Vector Space Model implementation

Hi,
Does anybody know where I can find a java implementation of "vector space model"? Or simply a java program to extract keywords from an HTML page?
Actually I don't know if this is the write forum to pose this question!
Edited by: Marziye on May 28, 2008 10:55 PM

You can take a look at the Apache Lucene project. It should be possible to extract keywords from documents with it. Anyway, it is not that hard to implement the vector space model yourself!

Similar Messages

Implementation of state space model with constant disturbance in mathscript and simulation

I am new to LabVIEW and now I am doing a project realizing heater control in 8 rooms.
I have realized the state space model in the form x(k+1)=x(k)+u(k) using mathscript (using c_to_d) and feed it into control and simulation loop for simulation.
My problem is, in my project, I have to consider the disturbance from the other rooms. So the statespace model changed to be x(k+1)=x(k)+u(k)+E*d, where E is the matrix concerning the disturbance and d is the vector of disturbance. How could I implement the disturbance and discretize the new model in mathscript and which function to choose for the simulation. Discrete state space stochastic model?
Appreciate your kind help.

Hello, state space models in LabVIEW most of the time are being implemented by utilizing mathscript syntax
in addition with some functions of the LabVIEW Control Design and Simulation Module.
There´s a couple of nice tutorials for control design with these tools which I´d like to point you to as a first step.
http://www.ni.com/white-paper/6368/en/
http://www.ni.com/white-paper/6368/en/
http://www.ni.com/white-paper/6435/en/
http://home.hit.no/~hansha/documents/lab/Lab%20Work/MathScript/MathScript%20Lab%20-%20Part%20II.pdf
regards
Marco Brauner AES NIG

I have a state space model of a complex system. can anyone help me for implementing MPC and e-MPC control for the same?????

Hi everyone. I am new to the forums, so let me be as mprecise as possible. i know the basic functionalities of Labview with MPC block etc. However, i dont know how to go ahead with implementing MPC control for a system whose state space model i possess. can anyone help me out?? the problem is that i dont even know the approach or the starting point..

This happens if you remove a program manually, but still have the registry keys to load files from this program.<br />
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*http://technet.microsoft.com/en-us/sysinternals/bb963902.aspx
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Plot a state-space model

Hi!
I'm currently doing a project and I'm stuck and am in need for some help.
I've done a state-space model that I'm using for this project. I've used Matlab (with and without simulink) to simulate this model and to plot its behaviour. But when I want to do this in LabVIEW, i get stuck.
I dont want to use Mathscript 'cause then it would be using Matlab.
Does anybody have some ideas of how I can simulate and plot my state-space model from the matrix parameters that i have?
Look at the attachment, I want to plot x.
Solved!
Go to Solution.
Attachments:
State-Space Model.png ‏11 KB

We have so many different ways to do this. Try to look at the following shipping examples:
C:\Program Files (x86)\National Instruments\LabVIEW 2011\examples\Control and Simulation\Control Design\Model Construction\CDEx Creating SS Model from String Matrix.vi
C:\Program Files (x86)\National Instruments\LabVIEW 2011\examples\Control and Simulation\Control Design\Model Construction\CDEx Rendering State-Space Equations.vi
C:\Program Files (x86)\National Instruments\LabVIEW 2011\examples\Control and Simulation\Control Design\Time Analysis\CDEx Time Domain Analysis.vi
C:\Program Files (x86)\National Instruments\LabVIEW 2011\examples\Control and Simulation\Simulation\Continuous Linear\SimEx state space.vi
They show how you can use the product to create a State-Space (SS) model, show the rendered model on the front panel, do a linear simulation of a model and implement the state-space model in the Control and Simulation Loop, respectively.
Notice also that we have an extensive amount of examples available for you. Hope this helps...
Barp - Control and Simulation Group - LabVIEW R&D - National Instruments

Configuring a third axis on vector space to perform a tangential following

Is there some kind a function call/mode in flexmotion library to configure a third axis in a vector space to perform a tangential following (ie to remain tangent to the trajectory of the other two axis)?

