www.ijape.org Iteratioal Joural of Automatio ad Power Egieerig (IJAPE) Volume 2 Issue 2, February 2013 Hazard Idetificaito of Railway Sigalig System Usig PHA ad HAZOP Methods Jog Gyu Hwag *1, Hyu Jeog Jo 2 O demad Trasit Research Team, Korea Railroad Research Istitute, Uiwag si, Gyeoggi do, Sout Korea *1 jghwa@krri.re.kr; 2 hjjo@krri.re.kr Abstract Railway sigalig system requires the high level of safety sice these have to esure safe operatio of the trai. Accordig to these reaso, safety related regulatios for railway sigalig systems are iteratioally stadardized. To secure the safety required by iteratioal stadards, the hazard cotrol is ecessary with system lifecycle, ad the hazard idetificatio is eeded to hazard cotrol. To draw this hazard which is the basis of whole hazard cotrol, there are very may techiques such as PHL(Prelimiary Hazard List), PHA(Prelimiary Hazard Aalysis), HAZOP, FMEA(Failure Mode Effect Aalysis), etc. i the activities ad methods. The PHA ad HAZOP method is recommeded for hazard aalysis at IEC stadards, but this method has several usuitable problems to apply to railway sigalig system. I this paper we recommed the modified HAZOP method, which would be suitable for aalyzig safety of the railway sigalig systems. Ad also a example of PHA ad this method applied to real system is also icluded. Keywords RailwaySigalig System; PHA; HAZOP Itroductio The electroic ad computerized railway sigalig systems have replaced the existig mechaical systems, resultig i itelliget ad automatic highperformace systems. For the existig electrical ad mechaical systems, empirical approaches ad egieerʹs ituitio are maily used to idetify ay faults, assurig a certai degree of safety i the railway sigalig systems. However, the ew computerized railway sigalig systems do ot allow the safety assurace based o such empirical approaches to detect faults. Therefore, IEC (Iteratioal Electrotechical Commissio) requires more rigorous safety activities to assure the safety i the railway sigalig systems[iec 61508, 1998][IEC 62278, 2002] [IEC 62425, 2005]. To secure the safety required by iteratioal stadards, the hazard cotrol i accordace with the system life cycle is ecessary. This hazard cotrol activity is cosisted of various stages such as hazard idetificatio stage, hazard risk assessmet stage, hazard risk cotrol stage, etc. reflectig them to the desig o the basis of results of this hazard ad risk aalysis. To draw the hazard which is the basis of whole hazard activities amog these various stages, the applicatio of PHA ad HAZOP method is highly recommeded (HR: Highly Recommed) for the hazard aalysis o railway system i the IEC 62425, which is the iteratioal stadard. I additio, these two methods are highly recommeded by the Yellow Book also which correspods to the guidelie to safety activities of British railway system[railtrack, 2000]. Amog these two techiques, PHA is methods to idetify the early stage hazard, ad the HAZOP are used as detailed methods to draw hazards based o the hazard draw at the early stage. The HAZOP techique is the formalized techology to draw the hazard, ad there are cases where HAZOP methods were applied i some precedig studies i Korea to draw the hazard of railway sigalig systems. However, sice HAZOP method which was stadardized iteratioally[iec 61882, 2001][Redmill, 1997] has bee iitially desiged ad developed i the chemical plat idustry, its effect ad efficiecy of applicatio are declied due to the elemets ot suitable for applyig existig parameters ad guide words to railway sigalig systems as they are[sirivasa, 1998][M.U.h, 2001][Vekat, 2000], E.Habibi]. Therefore, this paper proposed parameters ad guide words possible to be applied to the hazard aalysis of railway sigalig system effectively while maitaiig existig HAZOP method, ad it was amed as HAZOP R(HAZOP for Railway Sigalig) i this paper[krri, 2011][J.G.Hwag,2010]. The hazard idetificatio is the basic activity i hazard maagemet procedure. It is impossible to delete or mitigate of hazards i system developmet lifecycle, if the hazards were ot idetified. This paper studied 32
