Application of Improved Grey Correlative Method in Safety Evaluation on Fully Mechanized Mining Faces

Transcription

1 Avalable ole at Proceda Earth ad Plaetary Scece 2 ( 2011 ) The Secod Iteratoal Coferece o Mg Egeerg ad Metallurgcal Techology Applcato of Improved Grey Correlatve Method Safety Evaluato o Fully Mechazed Mg Faces CHENG Dog-qua & GU Feg Ata College of Ecoomcs & Maagemet, Shagha Jao Tog Uversty, Shagha , P. R. Cha Abstract The mproved grey correlatve method was put forward order to mprove the objectvty of grey sythetc evaluato method. Because balaced adjacet degree, whch s derved from weghted grey correlatve degree ad balaced degree, was adopted as evaluato crtera ths model, the evaluato result s more adjacet to realty. Ths method was appled the safety evaluato of udergroud trasportato systems 6 st me of Pgdgsha Coal Group Co. Ltd. The safety order preferece ad safety dffereces of all fully mechazed mg faces are gaed. At the same tme, safety problems exstg ma, mache ad evromet of fully mechazed mg faces are poted out. The correspodg coutermeasures to mprove safety are put forward. The evaluato results dcate that the mproved method be more reasoable ad objectve tha geeral grey correlatve method Publshed by Elsever Ltd. Ope Selecto access ad/or uder peer-revew CC BY-NC-ND uder lcese. resposblty of Socety for Resources, Evromet ad Egeerg Keywords: Fully mechazed mg faces, Safety evaluato, Grey correlatve, Balaced adjacet degree; 1. Itroducto Fully mechazed mg has bee the mastream techology coal mg for the sae of ts safety ad hgh effcecy wth the advacemet of scece ad techology. At the same tme, t s also the approach for coalmes to ehace ts output ad ecoomc beeft. However, the udergroud worg face accdets happe frequetly [1], whch has heavly affected safety ad producto coal mes. Safety evaluato s oe of the most mportat measures to promote safety producto coalmes. Amog the quattatve evaluato methods, whether eural etwor [2,3], grey comprehesve evaluato [4,5] or fuzzy sythetc evaluato [6,7] s volved ascertag the weghts of evaluato dces. At preset, methods to ascerta weghts are ether subjectve [2-7] or too complex calculato [8]. Some evaluato methods ca t avod subjectvty essetally, such as to ascerta membershp fucto or membershp degree fuzzy sythetc evaluato. Improved grey correlatve method ca avod defects whch are owed by the above evaluato methods. It s easer to use tha other methods Publshed by Elsever Ltd. do: /j.proeps Ope access uder CC BY-NC-ND lcese.

2 CHENG Dog-qua ad GU Feg / Proceda Earth ad Plaetary Scece 2 ( 2011 ) Improved Grey Correlatve Method 2.1. Etropy ad Etropy Icrease Theorem Suppose a fte dscrete sequece X={x =1,2,,},, x 1 x 1, etropy of sequece X s defed by H( X ) x lx (1) 1 If x =0, let x lx =0. Theorem of etropy crease ca be descrbed as the followg. Let X be a fte dscrete sequece X={x =1,2,...,},, x 1 sequece X to be a costat sequece results the etropy creasg Balaced Degree x 1, H(X) be etropy of sequece X, the ay chage to mae the Etropy s the measure to balaced degree of elemets dscrete sequece X terms of etropy crease theorem. The greater etropy s, the more balaced the dscrete sequece s. For a dscrete sequece wth elemets the maxmum etropy s a costat l whch s oly relevat wth the umber of elemets sequece whe all elemets are equal. Thus, balaced degree of sequece ca be defed by B=H(X)/H m (2) Where H m s the maxmum etropy Weghted Grey Correlatve Degree Grey correlatve degree s the measure to adjacet degree betwee the referece sequece ad relatve sequece. It ca be calculated by grey correlatve coeffcet [9]. The correlatve coeffcet ca be calculated as the followg equato. * * m m v v max max v v L ( ) (3) * * v v max max v v Where s dstgushed coeffcet, t s the rage from 0 to 1. Usually t s 0.5. of the referece sequece. v s the th value of the th relatve sequece. dfferece betwee the referece sequece ad all relatve sequeces. m m v max max v * * v * v s the th value v s the m mum s the maxmum dfferece betwee the referece sequece ad all relatve sequeces. Grey correlatve degree usually ca be expressed as the average of correlatve coeffcets. Dfferece amog all factors was eglected. As a result, the evaluato result may occur larger devatos. The weghted grey correlatve degree ca be expressed as r a L( ) (4) o 1

