Over the past decade, GPUs have demonstrated significant potential in accelerating Online Analytical Processing (OLAP) operations. However, there remains a substantial gap in their application to Online Transaction Processing (OLTP), as GPUs were traditionally considered unsuitable for such workloads. Despite this perception, the massive parallelism and high memory bandwidth of GPUs offer a unique opportunity to process thousands of transactions concurrently, making them promising candidates for OLTP acceleration. Concurrency control schemes, which play a critical role in determining the performance of OLTP systems, may behave differently on GPUs due to their architectural differences from CPUs. This raises a key question: How well do concurrency control schemes designed for CPUs adapt to GPU environments? To answer this, we present gCCTB, the first testbed designed to evaluate concurrency control schemes on GPUs. We implement and benchmark eight CC schemes, including six classic CPU-oriented schemes and two designed specifically for GPUs, on both the YCSB and TPC-C benchmarks under varied contention levels and GPU configurations. Our findings reveal that GPU-optimized schemes do not consistently outperform CPU-oriented schemes, particularly under specific workloads and contention levels. Moreover, GPU-specific parameters, such as the number of threads per warp and warps per block, significantly impact performance and require careful tuning. Finally, we find that conflict resolution overhead is a crucial factor influencing the performance of CPU-oriented schemes on GPUs, with optimistic concurrency control consistently minimizing this overhead and outperforming other CPU-oriented schemes across all workloads.

Query memory prediction is an essential yet underexplored problem in self-driving databases, particularly for high-concurrency workload scheduling where efficient resource utilization is critical. Existing works mainly focus on cost and latency estimation (e.g., using plan representation learning), while memory prediction poses new challenges such as requiring (1) numerous memory-specific training data, (2) memory-relevant query plan featurization strategies, and (3) a prediction model suitable for capturing the complexities of memory usage in query operations. Moreover, most learning-based approaches do not consider transferability across different datasets and database systems. This paper introduces Mem$Q$, a graph-based memory prediction framework designed for effective workload scheduling. First, we build a comprehensive training dataset for memory prediction by executing diverse query workloads across multiple datasets and recording their diverse peak memory consumptions. Second, our MemQ model leverages operator-level features of query plans, achieving high prediction accuracy, compact model size, and fast training and inference times. Third, we integrate the MemQ model into memory-aware First Fit Decreasing (FFD) and Bidrectional Fit (BF) scheduling strategy to optimize resource utilization. Extensive experiments demonstrate the effectiveness of our homogeneous query plan graph model. Moreover, our FFD scheduling strategy reduces makespan (total query execution time) by up to 55% and decreases retry counts by over 99% compared to default strategies when batch executing analytical queries on PostgreSQL. Furthermore, our novel BF strategy reduces makespan by 15.17% and reduces sum of total time by 41.41% compared with FFD strategy when batch executing mixed workloads.

Site recommendation, which aims at predicting the optimal location for brands to open new branches, has demonstrated an important role in assisting decision-making in modern business. In contrast to traditional recommender systems that can benefit from extensive information, site recommendation starkly suffers from extremely limited information and thus leads to unsatisfactory performance. Therefore, existing site recommendation methods primarily focus on several specific name brands and heavily rely on fine-grained human-crafted features to avoid the data sparsity problem. However, such solutions are not able to fulfill the demand for rapid development in modern business. Therefore, we aim to alleviate the data sparsity problem by effectively utilizing data across multiple cities and thereby propose a novel Optimal Transport enhanced Cross-city (OTC) framework for site recommendation. Specifically, OTC leverages optimal transport (OT) on the learned embeddings of brands and regions separately to project the brands and regions from the source city to the target city. Then, the projected embeddings of brands and regions are utilized to obtain the inference recommendation in the target city. By integrating the original recommendation and the inference recommendations from multiple cities, OTC is able to achieve enhanced recommendation results. The experimental results on the real-world OpenSiteRec dataset, encompassing thousands of brands and regions across four metropolises, demonstrate the effectiveness of our proposed OTC in further improving the performance of site recommendation models.

