Geo-textual Data Research Articles

Privacy Preserving Publish/Subscribe for Geo-Textual Data Streams

Privacy Preserving Publish/Subscribe for Geo-Textual Data Streams

RASK: Range Spatial Keyword Queries on Massive Encrypted Geo-Textual Data

RASK: Range Spatial Keyword Queries on Massive Encrypted Geo-Textual Data

DLRD: dual-level network for rumor detection on geo-textual data

DLRD: dual-level network for rumor detection on geo-textual data

WISK: A Workload-aware Learned Index for Spatial Keyword Queries

Spatial objects often come with textual information, such as Points of Interest (POIs) with their descriptions, which are referred to as geo-textual data. To retrieve such data, spatial keyword queries that take into account both spatial proximity and textual relevance have been extensively studied. Existing indexes designed for spatial keyword queries are mostly built based on the geo-textual data without considering the distribution of queries already received. However, previous studies have shown that utilizing the known query distribution can improve the index structure for future query processing. In this paper, we propose WISK, a learned index for spatial keyword queries, which self-adapts for optimizing querying costs given a query workload. One key challenge is how to utilize both structured spatial attributes and unstructured textual information during learning the index. We first divide the data objects into partitions, aiming to minimize the processing costs of the given query workload. We prove the NP-hardness of the partitioning problem and propose a machine learning model to find the optimal partitions. Then, to achieve more pruning power, we build a hierarchical structure based on the generated partitions in a bottom-up manner with a reinforcement learning-based approach. We conduct extensive experiments on real-world datasets and query workloads with various distributions, and the results show that WISK outperforms all competitors, achieving up to 8× speedup in querying time with comparable storage overhead.

Task: An Efficient Framework for Instant Error-Tolerant Spatial Keyword Queries on Road Networks

Instant spatial keyword queries return the results as soon as users type in some characters instead of a complete keyword, which allow users to query the geo-textual data in a type-as-you-search manner. However, the existing methods of instant spatial keyword queries suffer from several limitations. For example, the existing methods do not consider the typographical errors of input keywords, and cannot be applied to the road networks. To overcome these limitations, in this paper, we propose a new query type, i.e., instant error-tolerant spatial keyword queries on road networks. To answer the queries efficiently, we present a framework, termed as Task, which consists of index component, query component, and update component. In the index component, we design a novel index called reverse 2-hop label based trie, which seamlessly integrates spatial and textual information for each vertex of the road network. Based on our proposed index, we devise efficient algorithms to progressively return and update the query results in the query component and update component, respectively. Finally, we conduct extensive experiments on real-world road networks to evaluate the performance of our presented Task. Empirical results show that our proposed index and algorithms are up to 1--2 orders of magnitude faster than the baseline.

Continuous similarity join over geo-textual data streams

Continuous similarity join over geo-textual data streams

Continuous spatial keyword query processing over geo-textual data streams

Continuous spatial keyword query processing over geo-textual data streams

Efficient processing of continuous spatial-textual queries over geo-textual data stream

<p>Due to the extensive use of social media and mobile devices, unbounded and massive data is generated continuously. The need to process this big data is increasing day by day. The traditional data processing algorithms fail to cater to the need of processing data generated by various applications such as digital geo-based advertising, and recommendation systems. There has been a high demand to process continuous spatial fuzzy textual queries over data stream of spatial-textual objects with high density by present locationbased and social network-based service applications. For the spatialkeyword data stream, the performance plays a vital role as the geo information and keyword description matching is needed for every incoming streaming object. The various continuous geo-keyword query processing methods normally lack the support for fuzzy keyword matching when processing the objects from the geo-textual data stream. The edit distancebased approach with the adaptive partitioning tree index for the queries is used for fuzzy string matching and it outperforms than the existing approaches in storage cost and query performance cost.</p>

