Opinion mining framework using proposed RB-bayes model for text classicationIJECEIAES
Information mining is a capable idea with incredible potential to anticipate future patterns and conduct. It alludes to the extraction of concealed information from vast data sets by utilizing procedures like factual examination, machine learning, grouping, neural systems and genetic algorithms. In naive baye’s, there exists a problem of zero likelihood. This paper proposed RB-Bayes method based on baye’s theorem for prediction to remove problem of zero likelihood. We also compare our method with few existing methods i.e. naive baye’s and SVM. We demonstrate that this technique is better than some current techniques and specifically can analyze data sets in better way. At the point when the proposed approach is tried on genuine data-sets, the outcomes got improved accuracy in most cases. RB-Bayes calculation having precision 83.333.
Controlling informative features for improved accuracy and faster predictions...Damian R. Mingle, MBA
Identification of suitable biomarkers for accurate prediction of phenotypic outcomes is a goal for personalized medicine. However, current machine learning approaches are either too complex or perform poorly.
For more information:
http://societyofdatascientists.com/controlling-informative-features-for-improved-accuracy-and-faster-predictions-in-omentum-cancer-models/?src=slideshare
The determination of complex underlying relationships between system parameters from simulated and/or recorded data requires advanced interpolating functions, also known as surrogates. The development of surrogates for such complex relationships often requires the modeling of high dimensional and non-smooth functions using limited information. To this end, the hybrid surrogate modeling paradigm, where different surrogate models are aggregated, offers a robust solution. In this paper, we develop a new high fidelity surro- gate modeling technique that we call the Reliability Based Hybrid Functions (RBHF). The RBHF formulates a reliable Crowding Distance-Based Trust Region (CD-TR), and adap- tively combines the favorable characteristics of different surrogate models. The weight of each contributing surrogate model is determined based on the local reliability measure for that surrogate model in the pertinent trust region. Such an approach is intended to ex- ploit the advantages of each component surrogate. This approach seeks to simultaneously capture the global trend of the function and the local deviations. In this paper, the RBHF integrates four component surrogate models: (i) the Quadratic Response Surface Model (QRSM), (ii) the Radial Basis Functions (RBF), (iii) the Extended Radial Basis Functions (E-RBF), and (iv) the Kriging model. The RBHF is applied to standard test problems. Subsequent evaluations of the Root Mean Squared Error (RMSE) and the Maximum Ab- solute Error (MAE), illustrate the promising potential of this hybrid surrogate modeling approach.
Optimal feature selection from v mware esxi 5.1 feature setijccmsjournal
A study of VMware ESXi 5.1 server has been carried out to find the optimal set of parameters which
suggest usage of different resources of the server. Feature selection algorithms have been used to extract
the optimum set of parameters of the data obtained from VMware ESXi 5.1 server using esxtop command.
Multiple virtual machines (VMs) are running in the mentioned server. K-means algorithm is used for
clustering the VMs. The goodness of each cluster is determined by Davies Bouldin index and Dunn index
respectively. The best cluster is further identified by the determined indices. The features of the best cluster
are considered into a set of optimal parameters.
Optimal Feature Selection from VMware ESXi 5.1 Feature Setijccmsjournal
A study of VMware ESXi 5.1 server has been carried out to find the optimal set of parameters which suggest usage of different resources of the server. Feature selection algorithms have been used to extract the optimum set of parameters of the data obtained from VMware ESXi 5.1 server using esxtop command. Multiple virtual machines (VMs) are running in the mentioned server. K-means algorithm is used for clustering the VMs. The goodness of each cluster is determined by Davies Bouldin index and Dunn index respectively. The best cluster is further identified by the determined indices. The features of the best cluster are considered into a set of optimal parameters.
Data analysis_PredictingActivity_SamsungSensorDataKaren Yang
- The document analyzes data from a study that tracked activity using smartphone sensors to predict activity type based on quantitative measurements.
- It builds random forest and support vector machine (SVM) models on a training data set and finds the random forest model has a lower error rate of 11%, making it the better predictive model.
- Variable importance analysis of the random forest model identifies 11 highly correlated variables as the most important predictors of activity type. Tuning the random forest model to use just these 11 variables results in a 16% error rate on a validation data set.
