Or.. rather. I knew the api’s well. All the cool technology behind it – I knew that.  The google wave team tackled some tough issues to get it up and running. Google wave included an implementaion of  Operational transforms for largescale realtime collaboration. The google wave api was also pretty nifty.

Now – when thinking about it , I remember email conversations about google wave – facebook conversations about google wave. Real life conversations about wave. Hackathons about wave. I never actually did anything useful in wave itself.  All the fun memories I have about google wave is basically learning about new technologies and meeting new people. There is nothing bad in hacking on interesting tech – during this process I learned about google app engine, cloud computing, python,  protocol design and some longhaired math – all these things are usefull to me in the long run.

It looks like that some of  the technologies of google wave will live on in other google products.  One of the main features – realtime collaboration in documents is now available in google docs.

I have been using jspec on macosx for a while and decided to give it a try on windows vista today. Installing jspec on macosx and linux can be done using the instructions here .

I want to run the automated jspec tests available via rhino at a client site. Sadly , I am forced to use windows there, so I have given some thought on how to make jspec run on windows.

First of all you need to install ruby. I used the automated 1.8.6 One-Click Installer available here . After installing i ran


gem update


the instructions in the README file for jspec currently states that I should install gemcutter and install jspec via that . I was not able to do that on windows ( my system decided to report an obscure runtime error that I did not understand). So i decided to do this instead:


gem sources -a http://gems.github.com
gem install visionmedia-jspec


I let gem install the required dependencies visionmedia-commander and visionmedia-bind. After this I had the jspec script available. Sadly this gave me version 2.7.2 (I noticed \ruby\lib\ruby\gems\1.8\gems\visionmedia-jspec-2.7.2 ) The listing on gemcutter told me that a version 2.11.10 is a avaiable , so I decided to dig deeper. Maybe I could make gemcutter work anyway?

After a little browsing on github.com I found the oneclick installer

I cloned this repo using git

using the following command:

git clone git://github.com/oneclick/rubyinstaller.git


and pressed


rake ruby19


This project creates a sandbox that compiles a working ruby environment using mingw.

After contemplating the insanity of what I was doing for a couple of minutes (remember : installing a working ruby on linux is a single shell command) I grabbed some coca cola and started browsing through the source code for ruby distro while the rubyinstall was compiling. I looked a bit at ruby.c and vm_exec.c and had grim flashbacks to my c days. Luckily the compile finished and I copied ruby19_mingw to my c:\ drive and set it up on my PATH variable. Then I could check which version I was using:


C:\>ruby -v
ruby 1.9.1p243 (2009-07-16 revision 24175) [i386-mingw32]


Now I was able to do:

gem install gemcutter
gem tumble
gem install jspec


(Note that there is information sent to the terminal during these steps)

Now for the interesting part(!) jspec was working , so I could do this:


jspec init SolitaireCipher --freeze


This created a directory where I can train doing the SolitaireCipher using javascript. I renamed lib/yourlib.core.js to lib/SolitaireCipher.js and spec/spec.core.js to spec/spec.SolitaireCipher.js and spec/spec.dom.html accordingly.

After 20 mins of fiddling I managed to get some running tests in a browser by opening spec.dom.html. Then I decided I want to automate the tests using mozilla rhino. After installing rhino , I could run automated tests like this


cd c:\projects\SolitaireCipher
jspec --rhino


This opens up a proces that listens to file changes in the lib and spec folders. All very well – untill I discovered that jspec currently uses ANSI codes to render colors to the terminal screens. ANSI codes are not supported on windows vista (something with ANSI.SYS being obsoleted), so if I want the nice colors then I need an alternative terminal than my command prompt in vista.

I found rxvt available from PortableGit on google code. This renders the colors just nicely – but has some other drawbacks. If I just use rxvt for rendering feedback from the jspec tests, then it seems to work though.

One thing to note is that rhino needs the java sdk to be installed and js.jar needs to be on your CLASSPATH. when starting jspec from rxvt on the msys from PortableGit, then CLASSPATH could be set like this (assuming rhino is installed in c:\tools ):


export CLASSPATH=/c/tools/rhino1_7R2/js.jar


I probably want to avoid using rxvt on PortableGit too much . There are some major flaws listed here .

Maybe I should look into doing a adobe air frontend for jspec?

The central insight of BDD is that TDD is really computer aided specifications of the executable behaviour of your system. BDD tries to express this using a Domain Specific language.