Iteratioal Joural of Automatio ad Power Egieerig (IJAPE) Volume 2 Issue 2, February 2013 www.ijape.org applicatio techology of PHA method to draw the iitial hazard which is the most fudametal stage ad HAZOP R method to the railway sigalig systems to idetify cocretely the iitial hazards. Ad also the results of cosequece aalysis o idetified hazards by ETA (Evet Tree Aalysis) were represeted. PHA are methods to idetify the early stage hazard, ad the FMEA ad HAZOP are used as detailed methods to draw hazards based o the hazard draw at the early stage. Hazard Aalysis Techology The safety activity of railway sigalig systems defied by the iteratioal stadards meas a series of all activities which fid ad elimiate potetial hazards embedded i the railway sigalig systems beig developed, or establish measures so that they ca be reduced to below allowable level, ad reflect them to the desig ad developmet of system. FIG. 2 SAFETY ACTIVITY PROCEDURE WITHR SYSTEM LIFE CYCLE FOR SIGNALING SYSTEM FIG. 1 HAZARD MANAGEMENT PROCEDURE FIG. 1 is the oe showig the process of safety activity i this aspect of hazard maagemet briefly. That is, the safety activity of system requires the idetificatio of hazard, hazard risk evaluatio, ad the hazard risk cotrol to maage it at the allowable level show by the hazard, ad its verificatio process. This process will be carried out repeatedly util the feedback of each stage is always doe ad the hazard is draw, cotrolled to make it to the allowable level ad validated. FIG. 2 is the oe showig the safety activity stage for sigalig systems draw through relevat iteratioal stadards ad aalysis o the precedig studies, etc., ad it is the FIGure showig the compariso with each stage of system life cycle preseted i the IEC 62278, ad the mai outputs by each stage of safety activity together. As explaied previously, the hazard maagemet activity of sigalig system is based o the idetificatio of hazard, ad it is the procedure where draw hazard is aalyzed ad cotrolled. There are very may techiques such as PHL(Prelimiary Hazard List), PHA, HAZOP, FMEA(Failure Mode Effect Aalysis), etc. i the activities ad methods to draw this hazard. Amog these techiques, PHL ad Amog these techiques, PHA ad HAZOP techiques are the well used method to idetify the hazard, ad IEC 62425 which is the iteratioal stadard related with the safety of railway sigalig system ad the Yellow Book of Bitish railways recommed to utilizig it as the meas for hazard aalysis. PHA is methods to idetify the early stage hazard, ad the HAZOP are used as detailed methods to draw hazards based o the hazard draw at the early stage. The PHA is method to idetify the early stage hazard, ad the HAZOP is used as detailed methods to draw hazards based o the hazard draw at the early stage. But the geeral HAZOP techique has some weakess to apply as it is to railway sigalig, we proposed the modified HAZOP techique ad applied to idetified the hazards i this paper. The idetified hazards from above two methods have to be aalyzed the cosequece to obtai the deleted or mitigated measures o hazard risk. The cosequece aalysis o idetified hazards was executed usig ETA(Evet Tree Aalysis) method. This paper studied applicatio techology of PHA ad HAZOP techique to the sigalig systems to draw the hazard which is the most fudametal stage i safety activities, ad ETA to aalyze the hazard cosequece. 33
www.ijape.org Iteratioal Joural of Automatio ad Power Egieerig (IJAPE) Volume 2 Issue 2, February 2013 HAZOp-R Techology Geeral HAZOP Techique HAZOP techique is the formalized systematic techique to draw the hazard, ad it aalyzes the cause ad result for the case where specific parameter is out of it i accordace with the guide word. The most importat techology i the deductio of hazard is to aalyze the cause ad result of hazard, ad if HAZOP is used i this stage, the hazard ca be draw usefully at the early stage of safety aalysis procedure[iec 61882][Redmill, 1997]. HAZOP uses the cocept of guide word to draw the hazards of system. Guide words such as More,, Less, etc. idetify deviatios possible to be out of itetio of the desig by combiig with various coditios of system i the course of drawig hazards ad fid the occurrece of hazard. The