- Applying the tuned random forest model to a test data set achieves an error rate of 17%, confirming the 11 variables as key predictors of activity type
Building Predictive Models R_caret languagejaved khan
This document discusses the caret package in R, which contains tools for developing predictive models. It focuses on simplifying model training, tuning, and preprocessing across a variety of modeling techniques. The document illustrates the functionality using a real-world dataset on predicting chemical mutagenicity. It describes how the caret package is used to split data into training and test sets, preprocess data by identifying near zero-variance predictors, and build and tune models through resampling methods.
A Threshold Fuzzy Entropy Based Feature Selection: Comparative StudyIJMER
Feature selection is one of the most common and critical tasks in database classification. It
reduces the computational cost by removing insignificant and unwanted features. Consequently, this
makes the diagnosis process accurate and comprehensible. This paper presents the measurement of
feature relevance based on fuzzy entropy, tested with Radial Basis Classifier (RBF) network,
Bagging(Bootstrap Aggregating), Boosting and stacking for various fields of datasets. Twenty
benchmarked datasets which are available in UCI Machine Learning Repository and KDD have been
used for this work. The accuracy obtained from these classification process shows that the proposed
method is capable of producing good and accurate results with fewer features than the original
datasets.
Threshold benchmarking for feature ranking techniquesjournalBEEI
In prediction modeling, the choice of features chosen from the original feature set is crucial for accuracy and model interpretability. Feature ranking techniques rank the features by its importance but there is no consensus on the number of features to be cut-off. Thus, it becomes important to identify a threshold value or range, so as to remove the redundant features. In this work, an empirical study is conducted for identification of the threshold benchmark for feature ranking algorithms. Experiments are conducted on Apache Click dataset with six popularly used ranker techniques and six machine learning techniques, to deduce a relationship between the total number of input features (N) to the threshold range. The area under the curve analysis shows that ≃ 33-50% of the features are necessary and sufficient to yield a reasonable performance measure, with a variance of 2%, in defect prediction models. Further, we also find that the log2(N) as the ranker threshold value represents the lower limit of the range.
Sentiment Analysis: A comparative study of Deep Learning and Machine LearningIRJET Journal
This document compares sentiment analysis techniques using deep learning and machine learning. It summarizes previous work using various machine learning algorithms and deep learning methods for sentiment analysis. The document then outlines the approach taken in this study, which is to determine the best sentiment analysis results using either machine learning or deep learning techniques. It describes preprocessing the Rotten Tomatoes movie review dataset and creating text matrices before selecting models for classification. The goal is to get a generalized understanding of how sentiment analysis can be performed and which practices yield optimal results.
This document is a research proposal on attribute selection and representation for software defect prediction. The proposal discusses limitations in existing attribute selection methods and the importance of pre-processing data. It aims to propose a new attribute selection method that improves accuracy by addressing shortcomings, and to study appropriate classifiers. The methodology involves a literature review on pre-processing, attribute selection and classification methods. It will then propose and implement a new attribute selection process, compare it using different classifiers and pre-processing, and evaluate it against existing techniques in a technical report.
APPLYING GENETIC ALGORITHMS TO INFORMATION RETRIEVAL USING VECTOR SPACE MODEL IJCSEA Journal
Genetic algorithms are usually used in information retrieval systems (IRs) to enhance the information retrieval process, and to increase the efficiency of the optimal information retrieval in order to meet the users’ needs and help them find what they want exactly among the growing numbers of available information. The improvement of adaptive genetic algorithms helps to retrieve the information needed by the user accurately, reduces the retrieved relevant files and excludes irrelevant files. In this study, the researcher explored the problems embedded in this process, attempted to find solutions such as the way of choosing mutation probability and fitness function, and chose Cranfield English Corpus test collection on mathematics. Such collection was conducted by Cyrial Cleverdon and used at the University of Cranfield in 1960 containing 1400 documents, and 225 queries for simulation purposes. The researcher also used cosine similarity and jaccards to compute similarity between the query and documents, and used two proposed adaptive fitness function, mutation operators as well as adaptive crossover. The process aimed at evaluating the effectiveness of results according to the measures of precision and recall. Finally, the study concluded that we might have several improvements when using adaptive genetic algorithms.
Applying genetic algorithms to information retrieval using vector space modelIJCSEA Journal
The document describes a study that applied genetic algorithms to information retrieval using the vector space model. The study used an adaptive genetic algorithm approach with two proposed fitness functions (cosine and Jaccard's), adaptive crossover and mutation probabilities. Experimental results on a test corpus showed improvements in precision and recall compared to traditional approaches, with the proposed cosine fitness function performing best. Precision generally decreased as recall increased. The modifications made to the genetic algorithm and fitness functions led to better weighting of query terms and improved results.
