Cover for Volume.13, No.2
text
article
2016
eng
Iranian Journal of Fuzzy Systems
University of Sistan and Baluchestan
1735-0654
13
v.
2
no.
2016
0
http://ijfs.usb.ac.ir/article_2629_01f14615681aca7b51d39c6611ee7c7b.pdf
dx.doi.org/10.22111/ijfs.2016.2629
Fuzzy multi-criteria decision making method based on fuzzy structured element with incomplete weight information
Xinfan
Wang
School of Science, Hunan University of Technology, Zhuzhou, Hunan,
412007, China
author
Jianqiang
Wang
School of Business, Central South University, Changsha, Hunan,
410083, China
author
Xiaohong
Chen
School of Business, Central South University, Changsha, Hunan,
410083, China
author
text
article
2016
eng
The fuzzy structured element (FSE) theory is a very useful toolfor dealing with fuzzy multi-criteria decision making (MCDM)problems by transforming the criterion value vectors of eachalternative into the corresponding criterion function vectors. Inthis paper, some concepts related to function vectors are firstdefined, such as the inner product of two function vectors, thecosine of the included angle between two function vectors and theprojection of a function vector on another. Then a method based onFSE is developed to solve fuzzy MCDM problems in which thecriterion values take the form of general bounded closed fuzzynumbers and the criterion weight information is incompletecertain. In this method, the projections of criterion functionvectors on the fuzzy ideal function point (FIFP) are used to rankall the alternatives and then select the most desirable one, andan optimization model is constructed to determine the weights ofcriteria according to the incomplete weight information. Finally,an example is given to illustrate the feasibility andeffectiveness of the developed method.
Iranian Journal of Fuzzy Systems
University of Sistan and Baluchestan
1735-0654
13
v.
2
no.
2016
1
17
http://ijfs.usb.ac.ir/article_2356_5a40d370d70c87597df91b924bd8af47.pdf
dx.doi.org/10.22111/ijfs.2016.2356
A NEW APPROACH BASED ON OPTIMIZATION OF RATIO FOR SEASONAL FUZZY TIME SERIES
Ufuk
Yolcu
Department of Statistics, Faculty of Science, Ankara University, 06100
Ankara, Turkey
author
text
article
2016
eng
In recent years, many studies have been done on forecasting fuzzy time series. First-order fuzzy time series forecasting methods with first-order lagged variables and high-order fuzzy time series forecasting methods with consecutive lagged variables constitute the considerable part of these studies. However, these methods are not effective in forecasting fuzzy time series which contain seasonal structures. In this respect, it would be more appropriate to use methods that consider the seasonal relations in seasonal fuzzy time series forecasting. Although seasonal fuzzy time series forecasting methods exist in literature, these methods use equal interval lengths in partition of the universe of discourse. This situation incapacitates the performance of the method in forecasting time series including seasonality and trend. In this study, a new fuzzy time series forecasting method in which intervals constituting partition of the universe of discourse increase in time at a rate that obtained based on optimization was proposed. The proposed method was applied to two real time series and obtained results were compared with other methods and the superior performance of the proposed method was proved.
Iranian Journal of Fuzzy Systems
University of Sistan and Baluchestan
1735-0654
13
v.
2
no.
2016
19
36
http://ijfs.usb.ac.ir/article_2357_6875b4f9aecc564feec951e7b3ddb660.pdf
dx.doi.org/10.22111/ijfs.2016.2357
A Hybrid Multi-attribute Group Decision Making Method Based on Grey Linguistic 2-tuple
Congjun
Rao
School of Science, Wuhan University of Technology, Wuhan 430070,
P. R. China
author
Junjun
Zheng
School of Economics and Management, Wuhan University, Wuhan
430072, P. R. China
author
Cheng
Wang
School of Mathematics and Economics, Hubei University of Education,
Wuhan 430072, P. R. China
author
Xinping
Xiao
School of Science, Wuhan University of Technology, Wuhan 430070,
P. R. China
author
text
article
2016
eng
Because of the complexity of decision-making environment, the uncertainty of fuzziness and the uncertainty of grey maybe coexist in the problems of multi-attribute group decision making. In this paper, we study the problems of multi-attribute group decision making with hybrid grey attribute data (the precise values, interval numbers and linguistic fuzzy variables coexist, and each attribute value has a certain grey degree), and present a new grey hybrid multi-attribute group decision making method based on grey linguistic 2-tuple. Concretely, the concept of grey linguistic 2-tuple is defined based on the traditional linguistic 2-tuple, and the transformation methods of transforming the precise values, interval numbers and linguistic fuzzy variables into the grey linguistic 2-tuples are presented respectively. Further, a new grey linguistic 2-tuple weighted averaging (emph{GLTWA}) operator is presented to aggregate multiple decision makers' individual decision information into comprehensive decision information, and then a ranking method based on grey 2-tuple correlation degree is presented to rank all alternatives and to select the winners. An application decision making example of supplier selection is also given to validate the method developed and to highlight the implementation, practicality and effectiveness of the presented method.
