RFID Technology and its Advantages

Transcription

1 Applyng RFID Technology n Buldng Mantenance Chen-Ho Ko, PhD Natonal Pngtung Unversty of Scence and Technology Pngtung, Tawan Informaton technology applcatons have proven effectve n the mantenance of constructed facltes. The objectve of the study s to enhance buldng mantenance usng Rado Frequency Identfcaton (RFID) technology. A data management module s frst developed to collect buldng usage and mantenance data. A statstcal module s then establshed to graphcally dsplay the collected data. To ensure that buldng functons perform normally, mantenance actvtes are arranged usng a schedulng module. These three modules are ntegrated nto a web-based RFID buldng mantenance system. System performance s valdated usng a real buldng. Expermental results show that ntegratng RFID technology wth a web-based system, database, and schedulng theory can mprove faclty and equpment mantenance effcency. Key Words: Facltes Management, Rado Frequency Identfcaton (RFID) Technology, Web-Based Management Informaton System, Schedulng. Introducton Deconstructng old buldngs requres tremendous cost, ncludng deconstructon works and waste dsposal. One of the ways to extend the lfe of constructed facltes s to mantan them wth correspondng mantenance systems (Barco, 994; Djerdjour, 2005). Rado Frequency Identfcaton (RFID) technology s one of the most mportant technologes developed n the last century, characterzng repettve read/rewrte, non-contact, and the ablty to access multple tags smultaneously (Hunt et al., 2007). Ths has been regarded as a promsng method to mprove mantenance effcency (Fontelera, 2005). RFID has been wdely used n varous knds of applcatons, such as lbrary book management, warehouse management, asset trackng, and securty control (Nga & Rggns, 2008). A few studes can be found n faclty and equpment management. Strassner and Chang (2003) appled RFID technology to collect data on ol drllng ppes. They montored ppe usage and provded the collected nformaton for nventory control. These researchers found that applyng RFID n drll ppe management greatly reduced ol drllng operatng costs. Cardellno and Fnch (2006) examned nnovatons n facltes management. They pnponted that RFID s a promsng nformaton technology (IT) n the feld. Wng (2006) nvestgated RFID technology applcatons n constructon and facltes management. A case study dscussed n the paper collected data usng RFID tags and passed nformaton through the Internet. The objectve of ths study s to develop a web-based RFID buldng mantenance system to enhance mantenance effcency. To acheve ths goal, RFID technology s nvestgated frst. The RFID and bar code system propertes are dscussed. Three modules, namely data management, statstcal, and schedulng modules are establshed accordng to the buldng mantenance needs. The effcency of the proposed system s examned usng a real case. Applcaton results and conclusons are documented n ths paper. Rado Frequency Identfcaton (RFID) Technology RFID technology s a wreless sensor technology based on electromagnetc sgnal detecton (McCarthy et al., 2003). One of the earlest papers explorng RFID was wrtten by Harry Stockman Communcaton by Means of Reflected Power publshed n 948 (Stockman, 948). Ths came after rado research undertaken durng the Second World War. Today RFID s a generc term for technologes that use rado waves to automatcally dentfy people or objects. A typcal RFID system, as shown n Fgure, s comprsed of three components: an antenna, a transcever, and a transponder. Fgure shows that the transponder (RF tag) s electroncally programmed wth unque nformaton.

