Nexus

WebID authentication and subsequent visualization of the dereferenced WebID profile

Submitted by ebremer on

Up until now, I have not had any kind of authentication on Nexus.  I have tracked client sessions adding them as RDF statements in Nexus's system graph, but I had never bothered to validate who the user was.  Early last year, I fell in love with WebID.  What is WebID?  In a nutshell, it is public key encryption crossed with FOAF files in order to achieve password-less, single-sign on authentication.  It originally went under the monkier "FOAF+SSL".  A feature of WebID's public key design is that it does not require the normal key signing agents like Verisign and Godaddy.  For additional information, please see http://webid.info/.  There is also an excellent video by Manu Sporny on WebID.  WebID is being worked on by the WebID Community Group.  For this rest of this blog entry, I'm going to assume you watched and read up on WebID.

Now, how to add WebID to Nexus?  The first step was to create a WebID for myself.  Sadly, as much time as I have spent studying the Semantic Web, I had never created a FOAF file for myself.  My initial WebID profile was created using the following shell script https://gist.github.com/niclashoyer/2498494.  The resultant file was enriched with additional information about myself.  My newly created WebID profile can be seen at:
http://www.ebremer.com/foaf.rdf#me

If you think you foaf:know me, send me your URI and I will add you to my file (does anyone really foaf:know anyone?) ;-)

At this point, I now have my WebID profile and my private key (which contains my WebID URI) is stored in my browser.

The server coding was a bit more challanging.  Nexus's http/WebSocket engine is based on Jetty.  At the time I started coding the WebID authentication for Nexus, it was based on Jetty 8.  I created and installed a digital certificate for Jetty and got the WebSocket and http working over SSL.  This part was not difficult and only required flipping the "ws://" calls in the Nexus WebGL client to "wss://".  The current Jetty documentation worked fine for this.  The next step was to enable client certificate authentication and interrupt the normal client certificate validation chain in Java.  There are numerous examples of this all over the web where an "all-trusting" Java TrustManger is created to over-ride the default Trust Manager: 

	TrustManager[] trustAllCerts = new TrustManager[] { 
	      new X509TrustManager()
	      {
		 @Override
		 public X509Certificate[] getAcceptedIssuers()
		 {
			return null;
		 }
					
		 @Override
		 public void checkServerTrusted(X509Certificate[] chain, String authType)
			throws CertificateException
		 {
		 }
					
		 @Override
		 public void checkClientTrusted(X509Certificate[] chain, String authType)
			throws CertificateException
		 {
		 }
	    }

The pity was that most these examples were all wrong, well dated.  Why?  How?  I had upgraded my development environment to JDK 1.7.X from JDK 1.6.X. and after lots of reading, I discovered that the SSL was handled a bit differently in JDK 1.7.  You could no longer return null in the getAcceptedIssuers method.  It had to be written slightly different:

    public X509Certificate[] getAcceptedIssuers() {
        return new java.security.cert.X509Certificate[]{};
    }

With this change made, I could finally get the browser to pop up the client certificate list and then grab the WebID client certificate file server-side.  During the troubleshooting of getAcceptedIssuers, I upgraded Nexus's Jetty 8 to Jetty 9 M3 (now M5).  I also needed to modify three stock classes in Jetty 9 in order to pass the client WebID certificate to Nexus's WebSockets section.  The modifications are fairly simple but I did have to get a bit more intimate with Jetty's source code.  At the time of this blog entry, Jetty is now 9 RC0.  Once I got a handle on the submitted client certificate, I was able to dereference the WebID URI in the certificate and validate it's public key modulus and exponent against the dereferenced WebID file.

The above video, demonstrates the current login process for Nexus using WebID.  I do not have to visualize the dereferenced WebID profile, but I did so to test the authentication code and to demonstrate that you get more than just the client's WebID.  You also get things such as last name, first name, a client picture, contact information, and so on.

Changes

To date, I have been using N-TRIPLE RDF data streamed between the Nexus client and server over WebSockets.  I've flipped this to RDF Turtle over WebSockets.  Why? Better performance since Turtle allows for a more compact notation compressing more information into fewer bytes.  I've also discovered while reading up on UCC (unified communications and collaborations) for my campus, that the widely-used XMPP protocol (used for things like Google Talk) is nothing more than XML over http.  There is now work being done to have XMPP go over WebSockets (see spec) as opposed to http.  XMPP also uses JabberIDs (RFC 6122) as identifiers.  Personally, I prefer my Turtle RDF over WebSockets using WebID's for identifiers, but seeing XMPP gives me a sense of validation that the Turtle/WebSockets/WebID idea has merit.  In any case, see above video, it does work. :-)

Roadmap

Creation of WebID profiles - for now, you have to bring-your-own WebID to log onto Nexus which is absolutely fine.  However, I would like to be able to provide WebID profiles by Nexus as well for those who may want that feature.

I will also be adding alternate visualizations other than the ball-N-stick display.  One I will add soon is the representation of a foaf:Person as a cube instead of a sphere and then mapping that foaf:Person's foaf:img to the faces of the cube.  This will help provide a more visually compressed image.

The WebID work I am doing on Nexus will, in-part, be ported to VIVO.  VIVO is a web application that creates web profiles for researchers, their publications, grants, teachings, research interests, and so on.  VIVO does all of this on a foundation of RDF.  VIVO provides RDF profiles currently which should make is relatively easy to add the WebID components to it.  You can see the VIVO instance my Department has built for SUNY REACH here http://reach.suny.edu/.

Sample RDF data from WebID visualization (above) after layout is applied:

<http://shield.ebremer.com/resources/29bb010a-ac87-4b82-9171-c7c2b81793f8>
      a       <nex:cube> ;
      <nex:HoverText> "Erich Bremer" ;
      <nex:xyz> "6.757046,-3.423891,6.078216" .

<http://shield.ebremer.com/resources/fb33cb18-d2b7-4cd6-ad1b-dd4545dfe5ef>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://purl.org/dc/elements/1.1/creator" ;
      <nex:objxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:plen> "18.392017" ;
      <nex:rotation> "0.15562783 -0.0 0.7405087 0.653779" ;
      <nex:subjxyz> "18.789173,-6.010832,4.313797" ;
      <nex:xyz> "10.038619,-4.139514,2.194232" .

<http://shield.ebremer.com/resources/60fd2aea-37a7-4dbf-bbc2-c78cf60df689>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/birthday" ;
      <nex:objxyz> "-4.3850303,3.3814554,1.5917158" ;
      <nex:plen> "8.148866" ;
      <nex:rotation> "0.3897549 0.0 -0.23882553 0.88941187" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "-1.5484823,0.55662966,0.8331915" .

<http://xmlns.com/wordnet/1.6/Airport>
      <nex:rnode> <http://shield.ebremer.com/resources/b2df90a3-d67b-4496-ab74-0bd28dcb3f52> ;
      <nex:vnode> <http://shield.ebremer.com/resources/b2df90a3-d67b-4496-ab74-0bd28dcb3f52> .

<http://shield.ebremer.com/resources/ccf4eef8-837f-4277-b458-30aa04defa62>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/1999/02/22-rdf-syntax-ns#type" ;
      <nex:objxyz> "3.6347718,-25.323143,8.237062" ;
      <nex:plen> "7.2201514" ;
      <nex:rotation> "0.78663164 0.0 -0.45067078 -0.4220266" ;
      <nex:subjxyz> "1.9194171,-20.529259,3.117803" ;
      <nex:xyz> "2.7770944,-22.9262,5.677433" .

<http://shield.ebremer.com/resources/567ce25a-5c4c-421c-a815-ad5d8f892d8c>
      a       <nex:cylinder> ;
      <nex:HoverText> "nex:millitime" ;
      <nex:objxyz> "24.7447,-8.840323,1.3769542" ;
      <nex:plen> "7.217989" ;
      <nex:rotation> "0.9552735 0.0 0.2129643 -0.20517975" ;
      <nex:subjxyz> "18.789173,-6.010832,4.313797" ;
      <nex:xyz> "21.766937,-7.4255776,2.8453755" .

<http://shield.ebremer.com/nex/graphs/7203197c-a0b3-48a6-885c-d12e3598e86a>
      <nex:lnode> <http://shield.ebremer.com/resources/3680e5d4-ccce-48c8-be93-994c8039e2b9> ;
      <nex:pnode> <http://shield.ebremer.com/resources/db23a1f7-83eb-4402-8bbd-28a477393d88> ;
      <nex:vnode> <http://shield.ebremer.com/resources/db23a1f7-83eb-4402-8bbd-28a477393d88> , <http://shield.ebremer.com/resources/3680e5d4-ccce-48c8-be93-994c8039e2b9> .

<http://shield.ebremer.com/resources/89548bed-ce50-401e-846b-3fa2632b24fd>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/accountServiceHomepage" ;
      <nex:objxyz> "13.079804,11.690309,-15.968671" ;
      <nex:plen> "7.182698" ;
      <nex:rotation> "0.715777 -0.0 0.5695869 0.40402234" ;
      <nex:subjxyz> "12.902582,7.535981,-10.111939" ;
      <nex:xyz> "12.991194,9.613145,-13.040305" .

<http://shield.ebremer.com/sessions/5d24b75c-7325-4122-9cf3-cf9c8708a534>
      a       <nex:clientsession> ;
      <http://purl.org/dc/elements/1.1/creator>
              <http://www.ebremer.com/foaf.rdf#me> ;
      <nex:ip4> "68.195.227.26" ;
      <nex:millitime> "1360634398601" ;
      <nex:rnode> <http://shield.ebremer.com/resources/98cfdf87-8afa-438d-aeeb-715349442223> ;
      <nex:vnode> <http://shield.ebremer.com/resources/98cfdf87-8afa-438d-aeeb-715349442223> .

<http://shield.ebremer.com/resources/1d3c6e2f-d152-4907-b29e-c3262a9e4fa9>
      a       <nex:cube> ;
      <nex:HoverText> "99" ;
      <nex:xyz> "-13.684594,19.697659,-7.6601453" .

<http://shield.ebremer.com/resources/b2adefe1-d185-48bd-ad43-12d36ae6812e>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.daml.org/2001/10/html/airport-ont#iataCode" ;
      <nex:objxyz> "-13.065482,20.259962,5.5250096" ;
      <nex:plen> "6.9649067" ;
      <nex:rotation> "0.7950134 0.0 -0.575792 0.19083306" ;
      <nex:subjxyz> "-14.904862,18.146603,-0.8515341" ;
      <nex:xyz> "-13.985172,19.203281,2.3367376" .

<http://shield.ebremer.com/resources/ce47d7b7-02d2-491a-8a80-3fc723c21fa7>
      a       <nex:cube> ;
      <nex:HoverText> "ISP" ;
      <nex:xyz> "-13.065482,20.259962,5.5250096" .

<http://shield.ebremer.com/nex/graphs/7bac972c-0aa8-48a1-ba8f-8e608bd26922>
      <nex:pnode> <http://shield.ebremer.com/resources/8eff4274-4595-4556-8b5c-b56309bd0d8c> ;
      <nex:vnode> <http://shield.ebremer.com/resources/8eff4274-4595-4556-8b5c-b56309bd0d8c> .

<http://shield.ebremer.com/resources/a4c68454-8597-4efd-8b3a-3328068aa5a9>
      a       <nex:cube> ;
      <nex:HoverText> "MacArthur Airport" ;
      <nex:xyz> "-17.589022,25.33923,-4.8700905" .

<http://shield.ebremer.com/resources/bd6d61f7-32cf-41c3-97ce-d10e88baba18>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/primaryTopic" ;
      <nex:objxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:plen> "10.131038" ;
      <nex:rotation> "0.97251564 -0.0 0.11701429 0.20129848" ;
      <nex:subjxyz> "-7.744496,-6.2348194,2.3804553" ;
      <nex:xyz> "-3.2282152,-4.2515078,1.2275612" .

<http://shield.ebremer.com/nex/graphs/329bd0e1-e559-49ff-bdef-ef2c20b6cd65>
      <nex:pnode> <http://shield.ebremer.com/resources/6eaa9557-cb96-49d0-ab66-18c57c097404> ;
      <nex:vnode> <http://shield.ebremer.com/resources/6eaa9557-cb96-49d0-ab66-18c57c097404> .

<http://shield.ebremer.com/resources/bcc8f0a5-e903-4fc2-83e5-3b3d2b774669>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/knows" ;
      <nex:objxyz> "-1.3737096,-9.053491,-14.856207" ;
      <nex:plen> "16.61494" ;
      <nex:rotation> "0.64799553 0.0 0.693401 -0.31511417" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "-0.042821944,-5.6608434,-7.39077" .

<http://www.rpi.edu>
      <nex:rnode> <http://shield.ebremer.com/resources/a59dd00a-e501-4c76-ac18-de0141a3f0d4> ;
      <nex:vnode> <http://shield.ebremer.com/resources/a59dd00a-e501-4c76-ac18-de0141a3f0d4> .

<http://xmlns.com/foaf/0.1/OnlineAccount>
      <nex:rnode> <http://shield.ebremer.com/resources/94e333ba-d4c1-43c9-883a-43a432b84e03> ;
      <nex:vnode> <http://shield.ebremer.com/resources/94e333ba-d4c1-43c9-883a-43a432b84e03> .

<http://shield.ebremer.com/resources/3680e5d4-ccce-48c8-be93-994c8039e2b9>
      a       <nex:cube> ;
      <nex:HoverText> 65537 ;
      <nex:xyz> "-2.369653,-26.378757,3.3365998" .