This document summarizes a project to predict home insurance policy purchases from customer data using machine learning models. The authors explored a dataset of 260,753 customers to select meaningful features from 297 initial ones. They tested logistic regression, support vector machines, and gradient boosted trees on subsets of the data. Gradient boosted trees showed the best performance, with its accuracy on the test set increasing as more training data was used. The authors concluded this model was generalizing well to new data compared to the other algorithms tested.
A Novel Approach for Developing Paraphrase Detection System using Machine Lea...Rudradityo Saha
Plagiarism detection is difficult since there can be changes made to a sentence at several levels, namely, lexical, semantic, and syntactic level, to construct a paraphrased or plagiarized sentence posing as original. This project presents a novel Supervised Machine Learning Classification Paraphrase Detection System developed by conducting experiments using Microsoft Research Paraphrase (MSRP) Corpus and assessed on the same. The proposed paraphrase detection system has achieved comparable performance with existing paraphrase detection systems. The major contributions of this project are the utilization of a unique combination of lexical, semantic, and syntactic features, utilization of Shapley Additive Explanations (SHAP) Feature Importance Plots in XGBoost, and application of a soft voting classifier comprising of the top 3 performing standalone machine learning classifiers on the training dataset of MSRP Corpus. Another major contribution of the project is the finding that applying data augmentation techniques degrades the performance of machine learning classifiers.
A Modified KS-test for Feature SelectionIOSR Journals
This document proposes a modified Kolmogorov-Smirnov (KS) test-based feature selection algorithm. It begins with an overview of feature selection and its benefits. It then discusses two common feature selection approaches: filter and wrapper models. The document proposes a fast redundancy removal filter based on a modified KS statistic that utilizes class label information to compare feature pairs. It compares the proposed algorithm to other methods like Correlation Feature Selection (CFS) and KS-Correlation Based Filter (KS-CBF). The efficiency and effectiveness of the various methods are tested on standard classifiers. In most cases, the proposed approach achieved equal or better classification accuracy compared to using all features or the other algorithms.
Applying Genetic Algorithms to Information Retrieval Using Vector Space ModelIJCSEA Journal
Genetic algorithms are usually used in information retrieval systems (IRs) to enhance the information retrieval process, and to increase the efficiency of the optimal information retrieval in order to meet the users’ needs and help them find what they want exactly among the growing numbers of available information. The improvement of adaptive genetic algorithms helps to retrieve the information needed by the user accurately, reduces the retrieved relevant files and excludes irrelevant files. In this study, the researcher explored the problems embedded in this process, attempted to find solutions such as the way of choosing mutation probability and fitness function, and chose Cranfield English Corpus test collection on mathematics. Such collection was conducted by Cyrial Cleverdon and used at the University of Cranfield in 1960 containing 1400 documents, and 225 queries for simulation purposes. The researcher also used cosine similarity and jaccards to compute similarity between the query and documents, and used two proposed adaptive fitness function, mutation operators as well as adaptive crossover. The process aimed at evaluating the effectiveness of results according to the measures of precision and recall. Finally, the study concluded that we might have several improvements when using adaptive genetic algorithms.
Filter-Wrapper Approach to Feature Selection Using PSO-GA for Arabic Document...iosrjce
IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
This document presents a study that uses a filter-wrapper approach for feature selection in Arabic document classification using Naive Bayes Multinomial. The study uses Particle Swarm Optimization (PSO) as the filter method to initially reduce features, followed by a Genetic Algorithm (GA) as the wrapper method to further optimize the features. The approach is tested on 478 Arabic documents classified into 7 categories. Results show the proposed NBM-PSO-GA approach achieves a classification accuracy of 90.2%, higher than NBM alone at 81.8% or NBM with just PSO filtering at 83.9%.
This document presents a feature clustering algorithm to reduce the dimensionality of feature vectors for text classification. The algorithm groups words in documents into clusters based on similarity, with each cluster characterized by a membership function. Words not similar to existing clusters form new clusters. This avoids specifying features in advance and the need for trial and error. Experimental results showed the method can classify text faster and with better extracted features than other methods.
