Mul-GAD: a semi-supervised graph anomaly detection framework via aggregating multi-view information

Anomaly detection is defined as discovering patterns that do not conform to the expected behavior. Previously, anomaly detection was mostly conducted using traditional shallow learning techniques, but with little improvement. As the emergence of graph neural networks (GNN), graph anomaly detection has been greatly developed. However, recent studies have shown that GNN-based methods encounter challenge, in that no graph anomaly detection algorithm can perform generalization on most datasets. To bridge the tap, we propose a multi-view fusion approach for graph anomaly detection (Mul-GAD). The view-level fusion captures the extent of significance between different views, while the feature-level fusion makes full use of complementary information. We theoretically and experimentally elaborate the effectiveness of the fusion strategies. For a more comprehensive conclusion, we further investigate the effect of the objective function and the number of fused views on detection performance. Exploiting these findings, our Mul-GAD is proposed equipped with fusion strategies and the well-performed objective function. Compared with other state-of-the-art detection methods, we achieve a better detection performance and generalization in most scenarios via a series of experiments conducted on Pubmed, Amazon Computer, Amazon Photo, Weibo and Books. Our code is available at https://github.com/liuyishoua/Mul-Graph-Fusion.Comment: Graph anomaly detection on attribute networ

Adaptive digital watermarking scheme based on support vector machines and optimized genetic algorithm

Digital watermarking is an effective solution to the problem of copyright protection, thus maintaining the security of digital products in the network. An improved scheme to increase the robustness of embedded information on the basis of discrete cosine transform (DCT) domain is proposed in this study. The embedding process consisted of two main procedures. Firstly, the embedding intensity with support vector machines (SVMs) was adaptively strengthened by training 1600 image blocks which are of different texture and luminance. Secondly, the embedding position with the optimized genetic algorithm (GA) was selected. To optimize GA, the best individual in the first place of each generation directly went into the next generation, and the best individual in the second position participated in the crossover and the mutation process. The transparency reaches 40.5 when GA’s generation number is 200. A case study was conducted on a 256 × 256 standard Lena image with the proposed method. After various attacks (such as cropping, JPEG compression, Gaussian low-pass filtering (3, 0. 5), histogram equalization, and contrast increasing (0.5, 0.6)) on the watermarked image, the extracted watermark was compared with the original one. Results demonstrate that the watermark can be effectively recovered after these attacks. Even though the algorithm is weak against rotation attacks, it provides high quality in imperceptibility and robustness and hence it is a successful candidate for implementing novel image watermarking scheme meeting real timelines