Back in 2006 , Dave Astels described how to ascend from the focus on 1-1 testing of production code to use the test proces as a way to describe the way you want your system to behave.

In the video Dave makes the valid point that “The words you use shape how you think”. So we should go away from thinking about “testing” constantly to think about describing how you want your system to work.

So to me – BDD sounds like a kickstart to be productive in TDD – and do it well from the start. So if you are starting out on TDD , you should really start out doing BDD.

Dave walks through some examples using rspec in ruby. I am currently using jspec

Let’s take a an example of how to develop and test a music video search and storage system. A traditional way of developing this would require formulating a object oriented system architecture, thinking about streaming and metadata enabled search. The system architecture could consist of a well chosen database server, a streaming server and a metadata enabled search engine – combining these technologies with a modern UI and encapsulating theme in carefully designed object oriented structures. During all these important choices , and all during development we would make sure to write tests before we write a single line of code.

All these things put together would lead to a well thought out system architecture , but all the effort put into the system architecture can be in vain – if we don’t have a solid business understanding of what a video storage system should do. What will the users expect?

While browsing on facebook this other day I found the “The Paris Hilton & Jacques Derrida Appreciation Society” – this group explores the connections between the works of Paris Hilton and Jacques Derrida. When we deconstruct the “pretty blonde” facade of Paris Hilton, then you can actually find some deep insights. Take “Nothing in this world” for instance:

Take the phrase “when you are with somebody else, that’s me in your eye”. There is the obvious interpretation of the sentence . But thinking about that sentence also let’s you reflect on the real meaning . When you look at Paris Hilton in this video, what do you see? Do you see the pretty blonde or the millionaire , hard working young girl . In this video I am seeing the image of the pretty blonde – but I am also thinking about the millions of dollars she is earning portraying herself in this way. So in a sense – I am reading the original message out of context. I am admiring what Paris Hilton in some other way than she intended – the original meaning of the words seem to have disappeared – but my understanding of the sentence is more useful to me. I wish I could do what Paris Hilton does – but in a way that would make sense in my world .

The producers of the “Nothing in this world” video are not likely to convey information about the business empire of Paris Hilton in the metadata supplied for the video. So a system formulated as a “video storage system” would not let me exploit the information I found in the facebook group.

BDD introduces the use of a Domain Specific language to express the users expectations in a manner more directly focused on the behavioural aspects of the system. This lifts the clouds from the system aspects and focuses on intent.

A better way to formulate my expectations for the system would be:

Describe the music video storage system:
  I should be able to search for videos using metadata
  it should play videos  in my browser
  I should be able to query facebook for information about it
  

If I had those expectations formulated to me , then I would choose to implement this system as a mashup between youtube and facebook as a facebook application. This would be a radically different system architecture than the one describe above.

Furthermore , by leveraging one of the several BDD test frameworks available, then the expectations could be formulated in way that can be used as tests.

To me the concept of “information” only makes sense if it can be extracted or related using wellknown techniques. In this sense “information” is put in the context of a “subject” and a “object” , e.g. the information identifies facts about the “object” in a manner that is understandable for the “subject”. When information allways should occur “in context”, then it should be clear that the information should be codified in a manner that is understandable by the “subject”.

This “codification process” is successfull when the information about the “object” is conveyed to the “subject” in a manner that is easily understood – so in my interpretation “information” can be expressed in many ways , and still be intended as the same information about the the same “object”.

In most concrete circumstances involving human communication “codification” will mean “telling” somebody “else”. E.g saying “I am hungry” .. or “do you mind passing me the water”. Information is revealed through use of language in a sentence and placed in the context of the situation where the sentence is spoken.

In most traditional computing software information is stored to examine facts about phenomena or physical items. The wealth of information in context has been lost in the process of gathering these facts. Take a traditional supply store. It is not very common for the desk clerk to capture the facial expression of the customers while entering the items bought in the cash register. So in this way, the information from the facial expression is available to the desk clerk but not the store manager.

In our current computing systems, then it is not easy to compute “the mood of the customers” – but if we understand the wealth of information lost in the “codification process” then we can exploit this for a better understand of the market siutation . But we will still not be able the compute the “mood of the customers”.

So – to me information can only be understood as “information in context”. I will try to design complex systems from this where it makes sense.