Similar to Data science and visualization MODULE 3 FG&FS (20)
Social media management system project report.pdfKamal Acharya
The project "Social Media Platform in Object-Oriented Modeling" aims to design
and model a robust and scalable social media platform using object-oriented
modeling principles. In the age of digital communication, social media platforms
have become indispensable for connecting people, sharing content, and fostering
online communities. However, their complex nature requires meticulous planning
and organization.This project addresses the challenge of creating a feature-rich and
user-friendly social media platform by applying key object-oriented modeling
concepts. It entails the identification and definition of essential objects such as
"User," "Post," "Comment," and "Notification," each encapsulating specific
attributes and behaviors. Relationships between these objects, such as friendships,
content interactions, and notifications, are meticulously established.The project
emphasizes encapsulation to maintain data integrity, inheritance for shared behaviors
among objects, and polymorphism for flexible content handling. Use case diagrams
depict user interactions, while sequence diagrams showcase the flow of interactions
during critical scenarios. Class diagrams provide an overarching view of the system's
architecture, including classes, attributes, and methods .By undertaking this project,
we aim to create a modular, maintainable, and user-centric social media platform that
adheres to best practices in object-oriented modeling. Such a platform will offer users
a seamless and secure online social experience while facilitating future enhancements
and adaptability to changing user needs.
Software Engineering and Project Management - Introduction to Project ManagementPrakhyath Rai
Introduction to Project Management: Introduction, Project and Importance of Project Management, Contract Management, Activities Covered by Software Project Management, Plans, Methods and Methodologies, some ways of categorizing Software Projects, Stakeholders, Setting Objectives, Business Case, Project Success and Failure, Management and Management Control, Project Management life cycle, Traditional versus Modern Project Management Practices.
OCS Training Institute is pleased to co-operate with
a Global provider of Rig Inspection/Audits,
Commission-ing, Compliance & Acceptance as well as
& Engineering for Offshore Drilling Rigs, to deliver
Drilling Rig Inspec-tion Workshops (RIW) which
teaches the inspection & maintenance procedures
required to ensure equipment integrity. Candidates
learn to implement the relevant standards &
understand industry requirements so that they can
verify the condition of a rig’s equipment & improve
safety, thus reducing the number of accidents and
protecting the asset.
How to Manage Internal Notes in Odoo 17 POSCeline George
In this slide, we'll explore how to leverage internal notes within Odoo 17 POS to enhance communication and streamline operations. Internal notes provide a platform for staff to exchange crucial information regarding orders, customers, or specific tasks, all while remaining invisible to the customer. This fosters improved collaboration and ensures everyone on the team is on the same page.
Exploring Deep Learning Models for Image Recognition: A Comparative Reviewsipij
Image recognition, which comes under Artificial Intelligence (AI) is a critical aspect of computer vision,
enabling computers or other computing devices to identify and categorize objects within images. Among
numerous fields of life, food processing is an important area, in which image processing plays a vital role,
both for producers and consumers. This study focuses on the binary classification of strawberries, where
images are sorted into one of two categories. We Utilized a dataset of strawberry images for this study; we
aim to determine the effectiveness of different models in identifying whether an image contains
strawberries. This research has practical applications in fields such as agriculture and quality control. We
compared various popular deep learning models, including MobileNetV2, Convolutional Neural Networks
(CNN), and DenseNet121, for binary classification of strawberry images. The accuracy achieved by
MobileNetV2 is 96.7%, CNN is 99.8%, and DenseNet121 is 93.6%. Through rigorous testing and analysis,
our results demonstrate that CNN outperforms the other models in this task. In the future, the deep
learning models can be evaluated on a richer and larger number of images (datasets) for better/improved
results.
A brief introduction to quadcopter (drone) working. It provides an overview of flight stability, dynamics, general control system block diagram, and the electronic hardware.
Profiling of Cafe Business in Talavera, Nueva Ecija: A Basis for Development ...IJAEMSJORNAL
This study aimed to profile the coffee shops in Talavera, Nueva Ecija, to develop a standardized checklist for aspiring entrepreneurs. The researchers surveyed 10 coffee shop owners in the municipality of Talavera. Through surveys, the researchers delved into the Owner's Demographic, Business details, Financial Requirements, and other requirements needed to consider starting up a coffee shop. Furthermore, through accurate analysis, the data obtained from the coffee shop owners are arranged to derive key insights. By analyzing this data, the study identifies best practices associated with start-up coffee shops’ profitability in Talavera. These findings were translated into a standardized checklist outlining essential procedures including the lists of equipment needed, financial requirements, and the Traditional and Social Media Marketing techniques. This standardized checklist served as a valuable tool for aspiring and existing coffee shop owners in Talavera, streamlining operations, ensuring consistency, and contributing to business success.
