Outliers rejection in similar image matching

Background Image matching is crucial in numerous computer vision tasks such as 3D reconstruction and simultaneous visual localization and mapping.The accuracy of the matching significantly impacted subsequent studies.Because of their local similarity,when image pairs contain comparable patterns but feature pairs are positioned differently,incorrect recognition can occur as global motion consistency is disregarded.Methods This study proposes an image-matching filtering algorithm based on global motion consistency.It can be used as a subsequent matching filter for the initial matching results generated by other matching algorithms based on the principle of motion smoothness.A particular matching algorithm can first be used to perform the initial matching;then,the rotation and movement information of the global feature vectors are combined to effectively identify outlier matches.The principle is that if the matching result is accurate,the feature vectors formed by any matched point should have similar rotation angles and moving distances.Thus,global motion direction and global motion distance consistencies were used to reject outliers caused by similar patterns in different locations.Results Four datasets were used to test the effectiveness of the proposed method.Three datasets with similar patterns in different locations were used to test the results for similar images that could easily be incorrectly matched by other algorithms,and one commonly used dataset was used to test the results for the general image-matching problem.The experimental results suggest that the proposed method is more accurate than other state-of-the-art algorithms in identifying mismatches in the initial matching set.Conclusions The proposed outlier rejection matching method can significantly improve the matching accuracy for similar images with locally similar feature pairs in different locations and can provide more accurate matching results for subsequent computer vision tasks.

Seasonal increase in nest defense,but not egg rejection,in a cuckoo host

The interactions between avian brood parasites and their hosts provide an informative and easy-to-handle system for studying coevolution.Avian brood parasitism reduces the reproductive success of hosts,and thus,hosts have evolved anti-parasitic strategies,such as rejecting parasitic eggs and adopting aggressive nest defense strategies,to avoid the cost brought on by brood parasitism.To test whether host anti-parasitic strategies are adjusted with the risk of being parasitized when the breeding seasons of brood parasites and hosts are not synchronous,we conducted a field experiment assessing nest defense and egg recognition behaviors of the Isabelline Shrike(Lanius isabellinus),a host of the Common Cuckoo(Cuculus canorus).In the local area,the host Isabelline Shrike begins to breed in April,whereas the summer migratory Common Cuckoo migrates to the local area in May and begins to lay parasitic eggs.Results showed that nest defense behaviors of the Isabelline Shrike increases significantly after cuckoo arrival,showing higher aggressiveness to cuckoo dummies,with no significant difference in attack rates among cuckoo,sparrowhawk and dove dummies,but their egg rejection did not change significantly.These results imply that Isabelline Shrikes may adjust their nest defense behavior,but not egg rejection behavior,with seasonality.

Disturbances rejection optimization based on improved two-degree-of-freedom LADRC for permanent magnet synchronous motor systems

Permanent magnet synchronous motor(PMSM)speed control systems with conventional linear active disturbance rejection control(CLADRC)strategy encounter issues regarding the coupling between dynamic response and disturbance suppression and have poor performance in suppressing complex nonlinear disturbances.In order to address these issues,this paper proposes an improved two-degree-of-freedom LADRC(TDOF-LADRC)strategy,which can enhance the disturbance rejection performance of the system while decoupling entirely the system's dynamic and anti-disturbance performance to boost the system robustness and simplify controller parameter tuning.PMSM models that consider total disturbances are developed to design the TDOF-LADRC speed controller accurately.Moreover,to evaluate the control performance of the TDOF-LADRC strategy,its stability is proven,and the influence of each controller parameter on the system control performance is analyzed.Based on it,a comparison is made between the disturbance observation ability and anti-disturbance performance of TDOF-LADRC and CLADRC to prove the superiority of TDOF-LADRC in rejecting disturbances.Finally,experiments are performed on a 750 W PMSM experimental platform,and the results demonstrate that the proposed TDOF-LADRC exhibits the properties of two degrees of freedom and improves the disturbance rejection performance of the PMSM system.

