Shahram Shariati - Mining method selection by using an integrated model.pdf

Embed Size (px)

Citation preview

  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    1/16

    International Research Journal of Applied and Basic Sciences 2013 Available online at www.irjabs.comISSN 2251-838X / Vol, 6 (2):199-214Science Explorer Publications

    Mining method selection by using an integrated

    model

    Shahram Shariati1,Abdolreza Yazdani-Chamzini2, Behrang Pourghaffari Bashari3

    1. Department of geology, Sari branch, Islamic Azad University, Sari, Iran.

    2. Young Researchers Club, South Tehran Branch, Islamic Azad University, Tehran, Iran.

    3. Mining Department, South Tehran Branch, Islamic Azad University, Tehran, Iran.

    CorrespondingAuthor email:[email protected], [email protected] and

    [email protected], [email protected] and [email protected]

    ABSTRACT: The problem of mining method selection is one of the most important decisions that

    should be made by mining managers and engineers. Selecting a proper underground mining method

    to accomplish extraction from a mineral deposit is very significant in terms of the economics, safety

    and the productivity of mining operations. The aim objective of this paper is to develop an integrated

    model to selection the best mining method by using effective criteria and at the same time, taking

    subjective judgments of decision makers into account. Proposed model is based on fuzzy analytic

    hierarchy process (FAHP)methodology and technique for order preference by similarity to ideal

    solution (TOPSIS). FAHP is appliedtodetermine the weights of the evaluation criteria for mining

    method selection that these weights are inserted to the TOPSIS technique to rank the alternatives

    and select the most appropriate alternative. The proposed method is applied for AngouranMine in Iranand finally the optimum mining methods forthis mine are ranked. The study was followed by the

    sensitivity analysis of the results.

    Keywords:Mining method selection, MCDM, FAHP, TOPSIS

    INTRODUCTION

    Selection of mining method is one of the most crucial decisions in the design stage of mine that mining

    engineers have to make. Selecting a mining method for mineral resources is completely dependent on the

    uncertain geometrical and geological characteristic of the resource (Azadeh et al, 2010). It is necessary to the

    unique characteristics of each mineral resource be taken into account in order to select the suitable mining

    method for the extraction of a certain resource, so that the utilized method would have the maximum

    technical-operational congruence with the geological and geometrical conditions of the mineral resource. To

    make the right decision on mining method selection, all effective criteria related to the problem should be taken

    into account. Increasing the number of the evaluation criteria in decision making problem makes the problem

    more complex, but also the rightness of the decision increases. Therefore, there is a need for alternative

    methods, which can consider all known criteria related to underground mining method selection in the decision

    making process (Alpay, Yavuz, 2009). The sensitivity of this decision has led to different solutions introduced by

    different researchers (Boshkov et al, 1973; Morrison, 1976; Laubscher, 1981; Nicholas, 1981; Hartman, 1982;

    mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]
  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    2/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    200

    Brady, Brown, 1985; Hartman, 1987; Adler, Thompson, 1897, Miller-Tait et al, 1995).

    In the above-mentioned studies, mining method selection procedure has been looked from qualitative

    viewpoint (Azadeh et al, 2010). Likewise two of the problems of these approaches is lack of having correct

    relation between represent classes of parameters especially in near the boundary conditions and having the

    same relevance of all evaluation criteria. Therefore, these studies were neither enough nor complete, as it is not

    possible to design a methodology that will automatically choose a mining method for the ore body studies

    (Bitarafan, Ataei, 2004).

    The merit of using multi-criteria decision making (MCDM) methods is their ability to solve complex and multi

    criteria problems by handling both quantitative and qualitative criteria. The MCDM methods arestrong tools for

    determining the best alternative among a pool of the feasible alternatives.Technique for Order Preference by

    Similarity to Ideal Solution (TOPSIS) is one common MCDM method that takes into consider the ideal and the

    anti-ideal solutions simultaneously. This technique is applied by different researches because of being rational,

    simple computations, and results are obtained in shorter time than other methods such as AHP (analytical

    hierarchy process) and ANP (analytic network process) (Fouladgar et al, 2011; Lashgari et al, 2011).

    On the other hand, AHP is widely used to calculate the weights of evaluation criteria. This method use

    pair-wise comparison for obtaining the relative weights of criteria. AHP is strongly connected to human judgmentand pairwise comparisons in AHP may cause evaluators assessment bias which makes the comparison

    judgment matrix inconsistent (Aydogan, 2011). Therefore, fuzzy analytical hierarchy process (FAHP) is

    employed to solve the bias problem in AHP.

    The main aim of this paper is to develop an integrated model based on FAHP and TOPSIS methods in

    order to evaluate mining methods and select the best alternative in the Anguran mine.TOPSIS is employed to

    select a mining method and the FAHP is applied to calculate criteria weights.

    The rest of this paper is organized as follows. In section 2, a brief review of fuzzy theory is presented,

    including fuzzy sets, fuzzy numbers, and linguistic variables. Section 3 illustrates the FAHP methodology for

    calculating the relative weights of evaluation criteria. The procedure of the TOPSIS method is described in

    section 4. The proposed model is presented in section 5. Section 6 presents an empirical study of miningmethod selection. A sensitivity analysis is conducted in section 7. Finally, concluding remarks are discussed in

    section 8.

    Fuzzy logic

    Fuzzy logic, introduced by Zadeh (1965), is a powerful tool for facing with the existing uncertainty, imprecise

    knowledge, and less of information. Fuzzy numbers may be of almost any shape (though conventionally they are

    required to be convex and to have finite area), but frequently they will be triangular (piecewise linear), s-shape

    (piecewise quadratic) or normal (bell shaped) (Kelemenis et al. 2011).

    A triangular fuzzy number (TFN) is defined as ( , , )A a b c ; which a, b, and c are crisp numbers and a b c .

