For our investigation we have restricted the world to a stage

For our investiga= tion we have restricted the world to a stage. Action in the world is represented by the movement of one or more actors. Primarily the actor m= oves in accordance with a plan. The actor will also be using information from his eyes.

In the preceding = chapter we discussed a systems perspective, focusing on interfaces. For our initial research we will represent the world as a system with two subsystems: one for the optical information that flows to any viewers of what is happening on the stage. The other for the electric informa= tion that flows from neurons to muscles causing forces to be applied to each of = the bones that in turn cause each to rotate about its relevant joints. The resultant bone positions in the three dimensional space defined by the stage in turn provide the input to t= he optical subsystem.

= Simulating the optical subsystem for ‘the world’ on the stage

A requirement is = that the world should have no memory, i.e. the image depend only on the present mome= nt in time.

Another requireme= nt is that the actor should be visible to members of the audience, depending on t= heir seats, i.e. the location defining the viewing angle and distance. The actor should also be partially visible to himself if the eyes are directed appropriately.

A third requireme= nt is that the optical information is supplied on request, in response to a viewi= ng from a viewer.

The approach take= n is to utilize an SVG server (scaleable vector graphics) to respond to requests fr= om client browsers. An http comp= onent of this server requires that the viewer identify himself by indicating his location relative to the stage. This information is used to manage the response, i.e. to calculate t= he perspective.

The SVG server dr= aws on the known position of the actor’s bones in the 3 dimensional space associated with the stage. On= ly information for the current frame is kept and utilized, so that the model of the world does not require a memory of anything outside of the current frame.

= Simulating the mechanical subsystem for ‘the world’ on the stage

In our perspectiv= e, the bones, joints, and muscles of the actor belong to ‘the world’.<= span style=3D'mso-spacerun:yes'> The muscles, in turn, receive information from the brain of the actor through neurons. In this model, information is sent= for each instant in time (frame) to each of the muscles. It is this neural information that= is the input interface from the privacy of the actor’s brain to the publ= ic presence of muscles, joints, and bones in the world.

A requirement is = that the world have no memory, i.e. the bone positions depend only on the present mo= ment in time. The approach taken i= s that each bone has a position, and that only change information is supplied to t= he muscles to move then from the initial to the final position within the time= of the frame. For a true mechani= cal model this would deal with the effort required from the muscles, but we have simplified the model by only providing geometric change information.

Another requireme= nt is that there should be reasonable verisimilitude with respect to characterist= ics of bones and joints. We have simplified the bone structure by reducing the count and modeling them as straight. We try to respect t= he constraints of movement for the major bones and joints. In initial versions, bone and joint attributes are modeled in a generic fashion rather than being customized to each actor.

This subsystem is implemented in a browser – http-server arrangement, (i.e. client - server), where ‘the world’ is represented by an http server. The browser representing the brain requests a form from server that represents the world. That form lists the bones. The browser representing the brain= enters the requested change in joint angles for each bone. The information on this form is th= en uploaded to the server, and the bone positions are modified as per request (assuming the changes do not violate constraints).