Det har dog bæret sådan at det bliver lidt bøvlet at vedligeholde diverse images rundt omkring – og Google App Engine for java stiller væsentlige begrænsninger på hvordan man kan skrive SQL – og det kan blive vanskeligt at få benyttet GIS operatorer på GAE (Bemærk at jeg slet ikke har prøvet microsofts nye Azure platform)

Bob McWhirter kører iøjeblikket et projekt for jboss , hvor han iøjeblikket eksperimenterer med puppet til at administrere virtuelle maskiner. Jboss håndterer udviklingen under projektet jboss cloud . Ideen er at man kan benytte “metaappliance” til at generere de øvrige “appliances”. Jboss understøttede clustering allerede fra version 4 – det nye i eksperimentet er nu maskin-håndteringen, hvor deployment-platformene inkluderer ec2, vmware, kvm .

Jeg håber at kunne bruge jboss-cloud projektet til at håndtere mine udviklingsservere på en mere fornuftig vis


class Ting_Client {
var $opensearch = "http://didicas.dbc.dk/opensearch/";

public function search($query){
$hc=new HTTPClient();
$url = $this->opensearch."?action=searchRequest&query=$query&facets.number=10&outputType=json";
$host = $hc->extractHost($url);
$hc->connect($host);
return( $hc->Get($url) );
}
}


Her antager jeg at din php klient også kan hente HTML sider ligesom min kan . På den facon kunne man tænke sig noget i denne her stil:


$t=new Ting_Client();
$searchResponse = json_decode($t->search($query));
if($searchResponse->searchResult->hitCount>0) {
print "

\r\n";
foreach( $searchResponse->searchResult->records->tingRecord
as $rec){
$isbn=$rec->dc->identifier[0];
$isbn=preg_replace("/ISBN\:/","",$isbn);
print "
• ".$rec->dc->title[0]."

";
}
}


hvor beskrivelsen på de enkelte poster kan benyttes til at lave et mashup. Jeg har her prøvet med slashdemocracy, men det virker vist ikke helt for andet end ISBN.

Da jeg kiggede på outputtet fra ting , så undrede jeg mig lidt over hvorfor at man ikke havde valgt at bruge Z39.50 , men det er så også ok. Når man har kigget på outputtet fra ting i et stykke tid, så giver det nogenlunde mening.

]]> http://www.pedant.dk/2009/06/28/nada-ting-kan-ogsa-json/feed/ 0 http://www.pedant.dk/2009/06/27/ding-pa-github-mine-f%c3%b8rste-20-minutter/ http://www.pedant.dk/2009/06/27/ding-pa-github-mine-f%c3%b8rste-20-minutter/#comments Sat, 27 Jun 2009 21:29:40 +0000 Jacob http://www.pedant.dk/?p=455 Jeg fald lige over http://github.com/kdb/ding/tree/master på github, hvor Københavns biblioteker er igang med at kode en drupal baseret frontend til ting projektet. Nu er jeg jo ikke lige en haj til drupal og php , så jeg startede med at nøjes med at kigge på en klient til php5. Den var også enormt kompliceret , så jeg skøjtede videre til http://didicas.dbc.dk/opensearch/opensearch.wsdl og prøvede at lave en php5 webservice klient vha nusoap.

Den virkede ikke lige, så prøvede jeg istedet at skrive “wsdl http://didicas.dbc.dk/opensearch/opensearch.wsdl” på kommandolinjen (her var det heldigt at jeg havde installeret Windows SDK’et ) . Den kommando lavede filen tingService.cs til mig .

Jeg så straks at designeren af skemaet kan lide lower camelcase - det undrede mig dog at typerne resulterer i små begyndelsesbogstaver for mine klasser.

Ved at kigge lidt i tingService.cs så jeg hvilke parametre man skulle bruge . Jeg ved ikke lige hvad formatType og sortType skal bruges til ,så jeg lavede bare en default constructor på den. Det førte til flg kode:


using System;

public class test {
public static void Main(){

tingService t=new tingService();
searchResult sr = t.search("test", "", null, new formatType(), true, 1, true, 5, true, new sortType(), true);
Console.Write(sr.hitCount);
//Console.Write(sr.records[0].relations[0]);
}
}


jeg kompilerede koden med “csc test.cs tingService.cs” og fik umiddelbart en køretidsfejl. .NET frameworket rapporterede om en Ikke-afviklet undtagelse ifm en HTTP fejl 301 hvor det blev meddelt at endepunktet var flyttet til http://didicas.dbc.dk/opensearch/

Efter at have tilføjet et “/” til endepunktet for servicen i tingService.cs , så kunne jeg se at der er “1320″ svar på søgningen “test” .