    A fuzzy number is defined by its membership function whose values can be any number in the interval [0,

    1].Assume that TFNs start rising from zero atx=a; reach a maximum of 1 at x = b; and decline to zero at x = c as

    shown in Figure 1. Then the membership function )A

    x of a TFN is given by

    (1)

    0 ,

    ( ) / ( ) ,)

    ( ) / ( ) ,

    0 ,

    A

    x a

    x a b a a x bx

    x c b c b x c

    x c

  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    3/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    201

    Figure 1. Triangular fuzzy number

    Let1 1 1( , , )a a b c and 2 2 2( , , )b a b c be twoTFNs then the vertex method is defined to compute the

    distance between them by Eq. (2):

    (2)

    2 2 2

    1 2 1 2 1 2

    1( , ) ( ) ( ) ( )

    3d a b a a b b c c

    Fuzzy AHP

    Analytical hierarchy process (AHP),introduced by Saaty (1980),is a popular MCDM method that

    decomposes a sophisticated problem into a hierarchy. The elements of hierarchy levelsarecompared in pairs

    toassesstheirrelativepreferencewithrespecttoeachof the elementsatthenexthigher level (Singh & Benyoucef,

    2011). The AHP is widely employed for tackling multi-criteria decision making problems in real world applications.

    However, in many practical cases the human preference model is uncertain and evaluator might be reluctant orunable to assign crisp values to the comparison judgments (Chan & Kumar, 2007). The merit of using a fuzzy

    approach is to determine the relative importance of attributes using fuzzy numbers instead of precise numbers

    (nt, Soner, 2008; Sun, Lin, 2009; Sun, 2010; Kara, 2011).There are many fuzzy AHP methods proposed on

    the basis ofthe concepts of the fuzzy set theory and hierarchical structure.

    In this study, we use Changs extent analysis method (Chang, 1996) due to its computational simplicity and

    effectiveness.

    Let X = {x1, x2, , xn} be an object set and U = {u1, u2, , um} be a goal set. According to the method of Changs

    extent analysis, each object is taken and extent analysis for each goal, gi, is performed, respectively. Therefore,

    m extent analysis values for each object can be obtained, with the following signs:

    1 2

    , , ..., , 1, 2, ..., .m

    gi gi giM M M i n Where all the ( 1, 2, ... , )j

    giM j m are TFNs.The procedure of Changs extent analysis is defined in the following steps:

    Step 1- The value of fuzzy synthetic extent with respect to ith object is calculated as:

    (3)

    1

    1 1 1

    m n mj j

    i gi gi

    j i j

    S M M

    ca

    x

    A)

    A x

  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    4/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    202

    To obtain m j

    gij iM

    , perform the fuzzy addition operation of m extent analysis values for a particular matrix suchthat

    (4)

    1 1 1 1

    , ,m m m mj

    gi i i i

    j j j j

    M l m u

    And to obtain1

    1 1

    n m j

    gii jM

    , perform the fuzzy addition operation of ( 1, 2, ... , )

    j

    giM j m values

    such that

    (5)

    1 1 1 1 1

    , ,n m n n n

    j

    gi i i i

    i j i i i

    M l m u

    And then calculate the inverse of the vector in Eq. (6) such that

    (6)1

    1 11 1 1

    1 1 1, ,

    n mj

    gi n n nn j i i ii i i

    Mu m l

    Step 2- The degree of possibility of2 2 2 2 1 1 1 1( , , ) ( , , )M l m u M l m u is assigned as

    (7)

    2 1 1 2( ) sup [min( ( ), ( ))]M My x

    V M M x y

    And can be equivalently expressed as follows:

    (8)

    2 1

    2 1 1 2 2 1 2

    1 2

    2 2 1 1

    1, if

    ( ) ( ) ( ) 0, if

    , otherwise( ) ( )

    M

    m m

    V M M hgt M M d l u

    l u

    m u m l

    Both the values of1 2( )V M M and 2 1( )V M M are needed to compare M1and M2.

    Step 3- The degree of possibility for a convex fuzzy number to be greater than k convex fuzzy numbers Mi( i=1,

    2, , k ) can be computed by

    (9)

    1 2 1 2( , , ... , ) [( ) and ( ) and ... and ( )]

    min ( ), i=1, 2, ... , k

    k k

    i

    V M M M M V M M M M M M

    V M M

    Assume that

    (10)

    ( ) min ( )i i kd A V S S

  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    5/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    203

    For k = 1, 2, ,n; k i .Then the weight vector is obtained by

    (15)

    1 2( ( ), ( ), ..., ( ))T

    nW d A d A d A

    WhereAi(i=1, 2, , n) are n elements.

    Step 4- The normalized weight vectors are resulted through normalization

    (11)

    1 2( ( ), ( ), ..., ( ))T

    nW d A d A d A

    Where W is a non-fuzzy number.

    TOPSIS technique

    The Technique for Order Preference by Similarity to Ideal Solution(TOPSIS) was first introduced by Hwang

    and Yoon (1981). TOPSIS method is based on the concept that the most appropriate alternative should have the

    shortest distance from the positive ideal solution (PIS)and the farthest distance from the negative ideal solution(NIS). PIS minimize the cost criteria and maximize the benefit criteria, whereas the NIS minimizes the benefit

    criteria and maximizes the cost criteria (Kelemenis et al. 2011). There have been plenty of studies related with

    the TOPSIS method in the literature (Parkan & Wu, 1999; Gamberini et al. 2006; Yu et al. 2009;Chen et al. 2009;

    Antucheviieneet al. 2010;Tupenaite et al. 2010;Chang et al. 2010). The major steps of the TOPSIS can be

    described as follows:

    Step 1. Construct the decision matrix.

    To calculate the performance of a set of alternatives on a given set of criteria, the decision matrix of mn

    dimension is formed, which m and n are the number of alternatives and criteria respectively.

    Step 2. Calculate the normalized decision matrix. The normalized value rijis calculated as

    (12)

    2

    1

    , 1,..., ; 1,...,m

    ij ij ij

    j

    r f f j m i n

    Step 3. Calculate the weighted normalized decision matrix.

    We can compute the weighted normalized decision matrix by considering the relative importance of evaluation

    criteria as

    (13)

    [ ]ij m nV v

    and

    (14)

    ij ij jv r w

    Where : 1,2,...,jW w j n normalized criteria weights.

    Step 4. Identify positive ideal (A*) and negative ideal (A-) solutions. The positive ideal solution and the

    negative-ideal solution are shown in Eqs. (15), (16).

