38 research outputs found

    Leveraging Inlier Correspondences Proportion for Point Cloud Registration

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    In feature-learning based point cloud registration, the correct correspondence construction is vital for the subsequent transformation estimation. However, it is still a challenge to extract discriminative features from point cloud, especially when the input is partial and composed by indistinguishable surfaces (planes, smooth surfaces, etc.). As a result, the proportion of inlier correspondences that precisely match points between two unaligned point clouds is beyond satisfaction. Motivated by this, we devise several techniques to promote feature-learning based point cloud registration performance by leveraging inlier correspondences proportion: a pyramid hierarchy decoder to characterize point features in multiple scales, a consistent voting strategy to maintain consistent correspondences and a geometry guided encoding module to take geometric characteristics into consideration. Based on the above techniques, We build our Geometry-guided Consistent Network (GCNet), and challenge GCNet by indoor, outdoor and object-centric synthetic datasets. Comprehensive experiments demonstrate that GCNet outperforms the state-of-the-art methods and the techniques used in GCNet is model-agnostic, which could be easily migrated to other feature-based deep learning or traditional registration methods, and dramatically improve the performance. The code is available at https://github.com/zhulf0804/NgeNet

    Quality Investigations on Ground Improvement in Highway Engineering Practice

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    The constructions of highway often pass through naturally-deposited liquefiable grounds. Anti-earthquake design is essential for highway engineering practice in east China. Gravel column and dynamic compaction are often adopted for the improvements of such problematical grounds. The stability and settlement of the treated grounds depend much on the construction quality. How to investigate the quality of ground improvement is an important issue in highway engineering practice. In this study, the method of Spectral-Analysis-of-Surface-Waves (SASW) is applied to evaluate the construction quality on ground improvements by vibration gravel piles and dynamic compaction technique. The case studies show that the SASW method is a powerful way for investigating the improvement quality in highway engineering practice. The shear wave velocity measured in SASW has a relative good relationship with the N value measured in standard penetration tests

    Facile One-Pot Synthesis of Self-Assembled Folate-Biotin-Pullulan Nanoparticles for Targeted Intracellular Anticancer Drug Delivery

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    The self-assembled folate-biotin-pullulan (FBP) nanoparticles (NPs) were prepared by facile one-pot synthesis and their physicochemical properties were characterized. The self-assembled FBP NPs were used as an anticancer drug nanocarrier entrapping doxorubicin (DOX) for targeting folate-receptors-overexpressing cancer cells. The identification of prepared NPs to folate-receptor-expressing cancer cells (KB cells) was affirmed by cell viability measurement, folate competition test, and flow cytometric analysis. Compared with the naked DOX and DOX/BP NPs, the DOX/FBP NPs had lower IC50 value compared to KB cells as a result of the folate-receptor-mediated endocytosis process. The cytotoxicity of DOX/FBP NPs to KB cells could be inhibited competitively by free folate. The cellular intake pattern of naked DOX and drug-loaded NPs was identified by confocal laser scanning microscopy (CLSM) observation and the higher cellular uptake of drug for DOX/FBP NPs over naked DOX was observed. The prepared FBP NPs had the potential to be used as a powerful carrier to target anticancer drugs to folate-receptor-expressing tumor cells and reduce cytotoxicity to normal tissues

    Cronkhite-Canada syndrome associated with rib fractures: a case report

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    <p>Abstract</p> <p>Background</p> <p>Cronkhite-Canada syndrome (CCS) is a rare multiple gastrointestinal polyposis. Up till now, many complications of CCS have been reported in the literature, but rib fracture is not included.</p> <p>Case Presentation</p> <p>We report a case of a 58-year-old man who was admitted to our hospital with a 6-month history of frequent diarrhea, intermittent hematochezia and a weight loss of 13 kg. On admission, physical examination revealed alopecia of the scalp, hyperpigmentation of the hands and soles, and dystrophy of the fingernails. Laboratory data revealed hypocalcaemia and hypoproteinemia. Esophagogastroduodenoscopy, video capsule endoscopy and colonoscopy revealed various sizes of generalized gastrointestinal polyps. Histological examination of the biopsy specimens obtained from the stomach and the colon showed adenomatous polyp and inflammatory polyp respectively. Thus, a diagnosis of CCS was made. After treatment with corticosteroids for 24 days and nutritional support for two months, his clinical condition improved. Two months later, he was admitted to our hospital for the second time with frequent diarrhea and weight loss. The chest radiography revealed fractures of the left sixth and seventh ribs. Examinations, including emission computed tomography, bone densitometry test, and other serum parameters, were performed, but could not identify the definite etiology of the rib fractures. One month later, the patient suffered from aggravating multiple rib fractures due to the ineffective treatment, persistent hypocalcaemia and malnutrition.</p> <p>Conclusions</p> <p>This is the first case of a CCS patient with multiple rib fractures. Although the association between CCS and multiple rib fractures in this case remains uncertain, we presume that persistent hypocalcaemia and malnutrition contribute to this situation, or at least aggravate this rare complication. Besides, since prolonged corticosteroid therapy will result in an increased risk of osteoporotic fracture, CCS patients who accept corticosteroid therapy could be potential victims of rib fracture.</p

