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-1
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0answers
18 views

Is it possible to use WEKA in a web based application? [on hold]

I am building a web based text mining application. For a word that user enters, the application has to: search it in google gather the documents pre-process by using Bag of words model cluster ...
2
votes
1answer
35 views

Explaining the steps of a visualization tool

this is my first post on CrossValidated. I've done, for academic purpose, a web tool doing this process: web scraping from various sites pre-process the responses (cleaning, error and redundance ...
0
votes
0answers
10 views

Measuring efficiency of hierarchical clustering alone

I have designed a model which uses hierarchical clustering to predict user habit, by either stating number (0) or number (1) in a specific context. It uses a three stage approach with 4d data (n ...
0
votes
0answers
10 views

What is the measurement scale of the Reciprocal Rank metric?

The reciprocal rank (RR) metric is often used to measure to what extent ranking approaches are able to return relevant items in the topmost positions of the list of results. It is computed as follows: ...
3
votes
2answers
110 views

Vector Space Model for Online News Clustering

I am trying to automatically cluster news articles based on their content. I need this algorithm to be online and simply group news articles related to the same story as they arrive. The common ...
0
votes
0answers
23 views

Typical range of values for TFIDF

I am working on a text corpus. Each line contains between 10 and 50 words. There are around 25 000 words in the whole text and 1 000 000 lines. I turned this corpus into its tf-idf representation. I ...
0
votes
0answers
31 views

Information retrieval from strings using neural network

I am dealing with input strings that have max length of 200 characters, they are the USSD popup msgs and the SMS text strings on android smart phones extracted as and when they appear via an android ...
1
vote
2answers
128 views

What is the best algorithm to find similar text documents?

I have many text documents and I would like to find similar documents to each document within my data set. Is Latent Dirichlet Allocation (LDA) the best way to do that, or are there other algorithms ...
-1
votes
1answer
26 views

Data mining : I want to automate data scrapping process in ruby. Which approach would be better. Supervised or unsupervised?

I've read that the problem with supervised approach is it fails to generalize if the structure of web page changes. But sites rarely change their structure. Problem with unsupervised is it will ...
0
votes
1answer
112 views

Clustering structured data: Assessing the similarity of documents that appear in tree structure

Usually when performing text document clustering, similarities across documents are assessed based on the lexical content of documents. But, in my problem, I wish to consider both the lexical content ...
6
votes
1answer
120 views

Why does Lucene IDF have a seemingly additional +1?

From the Lucene docs $\text{IDF} = 1 + \log\left(\frac{\text{numDocs}}{\text{docFreq}+1}\right)$ In other references (i.e. wikipedia), IDF is typically calculated as ...
1
vote
1answer
40 views

Average precision when not all the relevant documents are found

I can't find on the Internet a proper source that explains this. I have built a search engine that for a particular query retrieves 5 relevant document out of the 10 relevant documents. When I ...
3
votes
0answers
32 views

Heuristics streaming data matching

I have an index composed by thousands of documents. Slightly modified copies of those documents are sent to my application in small chunks, and I need to check, from those chunks, which document has ...
0
votes
0answers
26 views

An IR evalualuation metric that only measures the rank of results?

I am working on a little text clustering problem, and trying to figure out how to evaluate the results. I came up with the following idea that I though fits pretty well with the specifics of the ...
0
votes
0answers
38 views

Understanding the Precision-Recall breakeven point in ranking

Consider an IR system that retrieves all document and rank them in order of relevance. Now, we can calculate Precision and Recall at each rank. Does the breakeven point (recall=precision) always ...
0
votes
0answers
34 views

Test statistics in IR (t-test vs Wilcoxon vs signed test)

I have just read this paper about different test statistics one could use in Information Retrieval (IR), discussing whether Wilcoxon, Sign-test or Student t-test would be more reliable for comparing ...
0
votes
1answer
34 views

Calculation of Cosine Similarity using LSA

I am getting negative cosine similarity value between two documents in Latent Semantic analysis. How should it be treated?
0
votes
0answers
17 views

Can using of Weight function in Latent Semantic Analysis increase the efficiency of the technique?

What type of combination of local & global weight function and what would be the length of the document which can actually increase the efficiency of the LSA.
0
votes
0answers
18 views

Evaluating annotations with gold standard

I want to evaluate the following: I have a gold set with documents wherefore the meta data is annotated; this means for an article i have annotated what the author is, what the title is, etc.. I now ...
17
votes
2answers
4k views

Measuring Document Similarity

To cluster (text) documents you need a way of measuring similarity between pairs of documents. Two alternatives are: Compare documents as term vectors using Cosine Similarity - and TF/IDF as the ...
0
votes
0answers
13 views

Calculating parameters for a custom ranking algorithm with no training data

On my site, we want to be able to sort search results for books by hot they are. When a book is added to the site its hotness is set to number of hours since the epoch, purchases, reviews and ...
0
votes
0answers
66 views

Are there differences between Delta TF-IDF and TF-IDF?

Are there differences between both algorithm or not ? i mean if i implement for ex Delta TF-IDF in a project instead of ...
0
votes
1answer
23 views

What are distinctive terms?

Here $n$ is the number of distinctive terms in document $d$. What is the meaning of distinctive? My guess is that it's terms that remain after filtering document from terms that aren't necessary, ...
0
votes
0answers
23 views

Picking a right classification metric

I have a classification problem that I ended up with only true positives (TP). Now, I would like to measure my classification but I wonder what kind of metric I should pick for the evaluation. Let ...
0
votes
0answers
64 views

Is precision in recommender system related to mean average error (MAE)?

