Open educational resources (OERs) can provide useful online materials to facilitate teaching and learning. It is desirable to provide a focused list for the global computing education community. In this short paper, we present the top 10 computer science OERs based on voting, as organized by the MERLOT Computer Science Editorial Board. These OERs cover various important computing topics, including general computing topics, programming, algorithms, machine learning etc. They provide good references for instructors to complement their lectures and strengthen student computing backgrounds.

With the development of social network platforms, discussion forums, and question answering websites, a huge number of short messages that typically contain a few words for an individual document are posted by online users. In these short messages, emotions are frequently embedded for communicating opinions, expressing friendship, and promoting influence. It is quite valuable to detect emotions from short messages, but the corresponding task suffers from the sparsity of feature space. In this article, we first generate term groups co-occurring in the same context to enrich the number of features. Then, two basic supervised topic models are proposed to associate emotions with topics accurately. To reduce the time cost of parameter estimation, we further propose an accelerated algorithm for our basic models. Extensive evaluations using three short corpora validate the efficiency and effectiveness of the accelerated models for predicting the emotions of unlabeled documents, in addition to generate the topic-level emotion lexicons.

Cross-domain sentiment classification aims to tag sentiments for a target domain by labeled data from a source domain. Due to the difference between domains, the accuracy of a trained classifier may be very low. In this paper, we propose a boosting-based learning framework named TR-TrAdaBoost for cross-domain sentiment classification. We firstly explore the topic distribution of documents, and then combine it with the unigram TrAdaBoost. The topic distribution captures the domain information of documents, which is valuable for cross-domain sentiment classification. Experimental results indicate that TR-TrAdaBoost represents documents well and boost the performance and robustness of TrAdaBoost.

We have developed a method called skill2vec, which applies big data techniques to automatically analyze the learning data to discover skill relationship, leading to a more objective and data-informed decision making. Skill2vec is a neural network architecture which can transform a skill to a new vector space called embedding. The embedding can facilitate the comparison and visualization of different skills and their relationship. We conducted a pilot experiment using benchmark dataset to demonstrate the effectiveness of our method.

The rapid growth of population has posed a challenge to people for discovering new followees in uni-directional social networks. Intuitively, a user's adoption of others as followees may motivated by her interest as well as social connection. Therefore, it is worth-while to consider both factors at the same time for better recommendations. Previous recommender works on implicit follow or not feedbacks become unqualified, mainly because of the coarse users' preferences inferring, which cannot distinguish whether one follows the other is based on her social connection or individual interest. In this paper, we present a new user recommendation method which is capable of recommending candidate followees who have similar interest and closer social connection relevant to a target user. As its core, a novel topic model namely UIS-LDA is designed to jointly model a user's preferences with respect to the set of latent interest topics and social topics. The experiments using Twitter dataset proves that our proposed method effective in improving the Precision, Conversion Rate F1 score and NDCG.

Automated analysis and assessment of students' programs, typically implemented in automated program assessment systems (APASs), are very helpful to both students and instructors in modern day computer programming classes. The mainstream of APASs employs a black-box testing approach which compares students' program outputs with instructor-prepared outputs. A common weakness of existing APASs is their inflexibility and limited capability to deal with admissible output variants, that is, outputs produced by acceptable correct programs that differ from the instructor's. This paper proposes a more robust framework for automatically modelling and analysing student program output variations based on a novel hierarchical program output structure called HiPOS. Our framework assesses student programs by means of a set of matching rules tagged to the HiPOS, which produces a better verdict of correctness. We also demonstrate the capability of our framework by means of a pilot case study using real student programs.

We develop an unsupervised learning framework for extracting popular product attributes from product description pages originated from different E-commerce Web sites. Unlike existing information extraction methods that do not consider the popularity of product attributes, our proposed framework is able to not only detect popular product features from a collection of customer reviews but also map these popular features to the related product attributes. One novelty of our framework is that it can bridge the vocabulary gap between the text in product description pages and the text in customer reviews. Technically, we develop a discriminative graphical model based on hidden Conditional Random Fields. As an unsupervised model, our framework can be easily applied to a variety of new domains and Web sites without the need of labeling training samples. Extensive experiments have been conducted to demonstrate the effectiveness and robustness of our framework.

