I've been thinking about an algorithm that should rougly be able to guess the value of an english .com domain in most cases.
For this to work I want to perform tests that consider the strengths and weaknesses of an english .com domain.
A simple point based system is what I had in mind, where each domain property can be given a certain weight to factor it's importance in.
I had these properties in mind:
domain character length
Eg. initially 20 points are added. If the domain has 4 or less characters, no points are substracted. For each extra character, one or more points are substracted on an exponential basis (the more characters, the higher the penalty).
domain characters
Eg. initially 20 points are added. If the domain is only alphabetic, no points are substracted. For each non-alhabetic character, X points are substracted (exponential increase again).
domain name words
Scans through a big offline english database, including non-formal speech, eg. words like "tweet" should be recognized.
Question 1 : where can I get a modern list of english words for use in such application? Are these lists available for free? Are there lists like these with non-formal words?
The more words are found per character, the more points are added. So, a domain with a lot of characters will still not get a lot of points.
words hype-level
I believe this is a tricky one, but this should be the cause to differentiate perfect but boring domains from perfect and interesting domains.
For example, the following domain is probably not that valueable: www.peanutgalaxy.com
The algorithm should identify that peanuts and galaxies are not very popular topics on the web. This is just an example.
On the other side, a domain like www.shopdeals.com should ring a bell to the hype test, as shops and deals are quite popular on the web.
My initial thought would be to see how often these keywords are references to on the web, preferably with some database.
Question 2: is this logic flawed, or does this hype level test have merit?
Question 3: are such "hype databases" available? Or is there anything else that could work offline? The problem with eg. a query to google is that it requires a lot of requests due to the many domains to be tested.
domain name spelling mistakes
Domains like "freemoneyz.com" etc. are generally (notice I am making a lot of assumptions in this post but that's necessary I believe) not valueable due to the spelling mistakes.
Question 4: are there any offline APIs available to check for spelling mistakes, preferably in javascript or some database that I can use interact with myself. Or should a word list help here as well?
use of consonants, vowels etc.
A domain that is easy to pronounce (eg. Google) is usually much more valueable than one that is not (eg. Gkyld).
Question 5: how does one test for such pronuncability? Do you check for consonants, vowels, etc.? What does a valueable domain have? Has there been any work in this field, where should I look?
That is what I came up with, which leads me to my final two questions.
Question 6: can you think of any more english .com domain strengths or weaknesses? Which? How would you implement these?
Question 7: do you believe this idea has any merit or all, or am I too naive? Anything I should know, read or hear about? Suggestions/comments?
Thanks!
The value of a domain is the highest price someone is prepared to pay on the day of sale - it really is pretty arbitrary, especially when un pre-registered domain can be bought for less than $20.
The domain evaluator tool is what you're looking for.
Here's a screenshot.
Optionally, you can make a simple bidding website. I someone clicks that there is interest in a certain domain, then it raises the hidden price. Only when a user does XYZ can they see the price, by then the community has successfully done your valuation automatically.
Related
I don't really know where to start with this project, and so I'm hoping a broad question can at least point me in the right direction.
I have 2 data sets right now, each about 5gb with 2million observations. They are the assessed and historical data gathered for property listings of a given area for a certain amount of time. What I need to do is match properties to one another. So a property may arise in the historical since it gets sold 2 or 3 times during the period. In this historical I have the seller info, the loan info, and sale info. In the assessor data I have all of the characteristics that would describe the property sold. So in order to do any pricing model, I need to match the two.
I have variables that are similar in each, however they are going to differ slightly (misspellings, abbreviations, etc). Does anyone have any recommendations for me about going through this? First off, what program would I want to do this in? I have experience in STATA, R and a little bit of SAS and Matlab, but I'd prefer to use the former two.
I read through this:
Data matching algorithm
Where he uses .NET and one user suggested a Levenshtein approach (where the distance between strings is calculated) so for fields like Address I could use this and weight the approximate accuracy between the two string. Then it was suggested maybe to use Soundex for maybe Name of the seller/owner.
But I'm really lost in how to implement any of this, and before I approach anyone in my department I really need to have some sort of idea of what I'm doing!
Any help or advice would be immensely helpful.
Yes, there are several good algorithms for the string matching problem you describe, namely:
jaro-winkler,
smith-waterman,
dice-sorense
soundex
damerau-levenshtein, and
monge-elkan
to name the few.
I recommend A Comparison of String Distance Metrics for Name-Matching Tasks, by W. W. Cohen, P. Ravikumar, S. Fienberg for an overview of what might be working the best for what.