Recognition and rejection of foreign eggs of different colors in Barn Swallows

Brood parasitic birds lay eggs in the nests of other birds,and the parasitized hosts can reduce the cost of raising unrelated offspring through the recognition of parasitic eggs.Hosts can adopt vision-based cognitive mechanisms to recognize foreign eggs by comparing the colors of foreign and host eggs.However,there is currently no uniform conclusion as to whether this comparison involves the single or multiple threshold decision rules.In this study,we tested both hypotheses by adding model eggs of different colors to the nests of Barn Swallows(Hirundo rustica)of two geographical populations breeding in Hainan and Heilongjiang Provinces in China.Results showed that Barn Swallows rejected more white model eggs(moderate mimetic to their own eggs)and blue model eggs(highly non-mimetic eggs with shorter reflectance spectrum)than red model eggs(highly nonmimetic eggs with longer reflectance spectrum).There was no difference in the rejection rate of model eggs between the two populations of Barn Swallows,and clutch size was not a factor affecting egg recognition.Our results are consistent with the single rejection threshold model.This study provides strong experimental evidence that the color of model eggs can has an important effect on egg recognition in Barn Swallows,opening up new avenues to uncover the evolution of cuckoo egg mimicry and explore the cognitive mechanisms underlying the visual recognition of foreign eggs by hosts.

Rejecting Outliers Based on Correspondence Manifold

发现在二幅图象之间的可靠的相应的点是在计算机视觉的一个基本问题，特别与 L 视觉框架的发展。这篇论文介绍歧管的通讯并且建议一个新奇计划由听说向上的看法拒绝孤立点歧管。建议计划独立于在出版工作要估计并且克服可得到的方法的下列限制的参量的模型：效率严厉地因孤立点百分比的增加和估计的模型参数的数字倒下；孤立点拒绝被结合模型选择和模型评价。真实图象对的实验显示出我们的建议计划的优秀性能。

To analyze the differentially expressed genes in chronic rejection after renal transplantation by bioinformatics

Objective: To use bioinformatics technology to analyse differentially expressed genes in chronic rejection after renal transplantation, we can screen out potential pathogenic targets associated with the development of this disease, providing a theoretical basis for finding new therapeutic targets. Methods: Gene microarray data were downloaded from the Gene Expression Profiling Integrated Database (GEO) and cross-calculated to identify differentially expressed genes (DEGs). Analysis of differentially expressed genes (DEGs) with gene ontology (GO) is a method used to study the differences in gene expression under different conditions as well as their functions and interrelationships, while Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis is a tool used to explore the functions and pathways of genes in specific biological processes. By calculating the distribution of immune cell infiltration, the result of immune infiltration in the rejection group can be analysed as a trait in Weighted Gene Co-Expression Network Analysis (WGCNA) for genes associated with rejection. Then, protein-protein interaction networks (PPI) were constructed using the STRING database and Cytoscape software to identify hub gene markers. Results: A total of 60 integrated DEGs were obtained from 3 datasets (GSE7392, GSE181757, GSE222889). By GO and KEGG analysis, the GEDs were mainly concentrated in the regulation of immune response, defence response, regulation of immune system processes, and stimulation response. The pathways were mainly enriched in antigen processing and presentation, EBV infection, graft-versus-host, allograft rejection, and natural killer cell-mediated cytotoxicity. After further screening using WGCNA and PPI networks, HLA-A, HLA-B, HLA-F, and TYROBP were identified as hub genes (Hub genes). The data GSE21374 with clinical information was selected to construct the diagnostic efficacy and risk prediction model plots of the four hub genes, and the results concluded that all four Hub genes had good diagnostic value (area under the curve in the range of 0.794-0.819). From the inference, it can be concluded that the four genes, HLA-A, HLA-B, HLA-F and TYROBP, may have an important role in the development and progression of chronic rejection after renal transplantation. Conclusion: DEGs play an important role in the study of the pathogenesis of chronic rejection after renal transplantation, and can provide theoretical support for further research on the pathogenesis of chronic rejection after renal transplantation and the discovery of new therapeutic targets through enrichment analysis and pivotal gene screening, as well as inferential analyses of related diagnostic efficacy and disease risk prediction.