    Local dynamic neighborhood based outlier detection approach and its framework for large-scale datasets

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    Local outlier detection is a hot area and great challenge in data mining, especially for large-scale datasets. On the one hand, traditional algorithms often achieve low-quality detection results and are sensitive to neighborhood size. On the other hand, they are infeasible for large-scale datasets due to at least O(N2) time and space complexity. In light of these, we propose a new local outlier detection algorithm, which is designed based on a new stable neighborhood strategy-dynamic references nearest neighbors (DRNN). Meanwhile, we present a new detection framework by combining the proposed approach and k-mean for large-scale datasets. Experimental results demonstrate that the proposed algorithm can produce higher quality and robust detection results compared to several classic methods. Meanwhile, the new detection framework is able to significantly improve detecting efficiency without sacrificing accuracy

    OCT-Precoding Combined with LDPC-Coding Scheme for 128 QAM MB-OFDM UWBoF System

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    In this paper, we proposed a coding scheme based on orthogonal cyclic transpose (OCT) precoding combined with low-density parity check (LDPC) code to improve the transmission performance of 128-quadrature amplitude modulation multiband orthogonal-frequency-division-multiplexing ultrawide band over fiber (128 QAM MB-OFDM UWBoF) system. The proposed scheme could not only improve the performance of the system but also average the signal-to-noise ratio (SNR) of subcarriers and reduce the difference among subchannels in practical application. The simulation results showed that compared with the traditional scheme, the receiver performance of this scheme was improved by 2.7 dB when the LDPC-coding rate was 87.5% through 70 km standard single mode fiber (SSMF) transmission and the bit error rate (BER) was 3.8 × 10−3. Besides, the constellation distribution was more convergent and uniform

    Mesozoic sub-continental lithospheric mantle extension and related porphyry copper mineralization in South China

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    Most of the large porphyry copper deposits occurred in arc setting, which are closely related to oceanic crust subduction, especially to partial melting of mantle materials caused by dehydration of subducted plates. Recent studies have shown that porphyry copper deposits can occur in non-subduction setting, such as intra-continental and continental collision setting. The formation of porphyry copper deposits in continental collision setting is related to the partial melting of lithosphere modified by subduction. The fertilized magma emplaced in the shallow part of the crust through the crystallization differentiation and crustal contamination. However, the spatial and temporal distribution of porphyry copper deposits in the intra-continents setting are incompatible with the structures of the contemporary subduction zones, its genesis mechanism and dynamic process are not very clear. It has been a long intra-continental tectonic setting since the Paleozoic in South China. Three episodes porphyry copper systems (Early Jurassic, Late Jurassic and Early Cretaceous) occurred in Mesozoic, which related to the intra-continental tectonic setting. The Late Jurassic porphyry copper system was concurrent with the large-scale W-Sn mineralization in South China. The spatial and temporal distributions of these porphyry deposits are obviously inconsistent with those of the subduction-related porphyry copper system in southwestern USA and Cordilleran orogenic belt. The characteristics of sub-continental lithospheric mantle extension-related porphyry copper deposits is quite different from those occurred as linear formed in subduction, post-subduction extension, and continental collision setting. Especially, the porphyry copper deposits in the Early Cretaceous porphyry copper deposits which distributed as planar, which basically consistent with Mesozoic crustal thinning area in South China. Although the porphyry copper deposits of these three periods show arc magma affinity in geochemistry, the Nd-Sr isotope of the porphyries indicate the contribution of mantle to mineralization vary from the regions and the metallogenic types. The geological facts prove that the lithosphere of South China has undergone obvious extension during these three periods. The extent of lithospheric extension may vary in different regions of South China in each period. Therefore, we called the porphyry copper deposit from these three episodes as " intra-continental extensional porphyry copper deposit". The metallogenic mechanism of the Mesozoic intra-continental extensional porphyry copper deposits may be related to the upwelling of asthenosphere under the lithospheric extension background, which resulting in the transformation of the subcontinental lithospheric mantle or lower crust
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