SoftTFIDF claims to be the best one. It is available as a Java package. There are other implementations of string matching and record linkage algorithms available in:
Java (SecondString),
Python (JellyFish),
C# (FuzzyString), and
Scala StringMetric
libraries.
I'm looking for a possibly simple solution of the following problem:
Given input of a sentence like
"Absence makes the heart grow fonder."
Produce a list of basic words followed by their difficulty/complexity
[["absence", 0.5], ["make", 0.05], ["the", 0.01"], ["grow", 0.1"], ["fond", 0.5]]
Let's assume that:
all the words in the sentence are valid English words
popularity is an acceptable measure of difficulty/complexity
base word can be understood in any constructive way (see below)
difficulty/complexity is on scale from 0 - piece of cake to 1 - mind-boggling
difficulty bias is ok, better to be mistaken saying easy is though than the other way
working simple solution is preferred to flawless but complicated stuff
[edit] there is no interaction with user
[edit] we can handle any proper English input
[edit] a word is not more difficult than it's basic form (because as smart beings we can create unhappily if we know happy), unless it creates a new word (unlikely is not same difficulty as like)
General ideas:
I considered using Google searches or sites like Wordcount to estimate words popularity that could indicate its difficulty. However, both solutions give different results depending on the form of entered words. Google gives 316m results for fond but 11m for fonder, whereas Wordcount gives them ranks of 6k and 54k.
Transforming words to their basic forms is not a must but solves ambiguity problem (and makes it easy to create dictionary links), however it's not a simple task and its sense could me found arguable. Obviously fond should be taken instead of fonder, however investigating believe instead of unbelievable seems to be an overkill ([edit] it might be not the best example, but there is a moment when modifying basic word we create a new one like -> likely) and words like doorkeeper shouldn't be cut into two.
Some ideas of what should be consider basic word can be found here on Wikipedia but maybe a simpler way of determining it would be a use of a dictionary. For instance according to dictionary.reference.com unbelievable is a basic word whereas fonder comes from fond but then grow is not the same as growing
Idea of a solution:
It seems to me that the best way to handle the problem would be using a dictionary to find basic words, apply some of the Wikipedia rules and then use Wordcount (maybe combined with number of Google searches) to estimate difficulty.
Still, there might (probably is a simpler and better) way or ready to use algorithms. I would appreciate any solution that deals with this problem and is easy to put in practice. Maybe I'm just trying to reinvent the wheel (or maybe you know my approach would work just fine and I'm wasting my time deliberating instead of coding what I have). I would, however, prefer to avoid implementing frequency analysis algorithms or preparing a corpus of texts.
Some terminology:
The core part of the word is called a stem or a root. More on this distinction later. You can think of the root/stem as the part that carries the main meaning of the word and will appear in the dictionary.
(In English) most words are composed of one root (exception: compounds like "windshield") / one stem and zero or more affixes: the affixes that come after the root/stem are called suffixes, and the affixes that precede the root/stem are called prefixes. Examples: "driver" = "drive" (root/stem) + suffix "-er"; "unkind" = "kind" (root/stem) + "un-" (prefix).
Suffixes/prefixes (=affixes) can be inflectional or derivational. For example, in English, third-person singular verbs have an s on the end: "I drive" but "He drive-s". These kind of agreement suffixes don't change the category of the word: "drive" is a verb regardless of the inflectional "s". On the other hand, a suffix like "-er" is derivational: it takes a verb (e.g. "drive") and turns it into a noun (e.g. "driver")
The stem, is the piece of the word without any inflectional affixes, whereas the root is the piece of the word without any derivational affixes. For instance, the plural noun "drivers" is decomposable into "drive" (root) + "er" (derivational affix, makes a new stem "driver") + "s" (plural).
The process of deriving the "base" form of the word is called "stemming".
So, armed with this terminology it seems that for your task the most useful thing to do would be to stem each form you come across, i.e. remove all the inflectional affixes, and keep the derivational ones, since derivational affixes can change how common the word is considered to be. Think about it this way: if I tell you a new word in English, you will always know how to make it plural, 3rd-person singular, however, you may not know some of the other words you can derive from this). English being inflection-poor language, there aren't a lot of inflectional suffixes to worry about (and Google search is pretty good about stripping them off, so maybe you can use the Google's stemming engine just by running your word forms through google search and getting out the highlighted results):
Third singular verbal -s: "I drive"/"He drive-s"
Nominal plural `-s': "One wug"/"Two wug-s". Note that there are some irregular forms here such as "children", "oxen", "geese", etc. I think I wouldn't worry about these.