Oral care measures for preventing nursing home‐acquired pneumonia

Background Pneumonia occurring in residents of long-term care facilities and nursing homes can be termed 'nursing home-acquired pneumonia' (NHAP). NHAP is the leading cause of mortality among residents. NHAP may be caused by aspiration of oropharyngeal flora into the lung, and by failure of the individual's defence mechanisms to eliminate the aspirated bacteria. Oral care measures to remove or disrupt oral plaque might be effective in reducing the risk of NHAP. Objectives To assess effects of oral care measures for preventing nursing home-acquired pneumonia in residents of nursing homes and other long-term care facilities. Search methods Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 15 November 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2017, Issue 10), MEDLINE Ovid (1946 to 15 November 2017), and Embase Ovid (1980 to 15 November 2017) and Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1937 to 15 November 2017). The US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. We also searched the Chinese Biomedical Literature Database, the China National Knowledge Infrastructure, and the Sciencepaper Online to 20 November 2017. Selection criteria We included randomised controlled trials (RCTs) that evaluated the effects of oral care measures (brushing, swabbing, denture cleaning mouthrinse, or combination) in residents of any age in nursing homes and other long-term care facilities. Data collection and analysis At least two review authors independently assessed search results, extracted data, and assessed risk of bias in the included studies. We contacted study authors for additional information. We pooled data from studies with similar interventions and outcomes. We reported risk ratio (RR) for dichotomous outcomes, mean difference (MD) for continuous outcomes, and hazard ratio (HR) for time-to-event outcomes, using random-effects models. Main results We included four RCTs (3905 participants), all of which were at high risk of bias. The studies all evaluated one comparison: professional oral care versus usual oral care. We did not pool the results from one study (N = 834 participants), which was stopped at interim analysis due to lack of a clear difference between groups. We were unable to determine whether professional oral care resulted in a lower incidence rate of NHAP compared with usual oral care over an 18-month period (hazard ratio 0.65, 95% CI 0.29 to 1.46; one study, 2513 participants analysed; low-quality evidence). We were also unable to determine whether professional oral care resulted in a lower number of first episodes of pneumonia compared with usual care over a 24-month period (RR 0.61, 95% CI 0.37 to 1.01; one study, 366 participants analysed; low-quality evidence). There was low-quality evidence from two studies that professional oral care may reduce the risk of pneumonia-associated mortality compared with usual oral care at 24-month follow-up (RR 0.41, 95% CI 0.24 to 0.72, 507 participants analysed). We were uncertain whether or not professional oral care may reduce all-cause mortality compared to usual care, when measured at 24-month follow-up (RR 0.55, 95% CI 0.27 to 1.15; one study, 141 participants analysed; very low-quality evidence). Only one study (834 participants randomised) measured adverse effects of the interventions. The study identified no serious events and 64 non-serious events, the most common of which were oral cavity disturbances (not defined) and dental staining. No studies evaluated oral care versus no oral care. Authors' conclusions Although low-quality evidence suggests that professional oral care could reduce mortality due to pneumonia in nursing home residents when compared to usual care, this finding must be considered with caution. Evidence for other outcomes is inconclusive. We found no high-quality evidence to determine which oral care measures are most effective for reducing nursing home-acquired pneumonia. Further trials are needed to draw reliable conclusions

Adaptive robust blind watermarking scheme improved by entropy-based SVM and optimized quantum genetic algorithm

With the intensive study of machine learning in digital watermarking, its ability to balance the robustness and transparency of watermarking technology has attracted researchers’ attention. Therefore, quantum genetic algorithm, which serves as an intelligent optimized scheme combined with biological genetic mechanism and quantum computing, is widely used in various fields. In this study, an adaptive robust blind watermarking algorithm by means of optimized quantum genetics (OQGA) and entropy classification-based SVM (support vector machine) is proposed. The host image was divided into two parts according to the odd and even rows of the host image. One part was transformed by DCT (discrete cosine transform), and then the embedding intensity and position were separately trained by entropy-based SVM and OQGA; the other part was by DWT (discrete wavelet transform), in which the key fusion was achieved by an ergodic matrix to embed the watermark. Simulation results indicate the proposed algorithm ensures the watermark scheme transparency as well as having better resistance to common attacks such as lossy JPEG compression, image darken, Gaussian low-pass filtering, contrast decreasing, salt-pepper noise, and geometric attacks such as rotation and cropping. Received 22 May 2019 Revised 18 Aug 2019 Accepted 17 Sep 2019 Published 28 Oct 201

Periodontal therapy for primary or secondary prevention of cardiovascular disease in people with periodontitis