<http://shield.ebremer.com/resources/8fe9f157-afdc-45fe-a669-c2f51de7e7a5>
      a       <nex:sphere> ;
      <nex:HoverText> "mailto:erich@ebremer.com" ;
      <nex:xyz> "2.5592043,6.2678094,-1.043553" .

<http://shield.ebremer.com/nex/graphs/d27be237-da93-4c84-b04f-3955298d5916>
      <nex:pnode> <http://shield.ebremer.com/resources/4c7d190d-c4f4-4c01-85b4-f91d0a54099a> ;
      <nex:vnode> <http://shield.ebremer.com/resources/4c7d190d-c4f4-4c01-85b4-f91d0a54099a> .

<http://shield.ebremer.com/nex/graphs/f1dbdd3f-230b-4003-9921-4438619affe9>
      <nex:pnode> <http://shield.ebremer.com/resources/ccf4eef8-837f-4277-b458-30aa04defa62> ;
      <nex:vnode> <http://shield.ebremer.com/resources/ccf4eef8-837f-4277-b458-30aa04defa62> .

<http://shield.ebremer.com/resources/4c7d190d-c4f4-4c01-85b4-f91d0a54099a>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/1999/02/22-rdf-syntax-ns#type" ;
      <nex:objxyz> "-10.496608,24.227457,-1.1073451" ;
      <nex:plen> "7.514981" ;
      <nex:rotation> "0.8906727 -0.0 0.01910923 0.45424342" ;
      <nex:subjxyz> "-14.904862,18.146603,-0.8515341" ;
      <nex:xyz> "-12.700735,21.18703,-0.9794396" .

<http://shield.ebremer.com/resources/9c1059d0-aa65-4f7b-86c6-3d1b25ba7bf7>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/mbox" ;
      <nex:objxyz> "2.5592043,6.2678094,-1.043553" ;
      <nex:plen> "8.702275" ;
      <nex:rotation> "0.7569907 -0.0 0.08487387 0.6478901" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "1.923635,1.9998066,-0.48444292" .

<http://shield.ebremer.com/nex/graphs/288cc48b-e1e3-4f70-89d7-d9f5d15516ed>
      <nex:pnode> <http://shield.ebremer.com/resources/8f9ae0ed-a856-4892-b679-a8bfed744e44> ;
      <nex:vnode> <http://shield.ebremer.com/resources/8f9ae0ed-a856-4892-b679-a8bfed744e44> .

<http://shield.ebremer.com/resources/c7954db7-d627-4cc3-9c3c-38dc35e18d51>
      a       <nex:cube> ;
      <nex:HoverText> "1968-04-22" ;
      <nex:xyz> "-4.3850303,3.3814554,1.5917158" .

<http://shield.ebremer.com/resources/c4107112-7c4d-4f45-b6a0-727e0d2c1fc5>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/img" ;
      <nex:objxyz> "0.9335052,-8.212778,5.893996" ;
      <nex:plen> "8.3263645" ;
      <nex:rotation> "0.6918877 0.0 -0.5050704 -0.5159413" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "1.1107855,-5.240487,2.9843314" .

<http://shield.ebremer.com/nex/graphs/f4ae2cdd-0c15-43b3-ab4e-c1908574e05c>
      <nex:pnode> <http://shield.ebremer.com/resources/6b9c8582-487c-42d9-8298-e9cc51762d2f> ;
      <nex:vnode> <http://shield.ebremer.com/resources/6b9c8582-487c-42d9-8298-e9cc51762d2f> .

<http://shield.ebremer.com/resources/9a016505-55fc-40e1-bbe0-5895319289be>
      a       <nex:cube> ;
      <nex:HoverText> "Erich Bremer's profile" ;
      <nex:xyz> "-13.243382,-8.80005,7.3699355" .

<http://shield.ebremer.com/nex/graphs/eba969cf-cc66-499d-90ce-634771c379d2>
      <nex:pnode> <http://shield.ebremer.com/resources/c4107112-7c4d-4f45-b6a0-727e0d2c1fc5> ;
      <nex:vnode> <http://shield.ebremer.com/resources/c4107112-7c4d-4f45-b6a0-727e0d2c1fc5> .

<http://shield.ebremer.com/nex/graphs/b381ebe9-2a45-4c94-b4ff-09b871cc9f98>
      <nex:lnode> <http://shield.ebremer.com/resources/1d3c6e2f-d152-4907-b29e-c3262a9e4fa9> ;
      <nex:pnode> <http://shield.ebremer.com/resources/bb45dfba-9062-496e-9035-e8d4e9454ee4> ;
      <nex:vnode> <http://shield.ebremer.com/resources/1d3c6e2f-d152-4907-b29e-c3262a9e4fa9> , <http://shield.ebremer.com/resources/bb45dfba-9062-496e-9035-e8d4e9454ee4> .

<http://shield.ebremer.com/nex/graphs/d4a989d0-d6dc-4a52-a9c7-c574ab1ec856>
      <nex:pnode> <http://shield.ebremer.com/resources/9e449a77-55e3-4aab-a281-225071956f18> ;
      <nex:vnode> <http://shield.ebremer.com/resources/9e449a77-55e3-4aab-a281-225071956f18> .

<http://shield.ebremer.com/resources/9486c237-8fe4-4f7a-a121-d32288e22bdb>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/1999/02/22-rdf-syntax-ns#type" ;
      <nex:objxyz> "-0.31521404,-6.5853963,-9.528153" ;
      <nex:plen> "5.966578" ;
      <nex:rotation> "0.7672692 0.0 -0.58192295 0.26956198" ;
      <nex:subjxyz> "-1.3737096,-9.053491,-14.856207" ;
      <nex:xyz> "-0.8444618,-7.8194437,-12.192181" .

<http://shield.ebremer.com/resources/94e333ba-d4c1-43c9-883a-43a432b84e03>
      a       <nex:sphere> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/OnlineAccount" ;
      <nex:xyz> "18.817831,6.775251,-14.205012" .

<http://shield.ebremer.com/resources/bb08e58a-655b-4920-b5ee-1588914ae382>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/family_name" ;
      <nex:objxyz> "-1.0298611,-9.309256,-1.8062805" ;
      <nex:plen> "7.647697" ;
      <nex:rotation> "0.59030145 0.0 0.20832536 -0.7798363" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "0.12910229,-5.788726,-0.8658067" .

<http://shield.ebremer.com/nex/graphs/1ccc0a38-5e58-499c-99b7-6a21b72b70d1>
      <nex:lnode> <http://shield.ebremer.com/resources/d2ce17d5-c4cd-434f-8c78-7fe5e9b79fff> ;
      <nex:pnode> <http://shield.ebremer.com/resources/1b5e3f92-4346-45b9-9bcd-8a1200f751e2> ;
      <nex:vnode> <http://shield.ebremer.com/resources/d2ce17d5-c4cd-434f-8c78-7fe5e9b79fff> , <http://shield.ebremer.com/resources/1b5e3f92-4346-45b9-9bcd-8a1200f751e2> .

<http://shield.ebremer.com/nex/graphs/0aa6ac74-225a-468f-86ce-81e54424d0f9>
      <nex:lnode> <http://shield.ebremer.com/resources/051b6934-d1d3-493a-b8b7-6d6547204aa6> ;
      <nex:pnode> <http://shield.ebremer.com/resources/9eaad767-89c0-44eb-bd3f-3d764dfea398> ;
      <nex:vnode> <http://shield.ebremer.com/resources/9eaad767-89c0-44eb-bd3f-3d764dfea398> , <http://shield.ebremer.com/resources/051b6934-d1d3-493a-b8b7-6d6547204aa6> .

<http://shield.ebremer.com/nex/graphs/5048521a-dc4f-488c-b926-0c4354779b98>
      <nex:lnode> <http://shield.ebremer.com/resources/5997861f-a88d-479d-8e2a-52a701c49cb1> ;
      <nex:pnode> <http://shield.ebremer.com/resources/567ce25a-5c4c-421c-a815-ad5d8f892d8c> ;
      <nex:vnode> <http://shield.ebremer.com/resources/5997861f-a88d-479d-8e2a-52a701c49cb1> , <http://shield.ebremer.com/resources/567ce25a-5c4c-421c-a815-ad5d8f892d8c> .

<http://shield.ebremer.com/resources/a6f011f3-fb26-4cd3-ae74-1738843268de>
      a       <nex:cube> ;
      <nex:HoverText> "Erich" ;
      <nex:xyz> "6.9691315,-3.1183655,-5.7980638" .

<http://shield.ebremer.com/nex/graphs/7758c5a1-86d0-4582-9d61-052ec69ba209>
      <nex:lnode> <http://shield.ebremer.com/resources/92f18885-f7cb-4b4b-8e64-ae07ba8e127c> ;
      <nex:pnode> <http://shield.ebremer.com/resources/69d0c361-57e6-4ea2-b353-c14a12de84e1> ;
      <nex:vnode> <http://shield.ebremer.com/resources/69d0c361-57e6-4ea2-b353-c14a12de84e1> , <http://shield.ebremer.com/resources/92f18885-f7cb-4b4b-8e64-ae07ba8e127c> .

<http://shield.ebremer.com/resources/9eaad767-89c0-44eb-bd3f-3d764dfea398>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/2003/01/geo/wgs84_pos#long" ;
      <nex:objxyz> "6.546685,1.1909465,23.601688" ;
      <nex:plen> "7.2011604" ;
      <nex:rotation> "0.89797086 0.0 -0.40392396 0.1746243" ;
      <nex:subjxyz> "2.134508,-1.0674458,18.377794" ;
      <nex:xyz> "4.3405967,0.061750352,20.989742" .

<http://shield.ebremer.com/resources/a1e381fd-5527-4cba-a92c-9174792ca6a2>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/1999/02/22-rdf-syntax-ns#type" ;
      <nex:objxyz> "18.817831,6.775251,-14.205012" ;
      <nex:plen> "7.233403" ;
      <nex:rotation> "0.9533542 0.0 0.2967717 -0.05515739" ;
      <nex:subjxyz> "12.902582,7.535981,-10.111939" ;
      <nex:xyz> "15.860207,7.155616,-12.158476" .

<http://shield.ebremer.com/resources/77915d2a-0bef-4f82-bab3-9bf5a1e38998>
      a       <nex:cube> ;
      <nex:HoverText> "erich.bremer" ;
      <nex:xyz> "17.448757,13.079433,-9.482868" .

<http://xmlns.com/foaf/0.1/PersonalProfileDocument>
      <nex:rnode> <http://shield.ebremer.com/resources/b3adf0db-7020-4ef7-b279-9b5188171c26> ;
      <nex:vnode> <http://shield.ebremer.com/resources/b3adf0db-7020-4ef7-b279-9b5188171c26> .

<http://www.w3.org/2003/01/geo/wgs84_pos#Point>
      <nex:rnode> <http://shield.ebremer.com/resources/fe02cb3e-5e78-4345-8ffd-dc664eb00162> ;
      <nex:vnode> <http://shield.ebremer.com/resources/fe02cb3e-5e78-4345-8ffd-dc664eb00162> .

<http://shield.ebremer.com/nex/graphs/b3af923a-b650-4f6d-8842-99ba66ed16d4>
      <nex:pnode> <http://shield.ebremer.com/resources/c80a1c26-be88-4859-a97b-155acb835e1f> ;
      <nex:vnode> <http://shield.ebremer.com/resources/c80a1c26-be88-4859-a97b-155acb835e1f> .

<http://shield.ebremer.com/nex/graphs/edf8b9b1-43b0-495b-9928-69cb6163b613>
      <nex:lnode> <http://shield.ebremer.com/resources/4adc5dcd-ddf4-4592-9e54-0c0686dd8f9b> ;
      <nex:pnode> <http://shield.ebremer.com/resources/857ad6b4-8dca-4304-aaaf-60f97a304f51> ;
      <nex:vnode> <http://shield.ebremer.com/resources/4adc5dcd-ddf4-4592-9e54-0c0686dd8f9b> , <http://shield.ebremer.com/resources/857ad6b4-8dca-4304-aaaf-60f97a304f51> .

<http://shield.ebremer.com/resources/b2df90a3-d67b-4496-ab74-0bd28dcb3f52>
      a       <nex:sphere> ;
      <nex:HoverText> "http://xmlns.com/wordnet/1.6/Airport" ;
      <nex:xyz> "-10.496608,24.227457,-1.1073451" .

<http://xmlns.com/foaf/0.1/Person>
      <nex:rnode> <http://shield.ebremer.com/resources/f6bdf9f1-7650-4da8-b376-241ef12e7bcb> ;
      <nex:vnode> <http://shield.ebremer.com/resources/f6bdf9f1-7650-4da8-b376-241ef12e7bcb> .

<http://shield.ebremer.com/nex/graphs/39dd280a-547f-490a-822e-88dd02ea1306>
      <nex:pnode> <http://shield.ebremer.com/resources/292e2152-f326-4417-9ede-b77864831e4a> ;
      <nex:vnode> <http://shield.ebremer.com/resources/292e2152-f326-4417-9ede-b77864831e4a> .

<http://shield.ebremer.com/nex/graphs/9dc0d1ad-c8f1-445b-9efd-6e5dafff46f1>
      <nex:lnode> <http://shield.ebremer.com/resources/77915d2a-0bef-4f82-bab3-9bf5a1e38998> ;
      <nex:pnode> <http://shield.ebremer.com/resources/1b686e0b-95b8-469b-ad05-ae5c0abf6a03> ;
      <nex:vnode> <http://shield.ebremer.com/resources/1b686e0b-95b8-469b-ad05-ae5c0abf6a03> , <http://shield.ebremer.com/resources/77915d2a-0bef-4f82-bab3-9bf5a1e38998> .

