Modern vehicle navigation systems can greatly benefit from waypoint point-of-interest (POI) recommendation, which suggests personalized intermediate stops along a driving route. This paper defines the novel waypoint POI recommendation problem: given a starting point and a destination, recommend one or more personalized POIs to visit en route. This scenario (e.g., suggesting a lunch stop during a road trip) differs from the conventional ''next POI'' recommendation in that it infers waypoint POIs from only two (origin and destination) inputs and predicts multiple intermediate stops rather than a single next location. To solve this problem, we propose WayPOI, a novel recommender model for Waypoint POI suggestion based on hierarchical graph based contrastive learning (WayPOI). WayPOI constructs a hierarchical graph that captures both individual and group-level behavioral patterns of users and POIs, and it employs a contrastive learning strategy to learn effective user and POI representations from sparse data. Through experiments on real-world driving data provided by Hyundai as well as on three public datasets, we demonstrate that WayPOI significantly outperforms several recent POI recommendation models, even though these baselines were carefully re-formed and retrained to perform waypoint recommendation for a fair comparison. Our ablation study confirms the benefit of each proposed component.

Test-Time Adaptation (TTA) aims to adapt an unseen target domain utilizing the unlabeled target data using a pre-trained source model. Continual TTA is a more challenging paradigm that deals with non-stationary environments during the test data adaptation. Most existing continual TTA methods are based on pseudo-labeling, but often (1) rely on overconfident pseudo-labels and (2) remain unstable under continual distribution shifts leading to error accumulation and catastrophic forgetting. To tackle these limitations, we propose Neighbor-Filtration based Continual Test-Time Adaptation (NF-CTTA), a reliable and memory-aware adaptation framework that addresses these challenges. NF-CTTA first calibrates pseudo-labels using class-conditional calibration error to correct over/under-confidence of the model. To further ensure reliability, we introduce an OOD Neighbor Filtration technique that selects a subset of high-confidence samples based on entropy and neighbor similarity, ensuring consistency within the semantic neighborhood. Finally, we propose a priority-guided memory buffer that retains the most informative low-entropy samples for replay, mitigating catastrophic forgetting across evolving test distributions. Extensive experiments across multiple domain shift benchmarks demonstrate that NF-CTTA achieves superior performance and stability compared to existing TTA and CTTA methods. The code is available at: https://github.com/takihasan/NF-CTTA.

Beyond the traditional CNN structure, we have recently witnessed lots of breakthroughs in computer vision architectures such as Vision Transformer, MLP-Mixer, SNN-MLP, and so on. However, many efforts in developing novel architectures for vision tasks are heavily focused on achieving powerful performances, and how to attain interpretability in a trained neural network remains an open question. Inspired by the imaginary system GLOM, we present HiLite : Hierarchical Level-implemented Architecture attaining Part-Whole Interpretability, where islands of identical vectors can provide unprecedented interpretability. In our column-like structure, each level is a layer of a part-whole hierarchy composed of multiple neurons, and the function to define the neural field along an image input patch is initialized as the level vector inside the model. We propose two-column networks (Top-Down (TD) and Bottom-Up (BU)) that allow inter-level communication between adjacent levels on a specific patch and propose Gated Consensus Attention to perform intra-level communication on different patches within the level. At each time step, the level vector and outputs from different networks are combined into a weighted sum and passed to the next step, and outputs from the final time step are utilized as representation vectors. Here, supervised contrastive learning is used to find the relationship of meaningful patches in each class, where negative examples contribute to preventing representation collapse between neighboring patches. HiLite shows a possibility of performance through a quantitative evaluation on four image classification datasets as well as two metrics for assessing representation quality and showcases the intrinsic interpretability by simply generating a visual cue. We believe that our work is a solid step towards novel research on neural architectures attaining interpretability.

