is necessary to include interactions between Pr 4f electrons to get better agreement with experimental VB spectrum. It is seen that the VB consists of Pr 4f, Co 3d and O 2p states. Pr 4f, Co 3d and O 2p bands are highly mixed indicating strong hybridization of these three states. The band near the Fermi level has about equal contributions from Pr 4f and O 2p states with somewhat smaller contribution from Co 3d states. Thus in the Zaanen, Sawatzky, and Allen scheme PrCoO$_3$ can be considered as charge transfer insulator. The charge transfer energy $\Delta$ can be obtained using LDA DOS calculations and the Coulomb-exchange energy U' from LDA+U. The explicit values for PrCoO$_3$ are $\Delta$ = 3.9 eV and U' = 5.5 eV; the crystal field splitting and 3d bandwidth of Co ions are also found to be 2.8 and 1.8 eV, respectively.Comment: 12 pages, 7 figures; to appear J. Phys.: Condens. Matte

Pathophysiology of altered color perception

Human beings are able to perceive hundreds of shades of color which depends on the three types of cone system and various ratios of stimulation in response to different wavelengths. Perceptually and cognitively, men and women may experience appearance of color differently. The convention seems to be that women tend to prefer brighter and gratifying colors and men are more comfortable with stifled and soft colors. The reason may be linked to hormonal, developmental and environmental differences amongst both the sexes. The present review discusses various types of clinical and experimental studies done on alteration in color perception

Game Theoretic Approach for Cognitive Radio Networks

Cognitive radio is a promising approach to make efficient use of spectrum by rapidly adapting the changes in wireless environment. In such networks, nodes are expected to be aware of their environment and must be able to learn from the outcomes of past decisions. Game theory which comprise of analytical tools designed to study interactive decision-making processes can be applied effectively to solve some of such complex problems. This paper discusses the significance of using game theory for cognitive radio networks and resource allocation, and various game theoretic approaches used for it. DOI: 10.17762/ijritcc2321-8169.15059

Chemical synthesis and study of structural and optoelectronic properties of CdS thin films: Effect of SILAR growth cycles

CdS thin films were deposited on glass substrates by using successive ionic layer adsorption and reaction (SILAR) method at room temperature. The effect of SILAR growth cycles on structural, morphological, optical and electrical properties of the films has been studied. The thickness of the deposited film is measured by employing weight difference method. The X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) studies showed that all the films exhibit polycrystalline nature and are covered well with glass substrates. The values of average crystallite size were found to be 53 nm, 58 nm, 63 nm and 71 nm corresponding to the thin films deposited with 30, 40, 50 and 60 SILAR growth cycles respectively. From the UV–VIS spectra of the deposited thin films, it was seen that both the absorption properties and energy bandgap of the films changes with increasing number of SILAR growth cycles. A decrease of electrical resistivity has been observed with increasing SILAR growth cycles. &nbsp

A Review on Multilingual Text to Speech Synthesis by Syllabifying the Words of Devanagari and Roman

Speech synthesis is process of spoken language as an input text and converted into speech waveforms. This paper describes the text to speech system for Devanagari scripted language and Roman Language. There are many earliest TTS systems are available but for Devanagari and Roman scripts are not available

Digital Audio Watermarking using EMD for Voice Message Encryption with Added Security

Several accurate watermarking methods for image watermarking have being suggested and implemented to secure various forms of digital data, images and videos however, very few algorithms are proposed for audio watermarking. This is also because human audio system has dynamic range which is wider in comparison with human vision system. In this paper, a new audio watermarking algorithm for voice message encryption based on Empirical Mode Decomposition (EMD) is introduced. The audio signal is divided into frames and each frame is then decomposed adaptively, by EMD, into intrinsic oscillatory components called Intrinsic Mode Functions (IMFs). The watermark, which is the secret message that is to be sent, along with the synchronization codes are embedded into the extrema of the last IMF, a low frequency mode stable under different attacks and preserving the perceptual quality of the host signal. Based on exhaustive simulations, we show the robustness of the hidden watermark for audio compression, false decryption, re-quantization, resampling. The comparison analysis shows that our method has better performance than other steganography schemes recently reported

Image Segmentation and Classification for Medical Image Processing

Segmentation and labeling remains the weakest step in many medical vision applications. This paper illustrates an approach based on watershed transform which are designed to solve typical problems encountered in various applications, and which are controllable through adaptation of their parameters. Two of these modules are presented: the lung cancer detection, a method for the segmentation of cancer regions from CT images, a watershed algorithm for image segmentation and brain tumor detection from MRI images. Various GLCM features along with some statistical features are used for classification using Neural network and Support Vector Machine (SVM). We describe the principles of the algorithms and illustrate their generic properties by discussing the results of both applications in 2D MRI images of Brain tumor and CT images of lung cancer

BVPSMS: A Batch Verification Protocol for End-to-End Secure SMS for Mobile Users

Short Message Service (SMS) is a widely used communication medium for mobile applications, such as banking, social networking, and e-commerce. Applications of SMS services also include real-time broadcasting messages, such as notification of natural disasters and terrorist attacks, and sharing the current whereabouts to other users, such as notifying urgent business meeting information, transmitting quick information in the battlefield to multiple users, notifying current location to our friends, and sharing market information. However, traditional SMS is not designed with security in mind (e.g. messages are not securely sent). In this paper, we introduce a batch verification Authentication and Key Agreement (AKA) protocol, BVPSMS, which provides end-to-end message security over an insecure communication channel between different Mobile Subscribers (MSs). Specifically, the proposed protocol securely transmits SMS from one MS to multiple MS simultaneously. We then evaluate the performance of the BVPSMS protocol in terms of communication and computation overheads, protocol execution time, and batch and re-batch verification times. The impacts of the user mobility, and the time, space, and cost complexity analysis are also discussed. We present a formal proof of the proposed protocol. To the best of our knowledge, this is the first provably-secure batch verification AKA protocol, which provides end-to-end security to the SMS using symmetric keys