As a representative information retrieval task, site recommendation, which aims at predicting the optimal sites for a brand or an institution to open new branches in an automatic data-driven way, is beneficial and crucial for brand development in modern business. However, there is no publicly available dataset so far and most existing approaches are limited to an extremely small scope of brands, which seriously hinders the research on site recommendation. Therefore, we collect, construct and release an open comprehensive dataset, namely OpenSiteRec, to facilitate and promote the research on site recommendation. Specifically, OpenSiteRec leverages a heterogeneous graph schema to represent various types of real-world entities and relations in four international metropolises. To evaluate the performance of the existing general methods on the site recommendation task, we conduct benchmarking experiments of several representative recommendation models on OpenSiteRec. Furthermore, we also highlight the potential application directions to demonstrate the wide applicability of OpenSiteRec. We believe that our OpenSiteRec dataset is significant and anticipated to encourage the development of advanced methods for site recommendation. OpenSiteRec is available online at https://OpenSiteRec.github.io/.

The bursting of media sharing platforms like TikTok, YouTube, and Kwai enables normal users to create and share content with worldwide audiences. The most popular YouTuber can attract up to 100 million followers. Since there are multiple popular platforms, it’s quite common that a YouTuber publishes the same media to multiple platforms, or replicates all media from one platform to another. However, the users of different platforms have different tastes. The media that is popular on one platform may not be a great vogue on other platforms. Observing such cross-platform variance, we propose a new task: estimating the user engagement score of a media on one platform given its popularity on other platforms. This task can benefit both the YouTubers and the platform. On one hand, YouTubers can use the predicted engagement to guide the media reworking; on the other hand, the platform can use the predicted engagement to establish promotion and advertising plans. Therefore, this task is of great practical value. To tackle this task, we propose a disentangled neural network that can separate the general media adorability from platform inclinations. In this manner, by substituting the inclination from the source platform to the target platform, we are able to predict the user engagement in the target platform. To validate the proposed model, we manage to build a dataset of micro-videos which are published on four platforms TikTok, Kwai, Bilibili, and WESEE. The experimental results prove the effectiveness of the proposed model.

Accurate prediction of drug-drug interaction (DDI) is crucial to achieving effective decision-making in medical treatment for both doctors and patients. Recently, many deep learning based methods have been proposed to learn from drug-related features and conduct DDI prediction. These works have achieved promising results. However, the extreme imbalance of medical data poses a serious problem to DDI prediction, where a small fraction of DDI types occupy the majority training data. A straightforward way is to develop an appropriate policy to sample the data. Due to the high complexity and speciality of medical science, a dynamic learnable policy is required instead of a heuristic, uniform or static one. Therefore, we propose a REinforced Student-Teacher curriculum learning model (REST) for effective sampling to tackle this imbalance problem. Specifically, REST consists of two interactive parts, which are a heterogeneous graph neural network as the student and a reinforced sampler as the teacher. In each interaction, the teacher model takes action to sample an appropriate batch to train the student model according to the student model state while the cumulated improvement in performance of the student model is treated as the reward for policy gradient of the teacher model. The experimental results on two benchmarking datasets have demonstrated the significant effectiveness of our proposed model in DDI prediction, especially for the DDI types with low frequency.

The aim of ICD coding is to assign International Classification of Diseases (ICD) codes to unstructured clinical notes or discharge summaries. Numerous methods have been proposed for automatic ICD coding in an effort to reduce human labor and errors. However, existing works disregard the data imbalance problem of clinical notes. In addition, the noisy clinical note issue has not been thoroughly investigated. To address such issues, we propose a knowledge enhanced Graph Attention Network (GAT) under multi-task learning setting. Specifically, multi-level information transitions and interactions have been implemented. On the one hand, a large heterogeneous text graph is constructed to capture both intra- and inter-note correlations between various semantic concepts, thereby alleviating the data imbalance issue. On the other hand, two auxiliary healthcare tasks have been proposed to facilitate the sharing of information across tasks. Moreover, to tackle the issue of noisy clinical notes, we propose to utilize the rich structured knowledge facts and information provided by medical domain knowledge, thereby encouraging the model to focus on the clinical notes' noteworthy portion and valuable information. The experimental results on the widely-used medical dataset, MIMIC-III, demonstrate the advantages of our proposed framework.

