Web-services for sensor-based and location-aware products

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Web-services for sensor-based and

location-aware products

Kaj Grønbæk

with contributions from Raghid Kawash and Allan Hansen Department of Computer Science,

University of Aarhus, Denmark

itPDP12 Kaj Grønbæk

AARHUS UNIVERSITET

Plan

› About the project requirements (in Danish) › About integration of sensor data in Web apps

› Web feeds › Sensor Web › SensorML

› About location based Web apps

› Inspiration Endomondo/Garmin › KML

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Project Requirements for Web-services

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Mål og afgrænsning for it-produktet

› It-produktet skal placeres klart i et af de tre temaer

› Udvise forståelse og respekt for målgruppens behov.

› Løsningen skal positionere sig som relevant i forhold til de forventede brugere af teknologien.

› Der skal tages højde for målgruppen og typen af lidelse/støtte, der adresseres

› Løsningen skal omfatte flere klienter og servere (evt. peers),

der benytter web-standarder

› Kontakt til professionelle støttepersoner, social kontakt i målgruppe, automatisk indsendelse af sensordata.

› It-produktet må gerne involvere en mobiltelefon som en del af løsningen, men der skal være et samspil med andre fysisk designede elementer i omgivelserne

› Der skal argumenteres for det forretningsmæssige potentiale og behov for produkter

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Webservices – fra opgaven

› Programkoden for gruppens web-service skal installeres på server der gør det muligt at afprøve systemet, endvidere afleveres koden som en separat ZIP-fil med en README-tekst-fil, der beskriver brugen af jeres Web-services. Endelig vedlægges en kort tekst, der beskriver funktionaliteten og argumenterer for jeres implementation. Denne vil blive bedømt på følgende kriterier:

› Hvor avanceret funktionalitet stiller web-servicen til rådighed? Diskuteres valg blandt alternative teknologier, til at løse opgaven?

› Er der kendte mangler i implementationen eller andre ændringer i forhold til jeres plan (delafleveringen)? Eller nye ideer til forbedringer?

› Er den overordnede struktur af programkoden beskrevet?

› Er interfacet til Flash- (Web- eller Mobil-) delen klart beskrevet (så denne i princippet kunne implementeres uafhængigt af web-servicen)?’’

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Airstrip example:

Cardiology measuring via cell phone

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HealthBarometer – Caretech Innovation

› Daily health coaching

› In context of everyday work and life situations

› e.g.via Mobile device › “What if…” simulations…

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Internet of Things - Stream feeds

Internet

A hierarchy of stream feeds (fusion trees) A fusion feed, which is a composition of two other stream feeds

› Like web feeds

› Extend web feeds with the notion of

real-time streaming of sensor data › Fusion trees

› Conditional subscription over temporal scopes:

All time Historical Real-time Internet

Your System (subscribes to)

•  Example of a Stream-feed URL: http://www.somedomain.com/streams/radiator/real-time feedback Publish Future Past itPDP12 Kaj Grønbæk AARHUS UNIVERSITET

How Do Stream

Feeds work?

These aspects can be implemented – using open source toolkits

Client Apache/Tomcat

Web Server

A stream feed

Subscribe to feed Feed + listen to port

Connect Data Data Data Pull feed Data (feed) React Your System Server pushes updates Clients pull updates Clients wait for updates Your System Maybe a Stream feed Servlet? Pull

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What are web feed?

› A web feed is an XML document + DTD - frequently used to publish content by content providers

› A DTD defines the building blocks for the web feed › Content providers have web sites with frequent updates

›  They provide these updates by means of web feeds

› Other may read web sites and and provide web feeds for these sites (3rd party web feeders)

› Users want to be constantly updated with new information from the web

› They use feed readers - aka aggregators

› These tools help them organize frequently updated

information on the web

Client-side based Aggregators Server-side based Aggregators itPDP12 Kaj Grønbæk AARHUS UNIVERSITET

How do

web feeds

work?

The Web Desktop computer Server Web browsing Laptop Enterprise Network LAN

Some other Server

iPhone

XML/HTTP/TCP

VPN/Router

•  Hyper Text Transfer Protocol (HTTP)

•  Identify feeds using DNS + URLs Content providers

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How does it really work?

