Similar Neighbors Research Articles

Point Cloud Registration Method Based on Geometric Constraint and Transformation Evaluation.

Existing point-to-point registration methods often suffer from inaccuracies caused by erroneous matches and noisy correspondences, leading to significant decreases in registration accuracy and efficiency. To address these challenges, this paper presents a new coarse registration method based on a geometric constraint and a matrix evaluation. Compared to traditional registration methods that require a minimum of three correspondences to complete the registration, the proposed method only requires two correspondences to generate a transformation matrix. Additionally, by using geometric constraints to select out high-quality correspondences and evaluating the matrix, we greatly increase the likelihood of finding the optimal result. In the proposed method, we first employ a combination of descriptors and keypoint detection techniques to generate initial correspondences. Next, we utilize the nearest neighbor similarity ratio (NNSR) to select high-quality correspondences. Subsequently, we evaluate the quality of these correspondences using rigidity constraints and salient points' distance constraints, favoring higher-scoring correspondences. For each selected correspondence pair, we compute the rotation and translation matrix based on their centroids and local reference frames. With the transformation matrices of the source and target point clouds known, we deduce the transformation matrix of the source point cloud in reverse. To identify the best-transformed point cloud, we propose an evaluation method based on the overlap ratio and inliers points. Through parameter experiments, we investigate the performance of the proposed method under various parameter settings. By conducting comparative experiments, we verified that the proposed method's geometric constraints, evaluation methods, and transformation matrix computation consistently outperformed other methods in terms of root mean square error (RMSE) values. Additionally, we validated that our chosen combination for generating initial correspondences outperforms other descriptor and keypoint detection combinations in terms of the registration result accuracy. Furthermore, we compared our method with several feature-matching registration methods, and the results demonstrate the superior accuracy of our approach. Ultimately, by testing the proposed method on various types of point cloud datasets, we convincingly established its effectiveness. Based on the evaluation and selection of correspondences and the registration result's quality, our proposed method offers a solution with fewer iterations and higher accuracy.

A similarity-based assortativity measure for complex networks

Abstract There are several metrics that have been proposed to quantify the tendency of nodes to link with similar nodes in complex networks. Among them, the assortativity coefficient put forth by M.E.J. Newman has been successfully used in many cases with either categorical or scalar attributes of network nodes. Unfortunately, the assortativity coefficient cannot deal with vectorial attributes. Furthermore, we show that, in certain cases, it may not be able to capture the similarity of neighbors. In this work, we introduce a new metric that, without being much more complex to calculate, solves those problems. Moreover, we show that the proposed metric includes the categorical assortativity coefficient as a particular case. We also study the behavior of the new metric with a few illustrative real-world examples.

Image Regression With Structure Cycle Consistency for Heterogeneous Change Detection.

Change detection (CD) between heterogeneous images is an increasingly interesting topic in remote sensing. The different imaging mechanisms lead to the failure of homogeneous CD methods on heterogeneous images. To address this challenge, we propose a structure cycle consistency-based image regression method, which consists of two components: the exploration of structure representation and the structure-based regression. We first construct a similarity relationship-based graph to capture the structure information of image; here, a k -selection strategy and an adaptive-weighted distance metric are employed to connect each node with its truly similar neighbors. Then, we conduct the structure-based regression with this adaptively learned graph. More specifically, we transform one image to the domain of the other image via the structure cycle consistency, which yields three types of constraints: forward transformation term, cycle transformation term, and sparse regularization term. Noteworthy, it is not a traditional pixel value-based image regression, but an image structure regression, i.e., it requires the transformed image to have the same structure as the original image. Finally, change extraction can be achieved accurately by directly comparing the transformed and original images. Experiments conducted on different real datasets show the excellent performance of the proposed method. The source code of the proposed method will be made available at https://github.com/yulisun/AGSCC.

Identification of Critical Links Based on Electrical Betweenness and Neighborhood Similarity in Cyber-Physical Power Systems.

