Varying radix numeral system based adaptive image steganography

A novel image steganographic scheme based on the primitive and renowned numerical model is proposed. In this adaptive scheme the data to be embedded is dissected into numerals, each having variable information carrying capacity. The dissection is based on the statistics of the host image pixels i.e. the amount of adulteration that a pixel can tolerate. The proposed method provides proficient visual quality despite high payload capacity. The experimental results evaluated on 300 natural images show that the new scheme is resistant to RS steganalysis and offers high visual quality when compared with typical LSB-based schemes as well as their edge adaptive versions, like pixel-value-differencing-based schemes.     

Disorder Tuned Superconductor Insulator Transition in La2−x (Sr/Ce) x CuO4 & NbN Superconducting Thin Films

In studying the magneto-resistivity ρ(B) in high pulsed magnetic fields up to 55 T, it is often observed that the ρ(B) curves for different temperatures in the vicinity of the critical temperature cross at the same field value, B=B _CP . We show how the crossing field changes as a function of the hole (or electron) doping x in La_2?x (Sr/Ce) _x CuO₄. The resistivity ρ and the magnetic field B at different temperatures may be scaled as R/R _CP and |B?B _CP|/T ^γ , respectively. This kind of scaling resulted in a conventional critical exponent γ=1/ν z=1.35 (ν z～0.74) in our La_2?x (Sr/Ce) _x CuO₄ thin films, and a much higher value of γ=4.35 (ν z～0.23) in the case of our disordered NbN films.     

Is There a General Factor in Ratings of Job Performance? A Meta-Analytic Framework for Disentangling Substantive and Error Influences.

A database integrating 90 years of empirical studies reporting intercorrelations among rated job performance dimensions was used to test the hypothesis of a general factor in job performance. After controlling for halo error and 3 other sources of measurement error, there remained a general factor in job performance ratings at the construct level accounting for 60% of total variance. Construct-level correlations among rated dimensions of job performance were substantially inflated by halo for both supervisory (33%) and peer (63%) intrarater correlations. These findings have important implications for the measurement of job performance and for theories of job performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Capacities of FDMA/CDMA systems in the presence of phase noise andmultipath Rayleigh fading

The effect of phase noise on the capacities of coherently demodulated hybrid frequency-division multiple access/code division multiple-access (FDMA/CDMA) systems operating over a multipath Rayleigh fading channel is investigated. Using an approximate upper bound on the bit-error rate performance, which has been derived and presented in a previous paper, the capacities of the FDMA/CDMA systems are estimated for several combinations of channel and system parameters. Simulation results are also included to show the effect of the bounding error     

Gender, age, and race differences on overt integrity tests: Results across four large-scale job applicant datasets.

Group differences on overt integrity tests were examined. Gender, age, and race differences were investigated using 724,806 job applicants. Women scored higher on overt integrity tests than men. There were very small differences between older job applicants (40 years old and older) and younger job applicants (younger than 40). No appreciable age-gender interactions were detected. Race differences were examined by comparing mean scores of Blacks, Hispanics, Asians, and American Indians with those of Whites and were found to be trivial. Implications for adverse impact, test construction, and personality measurement are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

BER analysis of QAM on fading channels with transmit diversity

In this letter, we derive analytical expressions for the bit error rate (BER) of space-time block codes (STBC) from complex orthogonal designs (COD) using quadrature amplitude modulation (QAM) on Rayleigh fading channels. We take a bit log-likelihood ratio (LLR) based approach to derive the BER expressions. The approach presented here can be used in the BER analysis of any STBC from COD with linear processing for any value of M in an M-QAM system. Here, we present the BER analysis and results for a 16-QAM system with i) (2-Tx, L-Rx) antennas using Alamouti code (rate-1 STBC), ii) (3-Tx, L-Rx) antennas using a rate-1/2 STBC, and iii) (5-Tx, L-Rx) antennas using a rate-7/11 STBC. In addition to being used in the BER analysis, the LLRs derived can also be used as soft inputs to decoders for various coded QAM schemes, including turbo coded QAM with space-time coding as in high speed downlink packet access (HSDPA) in 3G.     

Open‐loop power control performance in DS‐CDMA networks with frequency selective fading and non‐stationary base stations

In this paper, we study the performance of a simple and easy‐to‐implement distributed power control strategy applicable to direct sequence code division multiple access (DS‐CDMA) networks. The scheme makes use of the received power measurements made on the forward link at individual mobile units to control the transmit powers on their reverse links. The algorithm, which effectively compensates for the slowly varying distance and shadow losses (due to their high correlation on both forward and reverse links), attempts to minimize the effect of fast multipath fading by averaging it out. We adopt a quasi‐analytic approach to estimate the reverse link capacity performance of an open‐loop power control scheme in both a single cell and a multi‐cell environment, and we do this for both a fixed base station and a moving base station scenario. Non‐stationary base stations are typical in tactical and emergency communications scenarios where the base stations could be mounted on moving platforms (e.g., tanks, jeeps, unmanned airborne vehicles). We estimate the capacity degradation, when base stations move relative to other cells, as a function of the amount of cell overlap and the standard deviation of the power control error. We also provide a comparison of the performance of the open‐loop power control strategy with that of a closed‐loop power control strategy. This revised version was published online in July 2006 with corrections to the Cover Date.