Link prediction aims to identify potential missing triples in knowledge graphs. To get better results, some recent studies have introduced multimodal information to link prediction. However, these methods utilize multimodal information separately and neglect the complicated interaction between different modalities. In this paper, we aim at better modeling the inter-modality information and thus introduce a novel Interactive Multimodal Fusion (IMF) model to integrate knowledge from different modalities. To this end, we propose a two-stage multimodal fusion framework to preserve modality-specific knowledge as well as take advantage of the complementarity between different modalities. Instead of directly projecting different modalities into a unified space, our multimodal fusion module limits the representations of different modalities independent while leverages bilinear pooling for fusion and incorporates contrastive learning as additional constraints. Furthermore, the decision fusion module delivers the learned weighted average over the predictions of all modalities to better incorporate the complementarity of different modalities. Our approach has been demonstrated to be effective through empirical evaluations on several real-world datasets. The implementation code is available online at https://github.com/HestiaSky/IMF-Pytorch.

Structural graph clustering (SCAN) is a classic graph clustering algorithm. In SCAN, a key step is to compute the structural similarity between vertices according to the overlap ratio of one-hop neighborhoods. Given two vertices u and v, existing studies only consider the case when u and v are neighbors. However, the structural similarity between non-neighboring vertices in SCAN is always zero, and using only one-hop neighbors on weighted graphs discards the weights on each edge. Both may not reflect the true closeness of two vertices and may fail to return high-quality clustering results. To tackle this issue, we define and study the distance-based structural graph clustering problem. Given a distance threshold d and two vertices u and v, the structural similarity between u and v is defined as the ratio of their respective neighbors within a distance of no more than d. We show that the newly defined distance-based SCAN achieves better clustering results compared to the vanilla version of SCAN. However, the new definition brings challenges in the computation of final clustering results. To tackle this efficiency issue, we propose DistanceSCAN, an efficient approximate algorithm for solving the distance-based SCAN problem. The main idea of DistanceSCAN is to use all-distances bottom-k sketches (ADS) to speed up the computation of similarities. Given the ADS, we can derive the similarity between two vertices with a bounded cost of O(k). However, to ensure that the estimated similarity has an approximation guarantee, the value of k still needs to be set to as large as thousands. This brings high computational costs when computing the similarities between neighboring vertices. To tackle this issue, we further construct histograms to prune the structural similarity computations of vertices pairs. Extensive experiments on real datasets validate the effectiveness and efficiency of DistanceSCAN.

As a robust similarity measurement, Earth Mover's Distance (EMD) has been widely adopted in many real-world applications, such as machine learning, computer vision and natural language processing. In this paper, we study the problem of EMD-based similarity search, which aims at finding all histogram objects from a dataset whose EMD is within a pre-defined threshold from the given query. Since the time complexity of computing EMD is rather high, it is essential to devise effective techniques to accelerate the query processing. To this end, we propose a filter-and-verification framework: In the filter step, we devise three effective strategies to prune dissimilar objects in batch by sharing the computation between multiple objects. In the verification step, we develop novel flow adjustment techniques to incrementally calculate the EMD of candidates and enable early termination. We justify our proposed framework by conducting both theoretical analysis and extensive experiments. The results on four real world datasets show that our proposed techniques achieve up to an order of magnitude performance gain than state-of-the-art approaches.

Cross-Domain Recommendation (CDR) has attracted increasing attention in recent years as a solution to the data sparsity issue. The fundamental paradigm of prior efforts is to train a mapping function based on the overlapping users/items and then apply it to the knowledge transfer. However, due to the commercial privacy policy and the sensitivity of user data, it is unrealistic to explicitly share the user mapping relations and behavior data. Therefore, in this paper, we consider a more practical cross-domain scenario, where there is no explicit overlap between the source and target domains in terms of users/items. Since the user sets of both domains are drawn from the entire population, there may be commonalities between their user characteristics, resulting in comparable user preference distributions. Thus, without the mapping relations at user level, it is feasible to model this distribution-level relation to transfer knowledge between domains. To this end, we propose a novel framework that improves the effect of representation learning on the target domain by aligning the representation distributions between the source and target domains. In addition, GWCDR can be easily integrated with existing single-domain collaborative filtering methods to achieve cross-domain recommendation. Extensive experiments on two pairs of public bidirectional datasets demonstrate the effectiveness of our proposed framework in enhancing the recommendation performance.