purpose of HAZOP is to aalyze ad verify deviatios of system possible to be occurred from plaed itetio of operatio to the special use of guide words. This potetial system deviatio ca be developed to the accidet. HAZOP icludes sufficiet explaatio about the system to prove how deviatios ca be occurred from the itetio of desig, ad the systematic survey o the whole parts of it. Oce verified, the aalysis will be made with respect to whether these deviatios ad results accordig to them ca have a adverse effect o the safe ad efficiet operatio of system. HAZOP icludes sufficiet explaatio about the system to prove how deviatios ca be occurred from the itetio of desig, ad the systematic survey o the whole parts of it. Oce verified, the aalysis will be made with respect to whether these deviatios ad results accordig to them ca have a adverse effect o the safe ad efficiet operatio of system. This geeral HAZOP techique is the techique iitially developed i the chemical process ad has bee advaced, ad parameters ad guide words are cosisted of items such as chage i the qualitative trasformatio amout. Although parameters ad guide words are suitable for the chemical process where the cotrol of liquid or gas, etc. is doe geerally, i case of trai cotrol system almost all of whose cotrol outputs are digital sigals ad cotrol targets were mostly made up with digital values, there are some parts ot suitable for applyig these geeral parameters ad guide words. Due to these iappropriate parameters ad guide words, it has the problem such as failure to make the best use of merits of HAZOP techique sufficietly, or applicatio of some parts of guide words by iterpretig them arbitrarily, etc. i the hazard aalysis of trai cotrol systems. HAZOP R Techique The digital cotrol based sigalig system has its limitatio to coduct accurate hazard aalysis oly with the aalysis o deviatios i accordace with the qualitative chages such as More, Less, etc. based o the temperature, pressure ad liquid, etc. That is, may facilities located at various locatios such as trackside, o board ad cotrol ceter, etc. are beig operated geerally i the sigalig systems, ad almost all of iput/output sigals are cosisted of digital sigals. I additio, the sigalig system is the facility i charge of the safe drivig of trai, ad it has differet characteristics from geeral chemical process system i that the hazard becomes a importat problem i coutermeasure procedures at the time of emergecy ad the cotets to be reflected i the system accordig to it, etc. This paper proposed ew parameters ad guide words to suit for applyig to the sigalig systems while utilizig existig HAZOP cocepts ad procedures as they are, ad called it as HAZOP R[12]. Accordigly, the applicatio case for oe hazard of actual sigalig system will be described. Parameters i the HAZOP techique mea the physical, temporal, operatioal variables where guide words ca be applied, ad although they are applied i the plat idustry by beig classified as specific parameter ad geeral parameter as follows, these parameters are the parts ot suitable for the trai cotrol systems. Parameters iteded to be applied to HAZOP R were proposed as TABLE 1. Geeral HAZOP guide words is composed as mai guide words like quatitative amout of chages i gas or liquid, etc., it is difficult to apply these guide words to the sigalig systems as they are. It is possible to apply the fuctio of guide word after chagig it to suit for sigalig systems if these guide words are applied as they are, ad i this case, sice characteristics of trai cotrol system are ot reflected i it, systematic hazard aalysis caot be accomplished. Therefore, we proposed guide words suitable for trai cotrol systems like TABLE 2. 34