Verbal past tense forms and participial forms. The regular ones are easy: the past tense has -ed for past tense and past participle ("I walk"/"I walk-ed"/"I had walk-ed"), but there are quite a few of irregular ones (fall/fell/fallen, dive/dove/dived?, etc). Maybe make a list of these?
Verbal -ing forms: "walk"/"walk-ing"
Adjectival comparative -er and superlative -est. There are a few irregular/suppletive ones ("good"/"better"/"best"), but these should not present a huge problem.
These are the main inflectional affixes in English: I may be forgetting a few that you could discover by picking up an introductory Linguistics books. Also there are going to be borderline cases, such as "un-" which is so promiscuous that we might consider it inflectional. For more information on these types, see Level 1 vs. Level 2 affixation, but I would treat these cases as derivational for your purposes and not stem them.
As far as "grading" how common various stems are, besides google you could various freely-available text corpora. The wikipedia article linked to has a few links to free corpora, and you can find a bunch more by googling. From these corpora you can build a frequency count of each stem, and use that to judge how common the form is.
I'm afraid there is no simple solution to the task of finding "basic" forms. I'm basing that on my memory of my Machine Learning textbook, of which language analysis was part of. You need some database, from which you can get them.
At the same time, please take note that the amount of words people use in everyday language is not that big. You can always ask a user what is the base form of a world you have not seen before. (unless this is your homework, which will be automatically checked)
Eventually, if you don't care about covering all words, you can create simple database, which would contain different forms of the most common words, and then try to use grammatical rules for the less common ones (which would be a good approximation, as actually, the most common words in English are irregular, whereas the uncommon ones are regular, because their original forms have been forgotten).
Note however, i'm no specialist, i'm simply trying to help :-)
I am tasked with trying to create an automated system that removes personal information from text documents.
Emails, phone numbers are relatively easy to remove. Names are not. The problem is hard because there are names in the documents that need to be kept (eg, references, celebrities, characters etc). The author name needs to be removed from the content (there may also be more than one author).
I have currently thought of the following:
Quite often personal names are located at the beginning of a document
Look at how frequently the name is used in the document (personal names tend to be written just once)
Search for words around the name to find patterns (mentions of university and so on...)
Any ideas? Anyone solved this problem already??
With current technology, doing what what you are describing in a fully automated way with a low error rate is impossible.
It might be possible to come up with an approximate solution, but it would still make a lot of errors...... either false positives or false negatives or some combination of the two.
If you are still really determined to try, I think your best approach would be Bayseian filtering (as used in spam filtering). The reason for this is that it is quite good at assigning probabilities based on relative positions and frequencies of words, and could also learn which names are more likely / less likely to be celebrities etc.
The area of machine learning that you would need to learn about to make an attempt at this would be natural language processing. There are a few different approaches that could be used, bayesian networks (something better then a naive bayes classifier), support vector machines, or neural nets would be areas to research. Whatever system you end up building would probably need to use an annotated corpus (labeled set of data) to learn where names should be. Even with a large corpus, whatever you build will not be 100% accurate, so you would probably be better off setting flags at the names for deletion instead of just deleting all of the words that might be names.
This is a common problem in basic cryptography courses (my first programming job).
If you generated a word histogram of your entire document corpus (each bin is a word on the x-axis whose height is frequency represented by height on the y-axis), words like "this", "the", "and" and so forth would be easy to identify because of their large y-values (frequency). Surnames should at the far right of your histogram--very infrequent; given names towards the left, but not by much.
Does this technique definitively identify the names in each document? No, but it could be used to substantially constrain your search, by eliminating all words whose frequency is larger than X. Likewise, there should be other attributes that constrain your search, such as author names only appear once on the documents they authored and not on any other documents.
I have 3 main questions about the algorithms in intelligent web (web 2.0)
Here the book I'm reading http://www.amazon.com/Algorithms-Intelligent-Web-Haralambos-Marmanis/dp/1933988665 and I want to learn the algorithms in deeper
1. People You may follow (Twitter)
How can one determine the nearest result to my requests ? Data mining? which algorithms?