Understanding Cybersecurity Breaches: Causes, Consequences, and PreventionBert Blevins
Cybersecurity breaches are a growing threat in today’s interconnected digital landscape, affecting individuals, businesses, and governments alike. These breaches compromise sensitive information and erode trust in online services and systems. Understanding the causes, consequences, and prevention strategies of cybersecurity breaches is crucial to protect against these pervasive risks.
Cybersecurity breaches refer to unauthorized access, manipulation, or destruction of digital information or systems. They can occur through various means such as malware, phishing attacks, insider threats, and vulnerabilities in software or hardware. Once a breach happens, cybercriminals can exploit the compromised data for financial gain, espionage, or sabotage. Causes of breaches include software and hardware vulnerabilities, phishing attacks, insider threats, weak passwords, and a lack of security awareness.
The consequences of cybersecurity breaches are severe. Financial loss is a significant impact, as organizations face theft of funds, legal fees, and repair costs. Breaches also damage reputations, leading to a loss of trust among customers, partners, and stakeholders. Regulatory penalties are another consequence, with hefty fines imposed for non-compliance with data protection regulations. Intellectual property theft undermines innovation and competitiveness, while disruptions of critical services like healthcare and utilities impact public safety and well-being.
Unblocking The Main Thread - Solving ANRs and Frozen FramesSinan KOZAK
In the realm of Android development, the main thread is our stage, but too often, it becomes a battleground where performance issues arise, leading to ANRS, frozen frames, and sluggish Uls. As we strive for excellence in user experience, understanding and optimizing the main thread becomes essential to prevent these common perforrmance bottlenecks. We have strategies and best practices for keeping the main thread uncluttered. We'll examine the root causes of performance issues and techniques for monitoring and improving main thread health as wel as app performance. In this talk, participants will walk away with practical knowledge on enhancing app performance by mastering the main thread. We'll share proven approaches to eliminate real-life ANRS and frozen frames to build apps that deliver butter smooth experience.
Development of Chatbot Using AI/ML Technologiesmaisnampibarel
The rapid advancements in artificial intelligence and natural language processing have significantly transformed human-computer interactions. This thesis presents the design, development, and evaluation of an intelligent chatbot capable of engaging in natural and meaningful conversations with users. The chatbot leverages state-of-the-art deep learning techniques, including transformer-based architectures, to understand and generate human-like responses.
Key contributions of this research include the implementation of a context- aware conversational model that can maintain coherent dialogue over extended interactions. The chatbot's performance is evaluated through both automated metrics and user studies, demonstrating its effectiveness in various applications such as customer service, mental health support, and educational assistance. Additionally, ethical considerations and potential biases in chatbot responses are examined to ensure the responsible deployment of this technology.
The findings of this thesis highlight the potential of intelligent chatbots to enhance user experience and provide valuable insights for future developments in conversational AI.
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Data Wrangling in R
1. Dplyr-fundamental data-munging R bundle. Tool for Supreme Data Framing.Particularly useful
for the operation of categories of data.
2. Purrr-good for listing and error-checking features.
3. Splitstackshape-an oldie, but a goldie. Great for the shaping of full
4. Splitstackshape-an oldie, but a goldie. Perfect for shaping complex data sets and making
visualization easier.
5. JSOnline-a simple and quick scanning device.
6. Magrittr-good for wrangling scattered sets and putting them in a more cohesive shape.
8. FEATURE GENERATION
8.1 INTRODUCTION
The 2004 Text Retrieval Conference (TREC) Genomics Track was divided into two main tasks:
categorization and ad hoc retrieval. The categorization task consisted of a document triage subtask
and an annotation subtask to detect the presence of evidence in the document for each of the three
main Gene Ontology (GO) code hierarchies. Our work focused on the document triage subtask. We
also participated in the ad hoc retrieval task.
8.2 BACKGROUND
The classification of documents is a common problem in biomedicine. Training a support vector
machine (SVM) on vectors generated from stemmed and/or stopped document word counts has
proven to be a simple and generally efficient method (Yeh et al., 2003).
However, we agreed that the triage issue posed here had some distinctive features that would entail a
modification of the standard approach. First, it was understood that the number of true positive
results in both the training and the test set was low, about 6-7%. Second, the utility function chosen
as the record metric was heavily weighted to reward recall and not precision.
