=Paper=
{{Paper
|id=None
|storemode=property
|title=Fuzzy XML with Implementation
|pdfUrl=https://ceur-ws.org/Vol-920/p58-panic.pdf
|volume=Vol-920
|dblpUrl=https://dblp.org/rec/conf/bci/PanicRS12
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==Fuzzy XML with Implementation==
https://ceur-ws.org/Vol-920/p58-panic.pdf
Fuzzy XML with Implementation
∗
Goran Panić Miloš Racković Srdjan Škrbić
Ðure Jakšića 87 23323 Id̄oš Faculty of Science Faculty of Science
Serbia Trg Dositeja Obradovića 4 Trg Dositeja Obradovića 4
goran.pn@gmail.com 21000 Novi Sad 21000 Novi Sad
Serbia Serbia
rackovic@dmi.uns.ac.rs srdjan.skrbic@dmi.uns.ac.rs
ABSTRACT top of standard XML would result in XML containing in-
Standard XML format does not allow for imprecise or incom- sufficiently defined and imprecise information.
plete values. This is one of the requests imposed on this for- Several papers dated to previous decade can be found,
mat by many real-word usages. Using fuzzy logic in order to discussing the use of fuzzy logic in defining XML indefinite-
introduce indefiniteness in XML has been researched in sev- ness. However, the published papers focus mostly on set-
eral different papers in the last decade. While these papers ting up theories and defining syntax. There are only a small
were mostly focused on setting up theories and the syntax, number of papers that deal with the implementation pro-
this paper has practical usage as its main goal. Application cess and practical usage. Some simplistic implementations
called ’Fuzzy XML editor’ was created and described in this were presented, limited to a restricted set of instructions
research. This editor is intended to work with fuzzy XML which often do not meet the needed functionality for any
and to support XSD and DTD schemas. sort of practical use. Without practical usage, it is hard
to get a clear view of actual possibilities of different theo-
ries. Also, the performance and complexity of implementing
Categories and Subject Descriptors seemingly good syntax solutions do not always have to be
H.4.m [Information Systems Applications]: Miscella- satisfactory. In order to overcome these problems, this pa-
neous; D.2.8 [Software Engineering]: Metrics—Complex- per focuses on practical solutions in real-world environment.
ity measures, Performance measures This is achieved by implementing to a level of usable ap-
plications. For numerical computation, MATLAB (Matrix
laboratory) software was used (for the sake of simplicity and
General Terms good performance). MSSQL (Microsoft SQL Server) is used
Theory as underlying database with XQuery queries. Fuzzy priori-
ties and thresholds will be used and implemented in XQuery
Keywords queries for the first time. However, prioritized fuzzy XQuery
is out of scope and will be left for a subsequent paper.
Applications, information sciences, fuzzy databases, infor- Second chapter provides an overview of existing papers,
mation retrieval in the field of fuzzy logic usage with XML. Chapter 3 ex-
plains XML indefiniteness, presenting extended XSD (XML
1. INTRODUCTION Schema Definition) and DTD (Document Type Definition)
XML (Extensible Markup Language) has revolutionized schemas for indefinite XML. The features of application specif-
fields of data storage and transfer in the last decade. There ically developed for this paper are presented in details in
are many positive sides to XML which made it de facto a Chapter 4.
standard for many different uses. Values stored in XML
elements and attributes are absolutely in accordance with 2. RELATED WORK
their definition. Also, the whole structure of XML file is Related research presented in this paper was conducted
predefined and non-changeable. However, in reality, most in the last five years at the University of Novi Sad. The
information comes in the form of imprecise or incomplete main topic was implementation of system capable of using
values (e.g. fast car, tall building). Storing imprecise in- priority fuzzy logic with relational databases. In addition,
formation is not one of the things standard XML supports. complete fuzzy relational database application solution was
Fuzzy sets and fuzzy logic are theories used in many dif- designed and implemented [1, 2, 3].
ferent fields where the use and processing of imprecise and The use of fuzzy logic in indefinite XML is an area where
incomplete information were needed. Adding fuzzy logic on multiple papers have been presented in the last decade. Most
influential research topics are: defining indefiniteness in XML
∗Corresponding author, tel. +381 64 289 8959
values and defining indefiniteness in XML structure.