Changepoint Detection with Outliers Based on RWPCA

Changepoint detection faces challenges when outlier data are present. This paper proposes a multivariate changepoint detection method which is based on the robust WPCA projection direction and the robust RFPOP method, RWPCA-RFPOP method. Our method is double robust which is suitable for detecting mean changepoints in multivariate normal data with high correlations between variables that include outliers. Simulation results demonstrate that our method provides strong guarantees on both the number and location of changepoints in the presence of outliers. Finally, our method is well applied in an ACGH dataset.

Impact of COVID-19 on liver transplant recipients: A nationwide cohort study evaluating hospitalization, transplant rejection, and inpatient mortality

BACKGROUND The coronavirus disease 2019(COVID-19)pandemic has posed a major public health concern worldwide.Patients with comorbid conditions are at risk of adverse outcomes following COVID-19.Solid organ transplant recipients with concurrent immunosuppression and comorbidities are more susceptible to a severe COVID-19 infection.It could lead to higher rates of inpatient complications and mortality in this patient population.However,studies on COVID-19 outcomes in liver transplant(LT)recipients have yielded inconsistent findings.AIM To evaluate the impact of the COVID-19 pandemic on hospital-related outcomes among LT recipients in the United States.METHODS We conducted a retrospective cohort study using the 2019–2020 National Inpatient Sample database.Patients with primary LT hospitalizations and a secondary COVID-19 diagnosis were identified using the International Classi-fication of Diseases,Tenth Revision coding system.The primary outcomes included trends in LT hospitalizations before and during the COVID-19 pandemic.Secondary outcomes included comparative trends in inpatient mortality and transplant rejection in LT recipients.RESULTS A total of 15720 hospitalized LT recipients were included.Approximately 0.8% of patients had a secondary diagnosis of COVID-19 infection.In both cohorts,the median admission age was 57 years.The linear trends for LT hospitalizations did not differ significantly before and during the pandemic(P=0.84).The frequency of in-hospital mortality for LT recipients increased from 1.7% to 4.4% between January 2019 and December 2020.Compared to the pre-pandemic period,a higher association was noted between LT recipients and in-hospital mortality during the pandemic,with an odds ratio(OR)of 1.69[95% confidence interval(CI):1.55-1.84),P<0.001].The frequency of transplant rejections among hospitalized LT recipients increased from 0.2%to 3.6% between January 2019 and December 2020.LT hospitalizations during the COVID-19 pandemic had a higher association with transplant rejection than before the pandemic[OR:1.53(95%CI:1.26-1.85),P<0.001].CONCLUSION The hospitalization rates for LT recipients were comparable before and during the pandemic.Inpatient mortality and transplant rejection rates for hospitalized LT recipients were increased during the COVID-19 pandemic.

Temperature Control of Proton Exchange Membrane Fuel Cell Based on Linear Active Disturbance Rejection Control

The performance of proton exchange membrane fuel cells is very sensitive to temperature. The electrochemical reaction results directly in temperature variations in the proton exchange membrane fuel cell. Ensuring effective temperature control is crucial to ensure fuel cell reliability and durability. This paper uses active disturbance rejection control in the thermal management system to maintain the operating temperature and the stack inlet and outlet temperature difference at the set value. First, key cooling system modules such as expansion tanks, coolant circulation pumps and radiators based on Simulink were built. Then, physical modeling and simulation of the fuel cell cooling system was carried out. In order to ensure the effectiveness of the control strategy and reduce the parameter tuning workload, an active disturbance rejection control parameter optimization method using an elite genetic algorithm was proposed. When the optimized control strategy responds to input disturbances, the maximum overshoot of the system is only 1.23% and can reach stability again in 30 s, so the fuel cell temperature can be controlled effectively. Simulation results show that the optimized control strategy can effectively control the stack temperature and coolant temperature difference under the influence of stepped charging current without interference or with interference, and has strong robustness and anti-interference capability.