Tulio,
Thanks for the explanation. This makes perfect sense.
The Flexmotion driver does not have any built in function to perform this type of motion, however it would be relatively straightforward to implement this for contour moves. You could set this up as a 3 axis contour move. Based on the list of X,Y coordinates, use a simple difference equation to get the slope of the trajectory at each point. Convert this slope to rotation in counts and use these values for the third axis (cutter angle). This could be implemented with just a couple VIs or lines of code with negligible processing overhead or you could even use just a spreadsheet. I have attached below a spreadsheet that shows an example of using a difference equation (centra
l difference) to get cutter positions based on X,Y trajectory data.
Cheers,
Brent R.
Applications Engineer
National Instruments
Attachments:
Tangent_Following.xls ‏18 KB

How to setup breakpoints in a vector space?

Hi,
How to setup breakpoints in a 2D vector space in NI 7344 and check for them using flex_read_breakpoint_status_rtn?
Thanks.

Hi,
Is Office Communicator something to do with the Word, Exel and Powerpoint Office Package ?
What sort of Screen Names or IDs do you use with that ?
If these are MSN/Live accounts names then it can be made to work for Text Chats but not Video or Audio Only chats
10:38 PM Friday; April 20, 2012
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
 iMac 2.5Ghz 5i 2011 (Lion 10.7.2)
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 Mac OS X (10.6.8),
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Motion and Vector Space Question

I have an x-axis stage and a y-axis stage with 2 different leadscrew pitches, i.e.: one table has a 5 turns per inch leadscrew and the other has a 50 turn per inch leadscrew. Consequently, the stepper motors attached have to operate at different speeds (10x difference) in order for the tables to have the same velocity. I have this accounted for in the axis configuration settings in the NI MAX explorer. When I am configuring automated moves in LabView and set up a "vector space" composed of the two axis, it seems that the motors operate at the same speed and ignore the MAX settings. I thought that after intializing the controller, the current axis settings would be carried over and applied through the vector space and to the actual move
(a 2D move made in Motion Assistant). Am I missing something? Do I need to load the velocity for each axis with a flexmotion VI somewhere in the code? I'd like to command the motrs to move at 2 different speeds so the tables move at the same velocities. Any comments would be appreciated. An abbreviated sample of some of the code is attached. Thanks. ROB
Attachments:
sample.vi ‏39 KB

Rob,
you should be able to adjust the pitch of the leadscrews by setting the stepper steps per revolution and/or the encoder steps per revolution settings in MAX accordingly (in your configuration these settings should differ by the factor of 10 for your two axes)
In your application you then have to use the Load Velocity in RPM.flx and the Load Accel/Decel in RPS/sec.flx in order to get the same resulting velocities on both axes. If you do it like this you still have to account the factor of 10 for your target position calculations.
I couldn't find out if you have proceeded like that in your application as the vi you have attached is missing a crucial subvi.
If you are using a four axes board like the PCI-7344 or the PCI-7334 there is another option:
You
could use a third axis that acts as a master for one of your axes (I would prefer the axis with the 5 inch per leadscrew). Your real axis has to be configured to follow the master axis by a factor of 1/10. In your application you configure a vector space for the master axis and the axis that is not configured as slave. Your physical signal connections need to be done to this axis and the slave axis.
Please examine the LabVIEW gearing examples for more information.
In this case you should enter the same values for stepper steps per revolution and/or the encoder steps per revolution in MAX for both axes as the pitch adjustment is done by the gearing.
The advantage of this method is that now you can set the same velocities, accelerations and even target positions for both axes and you never again have to account the pitch factor.
Best regards,
Jochen Klier
Applications Engineering Group Leader
National Instruments Germany GmbH

Tree Model Implementation

Hi All,
I'm need to create a JATO tree implementation and need some advice. I
want to modify the JATO sample tree implementation so that:
1) The model is cached within the user's session.
2) The model is created on demand. i.e. The data associated with the
branches are only retrieved when the branches are opened.
In the sample application E0115TreeView (view) creates a
SimpleTreeModelImpl (model) each time it is instantiated and
SimpleTreeModelImpl (model) creates dummy data each time it is
instantiated.
1) Is there a standard JATO technique for associating a model with a
view (unlike the sample)? Does this involve the ModelTypeMapImpl class?
My tree data is stored in LDAP, so I can't use a standard JATO database
Model classes.
2) The comment in the SimpleTreeModelImpl class definition indicates
that it is normal practice to store the model in the user's session. Is
there a standard JATO technique for doing this?
3) What would be the best way to extend the sample so that I can create
the model on-demand?
Regards,
Dennis Parrott.
[Non-text portions of this message have been removed]

