Numerous Pattern Recognition Research Articles

Specific-sized Hyaluronan Fragments Promote Expression of Human β-Defensin 2 in Intestinal Epithelium

Hyaluronan (HA) is a glycosaminoglycan polymer found in the extracellular matrix of virtually all mammalian tissues. Recent work has suggested a role for small, fragmented HA polymers in initiating innate defense responses in immune cells, endothelium, and epidermis through interaction with innate molecular pattern recognition receptors, such as TLR4. Despite these advances, little is known regarding the effect of fragmented HA at the intestinal epithelium, where numerous pattern recognition receptors act as sentinels of an innate defense response that maintains epithelial barrier integrity in the presence of abundant and diverse microbial challenges. Here we report that HA fragments promote expression of the innate antimicrobial peptide human β-defensin 2 (HβD2) in intestinal epithelial cells. Treatment of HT-29 colonic epithelial cells with HA fragment preparations resulted in time- and dose-dependent up-regulated expression of HβD2 protein in a fragment size-specific manner, with 35-kDa HA fragment preparations emerging as the most potent inducers of intracellular HβD2. Furthermore, oral administration of specific-sized HA fragments promotes the expression of an HβD2 ortholog in the colonic epithelium of both wild-type and CD44-deficient mice but not in TLR4-deficient mice. Together, our observations suggest that a highly size-specific, TLR4-dependent, innate defense response to fragmented HA contributes to intestinal epithelium barrier defense through the induction of intracellular HβD2 protein.

Virally Infected Mouse Liver Endothelial Cells Trigger CD8 + T-Cell Immunity

Dendritic cell activation through ligation of pattern recognition receptors leading to full functional maturation causes induction of CD8(+) T-cell immunity through increased delivery of costimulatory signals instead of tolerance. Here we investigate whether organ-resident antigen-presenting cells, such as liver sinusoidal endothelial cells (LSECs), also switch from tolerogenic to immunogenic CD8(+) T-cell activation upon such stimulation. Murine LSECs were isolated by immunomagnetic separation and analyzed for functional maturation upon triggering pattern recognition receptors or viral infection employing gene expression analysis and T cell coculture assays. In vivo relevance of the findings was confirmed with bone-marrow chimeric animals. LSECs expressed numerous pattern recognition receptors that allowed for sentinel function, but ligand-induced activation of these receptors was not sufficient to overcome tolerance induction of CD8(+) T cells. Importantly, viral infection with murine cytomegalovirus caused functional maturation of antigen-presenting LSECs and was sufficient to promote antigen-specific differentiation into effector CD8(+) T cells in the absence of dendritic cells and independent of CD80/86. These results shed new light on the generation of organ-specific immunity and may contribute to overcoming tolerance in relevant situations, such as cancer.

Antiviral immunotherapy: emerging approaches with relevance to cutaneous disease

Recent developments in the characterization of the receptors and pathways of the innate immune system, and of the mechanisms of activation of adaptive immunity, have opened new possibilities for modulation of the immune response to eradicate neoplasms and to overcome resistant viral infections. The discovery of numerous and varied pattern recognition receptors and their ligands have helped to explain the success of older therapies, and paved the way for the novel immunomodulator, imiquimod, which demonstrates the practical applicability of immunomodulation to cutaneous disease. In this review we summarize current knowledge on the mechanisms of activation of innate immunity to viral disease, available therapies and agents in development for cutaneous antiviral immunomodulation, and the implications of the current restructuring of the understanding of cell-mediated immunity, the desired end point of innate immunomodulation, on future immunomodulatory modalities.

Analysis of Two-Dimensional Non-Rigid Shapes

Analysis of deformable two-dimensional shapes is an important problem, encountered in numerous pattern recognition, computer vision and computer graphics applications. In this paper, we address three major problems in the analysis of non-rigid shapes: similarity, partial similarity, and correspondence. We present an axiomatic construction of similarity criteria for deformation-invariant shape comparison, based on intrinsic geometric properties of the shapes, and show that such criteria are related to the Gromov-Hausdorff distance. Next, we extend the problem of similarity computation to shapes which have similar parts but are dissimilar when considered as a whole, and present a construction of set-valued distances, based on the notion of Pareto optimality. Finally, we show that the correspondence between non-rigid shapes can be obtained as a byproduct of the non-rigid similarity problem. As a numerical framework, we use the generalized multidimensional scaling (GMDS) method, which is the numerical core of the three problems addressed in this paper.