With the rapid growth of massive online open courses (MOOCs) on the Web, it is essential to provide learners with appropriate assistance in courses and learning materials. The extant approaches of personalized course search mainly consider historical learnt and enrolled courses of learners. That is, those courses which are contently similar to previous courses in learner profiles will be highlighted in the ranking results of the personalized course search. However, these approaches mainly neglect two distinguished characteristics in this domain, which are (i) context-dependent: course search which is highly correlated with learner contexts, e.g., a learner may have the individual learning schedule of the courses to be retrieved depending on the temporal contexts; and (ii) knowledge-constrained: learners are more willing to search and enroll in the courses that they have sufficient pre-knowledge about. To incorporate these two domain characteristics of the personalized course search, we therefore present a novel approach based on hybrid learner profile in this paper. Furthermore, we conduct the experiments which compare the performance of different methods on a dataset to verify the effectiveness of the proposed method for the personalized course search.

An important way to improve users’ satisfaction in Web search is to assist them by issuing more effective queries. One such approach is query reformulation, which generates new queries according to the current query issued by users. A common procedure for conducting reformulation is to generate some candidate queries first, then a scoring method is employed to assess these candidates. Currently, most of the existing methods are context based. They rely heavily on the context relation of terms in the history queries and cannot detect and maintain the semantic consistency of queries. In this article, we propose a graphical model to score queries. The proposed model exploits a latent topic space, which is automatically derived from the query log, to detect semantic dependency of terms in a query and dependency among topics. Meanwhile, the graphical model also captures the term context in the history query by skip-bigram and n-gram language models. In addition, our model can be easily extended to consider users’ history search interests when we conduct query reformulation for different users. In the task of candidate query generation, we investigate a social tagging data resource—Delicious bookmark—to generate addition and substitution patterns that are employed as supplements to the patterns generated from query log data.

We have developed a novel intelligent recommendation system for improving rating prediction by collaborative filtering incorporated with preference regularization. One characteristic of the preference regularizer is that it can effectively capture the rating information and ranking information of items, resulting in a decision that is coherent to both rating and ranking of items. Another characteristic of our designed preference regularizer is that it models the difference in the rating to an item between a pair of users in a probabilistic manner. This essentially imposes soft constraint that similar users should have similar rating to an item. We have conducted extensive experiments on real-world datasets to evaluate our framework. We have also compared our framework with other existing works to illustrate the effectiveness of our framework. Experimental results show that our framework achieves a promising prediction performance and outperforms the existing works.

We develop a new framework to achieve the goal of Wikipedia entity expansion and attribute extraction from the Web. Our framework takes a few existing entities that are automatically collected from a particular Wikipedia category as seed input and explores their attribute infoboxes to obtain clues for the discovery of more entities for this category and the attribute content of the newly discovered entities. One characteristic of our framework is to conduct discovery and extraction from desirable semi-structured data record sets which are automatically collected from the Web. A semi-supervised learning model with Conditional Random Fields is developed to deal with the issues of extraction learning and limited number of labeled examples derived from the seed entities. We make use of a proximate record graph to guide the semi-supervised learning process. The graph captures alignment similarity among data records. Then the semi-supervised learning process can leverage the unlabeled data in the record set by controlling the label regularization under the guidance of the proximate record graph. Extensive experiments on different domains have been conducted to demonstrate its superiority for discovering new entities and extracting attribute content.

We propose a framework for adapting text mining models that discovers low-rank shared concept space. Our major characteristic of this concept space is that it explicitly minimizes the distribution gap between the source domain with sufficient labeled data and the target domain with only unlabeled data, while at the same time it minimizes the empirical loss on the labeled data in the source domain. Our method is capable of conducting the domain adaptation task both in the original feature space as well as in the transformed Reproducing Kernel Hilbert Space (RKHS) using kernel tricks. Theoretical analysis guarantees that the error of our adaptation model can be bounded with respect to the embedded distribution gap and the empirical loss in the source domain. We have conducted extensive experiments on two common text mining problems, namely, document classification and information extraction, to demonstrate the efficacy of our proposed framework.

Web data record extraction aims at extracting a set of similar object records from a single webpage. These records have similar attributes or fields and are presented with a regular format in a coherent region of the page. To tackle this problem, most existing works analyze the DOM tree of an input page. One major limitation of these methods is that the lack of a global view in detecting data records from an input page results in a myopic decision. Their brute-force searching manner in detecting various types of records degrades the flexibility and robustness. We propose a Structure-Knowledge-Oriented Global Analysis (Skoga) framework which can perform robust detection of different-kinds of data records and record regions. The major component of the Skoga framework is a DOM structure-knowledge-driven detection model which can conduct a global analysis on the DOM structure to achieve effective detection. The DOM structure knowledge consists of background knowledge as well as statistical knowledge capturing different characteristics of data records and record regions, as exhibited in the DOM structure. The background knowledge encodes the semantics of labels indicating general constituents of data records and regions. The statistical knowledge is represented by some carefully designed features that capture different characteristics of a single node or a node group in the DOM. The feature weights are determined using a development dataset via a parameter estimation algorithm based on a structured output support vector machine. An optimization method based on the divide-and-conquer principle is developed making use of the DOM structure knowledge to quantitatively infer and recognize appropriate records and regions for a page. Extensive experiments have been conducted on four datasets. The experimental results demonstrate that our framework achieves higher accuracy compared with state-of-the-art methods.