Thanks Todd,
That makes perfect sense.
Regards,
Dennis parrott.
Todd Fast wrote:
Hi Dennis--
I have now added a SimpleTreeModel interface (which extends TreeModel) andhave added an
mapping in ModelTypeMapImpl static initializer. i.e. To registerSimpleTreeModelImpl with the
ModelManager.This is fine, but you can so without the additional interface if you want.
You don't need to register the model in the ModelTypeMap, and you can
instead just pass the implementation class to ModelManager.
In the tree view constructor instead of creating the SimpleTreeModelImpleach time I use the
ModelManager to retrieve the model, indicating that the model should bestored in the sesssion:
public Treeview(View parent, String name) {
super(parent, name);
RequestContext requestContext = getRequestContext();
ModelManager modelManager = requestContext.getModelManager();
Class clazz = SimpleTreeModel.class;
SimpleTreeModel simpleTreeModel =
(SimpleTreeModel)modelManager.getModel( clazz,clazz.getName(), true, true );
setPrimaryModel( simpleTreeModel );
registerChildren();
}This looks good, EXCEPT for the fact that you shouldn't be able to get the
RequestContext at this point via the class's getRequestContext() method (it
isn't set until after the constructor). However, you can use the static
method RequestManager.getRequestContext() instead.
The final bit I need to implement is the model creation on-demand.Currently the entire model
is constructed on the first access and stored in the session. However,when model is large then
this has a performance impact on constructing it for the first time.Instead I would like to
construct peices of the model as the user accesses them. Any ideas?This is really a function of your model implementation. Nodes that are not
needed in a particular rendering of a TreeModel are never accessed by the
framework in that rendering, so you need to implement your model to lazily
fetch sub-trees of the underlying data structure only as needed. Depending
on the technology you are using, this may or may not be difficult.
I suspect that right now you are fetching the entire tree data structure
when the model is created, and this is the root of the problem. You need to
fetch all nodes that are children of the root on the first request, then
fetch child nodes of the next node the user expands on the next request, ad
infinitum. Otherwise, you will have to settle for a one-time performance
hit per session caused by retrieving the entire tree data structure at once.
If you are using TreeModelBase as your superclass and just implementing the
abstract methods therein, then the implementation of the firstChild() method
is your opportunity to fetch the tree data lazily. This method will be
called on a node to "step down" one level in the tree, and it will only be
called for the nodes that are expanded. You should implement this method to
figure out what node the model is on at the moment, then use that
information to determine if you've already looked up that node's childre in
the backend system, or if you need to go and fetch ONLY the current node's
direct children. As the user descends through the tree, the tree will be
fleshed out and cached lazily, one level at a time, via this mechanism.
Does this make any sense?
Todd
To download the latest version of S1AF (JATO), please visit one of thefollowing locations:
>
Framework + IDE plugin for Sun ONE Studio 4 Update 1, Community Edition:
http://wwws.sun.com/software/download/products/Appl_Frmwk_2.0_CE.html
Framework + IDE pluign for Sun ONE Studio 4 Update 1, Enterprise Edition:
http://wwws.sun.com/software/download/products/Appl_Frmwk_2.0_EE.html
Previous versions of JATO:
http://www.sun.com/software/download/developer/5102.html
[Non-text portions of this message have been removed]

Vector does NOT implement Serializable

Hi :
can anyone think of a reason why Vector does not implement Serializable?
Suppose, I want to send a Vector of TimingResults accross a dataStream,
now TimingResult is a class that I created which does implement Serializable, yet I am getting erroneus results everytime ....

according to the 1.4.1 docs, Vector does implement the
Serializable interface.You are absolutely right...
sorry guys...my brain is fried this afternoon...

Capture a vector space

i want to capture a vector space (axis1&2),but when configure buffer ,the problem occur(see figure uploaded error -70006)..How should I modify in my procedure ?I am sure the board Id is configured right and the triggers are input correctly.

Configuring separate axis velocity/acceleration within a vector space

Is there a way to separately configure axis velocity/acceleration when using vector space motion control? My axes motivation are very diverse and I can not simply use a vector velocity/acceleration.