Organizing Gaussian mixture models into a tree for scaling up speaker retrieval

Numerous pattern recognition tasks set in the probabilistic framework face the following issue: it is expensive to evaluate the likelihood function for test data, when there are given very many candidate probabilistic models for explaining this data. We consider the application of this general and important problem to speaker recognition for indexing and retrieval purposes in radio archives. More precisely, we propose to reduce complexity at query time, by prior organization of speaker models into a hierarchy. This is very classically done for multi-dimensional vectors, but we propose herein a technique for building a hierarchy of probabilistic models, in the case these models take the form of a Gaussian mixture. From a closed-form approximation of Kullback–Leibler divergence between parent and children, an optimality criterion and an optimization technique are derived, from which we propose an efficient approach for building a tree of models, using clustering techniques (dendrogram-based or k-means-like). The proposed scheme is evaluated on real data.

Dectin‐1 promotes fungicidal activity of human neutrophils

Human polymorphonuclear leukocytes (PMN) are a first line of defense against fungal infections. PMN express numerous pattern recognition receptors (PRR) that facilitate identification of invading microorganisms and ultimately promote resolution of disease. Dectin-1 (beta-glucan receptor) is a PRR expressed on several cell types and has been studied on monocytes and macrophages. However, the role played by dectin-1 in the recognition and killing of fungi by PMN is unknown. We investigated the ability of dectin-1 to mediate human PMN phagocytosis and fungicidal activity. Dectin-1 was expressed on the surface of PMN from all subjects tested (n=29) and in an intracellular compartment that co-sedimented with azurophilic granules in Percoll density gradients. Soluble beta-glucan and mAb GE2 (anti-dectin-1) inhibited binding and phagocytosis of zymosan by human PMN (e.g., ingestion was inhibited 40.1% by 30 min, p<0.001), and blocked reactive oxygen species production. Notably, soluble beta-glucan and GE2 inhibited phagocytosis and killing of Candida albicans by PMN (inhibition of killing was 54.8% for beta-glucan and 36.2% for GE2, p<0.01). Our results reveal a mechanism whereby PMN dectin-1 plays a key role in the recognition and killing of fungal pathogens by the innate immune system.

BWIM 시스템을 사용한 사장교의 차량하중 분석

본 논문에서는 교량 모니터링 시스템의 일부분으로 서해대교에 설치된 교량 하중측정 시스템(BWIM system)으로부터 획득한 신호를 분석하여 통행차량의 정보를 추출하기 위한 알고리즘의 개발과정과 이를 위해 수행한 현장 차량주행시험에 대하여 기술하였다. 개발된 BWIM 시스템은 포장층에 매설하는 축감지기가 없는 형태로, 바닥판과 가로보에 설치된 변형률계로부터 측정한 시간이력 변형률신호만을 이용하였다. 이들 측정신호로부터 추출하고자 하는 차량의 정보는 통과차로, 통과속도, 차 축수 및 총 중량이며, 이들 정보의 추출을 위해 패턴인식기법의 일종인 인공신경망(Aritificial Neural Network, ANN) 기법을 사용하였다. 현장 차량주행시험을 통하여 기지차량 및 미지차량 통행시의 BWIM 응답 데이터를 측정하였으며, 이들 실측데이터를 사용하여 인공신경망의 학습 및 성능검증을 수행하였다. 개발된 기법을 사용하여 추출되는 차량의 정보들은 현재의 교량상태 및 피로수명 평가시 활용될 수 있을 것이며, 향후 설계트럭 하중모델의 개정시 기초자료로도 활용될 수 있을 것으로 기대된다. This paper describes the procedures developing the algorithm for analyzing signals acquired from the Bridge Weigh-in-Motion (BWIM) system installed in Seohae Bridge as a part of the bridge monitoring system. Through the analysis procedure, information about heavy traffics such as weight, speed, and number of axles are attempted to be extracted from time domain strain data of the BWIM system. One of numerous pattern recognition techniques, artificial neural network (ANN) is employed since it can effectively include dynamic effects, bridge-vehicle interaction, etc. A number of vehicle running experiments with sufficient load cases are executed to acquire training and/or test set of ANN. Extracted traffic information can be utilized for developing quantitative database of loading effect. Also, it can contribute to estimate fatigue lift or current health condition, and design truck can be revised based on the database reflecting recent trend of traffic.

Genetic-based search for error-correcting graph isomorphism

Error-correcting graph isomorphism has been found useful in numerous pattern recognition applications. This paper presents a genetic-based search approach that adopts genetic algorithms as the searching criteria to solve the problem of error-correcting graph isomorphism. By applying genetic algorithms, some local search strategies are amalgamated to improve convergence speed. Besides, a selection operator is proposed to prevent premature convergence. The proposed approach has been implemented to verify its validity. Experimental results reveal the superiority of this new technique than several other well-known algorithms.

Accuracy and space bandwidth in space variant optical correlators

Numerous space variant optical pattern recognition systems using coordinate transformations have been reported recently. In this paper, we consider the required space bandwidth of these systems and the resultant accuracy of these novel deformation invariant correlators.