    (15)

    http://www.tandfonline.com/action/doSearch?action=runSearch&type=advanced&result=true&prevSearch=%2Bauthorsfield%3A%28Antuchevi%C4%8Diene%2C+Jurgita%29http://www.tandfonline.com/action/doSearch?action=runSearch&type=advanced&result=true&prevSearch=%2Bauthorsfield%3A%28Antuchevi%C4%8Diene%2C+Jurgita%29http://www.tandfonline.com/action/doSearch?action=runSearch&type=advanced&result=true&prevSearch=%2Bauthorsfield%3A%28Antuchevi%C4%8Diene%2C+Jurgita%29
  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    6/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    204

    1 2 3( , , ,..., ) max ( 1, 2,..., )n iji

    A v v v v v i n

    (16)

    1 2 3( , , ,..., ) min ( 1, 2,..., )n iji

    A v v v v v i n

    Step 5. Calculate separation measures. The distance of each alternative from A * and A- can be currently

    calculated using Eqs. (17), (18).

    (17)

    1

    ( , ) , 1,2,...,n

    i ij j

    j

    d d v v i m

    (18)

    1

    ( , ) , 1,2,...,n

    i ij j

    j

    d d v v i m

    Step 6. Calculate the similarities to ideal solution. This step solves the similarities to an ideal solution by Eq.(19).

    (19)

    ii

    i

    dCC

    d d

    Step 7. Rank preference order. Choose an alternative with maximumiCC or rank alternatives according to

    iCC in descending order.

    The proposed model

    The proposed model for evaluating the underground mining methods in Angouran mine, contained of FAHP

    and TOPSISmethods, comprises of three main steps: (1) determine the main and sub evaluation criteria; (2)

    calculate the relative weights of criteria byFAHP and (3) evaluate the possible alternatives by TOPSIS and finally

    select the optimum alternative among a pool of alternatives. Schematic diagram of the proposed model for

    mining method selection is depicted in Figure2.

    In the step 1, after defining the problem, the feasible mining methods for the extraction process of the ore

    are identified. Next, the effective criteria of possible alternatives are determined. In the final phase of the step 1,

    the decision hierarchy is structured such that the goal is in the first level, evaluation criteria are in the second

    level, sub-criteria are in the third level, and possible alternatives are on the last level. In the step 2, after

    constructing the decision hierarchy, the relative weights of the evaluation criteria are obtained by using the FAHP

    technique. Based on these evaluation criteria, the required data in order to form the pairwise comparison matrix

    are collected from experts knowledge. In the step 3, the performance ratings of the feasible alternatives

    corresponding to the evaluation criteria are assigned by applying the UBC technique. Finally,TOPSIS is applied

    to evaluate the alternatives and select the best underground mining method among a pool of alternatives.

    An empirical application

    The purpose of the empirical application is to illustrate the use of the suggested method. Angouran ZnPb

  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    7/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    205

    deposit is located in the western Zanjan province about 450 km northwest of Tehran (Figure3a). This deposit is

    one of the major zinc producers in Iran, a country with approximately 11 mil lion tons of zinc metal constituent.

    Angouran has 16 million tons of ore with a zinc concentration of 26% and a lead concentration of 6% 1. This

    deposit is close to the Urumieh-Dokhtar Magmatic Arc, which issituated within one of a number of metamorphic

    inlier complexes in the central Sanandaj-Sirjan Zone of the Zagros orogenic belt (Gilg et al, 2005). A

    metamorphic core complex surrounds the Angouran deposit, which comprises amphibolites, serpentinites,

    gneisses, micaschists, and various, mainly calcitic and rarely dolomitic marbles. Some of the geological

    specifications of the area are represented in Figure 3b.

    Figure2. Schematic diagram of the proposed model

    1www.turquoisepartners.com

    Define the problem

    Identify feasible alternatives

    Form decision making team

    Assign the main and sub-criteria

    Calculate the weight of criteria

    Evaluate the possible alternatives

    Determine the final rank

    Select the best mining method

    Step 3:

    Construct the decision hierarchy

    Form pairwise comparison matrix

    Form the decision matrix

    Step 1:Decision

    Step 2:

    http://en.wikipedia.org/wiki/Zinchttp://en.wikipedia.org/wiki/Zinchttp://en.wikipedia.org/wiki/Zinc
  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    8/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    206

    Determine the main and sub-criteria

    The evaluation criteria should be determined that cover the requirements connected with the mining

    method selection problem. According to the UBC technique, the proposed set of criteria consists of eleven

    parameters. The main characteristics of the parameters are Ore body thickness(C1), Ore body dip (C2), Ore

    body shape(C3), grade distribution (C4), Ore body depth(C5), Ore body RSS2 (C6), Footwall RSS (C7),

    Hanging wall RSS (C8), Ore body RMR3 (C9), Footwall RMR (C10), and Hanging wall RMR(C11).

    Figure 3. Geography of Angouran mine (a) and schematic regional geological map of the area (b) (Boni et al, 2007)

    As a result, these eleven criteria were employed in the process of the evaluation and decision hierarchy is

    established accordingly as depicted in Figure4. The hierarchy of mining method selection can be divided into

    three levels: level 1 includes the main goal of the hierarchy, which is selection the most optimum mining

    method.The criteria are on the second level. Level 3 comprises the feasible alternatives determined by the

    decision maker team, including Block Caving (A1), Sublevel Stoping (A2), Sublevel Caving (A3), Cut & Fill

    (A4),Top Slicing (A5), and Square Set Stoping (A6).

    The Angouran ore body is located in the crest of an open anticlinal structure within the metamorphic

    basement that plunges eastward at 1020 (Gilg et al, 2005). This ore body is some 600 m long in

    2Rock Substance strength3Rock mass rating

  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    9/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    207

    Northern-Southern line and 200400 m across. The ore body is delimited by two major NNW-SSEand NW-SE

    trending faults and a third NE-SW fault (Boni et al, 2007).

    In Angouran mine, extraction of deposit has been started from near surface by open pit mining and it has

    continued to the level of 2880 meters. According to increasing the extraction depth and environmental

    requirements, mine is designed to transfer from open pit to underground mining. For this reason, underground

    mining method should be selected; so that, the evaluation criteria under consideration be satisfied.

    Figure4. Decision hierarchy

    Calculate the relative weights of criteria by FAHP

    After building the hierarchical structure, we designed an AHP questionnaire format and arrange the

    pair-wise comparisons matrix. Firstly each decision maker individually carry out pair-wise comparison by using

    Saatys 19 scale (Saaty,1980) as shown in Table 1.The consistency of the decision makers judgments during

    the evaluation phase is calculated by consistency ratio (CR) that cloud be defined as follows (Aguaron et al,

    2003):

    (20)

    max

    1

    nCR

    n

    where ax is the principal eigenvalue and n is the rank of judgment matrix. The closer the inconsistency ratio to

    zero, the greater the consistency (Torfi et al, 2010). The resulting CR values for our case study are smaller than

    the critical value of 0.1, this show that there is no evidence of inconsistency.