3 60 CHENG Dog-qua ad GU Feg / Proceda Earth ad Plaetary Scece 2 ( 2011 ) Where r o s weghted grey correlatve degree betwee the referece sequece ad the th relatve sequece. s the etropy weght of the th dex. The process of calculato see also referece [10] Improved Grey Correlatve Method Let E={e =1,,m} be the set of evaluato objects, S={s j j=1,,}be the set of evaluato dces, V={v j =1,,m; j=1,,} be the dces values matrx of evaluato objects, e { v v max v or m v or real deal value} be the deal object whch s composed of evaluato * * * j j j j objects. (l) Ascertag the deal object e * e { v v max v or m v or real deal value} * * * j j j j (2) Pretreatmet of dces values of evaluato objects ad deal object There are may methods for data pretreatmet. The commo lear trasform ca be expressed by V'={v j ' v j '=v j /v j * } (5) (3) Calculatg the dfferece betwee the deal object ad evaluato object C ={c j c j = v j * -v j ' }, Vz. the dfferece of ay evaluato object s a sequece. (4) Calculatg weghted grey correlatve degree Weghted grey correlatve degrees betwee the deal object ad evaluato objects ca be calculated accordg to Eqs. 3 ad 4, tag the deal object as referece sequece ad evaluato objects as relatve sequeces. (5) Mag dfferece sequeces utary The utary sequece ca be expressed as ' ' ' j j j 1 C { c c c / c,j 1,2,, } (6)Calculatg etropy ad balaced degree of sequece C' ' ' ' ' Usg Eq.1, H( C ) cj lcj, Hm l, B H( C)/ Hm. j1 Because grey correlatve degree s the mea value of all weghted correlatve coeffcets, there must be the oretato whch grey correlatve degree s determatve by larger correlatve coeffcets. However, ths oretato ca be avoded usg the balaced degree because the balaced degree s the measure to balaced degree whch evaluato objects are adjacet to the deal object. (7) Calculatg balaced adjacet degree Grey correlatve degree s the measure to adjacet degree betwee sequeces. Balaced degree s the measure to balaced degree of sequece. Therefore balaced adjacet degree ca be obtaed by grey correlatve degree ad balaced degree as the followg equato. w=b r (6) The greater the value of balaced adjacet degree s, the better the evaluato object s. It s more balaced adjacet to deal object tha other evaluato objects. As a result, we ca evaluate every evaluato object va the order preferece of w Improved Mult-level Grey Correlatve Method If the evaluato dces le dfferet levels, we should apply mproved mult-level grey correlatve method. Mult-level evaluato method s smlar to sgle-level evaluato method. The secod-order evaluato results form the frst-order evaluato matrx. The evaluato result matrx ca be obtaed by

4 CHENG Dog-qua ad GU Feg / Proceda Earth ad Plaetary Scece 2 ( 2011 ) weght vector ad the evaluato matrx vew of the sgfcace dfferece of dces the frst level. It ca be expressed by W AW (7) 2 Where W 2 s the balaced adjacet degree matrx. The balaced adjacet degree comes from the secod-order grey evaluato results. 3. Safety Sythetc Evaluato o Fully Mechazed Mg Face Tag the 6 th me of Pgdgsha Coal Group Co. Ltd as a example, mproved grey correlatve method was appled safety evaluato o fully mechazed mg faces Establshg the Set of Evaluato Objects The fully mechazed mg s the ma mg methods ths coal me. The ma am of safety evaluato s to evaluate the safety of the three ma mg faces. Therefore the set of evaluato objects s composed of the three ma mg faces. It ca be expressed as E={e 1, e 2, e 3 }, where e 1 deotes WU mg face, e 2 deotes WU mg face, e 3 deotes WU mg face Establshg the Factor Set There are may factors fluecg the safety of fully mechazed mg face. Accordg to the theory of Ma-Mache-Evromet system egeerg, Ma, mache ad evromet are the prcpal factors. The factor set ca be expressed as U={U 1, U 2, U 3 }={ma, mache, evromet}. These are the frst grade of factors. Each factor s flueced by dfferet factors. These factors are the 2 d grade of factors. These factors ca be expressed as U 1 ={average age, average legth of servce, average legth of educato, average professoal trag tme, cotraveto rate}, U 2 ={perfect rate, rate for mateace, falure rate, updatg rate, rate of worg sc, qualfed rate of safeguard}, U 3 ={temperature, humdty, yawp, llumato, gas desty}. The orgal data are show table 1. Table 1 Orgal data of ma, mache ad evromet fully mechazed mg faces huma mache Evaluato average average average average cotraveto perfect rate for falure objects legth of legth of professoal age/a rate /% rate /% mateace/% rate /% servce /a educato /a trag tme /d e e e (Cotue) mache evromet updatg rate/% rate of worg sc/% qualfed rate of safeguard /% temperature / humdty /% yawp /db llumato /lx gas desty /% Because there are so may evaluato dces, the mult-level evaluato model should be adopted. At frst the secod-grade dces were evaluated, fally the frst-grade dces were evaluated.