This was based on an overview of the existing working procedures of the annotators at the Mouse
Genome Institute (MGI) and an estimate of how they actually view false negative and false positive
classifications. The official utility feature weights a false negative as 20 times more extreme than a
false positive. Using this metric, the existing work procedure of MGI, which reads all the documents
in the test set, has a value of 0.25. In fact, the training and evaluation samples were not randomly
drawn from the same survey, but rather obtained from documents released in two consecutive years.
While this is a more practical simulation of the framework as it would be applied to MGI, it poses
the question of how well the features derived from one year of literature reflect the literature of
subsequent years. As a result of these problems, our approach included a rich collection of features,
statistically dependent selection of features, multiple classifiers, and an analysis of how well the
features extracted from the 2002 corpus reflected the documents in the 2003 corpus.
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8.3 SYSTEM AND METHODS
We have tackled the question of triage in four stages: the generation of features, the selection of
features, the collection and training of classifiers and, finally, the classification of test documents.
Only the training package was used to complete the first three measures. The final step in collecting
the test was taken to produce the results submitted. During the development of the program, we used
ten-fold cross-validation on the training set to compare approaches and set program parameters. It
included the execution of the first two phases of the entire training series. Then 90% of the training
data was used to train the classifiers, which were then applied to the remaining 10% of the training
data. This has been repeated nine times, so that all the training data has been classified once. The
findings were then aggregated to compute cross-validation metrics for the training corpus. Figure 17
displays this phase diagrammatically.
Figure 17: Step-wise approach to test classification
1. Feature generation
The full text corpus with SGML mark-up offered an opportunity to explore the use of several types
of features. While many text classification methods view text as a "bag-of-words," we have opted to
use the information contained in the SGML mark-up to generate unique section type features. Since
we merged features that could occur several times in a single document with features that could only
occur once, after some initial testing, we decided to view each feature as binary, that is, each feature
was either present in a document or absent. One type of function we created consisted of pairs of
section names and stemmed words using the Porter stemming algorithm. Upon applying a stop list of
the 300 most common English words, the individual parts of the text collected were coded to include
abstract sections, body paragraphs, captions and section titles. We have created a similar hybrid
section, stammedword features, using the stopped and stammed section title in conjunction with the
stopped and stammed words in the named section. In addition, we have downloaded the related
MEDLINE documents from PubMed. For each post, the corresponding MeSH headings have been
extracted. We included MeSH-based features based on the full MeSH headings, the MeSH main
headings and the MeSH subheadings. Finally, we included features based on details in the reference
section of each text. The key author of each reference was taken as a form of attribute. We also
Feature Generation
Classifier Selection & Training
Feature Selection
Document Classification
Test Corpus
Training Corpus
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included a long form of references as a feature sort, including the primary author, journal name,
length, year, and page number. Running the feature generation process on a full set of 5837 training
documents created over 100,000 potentially useful features along with a count of the number of
documents containing each feature.
2. Feature selection
We have opted to use the Chi-square selection method to pick the features that best differentiated
between positive and negative documents in the training corpus. The 2x2 Chisquare table is
constructed as shown in Table 1, using the number of documents obtained in the previous stage.
During machine tuning, an alpha value of 0.025 was found to produce the best results. Using this
value as a cut-off, 1885 features were selected as the most important. The number and type of each
feature found significant and used in the following steps are shown in Table 2.
3. Classifier selection and training
Three specific classifiers were applied to the problem: Naive Bayes, SVM, and Voting Perceptron.
Although it is widely thought that the best classifiers are based on Vapnik's SVM method (Vapnik,
2000), the distinctive aspects of the current classification issue discussed above inspired us to apply
three different classifiers. By using the same feature set with each of the classifiers, this helped us to
compare the efficiency of the classifier algorithms with the particular requirements of the triage
function.
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Neither Naive Bayes nor the implementation of the SVM we used, SVMLight (Joachims, 2004),
offered adequate means to change the low frequency of positive and the high value of true positive
relative to false positive. We used our own implementation for Naive Bayes. Naive Bayes sets a
classification probability threshold that can be used to switch between precision and recall.
Nonetheless, this is an indirect form of compensation, and in practice, for this task of classification,
we found that raising the likelihood threshold did not have a meaningful impact.
We fully expected SVMLight to perform better than Naive Bayes, as it contained a cost factor
parameter that could be changed to require unequal penalties for false positives and false negatives.