Identifying critical links is of great importance for ensuring the safety of the cyber-physical power system. Traditional electrical betweenness only considers power flow distribution on the link itself, while ignoring the local influence of neighborhood links and the coupled reaction of information flow on energy flow. An identification method based on electrical betweenness centrality and neighborhood similarity is proposed to consider the internal power flow dynamic influence existing in multi-neighborhood nodes and the topological structure interdependence between power nodes and communication nodes. Firstly, for the power network, the electrical topological overlap is proposed to quantify the vulnerability of the links. This approach comprehensively considers the local contribution of neighborhood nodes, power transmission characteristics, generator capacity, and load. Secondly, in communication networks, effective distance closeness centrality is defined to evaluate the importance of communication links, simultaneously taking into account factors such as the information equipment function and spatial relationships. Next, under the influence of coupled factors, a comprehensive model is constructed based on the dependency relationships between information flow and energy flow to more accurately assess the critical links in the power network. Finally, the simulation results show the effectiveness of the proposed method under dynamic and static attacks.

DRGCL: Drug Repositioning via Semantic-enriched Graph Contrastive Learning.

Drug repositioning greatly reduces drug development costs and time by discovering new indications for existing drugs. With the development of technology and large-scale biological databases, computational drug repositioning has increasingly attracted remarkable attention, which can narrow down repositioning candidates. Recently, graph neural networks (GNNs) have been widely used and achieved promising results in drug repositioning. However, the existing GNNs based methods usually focus on modeling the complex drug-disease association graph, but ignore the semantic information on the graph, which may lead to a lack of consistency of global topology information and local semantic information for the learned features. To alleviate the above challenge, we propose a novel drug repositioning model based on graph contrastive learning, termed DRGCL. First, we treat the known drug-disease associations as the topology graph. Second, we select the top- K similar neighbor from drug/disease similarity information to construct the semantic graph rather than use the traditional data augmentation strategy, thereby maximally retaining rich semantic information. Finally, we pull closer to embedding consistency of the different embedding spaces by graph contrastive learning to enhance the topology and semantic feature on the graph. We have evaluated DRGCL on four benchmark datasets and the experiment results show that the proposed DRGCL is superior to the state-of-the-art methods. Especially, the average result of DRGCL is 11.92% higher than that of the second-best method in terms of AUPRC. The case studies further demonstrate the reliability of DRGCL. Experimental datasets and experimental codes can be found in https://github.com/Jiaxiao123/DRGCL.

A Malicious Information Traceability Model Based on Neighborhood Similarity and Multiple Types of Interaction

A Malicious Information Traceability Model Based on Neighborhood Similarity and Multiple Types of Interaction

Denoised Graph Collaborative Filtering via Neighborhood Similarity and Dynamic Thresholding

Denoised Graph Collaborative Filtering via Neighborhood Similarity and Dynamic Thresholding

A Dual-Modality Complex-Valued Fusion Method for Predicting Side Effects of Drug-Drug Interactions Based on Graph Neural Network.

Predicting potential side effects of drug-drug interactions (DDIs), which is a major concern in clinical treatment, can increase therapeutic efficacy. In recent studies, how to use the multi-modal drug features is important for DDI prediction. Thus, it remains a challenge to explore an efficient computational method to achieve the feature fusion cross- and intra-modality. In this paper, we propose a dual-modality complex-valued fusion method (DMCF-DDI) for predicting the side effects of DDIs, using the form and properties of complex-vector to enhance the representations of DDIs. Firstly, DMCF-DDI applies two Graph Convolutional Network (GCN) encoders to learn molecular structure and topological features from fingerprint and knowledge graphs, respectively. Secondly, an asymmetric skip connection (ASC) uses distinct semantic-level features to construct the complex-valued drug pair representations (DPRs). Then, the complex-vector multiplication is used as a fusion operator to obtain the fine-grained DPRs. Finally, we calculate the prediction probability of DDIs by Hermitian inner product in the complex space. Compared with other methods, DMCF-DDI achieves superior performance in all situations using a fusion operator with the lowest parameter numbers. For the case study, we select six diseases and common side effects in clinical treatment to verify identification ability of our model. We also prove the advantage of ASC and complex-valued fusion can achieve to align the cross-modal fused positive DPRs through a comprehensive analysis on the phase-modulus distribution histogram of DPRs. In the end, we explain the reason for alignment based on the similarity of features and node neighbors.

