As program comprehension is a vast research area, it is necessary to get an overview of its rising and falling trends. We performed an n-gram frequency analysis on titles, abstracts and keywords of 1885 articles about program comprehension from the years 2000–2014. According to this analysis, the most rising trends are feature location and open source systems, the most falling ones are program slicing and legacy systems.
A similar trend analysis @cite_9 was performed on the papers from nine Mining Software Repositories conferences. The authors analyzed another, albeit related, research field. Our study is methodologically inspired by this paper in some aspects, particularly the idea of n-gram frequency analysis. However, our approach differs in many ways. For example, the authors analyzed only nine years of one particular conference, while we performed a web search for the keywords. On the other hand, they analyzed full texts, while we only processed the metadata. An n-gram query language syntax was inspired by Google Ngram Viewer @cite_4 . We also considered directly using this tool for our study since it offers a text corpus many orders of magnitude larger than ours. While the time period is broader, too, it does not include the last two years. Furthermore, it is not specialized to computer science and the corpus consists of books, which are less suitable for latest trend analysis than research articles. It is also possible to analyze Q &A (question and answer) sites such as Stack Overflow to find out trending topics. In @cite_8 , a technique called latent Ditrichlet allocation @cite_7 was used to recover topics from natural language texts.
@cite_9 @cite_4 @cite_7 @cite_8
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We propose a new unsupervised learning technique for extracting information from large text collections. We model documents as if they were generated by a two-stage stochastic process. Each author is represented by a probability distribution over topics, and each topic is represented as a probability distribution over words for that topic. The words in a multi-author paper are assumed to be the result of a mixture of each authors' topic mixture. The topic-word and author-topic distributions are learned from data in an unsupervised manner using a Markov chain Monte Carlo algorithm. We apply the methodology to a large corpus of 160,000 abstracts and 85,000 authors from the well-known CiteSeer digital library, and learn a model with 300 topics. We discuss in detail the interpretation of the results discovered by the system including specific topic and author models, ranking of authors by topic and topics by author, significant trends in the computer science literature between 1990 and 2002, parsing of abstracts by topics and authors and detection of unusual papers by specific authors. An online query interface to the model is also discussed that allows interactive exploration of author-topic models for corpora such as CiteSeer. This dissertation investigates the role of contextual information in the automated retrieval and display of full-text documents, using robust natural language processing algorithms to automatically detect structure in and assign topic labels to texts. Many long texts are comprised of complex topic and subtopic structure, a fact ignored by existing information access methods. I present two algorithms which detect such structure, and two visual display paradigms which use the results of these algorithms to show the interactions of multiple main topics, multiple subtopics, and the relations between main topics and subtopics. The first algorithm, called TextTiling , recognizes the subtopic structure of texts as dictated by their content. It uses domain-independent lexical frequency and distribution information to partition texts into multi-paragraph passages. The results are found to correspond well to reader judgments of major subtopic boundaries. The second algorithm assigns multiple main topic labels to each text, where the labels are chosen from pre-defined, intuitive category sets; the algorithm is trained on unlabeled text. A new iconic representation, called TileBars uses TextTiles to simultaneously and compactly display query term frequency, query term distribution and relative document length. This representation provides an informative alternative to ranking long texts according to their overall similarity to a query. For example, a user can choose to view those documents that have an extended discussion of one set of terms and a brief but overlapping discussion of a second set of terms. This representation also allows for relevance feedback on patterns of term distribution. TileBars display documents only in terms of words supplied in the user query. For a given retrieved text, if the query words do not correspond to its main topics, the user cannot discern in what context the query terms were used. For example, a query on contaminants may retrieve documents whose main topics relate to nuclear power, food, or oil spills. To address this issue, I describe a graphical interface, called Cougar , that displays retrieved documents in terms of interactions among their automatically-assigned main topics, thus allowing users to familiarize themselves with the topics and terminology of a text collection. The trends in a research field, especially changes in the features over the years, are subjects of interest for many researchers. This paper reports an exploratory analysis of the changes of research topics in an academic field. The target data of the analysis are the author-keywords included in papers presented at a series of academic conferences, IEEE International Conference on Data Mining (ICDM). The analysis process consists of three phases: (1) frequency of keywords, (2) appearance of keywords in papers, and (3) relationships among keywords. In phase 1, bar charts were used to observe the ranking of frequencies. In phases 2 and 3, anchored maps were adopted. The anchored maps are based on the spring-embedder model, but they provide viewpoints by using fixed "anchors." The analysis process revealed the major topics in the field of data mining and some changes in the relationships among topics. In this work, we discover the daily location-driven routines that are contained in a massive real-life human dataset collected by mobile phones. Our goal is the discovery and analysis of human routines that characterize both individual and group behaviors in terms of location patterns. We develop an unsupervised methodology based on two differing probabilistic topic models and apply them to the daily life of 97 mobile phone users over a 16-month period to achieve these goals. Topic models are probabilistic generative models for documents that identify the latent structure that underlies a set of words. Routines dominating the entire group's activities, identified with a methodology based on the Latent Dirichlet Allocation topic model, include “going to work late”, “going home early”, “working nonstop” and “having no reception (phone off)” at different times over varying time-intervals. We also detect routines which are characteristic of users, with a methodology based on the Author-Topic model. With the routines discovered, and the two methods of characterizing days and users, we can then perform various tasks. We use the routines discovered to determine behavioral patterns of users and groups of users. For example, we can find individuals that display specific daily routines, such as “going to work early” or “turning off the mobile (or having no reception) in the evenings”. We are also able to characterize daily patterns by determining the topic structure of days in addition to determining whether certain routines occur dominantly on weekends or weekdays. Furthermore, the routines discovered can be used to rank users or find subgroups of users who display certain routines. We can also characterize users based on their entropy. We compare our method to one based on clustering using K-means. Finally, we analyze an individual's routines over time to determine regions with high variations, which may correspond to specific events.