5 62 CHENG Dog-qua ad GU Feg / Proceda Earth ad Plaetary Scece 2 ( 2011 ) Secod-order sythetc evaluato The process of secod-order sythetc evaluato was show as follows tag ma as a example. (1) Ascertag the deal object Amog the ma s dces, average age above 25 ad cotraveto rate are cost dces. The others are proftable dces. Hece the deal object s e * 1 =(25, 7, 10, 120, 40%). (2) Pre-treatmet of dces values of evaluato objects ad deal object Accordg to Eq.5, pre-treated data of ma ca be expressed as follows V (3) Calculatg the dfferece betwee the deal object ad evaluato objects The dfferece betwee the deal object ad evaluato objects ca be calculated as C ={c j c j = v * j - v j ' }. The dfferece matrx, whch cossts of dfferece sequeces of all evaluato objects, ca be expressed by C (4) Calculatg weghted grey correlatve degree The deal object s referece sequece. Evaluato objects are relatve sequeces. Weghted grey correlatve degree ca be calculated accordg to Eq.3 ad Eq.4. R={0.867, 0.744, 0.502}. (5) Mag dfferece sequeces of evaluato objects utary The utary matrx of dfferece betwee the deal object ad evaluato objects ca be expressed as follows accordg to Eq.6. C (6) Calculatg etropy ad balaced degree of sequece C ' The balaced degree of sequece ca be calculated accordg to Eqs.1 ad 2 as: B 1 =0.946, B 2 =0.940, B 3 = (7) Calculatg balaced adjacet degree The balaced adjacet degree betwee evaluato objects ad the deal object ca be calculated by Eq.7. The results ca be expressed as: w 11 =0.820, w 12 =0.699, w 13 = Smlarly, we ca evaluate mache ad evromet. The procedure of calculato s omtted. The evaluato result of mache s w 21 =0.402, w 22 =0.356, w 23 = The evaluato result of evromet s w 31 =0.097, w 32 =0.182, w 33 = Frst-order sythetc evaluato The evaluato matrx the frst-order evaluato s composed of the evaluato results the secodorder evaluato. The weghts of the frst-order factors are ascertaed by the method of AHP(the Aalytcal Herarchy Process). The weght vector s A={0.682, 0.103, 0.215}. Accordg to Eq.7, the evaluato result ca be expressed as follows.

6 CHENG Dog-qua ad GU Feg / Proceda Earth ad Plaetary Scece 2 ( 2011 ) W AW Accordg to evaluato crtera, the order preferece s e 1 e 2 e 3. Accordg to secod-order evaluato results, the dffereces of these mg faces safety of huma, mache ad evromet ca be got easly. Therefore, the correspodg coutermeasures to mprove ts safety ca be draw out. 4. Coclusos Safety evaluato o fully mechazed mg faces s oe of the most mportat coutermeasures to mprove safety producto. The mproved grey correlatve method put forward ths artcle s advacemet for evaluato methods. Balaced degree was ascertaed accordg to etropy theory. Weghted grey correlatve degree was sytheszed by grey correlatve coeffcets ad etropy weghts. Balaced adjacet degree, whch was ascertaed by balaced degree ad weghted grey correlatve degree, was tae as evaluato crtera ths method. Ths ca avod subjectvty durg assessmet. At the same tme, ths method ca t be used to evaluatg sgle object. It ca oly be used to gettg the order preferece of evaluato objects. Therefore, ths method stll eeds to be mproved further. Refereces [1]State Admstrato of Wor Safety Domestc Safety producto Cha. [2]Gratto, P.M., Verdes, P.F., Ceccatto, H.A. Neural etwor esembles: evaluato of aggregato algorthms[j]. Artfcal Itellgece, 2005, 163(2): [3]Zhag Yuayua, Yag Shsog, Dog Peg. The costructo of dex system ad comprehesve evaluato model based o mproved geetc algorthm ad fuzzy eural etwor[j]. Appled Mechacs ad Materals, 2010, 20-23: [4]Wu Q, Zhou W, L S. Applcato of grey umercal model to groudwater resource evaluato[j]. Evrometal Geology, 2005, 47(7): [5]Wag Da-Ng, Zhao Mg, Zhao Hog-B. Sythetc evaluato of water qualty water supply etwors based o grey classfed model[j]. Joural of Chogqg Jazhu Uversty, 2007, 29(6): [6]Ketata Chef, Rocwell Mara C. Fuzzy evaluato of stream sample relablty[j]. Meral Processg ad Extractve Metallurgy Revew, 2006, 27(4): [7]ZHOU Xao-te, HE Xag-lag, XIAO Hua-sha, et al. Comprehesve evaluato of me area surface subsdece by applcato of fuzzy sythetc evaluato[j]. Safety ad Evrometal Egeerg, 2009, 16(5): [8]Yurdaul, Mustafa. AHP approach the credt evaluato of the maufacturg frms Turey[J]. Iteratoal Joural of Producto Ecoomcs,2004, 88(3): [9]L-yu WU & Yu-zhog YANG. Improved Grey Correlatve Method for Rs Assessmet o Coal ad Gas Outburst[A].Proceedgs of 2011 Iteratoal Coferece ocomputer ad Maagemet (CAMAN), [10]YU-ZHONG YANG, LI-YUN WU. Improved Grey Correlatve Method for Gree Vedor Selecto Coal Group[A].Proceedgs of Iteratoal Coferece o Iteret Techology ad Applcatos