Iranian Journal of Fuzzy Systems
University of Sistan and Baluchestan
1735-0654
13
v.
2
no.
2016
37
59
http://ijfs.usb.ac.ir/article_2358_921ff0008ea7f62892c5003e6baad75f.pdf
dx.doi.org/10.22111/ijfs.2016.2358
A FUZZY-BASED SPEED CONTROLLER FOR IMPROVEMENT OF INDUCTION MOTOR'S DRIVE PERFORMANCE
H.
Asgharpour-Alamdari
Department of Electrical Engineering, Semnan University, Semnan, Iran
author
Y.
Alinejad-Beromi
Department of Electrical Engineering, Semnan University, Semnan, Iran
author
H.
Yaghobi
Department of Electrical Engineering, Semnan University, Semnan, Iran
author
text
article
2016
eng
Induction motors (IMs) are widely used in many industrial applications due to their robustness, low cost, simplicity and relative good efficiency. One of the major considerations for IMs is their speed control. PI (proportional-integrator) controllers are usually used as speed controller. Adjusting the gain of PI controller is time-consuming which needs thorough considerations. Hence, fuzzy controllers are proposed to overcome such problems. In this paper, firstly drive of a three-phase induction motor is designed based on PI controller and then fuzzy logic controller is implemented. This paper presents a novel speed control technique based on fuzzy logic with two inputs and one output for drive of an IM. The inputs are speed error and derivation of speed error and the output is speed. Finally comparison is done between the PI and fuzzy controllers which shows superiority of the fuzzy controller over PI controller.
Iranian Journal of Fuzzy Systems
University of Sistan and Baluchestan
1735-0654
13
v.
2
no.
2016
61
70
http://ijfs.usb.ac.ir/article_2359_d0c6ddbaed27b7b597713095ad41c16e.pdf
dx.doi.org/10.22111/ijfs.2016.2359
Alternating Regular Tree Grammars in the Framework of Lattice-Valued Logic
Maryam
Ghorani
Faculty of Mathematical Sciences, Shahrood University of Technology, Shahrood, Iran
author
Mohammad Mehdi
Zahedi
Department of Mathematics, Graduate University of Advanced Technology, Kerman, Iran
author
text
article
2016
eng
In this paper, two different ways of introducing alternation for lattice-valued (referred to as {L}valued) regular tree grammars and {L}valued top-down tree automata are compared. One is the way which defines the alternating regular tree grammar, i.e., alternation is governed by the non-terminals of the grammar and the other is the way which combines state with alternation. The first way is taken over to prove a main theorem: the class of languages generated by an {L}valued alternating regular tree grammar {LAG}) is equal to the class of languages accepted by an {L}valued alternating top-down tree automaton {LAA}). The second way is taken over to define a new type of automaton by combining the {L}valued alternating top-down tree automaton with stack, called {L}-valued alternating stack tree automaton {LASA} and the generative power of it is compared to some well-known language classes, especially to {LAA} and to {LAG}Also, we have derived a characterization of the state alternating regular tree grammar {LSAG}) in terms of {LASA}.
Iranian Journal of Fuzzy Systems
University of Sistan and Baluchestan
1735-0654
13
v.
2
no.