•  Web feeds e.g. RSS and Atom are XML based documents transmitted on the web

•  HTTP Primitives are used to Create, Update, Read and Delete Atom web feed POST GET DELETE

HTTP primitives: PUT

Web Server Client

- Create feed using POST

- Consume feed using GET

- Update feed using PUT

- Delete feed using DELETE

Resources (feeds) identified using URLs

Web servers understands these types

of requests XML XML XML XML Your System Atom Publishing Protocol: itPDP12 Kaj Grønbæk AARHUS UNIVERSITET

Example of an Atom

web feed

<?xml version="1.0" encoding="utf-8"?> <feed xmlns="http://www.w3.org/2005/Atom"> <title>Example Feed</title>

<link href="http://example.org/"/>

<updated>2003-12-13T18:30:02Z</updated> <author>

<name>John Doe</name> </author>

<title type=“text” >Atom-Powered Robots Run Amok</title> <link href="http://example.org/2003/12/13/atom03"/> <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id> <updated>2003-12-13T18:30:02Z</updated>

<text>…</text>

<summary>Some text.</summary> </entry> </feed> Uniquely identifies the entry Who published this feed Uniquely identifies the feed

There are many more elements and attributes We can also use mime-media types We can add our own attributes

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Feeds in

PHP

› Feedwriter itPDP12 Kaj Grønbæk AARHUS UNIVERSITET

Programming Web Feeds

Java based e.g.

› http://www.vogella.com/articles/RSSFeed/article.html

› http://sourceforge.net/projects/jrss/ PhP based, e.g.

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Some historical Info

› Many formats

› Rich Site Summary (RSS 0.91) › RDF Site Summary (RSS 1.0, RSS 0.9)

› Really Simple Syndication (RSS 2.0) – used by many › ATOM 1.0 – Alternative to RSS

› Most of which are to some extent incompatible

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Designing Your Database

› The simplest is to use the existing Atom mode

Entry * Feed 1 EntryState - Historical - Latest - Title - Id - Author - Id - etc.. - etc… - etc…

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MySql and Web scripts on CS servers

› You have to run the following script in a termnal window on a CS horse

› /users/mysql/linux/daimi/muser

› It will return a database with login info for you. › Following that you can admin your database via

phpmyadmin on mysql.cs.au.dk.

› You should place your Web scripts under public_html on your own account.

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Sensor Web

Sensor web papers and standard

› http://dx.doi.org/10.1145/1621890.1621898

›  http://www.cloudbus.org/papers/ICISIP2006-SensorWeb.pdf

› http://www.opengeospatial.org/

› http://opengeo.org/publications/opengeo-swe/

Sensor network projects related to healthcare › http://fiji.eecs.harvard.edu/CodeBlue › http://static.usenix.org/event/mobisys05/eesr05/tech/ full_papers/hashmi/hashmi.pdf itPDP12 Kaj Grønbæk AARHUS UNIVERSITET

SensorML Elements

!

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Example of SensorML

<Quantity observable type=#windSpeedunitOfMeasure=#mph>134</Quantity> </maximum> </dynamicRange> <threshold> <Quantity observableType=#windSpeedunitOfMeasure=#mph>2.2</Quantity> </threshold> <survivableRange> <maximum> <Quantity observableType=#windSpeedunitOfMeasure=#mph>220</Quantity> </maximum> </survivableRange> <operationalRange> <minimum> <Quantity observableType=#airTemeratureunitOfMeasure=#celsius>-40 </minimum> <maximum> <Quantity observableType=#airTemeratureunitOfMeasure=#celsius>40 </maximum> </operationalRange> </GeneralPropertyModel> </response> itPDP12 Kaj Grønbæk AARHUS UNIVERSITET

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Sensor Readings and Visualization

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Sketch your scenarios…

Home1 Person2 Person1 Home2 Pharmacy Hospital Welfare Services Physician Stationary Sensors Mobile Sensors SensorML SensorML XML XHTML XHTML SmartPhone Apps

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QUESTIONS?

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Web-services for location-aware

products

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Endomondo.com

itPDP12 Kaj Grønbæk AARHUS UNIVERSITET

Garmin

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Hasle Running Coach

- Prevention

›

KML based data format

› KML / KMZ

› Running routes + coach › Logdata

›

Existing players

› Google Earth › Google Maps › ... itPDP12 Kaj Grønbæk AARHUS UNIVERSITET

How to represent the data?