    A1 A2 A3 A4 A5 A6

    Selecting the most appropriate mining method

    C1

    C2

    C3

    C4

    C5

    C7

    C8

    C9

    C10

    C11

    C6

  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    10/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    208

    Table 1. Pair-wise comparison scale (Saaty, 1980)

    Option Numerical value(s)

    Equal 1

    Marginally strong 3

    Strong 5

    Very strong 7

    Extremely strong 9

    Intermediate values to reflect fuzzy inputs 2, 4, 6, 8

    Reflecting dominance of second alternative compared with the

    first

    reciprocals

    The importance weights of the criteria determined by fifteen decision-makers that are obtained through Eq.

    (21) are presented in Table 5.

    (21)

    ij ij ij ij( , , )x l m u

    k k

    ij ij ij ij ij

    1

    1min{ }, , max{ }

    k

    ij

    k

    l x m x u xk

    Whereijx is the fuzzy importance weights of each criterion that are determined by all experts, xij is the crisp

    weight of each criterion, k is the number of expert (here, k is equal to 15).

    The results derived from the computations according to the final fuzzy matrices provided in Tables 2 are

    presented inTables3.The weight calculation details by using FAHP are given below.

    Table 2. Pairwise comparison matrix

    C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11

    C1 (1,1,1) (0.14,0.24,0.5) (0.33,0.98,2) (0.25,0.76,2) (0.25,0.56,1) (0.33,0.98,3) (0.25,1.04,2) (0.25,0.56,2) (0.2,0.73,3) (0.25,0.63,2) (1,1.82,3)

    C2 (2,4.16,7) (1,1,1) (5,6.23,8) (4,6.43,9) (4,5.34,8) (4,5.78,9) (5,6.87,9) (4,6.12,8) (5,7.13,9) (3,4.76,8) (5,7.54,9)

    C3 (0.5,1.02,3.0) (0.12,0.16,0.2) (1,1,1) (0.2,0.67,2) (0.25,0.74,1) (0.5,1.23,3) (0.33,0.87,1) (0.5,0.96,2) (0.50,1.21,3) (0.33,0.54,1) (0 .5,1.12,3)

    C4 (0.5,1.32,4) (0.11,0.16,0.25) (0.5,1.49,5) (1,1,1) (0.14,0.36,0.5) (0.33,0.63,1) (0.2,0.46,1) (0.33,0.65,2) (0.33,1.11,2) (0.2,0.35,1) (0.5,1.34,3)

    C5 (1,1.79,4) (0 .12,0.19,0.25) (1,1.35,4) (2,2.78,7) (1,1,1) (2,3.78,5) (4,5.67,8) (1,2.46,4) (2,2.56,4) (0.17,0.37,2) (1,3.12,5)

    C6 (0.33,1.02,3) (0.11,0.17,0.25) (0.33,0.81,2) (1,1.59,3) (0.2,0.26,0.5) (1,1,1) (3,4.78,7) (0.33,0.89,2) (1,2.23,4) (0.14,0.27,0.5) (2,3.67,5)

    C7 (0.5,0.96,4) (0.11,0.15,0.2) (1,1.15,3) (1,2.17,5) (0.12,0.17,0.25) (0.14,0.21,0.33) (1,1,1) (0.2,0.27,0.5) (0.25,0.98,3) (0.2,0.45,1) (0.5,1.23,2)

    C8 (0.5,1.79,4) (0.12,0.16,0.25) (0.5,1.04,2) (0.5,1.54,3) (0.25,0.41,1) (0.5,1.12,3) (2,3.7,5) (1,1,1) (0.5,2.31,4) (0.25,0.78,2) (0.5,2.45,4)

    C9 (0.33,1.37,5) (0.11,0.14,0.2) (0.33,0.83,2) (0.5,0.90,3) (0.25,0.39,0.5) (0.25,0.45,1) (0.33,1.02,4) (0.25,0.43,2) (1,1,1) (0.33,0.91,3) (1,2.31,4)

    C10 (0.5,1.59,4) (0.12,0.21,0.33) (1,1.85,3) (1,2.86,5) (0.5,2.7,6) (2,3.7,7) (1,2.22,5) (0.5,1.28,4) (0.33,1.09,3) (1,1,1) (0.5,1.45,3)

    C11 (0.33,0.55,1) (0.11,0.13,0.2) (0.33,0.89,2) (0.33,0.75,2) (0.2,0.32,1) (0.2,0.27,0.5) (0.5,0.81,2) (0.25,0.41,2) (0.25,0.43,1) (0.33,0.69,2) (1,1,1)

    The value of fuzzy synthetic extent with respect to the ith object is calculated as

    1 (4.26,9.3, 21.5) (0.003,0.005,0.009) (0.012,0.048,0.198)S

    2 (42,61.37,85) (0.003,0.005,0.009) (0.12,0.32,0.783)S

  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    11/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    209