2. How you’re connected feature (Linkedin)
Simply algorithm works like that. It draws the path between two nodes let say between Me and the other person is C. Me -> A, B -> A connections -> C . It is not any brute force algorithms or any other like graph algorithms :)
3. Similar to you (Twitter, Facebook)
This algorithms is similar to 1. Does it simply work the max(count) friend in common (facebook) or the max(count) follower in Twitter? or any other algorithms they implement? I think the second part is true because running the loop
dict{count, person}
for person in contacts:
dict.add(count(common(person)))
return dict(max)
is a silly act in every refreshing page.
4. Did you mean (Google)
I know that they may implement it with phonetic algorithm http://en.wikipedia.org/wiki/Phonetic_algorithm simply soundex http://en.wikipedia.org/wiki/Soundex and here is the Google VP of Engineering and CIO Douglas Merrill speak http://www.youtube.com/watch?v=syKY8CrHkck#t=22m03s
What about first 3 questions? Any ideas are welcome !
Thanks
People who you may follow
You can use the factors based calculations:
factorA = getFactorA(); // say double(0.3)
factorB = getFactorB(); // say double(0.6)
factorC = getFactorC(); // say double(0.8)
result = (factorA+factorB+factorC) / 3 // double(0.5666666666666667)
// if result is more than 0.5, you show this person
So say in the case of Twitter, "People who you may follow" can based on the following factors (User A is the user viewing this "People who you may follow" feature, there may be more or less factors):
Relativity between frequent keywords found in User A's and User B's tweets
Relativity between the profile description of both users
Relativity between the location of User A and B
Are people User A is following follows User B?
So where do they compare "People who you may follow" from? The list probably came from a combination of people with high amount of followers (they are probably celebrities, alpha geeks, famous products/services, etc.) and [people whom User A is following] is following.
Basically there's a certain level of data mining to be done here, reading the tweets and bios, calculations. This can be done on a daily or weekly cron job when the server load is least for the day (or maybe done 24/7 on a separate server).
How are you connected
This is probably a smart work here to make you feel that loads of brute force has been done to determine the path. However after some surface research, I find that this is simple:
Say you are User A; User B is your connection; and User C is a connection of User B.
In order for you to visit User C, you need to visit User B's profile first. By visiting User B's profile, the website already save the info indiciating that User A is at User B's profile. So when you visit User C from User B, the website immediately tells you that 'User A -> User B -> User C', ignoring all other possible paths.
This is the max level as at User C, User Acannot go on to look at his connections until User C is User A's connection.
Source: observing LinkedIN
Similar to you
It's the exact same thing as #1 (People you may follow), except that the algorithm reads in a different list of people. The list of people that the algorithm reads in is the people whom you follow.
Did you mean
Well you got it right there, except that Google probably used more than just soundex. There's language translation, word replacement, and many other algorithms used for the case of Google. I can't comment much on this because it will probably get very complex and I am not an expert to handle languages.
If we research a little more into Google's infrastructure, we can find that Google has servers dedicated to Spelling and Translation services. You can get more information on Google platform at http://en.wikipedia.org/wiki/Google_platform.
Conclusion
The key to highly intensified algorithms is caching. Once you cache the result, you don't have to load it every page. Google does it, Stack Overflow does it (on most of the pages with list of questions) and Twitter not surprisingly too!
Basically, algorithms are defined by developers. You may use others' algorithms, but ultimately, you can also create your own.
People you may follow
Could be one of many types of recommendation algorithms, maybe collaborative filtering?
How you are connected
This is just a shortest path algorithm on the social graph. Assuming there is no weight to the connections, it will simply use breadth-first.
Similar to you
Simply a re-arrangement of the data set using the same algorithm as People you may follow.
Check out the book Programming Collective Intelligence for a good introduction to the type of algorithms that are used for People you may follow and Similar to you, it has great python code available too.
People You may follow
From Twitter blog - "suggestions are based on several factors, including people you follow and the people they follow" http://blog.twitter.com/2010/07/discovering-who-to-follow.html
So if you follow A and B and they both follow C, then Twitter will suggest C to you...
How you’re connected feature
I think you have answered this one.
Similar to you
As above and as you say, although the results are probably cached - so its only done once per session or maybe even less frequently...
Hope that helps,
Chris
I don't use twitter; but with that in mind:
1). On the surface, this isn't that difficult: For each person I follow, see who they follow. Then for each of the people they follow, see who they follow, etc. The deeper you go, of course, the more number crunching it takes.
You can take this a bit further, if you can also efficiently extract the reverse: For those I follow, who also follows them?
For both ways, what's unsaid is a way to weight the tweeters to see if they're someone I'd really want to follow: A liberal follower may also follow a conservative tweeter, but that doesn't mean I'd want follow the conservative (see #3).