Iteratioal Joural of Automatio ad Power Egieerig (IJAPE) Volume 2 Issue 2, February 2013 www.ijape.org TABLE 1 PARAMETERS FOR HAZOP R TABLE 2 GUIDE WORD FOR HAZOP R. Parameter Descriptio Guide word Descriptio Related parameter 1 Iterface 2 Time Data iterface betwee wayside equipmet ad o board equipmet Commuicatio iterface betwee the wayside operator ad vehicle driver Data iterface betwee sub systems Data iterface betwee related systems Commuicatio iterface betwee the wayside operator (system) ad maitaier operatio time based o the trai schedule Operatio time of the o site facilities Software processig time Geerally defied time, t, e Part of Early Late More Less There is o defied parameter. Performed or cosidered partly Performed earlier tha defied time Performed later tha defied time Excess ad icrease of the variables Shortage ad decrease of the variables Other tha Abormal parameter Iterface, Time, Actio, Limit, Procedure, Data Actio, Outside, Data Time, Actio, Data Time, Actio, Data Limit, Data Limit Procedure, Iterface, Actio, Limit, Procedure, Outside, Data Whe defiig deviatios i the trai cotrol systems i combiatio with parameters ad guide words defied previously, it is like TABLE 3. TABLE 3 DEVIATION FOR HAZOP R Operatio of operator, driver, maitaier Devi atio Part of Early Late More Less Other 3 Actio 4 Limit Actio of o site facilities Actio of o board equipmet Limit to the trai speed Limit to the lie capacity Limit to the software processig Limit to the huma labor Limit to the availability ad reliability of facility Operatio, drivig, maiteace procedure 5 Procedure Coutermeasure procedure at emergecy 6 Outside 7 Data Natural pheomea (earthquake, storm, sow, rai, etc.) passeger behavior Prerequisite to the itetioal exteral obstacle Cotrol commad (trai cotrol, o site facility cotrol, etc.) O site iformatio Database iformatio Iter face Time Acti o Limi t Proc edur e Outs ide Iterface impossib le defied time actio defied limit procedur e Data Act partly Part of procedur e oly existed Exteral factor acts partly Oly part of created, trasmitt ed, received Earlier tha defied time Quick operatio ad actio Quick creatio, trasmissi o, receipt later tha defied time Late operatio ad actio Late creatio, trasmis sio, receipt Exceed defie d limit Excessi ve creatio, trasm issio, receipt Fall short of defie d limit Abormal Iterface Other abormal operatio ad actio Other abormal limit Abormal procedure Abormal exteral factor Other abormal 35
www.ijape.org Iteratioal Joural of Automatio ad Power Egieerig (IJAPE) Volume 2 Issue 2, February 2013 Idetificatio of Hazards The first step hazards are draw by PHA techique i the previous descriptio, ad the detailed hazards are idetified by HAZOP R oe. HAZOP R techique to the hazard aalysis of railway sigalig system ca perform the safety activity for both hardware ad software as sigal related sigalig system amog various railway systems. DCM shall be composed i the redudacy system ad it shall maitai its trai distace cotrol fuctio by covertig to the secod system automatically if the first system lost its fuctio. EIM shall be composed i the redudacy system ad it shall maitai its iterface fuctio with exteral system by covertig to the secod system automatically if the first system lost its fuctio. FIG. 3 BLOCK DIAGRAM OF CRD SYSTEMS AS A TARGET SYSTEM Target system to study is the sigalig system performig the trai route cotrol ad trai distace cotrol through iterlockig logic, ad it is referred to as CRD(Cotrol Route & Distace) system. FIG. 3 shows the fuctioal block diagram of. Basic cocept of is as follows. Track method shall be the logical block method which classifies existig track virtually by software, ot the block track method which classifies existig track physically by track circuit. That is, logical blocks are blocks defied by software ad they are ot those preset withi the track physically. Therefore, it must be composed i the mock up by classifyig tracks properly by software with the target statio as its target. Implemets the virtual traspoder amog trackside equipmet to verify the trai locatio i the o board simulator. ICM shall be composed i the redudacy system ad it shall maitai its trai route cotrol fuctio by covertig to the secod system automatically if the first system lost its fuctio. FIG. 4 SYSTEM CONFIGURATION OF CRD SYSTEMS is the cotrol system to make iterlockig system such as trai distace cotrol ad route commad processig for the trai protectio which is the importat fuctio of sigalig system carried out, ad it is cosisted of various simulators for the iterface of such as o board simulator, sigalig