Background There may be an association between periodontitis and cardiovascular disease (CVD); however, the evidence so far has been uncertain about whether periodontal therapy can help prevent CVD in people diagnosed with chronic periodontitis. This is the second update of a review originally published in 2014, and first updated in 2017. Although there is a new multidimensional staging and grading system for periodontitis, we have retained the label 'chronic periodontitis' in this version of the review since available studies are based on the previous classification system. Objectives To investigate the effects of periodontal therapy for primary or secondary prevention of CVD in people with chronic periodontitis. Search methods Cochrane Oral Health's Information Specialist searched the Cochrane Oral Health's Trials Register, CENTRAL, MEDLINE, Embase, and CINAHL, two trials registries, and the grey literature to September 2019. We placed no restrictions on the language or date of publication. We also searched the Chinese BioMedical Literature Database, the China National Knowledge Infrastructure, the VIP database, and Sciencepaper Online to August 2019. Selection criteria We included randomised controlled trials (RCTs) that compared active periodontal therapy to no periodontal treatment or a different periodontal treatment. We included studies of participants with a diagnosis of chronic periodontitis, either with CVD (secondary prevention studies) or without CVD (primary prevention studies). Data collection and analysis Two review authors carried out the study identification, data extraction, and 'Risk of bias' assessment independently and in duplicate. They resolved any discrepancies by discussion, or with a third review author. We adopted a formal pilot‐tested data extraction form, and used the Cochrane tool to assess the risk of bias in the studies. We used GRADE criteria to assess the certainty of the evidence. Main results We included two RCTs in the review. One study focused on the primary prevention of CVD, and the other addressed secondary prevention. We evaluated both as being at high risk of bias. Our primary outcomes of interest were death (all‐cause and CVD‐related) and all cardiovascular events, measured at one‐year follow‐up or longer. For primary prevention of CVD in participants with periodontitis and metabolic syndrome, one study (165 participants) provided very low‐certainty evidence. There was only one death in the study; we were unable to determine whether scaling and root planning plus amoxicillin and metronidazole could reduce incidence of all‐cause death (Peto odds ratio (OR) 7.48, 95% confidence interval (CI) 0.15 to 376.98), or all CVD‐related death (Peto OR 7.48, 95% CI 0.15 to 376.98). We could not exclude the possibility that scaling and root planning plus amoxicillin and metronidazole could increase cardiovascular events (Peto OR 7.77, 95% CI 1.07 to 56.1) compared with supragingival scaling measured at 12‐month follow‐up. For secondary prevention of CVD, one pilot study randomised 303 participants to receive scaling and root planning plus oral hygiene instruction (periodontal treatment) or oral hygiene instruction plus a copy of radiographs and recommendation to follow‐up with a dentist (community care). As cardiovascular events had been measured for different time periods of between 6 and 25 months, and only 37 participants were available with at least one‐year follow‐up, we did not consider the data to be sufficiently robust for inclusion in this review. The study did not evaluate all‐cause death and all CVD‐related death. We are unable to draw any conclusions about the effects of periodontal therapy on secondary prevention of CVD. Authors' conclusions For primary prevention of cardiovascular disease (CVD) in people diagnosed with periodontitis and metabolic syndrome, very low‐certainty evidence was inconclusive about the effects of scaling and root planning plus antibiotics compared to supragingival scaling. There is no reliable evidence available regarding secondary prevention of CVD in people diagnosed with chronic periodontitis and CVD. Further trials are needed to reach conclusions about whether treatment for periodontal disease can help prevent occurrence or recurrence of CVD

Insight Into the Pico- and Nano-Phytoplankton Communities in the Deepest Biosphere, the Mariana Trench

As photoautotrophs, phytoplankton are generally present in the euphotic zone of the ocean, however, recently healthy phytoplankton cells were found to be also ubiquitous in the dark deep sea, i.e., at water depths between 2000 and 4000 m. The distributions of phytoplankton communities in much deeper waters, such as the hadal zone, are unclear. In this study, the vertical distribution of the pico- and nano-phytoplankton (PN) communities from the surface to 8320 m, including the epipelagic, mesopelagic, bathypelagic, and hadal zones, were investigated via both 18S and p23S rRNA gene analysis in the Challenger Deep of the Mariana Trench. The results showed that Dinoflagellata, Chrysophyceae, Haptophyta, Chlorophyta, Prochloraceae, Pseudanabaenaceae, Synechococcaceae, and Eustigmatophyceae, etc., were the predominant PN in the Mariana Trench. Redundancy analyses revealed that depth, followed by temperature, was the most important environmental factors correlated with vertical distribution of PN community. In the hadal zone, the PN community structure was considerably different from those in the shallower zones. Some PN communities, e.g., Eustigmatophyceae and Chrysophyceae, which have the heterotrophic characteristics, were sparse in shallower waters, while they were identified with high relative abundance (94.1% and 20.1%, respectively) at the depth of 8320 m. However, the dinoflagellates and Prochloraceae Prochlorococcus were detected throughout the entire water column. We proposed that vertical sinking, heterotrophic metabolism, and/or the transition to resting stage of phytoplankton might contribute to the presence of phytoplankton in the hadal zone. This study provided insight into the PN community in the Mariana Trench, implied the significance of phytoplankton in exporting organic matters from the euphotic to the hadal zone, and also hinted the possible existence of some undetermined energy metabolism (e.g., heterotrophy) of phytoplankton making themselves adapt and survive in the hadal environment