Probability Distributions.- Linear Models for Regression.- Linear Models for Classification.- Neural Networks.- Kernel Methods.- Sparse Kernel Machines.- Graphical Models.- Mixture Models and EM.- Approximate Inference.- Sampling Methods.- Continuous Latent Variables.- Sequential Data.- Combining Models.

Pattern Recognition and Machine Learning

Data Mining - Concepts and Techniques.

Models for the processes by which ideas and influence propagate through a social network have been studied in a number of domains, including the diffusion of medical and technological innovations, the sudden and widespread adoption of various strategies in game-theoretic settings, and the effects of "word of mouth" in the promotion of new products. Recently, motivated by the design of viral marketing strategies, Domingos and Richardson posed a fundamental algorithmic problem for such social network processes: if we can try to convince a subset of individuals to adopt a new product or innovation, and the goal is to trigger a large cascade of further adoptions, which set of individuals should we target?We consider this problem in several of the most widely studied models in social network analysis. The optimization problem of selecting the most influential nodes is NP-hard here, and we provide the first provable approximation guarantees for efficient algorithms. Using an analysis framework based on submodular functions, we show that a natural greedy strategy obtains a solution that is provably within 63% of optimal for several classes of models; our framework suggests a general approach for reasoning about the performance guarantees of algorithms for these types of influence problems in social networks.We also provide computational experiments on large collaboration networks, showing that in addition to their provable guarantees, our approximation algorithms significantly out-perform node-selection heuristics based on the well-studied notions of degree centrality and distance centrality from the field of social networks.

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Maximizing the Spread of Influence through a Social Network

The book Knowledge Discovery in Databases, edited by Piatetsky-Shapiro and Frawley [PSF91], is an early collection of research papers on knowledge discovery from data. The book Advances in Knowledge Discovery and Data Mining, edited by Fayyad, Piatetsky-Shapiro, Smyth, and Uthurusamy [FPSSe96], is a collection of later research results on knowledge discovery and data mining. There have been many data mining books published in recent years, including Predictive Data Mining by Weiss and Indurkhya [WI98], Data Mining Solutions: Methods and Tools for Solving Real-World Problems by Westphal and Blaxton [WB98], Mastering Data Mining: The Art and Science of Customer Relationship Management by Berry and Linofi [BL99], Building Data Mining Applications for CRM by Berson, Smith, and Thearling [BST99], Data Mining: Practical Machine Learning Tools and Techniques by Witten and Frank [WF05], Principles of Data Mining (Adaptive Computation and Machine Learning) by Hand, Mannila, and Smyth [HMS01], The Elements of Statistical Learning by Hastie, Tibshirani, and Friedman [HTF01], Data Mining: Introductory and Advanced Topics by Dunham, and Data Mining: Multimedia, Soft Computing, and Bioinformatics by Mitra and Acharya [MA03]. There are also books containing collections of papers on particular aspects of knowledge discovery, such as Machine Learning and Data Mining: Methods and Applications edited by Michalski, Brakto, and Kubat [MBK98], and Relational Data Mining edited by Dzeroski and Lavrac [De01], as well as many tutorial notes on data mining in major database, data mining and machine learning conferences.

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Data Mining: Concepts and Techniques (2nd edition)

While the study of psychology has offered little in the way of explaining the creative process, Koestler examines the idea that we are at our most creative when rational thought is suspended--for example, in dreams and trancelike states. All who read The Act of Creation will find it a compelling and illuminating book.

The Act of Creation

With the prominence of location-based services and social networks in recent years, huge amounts of spatio-temporal document collections (e.g., geo-tagged tweets) have been generated. These data collections often imply user’s ideas on different products and thus are helpful for business owners to explore hot topics of their brands and the competition relation to other brands in different spatial regions during different periods. In this work, we aim to mine the topics and the market competition of different brands over each topic for a category of business (e.g., coffeehouses) from spatio-temporal documents within a user-specified region and time period. To support such spatio-temporal search online in an exploratory manner, we propose a novel framework equipped by (1) a generative model for mining topics and market competition, (2) an Octree-based off-line pre-training method for the model and (3) an efficient algorithm for combining pre-trained models to return the topics and market competition on each topic within a user-specified pair of region and time span. Extensive experiments show that our framework is able to improve the runtime by up to an order of magnitude compared with baselines while achieving similar model quality in terms of training log-likelihood.