Nevertheless, we found that the amount of impact of this parameter was limited and insufficient to
account for the 20 difference between the cost of false positives and negatives. Since neither Naive
Bayes nor one of the most common SVM implementations addressed our requirements, something
else was required.
An analysis of the classification literature reveals considerable progress in adjusting the classical
Rosenblatt Perceptron algorithm (Rosenblatt, 1958) to achieve efficiency at or near SVM for several
problems. One algorithm in particular, the Voting Perceptron algorithm (Freund and Schapire, 1999),
has quite good efficiency, is very fast and easy to implement. Although the algorithm as published
does not provide a way to account for asymmetric false positive and negative penalties, we have
made a change to the algorithm that does. Perceptron is basically an equation for a linear
combination of the values of the set of features.
For every element in the feature set, there is one term in the perceptron plus an optional bias phrase.
The document is defined by taking the dot product of the document's feature vector with the
perceptron and adding it to the bias word. When the result is greater than zero, the document is
classified as positive, if it is less than or equal to zero, then the document is classified as negative.
The original algorithm of Rosenblatt trained the perceptron by applying it to each sample in the
training results.
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If the sample was wrongly labeled, the perceptron was changed by adding or subtracting the sample
back into the perceptron, adding when the sample was a true positive, and subtracting when the
sample was a true negative. Over a large number of training samples, the perceptron converges on a
solution that better approximates the distinction between positive and negative documents in the
training package. Freund and Schapire improved the performance of the perceptron by modifying the
algorithm to produce a series of perceptrons, each of which makes a prediction about the class of
each document and receives a number of "votes" depending on how many documents the perceptron
has correctly classified in the training set.
The class with the most votes is the class allocated to the paper. Our extension to this algorithm is
based on a specific modification of the perceptron learning rate for false negatives and false
positives. Although incorrectly classified samples are directly added or subtracted back to the
perceptron in the typical implementation, we first multiply the sample by a factor known as the
learning rate. In addition, we use separate learning thresholds for false positives and false negatives.
Given the concept of the utility function, we predicted that the optimal learning rate for false
negatives will be around 20 times that for false positives.
In reality, that's what we noticed during the training. We used 20.0 for false negatives, and 1.0 for
false positives. The training corpus was applied to each of the three classifiers. Ten-fold cross-
validation has been used to optimize all free parameters. The Naive Bayes classifier had one free
parameter, the threshold for the probability classification. It was left to the default value of 0.50. The
selected SVM-Light classifier settings used a linear kernel and a cost factor of 20.0. The Voting
Perceptron classifier was used with a linear kernel and the learning rate was given above. For each of
the three approaches, a trained classifier model was developed.
4. Classification of test documents
Eventually, the test corpus was added to the models developed by the Naive Bayes, SVM and Voting
Perceptron classifiers. It's done in two steps. The documents in the study sample were first examined
for the presence or absence of significant features observed during the selection process. This has
generated a vector function for each test paper. The documents were then categorized by applying
each of the three qualified classifiers.
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5. Evaluation of conceptualdrift
One critical problem in applying text classification systems to documents of interest to curators and
annotators is how well the available training data reflect the documents to be categorized. When
classifying the biomedical text, the available training manuals must have been written in advance of
the text to be categorized. However, because of its very existence, the field of science shifts over
time, as does the vocabulary used to explain it.
How easily written science literature changes has a direct effect on the creation of biomedical text
classification systems in terms of how the features are developed and chosen, how much the systems
need to be re-trained, how much training is required, and the overall performance that can be
expected from such systems can be affected. Throughout biomedical literature, we decided to begin
to understand this significant topic of conceptual drift.
In order to determine how well the features chosen from the training collection reflected the
information that was relevant in classifying the document in the test collection, we took additional
steps in producing the features and selecting the test collection. The exact same method and
parameters were used for the collection of tests as for the collection of testing. We then calculated
how well the training collection feature set reflected the test collection feature set by the
computational similarity metrics between the two sets (Dunham, 2003).
9. FEATURE SELECTION ALGORITHMS
Feature selection is also called selection of variables or selection of attributes.
It is the automated selection of attributes in your data (such as columns in tabular data) that are most
important to the issue of predictive modeling that you are working on.
"Feature Selection... is the method of selecting a subset of the applicable features for use in model
construction.”