Context Matters: Distilling Knowledge Graph for Enhanced Object Detection

The human visual system is capable of not only recognizing individual objects but also comprehending the contextual relationship between them in real-world scenarios, making it highly advantageous for object detection. However, in practical applications, such contextual information is often not available. Previous attempts to compensate for this by utilizing cross-modal data such as language and statistics to obtain contextual priors have been deemed sub-optimal due to a semantic gap. To overcome this challenge, we present a seamless integration of context into an object detector through Knowledge Distillation. Our approach intuitively represents context as a knowledge graph, describing the relative location and semantic relevance of different visual concepts. Leveraging recent advancements in graph representation learning with Transformer, we exploit the contextual information among objects using edge encoding and graph attention. Specifically, each image region propagates and aggregates the representation from its highly similar neighbors to form the knowledge graph in the Transformer encoder. Extensive experiments and a thorough ablation study conducted on challenging benchmarks MS-COCO, Pascal VOC and LVIS demonstrate the superiority of our method.

Self-Training Algorithm With Block Similar Neighbor Editing

Self-Training Algorithm With Block Similar Neighbor Editing

Dopcc: Detecting overlapping protein complexes via multi-metrics and co-core attachment method.

Identification of protein complex is an important issue in the field of system biology, which is crucial to understanding the cellular organization and inferring protein functions. Recently, many computational methods have been proposed to detect protein complexes from protein-protein interaction (PPI) networks. However, most of these methods only focus on local information of proteins in the PPI network, which are easily affected by the noise in the PPI network. Meanwhile, it's still challenging to detect protein complexes, especially for overlapping cases. To address these issues, we propose a new method, named Dopcc, to detect overlapping protein complexes by constructing a multi-metrics network according to different strategies. First, we adopt the Jaccard coefficient to measure the neighbor similarity between proteins and denoise the PPI network. Then, we propose a new strategy, integrating hierarchical compressing with network embedding, to capture the high-order structural similarity between proteins. Further, a new co-core attachment strategy is proposed to detect overlapping protein complexes from multi-metrics. The experimental results show that our proposed method, Dopcc, outperforms the other eight state-of-the-art methods in terms of F-measure, MMR, and Composite Score on two yeast datasets. The source code and datasets can be downloaded from https://github.com/CSUBioGroup/Dopcc.

Deep Feature-Based Neighbor Similarity Hashing With Adversarial Learning for Cross-Modal Retrieval

Deep Feature-Based Neighbor Similarity Hashing With Adversarial Learning for Cross-Modal Retrieval

Multiple kernel clustering with local kernel reconstruction and global heat diffusion

Multiple Kernel Clustering (MKC) is an effective approach for revealing nonlinear cluster structures in candidate kernels. However, existing MKC methods still face two key challenges. Firstly, the pairwise affinity in these methods is primarily determined by kernel similarity, disregarding the correlations among highly similar neighbors and resulting in redundant weight assignments and reduced clustering discriminability. Secondly, the direct utilization of affinity matrices overlooks high-order connections and introduces noise due to independent row-wise solving. To address these issues, we propose a novel local MKC method called LKRGDF. We begin by exploring affinity using the Local Kernel Reconstruction (LKR) model, reducing redundancy and enhancing clustering discriminability. Furthermore, we exploit the affinities with the Global heat kernel Diffusion (GD) procedure to capture long-range connections smoothly. The GD process acts as a low pass filter, focusing on small eigenvalues corresponding to top clusters. Finally, we integrate these smooth affinities within an auto-weighted Multiple Graph Fusion (MGF) framework to obtain a consensus graph. By assembling LKR, GD, and MGF in a sequential pipeline, our approach achieves the exploration and exploitation of local structures, gradually improving clustering performance while ensuring computational efficiency without the need for iterative steps. Extensive experiments on ten datasets demonstrate the superiority of our algorithm in terms of effectiveness and efficiency compared to state-of-the-art methods. The code for our method is publicly available at https://github.com/YanChenSCU/LKRGDF-2023.git.