Deep Neural Networks (DNNs) tend to perform poorly on unseen domains due to domain shifts. Domain Generalization (DG) aims to improve the performance on such scenarios by minimizing the distribution discrepancy between source domains. Among many studies, dropout-based DG approaches which remove domain-specific features have gained attention. However, they are limited in minimizing the upper bound of generalization risk because they do not explicitly consider the distribution discrepancy when discarding features. In this paper, we propose a novel Discrepancy-guided Channel Dropout (DgCD) for DG that explicitly derives the discrepancy between domains and drops the channels with significant distribution discrepancy. Given a training batch, we perform two ways of standardization: (1) based on the variance/mean of the batch (i.e., sampled from all source domains) and (2) based on the variance/mean of domain-wise samples in the batch. With the two normal distributions, we explicitly derive the discrepancy using KL-divergence and backpropagate it towards each channel. A channel with a higher contribution to the discrepancy is more likely to be dropped. Experimental results show the superiority of DgCD over the state-of-the-art DG baselines, demonstrating the effectiveness of our dropout strategy which is directly coupled to reducing the domain discrepancy. Our code is available at: https://github.com/gyeomo/DgCD

Hypergraphs are effective in learning high-order relationships between nodes, which naturally represent group interactions as hyperedges (i.e., arbitrary-sized subsets of nodes). However, most approaches currently used for learning hypergraph representations do not consider pairwise relationships between nodes. While high-order relationships provide insight into the general connections among nodes in a group, they do not reveal the pairwise relationships between individual nodes within that group. Considering that it is unlikely for all nodes in the same group to share identical relationships, we argue that considering pairwise relationships is a critical aspect. In this paper, we propose Multi-view Mixed Attention for Contrastive Learning (MMACL) to address the aforementioned problem. MMACL proposes Mixed-Attention, which blends high-order relationships derived from the hypergraph attention network and pairwise relationships derived from the graph attention network. Then, it performs node-level contrastive learning to the graph structure with different views learned at each layer to finally obtain an expressive node representation. Our extensive experimental results on several popular datasets validate the effectiveness of the proposed MMACL for hypergraph node classification. Our code is available at: https://github.com/JongsooLee-HYU/MMACL

Recently, Graph Neural Networks (GNNs) have achieved state-of-the-art performance on the multivariate time-series anomaly detection task by learning relationships between variables (sensors). However, they show limitations in capturing temporal dependencies due to lack of sufficient consideration on the characteristics of time to their graph structure. Several studies constructed a time-oriented graph, where each node represents a timestamp within a certain sliding window, to model temporal dependencies, but they failed to learn the trend of changes in time-series. This paper proposes Dual time-oriented Graph ATtention networks (DuoGAT) that resolves the aforementioned problems. Unlike previous work that uses the simple complete undirected structure for time-oriented graphs, our work models directed graphs with weighted edges that only connect from prior events to posterior events, and the edges that connect nearby events are given higher weights. In addition, another time-oriented graph is used to model time series stationary via differencing, which especially focuses on capturing the series of changes. Empirically, our method outperformed the existing state-of-the-art work with the highest F1-score for the four real-world dataset while maintaining low training cost. We also proposed a novel explanation method for anomaly detection using DuoGAT, which provides time-oriented reasoning via hierarchically tracking time points critical in a specific anomaly detection. Our code is available at: https://github.com/ByeongtaePark/DuoGAT

Time-series forecasting has been actively studied and adopted in various real-world domains. Recently there have been two research mainstreams in this area: building Transformer-based architectures such as Informer, Autoformer and Reformer, and developing time-series representation learning frameworks based on contrastive learning such as TS2Vec and CoST. Both efforts have greatly improved the performance of time series forecasting. In this paper, we investigate a novel direction towards improving the forecasting performance even more, which is orthogonal to the aforementioned mainstreams as a model-agnostic scheme. We focus on time stamp embeddings that has been less-focused in the literature. Our idea is simple-yet-effective: based on given current time stamp, we predict embeddings of its near future time stamp and utilize the predicted embeddings in the time-series (value) forecasting task. We believe that if such future time information can be previewed at the time of prediction, they can be utilized by any time-series forecasting models as useful additional information. Our experimental results confirmed that our method consistently and significantly improves the accuracy of the recent Transformer-based models and time-series representation learning frameworks. Our code is available at: https://github.com/sunsunmin/Look_Ahead