equipmet cotrol simulator, etc. with actual o site sigalig equipmet or o board equipmet, etc. performs o site cotrol commad processig fuctio such as processig of the route setup cotrol commad, etc. which is received from ATS simulator, fuctio of receivig ad processig o site sigalig equipmet status, fuctio of receivig ad processig trai operatio iformatio from the o board simulator(atp), ad the automatic trai protectio fuctio, etc. such as processig of trai distace cotrol for simulated trai operatio of o board simulator(atp). CPU module i charge of the core fuctio of shall be classified ito EIM(Electroic Iterlockig Module) which is i charge of the iterlockig fuctio such as route 36
Iteratioal Joural of Automatio ad Power Egieerig (IJAPE) Volume 2 Issue 2, February 2013 www.ijape.org cotrol ad DCM(Distace Cotrol Module) which is i charge of the trai protectio fuctio such as trai distace cotrol. The actual cofiguratio of CRD system is show FIG. 4. Prelimilary Hazard Aalysis PHA aalysis techique is the startig stage of hazard cotrol which fids out ad aalyzes hazards possible to be occurred i each of the systems. PHA will aalyze potetial hazards which ca be occurred i the system by drawig hazards to be draw i the prelimiary desig stage. Aalysis is performed o the basis of higher level documets for the fuctio ad cofiguratio of target system ad the etire iterface of huma beig with other systems. Hazard aalysis activity to be performed durig the PHA process shall perform the iitial stage evaluatio o the severity of draw hazards ad frequecy of occurrece. Results are used to determie where the quatified aalysis will be ecessary i the future, ad they make the complete aalysis ad risk evaluatio possible to be performed through repetitio ad complemetatio accordig to the progress i detailed desig of system. The start of PHA aalysis is the PHL which is the collectio of idetified hazards, ad PHA aalyzes these hazards i more details. Additioally, desig iformatio is compared with the hazard checklist to idetify the hazard which was ot predicted i advace. Ad the PHA output icludes the desig method which was established to remove or mitigate idetified hazards ad system safety requiremets. Sice PHA starts i the early stage of project i the desig stage, the usable are i the icomplete level. I case where these icomplete are modified ad complemeted, they must be modified ad added i the ext stage accordigly. After drawig hazards, the process which establishes causes ad measures agaist them must be performed. Sice it is the stage where the desig was ot accomplished cocretely yet, the measure to be established caot be detailed also. We drew the highest level 4 hazards for hazard aalysis as follows with based o explaied i the previous PHA aalysis as its target. Amog of them, a example hazard is shows i TABLE 5. Amog them, oe example hazard is show i TABLE 5. Hazard 1 : was etered ito the abormal route Hazard 2 : Aother trai was etered withi the permitted movemet authority Hazard 3 : Directio of poit machie was coverted durig the movemet of trai Hazard 4 : drivig too fast at the abormal speed TABLE 4 PHA RESULTS ON HAZARD 2 OF CRD SYSTEMS Hazard Causes Effect Mitigatio Hazard 2 : Aother trai was etered withi the permitted movemet authority HAZOP R Failure i settig the permitted movemet authority of trai Failure i trai brake (emergecy brake) Failure i idetificatio of trai locatio Perform the validatio o block setup, validatio o trai locatio, ad validatio o trai status to set the permitted authority. movemet Receive iformatio o the o board equipmet status cotiuously ad supervise it. Perform the validatio o trai locatio. The result of HAZOP for the trai operatig i the directio of route that is ot the defied route, which is the first hazard, is show i TABLE 7. Causes ad measures agaist situatios where the etry of trai ito the wrog route ad the movemet of trai i the wrog directio ca be occurred due to the failure i cotrol of trai route, which is oe of the mai fuctios of, were established. Total of three parameters applicable to the hazard ad two guide words were applied. Ad they were aalyzed as the case where the iformatio o