3D-CNN and semi-supervised based network for hyperspectral unmixing

ABSTRACT Hyperspectral Unmixing (HU), which involves decomposing mixed pixels in hyperspectral images into endmembers and abundance fractions, plays a critical role in spectral analysis. Recent advancements in deep learning methods have shown successful applications in hyperspectral analysis. This paper proposes an end-to-end network structure that combines a Convolutional Neural Network (CNN) and a Multilayer Perceptron (MLP). The 3D-CNN extracts high-level features from both spatial and spectral neighbourhoods of hyperspectral image patches, while the MLP maps these abstracted features to abundance fractions. Considering the challenge of acquiring manual labels, we adopt a Semi-Supervised learning approach that leverages unlabelled data to enhance training. We divide our training data into labelled and unlabelled subsets, defining distinct loss functions for each. Additionally, we introduce a neighbourhood similarity constraint to fully exploit spatial context information. To address scenarios where no labelled data is available, we employ Generative Adversarial Networks (GANs) to generate synthetic labelled samples. Experimental evaluations conducted on both synthetic and real datasets validate the effectiveness of our proposed method, which outperforms several commonly used and state-of-the-art HU methods.

A CODE model bridging crowding in sparse and dense displays

Visual crowding is arguably the strongest limitation imposed on extrafoveal vision, and is a relatively well-understood phenomenon. However, most investigations and theories are based on sparse displays consisting of a target and at most a handful of flanker objects. Recent findings suggest that the laws thought to govern crowding may not hold for densely cluttered displays, and that grouping and nearest neighbour effects may be more important. Here we present a computational model that accounts for crowding effects in both sparse and dense displays. The model is an adaptation and extension of an earlier model that has previously successfully accounted for spatial clustering, numerosity and object-based attention phenomena. Our model combines grouping by proximity and similarity with a nearest neighbour rule, and defines crowding as the extent to which target and flankers fail to segment. We show that when the model is optimized for explaining crowding phenomena in classic, sparse displays, it also does a good job in capturing novel crowding patterns in dense displays, in both existing and new data sets. The model thus ties together different principles governing crowding, specifically Bouma’s law, grouping, and nearest neighbour similarity effects.

Shared neighbors rough set model and neighborhood classifiers

Neighborhood relations are established by employing a distance metric and parameters, where the distance metric is utilized to measure the dissimilarities between objects. The information about adjacent objects tends to vary, even though these objects belong to a neighborhood. Taking into account neighborhood information, this paper introduces a similarity measure of shared neighbors, which is determined by the overlapping neighbors in a neighborhood relation. The similarity measure, induced by a neighborhood relation, is superior to the distance metric in quantifying differences, and it is crucial to note that the neighborhood relation can be any binary relation. A neighborhood of shared neighbors is proposed based on the proposed similarity measure, which consists of the most similar neighbors. Subsequently, we propose the shared neighbors rough set model, which is regarded as a framework of fusing neighborhood information. Moreover, an attribute reduction algorithm and a neighborhood classifier of shared neighbors are designed. The experimental results demonstrate the effectiveness of the neighborhood classifier and the shared neighbors rough set model.

STGNet: Short‐term residential load forecasting with spatial–temporal gated fusion network

AbstractWith the continuous transformation of the global power system, ensuring the flexibility and stability of the power system has become a direction that the global energy industry has been striving for. This puts forward higher requirements for load forecasting, especially high‐precision short‐term residential load forecasting. However, the high volatility and uncertainty of electric consumption make this problem challenging. Existing methods usually focus on capturing temporal correlations and ignore the underlying spatial correlations in historical loads, which is crucial for accurate forecasting. In this paper, we propose a novel spatial–temporal gated fusion network (STGNet) for short‐term residential load forecasting including not only individual residential load but also aggregated load. By seeking both adaptive neighbors and temporal similarity neighbors, we construct a dynamic graph based on a data‐driven method. On this basis, we provide an adaptive graph gated fusion mechanism to capture fine‐grained node‐specific spatial dependence more accurately and comprehensively. Finally, a bidirectional gated recurrent unit (BiGRU) is utilized to learn the temporal dependence of load data. Extensive experiments on real‐world datasets are conducted and demonstrate the superiority of STGNet over the existing approaches.