2016
71
94
http://ijfs.usb.ac.ir/article_2360_9a374f39abaa600423ce805945586dd1.pdf
dx.doi.org/10.22111/ijfs.2016.2360
Algebraic Properties of Intuitionistic Fuzzy Residuated Lattices
Farnaz
Ghanavizi Maroof
Department of Mathematics, Faculty of Mathematics and
Compute, Shahid Bahonar University of Kerman, 76169-14111, Kerman, Iran
author
Esfandiar
Eslami
Department of Mathematics, Faculty of Mathematics and Com-
pute, Shahid Bahonar University of Kerman, 76169-14111, Kerman, Iran
author
text
article
2016
eng
In this paper, we investigate more relations between the symmetric residuated lattices $L$ with their corresponding intuitionistic fuzzy residuated lattice $tilde{L}$. It is shown that some algebraic structures of $L$ such as Heyting algebra, Glivenko residuated lattice and strict residuated lattice are preserved for $tilde{L}$. Examples are given for those structures that do not remain the same. Also some special subsets of $tilde{L}$ such as regular elements $Rg(tilde{L})$, dense elements $D(tilde{L})$, infinitesimal elements $Inf(tilde{L})$, boolean elements $B(tilde{L})$ and $Rad_{BL}(tilde{L})$ are characterized. The relations between these and corresponding sets in $L$ will be investigated.
Iranian Journal of Fuzzy Systems
University of Sistan and Baluchestan
1735-0654
13
v.
2
no.
2016
95
109
http://ijfs.usb.ac.ir/article_2361_a03406f1388de5728fafa2ef1c358332.pdf
dx.doi.org/10.22111/ijfs.2016.2361
Width invariant approximation of fuzzy numbers
Alireza
Khastan
Department of Mathematics, Institute for Advanced Studies in
Basic Sciences, Zanjan, Iran
author
Zahra
Moradi
Department of Mathematics, Institute for Advanced Studies in Basic
Sciences, Zanjan, Iran
author
text
article
2016
eng
In this paper, we consider the width invariant trapezoidal and triangularapproximations of fuzzy numbers. The presented methods avoid the effortful computation of Karush-Kuhn-Tucker Theorem. Some properties of the new approximation methods are presented and the applicability of the methods is illustrated by examples. In addition, we show that the proposed approximations of fuzzy numbers preserve the expected value too.
Iranian Journal of Fuzzy Systems
University of Sistan and Baluchestan
1735-0654
13
v.
2
no.
2016
111
130
http://ijfs.usb.ac.ir/article_2362_b6a4f056d6dc711eada410b16ef83211.pdf
dx.doi.org/10.22111/ijfs.2016.2362
Irreducibility on General Fuzzy Automata
Mohammad
Horry
Shahid Chamran University of Kerman, Kerman, Iran
author
text
article
2016
eng
The aim of this paper is the study of a covering of a max-mingeneral fuzzy automaton by another, admissible relations, admissiblepartitions of a max-min general fuzzy automaton,$tilde{delta}$-orthogonality of admissible partitions, irreduciblemax-min general fuzzy automata. Then we obtain the relationshipsbetween them.
Iranian Journal of Fuzzy Systems
University of Sistan and Baluchestan
1735-0654
13
v.
2
no.
2016
131
144
http://ijfs.usb.ac.ir/article_2363_d9fe18c52e5072bf681626d5f67c6ab5.pdf
dx.doi.org/10.22111/ijfs.2016.2363
On metric spaces induced by fuzzy metric spaces
D.
Qiu
College of Mathematics and Physics,, Chongqing University of Posts and
Telecommunications,, Nanan, Chongqing, 400065, P. R. China
author
R.
Dong
College of Mathematics and Physics,, Chongqing University of Posts and
Telecommunications,, Nanan, Chongqing, 400065, P. R. China
author
H.
Li
College of Mathematics and Physics,, Chongqing University of Posts and
Telecommunications,, Nanan, Chongqing, 400065, P. R. China
author
text
article
2016
eng
For a class of fuzzy metric spaces (in the sense of George and Veeramani) with an H-type t-norm, we present a method to construct a metric on a fuzzy metric space. The induced metric space shares many important properties with the given fuzzy metric space. Specifically, they generate the same topology, and have the same completeness. Our results can give the constructive proofs to some problems for fuzzy metric spaces in the literature, which are shown by examples in this paper.
Iranian Journal of Fuzzy Systems
University of Sistan and Baluchestan
1735-0654
13
v.
2
no.
2016
145
160
http://ijfs.usb.ac.ir/article_2364_95750b4afd0e7c65b341f7f2c7bce7d7.pdf
dx.doi.org/10.22111/ijfs.2016.2364
Persian-translation vol.13, no.2
text
article
2016
eng
Iranian Journal of Fuzzy Systems
University of Sistan and Baluchestan
1735-0654
13
v.
2
no.
2016
162
171
http://ijfs.usb.ac.ir/article_2630_64fcd74af2b71ca479d7c69999b15d9a.pdf
dx.doi.org/10.22111/ijfs.2016.2630