    3 (4.74,9.52,20.23) (0.003,0.005,0.009) (0.013,0.05,0.186)S

    4 (4.15,8.86,20.75) (0.003,0.005,0.009) (0.012,0.046,0.191)S

    5 (15.29,25.06,44.25) (0.003,0.005,0.009) (0.044,0.131,0.408)S

    6 (9.45,16.69, 28.25) (0.003,0.005,0.009) (0.027,0.087,0.26)S

    7 (5.03,8.74,20.28) (0.003,0.005,0.009) (0.014,0.046,0.187)S

    8 (6.62,16.3, 29.25) (0.003,0.005,0.009) (0.019,0.085,0.269)S

    9 (4.69,9.74,25.7) (0.003,0.005, 0.009) (0.013,0.051,0.237)S

    10(8.45,19.96, 41.33) (0.003,0.005,0.009) (0.024,0.104,0.381)S

    11 (3.84,6.25,14.7) (0.003,0.005,0.009) (0.011,0.033,0.135)S

    Table 3. V values result

    1S 2S 3S 4S 5S 6S 7S 8S 9S 10S 11S

    1( )V S 0.224 0.994 1 0.653 0.816 1 0.83 0.987 0.758 1

    2( )V S 1 1 1 1 1 1 1 1 1 1

    3( )V S 1 0.198 1 0.638 0.81 1 0.826 0.993 0.75 1

    4( )V S 0.987 0.207 0.981 0.636 0.801 1 0.816 0.975 0.74 1

    5( )V S 1 0.604 1 1 1 1 1 1 1 1

    6( )V S 1 0.377 1 1 0.833 1 1 1 0.93 1

    7( )V S 0.98 0.197 0.977 0.997 0.628 0.794 0.81 0.971 0.736 1

    8( )V S 1 0.39 1 1 0.832 0.992 1 1 0.928 1

    9( )V S 1 0.303 1 1 0.708 0.85 1 0.864 0.8 1

    10( )V S 1 0.548 1 1 0.927 1 1 1 1 1

    11( )V S 0.886 0.052 0.878 0.901 0.484 0.67 0.903 0.69 0.87 0.609

  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    12/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    210

    Then priority weights are computed by using Eq. (9):

    ( 1) min(0.224,0.994,1,0.653,0.816,1,0.83,0.987, 0.758,1) 0.224d C

    ( 2) min(1,1,1,1,1,1,1,1,1,1) 1d C

    ( 3) min(1,0.198,1,0.638,0.81,1,0.826,0.993,0.75,1) 0.198d C ( 4) min(0.987,0.207,0.981,0.636,0.801,1,0.816,0.975,0.74,1) 0.207d C

    ( 5) min(1,0.604,1,1,1,1,1,1,1,1) 0.604d C

    ( 6) min(1,0.377,1,1,0.833,1,1,1,0.93,1) 0.377d C

    ( 7) min(0.98,0.197,0.977,0.997,0.628,0.794,0.81,0.971, 0.736,1) 0.197d C

    ( 8) min(1,0.39,1,1,0.832,0.992,1,1, 0.928,1) 0.39d C

    ( 9) min(1,0.303,1,1,0.708,0.85,1,0.864,0.8,1) 0.303d C ( 10) min(1,0.548,1,1, 0.927,1,1,1,1,1) 0.548d C

    ( 11) min(0.886,0.052,0.878,0.901,0.484,0.67, 0.903,0.69,0.87,0.609) 0.052d C

    \Priorityweightsform (0.224,1,0.198,0.207,0.604,0.377,0.197,0.39,0.303,0.548,0.052)W vector. After

    the normalization of these values priority weights respect to main goal are calculated as (0.055, 0.244, 0.048,

    0.051, 0.147, 0.092, 0.048, 0.095, 0.074, 0.134, 0.013). Mentioned priority weights have indicated for each

    criterion in Table 4. The results of the FAHP analysis for relative weights of the evaluation criteria are

    summarized in Figure5.

    Table 4. Priority weights for criteria

    Criteria Local weights Global weights

    C1 0.224 0.055

    C2 1 0.244

    C3 0.198 0.048

    C4 0.207 0.051

    C5 0.604 0.147C6 0.377 0.092

    C7 0.197 0.048

    C8 0.39 0.095

    C9 0.303 0.074

    C10 0.548 0.134

    C11 0.052 0.013

  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    13/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    211

    Figure 5. Relative weights of cr iteria

    Determine the final rank and select the best alternative by TOPSIS

    In this step, evaluation matrices are established by fifteen decision makers for evaluating theunderground

    mining methods under different criteria based onthe UBC technique.In this study,all criteria are benefit criteria;

    thus the higher the score, the better the performance of the mining methodis. The performance ratings of mining

    methods with respect to each criterion are determined by using the UBC technique and the results are

    presented in Table 5.

    Table 5. Performance ratings of alternatives

    C11C10C9C8C7C6C5C4C3C2C1

    33210022423A1

    23435434314A2

    33321232314A3

    24222323131A4

    12112021122A5

    01100011030A6

    Table 6. Weighted decision matrix

    C11C10C9C8C7C6C5C4C3C2C1

    0.00740.05780.02500.02180.00000.00000.05290.01710.03220.09220.0242A1

    0.00490.05780.05000.06540.04120.06820.07930.03420.02420.04610.0323A2

    0.00740.05780.03750.04360.00820.03410.07930.01710.02420.04610.0323A3

    0.00490.07710.02500.04360.01650.05120.05290.02560.00810.13830.0081A4

    0.00250.03860.01250.02180.01650.00000.05290.00850.00810.09220.0161A5

    0.00000.01930.01250.00000.00000.00000.02640.00850.00000.13830.0000A6

    After forming the weighted decision matrix, the positive-ideal solution (PIS, A*) and the negative-idealsolution (PIS, A-) are derived. Finally, alternatives are ranked in descending order as presented in Table 7.

    According to CCivalues, the ranking of the alternatives in descending order are A4, A2, A3, A1, A6and A5. The

    proposed model indicates that Cut & Fill (A4) is the best method with CC value of 0.819. Rankings of the

    alternatives according to CCivalues are depicted in Figure6.

    After forming the evaluation matrix, the second phase is to calculate the normalized decision matrix by

    using Eq. (14).Next, using the criteria weights obtained by FAHP, the weighted decision matrix is derived as

    presented in Table 6.

    Table 7. TOPSIS results

    id

    id iCC Rank

    A1 0.012433 0.006694 0.350 4

    A2 0.008942 0.018628 0.676 2

    A3 0.01211 0.009794 0.447 3

    A4 0.003951 0.017937 0.819 1

    A5 0.014413 0.004274 0.229 6

    A6 0.020971 0.008499 0.288 5

  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    14/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    212

    Figure 6. Final rank of alternatives

    Sensitivity analysis

    In order to identify the cause of the difference in the outcome of the proposed model, a sensitivity analysis is

    conducted. This technique generates different scenarios that may change the priority of alternatives and be

    needed to reach a consensus. If the ranking order be changed by increasing or decreasing the importance of the

    criteria, the results are expressed to be sensitive otherwiseit is robust. In this study, sensitivity analysis is

    implemented to see how sensitive the alternatives change with the importance of the criteria. This tool graphical

    exposes the importance of criteria weights in selecting the optimal alternative among the feasible alternatives.