Location- and keyword-based querying of geo-textual data: a survey

With the broad adoption of mobile devices, notably smartphones, keyword-based search for content has seen increasing use by mobile users, who are often interested in content related to their geographical location. We have also witnessed a proliferation of geo-textual content that encompasses both textual and geographical information. Examples include geo-tagged microblog posts, yellow pages, and web pages related to entities with physical locations. Over the past decade, substantial research has been conducted on integrating location into keyword-based querying of geo-textual content in settings where the underlying data is assumed to be either relatively static or is assumed to stream into a system that maintains a set of continuous queries. This paper offers a survey of both the research problems studied and the solutions proposed in these two settings. As such, it aims to offer the reader a first understanding of key concepts and techniques, and it serves as an “index” for researchers who are interested in exploring the concepts and techniques underlying proposed solutions to the querying of geo-textual data.

Resource Efficient Geo-Textual Hierarchical Clustering Framework for Social IoT Applications

The Social Internet of Things (SIoT) paradigm incorporates social networking concepts with the Internet of Things (IoT) solutions to support novel services. The massive amount of data (big data) produced by SIoT necessitates efficient information processing frameworks to exploit social relationships and comprehend actionable information from real-world observations. Data from AI-enabled sensors (AIS) is typically geo-tagged, thus demanding geo-textual processing for information retrieval and analysis. Social media applications are the main source of geo-textual data as mobile users connect with millions of posts daily. The processing of big geo-textual data requires resource-efficient algorithms and frameworks. Clustering algorithms are often applied to geo-textual data to examine spatial, textual, and temporal information for event detection, sentiment analysis, and search query response. Clustering algorithms on big data are resource-hungry requiring comparisons among all data points to calculate similarity and distance metrics. Existing hybrid clustering techniques execute algorithms collectively on geo-textual data resulting in a enormous footprint for big data. We propose a resource-efficient clustering framework for AIS that hierarchically performs geo-textual clustering without significantly lowering the clustering quality. The proposed framework achieves substantial time and memory efficiency while reducing the overall resource requirements for constrained end-user and edge devices compared to the standard hybrid geo-textual clustering framework. Moreover, we augment the research work by developing open-source scripts for both hierarchical and hybrid clustering frameworks.

Efficient index-independent approaches for the collective spatial keyword queries

In abundant location-based service applications, it is necessary to process continuous spatial keyword queries over geo-textual data streaming. As an important spatial keyword query, the collective spatial keyword (CSK) query aims to find a set of objects such that it covers all the given keywords collectively, the objects within the set are nearest to the query point, and it has the minimum distance between different objects. The existing approaches for the CSK query are mostly index-based algorithms. Although these approaches gain superior performance, their applicability is significantly limited by the necessity to create an index to organize the dataset.Therefore, these index-based approaches cannot be utilized to process data streaming that prevalently exists in most location-based service applications. In addition, the existing algorithms have much room for improvement as the distances between different objects are overlooked when generating feasible candidate sets. Moreover, the results returned by the proposed algorithms could be further refined to offer better decision support for users. In this paper, a greedy algorithm and an approximate algorithm with a provable approximate bound are proposed for the CSK query. Our approaches are appropriate to the CSK queries where the datasets are not suitable to be organized by indexes and can get better query results with less objects and smaller function scores. To boost the query performance, new pruning strategies and heuristic rules are developed. The experimental results demonstrate scalability, efficiency, and effectiveness of the proposed algorithms.