Research on Grid-Connected Control Strategy of Distributed Generator Based on Improved Linear Active Disturbance Rejection Control

The virtual synchronous generator(VSG)technology has been proposed to address the problem of system frequency and active power oscillation caused by grid-connected new energy power sources.However,the traditional voltage-current double-closed-loop control used in VSG has the disadvantages of poor disturbance immunity and insufficient dynamic response.In light of the issues above,a virtual synchronous generator voltage outer-loop control strategy based on improved linear autonomous disturbance rejection control(ILADRC)is put forth for consideration.Firstly,an improved first-order linear self-immunity control structure is established for the characteristics of the voltage outer loop;then,the effects of two key control parameters-observer bandwidthω_(0)and controller bandwidthω_(c)on the control system are analyzed,and the key parameters of ILADRC are optimally tuned online using improved gray wolf optimizer-radial basis function(IGWO-RBF)neural network.A simulationmodel is developed using MATLAB to simulate,analyze,and compare the method introduced in this paper.Simulations are performed with the traditional control strategy for comparison,and the results demonstrate that the proposed control method offers superior anti-interference performance.It effectively addresses power and frequency oscillation issues and enhances the stability of the VSG during grid-connected operation.

W-band sharp-rejection bandpass filter with notch cavities

High-Q notch cavities combined with a low-order E-plane fin-line filter are used for designing a sharp-rejection band-pass filter （BPF） at W-band. Based on the conventional E-plane fin-line structure, an E-plane extended cavity is implemented to enhance the suppression at unwanted frequency points near the passband. The passband performance is not disturbed and the whole structure remains simple to be assembled. To extend the suppression bandwidth, two separated notch cavities are designed and arranged at the input and output ends of the fin-line filter, respectively. A prototype BPF is fabricated and measured. Experimental results show that the minimum insertion loss is 2.7 dB over a passband of 1 GHz. The suppression is about 85 dB near 91.7 GHz, which is 2.2 GHz lower than the center frequency. Experimental results agree well with simulation.

Recurrence and rejection in liver transplantation for primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic progressive inflammatory disease affecting the bile ducts, leading to f ibrosis and eventually cirrhosis in most patients. Its etiology is unknown and so far no effective medical therapy is available. Liver transplantation (LTX) is the only curative treatment and at present PSC is the main indication for LTX in the Scandinavian countries. Close to half of the PSC patients experience one or more episodes of acute cellular rejection (ACR) following transplantation and approximately 1/5 of the transplanted patients develop recurrent disease in the graft. In addition, some reports indicate that ACR early after LTX for PSC can infl uence the risk for recurrent disease. For these important post-transplantation entities affecting PSC patients, we have reviewed the current literature on epidemiology, pathogenesis, treatment and the possible infl uence of rejection on the risk of recurrent disease in the allograft.

Active disturbance rejection control on first-order plant

Conventional PI control encounters some problems when dealing with large lag process in the presence of parameter uncertainties.For the typical first-order process,an observerbased linear active disturbance rejection control（LADRC） scheme is presented to cope with the difficulties,and a reduced-order observer scheme is proposed further.Some quantitative dynamic results with regard to non-overshoot characteristics are obtained.Finally,the performance boundaries of LADRC and PI control are explicitly compared with each other,which shows that the former is more superior in most cases.

Markers of acute rejection and graft acceptance in liver transplantation

The evaluation of the immunosuppression state in liver transplanted patients is crucial for a correct posttransplant management and a major step towards the personalisation of the immunosuppressive therapy. However, current immunological monitoring after liver transplantation relies mainly on clinical judgment and on immunosuppressive drug levels, without a proper assessment of the real suppression of theimmunological system. Various markers have been studied in an attempt to identify a specific indicator of graft rejection and graft acceptance after liver transplantation. Considering acute rejection, the most studied markers are pro-inflammatory and immunoregulatory cytokines and other proteins related to inflammation. However there is considerable overlap with other conditions, and only few of them have been validated. Standard liver tests cannot be used as markers of graft rejection due to their low sensitivity and specificity and the weak correlation with the severity of histopathological findings. Several studies have been performed to identify biomarkers of tolerance in liver transplanted patients. Most of them are based on the analysis of peripheral blood samples and on the use of transcriptional profiling techniques. Amongst these, NK cell-related molecules seem to be the most valid marker of graft acceptance, whereas the role CD4+CD25+Foxp3+ T cells has still to be properly defined.