Jeg kan se at resultaterne bliver afleveret i en struktur kaldet “tingRecord” i det returnerede searchResult, men jeg kan ikke umiddelbart overskue hvordan man hiver resultaterne ud derfra. Jeg vil prøve at følge lidt med i projektet og kigge lidt nærmere på wsdl filen ved lejlighed

]]> http://www.pedant.dk/2009/06/27/ding-pa-github-mine-f%c3%b8rste-20-minutter/feed/ 0 http://www.pedant.dk/2009/05/30/en-maskine-der-siger-bing/ http://www.pedant.dk/2009/05/30/en-maskine-der-siger-bing/#comments Sat, 30 May 2009 10:53:22 +0000 Jacob http://www.pedant.dk/?p=418 Jeg prøver at følge med i hvad der sker inden for søgemaskine-feltet . Det forlyder at Microsoft også har opfundet en maskine der siger Bing:

Microsoft har beskrevet den nærmere her :

]]> http://www.pedant.dk/2009/05/30/en-maskine-der-siger-bing/feed/ 0 http://www.pedant.dk/2009/02/14/om-autoriteter-i-brugerskabt-indhold/ http://www.pedant.dk/2009/02/14/om-autoriteter-i-brugerskabt-indhold/#comments Sat, 14 Feb 2009 16:11:28 +0000 Jacob http://www.pedant.dk/?p=216 Den bedste internet søgemaskine på markedet idag er baseret på begreberne ‘hubs’ og ‘authorities’. En ‘authority’ opfattes som en side der er central i et netværk for et givent emne og opfattes af netværket som centralt for emnet. En ‘hub’ er et knudepunkt i netværket der indeholder mange henvisninger til øvrige steder.

Efterhånden som flere og flere steder på internettet tillader brugerskabt indhold så mener jeg at vi må ændre på beregning af autoritet vha af henvisninger i et netværk. F.eks på ‘blogs’ så indeholder kommentarer typisk en henvisning tilbage til hjemmesiden til ham eller hende der har skrevet kommentaren, derved vender vi op og ned på hvad en ‘hub’ og en ‘authority’ er – idet linket nu går den anden vej i kommentaren.

Den traditionelle ‘hubs’ and ‘authorities’ model

Hvis vi i den traditionelle situation betragter et endeligt antal websider uden brugerskabt indhold i et sæt {1,2, … ,n} så kan vi opstille en matrice B med links i mellem de forskellige websider hvor 1 markerer at der link mens 0 markerer intet link – indgang (i,j) i B markerer så at der er et link fra i til j.

Hvis vi så yderligere betragter ‘hubs’  som og authorities

Så kan vi beregnene vægtene i netværket således :

og     

Hvis vi itererer en gang så når vi

og  

næste iteration giver

og

Den matematisk kyndige læser vil her indse at at resultaterne vil konvergere imod de principielle egenvektorer for og

Rent intuitivt ses det at samlingen af autoritetsvægte for siderne i netværket udtrykker at en gennemsøgning i netværket vil have større sandsynlighed for at ende på en side hvor vægten er større end på en side hvor vægten er lille.

Google har benyttet princippet til at opstille deres PageRank



Hvor er antallet af links ud fra side og d er valgt til 0.85.

Min mulige ændring af beregning af autoriteter

Når vi betragter modeller hvor “autoritet” tages som et udtryk for at en læser vil have høj sandsynlighed for at opleve en henvisning fra side A til side B som autoritet, så vil et brugerskabt links fra A til B have mulighed for at vende situationen om. Et kendt eksempel er ved brugen af blogs, hvor en hyppig bruger af mange blogs vil opnå mange indgående links (Man kunne kalde det en ‘invers hub’). Brugen af henvisninger i brugerskabt indhold går nu fra at være en måde at udtrykke mening om relevans inden for et emne til at udtrykke interesse for et emne.

Det er så her at jeg tænker på om man kan finde de typiske steder hvor brugeren af blogs skriver på og foretage tilpasninger af link-beregningen der. Lad os antage at vi kunne finde en passende måde at beregne om der er tale om lille koncentreret klynge af websteder der henviser til hinanden . Efter at have opnået listen af sider kunne vi ændre på den vægt der tilføjes pr iteration ved betragtninger over linkafstanden til klyngecenteret. Altså at hvis vi betrager et websted , der er inde i den lille klynge, så har et link ikke så stor betydning som hvis det optrådte udenfor.

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