There is only one object in question? Or will you later want to
generalize your method to other objects?
The object is presumably 3-dimensional. What then are the two
coordinates that you call x and y ? How are they defined with respect
to the object? (I presume they are not defined in terms of, say, the
room in which the object is placed, at least not if the object is small
enough to be picked up.) Why do you (appear to) ignore the third
dimension? (Is the object of a uniform thickness, perhaps, so that
its essential shape is two-dimensional rather than three-dimensional?
Or perhaps it has some other geometric regularity that renders two
dimensions sufficient for the exercise?
On Thu, 22 Jun 2000 [EMAIL PROTECTED] wrote:
> I need help with the following:
>
> I have a dataset with the positions of fingers on a certain object.
> We have the position of a particular point on each finger. For each
> finger, we pick the x and y coordinates of that point. Furthermore,
> we have 20 subjects and 5 trials per subject. So we have 100
> observations (20*5) and 10 variables ( x and y coordinates of 5
> particular points on each subject's finger).
>
> The objective is to find the number of sensors to put on this
> particular object and where to put them in order to maximize the
> discrimination between the subjects. In other words, where is the
> position of the best discriminating sensor? Where is the postion of
> the second best discriminating sensor? etc..., and when to stop
> adding sensors? (in other words, when it's not worthwile to add
> anymore sensors?)
You write of discrimination between Ss. Do you want to distinguish
between all 20 of them? (If so, why, for goodness' sake??) Or do you
want to distinguish between _Types_ of Ss, in some sense? What lurking
variables are you controlling for (or not): e.g., size of hand, age of
subject, sex of subject, relative lengths of fingers on the hand, ...?
> Any suggestions in how to proceed?
>
> The data looks like:
>
> ID Trial XT YT XI YI XM YM XR YR XP YP
>
> Id: id
> Trial: 1 to 5 (each subject holds the object 5 times)
> XT: x coordinate of the thumb
> YT: y coordinate of the thumb
> XI: x coordinate of the index
> YI: y coordinate of the index
> XM: x coordinate of the middle finger
> YM: y '' '' ''
> XR: x coordinate of the ring
> YR: y " "
> XP: x coordinate of the pinky
> YP: y coordiante of the pinky
------------------------------------------------------------------------
Donald F. Burrill [EMAIL PROTECTED]
348 Hyde Hall, Plymouth State College, [EMAIL PROTECTED]
MSC #29, Plymouth, NH 03264 603-535-2597
184 Nashua Road, Bedford, NH 03110 603-471-7128
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