As a robust similarity measurement, Earth Mover's Distance (EMD) has been widely adopted in many real-world applications, such as machine learning, computer vision and natural language processing. In this paper, we study the problem of EMD-based similarity search, which aims at finding all histogram objects from a dataset whose EMD is within a pre-defined threshold from the given query. Since the time complexity of computing EMD is rather high, it is essential to devise effective techniques to accelerate the query processing. To this end, we propose a filter-and-verification framework: In the filter step, we devise effective strategies to prune dissimilar objects in batch by sharing the computation between multiple objects. In the verification step, we develop novel flow adjustment techniques to incrementally calculate the EMD of candidates and enable early termination. We justify our proposed framework by conducting both theoretical analysis and extensive experiments. The results on four real world datasets show that our proposed techniques achieve up to an order of magnitude performance gain than state-of-the-art approaches.

Click-Through Rate (CTR) prediction, estimating the probability of a user clicking on items, plays a key fundamental role in sponsored search. E-commerce platforms display organic search results and advertisements (ads), collectively called items, together as a mixed list. The items displayed around the predicted ad, i.e. external items, may affect the user clicking on the predicted. Previous CTR models assume the user click only relies on the ad itself, which overlooks the effects of external items, referred to as external effects, or externalities. During the advertising prediction, the organic results have been generated by the organic system, while the final displayed ads on multiple ad slots have not been figured out, which leads to two challenges: 1) the predicted (target) ad may win any ad slot, bringing about diverse externalities. 2) external ads are undetermined, resulting in incomplete externalities. Facing the above challenges, inspired by the Transformer, we propose EXternality TRansformer (EXTR) which regards target ad with all slots as query and external items as key&value to model externalities in all exposure situations in parallel. Furthermore, we design a Potential Allocation Generator (PAG) for EXTR, to learn the allocation of potential external ads to complete the externalities. Extensive experimental results on Alibaba datasets demonstrate the effectiveness of externalities in the task of CTR prediction and illustrate that our proposed approach can bring significant profits to the real-world e-commerce platform. EXTR now has been successfully deployed in the online search advertising system in Alibaba, serving the main traffic.

Among diverse parts in database systems, database prefetching, which aims at predicting future page access patterns and fetching pages to be accessed ahead of time to mitigate blocked I/O operations, plays a crucial role in the overall performance tuning. Existing approaches just use simple heuristic-based methods and suffer from the low hit rate and extra I/O overhead. Recently, with the emerging success of machine learning in different applications, attempts using learning-based models to augment or improve components for database systems have shed some light on this tough problem. Impressed by the enormous potential of machine learning in data management, we present an end-to-end deep learning-based framework to predict page access patterns. We model the prediction of page access as a classification problem and evaluate several variants of neural networks on the accuracy of prediction. On the basis of it, we propose a new Multi-Model framework to construct an accurate model for prefetching. On a suite of real-world database benchmarks, our neural network based prefetching model consistently outperforms existing widely used solutions in real-world database systems.

Online social networking companies devote much effort to maximize the engagement of users. Most existing methods assume that the budget is already known and focus on heuristic solutions to maximize the number of users that keep engaged. However, many real-life applications aim to keep the engagement of the majority of users in the social network. In such scenarios, the budget is flexible, and the goal is to minimize the budget used to keep these users active. In this paper, we define and study the anchored k-core budget minimization problem. Given an undirected graph G, a degree constraint k and a quota q for engaged users, this problem aims to minimize the budget that assures at least q users not in k-core keeping engaged.We propose CLOCK, an efficient greedy algorithm to solve the anchored k-core budget minimization problem. The main idea is to delete the anchored vertex with the lowest score in every iteration while maintaining the required number of engaged users. By considering the influence among the anchored vertices, a scoring function is well designed to identify the anchored vertices with high quality. Then we propose two merging strategies to get better anchored vertices. In addition, we dynamically maintain all anchored vertices by a local update strategy which avoids many redundant calculations. Finally, we conduct extensive experiments on real world datasets, demonstrating the effectiveness and efficiency of CLOCK.

