Ontologyenhanced Semantic Request and Response OSRR The New Paradigm for Geospatial Semantic Web Ser

1
Ontology-enhanced Semantic Request and Response
(OSRR) - The New Paradigm for Geospatial Semantic
Web Services
Xuan Shi West Virginia University Xuan.Shi_at_mail.wv
u.edu
2
Overview

• Web services problems in the old paradigm
• Semantic Web services goals and chaos
• OSRR an alternative solution and challenge
• Semantic Interoperability consensus vs. logics

3
Web services
4
Problems with Web services

• Ambiguity in definition
• Web service may NOT have any relation with the
  Web.
• Web service is the solution of software
  interoperability, taking the places of CORBA and
  DCOM
• A service is a functional component of the
  software package, accessible through programming
  interface (API)
• (Web) service is not a Web site, or Web-related.

5
Desktop GIS
6
Problems with Web services

• Geographers, and other scientists and engineers
  who are not programmers, cannot use Web services
  even if they can find the required services that
  are only accessible through APIs
• Web Services Description Language (WSDL) defines
  the programming interface at the syntactic level,
  not semantic even programmers cannot understand
  the meaning of the service

7
Semantic Web services

• Goal enable the dynamic and automatic service
  discovery, matchmaking, composition and invocation

8
Semantic Web services

• Chaos service registry died !
• SAWSDL targets service interface
• OWL-S/WSMO assumption-based, target Web site
  related activities
• Dynamic invocation has been ignored

9
SAWSDL

• Add semantic annotation onto WSDL elements

• matchType a subclass of string.
• What does matchType mean if the value A

• matchType a subclass of hex code.
• If the value A, matchType means 10 !

• What should I do if matchType A ?!

Hex numbers use 16 digits 0 1 2 3 4 5 6 7 8 9 A
B C D E F
10
OWL-S/WSMO
Virtual Travel Agency (VTA) use case of service
aggregation/mediation (Modified from Semantic Web
Services Tutorial authored by Stollberg, et al.
2005)
- Supposed semantic Web is available (not true) -
Supposed the required services can be discovered
(not true no service registry) - Supposed the
discovered services have a feature of "exact
match" to those proprietary ontology definitions
(since same services may have different APIs and
WSDLs, discovered services may be similar or
related to each other) But even OWL-S is not
compatible with WSMO, let alone any solution to
the semantic interoperability.
11
Dynamic service invocation

• The dynamic invocation of Web services is
  envisioned as without any reprogramming, a
  software system could have the flexibility to use
  various services that do the same kind of job but
  have different APIs (Burstein, 2004)
• Such a statement means that
• Service semantics (what services do) are not the
  same as service interfaces.
• Service semantics can be the same (do the same
  job) but the service interfaces are different.

12
Standardized APIs for ALL Kinds of
ServicesFunction getService(String request)
String response
Input a1, a2, x2, x3, y1, y3 Output z1, z2, z3
Input x1, x2, y1 Output m1, m2
Input x1, x2, y1, y2 Output z3
13
Semantic Request and Response
14

• Geographers, and other scientists and engineers
  who are not programmers, can use Web services
  through SRR when they can find the required
  services

15
Reverse Engineering For a Reconstruction
16
OSRR O for Service Discovery and Matchmaking

• Semantics of Web services
• What are the Web services and what functions do
  they offer?
• How does the service requester send the request
  to deploy the service and function?
• What service output result can the requester
  expect after the invocation?

17
OSRR O for Service Discovery and Matchmaking

• Five building blocks in OSRR
• Service domain and function category description
• Format of the service request input XML document
• Format of the service response output XML
  document
• Service request input requirements defines the
  template for service request
• Service response output prototype defines the
  template for service response.

18
Semantic Interoperability
The word semantic represents the meaning of.
The semantics of something is the meaning, or
an interpretation of the meaning, of something.
Ontology could be described as a formalized and
shared specification of a common
conceptualization of a domain knowledge (Gruber,
1993 Uschold, et al., 1996),
19
Semantic Ambiguity
HTML is not semantic, for it is not
machine-processable
WSDL is not semantic, although it is
machine-processable
20
Semantic Interoperability
Ontology lttaxonomy, logical inference rulesgt,
and taxonomy can be expressed as Taxonomy
ltclasses, relationsgt (Alesso, 2004).
Veltman (2004) concluded that, a semantic Web
which deals only tangentially with meaning might
more accurately be called the transactions web
(EDI redivivus) or the logic web. Those who
designed semantic Web consider that, logical
meaning is the only objective dimension of
meaning that all other meaning is subjective and
therefore unimportant. In this view, the semantic
web rightfully limits itself to the realms of
logic. In science, technology and business this
claim leads to pragmatic results.
21
Semantic Interoperability SW vs. SWS
Concepts defined in Semantic Web are meaningful
ltrdfRDF xmlnsrdf"http//www.w3.org/1999/02/22-r
df-syntax-ns" xmlnsdc"http//purl
.org/dc/elements/1.1/"
xmlnsfoaf"http//xmlns.com/0.1/foaf/" gt
ltrdfDescription rdfabout""gt
ltdccreator rdfparseType"Resource"gt
ltfoafnamegtSean B. Palmerlt/foafnamegt
lt/dccreatorgt
ltdctitlegtThe Semantic Web An Introductionlt/dcti
tlegt lt/rdfDescriptiongt lt/rdfRDFgt
Terms used in WSDL are meaningless symbols
22
Limitations of RDF/OWL
23
Limitations of RDF/OWL
RDF/OWL does not understand 2 3 5
- Service a provide address geocoding service
that retrieves the latitude and longitude of an
input address - Service b provides a service to
convert latitude and longitude into another
coordinate pairs with a different projection
system such as UTM - Service c provides a service
to directly retrieve the UTM x, y coordinates
from the input address Service c a b
24
Semantic Interoperability Consensus vs. Logic
Modeling
What is the ontology and semantics of the Prime
Meridian? Is Prime Meridian based on consensus
or logic modeling? Is GML a formalized, shared
specification of a common conceptualization? Fir
st Class High Way (USGS) Interstate Road
(USDOT)
Modeling Prime Meridian ? Amsterdam, Athens,
Bern, Helsinki, Lisbon, New York, Oslo, Peking,
Paris, Rome, Tokyo, or Stockholm ?
In scientific research, we just need one evidence
to deny a hypothesis or theory
25
Semantic Interoperability - beyond the logical
relationships
Owner a Polygon A (1,3 3,5 5,3 3,5 1,3) Owner b
Polygon B (2,5 4,7 6,5 4,3 2,5) Owner c Polygon
C (4,4 6,6 8,4 6,2 4,4) Owner d Polygon D (4,5
5,6 7,4 6,3 4,5) Owner e Polygon E (2.5,4.5 3,5
4.5,3.5 4,3 2.5,4.5)
A touches C B touches D B intersects A B
intersects C C contains D D is contained by C E
is the difference of A and B
How to define the topological relation between
the geometric features through logical modeling?
? What is the Union of A and B Excluded by the
Difference of A and B ?
26
Semantic Interoperability
Objective OR Subjective relationship among
geometric features?
?
We need more consensus, agreements, standards,
not Logic Modeling
27
Thank You! Questions?