<http://shield.ebremer.com/resources/8d846a2a-1bb0-4a85-bbbd-941caba6cce4>
      a       <nex:cylinder> ;
      <nex:HoverText> "nex:ip4" ;
      <nex:objxyz> "22.810303,-9.893983,8.884933" ;
      <nex:plen> "7.221055" ;
      <nex:rotation> "0.8822873 0.0 -0.35874307 -0.30474994" ;
      <nex:subjxyz> "18.789173,-6.010832,4.313797" ;
      <nex:xyz> "20.799738,-7.9524074,6.599365" .

<http://shield.ebremer.com/resources/f6bdf9f1-7650-4da8-b376-241ef12e7bcb>
      a       <nex:sphere> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/Person" ;
      <nex:xyz> "-0.31521404,-6.5853963,-9.528153" .

<http://shield.ebremer.com/resources/66172254-f3cf-4223-859c-1dedec337a45>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/1999/02/22-rdf-syntax-ns#type" ;
      <nex:objxyz> "-14.76252,-9.281522,0.552921" ;
      <nex:plen> "7.8660626" ;
      <nex:rotation> "0.23217401 0.0 0.5003387 -0.83412015" ;
      <nex:subjxyz> "-7.744496,-6.2348194,2.3804553" ;
      <nex:xyz> "-11.253508,-7.7581706,1.4666882" .

<http://shield.ebremer.com/nex/graphs/4526ae0f-0e48-41ba-8d1e-42a6b07916ee>
      <nex:pnode> <http://shield.ebremer.com/resources/ed15e725-1eb6-4189-9895-11ae2a47cdad> ;
      <nex:vnode> <http://shield.ebremer.com/resources/ed15e725-1eb6-4189-9895-11ae2a47cdad> .

<http://shield.ebremer.com/resources/d7df5776-3106-45ab-a138-f370afa01cd2>
      a       <nex:sphere> ;
      <nex:HoverText> "http://tdiprima.com/foaf.rdf#me" ;
      <nex:xyz> "-6.128773,-8.901025,-20.684343" .

<http://www.w3.org/ns/auth/cert#RSAPublicKey>
      <nex:rnode> <http://shield.ebremer.com/resources/a6e56026-c5bd-4331-ab7a-20b0f1c8660a> ;
      <nex:vnode> <http://shield.ebremer.com/resources/a6e56026-c5bd-4331-ab7a-20b0f1c8660a> .

<http://shield.ebremer.com/resources/c35ce390-4f59-4f99-9cec-fa3b041d5614>
      a       <nex:sphere> ;
      <nex:nodesize> "4" ;
      <nex:numlinks> "4" ;
      <nex:q> "4" ;
      <nex:xyz> "-1.3737096,-9.053491,-14.856207" .

<mailto:tammy.diprima@stonybrook.edu>
      <nex:rnode> <http://shield.ebremer.com/resources/a6ff1888-c243-4126-acbf-b44c651855b0> ;
      <nex:vnode> <http://shield.ebremer.com/resources/a6ff1888-c243-4126-acbf-b44c651855b0> .

<http://shield.ebremer.com/resources/66ded436-abb8-43d8-b8c4-ad4b016544fc>
      a       <nex:cube> ;
      <nex:HoverText> "40.789278" ;
      <nex:xyz> "-20.15058,16.152966,3.8811495" .

<http://shield.ebremer.com/resources/ed15e725-1eb6-4189-9895-11ae2a47cdad>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/schoolHomepage" ;
      <nex:objxyz> "-2.4844422,-1.1644895,7.222489" ;
      <nex:plen> "8.157288" ;
      <nex:rotation> "0.51842505 0.0 -0.84510744 0.13049439" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "-0.5981883,-1.7163428,3.648578" .

<http://shield.ebremer.com/resources/292e2152-f326-4417-9ede-b77864831e4a>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/maker" ;
      <nex:objxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:plen> "10.131038" ;
      <nex:rotation> "0.97251564 -0.0 0.11701429 0.20129848" ;
      <nex:subjxyz> "-7.744496,-6.2348194,2.3804553" ;
      <nex:xyz> "-3.2282152,-4.2515078,1.2275612" .

<http://shield.ebremer.com/nex/graphs/08915ade-c3e3-49bd-954a-de7de9ec72bf>
      <nex:pnode> <http://shield.ebremer.com/resources/9c1059d0-aa65-4f7b-86c6-3d1b25ba7bf7> ;
      <nex:vnode> <http://shield.ebremer.com/resources/9c1059d0-aa65-4f7b-86c6-3d1b25ba7bf7> .

<http://shield.ebremer.com/resources/583634b9-1410-4e35-8bbc-40a12317ac72>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/title" ;
      <nex:objxyz> "-13.243382,-8.80005,7.3699355" ;
      <nex:plen> "7.855767" ;
      <nex:rotation> "0.38731062 0.0 -0.8199309 -0.42154926" ;
      <nex:subjxyz> "-7.744496,-6.2348194,2.3804553" ;
      <nex:xyz> "-10.493939,-7.5174346,4.8751955" .

<http://shield.ebremer.com/resources/1b686e0b-95b8-469b-ad05-ae5c0abf6a03>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/accountName" ;
      <nex:objxyz> "17.448757,13.079433,-9.482868" ;
      <nex:plen> "7.1967564" ;
      <nex:rotation> "0.90324354 0.0 -0.048386943 0.42639163" ;
      <nex:subjxyz> "12.902582,7.535981,-10.111939" ;
      <nex:xyz> "15.17567,10.307707,-9.797403" .

<http://shield.ebremer.com/resources/c5a8ee68-26e2-4f8e-af3a-239042d5cf27>
      a       <nex:cube> ;
      <nex:HoverText> "Bremer" ;
      <nex:xyz> "-1.0298611,-9.309256,-1.8062805" .

<http://www.skype.com/>
      <nex:rnode> <http://shield.ebremer.com/resources/322e2c62-2466-4250-82d0-95bd38dea1f8> ;
      <nex:vnode> <http://shield.ebremer.com/resources/322e2c62-2466-4250-82d0-95bd38dea1f8> .

<http://shield.ebremer.com/nex/graphs/7e755837-bd55-4ae4-af08-4211fe6ab667>
      <nex:pnode> <http://shield.ebremer.com/resources/b703c2aa-c634-46b0-85e6-96cb3c94d34b> ;
      <nex:vnode> <http://shield.ebremer.com/resources/b703c2aa-c634-46b0-85e6-96cb3c94d34b> .

<http://shield.ebremer.com/nex/graphs/0416566b-2173-4e4a-a516-509c868f6aca>
      <nex:pnode> <http://shield.ebremer.com/resources/9486c237-8fe4-4f7a-a121-d32288e22bdb> ;
      <nex:vnode> <http://shield.ebremer.com/resources/9486c237-8fe4-4f7a-a121-d32288e22bdb> .

<http://shield.ebremer.com/nex/graphs/7271f99f-b4df-45ec-a9ba-08f55f6a5764>
      <nex:lnode> <http://shield.ebremer.com/resources/b923152a-8efc-4ff2-9dba-1d1abdedab44> ;
      <nex:pnode> <http://shield.ebremer.com/resources/35f94abd-847a-490a-86eb-22f2e3726060> ;
      <nex:vnode> <http://shield.ebremer.com/resources/35f94abd-847a-490a-86eb-22f2e3726060> , <http://shield.ebremer.com/resources/b923152a-8efc-4ff2-9dba-1d1abdedab44> .

<http://shield.ebremer.com/resources/1b5e3f92-4346-45b9-9bcd-8a1200f751e2>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.daml.org/2001/10/html/airport-ont#longitude" ;
      <nex:objxyz> "-23.10833,20.7913,-1.7015207" ;
      <nex:plen> "8.66105" ;
      <nex:rotation> "0.16253012 -0.0 0.3019099 0.9393798" ;
      <nex:subjxyz> "-14.904862,18.146603,-0.8515341" ;
      <nex:xyz> "-19.006596,19.468952,-1.2765274" .

<http://shield.ebremer.com/nex/graphs/af7c2a2c-c4db-475a-99fd-94613fc1a5a7>
      <nex:pnode> <http://shield.ebremer.com/resources/89548bed-ce50-401e-846b-3fa2632b24fd> ;
      <nex:vnode> <http://shield.ebremer.com/resources/89548bed-ce50-401e-846b-3fa2632b24fd> .

<http://shield.ebremer.com/resources/58b36f00-9c37-4888-849a-fe8485ddbe3c>
      a       <nex:sphere> ;
      <nex:nodesize> "3" ;
      <nex:numlinks> "3" ;
      <nex:q> "3" ;
      <nex:xyz> "1.9194171,-20.529259,3.117803" .

<http://shield.ebremer.com/nex/graphs/762e5172-5fd0-4520-a9c0-4c4d085979d6>
      <nex:lnode> <http://shield.ebremer.com/resources/a6f011f3-fb26-4cd3-ae74-1738843268de> ;
      <nex:pnode> <http://shield.ebremer.com/resources/58ec8462-762e-4982-a46e-6737b8254dfb> ;
      <nex:vnode> <http://shield.ebremer.com/resources/58ec8462-762e-4982-a46e-6737b8254dfb> , <http://shield.ebremer.com/resources/a6f011f3-fb26-4cd3-ae74-1738843268de> .

<http://shield.ebremer.com/resources/f9ba89b7-fe3d-43a8-bc80-018e0b18e8a2>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/2003/01/geo/wgs84_pos#lat" ;
      <nex:objxyz> "1.8440512,-5.244094,24.264164" ;
      <nex:plen> "7.223441" ;
      <nex:rotation> "0.69274443 0.0 -0.58816665 -0.41733107" ;
      <nex:subjxyz> "2.134508,-1.0674458,18.377794" ;
      <nex:xyz> "1.9892795,-3.1557698,21.32098" .

<http://shield.ebremer.com/resources/857ad6b4-8dca-4304-aaaf-60f97a304f51>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/title" ;
      <nex:objxyz> "8.727002,1.4348108,0.31527075" ;
      <nex:plen> "8.313117" ;
      <nex:rotation> "0.9733558 0.0 -0.014867452 0.22881734" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "5.007534,-0.41669267,0.19496895" .

<http://shield.ebremer.com/nex/graphs/ef301870-a995-46b8-8a4f-5de6569e7e32>
      <nex:pnode> <http://shield.ebremer.com/resources/66172254-f3cf-4223-859c-1dedec337a45> ;
      <nex:vnode> <http://shield.ebremer.com/resources/66172254-f3cf-4223-859c-1dedec337a45> .

<http://www.ebremer.com/ebfiles/erich.jpg>
      <nex:rnode> <http://shield.ebremer.com/resources/e2ac006c-0dfe-42d8-b140-9941afc549c8> ;
      <nex:vnode> <http://shield.ebremer.com/resources/e2ac006c-0dfe-42d8-b140-9941afc549c8> .

<http://shield.ebremer.com/resources/8f9ae0ed-a856-4892-b679-a8bfed744e44>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/1999/02/22-rdf-syntax-ns#type" ;
      <nex:objxyz> "-1.2423172,1.9353592,23.958439" ;
      <nex:plen> "7.1807647" ;
      <nex:rotation> "0.51465523 0.0 -0.7550353 0.4062656" ;
      <nex:subjxyz> "2.134508,-1.0674458,18.377794" ;
      <nex:xyz> "0.44609535,0.43395674,21.168118" .

<http://shield.ebremer.com/nex/graphs/59c7440e-990b-4ade-a872-1b3abfe57c8d>
      <nex:lnode> <http://shield.ebremer.com/resources/027fd95a-b962-4f27-8634-a61fd7f3741d> ;
      <nex:pnode> <http://shield.ebremer.com/resources/6bdc1b94-5bff-4e96-a39e-fe04be1d1f79> ;
      <nex:vnode> <http://shield.ebremer.com/resources/027fd95a-b962-4f27-8634-a61fd7f3741d> , <http://shield.ebremer.com/resources/6bdc1b94-5bff-4e96-a39e-fe04be1d1f79> .

<http://shield.ebremer.com/resources/6bdc1b94-5bff-4e96-a39e-fe04be1d1f79>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/ns/auth/cert#modulus" ;
      <nex:objxyz> "5.035039,-26.519365,0.5492316" ;
      <nex:plen> "7.2239904" ;
      <nex:rotation> "0.8459575 0.0 0.21015319 -0.49009344" ;
      <nex:subjxyz> "1.9194171,-20.529259,3.117803" ;
      <nex:xyz> "3.4772282,-23.524311,1.8335173" .

<http://tdiprima.com/foaf.rdf#me>
      <nex:rnode> <http://shield.ebremer.com/resources/d7df5776-3106-45ab-a138-f370afa01cd2> ;
      <nex:vnode> <http://shield.ebremer.com/resources/d7df5776-3106-45ab-a138-f370afa01cd2> .

<http://shield.ebremer.com/nex/graphs/04700542-5082-40dc-bd39-dc3adc9dbcc7>
      <nex:lnode> <http://shield.ebremer.com/resources/66ded436-abb8-43d8-b8c4-ad4b016544fc> ;
      <nex:pnode> <http://shield.ebremer.com/resources/007e136b-e05a-4061-b70e-1db5127a42b2> ;
      <nex:vnode> <http://shield.ebremer.com/resources/007e136b-e05a-4061-b70e-1db5127a42b2> , <http://shield.ebremer.com/resources/66ded436-abb8-43d8-b8c4-ad4b016544fc> .