Index plays an essential role in modern database engines to accelerate the query processing. The new paradigm of "learned index" has significantly changed the way of designing index structures in DBMS. The key insight is that indexes could be regarded as learned models that predict the position of a lookup key in the dataset. While such studies show promising results in both lookup time and index size, they cannot efficiently support update operations. Although recent studies have proposed some preliminary approaches to support update, they are at the cost of scarifying the lookup performance as they suffer from the overheads brought by imprecise predictions in the leaf nodes. In this paper, we propose LIPP, a brand new framework of learned index to address such issues. Similar with state-of-the-art learned index structures, LIPP is able to support all kinds of index operations, namely lookup query, range query, insert, delete, update and bulkload. Meanwhile, we overcome the limitations of previous studies by properly extending the tree structure when dealing with update operations so as to eliminate the deviation of location predicted by the models in the leaf nodes. Moreover, we further propose a dynamic adjustment strategy to ensure that the height of the tree index is tightly bounded and provide comprehensive theoretical analysis to illustrate it. We conduct an extensive set of experiments on several real-life and synthetic datasets. The results demonstrate that our method consistently outperforms state-of-the-art solutions, achieving by up to 4X for a broader class of workloads with different index operations.

Set similarity search is a fundamental operation in a variety of applications [3] , [5] , [2] . There is a long stream of research on the problem of set similarity search. Given a collection of set records, a query and a similarity function, the algorithm will return all the set records that are similarity with the query. There are many metrics to measure the similarity between two sets, such as Overlap, Jaccard, Cosine and Dice. In this paper we use the widely applied Jaccard to quantify the similarity between two sets, but our proposed techniques can be easily extended to other set-based similarity functions. Previous approaches require users to specify a threshold of similarity. However, in many scenarios it is rather difficult to specify such a threshold. For example, when users types some keywords in the search engine, they will pay more attention for the results which rank in the front, say the top five ones. In this case, if we use threshold-based search instead of KNN similarity search, it is difficult to find the results that are more attractive for users.

Knowledge graphs have been widely adopted to improve recommendation accuracy. The multi-hop user-item connections on knowledge graphs also endow reasoning about why an item is recommended. However, reasoning on paths is a complex combinatorial optimization problem. Traditional recommendation methods usually adopt brute-force methods to find feasible paths, which results in issues related to convergence and explainability. In this paper, we address these issues by better supervising the path finding process. The key idea is to extract imperfect path demonstrations with minimum labeling efforts and effectively leverage these demonstrations to guide path finding. In particular, we design a demonstration-based knowledge graph reasoning framework for explainable recommendation. We also propose an ADversarial Actor-Critic (ADAC) model for the demonstration-guided path finding. Experiments on three real-world benchmarks show that our method converges more quickly than the state-of-the-art baseline and achieves better recommendation accuracy and explainability.

Health knowledge graph provides an ideal technical means to integrate heterogeneous data resources and enhance knowledge-based services. There are many challenges for the construction of health knowledge graph such as complex concepts and relationships, various medical standards, heterogeneous data structures, poor data quality, highly accurate and interpretable services, etc. In this paper, firstly, we propose Health Knowledge Graph Builder (HKGB), an end-to-end platform which could be used to construct disease-specific and extensible health knowledge graphs from multiple sources. Secondly, we analyze the capabilities and requirements of clinicians, design the tasks to involve the clinicians and implement a clinician-in-the-loop toolset to integrate the clinicians prior knowledge into the construction of health knowledge graphs. Thirdly, we design an extensible mechanism to add new diseases to an existing knowledge graph. Fourthly, we present a quantitative effort estimation algorithm to quantitatively evaluate the effort of clinicians during the construction, and use it to calculate the workloads such as 44.27 person days for knee osteoarthritis domain. Finally, we have developed several knowledge graph based tools to facilitate real applications.