2 Rado sgnals are emtted by the transcever through the antenna. Antennas establsh communcaton between the tag and transcever. The RF tag s actvated and data on t are read and wrtten by the requested sgnals sent from the antenna. The RF tag transfers data accordng to a specfc request. The transcever s responsble for data acquston. The data can then be transferred to any computer system for processng (Domdouzs, 2007). The antenna can be packaged wth the transcever nto a reader/wrter unt. The reader/wrter can be mplemented ether as a handheld or fxed-mount devce. The rado wave ranges emtted from the devce depends on the power output and rado frequency. Bar codes have been the most frequently used system for facltes management (Bravman, 987; Terez, 992). In a bar code system, labels must be so postoned that they can be detected and dentfed by a laser scanner. Objects that obstruct the optcal communcaton between the label and scanner nterrupt barcode scannng. Besdes the physcal lmtatons, bar code labels usually have generous dmensons. Unlke bar codes, RFID technology can dynamcally transmt and receve nformaton to help dentfy objects wthout lne-of-sght. Informaton stored n the tag can be modfed, whch provdes flexblty for manageral modfcaton. Informaton Technology (IT) n the form of RFID s thus regarded as a resource that can be appled n overcomng the problems assocated wth tradtonal solutons (alphanumercal codes and bar code labels) (Regatter et al., 2007). Transmsson power Recepton power Transcever Antenna Request Data recepton Request recepton Data transfer Transponder (RF tag) Fgure : Typcal RFID system. System Development Applcaton Scenaro and Requrements RFID technology s employed to mprove the effcency of tradtonal buldng mantenance solutons. The frst step n system development s the scenaro desgn. The mantenance staff carres a tablet PC whle executng mantenance actvtes. A portable RFID reader/wrter s attached to the tablet PC. The staff can mplement mantenance jobs usng a web-based applcaton through an Internet browser. Usng the web-based software, staff can read/wrte nformaton from/nto tags. Informaton related to mantenance jobs are accessed from a sngle database through the Internet n real-tme. As a result, multple users can mantan varous knds of objects at the same tme. To further mprove workng effcency, staff can setup mantenance perods for each tem. The software can remnd users about whch tems requre attenton and automatcally arrange mantenance sequences. Mantenance preparaton and effort can therefore be reduced. Three modules.e. management, statstcal, and schedulng are obtaned accordng to ths scenaro. System Development Process The web-based RFID buldng management system development process s llustrated n Fgure 2. Each actvty s explaned as follows.. Determne hardware and software: System hardware and software that conform to applcaton requrements are nvestgated n the frst step. ASP.NET s chosen as the development platform to establsh the web-based applcaton. ASP.NET s a new technology developed by Mcrosoft. It supports browsers that execute on varous knds of platforms ncludng personal computer, cell phone, personal dgtal assstant (PDA) etc. A portable RFID

3 reader/wrter, namely UHF-Block, manufactured by Ensyc Technology s selected. Ths devce s compatble wth the GEN2 protocol and can be connected usng USB nterface. Fgure 3 represents devces for the staff to mplement mantenance work. The system hardware and software used for system development are summarzed as follows: Web and database server: Dell enterprse personal computer. Integrated development envronment: Vsual Studo.NET (C#.NET). Operaton system: Wndows XP professonal. Database format: Mcrosoft Access. Tablet PC: HP 270P. RFID devce: UHF-Block. RFID tag: UHF G2.. Determne hardware and software 2. Establsh database schema 3. Construct the web system 4. Valdate system 5. Deploy system Fgure 2: Development process of RFID buldng mantenance system. Fgure 3: Mantenance kt. 2. Establsh database schema: Buldng mantenance nduces numerous records. For manageral convenence, nformaton s stored n a sngle database. The database s desgned usng thrd normal form of the relatonal model (Codd 990). The smplfed database schema s represented usng class dagram depcted n Fgure Construct the web system: Ths web-based system s programmed usng C#.NET and transferred through Http/Https protocols. 4. Valdate system: System applcablty s valdated usng a real case. 5. Deploy system: The developed web system s mplemented n a real buldng. Data Management Module The data management module s desgned to allow manpulatng the data stored n the system database. Functons provded by ths module are summarzed n Table. A mantenance object contans the followng nformaton: category, tem, name, safety degree, durablty, frequency of use, purchasng cost, purchasng date, part lst, warranty perod, seller, holder, locaton, etc. Users can fll out the nformaton by enterng values or selectng a proper descrpton from a lst. Each object s dentfed usng RFID code that s a unque dentfcaton number wrtten onto the RFID tag. The RFID code structure s shown n Fgure 5. The codfcaton s desgned for buldng mantenance usng four sectons. The frst secton, category, s used to store equpment or faclty. The second tem stores types of equpment or faclty, such as unversal test machne and electron mcroscope. Thrd part nvolvng four cells s used to store seral number. The fnal area s desgned for future extenson. RFID code s automatcally generated by the