› Database approach

› Data is managed by a geographic information system (GIS)

› A GIS supports user created searches (interactive queries), data editing, analyzes of spatial information, and visual presentation of these results on maps.

› Document approach

› Data is distributed in files or documents. › Files are read by geo-browsers (Earth Viewers).

› Functions in much the same way that Web-browsers read distributed HTML files on the Web.

› The two approaches can be combined e.g. documents can be generated from a GIS database system, and/or the documents can have “live” links to the GIS database.

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KML is becoming the de facto standard

for location based mark up of maps

KML = Keyhole Markup Language (an XML based language)

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KML: a geographic document format

› Keyhole Markup Language (KML) is an XML-based language for

geographic documents.

› Originally created in 2001 by Keyhole Inc. for use in the “Keyhole Earth

Viewer” geo-browser.

›  “Keyhole” refers to the nickname of the American KH-11 spy satellites launched in the 1970s.

› Keyhole Inc. was acquired by Google in 2004. › Google Earth (re-)launched in 2005.

› KML 2.2 was ratified as an open standard for geo-browser by the Open

Geospatial Consortium in 2008.

› Used as document format by many geo-browsers,

both 2D, 3D and mobile:

›  Google Earth, Google Maps, Google Mobile Maps, ›  Microsoft Virtual Earth, Live Search Maps, ›  Yahoo Pipes, …

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KML: Spatial Objects

› KML defines a lot of useful objects for presenting spatial data

› E.g. place marks, tours, images, lines, polygons, 3D models, textual descriptions, annotations, time based data, etc.

› Each object has a spatial placement and style information that specifies how the object should be presented.

› KML also supports specifications of how the camera should look at objects

›  This is harder to implement correctly, since 2D and 3D browsers may not support the same views, e.g. tilt and rotation.

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Hello World! (Google Earth)

› Simple PlaceMark

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Hello World! (KML)

› Line 1: XML declaration (must be valid xml)

› Line 2-12: KML element. Defines the kml namespace. › Line 4-10: A Placemark object. The placemark includes:

› A name that is used as the label

› A description that appears in the "balloon" attached to the Placemark

› A Point that specifies the position of the Placemark (longitude, latitude, and altitude)

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How to to look at objects

(The <Lookat> element)

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Paths

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Styles: Shared styles for objects

› Styles can be applied to Geometry, Placemarks, and Overlays defined in the Document.

› A Style is defined with an ID.

› A Style is defined once, and can be reference multiple times, using the <styleUrl> element.

› Styles can be embedded and used within the same file.

› <styleUrl>#transBluePoly</styleUrl>

› Or it can be loaded from an external file.

› <styleUrl>http://www.example.com/file.kml#transBluePoly</styleUrl>

› This is much like CSS style declaration in HTML (but not cascading).

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Network Links

› Network links support loading external data

› KML files, images, or models

› Loading can be time based or view based

› E.g. an external kml file, can be reloaded with a certain interval

› Network links are defined by the <NetworkLink>, <Link>, and <href> elements.

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Working with KML documents

› KML files are simple XML files and can be created and edited in any text editor.

› Google Earth has some editing facilities as well

› It is possible to export a folder from Google Earth to KML/KMZ › It is possible to copy objects in Google Earth

›  When pasted, you get the KML representation

› But KML can also be generated by programs or Web services on the fly from other data…

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Working with KML documents

(Web services)

› KML Generator:

› A simple PHP Web service that generates:

›  Network linked ›  A number of place marks

› Static Map Generator:

› A simple service that uses the above generated KML and creates a google static image with the place marks on top

KML References

› Googles KML documentation ›  http://code.google.com/intl/da/apis/kml/ ›  Tutorial ›  http://code.google.com/intl/da/apis/kml/documentation/kml_tut.html ›  Developer's Guide ›  http://code.google.com/intl/da/apis/kml/documentation/topicsinkml.html ›  KML Reference ›  http://code.google.com/intl/da/apis/kml/documentation/kmlreference.html › Books

›  KML Handbook, The: Geographic Visualization for the Web

›  http://www.informit.com/articles/article.aspx?p=1276353

› Blogs and discussions

›  http://googlegeodevelopers.blogspot.com/ ›  http://groups.google.com/group/kml-support ›  http://www.gearthblog.com/

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Web-services for sensor-based and location-aware products