Semantic Networks – Based Approach for Web Services Management
Hassina Nacer
1
and Taous Iggui
2
1
Computer Science Department, University of Science and Technology USTHB, Algiers, Algeria
2
Department of Computer Science, LIMED Laboratory, University of A. Mira, Bejaia, Algeria
Keywords: Services, Web Services Composition, Publication, Semantic Network.
Abstract: As commonly assumed in literature, Web services are software components of distributed applications
which provide services to other applications by using standard Internet technologies (XML, SOAP, WSDL,
UDDI). In this paper, we propose a novel semantic network-based approach for Web services management
in order to facilitate the Web services composition. For answering complex needs of users, the creation of a
composite Web service is required. The Web services composition is one of the big challenge problems of
recent years in a distributed and a dynamic environment. The proposed approach uses an inter-connected
network of semantic Web services describing in OWL-S, using the similarity measure (Outputs-Inputs
similarity) between concepts based on ontologies of domain, built before any submitted request.
Experimental results confirm that the proposed management approach reduces the complexity of the
composition task.
1 INTRODUCTION
Web services are more than distributed systems,
they provide the software foundation for next
generation organisations. To make Web services
accessible to users, service producers use Web
services registries to publish them. Among the
exponentially growing plethora of Web services, the
development of an infrastructure of Web services is
expected to change the business paradigm in the
Web because the current infrastructure of registries
is poor and the mechanism of Web services
composition is inefficient. The Web services
composition is a highly complex task. The proposed
standard (XML, WSDL, UDDI, SOAP) of Web
services technology do not answer the problems of
Web services composition by a software agent.
Furthermore, the semantic annotations for Web
services and requests are not yet mature. According
to (Nacer et al., 2009), the Web services
composition is useful as soon as a client’s request
cannot be satisfied by a single existing service but
by a composite Web service. This later is obtained
from a correct combination of several existing Web
services.
The purpose of this work is to propose an
approach of Web services management in order to
facilitate the Web service composition. This work
uses an ontology-based approach to organize the
UDDI into domains. We suggest, a semantic
network to publish the Web services in UDDI.
This paper is organized as follows. The section 2
covers research issues about Web services
management and composition. In section 3, we
introduce a semantic network as a knowledge
representation of several Web services. In the
section 4, Web services management is discussed as
an application of several semantic networks
merging, and a simple implementation is shown.
Finally in (section 5), we end with concluding
remarks and future works.
2 LITERATURE REVIEW
The Web services technology was concretized
around the specification of the W3C. It is divided
into three areas: (1) Communication Protocols
(SOAP: Simple Object Access Protocol)
1
, (2)
Service Description (WSDL: Web Services
Description Language)
2
, and (3) Service Discovery
(UDDI: Universal Description, Discovery and
Integration)
3
. These current standard revolve around
XML to achieve platform independence features.
Few researches have been done in the area of Web
1
Is a protocol to exchange structured information in a
decentralized and distributed environment
2
It describes only the syntactic interface of Web services
3
Is a virtual registry that exposes information about Web
services
Nacer, H. and Iggui, T.
Semantic Networks Based Approach for Web Services Management.
DOI: 10.5220/0005976100950099
In Proceedings of the 11th International Joint Conference on Software Technologies (ICSOFT 2016) - Volume 2: ICSOFT-PT, pages 95-99
ISBN: 978-989-758-194-6
Copyright
c
2016 by SCITEPRESS Science and Technology Publications, Lda. All rights reserved
95
services management. According to (Yu et al.,
2008), Web services management refers to the
control and monitoring of Web services qualities and
usage. Web services management mechanisms are
coupled with the QoS
4
. The authors identify two
types of management: control
5
and monitoring
6
.