    The main goal of sensitivity analysis is to see which criteria is most significant in influencing the decision making

    process. For this reason, eleven experiments were conducted that each experiment is generated by an increase

    of 20% in the amount of the weight of the criterion under consideration.

    It can be seen from Fig. 7 that alternative A4 has the highest score in all experiments.Therefore, it can be

    resulted that the decision making process isnot sensitive to the criteria weight with alternative A4(Cut & Fill)

    emerging as the winner.

    Figure7. Sensitivity analysis

    CONCLUSION

    The process of mining method selection is a methodology for evaluating the proper alternatives and

    selecting the best alternative with respect to criteria under consideration. The main goal of this study is to

    evaluate the feasible alternatives and select the most appropriate candidate among a pool of alternatives by

  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    15/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    213

    using theMCDM methods. According to the complex structure of the problem,inaccurate and imprecise data,

    less of information, and inherent uncertainty, the usage of the fuzzy sets can be useful.

    In this paper, an integrated model based on FAHP and TOPSIS is developed. FAHP based on the extent

    analysis technique is applied to obtain weights of the evaluation criteria, while TOPSIS is utilized to prioritize the

    feasible alternatives. The weights derived from FAHP are involved in the problem of the mining method selection

    by using them in TOPSIS calculations and ranking order is determined based on these weights. Finally, the

    alternative with the highest score is selected. Also, sensitivity analysis was conducted to determine the influence

    of criteria weights on the problem of the mining method selection. The strength of the proposed model is the

    ability to evaluate and rank alternatives under partial or lack of quantitative information.

    ACKNOWLEDGEMENT

    The authors would like to acknowledge the financial support of Ayerma International Industrial and Mining

    Research Company for this research.

    REFERENCES

    Adler L, Thompson SD.1992. Mining method classification systems, SME Mining Engineering Handbook, Society for Mining Engineering,

    Metallurgy and Exploration, Inc. pp. 531-537.

    Aguaron J, Escobar MT, Moreno-Jimenez JM.2003. Consistency stability intervals for ajudgment in AHP decision support system.European

    Journal of Operational Research 145: 382393.doi:10.1016/S0377-2217(02)00544-1

    Alpay S, Yavuz M.2009. Underground mining method selection by decision making tools. Tunnelling and Underground Space Technology 24:

    173-184.doi:10.1016/j.tust.2008.07.003

    Antucheviiene J,Zavadskas EK, Zakareviius A.2010. Multiple criteria construction management decisions considering relations between

    criteria. Technological and Economic Development of Economy 16(1): 109-125. doi:10.3846/tede.2010.07

    Aydogan EK.2011. Performance measurement model for Turkish aviation firms using the rough-AHP and TOPSIS methods under fuzzy

    environment. Expert Systems with Applications 38(4): 3992-3998.doi:10.1016/j.eswa.2010.09.060

    Azadeh A, Osanloo M, Ataei M.2010. A new approach to mining method selection based on modifying the Nicholas technique. Applied Soft

    Computing 10: 1040-1061.doi:10.1016/j.asoc.2009.09.002

    Bitarafan MR, Ataei M.2004. Mining method selection by multiple criteria decision making tools, The Journal of The South African Institute of

    Mining and Metallurgy, pp. 493-498. Available at http://www.saimm.co.za/Journal/v107n02p137.pdf

    Boni M, Gilg HA, Balassone G, Schneider J, Allen CR, Moore F.2007. HypogeneZn carbonate ores in the Angouran deposit, NW Iran. Miner

    Deposita 42:799-820.doi:10.1007/s00126-007-0144-4

    Boshkov SH, Wright FD.1973. Basic and parametric criteria in the selection, design and development of underground mining systems. SME

    Mining Engineering Handbook. SME-AIME, New York.

    Brady BHG, Brown ET.1985.Rock mechanics for underground mining. London: George Allen and Unwin.

    Chan FTS, Kumar N.2007. Global supplier development considering risk factors using fuzzy extended AHP-based approach. Omega 35:

    417-431.doi: 10.1016/j.omega.2005.08.004

    Chang ChH, Lin JJ, Lin JH, Chiang MCh.2010. Domestic open-end equity mutual fund performance evaluation using extended TOPSIS

    method with different distance approaches. Expert Systems with Applications 37(6): 4642-4649.doi:10.1016/j.eswa.2009.12.044

    Chang DY.1996. Applications of the extent analysis method on fuzzy AHP. European Journal of Operational Research 95:

    649-655.doi:10.1016/0377-2217(95)00300-2

    Chen MSh, Lin MCh, Wang ChCh, Chang CA.2009. UsingHCA and TOPSIS approaches in personal digital assistant menuicon interface

    design. International Journal of Industrial Ergonomics 39(5): 689-702.doi:10.1016/j.ergon.2009.01.010