Cost-Aware and Distance-Constrained Collective Spatial Keyword Query

With the proliferation of location-based services, geo-textual data is becoming ubiquitous. Objects involved in geo-textual data include geospatial locations, textual descriptions or keywords, and various attributes (e.g., a point-of-interest has its expenses and users' ratings). One prominent type of spatial keyword queries is to find, for a query consisting of a location and keywords, a set of objects that covers all the keywords and is of good quality according to some criteria. Existing studies define the criteria either based on the geospatial information of the objects solely or simply treat the geospatial and attribute information of the objects together without differentiation. As a result, they cannot provide users flexibility to express finer grained preferences on the objects. In this paper, we propose a new criterion which is to find a set of objects where the distance (defined based on the geospatial information) is at most a threshold specified by users and the cost (defined based on the attribute information) is optimized. We develop a suite of three algorithms including an exact algorithm and two approximation algorithms with provable guarantees for the problem. We conducted extensive experiments on real datasets which verified the efficiency and effectiveness of proposed algorithms.

On Nearby-Fit Spatial Keyword Queries

Geo-textual data is ubiquitous nowadays, where each object has a location and is associated with some keywords. Many types of queries based on geo-textual data, termed as spatial keyword queries , have been proposed, and are to find optimal object(s) in terms of both its (their) location(s) and keywords. In this paper, we propose a new type of query called nearby-fit spatial keyword query (NSKQ), where an optimal object is defined based not only on the location and the keywords of the object itself, but also on those of the objects nearby . For example, in an application of finding a hotel, not only the location of a hotel but also the objects near the hotel (e.g., shopping malls, restaurants, and bus stops nearby) might need to be taken into consideration. The query is proved to be NP-hard, and in order to perform the query efficiently, we developed two approximate algorithms with small constant approximation factors equal to 1.155 and 1.79. We conducted extensive experiments based on both real and synthetic datasets, which verified our algorithms.

Efficient Geo-Textual Hybrid Indexing Techniques for Moving Objects and Queries

Advancements of various Geographic Information Technologies have resulted in huge growth in Geo-Textual data. Many Indexing and searching algorithms are developed to handle this Geo-Textual data which contains spatial, textual and temporal information. In past, Indexing and searching algorithms are developed for the applications in which the object trajectory or velocity vector is known in advance and hence we can predict the future position of the objects. There are real time applications like emergency management systems, traffic monitoring, where the objects movements are unpredictable and hence future position of the objects cannot be predicted. Techniques are required to answer the geo-textual kNN query where the velocity vectors or trajectories of moving and moving queries are not known. In case of moving objects, capturing current position of the object and maintaining spatial index optimally is very much essential. The hybrid indexing techniques used earlier are based on R-tree spatial index. The nodes of the R-tree index structure are split or merged to maintain the locations of continuously moving objects, increasing the maintenance cost as compared to the grid index. In this paper a solution is proposed for creating and maintaining hybrid index for moving objects and queries based on grid and inverted list hybrid indexing techniques. The method is also proposed for finding Geo-Textual nearest neighbours for static and moving queries using hybrid index and conceptual partitioning of the grid. The overall gain reported by the experimental work using hybrid index over the non- hybrid index is 30 to 40 percent depending on the grid size chosen for mapping the data space and on the parameters of queries.

Top-k term publish/subscribe for geo-textual data streams

Massive amounts of data that contain spatial, textual, and temporal information are being generated at a rapid pace. With streams of such data, which includes check-ins and geo-tagged tweets, available, users may be interested in being kept up-to-date on which terms are popular in the streams in a particular region of space. To enable this functionality, we aim at efficiently processing two types of general top-k term subscriptions over streams of spatio-temporal documents: region-based top-k spatial-temporal term (RST) subscriptions and similarity-based top-k spatio-temporal term (SST) subscriptions. RST subscriptions continuously maintain the top-k most popular trending terms within a user-defined region. SST subscriptions free users from defining a region and maintain top-k locally popular terms based on a ranking function that combines term frequency, term recency, and term proximity. To solve the problem, we propose solutions that are capable of supporting real-life location-based publish/subscribe applications that process large numbers of SST and RST subscriptions over a realistic stream of spatio-temporal documents. The performance of our proposed solutions is studied in extensive experiments using two spatio-temporal datasets.