I guess that your application should not use Vector configuration then. The purpose of Vector Spaces is to group axes and define vector moves, the board will calculate each axis parameters in order to achieve the vector move.
If you require different velocity and acceleration per axis you might want to try to make up your own Vector algorithm in which for the eyes of the board you are treating each axis independently, but in your software you are actually grouping them. That is, you will configure each axis by its own, and you can do multi-starts and multi-stops. The Position/Velocity/Acceleration will be calculated by your own algorithm.
Good luck!
Nestor.
Nestor
National Instruments

Model implementation

Hi,
I am using CE 7.1. I am trying to use a RFC through model. When i try to write the below ocde, its giving error "the constructor Zbap_get_list_input is undefined".
Zbap_get_list_input objVariant = new Zbap_get_list_input();
Please help me.
Thanks in advance.

Hi Prasanthi,
Please try to re-import the model again and bind with the controllers.
then try sync source and build the DC and then try to create object of the RFC.
Refer to Undefined constructor and model nodes and constructor undefined , while initiating model node in component controller
Hope it wil helps
Regards
Arun

Creating an ES using the ProComp model, implementation

Dear,
I succesfully created my Enterprise Service, at least the definition part, and am now ready to implement it in SPROXY.
I'll probably just do an RFC to the R/3 system to retrieve some data and send that to the response of my Enterprise Service.
The synchronous service I have in SPROXY is (I'm presuming) the middle part after my request and before the return.
How do I go about implementing this, and how do I go about testing this?
Any guides, tips, help is much appreciated!
Thanks in advance,
Frederik-Jan

Hi,
I assume your scenario is RFC to Proxy, and you have done the service definition in ESR for both end.
The next steps to do in ID of PI are:
1. Create RFC sender adapter
2. Create Sender Agreement
3. Create Proxy receiver adapter, if there is none created before
4. Create Receiver Agreement
5. Create Interface Determination
The next steps to do in SPROXY of SAP back end system are:
1. Generate proxy class
2. Implement the method of the proxy
After that, you can start the testing.
Regards,
Lim...

Arc.vi 's input "Radius" is distance from arc centre or distance from vector space centre 0,0

Hi everybody,
I am using PXI 7352 +UMI+2 servo Drives+motors which move a table in linear direction X and rotate it along Z axis C.
How can I use Load Circular Arcvi if my one axis is linear and other is rotary e.g. XC table.
Thanks
Surender Kumar
Reckers Automation
Delhi

Surender,
You can run contours with an (almost) infinite number of position
points. The trick is to load new data into the buffer when it has
depleted to a certain amount of points. There is an example in LabVIEW
(Buffered Contouring (Rose).vi) that shows this method. Maybe there was
a bit confusion when you talke with NI India in terms of wording. There
are also onboard variables (about 100) but these are not used for
contouring. Contouring data is stored in an onboard buffer.
In contouring mode the board interpolates through the position points
stored in the buffer with a rate of 10 ms (minimum). Inbetween these
poionts the board interpolates using a cubic spline algorithm. In terms
of accuracy this method is equal to the arc move as arc moves use a
similar internal mechanism as contouring.
With contouring of course you could take care of the tool radius
compensation in your calculations but there is no ready to use solution
for that in LabVIEW. Maybe a 3rd party solution is available for that
(please refer to this thread which you should know
already).
Jochen

Search Relevance %

Hi,
In our defined KM Search, the results are sorted by relevance. But the relevance % doesn't go with the matches displayed in the document abstract. A high relevance % has 2 matches vs a lower relevance has 4 matches.
Does anyone know how the following:
1) How is this relevance % is calculated?
2) Is it solely related to the indexing done by TREX?
Any help would be much appreciated. PD We have Trex 6.0.
Regards

The TREX text-mining engine enhances the functions of TREX by reducing document content to meaningful words with the help of text operations such as reduction to root form, normalization of spelling, the removal of stop words, and so on. This improves retrieval results. The search results are refined because the relevance of the documents can be evaluated differentially. This is possible because the similarity between the documents is calculated on the basis of the tried and tested vector space model: Each document and term in the document set is represented by a multi-dimensional space. This representation allows TREX to carry out enhanced retrieval and classification methods. In this way, documents can be ordered sensibly according to certain criteria by being assigned automatically to a generic category or class (document classification). When a document is found, the user also receives a list of key words that give an overview of document content and help to characterize the document and distinguish it from others (determination of key words). The user can also look for documents that are similar to the one found. This helps to restrict the number of documents that may be relevant (Search for similar documents). TREX offers terms that are similar to the original search term in content and meaning. The user can then reformulate the search request (Search for similar terms).
Have a look at this [PDF Link|https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/81c1ca90-0201-0010-a2a1-b0412ec9cd1a]
Regards
BP

Vector Space Model implementation

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