    http://dx.doi.org/10.1016/j.tust.2008.07.003http://www.tandfonline.com/action/doSearch?action=runSearch&type=advanced&result=true&prevSearch=%2Bauthorsfield%3A%28Zavadskas%2C+Edmundas+Kazimieras%29http://dx.doi.org/10.1016/j.tust.2008.07.003http://www.tandfonline.com/action/doSearch?action=runSearch&type=advanced&result=true&prevSearch=%2Bauthorsfield%3A%28Zakarevi%C4%8Dius%2C+Algimantas%29http://dx.doi.org/10.1016/j.tust.2008.07.003http://www.tandfonline.com/action/doSearch?action=runSearch&type=advanced&result=true&prevSearch=%2Bauthorsfield%3A%28Antuchevi%C4%8Diene%2C+Jurgita%29http://www.tandfonline.com/action/doSearch?action=runSearch&type=advanced&result=true&prevSearch=%2Bauthorsfield%3A%28Zavadskas%2C+Edmundas+Kazimieras%29http://www.tandfonline.com/action/doSearch?action=runSearch&type=advanced&result=true&prevSearch=%2Bauthorsfield%3A%28Zakarevi%C4%8Dius%2C+Algimantas%29http://www.tandfonline.com/loi/tted20?open=16http://www.tandfonline.com/toc/tted20/16/1http://dx.doi.org/10.1016/j.eswa.2010.09.060http://dx.doi.org/10.1016/j.eswa.2010.09.060http://dx.doi.org/10.1016/j.asoc.2009.09.002http://dx.doi.org/10.1016/j.asoc.2009.09.002http://dx.doi.org/10.1007/s00126-007-0144-4http://dx.doi.org/10.1007/s00126-007-0144-4http://dx.doi.org/10.1016/j.omega.2005.08.004http://dx.doi.org/10.1016/j.omega.2005.08.004http://dx.doi.org/10.1016/j.eswa.2009.12.044http://dx.doi.org/10.1016/j.ergon.2009.01.010http://www.sciencedirect.com/science/article/pii/S0169814109000109?_alid=1825280784&_rdoc=8&_fmt=high&_origin=search&_docanchor=&_ct=191&_zone=rslt_list_item&md5=02421b1f698026240bcc367ff99468dahttp://www.sciencedirect.com/science/article/pii/S0169814109000109?_alid=1825280784&_rdoc=8&_fmt=high&_origin=search&_docanchor=&_ct=191&_zone=rslt_list_item&md5=02421b1f698026240bcc367ff99468dahttp://dx.doi.org/10.1016/0377-2217%2895%2900300-2http://dx.doi.org/10.1016/j.eswa.2009.12.044http://dx.doi.org/10.1016/j.omega.2005.08.004http://dx.doi.org/10.1007/s00126-007-0144-4http://dx.doi.org/10.1016/j.asoc.2009.09.002http://dx.doi.org/10.1016/j.eswa.2010.09.060http://www.tandfonline.com/toc/tted20/16/1http://www.tandfonline.com/loi/tted20?open=16http://www.tandfonline.com/action/doSearch?action=runSearch&type=advanced&result=true&prevSearch=%2Bauthorsfield%3A%28Zakarevi%C4%8Dius%2C+Algimantas%29http://www.tandfonline.com/action/doSearch?action=runSearch&type=advanced&result=true&prevSearch=%2Bauthorsfield%3A%28Zavadskas%2C+Edmundas+Kazimieras%29http://www.tandfonline.com/action/doSearch?action=runSearch&type=advanced&result=true&prevSearch=%2Bauthorsfield%3A%28Antuchevi%C4%8Diene%2C+Jurgita%29http://dx.doi.org/10.1016/j.tust.2008.07.003
  • 8/10/2019 Shahram Shariati - Mining method selection by using an integrated model.pdf

    16/16

    Intl. Res. J. Appl. Basic. Sci. Vol., 6 (2), 199-214, 2013

    214

    Fouladgar MM, Yazdani-Chamzini A, Zavadskas EK.2011. An integrated model for prioritizing strategies of the Iranian mining

    sector.Technological and Economic Development of Economy 17(3): 459-483.doi:10.3846/20294913.2011.603173

    Gamberini R, Grassi A, Rimini B.2006. A new multi-objective heuristic algorithm for solving the stochastic assembly line re-balancing

    problem. International Journal of Production Economics 102(2): 226-243.doi:10.1080/00207540802176046

    Gilg HA, Boni M, Balassone G, Allen CR, Banks D, Moore F.2005. Marble-hosted sulfide ores in the Angouran Zn-(PbAg) deposit, NW Iran:

    interaction of sedimentary brines with a metamorphic core complex. Miner Depos 31(1):116. doi:10.1007/s00126-005-0035-5

    Hartman HL.1987. Introductory Mining Engineering. John Wiley, New Jersey.

    Hartman HL.1992. Introduction to Mining. SME Mining Engineering Handbook (2nd Edition), Society for Mining, Metallurgy, and Exploration,

    Inc. Littleton, Colorado, pp. 1-4.

    Hwang CL, Yoon K.1981. Multiple attributes decision making methods and applications. Berlin: Springer.

    Kara SS. 2011. Supplier selection with an integrated methodology in unknown environment. Expert Systems with Applications 38(3):

    2133-2139.doi:10.1016/j.eswa.2010.10.044

    Kelemenis A, Ergazakis K, Askounis D.2011. Support managers selection using an extension of fuzzy TOPSIS. Expert Systems with

    Applications 38: 2774-2782. :doi:10.1016/j.eswa.2010.08.068

    Lashgari A, Fouladgar MM, Yazdani-Chamzini A, Skibniewski MJ.2011. Using an integrated model for shaft sinking method selection.

    Journal of CivilEngineering and Management 17(4): 569580.doi:10.3846/13923730.2011.628687

    Laubscher DH.1981. Selection of Mass Underground Mining Methods. Design and Operation of Caving and Sublevel Stoping Mines.

    SME-AIME, New York.

    Miller-Tait L, Panalkis R, Poulin R.1995. UBC mining method selection. In: Proceeding of the Mine Planning and Equipment Selection

    Symposium, pp. 163168.

    Morrison RGK.1976. AW Philosophy of Ground Control. McGill University, Montreal, Canada.

    Nicholas DE.1981. Method Selection A Numerical Approach. Design and Operation of Caving and Sublevel Stoping Mines. SME-AIME,

    New York.

    nt S, Soner S.2008. Transshipment site selection using the AHP and TOPSIS approaches under fuzzy environment. Waste Management

    28(9): 1552-1559.doi:10.1016/j.wasman.2007.05.019

    Parkan C, Wu ML.1999. Decision-making and performance measurement models with applications to robot sele ction. Computers &

    Industrial Engineering 36(3): 503-523.doi:10.1016/S0360-8352(99)00146-1

    Saaty TL.1980. The Analytic Hierarchy Process. McGraw-Hill, Pittsburgh.

    Singh RK, Benyoucef L.2011. A fuzzy TOPSIS based approach for e-sourcing. Engineering Applications of Artificial Intelligence 24: 437-448.

    doi:10.1016/j.engappai.2010.09.006

    Sun ChCh, Lin GTR. 2009. Using fuzzy TOPSIS method for evaluating the competitive advantages of shopping websites. Expert Systems

    with Applications 36(9): 11764-11771.doi:10.1016/j.eswa.2009.04.017

    Sun ChCh. 2010. A performance evaluation model by integrating fuzzy AHP and fuzzy TOPSIS methods. Expert Systems with Applications

    37(12):7745-7754.doi:10.1016/j.eswa.2010.04.066

    Torfi F, Farahani RZ, Rezapour Sh.2010. Fuzzy AHP to determine the relative weights of evaluat ion criteria and Fuzzy TOPSIS to rank the

    alternatives. Applied Soft Computing 10(2): 520-528.doi:10.1016/j.asoc.2009.08.021