Collaborative Filtering (CF) methods for recommender systems commonly suffer from the data sparsity issue. Data imputation has been widely adopted to deal with this issue. However, existing studies have limitations in the sense that both uncertainty and robustness of imputation have not been taken into account, where there is a high risk that the imputed values are likely to be far from the true values. This paper explores a novel imputation framework, named Uncertainty-Aware Multiple Imputation (UA-MI), which can effectively solve the sparsity issue. Given a (sparse) user-item interaction matrix, our key idea is to quantify uncertainty on each missing entry and then the cells with the lowest uncertainty are selectively imputed. Here, we suggest three strategies for measuring uncertainty in missing user-item interactions, each of which is based on sampling, dropout, and ensemble, respectively. They successfully obtain element-wise mean and variance on the missing entries, where the variance helps determine where in the matrix should be imputed and the corresponding mean values are imputed. Experiments show that our UA-MI framework significantly outperformed the existing imputation strategies

This paper focuses on the problem of forecasting daily traffic of new roads, where very little data is available for prediction. We propose a novel prediction model based on Generative Adversarial Networks (GAN) that learns the subtle patterns of the changes in the traffic flow according to the various contextual factors. Then the trained generator makes a prediction via generating a realistic traffic flow data of a target new road given its weather and day type. Both the quantitative and qualitative results of our extensive experiments indicate the effectiveness of our method.

Triangular meshes have been actively used in computer graphics to represent 3D shapes. However, due to their non-uniform and irregular nature, learning such data with a Deep Neural Network is not straightforward. Transforming mesh data to simpler structures (e.g., voxel grids, point clouds, or multi-view 2D images) leads to other issues including spatial information loss and scalability. Traditional descriptors for mesh data simply extract hand-crafted features, which might not be effective in various environments. Several deep architectures that directly consume mesh data have been proposed, but their input features are still heuristic and unable to fully capture both geodesic and geometric characteristics of a mesh. In addition, their model architectures are not designed to be capable of providing visual explanations of their decision making.

Explainable recommendation has gained great attention in recent years. A lot of work in this research line has chosen to use the knowledge graphs (KG) where relations between entities can serve as explanations. However, existing studies have not considered sentiment on relations in KG, although there can be various types of sentiment on relations worth considering (e.g., a user's satisfaction on an item). In this paper, we propose a novel recommendation framework based on KG integrated with sentiment analysis for more accurate recommendation as well as more convincing explanations. To this end, we first construct a Sentiment-Aware Knowledge Graph (namely, SAKG) by analyzing reviews and ratings on items given by users. Then, we perform item recommendation and reasoning over SAKG through our proposed Sentiment-Aware Policy Learning (namely, SAPL) based on a reinforcement learning strategy. To enhance the explainability for end-users, we further developed an interactive user interface presenting textual explanations as well as a collection of reviews related with the discovered sentiment. Experimental results on three real-world datasets verified clear improvements on both the accuracy of recommendation and the quality of explanations.

For these few decades malwares have been posing a major concern in the cyber security. Recently, a number of "author groups" have been generating lots of newmalwares by sharing source code within a group and exploiting evasive schemes such as polymorphism and metamorphism. This motivates us to study the problem of identifying the author group of a given malware, which would be able to work for not only blocking malwares but also legally punishing suspected malware authors. In this paper, we propose a human-machine collaborative approach for classifying author groups of malwares accurately. We also propose a visualization method for helping human experts to make the decision easily. We verify the superiority of our framework through extensive experiments using real-world malware data.

