421 research outputs found
Multi-Class Classification Averaging Fusion for Detecting Steganography
Multiple classifier fusion has the capability of increasing classification accuracy over individual classifier systems. This paper focuses on the development of a multi-class classification fusion based on weighted averaging of posterior class probabilities. This fusion system is applied to the steganography fingerprint domain, in which the classifier identifies the statistical patterns in an image which distinguish one steganography algorithm from another. Specifically we focus on algorithms in which jpeg images provide the cover in order to communicate covertly. The embedding methods targeted are F5, JSteg, Model Based, OutGuess, and StegHide. The developed multi-class steganalvsis system consists of three levels: (1) feature preprocessing in which a projection function maps the input vectors into a separable space, (2) classifier system using an ensemble of classifiers, and (3) two weighted fusion techniques are compared, the first is a well known variance weighted fusion and an Gaussian weighted fusion. Results show that through the novel addition of the classifier fusion step to the multi-class steganalysis system, the classification accuracy is improved by up to 12%
Steganalysis Embedding Percentage Determination with Learning Vector Quantization
Steganography (stego) is used primarily when the very existence of a communication signal is to be kept covert. Detecting the presence of stego is a very difficult problem which is made even more difficult when the embedding technique is not known. This article presents an investigation of the process and necessary considerations inherent in the development of a new method applied for the detection of hidden data within digital images. We demonstrate the effectiveness of learning vector quantization (LVQ) as a clustering technique which assists in discerning clean or non-stego images from anomalous or stego images. This comparison is conducted using 7 featuresover a small set of 200 observations with varying levels of embedded information from 1% to 10% in increments of 1%. The results demonstrate that LVQ not only more accurately identify when an image contains LSB hidden information when compared to k-means or using just the raw feature sets, but also provides a simple method for determining the percentage of embedding given low information embedding percentages. Abstract ©2006 IEEE
Análisis del compromiso deportivo de jĂłvenes waterpolistas: Un estudio basado en la TeorĂa de la AutoDeterminaciĂłn
Fundamentado en la TeorĂa de la AutodeterminaciĂłn (TAD), el objetivo del estudio fue analizar la relaciĂłn entre la percepciĂłn de jĂłvenes waterpolistas sobre el estilo interpersonal del entrenador, la satisfacciĂłn y frustraciĂłn de sus necesidades psicolĂłgicas básicas (NPB), la motivaciĂłn autodeterminada y su compromiso deportivo. Participaron 77 jugadores de waterpolo con una edad comprendida entre los 13 y los 20 años (M = 15.00, DT = 1.70). Los resultados mostraron que la percepciĂłn de los jugadores de un estilo de apoyo a la autonomĂa del entrenador, la satisfacciĂłn de las NPB, la motivaciĂłn intrĂnseca y el compromiso deportivo se relacionaba positiva y significativamente, siguiendo la secuencia establecida en la TAD. En sentido contrario, el estilo controlador percibido por los jugadores se relacionaba positiva y significativamente con la frustraciĂłn de las NPB y la desmotivaciĂłn y negativamente con el compromiso deportivo. Los resultados destacan la importancia del estilo interpersonal del entrenador sobre los procesos motivacionales y el compromiso deportivo de los jĂłvenes waterpolistas.
Grounded in Self-Determination Theory (SDT), the aim of this study was to analyze the relationship between waterpolo players perception on coach interpersonal style, satisfaction and frustration of their basic psychological needs (BPN), self-determined motivation and sport commitment. 77 male water polo players, with ages between 13 and 20 years old (M = 15.00, SD = 1.70), took part in the study. Results showed that players' perception of autonomy support coaching style was related positively and significantly with the satisfaction of BPN, intrinsic motivation and sport commitment, following established sequence in SDT. However, controlling coaching style was related positively and significantly with the frustration of BPN, amotivation and negatively with sport commitment. The results highlight the importance of coach interpersonal style on motivational processes and the sports commitment of young water polo players
Analysis of gene expression data from non-small celllung carcinoma cell lines reveals distinct sub-classesfrom those identified at the phenotype level
Microarray data from cell lines of Non-Small Cell Lung Carcinoma (NSCLC) can be used to look for differences in gene expression between the cell lines derived from different tumour samples, and to investigate if these differences can be used to cluster the cell lines into distinct groups. Dividing the cell lines into classes can help to improve diagnosis and the development of screens for new drug candidates. The micro-array data is first subjected to quality control analysis and then subsequently normalised using three alternate methods to reduce the chances of differences being artefacts resulting from the normalisation process. The final clustering into sub-classes was carried out in a conservative manner such that subclasses were consistent across all three normalisation methods. If there is structure in the cell line population it was expected that this would agree with histological classifications, but this was not found to be the case. To check the biological consistency of the sub-classes the set of most strongly differentially expressed genes was be identified for each pair of clusters to check if the genes that most strongly define sub-classes have biological functions consistent with NSCLC
Kinome rewiring reveals AURKA limits PI3K-pathway inhibitor efficacy in breast cancer.
Dysregulation of the PI3K-AKT-mTOR signaling network is a prominent feature of breast cancers. However, clinical responses to drugs targeting this pathway have been modest, possibly because of dynamic changes in cellular signaling that drive resistance and limit drug efficacy. Using a quantitative chemoproteomics approach, we mapped kinome dynamics in response to inhibitors of this pathway and identified signaling changes that correlate with drug sensitivity. Maintenance of AURKA after drug treatment was associated with resistance in breast cancer models. Incomplete inhibition of AURKA was a common source of therapy failure, and combinations of PI3K, AKT or mTOR inhibitors with the AURKA inhibitor MLN8237 were highly synergistic and durably suppressed mTOR signaling, resulting in apoptosis and tumor regression in vivo. This signaling map identifies survival factors whose presence limits the efficacy of targeted therapies and reveals new drug combinations that may unlock the full potential of PI3K-AKT-mTOR pathway inhibitors in breast cancer
High-throughput identification of genotype-specific cancer vulnerabilities in mixtures of barcoded tumor cell lines.
Hundreds of genetically characterized cell lines are available for the discovery of genotype-specific cancer vulnerabilities. However, screening large numbers of compounds against large numbers of cell lines is currently impractical, and such experiments are often difficult to control. Here we report a method called PRISM that allows pooled screening of mixtures of cancer cell lines by labeling each cell line with 24-nucleotide barcodes. PRISM revealed the expected patterns of cell killing seen in conventional (unpooled) assays. In a screen of 102 cell lines across 8,400 compounds, PRISM led to the identification of BRD-7880 as a potent and highly specific inhibitor of aurora kinases B and C. Cell line pools also efficiently formed tumors as xenografts, and PRISM recapitulated the expected pattern of erlotinib sensitivity in vivo
Corrigendum to: Comparative study of obstetric antiphospholipid syndrome (OAPS) and non-criteria obstetric APS (NC-OAPS): report of 1640 cases from EUROAPS registry
Rheumatology 2020;59:1306–1314. doi:https://doi.org/10.1093/rheumatology/kez419
In the original article, the affiliation of co-author Cecilia Beatrice Chighizola should have read: “Experimental Laboratory of Immunological and Rheumatologic Researches, Istituto Auxologico Italiano, IRCCS, Cusano Milanino, Milan, Italy”. These details have been corrected only in this corrigendum to preserve the published version of record
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