    Tupenaite L, Zavadskas EK, Kaklauskas A, Turskis Z, Seniut M.2010. Multiple criteria assessment of alternatives for built and human

    environment renovation. Journal of Civil Engineering and Management 16(2): 257-266.doi:10.3846/jcem.2010.30

    Yu L, Shen X, Pan Y, Wu Y.2009. Scholarly journal evaluation based on panel data analysis. Journal of Informetrics 3(4):

    312-320.doi:10.1016/j.joi.2009.04.003

    Zadeh LA.1965. Fuzzy sets. Information and Control 8 (3): 338353.doi:10.1016/S0019-9958(65)90241-X

    http://dx.doi.org/10.1016/j.eswa.2010.10.044http://www.sciencedirect.com/science/journal/09574174http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235635%232011%23999619996%232568736%23FLA%23&_cdi=5635&_pubType=J&view=c&_auth=y&_acct=C000228598&_version=1&_urlVersion=0&_userid=10&md5=cdaa827eb13942f363a68f7489dad7c3http://www.sciencedirect.com/science/journal/09574174http://dx.doi.org/10.1016/j.eswa.2010.10.044http://dx.doi.org/10.1016/j.eswa.2010.08.068http://dx.doi.org/10.1016/j.eswa.2010.08.068http://www.sciencedirect.com/science/journal/0956053Xhttp://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%236017%232008%23999719990%23693346%23FLA%23&_cdi=6017&_pubType=J&view=c&_auth=y&_acct=C000228598&_version=1&_urlVersion=0&_userid=10&md5=d130e85a1cef87bd4f19eb335931229fhttp://www.sciencedirect.com/science/journal/0956053Xhttp://dx.doi.org/10.1016/j.wasman.2007.05.019http://dx.doi.org/10.1016/S0360-8352%2899%2900146-1http://dx.doi.org/10.1016/S0360-8352%2899%2900146-1http://dx.doi.org/10.1016/j.engappai.2010.09.006http://www.sciencedirect.com/science/journal/09574174http://dx.doi.org/10.1016/j.engappai.2010.09.006http://www.sciencedirect.com/science/journal/09574174http://www.sciencedirect.com/science/journal/09574174http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235635%232009%23999639990%231211063%23FLA%23&_cdi=5635&_pubType=J&view=c&_auth=y&_acct=C000228598&_version=1&_urlVersion=0&_userid=10&md5=d4a454092a1b990857413ef8d8dc548chttp://www.sciencedirect.com/science/journal/09574174http://dx.doi.org/10.1016/j.eswa.2009.04.017http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235635%232010%23999629987%232259763%23FLA%23&_cdi=5635&_pubType=J&view=c&_auth=y&_acct=C000228598&_version=1&_urlVersion=0&_userid=10&md5=beb1953c56f8a3ee670ea463e98e7ef2http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235635%232009%23999639990%231211063%23FLA%23&_cdi=5635&_pubType=J&view=c&_auth=y&_acct=C000228598&_version=1&_urlVersion=0&_userid=10&md5=d4a454092a1b990857413ef8d8dc548chttp://dx.doi.org/10.1016/j.eswa.2009.04.017http://www.sciencedirect.com/science/journal/09574174http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235635%232010%23999629987%232259763%23FLA%23&_cdi=5635&_pubType=J&view=c&_auth=y&_acct=C000228598&_version=1&_urlVersion=0&_userid=10&md5=beb1953c56f8a3ee670ea463e98e7ef2http://dx.doi.org/10.1016/j.eswa.2010.04.066http://dx.doi.org/10.1016/j.eswa.2010.04.066http://dx.doi.org/10.1016/j.asoc.2009.08.021http://dx.doi.org/10.1016/j.asoc.2009.08.021http://www.sciencedirect.com/science/article/pii/S1751157709000352?_alid=1825280784&_rdoc=15&_fmt=high&_origin=search&_docanchor=&_ct=191&_zone=rslt_list_item&md5=a68c505399f63ce002372d6f9cbc88d9http://dx.doi.org/10.1016/j.joi.2009.04.003http://www.sciencedirect.com/science/article/pii/S1751157709000352?_alid=1825280784&_rdoc=15&_fmt=high&_origin=search&_docanchor=&_ct=191&_zone=rslt_list_item&md5=a68c505399f63ce002372d6f9cbc88d9http://dx.doi.org/10.1016/j.asoc.2009.08.021http://dx.doi.org/10.1016/j.eswa.2010.04.066http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235635%232010%23999629987%232259763%23FLA%23&_cdi=5635&_pubType=J&view=c&_auth=y&_acct=C000228598&_version=1&_urlVersion=0&_userid=10&md5=beb1953c56f8a3ee670ea463e98e7ef2http://www.sciencedirect.com/science/journal/09574174http://www.sciencedirect.com/science/journal/09574174http://dx.doi.org/10.1016/j.eswa.2009.04.017http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235635%232009%23999639990%231211063%23FLA%23&_cdi=5635&_pubType=J&view=c&_auth=y&_acct=C000228598&_version=1&_urlVersion=0&_userid=10&md5=d4a454092a1b990857413ef8d8dc548chttp://www.sciencedirect.com/science/journal/09574174http://www.sciencedirect.com/science/journal/09574174http://www.sciencedirect.com/science/journal/09574174http://dx.doi.org/10.1016/j.engappai.2010.09.006http://dx.doi.org/10.1016/S0360-8352%2899%2900146-1http://dx.doi.org/10.1016/j.wasman.2007.05.019http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%236017%232008%23999719990%23693346%23FLA%23&_cdi=6017&_pubType=J&view=c&_auth=y&_acct=C000228598&_version=1&_urlVersion=0&_userid=10&md5=d130e85a1cef87bd4f19eb335931229fhttp://www.sciencedirect.com/science/journal/0956053Xhttp://www.sciencedirect.com/science/journal/0956053Xhttp://dx.doi.org/10.1016/j.eswa.2010.08.068http://dx.doi.org/10.1016/j.eswa.2010.10.044http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235635%232011%23999619996%232568736%23FLA%23&_cdi=5635&_pubType=J&view=c&_auth=y&_acct=C000228598&_version=1&_urlVersion=0&_userid=10&md5=cdaa827eb13942f363a68f7489dad7c3http://www.sciencedirect.com/science/journal/09574174