29,094 research outputs found
Sentiment Analysis using an ensemble of Feature Selection Algorithms
To determine the opinion of any person experiencing any services or buying any product, the usage of Sentiment Analysis, a continuous research in the field of text mining, is a common practice. It is a process of using computation to identify and categorize opinions expressed in a piece of text. Individuals post their opinion via reviews, tweets, comments or discussions which is our unstructured information. Sentiment analysis gives a general conclusion of audits which benefit clients, individuals or organizations for decision making. The primary point of this paper is to perform an ensemble approach on feature reduction methods identified with natural language processing and performing the analysis based on the results. An ensemble approach is a process of combining two or more methodologies. The feature reduction methods used are Principal Component Analysis (PCA) for feature extraction and Pearson Chi squared statistical test for feature selection. The fundamental commitment of this paper is to experiment whether combined use of cautious feature determination and existing classification methodologies can yield better accuracy
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REST: A thread embedding approach for identifying and classifying user-specified information in security forums
REST: A Thread Embedding Approach for Identifying and Classifying User-specified Information in Security Forums
How can we extract useful information from a security forum? We focus on
identifying threads of interest to a security professional: (a) alerts of
worrisome events, such as attacks, (b) offering of malicious services and
products, (c) hacking information to perform malicious acts, and (d) useful
security-related experiences. The analysis of security forums is in its infancy
despite several promising recent works. Novel approaches are needed to address
the challenges in this domain: (a) the difficulty in specifying the "topics" of
interest efficiently, and (b) the unstructured and informal nature of the text.
We propose, REST, a systematic methodology to: (a) identify threads of interest
based on a, possibly incomplete, bag of words, and (b) classify them into one
of the four classes above. The key novelty of the work is a multi-step weighted
embedding approach: we project words, threads and classes in appropriate
embedding spaces and establish relevance and similarity there. We evaluate our
method with real data from three security forums with a total of 164k posts and
21K threads. First, REST robustness to initial keyword selection can extend the
user-provided keyword set and thus, it can recover from missing keywords.
Second, REST categorizes the threads into the classes of interest with superior
accuracy compared to five other methods: REST exhibits an accuracy between
63.3-76.9%. We see our approach as a first step for harnessing the wealth of
information of online forums in a user-friendly way, since the user can loosely
specify her keywords of interest
One-Class Classification: Taxonomy of Study and Review of Techniques
One-class classification (OCC) algorithms aim to build classification models
when the negative class is either absent, poorly sampled or not well defined.
This unique situation constrains the learning of efficient classifiers by
defining class boundary just with the knowledge of positive class. The OCC
problem has been considered and applied under many research themes, such as
outlier/novelty detection and concept learning. In this paper we present a
unified view of the general problem of OCC by presenting a taxonomy of study
for OCC problems, which is based on the availability of training data,
algorithms used and the application domains applied. We further delve into each
of the categories of the proposed taxonomy and present a comprehensive
literature review of the OCC algorithms, techniques and methodologies with a
focus on their significance, limitations and applications. We conclude our
paper by discussing some open research problems in the field of OCC and present
our vision for future research.Comment: 24 pages + 11 pages of references, 8 figure
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