Severe environmental events have extreme effects on all segments of society, including criminal activity. Extreme weather events, such as tropical storms, fires, and floods create instability in communities, and can be exploited by criminal organizations. Here we investigate the potential impact of catastrophic storms on the criminal activity of human trafficking. We propose three theories of how these catastrophic storms might impact trafficking and provide evidence for each. Researching human trafficking is made difficult by its illicit nature and the obscurity of high-quality data. Here, we analyze online advertisements for services which can be collected at scale and provide insights into traffickers' behavior. To successfully combine relevant heterogenous sources of information, as well as spatial and temporal structure, we propose a collective, probabilistic approach. We implement this approach with Probabilistic Soft Logic, a probabilistic programming framework which can flexibly model relational structure and for which inference of future locations is highly efficient. Furthermore, this framework can be used to model hidden structure, such as latent links between locations. Our proposed approach can model and predict how traffickers move. In addition, we propose a model which learns connections between locations. This model is then adapted to have knowledge of environmental events, and we demonstrate that incorporating knowledge of environmental events can improve prediction of future locations. While we have validated our models on the impact of severe weather on human trafficking, we believe our models can be generalized to a variety of other settings in which environmental events impact human behavior.

Recently, much attention has been given to extracting tables from Web data. In this problem, the column definitions and tuples (such as what "company" is headquartered in what "city,") are extracted from Web text, structured Web data such as lists, or results of querying the deep Web, creating the table of interest. In this paper, we examine the problem of extracting and discovering multiple tables in a given domain, generating a truly multi-relational database as output. Beyond discovering the relations that define single tables, our approach discovers and leverages "within column" set membership relations, and discovers relations across the extracted tables (e.g., joins). By leveraging within-column relations our method can extract table instances that are ambiguous or rare, and by discovering joins, our method generates truly multi-relational output. Further, our approach uses taxonomic queries to bootstrap the extraction, rather than the more traditional "seed instances." Creating seeds often requires more domain knowledge than taxonomic queries, and previous work has shown that extraction methods may be sensitive to which input seeds they are given. We test our approach on two real world domains: NBA basketball and cancer information. Our results demonstrate that our approach generates databases of relevant tables from disparate Web information, and discovers the relations between them. Further, we show that by leveraging the "within column" relation our approach can identify a significant number of relevant tuples that would be difficult to do so otherwise.

Active learners alleviate the burden of labeling large amounts of data by detecting and asking the user to label only the most informative examples in the domain. We focus here on active learning for multi-view domains, in which there are several disjoint subsets of features (views), each of which is sufficient to learn the target concept. In this paper we make several contributions. First, we introduce Co-Testing, which is the first approach to multi-view active learning. Second, we extend the multi-view learning framework by also exploiting weak views, which are adequate only for learning a concept that is more general/specific than the target concept. Finally, we empirically show that Co-Testing outperforms existing active learners on a variety of real world domains such as wrapper induction, Web page classification, advertisement removal, and discourse tree parsing.

Record linkage is the process of determining that two records refer to the same entity. A key subprocess is evaluating how well the individual fields, or attributes, of the records match each other. One approach to matching fields is to use hand-written domain-specific rules. This "expert systems" approach may result in good performance for specific applications, but it is not scalable. This paper describes a new machine learning approach that creates expert-like rules for field matching. In our approach, the relationship between two field values is described by a set of heterogeneous transformations. Previous machine learning methods used simple models to evaluate the distance between two fields. However, our approach enables more sophisticated relationships to be modeled, which better capture the complex domain specific, common-sense phenomena that humans use to judge similarity. We compare our approach to methods that rely on simpler homogeneous models in several domains. By modeling more complex relationships we produce more accurate results.

Our goal is to automatically extract data from semi-structured webn sites. Previously, researchers have developed two types of supervised learning approaches for extracting web data: methods that create precise, site-specific extraction rules and methods that learn less-precise site-independent extraction rules. In either case, significant training is required. In this paper, we describe a third, more ambitious approach, where we use unsupervised learning to analyze sites and discover their structure. Our method relies on a set of heterogeneous "experts", each of which is capable of identifying certain types of generic structure. Each expert represents its discoveries as "hints". Based on these hints, our system clusters the pages and identifies semi-structured data that can be extracted. To identify a good clustering, we use a probabilistic model of the hint-generation process. The paper describes our formulation of the fully-automatic web-extraction problem, our clustering approach, and our results on a set of experiments.

Many Web sites, especially those that dynamically generate HTML pages to display the results of a user's query, present information in the form of list or tables. Current tools that allow applications to programmatically extract this information rely heavily on user input, often in the form of labeled extracted records. The sheer size and rate of growth of the Web make any solution that relies primarily on user input is infeasible in the long term. Fortunately, many Web sites contain much explicit and implicit structure, both in layout and content, that we can exploit for the purpose of information extraction. This paper describes an approach to automatic extraction and segmentation of records from Web tables. Automatic methods do not require any user input, but rely solely on the layout and content of the Web source. Our approach relies on the common structure of many Web sites, which present information as a list or a table, with a link in each entry leading to a detail page containing additional information about that item. We describe two algorithms that use redundancies in the content of table and detail pages to aid in information extraction. The first algorithm encodes additional information provided by detail pages as constraints and finds the segmentation by solving a constraint satisfaction problem. The second algorithm uses probabilistic inference to find the record segmentation. We show how each approach can exploit the web site structure in a general, domain-independent manner, and we demonstrate the effectiveness of each algorithm on a set of twelve Web sites.