Set similarity search is a fundamental operation in a variety of applications. While many previous studies focus on threshold based set similarity search and join, few efforts have been paid for KNN set similarity search. In this paper, we propose a transformation based framework to solve the problem of KNN set similarity search, which given a collection of set records and a query set, returns k results with the largest similarity to the query. We devise an effective transformation mechanism to transform sets with various lengths to fixed length vectors which can map similar sets closer to each other. Then, we index such vectors with a tiny tree structure. Next, we propose efficient search algorithms and pruning strategies to perform exact KNN set similarity search. We also design an estimation technique by leveraging the data distribution to support approximate KNN search, which can speed up the search while retaining high recall. Experimental results on real world datasets show that our framework significantly outperforms state-of-the-art methods in both memory and disk based settings.

Given two collections of objects, metric similarity join finds all similar pairs of objects according to a particular distance function in metric space. There is an increasing demand to provide a scalable similarity join algorithm which can support efficient query and analytical services in the era of Big Data. In this paper, we propose SMS-Join, a parallel framework to support similarity join in metric space based on the MapReduce paradigm. The overall workflow of SMS-Join is that it first finds some records as pivots in the preprocessing phase and then splits the data into partitions based on them with a map job. Finally the join results are obtained via a reduce job. To ensure load balancing between the partitions, we devise a light-weighted sampling technique to obtain high quality samples while maintaining the high performance. To reduce the partition cost, we develop an iterative partition strategy in the map phase. We implement our framework upon Apache Spark platform and conduct extensive experiments on four real world datasets. The results show that our method significantly outperforms state-of-the-art methods.

Location-aware services have become widely available on a variety of devices. The resulting fusion of spatio-textual data enables the kind of top-k query that takes into account both location proximity and text relevance. Considering both the misspellings in user input and the data quality issues of spatiotextual databases, it is necessary to support error-tolerant spatial keyword search for end-users. Existing studies mainly focused on set-based textual relevance, but they cannot find reasonable results when the input tokens are not exactly matched with those from records in the database. In this paper, we propose a novel framework to solve the problem of top-k location-aware similarity search with fuzzy token matching. We propose a hierarchical index HGR-Tree to capture signatures of both spatial and textual relevance. Based on such an index structure, we devise a best-first search algorithm to preferentially access nodes of HGR-Tree with more similar objects while those with dissimilar ones can be pruned. We further devise an incremental search strategy to reduce the overhead brought by supporting fuzzy token matching. Experimental results on real world POI datasets show that our framework outperforms state-of-the-art methods by one to two orders of magnitude.

Stock trend prediction, aiming at predicting future price trend of stocks, plays a key role in seeking maximized profit from the stock investment. Recent years have witnessed increasing efforts in applying machine learning techniques, especially deep learning, to pursue more promising stock prediction. While deep learning has given rise to significant improvement, human investors still retain the leading position due to their understanding on stock intrinsic properties, which can imply invaluable principles for stock prediction. In this paper, we propose to extract and explore stock intrinsic properties to enhance stock trend prediction. Fortunately, we discover that the repositories of investment behaviors within mutual fund portfolio data form up a gold mine to extract latent representations of stock properties, since such collective investment behaviors can reflect the professional fund managers' common beliefs on stock intrinsic properties. Powered by extracted stock properties, we further propose to model the dynamic market state and trend using stock representations so as to generate the dynamic correlation between the stock and the market, and then we aggregate such correlation with dynamic stock indicators to achieve more accurate stock prediction. Extensive experiments on real-world stock market data demonstrate the effectiveness of stock properties extracted from collective investment behaviors in the task of stock prediction.

Digging rich knowledge from clinical texts becomes a popular topic today. Knowledge graph has been widely used to integrate and manage abundant knowledge. Entity recognition and relation extraction play important roles in constructing knowledge graphs. In this paper, we develop a system to recognize entities and extract their relations from clinical texts in Electronic Medical Records. Our system implements four major functions: manual entity annotation, automatic entity recognition, manual relation annotation and automatic relation extraction. Tools of entity annotation and relation annotation are designed for professionals to help them manually annotate objects given original clinical texts. Moreover, entity recognition and relation recognition, which CRF and CNN are applied in, are accessible for professionals before manual annotation in order to increase the efficiency. Our system has been used in several applications, such as medical knowledge graph construction and health QA system.

