Project List

"A Reliable Task Assignment Strategy for Spatial Crowdsourcing in Big Data Environment With the ubiquitous deployment of the mobile devices with increasingly better communication and computation capabilities, an emerging model called spatial crowdsourcing is proposed to solve the problem of unstructured big data by publishing location-based tasks to participating workers. However, massive spatial data generated by spatial crowdsourcing entails a critical challenge that the system has to guarantee quality control of crowdsourcing. This paper first studies a practical problem of task assignment, namely reliability aware spatial crowdsourcing (RA-SC), which takes the constrained tasks and numerous dynamic workers into consideration. Specifically, the worker confidence is introduced to reflect the completion reliability of the assigned task. Our RA-SC problem is to perform task assignments such that the reliability under budget constraints is…

"An Approximate Search Framework for Big Data In the age of big data, a traditional scanning search pattern is gradually becoming unfit for a satisfying user experience due to its lengthy computing process. In this paper, we propose a sampling-based approximate search framework called Hermes, to meet user’s query demand for both accurate and efficient results. A novel metric, (ε, δ)-approximation, is presented to uniformly measure accuracy and efficiency for a big data search service, which enables Hermes to work out a feasible searching job. Based on this, we employ the bootstrapping technique to further speed up the search process. Moreover, an incremental sampling strategy is investigated to process homogeneous queries; in addition, the reuse theory of historical results is also studied for the scenario of appending data. Theoretical analyses…

"Big Data Analytics of Geosocial Media for Planning and Real-Time Decisions Geosocial Network data can be served as an asset for the authorities to make real-time decisions and future planning by analyzing geosocial media posts. However, there are millions of Geosocial Network users who are producing overwhelming of data, called “Big Data” that is challenging to be analyzed and make real-time decisions. Therefore, in this paper, we proposed an efficient system for exploring Geosocial Networks while harvesting data as well as user’s location information. A system architecture is proposed that processes an abundant amount of various social networks’ data to monitor Earth events, incidents, medical diseases, user trends, and views to make future real-time decisions and facilitate future planning. The proposed system consists of five layers, i.e., data collection, data…

"Big Data Driven Information Diffusion Analysis and Control in Online Social Networks Thanks to recent advance in massive social data and increasingly mature big data mining technologies, information diffusion and its control strategies have attracted much attention, which play pivotal roles in public opinion control, virus marketing as well as other social applications. In this paper, relying on social big data, we focus on the analysis and control of information diffusion. Specifically, we commence with analyzing the topological role of the social strengths, i.e., tie strength, partial strength, value strength, and their corresponding symmetric as well as asymmetric forms. Then, we define two critical points for the cascade information diffusion model, i.e., the information coverage critical point (CCP) and the information heat critical point (HCP). Furthermore, based on the two…

"Big Data Set Privacy Preserving through Sensitive Attribute-based Grouping There is a growing trend towards attacks on database privacy due to great value of privacy information stored in big data set. Public’s privacy are under threats as adversaries are continuously cracking their popular targets such as bank accounts. We find a fact that existing models such as K-anonymity, group records based on quasi-identifiers, which harms the data utility a lot. Motivated by this, we propose a sensitive attribute-based privacy model. Our model is the early work of grouping records based on sensitive attributes instead of quasi-identifiers which is popular in existing models. Random shuffle is used to maximize information entropy inside a group while the marginal distribution maintains the same before and after shuffling, therefore, our method maintains a better…

"Big-Data-Driven Network Partitioning for Ultra-Dense Radio Access Networks The increased density of base stations (BSs) may significantly add complexity to network management mechanisms and hamper them from efficiently managing the network. In this paper, we propose a big-data-driven network partitioning and optimization framework to reduce the complexity of the networking mechanisms. The proposed framework divides the entire radio access network (RAN) into multiple sub-RANs and each sub-RAN can be managed independently. Therefore, the complexity of the network management can be reduced. Quantifying the relationships among BSs is challenging in the network partitioning. We propose to extract three networking features from mobile traffic data to discover the relationships. Based on these features, we engineer the network partitioning solution in three steps. First, we design a hierarchical clustering analysis (HCA) algorithm to…

"Cost Aware Cloudlet Placement for Big Data Processing at the Edge As accessing computing resources from the remote cloud for big data processing inherently incurs high end-toend (E2E) delay for mobile users, cloudlets, which are deployed at the edge of networks, can potentially mitigate this problem. Although load offloading in cloudlet networks has been proposed, placing the cloudlets to minimize the deployment cost of cloudlet providers and E2E delay of user requests has not been addressed so far. The locations and number of cloudlets and their servers have a crucial impact on both the deployment cost and E2E delay of user requests. Therefore, in this paper, we propose the Cost Aware cloudlet PlAcement in moBiLe Edge computing strategy (CAPABLE) to optimize the tradeoff between the deployment cost and E2E delay.…

