A Steganalytic Scheme Based on Classifier Selection Using Joint Image Characteristics

Steganalysis relies on steganalytic features and classification techniques. Because of the complexity and different characteristics of cover images, to make steganalysis more applicable toward detecting stego images in real applications, we need to train different classifiers so as to match different images according to their characteristics. Selection of classifiers according to characteristics of images is the key point to improve accuracy of steganalysis. In our work, we study the methods of classifier selection based on characteristics of images including image size, quantization factor, or matrix. Besides, we also discuss other characteristics, such as texture, cover source, which makes an appreciable difference to steganalysis.

A comparison between the two lobes of comet 67P/Churyumov–Gerasimenko based on D/H ratios in H2O measured with the Rosetta/ROSINA DFMS

ABSTRACT The nucleus of the Jupiter-family comet 67P/Churyumov–Gerasimenko was discovered to be bi-lobate in shape when the European Space Agency spacecraft Rosetta first approached it in 2014 July. The bi-lobate structure of the cometary nucleus has led to much discussion regarding the possible manner of its formation and on how the composition of each lobe might compare with that of the other. During its two-year-long mission from 2014 to 2016, Rosetta remained in close proximity to 67P/Churyumov–Gerasimenko, studying its coma and nucleus in situ. Based on lobe-specific measurements of HDO and H2O performed with the ROSINA Double Focusing Mass Spectrometer (DFMS) on board Rosetta, the deuterium-to-hydrogen (D/H) ratios in water from the two lobes can be compared. No appreciable difference was observed, suggesting that both lobes formed in the same region and are homogeneous in their D/H ratios.

Null effect of scratches made by curling rocks

There is disagreement in the literature as to whether scratches made by curling rocks affect the motion of subsequent curling rocks. The aim of this investigation is to provide unequivocal experimental evidence to resolve this disagreement. Such evidence has been obtained by comparing the curl distances (total lateral deflections) of rocks sliding over ice with no scratches to curl distances of rocks sliding over ice completely covered with scratches made by previous curling rocks. The result of this simple experiment is that there is no appreciable difference in the curl distances between the two ice conditions. The conclusion is that the scratches made by curling rocks do not affect the motion of other curling rocks and that the lateral deflection of curling rocks cannot solely be due to scratches made by curling rocks.

A Steganalytic Scheme Based on Classifier Selection Using Joint Image Characteristics

Steganalysis relies on steganalytic features and classification techniques. Because of the complexity and different characteristics of cover images, to make steganalysis more applicable toward detecting stego images in real applications, we need to train different classifiers so as to match different images according to their characteristics. Selection of classifiers according to characteristics of images is the key point to improve accuracy of steganalysis. In our work, we study the methods of classifier selection based on characteristics of images including image size, quantization factor, or matrix. Besides, we also discuss other characteristics, such as texture, cover source, which makes an appreciable difference to steganalysis.

Effect of Alloy Composition & Helium ion-irradiation on the Mechanical Properties of Tungsten, Tungsten-Tantalum & Tungsten-Rhenium for Fusion Power Applications

ABSTRACTModel alloys have been made of pure W and 1% & 5% W-Ta and W-Re. Indentation hardness and modulus data were obtained by nanoindentation to assess the effect of composition on mechanical properties. Results showed that both the Ta and Re compositions hardened with increasing alloy content, greater in the W-5%Ta composition which showed an increase of 1.03GPa (17%), compared to a 0.43GPa (7%) increase in W-5%Re. The samples also showed very small increases in modulus of ∼ 25GPa (6%) in both W-5%Re and W-5%Ta. The samples were implanted with 3000appm concentration of helium. All samples show a substantial increase in hardness of up to 107% in the case of pure W. An appreciable difference in modulus is also seen in all samples. Initial TEM work has shown no visible He bubbles, suggesting that the mechanical properties changes are due to He-vacancy cluster formation below the resolvable limit.

Synovial Sarcomas of the Head and Neck

Springing from mesenchyme rather than mature synovial tissues, synovial sarcomas are high-grade neoplasms that express epithelial as well as supporting tissue features. Accordingly, their histologic phenotypes can be epithelial, stromal, or mixed. Between 3% and 10% of all synovial sarcomas originate in the head and neck, particularly from parapharyngeal sites. These is no appreciable difference in biologic activity between synovial sarcomas of the head and neck and those arising from other anatomic sites. Five-year survivals are misleadingly optimistic and do not adequately reflect the natural history of the sarcoma. Synovial sarcoma is known to metastasize late, and few patients survive that event.

Hearing Aid Gain Usage by Children

Hearing aid gain usage by two groups of children was examined. No appreciable difference was noted between the groups, nor was there a clinically significant difference between gain usage by these children as compared with a sample of adult hearing aid wearers.

Light and Length of Stay in Hospital

A study was carried out to examine whether the time spent as an inpatient in hospital showed a seasonal dependence which could be attributed to differences in ambient lighting levels between summer and winter. It was found that the season of admission to hospital did not make any appreciable difference to how long patients took to recover before they were discharged.