trai locatio caot be idetified due to the iterruptio of iterface betwee CRD ad trai or where the movemet authority caot be trasmitted, ad as the cases caused by the abormal operatio of poit machie ad abormal cotrol commad. The hazard aalysis through HAZOP R made the highest hazard of which was draw from the defiitio o the highest fuctio as its target for aalysis. After this hazard idetificatio, cosequece aalysis by idetified hazard will be executed through ETA method o it, ad it will go through a process to hazard maagemet. Ad it will go through the stage where the allocated safety requiremet, ad the mitigatio techologies preseted i the course of 37
www.ijape.org Iteratioal Joural of Automatio ad Power Egieerig (IJAPE) Volume 2 Issue 2, February 2013 hazard aalysis are reflected to the system desig. TABLE 5 HAZOP R RESULTS FOR HAZARD 1 OD CRD SYSTEMS Hazard 1 Param eter Iterfa ce Actio Data Guid e word Oth er Oth er Deviat io iterfa ce t operat ed Abor mal operati o Abor mal was etered ito the abormal route Causes Failure i idetificatio of trai locatio Failure i receipt of trai route setup commad Failure i trasmissio of movemet authority for trai Failure i switchig of poit machie Switchig of poit machie i the wrog directio Failure i iformatio o movig directio of trai Error i settig movemet authority for trai Error i settig trai route Error i commad to switch poit machies Descriptio Approach betwee trais caot be idetified due to the uavailability of idetifyig trai locatios Uable to receive a route setup commad from ATS Failure i trasmittig a movemet authority for trai to the o board etered ito the usafe directio sice the poit machie was ot operated etered ito the usafe directio sice the poit machie was switched i the wrog directio Omissio of iformatio o directio of trai movemet from Cose quec es Stoppa ge of trai Mitigatio Emergecy stop of trai if it is impossible to iterface with the trai Redudacy desig of Emergecy stop of trai if it is impossible to iterface with the trai Idetificatio of iformatio o failure of poit machie Idetificatio of iformatio o failure/directio of poit machie Redudacy desig of Settig of movemet Redudacy desig of authority for trai differet from the trai route setup Approach to the other trai due to Redudacy desig of the wrog route setup of trai etered ito the usafe route due to the Redudacy desig of abormal switchig of poit machie aalysis is to draw cocrete defese measures which ca suppress the potetial icrease of hazard as follows. Physical measures such as the techical diagosis, warig, cotrol, ad protectio system Procedural egieerig measures such as the rules, procedures, ad process kowledge of operator Derivatio of eviromet which ca defed uiteded accidets Cocept of cosequece aalysis ca be expressed as the FIG. below. FIG. 5 CONNECTIONAL PROCESS OF CONSEQUENCE ANALYSIS The ETA(Evet Tree Aalysis) method is applied to the cosequece aalysis for the idetified hazards o s. The ETA method is kow as a popular approach to cosequece aalysis of vital systems. Result o performace of cosequece aalysis o hazard of target evaluatio system by above described ETA method is as follows. Results of cosequece aalysis o target evaluatio system Hazard 3 were draw i the ratio of 30.5% for trai, 5% for stoppage of trai, ad 64.4% for the safety status. That is, the safety i the level of 70% ca be guarateed if we ca cope with it systematically by receivig the speed, locatio ad status iformatio, etc. from the trai, eve though the trai eters ito the abormal route. Therefore, the most importat thig i the Hazard 3 is to prepare the pla which ca secure the iterface with the trai to the maximum. Cosequece Aalysis of the Idetified Hazards Aalysis o causes ad cosequeces of occurrece must be performed for the draw hazards of target system, ad the degree of risk accordig to it must be calculated. Cosequece aalysis to be applied to the hazard is performed by the questio like what if the hazard is occurred? Purpose of the cosequece aalysis is to draw, record ad quatify possible cosequeces which ca be excluded from the hazards. The most importat matter i the cosequece FIG. 6 CONSEQUENCE ANALYSIS OF TARGET SYSTEM HAZARD 1 38