2). Not sure, thinking about it...
3). Assuming the bio and tweets are the only thing to go on, the hard parts are:
Deciding what attributes should exist (political affiliation, topic types, etc.)
Cleaning each 140 characters to data-mine.
Once you have the right set of attributes, then two different algorithms come to mind:
K means clustering, to decide which attributes I tend to discriminate on.
N-Nearest neighbor, to find the N most similar tweeters to you given the attributes I tend to give weight to.
EDIT: Actually, a decision tree is probably a FAR better way to do all of this...
This is all speculative, but it sounds fun if one were getting paid to do this.
I have a list of X sites that I need to classify in some way. Is the site about cars, health, products or is it about everything(wikihow, about.com, etc?) What are some of the better ways to classify sites like this? Should I get keywords that bring traffic to the site and use those? Should I read the content of some random pages and judge it off of that?
Well if the site is well designed there will be meta tags in the header specifically for this.
Yahoo has a api to extract terms, http://developer.yahoo.com/search/content/V2/termExtraction.html
"The Term Extraction Web Service provides a list of significant words or phrases extracted from a larger content. It is one of the technologies used in Y!Q."
Maybe I'm a bit biased (disclaimer : I have a degree in library science, and this topic is one of the reasons I got the degree), so the easiest answer is that there is no best way.
Consider this like you would database design -- once you have your system populated, what sort of questions are you going to ask of it?
Is the fact that the site is run by the government significant? Or that it uses flash? Or that the pages are blue? Or that it's a hobbyist site? Or that the intended audience is children?.
Then we get the question of if we're going to have a hierarchical category for any of the facets we're concerned with -- if it's about both cars and motorcycles, should we use the term 'vehicles' instead? And if we do that, will we use keyword expansion so that 'motorcycle' matches the broader terms (ie, vehicles) as well?
So ... the point is ... figure out what your needs are, and work towards that. 'Best' will never come, even with years of refinement (if anything, it gets more difficult, as terms start changing meanings. Remember when 'weblog' was related to web server metrics?)
This is a tough question to answer. Consider:
How granular do you want your classification to be?
Do you want to classify sites based on your own criteria or the criteria provided by the sites? In other words, if a site classifies itself as "a premier source for motorcycle maintenance", do you want to create a "motorcycle maintenance" category just for that site? This, of course, will cause your list to become inconsistent. However, if you pigeon-hole the sites to follow your own classification scheme, there is a loss of information, and a risk that the site will not match any of the categories you've defined.
Do you allow subcategories? The problem becomes much more complicated if so.
Can a site belong to more than one category? If so, is there an ordering or a weight (ie. Primary Category, Secondary Categories, etc.), or do you follow a scheme similar to SO's tags?
As an initial stab at the problem, I think I'd define a set of categories, and then spider each site, keeping track of the number of occurrences of each category name, or a mutation thereof. Then, you can choose the name that had the greatest number of "hits."
For instance, given the following categories:
{ "Cars", "Motorcycles", "Video Games" }
Spidering the following blocks of text from a site:
The title is an incongruous play on the title of the book Zen in the Art of Archery by Eugen Herrigel. In its introduction, Pirsig explains that, despite its title, "it should in no way be associated with that great body of factual information relating to orthodox Zen Buddhist practice. It's not very factual on motorcycles, either."
and:
Most motorcycles made since 1980 are pretty reliable if properly maintained but that's a big if. To some extent the high reliability of today's motorcycles has worked to the disadvantage of many riders. Some riders have been lulled into believing that motorcycles are like modern cars and require essentially no maintenance. This is not the case (even with cars). Modern bikes require less maintenance than they did in the 60's and 70's but they still need a lot more maintence than a car. This higher reliability also means that there are a a whole bunch of motorcyclists out there who haven't a clue how to work on their bikes or what really needs to be done to ensure reliability.
We get the following scores:
{ "Cars" : 3, "Motorcycles" : 4, "Video Games" : 0 }
And we can thus categorize the site as being related mostly to "Motorcycles".
Note that I said "mutations thereof" with regards to category names, so "motorcycle" or "car" are both detected. We can see from this that you should also perhaps consider using a list of related words. For instance, perhaps we should detect the word "motorcyclists" when searching for instances of "Motorcycles". Perhaps we should've seen "modern bikes", too.
You could also save those hits, perhaps combined them with some other data, and use Bayesian probability to determine which category the site is most likely to fit into.