Exploring market competition over topics in spatio-temporal document collections

With the proliferation of mobile devices and location-based services, continuous generation of massive volume of streaming spatial objects (i.e., geo-tagged data) opens up new opportunities to address real-world problems by analyzing them. In this paper, we present a novel continuous bursty region detection ( surge ) problem that aims to continuously detect a bursty region of a given size in a specified geographical area from a stream of spatial objects. Specifically, a bursty region shows maximum spike in the number of spatial objects in a given time window. The surge problem is useful in addressing several real-world challenges such as surge pricing problem in online transportation and disease outbreak detection. To solve the problem, we propose an exact solution and two approximate solutions, and the approximation ratio is $\frac{1-\alpha }{4}$ 1 - α 4 in terms of the burst score, where $\alpha$ α is a parameter to control the burst score. We further extend these solutions to support detection of t op- $k$ k bursty regions . Extensive experiments with real-world data are conducted to demonstrate the efficiency and effectiveness of our solutions.

SURGE: Continuous Detection of Bursty Regions Over a Stream of Spatial Objects

We study a new kind of query – a Reverse k Nearest Neighbor Search over Trajectories (RkNNT), which can be used for route planning and capacity estimation in the transportation field. Given a set of existing routes DR, a set of passenger transitions DT, and a query route Q, an RkNNT query returns all transitions that take Q as one of its k nearest travel routes. We develop an index to handle dynamic trajectory updates, so that the most up-to-date transition data is available for answering an RkNNT query using a filter-refine processing framework. Further, an application of using RkNNT to plan the optimal route in bus networks, namely MaxRkNNT, is proposed and studied. Experiments on real datasets demonstrate the efficiency and scalability of our approaches. In the future, the RkNNT can be extended to applied to the traffic prediction.

Reverse k Nearest Neighbor Search over Trajectories (Extended Abstract)

High-dimensional sparse data is prevalent in many real-life applications. In this paper, we propose a novel index structure for accelerating similarity search in high-dimensional sparse databases, named ISIS, which stands for Indexing Sparse databases using Inverted fileS. ISIS clusters a dataset and converts the original high-dimensional space into a new space where each dimension represents a cluster; furthermore, the key values in the new space are used by Inverted-files indexes. We also propose an extension of ISIS, named ISIS+, which partitions the data space into lower dimensional subspaces and clusters the data within each subspace. Extensive experimental study demonstrates the superiority of our approaches in high-dimensional sparse databases.

ISIS: a new approach for efficient similarity search in sparse databases

Spatial-textual content is becoming increasingly prevalent:

— Location-based services from major commercial search engines. For example, in Google Maps many (geo-referenced) points of interest--e.g., clinics, stores, tourist attractions, hotels, entertainment services, public transport, and public services--are being associated with descriptive texts.

— Websites with location content. For example, online yellow pages, documents of Wikipedia, Tweets in Twitter, photos in Flickr, points of interest in Foursquare, etc.

— Moving objects associated with texts. An example scenario is that each healthcare worker has certain skills, described in keywords, and moves around in a large hospital.

These call for spatial-keyword search from the perspectives of both the users and the service providers. From the user's perspective, users may want to issue queries such as "health screening clinics near NTU, Singapore", which has a location component "NTU, Singapore" and a keyword component "health screening clinics". Indeed, location-based services (e.g., Google Maps) and Twitter already support such types of queries. From the perspective of service providers, they want to know the number of customers who are interested in their services compared with competitors. For example, a nutrition store may want to find potential customers whose profiles are relevant to the products of the store and whose locations are close to this store. The talk covers recent results [1---6] on spatial keyword querying obtained by the speaker and his colleagues.

Gao Cong

Papers

Exploring market competition over topics in spatio-temporal document collections

SURGE: Continuous Detection of Bursty Regions Over a Stream of Spatial Objects

Reverse k Nearest Neighbor Search over Trajectories (Extended Abstract)

ISIS: a new approach for efficient similarity search in sparse databases

Spatial keyword queries