For defining indefiniteness in XML structure usually XPath
BCI’12, September 16–20, 2012, Novi Sad, Serbia. and XQuery languages were extended by the authors. Pre-
Copyright c 2012 by the paper’s authors. Copying permitted only for private and
sented solutions find elements in XML documents whose po-
academic purposes. This volume is published and copyrighted by its editors.
Local Proceedings also appeared in ISBN 978-86-7031-200-5, Faculty of Sciences,
sitions are not exactly stated. Examples of such solutions
University of Novi Sad. are given in: [4, 5, 6, 7, 8, 9].
58
Most significant form of XML indefiniteness is the indef- from given intervals. The level of membership is taken from
initeness in XML values. For structural definitions of fuzzy the interval [0,1]. Text used to define the value has a stan-
XML documents, XML schemas are usually used. However, dardized format so that parser is able to transform it into the
in some works schema graphs were used for the same pur- corresponding mathematical function. For example, func-
pose. Such examples are presented in: [10, 11, 12, 13, 14, tions are defined as this: A* x + B. Membership will be
15, 16]. set to zero if there are intervals with undefined membership
XML documents are often stored into databases that sup- function.
port XML. Papers related to this subject discuss extending The easiest way to define the previously described fuzzy
database models by introducing fuzzy types or extending the type is to use some of the existing XML schemas. XSD
SQL and XQuery syntax by using fuzzy elements. See more schema which defines the described fuzzy type is presented
on this topic in following papers: [17, 18, 19, 20, 21, 22, 23, below. The element containing function describes part of
24, 25]. the membership function limited by minValue and maxValue
In this paper implementation of indefiniteness in XML constraints. The functions element classifies function parts
values is researched. This assume definition of XML model into a complex membership function. The fuzzy element is a
that allows storing of fuzzy values. The main focus is on the fuzzy set which is defined by a set of membership functions.
implementation of practical fuzzy XML applications. Fuzzy XSD schema is presented in listing 1
3. FUZZY XML SYNTAX Listing 1: XSD schema for fuzzy element
Best solutions presented in related works were combined 1
For instance, [6] describes the most general solution to the 2
problem of storage of fuzzy XML documents. To defined 3
4
constructs in XML element values. The indefiniteness in 5
6
the XML structure was out of scope for this paper and is 7
left for the future work. 8
Membership function is most important when it comes to 9
fuzzy set usage. It is not an easy task to define membership 10
function, while its storage and processing leverage the level 11
of complexity of the implementation. There are two ways 12 < x s : a t t r i b u t e name=”name ” t y p e=” x s : s t r i n g ”/>
of building such solution. The first is that fuzzy set should 13
14
include certain number of simple and well-known function 15
types (e.g. increasing, decreasing, triangular, trapezoidal). 16
In choosing groups of fuzzy sets to implement, one needs 17
18 < x s : e x t e n s i o n b a s e=” x s : s t r i n g ”>
to pay special attention to the choice of sets. The purpose 19 < x s : a t t r i b u t e name=”minValue” t y p e=”
is to cover as many real systems as possible. Still, regard- x s : s t r i n g ” />
less of how many fuzzy sets are introduced, they are still 20 < x s : a t t r i b u t e name=”maxValue ” t y p e=”
x s : s t r i n g ” />
restricted. So, cases whose functions are not described are 21
still unreachable to such solutions. 22
The second option is to define syntax which can model 23
24
the fuzzy set. In this paper, this option was selected due to 25
its versatility. XML is metalanguage, intended to offer ex-
pandability, so there was no need to specifically change XML So, by referencing Fuzzy.xsd schema in a XML document
language syntax to support fuzzy logic. Still, in order to de- and using Fuzzy type for element type, indefinite fuzzy XML
sign XML structure flexible enough to enable defining wide can be written. An example of this is given in listing 2.
variety of fuzzy sets, there are certain conditions. These are
presented below.
Listing 2: Using Fuzzy XSD schema
For example, there is an XML element, , 1
which is undefined and is of a fuzzy type. The element can 2 elements which rep- ” x m l n s : x s=” h t t p : //www . w3 . o r g / 2 0 0 1 /XMLSchema”>
3 < x s : i n c l u d e sc h e m a L o c a t i o n =”Fuzzy . xsd ”/>
resent fuzzy sets. All fuzzy sets are uniquely named using 4
the name attribute, such as . Fuzzy 5
sets are further defined by - membership func- 6
7
tions which can vary in number. Membership functions 8
attributes. As presented here:
maxValue=”10”>; this cannot overlap within a single fuzzy 10
plus infinity, minValue: minus infinity. The value of the 11
element defines the membership function for 12
13
certain area defined by the minValue and maxValue at- 14
tributes. In this value x is a variable that collects values
59
Same can be achieved by using other types of XML schema
documents. Using DTD schema for the same task is pre-
sented in listing 3.