Interleukin-17 plays a critical role in the acute rejection of intestinal transplantation

AIM:To investigate the role of interleukin(IL)-17 in small bowel allograft rejection.METHODS:We detected the expression of helper T cell 17(Th17)cells in biopsy specimens from 3 cases of living small bowel transplantation in our department through immunofluorescence stain.We then established a rat heterotopic small bowel transplantation model.The rats were sacrificed on the 1st,2nd,3rd,5th, and 7th d after small bowel transplantation.The degrees of transplantation rejection in rat intestine graft were examined through hematoxylin eosin(HE)stain, and the expression of Th17 cells in rat intestine graft were detected through immunofluorescence stain. In addition,the recipient rats undergoing intestinal transplantation were administrated with mouse-anti-rat IL-17 monoclonal antibody(mAb),and the survival of rats was analyzed.The recipient rats which received mouse-anti-rat IL-17 mAb treatment were sacrificed on the 1st,2nd,3rd,5th,and 7th d after small bowel transplantation.The degrees of transplantation rejection and the expression of Th17 cells in rat intestine graft were detected through HE and immunofluorescence stain. The expression of IL-17,IL-1β,tumor necroses factor receptor-α(TNF-α),IL-6,and IL-8 in the intestine graft or serum were also detected. RESULTS:The expressions of Th17 cells ran parallel with the degree of acute rejection in human intestine grafts.The intestine graft rejection of rats was aggravated with prolonged duration after intestinal transplantation,and the expressions of Th17 cells were also correlated with the degree of acute rejection in rat intestine grafts.Administration of mouse-anti-rat IL-17 mAb prolonged the survival of rats after small bowel transplantation(P<0.001).Furthermore,we found that the administration of mouse-anti-rat IL-17 mAb significantly decreased the intensity of CD4+IL-17+Th17 cells in intestine grafts on the 2nd,3rd,5th,and the 7th d (97.22±4.05vs 12.45±2.02 on the 7th d,P<0.0001), and suppressed the severity of acute rejection.The expression of IL-17 in the intestine graft declined after mouse-anti-rat IL-17 mAb administration on the 2nd,3rd,5th,and the 7th d(0.88±0.03 vs 0.35±0.02 on the 7th d,P<0.0001).We also detected the IL-17 serum level and found that the IL-17 level reduced from the 1st d to the 7th d(6.52±0.18 ng/mL vs 2.04±0.15 ng/mL on the 7th d,P<0.0001).No significant difference in the level of IL-17 mRNA in the intestine graft was identified between the two groups.The levels of IL-1β,TNF-α, IL-6,and IL-8 mRNA in the intestine graft after the administration of mouse-anti-rat IL-17 mAb were also tested.We found that on the 3rd,5th,and 7th d after intestinal transplantation,administration of mouse-anti- rat IL-17 mAb significantly inhibited the levels of IL-1β (12.11±1.16 vs 1.27±0.15 on the 7th d,P<0.001), TNF-α(27.37±2.60 vs 1.06±0.26 on the 7th d,P< 0.001),IL-6(21.43±1.79 vs 1.90±0.32 on the 7th d, P<0.001),and IL-8(20.44±1.44 vs 1.34±0.20 on the 7th d,P<0.001)mRNA in the intestine graft. CONCLUSION:IL-17 may act as a promising and potent target for inhibiting acute rejection after small bowel transplantation.