A recommender system is being evaluated while increasing the neighborhood size. The highest precision was achieved between 10-15 neighbors(users) while the lowest MAE was in the range from 30-40 ...
0
votes
0answers
14 views

parsing semi-structured textual data poorly matrix formatted

I have found many approaches in the literature that could deal with my problem (which is parsing poorly formatted textual data having a matrix structure but whose content may vary, headers being ...
2
votes
0answers
93 views

Search in a graph of medical records

I have a hierarchical order of a disease list. Just for example: Respiratory system disease 1.1. Asphyxia neonatorum 1.2. Croup 1.3. Lower respiratory tract disease 1.4. Bronchial disease ...
0
votes
0answers
10 views

Modeling 2-D data as vector

As part of my class project i had to use decision tree classification on a training set which contains a set of matrices where each row is a vector recorded at a particular time stamp and each row ...
0
votes
0answers
12 views

Context-aware information retrieval?

I was asked a puzzle lately and so I decided to cheat and find the answer on Google. The puzzle was asked to me in a different language than English, so I had to think about the main context and then ...
1
vote
0answers
142 views

Difference between Weighted Average Entropy and Adjusted Mutual Information (for evaluating Clustering)

I was advised by my team leader to use this weighted average entropy to evaluating the performance of my dbscan clustering algorithm, and its mathematical formulation is: Scikit provides what many ...
0
votes
1answer
43 views

Measure precision

This is used in information retrieval. I have an algorithm that uses a sample set to predict a yes / no. I think the correct term is binomial. Yes this document is about sports or no this document ...
0
votes
0answers
48 views

choosing best value for N when using N-Gram approach

the question is quite general, but I am doing a research related to supervised machine learning to classify two set of characters into two categories. in fact, I want to compute some measures of ...
0
votes
2answers
110 views

Correct Evaluation of Random Forest on fixed training/test set

I have to test the performance of Random Forest on the same dataset (text classification) with about 118.000 instances of which about 1/3 is used for training and 2/3 is used for testing. The division ...
2
votes
2answers
88 views

Weighting words based on position in text

I'm currently working on semantic analysis and had a question about text organization and structure. Are there any algorithms, or statistical / machine-learning models that weight the importance of a ...
5
votes
1answer
112 views

In inverse theory, how do I transform the averaging kernel matrix to a new grid?

Rodgers and Connor (2003) describe how measurements by remote sounders can be properly compared, taking into account differences in averaging kernels and error covariances. They make the assumption ...
2
votes
1answer
2k views

“Mean average precision” (MAP) evaluation statistic - understanding good/bad/chance values

I'm evaluating a multilabel classifier. I'm familiar with the Area Under the Curve statistic, which has some nice properties (e.g. chance level is always 50%). But for some applications, it's more ...
1
vote
0answers
15 views

Information retrieval performance measures for unknown test collection?

I am evaluating a web search relevance feedback algorithm. The algorithm uses Bing API as source for its result sets. To evaluate the algorithm I will be conducting a user study. In the end I will ...
0
votes
0answers
20 views

Evaluation of IR approach without test collections

I am trying to evaluate an information retrieval approach. More specifically, it's a query expansion algorithm, based on topic distribution in retrieved documents. I want to evaluate my approach ...
1
vote
1answer
42 views

How do I perform an IDF calculation?

How do I perform an IDF calculation? I am uncertain as to whether IDF should be calculated in per-class level or for the entire document set (that contains multiple classes).
0
votes
0answers
33 views

What are the mathematics I need to learn, before I start research in data mining [duplicate]

I usually use text mining, graph mining, Information retrieval, and natural lanuage processing. Also i will use the fundamental concepts of data mining like classification, association and clustering. ...
1
vote
1answer
1k views

Create a matrix of tf-idf values from documents

I have a set of documents like: D1 = "The sky is blue." D2 = "The sun is bright." D3 = "The sun in the sky is bright." and a ...
1
vote
0answers
141 views

Learning to Rank: query-dependent vs. query-independent features

I've been doing some reading about learning to rank - specifically lambdaMART - and one thing I am confused about is the role of features. When training a model, should one only use query-dependent ...
0
votes
1answer
45 views

Choosing the best set of keywords

I have a dataset of tweets collected using twitter streaming API on a particular topic (say 'football') using around 40 keywords. Now if I'm going to track the same topic (football) in future how do I ...
4
votes
3answers
504 views

Summary statistics of the precision-recall curve

From what I understand, one can use the AUC of the ROC curve as a summary statistic of the full curve. Q1. Are there any similar summary statistics that one can use on a single precision-recall ...
2
votes
1answer
359 views

What is the difference between accuracy and agreement?

According to Manning et al. (p. 155) accuracy is the sum of the diagonal in the confusion matrix divided by the sum of all items. On the other hand, following Artstein and Poesio (p . 558) precisely ...
0
votes
1answer
98 views

Automatic labeling of training set

I have once meet the following question, given a training set, is that possible to do the automatic labelling? In addition, if this training set consists of plain text files, is that possible to know ...
1
vote
1answer
33 views

“Exotic” text representations methods?

I'm looking to the different methods of representing a text into a machine-readable format. However, until now, I only found "Bag of Words" approachs with a lot of variations (boolean BoW, weighted ...
3
votes
2answers
247 views

Dataset and papers for baseline [closed]

I'm doing a project about Topic Detection and Tracking in text. I need to perform a baseline so I can compare existing results with mine. I read some papers where they use datasets that are not so ...
0
votes
0answers
51 views

Calculation of normalization constant

This is an equation from the paper "A Content-based Probabilistic Correction Model for OCR Document Retrieval" - Rong Jin, Alex G. Hauptmann , ChengXiang Zhai $$P(w|M_{\text{orig}})= ...
1
vote
2answers
280 views

Most important journals in data mining/ML, NLP and IR?

Can you please provide with me with the names of the most important journals in data mining, machine learning, natural language processing and information retrieval?