Iteratioal Joural of Automatio ad Power Egieerig (IJAPE) Volume 2 Issue 2, February 2013 www.ijape.org Coclusio The PHA ad HAZOP are recommeded i the related iteratioal stadards to draw ad aalyze hazards amog safety activity stages of railway sigalig systems. However, sice idetificatio of hazard through amog of them HAZOP techique is the techology developed i the chemical process field, parameters ad guide words to be used i this techique are ot suitable to be applied to sigalig systems. This paper preseted parameters ad guide words suitable for sigalig systems o the basis of this fudametal HAZOP techique, ad its applicability was verified by applyig it to sigalig systems beig developed actually. As its result, it was verified that the umber of causes were remarkably icreased i compariso with causes draw by existig geeral HAZOP method, ad i additio, it was verified that the hazard idetificatio ad aalysis o sigalig system based o the proposed parameters ad guide words are efficiet. Sice this could classify ad iquire ito the cause i details which made oe hazard occurred due to the defiitio of parameter ad guide word suitable for sigalig systems, ad it was possible to draw more effective ad detailed result. We could establish the procedure for applyig the hazard idetificatio of railway sigalig system through the cosequece aalysis accordig to the derivatio of hazard ad ETA by these PHA ad HAZOP R. REFERENCES E Habibi, M Zare, A Barkhordari, SJ Mirmohammadi, GhH Halvai, Applicatio of a Hazard ad Operability Study Method to Hazard Evaluatio of a Chemical Uit of the Power Statio, Joural of Research i Health Scieces, Vol. 8,. 2, 2008. IEC 61508, Fuctioal safety of electrical/ electroic /programmable electroic safety related systems, 1998. IEC 61882, ʺHazard ad Operatbility Studies(HAZOP Studies) Applicatio Guideʺ, 2001. IEC 62278, ʺRailway Applicatios The specificatio ad demostratio of RAMSʺ, 2002. IEC 62425 Ed. 1, ʺRailway Applicatio: Commuicatios, sigalig ad processig systems Safety related electroic system for sigaligʺ, 2005. J. G. Hwag, H. J. Jo ad D. H. Kim, Hazard aalysis of trai cotrol system usig HAZOP KR methods Iteratioal Coferece o Electrical Machies ad Systems(ICEMS 2010), 2010. KRRI Research Report, Evaluatio of Safety Performace of Cotrol System ad the Techical Developmet of Prevetio agaist Accidet, Jue 2011. M. Y. h, et al., Kowledge Framework ad Algorithm for Automatig HAZOP Aalysis of Batch Processesʺ, Joural of the Korea Istitute of Chemical Egieers, vol39,.3., 2001. RailTrack, ʺEgieerig Safety Maagemet Issue 3ʺ, Yellow Book 3., 2000. Redmill F., Chudleigh MF, Catmur JR., Priciples uderlyig a guidelie for applyig HAZOP to programma ble electroic systems, Reliability Egieerig & System Safety i Elsevier, Vol.55,. 3, pp. 283 93, 1997. Sriivasa R., Vekatasubramaia V., ʺAutomatig HAZOP aalysis of batch chemical plats : Part I. The kowledge represetatio frameworkʺ, Computers chem. Eg. Vol. 22,. 9, pp.1345 1355 (1998) Vekat Vekatasubramaia, Jisog Zhao, Shakar Viswaatha, Itelliget systems for HAZOP aalysis of complex process plats, Computers ad Chemical Egieerig, Vol. 24, pp. 2291 2302, 2000. Jog Gyu Hwag received the B.S ad M.S. degrees i Electrical Egieerig from Kokuk Uiversity, Korea i 1994 ad 1996, respectively. He has bee workig towards his Ph.D. i the Divisio of Electrical ad Computer Egieerig, Hayag Uiversity sice the year 2000. As of 1995, he has bee a Pricipal Researcher with the Korea Railroad Research Istitute. He was a visitig scholar at Virgiia Commowealth Uiv. from 2011 to 2012. His research iterests are i the areas of railway sigalig system, computer etwork techology, PRT(Persoal Rapid Trasit) system, software testig of embedded system. Hyu Jeog Jo received the B.S. degree from the Hakuk Aviatio Uiversity, Goyag, Gyoggi do, Korea, i 2003. She worked toward the M.S. degree at the Gwagju Istitute of Sciece ad Techology (GIST), Gwagju, Korea. Sice 2005, she has bee egaged with the Cotrol System Research Team of the Korea Railroad Research Istitute (KRRI). His research iterests the areas of railway sigalig, software safety, commuicatio applicatio techology. 39