The role of donor hepatocytes and/or splenocytes pre-injection in reducing islet xenotransplantation rejection

OBJECTIVE: To observe the effect of tail vein injection with donor hepatocyte and/or splenocyte on islets xenotransplantation rejection. METHODS: New-born male pigs and BALB/C mice were selected as donors and recipients respectively. Islets xenotransplantation was performed in recipients just after the third time of tail vein injection with donor hepatocytes and/or splenocytes. Macrophage phagocytosis, NK killing activity, T lymphocyte transforming function of spleen cells, antibody forming function of B lymphocytes, and T lymphocyte subsets were taken to monitor transplantation rejection. The effects of this kind of transplantation were indicated as variation of blood glucose and survival days of recipients. RESULTS: Streptozotocin (STZ) succeeded in inducing diabetes mellitus models of mice. Pre-injection of donor hepatocytes, and splenocytes or their mixture via tail vein was effective in preventing donor islets transplantation from rejection, which was demonstrated by the mentioned immunological marks. And each group of transplantation could decrease the blood glucose of recipients and prolong the survival days. Pre-injection of mixture of donor hepatocytes and splenocytes was more effective in preventing rejection than pre-injection of donor hepatocytes or splenocytes separately. CONCLUSION: We propose that pre-injection of donor hepatocytes, splenocytes separately or their mixture before donor islets transplantation is a good way to prevent rejection.

Outliers Mining in Time Series Data Sets

In this paper, we present a cluster-based algorithm for time series outlier mining.We use discrete Fourier transformation (DFT) to transform time series from time domain to frequency domain. Time series thus can be mapped as the points in k -dimensional space.For these points, a cluster-based algorithm is developed to mine the outliers from these points.The algorithm first partitions the input points into disjoint clusters and then prunes the clusters,through judgment that can not contain outliers.Our algorithm has been run in the electrical load time series of one steel enterprise and proved to be effective.

Chronic rejection after liver transplantation:Opening the Pandora’s box

Chronic rejection(CR)of liver allografts causes damage to intrahepatic vessels and bile ducts and may lead to graft failure after liver transplantation.Although its prevalence has declined steadily with the introduction of potent immunosuppressive therapy,CR still represents an important cause of graft injury,which might be irreversible,leading to graft loss requiring re-transplantation.To date,we still do not fully appreciate the mechanisms underlying this process.In addition to T cell-mediated CR,which was initially the only recognized type of CR,recently a new form of liver allograft CR,antibody-mediated CR,has been identified.This has indeed opened an era of thriving research and renewed interest in the field.Liver biopsy is needed for a definitive diagnosis of CR,but current research is aiming to identify new non-invasive tools for predicting patients at risk for CR after liver transplantation.Moreover,the minimization or withdrawal of immunosuppressive therapy might influence the establishment of subclinical CR-related injury,which should not be disregarded.Therapies for CR may only be effective in the“early”phases,and a tailored management of the immunosuppression regimen is essential for preventing irreversible liver damage.Herein,we provide an overview of the current knowledge and research on CR,focusing on early detection,identification of non-invasive biomarkers,immunosuppressive management,re-transplantation and future perspectives of CR.

Clinical factors affecting rejection rates in liver transplantation

With improvements in survival, liver trans- plant recipients now suffer more morbidity from long-term immunosuppression. Considerations were given to develop individualized immunosuppression based on their risk of re- jection. METHOD： We retrospectively analyzed the data of 788 liver transplants performed during the period from October 1991 to December 2011 to study the relationship between acute cel- lular rejection （ACR） and various clinical factors. RESULTS： Multivariate analysis showed that older age （P=0.04, OR=0.982）, chronic hepatitis B virus infection （P=0.005, OR= 0.574）, living donor liver transplantation （P=0.02, OR=0.648） and use of interleukin-2 receptor antagonist on induction （P〈0.001, OR=0.401） were associated with fewer ACRs. Patients with fulminant liver failure （P=.004, OR=4.05） were more likely to develop moderate to severe grade ACR. CONCLUSIONS： Liver transplant recipients with older age, chronic hepatitis B virus infection, living donor liver trans- plantation and use of interleukin-2 receptor antagonist on in- duction have fewer ACR. Patients transplanted for fulminant liver failure are at higher risk of moderate to severe grade ACR. These results provide theoretical framework for developing individualized immunosuppression.