<http://shield.ebremer.com/nex/graphs/46ea5446-2766-477a-b8d4-5aa50c506fc0>
      <nex:lnode> <http://shield.ebremer.com/resources/a4c68454-8597-4efd-8b3a-3328068aa5a9> ;
      <nex:pnode> <http://shield.ebremer.com/resources/feb37eec-a3b8-48ba-9bd1-780baa0923c5> ;
      <nex:vnode> <http://shield.ebremer.com/resources/feb37eec-a3b8-48ba-9bd1-780baa0923c5> , <http://shield.ebremer.com/resources/a4c68454-8597-4efd-8b3a-3328068aa5a9> .

<http://shield.ebremer.com/resources/7a62ac94-793e-4bba-8a72-6cfae00b86b1>
      a       <nex:cube> ;
      <nex:HoverText> "KISMP" ;
      <nex:xyz> "-19.809538,15.09504,-5.055586" .

<http://www.ebremer.com/foaf.rdf#me>
      a       <http://xmlns.com/foaf/0.1/Person> ;
      <http://www.w3.org/2000/10/swap/pim/contact#nearestAirport>
              [ a       <http://xmlns.com/wordnet/1.6/Airport> ;
                <http://www.daml.org/2001/10/html/airport-ont#elevation>
                        "99" ;
                <http://www.daml.org/2001/10/html/airport-ont#iataCode>
                        "ISP" ;
                <http://www.daml.org/2001/10/html/airport-ont#icaoCode>
                        "KISMP" ;
                <http://www.daml.org/2001/10/html/airport-ont#latitude>
                        "40.789278" ;
                <http://www.daml.org/2001/10/html/airport-ont#location>
                        "Islip, New York, United States" ;
                <http://www.daml.org/2001/10/html/airport-ont#longitude>
                        "-73.097545" ;
                <http://www.daml.org/2001/10/html/airport-ont#name>
                        "MacArthur Airport" ;
                <nex:rnode> <http://shield.ebremer.com/resources/b6ecaf9e-d9fe-44f8-bd45-9188fec00d0b> ;
                <nex:vnode> <http://shield.ebremer.com/resources/b6ecaf9e-d9fe-44f8-bd45-9188fec00d0b>
              ] ;
      <http://www.w3.org/ns/auth/cert#key>
              [ a       <http://www.w3.org/ns/auth/cert#RSAPublicKey> ;
                <http://www.w3.org/ns/auth/cert#exponent>
                        65537 ;
                <http://www.w3.org/ns/auth/cert#modulus>
                       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http://www.w3.org/2001/XMLSchema#hexBinary> ;
                <nex:rnode> <http://shield.ebremer.com/resources/58b36f00-9c37-4888-849a-fe8485ddbe3c> ;
                <nex:vnode> <http://shield.ebremer.com/resources/58b36f00-9c37-4888-849a-fe8485ddbe3c>
              ] ;
      <http://xmlns.com/foaf/0.1/based_near>
              [ a       <http://www.w3.org/2003/01/geo/wgs84_pos#Point> ;
                <http://www.w3.org/2003/01/geo/wgs84_pos#lat>
                        "40.836695" ;
                <http://www.w3.org/2003/01/geo/wgs84_pos#long>
                        "-72.916725" ;
                <nex:rnode> <http://shield.ebremer.com/resources/0d0579a8-c217-4b3f-a0ed-734870eb5ede> ;
                <nex:vnode> <http://shield.ebremer.com/resources/0d0579a8-c217-4b3f-a0ed-734870eb5ede>
              ] ;
      <http://xmlns.com/foaf/0.1/birthday>
              "1968-04-22" ;
      <http://xmlns.com/foaf/0.1/family_name>
              "Bremer" ;
      <http://xmlns.com/foaf/0.1/firstName>
              "Erich" ;
      <http://xmlns.com/foaf/0.1/givenname>
              "Erich" ;
      <http://xmlns.com/foaf/0.1/holdsAccount>
              [ a       <http://xmlns.com/foaf/0.1/OnlineAccount> ;
                <http://xmlns.com/foaf/0.1/accountName>
                        "erich.bremer" ;
                <http://xmlns.com/foaf/0.1/accountServiceHomepage>
                        <http://www.skype.com/> ;
                <nex:rnode> <http://shield.ebremer.com/resources/68fb1356-03c3-4cc1-9bb0-7d8ac852fd55> ;
                <nex:vnode> <http://shield.ebremer.com/resources/68fb1356-03c3-4cc1-9bb0-7d8ac852fd55>
              ] ;
      <http://xmlns.com/foaf/0.1/homepage>
              <http://www.ebremer.com> ;
      <http://xmlns.com/foaf/0.1/img>
              <http://www.ebremer.com/ebfiles/erich.jpg> ;
      <http://xmlns.com/foaf/0.1/knows>
              [ a       <http://xmlns.com/foaf/0.1/Person> ;
                <http://www.w3.org/2000/01/rdf-schema#seeAlso>
                        <http://tdiprima.com/foaf.rdf#me> ;
                <http://xmlns.com/foaf/0.1/mbox>
                        <mailto:tammy.diprima@stonybrook.edu> ;
                <http://xmlns.com/foaf/0.1/name>
                        "Tammy DiPrima" ;
                <nex:rnode> <http://shield.ebremer.com/resources/c35ce390-4f59-4f99-9cec-fa3b041d5614> ;
                <nex:vnode> <http://shield.ebremer.com/resources/c35ce390-4f59-4f99-9cec-fa3b041d5614>
              ] ;
      <http://xmlns.com/foaf/0.1/mbox>
              <mailto:erich@ebremer.com> ;
      <http://xmlns.com/foaf/0.1/name>
              "Erich Bremer" ;
      <http://xmlns.com/foaf/0.1/phone>
              <tel:631-444-3560> ;
      <http://xmlns.com/foaf/0.1/schoolHomepage>
              <http://www.rpi.edu> ;
      <http://xmlns.com/foaf/0.1/status>
              "Happy" ;
      <http://xmlns.com/foaf/0.1/title>
              "Mr." ;
      <nex:rnode> <http://shield.ebremer.com/resources/d7b6d0c8-b610-4146-8e2b-6ea31ac1eb91> ;
      <nex:vnode> <http://shield.ebremer.com/resources/d7b6d0c8-b610-4146-8e2b-6ea31ac1eb91> .

<http://shield.ebremer.com/resources/9eeb0614-e1ed-4603-96e7-587ddaba32ca>
      a       <nex:cube> ;
      <nex:HoverText> "Happy" ;
      <nex:xyz> "-5.6631656,-1.3325166,-4.3307486" .

<http://shield.ebremer.com/resources/71fb6b92-4ea0-48e3-a2a7-48ec9275069d>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/homepage" ;
      <nex:objxyz> "6.8995605,-8.502952,-0.75715226" ;
      <nex:plen> "8.429293" ;
      <nex:rotation> "0.9126099 0.0 0.054065812 -0.40524074" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "4.093813,-5.385574,-0.34124255" .

<http://shield.ebremer.com/nex/graphs/22b1e8a2-eaac-4ce6-b62b-4901500e6748>
      <nex:lnode> <http://shield.ebremer.com/resources/c7954db7-d627-4cc3-9c3c-38dc35e18d51> ;
      <nex:pnode> <http://shield.ebremer.com/resources/60fd2aea-37a7-4dbf-bbc2-c78cf60df689> ;
      <nex:vnode> <http://shield.ebremer.com/resources/60fd2aea-37a7-4dbf-bbc2-c78cf60df689> , <http://shield.ebremer.com/resources/c7954db7-d627-4cc3-9c3c-38dc35e18d51> .

<http://shield.ebremer.com/resources/98cfdf87-8afa-438d-aeeb-715349442223>
      a       <nex:sphere> ;
      <nex:HoverText> "http://shield.ebremer.com/sessions/5d24b75c-7325-4122-9cf3-cf9c8708a534" ;
      <nex:nodesize> "4" ;
      <nex:numlinks> "4" ;
      <nex:q> "4" ;
      <nex:xyz> "18.789173,-6.010832,4.313797" .

<http://shield.ebremer.com/resources/af0c590e-779f-4743-b2fb-dbdf510b33ce>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/ns/auth/cert#key" ;
      <nex:objxyz> "1.9194171,-20.529259,3.117803" ;
      <nex:plen> "18.523653" ;
      <nex:rotation> "0.7190561 0.0 -0.114235714 -0.6854987" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "1.6037414,-11.398727,1.5962352" .

<http://shield.ebremer.com/nex/graphs/f1a77278-fe74-4f7a-a9f7-369ca786d3f2>
      <nex:lnode> <http://shield.ebremer.com/resources/ce47d7b7-02d2-491a-8a80-3fc723c21fa7> ;
      <nex:pnode> <http://shield.ebremer.com/resources/b2adefe1-d185-48bd-ad43-12d36ae6812e> ;
      <nex:vnode> <http://shield.ebremer.com/resources/b2adefe1-d185-48bd-ad43-12d36ae6812e> , <http://shield.ebremer.com/resources/ce47d7b7-02d2-491a-8a80-3fc723c21fa7> .

<http://shield.ebremer.com/nex/graphs/80e35282-6932-4a43-89a8-ace539ce016d>
      <nex:pnode> <http://shield.ebremer.com/resources/b4c745b0-a99a-4844-9437-396b719f1a4d> ;
      <nex:vnode> <http://shield.ebremer.com/resources/b4c745b0-a99a-4844-9437-396b719f1a4d> .

<http://shield.ebremer.com/resources/bb45dfba-9062-496e-9035-e8d4e9454ee4>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.daml.org/2001/10/html/airport-ont#elevation" ;
      <nex:objxyz> "-13.684594,19.697659,-7.6601453" ;
      <nex:plen> "7.0888653" ;
      <nex:rotation> "0.7655516 -0.0 0.6273029 0.14290461" ;
      <nex:subjxyz> "-14.904862,18.146603,-0.8515341" ;
      <nex:xyz> "-14.294728,18.92213,-4.25584" .

<http://shield.ebremer.com/resources/0d0579a8-c217-4b3f-a0ed-734870eb5ede>
      a       <nex:sphere> ;
      <nex:nodesize> "3" ;
      <nex:numlinks> "3" ;
      <nex:q> "3" ;
      <nex:xyz> "2.134508,-1.0674458,18.377794" .

<http://shield.ebremer.com/nex/graphs/bdb06cd0-ffd2-4dbe-9a9e-f64865d27a32>
      <nex:lnode> <http://shield.ebremer.com/resources/9eeb0614-e1ed-4603-96e7-587ddaba32ca> ;
      <nex:pnode> <http://shield.ebremer.com/resources/abe1d3d6-51ba-4060-a412-763d92ef4c06> ;
      <nex:vnode> <http://shield.ebremer.com/resources/abe1d3d6-51ba-4060-a412-763d92ef4c06> , <http://shield.ebremer.com/resources/9eeb0614-e1ed-4603-96e7-587ddaba32ca> .

<http://shield.ebremer.com/resources/007e136b-e05a-4061-b70e-1db5127a42b2>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.daml.org/2001/10/html/airport-ont#latitude" ;
      <nex:objxyz> "-20.15058,16.152966,3.8811495" ;
      <nex:plen> "7.34101" ;
      <nex:rotation> "0.37777174 0.0 -0.85328114 -0.35944363" ;
      <nex:subjxyz> "-14.904862,18.146603,-0.8515341" ;
      <nex:xyz> "-17.527721,17.149784,1.5148077" .

<http://shield.ebremer.com/resources/b3adf0db-7020-4ef7-b279-9b5188171c26>
      a       <nex:sphere> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/PersonalProfileDocument" ;
      <nex:xyz> "-14.76252,-9.281522,0.552921" .

<http://shield.ebremer.com/resources/051b6934-d1d3-493a-b8b7-6d6547204aa6>
      a       <nex:cube> ;
      <nex:HoverText> "-72.916725" ;
      <nex:xyz> "6.546685,1.1909465,23.601688" .

<http://shield.ebremer.com/resources/dff7e450-4434-48cf-9719-0144563cfe03>
      a       <nex:cube> ;
      <nex:HoverText> "40.836695" ;
      <nex:xyz> "1.8440512,-5.244094,24.264164" .

<http://shield.ebremer.com/resources/4e386d68-59b4-40a4-b2b1-172ce8ea572f>
      a       <nex:sphere> ;
      <nex:HoverText> "tel:631-444-3560" ;
      <nex:xyz> "0.61919737,2.2530727,-6.9366236" .

<http://shield.ebremer.com/resources/69d0c361-57e6-4ea2-b353-c14a12de84e1>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/givenname" ;
      <nex:objxyz> "3.5382593,4.096192,6.0742407" ;
      <nex:plen> "9.031261" ;
      <nex:rotation> "0.7903025 0.0 -0.42028958 0.445846" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "2.4131625,0.9139979,3.0744538" .

<http://shield.ebremer.com/resources/6eaa9557-cb96-49d0-ab66-18c57c097404>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/mbox" ;
      <nex:objxyz> "-2.7040677,-15.5965185,-18.37289" ;
      <nex:plen> "7.5463986" ;
      <nex:rotation> "0.64175904 0.0 0.36307096 -0.6755181" ;
      <nex:subjxyz> "-1.3737096,-9.053491,-14.856207" ;
      <nex:xyz> "-2.0388887,-12.325005,-16.614548" .

<http://www.ebremer.com/foaf.rdf>
      a       <http://xmlns.com/foaf/0.1/PersonalProfileDocument> ;
      <http://xmlns.com/foaf/0.1/maker>
              <http://www.ebremer.com/foaf.rdf#me> ;
      <http://xmlns.com/foaf/0.1/primaryTopic>
              <http://www.ebremer.com/foaf.rdf#me> ;
      <http://xmlns.com/foaf/0.1/title>
              "Erich Bremer's profile" ;
      <nex:rnode> <http://shield.ebremer.com/resources/b41b960d-45dc-42b9-9140-6a8c494dfe50> ;
      <nex:vnode> <http://shield.ebremer.com/resources/b41b960d-45dc-42b9-9140-6a8c494dfe50> .