"CryptMDB: A Practical Encrypted MongoDB over Big Data In big data era, data are usually stored in databases for easy access and utilization, which are now woven into every aspect of our lives. However, traditional relational databases cannot address users’ demands for quick data access and calculating, since they cannot process data in a distributed way. To tackle this problem, non-relational databases such as MongoDB have emerged up and been applied in various Scenarios. Nevertheless, it should be noted that most MongoDB products fail to consider user’s data privacy. In this paper, we propose a practical encrypted MongoDB ( i.e., CryptMDB ). Specifically, we utilize an additive homomorphic asymmetric cryptosystem to encrypt user’s data and achieve strong privacy protection. Security analysis indicates that the CryptMDB can achieve confidentiality of user’s…

"Focusing on a Probability Element: Parameter Selection of Message Importance Measure in Big Data Message importance measure (MIM) is applicable to characterize the importance of information in the scenario of big data, similar to entropy in information theory. In fact, MIM with a variable parameter can make an effect on the characterization of distribution. Furthermore, by choosing an appropriate parameter of MIM, it is possible to emphasize the message importance of a certain probability element in a distribution. Therefore, parametric MIM can play a vital role in anomaly detection of big data by focusing on probability of an anomalous event. In this paper, we propose a parameter selection method of MIM focusing on a probability element and then present its major properties. In addition, we discuss the parameter selection with…

"Holistic Perspective of Big Data in Healthcare Healthcare has increased its overall value by adopting big data methods to analyze and understand its data from various sources. This article presents big data from the perspective of improving healthcare services and, also, offers a holistic view of system security and factors determining security breaches.

"Novel Common Vehicle Information Model (CVIM) for Future Automotive Vehicle Big Data Marketplaces Even though connectivity services have been introduced in many of the most recent car models, access to vehicle data is currently limited due to its proprietary nature. The European project AutoMat has therefore developed an open Marketplace providing a single point of access for brandindependent vehicle data. Thereby, vehicle sensor data can be leveraged for the design and implementation of entirely new services even beyond traffic-related applications (such as hyperlocal traffic forecasts). This paper presents the architecture for a Vehicle Big Data Marketplace as enabler of cross-sectorial and innovative vehicle data services. Therefore, the novel Common Vehicle Information Model (CVIM) is defined as an open and harmonized data model, allowing the aggregation of brandindependent and generic data…

"Online Data Deduplication for In-Memory Big-Data Analytic Systems Given a set of files that show a certain degree of similarity, we consider a novel problem of performing data redundancy elimination across a set of distributed worker nodes in a shared-nothing in-memory big data analytic system. The redundancy elimination scheme is designed in a manner that is: (i) space-efficient: the total space needed to store the files is minimized and, (ii) access-isolation: data shuffling among server is also minimized. In this paper, we first show that finding an access-efficient and space optimal solution is an NP-Hard problem. Following this, we present the file partitioning algorithms that locate access-efficient solutions in an incremental manner with minimal algorithm time complexity (polynomial time). Our experimental verification on multiple data sets confirms that the proposed…

"Traffic-aware Task Placement with Guaranteed Job Completion Time for Geo-distributed Big Data Big data analysis is usually casted into parallel jobs running on geo-distributed data centers. Different from a single data center, geo-distributed environment imposes big challenges for big data analytics due to the limited network bandwidth between data centers located in different regions.Although research efforts have been devoted to geo-distributed big data, the results are still far from being efficient because of their suboptimal performance or high complexity. In this paper, we propose a traffic-aware task placement to minimize job completion time of big data jobs. We formulate the problem as a non-convex optimization problem and design an algorithm to solve it with proved performance gap. Finally, extensive simulations are conducted to evaluate the performance of our proposal. The…

"QoS-Aware Data Replications and Placements for Query Evaluation of Big Data Analytics Enterprise users at different geographic locations generate large-volume data and store their data at different geographic datacenters. These users may also issue ad hoc queries of big data analytics on the stored data to identify valuable information in order to help them make strategic decisions. However, it is well known that querying such large-volume big data usually is time-consuming and costly. Sometimes, users are only interested in timely approximate rather than exact query results. When this approximation is the case, applications must sacrifice either timeliness or accuracy by allowing either the latency of delivering more accurate results or the accuracy error of delivered results based on the samples of the data, rather than the entire set of data…

"Twitter data analysis and visualizations using the R language on top of the Hadoop platform The main objective of the work presented within this paper was to design and implement the system for twitter data analysis and visualization in R environment using the big data processing technologies. Our focus was to leverage existing big data processing frameworks with its storage and computational capabilities to support the analytical functions implemented in R language. We decided to build the backend on top of the Apache Hadoop framework including the Hadoop HDFS as a distributed filesystem and MapReduce as a distributed computation paradigm. RHadoop packages were then used to connect the R environment to the processing layer and to design and implement the analytical functions in a distributed manner. Visualizations were implemented on…

A Micro-video Recommendation System Based on Big Data With the development of the Internet and social networking service, the micro-video is becoming more popular, especially for youngers. However, for many users, they spend a lot of time to get their favorite micro-videos from amounts videos on the Internet; for the micro-video producers, they do not know what kinds of viewers like their products. Therefore, this paper proposes a micro-video recommendation system. The recommendation algorithms are the core of this system. Traditional recommendation algorithms include content-based recommendation, collaboration recommendation algorithms, and so on. At the Bid Data times, the challenges what we meet are data scale, performance of computing, and other aspects. Thus, this paper improves the traditional recommendation algorithms, using the popular parallel computing framework to process the Big Data.…