4 module and can be wrtten onto a tag usng the RFID devce. mantenance_record mantenance_records_id mantenance_tem_id date mantenance_cost mantenance_person completon_status note 0..* user employee_id pwd authorty_id name ext 0.. * authorty authorty_id descrpton..* mantenance_tem mantenance_tem_id management_tem_id tem actvty duraton nterval..* management_tem management_tem_id tem_id status frequency employee_id purchasng_cost suppler_id warranty purchased_date locaton 0..*..*..* tem category tem_id category_id tem_name category_name 0..* category_id descrpton descrpton..* repar_tem repar_tem_id management_tem_id tem actvty duraton..* repar_record repar_record_id repar_tem_id date reason repar_cost suppler suppler_id company_name contactor address tel Fgure 4: Database schema. Functon Logn Manage user Manage category Manage tem Manage parts Manage object Manage space Vew hstory Manage seller Table Functons of data management module Explanaton Users enter username and password to log onto the web-based system. Two knds of authorzaton are provded n the system: manager and admnstrator. Only admnstratve users can add/edt/remove system users. Users can add/edt/remove categores that are served as the hghest level of mantenance object classfcaton. Users can add/edt/remove tems that are served as the second level of mantenance object classfcaton. Users can add/edt/remove parts for each mantenance tem. Users can add/edt/remove a mantenance object and generate ts RFID code. Users can add/edt/remove a space for mantenance object. Users can vew mantenance record hstory for each object. Object can be dentfed usng a RFID reader. Users can add/edt/remove the seller nformaton for mantenance objects.

5 Category Item Seral number Extenson Fgure 5: RFID codfcaton structure. For searchng for nformaton about a specfc mantenance object, users can query by ts category, name, RFID code, or dentfy t usng RFID devce. The man form of data management module s shown n Fgure 6. Fgure 6: Man form of data management module. Fgure 7: Lne chart of purchasng costs. Statstcal Module Ths study collected numerous data whle mplementng mantenance jobs stored n the system database. However, ths data row s meanngless to users. The objectve of the module s to represent the system database usng statstcal charts allowng users to understand the data dstrbuton and propertes. Ths module provdes four charts for users to observe the data,.e. crcle graph, ogve, bar chart and lne chart. Statstcal graphs can help users understand mantenance status. A recommendaton table s proposed to assst users makng decsons accordng to the graphs, as explaned n Table 2. An example of demonstratng purchasng costs usng lne chart s depcted n Fgure 7. Statstcal group Mantenance object amount Repar frequency Repar cost Object lfe tme Breakdown causes Table 2 Decson Support for Statstcal Graph Decson support Number of objects located n an ndvdual space can be dentfed. Therefore, users can understand the status of mantenance objects such as mssng and broken. Accordng to the graphs, users can recognze the durablty of mantenance objects. The nformaton can be fed back to the procurement department, repar partners, and property holder for preventve analyss. The nformaton can be used to determne whether the mantenance objects should be replaced or not. The procumbent department can also use the nformaton as purchasng reference. Mantenance effcency effects lfe tme of property. It can also be used as another ndex for property durablty. Graphs about breakdown causes are deal for breakdown causes analyss. The nformaton can be used for troubleshootng.