Cold-start problems are arguably the biggest challenges faced by collaborative filtering (CF) used in recommender systems. When few ratings are available, CF models typically fail to provide satisfactory recommendations for cold-start users or to display cold-start items on users' top-N recommendation lists. Data imputation has been a popular choice to deal with such problems in the context of CF, filling empty ratings with inferred scores. Different from (and complementary to) data imputation, this paper presents AR-CF, which stands for Augmented Reality CF, a novel framework for addressing the cold-start problems by generating virtual, but plausible neighbors for cold-start users or items and augmenting them to the rating matrix as additional information for CF models. Notably, AR-CF not only directly tackles the cold-start problems, but is also effective in improving overall recommendation qualities. Via extensive experiments on real-world datasets, AR-CF is shown to (1) significantly improve the accuracy of recommendation for cold-start users, (2) provide a meaningful number of the cold-start items to display in top-N lists of users, and (3) achieve the best accuracy as well in the basic top-N recommendations, all of which are compared with recent state-of-the-art methods.

Generative Adversarial Networks (GAN) have not only achieved a big success in various generation tasks such as images, but also boosted the accuracy of classification tasks by generating additional labeled data, which is called data augmentation. In this paper, we propose a Rating Augmentation framework with GAN, named RAGAN, aiming to alleviate the data sparsity problem in collaborative filtering (CF), eventually improving recommendation accuracy significantly. We identify a unique challenge that arises when applying GAN to CF for rating augmentation: naive RAGAN tends to generate values biased towards high ratings. Then, we propose a refined version of RAGAN, named RAGANBT, which addresses this challenge successfully. Via our extensive experiments, we validate that our RAGANBT is really effective to solve the data sparsity problem, thereby providing existing CF models with great improvement in accuracy under various situations such as basic top-N recommendation, long-tail item recommendation, and recommendation to cold-start users.

Generative Adversarial Networks (GAN) have achieved big success in various domains such as image generation, music generation, and natural language generation. In this paper, we propose a novel GAN-based collaborative filtering (CF) framework to provide higher accuracy in recommendation. We first identify a fundamental problem of existing GAN-based methods in CF and highlight it quantitatively via a series of experiments. Next, we suggest a new direction of vector-wise adversarial training to solve the problem and propose our GAN-based CF framework, called CFGAN, based on the direction. We identify a unique challenge that arises when vector-wise adversarial training is employed in CF. We then propose three CF methods realized on top of our CFGAN that are able to address the challenge. Finally, via extensive experiments on real-world datasets, we validate that vector-wise adversarial training employed in CFGAN is really effective to solve the problem of existing GAN-based CF methods. Furthermore, we demonstrate that our proposed CF methods on CFGAN provide recommendation accuracy consistently and universally higher than those of the state-of-the-art recommenders.

This paper proposes a novel birthmark, a dynamic API authority vector (DAAV), for detecting software theft. DAAV satisfies four essential requirements for good birthmarks--credibility, resiliency, scalability, and packing-free--while existing birthmarks fail to satisfy all of them together. In particular, existing static birthmarks are unable to handle the packed programs and existing dynamic birthmarks do not satisfy credibility and resiliency. Our experimental results demonstrate that DAAV provides satisfying credibility and resiliency compared with existing dynamic birthmarks and also can cover packed programs.

As plagiarism of software increases rapidly, there are growing needs for software plagiarism detection systems. In this paper, we propose a software plagiarism detection system using an API-labeled control flow graph (A-CFG) that abstracts the functionalities of a program. The A-CFG can reflect both the sequence and the frequency of APIs, while previous work rarely considers both of them together. To perform a scalable comparison of a pair of A-CFGs, we use random walk with restart (RWR) that computes an importance score for each node in a graph. By the RWR, we can generate a single score vector for an A-CFG and can also compare A-CFGs by comparing their score vectors. Extensive evaluations on a set of Windows applications demonstrate the effectiveness and the scalability of our proposed system compared with existing methods.