39 research outputs found
Improving hand vein recognition by score weighted fusion of wavelet-domain multi-radius local binary patterns
Among biometric modalities, hand vein patterns are seen as providing an attractive method for high-level security access applications owing to high impenetrability and good user convenience. For biometric recognition based on near-infrared dorsal hand vein images, Local Binary Patterns (LBP) have emerged as a highly effective descriptor of local image texture with high recognition performance reported. In this paper, the traditional approach with LBP applied in the spatial domain is extended to multi-radius LBP in the wavelet domain to provide a more comprehensive set of feature categories to capture grey-level variation characteristics of vein patterns, and score weighted fusion based on the relative discriminative power of each feature category is proposed to achieve higher recognition performance. The proposed methodology is shown to provide a more robust performance with a recognition rate in excess of 99% and an equal error rate significantly less than 2%
OPCML Is a Broad Tumor Suppressor for Multiple Carcinomas and Lymphomas with Frequently Epigenetic Inactivation
Background: Identification of tumor suppressor genes (TSGs) silenced by CpG methylation uncovers the molecular mechanism of tumorigenesis and potential tumor biomarkers. Loss of heterozygosity at 11q25 is common multiple tumors including nasopharyngeal carcinoma (NPC). OPCML, located at 11q25, is one of the downregulated genes we identified through digital expression subtraction. Methodology/Principal Findings: Semi-quantitative RT-PCR showed frequent OPCML silencing in NPC and other common tumors, with no homozygous deletion detected by multiplex differential DNA-PCR. Instead, promoter methylation of OPCML was frequently detected in multiple carcinoma cell lines (nasopharyngeal, esophageal, lung, gastric, colon, liver, breast, cervix, prostate), lymphoma cell lines (non-Hodgkin and Hodgkin lymphoma, nasal NK/T-cell lymphoma) and primary tumors, but not in any non-tumor cell line and seldom weakly methylated in normal epithelial tissues. Pharmacological and genetic demethylation restored OPCML expression, indicating a direct epigenetic silencing. We further found that OPCML is stress-responsive, but this response is epigenetically impaired when its promoter becomes methylated. Ecotopic expression of OPCML led to significant inhibition of both anchorage-dependent and -indendent growth of carcinoma cells with endogenous silencing. Conlusions/Significance: Thus, through functional epigenetics, we identified OPCML as a broad tumor suppressor, which is frequently inactivated by methylation in multiple malignancies. © 2008 Cui et al.published_or_final_versio
Integrity evaluation of metallic aerostructures by trend analysis of acousto-ultrasonic signals
By attaching a network of piezoelectric transducers over a metallic aircraft fuselage panel, the paper shows the changes of multi-path acousto-ultrasonic (AU) signals which pass through the aerostructure under fatigue loading. Based on the whole life-cycle of the multi-path AU signals collected from a metallic aerostructure until complete fracture, two different trend analysis approaches are presented in detail for evaluation of structural deterioration. One is based on damage indices computed from the changes of the AU signals with respect to their baseline signals in terms of extracted waveform envelopes and phases, and the other is based on principal component analysis (PCA) to reveal the hidden variation patterns of the AU signals. Consistent trends are shown to be produced by both approaches. Whilst the relationship between the complete set of the multi-path AU signals acquired and the gradual deterioration in structural integrity is found to be represented by the statistical trends of the damage indices in the first approach, it is found to generally follow an inverse U-shape trajectory in the feature space formed by the two most significant principal bases in the second approach. Furthermore, the PCA results are shown to provide a good basis to develop an AU-based traffic light system for aerostructure integrity
Detection of Aircraft Component Defects Using Low Voltage Excitation of Ultrasonic Transducers
Large areas of composite primary structure are now to be found both on civil and military aircraft throughout the world and the inspection of these structures contributes significantly to overall operating costs. Therefore methods to reduce the inspection time, whilst maintaining an acceptable minimum defect detection capability, are required in order to optimize the potential cost saving benefits offered by using that carbon fiber composite material.</p
Exploratory study of a non-invasive method based on acoustic emission for assessing the dynamic integrity of knee joints
The paper presents the development of a new measurement system based on acoustic emission (AE) for assessing the dynamic integrity of knee joints, and the evaluation of its efficacy, through an exploratory study using healthy and osteoarthritic knees. For the former, the paper describes the system implemented to acquire joint angle-based AE and the protocol developed to obtain repeatable results. For the latter, the paper reports significant differences between healthy and osteoarthritic knees using statistical analysis of AE occurrence and distribution of AE features in different movement phases. Osteoarthritic knees are found to produce 6–10 times more acoustic emissions than healthy knees, with amplitudes which can be 20 dB higher, and durations which can be 10 times longer. These findings lead to a visual representation method of AE feature profiles based on multidimensional density of AE hits per repeated movement and the use of principal component analysis for objective assessment of the clinical status of knee joints