Massive Electronic Medical Records (EMRs) contain a lot of knowledge and Named Entity Recognition (NER) in Chinese EMR is a very important task. However, due to the lack of Chinese medical dictionary, there are few studies on NER in Chinese EMR. In this paper, we first build a medical dictionary. We then investigated the effects of different types of features in Chinese clinical NER tasks based on Condition Random Fields (CRF) algorithm, the most popular algorithm for NER, including bag-of-characters, part of speech, dictionary feature, and word clustering features. In the experimental section, we randomly selected 220 clinical texts from Peking Anzhen Hospital. The experimental results showed that these features were beneficial in varying degrees to Chinese named entity recognition. Finally, after analyzing the experimental results, we get some rules of thumb.

The Global Positioning System(GPS) is used to find a specific point on the real earth although GPS positioning technology is becoming more and more mature, GPS always exists with equipment inherent errors or measurement methods errors. so map matching step is a very important preprocessing for lots of applications, such as traffic flow control, taxi mileage calculation, and finding some people. However, many current methods only deal with distance variables and do not handle angle variables between two segments. In this paper, we propose a new road network map matching algorithm, considering not only the distance between two sample points but also taking into account the angle between two candidate segments using the Hidden Markov Model (HMM) which is a popular solution for map matching. Subsequently, to solve the HMM problem, we make use of dynamic programming Viterbi algorithm to find the maximum probability road segments. The experiments are implemented on BEIJING CITY map real dataset and display that our map matching algorithm significantly improve the accuracy compared with ST-Matching global algorithm.

Similarity search is an essential operation in many applications. Given a collection of set records and a query, the exact set similarity search aims at finding all the records that are similar to the query from the collection. Existing methods adopt a filter-and-verify framework, which make use of inverted indexes. However, as the complexity of verification is rather low for setbased similarity metrics, they always fail to make a good tradeoff between filter power and filter cost. In this paper, we proposed an efficient framework for exact set similarity search based on tree index structure. We defined a hash-based ordering to effectively import data into the index structure and then make optimizations to reduce the filter cost. To further improve the filter power, we proposed a dynamic algorithm to partition the dataset into several parts and propose a multiple-index framework. Experimental results on real-world datasets show that our method significantly outperform the state-of-the-art algorithms.

In recent years, with the development of high-throughput technologies and the increase of omics data, molecular diagnostics and the analysis of patients' exact causative genes become possible. However, massive data also challenges traditional methods. GWAS(Genome-Wide Association Study) traditional methods are usually used for causative gene discovery of single-gene disorders. But because they needs to do statistical test and analysis to each SNP loci; High-throughput genomic data show that there are usually millions of such SNP(Single Nucleotide Polymorphism) loci, so it may take longer times and more resources to discover the exact causative genes of patients. In this regard, we use a prediction strategy which integrates the knowledge of both bioinformatics and complex networks to discover the exact causative gene from given candidate genes. The strategy is: first, build a protein interaction network and choose the core disease gene; second, calculate similarities between candidate genes and core gene for each patient; third, sort the similarity of each patient in descending order, so that the top-ranking genes are the potential causative genes. Based on the above policy, local, semi-local, global indicators are compared in this paper. In addition, the paper also proposes a similarity index based on asymmetric similarity. Experimental results show that taking into account the asymmetry interaction for selecting different core gene, the new method based on asymmetric similarity achieved the best discovery result, which also proves the effectiveness of the new method.

Social influence occurs when one’s opinions, emotions, or behaviors are affected by others in a social network. However, social influence takes many forms, and its underlying mechanism is still unclear. For example, how is one’s behavior influenced by a group of friends who know each other and by the friends from different ego friend circles? In this article, we study the social influence problem in a large microblogging network. Particularly, we consider users’ (re)tweet behaviors and focus on investigating how friends in one’s ego network influence retweet behaviors. We propose a novel notion of social influence locality and develop two instantiation functions based on pairwise influence and structural diversity. The defined influence locality functions have strong predictive power. Without any additional features, we can obtain an F1-score of 71.65% for predicting users’ retweet behaviors by training a logistic regression classifier based on the defined influence locality functions. We incorporate social influence locality into a factor graph model, which can further leverage the network-based correlation. Our experiments on the large microblogging network show that the model significantly improves the precision of retweet prediction. Our analysis also reveals several intriguing discoveries. For example, if you have six friends retweeting a microblog, the average likelihood that you will also retweet it strongly depends on the structure among the six friends: The likelihood will significantly drop (only ⅙) when the six friends do not know each other, compared with the case when the six friends know each other.