6 Schedulng Module Schedulng nvolves tasks of makng decsons regardng the allocaton of avalable capacty or resources to jobs, actvtes, tasks, or customers over tme. It thus results what s to be done, when, by whom, and wth what equpment (Ko & Wang, 2007). Buldng functons rely on perodc mantenance. Parts wearng out can nduce malfunctons. Worn out parts can be dentfed and replaced by regular mantenance. However, dverse mantenance objects nvolve varous knds of parts, whch ncrease the mantenance complexty. A proper mantenance schedule s thus needed to effectvely accomplsh jobs. The schedulng module developed n ths study focuses on arrangng mantenance sequences. Two strateges are proposed to enhance mantenance effcency: Centralze mantenance tme: The frst strategy enhances mantenance effcency by reducng preparaton tme. Ths strategy avods frequent mantenance wth small batch jobs. It schedules the tme for carryng out mantenance actvtes, such as once a week, once every two weeks, once a month, or even daly mantenance. Ths schedule can be assgned by users. The logc for determnng whch object should be added to the mantenance lst s expressed n Eq. (). If L T, add n thelst () L :Tme dfference ( D C ) between the tme pont the object should be mantaned ( C ) and when t s planned to be mantaned ( D ). T :Extended mantenance perod, whch can be an arbtrary tme. The value s determned accordng to manageral requrements such as natonal holdays, man power, complexty of mantenance work, etc. Mnmze the requred mantenance hours: To accomplsh mantenance actvtes usng the most effectve way, the module mnmzes the total mantenance tme. Schedulng methods can be dvded nto three categores. Mathematcal programmng s prmarly used to solve certan problems. If the problem s dffcult to solve, dspatchng rules can be consdered. However, dspatchng rules arrange sequences usng certan prncples that cannot obtan an optmum soluton for complex problems. Heurstc algorthms are adopted for dffcult, complex, and uncertan problems. Although heurstc methods cannot guarantee obtanng the optmum soluton, they provde satsfactory results wthn an acceptable tme perod. Mantenance schedulng s regarded as a job shop sequencng problem that can be solved usng a mathematcal programmng method. The objectve functon of the schedulng module, shown n Eq. (2), s to mnmze total mantenance tme t. m n Mn t [ ( ) ] (2) j α : Mantenance tme for object. β : Transportaton tme from object ( ) to. The β 0 when. γ : Transportaton tme from space ( j ) to j. The γ 0 when j. j The RFID buldng management software developed n the study s a web-based system connectng wth a sngle database. Therefore, the system s runnng n real-tme and the nformaton provded by the system s up-to-date. Ths advantage also enables multple users to mplement mantenance jobs at the same tme. The mantenance drecton suggested by ths study s depcted n Fgure 8. A sngle staff member can mplement mantenance work usng a top-down or bottom-up approach (as shown n Fgure 8). For two staff members, one can mplement n the top-down drecton and the other bottom-up. For more than two staff members, the two staff member case s carred out and the addtonal staff members mplement mantenance work from ntermedate postons. The module remnds users to take cautous attenton to the work f the job s related to safety consderatons. The schedulng module setup j j

7 form s shown n Fgure 9. Staff A 5 th floor 4 th floor 3 rd floor 2 nd floor st floor Fgure 8: Mantenance drecton. Fgure 9: Schedulng module. Applcaton Pror to usng the developed system, buldng managers should know the basc concepts about RFID and web-based system. Mantenance jobs were carred out by two staff members at the test center. User name, password, and authorty were dentfed frst n the system. RFID codes were automatcally generated by the data management module accordng to codfcaton grammar. Staff members then enter equpment and faclty nformaton wth correspondng RFID codes. When staff members complete the web form, the generated RFID code s wrtten onto the RFID tag. The system automatcally confrms the wrtng success. Faclty and equpment are avalable n the system once the data passes confrmaton. Staff members can then begn manpulatng object data. The schedulng module was launched to automatcally arrange mantenance sequences. Staff members then select tems and fll n the mantenance records n the form. The two staff mode was adopted when executng mantenance jobs. For ths case study, one staff member selected the top-down sequence and the other chose the bottom-up mantenance drecton. Items dsappeared from the form once they were completed. Incomplete tasks remaned on the form for further schedulng. Because the system accesses the database n real-tme, members have up-to-date nformaton shown on the form. Mantenance records and equpment/faclty nformaton can be quered usng the statstcal module. The current practce that arranges mantenance sequences by hand s tme-consumng. In addton, the dentfed sequence may be subject to an addtonal optmzaton effort. The proposed mantenance can automatcally arrange mantenance sequences and enable multple users to mplement mantenance work at the same tme. Therefore, personnel costs and mantenance makespan can be handled. Conclusons Ths paper presented a web-based RFID buldng mantenance system. Three modules were ncluded,.e., data management, statstcal, and schedulng. Users mplement mantenance work usng tablet PCs attached wth portable RFID devces. The proposed system performance was examned usng a materal test center. The followng benefts of applyng RFID technology n buldng mantenance are drawn from real applcatons: ) automatcally dentfyng equpment and faclty ID avods typos and saves operatonal tme, 2) data stored n RFID tags can be easly modfed, 3) non-contact and non-lne-of-sght RFID technology enhances mantenance convenence, 4) RFID tags can be used under practcal challengng condtons such as pant, grme, and dust, and 5) RFID technology cooperates extensvely wth other nformaton technologes. The developed web-based RFID system s one of the frst researches ntegratng RFID technology, database, Internet technology, and schedulng theory n buldng mantenance. The proposed schedulng module s also one of the

