I want to find out a few things about OpenStreetMapX which from what I understand works well with transportation-based networks. I am wondering if it's also possible to use this package along with lightgraphs.jl to create a power grid network. In my case, I have filtered some power grid data using osmosis (a piece of software that allows filtering OpenStreetMap data based on a tag)
I want to know whether it is relevant to use OpenStreetMapX for this kind of data (power grid)?
using OpenStreetMapX
# Load power data for Germany
deData = get_map_data("D:/PowerGridNetwork/data/germany/de_power_160718.osm")
# Get roadways (which I believe has the meta data for edges)
deData.roadways
I ended up with metadata for power as well as roads, which I am wondering, how it came in the first place. Since I filtered only the power data.
The next question I have is, does deData.e returns an adjacency list?. Since what I am really after is creating a MetaGraph with nodes and edges with their respective properties.
Any ideas?
Thanks in advance
I have around 1140 terms in three documents (after removing sparse terms). I want to have the information about the clusters. I have produced clusters as shown in attached image but I am unable to read them. I have also tried k-mean clusters but the same problem persists. I am not so much interested in all the terms but clearly defined few three or four clusters would do the job. I have been using tm package in R for text mining.
Secondly I am also looking for finding association in terms with in a single document; for this how can I split a text file into several text files i.e. if my file has three sentences:
Doc: "My name is ABC. I live in XYZ. I am cousin of TUV."
I would like to split it as:
Doc_1: My name is ABC.
Doc_2:I live in XYZ.
Doc_3: I am cousin of TUV.
So that I have three rows and columns of terms in dtm instead of a single row and column of terms.
and
You ask more than one question. I will address your first one. It seems unrealistic to expect to put 1140 strings in your graph and expect to see anything. You need a way to be able to see a bit of it at a time. You can cut the tree and look a smaller pieces in the lower part of the tree to control how much you are seeing at one time.
Here is an example. Even with 150 points, it is hard to see what is going on.
D = as.dendrogram(hclust(dist(iris[,1:4])))
plot(D)
But if you cut the tree, you can look at individual lower branches and understand that part.
Cuts = cut(D, 4)
plot(Cuts$lower[[2]])
Of course, you will need to experiment around a bit to find good places to cut your tree.
I am analysing a coauthorship network (net) of V(net)=1327 and E(net)=4121.
I have tried to find the
assortativity.nominal(net, types=V(net)$field)
this is based on the field where the researcher belongs. I do not know why, but R crush each time I want to run this. I have run
assortativity(net, types=V(net)$publication)
that is in function of the number of publications or coautorships each researcher has, in this case there is no problem.
I just fear that the case with assortativity.nominal has to do with the size and order of the network.
Something that might work:
assortativity_nominal(graph,as.numeric(as.factor(V(graph)$attribute)))
The problem is with the trait being NA for some of the vertices. If you change all the NAs to "none", then it works, however, you probably don't want this and nor do I, and I don't know how to get round it.
Hello again stackoverflow-ers ! hope you are well
I am working on a project and am essentially trying to create a decision tree. The data is a for a bank's campaign concerning how well the campaign incentivized the customers to open up a term deposit.
Anyhow, i've worked through coding etc with some assistance from online resources and hit the wall on one part.
One of the columns is the term deposit amout figure for all customers and as I plotted the data to visualize it (please see attached the plot)
Since the data is so dispersed i wanted to discretize it. I used the following code:
BankTraining$TDepositAMTD<-cut(BankTraining$TermDepositAMT, right=F,
breaks= c(0,5000,10000,15000,20000,max(BankTraining$TermDepositAMT)))
here
The Y axis is the number of observations and X axis is the dollar amount of term deposits.
However, viewing the column after this step i see :
table(BankTraining$TDepositAMTD)
[0,5e+03) [5e+03,1e+04)
5213 8631
[1e+04,1.5e+04) [1.5e+04,2e+04)
8367 1698
[2e+04,3e+04)
3121
Now, clearly this is no good. Once the decision tree is created it shows these weird categories which I cannot interpret.
Could someone shed light on this issue please? Much gratitude for your help.
Since it seems you are not happy with the cuts you are producing, have a go at it with:
library(Hmisc)
Groups <- cut2(data, g = 5) # g is the number of groups or levels I want
The package Hmisc can be found here.
As for your weird categories, we would need to see what packages/ algorithms along with how you call it as these categories may be a product of your binning and some consequence of default behavior. Happy to edit when more information is available.
I need to automatically match product names (cameras, laptops, tv-s etc) that come from different sources to a canonical name in the database.
For example "Canon PowerShot a20IS", "NEW powershot A20 IS from Canon" and "Digital Camera Canon PS A20IS"
should all match "Canon PowerShot A20 IS". I've worked with levenshtein distance with some added heuristics (removing obvious common words, assigning higher cost to number changes etc), which works to some extent, but not well enough unfortunately.
The main problem is that even single-letter changes in relevant keywords can make a huge difference, but it's not easy to detect which are the relevant keywords. Consider for example three product names:
Lenovo T400
Lenovo R400
New Lenovo T-400, Core 2 Duo
The first two are ridiculously similar strings by any standard (ok, soundex might help to disinguish the T and R in this case, but the names might as well be 400T and 400R), the first and the third are quite far from each other as strings, but are the same product.
Obviously, the matching algorithm cannot be a 100% precise, my goal is to automatically match around 80% of the names with a high confidence.
Any ideas or references is much appreciated
I think this will boil down to distinguishing key words such as Lenovo from chaff such as New.
I would run some analysis over the database of names to identify key words. You could use code similar to that used to generate a word cloud.