We study the problem of active learning for networked data, where samples are connected with links and their labels are correlated with each other. We particularly focus on the setting of using the probabilistic graphical model to model the networked data, due to its effectiveness in capturing the dependency between labels of linked samples. We propose a novel idea of connecting the graphical model to the information diffusion process, and precisely define the active learning problem based on the non-progressive diffusion model. We show the NP-hardness of the problem and propose a method called MaxCo to solve it. We derive the lower bound for the optimal solution for the active learning setting, and develop an iterative greedy algorithm with provable approximation guarantees. We also theoretically prove the convergence and correctness of MaxCo.

For the massive remote image file's management, we build the file catalog system of data application based on the part whole ontology of spatial relation. The method is that we analyzed the attributed item of image metadata and calculated the weight for application, then build the catalog concept level relation, calculated the similitude degree of the image attributed item and catalogue node to build the catalog system, stored the file into the corresponding directory of catalog. We design and realize the catalog system, the experiment show that the method of data integration based on the subdivision of part whole ontology is effective for image data's high efficient integrative management.

We propose a dual hash tables algorithm which can realize the durable top-k search. Two hash tables are constructed to keep the core information, such as score and time in the inverted lists. We use the key-value relationships between the two hash tables to calculate the scores which measure the correlations between a keyword and documents, and search the versioned objects that are consistent in the top-k results throughout a given query interval. Finally, we use data from Wikipedia to demonstrate the efficiency and performance of our algorithm.

Hybrid row-column storage model [1][4], a common database approach for both OLTP and OLAP, have attracted a lot of attention in the past few years. Previous works about hybrid row-column approach mainly focus on physical storage. In this paper, we propose the idea of Layout-Conscious Optimization(LCO), techniques that fully exploits possibilities and take advantages of hybrid row-column data layout in all layers of DBMS, e.g., physical storage, query processing as well as network transfer. We believe LCO offer new opportunities to improve the performance of DBMS. To demonstrate the power of LCO, we present the design of a row-column hybrid network transfer protocol for DBMS, which reduces data transfer by 75% while incurs little extra cost on CPU.

With the development of cloud computing technologies, big data processing is becoming more and more important. How to mine and analyze massive data is facing a very big challenge. In this paper, we proposed an efficient massive data mining and analysis framework Data Cloud on large clusters. The most important part of Data Cloud is the Rabbit. It is a kind of massive data mining and analysis processing plan framework on the large clusters like the Pig and Hive. We make a detail analysis about the Rabbit plan.

Link prediction is an important problem in social network mining. Traditional neighborhood based methods such as Common neighbors, Jaccard Coefficient and Adamic/Adar are well studied in link prediction. However, the concept of structural holes does not receive significant attention in link prediction. As a preliminary work in studying structural holes, we focus on bipartite social networks, which is a special class of social networks that consists of two distinct roles for the users, and links are between users of different roles. In this study, a few implementations of structural holes are proposed, which are then validated with extended neighborhood based methods on a real dataset derived from IMDb network. The results show that structural holes help in improving accuracies in link prediction.

Massive rules processing has attracted more attention in recently years. Firstly, we propose a rule description language that can express all kind of rules by structured nature language. We design a set of graphical symbols for rule nodes. We also propose a rule traffic flow model and a rule cost model. Thought these models, it is easier to process massive numbers rules and optimize them.

Collaborative filtering has been very successful in both research and applications such as information filtering and E-commerce. The k-Nearest Neighbor (KNN) method is a popular way for its realization. Its key technique is to find k nearest neighbors for a given user to predict his interests. However, this method suffers from two fundamental problems: sparsity and scalability. In this paper, we present our solutions for these two problems. We adopt two techniques: a matrix conversion method for similarity measure and an instance selection method. And then we present an improved collaborative filtering algorithm based on these two methods. In contrast with existing collaborative algorithms, our method shows its satisfactory accuracy and performance.