With respect to the increasing trend that students acquire information from the Internet for their formal or informal learning, we aim at analyzing the use of social bookmarking to help students collaboratively access useful and creditable Web resources, facilitating collaborative learning. We also investigate the use of social bookmarking for after-school learning. Social bookmarking allows users to search for, tag, and share Web resources, and hence recommend students Web resources that are potentially useful and relevant. Experiments were conducted to study how social bookmarking can improve the quality of the acquired Web resource. In particular, students using social bookmarking could acquire a more focused and high quality set of Web resources compared with students not using social bookmarking.

An important way to improve users' satisfaction in Web search is to assist them to issue more effective queries. One such approach is query refinement (reformulation), which generates new queries according to the current query issued by users. A common procedure for conducting refinement is to generate some candidate queries first, and then a scoring method is designed to assess the quality of these candidates. Currently, most of the existing methods are context based. They rely heavily on the context relation of terms in the historical queries, and cannot detect and maintain the semantic consistency of queries. In this paper, we propose a graphical model to score queries. The proposed model exploits a latent topic space, which is automatically derived from the query log, to assess the semantic dependency of terms in a query. In the graphical model, both term context dependency and topic context dependency are considered. This also makes it feasible to score some queries which do not have much available historical term context information. We also utilize social tagging data in the candidate query generation process. Based on the observation that different users may tag the same resource with different tags of similar meaning, we propose a method to mine these term pairs for new candidate query construction.

We start with the premise that incorporating knowledge into web software can make the web wiser due to the knowledge-is-power hypothesis. This paper explores to incorporate knowledge with web engineering, in the process proposing a multiplicity-based methodology to create wise web systems more effectively. The paper examines the nature of knowledge, linking to artificial intelligence hypotheses and the associated shift in views. From a multidimensional knowledge structure, it argues for a dual modelling view to organizing the multi-faceted knowledge at knowledge level. Subsequently, the model-based software development method that uses the dual structural and behavioural models is mixed with the web system development, taking the belief that web engineering shares a lot of similarities with conventional software engineering. The later part of the paper concentrates on resolving the two difficult tasks of switching between system views and deepening abstraction levels.

We have developed a framework aiming at normalizing product attributes from Web pages collected from different Web sites without the need of labeled training examples. It can deal with pages composed of different layout format and content in an unsupervised manner. As a result, it can handle a variety of different domains with minimal effort. Our model is based on a generative probabilistic graphical model incorporated with Hidden Markov Models (HMM) considering both attribute names and attribute values to extract and normalize text fragments from Web pages in a unified manner. Dirichlet Process is employed to handle the unlimited number of attributes in a domain. An unsupervised inference method is proposed to predict the unobservable variables. We have also developed a method to automatically construct a domain ontology using the normalized product attributes which are the output of the inference on the graphical model. We have conducted extensive experiments and compared with existing works using prouct Web pages collected from real-world Web sites in three different domains to demonstrate the effectiveness of our framework.

Dataset shift from the training data in a source domain to the data in a target domain poses a great challenge for many statistical learning methods. Most algorithms can be viewed as exploiting only the first-order statistics, namely, the empirical mean discrepancy to evaluate the distribution gap. Intuitively, considering only the empirical mean may not be statistically efficient. In this paper, we propose a non-parametric distance metric with a good property which jointly considers the empirical mean (Location) and sample covariance (Scatter) difference. More specifically, we propose an improved symmetric Stein's loss function which combines the mean and covariance discrepancy into a unified Bregman matrix divergence of which Jensen-Shannon divergence between normal distributions is a particular case. Our target is to find a good feature representation which can reduce the distribution gap between different domains, at the same time, ensure that the new derived representation can encode most discriminative components with respect to the label information. We have conducted extensive experiments on several document classification datasets to demonstrate the effectiveness of our proposed method.