<http://shield.ebremer.com/nex/graphs/9d6ac1b0-6f2f-47c0-ae34-a500e7700bbf>
      <nex:lnode> <http://shield.ebremer.com/resources/c5a8ee68-26e2-4f8e-af3a-239042d5cf27> ;
      <nex:pnode> <http://shield.ebremer.com/resources/bb08e58a-655b-4920-b5ee-1588914ae382> ;
      <nex:vnode> <http://shield.ebremer.com/resources/c5a8ee68-26e2-4f8e-af3a-239042d5cf27> , <http://shield.ebremer.com/resources/bb08e58a-655b-4920-b5ee-1588914ae382> .

<http://shield.ebremer.com/resources/7513d558-1ab3-4705-ae5f-7ee586ec4b0b>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/based_near" ;
      <nex:objxyz> "2.134508,-1.0674458,18.377794" ;
      <nex:plen> "18.361992" ;
      <nex:rotation> "0.72322106 0.0 -0.68913525 0.04520973" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "1.7112868,-1.6678209,9.226231" .

<http://shield.ebremer.com/resources/35f94abd-847a-490a-86eb-22f2e3726060>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.daml.org/2001/10/html/airport-ont#location" ;
      <nex:objxyz> "-18.284475,24.98204,3.2179208" ;
      <nex:plen> "8.643232" ;
      <nex:rotation> "0.55180943 0.0 -0.42661977 0.7165905" ;
      <nex:subjxyz> "-14.904862,18.146603,-0.8515341" ;
      <nex:xyz> "-16.59467,21.564322,1.1831933" .

<http://shield.ebremer.com/resources/027fd95a-b962-4f27-8634-a61fd7f3741d>
      a       <nex:cube> ;
      <nex:HoverText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http://www.w3.org/2001/XMLSchema#hexBinary> ;
      <nex:xyz> "5.035039,-26.519365,0.5492316" .

<http://www.ebremer.com>
      <nex:rnode> <http://shield.ebremer.com/resources/666541e3-5ed4-4ee1-87eb-3fc170af8b59> ;
      <nex:vnode> <http://shield.ebremer.com/resources/666541e3-5ed4-4ee1-87eb-3fc170af8b59> .

<http://shield.ebremer.com/resources/db23a1f7-83eb-4402-8bbd-28a477393d88>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/ns/auth/cert#exponent" ;
      <nex:objxyz> "-2.369653,-26.378757,3.3365998" ;
      <nex:plen> "7.2567644" ;
      <nex:rotation> "0.4521922 0.0 -0.033338398 -0.8912972" ;
      <nex:subjxyz> "1.9194171,-20.529259,3.117803" ;
      <nex:xyz> "-0.22511792,-23.454008,3.2272015" .

<http://shield.ebremer.com/resources/a6e56026-c5bd-4331-ab7a-20b0f1c8660a>
      a       <nex:sphere> ;
      <nex:HoverText> "http://www.w3.org/ns/auth/cert#RSAPublicKey" ;
      <nex:xyz> "3.6347718,-25.323143,8.237062" .

<http://shield.ebremer.com/nex/graphs/bb1f51ac-d0e5-4e17-8948-6e8b7cf9ba38>
      <nex:pnode> <http://shield.ebremer.com/resources/a1e381fd-5527-4cba-a92c-9174792ca6a2> ;
      <nex:vnode> <http://shield.ebremer.com/resources/a1e381fd-5527-4cba-a92c-9174792ca6a2> .

<http://shield.ebremer.com/nex/graphs/53f44285-1ec2-4a25-a65a-edb37287ddc5>
      <nex:lnode> <http://shield.ebremer.com/resources/9a016505-55fc-40e1-bbe0-5895319289be> ;
      <nex:pnode> <http://shield.ebremer.com/resources/583634b9-1410-4e35-8bbc-40a12317ac72> ;
      <nex:vnode> <http://shield.ebremer.com/resources/9a016505-55fc-40e1-bbe0-5895319289be> , <http://shield.ebremer.com/resources/583634b9-1410-4e35-8bbc-40a12317ac72> .

<http://shield.ebremer.com/resources/68fb1356-03c3-4cc1-9bb0-7d8ac852fd55>
      a       <nex:sphere> ;
      <nex:nodesize> "3" ;
      <nex:numlinks> "3" ;
      <nex:q> "3" ;
      <nex:xyz> "12.902582,7.535981,-10.111939" .

<http://shield.ebremer.com/resources/322e2c62-2466-4250-82d0-95bd38dea1f8>
      a       <nex:sphere> ;
      <nex:HoverText> "http://www.skype.com/" ;
      <nex:xyz> "13.079804,11.690309,-15.968671" .

<http://shield.ebremer.com/resources/8762b36d-8dec-4a91-9f68-869a1a5db36f>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/name" ;
      <nex:objxyz> "1.7432859,-10.034435,-21.6401" ;
      <nex:plen> "7.529882" ;
      <nex:rotation> "0.84081805 0.0 0.5357458 -0.07746834" ;
      <nex:subjxyz> "-1.3737096,-9.053491,-14.856207" ;
      <nex:xyz> "0.18478817,-9.5439625,-18.248154" .

<http://shield.ebremer.com/nex/graphs/59170156-1382-4874-bd1c-92fd9d9e1274>
      <nex:pnode> <http://shield.ebremer.com/resources/71fb6b92-4ea0-48e3-a2a7-48ec9275069d> ;
      <nex:vnode> <http://shield.ebremer.com/resources/71fb6b92-4ea0-48e3-a2a7-48ec9275069d> .

<http://shield.ebremer.com/nex/graphs/eb5cf9d4-b962-4a40-88e0-9792b9ce0631>
      <nex:lnode> <http://shield.ebremer.com/resources/dff7e450-4434-48cf-9719-0144563cfe03> ;
      <nex:pnode> <http://shield.ebremer.com/resources/f9ba89b7-fe3d-43a8-bc80-018e0b18e8a2> ;
      <nex:vnode> <http://shield.ebremer.com/resources/f9ba89b7-fe3d-43a8-bc80-018e0b18e8a2> , <http://shield.ebremer.com/resources/dff7e450-4434-48cf-9719-0144563cfe03> .

<http://shield.ebremer.com/resources/8f667cb6-ba11-4f04-95fb-6f8de631b750>
      a       <nex:cube> ;
      <nex:HoverText> "68.195.227.26" ;
      <nex:xyz> "22.810303,-9.893983,8.884933" .

<http://shield.ebremer.com/nex/graphs/183bf392-422e-4f79-80c4-73a80d8bfefd>
      <nex:lnode> <http://shield.ebremer.com/resources/7a62ac94-793e-4bba-8a72-6cfae00b86b1> ;
      <nex:pnode> <http://shield.ebremer.com/resources/05b2d050-0b51-4230-9056-ec14340663a2> ;
      <nex:vnode> <http://shield.ebremer.com/resources/7a62ac94-793e-4bba-8a72-6cfae00b86b1> , <http://shield.ebremer.com/resources/05b2d050-0b51-4230-9056-ec14340663a2> .

<mailto:erich@ebremer.com>
      <nex:rnode> <http://shield.ebremer.com/resources/8fe9f157-afdc-45fe-a669-c2f51de7e7a5> ;
      <nex:vnode> <http://shield.ebremer.com/resources/8fe9f157-afdc-45fe-a669-c2f51de7e7a5> .

<http://shield.ebremer.com/resources/58ec8462-762e-4982-a46e-6737b8254dfb>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/firstName" ;
      <nex:objxyz> "6.9691315,-3.1183655,-5.7980638" ;
      <nex:plen> "8.215002" ;
      <nex:rotation> "0.9196596 0.0 0.38866487 -0.05626531" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "4.1285987,-2.6932807,-2.8616984" .

<http://shield.ebremer.com/resources/9e449a77-55e3-4aab-a281-225071956f18>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/1999/02/22-rdf-syntax-ns#type" ;
      <nex:objxyz> "24.798235,-2.705969,6.5723734" ;
      <nex:plen> "7.220257" ;
      <nex:rotation> "0.95714426 0.0 -0.16340853 0.23910758" ;
      <nex:subjxyz> "18.789173,-6.010832,4.313797" ;
      <nex:xyz> "21.793705,-4.3584003,5.443085" .

<tel:631-444-3560>
      <nex:rnode> <http://shield.ebremer.com/resources/4e386d68-59b4-40a4-b2b1-172ce8ea572f> ;
      <nex:vnode> <http://shield.ebremer.com/resources/4e386d68-59b4-40a4-b2b1-172ce8ea572f> .

<http://shield.ebremer.com/resources/0a277f4a-241d-437d-8a28-84cae8d9cbde>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/name" ;
      <nex:objxyz> "6.757046,-3.423891,6.078216" ;
      <nex:plen> "8.202926" ;
      <nex:rotation> "0.9128831 0.0 -0.40086132 -0.07716658" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "4.022556,-2.8460436,3.0764415" .

<nex:clientsession>
      <nex:rnode> <http://shield.ebremer.com/resources/170959a5-3e99-4dc9-9fbd-e94c2e55b419> ;
      <nex:vnode> <http://shield.ebremer.com/resources/170959a5-3e99-4dc9-9fbd-e94c2e55b419> .

<http://shield.ebremer.com/nex/graphs/86fc0ea3-742a-44c6-9e72-7176b2410f74>
      <nex:lnode> <http://shield.ebremer.com/resources/8f667cb6-ba11-4f04-95fb-6f8de631b750> ;
      <nex:pnode> <http://shield.ebremer.com/resources/8d846a2a-1bb0-4a85-bbbd-941caba6cce4> ;
      <nex:vnode> <http://shield.ebremer.com/resources/8d846a2a-1bb0-4a85-bbbd-941caba6cce4> , <http://shield.ebremer.com/resources/8f667cb6-ba11-4f04-95fb-6f8de631b750> .

<http://shield.ebremer.com/nex/graphs/15b7f9b2-58b8-43e4-95ba-a76b2b4ccfb2>
      <nex:pnode> <http://shield.ebremer.com/resources/af0c590e-779f-4743-b2fb-dbdf510b33ce> ;
      <nex:vnode> <http://shield.ebremer.com/resources/af0c590e-779f-4743-b2fb-dbdf510b33ce> .

<http://shield.ebremer.com/nex/graphs/ae649e36-e6f7-477c-80c2-7e1c4b4a24e9>
      <nex:lnode> <http://shield.ebremer.com/resources/29bb010a-ac87-4b82-9171-c7c2b81793f8> ;
      <nex:pnode> <http://shield.ebremer.com/resources/0a277f4a-241d-437d-8a28-84cae8d9cbde> ;
      <nex:vnode> <http://shield.ebremer.com/resources/29bb010a-ac87-4b82-9171-c7c2b81793f8> , <http://shield.ebremer.com/resources/0a277f4a-241d-437d-8a28-84cae8d9cbde> .

<http://shield.ebremer.com/resources/c0438c52-0da4-46db-953e-c3d4d5224d5a>
      a       <nex:cube> ;
      <nex:HoverText> "Tammy DiPrima" ;
      <nex:xyz> "1.7432859,-10.034435,-21.6401" .

<http://shield.ebremer.com/nex/graphs/bef64ed1-e056-4889-a1fe-9079eb88b6b6>
      <nex:lnode> <http://shield.ebremer.com/resources/c0438c52-0da4-46db-953e-c3d4d5224d5a> ;
      <nex:pnode> <http://shield.ebremer.com/resources/8762b36d-8dec-4a91-9f68-869a1a5db36f> ;
      <nex:vnode> <http://shield.ebremer.com/resources/c0438c52-0da4-46db-953e-c3d4d5224d5a> , <http://shield.ebremer.com/resources/8762b36d-8dec-4a91-9f68-869a1a5db36f> .

<http://shield.ebremer.com/nex/graphs/a3e64c9f-e7ca-4c50-8692-489a60b02d59>
      <nex:pnode> <http://shield.ebremer.com/resources/7513d558-1ab3-4705-ae5f-7ee586ec4b0b> ;
      <nex:vnode> <http://shield.ebremer.com/resources/7513d558-1ab3-4705-ae5f-7ee586ec4b0b> .

<http://shield.ebremer.com/nex/graphs/cd2f3763-96c8-458a-81d9-4797a29d3de8>
      <nex:pnode> <http://shield.ebremer.com/resources/bcc8f0a5-e903-4fc2-83e5-3b3d2b774669> ;
      <nex:vnode> <http://shield.ebremer.com/resources/bcc8f0a5-e903-4fc2-83e5-3b3d2b774669> .

<http://shield.ebremer.com/resources/05b2d050-0b51-4230-9056-ec14340663a2>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.daml.org/2001/10/html/airport-ont#icaoCode" ;
      <nex:objxyz> "-19.809538,15.09504,-5.055586" ;
      <nex:plen> "7.1443634" ;
      <nex:rotation> "0.3959104 0.0 0.7431519 -0.53942585" ;
      <nex:subjxyz> "-14.904862,18.146603,-0.8515341" ;
      <nex:xyz> "-17.3572,16.620821,-2.9535599" .

<http://shield.ebremer.com/resources/666541e3-5ed4-4ee1-87eb-3fc170af8b59>
      a       <nex:sphere> ;
      <nex:HoverText> "http://www.ebremer.com" ;
      <nex:xyz> "6.8995605,-8.502952,-0.75715226" .