The proliferation of online information sources has led to an increased use of wrappers for extracting data from Web sources. While most of the previous research has focused on quick and efficient generation of wrappers, the development of tools for wrapper maintenance has received less attention. This is an important research problem because Web sources often change in ways that prevent the wrappers from extracting data correctly. We present an efficient algorithm that learns structural information about data from positive examples alone. We describe how this information can be used for two wrapper maintenance applications: wrapper verification and reinduction. The wrapper verification system detects when a wrapper is not extracting correct data, usually because the Web source has changed its format. The reinduction algorithm automatically recovers from changes in the Web source by identifying data on Web pages so that a new wrapper may be generated for this source. To validate our approach, we monitored 27 wrappers over a period of a year. The verification algorithm correctly discovered 35 of the 37 wrapper changes, and made 16 mistakes, resulting in precision of 0.73 and recall of 0.95. We validated the reinduction algorithm on ten Web sources. We were able to successfully reinduce the wrappers, obtaining precision and recall values of 0.90 and 0.80 on the data extraction task.

The task of object identification occurs when integrating information from multiple websites. The same data objects can exist in inconsistent text formats across sites, making it difficult to identify matching objects using exact text match. Previous methods of object identification have required manual construction of domain-specific string transformations or manual setting of general transformation parameter weights for recognizing format inconsistencies. This manual process can be time consuming and error-prone. We have developed an object identification system called Active Atlas [18], which applies a set of domain-independent string transformations to compare the objects' shared attributes in order to identify matching objects. In this paper, we discuss extensions to the Active Atlas system, which allow it to learn to tailor the weights of a set of general transformations to a specific application domain through limited user input. The experimental results demonstrate that this approach achieves higher accuracy and requires less user involvement than previous methods across various application domains.

Amixed-initiative plannerin our context is one in which either the human or the computer can spontaneously provide the content of the same input fields. A multi-source planneris one that accesses multiple external information sources in parallel, using separate threads. This type of highly dynamic user interface is desirable but presents a challenge in "keeping the user in control" because it can be confusing to understand which fields of the form currently "belong" to the user, which ones "belong" to the system, how these two interact, and when and how their ownership changes.

While the information resources on the Web are vast, the sources are often hard to nd, painful to use, and dicult to integrate. Wehavedeveloped the Heracles framework for building Web-based information assistants. This framework provides the infrastructure to rapidly construct new applications that extract information from multiple Web sources and interactively integrate the data using a dynamic, hierarchical constraint network. This paper describes the core technologies that comprise the framework, including information extraction, hierarchical template representation, and constraint propagation. In addition, we present an application of this framework, the ###### #########, which is an interactivetravel planning system. We also briey describe our experience using the same framework to build a second application, the ######### #########, which extracts and integrates geographic-related data about countries thorughout the world. We believe these types of information assistants provide a signicant step forward in fully exploiting the information available on the Internet. 1.

The Web is based on a browsing paradigm that makes it difficult to retrieve and integrate data from multiple sites. Today, the only way to do this is to build specialized applications, which are time-consuming to develop and difficult to maintain. We have addressed this problem by creating the technology and tools for rapidly constructing information agents that extract, query, and integrate data from web sources. Our approach is based on a uniform representation that makes it simple and efficient to integrate multiple sources. Instead of building specialized algorithms for handling web sources, we have developed methods for mapping web sources into this uniform representation. This approach builds on work from knowledge representation, databases, machine learning and automated planning. The resulting system, called Ariadne, makes it fast and easy to build new information agents that access existing web sources. Ariadne also makes it easy to maintain these agents and incorporate new sources as they become available.

Although much has been written about various information integration technologies, little has been said regarding how to combine these technologies together to build an entire application. We demonstrate TheaterLoc, an information integration application that allows users to retrieve information about theatres and restaurants for various U.S. cities, including an interactive map depicting their relative locations. The data retrieved by TheaterLoc comes from five distinct heterogeneous and distributed sources. The enabling technology used to achieve the integration includes: the Ariadne information mediator, a Web site wrapper learning tool, the Theseus execution system, and a mechanism for distributed spatial query planning. Our system is novel because it demonstrates how "virtual applications" can be rapidly built from a set of integration tools and existing online data sources.

The Web is based on a browsing paradigm that makes it difficult to retrieve and integrate data from multiple sites. Today, the only way to achieve this integration is by building specialized applications, which are time-consuming to develop and difficult to maintain. We are addressing this problem by creating the technology and tools for rapidly constructing information mediators that extract, query, and integrate data from web sources. The resulting system, called Ariadne, makes it feasible to rapidly build information mediators that access existing web sources.

For many years, the intuitions underlying partial-order planning were largely taken for granted. Only in the past few years has there been renewed interest in the fundamental principles underlying this paradigm. In this paper, we present a rigorous comparative analysis of partial-order and total-order planning by focusing on two specific planners that can be directly compared. We show that there are some subtle assumptions that underly the wide-spread intuitions regarding the supposed efficiency of partial-order planning. For instance, the superiority ofpartial-order planning can depend critically upon the search strategy and the structure of the search space. Understanding the underlying assumptions is crucial for constructing efficient planners.