This paper presents a Bayesian learning framework for adapting information extraction wrappers with new attribute discovery, reducing human effort in extracting precise information from unseen Web sites. Our approach aims at automatically adapting the information extraction knowledge previously learned from a source Web site to a new unseen site, at the same time, discovering previously unseen attributes. Two kinds of text-related clues from the source Web site are considered. The first kind of clue is obtained from the extraction pattern contained in the previously learned wrapper. The second kind of clue is derived from the previously extracted or collected items. A generative model for the generation of the site-independent content information and the site-dependent layout format of the text fragments related to attribute values contained in a Web page is designed to harness the uncertainty involved. Bayesian learning and expectation-maximization (EM) techniques are developed under the proposed generative model for identifying new training data for learning the new wrapper for new unseen sites. Previously unseen attributes together with their semantic labels can also be discovered via another EM-based Bayesian learning based on the generative model. We have conducted extensive experiments from more than 30 real-world Web sites in three different domains to demonstrate the effectiveness of our framework.

One common predictive modeling challenge occurs in text mining problems is that the training data and the operational (testing) data are drawn from different underlying distributions. This poses a great difficulty for many statistical learning methods. However, when the distribution in the source domain and the target domain are not identical but related, there may exist a shared concept space to preserve the relation. Consequently a good feature representation can encode this concept space and minimize the distribution gap. To formalize this intuition, we propose a domain adaptation method that parameterizes this concept space by linear transformation under which we explicitly minimize the distribution difference between the source domain with sufficient labeled data and target domains with only unlabeled data, while at the same time minimizing the empirical loss on the labeled data in the source domain. Another characteristic of our method is its capability for considering multiple classes and their interactions simultaneously. We have conducted extensive experiments on two common text mining problems, namely, information extraction and document classification to demonstrate the effectiveness of our proposed method. Copyright 2009 ACM.

We propose a semi-supervised framework incorporating feature mapping with multiclass classification. By learning multiple classification tasks simultaneously, this framework can learn the latent feature space effectively for both labeled and unlabeled data. The knowledge in the transformed space can be transferred not only between the labeled and unlabeled data, but also across multiple classes, so as to improve the classification performance given a small amount of labeled data. We show that this problem is equivalent to a sequential convex optimization problem by applying constraint concave-convex procedure (CCCP). Efficient algorithm with theoretical guarantee is proposed and computational issue is investigated. Extensive experiments have been conducted to demonstrate the effectiveness of our proposed framework.

We have developed an approach for analyzing online job advertisements in different domains (industries) from different regions worldwide. Our approach is able to extract precise information from the text content supporting useful employment market analysis locally and globally. A major component in our approach is an information extraction framework which is composed of two challenging tasks. The first task is to detect unformatted text blocks automatically based on an unsupervised learning model. Identifying these useful text blocks through this learning model allows the generation of highly effective features for the next task which is text fragment extraction learning. The task of text fragment extraction learning is formulated as a domain adaptation model for text fragment classification. One advantage of our approach is that it can easily adapt to a large number of online job advertisements in different and new domains. Extensive experiments have been conducted to demonstrate the effectiveness and flexibility of our approach.

We have developed an unsupervised framework for simultaneously extracting and normalizing attributes of products from multiple Web pages originated from different sites. Our framework is designed based on a probabilistic graphical model that can model the page-independent content information and the page-dependent layout information of the text fragments in Web pages. One characteristic of our framework is that previously unseen attributes can be discovered from the clue contained in the layout format of the text fragments. Our framework tackles both extraction and normalization tasks by jointly considering the relationship between the content and layout information. Dirichlet process prior is employed leading to another advantage that the number of discovered product attributes is unlimited. An unsupervised inference algorithm based on variational method is presented. The semantics of the normalized attributes can be visualized by examining the term weights in the model. Our framework can be applied to a wide range of Web mining applications such as product matching and retrieval. We have conducted extensive experiments from four different domains consisting of over 300 Web pages from over 150 different Web sites, demonstrating the robustness and effectiveness of our framework.

We develop a novel framework that aims at automatically adapting previously learned information extraction knowledge from a source Web site to a new unseen target site in the same domain. Two kinds of features related to the text fragments from the Web documents are investigated. The first type of feature is called, a site-invariant feature. These features likely remain unchanged in Web pages from different sites in the same domain. The second type of feature is called a site-dependent feature. These features are different in the Web pages collected from different Web sites, while they are similar in the Web pages originating from the same site. In our framework, we derive the site-invariant features from previously learned extraction knowledge and the items previously collected or extracted from the source Web site. The derived site-invariant features will be exploited to automatically seek a new set of training examples in the new unseen target site. Both the site-dependent features and the site-invariant features of these automatically discovered training examples will be considered in the learning of new information extraction knowledge for the target site. We conducted extensive experiments on a set of real-world Web sites collected from three different domains to demonstrate the performance of our framework. For example, by just providing training examples from one online book catalog Web site, our approach can automatically extract information from ten different book catalog sites achieving an average precision and recall of 71.9% and 84.0% respectively without any further manual intervention.