<http://shield.ebremer.com/resources/170959a5-3e99-4dc9-9fbd-e94c2e55b419>
      a       <nex:sphere> ;
      <nex:HoverText> "nex:clientsession" ;
      <nex:xyz> "24.798235,-2.705969,6.5723734" .

<http://shield.ebremer.com/nex/graphs/d8f859e7-3a2c-49c5-8ae3-0e977fa10d20>
      <nex:pnode> <http://shield.ebremer.com/resources/fb33cb18-d2b7-4cd6-ad1b-dd4545dfe5ef> ;
      <nex:vnode> <http://shield.ebremer.com/resources/fb33cb18-d2b7-4cd6-ad1b-dd4545dfe5ef> .

<http://shield.ebremer.com/resources/c80a1c26-be88-4859-a97b-155acb835e1f>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/2000/01/rdf-schema#seeAlso" ;
      <nex:objxyz> "-6.128773,-8.901025,-20.684343" ;
      <nex:plen> "7.523367" ;
      <nex:rotation> "0.42892927 -0.0 0.90302914 0.023623515" ;
      <nex:subjxyz> "-1.3737096,-9.053491,-14.856207" ;
      <nex:xyz> "-3.7512414,-8.977258,-17.770275" .

<http://shield.ebremer.com/resources/b4c745b0-a99a-4844-9437-396b719f1a4d>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/holdsAccount" ;
      <nex:objxyz> "12.902582,7.535981,-10.111939" ;
      <nex:plen> "18.297153" ;
      <nex:rotation> "0.904094 -0.0 0.30789486 0.29633576" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "7.095324,2.6338925,-5.018636" .

<http://shield.ebremer.com/resources/d7b6d0c8-b610-4146-8e2b-6ea31ac1eb91>
      a       <nex:sphere> ;
      <nex:HoverText> "http://www.ebremer.com/foaf.rdf#me" ;
      <nex:nodesize> "18" ;
      <nex:numlinks> "18" ;
      <nex:q> "18" ;
      <nex:xyz> "1.2880657,-2.268196,0.074667156" .

<http://shield.ebremer.com/resources/b703c2aa-c634-46b0-85e6-96cb3c94d34b>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/phone" ;
      <nex:objxyz> "0.61919737,2.2530727,-6.9366236" ;
      <nex:plen> "8.369435" ;
      <nex:rotation> "0.67826325 -0.0 0.617552 0.39823174" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "0.9536315,-0.0075616837,-3.4309783" .

<http://shield.ebremer.com/resources/b41b960d-45dc-42b9-9140-6a8c494dfe50>
      a       <nex:sphere> ;
      <nex:HoverText> "http://www.ebremer.com/foaf.rdf" ;
      <nex:nodesize> "4" ;
      <nex:numlinks> "4" ;
      <nex:q> "4" ;
      <nex:xyz> "-7.744496,-6.2348194,2.3804553" .

<http://shield.ebremer.com/resources/5997861f-a88d-479d-8e2a-52a701c49cb1>
      a       <nex:cube> ;
      <nex:HoverText> "1360634398601" ;
      <nex:xyz> "24.7447,-8.840323,1.3769542" .

<http://shield.ebremer.com/resources/4adc5dcd-ddf4-4592-9e54-0c0686dd8f9b>
      a       <nex:cube> ;
      <nex:HoverText> "Mr." ;
      <nex:xyz> "8.727002,1.4348108,0.31527075" .

<http://shield.ebremer.com/resources/a6ff1888-c243-4126-acbf-b44c651855b0>
      a       <nex:sphere> ;
      <nex:HoverText> "mailto:tammy.diprima@stonybrook.edu" ;
      <nex:xyz> "-2.7040677,-15.5965185,-18.37289" .

<http://shield.ebremer.com/resources/d2ce17d5-c4cd-434f-8c78-7fe5e9b79fff>
      a       <nex:cube> ;
      <nex:HoverText> "-73.097545" ;
      <nex:xyz> "-23.10833,20.7913,-1.7015207" .

<http://shield.ebremer.com/resources/b923152a-8efc-4ff2-9dba-1d1abdedab44>
      a       <nex:cube> ;
      <nex:HoverText> "Islip, New York, United States" ;
      <nex:xyz> "-18.284475,24.98204,3.2179208" .

<http://shield.ebremer.com/resources/a59dd00a-e501-4c76-ac18-de0141a3f0d4>
      a       <nex:sphere> ;
      <nex:HoverText> "http://www.rpi.edu" ;
      <nex:xyz> "-2.4844422,-1.1644895,7.222489" .

<http://shield.ebremer.com/resources/abe1d3d6-51ba-4060-a412-763d92ef4c06>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://xmlns.com/foaf/0.1/status" ;
      <nex:objxyz> "-5.6631656,-1.3325166,-4.3307486" ;
      <nex:plen> "8.2826805" ;
      <nex:rotation> "0.28350577 -0.0 0.93804586 0.19923441" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "-2.18755,-1.8003564,-2.1280408" .

<http://shield.ebremer.com/resources/fe02cb3e-5e78-4345-8ffd-dc664eb00162>
      a       <nex:sphere> ;
      <nex:HoverText> "http://www.w3.org/2003/01/geo/wgs84_pos#Point" ;
      <nex:xyz> "-1.2423172,1.9353592,23.958439" .

<http://shield.ebremer.com/resources/feb37eec-a3b8-48ba-9bd1-780baa0923c5>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.daml.org/2001/10/html/airport-ont#name" ;
      <nex:objxyz> "-17.589022,25.33923,-4.8700905" ;
      <nex:plen> "8.6652975" ;
      <nex:rotation> "0.5874693 -0.0 0.3947039 0.7064621" ;
      <nex:subjxyz> "-14.904862,18.146603,-0.8515341" ;
      <nex:xyz> "-16.246943,21.742916,-2.8608122" .

<http://shield.ebremer.com/resources/8eff4274-4595-4556-8b5c-b56309bd0d8c>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/1999/02/22-rdf-syntax-ns#type" ;
      <nex:objxyz> "-0.31521404,-6.5853963,-9.528153" ;
      <nex:plen> "10.650018" ;
      <nex:rotation> "0.6517121 0.0 0.69177145 -0.311004" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "0.48642582,-4.426796,-4.726743" .

<http://shield.ebremer.com/resources/b6ecaf9e-d9fe-44f8-bd45-9188fec00d0b>
      a       <nex:sphere> ;
      <nex:nodesize> "8" ;
      <nex:numlinks> "8" ;
      <nex:q> "8" ;
      <nex:xyz> "-14.904862,18.146603,-0.8515341" .

<http://shield.ebremer.com/nex/graphs/d9971994-d4f1-40c5-acce-b2ddf093a59f>
      <nex:pnode> <http://shield.ebremer.com/resources/bd6d61f7-32cf-41c3-97ce-d10e88baba18> ;
      <nex:vnode> <http://shield.ebremer.com/resources/bd6d61f7-32cf-41c3-97ce-d10e88baba18> .

<http://shield.ebremer.com/resources/e2ac006c-0dfe-42d8-b140-9941afc549c8>
      a       <nex:sphere> ;
      <nex:HoverText> "http://www.ebremer.com/ebfiles/erich.jpg" ;
      <nex:xyz> "0.9335052,-8.212778,5.893996" .

<http://shield.ebremer.com/resources/6b9c8582-487c-42d9-8298-e9cc51762d2f>
      a       <nex:cylinder> ;
      <nex:HoverText> "http://www.w3.org/2000/10/swap/pim/contact#nearestAirport" ;
      <nex:objxyz> "-14.904862,18.146603,-0.8515341" ;
      <nex:plen> "26.073603" ;
      <nex:rotation> "0.43528903 -0.0 0.040803414 0.8993656" ;
      <nex:subjxyz> "1.2880657,-2.268196,0.074667156" ;
      <nex:xyz> "-6.8083982,7.9392033,-0.3884335" .

<http://shield.ebremer.com/resources/92f18885-f7cb-4b4b-8e64-ae07ba8e127c>
      a       <nex:cube> ;
      <nex:HoverText> "Erich" ;
      <nex:xyz> "3.5382593,4.096192,6.0742407" .

Tags: 

Nexus Project: WebGL Client/Server Communications Test using RDF over WebSockets

Submitted by ebremer on

 A video from a July 25, 2011 showing the first successful test run of my Nexus Project's WebGL client/server communications using HTML5 WebSockets rather than http polling.  This visualization shows Friend of a Friend (FOAF) RDF graph data being displayed in 3D as it's layout is being determined by a 3D force-directed layout algorithm.  I got tired of digging up the video on my iPhone to show people so I decided to post it.  There have been many things done since this video (latest browser support, Jetty 8, GLGE 0.9, speed improvements, and better screen capture than my iPhone too ;-)  I have been considering a different RDF serialization rather than N-TRIPLES since N-TRIPLES since it is hopelessly uncompressed, but it made for the easiest implementation since N-TRIPLE parsers are easy to write in javascript.  Jena also supports N-TRIPLES serialization so nothing had to be done on the server end of things.  I was just at the ISWC 2012 in Boston and it was suggested to me to use Turtle RDF (I was also considering JSON-LD or even the binary RDF format), but honestly, the speed of N-TRIPLES is sufficient for now and I would rather work towards a first release of the software.  It's too aluring to endlessly tinker (and I love to tinker by the way).

Tags: 

Nexus Upgraded from Jetty 7 to Jetty 8 now supporting WebSocket RFC6455

Submitted by ebremer on

Nexus has been upgraded from Jetty 7 to the latest Jetty 8 which supports the RFC 6455 version of the WebSocket protocol.  This allows the use of the latest FireFox 13 and Google Chrome browsers and, of course, all of the improvements to both browsers, especially the HTML5 and WebGL support.  I've been holding back on updating because of the number of revisions the WebSocket protocol has been going through.  I wanted to spend my time on core Nexus development rather than just bumping the WebSocket revision support up a notch.  Fortunately, the revisions needed to the Jetty parts of the Nexus code were easy.  Thank you Jetty team!  An added benefit to the code update was the removal of a non thread-safe queue I was using which was causing intermittent crashes when using multiple clients on the Nexus server.

Tags: 

Building HTML5 pages one RDF Triple at a Time

Submitted by ebremer on

Alright, it doesn't look like much, but there is something special about the web dialog that is being displayed over the 3D graph - it was built triple by triple.  I had reached the point in developing Nexus where I needed to have interactive dialogs for display control and user-input.  Up until this point, I had been working with 3D objects and taking SPARQL commands via a text box at the bottom of the screen, but easier control over visualizations was needed.  Nexus client/server communications works by passing the RDF data that represents the 3D visual displays to the client from the server as RDF over the HTML5 WebSockets protocol with the client sending back any responses to the server back over the same bi-directional WebSockets connection.

But how to handle HTML5 web dialogs?  Also, in keeping with one of the Nexus design principals "it must be collaborative", how would I keep HTML5 dialogs synchronized between multiple clients?  Another Nexus design principal is "it must be RDF".  If you think about it, HTML, CSS, SVG, and RDF are all just data in the end, but four different styles of data formats.  If we have RDF, why not just make them all RDF?  I had looked around and people had asked the question of how to represent actual HTML pages as RDF years ago, but they only comprehensive work I could find on the subject, is TopQuadrant's SPARQL Web Pages. (http://uispin.org/).  TopQuadrant represents SPARQL (as SPIN - SPARQL as RDF) and HTML/CSS as RDF and then processes the combination of RDF data server-side to render HTML pages (in the same fashion as JSP, ASP, PHP) and then passes the rendered HTML/CSS pages to the client.  TopQuadrant even has RDF ontologies to represent HTML 4.01, CSS, and SVG Tiny1.2.

But, I wanted to put a slightly different "spin" on this.  ;-)  I decided I wanted to take the web pages represented as RDF on the server and then pass that data to the client as RDF over the WebSockets and then render the web pages (or fragments) triple-by-triple using the HTML Document Object Model (DOM) client-side.  I created my own HTML/CSS ontologies since TopQuadrant's is weighted towards their SPIN technology.  The above image is a 3D depiction of Tim Berner-Lee's FOAF file as a 3D graph.  The black dialog was built by executing the following SPARQL query against the graph to determine the number of each type of predicate used in the RDF graph.  This is a precursor dialog to allow a user to remove uninformative predicates from the view (for example removing triples that represent gender when you know you are looking at a same-sex population of people).

SPARQL Query to determine numbers of different predicates:
select distinct ?p (count(?p) as ?count)
where {graph ?g {?s ?p ?o}}
group by ?p
order by desc(?count)

After the execution of this SPARQL query, I follow the same model as I do in the 3D visualizations.  You never see your actual data, you see something that is a visual representation of your data.  By having this visualization layer over the actual data, it allows for multiple visualizations of the same thing at the same time.  It also allows for an amazing level of flexibility since visual data can be manipulated by a variety of SPARQL update queries against a combination of the visual data and the actual data (both being represented as RDF). The results are wrapped in HTML/CSS (an RDF version of it) which then creates the final RDF graph which can be viewed in this link (HTML/CSS as RDF).  This is the actual data that is sent over the WebSockets connection to build the dialog.  The client then reads the data triple by triple and then creates the HTML fragment (wrapped in a DIV) and then adds it to the existing web page.  Each row of the table in RDF has a <nex:clickable> set to true on it.  What is this for?  It tells the client to attach an onclick handler to the row.  All rows have a unique ID set.  The onclick handler simply sends a single triple back to the server to indicate which object (row) has been clicked.  For example:

<http://www.ebremer.com/nex/ses/7548c5d4-8ea8-40e8-8726-fa8819a62fe6> <html:event> <html:hasBeenClicked>

It is then up to the server to determine how to respond to the end-user's click.  For what I am working on, at the moment, is that the background color will be set to a "highlight" color which will take a single triple to the client to do.  Keep in mind that another client may be attached to this visualization at the same time and that same triple can also be sent to keep that client's version of the dialog in synch with the client who did the clicking.  There is also no reason why multiple clients cannot click on the same dialog at the same time and on different rows (but on different browsers) for everyone to pick what they want to select.  Singular triple changes allows for alot of flexibility, as well as, a "AJAX-like" experience since no screen refreshes are required on any of the concurrent clients.