Listing 3: DTD schema for fuzzy element
1
2 < !ELEMENT measurement ( t e m p e r a t u r e )>
3 < !ELEMENT t e m p e r a t u r e ( f u z z y +)>
4 < !ELEMENT f u z z y ( f u n c t i o n +)>
5 < ! ATTLIST f u z z y name CDATA #REQUIRED>
6 < !ELEMENT f u n c t i o n (#PCDATA)>
7 < ! ATTLIST f u n c t i o n
8 minValue CDATA #REQUIRED
9 maxValue CDATA #REQUIRED>
Full example of fuzzy XML documents defined in accor-
dance to presented syntax, storing air temperature measure-
ments are given in listing 4.
Figure 1: Fuzzy XML editor.
Listing 4: Fuzzy XML example
1
2 New s t a t i o n the DTD and XSD models are in charge of working with
3 41 fuzzy XML schemas. The XQuery model implements work-
4 2012−02−03 10 : 3 0
5
ing with fuzzy XQuery, and includes the support for priori-
6 ties and thresholds. However, fuzzy XQuery is out of scope
7 1 of this paper. Each of the components can implement the
8 −1/(Max
−Min ) ∗x + Max/ (Max−Min )
part for working with the fuzzy syntax apart from working
9 with the standard language syntax.
10 The View-Model layer makes it possible to communi-
11 1 / (Max cate with the layer below and consists of several modules.
−Min ) ∗x − Min / (Max−Min )
12 1 The Command group classifies modules for working with
13 commands that implement interfaces for model approach.
14 The Syntax Validation component enables validation of doc-
15
ument syntax. The Fuzzy group enables working with mem-
The value of fuzzy elements can include real text, the so bership functions and fuzzy linguistic variables. The Fuzzy
called linguistic definitions. They start with a # sign. These group relies on the Matlab module which is an interface to
variables are predefined fuzzy sets. Example of such defini- external application - MATLAB. Calculations of the mem-
tion can be found in listing 5. bership level are done using MATLAB libraries.
The View layer is the last layer. It implements the user
interface, so that the user can perform functionalities defined
Listing 5: Linguistic definition example in the Command group. The Main Window component is
1 #Maybe
the main application window which includes the user con-
trols from the Controls group and enables calling of the other
4. FUZZY XML EDITOR independent dialogue windows from the Dialogs group.
Executable version and other data of the application can
Application ’Fuzzy XML editor’ is implemented to demon-
be found at http://www.is.pmf.uns.ac.rs/fuzzydb.
strate practical aspect of working with fuzzy XML syntax.
This application enables creation and working with fuzzy
XML, XSD and DTD documents, and has been developed
specifically for the needs of this paper. Main application 5. CONCLUSION
window is presented on figure 1. This paper successfully unites the process of defining syn-
.NET framework and WPF technology were used in imple- tax and implementing it. An application solution that en-
mentation of this application. Fuzzy XML tool components ables usage of the fuzzy logic constructs with XML data
and their mutual relations are presented in figure 2. has been provided. Users are given a possibility to define
The application consists of several logical modules orga- the arbitrary membership functions, and their computation
nized according to the MVVM (Model View View-Model) is achieved in real time with the usage of the MATLAB
pattern and its principles. software. The practical side of this implementation and its
The Data layer is the lowest level, dealing with the data satisfactory performance has been demonstrated.
storage. The storage options are: text files (file system The presented application solution will be a basis for fur-
component) and database (database component). Microsoft ther development of XML indefiniteness. In future work,
SQL server 2008 R2 support was implemented in order to definition and implementation of the fuzzy XQuery inter-
work with the database. Its potential for working with XML preter that allows the usage of priorities is planned. Also,
is extended by fuzzy elements. the emphasis of future work is on improving the imple-
The Model layer contains several components, where each mented functionalities and the syntax, further improvement
has a task to communicate with certain object types. The of the performance and finally, introduction of indefiniteness
XML model supports working with fuzzy XML objects, while in the XML structure.
60
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