We develop an unsupervised framework which can collaboratively extract information from multiple Web pages, as well as conduct feature mining tasks in a unified model. Our model allows tight interactions of the two tasks removing the unnecessary boundary between the two tasks. It is beneficial for both tasks since the decisions for information extraction and feature mining can be done in a coherent manner assigning solutions optimizing the quality of both tasks and at the same time eliminating the potential conflicts. Our approach is designed based on an undirected graphical model which can model the inter-dependence between the neighbouring tokens within the same Web page, as well as tokens in different Web pages. Multiple Web pages are considered under this model and the information can be extracted collectively. This design also leads to another characteristic of our framework in that it can conduct mining across Web pages simultaneously. We demonstrate the efficacy of our model by applying it to the important product feature mining application. Extensive experiments on real-world data have been conducted to evaluate our framework.

Online auction Web sites are fast changing, highly dynamic, and complex as they involve tremendous sellers and potential buyers, as well as a huge amount of items listed for bidding. We develop a two-phase framework which aims at mining and summarizing hot items from multiple auction Web sites to assist decision making. The objective of the first phase is to automatically extract the product features and product feature values of the items from the descriptions provided by the sellers. We design a HMM-based learning method to train an extended HMM model which can adapt to the unseen Web page from which the information is extracted. The goal of the second phase is to discover and summarize the hot items based on the extracted information. We formulate the hot item mining task as a semi-supervised learning problem and employ the graph mincuts algorithm to accomplish this task. The summary of the hot items is then generated by considering the frequency and the position of the product features being mentioned in the descriptions. We have conducted extensive experiments from several real-world auction Web sites to demonstrate the effectiveness of our framework.

We develop a probabilistic framework which can refine an existing ontology from a source Web site to new unseen sites. One characteristic of our framework is to consider several clues related to how an ontology influences the text content and the visual layout of the Web pages. The first clue is the text fragments regarding the content of the concepts previously collected or extracted from the source Web site. The second clue is the text fragments regarding the header labels of the concepts. The third clue is the visual layout of the text fragments regarding the content of the concepts and the header labels of the concepts in the unseen site. To harness the uncertainty involved in a rigorous manner, we formalize these clues by a generative model to represent the generation of text fragments regarding the concepts and the ontology corresponding to the Web page. Bayesian learning technique and expectation-maximization (EM) algorithm are employed to accomplish the task. Extensive experiments on several real-world Web sites from two different domains have been conducted to demonstrate the effectiveness of our framework.

We develop a probabilistic framework for adapting information extraction wrappers with new attribute discovery. Wrapper adaptation aims at automatically adapting a previously learned wrapper from the source Web site to a new unseen site for information extraction. One unique characteristic of our framework is that it can discover new or previously unseen attributes as well as headers from the new site. It is based on a generative model for the generation of text fragments related to attribute items and formatting data in a Web page. To solve the wrapper adaptation problem, we consider two kinds of information from the source Web site. The first kind of information is the extraction knowledge contained in the previously learned wrapper from the source Web site. The second kind of information is the previously extracted or collected items. We employ a Bayesian learning approach to automatically select a set of training examples for adapting a wrapper for the new unseen site. To solve the new attribute discovery problem, we develop a model which analyzes the surrounding text fragments of the attributes in the new unseen site. A Bayesian learning method is developed to discover the new attributes and their headers. EM technique is employed in both Bayesian learning models. We conducted extensive experiments from a number of real-world Web sites to demonstrate the effectiveness of our framework.

We develop a framework which can adapt previously learned information extraction knowledge from the source Web site to new unseen sites. Our framework also makes use of data items previously extracted or collected. Site invariant features are derived from the previously learned extraction knowledge and previously collected items. Multiple text mining methods are employed to automatically discover machine labeled training examples for the new site. Both site invariant and site dependent features of these machine labeled training examples are used to learn the new extraction knowledge. Extensive experiments on real-world Web sites have been conducted to demonstrate the effectiveness of our framework.

We propose a wrapper adaptation framework which aims at adapting a learned wrapper to an unseen Web site. It significantly reduces human effort in constructing wrappers. Our framework makes use of extraction rules previously discovered from a particular site to seek potential training example candidates for an unseen site. Rule generalization and text categorization are employed for finding suitable example candidates. Another feature of our approach is that it makes use of the previously discovered lexicon to classify good training examples automatically for the new site. We conducted extensive experiments to evaluate the quality of the extraction performance and the adaptability of our approach.