Mapping cultural ecosystem services in mountain forests using mobile phone data

The aim of the work was to determine the spatial distribution of activity in the forest on the area of the Forest Promotional Complex “Sudety Zachodnie” using mobile phone data. The study identified the sites with the highest (hot spot) and lowest (cold spot) use. Habitat, stand, demographic, topographic and spatial factors affecting the distribution of activity were also analyzed. Two approaches were applied in our research: global and local Moran’s coefficients, and a machine learning technique, Boosted Regression Trees. The results show that 11,503,320 visits to forest areas were recorded in the “Sudety Zachodnie” in 2019. The most popular season for activities was winter, and the least popular was spring. Using global and local Moran’s I coefficients, three small hot clusters of activity and one large cold cluster were identified. Locations with high values with similar neighbours (hot-spots) were most often visited forest areas, averaging almost 200,000 visits over 2019. Significantly fewer visits were recorded in cold-spots, the average number of visits to these areas was about 4,500. The value of global Moran’s I was equal to 0.54 and proved significant positive spatial autocorrelation. Results of Boosted Regression Trees modeling of visits in forest, using tree stand habitat and spatial factors accurately explained 76% of randomly selected input data. The variables that had the greatest effect on the distribution of activities were the density of hiking and biking trails and diversity of topography. The methodology presented in this article allows delineation of Cultural Ecosystem Services hot spots in forest areas based on mobile phone data. It also allows the identification of factors that may influence the distribution of visits in forests. Such data are important for managing forest areas and adapting forest management to the needs of society while maintaining ecosystem stability.

A Neighborhood-Similarity-Based Imputation Algorithm for Healthcare Data Sets: A Comparative Study

The increasing computerisation of medical services has highlighted inconsistencies in the way in which patients’ historic medical data were recorded. Differences in process and practice between medical services and facilities have led to many incomplete and inaccurate medical histories being recorded. To create a single point of truth going forward, it is necessary to correct these inconsistencies. A common way to do this has been to use imputation techniques to predict missing data values based on the known values in the data set. In this paper, we propose a neighborhood similarity measure-based imputation technique and analyze its achieved prediction accuracy in comparison with a number of traditional imputation methods using both an incomplete anonymized diabetes medical data set and a number of simulated data sets as the sources of our data. The aim is to determine whether any improvement could be made in the accuracy of predicting a diabetes diagnosis using the known outcomes of the diabetes patients’ data set. The obtained results have proven the effectiveness of our proposed approach compared to other state-of-the-art single-pass imputation techniques.

On the difficulty of validating molecular generative models realistically: a case study on public and proprietary data

While a multitude of deep generative models have recently emerged there exists no best practice for their practically relevant validation. On the one hand, novel de novo-generated molecules cannot be refuted by retrospective validation (so that this type of validation is biased); but on the other hand prospective validation is expensive and then often biased by the human selection process. In this case study, we frame retrospective validation as the ability to mimic human drug design, by answering the following question: Can a generative model trained on early-stage project compounds generate middle/late-stage compounds de novo? To this end, we used experimental data that contains the elapsed time of a synthetic expansion following hit identification from five public (where the time series was pre-processed to better reflect realistic synthetic expansions) and six in-house project datasets, and used REINVENT as a widely adopted RNN-based generative model. After splitting the dataset and training REINVENT on early-stage compounds, we found that rediscovery of middle/late-stage compounds was much higher in public projects (at 1.60%, 0.64%, and 0.21% of the top 100, 500, and 5000 scored generated compounds) than in in-house projects (where the values were 0.00%, 0.03%, and 0.04%, respectively). Similarly, average single nearest neighbour similarity between early- and middle/late-stage compounds in public projects was higher between active compounds than inactive compounds; however, for in-house projects the converse was true, which makes rediscovery (if so desired) more difficult. We hence show that the generative model recovers very few middle/late-stage compounds from real-world drug discovery projects, highlighting the fundamental difference between purely algorithmic design and drug discovery as a real-world process. Evaluating de novo compound design approaches appears, based on the current study, difficult or even impossible to do retrospectively.Scientific Contribution This contribution hence illustrates aspects of evaluating the performance of generative models in a real-world setting which have not been extensively described previously and which hopefully contribute to their further future development.