Pairwise Location-Aware Publish/Subscribe for Geo-Textual Data Streams

The continued proliferation of location-based social media and ridesharing services brings up the omnipresence of geo-textual data, which is often characterized by high arrival rates, diversified and duplicated content. A host of existing studies focus on efficient processing of continuous queries over geo-textual data streams by developing effective location-aware publish/subscribe systems. However, these systems often suffer from two limitations: duplicated feedings and low-quality feeding information. To address the limitations, we propose to develop a novel location-aware publish/subscribe system that feeds subscribers with geo-textual object pairs rather than individual objects. We believe that delivering object pairs to subscribers is capable of improving the information feeding quality and subscriber satisfaction. To address the problem, we propose a two-phase subscription matching scheme. The first step is online geo-textual object join. We apply a time-based sliding window that filters out out-dated geo-textual objects over the data stream. Based on the sliding window, we develop an efficient hierarchical geo-textual object online join algorithm that merges duplicated geo-textual objects. The second step is object pair matching. For each object pair, we take it as input and run a dedicated geo-textual object pair matching algorithm to find a subset of subscriptions that matches the input object pair. Our empirical study shows that our proposal is able to achieving high efficiency and effectiveness in comparison with baseline.

EFTG: Efficient and Flexible Top-K Geo-textual Publish/Subscribe

With the popularity of mobile networks and smartphones, geo-textual publish/subscribe messaging has attracted wide attention. Different from the traditional publish/subscribe format, geo-textual data is published and subscribed in the form of dynamic data flow in the mobile network. The difference creates more requirements for efficiency and flexibility. However, most of the existing Top-k geo-textual publish/subscribe schemes have the following deficiencies: (1) All publications have to be scored for each subscription, which is not efficient enough. (2) A user should take time to set a threshold for each subscription, which is not flexible enough. Therefore, we propose an efficient and flexible Top-k geo-textual publish/subscribe scheme. First, our scheme groups publish and subscribe based on text classification. Thus, only a few parts of related publications should be scored for each subscription, which significantly enhances efficiency. Second, our scheme proposes an adaptive publish/subscribe matching algorithm. The algorithm does not require the user to set a threshold. It can adaptively return Top-k results to the user for each subscription, which significantly enhances flexibility. Finally, theoretical analysis and experimental evaluation verify the efficiency and effectiveness of our scheme.

Top-K representative documents query over geo-textual data stream

The increasing popularity of location-based social networks encourages more and more users to share their experiences. It deeply impacts the decision of customers when shopping, traveling, and so on. This paper studies the problem of top-K valuable documents query over geo-textual data stream. Many researchers have studied this problem. However, they do not consider the reliability of documents, where some unreliable documents may mislead customers to make improper decisions. In addition, they lack the ability to prune documents with low representativeness. In order to increase user satisfaction in recommendation systems, we propose a novel framework named PDS. It first employs an efficiently machine learning technique named ELM to prune unreliable documents, and then uses a novel index named $\mathcal {GH}$ to maintain documents. For one thing, this index maintains a group of pruning values to filter low quality documents. For another, it utilizes the unique property of sliding window to further enhance the PDS performance. Theoretical analysis and extensive experimental results demonstrate the effectiveness of the proposed algorithms.

Top-k spatial-keyword publish/subscribe over sliding window

With the prevalence of social media and GPS-enabled devices, a massive amount of geo-textual data have been generated in a stream fashion, leading to a variety of applications such as location-base...

Towards personalized maps

Rich geo-textual data is available online and the data keeps increasing at a high speed. We propose two user behavior models to learn several types of user preferences from geo-textual data, and a prototype system on top of the user pre ference models for min ing and s e a r ch geo-textual data (called PreMiner) to support personalized maps. Different from existing recommender systems and data analysis systems, PreMiner highly personalizes user experience on maps and supports several applications, including user mobility & interests mining, opinion mining in regions, user recommendation, point-of-interest recommendation, and querying and subscribing on geo-textual data.