OASIS proposed the Web services distributed
management specification that addresses the
management of IT resources by defining Web
services interfaces and the management of Web
services by defining messages. A Web service
description can be published to multiple service
registries using a variety of mechanisms. These
various mechanisms provide different capabilities
depending on how dynamic the publications using
the service is intended to be. Like all Internet based
computer applications, composition Web services is
one of the most common concerns for
interoperability (Nacer and Aissani, 2014). There
have been several research efforts on Web services
composition. We surveyed Web services
composition development literature from these last
years. Many industry standards have been
developed. Furthermore, many academic research
activities have also been resolved by various models;
Petri Nets (Chemaa et al., 2015), Logical
Programming (Zhai et al., 2015), Markov Process
(Cetina et al., 2015) Matching Algorithm or
Chaining (Ara et al., 2014), AI Planning (Remli et
al., 2015), Graphs (Chao, 2010), Semantic Network
(Nacer et al., 2009), States Machine or Finite States
Automaton (Nagamouttou et al., 2015), Workflow
techniques (Zou et al., 2014), Genetic Algorithms
(Michael and Gero, 2007) (Canfora et al, 2005), and
KP (Tao and Jay, 2005) (Mallayya et al., 2015), etc.
3 USING SEMANTIC NETWORK
AS KNOWLEDGE
REPRESENTATION
3.1 A Semantic Network
Semantic networks are widely used to represent
knowledge, they are a specific class of graphs,
characterized by a huge number of nodes. They are
used in many different fields to model real-word
systems. Semantic networks are consist of nodes and
4
Quality of a Service
5
It aims to improve the service quality through a set of control
mechanisms
6
It rates the behavior of Web services in delivering its
functionalities in terms of quality
and arcs. A node Ni represents the semantic Web
service and a relation defines an arc from the node
Ni to the other node Nj with a label L. This later
indicates the similarity measure between the two
nodes. Furthermore, a set of nodes, labels, and arcs
represents a knowledge as a semantic network. A
knowledge K
1
is given by the following equation:
k
1
= {{N
1
,N
2
,…N
k
}, {L
1
, L
2
,…L
l
}
∪
R
i
j}
(1)
Where k
1
is the number of nodes, l is a number of
labels. A tuple with a set of nodes, a set of labels,
and a set of edges makes knowledge in semantic
network.
3.2 Merging Several Semantic
Networks
It is possible to link sets of knowledge represented in
several semantic networks by using a sharing
operation. As in (Kuwata and Yatsu, 1997), we use
the merging operation. Given n knowledge sets k
1,
k
2
, …k
n
, we can built a global knowledge by adding
labels and edges. This is represented by the
following equations :
k
1
= {{N
1
, N
2
,…N
k1
}, {L
1
, L
2
,…L
l1
}
R
i
j}
(2.1)
k
2
= {{N
1
, N
2
,…N
k2
}, {L
1
, L
2
,…L
l2
}
R
i
j}
(2.2)
k
n
= {{N
1
, N
2
,…N
kn
}, {L
1
, L
2
,…L
ln
}
R
i
j}
(2.n)
Produce the following new knowledge set as k
1
∪k
2
∪...∪k
n
k
1
k
2
k
n
={{{N
1
, N
2
, ..., N
k1
} {N
1
, N
2
, ..., N
k2
}
∪{N
1
, N
2
, ..., N
kn
}} {{L
1
, L
2
, ..., L
l1
} {L
1
, L
2
,
..., L
l2
} ∪{L
1
, L
2
, ..., L
ln
}} {R
i
j }}
The Figure 1 is an example of merging tree
knowledge.
Figure 1: An example of merging semantic network as a
new knowledge.
ICSOFT-PT 2016 - 11th International Conference on Software Paradigm Trends
96
4 WEB SERVICES
PUBLICATION AND
MANAGEMENT
Two dimensions are required for publishing and
managing Web services in order to facilitate the
Web services composition. The two dimensions are
defined as following:
Space: This dimension refers to the space
memory reserved for Web services’ publication
in UDDI:
1. Construction of sub registers of Web services
description.
2. Criteria of classification: Domain’s Web
service application.
3. Storage of sub registers in UDDI.
4. Exploitation of sub registers in Web services
composition.
Structure: This dimension refers to the
organization of Web services in UDDI by using
semantic networks:
1. Semantic network:
- Node: Name of service
- Arc: Semantic relation between two services
(It means the similarity between the Output
of a service and the Input of the following
service)
- Label: Similarity Measure between two
services
2. Measurements of similarity:
- Match: The two concepts are equivalent.
- Subsume: A concept is more general than
another.
- PlugIn: A concept is included in another.