Other updates since last blog post:

1) The force-directed layout engine as been re-written to take advantage of multiple cores.  This has greatly accelerated layout computations since I work on a 6-core computer most of the time.

2) The "classic" RDF reification model which allows Nexus to make statements about specific triple's literals and specific triple's predicates has been replaced with a Named Graph version of RDF reification.  The notation is much easier to work with than using rdf:Statement, rdf:subject, rdf:predicate, rdf:object styled reification.  This was done after the newer Apache Jena library was added to Nexus.

3) Creation of a threaded 3D visualization "controller" - the earlier version of Nexus worked SPARQL command by SPARQL command.  In the new version, it can process multiple triples in batches, as well as, run layouts in a separate thread(s) which also enables incremental updates to the current visualization.  Essentially, a user can watch a graph layout occur as it happens.  This has been very helpful in debugging since I can see live what is actually happening.

4) XY/XZ client rotations and zooming with the ablity to alt-click a new center of rotation to allow "camming" through the 3D simulations.  Fun with quaternions!  (http://en.wikipedia.org/wiki/Quaternion)

5) COLLADA duck avatar representation of different clients.  This is needed to let a client know where other clients are collaboratively "looking" in the 3D visualization.  The duck was less boring than a ball or a cube or an arrow. And it makes my kids laugh.  :-)

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Plain text icon tblhtmlpredicates.txt

RDF Triples over HTML5 WebSockets

Submitted by ebremer on

From the beginning, I wanted Nexus to be a collaborative visualization system allowing multiple clients in multiple locations to see the same visualizations in real-time.  The issue that arises here is knowing "where" in the 3D semantic web visualization the other clients (people/avatars) are and what direction they are looking at.  In the 3D digital world, you have the concept of a "camera".  This is essentially your point-of-view in a particular 3D simulation.  As the camera moves, your view of the model changes as well.  In order to know where the other clients are in the simulation, the camera position and rotation data on all clients are converted to RDF triples and then sent to the Nexus server to be resent and synchronized to all other clients.  Nexus eats, breathes, and internalizes everything as RDF.  HTTP polling would not work well as a transport for these triples, especially with a dozen or more clients all trying to sychronize with each other.  The solution is sending the RDF N-Triples using the HTML5 WebSocket protocol. 

What are WebSockets?  The WebSocket protocol is a bi-directional, full-duplex communications protocol that is part of the HTML5 specification.  WebSockets allow my WebGL clients to talk back and forth with the Nexus server without resorting to http polling.  I will be adding WebSockets to my OpenSimulator client as well.

I've embedded Jetty in Nexus so Apache Tomcat is no longer necessary to run Nexus which simplifies the deployment of the Nexus server software.  Jetty also has a nice clean HTML5 WebSockets implementation and allows me to do both http and WebSockets on the same ip and port.  Nexus client/server communications are all just streams of RDF triples going in both directions using the HTML5 WebSockets protocol.

Here is my poster for my 2011 Gordon Conference on Visualization in Science and Education that I did a couple weeks ago where I presented the progress so far on Nexus.

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PDF icon gordon-conference-2011-poster.pdf

Nexus WebGL 3D RDF client in Technicolor

Submitted by ebremer on

It took less time than I thought it would, but here is an updated version of the 3D FOAF graph from my last posting with node sizes determined by the log base 10 of the number of links into a particular node.  The coulombs law for the larger nodes is adjusted so that larger nodes "push" out harder to accomodate the larger spheres preventing sphere clashes.  This images was taken with the WebGL running in Chrome.

Next on the agenda for additional functionality is the actual display of text labels over subjects, predicates, and objects.  Also to be added is WebGL camera and avatar positioning data.  What's this?  In the Opensimulator client, dozens of people can view and interact with the same RDF model/structure.  Where one of those people are looking or focusing their attention is indicated by their 3D cursor or avatar.  However, this leaves the WebGL client users in the dark as to what the OpenSimulator users and/or other WebGL clients are doing in the simulation.  I am planning to synchronize this information between all of the clients by streaming the avatar (or camera position data in the case of WebGL) back to the Nexus server where it will be pushed out to all clients in the form of more RDF triples.

The SPARQL commands for the colors and such for this image are as follows:

1) Make everything blue
insert {?rnode <nex:color> "0,0,1"} where {?node <nex:rnode> ?rnode}
insert {?pnode <nex:color> "0,0,1"} where {?node <nex:pnode> ?pnode}

2) Color white all literals
insert {?lnode <nex:color> "1,1,1"} where {?node <nex:lnode> ?lnode}

3) Color red all triples that are of foaf:knows
modify delete {?rnode <nex:color> "0,0,1"} insert {?rnode <nex:color> "1,0,0"}  where {?node <nex:rnode> ?rnode . ?node foaf:knows ?o }
modify delete {?pnode <nex:color> "0,0,1"} insert {?pnode <nex:color> "1,0,0"}  where {?node <nex:pnode> ?pnode . ?node rdf:predicate foaf:knows }

4) color green all triples of type rdf:type
modify delete {?rnode <nex:color> "0,0,1"} insert {?rnode <nex:color> "0,1,0"}  where {?node <nex:rnode> ?rnode . ?node rdf:type ?o }
modify delete {?pnode <nex:color> "0,0,1"} insert {?pnode <nex:color> "0,1,0"}  where {?node <nex:pnode> ?pnode . ?node rdf:predicate rdf:type }

5) Make everything shiny
insert {?rnode <nex:shiny> "3"} where {?node <nex:rnode> ?rnode}
insert {?pnode <nex:shiny> "3"} where {?node <nex:pnode> ?pnode}
insert {?lnode <nex:shiny> "3"} where {?node <nex:lnode> ?lnode}

Yes, I am planning on coming up with a far easier interface for the user other than SPARQL. :-)

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3D RDF FOAF in WebGL-HTML5 linked to OpenSimulator

Submitted by ebremer on

The adjacent image is of Tim Berners-Lee's FOAF file imaged with a new HTML5 / WebGL client I am developing for my Nexus RDF visualization server. WebGL allows for sophisticated 3D graphics within a web browser with no plug-in required.  The visualization is in 3D with a layout determined by a force-directed algorithm driven by the Nexus server.  The below color image is also Tim Berners-Lee's FOAF file, imaged in the same fashion, but from within an OpenSimulator region.  The twist is that both images are created off of the same server session.  In other words, the session is occuring concurrently in the HTML5/WebGL client and the OpenSimulator region allowing multiple users in the OpenSimulator region to collaborate in real-time with multiple HTML5 / WebGL clients.

In the intial testing/debugging of the HTML5 / WebGL client, I was able to get 14-16 frames per second using FireFox 5 (beta).  Greater frame rates were achievable in testing with Chrome.

To speed the development of the HTML5 /WebGL client, I made use of Paul Brunt's GLGE WebGL library which is an amazing piece of work in itself.  Currently, N-triples over HTTP is used to communicate between the clients and the server, but WebSockets is being explored.

The OpenSimulator client avoids the use of the standard OpenSim object inventory for object handling by using an RDF store with dereferenceable URIs.

Hopefully, in the next couple of weeks I will have color and variable nodesizes debugged.

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SPARQL 1.1 Controlled 3D RDF Visualization - from a Force-Directed Layout to a Molecular Visualization of DNA using Nexus in OpenSimulator

Submitted by ebremer on

Nexus is an experiment with Semantic Web RDF data visualized in three dimensiodians that can be done collaboratively amongst many people (and concurrently) at disparate locations.  Nexus also acts as a platform to try out various design ideas, technologies, and methodologies.  The original Nexus design read and displayed RDF data and could also export it.  I have reworked the back-end of Nexus to use RDF internally and to communicate with its front-end client(s) in pure N-Triples.  The internal RDF representation enables the use of SPARQL (the query language for RDF) via Jena ARQ to manipulate the RDF graph and thus the over-all visualization.  In this posting, I will show the SPARQL 1.1 commands used to manipulate the structural data of a strand of DNA that has been converted to RDF from the original PDB format.  The resulting display will be shown as a force-directed layout and then manipulated into a physical RDF layout determined by crystal structure coordinates contained within the RDF.  Essentially, this will allow for molecular visualization within Nexus allowing us to actually see the strand of DNA in a physical form.

Basic Visualization Design Concepts in Nexus
The basic unit of information we want to visualize is the RDF triple:

Subject - Predicate - Object

In keeping with the "pure RDF" concept, this triple would be annotated with a RDF triples using a display ontology designed for Nexus, it's prefix being "nex".  Statements like nex:color, nex:xyz, nex:glow, nex:nodesize could be made about any resource whether it be subject or object.  For each resource, a "display node" triple is introduced and attached to the original rdf resource. RDF nex statements would then be made about that display node.  For example:

?s ?p ?o
?s nex:rnode ?displaynode
?displaynode nex:color "1,0,0" (red)
?displaynode nex:xyz "2.34,7.34,1.23"e
?displaynode rdf:type nex:sphere
?displaynode nex:radius "3.4"
    and so on.....

Adding this "display node" layer added a large degree of flexibility for RDF displays.  At one point, the display nodes were represented as blank nodes, but in the current version of Nexus, I converted these to resources.  It was just easier to work with in this way.

Fun with RDF Reification
Visualization nodes cannot be attached directly to predicates and literals because RDF statements cannot be made about predicates or literals.  You can only make RDF statements about resources.  However, you can make statements about statements through a process known as RDF reification.  The triples for a single reified statement for nexus would look as follows:

?s ?p ?literal  (statement to be visualized)

The following RDF statements attach a display node to the predicate (?p) and literal (?literal)

?viznode rdf:type rdf:Statement
?viznode rdf:subject ?s
?viznode rdf:predicate ?p
?viznode rdf:object ?literal
?viznode nex:pnode ?displaynode
?viznode nex:lnode ?displaynode

No, RDF reification is not pretty, I know, I'm not a fan of the syntax, but it does allow you to make statements about other statements, and in my case, be used to make indirect statements about specific predicates and literals without having to modify any of the ontologies or resorting to use named graphs (not that this method is bad, I just haven't thought about it yet much).  So, at this point, we have three kinds of display nodes - rnodes (for resources), pnodes (for predicates), and lnodes (for literals).  These three types are actually all the same, but by assigning them different names it is easier to distinguish them from each other when querying the RDF.  This could have been done with a rdf:type statment but this was a bit more compact.  I may or may not change it later.  The W3C RDF working group had a recent discussion of whether RDF reification should be deprecated (see here).  I think the functionality of reification is needed, I just think it's syntax and design need to be re-worked.  For now, it is enabling me to do my arbitrary 3D visualizations.

OpenSimulator Object References
Rather than relying upon OpenSimulator's inventory mechanism and object ID system, objects are stored as RDF and assigned dereferencable RDF URI's which allow the objects to be accessed from remote OpenSimulator regions via the Nexus server code/triple store.  This will allow multiple regions (even if on different grids) to access concurrently the same RDF visualization.  The same RDF URI method could be used as a universal reference to refer to OpenSimulator users and groups (as well as the objects), RDF data interchange between OpenSimulator regions could also be quite handy, but that's another project for another day... :-)  For now, we'll see how well it works within Nexus.

Laying out the RDF Graph
Nexus implements a basic force-directed layout algorithm where the force of the nodes are modeled with Coulomb's Law and the predicates are modeled as springs with Hooke's Law.  When applying the force-layout to the loaded RDF graph (and this can be any RDF graph), the Nexus triples are ignored.  Later down the road, I would like to experiment with various modifications of the force-directed method and/or different methods all together.  I still have a bit of work to do on Nexus force-directed layout engine so that the results are more usable.

Sending the back-end RDF model to the front-end for visualization
The purpose of the front-end is to render the visualization nodes.  The RDF is pulled from the back-end using http and is sent purely as RDF N-Triples.  In an earlier version of Nexus, this was mostly RDF, now it is purely RDF.  When commands are needed to instruct the front-end to do things, the commands are sent as RDF triples.  For example, if I want the front-end to redraw the model, the back-end sends a triple about the session to the front-end as follows:

<http://www.ebremer.com/nexus/sessionmodel/1234567890> <nex:redraw> "true"  (an example)

Turning RDF into DNANexus - Semantic DNA
Back when I attended CSHALS 2010, I had started to write a pdb ontology to express PDB as RDF but shelved it to work on the core of Nexus.  No one else had an RDF representation of PDB that I could find.  Periodically, I checked, and finally during the summer of 2010 I discovered that the Michel Dumontier Lab had written a conversion for pdb and made the conversion program available (pdb2rdf).  And there was rejoicing in the streets!  I had a program now that could do the pdb (protein databank format) to RDF conversion.  The pdb file converted resulted in 16,473 triples.  It doesn't look like pdb2rdf transfers the bonding/connect information in the pdb files yet, so I'm limited to space-filled at the moment.  When the bond information gets added to the RDF conversion, I will be able to do ball and stick views as well.