Then I would hand-edit the list to remove anything obviously chaff, like maybe New is actually common but not key.
Then you will have a list of key words that can be used to help identify similarities. You would associate the "raw" name with its keywords, and use those keywords when comparing two or more raw names for similarities (literally, percentage of shared keywords).
Not a perfect solution by any stretch, but I don't think you are expecting one?
The key understanding here is that you do have a proper distance metric. That is in fact not your problem at all. Your problem is in classification.
Let me give you an example. Say you have 20 entries for the Foo X1 and 20 for the Foo Y1. You can safely assume they are two groups. On the other hand, if you have 39 entries for the Bar X1 and 1 for the Bar Y1, you should treat them as a single group.
Now, the distance X1 <-> Y1 is the same in both examples, so why is there a difference in the classification? That is because Bar Y1 is an outlier, whereas Foo Y1 isn't.
The funny part is that you do not actually need to do a whole lot of work to determine these groups up front. You simply do an recursive classification. You start out with node per group, and then add the a supernode for the two closest nodes. In the supernode, store the best assumption, the size of its subtree and the variation in it. As many of your strings will be identical, you'll soon get large subtrees with identical entries. Recursion ends with the supernode containing at the root of the tree.
Now map the canonical names against this tree. You'll quickly see that each will match an entire subtree. Now, use the distances between these trees to pick the distance cutoff for that entry. If you have both Foo X1 and Foo Y1 products in the database, the cut-off distance will need to be lower to reflect that.
edg's answer is in the right direction, I think - you need to distinguish key words from fluff.
Context matters. To take your example, Core 2 Duo is fluff when looking at two instances of a T400, but not when looking at a a CPU OEM package.
If you can mark in your database which parts of the canonical form of a product name are more important and must appear in one form or another to identify a product, you should do that. Maybe through the use of some sort of semantic markup? Can you afford to have a human mark up the database?
You can try to define equivalency classes for things like "T-400", "T400", "T 400" etc. Maybe a set of rules that say "numbers bind more strongly than letters attached to those numbers."
Breaking down into cases based on manufacturer, model number, etc. might be a good approach. I would recommend that you look at techniques for term spotting to try and accomplish that: http://www.worldcat.org/isbn/9780262100854
Designing everything in a flexible framework that's mostly rule driven, where the rules can be modified based on your needs and emerging bad patterns (read: things that break your algorithm) would be a good idea, as well. This way you'd be able to improve the system's performance based on real world data.
You might be able to make use of a trigram search for this. I must admit I've never seen the algorithm to implement an index, but have seen it working in pharmaceutical applications, where it copes very well indeed with badly misspelt drug names. You might be able to apply the same kind of logic to this problem.
This is a problem of record linkage. The dedupe python library provides a complete implementation, but even if you don't use python, the documentation has a good overview of how to approach this problem.
Briefly, within the standard paradigm, this task is broken into three stages
Compare the fields, in this case just the name. You can use one or more comparator for this, for example an edit distance like the Levenshtein distance or something like the cosine distance that compares the number of common words.
Turn an array fo distance scores into a probability that a pair of records are truly about the same thing
Cluster those pairwise probability scores into groups of records that likely all refer to the same thing.
You might want to create logic that ignores the letter/number combination of model numbers (since they're nigh always extremely similar).
Not having any experience with this type of problem, but I think a very naive implementation would be to tokenize the search term, and search for matches that happen to contain any of the tokens.
"Canon PowerShot A20 IS", for example, tokenizes into:
Canon
Powershot
A20
IS
which would match each of the other items you want to show up in the results. Of course, this strategy will likely produce a whole lot of false matches as well.
Another strategy would be to store "keywords" with each item, such as "camera", "canon", "digital camera", and searching based on items that have matching keywords. In addition, if you stored other attributes such as Maker, Brand, etc., you could search on each of these.
Spell checking algorithms come to mind.
Although I could not find a good sample implementation, I believe you can modify a basic spell checking algorithm to comes up with satisfactory results. i.e. working with words as a unit instead of a character.
The bits and pieces left in my memory:
Strip out all common words (a, an, the, new). What is "common" depends on context.
Take the first letter of each word and its length and make that an word key.
When a suspect word comes up, looks for words with the same or similar word key.
It might not solve your problems directly... but you say you were looking for ideas, right?
:-)
That is exactly the problem I'm working on in my spare time. What I came up with is:
based on keywords narrow down the scope of search:
in this case you could have some hierarchy:
type --> company --> model
so that you'd match
"Digital Camera" for a type
"Canon" for company and there you'd be left with much narrower scope to search.
You could work this down even further by introducing product lines etc.
But the main point is, this probably has to be done iteratively.
We can use the Datadecision service for matching products.
It will allow you to automatically match your product data using statistical algorithms. This operation is done after defining a threshold score of confidence.
All data that cannot be automatically matched will have to be manually reviewed through a dedicated user interface.
The online service uses lookup tables to store synonyms as well as your manual matching history. This allows you to improve the data matching automation next time you import new data.
I worked on the exact same thing in the past. What I have done is using an NLP method; TF-IDF Vectorizer to assign weights to each word. For example in your case:
Canon PowerShot a20IS
Canon --> weight = 0.05 (not a very distinguishing word)
PowerShot --> weight = 0.37 (can be distinguishing)
a20IS --> weight = 0.96 (very distinguishing)
This will tell your model which words to care and which words to not. I had quite good matches thanks to TF-IDF.
But note this: a20IS cannot be recognized as a20 IS, you may consider to use some kind of regex to filter such cases.
After that, you can use a numeric calculation like cosine similarity.