8 poneerng works applyng schedulng theory n RFID applcatons. Acknowledgments Ths research was funded by the Archtecture and Buldng Research Insttute (Tawan), whose support s gratefully acknowledged. Any opnons, fndngs, conclusons, or recommendatons expressed n ths paper are those of the author and do not reflect the vews of the Archtecture and Buldng Research Insttute. The wrters would also lke to thank the nvestgated laboratory for supportng ths study. Specal thanks to students who helped: Yu-Xan Ln, Guan-Je Wang, Y-He La, We-Je Chang, Sh-Hong Wang, and Qng-Yuan Ko. References. Barco, A. L. (994). Budgetng for faclty repar and mantenance, Journal of Management n Engneerng, 0(4) Bravman, R. (987). Usng bar codes mproves management control, Electronc Packagng and Producton, 27(2) Cardellno, P. & Fnch, E. (2006). Mappng IT nnovaton n Facltes Management, Electronc Journal of Informaton Technology n Constructon, Codd, E. F. (990), The Relatonal Model for Database Management, Second edton, Addson Wesley, New York. 5. Djerdjour, M. (2005), Assessng and benchmarkng mantenance performance n a manufacturng faclty: A data envelopment analyss approach. INFOR, 43(2) Domdouzs, K., Kumar, B. & Anumba, C. (2007). Rado-Frequency Identfcaton (RFID) applcatons: A bref ntroducton, Advanced Engneerng Informatcs, 2(4) Fontelera, J. (2005), RFID exploraton, Convertng Magazne, 23(9) Hunt, V.D., Pugla, A.& Pugla, M. (2007), RFID-A Gude to Rado Frequency Identfcaton, Wley-Interscence. 9. Ko, C.H. & Wang, S.F. (2007), Overcomng dffcultes n weekly work plannng. Research Journal of Appled Scences, 2(7) McCarthy, J.F., Nguyen, D.H., Rashd, A.M., & Soroczak, S. (2003), Proactve Dsplays & The Experence UbComp Project, Proceedngs of the Ffth Internatonal Conference on Ubqutous Computng, Nga, E. & Rggns, F. (2008). RFID: Technology, applcatons, and mpact on busness operatons, Internatonal Journal of Producton Economcs, 2(2) Regatter, A., Gamber, M., & Manzn, R. (2007). Traceablty of food products: General framework and expermental evdence, Journal of Food Engneerng, Stockman, H. (948). Communcaton by Means of Reflected Power, Proceedngs of the Insttute of Rado Engneers, 36(0) Strassner, B. & Chang, K. (2003). Integrated antenna system for wreless RFID tag n montorng ol drll ppe, Proceedngs of the Internatonal Symposum on Antennas and Propagaton Socety, IEEE, Terez, T.J. (992), Bar codes move nto mantenance management, Hydraulcs & Pneumatcs, 45(4) Wng, R. (2006). RFID applcatons n constructon and facltes management, Electronc Journal of Informaton Technology n Constructon, 7-72.