Now, in order to turn the force directed graph into a visualization of DNA as seen in the first figure to that of the second figure, we would issue the following SPARQL 1.1 commands:

Step #1 - Set all display nodes visible property to false.  The nex:visible predicate tells the server whether to include that visualization node in the final display or whether to even consider it in the layout routines.

modify delete {?s <nex:visible> ?o} insert {?s <nex:visible> "0"} where {?s <nex:visible> ?o}

Step #2 - Set all display nodes visible property attached to atom nodes to true.  We use the predicate "pdb:hasSpatialLocation" to select atoms nodes since the atom nodes are the only nodes that have a spatial location.

modify delete {?rnode <nex:visible> ?o} insert {?rnode <nex:visible> "1"} where {?atom <nex:rnode> ?rnode . ?atom pdb:hasSpatialLocation ?loc . ?rnode <nex:visible> ?o}

Step #3 - We now change the coordinates of the force-directed determined atoms (their visualization nodes) to the crystal-determined XYZ location by reconstructing a vector from the XYZ triples.

modify delete {?rnode <nex:xyz> ?o} insert {?rnode <nex:xyz> ?xyz} where {?atom <nex:rnode> ?rnode . ?rnode <nex:xyz> ?o . ?atom pdb:hasSpatialLocation ?loc . ?loc pdb:hasXCoordinate ?xc . ?loc pdb:hasYCoordinate ?yc . ?loc pdb:hasZCoordinate ?zc. ?xc pdb:hasValue ?x . ?yc pdb:hasValue ?y . ?zc pdb:hasValue ?z . let (?xyz := fn:concat(?x,",",?y,",",?z)) }

Step #4 - The following series of commands sets the nodesize (radius) of the atom visualization nodes to the values that represent the actual atomic radii of the various types of atom present in the structure.  If this data was entered into the system as RDF triples, these six commands could be reduced to one.

modify delete {?rnode <nex:nodesize> ?o} insert {?rnode <nex:nodesize> "1.0"} where {?atom <nex:rnode> ?rnode . ?atom rdf:type pdb:HydrogenAtom . ?rnode <nex:nodesize> ?o}

modify delete {?rnode <nex:nodesize> ?o} insert {?rnode <nex:nodesize> "2.8"} where {?atom <nex:rnode> ?rnode . ?atom rdf:type pdb:CarbonAtom . ?rnode <nex:nodesize> ?o}

modify delete {?rnode <nex:nodesize> ?o} insert {?rnode <nex:nodesize> "2.6"} where {?atom <nex:rnode> ?rnode . ?atom rdf:type pdb:NitrogenAtom . ?rnode <nex:nodesize> ?o}

modify delete {?rnode <nex:nodesize> ?o} insert {?rnode <nex:nodesize> "3.4"} where {?atom <nex:rnode> ?rnode . ?atom rdf:type pdb:PhosphorusAtom . ?rnode <nex:nodesize> ?o}

modify delete {?rnode <nex:nodesize> ?o} insert {?rnode <nex:nodesize> "2.4"} where {?atom <nex:rnode> ?rnode . ?atom rdf:type pdb:OxygenAtom . ?rnode <nex:nodesize> ?o}

modify delete {?rnode <nex:nodesize> ?o} insert {?rnode <nex:nodesize> "3.2"} where {?atom <nex:rnode> ?rnode . ?atom rdf:type pdb:SufurousAtom . ?rnode <nex:nodesize> ?o}

Step #5 - Now for a little flair, we set the shininess of the atom visualization nodes to a glossy metallic value, again, using the "hasSpatialLocation" predicate to pick out the atom nodes.

insert {?rnode <nex:shiny> "3"} where {?atom <nex:rnode> ?rnode . ?atom pdb:hasSpatialLocation ?loc}

Step #6 - We now color all atom visualization nodes to blue

insert {?rnode <nex:color> "0,0,1"} where {?atom <nex:rnode> ?rnode . ?atom pdb:hasSpatialLocation ?loc}

Step #7 - The next five commands color the backbone of the DNA green by selecting atom nodes with a name in the form *' and *'', the backbone atom labels are traditionally labeled with apostrophe and double apostrophe. The last three commands handle the phosphates.

modify delete {?rnode <nex:color> ?o} insert {?rnode <nex:color> "0,1,0"} where {?atom <nex:rnode> ?rnode . ?atom pdb:hasSpatialLocation ?loc . ?atom rdfs:label ?name . ?rnode <nex:color> ?o . filter regex (?name, "''")}

modify delete {?rnode <nex:color> ?o} insert {?rnode <nex:color> "0,1,0"} where {?atom <nex:rnode> ?rnode . ?atom pdb:hasSpatialLocation ?loc . ?atom rdfs:label ?name . ?rnode <nex:color> ?o . filter regex (?name, "'")}

modify delete {?rnode <nex:color> ?o} insert {?rnode <nex:color> "0,1,0"} where {?atom <nex:rnode> ?rnode . ?atom pdb:hasSpatialLocation ?loc . ?atom rdfs:label ?name . ?rnode <nex:color> ?o . filter regex (?name, "P")}

modify delete {?rnode <nex:color> ?o} insert {?rnode <nex:color> "0,1,0"} where {?atom <nex:rnode> ?rnode . ?atom pdb:hasSpatialLocation ?loc . ?atom rdfs:label ?name . ?rnode <nex:color> ?o . filter regex (?name, "OP1")}

modify delete {?rnode <nex:color> ?o} insert {?rnode <nex:color> "0,1,0"} where {?atom <nex:rnode> ?rnode . ?atom pdb:hasSpatialLocation ?loc . ?atom rdfs:label ?name . ?rnode <nex:color> ?o . filter regex (?name, "OP2")}

Step #8 - Lastly, we set the phosphor atom display nodes to glow by inserting nex:glow statements attached to the corresponding phosphor atom display nodes.

insert {?rnode <nex:glow> "0.2"} where {?atom <nex:rnode> ?rnode . ?atom pdb:hasSpatialLocation ?loc . ?atom rdfs:label ?name . filter (?name="P")}

The resulting 3D RDF graph now looks like a DNA model that I had done with my prior Monolith project which dealt exclusively with non-RDF PDB-formatted data.  The DNA structure can be colored and effects set in many different ways by using the powerful new SPARQL 1.1 query language using any of the data present in the loaded RDF graph, not just what is displayed.  We can even access remote SPARQL end points and include their data as well.  Since Nexus handles any RDF, we are not limited to just molecular visualization.  We can branch off into other linked data by using the PubMed ID triple present into the RDF-converted PDB file and link over to PubMed publications data or anywhere else in the LOD (Linked Open Data) cloud.  For those of you thinking "these commands are not easy nor obvious" (perhaps to the SemWeb junkies) you would be correct.  I'm exploring ways in which the commands can be executed visually via the 3D front-end interface, but, I needed a flexible foundation on which to build and the SPARQL-driven engine seemed the best way to achieve this.  As it is, several of the above commands could be re-written to be a bit more compact and fewer, but, I am learning about this stuff myself as I go along.  I'm getting better. ;-)

Next Steps
I've been focused on doing the semantic web/molecular visualization cross-over and now that I've hit that milestone, there is some front-end and back-end work that still needs to be done.  The data is there, but I am not currently displaying any of it in the actual visualization (RDF labels and such).  I would also like to enable  a user to interact with the model graphically.  Interaction now is limited to command-line SPARQL commands only.  I had tossed out the half-SPARQL, half my own concoction commands in favor of the SPARQL.

This year, I did a poster presentation of Nexus combined with work that I have done with my colleagues at Stony Brook University (Dr. Janos Hajagos and Tammy DiPrima) for CSHALS 2011 (see poster here).  In the poster, I mentioned a couple of other things I am working on.  One of them is another Nexus front-end client based on WebGL/HTML5.   I had started this last year, but shelved it while I redesigned the Nexus back-end (server) to be all-RDF that it is now.  Now that the server is working again I will get back to the WebGL/HTML5 client.  As part of that project, I wanted to experiment with using WebSockets rather that http calls between the WebGL client and Nexus.  I will also update the original Nexus client which I did in Second Life, but, it will not be able to render as large of displays as I can in OpenSimulator since Linden Labs limits region objects to 15,000 primitives.  The DNA force-directed model seen here is 26,713 primitives, nearly twice what the Second Life regions allow.  But, I have provisions to allow a limited client to see a smaller window of a larger model.  All three clients will use the same back-end server and will be able to view any of the server models at the same time.  For example, 30 avatars in an OpenSimulator region will be able to work with 30 avatars in a Second Life region along with 30 different WebGL/HTML5 clients at the same time and see changes done from any of the clients live.  RDF breaks down the walled gardens between worlds.

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PDF icon cshals2011-poster.pdf

Nexus 3D RDF Visualization as an OpenSimulator Region Module Displaying Researcher Interest VIVO Data

Submitted by ebremer on

The trouble with triples (not tribbles ;-), for me, is that there are alot of them. Last October, I ported my Nexus 3D RDF Visualizer into Opensimulator and was quite happy with the high availability of graphics primitives that I could use to display larger numbers of triples.  I started working with a set of 31,934 triples that represented the molecular structure of a strand of DNA but realized the programming model I was using wasn't going to scale as far as I wanted.

Nexus, to this point, existed as a massive number of coordinated scripted primitives that communicated to a back-end server that kept them all coordinated.  In my prior post, I was able to display 658 triples of FOAF data without any problems.  This 658 triples amounted to about 935 scripted graphics primitives (prims) and it worked and it was fast.  The front-end operated as a massive parallel processor but when the number of scripts (or in general terms, threads) increases without a corresponding increase in actual physical computation cores, the over-head of the separate threads becomes a liability.  In my case, I was looking at trying to run in excess of 40,000 scripted prims just in the case of the DNA RDF data set. *sighs heavily*  To solve this problem, I rewrote a new Nexus OpenSimulator front-end, not as a series of scripted prims, but as an actual Opensimulator region module.

Region modules are extensions of the core Opensimulator server software.  Opensimulator is written in C#, and being open-source, I was able to dig right in and excercise far greater control of Opensimulator operating at this level than when I was working with the easier, but more limited, scripted prims method.  The following images show a display of 20,002 triples (~25,000 prims - front&back with close ups) which represents about 534 individual SUNY Researchers and their research interests extracted from a VIVO installation that we are developing at Stony Brook (thank you Tammy DiPrima and Dr. Jizu Zhi who are part of that team).  The RDF data was then normalized by using the extracted MeSH terms from the researcher PubMed publications and then linked through a RDF representation of the UMLS (Unified Medical Language System) that was created by my collegue, Dr. Janos Hajagos. 

What is this normalization?  When I first tried visualizing our researcher interests from VIVO in Nexus, I found out that the research interests did not really link up and that I have 500+ little separate RDF graphs.  Why?  Because everyone had their own way of saying the same thing but slightly different.  We took the publication information we had for these researchers and linked it to a RDF version of PubMed that we developed at Stony Brook.  In this linkage, we extracted the MeSH terms (MeSH is part of the UMLS) and then linked and normalized them through the RDF UMLS.  Once this was done, things began to link up.  Multiple datasets linked are more interesting than a single data set. 

At the moment, the Nexus visualization of the data is more interesting to look at than useful.  Removal of the over-linked trivial data which obscures the more useful information needs to be done next.  Hover-text labeling of triples and data-sensitive clustering algorithms are also on the to-do (these features were present in the old front-end).  Fortunately, I did not have to change the back-end for the new front-end because it was my intentions from the beginning to have multiple front-ends connecting to the back-end(s).  Concurrently, I started last fall to develop an HTML5-based/WebGL front-end version of Nexus that would be able to see and share the same sessions as the OpenSimulator-based front-end with an extra twist of using WebSockets rather than http to pass RDF between the front-end and back-end.  Data persistence between sessions is handled thanks to OpenLink Virtuoso being tied to the back-end.  On a personal note, it's a lot of fun playing around with collaborative 3D Semantic Web visualization. :-)

Nexus Commands used:

color <0,1,0> p where {?s ?p ?o} color green all predicates (the sticks that represent the predicates)
color <1,0,0> s where {?s ?p ?o} color red all subjects
color <0,0,1> o where {?s ?p ?o} color blue all objects
color <1,1,1> o where {?s ?p ?o . filter(isliteral(?o))} color white all literals (this would over-write the blue of the last command on literals
shiny 3 spo where {?s ?p ?o} add metalic sheen for all triples

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3D RDF FOAF Graphs in OpenSimulator

Submitted by ebremer on

Here is an image (click on image for larger image) of a model I did earlier with Nexus in Second Life using Tim Berner-Lee and James Hendler's FOAF data linked and visualized in 3D within OpenSimulator with Nexus.  The only code change needed port it over to OpenSimulator from Second Life was the removal of the warppos function since it is no longer needed, however, I think I may have uncovered a small bug/limitation in OpenSimulator URL lengths.  I put a small work-around by shortening the URL's to the FOAF data to avoid the bug when loading from the remote http source, but I will have to go back and figure out what is actually going on and report it if need be to the OpenSimulator programmers.  The Nexus commands used were:

color <1,0,0> spo where { ?s ?p ?o . filter ( ?p=foaf:knows ) }
color <0,1,0> spo where { ?s ?p ?o . filter ( ?p=rdf:type ) }
color <1,1,1> o where { ?s ?p ?o . filter ( isLiteral(?o) ) }
glow 0.2 o where { ?s ?p ?o . filter ( isLiteral(?o) ) }

Since the last time I did this FOAF data, I changed the default shape for literals to cubes and made them smaller so as not to have the literals dominate the scene as much.  Also added were some glow effects to high-light elements of interest.

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