The semantic Web services in UDDI have to be
recorded in a registry in the form of a semantic
network before any submitted request. Each node
represents a semantic Web service and an arc is
labeled by a value which represents a similarity
measure between the output of the service and the
input of the following service. The space’s criterion
provides the first hierarchical classification of Web
services on the basis of work’s activity related to an
ontology of domain. In addition, to refine this
classification, and to reduce the complexity of Web
services composition, it is necessary to refine sub
registers of Web services by specifying the structure.
Furthermore, we can define interconnections
between different Web services of each sub registry
by using concepts and relations based on the model
of a semantic network. Thus, it is very important to
organize semantic Web services in groups, each
group represents a knowledge. We applied the
merging operation on the set of groups. To validate
our proposed approach, we implemented a prototype
in Java.
Let 16 real semantic Web services be in a local
registry without the QoS criteria, the following
Table 1 shows the local registry. The URIs of
services used in the example begin with:
www.mindswap.org/2004/owls/1.1/ (Site, 2009b).
Example: For the service which sid=0, the URI is
www.mindswap.org/2004/owls/1.1/ZipCodeDistanc
e.owl
Table 1: UDDI: Directory of Services.
Sid Sname Inputs Out-puts
Link to
ontology
0
zipCode-
Distance
zipcode1
zipcode2
Dist-ance
ZipCode-
Distance.owl
1 FindZip-Code City, state Zip-code
ZipCode-
Finder.owl
2
zipCode-
Forecasts
lat/long,
temp
forcast
ZipCodeFor-
ecasts.owl
3
EnglishDic-
tion nary
string,
string
string
Dictiona-
ry.owl
4 BabelFish
string,
string
Lan-guage
BabelFishTr
anslator.owl
5
GetTemperatu
re
Zipcode temp
GetTempe-
rature.owl
6
Google
Business
what,
addres
url
GoogleBusi-
nesses.owl
7 ZipCode-info Zipcode info
ZipCode-
info.owl
8
Google
Direction
addres1
addres2
url
GoogleDirecti
on.owl
9
Currency-
Converter
price,
currency
price
Currency-
Converter.owl
10
Bn Price
Check
Book-info
Book-
price
BNPrice.owl
11 GetPres-sure
lat/long,
coast
geo
GetPressurE.o
wl
12 Book Price
Bookname,
currency
Book-price
BookPrice.ow
l
13 Book Finder Bookname Bookinfo
BookFinder.o
wl
14 FindLat-Long zipcode lat/ long
FindlatLong.o
wl
15 Display-Url url info
Display-
URL.ow
Step 1: Classification based on domain of
activity
An example of a sub registry is illustrated in the
Table 2, which is extracted from the previous Table
1.
Step 2: Refinement
An example of a semantic network built from the
information of the previous Table 2 is shown in the
Figure 2.
Semantic Networks Based Approach for Web Services Management
97
Table 2: Example 1: Sub registry.
Sid Sname Inputs Out-puts
Link to
ontology
0
zipCode-
Distance
zipcode1
zipcode2
Dis-tance
ZipCode-
Distance.owl
1 FindZip-Code City, state Zip-code
ZipCode-
Finder.owl
2
zipCode-
Forecasts
lat/long,
temp
forcast
ZipCode-
Forecasts. owl
5
GetTem-
perature
Zipcode temp
GetTempe-
rature.owl
7 ZipCo-deinfo Zipcode info
ZipCode-
info.owl
11 GetPres-sure
lat/long,
coast
geo
GetPres-
surE.owl
14 FindLat Long Zipcode lat/ long
Findlat-
Long.owl
Figure 2: Knowledge 1: An example of a sub semantic
network of Web services.
Step 3: Merging
All semantic networks in UDDI is regarded as a
group knowledge coming from the merging of the
several knowledge. Knowledge
1
, Knowledge
2
, ...
Knowledge
n
.
5 CONCLUSIONS
Despite the importance of Web service composition,
management and publication of Web services have
not been extensively investigated. In this paper we
have discussed the management requirements of
semantic Web services. As a contribution to this
important concern, we have proposed an approach to
managing Web services according to the semantic
requirements of Web services and the concepts of
semantic network and the merging operation.
However, we are also planning to do other
experiments I order to find the best knowledge
representation for publishing and managing semantic
Web services in UDDI.
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