The selection of features is distinct from the reduction of dimensionality. Both methods aim to
minimize the number of attributes in the dataset, but the dimensional reduction approach does so by
introducing new combinations of attributes, while the feature selection methods include and remove
attributes present in the data without modifying them.
Examples of dimensionality reduction methods include Principal Component Analysis, Singular
Value Decomposition and Sammon’sMapping.
“Feature selection is itself useful, but it mostly acts as a filter, muting out features that aren’t useful
in addition to your existing features”.
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9.1 The Problem the Feature Selection Solves
Feature selection methods allow you to build an effective predictive model in your task. We support
you by selecting features that will give you as good or better accuracy while needing less data.
Feature selection approaches may be used to recognize and delete unwanted, obsolete and redundant
attributes from data that do not contribute to the accuracy of the predictive model or can potentially
reduce the accuracy of the model.
Fewer attributes are preferable because they reduce the complexity of the model, and a simpler
model is easier to understand and describe.
The goal of variable selection is threefold:
1. to enhance predictor efficiency,
2. to provide quicker and more cost-effective predictors,
3. and to provide a better understanding of the underlying process that generated the data.
9.2 Feature Selection Algorithms
There are three general classes of feature selection algorithms:
1. Filter methods,
2. Wrapper methods,
3. Embedded methods.
Filter Methods
Filter feature selection approaches use a statistical test to assign a score to each element. The features
are ranked by the score and either selected to be stored or deleted from the dataset. Methods are
mostly univariate and consider the function separately or in relation to the dependent variable.
Examples of some of the filter methods include the Chi squared test, information gain and correlation
coefficient ratings.
Wrapper Methods
Wrapper approaches consider the collection of a set of features as a search problem where various
combinations are planned, evaluated and compared to other combinations. A predictive algorithm
used to test a combination of features and give a score based on the accuracy of the formula.
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The search process may be methodical, such as a best-first search, stochastic, such as a random hill-
climbing algorithm, or heuristics, such as forward and backward passes, may be used to add and
remove features.
An example if the wrapper approach is a recursive elimination algorithm.
Embedded Methods
Embedded methods learn which features better contribute to the accuracy of the model when the
model is being built. Regularization methods are the most common type of embedded feature
selection methods. Regularization methods are often called penalization methods that apply
additional constraints to the design of a predictive algorithm (such as a regression algorithm) that
moves the model towards lower complexity (lower coefficients). Examples of regularization
algorithms include LASSO, Elastic Net and Ridge Regression.
9.3 How to Choose a Feature Selection Method for Machine Learning
Feature selection is a method that reduces the number of input variables when designing a predictive
model. It is beneficial to reduce the number of input variables, both to reduce the computational cost
of modeling and, in some cases, to increase the efficiency of the model.
Feature-based feature selection approaches include analyzing the relationship between each input
variable and the target variable using statistics and choosing those input variables that have the best
relationship with the target variable. These methods can be fast and efficient, although the choice of
statistical measures depends on the data type of both input and output variables. As such, it may be
difficult for a machine learning practitioner to choose an appropriate statistical measure for a data set
when choosing filter-based apps.
1. Feature Selection Methods
Feature selection approaches are designed to reduce the number of input variables to those deemed
most useful for the model in order to predict the target variable.
Some predictive modeling problems have a large number of variables that can slow down the
creation and training of models and require a large amount of machine memory. In addition, the
output of certain models can be degraded by adding input variables that are not important to the
target variable.
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There are two major types of feature selection algorithms: the wrapper method and the filter method.
1. Wrapper Feature Selection Methods.
2. Filter Feature Selection Methods.
1. Wrapper feature selection approaches generate several models with various input features
subsets and pick those features that result in the best output model according to the performance
metric. These methods are not concerned with variable types, although they can be
computationally costly. RFE is a good example of a method for selecting a wrapper function.
Wrapper methods test several models using procedures that add and/or extract predictors to find
the optimum combination that maximizes model efficiency.
2. Filter feature selection approaches use statistical techniques to test the relationship between
each input variable and the target variable, and these scores are used as the basis for selecting
(filtering) the input variables that will be used in the model. Filter methods test the importance of
predictors outside the predictive models, and then only model predictors that pass any criterion.
Correlation style statistical measurements between input and output variables are widely used as
the basis for filter function selection. As such, the choice of statistical measures is highly
dependent on variable data types. Popular data types include numerical (such as height) and
categorical (such as label), although each can be further subdivided as integer and floating point
for numerical variables, and boolean, ordinal, or nominal for categorical variables.